JPH026864B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a polyester nonwoven fabric having a high degree of elastic recovery. The present invention relates to a method for producing a polyester nonwoven fabric that is mixed with a low melting point polyester binder fiber and has high extensibility, flexibility, and excellent elastic recovery. (Prior Art) Conventionally, nonwoven fabrics have been manufactured using various methods. The main methods to date include methods such as forming short fibers into a sheet-like web using a carding machine and binding the fibers together with an adhesive (binder) or needle punch, or forming sheets in one step immediately after spinning the polymer. Methods such as the spunbond method have been developed. However, all of the nonwoven fabrics produced by these methods have poor elastic recovery properties and have limited applications. Particularly in the field of padded cotton for sports clothing, there is a demand for nonwoven fabrics that are soft to the touch, highly flexible, and have excellent elastic recovery properties in terms of stretch functionality and fit. Attempts are being made to develop For example, (1) Nonwoven fabrics using false twisted yarn made into short fibers. (2) A nonwoven fabric in which latent crimp filaments are cross-arranged and bonded. (3) A nonwoven fabric using composite short fibers having a high number of crimps, as described in JP-A-59-168159. Various nonwoven fabrics have been proposed. (Problems to be Solved by the Invention) However, each of these has several drawbacks, and it has not yet been possible to obtain a nonwoven fabric that is highly extensible, highly flexible, and has excellent elastic recovery properties. That is, in the case of (1), strong crimping causes poor passability through the carding machine, and it is difficult to obtain a uniform nonwoven fabric with many neps. In addition, (2) is uniformity, elastic recovery,
Although it is better than (1) in terms of directionality, it has drawbacks such as complicated equipment and poor productivity. In the case of (3), elastic recovery is not sufficient in areas with a low number of crimps, and in areas with a high number of crimps, as described above.
Similar to (1), the carding machine has poor permeability and there are many neps, making it impossible to obtain a uniform nonwoven fabric. In addition, these proposals generally have little intertwining of the fibers forming the web, have directional properties of the web, and require lamination of the webs, which may cause delamination. The present inventors have solved such non-uniformity, directionality of elasticity, insufficient elastic recovery, structural defects, productivity defects, etc., and have developed sports clothing that requires functionality and fit. The object of the present invention is to provide a novel nonwoven fabric that is sufficiently flexible and has excellent elastic recovery properties and can be used in the field of cotton padding. (Means for Solving the Problems) As a result of intensive research to develop such a new nonwoven fabric, the inventor of the present invention has developed a new highly elongated nonwoven fabric that eliminates the above-mentioned drawbacks. . 3 to 3 structural units having a metal salt sulfonate group
The nonwoven fabric is composed of two components: copolymerized polyester (A) mainly composed of 6 mol% ethylene terephthalate units and polyethylene terephthalate (B), and the number of crimps before heat treatment is 18/25 mm or less. 45% by weight or more of the total fibers, and after mixing the composite fibers with different polyester fibers and/or low melting point polyester binder fibers to form a web, heat treatment at 130°C or higher is performed to increase the crimp number of the composite fibers. A method for producing a polyester-based highly elongated nonwoven fabric, characterized by producing a nonwoven fabric with 50 pieces/25 mm or more. The main points are as follows. The polyester composite fiber in the present invention is a polyester mainly composed of ethylene terephthalate and copolymerized with a structural unit having a metal sulfonate group.
A composite fiber consisting of two components (A) and polyethylene terephthalate (B) is essential. The reason for this is that, as in the present invention, relatively coarsely crimped raw cotton is carded to form a web, and then heat treated to develop high crimps and to obtain a highly elastic nonwoven fabric, the above-mentioned method is necessary. This is because the high shrinkage of polyester (A) copolymerized as a two-component composite fiber can be utilized. When producing polyethylene terephthalate, such copolymerized polyester (A) is used in the production of polyethylene terephthalate.
3 to 6 mol% of an ester-forming compound having a metal salt sulfonate group such as sodium sulfophthalic acid, 4-sodium sulfophthalic acid, or ester-forming derivatives thereof
It can be obtained by adding and copolymerizing. Further, a small amount of other components may be copolymerized if necessary. The fiber obtained by the present invention is a composite fiber in which copolymerized polyester (A) and polyethylene terephthalate (B) are eccentrically joined, and is a latent crimped fiber that develops a spiral crimp upon relaxation heat treatment. Although the composite form is not particularly limited, a side-by-side type is preferable to a core-sheath type. Also,
A small amount of additives such as matting agents, gloss improvers, antistatic agents, etc. may be added, and the fiber cross-sectional shape is not limited to a circular cross-section, but may also be a triangular cross-section or other irregular cross-section, and of course, a hollow cross-section may also be used. good. The copolymerization ratio of the structural unit having a metal salt sulfonate group in the copolymerized polyester (A) is 3 to 6.
Mol% is appropriate. If it is less than 3 mol %, the ability to develop crimp is insufficient, and if it exceeds 6 mol %, the melting point of the polyester and the strength of the fiber are significantly lowered, making it unsuitable for general use. In order to obtain a nonwoven fabric with a high degree of elastic recovery, the average number of crimps of the fibers constituting the nonwoven fabric must be 50.
pcs/25mm or more. More preferably, the number is 55 pieces/25 mm or more. On the other hand, when forming a web using a carding machine, the average number of crimps of the fibers is 18.
