KR19990024631A - Polymer composition comprising a blend of ethylene-vinyl alcohol copolymer and nylon, and method for producing a packaging film using the same - Google Patents

Abstract

The present invention relates to a polymer composition comprising a blend of a polyolefin, an ethylene-vinyl alcohol copolymer and nylon, and a compatibilizer, and a method for producing a packaging film using the same. The polymer composition of the present invention comprises 60 to 95% by weight of polyolefin, 5 to 35% by weight of a blend of ethylene-vinyl alcohol copolymer and nylon, and 1 to 15% by weight of a compatibilizer, and may be used as a material for a packaging film. According to the present invention, an ethylene-vinyl alcohol copolymer and nylon are mixed or mixed and melt mixed to prepare a dry or melt blend, and a polyolefin, a dry or melt blend of an ethylene-vinyl alcohol copolymer and nylon prepared in an electrical process And a compatibilizer are mixed and processed and stretched using a screw extruder with a circular blown film die to prepare a packaging film. The polymer composition of the present invention not only has excellent barrier properties against gases including oxygen and organic solvents such as toluene, but also has excellent mechanical properties such as tensile strength, tensile modulus and elongation, and is economical.

Description

Polymer composition comprising a blend of ethylene-vinyl alcohol copolymer and nylon, and method for producing a packaging film using the same

The present invention relates to a polymer composition comprising a blend of a polyolefin, an ethylene-vinyl alcohol copolymer and nylon, and a compatibilizer, and a method for producing a packaging film using the same. More specifically, the present invention provides 60 to 95% by weight of polyolefin having excellent barrier properties and mechanical properties to various gases and organic solvents, 5 to 35% by weight of a blend of ethylene-vinyl alcohol copolymer and nylon, and commercialization. It relates to a polymer composition comprising 1 to 15% by weight and a method for producing a packaging film using the same.

Polyolefin has been used as a packaging material because of its high barrier property against liquids containing water and an extremely limited number of organic solvents, and excellent processability, economy and stability. However, the barrier properties to various gases (oxygen, carbon dioxide, fragrance) and some organic solvents are low, and the range of use as a packaging material is extremely limited. Therefore, in order to solve the disadvantage of the polyolefin, blending resins having excellent barrier properties such as ethylene-vinyl alcohol copolymer (EVOH, ethylene-vinyl alcohol copolymer), nylon (nylon) or polyvinylidene chloride (polyvinylidene chloride) Research on the development of packaging materials laminated or laminated has been continued.

For example, US Pat. Nos. 4, 410, 482 and 4, 444, 817 disclose the use of liquid hydrocarbons as containers including laminated articles of polyolefins and nylon with excellent barrier properties and their fuel tanks for automobiles. It is. However, the electrical layer article has a problem of low shielding against gas flows, especially oxygen gas.

On the other hand, European Patent Publication No. 15556 discloses a laminated article of polyolefin and polyvinyl alcohol or ethylene-vinyl alcohol copolymer having excellent barrier properties. However, the electrically laminated articles have improved barrier properties against gases and hydrocarbons, but have a problem that the price is quite expensive and the elongation is low. Therefore, there is an urgent need to develop a packaging material having excellent barrier properties and mechanical properties to various gases and hydrocarbons as well as economical efficiency.

Accordingly, the present inventors have made diligent efforts to solve the problems of the packaging materials including the conventional polyolefin and ethylene-vinyl alcohol copolymer or nylon, and as a result, dry blending of the polyolefin, ethylene-vinyl alcohol copolymer and nylon resin ( It is confirmed that the polymer composition including the blend and the compatibilizer prepared by dry blending or melt blending has excellent barrier properties and mechanical properties to various gases and hydrocarbons, as well as being economical. To complete.

After all, it is an object of the present invention to provide a polymer composition comprising a blend of a polyolefin, an ethylene-vinyl alcohol copolymer and nylon, and a compatibilizer.

Another object of the present invention to provide a method for producing a packaging film using the polymer composition.

