JPH01190762A - Resin composition for secondary cladding of optical glass fiber - Google Patents

Abstract

PURPOSE:To obtain the title composition which can cure with ultraviolet rays and can give a cladding having a small coefficient of dynamic friction to a spacer unit, by mixing a specified resin component with an oleamide and a photopolymerization initiator. CONSTITUTION:A polyol (a) of an MW of 500-3000 is reacted with a polyisocyanate (b) and an OH-containing acrylate (c) at 50-110 deg.C for 1-20hr to obtain a urethane acrylate. A resin component is obtained by mixing 40-90wt.% said acrylate with 60-10wt.% reactive diluent selected from among N-vinylpyrrolidone, benzyl acrylate, dicyclopentyl acrylate, tricyclodecanedimethanol diacryalte and trimethylolpropane triacryalte. 100 pts.wt. this resin component is mixed with 1-4 pts.wt. oleamide and 0.1-10 pts.wt. photopolymerization initiator to obtain the title composition of a viscosity of 200-20000 cP (at 25 deg.C). After an optical glass fiber is subjected to primary cladding, it is coated with said composition, which is cured by irradiation with ultraviolet rays to obtain a cladding of a coefficient of dynamic friction of 0.12-0.18 to a spacer unit.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a resin composition for secondary coating of optical glass fibers for light transmission, which provides a coating with a small coefficient of dynamic friction on a spacer unit by curing with ultraviolet rays. be.

[Prior art]

The coating of optical glass fibers (hereinafter referred to as optical fibers) used for light transmission usually consists of two layers, an inner layer made of a low Young's modulus material and an outer layer made of a high Young's modulus material. The latter is called a secondary coating.

The secondary coating is used to protect the optical fiber from external influences (stress and water), and conventionally extruded nylon has been used as the secondary coating material.

Recently, there has been a demand for a reduction in the cost of optical fibers, which are transmission media, and various UV-curable resins have been investigated for both secondary coating materials as well as low-cost ultraviolet curable resins that enable high-speed production of optical fibers.

[Problem to be solved by the invention]

Regarding optical fiber structures, single-core wires and 5-core tape core wires are being considered for subscriber use, and 5-core tape core wires are being used for a slot-type 600-core optical fiber cable that is currently under development.

The method for manufacturing slot-type 600-core optical cables is to drop a 5-core tape core wire into a polyethylene spacer unit, but if the coefficient of dynamic friction against the spacer unit is 0.2 or more, the 5-core tape core wire There was a problem that it became difficult to insert the spacer unit into the spacer unit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition for secondary coating of optical fibers that is cured by ultraviolet rays and provides a film with a small coefficient of dynamic friction for a spacer unit.

[Means to solve the problem]

As a composition that achieves the above object, the present invention uses component (A): 40 to 90% by weight of urethane acrylate obtained by reacting a polyol with a molecular weight of 500 to 3,000, a polyisocyanate, and an acrylate having a hydroxyl group. Component (B): 60 to 10% by weight of a reactive diluent selected from N-vinylpyrrolidone, benzyl acrylate, dicyclopentenyl acrylate, tricyclodecane dimethanol diacrylate, and trimethylolpropane triacrylate, and the above component (8). Resin component 10 based on component (B)
Provided is a resin composition for secondary coating of optical glass fibers, characterized in that the resin composition is blended in a ratio of 0 parts by weight to 1 to 4 parts by weight of oleic acid amide and 0.1 to 10 parts by weight of a photopolymerization initiator. do.

In the present invention, polyols having a molecular weight of 500 to 3,000 as raw materials for the urethane acrylate component (A) include the following (a) to (c).

(a) Polyether polyols that are polymers of alkylene oxides having 2 to 4 carbon atoms or copolymers of two or more of these alkylene oxides, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyisobutylene glycol ,
Copolymer of ethylene oxide and propylene oxide, copolymer of tetrahydrofuran and propylene oxide.

(b) Products obtained by adding ethylene oxide or/and propylene oxide to aliphatic amines or polyhydric alcohols, such as amino acids such as ethylenediamine, tetramethylene diamine, hexamethylenecyamine, piperazine, trimethylolpropane, glycerin, etc. An alcohol with ethylene oxide and/or propylene oxide added to it.

