JP2007140239A - Resin composition for flame-retardant plastic optical fiber coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for a flame-retardant plastic optical fiber coating, the composition having high flame retardant property, high safeness against fire and little influence on an environment and being manufactured in easy processes. <P>SOLUTION: The resin composition for a flame-retardant plastic optical fiber coating comprises 10 to 30 wt.% of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 30 to 50 wt.% and a melt flow rate of 30 to 80 g/10 min, 5 to 20 wt.% of a polyolefin elastomer having a melt flow rate of 0.2 to 1.0 g/10 min, 65 to 80 wt.% of magnesium hydroxide and 1 to 5 wt.% of silicone oil. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flame retardant plastic optical fiber coating resin composition.

  Optical fibers that transmit light include quartz glass and plastic. Quartz glass optical fiber has a very small transmission loss and is widely used for long-distance optical transmission and data transmission. Plastic optical fiber, on the other hand, has a larger transmission loss than quartz glass optical fiber, but it has advantages such as light weight, large diameter, excellent flexibility, easy processing, and low cost. It is used for short-distance transmission such as communication, audio, home appliances and in-car communication. In particular, polymethyl methacrylate (PMMA) is widely used because it is inexpensive and has excellent optical properties.

  The plastic optical fiber has a polymer material such as polymethyl methacrylate (PMMA) and polycarbonate that has good light transmission properties as its core material, and its refractive index is higher than that of core materials such as vinylidene fluoride polymer and perfluoroalkyl methacrylate polymer. It is a concentric type with a sheath polymer (cladding) as a small polymer, and the light incident from one end is transmitted to the other end while being repeatedly reflected by total reflection caused by the difference in refractive index at the interface between the core and cladding. To do.

  The outside of the clad is coated with polyethylene resin, polypropylene resin, polyamide resin, polyvinyl chloride resin, polyacetal resin, etc. to provide heat resistance and strength and protect it from water, chemicals, oxygen, light, etc. However, there is a growing demand for flame retardancy, and there is a need for a flame retardant coating material that does not contain halogen from the standpoint of safety in the event of fire and environmental considerations. Further, since the plastic optical fiber burns itself and drip when in contact with the flame as compared with the non-combustible glass optical fiber, the coating material is required to have particularly high flame resistance.

  Patent Document 1 discloses a resin composition for coating a plastic optical fiber obtained by kneading a polyolefin resin compound obtained by adding and kneading magnesium hydroxide as a flame retardant to a polyolefin resin, a polyamide resin, and a maleated polymer. It is said that the strength does not decrease even under humid conditions, and is excellent in flame retardancy, wear resistance and flexibility.

  However, the resin composition of Patent Document 1 is prepared by previously adding and kneading magnesium hydroxide to produce a polyolefin resin compound, kneading a polyamide resin and a maleated polymer thereto, and imparting sufficient flame retardancy. In this polyamide resin, melamine cyanurate is kneaded as a flame retardant, and the manufacturing cost is inevitable because it is manufactured by a complicated manufacturing process. In addition, cyanide compounds derived from nitrogen-containing compounds such as polyamide and melamine cyanurate may be generated during a fire.

  Patent Document 2 discloses a resin composition for coating a plastic optical fiber containing a metal hydroxide having an average particle size of 2 μm or less as a flame retardant. By using the resin composition as a coating layer, mechanical properties are improved. It is said that a plastic optical fiber having flame retardancy can be provided without lowering. The resin composition for coating a plastic optical fiber has a metal hydroxide content of preferably 35 to 60%, particularly preferably 40 to 50%. If the amount of metal hydroxide added is small, the flame retardancy is poor. It is said that if it is sufficient and too much, the mechanical performance is lowered. However, the addition amount in this range is insufficient to achieve high flame retardancy of V-0 level in the UL-94 test.

JP 2004-53707 A JP 2004-29339 A

  The present invention has been made in view of solving the above-described problems, and has high flame retardancy while having high safety at the time of fire, little impact on the environment, and flame retardant that can be manufactured by a simple process. An object of the present invention is to provide a resin composition for covering an optical plastic optical fiber.

  In order to solve the above problems, the present invention provides an ethylene-vinyl acetate copolymer of 10 to 30% by weight with a vinyl acetate content of 30 to 50% by weight and a melt flow rate of 30 to 80 g / 10 min and a melt flow rate of 0.2. Resin composition for coating a flame retardant plastic optical fiber, comprising 5 to 20% by weight of a polyolefin elastomer of ~ 1.0 g / 10 min, 65 to 80% by weight of magnesium hydroxide and 1 to 5% by weight of silicone oil It is a thing.

