JPS58135157A - Apparatus for coating plastic - Google Patents

Abstract

PURPOSE:The titled apparatus, having plural spiral grooves or fins in a gap formed by a mandrel and a die, and capable of causing a vortex in a liquid plastic flow and forming a coating layer without the uneven distribution on optical fibers, etc. CONSTITUTION:An optical fiber 6 is passed through an opening 6 of a coating apparatus, and a pressurized liquid plastic material is introduced from a resin feed port 3 into the coating apparatus. The plastic material is made to flow in the form of a spiral by grooves 5 formed on the periphery of the mandrel 2 to form a vortex thereof in an opening part 6 of a die 4. The optical fiber is automatically moved to the center of the opening 6 to form a coating layer without the uneven distribution. The automatic centering action of the optical fiber 1 will not cause the contact of the uncoated optical fiber 1 with the opening part 6 of the mandrel 2. The high-speed coating can be carried out by adjusting the feed pressure of the liquid plastic material, and the thickness of the coating layer can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for applying a low viscosity liquid plastic material to a wire rod.

Conventionally, the wire rod has generally been subjected to AM using an extruder. With this method, it is difficult to directly coat a fragile wire such as an optical fiber because it may cause wire breakage to be detected. Matatodan's extruder is designed for thermoplastic resins such as polyethylene, nylon, and vinyl chloride.

Directly coating an optical fiber with this type of plastic has a negative effect on the transmission characteristics due to its large leg ratio ◇Therefore, silicone resin with a low + > df skewer is mainly used in optical fiber devices. 〇 Optical fibers are coated with Shiritsu 4 resin using an open type coating device, so when the linear speed increases, slippage occurs between the fiber and the resin, and the speed is at most 100 g.
/l1inii degree was the limit. Further, there were drawbacks such as a large unevenness in the thickness of the coating layer. Furthermore, in the case of a closed-type 11lliliii device consisting of a mandrel and a cap, the viscosity of the silicone resin is as low as 5000 cps at most, so there are drawbacks such as uneven thickness and easy damage.

In order to eliminate these missing items, the present invention provides fins or grooves in the flow path of the plastic material formed by the cap and the mandrel. The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of the present invention, in which 1 is an optical fiber, 2 is a metal core, δ is a resin supply section, number is a cap, cloud is a groove, and 6 is an opening. To coat using this device, first the optical fiber 1 is run through the opening 6. Subsequently, the pressurized liquid plastic material is caused to flow into the inside of the apparatus from the resin supply port 8. At this time, since the groove 6 is provided on the outer periphery of this mouthpiece, the plastic flows in a spiral shape. Therefore, the plastic forms a vortex at the opening of the cap, and the vortex automatically moves the optical fiber to the center of the opening, thereby forming a coating layer with no uneven thickness. Further, the self-aligning effect of the optical fiber due to the vortex prevents the uncoated optical fiber from coming into contact with the mandrel opening.

Furthermore, by adjusting the supply pressure of the liquid plastic, high-speed filtering is possible and the thickness of the coating layer can be controlled.

The inner diameter of the opening is 0.5-φ1, and the outer diameter of the optical fiber is 12.
When the coating material is a silicone resin with a viscosity of 50,000 p8, coating is possible at a resin supply pressure of 32 to 9/C- and a linear velocity of up to 650 wg/min.
The outer diameter of the coating layer was 875±8μ.

*mt, the breaking strength of the optical fiber is gauge length 10s
In a tensile test of %100 pieces, the minimum was 824 kg/-'', the maximum was 58,819/m'', and the average was 5,211 c9/m''.

Figure 2 shows the grooves on the outer part of the mandrel, where 2 is the mandrel and the container is the groove.

In FIG. 8, fins 7 are provided on the outer periphery of the mandrel instead of grooves.

As explained above, in the plastic coating apparatus of the present invention, a vortex is generated in the flow of liquid plastic by the grooves or fins, and the wire is automatically attracted to the opening by the action of this vortex. Therefore, a coating layer without eccentricity can be obtained. It also has the advantage of being able to coat low-viscosity materials and increasing the linear speed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a diagram showing a grooved mandrel, and FIG. 8 is a diagram showing a finned mandrel. DESCRIPTION OF SYMBOLS 1... Optical fiber, 2... Core metal, 3... Resin supply port, 4... Cap, 5... Groove, 6... Opening, 7...
··fin.

Claims (1)

[Claims] L A device that applies liquid plastic to the wire by passing a wire through an opening that passes through the center of the mandrel and the cap, and applying pressure to the corrugated plastic in the gap formed by the mandrel and the cap. Plastic coating device 0 characterized in that a plurality of spiral grooves or fins are provided in the gap formed.