JPH0518869B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new and useful thermosetting resin composition, and more particularly, it contains a hydroxyl group-containing compound and a specific alkoxysilane-modified resin as essential components, and does not generate harmful substances during curing. It has excellent curability and can provide a cured product with good physical properties and solvent resistance.
The present invention relates to resin compositions useful as paints, adhesives, sealants, general molding, and the like. In recent years, there has been a growing trend toward non-polluting paints in fields such as the paint industry. Conventional thermosetting resin compositions, such as polyurethane paints that use polyisocyanate as a curing agent, have problems with toxicity due to raw isocyanate remaining in the polyisocyanate resin that is the curing agent. Melamine paints that use hardening agents have had the problem of generating toxic formaldehyde during curing. Furthermore, even when a hydroxyl group-containing polymer is used with blocked isocyanate as a curing agent, the curing temperature is high. As a result of extensive research in view of the above points, the present inventors have found that a hydroxyl group-containing compound is modified with a trialkoxysilyl group-containing compound (alkoxysilane-modified resin).
By blending, it has excellent curability and
The inventors of the present invention have completed the present invention by discovering that a cured coating film with good physical properties and solvent resistance can be obtained from a composition that does not generate harmful substances during curing. That is, the present invention includes a compound (A) having a hydroxyl group as an essential component, and a combination of the compound (A) and the general formula [However, R ¹ , R ² and R ³ in the formula are each,
Monovalent hydrocarbons with linear or branched alkyl groups, alkyl groups substituted with halogen atoms or alkoxy groups, phenyl groups, nuclear-substituted phenyl groups, or aralkyl groups, which may be the same or different; shall represent the group. ] We provide a thermosetting resin composition comprising an alkoxysilane modified resin (B) obtained by reacting with a compound having at least one trialkoxysilyl group per molecule represented by The composition of the present invention having such a structure can be widely used not only as a paint but also as an adhesive, a sealant, or for general molding. The above-mentioned hydroxyl group-containing compound (A) constituting the composition of the present invention refers to a compound having at least one, preferably two or more hydroxyl groups per molecule, and representative examples of such hydroxyl group-containing compound (A) Examples include saturated or unsaturated polyester resins,
Resins containing hydroxyl groups (hereinafter abbreviated as hydroxyl group-containing resins) such as alkyd resins, hydroxyl group-containing vinyl polymers, polyurethane resins, polybutadiene glycols, or epoxy resins,
Or unsaturated monohydric alcohols such as oleyl alcohol, linoleyl alcohol or linolenyl alcohol; partial esterification products of unsaturated fatty acids and polyhydric alcohols such as oleic acid, linoleic acid or linoleic acid; ethylene glycol, diethylene glycol, Polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, cyclohexanedimethanol, neopentyl glycol, glycerin, 3 - polyhydric alcohols such as methylpentane-1,3,5-triol, trimethylolpropane, pentaerythritol or sorbitol; and also obtained by reacting various hydroxyl group-containing compounds as described above with ε-caprolactone. There are ester compounds containing a hydroxyl group. Among them, in order to prepare the above-mentioned hydroxyl group-containing vinyl polymer, a mixture of a hydroxyl group-containing vinyl monomer and another vinyl monomer copolymerizable with the monomer is polymerized. Alternatively, a vinyl acetate homopolymer or copolymer may be hydrolyzed. Typical vinyl monomers containing hydroxyl groups include hydroxyalkyl esters of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate, and N-methylol ( meth)acrylamide, etc. On the other hand, typical examples of other vinyl monomers that can be copolymerized with such hydroxyl group-containing vinyl monomers include methyl (meth)acrylate,
(meth)acrylic acid esters such as ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate or benzyl (meth)acrylate; monoalkyl or dialkyl esters of dibasic acids such as styrene;
Aromatic vinyl compounds such as α-methylstyrene or vinyltoluene; also vinyl acetate, vinyl chloride, (meth)acrylonitrile, N,N-
dialkylaminoalkyl (meth)acrylate (meth)acrylic acid, crotonic acid, itaconic acid,
