JPH06184505A - Adhesive composition for bonding rubber to fiber - Google Patents

Abstract

PURPOSE:To obtain an adhesive compsn. which is useful for bonding a fibrous reinforcement contained in a rubber article to the rubber and can prevent the degradation in tensile strength and elongation of a fiber cord by compounding a specific copolymer latex with a specified amt. of a resorcinol-formalin resin. CONSTITUTION:This adhesive compsn. comprises 100 pts.wt. (solid base) vinylpyridine-butadiene copolymer (e.g. a 2-vinylpyridine-1,3-butadiene-styrene copolymer) latex with 7-30 pts.wt. resorcinol-formalin resin. The copolymer latex is obtd. by the emulsion copolymn. using alkali metal and ammonium salts of a disproportionated rosin acid as emulsifiers, the salts being made from a disproportionated rosin acid contg. at least 60wt.% dehydroabietic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an adhesive composition of rubber and fiber. For more details, tires,
The present invention relates to an improved adhesive composition used for adhering rubber and reinforcing fibers contained in rubber products such as belts and hoses.

[0002]

2. Description of the Related Art Nylon fibers, polyester fibers, aramid fibers and the like are currently used as rubber reinforcing fibers. To bond these fibers and rubber,
An adhesive composition (hereinafter referred to as RFL) composed of a vinylpyridine-butadiene-based copolymer latex and a resorcin-formalin resin has been widely used. The vinylpyridine-butadiene-based copolymer latex currently used in this RFL is used in the production of the emulsion latex handbook (issued by Taisei Co., No. 187).
As is clear from the above, etc., sodium oleate, sodium rosinate, sodium lauryl sulfonate, formaldehyde condensed sodium naphthalene sulfonate and the like are used as main emulsifiers.

[0003]

Problems to be Solved by the Invention Generally, 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.

[0004]

[Means for Solving the Problems] In order to solve the above problems, the inventors of the present invention have diligently studied vinyl pyridine-butadiene copolymer latex, and as a result, set the dehydroabietic acid content to a specific ratio or more. RFL using a vinylpyridine-butadiene-based copolymer latex emulsion-polymerized by using an alkali metal salt and / or ammonium salt of disproportionated rosin acid as an emulsifier is used to cut fibers after treatment. The fact that the reduction in strength and cutting elongation can be significantly suppressed was found, and the present invention was completed.

That is, the present invention was emulsion-polymerized by using an alkali metal salt of disproportionated rosin acid and / or an ammonium salt of disproportionated rosin acid having a dehydroabietic acid content of 60% by weight or more as an emulsifier. Vinyl pyridine-butadiene copolymer latex (A) 100
Parts by weight (solid content) and resorcin-formalin resin (B)
The present invention provides an adhesive composition of rubber and fiber, which comprises 7 to 30 parts by weight.

The present invention will be described in detail below.

The vinyl pyridine-butadiene copolymer latex in the present invention is a copolymer which comprises vinyl pyridine and butadiene as main components, and optionally other copolymerizable monomers. It is a polymer latex.

Examples of butadiene include 1,3-butadiene, 2-methyl-1,3 butadiene, and 2,3-dimethyl-1,3-butadiene. These can be used alone or in combination of two or more. . In particular, the use of 1,3-butadiene is preferable.

Examples of vinyl pyridine include 2-vinyl pyridine, 3-vinyl pyridine, 4-vinyl pyridine and 2-vinyl pyridine.
Methyl-5-vinyl pyridine and the like can be mentioned, and one or more of these can be used. In particular, the use of 2-vinylpyridine is preferable.

Other copolymerizable monomers include aromatic vinyl monomers such as styrene, α-methylstyrene and monochlorostyrene, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, acrylic acid, Ethylenically unsaturated carboxylic acid monomers such as methacrylic acid, itaconic acid and fumaric acid, and ethylenically unsaturated carboxylic acid alkyl ester monomers such as methyl (meth) acrylate, ethyl (meth) acrylate and 2-ethylhexyl acrylate And the like, and one or more of these may be used. Use of styrene and acrylonitrile is particularly preferable.

