WO1994013473A1

WO1994013473A1 - Chemical treatment for glass fibers

Info

Publication number: WO1994013473A1
Application number: PCT/US1993/011722
Authority: WO
Inventors: Michael W. Klett
Original assignee: Ppg Industries, Inc.
Priority date: 1992-12-04
Filing date: 1993-12-03
Publication date: 1994-06-23
Also published as: AU5737194A

Abstract

An aqueous sizing for reinforced glass fibers provides improved processing properties, shear strength and compatibility with phenolic resin reinforcers. The coated, reinforced glass fibers are useful in filament winding and pultrusion wherein the coating is an aqueous sizing comprising a ureido-modified amino silane coupling agent and a polyvinyl pyrrolidone film-former. The sizing is free of epichlorohydrin-polyamide reaction products and vinyl aromatic monomer-maleic anhydride copolymers.

Description

CHEMICAL TREATMENT FOR GLASS FIBERS

BACKGROUND OF THE INVENTION This invention is directed to chemical treatments, called sizings, for glass fibers which are to be incorporated into resin systems for use as reinforcement or as a solid article.

Fibers, particularly glass fibers, are useful as reinforcement in a number of different applications such as described in the Fiberglass-Reinforced Plastics Deskbook by Nicholas P. Cheremisinoff and Paul N. Cheremisinoff, Ann Arbor Science Publishers, Inc., 1979, Library of Congress Catalog Card Number 78-62293. In combining glass fibers with various resins, it is important that the fibers have good processing properties like low fuzz production and good wet- out and wet-through. It is also important that the resulting product have high mechanical properties, particularly high shear strength.

One application of glass fibers is in filament winding. In filament winding, continuous glass fibers impregnated with resin are wound around a steel mandrel until a desired thickness is reached. The resin used depends on the properties desired in the end product, and the sizing for the glass fibers depends on the resin system which is used. Useful resins for this process are the liquid phenolic resins.

Another use for glass fibers is in the process of pultrusion. In pultrusion, a plurality of glass fibers are pulled through a heated die where they are combined with resin. As the resin and glass pass through the die, the heat cures the resin thereby forming a solid article. A common example of a pultruded article is the side rail of step ladders. These are easily recognizable since they are generally a bright color, like orange. Liquid phenolic resins are also particularly useful in pultrusion processes.

It is an object of this invention to provide sized fibers which provide desirable processing and mechanical properties in pultrusion and filament winding applications, and that show good compatibility with phenolic resins.

SUMMARY OF THE INVENTION The objects of the invention are achieved by glass fibers having thereon a sizing which is applied in an aqueous state and then dried. This sizing has, in addition to water, a ureido modified amino silane coupling agent, a polyvinyl pyrrolidone film former, and a cationic lubricant. The sizing may optionally have additional silane coupling agents, lubricants, film formers and plasticizers though it is preferred that the sizing be essentially free of components such as epichlorohydrin polyamide reaction products or copolymers of a vinyl aromatic monomer and maleic anhydride.

DETAILED DESCRIPTION OF THE INVENTION

Glass fibers employed in the invention may be those such as "E glass", "S glass", "D glass" or any of the glasses known in the art. Typical formulations of such glass fibers are disclosed in The Manufacturing Technology of Continuous Glass Fibres. Library of Congress Catalog Card Number 72-97429, by K. L. Loewenstein, Elsevier Scientific Publishing, 1973, at page 29.

The aqueous sizing composition is applied by sprayers, rollers, belts, or the like. The sized glass fibers are gathered into bundles comprising a plurality of individual fibers, generally from 200 to more than 3000. The bundles are usually wound onto a forming package and the sizing is dried at room temperature or by oven heating for a time and at a temperature which will remove the moisture from the fibers. The preferred time/temperature relationship for the sizing of this invention is about 285°F (141°C) for about 10 hours. The sized glass fibers generally have between about 0.05 and 5 percent of sizing composition based on the weight of the glass fiber.

The sizing of this invention can have, in addition to water, 10 to 35 weight percent on a non-aqueous basis of ureido modified amino silane coupling agent, 25 to 70 weight percent on a non-aqueous basis of polyvinyl pyrrolidone homopolymer film former, and 5 to 25 weight percent on a non- aqueous basis of cationic lubricant. The sizing may also have 0 to 15 weight percent on a non-aqueous basis of additional silane coupling agents (though preferably the amount of additional silane present is greater than zero) such as amino functional and epoxy functional silanes. The sizing may also have other lubricants and film formers, and ^'0 to 35 weight percent on a non-aqueous basis of plasticizers (though preferably the amount of plasticizer present is greater than zero) for the polyvinyl pyrrolidone film former, provided, however, that there be at least one part polyvinyl pyrrolidone to each part plasticizer on a weight basis.

