JP2007291261A - Fluorine-containing copolymer composition and coating composition using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorine-containing copolymer composition which enables to materialize a coating material difficult to generate bubble trails even after baking at a high temperature for a short time and which is excellent in storage stability and dilution property, and a coating composition using the same. <P>SOLUTION: The fluorine-containing copolymer composition comprises: a fluorine-containing copolymer (A) obtained by polymerizing at least one monomer (a1) selected from fluoroolefins, and at least one monomer (a2) selected from the group consisting of a vinyl ester, a propenyl ether and a propenyl ester; a mixture (B) of aromatic hydrocarbon compounds composed of 9-11C aromatic hydrocarbon compounds as principal constituents; and an organic solvent (C) except for the mixture (B) of aromatic hydrocarbon compounds wherein the naphthalene amount contained in the mixture (B) of aromatic hydrocarbon compounds is not greater than 1 mass%. The coating composition using the same is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fluorine-containing copolymer composition and a coating composition using the same.

The coating composition using a fluorine-containing copolymer as a coating film component can remarkably reduce the number of times of repainting in the life of the casing from the length of the coating film life, and VOC (volatile organic matter) generated in the product life. There is an increasing demand for environmentally friendly paints with a small amount of compound).
In particular, in PCM (pre-coating method), in which metal coils are continuously coated and then processed into final products, it is easy to install equipment such as an afterburner that can process VOC generated during paint baking without releasing it to the outside. There is an increasing demand for copolymer coating compositions.

In PCM coating, from the viewpoint of productivity, coating baking is performed at a high temperature and short time of 230 ° C. or more for several tens of seconds. However, in a coating that is a thermosetting solvent-based coating and uses a single solvent, the coating baking is performed. Since the solvent is rapidly heated to a temperature higher than the boiling point of the solvent, the solvent suddenly boils, and defects such as bubble marks are likely to occur in the coating film.
Therefore, a mixture of aromatic hydrocarbons having a high boiling point of 190 to 220 ° C. has been suitably used as a solvent because the evaporation rate can be easily controlled by reducing the boiling point. Moreover, since the aromatic hydrocarbon mixture alone is inferior in solubility of the resin and it is difficult to maintain a solid content concentration of 40% by mass or more, a high boiling ketone solvent such as cyclohexanone is also used at the same time (for example, Patent Documents 1 and 2).
JP 2004-82120 A JP 2004-115792 A

In the coating composition, a part of the resin may react during storage to increase the viscosity. In that case, since there is a possibility that the coating workability may deteriorate or the coating film performance may deteriorate, good storage stability is required.
In addition, when the coating composition is prepared or painted, if necessary, the fluorine-containing copolymer that was originally dissolved cannot be dissolved if the dilution exceeds a certain level according to the solvent power. The phenomenon of cloudiness occurs. For this reason, even when the degree of dilution is high, white turbidity hardly occurs and good dilutability is required.
However, conventional fluorine-containing copolymer compositions using a high-boiling aromatic hydrocarbon mixture have not been sufficient in terms of storage stability and dilutability.

  The present invention has been made in view of the above circumstances, and can realize a paint that hardly causes bubble marks in a coating film even after baking at a high temperature for a short time, and also has excellent storage stability and dilutability. An object is to provide a composition and a coating composition using the composition.

  A high-boiling aromatic hydrocarbon mixture is produced from crude oil through a distillation process, but naphthalene is mixed during the production. As a result of intensive studies focusing on this mixed naphthalene, the present inventors have reduced the content of naphthalene in the aromatic hydrocarbon mixture, thereby reducing the fluorine-containing copolymer composition and the coating composition using the same. It has been found that the storage stability and dilutability of the product can be improved, and the present invention has been completed.

In order to solve the above problems, the fluorine-containing copolymer composition of the present invention comprises (A) one or more monomers selected from (a1) fluoroolefin and (a2) vinyl ether, vinyl ester, propenyl ether, and A fluorine-containing copolymer obtained by polymerizing one or more monomers selected from the group consisting of propenyl esters; and (B) an aromatic hydrocarbon mixture mainly composed of an aromatic hydrocarbon compound having 9 to 11 carbon atoms. And (C) a fluorine-containing copolymer composition comprising an organic solvent other than (B) the aromatic hydrocarbon mixture, wherein the amount of naphthalene contained in the (B) aromatic hydrocarbon mixture is 1% by mass It is characterized by the following.
Moreover, this invention provides the coating composition containing the fluorine-containing copolymer composition of this invention.

