Low-temperature PE heat-sealing film applied to BOPE / PE single material and preparation method of low-temperature PE heat-sealing film

Abstract

The low-temperature PE heat-sealing film applied to the BOPE / PE single material and the preparation method are further provided, the low-temperature PE heat-sealing film comprises a heat-sealing layer, a core layer and a corona layer, the heat-sealing layer is formed by optimally combining materials such as metallocene polyethylene, a butylene-octene copolymer and low-density polyethylene, a polymer processing aid, an anti-blocking agent and a slipping agent are added, and the corona layer is formed by a corona layer and a corona layer, so that the low-temperature PE heat-sealing film applied to the BOPE / PE single material is obtained. The heat sealing performance is optimized; the corona layer and the core layer are made of high-density polyethylene, linear low-density polyethylene and other materials, an anti-reflection nucleating agent and other auxiliaries are added, the heat resistance and stiffness of the corona layer and the core layer are optimized, a certain softening point temperature gradient is formed among the corona layer, the core layer and the heat sealing layer, and the relation between the heat sealing performance and the tensile property is balanced. According to the low-temperature PE heat-sealing film applied to the BOPE / PE single material, the heat-sealing temperature gradient of BOPE is 30 DEG C or above, the heat resistance of the three-layer structure of the heat-sealing layer, the core layer and the corona layer is also increased in a gradient mode, and the heat-sealing strength is larger than 10 N / 15 mm.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material preparation, and particularly relates to a low-temperature PE heat-sealing film applied to BOPE / PE single material and a preparation method thereof. Background Art

[0002] The composite film materials of domestic soft packaging companies are basically composites of films of various different materials, such as PA / PE, BOPP / VMPET / PE, VMPET / CPP, PET / AL / PE and other structures. Different composite film materials have their own unique functionality, such as providing stretch film layers for printing and mechanical strength, providing metal aluminum foil layers for ultra-high barrier, providing polyolefin film layers for heat sealing, providing paper layers for high stiffness, etc. The recycling of these composite materials is a big problem. According to the current separation technology, it will cost a lot of economic costs, and the processing effect is not satisfactory.

[0003] The new green BOPE / PE single material is a polyethylene (PE)-based material made using a specific process. It is a single-material plastic. PE stands for polyethylene, and BOPE stands for biaxially oriented polyethylene. The biaxial stretching process aligns the PE molecular chains, significantly improving the material's mechanical properties (such as strength, transparency, and barrier properties). Single material refers to the fact that all structural layers of the packaging (such as film, label, and adhesive) use the same chemical substrate (PE in this case), making it easy to recycle without the need for stratification. The core features of BOPE / PE single material are high performance (BOPE's stretching process makes it thinner but stronger than ordinary PE film, and it can replace materials such as PA and PET in traditional composite films), recyclability (because the entire structure is PE, there is no need to separate different materials and it can directly enter the PE recycling stream (such as physical regeneration or chemical recycling), meeting the requirements of the circular economy), and lightweight (high strength allows for reduced material usage and lowers the carbon footprint).

[0004] Currently, in practical applications, BOPE / PE single-material packaging is prone to wrinkling and tearing during hot-press flat-sealing due to BOPE's poor heat resistance. Therefore, the heat-sealing temperature gradient between BOPE and PE needs to be improved. To address this issue, we have proposed a new technical solution. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a low-temperature PE heat-sealing film for use in a single BOPE / PE material and a preparation method thereof. The technical solution adopted is:

[0006] In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

[0007] A low-temperature PE heat-sealing film applied to a single BOPE / PE material, comprising a heat-sealing layer, a core layer and a corona layer;

[0008] The heat seal layer comprises the following raw material components: butene-octene copolymer (POE), metallocene polyethylene (mPE), low-density polyethylene, an anti-blocking agent, a slip agent, and a processing aid;

[0009] The core layer comprises the following raw material components: linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and anti-reflection nucleating agent masterbatch;

[0010] The corona layer comprises the following raw material components: linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and anti-reflection nucleating agent masterbatch.

[0011] As a further embodiment of the present invention, the heat-sealing layer comprises the following raw material components in parts by weight: 30-50 parts of butene-octene copolymer (POE), 30-50 parts of metallocene polyethylene (mPE), 5-35 parts of low-density polyethylene, 1-5 parts of an anti-blocking agent, 1-3 parts of a lubricant, and 1-3 parts of a processing aid.

