WO2024022494A1

WO2024022494A1 - Barrier layer for packaging, and sheet-like composite layer for packaging and packaging container thereof

Info

Publication number: WO2024022494A1
Application number: PCT/CN2023/109860
Authority: WO
Inventors: 刘燕; 宁淑丽
Original assignee: 康美包（苏州）有限公司; 康美包服务股份公司
Priority date: 2022-07-29
Filing date: 2023-07-28
Publication date: 2024-02-01
Also published as: CN115257108A

Abstract

A barrier layer (20) for packaging, and a sheet-like composite layer (90) for packaging, and a packaging container (9) thereof. The barrier layer (20) for packaging does not comprise a metal layer, and the barrier layer (20) for packaging comprises a base layer (200) and a first barrier layer (201) stacked on the base layer (200); the base layer (200) mainly comprises a base layer mixture, and the base layer mixture comprises at least two base layer polymers; the first barrier layer (201) comprises a metal oxide; the at least two base layer polymers comprise a first base layer polymer and a second base layer polymer, and the first base layer polymer is different from the second base layer polymer, so that the barrier layer (20) for packaging has at least two melting point peaks.

Description

Barrier layer for packaging, sheet composite layer for packaging and packaging container thereof

Cross-references to related applications

This application is based on and claims priority to Chinese patent application No. 202210907813.3, titled "Barrier layer for packaging, sheet-like composite layer for packaging and packaging container thereof", which was submitted on July 29, 2022. The above-mentioned Chinese patent application is cited in its entirety here. The disclosure content of the patent application forms part of this application.

Technical field

The present disclosure relates to the field of packaging, and in particular to a packaging barrier layer, a packaging sheet composite layer and a packaging container thereof.

Background technique

Usually, packaging containers are made of sheet-like composite layers with a laminated structure. These packaging containers can be used to hold beverages or liquid foods, such as milk, juice, or yogurt. A laminated structure includes multiple layers arranged on top of each other, each layer having a different function. For example, the laminated structure may include: an ink layer for printing patterns, a paper base layer for supporting, an aluminum layer for blocking water and oxygen, and a sealing layer for sealing.

Contents of the invention

Embodiments of the present disclosure provide a barrier layer for packaging, a sheet-like composite layer for packaging, and a packaging container thereof.

According to a first aspect of the present disclosure, a packaging barrier layer is provided, wherein the packaging barrier layer does not include a metal layer, and the packaging barrier layer includes: a base layer, mainly including a base layer mixture, the base layer mixture Comprising at least two base layer polymers; a first barrier layer is stacked with the base layer and includes a metal oxide; wherein the at least two base layer polymers include a first base layer polymer and a second base layer Polymer, the first base layer polymer and the second base layer polymer are different, so that the packaging barrier layer has at least two melting point peaks.

In at least some embodiments, the at least two melting point peaks include a first melting point peak and a second melting point peak, and a difference between the first melting point peak and the second melting point peak is 5°C to 30°C.

In at least some embodiments, the first melting point peak is lower than the second melting point peak, the first melting point peak is 100°C to 130°C, and the second melting point peak is 120°C to 140°C.

In at least some embodiments, the base layer mixture further includes a third base layer polymer, and the A third base layer polymer is different from the first base layer polymer and the second base layer polymer such that the packaging barrier layer has at least three melting point peaks.

In at least some embodiments, the at least three melting point peaks include a first melting point peak, a second melting point peak, and a third melting point peak, and the difference between the first melting point peak and the second melting point peak is 5°C. ~30°C; the difference between the second melting point peak and the third melting point peak is 2°C~15°C.

In at least some embodiments, the third melting point peak is higher than the first melting point peak and lower than the second melting point peak, and the first melting point peak is 100°C to 130°C; the second melting point peak is 120℃～140℃; the third melting point peak is 110℃～125℃.

In at least some embodiments, the packaging barrier layer has a stretch ratio of 0 to 5.5.

In at least some embodiments, the stretch ratio of the packaging barrier layer is 4.5-5.

In at least some embodiments, the packaging barrier layer has a ratio of oxygen permeability under 70% relative humidity conditions to oxygen permeability under 50% relative humidity conditions of 2 to 10.

In at least some embodiments, under the condition of 50% relative humidity, the oxygen permeability of the packaging barrier layer ranges from 0.1 to 1.5cc/ ^m2 ·24 hours·atm; and under the condition of 70% relative humidity, the oxygen permeability range The oxygen permeability of the packaging barrier layer ranges from 1 to 15 cc/m ² ·24 hours·atm.

In at least some embodiments, the ratio of the longitudinal tensile strength to the transverse tensile strength of the packaging barrier layer is 2-10.

In at least some embodiments, the longitudinal tensile strength of the packaging barrier layer is 60-100Mpa; the transverse tensile strength of the packaging barrier layer is 10-30Mpa.

In at least some embodiments, the packaging barrier layer has a ratio of transverse elongation at break to longitudinal elongation at break of 5 to 35.

In at least some embodiments, the packaging barrier layer has a longitudinal elongation at break of 20% to 80%; the packaging barrier layer has a transverse elongation at break of 100% to 700%.

In at least some embodiments, the packaging barrier layer further includes: a second barrier layer located between the base layer and the first barrier layer, wherein the second barrier layer includes polyvinyl alcohol.

In at least some embodiments, the packaging barrier layer has a total thickness of 23 to 27 microns.

In at least some embodiments, the first base layer polymer includes a first polyolefin material, the second base layer polymer includes a second polyolefin material, the first polyolefin material and the second polyolefin material The materials differ from each other such that the packaging barrier layer has said at least two melting point peaks.

In at least some embodiments, the base layer mixture further includes a third base layer polymer, and the A third base layer polymer includes a third polyolefin material; the third polyolefin material is different from the first polyolefin material and the second polyolefin material such that the packaging barrier layer has at least three melting points peak.

In at least some embodiments, the first polyolefin material is one of high-density polyethylene, medium-density polyethylene, and low-density polyethylene; and the second polyolefin material is high-density polyethylene, medium-density polyethylene. , one of low-density polyethylene; the third polyolefin material is low-density linear polyethylene.

According to a second aspect of the present disclosure, there is provided a sheet-like composite layer for packaging, including: outer layers laminated sequentially in a direction from an outer surface of the packaging sheet-like composite layer to an inner surface of the packaging sheet-like composite layer. Covering layer, carrier layer, the aforementioned packaging barrier layer and inner covering layer.

According to a third aspect of the present disclosure, a packaging container is provided, which is folded from the aforementioned sheet-like composite layer for packaging.

According to a fourth aspect of the present disclosure, there is provided a sheet-like composite layer for packaging, comprising: packaging sequentially laminated in a direction from an outer surface of the packaging sheet-like composite layer to an inner surface of the packaging sheet-like composite layer. with a barrier layer; and an inner cover layer, which mainly includes a plurality of inner cover polymers, the plurality of inner cover polymers are all polyolefin materials and different from each other; the plurality of inner cover polymers include a first Inner covering layer polymer, the mass percentage of the first inner covering layer polymer in the inner covering layer is more than 35%.

In at least some embodiments, the inner cover layer includes: a first inner layer; and a second inner layer located between the first inner layer and the packaging barrier layer; the first inner cover layer polymer A first portion of the first inner cover layer polymer is distributed in the first inner layer, a second portion of the first inner cover layer polymer is distributed in the second inner layer; the first portion of the first inner cover layer polymer The mass percentage of the sum of the second part and the second part in the inner covering layer is more than 40%.

In at least some embodiments, the mass percentage of the first portion of the first inner cover polymer in the inner cover is greater than or equal to the mass percentage of the second portion of the first inner cover polymer in the inner cover. Mass percentage in the inner covering.

In at least some embodiments, the first inner layer and the second inner layer are in contact with each other, and the mass percent of the first portion of the first inner cover layer polymer in the first inner layer is equal to The mass percentage of the second portion of the first inner cover layer polymer in the second inner layer.

In at least some embodiments, the plurality of inner cover polymers further include a second inner cover polymer and a third inner cover polymer, the second inner cover polymer and the third inner cover polymer. polymers are different from the first inner cover polymer; from the second inner cover polymer and the The mass percentage of the mixture composed of the third inner covering layer polymer in the inner covering layer is greater than or equal to the mass percentage of the first inner covering layer polymer in the inner covering layer.

In at least some embodiments, the first portion of the mixture is distributed in the first inner layer, the second portion of the mixture is distributed in the second inner layer; the first portion of the mixture is in the The mass percentage in the first inner layer is equal to the mass percentage of the second portion of the mixture in the second inner layer.

In at least some embodiments, the mass percentage of the first portion of the first inner cover layer polymer in the first inner layer is 40% to 50%, and the first portion of the mixture is in the first inner layer. The mass percentage of an inner layer is 50% to 60%; and the mass percentage of the second part of the mixture in the second inner layer is 50% to 60%, and the first inner covering layer is polymerized The mass percentage of the second part of the material in the second inner layer is 40% to 50%.

In at least some embodiments, the inner cover layer further includes: a third inner layer located between the second inner layer and the packaging barrier layer, the third inner layer being composed of a third portion of the mixture. constitute.

In at least some embodiments, the first inner layer and the second inner layer are not in contact with each other, and the mass percentage of the first portion of the first inner cover layer polymer in the first inner layer is less than The mass percentage of the second portion of the first inner cover layer polymer in the second inner layer.

In at least some embodiments, the inner cover layer further includes: a fourth inner layer located between the first inner layer and the second inner layer; and the plurality of inner cover layer polymers further include a second inner layer. a cover layer polymer and a third inner cover layer polymer, the second inner cover layer polymer and the third inner cover layer polymer being different from the first inner cover layer polymer; from the second inner cover layer polymer A mixture of inner cover polymer and third inner cover polymer is distributed in at least one of the first inner layer and the fourth inner layer.

In at least some embodiments, the mixture is distributed only in the first inner layer, and the fourth inner layer is composed of one of the second inner cover polymer and the third inner cover polymer.

In at least some embodiments, a portion of the mixture is distributed in the first inner layer and another portion of the mixture is distributed in the fourth inner layer.

In at least some embodiments, the first inner cover polymer is metallocene polyethylene; the second inner cover polymer is high density polyethylene; and the third inner cover polymer is low density polyethylene. .

In at least some embodiments, the packaging sheet composite layer further includes: a first adhesive layer located between the packaging barrier layer and the inner cover layer, wherein the melting point of the first adhesive layer It is 95℃～105℃.

According to a fifth aspect of the present disclosure, a packaging container is provided, which is folded from the aforementioned sheet-like composite layer for packaging.

According to a sixth aspect of the present disclosure, there is provided a sheet-like composite layer for packaging, comprising: packaging sequentially laminated in a direction from an outer surface of the packaging sheet-like composite layer to an inner surface of the packaging sheet-like composite layer. With a barrier layer; and an inner covering layer, the inner covering layer mainly includes a plurality of inner covering layer polymers, wherein the differential scanning calorimetry of the layer structure with the packaging barrier layer and the inner covering layer The graph includes peak _A at temperature TA and peak B at temperature _TB , which temperature _TB is greater than the temperature _TA .

In at least some embodiments, the temperature _TA is at least 90°C.

In at least some embodiments, the temperature _TA is 90-110°C.

In at least some embodiments, the temperature _TB is 120-140°C.

In at least some embodiments, the characteristic of the peak A is the melting enthalpy H _A , the characteristic of the peak B is the melting enthalpy H _B , and the ratio of the melting enthalpy H _A to the melting enthalpy H _B ranges from 1:10 to 1 :5.

In at least some embodiments, the absolute value of the difference between the temperature _TB and the temperature _TA is at least 25°C.

In at least some embodiments, the absolute value of the difference between the temperature _TB and the temperature _TA is no more than 40°C.

In at least some embodiments, the inner cover layer essentially includes a plurality of inner cover polymers, the plurality of inner cover polymers are all polyolefin materials and are different from each other, wherein the plurality of inner cover polymers It includes a first inner covering layer polymer, and the mass percentage of the first inner covering layer polymer in the inner covering layer is more than 35%.

In at least some embodiments, the packaging sheet composite layer includes the aforementioned inner cover layer.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure and do not limit the present disclosure. .

