JPS62270667A - Production of aqueous dispersion of aminoplast - Google Patents

Abstract

PURPOSE:To make dispersion in water easy and to enable a coating film having excellent resistance to water and chemicals, crosslinkability, etc. to be formed, by co-condensing a specified amount of a hydrophilic urethane compd. in the production of an aminoplast by reacting a compd. having an amino group with an aldehyde compd. and a lower alcohol. CONSTITUTION:In the production of an aminoplast which is partially or fully etherified with a 1-4C lower alcohol by reacting at least one compd. (A) having an amino group selected from the group consisting of urea, melamine, benzoquanamine, etc., with at least one aldehyde compd. (B) selected from the group consisting of formaldehyde, paraformaldehyde, glyoxal, etc., and a 1-4C lower alcohol (C), 1-30pts. hydrophilic urethane compd. (D) is added to 100pts. (on a solid basis) of the combined amount of the components A, B and C and a co-condensation reaction is carried out. Water is added to the resulting co-condensation solution to carry out dispersion in water by removing the solvent or without removing the solvent.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention has good water dilutability even when used alone, and is suitable for use in water-soluble or water-dispersible alkyd resins, acrylic resins, and oil-free resins. When used as a curing agent for alkyd resins or mixed with these resins, it can be diluted with water almost infinitely, has excellent storage stability, and the resulting coating has excellent hardness, chemical resistance, especially alkali resistance, and water resistance. The present invention relates to a method for producing an aqueous aminoplast dispersion having excellent properties.

[Prior art and its problems]

Conventionally, formaldehyde is reacted with urea, melamine, acetoguanamine, benzoguanamine, etc.

Next, as a water-soluble aminoplast obtained by reacting a C1-4 lower alcohol, methyl etherified melamine using methyl alcohol as the lower alcohol is used.
Formaldehyde resins, methyl etherified urea-formaldehyde resins, etc. are known. When the degree of condensation is low, these substances have high solubility in water, but when the degree of condensation is high, they become hydrophobic and tend to become cloudy and separate easily.

Furthermore, when etherification is performed using lower alcohols other than methyl alcohol, such as isopropyl alcohol, isobutanol, and n-butanol, the solubility in water decreases, resulting in cloudiness, separation, or water dispersion. It tends to be impossible. On the other hand, when using aminoplast alone or in combination as a crosslinking agent for other resins, it is possible to increase the degree of condensation of aminoplast or to perform etherification using a more hydrophobic alcohol other than methyl alcohol. It is recognized that the properties of the obtained aminoplast, such as water resistance, chemical resistance, and crosslinking properties, can be improved by using the above method.

However, although such hydrophobic aminoplasts are usually dissolved in a solvent such as quiziol and used as a wave yim compound for a solvent solution, it is extremely difficult to use them as a water-based coating composition.

When a large amount of emulsifier is used in the above-mentioned hydrophobic aminoplast to forcibly disperse it in water.

The coating obtained from the aminoplast aqueous dispersion is water resistant,
Durability such as chemical resistance is significantly reduced, and the only product that can be obtained is one that significantly reduces the effect of making aminoplast hydrophobic.
It was extremely unsatisfactory.

[Problem that the invention seeks to solve]

As a result of intensive studies in view of the above-mentioned current situation, the present inventors produced an aminoplast partially or completely etherified with a lower alcohol by reacting an amino group-containing compound, an aldehyde compound, and a lower alcohol. When co-condensing a specific amount of a specific hydrophilic urethane compound, an aminoplast can be formed into a coating that is extremely easy to disperse in water and has excellent properties such as water resistance, chemical resistance, and crosslinkability. The present inventors have discovered that an aqueous dispersion of the following can be obtained, and have completed the present invention.

