WO2007119450A1

WO2007119450A1 - Aqueous dispersion composition for primer

Info

Publication number: WO2007119450A1
Application number: PCT/JP2007/055674
Authority: WO
Inventors: Yoshihiro Soda; Hiroshi Torii
Original assignee: Daikin Industries, Ltd.
Priority date: 2006-03-30
Filing date: 2007-03-20
Publication date: 2007-10-25
Also published as: JP2007269878A; JP4853081B2; CN101405358B; CN101405358A

Abstract

Disclosed is an aqueous dispersion composition which enables to form a primer layer that is excellent in interlayer adhesion with a top coat layer containing a fluororesin and capable of improving hardness and wear resistance of a coating film as a whole. Also disclosed is a coating film structure using such an aqueous dispersion composition. Specifically disclosed is an aqueous dispersion composition for primers for fluororesin coating film layers, which contains (A) a water-soluble, curable polyamideimide and/or polyimide binder polymer, (B) ceramic spherical particles, (C) modified PTFE particles and (D) an aqueous medium. This aqueous dispersion composition for primers is characterized in that the modified PTFE particles (C) have a melt creep viscosity at 380˚C within the range from 2 Χ 109 to 1 Χ 1011 Pa·s, and a standard relative density of not more than 2.170. A primer layer is formed by using such an aqueous dispersion composition for primers, and a top coat layer containing a fluororesin is formed thereon.

Description

Aqueous dispersion composition for primer

Technical field

TECHNICAL FIELD [0001] The present invention relates to an aqueous dispersion composition for a primer, particularly an aqueous dispersion composition for a primer having a topcoat layer containing a fluorine resin, and has excellent interlayer adhesion with the topcoat layer, and the coating film as a whole. The present invention relates to an aqueous dispersion composition capable of forming a primer layer capable of improving the hardness and abrasion resistance of the composition.

Background art

[0002] Fluorine resin has been widely used as a coating material for metal substrates of cooking appliances and home appliances, utilizing the excellent non-adhesiveness, antifouling properties, and heat resistance of fluorine resin.

[0003] However, since fluorine resin is inferior in adhesion to metal, in many cases, a primer layer having excellent adhesion to a metal substrate is used as an undercoat layer for the top coat of fluorine resin. On the surface. In such a primer composition, an organic solvent-soluble thermosetting heat-resistant binder is used to increase the coating film hardness, and one of them is a water-soluble and thermosetting binder polymer. Polyamideimide or polyimide may be used. However, it is known that a primer obtained using a water-soluble binder polymer contains a sufficient amount of ceramic spherical particles to improve the film hardness in a water-soluble binder polymer whose film hardness is difficult to increase. . However, if a sufficient amount of ceramic spherical particles is added to improve the coating film hardness, the interlaminar adhesion between the primer layer and the top coat layer thereon is lowered.

[0004] In Japanese Patent Publication No. 7-506514, therefore, water-soluble and curable polyamideimide, aluminum oxide and polytetrafluoroethylene (PTFE), and tetrafluoroethylene monohexaflux are used. A copolymer selected from fluoropropylene copolymer (FEP) and tetrafluoroethylene perfluoro (alkyl vinyl ether) copolymer (PFA) is mixed at a specific ratio to form a primer layer, which is the same as above. An intermediate layer in which a copolymer selected from acid aluminum and PTFE and a copolymer selected from FEP and PFA is mixed at a specific ratio is interposed between the top coat and the top coat. However, a three-layer structure is naturally a coating formation In addition, there is a new problem of increased adhesion and poor interlayer adhesion due to increased costs and intermediate layer thickness.

[0005] To improve this point, by using PTFE particles or modified PTFE particles to be added that have a specific melt viscosity, a primer layer and a fluororesin coating layer (without using FEP or PFA) ( It has been proposed to improve the interlayer adhesion with the top coat (Japanese Patent Publication No. 2001-519830). However, the tetrafluoroethylene (TFE) homopolymer PTFE particles used have a melt creep viscosity of 3 X 10 ^{8 to} 3 X 10 ⁹ Pa's and a standard specific gravity (a factor that is a measure of molecular weight). PTFE particles with a standard specific gravity (molecular weight) of this level are still insufficient, and there is sufficient molecular weight between the primer and the top coat. It is difficult to obtain interlayer adhesion. In addition, modified PTFE particles (PTFE copolymerized with a small amount of a modifying monomer) particles have a standard specific gravity of 2.165 or more and are swept toward the high molecular weight side, but the melt creep viscosity is 1 X 10 ⁷ ~ It is insufficient in terms of peel strength in a high temperature environment as low as 1 X 10 ⁹ Pa's. Disclosure of the invention

[0006] The present invention provides an aqueous dispersion assembly capable of forming a primer layer that is excellent in interlayer adhesion with a topcoat layer containing fluorine resin and that can improve the hardness and wear resistance of the entire coating film. The purpose is to provide a composition.

