JP3407651B2 - 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 after long-term air heating or immersion in a high temperature antifreeze solution (hydrogenation). As a nitrile rubber laminated metal plate, nitrile rubber or hydrogenation 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 liquid resol type phenol resin. A rubber laminated metal plate in which a vulcanized product layer of nitrile rubber 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.
Achieved by a rubber laminated metal plate in which a vulcanized product layer of nitrile rubber containing fluororubber is laminated via an adhesive containing fat, and a nitrile rubber compound containing fluororubber is further added to this adhesive. You can also do it.

[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 simply by roughening the surface of the steel sheet by methods such as shot blasting and scotch bride.However, it is largely peeled off due to long-term air heating aging and high temperature antifreeze immersion, and therefore the composite chromate layer. 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. For gasket material applications, the thickness is approximately
A metal plate of about 0.2 to 0.8 mm is used.

On a perforated metal plate having one surface or both surfaces treated with a composite chromate, an adhesive containing novolac type phenol resin and resol type phenol resin as main components is alcohol, ketone or a mixed solvent thereof, preferably a methyl ethyl ketone solution. And the like to form an adhesive layer having a thickness on one side of about 1 to 10 μm, preferably about 2 to 5 μm.

The novolac type phenol resin is obtained by reacting phenols and formaldehyde in a molar ratio of about 0.1 to 1.0 in the presence of an acidic catalyst such as hydrochloric acid or oxalic acid. For example, phenol, m-cresol, a mixture of m-cresol and p-cresol, bisphenol A and the like are used.
In the present invention, the melting point is about 60 to 170 ° C., preferably about 1
Alcohol, which is solid at room temperature of 00-150 ℃,
Those soluble in organic solvents such as 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 present invention, those which are liquid at room temperature (molecular weight of about 200 to 1000) and soluble in organic solvents such as alcohols and ketones are preferably used.

Regarding the novolac type phenol resin and the resol type phenol resin, the former is about 40 to 90% by weight, preferably about 50 to 80% by weight, and the latter is about 60 to 10% by weight, preferably about 50 to about 50% by weight. Used in a proportion of 20% by weight. If the ratio of the former is less than this, the initial adhesive strength with rubber decreases,
On the other hand, if it is used at a ratio higher than this, peeling will occur in the adhesive layer when immersed in hot water or high temperature antifreeze.

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.

In this adhesive, a bisphenol A type epoxy resin is further added and used. 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 addition of the bisphenol A type epoxy resin has a preferable effect in terms of heat resistance of the adhesive.

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.

A nitrile rubber compound containing a fluororubber may be added to the adhesive and used. As the fluororubber, a combination of vinylidene fluoride and at least one of hexafluoropropene, pentafluoropropene, trifluoroethylene, tetrafluoroethylene, vinyl fluoride, perfluoro (methyl vinyl ether), perfluoro (propyl vinyl ether), etc. Polymers, preferably vinylidene fluoride-hexafluoropropene copolymer and vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer are used. These fluororubbers have a number average molecular weight Mn of about 1 to 100.
About 10,000 are preferable, and as the vinylidene fluoride-hexafluoroethylene copolymer, a liquid having Mn of about 10,000 or less, preferably about 3000 or less is also used.
In practice, commercially available products such as those manufactured by DuPont Viton series are used as they are.

The fluororubber is used in a proportion of about 2 to 20 parts by weight, preferably about 5 to 15 parts by weight, per 100 parts by weight of nitrile rubber. If the amount of fluororubber is less than this, the rubber layer may crack due to vibration, impact, bending, etc. after heat deterioration of the rubber.
If it is used in a larger amount than this, it is impossible to prevent the rubber layer from swelling or peeling at the liquid contact portion and the vapor phase portion when the antifreeze is half-immersed.

As the nitrile rubber forming the main component of the nitrile rubber compound containing such an amount of fluororubber, a copolymer rubber of about 30 to 50 mol% acrylonitrile and about 70 to 50 mol% butadiene is used. , It is possible to crosslink with a commonly used organic peroxide, and at the time of crosslinking, a polyfunctional unsaturated compound such as triallyl isocyanurate, triallyl cyanurate, and trimethylolpropane trimethacrylate is used as a crosslinking aid. It is preferable to use them together. In the compound, in addition to the cross-linking agent and the cross-linking aid, fillers such as talc and graphite, processing aids such as stearic acid and paraffin wax,
An acid acceptor such as zinc oxide and magnesium oxide, an antiaging agent and the like are appropriately mixed and used.

