CA2058326C - Process for preparing fluid suspensions of polysaccharide mixtures - Google Patents
Process for preparing fluid suspensions of polysaccharide mixtures Download PDFInfo
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- CA2058326C CA2058326C CA002058326A CA2058326A CA2058326C CA 2058326 C CA2058326 C CA 2058326C CA 002058326 A CA002058326 A CA 002058326A CA 2058326 A CA2058326 A CA 2058326A CA 2058326 C CA2058326 C CA 2058326C
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- polysaccharide
- cmc
- hydroxyethylcellulose
- mps
- suspension
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H19/00—Coated paper; Coating material
- D21H19/36—Coatings with pigments
- D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
- D21H19/52—Cellulose; Derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D101/00—Coating compositions based on cellulose, modified cellulose, or cellulose derivatives
- C09D101/08—Cellulose derivatives
- C09D101/26—Cellulose ethers
- C09D101/28—Alkyl ethers
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H19/00—Coated paper; Coating material
- D21H19/10—Coatings without pigments
- D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
- D21H19/34—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising cellulose or derivatives thereof
Abstract
A nonionic cellulose ether such as hydroxyalkylcellulose, alkylcellulose or an alkylhydroxyalkylcellulose hydrophobically modified with a C4 to C24 alkyl or an arylalkyl group is suspended by a low molecular weight polysaccharide and below 10% by weight salt to provide a fluidized polymer~suspension. the process for manufacture involves preparing an aqueous polysaccharide solution and adding a nonionic cellulose ether while stirring.
Anionic, nonionic and cationic suspending polymers such as CMC, CM Guar, HEC and cationic starch may be used. Sodium carbonate is a preferred salt.
Anionic, nonionic and cationic suspending polymers such as CMC, CM Guar, HEC and cationic starch may be used. Sodium carbonate is a preferred salt.
Description
The invention relates to aqueous fluid suspensions of polymeric thickeners. In particular the invention relates to the use of fluidized suspensions of polysaccharide mixtures in paper coating compositions U.S. Patents 4,799,962, 4,883,536 and 4,883,537 disclose aqueous fluid mixtures and suspension containing polyethylene oxides or salts. U.S. Patent 4,154,899 describes the use of pigment, clay and modified starch ether for coating compositions which are applied to paper during manufacture.
European Patent Application EP 307-795 describes a pigment dispersion used for paper coating which can contain modified starch, galactomannan, methylcellulose (MC) or carboxymethylcellulose (CMC). A quaternary starch ether is employed in the papermaking method of U.S. Patent 4,840,705.
It is further known from Aqualon~ publication 250-11C, Natrosol~ - Hydroxyethylcellulose - A Nonionic Water-Soluble Polymer - Physical and Chemical Properties. that this cellulosic can be used in coating colors and size press solutions to control water binding, solids holdout and rheology. Hercules Incorporated product data publication 456-2, Natrosol~ in Pigmented Coatings for Paper. and Paperboard, contains viscosity data useful for selection of a grade of product fox a papermaking application.
U.S. Patents 4,228,277 and 4,243,802 describe hydrophobically modified hydroxyethylcellulose (HMHEC) fox use in latex paints and shampoos. Chain lengths from C4 to C24 can provide the hydrophobic modification.
Still it remained for the present invention to teach how two or more anionic and nonionic polysaccharides provide a fluid suspension applicable for paper manufacture.
_1_ It is an object of the invention to provide an aqueous fluidized polymer suspension comprising at least one low molecular weight polysaccharide and at least one nonionic cellulose ether polymer with a salt content below 10% by weight wherein the suspension remains fluid and pourable.
It is preferred for paper coatings that the nonionic cellulose ether polymer be a water soluble hydrophobically modified alkylcellulose, alkylhydroxyalkylcellulose or hydroxyalkylcellulose.
A process for preparing a fluidized polymer suspension involves the steps=
(1) Preparing an aqueous solution of a low molecular weight polysaccharide containing up to 10% by weight ammonium or alkali salt from the group of carbonate, sulfate, phosphate or formate~ and (2) stirring the solution while adding a nonionic cellulose ether to prepare a fluidized polymer suspension.
An anionic cellulose and hydrophobically modified cellulose ether mixture can be added as a sole thickening agent or be used in combination with other thickening agents for Paper coating compositions. Sodium carboxymethylcellulose is a preferred anionic polymer and hydrophobically modified hydroxyethylcellulose is a preferred nonionic cellulose ether polymer.
In another aspect the invention provides an aqueous paper coating composition of clay, calcium carbonate and/or gypsum, a binder selected from the group consisting of starch, protein and latex and thickener; characterized in that the thickener is a Multi-Polysaccharide Suspension (MPS) of dispersed particles of a nonionic hydrophobically modified cellulose ether selected from the group consisting of hydroxyethylcellulose, ethylhydroxyethylcellulose, methyl-cellulose, hydroxypropylcellulose, methylhydroxypropylcellulose and methyl hydroxyethylcellulose in a continuous aqueous phase of a dissolved polysaccharide selected from the group consisting of hydroxyethylcellulose, cationic starch, carboxymethylcellulose and carboxymethylguar wherein the polysaccharide is of sufficiently low molecular weight that a 15 weight percent solution will have a Hrookfield viscosity at 12 rpm at room temperature of 10,000 mPa.s or lower and the MPS
contains 10 percent by weight or less of a salt or salts from the group of sodium carbonate, potassium carbonate, sodium sulfate, diammonium phosphate and sodium formate and the MPS
contains a stabilizing amount of xanthan wherein the MPS
remains fluid and pourable.
This invention is concerned with fluid aqueous suspensions comprising at least two water-soluble polysaccharides that possess distinct properties. One of the polysaccharides in the Multi-Polysaccharide Suspension (MPS) is of a relatively low molecular weight (MW) and is dissolved in the continuous aqueous phase. One or more nonionic cellulosic polymers is present in a form of dispersed particles in the suspension. The suspension either contains no added salt or a relatively low level of inorganic salt or mixture thereof (less than 10 wt.%). The suspensions typically have a total polysaccharide concentration of 20 wt.% or higher and are -2a-Yj ':.~ i..: '':% i~' ~',.~
fluid and pourable. All of the Multi-Polysaccharide Suspensions (MPSs) described herein can be readily dispersed and dissolved in aqueous solvent.
The continuous aqueous phase of the MPS contains a dissolved low-MW polysaccharide, an inorganic salt at a concentration of 0 (salt-free) to 8 wt. % (low-salt), and rninor amounts of additives (less than 1 wt. %) which may include defoamer, dispersant, preservative, and/or suspension stabilizers such as xanthan gum. These dissolved low-MW
polysaccharide can be a CMC (anionic, e.g., Ambergum~ 1570 or Ambergum~ 3021), a hydroxyethylcellulose HEC) (nonionic, e,g., AQU-D3097), a degraded carboxymethyl guar (anionic, e.g., AQU-D3144), all of which are available from the Aqualon Company, and a starch derivative (cationic starch such as Amaizo~ 2187). These dissolved low-MW polysaccharides generally have a solution viscosity of less than 10,000 mPa.s as measured at a concentration of 15 wt. % using a Brookfield viscometer at 12 rpm. The inorganic salt (or salt mixture) for use in the preparation of the referred suspensions may be sodium formate, sodium carbonate, sodium sulfate, potassium carbonate, diammonium phosphate, or others.
The dispersed phase contains one or more Dispersed, Nonionic Cellulosic Polymer (DNCP). The DNCP can be a hydroxypropylceilulose (e.g., Klucel~ HPC), methylcellulose or methylhydroxypropylcellulose (e. g., CulminalT~ MC or Benecelr"
MHEC), hydrophobically modified hydroxyethylcellulose (e. g., Natrosol~ Plus 330 HMHEC), or hydroxyethylcellulose (e. g., Natrosol~ .HEC). Insolubilization of the DNCP, which is less hydrophilic than the dissolved polysaccharide, is primarily a result of the difference in water solubility between the dissolved polysaccharide and the DNCP. Further reduction in DNCP swelling or dissolution, where necessary, may be attained by dissolving in the aqueous phase a relatively small amount of salt, which helps reduce the amount of water accessible to the DNCP. the dissolved polysaccharide also causes an increase in the liquid phase viscosity, which reduces the rate of .. fir, ,'a ~ x.1. in 4c1 ~~i% '.:I ~, ~; n.7 i~~' ~, l settlement of the suspended polymer particles and, hence, improves suspension stability.
A MPS can be prepared by adding a DNCP to a vigorously agitated solution of the low-MW polysaccharide in which an amount of inorganic salt (or salts) at a concentration of 0 to g wt. % has been previously added. A fluid suspension is obtained after the mixture is stirred for a period of 15 to 60 minutes. A small amount of additives such as defoamer, dispersant, or suspension stabilizer may be added if necessary. Additives such as defoamer may be added before or after the DNCP has been dispersed into the aqueous solution.
The suspensions can be readily pumped and redissolved in aqueous media; the dissolution of the suspension is substantially faster than that of the nonionic cellulosic polymer. These properties can lead to a significant improvement in the efficiency of polymer solution makeup operations, and reduce or eliminate difficulties often associated with handling of dry powders of cellulosic polymers, such as powder dusting and lumping of wet particles during mixing.
This invention is intended to introduce (1) a new methodology of preparing easily processable suspensions of cellulosic polymers that contain a relatively low level of added salt, and (Z) a means to produce uniform mixtures of cellulosic polymers which can provide different functionalities in a certain application.
The MPSs are of use in various applications where one of the following conditions exist:
(a) Each of the different polysaccharides in the suspension imparts essential functionality to the end application.
(b) The DD1CP (suspended polymer) is primarily responsible for the key functionality; the dissolved polysaccharide allows (1) suspending of the functional DNCP without using a high level of salt (high salt level not tolerated in concerned 1~ ~:'~ t'?, fa ~' ',:~ ~..1 application); (2) fast and ready dissolution of the suspended polymer; and/or (3) other desirable properties that are not critical to the end application, such as added thickening/water holding or improved particle dispersion (as protective colloid in the end formulation).
