KR102649408B1 - Manufacturing method of foam sheet for shoe comprising tpu powder and recycled pu scrap powder - Google Patents

Abstract

The present invention relates to a method of manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder. In the present invention, recycled PU (Polyurethane) scrap powder is mixed with polyol for an eco-friendly polyurethane foam composition made of water foam. After mixing it first, the processing speed in the process is controlled through a side-feeder, and TPU (Thermoplastic polyurethane) powder and recycled PU scrap powder are added and reacted secondarily, thereby preventing an increase in the viscosity of the raw materials and producing a larger amount than before. Even if recycled materials are used, it is possible to form foam sheets for shoes, such as foam packages for shoe insoles or shoe uppers, with product quality equivalent to existing products, and the polyurethane foam composition is TPU with an average particle size of 50 to 300㎛. By containing the powder, the process time for putting the polyurethane foam sheet formed from it into a mold and forming it with a heat press is reduced by half, thereby significantly improving product productivity, reducing expensive energy costs, and reducing carbon emissions. Provides a method for manufacturing foam sheets for shoes containing TPU powder and recycled PU scrap powder that can dramatically reduce .

Description

Method for manufacturing foam sheets for shoes containing TPU powder and recycled PU scrap powder {MANUFACTURING METHOD OF FOAM SHEET FOR SHOE COMPRISING TPU POWDER AND RECYCLED PU SCRAP POWDER}

The present invention relates to a method of manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder. More specifically, the present invention relates to an eco-friendly polyurethane foam composition made of water foam by mixing recycled PU scrap powder with polyol and 1. After mixing with tea, TPU powder and recycled PU scrap powder are added and reacted secondarily through a side-feeder, so that even if a larger amount of recycled material is used than before, foam sheets for shoes such as foam packages for shoe insoles or shoe uppers A shoe foam containing TPU powder and recycled PU scrap powder that not only has good product quality, but can also reduce the molding time during the heat press process by half due to the addition of the TPU powder. It relates to the manufacturing method of sheets.

Generally, various types of shoes, such as shoes, sneakers, and hiking boots, have an upper leather that forms the exterior of the shoe, an outsole that is in contact with the ground, a midsole that is installed on the upper side of the sole, and an insole (that is in contact with the sole). It consists of an insole (hereinafter referred to as ‘insole’). At this time, the insole is installed on the inner bottom surface of the shoe to alleviate the impact force applied from the ground to the sole while walking and to improve fit and hygiene.

Shoe insoles such as those described above are being added with various functions based on research results showing that foot health is a very important factor for the human body. For example, many insoles are being molded into ergonomic structures that can effectively absorb shock, or materials are being developed to improve sweat absorption, antibacterial, and deodorizing functions. Recently, shoe insoles have been equipped with heating elements to provide a thermal function. Technology is being proposed to help prevent frostbite during the winter.

In addition, materials commonly used for shoe insoles include polyurethane (PU), ethylene-vinyl acetate (EVA), polyethylene (PE), and latex materials, which are foamed and molded. It is manufactured in the form of a (foam) sheet, and is usually bonded to a fabric woven from natural or artificial fibers using an adhesive or hot melt film.

This adhesion process has the advantage of reducing the process time and number of workers compared to the sewing process by applying liquid adhesive to the adherend and then adhering it to the fabric while drying it to volatilize the solvent or moisture, but it also maximizes cost savings. In order to do this, a process of bonding fabric with a heat press using a thermoplastic hot melt film is widely used instead of using a liquid adhesive, and the foam sheet combined with the fabric as described above is subjected to a high temperature heat press. It is common to go through a molding process to shape the shoe insole.

As a conventional technology for manufacturing the foam sheet for shoes as described above, Republic of Korea Patent Publication No. 10-2009-0086791 (Shin Seung-wook) prevents feet from slipping by attaching it to the bottom of a shoe and provides excellent shock absorption and resilience. In order to have, a cushion layer (10) made by heat-treating high-density polyurethane foam having a density of 0.8 to 1.0 g/cm3, then pressing it with a cooling press, and cutting and molding it into the shape of a shoe cushion; An adhesive layer (20) coated with polyacrylate, natural rubber or synthetic rubber adhesive, or heat-melt adhesive on the surface to which the cushion layer (10) is attached to an adherend; and a release layer (30) protecting the adhesive layer (20); It relates to an adhesive shoe cushion using high-density polyurethane foam, which is formed by sequentially stacking the adhesive layer (20).

