JP2019011470A - Powder coating, method for producing powder coating, method for producing base material with coating film, and base material with coating film - Google Patents

Abstract

To provide a powder coating that can form a coating film having excellent interlayer adhesion, a method for producing a powder coating, a method for producing a base material with a coating film, and a base material with a coating film.SOLUTION: A powder coating contains a fluorine-containing modified polymer that has a unit having a polyester chain and a unit based on fluoroolefin in a side chain, the fluorine-containing modified polymer having a hydroxyl value or an acid value of 1-200 mgKOH/g.SELECTED DRAWING: None

Description

  The present invention relates to a powder coating containing a fluorine-containing modified polymer, a method for producing a powder coating, a method for producing a substrate with a coating film, and a substrate with a coating film.

  Powder coatings are attracting attention from the viewpoint of reducing environmental impact, and are required to be used for various applications. Patent Document 1 discloses a powder coating containing fluoropolymer particles and polyester particles obtained by melt-kneading a fluoropolymer and polyester, followed by cooling and pulverization.

International Publication No. 2013/186832

  The inventors of the present invention have obtained a coating film obtained by using the powder coating material described in Patent Document 1, in which the fluoropolymer layer and the polyester layer are peeled off and the interlayer adhesion of the coating film is reduced. I found out that it might be inferior.

  In view of the above problems, the present invention provides a powder coating material capable of forming a coating film excellent in interlayer adhesion, a method for manufacturing a powder coating material, a method for manufacturing a substrate with a coating film, and a substrate with a coating film Let it be an issue.

As a result of intensive studies on the above problems, the present inventors have found a fluorine-containing modified polymer having a predetermined hydroxyl value or a predetermined acid value, which includes a unit based on a fluoroolefin and a unit having a polyester chain in a side chain. It has been found that a coating film excellent in interlayer adhesion can be obtained by using the powder coating material, and has led to the present invention.
That is, the present inventor has found that the above problem can be solved by the following configuration.

[1] A fluorine-containing modified polymer containing a unit having a polyester chain in a side chain and a unit based on a fluoroolefin, the hydroxyl group value or acid value being 1 to 200 mgKOH / g. Powder paint characterized by.
[2] The unit having the polyester chain in the side chain includes the side chain functional group of a unit having at least one side chain functional group among the hydroxyl group and carboxy group, and at least one terminal group of the hydroxyl group and carboxy group. The powder coating material according to [1], wherein the terminal group of the polyester having is a unit having an ester bond.
[3] The unit having the polyester chain in the side chain is a side chain functional group of a unit having at least one side chain functional group among a hydroxyl group and a carboxy group, a polyvalent carboxylic acid, and a polyhydric alcohol. The powder coating material according to [1], which is a unit of a structure obtained by dehydration condensation polymerization.
[4] The powder coating material according to any one of [1] to [3], wherein the unit having a polyester chain in the side chain is a unit represented by the following formula (P1).
The symbols in the formula have the following meanings.
R ¹ and R ² are each independently a hydrogen atom or a methyl group.
L is a group derived from a side chain in a unit based on the monomer having the side chain functional group.
A is a polyester chain.
Z is a hydroxyl group or a carboxy group.

[5] The hydroxyl value of the fluorine-containing modified polymer is 10 to 150 mgKOH / g, or the acid value of the fluorine-containing modified polymer is 5 to 150 mgKOH / g. The powder coating material in any one.
[6] The fluorine-containing modified polymer has a hydroxyl group and a carboxy group, the hydroxyl value is 10 to 150 mgKOH / g, and the acid value is 5 to 150 mgKOH / g. [1] to [5] The powder coating according to any one of the above.
[7] The powder coating material according to any one of [1] to [6], wherein the fluorine-containing modified polymer has a glass transition temperature of 45 to 120 ° C.
[8] The content of the unit having the polyester chain in the side chain is 1 to 40 mol% with respect to all units of the fluorine-containing modified polymer, according to any one of [1] to [7]. Powder paint.
[9] The powder according to any one of [1] to [8], wherein the ratio of the mass of the polyester chain to the mass of the fluorine-containing modified polymer excluding the polyester chain is 2.0 to 9.0. Body paint.
[10] The powder coating material according to any one of [1] to [9], including a curing agent.

[11] A method for producing a powder coating material according to any one of [1] to [10],
A fluorine-containing polymer comprising a unit having at least one side chain functional group among a hydroxyl group and a carboxy group and a unit based on a fluoroolefin is reacted with a polyester having at least one terminal group among the hydroxyl group and the carboxy group. A solid fluorine-containing modified polymer is obtained, and then the fluorine-containing modified polymer is pulverized.
[12] The production method according to [11], wherein the ratio of the mass of the polyester to the mass of the fluoropolymer is 2.0 to 9.0.
[13] The production method according to [11] or [12], wherein the reaction is performed in the presence of a condensing agent.
[14] The method for producing a powder coating material according to any one of [1] to [10],
By reacting a fluorine-containing polymer, a polyvalent carboxylic acid and a polyhydric alcohol containing a unit having at least one side-chain functional group among a hydroxyl group and a carboxy group with a unit based on a fluoroolefin, a solid fluorine-containing modified polymer is obtained. A method for producing a powder coating material comprising obtaining a coalescence and then pulverizing the fluorine-containing modified polymer.
[15] The production method according to [14], wherein a ratio of a total mass of the polyvalent carboxylic acid and the polyhydric alcohol to a mass of the fluoropolymer is 2.0 to 9.0.

[16] The powder coating material according to any one of [1] to [10] is applied on a substrate to form a coating layer, and the coating layer is heat-treated to form a coating film on the substrate. A method for producing a base material with a coating film, characterized in that it is formed.
[17] A base material with a coating film, comprising: a base material; and a coating film formed on the base material with the powder coating material according to any one of [1] to [10].

  As shown below, according to the present invention, a powder coating material capable of forming a coating film excellent in interlayer adhesion, a method for producing a powder coating material, a method for producing a substrate with a coating film, and a substrate with a coating film Can provide.

The meanings of terms in the present invention are as follows.
The “unit” is a general term for an atomic group derived from one molecule of the monomer, in which the monomer is directly formed by polymerization, and an atomic group obtained by chemically converting a part of the atomic group. . Hereinafter, the “unit based on monomer” is also simply referred to as “unit”. The content (mol%) of each unit with respect to all the units contained in the polymer is obtained by analyzing the polymer by nuclear magnetic resonance spectroscopy, and also from the charged amounts of the components used in the production of the polymer. I can guess.
The “average particle size” of the particles is calculated by calculating the volume average from the particle size distribution measured using a known particle size distribution measuring apparatus (manufactured by Sympatec, trade name “Helos-Rodos”, etc.) based on the laser diffraction method. Thus, the 50% diameter value is obtained.
The “acid value” and “hydroxyl value” are values measured according to the method of JIS K 0070-3 (1992), respectively.
“Glass transition temperature” is a midpoint glass transition temperature measured by a differential scanning calorimetry (DSC) method. “Glass transition temperature” is also referred to as “Tg”.
“Number average molecular weight” and “weight average molecular weight” are values measured by gel permeation chromatography using polystyrene as a standard substance. “Number average molecular weight” is also referred to as “Mn”, and “weight average molecular weight” is also referred to as “Mw”.

The powder coating material of the present invention is a powder coating material including a fluorine-containing modified polymer including a unit having a polyester chain in a side chain (hereinafter also referred to as “unit P”) and a unit based on a fluoroolefin. The hydroxyl group value or acid value of the fluorine-containing modified polymer is 1 to 200 mgKOH / g. Such a fluorine-containing modified polymer is hereinafter also referred to as “modified polymer”.
The unit P of the modified polymer is a unit having at least one side chain functional group (hereinafter also referred to as “unit 1”) of a hydroxyl group and a carboxy group and a unit based on a fluoroolefin (hereinafter also referred to as “unit F”). And the above-mentioned side chain functional group of a fluorine-containing polymer (hereinafter also referred to as “specific fluorine-containing polymer”), and the terminal group of the polyester having at least one terminal group among a hydroxyl group and a carboxy group; Is preferably a unit having an ester-bonded structure.
The unit P of the modified polymer is also preferably a unit having a structure obtained by dehydration condensation polymerization of the unit 1 of the specific fluoropolymer, the polyvalent carboxylic acid, and the polyhydric alcohol.

