JP5116730B2 - UV curable epoxy 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, which has transparency and excellent adhesive strength to pass optical signals with low loss, and contaminates other components. The present invention relates to a UV-curable transparent epoxy resin composition that generates low outgas (gas that volatilizes under high temperature conditions), and in particular, fixing lenses, sealing optical device packages, fixing optical fibers to V-groove substrates, and light The present invention relates to an ultraviolet curable epoxy resin composition suitable as an optical component material such as a waveguide (AWG) and a lens.

  In recent years, a method using an adhesive has been used in the assembly of precision optical fiber connector parts. At the time of this assembly, the adhesive retains excellent adhesion to quartz glass and optical fiber as well as high-temperature and high-humidity environment from the viewpoint of long-term reliability, as well as short-time curing. It was requested. Moreover, since the alignment mark for positioning and the visibility of the fiber are used, and optical components are disliked by thermal stress, photo-curing adhesives such as ultraviolet curing are often used. Conventionally, glass such as quartz has been mainly used for optical waveguides. However, in recent years, development of polymer waveguides has been progressing, and for example, various materials such as acrylate, epoxy resin, polyimide and polysilane are used. Research is ongoing.

  When an organic material is used for such an application, there is a problem of outgas that volatilizes from the resin component. For example, the above epoxy resins and acrylates generally have a problem that when exposed to high temperatures, low molecular weight components volatilize or decompose, resulting in outgassing. When these volatile components adhere to the surface of an optical component such as a lens, a photodiode, or a laser diode, or an optical device disposed in a portion through which an optical signal passes, it is a problem that causes the signal to decrease.

  On the other hand, the polyimide, polysilane and the like are not practical because they generate less outgas but have a high curing temperature of 300 ° C. or higher, which damages optical devices and optical components themselves.

  By the way, although microlenses are widely used for optical applications, examples of producing microlenses with resin are increasing from the viewpoint of cost and mass productivity. Such a resin microlens has been produced by a conventionally known molding method, but in recent years, a molding method by an inkjet method has been proposed (see Patent Document 1 and Patent Document 2).

JP 2000-180605 A JP 2002-331532 A

  In order to eject a small amount of droplets of picoliter level by such an ink jet method, it is required to have a very low viscosity, but in order to achieve a low viscosity, the viscosity is increased by adding a diluent or the like. When the value is lowered, there is a problem that a large amount of outgas is easily generated.

  The present invention has been made in view of such circumstances, and is useful as an optical component that generates very little outgas. Further, it is useful as an optical component material such as an optical waveguide and a lens, and an ultraviolet curable adhesive for fixing an optical component. It is an object of the present invention to provide an ultraviolet curable epoxy resin composition that is an ultraviolet curable type that does not require high-temperature treatment and that is transparent to optical signals.

（ａ）３，４−エポキシシクロヘキシルメチル−３，４−エポキシシクロヘキサンカルボキシレートおよび３，４−エポキシシクロヘキシルエチル−３，４−エポキシシクロヘキサンカルボキシレートの少なくとも一方。

（Ｂ）芳香族スルホニウム塩。 In order to achieve the above-mentioned object, the ultraviolet curable epoxy resin composition of the present invention has a configuration containing the following (A) and (B).
(A) At least one of a linear aliphatic epoxy resin represented by the following general formula (1) and a linear fluorinated epoxy resin represented by the following general formula (2), and the following alicyclic ring And a linear aliphatic epoxy resin represented by the following general formula (1) and a linear fluorinated epoxy resin represented by the following general formula (2): One content is an epoxy resin set in the range of 40 to 90% by weight in the entire epoxy resin component ( however, in the allyl epoxy resin represented by the following formula (3) and the following formula (4) Except for the naphthalene epoxy resins represented) .

(A) At least one of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 3,4-epoxycyclohexylethyl-3,4-epoxycyclohexanecarboxylate.

(B) Aromatic sulfonium salt.

  That is, the present inventors have made extensive studies in order to obtain an ultraviolet curable epoxy resin composition having reduced outgas generation and having high transparency after curing. In the process, in the case of cationic photopolymerization, it was found that the diglycidyl ether type epoxy resin generates a large amount of outgas in a high temperature atmosphere. As a result of further research based on this knowledge, it was found that generation of outgas is greatly reduced when an epoxy resin having no ether bond is used, and the linear aliphatic epoxy represented by the above general formula (1) The resin and at least one of the linear fluorinated epoxy resins represented by the general formula (2) are used, and the content is set in the range of 40 to 90% by weight in the entire epoxy resin component and the specific When the alicyclic epoxy resin (a) was used, the intended purpose was achieved and the present invention was reached.