In addition, in Patent No. 10-1569659 (Nike Innovate C.V.), the step of placing a desired amount of thermoplastic polyurethane foam beads in a compression mold of the shape of the article, the thermoplastic polyurethane foam beads having a density of 0.01 to 0.3 g/cm3, closing the mold, allowing the mold to reach a maximum temperature of 130° C. to 180° C. over a period of 300 to 1,500 seconds, the maximum temperature being reached. A method of molding a foamed article is disclosed comprising cooling the mold to a temperature of 5° C. to 80° C. over a period of 300 to 1,500 seconds immediately or within 30 seconds thereafter, and removing the article. .

In addition, Patent No. 10-2096984 (BASF SE) is a combination foam comprising a matrix composed of polyurethane foam and expanded particles of thermoplastic polyurethane contained therein, wherein the matrix and particles include a polyol component and a polyurethane component, respectively. It consists of an isocyanate component, and at least 50% by weight of the basic building blocks that form the polyol component of the matrix and particles are the same, and at least 50% by weight of the basic building blocks that form the polyisocyanate component of the matrix and particles are the same. The same applies to combination foams whereby the matrix is completely open cells and the foam particles within the matrix are at least partially closed cells.

And according to the dot composite shoe insole using an adhesive resin mixed with hydrophobic nano-silica and its manufacturing method developed by the present inventor in Korean Patent No. 10-2131606, nano-silica containing a hydrophobic functional group is mixed with the adhesive resin to form an adhesive in the adhesive resin. Dispersibility is improved, water resistance is strengthened, and tensile strength is increased, and the adhesive resin is used to transfer foam and fabric using a transfer roller with a mesh-type engraved dot pattern within the shape of the shoe insole. By being transferred and molded to one side of the fabric, it not only has excellent adhesive performance by preventing overflow, but also has more uniform adhesive strength than conventional products even when a thinner thickness (10 ~ 40㎛) of adhesive resin is applied. It has the effect of securing excellent durability and providing a soft texture while making the product lighter and reducing material costs.

Patent No. 10-2131606 is a transfer roller surface in which the adhesive resin applied to the surface of the transfer roller other than the negative dot pattern is removed and the negative dot pattern is formed in a mesh-type within the shape of the shoe insole. By transferring the adhesive resin applied to one side of the foam or fabric and pressing it, approximately 35 to 40% of the scrap generated after cutting the shape of the shoe insole can be easily separated into each foam and fabric for recycling. This has the advantage of being environmentally friendly and cost-saving.

Meanwhile, in the present invention, for an eco-friendly polyurethane foam composition made of water foam, recycled PU scrap powder is first mixed with polyol, and then TPU powder and recycled PU scrap powder are mixed secondarily through a side-feeder. By adding and reacting, the quality of shoe foam sheet products such as shoe insoles or foam packages for shoe uppers is superior even if a larger amount of recycled material is used than before, and the molding time during the heat press process is reduced. We studied the manufacturing method of foam sheets for shoes that can be shortened.

Republic of Korea Patent Publication No. 10-2009-0086791 (publication date: August 14, 2009) Republic of Korea Patent Publication No. 10-1569659 (announcement date: November 16, 2015) Republic of Korea Patent Publication No. 10-2096984 (announcement date: April 3, 2020) Republic of Korea Patent Publication No. 10-2131606 (announcement date: July 8, 2020)

The purpose of the present invention is to first mix recycled PU (Polyurethane) scrap powder with polyol for an eco-friendly polyurethane foam composition made of water foam, and then adjust the processing speed through a side-feeder. By reacting TPU (Thermoplastic polyurethane) powder and recycled PU scrap powder as a second addition, the viscosity of the raw material is prevented from increasing, making the product a foam for shoe insoles or shoe uppers that is of the same quality as before, even if a larger amount of recycled materials is used than before. A foam sheet for shoes, such as a package, can be formed, and the polyurethane foam composition contains TPU powder with an average particle size of 50 to 300㎛, and the polyurethane foam sheet formed therefrom is placed in a mold and molded by a heat press. Manufacture of shoe foam sheets containing TPU powder and recycled PU scrap powder that can significantly improve product productivity by reducing the process time by half, while reducing expensive energy costs and dramatically reducing carbon emissions. The goal is to provide a method.

