JPH08165408A - Aqueous resin composition - Google Patents

Abstract

(57) Abstract: Amino compound: 1 mol, benzoguanamine and / or melamine; formaldehyde: 1.0 to 10 mol;
Polyhydroxycarboxylic acid: 0.05 to 0.4 mol, dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolvaleric acid and / or gallic acid; Alcohol: 0.5 to 20 mol, aliphatic alcohol having 3 to 20 carbon atoms, alicyclic alcohol Alternatively, an aqueous resin composition based on an oxycarboxylated and alkyl etherified amino resin consisting of four components of an aromatic alcohol. The amino resin is obtained by simultaneously condensing a polyhydroxycarboxylic acid and an alcohol using dibutyltin oxide or monobutyltin oxide as a catalyst. [Effect] The amino resin has stable dispersibility in water for a long time,
Further, this resin composition is useful as a curing agent for paints and can form a coating film having excellent boiling water resistance and steam sterilization resistance. Furthermore, the amino resin can be produced in a one-step process, which is industrially advantageous.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous resin composition, and further to an oxycarboxylated and alkyl etherified amino resin composition, which can be used as a coating material, ink, adhesive, etc. Is.

[0002]

2. Description of the Related Art In recent years, in order to prevent air pollution caused by organic solvents emitted from paints and adhesives, conventional solvent-based paints are being changed to water-based paints. Methyl etherified melamine resins are often used in water-based paints using amino resins as curing agents from the viewpoint of water-based properties. U.S. Pat. No. 3,464,946 and U.S. Pat. No. 3,444,114 are disclosed as techniques for making the resin aqueous. However, since this curing agent is a methyl etherified melamine resin, the boiling water resistance and processability of the cured coating film are insufficient, and a satisfactory coating film could not be obtained.

By the way, as a method for improving this, Japanese Unexamined Patent Publication No. Hei.
-108849 and JP-A-6-287263 are disclosed. However, in the former method, the butyl etherified melamine resin and the butyl etherified benzoguanamine resin are made water-based, but since the glycol ether compound is an essential component, the steam sterilization resistance of the obtained coating film is poor. Further, this is a two-step process of co-condensing an oxycarboxylic acid and a glycol ether compound after producing an alkyl ether compound, which is complicated in terms of production. Furthermore, in the latter method, the oxycarboxylic acid is directly introduced into the methylolated amino resin instead of the exchange reaction with the alkyl ether, so that the operation is simplified and the free acid remaining in the amino resin is small. Become. However, in the coating film of the obtained aqueous product, the boiling water resistance is considerably improved, but the steam sterilization resistance is still insufficient.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides an aqueous oxycarboxylated and alkyl etherified amino resin composition which gives a coating film having excellent water resistance under severe conditions, ie, boiling water resistance and steam sterilization resistance. It is to provide things.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that when producing an amino resin, a specific amino compound, an oxycarboxylic acid and an alcohol, and their By selecting a specific ratio and simultaneously condensing an oxycarboxylic acid and an alcohol, an oxycarboxylated and alkyl etherified amino resin was obtained, and the fact that a composition comprising this amino resin was found to be effective was found in the present invention. I arrived.

That is, the present invention is an aqueous resin composition comprising an oxycarboxylated and alkyl etherified amino resin obtained by reacting an amino compound, formaldehyde, polyhydroxycarboxylic acid and alcohol. The above oxycarboxylated and alkyl etherified amino resin is obtained by using the following four components as raw materials and condensing polyhydroxycarboxylic acid and alcohol therein at the same time. -Amino compound: 1 mol, benzoguanamine and or melamine-Formaldehyde: 1.0 to 10 mol-Polyhydroxycarboxylic acid: 0.05 to 0.4 mol, dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolvaleric acid and / or gallic acid-Alcohol: 0.5 to 20 mol, aliphatic alcohol, alicyclic alcohol or aromatic alcohol having 3 to 20 carbon atoms

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an oxycarboxylated and alkyl etherified amino resin means an amino compound, formaldehyde, polyhydroxycarboxylic acid and an alcohol as raw materials, and an amino compound is methylolated with formaldehyde. It is obtained by dehydration condensation of methylol group and hydroxyl groups of polyhydroxycarboxylic acid and alcohol. The skeleton of the amino resin has a carboxyl group, an alkyl ether group, a methylol group and an imino group.

