Aluminum plastic film and base material used for aluminum plastic film

Abstract

To provide an aluminum plastic film and a base material used in the aluminum plastic film.SOLUTION: An aluminum plastic film 1 contains a base material 2 composed of a polyester layer, a composite resin layer and a polyamide layer, and an aluminum metal layer 3. The composite resin layer is installed between the polyester layer and the polyamide layer, and the aluminum metal layer is installed in the polyamide layer. The base material 2 composed of the polyester layer, the composite resin layer and the polyamide layer is integrally molded by coextrusion. The composite resin layer contains a terpolymer and a polyolefin resin, and, based on a total weight of the composite resin layer of 100 wt.%, a content of the terpolymer exceeds 45 wt.%, and the terpolymer contains a constitutional unit of ethylene-butyl acrylate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an aluminum plastic film and a base material used for the aluminum plastic film, and particularly to an aluminum plastic film applied to a battery and a base material used for the aluminum plastic film.

Background Art

[0002] It is difficult for a single material to achieve ideal protection as a packaging material. Therefore, most of the packaging materials on the market are composed of multi-layer films, and an ideal protection effect can be obtained by combining different films.

[0003] General processes for manufacturing multi-layer films include coating and lamination processes. However, an adhesive layer needs to be used for various layer combinations, and the solvents required for the adhesive layer may be harmful to the environment. Therefore, there is still room for improvement in the manufacturing process of conventional packaging materials.

[0004] In addition to protection, the adhesiveness between multi-layer films is also a function that should be emphasized in packaging materials. Depending on the use of the packaging, the adhesive strength expected by the market also varies.

[0005] For example, when the packaging material is used as a package for a battery pack and an electrolyte solution, the packaging material needs to have a certain degree of heat resistance, insulation, flexibility, electrolyte resistance, and tensile strength so as to be applicable to various processing steps in the battery process.

[0006] Therefore, by improving the material, it is an important issue for this industry to give an ideal protection effect to the packaging material, improve the adhesiveness between multi-layer films, and overcome the drawback that the solvent is not environmentally friendly according to each application purpose.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The technical problem to be solved by the present invention is to provide an aluminum-plastic film and a base material used for the aluminum-plastic film to address the deficiencies of the prior art.

Means for Solving the Problem

[0008] To solve the above technical problem, one technical means adopted by the present invention is to provide an aluminum-plastic film including a polyester layer, a composite resin layer, a polyamide layer, and an aluminum metal layer. The composite resin layer is installed between the polyester layer and the polyamide layer, and the aluminum metal layer is installed on the polyamide layer. The polyester layer, the composite resin layer, and the polyamide layer are integrally formed by coextrusion. The composite resin layer includes a terpolymer and a polyolefin resin. Taking the total weight of the composite resin layer as 100% by weight, the content of the terpolymer exceeds 45% by weight, and the terpolymer includes structural units of ethylene-butyl acrylate.

[0009] In one embodiment, the terpolymer is a copolymer synthesized from an ethylene monomer, a butyl acrylate monomer, and an acrylic monomer.

[0010] In one embodiment, taking the total weight of the terpolymer as 100% by weight, the total weight of the ethylene monomer and the butyl acrylate monomer in the terpolymer is 14 wt% - 20 wt%.

[0011] In one embodiment, maleic anhydride is grafted onto the terpolymer.

[0012] In one embodiment, a maleic anhydride functional group is grafted onto the ethylene monomer, and the grafting rate of maleic anhydride is 5 wt% - 15 wt%.

[0013] In one embodiment, the ratio of terpolymer to polyolefin resin (by weight) in the composite resin layer is 1:1 - 3:1.

[0014] In one embodiment, the component of the polyester layer is polyethylene terephthalate, the intrinsic viscosity of the polyethylene terephthalate is 0.60 to 0.68, and the melting point of the polyethylene terephthalate is 240°C to 250°C.

