JPS61129304A - Bias tire for compact truck - Google Patents

Abstract

PURPOSE:To improve the performance of a bias tire for a compact track using polyester reinforcing cord by specifically constituting the twist of cord, fiber density, ultimate viscosity, tensile strength of yarn, amorphous absorbing peak temperature and dry contraction coefficient. CONSTITUTION:A cord is constituted from a polyester fiber having a main component of polyethyleneterephthalate and set to 5 times or more per 10cm of twist, 1.397g/cm<2> or less of fiber density and 0.75 or more of ultimate viscosity. Also, it is set to 7.0g/d or more of tensile strength of yarn when said twist is untwisted to two or less times per 10cm, 148-154 deg.C of amorphous absorbing peak temperature on the mechanical tangent-temperature curve measured with 110Hz, 7.0% or less of elongation E under 4.5g/d of load and 6.0% or less of dry contraction coefficient SHD at 150 deg.C for 30min, the relationship between SHD and E falling within the extent specified by formula I. By this constitution is improved tire performance.

Description

[Detailed description of the invention] (Industrial application field) This invention is primarily used for light trucks.

This invention relates to a pneumatic tire with a bias structure using polyester cord as a reinforcing material.

(Prior art) Recently, radial tires with a carcass layer parallel to the tire axis have been increasingly used for passenger cars, buses, and large trucks. Carcass ply made of rubberized cloth usually 4
Bias tires, in which a carcass layer is formed by stacking one or more tires obliquely to each other with respect to the tire axis, are still mainly used. Bias tires are cheaper than radial tires, but they have problems in handling stability, noise, etc. It is well known that using polyester fibers, which have a higher modulus than nylon fibers, as the material for tire cords is effective in solving these problems, but this is still not the case for bias tires on small trucks or larger vehicles. However, nylon fibers are used, and polyester fibers, which are effective in solving the problem, are not used.The reason for this is that polyester fibers have insufficient chemical stability in rubber. In other words, when bias tires are used on large vehicles such as light trucks or larger, the internal temperature of the tire may rise to over 140°C due to the heat generated during driving. depolymerization reaction easily occurs.

This is because the strength of the polyester fiber rapidly decreases.

There are various proposals for improving the chemical stability of polyester fibers in rubber. For example, a method of improving chemical stability by reducing the amount of terminal carboxyl groups of polyester to 15 equivalents/10'g or less (Japanese Patent Publication No. 37-58
No. 21) and a specific method for reducing the amount of terminal carboxyl groups in polyester fibers (see U.S. Patent No. 3).
, No. 975, 329, JP 55-11681.
(see Publication No. 6) have been proposed. however,
The fact that polyester fibers are still hardly used in bias tires for light trucks shows that simply reducing the terminal carboxyl groups does not provide sufficient chemical stability of polyester fibers in tires.

The fact that the chemical stability of the above-mentioned polyester fibers is insufficient can be understood by considering the depolymerization mechanism of polyester. That is, the depolymerization of polyester in rubber is a hydrolysis reaction, and the terminal carboxyl group acts as an acidic catalyst. On the other hand, various amine compounds are added to rubber as vulcanization accelerators and deterioration inhibitors, and these amine additives diffuse into polyester and act as basic catalysts for the hydrolysis of polyester. As a catalyst for the hydrolysis of polyester, basic catalysts have significantly higher activity than acidic catalysts, so simply reducing the terminal cal and hydroxyl groups is not effective in improving the chemical stability in rubber. .

In addition, for the purpose of improving the chemical stability of polyester fibers in rubber, there is a method of reducing the hysteresis loss of polyester fibers and reducing the exothermic property in rubber to lower the temperature of the depolymerization reaction (U.S. Patent No. 4). ,101,52
(see Specification No. 5) has been proposed. Although the method proposed above exhibits a very remarkable effect in the Gutdeyer (Mallory) tube fatigue test, no decrease in the tire internal temperature is observed in actual running of tires using this polyester cord. This means that the ratio of the amount of heat generated by the polyester fibers in the tire to the amount of heat generated by the tire as a whole.

