CN220314415U

CN220314415U - High-barrier anti-fog cover film

Info

Publication number: CN220314415U
Application number: CN202321217512.4U
Authority: CN
Inventors: 刘明武; 高虎; 舒强; 张羽; 朱妙清; 冯润财
Original assignee: Amco Technology R&d Co ltd
Current assignee: Amco Technology R&d Co ltd
Priority date: 2023-05-18
Filing date: 2023-05-18
Publication date: 2024-01-09
Anticipated expiration: 2033-05-18

Abstract

The utility model relates to a high-barrier anti-fog cover film which sequentially comprises a printing layer, an adhesive layer, a first LDPE (low density polyethylene) layer, a second LDPE layer, a barrier layer, a third LDPE layer, a heavy-stick layer, a fourth LDPE layer, a fifth LLDPE layer and an anti-fog coating from top to bottom. The thickness of the printing layer is 12-50 mu m, the thickness of the bonding layer is 2-3 mu m, the thickness of the first LDPE layer is 20-30 mu m, the thickness of the second LDPE layer is 3-10 mu m, the thickness of the blocking layer is 5-10 mu m, the thickness of the third LDPE layer is 3-10 mu m, the thickness of the heavy bonding layer is 15-25 mu m, the thickness of the fourth LDPE layer is 15-25 mu m, the thickness of the fifth LLDPE layer is 5-10 mu m, and the thickness of the antifogging coating is 1-3 mu m.

Description

High-barrier anti-fog cover film

Technical Field

The utility model relates to the technical field of food packaging films, in particular to a high-barrier anti-fog cover film.

Background

This section provides background information related to the present application, which does not necessarily constitute prior art.

The package for foods to be stored in a low temperature environment is required to have high transparency, easy-to-uncover and anti-fog functions, and comprises a cover film and a transparent groove body container (or a base), wherein the cover film is heat-sealed on a notch of the groove body container. The packaging material of the packaging box gradually develops towards the directions of high barrier, no toxicity, aging resistance, high strength, co-extrusion film, composite film and environmental protection. The existing covering film is mainly produced by taking nylon or polypropylene as raw materials and adopting a composite or multilayer coextrusion process, and the structure of the existing covering film is mainly PP (namely a polypropylene layer), PET/Tie/PA/PA/PA/Tie/PE-AF (namely a polyethylene terephthalate layer/bonding layer/three nylon layers/bonding layer/polyethylene layer with anti-fog effect) or PA/Tie/PP/PVDC/PP/Tie/PA (namely a nylon layer/bonding layer/polypropylene layer/polyvinylidene chloride layer/polypropylene layer/bonding layer/nylon layer).

The packing box has the following technical problems: when the volume of the packaging box is large, a consumer cannot eat the food in the packaging box at one time, and the cover film of the packaging box cannot be sealed with the groove body container again after being uncovered, so that the food is wasted.

The term "antifogging function" used in the present utility model means that the water vapor liquefied when the cover is stored in an environment of 0 to 4 ℃ is formed into a transparent water film on the surface of the cover, so that the observation of the package in the container of the container body is not hindered.

Disclosure of Invention

Aiming at the technical problems in the prior art, the utility model provides the high-barrier anti-fog cover film, which can improve the display performance of a packaging box, has excellent barrier performance and anti-fog function, can be repeatedly opened and can be matched with a barrier forming collet or a groove body container so as to realize the effect that the cover film can be manually kneaded to be resealed after being uncovered.

In order to achieve the above purpose, the utility model adopts the following technical scheme: a high-barrier anti-fog cover film comprises a printing layer, an adhesive layer, a first LDPE (low density polyethylene) layer, a second LDPE layer, a barrier layer, a third LDPE layer, a heavy-stick layer, a fourth LDPE layer, a fifth LLDPE layer and an anti-fog coating which are sequentially arranged.

Wherein the printing layer is one or more of BOPET (biaxially oriented polyester film), BOPP (biaxially oriented polypropylene film), BOPE (biaxially oriented polyethylene film) and MDOPE (MDO stretched polyethylene film). The printing layer can endow the cover film with excellent glossiness, and more importantly, the cover film has excellent printing performance, so that the cover film can be directly printed without labeling, and is more beneficial to recycling. The printing layer does not adhere to the knife during heat sealing of the cover film. Preferably, the thickness of the printed layer is 12-50 μm.

The adhesive layer is formed after the polyurethane adhesive is cured. Preferably, the thickness of the adhesive layer is 2-3 μm.