2n common with other industries, the paper and paperboard manufacturers seek to improve productivity and lower mill cost. One of the problems limiting their productivity has been the necessity to employ solid thickeners in preparing suitable coating compositions.
Ideally. a paper coating thickener/co-binder should bring about desired rheological properties that allow easy mixing, pumping and recycling, and, most importantly, proper metering of the pigrnented coating. It should also lead to a coating structure which is less prone to water loss when i.n contact with paper. web during the coating operation. A
suitable combination of. coating rheology and water retention capability then leads to well--controlled coat weight and good coater runnability. An ideal thickener/co-binder should also impact the coating structure in such a way that coated paper properties such as gloss, opacity, and coating strength may be enhanced. Moreover, there is an increasing need for thickeners/co-binders in a fluid liquid form to facilitate rapid, automated coating preparation in today's high speed coating operations.
Cellulosic derivatives such as CMCs have been known for years to be effective as paper coating thickeners. As derivatives of cellulose, they have inherent affinity towards the paper substrate upon which the pigmented coating is placed. This nature, together with their water binding property and long chain structure, is largely responsible for their effectiveness as thickeners/co-binders. However, the ever increasing demands for increased coating speed and enhanced coating properties call for new products that can simultaneously provide several different but essential G1 I,"_~ C) ~'3 ~? ? ~
i. ~ ~ .; D : ~i -i ~;J ;.~ '..l functions. These demands sometimes cannot be satisfied with one single cellulosic polymer, and a product consisting of more than one cellulosic derivative, such as MPS, is needed. The following illustrates how the MPSs HMHEC/CMC and HMHEC/MC/CMC
suspensions meet the current needs f_or liquid products and various essential coating properties.
The inclusion of more than one cellulosic polymer with distinct properties in the suspension makes it possible to attain a combination of desirable coating properties that are not readily obtainable from a single polymer. For instance, a HMHEC has been shown to give a combination of strong low-shear coating structure, which helps reduce penetration of coating into the paper substrate, and low flow resistance under high shear conditions typical of blade metering at high coating speeds. It also gives generally high thickening efficiency, which means only a relatively low dosage is required to thicken the coating to a certain target viscosity, lay virtue of its self-associating nature. These properties make the HMHEC an effective light-weight coating (LWC) for papers. However, when a HMHEC is used as the sole thickener/co-binder in a clay-containing coating formulation, its highly clay adsorbing nature often results in a relatively low aqueous liquid viscosity, and hence a somewhat limited water retention capability (indicated by a relatively short water retention time for the coating). Improvement in water retention capability may be achieved by using a MPS also consisting of a CMC.
Suspensions can be readily dispersed and dissolved in a large mass of aqueous liquid. Thus, they can be added to the pigmented coating at different stages of the mixing Process, making them adaptable to various coating preparation conditions. This nature makes the MPSs suitable for highly automated coating preparation processes.
It was a surprising result to find how efficient the composition and process of the invention were in meeting the aims of the paper industry. Uniform paper surfaces can be produced using a MPS as the thickener. Higher productivity can ~l,f.c)G)r7t~
a.~ ~ c~ ..:~ ~ .;
be achieved without sacrifice. of quality or significantly increasing costs using the low salt combination of anionic and nonionic cellulosic polymer.
Cellulosic thickening agents having suitable hydrophobic modification are available from the Aqualon Company. A
preferred modified cellulosic is Natrosol~ Plus HMHEC. An Aqualon publication, Natrosolo Plus 250-18A, describes how this material functions as an associative thickener in paint, but gives no suggestion of the present invention.
A suitable low molecular weight polysaccharide is carboxymethylcellulose (CMC), available from Aqualan Company as Ambergum~ 1570 or Ambergum~ 3021. However, the suspending polymer is not limited to anionic materials since low molecular weight nonionics such as hydroxyethylcellulose (HEC) or cationics, such as AmaizoO 2187 available from American Maize, may also be used in the practice of the invention.
The suspending polymer (low molecular weight polysaccharide), whether anionic, nonionic or cationic, must be available in a state such that a 15% by weight solution gives a Brookfield viscosity at room temperature below 10,000 mPa.s.
Depending upon the needs of the paper manufacturer, it may be desirable to use one or more hydrophobically modified cellulosics in combination with one or more anionic cellulosics such as CMC. Similarly other Low molecular weight polysaccharides, such as hydroxyethylcellulose (HEC), carboxymethylguar (CM Guar) or starch derivatives, can be used as the dispersing medium for other cellulosic polyrnexs such as methylcellulose (MC), methylhydroxyethylcellulose (MHEC), methylhydroxypropylcellulose (MHPC), hydroxypropylcellulose (HPC) or hydroxyethylcellulose (HEC).
Typical ingredients fox paper coating compositions in addition to thickeners include: pigments (e. g., kaolin clay, calcium carbonate, gypsum, titanium dioxide, etc.), polymeric binder (2.g., styrene-butadiene latex, protein, starch, etc.), lubricants such as glycols and fatty acids. insolubilizers and defoamers. Once prepared as a coating composition, it is usual _7_ a..
C v,"5 !n. ~~ r1 ~ ~ 1"~
~~ ~'u ~J .: _l :~u , practice in the industry to measure viscosity and rheology properties of the composition prior to an actual test of the composition. Tn this way a body of knowledge is built up by comparison of such results with the actual quality and S reproduceability provided by any of the compositions tested.
In addition to paper coating, it is possible to find uses for MPSs in the areas of latex paints, food, pharmaceutical, personal care, and others. In these applications the polysaccharides involved in the MPS are normally employed to provide viscosity, rheology control, water.
retention, and/or formulation stability. The low salt content of the invention can be highly desirable since adverse effects of salt on the colloid chemistry of the concerned formulation may be minimized. With little or no added salt in the polysaccharide suspension, health concerns due to salt content will be minimal. Thus a salt-free or low-salt MPS of HPC, MC, or MHPC can be used in food and personal care products.
Examples 1 to 8 describe the compositions and physical properties of various types of MPSs. Total polymer concentration of these MPSs range from 20 to 30 wt. %. The weight ratio of DNCP to dissolved polysaccharide ranges from about 2.1 to 0.5. The pH values vary from 6,2 to 10.7.
Brookfield viscosities measured at 6 rpm fall between 700 and 12,000 mPa.s (cps). Example 9 illustrates the use of MPS as thickeners/co-binders in paper coating formulations, Example 1 Salt-Free Suspension Containing HPC and CMC
This example illustrates the preparation of a fluid suspension of hydroxypropylcellulose (HPC) in a solution of sodium carboxymethylcellulose (CMC). The composition of this MPS is given in Table 1. It was prepared by adding the fine HPC powders into a vigorously agitated CMC solution, followed by continued mixing for approximately 30 minutes. Minor amounts of defoamer and suspension stabilizer (xanthan gum) were predissolved in the CMC solution before the addition of HPC powders.
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The resulting MPS was found to dissolve in aqueous media significantly faster than the corresponding dry HPC product.
The time required for the suspension to attain 90% of its equilibrium solution viscosity in cold water was ca. 7.0 minutes, compared to over one hour for the dry HPC. Since this composition does not contain any added salt, it may be used as thickener, binder, or Process aid in personal care, food, pharmaceutical, and other products, where a high level of salt can cause health concerns.
The low-MW CMC used in this example was supplied as a solution product which had a solutic>n viscosity of ca. 1000 mPa.s at a concentration of 15 wt. ~>. The Klucelo hydroxypropylcellulose (HPC) and the CMC solution product, with a trade name of Ambergum~ 1570, are both available from Aqualon. The defoamer, Hercules DF 285, is available from Hercules Incorporated. The xanthan gum was obtained from Kelco. All the suspension viscosities given in this and the following examples were measured using a Brookfield LVT
viscometer at a rotating speed of 6 rpm, and are reported in mPa.s (cps).
Table 1 Composition of Salt-Free MPS Containing Hydroxypropylcellulose and CMC
HPC, Klucel~ HXF 12.0 CMC. in Ambergumm 1570 12.0 Defoamer, Hercules DF 285 0.2 Xanthan Gum, Kelzan~ S 0.4 Methyl parasept (Preservative) 0.1 Water 75.3 pH 6.2 Viscosity 6100 Wt. % polysaccharide 24.4 _g_ 6"1 ,;.,. ,.~ S.7 ~., .i,:i J' y' ' ; r_) . ,, ~~ -~.'r s.::
Example 2 Suspending a HMHEC in a CMC Solution A MPS containing a hydrophobically-modified hydroxyethylcellulose (HMHEC) and a low-MW CMC was prepared as described in Example 1. An amount of inorganic salt at a level up to 7 wt. % Haas added to the composition to supplement the low-MW CMC in insolubilizing the HMHEC. Small amounts of defoamer and preservative (methyl parasept) ~rere also added to help maintain the suspension stability. The HMHEC and CMC used in this example are available from Aqualon Company.
The MPS was made by (1) preparing an aqueous solution which captained predetermined amounts of CMC and methyl parasept, (2) dissolving the salt in the aqueous solution, which took ca. 20 to 30 minutes, (3) gradually adding the dry HMHEC solids into the aqueous solution which was under vigorous agitation, and (4) adding the defoamer. The resulting suspension was then mixed for ca. 30 minutes to ensure uniform dispersion. Typical pH and Brookfield viscosity values for the suspensions are given in Table 2.
