KR20230068446A - An eco-friendly recycled filler masterbatch and a resin composition for a shoe part comprising the same - Google Patents

Abstract

One aspect of the present invention provides an eco-friendly recycled filler masterbatch for shoe members containing a recycled filler and a biodegradable polymer obtained by pulverizing used shoes, and a resin composition for shoe members containing the same. The purpose of the present invention is to improve environmental friendliness in terms of both resource circulation and natural decomposition.

Description

Eco-friendly recycled filler masterbatch for shoe members and resin composition for shoe members containing the same

The present invention relates to an eco-friendly recycled filler masterbatch for shoe members and a resin composition for shoe members comprising the same, and more particularly, to shoe members capable of effectively introducing recycled filler derived from waste shoes and a biodegradable polymer into shoe members. It relates to an eco-friendly recycled filler masterbatch and a resin composition for shoe members comprising the same.

As environmental issues emerge throughout society, policy, management, and R&D in line with ESG (Environmental, Social, Governance) are becoming key trends in the industry. In particular, polymer and rubber materials used as various household items, automobile parts, electrical and electronic product parts, etc., most of the waste generated after use is not rotten and causes environmental pollution problems, so these wastes can be used as shoes and / or Technologies for reusing/recycling as materials for manufacturing clothing are being actively developed.

In particular, among these wastes, rubber wastes such as waste tires, which are representative of waste tires, do not decompose naturally, causing environmental pollution. Technologies are being developed for converting rubber into recycled rubber that can be used as an energy source such as power generation or can replace existing natural rubber and synthetic rubber.

Not only waste tires but also waste shoes are major sources of rubber waste. Shoes are worn to protect the feet of the human body, and are manufactured and sold in various shapes and types. However, they are usually made by increasing friction with the ground while protecting the upper and soles that cover and protect the instep and ankle. It is composed of a sole that improves gaitability and at the same time alleviates the impact applied to the sole of the foot during walking.

The shoe sole is attached to a midsole made of rubber, foamed resin, or sponge material having excellent buffering power to elastically distribute and support the load of the human body during walking and is attached to the bottom surface of the midsole to provide frictional force during walking. It consists of an outsole made of rubber material for The upper is made of various fabrics, and decorations such as metal, plastic, and rubber are attached according to individual designs.

As such, in the case of used shoes, various members are combined by sewing, bonding, and the like, and since it is difficult to physically and chemically separate each of the combined members, research and development on a method for recycling them is insufficient.

On the other hand, in addition to the above-mentioned reuse / recycling of waste, that is, the resource circulation, shoes (or shoe members) applied with biodegradable polymers are being researched and developed so that discarded shoes can be naturally degraded. Some are on the market and are sold at relatively high prices.

However, the essential characteristics of the shoes (or shoe members) to which the biodegradable polymer is applied, for example, impact resistance, durability, comfort, athletic functionality, etc., have a problem that does not reach those of conventional shoes to which synthetic polymers are applied.

The present invention is to solve the problems of the prior art described above, and an object of the present invention is to improve the environmental friendliness in terms of both resource circulation and natural decomposition, and shoes that can implement the essential characteristics that shoe members should have. To provide an eco-friendly recycled filler masterbatch for members and a resin composition for shoe members comprising the same.

One aspect of the present invention provides an eco-friendly recycled filler masterbatch for shoe members comprising a recycled filler obtained by crushing waste shoes and a biodegradable polymer.

In one embodiment, the average particle size of the recycled filler may be 10 ~ 1,000㎛.

In one embodiment, the content of the biodegradable polymer in the master batch may be 5 to 30% by weight.

In one embodiment, the biodegradable polymer is starch, cellulose, lignin, chitosan, chitin, alginic acid, collagen, gelatin, hyaluronic acid, polylactic acid, aliphatic polyester, polyethylene succinate, polybutylene succinate, polycaprolactone , polybutylene adipate-terephthalate, polyglycolic acid, polyhydroxyalkanoate, polyhydroxybutyrate, polyhydroxyvalerate, terephthalic acid, polyvinyl alcohol, pullulan, and a group consisting of two or more combinations thereof may be one selected from

Another aspect of the present invention, 100 parts by weight of the base resin; 1 to 35 parts by weight of filler; and 1 to 30 parts by weight of the eco-friendly recycled filler masterbatch.

In one embodiment, the base resin may be rubber.

In one embodiment, the rubber may include 30% by weight or more of natural rubber, 30% by weight or less of butadiene rubber, and 40% by weight or more of regenerated rubber.

In one embodiment, the base resin may be a foamable resin.

In one embodiment, the foamable resin includes ethylene vinyl acetate and a crystalline polymer, and the content of the crystalline polymer in the foamable resin may be 5 to 30% by weight.

In one embodiment, the filler may be at least one of carbon black and silica.

An eco-friendly recycled filler masterbatch for shoe members and a resin composition for shoe members containing the same according to an aspect of the present invention include a recycled filler obtained by grinding waste shoes and a biodegradable polymer, in terms of both resource circulation and natural degradation. It is possible to improve the environmental friendliness of the shoe member, and to improve the essential characteristics that the shoe member should have.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

Hereinafter, the present invention will be described in detail. However, the present invention may be embodied in many different forms and, therefore, is not limited to the embodiments described herein.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected" but also the case where it is "indirectly connected" with another member interposed therebetween. . In addition, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

Eco-friendly recycled filler masterbatch for shoe parts

One aspect of the present invention provides an eco-friendly recycled filler masterbatch for shoe members comprising a recycled filler obtained by crushing waste shoes and a biodegradable polymer.

The recycled filler may be obtained by (a) washing waste shoes, removing metal members, and then pulverizing to obtain a primary pulverized product, and then (b) heat-treating the primary pulverized product, and eco-friendly recycling for the shoe member. The filler masterbatch may be prepared by mixing (c) the heat-treated primary pulverized material with a biodegradable polymer.

In the step (a), waste shoes, that is, shoe waste, which is a raw material of the recycled filler, may be washed to minimize impurities and remove metal members that may hinder subsequent grinding and heat treatment processes. The washing may be performed by various methods such as air treatment, water treatment, and chemical treatment, but is not limited thereto. Insufficient washing may adversely affect final products due to microorganisms present in used shoes.

