JP3287878B2 - Resin composition for paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of mixing a lactone-modified acrylic resin having undergone lactone modification with a hydroxyl group-containing fluororesin, further blending a curing agent which reacts with these hydroxyl groups, and curing by heating or at room temperature. The weather resistance, water resistance, stain resistance, solvent resistance, chemical resistance, transparency,
The present invention relates to a resin composition for a paint capable of obtaining a coating film having excellent gloss, flexibility, hardness, workability, and the like.

[0002]

2. Description of the Related Art Conventionally, it is known that a curing agent is blended with a hydroxyl group-containing fluororesin to obtain a paint having excellent weather resistance. However, commercially available hydroxyl group-containing fluororesin is expensive.
The cured film has the drawback that it is easily stained and has poor workability (bendability). Furthermore, the compatibility with other resins is poor, so that at present the modification by blending cannot be neglected. Several methods have been proposed to remedy such disadvantages. For example, see JP-A-59-197471.
In the publication, an acrylic copolymer containing a (meth) acrylate ester having a long-chain alkyl group in the side chain having at least 10 carbon atoms as an essential component is mixed with a hydroxyl group-containing fluororesin, and further a curing agent is compounded. To obtain a coating film by heat curing. This is because the glass transition temperature of the long-chain (meth) acrylate used as an essential component to increase the compatibility is too low, and is insufficient in terms of hardness, drying properties, stain resistance, and solvent resistance. The results have not been successful and cannot be said to be successful. Also, Japanese Patent Application Laid-Open No. Sho 62-2
No. 12471 discloses that an acrylic resin containing n-butyl methacrylate, isobutyl methacrylate, or ter-butyl methacrylate as an essential component is mixed with a hydroxyl group-containing fluororesin, and a cured coating film is obtained in the same manner as described above. Is disclosed. This has the advantage of increasing the hardness of the coating film by using these butyl methacrylate monomers, but causes a decrease in compatibility with the fluororesin. Therefore, there is a disadvantage that the range of use is extremely limited because the mixing ratio of both resins is limited.

[0003]

The present inventors have conducted intensive studies in order to solve the above-mentioned drawbacks of the prior art.
That the hydroxyl group-containing acrylic resin to which the lactone having 3 to 8 carbon atoms is added shows compatibility with the hydroxyl group-containing fluororesin,
In particular, by adjusting the hydroxyl value of the acrylic resin to 5 to 100 and the weight average molecular weight (Mw) to 5,000 to 300,000, it becomes possible to make the acrylic resins compatible with each other in the entire mixing amount range, and to further incorporate a curing agent The cured coatings can also obtain a wide range of performance, are excellent in weather resistance, stain resistance, solvent resistance, transparency, gloss, hardness, flexibility, workability, etc., and are inexpensive. The inventors have found that a film can be formed, and have reached the present invention.

[0004]

That is, the present invention relates to a fluororesin (A) having 5 to 95% by weight of a hydroxyl group-containing fluororesin, which is addition-modified with a lactone having 3 to 8 carbon atoms in a ring, and has a hydroxyl value of 5 to 100. Having a weight average molecular weight of 5,000 to 300,0
(Meth) acrylic resin (B) is 95 to 5% by weight
(The total of (A) and (B) is 100% by weight) and a curing agent (C) capable of reacting with the hydroxyl groups of (A) and (B) to form a cured film. It is a characteristic resin composition for paints. Hereinafter, the hydroxyl group-containing fluororesin (A), the (meth) acrylic resin (B) and the curing agent (C) constituting the composition of the present invention will be described in order.

As the hydroxyl group-containing fluororesin (A) constituting the composition of the present invention, for example, JP-A-57-34107
JP, JP-A-59-102961, JP-A-61-102961
No. 101577, vinylidene fluoride, tetrafluoroethylene, trifluoroethylene,
Chlorotrifluoroethylene, hexafluoropropylene,
Fluorine-containing copolymerizable monomers such as 2-perfluorobutylethyl methacrylate and n-butylchlorotrifluorovinyl ether, and hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, 2-hydroxyethyl (meth) acrylate, and 2-hydroxy Propyl (meth) acrylate, a compound in which ε-caprolactone is added to 2-hydroxyethyl (meth) acrylate, a hydroxyl group-containing compound such as allyl cellosolve, glycerin monoallyl ether, or a lactone adduct of the allyl ether with a hydroxyl group. Polymerizable monomers, or ethyl vinyl ether, propyl vinyl ether, ethylene, styrene,
Methyl (meth) acrylate, dibutyl fumarate, diethyl malate, itaconic acid, dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl esters of long-chain tertiary fatty acids A resin obtained by appropriately copolymerizing a general-purpose copolymerizable monomer such as a vinyl ester of an aliphatic monocarboxylic acid such as a vinyl ester of a fatty acid such as vinyl ester of a benzoic acid such as a vinyl ester of a fatty acid (for example, a product name of Ciel, Inc.). is there. Examples of commercially available products of such a resin include, for example, Lumiflon LF- manufactured by Asahi Glass Co., Ltd.
100, LF-200, LF-400, LF502, L
F-504 and the like.

