KR20230102577A - Recycle polyester fiber using polyester waste and manufactuing method thereof - Google Patents

Abstract

The present invention relates to regenerated polyester fibers using polyester waste and a method for producing the same. In the method for producing regenerated polyester fibers according to an embodiment of the present invention, high-quality regenerated polyester fibers are produced by adjusting the pressure of an extruder. can do.

Description

Recycled polyester fiber using polyester waste and its manufacturing method {RECYCLE POLYESTER FIBER USING POLYESTER WASTE AND MANUFACTUING METHOD THEREOF}

The present invention relates to regenerated polyester fibers using polyester waste and a method for producing the same, and more particularly, to high-quality regenerated polyester fibers produced by controlling the pressure of an extruder and a method for producing the same.

Polyester has excellent mechanical properties, heat resistance, moldability, and chemical resistance, and thus is used in a wide range of applications in the fields of fibers, films, and bottle molded products. Although these polyester products are discarded after use, incineration causes problems such as generation of harmful gases during combustion and damage (corrosion) of the incinerator due to high heat. In addition, in the case of disposal without incineration, there is a problem in that it does not decompose and remains permanently in the soil or water and acts as a pollutant that causes acidification of the soil.

Conventionally, as a method of recycling waste polyester, a method of producing oligomers by glycolysis of waste polyester through depolymerization using ethylene glycol has been introduced in US Patent US 4,078,143 and UK Patent 610,136, and the resulting oligomer is polymerized. German patent 1,151,939 and European patent 174,062 have introduced methods to do this, but these technologies lack the technology to control the diethylene glycol component generated in the process of glycolysis of waste polyester and the technology to suppress discoloration of oligomers. There is a disadvantage that high quality textile products cannot be manufactured.

U.S. Patent No. 5,266,601 discloses polybutylene by polymerizing 1,4-butylene-based polyester oligomer obtained through transesterification with 1,4-butanediol after preparing an oligomer by glycolysis of waste polyester using ethylene glycol. Although a method for producing terephthalate has been introduced, there is a disadvantage in that it can be applied only to colored injection moldings because there is no technology for suppressing discoloration occurring in the oligomer manufacturing process.

U.S. Patent No. 7,297,721 introduces a method of depolymerizing waste polyester using terephthalic acid, isophthalic acid and ethylene glycol, which are pure raw materials, to polymerize recycled polyester. The depolymerization process has a high temperature of 240° C. to 270° C., and thus energy consumption is high.

As described above, the method of recycling waste polyester through depolymerization has excellent physical properties of recycled polyester, but the cost of recycling polyester is high and it takes a long time between processes, so it is difficult to process all of the increasing amount of waste polyester. there is

As a method of quickly recycling waste polyester, a material recycling method in which waste polyester is simply extruded to manufacture polyester chips and recycled is being commercialized.

US Patent US 4,078,143 British Patent 610,136 US Patent US 5,266,601 US Patent US 7,297,721

The present invention is to provide a high-quality recycled polyester fiber produced by controlling the pressure of an extruder and a method for producing the same.

The present invention comprises the steps of injecting polyester waste into an extruder; Adjusting the pressure generated according to the input of the polyester waste; and spinning the molten waste polyester resin through the extruder.

A step of drying the polyester waste prior to the inputting step may be included.

The waste polyester resin melted in the spinning step may be filtered through a filter and then spun.

cooling and winding the undrawn yarn spun and discharged after the spinning step; drawing the wound yarn; and crimping the drawn yarn.

The polyester waste may be obtained by grinding polyester by-products generated during the manufacture of polyester products or wastes discarded after use of polyester products.

The polyester waste may be in the form of flakes and have a diameter of 0.1 to 40 mm of a circle circumscribing the flakes.

The pressure of the extruder is controlled by a screw compression ratio defined by Equation 1 below, and the compression ratio may be 2 to 5.

[Equation 1]

Compression ratio=H ₁ /H ₂

In the above formula, H ₁ is the depth of the first screw head, and H ₂ is the depth of the last screw head.

