A high-strength easy-to-peel barrier cover film for large cups and its preparation process

Abstract

The present invention belongs to the technical field of packaging materials, in particular to a high-strength easy-to-peel barrier cover film for large cups and its preparation process. The present invention includes an outer layer, a barrier layer and an extruded layer connected in sequence; the outer layer is made of BOPA material, the barrier layer includes a corona layer, an intermediate layer and an inner layer arranged in sequence, the corona layer is connected to the outer layer, and the inner layer is connected to the extruded layer; the corona layer is composed of 100 parts by mass of a first low-density polyethylene, the intermediate layer is composed of 80 parts by mass of a first low-density polyethylene and 20 parts by mass of ethylene-vinyl alcohol copolymer, and the inner layer is composed of 50 parts by mass of a second low-density polyethylene and 25 parts by mass of metallocene polyethylene; the extruded layer is made of ethylene-vinyl acetate copolymer. The present invention has high heat sealing strength and can resist the destructive force of the bulging package; it meets the easy-to-peel characteristics of the cover film, and the cover film can be opened smoothly when it is peeled off, and the cover film has certain barrier properties.

Description

Technical Field

[0001] The invention relates to the technical field of packaging materials, in particular to a high-strength easy-to-peel barrier cover film used for a large cup body and a preparation process thereof. Background Art

[0002] my country is the world's largest producer of jelly and also the largest seller. Various crystal clear jelly products have become an important component of the snack food industry, especially popular among children. As R&D personnel of a flexible packaging manufacturer, we are naturally concerned about the quality of its packaging. Due to the defects in the properties of existing jelly covers, especially the 200g large cup jelly cover, consumers often encounter the following problems when eating jelly. First, children often cannot tear open the jelly cover without the help of adults, and it is not easy to open, which leads to a decrease in the desire to buy jelly. Second, when opening the cover, due to uneven peeling force, the liquid in the jelly is easy to splash out, causing clothes to get dirty. Third, the cover is easy to delaminate when peeled off, and part of the cover remains on the cup body, affecting the consumption of the product.

[0003] In addition, the market now basically has small cups with smaller bodies and smaller contents, and the required cover film does not require high sealing strength. However, large cups are different from small cups. The required cover film has a larger contact area with the cup body and high strength requirements. At the same time, it must meet the easy-to-peel feature of the cover film, which is actually a contradictory relationship. Therefore, there is an urgent need for a large cup jelly cover film packaging material that is easy to peel and has uniform peeling force. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a high-strength easy-to-peel barrier cover film for a large cup body and a preparation process thereof. The material can not only meet the needs of children to eat a large cup of jelly alone, but also has uniform peeling force, is not easy to delaminate, and avoids the influence of residual substances on the quality of the jelly.

[0005] In order to achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0006] A high-strength easy-to-peel barrier cover film for large cups, comprising an outer layer, a barrier layer and an extruded layer connected in sequence; the outer layer is made of BOPA material, the barrier layer comprises a corona layer, an intermediate layer and an inner layer arranged in sequence, the corona layer is connected to the outer layer, and the inner layer is connected to the extruded layer; the corona layer is composed of 100 parts by mass of a first low-density polyethylene, the intermediate layer is composed of 80 parts by mass of the first low-density polyethylene and 20 parts by mass of ethylene-vinyl alcohol copolymer, the inner layer is composed of 50 parts by mass of a second low-density polyethylene and 25 parts by mass of metallocene polyethylene; the extruded layer is made of ethylene-vinyl acetate copolymer.

[0007] Preferably, the brand of the first low-density polyethylene is 2420H produced by BASF-YPC, the brand of the ethylene-vinyl alcohol copolymer is ET3203FB produced by Synthetic Chemical Co., Ltd. of Japan, the brand of the second low-density polyethylene is LD100AC produced by Yanshan Petrochemical Company, the brand of the metallocene polyethylene is SP0510 produced by Primen Co., Ltd. of Japan; and the brand of the ethylene-vinyl acetate copolymer is 53007 produced by DuPont of the United States.

