CA1297618C - Method and apparatus for manufacturing coagulated grains from polymerlatex - Google Patents
Method and apparatus for manufacturing coagulated grains from polymerlatexInfo
- Publication number
- CA1297618C CA1297618C CA000564558A CA564558A CA1297618C CA 1297618 C CA1297618 C CA 1297618C CA 000564558 A CA000564558 A CA 000564558A CA 564558 A CA564558 A CA 564558A CA 1297618 C CA1297618 C CA 1297618C
- Authority
- CA
- Canada
- Prior art keywords
- latex
- polymer latex
- coagulated
- grains
- coagulant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B15/00—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00
- B29B15/02—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00 of crude rubber, gutta-percha, or similar substances
- B29B15/04—Coagulating devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B9/00—Making granules
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/0058—Liquid or visquous
- B29K2105/0064—Latex, emulsion or dispersion
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a method of manufacturing coagulated grains from polymer latex and apparatus for exercising this method, said method being characterized in that a swirl of polymer latex is produced in tank, while holding it at a temperature lower than the softening temperature of the polymer latex particles and while letting the same polymer latex as said polymer latex fall down into the aforementioned swirl liquid surface, a coagulant is added into said latex flowing-down liquid, thereby letting the coagulant disperse and scatter into the latex in the tank; thereafter, with said coagulant thus scattered as the seeds, coagulated layers are grown on their outer surfaces. According to this invention, nearly spherical coagulated grains with a uniform grain size may he obtained, while suppressing possible formation of massive coagulated matters.
The present invention provides a method of manufacturing coagulated grains from polymer latex and apparatus for exercising this method, said method being characterized in that a swirl of polymer latex is produced in tank, while holding it at a temperature lower than the softening temperature of the polymer latex particles and while letting the same polymer latex as said polymer latex fall down into the aforementioned swirl liquid surface, a coagulant is added into said latex flowing-down liquid, thereby letting the coagulant disperse and scatter into the latex in the tank; thereafter, with said coagulant thus scattered as the seeds, coagulated layers are grown on their outer surfaces. According to this invention, nearly spherical coagulated grains with a uniform grain size may he obtained, while suppressing possible formation of massive coagulated matters.
Description
lZ976~8 ~ETHOD A~D APPARATUS FOR MAN'll~ACTURlNG
COAGULATED GRAINS ~ROM POI,Y,~ER l,ATEX
BACKGROUND O~ THE lNVENT10 1. Pield of the Invention:
The present invention relates to a method and apparatus for manufacturing regularly arranged package of coagulated grains by making use of flocculation and coagulation of polymer latex particles obtained by emulsion polymerization, etc.
COAGULATED GRAINS ~ROM POI,Y,~ER l,ATEX
BACKGROUND O~ THE lNVENT10 1. Pield of the Invention:
The present invention relates to a method and apparatus for manufacturing regularly arranged package of coagulated grains by making use of flocculation and coagulation of polymer latex particles obtained by emulsion polymerization, etc.
2. Description of the Prior Art:
When recovering from polymer latex resinous polymer being its dispersed phase, generally, an aqueous solution of coagulant such as inorganic salts, acids, etc., is put into the latex, or conversely, the latex is put into such an aqueous solution of coagulant, whereby the latex is coagulated in the liquid phase and turned into a state of slurry by such an operation as heat treatment, etc., thereafter, to be in the state of powders or grains through dehydration and drying.
However, in~this method, the configuration of powder is amorphous, powder or grain diameter is difficult to adjust and the grain diameter distribution is broad, thus, the substantial amount of fine powders being contained therein. As a result, loss by scattering, frequent occurrence of process trouble due -to~blinding with fine powders, deteriolation of work environment resu~lt;ing from dust generation, increased danger of dust explosion and other untoward incidences have been brought about.
-' - , 129761~
~ or the purpose of overcoming these problems, very ardent efforts ha~e been made in synthetic resin manufacturing field;
for exa~ple, there have been proposed a method for recovering polymer latex as spherical coagulated grains by spraying it into a coagulable atmosphere or a method of recoverin~ spherical coagulated grains by having coagulated grains absorbed in organic solvent droplets dispersed into water phase and, then, through removal of the solvent and solidification of coagulated matters.
The former method is disadvantageous in that its industrial application is difficult for manufacturing grains larger than 500~ m or for manufacturin~ highly heat resistant polymers having softening temperatures higher than 80 C and that it is difficult to closely pack the grain interior, while the latter method has raised problems in the aspects of cost, quality, applicable range, grain characteristics, etc , that in addition to the difficulty in removal of solvent and inclusions and in close packing of grain interior, no organ;c solvents which are compatible with utilization of said method are ~ ,:
available, depending on type of polymers. As a background of development of such a variety of recovery methods, there lies the current of the times that the degree that the acceptability of characteristics such as the partlcle size or its distri~bution or size or packing rate, etc., rather than the phys~ical properties of polymers, influences the quality of the praduct is increasing.
And as a method for obtaining solid by directly drying ~ .
.
' - ."
latex, spray drying or vacuum granulation drying is available and numerous contrivances have been applied. With these methods however, removal of inclusions in the latex is difficult, scale-up of facilities is required, when forming larger grains, and in addition, large amount of thermal energy is necessary with low density latices, resulting in high treating costs; thus, they are largely subject to restriction in the aspect of quality and cost.
On the other hand, the present inventors previously filed a patent application (European Publication No. 0217006) for an invention for obtaining nearly spherical grains as one which will overcome the above-mentioned disadvantages at once, in which coagulated grains grown with coagulant units dispersed and scattered into an aqueous particle colloid, to have the colloidal particles coa~ulated on the outer surfaces of these units, thereby laminating them from inside out.
As a result of subsequent examinations based on the previous invention, they found out the fact that when coagulated grains are intended to have by contionuous operation.
mere continuous supply of polymer latcx and coagulant into a stirring tank will result in formation of a large mass of coagulum and growth of coagulated matters on the tank wall surface, stirrer, etc., or settling and accumulation of formed coagulated grains at the tank bottom, causing blockaded discharge port and the like problems, and the fact that as a consequence, not only continuation of long continuous operation is thwarted, but sometimes yield is extremely lowered, and ` ~`297618 operability being dreadfully impeded. Eurther, when coagulant is mere]y added to the polymer latex liquid surface, the coagulant or the coagulated matters tend to float due to surface tension, forming united grains or amorphous grains, thus inviting reduced yield and lowered product quality.
Accordingly, for realization of industria] production by this coagulation process, there has arisen a need for developing a method and apparatus which enables long and continuous production of spherical coagulated grains with a uniform grain diameter, by providing solutions to the aforementioned problems.
SUMMARY OF THE INVENTïON
An object of this invention is to provide a method and apparatus developed with aims at not only preventing formation of massive coagulated matters, but continuously manufacturing spherical coagulated grains of arbitrary sizes.
Other objects and advantages of this invention will become evident to those skilled in the art from the detailed descriptions hereunder set forth:
The present inventors have, as a result of their assiduous research, found out the fact that while polymer latex is ~caused to flow down into the surface of the same latex which has gotten to be swirling in a tank, a coa8ulant is added into said flowing down latex, to be dispersed and scattered thereinto, thereby causing its coagulation, whereby the abovementioned ob;ect is achieved, and this finding has lead to completion of this invention.
BRIEF DESCRIPTION OF THE DR~h'lNGS
- 1Z976`18 FIG. 1 is a schematic diagram illustrating an ap~aratus for exercising the method of this invention.
DETAILED DESCR_PTION O~ THE I~VENTIO~
A first part of this invention comprises a mcthod for manufacturi ng coa gu I a ted grains from polymer latex characterized in that a polymer latex is caused to be swirling in a tank, while being held lower than the temperature (softening temperature) at which the polymer latex grains unite by fusion, and while letting the same polymer latex as said polymer latex flow down into the surface of the aforementioned swirl at a temperature lower than the aforementioned softening temperature, a coagulant is added into the flowing down liquid of said latex, thereby causing said coagulant to be dispersed and scattered into the latex in the tank; thereafter, with said coàgulant particles thus scattered as seeds, coagulated layers are grown on the outer surfaces thereof, whereby nearly spherical coagulated grains with a uniform grain size are obtained, while suppressing formation of massive coagulated matters.
And a second part of this invention comprises an apparatus for manufacturing nearly spherical coagulated ~rains with a uniform grain si%e characterized in that it is comprised of a tank for~holding the polymer latex therein, an equipment for producing a swirl of latex in said tank, an equipment for etting said polymer latex flow down into the surface of said Iatex swirl and~an equ~pment for adding the coagulant into the flowing down liquid of said latex.
,: ~
~ ~ ~ 5 .
batices to which this invention is appJicab]e are the following ones, for example; substantially they include almos~
all polymer latices which are obtained b~ emulsion or suspension polymerization and which are recoverable in resinous state.
Single or mixed latices of polymer latices formed by polymerization, copolymerization or graft-polymerization of monomer compositions mainly comprising one or two or more members of monomers selected from among the undermentioned monomer groups may be objects to which this invention is applicable. However, unpolymerizable ones are, of course, excluded. Yinyl aromatics such as styrene. monochlorostyrene, dichlorostyrene, ~-methyl styrene, etc.; vinyl cyanides such as acrylonitrile, methacrylonitrile, etc.; acryl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, etc.;
methacryl esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc.; halogenated vinyls such as vinyl chloride, vin~l bromide, vinyl fluoride, etc.; halogenated vinylidenes such as vinylidene chloride, vinylidene bromide, etc.