If the number exceeds 25mm, neps etc. will occur and the uniformity of the non-woven fabric will deteriorate. Therefore, when forming a web using a carding machine, the average number of fiber crimps is 18/
less than 25 mm, and after web forming, the web is
A non-woven fabric is formed by heat treatment at a temperature of 0.degree. Such fibers are manufactured by controlling the intrinsic viscosity of the copolymerized polyester (A) and polyethylene terephthalate (B), the copolymerization ratio of the structural unit having a metal sulfonate group in the copolymerized polyester (A), the composite ratio of the two components, the spinning speed, and This can be obtained by appropriately selecting the stretching heat treatment conditions. For example, as a copolymerized polyester (A), 5-
Polyethylene terephthalate copolymerized polyester copolymerized with sodium sulfoisophthalic acid (hereinafter referred to as SIP) is used as the polyester (B), and in the case of a composite fiber with a composite ratio of 1:1, the copolymerized polyester is used.
When the SIP component of (A) is 4 to 6 mol%, the intrinsic viscosity is 0.4
-0.5, the intrinsic viscosity of the polyester (B) is preferably 0.5-0.8, the spinning speed is 1100 m/min or more, and the stretching and tensioning heat treatment temperature is preferably about 145-170°C. In addition, when the SIP component of the copolymerized polyester (A) is 3 to 4 mol%, the intrinsic viscosity of the polyester (A) is 0.45
~0.55, the intrinsic viscosity of polyester (B) is 0.45~0.75
It is preferable that the spinning speed is 1300 m/min or more and the stretching and tensioning heat treatment temperature is about 120 to 145°C. As mentioned above, in order to obtain a nonwoven fabric with high stretchability and excellent elastic recovery, the number of crimps of the composite fibers constituting part or all of the nonwoven fabric should be 50/50.
It is necessary to set it to 25 mm or more, preferably 55 pieces/25 mm or more. The nonwoven fabric of the present invention is not made of 100% polyester fiber in terms of usage and functionality, but can also be blended with natural fibers such as cotton and wool. In addition, from the viewpoint of dimensional stability, etc., a method is often used in which a fibrous binder is mixed and thermally bonded. In such cases, the average number of crimp of the fibers that make up the nonwoven fabric is
The number should be 50 pieces/25 mm or more, preferably 55 pieces/25 mm or more. For example, in order to obtain a preferable high-elasticity nonwoven fabric made by blending 25% polyester fiber with a number of crimps of 17/25 mm, 10% binder fiber, and 65% conjugate fiber of the present invention, the conjugate fiber of the present invention The number of crimps after heat treatment may be set to 70/25 mm or more. (Examples) Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto. The methods for measuring the various physical properties described in the present invention are as follows. Intrinsic viscosity: Measured at 20℃ in a mixed solvent of equal amounts of phenol and tetrachloroethane. Fineness: Measured using JIS L1015 7.5.1A method. Number of crimp: Measured using JIS L1015 7.12.1 method. Nonwoven fabric strength, nonwoven fabric elongation, elastic recovery rate: A sample of nonwoven fabric cut into a width of 25 mm is used. Nonwoven fabric strength and nonwoven fabric elongation were measured using a constant speed extension type tensile tester at a sample length of 100 mm and a tensile speed of 100 mm/min. The elastic recovery rate was determined by measuring the sample length using a constant speed extension type tensile tester.
Measured at 100 mm and tensile speed of 100 mm/min, and calculated from the following formula. Elastic recovery rate = B-C/B x 100 (%) However, here, B is 80% of the elongation at cutting of the nonwoven fabric.
After measuring the value of B, the load is removed and C indicates the elongation relative to the length of the sample before measurement after being left for 1 minute. 1 Creation of raw cotton Raw cotton A Copolymerized polyester (A) is a polyethylene terephthalate based polyester copolymerized with 5.1 mol% of SIP component and has an intrinsic viscosity of 0.470, and polyester (B) is polyethylene terephthalate with an intrinsic viscosity of 0.687 at a composite weight ratio of 1:1. Spun as a side-by-side composite fiber, and then combine the undrawn yarns so that the toe denier after drawing is 350,000 deniers,
Stretching temperature 67℃, stretching speed 125m/min, stretching ratio 2.3
Stretching is carried out at 100%, followed by tension heat treatment at a temperature of 162
After heat treatment at °C, the fibers were mechanically crimped using a staff box and cut to 51 mm to obtain staple fibers. Other spinning conditions are spinning temperature 297℃,
The number of spinneret holes was 351, the take-up speed was 1175 m/min, and the discharge rate was 218 g/min. Raw cotton B (for comparison) The undrawn yarn used in raw cotton A was stretched at a stretching temperature of 67°C, a stretching speed of 125 m/min, and a stretching ratio of 2.45 times, followed by relaxation heat treatment at 145°C for 5 minutes. , and cut to 51 mm to obtain staple fibers. Incidentally, crimp appeared naturally without using staff avocados. Raw cotton C (for comparison) Polyethylene terephthalate-based polyester copolymerized with 2.6 mol% of SIP component as the copolymerized polyester (A), with an intrinsic viscosity of 0.536, and polyethylene terephthalate with an intrinsic viscosity of 0.687 as the polyester (B), in the same manner as raw cotton A. After spinning (however, the discharge rate was 251 g/min), it was drawn at a draw ratio of 2.7 times in the same manner as raw cotton A, and mechanically crimped to obtain a staple fiber. Raw cotton D Copolymerized polyester (A) is a polyethylene terephthalate polyester copolymerized with 3.3 mol% of the SIP component, with an intrinsic viscosity of 0.536, and polyester (B) is polyethylene terephthalate with an intrinsic viscosity of 0.553, and spun and stretched in the same manner as raw cotton A. A staple fiber was also obtained by applying mechanical crimp (discharge rate: 245 g/min, tension heat treatment temperature: 130° C., stretching ratio: 2.6 times). Table 1 shows the yarn properties of the raw cotton obtained by the above method.

