JP2007254908A - Recycled, heat-adhesive fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recycled, heat-adhesive fiber which contains a recycled polyester as a core component, can enough be used as an industrial material or as a domestic material, and has high strength and excellent adhesiveness. <P>SOLUTION: This recycled, heat-adhesive fiber is characterized by comprising a sheath-core type conjugated fiber having a polyester resin containing a recycled polyester as a core component and a copolyester having a lower melting point of 140 to 190°C than that of the core component as a shear component, and having a core-sheath mass ratio of 1:1 to 5:1, a breaking strength of ≥3.0 cN/dtex, and a breaking elongation of 20 to 35%. The copolyester of the sheath component preferably comprises terephthalic acid component, ethylene glycol component, and at least one component selected from 1,4-butanediol component, an aliphatic lactone component and adipic component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a heat-adhesive fiber containing recovered recycled polyester as a core component after use, and can be subjected to processing similar to resin processing for fixing the mesh shape, such as a mesh sheet or a net The present invention relates to a regenerated heat-bondable fiber that can be suitably used for industrial materials and household materials.

  In recent years, environmental pollution due to waste reclamation and incineration has been regarded as a problem, and in particular, PET bottles mainly composed of disposable polyethylene terephthalate (hereinafter referred to as PET) have increased in use year by year and have become a problem. Therefore, it is regarded as important to recycle resources.

  The movement to collect and reuse used PET bottles and PET resin waste generated during the production of PET bottles is increasing year by year, and one of its uses is being reused as a raw material for fibers. Such polyester fibers are attracting attention as environmentally friendly fibers.

  Among these, PET resin scraps derived from PET bottles are suitable for fiberization because they have few impurities and relatively little variation in viscosity.

  For these reasons, the present inventors use, as a core component, a polyester mainly composed of regenerated polyester using PET regenerated from PET resin waste, and a polyester having a melting point of 40 ° C. or more lower than that of the core component as a sheath component. Recycled polyester-based heat-adhesive conjugate fibers (see Patent Document 1) and recycled polyester fibers that are obtained by increasing the intrinsic viscosity of PET recycled from PET resin waste (patents) In particular, the polyester-based heat-adhesive conjugate fiber described in Patent Document 1 is suitable for use in molded articles such as nonwoven fabrics and cushion materials.

  On the other hand, processing using resin such as vinyl chloride has been performed to fix the intersections of mesh sheets and nets used for industrial materials and household materials and to fix the mesh shape. Alternatively, after knitting and weaving using heat-adhesive long fibers as described in Patent Documents 3 to 5, heat treatment is performed at a temperature equal to or higher than the melting point of the sheath component to fix the intersections and the mesh shape. Came to be adopted.

Therefore, the use of recycled polyester for such fibers is also preferable in terms of expansion of recycling and environmental aspects, and can be used for industrial materials and household materials having high strength and excellent adhesiveness using recycled polyester. There is a demand for thermal adhesive fibers.
However, the recycled polyester-based heat-adhesive conjugate fiber described in Patent Document 1 has no explanation about the cutting strength and the cutting elongation, and therefore, this fiber is in a short fiber state as described in the specification. However, it is suitable for use in molded products such as nonwoven fabrics and cushion materials that do not require particularly high cutting strength and elongation, but is not suitable for applications such as mesh sheets and nets that require high strength. It was.
JP 2001-172828 A JP 2002-235243 A JP 2002-194622 A JP 2003-201627 A JP 2004-332152 A

  The present invention solves the above-mentioned problems, has a high strength that can be sufficiently used for industrial materials and household materials, and has excellent adhesiveness, while containing recycled polyester as a core component. Providing adhesive fibers is a technical challenge.

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

That is, the gist of the present invention is as follows.
(1) A core-sheath type composite fiber having a polyester resin containing recycled polyester as a core component and a copolymer polyester having a melting point of 140 to 190 ° C. lower than the core component and a melting point of 140 to 190 ° C. : Regenerated heat-adhesive fiber characterized by having a cutting strength of 3.0 cN / dtex or more and a cutting elongation of 20 to 35%.
(2) The copolymer polyester of the sheath component contains a terephthalic acid component, an ethylene glycol component, and contains at least one component of a 1,4-butanediol component, an aliphatic lactone component, and an adipic acid component. The regenerated heat-adhesive fiber according to (1) above.

  The regenerated heat-adhesive fiber of the present invention can be subjected to the same processing as the resin processing for fixing the intersection part and the mesh shape of a mesh sheet, a net, etc. by heat treatment after weaving and knitting, As the core component contains recycled polyester, it leads to the expansion of recycling. And it has the high intensity | strength which can fully be used and has the outstanding adhesiveness, and can use it suitably for industrial materials and household materials.

