KR102091593B1 - Recyclable laminated films and ECO-friendly roll-bags, disposable tablecloths and disposable gloves from them - Google Patents

Abstract

The present invention relates to a recyclable laminated film in which a polyethylene recycled resin (waste polyethylene resin recycled raw material) film layer and a polyethylene-based crystallized film layer having a crystallinity of 80% or more laminated on both sides thereof are laminated. The film is a recyclable laminated film with excellent mechanical properties and compatibility as a food packaging material, even with polyethylene recycled resin, and thus can be used for eco-friendly roll bags, disposable tablecloths, disposable gloves, etc.

Description

Recyclable laminated films and ECO-friendly roll-bags, disposable tablecloths and disposable gloves from them}

The present invention relates to a resource-cycling (recyclable) laminated film and an eco-friendly rollback obtained from it, a disposable tablecloth and a disposable glove, and more specifically, excellent mechanical properties even using polyethylene recycled resin (recycled polyethylene resin recycled raw material). It is to provide a resource-recyclable laminated film having physical properties and a suitable food packaging material, an eco-friendly rollback obtained from it, a disposable tablecloth, and a disposable glove.

Disposable tablecloths placed on the table where foods contained in rolls, plates, and bowls, which are widely used as food packaging materials for vegetables, fish, etc., which are particularly easy to get wet when shopping, and disposables used for cooking, dipping kimchi, etc. As a glove, a film molded of polyethylene resin, which has excellent water resistance, excellent mechanical properties and compatibility as a food packaging material and is inexpensive, has been widely used.

Normally, the quality of rollback, disposable tablecloth and disposable gloves is evaluated according to the quality assurance Q mark standard.The mechanical properties require tensile strength of 12MPa or more and tensile elongation of 150% or more, and also require suitability as a food packaging material. Doing.

The suitability as the food packaging material is in accordance with the standards and specifications of the Agency for Food and Drug Administration and packaging and containers. For example, 1) lead 1 (mg / L) or less, 2) potassium permanganate consumption 10 (mg / L) or less, 3 ) It is required that the total elution amount is 30 (mg / L) or less.

However, rollback made of polyethylene film, disposable tablecloth, disposable gloves, etc. are excellent products in terms of quality and economical efficiency, but have been used as a typical disposable product, and have been a big environmental problem due to landfill and incineration treatment when discarded.

As an alternative to this, rollbacks made of films molded from biodegradable resins such as polylactic acid, disposable tablecloths and disposable gloves have been suggested, but mechanical properties are weak and cost is comparable to rollbacks made of polyethylene film, disposable tablecloths and disposable gloves. Not only is it very expensive, about 4 to 5 times, but also biodegradability usually shows its eco-friendliness only when it is disposed of after disposal. In Korea, Japan and Europe, most of them are incinerated without landfill. The emergence of was desperate.

As another alternative, a roll of a film molded from a mixture of polyethylene recycled resin and a new polyethylene resin, disposable tablecloth, disposable gloves, etc. have been suggested. It is difficult to use due to its weak physical properties. Moreover, when the polyethylene recycled resin is used in excess of the same amount as the new polyethylene resin, the mechanical properties cannot be satisfactorily satisfied and the suitability as a food packaging material is greatly impaired. This became desperate.

In particular, the Act on the Conservation of Resources and the Promotion of Recycling requires that recycled resin content is 50% by weight or more in the case of film products, so even though polyethylene recycled resin content is added by more than 50% by weight, it has excellent mechanical properties and food packaging. The emergence of new technologies for manufacturing eco-friendly resource-recycling films with suitability and rollbacks, disposable tablecloths, disposable gloves, and the like, is urgently requested.

Accordingly, the present invention is to provide an environmentally friendly resource-cycling laminated film having excellent mechanical properties and compatibility as a food packaging material even when the polyethylene recycled resin is used in the same or excess amount than the new polyethylene resin.

Another object of the present invention is to provide a method for producing a laminated film for industrially advantageously producing the laminated film of the present invention with good productivity.

