JP4789407B2 - Photocurable resin composition - Google Patents

Description

The present invention relates to a photocurable resin composition. More specifically, the present invention relates to a one-part photocurable resin composition having good surface curability and high adhesive strength.

In the field of optoelectronics in recent years, the demand for an adhesive having higher adhesiveness has been increased with the improvement in performance of equipment. In general, a composition mainly composed of an acrylic raw material is known as a photocurable composition capable of obtaining high adhesive strength. Acrylic photocurable resin compositions are known to be inhibited by oxygen in the air, and considerations such as nitrogen substitution at the time of curing are necessary for the purpose of satisfactorily curing the surface.

On the other hand, as a curable resin composition having good surface curing, a curable resin composition using polyene or polythiol as a raw material has been proposed in Patent Document 1 or the like. Generally, this type of curable resin glass is used. Since the transition temperature is less than 20 ° C., there is a problem that high adhesive strength cannot be obtained. In general, when a cured resin such as an adhesive is used near its glass transition temperature, the mechanical properties of the cured resin may change significantly due to slight temperature changes, causing problems. Has also become an issue.
Japanese Patent Publication No. 63-20255.

The subject of this invention is providing the photocurable resin composition from which high adhesive strength is acquired because surface curability is favorable and glass transition temperature is more than a practical temperature atmosphere.

The present invention relates to a component a comprising a compound having two or more allyl groups (—CH ₂ —CH═CH ₂ ) in one molecule, and a compound having two or more mercapto groups (—SH) in one molecule. Component b, a component c composed of a compound having two or more (meth) acryloyl groups in one molecule, and a component d composed of a photopolymerization initiator, the content of component c being component a, component b, in a total amount by weight ratio to the 90: 10 from Ri range der 30:70, the 1 molecule component a composed of a compound having two or more allyl groups in the one or allyl alcohol derivative Component b, which is a combination of two or more types and is composed of a compound having two or more mercapto groups (-SH) in one molecule, is represented by the general formula A- (SH) q (where A is q SH groups). Is an organic residue to which q is attached, q is 2 or more Component c consisting of a compound having two or more (meth) acryloyl groups in one molecule,
Formula _{B- (O- (C = O)} -CH 2 = CH 2) r or
Formula B- (O- (C = O) -CH (-CH 3) = CH 2) r
Where B is an organic residue to which r (meth) acryl groups are bonded, and r is an integer of 2 or more . It is an adhesive composition, and preferably a cured product of the above-mentioned photocurable adhesive composition, wherein the glass transition temperature is 35 ° C. or higher.

Since the photocurable resin composition of the present invention is cured without being affected by oxygen and has high adhesive strength, it is an adhesive composition applicable in the field of optoelectronics.

The component a consisting of a compound having two or more allyl groups (—CH ₂ —CH═CH ₂ ) in one molecule used in the present invention includes allyl alcohol derivatives.

Examples of allyl alcohol derivatives include triallyl isocyanurate, triallyl cyanurate, diallyl malate, diallyl fumarate, diallyl adipate, diallyl phthalate, triallyl trimellitate, tetraallyl pyromellitate, glyceryl diallyl ether, trimethylolpropane diallyl Examples include ether, pentaerythritol diallyl ether, sorbitol diallyl ether, and the like, and these can be used alone or in combination.

Component b comprising a compound having two or more mercapto groups (—SH) in one molecule used in the present invention includes esters of mercaptocarboxylic acid and polyhydric alcohol, aliphatic polythiols and aromatic polythiols, Other examples include polythiols. These 1 type (s) or 2 or more types can be used.

Among the esters of mercaptocarboxylic acid and polyhydric alcohol, examples of mercaptocarboxylic acid include thioglycolic acid, α-mercaptopropionic acid, and β-mercaptopropionic acid.

Among the esters of mercaptocarboxylic acid and polyhydric alcohol, polyhydric alcohols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol and Examples include sorbitol and tris-2hydroxyethyl isocyanurate.

Aliphatic polythiols and aromatic polythiols include ethanedithiol, propanedithiol, hexamethylenedithiol, decamethylenedithiol, tolylene-2,4-dithiol and xylenedithiol.

