A polyvinyl label film and a method of making

Abstract

The application relates to the technical field of label film, and discloses a polyvinyl label film and a preparation method thereof, which comprises the following raw materials: linear low-density polyethylene, high-density polyethylene, low-density polyethylene, polyethylene color master batch, high-surface-energy filler and dicumyl peroxide. The high-surface-energy filler is prepared, is melt-grafted with a polyethylene matrix under the action of dicumyl peroxide, and on one hand, can cause chemical crosslinking between microcrystalline cellulose and the polyethylene matrix, forms good interface combination, and can also cause physical entanglement with the polyethylene matrix, has good compatibility with each raw material, and has good mechanical properties; on the other hand, introduces a polar group and polar microcrystalline cellulose, obviously improves the surface energy of the polyvinyl label film, effectively improves the printing performance of the label film, meets the printing requirements of solvent-based ink or water-based ink, realizes the effect that the label film can be printed without surface treatment such as corona, and simplifies the process flow of the label film.

Description

Technical Field

[0001] This invention relates to the field of label film technology, and in particular to a polyethylene-based label film and its preparation method. Background Technology

[0002] Currently, the main raw materials for label film production are typically polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET), and polyethylene (PE). Among these, polyethylene, with its excellent flexibility, low-temperature resistance, low cost, mature processing technology, heat-sealing adaptability, and safety and non-toxicity, has become one of the most cost-effective application materials in the label film field and is widely used in daily chemical bottle packaging, food packaging, electronics, and pharmaceuticals.

[0003] However, polyethylene is a non-polar material with low surface energy and an inert surface, resulting in poor wettability, adhesion, dyeability, and printability, which limits its further application in label films. To improve the printability of polyethylene, surface treatments such as corona treatment are typically applied to introduce polar groups onto the film surface. However, the effects of corona treatment are not long-lasting, and friction and heating can destroy the corona effect. Based on this, this invention proposes a polyethylene-based label film and its preparation method. The prepared label film exhibits good mechanical and printability properties and can be directly printed on without corona treatment or other surface treatments, simplifying the label film manufacturing process. Summary of the Invention

[0004] This invention proposes a polyethylene-based label film and its preparation method. The prepared label film has good printing and mechanical properties, which solves the problem of poor printing performance of polyethylene, which requires surface treatment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A polyethylene-based label film, comprising the following raw materials in parts by weight: 40-60 parts linear low-density polyethylene; 10-16 parts high-density polyethylene; 30-40 parts low-density polyethylene; 8-14 parts polyethylene masterbatch; 3-5 parts of high surface energy filler; 0.2-0.5 parts dicumyl peroxide; Among them, the high surface energy filler is prepared by surface modification of epoxidized microcrystalline cellulose with a compatible surface modifier.

[0006] Furthermore, the preparation method of the compatibility surface modifier is as follows: One molar equivalent of diethanolamine reacts with one molar equivalent of octadecyl methacrylate in an aminoenyl addition reaction to give an intermediate; One molar equivalent of the intermediate and one molar equivalent of maleic anhydride undergo esterification under the action of p-toluenesulfonic acid to obtain a compatible surface modifier.

[0007] Furthermore, the preparation method of the epoxidized microcrystalline cellulose is as follows: The product is prepared by adding 3-glycidyl etheroxypropyltrimethoxysilane and a pH adjuster to methanol as a solvent, followed by the addition of microcrystalline cellulose, through the chemical bonding between the siloxane of 3-glycidyl etheroxypropyltrimethoxysilane and microcrystalline cellulose.

[0008] Furthermore, the pH adjuster is glacial acetic acid.

[0009] Furthermore, the thickness of the label film is 60-80 μm.

[0010] A method for preparing a polyethylene-based label film is as follows: Step 1: Mix linear low-density polyethylene, high-density polyethylene, low-density polyethylene, polyethylene masterbatch, high surface energy filler, and dicumyl peroxide evenly, melt-blend through a twin-screw extruder, and extrude and granulate to obtain composite masterbatch; Step 2: Add the composite masterbatch into a single-screw extruder, blow film, cool and shape it, trim the edges and roll it up to form a polyethylene label film.