Examples include fumaric acid, maleic anhydride, maleic acid, N-alkoxymethyl (meth)acrylamide, and (meth)acrylamide. In order to prepare the above-mentioned vinyl polymer, any known method such as solution, bulk or suspension polymerization can be used, but solution radical polymerization is most preferred. In order to prepare a polyester resin or an alkyd resin containing a hydroxyl group, known alcohols and carboxylic acids may be reacted by a known method. Furthermore, as for the polyurethane resin or epoxy resin containing hydroxyl groups, those synthesized by known methods can be used as they are, or those which have been further modified by known methods to introduce hydroxyl groups can be used. Next, the alkoxysilane-modified resin (B), which is the other component constituting the composition of the present invention, is composed of the above-mentioned hydroxyl group-containing compound (A) and the above-mentioned trioxysilane-containing compound (A) as shown in the above-mentioned general formula []. It refers to a compound obtained by reacting with a compound having at least one alkoxysilyl group in one molecule, but as one of the reaction components, a hydroxyl group-containing compound, the compound (A) as described above can be used as is. However, in particular, it is preferable to use hydroxyl group-containing ester compounds obtained by reacting various hydroxyl group-containing compounds with ε-caprolactone from the viewpoint of flexibility and adhesion of the cured resin. while methanol, ethanol, n-propanol, n
Also included are hydroxyl group-containing oligoesters obtained by addition reaction of saturated monohydric alcohols such as -butanol or 2-ethylhexanol with ε-caprolactone. As the hydroxyl group-containing compound, unsaturated monohydric alcohols as mentioned above can also be used as they are. The ε-caprolactone adduct of such a hydroxyl group-containing compound is preferably one in which about 1 to 20 moles of ε-caprolactone are added to 1 equivalent of the hydroxyl group in the presence of a known and commonly used catalyst. On the other hand, typical compounds having at least one trialkoxysilyl group per molecule, which are the other reaction components, include tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, and tetra(2-methoxyethyl).
silicic ester acids such as silicate, tetra(2-chloroethyl) silicate, tetraphenyl silicate or tetrabenzyl silicate; condensates of the above silicic esters such as tetraethyl silicate dimer, tetraethyl silicate tetramer or tetraethyl silicate hexamer; Silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane or glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, or 3-(β-aminoethyl)aminopropyltrimethoxysilane; trimethoxy Hydrosilanes such as silane or triethoxysilane; or compounds having one or more allylic double bonds per molecule such as allyl acetate, allyl benzoate, diallyl phthalate, diallyl adipate, diallyl succinate or triallyl trimellitate; Additives with the above-mentioned hydrosilanes; and vinyl polymers containing alkoxysilyl groups in their side chains. These may be used alone or as a mixture of two or more. Among these, from the viewpoint of cost, it is particularly preferable to use silicic acid esters such as tetramethyl silicate or tetraethyl silicate, or condensates thereof. In order to obtain the modified resin (B) using both of these reaction components, it is sufficient to react them at 60 to 200°C in the presence of a known and commonly used catalyst. The alcohol produced by charging and heating may be removed from the system under normal pressure or reduced pressure, or the alcohol produced may be removed by dropping the hydroxyl group-containing compound component into a mixture of the trialkoxysilyl group-containing compound component and the catalyst. The reaction may be carried out by distilling it off. At this time, when the content of hydroxyl groups per molecule of the hydroxyl group-containing compound component is high, gelation tends to occur if the components are charged all at once and reacted, so it is preferable to carry out the modification reaction by a dropping method. Catalysts (ester exchange catalysts) that can be used in this case include titanium compounds such as tetraisopropyl titanate or tetrabutyl titanate; acidic catalysts such as sulfuric acid, phosphoric acid, alkylated phosphoric acid, or hydrochloric acid; or lithium hydroxide, sodium hydroxide, water Typical examples include potassium oxide, sodium methylate, or alkaline substances such as triethylamine or tributylamine, and among these, it is particularly preferable to use titanium compounds. The ratio of both reaction components used in such a modification reaction is such that the trialkoxysilyl group in the trialkoxysilyl group-containing compound is 0.6 to 10 equivalents per equivalent of the hydroxyl group contained in the hydroxyl group-containing compound;
The amount is preferably selected to be 0.8 to 10 equivalents. When this equivalent ratio is less than 0.6, gelation tends to occur during the reaction, which is not preferable; however, even if it is used in a large amount exceeding 10 equivalents, there is no adverse effect on the synthesis or on the properties of the resulting resin. , from the point of view of price alone, it is better to reduce the amount to 10 equivalents or less. During such modification reactions, the reaction temperature (usually
When the hydroxyl group-containing compound is a liquid substance at 100 to 140°C, it can be carried out without using a solvent, but if the compound is a solid substance,