The method for manufacturing a shoe foam sheet containing TPU powder and recycled PU scrap powder according to the present invention uses polyol, isocyanate, chain extender, and water as a foaming agent as raw materials. In manufacturing a foam sheet for shoes using a polyurethane foam composition composed of a ratio of 0.1 to 2% by weight, 10 to 20% by weight of recycled PU scrap powder is added based on the total weight of the polyurethane foam composition with respect to the polyol. Preparing a polyurethane foam composition mixed at a ratio (S100); In this regard, 5 to 30% by weight of TPU powder and 10 to 30% by weight of recycled PU scrap powder are added through a side-feeder based on the total weight of the polyurethane foam composition, and then reacted to form polyurethane block foam. Manufacturing step (S200); Cutting the polyurethane block foam to a desired thickness to form a polyurethane foam sheet (S300); Combining the polyurethane foam sheet cut to the desired thickness with fabric (S400); It is characterized by consisting of a step (S500) of putting the polyurethane foam sheet combined with the fabric into a mold and molding and cutting it into a product of a specific shape by heat pressing.

According to a preferred embodiment of the present invention, the recycled PU scrap powder is ground to an average particle size of 50 to 300 ㎛, and the TPU (Thermoplastic polyurethane) powder is virgin TPU with an average particle size of 50 to 300 ㎛. It is characterized in that any one selected from among and recycled TPU is used alone or in a mixture thereof.

The adhesive used in the step of combining the polyurethane foam sheet with the fabric (S400) is a liquid adhesive or hot melt film made of a resin composition selected from thermoplastic polyurethane (TPU) or ethylene vinyl acetate (EVA), The product of a specific shape is characterized as being either a shoe insole or a foam package for a shoe upper.

The method for manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder according to the present invention is to mix recycled PU scrap powder with polyol and 1 for an eco-friendly polyurethane (PU) foam composition made of water foam. After mixing with tea, the processing speed in the process is appropriately adjusted through a side-feeder, and TPU powder and recycled PU scrap powder are added and reacted secondarily, thereby preventing an increase in the viscosity of the raw materials and using a larger amount of recycled materials than before. However, it has the advantage of being able to form foam sheets for shoes, such as foam packages for shoe insoles or shoe uppers, with the same level of product quality as existing products.

In addition, the polyurethane foam composition contains TPU (Thermoplastic polyurethane) powder with an average particle size of 50 to 300㎛, so that the process time for putting the polyurethane foam sheet formed therefrom into a mold and molding by heat pressing is reduced by half. This has the effect of significantly improving product productivity while reducing expensive energy costs and dramatically reducing carbon emissions.

1 is a process flow chart showing a method of manufacturing a foam sheet for shoes according to the present invention.

Hereinafter, a method for manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder of the present invention will be described with reference to the drawings, which will be explained by a person skilled in the art to which the present invention pertains. This is for illustrative purposes to the extent that it can be easily implemented, but this does not mean that the technical idea and scope of the present invention is limited.

In general, polyurethane resin is a resin produced based on a urethane bond created by the reaction of an isocyanate group (-NCO) and a hydroxyl group (-OH) in a polymer, and its raw materials are polyol, isocyanate, It includes chain extenders, etc., and by adjusting the ratio of the soft and hard segments that make up polyurethane, various molecular designs are possible, from products with elasticity like rubber to hard products like plastic.

The characteristics of this polyurethane resin are that it has excellent film strength and adhesive strength, so it is possible to manufacture a thin coating film, and the coating film has high elasticity, so it can be manufactured into a porous film or sheet that is soft to the touch, making it moisture permeable. , it not only provides breathability but also has excellent cold resistance, and because it is processed without using plasticizers, there are fewer workability problems caused by plasticizers.

In addition, the polyol is an active hydrogen compound used to produce polyurethane by reacting with isocyanate. It refers to a compound having two or more active hydrogen groups such as hydroxyl group, carboxyl group, and amine group in the molecule, and has molecular structure, molecular weight, and functional group ( functionality) and the use of various types depending on the OH-value directly affects the physical properties of polyurethane.

For example, polyurethane using polyester polyol has higher tensile strength, hardness, and elongation than polyurethane using polyether polyol, and has excellent flame retardancy as well as excellent chemical resistance and chemical resistance properties, making it resistant to oxidation and superior to polyester. While it has excellent adhesion to various fabrics woven from nylon, etc., its disadvantage is that, unlike polyether polyol, it has the property of being hydrolyzed and has poor water resistance. However, polyurethane using polyether polyol has excellent elasticity, can be used even in high temperature and high humidity environments, and shows excellent durability against acids and alkalis, so it is preferable to use them alone or in combination depending on the application.

