JP2917382B2 - Rubber compounding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to bonding of a rubber composition to a base material using a copper alloy thin film formed on the surface of the base material, particularly in a high-temperature and high-humidity environment. The present invention relates to a method for compounding rubber which gives a rubber-adhesive composite having excellent durability.

[Problems to be solved by conventional technology and invention]

Rubber-based composite materials have a wide range of applications such as automobile parts such as tires, conveyor belts, belts, vibration-isolating rubbers, hoses, industrial supplies, electronic parts, and sports goods. Has an industrially important application field represented by a tire, an anti-vibration rubber, a belt and the like.

Conventionally, such a rubber-based composite material is manufactured by applying a brass (copper-zinc alloy) plating or zinc plating by a wet plating method or a method of applying a rubber composition by applying an adhesive to a base material, Methods such as vulcanization bonding of rubber compositions have been employed.

Among them, the method using an adhesive generally has a thick coating film of several to tens of μm and is brittle with a coin. In the case of a thin cord or the like whose material is greatly deformed, there is a problem that the adhesive portion is broken and cannot be used for such a purpose.

On the other hand, in the case of brass or zinc plating, there is a disadvantage in that a rubber composition containing an organic cobalt salt or the like which is an adhesion promoter must be used in order to obtain a stable and highly productive bond, which is soft and flexible. is there. In the case of tire cords and the like, in addition to excellent initial adhesion performance, a plating material with excellent corrosion resistance and heat resistance is required, so brass plating cords are used.However, the running conditions of car tires are severe, In an environment of high humidity, there is a problem that the adhesive strength of the adhesive surface is reduced.

Furthermore, the zinc brass plating by the electrolytic method conventionally used industrially generates a waste liquid, and the treatment of the waste liquid becomes a problem.

On the other hand, the present inventors have previously proposed that a base material and a rubber composition be bonded to each other through a zinc, copper, cobalt or cobalt alloy plating film formed by a dry plating method (Japanese Patent Application Laid-Open No. 62-87311). JP-A-62-246278.

However, although the bonding and compounding of rubber according to these proposals gives excellent bonding performance and eliminates the problem of waste liquid, in the case of zinc and brass, the rubber composition containing the above-mentioned organic cobalt salt is used. In addition, there is room for improvement in the decrease in the adhesive strength in the high-temperature and high-humidity environment described above. On the other hand, in the case of cobalt or cobalt alloy plating, cobalt is expensive and disadvantageous in cost, and because cobalt or cobalt alloy plating is hard and poor in toughness, when it is applied to a substrate such as a thin cord, wire drawing is performed. In addition, since cobalt is a ferromagnetic material, there is a problem that there is a limit to a film forming rate and a target thickness in a magnetron sputtering film forming method.

The present invention has been made in view of the above circumstances, and in a method of bonding and bonding a base material and a rubber composition via a metal thin film, the base material and the rubber composition are strongly bonded without adding an organic cobalt salt to the rubber composition. The rubber-adhesive composite that adheres to rubber and has excellent adhesive durability in high-temperature and high-humidity environments and, when combined with thin cords, has excellent workability during wire drawing. It is an object of the present invention to provide a method of compounding a given rubber.

[Means and actions for solving the problem]

The present inventors have conducted intensive studies to achieve the above object, and as a result, a copper alloy thin film selected from a copper alloy containing aluminum, a copper alloy containing aluminum and tin, and a copper alloy containing aluminum and nickel. When formed on the surface of the base material, such a base material and the rubber composition are firmly bonded and complexed without using an organic cobalt salt or the like which is an adhesion promoter, and have an adhesive property under high temperature and high humidity. It has been found that the drop is extremely small, the adhesion durability is excellent, and the copper alloy thin film is soft, and even when compounded with a thin cord or the like, the workability at the time of drawing is good, and the present invention It is what led to.

Accordingly, the present invention provides an adhesive composite of a rubber composition and a substrate having a surface formed with a copper alloy thin film selected from a copper alloy containing aluminum, a copper alloy containing aluminum and tin, and a copper alloy containing aluminum and nickel. And a method of compounding rubber.

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

In the method of compounding rubber of the present invention, the type of the target substrate is not particularly limited, and is applicable to metals, ceramics, plastics, FRP, and the like. In this case, as the type of the metal substrate, for example, steel, stainless steel, titanium, titanium alloy, aluminum, aluminum alloy,
Examples include, but are not limited to, copper, copper alloys, zinc, zinc alloys, amorphous alloys, and the like. Also, various types of ceramics, plastics, and FRPs can be set according to the purpose.

The shape and size of the base material are appropriately selected depending on the purpose, for example, steel wire, steel cord,
Steel tire cords, steel cables, steel strands, steel rods, steel plates, steel filaments, etc. (hereinafter collectively referred to as steel cords), metal plates and metal appliances, plastic plates, FRP plates and the like are used.

