JP3502686B2 - Biodegradable composite fiber - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable composite fiber which can be produced with good spinnability and is excellent in biodegradability.

[0002]

2. Description of the Related Art Conventionally, when a biodegradable fiber is produced by a melt spinning method, a method in which a spun filament is cooled and solidified by blowing a cooling air and then drawn is adopted.

However, many polymers having excellent biodegradability have a crystallization temperature lower than room temperature and a slow crystallization rate, and the spun yarn is insufficiently cooled only by ordinary cooling air blowing. Therefore, there was a problem that it could not be solidified and sticking occurred.

As a solution to this problem, it is conceivable to lower the cooling air temperature, lengthen the cooling time, or increase the cooling air velocity. However, the method of lowering the cooling air temperature still fails to achieve sufficient cooling, and there is a device limitation in lengthening the cooling time, and the method of increasing the cooling air velocity causes yarn swaying and uneven yarn. There was a problem.

Although various biodegradable fibers have been proposed, fibers having different biodegradation rates are desired depending on the use.

[0006]

DISCLOSURE OF THE INVENTION The present invention comprises a biodegradable polymer having a low crystallization temperature and a slow crystallization rate,
The present invention intends to provide a biodegradable conjugate fiber which can be manufactured with good spinnability and is excellent in biodegradability.

[0007]

Means for Solving the Problems The present invention is to solve the above-mentioned problems, and the gist thereof is a composite fiber composed of component A and component B having biodegradability and different crystallization rates. In the fiber cross section, the component B is intermittently surrounded by the component A, both of which are continuous in the fiber axial direction.
And component B has a higher crystallization rate than component A,
Occupies the central part, and component B occupies the tip part or all of the leaf part
Biodegradability characterized by having a multi-leaf cross-section
Composite fiber.

The present invention will be described in detail below.

As the component A, the following polymers are preferably used. Polybutylene succinate (PBS) and polyethylene succinate (PE) in a molar ratio range of 85/15 to 65/35
S), a copolymer with polybutylene adipate (PBA) or polybutylene sebacate (PBSe). PES, PBS, P in the molar ratio range of 100/0 to 85/15
Copolymer with BA or PBSe. Polycaprolactone (PCL).

As the component B, a molar ratio of 100/0 to
90/10 PBS and PES, PBA or PBS
A copolymer with e is preferably used.

In the polymer of component A, if the proportion of PBS is higher than the above range, the biodegradability is poor, and if it is low, the fiber quality of the obtained fiber is poor. In the above polymer, if the proportion of PES is less than the above range, the fiber quality of the obtained fiber will be inferior.

Furthermore, if the proportion of PBS of component B is less than the above range, sticking occurs and the spinnability is poor.

The polymer constituting the conjugate fiber preferably has a number average molecular weight of 20,000 or more, preferably 30,000 or more, from the viewpoints of spinnability and properties of the obtained fiber.

It is desirable that the polymer to be used for spinning contains 0.01 to 5% by weight, preferably 0.05 to 2% by weight, of an inorganic crystal nucleating agent such as calcium carbonate, titanium dioxide, alumina, silica and talc.

The melt spinning temperature varies depending on the melting point and the molecular weight of the polymer used, but it is preferably 140 to 280 ° C. If the spinning temperature is lower than 140 ° C, melt extrusion is difficult, and if it exceeds 280 ° C, the polymer is remarkably decomposed, and it becomes difficult to obtain high-strength fiber.

The composite form is composed of component A having different crystallization rates.
And the component B, and the circumference of the component A in the fiber cross section.
The component B intermittently surrounds the fiber, both of which are fiber axes.
Direction is continuous, and component B has a higher crystallization rate than component A
Fast, component A occupies the center, and component B the tip of the leaf
Or, it must have a multi-lobed cross-sectional shape that occupies the whole . Among biodegradable polymers, generally, a polymer having good crystallinity has a slow decomposition rate, while a polymer having low crystallinity has excellent biodegradability. When a polymer with good crystallinity such as component B is used for the single-type or core-sheath type sheath, the entire fiber surface is covered with it, so sticking is prevented and the spinnability is improved, but it becomes biodegradable. Inferior. But,
When a polymer having low crystallinity such as component A is used, sticking occurs and the spinnability deteriorates. Therefore, by intermittently surrounding the component A with the component B and exposing both components to the fiber surface, it is possible to obtain a fiber having excellent spinnability and excellent biodegradability.

In the conjugate fiber of the present invention, the fiber cross section has a multi-lobed cross section, and the component A occupies the central part and the component B occupies the tip part or all of the leaf part. When the fiber cross section is a multi-lobed cross section, the surface area per unit weight of the polymer is larger than that of a fiber having a circular cross section, and the spun yarn can be cooled easily. Further, since the component B having a high crystallization rate is present in the protrusions on the fiber surface, sticking is less likely to occur and the spinnability is improved. Further, the use of the multi-leaf cross-section fiber makes it excellent in gloss and bulkiness.

1 and 2 are schematic cross-sectional views of specific examples of the conjugate fiber of the present invention, in which 1 indicates component A and 2 indicates component B.

Hollow fibers may be used, and if they are hollow fibers, the cooling property is further improved.

The composite weight ratio of component A and component B is from 1/1 to
It is preferably 5/1. If the amount of component B is more than the above range, the biodegradability is poor, and if it is less, sticking is likely to occur and the spinnability is deteriorated. Furthermore, by changing this composite ratio, it becomes possible to obtain fibers having different biodegradation rates.

