JP2512912B2 - Rubber-based composite material manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a rubber-based composite material, in which a substrate such as metal or plastic and a rubber composition are vulcanized and adhered to each other to produce a composite.

2. Description of the Related Art Conventionally, in rubber-based composite materials such as tires and conveyor belts, when a metal is used as a reinforcing base, for example, a steel cord is brass-plated (brass-plated),
A sulfur component, a vulcanization accelerator, and a method of vulcanizing and adhering a rubber composition containing an organic cobalt salt or resorcin-hexamethyltetramine-silica or the like having an effective action for vulcanization adhesion. However, in such a method, it is known that the addition of a sulfur component, an organic cobalt salt, or the like, and the amount used are important factors for stabilizing the adhesion.

For example, when bonding a rubber composition to a substrate such as a brass-plated steel cord, in order to obtain stable adhesion, the amount of sulfur should be at least 4 to 8 parts by weight per 100 parts by weight of the rubber component in the rubber composition. In addition, since an organic cobalt salt such as cobalt naphthenate can stably bond the rubber composition and the substrate, its addition is essential, and usually about 1 to 3 parts should be added. Is being carried out.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, as described above, when a large amount of sulfur of 4 to 8 parts by weight is compounded in the rubber composition, the rubber composition before vulcanization adhesion, that is, the unvulcanized rubber composition, is left for a long time. Sulfur blooms from the rubber composition when left to stand, which poses a serious problem on the preservability of the unvulcanized rubber composition, and the rubber strength of the rubber composition after vulcanization is significantly reduced by heat deterioration. There is a defect that it does.

Further, the use of the organic cobalt salt can control the vulcanization rate appropriately to obtain stable adhesion between the substrate and the rubber composition, but on the other hand, the adhesive strength may deteriorate with time, and the breaking strength and elongation of the rubber may be increased. There is a problem that the tendency such as the degree of deterioration due to heat aging remarkably increases.

Therefore, the compounding amount of the sulfur component (sulfur during sulfur vulcanization or sulfur compound during organic sulfur vulcanization) is reduced, and it has excellent heat aging resistance and stable adhesion to substrates such as metals and plastics. There is a need for a method for producing a rubber-based composite material that can provide good properties, and a method for producing a rubber-based composite material that can provide stable adhesion to a substrate such as metal or plastic even without the addition of an organic cobalt salt. Is required.

The present invention has been made in view of the above circumstances, it is possible to reduce the amount of the sulfur component required for vulcanization adhesion of the rubber composition,
Further, an object of the present invention is to provide a method for producing a rubber-based composite material having excellent heat aging resistance, high bonding strength, and stable adhesiveness over a long period of time without using any organic cobalt salt. .

Means and Actions for Solving Problems The present inventors have conducted extensive studies on a method for joining a substrate and a rubber composition in order to achieve the above object, and as a result, vacuum deposition, sputtering, and ion plating on the substrate surface. Of cobalt or an alloy thin film mainly composed of cobalt by dry plating such as coating, ion beam sputtering, ECR (electron cycle tron resonance) plasma, electroplating, electroless plating, etc. By interposing the cobalt or an alloy thin film mainly containing cobalt between them, the amount of the sulfur component in the rubber composition can be significantly reduced as compared with the conventional one, and the compounding of the organic cobalt salt can be eliminated. As described above, even if the amount of sulfur in the rubber composition is reduced, or even if an organic cobalt salt is not used, metal materials such as steel and aluminum, and porosity It is possible to bond and compound rubber compositions to substrates made of various materials such as plastic materials such as rearylates, polyacrylates and polyamides. In this case, the temperature at which the rubber composition is vulcanized and heated during normal vulcanization Just by pressure bonding at the same temperature, the cobalt or alloy thin film containing cobalt as a main component and the vulcanized rubber composition are firmly bonded to each other to obtain a rubber-based composite material having good adhesiveness, and further the amount of sulfur is reduced. In addition, it is possible to eliminate the compounding of the organic cobalt salt, the adhesiveness hardly deteriorates even when the unvulcanized rubber composition is stored for a long period of time, and the heat aging resistance of the vulcanized rubber is significantly improved. It has been found that the rubber-based composite material can be improved, and accordingly, a rubber-based composite material such as a tire and a conveyor belt which is subjected to severe stress and strain can be preferably produced.

