JP6008680B2 - Adhesive composition and tire cord using the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an adhesive composition and a tire cord using the same (hereinafter, also simply referred to as “cord”). Specifically, a tire cord excellent in adhesion fatigue resistance and heat-resistant adhesion in rubber can be obtained. The present invention relates to an adhesive composition suitable for one bath treatment and a tire cord using the same.

  Conventionally, as an adhesive treatment for inactive tire cords such as polyester and aramid, a two-bath treatment in which pretreatment is performed with epoxy or the like and then immersed in resorcin / formaldehyde / latex (RFL) is generally used. Has been used. However, although the two-bath treatment can provide a sufficient adhesive force, the overall cost tends to be higher due to an increase in processing costs due to the two-bath treatment and restrictions on facilities, and a one-bath treatment is desired.

  On the other hand, in the one-bath treatment, since it is difficult to ensure adhesiveness only with RFL, one-bath treatment with an adhesive solution in which a modified phenol resin is mixed with an RFL solution has been proposed (for example, Patent Document 1). In addition, a one-bath treatment in which a reactive reagent such as an epoxy or a blocked isocyanate compound is previously mixed with the RFL solution has been proposed (for example, Patent Documents 2 and 3). Further, Patent Document 4 also proposes an adhesive composition using a vinylpyridine / styrene / butadiene copolymer that is divided and polymerized as a latex (for example, Patent Document 4).

Japanese Patent Publication No. 48-8733 Japanese Patent No. 3280826 JP-A-10-204780 Japanese Patent No. 3559114

  However, as disclosed in Patent Document 1, in the method using a modified phenol resin by the method of one bath treatment, the adhesive strength at high temperature tends to decrease due to the thermoplasticity of the resin. In addition, as in Patent Documents 2 and 3, the method of mixing an epoxy or a blocked isocyanate compound in one bath can provide adhesive strength, but the adhesive resin becomes hard and the adhesion fatigue property deteriorates. is there. For this reason, the present situation is that it is not necessarily suitable for tire use because, for example, sufficient heat-resistant adhesiveness in rubber necessary for tire cords cannot be ensured. Further, when the adhesive resin is hard, the tire cord becomes hard, so that there is a problem that handling property and workability at the time of tire manufacture are deteriorated.

  Heat resistant adhesiveness in rubber can be ensured by increasing the amount of adhesive resin applied to the cord, but in this case, the adhesion fatigue properties will be deteriorated. On the other hand, for example, a vinyl chloride resin has been proposed as a chemical for ensuring heat-resistant adhesion in rubber without increasing the amount of adhesive resin. However, vinyl chloride resin is not preferable for safety, and the present situation is that sufficient technology has not been established. Even in an adhesive composition using a split-polymerized vinylpyridine / styrene / butadiene copolymer proposed in Patent Document 4, it is necessary to increase the thermosetting resin in order to improve the adhesiveness. However, if the thermosetting resin is increased beyond a certain level, the adhesive becomes hard and brittle, and sufficient adhesiveness cannot be obtained.

  Accordingly, an object of the present invention is to provide an adhesive composition suitable for a one-bath treatment and a tire cord using the same, which can obtain a cord for tire excellent in adhesion fatigue resistance and heat-resistant adhesion in rubber. There is.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor can ensure heat-resistant adhesiveness in rubber by optimizing the cross-linking reaction using a latex having a core with a small amount of butadiene component. The inventors have found that it is possible to ensure flexibility of the adhesive composition and achieve both fatigue and heat-resistant adhesive force while sufficiently blending an isocyanate compound necessary for adhesion, and have completed the present invention.

