KR101970636B1 - High tensile modulus and heat resistant resin composition and multilayer film for vacuum skin packaging comprising the same - Google Patents

Abstract

The present invention relates to a high-elasticity and heat-resistant resin composition and a multilayer film for packaging a vacuum skin comprising the same. More specifically, the present invention relates to a resin composition that can be applied as a skin layer of a multilayer film for packaging a vacuum skin and a multilayer film comprising the same, by exhibiting heat resistance and high tensile elastic modulus that do not stick to a hot plate under high temperature conditions.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-elasticity and heat-resistant resin composition, and a multilayer film for packaging a vacuum skin comprising the same. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a high-elasticity and heat-resistant resin composition and a multilayer film for packaging a vacuum skin comprising the same. More specifically, the present invention relates to a resin composition that can be applied as a skin layer of a multilayer film for packaging a vacuum skin and a multilayer film comprising the same, by exhibiting heat resistance and high tensile elastic modulus that do not stick to a hot plate under high temperature conditions.

Vacuum skin packaging is a packaging method in which heat is applied to a film at high temperature and then it is brought into close contact with the contents by using air pressure or vacuum. It is effective in improving the appearance of the appearance of the package and preservation Therefore, it is widely used in fresh meat, processed meat, seafood, or simple cooking food. On the other hand, since the vacuum skin packaging is basically a hot plate or a dome-shaped heat plate on the upper side, the film is heated and molded, so that the vacuum skin packing film should not adhere to the resin layer of the outer layer on the hot plate or the sealing portion In addition, properties such as heat resistance and modulus of elasticity of the surface resin layer are required so that heat deformation such as melting, stretching, or shrinkage occurs at a high temperature.

An oxygen-barrier vacuum skin packaging film using an ionomer as an outermost layer as a resin having a high modulus of elasticity is known. An example of such a multilayer structure film is an ionomer / EVOH (ethylene vinyl alcohol copolymer) / sealant layer resin. At this time, the ionomer is an ethylene- (meth) acrylate and has a high elastic modulus, so that the film does not melt when heated at a high temperature and has excellent moldability and is widely used. However, the ionomer has insufficient heat resistance, which causes defects such as sticking to a hot plate or sticking to a sealing part in an automatic packaging line requiring a higher temperature. In addition, since the ionomer resin has a high heat shrinkage and shrinks around the heat plate when the molding depth is deep, when the vacuum skin packaging is carried out at a high temperature, the appearance of the package due to heat wrinkling is caused. In order to solve this problem, it is possible to reduce the heat shrinkage rate through crosslinking, but in order to sufficiently lower the heat shrinkage ratio, a considerable amount of crosslinking energy is required, resulting in a decrease in productivity and a large-scale facility. Also, even in the case of crosslinking, if the time of contact with the hot plate or the sealing time is prolonged, a phenomenon of sticking or elongation may occur and holes or breakage may occur, resulting in poor Lt; / RTI >

As a method for improving the heat resistance of the ionomer resin, there has been proposed a method of crosslinking an ionomer by blending a heat resistant resin such as polyamide or polyester or adding an additive such as peroxide. However, the methods of blending the heat resistant resin are reduced in transparency and the method of crosslinking by peroxide induces gel, so that it is difficult to apply the method to the production of a vacuum skin packaging film in which the appearance after packaging is important.

In order to solve the above problems, it is an object of the present invention to provide a resin composition which contains an ionomer and is excellent in heat resistance and tensile modulus, and which has little heat shrinkage.

Further, by using a film comprising at least one layer of the resin composition as a skin layer of a multilayer film for packaging a vacuum skin, it is desired to provide a film having excellent moldability without adhering to a hot plate and suffering heat wrinkling.

In order to achieve the above object, the present invention relates to a high heat resistance and high modulus resin composition and a multilayer film comprising the same.

Specifically, one aspect of the present invention is

(a) a first ionomer resin composed of ethylene- (meth) acrylate, and

(b) a modified polymer by reaction of a second ionomer resin made of an ethylene- (meth) acrylate with a polyamide oligomer,

Elasticity and heat resistance.

In one embodiment of the high-elasticity and heat-resistant resin composition of the present invention, 1 to 20 parts by weight of an ethylene-vinyl acetate copolymer may be added to 100 parts by weight of the resin composition.

