JPS6347806B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a polyester heat-adhesive fiber, and its purpose is to have excellent heat-adhesive properties even at low temperatures, and to provide fibers and fiber aggregates using the fibers. It is an object of the present invention to provide fibers made of polyhexamethylene terephthalate-based or polyhexamethylene-butylene terephthalate-based copolyester, which can be manufactured smoothly without any process troubles. (Prior Art) Heat-adhesive fibers for producing nonwoven fabrics and the like by interfiber heat fusion are known. For example, there are composite fibers with polypropylene and polyethylene as an adhesive component, or composite fibers with polyethylene terephthalate and polyethylene terephthalate with an ethylene-vinyl alcohol copolymer as an adhesive component. In recent years, the role of polyester fibers such as polyethylene terephthalate (hereinafter abbreviated as PET) has grown in the textile field, especially in the nonwoven fabric field. With the increasing demand for manufacturing polyester, adhesive fibers for polyester are strongly desired. The above-mentioned known adhesive fibers have good thermal adhesion properties between adhesive polymers, but when used in combination with other main fibers for nonwoven fabrics, etc., the types of main fibers that can be bonded are very limited, and polyester I have not found anything that can be adhered to. for example,
Although polyethylene is self-adhesive, it hardly adheres to common commercially available fibers that have different chemical structures.
Furthermore, copolymerized nylon adheres to nylon fibers, but does not adhere to polyester fibers made of the same condensation polymer. Additionally, ethylene-vinyl alcohol copolymers exhibit adhesion to rayon, vinylon, or nylon, which have relatively similar solubility parameters, but they also do not adhere to polyester. In addition, when polyethylene, copolymerized nylon, etc. are used as adhesive polymers, they have poor compatibility with polyester, so the adhesive polymer may peel off during the process, resulting in frequent problems such as the generation of white powder. The problem of reduced product yield was unavoidable. From the above, in order to bond polyester fibers, it is common sense to use a polyester polymer as an adhesive component due to the similarity in chemical structure and solubility parameters, as it is good for the adhesive strength of nonwoven fabrics and processability. It's possible to think about it. In fact, many soft, amorphous copolymer polyesters with low glass transition points have been proposed as solvent-soluble or hot-melt adhesives that use polyester as an adhesion partner. However, when softening amorphous copolymer polyester with a low glass transition point is used as an adhesive fiber, it passes through specific equipment and a specific thermal history in the fiber or nonwoven manufacturing process. During the temperature treatment process, the amorphous copolyester softens and fuses, making it impossible to form into fibers, making it impossible to use ordinary copolyesters for adhesives at all. To give a more specific example, when a copolymerized polyester is taken out of a polymerization tank and cut into pellets, the polymer is too soft and difficult to cut using an ordinary amorphous copolyester with a low glass transition point. Also, the pellets stick together during the drying process before spinning. Also, when the molten polymer is extruded from a spinneret to form fibers and the fiber bundles are placed in a can or wound on a bobbin, there is severe adhesion between single fibers or fiber bundles, and if the polymer somehow manages to pass the pelletizing and drying steps. Alternatively, even if the fibers are directly extruded from a polymerization vessel and the pelletizing and drying steps are omitted, it is difficult to obtain spun fibers. Furthermore, when stretching, crimping, cutting, etc.
