JPS6051639A - Composition for covering optical fiber - Google Patents

Abstract

PURPOSE:To provide a titled composition which is soft and excellent in curability, coating workability, and extensibility and consists of specified liquid monofunctional (meth)acrylate, rubber components, monofunctional (meth)acrylate, polyurethanic compds., and a polymerization initiator. CONSTITUTION:2-100pts.wt. rubber components (B) (e.g. butadiene rubber), 10- 80pts.wt. monofunctional (meth)acrylate (C) shown by the formula II (R2 is chain or branched alkyl having 8-18C), 5-50pts.wt. polyurethanic compd. (D) having 500-20,000 molecular weight whose skeleton consists essentially of urethanic coupling and which contains >=2 (meth)acryloyl groups in one molecule, and 0.1- 30pts.wt. thermo- or photopolymerization initiator (e.g. benzoin) (E) are dissolved in 100pts.wt. liquid monofunctional (meth)acrylate (A) shown by the formula I (R is H or methyl, and R1 is a monovalent group having cycloalkyl).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber coating composition useful as a protective coating material 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.

The 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. 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, an inexpensive material that can replace it is desired.

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 (meth)acrylates having cycloalkyl groups dissolve rubber components to a high degree, and by adjusting the amount of this rubber component, it is possible to easily obtain the desired viscosity when coating optical glass fibers. At the same time, a monofunctional (meth)acrylate having a long-chain alkyl group and a specific polyurethane compound having a main skeleton of urethane bonds and having two or more (meth)acryloyl groups in one molecule are added to the rubber component solution. It has been discovered that a curable resin composition obtained by further blending a polymerization initiator with a liquid resin composition in a proportionate amount is sufficiently flexible as a protective coating material for optical glass fibers and has excellent curability, and the present invention has been made based on the present invention. This is what led to this.

That is, this invention provides a) general formula; CI(2=Cr
R) 100 parts by weight of liquid monofunctional (meth)acrylate represented by -COORI (R is hydrogen or a methyl group, R1 is a monovalent group having a cycloalkyl group), b) 2 to 100 parts by weight of rubber component, C ) General formula; CH2=C(R)
-10 to 80 parts by weight of monofunctional (meth)acrylate represented by COOR2 (R is hydrogen or a methyl group, R2 is a chain or branched alkyl group having 8 to 18 carbon atoms), d) urethane bond is the main skeleton Molecular weight 500-20,000 having two or more (meth)acryloyl groups in one molecule
The present invention relates to an optical fiber coating composition comprising 5 to 50 parts by weight of a polyurethane compound and e) 01 to 30 parts by weight of a polymerization initiator.

The composition of the present invention is cheaper than conventional silicone resins, can be easily cured by light, heat, etc., and furthermore, because it uses a specific monofunctional (meth)acrylate as the C component, Since this has the property of arbitrarily dissolving the rubber component as component b, its viscosity can be adjusted arbitrarily by adjusting the amount of this rubber component, resulting in good painting workability depending on the painting work conditions. can get.

In this invention, the liquid monofunctional (meth)acrylate having a cycloalkyl group is practically cyclohexyl (meth)acrylate, inbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, or a cycloalkyl group-containing liquid monofunctional (meth)acrylate having a cycloalkyl group. and (meth)acrylates in which these cycloalkyl groups are linked via a methylene or oxyethylene chain,
These may be used alone or in combination.

These (meth)acrylates having a cycloalkyl group highly dissolve various natural or synthetic rubbers or depolymerized products thereof 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, chloroprene rubber, butyl rubber, polyisobutylene,
Examples include nitrile rubber and ethylene-propylene rubber.

Naturally, for example, butadiene-based liquid rubber can also be used. The amount of these to be used is selected as appropriate to obtain the required viscosity, but 2 parts by weight per 100 parts by weight of the above liquid monofunctional (meth)acrylate.
-100 parts by weight. 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;
If it exceeds 0.00 parts by weight, it is necessary to use a low molecular weight rubber, and in this case, the effect of improving flexibility by the rubber component becomes small.

In the composition of the present invention, the rubber component is dissolved in a monofunctional (meth)acrylate as the C component, and a chain or branched alkyl is added as the C component to mainly modify the initial elastic modulus. The monofunctional (meth)acrylate is blended in a proportion of 10 to 80 parts by weight based on 100 parts by weight of the liquid monofunctional (meth)acrylate. The liquid monofunctional (meth)acrylate as component C is generally a so-called reactive diluent, and its cured product is hard and brittle. For example, in the tensile test of the cured product, the so-called The initial elastic modulus is large, making it completely unsuitable as a protective coating material for optical glass fibers.

In this invention, for the above-mentioned reason, an alkyl monofunctional (meth)acrylate as the C component is an essential component, and this monofunctional (meth)acrylate has a chain or branched alkyl group having 8 to 18 carbon atoms. Specific examples include 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, etc. alone or in mixtures. can be mentioned. If the amount of C component used is less than 10 parts by weight per 100 parts by weight of C component, the effect of modifying the initial elastic modulus will be small, and if it exceeds 80 parts by weight, even if more than this is added, the initial modulus will be improved accordingly. The effect becomes almost unnoticeable.

