CA1096524A

CA1096524A - Size for glass fiber which provides improved forming and bonding properties

Info

Publication number: CA1096524A
Application number: CA232,435A
Authority: CA
Inventors: Fred G. Krautz
Original assignee: Owens Corning Fiberglas Corp
Current assignee: Owens Corning
Priority date: 1974-10-03
Filing date: 1975-07-29
Publication date: 1981-02-24
Also published as: FR2286800A1; SE7510989L; SE410444B; DE2538059A1; FI752765A; NO753348L; FI58905B; FR2286800B1; AU8416975A; BR7505726A; JPS5938173B2; GB1522148A; IT1043063B; JPS5164092A; NL7511691A; DK448275A; NO148716B; NO148716C; BE833355A; FI58905C

Abstract

ABSTRACT OF THE DISCLOSURE

A water size containing an emulsion of a film forming polymer, and the reaction product of a secondary amine and a fatty acid as a combination wet lubricant, innocuous dry lubri-cant, and bonding agent. The secondary amine has two side chains each of which contain an OH group. These side chains may have appreciable lengths provided there is one oxygen atom for every 4 carbon atoms.

Description

~L096524 Glass fibers which are to be used as a reinforcement for thermoplastic and/or thermosetting resins are made by pulling molten streams of glass until they solidify into filaments, grouping the filaments together into a strand, and coiling the strand into a package on a revolving mandrel. Glass fibers scratch easily and thereafter break when they are pulled and bent over guide surfaces. To avoid ~reaking, the prior art has always coated ~he filaments immediately after solidification and before the fibers are drawn together into a strand with a water solution of a film former and a lubricant. The lubricant provides lubricity in the wet condition between the filaments, and between the strand and guide surfaces over which the strand is drawn. Heretofore, a combination of a cationic lubricant and a nonionic lubricant has usually been used because the cationic would not provide proper lubrication after the strand was dried, and the nonionic lubricant would not provide lubrica-tion when the strand was wet. In addition, heretofore, the lubricants which have been used have interfered with the bonding between the film forming polymers and the glass fibers.
Additionally, the lubricants have also interfared with the bonding of the strand to the matrix resin which the strand was used to reinforce. Heretofore, therefore, the lubricants which have been used have been a necessary evii, and in all instances with which I am familiar, they have decreased the strength of the reinforced polymers which have been made. This has been determined by producing the strands with various amounts of the lubricants, and plotting the strength of the resulting laminates.
The decrease in the strength of the resulting lamina~e has usually been more than could be accounted for by reason of the broken filaments alone.

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According to one aspect of the invention an aqueous size composition for coating glass fibers for reinforcing a nylon polymer comprises the following solids in parts by weight:

Emulsified particles of 5.0 - 12.0 an epoxy film former Polyurethane : 0,5 - 7.0 Silane glass coupling agent Q.l - 5.0 Cationic lubricant 0.1 - S.0 wherein said cationic lubricant is the reaction product of a fatty acid and a secondary amine having two organo side chains each of which have a carbon to oxygen ratio of no more than 4 to 1 and each of which includes at least one OH group.

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According to a further aspect of the lnvention there is provided a glass fiber reinforced plastic article wherein the glass fibers have a coatiny of the following solids in ~he following parts by weight:

Emulsified particles of an epoxy film former 5.0 to 12 Polyurethane 0.5 to 7 Silane glass coupling agent 0.1 to 5 Cationic lubrican 0.1 to 5 wherein said cationic lubricant is the reaction product of a fatty acid and a secondary amine having two organo side chains each of which have a carbon to oxygen ratio of no more than 4 to 1 and each of which includes at least one OH group.
:~ A principal object of the present invention, therefore, is the provision of a new and improved size containing a material which will not only protect and lubricate the glass fibers during the wet condition, but will also protect the fibers in the dried condition without decreasing the strength of the resulting re-inforced polymers produced therewith; and which hopefully in-creases the strength of the resulting reinforced polymeric materials.

