JPH0335019A - Polyester resin composition and coating compound composition using same composition - Google Patents

Abstract

PURPOSE:To obtain the title composition suitable for coating compound, etc., having excellent gloss, hardness, processing properties, contamination resistance and weather resistance containing a high molecular-weight polyester resin prepared by reacting methylpentanediol, etc., with dicarboxylic acid. CONSTITUTION:The aimed composition containing a polyester resin which is obtained by reacting (A) an alcohol component consisting essentially of 3- methylpentanediol and neopentyl glycol with (B) an acid component consisting essentially of a dicarboxylic acid (e.g. terephthalic acid or adipic acid) and has >=5,000, preferably 7,000-25,000 number-average molecular-weight.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a polyester resin composition used in paints etc. with excellent gloss, hardness, processability, stain resistance and weather resistance, and a polyester resin composition using the same. The present invention relates to coating compositions.

(Conventional technology) Conventionally, painting of home appliances, etc. was done after processing and forming the steel plate.
Previously, it was done in a box-shaped form, but in order to solve various problems such as streamlining the painting line, improving productivity, and improving the work environment for pollution prevention, a pre-coat painting method is used in which flat steel plates are processed and formed after being painted. It is being moved to The pre-painted steel plate used in this method is processed into a complicated shape after being coated, 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 hardness, stain resistance, and chemical resistance.

Conventionally, thermosetting acrylic resins have been mainly used for coating these home appliances. this is.

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 improve the composition of the acrylic resin, and to create a coating that can withstand practical use. It is difficult to demonstrate film hardness and stain resistance.

Additionally, thermosetting polyester resins have been used for coil coatings such as colored galvanized iron.

Again, there was a drawback that the balance between processability, coating film hardness, and stain resistance could not be achieved. However, high molecular weight polyester resin obtained by polycondensing polyester resin under reduced pressure has superior processability compared to ordinary polyester resin, and has been put to practical use in coating home appliances such as refrigerators and washing machines. ing.

An example of this is the one described in Japanese Unexamined Patent Publication No. 59-8770.

(Problems to be Solved by the Invention) However, these high molecular weight polyester resins do not have sufficient weather resistance compared to conventionally used acrylic resins. The method disclosed in JP-A-59-8770 has good weather resistance, but has problems in the balance between hardness and workability, as well as in stain resistance.

The present invention is characterized by hardness, workability and stain resistance.

The present invention provides a polyester resin composition with excellent weather resistance and a coating composition using the same.

(Means for Solving the Problems) The present invention provides 3-methylpentanediol, which has good flexibility, weather resistance, and hydrolysis resistance, and neopentyl glycol, which has good weather resistance and hydrolysis resistance, as alcohol components of polyester resin. The above-mentioned problem was solved by using as the main component.

That is, the present invention provides a polyester resin having a number average molecular weight of 5,000 or more obtained by reacting an alcohol component mainly composed of 3-methylpentanediol and neopentyl glycol with an acid component mainly composed of dicarboxylic acid. and a coating composition containing the same.

The 3-methylpentanediol used as an essential component in the present invention is preferably used in an amount of 20 moles or more based on the total alcohol component. When the amount is less than 20 moles, the balance between hardness and workability and stain resistance tend to deteriorate.

In addition, it is especially preferable to use less than 90 molar alcohol based on the total alcohol content, from the viewpoint of the balance between hardness and processability. Yes. Along with this, neopentyl glycol is used as an essential alcohol component. It is preferable to use 10 to 60 moles of neopentyl glycol based on the total alcohol component in view of the balance between hardness and processability and stain resistance. Other diol components include ethylene glycol,
1.2-'ropanediol, 1.3-propanediol, 1.3-butanediol, 1.4-butanediol,
There are 1.5-bentanediol, 1.6-hexanediol, diethylene glycol, 1.4-cyclohexanedimethanol, etc., and these are used in an amount of 20 moles or less based on the total alcohol component from the viewpoint of balance between hardness and processability. I'd love to see it used.

The dicarboxylic acids used as the acid component in the present invention include aromatic carboxylic acids such as terephthalic acid, inphthalic acid, heptalacid, naphthalene dicarboxylic acid, and their lower alkyl esters and acid anhydrides; As a dicarboxylic acid.