Hereinafter, a polymer composition comprising a blend of a polyolefin, an copolymer of ethylene-vinyl alcohol and nylon, and a compatibilizer according to the present invention, and a method for producing a packaging film using the same will be described in more detail.

The polymer composition of the present invention comprises 60 to 95% by weight polyolefin, 5 to 35% by weight blend of ethylene-vinyl alcohol copolymer and nylon and 1 to 15% by weight compatibilizer.

As the polyolefin, polyolefin, polypropylene, polybutylene, and the like are used. Among them, polyolefin is most preferable, and high density, medium density or low density polyolefin can be used. The blend of ethylene-vinyl alcohol copolymer and nylon is 5 to 95% by weight of ethylene-vinyl alcohol copolymer, preferably 40 to 80% by weight and 5 to 95% by weight of nylon, preferably 20 to 60% by weight of drying. Or melt blends are used, of which melt blends are more preferred. On the other hand, the ethylene-vinyl alcohol copolymer is preferably a hybrid copolymer of 25 to 40% by weight of ethylene and 60 to 75% by weight of vinyl alcohol, and nylon 6 or nylon 66 is preferable as the nylon. As the compatibilizer, an alkylcarboxyl-substituted polyolefin having a monomer containing 0.1 to 5% by weight of a carboxyl moiety in the polyolefin main chain or branched chain is used. In this case, the monomer including the carboxyl moiety means acid, ester, anhydride, or salt having a double bond, and specific examples thereof include fumaric acid or maleic anhydride. Polyethylene, polypropylene, polybutylene and the like are used, of which polyethylene is most preferred, and high density, medium density or low density polyethylene is possible. The most preferred example of an electrical compatibilizer is linear low density polyethylene grafted with 0.15 wt. Maleic anhydride.

Referring to the manufacturing method of the packaging film using the polymer composition of the present invention according to the process as follows:

Step 1: Preparation of the Blend

In the case of a dry blend, 5 to 95% by weight, preferably 40 to 80% by weight of ethylene-vinyl alcohol copolymer and 5 to 95% by weight of nylon, preferably 20 to 60% by weight, are prepared by mixing at room temperature and atmospheric pressure. In the case of a melt blend, 5 to 95% by weight of ethylene-vinyl alcohol copolymer, preferably 40 to 80% by weight and 5 to 95% by weight of nylon, preferably 20 to 60% by weight are mixed at room temperature and atmospheric pressure. , Prepared by melt mixing at the melting point of the nylon (melting point) or more. At this time, the melt mixing is carried out using a twin screw extruder, 200 to 240 ℃ (zone 1) -210 to 250- ℃ (zone 2) -220 to 260 ℃ (zone 3) -220 to 260 ℃ (die ( die)) and a rotational speed of 20 to 60 rpm.

Second Step: Preparation of Packaging Film

60-95 weight percent polyolefin, 5 to 35 weight percent blend of nylon and ethylene-vinyl alcohol copolymer prepared in the above process, and 1 to 15 weight percent compatibilizer, and a screw extruder with a circular blown film die It is processed at a processing temperature of 160 to 200 ° C (zone 1) -200 to 240 ° C (zone 2) -220 to 260 ° C (die) and a rotational speed of 40 to 80 rpm, and stretched to prepare a packaging film.

In the former, it is preferable to use a low shear and low mixing single screw extruder to minimize homogenization of the molten mixture as the screw extruder. In addition, either uniaxial or biaxial stretching is possible.

The packaging film prepared using the polymer composition of the present invention has a plurality of thin, two-dimensional, parallel and overlapping lamellar morphologies in which a blend of ethylene-vinyl alcohol copolymer and nylon, which is a dispersed domain, in a polyolefin, which is a continuous phase, is nylon. ) And compatibilizers are evenly distributed at the interface between the polyolefin and the blend to maintain the shape of the plate-like structure. In this case, when the electric blend is a dry blend, each of the ethylene-vinyl alcohol copolymer and nylon is present as a separate dispersed phase, and exhibits a substantially linearly proportional physical property to the relative weight of each resin. In this case, as the blend itself, it exists as one dispersed phase and exhibits physical properties independent of each resin.

