JP5080512B2 - Manufacturing method of reinforcing fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing fiber having strong adhesiveness to sufficiently reinforce a polymer by uniform adhesion even with a small coating weight of a treatment agent. <P>SOLUTION: The method for producing a reinforcing fiber includes immersing the fiber in a treatment solution. The fiber is a fiber composed of a multifilament. After the adhesion A of the treatment solution to the fiber, the fiber is kept in an unheated state at 50&deg;C or less for not less than 30 seconds and then drying-heat treatment C is carried out. During the retention in the unheated state B, preferably the fiber is changed in direction by a roll, the fiber is a twisted cord and is a polyester fiber. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a reinforcing fiber, and more particularly to a method for producing a reinforcing fiber that is suitably used for a polymer / fiber composite and in which a treatment liquid is efficiently attached to the fiber surface.

  Fiber materials have been widely used for polymer reinforcement, more specifically for rubber reinforcement of tires, hoses, belts and the like. Thus, when using a fiber for a reinforcement use, adhesion | attachment between various materials and fibers is an important subject, and various adhesive agents have been developed. However, when synthetic fibers having excellent physical properties are used, there is still a problem that adhesiveness is still insufficient as compared with the strength of the fibers. In particular, polyester fibers such as polyethylene terephthalate and polyethylene naphthalate fibers, and aromatic polyamide fibers have excellent physical properties such as high strength and high Young's modulus, making them ideal as reinforcing fibers. However, since the surface of these fibers is relatively inactive, there is a problem that the adhesiveness to the polymer matrix becomes insufficient with a normal adhesive.

  For this reason, particularly in the field of rubber reinforcing fibers, chemical treatment methods for treating the surface of the fiber with various chemicals, for example, highly reactive chemicals such as aliphatic epoxy compounds, ethylene urea, blocked isocyanate compounds, etc. A two-bath treatment method in which treatment with a resorcin / formalin / rubber latex (RFL) adhesive is performed after treatment to improve the adhesion of the fiber surface has been proposed and put into practical use (for example, Patent Document 1). Furthermore, various methods are known, such as a treatment method for reducing the adhesion amount of an adhesive by, for example, containing a compound having a vinyl halide group in the first bath as in Patent Document 2.

  An important purpose of the treatment liquid first treated directly attached to the fiber surface is to activate the fiber surface. That is, basically, a compound that activates the fiber surface is required to be arranged on the fiber surface. On the other hand, when the treatment liquid or the treatment agent is excessively attached and has an unnecessarily thick thickness, it tends to be non-uniform, and the physical strength of the agent film itself is required after drying, and the strength of the agent film is insufficient. there were. Therefore, conventionally, as a method for forming a thin film on the fiber, a method of applying a dilute processing solution, a method of improving the wettability of the fiber surface with a surfactant, and the like have been adopted.

  However, when a dilute processing solution is used, there is a problem that the surface tension is likely to increase, and defects are likely to occur in the formed film. In addition, there is a problem that the surfactant often has a negative effect of inhibiting adhesion as well as improving wettability.

JP-A-54-73994 JP 2000-234275 A

  It is an object of the present invention to provide a reinforcing fiber having strong adhesiveness that can sufficiently reinforce a polymer when the treatment agent is adhered uniformly at least.

  The method for producing a reinforcing fiber of the present invention is a method for producing a reinforcing fiber by immersing the fiber in a treatment liquid, wherein the fiber is a multifilament fiber, and the treatment liquid is attached to the fiber. It is characterized in that it is kept for 30 seconds or more in an unheated state at 50 ° C. or lower, and then dried and heat treated.

  Further, it is preferable that the fiber is changed in direction by a roll during holding in an unheated state, the fiber is a twisted cord, and the fiber is a polyester fiber.