That is, the present invention relates to (A) a water-soluble and curable polyamideimide-based and Z- or polyimide-based binder polymer, (B) ceramic spherical particles, (C) modified polytetrafluoroethylene particles and ( D) In the aqueous dispersion composition for a primer of the fluororesin coating layer containing an aqueous medium, the modified polytetrafluoroethylene particles (C) have a melt creep viscosity at 380 ° C. of 2 × 10 ⁹ to 1 The present invention relates to an aqueous dispersion composition for a primer characterized in that it is a modified polytetrafluoroethylene particle having a standard specific gravity of 2.170 or less in the range of X 10 ^u Pa's.

[0008] In addition, the present invention provides a layer structure comprising a primer layer obtained by applying this aqueous dispersion composition for a primer to a substrate, and a fluorine resin top coat layer provided immediately above the primer layer. Further, the present invention relates to a coating film structure to be included, and also to a coated article having this coating film structure on the surface. BEST MODE FOR CARRYING OUT THE INVENTION

[0009] The aqueous dispersion composition for a primer of the present invention comprises (A) a water-soluble and curable polyamideimide-based and Z- or polyimide-based binder polymer, (B) ceramic spherical particles, and (C) a modified polytetrafluorocarbon. In an aqueous dispersion composition for a fluororesin coating layer containing ethylene particles and (D) an aqueous medium, specific modified PTFE particles (C) are used as the modified polytetrafluoroethylene particles (C). The use solves the above problems. Therefore, conventionally known components can be used as components other than the specific modified PTFE particles (C). However, there are preferable combinations in relation to specific modified PTFE particles (C), which will be described later.

[0010] Hereinafter, each component will be described.

[0011] (A) Water-soluble and curable polyamideimide-based and Z- or polyimide-based binder polymer Water-soluble ¾re so that polyamideimide-based and Z- or polyimide-based binder polymer (hereinafter sometimes simply referred to as "binder polymer") The ceramic spherical particles (B) and PTFE particles (C) can be uniformly dispersed as a solid-liquid dispersion.

[0012] Specific examples of the polyamideimide polymer include HPC-1000-28 (acid value 42mgKOH / g) manufactured by Hitachi Chemical Co., Ltd., JP 7-506514, JP 2001 2001— Those described in Japanese Patent No. 519830. Polyamideimide binder The acid value of the polymer is preferably in the range of 40 to 90 mgKOHZg, and more preferably 42 to 8 OmgKOHZg.

[0013] Of these, polyamideimide-based polymer strength is particularly preferable.

[0014] (B) Ceramic spherical particles

Conventionally known ceramic spherical particles can be used. For example, the power of acid aluminum particles, zirconium oxide particles, silicon nitride, cobalt aluminate, aluminum borate, silicon carbide, acid value titanium, silica, apatite, aluminum hydroxide, talc, ultramarine Examples of such particles include high-hardness ceramic spherical particles described in JP 7-506514 A, JP 2001-519830 A, and the like, such as calcium metasilicate and potassium titanate. Of these, it is cheap and easy to obtain despite its high hardness, food When used for containers and the like, particularly preferred are aluminum oxide particles, ultramarine particles, glass particles, and titanium oxide particles, which have good safety. The hardness of the ceramic spherical particles is preferably 6 or more, particularly 8 or more in terms of Mohs hardness.

A spherical shape is adopted because the shape close to a sphere can be uniformly dispersed. Therefore, fibrous materials are not suitable. The average particle size is not particularly limited, but those exceeding 10 m are preferable because the coating surface becomes rough.

[0016] (C) Modified PTFE particles

The present invention relates to PTFE particles having (i) a melt creep viscosity at 380 ° C. in the range of 2 × 10 ⁹ to ¹ × 10 ¹ ipa's and (ii) a standard specific gravity of 2.170 or less. It is characterized by the use of PTFE particles.

