JPH03197135A - Rubber laminate - Google Patents

Abstract

PURPOSE:To obtain a laminate wherein silicon rubber and organic rubber having an excellent heat resistance, cold resistance, and weatherability are bonded firmly to each other by superimposing and vulcanizing an unvulcanized rubber layer containing silicone rubber and an unvulcanized rubber layer containing organic rubber, and blending specific organopolysiloxane on the one layer in a specific quantity. CONSTITUTION:The rubber laminate is a laminate wherein an unvulcanized rubber layer A containing silicone rubber and an unvulanized rubber layer B containing organic rubber are superimposed and vulcanized. On the one layer, 3 - 500 of polymerization degree of organopolysiloxane C shown by an average unit formula I is blended at 0.1 - 20pts.wt. relative to 100pts.wt. of rubber. When the addition quantity of organopolysiloxane is too less, sufficient adhesion can not be obtained, on the contrary, it is too much, the characteristics of the silicone rubber and organic rubber are damaged. The layer containing the silicone rubber and the layer containing the organic rubber are bonded firmly by vulcanization without using any intermediate layer or adhesive agent. In the formula, R shows a substituted or non-substituted monovalent hydrocarbon radical, and 5 - 50mol.% in R is a vinyl group, and (a) denotes a number of 0 < a < 4.

Description

[Detailed description of the invention] a. Industrial application field The present invention relates to a laminate of silicone rubber and organic rubber,
More specifically, the present invention relates to a rubber laminate in which a layer containing silicone rubber and a layer containing organic rubber are firmly adhered by vulcanization without using an intermediate layer or an adhesive.

Furthermore, the present invention provides a layer containing a mixture of silicone rubber and organic rubber (hereinafter referred to as silicone rubber composite material);
Regarding a laminate with a layer containing an organic rubber vulcanizable with an organic peroxide, the layer containing a silicone rubber composite material and the layer containing an organic rubber vulcanizable with an organic peroxide are bonded together using an adhesive. The present invention relates to a rubber laminate that adheres firmly through vulcanization without any heat aging and maintains excellent adhesive strength even after heat aging.

b. Prior art In recent years, the requirements for the performance of rubber materials have become stricter year by year, and the types of rubber materials used have also changed. Among rubbers, silicone rubber has outstanding performance compared to other rubbers in terms of heat resistance, cold resistance, and weather resistance, and its demand is increasing year by year in industrial products, automobiles, aircraft, medical fields, etc. ing.

However, silicone rubber is more expensive than organic rubber and has inferior mechanical strength, so the fields in which it can be used have been limited. In order to simultaneously satisfy the contradictory demands of taking advantage of the advantages of silicone rubber and compensating for its disadvantages,
It is difficult to deal with this problem using silicone rubber alone, and attempts have been made to mix silicone rubber and organic rubber or to laminate them.

However, when silicone rubber and organic rubber are laminated, it has been difficult to obtain a laminate in which silicone rubber and organic rubber are firmly adhered because silicone rubber and organic rubber are difficult to co-crosslink.

Also, Special Publication No. 57-26233, Special Publication No. 61-2
Publication No. 5544 discloses a method in which a blend of the organic rubber and silicone rubber is inserted into a plurality of intermediate layers when adhering silicone rubber and organic rubber. However, there has been a desire for a laminate in which silicone rubber and organic rubber are firmly adhered, which can be easily produced without using an intermediate layer.

In addition, in recent years, as the rubber materials used have changed, composite materials made by mixing different materials have been used to overcome the limitations of a single material.

JP-A-63-72745, JP-A-1-10363
6, JP-A-1-272648, etc., in order to improve the drawbacks of silicone rubber, ``compounding silicone rubber by mixing it with various organic rubbers has been considered.

However, when considering various rubber parts, simply mixing and compounding silicone rubber and organic rubber is not sufficient in terms of performance, and lamination with other materials is required.

However, as mentioned above, the adhesion between silicone rubber and organic rubber is generally poor, and the adhesion of silicone rubber composites with organic rubber other than the organic rubber used in the composite is not sufficient. The problem is that the adhesive strength decreases after the laminate is left in a high-temperature atmosphere, and a solution has been sought.

C0 Problems to be Solved by the Invention An object of the present invention is to provide a laminate in which silicone rubber and organic rubber, which are excellent in heat resistance, cold resistance, and weather resistance, are firmly adhered.

