JPH09111050A - Rubber/code composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber-code composite material capable of improving adhesion of an organic fiber to rubber in addition to retention of the characteristics of the organic fiber by treating the organic fiber with 2 kinds of treating liquid then vulcanizing the organic fiber integrally with green rubber. SOLUTION: At first, organic fiber is treated with a first treating liquid formulated with (A) an epoxy resin, (B) a styrene-butadiene copolymer rubber latex at weight ratio of styrene/butadiene of 5/95-45/55, and (C) a thermally reactive water-soluble polyurethane resin of the formula (A is an organic polyisocyanate residual group bearing 3-5 functional groups; Y is an active hydrogen of an isocyanate-blocking compound; Z is an active hydrogen of a compound bearing both an active hydrogen and an anion-forming group; X is an active hydrogen of a polyol with an average molecular weight of <=5,000 having 2-4 OH groups; (n), (p + m) are each 2-4, m>=0.25). Then, the treated fiber is treated with a second treating liquid comprising a resorcinol- formaldehyde condensed product and a rubber latex, and is integrally vulcanized with green rubber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber / cord composite which uses organic fibers such as polyester fibers as cords and has excellent adhesiveness and is suitable for use in industrial rubber products such as automobile tires, conveyor belts and hoses. Regarding 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. There is. However, there is a problem that organic fibers such as polyester fibers have poor adhesion to rubber. Therefore, for example, as a method for adhering a polyester fiber (for example, polyethylene terephthalate) to rubber, after treating the polyester fiber with an epoxy compound, a resorcinol-formalin rubber latex (RF) which has been widely used as an adhesive with a rubber has been used.
L) and a method of treating with a mixed solution of a polyepoxide compound, a 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. Adhesion is expected to become more and more important 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, and it is expected that the organic properties such as polyester fibers will become more important. There is a further need for improved fiber-rubber adhesion.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention solves the problem of the adhesiveness between the rubber and the organic fiber such as polyester fiber in the above-mentioned prior art, and integrates the organic fiber and the unvulcanized rubber. It is an object of the present invention to provide a rubber / cord composite which has been cured and vulcanized to retain many features of the organic fiber and has improved adhesion between the rubber and the organic fiber such as polyester fiber.

[0004]

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

Embedded image [In the formula, 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 in the molecule. Represents an active hydrogen residue of a compound having 1 active hydrogen atom and at least 1 anion-forming group, and X is an active hydrogen residue of a polyol compound having 2 to 4 hydroxyl groups and having an average molecular weight of 5000 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 heat-reactive water-soluble polyurethane resin represented by the formulas (a), (b) and (C) is a solid content weight ratio of (1) 0.1 ≦ (a) /
[(B) + (c)] ≦ 2 and (2) (c) / (b) ≦
It is treated with the first treatment liquid formulated in the ratio of 2 and then the second treatment consisting of resorcin / formalin and rubber latex.
A rubber / cord composite obtained by integrally vulcanizing with an unvulcanized rubber after being treated with a treatment liquid is provided.

[0005]

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, an organic fiber such as polyester fiber is first composed of 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) consisting of a resorcin-formalin condensate and a rubber latex.

A typical example of the organic fiber used in the present invention is a polyester fiber such as polyethylene terephthalate, which may be any polyester fiber conventionally used for rubber reinforcement or whose use is being studied. As a commercially available product, Tetron manufactured by Toray Industries, Inc. is known. Examples of organic fibers other than polyester fibers include polyethylene naphthalate and aramid fibers.

The first processing liquid used in the present invention is
It consists of (a) epoxy compound, (b) SBR latex and (c) heat-reactive water-soluble polyurethane resin, and these must satisfy the following composition (solid content weight ratio). (1) 0.1 ≦ (a) / [(b) + (c)] ≦ 2 and (2) (c) / (b) ≦ 2 A particularly preferable composition is that each solid content is SBR latex 10.
The epoxy compound is 20 to 70 parts by weight and the heat-reactive water-soluble polyurethane resin is 10 to 100 parts by weight based on 0 part by weight.

The epoxy compound used in the present invention is a known epoxy compound having one or more glycidyl groups in the molecule, preferably a polyol system such as glycerol polyglycidyl ether, diglycerol polyglycidyl ether and sorbitol polyglycidyl ether. It is an epoxy compound. If the blending amount of the epoxy compound in the first treatment liquid is too small, sufficient adhesiveness may not be obtained, and conversely, if it is too large, the stability of the treatment liquid may be decreased, 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.
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, the processability such as gum up to the roll during dip treatment may be deteriorated, and if it is too large, the adhesive strength may be decreased. The SBR latex can be produced by any conventionally known emulsion polymerization method, and the preferred solid content is 30 to 60% by weight. In addition, if the amount of the SBR latex blended in the first treatment liquid is too small, sufficient adhesion may not be obtained, and conversely, if it is too large, the workability during dip treatment may decrease, which is not preferable. .