Wherein the first LDPE layer has a thickness of 20-30 μm. From the viewpoint of improving the connection strength of the first LDPE layer and the adhesive layer, the contact end surfaces of the first LDPE layer and the adhesive layer are subjected to corona treatment.

Wherein the second LDPE layer provides a transition function of the barrier layer. Preferably, the second LDPE layer has a thickness of 3-10 μm.

Among them, the barrier layer EVOH layer, i.e., an ethylene-vinyl alcohol copolymer, has barrier properties depending on the ethylene content, and generally has a reduced gas barrier property when the ethylene content is increased, but is easy to process. The barrier layer can effectively block the gas of the external environment. Preferably, the thickness of the barrier layer is 5-10 μm.

Wherein the third LDPE layer provides a transition between the barrier layer and the heavy stick layer. Preferably, the thickness of the third LDPE layer is 3-10 μm.

Wherein the fourth LDPE layer provides a transition function of the heavy adhesive layer. Preferably, the fourth LDPE layer has a thickness of 15-25 μm.

The fifth LLDPE layer is a heat sealing layer, and the fifth LLDPE layer can be heat sealed with a bottom bracket or a groove body container. Preferably, the thickness of the fifth LLDPE layer is from 5 to 10 μm.

The anti-fog coating is coated on the end face, far away from the heavy-adhesion layer, of the fifth LLDPE layer, and can be used for tiling liquefied water vapor to achieve an anti-fog effect. Preferably, the thickness of the anti-fog coating is 1-3 μm.

When the high-barrier anti-fog cover film is uncovered, the heavy adhesive layer is torn into two parts, one part of the heavy adhesive layer is arranged on the uncovered cover film, the other part of the heavy adhesive layer is left on the bottom support or the groove body container along with the fifth LLDPE layer, and when the two parts of the heavy adhesive layer are in re-extrusion contact, repeated sealing packaging can be realized. Preferably, the thickness of the heavy adhesive layer is 15-25 μm. The heavy-adhesion layer has low haze, good transparency, good compatibility and ideal adhesion performance.

In one or more embodiments, the heavy stick layer is prepared using the adhesive product of Bostik (Bostik) company under the trademark M-Resin M650-F.

In one or more embodiments, the heavy stick layer is prepared using M-resin particles from Bostik (Boston gum).

In one or more embodiments, an anti-fog coating is applied to the fifth LLDPE layer from an anti-fog coating and cured, the anti-fog coating comprising the following components in parts by mass:

1 part of a nonionic surfactant, wherein the nonionic surfactant comprises sorbitol monolaurate and/or polyglycerol fatty acid ester;

1.5 parts of a modified surfactant comprising ethylene oxide and/or polyoxyethylene added glycerides or sorbitan monoesters;

80 parts of ethanol;

17.5 parts of ethyl acetate.

The anti-fog coating can be prepared by the following method:

step one, mixing 80 parts of absolute ethyl alcohol and 17.5 parts of ethyl acetate in advance to obtain a mixed solvent;

sequentially adding 1 part of nonionic surfactant and 1.5 parts of modified surfactant into a reaction kettle;

step three, adding 10 parts of mixed solvent into a reaction kettle, and pre-stirring for 5min;

and step four, after pre-stirring, adding the rest mixed solvent while stirring, and stirring for 20min to obtain the compounded anti-fog paint.

Because the adhesive product for preparing the heavy-stick layer has relatively large polarity, if particles with an anti-fog function are added into the fourth LDPE layer and the fifth LLDPE layer, the particles can easily attract the anti-fog agent due to the attraction of the polarity of the adhesive product for preparing the heavy-stick layer, and migrate to the contact end surface of the fourth LDPE layer and the heavy-stick layer inwards, so that the anti-fog agent cannot migrate to the other end surface of the fifth LLDPE heat sealing layer to realize the anti-fog function, and the overall anti-fog function is weakened and even disappears. Therefore, in the high-barrier anti-fog cover film provided by the utility model, the particles with an anti-fog function are not added in the fourth LDPE layer and the fifth LLDPE layer, but the anti-fog coating is coated on the end surface of the fifth LLDPE layer far away from the heavy-adhesion layer to form an anti-fog coating, so that the anti-fog coating is prevented from contacting with the heavy-adhesion layer.

In one or more embodiments, the steps of preparing the heavy stick layer and the anti-fog coating are: corona pretreatment is respectively carried out on the top end face of the fourth LDPE layer and the bottom end face of the fifth LLDPE layer, then an adhesive with the company brand name M-Resin M650-F is coated on the top end face of the fourth LDPE layer, an anti-fog coating is coated on the bottom end face of the fifth LLDPE layer, then high-temperature drying is carried out, and finally, a heavy-stick layer and an anti-fog coating are obtained through natural standing and curing.