[Structure of the invention]

To summarize the present invention, the present invention comprises [A] urea, melamine,
One or more amino group-containing compounds selected from the group consisting of acetoguanamine, benzoguanamine, steroguanamine, or spiroguanamine, [B] consisting of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and glyoxal. One or more aldehyde compounds selected from the group and a [C]Ct~4 lower alcohol are reacted to obtain an aminoplast partially or completely etherified with a C1~4 lower alcohol. On the occasion of
[D] Hydrophilic urethane compound as described above [A], [B]',
and a step of adding 1 to 30 parts to 100 parts of the solid content obtained from [C] for co-condensation.

a step of adding water to the obtained cocondensation liquid to create an aqueous dispersion;
The present invention relates to a method for producing an aqueous aminoplast dispersion, which is characterized by combining a solvent removal step if desired.

Hereinafter, the configuration of the present invention will be explained in detail.

Compounds having an amino group as component [A] used in the present invention include urea and melamine.

It is one or more selected from the group consisting of acetoguanamine, benzoguanamine, steroguanamine, and spiroguanamine. In particular, urea, melamine, benzoguanamine alone or a mixture thereof are preferably used from the viewpoint of cost, crosslinkability, etc.

The aldehyde compound used as the [B] acid component used in the present invention is one or more selected from formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, butyladehyde, and glyoxal.

Regarding the aldehyde component, formaldehyde, paraformaldehyde, and glyoxal are preferably used alone or in a mixture thereof from the viewpoint of cost and reactivity.

The lower alcohol as the [C] component used in the present invention is necessary for stabilizing the reaction product from the compound having an amino group and the compound having an aldehyde group. -4 lower alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol.

Examples include isobutyl alcohol and t-butyl alcohol, and either of these is usually used alone or in combination.

Among them, n-butyl alcohol, isobutyl alcohol, and isopropyl alcohol are particularly preferably used in terms of reactivity, cost, crosslinkability of the resulting aminoplast, and the like.

Next, the hydrophilic urethane compound as component [D], which is an essential reaction component in the novel method for producing an aminoplast aqueous dispersion according to the present invention, will be explained.

[D] The hydrophilic urethane compound as the component is (a) a monohydroxy compound having the general formula no -(x)m-(y)n-111, (b) an organic isocyanate compound,
and (c) an active hydrogen-containing compound reactive with the incyanate group to form a compound (a) No-01 (group), (b) No-N
GO group and (c) (71-) group are -OH/-NC
It is obtained by reacting at a ratio of O/-H=1/1 to 410 to 3 (equivalent ratio).

In the general formula of the monohydroxy compound (a), R
is an alkyl group of C0~2°, X and Y may each be the same or different, and include an essential oxyethylene unit, the oxyethylene unit, oxypropylene unit,
Or a combination with any one oxybutylene unit, where m and rl indicate the number of repeating units. In the present invention, among the compounds represented by the above general formula, the total molecular weight of oxyethylene units is 1500 to 1500.
0, and the total weight of the oxyethylene units is 60% by weight or more of the total oxyalkylene.

Representative compounds represented by the above general formula include C1-
There are compounds obtained by adding ethylene oxide alone or ethylene oxide and propylene oxide and/or butylene oxide to a C1 to C4 monoalcohol. At that time, the total molecular weight of the polyoxyethylene part, that is, the oxyethylene unit, is 150
0 to 15,000, preferably 2,000 to 10,000,
More preferably, the range is from 3000 to 8000, and the polyoxyethylene moiety, that is, the ratio of total oxyethylene units to total oxyalkylene units is 60% by weight or more, preferably 70% by weight or more, more preferably 7
Ethylene oxide alone, or ethylene oxide and propylene oxide and/or
Alternatively, a polyoxyalkylene compound (a) in which one terminal group is a C1-28 alkyl group and the other terminal group is a hydroxyl group can be obtained by block polymerizing or random polymerizing butylene oxide.

Examples of the organic isocyanate compound (b) include monoisocyanate compounds such as methyl isocyanate, ethyl isocyanate, and phenyl isocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate,
organic diisocyanate compounds such as lysine diisocyanate, phenylene diisocyanate, tetramethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclohexylene diisocyanate;
and their isomers, dimers, trimers, and prepolymers having an incyanate group at the end obtained by reacting with an active hydrogen-containing compound reactive with an isocyanate group in a substoichiometric amount. and so on. Organic diisocyanate compounds are preferably used from the viewpoint of cost and reactivity.

