JP2008031576A - Polyester fiber cord for reinforcing rubber and cap ply member of tire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester fiber cord for reinforcing rubber improved with heat resistant bonding property of the polyester fiber with the rubber in the case of being exposed to a high temperature, that could not be achieved by conventional technologies, also improved with heat resistant strength-holding property and especially suitable for a cap ply cord of a radial tire, and a method for producing the same. <P>SOLUTION: This polyester fiber cord for reinforcing the rubber obtained by imparting an adhesive containing resorcinol-formalin-rubber latex (RFL) and a chlorine-modified resorcinol (P) on the polyester fiber attached with a polyepoxide compound in advance is characterized in that the rubber latex of the adhesive component contains (A) styrene-butadiene-ethylenic unsaturated acid monomer copolymerization latex and (B) styrene-butadiene-vinylpyridine-ethylenic unsaturated acid monomer copolymerization latex. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber fiber-reinforced polyester fiber cord used for tires, hoses and belts. More specifically, a rubber fiber reinforced polyester fiber cord with significantly improved heat-resistant adhesion and heat-resistant strength retention when exposed to a high temperature in rubber during a rubber vulcanization process or product use, The present invention relates to a polyester fiber cord for rubber reinforcement suitable for a cap ply cord of a radial tire.

  Since polyester fiber has excellent strength, elastic modulus and thermal dimensional stability, it has been widely used as a reinforcing material for rubber products such as tires, hoses and belts. When the polyester fiber is used as a reinforcing material embedded in a rubber product, the polyester fiber is thermally deteriorated in a high temperature environment. The chemical thermal degradation is affected by the rubber itself and various additives compounded in the rubber. The rubber contains a vulcanization accelerator such as thiuram, sulfenamide, or guanidine, and an amine anti-aging agent. Polyester fibers that have been subjected to high-temperature treatment in the rubber are mainly used for these. The amine is decomposed or hydrolyzed by amine compounds, low molecular weight compounds generated by oxidative degradation of the rubber itself, water molecules, water contained in the rubber, and the like. Such amine-decomposed or hydrolyzed polyester fibers have a problem in that the initial properties such as adhesion and strength are remarkably deteriorated and cannot be used.

  When the polyester fiber is decomposed by amine or hydrolyzed, the strength is reduced due to the molecular chain breakage and the adhesiveness between the rubber and the fiber layer is lowered. However, when polyester fiber is used as a rubber reinforcing fiber, it has such drawbacks, but it has high strength, high elastic modulus, excellent thermal dimensional stability, improved fatigue resistance and adhesion, and tire manufacturing. Coupled with technological improvements, in recent years it has been used as the carcass material for most passenger car radial tires. However, since it has the above-mentioned essential drawbacks, the heat generated during high-speed running of tires is hard to be trapped and chemically deteriorated, and it is currently used only for carcass materials for passenger cars with relatively small tire sizes. is there. Only a small portion of large tires such as trucks and buses are used. Generally, polyester fiber cords are not used for trucks, bus tires, aircraft tires, large passenger car tires, racing car tires, and the like.

  Moreover, in recent years, high-performance tires suitable for high-speed driving have been increasingly demanded, and radial tires developed to meet these demands are designed to securely expand the tire due to centrifugal force during high-speed driving and compression when touched from the top of the steel belt. Cap ply cords have been used to suppress this. Since the cap ply cord generates heat and becomes higher in temperature than the carcass portion, nylon 66 fibers that cannot withstand use with conventional polyester cords and have excellent adhesion at high temperatures are used.

  However, since a high elastic modulus is preferable as a characteristic of the cap ply cord, a polyester fiber is preferable as a fiber material, and the polyester fiber is also cheap in price. Therefore, a polyester fiber cord that can be used for a cap ply has been developed. It was strongly requested. In order to achieve this, first of all, a great improvement in heat-resistant adhesiveness and an improvement in heat-resistant and strong retention are required.

  Patent Documents 1 to 4 are disclosed as techniques for improving heat-resistant adhesion of polyester fibers.

