JPH0320318A - Production of water-dilutable alkyl-etherified amino resin and water-based coating agent - Google Patents

Abstract

PURPOSE:To obtain a water-based coating agent excellent in curability and the water resistance and flexibility of a coating film by using an etherified product of an addition condensation product of formaldehyde with a reaction product of dicyandiamide with a specified biscyanoethyl spirocompound. CONSTITUTION:Dicyandiamide is reacted with 3,9-bis(cyanoethyl)-2,4,8,10- tetraoxaspiro[5.5]undecane in a molar ratio in the range of (2.0-3.)/1.0, desirably (2.0-2.5)/10 at 80-150 deg.C for 1-5hr under an alkaline condition, and the product sprioguanamine is reacted by addition with formaldehyde in a molar ratio in the range of 1/30-1/4, desirably 1/20-1/10 at 50-80 deg.C for 2-10hr. The obtained adduct is etherified with a 3C or lower alcohol to obtain a water-dilutable alkyl-etherified amino resin used for a water-based coating agent, an adhesive, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a water-dilutable alkyl etherified amino resin useful for paints, adhesives, etc., and to a water-based paint.

(Prior Art) In the past, paints and adhesives were mainly dissolved in large amounts of organic solvents, which caused problems. During use, these organic solvents are discharged into the atmosphere without being recovered in most cases.

In the paint field, water-based paints have traditionally been mainly so-called primer paints, such as electrocoated paints, and have been put into practical use particularly from the viewpoint of fire prevention and rationalization of painting. With the elimination of aromatic hydrocarbons (which are thought to be involved in the production of water-soluble paints) becoming more important, there has been a strong desire to expand the use of water-soluble paints through technological review.

In water-based paints containing amino resin as a curing agent,
As the amino resin, methyl etherified melamine resin is mainly used because of its water solubility. However, typical water-based paints using hexamethoxymethylolmelamine can provide coatings with good flexibility, but have the problem of poor water resistance.

Amino resins with a low degree of addition have problems with resin stability, and amino resins with a large amount of residual methylol groups have problems with paint stability and coating film flexibility. 1.
Alkyl etherified subiguanamine resins have the disadvantage of being very expensive.

(Problems to be Solved by the Invention) The present invention solves these problems. We provide a method for producing a specific alkyl etherified amino resin as an amino resin, and use the alkyl etherified amino resin obtained by this production method to produce a coating film with excellent water resistance and flexibility compared to conventional spiroguanamine. The objective is to provide an inexpensive water-based paint that has superior curability and water dilutability compared to those using resins.

(Means for Solving the Problems) That is, the present invention provides dicyandiamide and 24.8,1
A water dilution characterized by adding the reaction product A obtained by reacting 0-tetraoxaspiro[5]undecane in the presence of an alkali with formaldehyde, condensing it, and etherifying it with an alcohol having 3 or less carbon atoms. The present invention relates to a method for producing alkyl etherified amino resin and a water-based paint containing the water-dilutable resin obtained by the method.

Dicyandiamide of the present invention and a9-bis(cyanoethyl)-2.4,ato-tetraoxaspiro(5.5
) The reaction with undecane is already known, and by appropriately selecting reaction conditions, the two reactants A can be easily combined (for example, % Publication No. 8676/1986). That is, the reactant A obtained in this reaction is 9-bis(2-(2,4-diamino-1,3.5-}reaza-6-phenyl)ethyl)-2.4,a,10-tetraoxaspiro [5.
5 ] Undecane (hereinafter abbreviated as spiroguanamine) is the main component, and it also contains small amounts of by-products.

Normally (for example, Japanese Patent Publication No. 44-8676, etc.), this by-product is collected from person to person to obtain subiguanamine. F
Another disadvantage is that the cost of the material increases significantly due to the addition of a drying process.

The present inventors surprisingly discovered that even when these by-products are converted into a resin without removing them, they can be used satisfactorily as a water-dilutable resin, and furthermore, they have the advantage of improving water dilutability. It was.