Hereinafter, the present invention will be described in more detail with reference to Examples.

These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited to these examples according to the gist of the present invention.

Example 1

Preparation of Packaging Films Containing Dry Blend of Ethylene-Vinyl Alcohol Copolymer and Nylon (I)

75% by weight and density of copolymer of 32 mol% ethylene and 68 mol% vinyl alcohol (Kuraray Co., Ltd., Japan) having a density of 1.19 g / cm 3 and a melt of 1.3 g / 10 min in a polyethylene bag A dry blend of ethylene-vinyl alcohol copolymer and nylon 6 was prepared by mixing 25 wt% of nylon 6 (Dongyang Nylon Co., Ltd., Korea) having a value of 1.14 g / cm 3 at room temperature and atmospheric pressure. Next, 74.1% by weight of low density polyethylene (LG Chemical Co., Ltd.) with a density of 0.922 g / cm 3 and a melt index of 0.3 g / 10 min., 18.5 weight of dry blend of ethylene-vinyl alcohol copolymer and nylon 6 prepared before. % And 7.4 wt% of linear low density polyethylene (Mitsui Petrochemical Industries Ltd., Japan) grafted with 0.1 wt% maleic anhydride with a melt index of 6.2 g / 10 min. Then, using a single screw extruder (L / D = 20, Brabender Plasticorder-3 / 4 inch, Germany) with a circular blown film die (inner diameter = 75.4 mm, die gap thickness = 1 mm), 180 ° C. ( The packaging film was produced by biaxial stretching by processing at a processing temperature of zone 1) -220 ° C. (zone 2) -240 ° C. (die) and a rotational speed of 60 rpm.

Example 2

Preparation of Packaging Films Containing Dry Blend of Ethylene-Vinyl Alcohol Copolymer and Nylon (II)

A packaging film was prepared in the same manner as in Example 1, except that 50% by weight of the ethylene-vinyl alcohol copolymer and 50% by weight of nylon 6 were mixed.

Example 3

Preparation of Packaging Films Containing Dry Blend of Ethylene-Vinyl Alcohol Copolymer and Nylon (III)

A packaging film was prepared in the same manner as in Example 1, except that 25% by weight of the ethylene-vinyl alcohol copolymer and 75% by weight of nylon 6 were mixed.

Comparative Example 1

Preparation of Packaging Films Containing Ethylene-Vinyl Alcohol Copolymer

A copolymer of 74.1% by weight of low density polystyrene having a density of 0.922 g / cm 3 and a melt index of 0.3 g / 10 min, and 68 mol% of ethylene 32 mol% vinyl alcohol having a density of 1.19 g / cm 3 and a melt index of 1.3 g / 10 min. 18.5 wt% and 7.4 wt% of linear low density polyethylene grafted with 0.1 wt% maleic anhydride with a melt index of 6.2 g / 10 min. Then, using a single screw extruder with a round blown film die, a processing temperature of 180 ° C. (zone 1) 220 ° C. (zone 2) -240 ° C. (die) and rotation of 60 rpm The film was processed at a speed and biaxially stretched to prepare a packaging film.

Comparative Example 2

Preparation of Packaging Films Containing Nylon

A packaging film was prepared in the same manner as in Comparative Example 1, except that Nylon 6 having a density of 1.14 g / cm 3 was mixed instead of the ethylene-vinyl alcohol copolymer.

Example 4

Measurement of Permeability and Mechanical Properties (I)

Oxygen permeability of the packaging films prepared in Examples 1 to 3 and Comparative Examples 1 and 2, respectively, at 30 ° C. based on a known time lag method (see WZ Zhang et al. , J. Memb Sci., 31: 147 (1987)), and the toluene permeability was self-made permeation apparatus by a known method at 30 ° C. (SY Lee and SC Kin, The Korean J. Rheology, 5: 125 (1993)), and tensile strength, tensile modulus and elongation were measured according to ASTM D-882 using a universal tensile tester (Instron, Model 4202, USA). It is shown in Table 1 below.