Furthermore, another object of the present invention is to provide a laminate in which a silicone rubber composite material and an organic rubber are firmly adhered.

d. Means for Solving the Problems The present invention comprises an unvulcanized rubber layer (A) containing silicone rubber;
A rubber laminate obtained by laminating and vulcanizing an unvulcanized rubber layer (B) containing organic rubber, comprising the above (A) or (
B) An organopolysiloxane (C) having a degree of polymerization of 3 to 500 and represented by the following average unit formula (1) in at least one of the layers.
Rubber laminate RaSiO, a-a>yz, characterized in that 0.1 to 20 parts by weight are blended with respect to 100 parts by weight of rubber.
-----(1) [In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group, 5 to 50 mol% of R is a vinyl group, and a is a number where Q<a<4 It is. ], and the unvulcanized rubber layer (A) is a layer containing a mixture of silicone rubber and organic rubber that can be vulcanized with an organic peroxide and an organic peroxide, and the unvulcanized rubber The above rubber laminate, wherein the layer (B) is a layer containing an organic rubber and an organic peroxide different from the organic rubber contained in the layer (A) which is vulcanizable with an organic peroxide. It is something.

The present invention will be explained in more detail below.

The rubber layer (A) of the present invention is an unvulcanized rubber layer containing silicone rubber.

The above silicone rubber has the following average unit formula (■): R'
a Si0. 4-a, yz ------・-・-・
-...(I[) [wherein R' is substituted or unsubstituted 1]
0.02 to 5 mol% of R'
is a vinyl group, and a is a number from 1.900 to 2.004.

], is an organopolysiloxane with a degree of polymerization of 500 to 10,000, and is mainly linear, but
Part of it may have a branched or three-dimensional structure. Further, it may be a homopolymer, a copolymer or a mixture thereof. Examples of substituted or unsubstituted monovalent hydrocarbon groups of this organopolysiloxane include methyl group, ethyl group, propyl group, phenyl group, vinyl group, and substituted hydrocarbon groups obtained by substituting these with halogen atoms or cyano groups. However, it is necessary that 0.02 to 5 mol% of these hydrocarbon groups directly bonded to silicon in the molecule be vinyl groups.

In addition to the above-mentioned silicone rubber, the rubber layer (A) can contain various property improvers such as silica and processing aids, which are usually added to silicone rubber.

The rubber layer (B) of the present invention is an unvulcanized rubber layer containing organic rubber.

The above-mentioned organic rubber may be any rubber that can be vulcanized with peroxide, and is a polymer having an unsaturated group or a group that is easily abstracted by radicals such as tertiary carbon, bromine, iodine, or active hydrogen group. Examples include the following polymers.

IRSBRSSBR, NBRSCR, diene rubber such as natural rubber, ethylene/α-olefin copolymer rubber, acrylic rubber, copolymer rubber of ethylene and/or vinyl acetate and acrylic ester, epihalohydrin and allyl glycidyl ether, etc. Copolymer rubber with saturated group-containing rubber, halogenated or chlorosulfonated polyethylene, copolymer of ethylene and vinyl acetate, fluororubber with bromine, iodine, tertiary carbon and/or unsaturated double bond can be mentioned.

In the present invention, organopolysiloxane (C) is blended into at least one of the rubber layer (A) and the rubber layer (B).

The above organopolysiloxane (C) has an average unit formula ()
: % Formula % (1) [In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group, 5 to 50 mol% of R is a vinyl group, and a is O<a<
The number is 4. ] and has a degree of polymerization of 3 to 500.

Monovalent hydrocarbon groups other than substituted or unsubstituted vinyl groups in organopolysiloxane (C) include methyl groups, ethyl groups, propyl groups, phenyl groups, and hydrocarbon groups substituted with these groups with halogen atoms or cyano groups. etc. can be mentioned. The vinyl group directly bonded to the silicon atom accounts for 5 to 50 mol%, preferably 10 to 50 mol% of the hydrocarbon group bonded to the silicon atom.

If the amount of vinyl groups is too large or too small, sufficient adhesive strength cannot be obtained. Also, organopolysiloxane (C
) If the degree of polymerization is too high, sufficient adhesive strength will not be obtained, and if it is too low, it will easily volatilize and be difficult to handle.

Organopolysiloxane (C) is mainly linear or cyclic, but some of it may be branched,
The amount of organopolysiloxane (C) added, which may be a copolymer or a mixture thereof, is 0.1 to 20 parts by weight, preferably 0.5 to IO, per 100 parts by weight of silicone rubber or organic rubber. Parts by weight range. If the amount of organopolysiloxane added is too small, sufficient adhesion cannot be obtained, and if it is too large, the properties of the silicone rubber or organic rubber will be impaired.

