Powder composition, laminate, method for producing laminate, and article

Abstract

The present invention provides a powder composition which enables the achievement of more excellent adhesion and more excellent flame retardancy when used as a primer for fluororesin coating. Provided is a powder composition which contains a fluorine-containing copolymer powder and an epoxy resin powder, said powder composition being characterized in that: the fluorine-containing copolymer has, as essential constituent units, a polymerization unit (A) that is based on tetrafluoroethylene, a polymerization unit (B) that is based on ethylene, and a polymerization unit (C) that is based on a hydrocarbon-based olefin having 3 or more carbon atoms and represented by general formula (1); and the ratio of the polymerization unit (A), the polymerization unit (B), and the polymerization unit (C) satisfies (A) / (B) / (C) = 58-66 / 32-41 / 1-4 (mol%).　(1): CH2 = CX(CF2)nY (In the formula, X and Y are each independently a hydrogen atom or a fluorine atom, and n is an integer of 1 to 8.)

Description

Powder composition, laminate, method for producing laminate, and article

[0001] The present disclosure relates to powder compositions, laminates, methods for making laminates, and articles.

[0002] In order to impart corrosion resistance to substrates used in equipment used in semiconductor manufacturing, chemical plants, steel plants, and the like, coating with a fluororesin film is practiced. In such coating, a primer is used to improve adhesion between the metal substrate and the fluororesin film (Patent Documents 1 and 2).

[0003] Fluororesin coatings are also widely used in powder coatings. When using such powder coatings, it is preferable to also use a powder coating as a primer, since the primer coating can be performed using the same equipment. Patent Document 3 discloses a primer containing a fluororesin and an epoxy resin.

[0004] International Publication No. 2002 / 090450, Japanese Patent Application Laid-Open No. 2008-45140, International Publication No. 2015 / 087813

[0005] An object of the present disclosure is to provide a powder composition that provides superior adhesion and flame retardancy when used as a primer for fluororesin coatings.

[0006] The present disclosure relates to a powder composition comprising a fluorine-containing copolymer powder and an epoxy resin powder, wherein the fluorine-containing copolymer has polymerized units (A) based on tetrafluoroethylene, polymerized units (B) based on ethylene, and polymerized units (C) based on a hydrocarbon olefin having 3 or more carbon atoms and represented by the following general formula (1) as essential constituent units, and the ratio of polymerized units (A), polymerized units (B), and polymerized units (C) is (A) / (B) / (C)=58 to 66 / 32 to 41 / 1 to 4 (mol %). ２ =CX(CF ２ ) ｎ Y (1) (wherein X and Y are each independently a hydrogen atom or a fluorine atom, and n is an integer of 1 to 8.)

[0007] The fluorine-containing copolymer preferably does not contain a polymerized unit having an acid anhydride residue and a polymerizable unsaturated bond. The fluorine-containing copolymer preferably has a melting point of 210 to 250°C. The mass ratio of the fluorine-containing copolymer powder to the epoxy resin powder is preferably 60 / 40 to 99 / 1. The fluorine-containing copolymer powder preferably has an average particle size of 30 to 100 μm. The epoxy resin powder preferably has an average particle size of 30 to 100 μm.

[0008] The powder composition preferably further contains a coloring pigment. The content of the coloring pigment is preferably 1 to 10 mass % based on the total mass of the powder composition. The hydrocarbon olefin having 3 or more carbon atoms represented by the general formula (1) is CH ２ =CF(CF ２ ) ３ Preferably, the powder composition is H, the ratio of polymerized units (A), polymerized units (B), and polymerized units (C) is (A) / (B) / (C)=60-65 / 33-38 / 1-3 (mol %), the total content of polymerized units (A), polymerized units (B), and polymerized units (C) is 98.5-100 mol % based on the total amount of constituent units of the fluorine-containing copolymer, the melt flow rate of the fluorine-containing copolymer is 5-20 g / 10 min, the average particle size of the fluorine-containing copolymer powder is 50-100 μm, the average particle size of the epoxy resin powder is 30-100 μm, and the ratio of the fluorine-containing copolymer powder to the total mass of the fluorine-containing copolymer powder and the epoxy resin powder is 40-99 mass %. The powder composition is preferably a primer composition.

