JPH0978045A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive composition having increased adhesive force and heat resistance by blending a latex obtained by partial polymerization of a mixture comprising different content of vinylpyridine, styrene and butadiene with a thermosetting resin at a prescribed weight ratio of gel/sol. SOLUTION: The objective adhesive composition having increased adhesive force and heat resistance and used for bonding a fiber material with rubber is obtained by blending a latex containing vinylpyridine-styrene-butadiene terpolymer granules having different composition ratio within the same granule with a thermosetting resin at a weight ratio of gel/sol measured by toluene- immersing and extracting method of the terpolymer granules to be (13/87)-(40/60). The latex is obtained by partially polymerizing (A) a monomer mixture comprising 5-15wt.% vinylpyridine, 35-80wt.% styrene and 5-60wt.% butadiene with (B) a monomer mixture comprising 5-20wt.% vinylpyridine, 10-40wt.% styrene and 45-75wt.% butadiene.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive composition, and more particularly to a novel adhesive composition used for adhering a fiber material and rubber.

[0002]

2. Description of the Related Art Conventionally, fibrous materials have been used in the form of filaments, cords, cables, cord fabrics and canvas fabrics for reinforcing rubber articles such as tires, conveyor belts, belts, hoses and air springs.

The bondability between the fibrous material and the rubber is a major factor affecting the product life of the rubber article and various performances of the product.

Therefore, conventionally, in order to obtain a binding force between the fiber material and rubber, an adhesive composition obtained by dissolving or mixing a resin in rubber latex has been used.

Here, examples of the resin include phenol derivative-formaldehyde resin such as resorcin-formaldehyde resin and urea-formaldehyde resin, which have a binding force to the fiber material, and urea-formaldehyde resin. I am using it. Among them, resorcin-formaldehyde resin is most widely used.

As the rubber latex, one or more kinds of vinyl pyridine-styrene-butadiene terpolymer latex, styrene-butadiene copolymer latex, natural rubber latex, etc. may be used in combination. There is. Among them, vinyl pyridine-styrene-
The butadiene terpolymer latex is most widely used, with the main composition being 15% by weight vinyl pyridine, 15% by weight styrene, and 70% by weight butadiene.

As a method of using these adhesives, after applying the adhesive to the fiber material, heat treatment is performed to bond the adhesive and the fiber material, and after that, the fiber material is embedded in the compounded rubber and added. It is common to bond the compounded rubber and the fiber material simultaneously with the vulcanization. The adhesive used in this method is a so-called rubber latex adhesive and is called a rubber vulcanizing adhesive.

[0008]

By the way, in recent years, from the viewpoint of energy saving, tires and the like have been reduced in weight, and the thermal resistance to the reinforcing fiber embedded in rubber and its adhesive has been improved.
Since the dynamic input tends to be larger and more severe, it is desired to improve the strength, modulus and breaking life of various members constituting the product, and at the same time, to improve the adhesive force between the fiber and the rubber.

However, in the conventional vinyl pyridine-styrene-butadiene terpolymer latex, for example, by changing the mixing ratio with the resorcin-formaldehyde resin to firmly bond to the fiber side, a rubber is obtained. There is a disadvantage that the binding force to the fiber side is reduced, and conversely, when the binding force to the rubber side is increased, the binding force to the fiber side is reduced.

Further, in particular, in an adhesive comprising a latex containing vinyl pyridine-styrene-butadiene terpolymer particles and a resorcin-formaldehyde resin,
The effect on thermal stimulation was insufficient.

For example, according to the invention disclosed in Japanese Examined Patent Publication No. 1-49309, the amount of expensive vinylpyridine monomer used is reduced at the same time by making the copolymer particles in the rubber latex have a double structure. The adhesive strength is improved, but in this case, the adhesive strength at high temperature is unsatisfactory.

Further, according to the invention described in JP-A-3-163181, the copolymer particles in the rubber latex are produced by continuous polymerization in two stages, and the first stage and the second stage are constituted. By specifying the composition ratio of the copolymer within a predetermined range, it is attempted to improve the adhesive strength at high temperature.
It cannot be said to be sufficient for the increasingly severe thermal input such as high performance of tires and high temperature vulcanization for improving productivity in recent years.

