High-functional foaming resin composition and preparation method thereof

Abstract

The present invention relates to a high-functional foaming resin composition and a preparation method thereof, and in particular, to a high-functional foaming resin composition capable of providing high split tear strength and high resilience when preparing shoemaking materials such as insoles, midsoles, and outsoles and a preparation method thereof.

Description

Technical Field

[0001] The present invention relates to a high-functional foaming resin composition and a preparation method thereof, and in particular to a high-functional foaming resin composition capable of providing high split tear strength and high resilience when manufacturing shoemaking materials, such as insoles, midsoles, outsoles, etc., and a preparation method thereof. Background Art

[0002] Polymer foam refers to a dual state object in which bubbles coexist in a solid polymer. It is widely used in a variety of applications such as water-absorbing materials, cushioning materials, heat-insulating materials, sound-absorbing materials, various substrates such as circuit boards, and supports. Most of the fibers and leathers that have been widely used in the past are polymer materials and are porous materials. The first artificially made foam was natural latex foam, and then synthetic latex and the like were used as raw materials for foam. Recently, it is developing towards various plastic foams with elasticity such as polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC), and research on the types of foams and their foaming technologies is being actively carried out. Polyolefin foams are used in the automotive, packaging, construction, marine, pharmaceutical, sports, and leisure industries due to their excellent lightness, chemical resistance, impact absorption, heat insulation, and sound insulation. Among them, ethylene vinyl acetate (EVA) is widely used in the automotive industry and electrical and electronic products due to its excellent flexibility, impact strength, transparency, processability, and ozone resistance. In particular, foams are widely used as insoles and midsoles in the shoe industry as cushioning materials due to their low specific gravity, soft touch, and appropriate strength and impact properties.

[0003] In general, the physical properties of polymer foams are affected by the mechanical properties of the base resin of the foam and the cell structure such as open cell content, size, size distribution, morphology, etc., as well as by many variables such as the concentration of cross-linking agents, additives such as nucleating agents, processing technology, and processing conditions. A lot of research is being conducted on this.

[0004] For example, Korean Patent No. 10-2017-0081949 discloses a microporous foamed nanocomposite material and a preparation method thereof, wherein the microporous foamed nanocomposite material comprises a polymer elastomer, a nanofiller, at least two amphiphilic polymers, a chemical foaming agent, a foaming promoter, and a cross-linking agent, which can provide enhanced physical properties of the microporous foamed nanocomposite material and can be produced on a large scale commercially.

[0005] In addition, Japanese Patent No. 6026895 discloses a foam resin composition comprising a biodegradable resin, a polypropylene resin, a flexible polymer and a core agent, which can provide a high foaming rate, excellent strength, flexibility and resilience, wherein the biodegradable resin comprises starch.

[0006] In addition, Japanese Patent Laid-Open No. 2013-159632 provides a thermoplastic elastomer composition comprising an ethylene-vinyl acetate copolymer, a diene compound, and an olefin copolymer to provide a foam having excellent flexibility, molding processability, strength, and the like.

[0007] As described above, the development of foam compositions aiming to provide excellent physical properties is actively being carried out, and in order to provide even better physical properties, development research is still needed. In view of the above, the present invention has been completed, and in particular, a high-functional foaming composition with excellent split tear strength and rebound resilience is provided by adjusting the type and size of a nucleating agent contained in a polymer foam.

[0008] Prior Art Literature

[0009] (Patent Document 1) Korean Patent Publication No. 10-2017-0081949 (July 13, 2017)

[0010] (Patent Document 2) Japanese Patent Publication No. 6026895 (November 16, 2016)

[0011] (Patent Document 3) Japanese Patent Publication No. 2013-159632 (August 19, 2013) Summary of the invention

[0012] Technical issues

[0013] The object of the present invention is to solve all the above problems.

[0014] The present invention aims to provide a highly functional foaming composition having excellent split tear strength and rebound resilience, and in particular, to improve mechanical properties by adjusting the type and size of a nucleating agent contained in a polymer foam.

[0015] An object of the present invention is to provide a highly functional foaming composition as a shoe-making material.

[0016] Technical Solution

[0017] The characteristic configuration of the present invention in order to achieve the above-mentioned object of the present invention and realize the characteristic effects of the present invention described later is as follows.

