JP2977742B2 - Polyester resin powder coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin powder coating excellent in oil stain resistance.

[0002]

2. Description of the Related Art Epoxy resin, acrylic resin, polyester resin, epoxy resin / polyester resin powder coatings, etc. are known as thermosetting powder coatings. Body paints, especially powder coatings composed of polyester resins whose isocyanate-cured terminals mainly contain hydroxyl groups (hereinafter referred to as polyester powder coatings) are well-balanced coatings with excellent weather resistance and mechanical strength. It is used in various fields as a paint to form. However, coating films formed from these thermosetting powder coatings are easily contaminated with oil and cannot be easily washed. For this reason, products that have a conventional powder coating film, especially kitchen-related parts such as range hoods that are easily oil stained, are coated with paint that forms an easily peelable coating film. Work to peel off the film and repaint, or baked and applied a fluorine-based or silicone-based clear paint on the paint film formed by powder paint,
A coating film resistant to oil contamination was formed. For this reason, using a powder coating has problems such as the necessity of complicated repainting and the necessity of an expensive fluororesin or silicone resin clear coating. For this reason, there has been a demand for the development of a powder coating material which forms a coating film that is resistant to coating film stains, especially oil stains, and can be restored by simple washing.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of powder coatings so far and to provide a powder coating forming a coating film having excellent oil stain resistance.

[0004]

Means for Solving the Problems The present inventors have conducted studies to solve the above-mentioned problems, and as a result, a powder coating containing a polyester resin and a blocked polyisocyanate has a predetermined amount of an OH group-containing polyester-modified dimethyl ester. Polysiloxa
Perfluoroalkyl containing OH group in the polymer chain
Acrylic oligomers with killed-chain microdomain structure
It has been found that the addition of ー can provide a coating film that is resistant to oil stains and can be restored by simple washing. The present invention
This is based on such knowledge. Therefore, the present invention relates to an OH group-containing polyester-modified dimethylpolysiloxane based on 100 parts by weight of a coating resin powder comprising a polyester resin and a blocked polyisocyanate.
Perfluoroalkyl containing OH group in the polymer chain
Acrylic oligomers with killed-chain microdomain structure
Over the it is to provide a polyester resin-based powder coating, characterized in that blended 0.1-5 parts by weight. Hereinafter, the present invention will be described in detail.

The polyester resin used in the present invention is obtained by reacting a carboxylic acid and a polyhydric alcohol by a conventional method, and has a hydroxyl value of 20 to 80 mgKOH / g, preferably 30 to 60 mgKOH / g. Those are preferred. The reason why the hydroxyl value is limited in this way is that if the value is lower than 20 mgKOH / g, it is difficult to obtain sufficient mechanical properties in the coating film.
If it is higher than 80 mgKOH / g, if the amount of the cross-linking agent is added to the amount, the cost will increase significantly, and the improvement of the coating film performance corresponding to the increase cannot be expected.
Examples of the carboxylic acid used here include terephthalic acid, isophthalic acid, phthalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, β-oxypropionic acid, and the like, and examples of polyhydric alcohols. And ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol and the like.

In the present invention, the blocked polyisocyanate used as a crosslinking agent is a solid at room temperature. Examples of the isocyanate include aliphatic, aromatic, and araliphatic diisocyanates, and a polyisocyanate obtained by reacting a low-molecular compound having active hydrogen, by reacting with a blocking agent, by masking It is manufactured and is easy to manufacture. Examples of the diisocyanate used here include tolylene diisocyanate, 4,4'-diphenylmethane isocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 4,4'-methylene bis (cyclohexyl isocyanate), methylcyclohexane diisocyanate, bis (isocyanate Methyl) cyclohexane, isophorone diisocyanate, dimer acid diisocyanate, lysine diisocyanate and the like.

Examples of low molecular weight compounds having active hydrogen include water, ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, ethanolamine, diethanolamine, hexamethylenediamine and the like. There are isocyanurate, uretdione, low molecular weight polyester containing hydroxyl group, polycaprolactone and the like. Specific examples of the blocking agent include alcohols such as methanol, ethanol and benzyl alcohol, phenols such as phenol and crezone, lactams such as caprolactam and butyrolactam, and oximes such as cyclohexanone, oxime and methyl ethyl ketoxime. .

