Composition, composition for coating material, and article

Abstract

Provided is a composition containing a fluorine-containing copolymer capable of being adapted to a coating material composition using parachlorobenzotrifluoride. This composition contains a solvent (A) and a fluorine-containing copolymer (B) and is characterized in that the solvent (A) is parachlorobenzotrifluoride (a1) or a mixed solvent of parachlorobenzotrifluoride (a1) and a solvent (a2) having a boiling point of 100°C or less, a ratio (mass ratio) of (a1) / (a2) in the solvent (A) ranges from 50 / 50 to 100 / 0 (where 50 / 50 is excluded), and the fluorine-containing copolymer (B) includes a structural unit (b1) derived from fluoroolefin and a structural unit (b2) derived from at least one selected from the group consisting of vinyl esters, vinyl ethers, allyl ethers, and hydroxyl group-containing unsaturated compounds.

Description

Compositions, paint compositions and articles

[0001] This disclosure relates to compositions, paint compositions, and articles.

[0002] Paints containing fluorine copolymers are used in many fields because they have excellent properties such as weather resistance, stain resistance, water resistance, and solvent resistance. In recent years, the use of solvents mainly composed of parachlorobenzotrifluoride in such paints has been under consideration.

[0003] Patent Document 1 describes a paint composition that combines a specific fluororesin with a solvent that partially comprises parachlorobenzotrifluoride.

[0004] Japanese Patent Publication No. 2001-354911

[0005] The present disclosure aims to provide a composition containing a fluorine-containing copolymer that can be used with paint compositions using parachlorobenzotrifluoride.

[0006] The present disclosure relates to a composition comprising a solvent (A) and a fluorine-containing copolymer (B), wherein the solvent (A) is parachlorobenzotrifluoride (a1), or a mixed solvent of parachlorobenzotrifluoride (a1) and a solvent (a2) having a boiling point of 100°C or less, the ratio (mass ratio) of (a1) / (a2) in the solvent (A) is 50 / 50 to 100 / 0 (excluding 50 / 50), and the fluorine-containing copolymer (B) is characterized by comprising structural units (b1) derived from fluoroolefins and structural units (b2) derived from at least one selected from the group consisting of vinyl esters, vinyl ethers, allyl ethers, and hydroxyl group-containing unsaturated compounds.

[0007] The solvent (a2) having a boiling point of 100°C or less is preferably at least one selected from the group consisting of t-butylacetic acid, dimethyl carbonate, methyl acetate, and acetone. The above composition is preferably such that the mass ratio (B) / (A) of the fluorine-containing copolymer (B) to the solvent (A) is 75 / 25 to 10 / 90. The structural unit (b1) derived from the fluoroolefin is preferably a structural unit derived from at least one selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene. The structural unit (b1) derived from the fluoroolefin is preferably a structural unit derived from tetrafluoroethylene.

[0008] The structural unit (b2) is preferably a structural unit derived from a vinyl ester. The composition of this disclosure may further contain a pigment. The solvent (a2) having a boiling point of 100°C or less is an organic solvent having a boiling point of 80°C or more and 100°C or less, the mass ratio (B) / (A) of the fluorine-containing copolymer (B) to the solvent (A) is 35 / 65 to 15 / 85, the structural unit (b1) derived from a fluoroolefin is a structural unit derived from at least one selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene, and the structural unit (b2) is preferably a structural unit derived from at least one selected from the group consisting of hydroxyl-free vinyl esters and hydroxyl-free vinyl ethers, as well as a structural unit derived from a hydroxyl-containing vinyl ether. This disclosure is also a paint composition containing the above composition. This disclosure is also an article painted with the above composition.

[0009] The compositions disclosed herein, by combining a fluorine-containing copolymer and parachlorobenzotrifluoride, can provide coatings with suitable performance.

[0010] The present disclosure will be described in detail below. The present disclosure relates to a composition containing a specific solvent (A) and a fluorine-containing copolymer (B). The present disclosure provides a paint composition using the specific solvent (A) that can dissolve a resin well and form a coating film.

[0011] The use of parachlorobenzotrifluoride as a solvent in the paint and coatings industry has been increasing in recent years. Furthermore, studies are being conducted on the combined use of such solvents with other solvents.

[0012] In paint compositions using fluorine-based resins, there was a problem in that it became difficult to obtain good film-forming properties when such solvents were used. Due to factors such as the resin's solubility and the evaporation rate of the solvent during film formation, a good film was not formed, and sufficient coating performance could not be obtained.