In view of the above-mentioned conventional inconveniences, the present invention aims to provide an adhesive composition having heat resistance by increasing the adhesive force between a fiber material and rubber and preventing the adhesive force from decreasing at high temperature. And

[0014]

In order to achieve the above object, the present invention has the following arrangement. Vinyl pyridine 5
15% by weight, preferably 7 to 13% by weight, styrene 35
To 80% by weight, preferably 43 to 77% by weight, butadiene 5 to 60% by weight, preferably 10 to 50% by weight, and a vinylpyridine 5 to 20.
% By weight, preferably 7-18% by weight, styrene 10-4
0% by weight, preferably 15-35% by weight, butadiene 4
5 to 75% by weight, preferably 47 to 73% by weight, obtained by division polymerization with the monomer mixture (b).
An adhesive composition comprising a latex containing vinylpyridine-styrene-butadiene terpolymer particles having copolymers having different composition ratios in the same particle and a thermosetting resin, wherein the copolymer particles are Gel / sol weight ratio by toluene dipping extraction method is 13-40 / 87-60, preferably 1
7-33 / 83-67.

The copolymer obtained from the monomer mixture (a) (hereinafter referred to as "copolymer (a)") and the copolymer obtained from the monomer mixture (b) ( Hereinafter, the weight ratio of "copolymer (b)" is 80 to 40/20.
60, preferably 75-45 / 25-55.

The thermosetting resin may be resorcinol.
It is a formaldehyde resin.

Further, the solid content of the thermosetting resin is 8 to 30 parts by weight based on 100 parts by weight of the latex solid content,
It is preferably characterized by blending 12 to 22 parts by weight.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, vinyl pyridine includes 2-vinyl pyridine, 3-vinyl pyridine and 4-vinyl pyridine.
Vinyl pyridine, 2-methyl-5-vinyl pyridine, 5
One or two or more of -ethyl-2-vinylpyridine and the like can be used.

As styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-
Methyl styrene, 2,4-diisopropyl styrene,
2,4-dimethylstyrene, 4-t-butylstyrene,
Among aromatic vinyl compounds such as hydroxymethylstyrene, one kind or two or more kinds can be used.

In addition to 1,3-butadiene, one or more aliphatic conjugated diene-based monomers such as 2-methyl-1,3-butadiene can be used as butadiene.

The copolymer latex of the present invention is polymerized by a known division polymerization method. In the polymerization, known emulsifiers, polymerization initiators, chain transfer agents and the like are used.

As the emulsifier, an alkali metal salt of fatty acid,
Alkali metal salts of rosin acid, formaldehyde-condensed sodium naphthalene sulfonate, sulfuric acid esters of higher alcohols, anionic surfactants such as alkylbenzene sulfonates and aliphatic sulfonates, or alkyl ester type of polyethylene glycol, alkyl ether type,
One or more nonionic surfactants such as alkylphenyl ether type are used.

The amount of the emulsifier used is usually 0.1 to 8 parts by weight, preferably 1 to 100 parts by weight, based on 100 parts by weight of all the monomers.
5 parts by weight.

As the polymerization initiator, a water-soluble initiator such as potassium persulfate, sodium persulfate or ammonium persulfate,
Alternatively, a redox initiator or an oil-soluble initiator such as benzoyl peroxide can be used.

As the chain transfer agent, monofunctional alkyl mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, octyl mercaptan, n-tetradecyl mercaptan, t-hexyl mercaptan and n-hexyl mercaptan, for example, 1,10- Decanedithiol, bifunctional mercaptans such as ethylene glycol dithioglycolate, 1,5,10-canditrithiol,
3 such as trimethylolpropane tristhioglycolate
Functional mercaptans, for example, tetrafunctional mercaptans such as pentaerythritol tetrakisthioglycolate,
Disulfides, for example, carbon tetrachloride, carbon tetrabromide, halogen compounds such as ethylene bromide, α-methylstyrene dimer, terpinolene, α-terpinene, dipentene, allyl alcohol and the like can be used.