In one embodiment of the high-elasticity and heat-resistant resin composition of the present invention, the ethylene-vinyl acetate copolymer may have a vinyl acetate content of 10% by weight or less.

In one embodiment of the high-elasticity and heat-resistant resin composition of the present invention, the high-elasticity resin composition may comprise 70 to 99% by weight of the first ionomer resin and 1 to 30% by weight of the modified polymer.

In one embodiment of the high-elasticity and heat-resistant resin composition of the present invention, the modified polymer may have a content of the second ionomer resin: polyamide oligomer in a weight ratio of 10:90 to 90:10.

In one embodiment of the high-elasticity and heat-resistant resin composition of the present invention, the first ionomer resin and the second ionomer resin have a part of the carboxyl groups of the ethylene- (meth) acrylic acid copolymer having an ethylene content of 10 to 95 mol% And may be one which satisfies the following expression (1).

[Formula 1]

MFR ₁ < MFR ₂

In the above formula 1, MFR ₁ is the melt flow rate of the first ionomer resin and MFR ₂ is the melt flow rate of the second ionomer resin.

In one embodiment of the high-elasticity and heat-resistant resin composition of the present invention, the polyamide oligomer may have a weight average molecular weight of 500 to 5,000 g / mol.

Another embodiment of the present invention is a single layer made of the above-mentioned high-elasticity and heat-resistant resin composition or a laminate of two or more layers.

Another embodiment of the present invention is a multilayer film for packaging a vacuum skin, which comprises the film as a skin layer and includes a gas barrier layer.

The multilayered film of the present invention may be crosslinked by electron beam irradiation.

The resin composition of the present invention and the film containing the same have the advantage that they can be used as a film for wrapping a vacuum skin since they do not stick to a hot contact portion when heated at a high temperature and are excellent in thermal property formation and heat shrinkage is remarkably reduced.

When the film using the composition according to the present invention is contained in the skin layer, heat shrinkage is not easily generated at the time of packing the vacuum skin due to low heat shrinkage at high temperature and high heat resistance, and no break at high temperature occurs. Automatic packaging machine, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described more fully hereinafter with reference to the accompanying drawings, It should be understood, however, that the invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the invention.

Unless otherwise defined, 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 invention is merely intended to effectively describe a specific embodiment and is not intended to limit the invention.

Also, the singular forms as used in the specification and the appended claims are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The term &quot; high elasticity &quot; in the present invention means that the film produced by using the high-elasticity and heat-resistant resin composition of the present invention is irradiated with electron beams and cross-linked, and then the measured tensile modulus is measured with respect to the machine direction (MD) and the transverse direction 80 kg / cm 2 or more, more specifically 80 to 100 kg / cm 2. In this case, the dose of the electron beam may be 50 to 200 kGy, preferably 70 to 150 kGy.

The term &quot; heat resistance &quot; in the present invention means that when a film produced by using the high elasticity and heat resistant resin composition of the present invention is irradiated with an electron beam and crosslinked, the film is maintained at 200 DEG C for 30 seconds to have a heat shrinkage of 15% Specifically, it means 0.1 to 15%. In this case, the dose of the electron beam may be 50 to 200 kGy, preferably 70 to 150 kGy.

In the present invention, the term 'modified polymer' refers to a resin obtained by melt-extruding an ionomer resin and a polyamide oligomer and grafting the polyamide oligomer onto the ionomer. The melt extrusion method may be carried out by melt extrusion using a Brabender mixer, a single screw extruder or a twin screw extruder, for example, It is not.

The inventors of the present invention have studied to develop an ionomer composition having excellent elasticity and heat resistance. As a result, it has been found that two kinds of ionomers are used, and a modified polymer is prepared by reacting any one of the ionomers with a polyamide oligomer It is possible to improve the high elasticity, heat resistance and heat shrinkage of the present invention, thereby completing the present invention.

Further, it has been found that the reforming polymer can be produced by reacting an ionomer having a high melt flow rate with the polyamide oligomer among the two types of the above-mentioned ionomers, thereby further improving moldability and heat resistance and further improving heat shrinkage Respectively.

Further, the present inventors have found an amazing effect that the heat resistance and the tensile elastic modulus are further improved by further including an ethylene-vinyl acetate copolymer in the resin composition, thereby completing the present invention.