The (meth) acrylic resin (B) to which the lactone constituting the composition of the present invention has been added is prepared by, for example, adding 1 to 10 mol of ε-caprolactone to 2-hydroxyethyl (meth) acrylate using a catalyst. Hydroxyl-containing copolymerizable monomers and other copolymerizable monomers, for example, copolymerizable olefins such as ethylene, propylene, styrene, butadiene, N-vinylpyrrolidone, and vinylpyridine, or methyl (meth) acrylate, ethyl (meth) ) Acrylate, propyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth)
Acrylate, glycidyl (meth) acrylate, (meth) acrylic acid, N, N-dimethylacrylamide,
Acrylic monomers such as N, N-diethylaminoethyl (meth) acrylate, or dimethylmalate;
Copolymerizable dibasic acids such as diethyl malate, dibutyl fumarate, dimethyl itaconate and maleic anhydride and esters thereof, or vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether, and other N-methyl maleimide, N It is obtained by copolymerization of at least one or more monomers with copolymerizable monomers such as -butylmaleimide, ethylvinylketone, methylvinylsulfide, crotonamide, acrylonitrile, divinylsulfone, and ethylcinnamate. Further, as an example of a lactone compound,
In addition to ε-caprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone and the like can be mentioned. Further, as the (meth) acrylic monomer having a hydroxyl group to be reacted with a lactone, besides 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 3-hydroxybutyl ( Examples thereof include (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, and N-hydroxymethylacrylamide. As such a lactone-modified monomer, for example, Praxel F commercially available from Daicel Chemical Industries, Ltd. can be used.

As a method for synthesizing the (meth) acrylic resin (B) to which lactone has been added, a ring-opening addition of lactone to the above-mentioned hydroxyl-containing acrylic monomer is carried out, and the resulting hydroxyl-containing acrylic monomer is obtained. Can be obtained by copolymerization with acrylonitrile and other copolymerizable monomers.However, the acrylic monomer containing a hydroxyl group is first copolymerized with another copolymerizable monomer, and ring-opening addition of lactone is performed to the obtained hydroxyl group-containing resin. It is also possible to obtain the desired product.

The hydroxyl value of the lactone-added (meth) acrylic resin (B) constituting the present invention must be limited to the range of 5 to 100. When the hydroxyl value is less than 5, a cured film obtained by blending with a curing agent described later is weak, so that the solvent resistance becomes poor and the practicality is lost. When the hydroxyl value is larger than 100, the hydroxyl group-containing fluororesin (A)
Is poor, and a glossy coating film cannot be obtained, and similarly, the practicality is lost.

Further, if the weight average molecular weight of the (meth) acrylic resin (B) component is less than 5,000, the cured film is weak and the solvent resistance is insufficient. In addition, the weight average molecular weight is 300,
If it exceeds 000, the solution viscosity of the resin is too high, so that it is practically impossible to prepare a coating.

Further, the amount of the (meth) acrylic resin (B) used can be basically mixed with the hydroxyl group-containing fluororesin in a free ratio. Therefore, it is not necessary to particularly limit the amount. If the total amount of A) and (meth) acrylic resin (B) is less than 5% by weight based on 100% by weight,
It cannot exhibit the stain resistance, glossiness, and processability that are characteristics of acrylic resin. On the other hand, if the content exceeds 95% by weight, the weather resistance and the chemical resistance, which are the characteristics of the fluororesin, are lost.

