KR102128081B1 - biodegradable wrap film of multi layer - Google Patents

Abstract

The present invention relates to an eco-friendly biodegradable multilayer wrap film, and more specifically, to a multilayer wrap film capable of providing an excellent eco-friendly property, excellent elongation, excellent adhesion, and an excellent gas barrier property by implementing a multilayer structure with a coextrusion method by using a biodegradable polymer resin. The eco-friendly biodegradable multilayer wrap film of the present invention comprises: a middle layer which is formed by the biodegradable resin in which a polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT) are mixed; an outer layer which is formed by the biodegradable resin in which the polylactic acid (PLA) and the polybutylene adipate-co-terephthalate (PBAT) are mixed and is thinner than the middle layer; and an inner layer which is formed by a biodegradable resin in which the polylactic acid (PLA), the polybutylene adipate-co-terephthalate (PBAT), and polycaprolactone (PCL) are mixed, and is thinner than the middle layer.

Description

Eco-friendly biodegradable multilayer wrap film{biodegradable wrap film of multi layer}

The present invention relates to an eco-friendly biodegradable multilayer wrap film, and more particularly, to a multi-layer wrap film that is eco-friendly and has excellent elongation, adhesion, and gas barrier properties by implementing a multi-layer structure by coextrusion using a biodegradable polymer resin. .

In recent years, as the interest in hygiene has increased due to the improvement of national living standards, various fruits, vegetables, growth, processed foods, and delivered foods have been stored and distributed in a packaged state.

Synthetic resin films are widely used for their packaging, and among synthetic resin films, wrap films, which are commonly called wraps, have a simple packaging method in addition to the function of preventing foreign substances from entering, and have a freshness retention effect due to moisture blocking effect, etc. It is widely used as.

The wrap film needs to secure elongation (expansibility), adhesion (adhesiveness), and tensile strength among various properties due to the characteristics of the application.

Generally, the wrap film mainly uses synthetic resins such as polyvinylchloride (PVC) resin and low density polyethylene (LDPE) resin.

In order to impart softness, the wrap film of PVC resin is essentially added with a plasticizer, and diethylhexyl adipate (DOA) or diethylhexyl phthalate (DOP) having high elongation and adhesion is mainly used. However, these plasticizers have a problem that they are harmful as endocrine disruptors.

In addition, the wrap film of PE resin does not contain a plasticizer, so it is safe for the human body, but has a low adhesion. There is a problem that can leak out. In the case of applying a separate pressure sensitive adhesive to impart adhesion to the PE resin, the pressure sensitive adhesive is transferred to the surface, thereby deteriorating film winding and unwinding properties.

In addition, PVC resin or PE resin, which is the main material of the conventional wrap film, does not decompose and causes environmental pollution.

1. Republic of Korea Patent Publication No. 10-2009-0069724: Vinyl chloride resin wrap film composition and wrap film prepared therefrom 2. Republic of Korea Patent Publication No. 10-2003-0016441: polyethylene wrap film

The present invention was created to improve the above problems, and has an object to provide an environmentally friendly multi-layer wrap film that can be decomposed in the ground using a biodegradable polymer resin.

In addition, the object of the present invention is to provide a multilayer wrap film having excellent elongation, adhesion, and gas barrier properties by improving the physical properties of the biodegradable polymer resin through the addition of a biodegradable polymer resin, multi-layer structure, and additives.

Eco-friendly biodegradable multi-layer wrap film of the present invention for achieving the above object is a polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) is formed of a biodegradable resin mixed with a middle layer; It is formed on the upper layer of the polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) is formed of a biodegradable resin mixed and the outer layer thinner than the middle layer; It is formed on the lower portion of the middle layer, polylactic acid (PLA), polybutylene adipate terephthalate (PBAT) and polycaprolactone (PCL) is formed of a biodegradable resin mixed and the inner layer thinner than the middle layer; In the middle layer, cellulose nanofiber (CNF) is added in an amount of 2 to 10% by weight to improve gas barrier properties, and in the outer layer, 0.5 to 10% by weight of calcium carbonate is added to improve releasability.

