JPH05140850A - Production of polyester elastic nonwoven fabric and spinning dope therefor - Google Patents

Abstract

PURPOSE:To obtain the title stretchable nonwoven fabric excellent in elastic recovery rate by melt spinning of a dope prepared by incorporating a specific copolyester elastomer with a polyolefin and inorganic fine powder followed by opening the resultant fibers into a web. CONSTITUTION:The objective elastic nonwoven fabric can be obtained by melt spinning of a dope prepared by incorporating (A) a copolyester elastomer from (1) a polyester consisting mainly of polybutylene terephthalate and (2) a polyether consisting mainly of polytetramethylene glycol with (B) 1-10wt.% of a polyolefin and (C) 1-8wt.% of inorganic fine powder followed by opening the resultant fibers into a web.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a stretchable nonwoven fabric made of copolyester elastic fibers and a spinning dope for use in the method. More specifically, the elastic polyester having stretchability is a polyester-based elastic nonwoven fabric having improved stretchability because the polymer itself exhibits tackiness, and therefore the filaments are sticky between filaments during yarn formation and the spreadability is poor. And a spinning dope for use therein.

[0002]

2. Description of the Related Art Polybutylene terephthalate (hereinafter referred to as P
A non-woven fabric using a polyester-based elastomer in which a polyester containing BT as a main component and a polyether containing polytetramethylene glycol (hereinafter abbreviated as PTMG) as a main component are copolymerized is known (JP-A-57).
-82553, or JP-A-3-8855). However, this polyester-based elastomer has high tackiness and has a problem in openability after spinning. In the above-mentioned patent application, it is described that a single yarn number of 30 or less is appropriate due to the problem of openability. On the other hand, JP-A-58-12904
No. 6, gazette proposes an elastic composition in which 0.01 to 15 parts by weight of an inorganic fine powder that does not affect the polyester elastomer crystallinity is added. However, regarding the problem of tackiness and the nonwoven fabric, Nothing touched.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a copolyester elastic polymer comprising a polyester containing polybutylene terephthalate (PBT) as a main component and a polyether containing polytetramethylene glycol (PTMG) as a main component. The purpose is to provide a stretchable polyester-based elastic non-woven fabric which is manufactured with good operability without sticking between filaments and without impairing the characteristics of an elastic body.

[0004]

In order to solve the above-mentioned problems, the present invention provides a copolymerized polyester elastomer comprising a polyester containing polybutylene terephthalate as a main component and a polyether containing polytetramethylene glycol as a main component. The present invention provides a spinning stock solution for polyester-based elastic non-woven fabrics, characterized in that 1 to 10 wt% of polyolefin and 1 to 8 wt% of inorganic fine powder are added. The present invention also provides a method for producing a polyester-based elastic nonwoven fabric, which comprises melt-spinning using the above spinning dope and then opening and web-forming.

The present invention will be described in detail below. The polyester elastomer referred to in the present invention is disclosed in JP-A-56-
A polymer described in Japanese Patent No. 118911,
It is a copolymerized polymer composed of polyester whose main component is PBT and polyether whose main component is PTMG. The main component of the polyester component is terephthalic acid as a dicarboxylic acid component, and the main component of PBT is butanediol as a diol component, and other copolymerization components such as polyethylene terephthalate, polyethylene isophthalate, polybutylene isophthalate, or polybutylene. Adipate or the like may be copolymerized, for example, in an amount of about 10 parts by weight as long as the spinnability and elastic properties are not impaired.

On the other hand, as the polyether component, PTMG consisting of tetramethylene glycol is the main component, and the number average molecular weight is 1000 to 30 from the viewpoint of spinnability and elasticity.
00 is preferable. Other copolymers of ethylene glycol, diethylene glycol, trimethylene glycol, etc. may be used.

The polyester elastomer referred to in the present invention is a copolyester / polyether composed of these, and the copolymerization ratio of these is usually 90 to 20% by weight of the polyester component, preferably 80 to 40% by weight, The polyether component is 10 to 80% by weight, preferably 20 to
A copolymer composed of 60% by weight is preferable. Within this range, the fiber has a melting point suitable for melt spinning and, at the same time, exhibits excellent elastic recovery rate. In addition to these main components, a small amount of a colorant, an antioxidant, a heat-resistant agent, a matting agent, etc. may be added depending on the intended use. In addition,
Copolyester / polyether is ethane tetrachloride /
The relative viscosity measured at a temperature of 20 ° C. at a 1/1 weight ratio of phenol is preferably 1.3 to 3.0.