This is thought to be due to the fact that the ratio is significantly lower than the ratio in the Gutsde ear tube fatigue test mentioned above. Therefore, it is not easy to improve the chemical stability of polyester fibers in rubber using methods for reducing the hysteresis loss of polyester fibers.

(Problems to be Solved) Previously, the present inventors invented an adhesive-treated polyester cord for reinforcing rubber with improved chemical stability in rubber (Japanese Patent Application No. 129487/1982). By using the above-mentioned polyester cord, we have obtained a bias tire for light trucks that has excellent low noise and handling stability, and has tire performance comparable to that of a conventional bias tire whose carcass layer is a nylon cord. be.

(Means for solving the problem) In a bias tire for light trucks whose carcass is a plurality of ply layers in which a large number of polyester cords are arranged and treated with adhesive, the polyester cord is a polyester fiber whose main component is polyethylene terephthalate. The polyester fiber is twisted 5 times or more per 10 cm, and the density of the polyester fiber is 1.397 g/an? Below, the intrinsic viscosity is 0.75 or more and the polyester cord is 10
The tensile strength of the polyester yarn when untwisted to 2 twists or less per c+n is 7.0 g/d or more, 110
) The amorphous absorption peak temperature (Tα) cursed by the mechanical tangent (tan δ) and temperature curve measured at 12 is 148 to 154
℃, and the drying shrinkage (SHD) when heat treated at 150℃ for 30 minutes without tension is 6.0% or less, 4.5
The above S
HD is 13.3XE""D・75~20.2E-"・s
This is a bias tire for light trucks characterized by having a tire size in the range of 9.

The polyester fiber is made of polyester containing at least 95 mol% of polyethylene terephthalate units, and its density is 1.397 g/(17 or less), and if the density exceeds the above, the chemical stability in the rubber is significantly reduced. The intrinsic viscosity of polyester fiber (measured at 30°C using a solvent of phenol/tetrachloroethane = 6/4) is 0.
．． The intrinsic viscosity is 75 or more, preferably 0.8 to 1.2, and if the intrinsic viscosity is less than 0.75, the average degree of polymerization will be less than 134 and the fatigue resistance will begin to decrease significantly.

In general, the cord structure and number of twists of rubber reinforcing fibers are changed depending on its use and purpose, so it is difficult to generalize and define its mechanical properties. However, in this invention, adhesive treatment The cords were carefully untwisted to define the mechanical properties in untwisted yarns with no more than 2 twists per lOrM. An example of the stress-strain curve of an untwisted yarn is shown in FIG. Because the untwisted yarn is twisted as a cord and subjected to heat treatment, the untwisted yarn develops a crimp. Therefore, as shown in Figure 1, the stress-strain curve of the crimp part is cursed at the beginning of the stress-strain curve, so the stress-strain curve is curved at the point S where the auxiliary line (dotted line) drawn on the initial modulus part intersects the horizontal axis. It is necessary to take measurements by regarding it as the starting point of the line.

The tensile strength of the above-mentioned untwisted yarn is 7.0 g/d or more, and if it is less than 7.0 g/d, it is necessary to use a large amount of cord as a reinforcing material, resulting in high cost.

In addition, the untwisted yarn has a dry heat shrinkage rate (SI-ID) of 0% or less when heat treated at 150°C for 30 minutes without tension, and an elongation (E) under a load of 4.5 g/d. 7.0%
The range is as follows, and SHD and E have the following relationship.

13.3×E −”−’ ”, 1SHD
≦20.2E −'・”Figure 2 is a graph showing the relationship between E and SHD of the untwisted yarn, and the hatched part is the range of the above formula.

If the SHD exceeds 6.0%, the shape stability of the rubber composite will be impaired. If E exceeds 7.0% and the modulus becomes small, the advantages of polyester over nylon will not be exhibited, and a tire with excellent low noise and handling stability will not be obtained. Further, when SHD and E meet the above relationship, the treated cord has good thermal dimensional stability and at the same time, the chemical stability in rubber is significantly improved. S
When HD is less than 13.3X E-'・75, chemical stability decreases;
``・'' ``Thermal dimensional stability decreases.

