JPH06192532A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition excellent in curability and flexibility, etc., useful for coating operations, by incorporating (A) a specific acrylic resin containing in one molecule an active amino group with (B) a curing agent. CONSTITUTION:The composition can be obtained by incorporating (A) an acrylic resin prepared from (1) pref. 0.1-30wt.% of N-vinylformamide and (2) another polymerizable vinyl monomer [e.g. methyl (meth)acrylate, ethyl (meth)acrylate] with (B) a curing agent (e.g. melamine-formaldehyde resin).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermosetting resin composition capable of forming a coating film having excellent physical properties such as curability, flexibility and acid resistance, and is particularly useful as a resin for paints. .

[0002]

2. Description of the Related Art Heretofore, as a thermosetting resin composition, an acrylic resin having a hydroxyl group as a functional group and a melamine-formamide resin have been representatively used as a crosslinking agent, and other epoxy resins have been used as a crosslinking agent. And those using a blocked isocyanate group-containing resin as a crosslinking agent are known. Also known is a resin containing a carboxyl group-containing acrylic resin and an epoxy resin as a crosslinking agent.

However, according to the above technique, when an acrylic resin having a hydroxyl group as a functional group and a melamine-formaldehyde resin are combined as a cross-linking agent and heat-cured, hardness and corrosion resistance and physical properties thereof are changed due to changes in baking conditions. There is a problem that flexibility is likely to be impaired due to large shake and selective self-condensation of melamine-formamide resin. It is known that when a melamine-formaldehyde resin is used as a curing agent, the basic property of the melamine-formaldehyde resin is that it is easily decomposed by an acid catalyst and therefore the acid resistance is poor. Further, when a blocked isocyanate is used, there is a problem that the dissociation temperature of the blocking agent is high and the baking temperature is limited.

[0004]

As described above, as long as the conventional technique is followed, there are problems such as reactivity between the main resin and the curing agent, curability, etc., which affect the coating film performance.

In the present invention, an acrylic resin having an active amino group is used in place of the hydroxyl group-containing acrylic resin to improve the reactivity with a curing agent and to improve the curability of the coating film. Flexibility without touch
It is to provide a thermosetting acrylic resin composition having excellent acid resistance.

[0006]

Therefore, the present inventor has focused on the problems to be solved by the invention as described above and has made earnest studies. As a result, the above-mentioned various problems in the prior art have been solved. Then, the present invention has been completed.

That is, the present invention provides a molecule obtained by hydrolyzing and / or alcohololytically decomposing an acrylic resin obtained by copolymerizing N-vinylformamide with another polymerizable vinyl monomer. A thermosetting acrylic resin composition containing an active amino group-containing acrylic resin and a curing agent therein, and relates to a thermosetting acrylic resin composition having extremely wide burn width, flexibility, and excellent acid resistance. .

Used in the practice of the present invention,
The acrylic resin solution in which N-vinylformamide is copolymerized can be obtained by copolymerizing N-vinylformamide with another polymerizable vinyl monomer that copolymerizes with N-vinylformamide.

Other polymerizable vinyl monomers include (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and lauryl (meth) acrylate. Acrylic esters;
Hydroxyalkyl monomers such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; α- or β-unsaturated amides such as acrylamide, methacrylamide, and n-methylacrylamide; acrylonitrile and methacrylonitrile. α
-Or β-unsaturated nitriles; styrene derivatives such as styrene, α-methylstyrene, vinyltoluene;
Examples thereof include vinyl esters such as vinyl acetate and vinyl propionate; vinyl halides such as vinyl chloride, vinylidene chloride, and other fluorine-containing monomers; and conjugated dienes such as butadiene. More than one seed is used.

The content of the N-vinylformamide group in the thus-obtained formamide group-containing acrylic resin solution must be within the range of 0.1 to 30 parts based on the solid content of the acrylic resin.

Then, the formamide group-containing acrylic resin solution thus obtained is hydrolyzed and / or subjected to alcoholysis to convert the formamide group into an amino group.

The decomposition reaction of the formamide group proceeds under both an acid catalyst and an alkali catalyst. Acids include hydrochloric acid, sulfuric acid,
Inorganic acids such as nitric acid and phosphoric acid, and organic acids such as paratoluene sulfonic acid and methane sulfonic acid can be used, and as the alkali, caustic soda, inorganic alkali such as caustic potash, trialkylamine, trialkylalkanolamine, Trialkanolamine, triethylenediamine (DABCO), 1,8-diazabicyclo (5,4,0)
An organic alkaline substance such as undecene (DBU) can be used. When the formamide group is decomposed into the amino group, the catalyst-containing formamide group-containing acrylic resin is heated to 60 to 150 ° C. and then is performed in water or an organic solvent. As the organic solvent, a lower alcohol having a relatively low boiling point is preferably used. The progress of hydrolysis can be checked by measuring the amine value in the resin.

