Highly transparent, high-toughness, antistatic polypropylene composite film and its preparation process

Abstract

The application belongs to the technical field of packaging, and particularly relates to a high-transparency, high-tenacity and high-antistatic polypropylene composite film and a preparation process thereof. The composite film is composed of a BOPP printing film and a CPP film; the CPP film is sequentially provided with a heat-sealing layer, an intermediate layer and a corona layer from inside to outside; the corona layer is connected with the printing surface of the BOPP printing film; the corona layer is composed of 100 parts by mass of binary copolymerized polypropylene; the intermediate layer is composed of 80-90 parts by mass of homopolymerized polypropylene and 10-20 parts by mass of a three-block copolymer; and the heat-sealing layer is composed of 90-95 parts by mass of ternary copolymerized polypropylene, 4-6 parts by mass of an antistatic agent and 2-4 parts by mass of an opening agent. The application has excellent antistatic effect, does not absorb and clamp powder during the packaging process, has high transparency, good shelf display effect, high tenacity, good sealing property and no package breakage.

Description

TECHNICAL FIELD

[0001] The present application relates to the packaging technical field, and particularly to a high-transparency, anti-static and high-toughness polypropylene composite film and a preparation process thereof. BACKGROUND

[0002] The food soft packaging industry originated in Europe and the United States in the early 20th century. In the early 1950s, with the advent of plastic packaging materials, the food soft packaging industry has developed rapidly. In the 1970s, the soft packaging industry entered a mature stage and began to appear multi-layer composite packaging materials. In the 1980s, with the wide application of high-tech materials, the food soft packaging industry entered a period of rapid development.

[0003] Food soft packaging is a component of food commodities. Food packaging and food packaging boxes protect food, prevent biological, chemical and physical external factors from damaging food during the process of leaving the factory to the consumer, and also have the function of maintaining the stable quality of food itself, which facilitates the use of food and is the first to show the appearance of food, attract the image of consumption, and have a value beyond the cost of materials.

[0004] There is a special food powder packaging in the food soft packaging, mainly packaging milk powder, flour, purple potato powder, seasoning powder, curry powder, seasoning powder, food additives and other powder materials. The powder food packaging mainly uses a vertical packaging machine. The vertical packaging machine feeds through the material stretching feeding device during the packaging process. The plastic film forms a cylindrical shape through the film cylinder. The side is sealed through the hot longitudinal sealing device. The horizontal sealing mechanism cuts the packaging length and position according to the color mark photoelectric detection device. The powder is light in quality and small in particle size, and is easy to float in the air and be attracted by static electricity. Due to the characteristics of food powder, the packaging has a more special requirement than other food packaging, that is, the film has anti-static property. Otherwise, it is easy to be attracted by static electricity, resulting in powder clamping. Powder clamping not only affects the appearance, but also affects the sealing of the packaging, resulting in air leakage, which causes the contents to deteriorate. For some transparent powder packaging, consumers can see the contents. The low transparency and high haze reduce the product display effect. If the powder packaging has a certain toughness, it is easy to break and cause leakage.

[0005] The transparent packaging material of the food powder on the market at present is BOPP / CPP, PET / CPP and PET / PE. The main disadvantages are low transparency, poor shelf display effect, and static film. During the packaging process, the powder is easy to be attracted by the sealing and clamping, which further leads to poor packaging effect and easy air leakage, and low toughness is easy to break the package. Therefore, a high-transparency, anti-static and high-toughness polypropylene composite film and a preparation process thereof are needed to solve the above problems. SUMMARY

[0006] To solve the above technical problems, the present application provides a high-transparency, high-toughness, and high-antistatic polypropylene composite film and a preparation process thereof.

[0007] To achieve one of the purposes of the present application, the present application adopts the following technical solutions:

[0008] A high-transparency, high-toughness, and high-antistatic polypropylene composite film, which is composed of a BOPP printing film and a CPP film; the CPP film is sequentially provided with a heat-sealing layer, an intermediate layer, and a corona layer from inside to outside; the corona layer is connected with the printing surface of the BOPP printing film; the corona layer is composed of 100 parts by mass of binary copolymerized polypropylene; the intermediate layer is composed of 80-90 parts by mass of homopolymerized polypropylene and 10-20 parts by mass of a triblock copolymer; and the heat-sealing layer is composed of 90-95 parts by mass of ternary copolymerized polypropylene, 3-6 parts by mass of an antistatic agent, and 2-4 parts by mass of an opening agent.