[0012] As a further embodiment of the present invention, the heat-sealing layer comprises the following raw material components in parts by weight: 50 parts of butene-octene copolymer (POE), 40 parts of metallocene polyethylene (mPE), 5 parts of low-density polyethylene, 3 parts of anti-blocking agent, 1 part of lubricant and 1 part of processing aid.

[0013] As a further embodiment of the present invention, the processing aid is a PPA aid.

[0014] As a further solution of the present invention, the core layer comprises the following raw material components in parts by weight: 40-50 parts of linear low-density polyethylene (LLDPE), 40-60 parts of high-density polyethylene (HDPE) and 1-3 parts of anti-reflection nucleating agent masterbatch.

[0015] As a further solution of the present invention, the core layer comprises the following raw material components in parts by weight: 48 parts of linear low-density polyethylene (LLDPE), 50 parts of high-density polyethylene (HDPE) and 2 parts of anti-reflection nucleating agent masterbatch.

[0016] As a further solution of the present invention, the corona layer comprises the following raw material components in parts by weight: 35-70 parts of linear low-density polyethylene (LLDPE), 30-60 parts of high-density polyethylene (HDPE) and 1-5 parts of anti-reflection nucleating agent masterbatch.

[0017] As a further solution of the present invention, the corona layer comprises the following raw material components in parts by weight: 66 parts of linear low-density polyethylene (LLDPE), 30 parts of high-density polyethylene (HDPE) and 4 parts of anti-reflection nucleating agent masterbatch.

[0018] As a further solution of the present invention, the anti-reflection nucleating agent masterbatch is an anti-reflection nucleating agent PE masterbatch.

[0019] The present invention also provides a method for preparing a low-temperature PE heat-sealing film applied to a single BOPE / PE material, comprising the following steps:

[0020] The raw materials of the heat sealing layer, the core layer and the corona layer are respectively placed into three extruders for melting. The molten materials from the three extruders are co-extruded through a die head to form a multi-layer composite film, and then subjected to inflation cooling, film forming, corona treatment and winding to obtain the low-temperature PE heat sealing film used in BOPE / PE single material.

[0021] Compared with the prior art, the beneficial effects of the present invention are specifically embodied in:

[0022] The low-temperature PE heat-sealing film provided by the present invention for use in a single BOPE / PE material adopts a three-layer structure. The heat-sealing layer is made of an optimized combination of materials such as metallocene polyethylene (mPE), butene-octene copolymer (POE), and low-density polyethylene (LDPE), and polymer processing aids, anti-blocking agents, and slip agents are added to optimize the heat-sealing performance. The corona layer and core layer are made of materials such as high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE), and additives such as anti-reflective nucleating agents are added to optimize the heat resistance and stiffness of the corona layer and core layer. A certain softening point temperature gradient is formed between the corona layer, the core layer, and the heat-sealing layer, and the relationship between heat-sealing performance and tensile properties is balanced. Studies have shown that the low-temperature PE heat-sealing film prepared by the present invention for use in a single BOPE / PE material has a BOPE heat-sealing temperature gradient of above 30°C, and the heat resistance of the three-layer structure of the heat-sealing layer, the core layer, and the corona layer also increases in a gradient, with a heat-sealing strength greater than 10N / 15mm.

[0023] The present invention is further described in detail by referring to the specific embodiments below: DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Example 1

[0026] A low-temperature PE heat-sealing film applied to a single BOPE / PE material, comprising a heat-sealing layer, a core layer and a corona layer;

[0027] The heat seal layer comprises the following raw material components in parts by weight: 30 parts of butene-octene copolymer (POE), 30 parts of metallocene polyethylene (mPE), 35 parts of low-density polyethylene, 3 parts of anti-blocking agent, 1 part of lubricant, and 1 part of processing aid (PPA);

[0028] The core layer comprises the following raw material components in parts by weight: 48 parts of linear low-density polyethylene (LLDPE), 50 parts of high-density polyethylene (HDPE) and 2 parts of a PE masterbatch of a transparent nucleating agent;

[0029] The corona layer comprises the following raw material components in parts by weight: 68 parts of linear low-density polyethylene (LLDPE), 30 parts of high-density polyethylene (HDPE), and 2 parts of a PE masterbatch as a transparent nucleating agent.