[0018] According to one embodiment of the present invention, a foaming resin composition is provided. Relative to 100 parts by weight of the blended resin, the foaming resin composition comprises 0.1 to 10 parts by weight of a silica nucleating agent, 0.1 to 5 parts by weight of a cross-linking agent, 1 to 20 parts by weight of a foaming agent and 1 to 10 parts by weight of a foaming aid.

[0019] According to an embodiment of the present invention, the blended resin includes 20 to 80 parts by weight of olefin elastomer relative to 20 to 80 parts by weight of ethylene-vinyl acetate copolymer (EVA).

[0020] According to an embodiment of the present invention, a material comprising the foaming resin composition is provided, which can be used for shoe-making materials.

[0021] According to one embodiment of the present invention, there is provided a method for preparing a foaming resin composition, the method comprising the following steps: step (a), preparing a blended resin comprising ethylene-vinyl acetate copolymer (EVA) and an olefin elastomer; step (b), adding a silica nucleating agent to the blended resin, and performing a first kneading; step (c), adding a cross-linking agent, a foaming agent and a foaming aid to the blended resin, and performing a second kneading.

[0022] According to one embodiment of the present invention, the preparation method adopts a melt blending method, and at least one selected from an extruder, a kneader, a Brabender plasticizer, a mixing roll and a mixer can be used.

[0023] Beneficial Effects

[0024] The foaming resin composition of the present invention can provide excellent split tear strength and resilience during foaming, and can also provide excellent hardness, density and energy loss coefficient, thereby being used as a shoemaking material.

[0025] The shoe material comprising the foaming resin composition of the present invention can provide excellent wear resistance, impact resistance and lightness. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A scanning electron microscope (SEM) photograph of the foaming composition of Comparative Example 1 of the present invention is shown.

[0027] Figure 2 A scanning electron microscope (SEM) photograph of the foaming composition of Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0028] Hereinafter, the configuration and function of the present invention will be described in more detail through the preferred embodiments of the present invention. However, these are preferred examples of the present invention and the present invention cannot be construed as being limited thereto in any sense.

[0029] The contents not described here can be fully deduced by those skilled in the art, and thus the description thereof is omitted.

[0030] Preparation Example 1: Preparation of foaming resin composition

[0031] A twin screw extruder (27 mm Φ) from Leistritz was used to prepare the blended resin at a processing temperature of 140 to 160° C. The screw speed was 200 to 250 rpm and the feeding rate was 8 to 9 kg / h.

[0032] Afterwards, a non-reactive nucleating agent is first added at a temperature of 100-110° C. in a two roll mill and kneaded for the first time. Then, a crosslinking agent, a foaming agent and a foaming aid are added and kneaded for further 5 minutes to minimize the early decomposition of the foaming agent that may occur in the process of preparing the blend, and to prepare a resin composition for foaming.

[0033] Preparation Example 2: Preparation of Foam (Preform) and Phylon

[0034] 87 g of the sheet-shaped foaming resin composition was placed in the corresponding foaming mold and heated at 150 kg / cm 2 , 165°C, crosslinked / foamed for 10 minutes to prepare a preform (Pre-Form) (foaming ratio is 180%). The 10 mm thick sample for physical property measurement is made by cutting the preform (Pre-Form) with a slicer (Slicer) and then compressing it to form a phylon. The preform (Pre-Form) is cut into a size of 80×180×18 (W×L×H, mm) and placed in a phylon molding mold. After heating at 165°C for 380 seconds, it is cooled for 380 seconds and compressed to a thickness of 10 mm to prepare phylon.

[0035] Example 1

[0036] The resin provided in Preparation Example 1 is a blended resin, which comprises 5 parts by weight of a silica nucleating agent, 0.6 parts by weight of a cross-linking agent (DCP), 10.4 parts by weight of a foaming agent (JRT-M), and 3 parts by weight of a foaming aid (ZnO), relative to 50 parts by weight of ethylene-vinyl acetate copolymer (EVA) and 50 parts by weight of ethylene propylene diene monomer (EPDM).

[0037] At this time, the nucleating agent is a silica nucleating agent (OCI KONASIL K-300) with a size of 7 to 40 nm.

[0038] According to Preparation Example 2, the foaming resin composition of Preparation Example 1 was made into a preform, and the results of the test according to the experimental example in Table 1 below are shown in Table 2.

[0039] Comparative Example 1

[0040] The same procedure as in Example 1 was carried out except that the nucleating agent was a silica nucleating agent (DEUREX S3012M) and the size was 12 μm or less.

