Kettle-type sterilization film laminated material and packaging material containing kettle-type sterilization film laminated material

Abstract

A kettle sterilization film laminate according to one embodiment of the present invention includes a first OPP film formed from oriented polypropylene (OPP); a first CPP film formed of cast polypropylene (CPP) and laminated on one surface of the first OPP film; a second OPP film formed of oriented polypropylene and laminated on one surface of the first CPP film; and a second CPP film formed of cast polypropylene and laminated on one surface of the second OPP film.

Description

Technical Field

[0001] The present invention relates to a retort sterilization film laminate and a packaging material including the same, and more particularly, to a retort sterilization film laminate capable of maintaining interlayer bonding strength even after retort sterilization, and a packaging material including the same. Background Art

[0002] It is known that the retort pouch packaging material consists of a layer structure of a laminated film made of a single material PP (polypropylene) material, rather than a layer structure of a laminated film made of existing heterogeneous materials (eg, PET, Al, Ny, PP, etc.).

[0003] Due to the hard and brittle nature of PP material, laminated films made of single material PP have limitations in transporting heavy products. In addition, since non-polar single material PP is laminated, laminated films made of single material PP will cause the problem of reduced interlayer bonding strength after autoclave sterilization. The reduction in interlayer bonding strength weakens the peel strength and impact strength of the laminated film. Summary of the invention

[0004] Technical issues

[0005] One object of the present invention is to provide a kettle-sterilized film laminate having enhanced interlayer bonding strength. Another object of the present invention is to provide a kettle-sterilized film laminate that prevents breakage during transportation. Another object of the present invention is to provide a packaging material comprising the kettle-sterilized film laminate.

[0006] Technical Solution

[0007] A kettle sterilization film laminate according to one embodiment of the present invention includes a first OPP film, which is formed of oriented polypropylene (OPP); a first CPP film, which is formed of cast polypropylene (CPP) and laminated on one surface of the first OPP film; a second OPP film, which is formed of oriented polypropylene and laminated on one surface of the first CPP film; and a second CPP film, which is formed of cast polypropylene and laminated on one surface of the second OPP film.

[0008] At least one of the first OPP film and the second OPP film may be formed as a barrier-type OPP film that blocks oxygen or moisture.

[0009] The barrier type OPP film may be formed as a transparent film on which AlOx is deposited.

[0010] The barrier type OPP film may be formed as a transparent film on which a SiOx type inorganic material is deposited.

[0011] The first CPP film may have surface irregularities by performing corona treatment on both surfaces.

[0012] The first CPP film and the second CPP film may have a thickness ratio of 1:1 to 1:2.5.

[0013] The first CPP film and the second CPP film may contain a rubber component.

[0014] A dry laminate layer may be provided between each of the first OPP film, the first CPP film, the second OPP film, and the second CPP film.

[0015] A packaging material according to one embodiment of the present invention includes an autoclave-sterilized film laminate, a first film laminate forming one side in the thickness direction of the packaging material, a second film laminate forming the other side in the thickness direction of the packaging material, and a sealing portion forming the periphery of the first film laminate and the second film laminate, wherein the sealing portions are bonded by second CPP films facing each other.

[0016] The thickness of the second CPP film in the sealing portion may be formed to be greater than the thickness of the first CPP film disposed between the first OPP film and the second OPP film.

[0017] Beneficial Effects

[0018] In this manner, one embodiment of the present invention provides the first CPP film between the first OPP film and the second OPP film, thereby enhancing interlayer adhesive strength and preventing breakage during transportation.

[0019] In one embodiment, a first CPP film and a second CPP film are provided, so that the total thickness of the film laminate can be kept the same while enhancing the interlayer bonding strength. The sealing portion is formed by the second CPP film containing a rubber component, so that the sealing property of the packaging material can be maintained.

[0020] Furthermore, in one embodiment, the second CPP film is formed thicker than the first CPP film, thereby improving and maintaining the sealing property of the sealing portion of the packaging material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a cross-sectional structural diagram of an autoclave-type sterilization film laminate according to one embodiment of the present invention.

[0022] Figure 2 is a perspective view of a packaging material comprising an autoclave film laminate according to one embodiment of the present invention.

