JPH0980251A - Adhesive for fixing optical component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the adhesive having good workability and high reliability both of which can not be attained by any conventional metal joining method or with any conventional resinous adhesive. SOLUTION: This adhesive is obtained by blending 30% of alicyclic epoxy Celloxide 2021(R) (manufacturer: DAISERU KAGAKU KOGYO K. K.), 2% of 1,6-hexanediol, 1.5% of a photo-cationic curing catalyst SP-150(R) (manufacturer: ASAHI DENKA KOGYO K. K.), 56.5% of fused spherical silica (A) that has a 6μm average particle size and contains no coarse particle having a >=7μm particle size and 10% of fused fragmental silica (B) that has a 12μm average particle size and contains no coarse particle having a >=70μm particle size together and kneading the resulting blend with three rolls for 10min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component, and more particularly to an adhesive for fixing and fixing optical fibers.

[0002]

2. Description of the Related Art In recent years, with the rapid development of information society,
Demands for optical fibers and photoelectric conversion elements are also increasing in the fields of optical communication and home appliances. With regard to optical fibers, in particular, the waveguide and the optical fiber were conventionally joined by metal joining methods such as laser welding and solder joining, but there were problems such as poor fixing accuracy and inability to apply to parts that dislike high temperatures. . Recently, resin-based adhesives have also appeared, but generally, a large amount of inorganic filler is added to reduce curing shrinkage, and it is a hard and brittle material. There are problems such as peeling.

[0003]

The present invention has been made as a result of extensive studies in order to solve the above-mentioned conventional problems, and could not be achieved by the conventional metal bonding method or resin adhesive. The present invention relates to an adhesive for fixing optical components, which has good workability and high reliability.

[0004]

The present invention has a linear expansion coefficient (1 / ° C.) × Young's modulus (kgf / mm ² ) of 0.04 or less and a linear expansion coefficient of 3 × 10. ^-5 (1 / ° C)
It is an adhesive for fixing an optical component, characterized in that:

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Generally, when the stress applied to the interface between a resin and an insert (insert, for example, an optical fiber) is σ, when the linear expansion coefficient of the insert is sufficiently smaller than that of the resin, σ = ∫α * Edt (α : Linear expansion coefficient, E: Young's modulus,
t: temperature), and the linear expansion coefficient and Young's modulus are not uniquely determined independently, but are determined by the product of the linear expansion coefficient and Young's modulus. In the present invention, as a result of intensive investigations focusing on this fact, as a result, the product of the linear expansion coefficient (1 / ° C.) and the Young's modulus (kgf / mm ² ) of the cured product of the adhesive is 0.04 or less and the linear expansion is It was found that when the coefficient was 3 × 10 ⁻⁵ (1 / ° C.) or less, the stress was reduced, cracks and peeling did not occur in the temperature cycle test, and the adhesive strength after the temperature cycle test was extremely high.

When the coefficient of linear expansion exceeds 3 × 10 ^-5 (1 / ° C), even if the coefficient of linear expansion × Young's modulus is 0.04 or less, the resin or adhered to the resin under the thermal shock conditions such as temperature cycling. Residual strain gradually accumulates at the interface with the body, causing problems. Regarding the resin used, from the viewpoint of adhesiveness and ease of alignment, which is important in adhesion of optical components, epoxy resin that can be position-fixed in a short time alone or combined with thermosetting, and a cationic curing system can be used. preferable. Further, in the case of a cationic curing system, an alicyclic epoxy having a fast curing rate is 6% by weight of the epoxy resin.
The content of 0% or more is more preferable, and such an alicyclic epoxy resin is represented by 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate, and has a cycloalkene dicyclic ring. The thing which oxidizes a heavy bond with a peroxide and introduce | transduces an epoxide can be illustrated.

Further, this resin system contains a compound having two or more hydroxyl groups in one molecule, more preferably a polyhydric alcohol, from the viewpoint of imparting flexibility to the resin and accelerating the curing rate. preferable. Examples of the polyhydric alcohol include hexanediol, neopentyl glycol, trimethylolpropane, glycerin and the like. However, there is no particular problem even if it has a phenolic hydroxyl group such as a phenol resin other than alcohol. The ratio of the addition amount A of polyhydric alcohol to the addition amount B of epoxy resin is A: B =
It is preferably in the range of 5:95 to 50:50. When the polyhydric alcohol is too small, the cured product tends to be slightly brittle or the curing is delayed, and when it is too large, poor curing occurs.

Triarylsulfonium salts are widely used as photo-cationic curing catalysts as the curing catalysts used in the cationic curing system, but other curing catalysts based on iodonium salts and diazonium salts are known to those skilled in the art. It is a thing. Examples of the thermal cation curing catalyst include general protonic acids, Lewis acids, trialkyloxonium salts, carbonium salts, diazonium salts, alkylating agents, ammonium salts, sulfonium salts, phosphonium salts and the like. However, considering the ease of alignment of the optical parts, it is preferable to use the photocationic curing catalyst, but there is no problem even if the thermal cationic curing catalyst is used.

