Novel environment-friendly high-barrier CPP film and preparation method thereof

Abstract

The invention discloses a novel environment-friendly high-barrier CPP film and a preparation method thereof.The novel environment-friendly high-barrier CPP film comprises a base film layer, a corona layer and a heat sealing layer, the corona layer and the heat sealing layer are arranged on the two sides of the base film layer respectively, the novel environment-friendly high-barrier CPP film further comprises a protective surface layer, and the protective surface layer is arranged on the side, away from the base film layer, of the corona layer; a plurality of color-changing patterns made of thermochromic materials are arranged between the protective surface layer and the corona layer, and the color of the patterns changes after the patterns reach the corresponding temperature. The color-changing patterns made of the thermochromic materials are arranged between the base film layer and the heat sealing layer and can be used for indicating the real-time packaging temperature; when the packaging environment temperature is higher than the color-changing temperature of the color-changing pattern made of the thermochromic material, the color-changing pattern made of the thermochromic material is dominant, a user can judge whether the packaging environment temperature is too high or not by observing whether the color-changing pattern is dominant or not, and it can be conveniently ensured that the packaging and products in the packaging are at the proper temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of CPP films, in particular to a new type of environmentally friendly high-barrier CPP film and its preparation method. Background Art

[0002] With the development of technology, various commodities are increasing day by day. As a packaging material, CPP film is widely used in the packaging of food, medicine, daily necessities and electronic products because of its good isolation effect on water vapor and odor and high transparency. Among them, since food, medicine, etc. have very strict requirements for the storage environment, especially the environmental temperature requirements, once the environmental temperature is too high, it may cause the deterioration and damage of food and medicine. Therefore, it is of great significance to design a CPP film that can indicate the environmental temperature. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems in the prior art, and propose a new type of environmentally friendly high-barrier CPP film and its preparation method. The CPP film is internally provided with a color-changing pattern made of a thermosensitive color-changing material. Users can observe whether the color-changing pattern is visible to judge whether the packaging environmental temperature is too high, which can conveniently ensure that the packaging and the products inside the packaging are at a suitable temperature.

[0004] To achieve the above purpose, the present invention proposes a new type of environmentally friendly high-barrier CPP film, which includes a base film layer, a corona layer, and a heat-sealing layer. The corona layer and the heat-sealing layer are respectively arranged on both sides of the base film layer. It also includes a protective surface layer, which is arranged on the side of the corona layer away from the base film layer. There are several color-changing patterns made of thermosensitive color-changing materials between the protective surface layer and the corona layer. The patterns change color after reaching the corresponding temperature. The base film layer is composed of homopolypropylene, the heat-sealing layer is composed of copolymerized polypropylene, the corona layer is composed of copolymerized polypropylene, and the protective surface layer is composed of polylactic acid resin.

[0005] Preferably, there are at least two color-changing patterns made of different thermosensitive color-changing materials between the protective surface layer and the corona layer, and each thermosensitive color-changing material changes color at different temperatures.

[0006] Preferably, the thermosensitive color-changing materials include: RZ-T40 produced by Guangzhou Rongzhi Chemical Technology Co., Ltd., with a color-changing temperature of 40°C, showing a colorless state below 40°C and a purple or orange state above 40°C; JH-T65 produced by Shanghai Jiehong New Materials Group, with a color-changing temperature of 65°C, showing a colorless state below 65°C and a yellow state above 65°C; CCC-ThermoClear produced by Color Change Corporation of the United States TM70, the color-changing temperature is 70 °C. When the temperature is lower than 70 °C, it presents a colorless state, and when it is higher than 70 °C, it presents a black state.

[0007] Preferably, the color-changing pattern is configured as numbers or words corresponding to the color-changing temperature value of the thermochromic material.

[0008] Preferably, the thickness ratio of the base film layer to the heat-sealing layer is 6 - 7.5 to 4 - 2.5.

[0009] Preferably, the base film layer further includes an antistatic agent, and according to the weight parts, it is 98 parts of homopolypropylene and 1.5 - 3 parts of the antistatic agent.

