KR20160061073A - Method for manufacturing olefin resin moldings and olefin resin moldings - Google Patents

Abstract

The present invention relates to a method for manufacturing an olefin resin molded product and an olefin resin molded product. The a method for manufacturing an olefin resin molded product comprises the step of: producing a molded product having isotropic crystals by cooling an olefin resin composition at 0 to 30°C after forming the olefin resin composition including two or more metal salt compounds and an olefin block copolymer; and thermal-forming the molded product at 150 to 200°C.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing an olefin resin molded article,

The present invention relates to a method for producing an olefin resin molded article and an olefin resin molded article. More particularly, the present invention relates to a method for producing an olefin resin molded article having improved heat stability and mechanical properties in a thermoforming step, and an olefin resin molded article using the same.

The olefin block copolymer is a general-purpose olefin resin used in a special situation and is used in a wide variety of applications such as food containers, short sheets, various household goods, and industrial materials. The reason why the olefin block copolymer is used in various ways is that it is less toxic than other plastics and has better physical properties such as low temperature impact strength than homo-polypropylene and good processability. In particular, since it is not decomposed by an acidic or basic solution (concrete) and has excellent chemical resistance, it is widely used for building materials and food containers for various purposes. Among them, it is also used as a material for the heat container.

 At present, the honeycomb container is manufactured by thermoforming an olefin block copolymer, but there are limitations such as a deformation problem of the product due to the shrinkage difference depending on the anisotropic crystal of the polypropylene, .

Accordingly, there is a demand for development of a method for manufacturing a molded article which can minimize the deformation of the product due to thermoforming.

The present invention provides a method for producing an olefin resin molded article for producing an olefin resin molded article improved in heat stability and mechanical properties in a thermoforming process.

The present invention also provides an olefin resin molded article using the olefin resin molded article production method.

In the present specification, an olefin resin composition containing two or more metal salt mixtures and an olefin block copolymer is molded and cooled to a temperature of 0 ° C to 30 ° C to produce a molded article having isotropic crystals formed thereon; And thermoforming the molded article at a temperature of 150 ° C to 200 ° C.

The present invention also provides an olefin resin molded article comprising an isotropic crystal containing two or more metal salt mixtures and an olefin block copolymer.

Hereinafter, a method for producing an olefin resin molded article and an olefin resin molded article according to a specific embodiment of the present invention will be described in detail.

As used herein, '(alone) polymer' means a polymer polymerized with only one monomer of ethylene or propylene or -olefin.

In the present specification, an '(olefin) block copolymer' is a polymer in which ethylene or propylene is copolymerized with an -olefin, and has physical or chemical properties, for example, ethylene or propylene, Refers to a copolymer comprising a plurality of repeating unit blocks or segments that are different from each other in the polymer so that at least one of the characteristics such as the content (molar fraction), crystallinity, density, or melting point of the repeating units is different from each other do.

According to one embodiment of the present invention, an olefin resin composition comprising at least two metal salt mixtures and an olefin block copolymer is formed and cooled to a temperature of 0 ° C to 30 ° C to produce a molded article having isotropic crystals formed thereon; And thermoforming the molded article at a temperature of 150 ° C to 200 ° C.

The present inventors have found that when the above-mentioned specific olefin resin molded article manufacturing method is used, isotropic crystals are produced in a molded product by a mixture of two or more metal salts, and therefore, when thermoforming is carried out at a specific temperature condition, And that the mechanical properties of the molded article can be improved by experiments, and the invention is completed.

Specifically, the method for producing an olefin resin molded article includes a step of molding an olefin resin composition containing two or more metal salt mixtures and an olefin block copolymer, and cooling the mixture to a temperature of 0 ° C to 30 ° C to produce a molded article having isotropic crystals .

Examples of the method for molding the olefin resin composition are not limited. For example, various molding methods such as injection molding, extrusion molding, extrusion blow molding, injection blow molding and profile extrusion molding can be used without limitation, An extrusion molding method can be used.

