KR950006717B1 - Polyester copolymer resin - Google Patents

Abstract

Polyester resin of mean molecular weight 2,000-8,000 for preventing damage of painted film from ultraviolet radiating is copolymerized with 10-40 mol% acid components including aliphatic carboxylic acid, aromatic carboxylic acid, saturated alicyclic carboxylic acid as 1,4-cyclohexane dicarboxylate or its ester derivative and 1-10 mol% polyvalent alcohol component such as trimethylol propane, ethylene glycol, propylene glycol, neopentyl glycol and p-xylene glycol, catalysts such as superoxides of Ca, Ce, Pb, Mn, Zn, Mg, Sb, etc., and germanium oxide, a thermal stabilizer with phosphorylated compounds. The polyester resin has good properties of tortuosity, hardness and weathering resistance.

Description

Copolymer polyester resin for coating

The present invention relates to a co-polyester resin useful as a binder resin for paints, and in particular, by renewing the composition of the synthetic powder in detail, paints, coatings, adhesives, etc., which must be prevented from damaging the coating film by ultraviolet rays, especially when exposed to the outside. The present invention relates to a copolyester resin for paints, which is suitable as a binder resin for upper paints and has excellent bendability, pencil hardness and high weather resistance.

Among general coil coating products, oil-based alkyd resins have been conventionally used as binders for the top coating of building exterior materials or for the top coating of automobiles.

In order to improve such a disadvantage, Japanese Patent Application Publication No. 62-153354 proposes a method of adding a UV stabilizer in the manufacture of a binder, but in this case, when the high temperature drying method such as coil coating is performed, the UV stabilizer is thermally decomposed and the film is orange peeled. Another problem arises, such as a phenomenon that changes.

In addition, US Pat. No. 4,524,165 or 4,525,504 discloses a method for producing a plastic molded article using 1,4-cyclohexanedicarboxylic acid or its ester derivative thereof as a raw material of a polyester copolymer and adding an ultraviolet stabilizer thereto. Started.

However, in this method, when the copolymer is made of a copolymer having a high molecular weight, such a co-molecular weight resin has a crystal in which the workability of the paint and the solvent resistance of the coating film are poor when used as a binder of the solvent type paint.

In addition, polyester copolymer resins containing only phthalic anhydride or aromatic carboxylic acid as the main acid component have been widely used. This has a problem of being difficult to obtain flexibility and excellent weather resistance while having excellent gloss and curability. Polyester copolymer resin containing only an acid as a main acid component has excellent flexibility but poor pencil hardness and weather resistance.

Accordingly, an object of the present invention is to provide a copolyester polyester resin having a new composition exhibiting high weather resistance while having good flexibility and pencil hardness when coated with a copolyester polyester resin.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a copolymerized polyester resin in which 1,4-cyclohexanedicarboxylic acid or an ester derivative thereof is contained as an acid component and an acid component and a polyhydric alcohol component are copolymerized, wherein 10 to 40 mol% of the acid component is It is comprised from 1, 4- cyclohexanedicarboxylic acid or its ester derivative, At the same time, 1-10 mol% of the said polyhydric-alcohol component is a copolymer comprised from trimethylol propane, It is characterized by the above-mentioned.

Referring to the present invention in more detail as follows.

In the present invention, 1,4-cyclohexanedicarboxylic acid trimethylolpropane is used as a raw material for producing a copolymerized polyester resin exhibiting high weather resistance while having both good flexibility and pencil hardness when the copolymerized polyester resin is coated. It introduces and manufactures a copolyester by a well-known method.

As the acid component used in the present invention, aliphatic carboxylic acid, aromatic carboxylic acid, saturated alicyclic carboxylic acid or anhydride is added. For the purpose of balancing the high weatherability, flexibility and hardness of the present invention, 10 to 40 mol% of the acid component is It should consist of 1,4-cyclohexane dicarboxylic acid or its ester derivatives.

In general, saturated alicyclic has the advantage of less ultraviolet absorption than aromatic and superior hardness to aliphatic. Among saturated alicyclics, 1,4-cyclohexanedicarboxylic acid has less steric hindrance than cyclohexane anhydride. It is also excellent in reactivity with the polyhydric alcohol at the 4 position, and excellent in reactivity during copolymerization. However, if 1,4-cyclohexanedicarboxylic acid or its ester derivative is 10 mol% or less in the acid component, the weather resistance is not improved. If it is 40 mol% or more, the pencil hardness and the chemical resistance become weak.

In addition, in the present invention, a trihydric alcohol was introduced in the alcohol component, which is intended to enhance the reactivity with the reaction product melamine resin, and has a hydroxyl group that reacts with the amino resin in the main chain as well as the side chain of the copolymer polyester during high temperature drying. Since the gel density is increased by thermal curing of, it shows an excellent effect on chemical resistance and weather resistance. However, when an excess of trihydric alcohol is used in an alcohol content of more than 1 mol%, the reactivity of the resin and the flexibility of the coating film are poor, thereby making it impossible to achieve the present invention.

