MX2008007788A - Reinforcing glass fiber for rubber articles and process for production thereof. - Google Patents

Abstract

A reinforcing glass fiber for rubber articles which is excellent in the impregnation of glass fiber strands with an RFL treatment, is reduced in the swell of coats with the PFL treatment, has excellent appearance and physical performance, and little causes scatter of quality; and a process for the production of the glass fiber. The reinforcing glass fiber can be produced by impregnating a glass fiber strand composed of 200 to 2000 glass filaments not in an integrated state but in a separate state with an RFL treatment containing a rubber latex and a water-soluble resorcinol -formaldehyde condensate as the main components, setting the RFL treatment impregnated into the strand to form a coat, first-twisting the thus obtained coated glass fiber to form a first-twist yarn, and second-twisting at least two first-twist yarns thus obtained in the direction opposite to that of the first twisting.

Description

REINFORCEMENT GLASS FIBER FOR ARTICLES PE RUBBER AND PROCEDURE FOR THE PRODUCTION OF THE SAME TECHNICAL FIELD The present invention relates to a glass fiber for reinforcing rubber products, which is to be used as a reinforcing material for various rubber products, such as rubber tires or rubber bands, including timing bands; and a method for producing such a glass fiber.

TECHNICAL BACKGROUND It is common for a reinforcing glass fiber to be used to increase the strength or durability of various rubber products such as rubber tires or rubber bands, including timing bands, being coated with a membrane formed by a type of rubber. rubber type treatment agent, in order to increase the adhesion between the glass fiber and a rubber base material in a rubber product, and in order to increase the durability of the rubber product, protecting the glass fiber same As such a rubber-like treatment agent, a water-soluble treatment agent, comprising a condensate of resorcinol with formaldehyde, and a rubber latex, as the major components (hereinafter referred to sometimes as the "agent" of RFL treatment "), or a treatment agent having a rubber composition dissolved in a solvent (hereinafter referred to sometimes as a" rubber cement "). In addition, the above glass fiber to reinforce the rubber products is commonly produced by a production method that includes the following procedures (A) to (C). (A) A method for stretching together some strands of glass fiber obtained by forming a bundle with many glass filaments, while applying a sizing agent thereto, followed by drying, and impregnating an RFL treatment agent thereto. , and then solidifying the impregnated RFL treatment agent to the glass fiber strands, to form a coating layer, to thereby obtain a coated glass fiber. (B) A method for subjecting the coated fiberglass to twisted to form a twisted yarn. (C) A method for putting at least two twisted yarns together to form a folded yarn. Furthermore, in order to increase the adhesion between a reinforcing glass fiber and a rubber base material in a rubber product, it is also common to include the following procedure (D) in addition to the procedures (A) to (C) previous (D) A process for coating a rubber cement on the folded yarn surface, and then solidifying the rubber cement applied to the folded yarn to form a coating layer. Here, the fiberglass strand used in procedure (A) above is one prepared by forming bundles of 200 to 2000 glass filaments having a diameter of 3 to 10 μm. In addition, it has been common to stretch a plurality of such fiberglass strands together, and to impregnate an RFL treatment agent therein. That is, in the following Patent Document 1, it is described that a high strength glass strand is used prepared by forming a beam of 200 to 2000 high strength glass filaments having a diameter of more than 8 μm and at most 10 μm. pm, and from 1 to 10 such high strength fiberglass strands are stretched together and continuously introduced into the RFL treatment agent and impregnated therewith. Furthermore, in the following Patent Document 2, it is described that a high strength fiberglass strand prepared in a beam of 200 to 2000, preferably 300 to 600 high strength glass filaments having a diameter is used. from 3 to 6 pm, and from 1 to 10, preferably from 1 to 6, of such high strength fiberglass strands are stretched together to form a primary yarn of a specific yarn content, composed of 200 to 5000, preferably 800 to 2000 high strength glass filaments, whereby a coated layer made of the RFL treatment agent is formed on the surface of the primary yarn. Furthermore, in the following Patent Document 3, it is described that a high strength fiberglass strand prepared by forming a beam of 500 to 800 high strength glass filaments having a diameter of 6 to 8 μ is used, and from 1 to 8 such high strength fiberglass strands are stretched together. In addition, the following Patent Document 4 discloses a method of treating a glass fiber, wherein a strand having glass fiber filaments stretched together or a group of such strands, is immersed in a treatment agent, and then they are passed through at least one die to press and impregnate the treatment agent. In addition, the excess treatment agent on the surface of the above glass fiber is removed by at least one pair of rollers. Patent Document 1: JP-A-11 -217739 Patent Document 2: JP-A-11-158744 Patent Document 3: JP-U-1-111848 Patent Document 4: JP-A-9-25141 BRIEF DESCRIPTION OF THE INVENTION Problems to be solved by the invention As mentioned in the examples of each of the above Patent Documents, in a conventional process for producing a glass fiber to reinforce rubber products, it has been common to obtain a coated glass fiber, that 3 or more strands of glass fiber, each having a bundle of 200 to 400 glass filaments having a specific average diameter, are stretched together, and the RFL treatment agent is impregnated therein, followed by the solidification of the RFL treatment agent. However, by such a common procedure, when the plurality of glass fiber strands are stretched together and continuously introduced into a bath filled with the RFL treatment agent, to impregnate the RFL treatment agent with the strands of fiberglass, the surrounding area is probably included among the glass fiber strands, so that the impregnation of the RFL treatment agent to the glass fiber strands becomes insufficient, due to the presence of such included air, and The physical performance of the fiberglass finally obtainable to reinforce rubber products can sometimes be adversely affected. Furthermore, if the impregnation of the RFL treatment agent to the glass fiber strands is insufficient, the RFL treatment agent that is not completely impregnated will remain on the surface of the glass fiber strands, so that some portions will have an excess of RFL treatment agent, whereby when the RFL treatment agent is dried and solidified to form a coating layer, the excess RFL treatment agent can sometimes be blister to form a membrane with crust form. Such a blistered membrane will be detached by friction between the coated glass fiber and a guide or cursor, whereby the working medium will deteriorate, or the appearance of the fiberglass obtainable to reinforce rubber products will be damaged. A glass strand is usually rolled into a shape of a drum in a spiral body called a cake, and the glass strand is used when pulling out of such a cake. When the cake is heated to dry, the sizing agent applied to the glass strand will move to an inner section (towards the center of the spiral body), and an outer section of the cake, together with the evaporation of moisture, so there will be a phenomenon (commonly called migration), so that a large amount of the sizing agent is unevenly distributed in such sections of the fiberglass strand. The fiberglass strand having a large amount of the sizing agent in such sections, is relatively deficient in the impregnation of the RFL treatment agent, so that the above problem that occurs when the impregnation is insufficient tends to be more different. Therefore, a certain amount of the fiberglass strand in the innermost section and the outermost section of the cake, which has a large amount of the deposited sizing agent, needs to be removed and discarded, thus leading to a decrease in the performance. Furthermore, in the above procedure (A), when some fiberglass strands are stretched together, and the RFL treatment agent is impregnated thereto, a tension compensator such as a disk tensioner is used to stretch the fibers. respective fiberglass strands together, with uniform tension. In such a case, if a load applied by the disc tensioner is too large, the glass fiber strands will be damaged, and therefore, the load has to be made as small as possible. As a result, it is difficult to stretch the respective fiberglass strands together with uniform tension, and the tension will be distributed unevenly. Such non-uniform distribution of stress can sometimes adversely affect physical performance, particularly the tensile strength of the glass fiber finally obtainable to reinforce rubber products. Therefore, the object of the present invention is to provide a glass fiber to reinforce rubber products, which has an excellent appearance and physical performance, and which has little fluctuation in quality, where an RFL treatment agent is uniformly and sufficiently impregnates the fiberglass strand, and prevents an excess of RFL treatment agent from remaining on, and detaching from the surface of the fiberglass strand; and a method for producing such a glass fiber.

