High-temperature-resistant high-toughness high-transparency PE (polyethylene) heat-shrinkable film and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant high-toughness high-transparency PE heat-shrinkable film and a preparation method thereof, and relates to the field of PE heat-shrinkable films, and aims to solve the problems of poor high-temperature resistance, poor film toughness and poor transparency in the prior art, the adopted technical scheme is as follows: the high-temperature-resistant high-toughness high-transparency PE heat-shrinkable film comprises a layer A, a layer B and a layer C, the three layers are connected in sequence, the layer A comprises LDPE, HDPE, MLLDPE, PMP, OBC and PPA, and the layer B comprises LDPE, HDPE, MLLDPE, PMP, OBC and PPA; the layer B comprises LDPE (Low-Density Polyethylene), LLDPE (Linear Low-Density Polyethylene), HDPE (High- And the layer C comprises LDPE, MLLDPE, HDPE, POE, a slipping agent, a toughening agent and a coupling agent. The temperature resistance range, the toughness and the transparency of the PE heat shrink film are greatly improved, the problem that the PE heat shrink film is unstable in the using process is solved, the production efficiency of a user is greatly improved, the cost is saved, and the PE heat shrink film can be used for bundling packaging of beer, beverages, dairy products and the like.

Description

Technical Field

[0001] This invention relates to the field of PE heat shrink film technology, specifically to a high-temperature resistant, high-toughness, and high-transparency PE heat shrink film and its preparation method. Background Technology

[0002] PE shrink film is widely used in the packaging industry due to its low cost, ease of processing, and environmental friendliness. However, with industrial development, the performance requirements for PE heat shrink film are becoming increasingly stringent. Traditional PE heat shrink film suffers from the following problems in terms of high temperature resistance, high toughness, and high transparency, making it difficult to simultaneously meet these requirements:

[0003] Poor high temperature resistance: When used in some high-temperature environments, ordinary heat shrink film is prone to softening, deformation, cracking, sticking, and holes, making it difficult to meet the requirements of high-temperature production and use.

[0004] Poor film toughness: The film is prone to breakage when it shrinks rapidly or is subjected to external impact, and cannot effectively protect the packaged items, which limits the application of the film in some complex packaging scenarios;

[0005] Poor transparency: During the processing of the film, the high crystallinity of the raw resin and the uneven dispersion of additives lead to a decrease in light transmittance. At the same time, when the film is used, after entering the shrink oven, water mist and rapid shrinkage and cooling cause fogging after packaging, which affects the display effect of the product. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the existing defects and provide a high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film and its preparation method, which can effectively solve the problems in the background art.

[0007] To achieve the above objectives, this invention first discloses a high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film. The technical solution adopted includes a layer A, a layer B, and a layer C, which are connected sequentially. Each layer comprises the following components by weight:

[0008] Layer A resin composition: 30-35 parts low-density polyethylene (LDPE), 25-30 parts high-density polyethylene (HDPE), 30-40 parts metallocene (MLLDPE), 3-5 parts nano-grade high-temperature resistant PMP (poly-4-methyl-1-pentene) resin, 2-5 parts olefin block copolymer resin (OBC); 0.5-1 part PPA lubricating rheology masterbatch; in the high-temperature resistant layer, the PMP resin particle size is 50-100 nm;

[0009] B-layer resin components: 30-40 parts low-density polyethylene (LDPE), 15-20 parts linear low-density polyethylene (LLDPE), 25-30 parts high-density polyethylene (HDPE), 10-25 parts metallocene (MLLDPE), and 0.5-1 part anti-reflective agent. The anti-reflective agent is p-methyldibenzylsorbitol, a sorbitol derivative, which can accelerate the crystallization rate of polyethylene resin and increase crystallinity to improve the transparency of the film.

[0010] C-layer resin components: 25-30 parts low-density polyethylene (LDPE), 25-30 parts metallocene (MLLDPE), 25-30 parts high-density polyethylene (HDPE), 10-20 parts polyolefin elastomer (POE), 1-1.5 parts slip agent, 3-5 parts nanoparticle toughening agent (calcium carbonate), and 1-3 parts modified nanoscale silicon oxide coupling agent.

