JP6836765B2 - Method for manufacturing drawn multifilament yarn - Google Patents

Description

The present invention relates to a method for producing a drawn multifilament yarn, and more particularly to a method for producing a drawn multifilament yarn used for obtaining a reinforcing cloth for reinforcing a container by adhering it to a wall of a resin container.

Conventionally, the container is reinforced by adhering the cloth to the outside or the inside of the wall of the resin container or inserting the cloth into the wall. As the reinforcing cloth, a woven fabric, a knitted fabric, a multi-axis sheet, or the like is used. As a thread constituting such a reinforcing cloth, a thread made of a core-sheath type composite fiber may be used. The core-sheath type composite fiber is one in which the core component is made of a high melting point polymer and the sheath component is made of a low melting point polymer. Then, since only the sheath component can be softened or melted and fused to the wall of the resin container, it is used as a constituent fiber of the reinforcing cloth.

High melting point polymers such as polyamide, polyester, polyolefin, polyurethane, polycarbonate, acrylic, polyphenylene ether and polyvinyl alcohol are used as the core component of the core-sheath type composite fiber, and polyethylene, polypropylene and ethylene are used as the sheath component. -Low melting point polymers such as propylene-based copolymers are used (Patent Document 1, Claims 1 to 3). That is, it is known that various polymers can be used as the core component as long as it is a high melting point polymer, and an olefin polymer having good compatibility with the resin and excellent adhesiveness is used as the sheath component.

Such core-sheath type composite fibers are required to have high strength. In particular, high strength is required for the core component that remains in the fiber form after being adhered to the wall of the resin container. The present inventor has attempted to adopt polyamide MXD6 having high strength and high rigidity as a core component. However, since polyamide MXD6 is inferior in spinnability, it has been difficult to obtain a core-sheath type composite fiber having a uniform fineness. Further, in order to improve the strength of the core-sheath type composite fiber, when the drawing treatment is performed, the core component and the sheath component may be peeled off, and weaving or knitting using a thread made of the core-sheath type composite fiber, etc. There is a drawback that it becomes difficult for the sheath component to be uniformly present in the fabric because the sheath component is detached or cut during the process. Further, even if the core-sheath type composite fiber in which the core component and the sheath component are peeled off is adhered to the wall of a container or the like, there is a drawback that strong adhesion cannot be realized.

Japanese Unexamined Patent Publication No. 2003-193332

An object of the present invention is to provide a method for producing a drawn multifilament yarn having a uniform fineness and a core component and a sheath component that are difficult to peel off, while adopting a polyamide MXD6 as a core component of a core-sheath type composite fiber. There is.

The present invention solves the above problems by using a specific polymer that imparts spinnability to polyamide MXD6 as a sheath component. That is, in the present invention, a multifilament yarn made of a core-sheath type composite long fiber having a core component made of polyamide MXD6 and a sheath component made of maleic acid-modified polyolefin is obtained by a composite melt spinning method, and then the multifilament yarn is cooled. The present invention relates to a method for producing a drawn multifilament yarn, which comprises performing a drawing treatment under heating.

First, polyamide MXD6 as a core component is prepared. Polyamide MXD6 is a polyamide obtained by polycondensation reaction of methylylenediamine and adipic acid. The melting point of polyamide MXD6 is about 240 ° C. By using polyamide MXD6 as the core component, a core component having high strength and high rigidity can be obtained. In addition, only polyamide MXD6 may be used as a core component, or may be mixed with another polymer and used as a core component. On the other hand, a maleic acid-modified polyolefin as a sheath component is prepared. The maleic acid-modified polyolefin is obtained by adding maleic acid (including maleic anhydride) to the side chain of the polyolefin. As the maleic acid-modified polyolefin, maleic acid-modified polyethylene or maleic acid-modified polypropylene can be used. The melting point of the maleic acid-modified polyolefin varies depending on the type, but is generally 110 to 160 ° C., which is lower than the melting point of the polyamide MXD6. By using maleic acid-modified polyolefin as the sheath component, the spinnability of the polyamide MXD6, which is the core component, can be improved. Although the reason for this is not clear, it is considered that the polyamide MXD6 firmly adheres to the maleic acid-modified polyolefin, and the good spinnability of the maleic acid-modified polyolefin helps to improve the spinnability of the polyamide MXD6.

An unmodified polyolefin may be added to the maleic acid-modified polyolefin as a sheath component. As such polyolefin, high density polyethylene, low density polyethylene or polypropylene can be used. The amount of the unmodified polyolefin added is about 50 to 150 parts by mass with respect to 100 parts by weight of the maleic acid-modified polyolefin. The reason for adding the unmodified polyolefin is to adjust the melt flow rate of the sheath component to improve its spinnability and fluidity, and to facilitate composite melt spinning.