Furthermore, adhesion and fusion between single fibers occur, making it impossible to obtain good fibers. In addition, even if fiberization is performed incompletely, for example, when turning into a non-woven fabric, problems such as the occurrence of neps may result in poor card passage, or problems with adhesion occur during adhesive processing, making it impossible to make a non-woven fabric. . The processing properties required for this spinning and the subsequent fiberization and nonwoven fabric manufacturing processes are extremely strict, and even if the spinning process passes through the pelletizing and drying processes without any trouble, there are very few products that can be fabricated into fibers or nonwoven fabrics. The patent discloses fibers containing copolymerized polyester as an adhesive component. However, when producing fibers from the patented copolyester polyester, there are problems such as those mentioned above, and in reality, it is almost impossible to make fibers, or even if it is possible to produce fibers in a short time or in small quantities, it takes a long time to produce fibers. It is difficult to continue stable production. In commercial production and operational production, stable production over long periods of time is an absolute requirement, and it must be said that the adhesive fiber described in the patent is still insufficient. On the other hand, fiber-forming polyesters with a small amount of copolymerization and a lower degree of modification, that is, polymers that maintain a high level of crystallinity and have a fast crystallization rate, are used in the fiber or nonwoven fabric manufacturing process. However, the adhesion of polyester to PET or polybutylene terephthalate (PBT), which are currently mass-produced commercially, is generally low, and it cannot be used as an adhesive fiber. If the amount of copolymerization is small with PET-based or PBT-based copolyester, each
Adhesion to PET or PBT may be good to some extent. However, in such cases, the high melting point of the copolymerized polyester makes it impossible to bond at low temperatures, requiring high temperatures for bonding, making conventional equipment unusable, or even if high-temperature processing equipment is used, it requires energy. This is not preferable because it causes a lot of loss and the molded product is deformed and its texture deteriorates. (Problems to be Solved by the Invention) The present inventors have discovered that the present invention has excellent adhesion to polyester;
In particular, as a result of various research into fibers that can be bonded at low temperatures and whose processing efficiency for manufacturing fibers and non-woven fabrics is at a level that can be commercially produced, we have found that copolymer polyesters that can be used for textiles are completely different from those for so-called adhesives. is suitable, and the above-mentioned method can be achieved for the first time by using a fiber made of a polyhexamethylene terephthalate-based or polyhexamethylene-butylene terephthalate-based copolyester having a copolymer composition and physical properties within a specific limited range as described in the claims. It has been found that the problem can be completely solved and high-quality adhesive fibers that can be processed for low-temperature adhesive treatment can be obtained. (Means for Solving the Problems) It is known that copolyesters similar to the composition of the present invention can be used as so-called adhesives. However, it is completely unknown that fibers or nonwoven fabrics can be smoothly produced from copolyester having the composition of the present invention and polymers having specific physical properties without any process troubles. Furthermore, the physical properties of polyester adhesive fibers that enable them to be made into fibers or non-woven fabrics were revealed for the first time in the present invention. That is, the adhesive polymer for polyester adhesive fibers is a copolymerized polyester, and the most important point is to impart a specific degree of crystallinity and a specific crystallization rate, and the polymer composition has a low melting point. We have come to the conclusion that this is a necessary condition. The copolymer composition and physical properties suitable for adhesive fibers are completely different from those of so-called adhesives. That is, adhesives that generally have lower crystallinity, and are particularly amorphous, are often used. Furthermore, adhesives that have a high peel strength when bonded in film form are used, but the present inventors have studied adhesive fibers from a completely different perspective than adhesives, and have developed adhesive fibers that have completely different compositions than adhesives. It was discovered that copolymerized polyester has good physical properties. In other words, while maintaining the ability to adhere to polyester fibers at low temperatures,
In order to maintain processability for fiberization,
The most important point is how to maintain the crystallinity and crystallization rate of the polymer above a predetermined level, and this is the first time that we have discovered what the polymer composition is for this purpose. To specifically explain the present invention, the amount of 1,6-hexanediol (HD) copolymerized in the polyhexamethylene terephthalate-based or polyhexamethylene-butylene terephthalate-based copolyester of the present invention is as follows: 20 mol% or more (hereinafter, the amount of copolymerization refers to the total amount defined above) based on the total acid component (if oxyacid is included, one-half is considered to be the acid component and one-half is considered to be the diol component). (expressed in mol % based on the acid component), preferably 25 mol % or more, more preferably 30 mol % or more. The present invention is based on the discovery that by using HD as a component of a copolymerized polyester, it exhibits good adhesion even in low-temperature processing, and the processability of forming into fibers and nonwoven fabrics is good. In this case, the object of the present invention cannot be achieved. It has been found that maintaining the crystallization rate is an absolute requirement for fiberization, and for this purpose, a 1,6-hexanediol component with a fast crystallization rate is essential. In addition, 1,4 in the copolymerized polyester of the present invention
-Butanediol (BD) copolymerization amount is 80 mol%
Hereinafter, the amount used is preferably 75 mol% or less, more preferably 70 mol% or less. If it exceeds 80 mol%, it becomes difficult to achieve both low-temperature adhesion and processability, which is not preferable. The BD component also does not significantly reduce the crystallization rate and is an effective component for forming fibers, but when the BD component is rich, the melting point of the polymer increases, making it difficult for binder fibers with low-temperature adhesion, which is the original purpose, to be used. You won't be able to get it. The copolymer component A of the present invention is adipic acid or sebacic acid. In these two cases, the crystallization behavior, that is, the crystallinity to some extent is maintained, the crystallization rate is not reduced too much, the hardness is appropriate, and both adhesion and processability can be achieved. Unsaturated dicarboxylic acids cause unstable polymerization,
Moreover, it is not preferable because the fiber becomes brittle. Branched dicarboxylic acids are undesirable because they greatly reduce crystallinity. Isophthalic acid is used as the copolymer component B of the present invention. The copolymerization component C of the present invention is ethylene glycol, diethylene glycol, triethylene glycol or cyclohexanedimethanol.
