JPH0258559A - Polyester resin composition and paint produced thereof - Google Patents

Abstract

PURPOSE:To provide a polyester resin composition containing a polyester resin produced by the reaction of cyclohexane-dicarboxylic acid and a diol, having excellent hardness, processability, stain resistance and weather resistance and useful as a paint, etc. CONSTITUTION:The objective composition contains a polyester resin having a number-average molecular weight of >=5,000 and produced by the reaction of an acid component containing cyclohexanedicarboxylic acid and an alcohol compound composed mainly of a diol. The amount of the cyclohexanedicarboxylic acid is 20-80mol% based on the total dicarboxylic acid component. The alcohol component and/or the acid component contain <=5wt.% of >=3-valent polyhydric alcohol and/or polybasic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester resin composition used for paints etc. that has excellent hardness, workability, stain resistance and weather resistance, and paints using the same. .

[Conventional technology]

Traditionally, painting of home appliances, etc. was done after processing and forming steel plates.
Previously done in a box-shaped form, in order to solve various problems such as streamlining the painting line, improving productivity, preventing pollution, and improving the work environment, a pre-coat painting method was developed in which flat steel plates are processed and formed after being painted. is moving to. The precoated m-plate used in this method is processed into a complicated shape after painting, so high workability is required. On the other hand, among home appliances, refrigerators, washing machines, and the like require high performance in terms of coating film hardness, stain resistance, and chemical resistance.

Conventionally, thermosetting acrylic resins have been mainly used for coating these home appliances. This is because acrylic resin paints have excellent coating hardness and stain resistance.

However, acrylic resin paints do not have enough workability to be used for pre-coating, and in order to satisfy the processability, it is necessary to soften the composition of the acrylic resin, and it is necessary to soften the composition of the acrylic resin to create a coating film that can withstand practical use. Hardness and stain resistance are difficult to demonstrate.

In addition, thermosetting polyester resins have been used for coil coatings such as colored galvanized iron, but they still have the drawback of not being able to balance processability, coating hardness, and stain resistance. However, high molecular weight polyester resins obtained by polycondensing polyester resins under reduced pressure have better processability than ordinary polyester resins, and can be used in refrigerators,
It has also been put into practical use for painting home appliances such as washing machines.

[Problem to be solved by the invention]

However, even these high molecular weight polyester resins do not have sufficient weather resistance compared to conventionally used acrylic resins.

The present invention provides a polyester resin composition that has excellent hardness, processability, stain resistance, and weather resistance, and a paint using the same.

[Means to solve the problem]

The present invention solves the above problems by using alicyclic cyclohexanedicarboxylic acid with good weather resistance as the acid component of the polyester resin.

That is, the present invention relates to a polyester resin composition containing a polyester resin having a number average molecular weight of 5,000 or more obtained by reacting an acid component containing cyclohexanedicarboxylic acid with an alcohol component containing a diol as a main component, and a polyester resin composition comprising the same. The present invention relates to a paint containing the following.

The anhydride or lower alkyl ester of cyclohexanedicarboxylic acid used as an essential component in the present invention may be used. These are preferably used in an amount of 20 to 80 mol % based on the total dicarboxylic acid components. This amount is 20
If it is less than 80 mol%, the weather resistance effect will be poor, and if it is less than 80 mol%
If it exceeds this, stain resistance tends to decrease. Note that, for the same reason, it is preferable that cyclohexanedicarboxylic acid is contained in an amount of 20 to 80 mol% of the total dicarboxylic acid residues in the polyester resin as a residue of the dicarboxylic acid component in the resulting polyester resin.

Other dicarboxylic acids used in the present invention include terephthalic acid, isophthalic acid, and aromatic dicarboxylic acids.
Examples include phthalic acid, naphthalene dicarboxylic acid, and their lower alkyl esters and acid anhydrides. Examples of aliphatic dicarboxylic acids include adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, and hemic acid. , their lower alkyl esters, acid anhydrides, etc., and one or more of these can be used.

Diols used in the present invention include ethylene glycol, l,2-propanediol, 1°3-propanediol, ■,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,5-bentanediol. , 1,6-hexanediol, 3-methylbentanediol, diethylene glycol, 1,4-cyclohexane dimetatool, 1,4-dicyclohexane dimetatool, xylylene glycol, aromatic bisphenol A ethylene oxide, propylene oxide There are adducts and the like, and one or more of these can be used.

In the present invention, a trivalent or higher polyhydric alcohol and/or a polybasic acid can be further used in an amount of preferably 5% by weight or less based on the polyester resin. When these are contained, solvent resistance and gloss are further improved.

Of course, these also include those containing both a hydroxyl group and a carboxyl group. Examples of these are glycerin, trimethylolethane, trimethylolpropane,
Pentaerythritol, dimethylolpropionic acid, trimellitic acid, pyromellitic acid, trimesic acid, etc.
One or more types of these can be used.

