CN219338880U

CN219338880U - Multilayer barrier film structure for food packaging

Info

Publication number: CN219338880U
Application number: CN202223507273.4U
Authority: CN
Inventors: 杨少辉; 储江顺; 李薇薇; 毕宏海
Original assignee: Shanghai Bangzhong New Material Co ltd
Current assignee: Shanghai Bangzhong New Material Co ltd
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2023-07-14
Anticipated expiration: 2032-12-28

Abstract

The application relates to a multilayer barrier film structure for food packaging, including barrier layer, bonding resin layer, first polyethylene layer and the second polyethylene layer that sets gradually, the barrier layer includes one deck EVOH layer at least, just the EVOH layer with the ratio of the thickness of barrier layer is 0.2~0.5. The barrier film structure for food packaging has good barrier effect and good heat sealing performance.

Description

Multilayer barrier film structure for food packaging

Technical Field

The application relates to the field of food packaging technology, in particular to a multilayer barrier film structure for food packaging.

Background

Multilayer barrier films for food packaging are widely used for packaging food, grain, chemicals, electronic products and precision instruments due to the presence of a layer of oxygen-barrier material therein. Can prevent mildew of food and rust of precise instrument, and prolong shelf life of food and food. Therefore, the utility model designs a multilayer barrier film structure for food packaging, and achieves the barrier effect on water, carbon dioxide, smell and the like by utilizing the barrier performance characteristics of different plastic materials. The multi-layer barrier film has the characteristics of high strength and good heat sealing performance while ensuring oil resistance, cooking resistance and low temperature resistance.

EVOH is the most commonly used olefin plastic, and EVOH has been the most used high barrier material. The film type of the material is not stretched, but is also biaxially stretched, aluminum vapor deposited, adhesive coated and the like, and the biaxially stretched material is also heat resistant and used for aseptic packaging products. The barrier properties of EVOH depend on the ethylene content, and generally the gas barrier properties decrease when the ethylene content increases, but are easy to process.

EVOH is distinguished by excellent barrier properties against gases and excellent processability, and is additionally excellent in transparency, gloss, mechanical strength, stretchability, abrasion resistance, cold resistance and surface strength. In the packaging field, EVOH is made into a multi-layer barrier film intermediate barrier layer, and is applied to all rigid and flexible packages; in the food industry for aseptic packaging, hot cans and retort pouches, packaging dairy products, meats, fruit cans and condiments; in non-food applications, it is used for packaging solvents, chemicals, air conditioning structures, drum liners, and electronic components.

However, it is a great difficulty at present how to apply the EVOH material to food packaging using a heat sealing method because EVOH itself does not have heat sealing property.

Disclosure of Invention

In order to obtain a barrier film structure for food packaging with good barrier effect and good heat sealing performance, the application provides a multilayer barrier film structure for food packaging.

The application provides a multilayer barrier film structure for food packaging adopts following technical scheme:

the utility model provides a multilayer barrier film structure for food packaging, includes barrier layer, bonding resin layer, first polyethylene layer and the second polyethylene layer that sets gradually, the barrier layer includes one deck EVOH layer at least, just the EVOH layer with the ratio of the thickness of barrier layer is 0.2~0.5.

By adopting the technical scheme, the multilayer barrier film structure in the application comprises a five-layer structure, wherein the barrier layer with the EVOH layer can play a good role in barrier, and the thickness ratio of the EVOH layer in the barrier layer is not lower than 0.2 so as to ensure that the multilayer barrier film structure has a sufficient barrier effect; the EVOH layer has a thickness ratio of not more than 0.5 to ensure that the barrier layer has not only a good barrier effect but also good mechanical strength. In addition, the three-layer polyethylene layer structure specifically arranged in the application not only can form a good protection effect on the EVOH layer positioned inside, but also has good heat sealing performance and mechanical strength.

Optionally, the barrier layer comprises a first nylon layer, an EVOH layer and a second nylon layer which are sequentially arranged, and the ratio of the thickness of the barrier layer to the thickness of the barrier film structure is 0.3-0.5.

By adopting the technical scheme, the EVOH layer is arranged between the two nylon layers, so that good barrier effect and good heat sealing performance can be ensured.

Optionally, the thicknesses of the first nylon layer and the second nylon layer are d1 and d2 in sequence, and the thickness difference between d1 and d2 is not more than 10%; the thickness difference is calculated by the following formula:

by adopting the technical scheme, the first nylon layer and the second nylon layer are respectively positioned at two sides of the EVOH layer, so that the mechanical properties of the barrier layer are also determined to a great extent, and if the thickness difference of the first nylon layer and the second nylon layer is too large, the too large difference of the mechanical properties at two sides of the EVOH layer is likely to be caused; delamination easily occurs after compounding, and thus, it is necessary to control the thickness difference between the first nylon layer and the second nylon layer to be not more than 10%.

Optionally, the average thickness of the multi-layer barrier film is D, and the maximum thickness of the multi-layer barrier film structure is D _max Minimum thickness D with the multilayer barrier film structure _min The difference, with said D, is not more than 10%.

Through adopting above-mentioned technical scheme, the thickness homogeneity of multilayer separation membrane structure needs to be controlled in reasonable within range, if the thickness homogeneity of multilayer separation membrane structure is relatively poor, when using, the less regional weak department that can become mechanical properties of multilayer separation membrane structure thickness, the easy emergence is broken.

