Reinforcement fabric ply, compound and contiuous belt made thereof

Abstract: A reinforcing fabric (10) comprises reinforcing warp cords (12) and weft cords (14) that melt at a temperature of 93°C (200°F) to 149°C (300°F). The weft cords (14) hold the warp cords (12) in position relative to one another when the fabric is being calendered and placed in an elastomeric composite, but melt at the normal curing temperature of an elastomer (22) to form domains (17) of polymer in the cured composite. The reinforcing fabric (10) has particular use as reinforcement in V-belts.

Description: Background of the Invention 1. The invention relates to reinforcing fabric, its use in drive belts such as poly-V belts. 2. Fabric reinforcement is known to provide a stiffening effect in rubber products, especially when laminated fabric plies are used. When laminated fabric plies are used, the reinforcement cords in each ply are usually "laid-up" at different angles in the rubber product, which enhances this stiffening effect since the cords in each ply have different angles of primary stiffness and work against each other. 3. In some rubber products the reinforcement is provided to prevent stretching or growth of the product or to provide strength in drive applications. In a drive belt, for example, reinforcement in the drive direction of a belt may be provided by cords which provide the drive strength for the belt, and reinforcement perpendicular to the drive direction helps maintain the integrity of the belt in use, i.e. "perpendicular" reinforcement helps prevent separation of the drive cords. 4. In a drive belt, however, stiffness is not a desirable property since the belt must be easily bended around pulleys and/or sheaves which sometimes have relatively small diameters. Stiffness in such a use equates to resistance, and reduces the efficiency of any drive system using such a belt. 5. GB-A- 929,471 discloses a fabric reinforcement, wherein the fabric comprises a first plurality of parallel warp direction filaments selected from steel, and a second plurality of weft direction filaments having a melting temperature of 93°C to 149°C, said first and second filaments being interwoven, whereby two plies of this fabric may be superimposed, the warp filaments of one fabric ply extending at right angles to the warp filaments of the other ply. The superimposed plies are subjected to heat to melt the weft direction filaments of the plies to a certain extent and flow around the filaments. As the fabric is cooled, the weft filaments resolidify, whereby the two fabric plies are firmly bonded to one another. 6. It is an object of the invention to provide a reinforcement fabric that can be incorporated into an elastomeric product that provides strength in substantially one direction, and elastomeric products made using such a reinforcement fabric. Other objects of the invention will be apparent from the following description and claims. 7. The present invention provides a method of making a composite from an uncured elastomeric matrix and a continuous belt comprising an elastomeric matrix as defined in the claims 1,4 and 6 respectively. 8. The method of making the composite may comprise interweaving cords or filaments which loop over, under and around the first and second plurality of cords or filaments. 9. The method of making a woven fabric for the composite may comprise the steps of (a) disposing a first plurality of cords or filaments selected from the group comprising cotton, rayon, polyester, nylon, polyvinylalcohol, fiberglass, steel, aramid, carbon and mixtures thereof substantially parallel to one another, (b) disposing a second plurality of cords or filaments having a melting temperature of 93°C (200°F) to 149°C (300°F) substantially parallel to one another and substantially perpendicular to said first plurality of cords such that said second plurality of cords comprises 1/3 to 1/8 the number of cords in said first plurality of cords and contacts said first plurality of cords but are not interwoven therewith, and (c) looping an interweaving cord or filament over, under and around said first plurality and second plurality of cords or filaments. 10. In the illustrated embodiment the continuous belt is made using reinforcement fabric having non-interwoven reinforcement cords and weft cords which are held in position relative to one another by interweaving cords or filaments. Also the reinforcement cords are oriented perpendicular to the direction of movement of the belt and the belt has a per unit area flexibility substantially equal to the per unit area flexibility of a single reinforcement cord imbedded in the elastomeric matrix having a thickness substantially equal to the rivet of the belt. 11. Brief Description of the Drawing Fig. 1 illustrates a top view of a portion of the fabric of the invention. Fig. 2 illustrates an enlarged schematic view of an embodiment where the warp and weft are knitted. Fig. 3 illustrates a further enlarged side view taken on line 3-3 of the knit structure shown in Fig. 2. Fig. 4 illustrates an end view taken on line 4-4 of the knit structure shown in Fig. 2. Fig. 5 illustrates a green belt using the reinforcement of the invention, with the top layer rolled back to expose the reinforcement. Fig. 6 illustrates a cured poly-V belt structure using the same reinforcement. 