JPH0238090B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ε-caprolactone-modified urethane acrylate oligomer having a tris(2-hydroxyethyl)isocyanurate skeleton. More specifically, the present invention relates to a photocurable urethane acrylate oligomer that provides a cured coating film with excellent flexibility. The photocurable oligomer obtained by the present invention is expected to be applied to flexible vinyl floor tiles, optical fiber covering materials, plastic coatings, etc. One of the recent successes in the trend towards low-pollution, resource-saving, and energy-saving paints is UV-curable paints. It consists of a reactive composition that is substantially free of volatile solvents and contains a reactive diluent that reacts during curing to become part of the protective coating itself. Among these ultraviolet curable coatings, there are those based on urethane acrylate having tris(2-hydroxyethyl)isocyanurate in its skeleton as a representative example.
However, this urethane acrylate-based composition has a very high viscosity, so it can be diluted with a large amount of a highly skin-irritating, low-boiling acrylic reactive diluent to reduce the viscosity. It was necessary to apply the coating to Furthermore, the composition based on this urethane acrylate had a photocured cured coating that was very hard, brittle, and inflexible. Therefore, the present inventors conducted intensive research to improve the drawbacks of coating compositions based on urethane acrylate having a tris(2-hydroxyethyl)isocyanurate skeleton.
hydroxyethyl) isocyanurate or caprolactone-modified tris(2-hydroxyethyl)isocyanurate obtained by ring-opening addition of ε-caprolactone, and hydroxyalkyl (meth)acrylate or ε-caprolactone-modified hydroxyalkyl (meth)acrylate. The photocurable urethane acrylate oligomer obtained by the urethanization reaction with ethylenically unsaturated monoisocyanate obtained by the reaction of organic diisocyanate and organic diisocyanate has a lower viscosity than that unmodified with caprolactone. It has been found that the membrane has improved elongation and tensile strength,
The present invention has been completed. That is, the present invention provides (A) tris(2-hydroxyethyl)isocyanurate and/or ε-caprolactone-modified tris(2-hydroxyethyl)isocyanurate (hereinafter referred to as polyol); and (B) hydroxyalkyl (meth) ) The above (A ), (B) is a method for producing a urethane acrylate oligomer, characterized in that the reaction is carried out in a combination in which at least one of (B) contains an ε-caprolactone modified product. The reaction according to the invention is typically carried out as follows. First, a hydroxyalkyl (meth)acrylate and/or an ε-caprolactone-modified hydroxyalkyl (meth)acrylate is reacted with an organic diisocyanate to produce an ethylenically unsaturated monoisocyanate. This ethylenically unsaturated monoisocyanate is then reacted with the polyol to yield the desired product. The polyol (A) used in the present invention is tris(2-hydroxyethyl)isocyanurate and/or ε
- caprolactone-modified tris(2-hydroxyethyl) isocyanurate, in particular, ring-opening addition polymerization of 0.1 to 10 mole parts of ε-caprolactone to 1 mole part of tris(2-hydroxyethyl) isocyanurate 120-645mg of hydroxyl-terminated polyester compound
Those having a hydroxyl value in the range of KOH/g are preferred. Ring-opening polymerization of ε-caprolactone to the hydroxyl group of tris(2-hydroxyethyl)isocyanurate is carried out at 100-240°C, preferably at 120-200°C, under _N2 atmosphere.