  The treatment liquid is a pretreatment liquid having a viscosity of 1 to 5 mPa · s, and is further treated with an adhesion treatment liquid mainly containing a resorcin / formalin / rubber latex (RFL) adhesive after drying and heat treatment. Further, the pretreatment liquid is composed of only a crosslinking agent and an emulsifier, and the adhesion treatment liquid contains a crosslinking catalyst, or the crosslinking agent is a reaction between a polyhydric alcohol or a polyhydric phenol and a chlorine-containing epoxide. It is preferable that the product is a product and the crosslinking catalyst is a block polyisocyanate.

  According to the production method of the present invention, there is provided a reinforcing fiber having a strong adhesive property that can sufficiently reinforce a polymer when the treatment agent is adhered uniformly at least.

It is a schematic diagram of the manufacturing method of this invention.

  Although there is no restriction | limiting in particular as a fiber used for this invention, It uses especially preferable for synthetic fibers, such as a polyester fiber and an aromatic polyamide fiber. More specifically, for example, as a polyester fiber, a fiber made of polyester having terephthalic acid or naphthalenedicarboxylic acid as a main acid component and ethylene glycol, 1,3-propanediol, or tetramethylene glycol as a main glycol component is used. I can list them. Representative examples of the aromatic polyamide fiber include polyparaaminobenzamide, polyparaphenylene terephthalamide, polyparaaminobenzhydrazide terephthalamide, polyterephthalic acid hydrazide, polymetaphenylene isophthalamide, and copolymers thereof. Can be mentioned.

  The form of the fiber to be subjected to the treatment of the present invention is not particularly limited as long as it is a fiber made of multifilament, and includes various fiber assembly forms such as yarn, cord, nonwoven fabric, and woven or knitted fabric. The cord that has been used is preferable in order to more effectively exhibit the strength of the fiber. It is because it is possible to adjust the permeability with respect to the subsequent treatment liquid by being twisted. More specifically, the number of twists is preferably in the range of 30 to 50 turns / m, and from the viewpoint of stabilizing the twisted structure, it is preferable that the number of twists is double twisted rather than single twisted. When the number of twists is too small, the treatment liquid penetrates too much into the inside of the cord, and there is a tendency for the effect of improving the adhesive strength to be reduced when the amount is the same. On the other hand, when the number of twists is too large, the treatment liquid is hardened on the cord surface and cannot uniformly adhere to the fiber surface, and the effect of improving the adhesion tends to decrease.

  There are no particular limitations on fiber denier, number of filaments, cross-sectional shape, fiber properties, microstructure, polymer properties (terminal carboxyl group concentration, molecular weight, etc.), presence or absence of additives in the polymer, etc. In order to make effective use of strength, it is preferable to have a circular cross-sectional shape. As long as the multifilament is 10 filaments or more, the effect of the present invention can be seen, but it is preferably 100 to 1000 filaments, more preferably 150 to 500 filaments. Moreover, it is also preferable that the fiber subjected to the treatment of the present invention has been subjected to a pre-adhesion treatment in advance at the spinning stage.

  Now, in the method for producing reinforcing fibers of the present invention, the above-described multifilament fibers are immersed in a treatment liquid. The treatment liquid preferably has a viscosity in the range of 1 to 5 mPa · s. If the viscosity is too high, the effect of holding in an unheated state, which is the greatest effect of the present invention, tends to be difficult to be exhibited. In order to adhere the treatment liquid to the fiber, it is possible to employ means such as contact with a roller, application by spraying from a nozzle, or immersion of the fiber in the solution. Moreover, the solid content adhesion amount to the fiber is preferably in the range of 0.1 to 2% by weight. In order to control the amount of solids adhered to the fiber, it can be performed by means of squeezing with a pressure roller, scraping with a scrubber, etc., blowing off with air blowing, suction, beater, etc. It may be attached.

  The first feature of the production method of the present invention is that the pretreatment liquid adheres uniformly even though the amount of the pretreatment liquid is small. Therefore, in order to effectively exhibit the effect, the adhesion amount is preferably 2% by weight or less. On the contrary, if the amount of adhesion is so small that the surface of the fiber cord cannot be sufficiently covered, even if the method of the present invention is used, the effect of improving the adhesiveness is reduced. Therefore, the adhesion amount is preferably 0.1% by weight or more.

