JPS587676B2 - Polyester resin composition for powder coatings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester resin composition for powder coatings.

Powder coatings are non-polluting and resource-saving compared to solvent-based coatings, and can be coated up to a thickness of about 100μ in one coat, making it possible to simplify the process and improve future prospects. is expected to develop.

However, in the case of powder coatings, the melting of the powder coating, the smoothing of the coating film, and the curing reaction proceed almost simultaneously when the coating is baked. A serious problem occurs.

Although these problems can be alleviated to some extent by the selection of curing agents, the selection of additives becomes an extremely important issue in order to obtain surface smoothness comparable to that of solvent-based paints. .

Conventionally, additives for powder coatings include acrylic additives (for example, Japanese Patent Publication No. 51-3 96 5 8) and silicone additives (for example, Japanese Patent Publication No. 51-24 No. 1983).
530, JP-A No. 51-80333), but these additives have little effect on preventing "repellency" on the painted surface, and some curing agents may reduce the smoothness of the painted film. There was a problem with the large cloth being damaged, and there was a strong demand for a solution to that problem.

冫 As a result of intensive research to solve the problem, the inventors of the present invention found that
If polydimethylsiloxane and/or polymethylphenylsiloxane and a nonionic surfactant are used together as additives, the coating film will have excellent smoothness regardless of the combination with any curing agent, and will not cause repelling. We have found that this does not occur and have arrived at the present invention.

That is, in the present invention, 0.00 parts by weight of polydimethylsiloxane or/and polymethylphenylsiloxane is added to 100 parts by weight of a saturated polyester resin having a softening point of 50 to 200°C.
01-5 parts by weight and nonionic surfactant 0.00
This is a resin composition for powder coating containing 5 to 5 parts by weight.

In order to obtain the saturated polyester resin used in the present invention, it is manufactured by reacting a carboxylic acid component and a polyol component by a known method.The carboxylic acid component used here includes phthalic acid (anhydride), Isophthalic acid, terephthalic acid, (anhydrous) tetrahydrophthalic acid, (anhydrous) hexahydrophthalic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecane dinorboxic acid, dimer acid, trimellitic acid, trimesine Acids, pyromellitic acid, P-oxybenzoic acid, or functional derivatives thereof can be mentioned, and polyol components include ethylene glycol, propylene glycol, ■・3-propanediodel, 1,4-butanediol, ■・5-pentanediol, ■・6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, hydrogenated bisphenol A, cyclohexanedimethanol, ethylene oxide adduct of bisphenol λ, and propylene oxide Adducts such as ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like can be mentioned.

In particular, it is preferable to use terephthalic acid as the carboxylic acid component.

The saturated polyester resin used in the present invention needs to have a softening point in the range of 55°C to 200°C, preferably 60°C to 150°C, and the composition ratio of the carboxylic acid component and the polyol component is such that the softening point is within the range of the present invention. selected to fall within the range.

Powder-free compositions obtained from polyester resins with a softening point of less than 50° C. have poor blocking resistance, tend to clump together, and have poor powder coating properties, making them unsuitable for practical use.

Further, powder compositions obtained from polyester resins having a soft point exceeding 200° C. have poor flowability of coating films, and cannot provide smooth coating films.

Two or more types of polyester resins of the present invention can be used in combination.

The polydimethylsiloxane or/and polymethylphenylsiloxane used in the present invention has a methyl group (
The ratio of Me ) and phenyl group (Ph) is [Me]/[
Ph]=100-40/0-60 is preferable.

If the ratio of methyl groups is less than 40 mol %, the smoothing effect on the coated surface will not be sufficient, and the hardness of the coated surface will further decrease, making the coated surface more likely to be scratched.

Examples of the polydimethylsiloxane and polymethylphenylsiloxane used in the present invention include TSF-451, TSF-453, and TSF-451 manufactured by Toshiba Silicon ■.
-465,TSF-4 3 1,TSF-433,T
SF-437, TSF-400, TSF-401, etc., KF-96, KF-69, KF-9 manufactured by Shin-Etsu Chemical Co., Ltd.
2, KF-9 9, KF-50, KF-54, KF
-56, KF-961, KF-410, etc., Takemoto Oil ■
B-96-(A-.-G), B-96-P,
Linear polydimethylsiloxane or polymethylphenylsiloxane such as B-9 6-u, or cyclic polymethylphenylsiloxane such as SH6018 manufactured by Toray Silicon ■, or YR73 manufactured by Toshiba Silicon ■.
Branched polymethylphenylsiloxanes such as 168 and the like can be mentioned.

