KR20220117934A - Manufacturing method of monofilament yarn using recycled PET - Google Patents

Abstract

The present invention relates to a method for manufacturing monofilament yarn for shoes, shoemaking, or chairs adopting, as a material, recycled PET using waste PET bottles, which comprises: a drying process of performing washing and drying after compressing collected transparent waste PET bottles and cutting the compressed bottles in a flake shape; a crystallization process for preventing hydrolysis due to moisture; a recycled PET chip molding process; and a process of manufacturing monofilament yarn by adding stearic acid metal salt to the recycled PET chips and performing melt-spinning. The present invention is very advantageous in manufacturing higher quality PET monofilament yarn for shoes, shoemaking, or chairs without deterioration of the physical properties of PET using the recycled PET obtained from waste PET bottles as a raw material without a decrease in intrinsic viscosity.

Description

Manufacturing method of monofilament yarn using recycled PET

The present invention relates to a method for manufacturing a monofilament yarn using recycled PET, and more particularly, to a method for manufacturing a monofilament yarn for shoes, shoes, or chairs using recycled PET manufactured from waste PET bottles.

In general, monofilament yarns made of polyester (PET), nylon, and polyether ester (TPEE) are mainly used for the outer skin of shoes such as sneakers and shoes or fabrics for chairs, but recently, shoes. The demand for recycled monofilaments suitable for fabrics such as shoes and shoes is increasing as it is required to use recycled raw materials for the purpose of marketing the eco-friendly image of shoe or chair manufacturing brands.

Polyethylene terephthalate (PET) has excellent physical and chemical properties and is used in various applications such as fibers, films, tire cords, and beverage containers. If it is not treated, it remains as a pollutant that causes environmental pollution, so research and development related to the recycling of used PET bottles (waste PET bottles) are being made steadily.

PET monofilament yarn suitable for the outer fabric of shoes such as sports shoes and shoes is suitable to use PET with an intrinsic viscosity (I.V) of 0.80, but PET raw materials regenerated from waste PET bottles have an I.V of 0.68 ~ It drops to 0.75 level, it is not uniform and there is a lot of variation, and during the molding operation of recycled PET, the molecular weight decreases due to hydrolysis, etc.

In relation to the recycling of waste PET bottles, for example, in the prior art, in Patent Document 1, PET bottles are separated by color and crushed to a predetermined size to form PET chips; A washing step that removes foreign substances, label bonds, and chemicals using hot water and a drying step, a drying step of removing moisture and foreign substances remaining on the PET chip washed in the washing step, a sorting step, a crushing step, a washing step, and a drying step Disclosed is a plastic bottle regeneration method comprising a dust collecting unit for collecting and removing contaminants generated in , Patent Document 2 discloses an input step of putting in a compressed plastic bottle, and dismantling the compressed and injected plastic bottle in the input step, and attached to the PET bottle A screening step of separating foreign substances and sorting by color of the PET bottle at the same time, a crushing step in which PET chips are formed by pulverizing to a predetermined size after the selection is completed in the screening step, and the crushing PET chips crushed in the crushing step with cold water A washing step of removing foreign substances, label bonds, and chemicals using hot water, a drying step of removing moisture and foreign substances remaining on the PET chip washed in the washing step, the screening step, the grinding step, the washing step, and the drying step Disclosed is a PET bottle regeneration method characterized in that it consists of a dust collecting unit that collects and removes contaminants generated in the step, but the prior art is merely a technology for selecting waste PET bottles, and the intrinsic viscosity of the recycled PET raw material There are no implications for improving

And in Patent Document 3, carbonylbiscaprolactam (CBC), 1,4-phenylenebisoxazoline (p-BOX) and 1,3-phenylenebis on a polyester chip having an intrinsic viscosity of 0.8 to 1.10 dl/g Disclosed is a method for producing high-viscosity and high-strength industrial polyester fiber, characterized in that 0.25 to 1.00% by weight of one compound selected from oxazoline (m-BOX) is added based on the total weight of the spinning resin in the melt spinning process are doing

The inventor of the present invention developed a method for manufacturing a PET monofilament yarn suitable as a fabric for the outer skin of shoes, such as sports shoes and shoes, using PET raw materials regenerated from waste PET bottles, and completed the present invention.