[0015] In one embodiment, the number average molecular weight of the material forming the polyamide layer is 20,000 g / mol to 23,000 g / mol, the relative viscosity of the material forming the polyamide layer is 2.7 to 2.9, and the melting point of the material forming the polyamide layer is 215°C to 225°C.

[0016] To solve the above technical problems, another technical means adopted by the present invention is to provide a base material for use in an aluminum-plastic film. The base material for use in an aluminum-plastic film provides a base material for use in an aluminum-plastic film, including a polyester layer, a composite resin layer, and a polyamide layer. The composite resin layer is installed between the polyester layer and the polyamide layer, and the polyester layer, the composite resin, and the polyamide layer are integrally formed by coextrusion. The composite resin includes a terpolymer and a polyolefin resin. Taking the total weight of the composite resin as 100% by weight, the content of the terpolymer exceeds 45% by weight, and the terpolymer includes structural units of ethylene-butyl acrylate.

[0017] In one embodiment, the haze value of the base material for use in an aluminum-plastic film is less than 5%.

Advantages of the Invention

[0018] As an advantageous effect of the present invention, the aluminum-plastic film and the base material for use in an aluminum-plastic film according to the present invention are given transparency and good adhesiveness to the aluminum-plastic film and the base material for use in an aluminum-plastic film by technical features such as "taking the total weight of the composite resin layer as 100% by weight, the content of the terpolymer exceeds 45% by weight", "the terpolymer includes structural units of ethylene-butyl acrylate", and "the polyester layer, the composite resin layer, and the polyamide layer are integrally formed by coextrusion".

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0020] For a better understanding of the features and technical content of the present invention, please refer to the following detailed description of the present invention and the accompanying drawings. However, the provided accompanying drawings are only for reference and explanation, and are not for limiting the scope of the claims of the present invention.

[0021] Hereinafter, embodiments of the present invention will be described by the "aluminum plastic film and the base material used for the aluminum plastic film" according to a predetermined specific embodiment, and those skilled in the art can understand the advantages and effects of the present invention based on the content disclosed in this specification. The present invention can be implemented or applied by other different specific embodiments, and for each detail in this specification, various modifications and changes can be made based on different viewpoints and uses without departing from the concept of the present invention. Also, as described in advance, the accompanying drawings of the present invention are simple schematic explanations and are not drawn based on actual sizes. The technical content of the present invention will be described in more detail based on the following embodiments, but the disclosed content does not limit the protection scope of the present invention. Also, the term "or" used in this specification may include any one or a combination of more than one of the related items according to the actual situation.

[0022] As shown in FIG. 1 which is a schematic side view of the aluminum-plastic film according to the present invention, the aluminum-plastic film 1 includes a base material 2 used for the aluminum-plastic film and an aluminum metal layer 3. The aluminum metal layer 3 may be installed on the base material 2 used for the aluminum-plastic film by an adhesion method, but the present invention is not limited thereto. That is, as long as the aluminum metal layer 3 can be fixed to the base material 2 used for the aluminum-plastic film, the fixing method is not limited.

[0023] In the present invention, the base material 2 used for the aluminum-plastic film is integrally formed by co-extrusion. When manufacturing the base material 2 used for the aluminum-plastic film, it is not necessary to apply an adhesive. Since no adhesive is used, it is not necessary to use a solvent-based solution, and layer peeling due to the deterioration of the adhesive does not occur. Therefore, the base material 2 used for the aluminum-plastic film has the advantages of a simple process and environmental friendliness.

[0024] As shown in FIG. 2 which is a schematic side view of the base material 2 used for the aluminum-plastic film according to the present invention, the base material 2 used for the aluminum-plastic film includes a polyester layer 21, a composite resin layer 22, and a polyamide layer 23.

[0025] When applied to the outer packaging material of a battery, since the polyester layer 21 is in contact with the electrolyte, the polyester layer 21 needs to have good electrolyte liquid resistance and heat resistance. Since the polyamide layer 23 is in contact with the aluminum metal layer 3, the polyamide layer 23 needs to have good penetration resistance in order to protect other layers and ensure the safety of battery use. In one exemplary case, the thickness of the aluminum metal layer is 15 μm to 45 μm, but the present invention is not limited thereto.

