JP2009190171A - Laminated body whose surface is non-adhesive and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent sticking of a rubber layer and falling off of a solid lubricant without impairing the inherent sealing property of rubber, wear of a rubber layer due to outflow of a binder that becomes liquid in a high temperature environment, Provided is a laminate that is unlikely to deteriorate.
A non-adhesive treatment coating composition comprising a solid lubricant, a fluororubber, a vulcanizing agent, and a liquid carrier, wherein the non-adhesive treatment layer is laminated on a rubber layer. A layered product formed by painting an object and having a thickness of less than 5 μm.
[Selection figure] None

Description

The present invention relates to a laminate having a non-adhesive surface and its use.

In the engine gasket field, rubber coated metal gaskets have recently been used as an alternative to asbestos materials. This is a sealing material that takes advantage of both the elasticity produced by the beaded metal and the micro-sealability of rubber.

Since such a rubber-coated metal gasket has a surface covered with a rubber layer, there is a problem that the rubber layers are likely to adhere to each other in the manufacturing process. In addition, since the temperature change due to repeated operation and stop of the engine is large in the gasket insertion portion of the engine, the joint surface between the engine and the gasket may be displaced due to a difference in expansion coefficient or the like. Further, the rubber-coated metal gasket has a problem that the surface thereof is a rubber layer and has a large frictional resistance and is difficult to slide, so that it is difficult to absorb the stress generated on the joint surface and the rubber layer is easily damaged.

Therefore, the following methods have been tried for the purpose of preventing the rubber layer from sticking.
1) Applying a solid lubricant and providing a non-adhesive layer on the rubber layer (Patent Document 1)
2) Apply a liquid lubricant such as wax and provide a non-adhesive layer on the rubber layer (Patent Document 2)
3) A mixture of a solid lubricant and a thermosetting resin such as epoxy resin or phenol resin is applied, and a non-adhesive layer is provided on the rubber layer (Patent Document 3).

However, in the above method 1), since the solid lubricant is not held by the binder, the solid lubricant contaminates the press mold during the gasket processing or the load by the solid lubricant is generated when a high load stress occurs. There is a problem that the rubber seal layer is worn and the sealing performance of the gasket is lowered.

In the method 2), when the operating temperature environment is severe, there is a problem that the binder flows out with the passage of time and the effect of reducing the frictional force is impaired.

In the above method 3), the resin used as the binder layer for holding the solid lubricant is urethane resin, silicon resin, epoxy resin and phenol resin, and the film using these resins does not have elasticity, so the film becomes hard. There is a problem inferior in micro-sealability.
JP-A-6-081956 JP-A-11-001678 JP2002-130480

The object of the present invention is to prevent the rubber layer from sticking and the solid lubricant from falling off without impairing the inherent sealing properties of the rubber in view of the above-mentioned current situation, and also from the outflow of the binder that becomes liquid in a high temperature environment. An object of the present invention is to provide a laminate in which layer wear is less likely to occur.

The present invention is a laminate in which a non-adhesive treatment layer is laminated on a rubber layer, and the non-adhesion treatment layer comprises a solid lubricant, a fluororubber, a vulcanizing agent, and a liquid carrier. It is a layer formed by painting an object, and has a thickness of less than 5 μm.
The present invention is a laminate in which the laminate of the present invention is provided on a metal plate.
This invention is an engine gasket which consists of a laminated body of the said invention.
The present invention is described in detail below.

The laminate of the present invention is obtained by laminating a non-adhesive treatment layer on a rubber layer.
In the laminated body, the rubber layer is provided to provide sealing properties, and can be generally formed by a known method such as painting or compression molding of a rubber composition.
The rubber constituting the rubber composition is not particularly limited as long as it can form a coating film. For example, fluorine rubber, NBR, hydrogenated NBR, SBR, acrylic rubber, chloroprene rubber, butyl rubber, EPM, EPDM, etc. Among them, fluororubber is preferable from the viewpoint of heat resistance and chemical resistance. Since the non-adhesive treatment layer in the present invention contains fluororubber, it has a good affinity with the fluororubber and has high adhesion between the rubber layer and the non-adhesive treatment layer, which is preferable.
For example, the rubber layer is coated on the base material described later by a normal coating method such as spray coating, flow coating, dip coating, dispenser coating, screen coating, and the like. Can be formed.
The rubber composition may contain a known additive such as a vulcanizing agent described later, and can be appropriately prepared depending on the type of the composition to be used.
The rubber layer can be formed, for example, by applying a rubber composition, drying it, and baking it.
The conditions for the application, drying and baking can be appropriately set according to the composition of the rubber composition to be used.