Active hydrogen-containing compound reactive with the isocyanate group [
Examples of C] include water, hydroxyl group-containing compounds, amino group-containing compounds, carboxyl group-containing compounds, and the like. The active hydrogen-containing compound [C] reactive with this incyanate group is not particularly limited, but it is preferably one that does not impair the hydrophilicity of the resulting urethane compound, and usually has a molecular weight of 1000 or less, preferably 500 or less, and 10% by weight. %
Those that produce the above water-miscible compounds are used. Examples of preferred active hydrogen-containing compounds (c) reactive with such isocyanate groups include monoalcohols such as methyl alcohol, propyl alcohol, and butyl alcohol, ethylene glycol, propylene glycol, and 1,4-butanediol. diols, polyhydric alcohols such as trimethylolpropane, pentaerythritol, sorbitol, sucrose, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, various types such as monoethanolamine, jetanolamine, and triethanolamine. Amino alcohols, ammonia, monoamines such as methylamine, propylamine, butylamine, diamines such as drazine, ethylenediamine, piperazine, propylene diamine, isophorodiamine, acetic acid, propionic acid, oxalic acid, maleic acid, fumaric acid. .

Known and commonly used active hydrogen-containing compounds typified by various carboxylic acids such as adipic acid, dimethylolpropionic acid, and lactic acid can be used.

The hydrophilic urethane compound [D] of the present invention comprises (a) a polyoxyalkylene compound represented by the general formula no -(x)m -(Y)n-R, (b) an organic isocyanate compound, and [C ] An active hydrogen-containing compound reactive with an isocyanate group can be synthesized in an organic solvent solution or without a solvent by a known method for synthesizing urethane compounds.

For example, you can react (a) with (b) and then add (c), or you can add (, ) and (c) in advance and then add (b) therein. In (b), (a
) and [C] may be added dropwise separately or in a mixed manner to synthesize a desired urethane compound.

When producing the hydrophilic urethane compound [D] of the present invention, the proportions of compounds (a), m, (b) and (c) used are as follows:
-〇H group of compound (a), -NGO group of compound (b),
and -H group of the active hydrogen-containing compound reactive with the isocyanate group of compound [C] is -OH/-NGO/-11=1
The reaction is carried out at a ratio of /1 to 470 to 3 (equivalent ratio).

Usually -08/-NGO/-11=1/1-310~2
(Equivalence ratio) range is preferable.

The hydrophilic urethane compound [D] of the present invention is shown below (reaction of (a) with diisocyanate and ammonia) (
Reaction of (a) with diisocyanate and alkylamine)
(Reaction of (a) with diisocyanate and alkanolamine) (Reaction of (a) with diisocyanate) ((a)
(reaction of (a) with diisocyanate and diamine) (reaction of (a) with diisocyanate and alcohol) (reaction of (a) with diisocyanate and diol) (reaction of (a) with diincyanate and diol), etc. Here Z
: Isocyanate residue.

R2: Alkyl group, R1: Alkylene group, in which the hydrogen atoms in the urethane bond, urea bond, and amino bond in the hydrophilic urethane compound [D] in the specific formula react with the aldehyde compound as the [B] component. becomes active hydrogen for ) In the present invention, the hydrophilic urethane compound [D] prepared as described above is combined with the above-mentioned [A] amino compound,
(B) Aldehyde compound and [C] C1-4 partially or completely reacted with C1-4 lower alcohol
The aminoplast is etherified with a lower alcohol, but during the reaction, [A] and [B]
, and [D] per 100 parts of solid content obtained from CD
1 to 30 parts of the cocondensate are cocondensed, and then water is added to the resulting cocondensate to perform phase inversion emulsification to obtain an aqueous aminoplast dispersion.

The amount of hydrophilic urethane compound [D] used is [A].