  2. The flame retardant plastic optical fiber coating resin according to claim 1, wherein the magnesium hydroxide is magnesium hydroxide having an average particle size of 0.5 to 2 [mu] m treated with a silane coupling agent. It is a composition.

  According to the present invention, a plastic optical fiber having high flame retardancy, sufficient mechanical strength and flexibility without generating a toxic gas containing halogen at the time of combustion such as a fire, and can be processed at a low temperature and has a low melt viscosity. It is possible to provide a resin composition for coating a plastic optical fiber with less mechanical influence on the core and grit at a low cost.

  The plastic optical fiber coating resin composition according to this embodiment will be described. In addition, this embodiment is only one form for implementing this invention, and this invention is not limited by this embodiment.

  The ethylene-vinyl acetate copolymer used in the present invention has a vinyl acetate content of 30 to 50% by weight and a melt flow rate of 30 to 80 g / 10 min. The ethylene-vinyl acetate copolymer is not preferred because the flexibility and flame retardancy are lowered when the vinyl acetate content is less than 30% by weight, and the mechanical strength is lowered when the content exceeds 50% by weight. Further, if the melt flow rate is less than 30 g / 10 min, the flexibility decreases, and if it exceeds 80 g / 10 min, the mechanical strength decreases, which is not preferable.

  As the polyolefin elastomer used in the present invention, a copolymer elastomer of ethylene and an α-olefin having 3 or more carbon atoms is used, and the melt flow rate is preferably 0.2 to 1.0 g / 10 min. When the melt flow rate exceeds 1.0 g / 10 min, not only the flexibility but also the flame retardancy is lowered, which is not preferable. Examples of the α-olefin having 3 or more carbon atoms to be copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. Non-conjugated dienes such as 1,4-hexadiene, dicyclopentadiene, ethylidene norbornene and the like can also be used.

  In this invention, although magnesium hydroxide is used as a flame retardant, the content is 65 to 80 weight% of the resin composition for plastic optical fiber coating. When the content is less than 65% by weight, sufficient flame retardancy is not exhibited, and when it exceeds 80% by weight, mechanical strength and flexibility are insufficient. The magnesium hydroxide is preferably treated with a silane coupling agent. If not treated, the flame retardant effect is lowered and the dispersibility in the resin is also lowered. The average particle size of the magnesium hydroxide is preferably 0.5-2 μm. If the particle diameter exceeds 2 μm, the flame retardance is lowered because the particles are not uniformly and finely dispersed in the resin. The particle size can be measured using a laser type particle size distribution measuring machine, for example, Microtrack manufactured by Nikkiso Co., Ltd.

  The viscosity of the silicone oil used in the present invention is preferably 5000 to 10000 mPa · s. The silicone oil plays a role of providing flame retardancy together with magnesium hydroxide in addition to the role of a lubricant for lowering the viscosity of the resin composition of the present invention. However, when the viscosity is less than 5000 mPa · s, The bleed is increased, and if the viscosity exceeds 10,000 mPa · s, the workability is deteriorated. Moreover, the content is 1 to 5 weight% of the resin composition of this invention. If it is less than 1% by weight, no effect is obtained, and if it exceeds 5% by weight, bleeding occurs as a change over time.

  Content of each said component in the resin composition of this invention is 10-30 weight% of ethylene-vinyl acetate copolymers, 5-20 weight% of polyolefin elastomers, 65-80 weight% of magnesium hydroxide, and silicone oil 1 5% by weight. This content has high flame retardancy, mechanical strength and flexibility, but can be extruded at low temperatures, and the melt viscosity is lowered so that no excessive force is applied to the core and grit of the optical fiber during coating. It is optimized as a blending ratio to make it.

  In addition, the flame retardant plastic optical fiber coating resin composition of the present invention has an antioxidant, a weather resistance improver, an ultraviolet absorber, a colorant, a pigment, a filler, a slip agent, as long as it does not affect its properties. You may add additives, such as an antiblocking agent, an antistatic agent, a crosslinking agent, a flame retardant, an antirust agent, an antibacterial agent, a fragrance | flavor, a plasticizer, and a processing aid.

  The resin composition for coating a flame-retardant plastic optical fiber according to the present invention comprises a biaxial mixture of the above-described ethylene-vinyl acetate copolymer, polyolefin elastomer, magnesium hydroxide, silicone oil and, if necessary, the above additives. It can be easily produced by kneading with a kneader such as an extruder, Banbury mixer or pressure kneader, and granulating with a single screw extruder.