[0011] Furthermore, in step one, the temperature of the twin-screw extruder from the processing section to the die head is 165-175℃, 175-185℃, 185-195℃, 185-195℃, 180-190℃, and 180-190℃.

[0012] Furthermore, in step two, the inflation ratio is 2.3-2.6.

[0013] The beneficial effects of this invention are as follows: This invention prepares a high surface energy filler, which is then melt-grafted onto a polyethylene matrix under the action of dicumyl peroxide. On the one hand, this allows microcrystalline cellulose to chemically crosslink with the polyethylene matrix, forming a good interfacial bond, and also allows for physical entanglement with the polyethylene matrix. It exhibits good compatibility with various raw materials and good mechanical properties. On the other hand, the introduction of polar groups and polar microcrystalline cellulose significantly improves the surface energy of the polyethylene label film. Experimental results show that the surface energy of the polyethylene label film prepared by this invention is greater than or equal to 40 mN / m, effectively improving the printing performance of the label film and meeting the printing requirements of solvent-based inks or water-based inks. It achieves the effect of printing without surface treatments such as corona discharge, simplifying the label film manufacturing process. Detailed Implementation

[0014] Experimental Example 1:

[0015] The preparation method for high surface energy fillers is as follows: One molar equivalent of diethanolamine reacts with one molar equivalent of octadecyl methacrylate in an aminoenyl addition reaction to give an intermediate; One molar equivalent of the intermediate and one molar equivalent of maleic anhydride undergo an esterification reaction in the presence of p-toluenesulfonic acid to obtain a compatible surface modifier. 3-Glycidyl etheroxypropyltrimethoxysilane was used to modify the surface of microcrystalline cellulose to obtain epoxidized microcrystalline cellulose; A compatible surface modifier undergoes a hydroxyl / carboxyl-epoxy ring-opening addition reaction with epoxidized microcrystalline cellulose under the action of triethylamine to obtain a high surface energy filler.

[0016] The specific steps for preparing high surface energy fillers are as follows: Step 1: Add 1g of diethanolamine and 3.4g of octadecyl methacrylate to 20mL of anhydrous ethanol at 50℃, mix well, heat to 75℃, react for 8h, remove anhydrous ethanol under reduced pressure, wash, cool, and dry to obtain the intermediate. Step 2: Add 4.5g of intermediate and 1g of maleic anhydride to 20mL of toluene, mix well, add 0.1g of p-toluenesulfonic acid, heat to 95℃, react for 6h, remove toluene by vacuum distillation to obtain a compatible surface modifier. The chemical structural formula of the compatibility surface modifier is: ; The 1H NMR characterization results of the compatible surface modifier are as follows: 1 H NMR (400MHz, DMSO-D6, δ, ppm): 0.87-0.91 (m, 3H), 1.09-1.12 (m, 3H), 1.26-1.40 (m, 30H), 1.63-1.69 (m, 2H), 2.57-2.66 (m, 5H), 2.84-2.93(m, 2H), 3.49-3.55(m, 2H), 3.91-3.94(t, 1H), 4.05-4.07(t, 2H), 4.16-4.24(m, 2H), 6.24-6.45(m, 2H), 11.69(s, 1H); Step 3: Add 8 mL of 3-glycidyl etheroxypropyltrimethoxysilane to 50 mL of 90% methanol solution, stir and mix well, add glacial acetic acid to adjust the pH to 4, then add 3 g of microcrystalline cellulose, stir and disperse evenly, heat to 70℃, stir for 8 h, filter, wash, and dry to obtain epoxidized microcrystalline cellulose. Step 4: Add 5.4g of the compatibility surface modifier to 50mL of anhydrous toluene, mix well, heat to 60℃, slowly add 2.4g of epoxidized microcrystalline cellulose and 0.1mL of triethylamine, heat to 80℃ after addition, keep the temperature for 4h, filter, wash, and dry to obtain the high surface energy filler.