  In the manufacturing method of the reinforcing fiber of the present invention, the treatment liquid is attached to the fiber by dipping treatment with the treatment liquid, and then kept in an unheated state at 50 ° C. or lower for 30 seconds or more, and then dried and heat-treated. Furthermore, the unheated state is preferably 0 ° C. or higher and 40 ° C. or lower, and usually room temperature or higher.

  When the heat treatment is performed immediately after immersing the treatment liquid in the fiber as in the prior art, the treatment liquid adheres to the fiber surface evenly before being diffused, and the adhesive strength is not improved. In the present invention, it was surprisingly found that the treatment agent uniformly adheres to the surface of the fiber and improves the fiber adhesive force only by holding it for 30 seconds or more in an unheated state of 50 ° C. or less. is there. Furthermore, it is preferable to hold for 0.5 to 5 minutes. If the holding time is short, the treatment agent is hardened only on the surface layer of the fiber bundle composed of multifilaments, which is not preferable. Further, if the holding time is too long, not only the productivity is lowered, but also the concentration of the treatment agent is changed and the stable productivity tends to be lowered.

  Moreover, it is preferable that the direction of the fiber is changed by a roll while holding the fiber made of multifilament in an unheated state. It is possible to adjust the degree of penetration of the treatment agent into contact with the roll. Moreover, it is preferable that the fiber to which the treatment agent is attached is held in a horizontal state parallel to the ground, that is, in a horizontal state as the yarn path. When it is parallel to the ground, the treated liquid is likely to diffuse inside the multifilament, and the fibers can be treated more uniformly.

  As described above, the present invention can be uniformly attached to the surface by holding it for 30 seconds or more in an unheated state. The film formation on the fiber surface becomes uniform over time, and an excessive agent can penetrate into the fiber bundle made of multifilaments, so that an ideal treatment liquid film can be easily formed on the fiber surface. .

  And the manufacturing method of the fiber for rubber reinforcement of the present invention is such that after the treatment liquid is attached to the fiber, it is kept in an unheated state at 50 ° C. or lower for 30 seconds or more, and then dried and heat-treated. .

  As the drying step, it is preferable to carry out preliminary drying at a temperature higher than 50 ° C. after holding the fiber in an unheated state, but it can be omitted in the present invention. Preliminary drying is performed in order to prevent migration more effectively. However, in the present invention, since it is held in an unheated state at 50 ° C. or lower in advance, uniform processing can be performed without preliminary drying. Because.

As the heat treatment, it is preferable to perform the heat treatment for 30 seconds to 5 minutes at a temperature of 220 to 260 ° C. after drying it gradually in several stages. By sufficiently performing the high-temperature treatment in this manner, moisture in the treatment liquid can be removed and uniformly adhered to the fiber surface, and non-uniformity can be prevented at a higher level. . If the drying and heat treatment temperature and time are too low, the adhesive strength of the reinforcing fiber, which is the final product, tends to be insufficient, and if the drying and heat treatment temperature is too high, the fiber itself melts and fuses. This is undesirable because it causes a decrease in strength.
The reinforcing fiber obtained by such a production method of the present invention is a fiber having a high adhesion performance with few defects due to the uniform attachment of the treatment liquid, and is optimally used for reinforcing applications.

  Moreover, as a processing liquid used by this invention, it is preferable that the viscosity of a processing liquid does not change in the process of leaving in an unheated state. From this point of view, it is preferable that the treatment liquid does not contain a component that causes a sudden change in viscosity or an increase in viscosity due to drying of latex or the like. However, for example, a resorcinol / formalin / rubber latex (RFL) adhesive is representative for bonding rubber reinforcing fibers, and rubber latex is an essential component. Therefore, in the present invention, it is preferable that the pretreatment liquid for the first bath in direct contact with the fiber does not contain a component such as rubber latex, and the rubber treatment or the RFL adhesive is contained in the adhesion treatment liquid for the second and subsequent baths.