In the production of polyurethane (PU) resin, polyurethane is produced when polyether made by polymerization of ethylene oxide is mixed with diisocyanate, and urethane is a mixed amide-ester produced when an alcohol group reacts with isocyanate, and is used instead of diol. When triol is used, cross-linking occurs and thermosetting polyurethane is produced.

Accordingly, the present invention uses a polyurethane foam composition consisting of polyol, isocyanate, chain extender as raw materials, and water as a foaming agent in a ratio of 0.1 to 2% by weight to manufacture shoes. In manufacturing the foam sheet, the polyurethane foam composition is characterized in that it contains 5 to 30% by weight of TPU powder with an average particle size of 50 to 300㎛ and 20 to 50% by weight of recycled PU scrap powder based on the total weight of the polyurethane foam composition. do.

In the present invention, water as a foaming agent is included in the range of 0.1 to 2% by weight based on the total weight of the polyurethane foam composition, thereby having a hardness (ASKER C-Type) of 8 to 40 and a density of 0.05 to 0.35 g/cm3. Foam sheets for shoes (e.g., shoe insoles, foam packages for shoe uppers, etc.) can be formed. Water, a foaming agent, is mixed in advance with the polyol component or later mixed with the isocyanate component and simultaneously mixed with the polyol component. It could be.

The foaming agent can manufacture a polyurethane foam molded body of desired density while minimizing carbon emissions by containing a certain amount of water, a low-carbon source, in consideration of workability and eco-friendliness (water reacts with the isocyanate compound to produce carbon dioxide gas) ), the present invention is a widely used foaming agent that uses fluorinated carbons such as carbon dioxide and chlorofluorocarbons, hydrocarbons such as pentane and cyclopentane, fluorinated hydrocarbons, or air using an air loading device. Research has shown that the method of pre-dispersing nitrogen gas into the polyol component is not desirable considering not only poor workability but also environmental hazards such as carbon emissions and high energy costs.

In the present invention, as a result of numerous trials and errors, the molding time can be significantly shortened by containing 5 to 30% by weight of TPU (Thermoplastic polyurethane) powder with an average particle size of 50 to 300 ㎛ based on the total weight of the polyurethane foam composition. It was discovered that the thermoplastic polyurethane (TPU) powder has excellent physical and chemical miscibility with the polyurethane (PU) foam composition, a polymer resin of the same type, and was found to be a particle with the most suitable mixing properties. By dispersing in size, the moldability by heat press as well as the quality of the product (homogeneity, elasticity, durability) become very good.

The particle size or content of the TPU powder can be adjusted within a specified range depending on the hardness and density of the desired molded body. If the average particle size is less than 50㎛, the mixing ability with the polyurethane foam composition deteriorates, and the 300 If it exceeds ㎛, dispersibility becomes poor, so there is a risk that the defect rate of products manufactured after molding will increase.

In addition, if the content of TPU powder in the polyurethane foam composition is less than 5% by weight, the effect of shortening the molding time by heat pressing is minimal, and if it exceeds 30% by weight, the hardness of the molded body is uniformly formed. Because there are restrictions on setting process conditions for this, it becomes difficult to manufacture a foam molded body with desired elasticity (cushioning properties).

The TPU (thermoplastic polyurethane) is a typical (AB)n type copolymer and is composed of a structure in which hard segments and soft segments are repeated, so it has unique thermal behavior and surface properties, as well as mechanical and physical properties. As it has high toughness and excellent wear resistance, flexibility, and processability, it is widely used as a material for surface coatings and artificial leather, and focuses on the fact that it is an elastic material that can be plasticized by heat even without adding a separate plasticizer. I am leaving it.

The recycled PU scrap used in the present invention is, for example, foam (10) and fabric ( 30) Of course, about 35 to 40% of the scrap generated after cutting the shape of the shoe insole in the combined package can be easily separated into individual foams and fabrics and recycled.

The PU scrap separated from the fabric as described above goes through a step-by-step grinding process, and the recycled PU scrap powder pulverized to an average particle size of 50 ~ 300㎛ is mixed with the raw material (polyol) to uniformly knead with the TPU powder to improve moldability. Not only does it not deteriorate, but it has good elasticity, which is advantageous in ensuring stable product quality.