[0017] When the melt creep viscosity (i) is within this range, the modified PTFE particles have a low melt creep viscosity instead of a high molecular weight, and thus the adhesion of the modified PTFE particles is improved, so that the interlayer adhesion is improved. . Preferred melt creep viscosities are 5 × 10 ⁹ Pa ′s or more and 8 × 10 ⁹ Pa ′s or more. When the melt creep viscosity is low, the surface of the topcoat layer tends to be scratched.On the other hand, when the melt creep viscosity is high, the melt adhesion is lowered and the interlayer adhesion between the topcoat layer and the primer layer is reduced, particularly at high temperatures. Works in a direction that impairs interlayer adhesion. The preferred upper limit is 5. Ο Χ 1Ο ¹⁰ Ρ a 's, or even 1. OX lC ^ Pa' s.

[0018] The standard specific gravity of the modified PTFE particles (C) must be 2.170 or less! /. The molecular weight of PTFE is difficult to measure directly because the melt viscosity of PTFE is extremely high, and the standard specific gravity is used as one means of evaluating the molecular weight. The relationship between the standard specific gravity and the molecular weight is a linear correlation in which the molecular weight decreases as the standard specific gravity increases.

[0019] When the standard specific gravity exceeds 2.170 (molecular weight decreases), interlayer adhesion decreases. The lower limit of the standard specific gravity (the upper limit of the molecular weight) is usually about 2.146, but it is 2.146, preferably 2.165, due to the balance between fusion and durability.

[0020] In the present invention, it is important that the melt creep viscosity and the standard specific gravity are both in the above ranges. If either one is out of the range, the effect of improving the interlayer adhesion becomes insufficient, and the Abrasion resistance does not reach the desired level of scratch resistance. [0021] The modified PTFE particles (C) may be modified PTFE in which PTFE is modified with another monomer V. It is difficult to obtain a balance between melt creep viscosity and standard specific gravity with PTFE particles, which are homopolymers of TFE, but it is easy to adjust the balance between melt creep viscosity (i) and standard specific gravity (ii) by modification. Become.

[0022] Monomers used for modification include, for example, black trifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoro (alkyl butyl ether) having 1 to 3 carbon atoms in the alkyl group ( PAVE) and the like, and HFP and PAVE are also particularly preferred for their excellent heat resistance. The amount of modification may be appropriately selected according to the target melt creep viscosity and standard specific gravity according to the monomer used for modification, and is usually 0.01% by mass or more, preferably 0.10% by mass or more. Adjust it. The upper limit same viewpoint force even 0.22% by mass, preferably 0.20 mass ^_0/0.

[0023] The average particle size of the modified PTFE particles (C) is 0.20 μm or more, and the point power with good film-forming property, adhesion to the substrate and melt adhesion with the top coat is also preferred. Furthermore, the thing of 0.25 micrometer or more is preferable. The upper limit is preferably 10 m from the viewpoint of not roughening the coating surface. Modified PTFE particles having such a particle size can be obtained in the form of a dispersion by emulsion polymerization of TFE and a modifying monomer.

[0024] (D) Aqueous medium

Water is sufficient and preferred. A surfactant described later may be added to this aqueous medium, and a water-soluble organic solvent may be used in combination as necessary.

[0025] Next, the blending ratio of the components (A) to (C) will be described.

[0026] First, the mass ratio (C) / (A) of water-soluble and curable polyamideimide-based and Z- or polyimide-based noinder polymer (A) to modified PTFE particles (C) is in the range of 60Z40-80Z20. It is also preferable to have a point force that provides good adhesion to the substrate and adhesion to the topcoat layer. Furthermore, (C) Z (A) is preferably 70-30 to 80-20, particularly 70 30 to 7525.

[0027] ceramic spherical particles (beta) is ceramic spherical particles of the type and hardness such as by the amount force can be adjusted normally used in 30-250 capacitance range ^_0/0 of Noin Zehnder polymer (Alpha) However, a point force capable of maintaining high hardness is also preferable. Especially for acid-aluminum particles In this case, when it is within this range, cracks are not generated in the DuPont impact test, and the corrosion resistance is also good. A particularly preferred range from 50 to 200 volume ^_0/0, even at 100-175% by volume.