[0009] Preferably, the intermediate layer is composed of 85 parts by mass of homopolymerized polypropylene and 15 parts by mass of a triblock copolymer; and the heat-sealing layer is composed of 92 parts by mass of ternary copolymerized polypropylene, 5 parts by mass of an antistatic agent, and 3 parts by mass of an opening agent.

[0010] Preferably, the thickness ratio of the corona layer, the intermediate layer, and the heat-sealing layer is 3:11:6.

[0011] Preferably, the binary copolymerized polypropylene is W331 produced by TPC Company; the homopolymerized polypropylene is HA849K produced by LyondellBasell Company in the Netherlands; the triblock copolymer is G1657M produced by Kraton Company in the United States; the ternary copolymerized polypropylene is C5908M produced by Yanshan Petrochemical Company; the antistatic agent is P-2800HC produced by Zhu Ben Grease Company; and the opening agent is TC003F produced by Zhejiang Weikai.

[0012] Preferably, the composite film is composed of the BOPP printing film and the CPP film through solvent-free compounding.

[0013] To achieve the second purpose of the present application, the present application provides a preparation process of a high-transparency, high-toughness, and high-antistatic polypropylene composite film, which includes the following steps:

[0014] S1, preparing a BOPP printing film by gravure printing a BOPP film;

[0015] S2, respectively taking components of each mass fraction according to the formula composition of the heat-sealing layer, the intermediate layer, and the corona layer of the CPP film, and preparing a CPP film through casting processing.

[0016] S3. The obtained BOPP printed film and CPP film are solvent-free laminated to obtain a polypropylene composite film.

[0017] Preferably, in step S2, the CPP film undergoes high-voltage online corona treatment during the casting process to achieve a surface chromium value of 38 or higher.

[0018] Preferably, in step S3, the adhesive used for solvent-free lamination is a mixture of the main agent and the curing agent in a mass ratio of 100:60. The main agent is Henkel Adhesive 7728 and the curing agent is Henkel 6028.

[0019] Preferably, the amount of adhesive applied is 1.5 g / m³. 2 .

[0020] Preferably, in step S3, after the BOPP printed film and CPP film are solvent-free laminated, they are cured at room temperature for 36 hours.

[0021] The advantages of this invention compared to the prior art are as follows:

[0022] 1) This invention has excellent antistatic effect, does not absorb or trap powder during packaging; has high transparency, good shelf display effect; has high toughness, good sealing performance, and does not break the package.

[0023] 2) Corona layer: The binary copolymer polypropylene with grade W331 is used. It does not contain slip agents or opening agents, has good processing adaptability, stable surface tension after corona treatment, high peel strength after lamination, and good transparency.

[0024] 3) Intermediate layer: The addition of homopolymer polypropylene resin of grade HA849K has very high clarity, extremely high transparency, low odor and taste transmission, and good heat resistance. At the same time, the triblock copolymer of grade G1657M is a transparent linear triblock copolymer of styrene, ethylene and butene. Co-extrusion with polypropylene can greatly improve the toughness of the roll film.

[0025] 4) Heat-sealing layer: The ternary copolymer polypropylene with grade C5908M has a low crystallization temperature, high heat-sealing strength, low heat-sealing initiation temperature (100-115℃), good resistance to boiling, good low-temperature impact resistance, and high transparency and good processing adaptability. The erucamide antistatic agent with grade P-2800HC can make the surface resistance ρ of the film about 10^8Ω, which greatly reduces the electrostatic accumulation effect of the film. The opening agent with grade TC003F makes the film have better opening properties.