; acrylic acid, methacrylic acid, itaconic acid, maleic acid, vinyl acetate, ethylene, propylene, butylene, butadiene, isoprene, chloroprene; and cross-linking monomers such as allyl methacrylate, dially phthalate, triallyl cyanurate, monoethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, div~inyl benzene and glycidyl methacrylate.
Further, undermentioned polymer latices to which this inven~tion is applicable are particularly preferable:
(1) Polymer latices obtained by polymerizing monomers , 6 :~ :
iZ976~B
consisting of 20-80 parts (part refers to part by weight hereinafter, unless otherwise specified) of acrylonitrile monomer, 20-80 parts of mixtures of one or two or more me~bers of vinyl chloride, vinylidene chloride, vinyl bromide and vinylidene bromide and 0-lG parts of easily dyeable monomers.
(2) Butadiene base polymer latex consisting of 0-50 % by weight of styrene (% refers to ~ by weight hereinafter, unless otherwise specified ) and 50-100 % of butadiene, (2') Polymer latices obtained bY polymerizing, in the presence of 20-80 parts of butadiene base polymer latex, 20-80 parts of monomers consisting of 0-50 % of acrylic esters, 0-100 %
of methacrylic esters, 0-90 % vinyl aromatics, 0-90 ~ of vinyl cyanides and 0-20 % of other copolymerizable monomers.
When recovering from polymer latex resinous polymer being its dispersed phase, generally, an aqueous solution of coagulant such as inorganic salts, acids, etc., is put into the latex, or conversely, the latex is put into such an aqueous solution of coagulant, whereby the latex is coagulated in the liquid phase and turned into a state of slurry by such an operation as heat treatment, etc., thereafter, to be in the state of powders or grains through dehydration and drying.
However, in~this method, the configuration of powder is amorphous, powder or grain diameter is difficult to adjust and the grain diameter distribution is broad, thus, the substantial amount of fine powders being contained therein. As a result, loss by scattering, frequent occurrence of process trouble due -to~blinding with fine powders, deteriolation of work environment resu~lt;ing from dust generation, increased danger of dust explosion and other untoward incidences have been brought about.
-' - , 129761~
~ or the purpose of overcoming these problems, very ardent efforts ha~e been made in synthetic resin manufacturing field;
for exa~ple, there have been proposed a method for recovering polymer latex as spherical coagulated grains by spraying it into a coagulable atmosphere or a method of recoverin~ spherical coagulated grains by having coagulated grains absorbed in organic solvent droplets dispersed into water phase and, then, through removal of the solvent and solidification of coagulated matters.
The former method is disadvantageous in that its industrial application is difficult for manufacturing grains larger than 500~ m or for manufacturin~ highly heat resistant polymers having softening temperatures higher than 80 C and that it is difficult to closely pack the grain interior, while the latter method has raised problems in the aspects of cost, quality, applicable range, grain characteristics, etc , that in addition to the difficulty in removal of solvent and inclusions and in close packing of grain interior, no organ;c solvents which are compatible with utilization of said method are ~ ,:
available, depending on type of polymers. As a background of development of such a variety of recovery methods, there lies the current of the times that the degree that the acceptability of characteristics such as the partlcle size or its distri~bution or size or packing rate, etc., rather than the phys~ical properties of polymers, influences the quality of the praduct is increasing.
And as a method for obtaining solid by directly drying ~ .
.
' - ."
latex, spray drying or vacuum granulation drying is available and numerous contrivances have been applied. With these methods however, removal of inclusions in the latex is difficult, scale-up of facilities is required, when forming larger grains, and in addition, large amount of thermal energy is necessary with low density latices, resulting in high treating costs; thus, they are largely subject to restriction in the aspect of quality and cost.
On the other hand, the present inventors previously filed a patent application (European Publication No. 0217006) for an invention for obtaining nearly spherical grains as one which will overcome the above-mentioned disadvantages at once, in which coagulated grains grown with coagulant units dispersed and scattered into an aqueous particle colloid, to have the colloidal particles coa~ulated on the outer surfaces of these units, thereby laminating them from inside out.
As a result of subsequent examinations based on the previous invention, they found out the fact that when coagulated grains are intended to have by contionuous operation.
mere continuous supply of polymer latcx and coagulant into a stirring tank will result in formation of a large mass of coagulum and growth of coagulated matters on the tank wall surface, stirrer, etc., or settling and accumulation of formed coagulated grains at the tank bottom, causing blockaded discharge port and the like problems, and the fact that as a consequence, not only continuation of long continuous operation is thwarted, but sometimes yield is extremely lowered, and ` ~`297618 operability being dreadfully impeded. Eurther, when coagulant is mere]y added to the polymer latex liquid surface, the coagulant or the coagulated matters tend to float due to surface tension, forming united grains or amorphous grains, thus inviting reduced yield and lowered product quality.
Accordingly, for realization of industria] production by this coagulation process, there has arisen a need for developing a method and apparatus which enables long and continuous production of spherical coagulated grains with a uniform grain diameter, by providing solutions to the aforementioned problems.
SUMMARY OF THE INVENTïON
An object of this invention is to provide a method and apparatus developed with aims at not only preventing formation of massive coagulated matters, but continuously manufacturing spherical coagulated grains of arbitrary sizes.
Other objects and advantages of this invention will become evident to those skilled in the art from the detailed descriptions hereunder set forth:
The present inventors have, as a result of their assiduous research, found out the fact that while polymer latex is ~caused to flow down into the surface of the same latex which has gotten to be swirling in a tank, a coa8ulant is added into said flowing down latex, to be dispersed and scattered thereinto, thereby causing its coagulation, whereby the abovementioned ob;ect is achieved, and this finding has lead to completion of this invention.
BRIEF DESCRIPTION OF THE DR~h'lNGS
- 1Z976`18 FIG. 1 is a schematic diagram illustrating an ap~aratus for exercising the method of this invention.
DETAILED DESCR_PTION O~ THE I~VENTIO~
A first part of this invention comprises a mcthod for manufacturi ng coa gu I a ted grains from polymer latex characterized in that a polymer latex is caused to be swirling in a tank, while being held lower than the temperature (softening temperature) at which the polymer latex grains unite by fusion, and while letting the same polymer latex as said polymer latex flow down into the surface of the aforementioned swirl at a temperature lower than the aforementioned softening temperature, a coagulant is added into the flowing down liquid of said latex, thereby causing said coagulant to be dispersed and scattered into the latex in the tank; thereafter, with said coàgulant particles thus scattered as seeds, coagulated layers are grown on the outer surfaces thereof, whereby nearly spherical coagulated grains with a uniform grain size are obtained, while suppressing formation of massive coagulated matters.
And a second part of this invention comprises an apparatus for manufacturing nearly spherical coagulated ~rains with a uniform grain si%e characterized in that it is comprised of a tank for~holding the polymer latex therein, an equipment for producing a swirl of latex in said tank, an equipment for etting said polymer latex flow down into the surface of said Iatex swirl and~an equ~pment for adding the coagulant into the flowing down liquid of said latex.
,: ~
~ ~ ~ 5 .
batices to which this invention is appJicab]e are the following ones, for example; substantially they include almos~
all polymer latices which are obtained b~ emulsion or suspension polymerization and which are recoverable in resinous state.
Single or mixed latices of polymer latices formed by polymerization, copolymerization or graft-polymerization of monomer compositions mainly comprising one or two or more members of monomers selected from among the undermentioned monomer groups may be objects to which this invention is applicable. However, unpolymerizable ones are, of course, excluded. Yinyl aromatics such as styrene. monochlorostyrene, dichlorostyrene, ~-methyl styrene, etc.; vinyl cyanides such as acrylonitrile, methacrylonitrile, etc.; acryl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, etc.;
methacryl esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc.; halogenated vinyls such as vinyl chloride, vin~l bromide, vinyl fluoride, etc.; halogenated vinylidenes such as vinylidene chloride, vinylidene bromide, etc.
; acrylic acid, methacrylic acid, itaconic acid, maleic acid, vinyl acetate, ethylene, propylene, butylene, butadiene, isoprene, chloroprene; and cross-linking monomers such as allyl methacrylate, dially phthalate, triallyl cyanurate, monoethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, div~inyl benzene and glycidyl methacrylate.
Further, undermentioned polymer latices to which this inven~tion is applicable are particularly preferable:
(1) Polymer latices obtained by polymerizing monomers , 6 :~ :
iZ976~B
consisting of 20-80 parts (part refers to part by weight hereinafter, unless otherwise specified) of acrylonitrile monomer, 20-80 parts of mixtures of one or two or more me~bers of vinyl chloride, vinylidene chloride, vinyl bromide and vinylidene bromide and 0-lG parts of easily dyeable monomers.
(2) Butadiene base polymer latex consisting of 0-50 % by weight of styrene (% refers to ~ by weight hereinafter, unless otherwise specified ) and 50-100 % of butadiene, (2') Polymer latices obtained bY polymerizing, in the presence of 20-80 parts of butadiene base polymer latex, 20-80 parts of monomers consisting of 0-50 % of acrylic esters, 0-100 %
of methacrylic esters, 0-90 % vinyl aromatics, 0-90 ~ of vinyl cyanides and 0-20 % of other copolymerizable monomers.