Another object of the present invention is to provide an eco-friendly rollback, disposable tablecloth and disposable gloves utilizing various characteristics of the laminated film of the present invention.

In order to achieve the above object, the present invention can achieve the above object by manufacturing a polyethylene recycled resin film layer and a resource-recycling laminated film in which a polyethylene-based crystallized film layer having a crystallinity of 80% or more laminated on both surfaces thereof is laminated. .

As described above, according to the present invention, when the polyethylene recycled resin film layer and a polyethylene-based crystallized film layer having a crystallinity of 80% or more laminated on both sides thereof provide an environment-friendly resource-recyclable laminated film, excess polyethylene recycled resin As it has excellent mechanical properties and compatibility as a food packaging material, it can be usefully used for eco-friendly rollbacks, disposable tablecloths, disposable gloves, and the like.

Hereinafter, the present invention will be described in more detail through specific examples or examples, including the accompanying drawings. However, the following specific examples or examples are only one reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the present invention is merely for effectively describing a specific embodiment and is not intended to limit the present invention.

Also, the singular form used in the specification and the appended claims may be intended to include the plural form unless otherwise indicated in the context.

Also, when a part “includes” a certain component, this means that other components may be further included rather than excluding other components, unless otherwise specified.

The present invention can achieve the above object by manufacturing a polyethylene recycled resin film layer and a resource-circulating laminated film in which a polyethylene-based crystallized film layer having a crystallinity of 80% or more laminated on both surfaces thereof is laminated.

In the present invention, in order to impart the high crystallinity, a polyethylene-based film layer having a crystallinity of 80% or more laminated on both sides of the polyethylene recycled resin film layer is obtained by heat-treating a uniaxial or biaxially oriented polyethylene film layer, and mechanical properties and It is better because it can exhibit excellent properties as a food packaging material.

In addition, in the present invention, the thickness of the polyethylene recycled resin film means 50% to 90% of the total thickness of the laminated film, and more preferably, a film to account for a thickness of 55 to 80%. In this case, it is better to be able to faithfully achieve the objectives of physical properties and resource recycling for the purposes of the present invention.

In the present invention, the entire thickness of the laminated film may be used in a thickness of 5 to 50 μm, preferably 10 to 40 μm, which limits the general category used as a rollback, disposable tablecloth, and disposable gloves. Even if the thickness is used outside the range, it is not limited. Preferably, considering good handling properties, mechanical properties, and the like, it preferably has a thickness of 5 to 50 μm. Among them, if considering good packaging characteristics, 10 to 40 μm is suitable, but is not limited thereto.

The polyethylene film layer having a crystallinity of 80% or more, which is laminated on both sides of the polyethylene recycled resin film of the present invention, usually has a crystallinity of a high-density polyethylene resin of about 60% to 80%, the polyethylene-based outer layer film of the present invention It can be seen that the crystallinity of 80% or more, preferably 80% to 98%, has a very large crystallinity, and when a film having a crystallinity of the above category is laminated, a high content of polyethylene recycled resin film layer is used in excess. In spite of this, it is possible to obtain excellent physical properties aimed at by the present invention.

In the present invention, when processing a resin such as 80% or more of a high-crystalline polyethylene-based resin, for example, high-density polyethylene, a high-crystalline resin can be obtained by adjusting a cooling time in order to increase crystallinity.

Therefore, in the present invention, the high crystallinity polyethylene film layer on both sides can control the high crystallinity of 80% or more by adjusting the processing temperature and / or sufficiently providing a cooling rate sufficient to crystallize before or after lamination. When processing a conventional high-density polyethylene resin, considering that the obtained crystallinity is 60 to 80%, the present invention may separately adopt the above means to artificially impart crystallinity of the outer layer film of the final product to 80% or more. .

In addition, it is preferable to add 0.001 to 1 part by weight of the crystal nucleating agent to 100 parts by weight of the resin component to the polyethylene resin in order to promote crystallinity in a short time. The nucleating agent is not particularly limited, and for example, a benzylidene sorbitol derivative, talc, polycyclopentene, etc. are used, and any one or two or more of them can be used in combination. Preferably the talc does not cause migration, so it is best, but not limited to.

In the present invention, the polyethylene recycled resin film is a polyethylene recycled resin produced in a pellet form by collecting and extruding products, such as plastic bags for shopping, used in films, packaging materials, etc. Refers to a film molded from polyethylene recycled resin, which is produced by recovering the molded article of the altered form from the waste.

In the present invention, each layered product of the laminated film needs a pigment, a dye, an antioxidant, a heat stabilizer, a lubricant, an anti-blocking agent, an inorganic filler, and the like in a polyethylene resin, so as not to impair the properties of the object of the present invention. Can be added in For example, in the case of the white pigment, 0.1 to 10 parts by weight may be added to 100 parts by weight of the resin component of each layered product, and other additives may also be used in an amount commonly used in the technical field of the present invention. It can be, the content is not limited as long as it can achieve the object of the present invention.

The crystallinity of the present invention can be obtained by using a differential scanning calorimeter to increase the temperature from a state of 30 ° C at a rate of heating rate of 10 ° C / min and measure it.

In the present invention, the polyethylene constituting the polyethylene recycled resin film layer in the laminated film is not particularly limited and may be any. The polyethylene in the polyethylene recycled resin includes a polyethylene homopolymer or copolymer, and specific examples include high density polyethylene, linear low density polyethylene, low density polyethylene, or mixtures of these polymers, which are better to achieve the object of the present invention, but are not limited thereto. There is no need. For the purpose of maintaining strength and elongation, high density polyethylene is most preferred. Also, considering excellent toughness, transparency, etc., ethylene-propylene-butene random copolymers, ethylene-propylene block copolymers, ethylene-propylene random copolymers or ethylene-propylene-butene block copolymers based on ethylene are preferred. It is not limited to this.

In the present invention, considering the film formability of the polyethylene resin constituting the resource-cycling laminated film, the melt index is suitable in the range of 0.001 g / 10 min to 30 g / 10 min at 190 ° C. When the melt index is less than 0.001 g / 10 minutes, the mechanical load becomes too large during film forming, and when it exceeds 30 g / 10 minutes, it is not preferred because the uniformity of the film thickness after stretching of the polyethylene resin decreases.

In the present invention, in order to increase the degree of crystallinity, when ethylene is axially or biaxially oriented and used, the degree of crystallinity of the oriented polyethylene layer appears very high, but it is also good to slightly adjust the stress by heat treatment, but the crystallinity of the present invention Should be satisfied.

In addition, the thickness ratio of the polyethylene-based resin film layer having a high crystallinity of 80% or more formed on both sides of the polyethylene recycled resin film layer can be arbitrarily selected according to the application. For example, when the polyethylene layer laminated on one side is thicker than the other side, the surface gloss of the thick layer is improved and the strength is increased.

The laminated film of the present invention can be used as a rollback, a disposable tablecloth, and a disposable glove as its main purpose, and as another example, a sealing bag, a packaging bag, and the like.

Considering that the laminated film of the present invention does not break even when an external force is added and has good ductility and does not tear well, tensile strength is 12 MPa or more, tensile elongation is 150% or more, and elution in water 1) lead 1 ( mg / L) or less, 2) potassium permanganate consumption 10 (mg / L) or less, 3) total elution amount 30 (mg / L) or less.

The laminated film of the present invention may be obtained by any method.

Usually, a polyethylene recycled resin film layer is first obtained, followed by laminating and stretching a high crystallinity polyethylene film layer on both sides, followed by quenching, but simultaneously obtained by coextrusion, and can be adopted by adjusting the cooling temperature or stretching ratio. In addition, after preparing a high crystallinity polyethylene film on both sides and then forming a polyethylene recycled resin film in a T-die casting film molding machine, a method of directly heat-bonding the high crystallinity polyethylene film to both sides may be adopted.

The stretching ratio in the stretching is not particularly limited, but preferably, the machine direction (MD) is 2 to 8 times, and the width direction (TD) is preferably 3 to 12 times, but is limited as long as the crystallinity of the present invention is satisfied. I never do that.

In addition, the degree of crystallinity may be increased by heat-treating the laminated film wound in a roll shape. The heat treatment temperature in the heat treatment is not limited as long as the crystallinity does not fall below 80%, and may be appropriately set according to the purpose. Suitably, the heat treatment temperature is selected from 50 ° C to 100 ° C, preferably from 60 ° C to 90 ° C. In addition, the heat treatment time in the heat treatment is not particularly limited, and an optimum time may be determined according to the temperature of the heat treatment. Usually, it is 24 hours to 48 hours.

Next, the white pigment and inorganic filler used in the present invention are not particularly limited, but can be used for each layer as necessary. For example, inorganic materials such as titanium dioxide, silica, and alumina are used, but the present invention is not limited thereto.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following examples and comparative examples are only examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

Measurements in the following examples and comparative examples were carried out as follows.

(1) Crystallinity

Using a differential scanning calorimeter (DSC6200R manufactured by Seiko Electronic Industries, Ltd.), the laminated film specimen was heated from a state of 30 ° C to 235 ° C at a heating rate of 10 ° C / min and measured.

(2) Mechanical properties

A laminated film specimen having a width of 15 mm was measured by a tensile tester (manufactured by Shimadzu, Autograph) under a measurement condition of 100 mm, distance between chucks, and a tensile speed of 300 mm / min, and tensile strength at break (MPa) ) And tensile elongation (%) were obtained, and evaluated as having passed mechanical property standards when the tensile strength was 12 MPa or more and the tensile elongation was 150% or more.

(3) Suitability as food packaging material

Analysis of lead, potassium permanganate consumption and total elution from water for laminated film specimens according to the standards and specifications of the Agency and the packaging and container standards of the Ministry of Food and Drug Safety, lead 1 (mg / L) or less, 2) potassium permanganate consumption 10 (mg / L) or less, 3) When the total elution amount was 30 (mg / L) or less, it was evaluated as having passed suitability as a food packaging material.

[Example 1]

A polyethylene recycled resin (RePE-A) having a melt index of 5.5 g / 10 min was obtained by collecting and extruding waste plastic bags for shopping in a high-density polyethylene material. In addition, a high density polyethylene resin (E308T, Daehan Emulsion, HDPE-A) having a melt index of 1.0 g / 10 min was prepared. A T-die casting film molding machine equipped with an extruder (1) supplied as an intermediate layer and an extruder (2) supplied as an outer layer was prepared. After adding RePE-A to the hopper for the middle layer extruder (1), and HDPE-A to the hopper for the double layer extruder (2), the co-extruded three-layer structured laminated film (medium layer thickness 60%, outside layer thickness 40) %), And then stretched 4 times in the MD direction and 3 times in the TD direction, rapidly cooled, and heat-treated at 170 ° C. for 5 seconds to obtain a laminated film having a thickness of 20 μm. The crystallinity of the outer layer was 93% (this was obtained by analysis of a differential scanning calorimeter for a single-layered HDPE-A film prepared under the same extrusion and stretching conditions by introducing HDPE-A into the intermediate layer). Table 1 shows the results of evaluating the mechanical properties and suitability as a food packaging material for the obtained laminated film.

[Example 2]

A laminate film having a thickness of 20 µm was obtained in the same manner as in Example 1 except that the intermediate layer thickness was 70% and the outer layer thickness was 30%. The crystallinity of the outer layer was 91%. Table 1 shows the results of evaluating the mechanical properties and suitability as a food packaging material for the obtained laminated film.

[Example 3]

A high density polyethylene resin (F120A, Hanwha Total, HDPE-B) having a melt index of 0.044 g / 10 min was prepared. In addition, dibenzoridine sorbitol (CAS No. 32647-67-9, DBS) was prepared as a nucleating agent. An air-cooled upward blown film forming machine equipped with an extruder (1) supplied as an intermediate layer and an extruder (2) supplied as an outer layer was prepared. RePE-A was added to the hopper for the middle layer extruder (1), and a composition composed of 99.8% by weight HDPE-B and 0.2% by weight of DBS was added to the hopper for the extruder layer (2), and then the co-extruded three-layer structure was laminated. After obtaining the film (65% of the middle layer thickness and 35% of the outer layer thickness) in a roll state, the film was left in a room controlled at 80 ° C, heat-treated for 48 hours, and then a final 15㎛ laminated film was obtained. The crystallinity of the outer layer was 89%. Table 1 shows the results of evaluating the mechanical properties and suitability as a food packaging material for the obtained laminated film.

[Comparative Example 1]

In Example 1, a single layer structure RePE-A film having a thickness of 20 µm was obtained in the same manner except that only RePE-A was added to all extruders. The obtained film had a crystallinity of 47%. Table 1 shows the results of evaluating the mechanical properties and suitability as a food packaging material for the obtained laminated film.

[Comparative Example 2]

In Example 1, after stretching only twice in the MD direction and stretching twice in the TD direction, the same method as in Example 1 was performed except that it was naturally cooled in air to obtain a laminated film having a thickness of 20 μm. The crystallinity of the outer layer was 69%. Table 1 shows the results of evaluating the mechanical properties and suitability as a food packaging material for the obtained laminated film.

division Mechanical properties Suitability as food packaging material The tensile strength
(MPa) Tensile elongation
(%) Judgment lead
(mg / L) Potassium permanganate
Consumption (mg / L) Total elution
(mg / L) Judgment Example 1 20 250 fitness 0.1 5 11 fitness Example 2 17 220 fitness 0.2 6 13 fitness Example 3 18 240 fitness 0.2 7 12 fitness Comparative Example 1 5 70 incongruity 2 48 320 incongruity Comparative Example 2 11 130 incongruity 0.5 8 18 fitness

As can be seen in Examples 1 to 3, the laminated film according to the present invention has excellent mechanical properties and suitability as a food packaging material, whereas in the case of a film formed of only the polyethylene recycled resin of Comparative Example 1, the mechanical properties are poor and as a food packaging material It can be seen that there is no suitability, and in the case of the laminated film of Comparative Example 2, the suitability as a food packaging material is good, but the crystallinity of the outer layer polyethylene layer is less than 80%, and the tensile strength and tensile elongation are weak, so rollback, disposable tablecloth, disposable It can be seen that it is not suitable for the mechanical properties required by gloves or the like.

As described above, in the present invention, it has been described by specific matters and limited embodiments and drawings, which are provided to help a more comprehensive understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Various modifications and variations can be made by those skilled in the art from the description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and should not be determined, and all claims that are equivalent or equivalent to the scope of the claims as well as the claims to be described later belong to the scope of the spirit of the invention. .

Claims (7)

A polyethylene recycled resin film layer and a polyethylene-based crystallized film layer having a crystallinity of 80% or more laminated on both sides thereof are laminated,
The polyethylene recycled resin film has a thickness of 50% to 90% of the total thickness of the laminated film. delete According to claim 1,
The resin component of the polyethylene-based crystallized film layer is a high-density polyethylene having a crystallinity of 80 to 98%, a recyclable laminated film. According to claim 1,
The laminated film is a resource-circulating laminated film having a thickness of 5 to 50 μm. According to claim 1,
The resin of the polyethylene-based crystallized film layer is prepared by including a crystal nucleating agent, or after preparing a laminated film, stretching ratio or

Resource-cycling laminated film that is produced by high crystallization to have a crystallinity of 80 to 98% by controlling one or more conditions selected from. According to claim 1,
The laminated film has a tensile strength of 12 MPa or more and a tensile elongation of 150% or more. A resource-cycling laminated film having a total elution of 30 (mg / L) or less. Any one molded article selected from eco-friendly rollback, eco-friendly disposable tablecloth, and eco-friendly disposable gloves obtained from the laminated film of any one of claims 1 and 3 to 6.