These polydimethylsiloxanes and polymethylphenylsiloxanes can be used alone, or two or more types can be used in combination if necessary.

The amount of polydimethylsiloxane or/and polymethylphenylsiloxane used in the present invention is 1 part for polyester resin.
It is preferably used in a range of 0.01 to 5 parts by weight, preferably in a range of 0.1 to 1 part by weight.

Paint films formed from powder paints in which the amount used is less than 0.01 parts by weight are susceptible to paint film defects such as "repellent".
The smoothness of the coated surface is also poor, making it impossible to achieve the object of the present invention.

In addition, powder coatings in which the amount used exceeds 5 parts by weight are outside the limit of compatibility between polyester resin and organic silicon compounds, resulting in undesirable coating films that are sticky and have poor coating properties. .

Nonionic surfactants used in the present invention include (+)holJ1 ethylene glycol monomethyl ether,
Polyethylene glycol monoethyl ether, polyethylene glycol mono n-propyl ether, polyethylene glycol mono n-butyl ether, polyethylene glycol mono n-pentyl ether, polyethylene glycol mono n-hexyl ether, polyethylene glycol monooctyl ether, Polyethylene glycol monodecyl ether, polyethylene glycol monolauryl ether, polyethylene glycol monotritecyl ether, polyethylene glycol monocetyl ether, polyethylene glycol monostearyl ether, polyethylene glycol monooleyl ether, polyethylene glycol dimethyl ether, polyethylene glycol Diethyl ether, polyethylene glycol di-n-propyl ether, polyethylene glycol di-n-butyl ether, polyethylene glycol di-n
-Pentyl ether, HoIJ ethylene glycol di-n
monohexyl ether, polyethylene glycol di-n
- Ethylene glycol mono- or dialkyl ethers such as octyl ether, polyethylene glycol didecyl ether, polyethylene glycol dilauryl ether, polyethylene glycol distearyl ether, (++) polyethylene glycol mono(octyl phenyl) ether, polyethylene glycol- mono(
Nonyl phenyl) ether, polyethylene glycol
Mono(tethylphenyl) ether, polyethylene glycol-mono(dodecylphenyl) ether, polyethylene glycol-mono(p-cumyl phenyl) ether, polyethylene glycol-mono(methylphenyl) ether, polyethylene glycol-mono(ethyl phenyl) ether, etc. mono(alkylaryl)ethers of polyethylene glycol, (iii) polyethylene glycol monoacetate, polyethylene glycol diacetate, polyethylene glycol monopropionate, polyethylene glycol dipropionate, polyethylene glycol monoacrylate, polyethylene glycol diacrylate, polyethylene Glycol monomethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol monocaproate, polyethylene glycol dicaproate, polyethylene glycol monooctanoate, polyethylene glycol dioctanoate, polyethylene glycol monodecanoate, polyethylene glycol didecanoate, polyethylene Glycol monolaurate, polyethylene glycol dilaurate, polyethylene glycol monomyristate, polyethylene glycol dimyristate, polyethylene glycol monopalmitate, polyethylene glycol dipalmitate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monomyristate Mono- or di-fatty acid esters of polyethylene glycol, such as oleate, polyethylene glycol dioleate, polyethylene glycol monoricinolate, polyethylene glycol silicinoleate, polyethylene glycol monoercarate, polyethylene glycol dielkalate, (IV) Polyethylene glycol methyl ether acetate, polyethylene glycol ethyl ether acetate, polyethylene glycol-n-butyl ether acetate, polyethylene glycol lauryl ether acetate, polyethylene glycol lauryl ether caproate, polyethylene glycol oleyl ether laurate, polyethylene glycol oleyl ether stearate, Polyethylene glycol stearyl ether stearate, polyethylene glycol stearyl ether laurate, polyethylene glycol lauryl ether benzoate, polyethylene glycol (