That is, when a rubber composition is adhered to a substrate such as a metal as described above, conventionally, in order to obtain good bondability, a large amount of a sulfur component is added to the rubber composition or a large amount of an organic cobalt salt is further added. However, according to the method of the present invention in which a cobalt or alloy thin film mainly containing cobalt is formed on a substrate and the rubber composition is compounded with the thin film, a small amount of the rubber composition is added to the rubber composition. Even if the addition of the sulfur component is eliminated and the addition of the organic cobalt salt is eliminated, a rubber-based composite material having excellent adhesion between the substrate and the rubber composition can be obtained.
Therefore, according to the present invention, it is possible to reduce the compounding amount of the sulfur component when joining the substrate and the rubber composition for the first time and to eliminate the addition of the organic cobalt salt.

Therefore, the present invention is a method for producing a rubber-based composite material by joining a base and a rubber composition, in which cobalt or an alloy thin film mainly containing cobalt is adhered and formed on the surface of the base,
Then, a method for producing a rubber-based composite material is provided, in which a rubber composition containing no organic cobalt salt is thermocompression-bonded and vulcanized and adhered onto the cobalt or an alloy thin film mainly containing cobalt. .

 Hereinafter, the present invention will be described in more detail.

The method for producing a rubber-based composite material according to the present invention is a composite by joining a base and a rubber composition, where the base is a metal such as steel, aluminum, copper, or a copper alloy, Polyesters such as polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyoxybenzoyl, polyamides such as 6-nylon, 6,6-nylon and aromatic polyamides, polyethers such as polyacetal, polyphenylene oxide, polyether ether ketone, polyphenylene sulfide Polysulfones such as polysulfone and polyether sulfone, polyimides such as polyimide, polyether imide, polyamide imide and poly bismaleimide, thermoplastic resins such as polycarbonate and phenol resin, formaldehyde such as melamine resin Resins, allyl resins such as diallyl phthalate, epoxy resins, silicone resins, thermosetting resins such as polyurethane, ceramics, glass, etc. may be used regardless of the material of the substrate. Also, there is no limitation on the shape or size of the substrate, and an appropriate material depending on the purpose,
A substrate of any shape and size can be selected and used. However, the present invention is particularly suitable when a metal substrate such as a steel wire, a steel cord, a steel tire cord, a steel cable, a steel land, a steel rod, a steel plate, or a steel cord such as a steel filament is compounded with a rubber composition. By combining these steel cords, etc. with a metal substrate and a rubber composition, a rubber-based composite using a core material of fibrous metal such as tires, power transmission belts, conveyor belts, hoses, etc. It is possible to manufacture a wide variety of rubber products and parts such as materials, anti-vibration rubber, seismic isolation materials, rubber rollers, and rubber screens. Here, the steel cord is
This is a general term for metallic reinforcing materials used for reinforcement or reinforcement of rubber articles.To explain this point in more detail, when steel cords are generally used for reinforcement or reinforcement of rubber articles, they are expanded to enhance their effect. It is a thin line that has been drawn. However, it is difficult to thin the steel cord (steel) as it is. Therefore, wet plating such as electroplating is used to adhere zinc, brass, etc. on the steel cord, and the thinning is smoothed by the action of these adhered metals. I am doing this. Therefore, the steel cord referred to in the present invention includes a steel cord whose surface is plated with a different metal.

When compounding the rubber composition with the above-mentioned substrate, first, if necessary, pretreatment is performed on the substrate surface, and then a cobalt thin film is formed on the substrate surface. When the substrate surface is pretreated here, the substrate surface is pretreated by a heat treatment method,
Examples of the method include a high frequency heating method, a solvent cleaning method, an ultrasonic cleaning method, a low temperature plasma method, and a reverse sputtering treatment method. One of these methods or a combination of two or more methods adheres to the substrate surface. Oil and lubricant are removed and activated, and the adhesion between the substrate and the cobalt or cobalt alloy thin film is improved, but such pretreatment can be effectively adopted when a substrate such as a steel cord is used as the substrate. . in this case,
Among these pretreatment methods, the low temperature plasma method and the reverse sputtering treatment method are particularly effective.

