JP2008213354A - Rubber metal composite body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber metal composite body with improved heat resistance of adhesion in the rubber metal composite body made by successively laminating a silane undercoat agent, a phenol resin topcoat agent and a nitrile rubber on a metal sheet. <P>SOLUTION: In the rubber metal composite body, the silane undercoat agent is a hydrolyzate condensate of an organoalkoxysilane, and an undercoat agent in which 250-1,100 pts.wt. organometallic compound per 100 pts.wt. of the hydrolyzate condensate are added is used. This rubber metal composite exhibits excellent heat resistance of adhesion when it is used as a gasket to be used for the application where heat resistance of approximately 150°C or higher is required, in particular, as a gasket for an engine cylinder head or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber metal composite. More specifically, the present invention relates to a rubber metal composite used for gaskets and the like that require heat resistance of 150 ° C. or higher.

The present applicant has previously described a rubber metal laminated gasket with excellent liquid resistance against water, ethylene glycol, alcohol, LLC (Long Life Coolant), etc. as a silane-based primer, a phenolic resin-based adhesive on the metal plate, and A rubber metal laminated gasket in which nitrile rubber is laminated sequentially is proposed.
JP 2003-334485 A

  In the rubber metal laminated gasket proposed here, an organometallic compound is further added to the silane-based primer at a ratio of about 100 parts by weight or less, preferably about 20 to 80 parts by weight per 100 parts by weight of the hydrolytic condensate. In this case, the liquid resistance effect is said to be more prominent, but if it is used in a proportion higher than this, the compatibility with the top coat and rubber becomes worse. It is stated that adhesion will be reduced.

  However, when a silane-based primer using an organometallic compound in such a proportion is used, the adhesive heat resistance is not sufficient, and the rubber metal laminated gasket has a heat resistance of about 150 ° C. or higher. When it is used for a required engine cylinder head gasket or the like, further improvement in its adhesive heat resistance is required.

  An object of the present invention is to provide a rubber metal composite obtained by sequentially laminating a silane-based undercoat agent, a phenol resin-based topcoat adhesive, and a nitrile rubber on a metal plate, which has improved adhesion heat resistance. is there.

  The object of the present invention is to add the organometallic compound in an amount of 250 to 1100 parts by weight per 100 parts by weight of the hydrolyzed condensate in the rubber metal composite, in which the silane primer is a hydrolyzed condensate of organoalkoxysilane. This is achieved by the rubber metal composite in which the primer is used.

  The rubber metal composite according to the present invention exhibits excellent adhesion heat resistance when used as a gasket used for applications requiring heat resistance of about 150 ° C. or more, particularly as an engine cylinder head gasket. .

  As the metal plate, a stainless steel plate, a mild steel plate, an aluminum plate, an aluminum die cast plate or the like is used, and a stainless steel plate such as SUS304, SUS301, or SUS430 is preferably used. Since the plate thickness is used for gaskets, a thickness of about 0.1 to 2 mm is generally used.

On these metal plates, a silane-based primer is first applied. As the silane-based primer, a hydrolytic condensate of organoalkoxysilane is used. Here, organoalkoxysilane of the general formula R ^'is represented by Si (OR) _3, R is a lower alkyl group such as a methyl group, an ethyl group, ^R' is a methyl group, an ethyl group, 3-aminopropyl group N- (2-aminoethyl) -3-aminopropyl group, N-phenyl-3-aminopropyl group, vinyl group, 3-methacryloxypropyl group, 3-glycidoxypropyl group, 3-mercaptopropyl group, etc. It is. The hydrolysis-condensation reaction of organoalkoxysilane is performed by heating to about 40 to 80 ° C. in the presence of an acid catalyst such as formic acid in the presence of water for hydrolysis.

  As such a hydrolysis-condensation product, a copolymer oligomer of an amino group-containing alkoxysilane and a vinyl group-containing alkoxysilane is preferably used. Examples of the amino group-containing alkoxysilane that is one component of the copolymer oligomer include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane. N-β- (aminoethyl) -γ-aminopropyltriethoxysilane and the like are used. As the vinyl group-containing alkoxysilane which is another component, for example, vinyltrimethoxysilane, vinyltriethoxysilane or the like is used.