octylphenyl) ether laurate, polyethylene glycol (octylphenyl) ether oleate,
Polyethylene glycol (nonylphenyl) ether laurate, polyethylene glycol (nonylphenyl)
Ether oleate, polyethylene glycol (nonylphenyl) ether stearate, polyethylene glycol (dodecyl phenyl) ether laurate, PoIJ
-I- f Fatty acid esters of polyethylene glycol (monoalkyl or monoalkylaryl) ethers such as glycol (dodecylphenyl) ether oleate, (V) polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan dilaurate, polyoxyethylene Ethylene sorbitan trilaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan distearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan dioleate, polyoxyethylene sorbitan Fatty acid esters of polyoxyethylene sorbitan such as trioleate, (VO polyoxyethylene trimethylol propane monooleate, polyoxyethylene trimethylol propane dilaurate, polyoxyethylene trimethylol propane monourarate, polyoxyethylene trimethylol propane dilaurate) , polyoxyethylene pentaerythritol monostearate, polyoxyethylene pentaerythritol distearate, polyoxyethylene pentaerythritol tristearate, polyoxyethylene pentaerythritol monolaurate, polyoxyethylene pentaerythritol dilaurate, polyoxyethylene penta Erythritol trilaurate, polyoxyethylene pentaerythritol monooleate, polyoxyethylene pentaerythritol dioleate, polyoxyethylene pentaerythritol trioleate, polyoxyethylene sorbitol monolaurate, polyoxyethylene sorbitol dilaurate, polyoxyethylene sorbitol trioleate Laurate, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol distearate, polyoxyethylene sorbitol tristearate, polyoxyethylene sorbitol monooleate, polyoxyethylene sorbitol dioleate, polyoxy Alkylene oxide adducts of fatty acid esters of trihydric or higher polyhydric alcohols such as ethylene sorbitol trioleate, 6/iDHoIJ (ethylene-propylene) glycol monomethyl ether, poly(ethylene-propyrescine) glycol monon=- 7''thyl ether, poly(ethylene-propylene) fIJ colmono n-hexyl ether, poly(ethylene-propylene) glycol monolauryl ether, poly(ethylene-propylene) glycol monoce. Thyl ether, holi(ethylene-propylene) glycol monooleyl ether, poly(ethylene-propylene) glycol monostearyl ether, holi(ethylene-propylene) glycol diethyl ether, holi(ethylene-propylene) glycol dipropyl ether, holi(ethylene-propylene) propylene) glycol di-pentyl ether, poly(ethylene-propylene) glycol dioctyl ether, poly(ethylene-propylene) glycol cytotecyl ether, poly(ethylene-propylene) glycol cytotecyl ether,
Poly(ethylene-propylene) glycol mono- or dialkyl ethers such as holi(ethylene-propylene) glycol dicetyl ether, poly(ethylene-propylene) glycol distearyl ether, hoIJ (ethylene-propylene) glycol dioleyl ether, Qtt > Poly(ethylene-propylene) glycol monoacetate, poly(ethylene-propylene) glycol diacetate, poly(ethylene-propylene) glycol monopropionate, poly(ethylene-propylene) glycol diacrylate, poly(ethylene-propylene) Glycol monomethacrylate, poly(ethylene-propylene) glycol monocaproate, poly(ethylene-propylene) glycol dioctanoate, poly(ethylene-propylene) glycol monodecanoate, poly(ethylene-propylene) Glycol monolaurate, poly(ethylene-propylene) glycol monomyristate, poly(ethylene-propylene) glycol dipalmitate, poly(ethylene-propylene)
Glycol monostearate, poly(ethylene-propylene) glycol distearate, poly(ethylene-propylene) Krypyl monooleate, poly(ethylene-propylene) glycol geosort, poly(ethylene-propylene) glycol monolylenolate, poly(ethylene-propylene) Mono- or di-fatty acid esters of poly(ethylene-propylene) glycol such as -propylene) glycol dielkalate, as well as (■) polyethylene glycols, (■) polyethylene polypropylene block copolymers, and (■■) polyglopylene. It broadly includes glycols and the like.

