JP3506521B2 - Biodegradable core-sheath composite long fiber and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a biodegradable core-sheath composite continuous fiber which is biodegradable, has excellent cooling properties of spun yarn and mechanical properties of fibers, and has thermal adhesiveness. The present invention relates to a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, as fibers having biodegradability, cellulosic fibers represented by cotton and hemp, or
A protein fiber represented by silk can be mentioned. However, these so-called natural fibers do not have thermal adhesiveness because they are non-thermoplastic, and at the same time, they are not decomposed in a short period of time and the product form is maintained for a long period of time, and in terms of protection of natural environment and living environment. Not preferable.

As biodegradable long fibers, there are known cupra rayon long fibers, viscose rayon long fibers obtained by a wet spinning method, and natural chemical fibers such as chitin and collagen. However, since these conventional biodegradable long fibers have low mechanical strength and are hydrophilic, the mechanical strength is significantly decreased when they are absorbed by water and wet, and the material itself is non-thermoplastic, so that they are heat-bonded. There were various problems such as not having sex.

Therefore, biodegradable conjugate fibers have been proposed in, for example, Japanese Patent Application Laid-Open No. 5-93316, "Microbiodegradable composite fiber" and Japanese Patent Application Laid-Open No. 5-93318, "Microbiodegradable composite fiber and nonwoven fabric thereof". . However, since these biodegradable conjugate fibers have a low melting point and a crystallization temperature of the resin, the cooling property of the spun yarn is inferior, and troubles such as the yarns sticking to each other occur, which is caused by this. The obtained fiber was inferior in uniformity.

[0005]

The present invention solves the above problems, has biodegradability, is excellent in the cooling property of spun yarn and the mechanical performance of fibers, and has thermal adhesiveness. It is an object of the present invention to provide a biodegradable composite filament and a method for producing the same.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have arrived at the present invention after conducting daily examinations. That is, the present invention has the following structures.

1. The core component is made of polybutylene succinate, the sheath component is made to copolymerize the repeating unit element constituting another aliphatic polyester to the repeating unit element constituting polybutylene succinate, and the copolymerization amount ratio of butylene succinate Is a core-sheath composite long fiber made of a copolymer having a content of 65 to 95 mol%, characterized in that at least a copolymer constituting the sheath component contains a crystal nucleating agent. .

2. A biodegradable core-sheath composite long fiber, wherein the sheath component is a copolymer of repeating unit elements constituting polybutylene succinate and polyethylene succinate.

3. A biodegradable core-sheath composite continuous fiber, wherein the sheath component is a copolymer of repeating unit elements constituting polybutylene succinate and polybutylene adipate.

4. A biodegradable core-sheath composite continuous fiber, characterized in that both the core component and the sheath component are made of a polymer having a melt flow rate value of 10 to 70 g / 10 min. However,
The melt flow rate value is measured according to ASTM-D-123.
According to the method described in 8 (E).

[0011]

[0012]

5. Polybutylene succinate as a core component, using a copolymer of repeating unit elements constituting polybutylene succinate as a sheath component and repeating unit elements constituting another aliphatic polyester, and at least a crystal nucleating agent as a sheath component. It is added and guided from the melting point (Tm) of the copolymer constituting the sheath component through the spinneret for core-sheath compounding.
Biodegradation characterized by melt-spinning at a spinning temperature [T (° C.)] satisfying the formula (1) , cooling the spun yarn, and once stretching or continuously stretching without winding. Of producing a flexible core-sheath composite long fiber. Tm + 40 ≦ T ≦ Tm
+150 (1)

Next, the present invention will be described in detail. The core-sheath composite continuous fiber in the present invention needs to be polybutylene succinate as the core component, and the repeating unit element that constitutes the polybutylene succinate as the sheath component constitutes another aliphatic polyester. It is necessary that the unit elements are copolymerized. Examples of the aliphatic polyester other than polybutylene succinate include, for example, poly (α-hydroxy acid) such as polyglycolic acid and polylactic acid, or a copolymer of repeating unit elements constituting these, and poly (α-hydroxy acid). ε-caprolactone), poly (ω-hydroxyalkanoates) such as poly (β-propiolactone), and poly-
Poly (β-hydroxyalkanoates such as 3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaproate, poly-3-hydroxyheptanoate, poly-3-hydroxyoctanoate. And a copolymer of a repeating unit element constituting these and a repeating unit element constituting poly-3-hydroxyvalerate or poly-4-hydroxybutyrate. In addition, as a polycondensation polymer of glycol and dicarboxylic acid, for example, polyethylene oxalate, polyethylene adipate, polyethylene azate, polybutylene oxalate, polyethylene succinate, polybutylene adipate, polybutylene sebacate, polyhexamethylene sebacate. , Polyneopentyl oxalate, or copolymers of the repeating unit elements constituting them. Among the above aliphatic polyesters, the repeating unit elements constituting polyethylene succinate and polybutylene adipate are particularly preferably used because of their excellent spinnability and biodegradability.

