JP3008508B2 - Thermosetting resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel and useful thermosetting resin composition. More specifically, the present invention provides, as an essential component, 2-oxo-1,3-dioxolane-
A vinyl copolymer having a specific group of 4-yl group,
An extremely useful thermosetting resin which comprises a specific curing catalyst and a specific curing agent capable of reacting with a hydroxyl group and which has excellent storage stability and provides a cured product having excellent acid resistance and weather resistance. Composition.

[0002] Such a thermosetting resin composition of the present invention is used for a wide range of applications such as coatings, adhesives and sealing agents.

[0003]

2. Description of the Related Art In recent years, there has been a movement, mainly in the automobile industry, to attach importance to the appearance of a coating film. In particular, not only the appearance after painting and baking, but also deterioration due to exposure, especially due to acid rain. For the problem of maintaining the appearance of the coating film, such as deterioration of the appearance, as long as the current aluminum plast-based curing agent and the paint that is a combination of acrylic polyol can no longer satisfy such required performance It is coming.

[0004] In such movements, combinations of polyol type resins with isocyanate prepolymers, combinations of silanol group-containing resins and epoxy group-containing resins, moisture curing with trialkoxysilyl groups, and hydroxyl group-containing resins have been studied. Various paints such as a curing system based on a combination of a resin and an acid anhydride group-containing resin have been gradually developed and studied.

However, among these paint systems, the polyol type resin / isocyanate prepolymer system has a short pot life and has a major drawback in terms of workability.

Further, in a curing system of a silanol group-containing resin and an epoxy group-containing resin, or in a moisture curing system of a trialkoxysilyl group, there is a difference in curability depending on coating conditions, baking conditions, and the like. Is also unsatisfactory.

[0007] In addition, these systems have
Often, there is the disadvantage that the coating film is scratched and the appearance of the coating film is significantly deteriorated.

[0008]

Further, in addition to such long-term storage stability and appearance of the coating film, it is possible to obtain a coating film which can withstand acid rain mainly in the automobile industry. The current situation is that the urgent development of an extremely useful curing system has been strongly demanded.

The inventors of the present invention have sought to eliminate or solve the various drawbacks or problems in the prior art as described above, and have also intensively started research in order to meet the above-mentioned demands.

Accordingly, an object of the present invention is to provide a one-pack type thermosetting resin composition having excellent storage stability, and also having excellent appearance such as acid resistance, weather resistance and smoothness. An object of the present invention is to provide a thermosetting resin composition which is extremely useful.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies with the aim of solving the problems to be solved by the invention as described above, and as a result, have found that 2-oxo-1,3-dioxolan-4. A resin composition in which a curing agent that reacts with a hydroxyl group in the vinyl copolymer is blended with a vinyl copolymer having an yl group, and further a curing catalyst is blended. Completed the present invention by finding that it is possible to give a cured product with improved acid resistance, weather resistance, and excellent coating appearance while maintaining the excellent scratch resistance characteristics of the cured system It came to let.

That is, the present invention provides, as an essential component, at least two general formulas per molecule.

[0013]

Embedded image

(Wherein R ₁ , R ₂ and R ₃
Represents a hydrogen atom or a lower alkyl group having 4 or less carbon atoms, which may be the same or different. 2-oxo-1,3-dioxolane-)
An object of the present invention is to provide a thermosetting resin composition comprising a vinyl copolymer having a 4-yl group (A), a quaternary ammonium compound (B), and a curing agent (C) that reacts with a hydroxyl group. Is what you do.

That is, the thermosetting resin composition of the present invention comprises:
2-oxo-1 in such a vinyl copolymer (A),
A 3-dioxolan-4-yl group (hereinafter, also referred to as a cyclocarbonate group) is converted to 90 to 90 in the presence of a specific catalyst.
Decomposes with decarbonation at a temperature of 140 ° C. and reacts with a curing agent that reacts with hydroxyl groups, such as melamine resin, thereby forming a strong coating film. Resin is an essential film-forming component, and further comprises a specific catalyst such as a curing catalyst as an essential component, and is particularly excellent in storage stability and also excellent in acid resistance. It is intended to provide a very useful one-pack type paint.