Although these reduce the melting point or hardness, they are selected so that the decrease in crystallinity is as small as possible. The total amount of component A and component C used in the present invention is 3 to 35 mol%, preferably 5 to 32 mol%, and more preferably 7 to 29 mol%. If it is less than 3 mol%, the adhesion will be insufficient, and even if some degree of adhesion is achieved, the texture of the fibers and nonwoven fabric will not be good. On the other hand, if it exceeds 35 mol%, it is undesirable because the crystallization behavior deteriorates, that is, the crystallization rate decreases and the crystallinity decreases significantly, resulting in poor fiber forming properties, softening of the polymer, and decreasing processability. . Further, the copolymerization amount of component C of the present invention is 20 mol% or less, preferably 16 mol% or less, more preferably
Up to 12 mol% is used. If it exceeds 20 mol%, the above-mentioned crystallization behavior will deteriorate, resulting in poor processability, which is not preferable. The total of component B and component C of the present invention is 30 mol% or less, preferably 26 mol% or less, more preferably
Up to 22 mol% is used. If it exceeds 30 mol%, crystallization behavior etc. deteriorate and processability becomes poor, which is not preferable. Furthermore, the total amount of component A, component B, and component C of the present invention is 3 to 40 mol%, preferably 5 to 36 mol%, and more preferably 7 to 32 mol%. If it is less than 3 mol%, adhesion may be insufficient, and even if some adhesion occurs, the texture of the fibers and nonwoven fabrics may not be good, or the melting point of the copolyester may be high, making low-temperature adhesion impossible. . On the other hand, if it exceeds 40 mol%, it is not preferable because it causes deterioration of crystallization behavior, softening of the polymer, etc., and reduces processability. The copolymerized polyester used in the fiber of the present invention must satisfy all of the above compositional conditions, and must also ensure stability in the fiber and nonwoven fabric manufacturing process at a commercial production level and quality as an adhesive fiber. For this purpose, the degree of crystallinity, crystallization rate and adhesive strength must be appropriate. In other words, an adhesive polymer as a binder fiber that maintains the crystallinity and crystallization speed of the polymer to maintain the processability of fiberization, sufficient strength as a nonwoven fabric, and good texture must be considered economically. It has been found that the folic acid component is essentially terephthalic acid, and the glycol component is essentially a component based on 1,6-hexanediol or 1,4-butanediol. Specifically, the copolymerized polyester of the present invention has a heat of crystal fusion (△Hu) of 2.0 cal/g or more, preferably 2.5 cal/g or more, and more preferably 3.0 cal/g.
The above are used. If it is less than 2.0 cal/g, it is not preferable because it tends to cause sticking during fiber production. △Hu
The measurement is carried out by extracting fine fibers or thin film pieces from the molten polymer, cooling them, leaving them at room temperature for three days or more, and then applying the sample to a differential scanning calorimeter (DSC) in nitrogen at a rate of 10°C/min. death,
It is determined from the area of the endothermic peak during melting. In addition, the copolymerized polyester of the present invention has a minimum crystallization time (Minimum Crystalization Time).