Therefore, one embodiment of the high-elasticity and heat-resistant resin composition of the present invention is not limited, but specific examples thereof are as follows.

The first aspect of the present invention relates to a method for producing a polyimide oligomer comprising the steps of (a) reacting a first ionomer resin comprising an ethylene- (meth) acrylate salt and (b) a second ionomer resin comprising an ethylene- (meth) &Lt; / RTI &gt;

In a second aspect of the present invention, in the first aspect, the first ionomer resin and the second ionomer resin satisfy the following formula (1).

[Formula 1]

MFR ₁ < MFR ₂

In the above formula 1, MFR ₁ is the melt flow rate of the first ionomer resin and MFR ₂ is the melt flow rate of the second ionomer resin.

In a third aspect of the present invention, in the first or second aspect, an ethylene-vinyl acetate copolymer is further included.

Hereinafter, each configuration of the present invention will be described in more detail.

In one embodiment of the present invention, the first ionomer resin and the second ionomer resin may be one in which some of the carboxyl groups of the ethylene- (meth) acrylic acid copolymer having an ethylene content of 10 to 95 mol% are neutralized with a salt. More specifically, some of the carboxyl groups may be neutralized with an alkali metal cation or an ammonium ion, specifically, for example, Na ^+, Li ^+, Ka ^+, Zn ^{2 +,} Co ^{2 +,} Ni ^{2 +,} Mn ^{2 +} , Pb ^{2 +} , Cu ^{2 +} and Mg ^{2 +,} and the like, but the present invention is not limited thereto. The degree of neutralization of the carboxyl group may be from 30 to 99.9 mol%. In particular, the degree of neutralization of the carboxyl group of the second ionomer resin may be in the range of 30 to 99.9 mol%, and the modified polymer may be obtained by polymerization with a polyamide oligomer But is not limited thereto.

Specific examples of the ethylene- (meth) acrylic acid copolymer may include an ethylene acrylic acid copolymer and an ethylene methacrylic acid copolymer, and if necessary, an ethylene-itaconic acid copolymer, an ethylene maleic anhydride copolymer, an ethylene maleic anhydride copolymer Copolymers and ethylene-maleic anhydride monoethyl-co-polymers.

The first ionomer and the second ionomer may be the same or different resins, and more preferably the range satisfying the formula (1). More specifically, for example, the difference between the melt flow rates of the first ionomer and the second ionomer may be at least 1 g / 10 min. Wherein the melt flow rate is measured by ASTM D1238, measured at 190 占 폚 and 2.16 kg.

More specifically, the first ionomer may have a melt flow rate (MFR) of 0.1 to 3.0 g / 10 min (190 ° C, 2.16 kg), and the second ionomer may have a melt flow rate of 3.0 to 20.0 g / Min (190 DEG C, 2.16 kg), and the difference between the melt flow rates of the first ionomer and the second ionomer may be at least 1 g / 10 min. But is not limited thereto, it is preferable because it is possible to provide a resin composition having excellent heat resistance and high elasticity within the above range.

Commercial examples of the ionomer include, but are not limited to, the Surlyn series manufactured by DuPont.

In one aspect of the present invention, the modified polymer refers to a polymer obtained by reacting an unneutralized carboxylic acid group of a second ionomer with an amine group, which is a terminal group of a polyamide, while the second ionomer and the polyamide oligomer are melt- , And by using it, it can serve as a modifier that can improve the heat resistance. The melt extrusion method may be carried out by melt extrusion using a Brabender mixer, a single screw extruder or a twin screw extruder, for example, It is not.

In one embodiment of the present invention, the modified polymer may have a content of the second ionomer resin: polyamide oligomer in a weight ratio of 10:90 to 90:10, preferably 60:40 to 90:10 by weight, 70: 30 to 80:20 by weight. But it is not limited thereto since it satisfies the objective heat resistance and tensile elastic modulus within the above range.

In one embodiment of the present invention, the polyamide oligomer may be prepared by adding a molecular weight modifier in the course of preparing the polyamide, but is not limited thereto. The molecular weight regulator may be any one selected from aliphatic alcohols, aliphatic amines, aromatic alcohols, aromatic amines, and polyether oligomer compounds, or a mixture of two or more thereof.

Preferably, it may be prepared by reacting a primary amine with a lactam and a molecular weight modifier.