The molecular weight used is 300 to 15,000.

The above compounds are exemplified as representative examples, and of course are not limited to these.

Two or more of these compounds can also be used in combination.

The amount of the nonionic surfactant used in combination with the polydimethylsiloxane and/or polymethylphenylsiloxane of the present invention is 0.005 to 5 parts by weight, preferably 0.02 to 0.0 parts by weight, based on 100 parts by weight of the polyester resin. It is preferable to use it in a range of .5 parts by weight.

Coatings formed from powder coatings in which the amount of nonionic surfactant used is outside the range of 0.005 to 5 parts by weight are prone to coating defects such as "repellency" and the smoothness of the coated surface is affected. Unfortunately, the purpose of the present invention cannot be achieved.

The method of adding polydimethylsiloxane or/and polymethylphenylsiloxane (2) and nonionic surfactant (3) to polyester resin (1) is (2).
) and (3) can be added individually, but it is preferable to uniformly mix (2) and (3) in advance before adding them to the polyester resin.

Although they can be added by dispersing and mixing them in granular form while cold, it is preferable to mix them by heating at a temperature higher than the melting temperature of the polyester resin (1).

The obtained mixture is cooled and solidified, and then pulverized to obtain a powdered resin composition.

Pigments, fillers, modifiers, etc. can be added to the resin composition of the present invention, if necessary.

Examples of pigments include titanium oxide, carbon black,
Common organic and inorganic pigments such as iron oxide, aluminum powder, phthalocyanine blue, and phthalocyanine green can be used.

When improving the adhesion, chemical resistance, processability, etc. of the coating film formed from the resin composition of the present invention, the modifier is used in the range of 5 to 200 parts by weight per 100 parts by weight of the polyester resin. One or more compounds that react with polyester resins such as aminoplast resin block polyisocyanate compounds, acid anhydrides, and epoxy resins may be blended.

Among these modifiers, examples of the aminoplast resin include methyl etherified melamine resin, butyl etherified melamine resin, methyl etherified penzoguanamine resin, and butyl etherified penzoguanamine resin.

Blocked polyisocyanate compounds include compounds obtained by blocking known polyisocyanate compounds with active hydrogen-containing compounds, such as tetramethylene diisocyanate, hexamethylene diisocyanate, ω・ω'-diisocyanate dimethylcyclohexane, dicyclohexylmethane diisocyanate, and 3-isocyanate. Polyisocyanate compounds such as methyl-3,5,5-trimethylcyclohexyl isocyanate, or compounds obtained by chain-extending these polyisocyanate compounds with ethylene glycol, trimethylolpropane, etc., such as phenol, metacresol, p-phenylphenol, p-phenylphenol,
- Phenols such as oxybenzoate, oximes such as acetoxime, methyl ethyl ketone oxime, and acetophenone oxime, carbonyl group-containing compounds such as acetylacetone and acetoacetate, alcohols such as methanol, ethanol, and furopanol, ε-cabrolactam, etc. Examples include compounds blocked with an active hydrogen-containing compound.

Examples of the acid anhydride include pyromellitic anhydride, penzophenonetetracarboxylic anhydride, ethylene glycol bistrimelitate, and the like.

As an epoxy resin, for example, Epicoat 11001
, Epicote 1004, Epicote 1007, Epicote 1009 (manufactured by Shell Chemical Co., Ltd.), p-oxybenzoic acid grindyl ester ether, triglycidyl isocyanurate, terephthalic acid diglycidyl ester, inphthalic acid diglycidyl ester, etc. .

The composition of the present invention comprising a polyester resin, polydimethylsiloxane and/or polymethylphenylsiloxane, and a nonionic surfactant is blended with the above-mentioned modifier and/or pigment as necessary, and then heat rolled, extruded, etc. A powder coating composition can be obtained by mixing using a known mixing device and then pulverizing the mixture.

The obtained powder coating composition is coated by a powder coating method, such as an electrostatic coating method or a fluidized dipping method, and then heated at 100 to 250°C, preferably 150 to 220°C.
By performing the heat treatment for 0 to 60 minutes, it is possible to form a coating film that is free from coating film defects such as pinholes and "bumps" and has excellent coating surface smoothness.

