JPWO2020171193A1 - Fluororubber paint composition and painted articles - Google Patents

Abstract

Provided is a coating composition which gives a coating film which is hard to be removed from a substrate and has a small compression set. Fluororubber, polyol-based vulcanizer, amino group-containing metal compound and organic solvent are included, and the polyol-based vulcanizer and the amino group-containing metal compound are added to 100 parts by mass of the fluororubber in a total of 0.1 to 4 A fluororubber coating composition comprising .99 parts by mass.

Description

The present disclosure relates to fluororubber coating compositions and coated articles.

Fluororubber is used not only for molded products but also for coatings due to its excellent heat resistance, oil resistance, solvent resistance, and chemical resistance. The latter includes, for example, woven fabrics, fibers, metals, and plastics. It is widely used as an industrial material by coating or impregnating rubber and various other substrates.

Patent Document 1 describes a fluororubber, a polyol-based vulcanizing agent, a coating material containing 15 parts by weight of an amino group-containing metal compound with respect to 100 parts by weight of the fluororubber, methyl isobutyl ketone and the like.

Patent Document 2 describes a paint containing a fluororubber, a polyol vulcanizer, a propylene glycol diacetate (thickener), a methyl isobutyl ketone (a good solvent), an isoparaffin solvent (a defoaming organic liquid), and the like. There is.

Japanese Unexamined Patent Publication No. 2002-338872 Japanese Unexamined Patent Publication No. 2006-070132

It is an object of the present disclosure to provide a coating composition which gives a coating film which is hard to be removed from a substrate and has a small compression set, and a coated article having such a coating film.

The present disclosure includes fluororubbers, polyol vulcanizers, amino group-containing metal compounds and organic solvents.
The present invention relates to a fluorine rubber coating composition, which comprises 0.1 to 4.99 parts by mass in total of the polyol-based vulcanizing agent and the amino group-containing metal compound with respect to 100 parts by mass of the fluorine rubber.

The mass ratio of the polyol vulcanizer to the amino group-containing metal compound is preferably 1.0: 0.1 to 1.0: 1.2.

It is preferable that the metal of the amino group-containing metal compound is at least one selected from the group consisting of Si, Al, Ti and Zr.

It is preferable that the amount of the polyol vulcanizer is 0.1 to 3 parts by mass and the amount of the amino group-containing metal compound is 0.1 to 2 parts by mass with respect to 100 parts by mass of the fluororubber.

The fluororubber coating composition preferably further contains a stabilizer.

The stabilizer is preferably an ortho ester compound.

The fluororubber coating composition preferably further contains a surface conditioner.

The fluororubber coating composition preferably further contains an antifoaming agent.

This disclosure describes a metal plate and
It also relates to a coated article characterized by having a coating film formed from the fluororubber coating composition provided on one side or both sides of the metal plate.

The coated article is preferably a fluororubber coated gasket material.

According to the present disclosure, it is possible to provide a coating composition that is hard to be removed from a substrate and gives a coating film having a small compression set, and a coated article having such a coating film.

Hereinafter, the present disclosure will be specifically described.
The present disclosure includes a fluororubber, a polyol-based vulcanizer, an amino group-containing metal compound and an organic solvent, and the polyol-based vulcanizer and the amino group-containing metal compound are 0 in total with respect to 100 parts by mass of the fluororubber. The present invention relates to a fluororubber coating composition containing 1 to 4.99 parts by mass.
Since the fluororubber coating composition of the present disclosure contains the above components, it is possible to provide a coating film which is less likely to be removed from the substrate (the coating film is less likely to settle) and has a small compression set. Therefore, when the above coating composition is applied to a sealing material, excellent sealing properties can be obtained.
The coating composition of the present disclosure is also excellent in coating stability.

Examples of the fluororubber include vinylidene fluoride [VdF] -based fluororubber, tetrafluoroethylene [TFE] / propylene [Pr] -based fluororubber, TFE / Pr / VdF-based fluororubber, and ethylene [Et] / hexafluoropropylene [HFP]. ] -Based fluororubber, Et / HFP / VdF-based fluororubber, Et / HFP / TFE-based fluororubber, fluorosilicone-based fluororubber, fluorophosphazen-based fluororubber, and the like. Of these, VdF-based fluororubber is preferable.
As the fluororubber, one kind or two or more kinds can be used.