That is, the adhesive composition of the present invention is an adhesive composition having a vinylpyridine / styrene / butadiene copolymer latex and a thermosetting resin containing a blocked isocyanate compound.
Mixed solution in which the vinylpyridine / styrene / butadiene copolymer latex is contained in an amount of 5 to 15% by mass, 35 to 80% by mass and 5 to 60% by mass with respect to the total of vinylpyridine, styrene and butadiene, respectively. The polymerization is started at, and the polymerization is terminated by changing the input amount of each component in three or more stages until each component becomes 5 to 20% by mass, 10 to 40% by mass and 45 to 75% by mass, respectively. In addition, a vinylpyridine / styrene / butadiene copolymer latex having a core portion and a shell portion, wherein the composition of each component of the core portion and the shell portion changes gently. Yes, and
The solid content of the thermosetting resin containing the blocked isocyanate compound is 35 to 100 parts by mass with respect to 100 parts by mass of the solid content of the vinylpyridine / styrene / butadiene copolymer latex. .

  In this invention, the said vinylpyridine * styrene * butadiene copolymer latex is 5-15 mass%, 35-80 mass%, and 5-60 mass respectively with respect to the sum total of vinylpyridine, styrene, and a butadiene. Polymerization is started by changing the amount of each component in 3 to 5 steps until each component becomes 5 to 20% by mass, 10 to 40% by mass and 45 to 75% by mass, respectively. Is preferably a vinylpyridine / styrene / butadiene copolymer latex obtained by terminating the process. In the present invention, the thermosetting resin preferably includes a resorcin-formaldehyde resin using ammonia as a catalyst, and the ammonia is preferably in the range of 0.5 to 5.0 mol with respect to 1 mol of the resorcin. .

  The tire cord of the present invention is characterized in that an adhesive using the adhesive composition of the present invention is applied to an organic fiber cord and dried.

  In the present invention, the organic fiber cord is preferably a polyester cord or an aramid cord.

  ADVANTAGE OF THE INVENTION According to this invention, the cord for tires excellent in adhesion fatigue property and heat resistant adhesiveness in rubber | gum can be obtained, and the cord for tires using the adhesive composition suitable for 1 bath process and it are provided. it can.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The adhesive composition of the present invention is an adhesive composition having a vinylpyridine / styrene / butadiene copolymer latex and a thermosetting resin containing a blocked isocyanate compound. In the present invention, the vinylpyridine / styrene / butadiene copolymer latex is 5 to 15% by mass of vinylpyridine, 35 to 80% by mass of styrene, and butadiene with respect to the total of vinylpyridine, styrene and butadiene. Polymerization is started with a mixed solution containing 5 to 60% by mass, and each component is in three or more stages or continuously until each component becomes 5 to 20% by mass, 10 to 40% by mass and 45 to 75% by mass, respectively. This is a vinylpyridine / styrene / butadiene copolymer latex obtained by changing the input amount to terminate the polymerization. The solid content of 100 parts by mass of the vinylpyridine / styrene / butadiene copolymer latex is blocked. It is important to contain 35 to 100 parts by mass of a thermosetting resin containing an isocyanate compound in solid content.

  First, the vinylpyridine / styrene / butadiene copolymer latex will be described. The reason why the composition of the vinylpyridine / styrene / butadiene copolymer latex is changed at the start of the reaction and at the end of the reaction is as follows. That is, the butadiene component that gives double bonds in the latex particles causes a cross-linking reaction by a cross-linking agent that migrates and diffuses from the compounded rubber mainly during the vulcanization process and when used at other high temperatures. Shows the effect. First, due to cross-linking, the volume and modulus of the adhesive layer change before and after cross-linking, and the greater the change, the more the durability of the adhesive strength is impaired. Since the cross-linking reaction proceeds particularly at high temperatures, adhesion deterioration at high temperatures is increased. Therefore, from this point, it is preferable that the butadiene component is small. Secondly, in the initial stage of vulcanization, the adhesive layer and the rubber to be adhered are made compatible by heat, and the particles and the polymer in the rubber are entangled and crosslinked to obtain an interface bonding force between the adhesive layer and the rubber. Therefore, from this point, a butadiene component is required.