  More specifically, as one aspect of a preferred production method of the present invention, the treatment liquid used in the present invention as described above is a pretreatment liquid having a viscosity of 1 to 5 mPa · s, and further after drying and heat treatment. It is preferable to treat with an adhesion treatment liquid mainly composed of resorcin / formalin / rubber latex (RFL) adhesive. In particular, such an embodiment is optimal for rubber reinforcement applications.

  Furthermore, it is essential here that the pretreatment liquid consists of a crosslinking agent and an emulsifier, and the crosslinking agent used in the pretreatment liquid is a reaction product of a polyhydric alcohol or a polyhydric phenol and chlorine-containing epoxides. It is preferable that

  More specifically, the crosslinking agent preferably used in this pretreatment solution is a reaction product of polyhydric alcohols such as ethylene glycol, glycerol, sorbitol, pentaerythritol, polyethylene glycol and chlorine-containing epoxides such as epichlorohydrin. Examples thereof include reaction products of polyphenols such as resorcin, bis (4-hydroxyphenyl) dimethylmethane, phenol / formaldehyde resin, and resorcin / formaldehyde resin with the chlorine-containing epoxides. Among these, particularly aliphatic polyhydric alcohols such as ethylene glycol, glycerol, sorbitol, pentaerythritol, and polyethylene glycol, and reaction products of these polymers with epichlorohydrin, that is, polyglycidyl ether compounds of polyhydric alcohols are excellent. It is preferable because it exhibits performance.

  Furthermore, the epoxy equivalent of the crosslinking agent used in the pretreatment liquid is preferably 200 g / eq or less, and more preferably in the range of 50 to 200. When the epoxy equivalent is too large, the reactivity of the epoxy in the molecule is low, so that it is difficult to form a sufficient cross-linked structure and the adhesive force tends to be weak. Conversely, when the epoxy equivalent is too small, the reaction between molecules cannot be performed efficiently, and the adhesiveness particularly at high temperatures tends to be lowered. The crosslinking agent preferably has two or more epoxy groups in one molecule.

  Further, the total chlorine content of the crosslinking agent is preferably 10% or more, and more preferably 20% or less. When the total chlorine amount is small, the heat diffusion capacity of the crosslinking agent to the fiber is not sufficient, and as a result, the adhesiveness tends to be lowered. On the other hand, if the amount is too large, the physical properties of the fibers are deteriorated by components generated by thermal decomposition, and not only the adhesiveness but also the physical properties of the structure using the reinforcing fibers tend to be lowered.

  In the pretreatment liquid used in the present invention, an emulsifier is preferably used in combination with the above-mentioned crosslinking agent. As the emulsifier, known emulsifiers such as sodium alkylbenzenesulfonate, dioctylsulfosuccinate sodium salt, nonylphenol ethylene oxide Additives can be mentioned. What is necessary is just to emulsify or disperse | distribute what melt | dissolved said crosslinking agent as it is or as needed in a small amount of solvent as a pre-processing liquid using an emulsifier.

The adhesion treatment liquid preferably used together with the pretreatment liquid is preferably composed of an RFL (resorcin / formalin / rubber latex) adhesive and a crosslinking catalyst.
Here, as the RFL adhesive, those conventionally used for reinforcing rubber fibers are used. Preferably, the molar ratio of resorcin to formaldehyde is in the range of 1: 0.8 to 1: 5. Some are preferable, 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 reduced and the molecular weight is reduced, so that the cohesive force of the adhesive layer may be reduced, and the adhesiveness may be reduced. If too much formaldehyde is added, the resorcin / formalin condensate becomes hard due to an increase in crosslink density, and the compatibility between the RFL and the rubber is inhibited during co-vulcanization with the adherend rubber, resulting in a decrease in adhesion and after treatment. There is a tendency that the fibers of the present invention are remarkably hard and the strength and fatigue properties are lowered.

