KR20140030321A - Reinforced rubber article with tape elements - Google Patents

Abstract

Reinforced rubber articles are disclosed that contain a rubber article and a layer of fibers embedded in the rubber article. The fiber layer contains a uniaxially drawn tape element of a rectangular cross section having a first layer having a draw ratio of at least about 5 or more, a modulus of at least about 2 GPa and a density of at least 0.85 g / cm ³ . The first layer contains a polymer selected from the group consisting of polyamides, polyesters and copolymers thereof. Also disclosed are methods of making reinforced rubber articles.

Description

Reinforced rubber articles with tape elements {REINFORCED RUBBER ARTICLE WITH TAPE ELEMENTS}

The present invention relates generally to fiber reinforced rubber articles.

Reinforced rubber products are used in a wide variety of consumer and industrial applications. The performance of the reinforced molded rubber article depends on the adhesion of the reinforcement to the rubber. Fabrics made from synthetic yarns tend to be difficult to bond to rubber.

Indeed, several are being done to improve adhesion, many of which involve coating the fibers and / or fabrics with adhesion promoters. For example, a spin finish may be applied which may contain an adhesion activator such as an epoxy resin when the fiber is drawn.

There is still a need for reinforced rubber articles with improved adhesion due to fiber geometry and other physical properties in addition to adhesion promoting agents.

The reinforced rubber product contains a rubber product and a layer of fibers embedded in the rubber product. The fiber layer contains a uniaxially drawn tape element having a rectangular cross section and a first layer having a draw ratio of at least about 5 or more, a modulus of at least about 2 GPa, a density of at least 0.85 g / cm ³ . The first layer contains a polymer selected from the group consisting of polyamides, polyesters, and copolymers thereof. Also disclosed are methods of making reinforced rubber articles.

1 schematically shows a fibrous layer that is a fabric embedded in rubber.
2 is a cutaway view of a pneumatic radial tire;
3 and 4 show a reinforced rubber article that is a hose.
5 schematically illustrates one embodiment of an air spring containing a tape element.
6 schematically depicts an embodiment of an exemplary tape element having one layer.
7 schematically depicts an embodiment of an exemplary tape element having two layers.
8 schematically depicts an embodiment of an exemplary tape element having three layers.
9 schematically depicts an embodiment of an exemplary tape element having voids and surface crevices.
10 is a micrograph at 50,000 times magnification of a cross section of one embodiment of a fiber containing voids.
FIG. 11A is a micrograph at 20,000-fold magnification of a cross section of one embodiment of a fiber containing voids and void-initiating particles showing some diameter measurements of the voids. FIG.
FIG. 11B is a micrograph at 20,000 times magnification of a cross section of one embodiment of a fiber containing voids and pore-inducing particles, showing several length measurements of the voids. FIG.
12 is a micrograph at 1,000 times magnification of the surface of one embodiment of a fibrous fiber.
13 is a micrograph at 20,000 times magnification of the surface of one embodiment of a fibrous fiber.
14 is a micrograph at 100,000 times magnification of the surface of one embodiment of a fibrous fiber.
15 schematically illustrates one embodiment of a fabric made from a tape element.

1 shows a reinforced rubber product 200 containing a fiber layer 100 embedded in rubber 220. The fiber layer 100 contains a plurality of fibers 10. The reinforced rubber product 200 may be any rubber product reinforced with fibers, such as tires, belts, air springs, hoses, and the like.

Referring now to FIG. 2, one embodiment of a reinforced rubber product 200 is shown that is a tire that includes a sidewall 303 connected to a tread 305 by a shoulder. The tire 200 includes a carcass 301 covered by the tread 305. In FIG. 2, the tire 200 is a radial tire. However, the present invention is not limited to radial tires, and may be used for other tire structures. The carcass 301 terminates around the inside of the tire in the metal bead 307, with one or more belt plies 334 located around the circumference of the tire cord 312 in the tread 305 region. Made of one or more plies of cords 312. The carcass 301 is configured such that the reinforcement cord 311 runs substantially radially in the intended direction of rotation R of the tire 200. The belt ply 334 is made of a relatively inextensible warp material 331, such as a steel core reinforcing warp, which extends in the intended direction of rotation (R) of the tyre, or more typically at some angle thereto. The angle of the inextensible warp material 331 may vary depending on the configuration or application method. A breaker 330 extends across the width of the tread 305 of the tire and terminates at the edge 332 of the tire zone 220 where the tread 305 meets the sidewall 303.

A cap ply layer 343 is positioned between the belt ply 334 and the tread 305. The illustrated cap ply layer 343 is made of cap ply tape 342 that wraps around the tire cord 312 in the direction in which the tire rolls and extends over the edge 332 of the belt ply 334. In addition, the cap lap tape 342 of FIG. 2 can be wound around the tire cord 312 a plurality of times to reduce the imbalance effect on the tire 200 caused by overlap overlap. Alternatively, the cap ply layer 343 can be formed from the cap ply tape 342 extending over the edge 322 of the belt ply 334 or the circumference of the carcass 301 of the tire 200 in a flat spiral pattern. Cap ply layer 343 can be made from cap ply tape 342 wound around. Some suitable cap ply fabrics are described in US Pat. Nos. 7,252,129, 7,614,436, and 7,931,062, each of which is incorporated herein by reference.

Above the bead 307 is a bead apex 310, and at least partially surrounding the bead 307 and the apex 310 is a flipper 320. The flipper 320 is a fabric layer disposed around the beads 307 and inside the portion of the turn-up end 330. A chipper 340 is disposed adjacent to the portion of the ply 330 wound around the bead 307. More specifically, the chipper 340 is disposed opposite the "turn-up end" 330 fold from the flipper 320. The sidewall may also be a layer of another fabric not shown, for example a chafer fabric, toe, extending from the bead to the side of the sidewall, extending from the tread down the sidewall, in a shoulder region, or completely covering the sidewall. It may also contain a protective fabric or a fabric surrounding the bead. Any fabric extending between the bead and the tread is defined herein as "sidewall fabric". This includes fabrics, such as flipper fabrics, that also extend into the interior of the tire around the beads, as long as at least a portion of the fabric is located between the beads and the tread.

The tire carcass is required to have considerable strength in the radial direction from bead to bead across the direction of rotation during use. To provide this strength, the fabric stabilizing material (also known as tire cord) is typically pre-drawn in the warp direction (also known as the "machine direction") drawn and tensioned during the fabric manufacturing process and / or finishing process. It had a fabric with substantially inextensible high toughness yarns under pressure. This fabric is then cut in the transverse machine direction (ie across the warp yarns). The individual fabric pieces are then rotated 90 ° and assembled together to position the carcass so that the high strength warp yarns are oriented in the desired radial direction between the beads. Therefore, in the final structure, the weft yarns are oriented substantially in the circumferential direction (ie in the direction of rotation).

In another embodiment, the carcass stabilizing fabric is made of warp knitted weft insert fabric with weft insert yarns made from relatively inextensible reinforcement cords. Alternatively, the carcass stabilizing fabric may be a fabric having weft yarns made of relatively inextensible reinforcement cords or laid scrims. More information on this stabilizing fabric with a relatively unstretched reinforcement cord in the weft direction of the fabric can be found in US Patent Application No. 12 / 836,256, filed July 14, 2010, incorporated herein by reference. .

The fiber layer 100 of the tire (reinforced rubber product 200) of FIG. 2 includes a cap ply, a carcass ply, a chafer, a flipper, a clipper, a body ply, a shoulder ply, a belt ply, a belt separator ply, a bead wrap, Belt edge wrap, or any other fibrous layer in the tire.

