JPH10279646A - Alkyl-etherified benzoguanamine-formaldehyde resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alkyl-etherified benzoguanamine-formaldehyde resin which has a sufficient water solubility and low fuming properties by synthesizing the resin so that the content of mononuclear compds. is lower than that of dinuclear compds. and the content of polynuclear compds. having 4 or higher nuclei is lower than a specified value. SOLUTION: 1 mol of benzoguanamine, 1.0-2.0 mol of formaldehyde, 1-10 mol of an alcohol, and 1.0-3.0 mol of water are mixed, and the resulting mixture is heated under an alkaline condition (at a pH of 9-11) to 50-100 deg.C to be subjected to methylolation, then heated under an acidic condition to 50-65 deg.C to be subjected to condensation and etherification, and subjected to solvent removal under a reduced pressure under an alkaline condition (at a pH of 9-11) to give an alkyl-etherified benzoguanamine-formaldehyde resin wherein the content of mononuclear compds. is lower than that of dinuclear compds. and the content of polynuclear compds. having at least four nuclei is 45 wt.% or lower. The alcohol used as the alkyl-etherifying agent is a 1-4C alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkyl etherified benzoguanamine formaldehyde resin which is suitable mainly for paints, adhesives, paper impregnating agents and the like.

[0002]

2. Description of the Related Art In recent years, it has been desired to reduce the amount of organic solvent discharged when coating films for automobiles, industrial machines, steel furniture, and the like, and the conventional solvent-based paints are shifting to aqueous. .

In a water-based paint containing an amino resin as a curing agent, an alkyl etherified melamine resin or the like is used as the amino resin from the viewpoint of water solubility. However, aqueous paints using an alkyl etherified melamine resin have good solubility in water or a water-miscible solvent, but have a problem of poor water resistance in a cured coating film.

On the other hand, aqueous paints using alkyl etheneated benzoguanamine resins have poor solubility in water or water-miscible solvents and have a problem in paint stability.

[0005] As a solution to the above problem, there has been proposed an aqueous paint or an improvement in aqueous dispersion using an amino compound composed of melamine and benzoguanamine. In addition, those with a high mononuclear content are used to obtain water solubility, but low molecular weight substances are scattered from the amino resin during baking,
It adheres and solidifies in the baking furnace, falls on the object to be coated, and causes problems such as occurrence of defective products and frequent cleaning of the furnace, and thus satisfactory performance has not been obtained.

[0006]

The invention according to claim 1 provides an alkyl etherified benzoguanamine formaldehyde resin which exhibits sufficient water solubility and low fume properties and is suitable for paints, adhesives, paper impregnating agents and the like. Is what you do.

[0007]

According to the present invention, there is provided an alkyl ether having a mononuclear content of less than a binuclear content and a polynuclear content having 4 or more nuclei of not more than 45% by weight. Benzoguanamine formaldehyde resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An amino resin is obtained by converting an amino compound such as melamine or benzoguanamine into methylol by reaction with formaldehyde and then etherifying by dehydration condensation with an alcohol.

The alkyl etherified benzoguanamine formaldehyde resin obtained by the production method of the present invention is intended to improve the water solubility and low fume properties of the amino resin, and the content of mononuclear is reduced to that of binuclear. If the amount is more than the amount, the fume amount increases, and if the content of the polynuclear body having 4 or more nuclei exceeds 45% by weight, the solubility in water or a water-miscible solvent is poor, and the paint stability is poor.

Hereinafter, the production method of the present invention will be described.
An amino compound such as benzoguanamine, an alcohol, formaldehyde, and water are mixed, and the mixture is made alkaline (preferably,
pH 9 to 11), the mixture is heated to 50 to 100 ° C. to cause a methylolation reaction, and then heated to 50 to 65 ° C. under acidity for condensation and etherification, and then alkaline (preferably,
The target resin is obtained by a method of removing the solvent under reduced pressure under pH 9 to 11). In this way, in the production, 1.0 to 2.0 mol of formaldehyde, 1 to 10 mol of alcohol, preferably 1 to 4 mol, per 1 mol of benzoguanamine,
1.0-30.0 mol of water, preferably 5.0-20.0
Used in molar proportions.