[0009] The present disclosure also relates to a laminate having a primer film formed from the above-mentioned powder composition and a fluororesin film formed on the primer film.The present disclosure also relates to a method for producing the above-mentioned laminate, comprising the steps of forming a primer film from the above-mentioned powder composition and forming a fluororesin film on the primer film from a composition containing a fluorinated copolymer.The present disclosure also relates to an article having the above-mentioned laminate.

[0010] The powder composition of the present disclosure, when used as a primer for fluororesin coating, provides better adhesion and has excellent flame retardancy.

[0011] The present disclosure will be described in detail below. The powder composition of the present disclosure contains a fluorine-containing copolymer powder and an epoxy resin powder.

[0012] (Fluorine-Containing Copolymer) The fluorine-containing copolymer used in the powder composition of the present disclosure has, as essential constituent units, polymerization units (A) based on tetrafluoroethylene, polymerization units (B) based on ethylene, and polymerization units (C) based on a hydrocarbon olefin having 3 or more carbon atoms and represented by the above general formula (1), in a specific ratio.

[0013] That is, an ethylene / tetrafluoroethylene copolymer (ETFE) containing copolymerization units at a specific ratio is used. The use of such ETFE is preferable in that adhesion and flame retardancy are improved. Hereinafter, the fluorine-containing copolymer used in the powder composition of the present disclosure may be simply referred to as "ETFE".

[0014] The hydrocarbon olefin having 3 or more carbon atoms used in the present disclosure is represented by the following general formula (1).

[0015] CH ２ =CX(CF ２ ) ｎ Y (1) (wherein X and Y are each independently a hydrogen atom or a fluorine atom, and n is an integer of 1 to 8.)

[0016] By using a copolymer containing the structural unit (C), the stress crack resistance of the coating is improved, and the life of the coating can be extended, which is preferable.

[0017] The compound represented by the general formula (1) is not particularly limited, and examples thereof include CH ２ =CF(CF ２ ) ２ H, CH ２ =CF(CF ２ ) ３ H, CH ２ =CF(CF ２ )４ Among them, CH ２ =CF(CF ２ ) ３ In the hydrocarbon olefin, the upper limit of the carbon number is not particularly limited, but it can be, for example, 10 or less or 5 or less.

[0018] In the above-mentioned ETFE, the ratio (content ratio) of the polymerized units (A) to (C) is (A) / (B) / (C)=58 to 66 / 32 to 41 / 1 to 4 (mol%). By making it within such a range, it is preferable in that it has excellent adhesion when used as a primer.

[0019] The lower limit of the content of the polymerized units (A) is more preferably 59 mol%, and even more preferably 60 mol%, and the upper limit of the content of the polymerized units (A) is more preferably 65 mol%, and even more preferably 64 mol%.

[0020] The lower limit of the content of the polymerized units (B) is more preferably 33 mol %, and even more preferably 34 mol %. The upper limit of the content of the polymerized units (B) is more preferably 40 mol %, and even more preferably 38 mol %.

[0021] The lower limit of the content of the polymerized units (C) is more preferably 1.5 mol%, and even more preferably 2.0 mol%, and the upper limit of the content of the polymerized units (C) is more preferably 3.5 mol%, and even more preferably 3.0 mol%.

[0022] The ETFE may have only polymerized units (A), (B), and (C) as structural units. Alternatively, the ETFE may have, in addition to the polymerized units (A), (B), and (C), structural units other than these. In the ETFE, the total content of the polymerized units (A), (B), and (C) is preferably 90 to 100 mol% relative to the total amount of the structural units of ETFE. The lower limit of the total content of the polymerized units (A), (B), and (C) is preferably 95 mol%, more preferably 98.5 mol%, even more preferably 99.0 mol%, and even more preferably 99.5 mol%.

[0023] The ETFE preferably does not contain a polymerization unit having an acid anhydride residue and a polymerizable unsaturated bond. The polymerization unit having an acid anhydride residue and a polymerizable unsaturated bond is not particularly limited, but examples thereof include maleic anhydride, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride. If the ETFE does not contain a polymerization unit having an acid anhydride residue and a polymerizable unsaturated bond, the adhesive functional group of the epoxy resin is not consumed by these in the heating step during film formation, and therefore, it is preferable in that high adhesion to the metal substrate can be obtained.