Next, the curing agent that can be used in the present invention will be described. The curing agent (C) used in the present invention refers to a compound having a functional group that reacts with the hydroxyl group of the components (A) and (B). For example, an amino compound such as urea, melamine, and guanamine and an aldehyde are used. The product obtained by the addition condensation reaction is treated with methanol, ethanol, propanol, n-butanol, neopentyl glycol,
An alkyl etherified amino resin obtained by etherification with an alcohol such as 6-hexanediol is exemplified.

In the present invention, the mixing ratio of the mixture of the resins (A) and (B) and the alketherified amino resin curing agent (C) is as follows: resin [(A) + (B)] / alketherified amino resin Curing agent (C) = 50-90 / 10
To 50 (weight ratio), preferably 60 to 80/20.
It is particularly preferable to mix them so as to be 40 to 40 (weight ratio). When the amount of the alkyl etherified amino resin curing agent (C) is too large or too small, the coating film performance is significantly reduced.

Other curing agents usable in the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, trimethylhexane diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4-diisocyanate, and 4,4'-methylenebis (cyclohexyl). Isocyanates), or adducts of these diisocyanates with polyhydric alcohols such as ethylene glycol, propylene glycol, polypropylene glycol, and trimethylolpropane; polyester resins having functional groups that react with isocyanate groups; acrylic resins; and water; or Multimer reacted with biuret isocyanate, or lower-valent alcohol, methyl ethyl ketooxy Include those that are blocked by lactams as isocyanate curing agent.

In the present invention, the resin mixture [(A) +
(B)] and the isocyanate-based curing agent (C) in a ratio of OH / NCO = 1 / 0.7 to 1/1 / from the viewpoint of coating film performance.
A range of 1.3 (equivalent ratio) is preferable.

The coating resin composition of the present invention contains the above components (A), (B) and (C) as essential components. If desired, a resin such as an epoxy resin or a polyester resin may be used. Among them, various additives for paint such as a pigment, a dispersant, a leveling agent, an ultraviolet absorber, an antioxidant and a curing accelerator can be blended.

The resin composition for coatings of the present invention thus obtained is usually used for automobiles, automobile repairs, vehicles, general metals, building interiors and exteriors, building materials, plastics, woodwork, home appliances, and the like. According to the method, it can be applied by applying, for example, by spray coating, roller coating, brush coating, dipping, electrodeposition coating, and curing at room temperature or by heating and curing at 40 to 280 ° C. for 1 to 60 minutes.

[0017]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The “parts” in the examples are on a weight basis.

(Production Example 1) Production of (meth) acrylic resin to which lactone was added Xylene 500 was placed in a two-liter four-necked flask equipped with a stirrer, thermometer, dropping funnel, and N ₂ gas introduction tube.
And 2.5 parts of di-tert-butyl peroxide, and the system was sufficiently purged with N ₂ , and then heated. When the temperature reached 110 ° C., ε-caprolactone-modified 2-hydroxyethyl methacrylate (Daicel Chemical Industries, Ltd.) Industrial Co., Ltd. "Placcel FM-1") 150 parts, methyl methacrylate 250 parts, 2-ethylhexyl methacrylate 100
Part of the mixture is slowly added dropwise. After the dropping was completed in 1 hour and the reaction was carried out at the same temperature for 2 hours, 2.5 parts of di-tert-butyl peroxide was newly added and the reaction was further continued for 3 hours to obtain a methacrylic resin having a hydroxyl group. . Table 1 shows the monomer composition, and Table 2 shows the properties of the obtained resin.
In addition, the hydroxyl value in a table | surface is a value with respect to resin solid content.

(Production Example 2) Using the same apparatus as in Production Example 1, 250 parts of toluene, 250 parts of butyl acetate and 2.5 parts of t-butyl peroctoate were charged as solvents.
The temperature inside the system was sufficiently replaced by N ₂ and then the temperature was raised. When the temperature reached 100 ° C., 2-hydroxypropyl methacrylate 70
225 parts of methyl methacrylate and 150 parts of ethyl acrylate were added dropwise at the same temperature over 1 hour. After the completion of the dropwise addition, the reaction was continued for 2 hours, 2.5 parts of t-butyl peroctoate was further added, and the mixture was reacted for 3 hours and then cooled to room temperature. 55 parts of ε-caprolactone was added to this reaction solution,
0.1 parts of stannous chloride was added and reacted at 105 to 110 ° C. for 10 hours to obtain a hydroxyl-containing acrylic resin. The properties of the obtained resin are as shown in Table-2.