Table 1: Permeability and Mechanical Properties

a: machine direction of film

b: transverse direction of film

As shown in Table 1, the packaging film including the ethylene-vinyl alcohol copolymer and the nylon dry blend of the present invention has a lower oxygen permeability than the packaging film including nylon 6 prepared in Comparative Example 2, tensile strength and Tensile modulus is large and elongation is large compared with the packaging film containing the ethylene-vinyl alcohol copolymer manufactured in the comparative example 1. That is, the packaging film comprising the dry blend of ethylene-vinyl alcohol copolymer and nylon of the present invention is approximately linearly proportional to the relative weight of each resin, and it can be seen that it has excellent oxygen barrier properties and mechanical properties as a whole. there was.

Example 5

Preparation of Packaging Films Containing Melt Blend of Ethylene-Vinyl Alcohol Copolymer and Nylon (I)

32 mol% of ethylene with a density of 1.19 g / cm3 and 1.3 g / 10 min of molten resin and 75% by weight of 68 mol% of vinyl alcohol and 25% by weight of nylon 6 having a density of 1.14 g / cm3 were mixed at room temperature and atmospheric pressure. Using a twin screw extruder (L / D = 20, 19, Bribendish, Germany), 220 ° C (zone 1) -230 ° C (zone 2) -240 ° C (zone 3) -240 ° C (die ( die) and melt blended at a processing temperature of 40 rpm and a rotational speed of 40 rpm to prepare a melt blend of ethylene-vinyl alcohol copolymer and nylon 6. Subsequently, instead of the dry blend of ethylene-vinyl alcohol copolymer and nylon 6, the mixture was prepared in the past. A packaging film was prepared in the same manner as in Example 1, except that a melt blend of ethylene-vinyl alcohol copolymer and nylon 6 was used.

Example 6

Preparation of Packaging Films Containing Melt Blend of Ethylene-Vinyl Alcohol Copolymer and Nylon (II)

A packaging film was prepared in the same manner as in Example 5, except that 50% by weight of ethylene-vinyl alcohol copolymer and 50% by weight of nylon 6 were mixed.

Example 7

Preparation of Packaging Films Containing Melt Blend of Ethylene-Vinyl Alcohol Copolymer and Nylon (III)

A packaging film was prepared in the same manner as in Example 5, except that 25% by weight of the ethylene-vinyl alcohol copolymer and 75% by weight of nylon 6 were mixed.

Example 8

Measurement of Permeability and Mechanical Properties (II)

Oxygen permeability, toluene permeability, tensile strength, tensile modulus and elongation of the packaging films prepared in Examples 5 to 7, respectively, were measured in the same manner as in Example 4, and the results were compared with the measured values of Comparative Examples 1 and 2. The comparison is shown in Table 2 below.

Table 2: Permeability and Mechanical Properties

a: machine direction of film

b: transverse direction of film

As shown in Table 2, the oxygen permeability of the packaging film comprising a melt blend of the ethylene-vinyl alcohol copolymer prepared in Examples 5 to 7 and nylon is added to the packaging film comprising nylon 6 prepared in Comparative Example 2. It is smaller than that, and in particular, the oxygen permeability of the packaging film prepared in Example 5 is smaller than that of the packaging film prepared in Comparative Example 1 containing an ethylene-vinyl alcohol copolymer. In addition, the toluene permeability of the packaging film containing the melt blend of the ethylene-vinyl alcohol copolymer prepared in Examples 5 to 7 and nylon was smaller than that of the packaging film containing nylon 6 prepared in Comparative Example 2, and in particular, The toluene permeability of the packaging films prepared in Examples 5 and 6 is smaller than the packaging films prepared in Comparative Example 1 containing an ethylene-vinyl alcohol copolymer.

