JP3407638B2 - Rubber laminated metal plate - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber laminated metal plate. More specifically, it relates to a rubber laminated metal plate having excellent heat resistance and antifreeze resistance.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 53-55342 discloses an undercoating agent for a hot water-resistant adhesive can containing a bisphenol A type epoxy resin and a resol type phenol resin. This primer is strong and durable for adhesion between can bodies, but adhesion between metal and nitrile rubber or hydrogenated nitrile rubber is insufficient, so that the rubber layer-adhesive layer Peeling occurs.

Further, in the applicant's invention described in JP-A-6-335990, NB is provided on one side or both sides of a metal plate.
R, on the other hand, a primer layer and NBR formed from a phenol resin-based primer containing 20% by weight or more of a white filler, carbon black, zinc oxide, organic peroxide, and 20% by weight or more of this The rubber laminated metal plate in which the vulcanized rubber layers formed from the rubber compound containing the white filler, carbon black, zinc oxide, and organic peroxide are sequentially laminated, has excellent antifreeze resistance and is effectively used as a gasket. It is said that it will be done.

More specifically, a gasket material obtained from such a rubber laminated metal plate has improved rubber strength and adhesive strength with a primer, and even under severe impact and friction conditions, cracks occur in that portion. It does not cause blistering or the like, and is particularly good at preventing peeling of the engine gasket contacting part with cooling water due to antifreeze, but it may only peel off at the adhesive layer due to heat of the engine and severe impact.

[0005]

The present applicant has previously found that the adhesive layer has excellent heat resistance and antifreeze resistance, and does not cause peeling of the adhesive layer even by long-term air heating or immersion in a high temperature antifreeze solution (hydrogenation). Nitrile rubber laminated metal plate, nitrile rubber or hydrogenated nitrile through an adhesive containing bisphenol A type epoxy resin and resol type phenolic resin on one or both sides of the metal plate surface-treated with composite type chromate treatment agent. A rubber laminated metal plate in which a vulcanized rubber layer is laminated has been proposed ( JP-A-11-77890).
News ). It has been found that the laminated metal sheet proposed here sufficiently satisfies the long-term air heating aging test at 150 ° C., for example, but is not necessarily satisfactory in terms of heat resistance at higher temperatures required these days.

An object of the present invention is to provide a rubber laminated metal plate which satisfies the long-term air heating aging test at a high temperature of 175 ° C. and is excellent in antifreeze resistance.

[0007]

The object of the present invention is as follows.
On one or both sides of the metal plate surface-treated with the composite type chromate treatment agent, via an adhesive containing a bisphenol A type epoxy resin and a resol type phenol resin ,
Achieved by a rubber laminated metal plate laminated with a vulcanizate layer of nitrile rubber or hydrogenated nitrile rubber containing a liquid plasticizer having a viscosity (25 ° C) of 500 to 5000 cps. containing resin and the liquid plasticizer can also be added either or both of (hydrogenated) nitrile rubber compound.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a metal plate, a stainless steel plate whose surface is roughened by shot blasting, scotch bride, hairline, dull finishing, SPCC steel plate, aluminum plate, etc. are generally alkali-degreased and then silica, It is used after being treated with a complex type chromate treatment agent (about 20 to 100 mg / m ² ) containing a phosphoric acid compound and chromic acid and subjected to a chemical conversion treatment to form an anticorrosive film. In the case of stainless steel sheets, conventionally, the adhesion has been improved by simply roughening the surface of the sheet by methods such as shot blasting and scotch bride.However, it is largely peeled off due to long-term air heating aging and immersion in high temperature antifreeze solution. When the film is further formed, such peeling is not observed. In the case of SPCC plate, zinc phosphate coating and iron phosphate coating are also formed. A metal plate having a thickness of about 0.2 to 0.8 mm is used for the gasket material.

The bisphenol A type epoxy resin has an epoxy equivalent of about 180 to 2700 and has room temperature conditions.
A liquid having a liquid or softening point of about 150 ° C. or lower at (25 ° C.) is used.

The resol type phenol resin is obtained by reacting phenols and formaldehyde in a molar ratio of about 1 to 3 in the presence of a basic catalyst (alkali metal, magnesium hydroxide, etc.). Examples of phenols include phenol, m-cresol and p-
Mixtures with cresol, those having 2 or 3 substitutable nuclear hydrogen atoms at the o- and / or p-positions relative to the phenolic hydroxyl group such as p-tertiary butylphenol, p-phenylphenol, bisphenol A, etc. If so, any can be used.

