JPH0689158B2 - Method for manufacturing laminated rubber molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for producing a laminated rubber molded article, particularly a laminated rubber having an improved adhesive force at the interface in a rubber molded article obtained by laminating two kinds of rubbers having different compositions. The present invention relates to a method for manufacturing a molded body.

[Prior Art] A rubber molded body is usually produced by vulcanizing a single rubber by die pressing or extrusion molding, and this molded product is widely used in various industrial fields.

In addition, recently, due to the improvement of the compounding technology of materials, the number of molded products made by laminating different kinds of rubber materials has increased. For this, for example, rubber contact made by laminating conductive rubber and insulating rubber, and oil resistant rubber An automobile hose and the like in which a heat resistant rubber is laminated are known.

[Problems to be Solved by the Invention] However, in the case of a laminated rubber molded product obtained by laminating different kinds of rubber, the product yield is remarkably reduced because a part of the interface or the edge part has already peeled off at the initial stage of production. This is also disadvantageous, and there is a drawback that the molded product undergoes interfacial peeling due to weak adhesion between different rubbers when used for a long period of time, and this solution is required.

[Means for Solving the Problems] The present invention relates to a method for producing a laminated rubber molded product that solves the above disadvantages and drawbacks, and it is 1) a) that the average composition formula is (Where R is an unsubstituted or substituted monovalent hydrocarbon group, a =
1.95 to 2.05) 100 parts by weight of organopolysiloxane, b) 5 to 500 parts by weight of finely divided silica-based filler, c)
Organopolysiloxane composition consisting of 0.1 to 5 parts by weight of organic peroxide and / or 2) a) 100 parts by weight of ethylene-propylene organic polymer and / or ethylene-propylene-diene organic polymer, b) organopolysiloxane 1 to 100 parts by weight, c) 10 to 150 parts by weight of finely divided silica-based filler, and d) 0.1 to 5 parts by weight of organic peroxide in a polyolefin-based organic polymer composition having a specific surface area of at least 50 m ² / g. Some of the above silica fine powder 1),
2) Add 1 to 10 parts by weight to 100 parts by weight of the component at a temperature of 80
The organopolysiloxane composition and the polyolefin-based organic polymer composition are molded and vulcanized as a laminated structure after addition and mixing at a temperature of not higher than 0 ° C.

That is, as a result of various studies on the method for producing a laminated rubber molded product in which the adhesive force at the interface between different rubbers has been improved, the present inventors have found that the different rubber composition constituting the laminated rubber molded product is an organopolysiloxane composition. Ethylene-propylene organic polymer and / or ethylene-propylene-
In the case of a polyolefin-based organic polymer composition containing a diene-based organic polymer and an organopolysiloxane as a main material, silica fine powder having a specific surface area of at least 50 m ² / g is added to either or both of these compositions. Then, it was found that the adhesive strength of this interface is significantly improved, the organopolysiloxane composition, the type of polyolefin-based organic polymer composition, the type of silica having a specific surface area of at least 50 m ² / g added thereto, The present invention was completed by conducting research on the amount and the like.

This will be described in more detail below.

[Operation] The laminated rubber molded article of the present invention has an organopolysiloxane composition and / or a polyolefin-based organic polymer composition having the above-described composition and a specific surface area of at least 50.
Silica fine powder of m ² / g is added, and the two compositions are laminated and vulcanized.

The organopolysiloxane as the component (a) constituting the organopolysiloxane composition as the first component has the formula And R is a methyl group, an ethyl group, a propyl group,
Alkyl group such as butyl group, vinyl group, allyl group, alkenyl group such as butaniel group, phenyl group, aryl group such as tolyl group or part or all of hydrogen atoms bonded to carbon atoms of these groups are halogen atoms, Chloromethyl group substituted with cyano group, chloropropyl group, 3,3,
The same or different unsubstituted or substituted monovalent hydrocarbon group selected from 3-trifluoropropyl group, 2-cyanoethyl group and the like, and a is a positive number of 1.90 to 2.05. It is preferable that this compound has a linear molecular structure, but there is no problem even if it contains a partially branched molecular structure. Further, this may have a molecular chain terminal blocked with a toluorganosilyl group or a hydroxyl group. Examples of the triorganosilyl group include a trimethylsilyl group, a dimethylvinylsilyl group, a methylphenylvinylsilyl group and a methyldiphenylsilyl group. Examples thereof include a group, a methyldivinylsilyl group and a trivinylsilyl group. The degree of polymerization of this resin is not particularly limited, and the viscosity at 25 ° C. may be 300 cS or more.