Reactant A in the present invention is, for example, dicyandiamide/
The molar ratio of 3,9-bis(cyanoethyl)-2.4,8.10-tetraoxasbiro(5.5)undecane is 2.
0-3. 0/1. It is preferable that the reaction be carried out in the range of zO to 2. 5/1.
It is more preferable to react in a range of 0. When the ratio of dicyandiamide exceeds 3.0, the amount of remaining dicyandiamide increases, and when it is made into a resin and further used as a paint, it tends to have poor water resistance. As for reaction conditions, it is preferable to react at a temperature of 80 to 150°C for 1 to 5 hours.

Formaldehyde is added to the reaction product thus obtained. As for the reaction conditions, it is preferable to carry out the addition reaction at a temperature of 50 to 80°C for 2 to 10 hours. It is preferable that the spiroguanamine/formaldehyde (molar ratio) in the reactant A is in the range of 1/30 to 1/4.
A range of /20 to 1/10 is preferable.

The water-dilutable alkyl etherified amino resin of the present invention is obtained by further alkyl etherifying the above-mentioned adduct with an alcohol having 3 or less carbon atoms (methanol, ethanol, propanol, or impropanol), and furthermore, the water-dilutable alkyl etherified amino resin is obtained by alkyl etherification with an alcohol having 3 or less carbon atoms (methanol, ethanol, propanol, or impropanol). Through a reaction, the molecular weight is adjusted to suit the purpose. When an alcohol having 4 or more carbon atoms is used, the water solubility is 1 or the water dispersibility is poor. The amount of alcohol used is such that the spiroguanamine/alcohol (molar ratio) in reactant A is 1/50.
The range is preferably 1/5 to 1/5.

The water-dilutable alkyl etherified amino resin of the present invention can be produced by various methods.

For example, reactant A. Mix formaldehyde and methanol. A method of heating under alkaline conditions (preferably pH 9 to 11) to carry out an addition reaction, then heating under acidic conditions (preferably pH 2 to 5) to carry out condensation and alkyl etherification reactions, reactant A There is a method in which formaldehyde and methanol or water are mixed, heated under alkaline conditions, subjected to an addition reaction, the resulting formaldehyde adduct is once isolated, methanol is added thereto, and the mixture is heated under acidic conditions.

The water-soluble or water-dispersible resin in the present invention is not particularly limited as long as it reacts with the water-dilutable alkyl etherified amino resin used in the present invention, but examples include water-soluble or water-dispersible alkyd resins, water-soluble Alternatively, there are water-dispersible acrylic resins.

The above water-soluble or water-dispersible alkyd resins are. For example, it is a neutralized product of an alkyd resin obtained by reacting a polycarboxylic acid, a polyhydric alcohol, and, if necessary, an oil or a fatty acid thereof. Polyhydric carboxylic acids include phthalic acid,
Isophthalic acid, terephthalic acid, tetrahydrophthalic acid,
These include maleic acid, 7"f acid, succinic acid, adivic acid, cepacic acid, trimellitic acid, and pyromellitic acid.

These may be used in the form of ester-forming derivatives such as acid anhydrides and methyl esters. Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol. Dipropylene glycol, neopentyl glycol. Examples include 1,4-butanediol, 1,6-hexanediol, trimethylene glycol, glycerin, trimethylolpropane, trimethylolethane, and pentaerythritol.

The oils are tung oil and linseed oil. Examples include soybean oil, dehydrated castor oil, safflower oil, castor oil, coconut oil, and tall oil. The alkyd resin can be produced by a known method.
When oil is used, oil and polyhydric alcohol are reacted at 200 to 260°C in the presence of a transesterification catalyst such as lithium hydroxide, and then a polybasic acid and the remaining polyhydric alcohol are added and the mixture is heated to 180 to 250°C. When no oil is used, there is a method in which the raw materials are mixed and reacted at 180 to 250°C.

The above-mentioned water-soluble or water-dispersible acrylic resins include acrylic acid, methacrylic acid. α with maleic acid and itaconic acid
, β-monoethylenically unsaturated carboxylic acid and acrylic acid 2
-Hydroxyethyl, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate. α having a hydroxy group such as 2-hydroxypropyl methacrylate
, a neutralized acrylic resin obtained by copolymerizing β-ethylenically unsaturated monomers and other unsaturated monomers. As for other unsaturated monomers. Methyl acrylate,
Alkyl esters of α,β-monoethylenically unsaturated carboxylic acids such as ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, n-butyl methacrylate, acrylamide, methacrylamide, N- Acrylamide derivatives such as methylol acrylamide, N-methylol methacrylamide, and diacetone acrylamide; glycidyl esters of α,β-monoethylenically unsaturated carboxylic acids such as glycidyl acrylate and glycidyl methacrylate; and saturated compounds such as vinyl acetate and vinyl blobionate. Examples include vinyl esters of carboxylic acids, aromatic unsaturated monomers such as styrene, α-methylstyrene, and vinyltoluene. The above copolymerization can be carried out by heating to 130 to 160°C in the presence of a radical catalyst such as azobisisobutyronitrile, penzoyl peroxide, dibutyl peroxide, cumene hydroperoxide.

