JPS62189117A - Manufacture of rubber composite material - Google Patents

Abstract

PURPOSE:To enable the titled material to keep stable adhesiveness for a long period of time by improving thermal aging properties, by a method wherein an rubber compos ite is vulcanized and stuck on the upper part of a cobalt or cobalt alloy film, which has been formed on the surface of a base through adhesion, by performing hot press bonding. CONSTITUTION:A cobalt or cobalt alloy film is formed on the surface of a metallic base by a dry plating method such as vacuum evaporation or sputtering or ionic plating or ion beam sputtering or ECR method, or electric plating or electroless plating method. Sulphur vulcanization or organic sulphur vulcanization is applied to the upper part of the same by making use of a 0.5-4wt part of rubber composite and sulphur contents to 100wt part rubber contents. In this case, a rubber series composite material whose adhesion is favorable is obtained by sticking firmly the cobalt or cobalt alloy film and vulcanized rubber composite to each other by performing only press bonding at the temperature to the same extent as ordinary vulcanization. In addition to the above, as a quantity of sulphur can be reduced and the organic cobalt salt can be reduced or compounding of the same can be eliminated, adhesion hardly deteriorates even if an unvulcanized rubber composite is kept for a long period of time and thermal aging properties of vulcanized rubber can be improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a rubber-based composite material in which a composite is produced by vulcanizing and adhering a rubber composition to a substrate such as metal or plastic.

■Beito Gishin Traditionally, rubber-based composite materials such as tires and conveyor belts
When metal is used as the reinforcing base, for example, brass plating (plus plating) is applied to a steel cord, a sulfur component, a vulcanization accelerator, and an organic cobalt salt or organic cobalt salt that has an effective effect on vulcanization adhesion are used. It is manufactured by a method such as vulcanization bonding of a rubber composition containing resorcinol, hexamethyltetramine, silica, etc., but in such a method, the addition of sulfur components and organic cobalt salts, etc. is known to be an important factor for stabilizing the

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 organic cobalt salts such as cobalt naphthenate can stably bond the rubber composition and the substrate, their addition is essential, and usually about 1 to 3 parts can be added. It is being done.

However, when a large amount of 4 to 8 parts by weight of sulfur is blended into a rubber composition as described above, the rubber composition before vulcanization bonding, that is, the unvulcanized rubber composition, can last for a long time. If the rubber composition is left for a long time, sulfur will bloom from the rubber composition, causing a major problem in the storage stability of the unvulcanized rubber composition, and the rubber strength of the rubber composition after vulcanization will deteriorate significantly due to thermal deterioration. There is a defect that it decreases.

In addition, while the use of organic cobalt salts allows stable adhesion between the substrate and the rubber composition to be obtained by appropriately controlling the vulcanization rate, there is a risk that the adhesive strength may deteriorate over time, and the breaking strength and elongation of the rubber may deteriorate. There is a problem in that the tendency for temperature etc. to decrease due to heat aging is significantly increased.

For this reason, we have reduced the amount of sulfur components (sulfur during sulfur vulcanization or sulfur compounds during organic sulfur vulcanization) to achieve excellent heat aging resistance and stable adhesion to substrates such as metals and plastics. There is a need for a method for manufacturing rubber-based composite materials that provides good properties, and also that provides stable adhesion to substrates such as metals and plastics even when the amount of organic cobalt salt added is reduced. A method is needed.

The present invention was made in view of the above circumstances, and it is possible to reduce the amount of sulfur component necessary for vulcanization adhesion of a rubber composition, and furthermore, it is possible to reduce the amount of organic cobalt salt or eliminate the combination of these components. possible, and therefore has excellent heat aging resistance.
Moreover, it is an object of the present invention to provide a method for producing a rubber-based composite material that has high bonding strength and stable adhesive properties over a long period of time.