Here, the vinyl copolymer having at least two 2-oxo-1,3-dioxolan-4-yl groups in the molecule includes, for example, one polymerizable polymer in the molecule. It may be obtained by copolymerization of a compound having both a saturated double bond and at least one cyclocarbonate group with another polymerizable unsaturated monomer, or may be obtained by a hydroxyl group-containing vinyl polymer. After adding an isocyanate compound such as hexamethylene diisocyanate, and then adding a carbonate monoalcohol such as glyceryl carbonate,

Further, a polymer obtained by adding a carbonate monoalcohol as described above to an isocyanate group-containing polymer such as an isocyanate ethyl methacrylate copolymer may be used.

Further, it may be obtained by adding a carbonate monoalcohol as described above to an acid chloride group-containing polymer, but in particular, one polymerizable unsaturated dicarboxylic acid per molecule may be used. A compound having both a heavy bond and at least one cyclocarbonate group,
Copolymerization of an oxo-1,3-dioxolan-4-yl group-containing polymerizable unsaturated monomer with a compound having one polymerizable unsaturated double bond in one molecule is more preferred. ,
Simple and recommended.

Particularly, a compound used for obtaining the vinyl polymer (A) and having one polymerizable unsaturated double bond and at least one cyclocarbonate group in one molecule is typically used. If only the typical ones are illustrated, the general formula

[0020]

Embedded image

(Where R, R ₁ , R ₂ and R
₃ may be the same or different,
It represents a hydrogen atom or an alkyl group having 4 or less carbon atoms, and n is an integer of 1 to 6. ), A vinyl compound represented by a so-called acrylate monomer.

Specifically, 2,3-carbonatepropyl (meth) acrylate, 2-methyl-2,3-carbonatepropyl (meth) acrylate, 4-methyl-
3,4-carbonate butyl (meth) acrylate, 3
(Meth) acrylates such as -methyl-3,4-carbonate butyl (meth) acrylate, 5-ethyl-5,6-carbonate hexyl (meth) acrylate, 7,8-carbonate octyl (meth) acrylate;
Vinyl compounds such as 2,3-carbonate propyl vinyl ether, methyl-2,3-carbonate propyl malate or methyl 2,3-carbonate propyl crotonate.

The amount of the vinyl compound used is preferably in the range of 1 to 70 parts by weight,
A range of 5 to 45 parts by weight is appropriate. If the amount is less than 1 part by weight, the effect of such a compound cannot be expected. If the amount is more than 70 parts by weight, the remaining cyclocarbonate group hardens and the coating film tends to become brittle. In any case, it is not preferable.

In the molecule, two or more 2
-Oxo-1,3-dioxolan-4-yl group,
In addition, if only a typical carboxyl group-containing unsaturated monomer used for obtaining a vinyl copolymer having at least two carboxyl groups is exemplified, (meth) acrylic acid, Α, β-ethylenically unsaturated mono- or dicarboxylic acids such as maleic acid, fumaric acid or itaconic acid;

A half ester of an α, β-ethylenically unsaturated dibasic acid such as maleic acid, fumaric acid or itaconic acid with a monovalent alcohol having 1 to 4 carbon atoms;
Or a carboxyl group-containing unsaturated monomer obtained by adding a hydroxyl group-containing vinyl monomer such as 2-hydroxyethyl (meth) acrylate and an acid anhydride such as phthalic anhydride.

Further, two or more 2-oxo-1,3-
Having a dioxolan-4-yl group and at least 2
As an acid anhydride group-containing unsaturated monomer used for obtaining a vinyl copolymer also having one acid anhydride group, if it is only a typical example, maleic anhydride or itaconic anhydride may be used. May be copolymerizable, or may be an acid anhydride group-containing unsaturated monomer obtained by de-alcoholing a polycarboxylic acid monoester group-containing unsaturated monomer.