[0026] Due to the differences in the properties of the materials, polyester and polyamide cannot be joined by heat fusion. When polyester and polyamide are directly co-extruded, the materials will delaminate, so a composite film cannot be formed. Therefore, by using a specific composite resin material in the present invention, a composite resin layer 22 is formed between the polyester layer 21 and the polyamide layer 23. The composite resin layer 22 can adhere to each of the polyester layer 21 and the polyamide layer 23 so as to provide sufficient peel strength and appropriate tensile strength to the base material 2 used for the aluminum plastic film.

[0027] In addition, the composite resin layer 22 needs to have high transparency and a low haze value so as to provide high transparency and a low haze value to the base material 2 used for the aluminum plastic film. In this way, it is easy to check whether there are defects in the aluminum plastic film 1 after punching and to check whether the barcode on the aluminum metal layer 3 is clear, so as to facilitate quality control.

[0028] In the present invention, the material forming the composite resin layer 22 contains a polar terpolymer. By adding the terpolymer, good adhesiveness is imparted to the polyester layer 21, the composite resin layer 22, and the polyamide layer 23.

[0029] The terpolymer contains structural units of ethylene-butyl acrylate. That is, among the monomers for synthesizing the terpolymer, ethylene and butyl acrylate are included.

[0030] In one example, the terpolymer is a copolymer synthesized from an ethylene monomer, a butyl acrylate monomer, and an acrylic monomer, and is formed by a copolymerization reaction simultaneously with these three monomers. In this way, the terpolymer has polarity, and the composite resin layer 22 has good adhesiveness with the polyester layer 21 and the polyamide layer 23 at the same time, but the present invention is not limited thereto.

[0031] To improve adhesion, the total content of ethylene monomer and butyl acrylate in the terpolymer can be controlled. In one exemplary embodiment, with the total weight of the terpolymer being 100 wt%, the total content of ethylene monomer and butyl acrylate in the terpolymer is 14 wt% to 20 wt%. For example, the content of butyl acrylate in the monomers for synthesizing the terpolymer may be 15 wt%, 16 wt%, 17 wt%, 18 wt%, or 19 wt%.

[0032] In one exemplary embodiment, the Shore hardness of the terpolymer is 85A to 90A. The melt index of the terpolymer measured under the condition of 190 °C / 2.16 kg is 6.5 to 7.5.

[0033] To further improve adhesion, maleic anhydride segments are grafted onto the terpolymer. In one exemplary embodiment, the terpolymer is synthesized using an ethylene monomer onto which maleic anhydride segments are grafted. Specifically, the grafting rate of maleic anhydride onto ethylene is 5 wt% to 15 wt%.

[0034] In the composite resin layer 22, in order to achieve good adhesion, it is necessary to contain a certain amount of terpolymer. Specifically, with the total weight of the composite resin layer 22 being 100 wt%, the content of the terpolymer in the composite resin layer 22 is 45 wt% or more.

[0035] Preferably, the content of the terpolymer in the composite resin layer 22 is 50 wt% or more. For example, the content of the terpolymer in the composite resin layer 22 may be 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt% or 100 wt%.

[0036] In addition to the terpolymer, the material for forming the composite resin may further include a polyolefin resin. By adding the polyolefin resin, the cost can be reduced and the stretchability of the composite resin layer 22 can be improved, which is advantageous for the subsequent stretching process. It should be noted that the content of the terpolymer in the composite resin layer 22 still needs to be 45% by weight or more.

[0037] In one exemplary embodiment, the polyolefin resin is low-density polyethylene. Since the polyolefin resin has good compatibility with the terpolymer, it is advantageous for the formation of the composite resin layer 22. Here, the polyolefin resin is preferably low-density polyethylene. Also, the substrate 2 used for the aluminum plastic film has the characteristics of high transparency and a low haze value.