It is possible to obtain a first pulverized product having a predetermined average particle size by primarily pulverizing the waste shoes from which the washed and metal members have been removed through the pulverization. The crushing, for example, in the group consisting of a multi-purpose grinder, cutter mill, multi-mill, pin crusher, great mill, roll mill, hammer mill, ball mill, threader, chopper, grind mill, and a combination of two or more of these It may be performed using the selected one, but is not limited thereto. The grinding is 10 to 1,000 rpm, for example, 10 rpm, 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750rpm, 800rpm, 850rpm, 900rpm, 950 rpm, 1,000 rpm or may be performed in a range between the two values of these, but is not limited thereto.

The grinding may be performed by a dry grinding method. Since waste shoes may be insufficiently ground due to their elasticity during wet grinding due to their characteristics, dry grinding may be applied to firstly grind. When the rpm is out of the above range during the crushing, an excessive load may be applied to the tool used for the primary crushing due to metal components present in the reinforcing material, label, etc. in the discarded shoes.

In the step (b), by heat-treating the primary pulverized product at a predetermined temperature, moisture and other impurities that remain in the primary pulverized product and hinder compatibility and miscibility during resin blending may be appropriately removed. The heat treatment may be performed at 30 to 400 °C.

Specifically, when the reclaimed filler itself needs to secure predetermined elasticity and mechanical properties, since the reclaimed filler must include a predetermined amount of polymer components, the primary pulverized product is ground at a low temperature, for example, Heat treatment at 30 to 150 ° C. may selectively remove moisture remaining in the primary pulverized product.

In addition, when it is important to contribute to the compatibility, miscibility, durability of shoe members, and mechanical properties when blending resins, compared to the regenerated filler itself securing predetermined elasticity and mechanical properties, the primary pulverized material is relatively Heat treatment at a high temperature, for example, 150 to 400° C., preferably, 150 to 300° C. to substantially convert ash containing carbon (C) and/or other ceramic components to be applied as a recycled filler. can

Between the steps (a) and (b) and at least one of the steps (b) and (c), (b1) removing the metal material in the primary pulverized material with a magnetic material is further performed. can That is, in the step (b1), the metal material remaining in the primary pulverized product obtained in the step (a) and/or the heat-treated primary pulverized product obtained in the step (b) may be removed. If necessary, the step (b1) may be repeatedly performed in the process of manufacturing the eco-friendly recycled filler masterbatch for the shoe member.

In the step (b1), it is possible to remove a metal component that remains in the first pulverized material and adversely affects a subsequent pulverization process. The metal component may be appropriately removed by the magnetic force of a magnetic material such as a magnet. For example, the step (b1) may be performed by conveying the primary pulverized material using a magnetic conveyor belt.

Shoes may be difficult to pulverize in micro units because they contain many materials that are highly ductile at room temperature, such as textile fabrics. In addition, foams included in shoes may be difficult to pulverize due to elasticity. Therefore, in the step (a), the waste shoes are pulverized to obtain the first pulverized product, and the second or more pulverization is performed at a low temperature so that the first pulverized product does not have ductility and elasticity. may be possible

At least one of the steps (a) and (b) and between the steps (b) and (c), (b2) grinding the primary pulverized product to obtain a secondary pulverized product may be further performed. can That is, in the step (b2), the primary pulverized product obtained in the step (a) and/or the heat-treated primary pulverized product obtained in the step (b) are pulverized so that the particle size is smaller than that of the primary pulverized product. It is possible to obtain the secondary pulverized product having a smaller value. If necessary, the step (b2) may be performed after removing the metal material remaining in the first pulverized material through the step (b1).

In the step (b2), the crushing may be performed by a freeze-grinding method performed at a low temperature, and in this case, the regenerated fine powder may be manufactured from waste shoes by minimizing the action of elasticity and ductility. In addition, the textile fabric included in the shoes forms fluff due to the crushing heat generated during crushing at room temperature to hinder the crushing, but this problem can be solved by applying the freeze crushing method.

In addition, in the process of manufacturing the eco-friendly recycled filler masterbatch for shoe members, (d1) at least one of the products obtained in the steps (b), (b1) and (b2) is subjected to plasma treatment, UV treatment, chemical treatment and these Surface treatment by one method selected from the group consisting of a combination of two or more of; and (d2) reacting the surface-treated primary pulverized material with an alkoxysilane-based compound.

During the plasma treatment, UV treatment, or chemical treatment in step (d1), a hydroxy group (-OH) or a carboxy group (-COOH) may be introduced to the surface of the primary and/or secondary pulverized product. By reacting these functional groups with the alkoxysilane-based compound, a recycled filler having excellent compatibility and bonding strength with respect to the biodegradable polymer may be prepared.

The plasma treatment may be, for example, treatment with low-temperature or high-temperature plasma using at least one of argon, nitrogen, and oxygen, but is not limited thereto. The UV treatment may be surface modification to hydrophilicity by exposing the primary and/or secondary pulverized product to UV with a wavelength of 150 to 300 nm in air, but is not limited thereto. The chemical treatment may be acid treatment or ozone treatment to modify the surface to be hydrophilic, but is not limited thereto.

The alkoxysilane-based compound may be, for example, an aminoalkoxysilane-based compound, but is not limited thereto. The aminoalkoxysilane-based compound may be, for example, 3-aminopropyltriethoxysilane, but is not limited thereto. When an alkoxysilane-based compound is introduced to the surface of the primary and/or secondary pulverized material, the compatibility, miscibility, and resulting bonding strength between the recycled filler constituting the masterbatch and the biodegradable polymer may be improved.

In step (c), a masterbatch may be prepared by mixing the primary and/or secondary pulverized material with a biodegradable polymer. For example, a masterbatch in the form of a pellet may be prepared by blending, kneading, and extruding the primary and/or secondary pulverized material and the biodegradable polymer.

