JP5542005B2 - Sea-island fiber for rubber reinforcement - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a rubber reinforcing sea-island fiber, and more particularly to a highly adhesive and high physical property rubber reinforcing sea-island fiber suitably used for a rubber fiber composite.

  Polyester fibers represented by polyethylene naphthalate and polyethylene terephthalate as rubber reinforcing fibers have excellent physical properties such as high strength and high Young's modulus. Used as a rubber reinforcing fiber.

  However, polyester fibers have high hydrophobicity and low chemical activity on the polymer surface, and therefore have a problem of low adhesion to rubber. Moreover, it is known from the chemical characteristics of the polymer that the polyester fiber tends to deteriorate in strength when it is exposed to a high temperature in the presence of an amine and the ester bond is dissociated. In the case of a fiber for rubber reinforcement, adhesion is easily deteriorated by aminolysis in which the surface of the polyester fiber is deteriorated by an amine as an additive in the rubber.

Therefore, Patent Document 1 proposes a core-sheath type composite fiber for rubber reinforcement in which a dispersion layer is composed of an ethylene naphthalate polymer and a continuous layer is composed of a vinyl alcohol (PVA) polymer. By constituting the continuous layer with a vinyl alcohol polymer, the adhesion to rubber can be enhanced.
However, the vinyl alcohol fiber used for the sheath has a tendency to decrease in elastic modulus at high temperatures, tends to have a large variation in elastic modulus depending on temperature conditions, and has a problem of poor heat resistance.

JP 2002-235246 A

  The present invention has been made against the background described above, and it is an object of the present invention to provide a rubber reinforcing sea-island fiber having high physical properties and excellent adhesion.

  The sea-island fiber for rubber reinforcement of the present invention is a sea-island fiber in which the island component is composed of polyester and the sea component is composed of polyamide, and the number of islands composed of island components is 100 or more, and the weight ratio of the island component to the total weight is It is characterized by being 60% by weight or more.

  Furthermore, it is preferable that the polyester constituting the island component is polyethylene naphthalate, and the polyamide constituting the sea component is an aliphatic polyamide. Also, resorcinol / formalin / latex (RFL) adhesive is adhered to the surface of the sea island fiber, the diameter of the island component is in the range of 300 to 1000 nm, and the sea island fiber is a composite spun fiber. preferable. And it is preferable that a sea island fiber is a long fiber filament, or a sea island fiber is a short fiber of 50 mm or less in length.

  According to the production method of the present invention, it is possible to provide a rubber reinforcing sea-island fiber having high physical properties and excellent adhesion.

  The sea-island fiber for rubber reinforcement of the present invention is a sea-island fiber in which the island component is made of polyester and the sea component is made of polyamide. Examples of the polyester used for the island component include polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, and polybutylene terephthalate. Among them, the polyester component is preferably polyethylene naphthalate. Such island components have high elasticity and low shrinkage properties, are excellent in physical properties such as initial elastic modulus and dimensional stability, and are extremely effective for rubber reinforcement applications.

  Further, the polyamide used for the sea component is preferably an aliphatic polyamide, more specifically nylon 6, or nylon 6,6 having higher strength properties. Such polyamide fibers have slightly higher physical properties such as initial elastic modulus and dimensional stability than polyester of island components, but have sufficiently high physical properties among synthetic fibers, and have high surface chemical activity. It can exhibit excellent adhesive strength in rubber. In addition, it does not easily cause strong deterioration in rubber, has high adhesion stability, and effectively prevents strong deterioration of island component polyester.

  Further, the sea-island fiber for rubber reinforcement of the present invention requires that the number of islands made of polyester island components is 100 or more and the weight ratio of the island components to the total weight of the fibers is 60% by weight or more. In general, when the number of islands of sea-island fibers is increased, production tends to become unstable, so it is common to ensure stable productivity by decreasing the ratio of island components and increasing the ratio of sea components. However, in the present invention, the physical properties as reinforcing fibers are effectively improved by increasing the island components.

  The number of islands of the island component is preferably 100 or more, more preferably 400 to 1000. As the number of islands increases in this way, the contact area of each component of the sea island increases, and even if peeling occurs once because the area of each interface decreases, the peeling phenomenon does not propagate to other parts. Separation of each component of the fiber can be effectively prevented. Further, since the separation of each component does not occur, a polyamide component which is a sea component exists on the surface of the sea-island fiber, and the adhesive strength with a strong rubber is maintained and the deterioration of the polyester of the island component is prevented.

