KR101316705B1 - Polyethylene film laminated by foam for packaging the display products - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene film inserted between respective products to protect a display screen during packaging and transportation of a display product. More particularly, the present invention relates to an electronic display product such as a liquid crystal display LCD TV, a monitor, a notebook computer, and the like. It relates to a laminated polyethylene protective film that can protect the screen from impact or external contamination during packaging and transportation. The present invention comprises a polyethylene layer consisting of three layers of an outer layer, a middle layer and an inner layer and a base layer bonded to the outer layer, wherein the outer layer is made of an outer layer forming composition containing low density polyethylene and linear low density polyethylene, wherein the middle layer is It consists of a middle layer forming composition containing at least two selected from the group consisting of low density polyethylene, linear low density polyethylene and high density polyethylene, the inner layer is made of an inner layer forming composition containing carbon nanotubes, low density polyethylene and linear low density polyethylene, And the base layer provides a polyethylene film of foam.

Description

Polyethylene film laminated by foam for packaging the display products}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene film inserted between respective products to protect a display screen during packaging and transportation of a display product, and more particularly, to an electronic display such as a liquid crystal display (LCD) TV, a monitor, a notebook, or the like. The present invention relates to a polyethylene protective film in which a foam is laminated to protect a screen from impact or external contamination during product packaging and transportation.

In general, electronic display products such as liquid crystal display (LCD) panels, plasma display panels, thin film transistor liquid crystal devices (TFT-LCDs), and OLEDs are subject to screen scratches during transportation, storage, and processing. Many screens are contaminated by foreign materials. In order to prevent such a problem, a protective film is attached to the screen of the electronic display product, and the electronic display is stored in a packaging bag for screen protection.

Currently, various types of foams are used to protect the screen of the display, and examples thereof include an electron beam crosslinking foam or a foam laminated with a coating film containing an antistatic agent.

The electron beam crosslinking foam is produced by crosslinking a polyolefin resin and a crosslinking agent compound after T-die extrusion. Such electron beam crosslinked foams have advantages of excellent chargeability and simplicity of production process, but are expensive to manufacture products, difficult to control uniform quality, and have poor pollutant properties.

Another conventional technique is a foam in which a film containing an antistatic agent is laminated. Korean Patent Publication No. 2011-0037353 discloses an antistatic horizontal laminated support for display glass. In the patent, the base sheet made of a foam made of crosslinked, chemical crosslinked, or electron beam crosslinking; And an antistatic layer laminated on one surface of the base sheet and formed of an extrusion coating antistatic composition containing carbon nanotubes. However, the laminated support has a problem in that the manufacturing process is complicated and the migration to the surface of the film occurs due to the process of extrusion coating the charging agent and the lamination process separately.

Accordingly, the present invention solves the problems described above, can be produced in a simple process as a film used in the packaging and transportation of display products, even in the absence of a protective film excellent antistatic properties damage to the display screen (Scratch) Without giving a poll-dirty phenomenon, it is an object of the present invention to provide a polyethylene film excellent in impact strength and shock-absorbing effect.

An object of the present invention as described above is a polyethylene film for display product packaging consisting of three layers of outer layer, middle layer and inner layer, wherein the outer layer is made of an outer layer forming composition containing low density polyethylene and linear low density polyethylene, Low density polyethylene, linear low density polyethylene, and a high density polyethylene comprising at least two selected from the group consisting of high density polyethylene, and the inner layer is composed of an inner layer forming composition containing carbon nanotubes, low density polyethylene and linear low density polyethylene It is achieved by a polyethylene film for foam lamination characterized in that.

Preferably, in the polyethylene film of the present invention, the outer layer forming composition contains 10 to 50 parts by weight of low density polyethylene and 40 to 80 parts by weight of linear low density polyethylene, and the middle layer forming composition is 20 to 50 parts by weight of low density polyethylene and linear low density polyethylene. 50 to 80 parts by weight, or 20 to 40 parts by weight of low density polyethylene, 20 to 50 parts by weight of linear low density polyethylene and 20 to 40 parts by weight of high density polyethylene, and the inner layer forming composition is 0.1 to 30 parts by weight of carbon nanotubes. 30 to 70 parts by weight of low density polyethylene and 20 to 50 parts by weight of linear low density polyethylene.

Preferably the outer layer forming composition further comprises ethylene vinyl acetate.

Preferably, the thickness of the outer layer, the middle layer and the inner layer is 10 to 40%, 30 to 70% and 10 to 40% of the total thickness of the entire polyethylene film, respectively.

In another aspect, the present invention is achieved by a foam laminated polyethylene film for display product packaging in which the polyethylene film is laminated on both sides of a base layer made of polyethylene foam.

In addition, the present invention is characterized in that the outer layer of the polyethylene film is laminated on both sides of the base layer.

Polyethylene film in which the foam of the present invention is laminated is composed of a process of coextrusion of each composition constituting the outer layer, the middle layer and the inner layer at the time of manufacture, and the process of laminating the base layer in the form of foam. Has the advantage of being lowered.

In addition, the foamed polyethylene film has a moderate hardness and excellent buffering effect, there is no migration of carbon nanotubes to the film surface, there is no stain and pol-dirty phenomenon, It has the advantage of excellent tensile strength and scratch resistance of the film.

Hereinafter, the polyethylene film laminated | stacked the foam used for the display product packaging of this invention is demonstrated in detail.

The polyethylene film of this invention consists of a polyethylene layer which consists of three layers of an inner layer, a middle layer, and an outer layer. In a preferred embodiment of the present invention, the polyethylene film is laminated on both sides of the base layer made of polyethylene foam to form a film for packaging display products.

In the polyethylene film of the present invention, the inner layer is composed of an inner layer forming composition containing carbon nanotubes, low density polyethylene and linear low density polyethylene. Preferably it consists of 0.1 to 10 parts by weight of carbon nanotubes, 30 to 60 parts by weight of low density polyethylene and 30 to 60 parts by weight of linear low density polyethylene.

In the present invention, in order to impart antistatic properties to the polyethylene film, it characterized in that it comprises a carbon nanotube in the inner layer. At this time, when the content ratio of carbon nanotubes to polyethylene exceeds 10 parts by weight, the dispersibility of the carbon nanotubes is lowered, and there is a problem of cost increase. Degrades.

The carbon nanotubes are selected from the group consisting of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, bundled carbon nanotubes, and mixtures thereof.

The inner layer is a portion attached to or abuts on the display screen when used between display products in the polyethylene film of the present invention, and is a layer which prevents the screen of the display from being contaminated or adhered to foreign matter. In the present invention, the carbon nanotubes are included in the inner layer to impart antistatic properties. Further, by using a mixture of low density polyethylene and linear low density polyethylene having different densities, the dispersibility of carbon nanotubes is improved, and excellent film properties are obtained. Low-density polyethylene has a low density to improve the dispersibility of carbon nanotubes, and because of the good bubble stability during film molding can maintain excellent film smoothness, and also can increase the thermal adhesive strength due to the low density. The linear low density polyethylene is somewhat inferior in bubble stability, but can maintain excellent film strength and thus maintain excellent thermal adhesive strength.

In this way, the inner polyethylene of the present invention is made of a combination of low density polyethylene and linear low density polyethylene, thereby providing excellent antistatic properties to the film, there is no transition phenomenon can prevent the fall-dirty phenomenon.

The middle layer is composed of a middle layer forming composition containing at least two selected from the group consisting of low density polyethylene, linear low density polyethylene, or high density polyethylene. Preferably it is 20 to 50 parts by weight of low density polyethylene and 50 to 80 parts by weight of linear low density polyethylene, or 20 to 40 parts by weight of low density polyethylene, 30 to 50 parts by weight of linear low density polyethylene and 20 to 40 parts by weight of high density polyethylene. . The middle layer is a layer that gives a harder texture and strength for easy handling when the polyethylene film of the present invention is sandwiched between display screens.

As such, the polyethylene in the middle layer of the present invention consists of a combination of low density polyethylene and linear low density polyethylene, or a combination of low density polyethylene, linear low density polyethylene and high density polyethylene, whereby the moderate stiffness of the film is increased so that Since the wear resistance can be increased, it is possible to prevent the phenomenon that stains caused by moisture on the display screen when stored under high temperature and high humidity. Low density polyethylene can maintain excellent film smoothness because it has good bubble stability during film molding. Linear low density polyethylene is somewhat inferior in bubble stability during film forming, but can maintain excellent film strength. In addition, high density polyethylene can increase stiffness due to its high density and can maintain proper heat resistance when laminating with foam, as well as maintain excellent heat adhesion.

The outer layer is composed of an outer layer forming composition containing low density polyethylene and linear low density polyethylene, preferably 10 to 50 parts by weight of low density polyethylene and 40 to 80 parts by weight of linear low density polyethylene. The outer layer is a layer laminated with foam in the packaging polyethylene film of the present invention, and facilitates lamination with foam so that peeling does not occur.

The outer layer may further include ethylene vinyl acetate, in which case ethylene vinyl acetate is preferably added 10 to 40 parts by weight based on the total weight of the outer layer composition. Ethylene vinyl acetate has a vinyl acetate functional group in terms of molecular structure compared to low density polyethylene, and when laminated with a base layer, it is excellent in low temperature heat sealing properties and thus may increase lamination strength. However, when the ethylene vinyl acetate exceeds 40 parts by weight, there is a problem in that the stickiness of the film surface is increased, which hinders the film smoothness, and the cost is increased to lower the economic efficiency.

Thus, it is preferable that the polyethylene of the outer layer of this invention consists of a combination of low density polyethylene and linear low density polyethylene. This allows the film to enhance adhesion and adhesion strength when laminating with the foam layer. Low density polyethylene has a low density and has good bubble stability during film forming, thereby maintaining excellent film smoothness and improving initial adhesion. In addition, the linear low density polyethylene is somewhat inferior in bubble stability when forming a film, but the strength of the film may be excellent, thereby increasing the adhesive strength.

The high density polyethylene has a melt index of 0.1 to 10 g / 10 min. And a density of 0.940 to 0.965 g / cm ³ .

The medium density polyethylene has a melt index of 0.1 to 10 g / 10 min. And a density of 0.926 to 0.940 g / cm ³ .

The linear low density polyethylene has a melt index of 0.1 to 10 g / 10 min. And a density of 0.910 to 0.925 g / cm ³ .

The low density polyethylene has a melt index of 1 to 10 g / 10 min. And a density of 0.918 to 0.923 g / cm ³ .

The ethylene vinyl acetate has a melt index of 1 to 10 g / 10 min., A density of 0.920 to 0.940 g / cm ³ , and a vinyl acetate content of 3 to 30%.

The base layer laminated with the polyethylene film is made of polyethylene foam prepared by crosslinking polyethylene-free crosslinking, chemical crosslinking, or electron beam crosslinking. In the present invention, an uncrosslinked foam can be preferably used. Non-crosslinked foam is made of polyethylene foam by injecting propane or butane gas while extruding in single extruder using low density polyethylene of 3 ~ 4 g / 10min Hanwha 5321 or LG BS 500

Since the base layer is formed of a foam, the base layer has a buffering force and a shock absorbing force to prevent breakage of the display screen by being positioned between the display panels when the product is packaged. In the present invention, the base layer is laminated on the outer layer of the polyethylene layer to impart a buffer property and an antistatic property to protect the display screen.

The polyethylene film laminated | stacked the base material layer of this invention is manufactured by the following method.

The first laminate is formed by passing a lamination roll to which the polyethylene film composed of the three layers described above and the substrate layer composed of the polyethylene foam are applied. At this time, the outer layer and the base material layer of the polyethylene film face each other and pass the lamination roll. Next, in the first laminated film, the second layer is laminated again by facing the outer layer of the polyethylene film including the base layer portion and the three layers. Finally, the polyethylene film is produced to the polyethylene film laminated on both sides of the base layer.

 In the foamed laminated polyethylene film for display product packaging of the present invention, the polyethylene film preferably has a thickness of 10 to 100 µm, more preferably 20 to 50 µm. In the polyethylene film, the thickness of the outer layer, the middle layer, and the inner layer is preferably 10 to 40%, 30 to 70%, and 10 to 40% relative to the total thickness of the film, respectively, 15 to 30%, 35 to 60%, and 15 to 15, respectively. More preferably, it is 30%. In addition, the substrate layer laminated with the polyethylene film is preferably 0.5mm ~ 10mm.

When the thickness of each layer is out of the above range, it is difficult to maintain proper antistatic properties, and it is difficult to adequately maintain the stiffness, strength and heat resistance of the film. There is a problem that the heat resistance falls apart and sticks together.

In addition, the outer layer forming composition, the middle layer forming composition and the inner layer forming composition has an anti-oxidant (Anti-oxidant) to prevent decomposition of the polyethylene resin (Polyethylene Resin) by high heat during film molding 0.01 to 100 parts by weight of each composition It may be added in an amount of 0.2 parts by weight. In addition to the lubricant and neutralizing agent may be further added in an amount of 0.01 to 0.03 parts by weight relative to 100 parts by weight of each composition.

Moreover, the manufacturing method of the polyethylene film of this invention,

The outer layer forming composition, the middle layer forming composition, and the inner layer forming composition are produced by a step of coextrusion. It is preferable to use a triple extruder for said coextrusion.

It is more expensive to invest in equipment than the single-stage extruder, and the film molding is somewhat difficult, but it is more preferable to use a triple and multiple extruders in order to impart functionality to each layer in the case of the functional film like the film for packaging a display product of the present invention.

The display product packaging film of the present invention contains carbon nanotubes (CNT) in the inner layer to impart a permanent antistatic property even in a small amount to prevent the incorporation of foreign objects and dust, and also prevents migration phenomenon from occurring. Gives the function that (Pol-dirty) does not occur.

In addition, in the case of the inner layer of the packaging film for display products, in order to enhance the stiffness and scratch resistance of the film itself, in consideration of the density characteristics of the polyethylene low density polyethylene and linear low density polyethylene 1: 1: 2 to 2: 1 It is preferable to comprise so that it may contain in ratio.

In addition, in the case of the middle layer of the display screen protection film of the present invention, in order to improve the stiffness and abrasion resistance of the film itself, low density polyethylene and linear low density polyethylene are used in consideration of the density characteristics of polyethylene 1: 3 to 3 :: It is particularly preferable to formulate to contain in a weight ratio of 1 or to contain low density polyethylene, linear low density polyethylene and high density polyethylene in a weight ratio of 3: 4: 3.

In addition, in the case of the outer layer of the packaging film for display products of the present invention, in order to improve the stiffness of the film itself and the bonding strength with the base layer, low density polyethylene and linear low density polyethylene in the range of 1: 3 to 3 in consideration of the density characteristics of the polyethylene; It was comprised so that it might contain in the weight ratio of 3: 1.

The three-layer composition is coextruded to produce a three-layer polyethylene film. Next, the polyethylene film and the base layer on which the foam is formed are laminated.

Specifically, the base paper made of the polyethylene film and the polyethylene foam is passed through a lamination roll to which heat is applied to form a primary lamination. At this time, the outer layer and the base material layer of the polyethylene film face each other and pass the lamination roll. Next, in the first laminated film, the second layer is laminated again by facing the outer layer of the polyethylene film including the base layer portion and the three layers. Finally, a foam laminated polyethylene film is used for packaging display products, in particular for sheeting.

Through consideration of each layer, the thermal characteristic gradient between layers was adjusted, which means that the physical properties required for the packaging of display products, namely impact mitigation properties, tensile strength, antistatic properties, pole-dirty, scratch resistance Its excellent physical properties make it possible to improve the commerciality of the film.

In addition, when the density, melt index, processing temperature (160 to 240 ° C.), and layer ratio of the polyethylene resin for each layer cannot be properly maintained, the appearance of the film, the deterioration of the film properties, and the curling phenomenon (Curling) -The phenomenon that the film curls) occurs, there is a disadvantage in that the commerciality and lamination properties as a film used as a slip sheet is inferior.

In addition, by using the polyethylene film for display packaging of the present invention, it is possible to manufacture a packaging bag in addition to the interleaf paper, which can be obtained by the conventional bag manufacturing process using the polyethylene film of the present invention described above.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples, but these Examples and the like are for illustrative purposes only and should not be construed as limiting the protection scope of the present invention.

Example  And Experimental Example

Example  One

Low Density Polyethylene (melt index 2.0 g / 10min, Density 0.923 g / cm ³ , LG BF 415, indicated below as “LDPE”) 48 wt% and linear low density polyethylene (melt Index 1.0 g / 10min, density 0.920 g / cm ³ , LG SP310, represented by "LLDPE" in the following table) 48% by weight, 4% by weight of carbon nanotubes were mixed and dispersed to prepare an inner layer forming composition,

50% by weight low density polyethylene (LDPE, melt index 2.0 g / 10min, density 0.923 g / cm ³ , LG BF 415) and 50% by weight linear low density polyethylene (melt index 1.0 g / 10min, density 0.920 g / cm ³ , SP310) Mixing and dispersing to prepare a layer forming composition,

40% by weight low density polyethylene (LDPE, melt index 2.0 g / 10min, density 0.923 g / cm ³ , LG BF 415), 40% by weight linear low density polyethylene (melt index 1.0 g / 10min, density 0.920 g / cm ³ , SP310) And 20 wt% ethylene vinyl acetate (EVA, melt index 1.8 g / 10 min, density 0.935 g / cm ³ , Hanwha 1316) was mixed and dispersed to prepare an outer layer forming composition,

A polyethylene film was prepared by coextrusion using a triple extruder using the three compositions. The thickness of the produced film was 30 μm, and the thickness ratio of the inner layer, the middle layer, and the outer layer was 1: 2: 1.

Next, using a low density polyethylene raw material of Hanwha 5321 or LG BS 500 having a melt index of 3 to 4 g / 10min, injection of propane or butane gas is performed to make a foamed foam, thereby preparing a base layer.

A polyethylene film for display packaging was prepared by laminating a three-layer polyethylene film on both sides of the substrate layer prepared above by lamination. At this time, the outer layer and the base layer of the polyethylene film faced. The temperature of the roll in the lamination step was 180 ~ 210'C and the pressure was 3 ~ 10kgf / cm².

Example  2 to 5

Except for preparing the inner layer forming composition, the middle layer forming composition and the outer layer forming composition according to the composition according to Table 1 below, a polyethylene film was laminated in the same manner as in Example 1 above. The figures in parentheses in the tables are in weight percent.

Comparative Example  One

80% by weight of high density polyethylene and 20% by weight of the permanent antistatic agent were mixed, and an outer layer antistatic film was prepared using a blown film extruder having a cylinder temperature of 200 to 250 ° C. The antistatic film and polyethylene non-crosslinked foam sheet thus prepared were passed through a roller to hot compress to prepare polyethylene foam slippers.

Experimental Example  One

For Examples 1 to 5 and Comparative Example 1 described above, the surface resistance of the film was measured by the method of ASTM D257-93.

Pole-Dirty exposed the film for 72 hours at 80 ° C. and 90% humidity conditions, then attached it to the display screen and artificially applied a constant load on the film to determine contamination on the surface condition of the screen.

The scratch resistance is determined by scratching the surface of the screen by attaching the film to the display screen and then rotating the weight with a constant load. At this time, the weight of the weight is gradually increased, and the weight of the weight Weight.

Tensile strength and elongation were measured according to the ASTM D 882 standard.

Stiffness is made of a film of 25mm in width, 100mm in length, and then bending the specimen in an oval shape and expressing the weight with constant enduring force.

Heat sealing strength was 120 ~ 150 ℃, after the heat-bonding under a time of about 1 second, the degree of peeling was visually confirmed.

The results are summarized in Table 2 below.

Referring to the above results, in terms of elongation and heat-sealing strength, it can be seen that Examples 1 to 5 of the present invention have almost the same results as Comparative Example 1, but the surface resistance is low to show excellent antistatic properties It can be seen that the folder and scratch resistance is excellently improved. The surface resistance of commercialized products is generally 109 Ω / sq or less, but in the case of internally-integrated polyethylene films, chargeability is inferior, which is a problem at present.

In order to compensate for this, HD film / foam / HD film is laminated after charging to maintain the chargeability of 109 / sq or less, but this also has a transfer problem and a transfer problem. The present invention solves this problem. In addition, in terms of tensile strength and elongation, it can be seen that Examples 1 to 5 of the present invention show a similar or even better effect than Comparative Example 1.

Claims (6)

A foam laminated polyethylene film for display product packaging consisting of three layers of outer layer, middle layer and inner layer,
The outer layer consists of an outer layer forming composition containing low density polyethylene and linear low density polyethylene,
The middle layer is made of a middle layer forming composition containing at least two selected from the group consisting of low density polyethylene, linear low density polyethylene, and high density polyethylene, and
The inner layer is a foam packaging polyethylene film for display packaging, characterized in that consisting of an inner layer forming composition containing carbon nanotubes, low density polyethylene and linear low density polyethylene. The method of claim 1,
The outer layer forming composition contains 10 to 50 parts by weight of low density polyethylene and 40 to 80 parts by weight of linear low density polyethylene,
The intermediate layer composition may contain 20 to 50 parts by weight of low density polyethylene and 50 to 80 parts by weight of linear low density polyethylene, or 20 to 40 parts by weight of low density polyethylene, 20 to 50 parts by weight of linear low density polyethylene and 20 to 40 parts by weight of high density polyethylene. Contains,
The inner layer forming composition is 0.1 to 10 parts by weight of carbon nanotubes, 30 to 70 parts by weight of low-density polyethylene, and 20 to 50 parts by weight of linear low-density polyethylene. The polyethylene film for display product foam laminate packaging of claim 1 wherein the outer layer forming composition further comprises ethylene vinyl acetate. The method of claim 1, wherein the thickness of the outer layer, middle layer and inner layer is 10 to 40%, 30 to 70% and 10 to 40% of the display product packaging foam laminated polyethylene film, respectively, characterized in that the total thickness of the polyethylene film. A foam laminated polyethylene film for packaging display products, wherein the polyethylene film of claim 1 is laminated on both sides of a base layer made of polyethylene foam. The foam laminated polyethylene film for packaging a display product according to claim 5, wherein the outer layer of the polyethylene film of claim 1 is laminated to both sides of the base layer.