  The optical fiber is coated with the resin composition of the present invention by any conventionally known method, for example, melt extrusion with a single screw extruder or the like, and the melting temperature is 140 ° C. or lower. At this temperature, there is almost no influence on the core resin of the optical fiber such as PMMA, but if it exceeds 140 ° C., the optical fiber may be deformed by heat. Moreover, if the melt viscosity is high, an excessive force is applied to the optical fiber, which may cause damage.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, what is described as a part in an Example and a comparative example represents a weight part.

Example 1
17.08 parts ethylene-vinyl acetate copolymer (Tosoh Corp .: Ultrasen 750) having a vinyl acetate content of 32% by weight and a melt flow rate of 30 g / 10 min (conforming to JIS K-7210), melt flow rate of 0.5 g / 10 min ethylene-octene copolymer (manufactured by DuPont: Engage 8150), 7.32 parts, magnesium hydroxide (manufactured by Sakai Chemical Co., Ltd .: MGZ-1, average particle size 0.8 μm, surface treated with silane coupling 72.50 parts, 3.00 parts of dimethyl silicone oil having a viscosity of 10,000 mPa · s, and 0.10 parts of an antioxidant (Ciba Geigy: IRGANOX 1010) were kneaded in a pressure kneader at 150 ° C. for 10 minutes, Granulation was performed with a single screw extruder to obtain a pellet having a diameter of 3 mm and a length of 3 mm.

Example 2
Except that the ethylene-vinyl acetate copolymer of Example 1 was changed to an ethylene-vinyl acetate copolymer (Tosoh Corporation: Ultrasen 760) having a vinyl acetate content of 42% by weight and a melt flow rate of 70 g / 10 min. In the same manner as in Example 1, a pellet having a diameter of 3 mm and a length of 3 mm was obtained.

Comparative Example 1
Except that the ethylene-vinyl acetate copolymer of Example 1 was changed to an ethylene-vinyl acetate copolymer (Tosoh Corp .: Ultrasen 710) having a vinyl acetate content of 28% by weight and a melt flow rate of 18 g / 10 min. In the same manner as in Example 1, a pellet having a diameter of 3 mm and a length of 3 mm was obtained.

Comparative Example 2
A diameter of 3 mm and a length of 3 mm were obtained in the same manner as in Example 1 except that the polyolefin elastomer of Example 1 was changed to an ethylene-octene copolymer (manufactured by DuPont: Engage 8452) with a melt flow rate of 3.0 g / 10 min. Pellets were obtained.

Comparative Example 3
Except that the magnesium hydroxide of Example 1 was changed to magnesium hydroxide having an average particle size of 0.4 μm (manufactured by Sakai Chemical Co., Ltd .: MGZ-3, the surface was treated with silane coupling), the same procedure as in Example 1 was performed. A pellet having a diameter of 3 mm and a length of 3 mm was obtained.

Comparative Example 4
Pellets having a diameter of 3 mm and a length of 3 mm were obtained in the same manner as in Example 1 except that the silicone oil of Example 1 was changed to dimethyl silicone oil having a viscosity of 4000 mPa · s.

Comparative Example 5
3 mm in diameter and length in the same manner as in Example 1 except that the ethylene-vinyl acetate copolymer of Example 1 was changed to 18.83 parts, the polyolefin elastomer was changed to 8.07 parts, and the dimethyl silicone oil was changed to 0.50 parts. A 3 mm pellet was obtained.

Comparative Example 6
Ethylene-octene copolymer having a vinyl acetate content of 32% by weight and a melt flow rate of 30 g / 10 min (ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation: Ultrasen 750), 25.83 parts, melt flow rate of 0.5 g / 10 min) Combined (manufactured by DuPont: Engage 8150) 11.07 parts, magnesium hydroxide (manufactured by Sakai Chemical Co., Ltd .: MGZ-1, average particle size 0.8 μm, surface treated with silane coupling) 60.00 parts, viscosity After kneading 3.00 parts of 10000 mPa · s dimethyl silicone oil and 0.10 parts of an antioxidant (Ciba Geigy: IRGANOX 1010) at 150 ° C. for 10 minutes with a pressure kneader, the mixture is granulated with a single screw extruder. Thus, a pellet having a diameter of 3 mm and a length of 3 mm was obtained.