The shape of the olefin resin composition is not particularly limited, but may be preferably in the form of pellets.

The specific shape and size of the molded article may be determined depending on the application purpose, and is not particularly limited, but may be, for example, in the form of a sheet.

 Isotropic crystals may be formed in the molded product. The term 'isotropic' refers to a characteristic in which crystals are generated in the X-Y axis direction and have the same physical properties in all directions. Accordingly, when thermoforming the molded product at a specific temperature condition, it is possible not only to minimize the deformation of the final molded product, but also to improve the mechanical properties of the molded product.

As described above, the olefin resin composition containing the above-mentioned two or more metal salt mixtures and the olefin block copolymer is molded and cooled to a temperature of 0 ° C to 30 ° C, 3 ° C to 27 ° C, or 22 ° C to 27 ° C Isotropic crystals may be formed in the molding.

If the temperature for cooling is excessively low, there is not enough time for the isotropic crystal to be formed in the molded product, so that the isotropic crystallinity may be lowered, thereby causing apparent deformation of the olefin resin molded article.

A specific example of the cooling method is not limited to a specific one. For example, a cooling method using a coolant in a cooling roll may be used.

In addition, the olefin resin composition may include a mixture of two or more metal salts. The mixture of two or more metal salts acts as a nucleating agent to improve the rigidity of the molded article produced by the olefin resin molded article manufacturing method and to shorten the production time effectively by increasing the isotropic crystallization rate.

The olefin resin composition may further comprise various known compounds capable of acting as a nucleating agent such as a phosphate ester compound, a spontaneous compound, sodium benzoate, talc, titanium oxide and the like in addition to a mixture of two or more metal salts.

The mixture of two or more metal salts contained in the olefin resin composition may include a mixture of salts of two or more metals selected from the group consisting of lithium, sodium, magnesium, calcium, barium, aluminum and zinc, Mixtures of calcium salts may be used.

More specifically, the two or more metal salt mixtures may comprise a zinc salt and a calcium salt, wherein the weight ratio of the zinc salt and the calcium salt is from 1: 1 to 1:10, or from 1: 1.5 to 1: 5, or 1: 1.8 to 1: 3.

Examples of the metal salt include, but are not limited to, chlorides, nitrates, nitrates, nitrates, carbonates, carboxylates, oxides and hydroxides of the metals.

The mixture of two or more metal salts may have a plate-like structure. The plate-like structure means a structure arranged like a thin plate, and as the mixture of two or more kinds of metal salts has a plate-like structure, isotropic crystals can be formed in the molded article.

The content of the two or more metal salt mixtures may be 0.01 to 0.5 parts by weight, or 0.03 to 0.4 parts by weight, or 0.04 to 0.3 parts by weight based on 100 parts by weight of the olefin block copolymer.

When the content of the mixture of two or more metal salts is less than 0.01 part by weight with respect to 100 parts by weight of the olefin block copolymer, a significant change in physical properties such as flexural modulus and low temperature impact strength of the molded article produced by the olefin resin molded article production method It may not occur. If the content of the two or more metal salt mixtures exceeds 0.5 parts by weight based on 100 parts by weight of the olefin block copolymer, no further improvement in physical properties is exhibited.

In addition, the olefin resin composition may include an olefin block copolymer. The olefin block copolymer may include an ethylene-based repeating unit and an? -Olefin-based repeating unit having 3 to 30 carbon atoms. The block copolymer refers to a copolymer having a plurality of repeating unit blocks or segments and may include a soft elastic block referred to as a soft segment and a hard crystalline block referred to as a hard segment.

The ethylene-based repeating unit refers to a repeating unit contained in an ethylene homopolymer produced from an ethylene compound as a monomer, and the? -Olefin-based repeating unit having 3 to 30 carbon atoms includes propene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, Means a repeating unit contained in a homopolymer prepared from an olefin compound as a monomer.