In order to achieve the above object, the inventors of the present invention have conducted intensive studies on the bonding method between the substrate and the rubber composition. A cobalt or cobalt alloy thin film is formed by a dry plating method such as ion blating, ion beam sputtering, or ECR (electron cyclotron resonance) plasma method, or by an electroplating or electroless plating method, and the cobalt or cobalt alloy thin film is formed between the substrate and the rubber composition. By interposing a cobalt or cobalt alloy thin film, the amount of sulfur components in the rubber composition can be significantly reduced compared to conventional ones, and the amount of organic cobalt salts used can be reduced or the blending of these components can be eliminated. Even if the amount of sulfur in the rubber composition is reduced in this way, and even without the use of organic cobalt salts, metal materials such as steel and aluminum, plastic materials such as polyarylate, polyacrylate, polyamide, etc.
Rubber compositions can be bonded and composited to substrates made of many types of materials; in this case, the above-mentioned cobalt or The cobalt alloy thin film and the vulcanized rubber composition firmly adhere to each other to obtain a rubber-based composite material with good adhesive properties;
Furthermore, since the amount of sulfur and the amount of organic cobalt salt can be reduced or eliminated, the adhesive properties of the unvulcanized rubber composition will hardly deteriorate even if it is stored for a long period of time. It has been found that the heat aging resistance of rubber can be significantly improved, and therefore rubber-based composite materials that are subjected to severe stress and distortion, such as tires and conveyor belts, can be suitably produced.

That is, as mentioned above, when bonding a rubber composition to a substrate such as a metal, conventionally, in order to obtain good bonding properties, a large amount of sulfur component was blended into the rubber composition, or a large amount of organic cobalt salt was added. However, according to the method of the present invention, which forms a cobalt or cobalt alloy thin film on a substrate and composites the rubber composition with it, it is possible to add a small amount of sulfur component to the rubber composition. A rubber-based composite material with extremely excellent adhesion between the substrate and the rubber composition can be obtained by simply adding organic cobalt salts, and even without the addition of an organic cobalt salt. This makes it possible to reduce the amount of sulfur component added when bonding, and in some cases, reduce or eliminate the addition of organic cobalt salts.

Therefore, the present invention provides a method for manufacturing a rubber composite material formed by bonding a substrate and a rubber composition, in which a thin film of cobalt or a cobalt alloy is deposited on the surface of the substrate, and then a rubber composition is formed on the thin film of cobalt or a cobalt alloy. The present invention provides a method for producing a rubber-based composite material by heat-pressing and vulcanization bonding.

The present invention will be explained in more detail below.

The method for producing a rubber-based composite material according to the present invention is to combine a substrate and a rubber composition to form a composite material. Here, the substrate is made of metal such as steel steel, aluminum, copper, copper alloy, etc. , polyesters such as polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyoxybenzoyl, polyamides such as 6-nylon, 6.6-nylon and aromatic polyamide, polyacetal, polyphenylene oxide, polyether ether ketone, polyphenylene sulfide, etc. Polysulfones such as polyether, polysulfone, polyethersulfone, polyimides such as polyimide, polyetherimide, polyamideimide, polybismaleimide, thermoplastic resins such as polycarbonate, formaldehyde resins such as phenol resins, melamine resins, diallyl phthalate, etc. Any material of the substrate can be used, such as allyl resin, epoxy resin, silicone resin, thermosetting resin such as polyurethane, ceramic, glass, etc. Further, there are no restrictions on the shape or size of the substrate, and a substrate of an appropriate material, shape, and size can be selected and used depending on the purpose. However, the present invention is particularly suitable for compounding metal substrates such as steel cords such as steel wire, steel cord, steel tire cord, steel cable, steel strand, steel rond, steel plate and steel filament with a rubber composition. By combining these metal substrates such as steel cords with rubber compositions, rubber-based composite materials using fibrous metal as the core material for tires, power transmission belts, conveyor belts, hoses, etc. We can manufacture a wide variety of rubber products and parts, such as anti-vibration rubber, seismic isolation materials, rubber rollers, and rubber screens. Note that steel cord is a general term for metal reinforcing materials used to strengthen or reinforce rubber articles.To explain this point in more detail, steel cord is generally used to strengthen or reinforce rubber articles. In order to enhance the effect, wires that have been drawn into thinner wires are used.

However, it is difficult to thin steel cord (steel) as it is, so wet plating is applied on the steel cord.
For example, electroplating is used to deposit zinc, brass, etc., and the thinning of the wire is achieved smoothly by the action of these deposited metals. Therefore, the steel cord referred to in the present invention also includes steel cords whose surfaces are plated with different metals.