Referring now to FIGS. 3 and 4, a reinforced rubber product 200 in the form of a fabric reinforced hose is shown. One of the most widespread and most suitable conventional hoses is the so-called "mesh-reinforced" type, where the fiber layer 100 is formed by yarns spirally wound on a flexible hose, forming two sets of yarns. A first set of fabric “meshes” having diamond-like cells superimposed on the same number of transverse threads along parallel equidistant lines arranged in parallel equidistant rows and symmetrically arranged about the axis of the tubular body of the hose. To form. Any other suitable fibrous layer 100 can also be used in the hose. The fibrous layer 100 is embedded into the rubber 220. In addition to the hose, the fiber and fiber layers can be used to reinforce any other suitable rubber product, including belts such as power transmission belts, printer blankets, and tubes.

Some other reinforced rubber products 200 include a print blanket and a power transmission belt. In offset lithography, a common function of a printing blanket is to transfer printing ink from a printing plate to a product such as printed paper so that the printing blanket repeatedly contacts the associated printing plate and the printed paper. Printer blankets typically include fabrics embedded in rubber. Power transmission belts and other types of belts also contain rubber reinforced with fibers.

Pneumatic springs, commonly referred to as air springs, provide many years of application to absorb shock loads on axles by wheels that bump objects or fall into recesses to provide cushioning between movable parts of the vehicle. Has been used. These air springs typically include compressed air or other fluid sources and have a flexible elastomeric sleeve or bellows having one or more pistons positioned within the flexible sleeve to cause compression and expansion when the vehicle is subjected to road shocks. It consists of The piston causes compression and expansion in the spring sleeve, and the sleeve is a flexible material that allows the piston to move axially with respect to each other inside the sleeve. The ends of the sleeve are typically sealingly connected to the piston or end member, and at least one allowing the end members to move axially with respect to each other between the oscillating or collapsed position and the recoil or extended position without damaging the flexible sleeve. Has a dried end

It is desirable to use a braking machine or device in conjunction with such air springs to provide braking for controlling the movement of the air springs. In one embodiment, a rubber reinforced product is used for the air spring. In some embodiments, rubber reinforced articles are used as spacers for pistons or as bead plates of air spring assemblies.

5 schematically illustrates a reinforced rubber product 200 that is a sleeve in one type of air spring 400. Fiber 10, preferably tape element 10, is embedded in rubber to form sleeve 200, which serves to reduce vibrations of cars and other machinery. In FIG. 5, the sleeve 200 has two ends, an upper end 405 connected to the end cap 401 and a lower end 406 connected to the piston 402. While one variation of the air spring 400 is shown, the reinforced rubber product 200 can be used in any air spring structure. The cross section of the fiber, tape element 10, can be seen in the cutaway view of the air spring 400 when the tape element 10 is oriented circumferentially within the sleeve 403. This circumferential direction of the tape element imparts stiffness to the structure.

Fiber layer 100 is formed from fiber 10. The fiber 10 can be any fiber suitable for the end use. As used herein, "fiber" is defined as an elongated object. The fibers can have any suitable cross section, such as round, multi-lobed, square or rectangular (tape) and ovoid. In one embodiment, the fiber is a tape element 10. The tape element may have a rectangular or square cross section. These tape elements may also often be referred to as ribbons, strips, tapes, tape fibers, and the like.

One embodiment of a fiber that is a tape element is shown in FIG. 6. In this embodiment, the tape element 10 contains a first layer 12 having an upper surface 12a and a lower surface 12b. In one embodiment, the tape element 10 has a rectangular cross section. The tape element is considered to have a rectangular or square cross section even if one or more of the corners of the rectangle / square are slightly rounded or the opposite sides are not perfectly parallel. Having a rectangular cross section is desirable for some applications for a variety of reasons. First, the surface available for bonding is larger. Second, during the de-bonding process, the entire width of the tape is under tension and the shear point is significantly reduced or eliminated. In contrast, multifilament yarns have very few zones under tension, with areas of varying ratios of tension and shear along the circumference of the fiber. In other embodiments, the cross section of the tape element 10 is square or approximately square. Having a square cross section may also be desirable in some cases where the width and size are so large that stacking more tapes at a given width increases the load carrying capacity of the entire reinforcing element.

In one embodiment, the tape element has a width of about 0.1 to 6 mm, more preferably about 0.2 to 4 mm, more preferably about 0.3 to 2 mm. In other embodiments, the tape element has a thickness of about 0.02 to 1 mm, more preferably about 0.03 to 0.5 mm, more preferably about 0.04 to 0.3 mm. In one embodiment, the tape element has a width of about 1 mm and a thickness of about 0.07 mm.

The first layer 12 of the fiber 10 can be any suitable orientable (meaning the fibers can be oriented) thermoplastic. Some thermoplastics suitable for the first layer include polyamides, co-polyamides, polyesters, co-polyesters, polycarbonates, polyimides and other oriented thermoplastic polymers. In one embodiment, the first layer contains polyamide, polyester and / or copolymers thereof. In one embodiment, the first layer contains polyamide or polyamide copolymer. Polyamides are preferred for some applications because they have high strength, high modulus, high temperature retention properties and fatigue performance. In other embodiments, the first layer contains a polyester or polyester copolymer. Polyester is preferred for some applications because of its high modulus, low shrinkage and excellent temperature performance.

In one embodiment, the first layer 12 of the tape element 10 is a blend of polyester and nylon 6. The polyester is preferably polyethylene terephthalate. Polyester is used because of its high modulus and high glass transition temperature, which has led to the use of polyester in tire cords and rubber reinforcement cords primarily due to its flat-spotting resistance. Nylon 6 is used for several reasons. This is easier to process than nylon 6 6. One of the main reasons for incorporating nylon 6 in these embodiments is to act as an adhesion promoter. Nylon 6 has surface groups on which resorcinol formaldehyde latex forms major chemical bonds through the resol group. This blend is a physical blend, not a copolymer, and the polyester and nylon 6 are immiscible with each other. In one embodiment, the powder or felt of polyester and nylon 6 is simply mixed in the unmelted state to form a blend that is fed to the extruder. Tape elements extruded from this physical blend provide good adhesion to rubber and high modulus.

In addition, nylon 6 polymerization results in the miscibility of polyester and nylon 6 by producing a certain amount of unreacted monomer lactam that acts as a comonomer. The methylene-ester interaction allows the binary blend to tolerate large differences in methylene content before phase separation occurs. In blends with large differences in methylene groups (as in this case), entropy may occur when the fragment interaction parameters of the blend are less than the threshold. Although some phase separation and crystallization of phase separation elements can be avoided, the majority of tape elements appear to be homogeneously mixed. Nylon 6 6 is undesirable for use due to large phase separation at relatively low volume fractions of nylon 6 6 in polyester. This may be due to several reasons. Nylon 6 6 has a higher degree of polymerization than nylon 6. Second, the crystallization rate of nylon 6 6 is much greater than that of nylon 6. This is due to the fact that nylon 6 6 with symmetrical arrangements can be incorporated into the crystal lattice much more easily than nylon 6 chains, which must be packed in antiparallel chains for complete hydrogen bonding.

There is also a unique reason that the particular process employed is advantageous for extruding and drawing the blended polymer. As mentioned above, some amount of phase separation can be avoided. If the extrudate is too small, as in the case of single filament and multiple filament spinneret holes, the element may not be drawn and may not be extruded. This is not a problem for this particular process because the process is similar to the film drawing process, which can tolerate a small degree of phase separation and crystallization of these phases without creating a completely separated area due to the wide slot die opening. to be.