The content of the ethylene-based repeating unit may be 4 to 12 parts by weight, 4.5 to 8 parts by weight, or 4.8 to 6 parts by weight based on 100 parts by weight of the olefin block copolymer. If the content of the ethylene-based repeating unit is less than 4 parts by weight based on 100 parts by weight of the olefin block copolymer, the low temperature impact strength of the molded article produced by the olefin resin molded article production method may be lowered, Is more than 12 parts by weight based on 100 parts by weight of the olefin block copolymer, the rigidity of the molded article produced by the olefin resin molded article production method may be lowered and the production may be difficult in the process.

The melt index (measured at 230 占 폚 under a load of 2.16 kg in accordance with ASTM D1238) of the olefin block copolymer is from 0.4 g / 10 min to 2.0 g / 10 min, or from 0.4 g / 10 min to 0.8 g / 10 min, or from 0.45 g / 0.6 g / 10 min.

The melt index (MI) is a flow rate when a melt is extruded from a piston under a certain condition, and means an index indicating easiness of flow of the melt. The factors that have the greatest influence on the melt index are molecular weight and molecular weight distribution. Examples of the method of measuring the melt index are not limited, but can be measured using, for example, the ASTM D1238 method (temperature at 230 캜, measured at a load of 2.16 g).

If the melt index of the olefin block copolymer is less than 0.4 g / 10 min, production of the olefin block copolymer may be difficult due to process problems. If the melt index of the olefin block copolymer exceeds 2.0 g / 10 min, In the extrusion process of the block copolymer, the discharge amount is increased but the extrusion process condition needs to be changed.

Examples of the production method of the olefin block copolymer are not limited and can be produced by a conventional production method. For example, propylene and ethylene are simultaneously charged into a polymerization reactor, triethylaluminum, a phthalate catalyst, and a silane-based electron donor are introduced, and gas phase polymerization is carried out at a reaction temperature of 65 ° C to 75 ° C and a pressure of 32 atm to 34 atm. The ethylene-propylene block copolymer can be prepared by adjusting the melt index.

The olefin resin composition may further include an additive including an antioxidant, a neutralizer, an antistatic agent, an anti-blocking agent, a slip agent, a weathering stabilizer, a light stabilizer, a pigment, an inorganic filler or a mixture of two or more thereof. The content of the additive is not particularly limited, and may be, for example, 0.05 to 0.2 part by weight based on 100 parts by weight of the olefin block copolymer.

Examples of the antioxidant include, but are not limited to, phosphorus antioxidants and phenol antioxidants. Examples of the phosphorus antioxidants include tris (2,3-di-t-butylphenyl) phosphite And examples of the phenolic antioxidant include tetrakis [ethylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane.

Examples of the neutralizing agent are not particularly limited, but calcium stearate and the like can be used, for example.

Further, the olefin resin molded article manufacturing method may include thermoforming the molded article at a temperature of from 150 캜 to 200 캜, or from 155 캜 to 190 캜, or from 158 캜 to 165 캜. The molded article can be molded again into a molded article having a desired shape through thermoforming the molded article at a temperature of 150 to 200 ° C. As the molded article is heated at a temperature within the above specified range, the isotropic crystal It can be maintained without changing to amorphous. Thus, not only the deformation of the finally produced molded article can be minimized, but also the mechanical properties of the molded article can be improved.

If the temperature for thermoforming becomes too high, the isotropic crystals present in the molded article may become amorphous, and thus the appearance of the olefin resin molded article may be deformed.

For example, a method of softening the molded product by heating at a temperature of 150 ° C to 200 ° C and molding the molded product by injecting the soft product into a molding machine or a molding die, Can be used.

The 'softening' refers to a phenomenon when an amorphous material which does not exhibit a definite melting point such as asphalt, synthetic resin, rubber, glass or the like is heated to a certain temperature and softened.