The lactam may be a lactam having 4 to 12 carbon atoms. Specific examples thereof include 2-pyrrolidone, caprolactam, oenantheractam, capryllactam, ferulolactam, caprinolactam, 11-undecanolactam And lauryl lactam, and the like, or a mixture of two or more thereof.

 The primary amine is selected from the group consisting of n-heptylamine, n-octylamine, n-dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, nonylamine, benzylamine, And cyclohexylamine, or a mixture of two or more thereof.

In one embodiment of the present invention, the process for preparing a polyamide oligomer comprises reacting the lactam, the primary amine and water in a pressurized reactor, sealing and then reacting at 200 to 300 ° C, more specifically 220 to 270 ° C have. Thereafter, the polyamide oligomer can be prepared by opening the pressure regulating valve and adjusting the pressure to 200 to 300 ° C, more specifically 220 to 270 ° C.

More specifically, examples of the polyamide oligomer include polyamide-6, polyamide-6,6, polyamide-4,6, polyamide-11, polyamide-12, polyamide- 6, 12, polyamide 6/6, polyamide 6/6, 12, polyamide MXD 6, polyamide 6, T, polyamide 6, I, polyamide 6/6, T I, polyamide-6,6 / 6, T, polyamide-6,6 / 6, I, polyamide-6/6, T / 6, I, polyamide- Polyamide-6/12/6, T, polyamide-6/12/6, I, polyamide- 6/12/6, I, and copolymers thereof.

In one embodiment of the present invention, the polyamide oligomer may have a weight average molecular weight of 500 to 5,000 g / mol. More preferably a weight average molecular weight of 1,000 to 4,000 g / mol, but is not limited thereto. When the weight average molecular weight of the polyamide oligomer is within the above range, the probability of reaction with the ionomer increases due to excellent flowability during melt extrusion, and the excellent effect of the present invention can be exhibited. Also, the mechanical and thermal properties according to the composition of the present invention are preferably improved.

The polyamide oligomer may have an average degree of polymerization of 5 to 35, and the resin composition having an excellent tensile modulus in the above range can be provided, however, the present invention is not limited thereto.

In one embodiment of the present invention, the high-elasticity and heat-resistant resin composition may contain 70 to 99% by weight of the first ionomer resin and 1 to 30% by weight of the modified polymer. And more preferably 80 to 90% by weight of the first ionomer resin and 10 to 20% by weight of the modified polymer. In this range, the tensile modulus and the heat shrinkage can be further reduced. When the modified polymer is used in an amount exceeding 30% by weight, transparency may be lowered and mechanical strength may be lowered when the film is used. .

The high heat resisting high modulus resin composition of the present invention may be mixed with an extruder after being subjected to dry blending or melt blending according to the production conditions of the product to be formed into a molded product. Dry mixing may be performed using equipment such as a tumbler mixer, and melt mixing may be performed using equipment such as a blender mixer, single shaft or twin screw extruder.

In one embodiment of the present invention, the high-elasticity and heat-resistant resin composition may further comprise an ethylene-vinyl acetate copolymer with respect to 100 parts by weight of the resin composition in order to further improve the heat resistance and the tensile elastic modulus. The content thereof is not limited, but it may be from 1 to 20 parts by weight, more specifically from 3 to 15 parts by weight. The heat resistance is further improved in the above range and the transparency can be further improved.

The ethylene-vinyl acetate copolymer (EVA) is a polymer produced by the copolymerization reaction of ethylene and vinyl acetate (VA), and the total weight of the ethylene-vinyl acetate copolymer The content of vinyl acetate may be 10% by weight or less, more preferably 3 to 10% by weight, and is preferably, but not exclusively, excellent in heat resistance, heat shrinkability and transparency within the above range.

If necessary, additives such as an anti-blocking agent, a slip agent, a processing aid, a dye, an antioxidant, a light stabilizer, a plasticizer, a releasing agent, and a wear resistance improver may be used in the high-elasticity and heat-resistant resin composition of the present invention. The content can be applied within a range that does not affect the properties of heat resistance and high elasticity.

Another aspect of the present invention may be to produce a film having one layer or two or more layers laminated using the above-mentioned high-elasticity and heat-resistant resin composition. When the two or more layers are laminated, they may be produced by co-extrusion, and may be made of the same or different high-elasticity and heat-resistant resin composition. But the extrusion temperature may be 150 to 250 ° C.

