JPH03166219A - Ultraviolet ray-curing type resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition useful as adhesive and coating material capable of curing at low temperature and after curing at a constant temperature having a short curing time containing cationic ultraviolet rays- polymerization initiator and specific compound in epoxy resin in a specific ratio. CONSTITUTION:100 pts.wt. epoxy resin (e.g. alicyclic epoxy resin) is mixed with 0.5-10 pts.wt. cationic ultraviolet rays-polymerization initiator (e.g. p- chlorobenzenediazonium hexafluorophosphate) and 0.5-30 pts.wt. a compound having ethylenic unsaturated group and hydroxyl group within a same molecule [e.g. 2-hydroxyethyl (meth)acrylate] to afford the aimed composition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an epoxy resin composition that is cured by irradiation with ultraviolet rays, and is particularly useful as an adhesive or a coating agent.

BACKGROUND ART In recent years, methods of curing resins by irradiating them with ultraviolet rays have been used in various fields. Various types of ultraviolet curable resin compositions and ultraviolet curable resins are known.
To give an example, a resin composition containing urethane (meth)acrylate and an acrylate monomer disclosed in JP-A-57-172915, and JP-A-62-3
There is an epoxy (meth)acrylate resin disclosed in Japanese Patent No. 33651, and it is also known that various epoxy resins can be cured with ultraviolet polymerization initiators such as aromatic diazonium salts.

Is the curing method using UV irradiation the heat curing method? Compared to the previous method, ■curing time is short, ■can be cured at a certain lower temperature than conventional methods, ■does not require solvent or only requires a small amount of solvent, so it saves resources and causes less environmental pollution, etc. It has the following advantages.

<Problems to be Solved by the Invention> The present inventors have mainly studied ultraviolet curable resin compositions useful as adhesives and coating agents for glass as an adherend.

In the process, we investigated known ultraviolet curable resin compositions and ultraviolet curable resins, and found that ultraviolet curable resin compositions containing urethane (meth)acrylate resins and epoxy (meth)acrylate resins have no effect on glass. Adhesion was insufficient, and ultraviolet curable resin compositions containing epoxy resins were not sufficiently cured by ultraviolet rays alone due to the presence of unreacted groups in the resin.

Therefore, in order to eliminate these remaining unreacted groups, heating was performed by after-curing to ensure complete reaction, but since this heating temperature was as high as 120°C, it was desired to lower the temperature. The present invention has been made in view of the above-mentioned facts, and aims to provide an ultraviolet curable resin composition that has excellent ultraviolet curability and postcurability by low-temperature heating during after-curing.

Means for Solving the Problems> The present invention is based on 100 parts by weight of an epoxy resin, 0.5 to 10 parts by weight of a cationic ultraviolet polymerization initiator, and a compound having an ethylenically unsaturated group and a hydroxyl group in the same molecule. 0.
The present invention provides an ultraviolet curable resin composition characterized by containing 5 to 30 parts by weight.

The present invention will be explained in detail below.

The ultraviolet curable resin composition of the present invention comprises an epoxy resin,
It contains a cationic ultraviolet polymerization initiator and a compound having an ethylenically unsaturated group and a hydroxyl group in the same molecule.

The epoxy resin used in the present invention may be any commonly used epoxy resin. Examples include alicyclic epoxy resin, bisphenol, A type epoxy resin, novolac type epoxy resin, brominated epoxy resin, bisphenol F type epoxy resin, and the like.

The alicyclic epoxy resin used in the present invention is a compound that has an alicyclic group in its molecule, and a portion of the alicyclic group is epoxidized.

That is, it is a compound having a cyclohexene oxide group, a tricyclodecene oxide group, a cyclopentene oxide group, etc., and specifically, vinylcyclohexene diepoxide, vinylcyclohexene monoepoxide, 3.4-epoxycyclohexylmethyl-3.4- Epoxycyclohexane carboxylate (ERL-4221, manufactured by Union Carbide) 2-(3.4-epoxycyclohexyl-5.5-subillow 3.4-epoxy)cyclohexane-m-dioxane (ERL-4234, Union Carbide) (manufactured by Union Carbide), bis(3,4-epoxycyclohexyl)adivate (ERL-4299, manufactured by Union Carbide), and the like.