  When the number of island components is too small, interface peeling occurs due to an external force at the interface of each component, and the object of the present invention cannot be achieved. Conversely, if the number of island components is too large, not only the manufacturing cost of the spinneret increases, but the processing accuracy of the spinneret itself tends to decrease.

  The weight ratio of the island component to the total weight of the sea-island fiber of the present invention is essential to be 60% by weight or more, and the weight ratio of the island component to the sea component (island: sea) is 65:35. It is preferable to be in the range of ~ 95: 5. Thus, by increasing the weight ratio of the island component, the ratio of the island component that maintains the physical property of the yarn and the sea component that contributes to the adhesion is improved, and both the adhesive property and the physical property of the thread can be satisfied. When the sea component exceeds 40%, the island component is reduced, so that the elastic modulus and dimensional stability of the sea-island fiber are lowered, and it is not suitable for the rubber reinforcing fiber. On the contrary, when there are too few sea components, there exists a tendency for sufficient adhesiveness and durability not to be acquired.

  The diameter of the island component of the rubber reinforcing sea island fiber of the present invention is preferably 300 to 1000 nm. When the diameter of the island component is too thin, the fiber structure tends to be unstable, and the physical properties and fiber form become unstable, which is not preferable. On the other hand, when the diameter of the island component is too large, the area of the interface between the components of the sea-island structure becomes small, and peeling at the interface tends to occur.

  Moreover, it is preferable that the sea island fiber for rubber reinforcement of the present invention has a single yarn fineness in the range of 2 to 15 dtex. In addition, as a rubber reinforcing fiber, the sea-island fiber is a long-fiber filament in order to use its strength more effectively, and the sea-island fiber has a length of 50 mm or less, particularly easy to disperse and reduce anisotropy as much as possible. Is preferably a short fiber of 0.1 to 20 mm.

  Further, when the sea-island fiber is a long fiber filament, it is preferably a multifilament in which such sea-island structure single yarns are gathered. The total fineness of the multifilament is preferably 100 to 10,000 dtex. The number of filaments is preferably 50 to 1000. The strength is preferably 4.0 cN / dtex or more, and more preferably in the range of 4.5 to 12 cN / dtex. The initial elastic modulus is preferably 70 cN / dtex or more, and more preferably in the range of 75 to 800 cN / dtex.

  Furthermore, when reinforcing rubber | gum with a long fiber, it is preferable that it is the code | cord | chord form which such a multifilament gathered. In the case of the cord form, the total fineness of the cord is preferably 500 to 100,000 dtex. The number of filaments is preferably 100 to 5000 multifilaments. Such a cord is obtained by combining or twisting one or a plurality of multifilaments. The cord strength is preferably in the range of 2 to 10 cN / dtex.

  The cord using the sea-island fiber for reinforcing rubber of the present invention can be obtained, for example, by a method in which a multifilament made of sea-island fiber is previously twisted to form a lower twisted cord, and then combined and subsequently twisted (upper twist). .

  On the other hand, when the sea-island fibers are short fibers, the length is preferably 50 mm or less, and more preferably in the range of 0.1 to 20 mm. If the cut length is too short, cutting with sufficient accuracy tends to be difficult. Moreover, when the adhesive agent has adhered to the surface of the sea island fiber of this invention, it is preferable to cut, after making an adhesive agent adhere from the workability | operativity. In that case, if the length is too short, the ratio of the cut surface to which the adhesive is not attached increases, so that the reinforcing effect tends to be insufficient. Further, when the fiber length is too long, it tends to be entangled during handling and cannot be uniformly dispersed in the rubber, so that the performance of the original rubber reinforcing sea-island fiber tends to be hardly exhibited.

  The rubber reinforcing sea-island fiber of the present invention is preferably a composite spun fiber. In composite spinning, sea components and island components made of each polymer are joined together in a continuous state without interruption, and not only the fiber physical properties of each component are fully utilized, but also the sea component because it is difficult to peel off. Excellent protection of island components. Here, the composite spinning is performed using a composite spinning die in which a large number of nozzles are arranged in a predetermined pattern.