Aminoplast solid content 1 obtained from [B] and [CD
If it is less than 1 part per 00 parts, the water dispersibility of the aminoplast obtained by co-condensing the hydrophilic urethane compound will be poor, and water dispersion may not be possible, or even if it is possible, it will be extremely unstable, so it is preferable. do not have. In addition, the amount of hydrophilic urethane compound [D] is 100% of the aminoplast solid content.
If the amount is more than 30 parts per part, the water dilutability improvement effect will not be significantly improved even if the amount used is further increased.
This is not preferred because it is not only uneconomical, but also because the crosslinking properties of the aminoplast obtained by co-condensing a hydrophilic urethane compound and the water resistance and chemical resistance of the film are significantly reduced. In the present invention, the preferred amount of the hydrophilic urethane compound [D] used is 2 to 20 parts per 100 parts of the solid content of the aminoplast obtained from [A], [B], and [C].

In order to co-condense the hydrophilic urethane compound of the present invention to produce an aqueous aminoplast dispersion, a conventionally known aminoplast production method can be employed.

That is, [A] an amino group-containing compound and [D] a hydrophilic urethane compound are added to a solution in which a [B] aldehyde compound is added to a [C] Ct~4 lower alcohol.

The condensation reaction and the etherification reaction may be carried out simultaneously by reacting at 40 to 120°C for 20 to 180 minutes under an acidic catalyst.

In addition, [A] is added first to a solution containing the lower alcohol of [C]C, ~, and the aldehyde compound (B), and [D] is added during the condensation and etherification reaction under an acidic catalyst. Also good. On the contrary, lower alcohol of (CTC0~) and (B)
First, add (Dl) to the solution containing the aldehyde compound,
During the condensation and etherification reaction under acidic catalyst, [A
] can also be added. Of course, it is also possible to use water or an organic solvent in the reaction system for purposes such as reducing viscosity and controlling the reaction. In other words, the water composition in the organic solvent is [C]C1~,
Lower alcohol and [B] aldehyde compound are added, and under reflux of water or an organic solvent, CA) and [D] are added.
] can also be condensed, or the aqueous composition can be condensed with [B] in an organic solvent.
It is also possible to dissolve the aldehyde compound, condense [A] and [D], and then add the lower alcohol [C]. When using organic solvents, cost,
From the viewpoint of ease of reaction control and solubility of the obtained aminoplast, aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone and methyl isobutyl ketone, acetic esters such as ethyl acetate and butyl acetate, etc. is preferably used. Also, [A] above.

The condensation reaction between [CB], [C], and [D] is normal.

Although the pH of the system is acidic, if [A] is an amino compound that easily gels, such as melamine or a melamine derivative, the reaction can be carried out by making the pi of the system alkaline. Of course, condensation is carried out under acidic conditions at first, and P
Condensation can also be carried out by making H alkaline.

The aminoplast co-condensed with a hydrophilic urethane compound is checked for viscosity, molecular weight, tolerance with alcohol, hydrocarbon solvent, etc., and the reaction is terminated at a desired point.

The aminoplast obtained by co-condensing the hydrophilic urethane compound prepared as described above is then made into an aqueous dispersion by adding water. As a method for aqueous dispersion, water may be gradually added dropwise to the aminoplast co-condensed with a hydrophilic urethane compound while stirring to effect phase inversion emulsification, or the hydrophilic urethane compound may be co-condensed into well-stirred water. The condensed aminoplast may be gradually dropped. Usually, it is preferable to gradually add water dropwise to an aminoplast obtained by co-condensing a hydrophilic urethane compound with high-speed stirring at a temperature of 60° C. or lower to form a phase inversion emulsification. Of course, in aqueous dispersion, it is also possible to use a method of applying mechanical shearing force using various homomixers, homogenizers, etc., and in this case, it is preferable to obtain a stable water-dilutable aminoplast. Furthermore, a method in which ultrasonic waves are applied during aqueous dispersion is also one of the preferred methods. Furthermore, when aqueous dispersing an aminoplast co-condensed with a hydrophilic urethane compound, it is recommended to use an organic solvent that is easily miscible with water in combination with the aminoplast co-condensed with a hydrophilic urethane compound in advance to ensure stable dilution with water. This is a more preferable method for obtaining aminoplasts. Examples of such solvents include lower alcohols 01 to 4, various ethers such as ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, and propylene glycol monobutyl ether, as well as acetone and methyl ethyl ketone. Ketones such as are used.