  In view of these actions, conventional vinyl pyridine / styrene / butadiene copolymer latexes having a homo-composition structure are widely used having a butadiene content of about 70% by mass. Homo particles using a copolymer with a low butadiene content are less affected by changes in volume and modulus due to cross-linking, and can be expected to improve the durability of adhesive strength. It becomes difficult to mix between the molecular chain of the copolymer and the rubber polymer to be adhered, and since the amount of butadiene is small, the cross-linking is reduced and the interfacial bonding force between the adhesive layer and the rubber is small. In particular, when the butadiene content is 40% or less, the compatibilization of the particles with the adherend rubber is remarkably reduced, and there is almost no interfacial bonding force, which easily causes adhesive failure between the adhesive and the rubber. There is an inconvenience.

  Therefore, in the present invention, in order to improve the adhesive strength and prevent the adhesive strength from being lowered at high temperatures, the same particle has a shell portion having a conventional butadiene content and a core portion having a low butadiene content, and each component is The structure changes gently. In other words, a vinylpyridine / styrene / butadiene copolymer latex in which the butadiene content is gently inclined in the core portion having a low butadiene content and the shell portion having a butadiene content at a conventional level is formed into a copolymer at the initial stage of vulcanization. By entanglement of latex and rubber polymer molecular chains and co-vulcanization of the shell part, the same adhesive-rubber interface bonding force as before can be obtained. At the same time, since the butadiene content in the whole particle is reduced, when the thermal input becomes high or long, such as during vulcanization or product use, the influence of volume and modulus changes associated with the crosslinking reaction is reduced. In particular, the heat durability can be improved. Preferably, each component is divided into 3 to 5 stages, and the amount of each component is changed so as to increase the butadiene content, and the vinylpyridine / styrene / butadiene copolymer latex is polymerized.

  The reason why the composition at the start of the reaction is 5 to 15% by mass of vinylpyridine, 35 to 80% by mass of styrene, and 5 to 60% by mass of butadiene is as follows. If the amount of vinylpyridine is less than 5% by mass, the adhesive strength of the entire adhesive layer is reduced. On the other hand, if it exceeds 15% by mass, the vulcanization reaction of the latex is accelerated. If styrene is less than 35% by mass, the strength of the latex particles decreases, leading to a decrease in the strength of the adhesive layer, and thus a decrease in adhesive strength. On the other hand, if it exceeds 80% by mass, the latex particles become too hard and flexible. Decreases, and when the product is used under high strain, the adhesive strength is drastically reduced. If the butadiene content is less than 5% by mass, the crosslinking is reduced and the adhesive strength is lowered. On the other hand, if the content exceeds 60% by mass, the latex is frequently crosslinked.

  The reason for the composition at the end of the reaction being 5-20% by mass of vinylpyridine, 10-40% by mass of styrene, and 45-75% by mass of butadiene is as follows. If the amount of vinylpyridine is less than 5% by mass, the adhesive strength of the entire adhesive layer is reduced. On the other hand, if it exceeds 20% by mass, the adhesive becomes brittle. When the styrene is less than 10% by mass, the strength of the latex particles and the adhesive layer is reduced, and the adhesive strength is reduced. When the styrene exceeds 40% by mass, the co-vulcanizability between the adhesive layer and the adherend rubber is reduced, Again, the adhesive strength is reduced. If the butadiene is less than 45% by mass, the amount of crosslinking is too small, and if it exceeds 75% by mass, the number of crosslinking increases, resulting in a decrease in durability due to volume and modulus changes.

  In addition, the composition of the core and shell is changed by changing the composition of raw materials at the time of polymerization at three or more stages or continuously, so that the thermal input is high during vulcanization and product use. Or when it becomes long time, the influence by the volume and modulus change accompanying a crosslinking reaction decreases, and it can improve adhesive force, especially heat-resistant durability. Since the effect of improving the heat resistant adhesion in rubber is low when the change in the ingredients of the raw material is two stages, sufficient heat resistant adhesive strength in rubber cannot be obtained by a method of mixing an epoxy or blocked isocyanate compound in one bath.

  In order to obtain the effect of the present invention satisfactorily, the polymerization is started with 7 to 13% by mass of vinylpyridine, 43 to 77% by mass of styrene and 10 to 50% by mass of butadiene, and 7 or more stages of vinylpyridine are continuously added. A vinylpyridine / styrene / butadiene copolymer latex is synthesized by changing ˜18 mass%, styrene 15 to 35 mass% and butadiene to 47 to 73 mass%.

