Coating compositions, coated glass fibers and composites reinforced with the glass fibers

Abstract

Sizing/finishing composition comprising poly(hydroxy amino ether), and a solubilizing/emulsifying agent present in an amount sufficient to solubilize or emulsify the polymer in water.

Description

BACKGROUND OF THE INVENTION

[0002] The present invention relates to coating compositions, coated glass fibers and composites reinforced with the glass fibers.

[0003] Glass fibers are produced by flowing molten glass via gravity through a multitude of small openings in a precious metal device, called a bushing. Typical formulations of 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. Glass fibers are, for example, those known as “E glass”, “S glass”,“D glass” and are typically between 3 and 30 microns in diameter.

[0004] After the fibers have cooled very shortly after their issuance from the bushing and usually in close proximity to the bushing, these fibers are treated with a chemical treating formulation usually referred to in the art as a “sizing composition” or “size”. The size serves to make the fibers more compatible with the material they will ultimately be used to reinforce and to make the fibers more easy to process. The aqueous size can be applied by sprayers, rollers, belts, metering devices or any similar application device. The sized glass fibers are gathered into bundles or strands comprising a plurality of individual fibers, generally from 200 to more than 3000. The sized glass fibers generally can have between about 0.01 and 5 percent of sizing composition based on the weight of the glass fiber.

[0005] After their formation and treatment, the strands can be wound into a spool or “forming package” and/or may be chopped. The forming packages or chopped strands are usually dried in either an oven or at room temperature to remove some of the moisture from the fibers.

SUMMARY OF THE INVENTION

[0006] In a first aspect, the present invention is a coating composition comprising a poly(hydroxy amino ether), and a solubilizing/emulsifying agent present in an amount sufficient to solubilize or emulsify the polymer in water.

[0007] In a second aspect, the present invention is a glass fiber coated with the coating composition of the first aspect.

[0008] In a third aspect, the present invention is a composite reinforced with the glass fiber of the second aspect.

DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferably, the poly(hydroxy amino ether) has repeating units represented by the formula: 1

[0010] wherein A is a diamino moiety or a combination of different amine moieties; B is a divalent organic moiety which is predominantly hydrocarbylene; R is hydrogen or alkyl; and m is an integer from 5 to 1000.

[0011] The solubilizing/emulsifying agents which can be used in the practice of the present invention include mineral acids such as sulfuric acid, and carboxylic acids, such as acetic acid, glycolic acid, citric acid, and lactic acid.

[0012] Any of the emulsifying agents described in The Manufacturing Technology of Continuous Glass Fibres, Library of Congress Catalog Card Number 72-97429, by K. L. Loewenstein, Elsevier Scientific Publishing, 1983, at page 278) that are compatible with polyhydroxyaminoethers can be used.

[0013] The solubilizing/emulsifying agent is employed in an amount sufficient to emulsify or solubilize the polymer in water but, in general, it is employed in an amount of from -0- to -200-, preferably, from -10- to -100- and, most preferably, -30 to 50- weight percent of the coating composition on a total solids basis.

[0014] The coating compositions may include conventional coupling agents, lubricating agents and antifoam agents as well.

[0015] The coupling agents, lubricating agents and antifoam agents can be added to the coating composition by methods well known in the art and described in The Manufacturing Technology of Continuous Glass Fibres, Library of Congress Catalog Card Number 72-97429, by K. L. Loewenstein, Elsevier Scientific Publishing.

[0016] The coupling agents can also be incorporated into the backbone of the hydroxy functionalized polyethers.

[0017] The coupling agents which can be employed in the practice of the present invention include organo silane coupling agents, transition metal coupling agents, phosphonate coupling agents, aluminum coupling agents, titanate coupling agents, zirconate coupling agents, chromium complexes coupling agents, amino-containing Werner coupling agents and titanate coupling agents and mixtures thereof. Examples of organo silanes include amino silanes, epoxy silanes, cyanates silanes, isocyanato silanes and ureido silanes.

