JPH1088092A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive compsn. which hardly exhibits the degradation in adhesion even when used continuously at high temps. by compounding a latex with a thermosetting resin and a specific dithio compd. SOLUTION: An adhesive compsn. useful for bonding a rubber to org. fibers is obtd. by compounding a latex with at least one thermosetting resin (e.g. a resorcin-formaldehyde resin or a phenol-formaldehyde resin), 0.3-6.1wt.% (based on the solid content of the compsn.; the same applies thereunder) at least one dithio compd. represented by formula I [R1 is C2 H4 OH or group represented by formula II (X is OH, COOH, or NO) or formula III], 0.3-4.9wt.% at least one monophenol compd. represented by formula IV (R2 is CH3 or t-Bu; R3 is t-Bu or C8 H17 S; and R4 is CH3 or C8 H17 S), 0.3-5.8wt.% at least one tert. phosphorus compd. represented by formula V (R5 is CH3 ), and if necessary additives such as a vulcanization retarder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive composition for a fiber material.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of energy saving, tires and the like have become lighter in weight.
There is a need for improved stability against thermal input and improved fracture life. As a result, the demand for fiber materials as reinforcing materials for articles such as tires, conveyor belts, belts, hoses, air springs, etc. has been further increased.

[0003] Fiber materials are used in the form of filaments, cords, cables, cord fabrics, canvases, etc.
In order to satisfy such a reinforcing purpose, it is important that the fibrous material is firmly bonded to the rubber, which affects the product life of the rubber article and various performances which are the objectives of the product. Not too much.

Conventionally, an adhesive obtained by dispersing a resin such as resorcin-formaldehyde resin, urea-formaldehyde resin, and phenol derivative-formaldehyde resin in a rubber latex to bond a fiber material and rubber has been used. It is used. Among them, the most widely used is an adhesive obtained by dispersing a resordin-formaldehyde resin in a rubber latex.

Here, as the rubber latex, one or a mixture of plural kinds of vinyl pyridine-styrene-butadiene terpolymer latex, styrene-butadiene copolymer latex, natural rubber latex and the like are used. .

[0006] The method of using these adhesives is to apply an adhesive to a fiber material, heat-treat to bond the adhesive and the fiber, embed the fiber material in rubber, and simultaneously cure the compounded rubber with vulcanization. It is common to combine a compounded rubber with a fiber material. The adhesive used in this method is a so-called rubber latex-based adhesive and is called a rubber vulcanized adhesive. However, in recent years, the vulcanization temperature of tires and the like has tended to increase from the viewpoint of improving productivity, and in order to cope with these severe thermal inputs, rubber-fiber adhesion stability and breaking life have been reduced. It is very important to measure the improvement.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adhesive composition which shows little adhesive deterioration even in continuous use at high temperatures.

[0008]

The first aspect of the present invention is as follows.
The raw latex and the thermosetting resin contain at least one dithio compound represented by the following general formula (1), and the compounding amount thereof is 0.3 to 6.1% by weight of the solid content weight of the adhesive composition. An adhesive composition characterized by being

Embedded image When the dithio compound represented by the general formula (1) is dithiodiethanol, bis (4-nitrophenyl) disulfide, bis (m-benzoic acid) disulfide, bis (resorcinol) disulfide, and thioperoxydiphosphoric acid tetrakis (1) More preferably, it is at least one member selected from the group consisting of (-methylethyl) ester. A second aspect of the present invention is that the raw latex and the thermosetting resin contain at least one monophenol represented by the following general formula (2), and the amount of the monophenol is 0% of the solid weight of the adhesive composition. 0.3 to 4.9% by weight of the adhesive composition,

Embedded image The compound represented by the general formula (2) is 2,6-di-
(T-butyl) -4-methylphenol, and 2,
It is preferably at least one selected from the group of compounds of 4-bis [(octylthio) methyl] -o-cresol. Further, a third aspect of the present invention is that the raw material latex and the thermosetting resin contain at least one tertiary phosphorus compound represented by the following general formula (3), and the amount of the tertiary phosphorus compound is the solid content weight of the adhesive composition. 0.3 to 5.8% by weight of the adhesive composition,

Embedded image The compound represented by the general formula (3) is preferably tris (nonylphenyl) phosphite. The rubber compositions according to these inventions are particularly useful for bonding rubber and fibers, and are particularly effective when the fibers are organic fibers.