  Such a rubber reinforcing sea-island fiber of the present invention preferably further has a resorcin / formalin / latex (RFL) adhesive on its surface. Here, the RFL adhesive is an adhesive generally used for adhesion between rubber and fibers by adding a rubber latex to a resorcin / formalin condensate.

  Examples of rubber latex used in the RFL adhesive include natural rubber latex, styrene / butadiene rubber latex, vinylpyridine / styrene / butadiene copolymer latex, acrylonitrile / butadiene rubber latex, and chloroprene rubber latex. Are used alone or in combination. Among them, it is preferable to use vinylpyridine / styrene / butadiene copolymer latex alone or in combination. In the case of combined use, particularly excellent performance is exhibited when used in an amount of 1/3 or more of the total latex weight.

  The molar ratio of resorcin to formaldehyde in the adhesive is preferably in the range of 1: 0.8 to 1: 5, and more preferably in the range of 1: 1 to 1: 4. If the amount of formaldehyde added is too small, the crosslink density of the condensate of resorcin / formalin is lowered and the molecular weight is lowered. Therefore, the adhesive strength may be lowered by reducing the cohesive force of the adhesive layer. If the amount of addition is too large, the resorcin / formalin condensate becomes hard due to an increase in the crosslinking density, and compatibilization of the RFL with the rubber is inhibited during co-vulcanization with the adherend rubber, resulting in a decrease in adhesion and after treatment. This is not preferable because the fiber becomes extremely hard and the problems of reduced strength and fatigue occur.

  The blending ratio of resorcin / formalin to rubber latex in the adhesive is preferably a solid content ratio of resorcin / formalin: rubber latex in the range of 1: 3 to 1:20, particularly 1: 5 to 1: 1. Those in the range of 15 are preferred. If the ratio of the rubber latex is too small, the treated sea-island fibers become hard and the fatigue resistance tends to decrease, and the co-vulcanization with the rubber as the adherend becomes insufficient, and the adhesion may be lowered. On the contrary, if the ratio of the rubber latex is too large, it is not possible to obtain sufficient strength as an adhesive film. The tackiness of the fiber is remarkably increased, which causes contamination in the dip treatment process and contamination in the product manufacturing process, which is not preferable.

  Further, a crosslinking agent may be added to the RFL adhesive. Examples of the crosslinking agent include amines, ethylene urea, block polyisocyanate compounds and the like, but blocked polyisocyanate compounds are preferably used in view of the temporal stability of the treatment agent and the influence on the environment.

  The above-mentioned blocked polyisocyanate compound is an addition compound of a polyisocyanate compound and a blocking agent, and releases a block component by heating to produce an active polyisocyanate compound.

  Examples of the polyisocyanate compound include polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane triisocyanate, or two or more of these polyisocyanates and active hydrogen atoms. Terminal isocyanate group-containing polyol adduct polyisocyanate obtained by reacting a compound having, for example, trimethylolpropane, pentaerythritol, etc. with a molar ratio of isocyanate group (—NCO) to hydroxyl group (—OH) exceeding 1. Is mentioned. In particular, aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and polymethylene polyphenyl isocyanate are preferable because they exhibit excellent performance.

  Examples of blocking agents for blocked polyisocyanate compounds include phenols such as phenol, thiophenol, cresol, and resorcinol, aromatic secondary amines such as diphenylamine and xylidine, phthalimides, caprolactam, and valerolactam. Examples include lactams, acetoximes, methyl ethyl ketone oximes, oximes such as cyclohexane oximes, and acidic sodium sulfite.

  The addition ratio of the blocked polyisocyanate compound in the adhesive is 0.5 to 40% by weight, preferably 10 to 30% by weight, based on the solid content of resorcin / formalin / rubber latex (RFL). . When the addition amount is below the above range, the RFL cohesive energy cannot be improved to a sufficient level, and a good adhesive force tends not to be obtained. Further, when the addition amount exceeds the above range, the compatibility of the treatment agent with the rubber is lowered, the adhesive strength with the rubber is lowered, the fiber after the treatment is remarkably hardened, and the strength and fatigue tend to be lowered. It is in.

  Moreover, it is also preferable that the sea-island fiber for rubber reinforcement of the present invention has been previously treated with a pretreatment agent mainly composed of an epoxy compound, an isocyanate compound and a rubber latex before treating the RFL adhesive. It was obtained using a so-called two-bath treatment method.