The fluorine-containing copolymer composition of the present invention is excellent in storage stability and dilutability, and when used in a coating material, a coating material in which bubble marks are hardly generated in the coating film even when baking at a high temperature for a short time is obtained. .
The coating composition of the present invention is excellent in storage stability and dilutability, and bubbles are hardly generated in the coating film even if baking is performed at a high temperature for a short time.

<Fluorine-containing copolymer composition>
The fluorine-containing copolymer composition of the present invention is selected from the group consisting of (A) one or more monomers selected from (a1) fluoroolefins and (a2) vinyl ethers, vinyl esters, propenyl ethers and propenyl esters. A fluorine-containing copolymer obtained by polymerizing monomers of at least species, (B) an aromatic hydrocarbon mixture mainly composed of an aromatic hydrocarbon compound having 9 to 11 carbon atoms, and (C) the above (B) It consists of organic solvents other than aromatic hydrocarbon mixtures.

[(A) Fluorine-containing copolymer]
The (A) fluorine-containing copolymer in the present invention is selected from the group consisting of (a1) one or more monomers selected from fluoroolefins and (a2) vinyl ethers, vinyl esters, propenyl ethers, and propenyl esters. It is a copolymer obtained by polymerizing monomers of at least species.

Preferred examples of the monomer (a1) fluoroolefin include chlorotrifluoroethylene (CTFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP) and the like. The fluoroolefin used as the monomer (a1) may be one type or two or more types.
The amount of the monomer (a1) used is preferably 40 to 60 mol%, more preferably 45 to 55 mol%, based on the whole monomer constituting the fluorine-containing copolymer (A). When the amount of the monomer (a1) used is not less than the lower limit of the above range, the fluorine content in the copolymer is sufficient and the weather resistance is excellent, and when it is not more than the upper limit of the above range, solubility in an organic solvent is sufficient. Excellent.

The monomer (a2) is selected from the group consisting of vinyl ether, vinyl ester, propenyl ether, and propenyl ester.
Vinyl ether is a compound represented by the general formula: CH ₂ ═CH (OR ¹ ) (1). R ¹ is, for example, an alkyl group, and specific examples thereof include linear alkyl groups such as methyl, ethyl, butyl and dodecyl; branched alkyl chains such as tert-butyl, iso-butyl and 2-ethylhexyl; cyclohexyl And cyclic alkyl groups such as
The vinyl ester is preferably a carboxylic acid vinyl ester, and examples of the carboxylic acid include benzoic acid, pivalic acid, and itaconic acid.
Propenyl ether is a compound represented by the general formula: CH ₂ = CHCH ₂ (OR ² ) (2) or CH ₂ = C (OR ³ ) CH ₃ (3). Said R < ² >, R < ³ > is an alkyl group, for example, and the specific example similar to the alkyl group as said R < ¹ > is mentioned.
The propenyl ester is preferably a carboxylic acid propenyl ester, and preferred examples of the carboxylic acid include benzoic acid, pivalic acid, and itaconic acid.

Moreover, you may use the monomer (a2 ') which has a functional group which can be bridge | crosslinked as needed as a part of monomer (a2). The monomer (a2 ′) includes a vinyl ether having a crosslinkable functional group, a vinyl ester having a crosslinkable functional group, a propenyl ether having a crosslinkable functional group, and a crosslinkable functional group. It is selected from the group consisting of propenyl esters.
As the monomer (a2 ′), a vinyl ether having a hydroxyl group is preferable, and for example, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, cyclohexyldimethanol vinyl ether and the like are preferable.
The fluorine-containing copolymer composition prepared using the monomer (a2 ′) having a functional group capable of cross-linking reaction is used in the coating film forming step by constituting a coating composition in combination with a curing agent. A functional group and a curing agent react to form a cross-linked bond, and a coating film having excellent physical properties is obtained.