(3) Polymer latices obtained by polymeri~ing, in the presence of 0-20 parts of rub~ery polymer latices consisting of 0-50 %
of styrene, 50-100 % of butadiene and 0-30 % of acrylic esters, 80-100 parts of monomers consisting of 0-100 % of methyl methacrylate, 0-60 % of other methacrylic esters exclusive of methyl methacrylate or acrylic esters, 0-90 ~ of ; vinyl aromatics and 0-90 % of vinyl cyanides.
of styrene, 50-100 % of butadiene and 0-30 % of acrylic esters, 80-100 parts of monomers consisting of 0-100 % of methyl methacrylate, 0-60 % of other methacrylic esters exclusive of methyl methacrylate or acrylic esters, 0-90 ~ of ; vinyl aromatics and 0-90 % of vinyl cyanides.
(4) Mixed latices of 0-50 parts of graft copolymers (A) formed by polymerizing 10-90 parts of one or two or more members of mQnomers selected from among vinyl aromatics, methacrylic esters, acrylic esters and vinyl cyanides in the presence of 10-90 parts of butadiene base polymer consisting of 0-50 % of styrene and 50-100 % of butadiene, and 50-100 parts of :
lZ~7618 polymers tB) formed by polymerizing monomers including 0-70 mol % of ~-methyl styrene and 30-100 mol % of one or two or more members of monomers selected from among vinyl aromatics, methacrylic esters, acrylic esters, acrylic acid and vinyl cyanides.
lZ~7618 polymers tB) formed by polymerizing monomers including 0-70 mol % of ~-methyl styrene and 30-100 mol % of one or two or more members of monomers selected from among vinyl aromatics, methacrylic esters, acrylic esters, acrylic acid and vinyl cyanides.
(5) Polymer latices obtained by polymerizing 15-95 parts of one or two or more members of monomers selected from among methacrylic esters, vinyl cyanides, acrylic esters, vinyl aromatics and monomers copolymerizable with these compounds in the presence of 5-85 parts of rubbery polymers obtained by polymerizing 40-100 % of acrylic esters, 0-60 % of one or two or more of monomers selected from among vinyl aromatics, vinyl cyanides, vinyl chloride, vinylidene chloride, vinyl acetate and conjugated diolefins and 0-10 % of cross-linking agents.
(6) Polymer latices obtainsd by polymerizing 40-100 parts of vinylidene chloride and 0-60 parts of one or two or more members of monomers selected from among vinyl aromatics, vinyl cyanides, acryllc esters, methacrylic esters, acrylic acid, methacrylic acid, itaconic acid, maleic acid and cross-linking monomers.
(7) Polymer latices obtained by polymerizing 40-100 parts of ; vinyl chloride, 0-20 parts of vinyl cyanide and 0-60 parts of one or two more members of monomers selected from among vinylidene chloride, vinyl bromide, vinylidene bromide, acrylic esters, methacrylic esters, acrylic acid, methacrylic acid. itaconic acid, maleic acid and cross-linking monomers.
; (8) Polystyrene latices obtained by polymerizing 100 % of :
styrene monomers.
(9) Polymer latices obtained by copolymeri 2 ing monomers including 0-80 ~ of ~-methyl styrene and 20-100 ~ of one or two or more members of monomers selected from among vinyl aromatics, methacrylic esters, acrylic esters, acrylic acid and viny] cyanides.
Coagulants usable in this invention are in the state of liquid or solid and include, e. g., inorganic salts such as sodium chloride, potassium chloride, lithium chloride, sodium bromide, potassium bromide, lithium bromide, potassium iodide, potassium sulfate, ammonium sulfate, sodium sulfate, ammonium chloride, sodium nitrate, potassium nitrate, calciùm chloride, ferrous sulfate, magnesium sulfate, zinc sulfate, copper sulfate, barium chloride, ferrous chloride, magnesium chloride, ferric chloride, ferric sulfate, aluminum sulfate, potassium alum and iron alum, etc.; inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, etc.;
inorganic alkalis such as caustic soda, caustic potash, calcium hydroxide and magnesium hydroxide, etc.; organic acids such as acetic acid and formic acid, etc.; and salts of organic acids such as sodium acetate, calcium acetate, sodium formate and calcium formate. etc.; these compounds may be used in the form of single or mixed solids, liquids, aqueous solutions or solutions in water-soluble organic solvents. Or solids may be added in slurry state bY dispersing them in organic solvents in which they are hardly soluble but which are water-soluble.
The method of this invention is described hereunder:
~;~97618 First, polymer latex is filled in a tank and a polymer latex's swir] is formed. This polymer latex's swirl has the function of rapidly dispersin~ and scattering in the tank the seed grains which serve as seeds in making growth of coagulated grains.
Usable as an equipment for producing a polymer latex's swirl is one which forms a swirl by discharging latex in tangential direction to a stirring tank provided with no baffle plate or a cyclone type conical tank. And equipment usable as a stirring impeller, when a stirring tank provided with no baffle plate is used. may include a disc turbine, fan turbine, Pfaudler type, Brumagin type, propeller and H-type impellers, etc.; however, care is necessary with those which have discs like the disc turbines, for coagulated grains which have formed will sometimes deposit on their discs. And when inclined blades or a propeller impeller is used, and if the ~tirring is done in the up-flow direction, coagulated grains will recirculate in the vicinity of the latex swirl surface, so that they come in contact with the latex filmy downflow liquid, thus tending to form united coagalated grains, which is undesirable. The degree of turbulence of the polymer latex swirl may be set with the impeller Reynolds number d~ n/ v (d: impeller diameter, n:
number of revolution and v kinetic viscosity) as a guide, the range from 5 X103 to S X10~ being preferable. If its value is less than 5 x103, the coagulated grains which have formed tend to~settle and~deposit on the tank bottom; thus, they unite with eich oth~er, causing their discharge port to be blockaded. But if the stirring conditions are such that its value is larger , ~ .
~297618 than 5 x 1~, there will occur such a phenomenon as breakdown of the coagulated grains caused by the mixing impeller or pelling off of the coagulated grains surfaces due to mutual collision of coagulated grains ùnder violent flowing state, which is undesirable; if the breakdown of coagulated grains or the peeling of coagulated grains surfaces lasts long, the coagulant to be contained in each coagulated grain will go out of it, to be dissolved into the polymer latex, finally coagulating the whole of the polymer latex in the tank, thus making the formation of coagulated grains impossible.
~ hen, onto the aforementioned polymer latex swirl, the same polymer latex is caused to flow down in a liquid film state.
The polymer latex film flowing-down liquid containing coagulated matters formed by the addition of a coagulant into the flowing-down liquid falls down into the polymer latex swirl; it has functions of not only fractionalizing the coagulated matters formed in the flowing-down liquid into fine s~ed particles by means of its falling energy but also submerging the seed particles which tend to float under influence of surface tension. The liquid film forming method comprises letting polymer latex flow along a gutter~ or plate and, then, letting the polymer latex fall down from an end of the gutter or plate, thereby forming a filmy liquid. The filmy flowing-down liquid may be produced by discharging polymer latex liquid through a rectangular discharge port or a perforated tube with holes arranged at such a pitch that the discharged polymer latex flows will be immediately united. The ~, , . .
flow-down length of the liquid fiIm is desirably not more than 2 m from the surface of the Polymer latex swirl. If the flow--down length is in excess of 2 m, the amount of air entrained in the flowing-down liquid increases, resulting in violent foaming on the tank liquid surface; therefore, addition of an antifoaming agent, etc., should be contemplated. And the flow-down direction of the polymer latex filmy flowing-down liquid is desirably the same direction as that of the latex swirl; and further, the contacting points between the filmy flowing-down liquid and the latex swirl liquid surface is desirably radial from the tank center. If the flow-down direction is reversed, the latex swirl flow speed will decrease, undesirably leading to increased power consumption of mixing impeller.
Then, a coagulant is added to the filmy flowing-down liquid. If the coagulant is liquid, the addition of the Goagulant may be made by injection through such a spray nozzle as single port nozzle, full cone nozzle, etc., or vibrated nozzle or perforated tube, etc. The bore size of the nozzle or the perforated tube is desirably not more than 3 mm in diameter; if bores larger than this are used, the diameter of the coagulated grains formed will become extremely large, the grain size distribution will be expanded and this will undesirably cause formation of amorphous coagulated grains, not spherical grains. And proper discharge pressure of liquid coagulant should be on such an order that the coagulant does not break through the polymer latex liquid film. If the coagulant pierces the polymer latex liquid film, it causes formation of :....,:...,. -large mass of coa~ulated matters, when it falls down into theswirl liquid surfac e: if the coagu]ant wets the tank wal]
surface, it will fall down along the wall surface, causing the latex to flocculate at the position of latex level, thereby undesirably yielding scale. On the other hand, if the coagulant is solid, powders, granules, crystals, etc., may be quantitatively added by such powder supplying means as belt feeder, screw feeder, roll feeder and vibrating feeder, etc. As for where the coagulant is to be added into the polymer latex filmy flowing-down liquid, it may be added into the flowing-down liquid at whatever position, but desirably, the area spreads in a direction at a right angle to the liquid flowing-down direction. If the adding direction is the same as its flowing down direction, the once coagulated matters will further come in contact with the coagulant, resulting in uneven coagulant concentrations in the coagulated matters, thus facilitating formation of amorphous coagulated grains. In contrast, when the coagulant is added by spreading it at a right angle to the liquid's flowing down direction, the once coagulated matters will go flowing down, without making contact with coagulant again, thus enabling the coagulant concentrations in the coagulated matters to be uniform.
