JPH075870B2 - Adhesive composition of rubber and fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention [Field of Industrial Application] The present invention relates to an adhesive composition of rubber and fiber. More specifically, the present invention relates to an improved adhesive composition used for adhering rubber and reinforcing fibers contained in rubber products such as tires, belts and hoses.

[Conventional technology]

At present, nylon fibers and polyester fibers are widely used as rubber-reinforcing fibers. Adhesion between these fibers and rubber has already been made from butadiene-styrene-vinylpyridine copolymer latex and resorcin-formalin resin. An agent composition (hereinafter referred to as RFL) is used. As is apparent from the emulsion latex handbook (Page 187, published by Taisei Co., Ltd.), these commonly used copolymer latexes include butadiene, styrene, and 2-vinylpyridine as sodium oleate, sodium rosinate, and sodium laurylsulfonate. Alternatively, it is emulsion-polymerized using a low molecular weight emulsifier such as sodium naphthalene sulfonate of formaldehyde condensation.

[Problems to be Solved by the Invention] In general, multifilaments such as nylon and polyester fibers used for tire cords and the like are provided with adhesiveness to rubber by RFL treatment.

However, when the conventional RFL is used, there is a problem that the cutting strength and the cutting elongation are lower than those of the untreated fiber.

Further, since polyester fiber has less elongation and excellent dimensional stability as compared with nylon fiber, it has been widely used as a rubber-reinforcing fiber mainly in applications such as carcass cords of radial tires in recent years. The adhesive strength (heat resistant adhesive strength) between fibers and rubber after vulcanization or after high temperature history is severely reduced, and there is a problem in use in applications requiring high heat resistance.

Further, in the conventional RFL, it is desired to reduce the foamability of the RFL in that the foaming is severe and the processing operability of the fiber and the appearance of the treated fiber are improved.

In order to solve such a problem, the inventors of the present invention have earnestly studied a copolymer latex containing vinyl pyridine, and as a result, from a copolymer latex obtained by using a specific oligomer as a polymerization emulsifier and a resorcin-formalin resin. RFL is, there is little decrease in the cutting strength and cutting elongation of the fiber after the treatment, and rubber and fiber, particularly excellent in heat-resistant adhesive strength with polyester fiber, moreover, the foaming of RFL has found less adhesive composition, The present invention has been reached.

(B) Structure of the invention [Constitution of the present invention] That is, the present invention includes (A) 35 to 80% by weight of butadiene and 8 to 8% of vinylpyridine.
32% by weight and other monomers copolymerizable with them 0-57
With respect to 100 parts by weight of the monomer mixture (a) consisting of wt%,
100 parts by weight (solid content) of a copolymer latex obtained by using 0.2 to 10 parts by weight of the oligomer (b) represented by the following general formula (1) and / or (2) as a polymerization emulsifier, and (B) resorcin-formalin. A rubber-fiber adhesive composition comprising 7 to 30 parts by weight of a resin.

General formula Where R _{1 is} an alkyl group having 5 to 20 carbon atoms (general formula, represented by CnH ₂ n + ₁ ) R _{2 to} R _{7 is} hydrogen or an alkyl group having 1 to 5 carbon atoms (general formula, CnH ₂ n + ₁₎ Represented by), and a carboxyl group or a carboxymethyl group or their ammonium bases, amine bases, alkali metal bases or alkaline earth metal bases X: -COOC ₂ H ₄ OH, -COOC ₃ H ₆ OH, -CONHCH ₂ OH, -CONHC ₂ H
₅ , -CONHCH ₃ , -CONHC ₃ H ₇ , -COOCH ₃ , -CN, -OOCC
H ₃ , -OOCC ₂ H ₅ , (R ₈ : hydrogen, halogen or an alkyl group having 1 to 4 carbon atoms (general formula, represented by CnH ₂ n + ₁ )) Y: —OCH ₂ , —OC ₂ H ₅ , —CH ₂ OH, —N— (CH _{2) 3} -C =
O, or —COOR ₉ (R ₉ : hydrogen, ammonium salt, amine base, alkali metal or alkaline earth metal) Z: sulfonic acid group or — (CO) O—CnH ₂ nSO ₃ H or an alkali metal base thereof ( n = 1 to 4) a: Number of 0 to 100 b: Number of 1 to 100 c: Number of 1 to 100 Hereinafter, the present invention will be described in detail.