A method in which a core component and a sheath component are introduced into a spinning apparatus provided with a plurality of composite melt spinning holes in a molten state, and the core component and the sheath component are discharged from the heated composite melt spinning hole (that is, a composite melt spinning method). ) To obtain a core-sheath type composite long fiber. A multifilament yarn is obtained by aligning each core-sheath type composite long fiber obtained from each composite molten spinning hole. In order to continuously discharge the core component and the sheath component from the composite melt spinning hole and to cover the core component well with the sheath component, it is preferable to adjust the melt flow rate of the core component and the sheath component within a certain range. .. Specifically, the melt flow rate of the core component should be in the range of 5 to 40 g / 10 minutes, and the melt flow rate of the sheath component should be in the range of 15 to 65 g / 10 minutes. In particular, within this range, it is preferable that the melt flow rate of the sheath component is higher than the melt flow rate of the core component to increase the fluidity of the sheath component. The melt flow rate was measured at 270 ° C., which is a temperature close to the temperature at the time of composite melt spinning, with a load of 2.16 kg.

The resulting multifilament yarn is cooled and wound up. Further, after cooling, an oil agent may be applied to the multifilament yarn. By adding an oil agent, it is possible to improve the take-up property, the rewind property, the weaving property, the knitting and knitting property, and the like. After cooling, the multifilament yarn is drawn under heating to obtain a drawn multifilament yarn. Examples of the heating method include a method of blowing superheated steam on the multifilament yarn and a method of blowing hot air. The heating temperature is preferably a temperature that promotes crystallization of the core component, and is about 150 to 250 ° C. Of course, even if superheated steam or hot air is blown onto the multifilament yarn, the temperature of the multifilament yarn does not immediately reach the temperature of the superheated steam or hot air, so it is preferable to blow the superheated steam or hot air at a temperature of 300 ° C. or higher. .. Stretching is performed between two pairs of rollers. For example, after introducing the multifilament yarn between the pair of first rollers heated to about 100 ° C., the multifilament yarn is introduced between the pair of heated second rollers having a rotation speed faster than that of the first roller. It is done by. By providing a difference in rotation speed between the first roller and the second roller, it is possible to stretch at an arbitrary magnification. For example, when the rotation speed of the first roller is X rpm and the rotation speed of the second roller is 2 X rpm, the drawing is performed at a stretching ratio of 2 times. In the present invention, the draw ratio is preferably 3 to 7 times, and most preferably 4 to 6 times.

According to the present invention, a drawn multifilament yarn in which the core component and the sheath component are in close contact with each other and the core component and the sheath component are less peeled off can be obtained even through the above-mentioned drawing step. In the drawn multifilament yarn, the fineness of the core-sheath type composite long fibers is about 3 to 10 decitex, and the number of core-sheath type composite long fibers is about 100 to 300. Therefore, the total fineness of the drawn multifilament yarn is about 500 to 3000 decitex. A fabric is obtained using this drawn multifilament yarn. Specifically, a drawn multifilament yarn is used as a warp yarn and a weft yarn and woven to obtain a woven fabric. As the structure of the woven fabric, a conventionally known structure such as a plain weave structure, a twill weave structure, or a satin weave structure may be adopted. Further, a knitted fabric is obtained by knitting by weft knitting or warp knitting using a drawn multifilament yarn. As the knitted structure, a conventionally known structure such as a flat knitted structure, a pearl knitted structure, or a tricot knitted structure may be adopted. Further, layers in which drawn multifilament yarns are arranged in a warp direction, an oblique direction, or a weft direction are laminated to obtain a multi-axis sheet formed by adhering each layer. Since the yarns constituting these fabrics are made of core-sheath type composite long fibers, even if only the sheath component is softened or melted and the yarns are fused between the yarns to prevent the occurrence of misalignment. Good. Of course, the core-sheath type composite long fibers constituting each yarn may also be fused to impart rigidity to the fabric.

The fabric obtained by the above method is used as a reinforcing fabric for various materials. For example, it can be stretched on the surface of the wall of a resin container, heated and pressurized, and only the sheath component of the core-sheath type composite long fiber is softened or melted and adhered to reinforce the wall of the resin container. ..

When the method according to the present invention is adopted, since the polyamide MXD6 is given good spinnability, it is possible to obtain a core-sheath type composite long fiber having a uniform fineness. In addition, it is possible to obtain a core-sheath type composite long fiber with less peeling of the sheath component from the core component. Therefore, there is an effect that a drawn multifilament yarn made of constituent fibers having uniform fineness and less peeling between the core component and the sheath component can be obtained. Further, when a cloth is obtained by using a core-sheath type composite long fiber in which the core component and the sheath component are less peeled off, the sheath component is uniformly present in the cloth. When only the sheath component in the fabric is softened or melted and adhered to the wall of the resin container or the like, uniform and strong adhesion can be realized, and the effect of reinforcing the wall contact of the resin container is excellent. Play.