The coagulated matters formed in the flowing down liquid falls down into the latex swirl together with the flowing-down liquid and by its energy, they will be fractionalized to be :
dispersed as coagulated grains. In each of these fine coagulated grains, there is contained a high concentration of , I
,., `
coagulant; while they are staying in the tank for a specified time period, the coagulant will gradually come out, to pile coagulated layers one upon another, thereby getting the coagulated grains go on growing. The fine coagulated grains which have fallen to he fractionalized provide seeds for growing coagulated grains. If the coagulated matters which have fallen together with the flowing-down liquid have been fractionalized and are staying in the neighborhood of the place where they have fallen, other coagulated matters will fall down thereon one after another, thus, tending to form massive coagulated matters and united grains. To forestall this, the latex swirl quick]y carries off the fractionali~ed fine grains from the fall-down position of the latex filmy flowing-down liquid, to get them diffùsed and scattered, without allowin8 the fine grains containing high concentrations of coa8ulant to be united. When the concentration of the coagulated grains formed is desired to be increased, it is proper to increase the amount of the coagulant added, but as the addition is increased, the increase of the discharge pressure from the nozzle and the concentration of the fine grains containing high concentrations of coagulant near the liquid's falling-in position will become excessive; accordingly, the increase in the formation of massive coagulated matters and the united grains formation frequency is limited and as a countermeasure~ it i9 effective to let flow down the flowing-down liquid at two or three or other plural numbers of~positions.
In the fine grains containing high concentrations of ~: :
. . ,~,.......
coagulant which have been dispersed in the polymer latex swirl, the coagulant existing at the center of each of said grains will move by diffusion to the grain surface, while they are staying in the tank, to have the latex particles coa~ulated and laminated on the grain surfaces: as a result, the coagulated grains will grow larger. ~t this time, the coagulated grains will become nearly spherical coagulated grains closely and regularly packed with polymer latex particles.
The coagulated grains which have grown, while staying for a specified time period in a tank having the polymer latex swirl, are discharged from inside the tank. As the discharging method, a scooping method with a basket or a method of drawing them out as a mixed flow of the coagulated grains and the polymer latex, etc., may be used, but as the coagu]ated grains grow, they tend to sett}e and, therefore, the method of discharging from the tank bottom as their mixed flow with polymer latex is preferable. The coagulated grains formed are discharged, together bi th polymer latex. and only the coagulated grains formed may be taken out by means of such a solid-liquid separating means as an inclined screen separator, vibratory screen separator, etc. On the other hand, the polymer latex separated from the coagulated grains formed is again returned to the tank, to be used as the polymer latex filmy f}owing down llquid.
ccording to this invention, the teMperature of the i po}ymer latex and that of the latex swir]ing and residing in a tank needs to be a temperature lower than its softening . ~,~' .....
1Z~7618 temperature. ~he softening temperature as used here means a temperature at which the latex particles mutually fuse together under atmospheric pressure; generally, it is considered to be the melting point of a substance. However, since definite melting points can not be defined for polymers, they are hardly definable. Even the same polymer's melting point will not be determined by the polymerization degree or its distrihution only, but will be largely influenced by its crystalinity or additives which provide plasticizing effect. However, actually, it is reasonably considered to fall within the range of ~ ( (Tg ~273) / 0.8~ -273 ~ ( (Tg +273) / 0.6, - 273 ~ c, assuming that the glass transition point is Tg (C).
If the coagulated grains are formed in the state of being held at a temperature higher than their softening temperature, the polymer latex particles, being the basic particles, wil}
mutually unite with each other by fusion, giving rise to dispersions in the size and the sphericity of the united grains;
accordingly, they could not be coagulated grains having polymer latex particles fully packed therein in regular arrangement ;, ~ Affordingly, the temperature of the polymer latex ~hen forming , ~ ~
~ ; coagulated grains needs to be lower than its softening m ~ temperature.
In the following. this invention will be described in conjunction with the accompanying drawing:
FIG. 1 is a schematic diagram illustrating an apparatus for use in exercising the method of this invention: Numeral 1 designates a tank for forming a polymer latex swirl; after " ~
.
12976`J 8 filling the tank wi~h polymer latex, a mixing impeller 3 is turned by means of a stirrer driv;ng motor 2, thereby producing a polymer latex swirl in the tank 1. On the other hand, the po]ymer latex is led to the filmy flowing down liquid forming channel 4 through a liquid film forming polymer latex feeding line 13; thereafter, the polymer latex is callsed to flow down from an end of said channel ~, thereby forming a filmy flowing-down liquid 5. Into this flowing-down ]iquid 5, a coagulant is discharged from a coagulant storage tank 8 through a spray nozzle 6, using a coagulant adding pump 7. The coagulated matters formed in the flowing down liquid 5 fall down into the polymer latex swirl liquid surface, to be fractionalized and diffused and scattered in the tank. The coagulated grains which have grown while staying in said tank for a specified time period are discharged together with the polymer latex from the tank bottom through a line 9; then, the mixture is separated into coagulated grains and polymer latex in a solid-liquid separating means like a vibratory screen separator 10 and the coagulated grains thus formed are taken out through another line 11. And the polymer latex after this solid-liquid separation :~ is recycled by means of a liquid fiIm forming latex feeding pump 12, to be reused as the polymer latex filmy flowing-down liquid.
;When forming coagulated grains bY the method and the apparatus of this invention, the coagulated matters which are ~::
formed by adding a coagulant into the polymer latex filmy flowing down liquid are fractionalized by the energy of the : 1 7 ... ,.~,, , - .
.
~ ' . ' .
flowing down liquid, as it is falling into the latex sw;rl, to be fine coagulated grains containing high concentrations of coagulant. At this time, in the fractionalization of coagulated ~atters, the si7,e of the fine coagulated grains containing high concentrations of coagulant may be freely controlled by adjusting the leve] from which the flowing down liquid is caused to fall or the coagulant adding position, depending on the hardness of the coagulated matters, so that not only the formation of massive coagulated matters may be thwarted, but the grain diameter of the coagulated grains thus formed may be adjusted to any arbitrary size. And the fine coagulated grains containing high concentrations of coagulant will be sunk into the latex swirl by the flowing-down liquid;
accordingly, fine coagulated grains containing high concentrations of coagulant will not float on the latex level under the influence of the surface tension, thus foreclosing formation of united grains or amorphous grains. ~urther, the fractionalized fine coagulated grains containing high :
concentrations of coagulant are rapidly shifted due to the polymer latex swirl from the position where the latex flowing~
down liquid has fallen down, so that they go on growing, while flowing along the latex swirl stream line. Accordingly, the coagulated grains while in growth rarely meet and unite with coagulated grains containing high concentrations of coagulant;
thus, this system is quite effective in thwarting formation of massive coaeulated matters and united grains.
As herea~ove described, the present invention enables ,, . ::
, 1~97~i8 controlling the si,e of coagulated grains and thwarting formation of united grains, there~y effect;ng prevention of blockading of discharge port caused by massive coagulated matters or united grains and permitting for a long time stable growth of coagula~ed grains by way of continuous operation.
Since, according to this invention, the latex swirl is always flowing along the tank wall surface, the coagulated grains are running hi thout sticking on the tank wall surface.
Accordingly, this process is entirely free of scaling problem resulting from deposition of coagulated grains on the tank wall surface.
This invention permits spherical grains having arbitrary mean grain diameters to be taken out at the solid-liquid separation time, with a result that generation of fine powders after the drying process which was a disadvantage in the previous method is eliminàted, that powder handling ;s facilitated and that an environment free of dust is realizable at the processing time with these grains, and such other great merits are expectable.
Since, when continuous operation is run, the coagulated grains are taken out of the system by way of solid-liquid separation and will never again return to the tank, the mean coagulated grains forming time is equal to the mean residence time V/F (min), assuming the amount of polymer latex discharged through the polymer latex tank bottom to be F (kg/min), and the amount of the polymer latex in the tank V (kg). ~ccordingly, the coagulated grains forming time will be subiect to control by ~ : ~
~: :
~;: 1 9 ,, .
~297618 operationally adjusting the aforementioned mean residence time, so that adjustment of grain diameter may be made easily, thereby to form coagulated grains with a uniform grain size.
The coagulated grains' mean residence time in the continuous operation preferably fall i-n the range of 2-10 min.
In the fo]lowing, explanations are taken in connect;on with Examples of this invention and a Compal^ison Example, but it will never be restricted thereby.
, .. ~ . . . .