  In the oligomerization reaction, 25 to 400 parts by weight, preferably 50 to 150 parts by weight of vinyl group-containing alkoxysilane and 20 to 150 parts by weight of water for hydrolysis are used with respect to 100 parts by weight of amino group-containing alkoxysilane. . When the vinyl group-containing alkoxysilane is used in a larger proportion, the compatibility with the top coat or rubber is deteriorated and the adhesiveness is lowered. On the other hand, when it is used in a smaller proportion, the water resistance is lowered. It becomes like this.

  In the oligomerization reaction, these are charged into a reactor having a distillation apparatus and a stirrer, and stirred at about 60 ° C. for about 1 hour. Thereafter, an acid such as formic acid or acetic acid is added within 1 hour to about 1 to 2 moles per mole of amino group-containing alkoxysilane. The temperature at this time is kept at about 40 to 65 ° C. The mixture is further stirred for 1 to 5 hours to allow the reaction to proceed, and at the same time, the alcohol produced by hydrolysis is distilled under reduced pressure. Distillation is terminated when only distilled water is present, and then diluted and adjusted such that the silane concentration is 30 to 80% by weight, whereby the desired copolymer oligomer is obtained. This copolymer oligomer is an oligomer having a degree soluble in an alcohol-based organic solvent such as methanol or ethanol.

  In these silane-based primer, an organometallic compound is further added and used. Examples of organometallic compounds include ethylacetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate), aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum tris (acetylacetate), and other organoaluminum compounds, isopropoxytitanium bis ( Organic titanium compounds such as ethyl acetoacetate), 1,3-propanedioxytitanium bis (ethylacetoacetate), diisopropoxytitanium bis (acetylacetonate), titanium tetraacetylacetonate, di-n-butoxyzirconium bis (acetylacetonate) And organic zirconium compounds such as di-n-butoxyzirconium bis (ethylacetoacetate). These organometallic compounds, particularly those having an ethyl acetoacetate or acetylacetonate group, improve the compatibility and adhesiveness with the topcoat and rubber at the time of high compounding.

  These organometallic compounds are used in a ratio of about 250 to 1100 parts by weight, preferably about 300 to 1000 parts by weight, per 100 parts by weight of the hydrolysis condensate. Addition of the organometallic compound in such a use ratio improves the adhesion heat resistance, whereas when used in a ratio outside this range, the adhesion heat resistance decreases.

  The silane-based primer having the above-mentioned components as essential components is generally about 0.2 to 3% by weight of a mixed solvent of an alcohol-based organic solvent such as methanol, ethanol or isopropanol, or a ketone-based organic solvent such as acetone or methyl ethyl ketone and water. Prepared and used as a concentrated solution. The organic solvent and water are used in a mixture such that the former is about 100 to 80% by weight and the latter is about 0 to 20% by weight. When water is used in combination, the hydrolysis condensate further increases in molecular weight, and a strong film can be formed.

  The silane-based primer is dipped on a metal plate, applied to a film thickness of about 0.1 to 10 μm by a method such as spraying, brushing, or roll coating, dried at room temperature, and then about 1 at about 100 to 250 ° C. It is baked for about 20 minutes.

  In general, a commercially available phenol resin-based topcoat is applied as a vulcanized adhesive on the silane-based undercoat applied on the metal plate. Commercially available products include Toyo Chemical Laboratory product Metalolc N31, Rohm and Haas Company product Sixon 715, Lord Far East Company product Chemlock TS1677-13, and the like. For the topcoat, the same coating method, coating temperature, and coating time as in the case of the basecoat are applied, and an overcoat layer having a film thickness of about 1 to 15 μm is formed.

  As an organic solvent solution of the nitrile rubber compound, an unvulcanized nitrile rubber compound is formed on the adhesive layer thus formed so as to form a one-side vulcanized layer having a thickness of about 5 to 120 μm. Applied. The applied rubber layer is dried at a temperature of room temperature to about 100 ° C. for about 1 to 15 minutes, and after volatilizing methyl ethyl ketone, toluene, xylene or a mixed solvent thereof used as an organic solvent, about 150 to about 150 to Heat vulcanization is performed at 230 ° C. for about 0.5 to 30 minutes, and pressure vulcanization is performed as necessary. The vulcanized nitrile rubber layer preferably has a hardness (durometer A) of 80 or more and a compression set (100 ° C., 22 hours) of 50% or less for use as a gasket, and needs to prevent adhesion. In some cases, an anti-sticking agent can be applied to the surface.