Further, in the organopolysiloxane composition, b)
The finely divided silica filler as a component is added for the purpose of reinforcing, thickening, improving processability and increasing the amount of silicone rubber. This includes fumed silica, wet silica, and fumes whose surface is hydrophobized. Examples of the silica include wet silica, fine silica powder, diatomaceous earth, and the like, and it is preferable that these have a specific surface area of 1 m ² / g or more. The blending amount of this product is 100 parts of the above-mentioned organopolysiloxane.
If the amount is less than 5 parts by weight, the desired reinforcing property cannot be obtained and the processability becomes insufficient. If added in excess of 500 parts by weight, processing characteristics such as mold flowability and dischargeability of the composition are improved. Since it is extremely lowered, it is required to be in the range of 5 to 500 parts by weight, and the preferable range is 10 to 300 parts by weight.

Next, in this organopolysiloxane composition, c)
The organic peroxide as a component is used as a curing agent for accelerating the heat curing of this composition, and includes benzoyl peroxide, monochlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t- Butyl perbenzoate, dicumyl peroxide, 2,5
-Bis- (t-butylperoxy) -2,5-dimethylhexane, 2,5-bis- (t-butylperoxy) -2,5-
Dimethylhexyne and the like are exemplified, but the blending amount may be 0.1 to 5 parts by weight with respect to 100 parts by weight of the organopolysiloxane as the component (a).

The organopolysiloxane composition as the first component can be obtained by uniformly mixing the predetermined amounts of the above-mentioned components (a) to (c), which is a Banbury mixer, a pressure kneader, two rolls, etc. It may be carried out by kneading using a usual rubber compounding device such as that described above.However, when the kneading of the rubber composition is carried out under heating, the composition of the curing agent is decomposed by the decomposition of the curing agent. It is necessary to lower the temperature to below the temperature.

The first component has a degree of polymerization of 100 or less, a low-molecular weight siloxane, a silanol group-containing silane, a dispersant such as an alkoxy group-containing silane, and a heat resistance improver such as iron oxide, cerium oxide, iron octylate, and titanium oxide. It is optional to add a pigment for coloring, a flame retardant aid such as a platinum compound or a palladium compound, and other additives such as a foaming agent added to a usual silicone rubber composition.

Next, the organic polymer as the component a) constituting the polyolefin-based organic polymer composition as the second component is an ethylene-propylene-based organic polymer (hereinafter abbreviated as EPM) or an ethylene-propylene-diene-based organic polymer (hereinafter, EPDM) or a mixture thereof, and known EPM or EPDM can be used, but these have an ethylene content of 40 to 70% by weight.
The EPDM is preferably one using ethylidene norbornene, dicyclopentadiene, or 1,4-hexanediene as a diene monomer.

The organopolysiloxane as the component b) mixed with the component a) is added in order to improve the heat resistance, weather resistance and processability of the polyolefin composition as the second component. May be the same as the organopolysiloxane as the above-mentioned first component (a) component, but if this amount is less than 1 part by weight relative to 100 parts by weight of the above-mentioned organic polymer as the (a) component. The effect becomes insufficient, and if the amount exceeds 100 parts by weight, the rubber molded product obtained from this composition will have weak strength.
A range of 100 parts by weight is required, but a preferred range is 5 to 70 parts by weight.

Next, the finely divided silica filler as the component c) which constitutes the second component is used as a reinforcing agent, and this may be the same as the component b) of the first component described above. If the amount is less than 10 parts by weight based on 100 parts by weight of the organic polymer as the component a), a sufficient reinforcing effect cannot be obtained, and if it exceeds 150 parts by weight, the physical properties of the rubber molded product obtained from this composition are improved. However, the preferred range is 30 to 80 parts by weight. The silica fine powder may be kneaded with a wetting agent composed of various silanes and low molecular weight siloxanes, if necessary.

The organic peroxide as the component d) in the second component is a vulcanizing agent for accelerating the heat curing of the polyolefin-based composition as the second component. -T-butyl peroxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxide) Oxy) hexine,
1,1-bis-t-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 1,1-bis- (t-butylperoxy) Oxy) 3,3,5-trimethylcyclohexane and the like are exemplified, but the blending amount may be 0.1 to 5 parts by weight with respect to 100 parts by weight of the organic polymer as the component a).

