JPH0473448B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a resin composition that is cured by irradiation with radiation to form a cured film with excellent heat resistance and flexibility. (Prior Art) Radiation-curable resin compositions that are cured by irradiation with radiation such as ultraviolet rays and electron beams are used for various purposes such as printing inks, paints, coatings for electronic components, and solder resist inks. ing. Its advantage is that it is solvent-free and low-pollution.
Curing speed is extremely fast and product productivity is high.
Since it cures as a 100% solid content, the volume change before and after curing is extremely small. No heat loss through the material or thermal effects on the material. etc. Radiation-curable paints, inks, coating agents for electronic parts, etc. that have these characteristics have excellent adhesion,
Resins exhibiting excellent properties such as water resistance and heat resistance are preferred. As a resin having such characteristics, a radiation-curable resin containing an acrylic ester of tris(2-hydroxyethyl) isocyanate as a main component has been proposed. (Problem to be solved by the invention) However, although this resin has excellent heat resistance,
It has the disadvantage of being hard and brittle. For example, when used as ink for paper, cracks occur in the ink when the paper is bent. Furthermore, when used as a paint on a metal plate such as iron or aluminum, if the plate coated with the paint is bent, the coating will crack and cannot be processed. Therefore, the present inventors conducted intensive studies to take advantage of the heat resistance and water resistance of the tris(2-hydroxyethyl) isocyanurate skeleton, and to improve its disadvantages of being hard and brittle. Acrylate resin or methacrylate resin obtained by reacting acrylic acid or methacrylic acid with lactone-modified tris(2-hydroxyethyl) isocyanurate obtained by ring-opening polymerization of ε-caprolactone adheres to the hydroxyl group of hydroxyethyl) isocyanurate. The present inventors have discovered that a radiation-curable resin composition can be obtained that has excellent properties, water resistance, heat resistance, and extremely good flexibility, and has completed the present invention. (Structure of the Invention) In other words, the present invention provides “(A) an acrylate resin or a methacrylate resin represented by the general formula ()”
15-100 parts by weight 《However, in the formula, L ¹ is , L ² is , L ³ is represents. n1, n2, and n3 are each 0 or a positive integer from 1 to 10, and n1, n2, and n3 cannot be 0 at the same time. R ¹ , R ² , R ³ are -H or