[0023] Figure 3 is along Figure 2A sectional view taken along line III-III. DETAILED DESCRIPTION

[0024] Best Mode for Carrying Out the Invention

[0025] The present invention will be described more fully below with reference to the accompanying drawings, in which embodiments of the present invention are shown. As will be appreciated by those skilled in the art, the described embodiments may be modified in a variety of ways without departing from the spirit or scope of the present invention. The accompanying drawings and descriptions are to be considered illustrative in nature, rather than restrictive. Throughout the specification, the same reference numerals designate the same elements.

[0026] Figure 1 2 is a cross-sectional view of a kettle-type sterilization film laminate according to one embodiment of the present invention. Figure 1 The autoclave-sterilized film laminate material 100 of one embodiment includes a first OPP film 11 , a first CPP film 21 , a second OPP film 12 , and a second CPP film 22 .

[0027] The first OPP film 11, the first CPP film 21, the second OPP film 12, and the second CPP film 22 are laminated to each other with the dry laminate layer DL interposed between the respective films. The first OPP film 11 may have a printed layer.

[0028] The first OPP film 11, the first CPP film 21, the second OPP film 12, and the second CPP film 22 are formed of a single material to ensure excellent recyclability and form a film laminate 100 suitable for retort applications, in which material use is limited due to a heat treatment process and substitution is difficult.

[0029] The first OPP film 11 and the second OPP film 12 are formed of oriented polypropylene (OPP) For example, the first OPP film 11 and the second OPP film 12 may each have a thickness of 15 to 30 μm.

[0030] The first OPP film 11 is formed Figure 1 The first substrate of the top layer provides the property of enabling printing and provides heat resistance to prevent thermal damage. The second OPP film 12 is the third substrate forming the third layer from the top, which enhances and maintains strength.

[0031] At least one of the first OPP film 11 and the second OPP film 12 may be formed as a barrier type OPP film that blocks oxygen or moisture. For example, the first OPP film 11 and the second OPP film 12 may each have a thickness of 15 to 30 μm.

[0032] When the first OPP film 11 as the first substrate is formed as a barrier type OPP film (the barrier type OPP film has a barrier property to block oxygen or moisture), it provides printing capability and provides heat resistance to prevent heat damage during autoclave sterilization and sealing.

[0033] For example, the barrier OPP film can be formed as a transparent film deposited with AlOx. In addition, the barrier OPP film can also be formed as a transparent film deposited with SiOx type inorganic materials. In addition, the barrier OPP film can also be formed as a transparent film deposited with an organic-inorganic hybrid type, combining an organic compound with AlOx or SiOx to improve the hard and brittle properties of the inorganic material.

[0034] In addition, the barrier OPP film may be formed as a transparent film including a barrier coating material or improving barrier properties by mixing a plate-like substance such as nanoclay. The barrier OPP film may also be formed as an OPP-based barrier film.

[0035] The first CPP film 21 and the second CPP film 22 are formed of cast polypropylene (CPP). For example, the first CPP film 21 and the second CPP film 22 are used for kettle applications and may have a combined thickness of 60 to 120 μm. The first CPP film 21 and the second CPP film 22 are used for kettle applications and contain a rubber component for impact resistance reinforcement.

[0036] The first CPP film 21 is a second base forming a second layer from the top, which contains a rubber component to enhance impact strength. The second CPP film 22 is a fourth base forming a fourth layer from the top, which improves sealing and anti-orange peel properties. That is, since sealing adhesion is essential for the second CPP film 22, the second CPP film 22 may contain a larger amount of rubber components than the first CPP film 21, which enables smooth sealing at low temperatures.

[0037] After the film laminate undergoes autoclave sterilization (usually at 121°C), the heat resistance of the film laminate deteriorates. When the heat resistance deteriorates, the contents in the film laminate permeate into the film laminate, causing the film laminate to become uneven like orange peel, which significantly reduces the appearance quality of the film laminate product.

[0038] Orange peel resistance is a term used in the packaging and film industries, referring to the performance of a film laminate material that maintains its appearance quality without deterioration. Due to the rubber component, the second CPP film 22 can improve sealing properties and orange peel resistance.

[0039] Note that the first CPP film 21 has surface irregularities on both surfaces by corona treatment on both surfaces, and one surface is laminated to one surface of the first OPP film 11 , and the other surface is laminated to one surface of the second OPP film 12 .