Alternatively, if the compound and the trialkoxysilyl group-containing compound do not mix uniformly at such temperatures, it is preferable to use a solvent with a relatively high boiling point that does not react with both of the reaction components. Typical examples include butyl acetate, xylene, "cellosolve acetate," cyclohexanone, or methyl isobutyl ketone. In addition, even if the trialkoxysilyl group-containing compound is used in excess of the hydroxyl group-containing compound as a partner component during such modification reactions, unreacted components may be contained in the reaction system as long as there is no problem. It can be used as it is as component (B) of the composition of the present invention, and of course, in cases where unreacted trialkoxysilyl group-containing compounds remain and give unfavorable results in terms of performance, It can also be removed by methods such as vacuum distillation. The composition of the present invention contains the above-mentioned hydroxyl group-containing compound (A) and alkoxysilane-modified resin (B) as essential components; % and component (B) in a range of 5 to 95% by weight, and if necessary, the composition of the present invention may contain a compound that reacts with hydroxyl groups to cause crosslinking. A crosslinking agent (C) component such as the following may be blended. Typical crosslinking agents (C) include amino resins, polyisocyanate compounds, block isocyanate compounds, and epoxy resins, but these may be used in amounts within a range that does not impair the features of the present invention. Among these, representative examples of amino resins include those obtained by methylolizing an amino group-containing compound such as melamine, benzoguanamine, or urea, and then converting it into alkyl ether, while polyisocyanate compounds include polyisocyanate compounds such as trimethylolethane or trimethylolpropane. Isocyanate group-containing resins (isocyanate prepolymers) obtained by adding alcohols with polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, tolylene diisocyanate, xylene diisocyanate or diphenylmethane diisocyanate, or the above-mentioned polyisocyanate Isocyanurate ring-containing polyisocyanates obtained by trimerizing isocyanates are typical, and block isocyanate compounds include the aforementioned various polyisocyanates or polyisocyanate resins, alcohols, phenols, and oximes. Typical examples include those obtained by reacting with blocking agents such as lactams; further epoxy resins include diglycidyl ethers of bisphenol A or bisphenol F; diglycidyl esters of polyhydric carbons; Typical examples include polyglycidyl ethers of novolak resin; or polyhydric alcohols and polyglycidyl ethers; other examples include polyaziridine compounds, polyoxazine compounds, polyoxazoline compounds, and polyoxazolidine compounds. The amount of the crosslinking agent (C) component to be used is based on 100 parts by weight of the total solid content of both components (A) and (B).
Preferably, it weighs less than 50% by weight. The composition of the present invention itself has good curability even without the addition of a catalyst, but if it is necessary to further lower the curing temperature or shorten the curing time, it may be necessary to use (B) as described above. Transesterification catalysts such as those used in preparing the components can be added. Also, amines, alkali metal hydroxides or tin, zinc,
Catalysts for hydrolysis-condensation of hydrolyzable silyl groups, such as salts of metals such as lead, cobalt or calcium, may be added. Furthermore, the composition of the present invention includes inorganic pigments including titanium oxide, organic pigments, fillers,
Dyes, flow control agents, anti-color separation agents or cellulose derivatives such as nitrocellulose or cellulose acetate butyrate may also be added. The composition of the present invention thus obtained can be used not only as a solution type or solvent-free liquid composition, but also as a solid composition such as a powder coating. The composition obtained in this way does not generate harmful substances during curing, has excellent curability, and has an
By drying at 200℃ for about 10 to 40 minutes, a cured product with good physical properties and solvent resistance is obtained, so it can be used in various applications such as paints, adhesives, sealants, and general molding. . Next, the present invention will be explained in more detail with reference to Examples. In the following, all parts and percentages are based on weight unless otherwise specified. Reference Example 1 (Preparation example of hydroxyl group-containing compound (A)) 134 parts (1 mol) of trimethylolpropane and 684 parts (684 parts of ε-caprolactone) were placed in a reactor equipped with a stirring device, a thermometer, a nitrogen inlet tube, and a cooling tube. mole)
and 0.04 part of tetrabutyl titanate, heated to 180°C under a nitrogen atmosphere, and kept at the same temperature for 6 hours to form an adduct (A-1) with a molar ratio of trimethylolpropane and ε-caprolactone of 1:6. )
I got it. Reference Example 2 (Preparation example of hydroxide-containing compound (A)) In a reactor similar to Reference Example 1, 126 parts (1 mol) of hexamethylene diisocyanate and the adduct (A-1) obtained in Reference Example 1 were added. 1636 parts (2 moles) and 0.88 parts of dibutyltin dilaurate (corresponding to 500 ppm based on the total amount of hexamethylene diisocyanate and (A-1)) were charged, and the temperature was raised to 80°C under a nitrogen atmosphere. The temperature was maintained for 10 hours to obtain a hydroxyl group-containing urethane resin (A-2). Reference Example 3 (Preparation Example of Alkoxysilane Modified Resin (B)) In a reactor similar to Reference Example 1, 62 parts (1 mole) of ethylene glycol and 664 parts (664 parts) of ε-caprolactone were added.
