WO2023128012A1 - Biodegradable composite fiber and method for manufacturing same - Google Patents

Abstract

The objective of the present invention is to provide a biodegradable composite fiber having excellent biodegradability and spinnability. The present invention is directed to a biodegradable composite fiber comprising: 30-70 wt% of a core portion containing polylactic acid (PLA); and 30-70 wt% of a sheath portion containing polylactic acid (PLA).

Description

Biodegradable composite fiber and method for producing the same

The present invention relates to biodegradable composite fibers and methods for preparing them.

The importance of degradable polymers has already been sufficiently recognized according to the needs of the times to prevent environmental pollution. The environmental pollution problem caused by the disposal of industrial and household polymers has acted as a major obstacle to the polymer industry, which has been recognized as a great advantage in the existing durability. The country legally mandates the use of these environmentally degradable polymers.

Synthetic polymers that are biodegradable include poly carprolacton (PCL), polylactic acid (PLA), aliphatic polyester (AP), and polyglycolic acid (PGA). Although these have relatively excellent physical properties, PLA fibers are brittle and have a rough touch, and have a high shrinkage rate, shrinking by more than 50% during heat treatment, and thus have poor fairness.

In addition, PLA has a problem in that biodegradation occurs slowly in a daily environment because biodegradation proceeds under certain conditions of 60 ° C. or higher and 70% or higher moisture.

A technical problem of the present invention is to provide a biodegradable composite fiber having excellent biodegradability and excellent spinnability.

One embodiment of the present invention is 30 to 70% by weight of the core portion containing polylactic acid (PLA); It is a biodegradable composite fiber containing; and 30 to 70% by weight of the sheath portion containing low melting point polylactic acid (PLA).

The core portion may be composed of 50 to 95 wt% of polylactic acid (PLA), 3 to 45 wt% of polyhydroxyalkanoate (PHA), and 0.1 to 10 wt% of a compatibilizer.

The sheath part may be composed of 50 to 95% by weight of low melting point polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA), and 0.1 to 10% by weight of a compatibilizer.

The fineness of the biodegradable composite fiber is 0.5 to 20 denier, and the length may be 3 to 150 mm.

The biodegradable composite fiber may have a radioactive rating of S or A as measured by the following measurement method.

[measurement method]

Radiation rating: Evaluate the number of troubles such as trimming and drop that occur during one hour per 1 position of radiation by classifying them into S to D.

(S: 0 times, A: 1 time, B: 2-3 times, C: 4-6 times, D: 7 times or more)

Another embodiment of the present invention is 1) preparing a core part melt by mixing and melting polylactic acid (PLA), polyhydroxyalkanoate (PHA) and PET crosslinking agent; 2) mixing and melting low-melting polylactic acid (PLA), polyhydroxyalkanoate (PHA) and a compatibilizer to prepare a sheath part melt; 3) preparing composite fibers by spinning the melted core part and the melted sheath part at a temperature of 230 to 310° C. at a speed of 500 to 2,000 m/min; 4) drawing the obtained unstretched conjugate fibers; And 5) heat-treating the stretched fibers at 40 ~ 100 ℃; biodegradable composite fiber manufacturing method comprising a.

The melt core part may be a mixture of 50 to 95% by weight of polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA), and 0.1 to 10% by weight of a compatibilizer.

The cis part solvent may be a mixture of 50 to 95% by weight of low melting point polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA), and 0.1 to 10% by weight of a compatibilizer.

The present invention is formed of a sheath part and a core part, and the biodegradability of PLA can be further improved by including low melting point PLA and PHA in the sheath part and using PLA and PHA together in the core part.

The present invention can improve biodegradability and radioactivity by including each component in a specific content.

The present invention can improve the spinnability of the fiber by improving compatibility by including a compatibilizer.

1 is a flow chart showing the manufacturing method of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

Included in the biodegradable composite fiber of the present invention, polylactic acid (PLA), low melting point polylactic acid (PLA), polyhydroxyalkanoate (PHA) and the compatibilizer have the following characteristics.

The polylactic acid (PLA) has a melting point of 150 to 190 ° C, a melt index (MI) at a temperature of 190 ° C and a load of 2.16 kg may be 3 to 20 g / 10 min, and the melting point of the low-melting polylactic acid (PLA) is 110 ~ 150 ℃, the temperature of 190 ℃, the melt index (MI) at a load of 2.16kg may be 3 to 20g / 10min.

In addition, the low-melting polylactic acid included in the sheath part can be melted at a lower temperature than the core part when the biodegradable composite fiber according to the present invention is formed into a product, for example, when it is made of nonwoven fabric, and thus thermal bonding efficiency By increasing the, it is possible to improve the durability of the product.

