KR20050067655A - Polypropylene composition for extrusion coating - Google Patents

Abstract

The present invention relates to a resin composition comprising a polypropylene for extrusion coating, a long branch is introduced, the melt strength is 200mN or more, the melt index of 10 ~ 30g / 10 minutes according to ASTM D1238 standard at 200 ℃, 2.16kg conditions will be. According to the present invention, it is possible to provide a polypropylene resin composition suitable for extrusion coating because the melt tension is superior to that of the existing resin, so that the high-speed processability, heat adhesiveness, neck toughness, and weaving characteristics are excellent.

Description

Polypropylene Resin Composition for Extrusion Coatings {POLYPROPYLENE COMPOSITION FOR EXTRUSION COATING}

The present invention relates to a polypropylene resin composition for extrusion coating, and more particularly, to a polypropylene resin composition for extrusion coating having excellent high-speed processing and neck-in properties, including a polypropylene resin having a long branch introduced therein. It is about.

In general, when the OPP film is used for food packaging, it is used by extrusion coating a polyolefin resin to improve the rigidity of the film. As the resin for extrusion coating, many branched low density polyethylenes having a density of 0.920 g / cm 3 or less are used. However, such low density polyethylene is difficult to apply when the strength is weak and requires high strength. In order to solve these disadvantages, a polypropylene resin having excellent rigidity may be used, but the polypropylene resin has a weak neck toughness.

 The present invention is to solve the problems as described above, to provide a polypropylene resin composition for extrusion coating excellent in heat resistance and melt tension, excellent in high-speed processing, heat adhesiveness, neck toughness and weaving (weaving) properties It is done.

The resin composition of the present invention has a long branch is introduced, the melt strength is 200mN or more, 100 parts by weight of polypropylene and the antioxidant 0.1 ~ 10 ~ 30g / 10 minutes according to ASTM D1238 standard at 200 ℃, 2.16kg conditions It is characterized by consisting of 1.0 parts by weight.

The polypropylene polymer having a long branch introduced in the present invention is polymerized by a conventional method using a prepolymerization catalyst in a form in which a high molecular weight monomer is encapsulated around the catalyst for alpha olefin polymerization, and a catalyst used for its preparation. The components are described in Korean Patent Application No. 2001-0085640, which the applicant has already filed. To summarize the catalyst components, the solid titanium catalyst for olefin polymerization is surface treated with a silane compound having two or more vinyl groups, and then the surface treatment is performed by prepolymerizing the surface treated solid titanium catalyst with an olefin monomer and a diene compound. A catalyst for alpha olefin polymerization, which is prepared by encapsulating a high molecular weight monomer in a mixture.

It is preferable that the melt index of the polypropylene polymer into which the long branch is used in this invention is 10-30 g / 10min (230 degreeC), and it is more preferable that it is 15-25 g / 10min (230 degreeC). If the melt index is less than 10 g / 10 minutes, the processing takes a lot of load, accompanied by a rapid pressure rise. When the melt index is 30 g / 10 minutes or more, the neck toughness and the weaving characteristic are poor with the decrease in the melt strength.

The polypropylene resin composition of the present invention is characterized in that when the strain rate has a value of a certain degree or more, the extension hardening phenomenon occurs and the stretch viscosity value becomes larger than that of the linear curve. .

To the polypropylene resin composition of the present invention, a known antioxidant known to be generally used in this kind of composition is added. The amount is preferably 0.1 to 1.0 parts by weight, and 0.3 to 100 parts by weight of polypropylene having long branches. 0.7 weight part is more preferable. If it is less than 0.1 part by weight, the antioxidant effect may be insufficient, and if it is more than 1.0 part by weight, the antioxidant effect reaches a certain level and does not increase any more.

To the resin composition of the present invention, various additives commonly used in extrusion-coated resin compositions, such as heat stabilizers, slip agents, neutralizers, and the like, can be added within a range not departing from the characteristics of the present invention.

The method for producing the resin composition of the present invention is not particularly limited, and a method for producing a polypropylene resin composition may be used. That is, the resin composition of the present invention is prepared by freely selecting the polypropylene resin and each additive component in which the long branch is introduced and kneading using a kneader such as a kneader, a roll, a chestnut mixer, or a single or twin screw extruder I can manufacture it.

