JPS61243863A - Water-based polyester resin paint composition - Google Patents

Abstract

PURPOSE:To obtain paint which has improved storage stability and gives a coating film having improved smoothness, gloss and resistance to water, weather and chemicals, by using 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic acid as an acid component. CONSTITUTION:A water-based polyester resin paint compsn. is obtd. by using 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic acid or its anhydride as an acid component. The wateriness of the paint compsn. can be improved by further neutralizing the remaining carboxyl groups. The polyesters can be classified into various types from the viewpoint of structure and are synthesized by several steps according to the desired structures, and their physical properties can be modified by properly choosing reaction conditions and the type of alcohols to be used. Ammonia is preferred as the neutralizing agent for neutralizing the carboxyl groups to impart wateriness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an aqueous polyester resin coating composition.

[Prior Art] Alkyd resin, which is a type of polyester, is widely used as the most common paint raw material.

However, since the conventional air oxidation polymerization type oil-modified alkyd resin paint is a kind of solvent-based paint, it is essential to use a diluent such as xylene or mineral turpentine to adjust the viscosity from the viewpoint of workability. In addition, flaxseed oil is used as a raw fatty acid,
Unsaturated fatty acids such as soybean oil and safflower oil are used, but these fatty acids develop a yellow-brown color during the air oxidation polymerization process and are therefore not preferred for light-colored paints.

Since water-based alkyd resin paints hardly use organic solvents such as xylene or mineral turpentine, it is possible to prevent or reduce the risk of fire and air pollution caused by organic solvents. On the other hand, water-based alkyd resin paints use a large amount of emulsifier to make them water-based, and water-soluble polyethylene glycol, etc. may be introduced as a component of the alkyd resin, resulting in a coating film with considerably poor water resistance. It has become.

In addition, water-based alkyd resin paints generally repel or dent due to oil-based dust and dirt, and in the case of amino alkyd paints, the crosslinking agent aminoplast and water-based alkyd resin react during storage, causing It tends to be unstable.

[Problems to be Solved by the Invention] In view of the fact that water-based paints are useful from the aspects of safety and hygiene and resource saving, the present inventors have solved the following problems: ■ Water resistance and weather resistance of the paint film. properties, chemical resistance, ■paint film smoothness and gloss,
We conducted extensive research to improve the physical properties of the paint film, such as flexibility, impact resistance, and hardness, and the storage stability of the paint.

On the other hand, 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride (hereinafter referred to as TD
It is called A. Formula (1) is a promising compound that can be synthesized relatively easily by the [)iels-Alder reaction between styrene and maleic anhydride. Polyester resin water-based paints containing TDA as an acid component have not yet been investigated, and as part of the application development of TDA, we investigated the possibility of its application and found that the hydric acid of TDA is a tetrafunctional polybase. It is an acid, and if necessary, some of the four carboxyl groups are esterified with monohydric to tetrahydric alcohols, and some of them remain as free carboxylic acids, thereby increasing the water resistance of the paint film and making the paint water-based. By being able to freely control the balance and by changing the monohydric to tetrahydric alcohols, the problems of water-based paints, such as poor storage stability and easy coating unevenness, can be avoided. We have found that this problem can be solved, and based on this knowledge, we have completed the present invention.

That is, the present invention provides a novel aqueous polyester resin coating composition containing TDA or its anhydride as an acid component, and furthermore, a polyester resin in which carboxyl groups and, if necessary, hydroxyl groups are also allowed to remain. The object of the present invention is to provide a novel coating composition characterized in that it imparts aqueous properties by neutralizing the carboxyl groups.

Means for Solving Problem E] The polyester according to the present invention has TDA or its hydric acid as an acid component. Furthermore, the aqueous properties are improved by neutralizing the remaining carboxyl groups.

Various types of structural engineering can be considered for the polyester,
It is synthesized in several stages depending on the desired structure, and its physical properties can be freely changed by appropriately selecting reaction conditions, type of alcohol, etc.

A typical estimated structure of a TDA derivative esterified with a monovalent to tetravalent alcohol is shown in the following formula (2). However, it is not necessarily limited to this (n: 2-4, R:
Divalent to tetravalent alcohol residue, R, divalent alcohol residue, R2: hydrogen 1.

Or it represents a monovalent saturated or unsaturated alcohol residue having 1 to 18 carbon atoms. ) Here, if a dihydric alcohol such as 1,4-decanediol or neopentyl glycol is used for R, the following formula (3)
It is estimated that the structure is as follows.