[0026] 5) The food powder packaging roll film developed in this invention has extremely high transparency, which can well display the contents of the product packaging, allowing consumers to see the contents of the packaging better. It also has good anti-static effect, and the anti-static effect is more durable and stable. It does not absorb or trap powder during machine packaging, and the packaging effect is good. At the same time, it has high toughness, good packaging size stability, and is not easy to break. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] A highly transparent, antistatic, and high-toughness polypropylene composite film is disclosed, comprising a BOPP printed film and a CPP film. The CPP film, from the inside out, consists of a heat-sealing layer, an intermediate layer, and a corona layer. The corona layer is connected to the printed surface of the BOPP printed film. The corona layer is composed of 100 parts by weight of binary copolymer polypropylene. The intermediate layer is composed of 80-90 parts by weight of homopolymer polypropylene and 10-20 parts by weight of triblock copolymer. The heat-sealing layer is composed of 90-95 parts by weight of ternary copolymer polypropylene, 3-6 parts by weight of antistatic agent, and 2-4 parts by weight of opening agent. The thickness ratio of the corona layer, intermediate layer, and heat-sealing layer is 3:11:6. The grade of binary copolymer polypropylene is W331 produced by TPC; the grade of homopolymer polypropylene is HA849K produced by LyondellBasell, Netherlands; the grade of triblock copolymer is G1657M produced by Kraton, USA; the grade of ternary copolymer polypropylene is C5908M produced by Yanshan Petrochemical Company; the grade of antistatic agent is P-2800HC produced by Takemoto Oils & Fats Co., Ltd.; the grade of opening agent is TC003F from Zhejiang Weikai. All particle grades in Examples 1-3 below are the same. The grade of BOPP printing film is not limited.

[0030] A process for preparing a highly transparent, antistatic, and high-toughness polypropylene composite film includes the following steps:

[0031] S1. BOPP printed film is obtained by gravure printing of BOPP film.

[0032] S2. According to the formulation of the heat-sealing layer, intermediate layer and corona layer of CPP film, weigh each component by mass and perform casting process to obtain CPP film.

[0033] S3. The obtained BOPP printed film and CPP film are solvent-free laminated to obtain a polypropylene composite film.

[0034] In step S2, the CPP film undergoes high-voltage online corona treatment during the casting process to achieve a surface chroma value of 38 or higher. In step S3, the solvent-free laminating adhesive is a mixture of the main agent and the curing agent at a mass ratio of 100:60. The main agent is Henkel Adhesive 7728, and the curing agent is Henkel 6028. The adhesive application rate is 1.5 g / m³. 2 In step S3, the BOPP printed film and CPP film are solvent-free laminated and then cured at room temperature for 36 hours.

[0035] Example 1

[0036] In the prepared polypropylene composite film 1, the corona layer of the CPP film consists of 100 parts by mass of binary copolymer polypropylene; the intermediate layer consists of 80 parts by mass of homopolymer polypropylene and 20 parts by mass of triblock copolymer; and the heat-sealing layer consists of 90 parts by mass of ternary copolymer polypropylene, 6 parts by mass of antistatic agent, and 4 parts by mass of opening agent. The preparation method is as described above, and the initial heat-sealing temperature is 100°C.

[0037] Example 2

[0038] In the prepared polypropylene composite film 2, the corona layer of the CPP film consists of 100 parts by mass of binary copolymer polypropylene; the intermediate layer consists of 85 parts by mass of homopolymer polypropylene and 15 parts by mass of triblock copolymer; the heat-sealing layer consists of 92 parts by mass of ternary copolymer polypropylene, 5 parts by mass of antistatic agent, and 3 parts by mass of opening agent. The preparation method is as described above, and the initial heat-sealing temperature is 110℃.

[0039] Example 3

[0040] In the prepared polypropylene composite film 3, the corona layer of the CPP film consists of 100 parts by mass of binary copolymer polypropylene; the intermediate layer consists of 90 parts by mass of homopolymer polypropylene and 10 parts by mass of triblock copolymer; and the heat-sealing layer consists of 95 parts by mass of ternary copolymer polypropylene, 3 parts by mass of antistatic agent, and 2 parts by mass of opening agent. The preparation method is as described above, and the initial heat-sealing temperature is 115℃.

[0041] Comparative Example 1

[0042] The corona layer of the CPP film consists of 100 parts by weight of a first polypropylene, the intermediate layer consists of 90 parts by weight of polypropylene and 10 parts by weight of random copolymer polypropylene, and the heat-sealing layer consists of 96 parts by weight of polyolefin and 4 parts by weight of opening agent. The CPP film is then laminated with a BOPP printing film according to the preparation process of this invention to obtain a composite film.

