JPH111535A - Amino resin alkyl-etherified with isopropyl group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin, having well-balanced properties as a hardening agent for thermosetting resins and suitable for, e.g. coating materials, as a hardening agent for aqueous resins by alkyl-etherification of an amino resin with isopropyl group. SOLUTION: This amino resin is alkyl-etherified with isopropyl group (isopropoxy-etherified amino resin), e.g. shown by formulae I, II, III or IV. It is synthesized from 1 mol. of amino compound (e.g. melamine, urea and benzoguanamine), 1 to 10 mols of formaldehyde and 0.05 to 30 mols of isopropyl alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an alkyl etherified amino resin alkylated with an isopropyl group.

[0002]

2. Description of the Related Art Molecular weights and functional substituents (eg, methylol group, alkyl group, imino group, etc.) are known as factors which greatly affect properties such as reactivity, compatibility and physical properties of amino resins. Among these substituents, an alkyl group derived from an alcohol, which is a general starting material, greatly affects the above properties.

[0003] The alcohol which is a raw material of the alkyl etherification reaction includes methanol, normal butanol (hereinafter abbreviated as n-butanol), isobutanol (hereinafter abbreviated as iso-butanol) and the like industrially.
These are used alone or as a mixture.

When these amino resins having an alkyl substituent are used as a curing agent for thermosetting paints, the main agents (hydroxyl-containing resin polyester polyols, epoxy resins, alkyd resins) at the time of forming a cured coating film due to the substituents , An acrylic polyol, etc.), a difference in the cured form such as self-condensation during thermal curing or a crosslinking reaction with the main agent. Further, the hardness, workability, gloss, weather resistance and the like of the obtained coating film are greatly affected, and these are summarized as shown in Table 1 [Table 1].

[0005]

[Table 1]

On the other hand, in recent years, there has been a growing awareness of preventing air pollution caused by organic solvents emanating from paints and adhesives.
The transition from conventional solvent-based paints to water-based paints is advancing. The conversion to water (water) will be described below with reference to methyl etherified melamine resin, butyl etherified melamine and butyl etherified benzoguanamine resin.

(1) When an amino resin is used as a curing agent in a water-based paint, a methyl etherified melamine resin is frequently used as the curing agent from the viewpoint of water solubility.
US Pat. No. 3,464,94
Nos. 6 and 3,444,114 are disclosed. However, since this curing agent is a methyl etherified melamine resin or its oxycarboxylic acid modified product, the cured coating film was insufficient in boiling water resistance and processability, and a satisfactory coating film could not be obtained.

(2) On the other hand, attempts have been made to make butyl etherified melamine and butyl etherified benzoguanamine resins aqueous. In the case of a butyl etherified amino resin, aqueous conversion is complicated. The following method is disclosed for the aqueous solution. That is, in JP-A-4-108849, a glycol ether compound is indispensable, so that steam sterilization is inferior.In addition, as a production method, an alkyl ether compound is produced, and then a complicated oxycarboxylic acid and a glycol ether compound are co-condensed. It takes two steps.

[0009]

The problem to be solved by the present invention is that when used as a curing agent for a thermosetting resin,
An object of the present invention is to provide an alkyl etherified amino resin capable of easily obtaining a performance balance. Another object is to provide an alkyl etherified amino resin as a curing agent for an aqueous resin that can be suitably used for paints, inks, adhesives, and the like.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies by introducing various substituents into an amino resin. The inventors have found that a resin has the best balance in coating film performance and has an excellent feature that it can be used also as a curing agent for an aqueous resin, and thus completed the present invention. That is, the present invention

[1] An alkyl etherified amino resin alkylated with an isopropyl group,

[2] The alkyl etherified amino resin according to [1], wherein the amino compound comprises melamine, benzoguanamine and / or urea;

[3] It is characterized by being synthesized using melamine, urea and benzoguanamine as raw materials in a total of 1 mol, formaldehyde in 1 to 10 mol and isopropyl alcohol in 0.05 to 30 mol.
Or the alkyl etherified amino resin according to [2],

[4] The alkyl etherified amino resin according to any one of [1] to [3], which can be used as a curing agent for a thermosetting resin or a water-soluble resin,

[5] A resin composition comprising the alkyl etherified amino resin according to any one of [1] to [4] and an acrylic resin, a polyester resin and / or an epoxy resin having a hydroxyl group.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Alkyl etherified amino resin alkylated with an isopropyl group mentioned in the present invention (hereinafter abbreviated as isopropoxy etherified amino resin)
As the type of the functional group, the substituted alkyl chain may be an isopropoxy group, and other functional groups other than the alkyl ether group present in the amino resin, such as imino group, iminomethylol group, and methylol group. It is also used for mixing groups. Here, four of the resins disclosed in the present invention were used.
One is illustrated in FIG. 1 [FIG. 1].

