JP2008075204A - Thermobondable filament - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermobondable filament of a core-sheath type composite fiber, enabling the rigidity of a molded product obtained after melting the sheath component to be improved. <P>SOLUTION: The thermobondable filament is the core-sheath type composite fiber constituted of a core component consisting essentially of a polyethylene terephthalate, and a sheath component consisting essentially of a copolyester having the melting point lower than that of the core component. The mass ratio (core:sheath) of the core to the sheath is (4:1) to (7:1), the tensile strength is ≥3.5 cN/dtex, and the elongation is ≤30%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat-bondable continuous fiber suitable for obtaining industrial materials and household materials such as mesh sheets, nets and ropes.

  Conventionally, processing is performed using a resin such as a vinyl chloride resin in applications where fixing of intersections of fibers constituting a mesh sheet or the like and water permeability such as a tarpaulin fabric are regarded as important.

  However, in recent years, vinyl chloride resins and the like have been considered to have a problem of influence on the environment, and processing methods that do not perform resin processing have been studied.

  As one of them, core-sheath polyester heat-bondable continuous fibers whose sheath is a low-melting-point component and ordinary polyester fiber are used for knitting and weaving and then heat treatment to melt or soften the low-melting-point component. In addition, a mesh sheet with a fixed intersection portion, a net with a fixed mesh shape, and the like have been proposed (for example, see Patent Documents 1 to 3).

  Moreover, a molded article can also be obtained using only heat-bondable long fibers. That is, since the heat-bondable long fiber is fibrous, it has flexibility before melting the sheath component and is easy to mold. When the sheath component is melted, the single yarns constituting the multifilament are bonded to form a monofilament, so that a molded product having excellent rigidity can be obtained.

  In this way, when molding with heat-adhesive long fibers and other general yarns, when molding with only thermo-adhesive fibers, and when obtaining highly rigid molded products, the thermal adhesive used Although it is possible to improve the rigidity by increasing the fineness of the long fibers, it is disadvantageous in terms of weight reduction and cost.

Therefore, there has been a demand for a heat-bondable long fiber that can improve the rigidity of the molded product without changing the fineness and amount of the heat-bondable long fiber.
JP 2001-271245 A JP 2001-271270 A JP 2001-214388 A

  This invention makes it a technical subject to solve the above-mentioned problems and to provide a heat-bondable long fiber that can improve the rigidity of a molded product obtained after melting the sheath component. is there.

  As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.

  That is, the present invention is a core-sheath type composite fiber composed of a core component mainly composed of polyethylene terephthalate and a sheath component mainly composed of a copolyester having a melting point lower than that of the core component, and the core-sheath mass The gist is a heat-adhesive long fiber characterized by a ratio (core: sheath) of 4: 1 to 7: 1, a tensile strength of 3.5 cN / dtex or more, and an elongation of 30% or less. is there.

  The heat-bondable continuous fiber of the present invention can improve the rigidity of a molded product obtained after melting the sheath component, so when obtaining various molded products including mesh sheets, nets, molded rods, etc. Can be suitably used.

  Hereinafter, the present invention will be described in detail.

  The heat-bondable continuous fiber of the present invention is formed by melting a sheath component and requires high adhesive strength and rigidity. Also, in order to obtain good yarn-making properties, the fiber cross-sectional shape has a core-sheath structure in which the core component is a reinforcing component and the sheath component is an adhesive component.

  First, the core component will be described. The main component of the core component is polyethylene terephthalate (hereinafter referred to as PET), which is inexpensive, excellent in weather resistance and dimensional stability, and excellent in rigidity among polyesters.

  In the core component, the third component may be added and copolymerized to such an extent that the performance of PET is not impaired, and a coloring pigment or the like may be contained in order to obtain an original fiber.

  The intrinsic viscosity [η] of the core component is preferably 0.6 to 1.1. When the intrinsic viscosity [η] is lower than 0.6, the tensile strength tends to decrease. On the other hand, when the intrinsic viscosity is higher than 1.1, the sheath component has a low melting point. The heat shrinkage of the steel increases, and the workability tends to decrease.

  Next, the sheath component is mainly composed of a copolyester having a melting point lower than that of the core component. The melting point of the sheath component is preferably 130 to 200 ° C. When the melting point is lower than 130 ° C., the application to be used is limited, and when the melting point is higher than 200 ° C., the heating temperature at the time of fusion bonding is increased, which is not only disadvantageous in terms of cost but also melted. When the bonding temperature is high, the core component is damaged by heat and the tensile strength is lowered.