(c) Polyester polyols, such as polycaprolactone obtained by ring-opening polymerization of adipic acid and ethylene glycol, diethylene glycol, tetramethylene glycol, hexamethylene glycol, and ε-caprolactone.

These polyols preferably have a molecular weight of 500 to 3,000 in view of Young's modulus at room temperature and elongation at low temperature of a film obtained by curing the composition of the present invention with ultraviolet rays. If the molecular weight is less than 500, the elongation at low temperatures will be less than 5%, resulting in brittleness. Furthermore, if the molecular weight exceeds 3,000, the Young's modulus at room temperature will be less than 4,000 kg/cnt, making it weak against external influences (stress).

Next, as the polyisocyanate as a raw material for component (A), 2.1-)lylene diisocyanate, 2.6-lylene diisocyanate, diphenylmethane-4,4'-diisocyanate, naphthylene-1,5-diisocyanate, xylene diisocyanate , isophorone diisocyanate, 1,6-hexane diisocyanate, trimethylhexamethylene diisocyanate, and mixtures thereof.

Next, examples of the acrylate having a hydroxyl group as a raw material for component (8) include hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropylacrylate, ε-caprolactone-modified hydroxyethyl acrylate, and mixtures thereof. It will be done.

In the urethane acrylate component (A), the hydroxyl group (-OH) of the polyol is the C equivalent, the -NGO group of the polyisocyanate is the b equivalent, and the OH group of the acrylate having a hydroxyl group is the C equivalent. =0.11~
3. It is synthesized by reacting at a ratio of (a+C)/b=1 to 1.2.

As a method for synthesizing urethane acrylate, (1) a method in which a polyol and a polyisocyanate are reacted, and then an acrylate having a hydroxyl group is reacted. (2) a method in which a polyisocyanate and an acrylate having a hydroxyl group are reacted, and then a polyol is reacted; and (3) a method in which a polyol, a polyisocyanate, and an acrylate having a hydroxyl group are simultaneously reacted.
React at ~110°C for 1 to 20 hours as necessary.

When reacting these urethane acrylates, for example, 1
．． An isocyanate reaction catalyst such as 4-diazabicyclo(2,2,2)octane, tin octoate, and dibutyltin dilaurate, and an acryloyl group polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, and phenothiazine may be added.

Next, the reactive diluent of component (B) includes N-vinylpyrrolidone, hensyl acrylate, dicyclopentenyl acrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, and mixtures thereof.

Among these reactive diluents, N-vinylpyrrolidone or hensyl acrylate, dicyclopentenyl acrylate, 1-lycyclodecane dimethanol diacrylate-1
- has a bulky group in the acrylic side chain, so after polymerization it becomes a structure with less freedom due to steric hindrance, forming a cured product with a high Young's modulus. Moreover, Young's modulus can be increased by increasing the crosslinking density of 1-rimethylolpropane triacrylate.

On the other hand, monomers having four or more acryloyl groups in the molecule can increase Young's modulus, but elongation at low temperatures is less than 5%, which is undesirable.

Preferably, N-vinylpyrrolidone having one vinyl group or/and hensyl acrylate or/and dicyclopentenyl acrylate or/and tricyclodecane dimethanol diacrylate having two or more vinyl groups or/and trimethylolpropane triacrylate Preference is given to using acrylates.

The blending ratio of the urethane acrylate as the component (A) and the reactive diluent as the component (B) is 40 to 9, respectively, in the photocurable resin.
0% by weight, preferably 60-10% by weight. (
If the urethane acrylate content of component A) is less than 40% by weight, the elongation at low temperature will be less than 5%, and if it exceeds 90% by weight, the Young's modulus at room temperature will be less than 4,000 kg/cJ, which is not preferable.

In addition to these components (8) and (B), other polymeric resins and reactive diluents may be blended.

Next, oleic acid amide is used as a lubricant that has good compatibility with urethane acrylate and reduces the coefficient of dynamic friction. The present inventors investigated reducing the coefficient of dynamic friction using various lubricants and obtained the following results (a) and (b).