Of course, among the lower alcohols of [C″IC, ~4],
Although the presence of the extra lower alcohol of C-4 which does not participate in etherification is also effective, aqueous dispersion can be more preferably carried out by using in combination the above-mentioned organic solvent that is easily miscible with water.

The aqueous aminoplast dispersion obtained by co-condensing the hydrophilic urethane compound obtained as described above can be used as it is, but usually a large amount of remaining unreacted lower alcohol and aminoplast synthesis or aqueous dispersion are used. In order to remove the various organic solvents used in conjunction with the dispersion, it is common to azeotropically remove them together with water by heating and reducing pressure.

The aqueous dispersion aminoplast thus obtained can be diluted to infinity with water, and when used alone it not only provides coatings with excellent hardness and chemical resistance, but also provides water-soluble or water-dispersible coatings. Even when mixed with these resins as a curing agent for aqueous full-kid resins, acrylic resins, or oil-free alkyd resins, it has nearly infinite water dilutability and excellent storage stability. A highly crosslinked coating film with excellent hardness, chemical resistance, especially alkali resistance, water resistance, etc. can be formed.

In addition, the aqueous dispersion of aminoplast according to the present invention can be made by using conventionally used water-soluble aminoplasts such as methyl etherified urea resin and methyl etherified melamine resin, or an emulsifier from Great Wall. It has significantly superior properties compared to aminoplast.

The aqueous dispersion of Amiplast according to the present invention can be applied to wood, paper, fibers, plastics, etc. by any known and commonly used method such as dipping, brushing, spraying, or roll coating.
It can be applied to the surface of various base materials such as ceramics, inorganic cement base materials, iron or non-ferrous metals, and can impart excellent performance.

〔Example〕

Examples will be shown below to explain the present invention in more detail, but the present invention is not limited to these Examples in any way unless it deviates from the technical idea of the present invention.

(Reference example): [D]-1 (Synthesis of hydrophilic urethane compound) HO-(CH3CN, 0)n-CH was placed in a glass reaction vessel equipped with a cooling tube, a thermometer, a nitrogen blowing device, and a stirring device.
500 parts of polyoxyethylene monomethyl ether glycol having an average molecular weight of 6,050 represented by No. 3 were added thereto, followed by 13.9 parts of hexamethylene diisocyanate, and the temperature was raised to 120° C. with stirring in a nitrogen gas stream.

The reaction was carried out at the same temperature for 3 hours, and then cooled to 60°C.

Next, 57 g of 5% aqueous ammonia was added all at once, and the reaction was continued at the same temperature for 1 hour. The obtained 10% aqueous solution of the hydrophilic urethane compound was colorless and transparent, with p)I = 8.0, and I
It was confirmed by R and NMR that it was a urethane compound having the following specific formula.

(Reference examples): [D]-2 to [D]-6 and comparative reference example 1
, 2 [Synthesis of hydrophilic urethane compound] (Reference example) Using the same apparatus as [D]-1, (a) polyalkylene represented by the general formula IO-(x)m-(Y)n-R1 Various hydrophilic urethane compounds were synthesized by changing the types and molar ratios of the compound, (b) the organic isocyanate compound, and (c) the active hydrogen-containing compound reactive with the isocyanate group. The results of the above reference examples and comparative reference examples are shown in Table 1.

(Leaving space below) Example 1 In a glass reaction vessel equipped with a cooling tube, a thermometer, a nitrogen blowing device, and a stirring device, 126 parts of melamine, 10 parts of the hydrophilic urethane compound prepared in Reference Example [D]-1, and i- Add 470 parts of butanol/formaldehyde solution and 270 parts of isobutanol, add 0.25 parts of caustic soda, gradually heat while stirring, and hold at 80°C for 40 minutes, then 10%
Six parts of hydrochloric acid was added and the temperature was raised to 93°C over 30 minutes.