Table 2 Compositions of MPSs Containing HMHEC and Low-MW CMC
HMHEC, Natrosol~ Plus 330 10.0 14.0 10.0 10.0 CMC, in Ambergum~ 1570 10.0 6.0 10.0 10.0 Sodium carbonate 5.0 6.2 - -Sodium sulfate - - 7.0 Diammonium phosphate - - 7.0 Defoamer 285 0.2 0.2 0.2 0.2 Methyl parasept 0.1 0.1 0.1 0.1 Water 74.7 73.5 72.7 72.7 pH 10.3 10.1 6.9 7.6 Viscosity 8400 4000 9300 5400 Wt. % Polysaccharide 20.0 20.0 20.0 20.0 MPSs of this type have been shown to be useful in paper coating applications. The use of a HMHEC/CMC MPS as a paper coating thickener/co-binder is illustrated in Example 9.
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Example 3 Suspending a MC or MC Derivati ve in a CMC Solution This example describes the preparation of MPSs containing a low-MW CMC (as described in Example 1) anti a methylcellulose or a methylcellulosederivative such as methylhydroxypropylcellulose (MHPC) or methylhydroxyethylcellulose (MHEC).
Table 3 Compositions of MPSs Containing and MC, MHPC, or MHEC
CMC
MC, Culminal~ 400 10.0 - -MHPC, Benecel0 MP943W - - 11.0 MHEC, Culminal~ C3033 - 100 CMC, in Ambergumo 1570 10.0 10.0 11.0 Sodium carbonate 2.0 2.0 Sodium sulfate 3.5 Hercules DF 285 0.2 0.2 0.2 Xanthan Gum, Kelzan~ S 0.2 0.2 0.4 Methyl parasept 0.1 0.1 0.1 Water 77.5 77.5 73.8 pH 10.3 10.3 6.7 Viscosity 4900 5500 9100 Wt. % polysaccharide 20.2 20.2 22.4 These MPSs also demonstrated faster dissolution in aqueous media than the correspondingdry MC, MHEC, or MHPC.
For instance, the time required MPS 3-C (Table 3) to attain for 90 of its equilibrium viscosity less than five minutes, in was comparison to about 40 minutes he dry Benecel~ MHEC
for t product. With the relatively low salt contents, such MPSs may find commercial use in personal and paper coating care applications.
Example 4 HEC Suspended in CMC Solutions The following MPSs demonstrate the feasibility of preparing fluid suspensions that contain a hydroxyethylcellulose (HEC) and a low--MW CMC. The procedure P
~~ ~,~ ~j ,r~ ,,~ ,r;, ~~ ~,p l~ :~~ .., y-9 for preparing the MPSs is similar to that described in Example 1. A CMC with a very low MW, which gave a solution viscosity of about 1000 cps at a concentration of 30 wt. %, was used :in this example. This low MW CMC is available as a solution product (AmbergumC~ 3021) from Aqualon Company. The I-IEC
Products are also available from Aqualon, Table 4 MPSs Containing a Suspended HEC and Dissolved CMC
HEC, Natrosol~ 250 GR 10.0 - -HEC, NatrosolC~ 250 MXR 10.0 I-IEC, Natrosolo 250 HBR - - 1U.0 CMC, in Ambergum~ 3021 10.0 10.0 10.0 Sodium carbonate 5.0 -- -Diamrnonium phosphate - 4.0 5.0 Water 75.0 76.0 75.0 pH 10.0 7.1 7.4 Viscosity 2400 2200 2000 Wt. % polysaccharide 20.0 20.0 20.0 Example 5 HPC Suspended in HEC Solution This example describes the preparation of a MPS
containing a HPC and a low-MW HEC. Success in preparing such a MPS indicates that the dissolved polymer in a MPS does not have to be ionic in nature.
The procedure of preparation was the same as that described in Example 1. The HEC used had a solution viscosity of ca. 1000 cps at a polymer concentration of 30 wt. %. Both the HEC and HPC are available from Aqualon, ~S i" !,7 ~3 ~.~.~ ~.~:~ri::.~~'~:7 Table 5 Suspension of HPC in Solution of a Low-MP1 HEC
HPC, Klucelo HX~' 10.0 HEC, in AQU-D3097 20.0 Sodium carbonate 2.0 Methyl parasept 0.1 Water 67.9 PH 8.9 Viscosity, {mPa.s) 2400 Wt. % polysaccharide 30.0 Example 6 Two Nonionic Cellulosic Polymers Suspended in CMC Solution It is possible to have two nonionic cellulosic polymers suspended in a solution of a low-MW cellulosic polymer. The compositions shown in Table 6 are examples of such terpolymer MPSs. These compositions, in general, contained a HMHEC and a MC or MC derivative in the dispersed phase and a low-MW CMC
(such as Ambergumca 1570) in the aqueous phase. The procedure for the preparation of these suspensions was similar to 'that of Example i. The DNCPs were added to the aqueous CMC solution in sequence before the addition of the defoamer.
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Table 6 MPSs Containing Two DNCPs and Dissolved One Polymer HMHEC, Natrosol~ Plus 10.0 10.0 10.0 10.0 MC, Culminal~ 400* 5.0 - - -MHEC, Culminal~ C3033~ - 8.0 - -MHPC~ Culminalo 6000 PR - - 5.0 5.0 CMC~ in Ambergum~ 1570 7.0 7.0 7.0 7.0 Sodium carbonate 6.0 6.5 6.0 -Diammonium phosphate - - - 8.0 Hercules DF 285 0.3 0.3 0.3 0.3 Methyl Parasept 0.1 0.1 0.1 0.1 Water 71.6 68.2 71.6 69.6 pH 10.1 9.8 9.9 7.6 Viscosity 5800 116005300 5700 Wt. % Polysaccharide 22.0 25.0 22.0 22.0 *The dry polymer products were ground in the laboratory to give finer particles to reduce settling of the suspended particles.
Example 7 HMHEC Suspended in Low-MW Guar Derivative A depolymerized, low-MW guar derivative. a carboxymethylated guar (CM guar) in this example, has been used to suspend a HMHEC with the aid of 6 parts of sodium carbonate. This example manifests that the dissolved polymer is not necessarily limited to cellulosic derivatives.
The low-MW CM guar is available from Aqualon as a solution product (AQL~-D3144). At a CM guar concentration of 34 wt. %, this aqueous solution had a Brookfield viscosity of 220 cps.
Table 7 MPS Containing a Low--MW CM Guar as the Dissolved Polysaccharides HMI-IEC, Natrosol~ Plus 330 10.0 CM guar, in AQIJ-D3144 10.0 Sodium carbonate 6.0 Hercules DF 285 0.2 Methyl parasept 0.1 Water 73.7 pH 9.6 Viscosity 700 Wt. % polysaccharide 20.0 Example 8 HMHEC Suspended in Starch Solution This example describes the use of another non-cellulosic polysaccharide as the dissolved polymer, a low-MW, cationic starch manufactured by American Maize (AmaizoC~ 2187). To prepare this suspension, a stock solution of the cationic starch (a dry product) was first prepared using a steam cooker. Make-up water and the salt were added to the stock solution, followed by the addition of the DNCP, a HMHEC.
Table 8 HMHEC Suspended in Starch Solution HMHEC, Natrosol~ Plus 330 10.0 Cationic starch, Amaizo~ 2187 14.3 Sodium carbonate 4.3 Methyl parasept 0.1 Water 71.3 pH 9.9 Viscosity 4200 Wt. % polysaccharide 24.3 _ 15 --Example 9 Use of MPSs as Thickener/Ca-Dinder.s for Paper Coatings This example demonstrates the use of two types of MPSs as thickeners/co-binders in paper coating formulating. One type of MPS contains HMHEC and CMC. The other contains HMHEC, CMC and MHEC.
HMHEC/CMC NIPS
Associative thickeners (i.e., hydrophobically modified cellulose ethers which associate with themselves) are useful in the practice of the present invention, providing improved rheology in paper coating compositions applied with a metering blade, rod or air knife. They provide high thickening efficiency with high pseudoplasticity in high solids content coating compositions. During blade coating a hydrophobically modified cellulosic allows lower blade pressures to be used with a resulting improvement in coating quality at high speeds. Lower blade pressure resulting from the use of associative thickeners can reduce water loss to the paper stock, web breaking and streaking, particularly at high coating speed. However, when a HMHEC is used as the sole thickener/co-binder in a clay-containing coating formulation, its highly clay adsorbing nature often results in a relatively low aqueous liquid viscosity, and hence a somewhat limited water retention capability.
The coating containing MPS 2-A has been found to give good runnability at a high coating speed of X500 feet per minute in a coater trial using a cylindrical laboratory coater (CLC). A fairly low coat weight of ca. 5.0 pounds per 3300 sq.
ft. of paper was readily attained at this high speed with a moderate blade pressure, indicating a low and manageable flow resistance of the coating. The paper sample produced with MPS
2-A was observed to have improved coated paper properties over that of the coating containing only HMHEC or CMC. As shown in Table 11, MPS 2-A gave the best combination of sheet gloss, print gloss, opacity, and ink pick strength. The Test Methods section gives a more detailed description of these measurements.
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The above data show that a MPS containing HMHEC and CMC
not only can satisfy the industry's need for a liquid product, but also can lead to improved runnabil.ity and/or coated paper quality. A MPS has additional advantages in that (1) the presence of more than one cellulosic polymer makes it possible to optimize coating properties for a large variety of paper products, and (2) the use of a relatively low level of salt in the MPS avoids excessive flocculation of pigments or the latex binder, which may occur with high salt suspensions.
HMHEC/MHEC/CMMPS
It has been found that a terpolymer MPS comprising of a HMHEC, a MC or MC derivative such as MHEC, and a low-MW CMC can also be an very effective thickener/co-binder for paper coatings. The MC derivative, which is a good binder and water retention aid, can work in combination with the HMHEC and .
CMC to provide good wet coating runnability and coated paper quality. For example, one such MPS (MPS 6-B) has been found to give a good balance of thickening efficiency, high shear viscosity and water retention in coating Formulation II (see Table 10).