In the laminate of the present invention, the non-adhesive treatment layer is formed by coating a non-adhesive treatment coating composition comprising a solid lubricant, fluororubber, a vulcanizing agent and a liquid carrier, and has a thickness of less than 5 μm. It is what is.
Although a coating composition containing fluororubber and fluororesin is known, a thin coating film having a thickness of less than 5 μm is not formed on the rubber layer. That is, it is only known as a prior art that a coating film of 5 μm or more is formed by such a coating composition, and the fluororesin is unevenly distributed on the surface to obtain non-adhesiveness and lubricity of the surface. .
In the present invention, a thin coating film having a solid lubricant content of less than 5 μm is formed on the rubber layer to form a coating film in which the solid lubricant is not unevenly distributed on the surface. By curing the fluororubber in such a state, the solid lubricant can be uniformly present on the surface and can be stably held, the original sealing property of the rubber layer is not impaired, The solid lubricant can be prevented from falling off, and the deterioration of the rubber layer due to high-temperature and long-time firing can be prevented.

Each component contained in the coating composition for non-adhesive treatment in the present invention will be described below.
Solid lubricant In the coating composition for non-tack treatment, the solid lubricant is added to impart non-tackiness and the like to the resulting coating film.
The solid lubricant is not particularly limited, but is preferably a fluororesin in terms of heat resistance, abrasion resistance, and the like. In addition to the fluororesin, the solid lubricant may contain one or more of graphite, molybdenum disulfide, tungsten disulfide, graphite fluoride, boron nitride and the like.

Examples of the fluororesin include polytetrafluoroethylene [PTFE], tetrafluoroethylene [TFE] / hexafluoropropylene [HFP] copolymer [FEP], and TFE / perfluoro (alkyl vinyl ether) [PFVE] copolymer. [PFA], TFE / HFP / perfluoro (alkyl vinyl ether) copolymer [EPA], TFE / chlorotrifluoroethylene [CTFE] copolymer [PCTFE], TFE / ethylene [Et] copolymer [ETFE], Polyvinylidene fluoride [PVDF] and the like are mentioned, and among them, PTFE is preferable in terms of heat resistance, wear resistance and the like.

The solid lubricant preferably has an average particle size of 0.1 to 0.5 μm, a more preferable lower limit is 0.15 μm, and a more preferable upper limit is 0.40 μm.
In the present specification, the average particle diameter is a value measured with CAPA700 (centrifugal sedimentation particle size distribution measuring device) manufactured by Horiba.

Fluoro rubber and vulcanizing agent The fluoro rubber retains a solid lubricant as a binder component in the obtained non-adhesive treatment layer, and also maintains heat resistance and oil resistance while maintaining the sealing property of the rubber layer. It is added to improve characteristics such as LLC resistance.
The fluororubber is preferably a fluorine-containing copolymer containing a repeating unit having —CH ₂ — in the main chain.
Examples of the repeating unit having —CH ₂ — include —CF ₂ —CH ₂ —, —CH ₂ —CH ₂ —, —CH ₂ —CH (CH ₃ ) —, and a copolymer thereof. the fluorinated repeating units containing _{no, -CF 2 -CF (CF 3)} - - -CH 2 that may _{be, - CF 2 -CF 2 -,} - CF 2 -CFCl -, - CF 2 -CF ( CF ₂ H) — and —CF ₂ —CF (OR _f ¹ ) — (wherein R _f ¹ is a fluoroalkyl group having 1 to 9 carbon atoms).