[0008] These blocked isocyanates are
When the softening temperature is 10 ° C to 120 ° C, especially 40 to 100 ° C
Preferably, there is. When the softening temperature is less than 10 ° C,
The powder paint hardens in an environment of room temperature to 40 ° C,
Is not preferred. On the other hand, when the temperature exceeds 120 ° C,
When producing powder coatings, block isocyanates
It becomes difficult to uniformly disperse
Performance such as film smoothness, coating film strength, and moisture resistance is impaired.
These blocked polyisocyanates are
0.05 to 1.5 equivalents of isocyanate group to hydroxyl group of fat
It is preferred that the compounding agent be used in an amount of 0.8 to 1.2 equivalents.
New This limitation is due to the isocyanate group being 0.1.
If the amount is less than 05 equivalents, the degree of curing of the paint is insufficient, and the adhesion,
The coating film performance such as coating film hardness and chemical resistance decreases, and 1.5 equivalents
If the pressure exceeds the limit, the coating film becomes brittle, and
Heat resistance, chemical resistance, moisture resistance, etc.
In addition, the block isocyanate itself is expensive.
This is disadvantageous in terms of cost. Used in the present invention
ToOH group-containing polyester-modified dimethylpolysiloxane and
And / or perfluoroalkyl containing an OH group in the polymer chain
Acrylic oligomer having chain microdomain structure
Has an OH group in the polymer chain and can be cured with a crosslinking agent.
If it can be used, it can be used without particular limitation.
Especially used in the present inventionOH group-containing polyester modified dimethyl
The polysiloxane is represented by the following general formula (I).

[0009]

Embedded image

(Where x is an integer of 0 to 4 and n is 0
Represents an integer of ~ 3. ) Also, the polymer chains used in the present invention
Of perfluoroalkyl chains containing OH groups
Examples of acrylic oligomers having an acrylic structure include:
EFENSAMCF312 [manufactured by Dainippon Ink and Chemicals, Inc.
Product name; OH value / solid content 59] . The polyester powder coating of the present invention, the polyester resin and the block polyisocyanate as a binder, a coloring pigment, extender pigment, 100 parts by weight of the coating resin powder containing other additives, the OH group-containing polyester modified dimethyl. Poly
Perfume containing OH groups in siloxane and / or polymer chains
Acrylic with microdomain structure of oloalkyl chain
The oligomer is blended in an amount of 0.1 to 5 parts by weight, preferably 0.2 to 2 parts by weight, melt-blended, and the resulting mass is pulverized and then classified. The reason why the amount of the additive is limited as described above is that if the amount is less than 0.1 part by weight, there is a problem in persistence of oil stain resistance. This is because the stability of the powder coating material is impaired, such as bleeding out or blocking. Further, the average particle size of the powder coating is 10 to 6
It is suitable that the thickness is 0 μm, preferably 15 to 45 μm.

Examples of pigments used for the powder coating include titanium dioxide, red iron oxide, iron oxide, carbon black, phthalocyanine blue, phthalocyanine green, quinacridone pigments, azo pigments and isoindolinone pigments. There are extenders such as coloring pigments, silica, talc, precipitated barium sulfate, and calcium carbonate. In addition, as other additives, a leveling agent, an antistatic agent,
An ultraviolet absorber, an anti-sagging agent, a surface conditioner, a crosslinking accelerating catalyst, a defoaming agent, and the like can be used, and various modified resins such as a polyester resin and an acrylic resin can be added.

The polyester powder coating composition of the present invention contains 40 to 60 parts by weight of a polyester resin, preferably 50 to 55 parts by weight, 5 to 25 parts by weight of a block polyisocyanate, preferably 10 to 15 parts by weight, and 20 to 40 parts by weight of a pigment. Parts, preferably 30 to 35 parts by weight of the resin powder 10 for paint.
0 parts by weight of OH-containing polyester-modified dimethyl ester
Polysiloxane and / or perf containing OH group in polymer chain
Acrylic with microdomain structure of fluoroalkyl chain
0.1-5 parts by weight of Le oligomer, preferably, 0.2 to 2
Mix by weight. If the amount of the additive is less than 0.1 part by weight, there is a problem in the persistence of stain resistance. If the amount exceeds 5 parts by weight, the bleed out of these additives becomes remarkable,
It is not preferable because the stability of the powder coating such as blocking is impaired.

[0013]

According to the present invention, there is provided a powder coating which has a sustained oil repellency and provides a coating film resistant to oil stains while maintaining the performance of the conventional polyester powder coating.

[0014]

The present invention will be described in more detail with reference to the following examples. In the examples, “parts” and “%” are shown on a weight basis. (Examples 1 to 8 and Comparative Examples 1 to 6) Mixtures having the compositions shown in Tables 1 and 2 were melt-kneaded using a biaxial kneader, and the resulting mixture was cooled and solidified, and then pulverized. Separation was performed with a mesh wire net to obtain a powder coating. The obtained powder coating was electrostatically coated on a zinc phosphate treated plate so that the film thickness became 50 to 60 μm, and baked at 180 ° C. for 20 minutes to evaluate its physical properties. Table 1 shows the results.