2-oxo-1,3-dioxolan-4-
As other vinyl monomers copolymerizable with the unsaturated monomer having an yl group, alkyl (meth) acrylates having an alkyl group having 1 to 22 carbon atoms can be mentioned, if only typical ones are mentioned. Various (meth) acrylates containing no reactive polar group, such as, 2-ethoxyethyl (meth) acrylate or cyclohexyl (meth) acrylate;

Styrene, tertiary butyl styrene,
aromatic vinyl monomers such as α-methylstyrene or vinyltoluene; (meth) acrylamide or N-
Various (meth) acrylamides such as alkoxymethylated (meth) acrylamide; or fluorinated vinyl monomers such as tetrafluoroethylene or hexafluoropropylene, as well as (meth) acrylonitrile, vinyl acetate or phosphoric acid group-containing (meth ) Acryle
And others.

In order to prepare the vinyl copolymer (A) using various monomers as described above, any known and common polymerization method such as a solution polymerization method or a non-aqueous dispersion polymerization method can be used. Although it is applicable, the solution radical polymerization method is the simplest.

Examples of the solvents used herein are particularly typical ones, and hydrocarbon solvents such as toluene, xylene, cyclohexane, n-hexane or octane; methyl acetate, n-butyl acetate or Ester solvents such as amyl acetate; or ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone or cyclohexanone, and these may be used alone or in combination of two or more.

If only typical radical polymerization initiators are mentioned, azo compounds represented by azobisisobutyronitrile or peroxide compounds represented by benzoyl peroxide are exemplified. It is a publicly known one.

Further, if necessary, lauryl mercaptan, octyl mercaptan, 2
-Mercaptoethanol, octyl thioglycolate,
Various known and common chain transfer agents such as 3-mercaptopropionic acid or α-methylstyrene dimer can also be used.

The vinyl copolymer (A) thus obtained has a number average molecular weight of 800 to 50,000.
A range within is appropriate. If it is less than 800,
Inevitably, it is difficult to obtain a product having the required performance. On the other hand, if it exceeds 50,000, it will inevitably adversely affect workability and the like, and in any case, it is not preferable.

Next, as typical quaternary ammonium compounds (B) used in the present invention, only typical ones will be exemplified. Tetramethylammonium fluoride, tetramethylammonium bromide, trimethylbenzylammonium hydroxide , 2-hydroxypyridine, trimethylammonium methoxide,
Phenyltrimethylammonium chloride, phenyltrimethylammonium bromide, phenyltrimethylammonium hydroxide, phenyltrimethylammonium iodide, phenyltrimethylammonium bromide, phosphocholine chloride sodium salt, stearylammonium bromide, tetra-n-
Butylammonium hydroxide, tetra-n-butylammonium phosphate, tetra-n-dodecylammonium trichloride, tetraethylammonium hydroxide, tetraethylammonium tetrafluoroborate, acetylcholine bromide, alkyldimethylbenzylammonium chloride, benzyl 4 such as choline bromide, benzyl-n-butylammonium bromide, betaine, butyryl chloride, bis (tetra-n-butylammonium) dichromate or trimethylvinylammonium bromide
There are secondary ammonium salts.

[0035]

[0036]

The amount of the quaternary ammonium compound (B) used is suitably in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the solid content of the vinyl copolymer (A). And more preferably in the range of 0.1 to 5 parts by weight.

The amount used is such that when the above-mentioned vinyl copolymer resin forms a coating film, it acts as a large factor on the baking temperature. In particular, when the amount is less than 0.01 part by weight, In any case, the crosslinking reaction does not easily proceed sufficiently, while if it exceeds 10 parts by weight, the storage stability of the thermosetting resin composition and the water resistance of the coating film are significantly reduced. Therefore, either case is not preferable.