In one embodiment, the blend of polyester and nylon 6 contains about 50 to 99 weight percent polyester and about 50 to 1 weight percent nylon 6. More preferably, the blend of polyester and nylon 6 contains about 60 to 95 weight percent polyester and about 40 to 5 weight percent nylon 6. Most preferably, the blend of polyester and nylon 6 contains about 70 to 90 weight percent polyester and about 30 to 10 weight percent nylon 6. Weight ratios outside of the prescribed ranges result in excessive phase separation and crystallization in the extrudate quench tank causing the urea to separate from the main extrudate. Weight ratios beyond these areas require special compatibilizers such as excess lactam monomer and co-polyester.

In one embodiment, the tape element preferably has a draw ratio of at least about 5, a modulus of at least about 2 GPa and a density of at least about 1.2 g / cm ³ . In other embodiments, the first layer has a draw ratio of about 6 or greater. In other embodiments, the first layer has a modulus of at least about 3 GPa or at least about 4 GPa. In other embodiments, the first layer has a density of at least about 1.3 g / cm ³ and a modulus of about 9 GPa. The first layer with high modulus is desirable for better performance in applications such as tire cords, cap plies, overlays or carcass plies for tires. Lower densities of these fibers are desirable to obtain lower weights. Fibers with voids generally tend to have lower densities than fibers without voids.

In one embodiment, the fiber contains a second layer as shown in FIG. 7. 7 shows a fiber 10 having a first layer having an upper surface 12a and a lower surface 12b and a second layer 14 on the upper surface 12a of the first layer 12. On the lower surface 12b of the first layer 12 there may be an additional third layer 16 as shown in FIG. 8. While the second layer 14 and the third layer 16 are shown on the fiber 10 which is a tape element of rectangular cross section, the second layer and / or the third layer may be on any shape of fiber. . When the second layer 14 and the third layer 16 are applied to a fiber having no flat side, the upper half of the circumference is referred to as the "top" surface and the lower half of the circumference is referred to as the "lower" surface.

The optional second layer 14 and third layer 16 may be formed simultaneously with the first layer in a process such as coextrusion or may be applied after the first layer 12 is formed in a process such as coating. The second and third layers preferably contain the same class of polymers as the polymers of the first layer, but may also contain additional polymers. In one embodiment, the second and / or third layer contains a block isocyanate polymer. The second layer 14 and the third layer 16 can help the adhesion of the fibers to the rubber. Preferably, the melting point T _m of the first layer 12 is higher than the T _m of the second layer 14 and the third layer 16.

In one embodiment, the fiber 10 (preferably, tape element 10) contains a plurality of voids. 9 shows a fiber 10 having a first layer 12 containing a plurality of voids 20. 10 is a micrograph at 50,000 times magnification of a cross section of one embodiment of a fiber containing voids. "Pore" is used herein to mean that there are no solid and liquid materials added, but "pore" may contain a gas. It is commonly accepted that fibers with voids may not have the physical properties required for use as reinforcements in rubber articles, but fibers with voids have been found to have some unique advantages. First, the presence of voids in the fibers requires the sacrifice of polymeric material. This means that the density of these fibers is lower than the fibers without voids. The volume fraction of the voids determines the percentage by which the fiber has a lower density than the polymer resin. Secondly, the voids act as a bladder for the adhesion promoter to be injected into the fibers with voids / layers with voids to provide a fixation effect. Third, the shape of these voids can suppress the crack propagation tip in the case of fatigue. The extra surface available for crack propagation reduces the loss of stress specificity in the case of periodic fatigue, including tensile and / or compressive loading. In the case of the thermoplastic polymer constituting the first layer 12 of the fiber 10, high shear flows up to chain orientation and elongation during excessive drawing of the layer to form regions or voids lacking the presence of the polymer. The voids may be present in any layer or all layers 12, 14, 16 of the fiber 10. In addition, the fibrous layer 100 may contain some fibers with no voids and some fibers with voids.

The void 20 typically has a needle-like shape, meaning that the diameter of the cross section of the void perpendicular to the fiber length is much smaller than the length of the void due to the uniaxial orientation of the fiber. This shape is due to the uniaxial drawing characteristic of the fiber 10.

In one embodiment, the voids are present in the fiber in an amount of about 3-20% by volume. In other embodiments, the voids are present in the fiber in an amount of about 3-18% by volume, about 3-15% by volume, 5-18% by volume, or about 5-10% by volume. Density is inversely proportional to the pore volume. For example, if the pore volume is 10%, the density is reduced by 10%. Since an increase in voids is typically observed at higher draw ratios, which results in higher strength, a decrease in density results in an increase in the specific strength and modulus of the fiber, which is desirable for some applications such as high performance tire reinforcement.

In one embodiment, the size of the pores formed has a diameter of about 50 to 400 nm, more preferably 100 to 200 nm, and a length of about 1 to 6 microns, more preferably about 2 to 3 microns.

The pores 20 of the fiber 10 may be formed during a uniaxial orientation process without additional material, meaning that the pores do not contain any pore-inducing particles. The orientation of the fiber bundles is a driving factor of the origin of the voids in the fiber. Sliding between semi-molten materials is believed to result in void formation. The water density of the pores depends on the viscoelasticity of the polymer element. The uniformity of the pores along the transverse width of the oriented fiber depends on whether the complete polymer element is oriented in the drawing process along the machine direction. In order for the complete polymer element to be oriented in the drawing process, it has been found that heat must be effectively transferred from the heating element (which can be water, air, infrared, electricity, etc.) to the polymer fibers. Typically, in industrial processes using hot air convection heating, one possible way to orient the polymer fibers and still maintain industrial speed is to limit the polymer fibers in terms of their width and thickness. This means that when the polymer fiber is extruded through a slot die or when the polymer is extruded through a film die and slitting to a narrow width prior to orientation, complete orientation along the machine direction can be more easily achieved.

In another embodiment, the fiber 10 contains pore-inducing particles. The pore-inducing particles can be any suitable particle. The pore-inducing particles remain in the finished fiber and the physical properties of the particles are selected in accordance with the desired physical properties of the resulting fiber. If pore-inducing particles are present in the first layer 12, the stress (e.g., uniaxial orientation) to the layer increases or elongates this defect caused by the particles, thereby causing voids around this defect in the orientation direction. Tends to stretch. The size and ultimate physical properties of the pores depend on the degree and balance of orientation, stretching temperature and rate, crystallization kinetics and particle size distribution. The particles can be inorganic or organic and can have any shape, such as spherical, platelet or irregular. In one embodiment, the pore-inducing particles are present in an amount of about 2-15% by weight of the fiber. In other embodiments, the pore-inducing particles are present in an amount of about 5-10% by weight of the fiber. In other embodiments, the pore-inducing particles are present in an amount of about 5-10% by weight of the first layer.

In one preferred embodiment, the pore-inducing particles are nanoclays. In one embodiment, the nanoclay has a closet in which 10% of the clay has a lateral dimension of less than 2 μm, 50% has a lateral dimension of less than 6 μm and 90% has a lateral dimension of less than 13 μm ( cloisite). The nanoclay has a density of about 1.98 g / cm ³ . Nanoclays may be desirable in some applications for a variety of reasons. First, nanoclays have good miscibility with various polymers, especially polyamides. Second, the high aspect ratio of the nanoclays is estimated to improve some mechanical properties due to preferential orientation in the machine direction. In one embodiment, the nanoclay is present in an amount of about 5-10% by weight of the fiber. In other embodiments, the nanoclay is present in an amount of about 5-10% by weight of the first layer. FIG. 11A is a micrograph at 20,000 times magnification of a cross section of an embodiment containing voids and pore-inducing particles, showing several diameter measurements of the voids, and FIG. 11B shows voids and voids, showing several length measurements of the voids. Micrograph at 20,000 times magnification of cross section of one embodiment containing trigger particles.