[Formula] Ma Taha

[Formula] is shown, and R ¹ , R ² and R ³ cannot be -H at the same time. 》 (B) Vinyl compound with ethylenically unsaturated bond
85 to 0 parts by weight of a photoinitiator (C) and 0.01 to 10 parts by weight of a photoinitiator (C). The acrylate resin or methacrylate resin represented by the general formula () in the present invention is tris(2-hydroxyethyl)isocyanurate with ε
- Obtained by reacting lactone-modified tris(2-hydroxyethyl) isocyanurate, which is obtained by ring-opening addition polymerization of caprolactone and is represented by the general formula (), with acrylic acid or methacrylic acid. (In the formula, n ₁ , n ₂ , n ₃ are 0 or positive integers from 1 to 10.
n ₁ , n ₂ , and n ₃ cannot be 0 at the same time. ) The ε-caprolactone used in the present invention is industrially produced by oxidizing cyclohexanone with peracetic acid by Bayer-Villiger reaction. Modified tris(2-hydroxyethyl) of the present invention
When producing isocyanurate, the reaction ratio of tris(2-hydroxyethyl)isocyanurate and ε-caprolactones is 1:1 to 1 in molar ratio.
It was 1:30. If the amount of ε-caprolactone is too small from the above range, sufficient flexibility cannot be imparted, and if it is too large, the heat resistance characteristic of tris(2-hydroxyethyl)isocyanurate cannot be fully utilized. In the present invention, when 1 mol of ε-caprolactones is reacted with 1 mol of tris(2-hydroxyethyl)isocyanurate, tris(2-hydroxyethyl)
- The (addition) reaction rate of ε-caprolactones to the hydroxyl group of hydroxyethyl isocyanurate and the (addition) reaction rate of ε-caprolactones to the hydroxyl group of the caprolactone terminal of the product are almost unchanged, and the reaction occurs at any position of the hydroxyl group, so the reaction product is actually a compound represented by the formula (), from unreacted substances where n ₁ = n ₂ = n ₃ = 0,
The result is a mixture that is statistically distributed up to polycaprolactone in which n ₁ , n ₂ , and n ₃ are arbitrary numbers. There is no need to further separate or purify this mixture, and the mixture can be used as is in the synthesis of the final resin. The polymerization reaction of ε-caprolactone to the primary hydroxyl group of tris(2-hydroxyethyl) isocyanurate of the present invention is carried out at 100 to 240°C under a nitrogen atmosphere.
Preferably it is carried out at a temperature of 120 to 200°C. 100
The reaction rate is low when the temperature is lower than 240℃.
If the temperature is higher, ε-caprolactones will boil;
This is because they escape out of the reaction system. 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, stannous bromide, and stannous iodide. A tin halide compound such as tin can be used. The amount used is 0.01~ for the total amount of preparation.
1000ppm, preferably 0.2-500ppm. The reaction may be carried out without a solvent, or with toluene,
The reaction may be carried out in a solvent having no active hydrogen such as xylene, methyl ethyl ketone, methyl isobutyl ketone or the like. However, solvents having ester bonds are not preferred. This is because a transesterification reaction with the ester group of polycaprolactone may occur during the reaction, resulting in the production of polycaprolactone that is not bonded to tris(2-hydroxyethyl)isocyanurate. The modified tris(2-hydroxyethyl)isocyanurate thus obtained is reacted with acrylic acid or methacrylic acid. The reaction ratio is to react 1 mole of modified tris(2-hydroxyethyl) isocyanurate with 1 mole to 10 moles of acrylic acid or methacrylic acid. Since modified tris(2-hydroxyethyl) isocyanurate has three hydroxyl groups in one molecule, if the reaction ratio is 1:1, one of the three hydroxyl groups will be an acrylic group or a methacrylic group. When the reaction ratio is 1:3, acrylic or methacrylic groups are introduced into all hydroxyl groups, and when the reaction is performed at a higher ratio, excess acrylic acid or methacrylic acid remains in the reaction system or after the reaction. It will be removed. If the ratio of acrylic acid or methacrylic acid is lower than the above reaction ratio, the resulting resin will have extremely poor UV curability. Also, if the ratio is high,
Acrylic acid or methacrylic acid is wasted. The reaction can be carried out under the same conditions as those used to synthesize ordinary acrylic acid or methacrylic esters. The thus obtained acrylate or methacrylate resin represented by the general formula () 15~
To 100 parts by weight, preferably 20 to 80 parts by weight, 85 to 0 parts by weight, preferably 80 to 20 parts by weight, of a vinyl compound having an ethylenically unsaturated bond is added. If there is too little acrylate or methacrylate resin, it may not be possible to provide sufficient adhesion, heat resistance, or flexibility to the cured coating, and if there is too much, the viscosity may be high, making it difficult to handle or slowing down the curing speed. There are cases where The vinyl compound having an ethylenically unsaturated bond used in the present invention is an acrylic ester or methacrylic ester compound represented by the general formula (), a radically polymerizable double polymer represented by styrene, N-vinylpyrrolidone, etc. It is a low viscosity liquid compound with a bond. Typical acrylic acid or methacrylic esters are as follows. Monofunctional (meth)acrylic esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, acrylic ester of tetrahydrofurfuryl alcohol, phenoxyethyl acrylate, etc. , 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, neopentyl glycol diacrylate, and other difunctional (meth)acrylic esters, trimethylolpropane Trifunctional (meth)acrylic acid esters such as triacrylate and pentaerythritol triacrylate are used. These vinyl compounds having ethylenically unsaturated bonds may be used alone or in a mixture of two or more. In the present invention, "radiation" includes all radiation sources that generate free radicals and induce addition polymerization of vinyl bonds. Suitable radiation is 200-7500
It has a wavelength of 2000-4000 Å, preferably 2000-4000 Å. The radiation useful here is ultraviolet light. Other forms of radiation include sunlight, artificial light sources such as carbon arc lamps, and mercury vapor lamps. A preferred electron beam system is one in which a linear cathode emits a direct electron curtain. The radiation curable resin composition of the present invention may contain an effective amount of a photosensitizer when photocuring the composition. Essentially, this amount is about 0.01-10%, preferably about 0.1-5% by weight of the resin composition. These photosensitizers and their curing processes are well known in the art. Examples include: For example, benzophenone, benzyl acetophenone, benzyl dimethyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, dimethoxyacetophenone, diethoxyacetophenone, dimethoxyphenylacetophenone, diphenyl enyl disulfide, α-alkylbenzoin, etc. These photosensitizers can also contain synergists, such as tertiary amines, to enhance the conversion of light absorption energy into polymerization-initiating free radicals. When this curable composition is cured by electron beam irradiation, it is not necessarily necessary to add a sensitizer. The resin composition of the present invention may contain various other additives such as thermal polymerization inhibitors, surfactants, ultraviolet absorbers, matting agents, thixotropic agents, dyes, and pigments, as desired. Furthermore, various thermoplastic resins, thermosetting resins, etc. can also be blended. The compositions of the present invention can be cured by applying them as a thin film onto a substrate. As a method for forming a thin film, spraying, brushing, dipping, roll coating, etc. are used. Although curing is preferably carried out under an inert gas (for example, nitrogen gas) atmosphere, it can also be cured under an air atmosphere. The cured composition according to the present invention can be used in various coating fields such as ink, plastic paint, paper stamping, film coating, metal coating, furniture painting, FRP, lining, as well as insulating varnish, insulating sheet, laminated sheet, and laminated material in the electronics field. It can be applied to many industrial fields such as boards, printed circuit boards, resist inks, and semiconductor encapsulants. The present invention will be explained in more detail in the following examples. In the examples, parts represent parts by weight. Synthesis Example-1 7308 parts (28.0 mol) of tris(2-hydroxyethyl)isocyanurate and 3192 parts (28.0 mol) of ε-caprolactone were placed in a 4-necked flask equipped with a nitrogen inlet tube, thermometer, cooling tube, and stirring device. , 0.105 parts of tetrabutyl titanate was added as a catalyst,
When the reaction was carried out at 170° C. for about 7 hours in a nitrogen atmosphere, the amount of unreacted ε-caprolactone was 0.6% or less. 375 parts (1.0 mol) of the obtained lactone-modified tris(2-hydroxyethyl)isocyanurate, 360 parts (5.0 mol) of acrylic acid, 3.7 parts of para-toluenesulfonic acid as a catalyst, 200 parts of benzene as an azeotropic dehydration solvent, and hydroquinone monomethyl ether
0.7 part was placed in a flask and dehydration reaction was carried out under benzene reflux. The reaction was terminated when water stopped distilling out. After completion of the reaction, acrylic acid was removed by washing with a benzene/water system, and then benzene was removed under reduced pressure to obtain an acrylate resin having the following properties. Appearance Yellow-brown liquid Viscosity (25℃) 4760 CP Acid value 0.2 Synthesis Example-2 261 parts (1.0 mol) of tris(2-hydroxyethyl)isocyanurate was prepared in the same manner as Synthesis Example-1.
was reacted with 342 parts (3.0 mol) of ε-caprolactone, and then 603 parts (1.0 mol) of the obtained lactone-modified tris(2-hydroxyethyl)isocyanurate was reacted with 360 parts (5.0 mol) of acrylic acid to obtain the following properties. acrylate resin was obtained. Appearance Yellow-brown liquid Viscosity (25°C) 2260 CP Acid value 0.3 Examples 1 to 2 90 parts of acrylate resin obtained in Synthesis Example-1 and Synthesis Example-2, 10 parts of styrene, benzyl dimethyl ketal (Ciba Gaiki Co., Ltd. Irgakiyure 651) 2
The mixture was mixed and coated on an iron substrate to a thickness of 15 μm, and cured 10 cm under a high-pressure mercury lamp (output 80 W/cm) at a belt speed of 2 m/mm, and the physical properties of the coating film were evaluated. Comparative Example 1 Evaluation was carried out in the same manner as in Example 1 except that the acrylate resin was replaced with tris (2-hydroxyethyl) isocyanurate (Toagosei Aronix M-315). The results are summarized in Table-1.