The rubber compounding method of the present invention is a method of compounding these base materials and a rubber composition, and the obtained rubber composite has an adhesive property between the base material and the rubber, especially in a high temperature and high humidity environment. Is stable and has excellent workability during stretching.
For example, various rubber products such as tires, power transmission belts, conveyor belts, rubber-based composite materials using fibrous metal as the core material such as rubber, vibration-isolating rubber, seismic isolation materials, rubber crawlers, rubber screens, rubber rolls, and OA parts Can be widely applied to the manufacture of products.

Before forming a copper alloy thin film described later on the above-described base material,
Pretreatment is performed by cleaning the surface of the equipment by a wet method such as solvent cleaning, ultrasonic cleaning, acid or alkali cleaning, by plasma cleaning (bombard) performed in vacuum, or by a dry method such as reverse sputtering. It is desirable to improve the adhesion between the copper alloy thin film and the base material by performing the treatment.

In the present invention, the metal thin film formed on the surface of the base material is a copper alloy containing aluminum, a copper alloy containing aluminum and tin, or a copper alloy containing aluminum and nickel.

Here, as the composition of the alloy, aluminum is 5
-40 at%, especially 10-30 at%, tin 0-25 at%,
In particular, 5 to 15 atomic%, nickel is 0 to 30 atomic%, particularly 5 to 5 atomic%.
Preferably, the content is 25 at% and the balance is copper, and in addition, the total amount of aluminum and tin or the total amount of aluminum and nickel is preferably 40 at% or less. If the content is outside the above range, sufficient adhesive strength to a rubber composition containing no organic cobalt salt may not be produced.

In the dry plating method using an alloy target, these copper alloy plating thin films can be alloyed at the same time as being formed on the substrate, but in addition, an aluminum plating film can be formed on the copper substrate or copper plating. Alternatively, an aluminum and tin plating film or an aluminum and nickel plating film may be separately formed on a copper substrate or copper plating or by an alloy, and then alloyed by thermal diffusion.

The thickness of the copper alloy thin film can be appropriately selected according to the purpose, but is usually preferably 10 to 100 μm from the viewpoint of productivity of the thin film, and particularly preferably 50 to 1 μm.

Aluminum is an electrochemically low-potential substance and has a low standard electrode potential. For this reason, generally, electroplating of a water electrolyte is impossible, and electroplating is possible when a special organic solvent is used. The same applies to aluminum alloys.
Therefore, in order to easily form a copper alloy plating containing aluminum, it is preferable to employ a dry plating method.

Therefore, as a method for forming a copper alloy thin film, wet plating of aluminum is difficult as described above, so it is preferable to employ a dry plating method entirely or partially, for example, a vacuum deposition method, an ion plating method. , DC and high-frequency magnetron sputtering, two-pole sputtering, high-frequency sputtering, arc discharge sputtering, electron cyclotron resonance (ECR) plasma, and the like. Among these dry plating methods, ion plating, DC and high frequency magnetron sputtering, bipolar sputtering, and high frequency sputtering are preferred.

Next, as a rubber component in a rubber composition for obtaining a composite material of a base material and a rubber, natural rubber (NR) and a synthetic rubber having a carbon-carbon double bond in a 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. The conjugated diene compound is combined with styrene, acrylonitrile, and vinylpyridine. Styrene-butadiene copolymer rubber (SBR) which is a copolymer with vinyl compounds such as acrylic acid, methacrylic acid, alkyl acrylates and alkyl methacrylates, vinyl pyridine butadiene styrene copolymer rubber, acrylonitrile butadiene copolymer rubber, acrylic acid Butadiene copolymer rubber, methacrylate butadiene copolymer rubber, methyl acrylate 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 (eg, methyl methacrylate butadiene copolymer rubber) EPDM) [for example, ethylene-propylene-
Cyclopentadiene terpolymer, ethylene propylene-5-ethylidene-2-norbornene terpolymer, ethylene propylene-1,4-hexadiene terpolymer], and a polyalkenamer obtained by ring-opening polymerization of a cycloolefin [For example, polypentenamer], rubber obtained by ring-opening polymerization of oxirane ring [for example, polyepichlorohydrin rubber capable of sulfur vulcanization], and polypropylene oxide rubber. Also included are halides of the various rubbers, for example, chlorinated isobutylene isoprene copolymer rubber (Cl-IIR), brominated isobutylene isoprene copolymer rubber (Br-IIR), and the like. Further, a ring-opened polymer of norbornene may be used. Still further, as the blend rubber, a saturated elastic material such as epichlorohydrin rubber, polypropylene oxide rubber, chlorsulfonated polyethylene, or the like may be blended with the above rubber to be used.

The rubber component further according to a conventional method, carbon black, silica, calcium carbonate depending on the purpose, use, etc.,
Fillers such as calcium sulfate, clay, mica, mineral oil,
Softeners such as vegetable oils, sulfur and other crosslinking agents, vulcanization accelerators,
A rubber composition can be prepared by adding a vulcanization accelerator such as zinc white and stearic acid.