The reaction between the two proceeds even if the catalyst is absent in the presence of heating at about 100 ° C. or higher, but generally 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-un Decyl imidazole, 2-heptadecyl imidazole, 2-phenyl imidazole, 1-benzyl imidazole, 1-benzyl-2-methyl imidazole, 2,4-diamino-6- [2-methyl imidazoline- (1)]-ethyl s- Imidazole compound such as triazine, as a curing catalyst, about 4 wt% to bisphenol A type epoxy resin
It is used in a proportion of not more than%, and if it is used in a proportion of more than this, the stability of the adhesive with time will decrease. Also, hexamethylenetetramine or the like can be added and used as a curing agent for the phenol resin. The addition ratio is 5% by weight or less with respect to the resol-type phenol resin, and if it is used at a ratio higher than this, the amount of gas generated during heat curing increases.

A novolac type phenol resin may be added to the adhesive and used. The novolac type phenol resin is obtained by reacting phenols and formaldehyde in the presence of an acidic catalyst (hydrochloric acid, oxalic acid, etc.) at a molar ratio of about 0.6 to 1.0. m-Cresol, a mixture of m-cresol and p-cresol, bisphenol A and the like are used.

The mixture of the bisphenol A type epoxy resin and the resol type phenolic resin or the novolac type phenolic resin has a weight ratio of the epoxy resin to the phenolic resin (mixture) of about 0.3 to 2, preferably about 0.5 to 1.5. Used. As the proportion of the epoxy resin used increases, the heat resistance improves, but the antifreeze resistance tends to decrease.

In the adhesive, a nitrile rubber compound or a hydrogenated nitrile rubber compound further containing a liquid plasticizer is added in an amount of about 40 parts by weight or less, preferably about 10 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin. ~ 30
It can be used by mixing in a ratio of parts by weight. (Hydrogenation)
The compounding of the nitrile rubber compound improves the adhesiveness between the rubber layer and the adhesive layer, but if it is used at a ratio higher than this, peeling occurs when it is immersed in the high temperature antifreeze.

The liquid plasticizer is an adipic acid-based, trimellitic acid-based, epoxy-based or phosphoric acid-based polyester or polyether having a viscosity (25 ° C.) of about 500 to 50,000.
A liquid material of cps, preferably about 2000 to 10000 cps is used. When a material having a viscosity lower than this is used, the rubber layer is slightly peeled off in the air heating aging test and the antifreeze liquid immersion test (gas-liquid interface). On the other hand, if a material having a viscosity higher than this is used, peeling will occur in the rubber layer in the bending test after the air pressure aging test.

These liquid plasticizers are used in an amount of about 2 to 50 parts by weight, preferably about 5 to 20 parts by weight, per 100 parts by weight of (hydrogenated) nitrile rubber.
Used in proportions by weight. If the amount of the liquid plasticizer is less than this, the rubber layer will be cracked, cracked, peeled or the like due to vibration, impact, bending or the like after heat deterioration of the rubber.

The adhesive comprising the above components is prepared as a solution dissolved in a ketone-based or alcohol-based organic solvent to a concentration of about 2 to 10% by weight and applied to one or both sides of the metal plate. After being applied to a dry thickness of about 1 to 10 μm and air-dried under room temperature conditions, it is preferably further heat-treated at about 100 to 200 ° C. for about 5 to 30 minutes, and the adhesive layer is then applied. To form.

On the adhesive layer thus formed, an unvulcanized nitrile rubber compound or hydrogenated nitrile rubber compound containing the liquid plasticizer as described above is applied in a thickness of about 5 to 120 μm. It is applied as an organic solvent solution of a rubber compound so as to form a one-sided vulcanizate layer. Examples of these rubber compounds are:
Those used in the examples described later are used.

Incorporation of an inorganic filler into the rubber compound is effective in preventing the adhesive layer from peeling off when immersed in a high temperature antifreeze solution. As the inorganic filler, in addition to carbon black,
It is effective to add at least one of silicic acid, calcium silicate and calcium carbonate. As silicic acid, dry method white carbon produced by thermal decomposition method of halogenated silicic acid or organic silicon compound or method of heating and reducing silica sand and oxidizing air vaporized SiO, thermal decomposition of sodium silicate Wet method white carbon etc. manufactured by the method, etc., with a specific surface area (by nitrogen adsorption method) of about 20 ~
200m ² / g, preferably it is used of about 30 to 100 m ² / g. Calcium silicate has a specific surface area of about 20-150m
² / g, weakly alkaline one is used. Further, as calcium carbonate, one having a specific surface area of about 5 to 100 m ² / g, an average particle diameter of about 10 μm or less, and a weakly alkaline pH is used. Any of these may be a commercially available product that is generally marketed for the rubber industry. In addition, these can be used after treating the particle surface with a fatty acid salt, a rosin salt or an epoxy resin.

