JPH0412891B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a curable composition. More specifically, it has good stability and is useful for applications such as paints, inks, and adhesives that cure at low temperatures to provide coatings with excellent drying properties, hardness, weather resistance, solvent resistance, adhesion, etc. The present invention relates to a curable composition. (Prior art and problems to be solved by the invention) Conventionally, in fields where heat treatment is not suitable, such as plastics, concrete, building materials, and automobile repair,
Room-temperature-drying acrylic lacquers containing nitrocellulose, cellulose acetate butyrate, etc., and room-temperature-curing two-component urethane resin paints are widely used. The former acrylic lacquer is characterized by its low cost and ease of use, and the latter two-component urethane resin paint has excellent coating film performance due to the crosslinking reaction between polyol and polyisocyanate compound. It has the following drawbacks. In other words, in order to obtain the desired performance of acrylic lacquer, it is necessary to increase the molecular weight of the polymer and raise the glass transition temperature (Tg℃), but for this purpose it is necessary to dilute it with a large amount of organic solvent. shall be. This is not compatible with the recent demand for high solids paints from the viewpoint of resource conservation and environmental pollution. Furthermore, two-component urethane resin paints have the disadvantage that the pot life of the paint itself is short, and there are also problems in terms of toxicity and cost due to the polyisocyanate compound used. Although various research and development efforts have been made to develop new curing systems to solve these problems,
The current situation is that a paint with performance that can replace conventional technology has not yet been obtained. (Means and effects for solving the problems) As a result of extensive research, the present inventors found that a polymer containing a specific functional group and a compound containing at least two epoxy groups in the molecule are essential. It has been found that the composition contained as a component does not have any of the above-mentioned problems, has excellent stability of the composition and the coating material using the same, and can be extremely easily cured at room temperature after being applied. Furthermore, it was discovered that the composition can form a coating film with excellent drying properties, hardness, weather resistance, solvent resistance, and adhesion, leading to the completion of the present invention. That is, the present invention comprises 1 to 20% by weight of a carboxyl group-containing polymerizable unsaturated monomer (a) and 80 to 99% by weight of other polymerizable unsaturated monomers (b) (however, (a)+ (b)
is 100% by weight. ) is first reacted with an alkyleneimine (c) and then with a ketone (d) to obtain a polymer () containing a ketimine group and at least two epoxy groups in the molecule. The present invention relates to a curable composition containing a compound (2) (hereinafter referred to as an epoxy compound (2)) as an essential component. In the present invention, examples of the carboxyl group-containing polymerizable unsaturated monomer (a) used for producing the ketimine group-containing polymer (a) include (meth)acrylic acid, cinnamic acid, and crotonic acid. unsaturated monocarboxylic acids; examples include unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid or their monoesters, and one type or a mixture of two or more types selected from these groups is used. I can do things. The monomer (a) serves as a reactive group when reacting with the alkylene imine (c), and is used in an amount of 1 to 20% by weight. Usage amount is 1
If it is less than 20% by weight, it cannot be a substantially effective amount in the reaction with alkyleneimine (c), and on the contrary, if it is less than 20% by weight
If it is used in an amount exceeding 100%, the water resistance and stability of the curable composition will deteriorate, which is undesirable. Other polymerizable unsaturated monomers (b) used in the production of the ketimine group-containing polymer (2) are not particularly limited as long as they can be copolymerized with the monomer (a), such as methyl, (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate,
Isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, (meth)acrylonitrile, styrene,