The monomer mixture (a) used in the present invention comprises 35 to 80% by weight of butadiene, 8 to 32% by weight of vinylpyridine, and 0 to 57% by weight of another monomer copolymerizable therewith.

If the butadiene content is less than 35% by weight, the adhesive strength will be reduced. Further, when the content of butadiene exceeds 80% by weight, the heat resistant adhesive strength decreases.

Examples of butadiene include 1,3-butadiene, 2-methyl-1,3-butadiene, and 2,3-dimethyl-1,3-butadiene. These are used alone or in combination of two or more. be able to.

If the vinyl pyridine content is less than 8% by weight or more than 35% by weight, the initial and heat resistant adhesive strength is lowered.

As vinyl pyridine, 2-vinyl pyridine, 3-vinyl pyridine, 4-vinyl pyridine, 2-methyl-5-
Examples thereof include vinyl pyridine, and these can be used alone or in combination of two or more.

When the amount of the other copolymerizable monomer exceeds 57% by weight, the initial and heat resistant adhesive strength is deteriorated.

Other copolymerizable monomers include, for example, styrene, α
-Aromatic vinyl monomers such as methylstyrene and monochlorostyrene, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, ethylenically unsaturated carboxylic acid alkyl ester monomers such as methyl methacrylate, ethyl acrylate and butyl acrylate Ethylenically unsaturated carboxylic acid hydroxy ester monomers such as β-hydroxyethyl acrylate and β-hydroxyethyl methacrylate, and ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid Examples thereof include a body, and these can be used alone or in combination of two or more. Among these, aromatic vinyl monomers, vinyl cyanide monomers and /
Alternatively, it is preferable to use an ethylenically unsaturated carboxylic acid monomer.

The oligomer (b) used in the present invention is used in an amount of 0.2 to 10 parts by weight based on 100 parts by weight of the monomer mixture (a). 0.
If it is less than 2 parts by weight, the effect as an emulsifier is lowered and a stable latex cannot be obtained, and if it exceeds 10 parts by weight, the initial and heat resistant adhesive strength is poor.

The molecular weight of the oligomer (b) used in the present invention is 500.
The molecular weight is preferably in the range of 1000 to 5000, and particularly preferably in the range of 1000 to 5000. When the molecular weight of the oligomer (b) is less than 500, the heat-resistant adhesive strength is lowered, and when it exceeds 10,000, the effect as an emulsifier is lowered.

As the polymerization method for obtaining the copolymer latex (A) of the present invention, a generally used emulsion polymer, that is, batch, semi-continuous, continuous or multi-step polymerization method, seed polymerization method or composition of added monomer is used. Any method such as a power feed polymerization method in which the ratio is continuously or intermittently changed can be adopted.

In addition, generally known chain transfer agents, initiators,
A polymerization aid such as a chelating agent or an electrolyte can be used.

The oligomer (b) used in the present invention can be used in combination with a conventionally known low molecular weight emulsifier within a range that does not impair the effects of the present invention. The amount is preferably 1 part by weight or less relative to 100 parts by weight of the body mixture (a).

Further, in the polymerization, when the polymerization is substantially completed, the pH of the latex is adjusted and the unreacted monomer is removed by stripping.

Further, within a range not impairing the effect of the present invention, a part of the copolymer latex (A) is obtained by using a conventionally known low molecular weight emulsifier, or the oligomer (b) of the present invention is used. Substitution with other latex other than the obtained (A) is sufficiently possible.

The adhesive composition of the present invention comprises a copolymer latex (A) 10
0 parts by weight (solid content) and 7 to 30 parts by weight of resorcin-formalin resin (B).