  The nitrile rubber may be not only NBR but also hydrogenated NBR, which can be used as a compound using a sulfur vulcanizing agent such as sulfur or tetramethylthiuram monosulfide, but is preferably an organic peroxide. Used as an unvulcanized nitrile rubber compound using the product as a crosslinking agent. Examples of such peroxide-crosslinked unvulcanized nitrile rubber compounds include the following blending examples.

(Formulation example I)
NBR (medium-high nitrile; JSR product N237) 100 parts by weight
HAF carbon black 10 〃
SRF carbon black 40 〃
Cellulose powder 10 〃
Zinc oxide 10 〃
Stearic acid 1 〃
Microcrystalline wax 2 〃
Anti-aging agent (ODA-NS, Ouchi Emerging Chemicals) 4 〃
Plasticizer (Buyer OT product from Bayer) 5 〃
Organic peroxide (NIPPON OIL & PRODUCTS PERHEXA 25B) 6 〃
N, N-m-phenylene dimaleimide 1 〃

(Composition Example II)
NBR (medium-high nitrile; JSR product N237) 100 parts by weight
HAF carbon black 80 〃
Powdered silica 60 〃
Zinc oxide 5 〃
Stearic acid 1 〃
Anti-aging agent (Ouchi Emerging Chemical Products ODA-NS) 1 〃
Organic peroxide (NIPPON OIL & PRODUCTS PERHEXA 25B) 6 〃
N, N-m-phenylene dimaleimide 1 〃

(Formulation example III)
NBR (medium-high nitrile; JSR product N235S) 100 parts by weight
SRF carbon black 80 〃
Calcium carbonate 80 〃
Powdered silica 20 〃
Zinc oxide 5 〃
Anti-aging agent (Ouchi Emerging Chemical Product Nocrack 224) 2 〃
Triallyl isocyanurate 2 〃
1,3-bis (tert-butylperoxy) isopropylbenzene 2.5 〃
Plasticizer (Buyer OT product from Bayer) 5 〃

(Formulation example IV)
Hydrogenated NBR (Nippon Zeon product Zetpol2010) 100 parts by weight
SRF carbon black 80 〃
Powdered silica 60 〃
Zinc oxide 5 〃
Stearic acid 1 〃
Anti-aging agent (ODA-NS) 1 〃
Organic peroxide (Perhexa 25B) 6 〃
N, N-m-phenylene dimaleimide 1 〃

Next, the present invention will be described with reference to examples.
Reference Example A three-necked flask equipped with a stirrer, heating jacket and dropping funnel is charged with 40 parts of γ-aminopropyltriethoxysilane (weight, the same applies hereinafter) and 20 parts of water, and acetic acid is added so that the pH is 4-5. And stirred for several minutes. While further stirring, 40 parts of vinyltriethoxysilane was gradually added dropwise using a dropping funnel. After completion of dropping, the mixture was heated to reflux at a temperature of about 60 ° C. for 5 hours and cooled to room temperature to obtain a copolymer oligomer.

Example 1
After alkali degreasing the surface of SUS301 steel plate (thickness 0.2mm),
The copolymer oligomer 0.5 parts Titanium tetraacetyl acetate 1.5 parts Methanol 88.0 parts Water 10.0 parts of water were applied and dried at room temperature, followed by baking at 220 ° C. for 5 minutes.

After cooling
Phenolic resin top adhesive 12.0 parts
(Rohm and Haas products Sixson 715-A)
Hexamethylenetetramine-containing curing agent (Sixon 715-B, the company's product) 0.4 parts Methyl ethyl ketone 77.6 parts Methanol 10.0 parts of an overcoat adhesive was applied and dried at room temperature, followed by baking at 210 ° C for 5 minutes.

In this adhesive layer,
Nitrile rubber compound (formulation example I) 25.0 parts Methyl ethyl ketone 7.5 parts Toluene 67.5 parts of rubber solution (solid content concentration 25% by weight) is applied and dried at 60 ° C for 15 minutes. After the vulcanized rubber layer was formed, pressure vulcanization was performed under the conditions of 180 ° C., 5.88 MPa (60 kgf / cm ² ) for 10 minutes to obtain a rubber metal composite.