In the present invention, an organic cobalt salt or the like which is a vulcanization adhesion promoter between the copper alloy thin film and the rubber is not usually required, but may be added in some cases.

The composite of the rubber composition and the copper alloy thin film on the surface of the substrate can be obtained by heating and pressing the rubber composition on the copper alloy thin film and vulcanizing and bonding.

Here, in addition to sulfur vulcanization, an organic sulfur vulcanization using an organic sulfur compound such as dithiomorpholine or thiuram vulcanization is adopted as the vulcanization method, and vulcanization can be performed according to a conventional method. Among these, the method by sulfur vulcanization is particularly preferred. In this case, the compounding amount of sulfur in the sulfur or the organic sulfur compound may be 0.5 to 7 parts by weight, preferably 1 to 6 parts by weight based on 100 parts by weight of the rubber component.

〔The invention's effect〕

As described above, the method of compounding rubber according to the present invention comprises:
A rubber that does not use an organic cobalt salt by combining a base material and a rubber with a copper alloy thin film selected from a copper alloy containing aluminum, a copper alloy containing aluminum and tin, and a copper alloy containing aluminum and nickel. The composition can be compounded, and the obtained rubber-adhesive composite has excellent adhesive durability especially at high temperature and high humidity. In addition, since the copper alloy thin film is soft, rubber adhesion with a metal cord or the like is achieved. The composite is excellent in workability such as wire drawing.

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

(Examples, Comparative Examples)

Brass-plated steel cord (diameter:
Using 0.18 mm, twisted structure: 3 + 9), the surface of the steel cord was subjected to argon plasma treatment at a high frequency of 13.56 MHz and a power of 100 W for 3 minutes.

A thin film having an alloy composition shown in Table 2 having a thickness of about 500 mm was formed on the steel cord subjected to the above treatment by a DC magnetron sputtering method using a Cu-Al-based alloy target. Here, sputtering conditions are Ar gas pressure 5 mmTor.
r, power was 0.5A × 400V for 30 seconds. In addition, the alloy composition measured the alloy thin film formed on the glass substrate by the emission spectrometry.

Next, the above cord was bonded to an unvulcanized rubber composition having the composition shown in Table 1 and then vulcanized at 145 ° C. for 40 minutes.

The vulcanized adhesive sample thus obtained was subjected to a 180 ° peel test at a tensile speed of 50 mm / min using a tensile tester, and the adhesive force was measured, and the peel surface was observed. Was evaluated.

Adhesive performance R (%): Rubber adhesion area% of cord after peel test
(Rubber cohesion failure rate) F / R (%): Peeling area% at interface between rubber layer and alloy thin film after peeling test (fracture rate at cord-rubber interface) In comparison with Cu-Zn alloy of comparative example Were bonded using a rubber composition obtained by adding an organic cobalt salt (cobalt naphthenate) to the rubber composition shown in Table 1.

 The results are shown in Table 2.

From the results in Table 2, it can be seen that Cu-Al, Cu-Al-Sn and Cu-Al-
It is recognized that any alloy thin film system of Ni gives good adhesive performance using a rubber composition containing no organic cobalt salt.

Next, each sample of Examples 2, 3, 6, 7, 9, 10 and Comparative Example in Table 2 was left in a high-temperature, high-humidity atmosphere of 80 ° C. and 95% RH, and And the change over time of the adhesive performance in the above atmosphere were measured.

 The results are shown in Table 3.

From the results in Table 3, it can be seen that Cu-Al, Cu-Al-Sn and Cu-Al-
It is recognized that any of the alloy thin films of Ni gives a composite material excellent in adhesion durability at a higher temperature and a higher humidity than the Cu-Zn alloy thin film of the comparative example.

The softness of the sample was measured by measuring the Vickers hardness (Hv) with a measuring load of 0.5 kgf using a microhardness tester on a sample in which an alloy thin film having a thickness of about 4 μm was formed on a substrate (brass plate) by sputtering. The processability of the product including the drawability was evaluated. In this case, processing is difficult if the value of Vickers hardness is large, and processing is easy if the value is small.
The results are shown in Table 4.

As shown in Table 4, Cu-Zn is soft and excellent in workability, but as described above, durability is poor at high temperature and high humidity, whereas Co is hard and poor in workability. In contrast, Cu-Al,
Cu-Al-Sn and Cu-Al-Ni alloys are slightly harder than Cu-Zn but softer than Co, and it is recognized that they have both workability and durability.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B32B 15/06 C08J 5/12 B29D 30/38

Claims (1)

(57) [Claims] 1. A rubber composition is bonded to a base material having a copper alloy thin film selected from a copper alloy containing aluminum, a copper alloy containing aluminum and tin, and a copper alloy containing aluminum and nickel formed on a surface thereof. A method for compounding rubber, comprising compounding.