Further, as a method for forming cobalt or an alloy thin film mainly containing cobalt, electroplating, wet plating using a plating solution such as electroless plating, and vacuum deposition, ion plating, sputtering, and ion Beam sputtering method, ECR (electron cyclotron resonance)
A dry plating method such as a plasma method may be used. In the present invention, it is sufficient that a cobalt or cobalt alloy thin film can be formed, and any of the above methods can be suitably adopted. However, the wet plating method involves forming a metal thin film by immersing a substrate in a plating solution, which requires a problem of waste solution treatment with acids, alkalis, and complicated treatment steps such as post-plating treatment. In addition to problems such as difficult management, it is difficult to control the film thickness of the organic thin film, and the film thickness of the obtained metal thin film tends to be non-uniform. In some cases, it is necessary to set the film thickness to several μm or more. Therefore, depending on the type of composite to be manufactured, the inherent properties of the metal thin film cannot be ignored, and the flexibility of the composite may be impaired. is there. In contrast,
The dry plating method does not have such a problem, and has an advantage that the film thickness can be easily controlled and managed during thin film formation by an optical film thickness control method such as a λ / 4 control method. Is more preferable for.

In this case, the dry plating method for forming the cobalt or cobalt alloy thin film according to the present invention is, as described above, the vacuum deposition method, the ion plating method, the sputtering method, the ion beam, depending on the desired film thickness, thin film physical properties and the like. Various dry plating methods such as sputtering method and ECR (Electron Cyclotron Resonance) plasma method are adopted. When performing these dry plating methods, the ultimate vacuum, presence / absence of gas injection of argon, oxygen, etc., substrate temperature, annealing Etc. are appropriately selected. In the vacuum vapor deposition method and the ion plating method, one of evaporation methods such as resistance heating, induction heating, and electron beam heating is used as an evaporation source.In the ion plating method, high frequency plasma, arc plasma, DC voltage are used. Ionization of the evaporative substance and acceleration of the ionized evaporative substance are carried out using a method such as application, cluster ion beam, or hot cathode method. Further, in the sputtering method, various sputtering methods such as DC magnetron, two-pole direct current, and high frequency can be selected and used.

It should be noted that the cobalt alloy is mainly cobalt, and may be any as long as it does not impair the adhesiveness improving effect of the present invention, for example, Co-Ni, Co-P, Co-Cr, Co-Zn and the like. To be

The film thickness of the cobalt or cobalt alloy thin film obtained by the above method is not particularly limited, but 10 Å to 100 μm is preferable from the viewpoint of productivity of the thin film, and from the viewpoint of a thin film that does not affect the properties of the composite, 10Å to 1 μm is preferable.

Then, the method for producing a rubber-based composite material of the present invention is a method for producing a rubber-based composite material by a method of thermocompression bonding and vulcanization adhesion of a rubber composition on the cobalt or cobalt alloy thin film obtained by the above method. Is.

Here, as the rubber component in the rubber composition used in the present invention, natural rubber (NR) and synthetic rubber having a carbon-carbon double bond in the structural formula may be used alone or in a blend of two or more kinds. . The synthetic rubber is isoprene,
Butadiene, polyisoprene rubber (IR) which is a homopolymer of a conjugated diene compound such as chloroprene, polybutadiene rubber (BR), polychloroprene rubber, etc., the conjugated diene compound and styrene, acrylonitrile, vinyl pyridine, acrylic acid, methacrylic acid, Styrene-butadiene copolymer rubber (SBR) which is a copolymer with vinyl compounds such as alkyl acrylates and alkyl methacrylates,
Vinyl pyridine butadiene styrene copolymer rubber, acrylonitrile butadiene copolymer rubber, acrylic acid butadiene copolymer rubber, methacrylic acid butadiene copolymer rubber,
Methyl acrylate butadiene copolymer rubber, methyl methacrylate butadiene copolymer rubber, methyl methacrylate butadiene copolymer rubber, ethylene, propylene,
Copolymers of olefins such as isobutylene and diene compounds [eg isobutylene isoprene copolymer rubber (II
R)] Copolymer of olefins and non-conjugated dienes (EPD
M) [eg ethylene, propylene, cyclopentadiene terpolymer, ethylene propylene-5-ethylidene-2-norbornene terpolymer, ethylene propylene-1,4-hexadiene terpolymer], cycloolefin It includes a polyalkenamer obtained by ring-opening polymerization [for example, polypentenamer], a rubber obtained by ring-opening polymerization of an oxirane ring [for example, sulfur-vulcanizable polyepichlorohydrin rubber], polypropylene oxide rubber and the like. Also included are halides of the various rubbers, such as chlorinated isobutylene isoprene copolymer rubber (Cl-IIR) and brominated isobutylene isoprene copolymer (Br-IIR). Further, a ring-opening polymer of norbornene can also be used.
Furthermore, as the blended rubber, a saturated elastic body such as epichlorohydrin rubber, polypropylene oxide rubber, or chlorosulfonated polyethylene may be blended with the above-mentioned rubber and used.