When the above polymer is used for spinning, the filaments usually have tackiness, so that, for example, in the so-called jet spinning method, the filaments adhere to each other in the jet, and in the subsequent fiber-spreading process, the filaments are completely adhered to each other. The problem of not opening the fiber occurs. Further, in the so-called spin draw method, an adhesion phenomenon still occurs when an oil agent is applied and stretching is performed between the rollers, and it is not possible to open the fiber and it is possible to manufacture only a non-woven fabric having a non-uniform weight. For this reason, in the present invention, polyolefin and inorganic fine powder are added to the above-mentioned polymer to improve it.

Polyolefin greatly contributes to the reduction of tackiness. It is assumed that the polyester-based elastomer and the polyolefin have no affinity with each other, but because of the lack of affinity, the polyolefin is exposed on the surface of the filament and the tackiness is eliminated. Examples of the polyolefin include general-purpose polypropylene, high-density polyethylene, linear low-density polyethylene, ethylene / propylene copolymer and the like. Although the reason is not clear, polypropylene and linear low-density polyethylene are more effective by eliminating tackiness. Further, the molecular weight, melt viscosity, etc. of these polyolefins are not particularly limited, but those having a melt index of 5-80 are preferable considering the spinnability, but the viscosity, copolymerization ratio, etc. of the polyester elastomer used. Determined by That is, when the PBT content is high, a relatively high molecular weight polyolefin can be used because the polyester elastomer has a high melting point, but when the PTMG content is high,
Due to the low melting point, relatively low molecular weight polyolefins must be used.

In the present invention, 1 to 10% by weight of these polyolefins is added to the polyester elastomer. Of course, considering the characteristics of the fiber to be obtained, and the amount of the polyolefin added depends on the copolymerization ratio of the polyester component or PTMG, but when the amount added is less than 1% by weight, the adhesiveness between filaments is increased. If the effect of reducing the above is poor, and conversely is more than 10% by weight, the spinnability will be poor or the elastic recovery rate of the obtained polyester fiber will be inferior.

The inorganic fine powder has a great influence on the fiber-opening property, and titanium oxide is a typical example thereof, but other examples include magnesium stearate, calcium carbonate,
Examples include calcium phosphate. These inorganic fine powders are added to the polyester elastomer in an amount of 1 to 8% by weight. Particularly, 1 to 5% by weight is preferable. When it is less than 1% by weight, the adhesiveness between filaments is reduced due to the added polyolefin, but it does not lead to the improvement of the openability, so that only a non-uniform nonwoven fabric having a basis weight can be obtained. On the other hand, when the amount is more than 8% by weight, the pressure of the spinneret increases naturally, there is a problem in spinning for a long time, and a problem remains in operation.

In the present invention, the effect is exhibited only when the above-mentioned polyolefin and inorganic fine powder are used in combination.
If either of them is lacking, problems will occur in the adhesion between filaments or the openability. These polyester elastomers, polyolefins and inorganic fine powders can be blended in any process. For example, during the polymerization process of polyester elastomer, inorganic fine powder is added to ethylene glycol or tetramethylene glycol as a slurry and polymerized, and when the polymerization is completed, polyolefin is added into the polymerization kettle and blended. A method may be used, or a method may be used in which a polyester-based elastomer containing an inorganic fine powder is chipped during the polymerization step and then a chipped polyolefin is blended. Further, a method may be used in which a polyester-based elastomer is polymerized, a fine inorganic powder is blended with polyolefin to prepare a master chip, and both are blended. Of these, the first and second methods are not so preferable because they require cleaning of the polymerization kettle, and the third method is the most effective method from the viewpoint of operation and cost. When blending the chipped polymer, it is better to use a spinning machine stand equipped with a so-called static mixer for the kneading effect.