By "ureido modified silane" is meant the novel ureido functional silanes of U.S. Patents Nos. 3,754,971 and 4,626,560 or an amino functional silane of the following general formula:

X-C- (Z) z-N- (CH2)χ-Si- (O-Ri) 3-y

H Ay ⁽CH2⁾v / \ wherein; X is -N-R2 -N C=0 or -0- (CH2)_W-CH3

R3

Z is -R₄-N-R5.

H

Rl» R2 R3 R4 and R5 may each independently be

H, or an alkyl group;

A is an alkyl or alkoxide group; v is an integer from 1 to 10, w is an integer from 0 to 10, x is an integer from 1 to 10, y is an integer from 0 to 3; z is either 0 or 1; and Si is a silane atom, C a carbon atom, O an oxygen atom, N a nitrogen atom and H a hydrogen atom.

The preferred silane is defined by the formula: O

H-N-C-N- (CH2)3-Si- (0-CH2CH3)3

I I H H

which is sold in a 50 percent solution in methanol as A-1160 by Union Carbide Corporation. Such silanes may be used in the unhydrolyzed, partially hydrolyzed or hydrolyzed form. Hydrolysis of silanes is accomplished by contact with organic acid, preferably acetic acid. Polyvinyl pyrrolidone is the main film former though additional film formers may be used which are water soluble, dispersible or emulsifiable, such as starches and polyvinyl alcohols .

Starches which may be used include amylose-containing starches and starch mixtures derived from any starch sources including corn, wheat, potato, tapioca, waxy maize, sago, rice, hybrid starches, etc. Conventionally, however, the starch components having a high amylose content, e.g. 50 to 60 percent by weight, are derived from either corn starch or a hybrid corn starch. The starch components having a low amylose content, e.g. 20 to 30 percent by weight are usually derived from either potato or derivatized corn starch, such as cationic, phosphatized, ethoxylated or etherified derivatives. The overall amylose content of a starch mixture can vary from about 35 to about 55 percent by weight based on the total starch content.

Examples of suitable starches are those of U.S. Patent Nos. 3,227,192; 3,265,516; and 3,887,389. An example of commercially available starches which may be suitable for this invention are "Hylon" , sold by National Starch and Chemical Co., and "Amaizo 2213" sold by American Maize Products Company.

Polyvinyl pyrrolidone is the key film former. By the term "polyvinyl pyrrolidone" is meant any homopolymer obtained by the addition polymerization of a monomer which may be represented by the formula:

R²HC- ^•C--R<

R^-HC C=0

\ /

N

I CH=CH2 wherein Rl, R2, R3 and R4 may each be hydrogen or lower alkyls. Examples of such monomers include N-vinyl-2- pyrrolidone, 5-methyl-N-vinyl-2-pyrrolidone, 4-methyl-N-vinyl-2-pyrrolidone, 5-ethyl-N-vinyl-2- pyrrolidone, 4-ethyl-N-vinyl-2-pyrrolidone, 3-methyl-N-vinyl-2-pyrrolidone, 3-ethyl-N-vinyl-2- p rrolidone, 3,3-dimethyl-N-vinyl-2-pyrrolidone, 3, 5-dimethyl-N-vinyl-2-pyrrolidone and the like. These monomers and their homopolymerization products are known in the art. It is preferred that the polyvinyl pyrrolidone have an average molecular weight of from about 5000 to 100,000. Suitable polyvinyl pyrrolidones produced by the polymerization of N-vinyl-2-pyrrolidone are available from International Specialty Products under the trade designations PVP K-15, PVP K--0, PVP K-60 and PVP K-90 wherein the K-value identifies the viscosity grade. The number average of the molecular weights for these grades is about 10,000, 40,000, 160,000 and 360,000, respectively. A plasticizer may also be present for the polyvinyl pyrrolidone film former. Examples of suitable plasticizers for polyvinyl pyrrolidone are carboxymethylcellulose, cellulose acetate, polyoxyalkylene glycols, glycerin, dimethyl phthalate, diethylene glycol, dibutyl tartrate, and polyalkylene glycols. The preferred plasticizer is polyethylene glycol, examples of which are available from Union Carbide Corporation under the product designations Carbowax 300 and Carbowax 400 having approximate molecular weights of 300,000 and 400,000, respectively. While essentially any cationic lubricant known in the art may be used, the preferred cationic lubricants are alkyl imidazoline derivatives. These include compounds of the class n-alkyl-N-amido-alkyl imidazolines, which may be formed by causing fatty acids or carboxylic acids to react with polyalkylene polyamines under conditions which produce ring closure. The reaction of tetraethylene-pentamine with stearic acid is exemplary of such a reaction and the product is available under the name Cation-X^® from Lyndal Chemical Co. These imidazolines are described in U.S. Patent No. 2,200,815 and other imidazolines are described in U.S. Patent Nos. 2,267,965; 2,268,273; and 2,353,837.