Examples of the fluorine-containing copolymer include VDF copolymers such as vinylidene fluoride [VDF] / HFP copolymer, VDF / TFE / HFP copolymer; Et / HFP copolymer, TFE / propylene [ Pr] copolymer and the like.
Examples of the fluorine-containing copolymer include “DAIEL” (trade name, manufactured by Daikin Industries), “Viton” (trade name, manufactured by EI DuPont), “Aphras” (trade name, manufactured by Asahi Glass) It is marketed with the brand names such as.
When the rubber layer is made of fluororubber, the fluororubber used as the binder component of the non-adhesive coating composition is used for the rubber composition because of its good adhesion to the rubber layer. More preferably, it is the same type as the rubber to be used.
The coating composition for non-adhesive treatment may contain only one type of the fluororubber, or may contain two or more types.
The fluorine-containing copolymer preferably has a weight average molecular weight of 5,000 to 200,000.
The said weight average molecular weight is the value calculated | required as a weight average of polystyrene conversion by gel permeation chromatography [GPC].

In the non-adhesive coating composition, the vulcanizing agent is added to promote the formation of a rubber film and strengthen the resulting coating film.
Examples of the vulcanizing agent include polyamines, polyhydroxy aromatic compounds (polyols), peroxides, and the like, among which polyamines are preferable.

Examples of the polyamine vulcanizing agent include triethylenetetramine, tetraethylenepentamine, ethylenediamine, triethylenediamine, ethanolamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxa-2- Aliphatic polyamines such as spiro [5,5] -undecane and salts thereof, aromatic amines such as diaminodiphenylmethane, xylylenediamine, phenylenediamine, diaminodiphenylsulfone, and diaminodiphenyl ether, and salts thereof, modified polyamines, polyamidoamines, etc.
An amino group-containing metal compound of at least one metal selected from the group consisting of Si, Al, Ti and Zr.
Preferred amino group-containing metal compounds include amino group-containing silane coupling agents, amino group-containing aluminum coupling agents, amino group-containing titanium coupling agents, and amino group-containing zirconium coupling agents.
Preferred amino group-containing silane coupling agents include γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N- (trimethoxysilylpropyl) ethylenediamine, N-β-aminoethyl. -Γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane, β-aminoethyl-β-aminoethyl-γ-aminopropyltrimethoxysilane, and the like.
The addition amount of the vulcanizing agent can be appropriately selected according to the type and amount of the fluororubber used, and is not particularly limited.

Liquid carrier In the non-adhesive coating composition, the liquid carrier means a liquid in which other components can be dissolved or dispersed, such as water, a mixed solvent of water and an organic solvent, an organic solvent, and the like. Is mentioned.

In the present invention, the liquid carrier is preferably water in that the rubber layer does not deteriorate. When water is used as the liquid carrier, an aqueous dispersion containing fluororubber obtained by emulsion polymerization in the presence of a dispersant, fluororubber obtained by pulverization after bulk polymerization, To obtain an aqueous dispersion or the like.

Examples of the dispersant include anionic surfactants such as lauryl sulfate, perfluoroalkylcarboxylate, and ω-hydroperfluoroalkylcarboxylate; nonionic interfaces such as polyethylene glycol derivatives and polyethylene glycol / polypropylene glycol derivatives Activating agents; resin-based dispersants such as alkyl polyethylene glycol ether, alkyl phenyl polyethylene glycol ether, alkyl polyethylene glycol ester, ethylene glycol / propylene glycol copolymer, polyethylene glycol alkyl ester, polycarboxylate, and the like.

Others The coating composition for non-adhesion treatment may further contain a thermosetting resin and a curing agent used in combination as necessary.
The said thermosetting resin is added in order to improve the heat resistance of a laminated body, intensity | strength, etc. in the binder component of the non-adhesion process layer obtained. As said thermosetting resin, an epoxy resin, a phenol resin, etc. are mentioned, for example.
The coating composition for non-adhesive treatment may contain only one kind of the thermosetting resin, or may contain two or more kinds.
Examples of the curing agent for the thermosetting resin include amine-based curing agents, phenol-based curing agents, and acid anhydride-based curing agents.
The addition amount of the said hardening | curing agent can be suitably selected according to the kind and quantity of the thermosetting resin to be used, and is not specifically limited.