The rubber composition used in the present invention, in addition to the above rubber component, according to a conventional method, carbon black, silica, calcium carbonate, calcium sulfate, clay, diatomaceous earth, depending on the purpose and application of the rubber-based composite to be produced, Fillers such as mica, mineral oils, vegetable oils, softening agents such as synthetic plasticizers, vulcanization accelerating aids such as stearic acid, antioxidants, sulfur and other crosslinking agents, etc. can be added, but organic cobalt No salt is added. According to the present invention, by forming a cobalt or cobalt alloy thin film, even if the composition does not use the organic cobalt salt in the rubber composition at all, without impairing the bonding force between the rubber composition and various substrates, It is possible to provide excellent adhesion, and therefore, it is possible to obtain a rubber-based composite material having excellent durability, which is capable of suppressing the deterioration of the adhesive force due to the addition of the organic cobalt salt with time, the breaking strength, the heat aging such as elongation, and the like. it can.

The bonding of the rubber composition and the substrate on which the cobalt or cobalt alloy thin film is formed is performed by vulcanizing and adhering the rubber composition on the cobalt or cobalt alloy thin film by heating and pressure bonding as described above. Examples of the vulcanization method used for the production of the composite material include, in addition to the general and most important sulfur vulcanization, organic sulfur vulcanization using organic sulfur compounds such as dithiodimorpholine and thiuram vulcanization. However, the method using sulfur vulcanization is particularly preferable. here,
When using the sulfur vulcanization or organic sulfur vulcanization method, it is necessary to use 0.5 to 4 parts of sulfur or sulfur of an organic compound, that is, the sulfur component with respect to 100 parts of the rubber component in the rubber composition. It is suitable in terms of storage stability of the rubber composition and heat aging resistance of the vulcanized rubber composition. That is, as described above, in the conventional joining of the rubber composition and the substrate, the amount of the sulfur component was 4 to 8 parts in order to maintain a stable adhesive force. According to the present invention, by interposing a cobalt or cobalt alloy thin film between the rubber composition and the substrate, the bonding strength between these is improved, and even if the sulfur content is less than 4 parts, excellent adhesive strength is exhibited. Therefore, heat aging of the rubber after vulcanization due to excessive use of sulfur can be avoided, and rubber properties such as tensile strength, breaking strength, and elongation can be favorably maintained, and a rubber-based composite material with excellent durability can be obtained. be able to.

The operations of heating and pressure bonding performed in the method for producing a rubber-based composite material of the present invention form a cobalt or cobalt alloy thin film at a temperature and pressure that do not impair the original shape of the substrate and the rubber composition. Adhesion of the rubber composition to the cured substrate and supplying the activating heat energy necessary to form the reaction between the cobalt or cobalt alloy thin film and the vulcanized rubber composition, and further vulcanization of the rubber composition. It is carried out for the purpose of supplying the necessary activation heat energy, and the appropriate temperature and pressure for this purpose are appropriately selected depending on the types of the substrate and the rubber composition, and the range is not particularly limited.

EFFECTS OF THE INVENTION As described above, according to the present invention, cobalt or an alloy thin film mainly containing cobalt is adhered and formed on the surface of a substrate, and then a rubber composition is heat-pressed onto the cobalt thin film for vulcanization adhesion. Therefore, even if a small amount of sulfur is used for vulcanization, and even if a rubber composition containing no organic cobalt salt is used, the base material and the rubber composition can be composited with very good bondability. A small amount of sulfur component may be added to the rubber composition to perform sulfur vulcanization or organic sulfur vulcanization, and since the use of an organic cobalt salt can be eliminated, a large amount of sulfur component and organic cobalt can be added. Various problems associated with the use of salt are solved, a rubber-based composite material having excellent heat aging resistance and high adhesive strength can be obtained, and it is difficult to form a composite with a conventional rubber composition as a substrate. Material, shape, Sizes can be used.