[0041] Comparative Example 2

[0042] The same procedure as in Example 1 was carried out except that the nucleating agent was a silica nucleating agent (DEUREX S3017M) and the size was 17 μm or less.

[0043] Comparative Example 3

[0044] The same method as Example 1 was followed except that the nucleating agent provided a silica nucleating agent (ABC Nanotech SILNOS 230) and the size was 2 to 4 μm or less.

[0045] Comparative Example 4

[0046] The same method as in Example 1 was carried out except that the nucleating agent was a calcium carbonate nucleating agent (BUWON B-50CaCO3) and the size was 50 μm or less.

[0047] Comparative Example 5

[0048] The same method as Example 1 was carried out except that the nucleating agent was talc (KOCH KC-5000C) and the size was 3.5±0.5 μm.

[0049] Comparative Example 6

[0050] The same procedure as in Example 1 was followed except that the nucleating agent was talc (KOCH KCNAP-400) and the size was 11.0±2.0 μm.

[0051] Embodiment 2 to Embodiment 6

[0052] The same procedure as in Example 1 was followed, except that Example 2 contained 0.1 parts by weight of a nucleating agent, Example 3 contained 0.3 parts by weight of a nucleating agent, Example 4 contained 0.7 parts by weight of a nucleating agent, Example 5 contained 1 part by weight of a nucleating agent, and Example 6 contained 3 parts by weight of a nucleating agent.

[0053] Comparative Example 7

[0054] The same procedure as Example 1 was followed except that no nucleating agent was included.

[0055] Experimental example: Physical property evaluation

[0056] As shown in Table 1 below, the physical properties of the foams (preforms) and phylons prepared according to the above examples and comparative examples were evaluated.

[0057] Table 1

[0058]

[0059] Table 2

[0060]

[0061]

[0062] By looking at Table 2 which is the physical property evaluation results of Table 1, it can be confirmed that in Example 1 where the size of the silica nucleating agent is 7 to 40 nm, the cell morphology can be changed when forming foam to form microbubbles, thereby improving the mechanical properties of the foam.

[0063] From Table 2, it can be confirmed that in the measured values ​​of phylon properties with different contents of nucleating agents, the more nano-sized silica nucleating agents are included, the greater the split tear strength (STS), but the smaller the resilience. Therefore, it can be confirmed that Example 3 is the optimal value, and in Example 3, while providing an appropriate split tear strength (STS) of more than 2.0 kgf / cm, the resilience and energy loss coefficient are both excellent.

[0064] That is, through experiments, it can be confirmed that the particle size has the greatest influence on the nucleation effect, and the nano-sized particle-shaped nucleating agent improves the nucleation effect due to its large specific surface area, thereby providing a foam with microbubbles, and further providing a foaming composition with excellent split tear strength (STS) and resilience as well as excellent elasticity and hardness.

[0065] Therefore, it was confirmed that by providing the foaming composition of the present invention, a highly functional composition having excellent split tear strength and rebound resilience can be provided, and the composition can be used for shoe materials.

[0066] The present invention has been described above through specific matters such as specific constituent elements and limited embodiments, but this is only for a more comprehensive understanding of the present invention. The present invention is not limited to the above-mentioned multiple embodiments, and those skilled in the art can make various modifications and variations from these descriptions.

[0067] Therefore, the concept of the present invention is not limited to the embodiments described above, and the attached claims and their equivalents or equivalents all belong to the scope of the concept of the present invention.

[0068] Implementation

[0069] The detailed description of the present invention described below will refer to specific embodiments that can implement the present invention as examples. These embodiments are described in detail so that those skilled in the art can sufficiently implement the present invention. The various embodiments of the present invention are different from each other but are not necessarily mutually exclusive. For example, the specific properties, structures and characteristics recorded herein can be associated with an embodiment, and can be implemented with other embodiments without departing from the spirit and scope of the present invention. In addition, it should be understood that the position or configuration of individual constituent elements within each disclosed embodiment can be changed without departing from the spirit and scope of the present invention. Therefore, the detailed description described below is not intended to adopt a restrictive meaning, and as long as it is properly stated, the scope of the present invention is limited only by the attached claims and their equivalents.

[0070] Hereinafter, the present invention will be described in detail with reference to several preferred embodiments so that those skilled in the art can easily implement the present invention.

[0071] According to the present invention, a highly functional foaming resin composition and a method for preparing the same are provided.