Conventionally, in order to manufacture a shoe member in which eco-friendliness and functionality are balanced, the base resin and the biodegradable polymer have been directly blended, kneaded, and extruded, but due to the heterogeneity of the base resin and the biodegradable polymer, Dispersion was limited. In addition, when directly blending, kneading, or extruding the base resin and the primary and/or secondary pulverized material in particulate form, there is a problem in that the primary and/or secondary pulverized material is also difficult to uniformly disperse in the base resin. .

On the other hand, in the step (c), the first and/or second ground material and the biodegradable polymer are mixed and kneaded with the base resin before mixing the first and/or second ground material and the biodegradable polymer. A completely mixed masterbatch is prepared, and the masterbatch is blended and kneaded with a base resin for manufacturing a shoe member, thereby uniformly dispersing the base resin, the primary and/or secondary pulverized material, and the biodegradable polymer mutually. Accordingly, the physical properties and biodegradability of the manufactured shoe member can be uniformly implemented in the entire area of the shoe.

By heat and shear force applied for blending and kneading of the base resin and the masterbatch, the primary and/or secondary pulverized particulate matter in the masterbatch can be dispersed in the melt of the base resin, In the masterbatch, the biodegradable polymer in solid state bound to at least a part, preferably, the entire surface of the first and / or the second ground material moves along the first and / or second ground material, While being dispersed, it can be melted by heat and uniformly dispersed in the melt of the base resin. That is, in the masterbatch, the primary and/or secondary pulverized material itself is uniformly dispersed to contribute to uniformity of physical properties of each region of the shoe member, as well as to a carrier for uniformly dispersing the biodegradable polymer. Acting as a carrier, it may contribute to equalizing the biodegradability of each region of the shoe member.

The content of the biodegradable polymer in the masterbatch may be 5 to 30% by weight. If the content of the biodegradable polymer in the masterbatch is less than 5% by weight, sufficient biodegradability cannot be implemented, and if it exceeds 30% by weight, the physical properties of the shoe member may be deteriorated.

The biodegradable polymer is starch, cellulose, lignin, chitosan, chitin, alginic acid, collagen, gelatin, hyaluronic acid, polylactic acid, aliphatic polyester, polyethylene succinate, polybutylene succinate, polycaprolactone, polybutylene adipate -Terephthalate, polyglycolic acid, polyhydroxyalkanoate, polyhydroxybutyrate, polyhydroxyvalerate, terephthalic acid, polyvinyl alcohol, pullulan, and may be one selected from the group consisting of combinations of two or more of these , Preferably, it may be starch, polylactic acid and/or polycaprolactone, but is not limited thereto.

Among the biodegradable polymers, starch, cellulose, lignin, chitosan, chitin, alginic acid, collagen, gelatin, hyaluronic acid, etc. may be obtained by separating and purifying materials existing in nature, and may be referred to as so-called natural polymers. In addition, among the biodegradable polymers, polylactic acid, aliphatic polyester, polyethylene succinate, polybutylene succinate, polycaprolactone, polybutylene adipate-terephthalate, polyglycolic acid, polyhydroxyalkanoate, polyhydride The oxybutyrate, polyhydroxyvalerate, terephthalic acid, polyvinyl alcohol, pullulan, and the like may be obtained through chemical and/or biological synthesis.

Resin composition for shoe members

Another aspect of the present invention, 100 parts by weight of the base resin; 1 to 35 parts by weight of filler; and 1 to 30 parts by weight of the eco-friendly recycled filler masterbatch. The resin composition for a shoe member may be applied to a shoe sole such as an insole, midsole or outsole of a shoe and other shoe members having a resin material.

The base resin may be a thermoplastic resin such as a thermoplastic elastomer or a foamable resin and/or a thermosetting resin such as rubber.

The rubber may include one selected from the group consisting of natural rubber, butadiene rubber, styrene-butadiene rubber, isoprene rubber, nitrile rubber, regenerated rubber, and combinations of two or more thereof, but is not limited thereto.

The content of the recycled rubber in the rubber may be 40% by weight or more. The regenerated rubber is rubber that has undergone a desulfurization process, and can be included in a certain amount or more to maximize economic feasibility. The "desulfurization process" is an essential process in the process of regenerating waste rubber that has undergone a vulcanization process in which sulfur is added to natural rubber to enhance physical properties.

When the base resin is rubber, the content of the natural rubber in the rubber may be 30% by weight or more. If the content of the natural rubber is less than 30% by weight, mechanical properties of the shoe member may deteriorate.

The content of the butadiene rubber in the rubber may be 30% by weight or less. If the content of the butadiene rubber exceeds 30% by weight, mechanical properties may be partially improved, but the content of recycled rubber is relatively low, making it difficult to realize effects in terms of eco-friendliness and economy. For example, the rubber may include 30% by weight or more of natural rubber, 30% by weight or less of butadiene rubber, and 40% by weight or more of regenerated rubber.

When the base resin is rubber, the resin composition may further include a sulfur donor, a coupling agent, a crosslinking agent, a crosslinking accelerator, a process oil, and the like, if necessary.

The sulfur donor prevents reduction during the vulcanization process of each rubber, and can serve as a coupling agent or a crosslinking agent for stable vulcanizate production. The sulfur donor is a component used to solve the problem of deterioration of physical properties as a crosslinking agent derived from recycled rubber remains in a composition containing an excessive amount of recycled rubber, and shoes containing an excess of recycled rubber In addition to providing sufficient durability to the outsole, these outsoles of shoes are eco-friendly and economical.

The sulfur donor may mutually crosslink or couple the recycled rubber, natural rubber and butadiene rubber constituting the rubber (heterogeneous rubber crosslinking), and may mutually crosslink or couple each rubber (homogeneous rubber crosslinking) .

The branching degree of regenerated rubber, natural rubber, and/or butadiene rubber may be increased to a required range by the crosslinking or coupling of the rubber, so that processability and mechanical properties of the rubber may be harmoniously implemented.

In the sulfur donor, the number of sulfur atoms included in the functional groups located at both ends of the molecule may affect the branching degree of the crosslinked or coupled rubber and thus the viscosity and processability. That is, if the number of sulfur atoms is small, the viscosity cannot be lowered to a required level, and if the number of sulfur atoms is excessively large, mechanical properties of the product may be deteriorated. The number of sulfur atoms included in functional groups located at both ends of the sulfur donor may be two or more, for example, two or three.