Figure 1 is a schematic diagram of the expansion of the sheet composite layer;

Figure 2 is a schematic structural diagram of the packaging container;

Figure 3 is a schematic cross-sectional view of a laminated material of a sheet-like composite layer for packaging according to an embodiment of the present disclosure;

Figure 4A is a DSC curve of a sheet-like composite layer for packaging according to an embodiment of the present disclosure;

Figure 4B is a DSC curve of a sheet-like composite layer for packaging according to another embodiment of the present disclosure;

Figure 5 is a schematic cross-sectional view of the light shielding layer according to an embodiment of the present disclosure;

Figure 6 is a schematic cross-sectional view of the inner covering layer according to an embodiment of the present disclosure;

Figure 7 is a schematic cross-sectional view of the inner covering layer according to another embodiment of the present disclosure;

Figure 8 is a schematic cross-sectional view of the inner covering layer according to yet another embodiment of the present disclosure;

Figure 9 is a schematic cross-sectional view of a laminated material of a sheet-like composite layer for packaging according to another embodiment of the present disclosure;

Figure 10 is a schematic cross-sectional view of a laminated material of a sheet-like composite layer for packaging according to yet another embodiment of the present disclosure;

Figure 11 is a schematic cross-sectional view of a laminated material of a sheet-like composite layer for packaging provided by yet another embodiment of the present disclosure;

Figure 12 is a DSC graph of a layer structure composed of an inner cover layer and a packaging barrier layer according to an embodiment of the present disclosure;

Figure 13 is a DSC curve of a layer structure composed of an inner cover layer and a packaging barrier layer according to another embodiment of the present disclosure;

Figure 14 is a DSC graph of a layer structure composed of an inner cover layer and a packaging barrier layer according to yet another embodiment of the present disclosure.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present disclosure.

Unless otherwise defined, technical or scientific terms used herein shall have their ordinary meaning understood by a person of ordinary skill in the art to which this disclosure belongs. "First", "second" and similar words used in the specification and claims of this patent application do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "include" or "distribute" and similar words mean that the elements or things appearing before "include" or "distribute" cover the elements or things listed after "include" or "distribute" and their equivalents, and do not exclude others. Component or object. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to express relative position relationships. When the absolute position of the described object changes, the relative position The placement relationship may also change accordingly.

Figure 1 is a schematic diagram of the unfolded sheet composite layer. Figure 2 is a schematic structural diagram of the packaging container.

As shown in Figure 1, the sheet composite layer 90 is in an unfolded state and includes a crease pattern. For the sake of simplicity, Figure 1 only shows the main crease lines. For example, the crease pattern includes two transverse crease lines extending along the first direction D1 and a plurality of longitudinal crease lines extending along the second direction D2. The second direction D2 is perpendicular to the first direction D1. After the sheet-like composite layer 90 is folded and sealed according to the crease pattern, the packaging container 9 of Figure 2 can be formed.

As shown in Figure 2, the packaging container 9 includes a bottom BP, a top TP, and a side wall SP located between the bottom BP and the top TP. The top TP has an opening (not shown) for the contents to flow out, which is covered with a screw cap. The side wall SP includes a longitudinal seam 94 formed by mutually sealing the two end regions 90A and 90B of the sheet-like composite layer 90 . The longitudinal seam 94 extends in the second direction D2 from bottom BP to top TP.

Typically, the sheet composite layer 90 includes a paper base layer and a sealing layer. The longitudinal seams 94 of the packaging container 9 can be formed by heating the sealing layers in the end regions 90A, 90B and sealing them to each other. The sealing layer includes a barrier layer that blocks water and oxygen. The barrier layer is easily softened by heat under high temperature conditions, causing changes in its internal molecular structure, resulting in a decrease in its water and oxygen barrier properties, which in turn leads to the deterioration of the entire packaging container. The water and oxygen blocking performance is reduced.

To this end, embodiments of the present disclosure provide a packaging barrier layer, a packaging sheet composite layer and a packaging container, which can improve the water and oxygen barrier properties of the packaging container.

Embodiments of the present disclosure provide a packaging barrier layer that does not include a metal layer and includes a base layer and a first barrier layer. The matrix layer essentially includes a matrix layer mixture that includes at least two matrix layer polymers. The first barrier layer is stacked with the base layer and includes a metal oxide. The at least two base layer polymers include a first base layer polymer and a second base layer polymer, and the first base layer polymer and the second base layer polymer are different such that the packaging barrier layer has at least two melting point peaks.

In the embodiment of the present disclosure, the melting point peak refers to the temperature when the material changes from a solid state to a liquid state (such as a molten state), which is also called the melting point or melting temperature. Usually, the melting point peak can be determined by the DSC (Differential Scanning Calorimetry, Differential Scanning Calorimetry) curve of the test material. When the barrier layer provided by the embodiment of the present disclosure is heated, the base layer mixture is also heated at the same time, so that at least two melting point peaks, such as two or three melting point peaks, will appear in the DSC curve.

In the embodiment of the present disclosure, the polymer of the first base layer and the polymer of the second base layer may be different from each other. The materials of the first base layer polymer and the second base layer polymer are different, for example, polymers with different molecular weights, and/or polymers with different crystallinity, and/or polymers with different densities.

In the packaging barrier layer provided in the above embodiments, due to having at least two different first base layer polymers and second base layer polymers, the packaging barrier layer has at least two melting point peaks, which brings about a The advantage is that when the packaging container is sealed, due to the difference in melting point peaks, one of the first base layer polymer and the second base layer polymer enters a molten state first, and the other enters a molten state later. That is, as the temperature increases during sealing, the base layer polymer with a lower melting point peak enters the molten state first, and then the base layer polymer with a higher melting point peak enters the molten state.

The inventor found that conventional packaging barrier layers do not have multiple melting point peaks, which causes the materials of the barrier layer to be heated and melted together when the barrier layer is heated and sealed, causing the layer structure to undergo large deformation and easily causing bubbles.

By making the packaging barrier layer have at least two melting point peaks, this application avoids the rapid deformation of the layer structure of the barrier layer due to temperature changes, thus avoiding the occurrence of the barrier layer under high-temperature heating conditions (for example, 300°C to 400°C). The phenomenon of bubbling ensures that the packaging material with the barrier layer provided by this application can complete the heat sealing process in a wider temperature window (ie, a wider temperature range) when filling and sealing. At the same time, another benefit is that the use of two different base layer polymers ensures the stiffness and tensile strength of the barrier layer film, so that the barrier layer of the present application can meet the process strength requirements of the composite production line.

The present disclosure is described below through several specific embodiments. In order to keep the following description of the embodiments of the present disclosure clear and concise, detailed descriptions of well-known functions and known components may be omitted. When any component of an embodiment of the present disclosure appears in more than one drawing, the component may be designated by the same reference number in each drawing.

3 is a schematic cross-sectional view of a laminate material of a sheet-like composite layer for packaging according to an embodiment of the present disclosure. As shown in Figure 3, for example, the sheet-like composite layer for packaging provided by the embodiment of the present disclosure includes an outer covering layer 40 and a carrier layer sequentially laminated in the direction from its outer surface to its inner surface (such as the Z direction shown in the figure). 30. Packaging barrier layer 20 and inner covering layer 10.

The outer covering layer 40 can be coated with a mimeograph layer, which has a printed pattern and is used for product introduction or promotion. The outer covering layer 40 mainly includes polyolefin material, such as low density polyethylene (LDPE).

The carrier layer 30 plays a supporting role. For example, the carrier layer is a paper layer, and the paper layer is at least one of cardboard or paper.

The packaging barrier layer 20 can block water and oxygen. In the Z direction, the packaging barrier layer 20 is located on the opposite side of the carrier layer 30 from the outer covering layer 40 , that is, the packaging barrier layer 20 and the outer covering layer 40 are located on opposite sides of the carrier layer 30 respectively.

For example, packaging barrier layer 20 does not include a metal layer. In known packaging containers, metal materials such as aluminum foil are usually used as packaging barrier layers to block water vapor or oxygen. However, the packaging barrier layer 20 provided by the embodiment of the present disclosure does not include any metal layer, that is, it does not include any metal element or alloy. Therefore, compared with the barrier layer using metal materials, it is conducive to the recycling and reuse of packaging containers, reducing or even eliminating damage to the environment.

As shown in FIG. 3 , for example, the packaging barrier layer 20 includes a base layer 200 , a first barrier layer 201 and a second barrier layer 202 . The second barrier layer 202 is located between the base layer 200 and the first barrier layer 201 .

The base layer 200 essentially includes a base layer mixture including at least two base layer polymers. For example, the at least two base layer polymers include a first base layer polymer and a second base layer polymer, and the first base layer polymer and the second base layer polymer are different such that the packaging barrier layer 20 has at least two melting points. peak.

For example, the base layer mixture is a polyolefin material. In this case, the first base layer polymer is the first polyolefin material, and the second base layer polymer is the second polyolefin material. The first polyolefin material and the second polyolefin material are different. Due to having two different polyolefin materials, the base layer mixture has two different melting point peaks, so that the packaging barrier layer also has two melting point peaks.

For example, the polyolefin material is at least one of polyethylene and polypropylene, preferably polyethylene. For example, the first polyolefin material is a first polyethylene, and the second polyolefin material is a second polyethylene.

For example, the first polyethylene is one of low density polyethylene (LDPE), medium density polyethylene (MDPE) and high density polyethylene (HDPE), and the second polyethylene is low density polyethylene. Another of polyethylene (LDPE), medium density polyethylene (MDPE) and high density polyethylene (HDPE). Due to the use of two different materials of polyethylene, the collective layer mixture has two different melting point peaks, so that the packaging barrier layer 20 also has two melting point peaks.

The density of low-density polyethylene is 0.910~0.940g/cm ³ . Low density polyethylene is the lightest variety among polyethylene resins. Compared with high-density polyethylene, its crystallinity (55% ~ 65%) and softening point (90 ~ 100℃) are lower; it has good flexibility, extensibility, transparency, cold resistance and processability; its chemical It has good stability and can resist acid, alkali and salt aqueous solutions; it has good electrical insulation and breathability; it has low water absorption; it is easy to burn. It is soft in nature, has good extensibility, electrical insulation, chemical stability, Processing performance and low temperature resistance (can withstand -70℃).

The density of medium density polyethylene is 0.926~0.940g/cm ^3. It is a polyethylene with the same properties as low density polyethylene. Due to the increase in density, the crystallinity of medium density polyethylene is as high as 70%~80%, while the density And the increase in crystallinity will increase the melting temperature of medium density polyethylene, the hardness and strength of the product.

The density of high-density polyethylene is 0.940~0.976g/cm ³ . It is a highly crystalline, non-polar thermoplastic resin produced by the copolymerization of ethylene. The appearance of original HDPE is milky white, and it is translucent to a certain extent in thin sections. It has excellent resistance to most domestic and industrial chemicals. It can resist the corrosion and dissolution of strong oxidants (concentrated nitric acid), acid and alkali salts, and organic solvents (carbon tetrachloride). The polymer is non-hygroscopic and has good waterproof vapor properties, and can be used for moisture-proof and seepage-proof purposes.

In some embodiments, the base layer mixture is a uniaxially oriented polymer, such as uniaxially oriented polyethylene (Machine direction oriented-polyethylene, MDOPE), also known as uniaxially oriented polyethylene film. The film has high rigidity and can be used in high-temperature industries. It also has increased elasticity and can withstand greater weight and temperature without cracking. It also has excellent light transmittance and printability. When it is uniaxially stretched polyethylene, the base layer mixture may also include the first polyethylene and the second polyethylene described in the previous embodiments, which will not be described again here.

For example, the two melting point peaks of the packaging barrier layer 20 include a first melting point peak and a second melting point peak, and the difference between the first melting point peak and the second melting point peak is 5°C to 30°C. By setting the difference between the first melting point peak and the second melting point peak to be 5°C to 30°C, it is possible to further ensure that the barrier layer has two different melting point peaks without changing the sealing temperature, thus avoiding the need for layer The structure undergoes rapid deformation due to temperature changes, which avoids the bubbling of the barrier layer under high-temperature heating, ensuring that the packaging material with the barrier layer provided by this application can be filled and sealed within a relatively short period of time. The heat sealing process is completed under a wide temperature window.

In some embodiments, the difference between the first melting point peak and the second melting point peak is 10°C to 25°C, preferably 10°C to 20°C, and more preferably 14°C to 17°C.

In the embodiments of the present disclosure, the first melting point peak value may be higher than the second melting point peak value, or the second melting point peak value may be higher than the first melting point peak value, as long as the difference between the first melting point peak value and the second melting point peak value is 5℃～30℃ is enough. The embodiments of the present disclosure take the second melting point peak value to be higher than the first melting point peak value as an example for explanation.

In some embodiments, the second melting point peak is greater than the first melting point peak, and the difference between the first melting point peak and the second melting point peak is 10°C to 40°C.

For example, the first melting point peak ranges from 100°C to 130°C; the second melting point peak ranges from 120°C to 140°C. Pass The above settings are conducive to selecting a suitable polyolefin material to form the matrix layer mixture, which not only reduces manufacturing costs, but also helps ensure the stiffness and tensile strength of the barrier layer film, so that the barrier layer can meet the process strength requirements of the composite production line.

Preferably, the first melting point peak is 105°C to 120°C, more preferably 110°C to 115°C; for example, the first melting point peak is approximately 110°C, 111°C, 112°C, 113°C, 114°C or 115°C.