Various compounds used in the present invention are added to control crosslinking. As such an additive, an effect of delaying and suppressing adhesion deterioration can be obtained as long as it can capture generated radicals, such as a rubber vulcanization retarding compounding agent, and particularly preferably, an adhesive composition. It is preferable to use those which are soluble in water or those which can be emulsified with a liquid because they are uniformly dispersed in the adhesive composition. Specifically, the above compounds are preferable, but these may be used alone or in combination of two or more.

The amount of the additive used in the present invention varies depending on the type of the compound used. For the compound represented by the formula (1), the amount of the additive is 0.3 to 6.1% by weight, and preferably 0.3 to 6.1% by weight. , 2.0 to 3.8% by weight, in the compound represented by (2), 0.3 to 4.9% by weight, preferably 1.2 to 3.3% by weight, the compound represented by (3) Then, 0.3 to 5.8% by weight, preferably 0.4 to
It is 4.5% by weight. More specifically, dithiodiethanol is 0.3 to 3.8% by weight, bis (4-nitrophenyl) disulfide is 0.3 to 3.8% by weight, and bis (m −
Benzoic acid) disulfide is 0.3 to 4.2% by weight, bis (resorcinol) disulfide is 0.3 to 5.0% by weight,
Thioperoxydiphosphoric acid tetrakis- (1
-Methylethyl) ester is from 0.3 to 6.1% by weight,
2,6-dimethyl-t-butyl-4-methylphenol is 0.3 to 3.9% by weight, and 2,4-bis [(octylthio) methyl] -o-cresol is 0.3 to 4.9% by weight. , Tris (0.3% for nonylphenyl phosphite)
It is preferable to add 5.8% by weight. Examples of the raw material latex used in the present invention include natural rubber latex, styrene-butadiene copolymer latex, and vinylpyridine-styrene-butadiene copolymer latex. These rubber components may be used alone or as a mixture of two or more. It is particularly preferable to include a vinylpyridine-styrene-butadiene copolymer latex.

The thermosetting resin used in the present invention includes resorcin-formaldehyde resin, phenol-
Formaldehyde resin, urea-formaldehyde resin,
Melamine-formaldehyde resin, phenol derivative-
Formaldehyde resin and the like, preferably, resorcin-formaldehyde condensate synthesized under an alkali catalyst, urea-formaldehyde condensate synthesized under an alkali catalyst, or resorcin-formaldehyde condensate synthesized under an alkali catalyst And a phenol derivative-formaldehyde condensate mixture synthesized under acidic or neutral conditions. Specific examples include 3,5-xylenol-formaldehyde resin and 5-methylresorcin-formaldehyde resin, and these may be used alone or in combination of two or more.

The adhesive composition of the present invention comprises aliphatic polyamide fibers such as rayon, vinylon, 6-nylon, 6,6-nylon and 4,6-nylon, and aromatic polyamide fibers represented by paraphenylene terephthalamide. It can be used for all fiber materials used for reinforcing rubber articles such as polyester fibers represented by polyethylene terephthalate. Here, for aromatic polyamide fiber, polyester fiber and other fiber materials,
It can be applied to those processed with phenol derivative-formaldehyde resin, epoxy compound, isocyanate compound, etc. in the fiber polymerization / spinning process or post-treatment process, and further processed in advance by electron beam, microwave, plasma treatment, etc. The adhesive composition of the present invention can also be applied to a fibrous material.

In using the adhesive composition of the present invention,
The form of the fiber material is not particularly limited, for example, cord,
It can be used for cables, filaments, filament chips, cord fabrics, canvas and the like.

When the additives are dispersed in the adhesive composition,
Use a surfactant. The type of the surfactant is not particularly limited, and any surfactant can be used as long as the additive used can be dispersed. Particularly preferred is sodium dodecyl sulfonate, which can disperse additives in small amounts.

The method of mixing the additives is not particularly limited, but a preferred method is to dissolve or disperse the additives in water and then mix the resulting mixture with a composition comprising a raw latex and a thermosetting resin.

The method for adhering the adhesive of the present invention to the surface of the fiber is not particularly limited. For example, the fiber material is dipped in the adhesive composition, applied with a doctor knife or brush, spray-applied, or And a method of pulverization and spray application.

The amount of the adhesive to be applied varies depending on the use and is not particularly limited. For example, as a cord for a tire, for example, 100 parts by weight of a fiber material and adhesive compositions 1-2 are used.
It is preferably 0 parts by weight, more preferably 2 to 7 parts by weight.
Parts by weight. Further, it is preferable that the adhesive composition is uniformly applied to the cord surface.

The fiber material after application of the adhesive composition of the present invention can be subjected to heat treatment, electron beam treatment, microwave treatment, plasma treatment, etc. at a temperature of 100 to 250 ° C. after drying.