The terpolymer MPS has been observed in a CLC coater trial to give good high speed runnability and coating properties. As shown in Table 11, the coated paper sample prepared with MPS 6-B showed clearly superior coated Paper properties over that of another sample produced using a commercial CMC. The use of MPS 6-B as the thickener/co-binder has caused a substantial improvement in the ink pick resistance. This improvement in coating strength is thought to arise, at least in part, from the excellent binding property of the MC derivative.
Preferred Product MPSs 2-A to 2-D and MPSs 6-A to 6-D are the preferred Products for use as paper coating thickeners/co-binders.
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Table 9 Paper Coating Formulations*
Hydrafine~ 100 -I-Iydrasperse~ - 40 Hydraprint~ - 50 Ansilex~ 93 - 5 Ti-Pure~ R-931 Dispex~ N40 - 0.15 Dow 620 13 Flowcoo 501 0.5 Hercules 831 0.2 0.2 Thickener varied varied Brookfield Vi scosity 2300 1000 *A11 ingredients in the test formulas were on a dry or 100% active basi s; The concentration of the ingredients were reported in parts per 100 parts of pigment;
pH of the coating was adjusted to 8; Z'otal solids was 60s by weight. The use level of thickener was varied to obtain the target Brook field viscosity as measured at 100 rpm.
Hydrafine: Pigment, No. 1 kaolin clay, J. M.
Huber Corp.
Hydrasperse: Pigment, No. 2 kaolin clay, J. M.
Huber Corp.
Hydraprint: Pigment, delaminated clay, J. M.
Huber Corp.
Ansilex 93: Pigment, calcined clay, Engelhard Corp.
Ti-Pure R-931: Pigment, Ti02, DuPont Dow 620: Binder, styrene-butadiene latex, Dow Chemical Co.
Flowco~ 501: Lubricant, calcium stearate dispersion, Mallinckroft Hercules 831: Defoamer, Hercules Incorporated _ 18 --n, i"' :'~ ~'~ ; , fi°
y ,,.a ~ 1 ~ ~ ~;~, t7 dJ ':g v.u Table 10 Properties of Wet Coatings Th~.~~_r D~e~ fI_~r~~ .W_~~
(Formula HMHEC 0.5 31.9 6 CMC, low MW (7LT) 2.0 65.2 14 MPS 2-A 1.0 43.7 11 (Formula II) HMHEC 0.4 38.9 5 l0 CMC, low MW 0.8 69.5 16 MPS 6-B 0.6 58.4 8 *Dose: Parts per hundred parts of pigment.
Hercules: Hercules high shear viscosity in mPa.s.
WRT: Water Retention Time in seconds.
Table 11 Coated Sheet Properties of Supercalendered Paper Samples*
Print Thickener ~ 9~acitv I T 1 ss (Formula I) CMC, low MW 65.4 83.5 77.5 83.3 HMHEC 62.6 85.3 84.0 80.3 MPS 2-A 65.4 85.3 84.0 84.6 (Formula II) CMC, Low MW 53.1 81.3 19.4 60.0 MPS 6-H 55.2 87..8 29.0 66.9 Test Methods Kaltec Scientific, Inc., 22425 Heslip Dri~re. Novi, Michigan 48050 supplies parts and rheogram paper for use with the Model ET24-6 Herculeso Hi-Shear Viscometer which is in common use by the paper industry for evaluation of coating compositions.
All paper samples were coated on one side using a cylindrical laboratory coater (manufactured by Sensor and Simulation Products, Tacoma, Washington) at a speed of from 4000 to 4500 feet per minute. The coat weight for both formulations was approximately 5.0 pounds per 3300 square _19_ ~~=:~~C.F)r.)~~~~
feet. The coated paper samples were supercalendered with four passes at 160°F and 1500 psi. Gloss of the paper samples was measured using a Gardner Glossmeter at 75° angle, and was reported as % reflectance of the incident light. The opacity was measured using a Diano Opacimeter according to TAPPI test method T--425. The IGT ink pick resistance was measured using a 32 Pa.s oil ink, and was reported as velocity-viscosity product at the onset of coating picking by the ink. A higher IGT pick resistance value indicates a higher coating strength which is desirable for high speed printing.
Water retention times of paper coatings were measured using a conductivity method which was a modification of the S.
D. Warren Water Retention Test Method, i.e., J. C. Stichfield, R. A. Clift, J. J. Thomas, TAPPI, 41 (2), 1958, p. 77.
The CMC used in this test had a nominal molecular weight of approximately 110,000 (Srookfield viscosity of 2% solution was 40 mPa.s)) this CMC product is commercially used as coating thickeners and is available from Aqualon Company.
European Patent Application EP 307-795 describes a pigment dispersion used for paper coating which can contain modified starch, galactomannan, methylcellulose (MC) or carboxymethylcellulose (CMC). A quaternary starch ether is employed in the papermaking method of U.S. Patent 4,840,705.
It is further known from Aqualon~ publication 250-11C, Natrosol~ - Hydroxyethylcellulose - A Nonionic Water-Soluble Polymer - Physical and Chemical Properties. that this cellulosic can be used in coating colors and size press solutions to control water binding, solids holdout and rheology. Hercules Incorporated product data publication 456-2, Natrosol~ in Pigmented Coatings for Paper. and Paperboard, contains viscosity data useful for selection of a grade of product fox a papermaking application.
U.S. Patents 4,228,277 and 4,243,802 describe hydrophobically modified hydroxyethylcellulose (HMHEC) fox use in latex paints and shampoos. Chain lengths from C4 to C24 can provide the hydrophobic modification.
Still it remained for the present invention to teach how two or more anionic and nonionic polysaccharides provide a fluid suspension applicable for paper manufacture.
_1_ It is an object of the invention to provide an aqueous fluidized polymer suspension comprising at least one low molecular weight polysaccharide and at least one nonionic cellulose ether polymer with a salt content below 10% by weight wherein the suspension remains fluid and pourable.
It is preferred for paper coatings that the nonionic cellulose ether polymer be a water soluble hydrophobically modified alkylcellulose, alkylhydroxyalkylcellulose or hydroxyalkylcellulose.
A process for preparing a fluidized polymer suspension involves the steps=
(1) Preparing an aqueous solution of a low molecular weight polysaccharide containing up to 10% by weight ammonium or alkali salt from the group of carbonate, sulfate, phosphate or formate~ and (2) stirring the solution while adding a nonionic cellulose ether to prepare a fluidized polymer suspension.
An anionic cellulose and hydrophobically modified cellulose ether mixture can be added as a sole thickening agent or be used in combination with other thickening agents for Paper coating compositions. Sodium carboxymethylcellulose is a preferred anionic polymer and hydrophobically modified hydroxyethylcellulose is a preferred nonionic cellulose ether polymer.
In another aspect the invention provides an aqueous paper coating composition of clay, calcium carbonate and/or gypsum, a binder selected from the group consisting of starch, protein and latex and thickener; characterized in that the thickener is a Multi-Polysaccharide Suspension (MPS) of dispersed particles of a nonionic hydrophobically modified cellulose ether selected from the group consisting of hydroxyethylcellulose, ethylhydroxyethylcellulose, methyl-cellulose, hydroxypropylcellulose, methylhydroxypropylcellulose and methyl hydroxyethylcellulose in a continuous aqueous phase of a dissolved polysaccharide selected from the group consisting of hydroxyethylcellulose, cationic starch, carboxymethylcellulose and carboxymethylguar wherein the polysaccharide is of sufficiently low molecular weight that a 15 weight percent solution will have a Hrookfield viscosity at 12 rpm at room temperature of 10,000 mPa.s or lower and the MPS
contains 10 percent by weight or less of a salt or salts from the group of sodium carbonate, potassium carbonate, sodium sulfate, diammonium phosphate and sodium formate and the MPS
contains a stabilizing amount of xanthan wherein the MPS
remains fluid and pourable.
This invention is concerned with fluid aqueous suspensions comprising at least two water-soluble polysaccharides that possess distinct properties. One of the polysaccharides in the Multi-Polysaccharide Suspension (MPS) is of a relatively low molecular weight (MW) and is dissolved in the continuous aqueous phase. One or more nonionic cellulosic polymers is present in a form of dispersed particles in the suspension. The suspension either contains no added salt or a relatively low level of inorganic salt or mixture thereof (less than 10 wt.%). The suspensions typically have a total polysaccharide concentration of 20 wt.% or higher and are -2a-Yj ':.~ i..: '':% i~' ~',.~
fluid and pourable. All of the Multi-Polysaccharide Suspensions (MPSs) described herein can be readily dispersed and dissolved in aqueous solvent.
The continuous aqueous phase of the MPS contains a dissolved low-MW polysaccharide, an inorganic salt at a concentration of 0 (salt-free) to 8 wt. % (low-salt), and rninor amounts of additives (less than 1 wt. %) which may include defoamer, dispersant, preservative, and/or suspension stabilizers such as xanthan gum. These dissolved low-MW
polysaccharide can be a CMC (anionic, e.g., Ambergum~ 1570 or Ambergum~ 3021), a hydroxyethylcellulose HEC) (nonionic, e,g., AQU-D3097), a degraded carboxymethyl guar (anionic, e.g., AQU-D3144), all of which are available from the Aqualon Company, and a starch derivative (cationic starch such as Amaizo~ 2187). These dissolved low-MW polysaccharides generally have a solution viscosity of less than 10,000 mPa.s as measured at a concentration of 15 wt. % using a Brookfield viscometer at 12 rpm. The inorganic salt (or salt mixture) for use in the preparation of the referred suspensions may be sodium formate, sodium carbonate, sodium sulfate, potassium carbonate, diammonium phosphate, or others.