The monomer (a2) may be used alone or in combination of two or more.
The amount of the monomer (a2) used is preferably 40 to 60 mol%, more preferably 45 to 55 mol%, of the whole monomer constituting the fluorinated copolymer (A). When the amount of the monomer (a2) used is within the above range, the solubility in an organic solvent is excellent, and the weather resistance of the coating film is excellent.
When the monomer (a2 ′) having a functional group capable of crosslinking reaction is used as a part of the monomer (a2), the amount of the monomer (a2 ′) used is 5-20 mol% of the total usage-amount of (a2) is preferable, and 6-15 mol% is more preferable. When the amount of the monomer (a2 ′) used is not less than the lower limit of the above range, sufficient functional groups are introduced into the copolymer, the crosslinked state of the formed coating film becomes good, and the coating film performance is excellent. . Further, when the amount is not more than the upper limit of the above range, the polarity of the copolymer becomes appropriate, the solubility in the aromatic hydrocarbon mixture is excellent, the amount of a co-solvent such as cyclohexanone becomes appropriate, and a crack or the like occurs in PCM coating. Hateful.

  The fluorine-containing copolymer (A) comprises a polymerization initiator or ionizing radiation in a mixture containing the monomer (a1) and the monomer (a2) in a predetermined ratio in the presence or absence of a polymerization medium. It can manufacture by making a polymerization initiation source, such as act, and performing a copolymerization reaction.

  The weight average molecular weight (Mw) of the fluorine-containing copolymer (A) measured by gel permeation chromatography (GPC) using polystyrene as a standard substance is preferably 45,000-75,000, 45,000-70, 000 is more preferable. When the mass average molecular weight is not less than the lower limit of the above range, it is excellent in processing performance of a coated article as a PCM application, and when it is not more than the upper limit of the above range, it has excellent solubility in an aromatic hydrocarbon mixture, such as cyclohexanone. The amount of the co-solvent is not increased, and the occurrence of cracks or the like is difficult in PCM coating.

[(B) Aromatic hydrocarbon mixture]
The (B) aromatic hydrocarbon mixture in the present invention is mainly composed of an aromatic hydrocarbon compound having 9 to 11 carbon atoms, and the naphthalene content is 1% by mass or less. A lower naphthalene content is more preferable.
In the present invention, the mixture containing “aromatic hydrocarbon compound having 9 to 11 carbon atoms as the main component” means that the ratio of “aromatic hydrocarbon compound having 9 to 11 carbon atoms” in the mixture is 99 mass. It means exceeding%.
Such (B) aromatic hydrocarbon mixtures can be obtained from commercial products. Specific examples include Cactus Solvent P-140 (product name) manufactured by Japan Energy, Solvesso 150ND (product name) manufactured by ExxonMobil, Hydrosol A200ND (product name) manufactured by DHC, and the like.

  In addition, Solvesso 150 (product name) manufactured by ExxonMobil Co., Ltd. is a commercially available aromatic hydrocarbon mixture mainly composed of an aromatic hydrocarbon compound having 9 to 11 carbon atoms and having a naphthalene content exceeding 1% by mass. ), Cactus Solvent P-150 (product name) manufactured by Japan Energy, and the like.

[(C) Organic solvent]
The fluorine-containing copolymer composition of the present invention contains (C) an organic solvent other than the (B) aromatic hydrocarbon mixture. The organic solvent (C) is not particularly limited as long as the fluorine-containing copolymer can be dissolved. Specific examples include aromatic hydrocarbons having 8 or less carbon atoms such as toluene and xylene; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diisobutyl ketone and isophorone; esters such as ethyl acetate and butyl acetate; n- Examples include alcohols such as butanol and isobutanol.
In particular, those having a boiling point of 150-220 ° C., which is close to the boiling range of the aromatic hydrocarbon mixture used at the same time, are preferred because they are unlikely to cause foaming marks due to bumping by PCM baking, and ketones such as cyclohexanone, diisobutyl ketone and isophorone Are preferred.
(C) One organic solvent may be used, or two or more organic solvents may be used.

  The total content of (B) aromatic hydrocarbon mixture and (C) organic solvent in the fluorinated copolymer composition of the present invention is not particularly limited, and the solid content concentration of the fluorinated copolymer composition is desired. It is set to be in the range.

  The ratio of the content of (B) aromatic hydrocarbon mixture and (C) organic solvent in the fluorine-containing copolymer composition of the present invention is 70 to 90 mass of (B) aromatic hydrocarbon mixture among the total of both. %, And more preferably 75 to 85% by mass. (B) If the content of the aromatic hydrocarbon mixture is not less than the lower limit of the above range, the ratio of the ketone solvent having a single boiling point becomes appropriate, and (B) the effect of relaxing the boiling point by the aromatic hydrocarbon mixture is sufficient. Since the bumping is suppressed, the foamability during rapid heating is not lowered. Moreover, it is excellent in the solubility of a fluorine-containing copolymer as it is below the upper limit of the said range.