According to another embodiment of the present invention, an olefin resin molded article comprising an isotropic crystal containing two or more metal salt mixtures and an olefin block copolymer may be provided.

Specifically, an olefin resin molded article produced by the olefin resin molded article manufacturing method of one embodiment can be provided.

The content of the at least two kinds of metal salt mixture, the olefin block copolymer and the isotropic crystal includes the above-mentioned contents in relation to the above embodiment.

Particularly, when the method for producing an olefin resin molded article is used, the difference in shrinkage percentage according to the following formula (1) of the olefin resin molded article may be 0.45% or less, or 0.01% to 0.20%.

[Equation 1]

Shrinkage percentage difference (%) = shrinkage percentage in mechanical direction (MD) - shrinkage percentage (%) in width direction (TD).

As described above, since the isotropic crystal produced by the mixture of two or more kinds of metal salts, the shrinkage rate difference according to the direction of Equation (1) decreases, and the deformation of the appearance of the product can be minimized.

If the difference in shrinkage percentage in the above-mentioned formula (1) of the olefin resin molded product is more than 0.45%, the difference between the shrinkage percentage in the mechanical direction (MD) and the shrinkage percentage in the transverse direction (TD) becomes too large, The molded article of the resin may be deformed by bending or the like and the shape stability due to heat may be reduced.

The molded article of the olefin resin has a flexural modulus measured at 23 DEG C and 50% relative humidity according to ASTM D790 of 14,000 kgf / cm2 or more, or 14,500 kgf / cm2 to 15,500 kgf / cm2, or 14,550 kg · f / cm 2 to 15,200 kg · f / cm 2.

The olefin resin molded article preferably has an IZOD impact strength of 4.6 kg · cm / cm or more, or 4.6 kg · cm / cm to 6.0 kg · cm / cm measured at -10 ° C. and 50% relative humidity according to ASTM D256, Or 4.7 kg · cm / cm to 5.0 kg · cm / cm. Accordingly, the olefin resin molded article can prevent cracking due to excellent impact strength at low temperatures.

The olefin resin molded article may be used as a food container, a packaging container, or a storage container, and the specific shape, size, color, etc. may be applied without limitation according to the use.

INDUSTRIAL APPLICABILITY According to the present invention, there can be provided an olefin resin molded article production method for producing an olefin resin molded article improved in heat stability and mechanical properties in a thermoforming step, and an olefin resin molded article using the same.

Fig. 1 shows an X-ray diffraction pattern of the molded article of an olefin resin produced in Example 2 and Comparative Example 3. Fig.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

< Manufacturing example  1 to 3 and Comparative Manufacturing Example  1 to 4: Preparation of polypropylene resin composition &gt;

(1) Preparation of ethylene-propylene block copolymer

The polymerization reactor was charged with propylene and ethylene at the same time, and triethylaluminum, a phthalate catalyst, and a silane-based electron donor were introduced, and gas-phase polymerization was carried out at a reaction temperature of 70 ° C and 33 atmospheric pressure to obtain ethylene- And the melt index was adjusted by hydrogen to 0.5 g / 10 min (230 ° C, 2.16 kg load).

(2) Production of polypropylene resin composition

The ethylene-propylene block copolymer, the nucleating agent, the phosphorus-based antioxidant, the phenol-based antioxidant and the neutralizing agent were mixed in the amounts shown in Table 1 for 5 minutes in a Henschel mixer and then extruded by a biaxial extruder at 200 ° C to prepare a pellet- A composition was prepared.