(a) Lubricants that reduce the coefficient of dynamic friction include stearic acid, stearamide, oleic acid amide, amide-modified silicone oil, and methylene bisstearylamide.

(b) Examples of lubricants having good compatibility with urethane acrylate include diphenylformamide, ethyl oleate, chlorinated paraffin, and oleic acid amide.

Oleic acid amide has better compatibility with urethane acrylate than the lubricants (a) and (b) above, and can reduce the coefficient of dynamic friction.

The amount of oleic acid amide used is 1 to 4 parts by weight per 100 parts by weight of the photocurable resin. If the amount used is less than 1 part by weight, the resulting film will have a coefficient of kinetic friction of 0.2 or more, which is not preferable. Moreover, if the amount used exceeds 4 parts by weight, the compatibility with urethane acrylate will be poor and the viscosity will become high, which is not preferable.

Next, as a photopolymerization initiator, hengeine methyl ether, hengeine ethyl ether, benzoin isopropyl ether, hengeine butyl ether, jetoxyacetophenone, benzyl dimethyl ketal, 2-hydroxy-2-methylpropiophenone, 1-hydroxy Mention may be made of cyclohexylphenyl ketone, hendphenone, Michler's ketone, isoamyl N,N-dimethylamino-benzoate, 2-chlorothioxanthone, 2,4-diethylthioxanthone and mixtures thereof.

The amount of these photopolymerization initiators used is 100% of the photocurable resin.
0.1 to 10 parts by weight, preferably 1 to 5 parts by weight
Parts by weight.

The resin composition for optical fiber secondary coating of the present invention is as follows.
In addition to the second component, if necessary, a thermal polymerization inhibitor (hydroquinone, hydroquinone monomethyl ether, henzoquinone, catechol, pt-butylcatechol, phenothiazine, etc.) is used to inhibit polymerization due to heat during storage.
, various additives such as thermoplastic resins (polyurethane resins, polyester resins, acrylic resins, silicone resins), organosilicon compounds, surfactants, etc., which are dissolved in this composition, may be added to improve the physical properties of the coating film. .

The viscosity of this coating resin composition at 25°C is 2.00.
A range of 0 to 20,000 centipoise is preferred from the viewpoint of coatability.

In order to actually coat optical fibers using the resin composition for secondary coating of optical fibers of this invention, conventionally known methods (
JP-A-58-22638, DT2,459,320) can be carried out according to the method of applying the primary coating resin composition to the surface of the optical fiber and polymerizing and curing it by irradiating it with ultraviolet rays. The resin composition for secondary coating may be applied and polymerized and cured by irradiation with ultraviolet rays.

Hereinafter, the present invention will be explained in more detail with reference to urethane acrylate production examples, examples, and comparative examples.

Note that parts in the examples are based on weight unless otherwise noted.

Urethane acrylate production example 75.5 parts of polytetramethylene glycol having a molecular weight of 640, which is a polymer of tetrahydrofuran, and 16.1 parts of isophorone diisocyanate were reacted at 80°C for 2 hours in the presence of 0.02 part of dibutyltin dilaurate. 2
-Hydroxyethyl acrylate-l-8.4 parts and 0.05 part of hydroquinone monomethyl ether were added and further reacted at 80°C for 3 hours to obtain urethane acrylate (this urethane acrylate is referred to as "compound A"). Various urethane acrylates were obtained in the same manner using the formulations shown in Table 1 (hereinafter referred to as "compounds B and C").
and D”. ).

Example 1 70 parts of urethane acrylate "Compound A", 6 parts of N-vinylpyrrolidone, 12 parts of dicyclopentenyl acrylate, 12 parts of tricyclodecane dimethanol diacrylate, 2 parts of oleic acid amide, and 3 parts of benzyl dimethyl ketal. A secondary coating material for optical fibers having a viscosity of 15,000 centipoise (25° C.) was obtained by melting and mixing the following parts.

