JPH06184247A - Production of copolymer latex and adhesive composition for bonding rubber to fiber - Google Patents

Abstract

PURPOSE:To obtain the subject latex having low viscosity, excellent in mechanical stability and productivity and useful as an adhesive, etc., by polymerizing vinylpyridine with butadiene, etc., using a specific emulsifier for polymerization. CONSTITUTION:Vinylpyridine, butadiene, etc., is polymerized by combinedly using sodium rosinate and potassium rosinate as emulsifiers for polymerization in a weight ratio of sodium rosinate/potassium rosinate of (3/7) to (9/1) to provide the objective latex. Furthermore, 100 pts.wt. (as a solid content) of the latex is blended with 5-35 pts.wt (as a solid content) resorcinol-formalin resin to provide the objective adhesive composition for bonding rubber to fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a vinylpyridine-butadiene copolymer latex and an adhesive composition of rubber and fiber using the copolymer latex. More specifically, an improved production of vinyl pyridine-butadiene copolymer latex used with resorcin-formalin resin as an adhesive between reinforcing fibers and rubber contained in rubber products such as tires, belts and hoses. The present invention relates to a method and an adhesive composition thereof.

[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 JP-A-60-92371, sodium oleate, sodium rosinate, sodium lauryl sulfonate, potassium rosinate and the like are used as main emulsifiers.

However, when a vinyl pyridine-butadiene copolymer latex is produced by a conventionally known method using the above-mentioned conventionally known emulsifiers, many agglomerates are generated during the production, resulting in poor productivity, or There was a problem that the viscosity of the obtained copolymer latex was high and at the same time its mechanical stability was poor and the workability during production was poor. Further, since the mechanical stability of RFL composed of such a copolymer latex and resorcin-formalin resin is poor, aggregates are generated in the step of dipping the fiber in RFL and the treatment is not preferable for the treated product. There is a problem that foreign matter may be attached to reduce the commercial value, or foreign matter may be attached to each part of the dipping machine (immersion processing machine) during the dipping process or the drying process after the dipping process, resulting in a significant decrease in productivity. there were.

On the other hand, long-fiber multifilaments such as nylon fibers, polyester fibers, and aramid fibers used for tire cords and the like have also been provided with rubber by the RFL treatment as described above. Is not yet sufficient, and has a drawback that the cutting strength of the RFL-treated fiber is lower than that before the treatment, and the properties of the fiber itself are impaired.

[0005]

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present inventors have made diligent studies to solve the problems at present, and as a result, in producing a vinylpyridine-butadiene-based copolymer latex, A vinylpyridine-butadiene-based copolymer latex emulsion-copolymerized by using sodium rosinate and potassium rosinate as emulsifiers together and using a sodium rosinate / potassium rosinate weight ratio within a specific range, The present inventors have found that RFL composed of a copolymer latex and a resorcin-formalin resin can solve all of the above problems at the same time, and completed the present invention.

That is, according to the present invention, when a vinylpyridine-butadiene-based copolymer latex is produced, sodium rosinate and potassium rosinate are used together as an emulsifying agent for polymerization, and a weight ratio of sodium rosinate / potassium rosinate is used. Is used in the range of 3/7 to 9/1, and a method for producing a copolymer latex, and an adhesive composition of a rubber and a fiber comprising the copolymer latex and a resorcin-formalin resin are provided. It is a thing.

The present invention will be described in detail below.

The vinyl pyridine-butadiene copolymer latex in the present invention is a copolymer comprising 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 and methacryl. Ethylenically unsaturated carboxylic acid monomers such as acids, 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 one or more of these can be used. It is particularly preferable to use styrene, acrylonitrile, or methyl methacrylate.

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 vinyl pyridine, and other copolymerizable monomer 5 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 is characterized by the combined use of sodium rosinate and potassium rosinate as emulsifiers in a specific ratio when producing a vinylpyridine-butadiene copolymer latex. Generally, rosin acid is a gum rosin acid obtained from raw pine resin collected from a pine tree.
Wood rosin acid obtained by extracting from a pine stump with a petroleum solvent, and tall oil rosin acid obtained from cooking waste liquid at the time of kraft pulp production are classified as abietic acid because they are all natural products. Although it is a main component, it contains neoabietic acid, parastophosphoric acid, dehydroabietic acid, pimaric acid, isopimaric acid and the like as minor components. Disproportionated rosin acid is obtained by the disproportionation reaction. The sodium rosinate and potassium rosinate used in the present invention are disproportionated rosin acid soaps obtained by neutralizing the disproportionated rosin acid with sodium and potassium, respectively.

The weight ratio of sodium rosinate / potassium rosinate used in the present invention must be 3/7 to 9/1. If this weight ratio is less than 3/7, the amount of aggregates generated during production increases, and the viscosity of the obtained copolymer latex increases, and at the same time, not only the latex but also the RFL mechanical stability decreases. Moreover, the adhesive force between the rubber and the fiber is reduced. Also, this weight ratio is 9
If it exceeds / 1, the amount of aggregates generated during production increases, and at the same time, the mechanical stability of the copolymer latex and RFL decreases, and further the cutting strength of the treated fiber decreases.

The amount of disproportionated rosin acid soap used in the present invention is not particularly limited, but it is preferably used in the range of 0.1 to 10 parts by weight, more preferably 0, based on 100 parts by weight of the monomer. 0.5 to 8 parts by weight.

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 of the above-mentioned copolymer latex (solid content) and 5 to 35 parts by weight of the resorcin-formalin resin (solid content) as its main components. is necessary. When the amount of the resorcin-formalin resin is less than 5 parts by weight, the mechanical stability of RFL and the adhesive force between the treated fiber and the rubber are decreased, and when the amount exceeds 35 parts by weight, the breaking strength of the treated fiber and the strength with the rubber are reduced. The adhesive strength is reduced. It is preferably 7 to 30 parts by weight.