[0018] These coupling agents typically have dual functionality. Each metal or silicon atom has attached to it one or more groups which can react or compatibilize with the fiber surface and/or the components of the aqueous sizing composition. As used herein, the term “compatibilize” means that the groups are chemically attracted, but not bonded, to the fiber surface and/or the components of the sizing composition, for example by polar, wetting or salvation forces.

[0019] Functional organo silane coupling agents are preferred for use in the present invention. Examples of useful functional organo silane coupling agents include gamma-aminopropyltrialkoxysilanes, gamma-isocyanatopropyltriethoxysilane, vinyl-trialkoxysilanes, glycidoxypropyltrialkoxysilanes and ureidopropyltrialkoxysilanes. Preferred functional organo silane coupling agents include A-187 gamma-glycidoxy-propyltrimethoxysilane, A-174 gamma-methacryloxypropyltrimethoxysilane, A-1100 gamma-aminopropyltriethoxysilane silane coupling agents, A-1108 amino silane coupling agent and A-1160 gamma-ureidopropyltriethoxysilane (each of which are commercially available from OSi Specialties, Inc. of Tarrytown, N.Y.). The organo silane coupling agent can be at least partially hydrolyzed with water prior to application to the fibers, preferably at about a 1:1 stoichiometric ratio or, if desired, applied in unhydrolyzed form.

[0020] Suitable transition metal coupling agents include titanium, zirconium, yttrium and chromium coupling agents.

[0021] Suitable titanate coupling agents and zirconate coupling agents are commercially available from Kenrich Petrochemical Company. Suitable chromium complexes are commercially available from E.I. DuPont de Nemours of Wilmington, Del. The amino-containing Werner-type coupling agents are complex compounds in which a trivalent nuclear atom such as chromium is coordinated with an organic acid having amino functionality. Other metal chelate and coordinate type coupling agents known to those skilled in the art can be used herein.

[0022] The amount of coupling agent can range from about 0 to about 20 weight percent, and preferably from about 0 to about 10 weight percent of the coating composition on a total solids basis.

[0023] The lubricating agents which can be employed in the practice of the present invention include block copolymers of ethylene oxide and propylene oxide and polyetyleneimine polyamide salt.

[0024] The amount of lubricating agent can range from about 0 to about 20 weight percent and, preferably, from about 0 to about 10 weight percent of the coating composition on a total solids basis.

[0025] The antifoam agents which can be employed in the practice of the present invention include polydimethysiloxane. Any other antifoam agent that is compatible with the formulation can be used.

[0026] The amount of antifoam agent can range from about 0 to about 10 weight percent of the coating composition on a total solids basis, and preferably from about 0 to about 5 weight percent.

[0027] The hydroxy functionalized ethers can be easily modified by methods well known in the art to improve its compatiblity with a wide range of polymeric and resinous materials. Such methods include, for example, melt blending of a suitable anhydride with the polyhydroxyaminoether.

[0028] The coating compositions described in this invention can be used as “sizing composition” where the composition is applied to fibers as fibers come out of the bushing, as “finishing composition” where the composition is applied after performing secondary operation on the fibers such as weaving, and as “binding composition” where the composition is applied to form veils and mat out of non-woven fibers.

[0029] The coating composition of the present invention can also be used to bind fibers that are already treated with a suitable sizing agents so as to assist the formation of near net shape preforms. The compositions of the present invention can also be used to treat carbon fibers.

[0030] The following examples are given to illustrate the invention and should not be construed as limiting its scope. All parts and percentages are by weight unless otherwise indicated.

EXAMPLE 1

[0031] A. Preparation of Adhesion Promoter

[0032] A polyhydroxyaminoether solution was prepared by mixing 4 grams of BLOX™ 205, a 5 Melt Index polyhydroxyaminoether commercially available from The Dow Chemical Company, and 196 grams of 2% acetic acid solution.

[0033] B. Measuring the Effectiveness of the Adhesion Promoter

[0034] (a) Preparation of Test Samples

[0035] The top adherend (glass plate) was immersed in 1% solution of 3-aminopropyltriethoxysilane (APS) in 95% methanol/5% deionized water for 2-3 minutes. The solution was obtained from Aldrich Chemical. The treated glass was dipped into methanol bath to rinse off excess coupling agent. The glass plate was then air dried for 10 minutes and placed in a 110° C. oven for 8 minutes.