Adipic acid, azelaic acid, sepacic acid, conolilic acid,
fumaric acid, maleic acid, cyclohexanedicarboxylic acid,
Examples include hymic acid, lower alkyl esters, acid anhydrides, etc. of these, and one or more of these can be used.

In the present invention, a polyhydric alcohol having a valence of 3 or more and/or
Alternatively, the polybasic acid can be used in an amount of preferably 5% by weight or less, particularly preferably 3% by weight or less, based on the polyester resin. When these are contained, solvent resistance is further improved.

Here, if these exceed 5 degrees of friction, workability tends to decrease. Of course, these include those containing both a hydroxyl group and a carboxyl group in one molecule. Examples of these include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, dimethylolpropionic acid, trimellitic acid, pyromellitic acid, trimesic acid, etc., and one or more of these can be used.

In the present invention, the polyester resin can be produced by blending nine or more acid components and an alcohol component by a conventional method. For example, an acid component and an alcohol component are mixed in a ratio such that the carboxyl group of the acid component and the hydroxyl group of the alcohol component range from approximately equivalent to an excess of hydroxyl groups, and if necessary, the ester is heated at 150 to 300°C in the presence of a catalyst. A polyester resin having a high molecular weight can be obtained by carrying out a transesterification or transesterification reaction, and then removing an excess alcohol component by a transesterification reaction preferably under a reduced pressure of 1 mmHg or less. Trivalent or higher polyhydric alcohols and/or polybasic acids are used before or after the above-mentioned pressure reduction.

It may be added and reacted under normal pressure.

Polyester wmFi thus obtained.

It is necessary that the number average molecular weight is 5 ooo or more,
Preferably 30000 or less, particularly preferably H7000~
The range is 25,000. If the number average molecular weight is less than 5000, processability will decrease, and if the number average molecular weight is too large,
Gloss tends to decrease.

9. What is "number average molecular weight" in the context of the present invention?

It was measured using gel permeation chromatography using a standard polystyrene calibration curve.

In addition to the polyester resin described above, the polyester resin composition of the present invention may contain other known polyester resins to the extent that the properties thereof are not impaired.

The resulting polyester resin composition may contain aromatic hydrocarbons, aliphatic hydrocarbons, and esters as necessary.

It is diluted with a solvent such as ketones and used for paints, adhesives, etc.

The polyester resin composition of the present invention is melamine.

An amino resin obtained by reacting an amino compound such as urea or benzoguanamine with formaldehyde.

A thermosetting coating composition can be prepared by combining the amino resin with an amino resin such as an etherified amino resin obtained by etherifying the amino resin with a lower alcohol such as methanol, ethanol, propanol, or butanol. In this case, the solid content ratio (weight ratio) of the polyester resin composition and the amino resin is 90/10 to 60/40. Preferably, the ratio is 85/15 to 70/300.

Furthermore, the polyester resin composition of the present invention can be made into a thermosetting coating composition by using polyinsyanate as a curing agent. As polyisocyanate,
Inphorone diisocyanate, diphenylmethane diisocyanate, m-xylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate.

Examples include decamethylene diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, dodecane dicarbonyl diisocyanate, and the like.

In addition, these can be blocked with a blocking agent 1 such as methanol.

Blocked isocyanates masked with alcohols such as ethanol and 2-butoxyshetanol, 7-enols such as phenol and cresol, lactams such as caprolactam and butyrolactam, and oximes such as cyclohexane oxime and methyl ethyl ketone oxime may also be used. can.

The blending amount is usually such that the winsyanate value and the hydroxyl value of the polyester resin composition are approximately 1:1.

Furthermore, if necessary, pigments, plasticizers, colorants, and/or acid catalysts such as p-)luenesulfonic acid and dodecylbenzenesulfonic acid can be appropriately added to form the coating composition of the present invention.

The coating composition thus obtained can be applied to the surface of iron, nonferrous 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) 377.61 parts by weight (3.2 mol) of 3-71 methylbentanediol, 7281 parts by weight (7.0 mol) of neopentyl glycol, 93 parts by weight of ethylene glycol (1,
5 mol), adipic acid 146 parts by weight (1.0 mol), terephthalic acid 747iHIS (4.5 mol).

747 parts of isophthalic acid (4.5 moles) and 0.5 parts of diptyltin dioxide were charged and esterified at 250°C in the presence of an inert gas, resulting in an acid value of 5 or less.
The temperature was raised to 0℃, and the pressure was increased to 106.7 Pa (0.8 mmH
The polycondensation reaction (g) was carried out under reduced pressure to obtain a polyester resin having the composition and resin properties shown in Table 1.