Next, as the curing agent (C) which reacts with the above-mentioned hydroxyl group, amino resin, polycarboxylic anhydride,
Known curing agents such as polyisocyanates and blocked isocyanates can be used.

The above-mentioned amino resin is a generic term for urea resin, melamine resin, benzoguanamine resin and the like. More specifically, urea, melamine,
It is obtained by subjecting formaldehyde and an aliphatic alcohol to addition condensation with a benzoguanamine compound as a main component.

As the aliphatic alcohol used for the etherification at that time, methanol, ethanol, isopropanol, isobutanol, n-butanol or the like is used alone or as a mixture.

The polycarboxylic anhydrides described above include
Trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, hetic anhydride, hymic anhydride, maleic anhydride, itaconic anhydride, glycerol anhydride tris (trimellitate), ethylene glycol di (trimellitate) anhydride And the like are particularly representative.

Among the above-mentioned polyisocyanates, particularly typical ones are aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane diisocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexane diisocyanate; isophorone diisocyanate; Alicyclic diisocyanates such as methylcyclohexane-2,4 (or 2,6) -diisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), and 1,3- (isocyanatomethyl) cyclohexane;

The above-mentioned various polyisocyanates and various polyether polyols such as ethylene glycol or polyethylene glycol, polypropylene glycol or polycaprolactone polyol, or
Polyhydric alcohols such as trimethylolethane or trimethylolpropane, low-molecular-weight polyester resins (including oil-modified types) having a functional group that reacts with isocyanate groups, and hydroxyl-containing acrylic copolymers (acrylic polyols) Various adducts with;

An isocyanate compound having a burette structure; or a molar addition product of 2-hydroxypropyl (meth) acrylate to hexamethylene diisocyanate, or copolymerizable with various isocyanate group-containing monomers such as isocyanate ethyl methacrylate. A copolymer comprising, as an essential component, a vinyl monomer having an unsaturated group;

C ₂ -C ₈ alkylene, cycloalkylene and aralkylenediisocyanates, as disclosed in JP-A-61-72013, and C ₁₀
A diol -C _40, in the presence of an isocyanurate-forming catalyst, it has an isocyanurate ring obtained by reacting and such soluble becomes polyisocyanate in a non-polar organic solvents.

Further, as the above-mentioned blocked isocyanate, those obtained by blocking various polyisocyanates as described above with an active hydrogen-containing compound are used. Representative examples of the active hydrogen group-containing compound used for the blocking include phenols such as phenol and cresol; alcohols such as methanol, ethanol, propanol and benzyl alcohol; dimethyl malonate and ethyl acetoacetate. Active methylenes such as; or various oximes such as formaldoxime, acetoaldoxime, methylethylketoxime,
-Caprolactam and the like, which are mainly used, but are not particularly limited.

Next, the use ratio of the above-mentioned vinyl copolymer (A) containing a 2-oxo-1,3-dioxolan-4-yl group and the above-mentioned curing agent (C) which reacts with a hydroxyl group is determined as follows. Is a vinyl copolymer (A) as the first component
The proportion of 1 to 100 parts by weight of the curing agent (C) as the third component is appropriate, and preferably the proportion of 5 to 70 parts by weight, is 100 parts by weight.

When the amount of the curing agent (C) exceeds 100 parts by weight of the vinyl copolymer (A) and the ratio of the curing agent (C) is large, the characteristics of the present invention are hardly obtained. . The thermosetting resin composition of the present invention thus obtained can be used as a clear composition as it is, or can be used as a coloring composition by incorporating a pigment.

The composition of the present invention may optionally contain various conventional additives such as a leveling agent, an ultraviolet absorber or a pigment dispersant.

As a coating method for using the thermosetting resin composition of the present invention as a coating material, a known and common method such as brush coating, spray coating or roll coating can be employed. The temperature is 60-25
The temperature ranges from so-called forced drying to bake hardening within a wide range of 0 ° C.

