KR102395895B1 - Biodegradable composite fiber and non-woven fabric including the same - Google Patents

Abstract

Disclosed are a biodegradable composite fiber and a nonwoven fabric comprising the same. The disclosed biodegradable composite fiber comprises a core comprising a polylactic acid (PLA) resin, and a sheath comprising a blend of PLA resin and other resins.

Description

Biodegradable composite fiber and non-woven fabric including the same

Disclosed are a biodegradable composite fiber and a nonwoven fabric comprising the same. More specifically, a biodegradable composite fiber having a high crystallinity and low shrinkage, and a nonwoven fabric including the same are disclosed.

Recently, worldwide demand for high-functional bioplastic materials that can replace fossil raw materials, can reduce carbon dioxide, and do not cause environmental pollution problems is rapidly increasing.

The development of bioplastics can dramatically reduce carbon dioxide emissions compared to petrochemical products at the current technological level, so it is highly likely to develop into a core industry of low-carbon green growth industries.

Polylactic acid (hereinafter referred to as PLA), a type of bioplastic, is a 100% biodegradable aliphatic polyester. It is relatively easy to produce and has similar properties and applications to existing plastics, so it has a high commercialization potential compared to other bioplastics. There is an advantage.

Fibers or nonwoven fabrics manufactured using such PLA have an environmentally friendly advantage of biodegradability, but exhibit high stiffness and high shrinkage due to structural limitations and low crystallinity. Since these properties eventually cause shrinkage of products in the state of fibers or nonwovens, a technology capable of improving the crystallinity of PLA fibers and nonwovens is urgently required.

旣 As a known technique, there is a method of improving the crystallinity of fibers or nonwovens by introducing a high draw ratio, but it is difficult to apply to the spunbond nonwoven process, which is a process that has no choice but to apply a low draw ratio by adjusting the draw ratio with cooling air pressure There is this.

In addition, a method of improving the crystallinity by mixing with a polyolefin-based resin is known, but there is a disadvantage that the fiber or nonwoven fabric to which it is applied is not 100% biodegradable.

[Prior art literature]

[Patent Literature]

Patent Document 1: Korean Patent No. 10-1526636 (Announcement Date: 2015.06.05)

One embodiment of the present invention provides a biodegradable composite fiber having a high crystallinity and low shrinkage.

Another embodiment of the present invention provides a nonwoven fabric including the composite fiber.

One aspect of the present invention is

a core comprising a polylactic acid (PLA) resin; and

A composite fiber comprising a sheath comprising a blend of PLA resin and other resins is provided.

The other resin may include polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polyhydroxyalkanoate (PHA), or a combination thereof.

A weight ratio of the core to the sheath may be 50 to 90:10 to 50.

The content of the other resin in the sheath may be 10 to 50 parts by weight based on 100 parts by weight of the PLA resin.

The crystallinity of the composite fiber may be 30% or more.

The shrinkage rate of the composite fiber may be 20% or less.

Another aspect of the present invention is

It provides a nonwoven fabric comprising the composite fiber.

The nonwoven fabric may be a spunbond nonwoven fabric.

The composite fiber according to an embodiment of the present invention has high crystallinity and low shrinkage as well as 100% biodegradability.

1 is a cross-sectional view of a composite fiber according to an embodiment of the present invention.

Hereinafter, a composite fiber according to an embodiment of the present invention will be described in detail.

In the present specification, the "crystallization degree of the composite fiber" may be calculated according to the following Equation 1:

[Equation 1]

In Equation 1, ΔHm is the calorific value of the melting temperature peak measured by differential scanning calorimetry (DSC), ΔHc is the caloric value of the crystallization temperature peak measured by DSC, H100% is measured by DSC, PLA is 100 % It is the calorific value when crystallized.

In addition, in the present specification, "shrinkage rate of composite fiber" refers to the degree of shrinkage when dried in a drying oven at 100° C. for 10 minutes, and can be calculated according to the following Equation 2:

[Equation 2]

The composite fiber according to an embodiment of the present invention includes a core and a sheath.

The core may include polylactic acid (PLA) resin. For example, the core may include only PLA resin, and may not include any resin other than PLA resin (hereinafter referred to as 'other resin').

The PLA resin has a melt index (MFR: measured temperature 230°C, load 2.16 kg) measured according to ASTM D1238 of 2 to 30 g/10 min (eg, 5 to 25 g/10 min), and a melting temperature (Tm) of 160 It may be ~180°C.

In addition, the content of D-isomer (ie, poly-D-lactide) in the PLA resin may be less than 2% by weight, for example, less than 1% by weight. In the PLA resin, if the content of D-isomer is 2% by weight or more, the crystallinity of the raw material itself (ie, PLA resin itself) is relatively low, which is not suitable for the spunbond manufacturing process.

The other resin may include polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polyhydroxyalkanoate (PHA), or a combination thereof.

