CS264638B1 - A method for producing a quartz polymer optical fiber - Google Patents

Abstract

The method solves the problem of manufacturing an optical fiber of the quartz polymer type with a secondary protection formed by a curable polymer resin. In the manufacturing method, a quartz fiber with a diameter of 100 to 1,000 μm is first pulled out of a quartz rod, a primary layer of a silicone polymer with a thickness of 50 to 100 μm is applied thereto, which is cured at a temperature of 200 to 500 °C. A curable polymer resin with a thickness of 100 to 500 μm is applied as a secondary layer to the primary layer thus formed and cured by UV radiation.

Description

The invention relates to a process for the production of an optical fiber of the quartz polymer type after secondary protection from a UV-curable polymer.

The previously known quartz polymer optical fibers are protected by the primary optical coating, which is most often dimethylpolysiloxane, which, however, is easily damaged due to its low structural strength. It should therefore be protected from mechanical damage by applying an additional layer of polymer that is harder and stronger. This protective layer is usually formed by extrusion-applied thermoplastic during the drawing process or outside the drawing line. Thus, a layer of thermoplastic polymer of polyamide, teflon, polyethylene or polypropylene applied to the fiber provides sufficient mechanical protection to the fiber.

The disadvantage of applying the extrusion secondary protection polymer during fiber drawing, which requires precise alignment of the extrusion operation and the drawing process, is that there are large losses at the beginning of the drawing before the application of the primary and secondary protection can be optimally matched. Applying the secondary protection by the thermoplastic outside the pulling line may lead to an additional increase in the optical loss of the micro-movement caused by the dusting of the primary silicone casing during rewinding.

The above-mentioned disadvantages are eliminated by the method of producing a fiber of the quartz type polymer according to the invention, in which a quartz fiber having a diameter of 100 to 1000 µm is first pulled out of the quartz rod, coated with a primary layer of 50-100 µm silicone polymer. temperature 200 to 500 ° C. SUMMARY OF THE INVENTION The curable polymeric resin having a thickness of 100 to 500 .mu.m is applied to the primary layer as a secondary layer and cured by UV radiation.

An advantage of the process according to the invention is that the secondary protection consisting of a curable polymeric resin can be applied immediately after the application of the primary protection when the fiber is drawn off the drawing line. The prepolymer layer is cured immediately after application with UV light. The mechanical properties of the resin after curing are in the following range: modulus of elasticity 300 to 1500 MPa, elongation 5 to 30 MPa, strength 5 to 40 MPa, glass transition temperature greater than 50 ° C.

A comparison of the relative increase in fiber optic loss with secondary protection of various materials is apparent from the attached drawing, but this is not to be construed as limiting the invention.

The figure shows the relative increase in optical loss curves of PCS-type fiber (200 µm silica diameter, 380 µm silicone sheath diameter) with extrusion coating consisting of Tefzel, westamide (PA 12), polyethylene (PE), dimethylpolysiloxane (Si) and a relative increase in optical loss of the fiber with secondary protection consisting of a UV light-curable resin is shown. The increase in optical loss is monitored as the temperature decreases, with the following curves in the figure: Tefzel curve 2, Westamide curve 2, polyethylene curve 3, UV light curable resin curve 2, and dimethylpolysiloxane curve 2.

The method of manufacture and the properties of the PCS fibers with secondary protection of UV curable polymer resin are illustrated by the examples, which are not intended to limit the invention in any way.

He did

Quartz fiber of a diameter of 200 µm was drawn ^{from a} quartz rod (synthetic silica sprasil F) of 10 mm diameter. The rod was heated in a graphite resistance furnace to a temperature of 2050 ° C. The filament speed controlled by the feedback between the non-contact diameter gauge and the towing device was about 15 m / min. 50 cm below the fiber exit of the graphite resistance furnace, an 80 µm layer of primary polymeric silicone polymer was deposited and cured by passing a 30 cm oven heated to 300 ° C. 20 cm below this curing oven was placed an additional deposition apparatus with epoxy diacrylate prepolymer of 5 Pa.s. A 60 µm epoxy acrylate layer was applied through the nozzle ^and cured by irradiation with 4 RVIF 400 W lamps (manufactured by Tesla Holešovice). After curing, the epoxyacrylate resin had the following properties: elasticity model 1500 MPa, elongation 15%, strength 36 MPa, Tg 58 ° C. The optical fiber drawn from the quartz rod in this way exhibited attenuation at a wavelength of lambda = 810 nm at 20 ° C alpha = = 30 dB / km. When cooled to -40 ° C, the fiber attenuation increased to 41 dB / km. The increase in the attenuation of the PCS fiber with secondary epoxy acrylate resin coating on cooling is lower than that of fibers of the same type with Tefzel, nylon 12, or polyethylene secondary extrusion coating.

Example 2

Quartz fiber of 400 µm diameter was drawn from a quartz rod (Suprasil W1 synthetic quartz) of 14 mm diameter. The rod was heated in a graphite resistance furnace to a temperature of 2050 ° C. The filament speed controlled by the feedback between the contactless meter and the towing device was about 18 m / min. 60 cm below the fiber exit from the graphite resistance furnace, a 60 µm layer of primary protection silicone polymer was deposited and cured by passing a 30 cm oven heated to 270 ° C. 30 cm below this curing oven was placed another deposition device with epoxyacrylate prepolymer viscosity of 4 Pa.s. A 40 µm epoxy-acrylate layer was applied through the nozzle and cured by irradiation with 4 RVI 400 W lamps (manufactured by Tesla Holešovice). After curing, the epoxy acrylate resin had the following properties: elastic modulus of 1035 MPa, elongation 18%, strength 38 MPa, Tg 60 ° C. The extracted fiber was used to transfer power from a 90 W Nd: YAG laser.

Example 3

It was drawn silica fiber diameter 200> im a quartz rod (synthetic quartz Suprasil F) a diameter of 12 _/ um. The rod was heated in a graphite resistance furnace to a temperature of 2050 ° C. The fiber drawing speed regulated by the feedback between the non-contact fiber diameter meter and the towing device was about 30 m / min. A layer of 80 µm primary polymeric protection silicone polymer was applied 1 m below the fiber exit of the graphite resistance furnace and was cured by passing a 60 cm oven heated to 350 ° C. The filament with primary polymer protection was wound on a spool. After the drawing was finished, the fiber spool was placed on the upper platform of the towing device. The fiber was unwound at a speed of 15 m / min. Through the nozzles is a layer of thick epoxiakrylátu 60 _/ um and cured by irradiation with lamps 4 RVI 400 W (manufacturer Tesla Holešovice). The epoxy acrylate resin after curing had the following properties: modulus of elasticity 690 MPa, elongation 30%, strength 28 MPa, Tg 58 ° C.

Claims (1)

A method for producing a fiber of the type quartz polymer with a secondary protective layer, wherein a quartz fiber having a diameter of 100 to 1000 µm is pulled from a quartz rod, and a primary layer of silicone polymer having a thickness of 50 to 100 µm is applied thereto. to a secondary layer, characterized in that a UV-curable prepolymer having a viscosity of 2 to 10 Pa.s, for example an epoxy diacrylate, urethane acrylate or polybutadiene acrylate resin, is applied to the primary layer as a secondary layer. 10 to 500 µm thick and UV cured.