JPH0751454B2 - UV curable coating material for optical fiber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultraviolet curable coating material used for coating an optical fiber, and particularly to an ultraviolet curable coating for an optical fiber which is suitable for a primary coating of the optical fiber. It is about materials.

(Prior Art) Since an optical glass fiber used for optical transmission is fragile and easily damaged when left bare, it is generally broken by a slight force, so that a protective layer is formed by coating a resin after drawing the glass fiber. Conventionally, a thermosetting silicone resin is most often used as the protective layer. However, the silicone resin has a limited curing speed and is expensive, and since this is a method in which the curing proceeds while extracting hydrogen, there is a risk that the transmission characteristics may deteriorate due to the generation of hydrogen in the long term. . Therefore, a coating material that can be cured by irradiation with ultraviolet rays has been proposed.

On the other hand, in a generally used glass fiber for optical transmission, it is customary to secondly coat a resin material having high hardness on this coating. Therefore, the material that is primarily coated must have the function of relaxing the strain stress applied to the glass fiber due to the contraction and expansion of the highly hard secondary coating material in addition to the initial reinforcement after drawing the glass fiber. I have to. Therefore, the properties required for the primary coating are that it has appropriate flexibility as a cushioning material, such flexibility is maintained even at a low temperature of -40 ℃, and this flexibility is maintained for a long period of time. It is to have heat resistance and water resistance.

The present inventors have previously proposed an ultraviolet curable resin having excellent heat resistance and water resistance, which is used for coating a glass fiber. This resin is composed of a low molecular weight olefin polyol, but has a low glass transition temperature of -20 ° C to -30 ° C.
At this low temperature, the flexibility was poorly maintained and the curing rate was low. On the other hand, as another UV-curable resin, there is polyether polyol-based urethane acrylate, which has excellent flexibility retention and curing speed at low temperatures, but has a drawback of poor heat resistance and water resistance. .

(Object of the Invention) The object of the present invention is to maintain flexibility in a low temperature range, curing rate,
An object of the present invention is to provide an ultraviolet-curable coating material for optical fibers which is excellent in both heat resistance and water resistance.

(Structure of the Invention) The ultraviolet curable coating material for optical fibers according to the present invention comprises a compound of 100 parts of a low molecular weight polyolefin polyol having a hydroxyl group at the molecular end and 50 to 300 parts of a polyether polyol via a urethane group ( It is characterized in that it is mainly composed of a compound formed by adding a (meth) acrylic group.

By doing so, it is possible to obtain a material excellent in retention of flexibility at low temperature, curing rate, heat resistance and water resistance by compensating for the drawbacks of polyolefin and polyether polyol. In this case, the urethane group has a function of enhancing the compatibility with the low-molecular-weight polyolefin polyol and the polyether polyol, which are immediately separated even if they are mixed at the stage of the polyether and the compatibility between the two is poor because they are unsaturated compounds.

(Example) The Example of this invention is described in detail below. The UV-curable coating material of the present invention comprises a mixture of 100 parts of a low molecular weight polyolefin polyol having a hydroxyl group at the molecular end and 50 to 300 parts of a polyether polyol, to which a (meth) acrylic group is added via a urethane group. The main component is a compound, and a suitable reactive diluent, a photoreaction initiator, a thermal polymerization inhibitor, and the like are mixed therein. In the present invention, the low molecular weight polyolefin polyol is, for example, a telechelic polymer having a saturated hydrocarbon skeleton commercially available from Mitsubishi Kasei Co., Ltd., and has a molecular weight of 1,000 to 3,000 and is liquid at room temperature. Polyether polyol is polyethylene glycol, polypropylene glycol, polytetramethylene glycol or a copolymer of these and has a molecular weight of 800 to 3000. In this way, when the coating material is composed of a mixture of low molecular weight polyolefin and polyether polyol, the excellent heat resistance and water resistance of the low molecular weight polyolefin polyol and the flexibility of the polyether polyol in the low temperature range are excellent. It has both holding and curing rates. In this formulation, the low molecular weight polyolefin polyol and the polyether polyol were set to 100 parts and 50 to 300 parts, respectively, because the effects of obtaining the advantages of both are lost when the content exceeds these ranges.