The filler used in the present adhesive is preferably an inorganic filler. Specifically, calcium carbonate, crystalline silica,
Fused silica, alumina, magnesia, clay, talc,
Although ceramic powder, glass fiber, etc. are exemplified, fused silica is preferable in consideration of the coefficient of linear expansion, and the addition amount thereof is 40% or more and 80% in the ratio of the total weight of the adhesive.
The following is preferred. If it is less than 40%, the coefficient of linear expansion becomes too large, and if it is more than 80%, the fluidity is remarkably reduced and the workability is deteriorated. 50% by weight in the total fused silica in order to develop better fluidity.
The above is more preferably spherical fused silica. Further, in the present invention, an elastomer, a defoaming agent, a coupling agent or the like for obtaining flexibility may be added if necessary.

When the adhesive for fixing optical parts in the present invention is used for fixing V-grooves of an optical fiber, for example, after alignment, the adhesive is applied with a dispenser or the like and ultraviolet light from a high pressure mercury lamp or a metal halide lamp is used. Then, cure and fix. In this case, it is advantageous to use the thermal cation curing together when there are shadows where light cannot pass or when the film thickness is large.

[0011]

【Example】

(Example 1) Alicyclic epoxy celoxide 2021 30%, 1,6-hexanediol 2% manufactured by Daicel Chemical Industries, Ltd. Photocationic curing catalyst SP150 manufactured by Asahi Denka Co., Ltd.
Fused spherical silica A with 1.5%, average particle size of 6 microns and coarse particles of 70 microns or more cut 56.5%, fused crushed silica B with average particle size of 12 microns and 70 coarse particles or more cut B 10 0.0% was blended and kneaded with a triple roll for 10 minutes to obtain an adhesive. The linear expansion coefficient of this cured product was measured at a temperature rising rate of 5 ° C./min with a thermomechanical analyzer, and the Young's modulus was measured at room temperature using Tensilon. The curing conditions are shown in Table 2. To measure the adhesive strength, a glass test piece as shown in FIG. 1 was prepared, and light was irradiated with a 5000 W high-pressure mercury lamp by the method as shown in FIG. 2 to bond the test piece, and then 5 mm / mi
Immediately after adhesion in the tensile mode with n and the lower limit of −40 ° C.,
The change in the adhesive strength after 500 cycles of the upper limit of 85 ° C. was observed. For further confirmation, quartz 125
A single mode optical fiber having a diameter of micron was fixed in a V groove, and a temperature cycle of 500 cycles under the same conditions as described above was performed to check for defects. The results are shown in Tables 1 and 2.

[0012]

[Table 1] * 1: Alicyclic epoxy resin manufactured by Daicel Chemical Industries * 2: Alicyclic epoxy resin manufactured by Asahi Denka Co., Ltd. * 3: Bisphenol A type epoxy resin with an epoxy equivalent of 185 * 4: Hydrogenated bisphenol A manufactured by Shin Nippon Rika * 5: Sumitomo Durez Phenol Novolak * 6: Asahi Denka Kogyo Photo Cationic Curing Catalyst * 7: Asahi Denka Kogyo Cationic Curing Catalyst

[0013]

[Table 2]

(Examples 2 to 4 and Comparative Examples 1 and 2) All formulations were carried out as shown in Table 1, and the evaluation method was carried out in the same manner as in Example 1. The results are summarized in Table 2. (Comparative Examples 3 and 4) Comparative Examples 3 and 4 were also made into materials according to the formulation of Table 1 and evaluated, but as shown in Table 2, the viscosity was too high or the curability was poor, and the evaluation was stopped.

[0015]

The adhesive for fixing optical parts of the present invention is an adhesive excellent in workability and high reliability, which is unprecedented, especially in temperature cycle property.

[Brief description of drawings]

FIG. 1 is a side view and a top view of a glass test piece.

FIG. 2 is a bonding method. The amount of ultraviolet light used after passing through the glass plate was measured to determine the curing conditions.

[Explanation of symbols]

 1 Test piece shown in FIG. 1 2 Adhesive 3 50 mm × 50 mm × 3 mm thick glass plate 4 UV irradiation direction 5 Adhesive force measurement direction 6 Tensilon chuck attachment part

Claims (5)

[Claims] 1. An adhesive for adhering and fixing optical components such as optical fibers, wherein the cured product of the adhesive has a coefficient of linear expansion (1 / ° C.) × Young's modulus (kgf / mm ² ) of 0.04 or less, and An adhesive for fixing optical components, which has a linear expansion coefficient of 3 × 10 ⁻⁵ (1 / ° C.) or less. 2. The adhesive is (a) an epoxy resin,
(B) a compound having two or more hydroxyl groups in one molecule, (c)
The adhesive for fixing an optical component according to claim 1, wherein a cation curing catalyst and (d) an inorganic filler are essential. 3. The inorganic filler of the adhesive component (d) is fused silica, the content of which is 40% by weight (hereinafter simply abbreviated as%) or more in a weight fraction of the adhesive, and 80.
The adhesive for fixing an optical component according to claim 1, which is not more than%. 4. The adhesive for fixing an optical component according to claim 1, wherein 50% by weight or more of the fused silica as the component (d) in claim 3 is spherical fused silica. 5. The alicyclic epoxy resin accounts for 60% by weight or more of the epoxy resin of component (a), and the compound having two or more hydroxyl groups in one molecule of component (b) is a polyhydric alcohol. And the addition weight of (b) is A and the addition weight of the epoxy resin is B, A: B = 5: 95
To 50:50, and the curing catalyst as the component (c) is a photocationic curing catalyst.