Perform at a temperature of It is preferable to use a catalyst for this reaction. As a catalyst, titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, tetraethyl titanate, tin octylate,
Organic tin compounds such as dibutyltin oxide and dibutyltin dilaurate, as well as stannous chloride, stannous bromide, stannous iodide, and the like can be used. Usage amount starts from 0.1ppm based on the total amount of preparation
It is 1000ppm. The product of such a reaction is actually the formula () (In the formula, m ₁ , m ₂ , m ₃ are each 0 or a positive number, and the average of m ₁ + m ₂ + m ₃ is 0.1 to 10.) It is statistically distributed down to the caprolactone compound. Note that this reaction product does not need to be further separated or purified, and can be used as it is for the next step reaction. The ε-caprolactone-modified tris(2-hydroxyethyl) isocyanurate used here is a viscous liquid that is fluid at room temperature and has excellent reactivity in the next step, producing a highly flexible final product. Becomes the source. Further, in the present invention, the reaction between the acrylic compound having a hydroxyl group and the organic diisocyanate is carried out at a charging molar ratio (former/latter) of about 1/1 and a reaction temperature range of 10 to 90°C, preferably 40 to 60°C. This itself is a conventional reaction. The acrylic compound having a hydroxyl group used in the present invention is a hydroxyalkyl (meth)acrylate and/or a hydroxyalkyl (meth)acrylate modified with ε-caprolactone.
Preferably, 0.2 to 20 mole parts of ε-caprolactone is subjected to ring-opening addition polymerization. Examples of the hydroxyalkyl (meth)acrylate used in the present invention include 2-hydroxyethyl acrylate or methacrylate, hydroxypropyl acrylate or methacrylate, and hydroxypentyl acrylate or methacrylate. Hydroxyethyl (meth)acrylate is particularly effective. The ring-opening polymerization of ε-caprolactone to the hydroxyl group of the hydroxyalkyl (meth)acrylate is carried out in an air atmosphere at a temperature of 70 to 150°C, preferably 80 to 140°C. If the temperature is lower than 70℃, the reaction rate is low;
Further, if the temperature is higher than 150°C, the acrylate group or methacrylate group will undergo radical polymerization. It is preferable to use a catalyst for this reaction. Examples of catalysts include titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate, organic tin compounds such as tin octylate, dibutyltin oxide, and dibutyltin dilaurate, and stannous chloride and stannous bromide.
Tin, stannous iodide, etc. can be used.
The amount used is 0.1ppm to 1000ppm based on the total amount of preparation. Further, during the reaction, it is preferable to add 0.02 to 2% of hydroquinone, hydroquinone monomethyl ether, pt-butylcatechol, phenothiazine, etc. as a radical polymerization inhibitor. The product of such a reaction is actually the formula () (In the formula, R ₁ is hydrogen or methyl group, R ₂ has 2 carbon atoms
-6 alkylene groups, n is 0 or a positive number, and the average of n is 0.2 to 20), and is statistically distributed from unreacted substances to polycaprolactone compounds. Note that this reaction product does not need to be further separated and purified, and can be used as it is for the next step reaction. The ε-caprolactone-modified hydroxyalkyl (meth)acrylate used here is a liquid with fluidity at room temperature, and is a source of excellent reactivity in the next step and a highly flexible final product. Examples of the organic diisocyanate used in the present invention include commercially available tolylene diisocyanate mixtures, hexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate, xylene diisocyanate, isophorone diisocyanate, and the like. Among these, isophorone diisocyanate is particularly preferred because it has good weather resistance and because one isocyanate group is much more reactive than the other, it is easy to synthesize an ethylenically unsaturated monoisocyanate. For the urethanization reaction between the organic diisocyanate and the acrylic compound having a hydroxyl group, any known urethanization catalyst such as amines, tin compounds, or metal acetylacetonate complexes can be used. Examples of the catalyst include triethylenediamine, morpholine, N-ethylmorpholine, piperidine, triethanolamine, triethylamine, dibutyltin dilaurate, stannous octaate, stannous laurate, stannous oleate, stannous torate, dibutyltin oxide, and the like. I can do it. In the present invention, the reaction between the ethylenically unsaturated monoisocyanate and the polyol is carried out at a charging molar ratio (former/latter) of about 3/1 and a temperature range of 60 to 90°C, and is itself a conventional reaction. Further, at this time, a catalyst may or may not be used. When the photocurable oligomer of the present invention is used as a photocurable coating agent, it may be used together with a liquid ethylenically unsaturated compound that acts as a diluent to further lower the viscosity. Examples of the liquid ethylenically unsaturated compound include 2-hydroxyethyl acrylate, phenoxyethyl acrylate, isobornyl acrylate, styrene, vinylpyrrolidone, and tetrahydrofurfuryl acrylate. It is desirable to use these diluents in an amount of 10 to 60% based on the total weight of the oligomer. Particularly preferably 20 to 40%.