The content of the unit P contained in the modified polymer may be different between the molecules of the modified polymer. Specifically, the modified polymer is composed of a polymer in which the side chain functional group of unit 1 and the terminal group of the polyester are highly ester-bonded to form unit P, the side chain functional group of unit 1 and the polyester. It may be a mixture with a polymer in which the terminal group has a low ester bond to form unit P. Furthermore, the polyester chain of the unit P may be different between the molecules of the modified polymer. Specifically, the modified polymer may have a polyester chain in which the end groups of the polyester are highly linked. The polyester terminal group may have a polyester chain in which the end groups are connected to each other at a low degree, or a mixture of these polymers. That is, the content of the unit P and the polyester chain of the modified polymer in the present invention may be different among the molecules of the modified polymer, and are usually different.
In addition, the level of the ester bond with the side chain functional group of the unit 1 mentioned above and the terminal group of polyester refers to the level of the ratio of the ester terminal group of the polyester with respect to the total number of side chain functional groups of the unit 1. Moreover, the level of the connection between the terminal groups of the polyester described above and the level of the connection of the polyester chain described later indicate the degree of polymerization of the polyvalent carboxylic acid residue and the polyhydric alcohol residue in the polyester chain.

Generally, a coating film formed from a powder coating material containing fluoropolymer particles and polyester particles has a two-layer structure in which the fluoropolymer is disposed on the air side and the polyester is disposed on the substrate side. . In the two-layer structure, the layer containing the fluoropolymer protects the layer containing the polyester, and thus exhibits high weather resistance. However, in the coating film, there is a tendency that the interlayer adhesion between the layer containing the fluoropolymer and the layer containing the polyester tends to be inferior, and the weather resistance may be impaired due to peeling between the layers. They found out.
The coating film formed by the powder coating material of the present invention (hereinafter also referred to as “the present coating film”) is a polymer molecule having a high fluorine content among modified polymers (in other words, connected to a low degree). Modified polymer molecules having a polyester chain.) Segregated on the air side, polymer molecules having a low fluorine content (in other words, modified polymer molecules having a highly linked polyester chain) segregated on the substrate side. It is thought to be a coating composition. That is, it can be said that a pseudo two-layer structure in which a concentration gradient of fluorine content occurs in the coating film is formed. Therefore, this coating film used the coating film of the conventional 2 layer structure, expressing the high weather resistance which the coating film of the 2 layer structure of the layer containing the conventional fluoropolymer and the layer containing polyester has. Delamination that was a problem at the time is difficult to occur. Therefore, according to the powder coating material of this invention, it is thought that the coating film excellent in interlayer adhesiveness can be formed, maintaining a high weather resistance.
In addition, the powder coating is required to have blocking resistance. The blocking resistance of the powder coating can be improved by using, for example, a fluorine-containing polymer having a high Tg. Therefore, it is necessary to select a component that improves Tg as a unit contained in the fluorine-containing polymer. On the other hand, the Tg of the modified polymer can be adjusted to a high level by introducing a bulky polyester chain. That is, in the production of the powder coating material of the present invention, there is an advantage that the degree of freedom in selecting the monomer used for the introduction of other units is high even when other units are to be introduced into the modified polymer.

The modified polymer has at least one of a hydroxyl group and a carboxy group, and more preferably has both of them.
In the modified polymer, at least one of the hydroxyl value and the acid value may be 1 to 200 mgKOH / g, and both the hydroxyl value and the acid value may be 1 to 200 mgKOH / g.
The acid value of the modified polymer is preferably from 5 to 150 mgKOH / g, particularly preferably from 20 to 60 mgKOH / g. Moreover, 10-150 mgKOH / g is preferable and, as for the hydroxyl value of a modified polymer, 20-60 mgKOH / g is especially preferable.
The modified polymer having a hydroxyl group and a carboxy group preferably has a hydroxyl value of 5 to 150 mgKOH / g and an acid value of 10 to 150 mgKOH / g, and a hydroxyl value of 20 to 60 mgKOH / g. And it is especially preferable that the acid value is 20-60 mgKOH / g.
If the acid value or hydroxyl value of the modified polymer is within the above range, the adhesion of the coating film to the substrate is improved and the powder coating containing the modified polymer is suitably melted to form a dense coating film. it can.
The hydroxyl group or carboxy group of the modified polymer is derived only from the side chain end of the unit P, or from the side chain end of the unit P and the unit 1 unreacted with the polyester.
That is, the following two aspects are mentioned as a specific example of the aspect which the modified polymer in this invention can take.
1st aspect: A modified polymer contains the unit F, the unit P, and the unit 1, at least 1 type of terminal group among the hydroxyl groups and carboxy groups of the unit P, and at least 1 type of side chain among the hydroxyl groups or carboxy groups of the unit 1 And an embodiment having a functional group.
Second aspect: An aspect in which the modified polymer contains unit F and unit P, does not contain unit 1, and has at least one terminal group among the hydroxyl group and carboxy group of unit P.
Here, since the hydroxyl group and carboxy group of unit 1 and the hydroxyl group or carboxy group of unit P can all serve as a cross-linking point when forming the coating film, the curability of the coating film can be improved. The first aspect of the fluoropolymer of the present invention is preferably the above-described two aspects from the viewpoint of further improving the curability of the coating film.

The unit P is a unit having a polyester chain in the side chain. The unit P preferably has no fluorine atom.
The unit P may be a unit in which the hydroxyl group or carboxy group of the unit 1 and the terminal group of the polyester are ester-bonded. The unit P is preferably a unit in which the hydroxyl group or carboxy group of the unit 1 and the terminal group of the polyester are directly ester-bonded. The unit P is preferably a unit in which the hydroxyl group of the unit 1 and the carboxy group of the polyester are directly ester-bonded, or a unit in which the carboxy group of the unit 1 and the hydroxyl group of the polyester are directly ester-bonded.
The polyester chain preferably includes a unit based on a dehydration reaction product of a polyvalent carboxylic acid and a polyhydric alcohol, and may include other units (for example, a unit based on a hydroxycarboxylic acid) as necessary. Good.
The polyester chain may be a chain obtained by a transesterification reaction. The polyester chain may be a chain generated by ring-opening polymerization of lactone or the like.
Specific examples of the polyvalent carboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, trimellitic acid, pyromellitic acid, phthalic anhydride, and other aromatic polyvalent carboxylic acids, as well as succinic acid and adipine. Non-aromatic polyvalent carboxylic acids such as acid, sebacic acid, succinic anhydride and the like can be mentioned. The non-aromatic polycarboxylic acid means a polyvalent carboxylic acid having no aromatic ring.
Specific examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,2- Aliphatic polyvalents such as pentanediol, 1,5-pentanediol, neopentylglycol, spiroglycol, 1,10-decanediol, 1,4-cyclohexanedimethanol, trimethylolethane, trimethylolpropane, glycerin, pentaerythritol Examples thereof include alicyclic polyhydric alcohols such as alcohol, 1,4-cyclohexanedimethanol and 1,4-cyclohexanediol.
When the polyester chain is produced by a transesterification reaction, an ester such as dimethyl terephthalate or biphenylmethyldicarboxylate may be used to transesterify with a polyhydric alcohol.
When the polyester chain is a chain produced by ring-opening polymerization such as lactone, lactones include β-propiolactone, δ-valerolactone, ε-caprolactone, methyl-ε-caprolactone, α-methyl-β-pro Examples include piolactone, β-methyl-β-propiolactone, methoxy-ε-caprolactone, ethoxy-ε-caprolactone, and the like.

  The unit P is preferably a unit represented by the following formula (P1) from the viewpoint of production.

The symbols in the formula have the following meanings.
R ¹ and R ² are each independently a hydrogen atom or a methyl group.
L is a group derived from the side chain in unit 1.
A is a polyester chain.
Z is a hydroxyl group or a carboxy group.

  The unit represented by the formula (P1) is preferably a unit represented by the following formula (P1-1) or a unit represented by the following formula (P1-2) from the viewpoint of production.

