JPS584819A - Cored, high-density fiber and its production - Google Patents

Abstract

PURPOSE:A specific resin for sheathing and another resin containing high-density substance for core are extruded through a double dice into fiber and drawn to produce cored, high-density fiber of high strength. CONSTITUTION:(A) A resin to form the sheath part of conjugate fiber by drawing at a prescribed temperature such as polyethylene and (B) another resin of high-density that is prepared by mixing a high-density powder 3 such as barium oxide with a resin that softens or keeps melting state at the drawing temperature of component A such as modified polyethylene are extruded into conjugate lines having the core of high-density resin 2 covered with the sheath resin 1. Then, the resultant lines are drawn at a prescribed temperature to produce the objective fiber with high-density core covered with high-strength sheath.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing yarn that has sufficient strength and high specific gravity, and conventionally it has been impossible to increase the strength of high specific gravity yarn. However, when the yarn is subjected to Ic stretching treatment to increase its strength, the specific gravity of the yarn itself decreases, as will be described later, and it is inevitable that the yarn will lose its properties as a high specific gravity yarn. The present invention is a novel invention that completely solves the purpose of producing a yarn with high strength and a large specific gravity σ).

Before describing the present invention, the prior art will be briefly described. A method for producing 1 klIll of high specific gravity monofilament by kneading lead monoxide into polyethylene or polypropylene and extrusion molding is described in Japanese Patent Publication No. 47-29876. Although this is disclosed, it is not possible to obtain 1 strength with unrolled yarn. When stretched, voids are created at the front and rear of the powder, and the specific gravity is significantly reduced. Also, in Japanese Patent Publication No. 51-87878,! A method for obtaining heavy weight yarn of polyethylene or polypropylene using Ifi lead wire and metal soap has been disclosed, but 11111! If an attempt is made to obtain a high specific gravity yarn with IIC binding, a large amount of zinc white is dispersed, which weakens the bond between the resins and has the disadvantage that the strength of the monofilament itself rapidly decreases in inverse proportion to the specific gravity.

As a result of various studies, the inventor of the present application has succeeded in producing a 1-weight yarn that has high strength and high specific gravity even when Takanobu is applied.Hereinafter, the present invention will be described.

In the present invention, first, a 2#@ resin, that is, a skin resin of the fiber and a soft resin to be used for the core part, are selected and prepared. It is necessary to have a flowing property. Furthermore, in order to increase the specific gravity of the fibers, a powder of C high specific gravity substance is mixed into the second soft resin and mixed and dispersed to form a high specific gravity resin. The skin resin is likely to be an S1 resin that has the ability to form fibers that can be stretched at a predetermined temperature to improve molecular orientation and increase strength.Now, the soft resin and the skin W resin are extruded using a separate horizontal extruder, and they are mutually extruded. The tip of the extruder enters a two-layer die, which forms a pencil-shaped body in which a high specific gravity resin is wrapped around a core and an outer skin.
The composite filament is hot-stretched under the stretching temperature conditions of the outer skin resin. In this way, the outer skin resin becomes stronger by being stretched over time, but the core height of 4 m Ill does not have long-lasting properties and has rubber-like elasticity at room temperature.
It has adhesion properties and adheres well to powders of high specific gravity substances.

In addition, the outer skin resin softens or melts and flows at 0A degrees when the outer skin resin is extended, and flows in the form of grease.
Because it adapts uniformly to the contraction of the diameter in the horizontal direction and flows, a high specific gravity yarn with little unevenness can be obtained.

In other words, since it is a high-density fiber that is wrapped in an outer skin resin and has a high-density resin encapsulated in the core like a pencil lead, there is no chance that the high-density resin will directly escape to the outside, and this occurs during the Ic extension period during melt flow. Therefore, there are no voids due to high specific gravity powder. That is, what is obtained with 2 klc is an extremely excellent high specific gravity fiber.

Next, the method for producing the high-density fiber of the present invention will be explained in more detail with reference to the drawings. High q as outer skin resin (1)! I! Select ethylene-vinyl acetate copolymer resin as the soft resin (2) for the core, mix it with high specific gravity powder (311C barium sulfate) and mix it with the resin (2) for the core. These two types of resins were put into two extruders prepared in advance, and the resins extruded from the two extruders were introduced into a two-layer die.
The mixed soft resin (2) of 3) is formed into the shape of a pencil lead and expelled from the nozzle hole.
The composite linear body thus formed is cooled and hardened in cooling water to obtain an unrolled yarn. Next, the second cooled and hardened unrolled yarn was heated to 9
Introduced into a hot water path at 8°C, heated for about 7 to 10 minutes.
Do double C training. As shown in Figure 1, the condition of the road is as shown in the unfinished part (B), the extended part (B), and the extended part (C1). When heated, the soft resin (2) in the core melts and flows in the form of grease, and adapts well to shrinkage in the circumferential direction as well as in the vertical direction due to aging, and is proportional to the thinning of the outer skin. The high specific gravity powder (3) is uniformly dispersed in the soft resin during the process of thinning and forming a pencil lead type composite fiber, so when the soft resin (2) melts and flows, the high specific gravity powder (3) has a high specific gravity. The powder flows together and the resin and powder do not separate, and voids due to high specific gravity powder are not created.

