JP2008266355A - Vulcanized adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vulcanized adhesive composition which exhibits excellent durability to water and LLC and can hold a good adhesive strength after the application of a thermal degradation condition, even when used as an adhesive for rubber-metal laminates. <P>SOLUTION: This vulcanized adhesive composition comprises (a) a phenol xylylene resin, (b) a resol type phenolic resin and (c) titanium dioxide and/or zinc oxide. The vulcanized adhesive composition can be used as an adhesive on the production of a rubber-metal laminate comprising stainless steel plate/primer agent/adhesive/rubber laminate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vulcanized adhesive composition. More specifically, the present invention relates to a vulcanized adhesive composition that is effectively used for vulcanization adhesion between metal and rubber.

  Stainless steel is used as the metal material for rubber metal laminated gaskets that require water resistance. However, even if rubber is bonded by applying a vulcanized adhesive directly onto stainless steel, the durability against liquid adhesion is poor. When the immersion test is performed on this, adhesion peeling occurs. As a countermeasure, it has been proposed to improve the resistance to water and LLC by applying chromate treatment to the stainless steel surface as a pretreatment for applying adhesive, but it does not contain hexavalent chromium which adversely affects the human body and the environment. There is a growing demand for free processing.

The present applicant has previously described a rubber metal laminate using a silane-based primer and a surface treatment agent containing three elements of zirconium element, phosphorus element and aluminum element, which has excellent resistance to water and LLC. A metal laminate is proposed. In addition, a vulcanized adhesive composition comprising a phenol xylylene resin excellent in refrigerant resistance, a resol type phenol resin, an unvulcanized nitrile rubber and chlorinated polyethylene as essential components has been proposed.
JP 2003-334485 A JP 2006-218630 A JP 2003-261850 A

  However, when these rubber metal laminates are used as gaskets, it is required to maintain adhesion at a much higher temperature than conventional rubber products. It is difficult to satisfy, and therefore, a rubber metal laminate that satisfies the expected performance in such an application is desired.

  An object of the present invention is to provide a vulcanized adhesive composition capable of maintaining adhesive strength after application of heat deterioration conditions while exhibiting excellent resistance to water and LLC even when used as an adhesive for a rubber metal laminate. Is to provide.

  The object of the present invention is achieved by a vulcanized adhesive composition comprising (a) a phenol xylylene resin, (b) a resol type phenol resin, and (c) titanium oxide and / or zinc oxide. This vulcanized adhesive composition is used as an adhesive for producing a rubber metal laminate comprising a stainless steel plate / undercoat / adhesive / rubber laminate.

  The vulcanized adhesive composition of the present invention exhibits excellent resistance to water and LLC even when used as an adhesive for a rubber metal laminate comprising a stainless steel plate / undercoat / adhesive / rubber laminate. It is possible to maintain the adhesive strength after applying the heat deterioration condition. In addition, when applied to a rubber metal laminate used as an engine head gasket, the rubber layer is hardly peeled off by fretting generated between the engine and the gasket. In addition, the rubber metal laminate of the present invention is effectively used as a sealing material for automobiles, industrial metal gaskets, and the like.

  The phenol xylerin resin as component (a) is a polycondensation reaction product of 1,4-bis (alkoxymethyl) benzene and phenol or a phenol derivative having at least one methylol group at the 2,4-position. Actually, commercially available products such as Meiwa Kasei products MR-7800 can be used as they are.

  As the resol type phenol resin as component (b), a resin obtained by subjecting phenols and formaldehyde to a condensation reaction in the presence of an alkaline catalyst is used. In this case, the phenols include 2 or 3 substitutable nuclear hydrogens in the o-position and / or p-position with respect to the phenolic hydroxyl group such as phenol, p-cresol, m-cresol, p-tert-butylphenol, etc. Phenols having atoms or a mixture thereof are used, and alkaline catalysts include amine catalysts such as hexamethylenetetramine, triethylamine, triethanolamine, piperazine, ammonia, alkali metal hydroxides, magnesium hydroxide, and the like. Used. Among these resol type phenol resins, those prepared from a mixture of m-cresol and p-cresol and formaldehyde are preferably used.

  The resol type phenol resin is used in a ratio of about 1 to 1000 parts by weight, preferably about 10 to 300 parts by weight, with respect to 100 parts by weight of the phenol xylerin resin. When the resol type phenol resin is used at a higher ratio, the heat resistant adhesiveness is lowered. On the other hand, when the resol type phenol resin is used at a lower ratio, the water resistant adhesiveness is lowered.