[0013] This disclosure relates to a composition that improves upon these points and provides a paint composition with good solubility and film-forming properties when a solvent comprising part or all of parachlorobenzotrifluoride (a1) is used.

[0014] Furthermore, the composition of this disclosure may be sold as a composition containing a solvent (A) and a fluorine-containing copolymer (B), or the fluorine-containing copolymer (B) may be sold in a solid state and used by adding and mixing it with solvent (A) at the painting site. Such a composition is preferable in that it reduces the energy required for transporting the product, but on the other hand, good solubility is required so that the polymer can be easily dissolved in the solvent at the painting site. Each component contained in the composition of this disclosure will be described in detail below.

[0015] (Solvent (A)) The compositions of the present disclosure use parachlorobenzotrifluoride (a1), or a mixed solvent of parachlorobenzotrifluoride (a1) and a solvent (a2) having a boiling point of 100°C or less, wherein the ratio (mass ratio) of (a1) / (a2) in solvent (A) is 50 / 50 to 100 / 0 (excluding 50 / 50). In one embodiment, only parachlorobenzotrifluoride (a1) may be used as solvent (A) ((a1) / (a2) = 100 / 0). Alternatively, in another embodiment, a mixed solvent of parachlorobenzotrifluoride (a1) and a solvent (a2) having a boiling point of 100°C or less may be used as solvent (A) (where the ratio (mass ratio) of (a1) / (a2) in the mixed solvent is greater than 50 / 50 and less than 100 / 0).

[0016] In recent years, parachlorobenzotrifluoride (a1), which is becoming widely used as a solvent, is used as an essential solvent component, and if necessary, a solvent (a2) with a boiling point of 100°C or lower may be added to it in a certain proportion.

[0017] (Parachlorobenzotrifluoride (a1)) Parachlorobenzotrifluoride (a1) is a known compound used as a solvent and is a commercially available compound. A commercially available compound can also be used in the compositions of this disclosure. This disclosure provides a composition that can obtain suitable effects even when a solvent mainly composed of parachlorobenzotrifluoride (a1) is used.

[0018] (Solvent (a2) with a boiling point of 100°C or less) In this disclosure, the solvent may contain only parachlorobenzotrifluoride (a1), or it may be a mixed solvent containing a predetermined proportion of solvent (a2) with a boiling point of 100°C or less.

[0019] Such solvents are not particularly limited and can be general ones used in fields such as paints. Organic solvents are preferred as the solvent (a2) with a boiling point of 100°C or lower. Specifically, examples include t-butylacetic acid, dimethyl carbonate, methyl acetate, and acetone, with t-butylacetic acid being more preferred. Two or more of these may be used in combination.

[0020] The boiling point of solvent (a2) is preferably 100°C or lower. The lower limit of the boiling point of solvent (a2) is not particularly limited, but may be, for example, 50°C or higher, or 80°C or higher.

[0021] The inclusion of a solvent (a2) with a boiling point of 100°C or lower allows for adjustment of the evaporation rate during painting. This is preferable because it allows for increasing the amount of (a2) if the evaporation rate needs to be increased.

[0022] When using the solvent (a2) with a boiling point of 100°C or lower, the ratio (mass ratio) of (a1) to (a2) in the solvent is preferably 50 / 50 to 100 / 0 (excluding 50 / 50). When (a2) is blended in a quantity not exceeding 50 / 50, it is preferable in that painting workability is improved and a good coating film can be formed. The solvent (a2) with a boiling point of 100°C or lower may be omitted entirely.

[0023] The lower limit of the content of parachlorobenzotrifluoride (a1) in the above solvent in the ratio of (a1) / (a2) is preferably 55, more preferably 60, and even more preferably 65. In other words, when solvent (A) is a mixed solvent, the content of parachlorobenzotrifluoride (a1) is more than 50% by mass, preferably 55% by mass or more, more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more, based on the total mass of parachlorobenzotrifluoride (a1) and solvent (a2). When solvent (A) is a mixed solvent, the content of parachlorobenzotrifluoride (a1) is less than 100% by mass, preferably 95% by mass or less, and more preferably 90% by mass or less, based on the total mass of parachlorobenzotrifluoride (a1) and solvent (a2).