The symbols in the formula have the following meanings.
R ^{1, R} 2, Z are each the same meaning as ^{R 1, R} 2, Z of formula (P1).
A ¹ and A ² are both polyester chains.
L ¹ and L ² are residues of a group derived from the side chain in unit 1. That is, L ¹ is a residue obtained by removing the carboxy group at the end from the side chain in the unit 1, and L ² is a residue obtained by removing the hydroxyl group at the end from the side chain in the unit 1. However, when the side chain of unit 1 consists only of a hydroxyl group or a carboxy group, L ¹ and L ² are a single bond.

When the polyester chain is a chain of a dehydration polycondensation product of a diol represented by HO—A ¹¹ —OH and a dicarboxylic acid represented by H—OC (O) —A ¹² —C (O) OH,
-A ¹ -Z ^{is, - (A 11 -OC (O} ) -A 12 -C (O) O) n1 -A 11 -OH ^{or,, - (A 11 -OC (} O) -A 12 -C ( _O) ^O) is preferably a group having a polyester chain represented by ^{n1 -A 11 -OC (O) -A} 12 -COOH.
Further, ^-A 2 -Z ^{is, - (A 12 -C (O} ) O-A 11 -OC (O)) n2 -A 12 -COOH ^{or,, - (A 12 -C (} O) O-A 11 -OC ^_(O)) is preferably n2 -A 12 -C ^(O) group having a polyester chain represented by ^O-a 11 -OH.
In the formula, A ¹¹ and A ¹² are each independently a divalent organic group. Examples of the divalent organic group include an alkylene group, a cycloalkylene group, an arylene group, an aralkylene group, and a group obtained by combining these. The alkylene group may be linear or branched. A plurality of A ¹¹ present in the formula may be different types of A ¹¹ , and a plurality of A ¹² present in the formula may also be different types of A ¹² .
n1 and n2 are average values and represent an integer of 2 or more, and the upper limit is not particularly limited and is usually 100.

Specific examples of L ¹ and L ² include — (CH ₂ ) _a — (wherein a represents an integer of 1 to 10), —O—CH ₂ -cycloC ₆ H ₁₀ —CH ₂ —, —CH. ₂ O—CH ₂ -cycloC ₆ H ₁₀ —CH ₂ —, —OCH ₂ CH ₂ —, —CH ₂ OCH ₂ CH ₂ —, —OCH ₂ CH ₂ CH ₂ CH ₂ —, —CH ₂ OCH ₂ CH ₂ CH ₂ CH ₂ —, —O (CH ₂ ) _b —OC (O) — (CH ₂ ) _c —. However, b and c show the integer of 1-10 each independently.

The modified polymer may contain two or more units P.
The content of the unit P is more than 0 mol% with respect to the total units included in the modified polymer, and is equal to or less than the content of the unit 1 with respect to the total units included in the specific fluoropolymer. The content of the unit P is preferably 1 to 40 mol%, more preferably 1 to 25 mol%, and more preferably 3 to 23 mol% from the viewpoint of improving interlayer adhesion with respect to all units contained in the modified polymer. Is more preferable, and 5 to 20 mol% is particularly preferable.
Further, the ratio of the mass of the polyester chain to the mass of the modified polymer excluding the polyester chain in the modified polymer is from the viewpoint of the weather resistance of the present coating film and the concentration gradient of fluorine content in the present coating film, 0.01-20 are preferable, 0.1-9 are more preferable, 2.0-9.0 are further more preferable, and 2.0-5.0 are especially preferable.
The mass of the modified polymer excluding the polyester chain corresponds to the mass of the specific fluoropolymer, and the mass of the polyester chain is the mass of the introduced polyester chain (including the terminal group represented by Z). It is.

The unit 1 is a unit having at least one side chain functional group among a hydroxyl group and a carboxy group. Unit 1 does not have a polyester chain. Unit 1 preferably has no fluorine atom.
Unit 1 may be a unit based on a monomer having the above-mentioned side chain functional group (hereinafter also referred to as “monomer 1”), and the above side chain of the specific fluoropolymer containing unit 1 It may be a unit obtained by converting a functional group into a different side chain functional group. Examples of such units include units in which a part or all of hydroxyl groups are converted to carboxy groups by reacting a specific fluorinated polymer containing units having hydroxyl groups with a polyvalent carboxylic acid or an acid anhydride thereof. Is mentioned.
The unit 1 is preferably a unit based on the monomer 1.

Examples of the monomer 1 having a carboxy group include unsaturated carboxylic acid and (meth) acrylic acid. The monomer represented by the formula X ¹¹ -Y ¹¹ (hereinafter also referred to as “monomer 11”). ) Is preferred.
X ¹¹ is CH ₂ ═CH—, CH (CH ₃ ) ═CH— or CH ₂ ═C (CH ₃ ) —, and preferably CH ₂ ═CH— or CH (CH ₃ ) ═CH—. .
Y ¹¹ is a C 1-12 monovalent saturated hydrocarbon group having a carboxy group or a carboxy group, and is preferably a carboxy group or a C 1-10 carboxyalkyl group.
Specific examples of the monomer 11 include compounds represented by CH ₂ ═CHCOOH, CH (CH ₃ ) ═CHCOOH, CH ₂ ═C (CH ₃ ) COOH and the formula CH ₂ ═CH (CH ₂ ) _m1 COOH ( However, m1 shows the integer of 1-10.).

Examples of the monomer 2 having a hydroxy group include a vinyl group, vinyl ether, vinyl ester, allyl ether, allyl ester, (meth) acrylic acid ester, and allyl alcohol having a hydroxy group, which are represented by the formula X ¹² -Y ^12. Monomer (hereinafter also referred to as “monomer 12”) or allyl alcohol is preferred.
X ¹² _{is, CH 2 = CHC (O)} O-, CH 2 = C (CH 3) C (O) O-, CH 2 = CHOC (O) -, CH 2 = CHCH 2 OC (O) -, CH ₂ = CHO- or _CH 2 = CHCH ₂ is _O-, CH 2 = CHO- or preferably _{CH 2} = CHCH 2 O- in which.
Y ¹² is a monovalent saturated hydrocarbon group having 2 to 12 carbon atoms having a hydroxyl group. The monovalent saturated hydrocarbon group may be linear or branched. Moreover, the monovalent saturated hydrocarbon group may consist of a ring structure or may contain a ring structure.
The monovalent saturated hydrocarbon group is preferably an alkyl group containing an alkyl group having 2 to 6 carbon atoms or a cycloalkylene group having 6 to 8 carbon atoms.
Specific examples of the monomer _{12, CH 2 = CHOCH 2 -cycloC} 6 H 10 -CH 2 OH, CH 2 = CHCH 2 O-CH 2 -cycloC 6 H 10 -CH 2 OH, CH 2 = CHOCH _{2 CH 2 OH, CH 2 =} CHCH 2 OCH 2 CH 2 OH, CH 2 = CHOCH 2 CH 2 CH 2 CH 2 OH, and _{CH 2 = CHCH 2 OCH 2 CH} 2 CH 2 CH 2 OH and the like.
Monomer 1 may use 2 or more types together.

When the powder coating contains a curing agent, the hydroxyl group or carboxy group of unit 1 or the hydroxyl group or carboxy group of unit P becomes a crosslinking point, and the crosslinking reaction between the modified polymers proceeds via the curing agent. Since the sclerosis | hardenability of a coating film improves, the coating-film physical properties, such as the weather resistance, water resistance, chemical resistance, and heat resistance, improve.
When the modified polymer contains unit 1, the content of unit 1 is preferably 1 to 35 mol%, more preferably 1 to 25 mol%, and more preferably 3 to 23 mol%, based on all units contained in the modified polymer. Is more preferable, and 5 to 20 mol% is particularly preferable.

A fluoroolefin is an olefin in which one or more hydrogen atoms are substituted with fluorine atoms. In the fluoroolefin, one or more hydrogen atoms not substituted with fluorine atoms may be substituted with chlorine atoms.
Specific examples of fluoroolefins include CF ₂ = CF ₂ , CF ₂ = CFCl, CF ₂ = CHF, CH ₂ = CF ₂ , CF ₂ = CFCF ₃ , CF ₂ = CHCF ₃ , CF ₃ CH = CHF, CF ₃ CF = CH ₂ and the like. From the viewpoint of efficiently forming the unit P, it is preferable to use CF ₂ = CF ₂ or CF ₂ = CFCl as the fluoroolefin, and it is particularly preferable to use CF ₂ = CFCl. Two or more fluoroolefins may be used in combination.
Content of the unit F is 20-70 mol% with respect to all the units which a modified polymer contains from a weather resistance viewpoint of this coating film, and 40-60 mol% is preferable.