[0010] Preferably, the base film layer further includes 3 - 8 parts of modified nano-montmorillonite.

[0011] Preferably, the heat-sealing layer further includes a degradation aid, and according to the weight parts, it is 80 parts of copolymerized polypropylene, 5 - 10 parts of PLA / PP graft copolymer, and 0.5 - 1.5 parts of the degradation aid.

[0012] Another object of the present invention is to propose a preparation method for making the novel environmentally friendly high-barrier CPP film described in any one of the above, including the following steps:

[0013] Step S1, batching, respectively weighing the raw materials of each layer according to the formula of the base film layer, corona layer, and heat-sealing layer;

[0014] Step S2, mixing, mixing the raw materials weighed in step S1 respectively, and the mixing time is more than 5 minutes;

[0015] Step S3, extrusion, respectively feeding the raw materials of the base film layer, corona layer, and heat-sealing layer after mixing in step S2 into their respective extruders for melting, mixing, and plasticizing;

[0016] Step S4, respectively feeding the molten melt into the die head, and after the melts converge in the die head, a molten sheet is formed through the flat die head opening;

[0017] Step S5, using an air knife to attach the sheet to a chill roll and after water bath cooling, shaping the sheet into a film;

[0018] Step S6, corona-treating the corona layer side of the film obtained in step S5 to obtain a corona-treated film;

[0019] Step S7, coating the corona layer side of the film obtained in step S6 with a thermochromic material according to a preset pattern;

[0020] Step S8, introducing the film after coating in step S7 into an oven for drying, and the drying temperature is 80 - 100 °C;

[0021] Step S9: Compound the protective surface layer on the surface of the film dried in Step S8;

[0022] Step S10: Measure the thickness of the film obtained in Step S9 for quality inspection. After passing the inspection, send it to the winding equipment to wind it into a finished film roll.

[0023] Preferably, Step S7 further includes first imprinting a corresponding pattern concave film on the corona layer side of the film obtained in Step S6 through an imprinting device, and coating the thermochromic material in the pattern concave film.

[0024] Beneficial effects of a novel environmentally friendly high-barrier CPP film and its preparation method of the present invention: By setting a color-changing pattern made of a thermochromic material between the base film layer and the heat-sealing layer, the present invention can be used to indicate the real-time temperature of the package. When the temperature of the packaging environment is higher than the color-changing temperature of the color-changing pattern made of the thermochromic material, the color-changing pattern made of the thermochromic material can be visible. Users can observe whether the color-changing pattern is visible to judge whether the temperature of the packaging environment is too high, which can conveniently ensure that the package and the products inside are at an appropriate temperature.

[0025] The features and advantages of the present invention will be described in detail through examples in conjunction with the drawings. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of a novel environmentally friendly high-barrier CPP film of the present invention.

[0027] Figure 2 is a schematic structural diagram of the color-changing pattern of a novel environmentally friendly high-barrier CPP film of the present invention.

[0028] In the figure: 1 - base film layer, 2 - corona layer, 3 - heat-sealing layer, 4 - protective surface layer, 5 - adhesive layer. Detailed Embodiments

[0029] To make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below through the drawings and examples. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concepts of the present invention.

[0030] In the description of the present invention, it should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0031] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this invention is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention. In addition, terms such as "first", "second", "third", etc. are only used for differential description and cannot be understood as indicating or implying relative importance. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more, unless otherwise specifically and clearly defined. The meaning of "several" is one or more, unless otherwise specifically and clearly defined.