α-methylstyrene, vinyl acetate, vinyl propionate, (meth)acrolein, dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate, (meth)acrylamide, N-methylol (meth)acrylamide, 2-hydroxyethyl ( Examples include meth)acrylate and 2-hydroxypropyl(meth)acrylate, and one type or a mixture of two or more types selected from these groups can be used. Other polymerizable monomers (b) are used in a range of 80 to 99% by weight, but among the monomers (b), molecules such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate A polymerizable unsaturated monomer containing a basic nitrogen atom is preferably used because it has the effect of promoting the crosslinking reaction between the functionality contained in the monomer (a) and the epoxy compound (). , the amount used can be 0.5 to 10% by weight. The polymer, which is a precursor for obtaining the ketimine group-containing polymer (), can be obtained by copolymerizing the above monomers (a) and (b) according to a known procedure. For example, a polymerization method such as a solution polymerization method, a bulk polymerization method, or a suspension polymerization method can be employed, but in the present invention, it is preferable to manufacture by a solution polymerization method. When the polymer is produced by a polymerization method other than solution polymerization, a step of dissolving the polymer in an organic solvent that can dissolve the polymer is required. Solvents that can be used when employing the solution polymerization method include, for example, toluene, xylene, and other high-boiling aromatic solvents; ester solvents such as ethyl acetate, butyl acetate, and cellosolve acetate;
Solvents other than ketone solvents such as alcohol solvents such as methyl alcohol, ethyl alcohol, n-butyl alcohol and isobutyl alcohol can be mentioned, and one type or a mixture of two or more types selected from these groups can be used. I can do it.
Furthermore, usable polymerization initiators include azobisisobutyronitrile, benzoyl peroxide, and di-tert-butyl peroxide. The polymerization temperature ranges from room temperature to 200°C, preferably from 40 to 120°C. A polymer () containing a ketimine group is obtained by first reacting the polymer obtained by the above procedure with an alkylene imine (c) in an amount equivalent to or more than the carboxyl group contained in the polymer to contain a primary amino group. A polymer is obtained by reacting the ketone (d). In this case, examples of the alkylene imine (c) that can be used include ethyleneimine, propylene imine, and butylene imine. In addition, in order to react alkylene imine (c), for example, at room temperature to
The polymer and the alkylene imine (c) may be mixed and stirred at a temperature of 150°C, preferably 50 to 100°C. The reaction when the thus obtained polymer containing a primary amino group is reacted with the ketone (d) to form a polymer () containing a ketimine group can be expressed by the following formula (1). formula Examples of the ketone (d) that can be used include acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, methyl propyl ketone, ethyl isopropyl ketone, cyclohexanone, cyclopentanone, and acetophenone, and one or two of these can be used. You can use more than that. Polymers containing ketimine groups ()
For example, a polymer containing a primary amino group and the above ketone (d) are heated at 60 to 200°C, preferably 80 to 150°C.
It is produced by reacting at a temperature of ℃ while removing water generated during the reaction from the system. In this reaction, the amount of ketone (d) used is preferably 1.0 to 5.0 moles per mole of primary amino groups contained in the polymer. In the present invention, the significance of reacting a polymer containing a primary amino group with a ketone (d) to obtain a polymer () containing a ketimine group is as follows. That is, when a polymer containing a primary amino group is directly used instead of a polymer () containing a ketimine group without reacting with the ketone (d),
When the epoxy compound (2) is blended, the stability is significantly reduced, resulting in a significant thickening phenomenon, and in some cases, complete curing may occur before use. The ketimine group-containing polymer (2) does not have such drawbacks, and moreover, during coating, it reacts very easily with the epoxy compound (2) in the presence of moisture to form a cured film. The epoxy compound () used in the present invention is not particularly limited as long as it has at least two epoxy groups in the molecule, but particularly suitable epoxy compounds () in the present invention include, for example, ethylene glycol diglycidyl ether, Examples include propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, glycerol polyglycidyl ether, sorbitol polyglycidyl ether, and copolymers containing glycidyl (meth)acrylate components. It can be used. The curable composition of the present invention comprises a ketimine group-containing polymer () and an epoxy compound () as essential components. The blending ratio of the ketimine group-containing polymer () and the epoxy compound () is not particularly limited,
It can be used arbitrarily depending on the performance to be imparted, but in consideration of weather resistance, hardness, solvent resistance, etc., it is preferable to use epoxy Compound ()2
~20 parts by weight. The curable composition of the present invention can be used as is for paints, inks, adhesives, etc., but if necessary, known fillers, leveling agents, plasticizers, etc.