Hereinafter, the present invention will be specifically described by showing Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1, Comparative Example 1] As a base material, a steel piece (material SS-41) having a width of 25 mm, a length of 60 mm, and a thickness of 2.3 mm, an aluminum piece, and a brass piece were used, and these base materials were washed and dried. Thereafter, a Co thin film having a film thickness shown in Table 2 was formed on each substrate material surface by the following dry plating methods A to C. The film thickness was measured using Taristep manufactured by Taylor Hobson.

A. Vacuum deposition method The test piece (base material above) was placed in a vacuum deposition apparatus, the inside of the chamber was set to a vacuum degree of 10 ^-5 Torr or less, and then a small amount of Ar gas was introduced into the chamber to set the vacuum degree to 5 ×. After adjusting to 10 ⁻³ Torr, the surface of the test piece was cleaned for 5 minutes by RF glow discharge using an RF high frequency power source. After cleaning, the RF glow discharge was stopped, and a metal thin film (Co thin film) was deposited on the surface of the test piece by a resistance heating method.

B. Sputtering method Using a magnetron sputtering device, place the test piece (the above-mentioned substrate material) on the substrate holder inside it, and make the inside of the chamber a vacuum degree of 10 ^-5 Torr or less.
After introducing gas and adjusting the vacuum to 0.1 Torr, 13.56 MH
The surface of the test piece was cleaned by high frequency glow discharge of z for 5 minutes. After cleaning, stop high frequency glow discharge,
A DC voltage of −600 V was applied to the metal sample target, and sputtering was performed with Ar plasma at a target current of 0.5 A to form a metal thin film (Co thin film) on the surface of the test piece.

C. Ion plating method The test piece (basic material above) is installed in an ion plating device, Ar plasma is generated by a high frequency power source according to a conventional method, and a metal sample (Co) is evaporated by resistance heating in that state. Thus, a metal thin film (Co thin film) was formed on the surface of the test piece.

An unvulcanized rubber composition I of the type shown in Table 1 below was laminated on a basic Co thin film having a Co thin film obtained by the dry plating method, and then the rubber was pressed at a temperature of 145 ° C. for 40 minutes. The composition was vulcanized and bonded.

The composite material obtained by vulcanizing and adhering the above rubber composition was subjected to a 90 ° peel test at a pulling speed of 50 mm / min using a tensile tester to evaluate the adhesiveness.

For further comparison, the rubber composition was directly vulcanized and adhered according to the above method without forming a cobalt thin film on the surface of the substrate,
A composite material without a cobalt thin film layer was produced and evaluated for adhesion in the same manner as above.

 Table 2 shows the above adhesiveness evaluation results.

As is clear from the results in Table 2, the adhesive properties of the rubber composites obtained by vulcanizing and adhering the rubber composition directly onto the metal substrate (Comparative Example) were very poor. is there. On the other hand, the adhesiveness of the one obtained by the method for manufacturing a rubber-based composite material (Example) in which a cobalt thin film is adhered and formed on a metal substrate and then a rubber composition is vulcanized and adhered to the steel, aluminum, Excellent adhesion to any base material of brass, further, according to the method for producing a rubber-based composite material of the present invention, sufficient adhesion is obtained without compounding an organic cobalt salt in the rubber composition. It is found that a rubber-based composite material having the same can be obtained. Also,
It was confirmed that the method for producing a rubber-based composite material of the present invention can provide a composite material having excellent adhesiveness regardless of the thin film forming method and the thickness of the Co thin film.

[Example 2] Instead of the conventional metal substrate of Example 1, polyarylate (manufactured by Unitika Ltd .; trade name U polymer), polyamide (6,
6 Nylon), polyether (Engineering Plastics Co .; trade name Noryl), polysulfone (Nissan Chemical Co., Ltd .; trade name PES), polycarbonate 25mm width x length 6
A composite material was formed in the same manner as in Example 1 except that a plastic equipment material having a thickness of 0 mm and a thickness of 2 mm was cut out and the surface thereof was degreased with a solvent was used, and the adhesiveness was evaluated.

Table 3 shows the film thickness of the Co thin film layer obtained at the time of forming the composite material and the evaluation result of the adhesiveness.

From the results shown in Table 3, even if the base material is changed from the metal of Example 1 to plastic, by using the method for producing a rubber-based composite material of the present invention, as in Example 1, various types of plastic substrates can be obtained. On the other hand, a composite material having excellent adhesiveness can be obtained regardless of the Co thin film forming method and the film thickness of the Co thin film, and a composite material having excellent adhesiveness can be obtained even if an organic cobalt salt is not added to the rubber composition. It was confirmed that it was obtained, and the effect of the present invention was confirmed.