(Production Examples 3 to 6) An acrylic resin having the composition shown in Table 1 was produced in the same manner as in Production Example 1. Table 2 shows the properties of the obtained resin.

(Production Examples 7 and 8) In the same manner as in Production Example 1, 70 parts of 2-hydroxyethyl methacrylate, 250 parts of methyl methacrylate, and 180 parts of ethyl acrylate
Thus, a hydroxyl group-containing acrylic resin having the following composition was obtained (Production Example 7). Table 2 shows the properties of the obtained resin. Similarly, a hydroxy group-containing acrylic resin was obtained using 2-hydroxypropyl methacrylate, methyl methacrylate, and n-butyl acrylate in the monomer compositions shown in Table 1 (Production Example 8). The properties of the obtained resin are as described in Table-2.

[0022]

[Table 1]

[Table 2]

(Example 1) 100 parts of the hydroxyl-containing acrylic resin solution (non-volatile concentration: about 50%) obtained in Production Example 1 and 83 parts of a fluororesin solution (Lumiflon LF-200, non-volatile concentration: about 60%) were mixed at room temperature. And mixed well. This mixed solution having a resin content of 5/5 was applied to a transparent glass plate to a thickness of 1 mm using an applicator. After drying at room temperature for one day, the coating film was visually inspected for the presence or absence of dust, and the compatibility was determined. In the same manner, the compatibility was determined by changing the kind of the fluororesin and the mixing ratio of the acrylic resin and the fluororesin as shown in Table-3. The results are shown in Table-3.

(Examples 2 to 6) The acrylic resin and the fluororesins (Lumiflon LF-200 and LF-502 (nonvolatile content: about 40%)) obtained in Production Examples 2 to 6 in the same manner as in Example 1 Compatibility was tested. The results are shown in Table-3.

Comparative Examples 1-2 The fluororesins (Lumiflon L) were prepared in the same manner as in Example 1 using the resins of Production Examples 7 and 8.
F-200 and LF-502).
Comparison was made with Examples 1 to 6. The results are shown in Table-3.

[0026]

[Table 3]

(Examples 7 to 12) An isocyanate-based curing agent (hexamethylene diisocyanate block: Sumitomo Bayer) was added to 100 parts of the mixed resin solid content of the lactone-modified acrylic resin solution and the fluororesin solution obtained in Examples 1 to 6. "Desmodur BL3175") or a melamine-based curing agent ("Cimel 30" manufactured by Mitsui Cyanamid)
3)), a titanium oxide pigment was added in an amount of 50% by weight based on the solid content of the resin, and the mixture was dispersed in a sand mill for 60 minutes. Immediately, a mild steel plate test panel specified by JIS K-5400 was applied using a bar coder. Applied. 1 at room temperature
After drying for an hour, a baked cured film was obtained. The baking conditions are 230 ° C x 60 for baking with an isocyanate-based curing agent.
Second, baking with a melamine-based curing agent was performed at 280 ° C. × 60 seconds. Table 4 shows the mixing ratio of the coating materials, and Table 5 shows the properties of the obtained coating film.

(Comparative Examples 3 to 5) According to the same method as in Example 7, the performance of the cured film was tested using the resin of Comparative Examples 7 to 8 or the fluororesin alone.

[0029]

[Table 4]

[Table 5]

[0030]

As is clear from the results shown in Tables 3 and 5, the coating film obtained from the coating composition of the present invention has properties such as gloss, workability, weather resistance, stain resistance and hardness. It is a well-balanced and excellent paint. Moreover, by using an expensive fluororesin blended with an acrylic resin, the advantage that the economic efficiency can be remarkably enhanced can be exhibited.

Continuation of front page (56) References JP-A-62-212471 (JP, A) JP-A-61-12760 (JP, A) JP-A-61-51045 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) C09D 127/12 C09D 133/14 C09D 201/06

Claims (1)

(57) [Claims] 1. A hydroxyl group-containing fluororesin (A) of 5 to 95% by weight, addition-modified with a lactone having 3 to 8 carbon atoms in the ring, a hydroxyl value of 5 to 100 and a weight average molecular weight of 5,
(Meth) acrylic resin (B) of 95 to 5% by weight (the sum of (A) and (B) is 100
% By weight) and a curing agent (C) capable of forming a cured film by reacting with the hydroxyl groups of (A) and (B).
And a resin composition for a paint.