Examples of the VdF-based fluororubber include VdF / HFP copolymer, VdF / TFE / HFP copolymer, VdF / chlorotrifluoroethylene [CTFE] copolymer, VdF / CTFE / TFE copolymer, and VdF / perfluoro. (Alkyl Vinyl Ether) [PAVE] Polymer, VdF / TFE / PAVE Polymer, VdF / HFP / PAVE Polymer, VdF / HFP / TFE / PAVE Polymer, VdF / TFE / Pr Polymer, VdF Examples thereof include a / Et / HFP copolymer and a VdF / a polymer of a fluorine-containing monomer represented by the formula (1).
Equation (1):
CH ₂ = CFRf (1)
(In the formula, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms).

As the polyol-based vulcanizing agent, a vulcanizing agent usually used for polyol vulcanizing fluororubber can be used. Examples of the polyol-based vulcanizing agent include compounds having at least two hydroxyl groups, particularly phenolic hydroxyl groups in the molecule and having vulcanizing performance, and this compound may be a polymer compound. ..

Examples of the polyol-based sulfide agent include phenol derivatives such as bisphenol A, bisphenol AF, and hydroquinone and salts thereof; polyhydroxy compounds having two or more enol-type hydroxyl groups such as phenol resin in the molecule and salts thereof. ; Formula: _{A compound represented by R f} ¹ (CH ₂ OH) ₂ (where R _f ¹ represents a perfluoroalkylpolyether group) is preferable.
As the above-mentioned polyol-based vulcanizing agent, in addition to the above, any commercially available polyol-based vulcanizing agent for fluororubber can be used.
As the above-mentioned polyol vulcanizing agent, one kind or two or more kinds can be used.

The polyol-based vulcanizing agent is preferably used in an amount of 0.1 to 3 parts by mass with respect to 100 parts by mass of the fluororubber. A more preferable lower limit is 0.5 parts by mass, and a more preferable upper limit is 2.5 parts by mass.

In the coating composition of the present disclosure, a vulcanization aid can also be used to promote vulcanization. Examples of the vulcanization aid include quaternary ammonium salts such as alkyl and aralkyl quaternary ammonium salts; quaternary 1,8-diaza-bicyclo [5.4.0] -7-undecenium salt; and quaternary amines. Quaternary phosphonium salt and the like can be mentioned.

When the vulcanization aid is used, the amount used is, for example, 0 to 10 parts by mass with respect to 100 parts by mass of the fluororubber. The preferred lower limit is 0.1 parts by mass, the more preferable lower limit is 0.3 parts by mass, and the preferred upper limit is 5 parts by mass.

As the amino group-containing metal compound, an amino group-containing metal compound containing at least one metal selected from the group consisting of Si, Al, Ti and Zr is preferable.
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, and N-β-aminoethyl. Examples thereof include −γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane, β-aminoethyl-β-aminoethyl-γ-aminopropyltrimethoxysilane.
The amino group-containing metal compound may be used alone or in combination of two or more.

The amino group-containing metal compound is preferably used in an amount of 0.1 to 2 parts by mass with respect to 100 parts by mass of the fluororubber. A more preferable lower limit is 0.5 parts by mass, and a more preferable upper limit is 1.5 parts by mass.

The coating composition of the present disclosure contains 0.1 to 4.99 parts by mass of the polyol vulcanizer and the amino group-containing metal compound in total with respect to 100 parts by mass of the fluororubber. When the total amount of the polyol vulcanizer and the amino group-containing metal compound is within the above range, a coating film that is less likely to be removed from the substrate and has a small compression set can be obtained. In addition, it has excellent paint stability.
The total amount of the polyol vulcanizer and the amino group-containing metal compound is preferably 1 part by mass or more, more preferably 2 parts by mass or more, with respect to 100 parts by mass of the fluororubber. It is more preferably 2 parts by mass or more. Further, it is preferably 4.5 parts by mass or less, and more preferably 4 parts by mass or less.

The mass ratio of the polyol vulcanizer to the amino group-containing metal compound (polyol vulcanizer: amino group-containing metal compound) shall be 1.0: 0.1 to 1.0: 1.2. Is preferable. When the mass ratio is within the above range, a coating film that is less likely to be removed from the substrate and has a smaller permanent compression strain can be obtained.
The mass ratio is more preferably 1.0: 0.2 to 1.0: 1.0, and even more preferably 1.0: 0.5 to 1.0: 0.9.

The coating composition of the present disclosure contains an organic solvent. The coating composition of the present disclosure may be a solvent-based coating material.
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, and 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 kind of the above organic solvent, or may use two or more kinds of organic solvents. The blending amount of the organic solvent can be appropriately adjusted according to the type of fluororubber blended in the coating composition.