[0038] In one embodiment, in the polyester layer 21, polyethylene terephthalate with a melting point of 240°C to 250°C is used, and the intrinsic viscosity of the polyethylene terephthalate is 0.60 to 0.68. In the polyamide layer 23, it is nylon 6 (also called polycaprolactam) with a molecular weight of 20,000 g / mol to 23,000 g / mol. The relative viscosity of nylon 6 is 2.7 to 2.9, the melting point of nylon 6 is 215°C to 225°C, and the peroxide value of nylon 6 is 42 ± 2 meq / kg.

[0039] When manufacturing the substrate 2 used for the aluminum plastic film, it includes at least the step of drying the raw materials (step S1), the step of co-extruding a three-layer composite laminate using the raw materials (step S2), the step of biaxially stretching the composite laminate to a desired thickness (step S3), the step of heat-fixing the stretched composite laminate to manufacture the substrate 2 used for the aluminum plastic film (step S4), and the step of winding up the substrate 2 used for the aluminum plastic film after cooling (step S5).

[0040] To explain the effects of the present invention, the base material 2 used for the aluminum plastic films of Example 1, Example 2, and Comparative Example 1 was manufactured based on the above steps S1 to S5, and the differences and characteristic results thereof are as shown in Table 1.

[0041] [Example 1] In step S1, polyethylene terephthalate (hereinafter referred to as PET), a composite resin material (a material for forming the composite resin layer 22), and nylon 6 were dried for 6 to 8 hours in an environment with a temperature of 110°C to 130°C and a dew point of -40°C. In the composite resin material, the weight ratio of the terpolymer and low-density polyethylene (hereinafter referred to as LDPE) is 1:1. The terpolymer (hereinafter referred to as EBA-AA) is a copolymer formed by copolymerizing ethylene monomer, butyl acrylate monomer, and acrylic monomer. Here, 5 wt% to 15 wt% of maleic anhydride is grafted onto the ethylene monomer. In this specification, the definition of the grafting rate is (weight after grafting - weight before grafting) / (weight before grafting) × 100%.

[0042] In step S2, in a three-layer coextrusion device, the polyester layer 21, the composite resin layer 22, and the polyamide layer 23 were formed in this order at screw processing temperatures of 260°C, 250°C, and 250°C, respectively. The temperature of the feedblock was 250°C. The thicknesses of the three layers of the polyester layer 21, the composite resin layer 22, and the polyamide layer 23 formed by extrusion were 40 μm, 16 μm, and 144 μm, respectively. The total thickness of the composite laminate was 200 μm.

[0043] After performing biaxial stretching in step S3, the thicknesses of the polyester layer 21, the composite resin layer 22, and the polyamide layer 23 were 5 μm, 2 μm, and 18 μm, respectively. The total thickness of the base material 2 used for the aluminum plastic film was 25 μm.

[0044] Using a haze value and transmittance measuring instrument (product number: X-rite color eye 7000A) manufactured by X-Rite in the United States, based on the standard test method ASTM D1003 specified by the American Society for Testing and Materials, the haze value and visible light transmittance of the substrate 2 used for the aluminum plastic film were measured. According to the results, the haze value of the substrate 2 used for the aluminum plastic film was 3.7%, and the visible light transmittance of the substrate 2 used for the aluminum plastic film was 91.6%.

[0045] Using a tensile strength testing machine (product number: Shimadzu AG-X), based on the standard test method ASTM D882 specified by the American Society for Testing and Materials, the tensile strength of the substrate 2 used for the aluminum plastic film was measured. According to the results, the tensile strength of the substrate 2 used for the aluminum plastic film was 9.7 kg / cm 2 It was.

[0046] Also, in order to evaluate the interlayer adhesion strength of the substrate 2 used for the aluminum plastic film, the substrate 2 used for the aluminum plastic film was torn by hand, and its cross-section showed a jagged shape. That is, in Example 1, the interlayer adhesion strength was relatively weak.

[0047] [Example 2] The raw materials and operation methods used in Example 2 were similar to those in Example 1. Regarding their differences, the terpolymer (copolymer of ethylene, butyl acrylate, and acrylic acid) : low-density polyethylene (weight ratio) in the composite resin material was 3:1.

