KR102743191B1 - Paint compositions and paint articles - Google Patents

Abstract

A paint composition is provided which provides a coating film having excellent non-adhesiveness and scratch resistance. The paint composition comprises a fluororubber, a vulcanizing agent, a solid lubricant, and an organic solvent, wherein the solid lubricant comprises a solid lubricant (A) and a solid lubricant (B) different from the solid lubricant (A).

Description

Paint compositions and paint articles

The present disclosure relates to a paint composition and a painted article.

Since the surface of a rubber-coated painting product is covered with a rubber layer, there is a problem that the rubber layers are likely to stick to each other during the manufacturing or storage process. Therefore, in order to prevent the rubber layers from sticking, a material that provides a non-adhesive layer on the rubber layer has been proposed.

Patent Document 1 describes providing a non-adhesive treatment layer formed from a non-adhesive treatment paint composition containing a fluororesin (solid lubricant), fluororubber, an amino group-containing silane coupling agent, and water on a fluororubber layer.

International Publication No. 2007/135956

The present disclosure aims to provide a coating composition that provides a coating film having excellent non-adhesiveness and scratch resistance, and a painted article having such a coating film.

The present disclosure comprises a fluorine rubber, a vulcanizing agent, a solid lubricant and an organic solvent,

The above solid lubricant relates to a paint composition characterized in that it includes a solid lubricant (A) and a solid lubricant (B) different from the solid lubricant (A).

It is preferable that the above solid lubricant (A) is a fluororesin.

It is preferable that the above solid lubricant (B) is at least one selected from the group consisting of graphite, molybdenum disulfide, tungsten disulfide, graphite fluoride, and boron nitride.

It is preferable that the mass ratio of the above fluorine rubber and the above solid lubricant (fluorine rubber/solid lubricant) is 20/80 to 80/20.

It is preferable that the mass ratio of the above solid lubricant (A) and the above solid lubricant (B) (solid lubricant (A)/solid lubricant (B)) is 50/50 to 90/10.

It is preferable that the above paint composition is a paint composition for non-adhesive treatment.

It is preferable that the above paint composition is a paint composition for non-adhesive treatment of an elastomer layer.

The present disclosure relates to a metal plate and

An elastomer layer provided on one or both sides of the metal plate,

A coating film formed with the coating composition of the present disclosure, provided on the elastomer layer

It also relates to a painted article characterized by having a .

It is preferable that the above elastomer layer is a fluorine rubber layer.

It is preferable that the above-mentioned painted article be a fluorine rubber coat gasket material.

According to the present disclosure, a paint composition providing a coating film having excellent non-adhesiveness and scratch resistance, and a painted article having such a coating film can be provided.

Hereinafter, the present disclosure will be described in detail.

The present disclosure relates to a coating composition comprising a fluororubber, a vulcanizing agent, a solid lubricant and an organic solvent, wherein the solid lubricant comprises a solid lubricant (A) and a solid lubricant (B) different from the solid lubricant (A).

The paint composition of the present disclosure, since it contains the above components, can provide a coating film having excellent non-adhesiveness and scratch resistance.

As the above non-adhesiveness, examples thereof include non-adhesiveness between coatings formed from the coating composition of the present disclosure during manufacture or storage of the coating, or non-adhesiveness to other materials (such as a press mold) that come into contact with the surface of the coating formed from the coating composition of the present disclosure during manufacture or use of the coating.

The paint composition of the present disclosure is also excellent in paint stability.

As the above fluororubber, vinylidene fluoride [VdF] fluororubber, tetrafluoroethylene [TFE]/propylene [Pr] fluororubber, TFE/Pr/VdF fluororubber, ethylene [Et]/hexafluoropropylene [HFP] fluororubber, Et/HFP/VdF fluororubber, Et/HFP/TFE fluororubber, fluorosilicone fluororubber, fluorophosphazene fluororubber, etc. can be mentioned. Among them, VdF fluororubber is preferable.