[0028] The aqueous medium (D) is added in an arbitrary amount in consideration of coatability. Usually, the amount that makes the viscosity of the aqueous dispersion composition for primer in the range of 100 to 350 Pa · s is preferable.

[0029] The primer-based aqueous dispersion composition of the present invention may contain other components as needed. These representative examples will be described below.

[0030] (E) Nonionic surfactant

It is added for the purpose of improving the dispersion stability of the modified PTFE particles. Other surfactants such as cationic surfactants, cationic surfactants and amphoteric surfactants are difficult to thermally decompose, and when metal ions are contained, they tend to lower the corrosion resistance.

[0031] Preferable nonionic surfactants are, for example, those that do not contain or release the alkyl phenol units that are environmentally friendly. Specific examples include nonionic surfactants described in International Publication No. 03 Z106556 pamphlet and the like, and among these, they are particularly susceptible to thermal decomposition! Agents, and even polyoxyethylene isotridecyl ether, are preferred.

[0032] The addition amount varies depending on the addition amount of the modified PTFE particles, etc. Usually in the range of 5.0 to 7.0 parts by weight, particularly 5.5 to 6.5 parts by weight with respect to 100 parts by weight of the modified PTFE particles. It is preferable to select.

[0033] (F) Other fluorine-based resin particles

In addition to the modified PTFE particles (C), other fluororesin particles or TFE homopolymer (PTFE) particles may be added for the purpose of improving corrosion resistance.

[0034] Examples of other fluorinated resin particles include PFA particles, FEP particles, or one or more of PTFE particles other than the modified PTFE particles (C).

[0035] The average particle size of the other fluorinated resin particles (F) is in the range of 0.15 to 0.60 m. Strength The film forming property is not lowered and the processed coating surface is not roughened. Further, it is preferable to have a force of 0.16 to 0.55 m. The amount of the applied force may be selected within the range that achieves the purpose of the above-mentioned additive, but if the amount is too large, the interlayer adhesion is impaired. Particles (C) It is preferably 0 to 30 parts by mass, more preferably 20 parts by mass or less, per 100 parts by mass.

[0036] (G) Pigment (excluding ceramic spherical particles (B))

Ordinary inorganic pigments such as carbon black, titanium oxide, and bengara, and inorganic pigments such as My strength coated with titanium oxide and bengara may be added.

[0037] (H) Other additives

You may add a thickener, a leveling agent, a ultraviolet absorber, an antifoamer, etc.

[0038] The aqueous dispersion composition for a primer of the present invention can be produced by mixing each component by a usual method. However, it is preferable that the binder polymer (A) is preliminarily dissolved in the aqueous medium (D) to form an aqueous solution, and a solid component is appropriately added to this and stirred and mixed in order to obtain a uniform dispersed state.ヽ.

[0039] The primer-based aqueous dispersion composition of the present invention is applied to a substrate by a usual method and dried and cured to form a primer layer. The coating method is not particularly limited, and a roll coating method, a spray method, a spin coating method and the like are employed. Drying and curing conditions are infrared drying, hot air drying, etc. A primer layer with the required hardness is usually obtained at 80 to 200 ° C for 3 to 20 hours.

[0040] The substrate is not particularly limited. For example, various metals, enamel, glass, and various ceramics can be used, and the surface is preferably roughened by a sandblasting method in order to improve adhesion. However, various metals can be sprayed onto the substrate surface.

[0041] As the fluororesin constituting the fluororesin coating layer (topcoat) provided immediately above the primer layer, the fluororesin containing fluorephine as a structural unit has good non-adhesiveness. Is preferable.

[0042] Fluoroolefins such as tetrafluoroethylene (TFE), perfluoro (alkyl ether) (PAVE), hexafluoropropylene (HFP), black trifluoroethylene (CTFE), etc. Perhaloolefins; vinylidene fluoride (VdF) and the like. Perhaloolefins, particularly perfluoroolefin homopolymers or copolymers, are particularly preferred because of their excellent non-adhesiveness. Better ,.

[0043] Specific examples include modified PTFE, PFA, and FEP. Of these, high molecular weight Low melt creep viscosity, point power modified PTFE is preferred because melt creep viscosity is relatively low V, PFA is also preferred! The modified PTFE for the topcoat may be the same as or different from the modified PTFE for the primer in terms of properties, modification monomer, and modification amount. For example, the comonomers for modification can be those described for the modified PTFE particles (C), and the modification amount is usually in the range of 0.18 to 0.22 mass%.