At least one of silicic acid, calcium silicate and calcium carbonate is (hydrogenated) nitrile rubber 100
It is used in a proportion of about 20 to 150 parts by weight, preferably about 40 to 100 parts by weight, per part by weight. Below this proportion, antifreeze
It becomes difficult to prevent the occurrence of foaming or peeling of the blister in the liquid contact part and the vapor part during the submerged immersion.

As the vulcanizing agent, sulfur or the like can be used, but an organic peroxide is generally used. Examples of the organic peroxide include ditertiary butyl peroxide,
Dicumyl peroxide, tertiary butylcumyl peroxide, 1,1-di (tertiary butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (tertiary butylperoxide) (Oxy) hexane, 2,5-dimethyl-2,5-di (tertiary butylperoxy) hexyne-3,1,3-di (tertiary butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5 -Di (benzoylperoxy) hexane, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, n
-Butyl-4,4'-di (tertiary butylperoxy) valerate is used in a proportion of about 1 to 10 parts by weight, preferably about 2 to 8 parts by weight, per 100 parts by weight of (hydrogenated) nitrile rubber. .

Vulcanization of rubber compounds is generally about 150
It is carried out by pressure vulcanization at about 230 ° C., about 20 to 100 Kgf / cm ² for about 0.5 to 30 minutes. Then, for the purpose of preventing adhesion of the surface of the vulcanized rubber, graphite, carbon black, paraffin wax, etc. are the main components, and a binder such as cellulose, acrylic resin, polybutadiene resin, etc. is added thereto and dispersed in a solvent such as toluene. The dispersion liquid is applied to form a non-adhesive layer having a thickness of about 2 to 10 μm, thereby preventing seizure and adhesion.

[0023]

EFFECTS OF THE INVENTION The rubber laminated metal sheet according to the present invention shows no peeling in the rubber layer during long-term air heating aging or immersion in a high temperature antifreeze solution, and even after being exposed to a high temperature of 175 ° C. No deterioration is observed in the rubber layer, so that the rubber layer does not crack, break, or peel off due to vibration, impact, bending, or the like. Further, even when used as a gasket around an engine, there is an effect that peeling due to thermal deterioration of the bead apex is not seen.

[0024]

EXAMPLES The present invention will now be described with reference to examples.

Example 1 Surface dull-finished SUS301 steel plate (thickness: 0.2 mm) was degreased with alkali, and then a composite chromate treatment agent containing silica, a phosphoric acid compound and chromic acid was applied at an application amount of 50 mg / m ^2. Then, an adhesive having the following composition was formed on both surfaces of the formed anticorrosion coating so as to have a thickness of about 2 μm on one surface. Bisphenol A type epoxy resin 25.0 parts by weight (epoxy equivalent 400, melting point 70 ° C) Cresol modified novolac type phenol resin 17.5 〃 Resol type phenol resin (MW380) 7.5 〃 2-Ethyl-4-methylimidazole 0.34 〃 Hexamethylenetetramine 2 〃 Nitrile rubber compound 13.5 〃 Methyl ethyl ketone 950 〃 (Nitrile rubber compound) Nitrile rubber (Nippon Synthetic Rubber Product N235S) 100 parts by weight SRF carbon black 80 〃 Calcium carbonate 40 〃 Silica 20 〃 Calcium silicate 40 〃 Zinc oxide 5 〃 Antiaging agent ( Seiko Chemical Products Non-flex RD) 2〃 Triallyl isocyanurate 2〃 1,3-bis (tertiary butylperoxy) isopropylbenzene 2.5〃 Adipic acid polyester plasticizer 5〃 (viscosity 2700cps, molecular weight about 2000)

A rubber solution (solids concentration 25% by weight) prepared from 25 parts by weight of the above-mentioned nitrile rubber compound, 7.5 parts by weight of methyl ethyl ketone and 67.5 parts by weight of toluene was applied onto this adhesive layer, and the mixture was applied at 60 ° C. for 15 minutes. After drying to form an unvulcanized rubber layer with a thickness of 20 μm on one side, 180 ° C, 60 Kgf /
Pressure vulcanization was carried out at 10 cm ² for 10 minutes. After that, for the purpose of preventing sticking of the vulcanized rubber surface, a toluene dispersion of polyethylene wax added with a polybutadiene resin binder was applied to it, and heat-treated at 200 ° C for 3 minutes to obtain a thickness.
A 5 μm anti-stick layer was formed.