  In Patent Document 1, a linear aromatic polyester pretreated with a polyepoxide compound is treated with a first treating agent containing a polyepoxide compound and N-methoxymethyl nylon, and then an ethylene urea compound is added to resorcin / formalin latex. A method for treating polyester fiber treated with a second treating agent comprising a cresol novolac type epoxy compound is disclosed.

  Patent Document 2 discloses a formulation in which polyester fibers are treated with a resorcin / formalin latex and a treatment liquid containing a reaction product of a resorcin sulfide compound, a parachlorophenol compound, and a formaldehyde resin.

  Patent Document 3 is a one-step process combining (A) a treatment liquid containing a carrier, (B) a blocked isocyanate aqueous solution, (C) a dispersion of an epoxy compound, and (D) a resorcin-formaldehyde-latex mixed liquid. Alternatively, a technique for treating a polyester fiber material by multistage treatment of two or more stages is disclosed.

  Patent Document 4 discloses an adhesive composition comprising a latex containing vinylpyridine-styrene-butadiene terpolymer particles having a predetermined gel / sol weight ratio and a thermosetting resin.

Although the above-mentioned patent literature techniques are not sufficient, although improvement in heat-resistant adhesion and heat-resistant strength retention at high temperatures is recognized as compared with conventional polyester fiber bonding methods. In particular, it was not at a level that could be put into practical use as a cap ply cord for a radial tire that is the object of the present invention.
Japanese Patent Laid-Open No. 62-21875 JP-A-6-341062 JP 2006-2327 A JP-A-9-78045

  The object of the present invention is to improve the heat-resistant adhesion between the polyester fiber and the rubber when exposed to a high temperature, and to improve the heat-resistant and strong-holding property, which cannot be achieved by the above-described conventional technology. An object of the present invention is to provide a polyester fiber cord for reinforcing rubber particularly suitable for a cap ply cord of a radial tire and a method for producing the same.

  The present invention employs the following means in order to solve such problems. That is, the present invention is a polyester fiber cord for reinforcing rubber obtained by adding a treatment agent containing resorcin / formalin / rubber latex (RFL) and chloro-modified resorcin (P) to a polyester fiber previously provided with a polyepoxide compound. The RFL rubber latex is a styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) and a styrene-butadiene-vinylpyridine-ethylenically unsaturated acid monomer copolymer latex (B). It is a polyester fiber cord for rubber reinforcement characterized by including.

In the polyester fiber cord for reinforcing a hose of the present invention, the following (1) to (3) are preferable conditions, and further excellent effects can be expected by applying these conditions.
(1) The mixing ratio of the styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) and the styrene-butadiene-vinylpyridine-ethylenically unsaturated carboxylic acid monomer copolymer latex (B) is (A) / (B) = 80/20 to 20/80 (dry weight ratio).
(2) The glass transition point (Tg) of the styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) is -20 ° C to 35 ° C.
(3) The amount of the treatment agent containing the resorcin / formalin / rubber latex (RFL) and the chloro-modified resorcin (P) is 3.0 to 8% with respect to 100% by weight of the polyester fiber to which the polyepoxide compound is previously applied. 0% by weight.

  According to the polyester fiber cord for reinforcing rubber of the present invention, the heat-resistant adhesiveness and heat-resistant strength retention when exposed to a high temperature for a long time in rubber during the rubber vulcanization process or product use are remarkably improved. A rubber product reinforced with a polyester fiber cord according to the present invention can withstand severe use for a long period of time when used as a tire, belt and hose. In particular, it is suitable as a cap ply cord for a radial tire that could not be applied with a conventional polyester fiber cord.

  The polyester fiber used in the present invention is composed of a polyester composed of a dicarboxylic acid and a glycol component, and polyethylene terephthalate composed of terephthalic acid and ethylene glycol is particularly preferred.

