JP4331644B2 - UV curable resin composition - Google Patents

Description

  The present invention is an optical component used in the field of optical communication and a transparent resin used for assembling an optical component, has transparency and excellent adhesive strength for passing an optical signal with low loss, and is suitable for an opto-electric hybrid board or the like. The present invention relates to an ultraviolet curable resin composition having high solder heat resistance reliability and excellent moisture resistance reliability when used. In particular, the present invention relates to an ultraviolet curable resin composition useful as a lens fixing, an optical device package seal, an optical fiber fixing to a V-groove substrate, an optical component material such as an optical waveguide or a lens.

In recent years, not only highly transparent optical adhesives but also optical waveguides using polymer materials have been proposed and put into practical use. Thus, as various optical materials, polymer materials are used because they have various advantages such as easy processing, use in a wide range of applications, and easy adjustment of the refractive index. . In such a situation, for example, a polymer material using a compound having an oxetane ring has been proposed (see Patent Document 1).
JP 2000-356720 A

  However, it cannot be said that the polymer material is sufficient in terms of heat resistance and moisture resistance, and improvement of more excellent characteristics is desired.

  This invention is made | formed in view of such a situation, The objective is to provide the ultraviolet curable resin composition which was excellent in heat resistance and moisture resistance, and excellent in the transmittance | permeability.

（Ｂ）下記の一般式（２）で表される液状エポキシ樹脂。

（Ｃ）光重合開始剤。 In order to achieve the above object, the ultraviolet curable resin composition of the present invention is an ultraviolet curable resin composition containing the following (A) to (C), and the content ratio of the following (A) is: , (A) and (B) in the total amount of 40 to 80% by weight, and the following (B) content is 20 to 60% by weight in the total amount of (A) and (B) It is configured to be set to .
(A) 3-ethyl-3- (phenoxymethyl) oxetane represented by the following structural formula (1).

(B) Liquid epoxy resin represented by the following general formula (2).

(C) Photopolymerization initiator.

That is, the present inventor has intensively studied to obtain an ultraviolet curable resin composition having excellent heat resistance and moisture resistance. Phenyl As a result, the use of a specific amount of the specific oxetane compound (A), the epoxy resin, using a specific amount of the specific the epoxy resin (B), the above specific oxetane compound (A) is a monofunctional compound Since it has a group, the glass transition temperature (Tg) of the cured product is low, and a high molecular weight cured product can be formed. On the other hand, the specific epoxy resin (B) is a fluorinated epoxy resin and has high transparency but low reactivity, and is usually incompatible with oxetane compounds, but the specific oxetane compound ( A) and the specific epoxy resin (B) have good compatibility, and by using both in combination, the heat resistance is remarkably improved and a cured product having good transparency can be obtained. The present invention has been reached by finding that the intended purpose is achieved.

Thus, the present invention is an ultraviolet curable resin composition using specific amounts of the specific oxetane compound (A) and the specific liquid epoxy resin (B). For this reason, it has high transparency, and even when left at a high temperature corresponding to the solder temperature, there is almost no decrease in transmittance, resulting in low loss. Further, even in a severe moisture resistance reliability test such as a pressure cooker test (PCT), it has excellent adhesion without causing peeling. Therefore, the ultraviolet curable resin composition of the present invention is used for adhesion of precision optical parts such as V grooves and optical waveguides (AWG) in optical communication systems and fiber arrays, and as a molding material for optical waveguides and lenses. Thus, a highly reliable optical system can be obtained.

Further, when a specific amount of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is used in addition to the above components, the compatibility between the specific oxetane compound (A) and the specific epoxy resin (B) is increased. A uniform and more transparent cured product can be obtained.

  The ultraviolet curable resin composition of the present invention can be obtained by using a specific oxetane compound (A), a specific liquid epoxy resin (B), and a photopolymerization initiator (C).

  The specific oxetane compound (A) is 3-ethyl-3- (phenoxymethyl) oxetane represented by the following structural formula (1).

  Examples of 3-ethyl-3- (phenoxymethyl) oxetane represented by the structural formula (1) include OXT-211 manufactured by Toagosei Co., Ltd.