In the present invention, in addition to these, if necessary, compounding agents usually used in the textile industry, for example, an antifoaming agent, an adhesion promoter and the like are appropriately compounded according to the purpose. be able to.

The fiber material treated with the adhesive composition of the present invention can be applied to any rubber articles such as tires, conveyor belts, belts, hoses, air springs and the like.

In general, in the vulcanization step in rubber article processing, the adhesive layer is cross-linked more than necessary by a cross-linking agent that diffuses and migrates from the compounded rubber composition into the latex rubber. As a result, the modulus of elasticity of the adhesive layer increases more than desired and the volume changes, so that stress is generated here. When this stress is concentrated between the adhesive layer and the fiber, the adhesive strength is reduced. In particular, under a high temperature or a long-time heating (including heat generated by a mechanical input), this tendency is remarkable, and a change in physical properties of the adhesive layer becomes large, so that adhesive deterioration is remarkable.

In the present invention, dithio compounds (general formula (1)), monophenols (general formula (2)), or
By adding a tertiary phosphoric acid compound (general formula (3)), a reactive sulfur species (Sn radical (n is an integer of 1 to 8)) which has migrated and diffused from the compounded rubber is captured ( Dithio compounds) or Sn. (Monophenols and tertiary phosphoric acid compounds) to limit the number of active sulfur and moderately control the cross-linking reaction. It is also possible to provide an adhesive composition characterized by suppressing adhesion deterioration due to a change in physical properties of the adhesive layer even below.

[0023]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited thereto without departing from the gist of the present invention. Parts and% in Examples are based on weight unless otherwise specified.

1) Preparation of Adhesive Composition A resorcinol-formaldehyde resin solution was prepared according to the composition shown in Table 1 below, and aged at room temperature for 8 hours. Table 1 Water 524.01 parts by weight Resorcinol 15.12 parts by weight Formalin (37%) 16.72 parts by weight Caustic soda (10%) 11.00 parts by weight

To the obtained resorcinol-formaldehyde resin solution, 433.15 parts by weight of a vinylpyridine-styrene-butadiene terpolymer (40%) was added, and
Sodium dodecyl sulfonate 0.004 as emulsifier
After the addition of parts by weight, predetermined additives shown in Tables 4 to 6 were blended and aged at room temperature for 6 hours to obtain an adhesive composition. The solid content concentration of the obtained adhesive was measured according to JIS K6839 and other methods for measuring the non-volatile content of the adhesive.

2) Preparation of adhesive treatment cord 1500 of poly (1,4-phenyleneterephthalamide) (trade name: Kevlar, manufactured by DuPont) as a fiber material
The denier yarn is twisted 32 times / 10 cm, and the two yarns are twisted 32 times / 10 cm.
Got the code.

Next, this cord was immersed in an epoxy compound aqueous solution shown in Table 2, dried at 160 ° C. for 60 seconds, and further heat-treated at 240 ° C. for 60 seconds to obtain a pre-treated cord.
This pretreatment code was immersed in the adhesive composition shown in Table 2, and
The adhesive composition was dried at 0 ° C. for 60 seconds and heat-treated at 240 ° C. for 60 seconds to prepare an adhesive composition treated cord.

Table 2 Diglycerol triglycidyl ether 1.20 parts by weight Sodium dioctyl sulfosuccinate 0.02 parts by weight Caustic soda (10%) 0.14 parts by weight Water 98.64 parts by weight

3) Preparation of Compounded Rubber A compounded rubber composition for embedding cords was prepared according to Table 3.

Table 3 NR (RSS # 3) 80 parts by weight IR 20 parts by weight Carbon black 40 parts by weight Stearic acid 2 parts by weight Petroleum-based softener 10 parts by weight Pinetal 4 parts by weight Zinc white 5 parts by weight N-phenyl-β -Naphthylamine 1.5 parts by weight 2-benzothiazyl disulfide 0.75 parts by weight Diphenylguanidine 0.75 parts by weight Sulfur 2.5 parts by weight 4) Adhesion test The adhesion was measured by the following method. a) Initial adhesive strength The adhesive composition-treated cord was embedded in an unvulcanized compounded rubber composition and vulcanized at 170 ° C. for 30 minutes under a pressure of 20 kg / cm ² to obtain a test piece. A cord was dug up from the obtained test piece, and the resistance at the time of peeling the cord from the vulcanizate at a speed of 30 cm / min was defined as the initial adhesive strength. b) Heat resistant adhesive strength The adhesive composition-treated cord was embedded in an unvulcanized compounded rubber composition, and vulcanized at 190 ° C. for 30 minutes under a pressure of 20 kg / cm ² to obtain a test piece. A cord was dug up from the obtained test piece, and the resistance at the time of peeling the cord from the vulcanizate at a speed of 30 cm / min was defined as the heat resistance.