Further, in the copolymer constituting the sheath component of the core-sheath composite long fibers in the present invention, it is necessary that the copolymerization ratio of butylene succinate is 65 to 95 mol%. If the copolymerization amount ratio of butylenesac sheet exceeds 95 mol%, the biodegradability is deteriorated, which is not preferable. On the other hand, when the copolymerization amount ratio of butylene succinate is less than 65 mol%, the biodegradability is improved, but even if the crystal nucleating agent is added, the cooling property of the spun yarn is inferior and further obtained. It is not preferable because the mechanical performance of the yarn is reduced.

The polymers and copolymers as the core component and the sheath component in the present invention have a number average molecular weight of 20,000.
Those having a value of 0 or more, preferably 40,000 or more, and more preferably 60,000 or more are preferable in terms of the spinnability and the characteristics of the obtained yarn. Further, in order to increase the degree of polymerization, chain extension may be carried out with a small amount of diisocyanate, tetracarboxylic acid dianhydride or the like.

Further, the melt flow rate value (hereinafter, abbreviated as MFR value) of the polymer in the present invention is 10 to 70 g.
/ 10 minutes is preferable. However, the melt flow rate value in the present invention is ASTM-D-1238.
It is measured according to the method described in (E). MFR
When the value is less than 10 g / 10 minutes, the viscosity is too high, the spun yarn is not thinned smoothly, and only thick fibers having poor uniformity are obtained, which is not preferable. vice versa,
When the MFR value exceeds 70 g / 10 minutes, the viscosity is too low, so that yarn breakage occurs frequently in the spinning process, the operability is poor, and only poor uniformity is obtained, which is not preferable.

In the present invention, the polymers and copolymers constituting the core component and the sheath component described above may be, if necessary, for example, matting agents, pigments, light stabilizers and heat stabilizers. Various additives such as antioxidants may be added within a range that does not impair the effects of the present invention.

The cross section of the composite continuous fiber in the present invention is required to have a core-sheath form. That is, when the core component polymer of the present invention is used alone, although the cooling properties of the spun yarn and the mechanical properties of the obtained yarn are excellent, the biodegradability becomes poor. On the other hand, when the sheath component polymer of the present invention is used alone, the biodegradability is excellent, but since the crystallization temperature of the polymer is low in the yarn making process, adhesion occurs between spun yarns and the yarn is collected. Difficult to do. By using the core-sheath structure of the present invention, the core component improves mechanical performance, the sheath component promotes biodegradability, and a crystal nucleating agent is added to the sheath component for the first time. It is possible to obtain long fibers which are free from adhesion between the fibers and have excellent mechanical performance and biodegradability.

Further, since the sheath portion has a low melting point, a product constituted by the biodegradable composite continuous fiber of the present invention is subjected to a heat treatment at a temperature near the melting point of the sheath portion in a higher processing,
The heat-bonded fiber can be efficiently obtained without impairing the flexibility.

In the biodegradable core-sheath composite continuous fiber of the present invention, the composite ratio, that is, the weight ratio of the sheath component to the core component is preferably 1/5 to 5/1, and 1/2 to 2 /.
It is more preferably 1. When the weight ratio of the sheath portion to the core component 1 exceeds 5, the biodegradability is excellent, but the strength of the fiber decreases and the cooling property of the spun yarn also decreases, which is not preferable. On the contrary, when the weight ratio of the sheath portion to the core component 5 is less than 1, although the cooling property of the spun yarn is improved, the cross-sectional shape of the yarn is not stable and the biodegradability is deteriorated, which is preferable. Absent.

By the way, in the present invention, it is necessary to add a crystal nucleating agent to at least the sheath component of the core-sheath composite long fibers. That is, since a copolymer having low crystallinity is hard to solidify after melt-spinning without adding a crystal nucleating agent, adhesion is apt to occur between spun yarns. The crystal nucleating agent is added in the polymerization step or the melting step of the copolymer constituting the sheath component, but at this time, it should be dispersed as uniformly as possible in order to improve the mechanical performance and the uniformity of the obtained yarn. Is preferred.