[0044] Further, specific modified PTFE particles to be blended in the primer composition of the present invention may be added to the topcoat layer. The presence of the modified PTFE particles also in the topcoat layer further improves the interlayer adhesion with the primer layer. The amount to be blended is preferably 50% by mass or more of the total amount of the top coat layer. The entire topcoat layer may be composed of modified PTFE. If necessary, PFA may be mixed and used.

[0045] Thus, in the present invention, a two-layer coating film structure of the primer layer of the present invention and a topcoat layer containing fluorine resin can be formed. Of course, if necessary, a multi-layer structure of three or more layers may be used. For example, a primer layer + an intermediate layer + a top coat layer (fluorine resin) can be exemplified. However, since the number of formation processes increases and the number of layer interfaces increases (there is a risk of peeling when there are many pigments in the intermediate layer), the intermediate layer is coated with a normal colored top coat and the pigment is added to the finish. It is desirable to provide it when there is a request for a specific application or use environment, such as when applying a tally layer or metallic layer.

The intermediate layer may be formed of, for example, a composition obtained by arbitrarily mixing the primer composition and the topcoat composition or a colored topcoat composition.

[0047] In the case of a two-layer coating film structure, the thickness of the primer layer is preferably 5 to 15 m, and the thickness of the topcoat layer is preferably 20 to 30 μm.

[0048] In the case of a coating film structure of 3 layers or more, the thickness of the primer layer is preferably 5 to 15 m, the thickness of the intermediate layer is 5 to 15 m, and the other layers are articles for forming a coating film. Select the appropriate one according to the required characteristics!

[0049] The primer layer of the present invention has high hardness and high adhesiveness to fluorine resin. Therefore, even if the coating film has a two-layer structure as described above, the excellent effect that the balance of hardness and adhesion can be obtained to the same extent as the three-layer structure can be exhibited. In addition, the wear resistance of the coating film as a whole is improved regardless of the material of the topcoat layer. This is a primer layer and fluorine resin top coat It is considered that wear due to delamination (abrasion delamination) is reduced by improving interlayer adhesion with the layer. When using high molecular weight, low melt creep viscosity fluorocarbon resin for the topcoat, the topcoat has good wear resistance as well as excellent interlayer adhesion. Heat resistance can be further improved. In addition, when used together with low chemical permeability fluorine resin (eg FEP and PFA), delamination and discoloration due to chemical (solvent) penetration can be further suppressed.

[0050] The coating film structure of the present invention having the above properties and effects is advantageous, for example, for coating metal utensils, particularly frying pans. This composition is suitable for coating other articles that require corrosion resistance. Can also be used. Other articles include, for example, bearings, valves, electric wires, metal foil, boilers, pipes, ship bottoms, oven linings, iron bottom plates, baking molds, rice cookers, grill pans, electric pots, various rolls of OA equipment, ice trays, Snow shovels, plows, chutes, conveyors, rolls, dies, various tools (dies, saws, files, drills, etc.), knives, scissors, hoppers, other industrial containers (especially for the semiconductor industry) and vertical molds It is done.

[0051] Next, particularly preferred embodiments of combinations of components in relation to coated articles (uses and applications) will be exemplified, but the present invention is not limited to these embodiments.

[0052] (Embodiment)

(A) Binder polymer:

Polyamideimide with an acid value of 40-90mgKOHZg. Used in the form of an aqueous dispersion.

(B) Ceramic spherical particles:

Acid-aluminum spherical particles with a Mohs hardness of 6 or more, composite oxide spherical particles, aluminum borate spherical particles, etc. Average particle size 0.4-2.

(C) Modified PTFE particles:

Modified PTFE particles with a melt creep viscosity of 2 X 10 ⁹ to 1 X 10 ^U Pa's and a standard specific gravity of 2. 170 or less. Used in the form of an aqueous dispersion.

(D) Aqueous medium:

water

(E) Nonionic surfactant: ヽ Nonionic surfactant without phenol structure

(F) Other fluorine resin particles:

FEP particles

(Combination ratio) (“parts by mass”, the same applies hereinafter)

(B) 170-352 parts, (C) 198-299 parts,) 7-11 parts, (F) 35-53 parts, (D) appropriate amount for 100 parts of component (A)

[0053] (Coated article)

Cooking utensils such as frying pans, hot plates, grilled meat plates, range tables, baking molds, rice cookers and grill pans;

Example

Next, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to such examples.