[0017] Implementation: 1:

[0018] A polyethylene-based label film, comprising the following raw materials in parts by weight: 50 parts linear low-density polyethylene (grade MLPE-8060); 14 parts of high-density polyethylene (brand name DGDA6098); 35 parts low-density polyethylene (grade LD608); 11 parts titanium dioxide masterbatch; Three portions of high surface energy filler (prepared in Experimental Example 1); 0.4 parts dicumyl peroxide.

[0019] A method for preparing a polyethylene-based label film is as follows: Step 1: Linear low-density polyethylene, high-density polyethylene, low-density polyethylene, titanium dioxide masterbatch, high surface energy filler, and dicumyl peroxide are mixed evenly and then melt-blended in a twin-screw extruder and extruded and granulated. The temperature of the twin-screw extruder from the processing section to the die head is 170℃, 180℃, 190℃, 190℃, 185℃, and 185℃, respectively, to obtain composite masterbatch. Step 2: Add the composite masterbatch to a single-screw extruder and blown film. After blowing the film, the blow-up ratio is 2.4. Then, after cooling and shaping, the edges are trimmed and the film is wound up to form a polyethylene label film with a thickness of 65μm.

[0020] Implementation: 2:

[0021] A polyethylene-based label film, comprising the following raw materials in parts by weight: 50 parts linear low-density polyethylene (grade MLPE-8060); 14 parts of high-density polyethylene (brand name DGDA6098); 35 parts low-density polyethylene (grade LD608); 11 parts titanium dioxide masterbatch; Four portions of high surface energy filler (prepared in Experimental Example 1); 0.4 parts dicumyl peroxide.

[0022] A method for preparing a polyethylene-based label film is as follows: Step 1: Linear low-density polyethylene, high-density polyethylene, low-density polyethylene, titanium dioxide masterbatch, high surface energy filler, and dicumyl peroxide are mixed evenly and then melt-blended in a twin-screw extruder and extruded and granulated. The temperature of the twin-screw extruder from the processing section to the die head is 170℃, 180℃, 190℃, 190℃, 185℃, and 185℃, respectively, to obtain composite masterbatch. Step 2: Add the composite masterbatch to a single-screw extruder and blown film. After blowing the film, the blow-up ratio is 2.4. Then, after cooling and shaping, the edges are trimmed and the film is wound up to form a polyethylene label film with a thickness of 65μm.

[0023] Implementation: 3:

[0024] A polyethylene-based label film, comprising the following raw materials in parts by weight: 50 parts linear low-density polyethylene (grade MLPE-8060); 14 parts of high-density polyethylene (brand name DGDA6098); 35 parts low-density polyethylene (grade LD608); 11 parts titanium dioxide masterbatch; Five portions of high surface energy filler (prepared in Experimental Example 1); 0.4 parts dicumyl peroxide.

[0025] A method for preparing a polyethylene-based label film is as follows: Step 1: Linear low-density polyethylene, high-density polyethylene, low-density polyethylene, titanium dioxide masterbatch, high surface energy filler, and dicumyl peroxide are mixed evenly and then melt-blended in a twin-screw extruder and extruded and granulated. The temperature of the twin-screw extruder from the processing section to the die head is 170℃, 180℃, 190℃, 190℃, 185℃, and 185℃, respectively, to obtain composite masterbatch. Step 2: Add the composite masterbatch to a single-screw extruder and blown film. After blowing the film, the blow-up ratio is 2.4. Then, after cooling and shaping, the edges are trimmed and the film is wound up to form a polyethylene label film with a thickness of 65μm.

[0026] Comparative Example 1: A polyethylene-based label film, comprising the following raw materials in parts by weight: 50 parts linear low-density polyethylene (grade MLPE-8060); 14 parts of high-density polyethylene (brand name DGDA6098); 35 parts low-density polyethylene (grade LD608); 11 parts titanium dioxide masterbatch.

[0027] A method for preparing a polyethylene-based label film is as follows: Step 1: Mix linear low-density polyethylene, high-density polyethylene, low-density polyethylene, and titanium dioxide masterbatch evenly, melt-blend them in a twin-screw extruder, and then extrude and granulate them. The temperature of the twin-screw extruder from the processing section to the die head is 170℃, 180℃, 190℃, 190℃, 185℃, and 185℃, respectively, to obtain composite masterbatch. Step 2: Add the composite masterbatch to a single-screw extruder and blown film. After blowing the film, the blow-up ratio is 2.4. Then, after cooling and shaping, the edges are trimmed and the film is wound up to form a polyethylene label film with a thickness of 65μm.