  The optimum blending ratio of resorcin / formalin and rubber latex in this RFL adhesive varies depending on the addition ratio of the crosslinking catalyst described later, but resorcin / formalin: rubber latex (RFL) is 1: 3 in the solid content ratio. Those in the range of ˜1: 16 are preferable, and those in the range of 1: 4 to 1:10 are particularly preferable. If the ratio of rubber latex is too small, the treated fiber tends to be hard and fatigue resistance tends to decrease, and co-vulcanization with the rubber that is the adherend becomes insufficient, which may reduce adhesion. is there. On the other hand, if the ratio of the rubber latex in the adhesive is too large, sufficient strength as an adhesive film cannot be obtained, so that the adhesive force and the rubber adhesion rate tend to decrease. In addition, the tackiness of the adhesion-treated fibers tends to increase, which tends to cause dirt in the dipping process and dirt in the final product manufacturing process.

  The adhesion treatment liquid preferably used in the present invention preferably contains a crosslinking catalyst together with the above-mentioned RFL adhesive. Examples of such a crosslinking catalyst include amines, ethylene urea, blocked polyisocyanate compounds, and the like, and blocked polyisocyanate compounds are particularly preferable from the viewpoint of stability of the treatment liquid over time and load on the environment.

  The addition ratio of the crosslinking catalyst in the second bath adhesion treatment liquid is within the range of 0.5 to 40% by weight with respect to the total amount of the RFL (resorcin / formalin / rubber latex) adhesive, particularly 10 to 30% by weight. Those in the range of% are preferably used. If the amount added is too small, not only can the crosslinking reaction of the crosslinking agent in the pretreatment solution for the first bath not be caused, but it will tend to be difficult to sufficiently increase the cohesive energy of the RFL adhesive. On the other hand, if the added amount is too large, the compatibility of the adhesive with the rubber to be worn is reduced, the adhesive strength between the rubber and the treated fiber is lowered, and the fiber after the treatment is remarkably hardened, resulting in strength and fatigue. Tends to decrease.

  The solution to be treated as the second bath adhesion treatment liquid preferably used has a total solid content concentration of preferably 1 to 30% by weight, more preferably 10 to 25% by weight. Can be used. When the total solid concentration of the solution of the adhesive treatment agent is lower than the above range, the surface tension of the adhesive solution increases, the uniform adhesion to the fiber surface decreases, and the solid content adhesion decreases. In contrast, if the total solid content concentration is higher than the above range, the viscosity of the treatment liquid becomes high, so that the amount of solid content increases too much, and the dipping treatment process and product production In addition to causing soiling in the process, the treated fibers tend to be hard and fatigue resistance tends to be reduced.

  In order to further adhere the adhesion treatment liquid to the fibers after the pretreatment, means such as contact with a roller, application by spraying from a nozzle, or immersion in a solution can be employed. Moreover, the range of 0.1-10 weight% of the solid content adhesion amount with respect to a fiber is preferable, More preferably, it exists in the range of 1.0-5.0 weight%. In order to control the amount of solids adhering to the fiber, it can be done by means of squeezing with a pressure roller, scraping with a scrubber, etc., blowing off with air blowing, suction, means of beater, and the amount of adhesion increases. For this purpose, it may be attached a plurality of times.

  Furthermore, as the heat treatment conditions after adhesion treatment liquid adhesion, after processing the fiber using the second adhesion treatment liquid, drying and heat treatment in a temperature range of 50 ° C. or higher and 10 ° C. lower than the melting point of the synthetic fiber. To do. More preferably, the temperature range is 220 to 270 ° C., the treatment time is 0.5 to 5 minutes, and further preferably the drying and heat treatment is 1 to 3 minutes. If the 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 synthetic fiber melts and melts, resulting in a decrease in fiber strength. There is.

  As described above, when a two-bath treatment using the pretreatment liquid and the adhesion treatment liquid is performed as a preferred embodiment of the present invention, crosslinking is not performed in the adhesion stage of the pretreatment liquid or in the heat treatment process immediately thereafter. . In other words, it is not agglomerated only by the agent used in the pretreatment liquid, and is crosslinked by the presence of the crosslinking catalyst contained in the adhesion treatment liquid of the second bath, effectively improving the adhesive strength of the reinforcing fiber finally obtained. It can be increased.