In one or more embodiments, the heavy stick layer is prepared using a Bostik (Bostik) M-resin pellet and multilayer co-extrusion blown film process.

In one or more embodiments, release paper is arranged on one side of the anti-fog coating, and the cover film and the release paper are rolled simultaneously during rolling, so that loss of the anti-fog coating is avoided, and the release paper is peeled off and then is used on food packaging during use.

Compared with the prior art, the technical scheme provided by the utility model has at least the following beneficial effects:

the utility model provides a high-barrier anti-fog cover film which has a repeated opening function, excellent barrier performance and anti-fog function, and has an anti-fog coating effective period of up to 2 years, and excellent weather resistance (can resist aging at 70 ℃ for more than 1 week).

The following description is made with reference to specific embodiments.

Drawings

The utility model is further illustrated by the accompanying drawings, which are not to be construed as limiting the utility model in any way.

Fig. 1 is a schematic diagram of the hierarchical structure of the high-barrier anti-fog cover film provided in example 1.

Wherein, the reference numerals are as follows: a printing layer 1, an adhesive layer 2, a first LDPE layer 3, a second LDPE layer 4, a barrier layer 5, a third LDPE layer 6, a re-adhesive layer 7, a fourth LDPE layer 8, a fifth LLDPE layer 9 and an anti-fog coating 10.

Detailed Description

It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

The high-barrier anti-fog cover film provided by the embodiment of the utility model sequentially comprises a printing layer, an adhesive layer, a first LDPE layer, a second LDPE layer, a barrier layer, a third LDPE layer, a heavy-stick layer, a fourth LDPE layer, a fifth LLDPE layer and an anti-fog coating from top to bottom.

The preparation method of the high-barrier anti-fog cover film provided by the embodiment of the utility model comprises the following steps: firstly, preparing a first composite film consisting of a first LDPE layer, a second LDPE layer, a barrier layer, a third LDPE layer, a heavy-stick layer, a fourth LDPE layer and a fifth LLDPE layer by adopting a multilayer coextrusion film blowing process; then, a second composite film is obtained through the composite printing layer of the adhesive layer on the top end surface of the first composite film, and the second composite film is cured for 48 hours; and finally, preparing an anti-fog coating on the bottom end surface of the second composite film to obtain a third composite film, and curing the third composite film for 12 hours to obtain the high-barrier anti-fog cover film.

The first composite film is prepared by adopting a 7-layer coextrusion film blowing machine, and the temperatures of an extruder A, an extruder B, an extruder C, an extruder D, an extruder E, an extruder F and an extruder G, as well as the connector temperature, the die neck temperature, the in-die temperature and the die mouth temperature are set. And after the equipment reaches the set temperature, starting feeding. Wherein pellets of a low-density polyethylene resin are fed into an extruder A and an extruder B, pellets of an EVOH resin are fed into an extruder C, pellets of a low-density polyethylene resin are fed into an extruder D and an extruder E, pellets of an M-resin of Bostik (Bostik) company are fed into an extruder F, and pellets of a low-density polyethylene resin are fed into an extruder G.

The temperature of the extruder A is set as follows: first area 165 + -5 deg.c, second area 170 + -5 deg.c, third area 180 + -5 deg.c, fourth area 180 + -5 deg.c, screen change 180 + -5 deg.c and runner 180 + -5 deg.c;

the temperature of the extruder B is set as follows: first area 165 + -5 ℃, second area 170 + -5 ℃, third area 185 + -5 ℃, fourth area 185 + -5 ℃, screen change 185 + -5 ℃, runner 185 + -5 ℃;

the extruder C machine temperature is set as follows: first area 165 + -5 ℃, second area 180 + -5 ℃, third area 200 + -5 ℃, fourth area 220 + -5 ℃, screen change 220 + -5 ℃, runner 220 + -5 ℃;

the temperature of the extruder D machine is set as follows: first area 165 + -5 ℃, second area 170 + -5 ℃, third area 185 + -5 ℃, fourth area 185 + -5 ℃, screen change 185 + -5 ℃, runner 185 + -5 ℃;

the extruder E machine temperature is set as follows: 130+ -5 ℃ in the first area, 150+ -5 ℃ in the second area, 170+ -5 ℃ in the third area, 170+ -5 ℃ in the fourth area, 170+ -5 ℃ in the screen change area, 170+ -5 ℃ in the runner, and 170+ -5 ℃;

the temperature of the extruder F machine is set as follows: first area 165 + -5 deg.c, second area 170 + -5 deg.c, third area 180 + -5 deg.c, fourth area 180 + -5 deg.c, screen change 180 + -5 deg.c and runner 180 + -5 deg.c;

the temperature of the extruder G machine is set as follows: first area 165 + -5 deg.c, second area 170 + -5 deg.c, third area 180 + -5 deg.c, fourth area 180 + -5 deg.c, screen change 180 + -5 deg.c and runner 180 + -5 deg.c;

the temperature of the extruder is set so that the resin pellets are well melted and smoothly extruded.