If the amount of these components exceeds 5% by weight, processability tends to decrease.

The polyester resin of the present invention can be produced by conventional methods. For example, 1. acid component and alcohol component,
The carboxyl groups of the acid component and the hydroxyl groups of the alcohol component are mixed in a ratio from approximately equivalent to an excess of hydroxyl groups, and if necessary, esterification or transesterification is carried out at 150 to 300 ° C under the presence of a catalyst, Then preferably 1
Excess alcohol components are removed by transesterification under reduced pressure of 1IIIllHg or less to obtain a high molecular weight polyester resin. The polyhydric alcohol and/or the polybasic acid having a valence of 3 or more may be added and reacted under normal pressure before or after the above-mentioned pressure reduction.

The polyester resin thus obtained needs to have a number average molecular weight of 5,000 or more, preferably 30,000 or less. If it is less than 5,000, workability decreases. Furthermore, if the number average molecular weight is too large, the gloss tends to decrease.

In the present invention, the "number average molecular weight" is measured using gel permeation chromatography using a standard polystyrene calibration curve.

The polyester resin composition of the present invention may contain other polyester resins in addition to the above-mentioned polyester resins to the extent that their properties are not impaired. The obtained polyester resin composition is diluted with a solvent such as an aromatic hydrocarbon, an aliphatic hydrocarbon, an ester, or a ketone, if necessary, and used as a paint, an adhesive, or the like.

The polyester resin composition of the present invention includes melamine, urea,
Amino resins such as amine resins obtained by reacting amino compounds such as benzoguanamine with formaldehyde, and etherified amine resins obtained by etherifying the amino resins with lower alcohols such as methanol, ethanol, propatool, butanol, etc. They can be combined to form a thermosetting paint. In this case, the solid content ratio (weight ratio) of the polyester resin composition and the amino resin is 90.
/10~60/40, preferably 85/'15~7
It is appropriate to mix them in a ratio of 0/30.

Furthermore, the polyester resin composition ζ of the present invention can also be made into a paint by using polyisocyanate as a curing agent. Examples of polyisocyanates include isophorone diisocyanate, diphenylmethane diisocyanate,
Examples include m-xylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, decamethylene diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, dodecane dicarbonyl diisocyanate, and the like. In addition, these can be used as pro-chlorinated agents, such as alcohols such as methanol, ethanol, and 2-butoxyshetanol, phenols such as phenol and cresol, lactams such as caprolactam and butyrolactam, and oximes such as cyclohexane oxime and methyl ethyl ketone oxime. Blocked isocyanates masked with can also be used. The amount is usually such that the isocyanate value and the hydroxyl value of the polyester resin composition are approximately 1:1.

Furthermore, if necessary, a pigment, a plasticizer, a colorant, and/or an acid catalyst such as P-toluenesulfonic acid may be appropriately added to form a paint.

The paint thus obtained can be applied to the surface of iron, non-ferrous metals, etc. by a known method such as spray coating or roll coating.

〔Example〕

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

Example 1 (1) 68.8 parts by weight of cyclohexanedicarboxylic acid (0
, 4 mol), teL/7)) 41.5 parts by weight of acid (
0.25 mol), 41.5 parts by weight of isophthalic acid (0.2
5 mol), azelaic acid 18.8 parts by weight (0.1 mol)
, 62.4 parts by weight (0.6 mol) of neopentyl glycol, 37.2 parts by weight (0.6 mol) of ethylene glycol and 0.05 parts by weight of dibutyltin dioxide at 250 °C in the presence of an inert gas. The acid value was 5.
A low molecular weight polyester resin A was obtained.

(2) Low molecular weight polyester resin A at 0.8 lnmH
A polycondensation reaction was carried out at 270° C. to obtain a polyester resin having the composition shown in Table 1 and having a number average molecular weight of 17,000.

In addition, the composition of the resin in the examples was analyzed by NMR, and the number average molecular weight was determined using a Hitachi 635 high performance liquid chromatography column with gel back (GELP).
AC) R440, R450, and R400M (all manufactured by Hitachi Chemical ■, trade names) were connected in series, a chromatogram was obtained using tetrahydrofuran as an eluent, and the calculations were made based on standard polystyrene.

Example 2 300 parts by weight of the low molecular weight polyester resin A of Example 1 was subjected to polycondensation at 0.8 mmHg and 270°C, and then
Add 7.5 parts by weight of dimethylolpropionic acid and add 250 parts by weight.
Depolymerized at °C. Acid value 5.9 of the composition shown in Table 1,
A polyester resin having a number average molecular weight of 10,500 was obtained.