The coating composition of the present disclosure preferably further contains a stabilizer. This makes the paint more stable.
Examples of the stabilizer include ortho-grate, ortho-carbonate, cyclic ortho-ester, lactone acetal, ortho-geic acid trimethyl ester, ortho-girate triethyl ester, ortho-acetic acid trimethyl ester, ortho-acetic acid triethyl ester, ortho-carbonate trimethyl ester, ortho-carbonate triethyl ester. , Ortho ester compounds such as orthocarbonate tetramethyl ester and orthocarbonate tetraethyl ester; organic acids such as monocarboxylic acid (artic acid, acetic acid, propionic acid, etc.) and dicarboxylic acid (oxalic acid, malonic acid, succinic acid, etc.). Is done. Of these, the ortho ester-based compound is preferable, and the orthoacetate-based compound is more preferable.
The coating composition of the present disclosure may use only one kind of the above stabilizer, or may use two or more kinds of stabilizers.

The stabilizer is preferably used in an amount of 1 to 8 parts by mass with respect to 100 parts by mass of the fluororubber. A more preferable lower limit is 2 parts by mass, and a more preferable upper limit is 6 parts by mass.

The coating composition of the present disclosure preferably further contains a surface conditioner.
Examples of the surface conditioner include siloxane compounds, acrylic copolymers, and methacrylic copolymers. Of these, an acrylic copolymer is preferable.

The surface conditioner is preferably used in an amount of 0.01 to 1 part by mass with respect to 100 parts by mass of the fluororubber. A more preferable lower limit is 0.02 parts by mass, and a more preferable upper limit is 0.5 parts by mass.

The coating composition of the present disclosure preferably further contains an antifoaming agent.
Examples of the defoaming agent include silicon-based defoaming agents and polymer-based defoaming agents. Of these, a polymer-based defoaming agent is preferable.

The defoaming agent is preferably used in an amount of 0.05 to 4 parts by mass with respect to 100 parts by mass of the fluororubber. A more preferable lower limit is 0.1 parts by mass, a more preferable upper limit is 3 parts by mass, and a further preferable upper limit is 2 parts by mass.

The coating composition of the present disclosure preferably contains both the surface conditioner and the antifoaming agent. Thereby, even if the addition amount of these components is small, excellent defoaming property can be realized. Further, it is possible to obtain a coating film having excellent interlayer adhesion (particularly, adhesion with the upper layer).
The mass ratio (surface adjusting agent / defoaming agent) of the surface adjusting agent and the defoaming agent is preferably 1/20 to 1/50, and more preferably 1/30 to 1/40.

In addition to the above components, various additives such as fillers and colorants can be added to the coating composition of the present disclosure.
Examples of the filler include carbon black, white carbon, calcium carbonate, barium sulfate, talc, calcium silicate and the like.
Examples of the colorant include inorganic pigments and composite oxide pigments.

A coating film can be formed by applying the coating composition of the present disclosure to a substrate and drying it. The coating composition of the present disclosure may be applied directly to the substrate or may be applied via another layer such as a primer.

The coating composition can be applied by a known coating method such as brush coating, spray coating, dip coating, flow coating, dispenser coating, screen coating and the like.

After the above coating and drying, curing may be performed if necessary. When other layers are provided, the above-mentioned curing may be performed for each layer, or may be performed for a plurality of layers at once. Further, the curing may be performed at the same time as the drying.
The drying and curing conditions can be appropriately set according to the type and the like of the coating composition of the present disclosure.

As the base material to which the coating composition of the present disclosure can be applied, a base material made of metal, concrete, plastic, stone, wood, paper or the like can be used. Of these, a base material made of metal is preferable.

Examples of the metal include iron; stainless steel; aluminum; copper; brass; titanium; zinc-plated, aluminum-plated plated steel plate and the like. Of these, stainless steel is preferable.

The present disclosure also relates to a coated article comprising a metal plate and a coating film formed from the fluororubber coating composition of the present disclosure provided on one or both sides of the metal plate.
Since the coated article of the present disclosure has a coating film formed from the coating composition of the present disclosure, the coating film is less likely to be removed from the base material (the coating film is less likely to settle), and the compression set is small. Therefore, when the above-mentioned coated article is applied to a sealing material, excellent sealing properties can be obtained.

As the metal plate, a plate made of a metal exemplified as a base material on which the coating composition of the present disclosure can be applied can be used.