The above fluorine rubber may be used in one or more types.

As the above VdF-based fluororubber, there may be mentioned a VdF/HFP copolymer, a VdF/TFE/HFP copolymer, a VdF/chlorotrifluoroethylene [CTFE] copolymer, a VdF/CTFE/TFE copolymer, a VdF/perfluoro(alkyl vinyl ether) [PAVE] copolymer, a VdF/TFE/PAVE copolymer, a VdF/HFP/PAVE copolymer, a VdF/HFP/TFE/PAVE copolymer, a VdF/TFE/Pr copolymer, a VdF/Et/HFP copolymer, a VdF/copolymer of a fluorine-containing monomer represented by formula (1), etc.

Equation (1):

(In the formula, Rf is a straight-chain or branched fluoroalkyl group having 1 to 12 carbon atoms)

Examples of the vulcanizing agent include an amine vulcanizing agent, a polyol vulcanizing agent (polyhydroxy aromatic compound, peroxide vulcanizing agent, etc.), but among them, a polyol vulcanizing agent is preferable.

As the above polyol vulcanizing agent, a vulcanizing agent commonly used in polyol vulcanizing fluorine rubber can be used. As the above polyol vulcanizing agent, a compound having at least two hydroxyl groups, particularly phenolic hydroxyl groups, in the molecule and having vulcanizing performance can be exemplified. This compound may also be a polymer compound.

As the polyol vulcanizing agent, among others, phenol derivatives such as bisphenol A, bisphenol AF, and hydroquinone and salts thereof; polyhydroxy compounds having two or more enol-type hydroxyl groups in the molecule such as phenol resin and salts thereof; compounds represented by the formula: R _f ¹ (CH ₂ OH) ₂ (R _f ¹ represents a perfluoroalkyl polyether group), etc. are preferable.

As the above polyol vulcanizing agent, in addition to the above, any commercially available polyol vulcanizing agent for fluorine rubber can be used.

The above polyol vulcanizing agent may be used in one or more types.

In the paint composition of the present disclosure, a vulcanization auxiliary agent may be used to promote vulcanization. Examples of the vulcanization auxiliary agent include quaternary ammonium salts such as alkyl and aralkyl quaternary ammonium salts; quaternary ammonium salts such as quaternary 1,8-diaza-bicyclo[5.4.0]-7-undecenium salt; tertiary amines; and quaternary phosphonium salts.

The amount of the above-mentioned vulcanizing agent and the above-mentioned vulcanizing aid to be added can be appropriately selected depending on the type and amount of the fluororubber used, and is not particularly limited. In addition, two or more types of the above-mentioned may be used in combination.

The coating composition of the present disclosure comprises a solid lubricant (A) as the solid lubricant and a solid lubricant (B) different from the solid lubricant (A). By using different solid lubricants in combination in this way, a coating film having excellent scratch resistance as well as non-stick properties is obtained.

Examples of the above solid lubricants (solid lubricants (A) and (B)) include fluororesin, graphite, molybdenum disulfide, tungsten disulfide, graphite fluoride, boron nitride, etc., and two or more of these can be used in combination.

It is preferable that the above solid lubricant (A) is a fluororesin.

Examples of the fluororesin include polytetrafluoroethylene [PTFE], tetrafluoroethylene [TFE]/hexafluoropropylene [HFP] copolymer [FEP], TFE/perfluoro(alkyl vinyl ether) [PAVE] copolymer [PFA], TFE/HFP/PAVE copolymer [EPA], polychlorotrifluoroethylene [PCTFE], TFE/chlorotrifluoroethylene [CTFE] copolymer, TFE/ethylene [Et] copolymer [ETFE], polyvinylidene fluoride [PVDF], and the like. Among them, PTFE is preferable from the viewpoints of heat resistance, wear resistance, and the like.