The melt spun yarn is cooled by an annular or horizontal spraying installed directly below the spinneret. The yarn that has been solidified by cooling is 300 to 3500 m after applying the spinning oil.
The film is drawn at a speed of 1 / minute and is continuously drawn after being wound or without being wound. As the spinning oil agent, a conventional spinning oil agent for polyester fibers can be used.

Stretching is carried out at room temperature or in a single stage or in multiple stages using a heat roller or the like. In order to obtain a high-strength fiber, it is desirable to draw in multiple stages, and a hot plate or a hot oven may be used between the heating roller and the drawing roller during the second drawing step. Particularly, when dimensional stability is required, it is desirable to add a constant length heat treatment or a relaxation heat treatment subsequent to the stretching. In this way, it is possible to produce a composite fiber having a certain yarn quality performance and biodegradability that can be practically used.

[0023]

EXAMPLES Next, the present invention will be specifically described by way of examples. The measurement and evaluation methods are as follows. (a) Spinnability The wound multifilament yarn is opened by static electricity, and there is no sticking between single yarns, and the yarns are completely separated.
The case where even a part of the single yarn showed sticking was evaluated as x. (b) Tensile strength and elongation Measured according to JIS L 1013. (c) Biodegradability For 3 months from July to October, the sample was buried in the soil and then taken out to measure the strength.
◎, strength retention rate is 50%
Those with less than 50 were evaluated as ◯, and those with 50% or more were evaluated as x.

Example 1 As component A, a copolymer of PBS and PES having a number average molecular weight of 35,000 and a molar ratio of 85/15, and as component B, PBS having a number average molecular weight of 40,000 and 0.1% by weight of titanium dioxide. The added product is supplied to an extruder-type melt spinning machine, and at a spinning temperature of 170 ° C, melt spinning is performed from a spinneret having a fiber cross section as shown in Fig. 1 and cooled and solidified by horizontal spraying. After granting 4
Take-up at a speed of 00m / min and continuously draw at the 1st stage draw ratio
Stretching was carried out at a draw ratio of 1.5, a second draw ratio of 2.7, and a total draw ratio of about 4.1 to obtain 110d / 36f composite fibers.

Examples 2-4 and Comparative Examples 1-2 Under the conditions shown in Table 1, the yarn was made in the same manner as in Example 1.

Example 5 As component A, a copolymer of PBS and PES having a number average molecular weight of 35,000 and a molar ratio of 65/35, and as component B, PBS having a number average molecular weight of 35,000 and a molar ratio of 90/10. And PES
Using 0.1% by weight of titanium dioxide added to the copolymer with and supplying it to the extruder type melt spinning machine, the spinning temperature was 170 ° C, and the fiber cross-section was melted from the spinneret as shown in Fig. 2. After spinning and horizontal spraying to cool and solidify, apply the water-based emulsion oil agent, take it off at a speed of 400 m / min, and continuously draw at a first draw ratio of 1.5 times, a second draw ratio of 2.6 times, and a total draw ratio. Stretching was carried out at about 3.9 to obtain 110d / 36f composite fibers.

Examples 6 to 8 and Comparative Examples 3 to 4 Under the conditions shown in Table 1, yarn was produced in the same manner as in Example 5. Table 1 shows the characteristic values of the conjugate fibers obtained in Examples 1 to 8 and Comparative Examples 1 to 4.

[0028]

[Table 1]

In Examples 1 to 8, there was no sticking between single yarns,
A bicomponent fiber having good properties was obtained. Further, in Examples 5 to 8, although the thread quality performance was slightly low, the biodegradability was very good. On the other hand, in Comparative Examples 1, 3 and 4, sticking occurred between the single yarns, and Comparative Example 2
Then, only those with poor biodegradability were obtained.

[0030]

EFFECTS OF THE INVENTION According to the present invention, a biodegradable conjugate fiber which can be produced with good spinnability and is excellent in biodegradability is provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a specific example of the conjugate fiber of the present invention.

FIG. 2 is a schematic cross-sectional view of another specific example of the conjugate fiber of the present invention.

[Explanation of symbols]

1 component A 2 component B

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigemitsu Murase 23, Uji Kozakura, Uji City, Kyoto Prefecture Unitika Ltd. Central Research Laboratory (56) Reference JP-A-6-212548 (JP, A) JP-A-6-248516 (JP, A) JP 5-93316 (JP, A) JP 5-186954 (JP, A) JP 6-248518 (JP, A) JP 3-269111 (JP, A) 58) Fields investigated (Int.Cl. ⁷ , DB name) D01F 8/00-8/18

Claims (2)

(57) [Claims] 1. A composite fiber comprising biodegradable component A and component B having different crystallization rates, wherein component B is intermittently surrounded around component A in the fiber cross section,
All of them are continuous in the fiber axis direction, and component B is
The crystallization speed is faster than that of the component A, and the component A occupies the central portion,
Component B has a multi-lobed cross-sectional shape that occupies the tip or all of the leaf portion.
A biodegradable composite fiber characterized by being present. 2. The component A is  (1) Molar ratio 85 / 15 ~ 65 / 35 Range of
Polybutylene succinate and polyethylene succine
Polybutylene adipate or polybutylene seba
Copolymer with cate, (2) Molar ratio  100 / 0 ~ 85 / 15 Demon
Enclosed polyethylene succinate and polybutylene succine
Sheet, polybutylene adipate or polybutylene
Copolymer with bacate or (3) Polycaprolactone
And component B is in molar ratio  100 / 0 ~ 90 / Ten Range of polybutyric
Len succinate and polyethylene succinate, polyb
Co-weight with Tylene Adipate or Polybutylene Sebacate
The biodegradable conjugate fiber according to claim 1, which is a united body.