The crystal nucleating agent is not particularly limited as long as it is a powdered inorganic substance and does not dissolve in the melt, but talc, calcium carbonate, titanium oxide, silica gel, magnesium oxide and the like are preferable. Used.

The average particle size of the inorganic powder as a crystal nucleating agent is 5
It is preferably not more than μm. When the average particle size exceeds 5 μm, it tends to be difficult to obtain finer fibers, or the filtration filter in the spinneret having a plurality of discharge holes is apt to be clogged, resulting in a spinning operation. There is a tendency for the sex to decrease. For these reasons, the average particle size of the inorganic powder as the crystal nucleating agent is 5 μm or less, preferably 4 μm or less, more preferably 3 μm or less.

The bulk specific volume of the inorganic powder as a crystal nucleating agent is 2
It is preferably from 10 to cc / g, more preferably from 3 to 8 cc / g. The bulk specific volume is the volume of the inorganic powder per unit weight. The larger the bulk specific volume, the larger the surface area of the inorganic powder and the greater the effect as a crystal nucleating agent. If the bulk specific volume of the inorganic powder is less than 2 cc / g, the effect as a crystal nucleating agent is reduced, and therefore the amount of the crystal nucleating agent added (content in the polymer) must be increased, The mechanical strength of the resulting fiber is reduced. Further, it is difficult to produce an inorganic powder having a bulk specific volume of more than 10 cc / g, and when such an inorganic powder is tried to be obtained, the cost of the inorganic powder rises, and the cost of the obtained long fiber also rises. Becomes

[0026]

[0027]

The biodegradable core-sheath composite continuous fiber in the present invention preferably has a single yarn fineness of 1.5 to 10 denier. If the single yarn fineness is less than 1.5 denier, the spun yarn has excellent cooling properties, but there are problems such as frequent yarn breakage during spinning and poor productivity. On the contrary, when the single yarn fineness exceeds 10 denier, the productivity is improved, but the cooling property and biodegradability of the spun yarn are deteriorated, which is not preferable. For these reasons, the single yarn fineness is more preferably 2 to 6 denier.

It is important that the biodegradable core-sheath composite continuous fiber of the present invention has a tensile strength of 4.0 g / d or more. If the tensile strength is less than 4.0 g / d, it is difficult to withstand actual use depending on the application, which is not preferable.

Next, a method for producing the biodegradable core-sheath composite continuous fiber of the present invention will be described. First, for both the core component and the sheath component, the above-mentioned polymer, that is, polybutylene succinate for the core component and butylene succinate for the sheath component has a copolymerization ratio of 65 to 95 mol%. Melt spinning is performed using a copolymer of butylene succinate and other repeating unit constituents of an aliphatic polyester. At this time, at least the sheath component has a polymerization step.
Alternatively, it is necessary to add and disperse the crystal nucleating agent in the melting step . The spinning temperature must be within the range that satisfies the expression (1) . When the spinning temperature is higher than the value defined by the formula (1) , the cooling property of the spun yarn is inferior and the spun yarn adheres to the spun yarn, which is not preferable. In addition, the spinning temperature
When it is lower than the value defined by the formula (1) , the polymer is not sufficiently melted and the spinnability is remarkably deteriorated, which is not preferable. The spun yarn discharged from the spinneret for core-sheath composite fibers is cooled by a known cooling device, and after applying a finishing oil agent, it is treated with an undrawn yarn through a take-up roller at a spinning speed of 350 to 2000 m / min. To do. After winding this unstretched yarn once,
Using a multi-stage or multi-stage drawing machine, the total draw ratio of 0.5
Stretching is performed at a stretch ratio of 0.85 times to obtain the target stretched yarn. The undrawn yarn can be continuously drawn without winding.

[0031]

The biodegradable core-sheath composite continuous fiber of the present invention has excellent mechanical performance and biodegradability by improving mechanical performance in the core component and promoting biodegradation performance in the sheath component. It is something that has a combination. Furthermore, by including a crystal nucleating agent in at least the sheath component, it is possible to promote the cooling effect of the spun yarn and prevent adhesion of the spun yarn.

Further, when the biodegradable core-sheath composite continuous fiber of the present invention is produced, by selecting the range of the present invention as the spinning temperature, it is possible to prevent the spun yarn from adhering to each other and to provide excellent uniformity. The biodegradable core-sheath composite continuous fiber can be obtained.