Examples of the amino compound used in the present invention include benzoguanamine and melamine, which may be used alone or in combination. The polyhydroxycarboxylic acid used in the present invention has two or more hydroxyl groups and one or more carboxyl groups, and examples thereof include dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolvaleric acid and gallic acid. , One or more of these can be used. Among these, dimethylolpropionic acid and dimethylolbutanoic acid are particularly preferable. When an oxycarboxylic acid having only one hydroxyl group is used instead of the above polyhydroxycarboxylic acid, the number of hydroxyl groups in the oxycarboxylic acid is small, so this oxycarboxylic acid is difficult to introduce into the amino resin, and the water of the resulting resin is Dispersibility becomes poor.

It is essential that the alcohol used in the present invention has 3 to 20 carbon atoms. For example, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert- alcohol. Aliphatic alcohols such as butyl alcohol, n-octyl alcohol or 2-ethylhexyl alcohol; alicyclic alcohols such as cyclohexanol; aromatic alcohols such as benzyl alcohol, and one or more of them can be used. . If the alcohol having 1 or 2 carbon atoms is used instead of the above alcohol, the boiling resistance of the resulting coating film is poor.

The ratio of the amino compound, formaldehyde, polyhydroxycarboxylic acid and alcohol used in the present invention is 1.0 to 10 mol of formaldehyde and 0.05 to 0.4 mol of polyhydroxycarboxylic acid per mol of the amino compound.
Mol and alcohol 0.5 to 20 mol. If the proportion of formaldehyde is less than 1.0 mol, methylolation and alkyl etherification will be insufficient, resulting in poor curability and resin solubility. On the other hand, if the proportion exceeds 10 moles, formaldehyde is substantially excessive in the reaction with the amino compound, and the amount must be removed in the subsequent step, which is economically unfavorable.

The proportion of polyhydroxycarboxylic acid is 0.05
If it is less than the molar amount, the subsequent hydration will not be successful, and thus the storage stability of the hydration product obtained will be poor. On the other hand, if it exceeds 0.4 mol, the amount thereof increases and the boiling water resistance and steam sterilization resistance of the resulting aqueous coating film tend to decrease. If the proportion of alcohol is less than 0.5 mol,
The solubility of the obtained resin is inferior, and when it exceeds 20 mol, the excess must be removed at the time of production, which is not practical.

In the present invention, when producing an oxycarboxylated and alkyl etherified amino resin, it is essential to simultaneously condense the raw material polyhydroxycarboxylic acid with an alcohol. Conventionally, this is a two-step process of co-condensing a compound such as polyhydroxycarboxylic acid after producing an alkyl ether compound, which is complicated in terms of production. Further, when the polyhydroxycarboxylic acid and the alcohol are simultaneously condensed, a catalyst may be used, but a tin compound such as dibutyltin oxide or monobutyltin oxide may be used as a catalyst. In that case, the amount of the tin compound used is 0.001 to 3 parts by weight based on 100 parts by weight of the total raw materials.

In the present invention, as a method for producing an oxycarboxylated and alkyl etherified amino resin, a predetermined amount of amino compound, formaldehyde, polyhydroxycarboxylic acid and alcohol and, if necessary, amine are charged and heated to form methylol. After further adding an acid catalyst and a tin compound as necessary and simultaneously condensing polyhydroxycarboxylic acid and alcohol while dehydrating, the reaction system is treated with a basic compound such as triethanolamine and aqueous sodium hydroxide solution. It is neutralized, and if necessary, dealcoholized to a predetermined concentration under normal pressure or reduced pressure.

Thus, an oxycarboxylated and alkyl etherified amino resin is obtained, and the carboxyl group in this amino resin is neutralized with a basic compound such as dimethylethanolamine, diethylethanolamine, triethylamine or ammonia, The target aqueous resin can be obtained. When this water-based resin is diluted with water, it can maintain a very good water dispersion state for a long period of time. The period depends on the water dilution and the temperature, but it does not change even if it is held at 40 ° C for 6 months.

In the present invention, when an aqueous resin composition comprising an oxycarboxylated and alkyl etherified amino resin is used in a paint or the like, it is useful as a curing agent. In this case, the resin serving as the main component includes acrylic resin, epoxy resin, polyester resin, alkyd resin, polyamide, etc., and is not particularly limited as long as the resin itself has water solubility or water dispersibility. As the mixing ratio of these resins and the water-based resin, the main component / hardening agent = (40/60) to (90/10) (weight ratio) in terms of solid content is suitable.

When the coating composition thus obtained is used as a sealer and a base coat coating, a metal pigment, a coloring pigment and the like may be added in a predetermined amount. In addition, other commonly used additives for paints such as a flow control agent, a dispersant, a surface control agent, a defoaming agent, an ultraviolet absorber, an antistatic agent and an antioxidant may be added. When it is used as a clear coat, a small amount of pigment may be added so that the hiding property is not fully developed.