Accordingly, the present invention contains a certain amount of TPU (Thermoplastic polyurethane) powder with an average particle size of 50 to 300㎛ in an eco-friendly polyurethane (PU) foam composition made of water foam, and the polyurethane foam sheet formed therefrom is placed in a mold and heated. By reducing the molding process time by half by using a heat press, product productivity can be greatly improved, while expensive energy costs can be reduced and carbon emissions can be dramatically reduced.

In addition, the present invention first mixes recycled PU scrap powder with polyol and then secondarily adds TPU powder and recycled PU scrap powder by controlling the process conditions and processing speed through a side-feeder. By reacting to prevent an increase in the viscosity of the raw materials, it is possible to form foam sheets for shoes, such as shoe insoles or foam packages for shoe uppers, with the same level of product quality as before, even if a larger amount of recycled materials are used than before.

As shown in Figure 1, the method of manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder according to the present invention uses polyol, isocyanate, and chain extender as raw materials. In manufacturing foam sheets for shoes using a polyurethane foam composition consisting of 0.1 to 2% by weight of water as a foaming agent, the polyol is recycled based on the total weight of the polyurethane foam composition. Preparing a polyurethane foam composition uniformly mixed with PU scrap powder at a ratio of 10 to 20% by weight (S100); In this regard, 5 to 30% by weight of TPU powder and 10 to 30% by weight of recycled PU scrap powder are added through a side-feeder based on the total weight of the polyurethane foam composition, and then reacted to form polyurethane block foam. Manufacturing step (S200); Cutting the polyurethane block foam to a desired thickness to form a polyurethane foam sheet (S300); Combining the polyurethane foam sheet cut to the desired thickness with fabric (S400); It consists of putting the polyurethane foam sheet combined with the fabric into a mold and molding and cutting it into a product of a specific shape by heat pressing (S500).

First, in the step (S100) of manufacturing the polyurethane foam composition, polyol, isocyanate, chain extender, and water as a foaming agent are composed of 0.1 to 2% by weight. Polyol in the raw materials is first mixed at a ratio of 10 to 20% by weight of recycled PU scrap powder based on the total weight of the polyurethane foam composition. If the recycled PU scrap powder exceeds 20% by weight, the viscosity of the raw materials As it rises, it becomes difficult to mix for future foam reaction, resulting in poor reactivity.

For the above reasons, conventionally, the content of recycled PU scrap powder mixed into the polyurethane foam composition is limited to 20% by weight or less, which is a common practice for recycling waste. Although it was recognized as a limit, in the present invention, the total weight of the polyurethane foam composition is increased by providing a separate side-feeder through which the recycled PU scrap powder can be secondarily introduced to easily control the reaction rate according to the combination of raw materials. As a standard, we have secured a process technology that can contain up to 50% by weight of recycled PU scrap powder in addition to 5 to 30% by weight of TPU powder.

Accordingly, in the present invention, the process conditions and processing speed are adjusted through a side-feeder provided in the step of manufacturing polyurethane block foam (S200), so that the TPU powder is 5 to 5% based on the total weight of the polyurethane foam composition. By adding 30% by weight and 10 to 30% by weight of recycled PU scrap powder, an increase in the viscosity of the raw materials is prevented, making the product for shoe insoles or shoe uppers of the same quality as before, even though a larger amount of recycled materials is used than before. It was confirmed that it was possible to form a foam sheet for shoes like a foam package.

The polyurethane block foam formed as described above is cut to a desired thickness of 1 to 10 mm (usually 2, 4, 5, 6 mm, etc.) to form a polyurethane foam sheet (S300); And the step of combining the polyurethane foam sheet cut to the desired thickness with the fabric (S400). The adhesive used in the step of combining the polyurethane foam sheet with the fabric (S300) is the polyurethane foam sheet ( It is most preferable to use a liquid adhesive or hot melt film made of a resin composition selected from thermoplastic polyurethane (TPU) or ethylene vinyl acetate (EVA), which has excellent compatibility with PU foam sheets.

The adhesive made of thermoplastic polyurethane (TPU) or ethylene vinyl acetate (EVA) is not only environmentally friendly because it does not use solvents, but also has good workability and productivity and is advantageous for securing adhesion to various fabrics due to its flexible material characteristics. , In particular, excellent durability can be secured by maintaining strong adhesion with the polyurethane foam sheet for a long period of time.

