KR20220068797A - Polypropylene resin composition having improved elongation viscosity - Google Patents

Abstract

Disclosed is a polypropylene resin composition which can improve blow moldability while maintaining transparency and impact resistance of polypropylene in order to be applied to blow molding containers such as detergent containers, shampoo containers, etc. The present invention relates to a polypropylene resin composition for a blow molding container, comprising: 75-97 wt% of polypropylene; 1-10 wt% of linear low density polyethylene; 1-10 wt% of a copolymer of ethylene and α-olefin having 2-10 carbon atoms as thermoplastic elastomer rubber; and 0.01-5 wt% of a resin mixture having a core-shell structure in which the core is a fluorine-based resin and the shell is a styrene-acrylonitrile (SAN) resin.

Description

Polypropylene resin composition having improved elongation viscosity}

The present invention relates to a polypropylene resin composition for blow-molded containers, and more particularly, to a polypropylene resin composition for high-transparency and high-impact blow-molded containers.

Materials for use in household containers such as food containers, detergent containers, shampoo containers, etc. require transparency and impact resistance. Due to these required characteristics, polyethylene terephthalate and polypropylene are mainly used. Due to the regulations of the Ministry of Environment such as Jiyang and uni-materialization, the development of polypropylene materials is active. In addition, the transparency of household containers is further emphasized for product reliability and the like.

Such a container is manufactured by blow molding, and in order to facilitate blow moldability of polypropylene, the stretch viscosity of the resin must be higher than a certain level. Conventional high-transparency and high-impact polypropylene is mixed with linear low-density polyethylene (mLLDPE) prepared with a metallocene catalyst to facilitate blow moldability, but this alone does not have sufficient elongation viscosity, so it is difficult to sufficiently improve blow moldability.

Japanese Patent Registration No. 2942888 suggests a technique for improving melt strength by adding polytetrafluoroethylene and alkyl (meth) acrylate having 5 to 30 carbon atoms to a polyolefin-based resin, but the possibility of lowering transparency due to the added material There is this.

Korean Patent No. 1499360 uses polytetrafluoroethylene and an alkyl (meth)acrylate-based polymer having 5 to 30 carbon atoms to prepare a polypropylene resin composition having high melt tension, but also reduces the transparency of polypropylene there is a possibility to do

Korean Patent Registration No. 1349588 relates to a polypropylene-based resin composition having excellent melt strength and a method for manufacturing the same. Although a fluororesin is used to increase the melt strength, but by mixing it with an inorganic filler, the effect on the transparency of the fluororesin is considered Did not do it.

An object of the present invention is to provide a polypropylene resin composition capable of improving blow moldability while maintaining transparency and impact resistance of polypropylene for application to blow molding containers such as detergent containers and shampoo containers.

The present invention in order to solve the above problems, polypropylene 75 to 97% by weight; 1 to 10% by weight of linear low density polyethylene; 1 to 10% by weight of a copolymer of ethylene and an α-olefin having 2 to 10 carbon atoms as a thermoplastic elastomer rubber; And the core is a fluorine-based resin, the shell is a styrene-acrylonitrile (Styrene-acrylonitrile; SAN) resin core-shell structure resin mixture 0.01 to 5% by weight; provides a polypropylene resin composition for a blow molding container comprising a; .

In addition, the polypropylene is an ethylene-propylene random copolymer having a melt index (230° C., 2.16 kg load) of 0.1 to 5 g/10 min and an ethylene content of 1 to 10 wt %, and the linear low density polyethylene has a melt index (190 ℃, 2.16 kg load) is 0.1 to 5 g / 10 min, the density is 0.900 to 0.940 g / ㎤, is a linear low density polyethylene prepared with a metallocene catalyst, the thermoplastic elastomer rubber has a melt index (190 ℃, 2.16 kg load) is 0.1 to 5 g/10 min, the density is 0.860 to 0.910 g/cm 3 , and ethylene-butene rubber (EBR) containing 60 to 80% by weight of ethylene and 20 to 40% by weight of butene, and , The resin mixture of the core-shell structure is polytetrafluoroethylene (PTFE) having an average diameter of 0.05 to 0.5 μm as a core, and each of the core and the shell is included in an amount of 40 to 60% by weight. A polypropylene resin composition is provided.

In addition, the resin composition has an elongation viscosity of 100,000 to 200,000 Pa·s measured according to the following method, a light transmittance of 77% or more, and an impact strength of 55 to 70 kgf·cm/cm for blow molding containers, characterized in that A polypropylene resin composition is provided.

[How to measure]

ARES EVF (Extensional Viscosity Fixture) was used to measure the maximum elongational viscosity of the specimen at 160°C temperature and 0.1/sec speed conditions, and according to ASTM D1003, the light transmittance (Total Transmittance) was measured for the specimen (3 mm thickness) using a hazemeter. ) and measure the u-notched Izod impact strength of the specimen (3 mm thick) at room temperature according to ASTM D256.