Further, it may be a multilayer film containing the film as a skin layer. The film having the skin layer exhibits a heat resistance and a high modulus of elasticity that do not adhere to the hot plate under high temperature conditions, so that it can be applied as an outermost layer of a multilayer film for packaging a vacuum skin.

The skin layer can be produced by processing the gas barrier resin composition of the present invention using a processing apparatus such as blown casting or cast extrusion molding, but is not limited thereto.

For example, the film according to an embodiment of the present invention may be laminated in various configurations with the high elastic and heat resistant resin composition A, the adhesive resin B, the gas barrier resin C, and the thermoplastic resin D, respectively. A / D, A / B, A / D, A / B / C / B / D, A / / B / C / B / A / D, or the like, but the present invention is not limited thereto. Other functional layers such as a sealant layer may be further included, but the present invention is not limited thereto. Since the multilayer film according to the above-described embodiment includes the film using the above-mentioned high-elasticity and heat-resistant resin composition as the skin layer, it can exhibit the effect of preventing the sticking to the hot plate at the time of high- It is not.

As the adhesive resin, for example, a resin obtained by grafting a polyolefin resin such as polyethylene or polypropylene with an unsaturated acid such as maleic acid can be used. As a concrete example, the adhesive resin is for enhancing the adhesive force at the interface between the layers of the multilayer film, and can be applied to prevent phase separation between the layers.

(MAH-g-LDPE), maleic anhydride-grafted linear low density polyethylene (MAH-g-LLDPE), maleic anhydride grafted high density polyethylene (MAH-g-LDPE), and maleic anhydride- g-HDPE), maleic anhydride-grafted ethylene vinyl acetate (MAH-g-EVA), and the like, but the present invention is not limited thereto.

The gas barrier resin is not particularly limited as far as it is used in the related art, but it plays a role to block oxygen and moisture. Specific examples thereof include an ethylene vinyl alcohol copolymer and the like. It is not.

As the thermoplastic resin, polyethylene, polypropylene, polystyrene, polyamide or the like may be used for imparting the flexibility and basic mechanical strength of the multilayered film, but the present invention is not limited thereto.

The sealant layer is not limited as long as it is commonly used in the field, and specifically, for example, an ethylene-vinyl acetate copolymer may be used, but is not limited thereto.

One aspect of the multilayer film for packaging a vacuum skin of the present invention may comprise a sealant layer, an adhesive layer, a gas barrier layer, an adhesive layer, and a skin layer. For example, the total thickness may be 500 탆 or less, more specifically, 10 to 500 탆.

The multilayered film for packaging a vacuum skin of the present invention may be crosslinked by irradiating an electron beam, and the dose of the electron beam may be 50 to 200 kGy, preferably 70 to 150 kGy. By irradiating and crosslinking the electron beam in the above range, heat resistance can be further improved, heat shrinkage can be further improved, and breakage or the like does not occur during molding.

The multilayer film according to an embodiment of the present invention may be laminated by coextrusion, but is not limited thereto.

In the present invention, co-extrusion can be carried out in a coater such as a tie die, a blower and a tubular type extruder according to a desired product thickness at the time of co-extrusion, and a uniaxial extruder or a twin screw extruder can be freely selected depending on the form and use of the product . When the melting temperature is lower than the temperature range during extrusion, the interlaminar adhesive strength is lowered. If the temperature is higher than the above range, excessive thermal decomposition occurs, and bubbles due to pyrolysis products may be formed on the sheet.

The temperature condition at the time of extrusion according to the present invention may vary depending on the type and content of the composition, and is not particularly limited. For example, the temperature of the thermoplastic resin is 160 to 230 DEG C, the adhesive layer containing the adhesive resin is 160 to 230 DEG C, The sealant layer may be 160 to 230 占 폚, and the gas barrier layer may be 160 to 230 占 폚, 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 merely examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

The following physical properties were measured as follows.

1) Melt flow rate (MFR)

Measured according to ASTM D1238 at 190 占 폚, 2.16 kg. The unit is g / 10min.

2) Density

ASTM D792. The unit is g / cm3.

3) Tensile modulus

Using a UTM instrument from Instron, the measurement was carried out at a speed of 500 mm / min in a 15 mm width according to the method of ASTM D882. The unit is kgf / cm2.