The above solid lubricant (B) is preferably at least one selected from the group consisting of graphite, molybdenum disulfide, tungsten disulfide, graphite fluoride, and boron nitride, more preferably at least one selected from the group consisting of graphite and molybdenum disulfide, and even more preferably graphite.

The mass ratio (A/B) of the solid lubricant (A) and the solid lubricant (B) is preferably 50/50 to 90/10, more preferably 55/45 to 85/15, still more preferably 60/40 to 80/20, and particularly preferably 65/45 to 80/20.

The above solid lubricant preferably has an average particle size of 0.1 to 10 µm in order to stably retain and support the film, with a more preferable lower limit being 0.15 µm and a more preferable upper limit being 5 µm.

In this specification, the average particle size is a value measured using CAPA700 (centrifugal sedimentation particle size distribution measuring device) manufactured by Horiba Seisakusho.

The mass ratio of the above fluorine rubber and the above solid lubricant (fluorine rubber/solid lubricant) is preferably 20/80 to 80/20, more preferably 25/75 to 75/25, and even more preferably 30/70 to 70/30.

The organic solvent is not particularly limited, and for example, ketones such as methyl ethyl ketone [MEK], methyl isobutyl ketone [MIBK], diisobutyl ketone [DIBK], diacetone alcohol, cyclohexanone, and isophorone, esters such as butyl acetate and isopentyl acetate, ethers such as diethylene glycol dimethyl ether, hydrocarbons such as toluene and xylene, and amides such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone can be used. The coating composition of the present disclosure may use only one type of the organic solvent, or may use two or more types of organic solvents. The blending amount of the organic solvent can be appropriately adjusted depending on the type of fluororubber blended into the coating composition.

The paint composition of the present disclosure can be used as a solvent-based paint because it contains the organic solvent. Therefore, unlike an aqueous paint using water as a solvent, there is no need to use a surfactant as a dispersant, and the deterioration of the paint film properties due to the surfactant remaining in the paint film can be prevented. In addition, the paint stability is also excellent compared to an aqueous paint.

The paint composition of the present disclosure may contain, in addition to the fluororubber, vulcanizing agent, solid lubricant, and organic solvent described above, a stabilizer. Examples of the stabilizer include orthoesters such as orthoformic acid ester, orthocarbonic acid ester, cyclic orthoester, lactone acetal, orthoformic acid trimethyl ester, orthoformic acid triethyl ester, orthoacetic acid trimethyl ester, orthoacetic acid triethyl ester, orthocarbonic acid trimethyl ester, orthocarbonic acid triethyl ester, orthocarbonic acid tetramethyl ester, and orthocarbonic acid tetraethyl ester; organic acids such as monocarboxylic acids (formic acid, acetic acid, propionic acid, etc.), dicarboxylic acids (oxalic acid, malonic acid, succinic acid, etc.); and the like. The paint composition of the present disclosure may use only one kind of the stabilizer, or may use two or more kinds of stabilizers.

In addition to the above components, the paint composition of the present disclosure may also contain various additives, such as fillers, colorants, antifoaming agents, and surface conditioners.

Examples of the above fillers include carbon black, white carbon, calcium carbonate, barium sulfate, talc, calcium silicate, etc. Among them, carbon black is preferable.

Examples of the above coloring agents include inorganic pigments, complex oxide pigments, etc.

Examples of the above-mentioned defoaming agents include silicone-based defoaming agents and polymer-based defoaming agents.

Examples of the above surface conditioning agent include siloxane compounds, acrylic copolymers, and methacrylic copolymers.

A coating film can be formed by applying the coating composition of the present disclosure to an object to be coated and drying it.

The application of the above paint composition can be performed by a known application method, such as brush application, spray coating, immersion application, flow coating, dispenser coating, or screen coating.

After the above coating and drying, curing may be performed as needed. The above curing may be performed for each layer, or may be performed in a combined manner for multiple layers. In addition, the above curing may be performed simultaneously with the above drying.

The conditions for drying and curing can be appropriately set depending on the type of the paint composition of the present disclosure and the application target.