The dispersed phase contains one or more Dispersed, Nonionic Cellulosic Polymer (DNCP). The DNCP can be a hydroxypropylceilulose (e.g., Klucel~ HPC), methylcellulose or methylhydroxypropylcellulose (e. g., CulminalT~ MC or Benecelr"
MHEC), hydrophobically modified hydroxyethylcellulose (e. g., Natrosol~ Plus 330 HMHEC), or hydroxyethylcellulose (e. g., Natrosol~ .HEC). Insolubilization of the DNCP, which is less hydrophilic than the dissolved polysaccharide, is primarily a result of the difference in water solubility between the dissolved polysaccharide and the DNCP. Further reduction in DNCP swelling or dissolution, where necessary, may be attained by dissolving in the aqueous phase a relatively small amount of salt, which helps reduce the amount of water accessible to the DNCP. the dissolved polysaccharide also causes an increase in the liquid phase viscosity, which reduces the rate of .. fir, ,'a ~ x.1. in 4c1 ~~i% '.:I ~, ~; n.7 i~~' ~, l settlement of the suspended polymer particles and, hence, improves suspension stability.
A MPS can be prepared by adding a DNCP to a vigorously agitated solution of the low-MW polysaccharide in which an amount of inorganic salt (or salts) at a concentration of 0 to g wt. % has been previously added. A fluid suspension is obtained after the mixture is stirred for a period of 15 to 60 minutes. A small amount of additives such as defoamer, dispersant, or suspension stabilizer may be added if necessary. Additives such as defoamer may be added before or after the DNCP has been dispersed into the aqueous solution.
The suspensions can be readily pumped and redissolved in aqueous media; the dissolution of the suspension is substantially faster than that of the nonionic cellulosic polymer. These properties can lead to a significant improvement in the efficiency of polymer solution makeup operations, and reduce or eliminate difficulties often associated with handling of dry powders of cellulosic polymers, such as powder dusting and lumping of wet particles during mixing.
This invention is intended to introduce (1) a new methodology of preparing easily processable suspensions of cellulosic polymers that contain a relatively low level of added salt, and (Z) a means to produce uniform mixtures of cellulosic polymers which can provide different functionalities in a certain application.
The MPSs are of use in various applications where one of the following conditions exist:
(a) Each of the different polysaccharides in the suspension imparts essential functionality to the end application.
(b) The DD1CP (suspended polymer) is primarily responsible for the key functionality; the dissolved polysaccharide allows (1) suspending of the functional DNCP without using a high level of salt (high salt level not tolerated in concerned 1~ ~:'~ t'?, fa ~' ',:~ ~..1 application); (2) fast and ready dissolution of the suspended polymer; and/or (3) other desirable properties that are not critical to the end application, such as added thickening/water holding or improved particle dispersion (as protective colloid in the end formulation).
2n common with other industries, the paper and paperboard manufacturers seek to improve productivity and lower mill cost. One of the problems limiting their productivity has been the necessity to employ solid thickeners in preparing suitable coating compositions.
Ideally. a paper coating thickener/co-binder should bring about desired rheological properties that allow easy mixing, pumping and recycling, and, most importantly, proper metering of the pigrnented coating. It should also lead to a coating structure which is less prone to water loss when i.n contact with paper. web during the coating operation. A
suitable combination of. coating rheology and water retention capability then leads to well--controlled coat weight and good coater runnability. An ideal thickener/co-binder should also impact the coating structure in such a way that coated paper properties such as gloss, opacity, and coating strength may be enhanced. Moreover, there is an increasing need for thickeners/co-binders in a fluid liquid form to facilitate rapid, automated coating preparation in today's high speed coating operations.
Cellulosic derivatives such as CMCs have been known for years to be effective as paper coating thickeners. As derivatives of cellulose, they have inherent affinity towards the paper substrate upon which the pigmented coating is placed. This nature, together with their water binding property and long chain structure, is largely responsible for their effectiveness as thickeners/co-binders. However, the ever increasing demands for increased coating speed and enhanced coating properties call for new products that can simultaneously provide several different but essential G1 I,"_~ C) ~'3 ~? ? ~
i. ~ ~ .; D : ~i -i ~;J ;.~ '..l functions. These demands sometimes cannot be satisfied with one single cellulosic polymer, and a product consisting of more than one cellulosic derivative, such as MPS, is needed. The following illustrates how the MPSs HMHEC/CMC and HMHEC/MC/CMC
suspensions meet the current needs f_or liquid products and various essential coating properties.
The inclusion of more than one cellulosic polymer with distinct properties in the suspension makes it possible to attain a combination of desirable coating properties that are not readily obtainable from a single polymer. For instance, a HMHEC has been shown to give a combination of strong low-shear coating structure, which helps reduce penetration of coating into the paper substrate, and low flow resistance under high shear conditions typical of blade metering at high coating speeds. It also gives generally high thickening efficiency, which means only a relatively low dosage is required to thicken the coating to a certain target viscosity, lay virtue of its self-associating nature. These properties make the HMHEC an effective light-weight coating (LWC) for papers. However, when a HMHEC is used as the sole thickener/co-binder in a clay-containing coating formulation, its highly clay adsorbing nature often results in a relatively low aqueous liquid viscosity, and hence a somewhat limited water retention capability (indicated by a relatively short water retention time for the coating). Improvement in water retention capability may be achieved by using a MPS also consisting of a CMC.
Suspensions can be readily dispersed and dissolved in a large mass of aqueous liquid. Thus, they can be added to the pigmented coating at different stages of the mixing Process, making them adaptable to various coating preparation conditions. This nature makes the MPSs suitable for highly automated coating preparation processes.
It was a surprising result to find how efficient the composition and process of the invention were in meeting the aims of the paper industry. Uniform paper surfaces can be produced using a MPS as the thickener. Higher productivity can ~l,f.c)G)r7t~
a.~ ~ c~ ..:~ ~ .;
be achieved without sacrifice. of quality or significantly increasing costs using the low salt combination of anionic and nonionic cellulosic polymer.
Cellulosic thickening agents having suitable hydrophobic modification are available from the Aqualon Company. A
preferred modified cellulosic is Natrosol~ Plus HMHEC. An Aqualon publication, Natrosolo Plus 250-18A, describes how this material functions as an associative thickener in paint, but gives no suggestion of the present invention.
A suitable low molecular weight polysaccharide is carboxymethylcellulose (CMC), available from Aqualan Company as Ambergum~ 1570 or Ambergum~ 3021. However, the suspending polymer is not limited to anionic materials since low molecular weight nonionics such as hydroxyethylcellulose (HEC) or cationics, such as AmaizoO 2187 available from American Maize, may also be used in the practice of the invention.
The suspending polymer (low molecular weight polysaccharide), whether anionic, nonionic or cationic, must be available in a state such that a 15% by weight solution gives a Brookfield viscosity at room temperature below 10,000 mPa.s.
Depending upon the needs of the paper manufacturer, it may be desirable to use one or more hydrophobically modified cellulosics in combination with one or more anionic cellulosics such as CMC. Similarly other Low molecular weight polysaccharides, such as hydroxyethylcellulose (HEC), carboxymethylguar (CM Guar) or starch derivatives, can be used as the dispersing medium for other cellulosic polyrnexs such as methylcellulose (MC), methylhydroxyethylcellulose (MHEC), methylhydroxypropylcellulose (MHPC), hydroxypropylcellulose (HPC) or hydroxyethylcellulose (HEC).
Typical ingredients fox paper coating compositions in addition to thickeners include: pigments (e. g., kaolin clay, calcium carbonate, gypsum, titanium dioxide, etc.), polymeric binder (2.g., styrene-butadiene latex, protein, starch, etc.), lubricants such as glycols and fatty acids. insolubilizers and defoamers. Once prepared as a coating composition, it is usual _7_ a..
C v,"5 !n. ~~ r1 ~ ~ 1"~
~~ ~'u ~J .: _l :~u , practice in the industry to measure viscosity and rheology properties of the composition prior to an actual test of the composition. Tn this way a body of knowledge is built up by comparison of such results with the actual quality and S reproduceability provided by any of the compositions tested.
In addition to paper coating, it is possible to find uses for MPSs in the areas of latex paints, food, pharmaceutical, personal care, and others. In these applications the polysaccharides involved in the MPS are normally employed to provide viscosity, rheology control, water.
retention, and/or formulation stability. The low salt content of the invention can be highly desirable since adverse effects of salt on the colloid chemistry of the concerned formulation may be minimized. With little or no added salt in the polysaccharide suspension, health concerns due to salt content will be minimal. Thus a salt-free or low-salt MPS of HPC, MC, or MHPC can be used in food and personal care products.
Examples 1 to 8 describe the compositions and physical properties of various types of MPSs. Total polymer concentration of these MPSs range from 20 to 30 wt. %. The weight ratio of DNCP to dissolved polysaccharide ranges from about 2.1 to 0.5. The pH values vary from 6,2 to 10.7.
Brookfield viscosities measured at 6 rpm fall between 700 and 12,000 mPa.s (cps). Example 9 illustrates the use of MPS as thickeners/co-binders in paper coating formulations, Example 1 Salt-Free Suspension Containing HPC and CMC
This example illustrates the preparation of a fluid suspension of hydroxypropylcellulose (HPC) in a solution of sodium carboxymethylcellulose (CMC). The composition of this MPS is given in Table 1. It was prepared by adding the fine HPC powders into a vigorously agitated CMC solution, followed by continued mixing for approximately 30 minutes. Minor amounts of defoamer and suspension stabilizer (xanthan gum) were predissolved in the CMC solution before the addition of HPC powders.
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The resulting MPS was found to dissolve in aqueous media significantly faster than the corresponding dry HPC product.
The time required for the suspension to attain 90% of its equilibrium solution viscosity in cold water was ca. 7.0 minutes, compared to over one hour for the dry HPC. Since this composition does not contain any added salt, it may be used as thickener, binder, or Process aid in personal care, food, pharmaceutical, and other products, where a high level of salt can cause health concerns.