Among them, the resin composition in Examples was determined by NMR.

The number average molecular weight was determined using a Hitachi 635 high performance liquid chromatography analyzer (manufactured by Hitachi, Ltd.).

Gelpack R440, R450 and R40 as columns
0M+all manufactured by Hitachi Chemical Co., Ltd. (product name)) were connected in series, a chromatogram was obtained using tetrahydrofuran as an eluent, and the calculation was made based on standard polystyrene.

Example 2.3 and Comparative Examples 1 to 3 9 was prepared in the same manner as in Example 1 except that the ingredients were changed.
A polyester resin having the resin composition and resin properties shown in Table 1 was obtained. In Example 3 and Comparative Example 2, the trivalent component was initially subjected to an esterification reaction without being charged at 280°C.
After reacting at 106.7 Pa (0.8 mmHg) for 2 hours, a trivalent component was added, kept warm for 30 minutes, and then cooled to obtain a polyester resin.

Manufacture and evaluation of coating composition The polyester resins obtained in each example and comparative example were each mixed with Solpetsuso 150 (manufactured by Etsuso Standard Oil, brand name of organic solvent)/cyclohexanone/cellosolve acetate = 1/1/1 (by weight). The heating residue was adjusted to a solution of 40% by weight ratio). This polyester resin solution was made into a paint using the following formulation.

Rutile type titanium white 150 parts by weight p-) Luenesulfonic acid 15 Weight 11 The obtained coating composition was applied to a Bonderite◆144 treated weir steel plate (Japan Test Panel Co., Ltd. thickness 0.5 wm) with an applicator to a dry film thickness of 20 μm. It was applied and baked at 280°C for 65 seconds.

The properties of the resulting coating film were tested according to the test method below. The results are shown in Table 2.

Test method Gloss Measured at an incident angle of 60'' according to JIS K 5400.

Pencil hardness was measured according to JIS K 5400 using a Mitsubishi Uni Pencil (manufactured by Mitsubishi Pencil ■).

Workability: A coated test piece measuring 70 x 40 fm was bent 1800 degrees from the center in the longitudinal direction and pressed.

Evaluation 5: No cracks 3: Cracks occurred in 1/3 1: Cracks appeared on the entire surface After 24 hours, the black and red marker ink marks on the stain resistance test piece were wiped off with ethanol and visually judged. .

Rating 5... No ink marks at all 4... In between 5 and 3 3... Slight ink marks remaining 2... In between 3 and 1 1... Weather resistant Sunshine Uezao with clear ink marks left The gloss (600 specular reflectance) after 800 hours of irradiation was measured using a meter and expressed as a percentage of the initial gloss.

As seen in Examples 1 to 3, when the polyester resin composition of the present invention is used, a coating film having excellent gloss, hardness, workability, stain resistance, and weather resistance can be obtained.

Comparative Example 1 is a follow-up test of the polyester resin disclosed in JP-A-59-8770.

Processability and stain resistance are reduced. Comparative Example 2 is a case where the molecular weight is small, but processability and stain resistance are reduced. Comparative Example 3 This is an example in which ethylene glycol was used instead of ti3-methylpentanediol, but the weather resistance deteriorated.

(Effect of the invention) The polyester resin composition according to the present invention has gloss.

It can provide a coating film with excellent hardness, processability, stain resistance, and weather resistance, and is effective as a coating composition at a rate of 9%.

Claims (1)

[Scope of Claims] A number average molecular weight of 5,000 or more obtained by reacting an alcohol component mainly composed of 1,3-methylpentanediol and neopentyl glycol with an acid component mainly composed of dicarboxylic acid. A polyester resin composition comprising a polyester resin. 2. The polyester resin composition according to claim 1, wherein 2,3-methylpentanediol is contained in an amount of 20 mol% or more based on the total alcohol component. 3. As the alcohol component and/or acid component, 5% by weight or less of polyhydric alcohol and/or polybasic acid of 3 or more valences (
Claim 1 or 2 obtained by using the amount of (excluding 0)
The polyester resin composition described. 4. A coating composition comprising the polyester resin composition according to claim 1, 2 or 3. 5. The coating composition according to claim 4, further comprising an amino resin or a polyisocyanate as a curing agent component.