The content of the sulfur donor may be 0.3 to 1.0 parts by weight based on 100 parts by weight of the rubber. If the content of the sulfur donor is less than 0.3 parts by weight, the viscosity of rubber may increase and processability may be deteriorated, and if it is greater than 1.0 parts by weight, mechanical properties of the shoe sole may be deteriorated. The sulfur donor may be at least one of hexamethylene-1,6-bis(thiosulfate) and 1,6-bis(N,N-dibenzylthiocarbamoyldithio)-hexane, but is not limited thereto. .

The hexamethylene-1,6-bis(thiosulfate) may exist as a metal salt, specifically, as a disodium salt dihydrate.

The coupling agent includes functional groups at both ends, and the functional group located at one end reacts with the filler and the functional group located at the other end reacts with the rubber chain to improve the mechanical properties of the shoe sole.

The coupling agent may be silane-based, siloxane-based, a mixture thereof, or a polymer thereof, and may be one modified by a functional group or a substituent, if necessary, and preferably may be a silane-based coupling agent. For example, it may be bis[3-(triethoxysilyl)propyl]tetrasulfide.

The silane-based coupling agent chemically binds the surface of silica, which is a filler, and a rubber chain, thereby improving the interaction and dispersibility between the rubber and the filler, thereby improving mechanical properties of the rubber composite material. The content of the coupling agent may be 2 to 5 parts by weight, but is not limited thereto.

The crosslinking agent is a material that serves as a bridge between rubber chains, and can impart mechanical strength such as hardness and elasticity and chemical stability to rubber for shoe members. The crosslinking agent may be sulfur. The content of the crosslinking agent may be 0.5 to 1.5 parts by weight. If the content of the cross-linking agent is less than 0.5 parts by weight, the viscosity during rubber manufacture may increase and processability may be deteriorated, and if it is greater than 1.5 parts by weight, mechanical properties of the shoe sole may be deteriorated.

The crosslinking accelerator is a component that serves to assist the sulfur donor, and has advantages in that it shortens the vulcanization time, lowers the vulcanization temperature, improves quality, and reduces the amount of vulcanizing agent used, thereby being economically advantageous.

The crosslinking accelerator may be an aldehyde ammonia-based, aldehyde amine-based, guanidine-based, thiourea-based, thiazole-based, thiuram-based, dithiocarbomate-based, xanthate-based, sulfenamide-based, or a mixture thereof, preferably. , thiazole-based, thiuram-based, sulfenamide-based, or mixtures thereof, more preferably, may be thiazole-based and thiuram-based accelerators, but are not limited thereto.

The crosslinking accelerator may include 60 to 80% by weight of a thiazole-based accelerator and 20 to 40% by weight of a thiuram-based accelerator, and mechanical properties of the product may be deteriorated when out of the range.

The thiazole-based accelerator is 2-mercapto banzo thiazole, dibenzothiazyl disulfide, sodium-2-mercapto benzo thiazole, Zn-salt of 2-mercapto banzo thiazole, cyclo of 2-mercapto banzo thiazole It may be one accelerator selected from the group consisting of a hexylamine salt and a combination of two or more thereof, and the thiuram type is tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and dipentamethylene thiuram. It may be one accelerator selected from the group consisting of tetrasulfide and a combination of two or more thereof.

The process oil may be aromatic, naphthenic, or paraffinic oil. In general, compatibility with rubber may be in the order of aromatic, naphthenic, or paraffinic, but paraffinic may be superior in compatibility to butyl rubber. The process oil may affect properties such as compatibility with various rubbers, rubber processability, low-temperature properties of rubber products, anti-fouling properties, aging resistance, elasticity, and abrasion resistance.

Preferably, it may be white oil among paraffinic oils, which is an oil manufactured under long-term accumulated technology and thorough quality control using highly refined paraffinic oil as a raw material, and has excellent oxidation stability, discoloration against light and heat even after long-term use, and It has low contamination and excellent water separation, so it does not cause emulsification when mixed with water, and is advantageous for special rubber compounding.

The foamable resin is a soft or hard polyolefin elastomer, an ethylene-based copolymer, a styrenic copolymer, polyethylene, polypropylene, polyurethane, polyester, nylon, polybutylene terephthalate, polycarbonate, polymethyl methacrylate, poly It may include one selected from the group consisting of oxymethylene and combinations of two or more thereof.

In particular, the foamable resin may be a thermoplastic elastomer, preferably an ethylene-based copolymer. For example, the ethylene-based copolymer may be one selected from the group consisting of ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, and a combination of two or more of them, preferably ethylene vinyl acetate, It is not limited to this.

Conventional shoe members, for example, shoe midsoles, are manufactured using ethylene vinyl acetate and/or polyurethane as a main resin. Polyurethane is relatively superior to ethylene vinyl acetate in terms of durability, processability, moldability, and resilience, but the material itself is heavy, so the weight of shoes increases, and users who wear them inevitably feel fatigue within a short period of time. Ethylene vinyl acetate has excellent light weight, but has a problem in that resilience and durability are lower than polyurethane.

In contrast, the foamable resin includes two types of ethylene vinyl acetate, that is, a first ethylene vinyl acetate, a second ethylene vinyl acetate having a monomer composition different from that of the first ethylene vinyl acetate, and a crystalline polymer, so that conventional ethylene vinyl acetate It is possible to properly compensate for the lack of resilience, durability, mechanical properties, and the durability of these properties.

While the ethylene vinyl acetate itself has excellent light weight, flexibility and adhesiveness of the resin may be determined by the degree of polymerization and the content of vinyl acetate. For example, when the content of vinyl acetate in the ethylene vinyl acetate is increased, flexibility and adhesiveness may be improved. However, as the content of vinyl acetate increases, there is a problem in that processability decreases due to increased adhesiveness during processing.

In addition, it is difficult to sufficiently implement durability and mechanical properties with ethylene vinyl acetate alone, and in particular, since tensile strength and the like decrease when used in a foam form, mechanical properties can be improved by partially crosslinking with a crosslinking agent.

The ethylene vinyl acetate may be prepared by emulsion polymerization, solution polymerization and/or suspension polymerization of monomers.