Alicyclic epoxy resins are characterized in that they are easily cured by ultraviolet polymerization initiators and can be cured in a short time with low energy.

The bisphenol A epoxy resin used in the present invention is
It refers to a compound represented by the following general formula (I) synthesized from bisphenol A and epichlorohydrin, and a compound represented by the following general formula (II) synthesized from bisphenol A and β-methylepichlorohydrin.

Specific examples include Epicron 850S (manufactured by Inu Nippon Ink Chemical Co., Ltd.), Sumiepoxy ESAO 1 1 (manufactured by Sumitomo Chemical Co., Ltd.), and Epicort 828 (manufactured by Yuka Shell Epoxy Co., Ltd.), but there are many different types. It has been known.

Although bisphenol A type epoxy resin requires slightly high energy for curing by irradiation with ultraviolet rays, it is characterized by excellent adhesion to glass.

Novolak-type epoxy resin is a resin obtained by reacting novolac resin with shrimp chlorohydrin to convert it into glycidyl ether. It is represented by the following general formula (II1).

(n≦2, R=H, or CH3) (III) When R=H, it is a phenol novolac type, and R=
When C H s, it is an orthocresol novolac type.

The brominated epoxy resin is derived from tetrabromobinuphenol A and has a structure as shown in monodentate formula (IV) below.

In addition, bisphenol F type epoxy resin is produced by reacting bisphenol F with shrimp chlorohydrin, and has the following general formula (V). It has a unique structure.

Further, the cationic ultraviolet polymerization initiator used in the present invention refers to aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, aromatic selenium salts, and the like.

All of these ultraviolet polymerization initiators are decomposed by ultraviolet light and release Lewis acids, which polymerize epoxy groups.

Specifically, the cation moiety is, etc., and the corresponding anion is SbF6AsF,-,
PFa-, BF4-, FeC14-, SnCl, SbG
la-, BiCl,' is of the first order.

More specifically, p-chlorobenzenedi7zonium hexafluorophosphate, p-methoxybenzenediazonium hexafluorophosphate, diphenylinoleiodonium hexafluorophosphate, triphenylsulfonium hexafluorophosphate. etc. can be mentioned.

The effective wavelength for decomposing these ultraviolet polymerization initiators varies depending mainly on the chemical structure of the cation, and the curing speed mainly depends on the type of anion and the type of epoxy resin to be cured. Just choose something.

The cationic ultraviolet polymerization initiator is contained in 0.5 to 10 parts by weight per 100 parts by weight of the epoxy resin. 0.5
If the amount is less than 10 parts by weight, the epoxy resin cannot be sufficiently polymerized, and if it exceeds 10 parts by weight, the effect will be saturated, and the curing speed will not improve even if more than 10 parts by weight is added.

Furthermore, the present invention includes a compound having an ethylenically unsaturated group and a hydroxyl group in the same molecule.

A compound having an ethylenically unsaturated group and a hydroxyl group in the same molecule is a compound having one or more ethylenically unsaturated groups capable of radical polymerization and one or more hydroxyl groups capable of chain transfer during cationic polymerization in the same molecule. For example, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, ε-cabrolactone modified 2-
Hydroxyethyl (meth)acrylate, Pentaerythritol tri(meth)acrylate, 2-Hydroxy-
3-phenoxybrobyl (meth)acrylate, 2-hydroxyprobyl (meth)acrylate, 3-acryloyloxyglycerin mono(meth)acrylate, 2-
Hydroxybutyl (meth)acrylate, glycerin di(meth)acrylate, glycerol mono(meth)acrylate, 2-(meth)acryloyloxyethyl-2
-Hydroxyprobyl phthalate, 3-chloro 2-hydroxybrobyl (meth)acrylate, polyethylene glycol (meth)acrylate, polybrobylene zocol mono(meth)acrylate, C}120820CO(:}I-CH2, etc.) .

These compounds are contained in an amount of 0.5 to 30 parts by weight per 10 parts by weight of the epoxy resin.

If it is less than 0.5 part by weight, the chain transfer effect of cationic polymerization will be reduced, making low-temperature after-curing impossible. 3
If the amount exceeds 0 parts by weight, water resistance, adhesive properties, etc., which are characteristics of epoxy resins, will deteriorate.