In the present invention, the rubber layer (A) and the rubber layer (B) are superimposed and vulcanized.

For vulcanization, organic peroxides can preferably be used as crosslinking agents (vulcanizing agents) for silicone rubbers and organic rubbers, examples of which include the following.

Acyl peroxides such as dibenzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2
, 5-di(t-butylperoxy)hexane, 2.5-
Dimethyl-2,5-di(t-butylperoxy)hexyne-3,α,α'-bis(1-butylperoxy)p-
These include alkyl peroxides such as diisopropylbenzene, peroxy esters such as L-butylperoxyacetate, t-butylperoxyisopropyl carbonate, and t-butylperoxybenzoate.

These may be used alone or in a mixture of two or more. These organic peroxides are used in an amount of 0.1 to 10 parts by weight per 100 parts by weight of rubber (silicone rubber or organic rubber).

In the present invention, it is also possible to use an organic peroxide crosslinking aid.

Examples of crosslinking aids include the following.

polyfunctional allyl compounds such as triallyl isocyanurate and triallyl cyanurate, polyfunctional acrylic or methacrylic acid esters such as ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and polyethylene glycol diacrylate, m-phenylene bismaleimide, oxime compounds, Sulfur compounds, 1. Polyfunctional polymers such as 2-polybutadiene.

In addition to the organic rubber and the crosslinking agent, the rubber layer (B) contains compounding agents that are usually used as compounding agents for organic rubber, such as:
Carbon black, silica, calcium carbonate, magnesium carbonate, zinc carbonate, aluminum silicate, calcium silicate, magnesium silicate, metal oxides, glass flakes, glass fibers, and other granular, platy, and fibrous inorganic and organic fillers. reinforcing materials, fillers, paraffinic oils, naphthenic oils, aromatic oils, softening agents such as liquid polymers, phthalate esters, adipate esters, maleate esters, fumarate esters, phosphate esters, etc. Plasticizers, processing aids such as stearic acid, sodium stearate, fatty acid esters, and fatty acid amides, lubricants, various pigments, coupling agents, flame retardants, and the like can be blended.

The rubber laminate of the present invention can be produced by molding simultaneously or at different times using a press, transfer injection molding, or extrusion molding machine, and by stacking and simultaneously vulcanizing.

The vulcanization conditions are not particularly limited, and the vulcanization temperature and vulcanization time are determined by the type of organic peroxide used.
It is usually carried out under conditions of 100 to 200°C and 1 to 60 minutes.

In the present invention, it is also possible to shorten the primary vulcanization time and improve the adhesive strength by heat-treating the rubber laminate, if necessary.

The invention of claim (2), which is one aspect of the present invention, will be described below.

The rubber layer (A) of claim (2) is a layer containing a mixture of silicone rubber and organic rubber that can be vulcanized with an organic peroxide (hereinafter referred to as a silicone rubber composite) and an organic peroxide. be.

The silicone rubber is the same as the silicone rubber of claim (1), and the organic rubber is the same as the organic rubber contained in the rubber layer (B) in the invention of claim (1). It is.

Further, the organic peroxide is the same as the organic peroxide used as a crosslinking agent for silicone rubber and organic rubber in the invention of claim (1).

The mixing ratio of silicone rubber and organic rubber in the silicone rubber composite material is 3 to 70% by weight of silicone rubber and 97 to 30% by weight of organic rubber, preferably 3 to 5% by weight of silicone rubber.
0% by weight, organic rubber 97-50% by weight.

The manufacturing method for silicone rubber composites is to mix silicone rubber and organic rubber in a roll, Banbury mixer, or kneader.
Examples include a method of mixing in an internal mixer such as a method of mixing, a method of crosslinking the silicone rubber by reaction during mixing, and a method of graft polymerizing an organic rubber monomer in the presence of a silicone rubber emulsion. The form of the obtained silicone rubber composite material is preferably one in which silicone rubber particles having a particle size of 20 μm or less are dispersed in an organic rubber.

The rubber layer (B) of claim (2) is a layer containing an organic rubber that can be vulcanized with an organic peroxide and an organic peroxide.

The organic rubber and the organic peroxide are used in the rubber layer (
It is the same as the organic rubber and organic peroxide contained in A).

The structure of the invention of claim (2) other than the above is the same as that of the invention of claim (1).

e. Examples Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Examples 1-14; Comparative Examples 1-6 These embodiments correspond to the invention of claim (1).

A crosslinking agent and an organopolysiloxane were added to an unvulcanized rubber containing silicone rubber as a main component on a roll mill at 40° C. according to the formulation shown in Table 1.