The polyester fiber cord for rubber reinforcement of the present invention has excellent mechanical properties such as high strength, high toughness, high elastic modulus, low shrinkage and high fatigue resistance, and is exposed to a high temperature in rubber for a long time. In addition, the polyester fiber used in the present invention preferably has the following characteristics because it has excellent chemical durability such as hydrolysis resistance and amine decomposition resistance.
(1) Intrinsic viscosity (IV) = 0.7 to 1.2, more preferably 0.8 to 1.1
(2) Carboxyl end group (COOH) = 10-30 eq / t, more preferably 12-25 eq / t
(3) Copolymerization amount of diethylene glycol (DEG) 0.5 to 1.5% by weight, preferably 0.5 to 1.2% by weight
(4) Strength (T) = 6.0-10.0 cN / dtex, more preferably 7.0-9.0 cN / dtex
(5) Elongation (E) = 8-20%, more preferably 10-16%
(6) Intermediate elongation (ME) = 4.0-6.5%, more preferably 4.5-6.0%
(7) Dry heat shrinkage (ΔS _{150 ° C.} ) = 2.0 to 12.0%, more preferably 3.0 to 10.0%

  In addition, said measurement is performed by the method shown below.

(1) Intrinsic viscosity (IV)
A polymer sample is dissolved in 98% sulfuric acid at a concentration of 1% by weight, measured at 25 ° C. using an Ostwald viscometer, and determined according to the following formula.
Sulfuric acid relative viscosity (ηr) = (sample solution dropping time) / (sulfuric acid solution dropping time)
Two measurements are taken for each sample, and the average value is adopted.

(2) Amount of carboxyl end groups (COOH) A precisely weighed sample (1 g) was immersed in 20 ml of o-cresol (5% water), dissolved at 145 ° C. for 10 minutes, and titrated with a 0.02 N KOH methanol solution. Was determined by At this time, an oligomer such as lactide, which is a cyclic dimer of lactic acid, is hydrolyzed to generate a carboxyl group terminal, so that all of the carboxyl group terminal of the polymer, the monomer-derived carboxyl group terminal, and the oligomer-derived carboxyl group terminal are totaled. The carboxyl group terminal concentration obtained is obtained.

(4) Strength (T), (5) Elongation (E), (6) Intermediate elongation (ME)
The sample is measured with “TENSILON” UCT-100 manufactured by Orientec Co., Ltd. under the constant speed extension conditions shown in the JIS L1013 8.5.1 standard time test. At this time, the holding interval is 25 cm, the pulling speed is 30 cm / min, and the number of tests is 10 times. The elongation at break is determined from the elongation at the point showing the maximum strength in the SS curve. The intermediate elongation is 4.05 cN / dtex (4.5 g / d).

(7) Dry heat shrinkage (ΔS _{150 ° C.} ): The raw yarn is sampled into a husk shape and adjusted in a temperature / humidity adjustment room at 20 ° C. and 65% RH for 24 hours or more. To measure the length L0. Next, the sample was heat-treated in an oven at 150 ° C. for 30 minutes in an unstrained state, and then air-dried in the temperature and humidity control chamber for 4 hours. A load corresponding to 1 cN / dex was again applied to the sample to obtain a length L1. Measure. The 180 ° C. dry heat shrinkage rate was determined from the respective lengths L0 and L1 by the following formula.
150 ° C. dry heat shrinkage = [(L0−L1) / L0] × 100 (%)

  In order for the polyester fiber used for the polyester fiber cord for rubber reinforcement of the present invention to have chemical durability, it is advantageous that the viscosity is high, the carboxyl end groups are small, and the diethylene glycol is small.

  The polyester fiber used in the present invention is not limited by the fineness, the number of filaments, the cross-sectional shape, etc., but usually 200 to 5000 dtex, 30 to 1000 filament, circular cross section yarn is used, 250 to 3000 dtex, 50 to 500 filament. A circular cross-section yarn is preferred. Moreover, as a measuring method of fineness, according to JIS L1013 8.3.1 positive amount fineness a) As a predetermined load, it is good to measure by 5 mN / texx display tex number.

  Further, the polyester fiber used in the present invention may be modified with a terminal carboxyl group blocking agent such as a carbodiimide compound, an epoxy compound, an isocyanate compound, and an oxazoline compound in order to reduce the carboxy terminal group.