CTmim.) within 2.5 minutes, preferably within 2 minutes,
More preferably, a time within 1.5 minutes is used.
If the time is longer than 2.5 minutes, sticking may occur during fiber production, which is not preferable. CTmim. is a process of crystallization in the temperature range of 0 to 100℃, where a small piece of substantially non-oriented film is rapidly cooled from a molten state to a set temperature, and the time when it starts to whiten when left at that temperature is defined as the crystallization start time. This is the crystallization start time at the temperature where the start time is the shortest.
To find CTmim., it is not necessarily necessary to change the temperature and measure CTmim.
A sufficient condition is that the crystallization time at a certain temperature in the range of 100°C is within 2.5 minutes. Depending on the type of copolymerized polyester, the temperature at which CTmim. is indicated may be close to 0°C, or may be close to 100°C.
The crystallization time in the actual fiber manufacturing process varies depending on the temperature history, etc., but it is natural that the crystallization speed will be faster if the temperature is set to indicate CTmim. In addition, when the fibers are highly oriented as during spinning, the crystallization rate may increase, but as defined in the present invention,
CTmim. can be used as a measure related to process performance. Furthermore, the polyester of the present invention has a shear strength (SS) of the PET film bonded to it.
The weight of the material used is 6 Kg/cm ² or more, preferably 7 Kg/cm ² or more, more preferably 8 Kg/cm ² or more.
If it is less than 6 kg/cm ² , the adhesive strength in fibrous form, especially the strength of nonwoven fabric, will be insufficient, which is not preferable. The SS of the present invention is a copolymerized polyester film with a thickness of 0.3 mm and a biaxially stretched PET film manufactured by Mitsubishi Plastics (trade name, Diamond Foil, thickness 0.1 mm) at a temperature of 20 mm.
℃, relative humidity of 65% in a room, heated to a temperature 20℃ higher than the melting point of the copolymerized polyester, and then heated to a pressure of 5℃.
After gluing at Kg/cm ² , leave it for 24 hours, and then
This is a value measured at 20cm/min. The copolymerized polyester of the present invention may contain small amounts of additives, such as matting agents such as titanium oxide, antioxidants, fluorescent brighteners, stabilizers, or ultraviolet absorbers. The copolymerized polyester fibers of the present invention and the fiber aggregates and nonwoven fabrics made from the fibers are preferably manufactured using unique machines and equipment most suitable for the production, but the machines and equipment that have been used in the past are not changed much. It can be manufactured without Further, the present invention has great significance in that the fibers are specified so that conventional machines and devices can be used. The fiber of the present invention can be used as a single fiber (homofilament) spun alone, but it is preferable to spin it together with other melt-spun polymers and use it as a composite fiber because the shape stability of the nonwoven fabric and the strength of the nonwoven fabric are excellent. Therefore, it is used as a composite fiber. As other composite spinning components, thermoplastic polymers having a melting point of 150° C. or higher are used. For example,
PET, PBT, nylon-6, nylon-6,6,
There are polypropylene, etc. When used as an adhesive fiber, the ratio of the copolymerized polyester component to the total circumference of the cross section of the composite fiber, that is, the cross-sectional circumference of the fiber, is preferably 40% or more. Although the fibers of the present invention can be used as modified fibers other than adhesive fibers, they are very suitable for use as adhesive fibers that are subjected to fusing treatment at temperatures above the softening point of the fibers. The fibers of the present invention can be used as a fusion-treated fiber aggregate consisting only of composite fibers of copolyester polyester and other polymers, but can also be used as a fusion-treated fiber aggregate consisting of 10% by weight or more of other fibers. used. As a fiber aggregate, it is particularly suitable for nonwoven fabrics,
A nonwoven fabric with high strength can be obtained. Among them, PET or PET-like fibers are used as mixed fibers.