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Thermoplastic polymers are the most difficult to rein-force because of their lack of chemical functionality. The pre-ferred size for glass fibers comprises a thermoplastic polymer and a lubricant which adequately lubricates glass fibers during their wet and dried conditions, and which also aids in the bond-ing of the thermoplastic polymer to the glass fibers.
Further features and advantages will become apparent to those skille~l in lhe art from khe following description of the preferred e~odiments.
DESCRIPTION OF T~E PREFERRED EMBODIMENTS

A size was made from -the following materials in the parts by weight given below:
Materials Parts by Weight -FSE-l epoxy emulsion (55% solids) 12.7 Wyandotte X1042* polyurethane 1.0 latex (50% solids) Gamma-aminopropyltri.methoxysilane 1.4 Glass lubricant - reaction product 1.0 of diethanolamine and stearic acid Deionized water 83.9 The si~e was prepared by adding the gamma-aminopropyltrimethoxy-silane to half of the water under agitation until hydrolyzed, and the urethane latex was then added with agitation until thoroughly mixed. Thereafter the epoxy emulsion is added and thoroughly mixed for 5 minutes. In another mixing tank the glass l~bricant is adde~d to 30 parts by weight of water a~ 120F.

* A regi~ter~d Trade Mark ~1 ~19~5Z~

and is mixed until dissolved. This glass lubricant solution is then added to the main mix and agitated until a homogeneous dispersion is achieved, and the balance of the water is then added.
The above size was applied to 816 E-ylass fibers having a diameter of between .00035 and .00060 inch at forming using a belt type applicator and the wetted strand is coiled into a package at 3800 FPM and dried for 24 hours in a heated oven at 265F. The fibers so produced have a coating thereon which comprises approximately 0.5% by weight of the coated strand~
The coated strands are chopped into approximately ~ inch lengths.
Thirty parts of these coated short fibers-are then placed in a drum tumbler with 70 parts of Nylon 66 having a melting index of 2.0 and a molecular weight of approximately lO0,000. This mixture is then placed in a l-inch National Rubber machine screw extruder which is electrically heated to 540F. and the mixture is extruded into 1/8 inch diameter cylindrical rods which are then fed into a Cumberland pelletizer to form ~ inch long pellets. The pellets are in turn fed to an injection molding machine heated to 550F. and the material is injected into a standard ASTM D-633 dogbone test specimen, which when cooled at room temperature and tested in a standard tensile testing machine broke when a force equal to 25,000 psi was applied to the specimen. The material also has a modulus of elasticity of 1.2 x loS.
- By way of comparison, and not according to the invention, glass fibers were coated with a prior art size of the following composition:
Materials Parts by Weight PV Acetate (55% solids) 13.0 Gamma-aminopropyltrimethoxysilane 1.4 ~9~5~4 Polyoxyethylene-monooleate 1.0 Fibers coated with this material, using the same procedure of Example 1, give tensile strengths of only 20,000 psi at the same fiber loading given above. This polyvinyl acetate size is selected for comparison because polyvinyl acetate is known to have good wetting and coupling properties to the surface of glass fibers and has long been an accepted standard.

The process of Example 1 was repeated using the size formulation of Example 1 excepting that no glass lubricant was used, and the fibers were formed at a reduced speed of 2,000 FPM
and with great care. The resulting test specimen had a strength of only 22,000 psi, and the strand did not have sufficient lubricating properties that it could be made on a commercial basis.

The process of Example 1 was xepeated excepting that the amount of the glass lubricant was decreased to 0.5 parts by weight~ mhe resulting test specimen had a strength of 24,500 psi.

The process of Example 1 was repeated excepting that the polyurethane emulsion was deleted. The test specimen so produced had substantially the same strength as did the test specimen of Example 1.

The process of Example 1 was repeated excepting that the amount of the glass lubricant was increased to 2%. The test specimen so produced had a strength of 24,500 psi.

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` The process of Example 1 was repeated excepting that n-beta-(aminoethyl)gamma-aminopropyltrimethoxysilane was substituted for the gamma-aminopropyltrimethoxysilane coupling agent. The test specimen so produced had a strength of approximately 25,000 psi.