The modified polymer is a unit based on a monomer represented by the formula X ² -Z ² (hereinafter also referred to as “monomer 2”) in order to adjust the coating film properties of the coating film (hereinafter referred to as “monomer 2”). "Unit 2") may be included. It is preferable that the monomer 2 does not have a fluorine atom.
X ² represents CH ₂ ═CHC (O) O—, CH ₂ ═C (CH ₃ ) C (O) O—, CH ₂ ═CHOC (O) —, CH ₂ ═CHCH ₂ OC (O) —, CH ₂ = CHO- or _CH 2 = CHCH ₂ is O-, from the viewpoint of weather resistance of the coating _{film, CH 2 = CHOC (O)} -, CH 2 = CHCH 2 OC (O) -, CH 2 = CHO- or _{CH 2} = CHCH 2 O- are preferred.

Z ² is a monovalent hydrocarbon group having 1 to 24 carbon atoms. The monovalent hydrocarbon group may be linear or branched. Moreover, the monovalent hydrocarbon group may consist of a ring structure or may contain a ring structure. The monovalent hydrocarbon group may be a monovalent saturated hydrocarbon group or a monovalent unsaturated hydrocarbon group.
The monovalent hydrocarbon group is preferably an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, an alkyl group having 2 to 12 carbon atoms, a cycloalkyl group having 6 to 10 carbon atoms, or a cycloalkyl group having 6 to 10 carbon atoms. An alkyl group, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms is more preferable.
Specific examples of the alkyl group include a methyl group, an ethyl group, a tert-butyl group, a hexyl group, a nonyl group, a decyl group, and a dodecyl group.
Specific examples of the cycloalkyl group include a cyclohexyl group.
Specific examples of the cycloalkylalkyl group include a cyclohexylmethyl group.
Specific examples of the aralkyl group include a benzyl group.
Specific examples of the aryl group include a phenyl group and a naphthyl group.

The monomer 2 may use 2 or more types together.
Specific examples of the monomer 2 include ethyl vinyl ether, tert-butyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, vinyl acetate, pivalic acid vinyl ester, neononanoic acid vinyl ester (trade name “Veoba 9” manufactured by HEXION). Neodecanoic acid vinyl ester (manufactured by HEXION, trade name “Beova 10”), benzoic acid vinyl ester, tert-butyl (meth) acrylate, and benzyl (meth) acrylate.
When the modified polymer includes the unit 2, the content of the unit 2 is preferably 1 to 70 mol% and more preferably 10 to 50 mol% with respect to all units included in the modified polymer.

As a method for producing a modified polymer in the present invention, a method in which a specific fluorine-containing polymer is reacted with a polyester having at least one terminal group among a hydroxyl group and a carboxy group (hereinafter also referred to as “Production Method 1”). And a method of adding and reacting the specific fluorine-containing polymer in the production process of the polyester (hereinafter also referred to as “production method 2”), as well as monomer F, monomer 1 and unit P. And a method of reacting the obtained monomer (hereinafter also referred to as “production method 3”). Among these, the manufacturing method 1 is preferable at the point from which the modified polymer containing the homogeneous unit P is easy to be obtained, and the manufacturing method 2 is preferable at the point of production efficiency and reaction rate.
Here, specific examples of the production method 2 include a method of obtaining a modified polymer by reacting a polycarboxylic acid, a polyhydric alcohol and a specific fluorine-containing polymer, and a transesterification reaction between an ester and a specific fluorine-containing polymer. Examples thereof include a method for obtaining a modified polymer, a ring-opening polymerization of lactone, and a method for obtaining a modified polymer by a reaction between a ring-opening polymer of lactone and a specific fluorine-containing polymer. The production method 2 is preferably a method in which a modified polymer is obtained by reacting a polycarboxylic acid, a polyhydric alcohol, and a specific fluorine-containing polymer from the viewpoint of excellent unit P production efficiency. Specific examples of the polycarboxylic acid, polyhydric alcohol, ester and lactone are as described for the unit P.
In any production method, raw materials (specific fluorine-containing polymer and polyester in production method 1, specific fluorine-containing polymer, polyvalent carboxylic acid and polyhydric alcohol in production method 2, each monomer in production method 3) are used. Alternatively, the modified polymer may be produced by dissolving it in water or an organic solvent and reacting it, or the raw material may be mixed in the form of a solid, heated and melted and reacted to produce a modified polymer. From the viewpoint of efficiently generating the units P, the solid-state specific fluoropolymer, polyhydric alcohol and polycarboxylic acid are heated at 200 ° C. to 300 ° C. (preferably 200 ° C. to 250 ° C.). It is preferable to obtain a solid modified polymer by cooling after reacting while melting.
The modified polymer produced by the above method may be pulverized by a known pulverizer to form a powder.

The specific fluoropolymer includes unit F and unit 1, and may further include unit 2. Examples of the method for producing the specific fluoropolymer include a method obtained by copolymerizing each monomer in the presence of a solvent and a radical polymerization initiator.
The content of the unit F is 20 to 70 mol%, preferably 40 to 60 mol%, from the viewpoint of the weather resistance of the present coating film, with respect to all units contained in the specific fluoropolymer.
The content of unit 1 is preferably 1 to 40 mol%, more preferably 1 to 25 mol%, still more preferably 5 to 25 mol%, and more preferably 5 to 20 mol, based on all units contained in the specific fluoropolymer. % Is particularly preferred.
When the specific fluorine-containing polymer includes the unit 2, the content of the unit 2 is preferably 1 to 70 mol%, more preferably 10 to 50 mol%, based on all units included in the specific fluorine-containing polymer.

When the specific fluoropolymer contains the unit 11, the acid value of the specific fluoropolymer is preferably 1 to 250 mgKOH / g.
When the specific fluorine-containing polymer contains units 12, the hydroxyl value of the specific fluorine-containing polymer is preferably 1 to 250 mgKOH / g.
When the acid value and hydroxyl value of the specific fluoropolymer are in the above ranges, the reactivity with the specific fluoropolymer and polyester is excellent.
The Mw of the specific fluoropolymer is preferably from 5,000 to 100,000, more preferably from 8,000 to 80,000.

  The polyester that can be used for the production of the modified polymer according to Production Method 1 may be a polyester having only a hydroxyl group or a carboxy group as a terminal group, or a polyester having a hydroxyl group and a carboxy group as terminal groups. In particular, the latter polyester (that is, a polyester in which one terminal group is a hydroxyl group and the other terminal group is a carboxy group) is preferable.

As the polyester, a polymer containing a polyvalent carboxylic acid residue and a polyhydric alcohol residue is used, and if necessary, a residue other than this (for example, a hydroxycarboxylic acid residue) may be contained. . Specific examples of the polyvalent carboxylic acid and the polyhydric alcohol are as described for the unit P.
As the polyester, commercially available products may be used. Specific examples include “CRYLCOAT (registered trademark) 4642-3”, “CRYLCOAT (registered trademark) 4890-0”, and “CRYLCOAT (registered trademark) 4842” manufactured by Daicel Ornex. -3 "," Iupica Coat (registered trademark) GV-250 "," Iupica Coat (registered trademark) GV-740 "," Iupica Coat (registered trademark) GV-175 "," Iupica Coat (registered trademark) GV- 110 ”,“ Uralac® 1680 ”manufactured by DSM.

The acid value and hydroxyl value of the polyester are each preferably 1 to 250 mgKOH / g from the viewpoint of reactivity with the specific fluoropolymer and coating strength.
The Mn of the polyester is preferably 100 to 100,000, more preferably 100 to 10,000, and particularly preferably 500 to 8,000, from the viewpoint of suitably melting the powder coating material to form a dense coating film.

