KR101928925B1 - Polyolefin foam particle with excellent impact resistance - Google Patents

Abstract

The present invention relates to polyolefin foam particles with excellent impact resistance and a method for producing the same. More particularly, the present invention relates to foam particles with excellent elasticity and excellent tensile strength and elongation by mixing a polyolefin elastomer resin with a polyolefin resin, and a method for producing the same. The polyolefin foam particles according to one embodiment of the present invention comprise a base resin composition in which the polyolefin elastomer resin is mixed with the polyolefin resin. When temperature is raised from 0 ° C to 200 ° C at a heating rate of 10 ° C/min by heat flux differential scanning calorimetry, three endothermic peaks appear. 90% or more of independent foam cells having a cross-sectional diameter of 10 to 300 μmm are formed. The polyolefin foam particles have a bulk density of 15 to 500 g/L.

Description

[0001] The present invention relates to a polyolefin foam particle having excellent impact resistance,

The present invention relates to polyolefin-based expanded particles excellent in impact resistance and a method for producing the same, and more particularly, to polyolefin-based expanded particles excellent in elasticity, excellent in tensile strength and elongation, And a manufacturing method thereof.

Existing polyolefin particle foams are foamed polypropylene foam (EPP) or foamed polyethylene (EPE), and they are used as a shock absorber for automobiles and packaging materials for electronic products.

However, in the case of a molded article using EPP particles, it has excellent strength and resilience against repeated compression. However, it is vulnerable to impact and easily cracks or tears. Since the surface hardness of the molded article is high, a feeling of comfort or soft properties is required Products have limited use.

EPE has excellent impact resistance and elongation compared to EPP, and is soft. However, the EPE does not recover quickly from deformation due to impact, and is weak in rebound resilience and is not suitable as a shock absorber.

The present invention provides a foamed polyolefin particle having excellent strength and excellent resilience against repeated compression, and excellent in elasticity and softness, and a method for producing the same.

The polyolefin-based expanded bead according to an embodiment of the present invention comprises a base resin composition in which a polyolefin-based elastomer resin is mixed with a polyolefin-based resin, and is heated at a temperature raising rate of 10 占 폚 / min at 200 占 폚 Deg.] C, 90% or more of closed cell having a cross-sectional diameter of 10 to 300 mu m is formed, and a bulk density of 15 to 500 g / L is characterized.

The expanded particles have an endothermic peak at a high temperature endothermic peak in the endothermic peak of 0.1 to 20 cal / g.

The expanded particles are characterized by having a bubble cell having a diameter of 150 to 300 탆 of 60% or more and a bulk density of 15 to 250 g / L.

Wherein the polyolefin-based resin has a density of 870 to 930 g / L and is selected from the group consisting of resins having a melt index (MI) of 0.1 to 100 g / 10 min (210 DEG C / 2.16 kg) .

Wherein the polyolefin resin is a resin selected from a propylene homopolymer, a propylene random copolymer, a propylene block copolymer, a propylene graft copolymer, a polyethylene, and an ethylene vinyl acetate copolymer, and a mixture thereof.

Wherein the polyolefin elastomer resin is a resin selected from the group consisting of resins having a density of 860 to 900 g / L and a melt index (MI) of 0.1 to 50 g / 10 min (190 DEG C / 2.16 kg) And mixtures thereof.

Wherein the polyolefin-based elastomer resin is selected from the group consisting of copolymers of? -Olefins selected from? -Olefins of C ₂ to C ₂₀ , or a mixture thereof.

Wherein the polyolefin-based elastomer resin is a resin selected from the group consisting of resins having a shore A hardness of 40 to 90 or a mixture thereof.

The base resin composition further comprises at least one additive selected from the group consisting of an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant, a metal deactivator, a pigment, a dye, a nucleating agent, a crosslinking agent, and a foam modifier.

On the other hand, a method for producing a polyolefin-based expanded particle according to an embodiment of the present invention comprises preparing a base resin composition in which a polyolefin-based resin and a polyolefin-based elastomer resin are mixed, extruding the prepared base resin composition, A resin particle preparation step of producing a resin particle of a shape; And a foaming step of mixing the foaming agent with the resin particles and then foaming to produce expanded particles.

The weight ratio of the polyolefin-based resin to the polyolefin-based elastomer resin in the resin particle preparation step is 8: 2 to 5: 5.