[0048] In Example 2, the total thickness of the substrate 2 used for the aluminum plastic film was 25 μm. According to the measurement, the haze value of the substrate 2 used for the aluminum plastic film was 1.2%, the visible light transmittance of the substrate 2 used for the aluminum plastic film was 91.3%, and the tensile strength of the substrate 2 used for the aluminum plastic film was 12.4 kg / cm 2It was so. The substrate 2 used for the aluminum plastic film was torn by hand, and its cross-section was smooth. That is, in Example 2, the interlayer adhesion strength was good.

[0049] [Comparative Example 1] The raw materials and operation methods used in Comparative Example 1 were similar to those in Example 2. Regarding their differences, polyethylene terephthalate was added to the composite resin material and mixed with the terpolymer. The weight ratio of the terpolymer (copolymer of ethylene, butyl acrylate, and acrylic acid) to polyethylene terephthalate in the composite resin material was 3:1.

[0050] In Comparative Example 1, the total thickness of the substrate 2 used for the aluminum plastic film was 25 μm. According to the measurement, the haze value of the substrate 2 used for the aluminum plastic film was 25.7%, the visible light transmittance of the substrate 2 used for the aluminum plastic film was 93.5%, and the tensile strength of the substrate 2 used for the aluminum plastic film was 13.6 kg / cm 2 It was so. The substrate 2 used for the aluminum plastic film was torn by hand, and its cross-section was basically smooth but had a little unevenness. That is, in Comparative Example 1, the interlayer adhesion strength was mediocre.

[0051] [Table 1] TIFF0007701957000001.tif73125

[0052] According to the experimental results, when the content of the terpolymer in the composite resin layer 22 was 45% by weight or more, the composite resin layer 22 was formed by coextrusion, adhered to each of the polyester layer 21 and the polyamide layer 23, and had good adhesion strength. Therefore, the present invention can avoid the drawback that it is necessary to use secondary processing or an adhesive layer when manufacturing a conventional composite film, and has the advantage of being easy to use for processing manufacturers (such as companies responsible for downstream processes).

[0053] In addition, the installation of the composite resin layer 22 does not adversely affect the visible light transmittance of the base material 2 used for the aluminum plastic film. Specifically, the visible light transmittance of the base material used for the aluminum plastic film exceeds 90%.

[0054] When mixing the polyolefin resin and the terpolymer, not only can the cost be reduced, but also the stretchability of the composite resin layer 22 can be improved. According to the results in Table 1, since the tensile strength of the base material 2 used for the aluminum plastic film according to Examples 1 and 2 is lower than the tensile strength of the base material 2 used for the aluminum plastic film according to Comparative Example 1, the stretchability of the composite resin layer 22 can be improved by adding the polyolefin resin. Specifically, the tensile strength of the base material 2 used for the aluminum plastic film according to the present invention is 8 kg / cm 2 ~13 kg / cm 2 was.

[0055] In addition, adding polyolefin resin gives a lower haze value to the base material 2 used for the aluminum plastic film than adding polyterephthalic acid, and it can be applied to multiple uses. Specifically, the haze value of the base material 2 used for the aluminum plastic film is less than 5%, preferably less than 4%, and more preferably less than 3%.

[0056] [Advantageous effects according to the embodiment] As an advantageous effect of the present invention, the aluminum plastic film and the base material used for the aluminum plastic film according to the present invention have transparency and good adhesiveness due to technical features such as "taking the total weight of the composite resin as 100% by weight and the content of the terpolymer exceeding 45% by weight", "the terpolymer contains structural units of ethylene-butyl acrylate", and "the polyester layer, the composite resin layer, and the polyamide layer are integrally formed by coextrusion".

[0057] More specifically, the materials used in the present invention are selected for application to battery packaging materials. The terpolymer used has high transparency and a low haze value, and at the same time has good adhesiveness with polyester and polyamide. Therefore, the base material used for the aluminum-plastic film according to the present invention can be directly manufactured by coextrusion, and thus has the advantage of simple manufacturing.