Other cationic lubricants which may be used alone or in combination with the alkyl imidazoline derivative include a polyamino functional polyamide resin formed normally by the condensation reaction of a polycarboxylic acid such as tetraethylene pentamine, ethylene triamine, diethylene triamine, diethylenetetramine and the like. One such resin is Versamid 140 which has an amine value of 370 to 400 and is available from General Mills. Another useful cationic lubricant is the partially amidated polyamine having the trade designation Emery^® 6717 available from Henkel Corp. Additional silane coupling agents may be included in the sizing utilized in this invention and include amino functional silanes like those having the formula NH2-R2-Si (ORi) z where z is an integer from 1 to 3. Ri can be the same or different moieties selected from lower alkyl or aliphatic hydrocarbons having less than eight and preferably less than 5 carbon atoms, and R2 is a difunctional radical selected form the lower alkyl or aliphatic hydrocarbons having less that eight carbon atoms . The corresponding hydrolysis products can also be employed, such as the corresponding silanols and/or polysiloxanes . Amino functional silanes of the general type gamma- aminoalkyltrialkoxy silane may be used. Examples of such additional silane coupling agents include gamma- aminopropyltriethoxy silanes such as those commercially available from Union Carbide Corporation under the trade designation A-1100 silane coupling agent and A-1108 amino silane coupling agent which is modified with a lubricant. Epoxy functional silanes of the general type gamma- glycidoxyalklytrialkoxy silane such as gamma-glycidoxypropyltrimethoxy silane, commercially available as Union Carbide's A-187, are also useful.

While other ingredients may be added to the composition of this invention, the sizing is essentially free of epichlorohydrin polyamide reaction products and copolymerε of a vinyl aromatic monomer and maleic anhydride.

The resin which may be used with fibers sized" as disclosed above are those of the liquid phenolic type. By "liquid phenolic" resins what is meant is those resins which are formed by the condensation reaction of phenols and aldehydes. Such resins are well known in the art and are described in Polymer Synthesis, by Stanley R. Sandier and Wolf Karo, volume II, chapter 2, by Academic Press, Inc., New York, NY., 1977, Library of Congress Catalog Card Number 73-2073, which is part of the series Organic Chemistry: A Series of Monographs. Volume 29. In the condensation reaction, in addition to phenol, other phenols such as o-cresol, mixed cresols, p-tert-butylphenol, p-phenylphenol, resorcinol and cardanol may be used. Aldehydes such as formaldehyde and furfural may be used.

Examples of sizings according to this invention are shown in Table I and all of the ingredients appearing in Table I have been described above. Table I

Units are grams per gallon and percentages are by weight on a non-aqueous basis.

The preparation of sizings is well known in the art and the procedure which follows is one example of the several appropriate procedures which can be employed. The procedure for preparing the above sizings is similar and the following illustrates the preparation of example A above. 1200 grams of hot (120-160°F or 49-71°C) water were added to a main mix tank; the polyvinyl pyrrolidone was slowly added to the main mix tank with stirring; Carbowax 300 polyethylene glycol was dissolved in hot water and added to the main mix tank; 1000 grams of hot water were added to a second tank; 29 grams of A-1100 silane and 53 grams of A-1160 silane were added to the second tank with stirring and then transferred to the main mix tank; Cation-X^® lubricant was dispersed in hot water and then added to the main mix tank. Fibers sized with the solution of example C were pultruded with a liquid phenolic resin. The fibers were E-glass of "K" diameter or approximately 13 microns in diameter. The fibers were sized using a roller applicator and were dried in an oven at 285°F (141°C) for 10 hours. The liquid phenolic resin used was a mixture of 74 percent resorcinol-formaldehyde resin and 26 percent phenol/polymer with paraformaldehyde (phenol-formaldehyde condensate) . Both resin products are sold commercially by Indspec Chemical Corporation of Pittsburgh, PA and are designated Resorciphen™ 2026-B resin and Resorciphen™ 2074-A resin respectively. The pultrusion die was maintained at a temperature of about 375-400°F (195-205°C) and the glass fibers and resin moved at about 12 inches (305 cm) per minute through the die. The final product had about 72-75 weight percent glass. The product had a short beam shear strength according to ASTM test No. D-2344 of 5.45 Kpsi and a flexural strength according to ASTM test No. D-790 of 128.8 Kpsi.