[0028] Performance testing:

[0029] I. Surface Energy Testing The surface energy of the polyethylene label films prepared in Examples 1-3 and Comparative Example 1 was tested using a dyne pen. After being stored at room temperature for 60 days, the surface energy of the label films was tested again. The higher the surface energy, the higher the polarity of the film surface. The test results are shown in Table 1. Table 1. Test results of surface energy of polyethylene label film

[0030] Practice has shown that: When the surface energy of polyethylene film is 38-42 mN / m, solvent-based inks or water-based inks can be used for printing. When the surface energy of the polyethylene film is 42-46 mN / m, UV inks can be used for printing. When the surface energy of the polyethylene film is 42-48 mN / m, water-soluble ink can be used for printing. As shown in Table 1, the surface energy of the polyethylene label film prepared in the embodiments of the present invention is significantly improved, with the surface energy reaching greater than or equal to 40mN / m, which allows for printing with solvent-based inks or water-based inks without surface treatments such as corona discharge.

[0031] II. Mechanical Property Testing According to GB / T 1040.3-2006 standard, the tensile properties and elongation at break of the polyethylene-based label films prepared in Examples 1-3 were tested, and the test results are shown in Table 2: Table 2. Test results of mechanical properties of polyethylene label film

Claims

1. A polyethylene-based label film, characterized in that, Including the following parts by weight of raw materials: 40-60 parts linear low-density polyethylene; 10-16 parts high-density polyethylene; 30-40 parts low-density polyethylene; 8-14 parts polyethylene masterbatch; 3-5 parts of high surface energy filler; 0.2-0.5 parts dicumyl peroxide; Among them, the high surface energy filler is prepared by surface modification of epoxidized microcrystalline cellulose with a compatible surface modifier; The chemical structural formula of the compatibility surface modifier is: ； The preparation method of the epoxidized microcrystalline cellulose is as follows: The product is prepared by adding 3-glycidyl etheroxypropyltrimethoxysilane and a pH adjuster to a 90-95% methanol solution as a solvent, followed by microcrystalline cellulose. The chemical bonding between the siloxane of 3-glycidyl etheroxypropyltrimethoxysilane and the microcrystalline cellulose is achieved through the chemical bonding between the siloxane of 3-glycidyl etheroxypropyltrimethoxysilane and the microcrystalline cellulose.

2. The polyethylene-based label film according to claim 1, characterized in that, The preparation method of the compatibility surface modifier is as follows: One molar equivalent of diethanolamine reacts with one molar equivalent of octadecyl methacrylate in an aminoenyl addition reaction to give an intermediate; One molar equivalent of the intermediate and one molar equivalent of maleic anhydride undergo esterification under the action of p-toluenesulfonic acid to obtain a compatible surface modifier.

3. The polyethylene-based label film according to claim 1, characterized in that, The pH adjuster is glacial acetic acid.

4. A polyethylene-based label film according to claim 1, characterized in that, The thickness of the label film is 60-80 μm.

5. A method for preparing a polyethylene-based label film according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Mix linear low-density polyethylene, high-density polyethylene, low-density polyethylene, polyethylene masterbatch, high surface energy filler, and dicumyl peroxide evenly, melt-blend through a twin-screw extruder, and extrude and granulate to obtain composite masterbatch; Step 2: Add the composite masterbatch into a single-screw extruder, blow film, cool and shape it, trim the edges and roll it up to form a polyethylene label film.

6. The method for preparing a polyethylene-based label film according to claim 5, characterized in that, In step one, the temperature of the twin-screw extruder from the processing section to the die head is 165-175℃, 175-185℃, 185-195℃, 185-195℃, 180-190℃, and 180-190℃.

7. The method for preparing a polyethylene-based label film according to claim 5, characterized in that, In step two, the blow-out ratio of the blown film blown by the blown film machine is 2.3-2.6.

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