mol) and 0.04 part of tetrabutyl titanate were charged, the temperature was raised to 180°C under a nitrogen atmosphere, and the temperature was maintained for 6 hours to obtain an adduct with a molar ratio of ethylene glycol and ε-caprolactone of 1:6. . Next, this adduct was cooled to 90°C and 624 parts of tetraethylsilicate was added (the equivalent ratio of tetraethylsilicate and hydroxyl groups in the adduct at this time was
It is 1.5. ) and 4.1 parts of tetrabutyl titanate were added and the temperature was raised to 120°C under a nitrogen atmosphere to distill off the ethanol, and then the reaction was continued at the same temperature for 3 hours until no more ethanol was distilled off to modify the ethyl silicate. Resin (B-1)
I got it. Reference Example 4 (Preparation example of alkoxysilane modified resin (B)) In a reactor similar to Reference Example 1, 818 parts (1 mol) of the adduct (A-1) obtained in Reference Example 1 and tetraethyl silicate were added. 936 parts (The equivalent ratio of tetraethyl silicate to the hydroxyl group in the adduct is
It is 1.5. ) and 5.26 parts of tetrabutyl titanate.
-2) was obtained. Reference Example 5 (Preparation Example of Alkoxysilane Modified Resin (B)) In a reactor similar to Reference Example 1, 818 parts (1 mol) of the adduct (A-1) obtained in Reference Example 1 and "ethyl Silicate 40” (manufactured by Nippon Colcoat Co., Ltd., a mixture of tetra-, penta- and hexamers of ethyl silicate)
A modified resin (B-3) was obtained by charging 2230 parts and 9.2 parts of tetrabutyl titanate, heating at 100 to 135°C for 2 hours, and performing a transesterification reaction while distilling off the produced ethanol. Reference Example 6 (Preparation example of alkoxysilane modified resin (B)) In a reactor similar to Reference Example 1, 640 parts of xylene,
235 parts of "cellosolve acetate" and 175 parts (1.54 mol) of ε-caprolactone were charged, and the temperature was raised to 125°C under a nitrogen stream. Then styrene at the same temperature
200 parts, methyl methacrylate 100 parts, n-butyl acrylate 250 parts, n-butyl methacrylate 250 parts, β-hydroxyethyl methacrylate
A mixture consisting of 200 parts (1.54 moles), 300 parts of xylene, 58.8 parts of t-butylperoxy-2-ethylexanoate, and 5.9 parts of di-t-butyl peroxide was added dropwise over a period of 5 hours. One hour after the completion of the dropwise addition, 0.18 part of zinc acetylacetonate was added and the mixture was further maintained at 125°C for 15 hours to obtain a hydroxyl group-containing acrylic resin modified with ε-caprolactone. Next, a mixture of 480 parts of tetraethyl silicate and 5 parts of tetrabutyl titanate was heated to 110°C under a nitrogen atmosphere, and 2410 parts of the modified acrylic resin prepared earlier (tetraethyl silicate and modified acrylic resin were mixed together) was heated to 110°C. ) was added dropwise over 2 hours to carry out an ester conversion reaction, and the resulting ethanol was distilled off. After that, until no more ethanol is distilled out,
The reaction was continued at 110 to 130°C for 1.5 hours to obtain a tetraethylsilicate-modified acrylic resin (B-4). Reference Example 7 [Example of Preparation of Alkoxysilane Modified Resin (B)] In a reaction vessel similar to Reference Example 1, 850% of linseed oil was added.
184 parts of glycerin and 0.2 parts of litharge were charged, the temperature was raised to 240°C under a nitrogen atmosphere, and the temperature was maintained at the same temperature for 1 hour to carry out transesterification to prepare an unsaturated fatty acid monoglyceride.
Hereinafter, this will be abbreviated as (A-3). Next, the temperature of the reaction mixture was lowered to 40°C, and then 1498 parts of tetraethyl silicate (the equivalent ratio of tetraethyl silicate to the hydroxyl group in the monoglyceride at this time was 1.2) and 7.6 parts of tetrabutyl titanate were added. under a nitrogen atmosphere.
Raise the temperature to 120℃ to distill off the ethanol,
After that, ethanol was distilled off at the same temperature.