The paint composition of the present disclosure can be suitably used as a paint composition for non-adhesive treatment, since it provides a coating film having excellent non-adhesiveness and scratch resistance. When the treatment object is an elastomer layer, it can be particularly suitably used as a paint composition for non-adhesive treatment of an elastomer layer, since the non-adhesiveness and scratch resistance of the elastomer layer are further remarkably exhibited. The elastomer layer is preferably a coating film of a paint composition containing an elastomer.

Examples of elastomers that can be used in the above elastomer layer include fluororubber, nitrile rubber, hydrogenated nitrile rubber, styrene-butadiene rubber (SBR), chloroprene rubber (CR), butadiene rubber (BR), natural rubber (NR), isoprene rubber (IR), ethylene-α-olefin rubber, ethylene-α-olefin-nonconjugated diene rubber, chlorinated polyolefin rubber, chlorosulfonated polyolefin rubber, acrylic rubber, ethylene-based acrylic rubber, epichlorohydrin rubber, silicone rubber, butyl rubber (IIR), ethylene-vinyl ester rubber, and ethylene-methacrylate rubber. Among these, fluororubber is preferable.

As the above fluororubber, vinylidene fluoride [VdF] fluororubber, tetrafluoroethylene [TFE]/propylene [Pr] fluororubber, TFE/Pr/VdF fluororubber, ethylene [Et]/hexafluoropropylene [HFP] fluororubber, Et/HFP/VdF fluororubber, Et/HFP/TFE fluororubber, fluorosilicone fluororubber, fluorophosphazene fluororubber, etc. can be mentioned. Among them, VdF fluororubber is preferable.

The above fluorine rubber may be used in one or more types.

As the above VdF-based fluororubber, there may be mentioned a VdF/HFP copolymer, a VdF/TFE/HFP copolymer, a VdF/chlorotrifluoroethylene [CTFE] copolymer, a VdF/CTFE/TFE copolymer, a VdF/perfluoro(alkyl vinyl ether) [PAVE] copolymer, a VdF/TFE/PAVE copolymer, a VdF/HFP/PAVE copolymer, a VdF/HFP/TFE/PAVE copolymer, a VdF/TFE/Pr copolymer, a VdF/Et/HFP copolymer, a VdF/copolymer of a fluorine-containing monomer represented by formula (1), etc.

Equation (1):

(In the formula, Rf is a straight-chain or branched fluoroalkyl group having 1 to 12 carbon atoms)

The present disclosure also relates to a painted article characterized by having a metal plate, an elastomer layer provided on one or both sides of the metal plate, and a coating film formed of the coating composition of the present disclosure described above provided on the elastomer layer.

The painted article of the present disclosure has a coating film formed from the paint composition of the present disclosure, and therefore has excellent non-adhesiveness and scratch resistance.

As the above metal plate, there can be mentioned a plate including iron; stainless steel; aluminum; copper; brass; titanium; and a plated steel plate subjected to zinc plating, aluminum plating, etc. Among these, a stainless steel plate and an aluminum plate are preferable.

As the elastomer constituting the above-described elastomer layer, any of the elastomers exemplified for the elastomer layer that can be processed by the paint composition of the present disclosure described above can be used, and among them, fluororubber is preferable.

It is preferable that the above elastomer layer is a coating film of a paint composition containing the above elastomer.

The above elastomer layer preferably has a thickness of 5 to 50 µm, more preferably 10 to 30 µm.

The above elastomer layer is provided on one or both sides of the metal plate. The above elastomer layer may be provided directly on the metal plate, or may be provided with another layer, such as a primer layer, interposed therebetween.

The coating film formed by the coating composition of the present disclosure is provided on the elastomer layer. The coating film may be provided directly on the elastomer layer or may be provided with another layer therebetween, but it is preferable to provide the coating film directly on the elastomer layer in that the non-adhesiveness and scratch resistance are more remarkably exhibited.