These may be used alone or in combination of two or more. The amount of such a molecular weight modifier used is usually 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of all the monomers.

In addition to the above, the latex of the present invention may contain antiaging agents such as styrenated phenols and hindered phenols, silicone-based, higher alcohol-based, mineral oil-based defoaming agents, and other reaction stopping agents, if necessary. You may use additives, such as an agent and an antifreezing agent.

As the thermosetting resin, resorcin-formaldehyde resin, phenol-formaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde resin, phenol derivative-formaldehyde resin, etc., specifically m-3,5- Xylenol-
It is possible to use one or more thermosetting resins such as formaldehyde resin and 5-methylresorcinol-formaldehyde resin which are cured or have a high molecular weight by heating or by applying heat and a methylene donor. it can.

The resin is preferably a resorcin-formaldehyde condensate synthesized under an alkali catalyst, a urea-formaldehyde condensate similarly synthesized under an alkali catalyst, or a resorcin-formaldehyde condensate similarly synthesized under an alkali catalyst. And a phenol derivative-formaldehyde condensate synthesized under acidic or neutral conditions.

The fiber material can be applied to all fiber materials used for reinforcing rubber articles, for example, rayon,
Vinylon, 6-nylon, 6,6-nylon, 4,6-
Examples thereof include aliphatic polyamide fibers such as nylon, aromatic polyamide fibers represented by paraphenylene terephthalamide, polyethylene terephthalate, polyester fibers represented by PEN, and the like.

Further, regarding fiber materials such as aromatic polyamide fibers and polyester fibers, a phenol derivative-formaldehyde resin, an epoxy compound, or, in the fiber polymerization / spinning drawing process or in the post-treatment,
It can be applied after processing with an isocyanate compound or the like, and can also be applied after being previously processed with an electron beam, microwave, plasma treatment or the like.

The form of these fiber materials may be any of cords, cables, filaments, filament chips, cord fabrics, canvas and the like.

The adhesive composition of the present invention can be used by immersing the fibrous material in the liquid of the adhesive composition, applying it with a doctor knife or brush, spraying it with a spray, or spraying it into a powder. Etc., any method may be used, and there is no particular limitation.

Examples of the adhesion processing of the fibrous material include heat treatment at a temperature of 100 to 250 ° C. after application and the like, or processing using electron beams, microwaves, infrared rays or plasma.

Further, examples of articles to which the adhesive composition of the present invention is applied include all rubber articles such as tires, conveyor belts, belts, hoses and air springs.

The operation of the present invention will be described below. The reason why the composition ratios of the copolymer (a) and the copolymer (b) constituting the vinylpyridine-styrene-butadiene copolymer particles in the latex are different is as follows.

That is, the butadiene component which gives a double bond in the particles is mainly used during the vulcanization process and at other high temperatures.
A cross-linking reaction occurs due to a cross-linking agent that migrates and diffuses from the compounded rubber, and as a result of cross-linking, the following effects are exhibited.

First, the cross-linking causes a change in the volume and modulus of the adhesive layer before and after the cross-linking, and the larger the change, the lower the durability of the adhesive force. Since the cross-linking reaction particularly progresses at high temperatures, the adhesion deterioration at high temperatures becomes large.
Therefore, from this point, it is preferable that the butadiene component is small.

Secondly, at the initial stage of vulcanization, the adhesive layer and the adhered rubber are compatibilized by heat, and the particles and the polymer in the rubber are entangled with each other and cross-linked to increase the interfacial bonding force between the adhesive layer and the rubber. obtain. Therefore, from this point, the butadiene component is necessary.

In view of these effects, a vinyl pyridine-styrene-butadiene copolymer latex having a conventional homo-composition structure is widely used with a butadiene content of about 70% by weight.