The content ratio of 3-ethyl-3- (phenoxymethyl) oxetane (A) represented by the structural formula (1) is 40% of the total amount of the specific oxetane compound (A) and the specific epoxy resin (B). It is necessary to set it to be in the range of ˜80% by weight. Particularly preferred is 50 to 70% by weight. At below 40% by weight, it is difficult to obtain sufficient curability, it exceeds 80 wt%, physical properties of the cured product volatile component amount of unreacted increase is Luke et be reduced.

  The specific liquid epoxy resin (B) used together with the specific oxetane compound (A) is a fluorinated linear aliphatic liquid epoxy resin represented by the following general formula (2). The epoxy resin has a low viscosity, and by using this epoxy resin, it is possible to reduce the viscosity of the entire resin composition.

  The repeating number n in the above formula (2) is an integer of 2 to 10, preferably 4 to 10.

  Furthermore, in this invention, another epoxy resin can be used together with the said specific epoxy resin (B). Examples of the other epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, alicyclic epoxy resins, hydrogenated bisphenol A type epoxy resins, hydrogenated bisphenol F type epoxy resins, and the like. These may be used alone or in combination of two or more. Among these, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate represented by the following structural formula (3) is used in combination because it is transparent, has high heat resistance, and has good compatibility. It is preferable.

  When using these other epoxy resins in combination, the use ratio is preferably set to be 50% by weight or less of the total amount with the specific epoxy resin (B). That is, when it exceeds 50% by weight, the transparency tends to decrease or yellowing when left at high temperature tends to be severe.

The content ratio of the liquid epoxy resin (B) represented by the general formula (2) needs to be set to be in the range of 20 to 60% by weight of the total amount of (A) and (B). Particularly preferably, it is 30 to 50% by weight. At below 20% by weight, it is difficult to obtain the effect of improving sufficient solder heat resistance, when it exceeds 60 wt%, a compatible hard to a Luca et al and the specific oxetane compound (A).

  The photopolymerization initiator (C) used together with the specific oxetane compound (A) and the specific epoxy resin (B) is not particularly limited, and is an aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium salt. Aromatic sulfoxonium salts, metallocene compounds, iron arene compounds, and the like can be used. Among these, from the viewpoint of photocurability, aromatic sulfonium salts are preferable, and aromatic sulfonium / hexafluorophosphonium compounds, aromatic sulfonium / hexafluoroantimonate compounds, or a combination of both is preferable. From the viewpoint of Furthermore, a photosensitizer, an acid proliferation agent, etc. can be added as needed with the said photoinitiator (C).

  The content of the photopolymerization initiator (C) is 1 to 15 parts with respect to 100 parts by weight (hereinafter abbreviated as “part”) of the total amount of the specific oxetane compound (A) and the specific epoxy resin (B). It is preferable to set to 2 to 10 parts, particularly preferably 2 to 10 parts.

  In addition to the above (A) to (C), the ultraviolet curable resin composition of the present invention includes flexible materials such as silane-based or titanium-based coupling agents, synthetic rubbers, and silicone compounds in order to improve adhesiveness. A compound such as a property-imparting agent, and other additives such as an antioxidant and an antifoaming agent can be appropriately blended as necessary.

  The ultraviolet curable resin composition of the present invention can be obtained, for example, by blending at a predetermined ratio and melt-mixing using the above-mentioned (A) to (C) and further other additives as necessary.

  The ultraviolet curable resin composition thus obtained can be cured by, for example, irradiating ultraviolet rays with a UV lamp or the like and then performing post-curing at a predetermined temperature.

  Further, the light transmittance after curing of the ultraviolet curable resin composition of the present invention is usually 95% or more in a visible light region (wavelength 500 to 900 nm) and an infrared region in a 25 ° C. atmosphere when the thickness is 140 μm. Particularly preferably, it is 98% or more.

  Next, examples will be described together with comparative examples.

  First, each component shown below was prepared.

[Oxetane compound 1]
3-ethyl-3- (phenoxymethyl) oxetane represented by the structural formula (1) (OXT-211 manufactured by Toagosei Co., Ltd.)

[Oxetane compound 2]
Bifunctional oxetane compound represented by the following structural formula (4) (OXT-121, manufactured by Toagosei Co., Ltd.)