[0036] The bottom adherend (glass plate) was first baked in an oven at 120° C. for 1 hour to make sure that glass is free of moisture. The glass was then transferred to vacuum desiccators where samples were kept until use time. The glass was soaked with the adhesion promoter prepared in Part A above for 2-3 minutes and then air dried for 10 minutes. The glass plate was then placed in an oven at 110° C. for 8 minutes. The oven temperature was ramped to 160° C. and maintained at this temperature for 5 minutes. In order to create a weaker interface for crack initiation, an 11 mm×17 mm area on the glass was sputter-coated with Au/Pd.

[0037] The bottom plate along with shims was placed in a silicone mold. A bead of epoxy resin (96% Bisphenol F epoxy resin (EPON® Resin 862 from Shell Chemical Company) and 4% imidazole curing agent (IMICURE® EMI-24 from Air Products) was placed on the bottom plate. The APS coated glass plate was placed on the top and was allowed to settle under its own weight for a few minutes before it was gently pressed against the shims to squeeze out excess resin and any trapped air. The epoxy was cured by placing the mold in an oven at 60° C. for 4 hours and then post cured at 150° C. for 2 hours.

[0038] The sample was then cooled to room temperature. Excess epoxy was removed from the edges by grinding. The sample edges were then polished with 6 micron diamond. A started crack was created on the Au/Pd coated end of the bottom plate by using a Jeweler's saw (a small saw used by Jewelers). Aluminum stubs were glued to the Au/Pd side of the bottom plate using Loctite Superbonder 409 (superadhesive from Loctite Corporation, 1001 Trout Brook Crossing Rocky Hill, Conn. 06067).

[0039] The samples were aged in a humidity-controlled chamber (85° C./85% RH).

[0040] (b) Double Cantilever Beam (DCB) Test

[0041] The Double Cantilever Beam (DCB) test was performed on the aged samples using a screw driven Instron testing machine at a loading rate of 0.127 mm/min. If a test sample did not fail when the loading force reached 250N, the testing was stopped and the test sample was returned to the aging chamber. The samples were tested after 4, 7, 14, 21 days. In the cases were the pre-crack did advance, the critical interfacial strain energy release rate (Gc) was measured. The samples were fractured completely when critical strain energy release rate is measured. The results are analyzed in terms of days until Gc can be measured.

[0042] Four test samples were prepared using this procedure. Three out of four test samples did not fail under a loading of 250 N after seven days of aging at 85° C. and 85% relative humidity. However, these three specimens failed after 14 days of aging at 85° C. and 85% relative humidity.

Example 2

[0043] Four test samples were prepared as in Example 1 except that no adhesion promoter was applied to the bottom plate. The adhesion effectiveness was tested according to the procedure described in Example 1, Part B. All four samples failed when subjected to a loading of 250 N after they were aged at 85° C. and 85% relative humidity for 4 days.

[0044] A comparison of the results in this example with those in Example 1B shows that the polyhydroxyaminoethers significantly enhanced the adhesion to glass under the humid environment

EXAMPLE 3

[0045] Modified BLOX 220, a 20 Melt Index polyhydroxyaminoether resin commercially available from The Dow Chemical Company, was prepared by mixing 0.4 gms of maleic anhydride (MAH) with 39.6 gms BLOX 220 in HAAKE™ mixer for 2 minutes. The initial temperature was 110° C. and the final temperature was 135° C. Four grams of this modified polyhydroxyaminoether was dissolved in 196 gms of 2% acetic acid solution. The solution was used as adhesion promoter according to the procedure used in Example 1B.

[0046] Three out of four test samples did not fail under a loading of 250 N after 14 days of aging at 85° C. and 85% relative humidity. Two out of four test samples did not fail under a loading of 250 N after 21 days of aging at 85° C. and 85% relative humidity.

[0047] Compared to Example 1B, the modified BLOX made in this example significantly enhanced the adhesion of glass under humid environment. Compared to Example 2, the modified BLOX improved the adhesion even better than the BLOX itself.