Furthermore, the reaction was continued for 2 hours while refluxing the inbutanol. After the reaction, the temperature of the contents was cooled to 80°C, and the pressure was reduced to 100 degrees Hg to reduce the nonvolatile content to 66.5%.
It was concentrated until At this time, N and V50% in xylene
The viscosity when diluted was x2 to Y (Gardner). Next, ethylene glycol monobutyl ether was added to obtain a resin liquid with a nonvolatile content of 50%. Obtained resin liquid 1
00 parts was collected into a flask equipped with a dropping device and a stirring device, and 100 parts of water was added dropwise over 2 hours while stirring well at 1g0rpm at 40°C, resulting in a milky white, extremely stable aqueous dispersion. I got a body. The resulting aqueous dispersion was again concentrated under reduced pressure to 100 mmHg, yielding an extremely stable aqueous dispersion of butyl etherified melamine resin with a nonvolatile content of 51.5% and a viscosity of 130 cρS.

This aqueous dispersion can be infinitely diluted with water.

No separation was observed even after it was allowed to stand for one month.

Example 2 2124 parts of penziguami, 20 parts of urea, 40 parts of the hydrophilic urethane compound prepared in Reference Example [D]-2, and 47% formalin aqueous solution 2 were added to the reaction apparatus used in Example 1.
The pH was adjusted to 8.0 with 10% Na, Go, and 370 parts of n-butanol was added. 6 This was gradually heated and held at 80°C for 40 minutes, and then 915 parts of H was added with stirring. The temperature was raised to 93°C in 80 minutes.At this time, water was extracted as an azeotrope of n-butanol, and n-butanol was removed.
The reaction was continued for 2 hours while refluxing only butanol.
After the reaction was completed, the temperature of the contents was cooled to 80°C, and then the contents were sucked at 100nw100n and concentrated until the resin content was 64.5%. At this time, the viscosity of the solution diluted to 50% with xylene was Q (Gardner).

Next, 100 parts of the obtained resin liquid was collected into a flask equipped with a dropping device and a stirring device, and 100 parts of water was added dropwise over 2 hours while stirring well at 40° C. and 1 g0rρm, and then passed through a colloid mill. Aqueous dispersion was carried out. A milky white, extremely stable aqueous dispersion was obtained. When this aqueous dispersion was again reduced in pressure to 100 mnHg and concentrated, an extremely stable aqueous dispersion of butyl etherified penzoguaminane urea resin having a non-volatile content of 52.1% and a viscosity of 350 cps was obtained. This aqueous dispersion could be infinitely diluted with water, and no separation was observed even after it was allowed to stand for one month.

Examples 3 to 8, Comparative Examples 1 to 4 Synthesis was carried out under the same conditions as in Example 2, except that the types of raw materials and the amounts used were changed. The results are shown in Table 2.

(Space below) Comparative Example 5 Concentrated solution of isobutyl etherified melamine resin obtained in Comparative Example 1 (non-volatile content 74.6%, N in xylene,
V, Cut L/Viscosity at 50% P (Gardner)) was collected, and then Neugen EA-170
(Polyoxyethylene nonylphenol ether 111
B 17 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was added thereto, and 200 parts of water was added dropwise over 2 hours at 40°C with thorough stirring to obtain a milky white aqueous dispersion. This aqueous dispersion has a high viscosity, with a non-volatile content of 28.5% and a viscosity of 8300c.
ps, and separation was observed when stored at room temperature for one month.

Applied processing examples 1 to 5 Regarding the various amino blasts shown in Table 2.

1.6 A water-soluble oil-free alkyd resin obtained by adding trimellidic anhydride to an oil-free alkyd resin obtained from hexanediol-neopentylglycol-trimethylolpropane/isophthalic acid, and neutralizing the remaining acid groups with triethylamine. A processing test was conducted using it as a base. The composition is base resin/aminoplast = 70/3
0 (weight ratio), and after painting, baking was performed at 140° C. for 30 minutes.

The results are shown in Table 3.

Table 3 Application Example 6 Add 100 parts of the aqueous dispersion of aminoblast prepared in Example 6 diluted with water to a non-volatile content of 10%.
Three parts of a 10% ammonium chloride aqueous solution was added as a catalyst to form a treatment bath, and a Tetoron/cotton = 65/35 blend shirt fabric was impregnated to give a hard finish. For comparison, the water-soluble methoxymethylated melamine resin synthesized in Comparative Example 2 was used. The results are shown in Table 4.

