JPS586749B2 - Polyester materials - Google Patents

Description

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

Powder coatings have many advantages, such as being easier to prevent pollution than solvent-based coatings, being able to coat thickly with one coat of 100μ or more, and being able to collect and reuse the paint. Although it has advantages, it has poor heat flow properties during baking, especially in the case of thermosetting powder coatings.
Currently, they are not as good as solvent-based paints for beautiful painting.

As a result of intensive studies on various additives in order to improve the heat flow properties of polyester resin compositions for powder coatings, the present inventors found that certain polyoxyalkylene monomers were used as additives for polyester resin compositions for powder coatings. When a condensate of an alkyl ether and a polyalkylsiloxane is used, a resin composition with excellent heat flow properties can be obtained;
For this purpose, they discovered that a coating film with excellent gloss comparable to that of solvent-based paints could be obtained, and the present invention was achieved.

That is, the present invention includes 100 parts by weight of a polyester resin having a softening point of 50 to 150°C and/or a resin composition mainly composed of the polyester resin, and a polyoxyalkylene (carbon number: 2 to 8) monoalkyl or alganyl (carbon number: :x~24) Polyester for powder coatings obtained by mixing 0.2~5 parts by weight of a condensate of ether (average degree of polymerization: 1~150) and polyalkyl (carbon number: 1~20) siloxane It is a resin composition.

Examples of the resin composition mainly composed of a polyester resin having a softening point of 50 to 150°C or a polyester resin having a softening point of 50 to 150°C used in the present invention include the following.

(1) A dehydration-curing polyester resin having an acid value of 20 to 200 and a hydroxyl value of 20 to 200, which can be obtained singly or by mixing two or more kinds.

(2) A resin composition comprising a polyester resin having an acid value of 20 to 200 and a compound having two or more oxirane groups in one molecule.

(3) A resin composition comprising a polyester resin having a hydroxyl value of 20 to 200 and an acid value of 4 to 12 and an N-methylol ether compound of melamine such as hexaalkoxymethylmelamine.

(4) A resin composition comprising a polyester resin having a hydroxyl value of 20 to 200 and a blocked isocyanate.

(5) A vinyl curable polyester resin consisting of an unsaturated polyester resin and a curing catalyst.

(6) Thermoplastic polyester resin.

(7) 2 of each of the above polyester resins and resin compositions
species or a mixture of two or more species.

In the present invention, polyoxyalkylene (carbon number:
2-8) Monoalkyl or alkenyl (number of carbon atoms: 1-
24) The amount of the condensate of ether (average degree of polymerization: 1 to 150) and polyalkyl (carbon number: 1 to 20) siloxane (hereinafter abbreviated as condensate) is based on polyester resin or polyester resin. It is appropriate that the amount is 0.2 to 5 parts by weight, preferably 0.5 to 2 parts by weight per 100 parts by weight of the resin composition.

When the amount of the condensate added is 0.2 parts by weight or less, there is almost no effect of adding the condensate. On the other hand, when the amount added is 5 parts by weight or more, the blocking resistance of the resulting polyester resin composition is reduced. It is not suitable because it has poor properties and stability during storage or transportation.

The polyester resin or the polyester resin composition and the condensate can be mixed directly when preparing the resin composition or when forming the paint, or simply when the content of the condensate is relatively low. It is also possible to prepare a large number of masterbatches and mix this masterbatch with the polyester resin or polyester resin composition.

Examples of the condensate used in the present invention include YF
3860 silicone oil (manufactured by Toshiba Silicone, trade name) has extremely favorable performance.

YF3860 silicone oil is included in the condensate referred to in the present invention, and is generally used because it is effective in preventing repellency of solvent-based paints and improving coating workability such as brush painting and spray painting. However, surprisingly, when used as an additive in polyester resin compositions for powder coatings, it has a very remarkable effect on improving the heat flow properties, and the resultant powder coatings have a very significant effect when compared to solvent-based coatings. It is possible to obtain a coating film with an excellent gloss that is comparable to that of the original.

Next, the present invention will be specifically explained by showing examples and reference examples.