[0033]

EXAMPLES Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

In the examples, each physical property value was measured by the following methods. MFR value (g / 10 minutes); ASTM D1238
It measured according to the method as described in (E).

Melting point (° C.); measured using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., Ltd. with a sample weight of 5 mg and a heating rate of 20 ° C./min, and the maximum melting endothermic curve obtained The temperature giving the value was taken as the melting point.

Crystallization temperature (° C.); using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., and a sample weight of 5 m
g, the rate of temperature increase was measured at 20 ° C./min, and the temperature that gives the maximum value of the solidification exothermic curve obtained was taken as the crystallization temperature.

Coolability: The presence or absence of adhesion of the undrawn yarn obtained through the take-up roller was visually determined.

Tensile strength (g / d), elongation (%); JI
The measurement was performed according to the method described in SL-1013. That is, the sample was stretched using a constant-speed elongation type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.).
The obtained load value at break (g) was converted per unit thickness, and the average value was taken as the tensile strength (g / d) of the fiber.
Further, the average value of the elongation rate at break (%) obtained at the same time was defined as the elongation rate (%). In each of these prescriptions, the number of measurements was 20 and the value was shown as an average value.

Biodegradability: A sample of 10 g of the obtained fiber was buried in soil and excavated after 1, 3, 6 and 12 months,
The tensile strength of the fiber was measured in a standard state, and the tensile strength after embedding was compared with the tensile strength before embedding in the soil, and the strength retention rate shown in the following formula was evaluated. Strength retention rate (%) = (tensile strength after embedding / tensile strength before embedding) × 100

Example 1 As a core component, the MFR value was 27 g / 10 minutes and the melting point was 114.
℃, crystallization temperature of 75 ℃ polybutylene succinate chips, as a sheath component, MFR value 32g / 10 minutes, melting point 9
Using a butylene succinate / ethylene succinate = 85/15 mol% copolymer chip having a crystallization temperature of 9 ° C. and a crystallization temperature of 49 ° C., 1.5 wt% of talc satisfying the formula (1) is used as a crystal nucleus in the sheath component. It was added as an agent to produce a core-sheath composite long fiber. That is, the polymer chip was melted at 170 ° C. which satisfies the formula (2) by using an extruder type melt extruder, and the melted polymer chip was passed through a spinneret for core-sheath composite having 24 spinning holes with a hole diameter of 0.4 mm. After melt-spinning with a hole discharge rate of 1.3 g / min and cooling the spun yarn with a cooling device,
It was wound as an undrawn yarn through a take-up roller having a spinning speed of 1200 m / min. This yarn is then drawn at a draw ratio of 3.
It was drawn at 1 time to obtain a drawn yarn of brand 75d / 24f. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 2 As a sheath component, the MFR value is 33 g / 10 minutes and the melting point is 86.
Same as Example 1 except that a butylene succinate / ethylene succinate = 65/35 mol% copolymer chip having a crystallization temperature of 28 ° C. and a single hole discharge rate of 1.2 g / min was used. Melt spinning, and the obtained yarn is wound up in the same manner as in Example 1 and drawn at a draw ratio of 2.9 times to give a brand 75
A drawn yarn of d / 24f was obtained. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 3 As a sheath component, MFR value is 29 g / 10 minutes, melting point 112
C. and crystallization temperature 73.degree. C. Butylene succinate / ethylene succinate = 95/5 mol% copolymer chips were used and the same as in Example 1 except that the single hole discharge rate was 1.4 g / min. Melt spinning, and the obtained yarn is wound up in the same manner as in Example 1 and drawn at a draw ratio of 3.4 to give a brand 75d.
A drawn yarn of / 24f was obtained. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 4 As a sheath component, MFR value is 32 g / 10 minutes, melting point 110
Melt spinning was performed in the same manner as in Example 1 except that a butylene succinate / butylene adipate = 85/15 mol% copolymer chip having a crystallization temperature of 32 ° C. and a crystallization temperature of 32 ° C. was used. Similarly, it was wound and drawn at a draw ratio of 3.1 times to obtain a drawn yarn of brand 75d / 24f. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 5 Obtained by melt-spinning in the same manner as in Example 1 except that 0.25% by weight of talc was added as a crystal nucleating agent and the single hole discharge rate was 1.4 g / min. The yarn was wound up in the same manner as in Example 1 and drawn at a draw ratio of 3.4 to obtain a drawn yarn of brand 75d / 24f. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 6 Melt impeding was carried out in the same manner as in Example 1 except that 2.5% by weight of talc was added as a crystal nucleating agent, and the obtained yarn was wound in the same manner as in Example 1 and the draw ratio was increased. It was drawn at 3.1 times to obtain a drawn yarn of brand 75d / 24f. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 7 A drawn yarn was obtained by a one-step method after melt spinning in the same manner as in Example 1 except that the single hole discharge rate was set to 1.5 g / min. That is, it was drawn under the condition of a draw ratio of 3.0 times between a take-up roller having a speed of 1500 m / min and a drawing roller having a speed of 4500 m / min to obtain a drawn yarn of brand 75d / 24f. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 8 A polymer chip having a core component polymer having an MFR value of 50 g / 10 minutes and a sheath component polymer having an MFR value of 52 g / 10 minutes was used, and a single hole discharge rate was set to 1.5 g / min. Spinning temperature is 140 ℃
Melt spinning was performed in the same manner as in Example 1 except that the above was performed, and the obtained yarn was wound in the same manner as in Example 1 and the draw ratio was 3.6.
Stretching was performed twice to obtain a stretch of brand 75d / 24f. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Example 9 A polymer chip having a core component polymer having an MFR value of 15 g / 10 min and a sheath component polymer having an MFR value of 17 g / 10 min was used, and a single hole discharge rate was 1.4 g / min. Spin temperature is 230 ℃
Melt spinning was performed in the same manner as in Example 1 except that the above was set, and the obtained yarn was wound in the same manner as in Example 1 and the draw ratio was 3.4.
Stretching was performed twice to obtain a stretch of brand 75d / 24f. Table 1 shows production conditions, physical properties of the yarn, and biodegradability.