The temperature of the connector is 200+/-10 ℃, the temperature of the mold neck is 200+/-10 ℃, the temperature of the mold inside is 200+/-10 ℃, the temperature of the mouth mold is 200+/-10 ℃, and the filter screen is 180-220 meshes.

The screw speed of the extruder A is set to 15-20 rpm, the screw speed of the extruder B is set to 20-25 rpm, and the screw speed of the extruder C is set to 25-30 rpm. The screw speed of extruder D was set to 20-25 revolutions per minute. The screw speed of the extruder E was set to 25-30 rpm, and the screw speed of the extruder F was set to 20-25 rpm. The screw speed of extruder G was set to 20-25 revolutions per minute.

The temperature of the ice machine was set to 16.+ -. 2 ℃, the traction tension was set to 14.0.+ -. 1kg, and the winding tension was set to 5.+ -. 1kg.

The temperature and traction tension of the ice machine are adjusted, the winding tension is set, the cooling air quantity and angle are adjusted, so that the film bubble is stable, the film is stably moved when the thickness deviation of the film is lower than +/-5%, the film can be smoothly wound on a winding paper tube, and winding is started to obtain a first composite film.

Example 1

As shown in figure 1, the high-barrier anti-fog cover film comprises a printing layer 1, an adhesive layer 2, a first LDPE layer 3, a second LDPE layer 4, a barrier layer 5, a third LDPE layer 6, a heavy adhesive layer 7, a fourth LDPE layer 8, a fifth LLDPE layer 9 and an anti-fog coating 10 which are sequentially arranged.

Wherein, printing layer 1 is BOPET.

Wherein the thickness of the printing layer 1 is 12 μm, the thickness of the adhesive layer 2 is 2 μm, the thickness of the first LDPE layer 3 is 20 μm, the thickness of the second LDPE layer 5 is 3 μm, the thickness of the barrier layer 5 is 5 μm, the thickness of the third LDPE layer 6 is 3 μm, the thickness of the heavy-stick layer 7 is 15 μm, the thickness of the fourth LDPE layer 8 is 15 μm, the thickness of the fifth LLDPE layer is 5 μm, and the thickness of the anti-fog coating 10 is 1 μm.

The high-barrier anti-fog cover film provided by the embodiment can be suitable for packaging chilled fresh meat with a shelf life of four days.

Example 2

The high-barrier anti-fog cover film comprises a printing layer 1, an adhesive layer 2, a first LDPE layer 3, a second LDPE layer 4, a barrier layer 5, a third LDPE layer 6, a heavy-stick layer 7, a fourth LDPE layer 8, a fifth LLDPE layer 9 and an anti-fog coating 10 which are sequentially arranged.

Wherein, printing layer 1 is BOPP.

Wherein the thickness of the printing layer 1 is 50 μm, the thickness of the adhesive layer 2 is 3 μm, the thickness of the first LDPE layer 3 is 30 μm, the thickness of the second LDPE layer 4 is 10 μm, the thickness of the barrier layer 5 is 10 μm, the thickness of the third LDPE layer 6 is 10 μm, the thickness of the heavy-stick layer 7 is 25 μm, the thickness of the fourth LDPE layer 8 is 20 μm, the thickness of the fifth LLDPE layer 9 is 8 μm, and the thickness of the anti-fog coating 10 is 3 μm.

The high-barrier anti-fog cover film provided by the embodiment can be suitable for packaging meat cooked food with a shelf life of about one month.

Example 3

Wherein, printing layer 1 is BOPE.

Wherein the thickness of the printing layer 1 is 30 μm, the thickness of the adhesive layer 2 is 2 μm, the thickness of the first LDPE layer 3 is 25 μm, the thickness of the second LDPE layer 4 is 6 μm, the thickness of the barrier layer 5 is 7 μm, the thickness of the third LDPE layer 6 is 6 μm, the thickness of the heavy adhesive layer 7 is 20 μm, the thickness of the fourth LDPE layer 8 is 25 μm, the thickness of the fifth LLDPE layer 9 is 10 μm, and the thickness of the anti-fog coating 10 is 2 μm.