On the other hand, a crosslinking agent was added using a roll mill to an organic rubber that had been kneaded using a Banbury mixer according to the formulation shown in Table 2.

The silicone rubber and organic rubber thus prepared were each made into an unvulcanized sheet with a thickness of about 211 IIl, brought into contact with each other, and press-molded into a 4M vulcanized sheet. The vulcanization was performed at 170°C for 10 minutes.

The obtained vulcanized sheet was punched out to IC11 width and JIS
A T-peel test was conducted according to K6854.

The results are shown in Table-3.

Japan Synthetic Rubber - Silicone Rubber 2,5-dimethyl-2,5-5 (t-
Butylperoxy)hexane 50χ degree of polymerization = 4,
As is clear from the results shown in Table 3, examples in which at least one of the silicone rubber and the organic rubber contains an organopolysiloxane In Nos. 1 to 14, the adhesion between the layer containing silicone rubber and the layer containing organic rubber is extremely good.

On the other hand, the silicone rubber and organic rubber used in Comparative Examples 1 to 6 do not contain organopolysiloxane, and a layer containing silicone rubber and a layer containing organic rubber do not contain organopolysiloxane. Poor adhesion to other layers.

Examples 15-24; Comparative Examples 7-14 These embodiments correspond to the invention of claim (2).

Silicone rubber composite materials (A) to (E) were prepared using the following raw materials and according to the following formulation.

Silicone rubber composite material (A); Sen (1) Polydiorganosiloxane: degree of polymerization 5,000, vinyl group content 0.1 mol%, remaining organic group - methyl group, terminal group - trimethylsilyl group (2) E P n M (3) Fine powder silica: (4) Softener: (5) Anti-aging agent (6) Vulcanizing agent: (7) Zinc white: (8) Stearic acid: Mooney viscosity (ML+ 4a, r..℃) ) = 47, propylene unit content 43% by weight, iodine number -6, average particle size 16-μ, specific surface area 240 po/9-, wet silica specific gravity 0.87? , pour point -15°C, aniline point 144°C, viscosity at 98°C 30 cSt paraffinic oil Manufactured by Ciba Geigi Co., Ltd., Irganoχ 010 α, α'-bis (L-butyl baroxy) p-diisopropylbenzene rubber No. 1 Grade used in ordinary organic rubber Polydiorganosiloxane PDM (parts by weight) 5 5 Fine powder silica Softener Zinc white stearic acid Antioxidant Vulcanizing agent A 1.71 Banbury mixer is used as a kneader. death,
Kneading was carried out at a rotor rotation speed of 60 rpm and a starting temperature of 70°C. The kneading temperature in the first stage is approximately 100°C
1 The kneading temperature in the second stage is about 130°C.

The vulcanizing agent was added in a 10 inch roll. 170°C1
After press vulcanization for 10 minutes, secondary vulcanization was performed at 150°C for 2 hours.

Silicone rubber composite materials (B) to (D); ARIOI) lυ Irimethylhate ■ Genshi ■ Xane 005 Crosslinking aid (triallyl isocyanurate) -55 Vulcanization conditions: 170°C x 20 minutes Press vulcanization only The above silicone In the rubber composition (a), 0.1 mol% of organic groups bonded to silicon atoms are vinyl groups, the remainder is methyl groups, the value of a in the above average composition formula is 2,000, and the average Linear polymethylvinylsiloxa 71 with a degree of polymerization of 6,000
00 parts by weight and 35 parts by weight of finely powdered silica, the surface of which has been made hydrophobic by treatment with organopolysiloxane, is blended in a kneader until it becomes uniform.

The polymethylhydrodienesiloxane (0) has a terminal end capped with a trimethylsilyl group and is a linear chain consisting of 20 methylhydrodienesiloxane units.

Acrylic rubber or fluororubber, silicone rubber composition (a), and polymethylhydrodiene siloxane (El) were added in sequence to the rubber mixer (60~
(Heated to 80°C, set at 60 rpm) and kneaded, and when it became homogeneous, an isopropanol solution containing 1% by weight of chloroplatinic acid was added and further kneaded, and it became homogeneous again. After that, it was discharged. The temperature of the rubber composition at the time of discharge was 150 to 200°C.

Silicone rubber composite material (E); with respect to the above composite material (B), the degree of polymerization is 4 and the vinyl group weight is 5.
5 parts by weight of 0 mol % cyclic organopolysiloxane were added.

A crosslinking agent was added using a roll mill to an organic rubber that was kneaded using a Banbury mixer according to the formulation shown in Table 1 above.