  The vinylpyridine / styrene / butadiene copolymer according to the present invention can be produced as follows. For example, after dissolving an emulsifier such as potassium rosinate in water, 5-15% by mass, 35-80% by mass, and 5-60% by mass with respect to the total of vinylpyridine, styrene, and butadiene, respectively. Each component is added so that it is contained in a percentage. Further, an electrolyte such as sodium phosphate and peroxides are added as an initiator to perform polymerization. Thereafter, after reaching the predetermined conversion rate, the polymerization is continued by changing the vinyl pyridine to 5 to 20% by mass, styrene to 10 to 40% by mass and butadiene to 45 to 75% by mass in three or more stages or continuously. . Thereafter, after reaching a predetermined conversion rate, a reaction terminator is added to stop the polymerization, and further, by removing the remaining monomer, vinyl pyridine styrene styrene having a structure composed of polymers having different composition ratios is obtained. A butadiene copolymer can be obtained.

  Next, the thermosetting resin will be described. The thermosetting resin according to the present invention contains a blocked isocyanate compound. Such a thermosetting resin is indispensable for enhancing the adhesiveness. However, when the addition amount is increased, the adhesive layer becomes hard and brittle, and sufficient adhesiveness cannot be obtained. However, in the case of the vinylpyridine / styrene / butadiene copolymer latex according to the present invention, 35 to 100 parts by mass of a thermosetting resin containing a blocked isocyanate compound, preferably 50 to 80 parts by mass, Excessive curing of the adhesive layer can be suppressed. Thereby, even if it is 1 bath processing, adhesion fatigue property and heat-resistant adhesiveness are securable.

  The reason why the addition amount of the thermosetting resin containing the blocked isocyanate compound is 35 to 100 parts by mass with respect to 100 parts by mass of the solid content of the vinylpyridine / styrene / butadiene copolymer latex is as follows. It is. That is, when the amount of the thermosetting resin containing the blocked isocyanate compound is less than 35 parts by mass, sufficient adhesive force cannot be given to the organic fiber cord, while when it exceeds 100 parts by mass, the adhesiveness is Although it can be obtained sufficiently, the adhesive resin becomes hard, the fatigue property of the tire cord cannot be ensured, and the cost is not preferable. In addition, in order to acquire the said effect fully, it is preferable that content of the blocked isocyanate compound with respect to a thermosetting resin shall be 50-80 mass%.

  In the present invention, 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- Use one or more thermosetting resins such as xylenol-formaldehyde resin, 5-methylresorcinol-formaldehyde resin, etc. that cure or become high molecular weight by heating or giving methylene donor. Can do.

  Such resins are preferably acidic or resorcin-formaldehyde condensates synthesized under alkaline catalysts, urea-formaldehyde condensates also synthesized under alkaline catalysts, or resorcin-formaldehyde condensates also synthesized under alkaline catalysts. It is a mixture of a phenol derivative and a formaldehyde condensate synthesized under neutrality.

  In the present invention, the blocked isocyanate compound is preferably an organic polyisocyanate compound such as diphenylmethane diisocyanate (MDI) or tolylene diisocyanate (TDI) blocked with a blocking agent. Examples of the blocking agent include phenols such as phenol, thiophenol, chlorophenol, cresol, resorcinol, p-sec-butylphenol, p-tert-butylphenol, p-sec-amylphenol, p-octylphenol, p-nonylphenol; Secondary or tertiary alcohols such as isopropyl alcohol and tert-butyl alcohol; aromatic secondary amines such as diphenylamine; phthalimides; lactams such as δ-valerolactam; caprolactams such as ε-caprolactam Active methylene compounds such as malonic acid dialkyl ester, acetylacetone and acetoacetic acid alkyl ester; ketoximes such as acetoxime, methylethylketoxime and cyclohexanone oxime; 3-hydroxy Basic nitrogen compounds such as pyridine and acidic sodium sulfite can be raised. Phenol, ε-caprolactam and ketoxime are preferred as the blocking agent.

