A highly transparent PE plastic film and its preparation method

Abstract

The present invention relates to the technical field of plastic films, and provides a highly transparent PE plastic film and a preparation method thereof. The highly transparent PE plastic film comprises the following components in parts by mass: 10-20 parts of LDPE, 40-50 parts of LLDPE, 15-25 parts of HDPE, 20-30 parts of mPE, 15-25 parts of PP, and 2-5 parts of a compatibilizer; the compatibilizer comprises EVA and HDPE-g-MAH. Through the above technical solution, the problem in the prior art that the poor compatibility between PE and PP leads to poor mechanical properties of the PE plastic film is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic films, and specifically, to a highly transparent PE plastic film and a preparation method thereof. Background Art

[0002] At present, the commonly used plastic films in production mainly include two categories: PVC (polyvinyl chloride) and PE (polyethylene). PE plastic films are widely used as packaging materials because of their odorless, non-toxic, good deformation performance, and light weight, and are applied in industries, agriculture, daily use, etc. PE plastic films are formed by blow molding, calendering, casting and other methods from PE raw materials, and have the characteristics of not being easy to absorb dust, easy to clean, and not easy to stick after folding and storing.

[0003] In recent years, the highly transparent PE plastic films on the market are mainly processed from various blends of PE and PP (polypropylene). Various PEs, such as LDPE (high-pressure low-density polyethylene), HDPE (low-pressure high-density polyethylene), LLDPE (linear low-density polyethylene), and mPE (metallocene polyethylene), have good compatibility and can be blended and modified, but the compatibility between PE and PP is poor, which will have an adverse impact on the mechanical properties of PE plastic films. At present, mainly by adding EVA (ethylene-vinyl acetate copolymer) or HDPE-g-MAH (maleic anhydride grafted high-density polyethylene) to improve the compatibility between PE and PP, and then improve the mechanical properties of PE plastic films, but the effect is not ideal. Summary of the Invention

[0004] The present invention provides a highly transparent PE plastic film and a preparation method thereof, which solve the problem that the poor compatibility between PE and PP in the related art leads to poor mechanical properties of PE plastic films.

[0005] The technical solution of the present invention is as follows:

[0006] A highly transparent PE plastic film, comprising the following components in parts by mass: 10-20 parts of LDPE, 40-50 parts of LLDPE, 15-25 parts of HDPE, 20-30 parts of mPE, 15-25 parts of PP, and 2-5 parts of compatibilizer;

[0007] The compatibilizer includes EVA and HDPE-g-MAH.

[0008] The present invention uses LDPE, LLDPE, HDPE, mPE and PP as the matrix materials of the highly transparent PE plastic film, providing excellent comprehensive performance for the plastic film.

[0009] LDPE has good softness, providing high elongation for the plastic film. At the same time, it also has good transparency, heat-sealing performance and chemical resistance, and has low water absorption and excellent water resistance and moisture-proof performance.

[0010] The flexibility, toughness, cold resistance and puncture resistance of LLDPE are all superior to those of LDPE, providing good physical and mechanical properties for plastic films.

[0011] HDPE provides the plastic film with the advantage of a wide service temperature range. It can be used for frozen food packaging, withstand boiling sterilization treatment, and also has high mechanical strength. Using HDPE can reduce the thickness of the plastic film, reduce unit consumption and production costs. At the same time, it also has excellent moisture resistance, oil resistance and chemical resistance, as well as high elongation, tear strength and impact strength.

[0012] mPE enables the plastic film to have high strength and good toughness while also having excellent gloss and low haze, giving it good transparency and making the appearance of the plastic film better.

[0013] PP provides the plastic film with excellent flexural resistance and resilience, as well as good chemical stability, mechanical properties and heat resistance.

[0014] As a further technical solution, the mass ratio of the EVA and HDPE-g-MAH is 1:3 to 3:1.

[0015] As a further technical solution, the mass ratio of the EVA and HDPE-g-MAH is 1:1.

[0016] As a further technical solution, it further includes 4-(3-aminopropyl)aniline.

[0017] As a further technical solution, the mass ratio of the compatibilizer and 4-(3-aminopropyl)aniline is 4:1 to 3.

[0018] As a further technical solution, the mass ratio of the compatibilizer and 4-(3-aminopropyl)aniline is 2:1.

[0019] As a further technical solution, the LDPE includes one or both of LDPE 2427H and LDPE 2420D;

[0020] The LLDPE includes one or both of LLDPE FD 21HN and LLDPE 6218BE;

[0021] The HDPE includes one or both of HDPE ME5000 and HDPE 7000F;

[0022] The mPE includes one or both of mPE 1018FA and mPE 3518PA.

[0023] As a further technical solution, the PP includes one or both of PP DJ-560S and PP J-550S.