  Such a pretreatment agent suitably used preferably contains a polyepoxide compound and / or a blocked isocyanate compound as a matrix component. In addition, it is preferable to contain a rubber latex since co-vulcanization with the rubber as the adherend is likely to occur, and high rubber attachment is realized during a peel test.

  As the polyepoxide compound, a compound containing 2 g equivalent or more of at least two epoxy groups per molecule per kg of the compound is preferable. Specifically, reaction products of polyhydric alcohols such as ethylene glycol, glycerol, sorbitol, pentaerythritol, polyethylene glycol and halogen-containing epoxides such as epichlorohydrin, resorcin, pis (4-hydroxyphenyl) dimethylmethane, phenol -Reaction products of polyhydric phenols such as formaldehyde resin, resorcinol-formaldehyde resin and the above halogen-containing epoxides, polyepoxide compounds obtained by oxidizing unsaturated compounds with peracetic acid or hydrogen peroxide, ie 3, 4 -Epoxycyclohexene epoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexenecarboxylate, bis (3,4-epoxy-6-methyl-cyclohexylmethyl) adipate, etc. It is possible. Among these, a reaction product of a polyhydric alcohol and epichlorohydrin, that is, a polyglycidyl ether compound of a polyhydric alcohol is preferable because it exhibits excellent performance.

  Similarly, the above-mentioned blocked polyisocyanate compound is an addition compound of a polyisocyanate compound and a blocking agent, and releases a block component by heating to produce an active polyisocyanate compound. More specifically, a blocked isocyanate compound used for the RFL adhesive may be mentioned.

  Examples of the rubber latex used in the pretreatment agent include natural rubber latex, styrene / butadiene rubber latex, vinylpyridine / styrene / butadiene copolymer latex, acrylonitrile / butadiene rubber latex, and chloroprene rubber latex. These are used alone or in combination. Among them, it is preferable to use vinylpyridine / styrene / butadiene copolymer latex alone or in combination. In the case of combined use, particularly excellent performance is exhibited when used in an amount of 1/3 or more of the total latex weight.

  The above-mentioned polyepoxide compound, blocked isocyanate compound, and rubber latex component are usually blended into the adhesive composition as an emulsion, aqueous dispersion, or aqueous solution. In order to obtain an emulsified liquid or an aqueous dispersion, for example, the compound is dissolved as it is or in a small amount of a solvent as necessary, and then a known emulsifier such as sodium alkylbenzenesulfonate, dioctylsulfosuccinate sodium salt, nonylphenol ethylene oxide. What is necessary is just to emulsify or disperse | distribute using an adduct etc.

  For the RFL adhesive and the pretreatment agent, it is preferable to use a dispersant, that is, a surfactant, when these components are used as an aqueous dispersion. The amount to be used is 0 to 15 wt%, preferably 10 wt% or less, based on the total solid content of the treatment liquid. If the amount exceeds the above range, the adhesiveness tends to decrease. The addition of a surface tension reducing agent such as alkylene glycol or water-soluble silicone is also effective, and these additions improve the wettability during processing, thereby improving the performance when processed at a low concentration.

The solid content of the RFL adhesive on the rubber reinforcing sea-island fiber of the present invention is preferably in the range of 1.0 to 20% by weight when applied alone with the RFL adhesive.
In addition, when the pretreatment agent is applied to the RFL adhesive in advance, the solid content adhesion amount of the RFL adhesive to the sea-island fibers is preferably in the range of 0.1 to 10% by weight. The amount is preferably in the range of 1.0 to 20% by weight.

In order to adhere these adhesives to the sea-island fibers, means such as contact with a roller, application by spraying from a nozzle, or immersion in a solution can be employed. Furthermore, in order to control the amount of solid content, it can be done by means of squeezing with a pressure roller, scraping with a scrubber, etc., blowing off with air blowing, suction, beater, etc. You may let them.
When the adhesion amount of these adhesives and pretreatment agents is small, sufficient adhesive strength cannot be obtained. When the adhesion amount is larger than the above range, the adhesive may fall off in the subsequent process, which causes a problem in post-workability.