  In the present invention, the thermosetting resin preferably contains a resorcin-formaldehyde resin using ammonia as a catalyst, and the ammonia is preferably in the range of 0.5 to 5.0 mol with respect to 1 mol of resorcin. If the amount of ammonia is less than 0.5 mol with respect to 1.0 mol of resorcin, the effect as a resorcin resin catalyst is not sufficient, the aging reaction takes time, the aging reaction does not proceed sufficiently, and adhesion cannot be secured. There is a case. Moreover, since there is little quantity of ammonia resole, there exists a possibility that RFL liquid may harden | cure. On the other hand, when the amount exceeds 5.0 mol, the reaction system is promoted, so that the flexibility of the RFL solution may be impaired.

  Furthermore, ammonia is used as a catalyst for the condensation reaction between resorcin and formaldehyde without using a metal catalyst such as sodium hydroxide, because a metal compound catalyst such as sodium hydroxide promotes curing of the RFL solution. This is because it is not suitable for ensuring the flexibility of the RFL solution. Moreover, since the metal compound catalyst is strongly basic, it is easy to promote deterioration of rubber and cord. On the other hand, since ammonia is weakly basic, the curing reaction proceeds at an appropriate rate. Thereby, the flexibility of the RFL liquid can be maintained. Moreover, since ammonia can be desorbed from the system by vaporizing from the ammonia resol type resin, physical softening and rubber deterioration due to base can be suppressed.

  The adhesive composition of the present invention is excellent in adhesiveness between the organic fiber cord and the rubber, and is suitable as an adhesive for a tire cord. When manufacturing the cord for tires using the adhesive composition of the present invention, it is manufactured by drying the organic fiber cord coated with the adhesive, and this drying temperature is usually 180 ° C to 210 ° C. . By setting the drying temperature and the blocking agent dissociation temperature of the blocked isocyanate to be approximately the same, the network density of the thermosetting resin can be reduced, and the flexibility of the adhesive resin composition can be ensured. Therefore, in the adhesive composition of the present invention, it is preferable to use a blocked isocyanate compound having a blocking agent separation temperature of 180 to 210 ° C.

  In the adhesive composition of the present invention, the thermosetting resin containing a blocked isocyanate compound is 35 to 100 mass in terms of solid content with respect to 100 mass parts of the vinylpyridine / styrene / butadiene copolymer latex synthesized under the above conditions. It is important to contain only part, and there are no particular restrictions on the rest. Examples of vinyl pyridine include 2-vinyl pyridine, 3-vinyl pyridine, 4-vinyl pyridine, 2-methyl-5-vinyl pyridine, 5-ethyl-2-vinyl pyridine, etc. Species or two or more can be used.

  As styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, hydroxymethylstyrene An aromatic vinyl compound such as, for example, can be used, and one or more of these can be used.

  In addition to 1,3-butadiene, butadiene can include one or more aliphatic conjugated diene monomers such as 2-methyl-1,3-butadiene, one of which Or 2 or more types can be used.

  Furthermore, in the polymerization of the copolymer latex of the present invention, known emulsifiers, polymerization initiators, chain transfer agents and the like may be used. In addition to the above, the copolymer latex of the present invention may be used in addition to the above-mentioned anti-aging agents such as styrenated phenols and hindered phenols, silicone-based, higher alcohol-based, mineral oil-based antifoaming agents, and other reaction terminations. Additives such as agents and antifreeze agents may be used.

  As an emulsifier, an anionic surfactant such as an alkali metal salt of a fatty acid, an alkali metal salt of rosin acid, sodium formaldehyde condensed naphthalene sulfonate, a higher alcohol sulfate, an alkylbenzene sulfonate, an aliphatic sulfonate, or polyethylene glycol One type or two or more types of nonionic surfactants such as alkyl ester type, alkyl ether type and alkylphenyl ether type can be used. The usage-amount of such an emulsifier is 0.1-8 mass parts normally with respect to 100 mass parts of all monomers, Preferably it is 1-5 mass parts.