Hereinafter, the present invention will be described in detail.
The regenerated heat-adhesive fiber (hereinafter, sometimes referred to as fiber) of the present invention is mainly used for industrial materials and daily life materials, and therefore requires high adhesive strength and strength, and has good spinning properties. Therefore, 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, a polyester resin containing recycled polyester recovered after being used once is used as the core component. Recycled polyester is molded into shapes other than pellets such as PET bottles, films, and fibers for liquid foods and drinks. It is a resin that has been recovered to be molded again without being returned to a low molecular weight. Of these, those obtained by collecting PET bottles are preferred because of their relatively good quality.

  In the fiber of the present invention, such recycled polyester is contained in the polyester resin as the core component, and it is preferable that the recycled polyester is mixed in the polyester resin. And when using the thing derived from a PET bottle as recycled polyester, it is preferable to use the normal polyester resin (virgin polyester) which has PET as a main component as a polyester resin.

  The recycled polyester used for the core component is preferably a recycled polyester obtained by melting PET resin waste derived from a PET bottle with a melt extruder, etc., and regenerated into chips, and generally has an intrinsic viscosity [η] of 0.6 to Although it is about 0.7, it is possible to obtain a fiber having a target strength of 3.0 cN / dtex or more even if a recycled polyester is used alone as a core component by stretching at a high magnification. Further, if necessary, the intrinsic viscosity can be increased by solid phase polymerization or the like.

  Considering these points, the ratio of the recycled polyester in the core component is preferably 50 to 100% by mass, particularly preferably 60 to 90% by mass, and less than 40% by mass is not preferable from the viewpoint of utilization of the recycled polyester.

  Further, the core component may be added with a color pigment, a weathering agent, a heat-resistant agent, etc. as a third component to such an extent that the original performance is not impaired.

  Next, the sheath component of the fiber of the present invention is preferably a copolyester that is difficult to peel off from the core component even by friction or bending and is compatible with the core component. Such a copolymer is a dibasic acid. Alternatively, it can be obtained by reacting one or more of its derivatives with one or more of glycols.

  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, etc., polyethylene glycol, polytetramethylene glycol, etc. Examples include polyalkylene glycols.

  Polymers consisting 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, a copolyester containing at least one component among a 1,4-butanediol component, an aliphatic lactone component and an adipic acid component, a terephthalic acid component and an ethylene glycol component is preferable. In particular, a copolyester comprising a terephthalic acid component, an aliphatic lactone component, an ethylene glycol component, and a 1,4-butanediol component has a relatively high crystallization speed, which is preferable from the viewpoint of cooling during spinning or after heat bonding. . The aliphatic lactone component is preferably a lactone having 4 to 11 carbon atoms, and particularly preferred lactone is ε-caprolactone (ε-CL).

  The sheath component has a lower melting point than that of the core component, and the melting point is required to be 140 to 190 ° C., among which 150 to 180 ° C. is preferable. When the melting point of the sheath component is lower than 140 ° C., the use is limited, and when the melting point is higher than 190 ° C., the heating temperature at the time of the melt bonding process becomes high, which is disadvantageous in terms of cost. However, when the melt bonding temperature is increased, the core component causes a decrease in strength.

  And in this invention, it is preferable to make melting | fusing point difference with polyester of a core component into about 50-100 degreeC. Moreover, various additives, such as a matting agent, a coloring pigment, an antibacterial agent, and a heat-resistant agent, may be added to the sheath component as necessary to the extent that the original performance is not impaired.

  The intrinsic viscosity [η] of the sheath component is preferably 0.6 to 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, melt flowability at the time of thermal bonding processing is deteriorated and adhesion spots are likely to occur. This is not preferable.

  The fiber of the present invention has a core-sheath mass ratio of 1: 1 to 5: 1, preferably 2: 1 to 4: 1. When the core component is smaller than this range, it is difficult to obtain high strength, and when the core component is larger, it is not preferable because a decrease in adhesive force and complex form spots are easily generated.

  Next, the cutting strength of the fiber of the present invention needs to be 3.0 cN / dtex or more, and preferably 3.5 cN / dtex or more. If the cutting strength is lower than 3.0 cN / dtex, the application is limited, which is not preferable. In consideration of the intrinsic viscosity of the core component and the fiber cutting elongation of 20 to 35% as described later, the cutting strength is preferably 3.5 to 4.5 cN / dtex.

  Moreover, the cut elongation of the fiber of the present invention needs to be 20 to 35%, and preferably 20 to 30%. If the cut elongation is lower than 20%, recycled polyester generally contains more foreign matter than virgin polyester, so that problems such as single yarn breakage (fluff) are likely to occur during production (particularly stretching), and 35% If it is higher, a mesh sheet, a net or the like obtained by knitting or weaving this fiber tends to stretch due to tension or impact during construction or use, such being undesirable.

  The form of the fiber of the present invention may be either a long fiber or a short fiber, but a long fiber is preferable for industrial materials such as mesh sheets and nets and household materials, and short for non-woven fabrics and cushions. Fiber is preferred.

  In the case of long fibers, the yarn fineness is preferably from 200 to 2000 dtex, and the single yarn fineness is preferably from 5 to 15 dtex, which is good in yarn production. In the case of short fibers, the single yarn fineness is preferably 3 to 30 dtex, and the fiber length is preferably 5 to 50 mm.