The pressure of the extruder is controlled by LD defined by Equation 2 below, and the LD may be 20 to 40.

[Equation 2]

LD=L/D

In the above formula, L is the length of the screw and D is the diameter of the screw.

The extruder is divided into a supply part, a melting part, and a discharge part, and the supply part may be maintained at a temperature of 250 to 260 ° C, the melting part at a temperature of 265 to 270 ° C, and the discharge part at a temperature of 270 to 290 ° C.

The discharge pressure of the extruder may be 40 to 60 bar.

Another embodiment of the present invention provides a recycled polyester fiber produced by the above method.

According to one embodiment of the present invention, high-quality recycled polyester fibers can be produced by controlling the pressure in the extruder.

As the pressure of the extruder is kept constant, penetration of moisture can be prevented, and heat can be prevented from being overheated in a specific area. Accordingly, it is possible to prevent the intrinsic viscosity of waste polyester from falling. Accordingly, fibers excellent in bulkiness, cushioning, strength, elongation, etc. can be manufactured.

According to one embodiment of the present invention, fibers can be produced by directly spinning waste polyester flakes instead of recycled chips. It can also use waste collected from a variety of sources.

1 is a schematic diagram schematically illustrating a manufacturing process of regenerated polyester fibers according to an embodiment of the present invention.
2 is a cross-sectional view schematically showing an extruder according to an embodiment of the present invention.
3 is a cross-sectional view schematically showing a screw mountain according to an embodiment of the present invention.
4 is a view schematically showing a part of a screw according to an embodiment of the present invention.

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

In addition, the same or corresponding components in the drawings are assigned the same or similar reference numerals, and redundant description thereof will be omitted. For convenience of explanation, the size and shape of each component member shown may be exaggerated or reduced. .

Terms used in this application are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise" or "have" are intended to designate that there is a feature, step, operation, component, part, or combination thereof described in the specification, but one or more other features or steps However, it should be understood that it does not preclude the possibility of existence or addition of operations, components, parts, or combinations thereof.

In addition, unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, it should not be interpreted in an ideal or excessively formal meaning. don't

A method for producing recycled polyester fibers according to an embodiment of the present invention includes the steps of injecting polyester waste into an extruder; Adjusting the pressure generated according to the input of the polyester waste; and spinning the molten waste polyester resin through the extruder.

Recycled polyester fibers according to an embodiment of the present invention are manufactured using various polyester wastes as raw materials, and may include staple fibers or filaments.

1 is a schematic diagram schematically showing a manufacturing process of regenerated polyester fibers according to an embodiment of the present invention, FIG. 2 is a cross-sectional view schematically showing an extruder according to an embodiment of the present invention, and FIG. A cross-sectional view schematically showing a screw ridge according to an embodiment, and FIG. 4 is a view schematically showing a part of a screw according to an embodiment of the present invention.

As shown in FIG. 1, polyester waste is put into an extruder 110 to be melted, filtered through a filter 120, and the melted waste polyester resin is transported to a spinning pack 130 and discharged, followed by cooling. And, after drawing and drawing through rollers 1 and 3, crimping, drying and cutting, fibers can be produced.

Hereinafter, a method for producing regenerated polyester fibers will be described in detail.

First, as shown in FIG. 2, polyester waste (C) may be introduced into the extruder through the hopper 111 of the extruder 110.

The polyester waste introduced into the extruder 110 is gradually melted along the screw 112 to become a waste polyester resin, and is discharged through the nozzle of the spinning pack 130.

According to one embodiment of the present invention, the polyester waste (C) may be pulverized polyester by-products generated during the manufacture of polyester products or waste discarded after use of polyester products.

The polyester product may be a polyester fiber, a polyester film, a polyester bottle, a PET bottle, etc. manufactured using a virgin raw material, and in the present invention, these products can be manufactured. The by-products generated can be collected and used.

