JP3407639B2 - 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 (Japanese Patent Application No. 9-200839). 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.
A novolac type phenol resin , a resole type phenol resin and a bisphenol A type epoxy resin are applied to one or both sides of a metal plate surface-treated with a complex type chromate treatment agent.
Hydrogenated nitrile rubber 100 through the adhesive containing fat
Achieved by a rubber laminated metal sheet laminated with a vulcanized layer of hydrogenated nitrile rubber containing at least 20 to 150 parts by weight of at least one of silicic acid, calcium silicate and calcium carbonate per part by weight. can also further (silicate, containing one at least of the calcium silicate and calcium carbonate) adding a hydrogenated nitrile rubber compound to.

[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.

On a metal plate having one or both surfaces subjected to composite chromate treatment, an adhesive containing novolac type phenol resin and resol type phenol resin as main components is used as alcohol, ketone or a mixed solvent thereof, preferably methyl ethyl ketone solution. Coated, one side thickness about 1-1
An adhesive layer of 0 μm, preferably about 2-5 μm is formed.

The novolac type phenolic resin contains phenols and formaldehyde in a molar ratio of about 0.1 to 1.0 .
It was obtained by reacting in the presence of an acidic catalyst such as hydrochloric acid or oxalic acid, and as phenols,
For example, phenol, m-cresol, a mixture of m-cresol and p-cresol, bisphenol A and the like are used. In the present invention, those which are solid at room temperature having a melting point of about 60 to 170 ° C., preferably about 100 to 150 ° C. and soluble in organic solvents such as alcohols and ketones are used.

The resol type phenolic resin contains phenol and formaldehyde in a molar ratio of about 1 to 3,
It can be obtained by reacting in the presence of a basic catalyst such as an alkali metal or magnesium hydroxide. At that time, as the phenols, for example, phenol, a mixture of m-cresol and p-cresol, p-tertiary butylphenol, p-phenylphenol, o-position to the phenolic hydroxyl group such as bisphenol A, p-position or Any one can be used as long as it has two or three substitutable nuclear hydrogen atoms at the o, p-positions.

In the adhesive, as a curing agent for these phenolic resins, about 0.5 to 5 relative to their total amount is used.
Hexamethylenetetramine is added and used in a weight% ratio. If the amount added is less than this, the heat resistance of the adhesive layer will decrease, while if it is added in a ratio greater than this, there is a tendency for the amount of gas generated to increase during heat curing of the rubber.

A bisphenol A type epoxy resin is further added to the adhesive for use. Bisphenol
For A type epoxy resin, epoxy equivalent is about 180-2700
It has a liquid or softening point of about 15 at room temperature (25 ° C).
Solids at 0 ° C. or lower are used in a proportion of about 30 to 200 parts by weight, preferably about 50 to 150 parts by weight, based on 100 parts by weight of the total amount of phenol resin. The higher the proportion of the bisphenol A type epoxy resin used, the higher the heat resistance, but the antifreeze resistance tends to decrease.

The reaction between the bisphenol A type epoxy resin and the phenolic resin , even in the absence of a catalyst,
It progresses by heating to about 100 ° C or higher, but generally 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzylimidazole. , 1-benzyl-2-methylimidazole, 2,4-diamino-6- [2-methylimidazoline- (1)]-ethyl s-triazine and other imidazole compounds as curing catalysts against bisphenol A type epoxy resin It is used in a proportion of about 4% by weight or less, and if it is used in a proportion of more than this, the stability of the adhesive with time will decrease.