The inner layer is formed of 1 to 10% by weight of the polylactic acid, 40 to 80% by weight of the polybutylene adipate terephthalate, and 10 to 50% by weight of the polycaprolactone.

Ethylene Tetra Fluoro Ethylene, (3,3,3-trifluoropropyl)trimethoxysilane (Trimethoxy(3,3,3-trifluoropropyl)silane) is further added to the outer layer.

As described above, the present invention can provide an environmentally friendly multilayer wrap film because it can be decomposed in the ground using a biodegradable polymer resin.

In addition, the present invention improves the physical properties of the biodegradable polymer resin through the addition of a biodegradable polymer resin, multi-layer structure, and additives to provide a multilayer wrap film excellent in elongation, adhesion, and gas barrier properties.

1 is a cross-sectional view of a multilayer wrap film according to an example of the present invention.

Hereinafter, an eco-friendly biodegradable multilayer wrap film according to a preferred embodiment of the present invention will be described in detail.

Referring to Figure 1, the eco-friendly biodegradable multilayer wrap film 10 of the present invention has a multi-layer (multi layer) structure made of a multi-layer. For example, the present invention consists of three layers. Such a multi-layered structure makes it possible to have appropriate physical properties as a wrap film by different material and physical properties of each layer.

In particular, the present invention can provide a multi-layer wrap film excellent in elongation, adhesion, and gas barrier properties through the addition of an additive, a multi-layered multi-layer structure, a biodegradable polymer resin, despite the use of a biodegradable resin.

The multilayer wrap film 10 of the present invention may be formed to a thickness of 10 to 40 μm so as to have appropriate elongation and strength.

The multi-layer wrap film 10 of the present invention comprises a middle layer 13, an outer layer 15 formed on the upper portion of the middle layer 13, and an inner layer 11 formed on the lower portion of the middle layer 13.

The middle layer 13 occupies the thickest part of the multilayer wrap film 10 of the present invention. The middle layer 13 greatly affects the strength and elongation of the stretch film. The thickness of the middle layer 13 may be 20 to 80% of the thickness of the wrap film 10. When considering strength and elongation, the appropriate thickness of the middle layer 13 may be 10 to 30 μm.

The middle layer 13 is formed of a biodegradable resin. Preferably, polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) may be used as the biodegradable resin. Cellulose nanofiber (CNF) is added to improve gas barrier properties. For example, the middle layer is extruded by mixing 1 to 10% by weight of polylactic acid (PLA), 80 to 95% by weight of polybutylene adipate terephthalate (PBAT), and 2 to 10% by weight of cellulose nanofiber (CNF). .

Polylactic acid (PLA) is a type of biodegradable polymer resin, and has excellent heat resistance and excellent strength among biodegradable polymer resins. The polylactic acid may have a density of 1.2 to 1.3 g/cm ³ and a melt index of 1 to 8 g/10 min (2.16 kg, 190°C).

As a commercialized product of polylactic acid, Nature Works' 2003D and 4032D, which are excellent heat-resistant crystalline PLAs, or Total-Corbion's LX175 can be used.

Polybutylene adipate-co-terephthalate (PBAT) is a biodegradable polymer resin that improves elongation and improves strength. Polybutylene adipate terephthalate may have a density of 1.2 to 1.3 g/cm ³ and a melt index of 1 to 8 g/10 min (2.16 kg, 190°C).

As commercialized products of polybutylene adipate terephthalate, Ecoflex C1200 from BASF, Solpol1000 from Geosol Tech, PBG7070 from EnPol, or A400 from Kingfa can be used.

Cellulose nanofibers (CNFs) refers to nano- or micrometer-sized rod-shaped particles or fibers bound by a bunch of cellulose chains. In addition, cellulose nanofibers have a tensile modulus similar to steel or Kevlar (100-160 GPa), a small density, and a large specific surface area.