The thickness of the above coating is preferably 0.5 ㎛ or more and less than 10 ㎛, more preferably 1 to 5 ㎛.

On the above coating film, another layer may be provided, but from the viewpoint of more prominently exhibiting non-adhesiveness and scratch resistance, it is preferable not to provide another layer on the above coating film, i.e., the above coating film is the uppermost surface of the painted article.

The painted article of the present disclosure can be manufactured, for example, by applying a paint composition including the elastomer onto the metal plate, drying, applying the paint composition of the present disclosure on the resulting paint film, and drying.

After applying and drying the paint composition forming each layer, curing may be performed as needed. The curing may be performed for each layer, or may be performed in a combined manner for multiple layers. In addition, the curing may be performed simultaneously with the drying.

Conditions for drying and curing can be appropriately set depending on the type of the paint composition and elastomer layer of the present disclosure.

The paint composition and the painted article of the present disclosure can be used in fields requiring non-stickiness, scratch resistance, and the like, and for example, can be used in various sheets and belts; sealing materials such as O-rings, diaphragms, valve seals, gaskets for chemical plants, and engine gaskets; fluid transport members such as chemical-resistant tubes, fuel hoses, and joints; rolls (e.g., fixing rolls, pressing rolls) or return belts for OA devices such as copiers, printers, and facsimiles, and among these, can be suitably used for gaskets. One preferred embodiment is that the painted article of the present disclosure is a fluorine rubber coated gasket material.

Example

The present disclosure is further described in more detail by way of examples, but the present disclosure is not limited to these examples.

<Preparation of a paint composition for non-adhesive treatment>

Example 1

With respect to 100 parts by mass of an elastomer containing a vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene copolymer (fluorine concentration: 68 mass%) as a fluororubber, 37.5 parts by mass of graphite, 112.5 parts by mass of a fluororesin (polytetrafluoroethylene [PTFE]), and 5 parts by mass of an acid agent were kneaded with an open roll to obtain a compound. This compound was mixed with 700 parts by mass of methyl ethyl ketone as an organic solvent, to obtain a compound solution.

Meanwhile, 2 parts by mass of a polyol-based vulcanizing agent and 0.5 parts by mass of a vulcanizing aid were dissolved in a mixed solvent composed of 200 parts by mass of methyl ethyl ketone as an organic solvent and 5 parts by mass of ethanol, to which 2 parts by mass of an orthoacetic acid ester-based compound and 2 parts by mass of an organic acid as a stabilizer were added. This solution was mixed with a previously prepared compound solution using a disper to obtain a non-adhesive treatment paint composition.

Examples 2 and 6

A non-adhesive treatment paint composition was obtained in the same manner as Example 1, except that the blending amounts of fluorine rubber, fluorine resin, and graphite were changed as shown in Table 1 and carbon black was also blended.

Examples 3 to 5

A non-adhesive treatment paint composition was obtained in the same manner as in Example 1, except that the mixing amounts of fluorine rubber, fluorine resin, and graphite were changed as shown in Table 1.

Examples 7 to 10

A non-adhesive treatment paint composition was obtained in the same manner as in Example 1, except that the graphite was changed as shown in Table 1.

Comparative Example 1

A non-adhesive treatment paint composition was obtained in the same manner as in Example 1, except that the mixing amounts of fluorine rubber, fluorine resin, and graphite were changed as shown in Table 1.

Comparative Example 2

A non-adhesive treatment paint composition was obtained by mixing 100 parts by mass of an aqueous dispersion (fluorine rubber content 60 mass%) of fluororubber (vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene copolymer), 100 parts by mass of an aqueous dispersion (fluorine resin content 60 mass%) of fluororesin (polytetrafluoroethylene [PTFE]), 6 parts by mass of an amino group-containing silane coupling agent, and 3,800 parts by mass of water.

