JPH1134182A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform reduction in weight of a pneumatic tire with excellent high speed durability by solving problem of adhesive properties of polyester fiber to rubber, and using polyester cord as a tire cover layer. SOLUTION: Polyester fiber is treated with first treatment liquid obtained by mixing epoxy compound (a), styrene-butadiene copolymer rubber latex (b) having styrene/butadiene weight ratio of 5/95 to 45/55 and thermal reaction water soluble polyurethane resin represented by a formula at a component solid content weight ratio of 0.1<=(a)/[(b)+(c)]<=2 and (c)/(b)<=2. Then, a polyester cord treated with second treatment liquid containing resorcin-formalin condensate and rubber latex is disposed at an outside of a belt layer 15 of a tread 13 as a cover layer 16 at an angle of substantially 0 deg. to a circumferential direction of the tire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire using a polyester cord for a tire cover layer and having excellent adhesion, high-speed running durability, and light weight.

[0002]

2. Description of the Related Art As the need for high-speed durability of a pneumatic tire has been increasing, a nylon cover layer substantially at 0 ° to the circumferential direction of the tire is currently used outside the belt layer. , Because the cover material is dealt with more than the number of plies and the number of cords as needed,
A tire that emphasizes high speed has a disadvantage that the weight increases. On the other hand, it has been proposed to use a polyester cord having a higher modulus than nylon. However, in practice, it is practically unusable because the adhesiveness is lower than that of nylon (see, for example, JP-A-59-124407). ).

[0003] Polyester fibers have high tensile strength and elastic modulus, and are excellent in dimensional stability, heat resistance, and the like. However, polyester fibers have a problem of poor adhesion to rubber. For this reason, for example, as a method of bonding polyester fiber (for example, polyethylene terephthalate) and rubber, polyester fiber is treated with an epoxy compound, and then resorcinol-formalin, which is conventionally widely used as an adhesive with rubber, is used.
Methods for treating with rubber latex (RFL)
As disclosed in JP-A-824492, a method of treating with a mixed solution of a polyepoxide compound, vinylpyridine latex, and a blocked isocyanate compound and then treating with a RFL has been proposed, but its adhesive strength is still insufficient. I couldn't say. Especially in the future, fuel efficiency regulations of the United States CA
When polyester fibers are used as tire cords in the development of lightweight tires and the like corresponding to FE, it is certain that the adhesiveness will become increasingly important, and it is necessary to further improve the adhesion between the polyester fibers and rubber.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the problem of the adhesion between polyester fiber and rubber in the prior art, and uses a polyester cord as a tire cover layer to provide a high-speed running durability and a high tire durability. An object of the present invention is to provide a pneumatic tire that can achieve weight reduction.

[0005]

According to the present invention, a pair of left and right bead portions, a pair of left and right side wall portions connected to the bead portion, a tread portion located between the side wall portions, and a pair of left and right bead portions are provided. In the pneumatic tire comprising the carcass layer provided between the bead portions and the belt layer provided on the carcass layer in the tread portion, the polyester fiber is made of (a) an epoxy compound, and (b) a styrene / butadiene ratio of 5 / 95-45 / 55 (weight ratio) styrene
A butadiene copolymer rubber latex and (c) Formula (1) are provided.

[0006]

Embedded image

Wherein A represents an isocyanate residue of an organic polyisocyanate compound having 3 to 5 functional groups, Y represents an active hydrogen residue of a blocking agent compound which releases an isocyanate group by heat treatment, and Z represents , At least one
X represents an active hydrogen residue of a compound having at least one active hydrogen atom and at least one anion-forming group;
Is an active hydrogen residue of a polyol compound having three hydroxyl groups and an average molecular weight of 5,000 or less, n is an integer of 2 to 4, and p + m is an integer of 2 to 4 (m ≧ 0.25). The heat-reactive water-soluble polyurethane resin shown is prepared by mixing the components (a), (b) and (c) in a solid content ratio by weight: (1) 0.1 ≦ (a) / [(b) + (c)] ≦ 2 and (2) treatment with a first treatment liquid formulated in a ratio of (c) / (b) ≦ 2, followed by treatment with a second treatment liquid comprising a resorcinol-formalin condensate and rubber latex A pneumatic tire is provided, wherein the obtained polyester cord is covered with rubber and disposed as a cover layer at an angle of substantially 0 ° with respect to the tire circumferential direction outside the belt layer of the tire tread portion.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the pneumatic tire according to the present invention is not particularly limited, and any conventionally known pneumatic tires, as well as various types of pneumatic tire structures currently under development. What is essential is that the tread portion has the above-described configuration.

An example will be described below with reference to FIG. FIG. 1 is a half sectional view in the meridian direction of a preferred example of the pneumatic tire of the present invention. In FIG. 1, a pneumatic tire A of the present invention has a pair of right and left bead portions 11, 11.
And a pair of left and right side wall portions 12 and 12 connected to the bead portions 11 and 11 and the side wall portion 1
A carcass layer 14 is mounted between a pair of left and right bead portions 11 and 11, and a belt layer is provided around the outer periphery of the tread portion 13 in the tread portion 13. 15 and a cover layer 16 is disposed outside thereof. 10 is a tread surface.

