JPS60118654A - Coating composition for optical fiber - Google Patents

Abstract

PURPOSE:The titled composition, obtained by incorporating a monofunctional acrylate of specific structure with a rubber component a polyurethane compound and a polymerization initiator in a specific proportion, and having improved flexibility and curability imparted thereto. CONSTITUTION:A coating composition for optical fibers consisting of 100pts.wt. liquid monofunctional (meth)acrylate expressed by the general formula (R is H or methyl group; R1 is monofunctional group having 6-18C chain or branched alkyl group), 2-100pts.wt. rubber component, 2-50pts.wt. polyurethane compound having urethane bonds as the main skeleton, 500-20,000 molecular weight and two or more (meth)acryloyl groups in one morecule and 0.05-30pts.wt. polymerization initiator. The resultant composition is inexpensive and has characteristics of being capable of curing easily by light, heat, etc. and dissolving optionally the rubber components.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an optical fiber coating composition useful as a protective coating for optical glass fibers.

Fiber optic cable has wide bandwidth and low loss.

It has excellent features such as non-induction, small diameter, and light weight, and is expected to become widely used.

This optical glass fiber is coated with a protective coating as soon as the fiber is spun from the molten state to avoid loss of fiber strength due to the formation of submicron cracks. This protective coating must be made of a flexible material that does not cause microbending, which causes transmission loss, and conventionally, thermosetting silicone resin has been mainly used. however,
From the viewpoint of general use, since the silicone resin itself is expensive in this conventional method, it is desirable to find a material that can be replaced with a cheaper material.

In view of the above circumstances, the inventor conducted extensive research to develop a flexible material useful as a protective coating material for optical glass fibers, and as a result, discovered that (meth)acrylates, which are commonly used as so-called reactive diluents, Among them, liquid monofunctional (
The meth)acrylate dissolves the rubber component to a high degree, and by adjusting the amount of this rubber component, it is possible to easily obtain the desired viscosity during coating of optical fibers. A curable resin composition for optical fibers is prepared by blending a polymerization initiator into a liquid resin composition prepared by adding a polyurethane compound having two or more (meth)acryloyl groups in one molecule at a predetermined ratio. It was discovered that it is sufficiently flexible as a protective coating material and has excellent curability, leading to the present invention.

That is, this invention provides a) general formula; CH2=C(R
) -COOR, (R is hydrogen or a methyl group, R1 is a monovalent group having a chain or branched alkyl group having 6 to 18 carbon atoms) 100 parts by weight of liquid monofunctional (meth)acrylate , 1]) 2 to 1.00 overlapping parts of rubber component,
c) Molecular weight 500-20, which has a urethane bond as the main skeleton and has two or more (meth)acryloyl groups in one molecule
,000 polyurethane compound and d
) An optical fiber coating composition characterized in that it contains 0.05 to 30 parts by weight of a polymerization initiator.

The composition of the present invention is less expensive than conventional silicone resins, can be easily cured by light, heat, etc., and has a specific ! J1 sensuality (
By using meth)acrylate, this
Since it has the property of arbitrarily dissolving the rubber component as an ingredient and making it sticky, its viscosity can be adjusted arbitrarily by adjusting the cover of this rubber component, and good painting workability can be obtained according to the painting work conditions. .

In this invention, the liquid monofunctional (meth)acrylate having a chain or branched alkyl group having 6 to 18 carbon atoms includes hexyl (meth)acrylate,
Examples include 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate, which may be used alone or in combination. be done. In particular, when used alone, solid substances are used in combination with liquid substances. Further, those having less than 6 carbon atoms are unsuitable for practical use due to their strong volatility, while those having more than 8 carbon atoms are not preferred because they cause a noticeable decrease in elongation.