When the aqueous resin composition comprising the oxycarboxylated and alkyl etherified amino resin of the present invention is used as a curing agent for paints, the above components are blended by a general method and diluted with water or a solvent. The viscosity is adjusted to form a paint, which is applied, and then a coating film is formed by heating at room temperature or by heating. As a coating method, a usual method, for example, bar coater coating, brush coating coating, spray coating or dip coating can be mentioned.

[0018]

The present invention will be described in detail below with reference to Reference Examples, Examples and Comparative Examples. In the following, "part" and "%" are based on weight.

Reference Example 1 A four-necked flask (with a stirrer, a thermometer, an external heater, a reflux condenser and a gas introduction tube) was charged with 187 parts (1.0 mol) of benzoguanamine, 113 parts (3.0 mol) of 80% paraformaldehyde, and a diether. 40 parts (0.3 mol) of methylolpropionic acid, 593 parts (8.0 mol) of n-butyl alcohol, and 1 part of triethanolamine were charged, and the temperature was raised to 100 ° C. After that, the mixture was kept at 100 ° C for 1 hour to perform methylolation, 0.1 part of dibutyltin oxide and 1 part of paratoluenesulfonic acid were added, condensation was carried out for 3 hours while dehydration was carried out under reflux, and neutralization was carried out with triethanolamine. Then, n-butyl alcohol was distilled off under reduced pressure to obtain an oxycarboxylated and alkyl etherified amino resin. The obtained resin had a nonvolatile content of 90%. Next, 14 parts of dimethylethanolamine and 215 parts of butyl cellosolve were charged into a flask containing this amino resin, and amine neutralization was carried out to obtain an aqueous resin (a-1). The resin obtained had a nonvolatile content of 70% and a viscosity (Gardner No./25
C) Z. The types and proportions of the above raw materials are shown in Table 1.
Put together.

Further, this resin (a-1) was evaluated by the following tests and measurements, and the results are shown in Table 3.・ Stability: Add 20 g of aqueous resin to a beaker (200 ml), dilute with 5 volumes of water at room temperature, immediately after that and at 40 ° C.
After being kept for 6 months in, the dispersion state of this product was visually observed and evaluated in two stages. Good: Poor, bad: Weight average molecular weight (Mw): Gel permeation chromatography (GPC). Shodex GPC-System-11 (trade name, manufactured by Showa Denko KK). -Particle size: A water dilution of an aqueous resin. Submicron particle size analyzer (Coulter, model number N4-MD).

Reference Examples 2 to 7 and Reference Example 9 In Reference Example 1, the same operation was performed with the kinds and proportions of the raw materials shown in Tables 1 and 2, and the aqueous resin (a-2)
~ (A-7) and (a-9) were obtained. Furthermore, these seven kinds of resins were evaluated by the above-mentioned tests and measurements, and the results are shown in Table 3.

Reference Example 8 In the same flask as used in Reference Example 1, 187 parts (1.0 mol) of benzoguanamine and 80% paraformaldehyde 150 were added.
Parts (4.0 mol), dimethylolpropionic acid 40 parts (0.3 mol), methyl alcohol 256 parts (8.0 mol), and triethanolamine 1 part were charged and the temperature was raised to the reflux temperature. After that, the mixture was maintained at reflux temperature for 1 hour to perform methylolation, 0.1 part of dibutyltin oxide and 1 part of paratoluenesulfonic acid were added, and alkylation was performed for 3 hours at reflux, neutralized with triethanolamine, and depressurized. Methyl alcohol was distilled off underneath to obtain an oxycarboxylated and alkyl etherified amino resin. Next, add dimethylethanolamine to the flask containing this amino resin.
14 parts and 215 parts of butyl cellosolve were charged and amine neutralization was carried out to obtain an aqueous resin (a-8). Further, this resin was evaluated by the above test and measurement, and the results are shown in Table 3.
Shown in

Reference Example 10 In the same flask as used in Reference Example 1, 187 parts (1.0 mol) of benzoguanamine and 80% paraformaldehyde 150 were added.
Parts (4.0 mol) and methyl alcohol 320 parts (10.0 mol)
Was charged and the temperature was raised to the reflux temperature. Then, the mixture was kept at the reflux temperature for 1 hour for methylolation, 0.8 part of oxalic acid was added, and the reaction was carried out for 1 hour at the reflux state to distill off methyl alcohol to make the nonvolatile content 70%. Then, in another flask the same as above, 142 parts of the resin obtained above, 10 parts of dimethylolpropionic acid and bisol 10EN
[Brand name, manufactured by Toho Chemical Industry Co., Ltd., 10 parts of polyether diol {addition product of polyethylene glycol (decamer) to bisphenol A}] was charged and reacted at 110 ° C. for 3 hours to be glycol etherified and oxycarboxylated. And an alkyl etherified amino resin were obtained. Further, 6.6 parts of dimethylethanolamine and 215 parts of butyl cellosolve were charged into the flask containing the amino resin, and the amine was neutralized to obtain an aqueous resin (a-10). Further, this resin was evaluated by the above tests and measurements, and the results are shown in Table 3.