When the resorcin-formalin resin (B) is out of this range, the adhesive strength, the cutting strength and the cutting elongation are lowered.

Isocyanate, blocked isocyanate, ethylene urea, polyepoxide, modified polyvinyl chloride and the like can be appropriately added to the adhesive composition of the present invention.

Further, the oligomer (b) used in the present invention can be appropriately blended with the copolymer latex (A) or RFL, if necessary.

Fibers that can be used in the adhesive composition of the present invention include, but are not limited to, nylon fibers, polyester fibers, and aramid fibers.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to examples.
The present invention is not limited to these examples.

All parts used in the examples mean parts by weight unless otherwise specified.

Production of Copolymer Latex (A) To an autoclave previously purged with nitrogen, 130 parts of ion-exchanged water, 0.4 parts of sodium carbonate, the oligomer shown in Table 1 and the monomer mixture shown in Table 1 were added, and further t
-Add 0.5 parts of dodecyl mercaptan and emulsify. 1.5 parts of potassium persulfate was added, and the whole was kept at 50 ° C to carry out polymerization. When the polymerization conversion rate reaches 95%, 0.05 part of hydroquinone is added to terminate the polymerization. Then, the pH was adjusted to 7.0 with potassium hydroxide, and unreacted monomers were removed by distillation under reduced pressure to obtain copolymer latexes AF and copolymer latexes GK for comparison. Copolymer latex L
Was not obtained as a latex during the polymerization. Further, the following operations were performed to obtain comparative copolymer latexes M and N.

(Production of Copolymer Latex M) To an autoclave equipped with a stirrer, 130 parts of water, 4 parts of potassium rosinate, 1 part of sodium naphthalenesulfonate / formalin condensate and 0.5 part of sodium hydroxide are added and dissolved. To this, 70 parts of 1,3-butadiene, 15 parts of 2-vinylpyridine and 15 parts of styrene are added, and 0.5 part of t-dodecyl mercaptan is further added to emulsify. Then, 0.5 part of potassium persulfate is added and the whole is kept at 50 ° C. to carry out polymerization.
Once the polymerization conversion reached 92%, hydroquinone 0.1
Polymerization is stopped by adding parts. Unreacted monomers were removed from the obtained latex by vacuum distillation to obtain a copolymer latex M.

(Production of Copolymer Latex N) 130 parts of ion-exchanged water, 5 parts of polyoxyethylene lauryl ether,
0.5 parts of t-dodecyl mercaptan, 1,3-butadiene 68
Parts, 2-vinylpyridine 15 parts, styrene 15 parts, and itaconic acid 2 parts were added and emulsified. Polymerization was performed by keeping the whole at 50 ° C. When the polymerization conversion rate of the monomer mixture reached 95%, 0.1 part of hydroquinone was added to terminate the polymerization. Unreacted monomers were removed from the obtained latex by vacuum distillation to obtain a copolymer latex N.

Example-1 0.3 part of sodium hydroxide in 239 parts of water, 11 parts of resorcinol, 37
% Formalin (16.2 parts) was added and the mixture was aged at 25 ° C. for 6 hours to obtain a resorcin-formalin resin (RF resin).

Next, the obtained RF resin was added to 100 parts of the above-mentioned copolymer latex in the number shown in Table 2 and stirred. When the foaming at this time was visually observed, AK did not foam at all, but M and N foamed violently. Next, this was reacted at 25 ° C. for 18 hours to prepare RFL. This R
Nylon tire cord (1890 D / 2) was immersed in a single dipping machine for testing using FL.
The cutting strength and cutting elongation of the obtained cord are JIS-L-1017.
The results are shown in Table-2.

The untreated nylon tire cord had a breaking strength and a breaking elongation of 34.7 kg and 26.0%, respectively.

Then, the treated tire cord was sandwiched with a rubber compound manufactured according to the compounding formulation of Table 4, press-vulcanized at 145 ° C. for 30 minutes, and the adhesive force was measured by ASTM D2138-67 (H Pull Test method). The results are shown in Table-2.