[0011] This invention also discloses a method for preparing the above-mentioned high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film, the technical solution of which includes the following steps:

[0012] Step 1: The A layer component is first made by fully mixing and modifying the olefin block copolymer resin, high temperature resistant PMP resin, PPA lubricating rheology masterbatch and LDPE resin in a high-speed mixer, and then fully mixing it with HDPE resin and MLLDPE resin to make high temperature resistant outer layer blended granules.

[0013] Step 2: The B-layer component, LDPE resin and methyl dibenzyl sorbitol anti-reflective agent, are mixed in a high-speed mixer, and then mixed with LLDPE resin, HDPE resin and MLLDPE resin according to the component ratio to form intermediate layer blended granules.

[0014] Step 3: The C layer component is prepared by fully blending and modifying LDPE resin, polyolefin elastomer resin, nano-sized silicon oxide coupling agent, and nanoparticle toughening agent, and then fully mixing it with MLLDPE resin and slip agent to form toughened inner layer blend granules.

[0015] Step 4: Produced on a three-layer co-extrusion blown film machine, the blended granules prepared in steps 1, 2, and 3 are co-extruded and melted layer by layer.

[0016] As a preferred embodiment of the present invention, the preparation method includes the following steps:

[0017] Step 1: The A layer component is prepared by first fully mixing and modifying 2 parts of olefin block copolymer resin, 3 parts of high temperature resistant PMP resin, 0.5 parts of PPA lubricating rheology masterbatch, and 35 parts of LDPE resin in a high-speed mixer, and then fully mixing it with 30 parts of HDPE resin and 30 parts of MLLDPE resin to prepare high temperature resistant outer layer blended granules.

[0018] Step 2: The B layer component, 30 parts of LDPE resin and 1 part of methyl dibenzyl sorbitol anti-reflective agent are mixed in a high-speed mixer, and then mixed with 20 parts of LLDPE resin, 25 parts of HDPE resin and 25 parts of MLLDPE resin according to the component ratio to make intermediate layer blended granules.

[0019] Step 3: The C layer component is prepared by fully blending and modifying 25 parts LDPE resin, 15 parts polyolefin elastomer resin, 2 parts nano-sized silicon oxide coupling agent, and 5 parts nanoparticle toughening agent, and then fully mixing it with 25 parts MLLDPE resin and 1.5 parts slip agent to form a toughened inner layer blend granule.

[0020] Step 4: Produced on a three-layer co-extrusion blown film machine, the blended granules prepared in steps 1, 2, and 3 are co-extruded and melted layer by layer.

[0021] As a preferred technical solution of the present invention, in step 4, the blended granules obtained in steps 1, 2 and 3 are co-extruded and melted by a twin-screw extruder at an interlayer ratio of 1:2:1, with a screw temperature of 180-230℃, a die temperature of 200-230℃, a machine speed of 35m / min, a blow-up ratio of 2.5-2.8, and a workshop temperature controlled at 25-28℃, to produce a high-temperature resistant, high-toughness, and high-permeability PE heat-shrinkable film.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses OBC resin, high-temperature resistant PMP resin and polyethylene resin to make layer A, which serves as the high-temperature resistant outer layer in the three-layer co-extrusion. The OBC resin increases the temperature control range of the shrink film and has a good toughening effect. The addition of high-temperature resistant PMP resin improves the heat resistance stability, so that the heat resistance can reach about 260°C. This not only improves the heat resistance of the heat shrink film, but also does not affect the shrinkage effect.

[0023] Layer B uses DBS additive, which, when blended with polyethylene resin, can accelerate the crystallization rate of the resin and increase its crystallinity, thereby improving the transparency of the film.

[0024] The use of POE elastomer in the C layer not only improves the toughness and heat shrinkage performance of the film, but also enhances the anti-fouling performance of the film surface after thorough blending and modification with nano-grade calcium carbonate toughening agent and metallocene. This prevents fogging caused by moisture in the shrink oven during use, which would affect the transparency of the packaged product.