The second layer 14 and the third layer 16 of the fiber 10 may have voids or may be substantially free of voids. Having an outer shell layer (second layer 14 and third layer 16) having no voids reduces the peripheral effect of the extrusion process on the inner first layer 12, since the outer layer reduces the peripheral effect. (12) can help control the size and concentration of pores throughout. In one embodiment, second layer 14 and / or third layer 16 contain void-induced particles, voids and surface cracks, whereas first layer 12 contains voids but void-induced particles It does not contain.

Referring again to FIG. 6, in another embodiment, the fiber 10 contains cracks 40 on at least one outermost surface (top surface 10a or bottom surface 10b) of the fiber 10. . If the fiber 10 contains only the first layer, the top surface 10a of the fiber 10 corresponds to the top surface 12a of the first layer 12, and the bottom surface 10b of the fiber layer 10 is formed of the first layer 12. Corresponds to the lower surface 12b of the first layer 12. Cracks may also be present in the second layer 14 and / or third layer 16 which, when present, form the outermost surface of the fiber 10. 12 is a micrograph at 1,000 times magnification of the surface of one embodiment of a fibrous fiber. 13 is a micrograph at 20,000 times magnification of the surface of one embodiment of a fibrous fiber.

Cracks, also known as valleys, channels or grooves, are oriented along the length of the fiber 10 in a uniaxial orientation. The average size of these cracks is approximately 300-1000 μm in length and is present at a frequency of about 5-9 cracks / mm ² , as shown in FIG. 14 taken at 100,000 × magnification. Cracks are formed when defects are present on the surface of the fiber during the drawing or orientation process. In some embodiments, nanoclay particles or aggregated nanoclay particles may act as induced bonds. If nanoclay particles are present in the polymer element, the polymer element is oriented around the induced crack tip and propagates along this tip in the machine orientation direction to form cracks.

In one embodiment, the crack is formed by the pore-inducing particles. Preferably, the crack is formed from nanoclay pore-inducing particles. Surface defects, such as cracks, are typically seen as defects and minimized or eliminated in the fibers, but when the fibers in the fiber layer are coated with an adhesion promoter, the fibers 10 with cracks 40 are superior to the rubber when embedded in the rubber. It was found to exhibit adhesion. While not wishing to be bound by any particular theory, it is believed that the adhesion promoter at least partially impregnates and fills the cracks to form anchorages and improve the adhesion between the fibers and the rubber. In fact, when tested, the bond between the rubber and the rubber itself is broken before the bond between the fiber and the rubber is broken.

Referring again to FIG. 1, the fibrous layer 100 containing the fibers 10 may be any suitable fibrous layer, such as knitted, woven, nonwoven, and unidirectional fabrics. Preferably, the fibrous layer 100 has a structure that is sufficiently open to allow subsequent coating (eg, rubber) to pass through the fibrous layer 100 to minimize the formation of glazing.

In one embodiment, the fibrous layer is a fabric, such as plain weave, satin weave, twill weave, basket-knitting, poplin weave, jacquard and crepe weave fabrics. Preferably, the fabric is a plain weave fabric. Plain weave has been found to have good wear and wear characteristics. Twill zirconia has been found to have excellent properties in composite curves and may therefore be desirable for rubber products.

In other embodiments, the fibrous layer may be knitted, for example circular knit, reverse plate circular knit, dual knit, single jersey knit, two-end fleece knit, three-end fleece knit, terry knit or double loop knit It is a warp knit, with or without weft insert warp knit, warp knit and microdenier surface.

In other embodiments, the fibrous layer 100 is a multiaxial fabric (knitting, woven or nonwoven), such as triaxial. In other embodiments, the fibrous layer 100 is a bias fabric. In other embodiments, the fibrous layer 100 is a nonwoven. The term nonwoven refers to a structure that incorporates entangled and / or heat fused yarn masses to provide an integrated structure with some degree of internal bonding. Nonwovens for use as the fibrous layer 100 can be made from a number of processes such as, for example, melt spinning processes, hydroentangling processes, mechanical entanglement processes, stitch-bonding, and the like.

In other embodiments, the fibrous layer 100 is unidirectional and may have overlapping fibers or may have gaps between the fibers. In one embodiment, the fibers are wound continuously around the rubber article to form a unidirectional fiber layer. In some embodiments, spacing between the fibers can be induced to cause a slight leakage of rubber between the fibers, which can be advantageous for adhesion.

In one example, the fibrous layer 100 of FIG. 1 is a fabric embedded in rubber such that all of the depicted ends are fibers 10 (shown in FIG. 15 as a tape element 10 having a square cross section).

In other embodiments, the fibrous layer 100 contains yarns having different compositions, sizes, and / or shapes for the fibers and / or the fibers 10. These additional fibers include polyamide, aramid (including meta and para forms), rayon, PVA (polyvinyl alcohol), polyester, polyolefin, polyvinyl, nylon (including nylon 6, nylon 6,6, and nylon 4,6). , Polyethylene naphthalate (PEN), cotton, steel, carbon, glass fiber, steel, polyacryl, polytrimethylene terephthalate (PTT), polycyclohexane dimethylene terephthalate (PCT), polybutylene terephthalate (PBT) ), PET modified with polyethylene glycol (PEG), polylactic acid (PLA), polytrimethylene terephthalate, nylon (including nylon 6 and nylon 6,6); Regenerated cellulose (eg rayon or tencel); Elastomeric materials such as spandex; High performance fibers such as polyaramid; And polyimide natural fibers such as cotton, linen, ramie and hemp; Protein substances such as silk, hair and angora, alpaca and other animal hair such as Vicuna; Fiber reinforced polymers, thermoset polymers, blends thereof and mixtures thereof, but is not limited to these. These additional fibers / yarns can be used, for example, in the warp direction of the woven fiber layer 100 and the fiber 10 is used in the weft direction.

In one embodiment, the fiber is at least partially surrounded by an adhesion promoter. A common problem in producing rubber composites is maintaining good adhesion between rubber and the fiber and fiber layers. A common way to promote adhesion between rubber and fibers is to pretreat the yarn with an adhesive layer typically produced from a mixture of rubber latex and phenol-formaldehyde condensation products, where phenol is almost always resorcinol. This is the so-called "RFL" (resorcinol-formaldehyde-latex) method. Resorcinol-formaldehyde latex may contain vinyl pyridine latex, styrene butadiene latex, waxes, fillers and / or other additives. As used herein, "adhesive layer" includes RFL chemicals and other non-RFL rubber adhesive chemicals.

In one embodiment, the adhesive agent is not an RFL drug. In one embodiment, the adhesive agent does not contain formaldehyde. In one embodiment, the adhesive composition comprises an uncrosslinked resorcinol-formaldehyde and / or resorcinol-furfural condensate (or phenol-formaldehyde condensate that is soluble in water), rubber latex and 2-fururealdehyde Same aldehyde components. The composition can be applied to a textile substrate and used to improve the adhesion between the treated textile substrate and the rubber material. More information about these drugs can be found in US patent application Ser. No. 13 / 029,293, filed Feb. 17, 2011, which is incorporated herein by reference.