[0024] As a further technical solution, the transverse tensile strength is above 49.1 MPa and the longitudinal tensile strength is above 49.9 MPa.

[0025] The present invention also provides a method for preparing a highly transparent PE plastic film, comprising the following steps: after mixing each component evenly, processing and forming to obtain the highly transparent PE plastic film.

[0026] The working principle and beneficial effects of the present invention are as follows:

[0027] 1. The present invention uses EVA and HDPE-g-MAH as compatibilizers, which have a synergistic effect, improve the compatibility between PE and PP, and significantly improve the mechanical properties of the PE plastic film.

[0028] 2. The present invention limits the mass ratio of EVA to HDPE-g-MAH to 1:1, further improving the mechanical properties of the PE plastic film.

[0029] 3. The present invention further adds 4-(3-aminopropyl)aniline. Through the amino group in the molecular structure of 4-(3-aminopropyl)aniline, on the one hand, it acts with HDPE-g-MAH, and on the other hand, it acts with the ester group in the molecular structure of EVA, thereby further improving the compatibility between the components of the PE plastic film and further improving the mechanical properties of the PE plastic film. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0031] Figure 1 It is a transmittance test chart of the PE plastic film obtained in Example 6 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of the present invention.

[0033] In the following examples and comparative examples, EVA is EVA 250 and HDPE-g-MAH is HDPE-g-MAH E265.

[0034] Example 1

[0035] After uniformly mixing 15 parts of LDPE 2427H, 45 parts of LLDPE 6218BE, 20 parts of HDPE ME5000, 25 parts of mPE 1018FA, 20 parts of PP J-550S, 1 part of EVA, and 3 parts of HDPE-g-MAH in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0036] Example 2

[0037] After uniformly mixing 10 parts of LDPE 2420D, 40 parts of LLDPE 6218BE, 15 parts of HDPE ME5000, 20 parts of mPE 3518PA, 15 parts of PP DJ-560S, 0.5 part of EVA, and 1.5 parts of HDPE-g-MAH in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0038] Example 3

[0039] After uniformly mixing 20 parts of LDPE 2427H, 50 parts of LLDPE FD 21HN, 25 parts of HDPE 7000F, 30 parts of mPE 3518PA, 25 parts of PP J-550S, 1.25 parts of EVA, and 3.75 parts of HDPE-g-MAH in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0040] Example 4

[0041] After uniformly mixing 15 parts of LDPE 2427H, 45 parts of LLDPE 6218BE, 20 parts of HDPE ME5000, 25 parts of mPE 1018FA, 20 parts of PP J-550S, 2 parts of EVA, and 2 parts of HDPE-g-MAH in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0042] Example 5

[0043] After uniformly mixing 15 parts of LDPE 2427H, 45 parts of LLDPE 6218BE, 20 parts of HDPE ME5000, 25 parts of mPE 1018FA, 20 parts of PP J-550S, 3 parts of EVA, and 1 part of HDPE-g-MAH in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0044] Example 6

[0045] After mixing 15 parts of LDPE 2427H, 45 parts of LLDPE 6218BE, 20 parts of HDPE ME5000, 25 parts of mPE 1018FA, 20 parts of PP J-550S, 2 parts of EVA, 2 parts of HDPE-g-MAH, and 1 part of 4-(3-aminopropyl)aniline evenly in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0046] Example 7

[0047] After mixing 15 parts of LDPE 2427H, 45 parts of LLDPE 6218BE, 20 parts of HDPE ME5000, 25 parts of mPE 1018FA, 20 parts of PP J-550S, 2 parts of EVA, 2 parts of HDPE-g-MAH, and 2 parts of 4-(3-aminopropyl)aniline evenly in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0048] Example 8

[0049] After mixing 15 parts of LDPE 2427H, 45 parts of LLDPE 6218BE, 20 parts of HDPE ME5000, 25 parts of mPE 1018FA, 20 parts of PP J-550S, 2 parts of EVA, 2 parts of HDPE-g-MAH, and 3 parts of 4-(3-aminopropyl)aniline evenly in a mixer, transfer them to a co-extrusion blown film machine and blow mold at 160 °C to obtain a PE plastic film.

[0050] Comparative Example 1

[0051] The difference from Example 1 is only that EVA is replaced with an equal amount of HDPE-g-MAH.

[0052] Comparative Example 2

[0053] The difference from Example 1 is only that HDPE-g-MAH is replaced with an equal amount of EVA.

[0054] Comparative Example 3

[0055] The difference from Example 1 is only that EVA and HDPE-g-MAH are not added.

[0056] Comparative Example 4

[0057] The difference from Example 1 is only that EVA and HDPE-g-MAH are replaced with an equal amount of 4-(3-aminopropyl)aniline.