[0032] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Embodiment 1:

[0034] Refer to Figure 1 、 Figure 2 For a novel environmentally friendly high-barrier CPP film of the present invention, it includes a protective surface layer 4, a corona layer 2, a base film layer 1, and a heat-sealing layer 3 which are sequentially arranged from top to bottom. Between the protective surface layer 4 and the corona layer 2, there are several color-changing patterns made of thermosensitive color-changing materials, and the patterns change color after reaching the corresponding temperature; wherein, the base film layer 1 is composed of 98 parts of homopolypropylene and 2 parts of antistatic agent; the heat-sealing layer 3 is composed of copolymerized polypropylene, the corona layer 2 is composed of copolymerized polypropylene, and the protective surface layer 4 is composed of polylactic acid resin. In this embodiment, a color-changing pattern made of thermosensitive color-changing materials is arranged between the base film layer 1 and the heat-sealing layer 3, which can be used to indicate the real-time temperature of the package. When the temperature of the packaging environment is higher than the color-changing temperature of the color-changing pattern made of thermosensitive color-changing materials, the color-changing pattern made of thermosensitive color-changing materials can be visible, and users can observe whether the color-changing pattern is visible to judge whether the temperature of the packaging environment is too high, which can conveniently ensure that the package and the product inside the package are at an appropriate temperature.

[0035] Specifically, three color-changing patterns made of different thermochromic materials are provided between the protective surface layer 4 and the corona layer 2. Each of the thermochromic materials changes color at different temperatures, and the colors after thermochromic change of each thermochromic material are different. Multiple thermochromic materials can be used to indicate multiple temperatures respectively, expanding the indication range and facilitating users to master the packaging temperature.

[0036] Specifically, the thermochromic materials include: RZ-T40 produced by Guangzhou Rongzhi Chemical Technology Co., Ltd., with a color-changing temperature of 40 °C, showing a colorless state below 40 °C and a purple or orange state above 40 °C; JH-T65 produced by Shanghai Jiehong New Materials Group, with a color-changing temperature of 65 °C, showing a colorless state below 65 °C and a yellow state above 65 °C; CCC-ThermoClear TM 70 produced by Color Change Corporation of the United States, with a color-changing temperature of 70 °C, showing a colorless state below 70 °C and a black state above 70 °C.

[0037] Specifically, the color-changing pattern is configured as a number corresponding to the color-changing temperature value of the thermochromic material. Among them, the pattern formed by RZ-T40 produced by Rongzhi Chemical Technology Co., Ltd. is the text of 40 °C corresponding to its color-developing temperature, the pattern formed by JH-T65 produced by Shanghai Jiehong New Materials Group is the text of 65 °C corresponding to its color-developing temperature, and the pattern formed by CCC-ThermoClear TM 70 produced by Color Change Corporation of the United States is the text of 70 °C corresponding to its color-developing temperature.

[0038] Specifically, the thickness ratio of the base film layer 1 to the heat-sealing layer 3 is 7 to 3.

[0039] Specifically, the protective surface layer 4 and the corona layer 2 are connected through an adhesive layer 5.

[0040] Embodiment 2:

[0041] Refer to Figure 1, in this embodiment, the new environmentally friendly high-barrier CPP film includes a protective surface layer 4, a corona layer 2, a base film layer 1, and a heat-sealing layer 3 arranged in sequence from top to bottom. Between the protective surface layer 4 and the corona layer 2, there are several color-changing patterns made of thermochromic materials, and the patterns change color when reaching the corresponding temperature. Among them, the base film layer 1 is composed of 98 parts of homopolypropylene, 2 parts of antistatic agent, and 5 parts of modified nano-montmorillonite, and the nano-montmorillonite is treated by plasma. The heat-sealing layer 3 is composed of copolymerized polypropylene, the corona layer 2 is composed of copolymerized polypropylene, and the protective surface layer 4 is composed of polylactic acid resin. In this embodiment, modified nano-montmorillonite is added to the base film layer 1, and the barrier property of the film is improved by using nano-montmorillonite, so that it can meet the long-term storage requirements of high-fat foods or easily oxidized drugs.

[0042] Specifically, the nano-montmorillonite is treated in argon plasma for 10 minutes with a power of 300W to increase the surface hydroxyl density.

