JP2012125960A - Vulcanized rubber laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vulcanized rubber laminate having sufficient adhesion by adhering an unvulcanized epichlorohydrin rubber composition layer with an unvulcanized fluororubber composition layer through vapor vulcanization.SOLUTION: The vulcanized rubber laminate is manufactured by heating, vulcanizing and adhering (A) an unvulcanized epichlorohydrin rubber composition layer and (B) an unvulcanized fluororubber composition layer. In the laminate, (A) the unvulcanized epichlorohydrin rubber composition layer contains the followings (a) to (e): (a) epichlorohydrin rubber, (b) at least one kind of a thiourea compound selected from ethylenethiourea, tributyl thiourea, dibutyl thiourea, dilauryl thiourea, N,N'-diphenyl thiourea, trimethyl thiourea and N,N'-diethylthiourea (c) a 1,8-diazabicyclo(5,4,0)undecene-7 salt, (d) a quinoxaline type vulcanizing agent and (e) an acid acceptor.

Description

  The present invention relates to a vulcanized rubber laminate in which fluororubber and epichlorohydrin rubber are firmly bonded.

  In recent years, exhaust gas regulations from automobiles have become very strict, and gasoline transpiration regulations, one of them, have been increasingly strengthened mainly in the United States. In response to such severe demands, fuel hose for automobiles has also been developed with a combination of heat aging resistance, weather resistance, acid resistance gasoline resistance, alcohol resistance gasoline resistance, gasoline impermeability, etc. . One of the fuel hose materials is fluorine rubber. However, since it is expensive and has a problem in cold resistance, a laminate using a thin layer of fluororubber for the inner layer and epichlorohydrin rubber for the outer layer is often used.

  However, in the case of a laminated hose made of the above different rubber composition, the adhesiveness between the hoses becomes the most important. In the case of a fluororubber layer and an epichlorohydrin-based rubber layer, it is generally known that the adhesiveness is poor. Therefore, means such as blending certain additives with epichlorohydrin-based rubber are usually used (Patent Documents). 1-4). However, in actual hose production, steam vulcanization is often performed, and the expected adhesiveness cannot be exhibited by steam vulcanization, and improvement thereof is demanded.

JP-A 64-11180 JP-A-9-85898 JP-A-2-160867 JP 2006-306053 A

  The present invention relates to a vulcanized rubber laminate having sufficient adhesion by heating vulcanization / adhesion, particularly steam vulcanization / adhesion, of an unvulcanized epichlorohydrin rubber composition layer and an unvulcanized fluororubber composition layer. The purpose is to provide.

The present invention relates to a laminate in which (A) an unvulcanized epichlorohydrin rubber composition layer and (B) an unvulcanized fluororubber composition layer are heat vulcanized and bonded, and the unvulcanized epichlorohydrin rubber composition. The physical layer is a laminate containing the following (a) to (e).
(A) epichlorohydrin rubber (b) at least one thiourea compound selected from ethylene thiourea, tributyl thiourea, dibutyl thiourea, dilauryl thiourea, N, N′-diphenylthiourea, trimethylthiourea and N, N′-diethylthiourea ( c) 1,8-diazabicyclo (5,4,0) undecene-7 salt (d) quinoxaline vulcanizing agent (e) acid acceptor

  The present invention is preferably a laminate in which (A) an unvulcanized epichlorohydrin rubber composition layer and (B) an unvulcanized fluororubber composition layer are steam vulcanized and bonded.

  In the present invention, the (b) thiourea compound is preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the (a) epichlorohydrin rubber.

  In the present invention, the (c) 1,8-diazabicyclo (5,4,0) undecene-7 salt (hereinafter abbreviated as DBU salt) is 0.2% relative to 100 parts by weight of the (a) epichlorohydrin rubber. It is preferable that it is -3 weight part, and said (c) DBU salt has preferable DBU-phenol resin salt.

  In the present invention, the (d) quinoxaline vulcanizing agent is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the (a) epichlorohydrin rubber, and the (d) quinoxaline vulcanizing agent. The agent is preferably 6-methylquinoxaline-2,3-dithiocarbonate.

  In the present invention, the synthetic hydrotalcite wherein (e) the acid acceptor is preferably a metal compound and / or an inorganic microporous crystal, the metal oxide is magnesium oxide, and is a kind of inorganic microporous crystal. Is more preferable.