  And in this invention, it is preferable to make melting | fusing point difference with polyester of a core component into about 50-100 degreeC.

  As the copolyester of the sheath component, those obtained by reacting one or more dibasic acids or derivatives thereof with one or more glycols are preferred.

  Examples of dibasic acids or derivatives thereof include terephthalic acid, isophthalic acid, phthalic acid, P-oxybenzoic acid, 5-sodium sulfoisophthalic acid, naphthalenedicarboxylic acid and other aromatic dibasic acids, oxalic acid, adipic acid, Examples include aliphatic dibasic acids such as sebacic acid, azelaic acid, dodecanedicarboxylic acid, aliphatic dibasic acids such as 1,2-cyclobutanedicarboxylic acid, and aliphatic lactone components.

  On the other hand, examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentanediol, P-xylene glycol and the like, polyethylene glycol, polytetramethylene glycol and the like. Examples include alkylene glycols.

  Polymers composed of one or more of these dibasic acids or their derivatives and one or more of glycols are thermally stable and are supplied at a relatively low cost. This is industrially advantageous.

  Among them, especially the copolyester composed of a terephthalic acid component, an aliphatic lactone component, an ethylene glycol component and a 1,4-butanediol component has a relatively high crystallization speed, and is a cooling surface during spinning or after heat bonding processing. Is also preferable. The aliphatic lactone component is preferably a lactone having 4 to 11 carbon atoms, and particularly preferred lactone is ε-caprolactone (ε-CL).

  Moreover, it is preferable that intrinsic viscosity [(eta)] of a sheath component is 0.6-0.8. If the intrinsic viscosity [η] is lower than 0.6, complex forms of spots are likely to occur, and if it is higher than 0.8, the melt flowability at the time of thermal bonding processing deteriorates, and adhesion spots are likely to occur. It is not preferable. Moreover, you may add various additives etc. to a sheath component to such an extent that original performance is not impaired.

  Next, the core-sheath mass ratio (core: sheath) of the heat-bondable long fiber of the present invention is 4: 1 to 7: 1, and preferably 4: 1 to 6: 1. In the heat-bondable continuous fiber of the present invention, the molded product after heat-bonding has excellent rigidity by increasing the mass ratio of PET as a core component.

  When the ratio of the core component is smaller than the core-sheath mass ratio (core: sheath) 4: 1, the rigidity of the molded product after the heat bonding process is deteriorated. On the other hand, when the ratio of the core component is larger than the core-sheath mass ratio (core: sheath) 7: 1, the ratio of the sheath component that becomes the adhesive component decreases, so that the adhesive force is reduced and complex forms are likely to occur. Become.

  And the tensile strength of the heat bondable long fiber of this invention is 3.5 cN / dtex or more, Preferably it is 4.0 cN / dtex or more. Among these, considering the stretchability, it is more preferably 4.0 to 6.0 cN / dtex. If the tensile strength is lower than 3.5 cN / dtex, it may be difficult to use it for industrial material use, which is not preferable because the use is limited.

  The elongation percentage of the heat-bondable long fiber of the present invention is 30% or less, preferably 25% or less. Among these, considering the stretchability, the content is preferably 15 to 25%. When the elongation rate is higher than 30%, a molded product such as a mesh sheet or a net is elongated due to an impact or a tension during construction.

  In addition, the heat-bondable continuous fiber of the present invention may be a multifilament or a monofilament, but it has flexibility when obtaining a molded product and is excellent in workability. preferable. And it is preferable to set it as the multifilament of total fineness 200-2000dtex and single yarn fineness 5-20dtex.

Next, the manufacturing method of the heat-bondable long fiber of the present invention will be described using an example.
It can be manufactured by melt spinning and drawing with a conventional melt compound spinning device, but once wound with undrawn yarn, the copolyester, which is a sheath component, has a low melting point. Since it tends to occur, a spin draw method in which the film is continuously stretched without being wound once and wound after promoting orientational crystallization is preferable, which is advantageous in terms of cost. The winding speed in the spin draw method is preferably about 2000 to 4000 m / min. If the winding speed is slower than 2000 m / min, the productivity is inferior, and if it is faster than 4000 m / min, the spinning property and tensile strength tend to be inferior. .