US 10-0578766 B1 US 10-0895529 B1 US 10-1429686 B1

The problem to be solved in the present invention relates to the provision of a method for manufacturing a monofilament yarn using recycled PET, and more specifically, a recycled PET chip is manufactured using a waste PET bottle, and the material is used for footwear, shoemaking or An object of the present invention is to provide a method for manufacturing a monofilament yarn for a chair.

As a means of solving the problem according to the present invention, a method for manufacturing monofilament yarn using recycled PET is a drying process in which the collected transparent waste PET bottles are compressed, cut into flakes, washed and dried, and hydrolysis by moisture. It consists of a crystallization and regenerated PET chip forming process for prevention, a process of mixing a metal stearic acid salt with a regenerated PET chip, melting and spinning in a spinning device, and extrusion molding to produce a monofilament yarn

One embodiment of the method for manufacturing a monofilament yarn using recycled PET according to the present invention is a). A first step of screening and pulverizing the collected waste PET bottles into flakes together with compression, washing with hot water, and then screening to screen the pulverized transparent waste PET flakes, b). A second step of dehumidifying and drying the pulverized transparent waste PET, c). A third step of crystallizing the dried pulverized transparent waste PET at a constant temperature for a certain time, d). A fourth step of heating and melting the crystallized PET pulverized product at a certain temperature, extruding the molten PET while filtering, molding it into a recycled PET chip, and cooling and drying it to room temperature and e). A fifth step of manufacturing a PET monofilament yarn by blending a metal stearic acid salt with the regenerated PET chip and melt-spinning in a spinning device under melting temperature conditions.

Another embodiment of the method for manufacturing a monofilament yarn using recycled PET according to the present invention is a). The first process of sorting the pulverized transparent waste PET flakes by cutting and pulverizing the collected waste PET bottles into flakes with a size of 5 to 10 mm together with compression, washing by pouring hot water at 70 to 80 ° C, and screening , b). A second step of dehumidifying and drying the waste transparent PET pulverized product to a residual moisture content of 0.1 wt% or less, c). A third step of crystallizing the dried transparent waste PET pulverized product at 140 to 165° C. for a certain period of time, d). The fourth process of melting the crystallized PET pulverized product by heating it to 260 ~ 270℃, extruding the molten PET while filtering it with a filter of 100 ~ 250 mesh, molding it into a recycled PET chip, and cooling and drying it to room temperature and e). 5th process of manufacturing PET monofilament yarn by mixing metal stearic acid salt with regenerated PET chip at a concentration of 0,01 to 0.03 wt%, melt-spinning in a spinning device under melting temperature conditions, and then cooling, stretching and heat setting consists of including

And as another problem solving means of the present invention, the monofilament yarn using recycled PET is made of a PET monofilament yarn manufactured by the manufacturing method of the first to fifth steps described above, and in particular, for shoes, shoes, or chairs. It is made of PET monofilament yarn,

The manufacturing method of filament yarn using recycled PET of the present invention has the effect of producing monofilament yarn for shoes, shoes, or chairs while smoothly supplying recycled PET raw materials to the extruder without reducing intrinsic viscosity. It has a very advantageous advantage in that it can prevent deterioration and produce higher-quality PET monofilament yarns for shoes, shoes, or chairs.

Hereinafter, the present invention will be described in more detail in order to carry out the present invention, but the present invention is not limited by the contents described below.

