JPS6363503B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for coating optical glass fibers for light transmission. Optical glass fibers used for light transmission are brittle, easily damaged, and have poor flexibility, and are easily destroyed by even the slightest external force due to such scratches. Therefore, conventionally, optical glass fibers have been coated with a resin on their surfaces immediately after being manufactured from glass rods. Conventionally, epoxy resin, urethane resin, etc. have been used as such resin coating materials.
Since it takes a long time to cure, productivity is poor, and due to insufficient curing, adhesion to glass fibers is insufficient, making it unsatisfactory in terms of long-term reliability. Furthermore, since such a resin coating lacks flexibility, there is a drawback that the transmission characteristics are impaired by lateral pressure. This invention was made to solve the above problems, and in particular, it has a low viscosity, excellent adhesion to optical glass fibers, a high curing speed, and a flexible resin coating. It is an object of the present invention to provide certain optical glass fiber coating compositions. That is, the composition for coating optical glass fibers of the present invention contains an unsaturated polyester and a polyallylic ester, and the unsaturated polyester contains a long chain saturated aliphatic dibasic acid having 12 to 20 carbon atoms. Consists of an unsaturated polyester used as a component of the basic acid component, and the polyvalent allyl ester is selected from diallyl esters of aliphatic or aromatic dibasic acids and triallyl esters of cyanuric acid or isocyanuric acid. It is characterized by comprising at least one type of polyvalent allyl ester. In this way, in this invention, a specific polyvalent allyl ester is used as a crosslinking agent together with a specific unsaturated polyester, and in particular, the polybasic acid component in the unsaturated polyester is Since it is composed of a saturated polybasic acid with a very long chain length, very good results are achieved in flexibility after curing, and according to the composition composed of the above composition, optical glass fiber A low viscosity composition suitable for coating is obtained, and its curing speed is also increased. The unsaturated polyester used in this invention has a carbon number such as dodecanedicarboxylic acid.
A long-chain saturated aliphatic dibasic acid with 12 to 20 carbon atoms is used as a component of the polybasic acid component, but those with less than 12 carbon atoms do not have a sufficient flexibility improvement effect after curing. In addition, those with carbon numbers exceeding 20 are generally difficult to obtain. The above-mentioned long-chain saturated aliphatic dibasic acid accounts for 10 to 90 mol%, particularly preferably 30 to 80 mol%, of the polybasic acid component, that is, the total amount of unsaturated polybasic acid and saturated polybasic acid. It is better to occupy If this amount is too small, the cured film will lack flexibility, and if it is too large, the curing speed of the coating composition will be undesirably low. Saturated polybasic acids other than the long-chain saturated aliphatic dibasic acids mentioned above can also be used, but their proportions in the saturated polybasic acids are
The content is preferably 50 mol% or less. Examples of such saturated polybasic acids include aliphatic saturated dihydrochloric acid groups having 11 or less carbon atoms such as adipic acid, aromatic polybasic acids such as phthalic anhydride, terephthalic acid, trimellitic anhydride, and pyromellitic acid, and hexahydrochloric acid. Any alicyclic polybasic acid such as phthalic anhydride can be used. As the unsaturated polybasic acids used together with these saturated polybasic acids, unsaturated dibasic acids such as maleic anhydride, fumaric acid, itaconic acid, and citraconic acid are usually used. Further, the polyhydric alcohol component for obtaining the unsaturated polyester of the present invention is not particularly limited, and various polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin can be used arbitrarily. Particularly preferably average molecular weight
200-1000 polyethylene glycol, polypropylene glycol, 1,4-butanediol,
Long chain glycols such as 1,6-hexanediol, diethylene glycol and dipropylene glycol are preferably used. The above-mentioned unsaturated polyester of the present invention is produced by reacting the above-mentioned polyhydric alcohol component and polybasic acid component according to a conventional method, preferably in a ratio of equimolar or approximately equimolar hydroxyl groups and carboxyl groups. Just let it happen. The appropriate molecular weight of the unsaturated polyester is about 500 to 10,000. The coating composition of the present invention is made by blending such an unsaturated polyester with a polyvalent allyl ester as a crosslinking agent. Polyvalent allyl esters include diallyl esters of aliphatic or aromatic dibasic acids such as diallyl adipate, diallyl sebacate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diethylene glycol bis(allyl carbonate), and diallyl itaconate; There are triallyl esters of cyanuric acid or isocyanuric acid, that is, triallyl cyanurate or triallyl isocyanurate, and at least one of these polyvalent allyl esters is used. The blending ratio of this polyvalent allyl ester is selected to optimize the viscosity, curing speed, and flexibility of the cured film of the resulting coating composition, but it is usually a large amount relative to 30 to 90 parts by weight of the unsaturated polyester. The proportion of the polyvalent allyl ester is preferably 70 to 10 parts by weight, preferably 50 to 20 parts by weight of the polyvalent allyl ester to 50 to 80 parts by weight of the unsaturated polyester. In addition, in addition to the above polyvalent allyl ester, other crosslinking agents such as 2-ethylhexyl (meth)
Acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di( (meta) such as acrylate
There is no problem even if acrylic ester is used in combination. The coating composition of this invention is cured with a radical polymerization initiator or a photopolymerization initiator. For these, conventionally known initiators can be used as appropriate. Specific examples of radical polymerization initiators include benzoyl peroxide and t-butyl peroxybenzoate, and specific examples of photopolymerization initiators include acetophenone, benzoin isopropyl ether, and benzophenone. These initiators are usually used in an amount of 0.1 to 10% by weight of the coating composition. The optical glass fiber coating composition of the present invention may further contain a modifying resin and various additives as required, and may be diluted with a solvent for use if desired. The modifying resin is used in an amount equal to or less than the amount of the unsaturated polyester used, preferably 1/4 or less. Examples of the modifying resin include epoxy resin, polyamide, polyurethane, polyether, polyamideimide, silicone resin, and phenol resin. Examples of the additives include curing accelerators such as cobalt naphthenate, zinc naphthenate, and dimethylaniline, organosilicon compounds, and surfactants. As described above, the optical glass fiber coating composition of the present invention has carbon atoms as one component of the polybasic acid component.
A liquid composition containing an unsaturated polyester using a long chain saturated aliphatic dibasic acid of 12 to 20 and the specific polyvalent allyl ester, as shown in the examples below. It has a significantly lower viscosity than a coating composition made of epoxy resin, for example, and has a high curing speed, which not only improves the productivity of optical glass fibers but also forms a flexible coating and Increases the strength and reliability of glass fiber. The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, the following parts indicate parts by weight. Example 1 1 with stirrer, thermometer and reflux condenser
In a four-necked flask, add 29.4 g of maleic anhydride (0.3
mol), 239.4 g (0.7 mol) of long chain saturated aliphatic dibasic acid with 20 carbon atoms (SB-20 manufactured by Okamura Yusha Co., Ltd.) and 62 g (1.0 mol) of ethylene glycol, and
The reaction was carried out at 210°C for 5 hours to obtain an unsaturated polyester with an acid value of 25. A composition for coating optical glass fibers of the present invention was prepared by dissolving 30 parts of diallylitaconate in 70 parts of this unsaturated polyester and adding 5 parts of benzoin isopropyl ether as a photopolymerization initiator. Its properties are shown in Table 2. Example 2 In a flask similar to Example 1, maleic anhydride was added.
49g (0.5mol), dodecanedicarboxylic acid 115g
(0.5 mol) and 1,6-hexanediol 118
7 g (1.0 mol) at a temperature of 150 to 200℃.
After a period of reaction, an unsaturated polyester with an acid value of 18 was obtained. A composition for coating optical glass fibers of the present invention was prepared by dissolving 20 parts of triallyl isocyanurate and 1 part of t-butyl peroxybenzoate in 80 parts of this unsaturated polyester. Its properties are shown in Table 2. Examples 3 to 7 Example 5 of the present invention was prepared in the same manner as in Example 2, except that in place of 20 parts of triallylisocyanurate, the polyvalent allyl ester listed in the following Table 1 was used in the number shown in the same table. A seed optical glass fiber coating composition was prepared. These properties are shown in Table 2.

[Table] Comparative Example 1 Maleic anhydride was added to the same flask as in Example 1.
29.4g (0.3mol), sebacic acid 141.4g (0.7mol)
and 62 g (1.0 mol) of ethylene glycol were charged and reacted at 180 to 200°C for 17 hours to obtain an unsaturated polyester with an acid value of 30. A comparative optical glass fiber coating composition different from this invention was prepared by dissolving 30 parts of diallylitaconate in 70 parts of this unsaturated polyester and adding 5 parts of benzoin isopropyl ether as a photopolymerization initiator. Its properties are shown in Table 2. Comparative example 2 Epoxy resin Epon-828 (manufactured by Shell Oil Co., Ltd.) 100
A composition for coating optical glass fibers different from this invention was prepared by dissolving 5 parts of 2-ethyl-4-methylimidazole in 5 parts of 2-ethyl-4-methylimidazole. Its properties are shown in Table 2.