When compounding a rubber composition onto the above-mentioned substrate, first, the surface of the substrate is pretreated if necessary, and then a Cobal)Fl film is formed on the surface of the substrate. When pre-treating the substrate surface here, the pre-treatment methods for the substrate surface include heat treatment,
Examples include high frequency heating method, solvent cleaning method, ultrasonic cleaning method, low temperature plasma method, reverse sputtering method, etc., and by performing one or a combination of two or more of these methods, it is possible to adhere to the substrate surface. Oils, lubricants, etc. 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 employed 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 sputter treatment method are particularly effective.

In addition, methods for forming cobalt or cobalt alloy thin films include electroplating, electroless plating, and other wet plating methods using plating solutions, vacuum evaporation, ion blating, sputtering, ion beam sputtering, Examples include dry plating methods such as ECR (electron cyclotron resonance) plasma method. 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 employed. but,
In the wet plating method, a thin metal film is formed by immersing the substrate in a plating solution, and there are problems with waste liquid treatment using acids, alkalis, etc., and complicated processing steps such as post-plating treatment are required, making process control difficult. In addition, it is difficult to control the thickness of the metal thin film, and the thickness of the obtained metal thin film tends to be uneven, and it takes several microns to form a metal thin film with a uniform thickness. In some cases, it may be necessary to make the film thicker than that, and therefore, depending on the type of composite to be manufactured, the inherent properties of the metal thin film may be ignored, and the flexibility of the composite may be impaired. On the other hand, the dry plating method does not have such problems (and has the advantage that the film thickness can be easily controlled and managed during thin film formation using optical film thickness control methods such as the λ/4 control method). , more preferred for the purposes of the present invention.

In this case, the dry plating method for forming the cobalt alloy thin film according to the present invention may be vacuum evaporation method, ion blating method, sputtering method, or Various dry plating methods such as ion beam sputtering method and ECR (electron cyclotron resonance) plasma method are employed, but when performing these dry plating methods, the ultimate vacuum, whether or not gas such as argon or oxygen is injected, and the substrate temperature are , annealing, etc. are selected as appropriate. In addition, in the vacuum evaporation method and the ion blating method, one of the evaporation methods such as resistance heating, induction heating, and electron beam heating is used as the evaporation source, and in the ion blating method, high frequency plasma, arc plasma, DC voltage, etc. application, cluster ion beam,
Ionization of the evaporated material and acceleration of the ionized evaporated material are performed using a method such as a hot cathode method. Further, in the sputtering method, various sputtering methods such as DC magnetron, bipolar direct current, high frequency, etc. can be selected and used.

The cobalt alloy may be any cobalt-based alloy as long as it does not impair the adhesion improvement effect of the present invention, such as old Co and C.

-P, Go-Cr, Co-Zn, etc.

There is no particular limit to the thickness of the cobalt or cobalt alloy thin film obtained by the above method, but 10 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. In particular, 10 to 1 μm is preferable.

Next, in the method for producing a rubber-based composite material of the present invention, a rubber-based composite material is produced by a method of heat-pressing and vulcanizing a rubber composition onto the cobalt or cobalt alloy thin film obtained by the above method. It 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 can be used alone or in a blend of two or more. . The synthetic rubbers include polyisoprene rubber (IR), polybutadiene rubber (BR), and polychloroprene rubber, which are homopolymers of conjugated diene compounds such as isoprene, butadiene, and chlorobrene, and styrene, acrylonitrile, and the like. Styrene-butadiene copolymer rubber (S
BR), 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, etc., copolymers of olefins such as ethylene, propylene, isobutylene, and diene compounds [e.g. isobutylene isoprene copolymer rubber (I I R)] Olefins and a non-conjugated diene copolymer (EPDM) [e.g., ethylene, propylene, cyclopentadiene terpolymer, ethylene propylene-5-ethylene triethylene-2-norbornene terpolymer,
ethylene propylene-1,4-hexadiene terpolymer], polyalkenamers obtained by ring-opening polymerization of cycloolefins [e.g. polypentenamer], rubbers obtained by ring-opening polymerization of oxirane rings [e.g. polyepichlorohydrin rubber], polypropylene oxyto rubber, etc. Also included are halides of the various rubbers mentioned above, such as chlorinated isobutylene isoprene copolymer rubber (C1-■■R), brominated isobutylene isoprene copolymer rubber (Br-TIR), and the like. Furthermore, ring-opened polymers of norbornene may also be used. Furthermore, as a blended rubber, a saturated elastic material such as epichlorohydrin rubber, polypropylene oxide rubber, or chlorosulfonated polyethylene may be blended with the above-mentioned rubber.