[0072] According to an embodiment of the present invention, a blended resin includes ethylene-vinyl acetate copolymer (EVA) and an olefin elastomer.

[0073] According to one embodiment of the present invention, the blended resin contains 80 to 20 parts by weight of olefin elastomer relative to 20 to 80 parts by weight of ethylene-vinyl acetate copolymer (EVA). In the blended resin, when the proportion of the olefin elastomer is less than 20 parts by weight, the crystallinity of the resin increases, resulting in reduced elasticity of the resin, and when it is greater than 80 parts by weight, the processability is reduced, and physical properties such as expansion ratio or split tear strength (STS) are reduced.

[0074] The ethylene-vinyl acetate copolymer (EVA) of the present invention refers to a polymer copolymerized from ethylene and vinyl acetate monomers, and generally has the characteristics of the basic properties of polyethylene products prepared from ethylene monomers and the properties of vinyl acetate. Compared with ethylene monomers, vinyl acetate monomers contain acetoxy groups, so the higher their content, the stronger their polar properties. As the content of vinyl acetate increases, optical properties (glossiness) are improved, and density increases, but flexibility increases due to reduced crystallinity. In addition, in the blended resin, the cross-linking reactivity of the cross-linking agent is affected by the molecular structure, and the more functional groups there are, the stronger the cross-linking reactivity is.

[0075] The content of vinyl acetate (VA) in the ethylene-vinyl acetate copolymer (EVA) is 10 to 50% by weight. When the content is less than 10% by weight, processing is difficult, and when it is greater than 50% by weight, it is not good for crystallinity. In addition, the greater the content of acetoxy in the ethylene-vinyl acetate copolymer, the better the crosslinking reactivity, but when it is too much, control to prevent crosslinking is required in the process, so the above range is preferred.

[0076] The melt flow index of the ethylene-vinyl acetate copolymer (EVA) can be 1 to 10, and the viscosity analysis method is the melt index (Melt Index), and the unit is g / 10min. When the melt flow index is less than 1, the time required for the reaction is prolonged due to reduced fluidity, and when it is greater than 10, the elasticity and restoring force are reduced.

[0077] The purpose of the olefin elastomer of the present invention may be to maintain the melt strength of the resin during the foaming of the resin composition. At this time, the Mooney viscosity of the olefin elastomer is 25 to 75 based on 125°C. Mooney viscosity is a value indicating the viscosity of rubber, which affects the processability of the rubber and the physical properties of the rubber after vulcanization. By providing an olefin elastomer that satisfies the above range, the problem of reduced foaming processability due to high melt strength during foaming can be prevented, and excellent flexibility and processability can be provided.

[0078] According to an embodiment of the present invention, based on ASTM D1238, the melt index (MI) of the olefin elastomer is 0.1-30 g / 10 min at 190° C. and 2.16 kg, and the weight average molecular weight of the olefin elastomer is 10,000-800,000 g / mol.

[0079] According to one embodiment of the present invention, the olefin elastomer comprises a 20 At least one of α-olefin and ethylene-propylene copolymer rubber. 20 The α-olefin may be preferably ethylene, and in this case, 40 to 90 wt% of ethylene may be contained. When 40 to 90 wt% of ethylene is contained, a suitable hard segment can be provided, thereby providing excellent strength and molding processability.

[0080] According to an embodiment of the present invention, the ethylene-propylene copolymer rubber may include at least one selected from ethylene propylene rubber (EPR) and ethylene propylene diene monomer rubber (EPDM), and ethylene propylene diene monomer rubber (EPDM) may be preferred.

[0081] According to an embodiment of the present invention, the ethylene propylene diene monomer (EPDM) rubber comprises ethylene, propylene and ethylidene norbornene (ENB), and in this case, comprises 40-80 wt % of ethylene, 10-50 wt % of propylene and 0.5-10 wt % of ethylidene norbornene.

[0082] According to one embodiment of the present invention, a foaming resin composition is provided, which comprises 0.1 to 10 parts by weight of a silica nucleating agent, 0.1 to 5 parts by weight of a cross-linking agent, 1 to 20 parts by weight of a foaming agent and 1 to 10 parts by weight of a foaming aid relative to 100 parts by weight of the blended resin.

[0083] In more detail, the blended resin may contain 80 to 20 parts by weight of olefin elastomer relative to 20 to 80 parts by weight of ethylene-vinyl acetate copolymer (EVA), and preferably contain 60 to 40 parts by weight of ethylene-vinyl acetate copolymer (EPDM) relative to 40 to 60 parts by weight, so that the foam can be fully foamed and can provide the foaming composition with excellent elasticity and restoring force.