12. Detailed Description of the Invention With reference now to Fig. 1, fabric reinforcement 10 of the invention comprises reinforcing warp yarns or cords 12, and non-reinforcing weft yarns or cords 14 perpendicular thereto. As is known in the art, the end count of the warp cords (ends per centimeter) or (epcm) [(ends per inch) or (epi)] is much higher than the end count of the weft cords, because the weft cords are typically used mainly to hold the warp cords in position relative to one another. Typically warp cords have an end count of 3,9 to 7 epcm (10 to 18 epi), and weft cords have an end count of 0,2 to 1,6 epcm (0.5 to 4 epi). The warp and weft cords may be woven together to maintain their relative position, or as illustrated in structure 10a of Figs. 2-4, the warp and weft cords can be knitted to each other and held in place by knit filaments 16. 13. In the fabric of the invention, warp cords 12 comprise a tough, strong, high melting material such as cotton, rayon, polyester, nylon, polyvinylalcohol, fiberglass, steel, aramid, carbon and mixtures thereof. The weft cords 14 comprise a polymeric material that melts in the range of 93°C (200°F) to 149°C (300°F) such as polypropylene, polyethylene and mixtures thereof. The melting temperature of the weft cords is typically in the curing temperature range of an elastomeric product, and when incorporated in an elastomeric product, the weft cords melt away, forming domains 17 of polymeric material in the elastomeric product. The interweaving knit filaments 16 may either comprise a material which melts away as e.g. used for weft cords 14 or can be of a textile material having a higher elongation than the warp cords 12. 14. With reference now to Figs. 5 and 6, the use of the reinforcement of the invention is illustrated in a poly-V belt 20 and green continuous belt 20a. Those skilled in the art will recognize that such reinforcement can be used in V-belts, and other types of continuous belts. 15. In the illustrated embodiment, Poly V® belt 20 is comprised of six ribs 24 for use with a six groove sheave. Cords 18 provide the drive strength for the belt and may comprise aramid, steel, polyester, glass or similar high tensile strength material. When such a Poly-V® belt is used, cords 18 are stressed at high speeds and the forces encountered in driving or being driven by sheaves tend to separate cords 18 from one another. In the structure of such belts, high strength filaments or cords 12 are applied over drive cords 18, and perpendicular thereto to work against the tendency of the cords to separate, and to help prevent the splitting of the belt. 16. Since it is not efficient to apply cords 12 individually, perpendicular to the direction of movement of the belt, such cords are usually applied in a fabric as shown in Fig. 1 or Fig. 2. The weft cords 14 of such a fabric, which are necessary to hold cords 12 in place while the fabric is calendered or otherwise coated with rubber, add to the stiffness of the construction since they restrict the independent movement of warp cords 12, and add to the thickness and stiffness of the reinforcement package. 17. In the concept of the instant invention, it was theorized that removal of weft cords 14 would increase the flexibility of a product made using such reinforcement by releasing the stress on warp cords 12 and permitting them to move independently of one another. Since warp cords 12 are perpendicular to the direction of movement of Poly-V® belt 20 and an are free to move independently, the unit area stiffness added to the belt 20 by this ply would be substantially equal to the stiffness of a single reinforcement cord 18 embedded in the thickness of rubber equivalent to the rivet of the ply. 18. To practice the invention, it was proposed to make weft cords 14 of a polymeric material that melts at the temperatures used to cure an elastomeric product in which it is used. Accordingly, if an elastomeric product is cured at a temperature of 93°C to 149°C (200°F to 300°F), and the weft cords melt at such a temperature, the weft cords melt and form domains 17 of polymeric material in the elastomer 22 when the elastomer is cured. Fabric having the construction described above was prepared for such purpose according to Goodyear specifications by Wellington-Sears. 19. While the invention has been specifically illustrated and described, those skilled in the art will recognize that the invention can be variously modified and practiced. The invention is limited only by the following claims.

