JPH0151570B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a composite continuous monofilament having thermal adhesive properties. More specifically, a composite monofilament-like spun product (hereinafter referred to as a composite monofilament) obtained by composite extrusion into a sheath-core mold using a core component resin and a sheath component resin whose melting point is 20°C or more lower than the melting point of the core component resin The present invention relates to a composite continuous monofilament having thermal adhesive properties in which an MF-like spun product) is formed into a continuous structure in a drawing process. Monofilaments, which are generally manufactured using thermoplastic resins such as polyolefin resins as raw materials, have a single-filament structure or multiple single threads arranged in parallel and interconnected, depending on the cross-sectional shape and structure of the die nozzle of the extruder. There are two types, one with a continuous thread structure. In general, monofilaments with a continuous thread structure are easier to operate in secondary processing processes such as weaving, knitting, and twisting, and reduce problems during processing.
Single yarn has the advantage of greatly contributing to streamlining, labor saving, and cost reduction in the next processing process, as well as simplifying operational work by reducing the number of winders in the monofilament manufacturing process. Often used as an alternative to monofilament structures. Usually, composite monofilament with a sheath-core structure (hereinafter referred to as composite monofilament)
It's called MF. ) is produced by using an extruder having a continuous die nozzle with a sheath-core structure. However, in the case of conventional manufacturing of composite continuous yarn MF, there are various requirements for the product specifications of the monofilament obtained, such as changing the number of continuous yarns, ease of unraveling of continuous yarns, or difficulty in unraveling, and it is difficult to meet these demands. In order to achieve this, it is necessary to prepare various die nozzles that match the product specifications, and it is also necessary to stop the manufacturing equipment and replace the die nozzle of the extruder for each required product specification, which reduces equipment costs. The drawback is that there is a lot of waste in terms of productivity. Moreover, the larger the number of continuous yarns in the production of composite continuous yarn MF, the more the composite continuous yarn monofilament-like spun product (hereinafter referred to as composite continuous yarn MF-like spun product).
becomes easily bent or curled at the exit of the die nozzle of the extruder. As a result, spinnability and drawability deteriorate, making it necessary to strictly control extrusion, cooling, take-off, drawing, and other conditions, which inevitably limits the number of continuous yarns, and thus reduces the ability to form composite monofilaments. The disadvantage is that it is extremely difficult to make multiple threads. The present inventors have conducted extensive research in order to solve the above-mentioned drawbacks related to the production of composite continuous yarn MF. As a result, using a resin for the core component and a thermoplastic resin for the sheath component whose melting point is 20°C or more lower than the melting point of the resin for the core component, composite extrusion was carried out using an extruder having a sheath-core type die nozzle. The yarn MF-like spun product is thermally fused to form a continuous yarn in a drawing bath kept at a temperature above the softening point of the resin for the sheath component and below the melting point of the resin for the core component, and is simultaneously drawn to form any continuous yarn structure. The present invention was completed based on the discovery that it is possible to obtain a composite continuous thread MF with a long-lasting structure. As can be seen from the above description, the purpose of the present invention is to
It is an object of the present invention to provide a method for easily and economically producing composite continuous yarn MF having various continuous yarn structures in a drawing step using a composite single yarn MF-shaped spun product. The present invention has the following configuration. (1) A sheath-core composite ratio of 30 obtained by composite extrusion into a sheath-core mold using a thermoplastic resin for the core component and a thermoplastic resin for the sheath component whose melting point is 20°C or more lower than the melting point of the resin for the core component. /70 to 60/40 composite molten monofilament-like spun products are mutually drawn in two or more drawing tanks kept at a temperature higher than the softening point of the resin for the sheath component and lower than the melting point of the resin for the core component of the spun product. 1. A method for producing a composite continuous monofilament having thermal adhesive properties, which comprises forming a continuous structure by heat-sealing and hot stretching. As for the combination of thermoplastic resins used in the present invention, it is necessary to use thermoplastic resins in which the melting point of the resin for the sheath component is 20° C. or more lower than the melting point of the resin for the core component. Other than that, there are no particular restrictions, and the combination of thermoplastic resins used for the sheath-core portion may be the same resin component or a combination of different resin components, but resin components with good compatibility that prevents delamination at the sheath-core interface may be used. A combination of these is preferred. Thermoplastic resins used in the present invention include polyolefin resins such as polyethylene resin (hereinafter referred to as PE), polypropylene resin (hereinafter referred to as PP), polyamide resin, polyvinyl chloride resin, ethylene vinyl acetate copolymer resin, etc. . Additionally, additives added to ordinary thermoplastic resins such as antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents,