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 urethane bond as the main skeleton, and contains two or more (meth) bonds in one molecule. A polyurethane compound having an acryloyl group and having a molecular weight of 500 to 20,000 is used in an amount of 5 to 50 parts by weight based on 100 parts by weight of the liquid monofunctional (meth)acrylate as the C component. If the amount is less than 5 parts by weight, the effect on maintaining the curing rate will be small, and if it exceeds 50 parts by weight, the cured product will become too hard or lose compatibility, so both are inappropriate. If the molecular weight is less than 500, it will not be possible to impart flexibility to the cured product, whereas if it exceeds 20,000, it will have difficulty in compatibility with other components. By using a photopolymerization initiator as a polymerization initiator, it can be easily and quickly cured with radiation such as ultraviolet rays.The photopolymerization initiator is generally used as an initiator and sensitizer for ultraviolet curable paints. For example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, pentwinbutyl ether,
- Methylbenzoin, benzophenone, Michler's ketone, benzyl, benzyl dimethyl ketal, benzyl diethyl ketal, anthraquinone, methyl anthraquinone, diacetyl, acetophenone, diphenyl disulfide, anthracene, etc., and those used in combination with small amounts of sensitizing aids such as amines. etc. can be mentioned.

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, dialkyl peroxides such as dicumyl peroxide,
Peroxide-based polymerization initiation, such as hydroperoxides such as cyclohexanone peroxide, methyl ethyl ketone peroxide, and cumene hydroperoxide, and their combinations with metal promoters such as cobal)-II salts of 2-ethylhexanoic acid and naphthenic acid. In addition, other azo compounds can also be used.

The amount of these photopolymerization initiators and thermal polymerization initiators used is as described in C.
The amount should be in the range of 01 to 30 parts by weight based on 100 parts by weight of the liquid monofunctional (meth)acrylate component. 0.
If it is less than 1 part by weight, polymerization cannot be sufficiently initiated, whereas if it is used in excess of 30 parts by weight, no particular effect is observed and it lacks practicality, so both are inappropriate.

Polymerizable unsaturated compounds such as (meth)acrylates other than those mentioned above and other allyl compounds and vinyl compounds may be added to the composition of the present invention within the range permitted in terms of 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 with optical glass fiber materials.

As detailed above, the cured product of the optical glass coating composition of the present invention, which has the a-C component as an essential component, is flexible and therefore extremely useful as a protective coating material for optical glass coatings. be.

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

Example 1 Styrene-butadiene block copolymer comb (component B) was added to cyclohexyl acrylate (product name Viscoat 155, manufactured by Organic Kagaku Kogyo Co., Ltd.) as component C at the blending ratio (parts by weight) shown in Table 1. After blending and dissolving Lauryl tridecyl acrylate (trade name LTA, manufactured by Osaka Organic Chemical Industry Co., Ltd., manufactured by Shell Chemical Co., Ltd.) as the C component, and urethane acrylate (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.) as the C component, Viscoat 812 (trade name, manufactured by Kagaku Kogyo Co., Ltd.; average molecular weight: ft 5300) was added at the blending ratio (parts by weight) shown in Table 1, making the total blended amount 100 parts by weight, and to this was added benzyl dimethyl ketal (Ciba Geigy Co., Ltd.) as component C. Product name Irgacure 65
Four parts by weight of 1) were added to prepare four types of optical fiber coating compositions of the present invention.

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

Table 1 In addition, the physical properties of the cured product were determined as follows. = That is, each composition was cast onto a glass plate to a thickness of about 0.3 am, a solution sample was prepared by closely covering it with a polyester film, and the solution sample was placed in an ultraviolet exposure device equipped with a high-pressure mercury lamp for 24 hours.
00 +11J/';- exposure was performed to create a cured sheet, and tensile test specimens were punched out from this sheet.
The tensile test was conducted at a tensile speed of 50 mm and 1 minute.

Example 2 Styrene-butadiene block copolymer comb as component B was added to inbornyl acrylate (monomer QM-589, manufactured by Rohm & Half Co., Ltd.) as component C in the proportions (parts by weight) shown in Table 2. After blending and dissolving, lauryl tridecyl acrylate as component C and urethane acrylate as component C (trade name: Visco, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 813; average molecular weight 1200
) in the proportions (parts by weight) shown in Table 2, making the total amount of these blends 100 parts by weight, and adding 4 parts by weight of benzyl dimethyl ketal as component C to the four types of optical fiber coatings of this invention. It was made into a composition.

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

Table 2 As is clear from the results in Tables 1 and 2 above,
The composition of the present invention can be easily adjusted to an appropriate viscosity suitable for protective coating of optical glass fibers, has a small elastic modulus after curing, and has flexibility suitable as a protective coating material for optical glass fibers. Moreover, it is found that it also has good elongation properties.

In addition, although Examples 1 and 2 above are all about photocurable products, the thermal polymerization of this invention was performed by using benzoyl peroxide as a thermal polymerization initiator instead of the photopolymerization initiator in each of the above-mentioned compositions. When a curable coating composition was used, the same results as above were obtained in this case as well.

Patent applicant: Nitto Electric Industry Co., Ltd.

Claims (1)

[Claims] fll a) General formula; CH2=C(R)COORt(
R is hydrogen or a methyl group, R□ is a monovalent group having a cycloalkyl group) 100 parts by weight of a liquid monofunctional (meth)acrylate, b) 2 to 100 parts by weight of a rubber component, C) General formula; CI(2=C(R)-COOR2(R
is hydrogen or a methyl group, R2 is a chain or branched alkyl group having 8 to 18 carbon atoms) 10 to 80 parts by weight of a monofunctional (meth)acrylate, d) having urethane bonds as the main skeleton in one molecule. 5 to 50 superimposed parts of a polyurethane compound with a molecular weight of 500 to 20,000 having two or more (meth)acryloyl groups, and e) 0.1 to 30 polymerization initiators.
A composition for coating an optical fiber, comprising parts by weight. (2) The composition for coating an optical fiber according to claim 11, wherein the polymerization initiator as component e comprises a photopolymerization initiator and is radiation curable.