[0011] Methylolation of the amino compound can be carried out with formaldehyde, and formalin, paraformaldehyde and the like are used as a formaldehyde source.

As the alkyl etherifying agent, an alcohol having 1 to 4 carbon atoms such as methanol, ethanol, propanol and butanol is used for the object of the present invention.

The composition for a coating material can be prepared by blending a resin (B) (for example, a resin having a hydroxyl group) capable of reacting with the alkyl etherified benzoguanamine formaldehyde resin (A) of the present invention. it can. In this case, the mixing ratio (weight ratio) of (A) / (B) is 20 / 80-
80/20 is preferable from the viewpoint of curability.

[0014]

The present invention will be described below with reference to examples. In the following, parts means parts by weight and% means% by weight. Example 1 80 flasks with stirrer, reflux condenser and thermometer
% Paraform, 78.0 parts of methanol, 128.0 parts of methanol and 2.0 parts of a 50% aqueous sodium hydroxide solution were added to dissolve paraformaldehyde, and then benzoguanamine 18 was added.
After adding 7.0 parts, the reaction was carried out at 60 ° C. for 3 hours. Then, after adding 4.0 parts of 62% nitric acid, 30 mol of water was charged and reacted at 60 ° C. for 4 hours. After the reaction is completed,
The reaction solution was made alkaline with 2.0 parts of a 2.0% aqueous sodium hydroxide solution and concentrated under reduced pressure (50 torr). The end point was when the temperature in the flask reached 110 ° C. At the same time as the end point, 125 parts of isopropyl cellosolve was added and the heating residue was 7
It was adjusted to be 0%. The amount of the resulting methyl etherified benzoguanamine resin was about 405 parts and the viscosity was Z ₃ in Gardner viscosity.

Example 2 80 flasks were equipped with a stirrer, reflux condenser and thermometer.
% Paraform 37.5 parts, methanol 64.0 parts and 5
After adding 2.0 parts of 0% aqueous sodium hydroxide solution to dissolve paraformaldehyde, benzoguanamine 18 was added.
After adding 7.0 parts, the reaction was carried out at 60 ° C. for 3 hours. Then, after adding 4.0 parts of 62% nitric acid, 30 mol of water was charged and reacted at 60 ° C. for 4 hours. After the reaction is completed,
The reaction solution was made alkaline with 2.0 parts of a 2.0% aqueous sodium hydroxide solution and concentrated under reduced pressure (50 torr). The end point was when the temperature in the flask reached 110 ° C. At the same time as the end point, 125 parts of isopropyl cellosolve was added and the heating residue was 7
It was adjusted to be 0%. The amount of generated methyl etherified benzoguanamine resin was about 380 parts, the viscosity was Z ₅ in Gardner viscosity.

Production Example 1 (Water-soluble acrylic resin solution) 200 parts of butyl cellosolve are placed in a reaction vessel equipped with a stirrer and kept at 120 ° C under a nitrogen stream. A mixture of 60 parts of styrene, 60 parts of ethyl acrylate, 30 parts of butyl acrylate, 60 parts of methyl methacrylate, 60 parts of 2-hydroxyethyl methacrylate, 30 parts of acrylic acid and 6 parts of azobisisobutyronitrile was dropped from the dropping tube for about 2 hours. One part of azobisisobutyronitrile was added three times every two hours after completion of the dropwise addition, and the mixture was further reacted for 2 hours to obtain an acrylic resin solution having a nonvolatile content of 60%. Then, dimethylethanolamine 37 was added to the acrylic resin solution.
And 500 parts of ion-exchanged water, and water in the system was substantially distilled off under reduced pressure to obtain a water-soluble acrylic resin solution having a nonvolatile content of about 60%.