Production Example and Composition of Comparative Production Example Composition (unit: parts by weight) division A B1 B2 B3 C D E Production Example 1 100 0.05 - - 0.15 0.1 0.1 Production Example 2 100 0.1 - - 0.15 0.1 0.1 Production Example 3 100 0.2 - - 0.15 0.1 0.1 Comparative Preparation Example 1 100 - - - 0.15 0.1 0.1 Comparative Production Example 2 100 - 0.05 - 0.15 0.1 0.1 Comparative Production Example 3 100 - 0.1 - 0.15 0.1 0.1 Comparative Production Example 4 100 - - 0.1 0.15 0.1 0.1

* A: Ethylene-propylene block copolymer (manufactured by Lotte Chemical)

B1: a mixture of 34% of a zinc compound (N982) and 66% of a calcium salt (1,2-cyclohexanedicarboxylic acid calcium salt), a nucleating agent (manufactured by Milliken Co., Ltd.)

B2: sodium 2,2'-methylre Nevis- (4,6-di-tetra-butylphenyl) phosphorate, nucleating agent (manufacturer: ADEKA)

* B3: talc, nucleating agent (manufacturer: KOCH)

* C: Tris (2,3-di-t-butylphenyl) phosphite, phosphorus antioxidant (Manufacturer: Songwon Industry)

* D: tetrakis [ethylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, phenolic antioxidant

* E: Calcium stearate, neutralizing agent (Manufacturer: Songwon Industry)

< Example  1 to 3: Production of molded polypropylene resin articles>

(1) Production of polypropylene resin sheet

The polypropylene resin compositions of Production Examples 1 to 3 were put into a molding machine and molded into a sheet form, and a polypropylene resin sheet was produced through a cooling roll at a temperature of 25 캜.

(2) Production of polypropylene resin containers

The polypropylene resin sheet was heated at a temperature of 170 占 폚 for 3 minutes and then molded into a container shape using a thermoforming machine to produce a polypropylene resin container.

< Comparative Example  1 to 4: Production of molded polypropylene resin articles>

A polypropylene resin molded article was produced in the same manner as in the Examples except that the polypropylene resin compositions of Comparative Production Examples 1 to 4 were used in place of the polypropylene resin compositions of Production Examples 1 to 3.

< Experimental Example : Example  And In the comparative example  Measurement of physical properties of the obtained polypropylene resin molded article>

Properties of the polypropylene resin molded articles obtained in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Tables 3 and 4.

1. Flexural modulus (kg · f / cm 2)

The flexural modulus of the polypropylene resin containers obtained in Examples 1 to 3 and Comparative Examples 1 to 4 was measured according to ASTM D790 at 23 DEG C and 50% relative humidity.

2. Izod impact strength (kg · cm / cm)

The Izod impact strengths of the polypropylene resin containers obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were measured according to ASTM D256 at a temperature of -10 DEG C and a relative humidity of 50%.

3. Dupont impact strength (kg · cm)

The polypropylene resin containers obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were allowed to stand at -10 DEG C for about 4 hours, and then the impact strength of the dies was measured.

4. Heat deformation temperature (℃)

The polypropylene resin containers obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to ASTM D648 to measure the heat distortion temperature at a load of 4.6 kg · f.

5. Shrinkage difference (%)

The shrinkage percentage in the MD direction and the shrinkage percentage in the TD direction were measured with a microscope on the polypropylene resin sheets and containers obtained in Examples 1 to 3 and Comparative Examples 1 to 4, and the difference (MD shrinkage - TD shrinkage) was calculated

EXAMPLES AND COMPARATIVE EXAMPLES Experimental Example Results of Polypropylene Resin Molded Products division Flexural modulus (kg · f / ㎠) IZOD impact strength
[-10 ° C]
(kg · cm / cm) Dupont
[-10 ° C]
(kg · cm) Heat distortion temperature
(° C) Shrinkage difference (%)
[Sheet] Shrinkage difference (%)
[Vessel] Example 1 14,600 5.1 110 121.3 0.08 0.15 Example 2 15,100 5.0 115 125.1 0.03 0.10 Example 3 15,000 4.8 110 125.1 0.01 0.11 Comparative Example 1 13,200 5.2 110 114.7 0.20 0.40 Comparative Example 2 14,400 4.8 100 110.6 0.25 0.50 Comparative Example 3 15,200 4.5 95 128.2 0.39 0.71 Comparative Example 4 14,000 4.7 100 119.5 0.25 0.32

As shown in Table 2, in Examples 1 to 3 in which zinc and calcium salt compounds as nucleating agents were added to the ethylene-propylene block copolymer, the flexural modulus and thermal deformation It was confirmed that not only the mechanical properties were improved but also the difference in shrinkage percentage of the sheet or the container was relatively small and the thermal stability was excellent.

