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GLASS FIBER REINFORCED ELASTOMERS
This is a division of application Ser. No. 98,813, filed Dec. 16, 1970, now U.S. Pat. No. 3,705,075.
This invention relates to elastomeric products reinforced or otherwise combined with glass fibers and it 5 relates more particularly to the method and compositions employed in the treatment of the glass fibers to enhance the bonding relationship between the glass fibers and the elastomeric material for making fuller utilization of the desirable characteristics of the glass fi- 10 bers in their combination with the elastomeric materials.
The term "glass fibers," as used herein, shall refer to (1) continuous fibers formed by the rapid attenuation of hundreds of streams of molten glass and to strands 15 formed when such continuous glass fiber filaments are gathered together in forming; and to yarns and cords formed by plying and/or twisting a number of strands together, and to woven and non-woven fabrics which are formed of such glass fiber strands, yarns or cords, 20 and (2) discontinuous fibers formed by high pressure steam or air directed angularly downwardly onto multiple streams of molten glass issuing from the bottom side of a glass melting bushing and to yarns that are formed when such discontinuous fibers are allowed to rain 25 down gravitationally onto foraminous surface wherein the fibers are gathered to form a silver which is drafted into a yarn; and to woven and non-woven fabrics formed of such yarns of discontinuous fibers, and (3) combinations of such continuous and discontinuous fi- 30 bers in strand, yarn, cord and fabrics formed thereof.
As used herein, the term "elastomer" is meant to include natural rubber in the cured or uncured stage, vulcanized or unvulcanized stage, and synthetic organic 3-> elastomeric materials such as butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, chloroprene, isoprene, neoprene, isobutyl rubber and the like , elastomeric polymers and copolymers in their cured or uncured stages, and vulcanized or unvulcanized stages. 40 Included also are the EPDM rubbers, such as formed by the interpolymerization of ethylene, an alphamonoolefin having from 3-20 carbon atoms, such as propylene, and a polyene, such as dicyclopentadiene, 1,4-hexadiene and preferably an alkylene or alkylidene 45 norbornene, such as 5-alkylidene-2-norbornene and the like in which the alkylidene group numbers from 2-12 carbon atoms.
The invention is addressed to the fuller utilization of . the desirable characteristics of glass fibers, such as their high strength, flexibility, thermal stability, chemical stability, inertness, electrical resistance and heat conductive characteristics when used in combinations with elastomeric materials as a reinforcement or as a stabilizing agent in belt manufacture, as reinforcing cords and fabrics to increase strength, life, wearability and service characteristics in rubber tires, and as a reinforcement and the like in other elastomeric coated fabrics and a molded elastomeric products. 60
It is an object of this invention to provide a new and improved composition which may be used as a forming size for treatment of glass fibers in forming or preferably as an impregnating composition for treatment in forming or afterwards, of bundles, yarns, cords, strands 65 and fabrics formed of glass fibers to enable fuller utilization to be made of the desirable characteristics of the glass fibers when used in combination with elastomeric
materials in the manufacture of glass fiber reinforced molded products and coated fabrics.
More specifically, it is an object of this invention to provide a composition for use in the treatment of glass fibers in forming to improve the processing and the performance characteristics of the glass fibers as a reinforcement for elastomeric materials and for use in the treatment of bundles, strands, yarns, cords and fabrics of glass fibers, in forming or afterwards, to enhance their bonding relationship when used in combination with elastomeric materials in the manufacture of glass fiber reinforced plastics, laminates or coated fabrics and it is a related object to provide a method and means for making fuller utilization of the strength properties of glass fibers when used as a reinforcement for elastomeric materials.
These and other objects and advantages of this invention will hereinafter appear and, for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the accompanying drawing in which:
FIG. 1 is a flow diagram showing the manufacture of continuous glass fibers and the treatment thereof in forming to improve the processing characteristics of the glass fibers and to improve the performance characteristics of the glass fibers when used in combination with elastomeric materials in the manufacture of glass fiber reinforced elastomeric products;
FIG. 2 is a flow diagram illustrating the treatment of glass fibers subsequent to their being formed into bundles in accordance with the preferred practice of this invention;
FIG. 3 is a cross-sectional view of glass fibers processed in accordance with the diagram illustrated in FIG. 1; and,
FIG. 4 is a cross-sectional view of a bundle of glass fibers processed in accordance with the flow diagram of FIG. 2.
Until recently, glass fibers which have been added or otherwise incorporated with elastomeric materials, in the form of continuous or chopped fibers, have functioned more or less as a filler than as a reinforcement, or flexibilizing agent, or stabilizing agent. As a result, little, if any, improvements in mechanical and physical properties have been made available from the combinations which made use of glass fibers in products formed of elastomeric materials. It is believed that the past failure to make fuller utilization of some of the more desirable properties of the glass fiber components resides in the inability properly to integrate the glass fibers with the elastomeric system.
Investigations have been conducted over the past several years by the most highly skilled in the art in the attempt to make fuller utilization of the glass fiber components formulated into elastomeric materials in the endeavor to fabricate products having new and improved physical and mechanical properties. Substantial inroads are continuing to be made as represented by the practice of this invention, as will hereinafter be described.
The concepts of the present invention reside in new and improved coupling agents which can be used to enhance the bonding relationship of glass fibers with elastomeric material in the manufacture of glass fiber reinforced elastomeric products. In accordance with one embodiment of the invention, use is made of a resorcinolato silicon compound in which the silicon atom is
wherein n is an integer from 1 to 3, R is an organic group other than resorcinolato or hydrogen, R( is hydrogen or C, to C3 alkyl, m is an integer from 0 to 2, and preferably 0 to 1 and Z is a readily hydrolyzable group, such as halogen (chlorine, bromine, iodine and fluorine) or an alkoxy group containing 1 to 6 carbon atoms (e.g. methoxy, ethoxy, propoxy, etc).
As the R group, use is preferably made of compounds wherein R is alkyl containing 1 to 8 carbon atoms (e.g. methyl, ethyl, isopropyl, etc), alkenyl containing 2 to 6 carbon atoms (e.g. vinyl, allyl, etc) or aryl, such as phenyl, benzyl, etc. In addition the R groups described can be substituted with an amino group or an epoxy group.
The foregoing coupling agents can be prepared by a variety of methods, but the preferred method is described below. Initially, resorcinol is halogenated to form the mono-halogenated derivative in a conventional manner
The product of (IV) can be used directly as a coupling agent in accordance with the invention, but is preferably converted to the corresponding resorcinol by hydrolysis with aqueous HI.
As will be appreciated by those skilled in the art, the value of n will depend upon the ratio of resorcinol magnesium bromide to silicon tetrahalide. The products of (V) can be converted to the corresponding alkoxy silane derivatives by hydrolysis with an alkanol-alkali metal hydroxide mixture. Alternatively, use can be made of an alkoxy halo silane as illustrated by the following equation