Next, the heat treatment temperature in the adhesive treatment process of the polyester yarn and 11OH2 were measured. Mechanical loss tangent (t,
amorphous absorption peak temperature (T
The relationship with a) is shown in Figure 3. As is clear from FIG. 3, the value of Ta depends on the heat treatment temperature (dip temperature). In Figure 3, A is the case of a fiber drawn from ρ○Y (also referred to as highly oriented amorphous fiber or partially oriented yarn), and D is a case of a fiber drawn from an undrawn yarn that is close to normal orientation. There are differences in the microstructures of certain six types of fibers due to differences in their manufacturing methods, and it is not possible to immediately discuss the mobility of amorphous molecular chains between the two samples using Ta alone, but at least the amorphous molecular chains due to heat treatment of the same sample cannot be directly discussed. Regarding motility, Ta can be used as a major factor. It was observed that Ta decreased rapidly when the heat treatment temperature exceeded 220°C, and it was observed that the mobility of amorphous molecular chains and the chemical stability of polyester in rubber showed an extremely good correspondence. . The improvement in the mobility of amorphous molecular chains due to heat treatment is due to the improvement in the degree of crystal perfection (improvement in the degree of completeness of the crystal structure and increase in the crystal size) due to heat treatment. It is thought that this occurs as a result of the accumulation of

In addition, in the case of fibers drawn from POY, Ta is approximately 10°C lower than fibers drawn from undrawn yarns, which are nearly non-oriented, so Ta can be used to determine whether or not the fibers have passed through PO'l'. The Tα of the untwisted yarn of the present invention is from 148°C to 154°C.
Must be between □. When Tα is less than 148°C, chemical stability is reduced, and when Tα exceeds 154°C, thermal dimensional stability is reduced.

Next, a method for manufacturing a cord in a bias tire according to the present invention will be explained. The above-described polyester in which at least 95 mol% of the structural units consists of ethylene terephthalate units and has an intrinsic viscosity of 0.75 or more is extruded from a spinneret in a molten state, and the solidified filament has a birefringence of 0.020 to 0. os.

Cooling is carried out so that it falls within the range of . For this purpose, the filament tension at the solidification point must be 1.5 x 10'dy.
ne/aJ to 7.5X10' dyne/aif, more preferably 2. The filament is cooled and solidified at a take-up rate ranging from OX 10' dyne/cd to s, oxto' dyne/al.

At this time, 1. the use of relatively high-temperature cooling air (50°C to 60°C), which the present inventors had already proposed (Japanese Unexamined Patent Application Publication No. 58-119)
98419) is particularly preferred for the purpose of the present invention.

After winding up the solidified spinning wheel, or immediately without winding it up, it is stretched at a magnification of 2.0 to 3.0 to give 7.5 g/
Gives yarn strength of d or more. The polyester high tenacity yarn thus obtained is essentially a fiber with good thermal dimensional stability. In addition, in order to improve the adhesion of the fiber to rubber, it is used during or after spinning and drawing.

A so-called surface activation treatment may be performed using an epoxy compound having 2@ or more epoxy groups or a compound having incyanate groups.

In order to use the polyester drawn yarn as a reinforcing material for rubber, it is preferably 5 times/10 CI11 or more, that is, a twist coefficient of 150 or more, in order to facilitate handling in subsequent processes and improve the fatigue resistance of the product. is given a twist of 950 or more to create a two-strand, three-strand, etc. cord. Twist coefficient (
TF) is defined by the following equation.

T F = T W X V'■ TW is the number of twists per IOcIm, and D is the yarn denier. Of course, it goes without saying that the number of twists and the cord configuration may be changed as appropriate depending on the use and purpose.

The cord obtained as described above is subjected to a so-called dipping treatment in order to impart adhesiveness to rubber.