As an example of the heat-reactive water-soluble polyurethane resin blended as the third component in the first treatment liquid of the present invention, for example, polyether polyol having X of formula (1) having 2 to 4 hydroxyl groups is used. Compounds (eg bisphenol A
Hydrogen oxide residue), or an active hydrogen residue of a polyester polyol compound (for example, a polyester polyol compound obtained by ring-opening polymerization of caprolactone) of formula (1) in which X has 2 to 4 hydroxyl groups. Examples thereof include polyurethane resins.

If the blending amount of the heat-reactive water-soluble polyurethane resin blended in the first treatment liquid of the present invention is too small, the adhesive force may be lowered. On the contrary, if the blending amount is too large, the cord becomes hard and fatigue resistance increases. It is not preferable because there is a risk of deterioration in sex.

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 (eg, sulfosuccinic acid) may be added to improve the permeability of the cord. Sodium) and the like can be added. The method of treating the polyester fiber or the like with the first treatment liquid may be the same as a general fiber treatment method, such as dip roll coating in the liquid or spray spraying. The amount of the first treatment liquid deposited on the polyester fibers 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 then 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 the second treatment liquid (RFL treatment liquid) which has been generally used as an adhesive between fibers and rubber.
Is processed. This second treatment liquid may be one that has been widely used in the past, and is typically 30 to 50% of resorcin / formalin / rubber latex (for example, styrene / butadiene latex / vinylpyridine / styrene / butadiene terpolymer latex). 60% emulsion) = 1/2 to 1/10 (weight ratio), and in addition to these components, a blocked isocyanate aqueous dispersion and the like can be blended as necessary.

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

The polyester fibers treated with the first treatment liquid and the second treatment liquid according to the present invention are used for general-purpose vulcanization of general-purpose unvulcanized rubber (for example, natural rubber, SBR rubber, polyisoprene rubber, polybutadiene rubber). Compounding agents (eg vulcanizing agents, vulcanization accelerators, carbon black, antioxidants,
A rubber / cord composite can be obtained by integrally vulcanizing a rubber compound containing a filler, etc.) according to a conventional method.

According to the present invention, the polyester fiber or the like is first treated with the first treatment liquid consisting of the specific epoxy compound, the specific styrene-butadiene rubber and the specific heat-reactive water-soluble polyurethane resin, and then the RFL processing liquid. By being treated with, the adhesiveness with rubber becomes excellent, and the durability of the rubber product in which polyester fiber or the like is compounded is remarkably enhanced.

[0017]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the following examples.

[Preparation 1] The following unvulcanized rubber compounding ingredients (parts by weight) were compounded using a conventional compounding technique to obtain unvulcanized rubber. Component Weight ───────── ─────── Natural rubber 100 Zinc white 5 Stearic acid 2 Carbon black 50 Anti-aging agent 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
Content 31.5%) 100 parts and ethylene oxide 4 mol adduct of bisphenol A 31.2 parts at 85 ° C. 30
After reacting for 1 minute, a urethane prepolymer having a free isocyanate of 18.7% 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 for 120 minutes at an internal temperature of 75 ° C. to give a polymethylene polyphenyl polyisocyanate and a 4 mol ethylene oxide adduct of bisphenol A. A partially blocked prepolymer with 5.5% free isocyanate based on total was obtained. Next, 84 parts of an aqueous solution of taurine soda having a concentration of 30% was added at a system temperature of 40 ° C., and a reaction was performed at 40 to 45 ° C. for 30 minutes. Then, water was diluted and dioxane was removed so that the solid content became 30%, and a heat-reactive water-soluble polyurethane resin A was obtained.