Thereafter, the reaction was continued at the same temperature for 4 hours until no more ethanol was distilled out, to obtain an ethylsilicate modified resin (B-5). Reference Example 8 [Example of Preparation of Alkoxysilane Modified Resin (B)] Into the same reaction vessel as in Reference Example 1, 268 parts of oleyl alcohol, 228 parts of ε-caprolactone, and 0.05 parts of tetrabutyl titanate were charged, and the mixture was placed in a nitrogen atmosphere. Below, the temperature was raised to 180°C and maintained at the same temperature for 4 hours to obtain an adduct of oleyl alcohol and ε-caprolactone in a molar ratio of 1:2. The reaction mixture was then cooled to 40°C, and then
Add 372 parts of "ethyl silicate 40" and 2.6 parts of tetrabutyl titanate, raise the temperature in a nitrogen atmosphere, hold at 100-135°C for 3 hours, and distill off the ethanol produced. At the same time, the desired modified resin (B-
6) was obtained. Reference Example 9 [Preparation Example of Alkoxysilane Modified Resin (B)] Into the same reaction vessel as in Reference Example 1, 130 parts of 2-ethylhexanol, 228 parts of ε-caprolactone, and 0.04 parts of tetrabutyl titanate were charged. The temperature was raised to 180°C under a nitrogen atmosphere and maintained at the same temperature for 4 hours to obtain an adduct of 2-ethylhexanol and ε-caprolactone in a molar ratio of 1:2. The reaction mixture was then cooled to 40°C, and then
Add 372 parts of "ethyl silicate 40" and 2.2 parts of tetrabutyl titanate, raise the temperature in a nitrogen atmosphere, hold at 100-135°C for 3 hours, and distill off the ethanol produced. At the same time, the desired modified resin (B-
7) was obtained. Reference Example 10 [Example of Preparation of Alkoxysilane Modified Resin (B)] Addition of trimethylolpropane and ε-caprolactone obtained in Reference Example 1 at a molar ratio of 1:6 was added to the same reaction vessel as in Reference Example 1. of thing (A-1)
818 parts and 684 parts of tetramethyl silicate [this time, the tetramethyl silicate and the adduct (A-
The equivalent ratio with the hydroxyl group in 1) is 1.5. ] and 4.5 parts of tetrabutyl titanate were charged, and the temperature was raised to 110°C under a nitrogen atmosphere. At the same temperature, until no more methanol is distilled out.
The reaction was carried out for 3 hours to obtain a methyl silicate modified resin (B-8). Reference Example 11 [Example of Preparation of Alkoxysilane Modified Resin (B)] Addition of trimethylolpropane and ε-caprolactone obtained in Reference Example 1 at a molar ratio of 1:6 was added to the same reaction vessel as in Reference Example 1. of thing (A-1)
818 parts and 801 parts of methyltriethoxysilane [The equivalent ratio of methyltriethoxysilane to the hydroxyl group in the adduct (A-1) in this case is 1.5. ]
and 4.3 parts of tetrabutyl titanate were charged, and the temperature was raised to 120°C under a nitrogen atmosphere. At the same temperature, until no more methanol is distilled out.
The reaction was carried out for 3 hours to obtain a methyltriethoxysilane modified resin (B-9). Examples 1 to 13 Using the respective hydroxyl group-containing compounds and modified resins obtained in Reference Examples 1 to 11, and further using commercially available hydroxyl group-containing compounds and crosslinking agent (C) component,
A composition (clear paint) of the present invention was prepared by mixing each component in the proportions shown in Table 1. The paint thus obtained was diluted with a mixed solvent of toluene/n-butanol = 6/4 (weight ratio) to the desired spray viscosity, and then sprayed on a zinc phosphate-treated steel plate to a film thickness of approximately 40 μm. A cured coating film was obtained by spray-coating and then baking and drying under the curing conditions shown in the same table.

【table】

[Table] As is clear from the results in Table 1, it is known that the composition of the present invention has excellent curability and provides a cured coating film with good physical properties and solvent resistance.

Claims (1)

[Claims] 1. A hydroxyl group-containing compound (A) and the above-mentioned compound (A)
and the general formula [However, R ¹ , R ² and R ³ in the formula are each,
Monovalent hydrocarbons, which may be the same or different, and are linear or branched alkyl groups, alkyl groups substituted with halogen atoms or alkoxy groups, phenyl groups, nuclear-substituted phenyl groups, or aralkyl groups. shall represent the group. ] The alkoxysilane-modified resin (B) obtained by reacting with a compound having at least one trialkoxysilyl group per molecule represented by the above as an essential component, and 95 to 5 of the former compound (A). weight%
and 5 to 95% by weight of the latter modified resin (B).