  The present invention will be further described in the following examples, but the scope of the present invention is not limited by these examples. Various characteristics were measured by the following methods.

(1) Initial and heat-resistant 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 go straight, and at a temperature of 150 ° C. for 30 minutes, a pressing pressure of 50 kg / cm ² (initial value) or at a temperature of 180 ° C. for 40 minutes, a pressing pressure of 50 kg / cm ² (heat resistance). Value), and then cut into strips along the cord direction. The force required to peel off the prepared sheet from the sheet along the strip in the direction of 90 degrees with respect to the rubber sheet surface at a speed of 200 mm / min is indicated by N / 2.54 cm (1 inch). is there.

(2) High-temperature peel adhesive strength Except that the strip-shaped sample prepared for the above initial peel adhesive strength measurement is changed to an atmosphere of 150 ° C. (high temperature), measurement is performed under the same measurement conditions as above, and high-temperature peel Adhesive strength was assumed.

[Example 1]
A sorbitol-based polyepoxide compound (EX614B manufactured by Nagase ChemteX Corporation) having an epoxy equivalent of 173 g / eq, a 100% viscosity of 5000 mPa · s, and a total chlorine content of 10.1%, and an epoxy equivalent of 144 g Glycerol-based polyepoxide compound (EX314 manufactured by Nagase ChemteX Corporation), 100% viscosity of 170 mPa · s and total chlorine content of 11.5%, sodium 2-ethyl-hexylsulfosuccinate Were mixed at a ratio of 60% by weight, 25% by weight, and 15% by weight, respectively, to obtain a blended liquid having a total solid content of 5% by weight (treatment liquid (1)). The viscosity of this treatment liquid was 1.3 mPa · s.

  In addition, an initial condensate having a resorcin / formalin (R / F) molar ratio of 1 / 0.6 and a solid content concentration of 65% by weight is dissolved under alkaline conditions to obtain a 9% by weight aqueous solution. To this, 99 parts by weight and 104 parts by weight of 41% vinylpyridine / styrene / butadiene terpolymer latex (Pyratex manufactured by Nippon A & L Co., Ltd.) and water are added to 57 parts by weight of the 9% resorcin / formalin aqueous solution, respectively. To this solution was added 3 parts by weight of formalin and 30 parts by weight of a 33% by weight acetoxime blocked diphenylmethane diisocyanate dispersion (DM 6011 manufactured by Meisei Chemical Industry Co., Ltd.), and aged for 48 hours. An agent was obtained (adhesion treatment liquid).

  A multi-filament yarn of 1670 dtex / 384 filament made of polyethylene terephthalate with an intrinsic viscosity of 0.95 is used. The multi-filament yarn is subjected to a lower twist at 40 T / 10 cm, and two of these are twisted together to give an upper twist at 40 T / cm. And a synthetic fiber cord of 3340 dtex / 768 filament was obtained.

  After immersing the cord in the treatment liquid (1) using a contributor processing machine (CA Ritzler Co., Ltd., tire cord processing machine), the cord was allowed to stay at room temperature of 25 ° C. for 2 minutes, and then 240 ° C. A heat treatment was performed at a temperature of 1 minute, followed by immersion in an adhesion treatment solution, followed by drying at a temperature of 170 ° C. for 2 minutes, followed by a heat treatment at a temperature of 240 ° C. for 1 minute. In addition, the fiber passed the process of FIG. In the obtained tire cords, 1.5% by weight of the treatment liquid (1) and 3.7% by weight of the adhesion treatment liquid were observed as solid contents of each treatment liquid. The obtained treated cord was embedded in an unvulcanized rubber compounded with a carcass containing natural rubber as a main component, and after vulcanization, various peel adhesive strengths were evaluated by the above methods. The results are shown in Table 1.

[Example 2]
Adhesion treatment was performed in the same manner as in Example 1 except that the residence time after immersion in the treatment liquid (1) of Example 1 was changed from 2 minutes to 0.5 minutes, and various peel adhesive strengths were evaluated. The results are also shown in Table 1.