[Preparation 3-5] Production of heat-reactive water-soluble polyurethane resins B-D By the same operation as the heat-reactive water-soluble polyurethane resin A, heat-reactive water-soluble polyurethane resins B-D were obtained.
The raw materials used and the production results are shown below. Heat-reactive water-soluble polyurethane resin No. B C D ─────────────────────────────────── Organic polyisocyanate (part) 100 100 100 100 compounds (Note 1) Active hydrogen-containing compound (Note 2) (part) 46 69 53 (%) of urethane prepolymer 15.9 13.7 14.5 Free isocyanate dioxane (part) 70 80 75 75 ε-caprolactam (part) 43 45 41 Triethylamine (part) 0.2 0.2 0.2 Partially blocked prepolymer (%) 4.7 3.5 4.2 Free isocyanate (Note 3) 30% taurine soda aqueous solution (part) 80.1 69 75 Heat-reactive water-soluble after dilution with water (%) 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 No. C: polypropylene glycol molecular weight 750 No. D: Polycaprolactone polyol Molecular weight 500 (Note 3) Free isocyanate based on the total of polymethylene polyphenyl polyisocyanate and active hydrogen-containing compound

[Preparation 6] Method for producing an aqueous dispersion of a blocked isocyanate: 100 parts of diphenylmethane diisocyanate and 100 parts of ε-caprolactam are added to 200 parts of dioxane at 1 ° C 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 a nonionic surfactant and 292 parts of water were finely dispersed by a wet fine disperser to obtain a blocked isocyanate aqueous dispersion having a solid content of 30%.

Examples 1 to 8 Fiber Treatment and Integrated Vulcanization Polyester fiber (Tetoron tire cord (1500 denier / 2) commercially available from Toray) as the organic fiber was used as the first treatment liquid having the composition shown in Table 1. It was dipped in and dried and heat-treated (drying 100 ° C x 1 minute, heat-treatment 240 ° C x 1
Minutes). (A) Epoxy compound: glycerol polyglycidyl ether (b) Rubber latex: Styrene / butadiene ratio is 23
/ 77 (weight ratio) SBR latex (c) Urethane resin: heat-reactive water-soluble polyurethane resin A Next, polyester fiber is treated with an RFL treatment liquid having a solid content of 18% (composition: resorcin / formalin condensate / Vp latex (vinyl pyridine) -Styrene-butadiene terpolymer latex (weight ratio) = 1/5), dipped, dried and heat-treated (dry 100 ° C x 1 minute, heat-treated 240 ° C x
1 minute). Next, the polyester fiber and the unvulcanized rubber compound shown in Preparation 1 are integrally vulcanized (vulcanization condition 170 ° C. × 20 minutes).
The resulting test pieces were measured for hot peeling (100 ° C.), water resistant peeling (40 ° C. × 1 week water resistance test) and bending hardness. The results are shown in Table I.

[0023]

[Table 1]

[Comparative Examples 1 to 6]
The polyester fiber was treated under the same conditions as in the examples except that the formulations of (a) epoxy compound, (b) rubber latex and (c) urethane resin in the treatment liquid were 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)) Latex, (c) urethane resin was changed from the heat-reactive water-soluble polyurethane resin A to the blocked isocyanate aqueous dispersion obtained in Preparation 6, (a) epoxy compound, (b) rubber latex, (C) Polyester fibers were treated under the same conditions as in Example except that the formulation of the urethane resin was 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 prepared by blending the same RFL liquid as that of Example 1 and VCI Bond E (P-chlorophenol, resorcin and formalin condensate resin) manufactured by ICI in a ratio of 1: 0.6 was used as the first treatment liquid. I was there. The results are shown in Table II.

[0026]

[Table 2]

As is clear from the results of Tables I and II, the adhesiveness was low when the SBR latex was not added in the epoxy compound / SBR latex ratio, and the adhesiveness tended to decrease even if the SBR latex amount was too large. In addition, there is a problem in workability. Adhesiveness is low even without addition of heat-reactive water-soluble polyurethane resin. When the amount of the heat-reactive water-soluble polyurethane resin is too much, the yarn becomes hard and the adhesiveness also deteriorates. Further, when an aqueous dispersion of blocked isocyanate is used as the urethane resin, the water-resistant adhesiveness is particularly lowered due to the influence of the nonionic surfactant.

[Example 9] Aramid fiber (Kevlar commercially available from DuPont) was used as the organic fiber of Example 4,
Example 4 except that the composition of the first treatment liquid was changed as follows:
The aramid fiber was treated under the same conditions as above. (1) (a) / [(b) + (c)] = 0.29 (2) (c) / (b) = 0.4 (a) Epoxy compound: glycerol polyglycidyl ether (b) Rubber latex: Styrene / butadiene ratio is 10
/ 90 to 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 the overcure peeling (vulcanization condition: 170 ° C. × 40 minutes) and the code obtained by treating the first treatment liquid using the SBR latex obtained by changing the styrene / butadiene monomer ratio (weight ratio). Peeling resistance to water (water resistance test at 40 ° C. × 1 week) was plotted.