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 to 1000 unvulcanized nitrile rubber compound is added.
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 nitrile rubber compound (in the case of about 500 μm or less)
Or a method to put out the rubber sheet with a calendar roll
(In case of about 500 μm or more) etc. are applied.

The incorporation of the inorganic filler in the nitrile rubber compound is effective in preventing the adhesive layer from peeling 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 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 law and the like wet process white carbon produced by such a specific surface area (by nitrogen adsorption method) of about 20 to 200 m ² / g, preferably is used of about 30 to 100 m ² / g. Calcium silicate has a specific surface area of about 20 ~
A 150 m ² / g, weakly alkaline one is used. Also, as calcium carbonate, the specific surface area is about 5 to 100 m ² /
g, an average particle size of about 10 μm or less, and a 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 120 parts by weight, per 100 parts by weight of nitrile rubber. If the blending ratio is less than this, it is difficult to prevent the occurrence of foaming or peeling of the blister in the liquid contact portion and the vapor portion during the non-immersion semi-immersion. On the other hand, if it is used at a blending ratio higher than this, high temperature, vibration after air heating aging for a long time,
The rubber layer is cracked, cracked, or peeled off due to impact or bending.

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 or the like 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 nitrile rubber.

Vulcanization of a nitrile rubber compound prepared by kneading with a kneader such as an intermix, a kneader, a Banbury mixer or an open roll is generally about 150 to 230 ° C., about 20 to 100 Kgf / cm ² , about 0.5. It is carried out by pressure vulcanization for 30 minutes. After that, for the purpose of preventing adhesion of the vulcanized rubber surface, graphite, carbon black,
Paraffin wax is the main component, and a binder such as cellulose, acrylic resin, polybutadiene resin, etc. is added to this, and a dispersion that is dispersed in a solvent such as toluene is applied to form a non-adhesive layer with a thickness of about 2 to 10 μm. The formation prevents seizure and adhesion.

[0025]

EFFECTS OF THE INVENTION The rubber laminated metal sheet according to the present invention does not peel off in the adhesive layer and the rubber layer even during long-term air heating aging or immersion in a high temperature antifreeze solution, and is particularly exposed to high temperature of 175 ° C. Since the rubber is not deteriorated even after being subjected, the rubber layer is not cracked, cracked or peeled by vibration, impact or bending. 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. Further, the material cost can be kept low as compared with the hydrogenated nitrile rubber laminated metal plate having the same performance.

[0026]

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 complex 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 (Japan 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 ( Seiko Chemicals Non-flex RD) 2〃 Triallyl isocyanurate 2〃 1,3-bis (tertiary butylperoxy) isopropylbenzene 2.5〃 Fluorine rubber (DuPont product Viton A-100) 10〃

On this adhesive layer, a rubber solution (solid 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, and the mixture was heated 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 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 solution of rubber laminated metal plates (non-amine long life coolant; Toyota genuine LLC ) Half-diluted in 50% by volume water diluted solution, and in a pressure vessel at 150 ° C for 500 hours, check for peeling at the gas-liquid interface (gas phase part) and liquid phase immersion part (wetted part). It was judged visually.

Example 2 In Example 1, the same amount of Viton LM manufactured by DuPont was used as the fluororubber in the nitrile compound.

[0032]

Comparative Example 1 In the nitrile rubber compound of Example 1, no fluororubber was used.

[0034]

Comparative Example 2 In Example 1, 33.3% by weight of a phenolic adhesive (Chemlock 205 manufactured by Road Far East Co., Ltd.) was used as the adhesive.
A methyl ethyl ketone solution was used.

The measurement results of the above Examples and Comparative Examples are shown in the following table. Table Example Comparative Example measurement items 1 2 1 2 peeling in [air heating aging test] no slight peeling in the bending test large large [antifreeze Immersion Test] None None None peeling in the gas-liquid interface large liquid immersion unit None None None Large

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-265764 (JP, A) JP-A 8-302323 (JP, A) JP-A 61-62538 (JP, A) JP-A 6- 335990 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (4)

(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.
A rubber laminated metal plate obtained by laminating a vulcanized product layer of nitrile rubber containing fluororubber via an adhesive containing an A-type epoxy resin . 2. Nitrile rubber further containing fluororubber
A compound-added adhesive is used.
The rubber laminated metal plate described. 3. The rubber laminated metal plate according to claim 2, wherein at least one of silicic acid, calcium silicate and calcium carbonate is further added to the nitrile rubber compound containing fluororubber. 4. The addition of nitrile rubber containing fluororubber.
In the sulphate layer, silicic acid, calcium silicate and calcium carbonate
The method according to claim 1, wherein at least one kind of sium is added.
Rubber laminated metal plate.