[0055] First, methods for measuring physical properties and effects employed in this specification will be described together.

[0056] (1) Melt creep viscosity at 380 ° C

Measuring method: Method described in JP-A-64-1711

[0057] (2) Standard specific gravity

Measuring method: Method described in JP-A-64-1711

[0058] (3) Acid value

Measurement method: TTM6540

[0059] (4) Average particle size

Measuring device: Laser diffraction scattering method

[0060] (5) Adhesion (cross cut test)

Measurement method: JIS K5600

[0061] (6) Substrate peel test (room temperature, 200 ° C)

Measurement method: Measured according to JIS K5600. In the case of 200 ° C, install a heater in the device. Measuring device: Pencil hardness tester with hot stage (Installed on Yasuda Seiki Seisakusho Co., Ltd. Pencil hardness tester with temperature adjustable stage)

Evaluation method: Indicates the pencil hardness used when the coating film peels from the substrate. High pencil hardness Indeed, the substrate adhesion is strong.

[0062] (7) Delamination test (room temperature, 200 ° C)

Measuring method: Same as base material peel test (6).

Measuring device: Pencil hardness tester with heater (Pencil hardness tester manufactured by Yasuda Seiki Seisakusho Co., Ltd. has a temperature adjustable stage)

Evaluation method: Indicates the pencil hardness used when the top coat peels from the primer. The higher the pencil hardness, the stronger the substrate adhesion.

[0063] (8) Impact resistance (DuPont impact)

Measurement method: JIS K5600, load 0.5kg is dropped from the height of lm.

Measuring device: DuPont drop impact tester

[0064] The components used in the examples and comparative examples are as follows.

[0065] (A) Water-soluble and curable polyamideimide and Z or polyimide binder polymer

A1: Toluon AI-10 (acid value 80mgKOH / g) from Solvay, USA neutralized with ammine (10%)

A2: HPC manufactured by Hitachi Chemical Co., Ltd. 1000-28 (acid value 42mgKOH / g, 28% aqueous solution)

[0066] (B) Ceramic spherical particles

B1: Aluminum oxide particles (Admafine AO502 manufactured by Admatechs Co., Ltd. Mohs hardness 9, average particle size 0.4 μm

B2: Aluminum oxide particles (. Co. Admatechs made ADMAFINE ΑΟ502 Mohs Hardness 9, the average particle diameter of 0. 4 _i um) and ultramarine blue particles (first chromatography Kasei E Industry Co. ultramarine N _O .2200 24776 (Mass ratio) with Mohs hardness of 5 and average particle size of 1.4 111)

Β3: Composite oxide spherical particles (Blue 1024 _o Mohs hardness 7-8, average particle size 0.6 m, manufactured by Asahi Sangyo Co., Ltd.)

B4: Aluminum borate particles (Albolite PF03 manufactured by Shikoku Kasei Kogyo Co., Ltd. Mohs hardness 7, average particle size 2.5 m)

[0067] (C) PTFE particles CI: Modified PTFE dispersion (average particle size 0.25 ^ m, melt creep viscosity 8.7 X 10 ⁹ Pa 's, standard specific gravity 2. 165, 60 mass% dispersion)

[0068] (D) Aqueous medium

D1: Pure water

[0069] (E) Nonionic surfactant

E1: Surfynol 440 manufactured by Air Products

[0070] (F) Other fluorinated resin particles

Fl: FEP particles (average particle size 0.23 μm, 63% by weight dispersion)

[0071] Examples 1-6

Using the components and amounts shown in Table 1, an aqueous dispersion composition for a primer was prepared as follows.

[0072] First, ceramic spherical particles (B) were added to the polyamideimide aqueous dispersion (A) and dispersed by a sand mill to prepare a filler dispersion.

[0073] Separately, an aqueous dispersion of modified PTFE particles (C), an aqueous dispersion of FEP particles (F), and a nonionic interface in a carbon mill base (an aqueous dispersion in which carbon black is dispersed with a surfactant). After adding the activator (E), the above filler dispersion was gradually added while stirring. Moreover, if necessary, the viscosity was adjusted by adding pure water (D) additionally.