The polymerization initiator used in producing the acrylic resin copolymerized with N-vinylformamide in the present invention includes, for example, inorganic persulfates such as potassium or ammonium persulfate, hydrogen peroxide and percarbonate. Oxide compound, ketone peroxide (for example, methyl ethyl ketone peroxide), peroxyketol (for example, 1,1 bis (tachary butyl peroxy) 3,3,5 trimethylcyclohexanone), hydroperoxide (for example, tallow butyl peroxide), Diacyl peroxide (for example, benzoyl peroxide), dialkyl peroxide (for example, tert-butyl peroxide), peroxydicarbonate (for example, dioxypropyl peroxydicarbonate), peroxy ester (for example, tasari) Organic peroxide compounds such as butyl peroxy 2-ethylhexanoate), azobisisobutyronitrile based compound. The amount of the polymerization initiator used is 0.1 to 10% by weight, more preferably 0.5 to 5% by weight, based on the total monomers.

The present invention is a thermosetting resin composition containing an acrylic resin having an active amino group in the molecule obtained by hydrolyzing an acrylic resin copolymerized with N-vinylformamide and a curing agent. . By using a curing agent together, the solvent resistance, chemical resistance and water resistance of the product can be greatly improved.

The curing agent that can be used is not particularly limited as long as it is a compound containing at least one group capable of reacting with an active amino group in the molecule. For example, melamine-formamide resin, epoxy group-containing resin, blocked isocyanate. Examples thereof include group-containing compounds.

The melamine-formamide resin is not particularly limited, but alkyl etherified melamine resins, such as commercially available products, Super Beckamine J-820-60, G-821-60, L-128-.
60, benzoguanamine resin such as Super Beckamine TD-126, urea resin such as Beckamine P-19.
6, P-138 (all manufactured by Dainippon Ink and Chemicals),
Examples thereof include acetoguanamine resin and cyclohexanecarboguanamine resin. The amount of the melamine-formamide resin used is not particularly limited, but is 0.1 to 30% by weight. If it is less than 0.1% by weight, the curability of the coating film will be poor, and if it exceeds 30% by weight, the flexibility of the coating film will decrease, such being undesirable.

The epoxy group-containing resin is not particularly limited, but for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, fatty acid modified epoxy resin or phenol compound modified epoxy resin, monovalent and polyvalent. Examples thereof include functional alcohol mono- and polyfunctional glycidyl ethers and polyfunctional carboxylic acid mono- and polyfunctional glycidyl ethers. As a commercially available product, for example, Epicoat 15 manufactured by Shell Chemical Co., Ltd.
2, 154, 1001, 1002, 1004, 100
7, 1009, 1010, Epicron 1050, 4050, 7050, 70 manufactured by Dainippon Ink and Chemicals, Inc.
55, Denacol EX-11 manufactured by Nagase Kasei Kogyo Co., Ltd.
1, EX-121, EX-141, EX-145, EX
-146, EX-171, EX-192, EX-73
1, monoglycidyl ethers such as EX-147, Denacol EX-211, EX-212, EX-810, 81
1, 850, 861, EX-701, EX-721, E
X-911, 941, 920, 931, 921, 200
0, 4000, EX-922, EX-701, 721 and the like diglycidyl ethers are mentioned, and polyhydric alcohol glycidyl ethers include, for example, glycerin triglycidyl ether, pentaerythritol polyglycidyl ether. Tellurium, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanurate,
Trimethylolpropane triglycidyl ether and the like can be mentioned, and these ready-made epoxy resins can be used as they are. It may be an acrylic resin having a number average molecular weight of 5,000 to 100,000 containing 2% or more of glycidyl (meth) acrylate, or a terminal acid of a polyester resin having an acid value of 10 to 200 and a number average molecular weight of 500 to 20,000. The number of glycidyl functional groups of the epoxy resin is not particularly limited by a method of reacting a polyfunctional glycidyl group with a polyfunctional glycidyl group, but preferably a polyester-modified epoxy resin reacted with a glycidyl compound having two or more glycidyl groups in one molecule. It may be. Further, a modified epoxy resin obtained by reacting a polyfunctional carboxyl compound such as 1,2,3,4 butanetetracarboxylic acid, trimellitic acid, or pyromellitic acid with a glycidyl compound having a polyfunctional glycidyl group may be used. Any of these epoxy group-containing epoxy resins can be used in any proportion within the scope of the claims of the present invention.