In addition to the above-mentioned rubber components, the rubber composition used in the present invention may include carbon black, silica, calcium carbonate,
Fillers such as calcium sulfate, clay, diatomaceous earth, and mica, softening agents such as mineral oil, vegetable oil, and synthetic plasticizers, vulcanization accelerators such as stearic acid, antiaging agents, sulfur, and other crosslinking agents are added. Furthermore, an organic cobalt salt such as naphthenic cobalt salt can be added if necessary. In this case, the amount of organic cobalt salt added is 10% of the rubber component.
0 parts (parts by weight, the same applies hereinafter) to 1, which is the normal usage amount.
~3 parts or more, and even if the organic cobalt salt is used in the usual amount, according to the present invention, by reducing the amount of the sulfur component used, a good rubber-based composite material can be obtained. It is better to avoid using large amounts of organic cobalt salt, and for this reason, the amount of organic cobalt salt added is 3.
It is preferable to use no more than 1 part, more preferably no more than 2 parts, and most preferably no organic cobalt salt. According to the invention,
By forming a cobalt or cobalt alloy thin film, the amount of organic cobalt salt used in the rubber composition can be reduced, or even if the composition does not use organic cobalt salt at all, it is possible to bond the rubber composition and various substrates. A highly durable rubber that can provide excellent adhesion without loss of strength, and can therefore suppress deterioration of adhesive strength over time due to the addition of organic cobalt salts, as well as heat aging such as breaking strength and elongation. system composite material can be obtained.

The rubber composition and the substrate on which the cobalt or cobalt alloy thin film is formed are bonded by heat-pressing and vulcanizing the rubber composition onto the cobalt or cobalt alloy thin film as described above. In addition to sulfur vulcanization, which is the most common and most important vulcanization method used in the production of composite materials, organic sulfur vulcanization using organic sulfur compounds such as dithiodimorpholine and thiuram vulcanization is also used. Among these, a method using sulfur vulcanization is particularly preferred. here,
When employing sulfur vulcanization or organic sulfur vulcanization, it is necessary to use sulfur or sulfur of organic compounds, that is, 0.5 to 4 parts of the sulfur component per 100 parts of the rubber component in the rubber composition. This is suitable in terms of the storage stability of the vulcanized rubber composition and the heat aging resistance of the vulcanized rubber composition. That is, as mentioned above, in order to maintain stable adhesion, a sulfur component is used in a ratio of 4 to 8 parts in conventional bonding between a rubber composition and a substrate. According to the present invention, by interposing a cobalt or cobalt alloy thin film between the rubber composition and the substrate, the bonding strength thereof is improved, and excellent adhesive strength is exhibited even when the sulfur content is less than 4 parts, Therefore, it is possible to avoid heat aging of the rubber after vulcanization due to excessive use of sulfur, maintain good rubber physical properties such as tensile strength, breaking strength, and elongation, and obtain a rubber-based composite material with excellent durability. be able to.

The heating and compression bonding operations performed in the method for producing a rubber-based composite material of the present invention are performed at a temperature and pressure that does not damage the original shape of the substrate and the rubber composition to form a cobalt or cobalt alloy thin film. The rubber composition is brought into close contact with the rubber composition, and the activation thermal energy necessary to form a reaction between the cobalt or cobalt alloy thin film and the vulcanized rubber composition is supplied, and the rubber composition is further vulcanized. The purpose of this is to supply the activation thermal energy necessary for the activation, and the appropriate temperature and pressure for this purpose are appropriately selected depending on the type of substrate and rubber composition, and the range is not particularly limited.