Claims: A method of making a composite from an uncured elastomeric matrix and a fabric reinforcement, said fabric reinforcement comprising a first plurality of substantially parallel warp direction cords or filaments (12) selected from the group comprising cotton, rayon, polyester, nylon, polyvinylalcohol, fiberglass, steel, aramid, carbon and mixtures thereof, and a second plurality of weft direction cords or filaments (14) having a melting temperature of 93°C (200°F) to 149°C (300°F), said first and second plurality of cords and filaments being in contact with one another but not being interwoven, said first and second plurality of cords or filaments being held in position relative to one another by interweaving cords or filaments (16) whereby the composite is cured at a temperature where the weft cords melt and form domains (17) of polymeric material in the elastomeric matrix. The method of claim 1 characterized in that said weft cords (14) comprise polypropylene, polyethylene or mixtures thereof. The method of claim 1 characterized in that the interweaving cords or filaments (16) comprise a material which melts away as used for the weft direction cords or filaments. A method of making a composite from an uncured elastomeric matrix and a fabric reinforcement, wherein said fabric reinforcement comprises a first plurality of substantially parallel warp direction cords or filaments (12) selected from the group comprising cotton, rayon, polyester, nylon, polyvinylalcohol, fiberglass, steel, aramid, carbon and mixtures thereof, and a second plurality of weft direction cords or filaments (14) having a melting temperature of 93°C (200°F) to 149°C (300°F), said first and second plurality of cords and filaments being interwoven whereby the composite is cured at a temperature where the weft cords melt and form domains (17) of polymeric material in the elastomeric matrix. The method of claim 4 characterized in that said weft cords (14) comprise polypropylene, polyethylene or mixtures thereof. A continuous belt (20) comprising an elastomeric matrix (22) reinforced by a plurality of parallel reinforcement warp cords or filaments (12) characterized in that said reinforcement cords or filaments are not connected to each other and move independently of one another in said elastomeric matrix and in that the elastomeric matrix contains domains (17) of polymeric material originating from weft cords (14) of polymeric material having a melting temperature of 93°C (200°F) to 149°C (300°F) and molten at the temperature used to cure the belt. The continuous belt (20) of claim 6 characterized in that said belt is made using reinforcement fabric having non-interwoven reinforcement cords (12) and weft cords (14) which are held in position relative to one another by interweaving cords or filaments (16) and where said weft cords (14) comprise a polymeric material having a melting temperature of 93°C (200°F) to 149°C (300°F) and said weft cords or filaments are melted and dispersed in said elastomeric matrix during the curing of said belt, creating said polymer domains (17) in said elastomeric matrix. The continuous belt (20) of claim 6 characterized in that said reinforcement cords (12) are oriented perpendicular to the direction of movement of said belt and said belt has a per unit area flexibility substantially equal to the per unit area flexibility of a single reinforcement cord imbedded in said elastomeric matrix. The continuous belt (20) of claim 6 characterized in that said belt is made using reinforcement fabric having interwoven reinforcement cords (12) and weft cords (14) and said weft cords comprise a polymeric material having a melting temperature of 93°C (200°F) to 149°C (300°F) and said weft cords or filaments are melted and dispersed in said elastomeric matrix (22) during the curing of said belt, creating said polymer domains (17) in said elastomeric matrix.

Inventors: GOETTSCH LARRY DEAN, OTRADOVEC STEPHEN CHARLES, GOETTSCH, LARRY DEAN, OTRADOVEC, STEPHEN CHARLES
Applicants: GOODYEAR TIRE & RUBBER, THE GOODYEAR TIRE & RUBBER COMPANY
Application year: 1996
Main classification: B60C9
IPC codes: B60C9, B32B5, D03D1, D03D15, D03D25, F16G5, F16G1, D04B21, B32B25