[0025] This invention significantly improves the temperature resistance range, toughness, and transparency of PE heat shrink film, solves the problem of unstable performance of PE heat shrink film during use, greatly improves users' production efficiency, and saves costs. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention.

[0027] In the diagram: 1. Layer A; 2. Layer B; 3. Layer C. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] like Figure 1 As shown, this embodiment discloses the first implementation of the present invention, which first discloses a high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film. The technical solution adopted is to include a layer A, a layer B, and a layer C, which are connected in sequence. Each layer includes the following components by weight:

[0031] Layer A components: 2 parts olefin block copolymer (OBC) resin, 3 parts high-temperature resistant PMP (poly-4-methyl-1-pentene) resin (50nm particle size), 0.5 parts PPA lubricating rheology masterbatch, 35 parts LDPE (grade: 2520D) resin, 30 parts HDPE (grade: 7000F) resin and 30 parts MLLDPE (grade: 2703) resin;

[0032] Layer B components: 30 parts LDPE (brand name: 2505D) resin, 1 part methyl dibenzyl sorbitol (DBS) antireflective agent, 20 parts LLDPE (brand name: 7042) resin, 25 parts HDPE (brand name: 5121B) resin and 25 parts MLLDPE (brand name: 3505) resin;

[0033] C-layer components: 25 parts LDPE (grade: 2505D) resin, 15 parts polyolefin elastomer (POE) resin, 2 parts nano-sized silica coupling agent, 5 parts nanoparticle toughening agent (calcium carbonate), 25 parts MLLDPE (grade: 2703) resin and 1.5 parts slip agent.

[0034] This embodiment also discloses a method for preparing the above-mentioned high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film, which includes the following steps:

[0035] Step 1, prepare the A layer component.

[0036] First, olefin block copolymer (OBC) resin, high-temperature resistant PMP (poly-4-methyl-1-pentene) resin, PPA lubricating rheology masterbatch, and LDPE (grade: 2520D) resin are fully blended, modified, and granulated in a high-speed mixer. Then, they are fully mixed with HDPE (grade: 7000F) resin and MLLDPE (grade: 2703) resin to prepare high-temperature resistant outer layer blended granules.

[0037] Step 2, prepare layer B component.

[0038] LDPE (brand name: 2505D) resin and methyl dibenzyl sorbitol (DBS) brightening agent are mixed in a high-speed mixer, and then mixed thoroughly with LLDPE (brand name: 7042) resin, HDPE (brand name: 5121B) resin and MLLDPE (brand name: 3505) resin according to the component ratio to make intermediate layer blended granules.

[0039] Step 3: Prepare the C-layer component.

[0040] LDPE (brand name: 2505D) resin, polyolefin elastomer (POE) resin, nano-sized silica coupling agent, and nanoparticle toughening agent (calcium carbonate) are fully blended and modified, and then fully stirred and mixed with MLLDPE (brand name: 2703) resin and slip agent to prepare toughened inner layer blend granules.

[0041] Step 4: Melt co-extrusion

[0042] Produced on a three-layer co-extrusion blown film machine, the blended granules prepared in steps 1, 2, and 3 are co-extruded and melted by twin screws at an interlayer ratio of 1:2:1. The screw temperature is 230°C, the die temperature is 230°C, the machine speed is 35m / min, the blow-up ratio is 2.8, and the workshop temperature is controlled at 25°C (to facilitate film bubble cooling), resulting in a high-temperature resistant, high-toughness, and high-permeability PE heat-shrinkable film.