[0040] The corona treatment not only produces physical irregularities on the surface of the non-polar first CPP film 21, but also oxidizes and polarizes the surface by discharge. Therefore, the first CPP film 21 improves the adhesion between the first OPP film 11 and the second OPP film 12, and the physical adhesion can be further improved by the surface irregularities.

[0041] That is, the first OPP film 11 and the second OPP film 12 have very smooth and highly flat surfaces due to stretching, so that the surfaces can be polarized by corona treatment, while making it difficult to form physical irregularities, which leads to low adhesive strength. However, the first CPP film 21 is inserted between the first OPP film 11 and the second OPP film 12, so that the mutual adhesive strength on both surfaces can be increased.

[0042] The first CPP film 21 may be used with a minimum thickness to provide adhesion performance between the first OPP film 11 and the second OPP film 12 within a range capable of enhancing the required impact strength. The first CPP film 21 with a minimum thickness may provide excellent adhesion strength through surface irregularities and wetting tension of both surfaces generated by corona treatment.

[0043] Generally, in order to achieve a desired level of interlayer adhesive strength, the wetting tension of the film must be at least 36 dynes. By corona treatment on both surfaces, the first CPP film 21 has a wetting tension of 37 to 42 dynes, thereby enabling sufficient interlayer adhesive strength to be achieved.

[0044] That is, by performing corona discharge treatment on the first CPP film 21, free radicals, ions, etc. are generated on the surface to polarize it, thereby maximizing the adhesive strength of the bond. In addition, the corona treatment can simultaneously achieve a physical bonding effect by roughening the surface of the first CPP film 21 to generate irregularities thereon, thereby allowing more effective bonding.

[0045] The first CPP film 21 with high impact strength as a kettle CPP film can compensate for the hardness and easy breakage of the first OPP film 11 and the second OPP film 12. As shown in the figure, the sandwich structure (in which the first CPP film is located between the first OPP film 11 as the first substrate and the second OPP film 12 as the third substrate) mainly enables the first OPP film 11 as the first substrate to reduce the impact from falling or external force, thereby enhancing the overall strength of the kettle sterilization film laminate 100.

[0046] The second CPP film 22 is intended to provide sealing in the packaging material 200 using the film laminate 100, and can use a thickness within the combined thickness range of the first CPP film 21 and the second CPP film 22 and excluding the thickness of the first CPP film 21. The first CPP film 21 and the second CPP film 22 have a thickness ratio of 1:1 to 1:2.5. For example, when the thickness of the first CPP film 21 is 30 to 50 μm, the second CPP film 22 may have a thickness of 30 to 70 μm.

[0047] In one embodiment, compared to the related art using a single CCP film, the separate first CPP film 21 and the second CPP film 22 can improve the adhesion performance between the first OPP film 11 and the second OPP film 12 by using the same amount, i.e., the same thickness of the CPP film without causing an increase in thickness, and can enhance and maintain sealing because the second CPP film 22 is formed thicker than the first OPP film 11.

[0048] Figure 2 is a perspective view of a packaging material comprising an autoclave film laminate according to one embodiment of the present invention, Figure 3 is along Figure 2 A cross-sectional view taken along line III-III. Figure 2 and Figure 3 The packaging material 200 of one embodiment comprises Figure 1 Autoclave sterilized film laminate 100.

[0049] The packaging material 200 may be formed into a self-standing type (eg, a stand-up bag) and a non-self-standing type (eg, a three-side sealed bag), and for convenience, is shown here as a self-standing type.

[0050] In the packaging material 200, the first film laminate 110 forming one side and the second film laminate 120 forming the other side form a sealing portion 300 by attaching the upper second CPP film 22 and the lower second CPP film 22 facing each other internally. Figure 3 In the embodiment, the printed layer and the dry laminate layer are omitted.

[0051] That is, the sealing portion 300 is formed by symmetrically arranging the first film laminate 110 and the second film laminate 120 and attaching two facing second CPP films 22. The two facing second CPP films 22 can provide sufficient sealing for the sealing portion 300 of the packaging material 200.

[0052] Hereinafter, the excellent performance of the embodiment will be described by comparing the film laminate 100 of the embodiment with the film laminate of the comparative example. The film laminate of the comparative example includes the first OPP film of the embodiment, the second OPP film and a single CPP film (corresponding to the second CPP film of the embodiment and not having a configuration corresponding to the first CPP film).

