JP3090185B2 - Rubber / cord composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber / cord composite made of organic fibers such as polyester fibers, which has excellent adhesiveness and is suitable for use in industrial rubber products such as automobile tires, conveyor belts and hoses. About the body.

[0002]

2. Description of the Related Art Organic fibers such as polyester fibers have high tensile strength and elastic modulus, are excellent in dimensional stability and heat resistance, and are lighter than steel. Therefore, they have attracted attention as rubber reinforcing materials such as tire cords. I have. However, there has been a problem that organic fibers such as polyester fibers have 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 rubber latex (RF) conventionally used as an adhesive with rubber has been used.
L) or a method of treating with a mixed solution of a polyepoxide compound, vinylpyridine latex and a blocked isocyanate compound and then treating with RFL as proposed in JP-A-54-82492. However, the adhesive strength was not yet sufficient. In the future, when organic fibers such as polyester fibers are used as tire cords in the development of lightweight tires that comply with the US fuel efficiency regulation CAFE, it is expected that the adhesiveness will become increasingly important, and organic fibers such as polyester fibers will be used. There is a further need for improved adhesion between fibers and rubber.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the problem of adhesion between rubber and organic fibers such as polyester fibers in the prior art, and integrates the organic fibers with unvulcanized rubber. It is an object of the present invention to provide a rubber / cord composite in which the adhesion between rubber and organic fibers such as polyester fibers is improved, while retaining many features of the organic fibers by vulcanization and vulcanization.

[0004]

According to the present invention, an organic fiber is treated with (a) an epoxy compound and (b) a styrene-butadiene ratio of 5/95 to 45/55 (weight ratio).
Butadiene copolymer rubber latex and (c) formula (1):

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 that releases an isocyanate group by heat treatment, and Z represents at least 1 X represents an active hydrogen residue of a compound having at least one active hydrogen atom and at least one anion-forming group, and X represents an ethyl group of bisphenol A having two hydroxyl groups and having an average molecular weight of 5,000 or less.
Active hydrogen residue of an oxide adduct , wherein n is 2 to 4
And p + m is an integer of 2 to 4 (m ≧ 0.25)
The heat-reactive water-soluble polyurethane resin represented by the following formula (1) is obtained by adding 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 blended at a ratio of (c) / (b) ≦ 2, and then a second treatment liquid comprising a resorcinol-formalin condensate and rubber latex And then vulcanized integrally with the unvulcanized rubber to provide a rubber / cord composite.

[0005]

According to the present invention, an organic fiber such as a polyester fiber first comprises an epoxy compound, a specific styrene-butadiene rubber (SBR) latex and a heat-reactive water-soluble polyurethane resin of the formula (1). 1
It is treated with a treatment liquid and then with a second treatment liquid (RFL treatment liquid) comprising a resorcinol-formalin condensate and rubber latex.

A typical example of the organic fiber used in the present invention is a polyester fiber such as polyethylene terephthalate. Any polyester fiber which has been conventionally used for reinforcing rubber or whose use is considered is considered. A commercially available product, such as Tetoron manufactured by Toray Industries, Inc., is known. Examples of the organic fiber other than the polyester fiber include polyethylene naphthalate and aramid fiber.

The first processing liquid used in the present invention is:
It comprises (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 such 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. .

The first processing solution of the present invention is distributed as a third component.
The heat-reactive water-soluble polyurethane resin to be combined has the formula (1)
X is ethylene of bisphenol A having two hydroxyl groups
Active hydrogen residue of the oxide adduct.

[0011] If the amount of the heat-reactive water-soluble polyurethane resin compounded in the first treatment liquid of the present invention is too small, the adhesive strength may be reduced. Conversely, if the amount is too large, the cord becomes hard and the fatigue resistance is reduced. 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 used to improve the permeability to the cord. Sodium) and the like. The method of treating the polyester fiber or the like with the first treatment liquid can be the same as the method of treating a general fiber, such as by applying a dipping roll into the liquid or spraying. 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 or the like treated with the first treatment liquid according to the present invention is then converted into a second treatment liquid (RFL treatment liquid) which has been widely used as an adhesive between fiber and rubber.
Is processed. The second treatment liquid may be one commonly used in the past, and typically, 30 to 40 resorcin / formalin / rubber latex (for example, styrene / butadiene latex / vinylpyridine / styrene / butadiene-polymer latex). (60% emulsion) = 1/2 to 1/10 (weight ratio), and in addition to these components, an aqueous dispersion of blocked isocyanate can be added as 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 polyester fiber or the like is preferably 2 to 6% by weight. The temperature of the treated polyester fiber is, for example, 80 to 150.
C. and heat-treated at a temperature of, for example, 200 to 250.degree.