The adhesive layer may be applied to the fibers prior to forming into the fiber layer or after forming the fiber layer in any conventional manner. Preferably, the adhesive layer is a resorcinol formaldehyde latex (RFL) layer or a rubber adhesive layer. Generally, an adhesive layer is applied by immersing the fiber layer or fibers in the adhesive layer solution. The fibrous layer or fibers are then passed through a squeeze roll and dryer to remove excess liquid. The adhesive layer is typically cured at 150 ° C to 200 ° C.

Adhesion promoters may also be incorporated into the skin layer (second layer and / or third layer) of the fiber or applied to the fiber and / or the fiber layer is a free upright film. Thermoplastic films of this category consist of various polyamides and their copolymers, polyolefins and their co-polyolefins, polyurethanes and methylmethacrylic acid. Examples of these films include 3M ™ 845 films, 3M ™ NPE-IATD 0693, and Nolax ™ A21.2242 films.

The fibers can be made in any suitable manner or method. There are two preferred methods of making reinforced rubber products. The first is disclosed by slit extrusion of a polymer to form a fiber (in one embodiment, the fiber is a tape element having a square or rectangular cross section). The die typically contains 5 to 60 slits, each slit forming a fiber (tape element). In one embodiment, each slit die has a width of about 15 mm to 50 mm and a thickness of about 0.6 to 2.5 mm. The fiber, once extruded, typically has a width of 4 to 12 mm. The fiber with one layer may be extruded, or the fiber may have a second layer and / or a third layer using coextrusion.

Next, the fibers are uniaxially drawn. In one embodiment, the fibers are preferably drawn at a ratio of at least about 5 to produce fibers having a modulus of at least about 2 GPa and a density of at least about 0.85 g / cm ³ .

Once the fibers are produced, the second and / or third layers can be added to the fibers in any suitable manner, including but not limited to lamination, coating, printing, and extrusion coating. This can be done before or after the uniaxial orientation step.

In one embodiment, the drawing of the fibers creates voids in the fibers. In one embodiment, the voids formed are present in an amount of about 3-18% by volume. In other embodiments, the extrudate contains pore-inducing particles that cause voids in the polymers and fibers and / or cracks in the fiber surface.

The fibers are formed from a layer of fibers, including wovens, nonwovens, unidirectional fabrics, and knits. The fibers are then optionally coated with an adhesion promoter such as an RFL coating and at least partially embedded in the rubber (preferably fully embedded). In embodiments where the fiber contains cracks, it is preferred that the adhesive coating at least partially fill the cracks.

In the second method, the polymer is extruded into a film. The film may be extruded to have one layer or may have a second layer and / or a third layer using coextrusion. The film is then slits into a plurality of fibers. In one embodiment, the fiber is a tape element having a square or rectangular cross-sectional shape. Then, these fibers are uniaxially drawn. In one embodiment, the fibers are preferably drawn at a ratio of at least about 5 to produce a fiber having a modulus of at least about 2 GPa and a density of at least about 0.85 g / cm ³ .

Once the fibers have been produced, they can be added to the fibers in any suitable manner, including but not limited to lamination, coating, printing and extrusion coating, if a second layer and / or third layer is desired. This can be done before or after the uniaxial orientation step.

In one embodiment, drawing of the fibers causes voids to occur in the fibers. In one embodiment, the voids formed are present in an amount of about 3-18% by volume. In other embodiments, the extrudate contains a polymer and pore-inducing particles. When uniaxially oriented, this results in void formation in the fiber and / or causes cracks to form on the surface of the fiber.

The fibers are formed into a fibrous layer comprising wovens, nonwovens, unidirectional fabrics, and knits. The fibers are then optionally coated with an adhesion promoter, such as an RFL coating, and at least partially embedded in the rubber. In embodiments where the fiber contains cracks, it is preferred that the adhesive coating at least partially fill the cracks.

In one embodiment, the die for extruding the film or fiber has a rectangular cross section (top side, bottom side and two edge sides) in which at least one of the top or bottom side of the die has a serrated surface. This can produce a film having an advantageous surface structure or surface texture.

In other embodiments, the fibers are heat treated prior to forming the fibers into a fiber layer. Heat treatment of the fibers provides several advantages such as higher modulus, higher strength, lower elongation and especially lower shrinkage. Methods of heat treating fibers include induction heating such as hot air convection heat treatment, steam heating, infrared heating or stretching on a hot plate (all under tension).

Test Methods

Peel Test: The T-peel test was performed on an MTS tensile tester at a rate of 12 inches / minute. One end thereof (preferably rubber side) was fixed to the lower tongs and the fabric was fixed to the upper tongs. The peel strength of the fabric from the rubber was measured from the average force separating the layers. A release liner was added to the sample edge (1/2 inch) between the fiber and the rubber to facilitate the peel test.

The peel strength measured in this test represents the force required to separate a single fiber or a unidirectional array of fibers from the rubber. In all experiments, the fiber array is pulled 180 ° to the rubber sample. In all samples, the thickness of the rubber was about 3 mm.

Example

The present invention is now described with reference to the following non-limiting examples, where all parts and percentages are by weight unless otherwise indicated.

Example  One

Example 1 was a single filament nylon fiber having a circular cross-sectional shape of 240 μm in diameter. The nylon used was Nylon 6,6 available from Invista ™ as Nylon 6,6 SSP-72. The nylon was extruded from a slot die having 60 slots (each slot having a diameter of 1.1 mm). The nylon was extruded at 300 ° C. at a rate of 20 kg / hour. The resulting fibers were then cooled to 32 ° C. and uniaxially oriented at a draw ratio of five. The drawing was performed in a three stage drawing line with a draw ratio of 4, 1.25 and 1 in the first, second and third stages, respectively. The finished nylon fiber had a modulus of 1 GPa and a density of 1.14 g / cm ³ . The fibers were essentially free of voids or cracks in the fiber surface.

Resorcinol precondensates commercially available as Penacolite-2170 from Indspec Chemical Corporation and vinyl-pyridine latexes commercially available as Gentac VP 106 from Omninova Solutions. Single filament nylon fibers were coated with 25% by weight (coating weight) of dry fibers with the RFL formulation used. The coated fibers were then air dried and cured in an oven at 190 ° C. for 3 minutes. The cured fibers are then pressed onto a rubber (commercially available as RA306 in Akron Rubber Compounding) at a mold at 300 psi so that the entire surface of the fiber is embedded in rubber and these materials are pressed at 30 ° C. at 30 ° C. Cured for minutes. In order to cover 0.5 inch (1.27 cm) of rubber, seven fibers were placed 1.7 mm apart to form a unidirectional fiber layer. Peel tests were performed as described above and the peel strength was 77 lb _f / in. The resulting peeled fibers also had a small amount of rubber still attached. This showed some bond breakage of the rubber (breaking of rubber attached from the bulk rubber to the surface of the nylon fibers). This bond failure is typical when any open fabric or open fiber layer is embedded due to the open structure of the fabric (through which the rubber can flow, surround the fabric and adhere to other rubbers).

Example  2

Example 2 was a multifilament nylon fiber. To produce multiple filament fibers, Z twisted together two nylon fibers having a circular cross-sectional shape of 940 denier (made from nylon available under the trade designation T-728 from Kordsa Global) to Z-twisted 1880 denier Filament nylon was formed. The multifilament twisted fibers had a modulus of ³ GPa and a density of 1.14 g / cm ³ . The fibers were essentially free of voids or cracks in the fiber surface.