  In order to obtain the sea-island fiber for rubber reinforcement of the present invention, the fiber is treated using such a treatment agent, and then dried and heat-treated at a temperature of 50 ° C. or higher and 10 ° C. or lower than the melting point of the fiber. It is preferable. More preferably, it is a method of drying and heat-treating in the temperature range of 180 to 250 ° C. for 0.5 to 5 minutes, preferably 1 to 3 minutes. If this drying / heat treatment temperature is too low, adhesion to rubber tends to be insufficient, and if the drying / heat treatment temperature is too high, the fiber melts and fuses, resulting in a significant decrease in strength and practical use. It tends to be lost.

  Such a sea-island fiber for reinforcing rubber of the present invention is a sea-island fiber in which the island component is composed of polyester and the sea component is composed of polyamide. The sea component polyamide is highly polar and has good adhesion to rubber, and the island component polyester is highly elastic and has low shrinkage properties. Have In particular, when aliphatic polyamide is used for the sea component and polyethylene naphthalate is used for the island component, both show high tan δ in the temperature range of 0 to 150 ° C., and the vibration applied as an external force is released as heat, It is a fiber for rubber reinforcement having a high vibration damping rate and excellent durability.

Further, the sea-island fiber for rubber reinforcement of the present invention has 100 or more islands composed of island components, and the weight ratio of the island components to the total weight is 60% by weight or more. The shrinkage characteristic can be exhibited better.
The sea-island fiber for reinforcing rubber of the present invention can be used as a knitted or braided yarn in addition to the cord as long as it is a long fiber filament. On the other hand, when used as a short fiber, it can be used in the form of felt, nonwoven fabric, spun yarn, or cut fiber.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the measurement of the characteristic in an Example was performed with the following measuring method.

(1) Initial peel adhesive strength This indicates the adhesive strength between the treatment cord and rubber. The cords are arranged at 30 / 2.54 cm (1 inch) and sandwiched between uncured rubber sheets containing a carcass composed mainly of 0.5 mm thick natural rubber. These sheets are stacked so as to be orthogonal, vulcanized at a temperature of 150 ° C. for 30 minutes at a pressing pressure (initial value) of 50 kg / cm ² , and then cut into strips along the cord direction. The force required to peel off the sheet along the strip of the prepared sample at a speed of 200 mm / min in the direction of 90 degrees with respect to the rubber sheet surface is shown by N / 2.54 cm (1 inch). .
Moreover, the area which the rubber | gum which remained on the surface has coat | covered the peeling surface was determined visually, and it was set as the rubber attachment.

(2) Heat-resistant adhesive strength A sample was prepared in the same manner as (1) except that vulcanization conditions were performed at 180 ° C. for 40 minutes (heat-resistant conditions), and the peel adhesive strength was measured to obtain the heat-resistant adhesive strength.

(3) Determination of short fiber dispersion state 100 g of a predetermined length cut fiber that had been previously subjected to adhesion treatment was added to 1 kg of natural / SBR unvulcanized rubber and kneaded for 10 minutes in a pressure kneader.
The rubber / fiber mixture was sheeted to a thickness of 0.4 mm with a mixing roll. The short fiber dispersion state in the sheet was visually determined, and the number of fiber aggregates having a diameter of 5 mm or more was counted. When 10 or more fiber aggregates existed within a 10 cm square, it was determined that the dispersion was poor.

(4) Preparation of sample for measuring strength and elongation of short fiber reinforced rubber composite The rubber sheet prepared by the method of (3) above has fibers arranged in the drawing direction. Therefore, the layers were aligned and overlapped, and press vulcanized to obtain a vulcanized rubber sheet having a thickness of 2 mm. A sample in a direction in which the tensile measurement in the fiber axis direction can be performed was cut out with a dumbbell No. 3 type, and used as a tensile test sample for measuring the strength and elongation.

(5) Tensile test of short fiber reinforced rubber composite Instron type tensile tester equipped with an extensometer that can directly measure the elongation between grades of the test piece of (4) previously cut into dumbbell No. 3 type. Installing. Then, a tensile test was performed at a distance between chucks of 50 mm and a pulling speed of 500 mm / min, and an initial elastic modulus and a yield point were evaluated.