As already mentioned, the urethane group immediately separates even when the low molecular weight polyolefin polyol and the polyether polyol are mixed at the polyol stage, and the compatibility of the two is poor, so that they act as unsaturated compounds to enhance the compatibility. Have.

Next, a method for producing the coating material of the present invention will be described. First, 50 to 300 parts of a polyether polyol is mixed with 100 parts of a low molecular weight polyolefin polyol to obtain a blend of both. The polyol compound was reacted with a diisocyanate compound and an unsaturated compound having a hydroxyl group in the presence of a catalyst such as tin octylate or butyltin dilaurate to obtain a ureta (meth) acrylate compound. Here, diisocyanate means tolylene diisocyanate, diphenylmethane diisocyanate, P-phenylene diisocyanate, hexamethylenediisocyanate,
Isophorone diisocyanate and the like. The unsaturated compound having a hydroxyl group includes 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and the like. In this urethane (meth) acrylate synthesis reaction, the order of addition of each component is not limited,
It is preferable to first add an isocyanate compound to the above-mentioned polyol formulation and allow it to sufficiently react, and then to react it with an unsaturated compound containing a hydroxyl group, because the stability of the resin composition is high.

The urethane compound containing an unsaturated group thus obtained is mixed with a suitable reactive diluent for decreasing the viscosity. The amount of the diluent added is usually 20 to 150 parts per 100 parts of the urethane compound. Examples of these reactive diluents include tetrahydrofurfuryl acrylate, 2
-Hydroxy-3-phenyloxypropyl acrylate, butoxyethyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, benzyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol diacrylate , 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropanate acrylate, pentaerythritol triacrylate or trade name Aronix M-11
There are phenoacrylate type such as 3 (Toagosei Co., Ltd.).

A photoreaction initiator and a thermal polymerization inhibitor can be further added to the coating material thus obtained. The photoinitiator consists of the above-mentioned urethane compound and reactive diluent in total of 10
0.1 to 10 parts, preferably 1 to 5 parts is added to 0 part. Examples of the photoreaction initiator include benzoin, benzoin methyl ether, benzoin butyl ether, benzophenone, Michler's ketone, benzyl, benzyl dimethyl ketal, anthraquinone, diacetyl, acetophenone, and thioxaton. Incidentally, a peroxide or the like may be added instead of the photoreaction initiator and heat-cured.

Further, in addition to the above additives, various antiaging agents may be added to improve the heat deterioration characteristics, and various surfactants may be added to adjust the adhesion to the surface of the glass fiber. Good.

Specific examples of the present invention will be given below together with comparative examples. still,
The characteristics of each Example and Comparative Example are summarized in the table.

Example 1 150 g of a low molecular weight polyolefin polyolefin resin (hydroxyl value 53, molecular weight about 2000) manufactured by Mitsubishi Kasei Co., Ltd. in a 1000 cc capacity flask equipped with a thermometer, a stirrer and a gas inlet tube.
And polytetramethylene glycol (hydroxyl value 55, molecular weight about 2000) 200g were weighed and dehydrated in a reduced pressure atmosphere at 100 ° C, then tin octylate 0.4g was added as a catalyst and kept at a temperature of 80 ° C. While adding 67 g of isophorone diisocyanate, the reaction was carried out for 2 hours while introducing nitrogen gas. Next, 38 g of 2-hydroxyethyl acrylate and 0.4 g of hydroquinone monomethyl acrylate were added and reacted at 80 ° C. for 3 hours. Resin product 70 thus obtained
Acronix M-113 (Toagosei Co., Ltd.)
20 parts, TC-110S (manufactured by Nippon Kayaku Co., Ltd.), and 5 parts Irgacure 651 (manufactured by Ciba-Gay-Key) were added to prepare a coating material. The viscosity of this material is 8,200 centipoise (3
Was 0 ° C). There was no liquid separation even if this material was left at 60 ° C. for 1 week.