(T: TDA residue, R: dihydric alcohol residue: 1 2 ° R, R, same as formula (2)) In addition, as in formula (4), compounds with lower or higher molecular weight than formula (2) Also, transesterified products are produced during the reaction. This point is determined by the following equation (5), (n: e.g. O~101
T: TDA residue, R: divalent alcohol residue, R1, R
2: Same as formula 2) If 1,10-decanediol, polypropylene glycol, etc. is used for R in formula (2),
In particular, the flexibility of the coating film is excellent. Furthermore, if a branched glycol such as neopentyl glycol is used as R5R1 in formula (2), the water resistance of the coating film and the storage stability of the paint will be further improved. In addition, if a trivalent or tetravalent alcohol is used as R, it is estimated that the structures shown in formulas (5) and (6) will be obtained, and the crosslinking density will be improved, so it is possible to further improve the coating hardness. It is possible.

R: trihydric alcohol residue such as glycerin or trimedylolpropane, T: TDA residue, R1, R2: same as formula (2)) R(X)4 (6) (However, R: pentaerythritol, Tetrahydric alcohol residue such as diglycerin, T: TDA residue, 1 2
.

R, R, same as formula (3)) In addition to the above, R can be ethylene glycol, propylene glycol, diethylene glycol, 1,6-hexanediol, cyclohexane dimethylol, diglycerin, etc., but is not limited to these. It's not something you can do. Among the polyhydric alcohols, dihydric alcohol is mainly used as R1.

R2 is hydrogen or a saturated or unsaturated monohydric alcohol having 1 to 18 carbon atoms. Specifically, methanol,
Ethanol, isopropanol, propatool, butanol, 3-methyl-3-methoxy-butanol, amyl alcohol, hexyl alcohol, octatool, isooctatool, decanol, undecanol, lauryl alcohol, tridecanol, myristyl alcohol,
Examples include saturated alcohols such as cetyl alcohol and stearyl alcohol, unsaturated alcohols such as allyl alcohol, oleyl alcohol, and rillyl alcohol, and alcohols such as cyclohexanol and benzyl alcohol. Among the above-mentioned alcohols, those having a relatively large molecular weight and a high boiling point, such as lauryl alcohol and oleyl alcohol, are preferred for production.

A water-based polyester resin is produced using TDA and a monovalent to tetravalent alcohol, but for example, the storage stability as a paint, the flexibility of the coating film, gloss, impact resistance, hardness, etc. Considering this, we mainly used (7) using oleyl alcohol, 1,10-decanediol, ethylene glycol, etc.
It is preferable to set the reaction conditions, raw material charging ratios, etc. so that the estimated structure is as shown in the formula.

(R2 is a dihydrogen or alcohol residue, and there are two or less hydrogens among the four R2s.) What should be noted during the reaction is that the acid value and hydroxyl value should be within a certain range. Since the acid value contributes to water dilution performance, it is in the range of 25 to 100, preferably 30 to 8.
It is 0.

It is desirable to set the reaction conditions so that the hydroxyl value is in the range of 20 to 1,501, preferably 25 to 100, in order to facilitate the reaction with the aminoplast described below.

During production, esterification with monovalent to tetravalent alcohols can be carried out under normal reaction conditions, and small amounts of known esterification catalysts such as sulfuric acid and p-toluenesulfonic acid may also be used. Alternatively, an entrainer such as toluene or xylene can be used to facilitate dehydration.

Ammonia, primary to tertiary amines, or organic amines such as hydroxylamine are used as neutralizing agents to neutralize carboxyl groups and impart aqueous properties. Specific organic amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine,
Triethylamine, monoethanolamine, jetanolamine, triethanolamine, N-methylethanolamine, monoisopropanolamine, diisopropanolamine, methyldiisopropanolamine, pyridine, piperazine, piperidine, etc. can be used. .

Ammonia is generally preferred. The amount used may be sufficient to neutralize some or all of the free carboxyl groups, specifically, the solid content of the aqueous polyester resin, 10
The amount of ammonia (28% aqueous solution), amine, etc. is 0.5 to 100 parts by weight relative to 0 parts by weight.

Since the monovalent to tetrahydric alcohol reactant of TDA or its neutralized product alone has a relatively low molecular weight, it may not form a sufficient film even when applied to the object to be coated.