The coating film formed from the coating composition of the present disclosure is provided on one side or both sides of the metal plate. The coating film may be provided directly on the metal plate or may be provided via another layer such as a primer layer.

The thickness of the coating film is preferably 5 to 50 μm, more preferably 10 to 30 μm.

Another layer may be further provided on the coating film.

The coated article of the present disclosure can be produced, for example, by applying the coating composition of the present disclosure on the metal plate and drying it.
After the coating composition is applied and dried, it may be cured if necessary. When other layers are provided, the above-mentioned curing may be performed for each layer, or may be performed for a plurality of layers at once. Further, the curing may be performed at the same time as the drying.
The drying and curing conditions can be appropriately set according to the type and the like of the coating composition of the present disclosure.

The coating composition and the coated article of the present disclosure can be used in a field where a coating that is hard to be removed from the substrate and has a small compression set is required. For example, various seat belts; O-rings, diaphragms, etc. Sealing materials such as valve seals, gaskets for chemical plants, engine gaskets; Fluid transport members such as chemicals such as chemical resistant tubes, fuel hoses, and fittings; Rolls for OA equipment such as copiers, printers, and facsimiles (for example, fixing rolls) , Crimping roll) or a conveyor belt, etc., and above all, it can be preferably used for a gasket. It is one of the preferred embodiments that the coated article of the present disclosure is a fluororubber coated gasket material.

Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

<Preparation of fluororubber paint composition>
Example 1
5 parts by mass of carbon black and an acid receiving agent with respect to 100 parts by mass of the solid content of the elastomer composed of vinylidene fluoride / hexafluoropropylene copolymer (vinylidene fluoride: hexafluoropropylene = 78: 22 in molar ratio) as fluororubber. 5 parts by mass were kneaded with an open roll to obtain a compound. This compound was mixed with a mixed solvent composed of 240 parts by mass of diisobutyl ketone and 70 parts by mass of isophorone as an organic solvent to obtain a compound solution.
On the other hand, 2 parts by mass of the polyol vulcanizing agent and 0.5 part by mass of the vulcanization aid are dissolved in 10 parts by mass of ethanol, and 2 parts by mass of the orthoacetate ester compound and 2 parts by mass of the organic acid are used as stabilizers therein. Was added. This solution is mixed with the previously prepared compound solution with a disper, and further, 0.05 parts by mass of an acrylic copolymer as a surface conditioner, 1.8 parts by mass of a polymer-based defoaming agent as a defoaming agent, and amino. 1.2 parts by mass of the group-containing metal compound was mixed to obtain a fluororubber coating composition.

Examples 2-6
A fluororubber coating composition was obtained in the same manner as in Example 1 except that the blending amounts of the surface conditioner and the defoaming agent (or the defoaming organic liquid) were changed as shown in Table 2.
As the defoaming organic liquid, an isoparaffin solvent having a surface tension of 0.026 Nm- ¹ or less was used.

Example 7
A fluororubber coating composition was obtained in the same manner as in Example 1 except that the orthoacetate ester compound was not blended as a stabilizer.

Examples 8 and 9
A fluororubber coating composition was obtained in the same manner as in Example 1 except that the blending amount of the amino group-containing metal compound was changed as shown in Table 1.

Comparative Examples 1 and 2
A fluororubber coating composition was obtained in the same manner as in Example 1 except that the blending amounts of the polyol vulcanizing agent and the amino group-containing metal compound were changed as shown in Table 1.

Comparative Example 3
Fluororesin is the same as in Example 1 except that the blending amounts of the polyol vulcanizing agent and the amino group-containing metal compound are changed as shown in Table 1 and the orthoacetate ester compound is not blended as a stabilizer. A rubber coating composition was obtained.

Comparative Example 4
A fluororubber coating composition was obtained in the same manner as in Comparative Example 1 except that the orthoacetate ester compound was not blended as a stabilizer.

<Preparation of coating film>
25 g of the above paint composition was placed in a fluorine-coated hand-sized tray, spread over the entire surface, and then allowed to stand at room temperature for 3 days. Next, it was dried at 100 ° C. for 24 hours and then calcined at 200 ° C. for 60 minutes. After firing, the film was taken out and the film thickness was measured to be about 300 μm.

<Manufacturing of painted plates (painted articles)>
The above coating composition was applied to a SUS301 plate that had been previously washed with acetone with a 16-mil apricketer. After pre-drying, it was dried at 80 to 100 ° C. for 30 minutes and then baked at 200 ° C. for 30 minutes.