According to one embodiment of the present invention, the polyester waste (C) may use flakes having a size of 0.1 to 40∮. The unit ∮ (pi) means the diameter of a circle circumscribing an irregular particle (polyester waste). That is, the diameter of the circle circumscribing the polyester waste (C) may be 0.1 to 40 mm.

According to one embodiment of the present invention, a step of drying the polyester waste may be performed before introducing the polyester waste into the extruder.

The polyester waste is not limited thereto, but, for example, off-grade chips, R chips, PET bottle pulverized material, various popcorn, sheet pulverized, shrimp crackers, preforms, or lumps may be used.

The off-grade chip refers to a chip that has not been used because it does not meet the standard in the polymerization process of making a virgin chip. The PET bottle pulverized material may be obtained by collecting, sorting, washing, and pulverizing discarded PET bottles.

The sheet pulverized product (sheet) can be obtained by collecting and pulverizing them as a part that is not a product during manufacture of a thick film or electronic component case.

R-chips, also called pellets or juping chips, are made by crushing films or PET bottles and then coarsely pulling them out in a large extruder to form chips the size of rice grains.

Shrimp Cracker is made similar to the shape of Shrimp Cracker by compressing film powder, etc., and Lump is the first spinning of virgin fibers, bottles, and films.

Textile popcorn is made by collecting textile factory residues and filaments (spinning, unstretched, tow), etc., and rubbing them together with heat and moisture, while film popcorn is made by cutting thin films to form popcorn. it did

In general, in order to manufacture recycled fibers, polyester waste is collected, foreign substances are removed to make recycled chips, and recycled fibers are manufactured using the recycled chips. Wastes that are not processed into chips, that is, flakes having various sizes, are difficult to melt uniformly in an extruder due to non-uniformity in shape and size, and it is difficult to maintain a constant discharge pressure. In addition, it is difficult to manufacture fibers due to the high content of foreign matter and moisture, and even if the fibers are manufactured, the quality of the fibers is inevitably low.

However, according to one embodiment of the present invention, wastes collected from various sources can be used, and fibers can be produced by directly spinning waste polyester flakes rather than recycled chips.

According to one embodiment of the present invention, it is possible to adjust the pressure generated according to the input of the polyester waste. In other words, it is possible to solve pressure non-uniformity in the extruder caused by the input of polyester waste of various sizes. High-quality recycled polyester fibers can be produced by constantly adjusting the pressure of the extruder. In addition, as the pressure of the extruder is maintained constant, moisture permeation can be prevented, and heat can be prevented from being overheated in a specific area. Accordingly, it is possible to prevent the intrinsic viscosity (IV, Intrinsic Viscosity) of waste polyester from falling.

In general, when polyester waste is used, the intrinsic viscosity is lowered and the quality of the fiber is lowered. Causes of the decrease in intrinsic viscosity include hydrolysis, thermal decomposition and oxidative decomposition. Hydrolysis is caused by moisture, and the main cause is moisture in polyester waste. Thermal decomposition is caused by overheating, and the main cause is the temperature rise of cylinders and spin beams. Oxidative decomposition is caused by oxygen, and the inflow of air during melting is the main cause.

When the pressure in the extruder is constantly adjusted as in one embodiment of the present invention, penetration of moisture and oxygen and an increase in temperature in some sections can be prevented. Accordingly, fibers excellent in bulkiness, cushioning, strength, elongation, etc. can be manufactured.

Referring to FIG. 2 , the screw in the extruder 110 may be divided into a supply unit 112A, a melting unit 112B, and a discharge unit 112C. The supply unit 112A is a zone for receiving waste and may maintain a temperature of 250 to 260°C. The melting section 112B is a region where melting begins and may maintain a temperature of 265 to 270°C. The discharge part 112C is a zone where waste becomes molten resin and can maintain a temperature of 270 to 290 °C. In addition, the pressure of the extruder discharge unit may be 40 to 60 bar.

According to one embodiment of the present invention, the step of adjusting the pressure of the extruder may be performed through a compression ratio of a screw provided inside the extruder.