The low-MW CMC used in this example was supplied as a solution product which had a solutic>n viscosity of ca. 1000 mPa.s at a concentration of 15 wt. ~>. The Klucelo hydroxypropylcellulose (HPC) and the CMC solution product, with a trade name of Ambergum~ 1570, are both available from Aqualon. The defoamer, Hercules DF 285, is available from Hercules Incorporated. The xanthan gum was obtained from Kelco. All the suspension viscosities given in this and the following examples were measured using a Brookfield LVT
viscometer at a rotating speed of 6 rpm, and are reported in mPa.s (cps).
Table 1 Composition of Salt-Free MPS Containing Hydroxypropylcellulose and CMC
HPC, Klucel~ HXF 12.0 CMC. in Ambergumm 1570 12.0 Defoamer, Hercules DF 285 0.2 Xanthan Gum, Kelzan~ S 0.4 Methyl parasept (Preservative) 0.1 Water 75.3 pH 6.2 Viscosity 6100 Wt. % polysaccharide 24.4 _g_ 6"1 ,;.,. ,.~ S.7 ~., .i,:i J' y' ' ; r_) . ,, ~~ -~.'r s.::
Example 2 Suspending a HMHEC in a CMC Solution A MPS containing a hydrophobically-modified hydroxyethylcellulose (HMHEC) and a low-MW CMC was prepared as described in Example 1. An amount of inorganic salt at a level up to 7 wt. % Haas added to the composition to supplement the low-MW CMC in insolubilizing the HMHEC. Small amounts of defoamer and preservative (methyl parasept) ~rere also added to help maintain the suspension stability. The HMHEC and CMC used in this example are available from Aqualon Company.
The MPS was made by (1) preparing an aqueous solution which captained predetermined amounts of CMC and methyl parasept, (2) dissolving the salt in the aqueous solution, which took ca. 20 to 30 minutes, (3) gradually adding the dry HMHEC solids into the aqueous solution which was under vigorous agitation, and (4) adding the defoamer. The resulting suspension was then mixed for ca. 30 minutes to ensure uniform dispersion. Typical pH and Brookfield viscosity values for the suspensions are given in Table 2.
Table 2 Compositions of MPSs Containing HMHEC and Low-MW CMC
HMHEC, Natrosol~ Plus 330 10.0 14.0 10.0 10.0 CMC, in Ambergum~ 1570 10.0 6.0 10.0 10.0 Sodium carbonate 5.0 6.2 - -Sodium sulfate - - 7.0 Diammonium phosphate - - 7.0 Defoamer 285 0.2 0.2 0.2 0.2 Methyl parasept 0.1 0.1 0.1 0.1 Water 74.7 73.5 72.7 72.7 pH 10.3 10.1 6.9 7.6 Viscosity 8400 4000 9300 5400 Wt. % Polysaccharide 20.0 20.0 20.0 20.0 MPSs of this type have been shown to be useful in paper coating applications. The use of a HMHEC/CMC MPS as a paper coating thickener/co-binder is illustrated in Example 9.
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Example 3 Suspending a MC or MC Derivati ve in a CMC Solution This example describes the preparation of MPSs containing a low-MW CMC (as described in Example 1) anti a methylcellulose or a methylcellulosederivative such as methylhydroxypropylcellulose (MHPC) or methylhydroxyethylcellulose (MHEC).
Table 3 Compositions of MPSs Containing and MC, MHPC, or MHEC
CMC
MC, Culminal~ 400 10.0 - -MHPC, Benecel0 MP943W - - 11.0 MHEC, Culminal~ C3033 - 100 CMC, in Ambergumo 1570 10.0 10.0 11.0 Sodium carbonate 2.0 2.0 Sodium sulfate 3.5 Hercules DF 285 0.2 0.2 0.2 Xanthan Gum, Kelzan~ S 0.2 0.2 0.4 Methyl parasept 0.1 0.1 0.1 Water 77.5 77.5 73.8 pH 10.3 10.3 6.7 Viscosity 4900 5500 9100 Wt. % polysaccharide 20.2 20.2 22.4 These MPSs also demonstrated faster dissolution in aqueous media than the correspondingdry MC, MHEC, or MHPC.
For instance, the time required MPS 3-C (Table 3) to attain for 90 of its equilibrium viscosity less than five minutes, in was comparison to about 40 minutes he dry Benecel~ MHEC
for t product. With the relatively low salt contents, such MPSs may find commercial use in personal and paper coating care applications.
Example 4 HEC Suspended in CMC Solutions The following MPSs demonstrate the feasibility of preparing fluid suspensions that contain a hydroxyethylcellulose (HEC) and a low--MW CMC. The procedure P
~~ ~,~ ~j ,r~ ,,~ ,r;, ~~ ~,p l~ :~~ .., y-9 for preparing the MPSs is similar to that described in Example 1. A CMC with a very low MW, which gave a solution viscosity of about 1000 cps at a concentration of 30 wt. %, was used :in this example. This low MW CMC is available as a solution product (AmbergumC~ 3021) from Aqualon Company. The I-IEC
Products are also available from Aqualon, Table 4 MPSs Containing a Suspended HEC and Dissolved CMC
HEC, Natrosol~ 250 GR 10.0 - -HEC, NatrosolC~ 250 MXR 10.0 I-IEC, Natrosolo 250 HBR - - 1U.0 CMC, in Ambergum~ 3021 10.0 10.0 10.0 Sodium carbonate 5.0 -- -Diamrnonium phosphate - 4.0 5.0 Water 75.0 76.0 75.0 pH 10.0 7.1 7.4 Viscosity 2400 2200 2000 Wt. % polysaccharide 20.0 20.0 20.0 Example 5 HPC Suspended in HEC Solution This example describes the preparation of a MPS
containing a HPC and a low-MW HEC. Success in preparing such a MPS indicates that the dissolved polymer in a MPS does not have to be ionic in nature.
The procedure of preparation was the same as that described in Example 1. The HEC used had a solution viscosity of ca. 1000 cps at a polymer concentration of 30 wt. %. Both the HEC and HPC are available from Aqualon, ~S i" !,7 ~3 ~.~.~ ~.~:~ri::.~~'~:7 Table 5 Suspension of HPC in Solution of a Low-MP1 HEC
HPC, Klucelo HX~' 10.0 HEC, in AQU-D3097 20.0 Sodium carbonate 2.0 Methyl parasept 0.1 Water 67.9 PH 8.9 Viscosity, {mPa.s) 2400 Wt. % polysaccharide 30.0 Example 6 Two Nonionic Cellulosic Polymers Suspended in CMC Solution It is possible to have two nonionic cellulosic polymers suspended in a solution of a low-MW cellulosic polymer. The compositions shown in Table 6 are examples of such terpolymer MPSs. These compositions, in general, contained a HMHEC and a MC or MC derivative in the dispersed phase and a low-MW CMC
(such as Ambergumca 1570) in the aqueous phase. The procedure for the preparation of these suspensions was similar to 'that of Example i. The DNCPs were added to the aqueous CMC solution in sequence before the addition of the defoamer.
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Table 6 MPSs Containing Two DNCPs and Dissolved One Polymer HMHEC, Natrosol~ Plus 10.0 10.0 10.0 10.0 MC, Culminal~ 400* 5.0 - - -MHEC, Culminal~ C3033~ - 8.0 - -MHPC~ Culminalo 6000 PR - - 5.0 5.0 CMC~ in Ambergum~ 1570 7.0 7.0 7.0 7.0 Sodium carbonate 6.0 6.5 6.0 -Diammonium phosphate - - - 8.0 Hercules DF 285 0.3 0.3 0.3 0.3 Methyl Parasept 0.1 0.1 0.1 0.1 Water 71.6 68.2 71.6 69.6 pH 10.1 9.8 9.9 7.6 Viscosity 5800 116005300 5700 Wt. % Polysaccharide 22.0 25.0 22.0 22.0 *The dry polymer products were ground in the laboratory to give finer particles to reduce settling of the suspended particles.
Example 7 HMHEC Suspended in Low-MW Guar Derivative A depolymerized, low-MW guar derivative. a carboxymethylated guar (CM guar) in this example, has been used to suspend a HMHEC with the aid of 6 parts of sodium carbonate. This example manifests that the dissolved polymer is not necessarily limited to cellulosic derivatives.
The low-MW CM guar is available from Aqualon as a solution product (AQL~-D3144). At a CM guar concentration of 34 wt. %, this aqueous solution had a Brookfield viscosity of 220 cps.
Table 7 MPS Containing a Low--MW CM Guar as the Dissolved Polysaccharides HMI-IEC, Natrosol~ Plus 330 10.0 CM guar, in AQIJ-D3144 10.0 Sodium carbonate 6.0 Hercules DF 285 0.2 Methyl parasept 0.1 Water 73.7 pH 9.6 Viscosity 700 Wt. % polysaccharide 20.0 Example 8 HMHEC Suspended in Starch Solution This example describes the use of another non-cellulosic polysaccharide as the dissolved polymer, a low-MW, cationic starch manufactured by American Maize (AmaizoC~ 2187). To prepare this suspension, a stock solution of the cationic starch (a dry product) was first prepared using a steam cooker. Make-up water and the salt were added to the stock solution, followed by the addition of the DNCP, a HMHEC.
Table 8 HMHEC Suspended in Starch Solution HMHEC, Natrosol~ Plus 330 10.0 Cationic starch, Amaizo~ 2187 14.3 Sodium carbonate 4.3 Methyl parasept 0.1 Water 71.3 pH 9.9 Viscosity 4200 Wt. % polysaccharide 24.3 _ 15 --Example 9 Use of MPSs as Thickener/Ca-Dinder.s for Paper Coatings This example demonstrates the use of two types of MPSs as thickeners/co-binders in paper coating formulating. One type of MPS contains HMHEC and CMC. The other contains HMHEC, CMC and MHEC.
