JP2006008729A - Photocurable resin composition and method for producing cured product thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a photocurable resin composition having excellent surface hardness, high bonding strength, moisture resistance and color fastness. <P>SOLUTION: The photocurable resin composition comprises (1) a hydrogenated bisphenol A type diglycidyl ether compound, (2) a reactive diluent containing one or more epoxy groups in one molecule and (3) a cationic photopolymerization initiator. Preferably (1) the photocurable resin composition has ≥99% hydrogenation ratio of the hydrogenated bisphenol A type diglycidyl ether compound, (2) the photocurable resin composition comprises the reactive diluent containing one or more epoxy groups in one molecule, which is epoxycyclohexane or pinene oxide and the curable resin composition contains further (4) a silane coupling agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a photocurable resin composition that has good surface curability, high adhesion strength and moisture resistance, and can provide a non-yellowing cured product, and a method for producing the cured product.

In the recent optoelectronics field, demands for adhesives having higher adhesiveness and moisture resistance are increasing with the improvement in performance of devices.

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 it is necessary to consider nitrogen substitution during curing for the purpose of curing the surface well.

Moreover, as a curable resin composition having good surface curing, Patent Document 1 proposes a curable resin composition using polyene and polythiol as raw materials. However, since the glass transition temperature of this type of curable resin is generally less than 20 ° C., there is a problem that high adhesive strength cannot be obtained. Furthermore, when a cured resin such as an adhesive is used in the vicinity of its glass transition temperature, the mechanical properties of the cured resin may change significantly due to slight temperature changes, causing problems such as a decrease in adhesive strength. .
Japanese Examined Patent Publication No. 63-002055.

Epoxy resin compounds using photocations as catalysts are also known, but they have a high glass transition point and good surface curability, but change color after high temperature and high humidity conditions (pressure cooker test, hereinafter abbreviated as “PCT”). There was a problem.

The above-mentioned discoloration phenomenon is a big problem because, for example, when it is used as a member such as an adhesive for an optoelectronic component such as a short wavelength LED or an optical fiber, the light transmittance is reduced.

In addition, Patent Document 2 discloses an epoxy resin containing an epoxy compound having a naphthalene skeleton as an active ingredient and evaluates light transmittance in an infrared region having a wavelength of 1300 nm. Is not mentioned.
Japanese Patent Application Laid-Open No. 2004-010676.

An object of the present invention is to provide a one-component photocurable resin composition having good surface curability, high adhesive strength and moisture resistance, and less discoloration. Here, about high adhesive strength, it is making it the subject to obtain the thing of high adhesive strength of 7 Mpa or more.

The present invention includes (1) a hydrogenated bisphenol A type diglycidyl ether compound, (2) a reactive diluent having one or more epoxy groups in one molecule, and (3) a photocationic polymerization initiator. Preferably, (1) the hydrogenation rate of the hydrogenated bisphenol A type diglycidyl ether compound is 99% or more. The photocurable resin composition according to the above, wherein (2) the reactive diluent having one or more epoxy groups in one molecule is epoxycyclohexane or pinene oxide. And (4) the photocurable resin composition described above, further comprising a silane coupling agent.

The present invention also relates to (1) a hydrogenated bisphenol A type diglycidyl ether compound, (2) a reactive diluent having one or more epoxy groups in one molecule, and (3) initiation of photocationic polymerization. And (4) a photocurable resin composition containing a silane coupling agent, and a cured product having a tensile shear bond strength of less than 7 MPa is obtained at 121 ° C. under 2.1 atm. Pressure and 100% relative humidity for 48 hours. By processing, it is a manufacturing method of the photocurable resin composition hardening body characterized by making tensile shearing adhesive strength 7 MPa or more.

Since the photocurable resin composition of the present invention provides a cured product having high adhesive strength, excellent moisture resistance, and excellent discoloration resistance, it can be bonded in the optoelectronic field such as short wavelength LEDs and optical fibers. It is useful as a member such as an agent.

Further, according to the method for producing a cured product of the photocurable resin composition of the present invention, it is possible to stably provide a cured product having a high tensile shear adhesive strength of 7 MPa or more and excellent in moisture resistance and discoloration resistance. is there.