[0043] Embodiment Three:

[0044] Refer to Figure 1 , in this embodiment, the new environmentally friendly high-barrier CPP film includes a protective surface layer 4, a corona layer 2, a base film layer 1, and a heat-sealing layer 3 arranged in sequence from top to bottom. Between the protective surface layer 4 and the corona layer 2, there are several color-changing patterns made of thermochromic materials, and the patterns change color when reaching the corresponding temperature. Among them, the base film layer 1 is composed of 98 parts of homopolypropylene and 2 parts of antistatic agent; the heat-sealing layer 3 is composed of 80 parts of copolymerized polypropylene, 8 parts of PLA / PP graft copolymer, and 1 part of degradation aid. The corona layer 2 is composed of copolymerized polypropylene, and the protective surface layer 4 is composed of polylactic acid resin. The degradation aid is a transition metal stearate, such as iron stearate. In this embodiment, modified nano-montmorillonite is added to the base film layer 1, and the barrier property of the film is improved by using nano-montmorillonite, so that it can meet the long-term storage requirements of high-fat foods or easily oxidized drugs.

[0045] Comparative Example:

[0046] In this embodiment, the film includes a corona layer 2, a base film layer 1, and a heat-sealing layer 3 arranged in sequence from top to bottom. The base film layer 1 is composed of homopolypropylene; the heat-sealing layer 3 is composed of copolymerized polypropylene, the corona layer 2 is composed of copolymerized polypropylene, and the protective surface layer 4 is composed of polylactic acid resin.

[0047] The films prepared in Example One, Example Two, Example Three, and the Comparative Example are tested, including oxygen transmission rate (OTR) test and degradation rate test. Among them, the OTR test is carried out in accordance with the ASTM D3985 standard, and the degradation rate test is carried out in accordance with the provisions of ASTM D5338-92. The measured results are as follows in the table:

[0048]

[0049] As can be seen from the above table, the OTR test result of the film in Example 2 with added nano-montmorillonite is the best. The barrier property of the film in Example 2 with added nano-montmorillonite is significantly improved compared with other films without added nano-montmorillonite, and the degradation rate of Example 3 with added PLA / PP graft copolymer and degradation aid is significantly increased.

[0050] Example 4:

[0051] This example presents a preparation method for the novel environmentally friendly high-barrier CPP film in the above examples, including the following steps:

[0052] Step S1, ingredient preparation, respectively weigh the raw materials of the base film layer, corona layer, and heat-sealing layer according to their respective formulas;

[0053] Step S2, mixing, mix the raw materials weighed in Step S1 respectively, and the mixing time is more than 5 minutes;

[0054] Step S3, extrusion, send the raw materials of the base film layer, corona layer, and heat-sealing layer after mixing in Step S2 into their respective extruders for melting, mixing, and plasticizing;

[0055] Step S4, respectively send the molten melt into the die head. After the melts converge in the die head, a molten sheet is formed through the flat die head opening;

[0056] Step S5, use an air knife to attach the sheet to the chill roll and, after water bath cooling, shape the sheet into a film;

[0057] Step S6, perform corona treatment on the corona layer side of the film obtained in Step S5 to obtain the corona-treated film;

[0058] Step S7, first use an embossing device to emboss a corresponding pattern recessed film on the corona layer side of the film obtained in Step S6, and coat the thermochromic material in the pattern recessed film; Setting the recessed film can improve the pattern adhesion and the pattern forming effect;

[0059] Step S8, introduce the film after coating in Step S7 into an oven for drying, and the drying temperature is 80 - 100 °C;

[0060] Step S9, laminate the protective surface layer on the surface of the film dried in Step S8;

[0061] Step S10, perform thickness measurement and quality inspection on the film prepared in Step S9. After passing the inspection, send it to a winding device to wind it into a finished film roll. The preparation method of this example can coat a pattern composed of a thermochromic material on the surface of the film after casting and laminate a protective surface layer for protection, enabling the film to have thermochromic properties and improving its functionality.

[0062] It should be noted that although the above embodiments have been described in this text, it does not limit the patent protection scope of the present invention. Therefore, based on the innovative concept of the present invention, any changes and modifications made to the embodiments described in this text, or equivalent structural or equivalent process transformations made by using the content of the specification and drawings of the present invention, and directly or indirectly applying the above technical solutions to other related technical fields, are all included within the protection scope of the patent of the present invention.