[Example 3, Comparative Example 2] Rubber was prepared in the same manner as in Example 1 and Comparative Example 1 except that the rubber compositions of Examples 1 and Comparative Example 1 were replaced with rubber compositions of the types shown in Table 4. -Based composite materials were produced and evaluated for adhesion.

Table 5 shows the film thickness and the adhesiveness evaluation result of the Co thin film layer obtained at the time of manufacturing the rubber-based composite material.

From the results shown in Table 5, according to the method for producing a rubber-based composite material of the present invention, excellent adhesion is exhibited even when the rubber composition does not contain an organic cobalt salt. Even if the amount of carbon is different as in rubber compositions II to IV,
Alternatively, it has been found that a composite material having excellent adhesiveness can be obtained irrespective of the kind of the rubber composition even by using the rubber composition V having a different rubber type from these rubber compositions II to IV. Further, as in Example 1, it was confirmed that a rubber-based composite material having excellent adhesiveness can be obtained regardless of the Co thin film forming method on a substrate made of any of steel, aluminum and brass.

[Example 4] A rubber-based composite material was produced in the same manner as in Example 3 except that the same plastic substrate material as that used in Example 2 was used instead of the metal substrate material of Example 3, and the adhesive property was improved. Was evaluated.

Table 6 shows the film thickness and the adhesiveness evaluation results of the Co thin film layer obtained during the production of the rubber-based composite material.

From the results shown in Table 6, by adopting the method for producing a rubber-based composite material of the present invention, even if the base material is changed from the metal of Example 3 to plastic, various types of plastic substrates can be obtained as in Example 3. On the other hand, it is possible to obtain a rubber-based composite material having excellent adhesiveness regardless of the thin film forming method and the type of rubber composition, and that the adhesiveness is good even if the rubber composition does not contain an organic cobalt salt. confirmed.

[Example 5, Comparative Example 3] A 40 Å cobalt thin film was adhered and formed on the brass piece of Example 1 by a vacuum deposition method, and then the rubber composition shown in Table 1 was used for I for 40 minutes at a temperature of 145 ° C. The adhesiveness and the adhesiveness of the manufactured rubber-based composite material which was pressure-bonded and vulcanized and adhered and after being heated at a temperature of 100 ° C. for 24 hours were evaluated in the same manner as in Example 1, and these adhesiveness and adhesiveness were evaluated. The heat aging degree was evaluated from the state of the rubber composition after the evaluation.

Further, for comparison, a cobalt naphthenate-containing rubber composition prepared by blending 2 parts of cobalt naphthenate in place of the vegetable oil or mineral oil of Table 1 directly on the same brass piece as in Example 1 was used. The heat aging degree of the rubber composite material produced by thermocompression bonding and vulcanization adhesion was evaluated in the same manner as in.

 Table 7 shows the evaluation results of the heat aging degree.

From the results shown in Table 7, the rubber-based composite material produced by using the rubber composition containing cobalt naphthenate, which was conventionally considered to have good adhesiveness, shows a remarkable performance decrease due to heat aging, whereas It was found that the rubber-based composite material produced according to the production method had almost no change in performance, and was excellent in heat aging prevention performance.

[Example 6 and Comparative Example 4] A brass-plated cord system of 1.2 mm having a stranded structure 3 + 6 was used as a substrate, and the brass-plated steel cord surface was coated with the above-mentioned dry plating method A to C. A Co thin film having a film thickness shown in Table 9 was formed.

An unvulcanized rubber composition VI or VII of the type shown in Table 8 below was laminated on the Co thin film of the substrate having the Co thin film obtained by the above dry plating method, and then pressed at a temperature of 145 ° C. for 40 minutes. The above rubber composition was vulcanized and adhered.

The composite material obtained by vulcanizing and adhering the above rubber composition was subjected to a peel test with a tensile tester at a pulling speed of 50 mm / min to evaluate the adhesiveness.

For further comparison, without forming a cobalt thin film on the surface of the base material, the rubber composition is vulcanized and adhered according to the above method,
A composite material without a cobalt thin film layer was produced and evaluated for adhesion in the same manner as above.

 Table 9 shows the results of the above adhesiveness evaluation.