[0084] In particular, according to one embodiment of the present invention, 0.1 to 10 parts by weight of a silica nucleating agent may be included relative to 100 parts by weight of the blended resin, and 0.1 to 5 parts by weight may be preferably included. In view of the results of Table 2 of the embodiments described later, it can be confirmed that the overall physical properties of phylon prepared from a foaming composition containing 0.1 to 5 parts by weight of a silica nucleating agent are improved. In particular, in view of the split tear strength (STS), resilience, and energy loss coefficient, excellent wear resistance and impact resistance can be expected, and in view of the hardness and density values, excellent lightness can be expected.

[0085] According to one embodiment of the present invention, the silica nucleating agent includes at least one selected from fumed silica, fused silica, precipitated silica, silica gel, colloidal silica and crystalline silica, and fumed silica is preferred. In view of the results of Table 2 of the embodiments described later, when a nano-sized silica nucleating agent is provided, excellent physical properties can be provided when the foaming composition forms a foam, and in particular, a foaming composition having excellent split tear strength (STS) and resilience and excellent hardness can be provided.

[0086] According to one embodiment of the present invention, the average particle size of the silica nucleating agent is in the range of 1 to 50 nm, preferably in the range of 7 to 40 nm.

[0087] Generally, the smaller the particle size of the nucleating agent, the larger the specific surface area (BET), and the larger the specific surface area, the stronger the nucleating effect, thereby generating more microbubbles. When uniform microbubbles are generated, the mechanical properties of the foam during foaming can be improved. Therefore, in order to form uniform microbubbles, a silica nucleating agent of 7 to 40 nm can be provided to change the cell morphology, thereby forming microbubbles and improving the mechanical properties of the foam. When it is less than 7 nm, the specific surface area increases and the surface energy increases, which will lead to condensation of SiO2. When it is greater than 40 nm, it is difficult to provide uniform microbubbles, so the above range is preferred. In view of the results of Table 2 described later, it can be confirmed that the mechanical property values ​​of the foam are improved according to the size of the nucleating agent.

[0088] According to one embodiment of the present invention, the cross-linking agent may be an organic peroxide, and may be a dialkyl organic peroxide, for example, it may be at least one selected from 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butyl isopropyl peroxide, diisopropyl peroxide (DCP), 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,3-bis(tert-butylperoxyisopropyl)benzene, and diisopropyl peroxide (DCP) may be preferred.

[0089] In particular, the peroxide contained in the organic peroxide is activated to provide a site for extracting hydrogen atoms from the polymer skeleton and cross-linking, thereby initiating a cross-linking process. In this way, the foam is cross-linked during the foaming process, so that a foamed molded product with improved physical properties can be provided. In particular, the cross-linking agent can impart the preferred viscoelasticity required for foaming. In addition, in order to perform cross-linked foaming, it is preferred that ethylene-vinyl acetate copolymer (EVA) is first cross-linked by decomposition of the cross-linking agent to obtain appropriate viscoelasticity, and then the foaming agent is decomposed to form bubbles. The expansion ratio is basically determined by the amount of the foaming agent added, and the elasticity of the ethylene-vinyl acetate copolymer (EVA) has a greater relationship with the formation of bubbles. Therefore, when 0.1 to 5 parts by weight of the cross-linking agent is included relative to 100 parts by weight of the blended resin, satisfactory physical properties of the final product can be provided.

[0090] According to one embodiment of the present invention, the foaming agent is an additive for making bubbles contained in a resin such as rubber or plastic, and the chemical foaming agent may provide an organic foaming agent. For example, the organic foaming agent may include at least one selected from azodicarbonamide, dinitrosopentamethylenetetramine, and P,P'-oxybisbenzenesulfonylhydrazine, preferably azodicarbonamide, and may also be a denatured azodicarbonamide. For example, JTR-M that can be obtained through commercial channels may be provided.

[0091] In addition, 1 to 20 parts by weight of a foaming agent may be included relative to 100 parts by weight of the blended resin, thereby providing physical properties such as lightness, cushioning, and heat insulation. In particular, when applied to shoemaking materials, it can provide the function of absorbing the impact that occurs during intense exercise or walking. In addition, when the decomposition temperature is less than 130°C, the foaming agent has the problem of foaming in the initial stage of the reaction, and when it is greater than 200°C, the foaming time is too long, and there is a problem with productivity. Therefore, the range of 130°C to 200°C is preferred.