The present invention will be explained in more detail with reference to Examples below.

In the examples, parts indicate parts by weight.

The softening point was determined using a fully automatic melting point measuring device (METTLER M).
Measured by ODEL FP=1), the acid value is 0.3 for the resin.
~0.41 was collected and dissolved in 20 ml of chloroform, and then 0.41 was collected using phenolphthalene as an indicator. INK
Measured by titration with OH-MeOH.

Coating film defects such as "cissing" and pinholes, and the smoothness of the coated surface were visually judged.

The Erichsen value is determined by the JIS-z-2247 method, and the impact value is determined by JIS-K5400 ((1.2)" x 500gr.
).

Production Example 1 582 parts of dimethyl terephthalate and 3 parts of dimethyl isophthalate were placed in a reaction vessel equipped with a thermometer, a stirring device, and a cooling tube.
40 parts, trimethylolpropane 34 parts, ethylene glycol 651 and zinc acetate 0.44 parts,
After carrying out the transesterification reaction at 0°C to 220°C for 3 hours,
Gradually reduce the pressure to 0. 5 ~ 0. 1 miHg 2 5
A polycondensation reaction was carried out at 0°C for 30 minutes to form a polyester resin (
A) was obtained.

The softening point of the polyester resin (8) is 85°C, and the acid value is 0.
It was 8.

Production Example 2 In a stainless steel autoclave equipped with a thermometer, a stirring device, and a cooling tube, 415 parts of terephthalic acid, 400 parts of glopylene glycol, and dibutyltin oxide Q. 5 parts and heated at 230°C under a pressure of 3 kg/crA (gauge pressure).
The reaction was carried out at ~240°C for 3 hours.

Next, 315 parts of terephthalic acid and 50 parts of sebacic acid were added and reacted at 200°C to 250°C for 12 hours. Furthermore, 67 parts of trimellitic anhydride was added and reacted at 230°C to 240°C for 1 hour to form the polyester resin (B). Obtained.

The softening point of the polyester resin (B) is 98°C and the acid value is 50
Met.

Example 1 1000 parts of polyester resin (A), 80 parts of pyromellitic anhydride, 4.4 parts of polydimethylsiloxane KF-96 (manufactured by Shin-Etsu Chemical Co., Ltd.), poly(ethylene-propylene)
Monooleate molecular weight 36,000.6 parts and titanium oxide (R-930 manufactured by Ishihara Sangyo ■) 400 parts were roughly combined in a Henschel mixer, and then mixed at 100°C to 13°C using a twin screw extruder.
Melt mixing was performed at 0°C.

After cooling, the powder was pulverized with a Hosokawa fine grinder, swirled through a 100-mesh sieve, and the powder was sieved.

Run the obtained powder coating. After coating on a mild steel plate (TISG-3 1 4 1) using an electrostatic powder coating machine manufactured by Zuberg to a film thickness of 50 to 70μ, 210'
Baking was performed for 0.020 minutes.

The performance of the resulting coating film is shown in Table 2.

Examples 2 to 4 Powder coatings were produced using the formulations shown in Table 1 in the same manner as in Example 1, and were painted and baked.

The performance of the resulting coating film is shown in Table 2.

Comparative Examples 1 to 3 Powder coatings were produced using the formulations shown in Table 1 in the same manner as in Example 1, and were painted and baked.

The performance of the resulting coating film is shown in Table 2.

As is clear from Table 2, when using polydimethylsiloxane and/or polymethylphenylsiloxane alone or nonionic surfactants alone, "repellency" and pinholes occur, and the smoothness of the coated surface is poor. Therefore, when these compounds are used in combination, these drawbacks can be improved.

Claims (1)

[Claims] 1 Saturated polyester resin with a softening point of 50 to 200°C 10
0 parts by weight of polydimethylsiloxane and/or polymethylphenylsiloxane. Ol ~ 5% by weight
and a polyester resin composition for powder coating, which contains 0.005 to 5 parts by weight of a nonionic surfactant.