  Component (c), titanium oxide and zinc oxide, can be used alone or in combination. Titanium oxide and zinc oxide are used in a proportion of 1 to 1000 parts by weight, preferably 10 to 300 parts by weight, based on 100 parts by weight of the phenol xylylene resin. When titanium oxide and zinc oxide are used in a proportion higher than this, the heat resistant adhesiveness is lowered, and when used in a proportion lower than this, the wear resistance is lowered.

  The vulcanized adhesive composition comprising the above components is contained in an organic solvent in which alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone are used alone or in combination. It is dissolved and prepared so that its solid content concentration is about 0.5 to 10% by weight.

  This adhesive composition solution is suitably used as an adhesive layer forming component of a rubber metal laminate. The rubber metal laminate is manufactured by first applying a primer on the stainless steel plate surface by any method such as spraying, dipping, brush coating, roll coater, etc., and drying it at room temperature or under warm air. By baking at about 150 to 250 ° C. for about 0.5 to 3 minutes, an undercoat layer having a coating film thickness of about 0.1 to 2 μm is formed. Next, the adhesive is applied by an arbitrary method in the same manner as the primer, and after drying it at room temperature or under warm air, it is baked at about 100 to 250 ° C. for about 1 to 20 minutes to thereby apply the coating film thickness. An adhesive layer of about 1 to 15 μm is formed. Then, after applying an unvulcanized rubber compound on the adhesive layer and drying at room temperature to 100 ° C for about 1 to 15 minutes to volatilize the solvent, about 150 to 230 ° C for about 0.5 to 30 minutes. A rubber layer having a thickness of about 5 to 120 μm is formed by heating (pressurizing) vulcanization.

  Any stainless steel plate such as SUS304, SUS301, or SUS430 can be selected.

  As the undercoat agent, a silane-based undercoat agent or a surface treatment agent containing three elements of zirconium element, phosphorus element and aluminum element is used. As the silane primer, commercially available silane primers such as Chem Far AP-133 manufactured by Road Far East Co. can be used as they are. A silane-based primer is used. Further, as the surface treating agent containing zirconium element, phosphorus element and aluminum element, the element mass ratio of zirconium and phosphorus is 95: 5 to 60:40, and the element mass ratio of zirconium and aluminum is 90:10 to 10:90. The surface treatment agent is used, which is described in detail in the aforementioned Patent Document 2.

  As the rubber, nitrile rubber or hydrogenated nitrile rubber is used, and a compound containing various necessary compounding agents is prepared as an organic solvent solution such as methyl ethyl ketone, toluene, xylene or a mixed solvent thereof, and then bonded. It is applied on the agent layer. As such a (hydrogenated) nitrile rubber compound, a vulcanizate having a hardness (durometer A) of 80 or more and a compression set (100 ° C., 22 hours) of 50% or less is preferably used.

  An anti-sticking agent can be applied to the rubber surface for the purpose of preventing the rubber from sticking to the obtained rubber metal laminate.

  Next, the present invention will be described with reference to examples.

Examples 1-6, Comparative Examples 1-6
On an alkali-degreased SUS301 stainless steel plate (thickness 0.2 mm), apply a primer of any of the following A to C to a basis weight of 100 to 800 mg / m ² and dry at room temperature, then 220 ° C The baking process was performed for 5 minutes.
[Undercoat]
A: Silane primer (Chemlock AP-133)
B: Silane-based primer (copolymer oligomer solution consisting of 2.5 parts by weight of copolymer oligomer, 87.5 parts by weight of methanol and 10.0 parts by weight of water)
The copolymer oligomer was charged with 40 parts by weight of γ-aminopropyltriethoxysilane and 20 parts by weight of water in a three-necked flask equipped with a stirrer, a heating jacket and a dropping funnel, and acetic acid was added so that the pH was 4-5. In addition, the mixture is stirred for several minutes, and while further stirring, 40 parts by weight of vinyltriethoxysilane is gradually dropped using a dropping funnel, and after completion of dropping, the mixture is heated to reflux at a temperature of about 60 ° C. for 5 hours. It was manufactured by.
C: Surface treatment agent containing zirconium element, phosphorus element, and aluminum element This is an ammonium zirconium carbonate so that the element mass ratio of Zr, P, Al in the surface treatment agent film is 30: 2: 68. What adjusted the quantity of phosphoric acid and an alumina, and adjusted pH to 6-10 using ammonium hydroxide was used.