[0043] Example 2

[0044] The difference between this embodiment and Embodiment 1 is that each layer of the high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film comprises the following components by weight:

[0045] Layer A components: 5 parts olefin block copolymer (OBC) resin, 5 parts high-temperature resistant PMP (poly-4-methyl-1-pentene) resin (100nm particle size), 1 part PPA lubricating rheology masterbatch, 30 parts LDPE (grade: 2520D) resin, 25 parts HDPE (grade: 7000F) resin and 40 parts MLLDPE (grade: 2703) resin;

[0046] Layer B components: 40 parts LDPE (brand name: 2505D) resin, 0.5 parts methyl dibenzyl sorbitol (DBS) antireflective agent, 15 parts LLDPE (brand name: 7042) resin, 30 parts HDPE (brand name: 5121B) resin and 10 parts MLLDPE (brand name: 3505) resin;

[0047] C-layer components: 30 parts LDPE (grade: 2505D) resin, 20 parts polyolefin elastomer (POE) resin, 3 parts nano-sized silica coupling agent, 3 parts nanoparticle toughening agent (calcium carbonate), 30 parts MLLDPE (grade: 2703) resin and 1 part slip agent.

[0048] In the preparation method of high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film, the difference between this embodiment and Example 1 is that...

[0049] Step 4: Melt co-extrusion

[0050] Produced on a three-layer co-extrusion blown film machine, the blended granules prepared in steps 1, 2, and 3 are co-extruded and melted by twin screws at an interlayer ratio of 1:2:1. The screw temperature is 180°C, the die temperature is 200°C, the machine speed is 35m / min, the blow-up ratio is 2.5, and the workshop temperature is controlled at 28°C to obtain a high-temperature resistant, high-toughness, and high-permeability PE heat-shrinkable film.

[0051] Example 3

[0052] The difference between this embodiment and Embodiment 1 is that each layer of the high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film comprises the following components by weight:

[0053] Layer A components: 3.5 parts olefin block copolymer (OBC) resin, 4 parts high-temperature resistant PMP (poly-4-methyl-1-pentene) resin (75nm particle size), 0.75 parts PPA lubricating rheology masterbatch, 32 parts LDPE (grade: 2520D) resin, 27 parts HDPE (grade: 7000F) resin and 35 parts MLLDPE (grade: 2703) resin;

[0054] Layer B components: 35 parts LDPE (brand name: 2505D) resin, 0.75 parts methyl dibenzyl sorbitol (DBS) antireflective agent, 17 parts LLDPE (brand name: 7042) resin, 27 parts HDPE (brand name: 5121B) resin and 20 parts MLLDPE (brand name: 3505) resin;

[0055] C-layer components: 27 parts LDPE (grade: 2505D) resin, 10 parts polyolefin elastomer (POE) resin, 1 part nano-sized silica coupling agent, 4 parts nanoparticle toughening agent (calcium carbonate), 27 parts MLLDPE (grade: 2703) resin and 1.25 parts slip agent.

[0056] In the preparation method of high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film, the difference between this embodiment and Example 1 is that...

[0057] Step 4: Melt co-extrusion

[0058] Produced on a three-layer co-extrusion blown film machine, the blended granules prepared in steps 1, 2, and 3 are co-extruded and melted by twin screws at an interlayer ratio of 1:2:1. The screw temperature is 200°C, the die temperature is 215°C, the machine speed is 35m / min, the blow-up ratio is 2.7, and the workshop temperature is controlled at 26°C to obtain a high-temperature resistant, high-toughness, and high-permeability PE heat-shrinkable film.

[0059] Comparative Example 1

[0060] There is a PE shrink film with a thickness of 60μm.

[0061] The mechanical properties and temperature resistance of the 60μm heat-shrinkable film prepared in Example 1 were compared with those of Comparative Example 1. The results are as follows:

[0062] Mechanical performance comparison data

[0063]

[0064] Temperature resistance performance comparison data

[0065]

[0066] The above comparison shows that Example 1 has higher mechanical performance than the prior art. When used on a packaging machine, Example 1 can withstand a shrinkage temperature of 265°C without any abnormalities such as holes, cracks, or fogging. The prior art has abnormalities such as holes and fogging when used at 245°C and cannot be used.