Preferably, the second melting point peak is 120°C to 130°C, more preferably 122°C to 128°C; for example, the second melting point peak is approximately 120°C, 121°C, 122°C, 123°C, 124°C, 125°C, 126°C ℃, 127℃, 128℃.

For some packaging materials with special performance requirements, such as good oxygen barrier effect, high drop, light-proof storage, puncture resistance, etc., simply setting the base layer cannot meet the above requirements. As shown in FIG. 3 , the first barrier layer 201 is located on the base layer 200 , is stacked with the base layer 200 , and includes a metal oxide (AlOx). By disposing the first barrier layer 201 on the base layer 200, not only the water and oxygen barrier properties of the barrier layer can be further improved, but also the drop resistance and puncture resistance of the uniaxially stretched polyethylene film can be improved.

Metal Oxide A suitable metal oxide in the art can be selected to achieve a blocking effect against light, vapor and/or gas. Preferably, the metal oxide is a metal oxide of aluminum, iron, copper or titanium, more preferably alumina.

As shown in FIG. 3 , the second barrier layer 202 is located between the first barrier layer 201 and the base layer 200 to enhance the bonding strength between the base layer 200 and the first barrier layer 201 and further improve the barrier properties of the packaging barrier layer 20 . oxygen performance. For example, the second barrier layer includes polyvinyl alcohol (Poly(vinyl alcohol), PVA).

In known barrier layers, metal oxides such as aluminum oxide (AlOx) are usually formed on a base layer such as polyethylene terephthalate (PET). However, AlOx is formed on the PET layer. , not only the cost is high, but also the distribution uniformity and density of AlOx are difficult to control.

In the embodiment of the present disclosure, the liquid second barrier layer 202 (for example, PVA) is first applied on the base layer 200 and allowed to solidify, and then the first barrier layer 201 (for example, AlOx) is electroplated onto the second barrier layer 202. A packaging barrier layer 20 is formed. In this way, not only can the bonding strength between the base layer 200 and the first barrier layer 201 be improved, but also when the first barrier layer 201 is formed on the second barrier layer 202, the process controllability is higher, the cost is lower, and the process can be better achieved. The distribution uniformity and density of AlOx on the second barrier layer 202 are controlled to ensure high quality uniformity of the final product.

In embodiments of the present disclosure, the base layer mixture may include more than two base layer polymers, so that The packaging barrier layer 20 has multiple melting point peaks.

For example, the base layer mixture further includes a third base layer polymer that is different from the first base layer polymer and the second base layer polymer such that the packaging barrier layer 20 has at least three melting point peaks.

In the embodiment of the present disclosure, the third base layer polymer is different from the first base layer polymer and the second base layer polymer. The third base layer polymer may be the same as the first base layer polymer and the second base layer polymer. The materials are different, for example, the three are polymers with different molecular weights, and/or polymers with different crystallinity, and/or polymers with different densities.

Due to having three different first base layer polymers, second base layer polymers and third base layer polymers, the packaging barrier layer has three melting point peaks, which brings a benefit that when the packaging container is processed During sealing, due to the differences in multiple melting point peaks, the first base layer polymer, the second base layer polymer and the third base layer polymer respectively enter a molten state as the temperature increases. Compared with a barrier layer that only has a single melting point peak, the above arrangement can avoid the layer structure of the barrier layer from being drastically deformed due to temperature changes, thereby further avoiding blistering of the barrier layer under high-temperature heating. At the same time, three different base layer polymers are used to ensure the stiffness and tensile strength of the barrier layer film, so that the barrier layer of this application can meet the process strength requirements of the composite production line.

For example, the three melting point peaks include the first melting point peak, the second melting point peak and the third melting point peak. The difference between the first melting point peak and the second melting point peak is 5°C to 30°C; the second melting point peak and the third melting point peak The difference between the melting point peaks is 2°C to 15°C. By setting the difference between the first melting point peak and the second melting point peak to be 5°C to 30°C, and the difference between the second melting point peak and the third melting point peak to be 2°C to 15°C, sealing can be achieved without changing the Under the premise of temperature, it is further ensured that the barrier layer 20 has three melting point peaks, which avoids the rapid deformation of the layer structure of the barrier layer due to temperature changes, avoids the phenomenon of blistering of the barrier layer under high-temperature heating, and ensures that the band Packaging materials with the barrier layer provided by this application can complete the heat sealing process under a wide temperature window when filling and sealing.

In some embodiments, the difference between the second melting point peak and the third melting point peak is 2°C to 11°C, preferably 2°C to 4°C.

In the embodiments of the present disclosure, the third melting point peak may be higher than the first melting point peak and lower than the second melting point peak, or may be higher than the second melting point peak, as long as the difference between the second melting point peak and the third melting point peak is It can be 2℃～15℃. The embodiments of the present disclosure take the third melting point peak value to be higher than the first melting point peak value and lower than the second melting point peak value as an example to illustrate.

In some embodiments, the third melting point peak is higher than the first melting point peak and lower than the second melting point peak, And the difference between the second melting point peak and the third melting point peak is 2°C to 15°C.

For example, the first melting point peak is 100-130°C; the second melting point peak is 120-140°C; and the third melting point peak is 110°C-125°C. Through the above settings, it is helpful to select a suitable polyolefin material to form the matrix layer mixture, which not only reduces the manufacturing cost, but also helps ensure the stiffness and tensile strength of the barrier layer film, so that the barrier layer can meet the process strength requirements of the composite production line.

Preferably, the third melting point peak is between 120°C and 125°C. For example, the third melting point peak is approximately 120°C, 121°C, 122°C, 123°C, 124°C or 125°C.

In some embodiments, when the base layer mixture is a polyolefin material, the first base layer polymer is a first polyolefin material, the second base layer polymer is a second polyolefin material, and the third base layer polymer is a third polyolefin material, and the first polyolefin material, the second polyolefin material and the third polyolefin material are different. Since there are three different polyolefin materials, the base layer mixture has three different melting point peaks, so that the packaging barrier layer also has three melting point peaks.

For example, the first polyolefin material is a first polyethylene, the second polyolefin material is a second polyethylene, and the third polyolefin material is a third polyethylene. For example, the third polyethylene is low density linear polyethylene (Linear low density polyethylene, LLDPE).

The density of low-density linear polyethylene is between 0.915 and 0.935g/ ^cm3 . It is composed of ethylene and a small amount of higher α-olefins (such as butene-1, hexene-1, octene-1, tetramethylpentene-1 etc.) is a copolymer formed by high- or low-pressure polymerization under the action of a catalyst. The molecular structure of conventional low-density linear polyethylene is characterized by its linear main chain, with only a small amount or no long branches, but contains some short branches. chain. The absence of long chain branches makes the polymer more crystalline. Compared with LDPE, LLDPE has the advantages of high strength, good toughness, strong rigidity, heat resistance, and cold resistance. It also has good resistance to environmental stress cracking, tear strength, and resistance to acids, alkalis, organic solvents, etc.

For example, the stretch ratio of the packaging barrier layer 20 is 0 to 5.5, such as 4 to 5.5. The draw ratio is the ratio of the length of the specimen after stretching to the length of the initial specimen. If the length after stretching is 10 and the length before stretching is 1, the stretching ratio is 10. If the stretch ratio is too high (for example, higher than 5.5) or too low (for example, lower than 4), the packaging barrier layer 20 will easily break near the straw hole of the packaging container, and the edges will have ruffles and wrinkles, resulting in waste products. rate increases. Preferably, the stretch ratio of the packaging barrier layer 20 is 4.5-5. Through the setting of the above stretch ratio, edge wrinkles that may occur when the barrier layer is processed by a composite process are avoided. Specifically, when the heat sealing layer is further applied on the barrier layer through a composite processing process, the barrier layer needs to be opened from the roll state into the roller, and then molten PE is applied to the composite lamination process. When the roll is in the open state, it needs to be The movement between different rollers is therefore blocked When the layer moves between different rollers, it will be stretched by the rollers. If the stretch ratio of the barrier layer does not reach 4.5-5, then after the barrier film is stretched by the rollers, the edges of the film will wrinkle to varying degrees and cannot be used. in the later composite processing process.

In the embodiment of the present disclosure, the oxygen permeability (Oxygen permeability, also called oxygen permeability) of the packaging barrier layer 20 under the condition of 70% relative humidity is higher than the oxygen permeability under the condition of 50% relative humidity, because when the relative humidity As it increases, the oxygen permeability requirements also decrease accordingly.

For example, the ratio of the oxygen permeability of the packaging barrier layer 20 under the condition of 70% relative humidity to the oxygen permeability under the condition of 50% relative humidity is 2 to 10.

In some embodiments, the ratio of the oxygen permeability of the packaging barrier layer 20 under the condition of 70% relative humidity to the oxygen permeability under the condition of 50% relative humidity is 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10. For example, under the condition of 50% relative humidity, the oxygen permeability of the packaging barrier layer 20 is 0.5 to 1.5 cc/m ² ·24 hours·atm, and further, for example, is 1 cc/m ² ·24 hours·atm. Under the condition of 70% relative humidity, the oxygen permeability of the packaging barrier layer 20 is 1 to 15 cc/m ² ·24 hours·atm, and further, for example, is 6.0 cc/m ² ·24 hours·atm.

The water permeability of polymer films is related to its structure. The water permeability of polar films is greater than non-polar films, and the water permeability of amorphous films is greater than crystalline films. In the embodiment of the present disclosure, moisture permeability refers to water vapor transmission rate. For example, the moisture permeability (Moisture permeability) of the packaging barrier layer 20 is 10 g/m ² ·24 hours or less, and further, for example, it is 5 g/m ² ·24 hours or less.

For example, the ratio of the longitudinal tensile strength to the transverse tensile strength of the packaging barrier layer 20 is 2 to 10. In order to produce composite packaging materials (such as cardboard and barrier layers), the barrier layer needs to have certain mechanical processing properties, such as meeting the tension requirements between rollers. Through the above arrangement, the packaging barrier layer 20 can satisfy the lamination and composite processing technology. In some embodiments, the ratio of the longitudinal tensile strength to the transverse tensile strength of the packaging barrier layer 20 is 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 ,9,9.5,10.

Further, for example, the longitudinal tensile strength of the packaging barrier layer 20 is 60 to 100 MPa; the transverse tensile strength of the packaging barrier layer 20 is 10 to 30 MPa.

For example, the ratio of the transverse elongation at break to the longitudinal elongation at break of the packaging barrier layer 20 is 1.25 to 35. Further, for example, the longitudinal breaking elongation of the packaging barrier layer 20 is 20% to 80%; the transverse breaking elongation of the packaging barrier layer 20 is 100% to 700%. Through the above arrangement, the packaging barrier layer 20 can satisfy the lamination and composite processing technology.

For example, the packaging barrier layer 20 has a total thickness of 23 to 27 microns.

Table 1 gives some examples of barrier layers for packaging. Table 2 shows the performance test results of each example.

Table 1

Table 2

In the embodiments of the present disclosure, for the test methods of oxygen permeability and moisture permeability, please refer to the ISO international standard ISO15105-2:2003 "A test method for measuring any type of film, sheet, laminate, co-extruded material or flexible plastic coating material". "Method for Gas Transmission Rate of Plastic Materials" test methods and test conditions. For the testing methods of surface wetting tension, tensile strength, and elongation at break, please refer to the measurement methods and measurement conditions recorded in the Chinese national standard GB/T1040.3-2006.

4A is a DSC curve of the packaging barrier layer of Example 1 of the present disclosure; FIG. 4B is a DSC curve of the packaging barrier layer of Example 3 of the present disclosure.

As can be seen from Figure 4A, the base layer mixture of the barrier layer of Example 1 includes HDPE and LDPE, which accordingly has two melting point peaks of 109.33°C and 125.15°C. It can be seen from Figure 4B that the base layer mixture of the barrier layer of Example 3 includes HDPE, LDPE and LLDPE, which accordingly has three melting point peaks, which are 111.1°C, 122.8°C and 125.5°C respectively.