[0024]

[Table 1] Composition unit: The upper value is part and the lower () value is mol.

[0025]

[Table 2] Composition unit: The upper value is part and the lower () value is mol.

[0026]

[Table 3]

Example 1 Almatex WA-911 (trade name, manufactured by Mitsui Toatsu Chemicals,
Acrylic resin, nonvolatile content 60%) was neutralized with dimethylethanolamine in an equivalent amount. This resin and water-based resin (a
-1) with 70/30 (weight ratio) in terms of solid content, diluted with water and adjusted to a nonvolatile content of 30-40%,
Got the paint. Using this paint, a tin plate (JIS-G-3303) was coated with a bar coater so that the dry film thickness was 10 μm, and baked at 240 ° C. for 90 seconds to obtain a test plate. The coating film of this test plate was evaluated by the following tests, and the results are shown in Table 4. -Boiling water resistance: After the test plate was immersed in boiling water for 1 hour, the coating film surface was visually observed and evaluated in three levels. ○ ・ ・ ・ Good, △ ・ ・ ・ Slightly bad (slight gloss and blister are generated) × ・ ・ ・ Poor (Gloss and blister are generated) ・ Steam sterilization resistance: The test plate is a high-pressure steam sterilizer (1.5 Kg/
After being left to stand for 30 minutes at (cm ² , 127 ° C.), the coating film surface was visually observed and evaluated in three levels. ○ ・ ・ ・ Good, △ ・ ・ ・ Slightly bad (slight gloss and blister are generated) × ・ ・ ・ Poor (Gloss and blister are generated)

Examples 2 and 3 and Comparative Examples 1 to 7 In Example 1, the aqueous resins (a-2), (a-3),
And (a-4) to (a-10) were each used in the same manner as above to obtain a coating material and further a test plate. The coating films of these 9 types of test plates were evaluated by the above test,
The results are shown in Tables 4 and 5.

[0029]

[Table 4]

[0030]

[Table 5] *: Since a precipitate was generated during the dilution with water, the operation thereafter was stopped.

[0031]

According to the present invention, the resulting oxycarboxylated and alkyl etherified amino resin has a stable dispersibility in water for a long period of time, and a composition comprising this resin is resistant to A coating film having excellent boiling water resistance and steam sterilization resistance can be formed. Further, in the present invention, the amino resin can be produced in a one-step process, which is not complicated as in the conventional case, which is industrially advantageous.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keisuke Obata 1900 Togo, Mobara-shi, Chiba Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Tsukasa Murakami 1900 Togo, Mobara-shi, Chiba Mitsui Toatsu Chemical Co., Ltd.

Claims (7)

[Claims] 1. An aqueous resin composition comprising an oxycarboxylated and alkyl etherified amino resin obtained by reacting an amino compound, formaldehyde, polyhydroxycarboxylic acid and alcohol. 2. The aqueous resin composition according to claim 1, wherein the amino compound is benzoguanamine and / or melamine. 3. The aqueous resin composition according to claim 1, wherein the alcohol is an aliphatic alcohol having 3 to 20 carbon atoms, an alicyclic alcohol or an aromatic alcohol. 4. The aqueous resin composition according to claim 1, wherein the polyhydroxycarboxylic acid is dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolvaleric acid, and / or gallic acid. 5. The oxycarboxylated and alkyl etherified amino resin comprises formaldehyde of 1.0 to 10 moles and polyhydroxycarboxylic acid based on 1 mole of the amino compound.
The aqueous resin composition according to claim 1, which comprises 0.05 to 0.4 mol and 0.5 to 20 mol of alcohol. 6. The method of claim 5, wherein the polyhydroxycarboxylic acid and the alcohol are simultaneously condensed with or without a catalyst in the production of the oxycarboxylated and alkyl etherified amino resin. Aqueous resin composition. 7. The catalyst is dibutyltin oxide and / or monobutyltin oxide.
The aqueous resin composition according to item 1.