<Coating composition>
The coating composition of the present invention contains the fluorine-containing copolymer composition of the present invention. Specifically, a coating composition is obtained by adding a coating additive or the like as required to the fluorine-containing copolymer composition of the present invention. The coating composition can be prepared by a known method.

As the paint additive, generally known additives are appropriately used. Specific examples include various additives such as curing agents, pigments, surface conditioning agents, defoaming agents, rheology control agents, and curing catalysts such as metal soaps, acids, and amines.
When the fluorine-containing copolymer composition to be used contains a fluorine-containing copolymer synthesized using a monomer (a2 ′) having a functional group capable of crosslinking reaction, A reacting curing agent is added, and a curing catalyst is added if necessary.
These may use 1 type as needed, and may use 2 or more types.

When preparing a coating composition using a fluorine-containing copolymer composition, if necessary, a solvent contained in the fluorine-containing copolymer composition may be added and diluted. Moreover, after preparing a coating composition, when using this for coating, you may add and dilute the solvent contained in this coating composition.
As the solvent used for the dilution, it is preferable to use an aromatic hydrocarbon mixture (B) in order to obtain satisfactory properties that hardly cause bubble marks in the coating film even when baking at a high temperature for a short time.

Since the fluorine-containing copolymer composition of the present invention is a mixture of (B) aromatic hydrocarbon mixture contained therein having a high boiling point of about 190 to 220 ° C. and having 10 or more different boiling points, the boiling point When the fluorine-containing copolymer composition is used for a thermosetting coating, a bubble phenomenon hardly occurs in the coating film even if baking is performed at a high temperature for a short time.
Moreover, since the naphthalene content in the (B) aromatic hydrocarbon mixture is reduced in the fluorine-containing copolymer composition of the present invention, the reaction during storage is suppressed, and the storage stability is improved. Thus, the increase in molecular weight during storage is mitigated. Since naphthalene has many substituents and easily changes to a substance that causes an increase in molecular weight, it is considered that the storage stability is improved by reducing this.
In addition, since the fluorine-containing copolymer composition of the present invention has a reduced naphthalene content in the (B) aromatic hydrocarbon mixture, the solubility of the fluorine-containing copolymer in the (B) aromatic hydrocarbon mixture The aromatic hydrocarbon mixture can be added and diluted, and the cloudiness due to dilution can be suppressed. Therefore, good dilutability can be obtained without impairing the property that bubbles are hardly formed in the coating film even when baking at a high temperature for a short time. Since naphthalene is poor in the solubility of the fluorine-containing copolymer, it is considered that the dilutability is improved by reducing this.
Furthermore, since the fluorine-containing copolymer composition contains (C) an organic solvent in addition to (B) the aromatic hydrocarbon mixture as a solvent, good solubility of the fluorine-containing copolymer can be obtained.

  The coating composition of the present invention containing such a fluorine-containing copolymer composition of the present invention is excellent in storage stability and dilution, and has a bubble mark on the coating film even after baking at a high temperature for a short time. The fluorine-containing copolymer has good solubility. Therefore, it is particularly suitable for PCM coating.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
In the following, “%” represents “% by mass” unless otherwise specified.

[Production Example 1: Production of fluorinated copolymer (1)]
In an autoclave with a stainless steel stirrer with an internal volume of 2500 mL, a mixture of 317 g (about 40 mol%) of ethyl vinyl ether (EVE) and 128 g (about 10 mol%) of hydroxybutyl vinyl ether (HBVE), 642 g of xylene, ethanol Introduce 180 g, 10 g of potassium carbonate, 7 g of 50% xylene solution of tert-butyl peroxypivalate (PBPV), and 665 g (about 50 mol%) of chlorotrifluoroethylene (CTFE), and gradually increase the temperature. did. After reaching 65 ° C., it was kept for 20 hours, then cooled, and the residue was removed by filtration.
Ethanol and residual monomers were removed from the xylene solution of the fluorine-containing copolymer thus obtained to obtain a xylene solution of the fluorine-containing copolymer (1).
The resulting fluorine-containing copolymer (1) had a mass average molecular weight (Mw) of 50,000 as determined by gel permeation chromatography (GPC).