The compound containing a block isocyanate group is not particularly limited, but a known blocking agent,
For example, alcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, phenols such as phenol, cresol, nitrophenol, chlorophenol, resorcinol, thiochols such as benzenethiol, caprolactams such as epsiloncaprolactam. , Ethylcarbamate and other carbamates, acetylacetone and other ketoenols, MEK oxime and other ketooximes, and bisulfite sodium and other blocking agents that are already known using isocyanate compounds or prepolymers thereof without catalyst or dibutyl In the presence of a catalyst such as chindylaurylate 30-1
The compound obtained by making it react at 00 degreeC and blocking an isocyanate is mentioned.

The organic solvent usable in the present invention is not particularly limited, but examples thereof include aromatic hydrocarbons such as toluene and xylene, ester solvents such as butyl acetate and ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone and the like. Ketone solvents, alcohols such as n-butanol, isopropanol, ethylene glycol,
Ether solvents such as carbitol and cellosolve, isophorone, ethylene solvents and other organic solvents can be used. These may be used alone or in combination of two or more.

Further, when the acrylic resin of the present invention is reacted with a curing agent, an acid catalyst such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid or the like may be used as a curing aid, if necessary. An acid-blocked amine block or the like can be added.

The thermosetting resin composition of the present invention is used in various fields of application, for example, various coating vehicles, adhesives, pressure-sensitive adhesives,
It can be used as various binders for paper, leather, metal coating, fiber and textile processing and the like.

According to the present invention, by containing an active amino group in the molecule, it is possible to improve the reactivity with a curing agent as compared with a conventional hydroxyl group-containing acrylic resin, and the physical properties change due to changes in baking conditions. , Curability, flexibility,
It is possible to provide a thermosetting resin composition having excellent acid resistance.

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In addition, in the following, “part” is unless otherwise specified.
All are by weight.

Production Example 1 500 parts of isopropyl alcohol (hereinafter referred to as IPA) was charged as a solvent into a flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and an inert gas inlet, and the mixture was put in a nitrogen gas stream. Heat up to 80 ° C. Separately, 115 parts of styrene as a vinyl monomer, 340 parts of ethyl acrylate,
35 parts of N-vinylformamide are weighed and mixed in advance, and 10 parts of azobisisobutyronitrile are weighed in the same manner and injected from separate dropping ports to carry out dropwise polymerization for 4 hours. The obtained resin solution had a nonvolatile content of 53% and a viscosity T-U (hereinafter referred to as resin 1). 20 parts of methanesulfonic acid was added to the obtained resin solution, and the mixture was kept at 60 ° C. for 7 hours for alcoholysis of the formamide group. As a result, from IR analysis and NMR analysis, it was confirmed that about 80% of the N-vinylformamide used was changed to amine.

Production Example 2 500 parts of IPA was charged as a solvent into a flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and an inert gas inlet, and the temperature was raised to 80 ° C. in a nitrogen gas stream. Separately, 120 parts of styrene, 245 parts of ethyl acrylate, 45 parts of butyl acrylate, 15 parts of β-hydroxyethyl acrylate, and 75 parts of N-vinylformamide were separately weighed and mixed as vinyl monomers, and 10 parts of azobisisobutyronitrile was also mixed. The mixture was weighed, injected from separate dropping ports, and polymerized dropwise for 4 hours. The obtained resin solution had a nonvolatile content of 53% and a viscosity T (hereinafter referred to as resin 2). Next, 50 parts of methanesulfonic acid was added, and the mixture was kept at 60 ° C. for 7 hours for alcoholysis of the formamide group.
From IR analysis and NMR analysis, it was confirmed that about 80% of the N-vinylformamide used was changed to amine.

Production Example 3 420 parts of n-butanol was charged as a solvent into a flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and an inert gas inlet, and heated to 120 ° C. in a nitrogen gas stream. . Separately, as a vinyl monomer, 110 parts of styrene, 280 parts of ethyl acrylate, 40 parts of butyl acrylate,
35 parts of β-hydroxyethyl methacrylate and 35 parts of N-vinylformamide were preliminarily weighed and mixed, and 10 parts of perbutyl Z were similarly weighed and injected from separate dropping ports to carry out dropwise polymerization for 4 hours. The obtained resin solution had a nonvolatile content of 55% and a viscosity Z ₄ (hereinafter referred to as resin 3). Next, 80 parts of 1N hydrochloric acid was added and the mixture was kept at 115 ° C. for 5 hours to hydrolyze the formamide group. IR analysis, N
From the MR analysis, the N-vinylformamide used was about 7
It was confirmed that 0% was changed to amine.

