JP3511114B2 - Method for producing rubber-based composite material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of a rubber-based composite material which has excellent wet adhesion between a substrate and a rubber layer and can be vulcanized and bonded in a short time. About the method. 2. Description of the Related Art Generally, copper alloys such as brass are metals capable of obtaining a strong bond during rubber vulcanization by using a metal sulfidation reaction. In order to obtain a strong joint using these metals,
Compared with ordinary rubber, it is necessary to increase the amount of sulfur, accelerator and the like to be blended in the rubber in the case of sulfur and to select and blend a slower accelerator in the case of the accelerator. In addition, in order to obtain strong and stable adhesion to brass, it is necessary to compound an organic cobalt salt, an organic nickel salt typified by cobalt naphthenate, and the like in the rubber compounding. However, increasing the amount of sulfur and adding an organic cobalt salt or the like greatly affects the heat resistance of rubber. In particular, in the case of an anti-vibration rubber or the like which has many machines used in a wet state, it is not possible to mix an organic cobalt salt or the like for adhesion and to increase the amount of sulfur. In addition, if the price per unit is low for vibration isolating rubber,
It is necessary to shorten the vulcanization time to increase the productivity.
For this purpose, the vulcanization temperature is increased, the amount of the accelerator to be blended in the unvulcanized rubber is increased, or the blending is selected so as to increase the vulcanization rate. In such a system, even if a promoter for obtaining adhesion such as an organic cobalt salt is blended, stable adhesion with a brass-based metal cannot be obtained during vulcanization. Further, in order to produce a composite material such as a vibration-proof rubber, an adhesive which allows an adhesive reaction to proceed even in a short vulcanization time is often used. There is a problem, and it is desired to bond the base material and the rubber with good adhesiveness without using an adhesive. The applicant of the present invention has disclosed in
-87331, 62-246278, a method for producing a composite in which a base material / rubber is firmly joined at the time of vulcanization of unvulcanized rubber by forming a film of cobalt or a cobalt alloy on a base material by a dry plating method. Suggested.
Further, in Japanese Patent Application Laid-Open No. 1-290342, cobalt is oxidized at the time of forming a cobalt film and by a heat treatment after the film formation in order to improve the durability (wet heat deterioration resistance) after the production of the base material / rubber composite. . [0005] However, the base material and the rubber can be bonded without using an adhesive, and vulcanization bonding can be performed in a short period of time. In many cases, wet adhesion is an important adhesion factor, and a bonding method having high wet adhesion is desired. The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a method for producing a rubber-based composite material which has excellent wet adhesion between a base material and a rubber layer and can perform vulcanization bonding of rubber in a short time without using an adhesive. The present inventor has made intensive studies to achieve the above object, and as a result, manufactured a rubber-based composite material by bonding a base material such as metal to rubber. In doing so, a thin film of cobalt oxide represented by CoO _x (x is a positive number in the range of 0 to 1) is formed on the substrate surface, and N-cyclohexyl-2-benzothiazylsulfur is formed on the thin film. It has been found that it is effective to use phenamide (CZ) as a vulcanization accelerator and vulcanize and bond a rubber composition containing oil. That is, when a metal and a rubber are directly adhered to each other during vulcanization, it is known that a sulfenamide-based vulcanization accelerator is mixed into the rubber compound, but this system is more vulcanizable than other accelerators. Sulfurization rate is slow. However, when CZ is used, the vulcanization time is shortened. However, when CZ was used, even when a CoO _x thin film was formed on the surface of the substrate and joined, the wet adhesion was extremely poor. For this reason,
As a result of further study, it was found that when an oil such as a mineral oil was blended into the rubber composition, the wet adhesion was unexpectedly remarkably improved, and the present invention was accomplished. [0009] Accordingly, the present invention provides a method for forming a substrate on the surface of CoO.
_x After forming a thin film (x represents a positive number in the range of 0 to 1), N-cyclohexyl-2-benzothiazylsulfenamide is contained on the thin film as a vulcanization accelerator and oil is contained. A method for producing a rubber-based composite material, comprising forming a rubber composition layer formed as described above, and then vulcanizing the rubber composition. Hereinafter, the present invention will be described in more detail. In the method for producing a rubber-based composite material of the present invention, the type of the target substrate is not particularly limited, and the present invention is applicable to metals, ceramics, plastics, and the like. In this case, as the type of the metal substrate, for example, steel, stainless steel, titanium alloy, aluminum, aluminum alloy,
Examples include, but are not limited to, copper, copper alloys, zinc, zinc alloys, amorphous alloys, and the like. Various ceramics and plastics can be selected according to the purpose. The shape, size and the like of the substrate are appropriately selected according to the purpose. In the present invention, a CoO _x (x is a positive number in the range of 0 to 1) thin film is formed on the surface of the substrate to be bonded to the rubber. In this case, as a method of forming the CoO _x thin film, it can be formed by various vapor phase plating methods, or by forming a Co thin film and then oxidizing the Co thin film. Adopting a magnetron sputtering method or a facing target type sputtering method is preferable in that a CoO _x thin film which is simple and has excellent adhesion can be formed. When a CoO _x film is formed on the surface of a substrate, it is desirable to perform a cleaning process as a pre-treatment. The methods include solvent cleaning, ultrasonic cleaning,
Examples include wet methods such as acid and alkali cleaning, corona discharge treatment, atmospheric pressure plasma cleaning in an inert gas atmosphere, plasma cleaning in a vacuum, and dry methods such as reverse sputtering. By these processes, the base material and CoO
It is desirable to increase the adhesion to the _x film. Further, CoO is formed by the sputtering method.