The polyhydroxyalkanoate (PHA) has better biodegradability than PLA, and thus can further improve the biodegradability of biodegradable composite fibers compared to the case of using only PLA. ℃, the melt index (MI) at a load of 2.16kg may be 2 to 10g / 10min.

In addition, the compatibilizer is added to increase the compatibility of the PLA and PHA and to improve the spinnability and physical properties of the composite fiber by increasing the compatibility of the low melting point PLA and PHA, an epoxy-based compound, a styrene-based compound, It may consist of a carbodiimide-based compound, an ester-based compound, or a mixture thereof, and may include a multifunctional component, preferably an ester-based compound, and more preferably stearic acid.

Hereinafter, the present invention will be described in detail.

One embodiment of the present invention is 30 to 70% by weight of the core portion containing polylactic acid (PLA); It is a biodegradable composite fiber containing; and 30 to 70% by weight of the sheath portion containing low melting point polylactic acid (PLA).

In the present invention, the core portion may be made of 50 to 95% by weight of polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA), and 0.1 to 10% by weight of a compatibilizer, preferably polylactic acid ( PLA) 75 to 92% by weight, polyhydroxyalkanoate (PHA) 5 to 20% by weight and compatibilizer 0.5 to 5% by weight. In the core part, if the content of PHA exceeds 45% by weight, it is not easy to form yarn during fiber manufacturing, and the manufacturing cost is too high, making it uneconomical. Biodegradability may occur.

In addition, the core portion may be 30 to 70% by weight, preferably 45 to 55% by weight, based on the total content of the composite fiber. When the content of the core part is out of the above range, the difference in melt flowability between the core part and the sheath part increases, and thus the spinnability may be reduced due to a difference in rheology.

In addition, if the content of the compatibilizer is less than 0.1% by weight, radioactivity is reduced, and if it exceeds 10% by weight, biodegradability may appear at a level similar to that of existing 100% PLA products.

In the present invention, the sheath portion may be made of 50 to 95% by weight of low melting point polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA) and 0.1 to 10% by weight of a compatibilizer, preferably poly 75 to 92% by weight of lactic acid (PLA), 5 to 20% by weight of polyhydroxyalkanoate (PHA), and 0.5 to 5% by weight of a compatibilizer. If the content of PHA in the sheath part exceeds 45% by weight, it is not easy to form yarn during fiber manufacturing, and the manufacturing cost is too high, making it uneconomical. gender may appear.

In addition, if the content of the compatibilizer is less than 0.1% by weight, radioactivity is reduced, and if it exceeds 10% by weight, biodegradability may appear at a level similar to that of existing 100% PLA products.

In addition, the sheath portion may be 30 to 70% by weight, preferably 45 to 55% by weight, based on the total content of the composite fiber. When the content of the sheath part is out of the above range, the difference in melt flowability between the core part and the sheath part increases, and thus the spinnability may decrease due to a difference in rheology.

The fineness of the composite fiber according to the present invention may be 0.5 to 20 denier, the length may be 3 to 150 mm, preferably the fineness may be 2 to 10 denier, and the length may be 10 to 100 mm.

When the fineness and length of the conjugate fibers are out of the above ranges, processing into products such as non-woven fabrics is not easy, so the above ranges are preferable.

In addition, the composite fiber may be a single fiber, and may be made of various types of fibers or nonwoven fabrics such as air through, thermal point bond, spunlace, needle punch, and airlaid nonwoven fabric.

The biodegradable composite fiber may have a radioactivity level of S or A as measured by the following measurement method, and if it is less than A level, the radioactivity is not good, and thus the quality may be deteriorated.

[measurement method]

Radiation rating: Evaluate the number of troubles such as trimming and drop that occur during one hour per 1 position of radiation by classifying them into S to D.

(S: 0 times, A: 1 time, B: 2-3 times, C: 4-6 times, D: 7 times or more)

1 is a flow chart showing the manufacturing method of the present invention.

Referring to Figure 1, another embodiment of the present invention is 1) preparing a core part melt by mixing and melting polylactic acid (PLA), polyhydroxyalkanoate (PHA) and a compatibilizer; 2) mixing and melting low-melting polylactic acid (PLA), polyhydroxyalkanoate (PHA) and a compatibilizer to prepare a sheath part melt; 3) preparing composite fibers by spinning the melted core part and the melted sheath part at a temperature of 230 to 310° C. at a speed of 500 to 2,000 m/min; 4) drawing the obtained unstretched conjugate fibers; and 5) heat-treating the stretched fibers at 40 to 100° C.; and a biodegradable composite fiber manufacturing method.