25% by weight (coating weight) of dry fibers in RFL blends using resorcinol precondensates commercially available as Phenacolite-2170 from Inspec Chemical Corporation and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions. Coated with multiple filament nylon fibers. The coated fibers were then air dried and cured in an oven at 190 ° C. for 3 minutes. The cured fibers were then embedded in rubber (commercially available as RA306 in Akron rubber compounding) so that the entire surface of the fiber was embedded in rubber and these materials were cured at 160 ° C. for 30 minutes. To cover 0.5 inch (1.27 cm) of rubber, seven fibers were placed 1.75 mm apart to form a unidirectional fiber layer. Peel tests were performed as described above and the peel strength was 59 lb _f / in. As in Example 1, similar bond breakage of the rubber was observed.

Example  3

Example 3 was a nylon film (not fiber) having a rectangular cross-sectional shape with a width of 25 mm and a height of 200 μm. The nylon used was Nylon 6,6 available from Invista ™ as Nylon 6,6 SSP-72. The nylon was extruded in a film die 4 "wide and 1 mm high. The nylon was extruded at a rate of 2 kg / hour at 300 ° C. The resulting film was then cooled to 32 ° C. and not drawn or oriented. It was easy to handle and difficult to handle resulting in a film that easily cracked The finished nylon film had a modulus of 500 MPa and a density of 1.14 g / cm ³ The film was essentially free of voids or cracks on the surface of the film. , Had a very high surface finish.

25% by weight (coating weight) of the film in RFL formulations using resorcinol precondensates commercially available as Phenacolite-2170 from Inspec Chemical Corporation and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions. The nylon film was coated. The coated film was then air dried and cured in an oven at 190 ° C. for 3 minutes. The cured film was then pressed onto rubber (commercially available as RA306 in Akron rubber compounding) so that the entire surface of the film was on one side of the rubber and these materials were cured at 160 ° C. for 30 minutes. Peel tests were performed as described above and the peel strength was 2 lb _f / in. One reason for this low value was that the RFL adhesive did not bond to the surface of the material and the film did not fully press onto the rubber surface (meaning that the surface of the film was not completely embedded in the rubber).

Example  4

Example 4 was a single layer nylon fiber having a rectangular cross-sectional shape with a width of 2 mm and a height of 75 μm. The nylon used was Nylon 6,6 available from Invista ™ as Nylon 6,6 SSP-72. The polymer was extruded from a slot die with twelve slots, each slot having dimensions of 25 mm by 0.9 mm. The nylon was extruded at 300 ° C. at a rate of 20 kg / hour. The resulting tape element was then cooled to 32 ° C. and uniaxially oriented at a draw ratio of 5-6. The drawing was carried out in a three stage drawing line with a drawing ratio of 4, 1.2 and 1.1 in the first, second and third stages, respectively. It is expected that the same modulus and intensity can be obtained even if the draw ratios are distributed differently throughout the draw band. For example, a modulus of 6 GPa can also be obtained when the draw ratio is 1.5, 3.3 and 1.1 in the first, second and third stages, respectively. The finished nylon tape element had a modulus of 6 GPa, a density of 1.06 g / cm ³ and a void volume of 8% by volume (volume basis) of the fiber. A micrograph of the fiber can be seen in FIG. 9. The voids extended discontinuously throughout the longitudinal section of the fiber. The pore size ranged from 50 to 150 nm in width and 0 to 5 μm in length. The density of the voids was 8% by volume. The fibers were essentially free of cracks in the fiber surface.

25% by weight (coating weight) of dry tape in RFL formulations using resorcinol precondensates commercially available from Inspec Chemical Corporation as Phenacolite-2170 and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions. The resulting nylon fibers (which are tape elements) were coated. The coated tape was then air dried and cured in an oven at 190 ° C. for 3 minutes. The coated fibers were then placed on rubber (commercially available as RA306 in Akron rubber compounding) in a unidirectional pattern with no gaps between the fibers, such that the resulting unidirectional fiber layer essentially covered the entire surface of the rubber. . These were cured at 160 ° C. for 30 minutes. To cover a rubber 0.5 inch (1.27 cm) strip, six rectangular fibers had to be laid. Peel tests conducted as described above showed rubber failure at 197 lb _f / in. Peel test force results were the forces required to break the rubber in the sample. When the peel test was performed, the fibers did not pull out of the rubber and the rubber broke. This indicates that the peel strength was greater than 197 lb _f / in, but the exact value could not be determined due to rubber breakage.

Example  5

Example 5 was the same as Example 4 except that the total draw ratio of the fibers was three. The finished nylon fiber had a modulus of 3.5 GPa, a density of 1.06 g / cm ³ and a void volume of 8% by volume (volume basis) of the fiber.

Example  6

Example 6 was the same as Example 4 except that the total draw ratio of the fibers was four. The finished nylon fiber had a modulus of 4.1 GPa, a density of 1.06 g / cm ³ and a void volume of 8% by volume (volume basis) of the fiber. Comparing Examples 4, 5 and 6, the modulus and strength appear to be proportional to the draw ratio.

Example  7

Example 7 was a single layer nylon fiber having a rectangular cross-sectional shape of 4 mm wide and 130 μm high. The polymer used was nylon 6,6 available from Invista ™ as nylon 6,6 SSP-72. The nylon was extruded from a slot die having twelve slots (each slot having dimensions of 25 mm by 0.9 mm). The nylon was extruded at 300 ° C. at a rate of 60 kg / hour. The resulting tape element was then cooled to 32 ° C. and uniaxially oriented at a draw ratio of 5-6. The drawing was carried out in a three stage drawing line with a drawing ratio of 3.1, 1.65 and 1.1 in the first, second and third steps respectively. The finished nylon tape element had a modulus of 800 MPa and a density of 1.14 g / cm ³ . The fibers were essentially free of voids or cracks in the fiber surface. Comparing the fiber of Example 7 to that of Example 4, the fiber of Example 7 was twice as wide and almost two thick, and in the same size slot die, the output was extruded three times. As mentioned above, the orientation of the fiber bundles is a driving factor of the origin of the voids in the fiber. The presence and uniformity of the pores along the transverse width of the oriented fiber depends on whether the complete polymer element is oriented in the drawing process along the machine direction. The lack of voids is due to the fact that no effective heat transfer has been made to completely orient them in the polymer element. Oriented and unoriented regions were obtained in the polymer tape.

25% by weight (coating weight) of dry tape in RFL formulations using resorcinol precondensates commercially available from Inspec Chemical Corporation as Phenacolite-2170 and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions. Nylon fibers were coated. The coated fibers were then placed on rubber (commercially available as RA306 in Akron rubber compounding) in a unidirectional pattern with no gaps between the fibers, such that the resulting unidirectional fiber layer essentially covered the entire surface of the rubber. . It was cured at 160 ° C. for 30 minutes. To cover a rubber 0.5 inch (1.27 cm) strip, six rectangular fibers had to be laid.

Example  8

The coated fibers of Example 4 were placed on rubber (commercially available as RA306 in Akron rubber compounding) in a unidirectional pattern with a 0.5 mm gap between the fibers so that the unidirectional fiber layer did not cover the entire surface of the rubber. Let go. It was cured at 160 ° C. for 30 minutes. Six rectangular fibers were placed on a rubber 0.5 inch (1.27 cm) strip. The release film was positioned between the fiber layer and the rubber at one edge for ease of peel test. Peel tests conducted as described above showed rubber breakage at 180 lb _f / in indicating that the peel strength was greater than this value. This value was approximately equal to the peel strength of the unidirectional fiber layer (Example 4) with no gaps between the fibers. Since this force is an index of the breaking strength of the rubber and depends on the thickness of the rubber, a slight variation in this value is inevitable.