[0058] Performance Test:

[0059] (1)Refer to the method in GB / T 1040.3-2006 Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets, with a test speed of 50 mm / min, to conduct the test for tensile strength;

[0060] (2)Refer to Method A in GB / T 9639.1-2008 Plastics films and sheets - Method for determining impact resistance - Free - falling dart method - Part 1: Staircase method to conduct the test for impact strength;

[0061] (3)Refer to the method in QB / T 2358-1998 Test method for heat - seal strength of plastic film packaging bags to conduct the test for heat - seal strength;

[0062] (4)Use the UV - Vis - NIR spectrophotometer Cary 5000 to conduct the test for light transmittance;

[0063] The test results are recorded in Tables 1 - 2.

[0064] Table 1 Tensile strength of PE plastic films obtained in Examples 1 - 8 and Comparative Examples 1 - 4

[0065]

[0066] It can be seen from Table 1 that the transverse tensile strength of the PE plastic film provided by the present invention is above 49.1 MPa, and the longitudinal tensile strength is above 49.9 MPa, having good mechanical properties.

[0067] When comparing Example 1 with Comparative Examples 1 - 3, in Example 1, EVA and HDPE - g - MAH are added, in Comparative Example 1, only HDPE - g - MAH is added, in Comparative Example 2, only EVA is added, and in Comparative Example 3, neither EVA nor HDPE - g - MAH is added. The mechanical properties of the PE plastic film obtained in Example 1 are better than those in Comparative Examples 1 - 3, indicating that EVA and HDPE - g - MAH as compatibilizers have a better effect on improving the compatibility between PE and PP than EVA or HDPE - g - MAH as compatibilizers, and EVA and HDPE - g - MAH have a synergistic effect, which can significantly improve the mechanical properties of the PE plastic film.

[0068] Compared with Comparative Examples 3 to 4, in Example 4, only EVA and HDPE-g-MAH were added; in Examples 6 to 8, EVA, HDPE-g-MAH and 4-(3-aminopropyl)aniline were added; in Comparative Example 3, neither EVA, HDPE-g-MAH nor 4-(3-aminopropyl)aniline was added; in Comparative Example 4, only 4-(3-aminopropyl)aniline was added. The transverse tensile strength and longitudinal tensile strength of the PE plastic film obtained in Comparative Example 4 were lower than those in Comparative Example 1, indicating that adding only 4-(3-aminopropyl)aniline could not only fail to improve the compatibility between PE and PP, but also reduce the mechanical properties of the PE plastic film. The tensile strength of the PE plastic film obtained in Examples 6 to 8 was higher than that in Example 4 and Comparative Examples 3 to 4, indicating that on the basis of adding EVA and HDPE-g-MAH, further adding 4-(3-aminopropyl)aniline could further improve the compatibility between the components of the PE plastic film, and there was a synergistic effect among EVA, HDPE-g-MAH and 4-(3-aminopropyl)aniline, which could significantly improve the mechanical properties of the PE plastic film.

[0069] Table 2 Impact strength, heat seal strength and light transmittance of the PE plastic films obtained in Example 1 and Example 6

[0070]

[0071] As can be seen from Table 2, the PE plastic films provided in Example 1 and Example 6 of the present invention have high impact strength, heat seal strength and transparency.

[0072] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A highly transparent PE plastic film, characterized in that, It comprises the following components in parts by mass: 10-20 parts of LDPE, 40-50 parts of LLDPE, 15-25 parts of HDPE, 20-30 parts of mPE, 15-25 parts of PP, and 2-5 parts of compatibilizer; The compatibilizer comprises EVA and HDPE-g-MAH with a mass ratio of 1:3-3:1; It further comprises 4-(3-aminopropyl)aniline, and the mass ratio of the compatibilizer to 4-(3-aminopropyl)aniline is 4:1-3; The transverse tensile strength is above 49.1 MPa and the longitudinal tensile strength is above 49.9 MPa.

2. The high-transparency PE plastic film according to claim 1, wherein The mass ratio of the EVA to the HDPE-g-MAH is 1:

1.

3. A highly transparent PE plastic film according to claim 1, characterized in that, The mass ratio of the compatibilizer to 4-(3-aminopropyl)aniline is 2:

1.

4. A highly transparent PE plastic film according to claim 1, characterized in that, The LDPE comprises one or both of LDPE2427H and LDPE 2420D; The LLDPE comprises one or both of LLDPE FD 21HN and LLDPE 6218BE; The HDPE comprises one or both of HDPE ME5000 and HDPE 7000F; The mPE comprises one or both of mPE 1018FA and mPE 3518PA.

5. A highly transparent PE plastic film according to claim 1, characterized in that, The PP comprises one or both of PP DJ-560S and PP J-550S.

6. A method for preparing a highly transparent PE plastic film according to any one of claims 1 to 5, characterized in that, It comprises the following steps: After mixing the components evenly, process and form them to obtain a highly transparent PE plastic film.

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