[0017]

FIG. 1: Exemplary compounds

The amino compounds used in the isopropoxyetherified amino resin include melamine, benzoguanamine, urea and the like. These may be used alone or in combination.

Hereinafter, the isopropoxyetherified amino resin of the present invention will be described in more detail. (1) There are various methods for introducing an isopropoxy group into an amino compound.
A method using PA as a raw material is simple.
An amino resin into which IPA and other alcohols are mixed to introduce various kinds of alkyl groups in addition to isopropoxy groups is also suitable for the purpose of the present application. In this case, the molar fraction of IPA is preferably in a range exceeding 50%. When the molar fraction of IPA is less than this, the properties of the resulting isopropoxy-etherified amino resin follow properties derived from alkyl groups other than isopropoxy groups.

In addition, the amino resin etherified with an alkyl group derived from an alcohol other than IPA has a bias in the performance balance. For example, a methyl etherified amino resin is easily water-based, but is inferior in water resistance. When producing an ethyl etherified amino resin using ethanol, it is expensive as a raw material. An amino resin alkyl-etherified with an n-butyl group or an iso-butyl group is excellent in processability and the like, but cannot be converted to an aqueous solution as it is.

On the other hand, in the case of the isopropoxyetherified amino resin, the processability, hardness, water resistance and the like are almost the same as those of the butyletherified amino resin, and are not found in the methyletherified or butyletherified amino resin. It was also found to have stain resistance. Further, regarding the point of aqueous conversion, it can be easily used as it is.

(2) The starting materials used in the synthesis of the isopropoxyetherified amino resin are 1 to 10 mol of formaldehyde and 0.1 to 1 mol of IPA per 1 mol of the amino compound.
The ratio is from 0.5 to 30 mol. When the amount of formaldehyde is less than 1 mol, methylolation and alkyl etherification are insufficient, and when used as a curing agent for baking-type paint, curability and resin solubility are poor. On the other hand, if it exceeds 10 moles, it becomes substantially excessive in the reaction with the amino compound, and must be removed later, which is economically disadvantageous. IP
When A is less than 0.05 mol, the solubility of the obtained resin is inferior, and when it exceeds 30 mol, excess must be removed at the time of production, which is not practical.

(3) As a production method, a predetermined amount of an amino compound, formaldehyde, and IPA are charged, the temperature is increased, and methylolation is performed. Then, an acid catalyst is added, and an alkyl etherification reaction is performed with IPA. Thereafter, the reaction system may be neutralized, and if necessary, dealcoholized to a predetermined concentration under normal pressure or reduced pressure.

(4) The resin composition containing the isopropoxyetherified amino resin can be used as a curing agent for a thermosetting resin. In particular, it can be used as a curing agent for a baking-type paint using a thermosetting resin by mixing with a hydroxyl group-containing acrylic resin, polyester or epoxy resin at an arbitrary ratio. The isopropoxyetherified amino resin has hydrophilicity and can be diluted with water. Therefore, it can also be used as a curing agent for baking type water-based paints.

(5) The isopropoxyetherified amino resin composition of the present invention is useful as a curing agent when it is used for coatings and the like. In this case, examples of the resin serving as the main agent include resins such as an acrylic resin, an epoxy resin, a polyester resin, an alkyd resin, and a polyamide. In terms of the time required for curing and the physical properties of the cured product to be obtained, the ratio of the main agent / curing agent is preferably 40/60 to 90/10 in terms of practical use.

(6) When the thus obtained coating composition is used as a sealer or a base coat coating, a predetermined amount of a metal pigment, a coloring pigment or the like may be blended. In addition, commonly used paint additives such as a flow control agent, a dispersant, a surface control agent, an antifoaming agent, an ultraviolet absorber, an antistatic agent and an antioxidant may be added. Also, when used as a clear coat, blend a small amount of pigment,
It may be colored to such an extent that the masking property is not completely exhibited.

(7) When the isopropoxyetherified amino resin (composition) of the present invention is used as a curing agent for paint, the above components are blended and diluted by a general method to adjust the viscosity. Paint and apply. Subsequently, a coating film is formed by heating. Examples of the coating method include a usual method, for example, bar code coating, brush coating, spray coating, dip coating, and the like.

[0028]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples, Reference Examples, Examples, and Comparative Examples, but the present invention is not limited thereto. In the description, “parts” and “%” are based on weight unless otherwise specified.