[0015] Polyester fibers and the like treated with the first treatment liquid and the second treatment liquid according to the present invention can be used for general-purpose unvulcanized rubber (eg, natural rubber, SBR rubber, polyisoprene rubber, polybutadiene rubber). Compounding agents (for example, vulcanizing agents, vulcanization accelerators, carbon black, antioxidants,
(A filler or the like) is integrally vulcanized with a rubber compound containing the compound according to a conventional method to obtain a rubber / cord composite.

According to the present invention, polyester fibers and the like are 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 treated with an RFL treatment liquid. In this case, the adhesiveness to rubber becomes excellent, and the durability of a rubber product in which polyester fiber or the like is composited is significantly increased.

[0017]

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

[Preparation 1] An unvulcanized rubber was obtained by compounding the following compounding contents (parts by weight) as an unvulcanized rubber compound using a conventional compounding technique. Component weight part {} Natural rubber 100 Zinc white 5 Stearic acid 2 Carbon black 50 Antioxidant 1 Aromatic oil 7 Sulfur 2.25 Vulcanization accelerator 1

[Preparation 2] Production of heat-reactive water-soluble polyurethane resin A Polymethylene polyphenyl polyisocyanate (NCO
100 parts and 31.2 parts of a 4 mol ethylene oxide adduct of bisphenol A at 85 ° C. for 30 parts.
After reacting for 1 minute, a urethane prepolymer of 18.7% of free isocyanate was obtained. Next, 65 parts of dioxane, 50 parts of ε-caprolactam and 0.2 part of triethylamine were added, and the mixture was reacted at a temperature of 75 ° C. for 120 minutes to obtain a polymethylene polyphenyl polyisocyanate and bisphenol A ethylene oxide 4 mol adduct. A partially blocked prepolymer of 5.5% of free isocyanate relative to the total was obtained. Next, 84 parts of a 30% aqueous solution of taurine soda was added at a system temperature of 40 ° C, and reacted at 40 to 45 ° C for 30 minutes. Thereafter, water dilution and dioxane removal were performed so as to have a solid content of 30% to obtain a heat-reactive water-soluble polyurethane resin A.

[Preparations 3 to 5] Production of heat-reactive water-soluble polyurethane resins BD The heat-reactive water-soluble polyurethane resins BD were obtained by the same operation as the heat-reactive water-soluble polyurethane resin A.
The raw materials used and production results are shown below. Thermal reaction type water-soluble polyurethane resin No. B CD ─────────────────────────────────── Organic polyisocyanate (parts) 100 100 100 Compound (Note 1) Active hydrogen-containing compound (Note 2) (parts) 46 69 53 (%) of urethane prepolymer 15.9 13.7 14.5 Free isocyanate dioxane (parts) 70 80 75 ε-caprolactam (parts) 43 45 41 Triethylamine (parts) 0.2 0.2 0.2 (%) of partially blocked prepolymer 4.7 3.5 4.2 Free isocyanate (Note 3) 30% aqueous solution of taurine soda (parts) 80.1 69 75 Thermal reaction type water solubility after water dilution (%) 30 30 30 Solid content of polyurethane resin (Note 1) Polymethylene polyphenyl polyisocyanate NCO content 31.5% (Note 2) No . B: polypropylene glycol molecular weight 500 C: Polypropylene glycol molecular weight 750 No. D: Polycaprolactone polyol molecular weight 500 (Note 3) Free isocyanate based on the sum of polymethylene polyphenyl polyisocyanate and active hydrogen-containing compound

[Preparation 6] Method for producing an aqueous dispersion of blocked isocyanate 100 parts of diphenylmethane diisocyanate and 100 parts of ε-caprolactam were added at 85 ° C. in 200 parts of dioxane at 85 ° C.
After reacting for 20 minutes, dioxane was removed to obtain a blocked isocyanate compound. Next, 100 parts of the blocked isocyanate compound, 25 parts of the nonionic surfactant and 292 parts of water were finely dispersed by a wet fine dispersing machine to obtain an aqueous dispersion of blocked isocyanate having a solid content of 30%.