Examples of the reaction between the specific fluoropolymer and the polyester include a dehydration reaction.
Here, the modified polymer of the first aspect and the second aspect includes a unit P (for example, a unit represented by the formula (P1)).
Specific examples of the method for producing the modified polymer of the first aspect include a specific fluorine-containing polymer, and a polyester having a hydroxyl group or a carboxy group at one end and a hydroxyl group or a carboxy group at the other end. And a method of reacting the unit 1 of the specific fluoropolymer with a terminal group of the polyester, and a method of reacting the unit 1 of the specific fluoropolymer with a polycarboxylic acid and a polyhydric alcohol. Examples of these methods include a method of reacting a hydroxyl group of a specific fluorine-containing polymer with a carboxy group which is one terminal group of a polyester, a hydroxyl group which is a carboxy group of a specific fluorine-containing polymer and one terminal group of a polyester. And a method of reacting with. In this case, what is necessary is just to adjust suitably reaction conditions or the usage-amount of each raw material, etc. so that a part of unit 1 of a specific fluoropolymer may be introduce | transduced into a modified polymer with unreacted.
Examples of the method for producing the modified polymer of the second aspect include the method described in the first aspect. In this case, the reaction conditions or the amount of each raw material used may be adjusted as appropriate so that all the units 1 of the specific fluoropolymer are deactivated.

The modified polymer containing the unit represented by the said Formula (P1-1) or the unit represented by the said Formula (P1-2) can be manufactured as follows, for example.
Specifically, when a specific fluorine-containing polymer containing the unit 11 and a polyester having a hydroxyl group at one end and a group represented by Z in the above formula (P1) at the other end, The hydroxyl group of the polyester and the carboxy group of the unit 11 undergo a dehydration reaction to obtain a modified polymer containing a unit represented by the above formula (P1-1).
Moreover, when using the specific fluorine-containing polymer containing the unit 12 and a polyester having a carboxy group at one end and the group represented by Z in the above formula (P1) at the other end, the unit 12 The hydroxyl group of this and the carboxy group of polyester dehydrate, and the modified polymer containing the unit represented by said Formula (P1-2) is obtained.

The dehydration reaction between the specific fluoropolymer and polyester is preferably carried out in the presence of a condensing agent from the viewpoint of promoting the reaction. Examples of the condensing agent include dehydrating condensing agents and condensing agents other than dehydrating condensing agents.
Specific examples of the dehydrating condensing agent include alkali hydroxide, alkali carbonate, piperidine, diethylamine, alkali metal amide, hydrogen chloride, zinc chloride, potassium hydrogen sulfite silica gel, ion exchange resin, and molecular sieve. Two or more dehydration condensing agents may be used in combination.
Specific examples of the condensing agent other than the dehydrating condensing agent include antimony trioxide, antimony acetate, zinc, and germanium oxide.
The amount of the condensing agent used is 0.001 to 20 based on 100 parts by mass of the total amount of the fluoropolymer and polyester, or the fluoropolymer, polyvalent carboxylic acid and polyhydric alcohol. A mass part is preferable and 0.01-10 mass parts is more preferable.

The reaction temperature between the specific fluoropolymer and the polyester is preferably 30 to 300 ° C, more preferably 100 to 270 ° C, and particularly preferably 170 to 250 ° C, from the viewpoint that the specific fluoropolymer melts and promotes the reaction. preferable. The reaction time is preferably 2 to 20 hours, more preferably 2 to 15 hours.
The ratio of the amount (mass) of the polyester used to the amount (mass) of the specific fluoropolymer used in the production of the modified polymer according to Production Method 1 is the ratio of the mass of the polyester / the mass of the specific fluoropolymer. From the viewpoint of weather resistance and from the viewpoint that a concentration gradient of fluorine content is likely to occur in the present coating film, 0.01 to 20, preferably 0.1 to 9, more preferably 2.0 to 9.0, 2.0 to 5.0 is particularly preferable.
In the production of the modified polymer by production method 2, the ratio of the total amount (mass) of the polyvalent carboxylic acid and polyhydric alcohol to the amount (mass) of the specific fluoropolymer (polyvalent carboxylic acid and polyhydric alcohol) Is preferably from 0.01 to 20 in terms of the weather resistance of the coating film and the concentration gradient of fluorine content in the coating film. To 9 is more preferable, 2.0 to 9.0 is more preferable, and 2.0 to 5.0 is particularly preferable.

The Tg of the modified polymer is preferably 40 to 120 ° C, more preferably 45 to 120 ° C, further preferably 50 to 100 ° C, and particularly preferably 50 to 80 ° C, from the viewpoint of improving the blocking resistance of the powder coating material. 50 to 75 ° C. is most preferable.
The Mw of the modified polymer is preferably 1000 to 100,000, more preferably 5,000 to 80,000, from the viewpoint of suitably melting the powder coating material to form a dense coating film.
The content of the modified polymer is preferably 1 to 100% by mass with respect to the total mass of the powder coating material.

The powder coating material of the present invention can be produced by pulverizing a modified polymer into a powder form, and mixing a powdered resin and additives other than the modified polymer as necessary. Moreover, the powder coating material of the present invention can also be produced in the form of powder by melt-kneading the modified polymer and, if necessary, other resin or additive in powder form and pulverizing.
In addition, the powder coating material of this invention may contain the specific fluoropolymer and polyester which remain | survived unreacted in manufacture of a modified polymer.

The powder coating material of the present invention may contain a fluorinated polymer different from the modified polymer (hereinafter also referred to as “other fluorinated polymer”). Examples of the other fluoropolymer include the specific fluoropolymer used in the production of the modified polymer described above.
In this case, a coating film is obtained in which a layer mainly composed of a modified polymer and a layer mainly composed of another fluoropolymer are arranged in this order on the substrate. At this time, in the layer mainly composed of the modified polymer, the portion mainly composed of the unit F having a high fluorine content is in contact with the layer mainly composed of another fluorine-containing polymer. Interlayer adhesion between the layer and a layer mainly composed of another fluoropolymer is excellent. Moreover, since the part which mainly has the unit P with a low fluorine content adheres to a base material among the layers which mainly have a modified polymer, the base-material adhesiveness of this coating film is excellent.
When the powder coating material of the present invention contains another fluoropolymer, the content of the other fluoropolymer is preferably 1 to 90% by mass, and 1 to 70% by mass with respect to the total mass of the powder coating material. % Is more preferable.
The layer mainly composed of a modified polymer is a layer that contains no polymer other than the modified polymer or contains a smaller mass than the modified polymer. Similarly, the layer mainly composed of a fluoropolymer is a layer that contains no polymer other than the fluoropolymer or, if included, contains less mass than the fluoropolymer, and is mainly composed of polyester. A layer is a layer which contains a polymer other than polyester or contains less polymer than polyester when it contains.

The powder coating material of the present invention may contain a polyester different from the modified polymer (hereinafter also referred to as “other polyester”). Examples of the other polyester include the polyester used in the production of the modified polymer described above.
In this case, a coating film is obtained in which a layer mainly composed of another polyester and a layer mainly composed of a modified polymer are arranged in this order on the substrate. At this time, in the layer mainly composed of the modified polymer, the portion mainly composed of the unit P having a low fluorine content is in contact with the layer mainly composed of the other polyester. Therefore, the layer mainly composed of the modified polymer, Interlayer adhesion with other polyester-based layers is excellent.
When the powder coating material of this invention contains other polyester, 1-90 mass% is preferable with respect to the total mass of a powder coating material, and 1-70 mass% is more preferable.

  The powder coating material of the present invention may contain both other fluoropolymers and other polyesters. In this case, a coating film in which a layer mainly composed of another polyester, a layer mainly composed of a modified polymer, and a layer mainly composed of another fluoropolymer are arranged in this order on the substrate. can get. As described above, the layer mainly composed of the modified polymer is located between the layer mainly composed of another polyester and the layer mainly composed of another fluoropolymer, so that the interlayer adhesion of each layer is excellent. . Furthermore, the substrate adhesion of the present coating film is excellent due to the other polyester-based layer disposed on the substrate side, and the present coating film is composed of the other fluoropolymer disposed on the coating film surface. Excellent weather resistance.

  The powder coating material of the present invention may contain a resin other than those described above. Examples of the resin other than the above include (meth) acrylic resin, epoxy resin, and urethane resin.