The weight ratio of the core and the sheath may be 50 to 90:10 to 50 (hereinafter referred to as 'Feature 1').

In addition, the content of the other resin in the sheath may be 10 to 50 parts by weight based on 100 parts by weight of the PLA resin (hereinafter referred to as 'Feature 2'). If the content of the other resin in the sheath is less than 10 parts by weight based on 100 parts by weight of the PLA resin, the other resin does not serve as a nucleating agent, so the crystallinity of the composite fiber may not be improved and the shrinkage rate may not be lowered, and 50 parts by weight If it is exceeded, the elongation of the composite fiber may be lowered.

By having the above features 1 and 2, the composite fiber can have high crystallinity and low shrinkage as well as 100% biodegradability.

The crystallinity of the composite fiber may be 30% or more. For example, the crystallinity of the composite fiber may be 30 to 55%. When the crystallinity of the composite fiber is less than 30%, a phenomenon in which the web is rolled on a roll or shrinkage of the nonwoven product may occur when the nonwoven web is formed. This can be a problem when processing tea.

In addition, the shrinkage rate of the composite fiber may be 20% or less. When the shrinkage rate of the composite fiber exceeds 20%, there may be a problem in the process of shrinking the nonwoven fabric during the manufacturing process of the nonwoven fabric.

1 is a cross-sectional view of a composite fiber 10 according to an embodiment of the present invention.

The composite fiber 10 according to an embodiment of the present invention includes a core 11 and a sheath 12 .

The core 11 comprises PLA resin, and the sheath 12 comprises a blend of PLA resin and other resins.

Another aspect of the present invention provides a nonwoven fabric including the composite fiber.

The nonwoven fabric may be a spunbond nonwoven fabric.

Hereinafter, the manufacturing method of the spunbond nonwoven fabric will be described in detail.

First, the resin for forming the core forming the core region of the composite fiber and the resin for forming the sheath forming the sheath region are separately melted with an extruder or the like, and a spinneret having a composite spinning nozzle configured to form and discharge a desired fiber structure Each melt is ejected from the to release the composite long fibers.

Thereafter, the discharged long fibers are cooled by cooling air, and tension is applied with the stretching air to have a predetermined fineness, and are collected as they are on a collection belt and deposited to a predetermined thickness.

Thereafter, post-processing is performed by a method using means such as a needle punch, water jet, ultrasonic wave, etc. as an entangling treatment, embossing using a heating embossing roll, or heat-sealing by high-temperature ventilation.

Hereinafter, the present invention will be described in more detail through examples. These examples are for explaining the present invention in more detail, and the scope of the present invention is not limited to these examples.

Example 1: Preparation of composite fibers

As a resin for forming the core, PLA resin having a melting point of 175° C. and a melt index of 10 g/10 min was used. In addition, as a resin for forming a sheath, 100 parts by weight of PLA resin having a melting point of 175 ° C and a melt index of 10 g/10 min and 10 parts by weight of PBAT having a melting point of 124 ° C and a viscosity of 1,450 poise (500 sec ^-1 , 230 ° C) are used. did The temperature of the extruder for melting the resin for forming the core and the resin for forming the sheath was 230°C, the molten resins were transferred to the core by the distribution plate in the composite spinning nozzle, and the resin for forming the sheath was transferred to the core. , and was spun in the form of a composite cross-section through a nozzle to form a composite fiber. The spinning speed when manufacturing the composite fiber was 1900 mpm, and the weight ratio of core: sheath was 70:30.

Example 2: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 1, except that a blend of 100 parts by weight of PLA resin and 30 parts by weight of PBAT was used as the resin for forming the sheath.

Example 3: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 1, except that a blend of 100 parts by weight of PLA resin and 50 parts by weight of PBAT was used as the resin for forming the sheath.

Example 4: Preparation of composite fibers

Composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 10 parts by weight of PBS having a melting point of 115° C. and a viscosity of 800 poise (500 sec ^-1 , 230° C.) were used as the resin for forming the sheath. was prepared.

Example 5: Preparation of composite fibers

Composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 30 parts by weight of PBS having a melting point of 115° C. and a viscosity of 800 poise (500 sec ^-1 , 230° C.) were used as the resin for forming the sheath. was prepared.

Example 6: Preparation of composite fibers

Composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 50 parts by weight of PBS having a melting point of 115° C. and a viscosity of 800 poise (500 sec ^-1 , 230° C.) were used as the resin for forming the sheath. was prepared.

Example 7: Preparation of composite fibers

The composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 10 parts by weight of PHA having a melting point of 160° C. and a viscosity of 540 poise (500 sec ⁻¹ , 210° C.) were used as the resin for forming the sheath. was prepared.

Example 8: Preparation of composite fibers

The composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 30 parts by weight of PHA having a melting point of 160° C. and a viscosity of 540 poise (500 sec ^-1 , 210° C.) were used as the resin for forming the sheath. was prepared.