In the resin particle preparation step, the base resin composition contains 0.001 to 5 parts by weight, based on 100 parts by weight of the total amount of the polyolefin resin and the polyolefin elastomer resin, as a foam modifier as an additive.

In the resin particle preparation step, the base resin composition may contain at least one additive selected from the group consisting of an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant, a metal deactivator, a pigment, a dye, a nucleating agent, a crosslinking agent, 0.001 to 10 parts by weight based on 100 parts by weight of the total of the resin and the polyolefin-based elastomer resin.

In the resin particle preparation step, the base resin composition is put into an extruder, kneaded at 150 to 230 ° C, extruded into a strand shape, cooled, and then cut into pellets.

Wherein the polyolefin-based elastomer resin contained in the base resin composition in the resin particle preparation step is a single copolymer or a mixture thereof selected from the group consisting of copolymers of? -Olefins selected from? -Olefins of C ₂ to C ₂₀ .

In the resin particle preparation step, the base resin composition further comprises a polyolefin-based polymer, wherein the polyolefin-based polymer is a copolymer of a polyolefin-based homopolymer and a polyolefin-based resin and an? -Olefin selected from a C ₂ to C ₂₀ ? Copolymers, and mixtures thereof.

Wherein the foaming step is carried out by adding a solvent, a surfactant, and a dispersant to the resin particles and then stirring while heating. When the heating temperature reaches the foaming temperature range, a foaming agent is added and the foaming temperature range And discharging it under atmospheric pressure to foam the resin particles to produce expanded particles.

The foaming temperature range is 120 to 170 ° C, and the foaming pressure range is 10 to 50 bar.

According to the embodiment of the present invention, it is possible to produce foamed particles having excellent foam properties, tensile strength, elongation and elasticity as compared with conventional polyolefin-based foamed resins, and to provide such foamed particles with elasticity, repeated compression and permanent compression There is an effect that it can widely be applied to a member requiring an excellent restoring force.

In addition, the molded article obtained from the foamed particles according to the present invention provides an excellent tensile strength and tensile strength over conventional polyolefin-based foamed molded articles, and can provide excellent flexibility without tearing when torsion or bending occurs.

The base resin composition in which the polyolefin-based elastomer resin is mixed with the polyolefin-based resin is excellent in the foaming property, so that it is easy to adjust the expansion ratio as necessary. The low-expansion foam has excellent softness and high softness It is possible to produce excellent expanded particles and a molded body thereof.

In addition, the expanded particles according to the present invention have a high ratio of independent pores, so that excellent environmental resistance such as excellent compression strength, chemical resistance, and water resistance can be expected.

FIG. 1 is a graph showing an endothermic peak heat quantity in a DSC curve of a foamed particle according to an embodiment of the present invention, and FIG.
2 is a cross-sectional SEM photograph of expanded particles according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know.

The polyolefin-based expanded beads according to one embodiment of the present invention are spherical or cylindrical bead-shaped foams formed by incorporating a base resin composition in which a polyolefin-based elastomer resin excellent in impact resistance is mixed into a polyolefin-based resin, It has excellent elasticity and excellent durability against repeated impact.

Meanwhile, FIG. 1 is a graph showing an endothermic peak heat quantity in a DSC curve of a foamed particle according to an embodiment of the present invention.

1, there are shown three endothermic peaks, the polyolefin elastomer resin has a peak of heat of fusion between 80 and 100 ° C, and the polyolefin resin has two endothermic peaks at 100-140 ° C and 140-160 ° C Can be seen. The foam of the polyolefin resin has a non-crystalline heat absorption peak and a crystalline heat absorption peak, and the endothermic peak at the low temperature portion is non-crystalline and is highly influential to the meltability. The endothermic peak at the high temperature portion, .