The process of Example 1 was repeated excepting that a forming size of the following composi~ion was used:
Materials Parts by Weight Water soluble epoxy of the 2.0 formula given-below FSE-l epoxy emulsion (55% solids) 13.0 Gamma-aminopropyltrimethoxysilane 1.0 glass coupling agent Deionized water 90.0 The water soluble epoxy had the following formula: ' -H-CH2-CH2~ ~ ~3 OH
N-CH2-CH-CH2-----~-CH2-CH-CH2 _ ; -O ~ -O-~H2-CH-C I2 ~ CH2-CH2 ~ O-C-(CH2) -CH=C~-20 ~CH2)7 CH3 The size was produced by adding the soluble epoxy to ~ of the water with sufficient acetic acid to solubilize the material.
The glass coupling agent was added thereto and thoroughly mixed.
; Thereafter the epoxy emulsion was added and thoroughly mixed for 5 minutes. In another mixing tank, the glass lubricant was added to 30 parts by weight of water at 126F. and mixed until dissolvea. The glass lubricant solution was then added to the main mix and agitated until a homogeneous dispersion was achieved, .

following which the balance o~ the water was added.
The above size was applied to the glass fibers using the procedure of Example 1 excepting that the fibers were formed at 2,200 feet per minute and were dried for 24 hours in a heated oven at 265F. The fibers so produced have a coating thereon which comprises approximately 1.0% by weight of the coated strand. The coated strand was chopped into approximately 1/8th inch lengths. These fibers when tested in the manner described in Example 1 above provided a test specimen having a strength of 25,000 psi in the Nylon 66 matrix.
By way of comparison, and not according to the invention, the above procedure was repeated excepting that the glass lubricant was deleted, and the test specimen so prepared had a strength of approximately 21,000 psi~
S ExAMæLE 8 The process of Example 7 was repeated excepting that the glass coupling ag~nt was deleted, and the test specimen so prepared had a strengkh of approximately 20,000 psi.

The process of Example 7 was repeated excepting that the matrix resin used in the production of the dogbone samples was a Nylon 612 having a M.W. of 150,000 instead of Nylon 66.
These test specimens have a strength of 27,000 psi.

The process of Example 1 is repeated excepting that a polycarbonate having a molecular weight of 150,000 and a melting index of 2 is used in place of the Nylon 66 matrix polymer. In addition, the extruder was operated at a temperature of 570F.
and the molding machine was operated at a temperature of 580F.
The amount of chopped glass fibers used-was only 20% of the ~''~' ''~i'; ' /,' ~ ' 6 , .

polycarbonate glass fiber mixture, and the tensile strength of the test specimen was d~termined to be 17,000 psi. By way of comparison, and not according to the present invention, test specimens similarly produced excepting that the glass fibers contained a prior art polyvinyl acetate size have a s-trength of only 14,000 psi.

The process of Example 1 is repeated excepting that polybutyleneglycol-terephthalate polyester having a molecular weight of 180,000 and a melting index of 3, made by reacting 1 mole of polybutyleneglycol with one mole of terephthalic acid was substituted for the Nylon 66, and an extrusion temperature of 480F. and a molding temperature of 490F. was used. The test specimen so produced had a tensile strength of 19,000 psi whereas the same material reinforced by glass fibers using a prior art polyvinyl acetate size only has a tensile strength of 13,000 psi.
EXAMP~E 12 Ninety-nine and one half parts of the Nylon 66 used in Example 1 is mixed with 0.5 parts of the reaction product of diethanolamine and stearic acid, as a mold release agent. Dogbone samples are made using the same procedure given in Example 1 and these samples are easily removed from the mold and have a strength as good as or slightly better than do samples of - specimens made from the Nylon 66 by itself. It is clear that any reaction product of a fatty acid and a secondary amine having two organo side chains each of ~7hich have a carbon to oxygen ratio of no more than 4:1, and each~of which includes at least one OH
group, operate as mold release agents for thermoplastic polymers, and ~7hen so used will be effective in amounts of from 0.1% to 2% of the molding compound.