As explained above, in the present invention, a thin film of cobalt or a cobalt alloy is deposited on the surface of a substrate, and then a rubber composition is heat-pressed and bonded by vulcanization onto the thin cobalt film. Even if the sulfur content used for vulcanization is low and a rubber composition containing no organic cobalt salt is used, the substrate and the rubber composition can be composited with very good bonding properties. Only a small amount of sulfur component is required to be added to the rubber composition for vulcanization and organic sulfur vulcanization, and furthermore, the use of organic cobalt salt can be reduced or eliminated; Various problems associated with the formulation of organic cobalt salts and the use of organic cobalt salts have been solved, and a rubber-based composite material with excellent durability can be obtained. material, shape,
Sizes can also be used.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1. Comparative Example 1] Base material: medium 25 mm x length 60 mm x thickness 2.3
Using violet 1 steel pieces (material 5S-41), aluminum pieces, and brass pieces, these base materials were cleaned and dried, and then the following dry plating methods A to C were applied to the surface of each base material. A Co thin film having the thickness shown in Table 2 was formed. The film thickness was measured using Talystep manufactured by Taylor Hobson.

A. After installing the vacuum evaporation method test piece (the above-mentioned base material) in a vacuum evaporation apparatus and setting the chamber to a vacuum level of 10-5 Torr or less,
A small amount of Ar gas is flowed into this to increase the degree of vacuum to 5 x 1.
After adjusting to 0''' Torr, the surface of the test piece was cleaned for 5 minutes with RF glow discharge from an RF high frequency power source.After cleaning, the RF glow discharge was stopped and a thin metal film (Co thin film) was applied to the surface of the test piece using a resistance heating method. was deposited.

B. Sputtering method Using a magnetron sputtering device, a test piece (the above-mentioned substrate material) was placed in the substrate holder in the device, and after making the chamber a vacuum of 10-5 Torr or less, a small amount of Ar gas was flowed into the chamber. After adjusting the degree of vacuum to 0.1 Torr, the surface of the test piece was cleaned for 5 minutes using 13.56 M) IzO high frequency glow discharge. After cleaning, the high-frequency glow discharge was stopped, a DC voltage of -600 μ 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-blating method: Place the test piece (the above-mentioned base material) in an ion-blating device, generate Ar plasma using a high-frequency power source according to the usual method, and evaporate the metal sample (Co) in that state by resistance heating. A metal thin film (Co thin film) was formed on the surface of the test piece.

After laminating the unvulcanized rubber composition (1) of the type shown in Table 1 below on the Co thin film of the substrate having the Co)] film obtained by the above dry plating method, the composition was pressurized at a temperature of 145°C for 40 minutes. The above rubber composition was vulcanized and bonded.

Table 1 Composite materials obtained by vulcanization adhesion of the above rubber compositions were subjected to a 90'' peel test using a tensile tester at a tensile rate of 50 mm/ll1n to evaluate adhesiveness.

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

The above adhesive evaluation results are shown in Table 2.

Table 2 Each m diameter represents the U cape % without destruction.

From the results in Table 2, it is clear that the adhesion properties of the rubber composite materials obtained by the method for manufacturing rubber composite materials (comparative example) in which the rubber composition is vulcanized and bonded directly onto the metal substrate are extremely poor. be. On the other hand, the adhesiveness of the rubber composite material obtained by the method for producing a rubber composite material (example) in which a cobalt m film is deposited on a metal substrate and then a rubber composition is vulcanized and bonded thereon is poor in adhesion to steel, aluminum, etc. It exhibits excellent adhesion to substrates made of any materials such as brass and brass, and furthermore, according to the method for producing a rubber-based composite material of the present invention, sufficient adhesion can be achieved without adding an organic cobalt salt to the rubber composition. It has been found that a rubber-based composite material having the following properties can be obtained. Further, according to the method for producing a rubber-based composite material of the present invention, a method for forming a thin film,
It was confirmed that a composite material with excellent adhesiveness could be obtained regardless of the thickness of the Co thin film.