~97618 Example 1 ~ 30 cm inside diameter stirring tank having no baffle plate was filled with 42 kg of polymer latex with solid content of 30 % and held at a temperature of 25 C being a polymer latex having mixed together 33 % cf polymer latex (A) being a polymer latex formed by graft-copolymerizing on butadiene polymer a mixture of styrene, acrylonitrile and methyl methacrylate and consisting of 60 % butadiene, 10 % of methyl methacrylate. 10 %
of acrylonitrile and 20 % of styrene, and 67 % of homocopolymer latex (B) consisting of 20 % of ~-methyl styrene, 25 % of acrylonitrile and 55 % of styrene; then, the latex in the tank was stirred in down-flow direction with three bladed propeller type impeller of 20 cm diameter at 200 rpm, thereby forming a polymer latex swirl. Then the polymer latex was discharged through the tank bottom at a flow rate of 10.5 kg/min, to be again let fall down from an 8 cm wide channel into the latex swirl as a polymer latex filmy flowing-down liquid. At this ~ time, the height from the end of the channel to the latex swirl j level was set at 25 cm. ~hereafter, as a coagulant, 30 %
aqueous solution of calcium chloride was sprayed at 38 ml/min through two 0.6 mm~ single hole nozzles, using a peristaltic feeding pump, to be added into the polymer latex filmy flowing-- down liquid. Through the tank bottom, a mixed floh of the coagulated grains formed and the polymer latex was discharged at ; 10.5 kg/min; then, as it was subjected to solid-liquid -1 separation by the use of a 20 mesh vibratory screen separator, ~ the amount of the coagulated grains only discharged became ; , ; '' ~: ':
.
~ ; 2 1 12~7618 nearly constant 20 min after starting the continuous operation, enabling coagulated grains to be formed at a rate of approx. 2.1 kg per minute. For the amo~nt of polymer latex after subjected to the solid-liquid separation which was reduced by the coa~ulated grain formation, new polymer latex was replenished and this latex was recycled into the tank at a flow rate of 10.
5 kg/min. Accordingly, the mean residence time in this continuous operation was 4 min.
~ hen grain diameter measurement and shape observation of the coagulated grains formed after running continuous operation for 60 min was made, the coagulated grains formed were found to be nearly spherical grains with a uniform grain si2e of 4.4 mm mean grain diameter and no united grains grown by mutual unification of grains ~ere observed.
example 2 After forming a polymer latex swirl under the same stirring conditions, using the same polymer latex and apparatus, as in Example 1, the polymer latex was discharged through the tank bottom at a flow rate of 18 kg/min. Of the latex thus discharged, 10.5 kg/min was let fall down as the polymer latex filmy flowing-down liquid through the same channel as that of Example 1, while the remaining polymer latex was recycled into the tank with another pump. Thereafter, a coagulant was added to the flowing down liquid, using the same apparatus and conditions as in xample 1, thereby forming coagulated grains.
Through the tank bottom, an 18 kg/min mixed flow of the oagulated grains formed and the polymer latex was discharged : ~ :
~ 2 2 anA subjected to sol;d-liquid separation using a 20 mesh vibratory screen separator, whereby 20 min later, coagulated grains were obtained at a rate of approx. 2.0 kg/min. Recycling into the tank was done at a rate of 10.5 kg/min for liquid film formation and 7.5 kg/min directly into the tank, totallin~ 18 kg/min, while supplementing new polymer latex to the separated latex after the solid-liquid separation; accordingly, the mean -residence time in this continuous operation was 2.3 min.
The sample of the coagulated grains formed 60 min later were nearly spherical grains with a uniform grain size 3.2 mm mean grain diameter and almost no united grains were observed.
Examples 1 and 2 clearly suggest that the grain diameter of the coagulated grains formed may be adjusted by altering the mean residence time in the contin uous operation.
example 3 A swirl of polymer latex was formed under the same stirring condition, using the same polymer latex and apparatus, as in Example 1. Then, the polymer latex was discharged through the tank bottom at a flow rate of 10.5 kg/min, to be let flow down into the latex swirl as the polymer latex filmy flowing down liquid. Thereafter, as a coagulant. calcium chloride anhydride grains (grains sifted beforehand which passed 28 mesh.
but retained on 32 mesh screen) were added into the polymer latex filmy flowing-down liquid at a rate of approx. 12.5 g/min b~y a vibrating powder feeder. As a mixed liquid of the coagulated grains formed and the polymer latex was discharged at lZ97618 10~5 kg~min lhrou~h the tank bottom and subjected to solid-liquid separation using a 20 mesh vibratory screen separator, the amount of the coagulated grains only discharged became n,early constant approx. 20 min after starting the continuous operation, enabling the coagulated grains to be formed at a rate of 2.0 kg/min. ~s the grain diameter measurement and shape observation of the coagulated grains was made after 60 min continuous operation while seplenishing fresh polymer latex, the coagulated grains formed were found to be nearly spherical grains with a uniform grain size of 3.8 mm average grain diameter and mutual unification of grains was barely observed.
Example 4 ~ latex swirl was formed under the same stirring condition using the same apparatus, as in Example 1, while holding at 70'c polystyrene latex with solid content of 14 %
which was ohtained by polymerization of styrene monomer only, without using an emulsifier but with ammonium persulfate as a polymerization initator. Then the latex was discharged through the tank bottom at a flow rate of 8.4 kg/min and let fall down into the latex swirl as the latex filmy flowing-down liquid.
Thereafter, the same calcium chloride anhydride as that of Example 3 was added into the filmy flowing-down liquid at a rate of approx. 12.5 g/min by a vibrating powder feeder. Through the tank bottom, a mixed flow of the coagulated grains formed and the polystyrene latex was discharged at 8.4 kg/min: then, as this mixed flow was subjected to solid-liquid separation, using a 20 mesh vibratory screen separator, the amount of the ::
~ s 2 4 ;~ ~
coagulated grains only dischar~ed became nearly constant approx~
20 min after starting the continuous operation, thereby enabling the coagulated grains to be formed at a rate of 1.9 kg/min. As the grain diameter measurement and shape observation of coagulated grains were made, after continuing the operation for 60 min while supplementing polystyrene latex, the coagulated grains formed were found to be nearly spherical grains with a uniform grain size of 3.3 mm average grain diameter.
Comparative Example 1 A 40 Q stirring tank equipped with four baffle plates was filled with 25 kg of the same polymer latex as that of Example 1 and its content was stirred at 200 rpm with 10 cm diameter flat 4 blade turbine impeller. Thereafter, as a coagulant, 30 % aqueous solution of calcium ch]oride was added into the polymer latex liquid surface through a 4 mm~ ID tube at 23 ml/min, using a constant rate pump. From 5 min after starting the addition of coagulant, a mixed flow of the coagulated grains and the polymer latex was drawn out of the tank at a discharge rate of 6.5 kg/min and subjected to solid-liquid separation, using a 20 mesh vibratory screen separator, and the polymer latex was recycled inside the tank at a flow rate of 6.5 kg/min with supplementation of new polymer latex.
When~continuous operation was run under this condition, massive coagulated grains and amorphous coagulated grains were formed in large amounts and even though a 40 mm ~ piping was used for the discharge port, the mixed flow discharge of the coagulated grains and the polymer latex was not smooth, with the discharge ...... .
- ;
l~q6~8 port blockaded 35 min after starting the operation, resulting in shutdown of the operation, As the inside of the tank was observed after the shutdown, a large amount of scale was found to have grown and been sticking on the baffle plates and tank wall liquid surface.
.
: 2 6
; (8) Polystyrene latices obtained by polymerizing 100 % of :
styrene monomers.
(9) Polymer latices obtained by copolymeri 2 ing monomers including 0-80 ~ of ~-methyl styrene and 20-100 ~ of one or two or more members of monomers selected from among vinyl aromatics, methacrylic esters, acrylic esters, acrylic acid and viny] cyanides.
Coagulants usable in this invention are in the state of liquid or solid and include, e. g., inorganic salts such as sodium chloride, potassium chloride, lithium chloride, sodium bromide, potassium bromide, lithium bromide, potassium iodide, potassium sulfate, ammonium sulfate, sodium sulfate, ammonium chloride, sodium nitrate, potassium nitrate, calciùm chloride, ferrous sulfate, magnesium sulfate, zinc sulfate, copper sulfate, barium chloride, ferrous chloride, magnesium chloride, ferric chloride, ferric sulfate, aluminum sulfate, potassium alum and iron alum, etc.; inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, etc.;
inorganic alkalis such as caustic soda, caustic potash, calcium hydroxide and magnesium hydroxide, etc.; organic acids such as acetic acid and formic acid, etc.; and salts of organic acids such as sodium acetate, calcium acetate, sodium formate and calcium formate. etc.; these compounds may be used in the form of single or mixed solids, liquids, aqueous solutions or solutions in water-soluble organic solvents. Or solids may be added in slurry state bY dispersing them in organic solvents in which they are hardly soluble but which are water-soluble.
The method of this invention is described hereunder:
~;~97618 First, polymer latex is filled in a tank and a polymer latex's swir] is formed. This polymer latex's swirl has the function of rapidly dispersin~ and scattering in the tank the seed grains which serve as seeds in making growth of coagulated grains.