  Thus, the present invention provides at least one of a linear aliphatic epoxy resin represented by the general formula (1) and a linear fluorinated epoxy resin represented by the general formula (2), and Containing a specific alicyclic epoxy resin and containing at least one of a linear aliphatic epoxy resin represented by the general formula (1) and a linear fluorinated epoxy resin represented by the general formula (2) It is an ultraviolet curable epoxy resin composition using an epoxy resin (A) and an aromatic sulfonium salt (B) whose amount is set in the range of 40 to 90% by weight in the whole epoxy resin component. For this reason, it has moderate transparency and high practicality with high moisture-resistant adhesive strength after initial and after moisture absorption. And the generation | occurrence | production amount of the outgas under high temperature conditions will be suppressed in the hardened | cured material. Therefore, when used for bonding optical fibers and optical grooves such as optical waveguides and V-grooves in optical communication systems, and for optical component materials such as optical waveguides and microlenses, other optical elements and electronic devices, A good optical system can be obtained without contaminating optical components and the like.

Next, embodiments of the present invention will be described in detail.
The ultraviolet curable epoxy resin composition of the present invention comprises at least one of a special linear aliphatic epoxy resin and a special linear fluorinated epoxy resin, and an epoxy resin containing a specific alicyclic epoxy resin ( It can be obtained by using A) and a specific photopolymerization initiator (B).

  The special linear aliphatic epoxy resin is represented by the following general formula (1). The special linear aliphatic epoxy resin represented by the formula (1) is produced, for example, as follows. That is, it can be obtained by oxidizing a desired compound having vinyl groups at both ends. The oxidation reaction can also be performed by direct oxidation with an organic peroxide such as perbenzoic acid, or by oxidation with hydrogen peroxide or gaseous oxygen using a heteropolyacid as a catalyst.

  The special linear fluorinated epoxy resin is represented by the following general formula (2). The special linear fluorinated epoxy resin represented by the formula (2) can be obtained, for example, by oxidizing a desired compound having vinyl groups at both ends, as described above. The oxidation reaction can also be performed by direct oxidation with an organic peroxide such as perbenzoic acid, or by oxidation with hydrogen peroxide or gaseous oxygen using a heteropolyacid as a catalyst.

  The content of at least one of the linear aliphatic epoxy resin represented by the formula (1) and the linear fluorinated epoxy resin represented by the formula (2) is 40 to 90 in the entire epoxy resin (A). It is necessary to set so as to occupy% by weight. More preferably, it is 50 to 70% by weight. That is, when the amount is less than 40% by weight, the amount of outgas generated increases. Conversely, when the amount exceeds 90% by weight, the curability deteriorates and the workability deteriorates.

  When the linear aliphatic epoxy resin represented by the formula (1) and the linear fluorinated epoxy resin represented by the formula (2) are used, the linear type represented by the formula (1) is used. Even if only the aliphatic epoxy resin is used, or only the linear fluorinated epoxy resin represented by the formula (2) is used, even if both are used in combination, Regardless of the reduction in outgas generation.

  Furthermore, a specific alicyclic epoxy resin is used together with the epoxy resin in the epoxy resin (A). By using the specific alicyclic epoxy resin in combination, the curability can be improved. As the specific alicyclic epoxy resin, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 3,4-epoxycyclohexylethyl-3,4-epoxycyclohexanecarboxylate are transparent. , Used from the viewpoint of high viscosity and reactivity. These may be used alone or in combination of two or more. And it is preferable to set the usage-amount of the said specific alicyclic epoxy resin to 60 weight% or less of the whole epoxy resin (A). More preferably, it is 40% by weight or less.

In the present invention, as the epoxy resin (A), at least one of a linear aliphatic epoxy resin represented by the above formula (1) and a linear fluorinated epoxy resin represented by the formula (2), and Although it may be composed of an epoxy resin system containing the specific alicyclic epoxy resin as an essential component, a conventionally known epoxy resin may be used. Specifically, general-purpose bisphenol type epoxy resins, hydrogenated bisphenol type epoxy resins, novolac type epoxy resins, glycidyl ether type epoxy resins, glycidyl ester type epoxy resins and the like can be used.

  As the specific photopolymerization initiator (B) used together with the epoxy resin (A), an aromatic sulfonium salt is used from the viewpoint of photocurability, and in particular, an aromatic sulfonium / hexafluorophosphonium compound, an aromatic sulfonium / A hexafluoroantimonate compound or a combination of both is preferred from the viewpoints of curability, adhesiveness, and outgas.

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

  In addition to the above components, the ultraviolet curable epoxy resin composition of the present invention includes a silane-based or titanium-based coupling agent, a flexibility imparting agent such as a synthetic rubber or a silicone compound, etc., in order to enhance adhesion. In addition, other additives such as an antioxidant and an antifoaming agent can be appropriately blended as necessary.

  The ultraviolet curable epoxy resin composition of the present invention includes, for example, a special linear aliphatic epoxy resin represented by the general formula (1) and a special linear fluorination represented by the general formula (2). At least one of the epoxy resins and an epoxy resin (A) containing a specific alicyclic epoxy resin, a specific photopolymerization initiator (B), and other additives as required are blended in a predetermined ratio. And then mixed.

  The ultraviolet curable epoxy 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.

  Next, examples will be described together with comparative examples.

  First, each component shown below was prepared.