Other polythiols include diglycol dimercaptan, triglycol dimercaptan, polyoxypropylene glycol dimercaptan, and the like.

In the photocurable resin composition of the present invention, component a comprising a compound having two or more allyl groups (—CH ₂ —CH═CH ₂ ) in one molecule and two or more mercapto groups in one molecule The blending ratio with the component b composed of the compound having (—SH) is preferably in the range of 5: 1 to 1: 5 in terms of a molar ratio of the double bond of the component a and the mercapto group of the component b. Is more preferable.

Component c comprising a (meth) acrylic monomer having two or more reactive unsaturated double bonds in one molecule used in the present invention includes ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene Glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, dicyclopentenyl di (meth) acrylate, isocyanuric acid EO modified di (meth) acrylate, isocyanuric acid EO modified tri ( (Meth) acrylate, EO-modified bisphenol A di (meth) acrylate, 1,4 butanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaeryth Toruhekisa (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, neopentyl glycol di (meth) acrylate.

In the photocurable resin composition of the present invention, the content of the component c composed of a compound having two or more (meth) acryloyl groups in one molecule is two or more allyl groups (—CH _{2 in} one molecule). From 90:10 by mass ratio to the total amount of component a consisting of a compound having —CH═CH ₂ ) and component b consisting of a compound having two or more mercapto groups (—SH) in one molecule. A range of 30:70 is preferable, and a range of 80:20 to 40:60 is more preferable.

The photocurable resin composition of the present invention is a component a composed of a compound having two or more allyl groups (—CH ₂ —CH═CH ₂ ) in one molecule, and two or more mercapto groups in one molecule ( A component b consisting of a compound having -SH), a component c consisting of a (meth) acryl monomer having two or more reactive unsaturated double bonds in the molecule, and a component d consisting of a photopolymerization initiator are essential. (Meth) acrylate monomer having one reactive unsaturated double bond in one molecule under the condition that the glass transition temperature of the cured resin is 35 ° C. or higher. It is possible to use reactive diluents.

Component d comprising the photopolymerization initiator used in the present invention is blended for sensitization with active light such as ultraviolet rays and visible light to promote photocuring of the resin composition, and various known photopolymerization starts. The agent can be used. Specifically, 1-hydroxycyclohexyl phenyl ketone, benzophenone, p-methoxybenzophenone, acetophenone, propiophenone, thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, benzoin Methyl ether, benzoin ethyl ether, p-chlorobenzophenone, 4-benzoyl-4-methyldiphenyl sulfide, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1 [ 4- (methylthio) phenyl] -2-morpholinopropanone-1 and the like can be exemplified.

These photopolymerization initiators can be used alone or in combination of two or more. The compounding quantity of a polymerization initiator is 0.001-20 mass parts with respect to 100 mass parts of total amounts of the component a, the component b, and the component c, Preferably it is 0.1-15 mass parts.

In addition, the photocurable resin composition of the present invention can be used, if necessary, as an adhesion improver such as a silane coupling agent or an acidic phosphate ester, an antioxidant, a curing accelerator, a dye, a filler, a pigment, a thixotropy. Additives such as an imparting agent, a plasticizer, a surfactant, a lubricant, and an antistatic agent can be added.

Component a consisting of a compound having two or more allyl groups (—CH ₂ —CH═CH ₂ ) in one molecule in the present invention, consisting of a compound having two or more mercapto groups (—SH) in one molecule The mixture of component b can be pre-reacted and used as a prepolymer. As a method of producing a prepolymer by reacting in advance, a method of simply heating a mixture of component a and component b, a method of heating by adding a small amount of an organic peroxide, etc., a component comprising a small amount of a photopolymerization initiator Examples of the method include adding d and irradiating ultraviolet rays, and the method of simply heating the mixture of component a and component b is preferable from the viewpoint of controlling the reaction rate. The reaction temperature is preferably 5 to 70 ° C. from the viewpoint of controlling the reaction rate.