In the case of polyester containing TA as a component, the adhesion not only between adhesive fibers but also with the TA-based polyester is good, and a nonwoven fabric with high strength can be obtained. The significance of the present invention is great in that it has made it possible to produce a good polyester nonwoven fabric without conventional fibers adhering to TA polyester. Next, the present invention will be explained by examples. Examples are summarized in Table 1. In the examples, the mole indicating the copolymer composition amount indicates the mol% based on the total acid component of the polyester produced. [η] is the intrinsic viscosity (dl/g) of polyester measured at 30°C in a mixed solvent of equal weights of phenol and tetrachloroethane. The melting point (mp) of polyester is determined by measuring the point at which the polarized light of the sample on the hot plate disappears or the pouring point using a micro-melting point measuring device. In addition, the strength of the nonwoven fabric is determined by 20 parts by weight of adhesive fiber and PET.
After blending with 80 parts by weight of fiber (3D x 51mm), carding and web formation, 10Kg/
It is expressed as the breaking length (Km) of the nonwoven fabric obtained by thermally bonding the adhesive fibers by melting the adhesive fibers at cm ² for 1 minute. Example 1 Polycondensation reaction was carried out at 260℃, 75 mol of TA,
A copolymerized polyester consisting of 100 moles of HD and 25 moles of sebacic acid was produced, extruded into water in the form of strands from the bottom of the polymerization vessel, cut using a strand cutter, and pelletized. The extrusion and cutting conditions were good, and pellets with a good shape were obtained. The obtained copolymerized polyester has a diameter of [η] 1.24m.
p.118-122°C, △Hu5.8cal/g, crystallization time at room temperature was 13 seconds, and SS was 15.8Kg/ ^cm2 . When this pellet was dried at 70°C in a vacuum dryer, no agglutination was observed. This copolyester is used as a sheath with [η]0.67.
Core-sheath composite spinning was performed using PET as a core at a core/sheath weight ratio of 40/60. It was extruded at a spinning head temperature of 287°C and wound at 1000 m/min. The wound fibers could be stably spun for a long period of time without any sticking between single fibers or fiber bundles. This spun yarn was stretched 3.5 times in a water bath at 78°C,
Subsequently, it was shrunk by 15% at 87℃ in a water bath, further crimped using a stuffing box type crimper, and then cut to give a fineness of 3.1 dr, strength of 3.7 g/d, and elongation of 52.
% of fiber could be obtained without any particular trouble. 20 parts by weight of this composite fiber and 80 parts by weight of PET fiber were mixed to obtain a high-strength nonwoven fabric with a breaking length of 3.3 km.
Note that no particular trouble was observed during the nonwoven process. Example 2 Polycondensation reaction was carried out at 260℃, TA80mol, HD50
A copolymerized polyester consisting of 50 moles of BD, 15 moles of adipic acid, and 5 moles of isophthalic acid was produced, extruded into water in the form of strands from the bottom of the polymerization vessel, and cut into pellets using a strand cutter. The extrusion and cutting conditions were good, and pellets with a good shape were obtained. The obtained copolymerized polyester had [η] 1.18, mp123-127℃, △
Hu3.6cal/g, crystallization time at room temperature is 45 seconds, SS
was 14.2Kg/ ^cm2 . When this pellet was dried at 70°C in a vacuum dryer, no agglutination was observed. This copolyester is used as a sheath with [η]0.67.
Core-sheath composite spinning is performed using PET as the core in the same manner as in Example 1, and then stretching, shrinking, crimping, and cutting are performed to obtain fibers with a fineness of 3.1 dr, strength of 3.5 g/d, and elongation of 50% without any particular trouble. I was able to do that. A high-strength nonwoven fabric with a breaking length of 3.2 km was successfully obtained from this composite fiber and PET fiber. Example 3 A copolymerized polyester having the copolymer composition and physical properties shown in Table 1 is used as a sheath, and nylon-6 is used as a core, and core/sheath =
Core-sheath composite spinning was performed at a weight ratio of 40/60. It was extruded at a spinning head temperature of 270°C, spun at 1000 m/min, and then stretched, shrunk, crimped, and cut.