[0053] The total thickness of the film laminate 100 of the embodiment and the film laminate of the comparative example is the same, and the combined thickness of the first CPP film 21 and the second CPP film 22 of the embodiment is the same as the thickness of the CPP film of the comparative example. That is, the total amount of materials used is the same. In the comparative example, the first substrate is an OPP film, the second substrate is an OPP film, and the third substrate is a CPP film.

[0054] [Table 1]

[0055]

[0056] In the embodiment, before autoclave sterilization, the interlayer bond strength between the first substrate and the second substrate is 310 gf / 15 mm 2 , the interlayer bonding strength between the second substrate and the third substrate is 225gf / 15mm 2 , the interlayer bonding strength between the third substrate and the fourth substrate is 240gf / 15mm 2 In the comparative example, before autoclave sterilization, the interlayer bonding strength between the first substrate and the second substrate was 190 gf / 15 mm 2 , the interlayer bonding strength between the second substrate and the third substrate is 205gf / 15mm 2 .

[0057] The interlayer adhesive strengths on both surfaces of the second substrate of the embodiment were 310 and 225 gf / 15 mm, respectively. 2 The interlayer adhesive strengths on both surfaces of the second substrate of the comparative example were 190 and 250 gf / 15 mm, respectively. 2 It can be seen that before autoclave sterilization, the bonding strength of the example is significantly better than that of the comparative example.

[0058] In the embodiment, after autoclave sterilization, the interlayer bond strength between the first substrate and the second substrate is 275 gf / 15 mm 2 , the interlayer bonding strength between the second substrate and the third substrate is 230gf / 15mm 2 , the interlayer bonding strength between the third substrate and the fourth substrate is 250gf / 15mm 2 In the comparative example, after autoclave sterilization, the interlayer bond strength between the first substrate and the second substrate was 205 gf / 15 mm 2, the interlayer bonding strength between the second substrate and the third substrate is 230gf / 15mm 2 .

[0059] The interlayer adhesive strengths on both surfaces of the second substrate of the embodiment were 275 and 230 gf / 15mm, respectively. 2 The interlayer adhesive strengths on both surfaces of the second substrate of the comparative example were 205 and 230 gf / 15mm, respectively. 2 It can be seen that even after autoclave sterilization, the interlayer bonding strength of the examples is significantly better than that of the comparative examples.

[0060] In the example where the first CPP film 21 and the second CPP film 22 were applied, it was confirmed that the interlayer adhesive strength was greatly increased both before and after autoclave sterilization, compared with the comparative example where a single CPP film was applied.

[0061] Note that when comparing the interlayer bonding strength between the respective materials, the embodiment having a CPP film between the OPP film and the OPP film can increase the interlayer bonding strength compared to the comparative example having a laminated structure between the OPP film and the OPP film, due to the wettability and the anchoring effect caused by the wettability caused by the surface irregularities of the CPP film.

[0062] [Table 2]

[0063]

[0064] Referring to the interlayer bonding strength between each material, the average interlayer bonding strength between OPP film and OPP film is 180gf / 15mm 2 The average interlayer bonding strength of OPP film and CPP film is 301gf / 15mm 2 The interlayer bonding strength between the OPP film and the CPP film is significantly higher than the interlayer bonding strength between the OPP film and the OPP film. The embodiment achieves high interlayer bonding strength between the first CPP film 21 and the first OPP film 11 and between the first CPP film 21 and the second OPP film 12, which is not shown in the comparative example.

[0065] Hereinafter, the superior performance of the embodiment will be described by comparing the packaging material 200 to which the film laminate 100 of the embodiment is applied and the packaging material of the comparative example. When the film laminate 100 is applied to the packaging material, the ratio of the thickness of each layer to the total thickness can be changed to improve the heating efficiency.

[0066] At the upper end of the film laminate 100, i.e., the outer side of the packaging material 200, the first OPP film 11 and the second OPP film 12 as high-strength material layers are formed thicker than the first CPP film 21 and the second CPP film 22. The lower end of the film laminate 100, i.e., the inner side of the packaging material 200, includes a kettle layer having a large influence on heating efficiency. The second CPP film 22 arranged inside the kettle layer is formed thicker than the first CPP film 21 arranged in the middle.