Differential scanning calorimetry (DSC) involved in this disclosure was performed in accordance with the German standard DIN EN ISO11357-1:2010-03. In this method, heat flow is measured as a function of temperature. Therefore, the ordinate axis in the figure is heat flow (dQ/dt), and the abscissa axis is temperature (T). The heat absorption direction is always upward, as in Note 2 to Part 3.1 of DIN EN ISO 11357-1:2010-03. Heat flow differential calorimetry was performed according to section 4.2 of the standard DIN EN ISO 11357 1:2010-03. In this case, the reference crucible is always empty and, according to section 3.10 of DIN EN ISO 11357-1:2010-03, the reference position is always used for the temperature. The flushing gas used is nitrogen (sections 5.5 and 9.1.2 of DIN EN ISO 11357 1:2010-03). Before each measurement, use calibration substances (DIN EN ISO 11357-1:2010-03, sections 3.2 and 5.4) indium and zinc (according to DIN Appendix C) of EN ISO 11357-1:2010-03) to calibrate DSC instruments. Thermal calibration is carried out using indium as calibration substance as recommended in 8.4.2 of DIN EN ISO 11357-1:2010-03. Measurements are carried out in dynamic mode (according to DIN EN ISO 11357-1:2010-03 section 3.9.5). In this case, the sample is usually preconditioned by a first heating from 30°C to 160°C at 5°C/min and maintaining this temperature for ten minutes. The sample was then cooled to 30°C at 5°C/min and then held at 30°C for 5 minutes. Then, the measurement process was carried out to 160°C at a heating rate of 5°C/min. Only the second heating curve described above was used for the evaluation of this measurement. The terms "peak" or "melting point peak" used in this article may be equivalent to the same terms used in DIN EN ISO 11357-1:2010-03. Therefore, the definition in section 3.9 of the standard is also valid.

As shown in FIG. 3 , for example, the packaging sheet composite layer further includes a light-shielding layer 50 located between the packaging barrier layer 20 and the carrier layer 30 for blocking light from entering the packaging container.

FIG. 5 is a schematic cross-sectional view of the light shielding layer according to an embodiment of the present disclosure. For example, the light-shielding layer 50 includes a base layer 501 and a light-shielding material 502 . The base layer 501 mainly includes polyolefin material, such as polyethylene. The light-shielding material 502 is added to the matrix 501 to improve the light-shielding effect of the sheet-like composite layer for packaging. The light-shielding material 502 includes color masterbatch, and the color masterbatch may include at least one of white masterbatch, black masterbatch, and gray masterbatch.

As shown in Figure 3, for example, the packaging sheet composite layer also includes a first adhesive layer 61 located between the inner covering layer 10 and the packaging barrier layer 20 to strengthen the relationship between the inner covering layer 10 and the packaging barrier layer 20. the bonding strength.

As shown in Figure 3, for another example, the packaging sheet composite layer further includes a second adhesive layer 62 located between the packaging barrier layer 20 and the light-shielding layer 50 to enhance the bonding between the packaging barrier layer 20 and the light-shielding layer 50. Bond strength.

For example, the first adhesive layer 61 and the second adhesive layer 62 may be selected to be suitable for use as adhesives in the art. Polymers of materials suitable for generating strong bonds by functionalization with the aid of suitable functional groups and by forming ionic or covalent bonds with the surfaces of corresponding adjacent layers. Preferably, polymers suitable for use as adhesive materials include functionalized polyolefins. Among these functionalized polyolefins, polyethylene-maleic anhydride graft polymer (EMAH), ethylene-acrylic acid copolymer (EAA) or ethylene-methacrylic acid copolymer are preferred. substance (Ethylene Methacrylic Acid, EMAA).

Another embodiment of the present disclosure provides a packaging container, which is folded from the packaging sheet composite layer described in the previous embodiment.

In the packaging container provided by the above embodiment, since the packaging barrier layer of the packaging sheet-shaped composite layer package has at least two melting point peaks, when the packaging container is sealed, the first base layer polymerizes due to the difference in melting point peaks. One of the polymers in the polymer and the second matrix layer enters the molten state first, and the other enters the molten state later. That is, as the temperature increases during sealing, the base layer polymer with a lower melting point peak enters the molten state first, and then the base layer polymer with a higher melting point peak enters the molten state. As a result, the layer structure of the barrier layer is prevented from undergoing rapid deformation due to temperature changes, and therefore the blistering phenomenon of the barrier layer under high-temperature heating conditions (for example, 300° C. to 400° C.) is avoided, thereby ensuring that the barrier layer with the present application The barrier layer packaging material provided can complete the heat sealing process under a wider temperature window (ie, a wider temperature range) when filling and sealing. At the same time, the use of two different base layer polymers ensures the stiffness and tensile strength of the barrier layer film, so that the barrier layer of this application can meet the process strength requirements of the composite production line.

Yet another embodiment of the present disclosure provides a packaging sheet composite layer, including a packaging barrier layer and an inner cover layered sequentially in a direction from the outer surface of the packaging sheet composite layer to the inner surface of the packaging sheet composite layer. layer. The inner covering layer mainly includes a plurality of inner covering layer polymers, and the plurality of inner covering layer polymers are all polyolefin materials and are different from each other. The plurality of inner covering layer polymers include a first inner covering layer polymer, and the mass percentage of the first inner covering layer polymer in the inner covering layer is more than 35%.

In the sheet-like composite layer for packaging provided in the above embodiment, by setting the mass percentage of the first inner covering layer polymer in the inner covering layer 10 to more than 35%, the risk of packaging container leakage (such as liquid leakage) can be reduced. risk.

In the embodiment of the present disclosure, the mass percentage can also be understood as the weight percentage, because G=mg, g is the proportional coefficient, and the gravity G increases with the increase of the mass m. In the embodiment of the present disclosure, substance A includes substance B, then "the mass percentage of substance B in substance A" can also be understood as "the weight percentage of substance B in substance A."

In the field of film products, gram weight is usually used as a technical indicator to measure weight or quality. Its international unit is "grams per square meter" (g/m ² ), abbreviated as FAW, which represents the number of grams of film per square meter. In the embodiment of the present disclosure, "the mass percentage of substance B in substance A" or "the weight percentage of substance B in substance A" refers to the mass percentage of the gram weight of substance B in the gram weight of substance A.

As shown in Figure 3, for example, the sheet-like composite layer for packaging provided in this embodiment does not include any metal layer. In known packaging containers, metal materials such as aluminum foil are usually used as packaging barrier layers to block water vapor or oxygen. However, the sheet-like composite layer for packaging provided by the embodiments of the present disclosure does not include any metal layer, that is, it does not include any metal element or alloy. Therefore, compared with sheet-like composite layers for packaging using metal materials, it is conducive to the recycling and reuse of packaging containers, reducing or even eliminating damage to the environment.

As shown in FIG. 3 , for example, a packaging sheet composite layer provided by yet another embodiment of the present disclosure includes a packaging barrier layer 20 and an inner covering layer 10 that are stacked sequentially along the Z direction. The inner covering layer 10 mainly includes a plurality of inner covering layer polymers, and the plurality of inner covering layer polymers are all polyolefin materials and are different from each other. In the embodiment of this disclosure, "multiple" means two or more.

For example, the inner cover layer 10 may include two or more inner cover layer polymers, and the inner cover layer polymers are polyolefin materials. For example, the inner cover polymer is one of a high density polyolefin, a low density polyolefin, and a metallocene polyolefin. Preferably, the polyolefin is polyethylene. For example, the inner cover polymer is one of high-density polyethylene (HDPE), low-density polyethylene (LDPE), and metallocene polyethylene (mPE).

In some embodiments, the mass percentage of the first inner covering layer polymer in the inner covering layer 10 is 35%, 37.5, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% , 80%, 85%, 90%, 95% or 100%. The higher the proportion of the first inner covering layer polymer in the inner covering layer 10 , the better. Since the first inner covering layer has better heat absorption properties, it can provide a wider heat sealing working window.

Further, for example, the mass percentage of the first inner covering layer polymer in the inner covering layer 10 is more than 40%. This can further reduce the risk of packaging containers leaking. Preferably, the mass percentage of the first inner covering layer polymer in the inner covering layer 10 is 37.5% to 50%, more preferably 45%. In some embodiments, the first inner cover polymer is a metallocene polyolefin. The metallocene polyolefin is, for example, metallocene polyethylene mPE.

Compared with high-density polyethylene HDPE and low-density polyethylene LDPE, metallocene polyethylene mPE film has a lower melting point and obvious melting zone, and has obvious improvements in toughness, transparency, hot tack, heat sealing temperature, and low odor. Superior to traditional polyethylene and therefore more suitable for flexible packaging film applications such as shrink wrap films for bottled water, beverages, canned goods, hand sanitizers, detergents, health and skin care products film or composite flexible packaging film. For example, metallocene polyethylene mPE includes linear low density polyethylene (LLDPE) and very low density polyethylene (VLDPE, density 0.90-0.915g/cm ³ ).

Figure 6 is a schematic cross-sectional view of the inner covering layer according to an embodiment of the present disclosure. As shown in FIG. 6 , the inner covering layer 10 includes a first inner layer 101 and a second inner layer 102 . The second inner layer 102 is laminated on the first inner layer 101 .

As mentioned in the previous embodiment, the function of the first adhesive layer 61 in FIG. 3 is to enhance the bonding strength between the inner cover layer 10 and the packaging barrier layer 20 . It can be understood that in other embodiments, the first adhesive layer 61 may not be provided between the two. Regardless of whether the first adhesive layer 61 is present, the second inner layer 102 can be regarded as being located between the first inner layer 101 and the packaging barrier layer 20 .

As shown in FIG. 6 , the second inner layer 102 is located on a side of the first inner layer 101 away from the inner surface of the packaging sheet composite layer.

For example, the first inner layer 101 includes a first side 101A and a second side 101B that are oppositely arranged in the Z direction. The first side 101A is close to the inner surface of the packaging sheet composite layer, and the second side 101B is close to the packaging sheet composite layer. the outer surface of the layer. The second inner layer 102 is located on the second side 101B.

For example, the first inner cover polymer includes a first portion distributed in the first inner layer 101 and a second portion distributed in the second inner layer 102 , the first portion of the first inner cover polymer being in the inner cover 10 The mass percentage of is greater than or equal to the mass percentage of the second part of the first inner covering layer polymer in the inner covering layer 10 .

In this embodiment, the first inner covering layer polymer is distributed in two layers (ie, the first inner layer 101 and the second inner layer 102), and the mass percentage of the first part of the first inner covering layer polymer is greater than It is equal to the mass percentage of the second part of the polymer of the first inner covering layer, which can prevent the packaging container from leaking. Since the heat absorption performance of the first inner covering layer is better, it can provide a wider heat sealing working window, so the heat The sealing effect is better.

In some embodiments, the first inner layer 101 and the second inner layer 102 may be in contact with each other, or may not be in contact with each other. For example, as shown in Figure 6, the first inner layer 101 and the second inner layer 102 are in contact with each other, and the mass percentage of the first portion of the first inner cover layer polymer in the first inner layer 101 is equal to the first inner cover layer polymer The mass percentage of the second part of the object in the second inner layer 102.

When the mass percentage of the first part of the first inner covering layer polymer in the first inner layer 101 is not equal to the mass percentage of the second part of the first inner covering layer polymer in the second inner layer 102, due to the need to Adjusting the weight of the polymer of the first inner covering layer by adjusting the weight of the first inner covering layer polymer with different component ratios in the inner layers will increase the difficulty in forming the first inner layer 101 or the second inner layer 102 .

In the above embodiment, by making the mass percentage of the first part of the first inner covering layer polymer in the first inner layer 101 equal to the mass percentage of the second part of the first inner covering layer polymer in the second inner layer 102, It can reduce the manufacturing difficulty and achieve better leak-proof package effect.

In some embodiments, the plurality of inner cover polymers further include a second inner cover polymer and a third inner cover polymer, each of the second inner cover polymer and the third inner cover polymer being different from the first Inner cover polymer. For example, when the first inner cover polymer is one of a high-density polyolefin, a low-density polyolefin, and a metallocene polyolefin, the second inner cover polymer and the third inner cover polymer are each a high-density polyolefin. The remaining two are polyolefins, low density polyolefins and metallocene polyolefins.

Further, when the first inner covering layer polymer is one of high density polyethylene HDPE, low density polyethylene LDPE and metallocene polyethylene mPE, the second inner covering layer polymer and the third inner covering layer polymer They are the remaining two types of high-density polyethylene HDPE, low-density polyethylene LDPE and metallocene polyethylene mPE. For example, when the first inner covering layer is mPE, the second inner covering layer polymer and the third inner covering layer polymer are LDPE and HDPE respectively.

Low-density polyethylene is a waxy white resin with a non-linear structure. Therefore, compared with medium density polyethylene and high density polyethylene, it has lower crystallinity and softening point, better flexibility, elongation, electrical insulation and higher impact strength. However, low-density polyethylene has poor mechanical strength and poor heat resistance.

Compared with low-density polyethylene, high-density polyethylene has better heat resistance and mechanical strength (such as tensile, bending, compression and shear strength) and improved barrier properties against water vapor and gas.

In the above embodiment, by providing the second inner covering layer polymer such as low density polyethylene and the third inner covering layer polymer such as high density polyethylene, the sheet-like composite layer for packaging can have better flexibility. , improve the heat resistance and mechanical strength of the inner covering layer on the premise of electrical insulation.

For example, the mass percentage of the mixture composed of the second inner covering layer polymer and the third inner covering layer polymer in the inner covering layer 10 is greater than or equal to the mass percentage of the first inner covering layer polymer in the inner covering layer 10 .