[0030] The preparation method of a low-temperature PE heat-sealing film for use in a single BOPE / PE material comprises the following steps: placing raw materials for a heat-sealing layer, a core layer, and a corona layer into three extruders for melting respectively; the molten materials from the three extruders are co-extruded through a die head for film blowing to form a multi-layer composite; and then undergoing inflation cooling, film forming, corona treatment, and winding to obtain the low-temperature PE heat-sealing film for use in a single BOPE / PE material.

[0031] Example 2

[0032] A low-temperature PE heat-sealing film applied to a single BOPE / PE material, comprising a heat-sealing layer, a core layer and a corona layer;

[0033] The heat seal layer comprises the following raw material components in parts by weight: 50 parts of butene-octene copolymer (POE), 40 parts of metallocene polyethylene (mPE), 5 parts of low-density polyethylene, 3 parts of anti-blocking agent, 1 part of slip agent and 1 part of processing aid (PPA);

[0034] The core layer comprises the following raw material components in parts by weight: 48 parts of linear low-density polyethylene (LLDPE), 50 parts of high-density polyethylene (HDPE) and 2 parts of a PE masterbatch of a transparent nucleating agent;

[0035] The corona layer comprises the following raw material components in parts by weight: 66 parts of linear low-density polyethylene (LLDPE), 30 parts of high-density polyethylene (HDPE) and 4 parts of anti-reflection nucleating agent PE masterbatch.

[0036] The preparation method of a low-temperature PE heat-sealing film for use in a single BOPE / PE material comprises the following steps: placing raw materials for a heat-sealing layer, a core layer, and a corona layer into three extruders for melting respectively; the molten materials from the three extruders are co-extruded through a die head for film blowing to form a multi-layer composite; and then undergoing inflation cooling, film forming, corona treatment, and winding to obtain the low-temperature PE heat-sealing film for use in a single BOPE / PE material.

[0037] Example 3

[0038] A low-temperature PE heat-sealing film applied to a single BOPE / PE material, comprising a heat-sealing layer, a core layer and a corona layer;

[0039] The heat seal layer comprises the following raw material components in parts by weight: 40 parts of butene-octene copolymer (POE), 50 parts of metallocene polyethylene (mPE), 5 parts of low-density polyethylene, 3 parts of anti-blocking agent, 1 part of slip agent and 1 part of processing aid (PPA);

[0040] The core layer comprises the following raw material components in parts by weight: 48 parts of linear low-density polyethylene (LLDPE), 50 parts of high-density polyethylene (HDPE) and 2 parts of a PE masterbatch of a transparent nucleating agent;

[0041] The corona layer comprises the following raw material components in parts by weight: 37 parts of linear low-density polyethylene (LLDPE), 60 parts of high-density polyethylene (HDPE); and 3 parts of PE masterbatch, an anti-reflection nucleating agent.

[0042] The preparation method of a low-temperature PE heat-sealing film for use in a single BOPE / PE material comprises the following steps: placing raw materials for a heat-sealing layer, a core layer, and a corona layer into three extruders for melting respectively; the molten materials from the three extruders are co-extruded through a die head for film blowing to form a multi-layer composite; and then undergoing inflation cooling, film forming, corona treatment, and winding to obtain the low-temperature PE heat-sealing film for use in a single BOPE / PE material.

[0043] A 50 μm thick low-temperature heat-sealable PE film was composited with a 40 μm thick BOPE film, and the heat-sealability of the composite material was tested. The test results are shown in Table 1.

[0044] Table 1. BOPE 40 / PE 50 Test results of heat sealing performance of single material composite film

[0045]

[0046] From the experimental results in Table 1, it can be seen that the PE heat-sealing films prepared in Examples 1 to 3 are applied to composite films made of BOPE / PE single materials. The heat-sealing temperature gradient is above 30°C, and the heat-sealing strength is greater than 11N / 15mm, showing excellent performance.

[0047] In particular, the low-temperature heat-sealable PE film prepared in Example 2, which was used to make a BOPE / PE single-material composite film, had a heat-seal temperature gradient and heat-seal strength significantly higher than the composite films prepared in Examples 1 and 3. This demonstrates that the amounts of raw materials used in the heat-seal layer, core layer, and corona layer of the present invention are critical. A low-temperature heat-sealable PE film prepared at the amounts of raw materials used in the heat-seal layer, core layer, and corona layer of Example 2, when applied to a composite film made of a single BOPE / PE material, had a heat-seal temperature gradient and heat-seal strength significantly higher than those of the other examples.