  In the present invention, the fluororubber used in the (B) unvulcanized fluororubber composition layer is vinylidene fluoride-hexafluoropropene binary copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropene ternary copolymer. It is preferable that it is a coalescence.

  The vulcanized rubber laminate obtained by the present invention is very excellent in adhesion between both vulcanized rubbers particularly during steam vulcanization, and has a strong adhesion surface. Therefore, one side is exposed to required environments such as anti-septic gasoline resistance, gasoline permeation resistance, and alcohol-containing gasoline resistance, and the other side is required for heat aging resistance, weather resistance, gasoline resistance, etc. It is extremely effective for applications exposed to the environment, such as fuel hoses and filler hoses.

  The (A) unvulcanized epichlorohydrin rubber composition in the present invention comprises at least (a) an epichlorohydrin rubber, (b) a thiourea compound, (c) a DBU salt, (d) a quinoxaline vulcanizing agent, and (e) an acid acceptor. Contains agents.

The (a) epichlorohydrin rubber in the (A) unvulcanized epichlorohydrin rubber composition is an epichlorohydrin-alkylene oxide copolymer such as an epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-propylene oxide copolymer or the like. Examples of the polymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer, epichlorohydrin-ethylene oxide-propylene oxide-allyl glycidyl ether quaternary copolymer of epichlorohydrin-alkylene oxide-allyl glycidyl ether, etc. it can. Preferred are epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer, and more preferred epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether. A terpolymer. The molecular weight of these homopolymers or copolymers is not particularly limited, but is usually about ML _{1 + 4} (100 ° C.) = 30 to 150 in terms of Mooney viscosity.

  In the case of epichlorohydrin-ethylene oxide copolymer, the copolymerization ratio thereof is epichlorohydrin 5 mol to 95 mol%, preferably 10 mol% to 75 mol%, more preferably 10 to 65 mol%, ethylene oxide 5 mol% to 95 mol%, preferably 25 mol%. It is -90 mol%, More preferably, it is 35 mol%-90 mol%.

  In the case of an epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer, the copolymerization ratio thereof is, for example, epichlorohydrin 4 mol to 94 mol%, preferably 9 mol% to 74 mol%, more preferably 9 to 64 mol%, ethylene oxide 5 mol%. It is -95 mol%, Preferably it is 25 mol%-90 mol%, More preferably, it is 35 mol%-90 mol%, Allyl glycidyl ether 1 mol%-10 mol%, Preferably it is 1 mol%-7 mol%, More preferably, it is 1 mol%-6 mol%.

  Examples of the (b) thiourea compound in the (A) unvulcanized epichlorohydrin rubber composition of the present invention include ethylenethiourea, tributylthiourea, dibutylthiourea, dilaurylthiourea, N, N′-diphenylthiourea, trimethylthiourea, N , N′-diethylthiourea is preferable, and trimethylthiourea is particularly preferable. These thiourea-based vulcanization accelerators are preferable in terms of excellent adhesiveness as compared with thiourea-based anti-aging agents such as 1,3-bis (dimethylaminoethyl) thiourea.

  The blending amount of the (b) thiourea compound is 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.1 to 3 parts by weight based on 100 parts by weight of the (a) epichlorohydrin rubber. Parts by weight. Within these ranges, adhesive strength with fluororubber is sufficiently obtained, and the mechanical properties of the vulcanizate are not impaired, which is preferable.

  As the (c) DBU salt in the (A) unvulcanized epichlorohydrin rubber composition of the present invention, DBU-carbonate, DBU-stearate, DBU-2-ethylhexylate, DBU-benzoate, DBU-salicylate, DBU-3-hydroxy-2-naphthoate, DBU-phenol resin salt, DBU-2-mercaptobenzothiazole salt, DBU-2-mercaptobenzimidazole salt and the like can be mentioned, preferably DBU- A phenol resin salt is mentioned.

  The compounding amount of the (c) DBU salt is 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight with respect to 100 parts by weight of the (a) epichlorohydrin rubber. Within these ranges, a sufficient adhesive force with the fluororubber can be obtained, and an appropriate vulcanization rate can be obtained, so that it is preferable without causing any processing difficulties.