Example 9: Preparation of composite fibers

Composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 50 parts by weight of PHA having a melting point of 160° C. and a viscosity of 540 poise (500 sec ^-1 , 210° C.) were used as the resin for forming the sheath. was prepared.

Example 10: Preparation of composite fibers

As a resin for forming a sheath, 100 parts by weight of PLA resin, 10 parts by weight of PBAT, 10 parts by weight of PBS having a melting point of 115° C. and a viscosity of 800 poise (500 sec ^-1 , 230° C.) and a melting point of 160° C. and a viscosity of 540 poise (500 sec ^-1 , 210° C.), a composite fiber was prepared in the same manner as in Example 1, except that a blend of 10 parts by weight of PHA was used.

Example 11: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 2, except that the weight ratio of core: sheath was changed to 50:50.

Example 12: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 2, except that the weight ratio of core: sheath was changed to 90:10.

Comparative Example 1: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 1, except that a blend of 100 parts by weight of PLA resin and 5 parts by weight of PBAT was used as the resin for forming the sheath.

Comparative Example 2: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 1, except that a blend of 100 parts by weight of PLA resin and 55 parts by weight of PBAT was used as the resin for forming the sheath.

Comparative Example 3: Preparation of composite fibers

The composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 5 parts by weight of PBS having a melting point of 115° C. and a viscosity of 800 poise (500 sec ^-1 , 230° C.) were used as the resin for forming the sheath. was prepared.

Comparative Example 4: Preparation of composite fibers

Composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 55 parts by weight of PBS having a melting point of 115° C. and a viscosity of 800 poise (500 sec ^-1 , 230° C.) were used as the resin for forming the sheath. was prepared.

Comparative Example 5: Preparation of composite fibers

Composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 5 parts by weight of PHA having a melting point of 160° C. and a viscosity of 540 poise (500 sec ^-1 , 210° C.) were used as the resin for forming the sheath. was prepared.

Comparative Example 6: Preparation of composite fibers

The composite fiber in the same manner as in Example 1, except that 100 parts by weight of PLA resin and 55 parts by weight of PHA having a melting point of 160° C. and a viscosity of 540 poise (500 sec ^-1 , 210° C.) were used as the resin for forming the sheath. was prepared.

Comparative Example 7: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 2, except that the weight ratio of core: sheath was changed to 45:55.

Comparative Example 8: Preparation of composite fibers

A composite fiber was prepared in the same manner as in Example 2, except that the weight ratio of core: sheath was changed to 95:5.

evaluation example

The crystallization temperature (ΔHc), crystallinity, and shrinkage of the composite fibers prepared in Examples 1 to 12 and Comparative Examples 1 to 8 were measured, and the results are shown in Table 1 below. Here, the crystallization temperature (ΔHc), the calorific value of the melting temperature peak (ΔHm), and the calorific value when PLA is 100% crystallized (H _100% ) were measured using a differential scanning calorimeter (DSC), and the degree of crystallinity was calculated according to Equation 1, and the shrinkage rate was calculated according to Equation 2 above.

ΔHc Crystallinity (%) Shrinkage (%) Example 1 15 45 5 Example 2 20 40 8 Example 3 23 38 9 Example 4 25 35 11 Example 5 26 33 11 Example 6 26 32 12 Example 7 28 30 15 Example 8 29 30 20 Example 9 29 30 20 Example 10 28 31 14 Example 11 22 38 10 Example 12 24 39 10 Comparative Example 1 33 23 27 Comparative Example 2 34 24 29 Comparative Example 3 34 22 33 Comparative Example 4 34 21 33 Comparative Example 5 35 20 37 Comparative Example 6 36 18 40 Comparative Example 7 37 19 35 Comparative Example 8 35 21 39

Referring to Table 1, it was found that the degree of crystallinity prepared in Examples 1 to 12 was as high as 30% or more, and the shrinkage rate was as low as 20% or less. However, the composite fibers prepared in Comparative Examples 1 to 8 had a low crystallinity of 24% or less and a high shrinkage rate of 27% or more.

Although the present invention has been described with reference to the drawings and embodiments, these are merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

10: composite fiber 11: core
12: sheath

Claims (8)

As a composite fiber, the composite fiber,
a core comprising only polylactic acid (PLA) resin and no resin other than PLA resin; and
a sheath comprising a combination of PLA resin and other resins;
The other resin includes polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polyhydroxyalkanoate (PHA), or a combination thereof,
The weight ratio of the core and the sheath is 50-90:10-50,
The content of the other resin in the sheath is 10 to 50 parts by weight based on 100 parts by weight of the PLA resin,
A composite fiber having a crystallinity of 30% or more and a shrinkage ratio of 20% or less of the composite fiber. delete delete delete delete delete A nonwoven fabric comprising the composite fiber according to claim 1 . 8. The method of claim 7,
The nonwoven fabric is a spunbond nonwoven fabric.

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