[Example 3]
Adhesion treatment was performed in the same manner as in Example 1 except that the residence time after immersion in the treatment liquid (1) of Example 1 was changed from 2 minutes to 4 minutes, and various peel adhesive strengths were evaluated. The results are also shown in Table 1.

[Example 4]
In place of the treatment liquid (1) of Example 1, a sorbitol-based polyepoxide compound (EX614B manufactured by Nagase ChemteX Corporation), a glycerol-based polyepoxide compound (EX314 manufactured by Nagase ChemteX Corporation), sodium 2-ethyl-hexylsulfosuccinate The blending ratio of 35 wt%, 35 wt%, and 30 wt% in the solid content was changed and mixed to obtain a blended solution with a total solid content of 5 wt% (treatment liquid (2)). Adhesion treatment was performed in the same manner as in Example 1 except that this treatment liquid (2) was used.
In the obtained tire cords, 1.7% by weight of the pretreatment liquid (2) and 3.4% by weight of the adhesion treatment liquid were observed as solid content of each treatment liquid. The obtained treated cord was evaluated for various peel adhesive forces in the same manner as in Example 1. The results are also shown in Table 1.

[Example 5]
In place of the polyethylene terephthalate fiber of Example 1, the same adhesion treatment as in Example 1 was performed except that polyethylene naphthalate fiber was used.
That is, as the fiber, a 1670 dtex / 384 filament multifilament yarn made of polyethylene naphthalate having an intrinsic viscosity of 0.76 is used, and the multifilament yarn is twisted at 35 T / 10 cm. A synthetic fiber cord of 3340 dtex / 768 filament was obtained by twisting at / cm.
The obtained tire cord showed 1.5% by weight of the treatment liquid (1) and 3.8% by weight of the adhesion treatment liquid as solid content of each treatment liquid. The obtained treated cord was evaluated for various peel adhesive forces in the same manner as in Example 1. The results of the high temperature and heat resistant peel adhesion are shown in Table 1.

[Comparative Example 1]
Adhesion treatment was performed in the same manner as in Example 1 except that the residence time after immersion in the treatment liquid (1) of Example 1 was changed from 2 minutes to none (0 minute), and various peel adhesive strengths were evaluated. The results are also shown in Table 1.

  The reinforcing fiber obtained by such a method for manufacturing a reinforcing fiber of the present invention has few defects and is excellent in adhesion performance and is generally used for a fiber polymer composite for general purposes. It is particularly suitable for synthetic fibers for rubber reinforcement such as tires, hoses, and belts.

A: One bath dip bath B: Non-heated part C: Heating zone

Claims (8)

  A method for producing a reinforcing fiber in which a fiber is immersed in a treatment liquid, wherein the fiber is a fiber composed of multifilaments, and the treatment liquid is attached to the fiber for 30 seconds or more in an unheated state at 50 ° C. or less. A method for producing a reinforcing fiber, which is held and then dried and heat-treated.   The method for producing a reinforcing fiber according to claim 1, wherein the direction of the fiber is changed by a roll during the holding in the unheated state.   The method for producing a reinforcing fiber according to claim 1 or 2, wherein the fiber is a twisted cord.   The method for producing a reinforcing fiber according to any one of claims 1 to 3, wherein the fiber is a polyester fiber.   The treatment liquid is a pretreatment liquid having a viscosity of 1 to 5 mPa · s, and is further treated with an adhesion treatment liquid mainly comprising a resorcin / formalin / rubber latex (RFL) adhesive after drying and heat treatment. The manufacturing method of the fiber for reinforcement of any one of -4.   The method for producing a reinforcing fiber according to claim 5, wherein the pretreatment liquid comprises only a crosslinking agent and an emulsifier, and the adhesion treatment liquid contains a crosslinking catalyst.   The method for producing a reinforcing fiber according to claim 5, wherein the crosslinking agent is a reaction product of a polyhydric alcohol or polyhydric phenol and a chlorine-containing epoxide.   The method for producing a reinforcing fiber according to any one of claims 5 to 7, wherein the crosslinking catalyst is a block polyisocyanate.

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