Coloring agents, lubricants, matting agents, etc. can be used as necessary. In the composite monofilament according to the present invention, the core component functions to maintain the strength of the monofilament, and the sheath component functions to provide adhesiveness by heat fusion, so the melting point of the resin for the sheath component is lower than the core component. It is better that the melting point is as low as possible than the melting point of the component resin, and the difference in melting point should be 20°C or more. If the melting point difference is less than 20°C, the formation of continuous threads due to heat fusion during drawing will be poor, and the resulting composite continuous threads will be
When MF is woven into a net shape and heat set, the heat set temperature is inevitably close to the melting point of the core component, and a long heat set time is required. As a result, even if it is possible to prevent slippage of the net-like material by heat-setting and adhesion by heat-sealing the mesh portions, the heat during heat-setting causes the orientation of the core components to return to the wide width, resulting in a decrease in strength. Therefore, the strength of the resulting net-like product is undesirably reduced. Further, as the heating device for drawing used in the present invention, a general device used in the production of ordinary monofilaments is sufficient, but a heated air bath or a steam bath is preferable because of its wide temperature control range. Hereinafter, the present invention will be explained using the accompanying drawings. The continuous yarn MF manufacturing method of the present invention involves melt-extruding, cooling and solidifying the composite single yarn MF-like spun product at the entrance of a drawing tank (part 2 in FIG.
As shown in the figure, adjacent single filaments arranged perpendicularly to the drawing direction are maintained in contact with each other and are introduced into a drawing tank and heated and drawn. The monofilament coming out of the drawing tank is drawn by an additional magnification, and a composite continuous yarn MF is obtained in which each single yarn has a desired continuous yarn structure by heat fusion. Further, the temperature of the stretching tank is preferably higher than the softening point of the resin for the sheath component and lower than the melting point of the resin for the core component. If this temperature is below the softening point of the resin for the sheath component, poor stretching and poor thermal fusion between the individual yarns are likely to occur due to differences in the stretching behavior of the resin for the sheath/core component; If it exceeds the above, the heat fusion between the individual filaments is sufficient, but it is difficult to control the degree of heat fusion, and furthermore, the stretching orientation of the core component resin returns, resulting in a decrease in strength, which is not preferable. In addition, in order to obtain the desired number of continuous yarns, as mentioned above, by arranging the desired number of composite single yarn MF-shaped spun products in the direction perpendicular to the drawing direction at the inlet of the drawing tank, it is easy to obtain the desired multi-strand yarn. can be obtained. Further, by adjusting the fineness of the composite single yarn MF-shaped spun product used, it is possible to manufacture composite continuous yarn MF of 100 deniers to several tens of thousands of deniers. When stretching an MF-shaped spun product with a composite structure, the stretching behavior differs depending on each resin component to be composited. Since there is a tendency for the surface layer to become loose and the degree of fusion between each single yarn to vary, it is necessary to select an appropriate stretching ratio depending on each resin component to be composited, but the appropriate range is 5 to 10 times. be. If the stretching ratio is less than 5 times, the resulting monofilament will lack strength due to insufficient stretching. Also, the stretching ratio is 10
If it is more than twice that, it is not preferable because interfacial peeling between the sheath-core resin components, clogging of the surface layer, and variation in the degree of thermal fusion of each MF-shaped spun product will increase. Note that after the stretching step, it is also preferably used to perform a relaxing heat treatment using a general apparatus and method for the purpose of improving the shrinkability of the stretched MF. In the conventionally known method for manufacturing composite thread MF, it is necessary to temporarily stop the equipment and replace the die nozzle of the extruder with a die nozzle that meets the required specifications each time the desired number of threads or the degree of thread adhesion is met. However, with the manufacturing method according to the present invention, it is possible to easily and economically produce composite yarn MF having various degrees of thermal fusion and having any number of yarns without stopping the equipment and using the same die nozzle. It is. The present invention will be explained below with reference to Examples and Comparative Examples. The evaluation criteria and symbols used in Examples and Comparative Examples are as follows. (1) MI: Melt flow index of polyethylene resin.
(according to ASTMD-1238) i.e. temperature 190
The amount of molten polyethylene resin extruded in 10 minutes at ℃ and 2.16 kg load expressed in grams. (2) MFR: Melt flow index of polypropylene resin.