Homoparticles using the copolymer (a) having a low butadiene content are less affected by changes in volume and modulus due to cross-linking and can be expected to have an effect of improving the durability of the adhesive force. It becomes difficult to mix between the molecular chain of the copolymer in the particle and the adhered rubber polymer due to the compatibilization with
Since the amount of butadiene is small, the amount of cross-linking is small, the interfacial bonding force between the adhesive layer and the rubber is small, and as a result, the adhesion level is low. Compatibilization to
There is an inconvenience that almost no interfacial bonding force is generated and the adhesive is easily broken between the adhesive and the rubber.

Therefore, the present inventors have found that the copolymer (b) having a conventional butadiene content (about 70% by weight) in the same particle is used in order to improve the adhesive strength and prevent the adhesive strength from decreasing at high temperature. And a copolymer (a) having a low butadiene content were formed (see FIG. 1).

That is, the particles obtained by polymerizing by dividing the monomer mixture (a) having a low butadiene content and the monomer mixture (b) having a conventional butadiene content are copolymer particles at the initial stage of vulcanization. And the rubber polymer molecular chain are entangled with each other, and the copolymer (b) in the copolymer particles is co-vulcanized to obtain the same adhesive-rubber interfacial bonding force as in the conventional case, and at the same time, the particles as a whole have butadiene. Since the content is low, when the thermal input is high temperature or long time during vulcanization or product use,
The influence of the change in volume and modulus associated with the crosslinking reaction is reduced, and the adhesive force, especially the heat resistance durability can be improved.

The composition of the copolymer (a) is 5 to 15% by weight of vinyl pyridine, 35 to 80% by weight of styrene, and 5 to 60% by weight of butadiene. The adhesive strength of the entire adhesive layer is reduced, which is not preferable, and when it exceeds 15% by weight, the vulcanization reaction of the latex is accelerated, which is not preferable, and styrene is 35% by weight.
If the amount is less than 80% by weight, the strength of the latex particles is lowered, the strength of the adhesive layer is lowered, and the adhesive strength is lowered.
If it exceeds the above range, the latex particles will be too hard and the flexibility will decrease, and the adhesive strength will decrease significantly when the product is used under high strain, and if the butadiene content is less than 5% by weight, the crosslinking will decrease. The reason is that the adhesive strength is lowered, and if it exceeds 60% by weight, crosslinking of the latex is increased, which is not preferable.

Further, the reason why the composition of the copolymer (b) is 5 to 20% by weight of vinyl pyridine, 10 to 40% by weight of styrene, and 45 to 75% by weight of butadiene is as follows. If the adhesive strength of the entire adhesive layer is reduced, and if it exceeds 20% by weight, the adhesive becomes brittle, which is not preferable, and if styrene is less than 10% by weight, latex particles,
The strength of the adhesive layer is reduced, the adhesive strength is reduced, and
If it exceeds 0% by weight, the co-vulcanizability of the adhesive layer and the adhered rubber will decrease, and the adhesive strength will also decrease, which is not preferable. If it is less than 45% by weight of butadiene, crosslinking will be too small, and if it exceeds 75% by weight, This is because the amount of cross-linking increases and the durability decreases due to changes in volume and modulus.

The order of polymerization of the monomer mixture may be either the monomer mixture (a) or the monomer mixture (b) first. The reason for this is that in the copolymer particles of the present invention, the copolymer in the particles is fluidized by heat during the polymerization, and the copolymer (a) and the copolymer (b) are not heated in one particle. It becomes a mechanically stable two-phase separated structure ("Polymer latex" Soichi Muroi, Ikuo Morino, Shin Polymer Bunko, pages 38-44). Therefore, even if the order of polymerization is reversed, the performance is almost the same.

The reason for setting the gel / sol weight ratio by the toluene immersion extraction method to 13-40 / 87-60 is as follows. That is, the gel content and the sol content in the particles control the adhesive force by the following two actions.

First, the sol component which is not a three-dimensionally dense structure undergoes a crosslinking reaction due to a crosslinking agent that migrates and diffuses from the compounded rubber in the vulcanization step in rubber article processing, and as a result, the adhesive layer Volume and modulus change, adhesive
This is an action of reducing stress by causing stress concentration between the fiber materials and between the adhesive and the rubber.