The ultraviolet curable epoxy resin composition of the present invention contains the above-mentioned components, and in addition, 2-chlorothioxanthone,
2. Photosensitizing aids such as 4-diisobutylthioxanthone, 2,4-dimethylthioxanthone, and penzophenone;
Triethylamine, triethanolamine, 2-dimethylaminoethanol, triphenylphosphine, β~
Photosensitization accelerators such as thiodiglycol, cationic thermal polymerization initiators such as boron trifluoride and sulfonium ion compounds such as CP-66 (manufactured by Asahi Denka), as well as fillers and thickeners. , plasticizers, stabilizers, tackifiers, etc. may be included. Additionally, a small amount of solvent may be included if necessary.

The resin composition of the present invention can be obtained by stirring and mixing its components. Then, store it in a storage room.

The resin composition of the present invention is cured using a mercury lamp, a xenon lamp, a carbon arc, a metal halide lamp, sunlight, etc. as an ultraviolet irradiation source, and a light beam containing ultraviolet rays of 150 to 450 nm is irradiated in the air or in an inert gas atmosphere. You can irradiate it with Preferably the UV intensity is 1-1
0 0 mW/cm'. When irradiating in air, a high-pressure mercury lamp is preferred as the irradiation source.

The resin composite of the present invention can be used as an adhesive or coating agent for various materials.

Example The present invention will be specifically explained based on examples.

(Example) The component compositions shown in Table 1 were heated to 60° C. and melted and mixed to prepare an ultraviolet curable resin composition. Regarding these,
The presence or absence of unreacted groups was examined by measuring compatibility, UV curability (surface tackiness), and DSC peak using the method described below. The results are shown in Table 1.

(Measurement method) (1) After mixing the compatible ultraviolet curable resin compositions, the mixture is allowed to stand at 25°C. Thereafter, it was visually determined whether there was any cloudiness.

■ Curing properties with ultraviolet rays Apply the resin composition to a thickness of 50 μm on the entire 15cmxl 5cm glass plate, and apply ultraviolet rays of 30 mW/cm' with a metal halide lamp to 1000 ml of ultraviolet light.
After curing the resin by irradiating the resin with an energy amount of "mJ/cm", a finger touch test was performed to determine whether there was surface tack. ■Measurement of DSC beak Each resin composition was placed on a glass plate with a thickness of about 50 μm. A cured product was obtained by applying ultraviolet rays with an energy amount of iooomJ/cm2 using a metal halide lamp.Then, this cured product before and after after-curing was subjected to DSC.
(Manufactured by DuPont, Model No. 9 1 0
) was used to measure the presence or absence of reaction heat. Note that the after-cure was performed by holding the sample in an electric oven at 80° C. for 30 minutes.

As shown in Table 1, by adding 0.5 to 30 parts by weight of a compound having an ethylenically unsaturated group and a hydroxyl group in the same molecule to 100 parts by weight of the epoxy resin, the compatibility and surface tack can be improved. Both characteristics were good.

In addition, as an example of the measurement results of the DSC peak in Table 1, FIG. Figure 2 shows the presence or absence of reaction heat before and after after-curing at 80° C. for 30 minutes using a resin composition outside the scope of the present invention (Comparative Example 1). According to this, in the resin composition of the present invention, the heat of reaction generated before after-curing disappeared by after-curing at a low temperature of 80°C, that is, it is clear that no unreacted groups remain. It is.

Effects of the Invention The resin composition of the present invention is cured by irradiation with ultraviolet rays, so it has the advantage of short curing time and can be cured at low temperatures. became possible.

Therefore, it can be effectively used for adhesives and coating materials.

Furthermore, when the resin composition of the present invention is used as an adhesive or coating agent, it does not require a solvent or only requires a small amount of solvent, so it saves resources and prevents environmental pollution. can do.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the presence or absence of reaction heat before and after after-curing the ultraviolet curable resin composition shown in Example 2 of the present invention at 80°C. Figure 2 is a graph measuring the presence or absence of reaction heat before and after after-curing the ultraviolet curable resin composition shown in Comparative Example 1 of the present invention at 80°C.

Claims (1)

[Claims] (1) For 100 parts by weight of epoxy resin, 0.5 to 10 parts by weight of a cationic ultraviolet polymerization initiator and 0.5 to 10 parts by weight of a compound having an ethylenically unsaturated group and a hydroxyl group in the same molecule.
30 parts by weight.