[0024] The compositions of this disclosure may contain solvents other than the solvents (a1) and (a2) described above. The content of the other solvents is preferably 20% by mass or less of the total amount of solvent. The solvents contained in the composition greatly affect the coating performance. Therefore, when using other solvents, it is preferable to keep the amount within a range that does not impair the performance of the compositions of this disclosure. The compositions may also contain no other solvents at all.

[0025] The composition of this disclosure preferably contains the solvent (A) in an amount of 15 to 75% by mass relative to the total amount of the composition. By keeping the amount within this range, it is possible to obtain the effect of having excellent coating properties and forming a coating film of an appropriate thickness. The lower limit of the above blending amount is more preferably 20% by mass, even more preferably 30% by mass, particularly preferably 40% by mass, and most preferably 50% by mass. The upper limit of the above blending amount is more preferably 70% by mass, and even more preferably 68% by mass.

[0026] (Fluorine-containing copolymer (B)) The compositions of the present disclosure contain a fluorine-containing copolymer (B). The fluorine-containing copolymer (B) has excellent properties such as weather resistance and solvent resistance, and the present disclosure relates to compositions that can exhibit the properties of such a fluorine-containing copolymer.

[0027] The fluorine-containing polymer (B) of this disclosure has a structural unit (b1) derived from a fluoroolefin and a structural unit (b2) derived from at least one monomer (e.g., one, two, three, four, or five) selected from the group consisting of vinyl esters, vinyl ethers, allyl ethers, and hydroxyl group-containing unsaturated compounds. Such a polymer is preferable because it can be easily dissolved in the solvent (A) described above.

[0028] The structural unit (b1) derived from fluoroolefins refers to a structure derived from an unsaturated compound containing a fluorine atom. Specifically, examples include tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, hexafluoropropylene, and pentafluoropropylene, which can be appropriately selected depending on the properties required for the coating film and the combination with copolymer components. Furthermore, one or more of these fluoroolefins can be used. In particular, it is preferable to use structural units derived from at least one monomer (e.g., one or two) selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene, and it is more preferable to use structural units derived from tetrafluoroethylene.

[0029] In addition to the structural units (b1) derived from the fluoroolefin, the above-mentioned fluorine-containing copolymer (B) also contains structural units (b2) selected from at least one of the group consisting of vinyl esters, vinyl ethers, allyl ethers, and hydroxyl group-containing unsaturated compounds, in order to lower the melting point and softening point of the fluorine-containing copolymer, further improve paintability, and impart appropriate physical properties such as hardness, flexibility, and gloss to the coating film.

[0030] The following are specific examples of materials that can be used as the vinyl esters, vinyl ethers, allyl ethers, and hydroxyl group-containing unsaturated compounds mentioned above. Note that vinyl esters, vinyl ethers, and allyl ethers may each be hydroxyl-free compared to hydroxyl group-containing unsaturated compounds. Examples of vinyl ethers include alkyl vinyl ethers, more specifically ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, and cyclohexyl vinyl ether. The alkyl group of the alkyl vinyl ether may be linear or cyclic. Examples of vinyl esters include alkyl vinyl esters (esters of alkyl carboxylic acid and vinyl alcohol), more specifically vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl valerate, vinyl cyclohexanecarboxylate, vinyl benzoate, p-t-butylbenzoate, vinyl versatate, and vinyl neononanoate. Examples of the allyl ethers mentioned above include alkyl allyl ethers, and more specifically, ethyl allyl ether, propyl allyl ether, butyl allyl ether, isobutyl allyl ether, cyclohexyl allyl ether, and the like. The alkyl group of the alkyl allyl ether may be linear or cyclic. Examples of the hydroxyl group-containing monomers mentioned above include vinyl monomers having hydroxyl groups.More specifically, examples include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, hydroxyisobutyl vinyl ether, and hydroxycyclohexyl vinyl ether; esters of hydroxyalkyl carboxylic acids with vinyl alcohols such as vinyl hydroxyacetate, vinyl hydroxypropioate, vinyl hydroxybutyrate, vinyl hydroxyvalerate, vinyl hydroxyisobutyrate, and vinyl hydroxycyclohexanecarboxylate; hydroxyalkyl allyl ethers such as hydroxyethyl allyl ether, hydroxypropyl allyl ether, hydroxybutyl allyl ether, hydroxyisobutyl allyl ether, and hydroxycyclohexyl allyl ether; hydroxyalkyl allyl esters such as hydroxyethyl allyl ester, hydroxypropyl allyl ester, hydroxybutyl allyl ester, hydroxyisobutyl allyl ester, and hydroxycyclohexyl allyl ester; hydroxyalkyl esters of acrylic acid or methacrylic acid such as 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and hydroxypropyl methacrylate; and one or more of these partially fluorine-substituted compounds.