Secondly, the sol component, which is a fluid component in the particles, causes the polymer molecular chains constituting the particles to be more entangled among the particles in the adhesive layer, whereby the cohesive failure resistance of the strong adhesive layer is increased. With the action of generating a strong interfacial bonding (adhesion) force between the adhesive layer and the rubber interface, the polymer molecular chains constituting the particles in the adhesive layer and the polymer molecular chains in the rubber are more entangled between the adhesive layer and the rubber interface. is there.

The first effect is remarkable when the amount of the crosslinking reaction is large, the temperature is high, and the time is long, and the second effect is that the gel component, which is a non-fluid component, is the strength of the latex particles themselves. It is also necessary to consider that it contributes to the strength of the adhesive composition.

From the above, when the gel content is less than 13% by weight, that is, the sol content exceeds 87% by weight, the volume change and the modulus change of the sol component in the cross-linking reaction become remarkable, and the adhesive-fiber material and the adhesive-rubber Adhesive failure due to stress concentration during the period becomes remarkable, and the gel content of the copolymer particles decreases, so that the strength of the adhesive composition decreases, which is not preferable. On the other hand, when the gel content exceeds 40% by weight, that is, when the sol content is less than 60% by weight, the flowable component decreases, so that the adhesive layer and the adhered rubber become compatible with each other due to the heat of the vulcanization process. During the process, the entanglement of polymer molecular chains between the copolymer particles (particularly the copolymer (b) in the particles) and the rubber is reduced, the adhesive-rubber interfacial bonding force is reduced, and The entanglement of polymer molecular chains also decreases, and the cohesive failure resistance of the adhesive layer decreases, which is not preferable.

The reason that the weight ratio of copolymer (a) / copolymer (b) is 80 to 40/20 to 60 is that when the amount of copolymer (b) is too small, the particles in the adhesive layer are This is because there is less crosslinking between particles and between the particles and the polymer in the rubber, and the adhesive strength is reduced. Further, when the amount of the copolymer (b) is large, the initial adhesive strength is good, but the heat resistance is high. This is because the sex will be impaired and the level will approach the conventional level.

The reason why the mixing ratio of the latex and the thermosetting resin is 8 to 30 parts by weight of the solid content of the thermosetting resin with respect to 100 parts by weight of the solid content of the latex is 8
If it is less than 30 parts by weight, the resulting resin becomes soft and the breaking strength of the adhesive itself is lowered, which is not preferable, and if it exceeds 30 parts by weight, the adhesive becomes hard and brittle and is not suitable for use.

In order to make the copolymer have a structure composed of polymers having different composition ratios, the charging ratio of the monomers constituting the vinyl pyridine-styrene-butadiene terpolymer latex is changed during the polymerization. it can. Specifically, after dissolving an emulsifier such as potassium rosinate in water,
To this, the monomer mixture (a) is added. Further, an electrolyte such as sodium phosphate and peroxides are added as an initiator to carry out polymerization. Then, after reaching a predetermined conversion rate, the monomer mixture (b) is added and the polymerization is continued. Then, after reaching a predetermined conversion rate, a reaction terminator is added to terminate the polymerization, and the residual monomer is removed to obtain a rubber latex having a structure composed of polymers having different composition ratios. .

The polymerization order of the monomer mixture (a) and the monomer mixture (b) may be reversed. Also, gel /
The sol weight ratio can be adjusted by the reaction temperature in the polymerization reaction, the reaction rate, or the type and amount of the chain transfer agent.

The composition of the rubber latex particles produced is as follows:
It can be determined by a method such as a method of determining the polymerization composition ratio from the peak area of the chart by measuring by the NMR (nuclear magnetic resonance) method, or a method of determining the polymerization composition ratio from the loss by measuring the viscoelastic behavior of the polymer. .

Regarding the structure of the particles of the rubber latex produced, the latex particles were dyed with osmium (the double bond site has a dyeing property) and observed by a transmission electron microscope. The structure of two-phase separation due to copolymers with different osmium stains can be observed. A similar particle structure was observed for the copolymer particles in the invention described in JP-A-3-163181.