[Examples 1 to 19, Comparative Examples 1 to 6] This is an example in which a dithio compound is used as an additive. Table 4 shows the obtained initial adhesive strength and heat resistant adhesive strength.

[0032]

[Table 4-1]

[Table 4-2]

Comparative Example 1 is a control system containing no additive, Examples 1 to 3 and Comparative Example 2 are examples in which dithiodiethanol is used as a dithioide, and Examples 4 to 6 and Comparative Example 3 are examples in which a dithioide is used. Examples using bis (4-nitrophenyl) disulfide, Examples 7 to 11 and Comparative Example 4, Examples 12 to 14 and Comparative Example 5 are examples using bis (m-benzoic acid) disulfide as a dithioide.
In Examples 15 to 19 and Comparative Example 6, thioperoxydiphosphoric acid tetrakis- (1,
This is an example using 4-methylethyl) ester. Each examines the change in adhesive strength by changing the amount of dithioides. By blending dithioides,
It can be seen that both the initial adhesive strength and the heat resistant adhesive strength are improved, and that the amount of dithioide has an optimum point.

Examples 20 to 26, Comparative Examples 1, 7 to 9
This is an example in which a monophenol is used as an additive. Table 5 shows the obtained results.

[0035]

[Table 5]

Comparative Example 1 is a control system containing no additive, Examples 20 to 22 and Comparative Example 7 are examples using 2,6-di-t-butyl-4-methylphenol as monophenols, Examples 23 to 27 and Comparative Example 8,
Reference numeral 9 is an example using 2,4-bis {(octylthio) methyl} disulfide as the monophenols. Each of them is examining a change in the adhesive force by changing the amount of the monophenols. By blending, both initial adhesive strength and heat resistant adhesive strength are improved,
It can be seen that there is an optimum point for the amount of monophenol.

[Examples 27 to 32, Comparative Examples 1 and 10] Examples in which a polyphosphate compound was used as an additive. Table 6 shows the obtained results.

[0038]

[Table 6]

Comparative Example 1 is a control system containing no additive, and Examples 27 to 32 and Comparative Example 10 are all examples using tris (nonylphenyl) phosphite as the tertiary phosphorus compound. Each examines the change in adhesive strength by changing the amount of the tertiary phosphorus compound, and by adding the tertiary phosphorus compound, the initial adhesive strength and the heat-resistant adhesive strength are also improved. It can be seen that the amount has an optimum point.

[0040]

[Effect] By incorporating an additive into the adhesive composition for cord processing, it is possible to particularly suppress the adhesive deterioration at a high temperature.

Claims (8)

[Claims] The raw material latex and the thermosetting resin contain at least one dithio compound represented by the following general formula (1), and the compounding amount thereof is 0.3 to 6 based on the weight of the solid content of the adhesive composition. 0.1% by weight of the adhesive composition. Embedded image 2. The dithio compound represented by the general formula (1) is dithiodiethanol, bis (4-nitrophenyl) disulfide, bis (m-benzoic acid) disulfide, bis (resorcinol) disulfide, and thioperoxydiphos. The adhesive composition according to claim 1, wherein the adhesive composition is at least one selected from the group consisting of hollic acid tetrakis (1-methylethyl) ester. 3. The raw material latex and the thermosetting resin contain at least one monophenol represented by the following general formula (2), and the compounding amount thereof is 0.3 to 4 of the solid weight of the adhesive composition. An adhesive composition characterized by being 0.9% by weight. Embedded image 4. The compound represented by the general formula (2) is 2,6-di- (t-butyl) -4-methylphenol,
And 2,4-bis [(octylthio) methyl] -o
The adhesive composition according to claim 3, wherein the adhesive composition is at least one selected from the group consisting of -cresol. 5. The raw material latex and the thermosetting resin contain at least one tertiary phosphorus compound represented by the following general formula (3), and the content thereof is 0.3% of the solid weight of the adhesive composition. An adhesive composition characterized in that the content is from about 5.8% by weight to about 5.8% by weight. Embedded image 6. The adhesive composition according to claim 5, wherein the compound represented by the general formula (3) is tris (nonylphenyl) phosphite. 7. The adhesive composition according to any one of claims 1 to 6, for bonding rubber and fiber. 8. The adhesive composition according to claim 1, wherein the fibers are organic fibers.