[Examples 1 to 8] Fiber treatment and integrated vulcanization A first treatment liquid having the composition shown in Table 1 was prepared using polyester fibers (Tetron tire cord (1500 denier / 2) commercially available from Toray) as organic fibers. And subjected to drying and heat treatment (drying 100 ° C. × 1 minute, heat treatment 240 ° C. × 1
Minutes). (A) Epoxy compound: glycerol polyglycidyl ether (b) Rubber latex: styrene / butadiene ratio is 23
/ C (weight ratio) SBR latex (c) Urethane resin: heat-reactive water-soluble polyurethane resin A Next, an RFL treatment liquid of 18% solid content of polyester fiber (composition: resorcinol-formalin condensate / Vp latex (vinyl pyridine) Immersion in styrene-butadiene terpolymer latex (weight ratio = 1/5), drying and heat treatment (drying 100 ° C. × 1 minute, heat treatment 240 ° C. ×)
1 minute). Next, the polyester fiber and the unvulcanized rubber compound shown in Preparation 1 were integrally vulcanized (vulcanization conditions: 170 ° C. × 20 minutes).
The test pieces obtained were measured for hot peeling (100 ° C.), water resistant peeling (40 ° C. × 1 week water resistance test), and flexural hardness. The results are shown in Table I.

[0023]

[Table 1]

[Comparative Examples 1 to 6]
Polyester fibers were treated under the same conditions as in the example, except that the composition of the treatment liquid (a) epoxy compound, (b) rubber latex, and (c) urethane resin was changed as shown in Table II. The results are shown in Table II.

[Comparative Example 7] In the above example, the rubber latex (b) of the first treatment liquid was converted from SBR latex to vinylpyridine / styrene / butadiene (15/15/70).
(Weight ratio)) The latex, (c) the urethane resin was changed from the heat-reactive water-soluble polyurethane resin A to the aqueous dispersion of blocked isocyanate obtained in Preparation 6, (a) an epoxy compound, (b) a rubber latex, (C) A polyester fiber was treated under the same conditions as in the example except that the compounding of the urethane resin was as shown in Table II. (1) (a) / [(b) + (c)] = 0.29 (2) (c) / (b) = 0.4 The results are shown in Table II. [Comparative Example 8] A treatment liquid in which the same RFL liquid as in Example 1 and Vika Bond E manufactured by ICI (P-chlorophenol, resorcin and formalin condensate resin) were mixed at a ratio of 1: 0.6 was used as a first treatment liquid. Was. The results are shown in Table II.

[0026]

[Table 2]

As is clear from the results of Tables I and II, the adhesiveness is low when no SBR latex is added in the epoxy compound / SBR latex ratio, and the adhesiveness tends to decrease even when the amount of the SBR latex is too large. In addition, there is a problem in workability. The adhesiveness is low even without adding a heat-reactive water-soluble polyurethane resin. If the amount of the heat-reactive water-soluble polyurethane resin is too large, the yarn becomes hard and the adhesiveness decreases. When an aqueous dispersion of a blocked isocyanate is used as the urethane resin, the water-resistant adhesiveness is particularly reduced due to the influence of the nonionic surfactant.

Example 9 An aramid fiber (Kevlar commercially available from DuPont) was used as the organic fiber in Example 4.
Example 4 except that the composition of the first treatment liquid was as described below.
The aramid fiber was treated under the same conditions as described above. (1) (a) / [(b) + (c)] = 0.29 (2) (c) / (b) = 0.4 (a) Epoxy compound: glycerol polyglycidyl ether (b) Rubber latex: Styrene / butadiene ratio of 10
/ 90-30 / 70 (weight ratio) SBR latex (c) Urethane resin: heat-reactive water-soluble polyurethane resin A The results are shown in FIG. FIG. 1 shows overcured peeling (vulcanization conditions: 170 ° C. for 40 minutes) and a cord obtained by treating a first treatment liquid using an SBR latex obtained by changing the monomer ratio (weight ratio) of styrene / butadiene. Water resistance peeling (water resistance test at 40 ° C. × 1 week) was plotted.