The gel / sol weight ratio in the rubber latex is
It can be measured by the following method (toluene immersion extraction method).

That is, the sample latex in the state of suspension was poured onto a glass plate so that the film thickness when dried was 0.2 mm, and the sample latex was allowed to stand for 48 hours under constant temperature and humidity of 20 ° C. and 60 RH%. Further, it is left to stand at 40 ° C. under a reduced pressure of 1 Torr or less for 4 hours to prepare a dry film.

Next, this film was subdivided into squares of about 2 mm and weighed (about 0.8 g), and this value was taken as the total weight of the polymer.

200 weighted polymer film
Immersed in ml of toluene, sealed the container and protected from light 40
Leave for 40 hours in a constant temperature bath at ℃. After standing, the polymer / toluene mixed solution is filtered through a 100-mesh wire net, and the filtrate is centrifuged at 3600 rpm (20 ° C.) for 1 hour. After centrifugation, the serum is collected with a 50 ml whole pipette, air-dried at 20 ° C. and a constant temperature and humidity of 60 RH% for 24 hours, and then dried at 120 ° C. under a reduced pressure of 1 torr or less to dry. After drying, the mixture is cooled in a desiccator, and the toluene-soluble content (sol content) is calculated by measuring its weight. From this value and the total weight of the polymer obtained previously, gel /
Calculate the sol weight ratio.

[0062]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. (1) Preparation of resorcin-formaldehyde resin solution A mixture having the composition shown in Table 1 is prepared and aged at room temperature for 8 hours to obtain a resorcin-formaldehyde resin solution.

[0063]

[Table 1] Water 524.01 parts by weight Resorcin 15.12 parts by weight Formalin (37%) 16.72 parts by weight Caustic soda (10%) 11.00 parts by weight

(2) Vinylpyridine-styrene-butadiene
Preparation of ene copolymer latex (i) Preparation of latex used in Comparative Examples 3, 4, 6 and 8 To a nitrogen-substituted autoclave having a volume of 5 liters, 130 parts by weight of deionized water and 4.0 parts by weight of potassium rosinate were added. Charge and dissolve.

The monomer mixture (a) having the composition shown in Tables 4 and 5 and t-dodecyl mercaptan are charged and emulsified. Then, after raising the temperature to 50 ° C., potassium persulfate 0.5
Add parts by weight to initiate polymerization.

The reaction rate of the monomer mixture (a) is 80 to 90.
After reaching 100%, the monomer mixture (b) shown in Tables 4 and 5 and t-dodecyl mercaptan (t-DMP) as a chain transfer agent are added thereto, and the polymerization is further continued.

After the reaction rates shown in Tables 4 and 5 are reached, 0.1 part by weight of hydroquinone is added to terminate the polymerization. Next, the unreacted monomer was removed under reduced pressure to obtain a solid content concentration of 41%.
Obtained a latex. The gel / sol weight ratios of the obtained latex are shown in Tables 4 and 5.

(Ii) Examples 1 to 7 and Comparative Examples 5, 7, 9
Preparation of the latex used in Example 1. Preparation of monomer mixture (a) and t-dodecyl mercaptan composition shown in Tables 4 and 5, and monomer mixture (b) and t-dodecyl mercaptan composition and reaction rate (i) Prepare according to. The gel / sol weight ratio of the latex thus obtained is shown in Tables 4 and 5.

(Iii) Example 8 and Comparative Examples 10 and 11
Preparation of latex used in Example 1 130 parts by weight of deionized water and 4.0 parts by weight of potassium rosinate were charged and dissolved in a 5 liter capacity autoclave purged with nitrogen.

The monomer mixture (b) having the composition shown in Tables 4 and 5 and t-dodecyl mercaptan are charged and emulsified. Then, after raising the temperature to 50 ° C., potassium persulfate 0.5
Add parts by weight to initiate polymerization.