Cellulose nanofibers can be produced from bacteria such as Acetobacter xylinum , or obtained through top-down processing in wood pulp or non-wood plants.

Cellulose nanofibers may have a diameter (width) of 5 to 100 nm, and a length of 1 to 100 μm. By adding cellulose nanofibers to the middle layer, the gas barrier property of the wrap film can be greatly improved.

Cellulose nanofiber (CNF) can be used as a product produced by Moorim Paper.

The outer layer 15 is formed on top of the middle layer 13. The outer layer 15 is formed thinner than the middle layer 13. The thickness of the outer layer 15 may be 10-40% of the thickness of the wrap film 10. When considering strength and elongation, an appropriate thickness of the outer layer 3 may be 5 to 20 μm. The outer layer 7 maintains the outer hardness of the wrap film and serves as a cover to prevent deterioration of the properties of the wrap film.

The outer layer 15 is formed of a biodegradable resin. Preferably, polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) may be used as the biodegradable resin. Here, an inorganic filler is added to improve releasability. For example, the outer layer is extruded by mixing 10 to 30% by weight of polylactic acid (PLA), 60 to 85% by weight of polybutylene adipate terephthalate (PBAT), and 0.5 to 10% by weight of an inorganic filler.

The polylactic acid and polybutylene adipate terephthalate used in the outer layer 15 are the same as the polylactic acid and polybutylene adipate terephthalate used in the above-described intermediate layer.

As the inorganic filler, any one selected from calcium carbonate, silica, and talc can be used. Preferably, calcium carbonate is used to improve releasability. Calcium carbonate is added in powder form. The outer layer to which calcium carbonate is added improves releasability, and thus can improve roll release properties.

The inner layer 11 is formed under the middle layer 13. The inner layer 11 is formed thinner than the middle layer 13. The thickness of the inner layer 11 may be 10-40% of the thickness of the wrap film 10. When considering strength and elongation, an appropriate thickness of the inner layer 11 may be 5 to 20 μm. The inner layer 11 is a portion in contact with the object to be packaged and must maintain appropriate strength and adhesion.

The inner layer 11 is formed of a biodegradable resin. As a biodegradable resin, polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and polycaprolactone (PCL) may be used. For example, the inner layer is extruded by mixing 1 to 10% by weight of polylactic acid (PLA), 40 to 80% by weight of polybutylene adipate terephthalate (PBAT), and 10 to 50% by weight of polycaprolactone (PCL). .

The polylactic acid and polybutylene adipate terephthalate used in the inner layer 11 are the same as the polylactic acid and polybutylene adipate terephthalate used in the above-described intermediate layer. The inner layer 11 has a difference in that polycaprolactone is further mixed as a biodegradable resin, unlike the severe and outer layers. Polycaprolactone (PCL) may have a weight average molecular weight of 15,000 to 100,000 g/mol, and a melting point of 50 to 70°C.

As a commercial product of polycaprolactone, SOLVAY's CAPA6200, 6500, 6800, etc. can be used.

By using polylactic acid, polybutylene adipate terephthalate, and polycaprolactone in an appropriate ratio as a biodegradable resin in the inner layer 11, the glass transition temperature (Tg) can be lowered to impart adhesion properties.

The multilayer wrap film 10 of the present invention can be molded into a three-layer structure using a coextrusion method. For example, three layers may be laminated while extruding the molten resin from the three extruders through a T-die to produce a multilayered wrap film.

Since the multi-layer wrap film 10 of the present invention described above uses biodegradable polymer resin, it can be decomposed in the ground and is environmentally friendly. In addition, the present invention can improve the physical properties of the biodegradable polymer resin through the addition of a biodegradable polymer resin, multi-layer structure, and additives to provide a multilayer wrap film excellent in elongation, adhesion, and gas barrier properties.