The thermosetting resin composition of the present invention can be used as a top coat for automobiles or for a wide range of applications mainly for various metal materials. Particularly, remarkable effects can be expected in various fields, such as acrylic resin / melamine resin paint systems, which have not yet reached the required levels in terms of acid resistance, weather resistance, and coating appearance. Further, it can be effectively used for applications such as sealing agents and adhesives.

[0053]

Next, the present invention will be described more specifically with reference examples, examples and comparative examples. In the following, all parts and percentages are by weight unless otherwise specified.

Reference Example [Preparation Example of Vinyl Copolymer (A) Having Cyclocarbonate Group in One Molecule] Thermometer
500 parts of xylene and 300 parts of n-butyl acetate were charged into a four-necked flask equipped with a cooling tube, a stirrer, and a nitrogen gas inlet tube, and heated to 120 ° C.
300 parts of 3-carbonate propyl methacrylate,
A mixture consisting of 200 parts of methyl methacrylate, 200 parts of styrene and 300 parts of n-butyl methacrylate, 200 parts of xylene, 10 parts of azobisisobutyronitrile (AIBN) and tert-butyl
A mixture of 20 parts of oxy-2-ethyl-hexanoate was added dropwise at the same temperature over 5 hours, and after completion of the addition, the reaction was continued at the same temperature for 7 hours to continue the reaction. %, A solution of the target resin having a Gar-donor viscosity at 25 ° C. (hereinafter abbreviated as viscosity) of TU and a number average molecular weight of 12,000 was obtained. Hereinafter, this is abbreviated as resin (A-1).

Reference Example 2 (Same as above) 150 parts of 3,4-carbonate butyl acrylate, 150 parts of styrene, 450 parts of isobutyl methacrylate, 150 parts of 2-ethylhexyl methacrylate, 2,3-carbonate as monomers A target resin having a nonvolatile content of 50.6% and a viscosity of Z in the same manner as in Reference Example 1 except that a mixture consisting of 50 parts of propyl acrylate and 50 parts of acrylic acid was used. Was obtained. Hereinafter, this is abbreviated as resin (A-2).

Reference Example 3 (same as above) As a monomer mixture, 300 parts of 2,3-carbonate butyl allyl ether, 500 parts of vinyl acetate and "Veoba 9" (Chelium, Netherlands) In the same manner as in Reference Example 1, except that the mixture was changed to use a mixture consisting of 200 parts of a branched aliphatic monocarboxylic acid (vinyl ester of 9).
0.5%, viscosity Q, and number average molecular weight 11,
000 was obtained. Hereinafter, this is abbreviated as resin (A-3).

Examples 1 to 5 "Super Beckamine L-" as a curing agent which reacts with the respective cyclocarbonate group-containing resin solutions, quaternary ammonium compounds and hydroxyl groups obtained in Reference Examples 1 to 3 117-60 "(melamine resin manufactured by Dainippon Ink and Chemicals, Inc.) or" Barnock DN-
950 "(a polyisocyanate resin manufactured by the same company)
The thermosetting resin composition of the present invention was obtained by mixing according to the mixing ratio shown in Table 1.

COMPARATIVE EXAMPLES 1 AND 2 The use of the solution of the cyclocarbonate group-containing resin obtained in Reference Example 1 was the only method using no quaternary ammonium compound and no hydroxyl group-reactive curing agent. And a conventional commercial product “Acrydic 52-748” (an acrylic resin manufactured by Dainippon Ink and Chemicals, Inc.) and “Super Becca” Min L-117-60 "(melamine resin manufactured by Dojo Co., Ltd.) and a control acrylic resin / melamine resin-based paint in the form of a compounding ratio of 70/30 (solid content weight ratio) (Comparative Example 2) ) Was prepared.

In each of the above Examples and Comparative Examples,
Each of the thermosetting resin compositions was used as a specimen, and a test plate having a film thickness of 40 to 50 microns was prepared according to the following procedure. Then, for each item shown in Table 1, The coating film performance was evaluated. The results are summarized in the same table.