[Table] Measurement Examples 3 and 4 Comparison 2 Resin was injected between two glass plates using silicone rubber as a spacer with the same formulation as in Examples 1 and 2 and Comparative Example 1, and the resin was placed 10 cm under a high-pressure mercury lamp.
Irradiate the area 5 times on each side at a speed of 2 m/min to form a 4 mm
A resin plate having a thickness of 100 mL was prepared, and the heat distortion temperature was measured based on JIS K-7207. The results are shown in Table-2.

[Table] Examples 5 and 6 Comparative Example 3 Acrylate resin and tris(2-hydroxyethyl) isocyanurate obtained in Synthesis Example-1 and Synthesis Example-2 (Toagosei Aronix M-315)
The same evaluation as in Example 1 was carried out by blending 70 parts of 1,6-hexanediol diacrylate, 10 parts of N-vinylpyronidone, and 3 parts of benzoin isobutyl ether as a photoinitiator.
The results are shown in Table-3.

[Table] Example 7 20 parts of toluene was added to 80 parts of the acrylate resin obtained in Synthesis Example-1, and Irgakiure was added as a photoinitiator.
Add 3 parts of 651 (Ciba Geigy) and place it on the iron board.
Apply the film to a thickness of 15 μm, heat it at 80°C for 20 minutes to remove toluene, and place it 10 cm under a high-pressure mercury lamp (80 W/cm) at belt speed 2.
It was cured by passing at m/min. Comparative Example 4 Tris [acryloyltri(oxyethylene)] was used instead of the acrylate resin obtained in Synthesis Example-1.
The same procedure as Example 7 was carried out except that isocyanurate was used. The flexibility and appearance of the cured coating films obtained in Comparative Example 4 and Example 7 were compared immediately after curing and after being maintained at 100°C for 72 hours. Flexibility was measured based on JIS K5400. The results are shown in Table 4.

[Table] From the results shown in Table 4, it is clear that even among acrylates having the same isocyanurate skeleton, those having a polyester structure are superior in heat resistance to acrylates having a polyoxyalkylene structure. From the above results, it is clear that the cured product obtained using the resin composition of the present invention has improved flexibility without impairing heat resistance.

Claims (1)

[Claims] 1. (A) 15 to 100 parts by weight of an acrylate resin or methacrylate resin represented by the general formula () 《However, in the formula, L ¹ is , L ² is , L ³ is represents. n1, n2, and n3 are each 0 or a positive integer from 1 to 10, and n1, n2, and n3 cannot be 0 at the same time. R ¹ , R ² and R ³ represent -H, [Formula] or [Formula], and R ¹ , R ² and R ³ cannot be -H at the same time. 》 and (B) vinyl compound with ethylenically unsaturated bond
A curable resin composition comprising 85 to 0 parts by weight and (C) a photoinitiator in an amount of 0.01 to 10% by weight based on the total weight of (A) and (B).