Usable as an equipment for producing a polymer latex's swirl is one which forms a swirl by discharging latex in tangential direction to a stirring tank provided with no baffle plate or a cyclone type conical tank. And equipment usable as a stirring impeller, when a stirring tank provided with no baffle plate is used. may include a disc turbine, fan turbine, Pfaudler type, Brumagin type, propeller and H-type impellers, etc.; however, care is necessary with those which have discs like the disc turbines, for coagulated grains which have formed will sometimes deposit on their discs. And when inclined blades or a propeller impeller is used, and if the ~tirring is done in the up-flow direction, coagulated grains will recirculate in the vicinity of the latex swirl surface, so that they come in contact with the latex filmy downflow liquid, thus tending to form united coagalated grains, which is undesirable. The degree of turbulence of the polymer latex swirl may be set with the impeller Reynolds number d~ n/ v (d: impeller diameter, n:
number of revolution and v kinetic viscosity) as a guide, the range from 5 X103 to S X10~ being preferable. If its value is less than 5 x103, the coagulated grains which have formed tend to~settle and~deposit on the tank bottom; thus, they unite with eich oth~er, causing their discharge port to be blockaded. But if the stirring conditions are such that its value is larger , ~ .
~297618 than 5 x 1~, there will occur such a phenomenon as breakdown of the coagulated grains caused by the mixing impeller or pelling off of the coagulated grains surfaces due to mutual collision of coagulated grains ùnder violent flowing state, which is undesirable; if the breakdown of coagulated grains or the peeling of coagulated grains surfaces lasts long, the coagulant to be contained in each coagulated grain will go out of it, to be dissolved into the polymer latex, finally coagulating the whole of the polymer latex in the tank, thus making the formation of coagulated grains impossible.
~ hen, onto the aforementioned polymer latex swirl, the same polymer latex is caused to flow down in a liquid film state.
The polymer latex film flowing-down liquid containing coagulated matters formed by the addition of a coagulant into the flowing-down liquid falls down into the polymer latex swirl; it has functions of not only fractionalizing the coagulated matters formed in the flowing-down liquid into fine s~ed particles by means of its falling energy but also submerging the seed particles which tend to float under influence of surface tension. The liquid film forming method comprises letting polymer latex flow along a gutter~ or plate and, then, letting the polymer latex fall down from an end of the gutter or plate, thereby forming a filmy liquid. The filmy flowing-down liquid may be produced by discharging polymer latex liquid through a rectangular discharge port or a perforated tube with holes arranged at such a pitch that the discharged polymer latex flows will be immediately united. The ~, , . .
flow-down length of the liquid fiIm is desirably not more than 2 m from the surface of the Polymer latex swirl. If the flow--down length is in excess of 2 m, the amount of air entrained in the flowing-down liquid increases, resulting in violent foaming on the tank liquid surface; therefore, addition of an antifoaming agent, etc., should be contemplated. And the flow-down direction of the polymer latex filmy flowing-down liquid is desirably the same direction as that of the latex swirl; and further, the contacting points between the filmy flowing-down liquid and the latex swirl liquid surface is desirably radial from the tank center. If the flow-down direction is reversed, the latex swirl flow speed will decrease, undesirably leading to increased power consumption of mixing impeller.
Then, a coagulant is added to the filmy flowing-down liquid. If the coagulant is liquid, the addition of the Goagulant may be made by injection through such a spray nozzle as single port nozzle, full cone nozzle, etc., or vibrated nozzle or perforated tube, etc. The bore size of the nozzle or the perforated tube is desirably not more than 3 mm in diameter; if bores larger than this are used, the diameter of the coagulated grains formed will become extremely large, the grain size distribution will be expanded and this will undesirably cause formation of amorphous coagulated grains, not spherical grains. And proper discharge pressure of liquid coagulant should be on such an order that the coagulant does not break through the polymer latex liquid film. If the coagulant pierces the polymer latex liquid film, it causes formation of :....,:...,. -large mass of coa~ulated matters, when it falls down into theswirl liquid surfac e: if the coagu]ant wets the tank wal]
surface, it will fall down along the wall surface, causing the latex to flocculate at the position of latex level, thereby undesirably yielding scale. On the other hand, if the coagulant is solid, powders, granules, crystals, etc., may be quantitatively added by such powder supplying means as belt feeder, screw feeder, roll feeder and vibrating feeder, etc. As for where the coagulant is to be added into the polymer latex filmy flowing-down liquid, it may be added into the flowing-down liquid at whatever position, but desirably, the area spreads in a direction at a right angle to the liquid flowing-down direction. If the adding direction is the same as its flowing down direction, the once coagulated matters will further come in contact with the coagulant, resulting in uneven coagulant concentrations in the coagulated matters, thus facilitating formation of amorphous coagulated grains. In contrast, when the coagulant is added by spreading it at a right angle to the liquid's flowing down direction, the once coagulated matters will go flowing down, without making contact with coagulant again, thus enabling the coagulant concentrations in the coagulated matters to be uniform.
The coagulated matters formed in the flowing down liquid falls down into the latex swirl together with the flowing-down liquid and by its energy, they will be fractionalized to be :
dispersed as coagulated grains. In each of these fine coagulated grains, there is contained a high concentration of , I
,., `
coagulant; while they are staying in the tank for a specified time period, the coagulant will gradually come out, to pile coagulated layers one upon another, thereby getting the coagulated grains go on growing. The fine coagulated grains which have fallen to he fractionalized provide seeds for growing coagulated grains. If the coagulated matters which have fallen together with the flowing-down liquid have been fractionalized and are staying in the neighborhood of the place where they have fallen, other coagulated matters will fall down thereon one after another, thus, tending to form massive coagulated matters and united grains. To forestall this, the latex swirl quick]y carries off the fractionali~ed fine grains from the fall-down position of the latex filmy flowing-down liquid, to get them diffùsed and scattered, without allowin8 the fine grains containing high concentrations of coa8ulant to be united. When the concentration of the coagulated grains formed is desired to be increased, it is proper to increase the amount of the coagulant added, but as the addition is increased, the increase of the discharge pressure from the nozzle and the concentration of the fine grains containing high concentrations of coagulant near the liquid's falling-in position will become excessive; accordingly, the increase in the formation of massive coagulated matters and the united grains formation frequency is limited and as a countermeasure~ it i9 effective to let flow down the flowing-down liquid at two or three or other plural numbers of~positions.
In the fine grains containing high concentrations of ~: :
. . ,~,.......
coagulant which have been dispersed in the polymer latex swirl, the coagulant existing at the center of each of said grains will move by diffusion to the grain surface, while they are staying in the tank, to have the latex particles coa~ulated and laminated on the grain surfaces: as a result, the coagulated grains will grow larger. ~t this time, the coagulated grains will become nearly spherical coagulated grains closely and regularly packed with polymer latex particles.
The coagulated grains which have grown, while staying for a specified time period in a tank having the polymer latex swirl, are discharged from inside the tank. As the discharging method, a scooping method with a basket or a method of drawing them out as a mixed flow of the coagulated grains and the polymer latex, etc., may be used, but as the coagu]ated grains grow, they tend to sett}e and, therefore, the method of discharging from the tank bottom as their mixed flow with polymer latex is preferable. The coagulated grains formed are discharged, together bi th polymer latex. and only the coagulated grains formed may be taken out by means of such a solid-liquid separating means as an inclined screen separator, vibratory screen separator, etc. On the other hand, the polymer latex separated from the coagulated grains formed is again returned to the tank, to be used as the polymer latex filmy f}owing down llquid.
ccording to this invention, the teMperature of the i po}ymer latex and that of the latex swir]ing and residing in a tank needs to be a temperature lower than its softening . ~,~' .....
1Z~7618 temperature. ~he softening temperature as used here means a temperature at which the latex particles mutually fuse together under atmospheric pressure; generally, it is considered to be the melting point of a substance. However, since definite melting points can not be defined for polymers, they are hardly definable. Even the same polymer's melting point will not be determined by the polymerization degree or its distrihution only, but will be largely influenced by its crystalinity or additives which provide plasticizing effect. However, actually, it is reasonably considered to fall within the range of ~ ( (Tg ~273) / 0.8~ -273 ~ ( (Tg +273) / 0.6, - 273 ~ c, assuming that the glass transition point is Tg (C).
If the coagulated grains are formed in the state of being held at a temperature higher than their softening temperature, the polymer latex particles, being the basic particles, wil}
mutually unite with each other by fusion, giving rise to dispersions in the size and the sphericity of the united grains;
accordingly, they could not be coagulated grains having polymer latex particles fully packed therein in regular arrangement ;, ~ Affordingly, the temperature of the polymer latex ~hen forming , ~ ~
~ ; coagulated grains needs to be lower than its softening m ~ temperature.
In the following. this invention will be described in conjunction with the accompanying drawing:
FIG. 1 is a schematic diagram illustrating an apparatus for use in exercising the method of this invention: Numeral 1 designates a tank for forming a polymer latex swirl; after " ~
.
12976`J 8 filling the tank wi~h polymer latex, a mixing impeller 3 is turned by means of a stirrer driv;ng motor 2, thereby producing a polymer latex swirl in the tank 1. On the other hand, the po]ymer latex is led to the filmy flowing down liquid forming channel 4 through a liquid film forming polymer latex feeding line 13; thereafter, the polymer latex is callsed to flow down from an end of said channel ~, thereby forming a filmy flowing-down liquid 5. Into this flowing-down ]iquid 5, a coagulant is discharged from a coagulant storage tank 8 through a spray nozzle 6, using a coagulant adding pump 7. The coagulated matters formed in the flowing down liquid 5 fall down into the polymer latex swirl liquid surface, to be fractionalized and diffused and scattered in the tank. The coagulated grains which have grown while staying in said tank for a specified time period are discharged together with the polymer latex from the tank bottom through a line 9; then, the mixture is separated into coagulated grains and polymer latex in a solid-liquid separating means like a vibratory screen separator 10 and the coagulated grains thus formed are taken out through another line 11. And the polymer latex after this solid-liquid separation :~ is recycled by means of a liquid fiIm forming latex feeding pump 12, to be reused as the polymer latex filmy flowing-down liquid.