In other words, 10 at a temperature of 230℃ and a load of 2.16Kg.
The amount of molten polypropylene resin extruded per minute expressed in grams. (3) Sheath-core composite ratio: The sheath-core component resin is extruded individually, and the weight ratio of the extruded product per unit time. (4) Spinnability: Condition of extruded product. 〇 indicates normal condition, △ indicates that the spun product is curved at the nozzle exit. (5) Stretchability: Evaluated in stretched state. 〇 indicates no trouble during the stretching process. △ means it becomes curled and troubles tend to occur during the winding process. (6) String forming property: degree of adhesion due to thermal fusion. ○ indicates that the fusion between each single yarn is uniform. △ shows variations in the fusion between each single yarn. (7) Adhesiveness of mesh area: Sensory test by touch. 〇 is sufficiently bonded. △ means the adhesion state is insufficient. Examples 1-2, Comparative Example 1 Core component resin with melting point of 160°C and MFR of 3.5
MFR of PP of g/10 min as resin for sheath component.
7.8g/10min Using PP with a low melting point of 128℃ or using the above-mentioned PP as the resin for the core component, and using the resin for the sheath component with an MFR of 7.8g/10min and a melting point of
Using PP with a low melting point of 134℃, extruder 2 with a diameter of 40mm
Melt extrusion using a sheath-core type nozzle with a circular hole of 1.5 mm in diameter on the stand, cooling, composite ratio 50/50, fineness 3200.
A denier sheath-core type composite single yarn MF-shaped spun product was obtained.
Subsequently, using the separation bar 2 set at the inlet of the drawing tank shown in FIG. 1, the composite single fiber MF-shaped spun product 1 is set in sets of five fibers as shown in FIG. While the composite single fiber MF-shaped spun product 1 is kept in contact with each other, the temperature is increased to 130°C.
The film was introduced into a steam heating bath 3 adjusted to a temperature of 1, and was stretched at a stretching ratio of 8 times. As a result, there is no peeling between the sheath and core component resins, and each single yarn has a five-strand structure due to heat fusion.The result is a composite five-strand yarn with a fineness of 2000 denier.
MF4 was obtained. Furthermore, using the composite 5-strand MF made by the above method, the weaving density is 5 yarns/25mm vertically and 5 yarns/25mm horizontally.
After weaving it into a net shape, it was heat set in a hot air heating tank at 140° C. for 1.5 minutes to obtain a net-like product in which the mesh portions were bonded by heat fusion and were resistant to sagging. In addition, as Comparative Example 1, the core component resin had a melting point of 160.
℃, MFR 3.5g/10 minutes PP is used, and the resin for the sheath component has a melting point of 141℃, MFR 8.0g/10 minutes low melting point PP.
5 composite yarns in the same manner as in Examples 1 and 2 using
MF was produced, woven into a net shape in the same manner as in Examples 1 and 2, and then heat set for 1.5 minutes to obtain a net-like product. Spinnability, stretchability,
The continuous thread formation property and mesh area adhesion were observed and evaluated. The results are shown in Table 1. Examples 3 to 5, Comparative Examples 2 to 3 Melting point 160°C, MFR 3.5g/ as core component resin
Using 10-minute PP, the melting point is 128 as the resin for the sheath component.
℃, MI 16.1 g/10 min using high-density PE under the same conditions as Examples 1 and 2, with sheath-core composite ratios of 30/70 and 50/50.
Various types of sheath-core type composite single yarn MF-shaped spun products were obtained. Subsequently, using the separation bar 2 set at the inlet of the drawing tank as shown in FIG. Using the same conditions and method as in Examples 1 and 2, a composite 10-strand MF with a fineness of 4000 denier and no peeling between the sheath and core component resins was obtained. Using this composite 10-strand MF, it was woven into a net shape in the same manner as in Examples 1 and 2, and heat set in the same manner as in Examples 1 and 2, so that the mesh portions were heat-sealed, resulting in a net that was difficult to cause mesh sagging. I got something like that. In addition, as Comparative Examples 2 to 3, the same resins as in Examples 3 to 5 were used for the core component resin and the sheath component resin, respectively, and the sheath-core composite ratio was
Sheath-core type composite single yarn MF-shaped spun products with a fineness of 3200 denier and 25/75 and 65/35 were obtained. The obtained composite single yarn MF-shaped spun product was drawn under the same conditions and method as in Examples 3 to 5 to obtain a composite 10-strand MF having a fineness of 3200 deniers. Examples 1 to 2 using this composite 10-strand MF
It was woven into a net-like material in the same manner as in Example 1 and 2, and heat-set in the same manner as in Examples 1 and 2 to obtain a net-like material. Spinnability, stretchability,
The continuous thread forming property and mesh area adhesion were observed and evaluated.