Alkyd resins and acrylic resins before neutralization have an acid value of 20
It is preferable to adjust the hydroxyl value to 15 to 400. It is more preferable to adjust the acid value to 20 to 100 and the hydroxyl value to 15 to 200. If the acid value is too low, the water solubility or water dispersibility after neutralization will be poor, and if the acid value is too high, the coating properties will tend to deteriorate.

On the other hand, if the hydroxyl value is too small, the curability tends to be poor, and if it is too large, the water resistance of the coating film tends to be poor.

In order to make such alkyd resins and acrylic resins water-soluble or water-dispersible before neutralization, it is sufficient to neutralize the acid groups of the resins with a volatile base such as ammonia or amines. Examples of such amines include monobrobylamine, monobutylamine, dietheramine, dibutylamine. Triethylamine, tributylamine, monoethanolamine, ethylmonoethanolamine, monocyclohexylamine, morpholine. Biperidine like < 1st
Primary, secondary and tertiary aliphatic or cycloaliphatic amines can be used. Ammonia or amine is preferably used in an amount of 0.3 to 1.2 mol per equivalent of acid group.

In the present invention, the water-dilutable alkyl etherified amino resin (former) and the water-soluble or water-dispersible resin (latter) are:
(Former) / (Latter) weight ratio (solid content ratio) is 5795 ~
Preferably, the ratio is 60/40. If it exceeds this range, the coating properties such as the curability or flexibility of the coating film tend to be poor.

Further, a catalyst such as an inorganic acid such as hydrochloric acid or phosphoric acid, or an organic acid such as balatoluenesulfonic acid may be added to the aqueous paint of the present invention. The amount used is preferably 1 part by weight or less per 100 parts by weight (solid content) of the water-dilutable alkyl etherified amino resin.

The water-based paint of the present invention includes butylcellonulp, ethyl cellosolve, methyl cellosolve, diacetone alcohol, 3-
It can be used in a suitable solid content using a mixed solvent of water and a water-soluble solvent such as methoxy-3-methylphthanol, impropanol, ethanol, methanol, etc. The water-soluble organic solvent is preferably used in an amount of 5 parts by weight or more, particularly preferably 10 parts by weight or more, per 100 parts of water.

The water-based paint of the present invention may contain pigments and other additives depending on the purpose.

Further, as a coating method, spray coating, coating with a roll coater, coating, etc. can be adopted.

Next, manufacturing examples and examples related to the present invention will be shown.

In the following, parts and weights indicate parts by weight and quantities, respectively.

(Example) [Production Example 1] Dicyandiamide 176.89 (2.1 mol) was placed in a flask equipped with a stirrer, a reflux condenser, and a thermometer. 3.9-
Weigh out 266.79 (1.0 mol) of bis(cyanoethyl)-2, 8.10-tetraoxasbiro(5.5)undecane, butyl cellosolp 444a, and 8g of potassium hydroxide. ), after raising the temperature to 120℃, 4 at the same temperature
A time reaction was performed. After cooling (50°C), 80% paraformaldehyde (contains 20% water) 750.09 (20
mol), add 800 g (25 mol) of methanol, and add 60 g (mol) of methanol.
After raising the temperature to ℃, addition reaction was carried out at the same temperature for 4 hours. Then, 23g of 62% nitric acid was added to adjust the pH to 3.5. 7
The alkyl etherification reaction was carried out at 0°C for 10 hours.

After the reaction was completed, the reaction solution was again adjusted to alkalinity (pH 10.0) with 30% sodium hydroxide and concentrated under reduced pressure. The end point was 130°C (230 torr) and the amount produced at this time was ti7409. This resin was diluted with butyl cellosolp to adjust the nonvolatile content to 75%. The viscosity was U (Gardna/25°C).