  Examples of the (d) quinoxaline vulcanizing agent in the (A) unvulcanized epichlorohydrin rubber composition of the present invention include 2,3-dimercaptoquinoxaline, quinoxaline-2,3-dithiocarbonate, 6-methylquinoxaline- 2,3-dithiocarbonate, 5,8-dimethylquinoxaline-2,3-dithiocarbonate and the like can be mentioned, and 6-methylquinoxaline-2,3-dithiocarbonate is preferable.

  The amount of the (d) quinoxaline vulcanizing agent is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the (a) epichlorohydrin rubber. More preferably, it is 1-3 weight part. Within these ranges, it is preferable because the physical properties normally expected as an epichlorohydrin rubber vulcanizate can be obtained without sufficiently crosslinking and the vulcanizate becoming too rigid.

  Examples of the (e) acid acceptor in the (A) unvulcanized epichlorohydrin rubber composition of the present invention include metal compounds and / or inorganic microporous crystals. Such metal compounds include Group IIA metal oxides, hydroxides, carbonates, carboxylates, silicates, borates, phosphites, Periodic Table Group IVA metals. Oxides, basic carbonates, basic carboxylates, basic phosphites, basic sulfites, tribasic sulfates and the like.

  Specific examples of the metal compound as the (e) acid acceptor include magnesium oxide, magnesium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, sodium carbonate, quicklime, slaked lime, calcium carbonate, calcium silicate, stear Calcium phosphate, zinc stearate, calcium phthalate, calcium phosphite, zinc white, tin oxide, lisage, red lead, lead white, dibasic lead phthalate, dibasic lead carbonate, basic lead silicate, tin stearate, Examples thereof include basic lead phosphite, basic tin phosphite, basic lead sulfite, and tribasic lead sulfate. Particularly preferred acid acceptors include magnesium oxide, calcium carbonate, slaked lime, quicklime and sodium carbonate.

  The inorganic microporous crystal refers to a crystalline porous body, and can be clearly distinguished from an amorphous porous body such as silica gel and alumina. Examples of such inorganic microporous crystals include zeolites, aluminophosphate type molecular sieves, layered silicates, synthetic hydrotalcites, alkali metal titanates and the like. A particularly preferred acid acceptor is synthetic hydrotalcite.

  The zeolites are natural zeolite, A-type, X-type, Y-type synthetic zeolite, sodalite, natural or synthetic mordenite, various zeolites such as ZSM-5, and metal substitutes thereof. It may be used in combination of two or more. Further, the metal of the metal substitution product is often sodium. As the zeolite, those having a large acid-accepting ability are preferable, and A-type zeolite is preferable.

The synthetic hydrotalcite has the following general formula (1)
_{Mg X Zn Y Al Z (OH} ) (2 (X + Y) + 3Z-2) CO 3 · wH 2 O (1)
[Wherein, x and y are each a real number of 0 to 10 having a relation of x + y = 1 to 10, z is a real number of 1 to 5, and w is a real number of 0 to 10, respectively]. As an example of the hydrotalcite represented by the general formula (1),
_{Mg 4.5 Al 2 (OH) 13} CO 3 · 3.5H 2 O
Mg _4.5 Al ₂ (OH) ₁₃ CO _{3
Mg 4 Al 2 (OH) 12} CO 3 · 3.5H 2 O
Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O
Mg ₅ Al ₂ (OH) ₁₄ CO ₃ .4H ₂ O
_{Mg 3 Al 2 (OH) 10} CO 3 · 1.7H 2 O
Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ .3.5H ₂ O
Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃
Etc.

  As said (e) acid acceptor in this invention, a magnesium oxide and / or a synthetic hydrotalcite are more preferable from a viewpoint of storage stability.

  The amount of the (e) acid acceptor is preferably 0.2 to 50 parts by weight, more preferably 0.5 to 50 parts by weight, particularly 1 to 20 parts per 100 parts by weight of the (a) epichlorohydrin rubber. Parts by weight. Within this range, it is preferable because the physical properties normally expected as an epichlorohydrin rubber vulcanizate can be obtained without sufficiently crosslinking and the vulcanizate becoming too rigid.

  In the present invention, a known retarder usually used together with these vulcanizing agents can be used.