Optionally, the 180 ° peel strength of the barrier layer to the first polyethylene layer is not less than 6N/cm; the total number of colonies of the multi-layer barrier film structure is not more than 10cfu/cm ² 。

By adopting the technical scheme, the adhesive resin layer is arranged between the barrier layer and the first polyethylene layer, so that the two layers of structures are better adhered together, and the 180-degree peeling strength of the two layers of structures is not less than 6N/cm in order to ensure that layering phenomenon does not occur during use; in addition, the multilayer barrier film structure in the present application is used for food packaging, so the total number of colonies should be strictly controlled, should be not more than 10cfu/cm ² 。

Optionally, the transmittance of the multi-layer barrier film structure is not greater than 90%, and the gurley value of the multi-layer barrier film structure is not less than 10000s.

Optionally, the maximum tensile strength of the multi-layer barrier film structure is not less than 10Mpa, and the breaking tensile rate of the multi-layer barrier film structure is not less than 200%.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the multilayer barrier film structure in the application not only has good barrier effect, but also has good heat sealing effect and mechanical strength.

Drawings

Fig. 1 is a layer structure schematic diagram of a multilayer barrier film structure according to an embodiment of the present application.

Reference numerals illustrate: 1. a first nylon layer; 2. an EVOH layer; 3. a second nylon layer; 4. a bonding resin layer; 5. a first polyethylene layer; 6. a second polyethylene layer; 7. and a third polyethylene layer.

Detailed Description

The present application is described in further detail below in conjunction with fig. 1.

Examples

The embodiment of the application discloses a multilayer barrier film structure for food packaging, it includes barrier layer, bonding resin layer 4, first polyethylene layer 5, second polyethylene layer 6 and third polyethylene layer 7 that set gradually. Wherein the barrier layer comprises a first nylon layer 1, an EVOH layer 2 and a second nylon layer 3 which are sequentially arranged. The multi-layer barrier film structure is characterized in that a seven-layer coextrusion film blowing device is used, the heating temperature is set at 180-250 ℃, materials of each layer are conveyed through a screw rod of an extruder and enter a cavity of the extruder, after hot melting, the materials are extruded from a multi-layer die head of the extruder at the same time, and the structural product of the multi-layer barrier film for the food packaging film shown in figure 1 is finally obtained through the process links of extrusion, film blowing, cooling, rolling, cutting and the like.

In the multilayer barrier film structure, the ratio of the thickness of the EVOH layer 2 to the thickness of the barrier layer is 0.2 to 0.5, preferably 0.3 to 0.5. The thicknesses of the first nylon layer 1 and the second nylon layer 3 are d1 and d2 in sequence, and the thickness difference of d1 and d2 is not more than 10%; the thickness difference is calculated by the following formula:

the average thickness of the multi-layer barrier film is D, and the ratio of the difference between the maximum thickness Dmax of the multi-layer barrier film structure and the minimum thickness Dmin of the multi-layer barrier film structure to D is not more than 10%.

The 180 DEG peel strength of the barrier layer and the first polyethylene layer 5 is not less than 6N/cm; the total number of colonies of the multi-layer barrier film structure is not more than 10cfu/cm < 2 >; the transmittance of the multilayer barrier film structure is not more than 90%, and the gurley value of the multilayer barrier film structure is not less than 10000s; the maximum tensile strength of the multi-layer barrier film structure is not less than 10Mpa, and the breaking tensile rate of the multi-layer barrier film structure is not less than 200%.

The present embodiment is only for explanation of the present utility model and is not to be construed as limiting the present utility model, and modifications to the present embodiment, which may not creatively contribute to the present utility model as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present utility model.

Claims

1. A multilayer barrier film structure for food packaging, characterized in that: the adhesive comprises a barrier layer, an adhesive resin layer (4), a first polyethylene layer (5) and a second polyethylene layer (6) which are sequentially arranged, wherein the barrier layer at least comprises an EVOH layer (2), and the ratio of the thickness of the EVOH layer (2) to the thickness of the barrier layer is 0.2-0.5.

2. A multilayer barrier film structure for food packaging according to claim 1, wherein: the barrier layer comprises a first nylon layer (1), an EVOH layer (2) and a second nylon layer (3) which are sequentially arranged, and the ratio of the thickness of the barrier layer to the thickness of the barrier film structure is 0.3-0.5.

3. A multilayer barrier film structure for food packaging according to claim 2, wherein: the thicknesses of the first nylon layer (1) and the second nylon layer (3) are d1 and d2 in sequence, and the thickness difference between d1 and d2 is not more than 10%; the thickness difference is calculated by the following formula:

4. a multilayer barrier film structure for food packaging according to claim 1, wherein: the average thickness of the multilayer barrier film is D, and the ratio of the difference between the maximum thickness Dmax of the multilayer barrier film structure and the minimum thickness Dmin of the multilayer barrier film structure to the D is not more than 10%.

5. A multilayer barrier film structure for food packaging according to claim 1, wherein: the 180 DEG peel strength of the barrier layer and the first polyethylene layer (5) is not less than 6N/cm; the total number of colonies of the multilayer barrier film structure is not more than 10cfu/cm2.

6. A multilayer barrier film structure for food packaging according to claim 1, wherein: the transmittance of the multilayer barrier film structure is not more than 90%, and the gurley value of the multilayer barrier film structure is not less than 10000s.

7. A multilayer barrier film structure for food packaging according to claim 1, wherein: the maximum tensile strength of the multi-layer barrier film structure is not less than 10Mpa, and the breaking tensile rate of the multi-layer barrier film structure is not less than 200%.