On the steel sheet coated with primer, cooled after baking treatment, apply the topcoat adhesive of any of the following 1 to 6 so that the coating amount is 400 mg / m ² , dry at room temperature, and then at 210 ° C. for 5 minutes. Was baked. The unit of each component is parts by weight, and the value in parentheses indicates the solid content weight.
[Topcoat adhesive]
Topcoat adhesive I to V:
Topcoat adhesive component I II III IV V
Phenol xylerin resin 100 100 100 100 100
(Maywa Kasei products MB-7800)
Resol type phenol resin 200 200 40 500 40
(Gunei Chemical Products PL-2108: 50% methanol solution) (100) (100) (20) (250) (20)
Titanium oxide 90 10 90 90
Zinc oxide 10 90 10 10
Unvulcanized nitrile rubber (Japanese synthetic rubber product N-237) 40
Chlorinated polyethylene (Daiso Z-200 chlorine content 67%) 20
Toluene 1865
Methyl ethyl ketone 5600 5600 4160 8550 1865

Topcoat adhesive VI: Rohm and Haas company product Sixon 715 (adhesive for nitrile rubber: adhesive made of novolac-type phenol resin and resol-type phenol resin)

On this vulcanized adhesive coated steel sheet, a 25% by weight toluene-methyl ethyl ketone (9: 1 weight ratio) mixed solvent solution of nitrile rubber compound with the following composition was applied and dried at 60 ° C. for 15 minutes to have a thickness of 20 μm on one side. After the unvulcanized rubber layer was formed, pressure vulcanization was performed under conditions of 180 ° C., 60 kgf / cm ² (5.88 MPa) for 10 minutes, and a nitrile rubber-metal laminated gasket material was produced.
[NBR composition]
NBR (JSR product N237) 100 parts by weight
HAF carbon black 10 〃
SRF carbon black 40 〃
Cellulose powder 10 〃
Zinc flower 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, Nm-Phenylenedimaleimide 1 〃

The gasket material was evaluated for adhesive strength, heat-resistant adhesiveness, wear resistance, and heat-resistant wear resistance.
Adhesive strength: Measures shear adhesive strength based on automotive sealant test method (JIS K6830). Heat resistant adhesiveness: After heating at 200 ° C for 72 hours, evaluates the above adhesive strength. Abrasion resistance: Low load friction tester (Reska Measures the number of reciprocating motions until the metal is exposed according to the pin-on-disk wear test method (JIS T0303) for artificial joint materials using the product FPR2000R). Evaluate the above wear resistance

The obtained results are shown in the following table together with the combination of the primer and the top coat adhesive.
table
Example Comparative Example
1 2 3 4 5 6 1 2 3 4 5 6
Primer ABCCCCABCABC
Topcoat adhesive III II III IV VVV VI VI VI

Adhesive strength (MPa) 18 22 20 20 20 20 20 20 20 18 18 18
Heat resistant adhesive (MPa) 9 13 10 10 15 9 2 4 5 1 2 5
Abrasion resistance (times) 650 700 900 800 800 800 500 500 600 700 700 700
Heat wear resistance (times) 280 300 500 500 550 500 40 80 120 20 60 110

Claims (8)

  A vulcanized adhesive composition comprising (a) a phenol xylylene resin, (b) a resol type phenol resin, and (c) titanium oxide and / or zinc oxide.   2. The composition according to claim 1, comprising (b) 1 to 1000 parts by weight of a resol type phenolic resin and (c) 1 to 1000 parts by weight of titanium oxide and / or zinc oxide per 100 parts by weight of the phenol xylylene resin. Vulcanized adhesive composition.   A rubber metal laminate comprising a stainless steel plate / undercoat / adhesive / rubber laminate using the vulcanized adhesive composition according to claim 1 or 2 as an adhesive.   4. The rubber metal laminate according to claim 3, wherein the primer is a silane coupling agent or a metal surface treating agent containing three elements of zirconium element, phosphorus element and aluminum element.   The rubber metal laminate according to claim 3, wherein the rubber is nitrile rubber or hydrogenated nitrile rubber.   6. The rubber metal laminate according to claim 5, further comprising an adhesion preventing layer formed on the rubber surface.   The rubber metal laminate according to any one of claims 3 to 6, which is used as a gasket.   The rubber metal laminate according to claim 7, which is used as an engine head gasket.