;When forming coagulated grains bY the method and the apparatus of this invention, the coagulated matters which are ~::
formed by adding a coagulant into the polymer latex filmy flowing down liquid are fractionalized by the energy of the : 1 7 ... ,.~,, , - .
.
~ ' . ' .
flowing down liquid, as it is falling into the latex sw;rl, to be fine coagulated grains containing high concentrations of coagulant. At this time, in the fractionalization of coagulated ~atters, the si7,e of the fine coagulated grains containing high concentrations of coagulant may be freely controlled by adjusting the leve] from which the flowing down liquid is caused to fall or the coagulant adding position, depending on the hardness of the coagulated matters, so that not only the formation of massive coagulated matters may be thwarted, but the grain diameter of the coagulated grains thus formed may be adjusted to any arbitrary size. And the fine coagulated grains containing high concentrations of coagulant will be sunk into the latex swirl by the flowing-down liquid;
accordingly, fine coagulated grains containing high concentrations of coagulant will not float on the latex level under the influence of the surface tension, thus foreclosing formation of united grains or amorphous grains. ~urther, the fractionalized fine coagulated grains containing high :
concentrations of coagulant are rapidly shifted due to the polymer latex swirl from the position where the latex flowing~
down liquid has fallen down, so that they go on growing, while flowing along the latex swirl stream line. Accordingly, the coagulated grains while in growth rarely meet and unite with coagulated grains containing high concentrations of coagulant;
thus, this system is quite effective in thwarting formation of massive coaeulated matters and united grains.
As herea~ove described, the present invention enables ,, . ::
, 1~97~i8 controlling the si,e of coagulated grains and thwarting formation of united grains, there~y effect;ng prevention of blockading of discharge port caused by massive coagulated matters or united grains and permitting for a long time stable growth of coagula~ed grains by way of continuous operation.
Since, according to this invention, the latex swirl is always flowing along the tank wall surface, the coagulated grains are running hi thout sticking on the tank wall surface.
Accordingly, this process is entirely free of scaling problem resulting from deposition of coagulated grains on the tank wall surface.
This invention permits spherical grains having arbitrary mean grain diameters to be taken out at the solid-liquid separation time, with a result that generation of fine powders after the drying process which was a disadvantage in the previous method is eliminàted, that powder handling ;s facilitated and that an environment free of dust is realizable at the processing time with these grains, and such other great merits are expectable.
Since, when continuous operation is run, the coagulated grains are taken out of the system by way of solid-liquid separation and will never again return to the tank, the mean coagulated grains forming time is equal to the mean residence time V/F (min), assuming the amount of polymer latex discharged through the polymer latex tank bottom to be F (kg/min), and the amount of the polymer latex in the tank V (kg). ~ccordingly, the coagulated grains forming time will be subiect to control by ~ : ~
~: :
~;: 1 9 ,, .
~297618 operationally adjusting the aforementioned mean residence time, so that adjustment of grain diameter may be made easily, thereby to form coagulated grains with a uniform grain size.
The coagulated grains' mean residence time in the continuous operation preferably fall i-n the range of 2-10 min.
In the fo]lowing, explanations are taken in connect;on with Examples of this invention and a Compal^ison Example, but it will never be restricted thereby.
, .. ~ . . . .
~97618 Example 1 ~ 30 cm inside diameter stirring tank having no baffle plate was filled with 42 kg of polymer latex with solid content of 30 % and held at a temperature of 25 C being a polymer latex having mixed together 33 % cf polymer latex (A) being a polymer latex formed by graft-copolymerizing on butadiene polymer a mixture of styrene, acrylonitrile and methyl methacrylate and consisting of 60 % butadiene, 10 % of methyl methacrylate. 10 %
of acrylonitrile and 20 % of styrene, and 67 % of homocopolymer latex (B) consisting of 20 % of ~-methyl styrene, 25 % of acrylonitrile and 55 % of styrene; then, the latex in the tank was stirred in down-flow direction with three bladed propeller type impeller of 20 cm diameter at 200 rpm, thereby forming a polymer latex swirl. Then the polymer latex was discharged through the tank bottom at a flow rate of 10.5 kg/min, to be again let fall down from an 8 cm wide channel into the latex swirl as a polymer latex filmy flowing-down liquid. At this ~ time, the height from the end of the channel to the latex swirl j level was set at 25 cm. ~hereafter, as a coagulant, 30 %
aqueous solution of calcium chloride was sprayed at 38 ml/min through two 0.6 mm~ single hole nozzles, using a peristaltic feeding pump, to be added into the polymer latex filmy flowing-- down liquid. Through the tank bottom, a mixed floh of the coagulated grains formed and the polymer latex was discharged at ; 10.5 kg/min; then, as it was subjected to solid-liquid -1 separation by the use of a 20 mesh vibratory screen separator, ~ the amount of the coagulated grains only discharged became ; , ; '' ~: ':
.
~ ; 2 1 12~7618 nearly constant 20 min after starting the continuous operation, enabling coagulated grains to be formed at a rate of approx. 2.1 kg per minute. For the amo~nt of polymer latex after subjected to the solid-liquid separation which was reduced by the coa~ulated grain formation, new polymer latex was replenished and this latex was recycled into the tank at a flow rate of 10.
5 kg/min. Accordingly, the mean residence time in this continuous operation was 4 min.
~ hen grain diameter measurement and shape observation of the coagulated grains formed after running continuous operation for 60 min was made, the coagulated grains formed were found to be nearly spherical grains with a uniform grain si2e of 4.4 mm mean grain diameter and no united grains grown by mutual unification of grains ~ere observed.
example 2 After forming a polymer latex swirl under the same stirring conditions, using the same polymer latex and apparatus, as in Example 1, the polymer latex was discharged through the tank bottom at a flow rate of 18 kg/min. Of the latex thus discharged, 10.5 kg/min was let fall down as the polymer latex filmy flowing-down liquid through the same channel as that of Example 1, while the remaining polymer latex was recycled into the tank with another pump. Thereafter, a coagulant was added to the flowing down liquid, using the same apparatus and conditions as in xample 1, thereby forming coagulated grains.
Through the tank bottom, an 18 kg/min mixed flow of the oagulated grains formed and the polymer latex was discharged : ~ :
~ 2 2 anA subjected to sol;d-liquid separation using a 20 mesh vibratory screen separator, whereby 20 min later, coagulated grains were obtained at a rate of approx. 2.0 kg/min. Recycling into the tank was done at a rate of 10.5 kg/min for liquid film formation and 7.5 kg/min directly into the tank, totallin~ 18 kg/min, while supplementing new polymer latex to the separated latex after the solid-liquid separation; accordingly, the mean -residence time in this continuous operation was 2.3 min.
The sample of the coagulated grains formed 60 min later were nearly spherical grains with a uniform grain size 3.2 mm mean grain diameter and almost no united grains were observed.
Examples 1 and 2 clearly suggest that the grain diameter of the coagulated grains formed may be adjusted by altering the mean residence time in the contin uous operation.
example 3 A swirl of polymer latex was formed under the same stirring condition, using the same polymer latex and apparatus, as in Example 1. Then, the polymer latex was discharged through the tank bottom at a flow rate of 10.5 kg/min, to be let flow down into the latex swirl as the polymer latex filmy flowing down liquid. Thereafter, as a coagulant. calcium chloride anhydride grains (grains sifted beforehand which passed 28 mesh.
but retained on 32 mesh screen) were added into the polymer latex filmy flowing-down liquid at a rate of approx. 12.5 g/min b~y a vibrating powder feeder. As a mixed liquid of the coagulated grains formed and the polymer latex was discharged at lZ97618 10~5 kg~min lhrou~h the tank bottom and subjected to solid-liquid separation using a 20 mesh vibratory screen separator, the amount of the coagulated grains only discharged became n,early constant approx. 20 min after starting the continuous operation, enabling the coagulated grains to be formed at a rate of 2.0 kg/min. ~s the grain diameter measurement and shape observation of the coagulated grains was made after 60 min continuous operation while seplenishing fresh polymer latex, the coagulated grains formed were found to be nearly spherical grains with a uniform grain size of 3.8 mm average grain diameter and mutual unification of grains was barely observed.
Example 4 ~ latex swirl was formed under the same stirring condition using the same apparatus, as in Example 1, while holding at 70'c polystyrene latex with solid content of 14 %
which was ohtained by polymerization of styrene monomer only, without using an emulsifier but with ammonium persulfate as a polymerization initator. Then the latex was discharged through the tank bottom at a flow rate of 8.4 kg/min and let fall down into the latex swirl as the latex filmy flowing-down liquid.