  The powder coating material of the present invention may contain components other than those described above (hereinafter referred to as “additives”) as necessary. Specific examples of additives include curing agents, pigments, UV absorbers (various organic UV absorbers, inorganic UV absorbers, etc.), light stabilizers (hindered amine light stabilizers, etc.), matting agents (ultrafine powder synthesis) Silica, etc.), leveling agent, surface conditioner (improves the surface smoothness of the coating film), curing catalyst, degassing agent, plasticizer, filler, thermal stabilizer, dispersant, antistatic agent, rust prevention Agents, silane coupling agents, antifouling agents, and low-contamination treatment agents.

The powder coating material of the present invention preferably contains a curing agent as an additive.
The curing agent is a compound having two or more groups that can react with a hydroxyl group or a carboxy group in one molecule, and crosslinks the modified polymer. The curing agent usually has 2 to 30 groups that can react.
The curing agent when the modified polymer has a hydroxyl group is preferably a compound having two or more isocyanate groups or blocked isocyanate groups in one molecule.
When the modified polymer has a carboxy group, the curing agent is preferably a compound having two or more epoxy groups, carbodiimide groups, oxazoline groups or β-hydroxyalkylamide groups in one molecule.
When the modified polymer has both a hydroxyl group and a carboxy group, a compound having two or more isocyanate groups or blocked isocyanate groups in one molecule and one epoxy group, carbodiimide group, oxazoline group or β-hydroxyalkylamide group It is preferable to use together two or more compounds in the molecule.

The compound having two or more isocyanate groups in one molecule is preferably a polyisocyanate monomer or a polyisocyanate derivative.
The polyisocyanate monomer is preferably an alicyclic polyisocyanate, an aliphatic polyisocyanate, or an aromatic polyisocyanate. The polyisocyanate derivative is preferably a multimer or modified product of a polyisocyanate monomer.

Specific examples of the aliphatic polyisocyanate include aliphatic diisocyanates such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-diisocyanatohexane, and lysine diisocyanate, and Examples include lysine triisocyanate, 4-isocyanatomethyl-1,8-octamethylene diisocyanate, and bis (2-isocyanatoethyl) 2-isocyanatoglutarate.
Specific examples of the alicyclic polyisocyanate include alicyclic diisocyanates such as isophorone diisocyanate, 1,3-bis (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, norbornene diisocyanate, and hydrogenated xylylene diisocyanate. Is mentioned.
Specific examples of the aromatic polyisocyanate include aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, naphthalene diisocyanate, and xylylene diisocyanate.

The compound having two or more blocked isocyanate groups in one molecule is preferably a compound in which two or more isocyanate groups of the above-mentioned polyisocyanate monomer or polyisocyanate derivative are blocked with a blocking agent.
The blocking agent is a compound having active hydrogen, and specific examples include alcohol, phenol, active methylene, amine, imine, acid amide, lactam, oxime, pyrazole, imidazole, imidazoline, pyrimidine, and guanidine.

  Specific examples of compounds having two or more epoxy groups in one molecule include bisphenol type epoxy compounds (A type, F type, S type, etc.), diphenyl ether type epoxy compounds, hydroquinone type epoxy compounds, naphthalene type epoxy compounds, biphenyl type. Epoxy compound, fluorene type epoxy compound, hydrogenated bisphenol A type epoxy compound, bisphenol A nucleated polyol type epoxy compound, polypropylene glycol type epoxy compound, glycidyl ester type epoxy compound, glycidyl amine type epoxy compound, glyoxal type epoxy compound, alicyclic Type epoxy compound, alicyclic polyfunctional epoxy compound, and heterocyclic type epoxy compound (triglycidyl isocyanurate, etc.).

  Specific examples of the compound having two or more carbodiimide groups in one molecule include alicyclic carbodiimide, aliphatic carbodiimide, and aromatic carbodiimide, and multimers and modified products thereof.

  Specific examples of the compound having two or more oxazoline groups in one molecule include an addition polymerizable oxazoline having a 2-oxazoline group and a polymer of the addition polymerizable oxazoline.

  Specific examples of the compound having two or more β-hydroxyalkylamide groups in one molecule include N, N, N ′, N′-tetrakis- (2-hydroxyethyl) -adipamide (PrimidXL-552, manufactured by EMS). N, N, N ′, N′-tetrakis- (2-hydroxypropyl) -adipamide (Primid QM1260PrimidXL-552, manufactured by EMS).

  When the powder coating material of this invention contains a hardening | curing agent, 1-100 mass parts is preferable with respect to 100 mass parts of modified polymers in a powder coating material, and 1-50 mass parts is more. preferable.

The powder paint of the present invention preferably contains a pigment such as a rust preventive pigment, extender pigment, or colored pigment as an additive.
Specific examples of the rust preventive pigment include cyanamide zinc, zinc oxide, zinc phosphate, calcium magnesium phosphate, zinc molybdate, barium borate, and calcium cyanamide zinc.
Specific examples of the extender include talc, barium sulfate, mica, and calcium carbonate.

Specific examples of color pigments include quinacridone, diketopyrrolopyrrole, isoindolinone, indanthrone, perylene, perinone, anthraquinone, dioxazine, benzimidazolone, triphenylmethanequinophthalone, anthrapyrimidine, chrome lead, phthalocyanine, halogenated Examples include phthalocyanines, azo pigments (azomethine metal complexes, condensed azo, etc.), titanium oxide, carbon black, iron oxide, copper phthalocyanine, and condensed polycyclic pigments.
Further, examples of the coloring pigment include a luster pigment, and specific examples include metal particles (metals such as aluminum, zinc, copper, bronze, nickel, titanium, and stainless steel and alloys thereof), mica particles (mica powder), Examples include pearl particles, graphite particles, glass flakes, and scale-like iron oxide particles.
The content when the powder coating material of the present invention contains a pigment is preferably 50% by mass or less based on the total mass of the powder coating material from the viewpoint of the weather resistance of the coating film.

The following method is mentioned as a specific example of the manufacturing method of the powder coating material in this invention.
First, the modified polymer obtained as described above and, if necessary, other components (other resins, pigments, curing agents, curing catalysts, and other additives) at 80 to 130 ° C. Melt-kneaded product is obtained by melt-kneading. Next, the obtained melt-kneaded product is cooled to obtain a solidified melt-kneaded product. Then, if the solidified melt-kneaded product is pulverized and classified, a powder coating material having a desired particle diameter can be obtained.
Alternatively, the modified polymer powder obtained as described above and, if necessary, at least other components (powder of other resin, pigment, curing agent, curing catalyst, and other additives) A powder coating material may be obtained by dry blending at least one kind of powder containing one kind.
As for the average particle diameter of the powder particle which comprises the powder coating material of this invention, 1-100 micrometers is preferable. The average particle size of the powder coating is more preferably 25 μm or more, and more preferably 50 μm or less.
If the average particle diameter is 1 μm or more, the cohesiveness of the powder coating is lowered, and it is easy to apply uniformly during powder coating. Moreover, if an average particle diameter is 100 micrometers or less, the surface smoothness of this coating film will become more favorable, and it will be excellent in the external appearance of this coating film.

The base material with a coating film of this invention has a base material and the coating film (this coating film) formed on a base material with the said powder coating material.
Specific examples of the material of the substrate include inorganic materials, organic materials, and organic-inorganic composite materials.
Specific examples of the inorganic material include concrete, natural stone, glass, metal (iron, stainless steel, aluminum, copper, brass, titanium, etc.).
Specific examples of the organic material include plastic, rubber, adhesive, and wood.
Specific examples of the organic-inorganic composite material include fiber reinforced plastic, resin reinforced concrete, and fiber reinforced concrete.
The base material may be subjected to a known surface treatment (chemical conversion treatment or the like). Further, a resin layer (polyester, acrylic resin, etc.) may be formed on the surface of the substrate.

Among the above, the material of the base material is preferably a metal, and more preferably aluminum. The base material made of aluminum is excellent in corrosion resistance, is lightweight, and is suitable for building material applications such as exterior members.
The shape, size, etc. of the substrate are not particularly limited.
Specific examples of base materials include composite panels, curtain wall panels, curtain wall frames, architectural exterior members such as window frames, tire wheels, wiper blades, automotive exterior automotive elements such as automobile exteriors, construction equipment, and motorcycles. Frame.

  The film thickness of this coating film is preferably 20 to 1000 μm, and more preferably 20 to 500 μm. In applications such as members for high-rise buildings such as aluminum curtain walls, 20 to 90 μm is preferable. For applications with high weather resistance requirements such as outdoor units of air conditioners installed along the coast, signal poles, signs, etc., 100 to 200 μm is preferable.