A method for manufacturing a monofilament yarn using recycled PET according to the present invention is a). A first step of screening and pulverizing the collected waste PET bottles into flakes together with compression, washing with hot water, and then screening to screen the pulverized transparent waste PET flakes, b). A second step of dehumidifying and drying the pulverized transparent waste PET, c). A third step of crystallizing the dried pulverized transparent waste PET at a constant temperature for a certain time, d). A fourth step of heating and melting the crystallized PET pulverized product to a certain temperature, extruding the molten PET while filtering it, forming a regenerated PET chip, and cooling and drying to room temperature and e). A fifth process of manufacturing PET monofilament yarn by mixing metal stearic acid salt with recycled PET chips, melt-spinning in a spinning device under melting temperature conditions, and then cooling, stretching and heat setting.

In the first process according to the present invention, transparent waste PET bottles are selected from PET wastes, contaminants, labels, etc. are removed to separate only the selected transparent waste PET bottles, and then compressed to increase crushing efficiency, then 5 to 10 mm After cutting and pulverizing into waste PET flakes of the size, the PET flakes are put into a washing tank equipped with a heating means and washed with hot water at 70 ~ 80℃, and then foreign substances such as small and heavy metals are separated by screen operation and only transparent PET flakes are produced. It is done by selecting

Although the selection of transparent waste PET bottles from the PET wastes can be done manually, using an optical sorter to separate colored waste PET bottles that are difficult to distinguish with the naked eye, and select only transparent waste PET bottles to obtain higher purity waste PET chips. It is preferable to manufacture

The second process according to the present invention is a process of removing moisture from the pulverized transparent waste PET in order to prevent a decrease in the degree of polymerization due to hydrolysis of PET and deterioration of the physical properties of PET. It consists of dehumidifying and drying so that the moisture content is 0.1% by weight or less.

In the third process according to the present invention, the dried transparent waste PET pulverized product is crystallized at a certain temperature for a certain time, and the crystallization process may have a different crystallization time depending on the input amount and the crystallization temperature of the pulverized transparent waste PET, but generally 140 ~ It consists of crystallization at 165°C for 1 to 2 hours.

In general, when PET is heated to a crystallization temperature, that is, 140 to 165° C., the molecular chains are aligned to form micrometer-level units and become opaque, and heat resistance is improved.

The third process is a crystallization facility widely employed in the technical field to which the present invention pertains. For example, a rotary type crystallization facility for crystallizing by flowing the contents while rotating a heating vessel or a high-speed stirrer mounted inside a heating hopper It crystallizes by employing equipment that crystallizes while flowing the contents into the furnace.

In the present invention, when a transparent waste PET pulverized product that has not been crystallized is molded into a chip as it is, problems such as fusion of the molded chip is not easy due to fusion in a molding machine. It consists of hiring

The fourth process according to the present invention is a process of forming regenerated PET chips while melt-extruding the crystallized PET pulverized product with an extruder. It is heated and melted.

The process of forming the regenerated PET chip is by heating and melting the crystallized PET pulverized product using an extruder, and extruding it while filtering with a 100 to 250 mesh filter to remove foreign substances from the molten liquid PET. It consists of cooling and drying to room temperature after molding into 1mm size recycled PET chips.

The fifth process according to the present invention is a process for producing PET monofilament yarn by melt-spinning recycled PET chips with a spinning device, and blending metal stearic acid salts with the recycled PET chips at a concentration of 0,01 to 0.03 wt%, It consists of manufacturing a PET monofilament yarn by melt spinning under a melting temperature condition.

The metal stearic acid salt is prepared in a monofilament yarn having a uniform viscosity by preventing a decrease in the intrinsic viscosity of PET and smooth spinning of the melt in the process of melting and spinning, and the metal stearic acid salt is calcium stearate or magnesium stearate.

The process of producing PET monofilament yarn by melt spinning in a spinning device in the fifth step is extrusion molding by melt spinning at 260 ~ 280 ℃, then cooling at 25 ~ 35 ℃ by water cooling, and then stretching and heat setting PET. It consists in producing monofilament yarn.

In the fifth process, the PET melt must be smoothly supplied to the screw of the spinning device to produce yarn with uniform properties. Therefore, the feed condition of the raw material is that the raw material input speed near the screw is twice the raw material input speed of the supply unit (hopper). It is preferable to supply raw materials as much as possible.