On the other hand, the present invention may be further added fluorine resin and fluorine silane to the outer layer as another example. For example, the outer layer is 10 to 30% by weight of polylactic acid (PLA), 60 to 85% by weight of polybutylene adipate terephthalate (PBAT), 0.5 to 10% by weight of inorganic filler, 2 to 10% by weight of ethylene tetrafluoroethylene %, (3,3,3-trifluoropropyl)trimethoxysilane 0.1 to 5% by weight can be mixed and extruded.

Ethylene Tetra Fluoro Ethylene is a fluorine-bonded fluorine resin. Since ethylene tetrafluoroethylene does not form a hydrogen bond, it has a relatively low surface energy due to relatively low contact with water droplets. For this reason, the antifouling property can be improved and the non-adhesiveness and releasability of the outer layer can be greatly improved.

(3,3,3-Trifluoropropyl)trimethoxy(3,3,3-trifluoropropyl)silane is a type of fluorine silane, which serves to increase the bonding strength with inorganic filler particles. (3,3,3-Trifluoropropyl)trimethoxysilane is a fluorine compound such as ethylenetetrafluoroethylene, so inorganic filler particles can be added by adding (3,3,3-trifluoropropyl)trimethoxysilane. Strong bond with ethylenetetrafluoroethylene among them. Accordingly, the physical properties of the outer layer can be improved.

Hereinafter, the present invention will be described through the following examples. However, the following examples are intended to illustrate the present invention in detail, and the scope of the present invention is not limited to the following examples.

(Example)

As a biodegradable resin, using polylactic acid (2003D, Nature Works), polybutylene adipate terephthalate (Ecoflex C1200, BASF), polycaprolactone (CAPA6200, SOLVAY) total thickness 20㎛ as shown in Table 1 below A three layer wrap film was prepared. The three-layer structured wrap film was prepared using a 3-layer T-die cast extrustionn method.

division Furtherance thickness Outer layer PLA 20wt%, PBAT 75wt%, Calcium carbonate 5wt% 6㎛ Middle class PLA 8wt%, PBAT 86wt%, CNF 6wt% 8㎛ Inner layer PLA 5wt%, PBAT 65wt%, PCL 30wt% 6㎛

(Comparative example)

The wrap films of Comparative Examples for comparison with Examples are shown in Table 2 below. Comparative Example 1 was extruded into a single layer structure with the same composition as the inner layer of Example, and Comparative Example 2 was extruded into a single layer structure with the same composition as the middle layer of Example. And Comparative Example 3 was extruded into a single layer structure using one type of polyvinyl chloride (PVC) resin, and Comparative Example 4 was extruded into a single layer structure using one type of polyethylene (PE) resin.

division Furtherance thickness Comparative Example 1 PLA 5wt%, PBAT 65wt%, PCL 30wt% 20㎛ Comparative Example 2 PLA 8wt%, PBAT 86wt%, CNF 6wt% 20㎛ Comparative Example 3 PVC wrap film 20㎛ Comparative Example 4 PE wrap film 20㎛

<Physical property test>

(1) Experiment method

The physical properties were tested in the following manner for the wrap films of Examples and Comparative Examples.

-Adhesive force: Measured using UTM equipment (Test One Co., Ltd.) according to the KS A1107 standard.

-Tensile strength and elongation: Measured using UTM equipment (Test One, Inc.) according to ASTM D882 standard.

-OTR Barrier property: Oxygen permeability at 0% relative humidity (cc/m ² ·day·atm) using air permeability meter (OX-TRAM 2/21, MOCON, USA) according to the standard measurement method of ASTM D3985 Was measured and further evaluated over time after 90 days.

-Transfer transfer: After cutting the specimen to 70mm×20mm, use a slide glass (trade name MARIENFELD, Micro Slide Glass, Plain, 76×26 standard) to adhere once at 3kgf pressure at room temperature, and then at 60℃ for 72hr in an 80% thermo-hygrostat. After standing, the presence or absence of metastatic transcription was observed using a three-wavelength lamp in the dark.

-Roll looseness: After winding the wrap film in a roll state, it is evaluated as good when it is released without noise by checking whether there is noise or not when released by hand. It was evaluated.