  The method for producing a substrate with a coating film of the present invention comprises forming the coating layer by applying the powder coating material of the present invention onto the substrate, and heating the coating layer to form the coating film on the substrate. It is preferable to manufacture. In addition, a base material with a coating film can be paraphrased as a coated article.

As a method for forming the coating layer, the powder coating material of the present invention is used as a base material by a coating method such as electrostatic coating method, electrostatic spraying method, electrostatic dipping method, spraying method, fluidized dipping method, spraying method, spraying method, etc. The method of painting on top is preferred. The electrostatic coating method using a powder coating gun is preferable because it is excellent in surface smoothness and concealing property of the coating film.
Specific examples of the powder coating gun include a corona charging type coating gun and a friction charging type coating gun. The corona charging type coating gun is a coating gun that sprays powder coating after corona discharge treatment. The frictional charging type coating gun is a coating gun that sprays powder coating by friction charging.

When the coating layer is heat-treated, it is preferable to heat the coating layer on the substrate to form a molten film made of a powder paint melt on the substrate. In addition, formation of a molten film may be performed simultaneously with formation of the coating layer to a base material, and may be performed separately after forming a coating layer.
The heating temperature and heating maintenance time for heating and melting the powder coating and maintaining the melted state for a predetermined time are appropriately set according to the type and composition of the raw material components of the powder coating, the desired coating thickness, etc. Is done.

For example, when the modified polymer in the powder coating material of the present invention has a carboxy group, the carboxy group has a curing agent (an epoxy group, a carbodiimide group, an oxazoline group, or a β-hydroxyalkylamide group having two or more in one molecule). ) And the coating layer hardens at a lower temperature. The reaction between a carboxy group and a curing agent has an advantage that a high temperature (about 200 ° C.) is not required as in the case of using a curing agent having an isocyanate group.
The heating temperature is preferably 120 ° C to 200 ° C. The heating maintenance time is usually 2 to 60 minutes.
It is preferable to form this coating film by cooling the molten film formed on the substrate to 20 to 25 ° C. The cooling may be rapid cooling or slow cooling, and slow cooling is preferred from the viewpoint of adhesion of the coating film to the substrate.

  Hereinafter, the present invention will be described in detail with examples. However, the present invention is not limited to these examples. In addition, the compounding quantity of each component in the table | surface mentioned later shows a mass reference | standard. Examples 8-12 are examples and examples 13 and 14 are comparative examples.

<Used ingredients>
(Specific fluorine-containing polymer)
Fluoroolefin: Chlorotrifluoroethylene (CTFE)
Monomer 1: 4-hydroxybutyl vinyl ether (HBVE), 10-undecylenic acid (UDA)
Monomer 2: Neononanoic acid vinyl ester (V9) (manufactured by HEXION, trade name “Veoba 9”), cyclohexyl vinyl ether (CHVE), ethyl vinyl ether (EVE)
(polyester)
Polyester 1: Mn is 2,500, softening point is 120 ° C., units based on ethylene glycol, units based on neopentyl glycol, units based on terephthalic acid, units based on isophthalic acid in this order 5 mol%, 45 mol %, 18 mol%, and 32 mol% polyester, wherein one polymer terminal group is a carboxy group and the other polymer terminal group is a hydroxyl group

(Additive)
Dehydration condensing agent 1: dodecylbenzenesulfonic acid Curing agent 1: Compound having two or more blocked isocyanate groups in one molecule (Evonik, Vestagon (registered trademark) B1530)
Curing agent 2: Compound having 2 or more epoxy groups in one molecule (manufactured by HUNTSMAN, PT-910 (trade name))
Surface conditioner: BYK-360P (trade name) manufactured by Big Chemie
Degassing agent: Benzoin Pigment: Titanium oxide pigment (DuPont, Ti-Pure R960 (trade name), titanium oxide content: 89% by mass)
Curing catalyst: Dibutyltin dilaurate xylene solution (100-fold diluted product)

<Production of specific fluorine-containing polymer>
[Example 1]
In an autoclave, 50% by weight of xylene (503 g), ethanol (142 g), CTFE (387 g), CHVE (326 g), HBVE (84.9 g), potassium carbonate (12.3 g), and tert-butyl peroxypivalate. A xylene solution (20 mL) was introduced, the temperature was raised, and polymerization was carried out at 65 ° C. for 11 hours. Then, the solution in an autoclave was filtered and the solution containing the specific fluoropolymer 1 was obtained.
The solution containing the specific fluoropolymer 1 is vacuum-dried at 65 ° C. for 24 hours to remove the solvent, and further vacuum-dried at 130 ° C. for 20 minutes to pulverize the block-shaped specific fluoropolymer. Thus, a powdery specific fluoropolymer 1 was obtained.
The specific fluoropolymer 1 was a polymer containing 50 mol%, 39 mol%, and 11 mol% of a unit based on CTFE, a unit based on CHVE, and a unit based on HBVE in this order. The hydroxyl value of the specific fluoropolymer 1 was 50 mgKOH / g, Tg was 52 ° C., and Mw was 45,500.

[Example 2]
Example 1 with the exception that the monomer used is changed to CTFE (465 g), V9 (631 g), and UDA (103 g) and the solvent is changed to tert-butyl alcohol (422 g) and ethanol (106 g). Similarly, powdery specific fluoropolymer 2 was obtained.
The specific fluoropolymer 2 was a polymer containing 50 mol%, 43 mol%, and 7 mol% of a unit based on CTFE, a unit based on V9, and a unit based on UDA in this order. The acid value of the specific fluoropolymer 2 was 33 mgKOH / g, the Tg was 50 ° C., and the Mw was 49,000.

[Example 3]
A powdery specific fluoropolymer 3 is obtained in the same manner as in Example 1 except that the monomer used is changed to CTFE (465 g), CHVE (151 g), EVE (138 g) and HBVE (102 g). It was.
The specific fluoropolymer 3 is a polymer containing 50 mol%, 15 mol%, 24 mol%, and 11 mol% in this order of units based on CTFE, units based on CHVE, units based on EVE, and units based on HBVE. It was. The hydroxyl value of the specific fluoropolymer 3 was 57 mgKOH / g, the Tg was 40 ° C., and the Mw was 45,000.

<Production of modified polymer>
[Example 4]
A powdery specific fluoropolymer 1 (120 g) and a dehydrating condensing agent 1 (5 g) are placed in a reactor, the internal temperature is maintained at 130 ° C. while stirring the reactor, and polyester 1 (280 g) is further added. And reacted for 4 hours. The solid obtained by gradually cooling the reactor was recovered, pulverized, washed with water, and dried to obtain a powder. The obtained powder had an Mw of 49,000, an acid value of 20 mgKOH / g, a hydroxyl value of 30 mgKOH / g, a Tg of 57 ° C., and the specific fluoropolymer 1 and polyester were It was confirmed that this was a modified polymer 1 having a unit represented by the following formula (P1-2a) formed by dehydration reaction.

In formula (P1-2a), A ^2a is — (A ¹² —C (O) O—A ¹¹ —OC (O)) _n2 —A ¹² —C (O) O—A ¹¹ —, and Z ^2a is -OH.
In the formula, A ¹¹ is a residue obtained by removing a hydroxyl group from ethylene glycol or neopentyl glycol, A ¹² is a residue obtained by removing a carboxy group from terephthalic acid or isophthalic acid, and n2 is an average value 2 It is an integer above.

[Example 5]
Into the autoclave, terephthalic acid (209 g), isophthalic acid (371 g), ethylene glycol (279 g), and neopentyl glycol (52 g) were introduced, and the temperature was gradually raised from 100 ° C., followed by reaction at 250 ° C. for 4 hours. After that, 0.15 g of antimony trioxide was added and reacted at 280 ° C. for 3 hours. Thereafter, the temperature was lowered to 230 ° C., the specific fluorine-containing polymer 1 (360 g) was added, and the mixture was further reacted for 4 hours. The solid obtained by gradually cooling the reactor was collected, pulverized, washed with water, and dried to obtain a powdery modified polymer 2 containing a unit represented by the above formula (P1-2a). Modified polymer 2 had an Mw of 49,500, an acid value of 22 mgKOH / g, a hydroxyl value of 28 mgKOH / g, and a Tg of 59 ° C.