Means for solving the problems, In order to achieve the above object, the fiberglass to reinforce rubber products of the present invention, is a fiberglass to reinforce rubber products, which is obtained by bending at least two strands twisted, each obtained by twisting a coated glass fiber having a coating layer formed by the impregnation and solidification of an RFL treatment agent, comprising, as the main components, a rubber latex and a condensate soluble in water. resorcinol water with formaldehyde, where the coated glass fiber is a coated glass fiber having the coating layer formed by impregnating the RFL treatment agent to a single strand of glass fiber having from 200 to 2000 glass filaments in beam form, and solidify the impregnated agent. According to the glass fiber to reinforce rubber products of the present invention, the RFL treatment agent is impregnated into a fiberglass strand having from 200 to 2000 glass filaments in beam form, and solidifies to forming a coating layer, whereby the air is not included during the impregnation of the RFL treatment agent to the fiberglass strand, and the RFL treatment agent is impregnated uniformly and suitably between the respective filaments that they form the strand of fiberglass. Therefore, such fiberglass to reinforce rubber products will not have the possibility that a blistered membrane formed by an excess of RFL treatment agent will remain and detach, and will have an excellent appearance and physical performance. particularly excellent tensile strength. The fiberglass to reinforce rubber products of the present invention is preferably such that a coating layer of a treatment agent comprising a rubber and a solvent is further formed on the surface of the previous glass fiber obtained. by folding. It is therefore possible to increase its adhesion with a rubber base material in a rubber product. In addition, in the fiberglass to reinforce the rubber products of the present invention, the above fiberglass strand is preferably a strand of glass fiber having 500 to 1500 glass filaments in beam form. Therefore, it is possible to have an excellent impregnation of the RFL treatment agent to the fiberglass strand, while maintaining excellent productivity of the glass fiber strand in a fiber-forming process. Furthermore, with respect to the glass fiber for reinforcing rubber products of the present invention, the yarn count (g / km) and the cross section (mm2) preferably satisfy the ratio of the following formula (1), of most preferred way, they satisfy the relation of the following formula (2): 1450 < Thread count (g / km) / cross section (mm2) < 1900 1550 < Thread count (g / km) / cross section (mm2) < 1800 On the other hand, the method for producing a glass fiber to reinforce rubber products of the present invention, comprises an impregnation process (A), of impregnating an RFL treatment agent comprising, as the main components, a latex of rubber and a water-soluble condensate of resorcinol with formaldehyde, to a strand of glass fiber, and solidify the RFL treatment agent impregnated in the fiberglass strand to form a coating layer, whereby a coated fiberglass, a twisting process (B), of subjecting the coated glass fiber to twisted to obtain a twisted yarn, and a folding process (C) of putting at least two such twisted yarns together and subjecting them to folding , where in the impregnation process (A), as the fiberglass strand, one that has 200 to 2000 glass filaments in beam form is used, and the RFL treatment agent is impregnated to each fiberglass strand independently without stretching such fiberglass strands together. According to the method for producing a glass fiber to reinforce rubber products of the present invention, without stretching together a plurality of glass fiber strands having a specific number of glass filaments in beam form, the treatment agent of previous RFL is impregnated to each fiberglass strand independently, so that air is hardly included during the impregnation of the RFL treatment agent, and the impregnation status of the RFL treatment agent to the glass strand it's good. As a result, there will be no possibility that a membrane blistered by an excess RFL treatment agent will remain and peel off and the fiberglass obtainable to reinforce rubber products will have excellent appearance and physical performance. In addition, it is possible to avoid deterioration of the working medium in the twisting process. Furthermore, in the present invention, a plurality of glass fiber strands are not stretched together for the impregnation of the RFL treatment agent, and the tension between the glass fiber strands will not be uneven, so it is possible to provide a excellent resistance, particularly a tensile strength, of a fiberglass obtainable to reinforce rubber products, in order to improve the quality. The process for producing a glass fiber to reinforce rubber products of the present invention, preferably further includes an overcoating process (D) of applying a treatment agent comprising a rubber and a solvent on the surface of the folded yarn obtained. by the folding procedure (C) above, and then, the treatment agent applied to the folded yarn solidifies to form a coating layer. It is therefore possible to increase the adhesion with a rubber base material in a rubber product. Furthermore, in the method for producing a glass fiber to reinforce rubber products of the present invention, it is preferable to use, like the fiberglass strand above, a glass fiber strand having from 500 to 1500 glass filaments in beam shape. Therefore, it is possible to have an excellent impregnation of the RFL treatment agent to the fiberglass strand, while maintaining excellent fiberglass strand productivity in a fiber forming process.