The melt core part may be a mixture of 50 to 95% by weight of polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA), and 0.1 to 10% by weight of a compatibilizer, preferably polylactic acid. (PLA) 75 to 92% by weight, polyhydroxyalkanoate (PHA) 5 to 20% by weight and 0.5 to 5% by weight of a compatibilizer may be mixed.

In addition, the cis part solvent may be mixed with 50 to 95% by weight of low melting point polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA) and 0.1 to 10% by weight of a compatibilizer, preferably More specifically, it may be prepared by mixing 75 to 92% by weight of low-melting polylactic acid (PLA), 5 to 20% by weight of polyhydroxyalkanoate (PHA), and 0.5 to 5% by weight of a compatibilizer.

When the melt of the core part and the melt of the sheath part are mixed in an amount outside of the above range, the difference in melt flowability between the core part and the sheath part increases and the spinnability may be lowered due to a difference in rheology, so the above range is preferable. .

In addition, the melting temperature at the time of preparing the melt may be 230 ~ 310 ℃, specifically may be 250 ~ 290 ℃. If the melting temperature is less than 230 ° C, the mixing is not easy because each component is not completely melted, and if it exceeds 310 ° C, the melt flow of the PLA polymer is high and there is a problem with radioactive defects, and the above range is preferable. The time for preparing the melt is not limited as long as each component is sufficiently mixed.

The step 3) is a step of producing a composite fiber by spinning the core part melt and the sheath part melt at a temperature of 230 ~ 310 ℃, respectively, at a speed of 500 ~ 2,000 m / min, preferably 250 ~ 310 ℃ It can be spun at a speed of 500 to 1,500 m/min at a temperature, and the spinning can use a spinneret for sheath-core type composite fibers.

If the spinning temperature is less than 230 ° C, the melt flowability of the polymer is lowered, thereby lowering the spinnability, and if it exceeds 310 ° C, the decomposition or melt flow of the polymer is increased, resulting in poor spinnability, and the above range is preferable. .

In addition, if the spinning speed is less than 500 m/min or more than 2,000 m/min, there is a problem in that spinnability is lowered, and the above range is preferable.

In addition, the stretching may be performed at a stretching ratio of 1.2 to 6.0, preferably at a stretching ratio of 2 to 4.

If the draw ratio is less than 1.2, it is difficult to maintain the tension of the spinning tow, resulting in poor drawability due to non-uniform drawing and sagging of the spinning tow. .

At this time, water (Water bath), steam (Steam chest), hot air (Hot air chest) can be used as a heat source for the stretching process, but is not limited thereto.

Finally, the step of heat treating the stretched fiber is a step for removing stress generated after stretching, fixing the crystal structure of the fiber, and improving toughness by increasing strength, and may be performed at 40 to 100 ° C. there is. If the heat treatment temperature exceeds 100 ° C or is less than 40 ° C, there are problems in that drying is poor, stress relief is insufficient, or strength is lowered, so the above range is preferable.

Hereinafter, specific embodiments according to the present invention will be described.

Sheath and core resin

Resins used in the core part and the sheath part are shown in Table 1 below, and stearic acid was used as a compatibilizer.

Examples 1 to 7

PLA, PHA, and stearic acid were melted at 260°C to prepare a core portion melt, and low-melting PLA, PHA, and stearic acid were melted at 230°C to prepare a sheath portion melt.

Next, the melt was spun at a temperature of 260° C. at a speed of 1,000 m/min using a spinneret for sheath-core type composite fibers, and the resulting unstretched fibers were drawn at a draw ratio of 3.0. Thereafter, a heat treatment was performed at 50° C., and a fiber having 5 denier was cut to a size of 40 mm to prepare a composite fiber. Conditions according to the manufacture of composite fibers are shown in Table 2 below.

Comparative Examples 1 to 7

PLA, PHA, and stearic acid were melted at 260°C to prepare a core portion melt, and low-melting PLA, PHA, and stearic acid were melted at 230°C to prepare a sheath portion melt.

Next, the melt was spun at a temperature of 260° C. at a speed of 1,000 m/min using a spinneret for sheath-core type composite fibers, and the resulting unstretched fibers were drawn at a draw ratio of 3.0. Thereafter, a heat treatment was performed at 50° C., and a fiber having 5 denier was cut to a size of 40 mm to prepare a composite fiber. Conditions according to the manufacture of composite fibers are shown in Table 3 below.

Experimental Example 1

The biodegradation characteristics of Examples 1 to 7 and Comparative Examples 1 to 7 were measured through the following measurement method, and the results thereof are shown in Table 4 below.

[measurement method]

Biodegradability: Measure the biodegradability for 60 days according to the ASTM D5338 standard

Referring to Table 4 of the present invention, in the case of containing 5 to 20% by weight of PHA that promotes biodegradation (Examples 1 to 7), the biodegradability exceeded 65%, but only PLA was included (Comparative Example 7), When the PHA is included in an amount of 1% by weight (Comparative Example 4), it can be seen that the biodegradability is less than 65%.