  As the polymerization initiator, water-soluble initiators such as potassium persulfate, sodium persulfate, and ammonium persulfate, redox initiators, and oil-soluble initiators 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, n-hexyl mercaptan, for example, 1,10-decandithiol, Bifunctional mercaptans such as ethylene glycol dithioglycolate, trifunctional mercaptans such as 1,5,10-canditrithiol and trimethylolpropane tristhioglycolate, for example, tetrafunctional mercaptans such as pentaerythritol tetrakisthioglycolate , Disulfides such as halogen compounds such as carbon tetrachloride, carbon tetrabromide and ethylene bromide, α-methylstyrene dimer, terpinolene, α-terpinene, dipentene, allyl alcohol, etc. These may be used alone or in combination of two or more. The usage-amount of such a molecular weight modifier is 0.01-5 mass parts normally with respect to 100 mass parts of all monomers, and is 0.1-3 mass parts suitably.

Next, the tire cord of the present invention will be described.
The tire cord of the present invention is a tire cord formed by drying an organic fiber cord coated with an adhesive using the adhesive composition of the present invention. By using the adhesive composition of the present invention, a tire cord having adhesion fatigue resistance and heat-resistant adhesion in rubber can be obtained even in one bath treatment. In the tire cord of the present invention, the adhesive is preferably dried at 180 to 210 ° C. As mentioned above, by making the drying temperature of the cord and the blocking agent dissociation temperature of the blocked isocyanate about the same, the network density of the thermosetting resin is lowered, and further the flexibility of the adhesive composition is secured. Because you can. Other conditions such as cord tension at the time of drying can be appropriately selected according to a known method.

  In the present invention, the material of the organic fiber cord is not particularly limited, and is made of cotton, rayon, polyamide (nylon-6, nylon-6, 6, etc.), polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), aramid (m- (Phenylene isophthalamide, p-phenylene terephthalamide, etc.) can be mentioned, and the cord for tire is preferably a cord of polyester or polyamide. Further, according to a known method, a cord subjected to surface activation treatment such as corona treatment, plasma treatment or epoxy treatment can also be used.

  The tire cord of the present invention is preferably baked at 210 to 250 ° C. after drying. As a result, the blocking agent of the blocked isocyanate compound can be separated in the adhesive composition, and the reaction between the thermosetting resin and the tire cord can be sufficiently advanced, and good adhesion fatigue and heat resistant adhesiveness can be achieved. Can be obtained. The other conditions such as the tension of the cord during baking can be appropriately selected according to a known method.

  For the tire cord of the present invention, it is only important to use an adhesive liquid using the above-described adhesive composition of the present invention, and otherwise there is no particular limitation, and a known method can be used. For example, in applying the adhesive, means such as dipping, brushing, casting, spraying, roll coating, knife coating and the like can be mentioned. Other conditions such as cord tension when applying the adhesive can be selected as appropriate according to a known method.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Examples 1-10 and Comparative Examples 1-3)
Cords made of the materials shown in Tables 1 and 2 below were prepared. Next, the adhesive compositions of Examples 1 to 10 and Comparative Examples 1 to 3 were prepared with the formulation shown in the same table, and while maintaining the blending ratio of this adhesive composition shown in the same table, 20% by mass An adhesive aqueous solution was prepared. As the blocked isocyanate compound, Elastrone BN69 (blocking agent separation temperature 120 ° C.) and BN27 (blocking agent separation temperature 180 ° C.) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. were used. These blocked isocyanate compounds were blended with an RFL adhesive solution and aged at 20 ° C. for 24 hours, and then added immediately before use. A latex copolymer was prepared by emulsion polymerization.

  In the table, the first step in the column of composition change during polymerization means that the amount of each component is constant from the start of polymerization to the end of polymerization, and the second step means that the polymerization time is divided into two equal parts, Meaning that the input amount of each component was switched over time, and the third stage means that the polymerization time was divided into three equal parts, and the input amount of each component at the start and end of polymerization was set to an intermediate value in the second stage. In the fifth stage, the polymerization time is divided into five equal parts, the third stage is an intermediate value of the amount of each component at the start and end of the polymerization, and the second stage and the fourth stage are further 3 It means that it was set to the middle value of the stage.