[0031] The structural unit (b2) is preferably a structural unit derived from a vinyl ester, and more preferably a structural unit derived from vinyl benzoate, vinyl versatate, or vinyl neononanoate ester. The structural unit (b2) may also preferably be a structural unit derived from at least one monomer selected from the group consisting of vinyl esters (e.g., hydroxyl-free vinyl esters) and vinyl ethers (e.g., hydroxyl-free vinyl ethers), and a structural unit derived from a hydroxyl-containing unsaturated compound.

[0032] The fluorine-containing polymer (B) described above may have constituent units derived from monomers other than those described above, to the extent that it does not impair the purpose of this disclosure. Examples of other monomers include constituent units based on monomers having carboxyl groups.

[0033] Examples of monomers having the carboxyl group mentioned above include α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, succinic acid, succinic anhydride, fumaric acid, fumaric anhydride, crotonic acid, maleic acid, and maleic anhydride, as well as fluorine-substituted monomers such as perfluorobutenoic acid.

[0034] Other monomers include acrylic esters and allyl ethers. Examples of acrylic esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, (iso)butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of allyl ethers include ethyl allyl ether, propyl allyl ether, butyl allyl ether, isobutyl allyl ether, and cyclohexyl allyl ether. One or more of these may be used.

[0035] In the above-mentioned fluorine-containing copolymer (B), the structural units (b1) derived from fluoroolefins are preferably 1 to 60% of the total polymerization units constituting the polymer. By keeping the amount within this range, a composition with excellent weather resistance and solvent resistance can be obtained. The lower limit of the above-mentioned amount is more preferably 30% by mass, and even more preferably 40% by mass. The upper limit of the above-mentioned amount is more preferably 60% by mass, and even more preferably 50% by mass.

[0036] In the above-mentioned fluorine-containing copolymer (B), it is preferable that the structural unit (b2) derived from at least one selected from the group consisting of vinyl esters, vinyl ethers, allyl ethers, and hydroxyl group-containing unsaturated compounds constitutes 1 to 60% by mass of the total polymerization units constituting the polymer. By keeping it within this range, a composition with excellent solvent solubility and further excellent pigment dispersibility can be obtained. The lower limit of the above-mentioned blending amount is more preferably 5% by mass, and even more preferably 10% by mass. The upper limit of the above-mentioned blending amount is more preferably 60% by mass, and even more preferably 55% by mass.

[0037] If the above-mentioned fluorine-containing copolymer (B) has hydroxyl groups, the hydroxyl value is preferably 10 to 200. In particular, when used in combination with a curing agent, it is especially preferable to have the value within this range in order to allow the reaction with the curing agent to proceed favorably. The lower limit of the above-mentioned hydroxyl value is more preferably 20, and even more preferably 30. The upper limit of the above-mentioned hydroxyl value is more preferably 170, and even more preferably 140.

[0038] If the above-mentioned fluorine-containing copolymer (B) has carboxyl groups, the acid value of the fluorine-containing copolymer (B) is preferably 1 to 60 mg KOH / g. Having such an acid value is preferable in that it effectively suppresses the increase in viscosity of the composition. The lower limit of the above acid value is more preferably 2 mg KOH / g, and even more preferably 3 mg KOH / g. The upper limit of the above acid value is more preferably 50 mg KOH / g, and even more preferably 40 mg KOH / g. If the constituent units are based on monomers having carboxyl groups, the content of constituent units based on monomers having carboxyl groups is preferably 0.1 mol% or more, and more preferably 0.5 mol% or more, relative to the total amount of structural units constituting the fluorine-containing copolymer (B). Furthermore, the content of constituent units based on monomers having carboxyl groups is preferably 10 mol% or less, and more preferably 5 mol% or less, relative to the total amount of structural units constituting the fluorine-containing copolymer (B). In terms of improving the dispersibility of the pigment and the stability of the composition, it is preferable that the content of constituent units based on monomers having carboxyl groups be within the above range.

[0039] If the fluorine-containing polymer (B) has constituent units other than (b1) and (b2) above, it is preferable that the monomer is present in a proportion of less than 10% by mass.