These (meth)acrylates having a chain or branched alkyl group highly dissolve various natural or synthetic rubbers or their depolymerized products as component b. The rubber components include natural rubber, imprene rubber, styrene-butadiene rubber (random or block), styrene-isoprene rubber (random or block), butadiene rubber, 20-prene rubber, butyl rubber, polyisobutylene, nitrile rubber, ethylene-propylene rubber, etc. be. Naturally, for example, butadiene-based liquid rubber can also be used.

The amount of these to be used is determined as appropriate to obtain the desired viscosity, and is in the range of 2 to 100 parts by weight per 100 parts by weight of the liquid monofunctional (meth)acrylate. If it is less than 2 parts by weight, the effect of modifying properties or improving flexibility will be insufficient unless a rubber component with a fairly high molecular weight is used, and conversely, if it exceeds 100ffi:i parts, a low molecular weight rubber will be used. In this case, the effect of the rubber component on flexibility is reduced.

Component C, which is used as an essential component in this invention, is used to maintain the curing speed or impart desired softness to the cured product, and has a main skeleton of urethane bonds, and contains two or more in one molecule, usually two or more. A polyurethane compound having ~4 (meth)acryloyl groups, preferably a - group at both ends of the molecule, having an iu of 500 to 20,000 converts the liquid +1 as the 21 components into a functional (meth)acrylate.
It is used at a ratio of 2 to 50 parts by weight per 41 parts by weight of 1 to 100 parts. If it is less than 2 parts by weight, the effect of curing in maintaining the curing speed will be small, and if it exceeds 50 parts by weight, the cured product will become too hard or lose compatibility.
Both are inappropriate.

The compositions of this invention can be easily and quickly cured with radiation such as ultraviolet light by using a photoinitiator as a polymerization initiator for d, Ii, 19 minutes and I. As the above-mentioned photopolymerization initiator, various kinds of initiators and sensitizers that are generally used as initiators and sensitizers for ultraviolet curable coatings can be used. For example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, 2-methylbenzoin, benzophenone, Michler's Katone, benzyl, benzyl dimethyl ketal, benzyl diethyl ketal, anthraquinone, methylanthraquinone, diacetyl, acetophenone, diphenyl disulfide, anthracene. and the like, and those in which these are used in combination with small amounts of sensitizing aids such as amines.

Furthermore, the composition of the present invention can also be cured by heating by using a thermal polymerization initiator instead of or together with the photopolymerization initiator.

Examples of the thermal polymerization initiator include peresters such as tertiary butyl peroctoate and tertiary butyl perpivalate, percarbonate esters such as bis-(4-tertiary butylcyclohexyl)-peroxydicarbonate, and benzoyl peroxide. Diacyl peroxides such as di-tert-butyl peroxide and dicumyl peroxide, hydroperoxides such as cyclohexanone peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, and these together with 2-ethylhexanoic acid and naphthene. Examples include peroxide-based polymerization initiators such as combinations with metal promoters such as cobalt acid salts, and other azo compounds can also be used.

The amount of these photopolymerization initiators and thermal polymerization initiators to be used is as specified in a above.
It should be in the range of 0.05 to 30 parts by weight per 100 parts by weight of liquid monofunctional (meth)acrylate component. 0
．． If the amount is less than 0.5 parts by weight, it will be difficult to initiate sufficient polymerization, while if it is used in an amount exceeding 30 parts by weight, no particular effect will be observed and it will lack practicality, so both are inappropriate.

Polymerizable unsaturated compounds such as (meth)acrylates and other allyl compounds and vinyl compounds other than those mentioned above may be added to the composition of the present invention within an allowable range depending on curing conditions and compatibility. In addition, known thermal polymerization inhibitors are used to improve the thermal stability of the composition, known plasticizers are used to improve the flexibility of the cured product, and soluble agents are used to appropriately adjust the properties during coating. It is possible to add polymeric materials, known anti-aging agents to improve high-temperature deterioration after curing, and improvers to improve adhesion to optical fiber materials.