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The process of Example 7 was repeated excepting that an emulsion of a polyester was used in place of the epoxy film formers of Example 7. The polyester was made by reacting 1 mole of ortho-phthalic acid and 1 mole of succinic acid, and 2.4 moles of propylene glycol to an acid number of 30 to 35. An emulsion was made of the following materials in percent by weight:
Materials Percent by ~eight 10 Polyester described above 47,5 Xylene 5.3 Diacetone alcohol 10.6 Wyandotte Chem. Co. Pluronic L101 * 2.
Wyandotte Chem. Co. Pluronic P105 7.8 Water 26.2 An emulsion was prepared by diluting the polyester with the xyleneO The Pluronics were dissolved in the diacetone alcohol and the solution was added to the polyester solution. Water was then added slowly with agitation until the inversion point was reached~ following which the balance of the water was added and thoroughly mixed. The polyester emulsion so produced when substituted for the epoxy materials yave substantially the same results as did the materials of Example 7.

The process of Example 1 is repeated excepting that 1.25% of the reaction product of butyl ethyl, 2,2'dihydroxy-amine and oleic acid is substituted for the lubricant of Example 1 and the test specimen has substantially the same properties.
*A Registered Trade Mark "~3 , s~ ~

The process of Example 14 is repeated excepting that the lubricant is the reaction product of butyl ethyl, 3,2' ~
dihydroxy-amine and pelargonic acid, and the test specimen has substantially the same strength as that of ~xample 1.

The process of Example 1 is repeated excepting that the lubricant is the reaction product of di-2-hydrindyl, 1,1' -dihydroxy-amine and stearic acid, and the test specimen has substantially the same properties as does the specimen of Example 1.

The process of Example 1 is repeated excepting that the lubricant is the reaction product of dipropyl 3, 3' diallyloxy-2,2'-dihydroxy-amine and stearic acid, and the test specimen has substantially the same properties as does the specimen of Example 1.

The process of Example 1 is repeated excepting that : the lubricant is the reaction product o~ diisopropanolamine and stearlc acid, and the test specimen has substantially the same properties as does the specimen of Example 1.
E~MæLE 19 The process of Example 1 is repeated excepting that the lubricant is the ethylene oxide adduct of the lubricant used ~9~SZ4 in Example 1. This adduct has an average o~ 4 ethylene oxide groups per molecule in the hydroxy-containing side chains of the amine that is reacted with the stearic acid. The test specimens produced have substantially the same properties as do those of Example 1.
From the above data it will be seen that there is a cooperation between the lubricants used in the present invention and the film formers which provides improved lubricity and protection during the wet and dry stages of strand formation and processing, while at the same time providing an increased bonding action between the coated glass fibers and the matrix polymer which the fibers reinforce. It will be seen that the lubricant is a reaction product of a fatty acid and a secondary amine, which secondary amine has two side-chains each of which has at least one OH group therein~ The amine nitrogen plus the OH groups provide a strong hydrophilic radical which is capable of carrying the fatty acid into solution therewith. These solubilizing side chains may include hydrocarbon fractions pxovided that they also include oxygen atoms in a ratio of at least one oxygen atom for every 4 carbon atoms~
The improved lubricant portion of the inventive size formulations, therefore, comprises a molecule having a single fatty acid tail that forms an ester with amine hydrogen. The other side of the amine nitrogen are two side chains, each of which has OH functionality. It is known that glass fibers when wetted with water hold a layer of water on the surface of the glass which-tends to be-high in OH groups. The lubricant of the present invention differs from most prior art lubricants in that the lubricant is linear in nature with the OH groups on one side o~ the amine nitrogen and the fatty acid radical portion on the .