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 polymerization water was charged into a pressure resistant polymerization reactor, to which 1.0 part of formalin condensate of sodium naphthalenesulfonate, 0.5 part of sodium hydroxide, and Table 1 were added. Add the emulsifier shown in to dissolve. 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 90-
When it reached 95%, 0.1 part of hydroquinone was added to terminate the polymerization, and unreacted monomers were removed by steam distillation to obtain copolymer latices AF. Further, the evaluation of the copolymer latex in Examples and Comparative Examples was carried out according to the following method.

Copolymer latex 500 g of a copolymer latex obtained by polymerizing the amount of aggregate in 200
The mixture is filtered through a mesh of wire mesh, the agglomerates captured by the wire mesh are dried, and then the weight thereof is measured. The following three-stage evaluation was performed according to the measured weight of the aggregate. ○: less than 0.2 g △: 0.2 g or more and less than 2 g × ... 2 g or more

Viscosity of copolymer latex The viscosity of the copolymer latex was measured according to JIS K6381. The following three-stage evaluation was performed according to the measured viscosity value. ○ ・ ・ ・ less than 50 cps △ ・ ・ ・ 50 cps or more and less than 200 cps × ・ ・ ・ 200 cps or more

Mechanical Stability of Copolymer Latex According to the method shown in JIS K6387-1982 as a reference, a test was conducted under the conditions of a load of 5 kg and a rotation time of 5 minutes to determine the coagulation rate (%). The following three-stage evaluation was performed according to the obtained solidification rate (%). ○: less than 0.2% △: 0.2% or more and less than 2% × ... 2% or more

[0031]

[Table 1]

Preparation of RFL solution (1) 0.3 part of sodium hydroxide and 1 part of resorcin in 239 parts of water
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 9
It was created.

Mechanical Stability of RFL Solution (1) The mechanical stability of the obtained RFL solution was measured according to JIS K6387.
According to the method shown as a reference in -1982, the load was measured at 5 kg and the rotation time was 5 minutes, and the following three-stage evaluation was performed according to the obtained solidification rate (%). The results are shown in Table 2. ○: less than 0.2% △: 0.2% or more and less than 2% × ... 2% or more

Tire cord dipping treatment, cord cutting strength
And adhesive strength measurement (1) Nylon tire cord (1260) was obtained from the obtained RFL liquid using a test single cord dipping machine.
D / 3) immersion treatment was performed. The breaking strength of the obtained treated cord was measured according to JIS-L-1017, and the results are shown in Table 2. Then, the obtained processing code is shown in Table 4.
Scissors with a rubber compound manufactured with the compounding recipe of 145 ° C
Press vulcanize for 30 minutes at ASTM D2138-67
The adhesive force was measured according to (H pull test method). The results are shown in Table 2.

Preparation of RFL Solution (2) To 333.5 parts of water, 1.3 parts of sodium hydroxide and 16.6 parts of resorcin are added and dissolved. To this was added 14.6 parts of 37% formalin and the mixture was aged at 25 ° C. for 2 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 3,
After stirring, age it at 25 ° C. for 20 hours, then
35 parts of VALCABOND E (manufactured by ICI Vulnax) was added to prepare RFL solutions 11 to 19.

Mechanical Stability of RFL Solution (2) The mechanical stability of the obtained RFL solution was measured according to JIS K6387.
According to the method shown as a reference in -1982, the load was measured at 5 kg and the rotation time was 5 minutes, and the following three-stage evaluation was performed according to the obtained solidification rate (%). The results are shown in Table 3. ○: less than 0.2% △: 0.2% or more and less than 2% × ... 2% or more

Tire cord dipping treatment, cord cutting strength
And adhesive strength measurement (2) Using a single cord dipping machine for testing, the obtained RFL liquid was used for polyester tire cord (15
Immersion treatment of 00D / 2) was performed. The breaking strength of the obtained treated cord was measured according to JIS-L-1017, and the results are shown in Table 3. Then, the obtained treatment code was sandwiched between rubber compounds manufactured by the compounding recipes in Table 5, and 14
After press vulcanization under two conditions of 5 ° C. for 30 minutes and 170 ° C. for 80 minutes, according to ASTM D2138-67 (H pull test method), the adhesive strength under the general vulcanizing conditions (initial adhesive strength) and after high temperature history The adhesive strength (heat resistant adhesive strength) of each was measured. The results are shown in Table 3.

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

[0042]

As described above, the method for producing a copolymer latex of the present invention suppresses the amount of aggregates generated during production to be extremely low, and at the same time that the viscosity of the obtained copolymer latex is low, Since the mechanical stability is extremely excellent, the productivity is remarkably improved, and a method for producing a vinylpyridine-butadiene-based copolymer latex which is extremely industrially useful is provided. Further, the RFL comprising the obtained copolymer latex and resorcin-formalin resin is also excellent in mechanical stability, the adhesive force between the rubber and the fiber is excellent, and the cutting strength of the treated fiber is not significantly reduced. Very practically useful.

Claims (2)

[Claims] 1. When producing a vinyl pyridine-butadiene copolymer latex, sodium rosinate and potassium rosinate are used together as an emulsifying agent for polymerization, and the weight ratio of sodium rosinate / potassium rosinate is 3/7. ~
A method for producing a copolymer latex, which is used in the range of 9/1. 2. A rubber comprising 100 parts by weight (solid content) of the copolymer latex obtained by the production method according to claim 1 and 5 to 35 parts by weight (solid content) of resorcin-formalin resin. Adhesive composition with fibers.