The non-adhesive treatment layer has a thickness of less than 5 μm, preferably 3 μm or less, in terms of maintaining sealing properties. The lower limit of the thickness is the particle size of the solid lubricant, preferably 0.1 μm.

Since the thickness of the non-stick treatment layer is in the above range, the non-stick treatment layer is generally a coating film in which particles made of a solid lubricant are dispersed in a matrix made of a binder component.
Since the coating film cures the binder component and retains the solid lubricant, the rubber layer can be prevented from sticking and the solid lubricant falling off without impairing the inherent sealing properties of the rubber. In addition, it is possible to provide a laminate in which the rubber layer is less likely to be worn out and the rubber layer is not deteriorated due to the outflow of the binder that becomes liquid in a high temperature environment.

The non-adhesive treatment layer can be formed by applying the above-mentioned non-adhesive treatment coating composition on the surface of the adherend rubber layer, drying it sufficiently, and baking it.
The coating composition for non-adhesive treatment is not particularly limited, but generally, when the amount of solid lubricant is larger than that of the binder component, the solid lubricant cannot be held by the binder component, and the solid lubricant falls off. Moreover, when there is little solid lubricant with respect to a binder component, sufficient non-adhesiveness cannot be obtained. Since these ratios are determined by the particle size of the solid lubricant to be used and the particle size of the binder component, the range cannot be defined uniformly. As for the ratio of the vulcanizing agent to the binder component, if the vulcanizing agent is large, the pot life is shortened, and if the vulcanizing agent is small, the solid lubricant cannot be retained. Since the amount of the vulcanizing agent relative to the binder component varies depending on the type of vulcanizing agent, the range cannot be defined uniformly.
The application can be performed by a conventionally known method such as the method described for the rubber layer.
The conditions for the drying and baking are not particularly limited, and can be appropriately set according to the composition and amount of the coating composition for non-adhesive treatment to be applied, the composition of the rubber layer, and the like.

The laminated body of this invention can be provided in the metal plate which consists of metals, such as iron, stainless steel, copper, aluminum, brass, for example.
A laminate in which the laminate of the present invention is provided on a metal plate is also one aspect of the present invention.
Since the laminate of the present invention is provided with the laminate of the present invention, it has excellent sealing properties, abrasion resistance, heat resistance, oil resistance, LLC resistance and the like.
Examples of the laminate include industrial parts such as oil seals, joints, antenna caps, connectors, gaskets, valve seals, buried bolts, buried nuts, and the like, and are particularly suitable for metal gaskets.
As said metal gasket, engine gaskets, such as a motor vehicle, are mentioned, for example. The engine gasket made of the laminate is also one aspect of the present invention.

Since the laminate of the present invention has the above-described configuration, it prevents the rubber layer from sticking and the solid lubricant from falling off without impairing the inherent sealing properties of the rubber, and is a liquid binder in a high temperature environment. The abrasion of the rubber layer due to the outflow and the deterioration of the rubber layer can be improved.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples and comparative examples.
The amount of the composition in each example and comparative example is based on mass unless otherwise specified.