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~9~Z4 opposite side of the amine nitrogen. The nitrogen becomes cationic in the size formulation and so is attracted to the surface of the glass, with the OH containing chains projecting into the water layer on the surface of the glass fibers, and with the fatty acid radicals extending generally perpendicular thereto in close pack formation. In most prior art size formulations, the cationic lubricants, particularly where they are not linear, may lay flatwise on the glass to provide hinderance to the attachment of other molecules to the glass surface. In the size formulation of the present invention, the lubricants are believed to form a coating wherein the fatty acid portions of the molecules extend parallel to each other away from the surface of the glass to provide a substantial coating thickness on the glass surface in which the lubricant portion of the molecules are oriented outwardly in close pack formation.
The fibers, therefore, are completely separated by coatings of a substantial nature having a lubricous surface. Even after the fibers are dried, it appears that at least some of the cationic lubricant remains to lubricate the surface of the glass.
When the coated fibers are embedded in a matrix resin, including a thermoplastic matriY. resin, however, the lubricant molecules leave th~ glass and diffuse between the polymer chains.
Because the lubricant used in the present invention has two -^
side chains, each of which has at least one OH group thereon, these side chains are capable of hydrogen bonding to polar elements of the matrix polymer. Since there are two OH groups, one on each side chain, one side chain is capable of bonding to one polymer molecule while th~ other side chain is capable of hydrogen bonding to the adjacent polymer molecule. This functionality lS believed to account for the increase in strength ~6~iZ~

that it provides to the matrix polymer. Because the lubricant molecules are essentially linear, the fatty acid radical portion or lubricating portion is capable of laying down between the polymer chains to act as an innocuous plasticizer, which in some instances may decrease the brittleness of the matrix polymer. As pointed out previously, the side chains containing the OH groups may have appreciable length provided that they contain at least one oxygen for every 4 carbon atoms. Since this oxygen is also capable of hydrogen bonding, and is also capable of contributing to water solubility, the additional oxygen atoms offset the hydrophobic nature of the carbon atoms.
In this respect, repeating-ethylene oxide groups are a preferred chain lengthener, and it is believed that a slight increase in ductility is achieved as the length of the hydrophilic side chains is increased.
The lu~ricants used in the present invention, - therefore, can be characterized as esters, as are formed as for example, by the reaction of a fatty acid and a secondary amine, which secondary amine has two hydrophilic side chains each of which contains at least one OH group. These side chains are ; hydrophilic if they include at least one oxygen for every four - carbon atoms therein. In one embodiment o such materials the hydrophilic side chains may be increased in length by reacting the alcohol radicals with ethylene oxide, as is well known.
Because the lubricant molecules have an affinity for polymers, it is believed that the lubricant molecules migrate away from the surface of the glass and diffuse throughout the laminating ~olymer during molding and thereby allow the laminating polymer access to the surface of the glass couplings agents thereon.
It will, therefore, be seen that the lubricant used in the ~ ' ,.

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presen~ invention do a flip flop from the position and function which they provide in the wet condition of the fibers to that which they occupy and provide when fused to the matrix polymers.
It is highly unusual for a lubricant to actually increase the strength of the bond between a matrix polymer and glass fibers, and the lubricants used in the present invention are capable of accomplishing this result with any matrix resin, be it thermo-plastic or thermosetting. What is more, increased s~rength is provided whether or not a glass coupling agent is used, but in the preferred embodiments where the highest strength is desired, glass coupling agents of the silane type, and particularly the cationic silanes containing one organo group with nitrogen therein, will be used. The amount of the silanes used is not critical, since the effectiveness increases generally proportionately with the amount used until amounts up to approximately 5% of khe coating size are included.
Preferred size formulations will generally comprise the following materials in parts by weight:
- Materials Parts by Weight 20 Film forming polymer 2 - 12 r Silane glass coupling agent 0.1 - 5.~
Cationic lubricant as defined above0.1 - 5.0 Water 78 - 97.8 Preferred film formers to be used in the sizes of the present invention are epoxy polymers, particularly of the bisphenol A type, and the polyurethanes. Residual oxirane groups of the epoxies are capable of achieving good bond with the OH
groups of the lubricant and are catalyzed by the amine nitrogen.
What is more, they have good glass wetting properties. In this

3~ respect, the benzene rings of the bis-phenol A are beneficial.