As can be seen from Fig. 1, the expanded particles exhibit three endothermic peaks in the DSC curve obtained when the temperature of the expanded particles is raised from 0 ° C to 200 ° C at a heating rate of 10 ° C / min by measurement of heat flux differential scanning calorimetry. Particularly, the expanded particles have an endothermic peak at a high temperature endothermic peak in the endothermic peak of 0.1 to 20 cal / g. Preferably, the endothermic peak of the high temperature endothermic peak in the endothermic peak is 0.5 to 5 cal / g

Here, in the DSC curve of the expanded particles, the primary and secondary endothermic peaks on the low-temperature side can be seen to be attributed to the endotherm of the polyolefin-based resin and the polyolefin-based elastomer resin constituting the expanded particles upon melting. The endothermic peak appearing on the higher temperature side than the endothermic peak on the low temperature side can be regarded as the endothermic peak due to the crystal structure formed in the polyolefinic resin due to the bead foam process. When the foamed molded article is molded using the expanded particles, the endothermic peak on the low-temperature side affects the fusion-bondability between the expanded particles, and the endothermic peak on the high-temperature side fills the pores between the expanded particles with respect to the secondary expansion property of the expanded particles, The expanded particles are not shrunk even when a high steam pressure is added, which is an important factor for securing the moldability of the expanded molded article. Therefore, the above-mentioned expanded particles are excellent in fusion-bonding property, exhibit the property of imparting secondary extensibility during molding of the expanded molded article, and have excellent appearance characteristics such as small porosity between the expanded particles without finding a depressed part on the surface of the expanded molded article Lt; / RTI >

2 is a cross-sectional SEM photograph of expanded particles according to an embodiment of the present invention.

As can be seen in FIG. 2, the expanded particles are formed as a fine closed pore cell. At this time, the expanded particles have more than 90% of independent bubble cells having a cross-sectional diameter of 10 to 300 mu m. The size of each independent bubble cell can be adjusted depending on the content and kind of the additive. In order to obtain excellent appearance and foaming performance when forming the foamed particles, more than 60% of bubble cells having a diameter of 150 to 300 μm are formed .

And the expanded particles have a bulk density of 15 to 500 g / L. Preferably, the expanded particles have a bulk density of 15 to 250 g / L.

A method for producing the polyolefin-based expanded beads according to one embodiment of the present invention having the above-described characteristics will be described.

The method for producing a polyolefin-based expanded bead according to an embodiment of the present invention comprises preparing a base resin composition in which a polyolefin-based resin and a polyolefin-based elastomer resin are mixed, extruding the prepared base resin composition, cooling and cutting the pellet- A resin particle preparation step of producing resin particles; And a foaming step of mixing the foaming agent with the resin particles and then foaming to produce expanded particles.

First, in the resin particle preparation step, a base resin composition in which a polyolefin-based elastomer resin is mixed with a polyolefin-based resin is prepared.

Here, the polyolefin-based resin contained in the base resin composition is composed of resins having a density of 860 to 930 g / L and a melt index (MI) of 0.1 to 100 g / 10 min (210 DEG C / 2.16 kg) , Or a mixture thereof. For example, the polyolefin resin may be a resin selected from a propylene homopolymer, a propylene random copolymer, a propylene block copolymer, a propylene graft copolymer, a polyethylene, and an ethylene vinyl acetate copolymer, and a mixture thereof.

The polyolefin-based elastomer resin contained in the base resin composition has a density of 860 to 900 g / L and is made of resins having a melt index (MI) of 0.1 to 50 g / 10 min (190 DEG C / 2.16 kg) , Or a mixture thereof. For example, the polyolefin-based elastomer resin may be a single copolymer or a mixture thereof selected from the group consisting of copolymers of? -Olefins selected from? -Olefins of C2 to C20. Specific examples of the? -Olefin include ethylene, 1-butene, 1-pentene, 1-hexene, and the like, but the present invention is not limited thereto.

The polyolefin elastomer resin may be a resin selected from the group consisting of resins having a shore A hardness of 40 to 90, or a mixture thereof.

On the other hand, the base resin composition may further include at least one additive selected from the group consisting of an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant, a metal deactivator, a pigment, a dye, a nucleating agent, a crosslinking agent and a foam modifier.

Preferably, fine particles of an inorganic material may be used as the bubble adjusting agent, and Talc, CaCO ₃ or ZnB may be preferably used as the additive. The foam modifier may be selected from resins having a high heat-resistant temperature, and preferably, PTFE may also be used, but is not limited thereto.

In addition, carbon black or a pigment may be mixed for coloring purposes, and in addition to the colorant, an antistatic agent that imparts conductivity to the composition and a pigment that color the composition may be mixed.