Example 1 Dimethyl terephthalate (hereinafter abbreviated as DMT), methyl p-oxyethoxybenzoate (hereinafter abbreviated as OEBM), ethylene glycol (hereinafter abbreviated as EG) and neopentyl glycol (hereinafter abbreviated as NPG) are shown in Table 1. 0.01 mol of zinc acetate was added as a catalyst, and a transesterification reaction was carried out at 150 to 250° C. under normal pressure, and the theoretical amount of methanol was distilled off.

Subsequently, 0.02 mol of trimethyl phosphate and 0.02 mol of antimony trioxide were added and the mixture was heated under reduced pressure (0.2 mmH).
g) After polycondensation reaction at 270°C to prepare a high degree of polymerization polyester having an intrinsic viscosity (phenol:tetrachloroethane-1:1) of 0.65 to 0.67, bis-β-hydroxyethyl terephthalate (hereinafter referred to as BHET) was prepared. ), trimethylolpropane (hereinafter abbreviated as TP), and pentaerythritol (hereinafter abbreviated as PE) in the amounts shown in Table 1, and the depolymerization reaction was carried out under a nitrogen pressure of 0.5 kg/cm2. to prepare the polyester resins shown in the table.

No. Trimellitic anhydride (hereinafter abbreviated as TMAD) was added to each of the polyesters Nos. 1, 2, and 3 in the amount shown in Table 3, and kneaded at 160°C for 60 minutes to obtain an acid value and a hydroxyl value shown in Table 3. Modified into polyester resin.

Each polyester resin in Table 3 was mixed with the formulation shown below, kneaded for 5 minutes at 100°C using three rolls to prepare a polyester resin composition, and after pulverizing and pulverizing,
．． Painted on a zinc phosphate treated steel plate of 8 x 100 x 200 (unit: m/m) and No. 1 and no. The polyester resin composition No. 2 was heated at 190° C. for 30 minutes. 3 and N
o. The polyester resin composition No. 4 was baked at 180° C. for 30 minutes to obtain the results shown in Table 4.

Also, No. 1~No. Fine powders of each of the polyester resin compositions No. 4 were stored at 40° C. for 7 days, but no blocking occurred.

Example 2 Dehydration type polyester resin Alftaratpan 11 (
(manufactured by Hoechst, trade name) was made into a paint in the same manner as in Example 1, but with the following formulation, then crushed, painted, and heated to 220°C for 30 minutes.
After baking for 0 minutes, the coating performance was evaluated in the same manner as in Example 1, and the results were 60° specular reflectance of 98, Erichsen 8 m/m, and impact resistance of 30 cr.

Reference Example 1 Same as Examples 1 and 2, but instead of YF-3860 silicone oil, Modaflow (trade name manufactured by Monsando Co., Ltd.), which is commonly used as a powder coating adjuster, was used to form a coating, crush it, and paint it. , and the results shown in Table 5 were obtained.

Example 2 No. of Example 1 In the same manner as the polyester resin composition in No. 1, except that 0.1 or 10 parts by weight of YF-3860 silicone oil was used in place of 1.2 parts by weight to make it into a paint, crush it,
After painting and baking, the results shown in Table 6 were obtained.

A polyester resin composition using 10 parts by weight of YF-3860 silicone oil was blocked during storage at 40°C.

As is clear from a comparison of Examples and Reference Examples, the polyester resin composition for powder coatings of the present invention has a high gloss finish with a high 60° specular reflectance and a finish comparable to that of solvent-based coatings. It can provide a painted surface.

In addition, when the amount of the condensate added is as small as 0.2 parts by weight or less per 100 parts by weight of the polyester resin or resin composition, almost no effect of improving the heat-fu mouth consistency is observed;
If the amount is more than 1 part by weight, problems arise in terms of stability and handling workability during storage or transportation as a powder coating due to blocking properties.

Claims (1)

[Claims] 1 Polyester resin with a softening point of 50 to 150°C or/
and resin composition 10 mainly composed of the polyester resin
0 parts by weight and polyoxyalkylene (carbon number: 2 to 8)
By mixing 0.2 to 5 parts by weight of a metal condensate of monoalkyl or alkenyl (carbon number: 1 to 24) ether (average degree of polymerization: 1 to 150) and polyalkyl (carbon number: 1 to 20) siloxane. The obtained polyester resin composition for powder coating.