[0048] The above preferred embodiments should be regarded as examples of the implementation methods of the present application scheme. Any technical deductions, replacements, improvements, etc. that are identical or similar to the present application scheme or made based on it should be regarded as within the scope of protection of this patent.

[0049] Although the present invention has been described in detail with reference to the above embodiments, it will be apparent to those skilled in the art from this disclosure that various changes or modifications may be made to the present invention without departing from the principles and spirit of the invention as defined in the claims. Therefore, the detailed description of the disclosed embodiments is intended to be illustrative only and not to limit the present invention, which is to be defined by the claims.

Claims

1. A low-temperature PE heat-sealing film used in BOPE / PE single material, characterized in that: Contains heat seal layer, core layer and corona layer; The heat seal layer comprises the following raw material components: butene-octene copolymer, metallocene polyethylene, low-density polyethylene, an anti-blocking agent, a slip agent and a processing aid; The core layer comprises the following raw material components: linear low-density polyethylene, high-density polyethylene and anti-reflection nucleating agent masterbatch; The corona layer comprises the following raw material components: linear low-density polyethylene, high-density polyethylene and anti-reflection nucleating agent masterbatch.

2. The low-temperature PE heat-sealing film used in BOPE / PE single material according to claim 1, characterized in that: The heat-sealing layer comprises the following raw material components in parts by weight: 30-50 parts of butene-octene copolymer, 30-50 parts of metallocene polyethylene, 5-35 parts of low-density polyethylene, 1-5 parts of an anti-blocking agent, 1-3 parts of a slip agent and 1-3 parts of a processing aid.

3. The low-temperature PE heat-sealing film used in BOPE / PE single material according to claim 2, characterized in that: The heat-sealing layer comprises the following raw material components in parts by weight: 50 parts of butene-octene copolymer, 40 parts of metallocene polyethylene, 5 parts of low-density polyethylene, 3 parts of anti-blocking agent, 1 part of lubricant and 1 part of processing aid.

4. The low-temperature PE heat-sealing film for BOPE / PE single material according to claim 1, characterized in that: The processing aid is a PPA aid.

5. The low-temperature PE heat-sealing film used in BOPE / PE single material according to claim 1, characterized in that: The core layer comprises the following raw material components in parts by weight: 40-50 parts of linear low-density polyethylene, 40-60 parts of high-density polyethylene and 1-3 parts of anti-reflection nucleating agent masterbatch.

6. The low-temperature PE heat-sealing film for use in BOPE / PE single material according to claim 5, characterized in that: The core layer comprises the following raw material components in parts by weight: 48 parts of linear low-density polyethylene, 50 parts of high-density polyethylene and 2 parts of anti-reflection nucleating agent masterbatch.

7. The low-temperature PE heat-sealing film for use in BOPE / PE single material according to claim 1, characterized in that: The corona layer comprises the following raw material components in parts by weight: 35-70 parts of linear low-density polyethylene, 30-60 parts of high-density polyethylene and 1-5 parts of anti-reflection nucleating agent masterbatch.

8. The low-temperature PE heat-sealing film for use in BOPE / PE single material according to claim 7, characterized in that: The corona layer comprises the following raw material components in parts by weight: 66 parts of linear low-density polyethylene, 30 parts of high-density polyethylene and 4 parts of anti-reflection nucleating agent masterbatch.

9. The low-temperature PE heat-sealing film used in BOPE / PE single material according to any one of claims 5 to 8, characterized in that: The anti-reflection nucleating agent masterbatch is an anti-reflection nucleating agent PE masterbatch.

10. The method for preparing a low-temperature PE heat-sealing film for use in a single BOPE / PE material according to any one of claims 1 to 9, characterized in that: The following steps are included: The raw materials of the heat sealing layer, the core layer and the corona layer are respectively placed into three extruders for melting. The molten materials from the three extruders are co-extruded through a die head to form a multi-layer composite film, and then subjected to inflation cooling, film forming, corona treatment and winding to obtain the low-temperature PE heat sealing film used in BOPE / PE single material.

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