The emulsion polymerization is a method of emulsifying oil-soluble monomers in water with a surfactant and polymerizing them using a water-soluble initiator. can be obtained The solution polymerization is a method in which an oil-soluble monomer is dissolved in a solvent, for example, an organic solvent, and then polymerized using an initiator. The suspension polymerization is carried out in the micelle of the monomers suspended by dispersing the monomers in a medium in which the monomers are hardly soluble and using a polymerization initiator that is not soluble in the medium but is well soluble in the monomers. Polymerization can proceed as follows.

The content of vinyl acetate in the first ethylene vinyl acetate may be 20 to 30% by weight. If the content of vinyl acetate in the first ethylene vinyl acetate is less than 20% by weight, flexibility and adhesiveness may be deteriorated, and if it is greater than 30% by weight, processability may be deteriorated.

The content of vinyl acetate in the second ethylene vinyl acetate may be 5 to 20% by weight. If the content of vinyl acetate in the second ethylene vinyl acetate is less than 5% by weight, resilience may be reduced, and if it is greater than 20% by weight, workability may be reduced.

The content of the first ethylene vinyl acetate in the foamable resin may be 40 to 90% by weight. If the content of the first ethylene vinyl acetate in the foamable resin is less than 40% by weight, the restoring force may be reduced, and if it is greater than 90% by weight, durability and mechanical properties may be reduced.

The foamable resin may further include a crystalline polymer. The crystalline polymer not only partially improves the physical properties of the shoe member manufactured using the resin composition for shoe members, for example, durability, restoring force, and mechanical properties, but also maintains these characteristics for a long period of time. However, since these crystalline polymers generally have a high processing temperature, for example, a melting point, a softening point, etc., it is difficult to process at about 100 to 150 ° C., which is the processing temperature of the ethylene vinyl acetate. there is

Therefore, when the crystalline polymer has a relatively low processing temperature and thus has good or excellent miscibility and compatibility with the ethylene vinyl acetate, these problems can be appropriately solved.

The crystalline polymer may be a thermoplastic polymer, and the thermoplastic polymer may be, for example, one selected from the group consisting of polyolefin, polyester, polycarbonate, polyamide, polyimide, and combinations of two or more thereof. It may include, preferably, may be polyolefin, but is not limited thereto.

The weight average molecular weight (Mw) of the polyolefin may be 1,000 to 100,000 g/mol, preferably 1,000 to 50,000 g/mol, and more preferably 1,000 to 30,000 g/mol. When the weight average molecular weight of the polyolefin is less than 1,000 g/mol, the melt viscosity is excessively low, resulting in extremely low dispersibility of other components included in the resin composition for shoe members, and in some cases, between the polyolefin and the other components. Phase separation or layer separation may occur. On the other hand, when the weight average molecular weight of the polyolefin is greater than 100,000 g/mol, the melt viscosity increases and processability decreases, which may cause uneven kneading during kneading.

The molecular weight distribution (Mw/Mn) of the polyolefin may be 3 to 7. If the molecular weight distribution of the polyolefin is less than 3, the dispersibility with the other components is lowered, so that the physical properties of the manufactured shoe member may become non-uniform for each part and region, and if it exceeds 7, the mechanical properties of the shoe member may be lowered.

The polyolefin is, for example, one selected from the group consisting of polyethylene, polypropylene, polybutylene, polymethylpentene, ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, and combinations or copolymers of two or more thereof It may be, preferably, polyethylene, more preferably, low density polyethylene (LDPE), but is not limited thereto. Since the low-density polyethylene has a melting point of about 100 to 120° C., miscibility and compatibility with the ethylene vinyl acetate can be appropriately secured.

The content of the crystalline polymer in the foamable resin may be 5 to 30% by weight. If the content of the crystalline polymer in the foamable resin is less than 5% by weight, it is difficult to maintain the physical properties of the shoe member for a certain period of time or more, and if it exceeds 30% by weight, the rebound elasticity of the shoe member and the restoring force thereof may be reduced.

When the base resin is the foamable resin, the resin composition for shoe members may further include one additive selected from the group consisting of a metal oxide, a lubricant, a crosslinking agent, a crosslinking aid, and combinations of two or more thereof.

When the resin composition for shoe members is prepared by including only ethylene vinyl acetate, weight reduction can be realized, but durability and mechanical properties are lowered, which not only increases the defect rate of shoes, but also reduces the user's comfort and fit. However, when a large amount of metal oxide is included, compatibility and processability with the foamable resin are lowered, and as the content of the metal component increases, the weight of the shoe member becomes heavy, which can also act as a factor deteriorating the user's comfort. there is.

Therefore, by including a small amount of a metal oxide in the first and second ethylene vinyl acetate and the crystalline polymer having different monomer compositions, the weight of the shoe can be finally realized, and the durability and resilience of the shoe member can be improved. .

The content of the metal oxide may be 1 to 10 parts by weight based on 100 parts by weight of the foamable resin. If the content of the metal oxide in the resin composition for shoe members is less than 1 part by weight, durability and mechanical properties of the shoe may be reduced, and if it is more than 10 parts by weight, a large amount of metal oxide is included in the composition, resulting in a decrease in the lightness of the shoe. can

The metal oxide may include zinc oxide, titanium oxide, or a combination thereof. The zinc oxide may be included or dispersed in the foamable resin to control a crosslinking rate and promote foaming. The titanium oxide may be included in the resin composition for a shoe member together with the zinc oxide to further promote crosslinking and foaming.

The resin composition for shoe members may include a lubricant, and the lubricant may be, for example, stearic acid, but is not limited thereto. The stearic acid may play a role of uniformly dispersing the resin composition for shoe members. Specifically, the stearic acid is included in the resin composition for shoe members to micronize large particles or agglomerated particles in the composition into smaller particles and uniformly disperse them, thereby preventing aggregation of the particles.

The amount of the lubricant may be 0.1 to 5 parts by weight based on 100 parts by weight of the foamable resin. If the content of the lubricant is less than 0.1 parts by weight, the dispersing effect may be weak, and if it exceeds 5 parts by weight, the viscosity of the resin composition for shoe members may be excessively lowered, resulting in deterioration in processability.