[Epoxy compound 1]
Fluorinated linear aliphatic epoxy resin represented by the general formula (2) (n = 4)

[Epoxy compound 2]
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate represented by the following formula (3) (manufactured by Daicel Chemical Industries, Celoxide 2021P)

[Epoxy compound 3]
Bisphenol F epoxy resin (Japan Epoxy Resin, YL-6753)

(Photopolymerization initiator)
Sulfonium hexafluoroantimony polymerization initiator (Asahi Denka Co., SP-170)

[Coupling agent]
γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone, KBM-403)

〔Antioxidant〕
HCA (manufactured by Sanko Chemical Co., Ltd.)

[Examples 1-7, Comparative Examples 1-6]
Each ultraviolet-ray curable resin composition was produced by mix | blending each compounding component shown in the following Table 1-Table 2 in the ratio shown to the same table, and melt-mixing (condition: 25 degreeC).

  Using the ultraviolet curable resin compositions of Examples and Comparative Examples thus obtained, the initial transmittance after curing, the transmittance at the solder temperature (260 ° C.), the transmittance decreasing rate, and The peeling observation after the pressure cooker test (PCT) was measured and evaluated according to the following methods. These results are shown in Tables 3 to 4 below.

[Each transmittance and transmittance reduction rate]
A sample for transmittance evaluation was produced as follows. That is, a gap of 140 μm was formed using a spacer between two Pyrex (registered trademark) glasses (size: 40 mm × 20 mm). Next, this gap was filled with an ultraviolet curable resin composition utilizing a capillary phenomenon, and then cured by irradiating with ultraviolet rays to prepare a transmittance evaluation sample. The curing by ultraviolet irradiation was performed by irradiating light at 9000 mJ / cm ² using a 500 W UV lamp (high pressure mercury lamp) and then performing post-curing at 100 ° C. for 1 hour. Next, the initial transmittance (25 ° C.) at a wavelength of 850 nm was measured using this sample, and then the transmittance at a wavelength of 850 nm was measured again for the sample after being placed in a dryer at 260 ° C. for 30 minutes. And the decreasing rate of the transmittance | permeability was computed from each value of the said initial transmittance and the transmittance | permeability in 260 degreeC. A spectrophotometer (UV-3101PC, manufactured by Shimadzu Corporation) was used for the measurement of transmittance.

[Peeling observation after PCT]
A sample similar to the sample used for the transmittance measurement was prepared, and a pressure cooker test was performed at 121 ° C. × 100% × 202.6 kPa for 24 hours. As a result, the presence or absence of peeling of the sample was visually observed.

  From the above results, the example product was high in both transmittances, and thus the transmittance reduction rate was very small. This shows that it is excellent in heat resistance. Further, in the peeling observation after PCT, it was completely adhered or only a slight peeling was confirmed at the corner portion. This shows that it is excellent also in moisture resistance.

  On the other hand, Comparative Examples 1 and 2 that do not use a specific oxetane compound and a specific epoxy compound, and Comparative Example 4 that uses an oxetane compound other than a specific oxetane compound and a specific epoxy compound, and a specific oxetane compound In addition, Comparative Example 6 using a combination of a normal epoxy compound and a specific epoxy compound alone, or Comparative Examples 3 and 5 using only a specific oxetane compound, both have a transmittance decrease rate in the example products. In comparison with the observation after the PCT, peeling was confirmed over the entire surface, but peeling was confirmed in the peripheral portion, and it is clear that both heat resistance and moisture resistance are inferior.

  The ultraviolet curable resin composition of the present invention is, for example, an optical component used in the field of optical communication and a transparent resin used for assembling optical components, in particular, fixing lenses, sealing optical device packages, and V-groove substrates. It is used for fixing optical fibers, molding materials such as optical waveguides (AWG) and lenses.

Claims (2)

An ultraviolet curable resin composition containing the following (A) to (C), wherein the content ratio of the following (A) is 40 to 80% by weight in the total amount of (A) and (B) The ultraviolet curable resin composition characterized by being set and the content rate of following (B) being set to 20 to 60 weight% in the total amount of (A) and (B) .
(A) 3-ethyl-3- (phenoxymethyl) oxetane represented by the following structural formula (1).

(B) Liquid epoxy resin represented by the following general formula (2).

(C) Photopolymerization initiator. In addition to the above (A) to (C), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate represented by the following structural formula (3) is added in a total amount with the above (B). The ultraviolet curable resin composition according to claim 1, which is contained so as to be 50% by weight or less .