There is no limitation on the monomer composition of the above-mentioned copolymer latex, but 35 to 90% by weight of butadiene, 3 to 40% by weight of vinylpyridine, and another monomer 5 which can be copolymerized. It is preferably about 62 to 62% by weight, more preferably 45 to 85% by weight of butadiene, 5 to 30% by weight of vinylpyridine, and 10 to 50% by weight of another copolymerizable monomer.

The present invention provides a disproportionated rosin acid alkali metal salt composed of disproportionated rosin acid having a dehydroabietic acid content of 60% by weight or more as an emulsifier when producing a vinylpyridine-butadiene copolymer latex. And / or ammonium salts are used.

In general, rosin acid is gum rosin acid obtained from raw pine resin collected from pine trees, wood rosin acid obtained by extracting petroleum-based solvent from pine stump, and cooking waste liquid during kraft pulp production. It is classified as tall oil rosin acid obtained from the above, but all of them have abietic acid as a main component because they are made from natural products, and when used as an emulsifying agent for polymerization, they are generally disproportionated by disproportionation reaction. Although it is used as a disproportionated rosin acid, the content of dehydroabietic acid in general industrially obtained disproportionated rosin acid is 55% by weight at most.

However, the disproportionated rosin acid in the present invention has a dehydroabietic acid content of 60% by weight or more, preferably 65% by weight or more, and more preferably 70% by weight or more.
It is more than weight%. If the content is less than 60% by weight, the object of the present invention cannot be achieved.

The disproportionated rosin acid having a dehydroabietic acid content of 60% by weight or more can be obtained by adjusting the amount of catalyst, temperature and the like during the disproportionation reaction. The emulsifier used in the present invention is a disproportionated rosin acid soap obtained by neutralizing such disproportionated rosin acid with an alkali metal such as sodium or potassium, or ammonia.
These may be used alone or in combination of two or more. Furthermore, the amount of the disproportionated rosin acid soap used in the present invention is not particularly limited, but it is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the monomer.

Further, in the emulsion polymerization method of the present invention, other conventionally known emulsifiers and dispersants other than disproportionated rosin acid soap can be used in combination. Other conventionally known emulsifiers include fatty acid sodium, fatty acid potassium, sodium lauryl sulfonate, polyoxyethylene lauryl ether, formalin condensate of sodium naphthalene sulfonate, and the like.

The copolymer latex of the present invention can be produced by a known emulsion polymerization method except that the emulsifier specified above is used. That is, a batch addition polymerization method, a division addition polymerization method, a continuous addition polymerization method, a two-step polymerization method, a power feed polymerization method, etc. can be adopted.

In the emulsion polymerization method of the present invention, conventionally known chain transfer agents, polymerization initiators, electrolytes, polymerization accelerators, chelating agents and the like can be used.

The chain transfer agent used in the emulsion polymerization of the copolymer latex of the present invention includes alkyl mercaptans represented by t-dodecyl mercaptan and the like, xanthogen compounds, thiuram compounds, styrenated phenol and the like. Phenol compounds, allyl compounds such as allyl alcohol, halogenated hydrocarbon compounds such as carbon tetrachloride, vinyl ethers such as α-benzyloxystyrene, thioglycolic acid, thiomalic acid, α-methylstyrene dimer, and terpinolene. ,
These may be used alone or in combination of two or more.

Examples of the polymerization initiator used in the emulsion polymerization of the copolymer latex of the present invention include water-soluble polymerization initiators such as potassium persulfate, sodium persulfate and ammonium persulfate, redox type polymerization initiators and benzoyl peroxide. Oil-soluble polymerization initiators such as can be appropriately used.

The adhesive composition (RFL) of the present invention contains 100 parts by weight (solid content) of the copolymer latex (A) and 7 to 30 parts by weight (solid content) of resorcin-formalin resin (B). is necessary. If the amount of the resorcin-formalin resin (B) used is out of this range, the adhesive strength between the treated fiber and the rubber will be reduced, and the cutting strength and elongation of the treated fiber will be reduced.