  Examples of the retarder used in the present invention include N-cyclohexylthiophthalimide, phthalic anhydride, an organic zinc compound, acidic silica, and the like. The compounding amount thereof is (a) 100 parts by weight of epichlorohydrin rubber. 0 to 10 parts by weight is preferable, and 0.1 to 5 parts by weight is more preferable.

  Further, the (A) unvulcanized epichlorohydrin rubber composition used in the present invention includes various compounding agents usually used in the technical field in addition to the above-mentioned acid acceptor, such as anti-aging agents and fillers. Further, reinforcing agents, plasticizers, processing aids, pigments, flame retardants, lubricants, and the like can be arbitrarily blended.

  As the fluororubber in the (B) unvulcanized fluororubber composition, a highly fluorinated elastic copolymer is preferable. For example, a copolymer of vinylidene fluoride and other copolymerizable fluoroolefin is used. Can be mentioned. Examples of the fluorinated olefin include hexafluoropropene, pentafluoropropene, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, etc. Two or more kinds are used as copolymerization components.

  Examples of preferred fluororubbers include fluororubbers of vinylidene fluoride-hexafluoropropene binary copolymer and vinylidene fluoride-tetrafluoroethylene-hexafluoropropene terpolymer.

  A known compounding agent such as a vulcanizing agent, a vulcanization accelerator, a stabilizer, a colorant, a plasticizer, and a reinforcing agent is added to the (B) unvulcanized fluororubber composition depending on the purpose. .

  Examples of the method for producing a laminate in the present invention include a method of laminating both rubber compositions by simultaneous extrusion molding and sequential extrusion molding, and then steam heating vulcanization or steam heating vulcanization molding. Further, it is possible to employ a method in which one rubber composition is weakly heated and vulcanized to such an extent that it is not deformed, and then both are laminated and sufficiently steam-heated and vulcanized and molded. As a method other than the steam heating vulcanization of the laminate laminated by the extrusion molding, a known method such as mold heating, air bath, infrared ray, microwave, lead vulcanization and the like can be arbitrarily adopted. In vulcanization, the heating temperature is usually 100 to 200 ° C., and the heating time varies depending on the temperature, but a range of 0.5 to 300 minutes is selected.

  As an aspect when the laminate of the present invention is applied to a fuel oil-based hose, a two-layer hose in which fluorine rubber is arranged on the inner layer of the hose and epichlorohydrin rubber is arranged on the outer layer, and three layers in which a braided reinforcing layer is arranged on the outer side A typical example is a hose or a hose having a four-layer structure in which a rubber layer is further provided on the outside thereof. As the braiding material used for the three-layer hose or the four-layer hose, braided materials such as polyester fiber, polyamide fiber, glass fiber, vinylon fiber, and cotton are usually used. Further, as the outermost layer material used for the above four-layer hose, in addition to epichlorohydrin-based rubber, ethylene-acrylate rubber, chloroprene rubber, chlorinated polyethylene rubber, chlorosulfonated polyethylene, etc., heat aging resistance, weather resistance, oil resistance, etc. Synthetic rubber with is usually used.

  In the following, typical examples will be given as examples, but the present invention is not limited thereto.

Examples 1-6, Comparative Example 1
The epichlorohydrin rubber composition shown in Table 1 was kneaded with a kneader and an open roll to obtain a sheet (i) having a thickness of 2 to 2.5 mm. On the other hand, the fluororubber composition shown in Table 2 was kneaded in the same manner as described above to prepare a sheet (ii) having a thickness of 1 to 1.5 mm.

(Press vulcanized laminate)
As shown in Tables 3 and 4, the sheet (i) and the sheet (ii) were bonded to each other, and the thickness obtained by pressing at 160 ° C. and 20 to 25 kg / cm ² for 30 minutes using a 3 mm-thick spacer. A sheet having a thickness of 3.0 to 3.5 mm is used as a vulcanized rubber laminate.

(Steam vulcanized laminate)
As shown in Tables 3 and 4, the above sheet (i) and sheet (ii) were bonded together, held at 80 ° C. under no pressure for 4 minutes, and then pressurized at 82 kg / cm ² for 4 minutes until room temperature. A steam vulcanized laminate is obtained by steam vulcanizing an unvulcanized laminate obtained by cooling at 160 ° C. for 30 minutes.