<Coating film settling (missing)>
The coated plate was sandwiched between the jigs for measuring compression permanent strain without using a spacer and held at 200 ° C. for 5 hours, and then the presence or absence of missing coating film edges was visually observed and evaluated. Those with no protrusion or omission of the coating film were marked with ◯, those with no omission of the coating film but with protrusion were marked with Δ, and those with the omission of the coating film were marked with x. The results are shown in Table 1.

<Sealability (compressive permanent strain): Compliant with JIS K6262-5>
The coating films were superposed so as to have a thickness of about 10 mm, and the thickness was measured with a dial gauge. Next, the sample was placed in a furnace under 25% compression and pressurization at a temperature of 175 ° C. for 72 hours, then taken out of the furnace, allowed to cool at room temperature for 30 minutes, and the thickness was measured with a dial gauge and calculated according to the following formula. The results are shown in Table 1.

Compression set (rate) = 100 × (t ₀ −t ₁ ) / (t ₀ −t ₂ )
However, t ₀ : thickness before compression (mm)
t ₁ : Thickness after compression (mm)
t ₂ : Spacer thickness (mm)
Those having a compression set of 50% or less were evaluated as ◯, those having a compression set of 51% to 89% were evaluated as Δ, and those having a compression set of 90% or more were evaluated as x.

<Defoaming property (painting property)>
The fluororubber coating composition was sufficiently stirred and then applied onto a SUS301 plate previously washed with acetone so that the thickness of the coating film after firing was 25 μm by a screen printing method. In the first application, there are many bubbles formed by the air in the mesh of the screen moving into the coating film, so the application was performed 5 times, and in each of the 2nd and subsequent 4 times, the stopwatch was put on immediately after the application was completed. The time from the start to the complete disappearance of bubbles from the coating film was measured, and the average value of 4 times was taken as the defoaming time. The screen printing machine used for coating was a commercially available manual printing method, and a screen with a 70 mesh ring-shaped pattern generally available was used. The results are shown in Table 2.

<Interlayer adhesion (against topcoat layer)>
A fluororubber paint (VdF / HFP copolymer methyl ethyl ketone [MEK] solution) was dip-coated on the coating film of the coating plate obtained above, dried at 100 ° C. for 30 minutes, and then dried at 200 ° C. at 200 ° C. A test piece was obtained by firing for 30 minutes.
In accordance with JIS K5400, the cellophane tape peeling on the coating film surface of the test piece was repeated 10 times, and the number of cells of the coating film remaining without peeling (out of 100 cells) was determined.
The results are shown in Table 2.

<Paint stability (pot life, physical characteristics of coating film after storage)>
The fluororubber coating compositions obtained in Examples and Comparative Examples were stored at 25 ° C. for the time shown in Table 3, and then the coating viscosity was measured using a B-type viscometer.
A coated plate was prepared in the same manner as above using the fluororubber coating composition stored at 25 ° C. for 24 hours, and the physical properties of the coating film (coating film settling, sealing property) were evaluated.
The results are shown in Table 3.

Claims (10)

Includes fluororubber, polyol vulcanizer, amino group-containing metal compound and organic solvent,
A fluorine rubber coating composition comprising the polyol vulcanizing agent and the amino group-containing metal compound in a total amount of 0.1 to 4.99 parts by mass with respect to 100 parts by mass of the fluorine rubber. The fluororubber coating composition according to claim 1, wherein the mass ratio of the polyol-based vulcanizing agent to the amino group-containing metal compound is 1.0: 0.1 to 1.0: 1.2. The fluororubber coating composition according to claim 1 or 2, wherein the metal of the amino group-containing metal compound is at least one selected from the group consisting of Si, Al, Ti and Zr. The invention according to any one of claims 1 to 3, wherein the polyol-based vulcanizing agent is 0.1 to 3 parts by mass and the amino group-containing metal compound is 0.1 to 2 parts by mass with respect to 100 parts by mass of the fluororubber. Fluoro rubber paint composition. The fluororubber coating composition according to any one of claims 1 to 4, further comprising a stabilizer. The fluororubber coating composition according to claim 5, wherein the stabilizer is an ortho ester compound. The fluororubber coating composition according to any one of claims 1 to 6, further comprising a surface conditioner. The fluororubber coating composition according to any one of claims 1 to 7, further comprising an antifoaming agent. With a metal plate
A coated article comprising a coating film formed from the fluororubber coating composition according to any one of claims 1 to 8, which is provided on one side or both sides of the metal plate. The painted article according to claim 9, which is a fluororubber-coated gasket material.