[Example 1: Production of coating composition (1)]
500 g of the xylene solution of the fluorinated copolymer (1) obtained in the above production example was put into a 1 L eggplant flask, and an aromatic hydrocarbon mixture (manufactured by Japan Energy, product name: Cactus solvent P140 (naphthalene content) 1% or less))) was introduced.
Next, the pressure was reduced at 60 ° C. to remove xylene, and 75 g of cyclohexanone was added to obtain a fluorine-containing copolymer composition.
This was transferred to a glass container with a stirrer, and 2.2 g of succinic anhydride was added, and then heated to 90 ° C., 0.19 g of triethylamine (TEA) was added, stirred for 3 hours, and nonvolatile. A coating composition (1) having a weight average molecular weight (Mw) of 51,580 by GPC of 40% was obtained.

[Comparative Example 1: Production of coating composition (2)]
In Example 1, except that the aromatic hydrocarbon mixture was changed to “ExxonMobil Corporation, product name: Solvesso 150 (Naphthalene content> 1%)”, the same operation as in Example 1 was performed, and the nonvolatile content 40 %, A coating composition (2) having a mass average molecular weight (Mw) of 51,280 by GPC was obtained.

[Evaluation of coating composition]
The following tests were performed on the coating compositions (1) and (2) obtained in Example 1 and Comparative Example 1, respectively. The results are shown in Table 1.
(Dilution test)
The obtained coating composition was diluted with the aromatic hydrocarbon mixture used for each, and the dilution rate at which white turbidity occurred was measured.
The dilution rate is 200% when diluted with the same amount of aromatic hydrocarbon mixture, with the coating composition (stock solution) having a nonvolatile content of 40% as 100%.
(Storage stability test)
The obtained coating composition was stored in a thermostat at 50 ° C., and the change in mass average molecular weight (Mw) was measured after 4 weeks.

[Example 2: Production of coating composition (3)]
To 8.6 g of the coating composition (1) obtained in Example 1 above, 9.3 g of a hexamethylene diisocyanate-based methyl ethyl ketone oxime block curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Sumidur BL3175), And 3 parts of the acetone 10,000 times dilution solution of dibutyltin dilaurate (DBTDL) were mixed, and the coating composition (3) was obtained.

[Comparative Example 2: Production of coating composition (4)]
In Example 2, the same operation as in Example 2 was performed, except that 84.6 g of the coating composition (1) was changed to 84.6 g of the coating composition (2) obtained in Comparative Example 1 above. A coating composition (4) was obtained.

[Evaluation and results of coating composition]
The following solvent volatility tests were performed on the coating compositions (3) and (4) obtained in Example 2 and Comparative Example 2, respectively.
First, the coating composition was applied to an aluminum plate having a thickness of 0.5 mm to form a coated plate. The coating was performed with a bar coater having a solution film thickness of 55 μm, and the film thickness after drying was 24 ± 1 μm.
Using an automatic discharge dryer manufactured by Nippon Test Panel, the coated plate formed above is baked under heating conditions (set temperature 300 ° C.) so that the maximum temperature after 60 seconds is 260 ° C. It was visually confirmed whether or not this occurred.
As a result, no foam marks were formed in any of the coating compositions (3) and (4).

From the results of Table 1, the coating composition (1) containing a fluorine-containing copolymer composition using an aromatic hydrocarbon mixture (B) having a naphthalene content of 1% or less has a naphthalene content of more than 1%. The dilution rate was improved in the dilution test as compared with the coating composition (2) containing the fluorinated copolymer composition using the aromatic hydrocarbon mixture. Further, in the storage stability test, the initial molecular weights (Mw) of both were almost the same, but the increase in molecular weight after storage at 50 ° C. was more gradual in the coating composition (1).
In the solvent volatility test, neither coating composition (3) nor (4) has a foaming mark due to rapid heating around a practical film thickness of 24 μm in PCM coating, and it can be said that the coating workability is equally good. .

Claims (2)

(A) One or more monomers selected from (a1) fluoroolefin and (a2) one or more monomers selected from the group consisting of vinyl ether, vinyl ester, propenyl ether and propenyl ester are polymerized. A fluorine-containing copolymer, (B) an aromatic hydrocarbon mixture mainly composed of an aromatic hydrocarbon compound having 9 to 11 carbon atoms, and (C) an organic solvent other than (B) the aromatic hydrocarbon mixture. A fluorine-containing copolymer composition comprising:
(B) The fluorine-containing copolymer composition, wherein the amount of naphthalene contained in the aromatic hydrocarbon mixture is 1% by mass or less. A coating composition containing the fluorine-containing copolymer composition according to claim 1.