Fibers sized with the solution of example A were filament wound with liquid phenolic resin. The fibers were E-glass of "T" diameter or about 23.5 microns. The fibers were sized and dried as described above. The resin was a mixture of phenol-formaldehyde types produced by Indspec Chemical Corporation under the trade designations PRF2 1000 and PRF2 1030FM. The glass fibers with the resin were filament wound in the manner known in the art at a 54° wind angle to produce a 2 inch (51 cm) diameter pipe with a wall thickness of 0.1 inches (2.5 mm) using three complete layers of glass fibers which had a yield of 250 yards/lb. The pipe was cured by heating for 2 hours at between 70 and 80°C and then for 90 minutes at 90°C. The same procedure was used to produce a similar pipe using the same resin but using a different, commercially available, competitive glass fiber. The commercially available glass was E-glass of approximately 23 microns in diameter. Both pipe samples were subjected to destructive crush testing to determine the point of failure. The competitive glass fiber pipe failed at a load of 262 pounds while the pipe made with the fibers sized according to example A failed at a load of 393 pounds, or about 50 percent greater.

Claims

I claim :

1. A glass fiber coated with a dried residue of an aqueous sizing, where the sizing comprises: (a) an unhydrolyzed, partially hydrolyzed or hydrolyzed ureido modified amino silane coupling agent;

(b) a polyvinyl pyrrolidone homopolymer film former; (c) at least one cationic lubricant;

(d) water in an amount to provide an aqueous solution for coating the fiber wherein the sizing is essentially free of epichlorohydrin polyamide reaction products and copolymers of a vinyl aromatic monomer and maleic anhydride.

2. The glass fiber of claim 1 further comprising a plasticizer in the aqueous sizing, provided, however, that there be at least one part polyvinyl pyrrolidone to each part plasticizer on a weight basis.

3. The glass fiber of claim 2 wherein the plasticizer is polyethylene glycol.

4. The glass fiber of claim 1 further comprising at least one additional silane in the aqueous sizing.

5. The glass fiber of claim 4 wherein the silane is selected from the group consisting of amino functional silanes and epoxy functional silanes and mixtures thereof.

6. The glass fiber of claim 4 wherein the silane is selected from the group consisting of gamma- glycidoxypropyltrimethoxysilane and gamma- aminopropyltriethoxysilane and mixtures thereof.

7. The glass fiber of claim 1 further comprising a polyamino functional polyamide resin in the aqueous sizing.

8. The glass fiber of claim 1 wherein the cationic lubricant is selected from the group consisting of alkyl imidazoline derivatives and fatty imidazoline derivatives of tetraethylene-pentamine and stearic acid.

9. A glass fiber coated with a dried residue^" of an aqueous sizing, where the sizing comprises:

(a) 10 to 35 weight percent on a non-aqueous basis of an unhydrolyzed, partially hydrolyzed or hydrolyzed ureido modified amino silane;

(b) 0 to 15 weight percent on a non-aqueous basis of silane selected from the group consisting of amino functional silanes and epoxy functional silanes and mixtures thereof;

(c) 5 to 25 weight percent on a non-aqueous basis of cationic lubricant selected from the group consisting of alkyl imidazoline derivatives and fatty imidazoline derivatives of tetraethylene-pentamine and stearic acid;

(d) 25 to 70 weight percent on a non-aqueous basis of polyvinyl pyrrolidone homopolymer film former; (e) 0 to 35 weight percent on a non-aqueous basis of polyethylene glycol, provided, however that there be at least one part polyvinyl pyrrolidone to each part polyethylene glycol on a weight basis, and;

(f) water in an amount to provide an aqueous solution for coating the fiber wherein the sizing is essentially free of epichlorohydrin polyamide reaction products and copolymers of a vinyl aromatic monomer and maleic anhydride.