Production Example 1 Production of isopropoxyetherified amino resin In a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen inlet tube, 126 parts (1 mol) of melamine,
202.1 parts (6.2 mol) of 92% paraformaldehyde and 1503.0 parts (25 mol) of IPA were charged and heated to the reflux temperature. After performing the methylolation reaction at the reflux temperature for 1 hour, 1 part of paratoluenesulfonic acid was added, and the alkyl etherification reaction was performed under the reflux state for 3 hours.

Thereafter, the mixture was neutralized with a 1 / 10N aqueous sodium hydroxide solution, and IPA was distilled off under reduced pressure to obtain an isopropoxyetherified amino resin (a-1). The obtained resin had a nonvolatile content of 80% and a viscosity of Z ₂ ^+1/3 (Gardner No./
25 ° C). Further, isopropoxyetherified amino resins (a-2) to (a-8) were obtained in the same manner as in Production Example 1 by mixing the raw materials shown in Table 2 [Table 2].

[0031]

[Table 2]

Production Example 2 Production of amino resin mixed and alkyl etherified with IPA and n-butanol 126 parts (1 mol) of melamine were placed in a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen inlet tube.
221.7 parts (6.2 mol) of 92% paraformaldehyde, a mixture of IPA and n-butanol [IPA: n-butanol]
Butanol = 601.0 parts (10 mol): 519.0 parts (7 mol)] and 1 part of triethanolamine, and the mixture was heated to the reflux temperature.

After performing the methylolation reaction at the reflux temperature for 1 hour, 1 part of paratoluenesulfonic acid was added, and the alkylation reaction was performed under reflux for 3 hours. After neutralization by addition of triethanolamine while checking with a pH meter, I
PA and n-butanol were distilled off to obtain an amino resin mixed and alkylated with IPA and n-butanol. The obtained resin had a nonvolatile content of 80% and a viscosity W (Gardner No./25° C.).

A test plate was prepared according to Reference Example 1 in order to evaluate the performance when the isopropoxyetherified amino resin composition was used as a curing agent for a baking type paint.

Reference Example 1 Preparation of Test Plate (Preparation of Paint 1) In order to compare the performance as an amino-based curing agent, the following paints were blended to obtain (a-
Isopropoxyetherified amino resin compositions 1) to (a-9), as comparative examples, methylated melamine resin (trade name, Cymel 303: Mitsui Cytex Co., Ltd.), butylated melamine resin (trade name, Euban 2021) : Mitsui Toatsu Chemical Co., Ltd., nonvolatile content 75%).

As the main ingredient, three kinds of polyester resins [Almatex HMP15 (trade name, nonvolatile content 50%
(Mitsui Toatsu Chemicals), Byron 560 (trade name, Toyobo Co., Ltd.), Byron GK130 (trade name, Toyobo Co., Ltd.)] were used. These polyester resin and amino resin are blended at a solid content ratio of 80:20, and titanium oxide (R
920: trade name, DuPont) / Phthalocyanine blue / Phthalocyanine green 75/15/10 pigment composition, leveling agent resinmix RL-4 [resin solid content 0.4% (Mitsui Toatsu Chemicals)], as a curing catalyst Catalyst 6000 [resin solid content 1.0% (Mitsui Toatsu Chemicals)] was added to make PWC = 28.5%, and a diluting solvent (xylene / n-butanol / propylene glycol monomethyl ether acetate = 2/1). / 2), and kneaded and dispersed using a sand mill to obtain a paint (paint preparation 1).

This paint was applied to a zinc phosphate treated steel plate (150 mm × 70 mm × 0.8 mm thick) coated with a commercially available block urethane-curable epoxy resin type primer by a bar coater so as to have a cured dry film thickness of 15 μm. After painting using
A test plate was obtained by curing and drying at 260 ° C. for 35 seconds, and evaluated by the following method.

Tests and Evaluation Methods (1) Bending Test: The test plate is bent with the coating surface as the outer surface, and the resistance of cracking caused by the difference in elongation between the upper surface and the lower surface of the coating film is examined. The bent portion was peeled off with a cellophane tape (manufactured by Nichiban Co., Ltd.), and the peeling state at that time was visually observed, and a 5-point method was used, with 5 points being a perfect score.

(2) Pencil hardness: The hardness of the coating film on the test plate was evaluated according to the pencil scratch test of JIS-K5400.6.14.

(3) Boiling resistance: After a test in a high-pressure steam sterilizer at 1.5 kg / cm ² and 127 ° C. for 30 minutes, the surface condition of the coating film at that time was visually observed, and a score of 5 out of 5 was given. It was evaluated by the point method.

(4) Bending test after boiling: After treatment with a high-pressure steam sterilizer at 1.5 kg / cm ² and 127 ° C. for 30 minutes,
The test was performed according to the bending test of (1).