Next, a method for producing a nonwoven fabric using these polymers will be described. The polymer blended by the above method is produced by a conventional melt spinning apparatus. That is, using an extruder type melt spinning device,
15 ~ from the melting point of the polyester elastomer used
After being melted at a high temperature of 80 ° C. and discharged from the spinneret, it is accompanied by a high-speed air stream, and preferably jetted at a speed of 1000 m / min or more. This accelerates and orients the elastic fibers in a high velocity air stream. However, if the jetting speed exceeds 4000 m / min, the elastic recovery rate of the obtained fiber is impaired because the yarn is cut or the orientation is excessively increased. Then, the obtained filaments are uniformly opened through a fiber opening device and collected in a sheet shape by a net conveyor to prepare a fiber web having a predetermined thickness and a filament arrangement.

Another method is to stretch between rollers without using a high-speed air stream. After being discharged from the spinneret, it is taken up by a roller having a speed of 200 m / min or more and 2000 m / min or less, and then stretched with another roller. In the stretching, a non-heated or heated roller is used depending on the composition of the polymer. Similar to the jet spinning, the stretching ratio is 1.1 to 3.0 times as the stretching ratio because the characteristics of the elastic fiber are lost if the orientation is too high. In addition, relaxation heat treatment is performed if necessary. Then, the fibers are opened in the same manner as above and collected in a sheet shape to form a fiber web.

After that, the fiber web employs a method in which the constituent filaments are bonded together by heat using an embossing roller. Specifically, the formed fiber web is introduced into an embossing roller. For example, it is a method of passing a fiber web between a pair of embossing rollers or passing a fiber web between a pair of rollers including an embossing roller and a flat roller. The temperature of the embossing roller is most affected by the copolymerization composition of the polyester elastomer used, but the embossing roller is pressed at a temperature 5 ° C. or more lower than the melting point of the polyester elastomer. Further, the total area of the area pressed by the convex portion of the embossing roller is preferably 3% or more and 20% or less, and preferably 4% or more and 15%, with respect to the total area of the fiber web.
The following is more preferable. When the pressed area is less than 3%, the fusion between the fibers is insufficient, and the shape retention of the resulting nonwoven fabric is not preferable. On the other hand, when it is higher than 20%, the area corresponding to the concave portion of the embossing roller becomes small, the length by which the elastic fiber freely expands and contracts becomes short, and the elasticity tends to decrease. In addition, in the case of manufacturing by these methods, there is no problem even if the treatment is continuously performed to the web formation of the fiber.

The elastic polyester non-woven fabric having stretchability can be obtained by the above method, but the shape, number, and basis weight of the filaments forming the fiber web are not particularly limited, but the filament denier is 0.2. -10, weight is 5-2
A range of 00 g / m ² is preferred. The elastic polyester nonwoven fabric having such elasticity exhibits a numerical value of 35% or more as the instantaneous elastic recovery rate at the time of elongation of 50%, and it has not only elasticity but also drapeability, and heat resistance,
It also has excellent resistance to moist heat.

[0017]

The present invention will be described in detail with reference to the following examples. In the examples, the measuring method and measuring condition for each item are as follows. The melt index is ASTM-D-
1238 (E), the melt flow rate is ASTM-
Determined according to D-1238 (L). Nonwoven fabric strength,
Elongation is Tensilon TM-4 manufactured by Toyo Baldwin
Using -1-100, according to the method described in JIS-L-1096A, a sample piece having a sample length of 10 cm and a width of 5 cm was measured at a tensile rate of 10 cm / min. Also, KS Powerful
The basis weight was measured and calculated from the following formula in order to convert the basis weight to 100 g / m ² . KS strength = 100 × tensile strength (kg) / basis weight (g / m ² ) The elastic recovery rate of the nonwoven fabric is 50% elongation under the conditions of 10 cm / min pulling speed, cut into a shape with a sample length of 10 cm and a width of 5 cm. It was calculated from the recovery rate.

Example 1 PBT and PTMG having a number average molecular weight of 2000 were polycondensed in a weight ratio of 45/55. This polymer had a melting point of 183 ° C. and a relative viscosity of 2.04. A polyester elastomer having such characteristic values and a melt index of 26 g containing 25% by weight of titanium oxide.
The amount of linear low-density polyethylene added for / 10 minutes was changed as shown in Table 1, and chip blending was performed. For comparison, only polyethylene having a melt index of 26 g / 10 min without titanium oxide and titanium oxide alone were used. Then, spinning was performed at a spinning temperature of 210 ° C. using an extruder type melt spinning device equipped with a static mixer.