4) Heat shrinkage

The film was placed in oil at 200 캜, heated for 30 seconds, taken out, and the dimensional change was measured. The smaller the value, the less heat shrinkage occurs, and the heat resistance is excellent.

5) Weight average molecular weight

GPC Column: TSKgel SuperMultipore Hz-N (Tosoh Corporation)

Column temperature: 40 ° C

Solvent: Tetrahydrofuran

Flow rate: 1 ml / min

Standard samples: Polystyrene (Tosoh Corporation)

6) Heat plate release

Sealing was performed for 2 seconds at a pressure of 2 atm with a 50 mm dome type surface plate at a temperature of 175 캜. The film was then detached from the soleplate, and whether or not the film surface adhered to the ceiling or sealing area of the soleplate was checked.

7) Number of breaks

During the vacuum skin packaging process, the film is stretched at the corners or sharp portions of the tray to form a thin region at a heating plate temperature of 175 ° C, a vacuum pressure of 100 mbar, and a vacuum skin time (film swelling time by vacuum) for 7 seconds. And it was confirmed whether a hole was formed and a break occurred. When the film breaks, a vacuum is not applied between the contents and the tray.

The total number of times of breakage is indicated by repeating 10 times in total.

8) Haze

It was measured by ASTM D1003 method using a NIPPON DENSHOKU 300A haze meter analyzer in Japan.

Haze (%) = (diffusion transmittance (Td) / total light transmittance (Tt)) x 100

[Preparation Example 1] Preparation of polyamide oligomer (PAO)

17 kg of caprolactam, 1.09 kg of dodecylamine, and 390 g of water were sealed in a 50 L capacity pressurized reactor and reacted with stirring at 260 DEG C for 2 hours. At this time, the pressure of the pressurized reactor rose to 5 kg / cm &lt; 2 &gt;.

The pressure regulating valve was opened and the pressure was adjusted to normal pressure. Then, the reaction was continued at 260 ° C for 2 hours and the temperature was dropped to room temperature to obtain a solid component. These solid components were pulverized in a pulverizer to prepare a powder, stirred in boiling water for 2 hours, filtered and dried in a vacuum oven at 80 DEG C for 8 hours. The melting temperature of the obtained polyamide oligomer was 210 ° C. The terminal amine group was measured by an acid base titration method and found to have a degree of polymerization of 25 and a weight average molecular weight of 3,040 g / mol.

[Preparation Example 2] Preparation of modified polymer

(B-1 to B-5), which are reactants of the ionomer and the polyamide oligomer (PAO) prepared in Production Example 1, were prepared as shown in Table 1 below.

(Dry Blending) at the weight ratios shown in the following Table 1, and then the mixture was extruded at 180 ° C, 200 ° C, 220 ° C, 240 ° C, 250 ° C, and 250 ° C using a twin screw extruder having a diameter of 19 mm And the mixture was melt-extruded at a temperature of 260 占 폚 in six zones to prepare a pallet.

 (b) Component Resin type
(weight%) B-1 Surlyn 1702 ¹⁾ : PAO = 80: 20 B-2 Surlyn 1652 ²⁾ : PAO = 80: 20

1) DuPont Surlyn 1702: zinc ionomer, MFR 14 g / 10 min, density 0.95 g / cm3

2) DuPont Surlyn 1652: zinc ionomer, MFR 5.2 g / 10 min, density 0.94 g / cm &lt; 3 &

[Example 1]

80% by weight of Surlyn 1707 (sodium ionomer, MFR 0.9 g / 10 min, density 0.95 g / cm 3, hereinafter referred to as 'A-1' in Table 2) of DuPont Co., %, And then melt-extruded at 190 DEG C in a single-layer blowing machine to prepare a film having a thickness of 50 mu m.

The film was crosslinked by irradiating electron beams at an intensity of 120 kGy, and the shrinkage ratio before and after crosslinking was measured. The results are shown in Table 2.

[Example 2]

As shown in the following Table 2, a film having a thickness of 50 탆 was prepared in the same manner as in Example 1, except that B-2 prepared in Preparation Example 2 was used.

The physical properties of the prepared film were measured and are shown in Table 2 below.