Additives such as stabilizers, dyes, pigments, and antistatic agents may be included as appropriate. (Effects of the Invention) The curable composition of the present invention has excellent liquid stability and low-temperature curability, and therefore can be suitably used for various applications such as paints and inks. When the curable composition of the present invention is used for paints, various inorganic and organic pigments can be easily dispersed by a known pigment dispersion method, and it can be used as a colored enamel paint. Paints using the curable composition of the present invention as a vehicle component can be applied by spray painting, roll painting,
Metals, inorganic materials,
It can be applied to plastics, wood products, etc., and forms a film with excellent drying properties, hardness, weather resistance, solvent resistance, and adhesion. In particular, it has excellent low-temperature curability and adhesion to various substrates, so it can be applied to substrates that are not suitable for heat treatment, such as plastics and wood products, and to substrates with poor adhesion, such as chrome plating and stainless steel. Furthermore, by using the curable composition of the present invention, there is no need to worry about short pot life or isocyanate-based toxicity, which is the case with urethane paints, and paints with the above characteristics can be produced easily and at low cost. Because it can be manufactured in a wide variety of ways, it can be used for a wide range of purposes, including large structures, automobile repair, and woodworking such as furniture painting. (Examples) Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited by the following Examples. In addition, unless otherwise specified, parts and % in the examples indicate parts by weight and % by weight, respectively. Reference Example 1 Production of polymer containing Γ ketimine group 50 parts of isopropyl alcohol was charged into a four-necked flask equipped with a stirrer, thermometer, condenser, dropping funnel, and nitrogen gas introduction tube, and the temperature was raised to 80°C. .
While blowing nitrogen gas there, methacrylic acid 3
parts, 1 part of dimethylaminoethyl methacrylate,
A mixture of polymerizable monomers and a polymerization initiator consisting of 20 parts of methyl methacrylate, 22 parts of butyl methacrylate, 4 parts of butyl acrylate, and 0.5 parts of azobisisobutyronitrile was added dropwise from the dropping funnel over a period of 2 hours. After being maintained at .degree. C. for 6 hours, the solution was cooled to room temperature to obtain a solution of a polymer containing carboxyl groups. Then, 3 parts of ethyleneimine were added dropwise to the flask over 10 minutes. One hour after finishing the dropping, the temperature was raised to 75℃, and the temperature was increased to 50℃ at the same temperature.
After holding for a period of time, a distillation device was set in the four-necked flask, heated under reduced pressure, and the isopropyl alcohol was flowed out of the system together with unreacted ethyleneimine while replenishing the same amount of toluene as the flow-out amount, and the remaining Ethyleneimine was completely removed. 10 parts of methyl isobutyl ketone was added to the entire solution of the polymer containing primary amino groups obtained in this way, and the reaction was carried out under heating and reflux while removing water and excess solvent generated during the reaction from the system. Thus, a solution of a polymer containing ketimine groups with a nonvolatile content of 50% (hereinafter referred to as polymer 1 liquid) was obtained. Reference Examples 2 to 3 Production of a polymer containing a ketimine group In Reference Example 1, the composition of the polymerizable monomer, the type and amount of solvent used, the amount of ethyleneimine used, and the type and amount of ketone used were The operations in Reference Example 1 were repeated except as shown in the table to obtain solutions of a polymer containing ketimine groups with a non-volatile content of 50% (hereinafter referred to as polymer 2 liquid and polymer 3 liquid). Ta.