Comparative Example 1 A flask equipped with a stirrer, a reflux condenser and a thermometer was charged with 80
% Paraform, 70.0 parts of methanol, 960.0 parts of methanol and 2.0 parts of a 50% aqueous sodium hydroxide solution were added to dissolve paraformaldehyde, and then benzoguanamine 18 was added.
After adding 7.0 parts, the reaction was carried out at 60 ° C. for 3 hours. Thereafter, 4.0 parts of 62% nitric acid was added and reacted at 60 ° C. for 1 hour. After completion of the reaction, 2.0 parts of a 50% aqueous sodium hydroxide solution was again made alkaline with the reaction solution, and the solution was reduced under reduced pressure (50
rr). The end point was when the temperature in the flask reached 110 ° C. At the same time as the end point, 125 parts of isopropyl cellosolve was added to adjust the heating residue to 70%.
The amount of the resulting methyl etherified benzoguanamine resin is about 3
80 parts and the viscosity was Y in Gardner viscosity.

Comparative Example 2 A flask equipped with a stirrer, a reflux condenser and a thermometer was charged with 80
% Paraform, 70.0 parts of methanol, 960.0 parts of methanol and 2.0 parts of a 50% aqueous sodium hydroxide solution were added to dissolve paraformaldehyde, and then benzoguanamine 18 was added.
After adding 7.0 parts, the reaction was carried out at 60 ° C. for 3 hours. Thereafter, 10.0 parts of 62% nitric acid was added and reacted at 70 ° C. for 4 hours. After completion of the reaction, 8.0 parts of a 50% aqueous sodium hydroxide solution was again made alkaline with the reaction solution, and the solution was reduced under reduced pressure (50%).
torr). The end point is when the temperature in the flask is 110 ° C
And when it reaches. At the same time as the end point, 125 parts of isopropyl cellosolve was added to adjust the heating residue to 70%. The amount of the resulting methyl etherified benzoguanamine resin was about 380 parts and the viscosity was Z _{5 to} Z ₆ in Gardner viscosity.

GPC of the methyl etherified benzoguanamine resin obtained in Examples 1 and 2 and Comparative Examples 1 and 2
Was measured under the following measurement conditions, and the contents (% by weight) of each body are shown in Table 1.

Column: Gelpac410, manufactured by Hitachi Chemical Co., Ltd. Solvent: THF Flow rate: 0.5 ml / min Temperature: 40 ° C. Sample concentration: 0.5 g / 10 ml (THF) Injection volume: 200 μl Detector: differential refractometer

[0021]

[Table 1]

Example 3 57.1 parts of the amino resin of Example 1 and 100 parts of the water-soluble acrylic resin of Production Example 3 were mixed with a thinner (composition: butyl cellosolve / water = 10/90) in a Ford cup # 4 for 30 seconds. The paint viscosity was adjusted to be as follows.

Example 4 and Comparative Examples 3 and 4 Using 57.1 parts of the amino resin of Example 2 or Comparative Examples 3 and 4, the water-soluble acrylic resin 10 of Production Example 3 was prepared in the same manner as described above.
0 parts were thinner (composition; butyl cellosolve / water = 10 /
90), the paint viscosity was adjusted to 30 seconds with Ford Cup # 4.

The results of the water dilutability and fume properties of the paints obtained in Examples 3 and 4 and Comparative Examples 3 and 4 are shown in Table 2.

[0025]

[Table 2]

The fuming test method is as follows. After coating on a tin plate, the plate was baked in an oven at 200 ° C. for 10 minutes, and fumes generated were observed. ：: No fuming occurred. X: The occurrence of fuming is large.

[0027]

The alkyl etherified benzoguanamine formaldehyde according to claim 1 has sufficient water solubility and low fume properties, and is suitable for paints, adhesives, treatment agents for paper impregnation and the like.

Claims (1)

[Claims] 1. An alkyl etherified benzoguanamine formaldehyde resin having a mononuclear content of less than a binuclear content and a polynuclear content of 4 or more nuclei of not more than 45% by weight.