From the results of Table 9, according to the present invention, a thin film forming method,
Regardless of the thickness of the Co thin film, a rubber composition containing no organic cobalt salt (rubber composition VI) has almost the same degree as the rubber composition containing the organic cobalt salt (rubber composition VII). It was confirmed that a rubber-based composite material having adhesive strength and adhesive performance was obtained, while on the other hand, in the case of the comparative example in which the Co thin film was not formed on the brass-plated steel cord substrate, the adhesiveness was poor without adding the organic cobalt salt. It was

[Example 7, Comparative Example 5] The same brass-plated steel cord as that used in Example 6 was used as a substrate, and a 400 Å Co thin film was formed on the surface of the substrate by the sputtering method of B. The rubber compositions VI and VII shown in Table 8 and the rubber compositions VIII to XI shown in Table 10 were vulcanized and adhered in the same manner as in Example 6 to obtain a rubber-based composite material.

The rubber composite material thus obtained was evaluated for adhesiveness in the same manner as in Example 6, and for comparison, the rubber composition was directly added according to the above method without forming a cobalt thin film on the surface of the base material. A sulfur-bonded composite material was produced by manufacturing a composite material without a cobalt thin film layer, and the adhesiveness was evaluated in the same manner as above.

 Table 11 shows the above adhesiveness evaluation results.

Furthermore, regarding the rubber-based composite material with the cobalt thin film formed on the surface of the substrate, the elastic modulus (elastic modulus corresponding to 50% strain of the stress-strain curve) and rupture strength after heat treatment at 100 ° C for 24 hours The elongation at break was measured and compared with the physical properties before heating.

 Table 12 shows the above measurement results.

From the results shown in Table 11, when a rubber-based composite material is produced without depositing a Co thin film on a substrate, adhesion between the substrate and the rubber composition may be defective depending on the type of the rubber composition. It was confirmed that according to the method, a rubber composition having excellent adhesiveness was obtained regardless of the kind of the rubber composition.

Further, from the results in Table 12, as the blending amount of sulfur in the rubber composition increases, the breaking strength, the retention of the breaking elongation before and after heating is decreased, and also the organic cobalt in the rubber composition. When a salt is added, the breaking strength and the retention rate of the breaking elongation before and after heating are further reduced, and it is difficult to compound a large amount of sulfur in the rubber composition or to add an organic cobalt salt to the rubber-based composite. It is confirmed that this is not preferable for the material, but as is clear from Table 11, when the Co thin film is formed, the compounding amount of sulfur is small as in the rubber composition VIII and the rubber composition X. In addition, the adhesion between the substrate and the rubber composition is excellent without adding an organic cobalt salt as in the rubber compositions VI and VIII and IX. Therefore, according to the present invention, a large amount of sulfur component The above-mentioned physical properties and resistance due to the composition and use of organic cobalt salt It was found that the deterioration of heat aging can be prevented.

[Example 8, Comparative Example 6] A substrate similar to that in Example 7 was used, and about 400 Å Co was formed on the surface of the substrate by the sputtering method in the same manner as in Example 7.
After forming a thin film, and then laminating the rubber composition VIII shown in Table 10 on the CoW thin film, the heating time was changed at 145 ° C. to produce a rubber-based composite material, and the same procedure as in Example 7 was performed. And the adhesiveness was evaluated.

For further comparison, without forming a cobalt thin film on the surface of the base material, the rubber composition is vulcanized and adhered according to the above method,
A composite material without a cobalt thin film layer was produced and evaluated for adhesion in the same manner as above.

 The above-mentioned evaluation of adhesiveness is shown in Table 13.

From the results of Table 13, in the case of producing a rubber-based composite material without forming a Co thin film on the surface of a substrate using a rubber composition containing no cobalt naphthenate, the adhesive force increases with increasing the flow time, Although the improvement of the adhesive performance can be seen, even if the vulcanization time reaches 100 minutes, a sufficiently satisfactory adhesive strength and adhesive performance cannot be obtained, whereas according to the method of the present invention, the vulcanization time is about 20 minutes. But sufficient adhesion between the substrate and the rubber composition,
It was confirmed that a rubber-based composite material having excellent adhesion performance was obtained.