[0024] The ETFE particles contained in the ETFE powder preferably have an average particle size of 30 to 150 μm. When the average particle size is 30 μm or more, the film-forming properties of the resulting primer film are improved, making it easier to form a thick primer film. When the average particle size is 150 μm or less, the uniform dispersion of ETFE in the primer film is improved, making it possible to suppress a decrease in adhesion to a fluororesin film (e.g., an ETFE coating film) formed on the primer film. The preferred lower limit of the average particle size is 31 μm, more preferably 32 μm, even more preferably 50 μm, and even more preferably 70 μm. The preferred upper limit of the average particle size is 120 μm, more preferably 100 μm. The average particle size is a value measured by laser diffraction.

[0025] The ETFE constituting the ETFE particles preferably has a melt flow rate (MFR) of 0.1 to 100 g / 10 min. Within this range of melt flow rate, the adhesion between the resulting primer film and a fluororesin film (e.g., an ETFE coating film) is further improved due to the flow properties of the ETFE. Furthermore, stress cracking and stress cracking are less likely to occur in the primer film, improving corrosion resistance. The melt flow rate has a more preferred lower limit of 0.5 g / 10 min, an even more preferred lower limit of 1.0 g / 10 min, and a particularly preferred lower limit of 5.0 g / 10 min. The more preferred upper limit is 50 g / 10 min, an even more preferred upper limit is 30 g / 10 min, a particularly preferred upper limit is 25 g / 10 min, and a most preferred upper limit is 20 g / 10 min. The ETFE can be made to have a melt flow rate within the above range by adjusting the copolymerization composition and molecular weight, which will be described later. In this specification, the melt flow rate is a value measured in accordance with ASTM D3159 at a temperature of 297°C under a load of 5 kg.

[0026] ETFE preferably has a melting point of 200°C or higher. When the melting point is within the above range, deformation is unlikely to occur when used at high temperatures, and heat resistance is improved. The melting point is more preferably above 200°C, even more preferably 205°C or higher, and particularly preferably 210°C or higher. The upper limit of the melting point is not particularly limited, but may be 220°C, 250°C, or 280°C. The melting point is the temperature at the peak of the endothermic curve obtained by performing heat measurement at a heating rate of 10°C / min using a differential scanning calorimeter in accordance with ASTM D-4591.

[0027] ETFE can be obtained by copolymerization, for example, by a conventionally known polymerization method such as suspension polymerization.The ETFE powder obtained by copolymerization is pulverized as necessary so as to have an average particle size within the above-mentioned range.The pulverization method is not particularly limited, and for example, a conventionally known method such as that disclosed in JP-A-63-270740 can be used.For example, the ETFE powder can be compressed into a sheet shape with a roll, pulverized with a pulverizer, and classified.

[0028] (Epoxy Resin) The curable composition of the present disclosure preferably further contains an epoxy resin. The epoxy resin is preferably a non-fluorine-containing epoxy resin. The epoxy resin is preferably in a solid state, and specific examples include commonly used non-fluorine-containing epoxy resins such as bisphenol A epoxy resins, brominated bisphenol A epoxy resins, and novolac epoxy resins. As mentioned above, examples of non-fluorine-containing epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, and epoxy resins containing an isocyanurate ring, as well as bisphenol A epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, naphthalene epoxy resins, biphenyl epoxy resins, phenol aralkyl epoxy resins, biphenyl aralkyl epoxy resins, hydrogenated epoxy resins in which the aromatic rings of the various epoxy resins have been hydrogenated, and dicyclopentadiene epoxy resins. In particular, as the non-fluorine-containing epoxy resin, bisphenol epoxy resins are preferred, and bisphenol A epoxy resins are more preferred.

[0029] The epoxy resin is in a powder state, and preferably has an average particle size of 30 to 100 μm. A particle size within this range is preferable in that good film formation can be achieved. If the average particle size is too small, the film-forming properties of the resulting primer film are likely to be reduced, making it difficult to form a thick primer film. If the average particle size is too large, the epoxy resin may lack uniform dispersion in the primer film, resulting in reduced adhesion to the ETFE coating film formed on the primer film. The preferred lower limit of the average particle size is 32 μm, more preferably 34 μm, and the preferred upper limit is 90 μm, more preferably 80 μm. The average particle size is a value measured by laser diffraction.

[0030] The epoxy resin preferably has an epoxy equivalent of 500 to 4000. The lower limit of the epoxy equivalent is preferably 550, more preferably 600, and the upper limit is preferably 3000, more preferably 2000. The epoxy equivalent is determined in accordance with JIS 7236.