Extrusion coating using the resin composition of the present invention is molded by a conventional T-die method, excellent in high-speed processing, neck toughness and excellent strength, can easily adjust the workability to the user BOPP thermal bonding, BOPP / CPP It can be applied for lamination and container coating.

The present invention can be understood in more detail by the following examples, the following examples are merely examples for illustrating the present invention and do not limit the protection scope of the present invention.

[Examples and Comparative Examples]

The measuring method of the physical property in each Example and a comparative example is as follows.

Melt Index Measurement

It measured at 230 degreeC and 2.16 kg based on ASTMD1238.

Melt strength and draw viscosity measurement

Melt strength at 140 ° C. chamber temperature for strands exiting through a plate of capillary rheometer at 200 ° C. using SMER (Samsung Melt Tension Rheometer) described in Patent Application Nos. 1999-8553 and 2001-30112, etc. The draw viscosity was measured. At this time, the L / D of the plate was 16, and the acceleration ratio was 1 mm / sec.

High Speed Machinability

The extruder was kept constant at 100 rpm and the coating speed was gradually increased to measure the rate at which breakage occurred.

Film width

The melt index from the T-die was coated on the OPP film to determine the coating width and determined as% of the T-die width. At this time, the processing temperature was 290 ° C and the T-Die width was 80 mm.

Adhesive

Using a BOPP film as the coating substrate, adhesion was evaluated by the T Peel test presented in ASTM D1876.

Weaving Speed

In order to evaluate the characteristics of the width change occurring during extrusion coating, a processing speed of 10% or more was measured.

Example 1

Long axis is introduced, the melt strength is 200mN, and the mixture is mixed with 0.5 parts by weight of antioxidant to 100 parts by weight of polypropylene having a melt index of 15.0 g / 10 min according to ASTM D1238 standard at 230 ° C. and 2.16 kg. Pelletized by melt mixing through an extruder. The physical properties of the resin composition were evaluated and shown in Table 1 below.

Comparative Example 1

Instead of the polypropylene of Example 1, the melt strength was 40mN, and the same as in Example 1 except that 100 parts by weight of polypropylene having a melt index of 15.0 g / 10 minutes in accordance with ASTM D1238 standard at 230 ℃, 2.16kg conditions Pelletizing and evaluation of the physical properties are shown in Table 1 below.

 Comparative Example 2

Instead of the polypropylene of Example 1, pelletized in the same manner as in Example 1 except that polypropylene having a melt strength of 20 mN and a melt index of 30.0 g / 10 min according to ASTM D1238 standard at 230 ° C. and 2.16 kg was used. And the physical properties were evaluated and shown in Table 1 below.

Melt Index [g / 10min] Melt strength [mN] Thickening phenomenon High Speed Machinability [m / min] Film width [%] Adhesive force [g] Weaving generation speed [m / min] Example 1 15.0 200 Expression 200> 88 404 Not Occurred Comparative Example 1 15.0 40 Not expressed 130 75 326 50 Comparative Example 2 30.0 20 Not expressed 180 62 317 70

In the resin composition according to the comparative example, the weaving phenomenon occurs, and the adhesion, high-speed workability and neck toughness are found to be inferior. According to the present invention, the melt tension is superior to that of the existing resin, and thus, the high-speed processability, thermal adhesion, and neck Polypropylene resin composition for extrusion coating excellent in toughness and weaving characteristics can be provided. In addition, it is possible to maintain the properties of the thermoplastic resin as it is possible to recycle.

Claims (4)

Long branch is introduced, the melt strength is 200mN or more, containing 200 parts by weight of polypropylene with a melt index of 10-30g / 10min according to ASTM D1238 standard at 2.16kg and 0.1 to 1.0 parts by weight of antioxidant Polypropylene resin composition characterized in that. The polypropylene resin composition according to claim 1, wherein the polypropylene has a melt index of 15 to 20.0 g / 10 minutes. The polypropylene resin composition according to claim 1, wherein the point severity phenomenon is expressed when the stretching viscosity of the polypropylene having the long branch is introduced.        The polypropylene resin composition according to any one of claims 1 to 3, wherein the resin composition is used for extrusion coating.