Example-2: 333.5 parts of water, 1.3 parts of sodium hydroxide, 16.6 of resorcin
And 14.6 parts of 37% formalin were added, and the mixture was aged at 25 ° C. for 2 hours to obtain a resorcin-formalin resin. Next, the RF range obtained in 100 parts (solid content) of each of the above-mentioned copolymer latexes was added at the number of parts shown in Table 3, and reacted at 25 ° C. for 20 hours to obtain RFL. Next, 25 parts of VALCABOND E (manufactured by ICI Vulnax, 2,6-bis (2 ', 4'-dihydroxyphenylmethylene) -4-chlorophenol) was added. After adjusting this aqueous solution to a solid content concentration of 15%, a polyester tire cord (1500D / 2) was immersed using a test single cord dipping machine. This treated tire cord is sandwiched between rubber compounds produced according to the compounding recipe shown in Table 4 and at 45 ° C at 45 ° C.
Minutes and press vulcanized at 170 ° C. for 90 minutes. ASTM D2138
The adhesive strength was measured by -67 (H Pull Test method) to evaluate the decrease in adhesive strength due to high temperature history. The results are shown in Table-3.

Table-4 Compounded rubber prescription Natural rubber 40 parts SBR # 1502 60 parts SRF carbon 20 parts REF carbon 20 parts Pine tar 5 parts Styrenated phenol 2 parts Stearic acid 2.5 parts Zinc white 5 parts Vulcanization accelerator DM ^{* 7} 1.2 parts Sulfur 2.4 parts * 7: 2,2'-dithio-bis-benzothiazole ha Effect of the invention [Effect of the invention] The adhesive composition of the invention has a breaking strength of the fiber after the immersion treatment as compared with the conventional composition. And less decrease in cutting elongation,
In addition, it has excellent heat-resistant adhesive strength between rubber and fiber, especially polyester fiber, and has less foaming and excellent workability.

Claims (1)

[Claims] 1. A monomer mixture (a) comprising 100% by weight of (A) 35 to 80% by weight of butadiene, 8 to 32% by weight of vinylpyridine and 0 to 57% by weight of another monomer copolymerizable therewith. 100 parts by weight (solid content) of a copolymer latex obtained by using 0.2 to 10 parts by weight of the oligomer (b) represented by the following general formula (1) and / or (2) as a polymerization emulsifier, relative to the parts. ) A rubber-fiber adhesive composition comprising 7 to 30 parts by weight of a resorcin-formalin resin. General formula Where R _{1 is} an alkyl group having 5 to 20 carbon atoms (general formula, represented by CnH ₂ n + ₁ ) R _{2 to} R ₇ : hydrogen or an alkyl group having 1 to 5 carbon atoms (general formula, CnH ₂ n + ₁ Represented), and carboxyl groups or carboxymethyl groups or their ammonium bases, amine bases, alkali metal bases or alkaline earth metal bases X: -COOC ₂ H ₄ OH, -COOC ₃ H ₆ OH, -CONHCH ₂ OH , -CONHC ₂ H
₅ , -CONHCH ₃ , -CONHC ₃ H ₇ , -COOCH ₃ , -CN, -OOCC
H ₃ , -OOCC ₂ H ₅ , (R ₈ : hydrogen, halogen or an alkyl group having 1 to 4 carbon atoms (general formula, represented by CnH ₂ n + ₁ )) Y: —OCH ₂ , —OC ₂ H ₅ , —CH ₂ OH, —N— (CH _{2) 3} -C =
O, or —COOR ₉ (R ₉ : hydrogen, ammonium salt, amine base, alkali metal or alkaline earth metal) Z: sulfonic acid group or — (CO) O—CnH ₂ nSO ₃ H or an alkali metal base thereof ( n = 1 to 4) a: Number from 0 to 100 b: Number from 1 to 100 c: Number from 1 to 100