The results are shown in Table 2. Example 6 As core component resin, melting point 160℃, MFR 3.5g/
Using 10-minute PP, the melting point is 90℃ as the resin for the sheath component.
MI12g/10min low density PE70 parts by weight and ethylene vinyl acetate copolymer resin 30 with vinyl acetate content 15% by weight
A sheath-core type composite single yarn MF-shaped spun product having a sheath-core composite ratio of 50/50 and a fineness of 3200 denier was obtained under the same conditions as in Examples 1 and 2 using the mixture in the following parts by weight. The resulting composite spun product was heated for 20 minutes using a separation bar 2 set at the inlet of the drawing and heating tank shown in Fig. 1.
20 composite yarns with a fineness of 8,000 denier and no peeling between the sheath and core component resins, arranged as one set so as to be adjacent to each other in the vertical direction of the spun product, using the same conditions and method as in Examples 1 and 2. Got MF. This composite 20-strand MF is woven into a net shape in the same manner as in Examples 1 and 2, and heat set in the same manner as in Examples 1 and 2, so that the mesh portions are heat-sealed and do not easily sag. A net-like substance was obtained.

[Table] Minutes

[Table] As can be seen from Table 1, the closer the melting point of the resin for the sheath component is to the melting point of the resin for the core component, the worse the continuous thread forming property and the adhesiveness of the network portion. From this, it was found that the melting point difference between the resins for the sheath and core components must be 20°C or more. Also, from Table 2, as in Comparative Example 2, the sheath-core composite ratio
In the case of 25/75, it was found that the spinnability, continuous yarn forming property, and network part adhesion deteriorated, and when the composite ratio was 65/35 as in Comparative Example 3, the spinnability and stretchability deteriorated. Sheath-core composite ratio is 30/70 to 60/40
It has been found that it is preferable to fall within the range of . As shown in Example 6, it was confirmed that the manufacturing method according to the present invention can easily produce a monofilament having a multi-thread structure such as 20 threads. As described above, in the method for manufacturing composite continuous thread MF according to the present invention, unlike conventionally known methods, the device is stopped for each required number of continuous threads or degree of continuous thread adhesion, and the die nozzle of the extruder is adjusted according to the required specification. It has been found that there is no need to change the die nozzle, and it is possible to easily and economically produce composite yarn MF of the desired specifications using the same die nozzle.

[Brief explanation of drawings]

FIG. 1 shows a side view of the stretching device. FIG. 2 shows a sectional view of the inlet of the drawing tank. (Cross-sectional view of the part 2 in Fig. 1) Fig. 3 is a cross-sectional view of the composite single fiber MF-shaped spun products arranged at the inlet of the drawing tank, and a cross-sectional view of the composite continuous thread MF produced by drawing and heating. In case of 5 consecutive threads). In addition, the numbers in the figure represent the following. 1... Composite single yarn MF-shaped spun product, 1a... Sheath component, 1b... Core component, 2... Separation bar, 3... Drawing tank (steam heating bath), 4... Composite 5-strand MF , 4
a... Sheath component, 4b... Core component.

Claims (1)

[Scope of Claims] 1. A sheath obtained by composite extrusion into a sheath-core type using a thermoplastic resin for a core component and a thermoplastic resin for a sheath component whose melting point is 20°C or more lower than the melting point of the resin for the core component. Stretching of a composite molten monofilament-like spun product with a core composite ratio of 30/70 to 60/40 while maintaining the temperature above the softening point of the resin for the sheath component of the spun product and below the melting point of the resin for the core component. A method for producing a composite continuous monofilament having thermal adhesive properties, which comprises forming a continuous structure by heat-sealing and hot-stretching two or more filaments together in a bath. 2. The composite continuous yarn monomer according to claim 1, wherein the resin for the sheath component is an ethylene-propylene copolymer or an ethylene-propylene-butene terpolymer, and the resin for the core component is a polypropylene homopolymer. Method of manufacturing filament. 3. The method for producing a composite continuous monofilament according to claim 1, wherein the resin for the sheath component is a polyethylene resin or a mixture of a polyethylene resin and an ethylene/vinyl acetate copolymer resin, and the resin for the core component is a polypropylene resin. .