[0067] Increases in interlayer adhesive strength and impact strength are ensured by the surface characteristics of the first and second OPP films 11 and 12 and the first and second CPP films 21 and 22, and transportation stability can be achieved while ultimately using the same or similar amount of PP raw materials.

[0068] However, for transportation stability, the thicknesses of the first and second OPP films 11 and 12 and the first and second CPP films 21 and 22 and their ratios may be increased or decreased according to the transportation environment to adjust general physical properties other than interlayer adhesive strength, such as tensile strength and sealing strength.

[0069] The autoclave sterilization efficiency of the packaging material 200 was confirmed. The dart drop impact strength, which is an index for predicting impact strength and transportation stability based on the improvement of interlayer adhesion strength, was used. It was confirmed that the dart drop impact strength in the example increased compared with the comparative example, and even after autoclave sterilization, the dart drop impact strength in the example was similarly maintained compared with the comparative example.

[0070] The dart drop impact strength is the strength of impact resistance of the film laminate 100 and the packaging material 200 measured by a free-fall dart drop method using a dart drop impact tester.

[0071] [Table 3]

[0072]

[0073] In the embodiment, the peak force of the dart impact strength is reduced from 44 kgf before autoclave sterilization to 42 kgf after autoclave sterilization, and the change rate of the peak force of the dart impact strength before and after autoclave sterilization is 4%. On the contrary, in the comparative example, the peak force of the dart impact strength is reduced from 41 kgf before autoclave sterilization to 33 kgf after autoclave sterilization, and the change rate of the peak force of the dart impact strength before and after autoclave sterilization is 21%.

[0074] Therefore, it can be seen that the film laminate 100 and the packaging material 200 of the example have an optimized configuration for a cooking or transportation process because the change rate of the dart impact strength before and after autoclave sterilization is much smaller than that of the comparative example.

[0075] While the invention has been described in conjunction with what are presently considered to be practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0076] (Explanation of Reference Numerals)

[0077] 11: First OPP film 12: Second OPP film

[0078] 21: First CPP film 22: Second CPP film

[0079] 100: Film laminate 110: First film laminate

[0080] 120: Second film laminating material 200,400: Packaging material

[0081] 300: Sealing part 410: Upper area

[0082] 411: upper end 420: lower area

[0083] 421: Lower DL: Dry laminate layer

Claims

1. A kettle type sterilization film laminate material, comprising: a first OPP film formed of oriented polypropylene (OPP); a first CPP film formed of cast polypropylene (CPP) and laminated on one surface of the first OPP film; a second OPP film formed of oriented polypropylene and laminated on one surface of the first CPP film; and A second CPP film is formed of cast polypropylene and is laminated on one surface of the second OPP film.

2. The autoclave-type sterilized film laminate according to claim 1, wherein: At least one of the first OPP film and the second OPP film is formed as a barrier-type OPP film that blocks oxygen or moisture.

3. The autoclave-type sterilized film laminate according to claim 2, wherein: The barrier type OPP film is formed as a transparent film on which AlOx is deposited.

4. The autoclave-type sterilized film laminate according to claim 2, wherein: The barrier type OPP film is formed as a transparent film on which a SiOx type inorganic material is deposited.

5. The autoclave-sterilized film laminate according to claim 1, wherein: The first CPP film has surface irregularities by performing corona treatment on both surfaces.

6. The autoclave-sterilized film laminate according to claim 1, wherein: The first CPP film and the second CPP film have a thickness ratio of 1:1 to 1:2.

5.

7. The autoclave-sterilized film laminate according to claim 1, wherein: The first CPP film and the second CPP film contain a rubber component.

8. The autoclave-sterilized film laminate according to claim 1, wherein: A dry laminate layer is provided between each of the first OPP film, the first CPP film, the second OPP film, and the second CPP film.

9. A packaging material comprising the autoclave-type sterilized film laminate according to any one of claims 1 to 8, the packaging material comprising: a first film laminate forming one side in the thickness direction of the packaging material; a second film laminate forming the other side in the thickness direction of the packaging material; and a sealing portion forming the periphery of the first film laminate and the second film laminate, wherein The sealing portions are bonded by the second CPP films facing each other.

10. The packaging material according to claim 9, wherein: The thickness of the second CPP film in the sealing portion is formed to be greater than the thickness of the first CPP film disposed between the first OPP film and the second OPP film.

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