On the other hand, in Comparative Examples 2 to 3 in which nucleating agent sodium 2,2'-methylre Nevis- (4,6-di-tetra-butylphenyl) phosphite was added to an ethylene-propylene block copolymer and Comparative Examples 4, mechanical properties such as flexural modulus and the like were measured at the same level as those of Examples 1 to 3, but it was confirmed that the difference in shrinkage percentage of the sheet or the container was relatively large and the thermal stability was reduced.

6. X-ray diffraction pattern (XRD)

(1) X-ray diffraction patterns (XRD) were measured using the polypropylene resin molded articles obtained in Example 2 and Comparative Example 3, and the results are shown in FIG.

(2) In Example 2 and Comparative Example 3, peaks were observed at 14 degrees, 17 degrees, 18.5 degrees, 21 degrees and 22 degrees, and (1 1 0), (0 4 0), (1 3 0) , I-PP monoclinic alpha crystals of (1 1 1) and (1 3 1) + (0 4 1). Also, it can be seen that the peaks at 16 degrees and 21 degrees are beta crystals of i-PP triangles of (3 0 0) and (3 0 1).

On the other hand, in Example 2, the peak intensity of the (0 4 0) plane of 17 degrees is much higher than that of Comparative Example 3. Specifically, it can be confirmed that the intensity of Example 2 is twice as high as that of Comparative Example 3 at a 17 degree peak.

The zinc and calcium salt nucleating agent used in Example 2 had a plate-like structure. The sodium 2,2'-methylre Nevis- (4,6-di-tetra-butylphenyl) phosphite nucleating agent used in Comparative Example 3 was in the form of needle, It can be confirmed that an isotropic crystal is produced due to the zinc and calcium salt nucleating agent in the plate-like structure through the tendency of the crystal orientation of Example 2 to increase.

The crystal of the isotropic crystal is randomly oriented in the X-axis and the Y-axis, minimizing the shrinkage difference in the MD / TD direction, and it is possible to improve the distortion caused in the plasticizing process.

< Example  4 to 8: Production of molded polypropylene resin articles>

(1) Production of polypropylene resin sheet

The polypropylene resin composition of Production Example 2 was put into a molding machine and molded into a sheet form, and a polypropylene resin sheet was produced through a cooling roll having the cooling temperature shown in Table 3 below.

(2) Production of polypropylene resin containers

The polypropylene resin sheet was heated at a heating temperature shown in Table 3 below for 3 minutes and then molded into a container shape using a thermoforming machine to produce a polypropylene resin container.

< Comparative Example  5 to 9: Production of molded polypropylene resin articles>

A polypropylene resin molded article was produced in the same manner as in Example 1, except that the polypropylene resin composition of Comparative Production Example 3 was used in place of the polypropylene resin composition of Production Example 2. [

The shrinkage percentage in the MD direction and the shrinkage percentage in the TD direction were measured with a microscope on the polypropylene resin containers obtained in Examples 2, 4 to 8 and Comparative Examples 3 and 5 to 9, and the difference (MD shrinkage - TD shrinkage) Was calculated