(1) As a hydrogenated bisphenol A type diglycidyl ether compound (hereinafter simply referred to as component 1), for example, “YX-8000” (see (Chemical Formula 1)) or “YX-8300” manufactured by Japan Epoxy Resin Co., Ltd. Etc. Component 1 does not have an aromatic ring in the molecule as compared with other aromatic epoxies, so it is effective not only for preventing troubles such as discoloration, but also has a high polymerization reaction rate in photocationic polymerization. It is preferable in terms of productivity. In the present invention, the proportion of hydrogenation is preferably 99 mol% or more, based on the total amount of hydrogen that can be added to the aromatic ring. If it is less than 99 mol%, the cured product may be discolored or the curing reaction rate may be slow.

In the present invention, (2) a reactive diluent having one or more epoxy groups in one molecule (hereinafter referred to as component 2) contains one or more epoxy groups in one molecule, Any material may be used as long as it satisfies the moisture resistance and discoloration resistance along the line, but based on the experimental study by the present inventors, epoxycyclohexane (see (Chemical Formula 2)), α-pinene oxide ( (See Chemical Formula 3)) or 2,3-epoxynorbornane is preferably selected.

The amount of the reactive diluent is determined by the desired adhesive viscosity, but is usually about 1 to 40% by mass, preferably about 5 to 30% by mass, based on the total of Component 1 and Component 2. The If the reactive diluent is too much, the viscosity is lowered, and if it is too little, the viscosity is increased. Moreover, when there is much quantity, it will cause a curing defect and a use may be limited.

(3) As the photocationic polymerization initiator (hereinafter referred to as component 3), aromatic sulfonium salts, aromatic iodonium salts, aromatic sulfoxonium salts, and compounds thereof are preferable, and in particular, aromatic iodonium hexa A fluorophosphonate compound is preferred from the viewpoints of curability, adhesiveness, and outgas. These polymerization initiators can be used alone or in combination of two or more. The compounding quantity of a polymerization initiator is 0.001-10 mass parts with respect to 100 mass parts of total amounts of the component 1 and the component 2, Preferably it is 0.1-3 mass parts.

Examples of the polymerization initiator include Ciba Geigy's Irgacure 250 (see (Chemical Formula 4)). In this case, the blending amount is the total amount of Component 1 and Component 2, that is, the total amount of resin 100 It is used in the range of 0.5 to 5 parts by mass, preferably 1 to 3 parts by mass with respect to parts by mass. If it exceeds 5 parts by mass, the curing reaction rate may be too fast, and if it is less than 0.5 parts by mass, the curing reaction may be slow, and in either case, it may not be practical.

When the component 1, the component 2, and the component 3 are blended, the resin composition is cured by light having a wavelength of 250 nm, and the obtained cured body strongly bonds the glasses and exhibits high adhesive strength. Moreover, even when exposed to high-temperature and high-humidity conditions at 121 ° C. and 0.12 MPa 100% RH, the adhesive strength does not deteriorate and does not discolor, and is useful as a member such as an adhesive in the optoelectronic field. .

In the present invention, a photosensitizer can be used for the purpose of accelerating the curing reaction. As a photosensitizer, an aromatic ketone compound may be mixed. Examples of such an aromatic ketone compound include Ciba Geigy's Darocur 1173 (see (Chemical Formula 5)).

The amount of the photosensitizer is about a half of the photoinitiator, and is preferably in the range of 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the resin.

In the present invention, a silane coupling agent can be further contained. The silane coupling agent is involved in the bond between inorganic and organic, silane alkoxylate acts on the inorganic, and glycidyl group or amino group acts on the organic. In the present invention, γ-glycidoxypropyltrimethoxyxysilane (“A-187” manufactured by Nippon Unica Co., Ltd.) (see (Chemical Formula 6)) is preferably selected.

In the present invention, in particular, when a bisphenol A type diglycidyl ether compound hydrogenated 99% or more is used as component 1, when using epoxycyclohexane or pinene oxide as component 2, further containing a silane coupling agent When the resin composition is cured, the resin composition is cured by light having a wavelength of 250 nm, and the resulting cured product exhibits high adhesive strength by firmly bonding the glasses to each other, and at a high temperature and high humidity of 121 ° C. and 0.12 MPa 100% RH. It has a remarkable property that the adhesive strength does not deteriorate even when exposed to conditions, and is less likely to discolor, and is suitable as a member such as an adhesive in the optoelectronic field such as a short wavelength LED or an optical fiber.

In addition, the photocurable resin composition of the present invention includes one or more fillers, antioxidants, dyes, fillers, pigments, thixotropy imparting agents, plasticizers, surfactants, lubricants, and antistatic agents as necessary. Additives such as agents can be added.