The acid components which can be used in the present invention include phthalic anhydride, maleic anhydride, tetrachloride anhydride, trimaleic anhydride and liver are anhydrides and terephthalic acid, isophthalic acid, isophthalic acid isophthalic acid and its ester derivatives. Uses something like

ROOC-(CH ₂ ) _-n COOR

Wherein n is an integer from 4 to 10 and R is -H or -CH ₃ .

Meanwhile, in the present invention, only 1,4-cyclohexanedicarboxylic acid and its ester derivative are used as the alicyclic acid component, and as the polyhydric alcohol component in the polyester copolymer, ethylene glycol, propylene glycol, neopentyl glycol, butanediol and trimethylol Propane, diethyleneglycol, 1,4-cyclohexanedimethylol, polyethylene glycol, p-xylene glycol and the like are used.

In addition, as the esterification catalyst, superoxides of Ca, Ce, Pb, Mn, Zn, Mg, and Sb, and Sb ₂ O ₂ , GeO _2, and the like are used. do.

In the present invention, the number average molecular weight of the prepared copolymerized polyester resin is 2,000 to 8,000. If the number average molecular weight of the prepared copolymer is 2,000 or less, the hardness is lowered and the chemical resistance is weakened. This is weakened.

In addition, as the amino formaldehyde resin used as a heat curing agent for the paint of the present invention may be used a melamine resin or urea resin etherified with a monohydric alcohol having 1 to 4 carbon atoms, but melamine resin is preferred in terms of weather resistance.

Using such a component to prepare a copolymerized polyester resin by a known method, but a copolymerized polyester resin having a number average molecular weight of 2,000 ~ 8,000 was produced, according to the present invention, the copolymer resin is different from the conventional composition of the coil It is very useful as a binder for coating or automotive top coating or film coating, and especially it can be used as a binder resin having excellent weather resistance and excellent bending property and pencil hardness.

Hereinafter, the present invention will be described in detail based on examples.

[Examples 1-5]

A three-necked flask, thermometer, cooler, mantle, stirrer, and vacuum pump were prepared.

Put acid and alcohol into 500 ml three-necked flask according to Table 1, add Zn superoxide as esterification catalyst, and gradually raise the temperature from room temperature to 230 ℃. And a thermal stabilizer were added to carry out the light reaction, and the temperature was raised to 280 ° C. to react so that the number average molecular weight was in the range of 2,000 to 8,000. The ingredients, the ratio of components and the number average molecular weight of the prepared copolymer are shown in Table 1 below.

[Comparative Examples 1 ~ 5]

The reaction process was carried out in the same manner as in Example 1, using the ingredients and the ratio of the ingredients according to the following Table 1 and the results are shown in Table 1.

Experimental Example

In order to evaluate the performance of the present invention, the polyester copolymer synthesized as described above was made into a 60% solution using Solvesso # 150 / # 200 = 8/2 solvent to prepare a dispersion blended phase, followed by dissolution mixing. Made paint.

(Distributed formulation)

TiO ₂ (rutile) 60 g

60% resin solution 26g

Solvesso # 150 15g

Wetting Agent (eg Modaflow) ⁽¹⁾ 0.05g

(Dissolution compounding)

Dispersion Formulation 100.05 g

60% resin solution 42.0 g

Cyme1303 ⁽²⁾ 15.0 g

n-butanol 4.0g

1.3 g of toluenesulfonic acid 10% solution

* Note: (1) Monsanto, USA

(2) Cyanamid, USA

Coating properties of the paints prepared as described above using the resins according to the Examples and Comparative Examples are shown in Table 1 below.

TABLE 1

Resin Synthesis Conditions and Paint Coating Properties

(1) GPC method: Milton Roy Co., Ltd. was used and the standard was determined by polystyrene having a molecular weight of 3600, 7000, and 9200, and the resin was dissolved in tetrahydrofuran and measured.

(2) After coating the paint on the glass plate and drying it with a hot air dryer at 180 ° C for 20 minutes, the reflectance of the light source at 60 ° reflectance with respect to the incident light source was measured using BY-Gardner's micro-TRI gloss.

(3) A coating material was coated on a 0.3 mm thick copper plate, dried at 270 ° C. for 1 minute with a hot air dryer, and the coating film hardness was measured with a Mitsubishi pencil.

(4) The copper plate which measured pencil hardness as mentioned above was bent at 180 degrees, and the severe damage of the coating film of the curved surface was 0 points, and the good one was 5 points.

(5) Measures how much 60 ° gloss is maintained to the initial value after 500 hours irradiation with QUV.

Claims (2)

1,4-cyclohexanedicarboxylic acid or an ester derivative thereof is contained as an acid component, and the acid component and the polyhydric alcohol component are copolymerized polyester resins in which 10 to 40 mol% of the acid components is 1,4-cyclo A co-polyester resin comprising a hexanedicarboxylic acid or an ester derivative thereof, while at the same time 1 to 10 mol% of the polyhydric alcohol component is a copolymer composed of trimethylol propane. The copolymerized polyester resin according to claim 1, wherein the copolymer has a number average molecular weight of 2,000 to 8,000.