The additive may include 0.001 to 10 parts by weight based on 100 parts by weight of the total of the polyolefin resin and the polyolefin elastomer resin. If the additive is contained in an amount of less than 0.001 part by weight, it may be difficult to achieve the purpose of adding the additive. In the case of carbon black, antistatic effect and coloring effect may be insufficient. When the additive is contained in an amount exceeding 10 parts by weight, It may have an influence on the physical properties, and the increase of the effect is not efficient compared with the increase of the addition amount. Particularly, it is preferable that 0.001 to 5 parts by weight, based on 100 parts by weight of the polyolefin-based elastomer resin and the polyolefin-based elastomer resin, is added as an additive to maintain foamability of the expanded particles.

On the other hand, in the resin particle preparing step, the polyolefin-based resin and the polyolefin-based elastomer resin are preferably mixed in a weight ratio of 8: 2 to 5: 5.

When the weight ratio of the polyolefin-based resin in the polyolefin-based elastomer resin to the polyolefin-based resin in the resin particle preparation step exceeds 8, the elasticity property of the polyolefin-based elastomer is not exhibited and the weight ratio of the polyolefin- If it is less than 5, the whole physical properties are too weak to easily cause shrinkage.

When the base resin composition is prepared as described above, the prepared base resin composition is put into an extruder, and the mixture is melted and kneaded by heating at 150 to 230 ° C. Then, it is extruded in a strand shape, cooled and then cut or cut while being cooled in water immediately after extrusion to produce resin pellet-shaped resin pellets called mini pellets.

In this case, the pellet-shaped resin particles may have an average weight of 0.5 to 50 mg per resin particle and a length / diameter ratio (L / D) of 0.1 to 4.

The resin particles having a weight and a length / diameter ratio are effective for obtaining uniform expanded particles upon foaming, and foamed particles can be uniformly filled into the mold using foamed particles, which is effective for producing a molded article.

On the other hand, in the foaming step, foaming agent is added to the resin particles produced in the resin particle preparation step to foam the resin particles to obtain expanded particles.

Specifically, in the foaming step, a solvent, a surfactant, and a dispersant are added together with the resin particles into a vaporizer, followed by stirring while heating. Water may be used as the solvent. The surfactant and the dispersant serve to uniformly disperse the resin particles in the solvent. Preferably, sodium alkanesulfonate may be used as the surfactant, and calcium tertiary phosphate or kaolin powder may be used as the dispersing agent. However, But is not limited thereto.

When the resin particles in the foaming machine and the solvent, the surfactant and the dispersing agent are heated and stirred while the temperature in the foaming machine is heated to a temperature higher than the foaming temperature range, that is, the glass transition temperature of the resin particles, the foaming agent is added and mixed. At this time, the foaming agent serves to foam the composition containing the resin particles, and preferably carbon dioxide, butane, or pentane gas may be used, but the present invention is not limited thereto.

When the temperature in the foaming apparatus reaches the foaming temperature range, the composition containing the resin particles mixed with the foaming agent is discharged into a low-pressure region, for example, an atmospheric pressure atmosphere while maintaining a high-pressure foaming pressure range, After cooling, it is washed and dried to obtain expanded particles. At this time, the density of the expanded particles can be controlled by controlling the temperature and the pressure of the reactor or the amount of the blowing agent, and preferably the foaming temperature ranges from 120 to 170 ° C and the foaming pressure ranges from 10 to 50 bar. The thus obtained expanded particles have a density of 15 to 500 g / l.

The foamed particles produced by this foaming step exhibit three endothermic peaks when measured while heating from 0 ° C to 200 ° C at a heating rate of 10 ° C / min using a thermal analyzer (Differential Scanning Calorimeter). Preferably, the heat absorption amount of the high temperature endothermic peak among the three endothermic peaks may be 0.1 to 20 cal / g. Preferably, the heat absorption amount of the high-temperature endothermic peak among the three endothermic peaks may be 0.5 to 5 cal / g

In the case of expanded particles having an endothermic peak at a high temperature endothermic peak of 0.1 to 20 cal / g in the above-mentioned three endothermic peaks, the fusion of the expanded particles smoothly occurs even at a low temperature in the production of the expanded molded article.

When the expanded particles are produced by the above-mentioned method, an expanded molded article can be produced using the expanded particles.

When the expanded particles are produced by the above-mentioned method, an expanded molded article can be produced using the expanded particles.