(Example 2) In place of the metal base material of Example 1, polyarylate (manufactured by Unitika; trade name: U Polymer), polyamide (6I6
Nylon), polyether (manufactured by Engineering Blastisoku Co., Ltd.; trade name: Noryl), polysulfone (manufactured by Nissan Chemical Co., Ltd.; trade name: PE5), polycarbonate (25 mm in size)
A composite material was formed in the same manner as in Example 1, except that a plastic base material cut out into 60 mm long x 2 cranes thick and whose surface had been degreased with a solvent was used, and its adhesion was evaluated.

Table 3 shows the thickness and adhesion evaluation results of the Co11 film layer obtained during the formation of the above composite material.

Table 3 From the results shown in Table 3, even if the base material is changed from the metal in Example 1 to plastic, similar to Example 1, by adopting the manufacturing method of the rubber-based composite material of the present invention, it is possible to produce various types of rubber composite materials. C for plastic substrates.

A composite material with excellent adhesiveness can be obtained regardless of the thin film forming method and the thickness of the Con film, and furthermore, a composite material with excellent adhesiveness can be obtained without adding an organic cobalt salt to the rubber composition. was observed, confirming the effect of the present invention.

[Example 3. Comparative Example 2] A rubber-based composite material was produced in the same manner as in Example 1 and Comparative Example 1, except that the rubber compositions shown in Table 4 were used in place of the rubber compositions in Example 1 and Comparative Example 1. The adhesion was evaluated.

Table 5 shows the lI* thickness and adhesion evaluation results of the Coal film layer obtained during production of the above rubber-based composite material.

From the results in Table 5, it is clear that the method for producing a rubber-based composite material of the present invention exhibits excellent adhesion even when the rubber composition does not contain an organic cobalt salt. Regardless of the type of rubber composition, even if the amount of carbon is different from rubber compositions ■ to ■, or if rubber composition ■ is used which is different from these rubber compositions ■ to ■, It has been found that a composite material with excellent adhesive properties can be obtained, and as in Example 1, steel, aluminum,
It was confirmed that a rubber-based composite material with excellent adhesiveness could be obtained regardless of the method used to form the Coi film on any brass substrate.

[Example 4] A rubber-based composite material was produced in the same manner as in Example 3, except that the same plastic base material as that used in Example 2 was used in place of the metal base material in Example 3, and adhesive properties were determined. was evaluated.

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

3Z From the results in Table 6, it can be seen that by employing the manufacturing method of the rubber-based composite material of the present invention, even if the base material is replaced with plastic from the metal in Example 3, it is possible to produce a wide variety of plastic bases as in Example 3. A rubber-based composite material with excellent adhesiveness can be obtained regardless of the thin film forming method or the type of rubber composition, and the adhesiveness is also good even if the rubber composition does not contain an organic cobalt salt. was confirmed.

[Example 5. Comparative Example 3 A thin cobalt film of 40 people was deposited on the brass frame of Example 1 by vacuum evaporation, and then the rubber composition (1) shown in Table 1 was pressed at a temperature of 145° C. for 40 minutes. The adhesion of the rubber-based composite material produced by sulfur bonding and the adhesion after heating at 100°C for 24 hours were evaluated in the same manner as in Example 1. The degree of heat aging was evaluated based on the condition of the rubber composition.

Furthermore, for comparison, directly on the same brass frame as in Example 1,
A rubber system produced by heat-pressing and vulcanization bonding a cobalt naphthenate-containing rubber composition prepared by blending 2 parts of cobalt naphthenate in place of 2 parts of vegetable oil or mineral oil in Table 1 above in the same manner as above. The degree of thermal aging of the composite material was evaluated.

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

From the results in Table 7, it is clear that the rubber composite materials manufactured using rubber compositions containing cobalt naphthenate, which were conventionally considered to have good adhesive properties, exhibit a significant performance deterioration due to heat aging, whereas the performance of the rubber composite materials of the present invention It was found that the rubber-based composite material manufactured according to the manufacturing method showed almost no change in performance and had excellent heat aging prevention performance.

[Example 6. Comparative Example 4] Using a 1.21 m brass-plated steel cord with a strand structure of 3+6 as a base, the brass-plated steel cord surface was coated with the dry plating methods shown in Table 9 by the dry plating methods A to C above. A Co thin film was formed with a thickness of .