_{When the x} film is formed, a method of mixing and reacting a gas having an oxidizing property and a gas for sputtering at the time of film formation is preferable, and a reactive sputtering method is generally employed.
In this case, oxygen, ozone,
Although those having oxygen atoms such as air and water can be used, they are not particularly limited. Helium, argon, or the like is used as the inert gas for sputtering, but argon, which is the least expensive, is preferable because it is used industrially. The degree of oxidation of the CoO _x film can be controlled by changing the mixing ratio of these gases, but depending on the size of the equipment used, the size of the cobalt target, the ultimate vacuum degree of the vacuum chamber, the difference in the sputtering method, etc. The degree of oxidation obtained varies. In this case, the change of the input voltage with respect to the DC power applied to the target at the ratio of various inert gases and the gas containing oxygen molecules at a predetermined degree of vacuum (gas pressure) is measured, and the input power versus the target and the target are measured. A voltage (input voltage) curve between the base materials is created, a transition point of the power at which the voltage is rapidly changed (increased) is obtained, and a method of forming a film by sputtering at a power equal to or higher than the transition point is adopted. Is preferred. In this case, there is a possibility that the adhesiveness may vary near the transition point. Therefore, it is preferable that the power transition point is at least 30 W or more, more preferably 5 W or more.
Sputtering is performed at a power of 0 W or more, more preferably 100 W or more. As a result, a cobalt oxide thin film having a high degree of oxidation of the cobalt oxide and excellent adhesiveness can be obtained. The other sputtering conditions can be the same as those known in the art, but the degree of vacuum is 1 mT
it is preferable that the Orr～1Torr, Although the mixing ratio of the gas having an oxygen molecule to the inert gas varies depending power applied, the inert gas as a volume ratio: O ₂
= 1: 0 to 1: 1. The thickness of the cobalt oxide film can be selected according to the purpose, but it is usually preferably from 10 to 100 μm from the viewpoint of productivity of the thin film, and particularly preferably from 50 to 1 μm. On the other hand, 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 alone or as a blend of two or more kinds are used. Can be used. Examples of the synthetic rubber include polyisoprene rubber (IR), polybutadiene rubber (BR), and polychloroprene rubber, which are homopolymers of conjugated diene compounds such as isoprene, butadiene, and chloroprene, and the conjugated diene compound and styrene, acrylonitrile, and vinyl. Styrene butadiene copolymer rubber (SBR) which is a copolymer with vinyl compounds such as pyridine, acrylic acid, methacrylic acid, 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,
Copolymers of olefins such as ethylene, propylene and isobutylene with diene compounds [eg isobutylene isoprene copolymer rubber (IIR)], copolymers of olefins with non-conjugated dienes (EPDM) [eg ethylene-propylene-cyclo Pentadiene terpolymer, ethylene propylene-5-ethylidene-2-norbornene terpolymer, ethylene propylene-1,4-hexadiene terpolymer], polyalkenamer obtained by ring-opening polymerization of cycloolefin [ For example, polypentenamer], rubber obtained by ring-opening polymerization of an oxirane ring [for example, polyepichlorohydrin rubber capable of sulfur vulcanization], and polypropylene oxide rubber are included. Further, halides of the various rubbers, for example, chlorinated isobutylene isoprene copolymer rubber (Cl-IIR), brominated isobutylene isoprene copolymer rubber (Br-IIR), and the like are also included. Further, a ring-opened polymer of norbornene may be used. Moreover,
As the blended rubber, a blend of a saturated elastic material such as epichlorohydrin rubber, polypropylene oxide rubber, chlorosulfonated polyethylene, or the like with the above rubber can also be used. The rubber composition used in the present invention further comprises sulfur, an organic sulfur compound, and other crosslinking agents.
Preferably from 0.01 to 100 parts by weight (the same applies hereinafter).