Example 3 103.2 parts by weight of cyclohexanedicarboxylic acid (0.6 parts by weight)
mol), terephthalic acid 24.9 parts by weight (0.15 mol)
, 33.2 ffili parts (0.2 mol) of isophthalic acid,
9.4 parts by weight (0.05 mol) of azelaic acid, 62.4 parts by weight (0.6 mol) of neopentyl glycol, 37.2 parts by weight (0.6 mol) of ethylene glycol, and 0.05 parts by weight of dibutyltin dioxide. 2 parts in the presence of an inert gas
Esterification reaction at 50°C followed by 0.8 mdg
A polycondensation reaction was carried out at 280°C to obtain a polyester resin having the composition shown in Table 1 and having a number average molecular weight of 16,500.

Example 4 154.8 parts by weight of cyclohexanedicarboxylic acid (0.9 parts by weight)
mol), 8.3 parts by weight (0.05 mol) of isophthalic acid,
8.3 parts by weight (0.05 mol) of terephthalic acid, 62.4 parts by weight (0.6 mol) of neopentyl glycol, 37.2 parts by weight (0.6 mol) of ethylene glycol, and 0.05 part by weight of diptyltin dioxide. 25 in the presence of an inert gas
Esterification reaction at 0°C followed by 0.8 rats
A polycondensation reaction was carried out under Hg at 280°C to obtain a polyester resin having the composition shown in Table 1 and having a number average molecular weight of 16,500.

Comparative Example 1 66.4 parts by weight (0.4 mol) of isophthalic acid, 66.4 parts by weight (0.4 mol) of terephthalic acid, 37 parts by weight of azelaic acid
．． 6 parts by weight (0.2 mol), neopentyl glycol 6
2.4 parts by weight (0.6 mol), ethylene glycol 37
．． 2 parts by weight (0.6 mol) and 0 dibutyltin dioxide
．． 05 parts by weight was subjected to an esterification reaction at 250'C in the presence of an inert gas, followed by 0.8 mmHg and 280°C.
A polycondensation reaction is carried out to obtain the number average molecule 1 of the composition shown in Table 1.
Evaluation of polyester resin 16500 for production of paint The resins obtained in each example and comparative example were
50 (Shell Kagaku Co., Ltd., trade name)/cyclohexanone/cellosolve acetate=1/1/1 (weight ratio) to adjust the heating residue to 40% liquid.

The above resin solution was made into a paint using the following formulation.

Resin solution of Example or Comparative Example 300 parts by weight Melan 5
23 (Methylated melamine, Hitachi Chemical ■Product name) 30 parts by weight Rutile type titanium white 150 parts by weight p-toluenesulfonic acid 1.51 parts Thinner [Turupetz 1
50/cyclohexanone = 1/1 (weight ratio)] 69 parts by weight of the above paint was applied to a Bonderai l-4144 treated steel plate (Japan Test Panel Co., Ltd. thickness 0.5 nua) with an applicator until the dry film thickness was 2.
It was applied to a thickness of 0 μm and baked at 280°C for 80 seconds.

The properties of the resulting coating film were tested using the following test method.

The results are shown in Table 2.

Measured at a gloss incident angle of 60° (J I S K 5400
).

Pencil hardness measured using Mitsubishi Uni (JIS K 540
0).

Workability 70 x 40 m +++ test piece was cut vertically from the center by 18 mm.
It was bent at 0° and pressed.

evaluation 5...No crack.

3...1/3 crack.

1...There is a full crank.

After 24 hours, the marker ink marks on the stain resistance test piece are wiped off with a pheasant roll.

evaluation 5...No ink marks.

4...between 5 and 3.

3... Slight ink marks remain.

2...Between 3 and 1.

1... Ink marks clearly remain.

Using a weather-resistant sunshine weather meter, the gloss after 600 hours of irradiation (60° specular reflectance) was measured by 10% compared to the initial gloss.
It is shown as a percentage of 0.

Table 2 As is clear from the above results, the polyester resin composition of the present invention produces a coating film with excellent gloss, pencil hardness, workability, stain resistance, and weather resistance. Comparative Example 1 is a case in which cyclohexanedicarboxylic acid is not used, but the weather resistance is extremely poor. In Example 4, the amount of cyclohexanedicarboxylic acid is large, but the stain resistance tends to decrease.

〔Effect of the invention〕

The paint using the polyester resin composition according to the present invention is
Produces coatings with excellent gloss, hardness, workability, stain resistance, and weather resistance. Therefore, the polyester resin composition according to the present invention is particularly effective as a coating material.

Claims (1)

[Scope of Claims] 1. A polyester resin composition containing a polyester resin having a number average molecular weight of 5,000 or more obtained by reacting an acid component containing cyclohexanedicarboxylic acid with an alcohol component containing a diol as a main component. . 2. The polyester resin composition according to claim 1, wherein cyclohexanedicarboxylic acid is present in an amount of 20 to 80 mol% based on the total dicarboxylic acid components. 3. The polyester resin composition according to claim 1 or 2, which is obtained by using a trivalent or higher polyhydric alcohol and/or a polybasic acid in an amount of 5% by weight or less as the alcohol component and/or acid component. 4. A paint comprising the polyester resin composition according to claim 1, 2 or 3.