As described in detail below, the optical fiber coating composition of the present invention comprising the above-mentioned components a to d as essential components can be easily cured by actinic rays such as ultraviolet rays, other type radiation, or heating. Moreover, since the cured product is flexible, it is extremely useful as a protective coating material for optical glass fibers.

EXAMPLES Below, examples of the present invention will be described in more detail.

Example 1 Lauryl tridecyl 7' acrylate as component a (
Styrene-butadiene block copolymer rubber (product name: CALIFLEX TR-, manufactured by Shell Chemical Co., Ltd., manufactured by Shell Chemical Co., Ltd.) as an acid component at the blending ratio (parts by weight) shown in Table 1 to After blending and dissolving urethane acrylate (product name: Viscoat 8, manufactured by Osaka Organic Chemical Industry Co., Ltd.) as component C, average molecular weight Ji5,3
00) at the blending ratio (heavy part) shown in Table 1, the total amount of these blends was made into 100 parts by weight, and to this was added 4 parts of benzyl dimethyl ketal (trade name: Irgacure 651, manufactured by Ciba Geigy) as component d. 'J Ij4. ':”)
1<In addition, four types of optical fiber coating compositions of the present invention were prepared.

The results of examining the viscosity and cured product characteristics of each of these compositions are shown in Table 1 below.

Table 1 The physical properties of the cured product were determined as follows:
Each composition was cast onto a glass plate-H to a thickness of approximately 0.3 ynm, a solution sample was prepared by tightly covering it with a polyester film, and the solution sample was exposed to 400 mJ/ffl using an ultraviolet exposure device equipped with a high-pressure mercury lamp. Create a cured sheet,
A test piece for a tensile test was punched out from this sheet, and a tensile test was conducted at a tensile speed of 50 tnm/min.

Example 2 Isoprene rubber (synthetic imprene rubber IR-10 manufactured by Clarei Soprene Chemical Co., Ltd.) as a component was blended and dissolved in lauryl tridecyl acrylate as component a in the blending ratio shown in Table 2 (parts by weight → 1). Later, more C
Urethane acrylate as a component (same as that in Example 1) was added in the second notation ratio (parts by weight), the total amount of these was set as 100 parts, and benzyl dimethyl ketal as the d component was added in 4 parts by weight. In addition, 3 of this invention
A composition for coating seed optical fibers was prepared.

The viscosity and properties of the cured product were investigated in the same manner as in Example 1, and the results are shown in Table 2 below.

As is clear from the results in Tables 1 and 2 below, the composition of the present invention can be easily adjusted to an appropriate viscosity suitable for coating optical glass fibers/\- as a protective coating. It can be seen that it has a small elastic modulus after curing and has flexibility suitable as a protective coating material for optical glass fibers, and also has good elongation characteristics.

In addition, although Examples 1 and 2 above are all about photocurable products, the present invention was prepared by using Hensil peroxide as a thermal chassis initiator in place of the photopolymerization initiator in each of the above-mentioned compositions. When a thermosetting coating composition was used, the same results as above were obtained in this case as well.

Patent applicant: Nitto Electric Works Shiba Co., Ltd.

Claims (2)

[Claims] (1) a) General formula; CH2=C(R)-COOR,
(R is hydrogen or a methyl group, R1 is a monovalent group having a chain or branched alkyl group having 6 to 18 carbon atoms) 100 parts by weight of liquid monofunctional (meth)acrylate, b) Rubber 2 to 100 parts by weight of components, C) 2 to 50 parts by weight of a polyurethane compound with a molecular weight of 500 to 20,000 having a main skeleton of urethane bonds and two or more (meth)acryloyl groups in one molecule, and d) Polymerization initiator 005
A composition for coating an optical fiber, characterized in that the composition contains 30 parts by weight. (2) The optical fiber coating composition according to claim (+), wherein the polymerization initiator as component d is a photopolymerization initiator and is radiation curable.