The adhesive treatment liquid includes (A) an aqueous dispersion of an epoxy resin, (
B) Aqueous dispersion of blocked isocyanate, (C) A treatment liquid containing a carrier for polyester fibers, and (D) A resorcin formaldehyde resin-rubber latex mixed liquid, etc., in combination or alone, in one or two or more stages of multi-stage treatment. The polyester cord is treated by:

In order to keep the adhesion of the cord to the rubber as high as possible in the above treatment, it is preferable that at least a part of the treatment liquid is an aqueous dispersion of the epoxy resin (A).

Examples of the epoxy resin for the treatment liquid (A) include glycerin and propylene glycol. Ethylene glycol, hexanetriol, sorbitol, trimethylolpropane, 3-methylpentanetriol, polyethylene glycol, polypropylene oil ILl such as D-/Lz
Group J polyhydric alcohols Reaction products with halohydrins such as toehychlorohydrin, resorcinol, catechol,
Hydroquinone.

1.3.5-Trihydroxybenzene, bis(4-hydroxyphenyl)methane, bis(・1-hydroxyphenyl)dimethylmethane, aromatic polyhydric alcohols such as 4.4'-bihydroxyphenyl, and epichlorohydrin. reaction products with halohydrins such as novolak-type phenolic resins, novolak-type cresol resins, novolak-type phenolic resins such as novolak-type zorcin resin, and halohydrins such as epichlorohydrin.

Oxidize unsaturated bonds with peracetic acid such as diglycidyl ether, vinylcyclohexene diepoxide, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexenecarboxylate, etc. Examples include epoxy compounds obtained by

The blocked isocyanane-1 of the treatment liquid (B) is as follows:
Tolylene diisocyanate, bitolylene diisocyanate, dianisidine diisocyanate, 1-ramethylene diisocyanate, hexamethylene diisocyanate,
m-phenylene diisocyanate, m-xylene diisocyanate, alkylbenzene diisocyanate, ■-
Chlorobenzene-2,4-diisocyanate, cyclohexylmethane-diisocyanate, 3,3'-dimethoxydiphenylmethane-4,4'-diisocyanate,
l-nitrobenzene-2,4-diisocyanate, l-
Alkoxybenzene-2,4-diisocyanate, ethylene diisocyanate, propylene diisocyanate,
Cyclohexylene-1,2-diisocyanate, 3,3
'-Dichloro-4,4'-biphenylene diisocyanate, diphenylene diisocyanate.

2-Chlortrimethylene diisocyanate, butylene-
Diisocyanates such as 1,2-diisocyanate, ethylidene diisocyanate, dibuenylmethane-4,4'-diisocyanate, diphenylethane diisocyanate, 5-naphthalene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, diphenylmethane triisocyanate, Butane-1,2,2-
Triisocyanates such as triisocyanate, trimethylolpropane tolylene diisocyanate 3 adduct, and 2,4.4'-diphenyl ether triisocyanate, represented by the general formula (1 = Or 1 + 2 + 3 +
1 or 2 or more polyisocyanate compounds such as polyfunctional isocyanates such as polymethylene polyphenylisocyanate which is a mixture of 1 and 1, phenols such as phenol, thiophenol, cresol, resorcinol, t-butanol, t-pentanol, t-
Tertiary alcohols such as butanethiol, aromatic amines such as diphenylamine, buphenylnaphthylamine, xylidine, ethyleneimines such as ethyleneimine and propyl imine, imides such as succinimide and phthalic imide, acetoacetic ester , acetylacetone.

Active methylene compounds such as malonic acid diester, methylcaptans such as 2-mercaptobenzothiazole and t-dodecylmercaptan, lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam, and urea.

Ureas such as diethylene urea and thiourea; oximes such as acetoxime, cyclohexanone oxime, benzophenone oxime, and methyl ethyl ketone oxime; diaryl compounds such as carbazole, phenol naphthylamine, and N-phenylxylidine; bisulfites; 1 of incyanate blocking agents such as acids, α-pyrrolidone, etc.
It is obtained by reacting one species or two or more species by a known method.

Specific examples of carriers for treatment liquid (C) include benzoic acid, methyl benzoate, propyl benzoate, benzoic acid derivatives such as m-nitrobenzoic acid, salicylic acid, methyl salicylate, phenyl p-bromsalicylate, etc. Salicylic acid derivatives, phthalic acid, phthalic acid derivatives such as ethyl phthalate, acetophenone, propiophenone, p-chlorophenol, P-nitrophenol, 0-phenylphenol, 2,4.6-tribromophenol, m-cresol , phenol derivatives such as resorcinol, aromatic ethers such as anisole and p-bromoanisole, monochlorobenzene, p-dichlorobenzene, 1,3.5
- halogenated benzenes such as trichlorobenzene and p-dibromobenzene, naphthalene derivatives such as methylnaphthalene and α-bromonaphthalene, di- and triphenylmethane derivatives such as diphenyldichloromethane, triphenolchloromethane, and triphenylcarbinol; diphenyl, 4,4'-dioxydiphenyl, 4,4'
-Diphenyl derivatives such as diaminodiphenyl, tricresyl phosphate, allyl-(3-hydroxyphenyl)-
Ether and its polymer, the reaction product of resorcin represented by the general formula (where m and n are 0 or positive integers, the average of 1m is 1, and the average of n is 1), P-chlorophenol, and formaldebide compound, general formula (where m', n' are O or positive integers, X is -CH,
- group, -0- group, or -5x- group).

The treatment liquid (D) is usually called an RFL liquid, and includes an initial condensate obtained by reacting resorcin and formalin under an acid or alkali catalyst, a styrene-butadiene copolymer latex, a carboxyl group-containing styrene-butadiene copolymer latex, It is an aqueous liquid mixed with one or more latexes such as styrene-butadiene-vinylpyridine terpolymer latex, acrylonitrile-butadiene copolymer latex, polychloroprene latex, polybutane diene latex, and natural rubber latex.

According to the study results of the present inventors, when polyester fibers containing polyethylene terephthalate as a main component are used as a rubber composite, adhesion is a major factor that determines the molecular mobility of amorphous molecular chains and, ultimately, the chemical stability in the rubber. This is the heat treatment temperature in the agent treatment (dipping) step. The heat treatment temperature is preferably 220°C or lower, particularly 210°C or lower and 170°C or higher.

The importance of the processing temperature will be explained with reference to FIG.

Figure 4 shows a graph of the polyester treated cord of the present invention in a rubber composite, the composite being heated at 170°C for 3 hours, the treated cord taken out from the rubber composite, the residual strength measured, and the results plotted against the heat treatment temperature. It is. As is clear from Figure 4, heat treatment temperature is a dominant factor in the chemical stability of polyester in rubber. Although the rate of deterioration in rubber varies greatly, in rubber compositions that are practically used for tires, conventional polyester treated cords show a residual strength of 20 to 40% after heating the rubber composite at 170°C for 3 hours. is normal. It will therefore be clear to those skilled in the art that the residual strength of the processing code in the present invention is quite surprising.

Note that the intrinsic viscosity, Tα, density and SH in the present invention
The method for measuring D is as follows.

[Measurement method of intrinsic viscosity]

Measurement was performed at 30°C in a mixed solvent of phenol:tetrachloroethane=3:2.

[Measurement method of temperature distribution of mechanical loss tangent] Sample length 4 using Toyo Baldwin Rheopybron DDV■
C11, Mechanical loss tangent (t, an δ) was measured while heating in air at a heating rate of 1'C/min, and when the temperature distribution was determined, the temperature of the amorphous absorption peak that appeared was Tα. .

[Method for measuring the heat shrinkage rate SHD of untwisted yarn at 150°C] To remove the crimp that appears after untwisting, the heat shrinkage sample length (Ω) was measured under a load of 0.5 g/d, and the load was Except 1
The sample was allowed to freely shrink for 30 minutes in an air bath at 50°C, and then the length (Q') of the sample after heat shrinkage was measured under a load of 0.5 g/d, and the heat shrinkage rate was determined using the following formula.

[Method of measuring density]

30℃ using carbon tetrachloride-〇hebutane density gradient tube
It was measured with

In order to manufacture bias tires for light trucks using the polyester cord obtained as described above, both sides of the polyester-treated cord, which has been dip-treated in the form of a blind weave, are coated with rubber using a calender roll in a conventional manner. Bias-cut the tires at different widths and angles, and mold the tread rubber, side rubber, beads, etc. together into green tires, which are then subjected to vulcanization using a vulcanizer and post-cure inflation (PCI) to become tire products. The present invention provides a bias tire for light trucks.

Fi, OO-13 specified in JIS-D4202
-4Pf+ to 8.25-16-14Pl'l.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 1.0, a diethylene glycol content of 1.0 mol%, and a carboxyl group content of 10 equivalents/LO"H was melt-spun and drawn under the conditions shown in Table 1 below. Spun yarn average birefringence As is clear from A
B is a comparative example in which so-called POY is drawn, and B is a comparative example in which a normal undrawn yarn (almost unoriented amorphous) is drawn.

The number of twists of each of the 100 OD drawn yarns thus obtained was 4.
9x49 (twist/10 rx, twist coefficient 1549) double yarn cord, made of epoxy resin (trade name Epon 812), which is a reaction product of glycerin and epichlorohydrin.
, manufactured by The Dow Chemical Company), was added 0.2% of didodecyl sulfocinate sodium salt as an emulsifier to a 2% by weight aqueous dispersion of
% by weight to form a first treatment solution, 5.7 parts by weight of resorcin, 6.3 parts by weight of 37% formalin aqueous solution, 3 parts by weight of 10% caustic soda aqueous solution and 5.7 parts by weight of water were added in a polymerization section at 30°C for 16 hours. After aging, an RFL solution containing 175.7 parts by weight of Nirapol 2518FS (trade name, butadiene-styrene-vinylpyridine copolymer latex manufactured by Nippon Zeon Co., Ltd.) and 23.6 parts by weight of water was added as a second treatment solution. It was processed under the conditions shown in -2. The physical properties of the treated cord, the fiber properties after untwisting, and the retention of tilting force after deterioration in 170°C rubber are also shown in Table 2.

(Blank below) Table 1 Table 2 As is clear from Table 2 above, cord A of the present invention has the same strength as the cord of the comparative example, but It has low shrinkage and excellent chemical stability in rubber.

Bias tires of 7.50-16 (14PR) were manufactured using 6 plies of each of the above treatment codes 1 and 2 and the conventional nylon treatment coat (12 (iod/2)) as a carcass layer, and the tires were subjected to drum tests and actual vehicle tests. The index of each performance is shown in Table 3.The index is based on the performance using the conventional nylon treated cord as 100.

Note that two plies of nylon treated cord (s4od/2) were used for the breaker layer of each of the above tires.

Table 3 In Table 3, noise level is 10 for noise called road noise.
The sound pressure level of 0H2-300112 is measured, and the smaller the index, the smaller the noise. Driving stability is a sensory test using an actual vehicle. High speed and durability are atII constant values according to FMVSS Ho2O3 by drum test, the former being the maximum speed at which the tire breaks, and the latter being the mileage at which the tire breaks.

Cornering power is the force with respect to changes in tire slip angle based on drum tests.

(Effects of the invention) As shown in Table °-3, tires with a carcass layer made of polyester cord 1゜2 produce less noise and have better handling stability than tires with a carcass layer made of nylon cord. There is. However, tires using conventional polyester cord 2 have high speed performance.

Although the durability is poor and it is not practical, tires using the polyester cord 13 of the present invention have the same high speed as conventional tires using the 1 nylon cord.

It is durable and, as mentioned above, has low noise.

Excellent handling stability.