Thereafter, the same calcium chloride anhydride as that of Example 3 was added into the filmy flowing-down liquid at a rate of approx. 12.5 g/min by a vibrating powder feeder. Through the tank bottom, a mixed flow of the coagulated grains formed and the polystyrene latex was discharged at 8.4 kg/min: then, as this mixed flow was subjected to solid-liquid separation, using a 20 mesh vibratory screen separator, the amount of the ::
~ s 2 4 ;~ ~
coagulated grains only dischar~ed became nearly constant approx~
20 min after starting the continuous operation, thereby enabling the coagulated grains to be formed at a rate of 1.9 kg/min. As the grain diameter measurement and shape observation of coagulated grains were made, after continuing the operation for 60 min while supplementing polystyrene latex, the coagulated grains formed were found to be nearly spherical grains with a uniform grain size of 3.3 mm average grain diameter.
Comparative Example 1 A 40 Q stirring tank equipped with four baffle plates was filled with 25 kg of the same polymer latex as that of Example 1 and its content was stirred at 200 rpm with 10 cm diameter flat 4 blade turbine impeller. Thereafter, as a coagulant, 30 % aqueous solution of calcium ch]oride was added into the polymer latex liquid surface through a 4 mm~ ID tube at 23 ml/min, using a constant rate pump. From 5 min after starting the addition of coagulant, a mixed flow of the coagulated grains and the polymer latex was drawn out of the tank at a discharge rate of 6.5 kg/min and subjected to solid-liquid separation, using a 20 mesh vibratory screen separator, and the polymer latex was recycled inside the tank at a flow rate of 6.5 kg/min with supplementation of new polymer latex.
When~continuous operation was run under this condition, massive coagulated grains and amorphous coagulated grains were formed in large amounts and even though a 40 mm ~ piping was used for the discharge port, the mixed flow discharge of the coagulated grains and the polymer latex was not smooth, with the discharge ...... .
- ;
l~q6~8 port blockaded 35 min after starting the operation, resulting in shutdown of the operation, As the inside of the tank was observed after the shutdown, a large amount of scale was found to have grown and been sticking on the baffle plates and tank wall liquid surface.
.
: 2 6
Claims (10)
1. A method of manufacturing coagulated grains from polymer latex characterized in that a swirl is produced of polymer latex in a tank, while holding the polymer latex particles at a temperature lower than the softening temperature at which the latex particles adhere to each other by fusion;
while the same polymer latex as said polymer latex is caused to flow down into the aforementioned swirl liquid surface at a temperature lower than the aforementioned softening temperature, a coagulant is dispersed and scattered into the latex in the tank by adding said coagulant into said latex flowing-down liquid; thereafter, with said coagulant thus scattered as seeds, coagulated layers are grown on their outer surfaces, whereby nearly spherical coagulated grains with a uniform grain size are obtained, while inhibiting formation of massive coagulated matters.
while the same polymer latex as said polymer latex is caused to flow down into the aforementioned swirl liquid surface at a temperature lower than the aforementioned softening temperature, a coagulant is dispersed and scattered into the latex in the tank by adding said coagulant into said latex flowing-down liquid; thereafter, with said coagulant thus scattered as seeds, coagulated layers are grown on their outer surfaces, whereby nearly spherical coagulated grains with a uniform grain size are obtained, while inhibiting formation of massive coagulated matters.
2. The method according to Claim 1. wherein the continuous operation is conducted in such a way that the weight of the coagulated grains which have been taken out and the weight of fresh polymer latex supplemented to the tank are to be nearly equal.
3. The method according to Claim 2. wherein the mean residence time of the coagulated grains in the tank in the continuous operation is set from 2 to 10 min.
4. The method according to Claim 1, wherein the coagulant is an aqueous solution of inorganic salt or inorganic acid.
5. The method according to Claim 1, wherein a degree of turbulence of the latex swirl is within a condition range of from 5 x 103 to 5x 104 in the impeller Reynolds numbers.
6. An apparatus for manufacturing from polymer latex nearly spherical coagulated grains with a uniform grain size, which is comprised of a tank for holding polymer latex, equipment for forming a swirl of latex in said tank, equipment for letting said polymer latex fall down into said latex swirl liquid surface and equipment for adding a coagulant into said polymer latex flowing down liquid.
7. The apparatus according to Claim 6, wherein the tank for holding the polymer latex and the equipment for producing a latex swirl in said tank comprise a stirring tank.
8. The apparatus according to Claim 6, wherein the equipment for letting the polymer latex fall down is installed within 2 m of the latex swirl liquid surface.
9. The apparatus according to Claim 6, wherein the equipment for adding the coagulant is designed for adding an aqueous solution of coagulant through a nozzle.
10. The apparatus according to Claim 9, wherein the bore of the nozzle through which the aqueous solution of coagulant is added is not more than 3 mm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62098088A JPS63264636A (en) | 1987-04-21 | 1987-04-21 | Process and apparatus for producing coagulated particle from polymer latex |
| JP98088/87 | 1987-04-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1297618C true CA1297618C (en) | 1992-03-17 |
Family
ID=14210588
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000564558A Expired - Fee Related CA1297618C (en) | 1987-04-21 | 1988-04-20 | Method and apparatus for manufacturing coagulated grains from polymerlatex |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4890929A (en) |
| EP (1) | EP0288018B1 (en) |
| JP (1) | JPS63264636A (en) |
| CA (1) | CA1297618C (en) |
| DE (1) | DE3886805T2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5921679A (en) * | 1995-09-25 | 1999-07-13 | Rutgers, The State University Of New Jersey | Method of chaotic mixing and improved stirred tank reactors |
| FR2749310B1 (en) * | 1996-06-03 | 1998-08-14 | Atochem Elf Sa | PROCESS FOR PRODUCING COAGULATED POLYMER LATEX PARTICLES |
| TWI378110B (en) * | 2004-09-15 | 2012-12-01 | Kaneka Corp | Method for producing suspension, solution or dispersion |
| US20060093536A1 (en) * | 2004-11-02 | 2006-05-04 | Selby Daniel R | System and method for mixing a slurry |
| WO2014196707A1 (en) * | 2013-06-03 | 2014-12-11 | (주) 엘지화학 | Device for manufacturing polymer latex resin powder and method for manufacturing polymer latex resin powder using same |
| KR101594652B1 (en) | 2013-06-03 | 2016-02-16 | 주식회사 엘지화학 | Apparatus for preparing polymer latex resin powder and manufacturing method of polymer latex resin powder using the same |
| CN108713365A (en) * | 2016-05-31 | 2018-10-30 | 肖剑 | A kind of Geldart-D particle applied to restoration of the ecosystem feeds pulsating seed priming device |
| CN112142881A (en) * | 2020-10-21 | 2020-12-29 | 辽宁宝来新材料有限公司 | ABS graft latex coagulating method and device thereof |
| WO2023126162A1 (en) | 2021-12-27 | 2023-07-06 | Sabic Global Technologies B.V. | Method and system for manufacture of particulate polymers |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1656990A (en) * | 1924-06-14 | 1928-01-24 | Petroleum Sand Products Corp | Process of refining oils |
| DE1128125B (en) * | 1956-05-11 | 1962-04-19 | Bayer Ag | Process and device for producing porous or homogeneous plastic semi-finished products or finished articles based on polyurethane |
| US3068167A (en) * | 1959-11-16 | 1962-12-11 | Cities Service Res & Dev Co | Screen separation of tar sand |
| US3425667A (en) * | 1967-03-31 | 1969-02-04 | Inst Lacke & Farben | Method and apparatus for making paints |
| US3993292A (en) * | 1974-12-13 | 1976-11-23 | W Bar E, Incorporated | Apparatus for coagulating polymer latex emulsions |
| US4110491A (en) * | 1976-06-29 | 1978-08-29 | E. I. Du Pont De Nemours And Company | Method and apparatus for encapsulating and coagulating elastomers |
| US4107793A (en) * | 1977-05-26 | 1978-08-15 | Monsanto Company | Mixer apparatus for continuously coagulating an aqueous latex and consolidating as a paste coagulum |
| US4259022A (en) * | 1979-12-10 | 1981-03-31 | Folland Corporation | Fuel producing system for solid/liquid mixtures |
| US4336328A (en) * | 1981-06-11 | 1982-06-22 | Eastman Kodak Company | Silver halide precipitation process with deletion of materials through the reaction vessel |
| JPS5887102A (en) * | 1981-11-19 | 1983-05-24 | Kanegafuchi Chem Ind Co Ltd | Process and apparatus for producing coagulated latex |
| DE3502153A1 (en) * | 1985-01-23 | 1986-07-24 | Röben Kolloid Entwicklung GmbH & Co KG, 2932 Zetel | COLLOIDATOR FOR THE COLLOIDATION OF FLOWABLE MATERIALS |
-
1987
- 1987-04-21 JP JP62098088A patent/JPS63264636A/en active Granted
-
1988
- 1988-04-20 DE DE3886805T patent/DE3886805T2/en not_active Expired - Fee Related
- 1988-04-20 EP EP88106254A patent/EP0288018B1/en not_active Expired - Lifetime
- 1988-04-20 CA CA000564558A patent/CA1297618C/en not_active Expired - Fee Related
- 1988-04-20 US US07/183,811 patent/US4890929A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE3886805D1 (en) | 1994-02-17 |
| JPH0580937B2 (en) | 1993-11-10 |
| EP0288018A3 (en) | 1990-01-17 |
| JPS63264636A (en) | 1988-11-01 |
| EP0288018A2 (en) | 1988-10-26 |
| EP0288018B1 (en) | 1994-01-05 |
| US4890929A (en) | 1990-01-02 |
| DE3886805T2 (en) | 1994-05-19 |
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