-Biodegradability: Commissioned by KTR (Korea Research Institute of Chemical Technology), the film biodegradability was measured under composting conditions.

(2) Experimental results

Table 3 below shows the experimental results.

division Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 adhesiveness
(gf/25mm) 145 142 87 140 30 Elongation (%) 210/520 200/500 200/500 200/500 120/500 The tensile strength
(gf/mm ² ) 250~260 250~255 250~255 250 200 OTR Barrier
(cc/m ² ·day·atm) 10~15 More than 1000 10~15 100~200 More than 1000 OTR Barrier 90 days later
(cc/m ² ·day·atm) 10~15 More than 1000 100~200 100~200 More than 1000 Transfer warrior none none none Occurs none Roll release Good usually usually usually usually Biodegradability Biodegradation over 90% within 6 months Biodegradation over 90% within 6 months Biodegradation over 90% within 6 months Not biodegradable
Not Not biodegradable
Not

Referring to the results of Table 3, the wrap film of the Example was confirmed to have a higher adhesive strength compared to the PVC wrap film (Comparative Example 3) known to have excellent adhesive strength. Therefore, the wrap film of the present invention was found to improve the adhesion of the inner layer through the combination of polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and polycaprolactone (PCL).

In addition, the elongation and tensile strength were equal to or better than those of the PVC wrap film (Comparative Example 3) or PE wrap film (Comparative Example 4).

And the gas barrier properties also showed that the wrap film of the example was the best. Initially, both the example and the comparative example 2 had excellent gas barrier properties, but after 90 days, the comparative example 2 showed that the gas barrier property rapidly decreased. On the other hand, the examples showed that the gas barrier properties were maintained even after 90 days.

And except for Comparative Example 3, it was confirmed that there was no transfer transcript, and it was found that only the example was good in the roll release property. This seems to be due to the result that the outer layer was formed with a composition different from the middle layer and the inner layer in the case of the Examples.

In addition, Examples and Comparative Examples 1 and 2 made of a biodegradable resin showed excellent decomposition of 90% or more within 6 months, and thus had excellent biodegradability. On the other hand, Comparative Examples 3 and 4 were found not to decompose.

As described above, the present invention has been described with reference to one embodiment, but this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent embodiments are possible therefrom. Therefore, the true protection scope of the present invention should be defined only by the appended claims.

10: wrap film 11: inner layer
13: middle layer 15: outer layer

Claims (3)

delete delete Biodegradability of 1 to 10% by weight of polylactic acid (PLA), 80 to 95% by weight of polybutylene adipate terephthalate (PBAT), and 2 to 10% by weight of cellulose nanofibers (CNF) to improve gas barrier properties A middle layer formed of a resin and having a thickness of 10 to 30 µm;
Formed on top of the middle layer, 10 to 30% by weight of polylactic acid (PLA) and 60 to 85% by weight of polybutylene adipate terephthalate (PBAT), 0.5 to 10% by weight of calcium carbonate as an inorganic filler to improve releasability Is formed of a mixed biodegradable resin and the outer layer having a thickness of 5 to 20㎛ thinner than the middle layer;
It is formed on the lower portion of the middle layer, polylactic acid (PLA) 1 to 10% by weight of polybutylene adipate terephthalate (PBAT) 40 to 80% by weight, polycaprolactone (PCL) 10 to 50% by weight of biodegradation mixed It is formed of a resin and thinner than the middle layer, the inner layer having a thickness of 5 to 20㎛;
The cellulose nanofibers are rods formed by bundles of cellulose chains, having a diameter or width of 5 to 100 nm and a length of 1 to 100 μm,
The outer layer is ethylene tetrafluoroethylene (Ethylene Tetra Fluoro Ethylene) 2 to 10% by weight, (3,3,3-trifluoropropyl) trimethoxysilane (Trimethoxy(3,3,3-trifluoropropyl)silane) 0.1 Eco-friendly biodegradable multi-layer wrap film, characterized in that 5% by weight is further added.

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