[0040] The composition of the present disclosure preferably contains the fluorine-containing polymer (B) in a proportion of 1 to 85% by mass based on the total amount of the composition. By setting it within such a range, it is possible to obtain the effect of forming a coating film having fluorine weather resistance, solvent solubility, paintability, and hardness. The lower limit of the above blending amount is more preferably 5% by mass, and even more preferably 10% by mass. The upper limit of the above blending amount is more preferably 75% by mass, even more preferably 50% by mass, particularly preferably 40% by mass, and most preferably 30% by mass.

[0041] In the composition of the present disclosure, the mass ratio (B) / (A) of the fluorine-containing copolymer (B) to the solvent (A) is preferably 75 / 25 to 5 / 95. The lower limit of the above mass ratio is more preferably 10 / 90, and even more preferably 15 / 85. The upper limit of the above blending amount is more preferably 65 / 35, even more preferably 50 / 50, and particularly preferably 35 / 65. The content of the fluorine-containing copolymer (B) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more based on the total mass of the solvent (A) and the fluorine-containing copolymer (B). The content of the fluorine-containing copolymer (B) is preferably 75% by mass or less, more preferably 65% by mass or less, and even more preferably 50% by mass or less based on the total mass of the solvent (A) and the fluorine-containing copolymer (B).

[0042] (Other components) The composition of the present disclosure may contain other components as necessary. The other components that can be blended with the composition of the present disclosure are not particularly limited, and examples thereof include curing agents, curing catalysts, pigments, pigment dispersants, thickeners, leveling agents, defoamers, film-forming aids, ultraviolet absorbers, HALS, matting agents, fillers, colloidal silica, antifungal agents, silane coupling agents, anti-skinning agents, antioxidants, flame retardants, anti-sagging agents, antistatic agents, rust preventives, water-soluble resins (such as polyvinyl alcohol and polyethylene oxide), preservatives, antifreeze agents, and other paint additives.

[0043] (Hardener) As described above, the composition of the present disclosure may contain a hardener or may be composed of a hydroxyl group-containing polymer. In this case, the curing reaction can also be caused by this hydroxyl group.

[0044] The hardener that can be used in the composition of the present disclosure is not particularly limited, and examples include polyisocyanate compounds, amino resins, and silicate compounds. Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine methyl ester diisocyanate, methylcyclohexyl diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, n-pentane-1,4-diisocyanate, trimers thereof, adducts thereof, biuret bodies and isocyanurate bodies, polymers thereof having two or more isocyanate groups, and further blocked isocyanates, etc., but are not limited thereto. Among the above polyisocyanate compounds, hexamethylene diisocyanate is preferred. Examples of the polyisocyanate compound include Desmodur N3300 (manufactured by Covestro), Desmodur N3900 (manufactured by Covestro), Duranate TPA-100, etc. (manufactured by Asahi Kasei).

[0045] The composition of the present disclosure preferably contains the above hardener in a proportion of 1 to 10% by mass based on the total amount of the composition. The lower limit of the above blending amount is more preferably 2% by mass, still more preferably 2.5% by mass, and particularly preferably 3% by mass. The upper limit of the above blending amount is more preferably 7% by mass, still more preferably 5% by mass. When a polyisocyanate compound is used as the above hardener, the content of the polyisocyanate compound is preferably 0.1 to 5 equivalents in terms of NCO / OH with respect to 1 equivalent of the hydroxyl group in the fluorine-containing copolymer (B), and more preferably 0.5 to 1.5 equivalents in terms of NCO / OH.

[0046] (Curing catalyst) When using the above curing agent, a curing catalyst may be used depending on the type of curing agent used.

[0047] (Pigments) The pigments that can be used in the compositions of this disclosure are not particularly limited, and examples include titanium dioxide, complex iron oxides, extender pigments, organic pigments, ceramic pigments, and dyes.

[0048] The composition of this disclosure preferably contains the above pigment in a proportion of 0 to 300% by mass relative to the fluorine-containing copolymer (B). The lower limit of the above amount is more preferably 5% by mass, and even more preferably 10% by mass. The upper limit of the above amount is more preferably 200% by mass, and even more preferably 150% by mass.

[0049] The composition of this disclosure preferably has a viscosity of less than 100 mPa·s at a resin content of 21% by mass, more preferably less than 40 mPa·s. At a resin content of 50% by mass, the viscosity is preferably less than 4000 mPa·s, more preferably less than 2000 mPa·s, and particularly preferably less than 1000 mPa·s. The viscosity can be measured, for example, using a Type B rotational viscometer (manufactured by Toki Sangyo) at a measurement temperature of 25°C.

