JPS5823913A - Preparation of thermoplastic resin monofilament - Google Patents

Abstract

PURPOSE:To obtain the titled yarns useful for stretching wires in agricultural vinyl greenhouses, without the drawdown of the resin at a low cost, by coating the surface of an extruded thermoplastic resin filamentary material as a core with a molten thermoplastic resin having a relatively narrow melting temperature range. CONSTITUTION:A thermoplastic resin, e.g. polypropylene, as a core is melt kneaded in an extruder, and continuously extruded through a nozzle to give a filamentary material, which is passed through a crosshead die attached to the head of another extruder. A thermoplastic resin, e.g. polyethylene terephthalate, having a relatively narrow melting temperature range is melt extruded through the extruder to apply to and coat the surface of the fialmentary material to prepare a raw filamentary material, which is then drawn to afford the aimed monofilament. Preferably, the filamentary material as the core component is in the state of being taken out at the start to prevent the melting and breaking of the core component by the molten coating component.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a thermoplastic resin monofilament, and more particularly to an easy method for producing a monofilament made of a thermoplastic III resin having a narrow melting point range.

Conventionally, monofilaments made of thermoplastic resins such as nylon and polyethylene tere-2-talate are lightweight and strong, so monofilaments with a diameter of about L8 mm have been widely used as tension wire in agricultural vinyl greenhouses, for example.

However, nylon and polyethylene terephthalate are relatively expensive compared to other thermoplastic resins, and have a sharp melting point, that is, a narrow melting point range. The larger the diameter, the more easily this tendency occurs, making manufacturing difficult and requiring the use of various sophisticated techniques.

・The present invention has been made to solve the above-mentioned drawbacks of the prior art, and its summary is to continuously derive 179 thermoplastic resin linear bodies as core bodies, and to cover the surface thereof. A method for producing a thermoplastic resin monofilament is characterized in that a welded thermoplastic 4il& having a relatively narrow melting point range is extruded and coated to form a raw wire.

Examples of the thermoplastic resin linear body serving as the core in the present invention include those made of thermoplastic resin such as polyethylene, polypropylene, polyvinyl chloride, polyester, etc.
In some cases, materials made of nylon or polyethylene terephthalate may be used. # It is preferred that the linear body be pre-fabricated using conventional process equipment.

In the present invention, the thermoplastic resin with a narrow melting point range to be adhered and coated on the surface of the core body includes nylon, polyethylene terephthalate, etc., which tend to cause drooping at the nozzle outlet in the conventional method, as described in l1f1. can be made. However, the circumstances are different between wire sheathing and monofilament, and monofilament requires a drawing process, so it is not possible to use the normal wire sheathing equipment, so we have to modify or modify the necessary parts experimentally. Must be replenished.

In the case of the manufacturing method of the present invention, if there is a risk that the core will melt in the mold or before it exits the nozzle and enters the cooling process, the passage of the core in the mold may be formed with a heat insulating material. Alternatively, it is preferable to take measures such as connecting the nozzle and the cooling process without leaving any space between them.

In the production method of the present invention, when producing a monofilament made of a thermoplastic resin with a narrow melting point range, the molten resin is coated on the surface of the monofilament as a pre-formed linear body. The core material functions as a kind of carrier, and there is no possibility of drawing. I can do it.

2 In addition, wires with large diameters that could not be formed using conventional nylon resin alone can be manufactured at will, and if a relatively inexpensive thermoplastic synthetic resin is used as the core, the raw wire itself can be made at low cost. Become something.

Example core: polypropylene cm MS-650 manufactured by Yamasoda Co., Ltd.
) was melt-kneaded using an extruder, extruded through a nozzle, and cooled with water to produce a linear body with a diameter of 18 mm.

On the other hand, set the cross to the tip of another extruder 2.
While passing through the front wiring body, polyethylene terephthalate (BVR manufactured by Kijinsha) was extruded and adhered to the surface of the wire body to manufacture a monofilament Kawahara wire with a coating diameter of λ8 mm. The pressing temperature is in the range of about 240 to 260°C, and the melting temperature of Beaupropylene is in the range of about 160 to 170°C, so there is a risk that the polypropylene linear body will melt during coating. However, it is possible to melt and cut the raw wire by continuously drawing out the wire in advance so that there are seven pieces.Next, this raw wire is heated to 105℃ and cut into long A monofilament of 4.18 mm was obtained by stretching 45 times in the direction.The physical properties of the filament were a tensile strength of 211 KF/mm and an elongation of !L3.
-It was.

patent applicant Shikoku Building Blocks Industry Co., Ltd.

Claims (1)

[Claims] L: Thermoplastic resin characterized by continuously deriving a thermoplastic resin linear body as a core, and extruding and adhering a molten thermoplastic resin having a relatively narrow melting point range onto the surface of the core to form a base wire. Method for manufacturing resin monofilament.