[Example 3]

As shown in the following Table 2, with respect to 100 parts by weight of the composition of Example 1, an ethylene-vinyl acetate copolymer having a melt index of 0.5 g / 10 min measured at 190 ° C under a load of 2.16 kg, manufactured by Hanwha Chemical Co., A vinyl acetate content of 3.5% by weight, hereinafter referred to as &quot; C-1 &quot; in Table 2) was used as a crosslinking agent.

The physical properties of the prepared film were measured and are shown in Table 2 below.

[Comparative Example 1]

As shown in Table 2, except for using Surlyn 1707 (sodium ionomer, MFR 0.9 g / 10 min, density 0.95 g / cm 3, hereinafter referred to as 'A-1' in Table 2) 1, a film having a thickness of 50 탆 was prepared.

The physical properties of the prepared film were measured and are shown in Table 2 below.

Component A: Component B
(weight%) Component C
(Parts by weight) Tensile modulus after crosslinking
(kg / cm2) MD direction heat shrinkage before crosslinking
(%) Heat shrinkage in MD direction after crosslinking
(%) Hayes
(%) MD TD Hayes
(%) Example 1 A-1: B-1 = 80: 20 - 92 96 62 10 8 Example 2 A-1: B-2 = 80: 20 - 92 95 60 9 7 Example 3 A-1: B-1 = 80: 20 C-1
5 96 97 61 7 5 Comparative Example 1 A-1 = 100 - 93 91 74 20 6

As shown in Table 2, it was found that, by mixing a modified polymer with an ionomer resin having a high modulus, it is possible to produce a film having a remarkably low heat shrinkage while maintaining the modulus of elasticity.

Further, as shown in Example 3, it was confirmed that when the ethylene-vinyl acetate copolymer was further added, the modulus of elasticity, heat shrinkage and transparency were further improved.

[Example 4]

A multi-layer film was prepared using a pneumatic actuator having five melt extruders of 60/50/50/50/60 mm. At this time, the multilayer film was formed by laminating the sealant layer, the adhesive layer, the gas barrier layer, the adhesive layer, and the skin layer in a total thickness of 100 μm in a thickness of 37/7/7/7/42 μm.

An ethylene-vinyl acetate copolymer (melt index: 0.7 g / 10 min, density: 0.939 g / cm 3, vinyl acetate content: 18 wt%, Hanwha, EVA X 1218, measured at 190 ° C under a load of 2.16 kg) was used as the sealant layer in an extruder Lt; RTI ID = 0.0 &gt; 190 C. &lt; / RTI &gt;

Linear density polyethylene (having a melt index of 1.2 g / 10 min and a density of 0.919 g / cm 3, measured at 190 ° C under a load of 2.16 kg, in which maleic anhydride was grafted onto the adhesive layer adjacent to both sides of the gas barrier layer) To 190 &lt; 0 &gt; C.

An ethylene vinyl alcohol copolymer (ethylene content: 44 mol%, T _m : 167 캜, E171B, Kuraray co.) Was used as the gas barrier layer at an extruder temperature of 220 캜.

As the composition of the present invention, 80% by weight of A-1 and 20% by weight of B-1 were dry mixed as the skin layer, and the mixture was put into an extruder to prepare an extruder at a temperature of 220 ° C.

The resulting multilayer film was passed through an electron beam irradiator at 95 kGy intensity, and heat shrinkage was measured. The packaging test was performed in a vacuum skin packing machine (Italian Pack, Olympus model). The results are shown in Table 3 below.

[Examples 5 to 11 and Comparative Examples 2 to 3]

Except that the composition of the skin layer and the crosslinking conditions were different as shown in Table 3 below. The crosslinking condition I was 95 kGy, and the crosslinking condition II was 130 kGy.

In Examples 10 and 11, 100 parts by weight of a highly elastic and heat-resistant resin composition of the skin layer was coated with an ethylene-vinyl acetate copolymer, manufactured by Hanwha Chemical Co., Ltd., EVA 2030 (having a melt index of 0.8 g measured at 190 캜 under a load of 2.16 kg 10 minutes, vinyl acetate content 6.5% by weight, density 0.927 g / cm 3, hereinafter referred to as 'C-2' in Table 3).