[0008] Preferably, the thickness ratio of the outer layer, the barrier layer and the extruded layer is 3:11:7.

[0009] Preferably, the thickness ratio of the corona layer, the intermediate layer and the heat-sealing layer is 2:7:2.

[0010] The second object of the present invention is to provide a preparation process for a high-strength easy-to-peel barrier cover film for a large cup body, the production process comprising the following steps:

[0011] S1. Add corona layer resin raw materials, middle layer resin raw materials and inner layer resin raw materials into three barrels of a film blowing machine according to the resin raw material formula; blow the raw materials in the three barrels and then cool them to shape them, and then perform corona treatment on the surface of the corona layer of the shaped film to obtain a barrier layer;

[0012] S2, printing the outer layer to obtain an outer layer printed film;

[0013] S3, the barrier layer and the outer printed film are dry-laminated and cured, and then extruded with the extrusion layer, and then cooled and cut in sequence to obtain the cover film.

[0014] Preferably, the glue amount of the dry compound in step S3 is 3.4-3.8 g / m 3 , the composite speed is 100±10m / min; the aging temperature is 55℃, and the aging time is 72h.

[0015] Preferably, in the extrusion process in step S3, the extrusion temperature of the extruder is 235-245°C, the die processing temperature of the extruder is 235-245°C, and the casting roll processing temperature of the extruder is 20±3°C.

[0016] Preferably, cooling means placing the composite film for 24 hours after the extrusion process is completed, and then cutting the composite film after it is completely cooled to obtain the cover film.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The cover film of the present invention has high heat sealing strength and can resist the destructive force of the bulging package; and the cover film can be opened smoothly when peeling off the cover film, and the barrier performance also meets the requirements, which is suitable for the requirements of large cups for high-strength and easy-to-peel cover films; the present invention successfully solves the problem that large cups are prone to leakage, and does not affect the easy-to-peel performance of the cover film. The use of the intermediate material EVOH makes the cover film have good barrier properties.

[0019] 2) The outer layer of the present invention is made of BOPA (nylon) material, which can improve the overall tensile properties and strength of the cover film; the EVA (ethylene-vinyl acetate copolymer) used in the extruded layer has high strength and easy-to-peel properties.

[0020] 3) The first low-density polyethylene (brand 2420H produced by BASF-YPC Co., Ltd.) added to the barrier layer of the present invention has good bonding with BOPA (nylon) and high interlayer peeling strength (peeling strength ≥ 5 (N / 15mm)); adding barrier processing resin ethylene-vinyl alcohol copolymer (brand ET3203FB produced by Japan Synthetic Chemical Co., Ltd.) can improve the barrier properties of the overall cover film; adding 25% of metallocene polyethylene (brand SP05100 produced by Japan Prime Co., Ltd.) improves the peeling strength with the extruded layer. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0022] A high-strength easy-to-peel barrier cover film used for large cups comprises an outer layer, a barrier layer and an extruded layer which are connected in sequence; the outer layer is made of BOPA material, the barrier layer comprises a corona layer, an intermediate layer and an inner layer which are arranged in sequence, the corona layer is connected to the outer layer, and the inner layer is connected to the extruded layer; the corona layer is composed of 100 parts by mass of a first low-density polyethylene, the intermediate layer is composed of 80 parts by mass of the first low-density polyethylene and 20 parts by mass of ethylene-vinyl alcohol copolymer, the inner layer is composed of 50 parts by mass of a second low-density polyethylene and 25 parts by mass of metallocene polyethylene; the extruded layer is made of ethylene-vinyl acetate copolymer.