[Example 1]
Nylon 66 is used as the sea component, and polyethylene naphthalate is used as the island component. A 1670 dtex 290 filament sea-island type composite fiber having an island part diameter of 800 nm, an island number of 800, and a sea: island area ratio of 30:70 is pre- A lower twist was applied at 10 cm, and two of them were combined, and an upper twist was applied at 40 T / cm to obtain a cord of 3340 dtex.
11 g of resorcinol and 26 g of 37% formalin were added to 450 g of water previously adjusted to be alkaline with sodium hydroxide, followed by aging at 20 ° C. for 10 hours.
To 150 g of water, 150 g of 40% vinylpyridine / styrene / butadiene terpolymer latex (Nippol 2518FS manufactured by Nippon Zeon Co., Ltd.) and 220 g of 40% styrene / butadiene latex (Nippol LX112 manufactured by Nippon Zeon Co., Ltd.) were added and made uniform. The resorcinol and formalin ripening solution were added to this solution to obtain an RFL adhesive.
The cord was dipped in the RFL adhesive using a contributor processing machine (CA Ritzler Co., Ltd., tire cord processing machine), then dried at a temperature of 130 ° C. for 2 minutes, and subsequently at a temperature of 230 ° C. For 1 minute. On the obtained treatment cord, 5.0% by weight was adhered as a solid content of the treatment agent. The obtained treated cord was embedded in an unvulcanized rubber containing carcass containing natural rubber as a main component and evaluated by the above method after vulcanization. The results are shown in Table 1.

[Example 2]
As in Example 1, 1 66 dtex 290 filament sea-island type using nylon 66 as the sea component and polyethylene naphthalate as the island component, having an island portion diameter of 800 nm, an island count of 800, and an area ratio of sea: island of 30:70. The composite fiber was pre-twisted at 40 T / 10 cm in advance, and two of these were combined and top twisted at 40 T / cm to obtain a 3340 dtex cord.
To 750 g of water, 10 g of sorbitol-type polyglycidyl ether (Nagase ChemteX Corp. Denacol EX611) and 30 g of sodium dioctyl sulfosuccinate (Daiichi Kogyo Seiyaku Co., Ltd. SW-30) 10 g are added, and high-speed stirring is performed. went. In contrast, 200 g of 40% vinylpyridine / styrene / butadiene terpolymer latex (Nippol 2518FS manufactured by Nippon Zeon Co., Ltd.) and 50 g of 40% block polyisocyanate (DM6400 manufactured by Meisei Chemical Co., Ltd.) were sequentially added, and a pretreatment agent was added. It was.
On the other hand, 11 g of resorcinol and 26 g of 37% formalin were added to 450 g of water previously adjusted to be alkaline with sodium hydroxide, followed by aging at 20 ° C. for 10 hours. To 150 g of water, 150 g of 40% vinylpyridine / styrene / butadiene terpolymer latex (Nippol 2518FS manufactured by Nippon Zeon Co., Ltd.) and 220 g of 40% styrene / butadiene latex (Nippol LX112 manufactured by Nippon Zeon Co., Ltd.) were added and made uniform. The resorcinol and formalin ripening solution were added to this solution to obtain an RFL adhesive.
The cord was immersed in the pretreatment agent using a contributor processing machine (tire code processing machine manufactured by CA Ritzler Co., Ltd.), then dried at a temperature of 130 ° C. for 2 minutes, and subsequently at a temperature of 230 ° C. Then, after being immersed in an RFL adhesive, it was dried at a temperature of 170 ° C. for 2 minutes, and subsequently heat-treated at a temperature of 230 ° C. for 1 minute. The obtained rubber reinforcing cord had 2.1% by weight of the pretreatment agent and 2.5% by weight of the RFL adhesive as the solid content of the treatment agent. The obtained treated cord was embedded in an unvulcanized rubber containing carcass containing natural rubber as a main component and evaluated by the above method after vulcanization. The results are shown in Table 1.

[Example 3]
Instead of using the sea-island fiber of Example 1, a 1670 dtex 290 filament sea-island type composite fiber having a diameter of an island portion made of polyethylene naphthalate of 650 nm, a number of islands of 1000, and an area ratio of sea: island of 40:60 is used. The same treatment as in Example 1 was performed to obtain a treated cord made of rubber reinforcing sea-island fibers. The evaluation results are also shown in Table 1.

[Comparative Example 1]
Instead of the sea-island fiber of Example 1, a 1670 dtex 290-filament sea-island composite fiber having a diameter of an island portion made of polyethylene naphthalate of 3.0 μm, the number of islands of 50, and a sea: island area ratio of 30:70 is used. Except for the above, the same treatment as in Example 1 was performed to obtain a treatment cord made of rubber reinforcing sea-island fibers. The evaluation results are also shown in Table 1.