  Tire cords were produced using the obtained adhesive liquids and organic fiber cords. The drying temperature was the temperature shown in Tables 1 and 2, and the drying time was 2 minutes. Thereafter, baking treatment was performed at the temperature shown in the table. The baking time was 1 minute and the cord tension was 1 kg / piece.

  Using each organic fiber cord obtained by the above procedure as a carcass ply material, a tire having a tire size of 225 / 45R17 having two layers of carcass plies was produced.

<New tire peeling resistance>
For each of the obtained tires, the adhesive force between the first-layer carcass ply and the second-layer carcass ply was measured, and this was taken as the peel resistance. The adhesive force was performed according to JIS K 6854-2 (1999). The results obtained are also shown in Tables 1 and 2.

<Drum running tire peeling resistance>
Each tire obtained was run on a drum at a speed of 60 km / h for 20,000 km under the maximum load condition of JATMA, and then the adhesion between the first carcass ply and the second carcass ply was measured. This was taken as the peel resistance. The adhesive force was performed according to JIS K 6854-2 (1999). The results obtained are also shown in Tables 1 and 2.

<Failure after running the drum>
After the drum test, it was investigated whether or not a failure occurred. The results obtained are also shown in Tables 1 and 2.

  From Tables 1 and 2, it can be seen that according to the adhesive composition of the present invention, a tire cord having adhesion fatigue resistance and heat-resistant adhesion in rubber can be produced by one bath treatment. In Comparative Example 1, both the new tire peel strength and the drum running tire peel strength were improved, but since the vinylpyridine / styrene / butadiene copolymer latex was polymerized in two stages, The composition difference between the composition and the composition at the end of polymerization is large. Therefore, when heat is generated as in high-speed running in drum running, adhesion deterioration is likely to occur, resulting in failure.

Claims (5)

In an adhesive composition having a vinylpyridine / styrene / butadiene copolymer latex and a thermosetting resin containing a blocked isocyanate compound,
Mixed solution in which the vinylpyridine / styrene / butadiene copolymer latex is contained in an amount of 5 to 15% by mass, 35 to 80% by mass and 5 to 60% by mass with respect to the total of vinylpyridine, styrene and butadiene, respectively. in the polymerization starts, 5-20 wt% components, respectively, 10 to 40% by weight and until 45 to 75% by weight on three stages or more by changing the charged amount of each component to terminate the polymerization to give A vinylpyridine / styrene / butadiene copolymer latex having a core part and a shell part, wherein the composition of each component of the core part and the shell part changes gently. And
An adhesive composition comprising 35 to 100 parts by mass of a solid content of a thermosetting resin containing the blocked isocyanate compound with respect to 100 parts by mass of the solid content of the vinylpyridine / styrene / butadiene copolymer latex. object.   Mixed solution in which the vinylpyridine / styrene / butadiene copolymer latex is contained in an amount of 5 to 15% by mass, 35 to 80% by mass and 5 to 60% by mass with respect to the total of vinylpyridine, styrene and butadiene, respectively. Polymerization is started, and the amount of each component is changed in 3 to 5 steps until the respective components become 5 to 20% by mass, 10 to 40% by mass and 45 to 75% by mass, respectively, and the polymerization is terminated. 2. The adhesive composition according to claim 1, wherein the latex is a vinyl pyridine / styrene / butadiene copolymer latex.   The adhesive composition according to claim 1 or 2, wherein the thermosetting resin contains a resorcin-formaldehyde resin using ammonia as a catalyst, and the ammonia is in a range of 0.5 to 5.0 mol with respect to 1 mol of the resorcin. object.   A cord for tire, wherein an adhesive using the adhesive composition according to any one of claims 1 to 3 is applied to an organic fiber cord and dried.   The tire cord according to claim 4, wherein the organic fiber cord is a polyester cord or an aramid cord.