10 parts, more preferably 0.1 to 6 parts, is blended, and in the present invention, CZ (N-cyclohexyl-2-benzothiazylsulfenamide) is blended as a vulcanization accelerator. In this case, the compounding amount of CZ is preferably 0.01 to 10 parts, particularly preferably 0.1 to 5 parts with respect to 100 parts of the rubber component. In the present invention, the vulcanization time is shortened by using CZ. be able to. Furthermore, the rubber composition of the present invention includes mineral oils such as paraffinic, naphthenic, aromatic process oils, copolymers of ethylene-α-olefins, paraffin wax, liquid paraffin, castor oil, cottonseed oil, and the like. Linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil,
An oil such as a vegetable oil such as peanut oil is blended therein, whereby the wet adhesion to rubber on the CoO _x thin film accompanying the use of CZ can be improved. The amount of the oil is preferably 3 to 50 parts, more preferably 4 to 10 parts, per 100 parts of the rubber component. If the amount of the oil is too small, the effect of improving the wet heat adhesion is small, and if the amount is too large, the spring characteristics of the rubber itself greatly change. In particular, in the case of a vibration-proof rubber, tan δ, which is important for damping vibration, tends to greatly change. The rubber component may be further used in a conventional manner according to the purpose and application, for example, fillers such as carbon black, silica, calcium carbonate, calcium sulfate, clay and mica, and vulcanization accelerators such as zinc white and stearic acid. A rubber composition can be prepared by adding an auxiliary agent or the like. In the present invention, it is not necessary to particularly add an organic cobalt salt as a vulcanization adhesion promoter between the partially cobalt oxide and the rubber. The bonding between the rubber composition and the CoO _x thin film on the surface of the substrate is performed by heating and pressing the rubber composition on the thin film and bonding them by vulcanization. Organic sulfur vulcanization with an organic sulfur compound such as dithiomorpholine or thiuram vulcanization is employed, and vulcanization can be performed according to a conventional method. Among these, the method using sulfur vulcanization is particularly preferred. In this case, the compounding amount of sulfur in the sulfur or the organic sulfur compound is preferably 0.5 to 7 parts, particularly preferably 1 to 6 parts with respect to 100 parts of the rubber component. In the method of the present invention, the above sulfur is, for example, 5 to 6
After performing vulcanization bonding for a long time with a rubber composition blended in a large amount such as a part, even if a peeling test is performed in a low temperature atmosphere of, for example, about −60 ° C., no destruction in the CoO _x thin film occurs
The base material and the rubber can be strongly bonded, and therefore the method of the present invention requires a bonding strength between the base material such as a metal and the rubber,
Manufacture of various rubber products and parts such as power transmission belts, conveyor belts, rubber composites using fibrous metal as the core such as hoses, anti-vibration rubber, anti-vibration materials, rubber crawlers, rubber screens, rubber rolls, etc. Can be widely applied. In particular, the present invention is effective in producing vibration-proof rubber and the like because of good wet adhesion. According to the present invention, the wet adhesion between the base material and the rubber layer is excellent, the vulcanization time is short, and strong bonding can be performed without using an adhesive. is there. EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. [Examples and Comparative Examples] 10 × 75 as a substrate
Using an aluminum test piece of × 0.5 mm, the surface was first washed with acetone, and then a high-frequency 13.56 MHz,
A vacuum argon plasma treatment was performed at 0 W for 5 minutes. On the substrate, a CoO _x film was formed with a target thickness of 500 ° by magnetron sputtering. The sputtering conditions were as follows: 18 ml / min of argon as a gas for sputtering, and 6 ml / min of oxygen for oxidization were flown into the sputtering apparatus, the gas pressure was 5 mTorr, and the target input power was 800 W.
For 30 seconds. Next, the adhesiveness was examined using the compounded rubber compositions shown in Table 1. For the vulcanization time, the optimum vulcanization time after compounding was measured with a curast meter, and the time was calculated as 2
The multiplied time was the vulcanization time of the test piece at 150 ° C. Table 2 shows the adhesion data. [Table 1] [Table 2] In the dry bonding, a rubber-based composite material obtained by vulcanizing and bonding the above rubber composition was subjected to a 90 ° peel test at room temperature at a tensile strength of 50 mm / min using a tensile tester.
Performed in air. In the wet adhesion, in the above adhesion test, water was dropped on the rubber-substrate interface, and a 90-degree peel test was performed in the presence of water at the interface. From the results shown in Table 1, the vulcanization accelerator A, ie, CZ
When vulcanization is used, the vulcanization rate is high, which is advantageous for producing a small product such as a vibration-proof rubber. However, as can be seen from the results of Formulation No. A in Table 2, the system without oil has poor wet adhesion (wet adhesion). However, it is recognized that the wet adhesiveness is improved by adding oil to this to a certain extent or more.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C08L 21/00 C08L 21/00 91/00 91/00 // C08L 21:00 21:00 (56) References JP 7 JP-A-5-3783 (JP, A) JP-A-4-202233 (JP, A) JP-A-3-220241 (JP, A) JP-A-62-189117 (JP, A) JP-A-62-87311 (JP, A) JP-A-6-256585 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 5/12 B32B 15 / 06,25 / 04 C08L ⁷ /00-21/00

Claims (1)

(57) Claims 1. After forming a CoOx (x is a positive number in the range of 0 to 1) thin film on the surface of a substrate, N-cyclohexyl-2-benzo is formed on the thin film. While containing thiazyl sulfenamide as a vulcanization accelerator, a rubber composition layer containing oil is formed, and then the rubber composition is vulcanized.
A method for producing a rubber-based composite material, comprising:
Is 3-5 based on 100 parts by weight of the rubber component in the rubber composition.
A method for producing a rubber-based composite material, which is 0 parts by weight .