[Table] 2 Creation of web (for Examples 1, 4, 5 and Comparative Examples 1 and 2) Staple fiber obtained in 1) and Unitika Co., Ltd.
Polyester binder fiber “Meltei” 2d×51
After mixing the cotton in an opener at a weight ratio of 85:15, a web with a basis weight of 35 g/m ² was prepared using a roller carding machine. Among them, when raw cotton B was used (this is referred to as Comparative Example 1), it was not possible to create a satisfactory web with many neps and undefinated parts, and the web creation was abandoned. (In the case of Examples 2 and 3 and Comparative Example 3) The staple fibers obtained in Examples 1 to 3 in 1) and other cotton were mixed in an opener in the weight proportions shown in Table 2, and then mixed with a roller. Weight 35 with type carding machine
A web of g/m ² was prepared.

[Table] 3 Heat treatment (Execution-1 to 4, Comparative Examples-2 and 3)
Primary heat treatment is performed using a heat roll with a surface temperature of 115℃.
Next, a free heat treatment was performed for 5 minutes at 160° C. to obtain a nonwoven fabric. (In the case of Example 5) The produced web was subjected to free heat treatment in a thermal oven at 135° C. for 5 minutes to obtain a nonwoven fabric. 4 Physical property measurement results of nonwoven fabric Table 3 shows the physical properties of the nonwoven fabric prepared as described above, which were measured by the method described above.

[Table] (Effects of the Invention) As described above, the nonwoven fabric of the present invention has high elongation properties and also has excellent elastic recovery properties.

Claims (1)

[Claims] 1 3 structural units having a metal salt sulfonate group
The non-woven fabric is composed of two components: copolymerized polyester (A) mainly composed of ethylene terephthalate units copolymerized with ~6 mol% and polyethylene terephthalate (B), and the composite fiber has a number of crimps of 18/25 mm or less before heat treatment. 45% by weight or more of the total fibers to be mixed with the composite fibers and different polyester fibers and/or low melting point polyester binder fibers to form a web, and then heat treated at 130°C or higher to crimp the composite fibers. A method for producing a polyester-based highly elongated nonwoven fabric, characterized by producing a nonwoven fabric with a number of 50 pieces/25 mm or more.