Comparative Example 9 The procedure of the above example was repeated except that the rubber latex (b) of the first treatment liquid was changed as follows.
The aramid fiber was treated under the same conditions as in the example. The results are shown in FIG. (B) Rubber latex: styrene / butadiene ratio is 2.
5 / 97.5 (weight ratio) SBR latex

Comparative Example 10 An aramid fiber was treated under the same conditions as in the above example, except that the rubber latex (b) of the first treatment liquid was changed as follows. The results are shown in FIG. (B) Rubber latex: a styrene / butadiene ratio of 50
/ 50 (weight ratio) SBR latex

Comparative Example 11 Aramid fibers were treated under the same conditions as in the above example except that the rubber latex (b) of the first treatment liquid was changed as follows. The results are shown in FIG. (B) rubber latex: styrene / butadiene ratio is 70
/ 30 (weight ratio) SBR latex

Comparative Example 12 In the above example, the rubber latex (b) of the first treatment liquid was converted from SBR latex to vinylpyridine / styrene / butadiene latex (15
/ 15/70 (weight ratio)), except that the aramid fiber was treated under the same conditions as in the example. The results are shown in FIG.

[ Example 10 and Comparative Examples 13 to 15] An aramid fiber (Kevlar commercially available from DuPont) was used as the organic fiber in Example 4, and (c) a heat-reactive water-soluble polyurethane resin A or B was used as the urethane resin. , C, and D, and aramid fibers were treated under the same conditions as in Example 4 except that they were immersed in a first treatment solution having the following solid content weight ratio. (1) (a) / [(b) + (c)] = 0.29 (2) (c) / (b) = 0.4 The obtained test piece was hot-drawn (100 ° C.) and water-resistant drawn. (Water resistance test at 40 ° C. × 1 week), the bending hardness and the fatigue resistance were evaluated. The results are shown in Table III.

Comparative Example 16 Aramid fiber was prepared under the same conditions as in the above example, except that the (c) urethane resin of the first treatment liquid was changed to the aqueous dispersion of blocked isocyanate obtained in Preparation 6. (Kevlar commercially available from DuPont) was processed. The results are shown in Table III.

[0035]

[Table 3]

[0036]

As is clear from the results of the above Examples and Comparative Examples, by pre-treating polyester fibers and the like with the first treatment liquid and the second treatment liquid in accordance with the present invention, a superior adhesive strength as compared with the prior art is obtained. Can be obtained, and the durability of products using organic fibers such as polyester fibers can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing the peeling force of a rubber / cord composite obtained in Example 9 and Comparative Examples 9 to 12.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 67:00 (72) Inventor Tsutomu Imamiya 2-1 Oiwake, Hiratsuka-shi, Kanagawa Prefecture Yokohama Rubber Co., Ltd. Hiratsuka Works (72) Inventor Kazuma Nakakita 2-1 Oiwake, Hiratsuka-shi, Kanagawa Prefecture Yokohama Rubber Co., Ltd. Hiratsuka Works (72) Inventor Takayuki Fukutomi 2-1 Oiwake, Hiratsuka-shi, Kanagawa Prefecture Yokohama Rubber Co., Ltd. Hiratsuka Works (72) Inventor Kazuo Sato Shiga 17-45 Kinoshita-cho, Otsu City, Prefecture (72) Inventor Ryuichi Yoshidome 45, Kishijo-in, Ishihara-minami-cho, Minami-ku, Kyoto, Kyoto (72) Inventor Takeshi Fujiwara Takenodai, Nagaokakyo-shi, Kyoto 2 (56) References JP-A 7-179621 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 5/12 C08J 5/06 D06M 15/564 D06M 15/693 C08L 1/00-101/16

Claims (4)

(57) [Claims] 1. An organic fiber comprising: (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 at least one active hydrogen atom and at least one anion-forming group, and X represents an ethyl group of bisphenol A having two hydroxyl groups and having an average molecular weight of 5,000 or less.
Active hydrogen residue of an oxide adduct , wherein n is 2 to 4
And p + m is an integer of 2 to 4 (m ≧ 0.25)
The heat-reactive water-soluble polyurethane resin represented by the following formula (1) is obtained by adding 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 blended at a ratio of (c) / (b) ≦ 2, and then a second treatment liquid comprising a resorcinol-formalin condensate and rubber latex And vulcanized integrally with unvulcanized rubber. 2. The method according to claim 1, wherein the organic fibers are polyester fibers.
Item 7. A rubber / cord composite according to Item 1. 3. The amount of the first treatment liquid attached to the organic fibers is 3 to 3.
3. The rubber / cord duplex according to claim 1, which is 8% by weight.
Coalescing. 4. The adhesion amount of the second treatment liquid to the organic fibers is 2 to 4.
The resin according to any one of claims 1 to 3, which is 6% by weight.
System / code complex.