According to the present invention, the polyester fiber constituting the cover layer is firstly an epoxy compound,
Treated with a first processing liquid comprising a specific styrene-butadiene rubber (SBR) latex and a heat-reactive water-soluble polyurethane resin of the above formula (1), and then a second processing liquid comprising a resorcinol-formalin condensate and rubber latex (RFL treatment solution).

A typical example of the polyester fiber used in the present invention is polyethylene terephthalate and the like, but any polyester fiber which has been conventionally used for rubber reinforcement or whose use is considered, Tetoron manufactured by Toray Industries, Inc. is known as a commercially available product.

The first treatment liquid used in the present invention is:
It consists of (a) an epoxy compound, (b) an SBR latex, and (c) a heat-reactive water-soluble polyurethane resin, which must satisfy the following composition (solid content weight ratio). (1) 0.1 ≦ (a) / [(b) + (c)] ≦ 2 and (2) (c) / (b) ≦ 2 Particularly preferred composition is that each solid content is SBR latex 10
20 to 70 parts by weight of the epoxy compound and 10 to 100 parts by weight of the heat-reactive water-soluble polyurethane resin with respect to 0 parts by weight.

The epoxy compound used in the present invention is a known epoxy compound having one or more glycidyl groups in a molecule, preferably a polyol based compound such as glycerol polyglycidyl ether, diglycerol polyglycidyl ether and sorbitol polyglycidyl ether. It is an epoxy compound. If the amount of the epoxy compound in the first treatment liquid is too small, sufficient adhesiveness may not be obtained, while if too large, the stability of the treatment liquid may be reduced, which is not preferable.

The SBR latex used in the first treatment liquid of the present invention has a styrene / butadiene monomer ratio (weight ratio) of 5/95 to 45/55, preferably 10/90 to 45/55.
It is a copolymer rubber latex in the range of 30/70. If the styrene content in the styrene / butadiene weight ratio is too small, processability such as gum up to a roll during dipping may be reduced, and if it is too large, the adhesive strength may be reduced. The SBR latex can be produced by any conventionally known emulsion polymerization method, and preferably has a solid content of 30 to 60% by weight. In addition, if the amount of the SBR latex blended in the first processing liquid is too small, sufficient adhesion may not be obtained. Conversely, if the amount is too large, workability during dip processing may decrease, which is not preferable. .

Examples of the heat-reactive water-soluble polyurethane resin to be added as the third component to the first treatment liquid of the present invention include, for example, polyether polyol having the formula (1) wherein X has 2 to 4 hydroxyl groups. Compounds (eg, bisphenol A
Or an active hydrogen residue of a polyester polyol compound of the formula (1) wherein X has 2 to 4 hydroxyl groups (for example, a polyester polyol compound obtained by ring-opening polymerization of caprolactone). And the like.

If the amount of the heat-reactive water-soluble polyurethane resin mixed in the first treatment liquid of the present invention is too small, the adhesive strength may decrease. On the other hand, if the amount is too large, the cord becomes hard and the fatigue resistance becomes poor. It is not preferable because the property may be lowered.

The first treatment liquid according to the present invention can be prepared by mixing the above-mentioned components by a general method. If necessary, a surfactant (for example, sulfosuccinic acid) may be added to improve the permeability of the cord. Sodium) and the like. The processing method of the polyester fiber or the like with the first processing liquid can be performed by applying a dipping roll into the liquid, spraying spraying, or the like in the same manner as the general fiber processing method. The amount of the first treatment liquid adhering to polyester fibers or the like is preferably 3
８8% by weight. The treated polyester fiber or the like is dried at a temperature of, for example, 80 to 150 ° C., and is further heat-treated at a temperature of, for example, 200 to 250 ° C.

The polyester fiber treated with the first treatment liquid according to the present invention is then treated with a second treatment liquid (RFL treatment liquid) which has been widely used as an adhesive between fiber and rubber. The second processing solution may be one commonly used in the past, and typically has a resorcinol-formalin / rubber latex (e.g., a styrene-butadiene latex / vinylpyridine-styrene-butadiene-polymer latex, etc.). 60% emulsion) =
It is 1/2 to 1/10 (weight ratio), and in addition to these components, a blocked aqueous isocyanate dispersion or the like can be blended if necessary.

The processing method of the second processing liquid according to the present invention can be the same as the conventional method. The amount of adhesion to the polyester fiber is preferably 2 to 6% by weight. The treated polyester fiber or the like is dried at, for example, a temperature of 80 to 150 ° C., and further heat-treated at a temperature of, for example, 200 to 250 ° C.