Example  9

The nylon film of Example 3 was adhesively bonded to rubber (commercially available as RA306 in Akron rubber compounding) using a commercially available adhesive film as 3M 845 film at 3M. The adhesive film consisted of acrylic copolymer, pressure sensitive adhesive and vinyl carboxylic acid. The film was pressurized to the rubber so that the entire surface of the nylon film was not covered by the rubber (not embedded), then the sample was cured at 160 ° C. for 30 minutes. Peel tests were performed as described above and the peel strength was 27 lb _f / in, which is an increase in peel strength compared to Example 3 using RFL coated adhesive.

Example  10

The fiber of Example 10 was similar to the fiber of Example 4 but with void-induced particles added. Example 10 was a single layer nylon fiber having a rectangular cross-sectional shape with a width of 2 mm and a height of 75 μm. The polymer used was Nylon 6,6 available from Invista ™ as Nylon 6,6 SSP-72 and contained 7% by weight of nanoclays (closet) available from Southern Clay Company. The nylon was extruded from a slot die having twelve slots, each slot having dimensions of 25 mm by 0.9 mm. The nylon was extruded at 300 ° C. at a rate of 20 kg / hour. The resulting fibers (which are tape elements) were then cooled to 32 ° C. and uniaxially oriented at a draw ratio of 5-6. The drawing was carried out in a three stage drawing line with a drawing ratio of 4, 1.2 and 1.1 in the first, second and third stages, respectively. As mentioned in Example 1, the same modulus and strength could also be obtained even if the draw ratios were distributed differently throughout the draw band. The finished nylon fiber had a modulus of 6 GPa, a density of 1.06 g / cm ³ and a volume fraction of 8% by volume of the fiber. The pores of the fiber can be seen in the micrographs of FIGS. 10A and 10B. The voids extend discontinuously throughout the longitudinal section of the fiber. The size of the pores was 50 to 150 nm in width and 0 to 5 μm in length. The pore concentration was 8% by volume. The pores were similar in shape to those obtained without pore starting particles. The fibers also contained cracks on the fiber surface. The cracks present on the fiber surface were discontinuous along the fiber's longitudinal direction and their length was about 300 μm to 1000 μm. Cracks on the surface of the fibers can be seen in the micrographs of FIGS. 11, 12 and 13.

25% by weight (coating weight) of dry fibers in RFL blends using resorcinol precondensates commercially available as Phenacolite-2170 from Inspec Chemical Corporation and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions. Nylon fibers were coated. The coated fibers were air dried and cured in an oven at 190 ° C. for 3 minutes. The coated fibers were then placed on rubber (commercially available as RA306 in Akron rubber compounding) in a unidirectional pattern with no gaps between the fibers, such that the resulting unidirectional fiber layer essentially covered the entire surface of the rubber. . It was cured at 160 ° C. for 30 minutes. To cover a rubber 0.5 inch (1.27 cm) strip, six rectangular fibers had to be laid. The release film was positioned between the fiber layer and the rubber layer at one edge for ease of peel test. Peel tests conducted as described above showed rubber breakage at 197 lb _f / in, indicating that the peel strength was greater than this value.

Example  11

Example 11 was a polyester fiber having a rectangular cross-sectional shape with a width of 2 mm and a height of 60 μm. The polyester used was polyethylene terephthalate, commercially available as PET IV 60 from Nanya Plastics Corporation. The polyester was extruded from a slot die with twelve slots, each slot having dimensions of 25 mm by 0.9 mm. The polyester was extruded at 300 ° C. at a rate of 20 kg / hour. The resulting fibers were then cooled to 32 ° C. and uniaxially oriented at a draw ratio of 7-9. The drawing was carried out in a three stage drawing line with a drawing ratio of 3.4, 2.2 and 1 in the first, second and third steps respectively. The finished polyester tape element had a modulus of 8 GPa, a density of 1.20 g / cm ³ and a void volume of 8% by volume of the fiber. The fiber was essentially free of cracks on its surface.

The polyester fibers were coated by a two-step immersion procedure using a pre-immersion solution containing a commercial caprolactam blocked isocyanate with Grilbond IL-6 in EMS and then cured at 225 ° C. for 3 minutes. Then, resorcinol pre-condensates commercially available as Phenacolite-2170 at Inspec Chemical Corporation and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions were applied to 25% by weight of the dry tape (coating weight). It was immersed in the standard RFL formulation used. The coated fibers were then air dried and cured in an oven at 190 ° C. for 3 minutes. The coated fibers were then placed on the rubber (commercially available as RA306 in Akron rubber compounding) in a unidirectional pattern with no gaps between the fibers such that the resulting unidirectional fiber layer essentially covered the entire surface of the rubber. It was cured at 160 ° C. for 30 minutes. Six rectangular fibers had to be laid to cover a 0.5 inch (1.27 cm) strip of rubber. When the peel test was performed, the pulled fibers still had a large rubber mass attached. The peel test showed an adhesive strength of 120 lb _f / in showing the cohesive failure of the rubber.

Example  12

Example 12 was a single layer fiber blend of polyester and nylon 6 having a rectangular cross-sectional shape of width 1.5 mm and height 100 μm. The polyester used was polyethylene terephthalate sold as PET IV 60 by Nanya Plastics Corporation; The nylon used was Nylon 6,6 available from Invista ™ as Nylon 6,6 SSP-72. The polymer was extruded from a slot die with twelve slots, each slot having dimensions of 25 mm by 0.9 mm. The blend was physically mixed in a ratio of 90:10 (90% polyester and 10% nylon by weight) and extruded at 300 ° C. at a rate of 20 kg / hour. The resulting tape element was then cooled to 32 ° C. and uniaxially oriented at a draw ratio of 5-7. The drawing was carried out in a three stage drawing line with a drawing ratio of 3, 2 and 0.9 in the first, second and third steps respectively. It should be noted that for a variety of reasons, the final stage requires some oversupply. Overfeeding reduces the shrinkage and modulus relaxation (creep) of the fibers. It also increases the toughness of the fiber. It is expected that the same modulus and intensity can be obtained even if the draw ratio is distributed differently throughout the draw band. For example, a modulus of 10 GPa can be obtained even when the draw ratios are 1.5, 3.3 and 0.9 in the first, second and third steps, respectively. The finished polyester-nylon blended tape element had a modulus of 10 GPa and a density of 1.37 g / cm ³ .

The polyester-nylon blend fibers were coated by a two-step immersion procedure using a pre-immersion solution containing commercially available caprolactam blocked isocyanate with Grillbond IL-6 in EMS and then cured at 225 ° C. for 3 minutes. Then, resorcinol pre-condensates commercially available as Phenacolite-2170 at Inspec Chemical Corporation and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions were applied to 25% by weight of the dry tape (coating weight). It was immersed in the standard RFL formulation used. The coated tape was then air dried and cured in an oven at 190 ° C. for 3 minutes. The coated fibers were then placed on the rubber (commercially available as RA306 in Akron rubber compounding) in a unidirectional pattern with no gaps between the fibers such that the resulting unidirectional fiber layer essentially covered the entire surface of the rubber. It was cured at 160 ° C. for 30 minutes. Six rectangular fibers had to be laid to cover a 0.5 inch (1.27 cm) strip of rubber. Peel tests conducted as described above yielded values of 143 lb _f / in.