This adhesive composition contains, in addition to the copolymer latex obtained in the present invention, natural rubber latex and SBR.
Latex, NBR latex, MBR latex, and modified latex thereof may be blended as necessary.

Further, the adhesive composition contains isocyanate, blocked isocyanate, ethylene urea, 2,
6-bis (2 ', 4'-dihydroxyphenylmethylene) -4-chlorophenol, polyepoxide, modified polyvinyl chloride, carbon black and other adhesion aids, fillers, crosslinking agents, vulcanizing agents, vulcanization accelerators, etc. It may be mixed if necessary.

Fibers for which the adhesive composition of the present invention is used include nylon fiber, polyester fiber, aramid fiber and the like, but are not particularly limited thereto, and
These fibers may be in any form such as cords, cables, fabrics, canvas and staple fibers.

As the rubber to be bonded to the fiber treated with the adhesive composition of the present invention, natural rubber, SBR, N
Examples thereof include BR, chloroprene rubber, polybutadiene rubber, polyisoprene rubber, and various modified rubbers thereof, but are not particularly limited thereto.

[0026]

EXAMPLES and COMPARATIVE EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples in order to clearly show the excellent effects of the present invention. , But not limited to these examples. In the examples and comparative examples, parts and percentages indicating ratios are based on weight unless otherwise specified.

Method for producing copolymer latex 130 parts of ion-exchanged water was charged into an autoclave previously purged with nitrogen, 0.4 part of sodium carbonate and the emulsifier shown in Table 1 were added and dissolved. To this, 15 parts of 2-vinylpyridine, 70 parts of 1,3-butadiene and 15 parts of styrene were added, and 0.5 part of t-dodecyl mercaptan was further added to emulsify the mixture, followed by addition of 0.5 part of potassium persulfate. The whole was kept at 50 ° C. to initiate polymerization. Polymerization conversion rate is 95
When it reached%, 0.1 part of hydroquinone was added to terminate the polymerization. Then, the pH was adjusted to 11. with potassium hydroxide.
After adjusting to 0, unreacted monomers were removed by vacuum distillation to obtain copolymer latexes A-1 to A-6.

0.3 part of sodium hydroxide and 1 part of resorcinol in 239 parts of adjusted water of RFL solution
Add 1 part and dissolve. 37% formalin 1
6.2 parts was added and the mixture was aged at 25 ° C. for 6 hours to obtain a resorcin-formalin resin (RF resin). Next, 100 parts (solid content) of the above-mentioned copolymer latex was mixed with the obtained RF resin in the number of parts shown in Table 2, stirred and then aged at 25 ° C. for 18 hours to prepare RFL solutions 1 to 8
It was created.

Tire cord dipping treatment, cord cutting strength
Using a single cord dipping machine for the test of measuring the cutting and elongation, the nylon tire cord (1890
D / 2) immersion treatment was performed. The cut strength and cut elongation of the obtained treated cord were measured according to JIS-L-1017, and the results are shown in Table 2. The untreated nylon tire cord had a breaking strength and breaking elongation of 34.7 kg and 27.0%, respectively.

Adhesion Measurement Next, the treated tire cord was pinched with a rubber compound prepared according to the compounding recipe of Table 3 at 145 ° C. and 30 ° C.
Press vulcanize for minutes, ASTM D2138-67 (H
The adhesive force was measured by the Pull Test method). The results are shown in Table 2.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

As described above, the adhesive composition of the present invention is
The treated fiber cord has little reduction in cutting strength and cutting elongation, and also has excellent adhesive force with rubber, which is very useful in practical use.

Claims (1)

[Claims] 1. A vinylpyridine-butadiene emulsion-polymerized by using an alkali metal salt of disproportionated rosin acid and / or an ammonium salt of disproportionated rosin acid having a dehydroabietic acid content of 60% by weight or more as an emulsifier. An adhesive composition of rubber and fiber, which comprises 100 parts by weight (solid content) of the system copolymer latex (A) and 7 to 30 parts by weight of the resorcin-formalin resin (B).