The polyester fiber treated with the first treatment liquid and the second treatment liquid according to the present invention is a general-purpose unvulcanized rubber (for example, natural rubber, SBR rubber, polyisoprene rubber,
Polybutadiene rubber) is compounded with a general-purpose vulcanizing compounding agent (for example, vulcanizing agent, vulcanization accelerator, carbon black, anti-aging agent, filler, etc.) and vulcanized integrally according to a conventional method. / Can be used in the cover layer as a code composite.

As described above, according to the present invention, the polyester fiber is first treated with a first treatment liquid comprising a specific epoxy compound, a specific styrene-butadiene rubber and a specific heat-reactive water-soluble polyurethane resin, and then the RFL is used. By being treated with the treatment liquid, the adhesiveness to rubber becomes excellent. For example, the polyester cord treated in this way is covered with a rubber cord, and the polyester fiber and rubber (for example, a general-purpose unvulcanized rubber is vulcanized). When the cover layer is used as a composite with a sulfuric acid, a vulcanization accelerator, a carbon black, an antioxidant, a filler, and the like as appropriate, the durability of the tire is significantly increased. In the present invention, the composite is used as a reinforcing layer at a substantially 0 ° angle with respect to the tire circumferential direction.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

The adhesiveness and high-speed durability used in the following examples were evaluated by the following methods. Adhesion evaluation method Cut out a sample from the tire and remove 1 between the belt and cover material.
A peeling test was performed in a 00 ° C. atmosphere, and the degree of rubberization of the cover layer was evaluated with a nylon material being 100. The higher the index, the higher the adhesion.

Tire Test Method Two types of tires were tested as shown in the table below.種類 Tire type 1st tire (185 / 65R14) 2nd tire (225 / 60R16 ) ───────────────────────────────── Air pressure 220kPa 220kPa ───────────── ────────────────────Load 4.45kN 6.31kN ────────────────────── ─────────── Lim 14 × 5J 16 × 61 / 2JJ ───────────────────────────── ──── The test method was as follows:
2 hours at km / h, then 30 minutes at 121 km / h as step 2 and 30 minutes at 129 km / h as step 3; after that, increase the speed by 8 km / h every 30 minutes, and run until failure. . In this way, the running distance up to the failure is represented by an index with the nylon material as 100.

Example 1 and Comparative Examples 1 to 3 As shown in Table I, a first pneumatic tire (185 / 65R) having the same structure except that the organic fibers of the cover material were variously changed.
14) was manufactured, and the adhesion and high-speed durability were evaluated, and the weight of the member was measured. The results are shown in Table I.

[0026]

[Table 1]

The materials of other members of the tire used for manufacturing the used tire are as follows.

Examples 3-4 and Comparative Examples 4-6 A second pneumatic tire (225 / 60R) having the same construction as shown in Table II except that the organic fibers of the cover material were variously changed.
16) was manufactured, and the adhesion and high-speed durability were evaluated as described above, and the weight of the member was measured. The results are shown in Table II.

[0029]

[Table 2]

The other members of the tire used for manufacturing the used tire are as follows.

[0031]

As described above, according to the present invention, the polyester cord can be used for the cover layer by using a specific two-step treatment which can provide a high adhesive strength, and the tire can be lightweight while maintaining high-speed durability. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view in the meridian direction of an example of a pneumatic tire of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Tread surface 11 ... Bead part 12 ... Side wall 13 ... Tread part 14 ... Carcass layer 15 ... Belt layer 16 ... Cover layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 75/04 C08L 75/04

Claims (1)

[Claims] 1. A pair of left and right beads, a pair of left and right sidewalls connected to the beads, a tread located between the sidewalls, and a carcass layer provided between the pair of left and right beads. And a pneumatic tire comprising a belt layer provided on a carcass layer in the tread portion, wherein the polyester fiber comprises: (a) an epoxy compound;
(B) styrene / butadiene ratio of 5/95 to 45/55
(Weight ratio) styrene-butadiene copolymer rubber latex and (c) formula (1): [Wherein, A represents an isocyanate residue of an organic polyisocyanate compound having 3 to 5 functional groups, Y represents an active hydrogen residue of a blocking agent compound that releases an isocyanate group by heat treatment, and Z represents at least 1 X represents an active hydrogen residue of a compound having two active hydrogen atoms and at least one anion-forming group, and X represents an active hydrogen residue of a polyol compound having 2 to 4 hydroxyl groups and having an average molecular weight of 5,000 or less. And n is an integer of 2 to 4, and p + m is an integer of 2 to 4 (m ≧ 0.25)], the components (a), (b) and (C) is blended at a solid content weight ratio of (1) 0.1 ≦ (a) / [(b) + (c)] ≦ 2 and (2) (c) / (b) ≦ 2. First resorcinol solution, and then resorcinol-forma A polyester cord obtained by treating with a second treating solution comprising a rubber condensate and a rubber latex was covered with rubber and disposed as a cover layer outside the belt layer of the tire tread at an angle of approximately 0 ° with respect to the tire circumferential direction. A pneumatic tire, characterized in that: