KR100531256B1 - A oriented polypropylene film by coextrusion - Google Patents

Abstract

The present invention relates to a polyolefin-based coextruded biaxially stretched polypropylene film capable of extrusion coating without primer treatment, wherein the surface layer (I) co-extruded and laminated with a polypropylene resin (II) as a center layer is a polypropylene resin or a matte film. The adhesive layer (III) contacting the thermally laminated resin (IV) by using the composite resin for resin is 10 to 100% by weight of the polyethylene resin (A), 0 to 90% by weight of the polypropylene resin (B) and (A) and (B) It is composed by adding 0.05 to 2.O parts by weight of the processing aid (C) with respect to 100 parts by weight of the mixed resin, and is thermally laminated on the surface of the substrate such as papers, metals or films, and the surface of the book cover, calendar, shopping bag, poster, etc. It is used not only for protection but also for various packaging, and can be directly thermally laminated without primer treatment to minimize process loss and reduce cost, and to prevent risks and environmental pollution by using organic solvents. Effective on the side

Description

Polyolefin Co-Extrusion Stretched Polypropylene (OPP) Film {A oriented polypropylene film by coextrusion}

The present invention relates to a polyolefin-based coextruded stretched polypropylene film that can be extruded without primer treatment, and more specifically, to laminating films on substrates such as papers, metals, films, etc. without ethylene vinyl acetate (EVA), polyethylene It is to provide a stretched polypropylene film capable of extrusion coating and laminating low temperature resin.

In general, a method of laminating a film on a substrate such as paper, metal, film, etc. by applying an aqueous acrylic or oil-based adhesive to an oriented polypropylene film and passing through a drying apparatus to dry (lamination method) In addition to lamination, there is a thermal lamination method of melting and bonding low-temperature thermal adhesive resin.

The thermal lamination method again extrudes and oxidizes a low melting point heat adhesive resin at a high temperature of about 300 ° C. with or without a primer on a stretched polypropylene film, and gives polarity after pressing with other films and pressure rolls. After extruding lamination method and urethane-based or imine-based primer, the low-temperature heat-adhesive resin such as EVA (VA content 20%) is melt-extruded to 220 ℃ using extruder and then T-die 13 After coating, forming, and aging as thin as μm, it passes through the laminated film extruded and coated on steam roll heated to 95 ~ 100 ℃ by using a separate laminator so that it can be cut to a suitable size and laminated offline. There is a thermal lamination method of melting and laminating only low-temperature heat-adhesive resin layer and laminating with paper.

In particular, laminations such as book covers, shoes, shoes, cosmetics cases, calendars, shopping bags, and posters are made by laminating by adhesive and offline lamination by adhesive. Dry lamination by adhesive is suitable for mass production. It is necessary to use an adhesive coating facility and a drying facility to dry the adhesive. Most adhesives are not environmentally friendly, and there is a possibility of poor quality due to the invasion of the printing surface by residual solvents. Have.

On the other hand, the thermal lamination method can be thermally laminated offline, so that the installation space of the facility can be 1/2 times, and the high speed work is possible. However, if the adhesive strength with the polyethylene or EVA resin extruded on the OPP film is weak, there is a high possibility of peeling, especially in case of several folding cases, which may drop the product value. Extrusion coating has been caused but the productivity loss due to the process loss and raw material cost burden and has a problem of risk and environmental pollution due to the use of organic solvents.

The present invention has been made to solve the above problems, specifically, in laminating the film on the substrate, such as paper, metal, film, etc., extrusion coating and lamination of low-temperature resin such as ethylene vinyl acetate (EVA), polyethylene without primer treatment It is to provide a stretched polypropylene film that can be made.

It is a further object of the present invention to provide a sub-landing or masterbatch which can be used as the adhesive layer of the coextruded film according to the invention.

The structure of this invention makes polypropylene resin (II) the center layer, the surface layer (I) uses polypropylene resin or the composite resin for matte films, and the contact bonding layer (III) which contact | connects thermally laminated resin (IV) is the following ( It is to provide a coextrusion OPP film characterized by including the A) to (C) component.

(A): polyethylene resin

      10 to 100% by weight

(B): polypropylene resin

      0 to 90% by weight

(C): processing agent

      0.05 to 2.0 parts by weight based on 100 parts by weight of the mixture of (A) and (B)

In the present invention, the surface layer (I) is preferably a polypropylene having a relatively high melting point among the thermoplastic resins, and the polypropylene resin is commonly used to give a matting effect with a transparent type comprising a copolymer of propylene with at least one comonomer. It includes a matte type consisting of a composite resin composition for a matte laminated film, the total thickness is coextruded to 5 to 25% of the total film thickness.

In the present invention, the center layer (II) is preferably polypropylene, and the adhesive layer (III) in contact with the resin thermally laminated on the back side includes the components (A) to (C).

Polyethylene resins in the present invention include not only resins of homopolymers of ethylene but also resins of copolymers of ethylene and ethylenically unsaturated monomers.

The polyethylene resin as component (A) has a melting point of 50 to 130 ° C, for example, a low density to medium density high pressure polyethylene having a density of 0.900 to 0.935 g / cm 3, a linear low density polyethylene having a density of 0.880 to 0.940 g / cm 3, Linear polyethylene obtained by copolymerization using ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / alkyl acrylate copolymer, ethylene / methacrylic acid copolymer, metallocene catalyst, and for blocking resistance Linear low density polyethylene with a relatively high melting point is preferred.

These polyethylene resins may be used alone or in combination of two or more thereof, and may also be used within the mixing range of component (A) and component (B), but may be used alone as component (A) due to optical problems due to incompatibility. Can be.

In the present invention, the content of component (A) in the adhesive layer (III) is 10 to 100% by weight, preferably 50 to 100% by weight. In this case, when the content of component (A) is less than 10% by weight, the adhesive strength with the resin (IV) to be thermally laminated is weak and may be separated, which is not preferable, and problems such as blocking when the component (A) is used alone without using a processing aid. This is undesirable.

In other words, the resin used in the adhesive layer (III) has a lower melting point than polypropylene, which can stick to hot rolls during the stretching process, causing blocking or layer transition, and due to its poor transparency and poor optical properties when used with polypropylene, the melting point It is preferable to mix a processing aid with a linear low density polyethylene resin alone which is high and has excellent heat resistance.

In the present invention, the processing aid is added to modify the film surface for the purpose of anti-blocking, anti-static, slip reinforcement, and may be selected alone or two or more, and as a specific compound, synthetic silica-based, organic A PMMA type | system | group or a silicone type resin is mentioned, A quaternary ammonium salt, an alkyl amine, a glycerol compound, etc. can be used as an antistatic agent. In addition, the slip agent used for the surface lubrication effect by reducing the friction coefficient may be used fatty acid amide, for example, Eruamide, Oleamide, Steamide is mainly used.

At this time, the content of the processing aid is preferably used within the range of 0.05 parts by weight to 2.0 parts by weight with respect to 100 parts by weight of the mixture of the resin of the (A) component and the resin of the (B) component, the content of 0.05 parts by weight (10 When less than 0.5% = 500 ppm) of the masterbatch, the effect as a processing aid is insignificant, and when it exceeds 2 parts by weight (20,000 ppm), the optical properties of the entire film are adversely affected, more preferably 0.1 to 0.5 parts by weight.

The thickness of the adhesive layer having the composition according to the invention is 5 to 25%, preferably 10 to 20% of the total film thickness. If the thickness of the adhesive layer is less than 5% of the total film thickness, the appearance is poor due to the occurrence of surging, and if the thickness is 25% or more, the film is too soft and blocking is likely to occur.

Coextruded through each extruder in the configuration as described above to produce a draw roll after cooling to 20 ~ 45 ℃ or in water. The sheet was stretched about 4.5 times in the longitudinally stretched region at about 100 to 140 ° C. and then stretched 7 times in the transversely stretched region at 150 to 180 ° C. to produce a coextruded film having a size of 10 to 50 μm.

In addition, in the film according to the present invention, the branding material or masterbatch used for forming the adhesive layer (III) has a low to medium density high pressure polyethylene having a melting point of 50 to 130 ° C. and a density of 0.900 to 0.935 g / cm 3, density. Linear low density polyethylene, ethylene / vinylacetate copolymer, ethylene / acrylic acid copolymer, ethylene / alkyl acrylate copolymer, ethylene / methacrylic acid copolymer, metallocene catalyst 10 to 100% by weight of one (A) selected from the obtained linear polyethylenes; It is comprised from 0.05-2.0 weight part of processing aids (C) with respect to 0 to 90 weight% of polypropylene resins (B) and 100 weight part of mixtures of (A) and (B).

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

A homopolypropylene (Hyosung E Grade) having a melt index (MI) of 2.0 g / 10min is used as the center layer (II), and a homopolypropylene (LG petrochemical H Grade) having a melt index of 4.0 g / 10min is used for the surface layer (I). In the adhesive layer (III), linear low-density polyethylene (Hyundai Petrochemical S Grade) having a melt index of 5.0g / 10min and 0.2 wt% of organic PMMA system (10% masterbatch = 2000ppm) were used as a processing aid, and each extruder was used. The surface layer and the adhesive layer were each co-extruded to 240 ℃ to 10%, respectively, to prepare a non-stretched sheet after cooling in water at 30 ℃. The sheet was stretched about 4.5 times in the longitudinal stretch region of about 112 to 125 DEG C, and then stretched 7 times in the transverse stretch region of 158 to 175 DEG C to prepare a transparent OPP film having a thickness of about 15 mu m.