  In addition, the polyester fiber of the present invention has been previously provided with a polyepoxide compound. Examples of the polyepoxide compound that can be used in the present invention include compounds containing 0.1 g equivalent or more per 100 g of the compound in at least two epoxy groups in one molecule. Specifically, reaction products of polyhydric alcohols such as pentaerythritol, ethylene glycol, polyethylene glycol, propylene glycol, glycerol, sorbitol and halogen-containing epoxides such as epichlorohydrin, unsaturated by peroxide or hydrogen peroxide, etc. Polyepoxide compound obtained by oxidizing compound, ie, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylene carboxylate, bis (3,4-epoxy-6-methyl-cyclohexylmethyl) adipate, phenol novolak type , Hydroquinone type, biphenyl type, bisphenol S type, brominated novolak type, xylene modified novolak type, phenol glyoxal type, trisoxyphenylmethane type, trisphenol PA type, biphenyl Aromatic polyepoxides such as phenolic polyepoxides, and the like. Particularly preferred are polyepoxides of sorbitol glycidyl ether type or cresol novolac type.

  These compounds are usually used as an emulsified liquid, but in order to make an emulsified liquid or solution, a known emulsifier such as a compound obtained by dissolving the compound as it is or in a small amount of a solvent as necessary, for example, It is emulsified or dissolved using sodium alkylbenzene sulfonate, dioctyl sulfosuccinate sodium salt, nonylphenol ethylene oxide adduct and the like.

  The polyepoxide compound is applied together with a spinning oil agent in a process for producing a polyester fiber. The adhesion amount of the polyepoxide compound at this time is in the range of 0.1 to 5% by weight, with the total amount of polyester fiber and polyepoxide compound being 100% by weight. When the adhesion amount of the polyepoxide compound is less than 0.1% by weight, the effect of the polyepoxide compound is not sufficiently exerted, and there is a possibility that satisfactory adhesion between the polyester fiber and the rubber cannot be obtained. On the other hand, when the adhesion amount of the polyepoxide compound exceeds 5% by weight, the fiber becomes very hard and not only difficult to impart in the yarn making process, but also the permeability of the treatment agent to be treated in the subsequent process is lowered. As a result, the adhesive performance deteriorates, which is not preferable.

  The polyester fiber cord for reinforcing rubber according to the present invention is obtained by twisting the polyester fiber pre-applied with the polyepoxide compound into a raw cord, and weaving the raw cord as it is, or after weaving the raw cord, and then treating with an adhesive. The raw cords used for ordinary carcass tire cords are twisted in the S or Z direction, then two or three twisted cords are combined and the same number of twists are applied in the opposite direction to the twisted cord. It is what. Next, the raw cord is used as a warp, and the weft is covered with cotton yarn or the polyester fiber is covered with cotton yarn to obtain a weft, which is woven in a raw fabric. Next, the ginger fabric is treated with an adhesive to obtain a dip fabric.

  On the other hand, in the case of hoses, belts, and cap ply cords, apply the lower twist, keep the lower twist cord, or, as before, combine two or three of the same number of upper twists in the direction opposite to the lower twist. Spiral cords are formed, and the dip cords are formed by the adhesive treatment in the form of the cords.

  The polyester fiber cord for reinforcing rubber to which the adhesive of the present invention is applied refers to both the dip anti-dip and the dip cord.

  The rubber fiber-reinforced polyester fiber cord of the present invention is provided with an adhesive containing resorcin / formalin / rubber latex (RFL) and chloro-modified resorcin (P).

  Here, the resorcin / formalin / rubber latex is a mixture of an initial condensate of resorcin / formaldehyde and a rubber latex. The resorcin / formaldehyde initial condensate is obtained by condensing resorcin and formaldehyde in the presence of an alkali catalyst or an acid catalyst, and the molar ratio (R / F) of resorcin (R) to formaldehyde (F) is 1. It is preferably /0.3 to 1/5, and more preferably in the range of 1 / 0.75 to 1/2. When R / F is out of the range of 1 / 0.3 to 1/5, the adhesiveness may be lowered or the process passability may be deteriorated. Further, the ratio of the initial condensate of resorcin and formaldehyde and the rubber latex (L) is preferably RF / L = 1/3 to 1/15 in terms of solid content, more preferably 1/5 to 1 /. 10 is good. When the RF / L ratio is out of the range of 1/3 to 1/15, the adhesiveness may be lowered or the process passability may be deteriorated.