According to the present invention, polypropylene with improved blow moldability by adding a resin mixture having a core-shell structure in which a core is a fluorine-based resin and a shell is a styrene-acrylonitrile resin to a high-transparency and high-impact polypropylene resin to improve elongation viscosity A resin composition can be provided.

In addition, it is possible to provide a polypropylene resin composition capable of maintaining high transparency and high impact properties by minimizing the content of the resin mixture having a core-shell structure.

Hereinafter, the present invention will be described in detail through preferred embodiments. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Accordingly, since the configuration of the embodiments described in the present specification is only the most preferred embodiment of the present invention and does not represent all the technical spirit of the present invention, various equivalents and modifications that can be substituted for them at the time of the present application It should be understood that there may be

The present inventors face the fact that there is no conventional resin composition having improved blow moldability while maintaining high transparency and high impact properties in the polypropylene resin composition for blow molding containers, and as a result of repeated research, high transparency and high impact polypropylene It has been found that by minimizing the amount of the resin mixture having a specific core-shell structure added to the resin, it is possible to improve the blow moldability by improving the elongation viscosity while maintaining high transparency and high impact properties, and thus the present invention has been reached.

Accordingly, the present invention comprises 75 to 97% by weight of polypropylene; 1 to 10% by weight of linear low density polyethylene; 1 to 10% by weight of a copolymer of ethylene and an α-olefin having 2 to 10 carbon atoms as a thermoplastic elastomer rubber; and 0.01 to 5% by weight of a resin mixture having a core-shell structure in which the core is a fluorine-based resin and the shell is a styrene-acrylonitrile resin.

In the present invention, the polypropylene may be a propylene homopolymer or a random copolymer copolymerized with propylene and α-olefin having 2 to 10 carbon atoms in an amount of 10 wt% or less as a base resin for imparting transparency and impact resistance.

The polypropylene may preferably be a random copolymer in terms of improving the stretching viscosity, more preferably an ethylene-propylene random copolymer having an ethylene content of 1 to 10% by weight, and even more preferably ethylene Ethylene-propylene random copolymers having a content of 2 to 5% by weight can be used.

The polypropylene preferably has a melt index (230° C., 2.16 kg load) of 0.1 to 5 g/10min, more preferably 0.5 to 2 g/10min. If the melt index is less than 0.1 g/10 min, surface defects such as gel generation or fish-eye may occur, and if it exceeds 5 g/10 min, a long branched structure is relatively weakly generated during the reaction, resulting in lowered elongation viscosity. have.

The polypropylene may be included in an amount of 75 to 97% by weight in the total resin composition, preferably 80 to 90% by weight, and more preferably 84 to 88% by weight. When the polypropylene content is less than 75% by weight, transparency and impact resistance of the final resin composition are reduced, and when it exceeds 97% by weight, the elongation viscosity of the final resin composition is reduced.

In the present invention, the linear low-density polyethylene is mixed with the polypropylene to improve blow moldability, and linear low-density polyethylene (mLLDPE) prepared with a metallocene catalyst may be preferably used.

The linear low-density polyethylene is polymerized at a lower pressure and temperature than low-density polyethylene, and in general, a copolymer obtained by adding a small amount of an α-olefin comonomer having 2 to 10 carbon atoms to ethylene may be used, wherein the α-olefin is 1 It is preferable that it is -hexene or 1-octene, and it is more preferable that it is 1-hexene.

The linear low-density polyethylene may have a density of 0.900 to 0.940 g/cm 3 , preferably 0.910 to 0.930 g/cm 3 , and improve elongation viscosity while maintaining transparency and impact resistance when mixed with the polypropylene The melt index (230° C., 2.16 kg load) is preferably 0.1 to 5 g/10 min, and more preferably 1 to 3 g/10 min.

The linear low-density polyethylene may be included in an amount of 1 to 10% by weight, preferably 2 to 8% by weight, and more preferably 3 to 7% by weight in the total resin composition. When the content of the linear low-density polyethylene is less than 1% by weight, the effect of improving the elongation viscosity of the final resin composition is insufficient, and when it exceeds 10% by weight, the transparency and impact resistance of the final resin composition are deteriorated.

In the present invention, a copolymer of ethylene and α-olefin having 2 to 10 carbon atoms is included as a thermoplastic elastomer rubber in order to prevent a decrease in the impact resistance of the final resin composition.