[0031] The mass ratio of the fluorine-containing copolymer powder to the epoxy resin powder is preferably 40 / 60 to 99 / 1, more preferably 50 / 50 to 99 / 1, even more preferably 60 / 40 to 99 / 1, still more preferably 60 / 40 to 97 / 3, and even more preferably 60 / 40 to 95 / 5.

[0032] In the powder composition of the present disclosure, the proportion of the fluorine-containing copolymer powder relative to the total mass of the fluorine-containing copolymer powder and the epoxy resin powder is preferably 40 to 99% by mass. The lower limit of the proportion of the fluorine-containing copolymer powder is more preferably 50% by mass, and even more preferably 60% by mass. The upper limit of the proportion of the fluorine-containing copolymer powder is more preferably 97% by mass, and even more preferably 95% by mass.

[0033] In the powder composition of the present disclosure, the proportion of the fluorine-containing copolymer powder relative to the total mass of the fluorine-containing copolymer powder and the epoxy resin powder may be 40 to 70 mass%. The upper limit of the proportion of the fluorine-containing copolymer powder may be 69 mass%. Even when the proportion of the fluorine-containing copolymer powder is 40 to 70 mass% (when the content of the epoxy resin powder is relatively high), the powder composition of the present disclosure can exhibit excellent adhesive ability.

[0034] The powder composition of the present disclosure may contain only a fluorine-containing copolymer powder and an epoxy resin powder. Alternatively, the powder composition of the present disclosure may further contain, in addition to the fluorine-containing copolymer powder and the epoxy resin powder, components other than these (hereinafter sometimes referred to as "other components"). The total content of the fluorine-containing copolymer powder and the epoxy resin powder is preferably 75% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 93% by mass or more, based on the total amount of the powder composition. The total content of the fluorine-containing copolymer powder and the epoxy resin powder is preferably 100% by mass or less, more preferably less than 100% by mass, even more preferably 99.9% by mass or less, and even more preferably 99.5% by mass or less, based on the total amount of the powder composition. Examples of other components include heat stabilizers, color pigments, etc.

[0035] (Thermal Stabilizer) The powder composition of the present disclosure may contain a thermal stabilizer capable of preventing deterioration of the fluorine-containing copolymer during a film-forming process by heating. Examples include copper compounds, thiazole compounds, benzimidazole compounds, and aromatic amine compounds. The thermal stabilizer is preferably contained in a proportion of 0.0001 to 5 mass% of the entire powder composition. The upper limit of the content of the thermal stabilizer is more preferably 4 mass%, and even more preferably 3 mass%. The lower limit of the content of the thermal stabilizer is more preferably 0.0002 mass%, and even more preferably 0.0003 mass%.

[0036] (Coloring Pigment) The powder composition of the present disclosure may contain a coloring pigment. Examples of coloring pigments include titanium oxide, cobalt oxide, cobalt aluminate (e.g., cobalt blue), carbon (e.g., carbon black), chromium oxide, iron oxide, and mica. The coloring pigment is preferably contained in a proportion of 0.1 to 20 mass% of the total powder composition. The coloring pigment may be contained in a resin powder or may be blended as a powdered coloring pigment. The upper limit of the content of the coloring pigment is more preferably 18 mass%, even more preferably 16 mass%, and particularly preferably 10 mass%. The lower limit of the content of the coloring pigment is more preferably 0.2 mass%, even more preferably 0.3 mass%, and particularly preferably 1 mass%. A content of the coloring pigment of 0.5 mass% or more is preferable in terms of improving the flame retardancy of the composition.

[0037] (Method for Producing Powder Composition) The powder composition of the present disclosure can be produced by a known general method. Specific examples include a method of mixing powders composed of the above-mentioned components. Such mixing can be performed using a mixer such as a Henschel mixer, a V-type blender, a rocking mixer, a double cone mixer, or a tumbler mixer.

[0038] (Method of Use) The powder composition of the present disclosure can be suitably used as a primer composition (more specifically, as a primer for a powder coating composition containing ETFE).