The resin composition for shoe members may contain a foaming agent. The blowing agent may include, for example, one selected from the group consisting of azodicarbonamide, dinitrosopentamethyltetramine, azobisisobutylnitrile, p-toluenesulfonylhydrazide, and combinations of two or more thereof. Yes, preferably, it may be azodicarbonamide, but is not limited thereto.

The amount of the foaming agent may be 0.1 to 10 parts by weight based on 100 parts by weight of the foamable resin. If the content of the foaming agent is less than 0.1 parts by weight, lightness may be reduced, and if it is greater than 10 parts by weight, durability of the shoe member may be reduced.

The crosslinking agent may be a peroxide-based crosslinking agent. The crosslinking agent is, for example, dicumyl peroxide, t-butylperoxylaurylate, t-dibutylperoxymaleic acid, t-butylhydroperoxide, 2,5-dimethyl-2,5-di(t- butyl peroxy) nucleic acid, di-t-butyl peroxide and 1,3-bis (t-butyl peroxy isopropylene) benzene, and may be one selected from the group consisting of combinations of two or more thereof, preferably dicu It may be milperoxide, but is not limited thereto.

The content of the crosslinking agent may be 0.1 to 5 parts by weight based on 100 parts by weight of the foamable resin. If the content of the crosslinking agent is less than 0.1% by weight, durability and mechanical properties of the shoe member may decrease, and if it exceeds 5 parts by weight, flexibility and resilience of the shoe member may decrease.

The cross-linking aid may serve as a cross-linking accelerator that promotes a cross-linking reaction together with the cross-linking agent. The crosslinking aid is, for example, triallyl cyanurate, triallyl isocyanurate, trimethylol, polybutadiene, propane trimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, butyl may include one selected from the group consisting of len glycol acrylate, butylene glycol dimethacrylate, metal-acrylate, metal-methacrylate, and a combination of two or more of them, preferably, triallyl cyanurate It may be, but is not limited thereto.

The content of the crosslinking aid may be 0.1 to 2 parts by weight based on 100 parts by weight of the foamable resin. If the content of the cross-linking aid is less than 0.1 parts by weight, durability and mechanical properties of the shoe member may be reduced, and if it exceeds 2 parts by weight, flexibility and resilience of the shoe member may be reduced.

A shoe member made of the resin composition for shoe members including the foamable resin may satisfy the following conditions. The shoe member may have a hardness (Asker, C) of 40 to 55, a specific gravity of 0.2 to 0.3 g/cc, and tensile strength and tear strength of 15 to 25 MPa and 10 to 20 N/mm, respectively.

<expression>

B/A ≥ 0.9

In the above formula, A is the rebound elasticity (%) measured immediately after manufacturing the shoe member, and is 40 or more, and B is the rebound elasticity (%) measured 7 days after the shoe member is manufactured.

The content of the filler is 1 to 35 parts by weight, for example, 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight based on 100 parts by weight of the base resin. , 35 parts by weight or a range between two of these values. The filler may be at least one of carbon black and silica, preferably, silica, but is not limited thereto.

The content of the eco-friendly recycled filler masterbatch is 1 to 30 parts by weight, for example, 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight based on 100 parts by weight of the base resin. , 30 parts by weight or a range between two of these values. Since the eco-friendly recycled filler masterbatch is prepared by mixing a biodegradable polymer and a pulverized product prepared by pulverizing waste shoes, it may contain foam, rubber, fabric, filler, and a very small amount of adhesive components derived from the waste shoes. there is. In this way, since the eco-friendly recycled filler masterbatch contains a mixture of a material having excellent affinity with the base resin and a material having excellent affinity with the filler, the compatibility of the resin composition for shoe members can be improved by using an appropriate amount. can

The total content of the filler and the environmentally-friendly recycled filler masterbatch is 10 to 35 parts by weight, for example, 10 parts by weight, 15 parts by weight, 20 parts by weight, 30 parts by weight, 35 parts by weight based on 100 parts by weight of the base resin. Or it may be a range between two of these values. If the total content of the filler and the environmentally-friendly recycled filler masterbatch is out of the above range, processability may be deteriorated or mechanical properties may be unsuitable for shoe members.

Unless there is a separate surface treatment, the content of the environmentally-friendly recycled filler masterbatch relative to the total content of the filler and the environmentally-friendly recycled filler masterbatch may be 90% by weight or less. If the ratio of the eco-friendly recycled filler masterbatch is out of the above range without separate treatment, the processability of the resin composition for shoe members may be deteriorated, and mechanical properties may be deteriorated due to poor dispersibility in the base resin.

In addition, when the filler is silica, the surface of the primary and/or secondary pulverized material may be modified with organosilane. Foams, rubbers, etc. included in the primary and/or secondary pulverized materials may have insufficient compatibility with silica, but are modified with organosilane to improve affinity with hydrophilic silica to improve mechanical properties of the final product. can be significantly improved. Such organosilane modification may be performed by forming a hydroxy group (-OH) or carboxy group (-COOH) on the surface through surface treatment such as plasma treatment or UV treatment, and then reacting with aminoalkoxysilane, etc., but is not limited thereto. .

The average particle size of the primary and / or secondary pulverized material is 10 to 1,000 μm, for example, 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm ㎛, 500㎛, 550㎛, 600㎛, 650㎛, 700㎛, 750㎛, 800㎛, 850㎛, 900㎛, 950㎛, 1,000㎛ and may be a range between two of these values. If the average particle size of the primary and/or secondary pulverized materials is out of the above range, fine pulverization may be substantially impossible or the size of the pulverized materials may become excessively large, resulting in deterioration in dispersibility in the expandable resin matrix. The particle size can be realized by grinding the waste shoes one or more times by milling after washing, heat treatment before and/or after grinding, and/or removing metal components, and as a result, compatibility with the base resin matrix and filler is improved. can do.

Hereinafter, specific embodiments of the present invention will be described in detail.

reference example

Washed shoe waste was pulverized using a milling grinder. Grinding was continuously performed, but a filler having an average particle size of less than 1.0 mm could not be prepared.