Compared with low-density polyethylene and high-density polyethylene, the material cost of metallocene polyethylene is higher. In the above embodiment, the mass percentage of the mixture composed of the second inner covering layer polymer and the third inner covering layer polymer in the inner covering layer 10 is greater than or equal to the mass percentage of the first inner covering layer polymer in the inner covering layer 10 The mass percentage can reduce the use of metallocene polyethylene materials on the premise of preventing packaging containers from leaking, thereby reducing product manufacturing costs.

In some embodiments, a blend of the second inner cover polymer and the third inner cover polymer is The compound includes a first part distributed in the first inner layer 101 and a second part distributed in the second inner layer 102, wherein the mass percentage of the first part of the mixture in the first inner layer 101 is equal to the mass percentage of the second part of the mixture in the second inner layer 102. The mass percentage of the second inner layer 102.

When the mass percentage of the first part of the mixture in the first inner layer 101 is not equal to the mass percentage of the second part of the mixture in the second inner layer 102, the mixture needs to be adjusted according to different component ratios in each inner layer. The weight will increase the difficulty in forming the first inner layer 101 or the second inner layer 102 .

In the above embodiment, by making the mass percentage of the first part of the mixture in the first inner layer 101 equal to the mass percentage of the second part of the mixture in the second inner layer 102, the manufacturing difficulty can be reduced while achieving better leakage prevention. package effect.

In the embodiment of the present disclosure, the mass percentage of the second inner covering layer polymer in the mixture and the mass percentage of the third inner covering layer polymer in the mixture may be equal or different. Those skilled in the art can choose according to actual needs. When the mass percentage of the second inner covering layer polymer in the mixture is equal to the mass percentage of the third inner covering layer polymer in the mixture, it is possible to avoid further adjustments when forming each inner layer and reduce the difficulty of the manufacturing process.

In some embodiments, the first inner layer is composed of a first portion of the first inner cover polymer and a first portion of the mixture, in which case the first portion of the first inner cover polymer is in the first inner layer 101 The mass percentage is 40% to 50%, and the mass percentage of the first part of the mixture in the first inner layer 101 is 50% to 60%.

Further, for example, the mass percentage of the first part of the first inner covering layer polymer in the first inner layer 101 is 40%, 45% or 50%; the mass percentage of the first part of the mixture in the first inner layer 101 is 50%, 55% or 60%.

In some embodiments, the second inner layer consists of a second portion of the first inner cover layer polymer and a second portion of the mixture, in which case the mass percent of the second portion of the mixture in the second inner layer is 50 % to 60%, and the mass percentage of the second part of the first inner covering layer polymer in the second inner layer is 40% to 50%.

Further, for example, the mass percentage of the second part of the first inner covering layer polymer in the first inner layer 101 is 40%, 45% or 50%; the mass percentage of the second part of the mixture in the first inner layer 101 The percentage is 50%, 55% or 60%.

Figure 7 is a schematic cross-sectional view of the inner covering layer according to another embodiment of the present disclosure. As shown in FIG. 7 , the inner covering layer 10 ′ includes a first inner layer 101 ′, a second inner layer 102 ′ and a third inner layer 103 . The second inner layer 102' and The third inner layer 103 is sequentially laminated on the first inner layer 101'.

As mentioned in the previous embodiment, the function of the first adhesive layer 61 in Figure 3 is to enhance the bonding strength between the inner cover layer 10' and the packaging barrier layer 20. It can be understood that in other embodiments, the first adhesive layer 61 may not be provided between the two. Regardless of whether the first adhesive layer 61 is present, the second inner layer 102' and the third inner layer 103 can be regarded as being located between the first inner layer 101' and the packaging barrier layer 20, and the third inner layer 103 is located between the first inner layer 101' and the packaging barrier layer 20. between the second inner layer 102' and the packaging barrier layer 20.

As shown in Figure 7, the second inner layer 102' is located on the side of the first inner layer 101' away from the inner surface of the packaging sheet composite layer, and the third inner layer 103 is located on the side of the second inner layer 102' away from the inner surface of the packaging sheet composite layer. One side of the inner surface of the sheet composite layer.

In some embodiments, the mixture further includes a third portion located in the third inner layer 103 . For example, the third inner layer 103 is composed of the third portion of the mixture, ie, the third inner layer 103 is composed of the second inner cover polymer and the third inner cover polymer.

Figure 8 is a schematic cross-sectional view of the inner covering layer according to yet another embodiment of the present disclosure. As shown in Figure 8, the inner covering layer 10" includes a first inner layer 101", a second inner layer 102" and a fourth inner layer 104. The second inner layer 102' and the third inner layer 103 are sequentially stacked on the first inner layer. On layer 101'.

As mentioned in the previous embodiment, the function of the first adhesive layer 61 in Figure 3 is to enhance the bonding strength between the inner covering layer 10" and the packaging barrier layer 20. It can be understood that in other embodiments, The first adhesive layer 61 may not be provided between the two. Regardless of whether there is the first adhesive layer 61, the second inner layer 102" and the fourth inner layer 104 can be regarded as being located in the first inner layer 101" and the packaging barrier layer 20, and the fourth inner layer 103 is located between the first inner layer 101" and the second inner layer 102".

As shown in Figure 8, the fourth inner layer 104 is located on the side of the first inner layer 101" away from the inner surface of the packaging sheet composite layer, and the second inner layer 102" is located on the side of the fourth inner layer 104 away from the packaging sheet. side of the inner surface of the composite layer.

For example, the first inner cover polymer includes a first portion distributed in the first inner layer 101 ″ and a second portion distributed in the second inner layer 102 ″ 102 , the first portion of the first inner cover polymer being in the first The mass percentage of the second portion of the first inner cover layer polymer in the inner second inner layer 102 ″ is greater than or equal to the mass percentage of the inner layer 101 ″.

In this embodiment, the first inner covering layer polymer is distributed in two layers (ie, the first inner layer 101 and the second inner layer 102), and the mass percentage of the first part of the first inner covering layer polymer is greater than It is equal to the mass percentage of the second part of the polymer of the first inner covering layer, which can prevent the packaging container from leaking. Since the heat absorption performance of the first inner covering layer is better, it can provide a wider heat sealing working window, so This heat sealing effect is better.

As shown in Figure 8, the first inner layer 101" and the second inner layer 102" do not contact each other. Since the first inner layer 101 ″ and the second inner layer 102 ″ are not in contact with each other, the mass percentage of the first portion of the first inner cover polymer in the inner cover 10 ″ may not be equal to the first portion of the first inner cover polymer. The mass percentage of the second part in the inner covering layer 10".

Compared to the case where the mass percentage of the first portion of the first inner cover polymer in the inner cover 10 ″ is equal to the mass percentage of the second portion of the first inner cover polymer in the inner cover 10 ″, this embodiment For example, the arrangement of the first inner layer 101 ″ and the second inner layer 102 ″ in the inner cover layer can be improved to facilitate the addition of other additional layers between the two, such as through a film layer that can increase the mechanical strength of the packaging material. Or a film layer that increases elongation and electrical insulation.

In some embodiments, the mass percentage of the first portion of the first inner cover polymer in the inner cover 10 ″ is greater than the mass percentage of the second portion of the first inner cover polymer in the inner cover 10 ″. For example, the first inner cover layer polymer is mPE, and by making the mass percentage of the portion of mPE contained in the first inner layer 101 ″ greater than the portion of mPE contained in the first inner layer 101 ″, The material on the side close to the inner surface of the packaging sheet composite layer has better toughness to further prevent the risk of package leakage.

In some embodiments, the plurality of inner cover polymers further include a second inner cover polymer and a third inner cover polymer, each of the second inner cover polymer and the third inner cover polymer being different from the first Inner cover polymer. The mixture consisting of the second inner cover layer polymer and the third inner cover layer polymer is distributed in at least one of the first inner layer 101" and the fourth inner layer 104. By distributing the above mixture in the first inner layer In at least one of the first inner layer 101" and the fourth inner layer 104, the first inner layer 101" or the fourth inner layer 104 can be improved on the premise of better flexibility and electrical insulation. Fourth inner layer for heat resistance and mechanical strength.

In this embodiment, regarding the specific materials of the first inner covering layer polymer, the second inner covering layer polymer, and the third inner covering layer polymer, please refer to the relevant descriptions in the previous embodiments and will not be described again here.

For example, the mixture may be distributed only in the first inner layer 101" and the fourth inner layer 104 is composed of one of the second inner cover polymer and the third inner cover polymer.

For another example, a part of the mixture is distributed in the first inner layer 101″, and another part of the mixture is distributed in the fourth inner layer 104.

In the embodiment of the present disclosure, when the melting point of the first adhesive layer 61 is 95-105°C, the sheet-like composite layer for packaging can better prevent package leakage.

The specific structure and material of the inner covering layer 10 will be further described below through specific examples. It can be understood that the materials and weights involved in the following examples are only illustrative and do not constitute a limitation on the present invention. In addition, each layer mentioned in the following examples may have the functions, structures, materials and parameters described in any previous embodiment.

Example 6:

9 is a schematic cross-sectional view of a laminated material of a sheet-like composite layer for packaging according to another embodiment of the present disclosure. As shown in Figure 9, for example, the sheet-like composite layer for packaging includes: outer covering layer 40, carrier layer 30, light-shielding layer 50, second adhesive layer 62, packaging barrier layer 20, first adhesive layer in order along the Z direction. Layer 61, second inner layer 102 and first inner layer 101.

Table 3 lists the grammage of each layer of Example 6.

table 3

In the packaging barrier layer 20, the base layer 200 is made of uniaxially stretched polyethylene MDOPE, the first barrier layer 201 is made of aluminum oxide AlOx, and the second barrier layer 202 is made of polyvinyl alcohol PVA.

The first inner layer 101 has a weight of 10g/m ² and is composed of 50% mPE and 50% MI7. mPE is metallocene polyethylene and MI7 is a mixture of low-density polyethylene LDPE and high-density polyethylene HDPE. That is, the gram weight of mPE in the first inner layer 101 is 5g/m ² , and the gram weight of the mixture of LDPE and HDPE is 5g/m ² .

The second inner layer 102 has a gram weight of 10g/m ² and a composition of 50% mPE and 50% MI7. That is, the gram weight of mPE in the second inner layer 102 is 5g/m ² , and the gram weight of the mixture of LDPE and HDPE is 5g/m ² .

The first adhesive layer 61 is M29, where M29 is ethylene-methane containing 3% to 9% methacrylic acid. acrylic copolymer. The peak melting point of M29 ranges from 95°C to 105°C, such as 100°C to 102°C.

As can be seen from Example 6, the total grammage of the inner covering layer 10 is 20g/m ² , and the total grammage of mPE in the first inner layer 101 and the second inner layer 102 is 10g/m ² . Therefore, the mPE is covered within The mass percentage of layer 10 is 50%.

The mPE in the first inner layer 101 (ie, the first portion of the first inner cover polymer) has the same grammage as the mPE in the second inner layer 102 (ie, the second portion of the first inner cover polymer), so The mass percentages of the two in the inner covering layer 10 are also the same, for example, both are 25%.

The first inner layer 101 and the second inner layer 102 are in contact with each other, and the mass percentage of mPE in the first inner layer 101 in the first inner layer 101 is equal to the mass percentage of mPE in the second inner layer 102 in the second inner layer 102 The mass percentage is, for example, 50%.

The total weight of MI7 in the first inner layer 101 and the second inner layer 102 is 10g/m ² , and the total weight of mPE in the first inner layer 101 and the second inner layer 102 is 10g/m ² . Therefore, MI7 is The mass percentage of mPE in the inner covering layer 10 is equal to the mass percentage of mPE in the inner covering layer 10 , for example, both are 50%.

The mass percentage of MI7 in the first inner layer 101 is equal to the mass percentage of MI7 in the second inner layer 102 , for example, both are 50%.

Example 7:

FIG. 10 is a schematic cross-sectional view of a laminated material of a sheet-like composite layer for packaging according to yet another embodiment of the present disclosure. As shown in Figure 10, for example, the sheet-like composite layer for packaging includes: outer covering layer 40, carrier layer 30, light-shielding layer 50, second adhesive layer 62, packaging barrier layer 20, first adhesive layer, along the Z direction. Layer 61, third inner layer 103, second inner layer 102' and first inner layer 101'.

Table 4 lists the grammage of each layer of Example 7.

Table 4

The first inner layer 101' has a weight of 10g/m ² and a composition of 45% mPE and 55% MI7. That is, the gram weight of mPE in the first inner layer 101 is 4.5g/m ² , and the gram weight of the mixture of LDPE and HDPE is 5.5 g/m ² .

The second inner layer 102' has a gram weight of 7g/m ² and a composition of 45% mPE and 55% MI7. That is, the gram weight of mPE in the second inner layer 102' is 3.15g/m ² and the gram weight of the mixture of LDPE and HDPE is 3.85 g/m ² .