[0023] The first low-density polyethylene is 2420H produced by BASF-YPC, the ethylene-vinyl alcohol copolymer is ET3203FB produced by Synthetic Chemical Co., Ltd. of Japan, the second low-density polyethylene is LD100AC produced by Yanshan Petrochemical Co., Ltd., the metallocene polyethylene is SP0510 produced by Primen Co., Ltd. of Japan, and the ethylene-vinyl acetate copolymer is 53007 produced by DuPont of the United States. The thickness ratio of the outer layer, barrier layer and extruded layer is 3:11:7. The thickness ratio of the corona layer, the middle layer and the heat-sealing layer is 2:7:2.

[0024] A preparation process for a high-strength easy-to-peel barrier cover film for a large cup body, the production process comprising the following steps:

[0025] S1. Add corona layer resin raw materials, middle layer resin raw materials and inner layer resin raw materials into three barrels of a film blowing machine according to the resin raw material formula; blow the raw materials in the three barrels and then cool them to shape them, and then perform corona treatment on the surface of the corona layer of the shaped film to obtain a barrier layer;

[0026] S2, printing the outer layer to obtain an outer layer printed film;

[0027] S3, the barrier layer and the outer printed film are dry-laminated and cured, and then extruded with the extrusion layer, and then cooled and cut in sequence to obtain the cover film.

[0028] The glue amount of the dry compound in step S3 is 3.4-3.8 g / m 3 , the compounding speed is 100±10m / min; the aging temperature is 55℃, and the aging time is 72h. In the extrusion process in step S3, the extrusion temperature of the extruder is 235-245℃, the die processing temperature of the extruder is 235-245℃, and the casting roll processing temperature of the extruder is 20±3℃. Cooling means that the composite film is placed for 24h after the extrusion process is completed, and the composite film is cut after it is completely cooled to obtain a cover film.

[0029] Example 1

[0030] S1, weighing resin raw materials (the formula is: the corona layer includes 100 parts by mass of the first low-density polyethylene, the middle layer includes 80 parts by mass of the first low-density polyethylene and 20 parts by mass of ethylene-vinyl alcohol copolymer, and the inner layer includes 50 parts by mass of the second low-density polyethylene and 25 parts by mass of metallocene polyethylene), respectively adding the corona layer resin raw material, the middle layer resin raw material and the inner layer resin raw material to the three barrels of the extruder; after the raw materials in the three barrels are co-extruded, they enter the casting station for cooling and shaping, and then the surface of the corona layer of the film after the casting shaping is corona treated to obtain a barrier layer;

[0031] S2, printing the outer layer to obtain an outer layer printed film;

[0032] S3, dry-compounding and aging the barrier layer and the outer printed film, and then subjecting them to an extrusion lamination process with the extrusion lamination layer, followed by cooling and slitting in sequence to obtain the cover film 1.

[0033] Among them, the brand of the first low-density polyethylene is 2420H produced by BASF-YPC, the brand of ethylene-vinyl alcohol copolymer is ET3203FB produced by Japan Synthetic Chemical Co., Ltd., the brand of the second low-density polyethylene is LD100AC produced by Yanshan Petrochemical Co., Ltd., and the brand of metallocene polyethylene is SP0510 produced by Japan Primen Co.; the extruded layer uses ethylene-vinyl acetate copolymer, brand 53007 produced by DuPont of the United States; the thickness of the outer layer, barrier layer and outer layer of the cover film 1 are 15μm, 55μm and 35μm respectively, and the thickness after adding EVOH (ethylene-vinyl alcohol copolymer) is 6-9um.

[0034] Comparative Example 1

[0035] S1, weighing resin raw materials (the formula is: the corona layer includes 100 parts by mass of the first low-density polyethylene, the middle layer includes 80 parts by mass of the first low-density polyethylene and 20 parts by mass of ethylene-vinyl alcohol copolymer, and the inner layer includes 50 parts by mass of the second low-density polyethylene and 25 parts by mass of metallocene polyethylene), respectively adding the corona layer resin raw material, the middle layer resin raw material and the inner layer resin raw material to the three barrels of the extruder; after the raw materials in the three barrels are co-extruded, they enter the casting station for cooling and shaping, and then the surface of the corona layer of the film after the casting shaping is corona treated to obtain a barrier layer;

[0036] S2, printing the outer layer to obtain an outer layer printed film;

[0037] S3, the barrier layer and the outer printed film are dry-laminated, aged, and then extruded with the extrusion layer, followed by cooling and slitting in sequence to obtain a composite film 1.