Therefore, it is preferable to use aminoplast for crosslinking. Aminoplasts include, for example, initial condensates of melamine and formaldehyde or paraformaldehyde, methanol, ethanol, isopropanol,
Examples include those that have been alkyl etherified with alcohols such as monomethylolmelamine, dimethylolmelamine, hexamethylolmelamine, and the like that have been made water-soluble. In addition to the above-mentioned melamine resin, urea-
Formaldehyde resin, guanamine formaldehyde resin, etc. can also be used or used in combination.

The aminoplast can be appropriately selected from various aminoplasts as required, but methylolmelamine resin which has been converted into methyl ether is generally preferred. Water-soluble polymethylol acrylamide and polymethylol methacrylamide can also be used.

The amount used is 5 to 50 parts by weight, preferably 10 to 50 parts by weight of aminoplast per 100 parts by weight of the aqueous polyester solid content.
It is 30 parts by weight.

When diluting the polyester resin with water after neutralizing it, it is preferable to use a small amount of a water-soluble solvent in order to improve the gloss of the coating film, reduce its viscosity, and the like.

Specifically, monohydric alcohols such as methanol, ethanol, isopropanol, n-propanol, 3-methyl-3-methoxybutanol, butanol, 5ec-butanol, and diacetone alcohol, ethylene glycol, diethylene glycol, and propylene glycol. and their methyl, ethyl, butyl ethers, ethylene glycol, diethylene glycol, propylene glycol mono- or diacetates, mono-acetate methyl, ethyl, ethers, acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like. The amount used is water-based polyester resin solid content 10
0 to 50 parts by weight, preferably 0 to 50 parts by weight
It is 20 parts by weight.

A general-purpose additive for making water-based polyester resin paints,
That is, additives such as leveling agents, antifoaming agents, dispersants, anti-sagging agents, thickeners, and pigments such as calcium carbonate, carbon black, and titanium oxide can be used as appropriate depending on the purpose.

The water-based polyester resin, water-soluble aminoplast, and other additives are mixed using a known mixing method, such as a sand mill, a three-roll paint mixer, etc.
It can be a paint composition.

As a method for coating the composition of the present invention thus obtained, various coating methods such as dipping, dip coating, spray coating, electrostatic coating, and roll coater can be applied. The heat curing conditions after coating vary depending on the TDA esterification method, the type of aminoplast used, other additives, etc., but are usually heated and dried at 80 to 200°C for 5 to 40 minutes to form a cured coating. can do.

The water-based polyester resin in the present invention has gloss, hardness,
Because they have excellent flexibility and water resistance, metal containers,
It is suitable as a paint vehicle for metal products such as vehicles, office equipment, and metal plates.

Water-based polyester resins mainly composed of TDA are also effective as paint vehicles, but they can be made into polymers by selecting appropriate reaction conditions, and can be used as water-soluble polymers such as thickeners, binders, etc. Use as a glue, sizing agent or coating agent or protective colloid is also possible.

[Example] The present invention will be explained in detail below using Examples and Comparative Examples.

Example 1 200 parts by weight of TDA was added to a four-loaf flask equipped with a stirring device, a thermometer, a decanter and a dropping device, and the
178 parts by weight of heoleyl alcohol in 190°C molten TDA which had been heated and melted at 200°C was added dropwise over 20 minutes, and the reaction was continued at that temperature for an additional hour. The hydroxyl value after 1 hour was 0°9. After cooling to 160℃,
58 parts by weight of 1.10-decanediol was added dropwise over 20 minutes, and the reaction was continued at 160°C for an additional hour. The hydroxyl value after 1 hour was 4.3. Cool to 140°C, add 42 parts by weight of ethylene glycol, 50 parts by weight of toluene, p
- 0.2 parts by weight of toluenesulfonic acid was added and stirred at 140°C for 2 hours. During dehydration, the amount was 12 parts by weight. Thereafter, the mixture was cooled to 80° C., and a small amount of ethylene glycol that had not reacted with the toluene was distilled off under reduced pressure. The amount of toluene recovered was 50 parts by weight. The acid value was 79.

Furthermore, at the same temperature, 30 parts by weight of 28% ammonia water, 140 parts by weight of spotted vine, 130 parts by weight of ion-exchanged water, 5
20 parts by weight of ec-butanol was added to obtain 685 parts by weight of an aqueous polyester resin. Next, the mixture was cooled to 30° C., and 80 parts by weight of Sumimaru 50W (manufactured by Sumitomo Chemical, methylated melamine resin non-volatile content 78±2%) was added and stirred well.

Example 2 The same procedure as Example 1 was carried out except that 133 parts by weight of polypropylene glycol (#400) was used instead of 1.10-decanediol. The acid value was 67. Ammonia water, ion exchange water, butyl cellosolve, and 5ec-butanol were added in the same manner as in Example 1 to obtain 770 parts by weight. Sumirol 50W was also added in the same manner.