[Examples 6 to 7]
The specific fluoropolymer 2 and polyester were formed by dehydration reaction in the same manner as in Example 4 except that the specific fluoropolymer 2 or the specific fluoropolymer 3 was used instead of the specific fluoropolymer 1. The powdered modified polymer 3 having a unit represented by the following formula (P1-1a), the specific fluorine-containing polymer 3 and the polyester are represented by the above formula (P1-2a) formed by dehydration condensation. Each of the powdery modified polymers 4 having the following units was obtained. Modified polymer 3 and modified polymer 4 have Mw of 53,000 and 54,000 in this order, acid values of 20 mgKOH / g and 23 mgKOH / g in this order, and hydroxyl values of 13 mgKOH / g in this order, The Tg was 53 ° C. and 48 ° C. in this order.

In formula (P1-1a), A ^1a is — (A ¹¹ —OC (O) —A ¹² —C (O) O) _n1 —A ¹¹ —OC (O) —A ¹² —, and Z ^1a is — C (O) OH.
In the formula, A ¹¹ is a residue obtained by removing a hydroxyl group from ethylene glycol or neopentyl glycol, A ¹² is a residue obtained by removing a carboxy group from terephthalic acid or isophthalic acid, and n1 is an average value 2 It is an integer above.

<Manufacture and evaluation of powder coating materials and coated substrates>
[Examples 8 to 14]
Each component described in Table 1 was mixed with a high-speed mixer, and melt-kneaded at a barrel set temperature of 120 ° C. using a twin-screw extruder to obtain pellets. The pellets were pulverized at 25 ° C. using a pulverizer and further classified using a 150-mesh net to obtain powder coating materials 1 to 7 composed of particles having an average particle diameter of 40 μm.

[Evaluation example of powder coating]
Each powder coating is electrostatically coated on one side of the chromate-treated aluminum plate (base material) using an electrostatic coating machine (GX3600C, manufactured by Onoda Cement Co., Ltd.) and held in a 200 ° C. atmosphere for 20 minutes. And the aluminum plates 1-7 with a coating film formed from each powder coating material 1-7 were obtained. The aluminum plate with a coating film was used for the below-mentioned evaluation as test pieces 1-7.

[Blocking resistance of powder coatings]
Each powder coating was put in a bottle and sealed, the sealed bottle was stored at 30 ° C., and the time until the powder coating blocked was observed.
S: No blocking when 15 days have passed.
A: Blocking occurs after 2-14 days.
B: Blocking within one day.

[Interlayer adhesion of coating film]
The determination was made by the pull-off method (JIS K5600-5-7). The coating film was peeled from the test plate, and the following criteria were evaluated from the state of the substrate surface after peeling. In addition, in this evaluation test, it can be said that the state in which the coating film is peeled off from the substrate and the coating film does not remain on the surface of the substrate is most excellent in the interlayer adhesion of the coating film.
S: A part of the coating film having a thickness less than the film thickness of the coating film before the peeling test remains in less than 5% of the surface area of the substrate.
A: A part of the coating film having a thickness less than 5% to less than 15% of the surface area of the substrate is less than the film thickness of the coating film before the peeling test.
B: A part of the coating film having a thickness less than the film thickness of the coating film before the peeling test is observed at 15% or more of the surface area of the substrate.

[Weather resistance of coating film]
Using a xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.), the time until the coating film peeled when 1% by mass of hydrogen peroxide was sprayed on the coating film was measured.
<Test conditions>
Relative humidity: 70% RH
Temperature: 50 ° C
Light source: 80 W / m ² (wavelength: 300 to 400 nm).
<Criteria>
SS: Peeling occurred for the first time in over 300 hours.
S: Peeling occurred for the first time in more than 270 hours and not more than 300 hours.
A: Exfoliation occurred for the first time in over 100 hours and 270 hours or less.
B: Peeling occurred for the first time in 100 hours or less.
The evaluation results are shown in Table 1.

In the weather resistance evaluation of the test pieces of Example 13 and Example 14, peeling of the surface layer portion of the coating film considered to be a layer mainly composed of the specific fluoropolymer was observed.
As described above, if a powder coating containing a fluorine-containing modified polymer having a predetermined hydroxyl value or a predetermined acid value, which contains a unit based on fluoroolefin and a unit having a polyester chain in the side chain, is used for interlayer adhesion (Example 8 to Example 12).

Claims (17)

  A fluorine-containing modified polymer comprising a unit having a polyester chain in the side chain and a unit based on a fluoroolefin, the hydroxyl group or acid value being 1 to 200 mgKOH / g Powder coating.   The polyester chain unit has a side chain functional group of a unit having at least one side chain functional group among a hydroxyl group and a carboxy group, and a polyester having at least one terminal group among a hydroxyl group and a carboxy group. The powder coating material according to claim 1, wherein the terminal group is a unit having an ester-bonded structure.   The unit having the polyester chain in the side chain is a dehydration polycondensation of the side chain functional group of a unit having at least one side chain functional group among a hydroxyl group and a carboxy group, a polyvalent carboxylic acid, and a polyhydric alcohol. The powder coating material according to claim 1, which is a unit of a structured. The powder coating material of any one of Claims 1-3 whose unit which has a polyester chain in the said side chain is a unit represented by the following Formula (P1).
The symbols in the formula have the following meanings.
R ¹ and R ² are each independently a hydrogen atom or a methyl group.
L is a group derived from a side chain in a unit based on the monomer having the side chain functional group.
A is a polyester chain.
Z is a hydroxyl group or a carboxy group.   The hydroxyl value of the fluorine-containing modified polymer is 10 to 150 mgKOH / g, or the acid value of the fluorine-containing modified polymer is 5 to 150 mgKOH / g. The powder coating described.   The said fluorine-containing modified polymer has a hydroxyl group and a carboxy group, its hydroxyl value is 10-150 mgKOH / g, and its acid value is 5-150 mgKOH / g. Powder coating as described in   The powder coating material of any one of Claims 1-6 whose glass transition temperature of the said fluorine-containing modified polymer is 45-120 degreeC.   The powder according to any one of claims 1 to 7, wherein the content of the unit having the polyester chain in the side chain is 1 to 40 mol% with respect to all units of the fluorine-containing modified polymer. paint.   The powder coating material of any one of Claims 1-8 whose ratio of the mass of the said polyester chain with respect to the mass of the said fluorine-containing modified polymer except the said polyester chain is 2.0-9.0.   The powder coating material of any one of Claims 1-9 containing a hardening | curing agent. It is a manufacturing method of the powder paint according to any one of claims 1 to 10,
A fluorine-containing polymer comprising a unit having at least one side-chain functional group among a hydroxyl group and a carboxy group and a unit based on a fluoroolefin;
A polyester having at least one terminal group among a hydroxyl group and a carboxy group is reacted to obtain a solid fluorine-containing modified polymer,
Next, the method for producing a powder coating material is characterized by pulverizing the fluorine-containing modified polymer.   The manufacturing method of Claim 11 whose ratio of the mass of the said polyester with respect to the mass of the said fluoropolymer is 2.0-9.0.   The production method according to claim 11 or 12, wherein the reaction is carried out in the presence of a condensing agent. It is a manufacturing method of the powder paint according to any one of claims 1 to 10,
A fluorine-containing polymer comprising a unit having at least one side chain functional group among a hydroxyl group and a carboxy group and a unit based on a fluoroolefin, a polyvalent carboxylic acid and a polyhydric alcohol,
A method for producing a powder coating material comprising obtaining a solid fluorine-containing modified polymer and then pulverizing the fluorine-containing modified polymer.   The manufacturing method of Claim 14 whose ratio of the total mass of the said polyhydric carboxylic acid and the said polyhydric alcohol with respect to the mass of the said fluoropolymer is 2.0-9.0.   Applying the powder coating material according to any one of claims 1 to 10 on a substrate to form a coating layer, heat-treating the coating layer to form a coating film on the substrate. The manufacturing method of the base material with a coating film characterized.   It has a base material and the coating film formed on the said base material with the powder coating material of any one of Claims 1-10, The base material with a coating film characterized by the above-mentioned.