EFFECTS OF THE INVENTION In accnce with the present invention, the impregnation of the RFL treatment agent to the glass fiber strand is excellent, whereby the coating layer rarely has blisters and crusts, and appearance and physical performance also They are excellent. In addition, the strength, particularly the tensile strength, of a glass fiber obtainable to reinforce rubber products is good and therefore it is possible to improve the quality.

BEST MODE FOR CARRYING OUT THE INVENTION The fiberglass reinforcing rubber products of the present invention is one obtained by subjecting to bending at least two twisted yarns of the coated glass fiber obtained by solidification of an RFL treatment agent to form a layer of a fiberglass film. coating, such an RFL treatment agent comprises, as the main components, a rubber latex and a water-soluble condensate of resorcinol with formaldehyde, and which is impregnated to each strand of glass fiber individually without stretching together a plurality of the strands of fiberglass.

The fiberglass strand to be used in the present invention is a fiberglass strand having from 200 to 2000 glass filaments in beam form. Specifically, a fiberglass strand having 500 to 1500 glass filaments in beam form is preferred from a viewpoint such that it is possible to have an excellent impregnation of the RFL treatment agent to the fiber strand. of glass, while maintaining excellent productivity of the fiberglass strand in a fiber-forming process. In addition, the fiberglass strand is preferably used after bundling the glass filaments by applying a sizing agent, comprising a silane coupling agent, a film forming agent, etc. The average diameter of the glass filaments is preferably 5 to 15 μm, more preferably 7 to 9 μm. In addition, the composition of the glass of which the glass filaments consist is not particularly limited, and may, for example, be E glass, S glass, etc. The RFL treatment agent to be used in the present invention is a composition comprising a rubber latex and a water-soluble condensate of resorcinol with formaldehyde (hereinafter "a water-soluble condensate of resorcinol with formaldehyde" will be referred to as "an RF condensate"), wherein an RF condensate and a rubber latex are mixed uniformly in water as a solvent, accng to a common method.

As the RF condensate to be incorporated into the RFL treatment agent, it is possible to use a water-soluble addition condensate rich in oxymethyl groups, obtained by reacting resorcinol with formaldehyde in the presence of an alkaline catalyst, such as a metal hydroxide. alkaline, ammonia or an amine, and is preferably an RF condensate obtained by a resorcinol-formaldehyde reaction in a molar ratio of 1 (0.3 to 2.5). The rubber latex to be combined with the RFL treatment agent may, for example, be a latex of a vinylpyridine / styrene / butadiene terpolymer, a latex of an acrylonitrile / butadiene / styrene terpolymer, a latex of a copolymer of acrylonitrile / butadiene, a latex of a modified copolymer of acrylonitrile / butadiene, a latex of a styrene / butadiene copolymer, a latex of a dicarboxylated styrene / butadiene copolymer, a polybutadiene latex, or a latex of a halogen-containing polymer . They can be used alone or in combination as a mixture of two or more thereof. Among them, a combination of a latex of a vinylpyridine / styrene / butadiene terpolymer (hereinafter referred to as "a vinylpyridine latex") with other rubber latexes is preferred, and is preferably a combination of a vinylpyridine latex with a latex of a halogen-containing polymer, from a point of view such that it is possible to improve the heat resistance, the flexural fatigue resistance or the water resistance of a rubber product finally obtainable such as a synchronization band, or the like. In addition, a halogen-containing polymer contained in the above latex of a halogen-containing polymer may, for example, be a chlorinated rubber, a chloroprene rubber or a chlorosulined polyethylene, and a chlorosulfonated polyethylene is particularly preferred. In addition, like the vinylpyridine latex, it is possible to use one commonly used for the treatment of a fiber to reinforce rubber products, and is preferably a latex obtained from a terpolymer having a vinylpyridine-styrene-butadiene content ratio of 10 to 20, 10 to 20, 60 to 80 in percent by mass. As such vinylpyridine latex, Nipol-2518FS (trademark, manufactured by ZEON CORPORATION) or Pyratex (trademark, manufactured by NIPPON A &; L INC.) Can, for example, be used appropriately. The ratio of the content of the RF condensate to the rubber latex in the RFL treatment agent is such that based on 100 parts by mass of the rubber latex, the RF condensate is preferably 1 to 40 parts by mass , particularly preferably from 2 to 15 parts by mass. Further, when a vinylpyridine latex is used in combination with other rubber latexes, such other rubber latexes are preferably 5 to 100 parts by mass, particularly preferably 10 to 30 parts by mass, based on 100 parts. mass of vinylpyridine latex. In addition, the relation of the previous content of the respective components is a mass ratio of their solid contents.