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~96~5Z4 The urethanes, if any isocyanate groups remain, are also capable of reacting with OH groups of the lubricant and are also cationic and have good glass wet out properties. As pointed out above, polyesters can be used since they çontain polar oxygen either as ester groups or as acids or hydro~yl groups.
Where the size formulations are to coat glass that is to reinforce nylon, the following formulations are found to be most beneficial:
- Materials Parts by Weight Epoxy emulsion solids 5.0 - 12.0 Polyurethane latex solids 0 - 7.0 Silane glass coupling agent 0.1 - 5.0 Lubricant described above 0.1 - 5.0 Water Balance A specific noteworthy formulation is:
Materials - Parts by Weight Emulsified particles of a 7.00 Bisphenol A type epoxy film former Polyurethane film former 0.50 20 Gamma-aminopropyltrialkoxysilane 1.40 Cationic lubricant 0.50 Having described the invention in considerable detail, ~ I do not wish to be limited to the particular embodiments shown ; and described, and it is my intention to cover hereby all novel adaptations, modifications, and arrangements thereof which come within the practice of those skilled in the art to which ; the invention relates.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OF PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An aqueous size composition for coating glass fibers for reinforcing a nylon polymer, said size comprising the following solids in parts by weight:

Emulsified particles of an epoxy film former 5.0 - 12.0 Polyurethane 0.5 - 7.0 Silane glass coupling agent 0.1 - 5.0 Cationic lubricant 0.1 - 5.0 wherein said cationic lubricant is the reaction product of a fatty acid and a secondary amine having two organo side chains each of which have a carbon to oxygen ratio of no more than 4 to 1 and each of which includes at least one OH group.

2. The size of claim 1 comprising the following solids in approximate parts by weight:

Emulsified particles of a Bisphenol A type epoxy film former 7.00 Polyurethane film former 0.50 Gamma-aminopropyltrialkoxysilane 1.40 Cationic lubricant 0.50 wherein said cationic lubricant is the reaction product of a fatty acid and a secondary amine having two organo side chains each of which have a carbon to oxygen ratio of no more than 4 to 1 and each of which includes at least one OH group.

3. Glass fibers having a coating thereon comprising the following solids in the following approximate parts by weight:

Emulsified particles of an epoxy film former 5.0 - 12.0 Polyurethane 0.5 - 7.0 Silane glass coupling agent 0.1 - 5.0 Cationic lubricant 0.1 - 5.0 wherein said cationic lubricant is the reaction product of a fatty acid and a secondary amine having two organo side chains each of which have a carbon to oxygen ratio of no more than 4 to 1 and each of which includes at least one OH group.

4. The fibers of claim 3 wherein said coating comprises the following solids in approximate parts by weight:

Emulsified particles of a Bisphenol A type epoxy film former 7.00 Polyurethane film former 0.50 Gamma-aminopropyltrialkoxysilane 1.40 Cationic lubricant 0.50 wherein said cationic lubricant is the reaction product of a fatty acid and a secondary amine having two organo side chains each of which have a carbon to oxygen ratio of no more than 4 to 1 and each of which includes at least one OH group.

5. A glass fiber reinforced plastic article wherein the glass fibers have a coating of the following solids in the following parts by weight:

Emulsified particles of epoxy film former 5.0 - 12.0 Polyurethane 0.5 - 7.0 Silane glass coupling agent 0.1 - 5.0 Cationic lubricant 0.1 - 5.0 wherein said cationic lubricant is the reaction product of a fatty acid and a secondary amine having two organo side chains each of which have a carbon to oxygen ratio of no more than 4 to 1 and each of which includes at least one OH group.

6. The reinforced plastic article of claim 5 wherein the plastic is a nylon.

7. The reinforced plastic article of claim 5 wherein the plastic is a polycarbonate.

8. The reinforced plastic article of claim 5 wherein the cationic lubricant is the reaction product of a dialkanol amine and a fatty acid.

9. The reinforced plastic article of claim 8 wherein the plastic is a nylon.

10. The reinforced plastic article of claim 8 wherein the plastic is a polycarbonate.