【table】

[Table] Comparative Reference Example 1 Γ Production of a polymer containing a primary amino group The same operation as in Reference Example 1 was repeated except that the reaction with methyl isobutyl ketone was not carried out, and the nonvolatile content was reduced to 50 % of primary amino groups (hereinafter referred to as Comparative Polymer 1 Solution) was obtained. Comparative Reference Example 2 Production of a polymer containing a Γ carboxyl group The same operations as in Reference Example 1 were repeated except that the reaction with ethyleneimine and methyl isobutyl ketone was not performed to remove the nonvolatile components.
A solution of a polymer containing 50% carboxyl groups (hereinafter referred to as comparative polymer 2 solution) was obtained. Examples 1 to 3, Comparative Examples 1 to 2 120 parts of Polymer 1 to 3 liquids and Comparative polymers 1 to 2 liquids obtained in Reference Examples 1 to 3 and Comparative Reference Examples 1 to 2 and titanium oxide (Tipaque R-820 Manufactured by Ishihara Sangyo Co., Ltd.)
Put 40 parts into a sand mill container and grind at 2000 rpm.
After stirring at high speed for 30 minutes, the pigment weight concentration in non-volatile matter was 40.
% polymer liquid pigment dispersion was obtained. To this pigment dispersion, add an epoxy compound (glycerol polyglycidyl ether, manufactured by Nagase Sangyo Co., Ltd.) in the same number of equivalents as the number of equivalents of ketimine groups contained in the polymer in the dispersion.
were blended to obtain paints 1 to 3 and comparative paints 1 to 2, each of which uses curable compositions 1 to 3 and comparative compositions 1 to 2 as binders. These paints were spray applied to a zinc phosphate treated steel plate to a dry film thickness of 40μ, and then heated at 60°C.
After drying for 30 minutes, various test coatings were obtained. The results of various tests on these coatings are shown in Table 2. [Methods for testing the performance of coating films and their evaluation criteria] (1) Drying property: Evaluation was made by touching the film immediately after forced drying. ◎... No change 〇... Slight marks left △... Marks left ×... Strong adhesion (2) Gloss: Specular reflectance was measured at 60°C. ◎...85<〇...85-75 △...75-65 ×...65> (3) Adhesion: Remaining of the coating film was examined by peeling with cellophane tape at 1 mm squares. ◎...100/100 〇...100/100~95/100 △...95/100~90/100 ×...90/100> (4) Pencil hardness: 250g load, paint film scratched with Mitsubishi Uni I checked the hardness. (5) Solvent resistance: The condition of the coating film was observed using a spot test of urethane thinner. ◎...No change〇...Slightly softened △...Softened ×...Coating film dissolved (6) Chemical resistance: The condition of the coating film was observed after immersing it in a 5% NaOH aqueous solution for 24 hours. ◎...No change〇...A little blistering occurred △...Blistering occurred ×...Blistering occurred in the paint film (7) Weather resistance: With sunshine type weather-o-meter
The state of the coating film was observed after 4000 hours of irradiation. ◎...no change〇...slight loss of luster △...fading of luster ×...cracks occurred in the paint film (8) Water resistance: Observe the condition of the paint film after soaking in warm water at 50℃ for 3 days did. ◎...No change〇...Few blisters occurred △...Blisters occurred ×...Blistering occurred in the paint film (9) Pot life: Paint adjusted to about 15 seconds with food cup #4 was about 50 Time when the viscosity increased to seconds ◎...More than 10 hours 〇...8 to 10 hours △...6 to 8 hours x...6 hours or less

【table】

【table】

Claims (1)

[Scope of Claims] 1. 1 to 20% by weight of a polymerizable unsaturated monomer (a) containing a carboxyl group and 80 to 99% by weight of other polymerizable unsaturated monomers (b) (provided that (a) + (b) is 100% by weight) is first reacted with an alkylene imine (c) and then with a ketone (d) to obtain a polymer containing a ketimine group. A curable composition comprising ( ) and a compound ( ) containing at least two epoxy groups in the molecule as essential components.