Table 4: Bending resistance measured by East Handrometer [Processing conditions] 2 dips Decorative paper was impregnated with a mixture of 100 parts of benzoguanamine resin aqueous dispersion and 1.2 parts of p-toluenesulfonic acid, and heated at 100°C.
and dried for 15 minutes. The impregnated decorative paper was layered on a 3m/m thick plywood board at a temperature of 135°C and a pressure of 20kg/a! So 15
It was compressed for a minute to create a decorative board. Even when the obtained decorative board was immersed in boiling water for 2 hours, no change was observed, and it was an extremely excellent decorative board with a high degree of gloss.

〔Effect of the invention〕

The present invention provides a method for reacting an amino group-containing compound, an aldehyde compound, and a lower alcohol to produce an aminoplast that is partially or completely etherified with a lower alcohol. The present invention relates to a technology for producing an aqueous aminoplast dispersion characterized by condensation and then adding water to the resulting cocondensate to form an aqueous dispersion, thereby providing a storage-stable aqueous noblast dispersion.

The aqueous aminoplast dispersion of the present invention can be applied to the surfaces of various substrates to exhibit excellent performance.

Claims (1)

[Scope of Claims] 1. [A] one or more amino group-containing compounds selected from the group consisting of urea, melamine, acetoguanamine, benzoguanamine, steroguanamine, or spiroguanamine; [B] formaldehyde; one or more aldehyde compounds selected from the group consisting of paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and glyoxal, and [C]C
When reacting the lower alcohols of C_1_ to_4 to obtain an aminoplast partially or completely etherified with the lower alcohols of C_1_ to_4, the [D] hydrophilic urethane compound is reacted with the above-mentioned [A], [B], Add 1 to 30 parts to 100 parts of the solid content obtained from [C] and co-condensate, then add water to the resulting co-condensation liquid and perform an aqueous dispersion with or without solvent removal. Characteristic method for producing aminoplast aqueous dispersion. The hydrophilic urethane compound [D] is (a): General formula HO-(X)_m-(Y)_n-R_1
A compound represented by [However, R_1 in the formula is C_1_～_
2_0 alkyl group, X and Y may be the same or different, and a combination of an essential oxyethylene unit and any one of the oxyethylene unit, oxypropylene unit, or oxybutylene unit. , m and n indicate the number of repeating units. The essential oxyethylene units have a total molecular weight of 1,500 to 15,000, and account for 60% by weight or more based on the total weight of all oxyalkylenes. ](b): Organic isocyanate compound (c): An active hydrogen-containing compound reactive with an isocyanate group is the -OH group of compound (a), the -NCO group of compound (b), and the -H group of compound (c). -OH/-NCO/-
Claim 1, characterized in that it is obtained by reacting at a ratio of H = 1/1 to 4/0 to 3 (equivalent ratio).
A method for producing an aqueous aminoplast dispersion as described in . 3. A method for producing an aqueous aminoplast dispersion according to claim 1, which comprises using an organic solvent miscible with water when adding water to the aminoplast cocondensation liquid to form an aqueous dispersion. . 4. Production of the aminoplast aqueous dispersion according to claim 1 or 3, characterized in that mechanical shearing force is applied when water is added to the aminoplast cocondensation liquid to form an aqueous dispersion. Law. 5. The method for producing an aqueous aminoplast dispersion according to claim 1 or 3, which comprises applying ultrasonic waves when adding water to the aminoplast cocondensation liquid for aqueous dispersion. 6. The method for producing an aminoplast aqueous dispersion according to claim 1, wherein the amino group-containing compound [A] is one or a mixture of urea, melamine, and benzoguanamine. 7. The method for producing an aqueous aminoplast dispersion according to claim 1, wherein the aldehyde compound [B] is one or a mixture of formaldehyde, paraformaldehyde, and glyoxal. 8. The method for producing an aqueous aminoplast dispersion according to claim 1, wherein the lower alcohol [C] is n-butanol, isobutanol, or isopropanol.