[0050] (Manufacturing Method) The compositions of this disclosure do not particularly limit the method of manufacturing them and can be obtained by a general method of mixing the components constituting the composition.

[0051] The composition of this disclosure may be prepared by mixing the solvent (A) and the fluorine-containing polymer (B) at the site where painting is performed, while in the distribution stage such as during storage and transport.

[0052] (Composition for Paints) The compositions of the present disclosure can be used as compositions for paints. When used as a composition for paints, the painting method is not particularly limited and examples include air spray painting, airless spray painting, rotary atomization painting, curtain coat painting, etc., among which air spray painting, rotary atomization painting, etc. are preferred. The content of the composition of the present disclosure in the paint composition may be 90% by mass or more, 95% by mass or more, or 100% by mass. In addition to the composition of the present disclosure, the paint composition may further contain at least one selected from the group consisting of, for example, acrylic resin, urethane resin, melamine resin, urea resin, diol resin (for example, polycarbonate diol, etc.), and epoxy resin.

[0053] The coating compositions of this disclosure may be used in combination with other coating compositions to form a multi-layer coating film.

[0054] (Uses) The paint composition disclosed herein is not particularly limited in its uses, but can be suitably used as a heavy-duty anticorrosive paint in the construction industry, for example, for bridges, steel towers, and high-rise buildings. Furthermore, it can be used as a paint for building materials such as metal building materials, for printing, for inks, etc., and the substrate is not particularly limited, and can be used for painting metals (iron, copper, aluminum, etc.), concrete, wood, plastics, paper, etc. The articles disclosed herein are painted with the above composition. Examples of articles disclosed herein include buildings (bridges, steel towers, high-rise buildings, etc.), metals (iron, copper, aluminum, etc.), concrete, wood, plastics, paper, etc., painted with the above composition.

[0055] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims.

[0056] The present disclosure will now be described in detail based on the following examples. In the following examples, unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass," respectively.

[0057] The polymers used in the following examples are as follows. Polymerization was carried out by the following method.

[0058] (Production Example 1: Fluorine-containing copolymer solid B-1) 2500 g of butyl acetate, 860 g of vinyl neononanoate (Veova9), 215 g of 4-hydroxybutyl vinyl ether (HBVE), and 7.4 g of crotonic acid (CTA) were added to a 6000 ml stainless steel autoclave. The autoclave was then subjected to reduced pressure nitrogen purging, and 590 g of tetrafluoroethylene (TFE) was added. The temperature was raised to 60.0°C under stirring, and 30 g of peroxide-based polymerization initiator was added to start polymerization. The reaction was stopped when the reactor pressure decreased from 1.0 MPaG to 0.4 MPaG, and solution B-1 containing polymer with TFE / HBVE / vinyl neononanoate / CTA = 45.5 / 15.3 / 37.9 / 1.3 mol% was obtained. The obtained solution was dried in a thin-film dryer to remove the butyl acetate, and the solid B-1 was recovered. Solid material B-1 was finely chopped to facilitate dissolution in the solvent. The recovered solid material B-1 had a heating residue of 99.2%.

[0059] (Production Example 2: Fluorine-containing copolymer solid B-2) Solid B-2 was produced in the same manner as in Production Example 1, except that the peroxide-based polymerization initiator was changed to 60 g. The heating residue of the recovered solid B-2 was 99.1%. (Production Example 3: Fluorine-containing copolymer solid B-3) A solution containing a polymer with the ratio chlorotrifluoroethylene (CTFE) / cyclohexyl vinyl ether (CHVE) / ethyl vinyl ether (EVE) / 2-hydroxyethyl vinyl ether (HBVE) = 48.4 / 9.5 / 32.9 / 9.2 mol% was obtained in the same manner as in Production Example 1. The obtained solution was subjected to a thin film dryer to remove butyl acetate and solid B-3 was recovered. The solid was finely chopped to make it easily soluble in the solvent. The heating residue of the recovered solid B-3 was 99.5%.