The rubber laminated metal plate thus obtained was tested for the following items.

Air heating aging test: A rubber laminated metal plate is placed in a gas oven and heated in air according to the heating conditions (175 ° C., 500 hours) specified in JIS K-6257 vulcanized rubber aging test method. Then, as an evaluation of adhesiveness, JIS
An antifreeze liquid immersion test in which a flex resistance test (using a 6 cm diameter mandrel) was performed according to K-5400, and the presence or absence of peeling was visually determined: Antifreeze liquid of a rubber laminated metal plate (non-amine long life coolant; Toyota genuine LLC) ) Half dipping in 50% by volume water dilution, 150 ° C in a pressure vessel, vapor-liquid interface after 500 hours (vapor part) and liquid phase immersion part (wetted part)
The presence or absence of peeling was visually determined.

Example 2 In Example 1, the same amount of hydrogenated nitrile rubber compound was used instead of the nitrile rubber compound used in the adhesive and rubber solution. The hydrogenated nitrile rubber compound used was composed of the following components. Hydrogenated nitrile rubber (Zeonpol 2000L, Nippon Zeon product) 100 parts by weight SRF carbon black 60 〃 Calcium carbonate 40 〃 Silica 20 〃 Calcium silicate 20 〃 Anti-aging agent (Ouchi Shinko Chemicals Nocrac CD) 1.5 〃 (Ouchi Emerging chemical products Nocrac MBZ) 1.5〃 triallyl isocyanurate 2〃 1,3-bis (tertiary butylperoxy) isopropylbenzene 4〃 adipic acid polyester plasticizer 5〃 (viscosity 2700cps, molecular weight about 2000)

Comparative Example 1 In Example 1, a nitrile rubber compound containing no adipic acid type polyester plasticizer was used.

Comparative Example 2 In Example 2, a hydrogenated nitrile rubber compound containing no adipic acid polyester plasticizer was used.

Comparative Example 3 In Example 2, as the adipic acid type polyester plasticizer compounded in the hydrogenated nitrile rubber compound,
The same amount with a viscosity of 20 cps and a molecular weight of about 430 was used.

Comparative Example 4 In Example 1, a surface dull-finished SUS301 steel sheet which was not surface-treated with the composite type chromate treatment agent was used.

The measurement results of each of the above examples and comparative examples are shown in the following table. Table Examples Comparative Examples Measurement items 1 2 1 2 3 4 [Air heating aging test] Slight peeling in bending test Large Large Small Large [Antifreeze liquid immersion test] Peeling at gas-liquid interface None None None None Slightly large liquid No peeling at the immersion part No No No No No No Yes

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (5)

(57) [Claims] 1. A viscosity (25 ° C.) of 500 to 500 is applied to one or both sides of a metal plate surface-treated with a composite type chromate treatment agent via an adhesive containing a bisphenol A type epoxy resin and a resol type phenol resin. A rubber laminated metal plate obtained by laminating a vulcanized product layer of nitrile rubber or hydrogenated nitrile rubber containing a liquid plasticizer of 5000 cps . 2. The rubber laminated metal plate according to claim 1, wherein an adhesive containing a novolac type phenol resin is further used. 3. The rubber laminate according to claim 1 or 2, wherein a nitrile rubber compound containing a liquid plasticizer having a viscosity (25 ° C.) of 500 to 5000 cps or an adhesive to which a hydrogenated nitrile rubber compound is added is used. Metal plate. 4. A nitrile rubber compound or a hydrogenated nitrile rubber compound containing a liquid plasticizer,
The rubber laminated metal sheet according to claim 3, further comprising at least one of silicic acid, calcium silicate and calcium carbonate. 5. The rubber according to claim 1, wherein at least one of silicic acid, calcium silicate and calcium carbonate is added to the vulcanizate layer of nitrile rubber or hydrogenated nitrile rubber containing a liquid plasticizer. Laminated metal plates.