Polyfunctional diluents such as trimethylolpropane triacrylate may be present to maintain the unique combination of strength and elongation of this invention by maintaining the distance between the crosslinking sites. , it is preferred to use a monoethylenic diluent. A photosensitizer may be used as appropriate for the coating agent, and ketone photosensitizers such as benzophenone and diethoxyacetophenone, and benzoin ether photosensitizers such as benzoin isobutyl ether and benzoin methyl ether are used. Can be used. If the desired final product is manufactured using the photocurable oligomer according to the present invention, it is possible to form a cured coating film with improved flexibility and excellent adhesion and abrasion resistance. It can be widely used as an excellent material in the fields of vinyl floor tiles, optical fiber coatings, plastic coatings, etc. The tris(2-hydroxyethyl)isocyanurate-based photocurable oligomer of the present invention will be described below with reference to examples, but the present invention is not limited to these. Note that the numbers in the middle part of the example mean parts by weight. Example 1 (B ₁ ) 1140 parts (10.0 mol) of ε-caprolactone and 1160 parts (10.0 mol) of 2-hydroxyethyl acrylate were placed in a 34-necked flask equipped with an air introduction tube, a thermometer, a cooling tube, and a stirring device. , 11.5 parts of hydroquinone monomethyl ether, and 0.115 parts of stannous chloride were added, and the mixture was reacted at 120° C. for about 10 hours while introducing air, and the reaction was stopped when the remaining amount of ε-caprolactone was 1% or less. ε-caprolactone modified 2-
2300 parts of hydroxyethyl acrylate were obtained.
The hydroxyl value of this acrylic compound is 244mg−
It was KOH/g. (B ₂ ) In addition, 2220 parts (10.0 mol) of isophorone diisocyanate and dibutyltin dilaurate were placed in a 55-necked flask equipped with an air introduction tube, a thermometer, a cooling tube, a dropping funnel, and a stirring device.
9.05 parts were added and kept at 60°C under air atmosphere. Furthermore, while maintaining the reaction temperature (below 60°C), the ε-caprolactone modified 2 synthesized in (B ₁ ) was added.
-2300 parts of hydroxyethyl acrylate (10.0
mol) was added dropwise from the dropping funnel over a period of about 2 hours, and after the addition was completed, the reaction was continued at 60°C for about 5 hours, and the reaction was stopped after confirming that no hydroxyl group was present in the reaction product by IR analysis. Liquid ethylenically unsaturated monoisocyanate 4520 as reaction product
I got the department. (C) Next, in a 5-necked flask similar to (B ₂ ),
522 parts (2.0 mol) of tris(2-hydroxyethyl)isocyanurate and 500 parts of methyl ethyl ketone were charged and heated to 80°C. Furthermore, 2712 parts (6.0 mol) of the ethylenically unsaturated monoisocyanate synthesized in (B ₂ ) was added dropwise from the dropping funnel over a period of about 4 hours while maintaining the reaction temperature (80°C or less) in an air atmosphere, and the process was continued for about 5 hours after the completion of the dropping. 80℃
The reaction was continued and stopped when NCO% was 0.01% or less. Subsequently, methyl ethyl ketone was expelled under reduced pressure to obtain 3234 parts of a photocurable oligomer. The viscosity of this oligomer at 25℃ is 11000 cps
It was hot. Example 2 (A) In a 54-necked flask equipped with a nitrogen inlet tube, a thermometer, a cooling tube, and a stirring device, 1277 parts (11.2 mol) of ε-caprolactone and 2923 parts of tris(2-hydroxyethyl)isocyanurate ( 11.2
mol) and 4.2 parts of tetrabutyl titanate and reacted at 170°C for about 6 hours under a nitrogen atmosphere.