[Table] In Table 2 above, Shore hardness A was measured as follows. Examples 2 to 7 and comparative example 2
Regarding the compositions, each composition was heated and cured at 150° C. for 15 minutes to prepare a plate with a thickness of 2 mm, and this was used for measurement. For Example 1 and Comparative Example 1, two high-pressure mercury lamps (input
120W/cm, lamp output 5KW) at a position 15cm below the parallel light source (conveyor speed
50 m/min) and a thickness of 100 μm, and this was used for measurement. Next, the above Examples 1 to 7 and Comparative Examples 1 and 2
Optical glass fibers were actually coated using the composition for coating optical glass fibers as shown in Test Examples 1 to 9 below, and the performance thereof was tested. Test Example 1 In a process subsequent to the spinning process, the coating composition shown in Example 1 was applied to the surface of an optical glass fiber with a diameter of 125 μm spun at a speed of 30 m/min, and then exposed to ultraviolet light (2 lamp outputs of 2 KW). was irradiated and cured. The optical glass fiber outer diameter after coating is approx.
The diameter was 250 μm, and the surface was uniform. Moreover, the breaking strength was 5.7 kg (sample length 10 m, average value of 20 samples), and no increase in transmission loss was observed up to -40°C. Test Example 2 In Test Example 1, the coating composition shown in Comparative Example 1 was used instead of the coating composition of Example 1,
The optical glass fibers were otherwise coated in the same manner as in Test Example 1. Optical glass fiber outer diameter after coating is approximately 250μm
However, the breaking strength was 5 kg, which was lower than that of Test Example 1, and furthermore, a significant increase in transmission loss was observed at -40°C. Test Example 3 In a step subsequent to the spinning process, the coating composition shown in Example 2 was applied to the surface of an optical glass fiber with a diameter of 125 μm spun at a speed of 20 m/min, and then heated in an electric furnace (long-length) at 450°C. 1 m). The outer diameter of the optical glass fiber after coating is approx.
The diameter was 230 μm, and the surface was uniform. In addition, the breaking strength of the obtained optical glass fiber (sample length 10
m, average value of 20 samples) is 5 kg, -40℃
No increase in transmission loss was observed up to this point. Test Examples 4-8 Instead of the coating composition of Example 2, Examples 3-
Except that each coating composition of No. 7 was used.
A coating test similar to Test Example 3 was conducted. In any case, the outer diameter of the optical glass fiber after coating is approximately 225 ~
It was in the range of 235 μm and had a uniform surface.
Moreover, the breaking strength was in the range of 5 to 6 kg in all cases, and no increase in transmission loss was observed up to -40°C. Test Example 9 In Test Example 3, the coating composition shown in Comparative Example 2 was used instead of the coating composition of Example 2,
Optical glass fibers were obtained by curing in an electric furnace heated to 650°C. The outer diameter of this fiber is 150~310μ
It varied within a range of m. Furthermore, a rapid increase in transmission loss was observed in the obtained optical glass fiber at temperatures below -20°C. As mentioned above, the composition for coating optical glass fibers of the present invention has a fast curing speed, so it can be coated quickly and with good adhesion during the spinning process of optical glass fibers, and it is highly flexible after curing, so it can be used for transmission. There is an advantage that an optical glass fiber coating with excellent properties can be obtained.

Claims (1)

[Claims] 1. An unsaturated polyester using a long-chain saturated aliphatic dibasic acid having 12 to 20 carbon atoms as a polybasic acid component, a diallyl ester of an aliphatic or aromatic dibasic acid, and cyanuric acid. 1. A composition for coating optical glass fibers, comprising at least one polyvalent allyl ester selected from triallyl esters of acids or isocyanuric acid. 2 Long chain saturated aliphatic dibasic acid with 12 to 20 carbon atoms in unsaturated polyester is 10 to 90 of the polybasic acid component
The optical glass fiber coating composition according to claim 1, which accounts for mol %. 3. The composition for coating optical glass fibers according to claim 1 or 2, which contains 30 to 90 parts by weight of unsaturated polyester and 70 to 10 parts by weight of polyvalent allyl ester.