Next, a foam sheet for shoes is manufactured through the step (S500) of putting the polyurethane foam sheet combined with the fabric in a mold and molding and cutting it into a product of a specific shape by heat pressing, Typically, when a polyurethane foam sheet combined with the above fabric is placed in a mold and molded by heat press at a temperature of 150 to 200°C and a pressure of 40 to 60 kgf/cm2, the molding time required can be significantly shortened. In the case of shoe insoles, the time can be shortened from about 100 seconds to within 40 to 60 seconds, and the foam package for shoe uppers can be shortened from about 40 seconds to within 10 to 30 seconds.

The most essential feature of the above five-step (S100 ~ S500) process is that it contains 5 to 30% by weight of TPU (Thermoplastic polyurethane) powder with an average particle size of 50 to 300㎛ based on the total weight of the polyurethane foam composition. By doing so, the moldability of the polyurethane foam composition is improved, and the molding time in the step (S400) of processing into a shoe insole shape by heat pressing can be reduced by half.

In addition, recycled PU scrap powder with an average particle size of 50 ~ 300㎛ is first mixed with polyol, and then the processing speed is adjusted through a side-feeder to mix TPU powder and recycled PU scrap powder secondarily. By adding and reacting, an increase in the viscosity of the raw materials can be prevented, making it possible to produce shoe foam sheets such as shoe insoles or shoe upper foam packages with product quality equivalent to existing products, despite using a larger amount of recycled materials than before. It can be formed.

In other words, since the present invention includes TPU powder in the polyurethane foam composition, the molding time for processing into foam sheets for shoes can be reduced by half even if heat pressing is performed under the same temperature and pressure conditions. Of course, it is environmentally friendly and costs can be reduced by recycling PU foam scraps generated in large quantities during the manufacturing process of shoe insoles.

The thermoplastic polyurethane (TPU) powder has excellent chemical miscibility with the polyurethane foam composition, which is a polymer resin of the same type, and is dispersed in a particle size with the most appropriate kneading properties, making it moldable by heat press. This is very good. If the average particle size is less than 50㎛, the kneading property with the polyurethane foam composition deteriorates, and if it exceeds 300㎛, the dispersibility becomes poor, so the defective rate of products manufactured after molding may increase. There are concerns. Also, for the same reason, it is preferable that the maximum particle size of the particles contained in the TPU powder does not exceed 500㎛.

The TPU (Thermoplastic polyurethane) powder is made solely of one type selected from virgin TPU and recycled TPU, for example, recycled TPU obtained by recovering and pulverizing discarded shoe airbags, etc. It can be used or mixed in a certain ratio.

Below, we will look at the manufacturing method of a shoe foam sheet containing TPU powder and recycled PU scrap powder according to the present invention in detail, but it can be easily performed by a person skilled in the art to which the present invention pertains. The present invention will be explained through several preferred embodiments.

[Example 1] Manufacturing of shoe insole

The shoe insole manufactured according to the present invention is manufactured by polymerizing a polyurethane foam composition composed of polyol, isocyanate, chain extender, and water as a foaming agent, and consists of the following five steps.

▶ Step 1: Recycled PU with an average particle size of 150㎛ for the polyol based on the total weight of a polyurethane foam composition containing polyol and isocyanate as raw materials and water as a blowing agent in the range of 0.1 to 2% by weight. A polyurethane foam composition was prepared by mixing scrap powder at a ratio of 10 to 20% by weight.

▶ Step 2: After adding 5 to 30% by weight of TPU powder with an average particle size of 150㎛ and 10 to 30% by weight of recycled PU scrap powder based on the total weight of the polyurethane foam composition through a side-feeder. The reaction was performed to prepare polyurethane block foam.

▶ Third step: The polyurethane block foam was cut to a thickness of 4 mm to form a polyurethane foam sheet.

▶ Step 4: The polyurethane foam sheet cut to a thickness of 4 mm was combined with polyester fiber fabric using a thermoplastic polyurethane (TPU) hot melt film.

▶ Step 5: The polyurethane foam sheet combined with the above fabric was placed in a mold and molded into a drawn insole shape by heat pressing at a temperature of 170°C and a pressure of 50 kgf/cm2 and cut to produce a shoe insole. .