The reaction rate of the monomer mixture (b) is 80 to 90.
%, The monomer mixture (a) shown in Tables 4 and 5 and t-dodecyl mercaptan are added thereto, and the polymerization is further continued.

After reaching the reaction rates shown in Tables 4 and 5, 0.1 part by weight of hydroquinone is added to terminate the polymerization.

Next, the unreacted monomer was removed under reduced pressure to obtain a copolymer latex. The gel / sol weight ratios of the obtained latex are shown in Tables 4 and 5.

(Iv) Preparation of Latex Used in Comparative Examples 1, 2 and X Prepared according to the preparation method of (i) in terms of monomer mixture and t-dodecyl mercaptan composition and reaction rate shown in Tables 4 and 5. .
The gel / sol weight ratio of the latex thus obtained is shown in Tables 4 and 5.

(V) Preparation of Latex Used in Comparative Example Y 40 parts by weight of the latex liquid of Comparative Example 1 prepared in (iii) and 60 parts by weight of the latex of Comparative Example 2 are mixed.

(3) Preparation of Adhesive Composition The latex 4 prepared in (2) was added to 566.85 parts by weight of the resorcin-formaldehyde resin solution prepared in (1).
After adding 33.15 parts by weight, it was aged at room temperature for 16 hours to obtain an adhesive composition.

(4) Fabrication of cord As a fiber material, poly (1,4-phenylene terephthalamide) [trade name: Kevlar, manufactured by DuPont] 150
The 0d raw yarn was twisted 32 times / 10 cm and the two twisted yarns were further twisted 32 times / 10 cm to produce a cord.

(5) Pretreatment of cord The cord obtained in (4) is immersed in an aqueous solution of an epoxy compound shown in Table 2 below, dried at 160 ° C. for 60 seconds, and further 24
A heat treatment was performed at 0 ° C. for 60 seconds to prepare a pretreatment cord.

[0079]

[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

(6) Adhesive Composition Treatment of Pretreated Cord The cord obtained in (5) is immersed in the adhesive composition obtained in (3), dried at 160 ° C. for 60 seconds, and further at 240 ° C. 60
The adhesive composition treatment cord was produced by heat treatment for 2 seconds.

(7-1) Vulcanization I The adhesive composition treatment code obtained in (6) was embedded in an unvulcanized rubber composition having the composition shown in Table 3, and 170 ° C. × 30
Vulcanize under a pressure of 20 kg per minute and square centimeter.

(8-1) Measurement of initial adhesive strength A cord was dug up from the vulcanized product obtained in (7-1),
The drag force when the cord was peeled from the vulcanized product was measured at a speed of cm / min, and this was taken as the initial adhesive force. The results are shown in Tables 4 and 5.

(7-2) Vulcanization II The adhesive composition treatment cord obtained in (6) was embedded in an unvulcanized rubber composition having the composition shown in Table 3, and 190 ° C. × 30
Vulcanize under a pressure of 20 kg per minute and square centimeter.

(8-2) Measurement of heat-resistant adhesive strength A cord was dug up from the vulcanized product obtained in (7-2), and the cord was peeled from the vulcanized product at a speed of 30 cm / min in the same manner as above. The drag was measured and this was taken as the heat resistant adhesive strength. The results are shown in Tables 5 and 6.

(8-3) Measurement of adhesive strength after heat aging The vulcanized product obtained in (7-1) was enclosed in a glass tube substituted with nitrogen, and left in a heat oven at 125 ° C. for 5 days, and then, initially. The peel resistance was measured by the same method as the adhesive strength, and this was taken as the adhesive strength after heat aging. The results are shown in Tables 4 and 5.

[0086]

Table 3 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 Baintar 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

[0087]

[Table 4]

[0088]

[Table 5]

From the measurement results of Tables 4 and 5, Examples 1 to 5 were obtained.
Comparative Examples 3, 4, and 6 in which the gel / sol weight ratio is outside the specified range
Compared with, the initial adhesive strength is equal or higher,
It can be seen that the heat resistant adhesive strength was remarkably high, and the decrease in adhesive strength at high temperatures could be significantly suppressed. Similarly, Example 6 is compared with Comparative Examples 6 and 7, Example 7 is compared with Comparative Examples 8 and 9,
It can be seen that the heat resistance is improved.