[0039] (Laminate) The present disclosure also relates to a laminate having a primer film and a fluorine-containing resin film. The fluorine-containing resin film is formed on the primer film directly or via another layer. In other words, the laminate of the present disclosure has a primer film and a fluorine-containing resin film provided on the primer film directly or via another layer. The primer film corresponds to a primer layer, and the fluorine-containing resin film corresponds to, for example, a top coat layer. The primer film is formed from the powder composition of the present disclosure. The fluorine-containing resin film is formed from a top coat (composition for forming a top coat layer). For example, a composition containing a fluorine-containing copolymer can be used as the top coat, and more specifically, a powder coating composition containing ETFE can be used. Any known powder coating composition containing ETFE can be used as the top coat by laminating it with the primer of the present disclosure. It is preferable that the copolymerization units of ETFE contained in the powder coating composition used as the top coat are similar to or identical to the copolymerization units of ETFE contained in the primer of the present invention, in terms of improving the adhesion between the primer layer and the top coat layer.

[0040] (Method of Manufacturing Laminate) The present disclosure also relates to a method of manufacturing a laminate. The method of manufacturing a laminate of the present disclosure includes, for example, a step of forming a primer film and a step of forming a fluororesin film. In the step of forming a primer film, a primer film is formed using the powder composition of the present disclosure. In the step of forming a fluororesin film, a fluororesin film is formed on the primer film using the top coat. In the step of forming a primer film, the coating method when applying the powder composition of the present disclosure to a substrate is not particularly limited, but electrostatic coating is preferred. After electrostatic coating, a coating film (primer film) can be formed by heating, and then a top coat (e.g., ETFE powder paint) can be applied. The heating is preferably performed at 250 to 350°C.

[0041] (Substrate) The powder composition of the present disclosure is not particularly limited to a substrate to be coated, but can be suitably used for coating metal substrates such as iron and stainless steel, for example.

[0042] (Article) The present disclosure also relates to an article comprising the laminate. The article of the present disclosure has, for example, a substrate, a primer coating, and a fluororesin coating. The primer coating is provided on the substrate directly or via another layer, and is formed from the powder composition of the present disclosure. The fluororesin coating is provided on the primer coating directly or via another layer. Examples of the article of the present disclosure include equipment used in semiconductor manufacturing, equipment used in chemical plants, and equipment used in steel plants.

[0043] (Field of Use) The powder composition of the present disclosure can be suitably used for primer coating in fields such as equipment used in semiconductor manufacturing, chemical plants, and steel plants.

[0044] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following examples, unless otherwise specified, "parts" and "%" represent "parts by mass" and "% by mass", respectively.

[0045] The raw material powders were mixed according to the composition (unit: parts by mass) shown in the table to obtain a powder composition. Using this powder composition, the peel strength was evaluated by the following procedure. The components shown in the table were as follows: Fluorine-containing copolymer powder A: TFE / ethylene / structural unit (C) = 64 / 34 / 2 (mol%) MFR: 13 (g / 10 min) Average particle size: 75 μm Fluorine-containing copolymer powder B: TFE / ethylene / structural unit (C) = 64 / 34 / 2 (mol%) MFR: 13 (g / 10 min) Average particle size: 137 μm Fluorine-containing copolymer powder C: TFE / ethylene / structural unit (C) = 55 / 43 / 2 (mol%) MFR: 22 (g / 10 min) Average particle size: 69 μm The structural unit (C) was CH ２ =CF(CF ２ ) ３Epoxy resin E: bisphenol type, epoxy equivalent: 860, average particle size: 38 μm Heat stabilizer F: copper (II) oxide manufactured by Kanto Chemical Co., Ltd. Heat stabilizer G: Nocrac White (aromatic amine compound) manufactured by Ouchi Shinko Chemical Co., Ltd. Carbon black: Black Pearl 4350 manufactured by Cabot Corporation Titanium oxide: Tipure R-960 manufactured by Chemours Co., Ltd. Cobalt blue: Cobalt Blue 1024 manufactured by Asahi Kasei Co., Ltd.

[0046] (Peel Strength) A stainless steel plate (SUS304, surface roughness Ra: 2-3 μm) was blasted with alumina powder (Ujiden Chemical Industry Co., Ltd., Tosa Emery #40) at a spray pressure of 1.0 MPa. The primer compositions shown in Tables 1 and 2 were electrostatically coated to a film thickness of 50 μm after baking, and the plate was baked at 340 °C for 30 minutes. A 600 μm-thick baked film made of the top coat composition shown in Tables 1 and 2 was then applied to the resulting film to obtain a laminate. After making a 10 mm-wide cut in this laminate, the peel strength was measured at a 90° direction relative to the test piece using a Tensilon universal testing machine at a tensile speed of 50 mm / min in accordance with JIS K 6854-1. A peel strength of 80 N / cm or more was judged to be acceptable.