Example 3 The same procedure as Example 1 was carried out except that 34 parts by weight of neopentyl glycol was used instead of 1.10-decanediol. The acid value was 83. Aqueous ammonia and the like were added in the same manner to obtain 660 parts by weight.

Sumimaru 50W was added in the same way.

Example 4 The same procedure as Example 1 was carried out except that 29 parts by weight of trimethylolpropane was used instead of 1.10-decanediol. The acid value was 85. Aqueous ammonia and the like were added in the same manner to obtain 675 parts by weight. Sumimaru 50W was added in the same way. A paint was prepared by adding 64 parts by weight of titanium oxide, 20 parts by weight of butyl cellosolve, and ion-exchanged water to 200 parts by weight of the aqueous polyester resin containing Sumimaru 50W using a three-roll mill. Ion-exchanged water was added to this to give a viscosity of Ford Cup NQ4 (20° C.) of 75 seconds to create an aqueous polyester resin paint with a non-volatile content of 52% and a pigment weight concentration of 32%.

Example 5 200 parts by weight of TDA was added to the same four-loaf flask as in Example 1.
Add 270 parts by weight of oleyl alcohol and heat at 150°C.
The mixture was stirred for some time to react. Thereafter, 58 parts by weight of 1.10-decanediol, 0.2 parts of p-t'luenesulfonic acid
50 parts by weight of toluene were added, and the mixture was reacted at 140°C for 2 hours. The amount of water removed was 6 parts by weight. Further, 41 parts by weight of ethylene glycol was added, and the mixture was reacted at 140°C for 2 hours.

The amount of water removed was 12 parts by weight. Next, cool to 80℃,
Toluene and a small amount of unreacted ethylene glycol were distilled off under reduced pressure. The acid value was 34.

Furthermore, at the same temperature, 20 parts by weight of 28% ammonia water, 40 parts by weight of butyl cellosolve, 100 parts by weight of ion exchange water, 5e
25 parts by weight of c-butanol was added to obtain 735 parts by weight of an aqueous polyester resin. 80 parts by weight of Sumimaru 50W was added at 30°C.

Example 6 65 parts by weight of titanium oxide (rutile type) was added to 200 parts by weight of the aqueous polyester resin containing melamine resin prepared in Example 5.
20 parts by weight of butyl cellosolve and ion-exchanged water were added to prepare a paint using a three-roll mill.

Ion-exchanged water was added so that the viscosity was Ford Cup No. 4 (20°C) for 75 seconds. An aqueous polyester resin paint having a non-volatile content of 52% and a pigment weight concentration of 32.1% was prepared.

Next, a comparative example will be shown.

Comparative Example 1 Sumimaru 50W was added to 150 parts by weight of commercially available water-based alkyd resin Aloron 580 (manufactured by Kuuchaku Arrow, non-volatile content 42%).
20 parts by weight was added to adjust the solid content ratio to 20/80, and baked enamel was prepared.

Comparative Example 2 Sumimaru 50W was added to 150 parts by weight of commercially available Fluid Resin Water Sol S-124 (Dainippon Ink Chemical Co., Ltd.) to adjust the solid content ratio to 20/80, and 40 parts by weight of titanium oxide was added to adjust the pigment weight concentration. A water-based alkyd resin paint was prepared with a concentration of 33.3%.

Comparative Example 3 150 parts by weight of Aloron 580, Sumimaru 5OW20
The weight parts were thoroughly mixed, the solid content ratio was adjusted to 20/80, and 39 parts by weight of titanium oxide was added to prepare an aqueous alkyd resin paint with a pigment weight concentration of 33.3%.

Baked enamels obtained in Examples 1 to 6 and Comparative Examples 1 to 3,
The paint was applied to a cold-rolled steel plate with an applicator to a thickness of 30±3 μm, and baked at 140° C. for 20 minutes.

[Effects of the invention] As is clear from the table, the water-based polyester resin using TDA has excellent coating film water resistance, adhesion, impact resistance, smoothness, gloss, flexibility, hardness, and coating storage stability. You can see that

Claims (2)

[Claims] (1) An aqueous polyester resin coating composition comprising 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic acid or its anhydride as an acid component. (2) A polyester in which a carboxyl group of an acid component remains and, if necessary, a hydroxyl group, which is imparted with aqueous properties by neutralizing the carboxyl group. The aqueous polyester resin coating composition described in (1).