Comparative Preparation Example 1

The first crushing of the washed shoe waste was performed using a milling grinder. The primary pulverized material was transferred to a magnetic conveyor, and metal components located on reinforcing materials and labels were removed. A recycled filler (1) was prepared by performing secondary grinding using a freeze mill.

Comparative Preparation Example 2

The first crushing of the washed shoe waste was performed using a milling grinder. The primary pulverized material was transferred to a magnetic conveyor, and metal components located on reinforcing materials and labels were removed. After performing secondary grinding using a freeze mill, the surface was treated with plasma to form a hydroxyl group, and then reacted with 3-aminopropyltriethoxysilane to prepare a regenerated filler (2).

Comparative Preparation Example 3

The first crushing of the washed shoe waste was performed using a milling grinder. The recycled filler 3 was prepared by heat-treating the primary pulverized material in an oven at 200° C. for 2 hours.

Preparation Example 1

The first crushing of the washed shoe waste was performed using a milling grinder. The primary pulverized material was transferred to a magnetic conveyor, and metal components located on reinforcing materials and labels were removed. Recycled filler was prepared by performing secondary grinding using a freeze mill. The recycled filler and polycaprolactone were kneaded and extruded at a weight ratio of 90:10 at 160° C. to prepare a masterbatch (1) in the form of pellets.

Preparation Example 2

The first crushing of the washed shoe waste was performed using a milling grinder. The primary pulverized material was transferred to a magnetic conveyor, and metal components located on reinforcing materials and labels were removed. After performing secondary grinding using a freeze mill, the surface was treated with plasma to form a hydroxyl group, and then reacted with 3-aminopropyltriethoxysilane to prepare a recycled filler. The recycled filler and polycaprolactone were kneaded and extruded at a weight ratio of 90:10 at 160° C. to prepare a masterbatch (2) in the form of pellets.

Preparation Example 3

The first crushing of the washed shoe waste was performed using a milling grinder. The primary pulverized material was heat-treated in an oven at 200° C. for 2 hours to prepare a recycled filler. The recycled filler and polycaprolactone were kneaded and extruded at a weight ratio of 90:10 at 160° C. to prepare a masterbatch (3) in the form of pellets.

Example 1 and Comparative Example 1

Rubber, metal oxide, stearic acid, anti-aging agent according to the mixing ratio (unit: parts by weight) in Tables 1 and 2 below while maintaining a speed of 50 to 70 rpm in a Banbury mixer maintained at 70 ° C. , A surfactant and a metal/fatty acid-based processing aid were added and mixed for 5 minutes, followed by additional addition of a filler, coupling agent and process oil, followed by additional mixing for 10 minutes.

Again, while maintaining the speed of 40 to 60 rpm in an open roll-mill maintained at 70 ° C., the crosslinking agent and crosslinking accelerator were added to the mixture according to the mixing ratio (unit: parts by weight) of Tables 1 and 2 below. And a sulfur donor was added and mixed for 5 minutes, and then the rubber compositions for shoe outsoles of Examples and Comparative Examples were prepared into 1 to 2 mm sheets, and mold thicknesses were 2 mm and 5 mm, respectively, at 160 ° C. A specimen was prepared by press molding for 6 minutes under a press condition of 120 kgf/cm ² .

-1) KBR 01, Kumho Petrochemical

-2) Zeosil 175MP, Rhodia

-3) Si-69, Rhodia

-4) W-1500, Michang Petrochemical

-5) DM, OCI

division Example
1-1 Example
1-2 Example
1-3 Example
1-4 Example
1-5 Example
1-6 Example
1-7 recycled rubber 40 50 50 30 40 30 30 caoutchouc 30 30 - 40 40 40 40 Butadiene rubber ¹⁾ 30 20 50 30 20 30 30 Silica ²⁾ 35 25 35 20 30 20 15 Masterbatch (1) 10 15 - - - - - Masterbatch (2) - - 10 20 - - - Masterbatch(3) - - - - 10 20 25 Coupling agent ³⁾ 3 3 3 3 3 3 3 processing aid One One One One One One One metal oxide 5 5 5 5 5 5 5 stearic acid 2 2 2 2 2 2 2 antioxidant One One One One One One One Surfactants One One One One One One One Process oil ⁴⁾ 2 2 2 2 2 2 2 cross-linking agent (sulfur) 1.2 1.2 1.2 1.2 1.2 1.2 1.2 cross-linking accelerator ⁵⁾ 1.2 1.2 1.2 1.2 1.2 1.2 1.2

division comparative example
1-1 comparative example
1-2 comparative example
1-3 comparative example
1-4 recycled rubber 30 30 30 30 caoutchouc 40 40 40 40 Butadiene rubber ¹⁾ 30 30 30 30 Silica ²⁾ 40 35 35 355 Regeneration Filler(1) - 10 - - Regeneration Filler(2) - - 10 - Regeneration Filler(3) - - - 10 Coupling agent ³⁾ 3 3 3 3 processing aid One One One One metal oxide 5 5 5 5 stearic acid 2 2 2 2 antioxidant One One One One Surfactants One One One One Process oil ⁴⁾ 2 2 2 2 cross-linking agent (sulfur) 1.2 1.2 1.2 1.2 cross-linking accelerator ⁵⁾ 1.2 1.2 1.2 1.2

Experimental Example 1

The mechanical properties of the specimens of the Examples and Comparative Examples, except for some comparative examples in which preparation of specimens was impossible, were measured by the following method, and the results are shown in Table 3 below.

-Hardness (Shore A): Measured using an Asker A type durometer according to KS M6518.

-Tensile strength (kgf/cm ² ): Tensile strength was measured according to KS M6518. At this time, the number of test pieces used in the same test was five.

-Tear strength (kgf/cm): Tear strength was measured according to KS M6518. At this time, the number of test pieces used in the same test was 5.