  Furthermore, as the resorcin / formaldehyde initial condensate, a novolak type resin obtained by reacting dihydroxybenzene and formaldehyde in advance in the absence of a catalyst or an acidic catalyst can also be used. Specifically, for example, a compound condensed with 0.7 mol or less of formaldehyde with respect to 1 mol of resorcin (for example, trade name “SUMIKANOL 700” registered trademark, manufactured by Sumitomo Chemical Co., Ltd.). When using the novolak-type condensate of resorcin and formaldehyde, it is possible to adjust the molar ratio of resorcin and formaldehyde to 1 / 0.3 to 1/5 by adding formaldehyde after dissolving in an alkaline catalyst aqueous dispersion. preferable.

  The rubber latex used in the present invention includes a styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) and a styrene-butadiene-vinylpyridine-ethylenically unsaturated acid monomer copolymer latex (B). It is necessary to include. Even if one of them is missing, the adhesion to rubber and the heat resistant adhesion may be lowered. Furthermore, both (A) and (B) must be modified with an ethylenically unsaturated acid.

  Examples of the ethylenically unsaturated acid used herein include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, and butenetricarboxylic acid, itaconic acid monoethyl ester, Monoalkyl ester of unsaturated dicarboxylic acid such as monobutyl ester of fumaric acid, maleic acid monobutyl ester, unsaturated sulfonic acid such as sulfoethyl sodium acrylate, sulfopropyl sodium methacrylate, acrylamide propane sulfonic acid or its alkali salt These can be used, and these can be used alone or in combination of two or more.

  In addition, you may introduce | transduce into a rubber latex by hydrolyzing a carboxyl group after copolymerizing an ethylenically unsaturated ester monomer or an ethylenically unsaturated acid anhydride monomer. In this case, the ethylenically unsaturated acid ester monomer and the ethylenically unsaturated acid anhydride monomer include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, butenetricarboxylic acid. Illustrative are mono-, di- and triesters of unsaturated carboxylic acids such as acids, maleic anhydride and the like, and one or more of these are used.

  The mixing ratio of the styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) and the styrene-butadiene-vinylpyridine-ethylenically unsaturated acid monomer copolymer latex (B) is a solid content weight ratio. 80/20 to 20/80 is preferable, and more preferably 25/75 to 50/50. If the styrene-butadiene latex (A) is in the above range or more, the adhesiveness may be lowered, and the styrene-butadiene-vinylpyridine latex (B) is in the above range or the process passability. May get worse.

  The styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) preferably has a glass transition point (Tg) of −20 ° C. to 35 ° C., more preferably −10 ° C. to 30 ° C. ° C. If it is less than -20 ° C, the adhesive strength with rubber may be insufficient, and if it exceeds 35 ° C, the cord may be hard and the bending fatigue resistance may deteriorate.

  The rubber latex used in the RFL contains the above (A) and (B) as essential components, and other rubber latex can be mixed as necessary. Examples include natural rubber latex, butadiene rubber latex, nitrile rubber latex, hydrogenated nitrile rubber latex, chloroprene rubber latex, chlorosulfonated rubber latex, ethylene / propylene / diene rubber latex, etc., and these may be used alone or in combination. Can be used.

  The chloro-modified resorcin (P) used in the present invention is a compound obtained by condensing parachlorophenol, formalin, and resorcin, and is a phenol compound represented by the following general formula.

However, the W is CH ₂ or Sn, in the formula, X, Y represents Cl, Br, I, H, a group selected from alkyl groups of OH and _C 1 -C _6, m is from 1 to 15 It is an integer. The phenol compound represented by the general formula is an initial condensate of a halogenated phenol compound and formaldehyde, an initial condensate of sulfur-modified resorcin and formaldehyde, or an initial condensate of sulfur-modified resorcin and formaldehyde.