HMHEC/CMC NIPS
Associative thickeners (i.e., hydrophobically modified cellulose ethers which associate with themselves) are useful in the practice of the present invention, providing improved rheology in paper coating compositions applied with a metering blade, rod or air knife. They provide high thickening efficiency with high pseudoplasticity in high solids content coating compositions. During blade coating a hydrophobically modified cellulosic allows lower blade pressures to be used with a resulting improvement in coating quality at high speeds. Lower blade pressure resulting from the use of associative thickeners can reduce water loss to the paper stock, web breaking and streaking, particularly at high coating speed. However, when a HMHEC is used as the sole thickener/co-binder in a clay-containing coating formulation, its highly clay adsorbing nature often results in a relatively low aqueous liquid viscosity, and hence a somewhat limited water retention capability.
The coating containing MPS 2-A has been found to give good runnability at a high coating speed of X500 feet per minute in a coater trial using a cylindrical laboratory coater (CLC). A fairly low coat weight of ca. 5.0 pounds per 3300 sq.
ft. of paper was readily attained at this high speed with a moderate blade pressure, indicating a low and manageable flow resistance of the coating. The paper sample produced with MPS
2-A was observed to have improved coated paper properties over that of the coating containing only HMHEC or CMC. As shown in Table 11, MPS 2-A gave the best combination of sheet gloss, print gloss, opacity, and ink pick strength. The Test Methods section gives a more detailed description of these measurements.
_16-u,°~ ~'~ ~ so ,y~ ,n ~~~U>>l.J~~
The above data show that a MPS containing HMHEC and CMC
not only can satisfy the industry's need for a liquid product, but also can lead to improved runnabil.ity and/or coated paper quality. A MPS has additional advantages in that (1) the presence of more than one cellulosic polymer makes it possible to optimize coating properties for a large variety of paper products, and (2) the use of a relatively low level of salt in the MPS avoids excessive flocculation of pigments or the latex binder, which may occur with high salt suspensions.
HMHEC/MHEC/CMMPS
It has been found that a terpolymer MPS comprising of a HMHEC, a MC or MC derivative such as MHEC, and a low-MW CMC can also be an very effective thickener/co-binder for paper coatings. The MC derivative, which is a good binder and water retention aid, can work in combination with the HMHEC and .
CMC to provide good wet coating runnability and coated paper quality. For example, one such MPS (MPS 6-B) has been found to give a good balance of thickening efficiency, high shear viscosity and water retention in coating Formulation II (see Table 10).
The terpolymer MPS has been observed in a CLC coater trial to give good high speed runnability and coating properties. As shown in Table 11, the coated paper sample prepared with MPS 6-B showed clearly superior coated Paper properties over that of another sample produced using a commercial CMC. The use of MPS 6-B as the thickener/co-binder has caused a substantial improvement in the ink pick resistance. This improvement in coating strength is thought to arise, at least in part, from the excellent binding property of the MC derivative.
Preferred Product MPSs 2-A to 2-D and MPSs 6-A to 6-D are the preferred Products for use as paper coating thickeners/co-binders.
~", j" ~;? "~ ,~i ('A
~ ;r ~J ~:.i :.t~ 1..: ',~ ;..,. '~,~
Table 9 Paper Coating Formulations*
Hydrafine~ 100 -I-Iydrasperse~ - 40 Hydraprint~ - 50 Ansilex~ 93 - 5 Ti-Pure~ R-931 Dispex~ N40 - 0.15 Dow 620 13 Flowcoo 501 0.5 Hercules 831 0.2 0.2 Thickener varied varied Brookfield Vi scosity 2300 1000 *A11 ingredients in the test formulas were on a dry or 100% active basi s; The concentration of the ingredients were reported in parts per 100 parts of pigment;
pH of the coating was adjusted to 8; Z'otal solids was 60s by weight. The use level of thickener was varied to obtain the target Brook field viscosity as measured at 100 rpm.
Hydrafine: Pigment, No. 1 kaolin clay, J. M.
Huber Corp.
Hydrasperse: Pigment, No. 2 kaolin clay, J. M.
Huber Corp.
Hydraprint: Pigment, delaminated clay, J. M.
Huber Corp.
Ansilex 93: Pigment, calcined clay, Engelhard Corp.
Ti-Pure R-931: Pigment, Ti02, DuPont Dow 620: Binder, styrene-butadiene latex, Dow Chemical Co.
Flowco~ 501: Lubricant, calcium stearate dispersion, Mallinckroft Hercules 831: Defoamer, Hercules Incorporated _ 18 --n, i"' :'~ ~'~ ; , fi°
y ,,.a ~ 1 ~ ~ ~;~, t7 dJ ':g v.u Table 10 Properties of Wet Coatings Th~.~~_r D~e~ fI_~r~~ .W_~~
(Formula HMHEC 0.5 31.9 6 CMC, low MW (7LT) 2.0 65.2 14 MPS 2-A 1.0 43.7 11 (Formula II) HMHEC 0.4 38.9 5 l0 CMC, low MW 0.8 69.5 16 MPS 6-B 0.6 58.4 8 *Dose: Parts per hundred parts of pigment.
Hercules: Hercules high shear viscosity in mPa.s.
WRT: Water Retention Time in seconds.
Table 11 Coated Sheet Properties of Supercalendered Paper Samples*
Print Thickener ~ 9~acitv I T 1 ss (Formula I) CMC, low MW 65.4 83.5 77.5 83.3 HMHEC 62.6 85.3 84.0 80.3 MPS 2-A 65.4 85.3 84.0 84.6 (Formula II) CMC, Low MW 53.1 81.3 19.4 60.0 MPS 6-H 55.2 87..8 29.0 66.9 Test Methods Kaltec Scientific, Inc., 22425 Heslip Dri~re. Novi, Michigan 48050 supplies parts and rheogram paper for use with the Model ET24-6 Herculeso Hi-Shear Viscometer which is in common use by the paper industry for evaluation of coating compositions.
All paper samples were coated on one side using a cylindrical laboratory coater (manufactured by Sensor and Simulation Products, Tacoma, Washington) at a speed of from 4000 to 4500 feet per minute. The coat weight for both formulations was approximately 5.0 pounds per 3300 square _19_ ~~=:~~C.F)r.)~~~~
feet. The coated paper samples were supercalendered with four passes at 160°F and 1500 psi. Gloss of the paper samples was measured using a Gardner Glossmeter at 75° angle, and was reported as % reflectance of the incident light. The opacity was measured using a Diano Opacimeter according to TAPPI test method T--425. The IGT ink pick resistance was measured using a 32 Pa.s oil ink, and was reported as velocity-viscosity product at the onset of coating picking by the ink. A higher IGT pick resistance value indicates a higher coating strength which is desirable for high speed printing.
Water retention times of paper coatings were measured using a conductivity method which was a modification of the S.
D. Warren Water Retention Test Method, i.e., J. C. Stichfield, R. A. Clift, J. J. Thomas, TAPPI, 41 (2), 1958, p. 77.
The CMC used in this test had a nominal molecular weight of approximately 110,000 (Srookfield viscosity of 2% solution was 40 mPa.s)) this CMC product is commercially used as coating thickeners and is available from Aqualon Company.
Claims (15)
1. A process for preparing a fluidized polymer suspension comprising the steps of:
(1) preparing an aqueous solution of a low molecular weight polysaccharide containing up to loo by weight of an ammonium or alkali salt selected from the group consisting of carbonate, sulfate, phosphate and formate; and (2) stirring the solution while adding one or more nonionic cellulose ethers to prepare a fluidized polymer suspension.
(1) preparing an aqueous solution of a low molecular weight polysaccharide containing up to loo by weight of an ammonium or alkali salt selected from the group consisting of carbonate, sulfate, phosphate and formate; and (2) stirring the solution while adding one or more nonionic cellulose ethers to prepare a fluidized polymer suspension.
2. The process of claim 1, further characterized in that a preservative is added.
3. The process of claim 1 or 2, further characterized in that a defoamer and stabilizer are added to produce a storage stable suspension.
4. The process of claim 1, 2 or 3 where the cellulose ether is hydroxyethylcellulose or hydrophobically modified hydroxyethylcellulose and the low molecular weight poly-saccharide is CMC or CM Guar.
5. The process of claim 4, further characterized in that the suspension has a weight percent solids above 20%
and a Brookfield viscosity at 6 rpm below 10,000 mPa.s.
and a Brookfield viscosity at 6 rpm below 10,000 mPa.s.
6. The process of claim 5, further characterized in that the hydroxyethylcellulose is hydrophobically modified with a nonylphenyl, alkenyl, succinic or cetyl group.
7. A process for preparing a fluidized polymer suspension comprising the steps of:
(1) preparing an aqueous solution of a low molecular weight polysaccharide selected from the group of HEC, CMC, CM Guar and cationic starch by stirring for a time sufficient to dissolve the solids;
(2) adding a nonionic cellulose ether to the stirred solution; and (3) adding a defoamer and/or a stabilizer to prepare a fluidized polymer suspension has a Brookfield viscosity of at least 4000 mPa.s at 25°C.
(1) preparing an aqueous solution of a low molecular weight polysaccharide selected from the group of HEC, CMC, CM Guar and cationic starch by stirring for a time sufficient to dissolve the solids;
(2) adding a nonionic cellulose ether to the stirred solution; and (3) adding a defoamer and/or a stabilizer to prepare a fluidized polymer suspension has a Brookfield viscosity of at least 4000 mPa.s at 25°C.