Production Example 4 500 parts of IPA was charged as a solvent into a flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and an inert gas inlet, and heated to 80 ° C. in a nitrogen gas stream. Separately, vinyl monomer as styrene 115 parts, ethyl acrylate 3
40 parts of acrylic acid and 5 parts of acrylic acid were weighed and mixed in advance, and 10 parts of azobisisobutyronitrile were weighed in the same manner, injected from separate dropping ports, and polymerized dropwise for 4 hours. The resulting resin solution had a nonvolatile content of 53% and a viscosity of TU (hereinafter referred to as resin 4).

Production Example 5 300 parts of xylene was charged as a solvent into a flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and an inert gas inlet, and heated to 80 ° C. in a nitrogen gas stream. Separately, as vinyl monomer, 110 parts of styrene, 305 parts of ethyl acrylate, 70 parts of β-hydroxyethyl methacrylate
Parts and 15 parts of acrylic acid were weighed and mixed in advance, and 10 parts of azobisisobutyronitrile were weighed in the same manner, injected from separate dropping ports and polymerized dropwise for 4 hours. At the end of the reaction, n-butanol 200 was added. Cut in parts. The obtained resin solution had a nonvolatile content of 50% and a viscosity of U (hereinafter referred to as resin 5).

Test results of the above-synthesized resins and various curing agents are shown in Examples and Comparative Examples in Tables 1 and 2. Examples 1 to 9 and Comparative Examples 1 to 6 Using the acrylic resins obtained in Production Examples 1 to 5, Tables 1 and 2,
Each resin was blended in the formulation (solid content ratio) shown in 3 and diluted to an appropriate viscosity. Prepared resin with a bar coater to a film thickness of 20μ
Was coated on a bondet-treated steel sheet so as to have the same thickness as above, and baked at 140 ° C. for 20 minutes to prepare a coated board, and the physical properties of each coating film were tested.
The results are shown in Tables 1 and 2 together with the composition. Each test method is as follows. <Test Method and Evaluation Criteria> Mitsuzawa: The specular gloss of 60 degrees was measured with a gloss meter.

When the value of the gloss meter is 90 <, ◎, 80 to 9
The case of 0 was evaluated as ◯, the case of 70 to 80 was evaluated as Δ, and the case of 70> was evaluated as x. Primary physical properties: Erichsen after standing for 24 hours after baking was measured by an Erichsen tester. Secondary physical properties: Erichsen after standing for 24 hours after boiling water test (2 hours) was measured by an Erichsen tester.

When the numerical value of the Erichsen tester is 6 <, ◎,
In the case of 4 to 6, the case was ○, in the case of 3 to 4, Δ, and in the case of 3>. Contamination resistance: Magic ink (red, black) 24 hours Good ◎, Good ◯, Bad △
In the case of failure, it was rated as X. Chemical resistance: 5% H ₂ SO ₄ at 20 ° C. for 72 hours ◎ when good, ○ when good, △ when bad
In the case of failure, it was rated as X. Salt spray resistance: 2% after spraying with 5% NaCl at 35 ° C
40-hour strip width 1> ◎, 1-2, ○, 2-5 △, 5 <
In case of x,

[0032]

[Table 1] Note 1) Super Beckamine L-117 Butylated melamine resin manufactured by Dainippon Ink and Chemicals, Inc.

[0033]

[Table 2] Note 1) Super Beckamine L-117 Butylated melamine resin manufactured by Dainippon Ink and Chemicals, Inc. Note 2) Epicron 1050-70 manufactured by Dainippon Ink and Chemicals, Inc. Epichlorohydrin bisphenol A type epoxy resin

[0034]

[Table 3] Note 1) Barnock D-550 manufactured by Dainippon Ink and Chemicals, Inc. Block isocyanate NV55% VISE-G NCO% at the time of dissociation 6.0 to 7.0 Non-yellowing type

[0035]

EFFECTS OF THE INVENTION The thermosetting resin composition of the present invention can form a coating film having excellent curability, flexibility and acid resistance when applied to various bases, coated and cured. It is extremely useful especially for paints.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C09D 139/02 PGL 7921-4J

Claims (3)

[Claims] 1. An active amino group is contained in a molecule obtained by hydrolysis and / or alcoholysis of an acrylic resin obtained by copolymerizing N-vinylformamide with another polymerizable vinyl monomer. A thermosetting resin composition containing an acrylic resin (A) and a curing agent (B). 2. The thermosetting resin composition according to claim 1, wherein the amount of N-vinylformamide is 0.1 to 30% by weight based on the acrylic resin (A). 3. The heat according to claim 1, wherein the curing agent (B) is a compound containing in the molecule at least one or more groups capable of reacting with the active amino group of the acrylic resin (A). Curable resin composition.