[0060]

[0061] TFE: Tetrafluoroethylene CTFE: Chlorotrifluoroethylene Veova9 (trade name): Vinyl neononanoate CHVE: Cyclohexyl vinyl ether EVE: Ethyl vinyl ether HBVE: 4-Hydroxybutyl vinyl ether CTA: Crotonic acid

[0062] The boiling points of each solvent used in the examples are shown below. t-BAC: t-butylacetic acid (boiling point 98°C) PCBTF: parachlorobenzotrifluoride (boiling point 139°C) Acetone (boiling point 56°C) Dimethyl carbonate (boiling point 90°C)

[0063] The items listed in Table 1 were analyzed using the following method: (Analysis of monomer unit content constituting the copolymer) Elemental analysis was performed on the fluororesin composition, and the measured fluorine content (mass%) was determined. １ H-NMR, １９ The content (mol%) of each monomer unit was calculated from compositional analysis using F-NMR spectroscopy.

[0064] (Weight-average molecular weight) Measuring device: GPC (Model: HLC-8420) manufactured by Tosoh Corporation. Measurement conditions: Three TSKgel SuperMultiporeHZ-M columns were used. Tetrahydrofuran was used as the eluent, and polystyrene with a known molecular weight was used as the standard sample for molecular weight.

[0065] (Hydroxyl Value) The hydroxyl value (unit: mgKOH / g) was calculated from the above content analysis results of the fluororesin composition using formula (1). Hydroxyl value = {[OH (mass%)] / 100} / [OH (equivalent)] × [KOH molecular weight] × 1000 ... (1) In formula (1), the "KOH molecular weight" is 56.1. In formula (1), "OH (mass%)" represents the weight ratio (unit: mass%) of all hydroxyl group-containing monomers to all monomers, calculated from the content (unit: mol%) of each monomer unit calculated in the above content analysis. In formula (1), "OH (equivalent)" represents the value calculated from formula (2). [OH (equivalent)] = [Molecular weight of hydroxyl group-containing monomer] / [Number of hydroxyl groups in one molecule of hydroxyl group-containing monomer] ... (2)

[0066] (Acid value) Measured by potentiometric titration in accordance with JIS K 5601.

[0067] (Heating residue) 2g in an aluminum cup (initial mass W) ０ The fluororesin solids of ) were weighed and heated in an electric furnace at 150°C for 1 hour, and the remaining mass (W) was obtained. １ ) From the fluororesin composition, the heat residue (unit: mass%, heat residue = 100 × residue mass W) １ / Initial mass W ０ ) was calculated.

[0068] (Examples 1-5 and Comparative Examples 1-3) Compositions were prepared by mixing each component in the proportions shown in Table 2. The values ​​in the table are in mass percent. Each composition was evaluated using the following method. The results are shown in Table 2.

[0069] (Resin Solubility) When 100g of polymer was dissolved in 100g of solvent at 23°C, the dissolution was evaluated as ○ (good) and the dissolution was evaluated as × (poor). The solvents used were those listed in Table 2 in the formulations listed in Table 2.

[0070] (White paint production) When preparing a paint containing titanium dioxide, a good result (○) was given if the titanium dioxide was well dispersed and a uniform composition was obtained, and a bad result (×) was given if the paint could not be obtained because the titanium dioxide was not dispersed.

[0071] (Paintability) Using an air spray gun (Wider W101, 1.3 mm nozzle diameter, manufactured by Anest Iwata), discharge pressure 3 kgf / cm² ２ Then, 100g of paint mixed with a hardener is applied to 1m ２ The paint was applied to the substrate. When the resulting paint was spray-applied to the substrate, samples that formed a paint film without any problems were marked with ○ (good), samples that were painted but uneven were marked with △ (average), and samples that did not form a paint film during spraying were marked with × (poor). The substrate used was an aluminum plate (Paltec Co., Ltd., A1050P, AM713 treated plate, 0.8 mm thick).

[0072] (Gloss) For the coating film obtained by the above-mentioned paintability, the gloss at 60 degrees was measured using a gloss meter (manufactured by Konica Minolta) conforming to the mirror glossiness of JIS K5600 4-7. When the gloss was 75 or more, it was marked as ○ (good), and when the gloss was less than 75, it was marked as × (bad).

[0073] (Pencil hardness) For the coating film obtained by the above-mentioned paintability, a test conforming to the scratch hardness (pencil method) of JIS K5600-5-4 was conducted. Mitsubishi Uni pencils were used. The hardness of the hardest pencil that did not cause scratches was defined as the pencil hardness. When the pencil hardness was B or more, it was marked as ○ (good), and when the pencil hardness was less than B, it was marked as × (bad).