The total amount of the Le resin and an epoxy resin - [0015] in the adhesive, the more hydrogenated nitrile rubber compound phenolate
It can be added in an amount of about 40 parts by weight or less, preferably about 10 to 30 parts by weight, per 100 parts by weight. Addition of the hydrogenated nitrile rubber compound further improves the adhesiveness between the rubber layer and the adhesive layer, but if it is used in a ratio higher than this, peeling occurs by immersion in a high humidity antifreeze. The hydrogenated nitrile rubber is a hydride of a copolymer rubber of about 30 to 50 mol% acrylonitrile and about 70 to 50 mol% butadiene, and the unsaturated bond amount is 20% or less,
Preferably, 10% or less is used, which can be crosslinked with a commonly used organic peroxide, and at the time of crosslinking, polyallyl such as triallyl isocyanurate, triallyl cyanurate, and trimethylolpropane trimethacrylate is used. It is preferable to use a functional unsaturated compound together as a crosslinking aid.

Incorporation of an inorganic filler into the hydrogenated nitrile rubber compound is effective in preventing the adhesive layer from peeling off when immersed in a high temperature antifreeze solution. As the inorganic filler, it is effective to add at least one of silicic acid, calcium silicate and calcium carbonate in addition to carbon black. As for 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 air oxidation of vaporized SiO, thermal decomposition of sodium silicate Wet method white carbon etc. produced by a method such as a specific surface area (by nitrogen adsorption method) of about 20 to 200 m ² / g, preferably about 30 to 100 m ² / g
What is used. As calcium silicate, one having a specific surface area of about 20 to 150 m ² / g and a weakly alkaline pH is used. In addition, calcium carbonate has a specific surface area of about
5 to 100 m ² / g, average particle size of about 10 μm or less, and weakly alkaline pH are 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 used in a proportion of about 20 to 150 parts by weight, preferably about 40 to 100 parts by weight, per 100 parts by weight of hydrogenated nitrile rubber. If the blending ratio is less than this, it is difficult to prevent foaming or peeling of the blister in the liquid contact part and the vapor part when the antifreeze is soaked in half. On the other hand, if it is used at a ratio higher than this, the antifreeze resistance is satisfied, but the heat aging resistance is significantly reduced.

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 butyl peroxy) valerate, etc., about 1 to 10 parts by weight per 100 parts by weight of hydrogenated nitrile rubber,
It is preferably used in a proportion of about 2 to 8 parts by weight.

The adhesive comprising the above components is prepared as a solution dissolved in an organic solvent such as a ketone-based or alcohol-based solvent at a concentration of about 2 to 10% by weight, and is prepared on one side or both sides of the metal plate. It is applied to a dry thickness of about 1 to 10 μm and air-dried under room temperature conditions, and preferably about 1 to 10 μm.
Heat treatment is performed at 100 to 200 ° C. for about 5 to 30 minutes to form an adhesive layer there.

On the adhesive layer thus formed, about 5% of unvulcanized hydrogenated nitrile rubber compound is added.
~ 1000 μm, preferably about 10 ~ 120 μm so as to form a single-sided vulcanizate layer, a method of applying as an organic solvent solution of hydrogenated nitrile rubber compound (about 500 μm
(When the thickness is less than m) or the method of putting the rubber sheet out with a calendar roll (when the thickness is about 500 μm or more).

The vulcanization of the hydrogenated nitrile rubber compound is generally about 150 to 230 ° C., about 20 to 100 Kgf / cm ² , about 0.5 to 3
It is carried out by pressure vulcanization for 0 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.

[0022]

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.

[0023]

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 type 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 〃 Hydrogenated nitrile rubber compound 13.5 〃 Methyl ethyl ketone 950 〃 (hydrogenated nitrile rubber compound) Hydrogenated nitrile rubber (Zeon Pole 2000L, Nippon Zeon product) 100 parts by weight SRF carbon black 60 〃 Calcium carbonate 40 〃 Silica 20 〃 Calcium silicate 20 〃 Aging Inhibitor (Ouchi Emerging Chemicals Nocrac CD) 1.5 〃 〃 (Ouchi Emerging Chemicals Nocrac MBZ) 1.5 〃 Triallyl isocyanurate 2 〃 1,3-bis (tertiary butylperoxy) isopropylbenzene 4 〃