Example  13

Example 13 was a single layer fiber blend of polyester and nylon 6 6 with a rectangular cross-sectional shape of width 1.5 mm and height 100 μm. The polyester used was polyethylene terephthalate sold as PET IV 60 by Nanya Plastics Corporation; The nylon used was Nylon 6,6 available from Invista ™ as Nylon 6,6 SSP-72. The polymer was extruded from a slot die with twelve slots, each slot having dimensions of 25 mm by 0.9 mm. The blend was physically mixed at a ratio of 70:30 (70% polyester and 30% nylon by weight) and extruded at 300 ° C. at a rate of 20 kg / hour. The resulting tape element was then cooled to 32 ° C. and uniaxially oriented at a draw ratio of 5-7. The drawing was carried out in a three stage drawing line with a drawing ratio of 3, 2 and 0.9 in the first, second and third steps respectively. It should be noted that for a variety of reasons, the final stage requires some oversupply. Overfeeding reduces the shrinkage and modulus relaxation (creeping) of the fibers. It also increases the toughness of the fiber. It is expected that the same modulus and intensity can be obtained even if the draw ratio is distributed differently throughout the draw band. For example, a modulus of 10 GPa can be obtained even when the draw ratios are 1.5, 3.3 and 0.9 in the first, second and third steps, respectively. The finished polyester-nylon blended tape element had a modulus of 10 GPa and a density of 1.37 g / cm ³ .

The polyester-nylon blend fibers were coated by a two-step immersion procedure using a pre-immersion solution containing commercially available caprolactam blocked isocyanate with Grillbond IL-6 in EMS and then cured at 225 ° C. for 3 minutes. Then, resorcinol pre-condensates commercially available as Phenacolite-2170 at Inspec Chemical Corporation and vinyl-pyridine latex commercially available as Gentak VP 106 from Omnova Solutions were applied to 25% by weight of the dry tape (coating weight). It was immersed in the standard RFL formulation used. The coated tape was then air dried and cured in an oven at 190 ° C. for 3 minutes. The coated fibers were then placed on the rubber (commercially available as RA306 in Akron rubber compounding) in a unidirectional pattern with no gaps between the fibers such that the resulting unidirectional fiber layer essentially covered the entire surface of the rubber. It was cured at 160 ° C. for 30 minutes. Six rectangular fibers had to be laid to cover a 0.5 inch (1.27 cm) strip of rubber. Peel tests conducted as described above yielded values of 143 lb _f / in.

All references cited herein, including publications, patent applications, and patents, are incorporated herein by reference to the same extent as if each reference was individually and specifically incorporated by reference and the entire contents of which are set forth herein. .

In describing the present invention (particularly with regard to the following claims), the use of the singular and similar citations should be considered to encompass both the singular and the plural unless the context clearly dictates otherwise or otherwise clearly contradicts the context. The terms "comprising", "having", "comprising" and "comprising" are to be considered as endless terms (ie, meaning "including but not limited to") unless otherwise indicated. The citation of a range of values herein is intended to serve as a shorthand method of simply quoting each individual value within that range unless otherwise indicated herein, with each individual value as if it were individually cited herein. Included in the specification. All methods described herein should be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary terms (eg, “such as”) provided herein is merely intended to better explain the present invention and does not limit the scope of the invention unless otherwise claimed. . Terms not used in the specification should be considered to refer to any non-claimed element essential to practicing the invention.

Preferred embodiments of the invention are described herein, including the best mode known to the inventors for carrying out the invention. Those skilled in the art will readily know variations on these preferred embodiments after reading the above description. We anticipate that such modifications will be made by those skilled in the art, where appropriate, and the inventors intend to practice the invention as otherwise described herein. Accordingly, the invention includes all changes and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. In addition, any combination of the elements described above in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims (19)

A reinforced rubber article comprising a rubber article and a layer of fiber embedded in the rubber article, wherein
The fibrous layer comprises a uniaxially drawn tape element having a rectangular cross section, an upper surface and a lower surface,
The tape element comprises a first layer having a draw ratio of at least about 5 or more, a modulus of at least about 2 GPa, a density of at least 0.85 g / cm ³ ,
Reinforced rubber article, wherein the first layer comprises a polymer selected from the group consisting of polyamides, polyesters and copolymers thereof. The method of claim 1,
Reinforced rubber article, wherein the first layer comprises a plurality of voids. The method of claim 1,
Wherein the fiber further comprises a plurality of crevices at least on the top or bottom surface of the fiber. The method of claim 1,
The rubber product is a tire,
The fiber layer is cap ply, carcass ply, chafer, flipper, clipper, body ply, shoulder ply, belt ply, belt separator ply, bead wrap A reinforced rubber product, which is a layer of tires selected from the group consisting of bead wraps and belt edge wraps. Slit extruding the tape element or extruding the film to slit into a plurality of tape elements;
Uniaxially orienting the tape element at a draw ratio of at least about 5 to form a uniaxially drawn tape element having a top surface and a bottom surface and having a modulus of at least about 2 GPa and a density of at least 0.85 g / cm ³ ;
Forming the uniaxially drawn tape element into a fiber layer; And
Embedding the fiber layer into rubber
Wherein the tape element has a rectangular cross section and at least a first layer, wherein the first layer comprises a polymer selected from the group consisting of polyamides, polyesters and copolymers thereof How to manufacture the product. The method of claim 5, wherein
The first layer further comprises void-initiating particles,
Uniaxially orienting the tape element comprises forming a plurality of voids. The method of claim 5, wherein
Uniaxially orienting the fiber creates a plurality of cracks on at least the top or bottom surface of the fiber,
Wherein the method further comprises coating the fiber with an adhesion promoter before or after forming the fiber into a fiber layer to at least partially fill the plurality of cracks of the fiber. A reinforced rubber article comprising a rubber article and a layer of fiber embedded in the rubber article, wherein
The fiber layer comprises uniaxially drawn fibers having at least a first layer, an upper surface and a lower surface,
The first layer comprises a polymer and a plurality of voids,
And the voids are present in an amount of about 3-18% by volume of the first layer. The method of claim 8,
Reinforced rubber article, wherein the first layer further comprises pore-inducing particles. The method of claim 8,
And the fiber further comprises a plurality of cracks on at least the top surface or the bottom surface of the fiber. The method of claim 8,
The rubber product is a tire,
The fiber layer is a layer of tires selected from the group consisting of cap plies, carcass plies, chafers, flippers, clippers, body plies, shoulder plies, belt plies, belt separator plies, bead wraps and belt edge wraps. Rubber products. The method of claim 8,
A reinforced rubber article, wherein the fibers have a rectangular cross section. The method of claim 8,
Reinforced rubber article, wherein the first layer comprises a blend of polyester and nylon 6. Slit extruding the tape element or extruding the film to slit into a plurality of tape elements, wherein the tape element has an upper surface and a lower surface and at least a first layer, wherein the first layer comprises a polymer ;
Uniaxially aligning the fibers to form uniaxially drawn fibers to form a plurality of voids in the first layer in an amount of about 3-18% by volume of the first layer;
Forming the uniaxially drawn fibers into a fiber layer; And
Embedding the fiber layer into rubber
A method of making a reinforced rubber product, which in turn comprises. 15. The method of claim 14,
And the fiber has a rectangular cross section. 15. The method of claim 14,
And wherein said polymer of said first layer comprises a polymer selected from the group consisting of polyamides, polyesters and copolymers thereof. 15. The method of claim 14,
And the first layer of fibers further contains void-inducing particles. 15. The method of claim 14,
Uniaxially orienting the fiber creates a plurality of cracks at least on the top or bottom surface of the fiber,
Wherein the method further comprises coating the fiber with an adhesion promoter before or after forming the fiber into a fiber layer to at least partially fill the plurality of cracks of the fiber. 15. The method of claim 14,
And the first layer comprises a blend of polyester and nylon 6.

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