The foamed molded article produced from the expanded particles manufactured according to the present invention is soft, has excellent elasticity, and is easily restored to external stress for a long period of time because of a small strain due to permanent compression, and has excellent buffering ability to absorb external impact.

At this time, the method for producing the expanded molded article using the expanded particles produced according to the present invention can be obtained by a general method known in the art, and the production method thereof is not limited to the specific method.

For example, a method for producing an expanded molded article using the expanded particles produced according to the present invention is characterized in that the prepared expanded particles are first placed in a closed container, then pressure is applied by air to form an internal pressure, Steam is supplied to expand the expanded particles. Then, it is cooled and taken out of the mold to obtain an expanded molded article.

The foamed molded article thus obtained is aged at a temperature between 60 and 90 ° C for a certain period of time according to the density to remove water contained in the cooling step of the foamed molded article to restore the shrunk part of the product.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. It is to be understood that the present invention is not limited by the scope of the present invention.

1. Preparation of pellet-shaped resin particles (resin particle preparation step)

First, the base resin composition according to Examples and Comparative Examples having the compositions and contents shown in Table 1 were put into an extruder, and the mixture was sufficiently kneaded by an extruder while heating at 150 to 230 캜. The kneaded base resin composition was extruded into a strand shape, cooled in water and cut into a cylindrical shape with a pelletizer to produce resin particles in the form of mini-pellets.

The polyolefin resin used herein was an ethylene-propylene-butene-terpolymer having a melting point of 135 ° C and a melt index (MI) of 6 g / 10 min (210 ° C, 2.16 kg) as measured by ASTM D1238, Is 7,500 kg / cm ² .

The polyolefin elastomer resin has a melting point of 96 占 폚, a melt index (MI Index) measured by ASTM D1238 of 1.2 g / 10 min (190 占 폚, 2.16 kg), and an A shore hardness of 91.

As additives, PTFE, ZnB and / or Talc, which are foam modifiers, were used, and carbon black was used as a colorant.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Polyolefin 70 60 0 100 80 50 Polyolefin
Elastomer 30 40 100 0 20 50 PTFE (phr) 0.2 0.2 0.2 0.2 0.2 0.2 ZnB (phr) 0.2 0.02 0.2 0.2 0.2 0.2 Talc (phr) 0.1 0.1 0.1 0.1 0.1 0.1 Carbon black (phr) - - - - - 5

2. Preparation of expanded particles (foaming step)

Water, a surfactant, and a dispersant as a solvent were added to the reactor together with the resin particles obtained in the resin particle preparation step in the composition shown in Table 2, and the mixture was heated with stirring. When the temperature of the contents reached the foaming temperature range shown in Table 2 below, carbon dioxide was introduced as a blowing agent to maintain a high pressure state. Subsequently, the temperature inside the reactor was heated to maintain the foaming temperature shown in Table 2, and the discharging nozzle of the reactor was opened to release the contents in the reactor under atmospheric pressure to foam the resin particles in mini pellet form to prepare expanded particles.

In addition, carbon dioxide was continuously supplied into the reactor during the discharge to keep the pressure in the reactor constant during discharge. Thereafter, the expanded particles were washed and dehydrated, and then dried at atmospheric pressure for 8 hours or more. The peak temperature of the foamed particles was measured, and the results are shown in Table 2.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Mini Pellets 24 24 24 24 24 24 water 76 76 76 76 76 76 Surfactant (phr) 0.19 0.19 0.19 0.19 0.19 0.19 Kaolin (phr) 0.16 0.16 0.16 0.16 0.16 0.16 Foaming temperature (캜) 150 150 150 150 150 150 Reactor pressure (bar) 40 40 40 40 40 40 Desnity (g / L) 37 36 200 37 135 121 DSC Secondary (cal / g) 4 3.9 4.1 4.1 3.8 3.9 Foaming Good Good Bad Good Bad Bad

3. Manufacture of expanded molded article

The expanded particles obtained in Examples 1 and 2 and Comparative Examples 1 to 4 are dried naturally or using a heat source. Then, the expanded particles were filled in a mold having a cavity size of 25 cm x 10 cm x 3 cm and passed through saturated steam to heat the expanded particles, followed by cooling to obtain an expanded molded article. The obtained expanded molded article is cured in an atmosphere at 40 to 80 캜 for 4 hours and then left at room temperature for 2 hours to obtain an expanded molded article.