Example 2 In a flask having a capacity of 1000 cc equipped with a thermometer, a stirrer and a gas inlet tube, 100 g of low molecular weight polyolefin resin (hydroxyl value 53, molecular weight about 2000) and polytetramethylene glycol (hydroxyl value 55, low molecular weight about 2000) were used. ) 200 g was weighed and dried under a reduced pressure atmosphere of 100 ° C., then 0.4 g of tin octylate was added as a catalyst, 55 g of hexamethylene diisocyanate was added while keeping the temperature at 80 ° C., and nitrogen gas was introduced. While reacting for 2 hours. Next, 38 g of 2-hydroxyethyl acrylate and 0.4 g of hydroquinone monomethyl acrylate were added and reacted at 80 ° C. for 3 hours. A coating material was prepared by adding 20 parts of Acronix M-113, 10 parts of TC-110S and 5 parts of Irgacure 651 to 70 parts of the resin product thus obtained. The viscosity of this material was 5,400 centipoise (30 ° C). There was no liquid separation even if this material was left at 60 ° C. for 1 week.

Comparative Example 1 A flask having a thermometer, a stirrer, and a gas inlet tube and having a capacity of 500 cc was charged with polytetramethylene glycol (hydroxyl value
55, molecular weight about 2000) 200 g was weighed and dehydrated in a reduced pressure atmosphere at 100 ° C., and then tin octylate 0.2 g was added as a catalyst,
43 g of isophorone diisocyanate while maintaining a temperature of 0 ° C
Was added and reacted for 2 hours while flowing in nitrogen gas.
After that, 23 g of 2-hydroxyethyl acrylate and 0.3 g of hydroquinone monomethyl ether were added, and the mixture was reacted at 80 ° C. for 3 hours. To 100 parts of this reaction product, 20 parts of Acronix M-113, 10 parts of TC-110S, Irgacure
5 parts of 651 were added to obtain a composition having a viscosity of 3,100 centipoise (30 ° C.).

Comparative Example 2 A composition was obtained under exactly the same conditions as in Comparative Example 1 except that 195 g of low molecular weight polyolefin polyol was used instead of polytetramethylene glycol in Comparative Example 1. The viscosity of this composition was 9,200 centipoise (30 ° C.).

The coating material obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was applied on a glass plate, and a sheet having a thickness of about 200 μm was irradiated with a high pressure mercury lamp of 80 W / cm and 2 KW at an irradiation dose of 400 mJ / cm. It was cured so that The characteristics of the sheet-like sample thus obtained are
Shown in the table. The values of 120 ° C, 30-day heating and 80 ° C, 30-day inundation indicate the residual rate (%) of the original product.

As can be seen from Table 1 above, the coating material of the present invention has excellent heat resistance, water resistance, and retention of mechanical properties at low temperatures. In addition, the coating material of each of Examples 1 and 2 was spun at a speed of 80 m / min to a diameter of 125 μ, and an outer diameter of 3 was applied to the surface of the optical fiber.
It was coated so as to have a thickness of 00 μ, and this was cured using an ultraviolet irradiator (D bulb) manufactured by Fusion. Desolite 950Y-101 resin manufactured by Desott Co.
An optical fiber core wire was obtained by coating and hardening to 00 μm. The optical fiber core wire thus obtained is -40 ° C.
No increase in transmission loss was observed under low temperature, and increase in transmission loss was rare even after heating at 80 ℃ for 30 days.

(Effects of the Invention) According to the present invention, as described above, it is possible to obtain an ultraviolet curable coating for optical fibers which is excellent in all of the flexibility retention in the low temperature range, the curing rate, the heat resistance and the water resistance. There is a real benefit.

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Claims (1)

[Claims] 1. A low molecular weight polyolefin polyolefin having a hydroxyl group at its molecular end and 100 parts of a polyether polyol.
A UV-curable coating material for optical fibers, which is mainly composed of a compound obtained by adding a (meth) acrylic group via a urethane group to a mixture with 300 parts.