10. A phenolic resin reinforcing fiber coated with a dried residue of an aqueous sizing composition, where the sizing composition comprises:

(a) an unhydrolyzed, partially hydrolyzed or hydrolyzed ureido modified amino silane coupling agent; (b) a polyvinyl pyrrolidone homopolymer film former;

(c) at least one cationic lubricant;

11. The phenolic resin reinforcing fiber of claim 10 further comprising a plasticizer in the aqueous sizing, provided, however, that there be at least one part polyvinyl pyrrolidone to each part plasticizer on a weight basis.

12. The phenolic resin reinforcing fiber of claim 11 wherein the plasticizer is polyethylene glycol.

13. The phenolic resin reinforcing fiber of claim 10 further comprising at least one additional silane in the aqueous sizing.

14. The phenolic resin reinforcing fiber of claim

13 wherein the silane is selected from the group consisting of amino functional silanes and epoxy functional silanes and mixtures thereof.

15. The phenolic resin reinforcing fiber of claim

13 wherein the silane is selected from the group consisting of gamma-glycidoxypropyltrimethoxysilane and gamma- aminopropyltriethoxysilane and mixtures thereof.

16. The phenolic resin reinforcing fiber of claim

10 further comprising a polyamino functional polyamide resin in the aqueous sizing.

17. The phenolic resin reinforcing fiber of claim 10 wherein the cationic lubricant is selected from the group consisting of alkyl imidazoline derivatives and fatty imidazoline derivatives of tetraethylene-pentamine and stearic acid.

18. A phenolic resin reinforcing glass fiber coated with a dried residue of an aqueous sizing, where the sizing comprises:

(c) 5 to 25 weight percent on a non-aqueous basis of cationic lubricant selected from the group consisting of alkyl imidazoline derivatives and fatty imidazoline derivatives of tetra¬ ethylene-pentamine and stearic acid;

(d) 25 to 70 weight percent on a non-aqueous basis of polyvinyl pyrrolidone homopolymer film former;

(e) 0 to 35 weight percent on a non-aqueous basis of polyethylene glycol, provided, however that there be at least one part polyvinyl pyrrolidone to each part polyethylene glycol on a weight basis, and;

19. A phenolic resin reinforcing glass fiber coated with a dried residue of an aqueous sizing, where the sizing comprises : (a) 15 to 25 weight percent on a non-aqueous basis of an unhydrolyzed, partially hydrolyzed or hydrolyzed ureido modified amino silane;

(b) 5 to 15 weight percent on a non-aqueous basis of silane selected from the group consisting of amino functional silanes and epoxy functional silanes and mixtures thereof; (c) 5 to 15 weight percent on a non-aqueous basis of cationic lubricant selected from the group consisting of alkyl imidazoline derivatives and fatty imidazoline derivatives of tetra- ethylene-pentamine and stearic acid;

(d) 25 to 50 weight percent on a non-aqueous basis of polyvinyl pyrrolidone ho opolymer film former;

(e) 20 to 35 weight percent on a non- aqueous basis of polyethylene glycol, provided, however that there be at least one part polyvinyl pyrrolidone to each part polyethylene glycol on a weight basis, and;

20. A phenolic resin reinforcing glass fiber coated with a dried residue of an aqueous sizing, where the sizing comprises:

(a) 15 to 25 weight percent on a non-aqueous basis of an unhydrolyzed, partially hydrolyzed or hydrolyzed ureido modified amino silane;

(b) 5 to 15 weight percent on a non-aqueous basis of silane selected from the group consisting of gamma-aminopropyltriethoxy-silane and gamma- glycidoxypropyltri-methoxysilane and mixtures thereof;

(c) 5 to 15 weight percent on a non-aqueous basis of cationic lubricant selected from the group consisting of alkyl imidazoline derivatives and fatty imidazoline derivatives of tetra¬ ethylene-pentamine and stearic acid;

(d) 25 to 50 weight percent on a non-aqueous basis of polyvinyl pyrrolidone homopolymer film former;

(e) 20 to 35 weight percent on a non-aqueous basis of polyethylene glycol, provided, however that there be at least one part polyvinyl pyrrolidone to each part polyethylene glycol on a weight basis, and;