(5) Scratch property: An unused coin is pressed at an angle of 45 ° against the surface of the coating film, and a force is applied to pull it toward the user. Visual observation of the state of the scratches remaining on the coating surface at that time,
Scratchability was evaluated by a 5-point scale with 5 points being a perfect score.

(6) Stain resistance test: After drawing a straight line of 4 cm on the painted surface with three red, blue and black magic inks (manufactured by Magic Ink Co., Ltd.), wiping with xylene and visually observing the disappearance of the ink. Evaluation was made by a five-point method.

Next, in order to evaluate the performance when the water-dilutable isopropoxyetherified amino resin composition was used as a curing agent for an aqueous baking type paint, a test specimen (test plate) was prepared according to Reference Example 2. did. The results are shown in Tables 3 to 5 [Tables 3 to 5].

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

Reference Example 2 Preparation of Test Plate (Preparation of Paint 2) In order to compare the performance as a curing agent for aqueous resins, (a-1) to (a-9) obtained in Production Examples with the following formulations were prepared. )
Isopropoxyetherified amino resin composition, Cymel 303 (trade name, methylated melamine resin: Mitsui Cytec), aqueous butylated melamine resin (JP-A-8-165408), Almatex W
A911 (trade name, acrylic resin, nonvolatile content 60%: Mitsui Toatsu Chemicals, Inc.) was neutralized by equivalent amount with dimethylethanolamine. (A-1) to (a-9) obtained in Reference Example were blended so as to have a solid content ratio of 70:30 (acrylic resin / amino resin), and diluted with pure water to reduce the paint nonvolatile content to 30 to 30%. 40
% To obtain a paint.

This paint was applied on a tin plate (JIS G 3303) using a bar coater so that the dry film thickness became 10 μm.
Baking was performed at 5 ° C. for 5 minutes to obtain a test plate (paint preparation 2). The coating film properties of this test plate were evaluated by the following methods. Table 6 [Table 6] shows the evaluation results of the coating films.

[0050]

[Table 6]

Discussion of Results Examples and comparative examples will be described. (1) In the case of a test plate (paint preparation 1) using a high-molecular-weight polyester as a main component, the isopropoxy-etherified amino resin composition is used for the bending property indicating the workability of the coating film, the boiling resistance and the bending property after boiling. Has the same performance as Uban 2021, which is the butylated melamine resin described in the comparative example. On the other hand, the pencil hardness indicating the hardness of the coating film has a performance slightly similar to that of methylated melamine. That is, the isopropoxyetherified amino resin composition exhibits a property in which the substituted alkyl group is equivalent to a butyl group with respect to processability and water resistance,
Regarding the performance of the coating film hardness, the performance of the substituted alkyl group is equivalent to that of the methyl group.

This is because, when reacting with the hydroxyl group on the main agent side, the starting IPA is a low-boiling compound and a secondary alcohol.
Since the reaction with the hydroxyl group and the reaction returning to the alkyl ether are equilibrium reactions, the difficulty in returning to the alkyl ether has an advantageous effect on the improvement of the crosslink density of the coating film, and the remaining alkyl group is more hydrophobic than the methyl group. It is considered that this is because it contributes to the improvement of water resistance. This unique crosslinked form is characteristic of the isopropoxyetherified amino resin composition. This is considered to contribute to the excellent stain resistance which is a characteristic of the composition of the present invention.

(2) In the case of the aqueous resin curing agent used in the paint preparation example (paint preparation 2), except for Example 8, which is a urea resin used as a raw material of an amino resin, an aqueous resin having a problem in water resistance The disadvantages are complemented.

[0054]

The isopropoxy-etherified amino resin composition of the present invention can easily obtain a good balance of performance when used as a curing agent for a thermosetting resin, and can be easily used as a curing agent for an aqueous resin. Can be. Further, this water-based resin can be used for applications such as paints, inks, and adhesives.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 101/00 C08L 101/00 C09D 161/32 C09D 161/32

Claims (5)

[Claims] 1. An alkyl etherified amino resin alkyl etherified with an isopropyl group. 2. The alkyl etherified amino resin according to claim 1, wherein the amino compound comprises melamine, benzoguanamine and / or urea. 3. The method according to claim 1, wherein the melamine, urea and benzoguanamine are synthesized as starting materials in a total of 1 mol, formaldehyde in 1 to 10 mol and isopropyl alcohol in 0.05 to 30 mol. The alkyl etherified amino resin as described above. 4. A thermosetting resin or a water-soluble resin which can be used as a curing agent.
4. The alkyl etherified amino resin according to any one of claims 1 to 3. 5. A resin composition comprising the alkyl etherified amino resin according to claim 1 and an acrylic resin, a polyester resin and / or an epoxy resin having a hydroxyl group.