Material: Bonderite treated (# 144) steel sheet Coating method: Air spray coating Baking conditions: 150 degrees / 20 minutes The test methods and judgment methods for various performances are as described below. .

Appearance of coating film: Visual judgment. Hardness: Using pencil hardness "Mitsubishi Uni" (Mitsubishi Pencil Co., Ltd.) Eriksen: Displayed in (mm) using an Erichsen tester Xylene rubbing: Using a rubbing tester A load of 1 kg is applied to the felt soaked with xylene, and the appearance of the coating film after rubbing 10 times is visually determined. Scratch resistance: Using a rubbing tester, 2 kg of the felt soaked with a 5% aqueous cleanser solution is used. Apply a load and visually determine the appearance of the coating film after 50 rubbings Chemical resistance Acid resistance: Drop a 40% sulfuric acid aqueous solution on the coating film and dry at 70 ° C for 1 hour. And alkalinity resistance: 5%
After being immersed in an aqueous sodium hydroxide solution for 24 hours, it was washed with water, and the appearance of the coating film was visually determined. Weather resistance: One of the two types of gloss retention after irradiation for 2,000 hours using a QUV tester. Gel fraction …………… The coating film remaining rate after immersion in acetone for 24 hours is indicated by weight%.

The quaternary ammonium compounds listed in the table have the following compound names, respectively. Compound-1 ... Trimethylbenzyl ammonium hydroxide Compound-2 ... Tetrabutylammonium fluoride Compound-3 ... Triethylammonium chloride

[0063]

[Table 1] Table 1 (1)

[0064]

[Table 2] Table 1 (2)

[0065]

The thermosetting resin composition of the present invention is excellent in acid resistance, weather resistance, abrasion resistance, coating appearance and storage stability, especially smoothness.

Therefore, it can be said that the thermosetting resin composition of the present invention opens up a new field as a baking paint resin.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 1/00-101/14 C08K 3/00-13/08

Claims (5)

(57) [Claims] (1) at least two general formulas in one molecule: (Wherein R ₁ , R ₂ and R ₃ are each
It represents a hydrogen atom or a lower alkyl group having 4 or less carbon atoms, which may be the same or different. A) a vinyl copolymer having a 2-oxo-1,3-dioxolan-4-yl group represented by the formula (A):
Thermosetting resin composition characterized in that it contains a product (B) and a curing agent (C) that reacts with a hydroxyl group. 2. At least two general formulas in one molecule described above: (Wherein R ₁ , R ₂ and R ₃ are each
It represents a hydrogen atom or a lower alkyl group having 4 or less carbon atoms, which may be the same or different. The vinyl copolymer (A) having a 2-oxo-1,3-dioxolan-4-yl group represented by the formula (A) has a carboxyl group and / or an acid anhydride group in the molecule. 2. The thermosetting resin composition according to 1. 3. A compound having at least two general formulas per molecule (Wherein R ₁ , R ₂ and R ₃ are each
It represents a hydrogen atom or a lower alkyl group having 4 or less carbon atoms, which may be the same or different. The thermosetting resin according to claim 1 or 2, wherein the vinyl-based copolymer (A) having a 2-oxo-1,3-dioxolan-4-yl group represented by the formula (1) is an acrylic copolymer. Composition. 4. A compound having at least two general formulas per molecule (Wherein R ₁ , R ₂ and R ₃ are each
It represents a hydrogen atom or a lower alkyl group having 4 or less carbon atoms, which may be the same or different. ) Vinyl copolymer having a 2-oxo-1,3-dioxolan-4-yl group represented by is a fluoroolefin copolymer, according to claim 1 or thermosetting resin composition according to 2 . 5. A curing agent (C) which reacts with the above-mentioned hydroxyl group.
Is a compound selected from the group consisting of an amino resin, a polyisocyanate compound, and a blocked isocyanate compound, and the thermosetting resin composition according to any one of claims 1 to 4 .