[Brief explanation of drawings]

FIG. 1 is a graph of the stress-strain curve of an untwisted yarn. Figure 2 is a graph showing the relationship between the intermediate elongation of untwisted yarn and the heat shrinkage rate (SHD) at 150°C. Figure 3 is a graph showing the relationship between the intermediate elongation of untwisted yarn and the heat shrinkage rate (SHD) at 150°C. Figure 3 is a graph showing the relationship between the mechanical loss tangent (+
, ,]nδ) is a graph showing the relationship between the temperature distribution of the amorphous absorption peak temperature (Tα), and Figure 4 shows the relationship between the dip heat treatment temperature and the remaining strength of the polyester cord degraded in rubber at 170°C for 3 hours. It is a graph showing the relationship between Patent Applicant Toyobo Pet Coat Co., Ltd. Agent Patent Attorney Takeshi Sakano Misspoken words 1) Tsukasa Ryo 1 to 1 Figure 2 E (〃) Figure 3 Figure 4 Zuran i! ! ! I! Yuno (0C) → Go 1 Bill ゛ 9 [l 7F 1 Display of the case 1982 Patent Order No. 250784 2 Name of the invention Bias tire for small trucks 3 Person making the amendment Relationship to the case Patent applicant location Address: 2-2-8 Dojimahama, Kita-ku, Osaka Name: Toyobo Betcode Co., Ltd. 4 Agent Residence: 2-10-6 Azuchi-cho, Higashi-ku, Osaka Countermeasures for amendment Claims column 7 of the specification Contents (1) The claims on page 1, line 5 to page 2, line 2 of the specification have been corrected as shown in the attached sheet. (2) Page 6, line 6 of the specification [1 “Tire performance” has been corrected to “Tomo”. (3) “Drying shrinkage rate” on page 6, line 6, line 2 of the specification has been changed to “Dry shrinkage rate” (4) "Chlortrimethylene diisocyanate" on page 16, line 14 of the specification is corrected to "chlortrimethylene diisocyanate 1-". (5) Lines 4-3 from the bottom of page 16 of the specification. "Buphenylnaphthylamine" is corrected to "2 phenylnaphthylamine". (6) "Polychloroprene latex" on page 19 of the specification, lines 19-20 is corrected to "polychloroprene latex". (7) Page 20 of the specification At the end of the 4th line, ``Polyester fiber'' is ``Polyester fiber''.
To J;iT d:. (8) Specification IIF, page 20, line 1 (9) Second line from the bottom of page 16, bottom-1 of the specification, “Yarn intrinsic viscosity (%) J is corrected to [yarn ultimate viscosity.” Range [1] A small 1-rack bias tire with a carcass made of multiple ply layers arranged with a large number of polyester cords and treated with an adhesive, in which the polyester cords are made of polyester fibers whose main component is polyethylene terephthalate, and locm More than 5 twists per piece are given,
The density of the polyester fiber is 1.397 g/d or less,
The intrinsic viscosity is 0.75 or more, and the tensile strength of the polyester yarn is 7.0 g/d or more when the polyester cord is untwisted to 2 twists or less per LO cm, 110)+
The amorphous absorption peak temperature (Tα) appearing on the mechanical tangent (syan δ)-temperature curve measured in 2 is 148 to 154°C, and the dry shrinkage rate when heat treated under tension at 150°C for 30 minutes. (SHr)) is 6.0% or less, 4.5g
/dThe elongation under load (E) is 7.0% or less, and the above SM
C: 13.3xI” ~2o, 2E “”
+MHI! A bias tire for light trucks featuring a 1-near pitch.

Claims (1)

[Scope of Claims] [1] A bias tire for light trucks having a carcass made of a plurality of ply layers arranged with a large number of polyester cords and treated with an adhesive, wherein the polyester cords are made of polyester fibers containing polyethylene terephthalate as a main component. 5 or more twists per 10 cm, the density of the polyester fiber is 1.397 g/cm^3 or less, the intrinsic viscosity is 0.75 or more, and the polyester cord is twisted 2 times or less per 10 cm. The tensile strength of the polyester yarn when twisted is 7.0 g/d or more, 110
The amorphous absorption peak temperature (Tα) appearing in the mechanical tangent (tanδ)-temperature curve measured at HZ is 148 to 154°C
and has a drying shrinkage rate (SHD) of 6.0% or less when heat treated at 150°C for 30 minutes without tension, 4.5g
/dThe elongation under load (E) is 7.0% or less, and the above SH
D is 13.3 x E^-^0^. ^7^5~20.2E^
-＾0＾． A bias tire for small trucks that is characterized by having a diameter in the range of ^8^8.