For the RFL treatment agent, as the case requires, it is possible to add a component that is commonly incorporated in a conventional RFL treatment agent, in addition to the RF condensate and the rubber latex. For example, a latex stabilizer or an anti-aging agent may be mentioned. The stabilizer may, for example, be aqueous ammonia or an aqueous solution of sodium hydroxide, and the anti-aging agent may, for example, be a liquid-type emulsified product of a mineral oil. The solids content, namely the concentration of the RFL treatment agent, is preferably 10 to 50% by mass, more preferably 20 to 40% by mass. If the above concentration is less than 10% by mass, the RFL treatment agent may not be impregnated in a sufficient amount to the fiberglass strand. If it is beyond 50% by mass, the stability of the RFL treatment agent will decrease, and the agent will tend to gel. The fiber for reinforcing rubber products of the present invention is one having a glass fiber strand coated with a coating layer (hereinafter also referred to as "the first membrane"), formed by the above RFL treatment agent. However, in order to further increase the adhesion with a rubber composition which will be the base material even a rubber product such as a tire or a rubber band, including a timing band, it is preferred that the first membrane be further cover with a coating layer (hereinafter also referred to as "the second membrane"), formed by the treatment agent comprising a rubber and a solvent (hereinafter referred to as "the overcoat treatment agent"). Such an overcoat treatment agent contains a rubber, as a main component, and can be obtained by dissolving, in a solvent, a rubber and other components that are incorporated as the case requires, according to a common method. The rubber to be used for the overcoat treatment agent may be a rubber used for a conventional rubber cement such as a halogen-containing polymer, an acrylonitrile / butadiene copolymer rubber (NBR) or a halogenated nitrile rubber (H). -NBR), etc. The halogen-containing polymer can be, for example, a chlorinated natural rubber, a chloroprene rubber, a chlorinated polyethylene, a chlorinated ethylene / propylene copolymer, a chlorinated polyvinyl chloride, a chlorosulfonated polyethylene or a chloro-brominated polybutadiene. As the solvent to be used for the overcoat treatment agent, it is possible to use an organic solvent. It may be, for example, xylene, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) or ethyl acetate. For the overcoat treatment agent, as the case may require, it is possible to incorporate a curing agent, an isocyanate, a resin, an additive, etc., in addition to the above rubber and solvent.

As the curing agent, for example, a polynitroso aromatic compound or a benzoquinone can be used. As the polynitroso aromatic compound, there may be mentioned, for example, p-dinitrosobenzene or poly p-dinitrosobenzene. The benzoquinone can, for example, be tetrachlorobenzoquinone, p-, p'-dibenzoylbenzoquinone dioxime or p-benzoquinone dioxime. Among them, it is preferred to use poly p-dinitrosobenzene, tetrachlorobenzoquinone, p-, p'-dibenzoylbenzoquinone dioxime or p-benzoquinone dioxime. As the above isocyanate, there can be used, for example, methylenediphenyl diisocyanate (MDI), toluene diisocyanate (TDI), triphenylmethane triisocyanate or naphthalene diisocyanate (NDI). However, an isocyanate monomer is highly volatile and is not preferred from the viewpoint of safety and handling efficiency. A polyisocyanate such as a dimer is preferred, which has a relatively small molecular weight and a high reactivity, and more preferably is a polyisocyanate having a degree of polymerization of 2 to 10. As the above resin, it is possible to use an uncured phenol resin or an uncured resin. epoxy not cured. The uncured phenol resin is uncured between the resins obtained from a phenol and an aldehyde, namely a phenol resin having reactivity for curing, and can, for example, be novolac or resole. In addition, an uncured epoxy resin is one that is not yet cured between the epoxy resins, that is, one that has reactivity for curing. The epoxy resin may, for example, be an epoxy resin of the bisphenol A type, an epoxy resin of the bisphenol F type, an epoxy resin of the phenol novolac type, or an epoxy resin of the cresol novolac type. As the above additive, there can be used, for example, a cure accelerator, a softener, an antioxidant, an inorganic filler commonly used as an additive for a rubber composition. As the inorganic filler, for example, silica or carbon black can be used. In addition, as the curing accelerator, for example, a curing accelerator of the maleimide type can be used. A preferred example of a component for an overcoat treatment agent used in the present invention may be a combination of a halogen-containing polymer, an isocyanate and a curing agent, or a combination of a rubber of an acrylonitrile copolymer. butadiene, an uncured phenol resin and an uncured epoxy resin. The solids content, namely the concentration of the overcoat treatment agent, is preferably 3 to 20% by mass, more preferably 5 to 15% by mass. If the above concentration is less than 3% by mass, the overcoat treatment agent may not be applied in a sufficient amount to the glass fiber strand. If it is beyond 20% by mass, the stability of the overcoat treatment agent may deteriorate. In addition, the glass fiber for reinforcing rubber products of the present invention can be coated with a coating layer (a third membrane) formed by a treatment agent containing the same rubber as the rubber base material in a rubber product. rubber, in order to increase the adhesion with the rubber composition as the base material for a rubber product, as described, for example, in JP-A-3-269177 or JP-A-7-190149 . Furthermore, with respect to the glass fiber for reinforcing rubber products of the present invention, the yarn count (g / km) and the cross section (mm2) preferably satisfy the ratio of the following formula (1), more preferably, they satisfy the relation of the following formula (2): 1450 < Thread count (g / km) / cross section (mm2) < 1900 (1) 550 < Thread count (g / km) / cross section (mm2) < 1800 (2) When a value obtained by dividing the yarn count (g / km) of the fiberglass to reinforce rubber products between the cross section (mm2) of the fiber is above the range, the cohesion between the twisted yarns constituting the fiber Glass to reinforce rubber products, will be strong, so that fiberglass to reinforce the rubber product will have excellent durability in water, because the penetration of water inside the fiber is avoided even if the fiber It is immersed in water, and the fiberglass to reinforce rubber products will be able to maintain good flexibility. By using such a glass fiber to reinforce rubber products, the water resistance of a rubber product finally obtainable such as a timing band will be good. Now, the method for producing a glass fiber to reinforce rubber products of the present invention will be described. The fiberglass to reinforce rubber products of the present invention is produced via an impregnation process (A) of impregnating an RFL treatment agent to a fiberglass strand, and then solidifying the impregnated RFL treatment agent. in the fiberglass strand, to form a coating layer, to thereby obtain a coated glass fiber, a twisting process (B) of subjecting the coated glass fiber to twisted to obtain a twisted yarn, and a folding procedure (C) of putting at least two such twisted yarns together and bending them. This is, first, in the impregnation process (A), a fiberglass strand to be coated, it is continuously introduced into a bath filled with the RFL treatment agent, and the RFL treatment agent adheres and impregnates the fiber. In addition, such fiberglass strand having the RFL treatment agent adhered, is continuously heated in a hot air oven of 200 to 350 ° C, followed by drying and solidification of the RFL treatment agent, for forming a first membrane, to thereby obtain a coated glass fiber having the first membrane.