The compression ratio of the screw may be defined by Equation 1 below.

[Equation 1]

Compression ratio=H ₁ /H ₂

In the above formula, H ₁ is the depth of the first screw head, and H ₂ is the depth of the last screw head.

Referring to FIGS. 2 and 3 , according to one embodiment of the present invention, the diameter of the screw rotation shaft may increase from the supply part 112A to the discharge part 112C. Accordingly, the depth of the acid (screw acid) formed in the screw may decrease from the supply part 112A to the discharge part 112C.

The supply unit 112A is a region containing polyester waste, and the depth of the screw mountain should be deepened as waste with a large size is used. That is, when the particles of the waste used are small, the compression ratio is low, and when the particles of the waste are large, the compression ratio must be increased to maintain a uniform discharge amount.

According to one embodiment of the present invention, the depth (H ₁ ) of the first screw head (113a) of the supply unit (112A) and the depth (H ₂ ) of the last screw head (113b) of the discharge unit (112C) defined as the ratio The compression ratio (H ₁ /H ₂ ) may be 2 to 5. That is, since the depth of the first screw head 113a of the supply part is formed deeper than the depth of the last screw head 113b of the discharge part, the input waste can be well accommodated. If the compression ratio is out of the above range, the melting of the polyester waste may proceed non-uniformly.

In general, when spinning using virgin raw materials or using waste, the depth of screw heads is all designed the same. However, according to one embodiment of the present invention, the depth of the screw head can be designed in various ways according to the type of waste to be used, and accordingly, the pressure of the extruder can be kept constant.

Also, according to one embodiment of the present invention, the pressure of the extruder may be adjusted by the LD of the screw defined by Equation 2 below.

[Equation 2]

LD=L/D

In the above formula, L is the length of the screw and D is the diameter of the screw.

Referring to FIG. 4 , the diameter (D) of the screw may be measured including the axis of rotation of the screw and the screw head.

According to one embodiment of the present invention, the LD of the screw may be 20 to 40. Specifically, it may be 25 to 35, and more specifically, it may be 28 to 32. If the LD of the screw is out of the above range, the melting of the polyester waste may proceed non-uniformly.

The molten waste polyester resin may pass through the discharge unit 112C and be filtered through the filter 120.

The filtered waste polyester resin may be sprayed through the spinning pack 130 .

The spinning pack 130 of the present invention may include a filtering layer, a pressure plate, a dispersion plate, and a nozzle. Foreign substances are removed by the filtration layer, and the pressure of the spinning pack is increased and the pressure is evenly spun to make resins for each nozzle to make fibers having a uniform thickness.

According to one embodiment of the present invention, the spinning speed may be 950 to 1100 mpm.

The fiber spun through the nozzle may pass through a cooling tube and be rapidly cooled and solidified. The temperature of the cooling tub may be set to about 21°C in summer and about 19°C in winter.

Next, the cooled fibers may be wound and drawn through the winder (3). At this time, the thickness (denier) of the fiber can be adjusted by adjusting the discharge amount of the spinning machine and the rotational speed of the winder.

Specifically, the spun yarn may be wound, placed in a can, and sub-tow yarns may be stretched at an appropriate ratio, for example, 3 to 4.5 times to impart strength and elongation. The stretching temperature may be 75 to 85°C.

The drawn yarns can be carded and crimped to impart elasticity and touch. After the crimping operation, drying and heat treatment setting may be performed.

Afterwards, it can be cut and packaged to make final products.

Hereinafter, the present invention will be described in more detail through examples, and the scope of the present invention is not limited by the examples.

[Example]

Examples 1 to 3

Collect off-grade chips, R chips, crushed PET bottles, various popcorn, crushed sheets, shrimp crackers, preforms, and lumps, and dry them in a screw dryer for 2 hours so that the moisture content is 200 to 500 ppm did

Melt spinning was performed using an extruder equipped with a screw having an LD of 25 to 35 and a compression ratio of 3 to 5. The temperature of the cooling tube was set at 20 ° C, and the drawing was performed by adjusting the discharge amount of the spinning machine and the rotational speed of the roller. The drawing temperature and the drawing ratio of sub-tow yarns spun and contained in a can are shown in Table 1 below. The drawn yarns were crimped, and drying and heat treatment setting processes were performed.