The above-described raw material input condition is that the structure of the raw material supply means has an inverted pyramid-shaped structure that narrows from the inlet (hopper) to the vicinity of the screw in order to increase the speed at which the raw material is fed in the vicinity of the screw of the spinning device, and the input port (hopper) ), it is possible to increase the feed rate near the screw to twice the hopper feed rate of the raw material while the hourly feed rate of the raw material is constant by making the area of the tip of the screw and the area adjacent to the screw in a ratio of 2:1.

The stretching and heat setting in the fifth step is after cooling by water cooling to 15 ~ 25 ℃, the primary stretching roller speed is 34 ~ 40 m / min, the secondary stretching roller speed is 155 ~ 180 m / min, the third stretching roller speed is set to 155 ~ 180m/min, respectively, and the 4th stretching roller speed is set to 150 ~ 175m/min lower than the 3rd and heat setting is performed, and the stretching ratio is the speed ratio of the 1st ~ 3rd stretching roller It is determined, and it is preferable to set the draw ratio to 4.2 to 5.0 times.

In addition, in the stretching step, water treatment stretching is carried out at 70 ~ 95 ℃ between the primary stretching roller and the secondary stretching roller, and between the secondary stretching roller and the third stretching roller, a dry heat treatment is performed at 130 ~ 190 ℃ by a secondary heat treatment. It consists of dry heat setting between the 3rd and 4th rollers at a level of 130 ~ 190°C with a 3rd heat treatment.

In addition, the PET monofilament yarn produced by the first to fifth processes according to the present invention has a breaking strength of 3.8 to 4.8 gf/denier, a breaking elongation of 40 to 60%, and a fabric for shoes, shoes, or chairs. It is made of PET monofilament yarn suitable for its use.

Claims (7)

a). The first process of sorting the pulverized transparent waste PET flakes by cutting and pulverizing the collected waste PET bottles into flakes together with compression, washing with hot water, and then screening;
b). A second process of dehumidifying and drying the transparent waste PET pulverized material;
c). A third process of crystallizing the dried transparent waste PET pulverized product at a certain temperature for a certain time,
d). The fourth process of heating and melting the crystallized PET pulverized product at a certain temperature, filtering the molten PET and extruding it to form a recycled PET chip, cooling and drying to room temperature, and
e). Recycled PET, characterized in that it comprises a fifth step of manufacturing PET monofilament yarn by mixing metal stearic acid salt with recycled PET chip, melt-spinning in a spinning device under melting temperature conditions, and then cooling, stretching and heat setting. Method for manufacturing monofilament yarn using The method for manufacturing monofilament yarn using recycled PET according to claim 1, wherein in the third step, the dried transparent waste PET pulverized product is crystallized at 140 to 165° C. for 1 to 2 hours. The method according to claim 2, In the fourth process, the crystallized PET pulverized product is melted by heating at a temperature of 260 ~ 270 °C, and the melt is extruded while filtering with a 100 ~ 250 mesh filter to form a regenerated PET chip having a size of 0.5 ~ 1 mm. A method for manufacturing a monofilament yarn using recycled PET, characterized in that it is cooled to room temperature and dried. The method according to claim 3, wherein the metal stearic acid salt in the fifth step is a mixture of calcium stearate or magnesium stearate in a concentration of 0.01 ~ 0.03wt%, the melting temperature condition is 270 ~ 280 ℃ regeneration, characterized in that the melt spinning Method for manufacturing monofilament yarn using PET. The method for manufacturing monofilament yarn using recycled PET according to claim 4, wherein the spinning device supplies the raw material so that the raw material input speed in the vicinity of the screw is twice the raw material input speed of the supply unit. A monofilament yarn using recycled PET, characterized in that it is manufactured by the manufacturing method according to any one of claims 1 to 5. The monofilament yarn using recycled PET according to claim 6, wherein the monofilament yarn using recycled PET is a PET monofilament yarn for fabrics for shoes, shoes, or chairs.