The present invention is characterized in that in such a method of. impregnation, the fiberglass strands are not stretched together, but each strand is introduced independently to a bath filled with the RFL treatment agent, and the RFL treatment agent is impregnated thereto. In such an impregnation process, if a plurality of glass fiber strands were stretched together and introduced into a bath filled with the RFL treatment agent as in a conventional technique, they were introduced to the bath while the surrounding air was included in the bath. the strands of fiberglass, so that the agent tended to impregnate with the air, and small air bubbles tended to remain in the first membrane. As a result, a blistered portion would be formed in the first membrane, and such an ampouled portion would easily peel off. Especially, with respect to the fiberglass strand taken from the innermost or outermost section of the cake where the migration took place, it had a large amount of the sizing agent, so the impregnation of the RFL treatment agent it was deficient, and specifically, small air bubbles tended to remain, and blisters and crusts were likely to result. In addition, glass fiber to reinforce rubber products obtained by such a conventional technique, would be easily deficient in strength, particularly tensile strength, and was hardly able to stabilize the quality of the product.

When the RFL treatment agent is impregnated into the glass fiber strands, a uniform tension needs to be provided to pull the respective fiberglass strands together. NeverthelessIf the tension is too great, the fiberglass strands will be damaged, so that the physical performance can deteriorate, and the fibers can break. Therefore, the tension needs to be as small as possible, which means that it will be difficult to provide a uniform tension to the respective strands. As a result, it is considered that when tensile stress is exerted on the glass fiber to reinforce rubber products, the respective fiberglass strands that make up such a fiber can not resist stress in the same way. However, according to the production method of the present invention, the glass fiber strands do not stretch together, but are individually introduced to a bath filled with the RFL treatment agent. By impregnating the RFL treatment agent to each fiberglass strand individually, it is possible to impregnate the RFL treatment agent efficiently, and hardly any small air bubbles will remain in the first membrane. In addition, the tension in the fiberglass strand will not be uniform, so the tensile strength will be obtained sufficiently. In addition, it is possible to avoid the fluctuation of quality. In addition, since it is possible to have efficient impregnation of the RFL treatment agent, even in the fiberglass strand of an internal or external section of the cake having a large amount of the sizing agent due to migration, it is difficult Blisters and crusts are formed, and it is possible to improve the performance of the fiberglass strand. In addition, it is possible to reduce an installation space of a support (creel) for the cake, so that it is possible to reduce the size of the entire production device, and the installation space and the cost of the device will be reduced. In the present invention, the deposited amount of the first membrane to the coated glass fiber is preferably 12 to 25% by mass, more preferably 16 to 22% by mass, as the solids content, based on the mass of the coated fiberglass. If the deposited amount is less than 12% by mass, the individual glass filaments of the coated glass fiber tend to be inadequately covered by the first membrane, and the glass filaments probably come into contact with each other, and tend to to wear out by friction, so that the fatigue resistance due to curvature of the synchronization bands finally obtainable, etc. tends to be deficient. If the deposited amount exceeds 25% by mass, the flexibility of the membrane tends to be deficient, and also the resistance to bending fatigue of the rubber bands finally obtainable, etc. tends to be deficient. Next, in the twisting process (B), the coated glass fibers obtained in the above impregnation process are subjected individually or in combination of a plurality of them, to being twisted by a twisting machine such as a machine. of twisted with ring to obtain a twisted thread. The number of twists of the coated glass fiber in such a twisting process is preferably 0.5 to 4 twists / 25 mm. Otherwise, in the present invention, the coated glass fiber obtained in the above impregnation process can be captured once, and then the coated glass fiber can be subjected to twisting to obtain a twisted yarn, or fiberglass Coated obtained in the above impregnation process can be subjected to twisting without being caught, to obtain a twisted yarn. Next, in the folding process (C), at least two, preferably from 5 to 20, twisted yarns obtained in the above twisting process are put together, and are subjected to folding by means of a twisting machine such as a twisting machine with ring, or a flywheel machine to obtain a folded wire. The number of kinks in such a folding procedure is preferably 0.5 to 4 kinks / 25 mm. The twisting direction in the folding procedure is adjusted to be opposite from the twisting direction in the twisting procedure. In the present invention, after the folding procedure, it is preferred to carry out an overcoating process (D), wherein an overcoat treatment agent is applied on the surface of the above folded yarn, and the overcoat treatment agent applied to the folded yarn, solidifies to form a second membrane. By forming the second membrane, it is possible to improve the adhesion between the reinforcing glass fiber and a rubber composition as the base material for a rubber product. The second membrane can be formed in such a way that after the previous folding procedure, the folded wire is continuously dipped in a bath filled with the overcoating treatment agent, or the overcoating treatment agent is sprayed or coated on the surface of the folded yarn to have the overcoat treatment agent applied to the folded yarn. Next, the folded yarn is heated continuously in, for example, a hot air oven of 120 to 200 ° C to dry and solidify the overcoat treatment agent. At that time, the deposited amount of the second membrane to the reinforcing glass fiber is preferably 1 to 15% by mass, particularly preferably 3 to 10% by mass, as the solids content, based on the mass of reinforcing fiberglass. If the amount deposited is less than 1 mass%, the effect of increasing the adhesion between the reinforcing glass fiber and the rubber composition as the base material for the rubber products will probably be inadequate. Even if the amount deposited exceeds 15% by mass, the effect of increasing adhesion will not increase as much, and adhesion may be prevented instead.