Comparative Example 7
39.90 parts of polyethylene (manufactured by Tosoh Corporation; Petrocene 249) having a flow start temperature of 103 ° C., a melt flow rate of 80 g / 10 min and a density of 0.916 g / cm ³ and 60.00 parts of magnesium hydroxide (manufactured by Sakai Chemical Co., Ltd .: MGZ-1, average particle size 0.8 μm, silane coupling treatment), kneaded in a pressure kneader at 150 ° C. for 10 minutes, granulated with a single screw extruder, 3 mm in diameter, length A 3 mm pellet was obtained.

"Evaluation of physical properties of plastic optical fiber coating resin composition"
The resin composition pellets obtained in Examples and Comparative Examples were molded into a sheet by compression molding, and a test piece was prepared from the sheet.

<Flame retardance 1: Vertical combustion test>
A test piece having a length of 125 ± 5 mm, a width of 13 ± 0.5 mm, and a thickness of 2 ± 0.25 mm was prepared, and a vertical compliant with UL-94 V-0 using a UL combustion test chamber HVUL2 manufactured by Toyo Seiki Co., Ltd. The V-0 conformity was determined by a combustion test.

<Flame retardance 2: Oxygen index>
A test piece having a width of 6.5 ± 0.5 mm and a thickness of 3 ± 0.25 mm was prepared and measured according to JIS K7201-2 using an oxygen index measuring device D manufactured by Toyo Seiki Co., Ltd. Above, it was set as the flame retardance pass in the test.

<Melt viscosity>
According to JIS K7199 (capillary die method), a capillary die has an inner diameter of 1 mm, a length of 10 mm, a test temperature of 140 ° C. and measured using a Capillograph PMD-C manufactured by Toyo Seiki Co., Ltd., and a melt viscosity at a shear rate of 12 sec ⁻¹ is 22000 Pa · s or less, and the melt viscosity at 122 sec ⁻¹ was 3000 Pa · s or less.

<Tensile test>
Using No. 2 type test piece, in accordance with JIS K7113 under the conditions of thickness 2mm, marked line 25mm, tensile speed 100mm / min, using Intesco universal material testing machine 201B, tensile yield strength, tensile elongation Was measured.

<Whitening resistance test>
When a 2 mmf load is applied to a 1 mm diameter strand created in melt viscosity measurement, wound around a cylinder with a diameter of 10 mm, and then, when unwound, the presence or absence of white lines is measured by visual confirmation. Is determined to be rejected ×, and the case where there is no pass is determined to be acceptable ○.

  The physical property evaluation results of the above examples and comparative examples are shown in Table 1. According to it, in Examples 1 and 2, the flame retardancy 1 vertical flame test, the flame retardance 2 oxygen index showed excellent flame retardancy, and because it has an appropriate melt viscosity, it has excellent workability, In the whitening resistance test, it can be seen that since the tensile elongation rate is high, the flexibility is excellent, and the tensile yield strength test has an appropriate tensile strength.

  On the other hand, in Comparative Examples 1 to 4, the blending ratio of each component is the same as in the examples, and the types are changed one by one, but the flame retardancy is insufficient or the processability is problematic. It can be seen that it is not suitable as a coating material for plastic optical fibers, such as lack of flexibility.

  In Comparative Example 5, the amount of silicone oil was reduced, but the flame resistance was insufficient due to the small oxygen index (failed), and it was flexible because it failed in the whitening resistance test. It can be seen that there is a lack of sex.

In Comparative Examples 6 and 7, the amount of magnesium hydroxide added was reduced to 60% by weight, but it was found that the flame retardancy was insufficient from both the vertical flame retardant test and the oxygen index. Comparative Example 7 was made with reference to the example of Patent Document 2 described above. In order to increase the dispersibility of the magnesium hydroxide by setting the magnesium hydroxide as a flame retardant to a maximum concentration of 60% by weight as described in Patent Document 2. Despite the silicon coupling treatment, the flame retardancy is inferior and the tensile elongation rate is 0, which is brittle and cannot be molded.

Claims (2)

  Polyolefin elastomer 5 having a vinyl acetate content of 30 to 50% by weight, an ethylene-vinyl acetate copolymer having a melt flow rate of 30 to 80 g / 10 min and a melt flow rate of 0.2 to 1.0 g / 10 min. A flame retardant plastic optical fiber coating resin composition comprising 20% by weight of magnesium hydroxide and 65 to 80% by weight and silicone oil of 1 to 5% by weight.   2. The flame retardant plastic optical fiber coating resin composition according to claim 1, wherein the magnesium hydroxide is magnesium hydroxide having an average particle size of 0.5 to 2 [mu] m treated with a silane coupling agent.