Comparative Example 1 and Comparative Example 3

In Comparative Examples 1 to 3, fibers were manufactured using PET chips (Virgin PET) as a raw material (Toray Corporation).

division Spinning speed (mpm) cross section Stretching temperature (℃) stretch ratio Fiber length (mm) Example 1 1.4D 1000 circle 79 3.6 51 Example 2 2D 1000 circle 82 3.6 51 Example 3 3D 1000 circle 82 3.6 51 Comparative Example 1 1.4D 1300 circle 85 3.4 38 Comparative Example 2 2D 1200 circle 82 3.5 51 Comparative Example 3 3D 1100 circle 85 3.7 64

[evaluation]

The fineness, strength, and elongation of the fibers obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were compared. This is shown in Table 2 below.

division fineness (denier) Intensity (g/de) Shinto Example 1 1.4D 1.5 4.2 55 Example 2 2D 2.1 4 60 Example 3 3D 3.2 3.9 68 Comparative Example 1 1.4D 1.5 4.6 54 Comparative Example 2 2D 1.8 4.7 58 Comparative Example 3 3D 3.1 4.8 62

Referring to Table 2, in the case of Examples 1 to 3 using waste raw materials, it can be confirmed that fine fibers of 1.5 D can be produced, and it can be confirmed that they have strength and elongation similar to those of Comparative Examples 1 to 3. .

The above description is merely an example of the technical idea of the present embodiment, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of the present embodiment, but to explain, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of this embodiment should be interpreted according to the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of rights of this embodiment.

110: extruder 120: filter
130: radiation pack
112: screw 113, 113a, 133b: screw mount

Claims (11)

Injecting polyester waste into an extruder;
Adjusting the pressure generated according to the input of the polyester waste; and
spinning the molten waste polyester resin through the extruder;
Method for producing recycled polyester fibers comprising a.
According to claim 1,
Method for producing recycled polyester fibers comprising the step of drying polyester waste prior to the input step.
According to claim 1,
The waste polyester resin melted in the spinning step is filtered through a filter and then spun.
According to claim 1,
cooling and winding the undrawn yarn spun and discharged after the spinning step;
drawing the wound yarn; and
A method for producing recycled polyester fibers comprising crimping the drawn yarn.
According to claim 1,
The polyester waste is a method for producing recycled polyester fibers obtained by grinding polyester by-products generated during the manufacture of polyester products or wastes discarded after use of polyester products.
According to claim 1,
The polyester waste is in the form of flakes, and the diameter of the circle circumscribing the flakes is 0.1 to 40 mm.
According to claim 1,
The pressure of the extruder is controlled by a screw compression ratio defined by Equation 1 below, and the compression ratio is 2 to 5. Method for producing recycled polyester fiber.
[Equation 1]
Compression ratio=H ₁ /H ₂
In the above formula, H ₁ is the depth of the first screw head, and H ₂ is the depth of the last screw head.
According to claim 1,
The pressure of the extruder is controlled by LD defined by Equation 2 below, wherein the LD is 20 to 40.
[Equation 2]
LD=L/D
In the above formula, L is the length of the screw and D is the diameter of the screw.
According to claim 1,
The extruder is divided into a supply part, a melting part, and a discharge part, and the supply part is maintained at a temperature of 250 to 260 ° C, the melting part is at a temperature of 265 to 270 ° C, and the discharge part is maintained at a temperature of 270 to 290 ° C. Manufacturing method of.
According to claim 1,
The discharge pressure of the extruder is a method for producing recycled polyester fibers of 40 to 60 bar.
Recycled polyester fiber produced by the method of any one of claims 1 to 10.

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