In addition, in the present invention, it is preferred to appropriately select a method of the following methods (a) to (e), to adjust the yarn count (g / km) and the cross section (mm2) to satisfy the ratio of the following formula (1), it is more preferable to adjust them to satisfy the relation of the following formula (2): 1450 < Thread count (g / km) / cross section (mm2) < 1900 (1) 1550 < counting of threads (g / km) / cross section (mm2) = 1800 (2) (a) By appropriately adjusting the amounts that are incorporated of the respective components, particularly the amount of a vinylpyridine latex, of the RFL treatment agent to be impregnated into a fiberglass strand, appropriate adhesiveness will be provided ( the degree of adhesion of a coating layer made by the RFL treatment agent covering a coated glass fiber), to the coated glass fiber, and in the subsequent folding process, the coated glass fibers (the twisted yarns ), they will easily unite with each other. (b) In the impregnation process, by appropriately adjusting the temperature of a hot air oven to heat the glass fiber strand having the RFL treatment agent impregnated thereto, adequate adhesiveness will be provided to the coated fiberglass (c) In the folding procedure, the tension exerted on the respective plurality of twisted yarns to be twisted, is appropriately adjusted by a tension adjustment mechanism of a portion supplying the twisted yarn (commonly called creel) of the twisting machine for folding. (d) In the folding procedure, when a ring twisting machine is used, the number of revolutions of the pickup portion (commonly called spindle), is adjusted appropriately, and the weight and size of a slider to be used are selected appropriately. (e) In the folding procedure, when a flywheel machine is used, in order to place the twisted yarns to be a core material or a side material of a folded wire, as described in JP-A -2001-114906, a guide separating the yarn having small pores is used to individually introduce the respective twisted yarns, and a plurality of twisted yarns to form a folded yarn is therefore separated into a central material and a material side.

EXAMPLES Now, the present invention will be described in more detail with reference to the Examples. Here, in the following respective Examples, as an RFL treatment agent and an overcoating agent, the compounds are used by the following procedures.

Process for producing the RFL treatment agent To 100 parts by mass of a vinylpyridine latex (trademark: "Pyratex", manufactured by NIPPON A &L Inc.), 11.1 parts by mass of a chlorosulfonated polyethylene latex (trademark) commercial: "CSM450", manufactured by SUMITOMO SEIKA CHEMICALS CO., LTD), 6.7 parts by mass of an RF condensate (solids content: 7%) and deionized water, were mixed to obtain an RFL treatment agent that has a concentration of 30%. In addition, the above proportions of the respective components are proportions as solids content.

Overcoat treatment agent 10 parts by mass of a chlorosulfonated polyethylene (trademark: "Hypalon 40", manufactured by DuPont Dow Elastomers LLC), as a halogen-containing polymer, 5 parts by mass of polyisocyanate (trademark: "MR- 200", manufactured by NIPPON POLYURETHANE KK), 2 parts by weight of?,? '-dibenzoylbenzoquinone dioxin as a curing agent, 5 parts by mass of carbon black as an inorganic filler, and as a solvent, toluene, were mixed to obtain an overcoat treatment agent having a concentration of 10%.

EXAMPLE 1 600 glass filaments made of a high-strength glass (glass S), and having an average diameter of 7 μ? T ?, were beam formed while applying a sizing agent containing an amino silane coupling agent as the main component, and captured by a winding machine, followed by drying, to obtain a cake of a fiberglass strand having a mass of 3300 g. Next, the fiberglass strand was pulled from the innermost section of such a cake, and 500 m of each was pulled from each of the following sections (1) to (7). The pulled fiberglass strand of each section was individually and continuously immersed in a bath filled with an RFL treatment agent to have the RFL treatment agent deposited and impregnated into the fiberglass strand. Next, such a fiberglass strand was heated continuously for one minute in a hot air oven at a temperature of 250 ° C to dry and solidify the RFL treatment agent, to obtain a coated glass fiber having a coating layer (first membrane) made of the RFL treatment agent. Next, such coated fiberglass was captured using a ring twisting machine as a winding machine. In this way, 7 twisted yarns having a number of twists of 2 twists / 25 mm are obtained. Here, the deposited amount of the first anterior membrane was 18% as solids content, based on the mass of the twisted yarn. (1) The section where approximately 50 grams of the fiberglass strand was removed from the innermost section of the cake by pulling them (remaining amount of the cake: approximately 3250 g). (2) The section where approximately 150 grams of the fiberglass strand was removed from the innermost section of the cake by pulling them (remaining amount of the cake: about 3150 g). (3) The section where approximately 1300 grams of the fiberglass strand was removed from the innermost section of the cake by pulling them (remaining amount of cake: approximately 2000 g). (4) The section where approximately 2300 grams of the fiberglass strand were removed from the innermost section of the cake by pulling them (remaining amount of cake: approximately 1000 g). (5) The section where approximately 3050 grams of the fiberglass strand was removed from the innermost section of the cake by pulling them (remaining amount of the cake: approximately 250 g). (6) The section where approximately 3080 grams of the fiberglass strand were removed from the innermost section of the cake by pulling them (remaining amount of cake: approximately 220 g). (7) The section where approximately 3120 grams of the fiberglass strand were removed from the innermost section of the cake by pulling them (remaining amount of the cake: approximately 180 g).

COMPARATIVE EXAMPLE 1 200 glass filaments made of high strength glass (glass S) and having an average diameter of 7 μm, were beam formed while applying a sizing agent containing an amino silane coupling agent as the main component, and they were picked up by a winding machine, followed by drying to obtain a cake of a fiberglass strand having a mass of 3300 g. In addition, the fiberglass strand was pulled from the innermost section of each of the three cakes, and 500 m each was pulled from the same sections as Example 1 (7 sections from (1) to (7) ). The three strands of fiberglass were pulled together and continuously immersed in a bath filled with the RFL treatment agent to have the RFL treatment agent deposited and impregnated into the glass fiber strands. Then, such fiberglass strands were heated continuously for one minute in a hot air oven at a temperature of 250 ° C to dry and solidify the RFL treatment agent., to obtain a coated glass fiber having the first anterior membrane. Next, such coated fiberglass was captured using a ring twisting machine as a winding machine. In this way, 7 twisted yarns having a number of twists of 2 twists / 25 mm are obtained. Here, the deposited amount of the first anterior membrane was 18% as solids content, based on the mass of the twisted yarn.