[Comparative Example 9] In the above-mentioned example, 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 Example 1 except that the rubber latex (b) of the first treatment liquid in the above Example was changed as follows. The results are shown in FIG. (B) Rubber latex: styrene / butadiene ratio of 50
/ 50 (weight ratio) SBR latex

[Comparative Example 11] An aramid fiber was treated under the same conditions as in Example 1 except that the rubber latex (b) of the first treatment liquid was changed as described below. The results are shown in FIG. (B) Rubber latex: styrene / butadiene ratio of 70
/ 30 (weight ratio) SBR latex

[Comparative Example 12] In the above Example, the rubber latex (b) of the first treatment liquid was changed 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 Example. The results are shown in FIG.

[Examples 10 to 13] Aramid fiber (Kevlar commercially available from DuPont) was used as the organic fiber of Example 4, and (c) a heat-reactive water-soluble polyurethane resin A, B, C or D was used as the urethane resin. Was used, and the aramid fiber was treated under the same conditions as in Example 4, except that the aramid fiber was immersed in the first treatment liquid 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.), water-resistant drawn (Water resistance test at 40 ° C. × 1 week), bending hardness and fatigue resistance were evaluated. The results are shown in Table III.

[Comparative Example 13] Aramid fiber was prepared under the same conditions as in Example 1 except that the urethane resin (c) of the first treatment liquid was changed to the blocked isocyanate aqueous dispersion obtained in Preparation 6 in the above example. (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-mentioned Examples and Comparative Examples, by pre-treating the polyester fiber or the like with the first treatment liquid and the second treatment liquid according to the present invention, the adhesive strength superior to that of the conventional one is obtained. It is possible to obtain a rubber / cord composite having, and it is possible to improve the durability of products using organic fibers such as polyester fibers.

[Brief description of the drawings]

FIG. 1 is a diagram showing the peeling force of rubber / cord composites obtained in Example 9 and Comparative Examples 9-12.

[Procedure amendment]

[Submission date] March 29, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

[0026]

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Mr. Imamiya, 2-1, Oiwake, Hiratsuka-shi, Kanagawa Yokohama Rubber Co., Ltd. Hiratsuka Plant (72) Inventor, Kazumasa Nakakita, 2-1-1, Oiwake, Hiratsuka, Kanagawa Stock Company Hiratsuka Factory (72) Inventor Takayuki Fukutomi No. 2 Oiwake, Hiratsuka City, Kanagawa Prefecture Yokohama Rubber Company Hiratsuka Factory (72) Inventor Kazuo Sato 17-45 Kinoshita-cho, Otsu City, Shiga Prefecture (72) Inventor Ryuichi Yoshidome 45 Kichishoin Ishiharaminami-cho, Minami-ku, Kyoto Prefecture (72) Inventor Takeshi Fujiwara 2 Takenodai, Nagaokakyo-shi, Kyoto

Claims (5)

[Claims] 1. An organic fiber comprising (a) an epoxy compound,
(B) Styrene / butadiene ratio is 5/95 to 45/55
(Weight ratio) styrene-butadiene copolymer rubber latex and (c) formula (1): [In the formula, 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 in the molecule. Represents an active hydrogen residue of a compound having 1 active hydrogen atom and at least 1 anion-forming group, and X is an active hydrogen residue of a polyol compound having 2 to 4 hydroxyl groups and having an average molecular weight of 5000 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 heat-reactive water-soluble polyurethane resin represented by the formulas (a), (b) and (C) is blended in a solid content weight ratio of (1) 0.1 ≦ (a) / [(b) + (c)] ≦ 2 and (2) (c) / (b) ≦ 2. Treated with the first treatment liquid, and then resorcinol formali A rubber / cord composite obtained by integrally vulcanizing with an unvulcanized rubber after treatment with a second treatment liquid consisting of a condensation product and a rubber latex. 2. The rubber / cord composite according to claim 1, wherein X in the formula (1) is an active hydrogen residue of a polyether polyol compound having 2 to 4 hydroxyl groups. 3. The polyether polyol compound is an ethylene oxide adduct of bisphenol A. 2.
The rubber / cord composite described in 1. 4. The rubber / cord composite according to claim 1, wherein X in the formula (1) is an active hydrogen residue of a polyester polyol compound having 2 to 4 hydroxyl groups. 5. The rubber / cord composite according to claim 4, wherein the polyester polyol compound is a polyester polyol compound obtained by ring-opening polymerization of caprolactone.