[0074] The primer-prepared aqueous dispersion compositions prepared in Examples 1 to 6 on a pure aluminum plate (described in JIS H4000 !, A1050) with a blasted surface have a dry film thickness of 10 m. Spray primer and dry at about 150 ° C for 15 minutes to form a primer layer

[0075] On this primer layer, an aqueous dispersion composition for topcoat of the following formulation was spray-coated to a dry film thickness of 20 m, dried at about 80 ° C for 15 minutes, and then 380 ° A topcoat layer was formed by baking at C for 20 minutes.

[0076] The resulting two-layer coating film was subjected to a cross cut test, a substrate peeling test (room temperature, 200 ° C), an interlayer peeling test (room temperature, 200 ° C), and a DuPont impact test. . The results are shown in Table 1.

[0077] (Aqueous dispersion composition for top coat) (component)

Modified PTFE (60% strength by weight) Glycerin

Depolymerizable acrylic resin emulsion (40 Dispanol TOC

Thickener

1]

table 1

Industrial applicability

According to the present invention, it is possible to form a primer layer that is excellent in interlayer adhesion with a topcoat layer containing fluorine resin and can improve the hardness and wear resistance of the entire coating film, and has a high strength fluorine. Even a two-layer structure can be formed with a resin film structure.

Claims

The scope of the claims

[1] Including (A) water-soluble and curable polyamideimide and Z or polyimide binder polymer, (B) spherical ceramic particles, (C) modified polytetrafluoroethylene particles and (D) aqueous medium In the aqueous dispersion composition for a primer of the fluororesin coating layer, the modified polytetrafluoroethylene particle (C) force has a melt creep viscosity of 2 × 10 ⁹ to l × 10 ^u Pa's at 380 ° C. An aqueous dispersion composition for a primer, wherein the composition is modified polytetrafluoroethylene particles having a standard specific gravity of 2.170 or less.

[2] The aqueous dispersion composition for a primer according to [1], wherein the modified amount of the modified polytetrafluoroethylene particles is 0.01% by mass or more.

[3] Mass ratio (C) / (A) force of the water-soluble and curable polyamideimide-based and Z- or polyimide-based binder polymer (A) to polytetrafluoroethylene particles (C) 60/40 The aqueous dispersion composition for a primer according to claim 1 or 2, which is in the range of 80Z20.

[4] The primer according to any one of claims 1 to 3, which has an acid value of 0 to 90 mgKOHZg of the water-soluble and curable polyamideimide-based and Z- or polyimide-based binder polymer (A). Aqueous dispersion composition.

[5] The ceramic spherical particles (B) are contained in a range of 50 to 250% by volume of the water-soluble and curable polyamideimide-based and Z- or polyimide-based noder polymer (A). The aqueous dispersion composition for a primer according to any one of to 4.

[6] The aqueous dispersion composition for a primer according to any one of claims 1 to 5, further comprising a nonionic surfactant (E).

7. The aqueous dispersion composition for a primer according to claim 6, wherein the nonionic surfactant (E) is a polyoxyethylene alkyl ether surfactant.

[8] Further, as fluororesin-based particles (F), tetrafluoroethylene monoperfluoro (alkyl vinyl ether) copolymer particles, tetrafluoroethylene monohexafluoropropylene copolymer particles, and The aqueous dispersion composition for a primer according to any one of claims 1 to 7, comprising polytetrafluoroethylene particles other than Z or the modified polytetrafluoroethylene particles (C).

[9] The primer-based aqueous dispersion composition according to any one of [1] to [8], wherein the primer is used for a primer layer of a topcoat layer containing a fluorine resin containing a perhaloolefin unit.

[10] The aqueous dispersion composition for a primer according to claim 9, wherein the fluorine resin of the topcoat layer contains modified polytetrafluoroethylene particles.

[11] The aqueous dispersion composition for a primer according to claim 9 or 10, wherein the fluorine resin in the topcoat layer comprises a tetrafluoroethylene perfluoro (alkyl vinyl ether) copolymer as a coating film forming component. .

[12] A primer layer for a fluororesin coating layer obtained by applying the aqueous dispersion composition for a primer according to any one of claims 1 to 11 to a substrate.

[13] A coating film structure comprising the primer layer according to claim 12 and a layer structure provided immediately above the primer layer and having a fluorine resin topcoat layer force.

[14] A coated article having the coating film structure according to claim 13 on its surface.