EXAMPLE OF TEST 1 With respect to each of the 14 twisted yarns obtained in Example 1 and Comparative Example 1 above, the yarn count and the tensile strength were measured, and a value obtained by dividing the tensile strength between the yarn count , was used as an index for physical resistance. Furthermore, with respect to each of the twisted yarns, the evaluation of the degree of impregnation of the RFL treatment agent was carried out by the following method. The results are shown in Table 1.

Method to measure the tensile strength Using a tensile tester, the measurement of the breaking stress was carried out under conditions such that the distance of the nozzle was 250 mm, and the pulling speed was 250 mm / minute.

Evaluation of the degree of impregnation of the RFL treatment agent to the fiberglass strand 40 cm from a portion of the terminal end (winding terminal of the coil) of each of the twisted yarns was pulled and visually observed. The number of blisters or crusts (scab-shaped membrane or its portions, detached) in the first membrane was counted, and converted to a number per 10 cm. The smallest number was used as an index for the degree of impregnation of the RFL treatment agent to the fiberglass strand.

TABLE 1 Cake Example 1 Comparative Example 1 Section Quantity Quantity Count Resistance Strength Number Count Resistance Strength Number used remaining withdrawal of yarns to the yarn to the one of strand of cake (g / km) traction traction / ampoules (g ( km) traction traction / ampoules (g) (g) (N) count of (N) yarn count · [1] 50 3250 82.4 85.04 1.032 2 81 .6 80.22 0.983 1 1 [2] 150 3150 82.7 85.15 1 .03 1 80.5 79.02 0.982 7 [3] 1300 2000 78.6 91.79 1 .168 0.5 80 87.72 1.097 0.5 [4] 2300 1000 79.2 89.61 1 .131 0.5 80.7 86.45 1.071 0.5 [5] 3050 250 80.3 87.79 1.093 3.5 82.2 81 .1 0.987 7 [6] 3080 220 79.4 84.14 1 .06 3.5 81 .1 80.64 0.994 4.5 [7] 3120 180 83 84.01 1 .012 2 81.7 79.29 0.971 4 As shown in Table 1, it is evident that the twisted yarn of Example 1 which uses a single strand of glass fiber without stretching a plurality of them together, in the impregnation process, has a higher tensile strength in comparison with the twisted yarn in Comparative Example 1, using three strands of fiberglass stretched together. This is considered to be attributable to the fact that there is no problem of fluctuation in tension during the stretching of a plurality of fiberglass strands together. Furthermore, it is evident that when in Example 1, the fiberglass strand of the inner or outer section of the cake is used, the number of ampoules is small and the influence by migration is small. This is considered attributable to the fact that the impregnation of the RFL treatment agent to the glass filaments is improved. Thus, according to the present invention, the degree of impregnation of the RFL treatment agent to the fiberglass strand will be good. Especially, even with a fiberglass strand in a section of the cake it used to be difficult to impregnate the RFL treatment agent due to a large amount of a non-uniformly deposited sizing agent, the degree of impregnation of the RFL treatment will be good.

EXAMPLE 2 A cake of one strand of glass fiber (600 glass filaments in the form of a bundle) having a mass of 3300 g was obtained in the same manner as in Example 1. In addition, the fiberglass strand was pulled out a section wherein 200 g of the fiberglass strand was removed from the innermost section of the cake, pulling the strand (remaining amount of the cake: about 3100 g), and the strand was dipped individually and continuously into a bath filled with the RFL treatment agent to have the RFL treatment agent deposited and impregnated into the fiberglass strand. Thereafter, such fiberglass strand was heated continuously for one minute in a hot air oven at a temperature of 250 ° C to dry and solidify the RFL treatment agent, to obtain a coated glass fiber having a layer coating (first membrane) made of the RFL treatment agent. Next, such coated fiberglass was captured using a ring twisting machine as a winding machine. In this way, 500 m of 11 twisted yarns having a number of twists of 2 twists / 25 mm were obtained. Here, the deposited amount of the first anterior membrane was 18% by mass as a solids content, based on the mass of the twisted yarn.

Further, although such 11 twisted yarns were thrown together, the folding was carried out in the opposite twisted direction of the twist, to have a number of twists of 2 twists / 25 mm, using a twisting machine with different ring of the process of twisted, to obtain a folded thread. At that time, the weight of a slider used by the bending machine with ring for folding, was chosen appropriately among the commercially available, to adjust the ratio of the content of threads and the cross section of a glass fiber obtainable for Reinforce rubber products, so that it is in the range of formula (1) above. Next, such a folded yarn was continuously dipped in a bath filled with the above overcoat treatment agent, and the overcoat treatment agent was deposited on the folded yarn. After that, such a folded yarn was heated continuously for one minute in a hot air oven at a temperature of 130 ° C to dry and solidify the overcoat treatment agent, to form a coating layer (second membrane) made of the overcoat treatment agent, to thereby obtain a glass fiber to reinforce rubber products of Example 2. Here, the deposited amount of the second above membrane was 4% by mass as the solids content based on the mass of fiberglass to reinforce rubber products.

EXAMPLE 3 Using the same ring twisting machine and the conditions of Example 2, except for the use of a slider having a lighter weight by 28.6% than that used in Example 2, a folded wire was obtained by subjecting 11 twisted yarns obtained by the same method as in Example 2 to folding, while they are thrown together. At that time, when using the slider lighter than that used in Example 2, the ratio of the yarn count and the cross section of a fiberglass obtainable to reinforce the rubber products is outside the range of the formula (1 ) above (less than the value of the lower limit). Next, such a folded yarn was subjected to an overcoating process using the same treatment agent and conditions as in Example 2, to obtain the glass fiber to reinforce rubber products of Example 3.