The third inner layer 103 has a gram weight of 3g/m ² and a composition of MI7. That is, the third inner layer 103 is composed of a mixture of LDPE and HDPE.

It can be seen from Example 7 that the total gram weight of the inner covering layer 10' is 20g/m ² and the total gram weight of mPE in the first inner layer 101 and the second inner layer 102 is 7.65g/m ² . Therefore, the mPE is The mass percentage of the inner covering layer 10 is 38.2%.

The mPE in the first inner layer 101' (ie, the first part of the first inner covering layer polymer) has a gram weight of 45%*10g/m ² =4.5g/m ² , and the mPE in the second inner layer 102' ( That is, the grammage of the second part of the first inner covering layer polymer) is 55%*10g/m ² =5.5g/m ² . Therefore, the mPE in the first inner layer 101 ′ is in the inner covering layer 10 ′. The mass percentage is greater than the mass percentage of mPE in the second inner layer 102' in the inner cover layer 10'.

The first inner layer 101' and the second inner layer 102' are in contact with each other, and the mass percentage of mPE in the first inner layer 101' in the first inner layer 101' is equal to the mass percentage of mPE in the second inner layer 102' in the second inner layer 101'. The mass percentage in the inner layer 102' is, for example, 45%.

The total weight of MI7 in the first inner layer 101', the second inner layer 102' and the third inner layer is 5.5g/m ² +3.85g/m ² +3g/m ² =12.35g/m ² . The total weight of mPE in the inner layer 101' and the second inner layer 102' is 45%*10g/ ^m2 +45%*7g/ ^m2 =7.65g/ ^m2 . Therefore, MI7 is in the inner covering layer 10' The mass percentage is greater than the mass percentage of mPE in the inner covering layer 10'.

The mass percentage of MI7 in the first inner layer 101' is equal to the mass percentage of MI7 in the second inner layer 102', for example, both are 55%.

Example 8:

The sheet-like composite layer for packaging of Example 8 has the same laminate as the sheet-like composite layer for packaging of Fig. 10 structure. The difference from Example 6 is that the composition of the first inner layer 101' in Example 8 is 45% mPE and 55% MI7, the composition of the second inner layer 102' is 45% mPE and 55% MI7, and the second The weight of the inner layer 102' is 7g/m ² .

In Example 8, the total gram weight of the inner covering layer 10' is 17g/m ² and the total gram weight of mPE in the first inner layer 101' and the second inner layer 102' is 7.65g/m ^2. Therefore, mPE is included The mass percentage of the covering layer 10' is 45%.

Example 9:

The sheet-like composite layer for packaging in Example 9 has the same laminated structure as the sheet-like composite layer for packaging in FIG. 10 . The difference from Example 8 is that the first adhesive layer 61 in Example 9 is M28, where M28 is an ethylene-methacrylic acid copolymer containing more than 9% methacrylic acid. The peak melting point of M28 ranges from 95°C to 105°C, such as 100°C to 102°C.

The same as Example 8, the total gram weight of the inner covering layer 10' in Example 9 is 17g/m ² , and the total gram weight of the mPE in the first inner layer 101' and the second inner layer 102' is 7.65g/m ² , Therefore, the mass percentage of mPE in the inner cover layer 10' is 45%.

Example 10:

Figure 11 is a schematic cross-sectional view of a laminated material of a sheet-like composite layer for packaging provided by yet another embodiment of the present disclosure. As shown in Figure 11, for example, the sheet-like composite layer for packaging includes: an outer covering layer 40, a carrier layer 30, a light-shielding layer 50, a second adhesive layer 62, a packaging barrier layer 20, and a second inner layer along the Z direction. 102", the fourth inner layer 104 and the first inner layer 101".

Table 5 lists the grammage of each layer of Example 10.

table 5

The gram weight of the first inner layer 101" is 10g/m ² , and the composition is 45% mPE and 55% MI7, that is, the gram weight of mPE in the first inner layer 101" is 4.5g/m ² , LDPE and HDPE The weight of the mixture is 5.5g/m ² .

The weight of the second inner layer 102″ is 3g/m ² and its composition is mPE.

The fourth inner layer 104 has a gram weight of 7g/m ² and a composition of MI7.

It can be seen from Example 10 that the total grammage of the inner covering layer 10' is 20g/m ² and the total grammage of mPE in the first inner layer 101 and the second inner layer 102 is 7.5g/m ² . Therefore, the mPE is The mass percentage of the inner covering layer 10 is 37.5%.

The grammage of the mPE in the first inner layer 101 ″ (i.e., the first portion of the first inner cover polymer) is not equal to the mPE in the second inner layer 102 ″ (i.e., the second portion of the first inner cover polymer) The gram weight is different, so the mass percentage of the two in the inner covering layer 10" is different, that is, the former is greater than the latter.

The fourth inner layer 104 is located between the first inner layer 101 ″ and the second inner layer 102 ″, which are not in contact with each other.

The mass percentage of mPE in the first inner layer 101" in the first inner layer 101" is not equal to the mass percentage of mPE in the second inner layer 102" in the second inner layer 102", for example, the former is smaller than the latter.

The composition of the fourth inner layer 104 is MI7, so that MI7 is distributed in both the first inner layer 101" and the fourth inner layer 104. Further, the MI7 distributed in the first inner layer 101" and the MI7 in the fourth inner layer 104 The total gram weight of mPE is 55%*10g/m ² +7g/m ² =12.5g/m ² , and the total gram weight of mPE in the first inner layer 101" and the second inner layer 102" is 45%*10g/m ² +3g/m ² =7.5g/m ² . Therefore, in the inner covering layer, the total gram weight of MI7 is greater than the total gram weight of mPE, and the mass percentage of MI7 in the inner covering layer 10" is greater than the mass percentage of mPE in the inner covering layer 10".

Example 11:

The sheet-like composite layer for packaging in Example 11 has the same laminated structure as the sheet-like composite layer for packaging in FIG. 11 . The difference from Example 10 is that the second inner layer 102", the fourth inner layer 104 and the first inner layer 101" in Example 11 have different compositions and gram weights.

Table 6 lists the grammage of each layer of Example 11.

Table 6

The gram weight of the first inner layer 101" is 12g/m ² , and the composition is 45% mPE and 55% MI7, that is, the gram weight of mPE in the first inner layer 101" is 5.4g/m ² , LDPE and HDPE The weight of the mixture is 6.6g/m ² .

The fourth inner layer 104 has a weight of 5g/m ² and a composition of HDPE.

It can be seen from Example 10 that the total gram weight of the inner covering layer 10' is 20g/m ² and the total gram weight of mPE in the first inner layer 101 and the second inner layer 102 is 7.65g/m ² . Therefore, the mPE is The mass percentage of the inner covering layer 10 is 38.2%.

When the component of the fourth inner layer 104 is HDPE, it means that MI7 is distributed only in the first inner layer 101″.

Table 7 shows the packet leakage test results of Example 8 and Example 9 of the present disclosure. Before testing, the packaging sheet composite layers of Examples 8 and 9 were respectively formed into packaging containers. Then, add blue liquid to the packaging container and set aside.

After the packaging container is heated or placed to reach the corresponding test conditions, the blue liquid is removed from the packaging Pour it out of the container, open the packaging container, and observe the leakage of the blue liquid at the seal, and you will get the test results in Table 7.

Table 7

As can be seen from Table 7, Example 9 begins to leak packets when it exceeds 360°C, while Example 8 only starts to leak packets when it exceeds 390°C. Moreover, after being left for 1 hour, serious packet leakage occurred in Example 8. It can be seen from Table 7 that when the first adhesive used is M28, the occurrence of package leakage can be significantly reduced.

Through analysis, M28 has a slightly higher melting temperature than M29, with the former having a melting temperature of 101°C and the latter having a melting temperature of 100°C. Therefore, due to the high melting temperature of M28, package leakage is less likely to occur.

According to an embodiment of the present disclosure, there is also provided a sheet-like composite layer for packaging, comprising: packaging sequentially laminated in a direction from the outer surface of the packaging sheet-like composite layer to the inner surface of the packaging sheet-like composite layer. With a barrier layer; and an inner covering layer, the inner covering layer mainly includes a plurality of inner covering layer polymers, wherein the differential scanning calorimetry of the layer structure with the packaging barrier layer and the inner covering layer The graph includes peak _A at temperature TA and peak B at temperature _TB , which temperature _TB is greater than the temperature _TA .

In the embodiment of the present disclosure, the layer structure including the packaging barrier layer and the inner covering layer has the above two melting point peaks. When the packaging container is sealed, due to the difference in melting point peaks, one of the first base layer polymer and the second base layer polymer enters a molten state first, and the other enters a molten state later. That is, as the temperature increases during sealing, the base layer polymer with a lower melting point peak enters the molten state first, and then the base layer polymer with a higher melting point peak enters the molten state. In this way, the above layer structure is avoided to undergo rapid deformation due to temperature changes, thereby avoiding the phenomenon of blistering, thereby ensuring that the packaging material with the barrier layer provided by the present application can be filled and sealed in a relatively short time. The heat sealing process is completed under a wide temperature window (ie, a wider temperature range).

In some embodiments, the temperature _TA is at least 90°C. Further, for example, the temperature _TA is 90-110°C. In some embodiments, the temperature _TB is 120-140°C. Through the above settings, it is helpful to select a suitable polyolefin material to form the matrix layer mixture, which not only reduces the manufacturing cost, but also helps ensure the stiffness and tensile strength of the barrier layer film, so that the barrier layer can meet the process strength requirements of the composite production line.

In some embodiments, the characteristic of the peak A is the melting enthalpy H _A , the characteristic of the peak B is the melting enthalpy H _B , and the ratio of the melting enthalpy H _A to the melting enthalpy H _B ranges from 1:10 to 1: 5.

In some embodiments, the absolute value of the difference between the temperature _TB and the temperature _TA is at least 25°C. In some embodiments, the absolute value of the difference between the temperature _TB and the temperature _TA is no more than 40°C. Through the above settings, it is possible to further ensure that the barrier layer has two melting point peaks without changing the sealing temperature, thus avoiding the rapid deformation of the upper layer structure due to temperature changes.

In some embodiments, the packaging sheet composite layer includes an inner cover layer as described in any of the previous embodiments. Regarding the specific structure and materials of the inner covering layer, please refer to the descriptions in the previous embodiments and will not be repeated here.

Example 12

For example, referring to Figure 10, the sheet-like composite layer for packaging in Example 12 includes in the Z direction: an outer covering layer 40, a carrier layer 30, a light-shielding layer 50, a second adhesive layer 62, a packaging barrier layer 20, a first adhesive layer The composite layer 61, the third inner layer 103, the second inner layer 102' and the first inner layer 101'.

In the packaging barrier layer 20, the base layer mixture of the base layer 200 includes HDPE and LDPE, the first barrier layer 201 is aluminum oxide AlOx, and the second barrier layer 202 is polyvinyl alcohol PVA. The total weight of the packaging barrier layer 20 is 29.5g/m ² .

The first inner layer 101' has a weight of 9g/m ² and a composition of 50% mPE and 50% MI7.

The second inner layer 102' has a gram weight of 7g/m ² and a composition of 50% mPE and 50% MI7.

The third inner layer 103 has a gram weight of 6g/m ² and a composition of 50% mPE and 50% MI7.

The first adhesive layer 61 is mPE.

Figure 12 is a DSC graph of a layer structure consisting of an inner cover layer and a packaging barrier layer in Example 12 of the present disclosure. That is, the DSC curve obtained by taking the layer structure of (inner covering layer + packaging barrier layer) as the detection object. As can be seen from Figure 12, the DSC curve has two melting point peaks A and B, They are temperature _TA = 102.93°C and temperature _TB = 134.96°C respectively. Delta H represents the melting enthalpy. The two melting enthalpies H _A and H _B are 8.57J/g and 78.2J/g respectively.

Example 13

For example, referring to Figure 10, the packaging sheet composite layer of Example 13 includes in the Z direction: an outer covering layer 40, a carrier layer 30, a light-shielding layer 50, a second adhesive layer 62, a packaging barrier layer 20, a first adhesive layer The composite layer 61, the third inner layer 103, the second inner layer 102' and the first inner layer 101'.

In the packaging barrier layer 20, the base layer mixture of the base layer 200 includes HDPE and LDPE, the first barrier layer 201 is aluminum oxide AlOx, and the second barrier layer 202 is polyvinyl alcohol PVA. The total weight of the packaging barrier layer 20 is 24.5g/m ² .

The third inner layer 103' has a gram weight of 6g/m ² and a composition of 50% mPE and 50% MI7.

The first adhesive layer 61 is mPE.