[0092] According to one embodiment of the present invention, the foaming aid is a metal oxide, which may include at least one selected from zinc oxide, calcium oxide, magnesium oxide, tin oxide, cadmium oxide and lead oxide, and zinc oxide may be preferred. Relative to 100 parts by weight of the blended resin, 1 to 10 parts by weight of the foaming aid may be included to adjust the foaming speed of the resin composition, increase the foaming rate, and adjust the foaming density inside the foaming layer. For example, B-50ZnO from BUWON may be provided.

[0093] According to one embodiment of the present invention, in addition to the foaming agent and the foaming aid, a bubble generation promoter and a surfactant may be further added to affect the generation of bubbles in the resin. In addition, at least one selected from a stabilizer, an antioxidant, a filler and a colorant may be included as needed to adjust the physical properties, but is not limited thereto.

[0094] According to one embodiment of the present invention, a material comprising a foaming resin composition is provided. The material can be applied to electronic component materials, mechanical parts materials, automotive parts materials, construction materials, packaging materials, etc., and is preferably used for shoemaking materials. It can be used for midsoles and insoles that require ultra-lightweight, and can also be used for uppers and outsoles that require wear resistance and impact absorption, and can also be used for heels, slipper soles, etc., but is not limited thereto.

[0095] On the other hand, according to one embodiment of the present invention, there is provided a method for preparing a foaming resin composition, the method comprising the following steps: step (a), preparing a blended resin comprising ethylene-vinyl acetate copolymer (EVA) and an olefin elastomer resin; step (b), adding a silica nucleating agent to the blended resin, and kneading for the first time; step (c), adding a crosslinking agent, a foaming agent and a foaming aid to the blended resin, and kneading for the second time. At this time, the preparation method is a melt blending method. Below, the composition included in the preparation method can be applied to the same content as the aforementioned resin composition and proportion, and repeated description is omitted.

[0096] According to one embodiment of the present invention, in the step (a), the blended resin comprises 20 to 80 parts by weight of an olefin elastomer relative to 20 to 80 parts by weight of ethylene-vinyl acetate copolymer (EVA). In addition, the olefin elastomer may comprise a C2 to C 20At least one of α-olefin and ethylene-propylene copolymer rubber. In this case, the ethylene-propylene copolymer may be included. With respect to 40 to 60 parts by weight of the ethylene-vinyl acetate copolymer (EVA), 60 to 40 parts by weight of ethylene-propylene diene monomer rubber (EPDM) is preferably included. In this case, 40 to 80% by weight of ethylene, 10 to 50% by weight of propylene and 0.5 to 10% by weight of ethylidene norbornene are included.

[0097] According to one embodiment of the present invention, in the step (b), 0.1 to 10 parts by weight of a silica nucleating agent is included relative to 100 parts by weight of the blended resin, and the average particle size of the silica nucleating agent is 1 to 50 nm, preferably 7 to 40 nm. The description of the content and size of the silica nucleating agent is the same as the above content.

[0098] According to one embodiment of the present invention, in the step (b), the step of adding the silica nucleating agent and performing the first kneading can be performed at 100° C. to 150° C., preferably 100° C. to 110° C., and preferably the non-reactive nucleating agent is added before other additive compositions.

[0099] According to one embodiment of the present invention, in the step (c), 0.1 to 5 parts by weight of a crosslinking agent, 1 to 20 parts by weight of a foaming agent and 1 to 10 parts by weight of a foaming aid are included relative to 100 parts by weight of the blended resin, and a second kneading step is performed. The temperature is the same as that of step (b), and can be performed for 5 to 15 minutes.

[0100] According to one embodiment of the present invention, melt blending refers to heating the polymer material to be blended to a temperature above its melting point to melt it, and then using mechanical force to prepare a new substance. In the present invention, the resin can be compressed after being melted at its melting point.

[0101] According to an embodiment of the present invention, the melt blending method may use at least one selected from an extruder, a kneader, a Brabender plasticizer, a mixing roll and a mixer.

[0102] According to one embodiment of the present invention, the extruder is preferably a melt extruder, which can optimize the process conditions according to the various raw materials input in the melting process and implement the process. In the melting process, the melting temperature can be 100°C to 300°C, preferably 150°C to 230°C. At this time, the melt flow index can be 0.1 to 60, and the viscosity analysis method is the melt index (Melt Index), and the unit is g / 10min.