[Comparative Example 2]
A rubber-reinforcing treatment cord was obtained by carrying out the same treatment as in Example 2 except that a polyethylene phthalate fiber of 1670 dtex 290 filament made of a single component was used in place of the sea-island fiber of Example 2. The evaluation results are also shown in Table 1.

[Example 4]
11 g of resorcinol and 26 g of 37% formalin were added to 450 g of water previously adjusted to be alkaline with sodium hydroxide, followed by aging at 20 ° C. for 10 hours.
To 150 g of water, 150 g of 40% vinylpyridine / styrene / butadiene terpolymer latex (Nippol 2518FS manufactured by Nippon Zeon Co., Ltd.) and 220 g of 40% styrene / butadiene latex (Nippol LX112 manufactured by Nippon Zeon Co., Ltd.) were added and made uniform. The resorcinol and formalin ripening solution were added to this solution to obtain an RFL adhesive.
Nylon 66 is used as the sea component, polyethylene naphthalate is used as the island component, a 1670 dtex 290 filament sea-island composite fiber having an island diameter of 800 nm, an island count of 800, and a sea: island area ratio of 30:70 After being immersed in the RFL adhesive using a treater (CA Ritzler Co., Ltd., tire cord processing machine), it is dried at a temperature of 130 ° C. for 2 minutes, and subsequently heat-treated at a temperature of 230 ° C. for 1 minute. Went. The obtained treatment cord had 5.5% by weight of RFL adhesive as a solid content.
The treated cord made of this rubber reinforcing sea-island fiber was cut into a length of 3 mm to obtain a short fiber of rubber reinforcing sea-island fiber to which an RFL adhesive was adhered. The short fiber was used to prepare a short fiber reinforced rubber composite, and then the strength and elongation were measured. The results are shown in Table 2.

[Example 5]
Instead of the sea-island fiber of Example 4, the same island part made of polyethylene naphthalate having a diameter of 650 nm, the number of islands is 1000, and the sea: island area ratio is 40:60 is 1670 dtex 290 as used in Example 1. Except for using a sea-island type composite fiber of filament, the same treatment as in Example 4 was performed to obtain a short fiber composed of a rubber reinforcing sea-island fiber that had been RFL-treated. The evaluation results are also shown in Table 2.

[Comparative Example 3]
Instead of the sea-island fiber of Example 4, the same island portion made of polyethylene naphthalate has a diameter of 3.0 μm, the number of islands is 50, and the sea: island area ratio is 30:70, as used in Comparative Example 1. The same treatment as in Example 4 was carried out except that the 1670 dtex 290 filament sea-island type composite fiber was used to obtain short fibers made of rubber-enhanced sea-island fiber subjected to RFL treatment. The evaluation results are also shown in Table 2.

[Comparative Example 4]
In place of the sea-island fiber of Example 4, the same treatment as in Example 4 was performed except that the same 1670 dtex 290 filament polyethylene naphthalate fiber as used in Comparative Example 2 was used, and an RFL-treated rubber A reinforcing short fiber was obtained. The evaluation results are also shown in Table 2.

Claims (8)

  The island component is a sea island fiber composed of polyester and the sea component is polyamide, wherein the number of islands composed of the island component is 100 or more, and the weight ratio of the island component to the total weight is 60% by weight or more. Sea island fiber for rubber reinforcement.   The sea-island fiber for rubber reinforcement according to claim 1, wherein the polyester constituting the island component is polyethylene naphthalate.   The sea-island fiber for rubber reinforcement according to claim 1 or 2, wherein the polyamide constituting the sea component is an aliphatic polyamide.   The sea-island fiber for rubber reinforcement according to any one of claims 1 to 3, wherein a resorcin-formalin-latex (RFL) adhesive is attached to the surface of the sea-island fiber.   The diameter of an island component is the range of 300-1000 nm, The sea island fiber for rubber reinforcement of any one of Claims 1-4.   The sea-island fiber for rubber reinforcement according to any one of claims 1 to 5, wherein the sea-island fiber is a composite spun fiber.   The sea-island fiber for rubber reinforcement according to any one of claims 1 to 6, wherein the sea-island fiber is a long fiber filament.   The sea-island fiber for reinforcing rubber according to any one of claims 1 to 6, wherein the sea-island fiber is a short fiber having a length of 50 mm or less.