The reaction was stopped when the remaining amount of ε-caprolactone was 1% or less. 4,200 parts of ε-caprolactone-modified tris(2-hydroxyethyl)isocyanurate was obtained as a reaction product. The hydroxyl value of this polyol was 449 mg-KOH/g. (C) Next, in the same manner as in (C) of Example 1, 750 parts (2.0
2712 parts (6.0 mole) of the ethylenically unsaturated monoisocyanate synthesized in (B ₂ ) of Example 1
mol) to obtain 3462 parts of a photocurable oligomer. The viscosity of this oligomer at 25℃ is
It was 65000cps. Comparative Example 1 (B) In the same manner as in (B ₂ ) of Example 1, 1160 parts of 2-hydroxyethyl acrylate was reacted with 2220 parts of isophorone diisocyanate (6.76 parts of dibutyltin dilaurate was used as a catalyst) to produce ethylenically unsaturated monoisocyanate. Obtained 3380 copies. (C) Next, Tris (2
-hydroxyethyl) isocyanurate was reacted with 2028 parts of the ethylenically unsaturated monoisocyanate synthesized in (B) above to obtain 2550 parts of a photocurable oligomer. The viscosity of this oligomer at 25°C was over 200,000 cps. Application Example Using the photocurable oligomers shown in Table 1 produced in the same manner as in Comparative Examples, Examples, and the like, a diluent and a photosensitizer were combined, and a cured coating film was obtained by irradiation with ultraviolet rays. The results are shown in Table 1. In the test, a composition containing an oligomer/diluent/photosensitizer (Irgakiyure 651, Ciba Geigy's trade name) in a ratio of 75/25/1.9 (by weight) was applied to glass. Curing was performed by irradiating the coated sample using an 80 W/cm high pressure mercury lamp. The film thickness was approximately 100μ.

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Claims (1)

[Scope of Claims] 1 (A) Tris(2-hydroxyethyl)isocyanurate and/or ε-caprolactone-modified tris(2-hydroxyethyl)isocyanurate (hereinafter referred to as polyol); (B) hydroxyalkyl (meth)acrylate and/or ε-caprolactone-modified hydroxyalkyl (meth)acrylate (hereinafter referred to as an acrylic compound having a hydroxyl group) and an ethylenically unsaturated monoisocyanate obtained from the reaction with an organic diisocyanate, as described above. A method for producing a urethane acrylate oligomer, which comprises reacting in a combination in which at least one of (A) and (B) contains an ε-caprolactone modified product. 2. The urethane acrylate according to claim 1, wherein the polyol is a reaction product obtained by polymerizing 0.1 to 10 moles of ε-caprolactone to 1 mole part of tris(2-hydroxyethyl)isocyanurate. Method for producing oligomers. 3 The acrylic compound having a hydroxyl group is added to 1 mole part of hydroxyalkyl (meth)acrylate,
The method for producing a urethane acrylate oligomer according to claim 1 or 2, which is a reaction product obtained by polymerizing 0.2 to 20 mole parts of ε-caprolactone. 4. The urethane according to claim 1, 2 or 3, wherein the hydroxyalkyl (meth)acrylate is 2-hydroxyethyl acrylate or methacrylate, hydroxypropyl acrylate or methacrylate, hydroxypentyl acrylate or methacrylate. A method for producing acrylate oligomers. 5. Claims 1 to 5, wherein the organic diisocyanate is a tolylene diisocyanate mixture, hexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate, xylene diisocyanate, or isophorone diisocyanate.
A method for producing a urethane acrylate oligomer according to any one of Item 4.