In addition, a component a composed of a compound having two or more allyl groups (—CH ₂ —CH═CH ₂ ) in one molecule that is usually commercially available, and two or more mercapto groups (—SH) in one molecule. The component b consisting of the compound having 1 and the component c consisting of the compound having two or more (meth) acryloyl groups in one molecule usually contain impurities, and these impurities are converted into chelate compounds and removed. This makes it easier to control the reaction rate.

Hereinafter, the present invention will be described with reference to experimental examples. The unit of the amount used of each substance is shown in parts by mass. Various physical properties were measured as follows.

[Photo-curing conditions] In photo-curing, curing was performed under a condition of an integrated light quantity of 2000 mJ / cm ² at a wavelength of 365 nm by a curing apparatus manufactured by Fusion Corporation using an electrodeless discharge lamp.

[Measurement of Glass Transition Temperature] The photocurable resin composition is sandwiched and cured between a 1 mm thick silicon sheet and a PET film to produce a 1 mm thick cured resin. The prepared cured resin was cut into a length of 50 mm and a width of 5 mm with a cutter to obtain a cured resin for measuring a glass transition temperature. The obtained cured resin was measured with a dynamic viscoelasticity measuring device DMS210, manufactured by Seiko Denshi Kogyo Co., Ltd., in a nitrogen atmosphere at a temperature rising rate of 2 ° C. per minute. I read as.

[Shear bond strength] A hole having a diameter of 8 mm is made with a ball plate at a position about 12 mm from one end of one aluminum test piece (100 mm x 25 mm x 2.0 mm, A-5052 material). A glass test piece (25 mm × 25 mm × 2 mm Pyrex heat-resistant glass) is fixed so as to cover one side of an 8 mm hole, a photocurable resin composition (hereinafter also simply referred to as an adhesive) is applied in the hole, and the above The adhesive is cured under conditions. After curing, another aluminum test piece was bonded to the back surface of the glass with a commercially available room temperature curing adhesive to obtain a test piece. The tensile shear bond strength (unit: MPa) was measured at a tensile rate of 10 mm / min in an environment of a temperature of 23 ° C. and a humidity of 50%.

[Surface Curability] About 1 gram of the adhesive was dropped into the polycap, cured in the air under the above conditions, and evaluated by finger touch. The evaluation at this time is as follows.
○: No tack △: Degree of fingerprints ×: Uncured surface

(Experimental example 1) Each substance was mixed with the usage-amount of Table 1, and the photocurable composition was prepared. This was evaluated for shear bond strength, glass transition temperature and surface curability. The results are also shown in Table 1. Moreover, Nippon Unica Co., Ltd. A-174 was used for the silane coupling agent in a compounding composition.

(Experimental example 2) It carried out like Experimental example 1 except having mixed each substance with the usage-amount of Table 2, and preparing the photocurable adhesive composition. The results are shown in Table 2.

Since the photocurable resin composition of the present invention is cured without being affected by oxygen and has a high adhesive strength, an adhesive applicable in the field of optoelectronics is provided.

Claims (2)

Component a consisting of a compound having two or more allyl groups (—CH ₂ —CH═CH ₂ ) in one molecule, component b consisting of a compound having two or more mercapto groups (—SH) in one molecule, It contains a component c composed of a compound having two or more (meth) acryloyl groups in one molecule, and a component d composed of a photopolymerization initiator, and the content of the component c is between the component a and the component b. The mass ratio with respect to the total amount is in the range of 90:10 to 30:70,
Component a consisting of a compound having two or more allyl groups in one molecule is triallyl isocyanurate or diallyl malate ,
Component b comprising a compound having two or more mercapto groups (—SH) in one molecule is tris-2hydroxyethyl-isocyanurate tris-βmercaptopropionate or trimethylolpropane-tris-β-mercapto. Propionate ,
The component c consisting of a compound having two or more (meth) acryloyl groups in one molecule is isocyanuric acid EO-modified tri (meth) acrylate or pentaerythritol tri (meth) acrylate . Adhesive composition. The cured product of the photocurable adhesive composition according to claim 1, wherein the glass transition temperature is 35 ° C. or higher.