[Production Example 2] Using the same equipment as Production Example 1, dicyandiamide 176
．． 89 (2.1 mol). 3.9-bis(cyanoethyl12,4,8.10-tetraoxasbiro[5.5]
Weigh out 266.79 (1.0 mol) of undecane, 444 g of butyl cellosolp, and 8 g of potassium hydroxide! ), 1
After raising the temperature to 20°C, the reaction was carried out at the same temperature for 4 hours. 50℃
After cooling to
25 mol) was added. After raising the temperature to 60℃. The addition reaction was carried out at the same temperature for 4 hours. Then, 239% of 62-eunitric acid was added, p
The H content was adjusted to 3.5, and the alkyl etherification reaction was carried out at 70°C for 10 hours. After the reaction was completed, the reaction solution was again adjusted to alkalinity (pH 10.0) with 30% sodium hydroxide. Then concentrated under reduced pressure (degree of reduced pressure 230 torr)
I did it. The end point was 130℃, and the amount of production at this time was 7
It was 20g. This resin was diluted with butyl cellosolve to adjust the nonvolatile content to 75%.

The viscosity was UV (Gardner 725°C).

[Production Example 3] Using the same equipment as Production Example 1, dicyandiamide 193
．． 79 (2-3 mol). 3.9-bis(cyanoethyl)-2.4,8.10-tetraoxasbiro[5.5
] Weigh out 266.79 (1 mol) of undecane, 444 g of butyl cellosolp, and 8 g of potassium hydroxide fi, 12
After raising the temperature to 0℃. The reaction was carried out at the same temperature for 4 hours. After cooling to 50°C, 750 g (20 mol) of 80% paraformaldehyde and 800 g (25 mol) of methanol were added, and after raising the temperature to 60°C, an addition reaction was carried out at the same temperature for 6 hours. then 62
239 mg of eunitric acid was added, the pH was adjusted to 3.5, and the alkyl etherification reaction was carried out at 70°C for 10 hours. After the reaction is complete, the reaction solution is again made alkaline with 30% sodium hydroxide (
The pH was adjusted to 10.0). After that, the concentration is reduced (degree of reduced pressure is 2)
30 torr). The birth rate at this time was 750.
It was g. Dilute this resin with butyl cellosolve,
The non-volatile content was adjusted to 75%.

The viscosity was W (Gardna/25°C).

[Production Example 4] Using the same equipment as Production Example 1. Dicyandiamide 193
．． 79 (Z3 mol), 3.9-bis(cyanoethyl)-
2.4,8.10-Tetraoxasbiro[5.5]undecane 266.79 (1.0 mol), butyl cellosolp 4449, and potassium hydroxide 8g were weighed out! ), 125
After raising the temperature to ℃, the reaction was carried out at the same temperature for 3 hours. After cooling to 50℃, 80% paraformaldehyde (contains 20% water)
7509 (20 mol) and methanol 3209 (10 mol) were added, the temperature was raised to 60'C, and addition reaction was carried out at the same temperature for 5 hours. Then add 62% nitric acid t-239 and adjust the pH to 3.
．． 5, and the alkyl etherification reaction was carried out at 70°C for 6 hours. After the reaction was completed, the reaction solution was again adjusted to alkalinity (pH 10.0) with 30% sodium hydroxide.

Thereafter, vacuum concentration (degree of vacuum: 230 torr) was performed.

The end point was 135°C, and the amount produced at this time was 7309. This resin was diluted with butylcellosolp to adjust the nonvolatile content to 75%. The viscosity was W (Gardna/25°C).

[Production Example 5] Using the same equipment as Production Example 1, dicyandiamide 193
．． 79 (23 mol), a9-bis(cyanoethyl)-2
．． 4, alo-tetraoxaspiro[5.5]undecane 266.7g (1.0 mol), butyl cellosolve 44
4 g of potassium hydroxide and 8 g of potassium hydroxide were weighed out, heated to 125° C., and then reacted at the same temperature for 3 hours. After cooling to 50℃,
80% paraformaldehyde (contains 20% water) s6
Z5s (15 mol), methanol 320 (10 mol)
was added, the temperature was raised to 60°C, and addition reaction was carried out at the same temperature for 5 hours.