Figure 13 is a DSC graph of a layer structure consisting of an inner cover layer and a packaging barrier layer in Example 13 of the present disclosure. That is, the DSC curve obtained by taking the layer structure of (inner covering layer + packaging barrier layer) as the detection object. As can be seen from Figure 13, the DSC curve has two melting point peaks A and B, which are temperature _TA = 102.91°C and temperature _TB = 134.68°C respectively. Delta H represents the melting enthalpy, and the two melting enthalpies H _A and H _B They are 9.07J/g and 65.52J/g respectively.

Example 14

For example, referring to FIG. 9 , the packaging sheet composite layer of Example 14 includes, along the Z direction, an outer covering layer 40 , a carrier layer 30 , a light-shielding layer 50 , a second adhesive layer 62 , a packaging barrier layer 20 , and a first adhesive layer. The composite layer 61, the second inner layer 102 and the first inner layer 101.

Table 8 lists the grammage of each layer of Example 13.

Table 8

The compositions of the first inner layer 101 and the second inner layer 102 are both 50% mPE and 50% MI7. The first adhesive layer 61 is M29.

14 is a DSC graph of a layer structure consisting of an inner cover layer and a packaging barrier layer in Example 14 of the present disclosure. That is, the DSC curve obtained by taking the layer structure of (inner covering layer + packaging barrier layer) as the detection object. As can be seen from Figure 14, the DSC curve has two melting point peaks A and B, which are temperatures _TA = 103.19°C and _TB = 131.65°C respectively. Delta H represents the melting enthalpy, and the two melting enthalpies H _A and H _B are respectively are 13.05J/g and 68.93J/g.

In the packaging barrier layer, the packaging sheet composite layer and the packaging container provided by the embodiments of the present disclosure, since the packaging barrier layer includes a base layer, the base layer mainly includes a base layer mixture, and the base layer mixture has at least two different The first base layer polymer and the second base layer polymer make the packaging barrier layer have at least two melting point peaks. On the one hand, when the packaging container is sealed, due to the presence of multiple melting point peaks, the first base layer polymer and the second base layer polymer can enter the molten state respectively. Compared with when the two polymers enter the molten state at the same time, The layer structure of the barrier layer will undergo sharp deformation. This application can avoid the above-mentioned deformation, thereby avoiding the occurrence of bubbles in the barrier layer. On the other hand, the use of two different base layer polymers ensures the stiffness and tensile strength of the barrier layer film, so that the barrier layer of the present application can meet the process strength requirements of the composite production line.

The barrier layer for packaging, the sheet-like composite layer for packaging, and the packaging container provided by the embodiments of the present disclosure do not include any metal material or metal layer. Compared with the barrier layer made of metal materials, it is conducive to the recycling and reuse of packaging containers, reducing or even eliminating damage to the environment.

In the sheet-like composite layer for packaging and its containing container provided by another embodiment of the present disclosure, by setting the mass percentage of the first inner covering layer polymer in the inner covering layer to more than 35%, leakage of the packaging container can be reduced ( such as leakage).

In addition, the present disclosure may also include the following embodiments or examples.

(1) A packaging barrier layer, wherein the packaging barrier layer does not include a metal layer, and the packaging barrier layer includes:

The base layer mainly includes a base layer mixture, the base layer mixture includes at least two base bodies layer polymer;

a first barrier layer stacked with the base layer and including a metal oxide;

Wherein, the at least two base layer polymers include a first base layer polymer and a second base layer polymer, and the first base layer polymer and the second base layer polymer are different, so that the packaging The barrier layer has at least two melting point peaks.

(2) The barrier layer for packaging according to (1), wherein the at least two melting point peaks include a first melting point peak and a second melting point peak, and there is a gap between the first melting point peak and the second melting point peak. The difference is 5℃～30℃.

(3) The packaging barrier layer according to (2), wherein the first melting point peak is lower than the second melting point peak,

The first melting point peak is 100°C to 130°C;

The second melting point peak is 120°C to 140°C.

(4) The packaging barrier layer according to any one of (1) to (3), wherein the base layer mixture further includes a third base layer polymer, and the third base layer polymer is different from the The first base layer polymer and the second base layer polymer are such that the packaging barrier layer has at least three melting point peaks.

(5) The packaging barrier layer according to (4), wherein:

The at least three melting point peaks include a first melting point peak, a second melting point peak and a third melting point peak, and the difference between the first melting point peak and the second melting point peak is 5°C to 30°C;

The difference between the second melting point peak and the third melting point peak is 2°C to 15°C.

(6) The packaging barrier layer according to (5), wherein the third melting point peak is higher than the first melting point peak and lower than the second melting point peak,

The first melting point peak is 100°C to 130°C;

The second melting point peak is 120°C to 140°C;

The third melting point peak ranges from 110°C to 125°C.

(7) The packaging barrier layer according to any one of (1) to (6), wherein the stretching ratio of the packaging barrier layer is 0 to 5.5.

(8) The packaging barrier layer according to (7), wherein the stretching ratio of the packaging barrier layer is 4.5 to 5.

(9) The packaging barrier layer according to any one of (1) to (8), wherein the oxygen permeability of the packaging barrier layer under a relative humidity condition of 70% is the same as that under a relative humidity condition of 50% of oxygen permeation The transmittance ratio is 2 to 10.

(10) The packaging barrier layer according to (9), wherein,

Under the condition of 50% relative humidity, the oxygen permeability of the packaging barrier layer ranges from 0.1 to 1.5cc/ ^m2 ·24 hours·atm; and

Under the condition of 70% relative humidity, the oxygen permeability of the packaging barrier layer ranges from 1 to 15 cc/m ² ·24 hours·atm.

(11) The packaging barrier layer according to any one of (1) to (10), wherein the ratio of the longitudinal tensile strength to the transverse tensile strength of the packaging barrier layer is 2 to 10.

(12) The packaging barrier layer according to (11), wherein,

The longitudinal tensile strength of the packaging barrier layer is 60-100Mpa;

The transverse tensile strength of the packaging barrier layer is 10-30Mpa.

(13) The packaging barrier layer according to any one of (1) to (12), wherein the ratio of the transverse elongation at break and the longitudinal elongation at break of the packaging barrier layer is 5 to 35.

(14) The packaging barrier layer according to (13), wherein,

The packaging barrier layer has a longitudinal elongation at break of 20% to 80%;

The packaging barrier layer has a transverse elongation at break of 100% to 700%.

(15) The packaging barrier layer according to any one of (1) to (14), further including:

A second barrier layer is located between the base layer and the first barrier layer, wherein the second barrier layer includes polyvinyl alcohol.

(16) The packaging barrier layer according to (15), wherein the total thickness of the packaging barrier layer is 23 to 27 microns.

(17) The packaging barrier layer according to any one of (1) to (16), wherein,

The first base layer polymer includes a first polyolefin material;

The second base layer polymer includes a second polyolefin material;

The first polyolefin material and the second polyolefin material are different from each other such that the packaging barrier layer has the at least two melting point peaks.

(18) The barrier layer for packaging according to (17),

Wherein, the base layer mixture further includes a third base layer polymer, and the third base layer polymer includes a third polyolefin material;

The third polyolefin material is different from the first polyolefin material and the second polyolefin material such that the packaging barrier layer has at least three melting point peaks.

(19) The packaging barrier layer according to (18), wherein,

The first polyolefin material is one of high density polyethylene, medium density polyethylene, and low density polyethylene;

The second polyolefin material is one of high density polyethylene, medium density polyethylene, and low density polyethylene;

The third polyolefin material is low density linear polyethylene.

(20) A sheet-like composite layer for packaging, comprising: stacked sequentially in the direction from the outer surface of the packaging sheet-like composite layer to the inner surface of the packaging sheet-like composite layer:

outer covering;

carrier layer;

A barrier layer for packaging according to any one of (1) to (19); and

Inner covering.

(21) A packaging container formed by folding the sheet-like composite layer for packaging described in (20).

(22) A sheet-like composite layer for packaging, comprising: stacked sequentially in the direction from the outer surface of the packaging sheet-like composite layer to the inner surface of the packaging sheet-like composite layer:

Barrier layers for packaging; and

The inner covering layer mainly includes a plurality of inner covering layer polymers, and the plurality of inner covering layer polymers are all polyolefin materials and different from each other,

Wherein, the plurality of inner covering layer polymers include a first inner covering layer polymer, and the mass percentage of the first inner covering layer polymer in the inner covering layer is more than 35%.

(23) The sheet-like composite layer for packaging according to (22),

Wherein, the inner covering layer includes:

first inner layer; and

a second inner layer located between the first inner layer and the packaging barrier layer;

wherein a first portion of the first inner covering layer polymer is distributed in the first inner layer, and a second portion of the first inner covering layer polymer is distributed in the second inner layer,

Wherein, the mass percentage of the sum of the first part and the second part of the first inner covering layer polymer in the inner covering layer is more than 40%.

(24) The sheet-like composite layer for packaging according to (23),

Wherein, the mass percentage of the first part of the first inner covering layer polymer in the inner covering layer is greater than or equal to the mass percentage of the second part of the first inner covering layer polymer in the inner covering layer. mass percentage in.

(25) The sheet-like composite layer for packaging according to (24),

Wherein, the first inner layer and the second inner layer are in contact with each other, and the mass percentage of the first portion of the first inner cover layer polymer in the first inner layer is equal to the first inner layer. The mass percentage of the second portion of cover layer polymer in the second inner layer.

(26) The sheet-like composite layer for packaging according to (25),

Wherein, the plurality of inner covering layer polymers further include a second inner covering layer polymer and a third inner covering layer polymer, and the second inner covering layer polymer and the third inner covering layer polymer are different In the first inner covering layer polymer,

Wherein, the mass percentage of the mixture composed of the second inner covering layer polymer and the third inner covering layer polymer in the inner covering layer is greater than or equal to that of the first inner covering layer polymer in the inner covering layer. The mass percentage in the covering layer.

(27) The sheet-like composite layer for packaging according to (26),

wherein a first portion of the mixture is distributed in the first inner layer, and a second portion of the mixture is distributed in the second inner layer,

Wherein, the mass percentage of the first part of the mixture in the first inner layer is equal to the mass percentage of the second part of the mixture in the second inner layer.

(28) The sheet-like composite layer for packaging according to (27), wherein:

The mass percentage of the first part of the first inner covering layer polymer in the first inner layer is 40% to 50%, and the mass percentage of the first part of the mixture in the first inner layer The percentage is 50% to 60%; and

The mass percentage of the second part of the mixture in the second inner layer is 50% to 60%, and the second part of the first inner covering layer polymer is in the second inner layer The mass percentage is 40% to 50%.

(29) The sheet-like composite layer for packaging according to (27),

Wherein, the inner covering layer also includes:

A third inner layer located between the second inner layer and the packaging barrier layer,

Wherein the third inner layer consists of a third portion of the mixture.

(30) The sheet-like composite layer for packaging according to (23),

Wherein, the first inner layer and the second inner layer do not contact each other, and the mass percentage of the first portion of the first inner cover layer polymer in the first inner layer is less than the first inner coverage The mass percent of said second portion of layer polymer in said second inner layer.

(31) The sheet-like composite layer for packaging according to (30),

Wherein, the inner covering layer also includes:

a fourth inner layer located between the first inner layer and the second inner layer,

Wherein, a mixture composed of the second inner cover layer polymer and the third inner cover layer polymer is distributed in at least one of the first inner layer and the fourth inner layer.

(32) The sheet-like composite layer for packaging according to (31),

Wherein, the mixture is only distributed in the first inner layer, and the fourth inner layer is composed of one of the second inner covering layer polymer and the third inner covering layer polymer.

(33) The sheet-like composite layer for packaging according to (31),

Wherein, a part of the mixture is distributed in the first inner layer, and another part of the mixture is distributed in the fourth inner layer.

(34) The sheet-like composite layer for packaging according to (26), wherein:

The first inner covering layer polymer is metallocene polyethylene;

The second inner covering layer polymer is high density polyethylene;

The third inner covering layer polymer is low density polyethylene.

(35) The sheet-like composite layer for packaging according to any one of (22) to (34), further comprising:

A first adhesive layer is located between the packaging barrier layer and the inner cover layer, wherein the melting point of the first adhesive layer is 95°C to 105°C.

(36) A packaging container formed by folding the sheet-like composite layer for packaging according to any one of (22) to (35).

(37) A sheet-like composite layer for packaging, comprising: stacked sequentially in the direction from the outer surface of the packaging sheet-like composite layer to the inner surface of the packaging sheet-like composite layer:

Barrier layers for packaging; and

an inner covering layer, the inner covering layer mainly includes a plurality of inner covering layer polymers,

Wherein, the differential scanning calorimetry curve of the layer structure with the packaging barrier layer and the inner cover layer includes peak A at temperature T _A and peak B at temperature T _B , and the temperature T _B is greater than the temperature _TA .

(38) The sheet-like composite layer for packaging according to (37), wherein the temperature _TA is at least 90°C.