Further, Example 8 has the same polymer composition ratio as Examples 1 to 5, but the order of polymerizing the monomer mixture (a) and the monomer mixture (b) is reversed. It can be seen that in Example 8, the initial adhesive strength was equal to or higher than in Comparative Examples 10 and 11, and the heat resistance was improved.

In Comparative Examples 1, 2, X, and Y, the gel / sol weight ratio is within the specified range, but has a homo structure. Comparative Example 1 is a copolymer (b) whose polymer composition ratio is Comparative Example 3 or the like.
Comparative Example 2 has a polymer composition ratio equal to that of the copolymer (a) of Comparative Example 3 and the like, and Comparative Example X has a polymer composition ratio of the whole particles of Comparative Examples 3 and 10 and the like. Equal to the composition of. Comparative Example Y is a mixture of Comparative Example 1 whose polymer composition ratio is the same as that of the copolymer (b) and Comparative Example 2 whose polymer composition ratio is the same as that of the copolymer (a). The mixing ratio is the copolymer (a) / copolymer (b) of Comparative Example 3 or the like.
Equal to weight ratio.

The initial adhesive strength and heat resistant adhesive strength of these are inferior to those of the examples, and the structure has not only the gel / sol weight ratio but also the copolymer having different composition ratios in the same particle. It turns out that is also required. Also,
It can be seen that sufficient adhesive force is maintained in comparison with conventional products against heat generated by rubber during use in rubber products such as tires and conveyor belts.

Further, Comparative Examples 1, 2, X and Y are inferior to the other Comparative Examples having a structure having copolymers having different composition ratios in the same particle, and therefore the same as the above can be said. .

[0094]

EFFECTS OF THE INVENTION The adhesive composition of the present invention has a further improved adhesive strength, and further has a small decrease in adhesive strength even at high temperatures, and has heat resistance and durability.

[Brief description of drawings]

FIG. 1 is an example of an electron micrograph of a latex obtained by division polymerization, which was dyed with osmium and observed with a transmission electron microscope. The composition is as follows: monomer mixture (a): butadiene / styrene / vinyl pyridine = 2
7.5 / 60 / 12.5, monomer mixture (b): butadiene / styrene / vinyl pyridine = 70/15/15.

FIG. 2 is an electron micrograph similar to FIG. 1, except for the magnification.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kozo Sasaki 3-3-6-509 Ogawa Higashicho, Kodaira-shi, Tokyo (72) Inventor Masaaki Tsuji 536-122 Minamikasa-cho, Kusatsu-shi, Shiga (72) Inventor Kazuo Ojima 1071-99 Fueda, Kamakura City, Kanagawa Prefecture

Claims (4)

[Claims] 1. A monomer mixture (a) composed of 5 to 15% by weight of vinylpyridine, 35 to 80% by weight of styrene, and 5 to 60% by weight of butadiene, and 5 to 20% of vinylpyridine.
% By weight, 10 to 40% by weight of styrene, 45 to butadiene
Includes vinylpyridine-styrene-butadiene terpolymer particles having copolymers having different composition ratios in the same particle, which are obtained by division polymerization with a monomer mixture (b) composed of 75% by weight. An adhesive composition comprising a latex and a thermosetting resin, wherein the copolymer particles have a gel / sol weight ratio of 13 to 40/87 by a toluene immersion extraction method.
The adhesive composition is 60. 2. The weight ratio of the copolymer obtained from the monomer mixture (a) and the copolymer obtained from the monomer mixture (b) is 80 to 40/20 to 60. The adhesive composition according to claim 1, wherein: 3. The adhesive composition according to claim 1, wherein the thermosetting resin is a resorcin-formaldehyde resin. 4. The adhesive composition according to claim 1, wherein the solid content of the thermosetting resin is 8 to 30 parts by weight based on 100 parts by weight of the solid content of the latex. .