The thermoplastic elastomer rubber contains 60 to 80% by weight of ethylene and 20 to 40% by weight of butene in terms of maintaining high transparency and improved blow moldability in combination with the polypropylene, linear low-density polyethylene, and a resin mixture having a core-shell structure to be described later. Ethylene-butene rubber (EBR) containing weight % may be preferably used, wherein the density may be 0.860 to 0.910 g/cm 3 , preferably 0.870 to 0.900 g/cm 3 , and the melt index ( 190°C, 2.16 kg load) may be 0.1 to 5 g/10 min, preferably 1 to 3 g/10 min.

The thermoplastic elastomer rubber may be included in an amount of 1 to 10% by weight, preferably 3 to 10% by weight, and more preferably 5 to 10% by weight in the total resin composition. When the content of the thermoplastic elastomer rubber is less than 1% by weight, the effect of preventing deterioration of the impact resistance of the final resin composition is insufficient, and when it exceeds 10% by weight, the transparency and blow moldability of the final resin composition are deteriorated.

In the present invention, in the resin mixture having a core-shell structure, the core is a fluorine-based resin and the shell is a styrene-acrylonitrile resin. improve the stretching viscosity.

As a mixture composition suitable for imparting these properties, in the present invention, the core is polytetrafluoroethylene (PTFE) with an average diameter of 0.05 to 0.5 μm, and the shell is a styrene-acrylonitrile (SAN) resin, each of 40 to A resin mixture having a core-shell structure containing 60% by weight may be applied.

The resin mixture having the core-shell structure may be included in an amount of 0.01 to 5% by weight, preferably 0.01 to 3% by weight, and more preferably 0.01 to 1% by weight in the total resin composition. When the content of the resin mixture of the core-shell structure is less than 0.01 wt %, the desired effect is insufficient, and when the content is excessive, the transparency and impact resistance of the final resin composition are deteriorated.

In addition to the above components, the polypropylene resin composition according to the present invention may further include a neutralizing agent, antioxidant, nucleating agent, antistatic agent, etc. which are generally used when applied for blow molding containers.

The polypropylene resin composition for blow molding containers according to the present invention may be prepared by mixing and extruding the above components according to a conventional method known in the art. For example, the components may be introduced into a twin-screw extruder and melt-kneaded to prepare a polypropylene resin composition.

The polypropylene resin composition for blow molding containers according to the present invention has improved blow moldability while maintaining high transparency and high impact properties, and specifically has an elongation viscosity of 100,000 to 200,000 Pa·s, preferably measured according to the following method. 100,000 to 150,000 Pa·s, the light transmittance is 77% or more, preferably 79% or more, and the impact strength may be 55 to 70 kgf·cm/cm, preferably 60 to 65 kgf·cm/cm.

[How to measure]

ARES EVF (Extensional Viscosity Fixture) was used to measure the maximum elongational viscosity of the specimen at 160°C temperature and 0.1/sec speed conditions, and according to ASTM D1003, the light transmittance (Total Transmittance) was measured for the specimen (3 mm thickness) using a hazemeter. ) and measure the u-notched Izod impact strength of the specimen (3 mm thick) at room temperature according to ASTM D256.

Hereinafter, the present invention will be described in more detail through specific examples and comparative examples. In Examples and Comparative Examples, density, melt index and molecular weight properties were measured according to the following method.

[How to measure]

(1) Density

It was measured according to ASTM D1505.

(2) Melt flow index (MI)

According to ASTM D1238, it was measured under a load of 2.16 kg, (A) at 230°C for polypropylene, and (B) at 190°C for linear low-density polyethylene.

Example 1

(A) polypropylene (MI 0.9 g/10 min, ethylene-propylene random copolymer with an ethylene content of 3.5 wt %) 86.5 wt %, (B) a linear low-density polyethylene prepared with a metallocene catalyst (MI 2 g/10 min, density) 0.918 g/cm 3, comonomer 1-hexene, SP310, LG Chem) 5% by weight, (C) 2 g of ethylene-butene rubber (EBR) containing 70% by weight of ethylene and 30% by weight of butene (MI (190°C)) /10 min, density 0.885 g/cm 3 , Tafmer DF810, Mitsui chemical) 8 wt %, (D) the core is polytetrafluoroethylene (PTFE) (average particle diameter 0.2 μm), and the shell is styrene-acrylonitrile (SAN) ) 0.01% by weight of a resin mixture with a core-shell structure (POLY TS AD001, PACIFIC) containing 50% by weight each as a resin and (E) a phenolic antioxidant (AO-1010, Cas No. 6683-19-8) as an additive and phosphorus-based antioxidant (A-240, Cas No. 31570-04-4) 　 0.5% by weight in total was added to a twin-screw extruder having a screw length/diameter (L/D) ratio of 40 and melt-kneaded at 180 to 220° C. It solidified by cooling to prepare a resin composition in the form of pellets.