Comparative Example 1 Single phase long fibers were produced using polybutylene succinate chips having an MFR value of 27 g / 10 minutes, a melting point of 114 ° C. and a crystallization temperature of 75 ° C. That is, using the polymer chip, the spinning temperature was 190 ° C., and the single hole discharge rate was 1.4 g /
Melt spinning in the same manner as in Example 1 except that a single-phase spinneret was passed through, and the obtained yarn was wound in the same manner as in Example 1 and stretched at a draw ratio of 3.4. / 24f
The drawn yarn of was obtained. Table 2 shows production conditions, physical properties of the yarn, and biodegradability.

Comparative Example 2 MFR value 32 g / 10 minutes, melting point 86 ° C., crystallization temperature 2
Butylene succinate / ethylene succinate at 5 ° C =
Single phase long fibers were made using 65/35 mol% copolymer chips. That is, melt spinning was performed in the same manner as in Example 1 except that the polymer chip was used and the single-phase spinneret was passed through. The manufacturing conditions are shown in Table 2.

Comparative Example 3 As a sheath component, the MFR value was 32 g / 10 minutes and the melting point was 84.
Melt spinning was performed in the same manner as in Example 1 except that a butylene succinate / ethylene succinate = 60/40 mol% copolymer chip having a crystallization temperature of 22 ° C. was used.
The manufacturing conditions are shown in Table 2.

Comparative Example 4 Example 1 except that talc was not added as a crystal nucleating agent.
Melt spinning was performed in the same manner as in. The manufacturing conditions are shown in Table 2.

[0053]

[Table 1]

As is clear from Table 1, since Example 1 has the core-sheath composite form and satisfies all the constitutions of the present invention, the cooling property and the spinnability of the spun yarn are also good,
The obtained core-sheath composite long fibers had sufficient strength and excellent biodegradability. In Example 2, since the butylene succinate copolymerization ratio of the sheath component was lower than that in Example 1, the obtained core-sheath composite continuous fiber had a sufficient strength, although it was slightly inferior to that in Example 1, and also had spinnability. It was good and had excellent biodegradability. In Example 3, since the butylene succinate copolymerization amount ratio of the sheath component is higher than that in Example 1, the obtained core-sheath composite long fiber has an excellent biodegradability although it is slightly inferior to Example 1, The property was also good and had sufficient strength. In Example 4, the core-sheath composite long fibers obtained with good spinnability had sufficient strength and excellent biodegradability. In Example 5, since the amount of talc added was smaller than that in Example 1, the cooling property was slightly inferior, but the spunability was good, and the obtained core-sheath composite long fibers had sufficient strength and excellent biodegradability. It was something that had. In Example 6, since the amount of talc added was larger than that in Example 1, the obtained core-sheath composite continuous fiber had a sufficient strength, although it was slightly inferior to that in Example 1, and had good spinnability and excellent biodegradation. It had performance. In Example 7, the spun yarn was stretched without winding, and thus the obtained core-sheath composite continuous fiber had a sufficient strength, although it was slightly inferior to that in Example 1, and had good spinnability and excellent rawness. It had a decomposition performance.
In Example 8, since the spinning temperature was lower than that of Example 1, the obtained core-sheath composite continuous fiber had a sufficient strength, although it was slightly inferior to that of Example 1, and had good spinnability and excellent biodegradability. I had one. In Example 9, since the spinning temperature is higher than that of Example 1, the cooling property is slightly inferior, but the spunability is also good, and the obtained core-sheath composite filament has sufficient strength and excellent biodegradability. It is a thing.