[0038] Among them, the brand of the first low-density polyethylene is 2420H produced by BASF-YPC, the brand of ethylene-vinyl alcohol copolymer is ET3203FB produced by Japan Synthetic Chemical Co., Ltd., the brand of the second low-density polyethylene is LD100AC produced by Yanshan Petrochemical Co., Ltd., the brand of metallocene polyethylene is SP0510 produced by Japan Prime Co., Ltd.; the extruded layer uses ethylene-a-olefin resin, the brand is PT1450 produced by Dow Chemical Co.

[0039] Comparative Example 2

[0040] S1, weighing resin raw materials (formula: corona layer includes 100 mass parts of first low density polyethylene, middle layer includes 80 mass parts of first low density polyethylene and 20 mass parts of ethylene-vinyl alcohol copolymer, inner layer includes 50 mass parts of second low density polyethylene and 25 mass parts of metallocene polyethylene), respectively adding corona layer resin raw material, middle layer resin raw material and inner layer resin raw material to three barrels of extruder; after co-extruding the raw materials in the three barrels, entering the casting station for cooling and shaping, and then corona treating the surface of the corona layer of the film after casting and shaping to obtain a barrier layer;

[0041] S2, the outer layer, the barrier layer and the extruded layer are sequentially subjected to dry lamination, aging, extrusion, cooling and slitting to obtain a composite film 2.

[0042] Among them, the brand of the first low-density polyethylene is 2420H produced by BASF-YPC, the brand of ethylene-vinyl alcohol copolymer is ET3203FB produced by Japan Synthetic Chemical Co., Ltd., the brand of the second low-density polyethylene is LD100AC produced by Yanshan Petrochemical Co., Ltd., the brand of metallocene polyethylene is SP0510 produced by Japan Prime Co., Ltd.; the extruded layer uses ethylene-vinyl acetate copolymer, brand 7513 produced by Korea Helek.

[0043] The above comparative test is mainly to verify the heat sealing strength and easy opening of the inner layer EVA and the large cup body, that is, to maintain a good heat sealing strength without leakage and to have a good easy opening performance, so the materials and processes of the outer layer BOPA and the middle layer PE-EVA remain unchanged. The cover film 1 prepared in Example 1 and the composite film 1 and composite film 2 prepared in Comparative Examples 1-2 are all composited with the PP large cup body, and the measured heat sealing strength is shown in Table 1 below:

[0044] Table 1

[0045]

[0046] According to Table 1, the heat sealing strength of Example 1 after compounding with the PP large cup body at a heat sealing temperature of 120-170°C is higher than the heat sealing strength of Comparative Examples 1-2 after compounding with the PP large cup body, indicating that the cover film prepared by the present invention has high heat sealing strength with the PP large cup body.

[0047] The cover film 1 prepared in Example 1 and the composite films 1 and 2 prepared in Comparative Examples 1-2 were subjected to other performance tests, and the results are shown in Table 2 below:

[0048] Table 2

[0049]

[0050]

[0051] It can be seen from Table 2 above that the barrier data of the cover film 1 prepared in Example 1 and the composite films 1 and 2 prepared in Comparative Examples 1-2 are not much different, and the test results all meet the standard requirements, indicating that the cover film prepared by the present invention meets the barrier performance requirements; in addition, the heat sealing strength of the cover film 1 prepared in Example 1 is the highest, indicating that the cover film prepared by the present invention will not leak after being sealed with the large cup body, while the heat sealing strength of the composite films 1 and 2 prepared in Comparative Examples 1-2 does not meet the standard or just meets the standard, and there is a risk of leakage; in addition, the easy-to-peel performance of the cover film 1 prepared in Example 1 is better than the easy-to-peel performance of the composite films 1 and 2 prepared in Comparative Examples 1-2, satisfying the easy-to-peel experience of consumers.

