JPH0248013B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a novel curable composition having a terminal highly reactive isocyanate group or having the isocyanate group blocked with a phenol compound. Conventionally, as a means of improving the adhesion and adhesive strength of paints, adhesives, etc., polar groups such as hydroxyl groups and carboxyl groups have been introduced or surface modifiers such as silane coupling agents and titanium coupling agents have been added. However, acrylate and/or methacrylate [hereinafter collectively referred to as (meth)acrylate]
The inventors have now completed the present invention by discovering that adhesion can be significantly improved by introducing a highly reactive isocyanate group and/or an isocyanate group blocked with a phenol compound to the terminal end of the adhesive. That is, in the present invention, 2-hydroxy-3-alkylphenoxypropyl (meth)acrylate represented by the following general formula () is added to 1 mole of the organic diisocyanate represented by the following general formula ().
This is a method for producing a curable composition, which is characterized by blocking the isocyanate groups by reacting 1.5 mol of the compound or by reacting the product obtained by the reaction with a phenol compound represented by the following general formula (). O=C=N-X-N=C=O () However, X is a divalent aliphatic group, an alicyclic group, or an aromatic group. However, R ₁ is hydrogen or a methyl group. R ₂ is carbon number 1
~9 alkyl group. However, R ₃ is hydrogen or a methyl group. The (meth)acrylate having an isocyanate group at the end, which is the main component of the curable composition obtained by the present invention, is a viscous liquid compound, and when mixed with a photopolymerization initiator and exposed to ultraviolet rays, it cures immediately and is desirable. Exhibits various physical properties. Further, as other curing means, curing with an electron beam and curing with a peroxide are also possible. In addition, (meth)acrylate, which is the other main component of the curable composition obtained by the present invention and whose terminal isocyanate group is blocked with a phenol compound, is a viscous liquid compound or a solid compound with a relatively low melting point, and is nontoxic and can be stored easily. It has good stability and, like (meth)acrylates with terminal isocyanate groups, can be heated to 180℃ to 220℃ after curing with ultraviolet rays or electron beams.
By heating for 3 to 5 minutes, the phenol compound is volatilized and exhibits desirable physical properties similar to (meth)acrylates having terminal isocyanate groups. The organic diisocyanate represented by the general formula () that can be used in the present invention is an aliphatic, alicyclic or aromatic diisocyanate,
These compounds are well known to those skilled in the art, and many are commercially available. Examples of these include 2,4- or 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, m- and p-xylylene diisocyanate, tetramethylene diisocyanate, cyclohexane-1, Examples include 4-diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, modified diisocyanates thereof, and hydrogenated diisocyanates, and these diisocyanates may be used alone or in combination of two or more. Among these, aliphatic diisocyanates and alicyclic diisocyanates are preferred because they have a lower viscosity than aromatic diisocyanates. 2-Hydroxy-3-alkylphenoxypropyl (meth)acrylate represented by the following general formula () is However, R ₁ is hydrogen or a methyl group. R ₂ is hydrogen or an alkyl group having 1 to 9 carbon atoms. (Meth)acrylic acid represented by the general formula () However, R ₁ is the same as formula (). Alkyl phenyl glycidyl ether represented by the general formula () However, R ₂ is the same as formula (). It is obtained by reacting in a manner known to those skilled in the art. For example, among the compounds of formula (), 2-hydroxy-3-
Phenoxypropyl acrylate (R ₁ = H, R ₂
=H), 1 mole of phenyl glycidyl ether, 1 mole of acrylic acid, a quaternary ammonium salt as a catalyst, a polymerization inhibitor, and toluene as a solvent, at 70 to 110°C, the acid value is approximately "O ”
After washing the reaction solution, the toluene is distilled off. 2-hydroxy-3 represented by general formula ()
Among the -phenoxypropyl acrylates, those in which R ₂ is an alkyl group having 1 to 4 carbon atoms are preferred. When R ₂ is an alkyl group having 5 or more carbon atoms, the adhesive strength of the resulting curable composition tends to decrease. General formula () However, R ₃ is hydrogen or a methyl group. The phenol compound represented by is specifically phenol, O-, m-, P-cresol, and mixtures thereof. In producing the curable composition of the present invention, organic diisocyanate () and 2-hydroxy-3
- The ratio of alkylphenoxypropyl (meth)acrylate () is ()/ in order to leave a highly reactive isocyanate group at the terminal
The molar ratio of () is 2.0 or less, that is, () is 33 mol
% or more, but in order to achieve the purpose of the present invention, () should be 1.5% per mol of ().
It is necessary that the amount is less than mol. On the other hand, organic diisocyanate () is highly toxic, and in order to keep the amount of organic diisocyanate () remaining in the reaction product as low as possible, the content of () must be 50 mol% or less. Therefore, the ratio of () and () is 1.0 to 1.5 moles of () to 1 mole of ().
It is in the molar range. When blocking the isocyanate group of the (meth)acrylate containing a terminal isocyanate group, which is the reaction product of () and () above, with alkylphenol (), () is required in an equimolar amount to the remaining isocyanate group, and therefore ( ), (),
Optimally, the ratio of () to 1 mole of () is in the range of 1.0 to 1.5 moles, and 0.5 to 1 mole of (), and the total amount of () and () is 2 moles or more. The catalyst used in the reaction is any one of the known urethanization catalysts, such as amine compounds or tin compounds, and the amount added is a conventional amount known to those skilled in the art. Examples of these include triethylenediamine, N-alkylmorpholine, triethylamine, pyridine, dibutyltin dilaurate, stannous octoate, dioctyltin diacetate, and the like. The reaction can be carried out without a solvent or with a solvent that is non-reactive with respect to isocyanate groups. Reaction solvents include commonly used reaction solvents such as benzene, toluene, xylene, methyl ethyl ketone, and methyl isobutyl ketone, as well as butyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, and hexane. Compounds that are inactive toward isocyanate groups, such as liquid acrylates such as diol diacrylate, trimethylolpropane triacrylate, and polyester acrylate, can be mentioned. The novel curable composition obtained by the present invention can be used alone or in the form of a mixture with other known non-reactive or reactive solvents, resins, oligomers, pigment dispersants, etc. that are commonly added to paints and adhesives. used. Further, the curable composition can be cured by radiation such as ultraviolet rays or electron beams, or by peroxide, and any of these can be cured by known methods. When curing is carried out using ultraviolet light, for example, the amount of photopolymerization initiator is 0.1 to 15% by weight, preferably 1 to 5% by weight.
Add at a concentration of These photopolymerization initiators can be used alone or as a mixture, or in combination with known accelerators. Examples of these photopolymerization initiators include benzophenone, benzoin, benzoin ethers, acetophenone, thioxanthone, and benzyl. The novel curable composition obtained by the present invention is easily cured by ultraviolet rays, electron beams, and peroxides, and has excellent adhesion and adhesive properties, making it useful as paints and adhesives. The present invention will be explained in more detail with reference to Examples and Comparative Examples below. In addition, parts in each example represent parts by weight. Example 1 and Comparative Example 1 78 parts of tolylene diisocyanate, 0.1 part of dibutyltin dilaurate, and 0.04 part of hydroquinone monomethyl ether were charged into a reactor equipped with a stirrer, a thermometer, and a dropping funnel and heated to 70°C. Next, 111 parts of 2-hydroxy-3-phenoxypropyl acrylate (trade name Aronix M-5700, manufactured by Toagosei Kagaku Kogyo Co., Ltd.) was added from the dropping funnel at a temperature of 70~
The mixture was added dropwise over approximately 1 hour while maintaining the temperature at 80°C. Thereafter, stirring was continued for 1 hour at 80°C to complete the reaction. The physical properties of the obtained curable composition were as shown in Table 1. Further, the physical properties of 2-hydroxy-3-phenoxypropyl acrylate (Aronix M-5700) are shown in Table 1 as Comparative Example 1. Examples 2 to 6 A reaction was carried out in the same manner as in Example 1 using the raw material compositions shown in Table 1 to obtain curable compositions. Table 1 shows the physical properties of the obtained composition.