[0103] According to one embodiment of the present invention, the extruder may be any one selected from a uniaxial extruder, a biaxial extruder, a single screw extruder and a biaxial extruder, and a biaxial extruder may be preferred.

Claims

1. A foaming resin composition, characterized in that The invention relates to 100 parts by weight of the blended resin, comprising 0.3 to 3 parts by weight of a silica nucleating agent, 0.1 to 5 parts by weight of a crosslinking agent, 1 to 20 parts by weight of a foaming agent and 1 to 10 parts by weight of a foaming aid. The blended resin contains 80 to 20 parts by weight of olefin elastomer relative to 20 to 80 parts by weight of ethylene-vinyl acetate copolymer. The average particle size of the silica nucleating agent is 7 to 40 nm.

2. The foaming resin composition according to claim 1, characterized in that The blended resin contains 60 to 40 parts by weight of ethylene-vinyl acetate copolymer relative to 40 to 60 parts by weight of ethylene-propylene-diene monomer rubber.

3. The foaming resin composition according to claim 1, characterized in that The olefin elastomer comprises a member selected from C2 to C 20 At least one of α-olefin and ethylene-propylene copolymer rubber.

4. The foaming resin composition according to claim 3, characterized in that The ethylene-propylene copolymer rubber includes at least one selected from ethylene-propylene rubber and ethylene-propylene-diene monomer rubber.

5. The foaming resin composition according to claim 4, characterized in that The EPDM rubber contains 40 to 80 weight percent of ethylene, 10 to 50 weight percent of propylene and 0.5 to 10 weight percent of ethylidene norbornene.

6. The foaming resin composition according to claim 1, characterized in that The Mooney viscosity of the olefin elastomer is 10-100 based on 125°C.

7. The foaming resin composition according to claim 1, characterized in that The silica nucleating agent includes at least one selected from fumed silica, fused quartz, precipitated silica, silica gel, silica sol, and crystalline silica.

8. The foaming resin composition according to claim 1, characterized in that The crosslinking agent includes at least one selected from 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butyl isopropyl peroxide, diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,3-bis(tert-butylperoxyisopropyl)benzene.

9. The foaming resin composition according to claim 1, characterized in that The foaming agent includes at least one selected from azodicarbonamide, dinitrosopentamethylenetetramine, and P,P'-oxybisbenzenesulfonylhydrazide.

10. The foaming resin composition according to claim 1, characterized in that The foaming aid includes at least one selected from zinc oxide, calcium oxide, magnesium oxide, tin oxide, cadmium oxide and lead oxide.

11. A material comprising a foaming resin composition, characterized in that ， The foaming resin composition according to any one of claims 1 to 10 is included.

12. The material comprising a foaming resin composition according to claim 11, characterized in that: The material can be applied to at least one selected from electronic component materials, mechanical parts materials, automobile parts materials, building materials, packaging materials and shoemaking materials.

13. A method for preparing a foaming resin composition, characterized in that: The following steps are involved: Step (a), preparing a blended resin comprising ethylene-vinyl acetate copolymer and an olefin elastomer; Step (b), adding a silica nucleating agent to the blended resin and performing a first kneading; and Step (c), adding a crosslinking agent, a foaming agent and a foaming aid to the blended resin, and kneading for a second time, Wherein, in the step (b), 0.3 to 3 parts by weight of a silica nucleating agent is included relative to 100 parts by weight of the blended resin. In the blended resin of step (a), 20 to 80 parts by weight of ethylene-vinyl acetate copolymer is included, and 20 to 80 parts by weight of olefin elastomer is included. In the step (b), the average particle size of the silica nucleating agent is 7 to 40 nm.

14. The method for preparing a foaming resin composition according to claim 13, characterized in that: The step (b) is carried out at 100°C to 150°C.

15. The method for preparing a foaming resin composition according to claim 13, characterized in that: In the step (c), relative to 100 parts by weight of the blended resin, 0.1 to 5 parts by weight of a cross-linking agent, 1 to 20 parts by weight of a foaming agent and 1 to 10 parts by weight of a foaming aid are included.

16. The method for preparing a foaming resin composition according to claim 13, characterized in that: The preparation method adopts a melt blending method, using at least one selected from an extruder, a kneader, a Brabender plasticizer, a mixer and a mixer.

Images