In addition, the tensile strength and the elongation of the packaging films prepared in Examples 5 to 7 are larger than those of the packaging films prepared in Comparative Examples 1 and 2, and the tensile elastic modulus of the packaging films prepared in Examples 5 to 7. Is larger than the packaging film prepared in Comparative Example 2.

Therefore, it was found that the oxygen barrier properties and mechanical properties of the packaging film including the melt blend of the ethylene-vinyl alcohol copolymer and nylon of the present invention were very excellent overall. In particular, it can be seen that a film containing a melt blend of ethylene-vinyl alcohol copolymer and nylon is superior in oxygen barrier properties and mechanical properties than a packaging film comprising a dry blend of ethylene-vinyl alcohol copolymer and nylon. there was.

As described and demonstrated in detail above, the present invention provides a polymer composition comprising a blend of a polyolefin, an ethylene-vinyl alcohol copolymer and nylon, and a compatibilizer, a packaging film using the same, and a method of manufacturing the same. The polymer composition of the present invention not only has excellent barrier properties against gases including oxygen and organic solvents such as toluene, but also has excellent mechanical properties such as tensile strength, tensile modulus, and elongation. to be. Accordingly, the polymer composition of the present invention can be used as a material for packaging films, or as one or more layers of laminated articles.

Claims (11)

60 to 95 weight percent polyolefin, with ethylene-vinyl alcohol copolymer A polymer composition comprising 5 to 35 weight percent blend of nylon and 1 to 15 weight percent compatibilizer. The method of claim 1, Polyolefin is characterized in that the polyethylene, polypropylene or polybutylene Polymer composition. The method of claim 1, The blend of ethylene-vinyl alcohol copolymer and nylon is a dry blend of 5 to 95% by weight of ethylene-vinyl alcohol copolymer and 5 to 95% by weight of nylon. Polymer composition. The method of claim 1, The blend of ethylene-vinyl alcohol copolymer and nylon is a melt blend of 5 to 95% by weight of ethylene-vinyl alcohol copolymer and 5 to 95% by weight of nylon. Polymer composition. The method of claim 1, The compatibilizer is an alkylcarboxyl-substituted polyolefin in which 0.1 to 5 wt. 5 monomers containing a carboxyl moiety in a polyolefin main chain or a branched chain are bonded. Polymer composition. The method of claim 5, The monomer comprising the carboxyl moiety is characterized in that it is fumaric acid or maleic anhydride. Polymer composition. (i) mixing a ethylene-vinyl alcohol copolymer with 5 to 95% by weight of nylon and 5 to 95% by weight to prepare a blend of ethylene-vinyl alcohol copolymer and nylon; (ii) 60 to 95% by weight of polyolefin, 5 to 35% by weight of blend of ethylene-vinyl alcohol copolymer and nylon prepared in the above process and 1 to 15% by weight of compatibilizer, mixed with a circular blown film die A method for producing a packaging film comprising a step of processing and stretching using a screw extruder. The method of claim 7, wherein The ethylene-vinyl alcohol copolymer and nylon are mixed at room temperature and atmospheric pressure to prepare a dry blend of ethylene-vinyl alcohol copolymer and nylon. Method for producing a packaging film. The method of claim 7, wherein Ethylene-vinyl alcohol copolymer and nylon are mixed at room temperature and atmospheric pressure, and using a twin screw extruder, 200 to 240 ° C (zone 1) -210 to 250 ° C (zone 2) -220 to 260 ° C (zone 3) melt mixing at a processing temperature of -220 to 260 ℃ (die) and a rotational speed of 20 to 60rpm to produce a melt blend of ethylene-vinyl alcohol copolymer and nylon Method for producing a packaging film. The method of claim 7, wherein The screw extruder is a single screw extruder, and the processing conditions are 160 to 200 ° C. (zone 1) -200 to 240 ° C. (zone 2) -220 to 260 ° C. (die) and a 40 to 80 rpm rotation. Characterized in that the speed Method for producing a packaging film. A packaging film produced by the method of claim 7.