[0043] The first polypropylene is FCP80 produced by Sino-Korean (Wuhan) Petrochemical Company; the random copolymer polypropylene is RD265CF produced by Borouge Chemical Company; the polyolefin is FL7642 produced by Singapore Polyolefin Company; and the opening agent is ABPP10S produced by Polylide Company.

[0044] The performance of the polypropylene composite film 2 prepared in Example 2 and the composite film of Comparative Example 1 were tested, and the results are shown in Table 1 below:

[0045] Table 1

[0046]

[0047] As shown in Table 1, the haze in the composite film prepared in Example 2 is much smaller than that in the composite film prepared in Comparative Example 1. Therefore, the composite film prepared by the present invention has high transparency. Furthermore, the resistance of the composite film in Comparative Example 1 exceeds 10^12 Ω, indicating no antistatic effect and static electricity accumulation, which can easily lead to powder trapping and air leakage at the sealing point. The resistance of the composite film prepared in Example 2 is ≤10^8 Ω, indicating a good antistatic effect. The tensile strength of the composite film prepared in Example 2 is better than that of the composite film prepared in Comparative Example 1, indicating that the composite film of the present invention has high toughness.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A highly transparent, antistatic, and high-toughness polypropylene composite film, characterized in that, This composite film is made of BOPP printed film and CPP film. The CPP film has a heat-sealing layer, an intermediate layer, and a corona layer arranged sequentially from the inside out. The corona layer is connected to the printed surface of the BOPP printed film. The corona layer consists of 100 parts by weight of binary copolymer polypropylene. The intermediate layer consists of 85 parts by weight of homopolymer polypropylene and 15 parts by weight of triblock copolymer. The heat-sealing layer consists of 92 parts by weight of ternary copolymer polypropylene, 5 parts by weight of antistatic agent, and 3 parts by weight of opening agent. The grade of the binary copolymer polypropylene is W331 produced by TPC Corporation. The grade of the homopolymer polypropylene is HA849K produced by LyondellBasell, Netherlands. The grade of the triblock copolymer is G1657M produced by Kraton Pharmaceuticals, USA. The grade of the ternary copolymer polypropylene is C5908M produced by Yanshan Petrochemical Company. The grade of the antistatic agent is P produced by Takemoto Oils Co., Ltd. 2800HC; the brand of the opening agent is TC003F from Zhejiang Weikai.

2. The highly transparent, antistatic, and high-toughness polypropylene composite film according to claim 1, characterized in that, The thickness ratio of the corona layer intermediate layer to the heat seal layer is 3:11:

6.

3. The highly transparent, antistatic, and high-toughness polypropylene composite film according to claim 1, characterized in that, This composite film is made by solvent-free lamination of BOPP printed film and CPP film.

4. A method as claimed in claim 1 The preparation process of the high-transparency, antistatic, and high-toughness polypropylene composite film according to any one of the following methods is characterized in that, The preparation process includes the following steps: S1. BOPP printed film is obtained by gravure printing of BOPP film. S2. According to the formulation of the heat-sealing layer, intermediate layer and corona layer of CPP film, weigh each component by mass and perform casting process to obtain CPP film. S3. The obtained BOPP printed film and CPP film are solvent-free laminated to obtain a polypropylene composite film.

5. The preparation process of a highly transparent, antistatic, and high-toughness polypropylene composite film according to claim 4, characterized in that, In step S2, the CPP film undergoes high-voltage online corona treatment during the casting process to achieve a surface chromium value of 38 or higher.

6. The preparation process of a highly transparent, antistatic, and highly tough polypropylene composite film according to claim 4, characterized in that, In step S3, the adhesive used for solvent-free lamination is a mixture of the main agent and the curing agent in a mass ratio of 100:

60. The main agent is Henkel Adhesive 7728 and the curing agent is Henkel 6028.

7. The preparation process of a highly transparent, antistatic, and highly tough polypropylene composite film according to claim 6, characterized in that, The amount of adhesive applied is 1.5 g / m. 2 .

8. The preparation process of a highly transparent, antistatic, and high-toughness polypropylene composite film according to claim 4, characterized in that, In step S3, the BOPP printed film and CPP film are solvent-free laminated and then cured at room temperature for 36 hours.

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