In addition, in the case of including 15% by weight of the compatibilizer (Comparative Example 5), it can be confirmed that the biodegradability is less than 60% due to the low content of the biodegradable resin.

Experimental Example 2

The radioactivity levels of Examples 1 to 7 and Comparative Examples 1 to 7 were measured through the following measurement method, and the results thereof are shown in Table 5 below.

[measurement method]

Radiation rating: Evaluate the number of troubles such as trimming and drop that occur during one hour per radiation position by classifying them into S to D (S: 0 times, A: 1 time, B: 2-3 times, C: 4-6 times) times, D: 7 times or more)

Referring to Table 5 of the present invention, when the weight ratio of the sheath part and the core part is 3 to 7: 7 to 3 (Examples 1 to 3 and 5 to 7), it can be confirmed that the radioactivity is S or A, but PHA When the content of is 20% by weight (Example 4), it can be confirmed that the radioactivity is B.

In addition, when the weight ratio of the sheath part and the core part is 2:8 or 8:2 (Comparative Examples 1 and 2), it can be confirmed that the radioactivity is not good as C due to the difference in the ratio of the sheath part and the core part, and the PHA content is In the case of 50% by weight (Comparative Example 3), it can be seen that radioactivity is very low as D.

In addition, when the compatibilizer is not included (Comparative Example 6), it is also not easy to mix PLA and PHA, so it can be confirmed that the radioactivity is as low as C.

As described above, the biodegradable composite fiber according to the present invention includes PLA and PHA in the core part and low-melting PLA and PHA in the sheath part, thereby improving biodegradability, and including a compatibilizer, thereby increasing compatibility to form a composite fiber. It is possible to increase the spinnability of the fiber.

Above, preferred embodiments of the present invention have been described in detail. The description of the present invention is for illustrative purposes, and those skilled in the art will understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Therefore, the scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning, scope and equivalent concepts of the claims are interpreted as being included in the scope of the present invention. It should be.

Claims (8)

1. 30 to 70% by weight of a core portion containing polylactic acid (PLA); and

   30 to 70% by weight of the sheath portion containing low melting point polylactic acid (PLA);

   Biodegradable composite fibers comprising a.
2. According to claim 1,

   the core part,

   Polylactic acid (PLA) 50 to 95% by weight, polyhydroxyalkanoate (PHA) 3 to 45% by weight and a biodegradable composite fiber characterized in that consisting of 0.1 to 10% by weight of a compatibilizer.
3. According to claim 1,

   The sheath part,

   A biodegradable composite fiber comprising 50 to 95% by weight of low-melting polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA) and 0.1 to 10% by weight of a compatibilizer.
4. According to claim 1,

   The biodegradable composite fiber, characterized in that the fineness of the biodegradable composite fiber is 0.5 ~ 20 denier, the length is 3 ~ 150mm.
5. According to claim 1,

   The biodegradable composite fiber is a biodegradable composite fiber, characterized in that the radioactivity grade measured by the following measuring method is S or A.

   [measurement method]

   Radiation rating: Evaluate the number of troubles such as trimming and drop that occur during one hour per 1 position of radiation by classifying them into S~D.

   (S: 0 times, A: 1 time, B: 2-3 times, C: 4-6 times, D: 7 times or more)
6. 1) mixing and melting polylactic acid (PLA), polyhydroxyalkanoate (PHA), and a compatibilizer to prepare a core part melt;

   2) mixing and melting low-melting polylactic acid (PLA), polyhydroxyalkanoate (PHA) and a compatibilizer to prepare a sheath part melt;

   3) preparing composite fibers by spinning the melted core part and the melted sheath part at a temperature of 230 to 310° C. at a speed of 500 to 2,000 m/min;

   4) drawing the obtained unstretched conjugate fibers; and

   5) heat-treating the drawn fibers at 40 to 100 ° C;

   Biodegradable composite fiber manufacturing method comprising a.
7. According to claim 6,

   The core part melt is a biodegradable composite fiber characterized in that polylactic acid (PLA) 50 to 95% by weight, polyhydroxyalkanoate (PHA) 3 to 45% by weight and a compatibilizer 0.1 to 10% by weight are mixed manufacturing method.
8. According to claim 6,

   The cis part solvent is biodegradable, characterized in that a mixture of 50 to 95% by weight of low melting point polylactic acid (PLA), 3 to 45% by weight of polyhydroxyalkanoate (PHA) and 0.1 to 10% by weight of a compatibilizer Composite fiber manufacturing method.

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