EVA (20% VA content) to the adhesive layer of the film melt extruded at 220 ℃ using an extruder and then thinly coated to 13㎛ by T-die to about 13㎛ thin cut to a suitable size and then offline to separate By passing the laminated film extruded through a steam roll heated to 100 ℃ by using to melt only the low-temperature heat adhesive resin layer was fused with paper, laminated to prepare a laminate.

The laminated paper was folded and folded five times, and then the degree of peeling with the paper was measured.

Example 2

It is the same as Example 1 except the surface layer (I) composition being a matte composite resin masterbatch (Korean emulsified L Grade) and having a thickness of 18 µm.

Example 3

The surface layer (I) composition is the same as that of Example 1 except having set the matte composite resin masterbatch (Segong grade) manufactured by Seotong Co., Ltd., and thickness to 18 micrometers.

Comparative Example 1

It was prepared in the same manner as in Example 1 except that the processing aid (C) was not used in the adhesive layer (III) resin composition.

Comparative Example 2

In the same manner as in Example 1, except that the surface layer (I) resin as in Example 1 was used as in the conventional adhesive layer (III) resin.

Comparative Example 3

The same procedure as in Comparative Example 2 was conducted except that the conventional imine-based primer was treated to a thickness of 0.1 μm on the adhesive layer (III) resin layer.

The physical properties of the films prepared by Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1.

Example 1 (15 μm) Example 2 (18 μm) Example 3 (18 μm) Comparative Example 1 (15 μm) Comparative Example 2 (15 μm) Comparative Example 3 (15 μm) OPP Fabric Haze (%) (surface layer) 1.6 70 70 1.5 1.5 1.5 Gloss (%) (adhesive layer) 100 70 70 100 100 100 Gloss (%) (surface layer) 98 70 70 100 100 100 Coefficient of friction (surface layer) 0.4 0.25 0.25 0.4 0.4 0.4 Friction Coefficient (adhesive layer) 0.6 0.6 0.6 1.2 0.4 0.4 OPP / EVA EVA peel strength (g / 15mm) Not separated Not separated Not separated Not separated 20 110 OPP / EVA / Paper Paper strength with paper Good Good Good Good Bad Good

Property measurement method

1) Melt Index (g / 10min)

According to ASTM D1238, polypropylene is a measure of the amount of resin exiting through a nozzle for 10 minutes under a 2.16 kg load at 230 ° C., and polyethylene is measured at 2.16 kg at 190 ° C. equally.

2) Blur (%)

It is measured by ASTM D1003.

3) glossiness

According to ASTM D2457, the incident angle of light and the measured angle were measured at 45 °.

4) Thickness of Matte Layer (㎛)

The thickness of the matte layer was measured by SEM (Scanning Electron Microscope).

5) EVA layer peeling degree

Specimen was taken in 15 mm width using a tensile tester and subjected to a 90 ° peel test at a speed of 300 mm / min.

6) paper strength with paper

After lamination and folding five times after lamination with paper was measured the degree of peeling with the paper.

As described above, when extruded and laminated thermally laminated resins such as polyethylene and EVA on a matt or transparent type OPP film, thermal lamination can be directly performed without primer treatment, thereby minimizing process loss and reducing costs. It is effective in preventing environmental pollution.

Claims (4)

In the film composed of polypropylene resin as the center layer (II) and coextrusion of the surface layer (I) and the adhesive layer (III), the melting point of the adhesive layer (III) is 50 to 130 ° C. and the density is 0.900 to 0.935 g. One or two or more mixtures (A) and mixtures selected from low to medium density high pressure polyethylenes / cm 3, linear low density polyethylenes having a density of 0.880 to 0.940 g / cm 3, linear polyethylenes obtained by copolymerization using metallocene catalysts (A) Co-extrusion oriented polypropylene (OPP) film, Comprising: 0.05 to 2.0 parts by weight of the processing aid (C) per 100 parts by weight. The polypropylene resin according to claim 1, wherein the polypropylene resin used in the surface layer (I) is a transparent type comprising a homopolypropylene, a copolymer of propylene and at least one comonomer, or a matte type using a composite resin for a matte laminated film. A coextruded stretched polypropylene (OPP) film, characterized by the above-mentioned. The coextruded stretched polypropylene (OPP) film according to claim 1, wherein the processing aid is one kind or a mixture of two or more kinds selected from an antiblocking agent, an antistatic agent and a slip reinforcement agent. From low to medium density high pressure polyethylene having a melting point of 50 to 130 ° C., density of 0.900 to 0.935 g / cm 3, linear low density polyethylene having a density of 0.880 to 0.940 g / cm 3, linear polyethylene obtained by copolymerization using a metallocene catalyst A master batch for producing an adhesive layer (III), comprising 0.05 to 2.0 parts by weight of the processing aid (C) based on one or more selected mixtures (A) and 100 parts by weight of the mixture (A).