Example 1
(1) Formation of rubber layer On an aluminum plate that had been washed with acetone in advance, a fluororubber paint (Daikin Industries, Ltd., Daiel DPA-382) was applied with a flow coater and dried at 100 ° C for 30 minutes. Firing was performed at 200 ° C. for 30 minutes to obtain a coated plate having a rubber layer thickness of 25 μm.
(2) Preparation of coating composition for non-adhesive treatment Fluororesin aqueous dispersion ^{Note 1)} (Fluororesin content 60%) 100 parts Fluororubber aqueous dispersion ^{Note 2)} (Fluororubber content 60%) 100 parts Aminosilane 6 Part water 3800 parts Note 1) Contains polytetrafluoroethylene [PTFE] as fluororesin.
Note 2) As fluororubber, vinylidene fluoride [VDF] / tetrafluoroethylene [TFE] / hexafluoropropylene [HFP] elastic copolymer (hereinafter simply referred to as fluororubber) is contained.
(3) Formation of non-adhesive treatment layer The coated plate obtained in (1) is dip-coated at room temperature on the non-adhesive treatment paint obtained in (2) and then dried at 80 to 100 ° C. for 5 minutes. Thereafter, the laminate was baked at 200 ° C. for 5 minutes to obtain a laminate having a non-adhesive treatment layer having a thickness of 1 μm.

Comparative Example 1
The coated plate obtained in Example 1 (1) was used as the laminated plate of Comparative Example 1.

Comparative Example 2
PTFE powder was added to a solution obtained by diluting a phenol resin (manufactured by DIC Phenolite TD2093) to 3% with a methyl ethyl ketone solvent as a non-adhesive coating material on the rubber layer of the coated plate obtained in Example 1. (Daikin Kogyo Co., Ltd.) is added in the same amount as the phenolic resin, dip-coated at room temperature on the dispersed paint, then dried at 80-100 ° C. for 5 minutes, then baked at 200 ° C. for 5 minutes, and 1 μm thick A laminate having an adhesive treatment layer was obtained.

About the laminated board created by the Example and the comparative example, the non-adhesiveness of the coating-film surface, abrasion resistance, and a softness | flexibility were evaluated as follows.
<Non-tackiness test on coating surface>
1-1) The laminate was cut out with a width of 2 cm and overlapped so that the coating surfaces overlap each other in an area of 2 cm × 3 cm, and the load was 1 kg, 200 ° C., and held for 1 hour (adhesion between coatings).
1-2) The laminate was cut out with a width of 2 cm, and a separately prepared aluminum plate was overlapped with an area of 2 cm × 3 cm so as to overlap the painted surface, and the load was maintained at 1 kg, 200 ° C. for 1 hour (coating film and metal Stickiness).
2) For the laminates laminated under the above conditions, the tensile strength was measured at room temperature using a universal testing machine (manufactured by Shimadzu Corporation) according to the tensile shear bond strength test method of JIS K6850. The adhesive strength was evaluated.

<Friction and abrasion test of coating surface>
The laminate was cut out at 3 cm × 5 cm, and the dynamic friction coefficient was measured using a pin-on-disk type friction wear tester (Reska FPR2000) at 200 ° C. under a load of 30 g, a rotation radius of 10 mm, and 20 rpm. .

<Softness test of coating film>
The laminate was cut out with a width of 2 cm, set on a JISK5400 bending tester (manufactured by Otsugi Equipment Co., Ltd.), bent at 180 °, and confirmed whether cracks occurred in the coating film.

The results of each test are summarized in Table 1.

As shown in Table 1, the laminate of Example 1 exhibits non-adhesiveness, and is superior to the untreated laminate (Comparative Example 1) in friction and abrasion resistance, and is a laminate using a conventional treatment agent. It was confirmed that it was comparable to the plate (Comparative Example 2) and more flexible than the laminate of Comparative Example 2.

Since the laminate of the present invention has the above-described configuration, it prevents the rubber layer from sticking and the solid lubricant from falling off without impairing the inherent sealing properties of the rubber, and is a liquid binder in a high temperature environment. The abrasion of the rubber layer due to the outflow and the deterioration of the rubber layer can be improved.

Claims (4)

A laminate in which a non-adhesive treatment layer is laminated on a rubber layer,
The non-adhesive treatment layer is a layer formed by coating a coating composition for non-adhesive treatment comprising a solid lubricant, fluororubber, vulcanizing agent and liquid carrier, and has a thickness of less than 5 μm. A laminate characterized by the following. The laminate according to claim 1, wherein the solid lubricant is a fluororesin. A laminate having the laminate according to claim 1 or 2 provided on a metal plate. An engine gasket comprising the laminate according to claim 3.