This coating material was applied to a glass plate to a thickness of 100 μm, and an irradiation device was used with a high-pressure mercury lamp with an output of 2 KW and an output density of 80 W/cm installed perpendicular to the sample passing direction.
Conveyor speed 10m at a position 9cm below the light source
Cured in /min. The physical properties of the obtained film are shown below.

Temperature Young's modulus (kg/c♂do1 Elongation (%) +2
0℃5,20040 -30℃ 14,100 6.
5 Hardness (Shore D) "262 Coefficient of dynamic friction" 30.16 *1: The following Young's modulus is assumed to be 2.5% modulus.

*2: Measured value at 20°C.

*3: Based on ASTM D1894-73 (coefficient of dynamic friction against polyethylene plate).

Optical fiber base material is drawn at a drawing speed of 30 m/min with a diameter of 125 mm.
After spinning into a μm optical fiber, in a process subsequent to the spinning process, 70 parts of urethane acrylate "Compound A" and 30 parts of 2-phenoxyethyl acrylate are dissolved and mixed with 3 parts of henzyl dimethyl ketal to obtain a viscosity of 5. , for 200 centipoise (25°C) optical fiber.
Next, the coating material was applied to the surface of the optical fiber and cured by irradiating it with ultraviolet rays using two high-pressure mercury lamps (output 2 KW, output density 80 W/cm) installed parallel to the drawing direction.

Then, the secondary coating material was further applied and cured by irradiation with ultraviolet rays using two high-pressure mercury lamps.

The outer diameter of the optical fiber after coating is 300 μm of the second coating material.
, the secondary coating material had a thickness of 900 μm, and the surface was uniform.

The obtained optical fiber was easily inserted into the spacer unisoto, and no increase in transmission loss was observed up to -40°C.

Examples 2 to 7, Comparative Examples 1 to 5 In the same manner as in Example 1, physical property values of cured films of resin compositions with the formulations shown in Table 2 and coated optical fibers using these resin compositions were measured at 40°C. Table 2 shows the results regarding the increase in transmission loss.

Although no photopolymerization initiator is listed in the resin composition in Table 2, 3 parts of benzyl dimethyl ketal was used as in Example 1.

〔effect〕

The amount of oleic acid amide used is 0 per 100 parts of resin.
．． In Comparative Example 1 of 5 parts, the compatibility with urethane acrylate was good, but the coefficient of dynamic friction was 0.2 or more. Also,
In Comparative Example 2 in which the amount of oleic acid amide used was 5 parts, the dynamic friction coefficient was less than 0.2, but the compatibility with urethane acrylate was poor.

In Comparative Example 3, in which 2 parts of stearic acid amide was used, the coefficient of dynamic friction was less than 0.2, but the compatibility with urethane acrylate was poor. Further, in Comparative Example 4 in which 2 parts of ethyl oleate was used, the compatibility with urethane acrylate was good, but the coefficient of dynamic friction was 0.2 or more. Furthermore,
Comparative Example 5, in which 2 parts of amide-modified silicone oil was used, had a dynamic friction coefficient of less than 0.2, but had poor compatibility with urethane acrylate.

Claims (1)

[Claims] 1) Component (A): 40 to 90% by weight of urethane acrylate obtained by reacting a polyol with a molecular weight of 500 to 3,000, a polyisocyanate, and an acrylate having a hydroxyl group (Component B) : 60 to 10% by weight of a reactive diluent selected from N-vinylpyrrolidone, benzyl acrylate, dicyclopentenyl acrylate, tricyclodecane dimethanol diacrylate, and trimethylolpropane triacrylate The above (A) component and (B) component Resin component 10 based on
1. A resin composition for secondary coating of optical glass fibers, which is blended in a proportion of 0 parts by weight to 1 to 4 parts by weight of oleic acid amide and 0.1 to 10 parts by weight of a photopolymerization initiator. 2) The viscosity of the coating resin composition at 25°C is 2,00
2. The coating resin composition according to claim 1, wherein the coating resin composition has a particle diameter of 0 to 20,000 centipoise. 3) Coefficient of dynamic friction against the spacer unit is 0.12
The coating resin composition according to claim 1, which is a coating resin composition that provides a coating film of 0.18 to 0.18.