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-strength easy-to-peel barrier cover film for large cups, characterized in that: It comprises an outer layer, a barrier layer and an extruded layer connected in sequence; the outer layer is made of BOPA material, the barrier layer comprises a corona layer, an intermediate layer and an inner layer arranged in sequence, the corona layer is connected to the outer layer, and the inner layer is connected to the extruded layer; the corona layer is composed of 100 parts by weight of a first low-density polyethylene, the intermediate layer is composed of 80 parts by weight of a first low-density polyethylene and 20 parts by weight of an ethylene-vinyl alcohol copolymer, and the inner layer is composed of 50 parts by weight of a second low-density polyethylene and 25 parts by weight of a metallocene polyethylene; the extruded layer is made of an ethylene-vinyl acetate copolymer; The high-strength easy-to-peel barrier cover film for large cups is prepared by the following preparation process, which comprises the following steps: S1. Add corona layer resin raw materials, middle layer resin raw materials and inner layer resin raw materials into three barrels of a film blowing machine according to the resin raw material formula; blow the raw materials in the three barrels and then cool them to shape them, and then perform corona treatment on the surface of the corona layer of the shaped film to obtain a barrier layer; S2, printing the outer layer to obtain an outer layer printed film; S3, the barrier layer and the outer printed film are dry-laminated and cured, and then extruded with the extrusion layer, and then cooled and cut in sequence to obtain the cover film.

2. The high-strength easy-to-peel barrier cover film for large cups according to claim 1, characterized in that: The brand of the first low-density polyethylene is 2420H produced by BASF-YPC, the brand of the second low-density polyethylene is LD100AC produced by Yanshan Petrochemical Company, the brand of the metallocene polyethylene is SP0510 produced by Japan Prime Co., Ltd.; the brand of the ethylene-vinyl acetate copolymer is 53007 produced by DuPont Company of the United States.

3. The high-strength easy-to-peel barrier cover film for large cups according to claim 1, characterized in that: The thickness ratio of the outer layer, the barrier layer and the extruded layer is 3:11:

7.

4. The high-strength easy-to-peel barrier cover film for large cups according to claim 3, characterized in that: The thickness ratio of the corona layer, the middle layer and the heat sealing layer is 2:7:

2.

5. A process for preparing a high-strength easy-to-peel barrier cover film for a large cup as claimed in any one of claims 1 to 4, characterized in that: The production process includes the following steps: S1. Add corona layer resin raw materials, middle layer resin raw materials and inner layer resin raw materials into three barrels of a film blowing machine according to the resin raw material formula; blow the raw materials in the three barrels and then cool them to shape them, and then perform corona treatment on the surface of the corona layer of the shaped film to obtain a barrier layer; S2, printing the outer layer to obtain an outer layer printed film; S3, the barrier layer and the outer printed film are dry-laminated and cured, and then extruded with the extrusion layer, and then cooled and cut in sequence to obtain the cover film.

6. The process for preparing a high-strength easy-to-peel barrier cover film for a large cup according to claim 5, characterized in that: The glue amount of the dry compound in step S3 is 3.4-3.8g / m 3 , the composite speed is 100±10m / min; the aging temperature is 55℃, and the aging time is 72h.

7. The process for preparing a high-strength easy-to-peel barrier cover film for a large cup according to claim 5, characterized in that: In the extrusion process in step S3, the extrusion temperature of the extruder is 235-245°C, the die processing temperature of the extruder is 235-245°C, and the casting roll processing temperature of the extruder is 20±3°C.

8. The process for preparing a high-strength easy-to-peel barrier cover film for a large cup according to claim 5, characterized in that: The cooling means that the composite film is placed for 24 hours after the extrusion process is completed, and then cut into pieces after the composite film is completely cooled to obtain the cover film.

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