The polyolefin-based organic polymer composition as the second component contains a predetermined amount of the above-mentioned components a) to d) in the same manner as in the production of the first component using a Banbury mixer, a pressure kneader,
It can be obtained by uniformly mixing with two rolls, etc., but it is optional to add known additives such as an antioxidant, a vulcanization accelerator, a mold stain preventing agent, and a foaming agent. To be done.

The production of a laminated rubber molded article according to the present invention is made by laminating a molded article made from the above-mentioned organopolysiloxane composition as the first component and the polyolefin-based organic polymer composition as the second component. In this case, the first component and the second component may be separately molded and then laminated, or may be those that are laminated simultaneously with molding by extrusion molding or the like.

However, in the method of the present invention, in order to improve the adhesive force at the interface between the different types of rubber molded products, the first component and / or
Or the second component has a specific surface area of at least 50 before its molding.
It is required to add fine silica powder that is m ² / g. The addition of silica fine powder having a specific surface area of at least 50 m ² / g is 1 to 100 parts by weight of the total weight of the first and second components in order to improve the adhesive strength at the interface between different rubber molded products. If the amount is less than 10 parts by weight, the improvement of the adhesive force at the interface becomes insufficient, and even if the amount is more than 10 parts by weight, further improvement of the adhesive force at the interface cannot be achieved.
This may be added to both the first and second components,
Although it may be added only to either the first component or the second component, post-addition to only the second component is preferable in view of the roll processability of the composition and the physical properties of the resulting laminated molded product. It

Further, the addition of the silica fine powder having a specific surface area of at least 50 m ² / g to the first component and / or the second component may be carried out at the same time as the above-mentioned compounding for producing the first component and the second component. If it is added at a temperature of ℃ or more, it will not be possible to improve the adhesive strength at the interface of different rubber laminates. Therefore, add the first and second components at a temperature of 80 ℃ or less after preparation. Is required.

The rubber composition added with silica fine powder having a specific surface area of at least 50 m ² / g thus obtained is then laminated and molded, which is compression molding using a mold, extrusion molding, calendering. A pipe, a sheet, a shaped article, a hose in which an organopolysiloxane composition as a first component and a polyolefin-based organic polymer composition as a second component have an adhesive interface by a known rubber molding method such as molding, transfer molding, and injection molding. , Molded into a desired shape such as a gasket,
Vulcanize. Incidentally, this crosslinking-curing may be carried out by a method used for curing a usual rubber, and therefore, the vulcanization temperature is 100 to 500 ° C. which is higher than the decomposition temperature of the organic peroxide contained in the composition. The time may be 5 seconds to 10 minutes, but if necessary, 150 to 250 ° C for 30 minutes to 24 minutes.
Vulcanization after time is optional.

The laminated rubber molding thus obtained has a high adhesive strength at the adhesive interface and is less likely to cause a peeling phenomenon, so that the occurrence of defective products is reduced and the commercial value is improved.

[Examples] Next, examples of the present invention and comparative examples will be given. Parts in the examples are parts by weight.

Examples 1 to 3, Comparative Example 1 (CH ₃ ) ₂ SiO unit 99.825 mol%, (CH ₃ ) (CH ₂ = CH) SiO unit 0.1
5 parts by mole of (CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 unit 0.025 mole% with an average degree of polymerization of 8,000 rubbery dimethylpolydiloxane 100 parts, diphenylsilanediol as a dispersant 3 parts, Molecular chain terminal silanol group dimethylpolysiloxane (polymerization degree n = 10) 4 parts and fumed silica-Aerosil 200 [product name of Nippon Aerosil Co., Ltd.] 40 parts were added, and the mixture was kneaded with two rolls and then 140 ° C. And heat-treated for 4 hours to prepare a base compound I.

In addition, ethylene-propylene-diene-based organic polymer
In 70 parts of Esplen 567 [trade name of Sumitomo Chemical Co., Ltd.], 99.5 mol% of (CH ₃ ) ₂ SiO unit and (CH ₃ ) (CH ₂ = CH) SiO unit
30 parts of 0.5 mol% methylvinylpolysiloxane raw rubber with an average degree of polymerization of 8,000, 30 parts of precipitating silica Nibseal LP [trade name of Nippon Silica Co., Ltd.] with a specific surface area of 230 m ² / g, zinc flower 5 Parts and 1 part of stearic acid were added and kneaded with a pressure kneader to prepare a base compound II.