Epidermis
Composition ratio Bridging
Condition Heat shrinkage in MD direction after crosslinking
(%) Tensile modulus after crosslinking
(kg / cm ² ) Vacuum Skin Packer Test MD direction / TD direction Hotplate release Break frequency /
Number of tests Component A: Component B (% by weight) Component C
(Parts by weight) Example 4 A-1: B-1 =
80:20 - I 17 85/73 Good 0/10 Example 5 A-1: B-1 =
80:20 - II 14 86/78 Good 0/10 Example 6 A-2: B-2 =
85:15 - II 13 86/77 Good 0/10 Example 7 A-1: B-1 =
95: 5 - I 19 84/71 Good 0/10 Example 8 A-1: B-1 =
70:30 - I 15 87/75 Good 0/10 Example 9 A-1: B-1 =
60:40 - I 10 89/80 Good 0/10 Example 10 A-2: B-2 =
85:15 C-2
10 II 11 88/81 Good 0/10 Example 11 A-2: B-2 =
85:15 C-2
30 II 10 91/89 Good 0/10 Comparative Example 2 A-1 = 100 I 20 84/75 Sticking
(Sealing part and heating plate) 5/10 Comparative Example 3 A-1 = 100 II 18 87/80 Sticking
(Sealing part) 3/10

As shown in Table 3, the multilayered film using the high modulus resin composition of the present invention of the present invention overcomes the high heat shrinkage when the ionomer resin of the comparative example is used alone, and the low heat resistance to stick to the heat plate or sealing part And it is confirmed that the film is much more suitable as a film for packaging a vacuum skin since no breakage occurs.

Accordingly, the high-elasticity and heat-resistant resin composition and the film containing the same of the present invention have a low heat shrinkage at high temperatures and high heat resistance, so that thermal wrinkling does not easily occur during packaging of the vacuum skin, And can be applied to a vacuum skin packing film in an automatic packaging machine.

As described above, the present invention has been described with respect to the high elasticity and heat resistant resin composition and the product including the same by means of the specified matters and the limited embodiments. However, the present invention has been made in order to better understand the present invention. The present invention is not limited thereto, and various modifications and changes may be made thereto by those skilled in the art to which the present invention belongs.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (10)

(a) a first ionomer resin comprising an ethylene- (meth) acrylate,
(b) a modified polymer obtained by the reaction of a polyamide oligomer with a second ionomer resin composed of an ethylene- (meth) acrylate, and
Ethylene-vinyl acetate copolymer,
Wherein the first ionomer resin and the second ionomer resin satisfy the following formula (1).
[Formula 1]
MFR ₁ < MFR ₂
In the above formula (1), MFR ₁ is the melt flow rate of the first ionomer resin and MFR ₂ is the melt flow rate of the second ionomer resin. The method according to claim 1,
The high-elasticity and heat-resistant resin composition contains 1 to 20 parts by weight of an ethylene-vinyl acetate copolymer per 100 parts by weight of the resin composition comprising 70 to 99% by weight of the first ionomer resin and 1 to 30% by weight of the modified polymer A high elasticity and heat resistant resin composition. 3. The method of claim 2,
Wherein the ethylene-vinyl acetate copolymer has a vinyl acetate content of 10% by weight or less. delete The method according to claim 1,
Wherein the modified polymer has a content of the second ionomer resin: polyamide oligomer in a weight ratio of 10:90 to 90:10. The method according to claim 1,
Wherein the first ionomer resin and the second ionomer resin are obtained by converting part of the carboxyl groups of the ethylene- (meth) acrylic acid copolymer having an ethylene content of 10 to 95 mol% to a salt,
Wherein the first ionomer resin has a melt flow rate measured at 190 占 폚 and 2.16 kg of 0.1 to 3.0 g / 10 min, the second ionomer resin has a melt flow rate of 3.0 to 20.0 g / 10 minutes, and the difference between the melt flow rates of the first ionomer resin and the second ionomer resin is at least 1 g / 10 minutes. The method according to claim 1,
Wherein the polyamide oligomer has a weight average molecular weight of 500 to 5,000 g / mol. A single layer or a laminate of two or more layers made of the high-elasticity and heat-resistant resin composition of any one of claims 1 to 3 and 5 to 7. A multilayer film for packaging a vacuum skin, comprising the film of claim 8 as a skin layer and including a gas barrier layer. 10. The method of claim 9,
Wherein the vacuum skin packaging multilayer film is crosslinked by irradiating an electron beam.