A fiber with a fineness of 3.5 dr, a strength of 4.7 g/d, and an elongation of 53% was obtained. Processability was benign and there were no particular troubles, and no adhesion between fibers was observed. A high-strength nonwoven fabric with a breaking length of 4.2 km was successfully obtained from this composite fiber and PET fiber. Examples 4 to 6 Core-sheath composite spinning was performed in the same manner as in Example 1 using a copolymerized polyester having the copolymer composition and physical properties shown in Table 1 as a sheath and PET as a core, and then in the same manner as in Example 1. The fabric was made into fibers and non-woven fabrics, and non-woven fabrics with good strength were obtained in both cases. The process properties of fiberization and nonwoven fabrication were both good, and no particular trouble was observed. Example 7 Polycondensation reaction was carried out at 260℃, 90 mol of TA,
IPA 10 mol, HD 90 mol, ethylene glycol 10
A copolymerized polyester consisting of moles was produced, extruded into water in the form of strands from the bottom of the polymerization vessel, cut using a strand cutter, and pelletized. After cooling the strand in water, it was once run in the air for several seconds to completely crystallize, and then cut with a strand cutter. The cutting condition is very good.
Pellets with good shape were obtained without causing any trouble. The obtained copolymerized polyester had [η] 1.20, m.
p.120-128°C, △Hu5.0cal/g, crystallization time at room temperature was 10 seconds, and SS was 15.0Kg/ ^cm2 . When this pellet was dried at 70°C in a vacuum dryer, no agglutination was observed. Next, use this copolymerized polyester as a sheath [η]
With 0.67 PET as the core, core/sheath = 50/50 weight ratio,
Core-sheath composite spinning was performed. Spinning head temperature 287℃
It was extruded at a speed of 800 m/min and rolled up at a speed of 800 m/min. The wound fibers could be stably spun for a long period of time with almost no sticking between single fibers or fiber bundles. This spun yarn was stretched 3.8 times in a water bath at 65°C,
Next, the fibers were shrunk by 10% at 90°C in a water bath, further crimped using a stuffing box type crimper, and then cut. I was able to get it without any trouble. A nonwoven fabric with a basis weight of 30 g/m ² was created using 100% of this composite fiber. No particular trouble was observed during the non-woven process, and a good non-woven fabric was obtained. After treating the wet cloth with hot air at a temperature of 140°C for 2 minutes, the nonwoven fabric had a tear length of 4.5 kg, which was extremely strong and had a soft texture. Example 8 A polycondensation reaction was carried out at 260°C to produce a copolymerized polyester consisting of 90 moles of TA, 10 moles of adipic acid, 90 moles of HD, and 10 moles of ethylene glycol.
Good pellets were obtained in the same manner as above. The obtained copolymerized polyester had [η] 1.22, m.
p.116-126°C, △Hu5.5cal/g, crystallization time at room temperature was 8 seconds, and SS was 12.0Kg/ ^cm2 . Composite fibers were made from these pellets in the same manner as in Example 2, and using 100% of the composite fibers, the fabric weight was 30g/
A cm ² nonwoven fabric was obtained under similar temperature conditions. rupture length
A high strength non-woven fabric with a length of 4.0 km was obtained. The texture was also soft and good. Note that no particular trouble was observed during the process. Comparative Example 1 A copolymerized polyester consisting of 60 moles of TA, 100 moles of HD, and 40 moles of sebacic acid was obtained by polycondensation reaction. Extrude it into water from the bottom of the polymerization vessel in the form of a strand, cut it using a strand cutter, and
Pellets having the physical properties listed in the table were obtained. A cooling bath was provided in front of the cutter, and even if the strand was cut after passing through the cooling bath, it was quite difficult to insert the strand into the cutter, and the operation of the cutter was often stopped due to the accumulation of uncut strands. The pellets were dried for a long time at 50°C in a vacuum dryer. This copolymerized polyester is used as a sheath, [η]0.67
Using PET as a core, core-sheath composite spinning was performed at a core/sheath weight ratio of 40/60. Spinning head temperature 270℃
Although the spinning speed was changed to 287° C. and spun at 1000 m/min, it was not possible to obtain fibers with extremely good adhesion between single fibers and between fiber bundles. Comparative example 2 TA90 mol, HD60 mol, sebacic acid 10 mol,