Examples 2-3 and Comparative Examples 1-2

A resin composition was prepared in the same manner as in Example 1, except that the component content in Example 1 was changed to the conditions shown in Table 1 below.

ingredient Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 A (wt%) 86.5 76.5 86.49 85.5 81.5 B (wt%) 5 5 5 5 5 C (wt%) 8 8 8 8 8 D (wt%) - 10 0.01 One 5 E (wt%) 0.5 0.5 0.5 0.5 0.5

Experimental example

Various test pieces were prepared from the prepared resin composition, and the elongation viscosity, light transmittance and impact strength were measured by the following method, and the results are shown in Table 2 below.

[How to measure]

(1) elongation viscosity

ARES EVF (Extensional Viscosity Fixture) was used to measure the maximum elongational viscosity of the specimen (1 mm thickness) at a temperature of 160° C. and a rate of 0.1/sec.

(2) light transmittance

According to ASTM D1003, light transmittance (Total Transmittance) was measured using a hazemeter for a specimen (2 mm thick).

(3) Impact strength

According to ASTM D256, the u-notched Izod impact strength of the specimen (3 mm thick) at room temperature was measured.

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Stretched viscosity (Pa·s) 78,045 177,210 110,675 116,980 142,120 Light transmittance (%) 79.7 76.4 79.8 79.9 80.5 Impact strength (kgf cm/cm) 62.5 49.5 62.5 61.9 60.8

Referring to Table 2, in the case of a polypropylene resin composition prepared by mixing a polypropylene, linear low-density polyethylene and a thermoplastic elastomer rubber of a specific composition with a core-shell structure resin mixture of a specific composition including PTFE according to the present invention ( Examples 1 to 3) It can be seen that the effect of improving the stretching viscosity without lowering the light transmittance and impact resistance.

On the other hand, when the resin mixture having the core-shell structure is not added (Comparative Example 1), there is no effect of improving the stretching viscosity, however, when the resin mixture having the core-shell structure is added in excess (Comparative Example 2), the stretching viscosity is further improved, but it can be seen that the light transmittance and impact strength are significantly lowered.

On the other hand, as the content of the resin mixture of the core-shell structure increases, the elongation viscosity is improved, but a sufficient elongation viscosity improvement effect is realized even at a very small content, and further, in consideration of further prevention of deterioration of transparency and impact resistance, the core-shell structure It can be seen that the content of the resin mixture is preferably used in a relatively small content.

The preferred embodiment of the present invention has been described in detail above. The description of the present invention is for illustrative purposes, and those of ordinary skill in the art to which the present invention pertains will understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Accordingly, the scope of the present invention is indicated by the claims described below rather than the above detailed description, and all changes or modifications derived from the meaning, scope, and equivalent concept of the claims are included in the scope of the present invention. should be interpreted

Claims (3)

75 to 97% by weight of polypropylene;
1 to 10% by weight of linear low density polyethylene;
1 to 10% by weight of a copolymer of ethylene and α-olefin having 2 to 10 carbon atoms as a thermoplastic elastomer rubber; and
0.01 to 5 wt% of a resin mixture having a core-shell structure in which the core is a fluorine-based resin and the shell is a Styrene-acrylonitrile (SAN) resin;
A polypropylene resin composition for blow molding containers comprising a. The method of claim 1,
The polypropylene is an ethylene-propylene random copolymer having a melt index (230° C., 2.16 kg load) of 0.1 to 5 g/10 min, and an ethylene content of 1 to 10% by weight,
The linear low-density polyethylene has a melt index (190° C., 2.16 kg load) of 0.1 to 5 g/10min, a density of 0.900 to 0.940 g/cm 3 , and a linear low-density polyethylene prepared with a metallocene catalyst,
The thermoplastic elastomer rubber has a melt index (190°C, 2.16 kg load) of 0.1 to 5 g/10min, a density of 0.860 to 0.910 g/cm 3 , and 60 to 80% by weight of ethylene and 20 to 40% by weight of butene. Ethylene-butene rubber (EBR),
The resin mixture of the core-shell structure is polytetrafluoroethylene (PTFE) having an average diameter of 0.05 to 0.5 μm in the core, and the core and the shell are polytetrafluoroethylene (PTFE), each comprising 40 to 60% by weight. Propylene resin composition. The method of claim 1,
The resin composition has a stretch viscosity of 100,000 to 200,000 Pa·s measured according to the following method, a light transmittance of 77% or more, and an impact strength of 55 to 70 kgf·cm/cm. Poly for blow molding containers Propylene resin composition:
[How to measure]
ARES EVF (Extensional Viscosity Fixture) was used to measure the maximum elongational viscosity of the specimen at a temperature of 160°C and a rate of 0.1/sec. ) and measure the u-notched Izod impact strength of the specimen (3 mm thick) at room temperature according to ASTM D256.