After laminating unvulcanized rubber compositions ① and ② of the types shown in Table 8 below on the Co thin film of the substrate having the Co thin film obtained by the above dry plating method, pressure was applied at a temperature of 145°C for 40 minutes. The above rubber composition was vulcanized and bonded.

Ill,) Table 8 (Note 6), (Note 7): Same as Table 1 (Note 8): N,N-dicyclohexyl-2-benzothiaprylsulfenamide The composite material obtained by vulcanization adhesion of the rubber composition (manufactured by Shinkosha Co., Ltd.) was subjected to a peel test at a tensile speed of 50 mm/min using a tensile tester to evaluate adhesiveness.

For further comparison, a rubber composition was vulcanized and bonded directly according to the above method without forming a cobalt thin film on the surface of the base material to produce a composite material without a cobalt thin film layer, and the adhesive properties were tested in the same manner as above. evaluated.

The above adhesive evaluation results are shown in Table 9.

Table 9 e9) In the table, R represents rubber failure, M/R represents the interface MIM between the substrate (brass plated steel Co-1)/rubber, and each value does not represent the percentage of failure or target hoof.

From the results in Table 9, it can be seen that according to the present invention, the thin film forming method, C
Regardless of the thickness of the ON film, even a rubber composition that does not contain an organic cobalt salt (rubber composition ■) has almost the same level of performance as a rubber composition that contains an organic cobalt salt (rubber composition ■). A rubber-based composite material with good adhesive strength and adhesion performance can be obtained, and on the other hand,
In the case of a comparative example in which a Con film was not deposited on a brass-plated steel cord base, it was confirmed that the adhesion was inferior in that no organic cobalt salt was added.

[Example 7. Comparative Example 5] Using the same brass-plated steel cord as in Example 6 as a substrate, a 400 Co thin film was formed on the surface of this substrate by the sputtering method described in B above, and then this Co
Example 6 Using the rubber compositions (1) and (2) shown in Table 8 above and the rubber compositions (2) to (xr) shown in Table 10 on the fiE film,
A rubber-based composite material was obtained by vulcanization and adhesion in the same manner as described above.

The thus obtained rubber-based composite material was evaluated for adhesion in the same manner as in Example 6, and for comparison, a rubber composition was applied directly to the base material surface according to the above method without forming a thin cobalt film. A composite material bonded with sulfur and without a cobalt thin film layer was produced, and its adhesion was evaluated in the same manner as above.

The above adhesive evaluation results are shown in Table 11.

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

The above measurement results are shown in Table 12.

From the results in Table 11, it is clear that when a rubber-based composite material is produced without depositing a CoFi film on a substrate, poor adhesion between the substrate and the rubber composition occurs depending on the type of rubber composition. It has been confirmed that, according to the method of the invention, a rubber composition with excellent adhesive properties can be obtained regardless of the type of rubber composition.

In addition, from the results in Table 12, as the amount of sulfur in the rubber composition increases, the retention of breaking strength and elongation at break before and after heating decreases. If salt is added, the retention of breaking strength and breaking elongation before and after heating will further decrease, and blending a large amount of sulfur into the rubber composition or adding organic cobalt salts will cause the rubber composition to deteriorate. Although it is confirmed that this is unfavorable for the material, as is clear from Table 11, when a Co3 film is formed, the amount of sulfur blended is small as in rubber compositions ■ and rubber compositions. In addition, the adhesion between the substrate and the rubber composition is excellent even without the addition of an organic cobalt salt as in rubber compositions (1) and (2) and (2), and therefore, according to the present invention, a large amount of sulfur component It has been found that it is possible to prevent the above-mentioned physical properties and heat aging resistance from deteriorating due to blending or the use of organic cobalt salts.

[Example 8. Comparative Example 6] Using the same substrate as in Example 7, approximately 400 particles were deposited on the surface of this substrate by the sputtering method in the same manner as in Example 7.
After forming an o thin film and then laminating the rubber composition (1) shown in Table 20 above on this co thin film, a rubber composite material was produced at 145° C. by changing the heating time, and the same procedure as in Example 7 was carried out. Adhesion was evaluated.