4. Evaluation of impact resistance test of expanded molded article

The impact resistance test of the foamed molded article was carried out in the same manner as in Examples 1 and 2 and Comparative Examples 1 to 4 except that the expanded molded article was made into a test piece having a size of 100 mm x 100 mm and a size of 50 mm or more and then a test piece having a diameter of 63 mm and a weight of 20 kg The branching weight was dropped at a height of 2000 mm and the impact resistance was measured. The results are shown in Table 3.

At this time, evaluation of product shape, shrinkage, cracks, surface tearing and surface cracking was visually checked to determine the presence of defects.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Product shape OK OK NG OK OK OK Contraction OK OK NG OK OK NG crack OK OK OK NG NG OK Surface tear OK OK OK NG OK OK Surface cracking OK OK OK NG NG OK Restoration state after impact OK OK OK NG OK OK

As can be seen from Table 3, in Examples 1 and 2, the appearance of the product was excellent due to the proper amount of the polyolefin resin and the polyolefin elastomer resin, and the impact evaluation result was restored without tearing or cracking.

However, in the case of Comparative Examples 1 and 4, it was confirmed that the shrinkage in the step of preparing the expanded particles and the resultant product shape were difficult to realize in the production of the molded article.

In the case of Comparative Example 2, it was confirmed that cracking and cracking occurred in the appearance of the product during the evaluation of the impact resistance test, although the foamed particle production and moldability were excellent, but the strength was high.

In Comparative Example 3, it was confirmed that the content of the polyolefin elastomer was too high to cause excessive shrinkage, and that it was not suitable for the production of expanded particles.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

Claims (18)

A base resin composition comprising a polyolefin-based resin and a polyolefin-based elastomer resin mixed therein,
When the temperature was raised from 0 ° C to 200 ° C at a heating rate of 10 ° C / min by heat flux differential scanning calorimetry, three endothermic peaks appeared,
The peak temperature of the endothermic peak of the three endothermic peaks is in the range of 140 to 160 ° C,
The endothermic peak at the highest temperature among the three endothermic peaks exhibits a larger endothermic value than the other endothermic peak,
90% or more of independent bubble cells having a cross-sectional diameter of 10 to 300 mu m are formed,
A polyolefin-based expanded particle having a bulk density of 15 to 500 g / L.
The method according to claim 1,
The peak temperatures of the three endothermic peaks of the expanded particles appear in a range of 80 to 100 ° C, a range of 100 to 140 ° C and a range of 140 to 160 ° C,
Wherein an endothermic peak at a high temperature endothermic peak at an apex temperature of the endothermic peak in the range of 140 to 160 占 폚 in the endothermic peak is 0.1 to 20 cal / g.
The method according to claim 1,
Wherein the expanded particles have a bubble cell having a diameter of 150 to 300 탆 of 60% or more and a bulk density of 15 to 250 g / L.
The method according to claim 1,
Wherein the polyolefin-based resin has a density of 870 to 930 g / L and is selected from the group consisting of resins having a melt index (MI) of 0.1 to 100 g / 10 min (210 DEG C / 2.16 kg) Based on the total weight of the polyolefin-based expanded particles.
The method according to claim 1,
Wherein the polyolefin resin is a resin selected from a propylene homopolymer, a propylene random copolymer, a propylene block copolymer, a propylene graft copolymer, a polyethylene, and an ethylene vinyl acetate copolymer, and a mixture thereof.
The method according to claim 1,
Wherein the polyolefin elastomer resin is a resin selected from the group consisting of resins having a density of 860 to 900 g / L and a melt index (MI) of 0.1 to 50 g / 10 min (190 DEG C / 2.16 kg) Based on the total weight of the polyolefin-based expanded particles.
The method according to claim 1,
Wherein the polyolefin-based elastomer resin is a copolymer of? -Olefins selected from? -Olefins of C ₂ to C ₂₀ , or a mixture thereof.
The method according to claim 1,
Wherein the polyolefin-based elastomer resin is a resin selected from the group consisting of resins having a shore A hardness of 40 to 90 or a mixture thereof.
The method according to claim 1,
Wherein the base resin composition further comprises at least one additive selected from the group of additives consisting of an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant, a metal deactivator, a pigment, a dye, a nucleating agent, a crosslinking agent and a cell modifier.
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