Thereafter, 239 g of 62% nitric acid was added to adjust the pH to -35, and the alkyl etherification reaction was carried out at 70°C for 6 hours. After the reaction was completed, the reaction solution was again adjusted to alkalinity (pH 10.0) with 30% sodium hydroxide. Thereafter, vacuum concentration (degree of vacuum: 230 torr) was performed. 135
The end point was 745 g at this time. This resin was diluted with butyl cellosolve to adjust the nonvolatile content to 75%. The viscosity was UV (Gardner 725°C).

[Comparative Production Example 1] Using the same apparatus as Production Example 1, 80% paraformaldehyde (containing 20% water) 750.09 (20 mol),
800 g (25 moles) of methanol. 30% sodium hydroxide}
Weigh the IJum 169 and add a9-bis[2-(2
4-diamino-1,3.5-}reazor-6-phenyl)
ethyl]-su4,13.10-tetraoxaspiro(5
．． 3) Add U7detJ7432g (1 mol) and 60℃
After raising the temperature to , the addition reaction was carried out at the same temperature for 6 hours. then 6
Add 3.09% of 2% nitric acid. Adjust pH to a5 and heat to 70℃
The alkyl etherification reaction was carried out. After the reaction is complete, adjust the reaction solution to an alkaline pH with 30% sodium hydroxide and IJum.
10.0 and concentrated under reduced pressure. The amount produced at this time is 6
It was 309. This resin was diluted with butylcellosolp to adjust the nonvolatile content to 75%. The viscosity was y-z (Gardna/25°C).

Table 1 shows the water dilutability and by-product content of the alkyl etherified amino resins produced.

The water dilutability measurement method is as follows: hp.

Sample 109-i is weighed into a 200 cc Erlenmeyer flask.

Shake and stir this. When water is added dropwise, the required volume (1) of water to cause cloudiness is determined, and it is converted to the required volume (ml!) of water per 1 g of sample, and this converted value indicates water dilutability.

Therefore, the larger the numerical value of water dilutability, the better the material mixes (becomes compatible) with water and is superior in water dilutability.

Furthermore, the alkyl etherified amino resin and water-soluble acrylic resin (Hitachi Kakai Kogyo Co., Ltd. trade name: Hitaloid 7200K, solid content: SOS, solvent: water/isopropanol) button and titanium white of the production example were mixed in the formulation shown in Table 2. ，
Thinner after roll kneading (Kumii, Petyl Cellosolp/
Water = 10/90) was added and the viscosity was adjusted to 20 seconds (at 25°C) using food cup ◆4, and the film thickness was 30 to 40.
Coated plate (Bonderite ◆144) so that μ/Dry
) and leave it at room temperature for about 20 minutes.
Baked at 60°C for 20 minutes. Table 3 shows the performance of the resulting coating film.

Table 1 The test method for coating film performance is as follows.

The following (1) to (5) were performed according to JIS K 5400.

(1) Gloss Measured by 260 degree specular reflectance.

(2) Pencil hardness 2 Determined using Mitsubishi Pencil Uni.

(3) Cross cut: 1mm on the coating surface with a cutter knife
100 squares were cut at intervals of , and the number of squares remaining when peeled off with cellophane tape was judged.

(4) Erichsen value: Measured with an Erichsen tester.

(5) Impact value: DuPont impactor t/; - 5 0
Judgment was made in b centimeters according to 0.09.

(6) Boiling water resistance: After immersing in boiling water for 1 hour and then taking it out, the condition of the coating surface was visually judged.

○ No change △ Slightly immersed × Vigorously immersed (effects of the invention) The water-based paint using the water-dilutable alkyl etherified amino resin produced by the present invention has excellent water resistance and flexibility of the coating film. b. It's cheap.

Claims (1)

[Claims] 1. Dicyandiamide and 3,9-bis(cyanoethyl)
- Reactant A obtained by reacting 2,4,8,10-tetraoxaspiro[5,5]undecane in the presence of an alkali is added with formaldehyde, condensed, and etherified with an alcohol having 3 or less carbon atoms. A method for producing a water-dilutable alkylated etherified amino resin. 2. A water-based paint containing a water-dilutable resin obtained by the production method according to claim 1. 3. The water-based paint according to claim 2, further comprising a water-soluble or water-dispersible resin.