[0015]

[Table 1] Table 1 ────────────────────────────────── Example 1 2 3 4 5 6 7 8 9 Polyester resin A Note 1) A ₁₎ A ₁₎ B ₂₎ C ₃₎ D ₄₎ E ₅₎ F ₆₎ G ₇₎ A ₁ Polyester resin B Note 2) 53 53 47 52 55 55 53 53 55 53 Hard Reagent 8) 11 11 18 9 9 10 11 10 11 Leveling agent 9) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Benzoin 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Silicone additive 10) 0.5 3.5 2.0 1.5 1.7 1.3 Fluorine Additive a 11) 1.0 1.3 0.7 1.5 2.5 4.0 Fluorine additive b 12) Titanium dioxide 35 35 35 35 35 35 35 35 35 Oil pollution test 〇 〇 〇 〇 〇 〇 〇 〇 〇 ──────── ────────────────────────────

[0016]

[Table 2] Table 2 Comparative Example 1 2 3 4 5 6 Hardening agent Note 8) 11 11 9 11 11 9 Leveling agent Note 9) 0.5 0.5 0.5 0.5 0.5 0.5 Benzoin 0.2 0.2 0.2 0.2 0.2 0.2 Silicone additive Note 10) 0.07 6.0 6.0 Fluorine additive a Note 11) 1.5 7.0 Fluorine additive b Note 12) 3.5 Titanium dioxide 35 35 35 35 35 35 35試 験 Oil contamination test △ × △ △ × × ────────────────────────────────────

Note 1) GV710 [trade name, manufactured by Yupika Japan Ltd .; hydroxyl value 43 mgKOH / g, Tg 55 ° C, weight average molecular weight 11,500] Note 2) GV746 [trade name, manufactured by Yupika Japan Co., Ltd .; hydroxyl value 7]
6 mg KOH / g, Tg 60 ° C., weight average molecular weight 19,500] Note 3) GV150 (trade name, manufactured by Nippon Yupika Ltd .; hydroxyl value 4)
3 mg KOH / g, Tg 59 ° C., weight average molecular weight 18000] Note 4) ER6800 [trade name, manufactured by Nippon Ester; hydroxyl value 32 mg KOH / g, Tg 55 ° C.] Note 5) ER6550 [trade name, manufactured by Nippon Ester; hydroxyl value 40 mg KOH / g, Tg 53 ° C,]

Note 6) M8076 [manufactured by Dainippon Ink and Chemicals; hydroxyl value 43 mgKOH / g, Tg 63 ° C, weight average molecular weight 13000] Note7) M8050 [manufactured by Dainippon Ink and Chemicals; hydroxyl value 40 mgKOH / g, Tg62] ° C, weight average molecular weight 1600
0) Note 8) B1530 [manufactured by Hulls; ε-caprolatum adduct of isophorone diisocyanate, softening point 85 ° C] Note 9) PF85 [manufactured by Kyoeisha Chemical Co., Ltd .; organic copolymer]

Note 10) BYK370 (trade name of BYK Japan KK; OH value (active ingredient) about 35) Note 11) DEFENSA MCF312 [trade name of Dainippon Ink and Chemicals, OH value / solids 59] Note 12 ) Lubron L2, L5 [trade names manufactured by Daikin Industries;
Low-molecular-weight tetrafluorinated ethylene resin] <Oil contamination test> The coating film was brush-painted with oil usually used in a home kitchen, and visually judged. 〇: Even if the process of brushing the coating film with oil, wiping with a cloth, further brushing and wiping with a cloth is repeated, there is persistence. Δ: The effect is lost after repeating the above operation three times. ×: An oil film is formed after one application.

From the results shown in Tables 1 and 2, Examples 1 to 9, which are the polyester powder coatings of the present invention, show good oil stainability,
In Comparative Example 1 in which the amount of methylpolysiloxane added was small, the oil contamination was slightly poor and an oil film was formed after repeating twice. OH
In Comparative Example 2 in which the amount of addition of the group-containing polyester-modified dimethylpolysiloxane was excessive, the oil stainability was poor, and the coating properties such as leveling properties were also deteriorated. Polyester modified with OH group
Methyl polysiloxane and par containing OH group in polymer chain
An agent having a microdomain structure of a fluoroalkyl chain
Comparative Example 3 in which the amount of the mixture of the ril oligomer was excessive was
Oil contamination is rather poor and an oil slick is formed after repeating three times.
Comparative Example 5 containing a fluorine-containing additive containing no hydroxyl group
Has poor oil pollution and has no effect. Comparative Example 6, in which no additive was added, had poor oil contamination and immediately formed an oil film.

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C09D 183/06 C09D 183/06 (56) References JP-A-51-151728 (JP, A) JP-A-51-24630 (JP, A) JP-A-4-359972 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09D 5/03 C09D 167/02

Claims (1)

(57) [Claims] 1. An OH group-containing polyester-modified dimethylpolysiloxane is based on 100 parts by weight of a coating resin powder comprising a polyester resin and a blocked polyisocyanate.
And / or perfluoroalkyl containing an OH group in the polymer chain
A polyester resin-based powder coating, comprising 0.1 to 5 parts by weight of an acrylic oligomer having a micro-chain structure of a mono-chain .