COMPARATIVE EXAMPLE 2 Three fiberglass strand cakes (200 bundle-shaped glass filaments, respectively), each having a mass of 3300 g, were obtained in the same manner as in Comparative Example 1. Fiberglass to reinforce rubber products of Comparative Example 2 was obtained in the same manner as in Example 2, except that of the respective portions where 200 g of each of the glass fiber strands were removed. respectively of the innermost sections of the three cakes (remaining amount of each cake: 3100 g), three strands of fiberglass were pulled and stretched together, and continuously immersed in a bath filled with the RFL treatment agent to have the RFL treatment agent deposited and impregnated to the fiberglass strands.

EXAMPLE OF TRIAL 2 With respect to the fiberglass reinforcing rubber products obtained in each of Examples 2 and 3 and Comparative Example 2 above, the yarn count and the tensile strength were measured, and a value obtained by dividing the resistance The tensile between the count of threads was used as an index for physical resistance. In addition, the tensile strength after the boiling treatment was measured, and a ratio (a retention before and after boiling) between a tensile strength in an original state and a tensile strength after the treatment was calculated. boiling, and it was used as an index for water resistance. In addition, the cross section was calculated by measuring the diameter of the glass fiber to reinforce rubber products, and the yarn count was divided between the cross section, to obtain the relationship between the cross section and the yarn count. The results are shown in Table 2.

Method for measuring tensile strength in original condition Using a tensile tester, the measurement of breaking stress was carried out under conditions such that the distance of the nozzle was 250 mm, and the pulling speed was 250 mm / minute.

Method for measuring tensile strength after boiling treatment The fiberglass to reinforce rubber products was immersed in boiling deionized water for one hour, and then immersed in deionized water at room temperature for five minutes to cool. The water deposited on the surface of the fiberglass to reinforce rubber products was cleaned slightly, and then, using a tensile tester, the stress measurement was carried out at break under conditions such that the distance of the nozzle was 250 mm, and the pulling speed was 250 mm / minute.

Method for measuring the diameter Using a constant pressure thickness tester, four glass fibers to reinforce rubber products aligned in parallel without any space, were pressurized with a pressure of 226 g / cm2 for five seconds, and the thickness was measured as four of them aligned. It was referred to as a diameter.

TABLE 2 As shown in Table 2, Examples 2 and 3 have higher tensile strengths compared to Comparative Example 2. It is considered that in the Examples, the degree of impregnation of the RFL treatment agent to the fiber strand of Glass is good, and there is no fluctuation in tension during stretching of a plurality of fiberglass strands together, as in the conventional art. Furthermore, it is evident that Example 2 wherein the ratio of the yarn count and the cross section of the glass fiber to reinforce rubber products, satisfies the formula (1) above, is better in water resistance than Example 3, which does not satisfy the relation of formula (1) above. It is considered that the cohesion between the twisted yarns constituting the fiberglass to reinforce rubber products of Example 2 becomes higher, and the penetration of water into the fiber is prevented.

Industrial Applicability The reinforcing glass fiber of the present invention can suitably be used as a reinforcing material for various rubber products such as rubber tires or rubber bands, including timing bands. The entire description of Japanese Patent Application No. 2005-358718, filed on December 13, 2005, including the specification, claims and summary, is hereby incorporated by reference in its entirety.

Claims (8)

NOVELTY OF THE INVENTION CLAIMS

1. - A fiberglass for reinforcing rubber products, which is obtained by subjecting to folding at least two twisted yarns, each obtained by subjecting to twisted a coated glass fiber having a coating layer formed by the impregnation and solidification of an agent of RFL treatment, comprising, as the main components, a rubber latex and a water-soluble condensate of resorcinol with formaldehyde, wherein the coated glass fiber is a coated glass fiber having the coating layer formed by impregnating the agent of treatment of RFL to a single strand of glass fiber that has from 200 to 2000 filaments of glass in beam form, and to solidify the impregnated agent.

2. The glass fiber to reinforce rubber products according to claim 1, further characterized in that a coating layer made of a treatment agent comprising a rubber and a solvent, is further formed on the surface of the fiber of Previous glass obtained by folding.

3. The fiberglass for reinforcing rubber products according to claim 1 or 2, further characterized in that the previous fiberglass strand is a strand of glass fiber having 500 to 1500 glass filaments in the form of make.

4. - Fiberglass to reinforce rubber products in accordance with. claim 1 to 3, further characterized, because the yarn count (g / km) and the cross section (mm2), satisfy the relationship of the following formula (1): 1450 < Thread count (g / km) / cross section (mm2) < 1900 (1)

5. - The fiberglass for reinforcing rubber products according to claim 4, further characterized in that the yarn count (g / km) and the cross section (mm2) satisfy the ratio of the following formula ( 2): 1550 < Thread count (g / km) / cross section (mm2) < 1800 (2)

6. - A method for producing a glass fiber to reinforce rubber products, comprising an impregnation process (A) of impregnating an RFL treatment agent comprising, as the main components, a rubber latex and a water-soluble condensate of resorcinol with formaldehyde, to a fiberglass strand, and solidifying the impregnated RFL treatment agent to the glass fiber strand to form a coating layer, to thereby obtain a fiber of coated glass, a twisting process (B) of subjecting the coated glass fiber to twisted to obtain a twisted yarn, and a folding process (C) of putting at least two such twisted yarns together and subjecting them to folding, wherein in the impregnation process (A), such as the fiberglass strand, one is used which has 200 to 2000 glass filaments in beam form, and the RFL treatment agent is impregnated to each fiber strand of glass independently without stretching such fiberglass strands together.

7. The method for producing a glass fiber to reinforce rubber products according to claim 6, further characterized by including an overcoating process (D) of applying a treatment agent containing a rubber and a solvent to the surface of the folded yarn, obtained by the folding procedure (C) above, and then solidifying the treatment agent applied to the folded yarn which solidifies to form a coating layer.

8. The method for producing a fiberglass to reinforce rubber products according to claim 6 or 7, further characterized in that, as the fiberglass strand above, a glass fiber strand having 500 to 1500 glass filaments in beam form.