In addition, when the soft resin (2) in the core part hardens, the aging period has finished, and the soft resin (2) in the core part remains well adhered to the inside of the outer skin resin (1) after the aging process, so that it becomes hard. Both have good skin contact properties.This is easily understood from the properties of the resin used in the present invention, which will be described later.The specific gravity of the high-density fiber obtained depends on the soft resin of the core ( Although it depends on the increase or decrease in the amount of high specific gravity powder (3) mixed in 2J, the mixing limit B+i should be mixed as much as possible without interfering with the stretching and drawing of the outer skin St fat (1) during melt flow. Needless to say, this is preferable. However, if the amount of resin in the core is increased, the amount of resin in the outer skin will decrease at a certain fineness, which will reduce the strength, so it is necessary to pay attention to this trade-off. be.

As the material of the outer skin resin of the fibers, any type of resin can be used as long as it has abrasive properties, but one with a stretching degree of 9 degrees (1 or more is preferable), so for example, high-density polyethylene,
Polypropylene, polyester, polyamide, etc. are suitable. The soft resin of the core is required to have the following properties.

That is, the outer skin resin itself softens and melts and flows at the temperature of the resin. Good adhesion to the outer skin resin and high specific gravity powder. Even if a considerable amount of high specific gravity powder is mixed in, it has good fluidity. Examples of such conditions include ethylene copolymers, low density polyethylene, modified polyethylene, atactic polypropylene, etc. For high specific gravity powders, various metal oxides, metal oxides such as barium oxide, Zirconiura oxide-km powder,
Although powders such as china clay and calcium carbonate can also be used, zirconium oxide and barium sulfate are particularly preferred. In addition, when extrusion molding the soft resin of the core, it is preferable to knead high-density powder in advance using a Pampari mixer, mixing roll, extruder, etc. to form pellets.

! l! Example A fiber outer skin Si fat (111c) [1alF degree polyethylene (trade name: Hiic JL) was added to the soft resin (2) and ethylene acetate vinyl copolymer resin (trade name: Evaflex)
25 kg of high specific gravity powder (3) was kneaded with 90 kg of barium sulfate with a ratio of t4.4 using a TAV roll to make high specific gravity pellets. The outer skin resin is extruded at 65m/m with L/D28.
1, and for the core resin (2), add the above mixed pellet to L.
/D26 50rn/'m extruder % The tips of the two extruders are connected to each other with a two-layer die, the core resin (2) is covered with the outer skin resin, and a 100 Ho V nozzle is inserted. Spun it into cold water through the hole to make a Suenobujin monofilament, and heated it at 98°CC in a 4ffi long hot bath.
A high specific gravity fiber was obtained by forming a 12.4 m layer in 0-M and 976 times tcg at a speed of 121-m in a 20-th layer. Its physical properties are shown in Table 1, Material 2. For comparison, a seven-no-flament was prepared using high-density polyethylene under the same conditions, and its physical properties are shown in Table 1, Material 1Ic.

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[Brief explanation of drawings]

FIG. 1 is an enlarged longitudinal cross-sectional view of the drawing process of the improved straight fiber of the present invention;
FIG. 2 is an enlarged view of the EK cross section of FIG. 1. Applicant Keigo Matsuki Agent Patent Attorney Takashi Mizuguchi −

Claims (1)

[Scope of Claims] (1) The outer skin is made of a resin that is stretched at a predetermined temperature to improve molecular orientation, and the core is made of a resin that maintains a softened or molten state at the predetermined temperature and contains a high-density substance. A cored high-density fiber obtained by stretching a composite linear body in which a high-density resin obtained by mixing and dispersing powder is encapsulated in a pencil core shape at the predetermined temperature. (2) High-density substance powder is mixed and dispersed in the resin IIk that is polished at a predetermined degree to form the outer skin of the composite fiber and the resin that remains softened or molten at the aging temperature of the A1 resin. A composite linear body is formed by enclosing the high specific gravity resin into the core of the outer skin resin in the shape of a pencil lead through a two-layer die, and this is stretched at the predetermined temperature. A method for producing a cored type high specific gravity fiber, which is characterized by obtaining a fiber in which a resin with a high specific gravity is encapsulated in a core portion of a strong outer skin portion. (3) A method for manufacturing a cored type high-density fiber according to claim 2, in which polyethylene, polypropylene, polyester, polyamide, or a modified product thereof is used as the outer skin resin. (4t #Municipal law for cored high-density fibers according to claim 2 in which modified polyethylene, low-density polyethylene, atactic polypropylene, ethylene copolymer, etc. are used as the core soft resin. (5) High-density substances Claims that use each 'ffi composite powder, composite oxide powder (P14 oxide powder, zirconium oxide powder, oxidizing power ~ sium powder), or inorganic powder such as china clay as the powder. 2. Production method of cored high specific gravity fiber according to item 2.