EXAMPLE 4

[0048] A polyhydroxyaminoether solution was prepared by mixing 4 grams of BLOX 205, and 196 grams of 2% malic acid solution.

[0049] The solution was mixed in a 90:10 ratio with APS solution obtained from Aldrich Chemical Company (the APS solution contained 1% solution of 3-aminopropyltriethoxysilane in 95% methanol/5% deionized water). The mixture of polyhydroxyaminoether solution and APS solution was used as adhesion promoter according to the procedure used in Example 1B. Three out of four test samples did not fail after 21 days of aging at 85° C. and 85% relative humidity.

[0050] The results in this example show that the conventional coupling agents such as organo silanes can be used to further improve the adhesion to glass under humid environments.

EXAMPLE 5

[0051] BLOX 220 was modified by mixing 0.4 gms of maleic anhydride (MAH) with 39.6 gms BLOX 220 in HAAKE™ mixer for 2 minutes. The initial temperature was 100° C. and the final temperature was 125° C. The material was then dissolved in acetic acid to obtain a 25% solution. The solution was poured into an aluminum pan. The pan was kept in a vacuum oven at 6° C. until a solid film was obtained. The pan was cooled to room temperature and catalyzed vinyl ester resin (DERAKANE™ 411-350, a product of The Dow Chemical Company) was poured on top of the film. The vinyl ester was allowed to cure at room temperature and then post cured at 120° C. for 2 hours. The film of MAH-modified BLOX resin was firmly attached to the vinyl ester films and could not be separated. The result of this example demonstrates that modified BLOX will have good adhesion with the vinyl ester resins.

Claims

1. A coating composition comprising poly(hydroxy amino ether) and a solubilizing/emulsifying agent present in an amount sufficient to solubilize or emulsify the polymer in water.

2. The coating composition of claim 1 wherein the poly(hydroxy amino ether) has repeating units represented by the formula:

3. The coating composition of claim 1 wherein the solubilizing/emulsifying agent is a mineral acid.

4. The coating composition of claim 3 wherein the mineral acid is phosphoric acid or sulfuric acid.

5. The coating composition of claim 1 wherein the solubilizing/emulsifying agent is carboxylic acid.

6. The coating composition of claim 5 wherein the carboxylic acid is acetic acid, glycolic acid, citric acid, or lactic acid.

7. The coating composition of claim 1 wherein the solubilizing/emulsifying agent is present in an amount of from about 20 to about 60 of the coating composition on a total solids basis.

8. The coating composition of claim 1 further comprising a coupling agent, lubricating agent and/or antifoam.

9. The coating composition of claim 8 wherein the coupling agent is an organo silane coupling agent, transition metal coupling agent, phosphonate coupling agent, aluminum coupling agent, titanate coupling agent, zirconate coupling agent, chromium complexes coupling agent, amino-containing Werner coupling agent or titanate coupling agent or mixtures thereof.

10. The coating composition of claim 8 wherein the coupling agent is present in an amount of from about 0 to about 20 weight percent of the coating composition on a total solids basis.

11. The coating composition of claim 8 wherein the lubricating agent is a block copolymer of ethylene oxide and propylene oxide or a polyetyleneimine or polyamide salt.

12. The coating composition of claim 8 wherein the lubricating agent is present in an amount of from about 0 to about 20 weight percent of the coating composition on a total solids basis.

13. The coating composition of claim 8 wherein the antifoam agent is polydimethysiloxane.

14. The coating composition of claim 8 wherein the antifoam agent is present in an amount of from about 0 to about 10 weight percent of the coating composition on a total solids basis.

15. Glass fibers coated with a coating composition comprising poly(hydroxy amino ether) and a solubilizing/emulsifying agent present in an amount sufficient to emulsify or solubilize the polymer in water.

16. Composites reinforced with the glass fibers of claim 15.

17. Carbon fibers coated with a coating composition comprising poly(hydroxy amino ether) and a solubilizing/emulsifying agent present in an amount sufficient to emulsify or solubilize the polymer in water.

18. Composites reinforced with the carbon fibers of claim 17.