Further, the present inventor has (1) a hydrogenated bisphenol A type diglycidyl ether compound, (2) a reactive diluent having one or more epoxy groups in one molecule, and (3) a photocationic polymerization. Regarding a photocurable resin composition containing an initiator and (4) a silane coupling agent, even if the tensile shear bond strength of the cured product after photocuring is less than 7 MPa, it is exposed to specific environmental conditions. Sometimes, it was found that the tensile shear bond strength can be modified to 7 MPa or more, and the present invention has been achieved.

According to the present invention, a cured product having a tensile shear bond strength of 7 MPa or more, excellent moisture resistance and hardly discoloring can be stably obtained, so that in the field of optoelectronics such as short wavelength LEDs and optical fibers. It is extremely useful as a member such as an adhesive.

(Examples 1-5, Comparative Examples 1 and 2) Each substance was mixed at the ratio shown in Table 1 to prepare various photocurable resin compositions, cured under the following photocuring conditions, and tensile sheared. The bond strength, glass transition temperature, and surface curability were examined. Furthermore, after exposing the cured body for 48 hours under the condition of 121 ° C. and 0.12 MPa 100% RH, appearance inspection, stickiness, and discoloration were evaluated, and tensile shear bond strength was evaluated (PCT test). Here, as an appearance inspection, the transmittance at a wavelength of 300 nm was measured using a spectrophotometer UV-1600 (manufactured by Shimadzu Corporation) for the purpose of quantitatively evaluating the degree of discoloration.

(Photo-curing conditions) Upon photo-curing, curing was performed under a condition of an integrated light amount of 4000 mJ / cm ^{2 having} a wavelength of 250 nm by a curing apparatus manufactured by Fusion Corporation using an H plus electrodeless discharge lamp.

(Tensile shear bond strength) A photo-curable resin composition in which a glass test piece (“Pyrex (registered trademark)” heat-resistant glass having a size of 25 × 25 × 2 mm) has an adhesive area of 12.5 mm × 25 mm. Was applied and cured under the photocuring conditions. Sand blasting is applied to the opposite side of the glass test piece from the bonding surface, and iron blasting (100 x 25 x 1.6 mm) prepared separately is also sand blasted, and the iron test is performed with a photocurable resin composition. The specimen and the blasted surface (25 mm × 25 mm) of the glass test piece were bonded to obtain a test body for measuring the tensile shear bond strength of an area of 12.5 mm × 25 mm. The test body was fixed with an axial center aligning plate (thickness 3.6 mm) in both the upper and lower sides and measured. Further, the tensile shear adhesive strength (unit: MPa) was measured under the conditions of a temperature of 23 ° C. and a humidity of 50% under a tensile speed of 10 mm / min. Further, the number of repeated experiments was 5, and the average value was used as the result.

Since the photocurable resin composition of the present invention provides a cured product having high adhesive strength, excellent moisture resistance, and excellent discoloration resistance, it can be bonded in the optoelectronic field such as short wavelength LEDs and optical fibers. It is useful as a member such as an agent. In particular, since a cured product with little light absorption at a wavelength of 300 nm can be obtained even when exposed to harsh conditions, it is suitable as a member such as an adhesive for short wavelength LED applications.

Further, according to the method for producing a cured product of the photocurable resin composition of the present invention, it is possible to stably provide a cured product having a high tensile shear adhesive strength of 7 MPa or more and excellent in moisture resistance and discoloration resistance. is there.

Claims (5)

(1) containing a hydrogenated bisphenol A-type diglycidyl ether compound, (2) a reactive diluent having one or more epoxy groups in one molecule, and (3) a photocationic polymerization initiator. A photocurable resin composition characterized by the above. (1) The photocurable resin composition according to claim 1, wherein the hydrogenated ratio of the hydrogenated bisphenol A type diglycidyl ether compound is 99% or more. (2) The photocurable resin composition according to claim 1 or 2, wherein the reactive diluent having one or more epoxy groups in one molecule is epoxycyclohexane or pinene oxide. Furthermore, (4) the silane coupling agent is contained, The photocurable resin composition of Claim 1, Claim 2 or Claim 3 characterized by the above-mentioned. (1) a hydrogenated bisphenol A type diglycidyl ether compound, (2) a reactive diluent having one or more epoxy groups in one molecule, (3) a photocationic polymerization initiator, and (4) A cured product composed of a photo-curable resin composition containing a silane coupling agent and having a tensile shear bond strength of less than 7 MPa is subjected to tensile treatment by treating it at 121 ° C. under 2.1 atm and 100% relative humidity for 48 hours. A method for producing a cured product of a photocurable resin composition, wherein the shear bond strength is 7 MPa or more.