The high-barrier anti-fog cover film provided by the embodiment can be suitable for packaging chilled meat with a shelf life of about one week.

Example 4

Wherein, printing layer 1 is MDOPE.

Wherein the thickness of the printing layer 1 is 40 μm, the thickness of the adhesive layer 2 is 2 μm, the thickness of the first LDPE layer 3 is 22 μm, the thickness of the second LDPE layer 4 is 4 μm, the thickness of the barrier layer 5 is 9 μm, the thickness of the third LDPE layer 6 is 4 μm, the thickness of the heavy adhesive layer 7 is 22 μm, the thickness of the fourth LDPE layer 8 is 25 μm, the thickness of the fifth LDPE layer 9 is 10 μm, and the thickness of the anti-fog coating 10 is 2 μm.

The high-barrier anti-fog cover film provided by the embodiment can be suitable for packaging meat cooked food with a shelf life of about half a month.

[ Performance test ]

The high barrier anti-fog films prepared in examples 1-4 were tested for tensile strength, heat seal strength, puncture resistance and anti-fog properties as follows:

1. tensile strength test was performed according to GBT 13022-1991 tensile Property test method for Plastic film, test conditions: the speed is 200mm/min;

2. the heat seal strength test is carried out according to the test standard of GBT 2358-98 heat seal strength, and the test conditions are as follows: the speed is 300mm/min;

3. puncture resistance strength test was performed according to GBT 21302-2007 composite film for packaging, general rules for bags, test conditions: a 1mm diameter needle at a speed of 50mm/min;

4. the antifogging property test is carried out according to GBT 31726-2015 plastic film antifogging property test method, and the test conditions are as follows: warm water (hot fog) at about 85 ℃ and refrigerator temperature are set to 0-4 ℃ (cold fog), and the anti-fog grade is as follows:

if the antifogging appearance effect is completely opaque and the visual chart is completely invisible, the antifogging grade is 5;

if the antifogging appearance effect is semitransparent, a plurality of water drops are arranged on the surface of the film, and the antifogging grade is 4 when the visual chart is visible below 0.1;

if the antifogging appearance effect is basically transparent, the surface of the film has more water drops, and the character body of the visual chart is deformed, the antifogging grade is grade 3;

if the antifogging appearance effect is good in transparency, a small amount of uneven large water drops are arranged on the film surface, and the definition of the visual acuity chart with the area of more than 50% is consistent with that before testing, the antifogging grade is grade 2;

if the antifogging appearance effect is completely transparent, no water drop exists, the definition of the visual acuity test chart is completely consistent with that before the test, and the antifogging grade is 1 grade.

The performance test data of the high barrier anti-fog films prepared in examples 1-4 are shown in Table 1.

TABLE 1

As can be seen from table 1, the high barrier anti-fog cover films provided in examples 1 to 4 have excellent tensile strength, heat seal strength, puncture resistance and anti-fog properties, which are improved with an increase in the total thickness of the film, because the film thickness is increased, the tensile strength and puncture are improved, but the strength increase caused by the increase in thickness is not significant.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.

Claims

1. The utility model provides a high separation antifog plastic film which characterized in that: the anti-fog coating comprises a printing layer, an adhesive layer, a first LDPE layer, a second LDPE layer, a barrier layer, a third LDPE layer, a heavy-stick layer, a fourth LDPE layer, a fifth LLDPE layer and an anti-fog coating in sequence from top to bottom; the thickness of the printing layer is 12-50 mu m, the thickness of the bonding layer is 2-3 mu m, the thickness of the first LDPE layer is 20-30 mu m, the thickness of the second LDPE layer is 3-10 mu m, the thickness of the blocking layer is 5-10 mu m, the thickness of the third LDPE layer is 3-10 mu m, the thickness of the heavy bonding layer is 15-25 mu m, the thickness of the fourth LDPE layer is 15-25 mu m, the thickness of the fifth LLDPE layer is 5-10 mu m, and the thickness of the anti-fog coating is 1-3 mu m.

2. The high barrier anti-fog cover film of claim 1, wherein: the printing layer is BOPET.

3. The high barrier anti-fog cover film of claim 1, wherein: the printing layer is BOPP.

4. The high barrier anti-fog cover film of claim 1, wherein: the printing layer is BOPE.

5. The high barrier anti-fog cover film of claim 1, wherein: the printing layer is MDOPE.

6. The high barrier anti-fog cover film of claim 1, wherein: the barrier layer is EVOH.