  The method for preparing these chloro-modified resorcins is not particularly limited, and examples thereof include parachlorophenol, orthochlorophenol, parabromophenol, paraiodophenol, orthocresol, paracresol, para-tertiary butylphenol and 2,5-dimethylphenol. Of these, parachlorophenol, parabromophenol, paracresol, and paratertiary butylphenol are used, and parachlorophenol is particularly preferably used.

  By condensing such a starting material with formaldehyde in the presence of an alkali catalyst, or by reacting a condensate obtained by previously reacting the starting material in the presence of an acid catalyst with formaldehyde in the presence of an alkali catalyst. A phenolic compound can be obtained.

  Specific examples of the chloro-modified resorcinol include 2,6-bis (2 ′, 4′-dihydroxy-phenylmethyl) -4-chlorophenol (“Kasabond” manufactured by Thomas One Co., Ltd., “Nagase Kasei Kogyo Co., Ltd.” Among them, those mainly composed of a chlorophenol compound having 3 or more benzene nuclei are preferably used from the viewpoint of adhesion and processability.

  The compounding ratio of the chloro-modified resorcinol (P) represented by the general formula (I) and resorcin / formalin / rubber latex (RFL) is P / RFL = 1/1 to 1/5 in terms of solids weight ratio. It is preferable that P / RFL = 1/2 to 1/4. When P / RFL> 1/1, the cord may be hard, and when P / RFL <1/5, the adhesiveness may decrease.

  Moreover, the adhesive of the polyester fiber cord for rubber reinforcement of the present invention can contain a blocked polyisocyanate compound and / or an ethyleneimine compound from the viewpoint of further improving the adhesiveness.

  Examples of the blocked polyisocyanate compound and / or ethyleneimine compound that can be used in the present invention include polyisocyanate compounds such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and triphenylmethane triisocyanate, and phenol and cresol. And reaction products with phenols such as resorcin, lactams such as ε-caprolactam and valerolactam, oximes such as acetoxime, methyl ethyl ketone oxime and cyclohexane oxime, and blocking agents such as ethyleneimine. Among these compounds, aromatic polyisocyanate compounds blocked with ε-caprolactam and aromatic ethylene urea compounds such as diphenylmethane diethylene urea can be preferably used.

  The total solid content of the adhesive containing resorcin / formalin / rubber latex (RFL) and chloro-modified resorcin (P) is preferably 5 to 20% by weight, more preferably 7 to 15% by weight. preferable. Within such a range, the treatment agent is excellent in stability, and an adhesive containing resorcin / formalin / rubber latex (RFL) and chloro-modified resorcin (P) can be uniformly applied to the polyester fiber.

  In order to attach an adhesive containing resorcin / formalin / rubber latex (RFL) and chloro-modified resorcin (P) to the polyester fiber, any method such as dipping, nozzle spraying, and application by a roller can be employed.

  The amount of the adhesive containing resorcin / formalin / rubber latex (RFL) and chloro-modified resorcin (P) with respect to 100% by weight of the polyester fiber pre-applied with the polyepoxide compound is 3.0 to 8.0% in terms of dry weight. %, Particularly in the range of 4.0 to 7.0% by weight. By setting the content in this range, the adhesion to rubber and the process passability are improved.

  The heat treatment after applying an adhesive containing resorcin / formalin / rubber latex (RFL) and chloro-modified resorcin (P) to the polyester fiber is carried out at 80 to 180 ° C. for 0.5 to 5 minutes, more preferably 1 to 3 It is good to heat-treat at a temperature of 150 to 260 ° C., more preferably 220 to 250 ° C. for 0.5 to 5 minutes, more preferably 1 to 3 minutes. If the heat treatment temperature is too low, adhesion to the adherend rubber will be insufficient. On the other hand, if the heat treatment temperature is too high, the polyester fibers will melt, fuse, become hard, and cause a strong deterioration. No longer served.