(Adhesion evaluation)
The press vulcanized and steam vulcanized laminates were cut into strips of 1.0 × 10 cm to produce test specimens for adhesion test, and a T peel test was conducted at 25 ° C. and a tensile speed of 50 mm / min. About 1-3 and the comparative example 1, peeling strength (kN / m) was measured and the peeling state of Examples 1-6 and the comparative example 1 was observed visually. The evaluation criteria are shown below. Tables 3 and 4 show the test results of the press vulcanized laminate and the steam vulcanized laminate, respectively.
◯: Adhered firmly, causing interlayer rubber breakdown.
X: Not adhered at all, and peeling at the interface occurs.

The compounding agents used in Examples and Comparative Examples are shown below.
* 1 “Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer (molar ratio 48: 48: 4)” manufactured by Daiso Corporation.
* 2 “DHT-4A” manufactured by Kyowa Chemical Industry Co., Ltd.
* 3 “P-152” manufactured by Daiso Corporation
* 4 Daisonet XL-21S manufactured by Daiso Corporation
* 5 DuPont vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer "Viton B-50"

As shown in Table 3, in the adhesion by press vulcanization, the adhesion surface between both vulcanized rubbers is strong even in Comparative Example 1 which does not contain (b) a thiourea compound in the unvulcanized epichlorohydrin rubber composition. Met. However, in the adhesion by steam vulcanization, Comparative Example 1 which does not contain (b) a thiourea compound in the unvulcanized epichlorohydrin rubber composition did not adhere.
On the other hand, as shown in Tables 3 and 4, Examples 1 to 6, which are vulcanized rubber laminates of the present invention, are not only bonded by press vulcanization but also bonded by steam vulcanization. The adhesion between them is very excellent, no peeling occurs on the bonding surface, and the bonding surface is strong.

  The vulcanized rubber laminate of the present invention is configured as described above, and the laminate is very excellent in adhesion between both vulcanized rubbers and has a strong adhesive surface. Therefore, one side is exposed to required environments such as anti-septic gasoline resistance, gasoline permeation resistance, and alcohol-containing gasoline resistance, and the other side is required for aging resistance, weather resistance, gasoline resistance, etc. It is extremely effective for applications exposed to the environment, such as fuel hoses and filler hoses.

Claims (10)

(A) An unvulcanized epichlorohydrin rubber composition layer and (B) a laminate obtained by heat vulcanizing and bonding an unvulcanized fluororubber composition layer, the (A) unvulcanized epichlorohydrin rubber composition The laminated body in which a layer contains the following (a)-(e).
(a) Epichlorohydrin rubber
(b) at least one thiourea compound selected from ethylenethiourea, tributylthiourea, dibutylthiourea, dilaurylthiourea, N, N′-diphenylthiourea, trimethylthiourea and N, N′-diethylthiourea
(c) 1,8-diazabicyclo (5,4,0) undecene-7 salt
(d) Quinoxaline vulcanizing agent
(e) Acid acceptor   The laminate according to claim 1, which is a laminate comprising (A) an unvulcanized epichlorohydrin rubber composition layer and (B) an unvulcanized fluororubber composition layer which are vapor vulcanized and bonded.   The laminate according to claim 1 or 2, wherein the (b) thiourea compound is 0.1 to 5 parts by weight with respect to 100 parts by weight of the (a) epichlorohydrin rubber.   The (c) 1,8-diazabicyclo (5,4,0) undecene-7 salt is 0.2 to 3 parts by weight based on 100 parts by weight of the (a) epichlorohydrin rubber. Laminated body.   (c) The 1,8-diazabicyclo (5,4,0) undecene-7 salt is a 1,8-diazabicyclo (5,4,0) undecene-7-phenol resin salt. Laminated body.   The laminate according to any one of claims 1 to 5, wherein the (d) quinoxaline vulcanizing agent is 0.5 to 5 parts by weight with respect to 100 parts by weight of the (a) epichlorohydrin rubber.   (D) The laminate according to any one of claims 1 to 6, wherein the quinoxaline vulcanizing agent is 6-methylquinoxaline-2,3-dithiocarbonate.   (E) Acid acceptor is a metal compound and / or inorganic microporous crystal, The laminated body of Claims 1-7 characterized by the above-mentioned.   (E) The acid acceptor is magnesium oxide and / or synthetic hydrotalcite, The laminate according to any one of claims 1 to 8. A laminated hose using the laminate according to claim 1.