On this adhesive layer, a rubber solution prepared from 25 parts by weight of the hydrogenated nitrile rubber compound, 7.5 parts by weight of methyl ethyl ketone and 67.5 parts by weight of toluene.
(Solid concentration 25% by weight) is applied and dried at 60 ° C. for 15 minutes to form an unvulcanized rubber layer having a thickness of 20 μm on one side, then 180
Pressure vulcanization was carried out at 60 ° C. and 60 Kgf / cm ² for 10 minutes. afterwards,
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 form a sticking prevention layer with a thickness of 5 μm. Let

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 the hydrogenated nitrile rubber compound of Example 1,
80 parts by weight of SRF carbon black and 20 parts of calcium carbonate without using silica and calcium silicate.
Changed to parts by weight.

Example 3 In the hydrogenated nitrile rubber compound of Example 1,
SR without calcium carbonate and calcium silicate
The amount of F carbon black was changed to 80 parts by weight .

Example 4 In the hydrogenated nitrile rubber compound of Example 1,
The amount of SRF carbon black was changed to 80 parts by weight without using calcium carbonate and silica.

[0031]

Comparative Example 1 In the hydrogenated nitrile rubber compound of Example 1,
Without using silica and calcium silicate, SRF carbon black amount to 80 parts by weight and calcium carbonate amount to 5 parts.
Changed to parts by weight.

Comparative Example 2 In the hydrogenated nitrile rubber compound of Example 1,
SR without calcium carbonate and calcium silicate
The amount of F carbon black was changed to 80 parts by weight, and the amount of silica was changed to 5 parts by weight.

Comparative Example 3 In the hydrogenated nitrile rubber compound of Example 1,
80 parts by weight of SRF carbon black and 5 parts of calcium silicate without using calcium carbonate and silica.
Changed to parts by weight.

Comparative Example 4 In the hydrogenated nitrile rubber compound of Example 1, S
The amount of RF carbon black was changed to 5 parts by weight, and the amounts of calcium carbonate and calcium silicate were changed to 70 parts by weight.

Comparative Example 5 In Example 1, instead of the hydrogenated nitrile rubber compound, the same amount of the nitrile rubber compound having the following composition was used to prepare the adhesive and the rubber solution. (Nitrile rubber compound) Nitrile rubber (Japanese synthetic rubber product N235S) 100 parts by weight SRF carbon black 80 〃 calcium carbonate 40 〃 silica 20 〃 calcium silicate 40 〃 zinc oxide 5 〃 anti-aging agent (non-flex RD) 2 〃 Triallyl isocyanurate 2 〃 1,3-bis (tertiary butylperoxy) isopropylbenzene 2.5 〃

Comparative Example 6 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 in each of the above Examples and Comparative Examples are shown in the following table. Table Example Comparative Example Measurement items 1 2 3 4 1 2 3 4 5 6 [Air heating aging test] Peeling in bending test None None None None None None None Large Large Large [Antifreeze liquid immersion test] Peeling at gas-liquid interface Yes No No No No No No No No No peeling in large liquid immersion unit just slightly slightly large large large No Nashi been

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

Claims (3)

(57) [Claims] 1. A novolac type phenol resin , a resole type phenol resin and a bisphenol are provided on one or both sides of a metal plate surface-treated with a complex type chromate treatment agent.
Vulcanization of hydrogenated nitrile rubber containing about 20 to 150 parts by weight of at least one of silicic acid, calcium silicate and calcium carbonate per 100 parts by weight of hydrogenated nitrile rubber via an adhesive containing an A-type epoxy resin. A rubber laminated metal plate formed by laminating product layers. 2. The rubber laminated metal plate according to claim 1, wherein an adhesive containing hydrogenated nitrile rubber compound is further used. 3. The rubber laminated metal plate according to claim 1, wherein an adhesive to which a hydrogenated nitrile rubber compound containing at least one of silicic acid, calcium silicate and calcium carbonate is further added is used.