[0055]

[Table 2]

On the other hand, as is clear from Table 2, Comparative Example 1 has sufficient strength because it is composed only of polybutylene succinate and has good spinnability,
It is inferior in biodegradability. Since Comparative Example 2 was composed only of a copolymer of butylene succinate and ethylene succinate, the spinnability of the spun yarn was poor because of poor cooling, and the yarn could not be obtained. In Comparative Example 3, since the copolymerization ratio of ethylene succinate to butylene succinate was high, the sheath component of the spun yarn was not sufficiently cooled and adhered to the yarn, so that the yarn could not be obtained. In Comparative Example 4, since the crystal nucleating agent was not added, the spun yarn was in close contact and the yarn could not be obtained.

[0057]

As described above, according to the present invention, it is possible to provide a biodegradable core-sheath composite continuous fiber which solves problems such as adhesion and has excellent mechanical strength and thermal adhesiveness.

By making the cross section of the fiber into a core-sheath form, the core component improves the mechanical performance and the sheath component promotes the biodegradation performance to obtain a long fiber excellent in the mechanical performance and the biodegradation performance. be able to. Furthermore, by including a crystal nucleating agent in the polymer constituting at least the sheath component, the cooling effect of the spun yarn can be promoted and the adhesion of the spun yarn can be prevented.

Further, in producing the biodegradable core-sheath composite continuous fiber of the present invention, by selecting the range of the present invention as the spinning temperature, the adhesion of the spun yarn is prevented, and the raw material excellent in uniformity is obtained. Thus, degradable core-sheath composite long fibers can be obtained.

The long fibers according to the present invention are extremely suitable as sanitary materials, life-related materials and industrial materials. Moreover, since this long fiber has biodegradability, it is completely biodegradable and disappears after its use, which is also beneficial from the viewpoint of protecting the natural environment, or it can be reused by, for example, composting it into a fertilizer. It is also useful from the perspective of resource reuse.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-93316 (JP, A) JP-A-7-324227 (JP, A) JP-A-8-246241 (JP, A) JP-A-4- 194026 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) D01F 8/00-8/18

Claims (5)

(57) [Claims] 1. A repeating unit element comprising a polybutylene succinate as a core component and a polybutylene succinate as a sheath component and a repeating unit element constituting another aliphatic polyester as a copolymer, and a butylene succinate. Is a core-sheath composite long fiber made of a copolymer having a copolymerization amount ratio of 65 to 95 mol%, characterized in that at least the copolymer constituting the sheath component contains a crystal nucleating agent. Core-sheath composite filament. 2. The biodegradable core-sheath composite continuous fiber according to claim 1, wherein the sheath component is a copolymer of repeating unit elements constituting polybutylene succinate and polyethylene succinate. 3. The biodegradable core-sheath composite filament according to claim 1, wherein the sheath component is a copolymer of repeating unit elements constituting polybutylene succinate and polybutylene adipate. 4. The biodegradation according to any one of claims 1 to 3, wherein both the core component and the sheath component are made of a polymer having a melt flow rate value of 10 to 70 g / 10 minutes. Core-sheath composite filaments. However, the melt flow rate value is measured according to the method described in ASTM-D-1238 (E). 5. Polybutylene succinate as the core component,
Using a copolymer of a repeating unit element constituting polybutylene succinate and a repeating unit element constituting another aliphatic polyester as a sheath component, adding a crystal nucleating agent to at least the sheath component, and spinning for core-sheath composite Guided from the melting point (Tm) of the copolymer constituting the sheath component through the die
Biodegradation characterized by melt-spinning at a spinning temperature [T (° C.)] satisfying the formula (1) , cooling the spun yarn, and once stretching or continuously stretching without winding. Of producing a flexible core-sheath composite long fiber. Tm + 40 ≦ T ≦ Tm
+150 (1)