Under these conditions, a spinneret having a hole diameter of 0.3φ and a number of holes of 300 was used to discharge 150 from the spinneret.
It was sprayed with a high-speed air stream provided below the cm and collected on a net conveyor to form a fiber web. At this time, the single yarn denier was adjusted to 4d and the basis weight was adjusted to 50 g / m ² . As the operability at this time, spinnability, adhesiveness between filaments, and openability were evaluated from the uniformity of the areal weight, and the results are shown in Table 1. Further, this fiber web was introduced into a clearance calender machine manufactured by Yuri Roll Co., Ltd. The lower roller of the clearance calender was a flat roller made of steel, and the upper roller was an embossing roller having many convex portions. The protrusions of this embossing roller had a density of 10 pieces / cm ² , and the total area of the protrusions was 4.2% with respect to the entire area of the roller. Also,
The conditions for introducing the fiber web into the clearance calender are as follows: introduction speed 5 m / min, linear pressure between rollers 27 kg.
/ Cm, and the roller temperature was 170 ° C. After embossing with a clearance calender, a hot air circulation type heat treatment machine was used to perform relaxation heat treatment for 1 minute at the same atmospheric temperature as the roller temperature to obtain a stretchable elastic nonwoven fabric. The physical properties of this stretchable elastic nonwoven fabric are also shown in Table 1.

[Table 1] As is clear from the results shown in Table 1, No.
Nos. 4, 5, and 6 had no problem in operability, and excellent elastic recovery rates were obtained. However, Comparative Example No. in which neither was added.
In No. 1, adhesion occurred between filaments and a fiber web could not be formed. In Comparative Example No. 2 in which only polyethylene was added, the openability was poor and the web had a non-uniform basis weight. Further, in Comparative Example No. 3 in which only titanium oxide was added, tackiness was observed and the basis weight was non-uniform. Comparative Example N in which too much polyethylene was added
In No. 7, only the characteristic that the elastic recovery rate was inferior was obtained.

Example 2 The same polyester elastomer as in Example 1 was used, and the melt flow rate containing 50% of titanium oxide was 30 g /
Polypropylene elastomer of 10 minutes was blended with polyester elastomer at various addition amounts as shown in Table 2, and under the same conditions as in Example 1, single yarn denier was 3d and basis weight was 30 g.
A fiber web was obtained such that the fiber web had a thickness of / cm ² . Then, embossing was performed using the clearance calender in Example 1 under the same conditions except that the total area of the protrusions was 8% of the total area of the roller. The physical properties of the stretchable nonwoven fabric thus obtained are shown in Table 2.

[Table 2] As is clear from Table 2, No. 8 and 9 which are examples of the present invention
A non-woven fabric having good operability and an excellent elastic recovery rate was obtained. However, in Comparative Example No. 10 in which too much titanium oxide was added, fluff was generated during spinning, and at the same time, the pressure of the spinneret was sharply increased, and only a nonwoven fabric having an inferior elastic recovery rate was obtained.

As described above, the polyester elastic nonwoven fabric according to the present invention is a copolymerized polyester elastomer composed of polyester containing polybutylene terephthalate as a main component and polyether containing polytetramethylene glycol as a main component. In addition, a small amount of polyolefin and inorganic fine powder are added, and during spinning, there is no sticking between filaments, good openability, it is possible to form a web with a uniform basis weight, and by processing it into a non-woven fabric. Also has a characteristic that the elastic recovery rate is extremely good, and can be suitably used mainly for a pad material, an interlining material, a stretch tape and the like.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location D04H 3/00 D 7199-3B (72) Inventor Fumio Matsuoka 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Stock Shikisha Central Research Institute

Claims (2)

[Claims] 1. A polyolefin copolymer 1 to 10% by weight, and a fine inorganic powder 1 to 8% by weight, based on a copolymerized polyester elastomer composed of a polyester containing polybutylene terephthalate as a main component and a polyether containing polytetramethylene glycol as a main component. % Of a polyester-based elastic nonwoven fabric spinning solution. 2. A method for producing a polyester-based elastic nonwoven fabric, which comprises melt-spinning using the spinning dope according to claim 1 and then opening and web-forming.