  And when weaving and weaving mesh sheets, nets, etc. using the fibers (long fibers) of the present invention, the fibers of the present invention may be used as they are. You may mix and use with fiber. Further, when weaving and knitting, a fabric may be formed using only the fibers of the present invention, but it may be used as a part of the structure depending on the purpose and purpose.

  The mesh sheet or net fabric obtained by weaving and knitting as described above is subjected to heat treatment, for example, with a heating roller bonding apparatus, to melt or soften the copolymer polyester, which is a low melting point component of the sheath component, A mesh sheet with a fixed intersection and a net with a fixed mesh shape are obtained.

  Next, as a method for producing the regenerated heat-adhesive fiber of the present invention, for example, in the case of long fiber, it can be produced by a conventional melt compound spinning apparatus. It is preferable to carry out by a spin draw method in which stretching is performed continuously without taking. The winding speed is preferably about 2000 to 4000 m / min. If it is slower than 2000 m / min, the productivity is inferior. If it is faster than 4000 m / min, problems such as single yarn breakage (fluff) are likely to occur during stretching. The cutting strength of the resulting fibers tends to be inferior.

Next, the present invention will be specifically described with reference to examples. In addition, each physical-property value in an Example was measured with the following method.
(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) Cutting strength and cutting elongation Using an autograph DSS-500 manufactured by Shimadzu Corporation according to JISL-1013, measurement was performed at a grip interval of 25 cm and a pulling 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) Stretchability Each 7 kg of rolled cheese was collected, and the fluff on both end faces was visually observed and evaluated in the following two stages.
○… The number of fluff is 2 or less ×… The number of fluff is 3 or more

Example 1
As a core component, only a recycled polyester having an intrinsic viscosity [η] 0.66 (melting point 255 ° C.) obtained by melting flaky PET resin waste derived from a PET bottle and forming a chip is used, and terephthalic acid is used as a sheath component. A PET oligomer having a terephthalic acid component and an ethylene glycol component obtained by the esterification reaction of ethylene glycol with 1: 1.13 is a PET oligomer having 15 mol% of ε-caprolactone with respect to the acid component and 1, A copolyester having an intrinsic viscosity [η] of 0.70 and a melting point of 160 ° C. obtained by copolymerizing 4-butanediol at a ratio of 50 mol% with respect to the diol component was used.
Then, using a conventional melt composite spinning apparatus, a core-sheath type melt composite 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 of 3: 1. The spun yarn was passed through a heating cylinder heated to a length of 30 cm and a temperature of 200 ° C., and then cooled at a cooling air temperature of 15 ° C. and a speed of 0.7 m / sec by a horizontal spray device having a length of 150 cm.
Next, an oil agent is applied and taken up by a non-heated first roller, continuously aligned by 1.02 times with a second roller having a temperature of 100 ° C., and thereafter, with a third roller having a temperature of 140 ° C. Double stretching, 3% relaxation treatment with 4th roller at 120 ° C, winding 1% relaxation and winding in a winder of 2500m / min. Concentric circular cross section of 555dtex / 48 filament Regenerated heat-adhesive fibers (long fibers) were obtained.

Example 2
As the core component, except for using the polyester obtained by dry blending the recycled polyester used in Example 1 and PET having an intrinsic viscosity [η] of 0.75 (melting point 256 ° C.) at a mass ratio of 1: 1, Example 1 was performed.

Comparative Example 1
The same procedure as in Example 1 was performed except that the core-sheath mass ratio was changed to 1: 2.

Comparative Example 2
It carried out similarly to Example 1 except having changed the draw ratio into 5.4 times.

  Table 1 shows the evaluation results of the cutting strength, cutting elongation and stretchability of the fibers obtained in Examples 1-2 and Comparative Examples 1-2.

  As is clear from Table 1, the fibers obtained in Examples 1 and 2 have a high cutting strength of 3.0 cN / dtex or higher, an appropriate cut elongation of 20 to 35%, and stretchability. It was also excellent.

On the other hand, the fiber obtained in Comparative Example 1 was inferior in cutting strength because the ratio of the core component was small, and the fiber obtained in Comparative Example 2 was inferior in stretchability because the cut elongation was low. .

Claims (2)

  A core-sheath type composite fiber having a polyester resin containing recycled polyester as a core component, and a copolymer polyester having a lower melting point and a melting point of 140-190 ° C. than the core component as a sheath component, the core-sheath mass ratio is 1: 1-1 A regenerated heat-adhesive fiber having 5: 1, a cutting strength of 3.0 cN / dtex or more, and a cutting elongation of 20 to 35%. The copolyester of the sheath component is a copolyester containing a terephthalic acid component, an ethylene glycol component, and at least one component of a 1,4-butanediol component, an aliphatic lactone component, and an adipic acid component. Item 2. Recycled heat-bondable fiber according to item 1.