[0058] In order to improve the adhesiveness, in the present invention, a terpolymer containing at least an ethylene monomer and a butyl acrylate monomer is used, and the weight ratio of butyl acrylate in the monomers for synthesizing the terpolymer is controlled. Further, when ethylene, butyl acrylate, and acrylic acid are used as the monomers for synthesizing the terpolymer, the terpolymer has good adhesiveness with both polyester and polyamide. Also, a terpolymer grafted with maleic anhydride may be used.

[0059] On the other hand, also in the present invention, in order to improve the interlayer adhesion strength and the characteristics of the aluminum-plastic film (for example, electrolyte liquid resistance, heat resistance, and puncture resistance), the characteristics of the components of the polyester layer and the polyamide layer are controlled.

[0060] The content disclosed above is only a preferred practicable embodiment of the present invention, and the scope of the claims of the present invention is not limited thereto. Therefore, all equivalent technical changes made using the content of the specification and drawings of the present invention are included in the scope of the claims of the present invention.

Description of Reference Numerals

[0061] 1 Aluminum-plastic film 2 Base material used for the aluminum-plastic film 21 Polyester layer 22 Composite resin layer 23 Polyamide layer 3 Aluminum metal layer

Claims

1. A polyester layer whose component is polyethylene terephthalate, a composite resin layer composed of a terpolymer and low-density polyethylene, a polyamide layer, an aluminum metal layer provided on the polyamide layer, an aluminum-plastic film comprising: the composite resin layer is provided between the polyester layer and the polyamide layer, taking the total weight of the composite resin layer as 100% by weight, the content of the terpolymer exceeds 45% by weight, and the terpolymer is a copolymer synthesized from an ethylene monomer, a butyl acrylate monomer, and an acrylic monomer, the polyester layer, the composite resin layer, and the polyamide layer are integrally formed by coextrusion, and the number average molecular weight of the material forming the polyamide layer is 20,000 g / mol to 23,000 g / mol, characterized by an aluminum-plastic film.

2. Taking the total weight of the terpolymer as 100% by weight, the total weight of the ethylene monomer and the butyl acrylate monomer in the terpolymer is 14 wt% to 20 wt%, the aluminum-plastic film according to claim 1.

3. An aluminum-plastic film according to claim 1, wherein a maleic anhydride functional group is grafted onto the terpolymer.

4. An aluminum-plastic film according to claim 1, wherein a maleic anhydride functional group is grafted onto the ethylene monomer, and the grafting rate of the maleic anhydride functional group in the ethylene monomer is 5 wt% to 15 wt%.

5. The aluminum-plastic film according to claim 1, wherein the terpolymer: the low-density polyethylene (weight ratio) in the composite resin layer is 1:1 to 3:

1.

6. The intrinsic viscosity of the polyethylene terephthalate is 0.60 to 0.68, and the melting point of the polyethylene terephthalate is 240 °C to 250 °C, the aluminum-plastic film according to claim 1.

7. The relative viscosity of the material forming the polyamide layer is 2.7 to 2.9, and the melting point of the material forming the polyamide layer is 215 °C to 225 °C, the aluminum-plastic film according to claim 1.

8. A polyester layer whose component is polyethylene terephthalate, a composite resin layer composed of a terpolymer and low-density polyethylene, a base material used for an aluminum-plastic film comprising a polyamide layer, The composite resin layer is disposed between the polyester layer and the polyamide layer, Taking the total weight of the composite resin layer as 100% by weight, the content of the terpolymer exceeds 45% by weight, and the terpolymer is a copolymer synthesized from an ethylene monomer, a butyl acrylate monomer, and an acrylic monomer. The polyester layer, the composite resin layer, and the polyamide layer are formed by coextrusion molding, and the number average molecular weight of the material forming the polyamide layer is 20,000 g / mol to 23,000 g / mol. A base material used for an aluminum-plastic film, characterized in that.

9. A base material used for the aluminum-plastic film according to claim 8, wherein the haze value is less than 5%.

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