[Epoxy resin 1]
Linear aliphatic epoxy resin represented by the general formula (1) [in formula (1), n = 4]

[Epoxy resin 2]
Linear aliphatic epoxy resin represented by the general formula (1) [in formula (1), n = 10]

[Epoxy resin 3]
Linear fluorinated epoxy resin represented by the general formula (2) [n = 4 in the formula (2)]

[Epoxy resin 6]
Diglycidyl ether type linear epoxy resin represented by the following formula (a) (manufactured by JER, YED-216D)

[Epoxy resin 7]
Bisphenol A type epoxy resin represented by the following formula (b) (JERO Co., Epicoat 825)

[Alicyclic epoxy resin]
Alicyclic epoxy resin represented by the following formula (c) (Dacel Chemical Co., Celoxide 2021P)

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

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

[Defoamer]
KS-68 (manufactured by Shin-Etsu Silicone)

[Coupling agent]
γ-glycidoxypropyltrimethoxysilane

[Examples 1 to 13 and Comparative Examples 1 to 6]
Each component shown in the following Tables 1 to 4 was blended and mixed in the proportions shown in the same table to prepare an ultraviolet curable epoxy resin composition.

Using the ultraviolet curable epoxy resin compositions of Examples and Comparative Examples thus obtained, the viscosity, outgas amount, light transmittance, and initial adhesive strength after curing at 25 ° C. The moisture resistance adhesive strength was measured and evaluated according to the following method. These results are also shown in Tables 5 to 8 below.

[Viscosity of epoxy resin composition]
The viscosity at 25 ° C. was measured using an E-type viscometer.

[Outgas amount]
The film was irradiated with light for 60 seconds using a 500 W UV lamp (high pressure mercury lamp) and then post-cured at 100 ° C. for 1 hour to produce a film having a thickness of 100 μm. And after measuring the initial weight of this film, it put into 125 degreeC dryer, left for 24 hours, took out, and measured the weight. From these weight changes (weight reduction rate), the outgas amount at 125 ° C. was calculated.

(Light transmittance)
A film having a thickness of 100 μm was prepared (the curing conditions were the same as above), and the light transmittance at a wavelength of 1300 nm was measured at 25 ° C. using a spectrophotometer (UV-3101PC, manufactured by Shimadzu Corporation).

[Initial adhesive strength / moisture resistant adhesive strength]
First, an ultraviolet curable epoxy resin composition was applied as an adhesive to a columnar quartz glass plate (length 3.3 mm × width 3.3 mm × thickness 5 mm), and then a quartz glass plate (length 20 mm × width 35 mm × thickness 2 mm). ) And bonded together, and the adhesive was cured under the following curing conditions to produce an adhesive piece. That is, the curing was performed by irradiating light for 60 seconds using a 500 W UV lamp (high pressure mercury lamp) and then performing a post cure at 100 ° C. for 1 hour.

  And the initial adhesive strength measured the adhesive strength of shear using the said adhesive piece and using the push pull gauge at 25 degreeC.

  Further, the moisture-resistant adhesive strength is determined by allowing the above-mentioned adhesive piece to stand for 24 hours under PCT conditions (121 ° C. × 202.6 kPa) to absorb moisture and then using a push-pull gauge at 25 ° C. It was measured.

  From the above results, it can be seen that the example products have a high light transmittance of 90% or more at 1300 nm in the visible light region and are excellent in transparency. Moreover, high numerical values were obtained for both the initial adhesive strength and the moisture-resistant adhesive strength. Moreover, the amount of outgas was also low, less than 0.5% by weight.

  On the other hand, in Comparative Examples 1 and 3 in which the content of each epoxy resin represented by the general formula (1) and the general formula (2) exceeds 90% by weight of the entire epoxy resin component, it is in an uncured state and measured. It was impossible. Moreover, in the comparative example 2 goods whose content of each epoxy resin represented by General formula (1) and General formula (2) is less than 40 weight% of the whole epoxy resin component, there is more outgas amount than an Example goods, In addition, the light transmittance decreased and the viscosity increased. And the comparative examples 4-6 products using the diglycidyl ether type linear epoxy resin and the bisphenol A type epoxy resin were inferior in transparency, and had a high outgas amount and low moisture-resistant adhesive strength. .

Claims (2)

An ultraviolet curable epoxy resin composition comprising the following (A) and (B):
(A) At least one of a linear aliphatic epoxy resin represented by the following general formula (1) and a linear fluorinated epoxy resin represented by the following general formula (2), and the following alicyclic ring And a linear aliphatic epoxy resin represented by the following general formula (1) and a linear fluorinated epoxy resin represented by the following general formula (2): One content is an epoxy resin set in the range of 40 to 90% by weight in the entire epoxy resin component (however, in the allyl epoxy resin represented by the following formula (3) and the following formula (4) Except for the naphthalene epoxy resins represented) .

(A) At least one of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 3,4-epoxycyclohexylethyl-3,4-epoxycyclohexanecarboxylate.

(B) Aromatic sulfonium salt. The content of at least one of the linear aliphatic epoxy resin represented by the general formula (1) and the linear fluorinated epoxy resin represented by the general formula (2) is 50% in the entire epoxy resin component. 70 wt% claim is set in a range of 1 Symbol placement ultraviolet-curable epoxy resin composition.