EXAMPLES AND COMPARATIVE EXAMPLES Molding conditions and experimental results of polypropylene resin molded articles division Cooling temperature (℃) Heating temperature (℃) Shrinkage difference (%) Example 2 25 170 0.10 Example 4 25 160 0.05 Example 5 5 160 0.12 Example 6 5 170 0.17 Example 7 25 180 0.13 Example 8 5 180 0.14 Comparative Example 3 25 170 0.71 Comparative Example 5 25 160 0.70 Comparative Example 6 5 160 0.74 Comparative Example 7 5 170 0.79 Comparative Example 8 25 180 0.50 Comparative Example 9 5 180 0.79

As shown in Table 3, in the case of the example in which zinc and calcium salt compounds were added as nucleating agent to the ethylene-propylene block copolymer, sodium 2,2'-methylre Nevis- (4 , 6-di-tetra-butylphenyl) phosphite was added, the difference in shrinkage ratio of the polypropylene resin container was reduced.

As described above, in the above comparative example in which the difference in shrinkage ratio of the polypropylene resin container is large, the shape can be warped during the thermoforming process, while in the case of the above embodiment in which the difference in shrinkage percentage of the polypropylene resin container is small, You can see that it keeps its shape.

In addition, among the examples in which zinc and calcium salt compounds as nucleating agents were added to the ethylene-propylene block copolymer, the difference in the shrinkage rate was decreased as the cooling temperature was higher and the heating temperature was lower, .

1: X-ray diffraction pattern of Comparative Example 3
2: X-ray diffraction pattern of Example 2

Claims (15)

Molding an olefin resin composition containing at least two kinds of metal salt mixtures and an olefin block copolymer and cooling the mixture at a temperature of 0 占 폚 to 30 占 폚 to produce a molded article having isotropic crystals; And
And thermoforming the molded article at a temperature of 150 ° C to 200 ° C.
The method according to claim 1,
Wherein the two or more metal salts include a salt of two or more metals selected from the group consisting of lithium, sodium, magnesium, calcium, barium, aluminum and zinc.
The method according to claim 1,
Wherein the mixture of two or more metal salts comprises a zinc salt and a calcium salt.
The method of claim 3,
Wherein the weight ratio of the zinc salt and the calcium salt is from 1: 1 to 1:10.
The method according to claim 1,
Wherein the mixture of two or more metal salts has a plate-like structure.
The method according to claim 1,
Wherein the content of the two or more metal salt mixtures is 0.01 to 0.5 parts by weight based on 100 parts by weight of the olefin block copolymer.
The method according to claim 1,
Wherein the olefin block copolymer comprises an ethylene-based repeating unit and an? -Olefin-based repeating unit having 3 to 30 carbon atoms.
8. The method of claim 7,
Wherein the content of the ethylene-based repeating unit is 4 to 12 parts by weight based on 100 parts by weight of the olefin block copolymer.
The method according to claim 1,
Wherein the olefin block copolymer has a melt index of 0.4 g / 10 min to 2.0 g / 10 min as measured at 230 占 폚 under a load of 2.16 kg in accordance with ASTM D1238.
The method according to claim 1,
Wherein the olefin resin composition further comprises at least one additive selected from the group consisting of an antioxidant, a neutralizing agent, an antistatic agent, an anti-blocking agent, a slip agent, a weathering stabilizer, a light stabilizer, a pigment and an inorganic filler.
At least two metal salt mixtures and an olefin block copolymer,
Wherein an isotropic crystal is formed.
12. The method of claim 11,
Wherein the difference in shrinkage percentage according to the following formula (1) is 0.45% or less:
[Equation 1]
Shrinkage percentage difference (%) = shrinkage percentage in mechanical direction (MD) - shrinkage percentage (%) in width direction (TD).
12. The method of claim 11,
Wherein the flexural modulus measured by ASTM D790 at 23 DEG C and 50% relative humidity is 14,000 kgf / cm &lt; 2 &gt; or more.
12. The method of claim 11,
The IZOD impact strength measured by ASTM D256 at -10 ° C and 50% relative humidity is 4.6 kg · cm / cm or more.
12. The method of claim 11,
An olefin resin molded article used as a food container, packaging container or storage container.

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