  And when producing molded articles such as mesh sheets, nets, molding rods, etc. using the heat-bondable long fibers of the present invention, use only the heat-bondable long fibers of the present invention without processing, or The target fineness can be used after being subjected to post-processing such as combined yarn or twist. Moreover, you may mix and use with another fiber, and can also be used for the whole product (molded article) or a part.

Next, the present invention will be specifically described with reference to examples. In addition, the measurement and evaluation of each physical property value in the examples were performed as follows.
(A) Intrinsic Viscosity of Polyester Measured at a concentration of 0.5 g / dl and a temperature of 20 ° C. using a mixture of equal mass of phenol and ethane tetrachloride as a solvent.
(B) Tensile strength and elongation rate Measured according to JIS L-1013, using an autograph DSS-500 manufactured by Shimadzu Corporation at a grip interval of 25 cm and a tensile speed of 30 cm / min.
(C) Melting point It measured using the differential scanning calorimeter DSC-7 type | mold by Perkin Elmer, Inc., and the temperature increase rate was 20 degree-C / min.
(D) Rigidity The obtained fiber is subjected to 120 T / m S twist to form a twisted yarn, which is used as a warp and a weft to produce a plain weave mesh sheet having a woven density of 20.5 × 19.5 / 2.54 cm. Weave anti. This original fabric was subjected to a heat bonding treatment for 3 minutes in a dry heat oven at a temperature of 170 ° C. to obtain a mesh sheet. The resulting mesh sheet was evaluated for the following three grades based on the tactile sensation.
○ ・ ・ ・ Excellent rigidity.
Δ: Slightly rigid.
X: Inferior in rigidity.

Example 1
Using PET (melting point: 255 ° C.) with intrinsic viscosity [η] of 0.70 as the core component, and as the sheath component, the molar ratio of the terephthalic acid component and the ethylene glycol component obtained by the esterification reaction of terephthalic acid and ethylene glycol Obtained by copolymerizing ε-caprolactone in a ratio of 15 mol% with respect to the acid component and 1,4-butanediol at a ratio of 50 mol% with respect to the diol component. A copolyester having a viscosity [η] of 0.70 and a melting point of 160 ° C. was used.
Then, using a conventional melt compound spinning apparatus, a core-sheath type melt compound spinneret having a hole diameter of 0.5 mm was mounted, and spinning was performed at a temperature of 280 ° C. and a core-sheath mass ratio (core: sheath) of 4: 1. The spun yarn was passed through a heating cylinder heated to a length of 15 cm and a temperature of 300 ° C., and then cooled at a cooling air temperature of 15 ° C. and a speed of 0.7 m / sec with an annular spraying device having a length of 40 cm.
Next, the oil agent is applied and taken up by one unheated roller, continuously aligned by 1.02 times with two rollers at a temperature of 90 ° C., and then 5.1 times with three rollers at a temperature of 140 ° C. The film was stretched and subjected to relaxation heat treatment with a 4 roller at a temperature of 120 ° C. at a relaxation rate of 3%. Long fibers were obtained.

Example 2, Comparative Examples 1-2
The same procedure as in Example 1 was performed except that the core-sheath mass ratio (core: sheath) was changed as shown in Table 1.

  Table 1 shows the evaluation results of the tensile strength, elongation, and rigidity of the heat-bondable long fibers obtained in Examples 1-2 and Comparative Examples 1-2.

  As is clear from Table 1, the heat-adhesive long fibers of Examples 1 and 2 were satisfactory in tensile strength and elongation, and were excellent in rigidity. On the other hand, the heat-adhesive long fibers of Comparative Examples 1 and 2 were inferior in rigidity because the mass ratio of the core component was small.

Claims (2)

A core-sheath type composite fiber composed of a core component mainly composed of polyethylene terephthalate and a sheath component mainly composed of a copolyester having a lower melting point than the core component, and a core-sheath mass ratio (core: sheath) Is a thermal adhesive long fiber characterized by having a tensile strength of 3.5 cN / dtex or more and an elongation of 30% or less. The heat-bondable long fiber according to claim 1, wherein the sheath component is a copolyester containing a terephthalic acid component, an ethylene glycol component, a 1,4-butanediol component, and an aliphatic lactone component.