  About the obtained rubber metal composite, the adhesion evaluation test was done as follows.

  Cut out two test pieces (75 x 15 mm) from the rubber-metal composite produced, and use instant adhesive (Three Bond product 1743) to superimpose the test pieces alternately at their ends (length 10 mm). Finger pressure, bonded and bonded (bonded area 10 x 15 mm), dried for 8 hours at room temperature, then vulcanized rubber layer, topcoat adhesive layer and undercoat layer on stainless steel plate located at both ends of bonded bond A cut with a cutter was made into an adhesive test piece.

  Set this adhesion test piece on a tensile tester (AG-IS manufactured by Shimadzu Corporation), conduct a tensile test under the conditions of ambient temperature, normal temperature, tensile speed of 50 mm / min, and distance between chucks of 50 mm until the adhesion test piece breaks. The maximum load was measured to calculate the adhesive strength, and this was used as the initial adhesive strength. Further, after the cut test pieces were heat-treated at 150 ° C. and 200 ° C. for 70 hours, respectively, adhesion test pieces were similarly prepared, and tensile tests were performed to measure the adhesive strength.

Example 2
In the silane-based undercoat agent of Example 1, one having the hydrolysis condensate amount changed to 0.25 parts and the methanol amount changed to 88.25 parts was used.

Example 3
In the silane-based undercoat agent of Example 1, the hydrolyzed condensate amount was changed to 0.25 parts, the organic titanium compound amount was changed to 2.25 parts, and the methanol amount was changed to 87.5 parts.

Comparative Example 1
In the silane-based undercoating agent of Example 1, an organic titanium compound amount was changed to 2 parts without using a hydrolysis condensate.

Comparative Example 2
In the silane-based undercoat agent of Example 1, the hydrolyzed condensate amount was changed to 1 part, the organic titanium compound amount was changed to 0.5 part, and the methanol amount was changed to 88.5 parts.

Comparative Example 3
In the silane-based primer of Example 1, the hydrolyzed condensate amount was changed to 0.5 part, the organic titanium compound amount was changed to 1 part, and the methanol amount was changed to 88.5 parts.

Comparative Example 4
In the silane-based undercoat agent of Example 1, an organic titanium compound was not used, but the amount of hydrolysis condensate was changed to 2 parts.

Comparative Example 5
In Example 1, 20.0 parts of a silane-based primer as a silane-based primer
(Lord Far East product Chemlock AP-133)
A silane primer comprising 70.0 parts of methanol and 10.0 parts of water was used.

Comparative Example 6
In Example 1, 20.0 parts of a silane-based primer as a silane-based primer
(Toyo Chemical Research Products Metallock S-2)
A silane primer comprising 70.0 parts of methanol and 10.0 parts of water was used.

The measurement results in the above examples and comparative examples are shown in the following table.
table
Adhesive strength (MPa)
Example Initial 150 ° C treatment 200 ° C treatment Example 1 20 20 8
〃 2 20 20 7
〃 3 20 19 8
Comparative Example 1 0 0 0
〃 2 16 17 1
〃 3 19 17 3
〃 4 18 14 0
〃 5 18 12 1
６ 6 19 9 1

Claims (6)

  In a rubber metal laminated gasket in which a silane-based primer, a phenolic resin-based adhesive, and a nitrile rubber are sequentially laminated on a metal plate, the silane-based primer is a hydrolysis condensate of organoalkoxysilane, and the hydrolysis condensation A rubber metal composite comprising an undercoating agent to which 250 to 1100 parts by weight of an organometallic compound is added per 100 parts by weight of a product.   The rubber metal composite according to claim 1, wherein the metal plate is a stainless steel plate.   The rubber metal composite according to claim 1, wherein the hydrolyzed condensate of the organoalkoxysilane is a copolymer oligomer of an amino group-containing alkoxysilane and a vinyl group-containing alkoxysilane.   The rubber metal composite according to claim 1, which is used for applications requiring heat resistance of 150 ° C or higher.   The rubber metal composite according to claim 1 or 4, which is used as a gasket.   The rubber metal composite according to claim 5, which is used as a gasket for an engine cylinder head.