[0067] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film, characterized in that, It includes layers A, B, and C, which are connected sequentially. Each layer contains the following components by weight: A-layer resin components: 30-35 parts low-density polyethylene, 25-30 parts high-density polyethylene, 30-40 parts metallocene, 3-5 parts nano-grade high-temperature resistant PMP resin, 2-5 parts olefin block copolymer resin; 0.5-1 parts PPA lubricating rheology masterbatch. B-layer resin components: 30-40 parts of low-density polyethylene, 15-20 parts of linear low-density polyethylene, 25-30 parts of high-density polyethylene, 10-25 parts of metallocene, 0.5-1 part of anti-reflective agent, the anti-reflective agent being p-methyldibenzylsorbitol, a sorbitol derivative. C-layer resin components: 25-30 parts low-density polyethylene, 25-30 parts metallocene, 25-30 parts high-density polyethylene, 10-20 parts polyolefin elastomer, 1-1.5 parts slip agent, 3-5 parts nanoparticle toughening agent, and 1-3 parts modified nanoscale silicon oxide coupling agent.

2. The high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film according to claim 1, characterized in that: The PMP resin has a particle size of 50-100 nm; the nanoparticle toughening agent is calcium carbonate.

3. A method for preparing the high-temperature resistant, high-toughness, and high-transparency PE heat-shrinkable film as described in claim 1, characterized in that, Includes the following steps: Step 1: The A layer component is first made by fully mixing and modifying the olefin block copolymer resin, high temperature resistant PMP resin, PPA lubricating rheology masterbatch and LDPE resin in a high-speed mixer, and then fully mixing it with HDPE resin and MLLDPE resin to make high temperature resistant outer layer blended granules. Step 2: The B-layer component, LDPE resin and methyl dibenzyl sorbitol anti-reflective agent, are mixed in a high-speed mixer, and then mixed with LLDPE resin, HDPE resin and MLLDPE resin according to the component ratio to form intermediate layer blended granules. Step 3: The C layer component is prepared by fully blending and modifying LDPE resin, polyolefin elastomer resin, nano-sized silicon oxide coupling agent, and nanoparticle toughening agent, and then fully mixing it with MLLDPE resin and slip agent to form toughened inner layer blend granules. Step 4: Produced on a three-layer co-extrusion blown film machine, the blended granules prepared in steps 1, 2, and 3 are co-extruded and melted layer by layer.

4. The method according to claim 3, characterized in that, Includes the following steps: Step 1: The A layer component is prepared by first fully mixing and modifying 2 parts of olefin block copolymer resin, 3 parts of high temperature resistant PMP resin, 0.5 parts of PPA lubricating rheology masterbatch, and 35 parts of LDPE resin in a high-speed mixer, and then fully mixing it with 30 parts of HDPE resin and 30 parts of MLLDPE resin to prepare high temperature resistant outer layer blended granules. Step 2: The B layer component, 30 parts of LDPE resin and 1 part of methyl dibenzyl sorbitol anti-reflective agent are mixed in a high-speed mixer, and then mixed with 20 parts of LLDPE resin, 25 parts of HDPE resin and 25 parts of MLLDPE resin according to the component ratio to make intermediate layer blended granules. Step 3: The C layer component is prepared by fully blending and modifying 25 parts LDPE resin, 15 parts polyolefin elastomer resin, 2 parts nano-sized silicon oxide coupling agent, and 5 parts nanoparticle toughening agent, and then fully mixing it with 25 parts MLLDPE resin and 1.5 parts slip agent to form a toughened inner layer blend granule. Step 4: Produced on a three-layer co-extrusion blown film machine, the blended granules prepared in steps 1, 2, and 3 are co-extruded and melted layer by layer.

5. The method according to claim 3 or 4, characterized in that: In step 4, the blended granules obtained in steps 1, 2, and 3 are co-extruded and melted using a twin-screw extruder at an interlayer ratio of 1:2:

1. The screw temperature is 180-230°C, the die temperature is 200-230°C, the machine speed is 35m / min, the blow-up ratio is 2.5-2.8, and the workshop temperature is controlled at 25-28°C to produce a high-temperature resistant, high-toughness, and high-permeability PE heat-shrinkable film.

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