Furthermore, for comparison, a rubber composition was vulcanized and bonded directly according to the above method without forming a cobalt thin film on the surface of the base material to produce a composite material without a Cobal IJII film layer, and the adhesive properties were evaluated in the same manner as above. was evaluated.

The above adhesive evaluation results are shown in Table 13.

Table 13 From the results in Table 13, it can be seen that when a rubber composite material is manufactured using a rubber composition that does not contain cobalt naphthenate and without forming a Cog film on the substrate surface, as the vulcanization time increases, Although improvements in adhesion and adhesion performance are observed, satisfactory adhesion and adhesion performance cannot be obtained even after a vulcanization time of 100 minutes, whereas according to the method of the present invention, a vulcanization time of 20 minutes is not enough. It was confirmed that a rubber-based composite material with excellent adhesion strength and adhesion performance between the substrate and the rubber composition could be obtained even in just a few minutes.

[Example 9] Using the same substrate as in Example 7, about 400 carbon atoms were deposited on the surface of this substrate by sputtering in the same manner as in Example 7.
o A thin film is formed, and then rubber compositions (1) shown in Table 8 above, rubber compositions (2) and (2) shown in Table 10, and rubber compositions XI to 1 shown in Table 14 below are formed on this Con film. XIV
A rubber-based composite material was produced in the same manner as in Example 7 using each of these materials, and the adhesion properties before and after heat treatment at 100° C. for 24 hours were evaluated in the same manner as in Example 7.

The above adhesive evaluation results are shown in Table 15.

From the results in Table 15, it can be seen that according to the method of the present invention, the rubber composition (
It was confirmed that a rubber-based composite material with excellent adhesion performance between the substrate and the rubber composition could be obtained regardless of the amount of sulfur in the composition (all of which do not contain cobalt naphthenate). In addition, as the amount of sulfur added increases, the adhesive force and retention rate of the adhesion force decreases, and it is not preferable to add a large amount of sulfur to the rubber composition from the viewpoint of adhesion. It has been found that a rubber-based composite material having sufficient adhesion and excellent heat aging resistance can be obtained with approximately 1 part by weight per 100 parts by weight of the components.

[Example 10. Comparative Example 7] Using the same brass-plated steel cord substrate as in Example 6, a film thickness of about 0.1 μm was formed on the surface of this substrate by electrolytic plating.
A Co thin film was formed. Next is this G.

After laminating the rubber composition (1) shown in Table 8 and the rubber composition (2) shown in Table 10 on the thin film, vulcanization adhesion was performed in the same manner as in Example 6 to produce a rubber-based composite material. death,
A similar adhesion evaluation was conducted.

For further comparison, a rubber composition was vulcanized and bonded directly according to the above method without forming a cobalt thin film on the surface of the base material to produce a composite material without a cobalt thin film layer, and the adhesive properties were tested in the same manner as above. evaluated.

The above adhesive evaluation results are shown in Table 16.

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

Claims (1)

[Claims] 1. A method for manufacturing a rubber-based composite material formed by bonding a substrate and a rubber composition, in which a thin film of cobalt or a cobalt alloy is deposited on the surface of the substrate, and then a thin film of cobalt or a cobalt alloy is formed on the thin film of cobalt or a cobalt alloy. A method for producing a rubber-based composite material, which comprises heat-pressing and vulcanizing a rubber composition. 2. The method according to claim 1, wherein the substrate is metal. 3. The method according to claim 1 or 2, in which a rubber composition containing no organic cobalt salt is used as the rubber composition. 4. The method according to any one of claims 1 to 3, wherein the cobalt or cobalt alloy thin film is deposited by dry plating. 5. The method according to any one of claims 1 to 3, wherein the cobalt or cobalt alloy thin film is deposited by electroplating or electroless plating. 6. The method according to any one of claims 1 to 5, wherein the vulcanization is sulfur vulcanization or organic sulfur vulcanization. 7. The method according to claim 6, wherein the sulfur component is used in an amount of 0.5 to 4 parts by weight per 100 parts by weight of the rubber component in the rubber composition.