[Example 9] The same substrate as in Example 7 was used, and about 400Å of Co was formed on the surface of the substrate by the sputtering method in the same manner as in Example 7.
A thin film was formed and then, on the Co thin film, the rubber composition VI shown in Table 8 above and the rubber compositions VIII and IX shown in Table 10 above were formed.
And rubber compositions XII to XIV shown in Table 14 below were each used to produce a rubber-based composite material in the same manner as in Example 7, and the adhesive properties before and after heat treatment at 100 ° C. for 24 hours were evaluated as in Example. Evaluation was made in the same manner as in 7.

 Table 15 shows the above adhesion evaluation results.

From the results shown in Table 15, according to the method of the present invention, a rubber-based composite having excellent adhesion performance between the substrate and the rubber composition was obtained irrespective of the blending amount of sulfur in the rubber composition (all do not contain cobalt naphthenate). It was confirmed that the material was obtained. Further, as the sulfur content increases, the adhesive strength and the retention rate of the adhesive strength rather decrease, and it is not preferable to add a large amount of sulfur to the rubber composition in terms of adhesiveness, and the sulfur content is lower than that of the rubber. It was confirmed that about 1 part by weight per 100 parts by weight of the component can provide a rubber-based composite material having sufficient adhesiveness and excellent heat aging resistance.

[Example 10, Comparative Example 7] The same brass-plated steel cord substrate as in Example 6 was used, and a film thickness of about 0.1 μm was formed on the surface of the substrate by electrolytic plating.
Co thin film was formed. Then, the rubber composition VI shown in Table 8 and the rubber composition VI shown in Table 10 were formed on the Co thin film.
After bonding II, vulcanization adhesion was performed in the same manner as in Example 6 to produce a rubber-based composite material, and the same adhesion evaluation was performed.

For further comparison, without forming a cobalt thin film on the surface of the base material, the rubber composition is vulcanized and adhered according to the above method,
A composite material without a cobalt thin film layer was produced and evaluated for adhesion in the same manner as above.

 Table 16 shows the results of the above adhesiveness evaluation.

From the results in Table 16, it was confirmed that even if the Co thin film was formed by electroplating, the rubber composition containing no cobalt naphthenate could be bonded to the substrate with good adhesive strength.

[Example 11 and Comparative Example 8] A ceramic plate having a width of 12.5 mm, a length of 60 mm and a thickness of 4 mm containing 90% of alumina was used as a substrate material, and the surface of the ceramic plate was degreased with a solvent, and then Example 1 was used. A cobalt thin film having a thickness of 400 Å is adhered and formed on the ceramic plate by the sputtering method described above, and then the rubber composition I shown in Table 1 is pressed at a temperature of 145 ° C. for 40 minutes for vulcanization adhesion. A rubber-based composite material was manufactured and its adhesive performance was evaluated.

For comparison, the rubber composition I was directly vulcanized and adhered according to the above method without forming a cobalt thin film on the surface of the base material to produce a composite material having no cobalt thin film layer, and the adhesiveness was evaluated in the same manner as above. did.

 Table 17 shows the results of the above-mentioned adhesiveness evaluation.

From the results of Table 17, even if the substrate material is a ceramic material, according to the method of the present invention in which a cobalt thin film is adhered and formed on the surface of the substrate, excellent adhesion performance is obtained without compounding an organic cobalt salt in the rubber composition. It was confirmed that a rubber-based composite material was obtained, and the effect of the present invention was confirmed.

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Claims (6)

(57) [Claims] 1. A method for producing a rubber-based composite material comprising a substrate and a rubber composition bonded together, wherein cobalt or an alloy thin film containing cobalt as a main component is adhered and formed on the surface of the substrate, and then the cobalt or cobalt is the main component. A method for producing a rubber-based composite material, which comprises subjecting a rubber composition containing no organic cobalt salt to thermocompression bonding and vulcanizing adhesion on the alloy thin film. 2. A method according to claim 1, wherein the substrate is a metal. 3. The method according to claim 1, wherein cobalt or an alloy thin film containing cobalt as a main component is adhered and formed by a dry plating method. 4. The method according to claim 1 or 2, wherein a cobalt or alloy thin film mainly containing cobalt is deposited by electrolytic plating or electroless plating. 5. The method according to any one of claims 1 to 4, wherein the vulcanization is sulfur vulcanization or organic sulfur vulcanization. 6. The method according to claim 5, wherein the sulfur component is used in an amount of 0.5 to 4 parts by weight based on 100 parts by weight of the rubber component in the rubber composition.