When manufacturing the shoe insole as in Example 1, the fabric and the fabric are heat pressed according to the ratio of the recycled PU scrap powder and TPU powder contained in the polyurethane foam composition in the first and second steps. In order to measure the molding time for processing the combined polyurethane foam sheet into a shoe insole shape in the fifth step, the same type of polyurethane foam sheet without TPU powder as in Comparative Example 1 was processed into a shoe insole shape. The test was compared with time, and the average value of the results of multiple evaluations of molding time, moldability, and appearance condition is shown in [Table 1] below.

division Example
1-1 Example
1-2 Example
1-3 Example
1-4 Example
1-5 Example
1-6 Comparative example
One (Step 1) PU scrap powder (w%) 10 10 15 15 20 20 15 (Step 2) TPU powder (w%) 5 10 15 20 25 30 0 (Step 2) PU scrap powder (w%) 30 25 20 20 15 10 0 (Step 5) Forming time (seconds) 60 57 53 50 45 40 100 Formability and appearance condition Good Good Good Good Good Good Good

[Example 2] Manufacturing of foam package for shoe upper

The foam package for shoe uppers manufactured according to the present invention is manufactured by polymerizing a polyurethane foam composition consisting of polyol, isocyanate, chain extender, and water as a foaming agent as raw materials, and consists of the following five steps.

▶ Step 1: Recycled PU with an average particle size of 150㎛ for the polyol based on the total weight of a polyurethane foam composition containing polyol and isocyanate as raw materials and water as a blowing agent in the range of 0.1 to 2% by weight. A polyurethane foam composition was prepared by mixing scrap powder at a ratio of 10 to 20% by weight.

▶ Step 2: After adding 5 to 30% by weight of TPU powder with an average particle size of 150㎛ and 10 to 30% by weight of recycled PU scrap powder based on the total weight of the polyurethane foam composition through a side-feeder. The reaction was performed to prepare polyurethane block foam.

▶ Third step: The polyurethane block foam was cut to a thickness of 2 mm to form a polyurethane foam sheet.

▶ Step 4: The polyurethane foam sheet cut to a thickness of 2 mm was combined with PU skin film fabric using a thermoplastic polyurethane (TPU) hot melt film.

▶ Step 5: Put the polyurethane foam sheet laminated with the above fabric into a mold and mold and cut it into the shape of a foam package for shoe uppers by heat pressing at a temperature of 170℃ and a pressure of 50kgf/cm2 to create shoe uppers. A foam package was manufactured.

When manufacturing the foam package for shoe uppers as in Example 2, heat press according to the ratio of recycled PU scrap powder and TPU powder contained in the polyurethane foam composition in the first and second steps. In order to measure the molding time for processing a polyurethane foam sheet combined with fabric into a foam package shape for a shoe upper, the same type of polyurethane foam sheet without TPU powder as in Comparative Example 2 was processed into a foam package for a shoe upper. The test was compared with the molding time for processing into the shape, and the average value of the results of several evaluations of the molding time, moldability, and appearance condition is shown in [Table 2] below.

division Example
2-1 Example
2-2 Example
2-3 Example
2-4 Example
2-5 Example
2-6 Comparative example
2 (Step 1) PU scrap powder (w%) 10 10 15 15 20 20 15 (Step 2) TPU powder (w%) 5 10 15 20 25 30 0 (Step 2) PU scrap powder (w%) 30 25 20 20 15 10 0 (Step 5) Forming time (seconds) 25 23 22 20 18 15 40 Formability and appearance condition Good Good Good Good Good Good Good

As shown in [Table 1] and [Table 2], the shoe insoles manufactured according to Examples 1-1 to 1-6 and the foam packages for shoe uppers manufactured according to Examples 2-1 to 2-6 were respectively As in Comparative Example 1 or Comparative Example 2, the quality such as moldability, adhesion between the fabric and the polyurethane foam sheet, and appearance were all found to be excellent. However, if the content of the TPU powder exceeds 30w%, the heat press During molding by heat press, some of the TPU powder present in the polyurethane foam sheet is melted, resulting in overflow at the joint where the fabric and polyurethane foam sheet are combined. It was confirmed that there is a possibility that the density and hardness of the insole product may become uneven.

As described above, the present invention contains TPU powder of a certain particle size in an eco-friendly polyurethane foam composition at an appropriate ratio, and the polyurethane foam sheet combined with the fabric is molded and processed into the shape of a shoe insole by heat pressing. By reducing it by half, product productivity can be greatly improved and expensive energy costs can be reduced.

In addition, the present invention first mixes recycled PU scrap powder with a certain particle size with polyol in a polyurethane foam composition, and then adjusts the process conditions and processing speed through a side-feeder to produce TPU powder and recycling. By reacting with the secondary addition of PU scrap powder, an increase in the viscosity of the raw material is prevented, making foam sheets for shoes such as shoe insoles or foam packages for shoe uppers with the same level of product quality as before, even when using a larger amount of recycled materials than before. It was confirmed that it could be formed.