(39) The sheet-like composite layer for packaging according to (38), wherein the temperature _TA is 90-110°C.

(40) The sheet-like composite layer for packaging according to (37), wherein the temperature _TB is 120-140°C.

(41) The sheet-like composite layer for packaging according to (37), wherein the characteristic of the peak A is the melting enthalpy H _A , the characteristic of the peak B is the melting enthalpy H _B , and the melting enthalpy H _{A is related to the melting enthalpy H A} The ratio of enthalpy H _B ranges from 1:10 to 1:5.

(42) The sheet-like composite layer for packaging according to (37), wherein the absolute value of the difference between the temperature _TB and the temperature _TA is at least 25°C.

(43) The sheet-like composite layer for packaging according to (42), wherein the absolute value of the difference between the temperature _TB and the temperature _TA is not more than 40°C.

(44) The sheet-like composite layer for packaging according to (37), wherein the inner covering layer mainly includes a plurality of inner covering layer polymers, and the plurality of inner covering layer polymers are all polyolefin materials and mutually exclusive. Differently, the plurality of inner covering layer polymers include a first inner covering layer polymer, and the mass percentage of the first inner covering layer polymer in the inner covering layer is more than 35%.

(45). The sheet-like composite layer for packaging according to claim (44), including the inner covering layer according to any one of claims (23) to (29), (34), and (35).

In this article, there are the following points to note:

(1) The drawings of the embodiments of this disclosure only refer to structures related to the embodiments of this disclosure, and other structures may refer to common designs.

(2) Without conflict, the embodiments of the present disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

The above descriptions are only exemplary embodiments of the present disclosure and are not used to limit the scope of the present disclosure, which is determined by the appended claims.

Claims

A packaging barrier layer, wherein the packaging barrier layer does not include a metal layer, and the packaging barrier layer includes:

The base layer mainly includes a base layer mixture, and the base layer mixture includes at least two base layer polymers;

a first barrier layer stacked with the base layer and including a metal oxide;

Wherein, the at least two base layer polymers include a first base layer polymer and a second base layer polymer, and the first base layer polymer and the second base layer polymer are different, so that the packaging The barrier layer has at least two melting point peaks.
The barrier layer for packaging according to claim 1, wherein the at least two melting point peaks comprise a first melting point peak and a second melting point peak, and the difference between the first melting point peak and the second melting point peak 5℃～30℃.
The packaging barrier layer of claim 2, wherein the first melting point peak is lower than the second melting point peak,

The first melting point peak is 100°C to 130°C;

The second melting point peak is 120°C to 140°C.
The packaging barrier layer according to any one of claims 1 to 3, wherein the base layer mixture further includes a third base layer polymer, the third base layer polymer being different from the first base layer polymer. and the polymer of the second base layer, so that the packaging barrier layer has at least three melting point peaks.
The packaging barrier layer according to claim 4, wherein:

The at least three melting point peaks include a first melting point peak, a second melting point peak and a third melting point peak, and the difference between the first melting point peak and the second melting point peak is 5°C to 30°C;

The difference between the second melting point peak and the third melting point peak is 2°C to 15°C.
The packaging barrier layer of claim 5, wherein the third melting point peak is higher than the first melting point peak and lower than the second melting point peak,

The first melting point peak is 100°C to 130°C;

The second melting point peak is 120°C to 140°C;

The third melting point peak ranges from 110°C to 125°C.
The packaging barrier layer according to any one of claims 1 to 6, wherein the packaging barrier layer The stretch ratio of the interlayer is 0 to 5.5.
The packaging barrier layer according to claim 7, wherein the stretching ratio of the packaging barrier layer is 4.5 to 5.
The packaging barrier layer according to any one of claims 1 to 8, wherein the oxygen permeability of the packaging barrier layer under a relative humidity condition of 70% is equal to the oxygen permeability under a relative humidity condition of 50%. The ratio is 2 to 10.
The packaging barrier layer according to claim 9, wherein

Under the condition of 50% relative humidity, the oxygen permeability of the packaging barrier layer ranges from 0.1 to 1.5cc/ m2 ·24 hours·atm; and

Under the condition of 70% relative humidity, the oxygen permeability of the packaging barrier layer ranges from 1 to 15 cc/m 2 ·24 hours·atm.
The packaging barrier layer according to any one of claims 1 to 10, wherein the ratio of the longitudinal tensile strength to the transverse tensile strength of the packaging barrier layer is 2 to 10.
The packaging barrier layer according to claim 11, wherein

The longitudinal tensile strength of the packaging barrier layer is 60-100Mpa;

The transverse tensile strength of the packaging barrier layer is 10-30Mpa.
The packaging barrier layer according to any one of claims 1 to 12, wherein the ratio of the transverse elongation at break and the longitudinal elongation at break of the packaging barrier layer is 5 to 35.
The packaging barrier layer according to claim 13, wherein

The packaging barrier layer has a longitudinal elongation at break of 20% to 80%;

The packaging barrier layer has a transverse elongation at break of 100% to 700%.
The packaging barrier layer according to any one of claims 1 to 14, further comprising:

A second barrier layer is located between the base layer and the first barrier layer, wherein the second barrier layer includes polyvinyl alcohol.
The packaging barrier layer according to claim 15, wherein the total thickness of the packaging barrier layer is 23 to 27 microns.
The packaging barrier layer according to any one of claims 1 to 16, wherein,

The first base layer polymer includes a first polyolefin material;

The second base layer polymer includes a second polyolefin material;

The first polyolefin material and the second polyolefin material are different from each other such that the packaging barrier layer has the at least two melting point peaks.
The barrier layer for packaging according to claim 17,

Wherein, the base layer mixture further includes a third base layer polymer, and the third base layer polymer includes a third polyolefin material;

The third polyolefin material is different from the first polyolefin material and the second polyolefin material such that the packaging barrier layer has at least three melting point peaks.
The packaging barrier layer according to claim 18, wherein

The first polyolefin material is one of high density polyethylene, medium density polyethylene, and low density polyethylene;

The second polyolefin material is one of high density polyethylene, medium density polyethylene, and low density polyethylene;

The third polyolefin material is low density linear polyethylene.
A sheet-like composite layer for packaging, including layers laminated in sequence from the outer surface of the packaging sheet-like composite layer to the inner surface of the packaging sheet-like composite layer:

outer covering;

carrier layer;

The packaging barrier layer according to any one of claims 1 to 19; and

Inner covering.
A packaging container formed by folding the sheet-like composite layer for packaging according to claim 20.
A sheet-like composite layer for packaging, including layers laminated in sequence from the outer surface of the packaging sheet-like composite layer to the inner surface of the packaging sheet-like composite layer:

Barrier layers for packaging; and

The inner covering layer mainly includes a plurality of inner covering layer polymers, and the plurality of inner covering layer polymers are all polyolefin materials and different from each other,

Wherein, the plurality of inner covering layer polymers include a first inner covering layer polymer, and the mass percentage of the first inner covering layer polymer in the inner covering layer is more than 35%.
The sheet-like composite layer for packaging according to claim 22,

Wherein, the inner covering layer includes:

first inner layer; and

a second inner layer located between the first inner layer and the packaging barrier layer;

wherein a first portion of the first inner covering layer polymer is distributed in the first inner layer, and a second portion of the first inner covering layer polymer is distributed in the second inner layer,

Wherein, the mass percentage of the sum of the first part and the second part of the first inner covering layer polymer in the inner covering layer is more than 40%.
The sheet-like composite layer for packaging according to claim 23,

Wherein, the mass percentage of the first part of the first inner covering layer polymer in the inner covering layer is greater than or equal to the mass percentage of the second part of the first inner covering layer polymer in the inner covering layer mass percentage.
The sheet-like composite layer for packaging according to claim 24,

Wherein, the first inner layer and the second inner layer are in contact with each other, and the mass percentage of the first portion of the first inner cover layer polymer in the first inner layer is equal to the first inner layer. The mass percentage of the second portion of cover layer polymer in the second inner layer.
The sheet-like composite layer for packaging according to claim 25,

Wherein, the plurality of inner covering layer polymers further include a second inner covering layer polymer and a third inner covering layer polymer, and the second inner covering layer polymer and the third inner covering layer polymer are different In the first inner covering layer polymer,

Wherein, the mass percentage of the mixture composed of the second inner covering layer polymer and the third inner covering layer polymer in the inner covering layer is greater than or equal to that of the first inner covering layer polymer in the inner covering layer. The mass percentage in the covering layer.
The sheet-like composite layer for packaging according to claim 26,

wherein a first portion of the mixture is distributed in the first inner layer, and a second portion of the mixture is distributed in the second inner layer,

Wherein, the mass percentage of the first part of the mixture in the first inner layer is equal to the mass percentage of the second part of the mixture in the second inner layer.
The sheet-like composite layer for packaging according to claim 27, wherein:

The mass percentage of the first part of the first inner covering layer polymer in the first inner layer is 40% to 50%, and the mass percentage of the first part of the mixture in the first inner layer The percentage is 50% to 60%; and

The mass percentage of the second part of the mixture in the second inner layer is 50% to 60%, and the second part of the first inner covering layer polymer is in the second inner layer The mass percentage is 40% to 50%.
The sheet-like composite layer for packaging according to claim 27,

Wherein, the inner covering layer also includes:

A third inner layer located between the second inner layer and the packaging barrier layer,

Wherein the third inner layer consists of a third portion of the mixture.
The sheet-like composite layer for packaging according to claim 23,

Wherein, the first inner layer and the second inner layer do not contact each other, and the mass percentage of the first portion of the first inner cover layer polymer in the first inner layer is less than the first The mass percentage of the second portion of the inner cover polymer in the second inner layer.
The sheet-like composite layer for packaging according to claim 30,

Wherein, the inner covering layer also includes:

a fourth inner layer located between the first inner layer and the second inner layer,

Wherein, the plurality of inner covering layer polymers further include a second inner covering layer polymer and a third inner covering layer polymer, and the second inner covering layer polymer and the third inner covering layer polymer are different In the first inner covering layer polymer,

Wherein, a mixture composed of the second inner cover layer polymer and the third inner cover layer polymer is distributed in at least one of the first inner layer and the fourth inner layer.
The sheet-like composite layer for packaging according to claim 31,

Wherein, the mixture is only distributed in the first inner layer, and the fourth inner layer is composed of one of the second inner covering layer polymer and the third inner covering layer polymer.
The sheet-like composite layer for packaging according to claim 31,

Wherein, a part of the mixture is distributed in the first inner layer, and another part of the mixture is distributed in the fourth inner layer.
The sheet-like composite layer for packaging according to claim 26, wherein:

The first inner covering layer polymer is metallocene polyethylene;

The second inner covering layer polymer is high density polyethylene;

The third inner covering layer polymer is low density polyethylene.
The sheet-like composite layer for packaging according to any one of claims 22 to 34, further comprising:

A first adhesive layer is located between the packaging barrier layer and the inner cover layer, wherein the melting point of the first adhesive layer is 95°C to 105°C.
A packaging container formed by folding the sheet-like composite layer for packaging according to any one of claims 22 to 35.
A sheet-like composite layer for packaging, including layers laminated in sequence from the outer surface of the packaging sheet-like composite layer to the inner surface of the packaging sheet-like composite layer:

Barrier layers for packaging; and

an inner covering layer, the inner covering layer mainly includes a plurality of inner covering layer polymers,

Wherein, the differential scanning calorimetry curve of the layer structure with the packaging barrier layer and the inner cover layer includes peak A at temperature T A and peak B at temperature T B , and the temperature T B is greater than the temperature TA .
The sheet-like composite layer for packaging according to claim 37, wherein the temperature TA is at least 90°C.
The sheet-like composite layer for packaging according to claim 38, wherein the temperature TA is 90-110°C.
The sheet-like composite layer for packaging according to claim 37, wherein the temperature TB is 120-140°C.
The sheet composite layer for packaging according to claim 37, wherein the characteristic of peak A is melting enthalpy H A , the characteristic of peak B is melting enthalpy HB , the melting enthalpy H A and the melting enthalpy H B The ratio range is 1:10 to 1:5.
The sheet-like composite layer for packaging according to claim 37, wherein the absolute value of the difference between the temperature TB and the temperature TA is at least 25°C.
The sheet-like composite layer for packaging according to claim 42, wherein the absolute value of the difference between the temperature TB and the temperature TA is no more than 40°C.
The sheet-like composite layer for packaging according to claim 37, wherein the inner covering layer mainly includes a plurality of inner covering layer polymers, and the plurality of inner covering layer polymers are polyolefin materials and are different from each other, wherein , the plurality of inner covering layer polymers include a first inner covering layer polymer, and the mass percentage of the first inner covering layer polymer in the inner covering layer is more than 35%.
The sheet-like composite layer for packaging according to claim 44, including the inner cover layer according to any one of claims 23 to 29, 34, and 35.