- Abrasion resistance (%): measured using an NBS abrasion tester (KS M6625). After testing the standardized specimens 5 or more times, the average was taken as the test value, excluding the maximum and minimum values.

division Hardness tensile strength tear strength NBS wear Example 1-1 70 156 87 202 Example 1-2 71 151 85 186 Example 1-3 72 159 90 211 Example 1-4 69 156 88 195 Example 1-5 73 167 96 237 Example 1-6 71 164 94 234 Examples 1-7 70 161 90 221 Comparative Example 1-1 69 157 88 198 Comparative Example 1-2 68 153 85 193 Comparative Example 1-3 70 155 87 199 Comparative Example 1-4 71 163 91 224

Example 2 and Comparative Example 2

First ethylene vinyl acetate (EVA1) containing 28% by weight of vinyl acetate, second ethylene vinyl acetate (EVA2) containing 18% by weight of vinyl acetate, and low density polyethylene (LDPE, Tm = 110 ° C.) Foaming resin, silica , Masterbatch and recycled filler, zinc oxide, stearic acid, dicumyl peroxide, triallyl cyanurate, and azodicarbonamide obtained in the above Preparation Examples and Comparative Preparation Examples in the mixing ratios of Tables 4 and 5 (unit: weight) Part) was put into a kneader and kneaded at 70 ° C. for 10 minutes to prepare a resin composition for shoe members.

The resin composition for shoe members is first pressed at 90°C, 140kgf/cm2, for 8 minutes using a pouring foam molding method to make a preform in the form of a sheet, then put it in a mold and press 2 at 160°C, 150kgf/cm2, 15 minutes 2 After the car press, it was cooled in a cooling press for 10 minutes to prepare a shoe midsole.

division Example 2-1 Example 2-2 Example 2-3 Example 2-4 EVA1 50 45 43 40 EVA2 45 45 42 30 LDPE 5 10 15 30 silica 25 20 15 5 Masterbatch (1) 5 - - - Masterbatch (2) - 10 - - Masterbatch(3) - - 15 30 zinc oxide 3 3 3 3 stearic acid One One One One Dicumyl Peroxide One One One One triallyl cyanurate One One One One azodicarbonamide 6 6 6 6

division Comparative Example 2-1 Comparative Example 2-2 Comparative Example 2-3 Comparative Example 2-4 Comparative Example 2-5 EVA1 50 45 43 40 45 EVA2 45 45 42 30 45 LDPE 5 10 15 30 10 silica 25 20 15 5 35 Regeneration Filler(1) 5 - - - - Regeneration Filler(2) - 10 - - - Regeneration Filler(3) - - 15 30 - zinc oxide 3 3 3 3 3 stearic acid One One One One One Dicumyl Peroxide One One One One One Triallyl cyanurate One One One One One azodicarbonamide 6 6 6 6 6

Experimental Example 2

The physical properties of the shoe midsoles manufactured according to the above Examples and Comparative Examples were evaluated, and the results are shown in Tables 6 and 7 below. The physical property evaluation method is as follows.

-Hardness (Asker, C): measured using an Asker C-type durometer according to KS M 6660.

-Specific gravity (g/cc): Measured 5 times using an automatic specific gravity measuring device manufactured by Ueshima Co. according to KS M 6660 and expressed as an average value.

- Tensile strength (MPa): measured using a Zwik universal testing machine according to KS M ISO 1798.

-Tear strength (N/mm): measured according to KS M ISO 7214 using a Zwik universal testing machine.

- Resilience (%): Measured according to KS M ISO 8307 using a rebound resilience tester from Daesung Science.

division Hardness importance tensile strength tear strength Example 2-1 47 0.2 23 15 Example 2-2 49 0.2 22 14 Example 2-3 52 0.2 22 12 Example 2-4 55 0.2 21 14 Comparative Example 2-1 46 0.2 19 11 Comparative Example 2-2 48 0.2 18 13 Comparative Example 2-3 51 0.2 16 10 Comparative Example 2-4 53 0.3 15 12 Comparative Example 2-5 54 0.3 20 10

division Resilience immediately after manufacturing (A) Resilience after 7 days (B) B/A Example 2-1 43.1 41.1 0.954 Example 2-2 41.8 39.5 0.944 Example 2-3 42.2 39.1 0.927 Example 2-4 40.5 37.9 0.935 Comparative Example 2-1 43.9 40.1 0.914 Comparative Example 2-2 41.8 38.6 0.924 Comparative Example 2-3 40.1 37.4 0.933 Comparative Example 2-4 41.1 38.1 0.927 Comparative Example 2-5 39.3 37.8 0.962

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the claims of this specification, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention.

Claims (10)

Containing recycled fillers and biodegradable polymers obtained by crushing waste shoes,
Eco-friendly recycled filler masterbatch for shoe members. According to claim 1,
The average particle size of the recycled filler is 10 to 1,000 μm,
Eco-friendly recycled filler masterbatch for shoe members. According to claim 1,
The content of the biodegradable polymer in the masterbatch is 5 to 30% by weight,
Eco-friendly recycled filler masterbatch for shoe members. According to claim 1,
The biodegradable polymer is starch, cellulose, lignin, chitosan, chitin, alginic acid, collagen, gelatin, hyaluronic acid, polylactic acid, aliphatic polyester, polyethylene succinate, polybutylene succinate, polycaprolactone, polybutylene adipate -One selected from the group consisting of terephthalate, polyglycolic acid, polyhydroxyalkanoate, polyhydroxybutyrate, polyhydroxyvalerate, terephthalic acid, polyvinyl alcohol, pullulan, and combinations of two or more thereof,
Eco-friendly recycled filler masterbatch for shoe members. Base resin 100 parts by weight;
1 to 35 parts by weight of filler; and
1 to 30 parts by weight of the eco-friendly recycled filler masterbatch according to any one of claims 1 to 4;
A resin composition for shoe members. According to claim 5,
The base resin is rubber,
A resin composition for shoe members. According to claim 6,
The rubber includes 30% by weight or more of natural rubber, 30% by weight or less of butadiene rubber, and 40% by weight or more of regenerated rubber.
A rubber composition for shoe members. According to claim 5,
The base resin is a foamable resin,
A resin composition for shoe members. According to claim 8,
The foamable resin includes ethylene vinyl acetate and a crystalline polymer,
The content of the crystalline polymer in the foamable resin is 5 to 30% by weight,
A resin composition for shoe members. According to claim 5,
The filler is at least one of carbon black and silica,
A resin composition for shoe members.