Example 1
As a core component, polyamide MXD6 having a melting point of 240 ° C. and a melt flow rate of 16.1 g / 10 minutes was prepared. The following mixed resin was prepared as a sheath component. That is, 40 parts by weight of low-density polyethylene having a melting point of 127 ° C. and a melt flow rate of 12.0 g / 10 minutes and 60 parts by weight of maleic acid-modified polyethylene having a melting point of 122 ° C. and a melt flow rate of 25.9 g / 10 minutes. A uniformly mixed mixed resin was prepared. Then, a core-sheath type composite spinning base with a hole diameter of 0.5 mm and 192 holes is attached to the composite melt spinning apparatus so that the core component: sheath component = 2: 1 (weight ratio) at the base temperature of 280 ° C. Both were supplied, and 192 core-sheath type composite long fibers were spun. After that, it was passed through a heating cylinder having a length of 20 cm at a temperature of 300 ° C. provided directly under the spinneret, and then cold air having a temperature of 16 ° C. and a speed of 0.8 m / sec was blown using a horizontal cooling device. The core-sheath type composite long fiber was cooled. After cooling, an oil agent was applied to the surface of the core-sheath type composite long fibers, and a multifilament yarn in which 192 core-sheath type composite long fibers were aligned was wound by a take-up roller.

The multifilament yarn was unwound from the take-up roller and introduced into a pair of first rollers heated to 105 ° C., and then further introduced into a pair of second rollers heated to 100 ° C. A steam treatment machine was used between the first roller and the second roller to blow superheated steam at a temperature of 350 ° C. and a pressure of 0.2 MPa onto the multifilament yarn, and the yarn was stretched at a draw ratio of 4.4 times. After drawing, a relaxation treatment and a relaxation treatment were carried out by a conventional method to obtain a drawn multifilament yarn of 830 decitex / 192 filaments.

Example 2
The mixed resin used as a sheath component is 40 parts by weight of high-density polyethylene having a melting point of 131 ° C. and a melt flow rate of 56.5 g / 10 minutes, and malein having a melting point of 122 ° C. and a melt flow rate of 25.9 g / 10 minutes. A drawn multifilament yarn was obtained under the same conditions as in Example 1 except that 60 parts by weight of the acid-modified polyethylene was changed to a uniformly mixed resin.

Comparative Example 1
Stretched multifilament yarn by the same method as in Example 1 except that 100 parts by weight of low-density polyethylene having a melting point of 127 ° C. and a melt flow rate of 12.0 g / 10 minutes is used instead of the mixed resin used as the sheath component. Got

The sheath components of the drawn multifilament yarns obtained in Example 1 and Comparative Example 1 were softened to lightly fuse the core-sheath type composite long fibers with each other, and then the drawn multifilament was cut to obtain the drawn multifilament. The cross section was observed with an optical microscope. The stretched multifilament of Example 1 is shown in FIG. 1, and the one of Comparative Example 1 is shown in FIG. As is clear from the comparison between FIGS. 1 and 2, the core-sheath type composite long fibers constituting the drawn multifilament yarn obtained in Example 1 have uniform fineness and almost all core components and sheath components. While the core-sheath type composite long fibers obtained in Comparative Example 1 were not peeled off, the fineness was non-uniform and the peeling between the core component and the sheath component was remarkable.

A plain weave woven fabric was woven using the drawn multifilament yarns obtained in the examples as warp yarns and weft yarns, and the woven fabric was firmly attached to the wall of the resin container by heating and pressurizing the woven fabric. It adhered and could be suitably used as a reinforcing cloth.

It is a photograph when the cross section of the drawn multifilament yarn obtained in Example 1 was observed with an optical microscope. It is a photograph when the cross section of the drawn multifilament yarn obtained in Comparative Example 1 was observed with an optical microscope.

Claims (5)

A multifilament yarn made of a core-sheath type composite long fiber having a core component made of polyamide MXD6 and a sheath component made of maleic acid-modified polyolefin is obtained by a composite melt spinning method, and then the multifilament yarn is cooled and then heated. A method for producing a drawn multifilament yarn, which comprises performing a drawing treatment. The method for producing a drawn multifilament yarn according to claim 1, wherein high-density polyethylene is added to the sheath component. A method for producing a fabric, which is obtained by using the drawn multifilament yarn obtained by the method according to claim 1. A method for producing a woven fabric in which the drawn multifilament yarn obtained by the method according to claim 1 is used as a warp yarn and a weft yarn. A method for producing a reinforcing fabric, wherein the fabric obtained by the method according to claim 3 is heat-treated to soften or melt only the sheath component to fuse the drawn multifilament yarns constituting the fabric.