Further, the polyester fiber cord is a twisted yarn cord subjected to a lower twist and an upper twist, and the lower twist coefficient K ₁ is preferably 400 ≦ K ₁ ≦ 2000, more preferably 500 ≦ K _1. ≦ 1900, more preferably 600 ≦ K ₁ ≦ 1800. If the lower twisting coefficient is out of the preferred range, the adhesive strength after high temperature exposure may be reduced, and the fatigue resistance in rubber may be deteriorated. The upper twist coefficient K ₂ is preferably 800 ≦ K ₂ ≦ 3000, more preferably 900 ≦ K ₂ ≦ 2800, and still more preferably 1000 ≦ K ₂ ≦ 2600. If the upper twist coefficient is outside the preferred range, the adhesive strength after high temperature exposure may be reduced, and the fatigue resistance in rubber may be deteriorated.

The twist coefficient K is determined by K = T × D ^1/2 , (T: number of twists per unit length (times / 10 cm), D: display denier), and the display denier D is JIS L1013 8. 3.1 Positive Fineness a) According to the A method, the predetermined load may be 5 mN / tex × display tex number.

  The polyester fiber cord of the present invention characterized by the above is remarkably improved in heat-resistant adhesion and heat-resistant strength retention when exposed to a high temperature for a long time during a rubber vulcanization process or in use of a rubber product. A rubber product reinforced with a polyester fiber cord according to the present invention can withstand severe use for a long period of time when used as a tire, belt and hose. In particular, it is suitable as a cap ply cord for a radial tire that could not be applied with a conventional polyester fiber cord.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the present invention, the methods for measuring and evaluating the physical properties of the polyester fiber cord for rubber reinforcement are as follows.

(1) Cord strength Measured according to JIS L-1017 (2002) 8.5 using “Tensilon”.

(2) T-initial adhesive strength and T-heat resistant adhesive strength This indicates the adhesive strength between the treatment cord and rubber. In accordance with JIS L-1017 (2002) 3.1, Adhesive strength-A method, the treatment cord is embedded in unvulcanized rubber, the initial adhesive strength under pressure is 150 ° C. for 30 minutes, and the heat resistant adhesive strength is 170 ° C. Press vulcanization was performed for 70 minutes, and after standing to cool, the cord was drawn from the rubber block at a speed of 300 mm / min, and the load required for the drawing was displayed in N / cm.

(3) Heat resistance in rubber This shows the strength retention after vulcanization in rubber. After the cord is stretched in rubber at 170 ° C for 3 hours or after 6 hours, the cord is taken out from the rubber and the tensile strength at breakage is determined at a speed of 300 mm / min. Was shown at 100 minutes.

(4) Glass transition point (Tg)
It measured using the differential scanning calorimeter apparatus (DSC-50: Shimadzu Corporation make). 10 mg of latex dried at room temperature in advance was sealed in a predetermined aluminum pan, heated from -50 ° C. to 100 ° C. at a rate of 5 ° C./min, and the glass transition point of each latex was measured.

In addition, the composition of the rubber compound used for the measurement of T-adhesion force is as follows.
Natural rubber (RSS # 1) 80 (parts by weight)
SBR (JSR1501) 20 (parts by weight)
SRF carbon black 50 (parts by weight)
Stearic acid 2 (parts by weight)
Sulfur 2 (parts by weight)
Zinc flower 5 (parts by weight)
2,2'-dithiobenzothiazole 2 (parts by weight)
Naphthenic acid process oil 3 (parts by weight).

  The rubber latex used in the present invention is as follows.

(Styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A))
“Nalstar” (registered trademark) SR-100 (manufactured by Nippon A & L Co., Ltd.), solid content concentration 51.0%, Tg 25 ° C.
“Nalstar” (registered trademark) SR-103 (manufactured by Nippon A & L Co., Ltd.), solid content concentration 48.0%, Tg 5 ° C.
“Nalstar” (registered trademark) SR-110 (manufactured by Nippon A & L Co., Ltd.), solid content concentration 47.0%, Tg-27 ° C.
(Styrene-butadiene rubber latex, (A '))
"Nippol" LX110 (manufactured by Nippon Zeon Co., Ltd.), solid content concentration 40.5%, Tg-47 ° C
(Styrene-butadiene-vinylpyridine-ethylenically unsaturated acid monomer copolymer latex (B))
V9625 (manufactured by Nippon A & L Co., Ltd.), solid content concentration 40.5%
(Vinylpyridine-styrene-butadiene rubber latex (B '))
"Nippol" (registered trademark) 2518FS (manufactured by Nippon Zeon Co., Ltd.), solid content 40.5%