[Experimental example]

In order to confirm exemplary properties of the polyurethane foam composition according to the present invention, the average particle size is about 150, as in Examples 1-4 and 2-4, within the range of hardness and density required by the present invention. Two types of polyurethane foam sheets (shoe insole, foam package for shoe upper) containing 20% by weight of TPU (Thermoplastic polyurethane) powder of ㎛ and 35% by weight of recycled PU scrap powder were manufactured as existing products. It was manufactured under the same conditions as the heat press (temperature 150 ~ 200℃ & pressure 40 ~ 60kgf/cm2), and the results of several tests for its physical properties are shown in [Table 3] below.

Properties unit shoe insole Foam package for shoe uppers Hardness (ASKER C) - 30/29/29/30/29 19 / 19 / 19 / 20 / 20 density g/㎤ 0.148 / 0.148 / 0.148 0.142 / 0.143 / 0.143 Tear strength kgf/cm 3.1 / 3.0 / 3.1 2.4 / 2.4 / 2.6 tensile strength ㎏f/㎠ 6.4 / 6.1 / 6.6 5.6 / 5.3 / 5.4 elongation % 105 / 105 / 111 123 / 110 / 118 shrinkage rate % 0.18 / 0.17 / 0.15 0.09 / 0.05 / 0.05

- Hardness: ASKER C Type Durometer based on JIS K 7312

As shown in [Table 3], the foam sheet for shoes containing TPU powder and recycled PU scrap powder according to the present invention has phosphorus It was confirmed that the overall physical properties such as thermal strength, tensile strength, elongation, and shrinkage can be manufactured at the same level as existing polyurethane foam sheets that do not contain TPU powder, and the polyurethane foam molded body has hardness (ASKER C-Type ) ranges from 8 to 40 and density within 0.05 to 0.35 g/cm3.

Therefore, the shoe foam sheet containing TPU powder and recycled PU scrap powder manufactured by the present invention can be substituted, modified, and changed into various forms without departing from the technical spirit of the present invention, and is especially environmentally friendly. It has the advantage of reducing productivity and manufacturing costs, so it provides foam packages for various shoe insoles and shoe uppers (decoration) that require uniform formability and durability, as well as clothing and bags made of fiber, natural and synthetic leather, plastic, etc. , It can be applied to a variety of applications that require functions such as molding materials, cushioning materials, and fillers used inside sporting goods, household goods, and industrial products.

Claims (6)

Foam sheets for shoes are manufactured using a polyurethane foam composition consisting of polyol, isocyanate, chain extender as raw materials, and water as a foaming agent in a ratio of 0.1 to 2% by weight. In doing so,
Preparing a polyurethane foam composition mixed with the polyol at a ratio of 10 to 20% by weight of recycled PU scrap powder based on the total weight of the polyurethane foam composition (S100);
In this regard, 5 to 30% by weight of TPU powder and 10 to 30% by weight of recycled PU scrap powder are added through a side-feeder based on the total weight of the polyurethane foam composition, and then reacted to form polyurethane block foam. Manufacturing step (S200);
Cutting the polyurethane block foam to a desired thickness to form a polyurethane foam sheet (S300);
Combining the polyurethane foam sheet cut to the desired thickness with fabric (S400);
Putting the polyurethane foam sheet combined with the fabric into a mold and molding and cutting it into a product of a specific shape by heat pressing (S500);
A method of manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder, characterized in that it consists of. According to paragraph 1,
A method of manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder, characterized in that the recycled PU scrap powder is pulverized to an average particle size of 50 to 300㎛. According to paragraph 1,
The TPU (Thermoplastic polyurethane) powder is a TPU powder selected from virgin TPU and recycled TPU with an average particle size of 50 to 300 ㎛, used alone or in a mixture thereof. Method for manufacturing footwear foam sheets containing recycled PU scrap powder. According to paragraph 1,
The adhesive used in the step of combining the polyurethane foam sheet with the fabric (S400) is a liquid adhesive or hot melt film made of a resin composition selected from thermoplastic polyurethane (TPU) or ethylene vinyl acetate (EVA). A method of manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder. According to paragraph 1,
A method of manufacturing a foam sheet for shoes containing TPU powder and recycled PU scrap powder, wherein the product of the specific shape is any one of a shoe insole or a foam package for a shoe upper. A foam sheet for shoes containing TPU powder and recycled PU scrap powder, characterized in that it is formed by the manufacturing method of any one of claims 1 to 5.