A copolyester consisting of 40 moles of ethylene glycol was obtained by polycondensation reaction. It was extruded into water in the form of a strand from the bottom of the polymerization vessel, and after passing through a cooling tank, was cut using a strand cutter to obtain pellets having the physical properties listed in Table 1. The yield of pellets decreased because the operation was often stopped due to poor strand cutting conditions. Core-sheath composite spinning was performed in the same manner as in Comparative Example 2 using this copolymerized polyester as a sheath and PET as a core. Although the spinning head temperature was changed from 270°C to 287°C and spinning was carried out at 1000 m/min, it was not possible to obtain fibers with excellent adhesion between the fibers. Comparative Examples 3 to 9 Core-sheath composite spinning was carried out in the same manner as in Comparative Example 1 using a copolymerized polyester having the copolymer composition and physical properties shown in Table 1 as a sheath and PET as a core, but in all cases, there was no difference between the fibers. A lot of sticking occurred and it was not possible to obtain good fibers. Comparative Example 10 Using the copolymerized polyester shown in Table 1, core-sheath composite spinning, fiberization, and nonwoven fabrication were carried out in the same manner as in Example 2. Although the processability was good with no interfiber adhesion, the tearing length of the nonwoven fabric was 1.2 km. Comparative Example 11 Core-sheath composite spinning was carried out in the same manner as in Example 2 using the copolymerized polyester shown in Table 1 with [η] 0.41 and SS 4.8 Kg/cm ² . Although no interfiber agglutination was observed, thread breakage occasionally occurred. Next, Example 1
Fiberization and non-woven fabric are carried out in the same manner as above, and the tearing length is
0.6Km of non-woven fabric was obtained. Comparative Example 12 The copolymerized polyester listed in Table 1 was polymerized at
Manufactured at 260℃. It took a long time to increase [η] and the polymer was heavily colored. Then, in the same manner as in Comparative Example 2, core-sheath composite spinning, fiberization, and nonwoven fabrication were performed. Although the processability was good with no adhesion between fibers, the tearing length of the nonwoven fabric was 1.7 km. Comparative Example 13 Polymerization temperature of copolyester listed in Table 1
Manufactured at 260℃. It took a long time to increase [η] and the polymer was heavily colored. Next, core-sheath composite spinning was carried out in the same manner as in Comparative Example 2, but a large number of fibers stuck together and it was not possible to obtain good fibers. Comparative Example 14 Polyethylene/polypropylene composite fibers (manufactured by Chitsuso Co., Ltd., 3 dr x 51 mm) were made into a non-woven fabric in the same manner as in Example 1 to obtain a non-woven fabric with a tearing length of 0.4 km. The SS of polyethylene film and PET film was 0.3Kg/cm ² . Comparative example 15 Polypropylene fiber (manufactured by Daiwabo Co., Ltd., 2dr x 51mm)
The material was made into a non-woven fabric in the same manner as in Example 1 using
A nonwoven fabric with a tearing length of 0.5 km was obtained. The SS of polypropylene film and PET film was 0.2Kg/cm ² .

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Claims (1)

[Claims] 1. Terephthalic acid, 1,6-hexanediol,
1,4-butanediol and copolymer component A,
When B and C satisfy the following formula at the same time, the heat of crystal fusion is
Polyhexamethylene terephthalate-based or polyhexamethylene-butylene terephthalate-based copolymer polyester having a composition of 2.0 cal/g or more, minimum crystallization time of 2.5 minutes or less, and a shear strength of 6 kg/cm ² or more when bonded with polyethylene terephthalate film. and a thermoplastic polymer having a melting point of 150° C. or higher, the copolymerized polyester having a fiber cross-sectional circumference of 40% or higher. HD=20~100 (1) BD=0~80 (2) A+C=3~35 (3) C=0~20 (4) B+C=0~30 (5) A+B+C=3~40 (6) However, Formulas (1), (2), (3), (4), (5), and (6) represent the copolymerization mole % based on the total acid components. where: HD = 1,6-hexanediol BD = 1,4-butanediol A = adipic or sebacic acid B = isophthalic acid or phthalic acid C = ethylene glycol, diethylene glycol, triethylene glycol, or cyclohexanedimethanol