Using the silicone rubber composite material and organic rubber thus obtained, rubber laminates as shown in Table 4 were prepared and tested for adhesive strength.

Adhesive strength was evaluated by the following method.

l) Sheet test The silicone rubber composite was made into a sheet of about 2ms+ and the organic rubber compound was made into a sheet of about 4 times, which were brought into contact with each other and press-molded into a vulcanized sheet with a thickness of 6mm. In addition, when the organic rubber to be adhered to the silicone rubber composite material was a diene rubber, a sheet of about 2+ma was used, and a saturated rubber layer was further brought into contact with the outside to prepare a vulcanized sheet. Vulcanization at 170″C 2
It took 0 minutes. Punch out the vulcanized sheet to lai width and JI
A T-peel test was performed according to SK6854. The peeling speed was 50 mm/min.

2) Hose test A silicone rubber composite material and an organic rubber compound were prepared using a two-layer extruder, with an inner diameter of 15 m+a and an inner layer of approximately 0.5 f.
The silicone rubber composite of III was co-extruded with approximately two organic rubber formulations in the outer layer. If diene rubber is used for the outer layer, III
1 of the saturated rubber layer was extruded. The head temperature of the extruder was 60"C. After molding, the hose was heated to a steam pressure of 7 kgf.
/cm for 20 minutes.

The hose was cut to a width of 5ffIII, the interface between the inner layer and the outer layer was cut out with a knife, and separated by hand to test whether peeling occurred at the interface.

3) Aging test The samples prepared in sections 1) and 2) were left in a gear oven at 150° C. for 24 hours, and then the tests in sections 1) and 2) were conducted.

The results are shown in Table-4.

As is clear from the results shown in Table 4, all the systems with organopolysiloxane added have excellent adhesive strength even after heat aging, but the systems without additives have poor adhesive strength both before and after heat aging. There is.

f0 Effects of the Invention By the method of the present invention, a rubber laminate in which a rubber layer containing silicone rubber as a main component or a silicone rubber composite layer and a layer containing organic rubber are firmly vulcanized and bonded can be obtained.

Specific uses of the rubber laminate manufactured by the present invention include, for example, two-layer and three-layer rubber hoses for transporting water conveyance, automobiles, air, suction, high pressure, oxygen/acetylene, oil resistance, etc. Rubber belts such as conveyor belts and power transmission belts for automobiles, railway vehicles, industrial machinery, aircraft, electrical and
Anti-vibration rubber for electronic equipment, ships and ports, steel manufacturing, paper manufacturing, printing, spinning and dyeing, office equipment, electroacoustic products, agricultural machinery, rubber rolls for plastic manufacturing, blankets, chemical industry, water treatment equipment, air pollution prevention, etc. , rubber lining gasket materials, roofing, and flooring in the food industry, etc.
Rubber plates for materials, sealing materials for general housing, architecture, civil engineering, vehicles, automobiles, aircraft, ships, etc., molded rubber products such as seals, oil seals, diaphragms, pulp, buffer rubber, etc. for gas, water, etc. Rubber pipes and tubes for medical use, weather strips for automobiles, draining rubber, door window frames,
Applications include extruded rubber products such as trunk seals, wiper rubber openings, and wire covering materials, as well as athletic equipment, rubberized fabric products, flexible containers, rubber gloves, and sponge rubber products.

In addition, the laminated structure is two or three layers (including reinforcing fibers).
The body can be considered.

Claims (2)

[Claims] (1) Unvulcanized rubber layer containing silicone rubber (A
) and an unvulcanized rubber layer (B) containing an organic rubber are stacked and vulcanized, the rubber laminate having the following average unit formula in at least one of the above (A) or (B) layers. (I
1. A rubber laminate, characterized in that 0.1 to 20 parts by weight of organopolysiloxane (C) having a degree of polymerization of 3 to 500 shown in ) is blended with respect to 100 parts by weight of rubber. R_aSiO_(_4_-_a_)_/_2…………(
I) [wherein R is a substituted or unsubstituted monovalent hydrocarbon group,
5 to 50 mol% of R is a vinyl group, and a is 0<a
The number is <4. ] (2) The unvulcanized rubber layer (A) is a layer containing a mixture of silicone rubber and organic rubber that can be vulcanized with an organic peroxide and an organic peroxide, and the unvulcanized rubber layer ( Claim (1), characterized in that B) is a layer containing an organic rubber and an organic peroxide different from the organic rubber contained in the layer (A) which is vulcanizable with an organic peroxide. rubber laminate.