<Production of test specimens (painted items)>

A fluorine rubber paint (diisobutyl ketone solution of VdF/HFP copolymer) was applied to an aluminum plate that had been previously cleaned with acetone using a flow coater, dried at 100°C for 30 minutes, and then baked at 200°C for 30 minutes to obtain a painted plate with a rubber layer thickness of 25 μm.

The coating plate obtained above was immersed in the non-adhesive treatment coating composition obtained in the examples and comparative examples at room temperature, then dried at 80 to 100°C for 5 minutes, and then baked at 200°C for 5 minutes to obtain a test piece (coated article) having a non-adhesive treatment layer having a thickness of 1 μm.

Each property was evaluated by the following method. The results are shown in Table 1.

<Non-adhesion test (non-adhesion between coatings)>

The above test piece was cut into 2 cm widths, the 2 cm x 3 cm film surfaces were overlapped, and maintained for 1 hour under conditions of a load of 1 kg and 200°C. For the test piece in the overlapped state under the above conditions, the tensile strength was measured using a universal testing machine (manufactured by Shimadzu Corporation) at room temperature in accordance with the tensile shear bond strength test method of JIS K6850, and the surface adhesiveness was evaluated according to the following criteria.

○: Tensile strength 0MPa

△: Tensile strength less than 1.0×10 ^-2 MPa

×: Tensile strength 1.0×10 ^-2 Mpa or more

<Form contamination (non-adhesion of coating and aluminum plate)>

The above test piece was cut into 2 cm wide pieces, and a separately prepared aluminum plate (2 cm wide) was overlapped on the 2 cm x 3 cm coating surface, and maintained for 1 hour under the conditions of a load of 1 kg and 200°C. After peeling off the overlapped test piece, the contamination level of the aluminum plate was visually evaluated using the following criteria.

○: No contamination

△: Slightly contaminated

×: Contamination on the entire surface

<My Scratch Flaw>

Using a HEIDON tester, the scratch-generating load of the coating of the test piece was measured and evaluated according to the following criteria.

○: 80g or more

△: 60 to 70g

×: 40 to 50g

<Paint Stability>

The non-adhesive treatment paint compositions obtained in the examples and comparative examples were stored at 25°C for 24 hours, then redispersed, filtered through a 100 mesh metal mesh, and the concentration of the filter residue was measured and evaluated according to the following criteria.

○: Less than 1 mass%

△: 2 to 4 mass%

×: 5 mass% or more

Claims (11)

Contains fluorine rubber, vulcanizing agent, solid lubricant, organic solvent and stabilizer,
The above solid lubricant comprises a solid lubricant (A) and a solid lubricant (B) different from the solid lubricant (A).
The above vulcanizing agent is a polyol vulcanizing agent.
A paint composition characterized in that the stabilizer comprises orthoesters and organic acids. A coating composition in claim 1, wherein the solid lubricant (A) is a fluororesin. A coating composition according to claim 1 or 2, wherein the solid lubricant (B) is at least one selected from the group consisting of graphite, molybdenum disulfide, tungsten disulfide, graphite fluoride, and boron nitride. A coating composition according to claim 1 or 2, wherein the mass ratio of the fluorine rubber and the solid lubricant (fluorine rubber/solid lubricant) is 20/80 to 80/20. A coating composition according to claim 1 or 2, wherein the mass ratio of the solid lubricant (A) and the solid lubricant (B) (solid lubricant (A)/solid lubricant (B)) is 50/50 to 90/10. delete A paint composition according to claim 1 or 2, which is a paint composition for non-adhesive treatment. A paint composition according to claim 1 or 2, which is a paint composition for non-adhesive treatment of an elastomer layer. Metal plate and,
An elastomer layer provided on one or both sides of the metal plate,
A coating film formed with a coating composition described in claim 1 or claim 2, provided on the elastomer layer
A painted article characterized by having a . A painted article in claim 9, wherein the elastomer layer is a fluorine rubber layer. A painted article, wherein the article is a fluorine rubber coat gasket material in accordance with claim 9.