[0047] (Flame Retardancy) A powder composition was electrostatically coated onto a stainless steel plate (SUS304, surface roughness Ra: 2-3 μm) that had been blasted with alumina powder (Tosa Emery #40, manufactured by Ujiden Chemical Industry Co., Ltd.) at a spray pressure of 1.0 MPa, so that the film thickness after firing would be 50 μm, and the plate was fired at 340° C. for 30 minutes. A 300 μm-thick fired coating made of the top coat composition shown in Tables 1 and 2 was then formed on the resulting coating to obtain a laminate. The flame spread index of this laminate was evaluated using a radiant panel test based on ASTM E162.

[0048]

[0049]

[0050] The results in Tables 1 and 2 above clearly show that the powder composition of the present disclosure has excellent adhesive properties as a primer. It is also clear that the powder composition of the present disclosure exhibits a low flame spread index and is therefore excellent in flame retardancy. It is also clear that the laminate of the present disclosure exhibits a low flame spread index and is therefore excellent in flame retardancy.

[0051] The powder composition of the present disclosure can be used as a primer for ETFE powder coatings.

Claims

1. A powder composition comprising a fluorine-containing copolymer powder and an epoxy resin powder, wherein the fluorine-containing copolymer has essential structural units of polymerized units (A) based on tetrafluoroethylene, polymerized units (B) based on ethylene, and polymerized units (C) based on a hydrocarbon olefin having 3 or more carbon atoms and represented by the following general formula (1), and the ratio of polymerized units (A), polymerized units (B), and polymerized units (C) is (A) / (B) / (C) = 58-66 / 32-41 / 1-4 (mol %). CH ２ =CX(CF ２ ) ｎ Y (1) (wherein X and Y are each independently a hydrogen atom or a fluorine atom, and n is an integer of 1 to 8.) 2. The powder composition according to claim 1, wherein the fluorine-containing copolymer does not contain polymerized units having an acid anhydride residue and a polymerizable unsaturated bond.

3. The powder composition according to claim 1 or 2, wherein the fluorine-containing copolymer has a melting point of 210 to 250°C.

4. The powder composition according to any one of claims 1 to 3, wherein the mass ratio of the fluorine-containing copolymer powder to the epoxy resin powder is 60 / 40 to 99 / 1.

5. A powder composition according to any one of claims 1 to 4, wherein the fluorine-containing copolymer powder has an average particle size of 30 to 100 µm.

6. A powder composition according to any one of claims 1 to 5, wherein the epoxy resin powder has an average particle size of 30 to 100 μm.

7. The powder composition according to any one of claims 1 to 6, further comprising a color pigment.

8. The powder composition according to any one of claims 1 to 7, wherein the content of the color pigment is 1 to 10 mass % based on the total mass of the powder composition.

9. The hydrocarbon olefin having 3 or more carbon atoms represented by the general formula (1) is CH ２ =CF(CF ２ ) ３ 9. The powder composition according to claim 1, wherein the formula is H; the ratio of polymerized units (A), polymerized units (B), and polymerized units (C) is (A) / (B) / (C)=60-65 / 33-38 / 1-3 (mol %); the total content of polymerized units (A), polymerized units (B), and polymerized units (C) is 98.5-100 mol % based on the total amount of constituent units of the fluorinated copolymer; the melt flow rate of the fluorinated copolymer is 5-20 g / 10 min; the average particle size of the fluorinated copolymer powder is 50-100 μm; the average particle size of the epoxy resin powder is 30-100 μm; and the ratio of the fluorinated copolymer powder to the total mass of the fluorinated copolymer powder and the epoxy resin powder is 40-99 mass %.

10. The powder composition according to any one of claims 1 to 9, which is a primer composition.

11. A laminate having a primer film formed from the powder composition according to any one of claims 1 to 10, and a fluorine-containing resin film formed on the primer film.

12. A method for producing a laminate, comprising: a step of forming a primer film from the powder composition according to any one of claims 1 to 10; and a step of forming a fluororesin film on the primer film from a composition containing a fluorine-containing copolymer.

13. An article comprising the laminate of claim 11.

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