[0074] (Weather resistance) The test was conducted by the accelerated weather resistance (ultraviolet fluorescent lamp method, the lamp is UV-B). An accelerated weather resistance test was conducted on the sample with the following conditions as one cycle. (i) Irradiation (black panel temperature: 60 °C, illuminance: 0.63 W / m ２ ): 4 hours (ii) Dark and dew condensation (tank temperature: 50 °C): 4 hours The gloss retention rate = gloss after 1000 hours / initial gloss × 100 was calculated from the initial gloss and the gloss after 1000 hours. Evaluation was conducted based on the criterion that the gloss retention rate was 80% or more as ○ (good) and less than 80% as × (bad).

[0075] (Solvent resistance) Methyl ethyl ketone was impregnated into Benkot (manufactured by Otsu Sangyo Co., Ltd.), and a load of 1 kg was applied on the coating film, and it was rubbed 100 times back and forth. Evaluation was conducted such that when the coating film did not dissolve, it was marked as ○ (good), and when the coating film dissolved, it was marked as × (bad).

[0076] (Viscosity) The rotational viscosity of the solution at a temperature of 25°C was measured using a Type B rotational viscometer (manufactured by Toki Sangyo Co., Ltd.). For the viscosity of the measurement sample with a resin content of 21% in the composition, ○ (low viscosity) was used if it was less than 40 mPa·s, △ (medium viscosity) if it was 40 mPa·s or more and less than 80 Pa·s, and × (high viscosity) if it was 80 Pa·s or more. For the viscosity of the measurement sample with a resin content of 50% in the composition, ○ (low viscosity) was used if it was less than 2000 mPa·s, △ (medium viscosity) if it was 2000 mPa·s or more and less than 5000 Pa·s, and × (high viscosity) if it was 5000 Pa·s or more. The measurement sample with a "resin content of 21% in the composition" was measured using the composition shown in Table 3, and the measurement sample with a "resin content of 50% in the composition" was measured using the composition shown in Table 4. In Tables 3 and 4, the unit of blending amount is parts by mass.

[0077]

[0078]

[0079]

[0080] The results in Table 2 clearly show that the compositions of this disclosure have good weather resistance and solvent resistance.

[0081] The compositions of this disclosure can be suitably used as coating compositions in fields where weather resistance and other properties are required.

Claims

1. A composition comprising a solvent (A) and a fluorine-containing copolymer (B), wherein the solvent (A) is parachlorobenzotrifluoride (a1), or a mixed solvent of parachlorobenzotrifluoride (a1) and a solvent (a2) having a boiling point of 100°C or less, the ratio (mass ratio) of (a1) / (a2) in the solvent (A) is 50 / 50 to 100 / 0 (excluding 50 / 50), and the fluorine-containing copolymer (B) comprises structural units (b1) derived from fluoroolefins and structural units (b2) derived from at least one selected from the group consisting of vinyl esters, vinyl ethers, allyl ethers, and hydroxyl group-containing unsaturated compounds.

2. The composition according to claim 1, wherein the solvent (a2) having a boiling point of 100°C or less is at least one selected from the group consisting of t-butylacetic acid, dimethyl carbonate, methyl acetate, and acetone.

3. The composition according to claim 1 or 2, wherein the mass ratio (B) / (A) of the fluorine-containing copolymer (B) to the solvent (A) is 75 / 25 to 10 / 90.

4. The composition according to any one of claims 1 to 3, wherein the structural unit (b1) derived from the fluoroolefin is a structural unit selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene.

5. The composition according to any one of claims 1 to 4, wherein the structural unit (b1) derived from the fluoroolefin is a structural unit derived from tetrafluoroethylene.

6. The composition according to any one of claims 1 to 5, wherein the structural unit (b2) is a structural unit derived from vinyl ester.

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

8. The composition according to any one of claims 1 to 7, wherein the solvent (a2) having a boiling point of 100°C or less is an organic solvent having a boiling point of 80°C or more and 100°C or less, the mass ratio (B) / (A) of the fluorine-containing copolymer (B) to the solvent (A) is 35 / 65 to 15 / 85, the structural unit (b1) derived from the fluoroolefin is a structural unit selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene, and the structural unit (b2) is a structural unit derived from at least one selected from the group consisting of hydroxyl-free vinyl esters and hydroxyl-free vinyl ethers, and a structural unit derived from a hydroxyl-containing vinyl ether.

9. A paint composition characterized by comprising the composition described in any one of claims 1 to 8.

10. An article characterized by being coated with the composition described in any one of claims 1 to 8.

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