(Example 1)
A resorcin / formalin initial condensate: “SUMIKANOL S700” (manufactured by Sumitomo Chemical Co., Ltd., 65% aqueous solution) was added to the aqueous caustic soda solution and sufficiently stirred and dispersed. To this, formalin was added so as to have an R / F ratio of 1/2 (molar ratio), mixed uniformly, and aged at a temperature of 25 ° C. for 4 hours. Next, the latex components (dry weight ratio) shown in Table 1 were mixed with the resorcin / formalin initial condensate dispersion at a solid content ratio (RF / L ratio) of 1/9, and the temperature was 25 ° C. Aged for hours. Furthermore, Denabond E (manufactured by Nagase Kasei Kogyo Co., Ltd., chloro-modified resorcinol compound 20% solution) was added so as to be 3/1 in terms of RFL and solid content ratio (RFL / Denabond), stirred sufficiently, and 25 ° C. For 20 hours. The final treatment solution concentration was 13%.

  On the other hand, in the yarn making process, two multifilaments of polyester fiber (T707M (1100T) manufactured by Toray Industries, Inc.) preliminarily provided with a polyepoxide compound (sorbitol glycidyl ether type) were twisted 47 times / 10 cm, and twisted 47 times An untreated cord was obtained by twisting the yarn with a twist number of / 10 cm.

  The cord was immersed in the treatment agent using a compute treater (CA Ritzler Co., Ltd., tire cord processor), dried at 120 ° C. for 2 minutes, and then heat treated at 240 ° C. for 1 minute. . The cord had 3% by weight of the solid content of the treatment agent. The results are shown in Table 1.

(Examples 2-7, Comparative Examples 2-4, 6, 7)
The same procedure as in Example 1 was conducted except that the latex component in RFL was changed to the values shown in Tables 1 and 2. The results are shown in Tables 1 and 2.

(Comparative Example 1)
In the spinning process, the same procedure as in Example 1 was carried out except that a polyester fiber (Toray Industries, Inc., (T705M (1100T))) to which a polyepoxide compound was not previously applied was used. The results are shown in Table 2.

(Comparative Example 5)
In the spinning process, the same procedure as in Comparative Example 4 was carried out except that a polyester fiber not supplied with a polyepoxide compound in advance (manufactured by Toray Industries, Inc., (T705M (1100T))) was used. The results are shown in Table 2.

  As shown in Tables 1 and 2, in the case of Examples 1 to 7 according to the present invention, it can be seen that the deterioration in rubber can be greatly improved as compared with the conventional polyester fibers for reinforcing rubber (Comparative Examples 1 to 7). .

Claims (5)

  A polyester fiber cord for reinforcing rubber formed by applying an adhesive containing resorcin, formalin, rubber latex (RFL), and chloro-modified resorcin (P) to a polyester fiber pre-applied with a polyepoxide compound, the adhesive component The rubber latex is a styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) and a styrene-butadiene-vinylpyridine-ethylenically unsaturated acid monomer copolymer latex (B). Polyester fiber cord for rubber reinforcement characterized by   The mixing ratio of the styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) and the styrene-butadiene-vinylpyridine-ethylenically unsaturated acid monomer copolymer latex (B) is (A). 2. The polyester fiber cord for reinforcing rubber according to claim 1, wherein / (B) = 80/20 to 20/80 (dry weight ratio).   The rubber according to claim 1 or 2, wherein the styrene-butadiene-ethylenically unsaturated acid monomer copolymer latex (A) has a glass transition point (Tg) of -20 ° C to 35 ° C. Polyester fiber cord for reinforcement.   The adhesion amount of the adhesive containing the resorcin / formalin / rubber latex (RFL) and the chloro-modified resorcin (P) is 3.0 to 8.0% by weight with respect to 100% by weight of the polyester fiber to which the polyepoxide compound is previously applied. The polyester fiber cord for reinforcing rubber according to any one of claims 1 to 3. A tire cap ply member using the rubber-reinforced polyester fiber cord according to claim 1.