8. The process of claim 7 where methyl parasept preservative is added in step (1).
9. The process of claim 7 or 8 where the cellulose ether is hydrophobically modified hydroxyethylcellulose.
10. The process of claim 7, 8 or 9 where the low molecular weight polysaccharide is CMC.
11. The process of claim 7, 8, 9, or 10 where the stabilizer is xanthan gum.
12. An aqueous paper coating composition of clay, calcium carbonate and/or gypsum, a binder selected from the group consisting of starch, protein and latex and thickener;
characterized in that the thickener is a Multi-Polysaccharide Suspension (MPS) of dispersed particles of a nonionic hydrophobically modified cellulose ether selected from the group consisting of hydroxyethylcellulose, ethylhydroxyethylcellulose, methylcellulose, hydroxypropylcellulose, methylhydroxypropylcellulose and methyl hydroxyethylcellulose in a continuous aqueous phase of a dissolved polysaccharide selected from the group consisting of hydroxyethylcellulose, cationic starch, carboxymethylcellulose and carboxymethylguar wherein the polysaccharide is of sufficiently low molecular weight that a 15 weight percent solution will have a Brookfield viscosity at 12 rpm at room temperature of 10,000 mPa.s or lower and the MPS contains 10 percent by weight or less of a salt or salts from the group of sodium carbonate, potassium carbonate, sodium sulfate, diammonium phosphate a.nd sodium formate and the MPS contains a stabilizing amount of xanthan wherein the MPS remains fluid and pourable.
characterized in that the thickener is a Multi-Polysaccharide Suspension (MPS) of dispersed particles of a nonionic hydrophobically modified cellulose ether selected from the group consisting of hydroxyethylcellulose, ethylhydroxyethylcellulose, methylcellulose, hydroxypropylcellulose, methylhydroxypropylcellulose and methyl hydroxyethylcellulose in a continuous aqueous phase of a dissolved polysaccharide selected from the group consisting of hydroxyethylcellulose, cationic starch, carboxymethylcellulose and carboxymethylguar wherein the polysaccharide is of sufficiently low molecular weight that a 15 weight percent solution will have a Brookfield viscosity at 12 rpm at room temperature of 10,000 mPa.s or lower and the MPS contains 10 percent by weight or less of a salt or salts from the group of sodium carbonate, potassium carbonate, sodium sulfate, diammonium phosphate a.nd sodium formate and the MPS contains a stabilizing amount of xanthan wherein the MPS remains fluid and pourable.
13. The coating composition of claim 12 wherein the dispersed particles comprise hydrophobically modified hydroxyethylcellulose.
14. The coating composition of claim 12 or 13 wherein the low molecular weight polysaccharide is carboxymethylcellulose.
15. The coating composition of claim 14 further comprising one or more of methylcellulose, methylhydroxypropylcellulose or methylhydroxyethylcellulose.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US645,549 | 1991-01-24 | ||
| US07/645,549 US5080717A (en) | 1991-01-24 | 1991-01-24 | Fluid suspensions of polysaccharide mixtures |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2058326A1 CA2058326A1 (en) | 1992-07-25 |
| CA2058326C true CA2058326C (en) | 2003-12-16 |
Family
ID=24589452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002058326A Expired - Fee Related CA2058326C (en) | 1991-01-24 | 1991-12-31 | Process for preparing fluid suspensions of polysaccharide mixtures |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5080717A (en) |
| EP (1) | EP0496269B1 (en) |
| JP (1) | JP2620832B2 (en) |
| AU (1) | AU652020B2 (en) |
| CA (1) | CA2058326C (en) |
| DE (1) | DE69218269T2 (en) |
| FI (1) | FI104256B1 (en) |
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| DK0562341T3 (en) * | 1992-03-26 | 1999-11-08 | Aqualon Co | Fluidized polymer suspension (FPS) for continuous preparation of coating composition |
| ATE170207T1 (en) * | 1992-04-20 | 1998-09-15 | Aqualon Co | AQUEOUS COATING COMPOSITIONS WITH IMPROVED LEVELING |
| US6576048B1 (en) * | 1993-09-14 | 2003-06-10 | Charles Lee Burdick | Use of high bulk density methylcelluloses in aqueous fluid polymer suspensions |
| US5494509A (en) * | 1993-10-29 | 1996-02-27 | Aqualon Company | Paper coating composition with increased thickener efficiency |
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| SE506674C2 (en) * | 1996-06-05 | 1998-01-26 | Akzo Nobel Surface Chem | Composition, use of a cellulose ether as a thickener and preparation of a coated cellulose-based surface product |
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| FI108283B (en) * | 1997-01-13 | 2001-12-31 | M Real Oyj | Procedure for coating paper and cardboard |
| US6905694B1 (en) | 1997-05-12 | 2005-06-14 | Hercules Incorporated | Hydrophobically modified polysaccharide in personal care products |
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| SE518782C2 (en) | 2000-07-19 | 2002-11-19 | Akzo Nobel Nv | Use of an alkyl hydroxyalkyl cellulose to improve gloss and printability as well as an aqueous coating composition |
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| EP1417240A1 (en) | 2001-06-11 | 2004-05-12 | Rhodia, Inc. | Galactomannan compositions and methods for making and using same |
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| US20030173045A1 (en) * | 2002-03-18 | 2003-09-18 | Philip Confalone | Liquid starch dispersions for coated paper and paperboard |
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| GB0304354D0 (en) * | 2003-02-26 | 2003-04-02 | Ciba Spec Chem Water Treat Ltd | Modification of paper coating rheology |
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| US20050101490A1 (en) * | 2003-11-11 | 2005-05-12 | Vollmer Daniel P. | Cellulosic suspensions of alkali formate and method of using the same |
| US20050101491A1 (en) * | 2003-11-11 | 2005-05-12 | Vollmer Daniel P. | Cellulosic suspensions employing alkali formate brines as carrier liquid |
| US7731794B2 (en) | 2005-06-09 | 2010-06-08 | United States Gypsum Company | High starch light weight gypsum wallboard |
| US9840066B2 (en) * | 2005-06-09 | 2017-12-12 | United States Gypsum Company | Light weight gypsum board |
| US20110195241A1 (en) * | 2005-06-09 | 2011-08-11 | United States Gypsum Company | Low Weight and Density Fire-Resistant Gypsum Panel |
| US11338548B2 (en) | 2005-06-09 | 2022-05-24 | United States Gypsum Company | Light weight gypsum board |
| US9802866B2 (en) | 2005-06-09 | 2017-10-31 | United States Gypsum Company | Light weight gypsum board |
| US11306028B2 (en) | 2005-06-09 | 2022-04-19 | United States Gypsum Company | Light weight gypsum board |
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| US20080075964A1 (en) * | 2006-03-07 | 2008-03-27 | Burdick Charles L | Paper coatings containing hydroxyethylcellulose rheology modifier and high levels of calcium carbonate pigment |
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| BRPI1011056A2 (en) * | 2009-05-19 | 2019-09-24 | Cargill Inc | polysaccharide compositions. |
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| BR112012004679A2 (en) * | 2009-09-01 | 2020-08-11 | Rhodia Operations | polymeric compositions |
| US9181659B2 (en) * | 2011-10-17 | 2015-11-10 | Cp Kelco Oy | Compositions having increased concentrations of carboxymethylcellulose |
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| CN106028809A (en) * | 2014-02-21 | 2016-10-12 | 巴斯夫欧洲公司 | Aqueous agroformulation comprising suspended pesticide, cellulose ether and thickener |
| CN106893115B (en) * | 2017-03-01 | 2018-04-17 | 广东浪淘砂新型材料有限公司 | A kind of high concentration non-ionic celluloses ether suspended dispersed liquid and preparation method thereof |
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| EP4296310A1 (en) * | 2022-06-24 | 2023-12-27 | Nouryon Chemicals International B.V. | High solids content cellulose ether solution |
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| US2377834A (en) * | 1942-07-04 | 1945-06-05 | Dow Chemical Co | Reducing syneresis of methyl cellulose |
| DE2805907B2 (en) * | 1978-02-13 | 1980-12-18 | Hoechst Ag, 6000 Frankfurt | Process for the production of a stable cellulose ether suspension and its use |
| US4313765A (en) * | 1980-09-24 | 1982-02-02 | Merck & Co., Inc. | Synergistic blends of cellulase-free xanthan gum and cellulosics |
| US4558079A (en) * | 1984-01-24 | 1985-12-10 | Hercules Incorporated | Tape joint cement composition |
| JPS6185482A (en) * | 1984-10-02 | 1986-05-01 | Daicel Chem Ind Ltd | Binder for carving material |
| JPH0643577B2 (en) * | 1986-06-27 | 1994-06-08 | ダイセル化学工業株式会社 | Wall paste |
| US4883536A (en) * | 1988-08-05 | 1989-11-28 | Aqualon Company | Suspension of water-soluble polymers in aqueous media containing dissolved salts |
| US5080717A (en) * | 1991-01-24 | 1992-01-14 | Aqualon Company | Fluid suspensions of polysaccharide mixtures |
-
1991
- 1991-01-24 US US07/645,549 patent/US5080717A/en not_active Expired - Lifetime
- 1991-12-31 CA CA002058326A patent/CA2058326C/en not_active Expired - Fee Related
-
1992
- 1992-01-15 DE DE69218269T patent/DE69218269T2/en not_active Expired - Fee Related
- 1992-01-15 EP EP92100597A patent/EP0496269B1/en not_active Expired - Lifetime
- 1992-01-16 FI FI920200A patent/FI104256B1/en active
- 1992-01-22 JP JP4009412A patent/JP2620832B2/en not_active Expired - Lifetime
- 1992-01-23 AU AU10433/92A patent/AU652020B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| EP0496269A3 (en) | 1993-06-09 |
| US5080717A (en) | 1992-01-14 |
| EP0496269B1 (en) | 1997-03-19 |
| FI104256B (en) | 1999-12-15 |
| JPH04333696A (en) | 1992-11-20 |
| DE69218269T2 (en) | 1997-06-26 |
| JP2620832B2 (en) | 1997-06-18 |
| DE69218269D1 (en) | 1997-04-24 |
| AU1043392A (en) | 1992-07-30 |
| FI920200A0 (en) | 1992-01-16 |
| CA2058326A1 (en) | 1992-07-25 |
| FI920200A (en) | 1992-07-25 |
| AU652020B2 (en) | 1994-08-11 |
| EP0496269A2 (en) | 1992-07-29 |
| FI104256B1 (en) | 1999-12-15 |
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