[Table] Table 1 shows that the adhesive using the curable composition of the present invention has significantly improved adhesive properties. Table 2 shows the refractive index of the compositions of Examples 1 to 6.

【table】

[Table] Example 7 After carrying out the reaction in the same manner as in Example 1, 0.5 part of dibutyltin dilaurate was added, and phenol 38
The mixture was added dropwise over 30 minutes while maintaining the temperature at 80°C to 100°C. Thereafter, stirring was continued for 2 hours at 100°C to complete the reaction. The physical properties of the obtained composition were as shown in Tables 3 and 4. Examples 8 to 10 A curable composition was obtained by carrying out the reaction in the same manner as in Example 7 except that the phenol in Example 7 was changed to 43 g of P-cresol. The various physical properties were as shown in Tables 3 and 4.

【table】

[Table] Table 5 shows the results of elemental analysis of the compositions of Examples 7 to 10.

【table】

Claims (1)

[Scope of Claims] 1 1 to 1.5 moles of 2-hydroxy-3-alkylphenoxypropyl (meth)acrylate represented by the following general formula () per 1 mole of an organic diisocyanate represented by the following general formula (). A method for producing a curable composition, which comprises blocking isocyanate groups by reacting or reacting a product obtained by the reaction with a phenol compound represented by the following general formula (). O=C=N-X-N=C=O () However, X is a divalent aliphatic group, an alicyclic group, or an aromatic group. However, R ₁ is hydrogen or a methyl group. R ₂ is carbon number 1
~9 alkyl group. However, R ₃ is hydrogen or a methyl group.