Next, this compound I and / or II silica fine powder with a specific surface area of 200 m ² / g Aerosil 200 (mentioned above)
Then, dicumyl peroxide as a vulcanizing agent was added in the amount shown in Table 1, and after uniformly kneading, the compounds I and II were 150 mm wide, 150 mm long and 2 m thick using an extruder.
Make a sheet piece of m and stick these two sheets together, 1
Press-cure for 10 minutes under the condition of 60 ℃ × 100 kg / cm ² , cut the obtained laminated sheet to a width of 20 mm to make a test piece, and peel this test piece in the 180 ° direction at a peeling speed of 50 mm / min. The adhesive strength was measured and the results shown in Table 1 were obtained. These were 1.3 to 2.1 kgf / cm.
The values of the above values indicate that the rubber broke at the time of peeling, but for comparison, those without adding Aerosil 200 to Compounds I and II had weak adhesive strength of 0.65 kgf / cm. Did.

Example 4, Comparative Examples 2-3 Using the base compounds I and II obtained in Examples 1 to 3, 2,5-dimethyl-2,5-bis (t-butylper) as a vulcanizing agent was used. (Oxy) hexane or 2,5-dimethyl-2,5-dibenzoylperoxyhexane was added in the amount shown in Table 2, and Aerosil 200 was added to the base compound II in the amount shown in Table 2. Was treated in the same manner as in Examples 1 to 3 to prepare a test pace, and its adhesive strength was examined. The results as shown in Table 2 were obtained. However, for comparison, Aerosil 200 was added at all. If not, when the addition amount of Aerosil 200 was 12 parts, the results are shown in Table 2.

Examples 5-6, Comparative Examples 4-5 Base compounds I and II obtained in Examples 1-3
Dicumyl peroxide as a vulcanizing agent is added to these in an amount shown in Table 3, and this base compound II has a specific surface area of 300 m ² / g and is a fine powder silica Aerosil 300 [Japan Product name manufactured by Aerosil Co., Ltd.]
Was added at room temperature or 50 ° C., a test piece was prepared in the same manner as in Examples 1 to 3, and the adhesive strength thereof was measured. The results shown in Table 3 were obtained.

However, for comparison, the addition of this Aerosil 300 at 100 ° C
When the addition of Aerosil 300 was carried out at the time of blending the base compound II (Comparative Example 5), the laminated rubber molded article was as shown in Table 3 in both cases. The adhesive strength was low, and they caused interfacial peeling.

Example 7 The base compounds I and II obtained in Examples 1 to 3 were used, in which the amounts of the vulcanizing agent and Aerosil 20 shown in Table 4 were used.
Add azobisisobutyronitrile or azodicarbonamide as a foaming agent with
30 kg at room temperature after forming a foam sheet by normal pressure hot air vulcanization
When a laminated sheet was prepared by pressing at a pressure of / cm ² , and the adhesive strength of this was investigated, the results as shown in Table 4 were obtained.

[Effects of the Invention] The present invention relates to a method for producing a laminated rubber molded article, which comprises an organopolysiloxane composition and / or a polyolefin organic polymer composition having a specific surface area of at least 50 m ² / g as described above. After mixing a certain silica fine powder, the organopolysiloxane composition and the polyolefin-based organic polymer compound are molded and vulcanized as a laminated structure. According to this, the laminated rubber molded body is obtained. The adhesive strength at the interface between the different types of rubbers constituting the composition is remarkably improved, and since these are not separated at the interface, the occurrence of defective products is reduced and the commercial value is improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Hatakeyama 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) Reference JP-A-61-209242 (JP, A)

Claims (1)

[Claims] 1. The average composition formula is (Where R is an unsubstituted or substituted monovalent hydrocarbon group, a =
1.95 to 2.05) 100 parts by weight of organopolysiloxane, b) 5 to 500 parts by weight of finely divided silica-based filler, and c) 0.1 to 5 parts by weight of organic peroxide, and / or 2 ) A) ethylene-propylene-based organic polymer and /
Or ethylene-propylene-diene organic polymer 10
0 parts by weight, b) 1 to 100 parts by weight of organopolysiloxane, c) 10 to 150 parts by weight of finely divided silica-based filler, d) 0.1 to 5 parts by weight of organic peroxide, in a polyolefin organic polymer composition, This organopolysiloxane composition is prepared by adding and mixing 1 to 10 parts by weight per 100 parts by weight of the above components 1) and 2) of silica fine powder having a specific surface area of at least 50 m ² / g at a temperature of 80 ° C. or less. And a polyolefin-based organic polymer composition as a laminated structure, which is vulcanized and vulcanized.