Claims

1. A new type of environmentally friendly high-barrier CPP film, comprising a base film layer (1), a corona layer (2), and a heat-sealing layer (3). The corona layer (2) and the heat-sealing layer (3) are respectively disposed on both sides of the base film layer (1), and it is characterized in that: It further includes a protective surface layer (4), the protective surface layer (4) is disposed on the side of the corona layer (2) away from the base film layer (1), and a plurality of color-changing patterns made of thermosensitive color-changing materials are provided between the protective surface layer (4) and the corona layer (2), and the patterns change color after reaching the corresponding temperature. The base film layer (1) is composed of homopolypropylene, the heat-sealing layer (3) is composed of copolymerized polypropylene, the corona layer (2) is composed of copolymerized polypropylene, and the protective surface layer (4) is composed of polylactic acid resin.

2. The novel environmentally friendly high-barrier CPP film according to claim 1, wherein: At least two color-changing patterns made of different thermosensitive color-changing materials are provided between the protective surface layer (4) and the corona layer (2), and each of the thermosensitive color-changing materials changes color at different temperatures, and the colors changed by each of the thermosensitive color-changing materials are different after thermosensitive color change.

3. The novel environmentally friendly high-barrier CPP film according to claim 1, characterized in that: The color-changing pattern is configured as a number or text corresponding to the color-changing temperature value of the thermosensitive color-changing material.

4. The novel environmentally friendly high-barrier CPP film according to claim 1, wherein: The thickness ratio of the base film layer (1) to the heat-sealing layer (3) is 6 - 7.5 to 4 - 2.

5.

5. The novel environmentally friendly high-barrier CPP film according to claim 1, wherein: The base film layer (1) further includes an antistatic agent, and by weight, it is 98 parts of homopolypropylene and 1.5 - 3 parts of antistatic agent.

6. The novel environmentally friendly high-barrier CPP film according to claim 5, characterized in that: The base film layer (1) further includes 3 - 8 parts of modified nano-montmorillonite.

7. The novel environmentally friendly high-barrier CPP film according to claim 1, wherein: The heat-sealing layer (3) further includes a degradation aid, and by weight, it is 80 parts of copolymerized polypropylene, 5 - 10 parts of PLA / PP graft copolymer, and 0.5 - 1.5 parts of degradation aid.

8. A preparation method for the novel environmentally friendly high-barrier CPP film according to any one of claims 1-7, characterized in that, It includes the following steps: Step S1, ingredient preparation, respectively weigh the respective raw materials according to the formulations of the base film layer, corona layer, and heat-sealing layer; Step S2, mixing, mix the raw materials weighed in Step S1 respectively, and the mixing time is 5 minutes or more; Step S3, extrusion, respectively feed the raw materials of the base film layer, corona layer, and heat-sealing layer after mixing in Step S2 into their respective extruders for melt mixing and plasticization; Step S4, respectively feed the molten melt into the die head, and after the melts converge in the die head, form a molten sheet through the flat die head opening; Step S5, use an air knife to attach the sheet to a chill roll and after water bath cooling, shape the sheet to form a film; Step S6, perform corona treatment on the corona layer side of the film obtained in Step S5 to obtain a corona-treated film; Step S7, coat the corona layer side of the film obtained in Step S6 with a thermosensitive color-changing material according to a preset pattern; Step S8, introduce the film after coating in Step S7 into an oven for drying, and the drying temperature is 80 - 100 °C; Step S9, laminate the protective surface layer on the surface of the film dried in Step S8; Step S10, perform thickness measurement and quality inspection on the film prepared in Step S9, and after passing the inspection, send it to a winding device to wind it into a finished film roll.

9. The novel environmentally friendly high-barrier CPP film according to claim 8, wherein: Step S7 further includes first imprinting a corresponding pattern concave film on the corona layer side of the film obtained in Step S6 through an imprinting device, and the thermosensitive color-changing material is coated in the pattern concave film.

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