Crystal-point-free low-gloss matt coating base film and preparation method thereof

Abstract

The invention discloses a crystal-point-free low-gloss matt coating base film which is sequentially composed of an upper surface layer, a core layer and a lower surface layer, the upper surface layer is a matt layer, and the lower surface layer is an anti-sticking layer; the upper surface layer is prepared from the following raw materials in parts by mass: 1 to 3 parts of modified inorganic matting powder, 0.1 to 0.3 part of antioxidant, 52.2 to 53.5 parts of polypropylene and 44.5 to 45.4 parts of high-density polyethylene. The invention also discloses a preparation method of the crystal-point-free low-gloss matt coating base film. The matt coating base film has the characteristics of low gloss and high haze, is excellent in matt effect, good in mechanical property, free of large-particle crystal point impurities on the surface of the film, and excellent in appearance quality.

Description

Technical Field

[0001] The invention relates to the technical field of thin films, in particular to a low-gloss matte coating base film without crystal points and a preparation method thereof. Background Art

[0002] Matt coating base film is a film for coating with matting effect. As a base film, it has the characteristics of low gloss and can directly give the coated film a matting effect. It is mainly used in industries and fields of deep processing such as coating and lamination. This requires that the matt coating base film should not only provide mechanical support, but also ensure a good matt effect. With the improvement of people's requirements for the appearance and performance of film products, it is necessary to improve the performance of matt coating film products, and the main direction of improvement is to improve the quality of matt coating base film, including eliminating the large particle crystal point defects on the surface of the base film, improving the appearance of the base film surface and the uniformity of the matt effect; or improving the flatness of the matt coating base film to make it more suitable for coating, etc. Among them, crystal point is a common problem in BOPP film processing. It is an over-polymerized high-melting point polymer, which is a product formed by long-term heating under high temperature during the raw material processing. The presence of large particle crystal points will not only significantly affect the appearance of the film surface, but also reduce the matt uniformity for the matt coating base film. Therefore, for matte coating film products that require higher appearance quality, it is crucial to reduce the large particle crystal point defects of the coating base film. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a low-gloss matte coating base film without crystal points and a preparation method thereof.

[0004] The present invention provides a low-gloss matte coating base film without crystal points, which is composed of an upper surface layer, a core layer and a lower surface layer in sequence, wherein the upper surface layer is a matte layer and the lower surface layer is an anti-sticking layer;

[0005] The upper surface layer is made of the following raw materials in parts by weight: 1-3 parts of modified inorganic matting powder, 0.1-0.3 parts of antioxidant, 52.2-53.5 parts of polypropylene, and 44.5-45.4 parts of high-density polyethylene;

[0006] The preparation method of the modified inorganic matting powder comprises the following steps:

[0007] (1) using an aminosilane coupling agent to modify the surface of an inorganic matting powder to obtain an aminosilane-grafted inorganic matting powder; dispersing the aminosilane-grafted inorganic matting powder in xylene, then adding dimethylol propionic acid and a catalyst, heating under reflux and stirring under an inert atmosphere to react, and obtaining a hyperbranched polyester-grafted inorganic matting powder;

[0008] (2) The hyperbranched polyester grafted inorganic matting powder is dispersed in toluene, and then perfluorooctanoic acid and a catalyst are added, and the mixture is heated under reflux and stirred for reaction in an inert atmosphere to obtain a modified inorganic matting powder.

[0009] Preferably, in step (1), the mass ratio of the aminosilane coupling agent to the inorganic matting powder is 1:1-2; preferably, the aminosilane coupling agent is silane coupling agent KH-540, KH-550 or a combination thereof.

[0010] Preferably, in step (1), the specific method of using an aminosilane coupling agent to modify the surface of the inorganic matting powder includes: dispersing the inorganic matting powder in toluene, then adding the aminosilane coupling agent, heating the reaction at 60 to 70° C. for 2 to 4 hours, then filtering, washing and drying the obtained solid matter, and obtaining the product.

[0011] Preferably, in step (1), the mass ratio of the dimethylolpropionic acid to the aminosilane-grafted inorganic matting powder is 1:0.25-1, and the mass ratio of the dimethylolpropionic acid to the catalyst is 100:0.5-1; and the catalyst is p-toluenesulfonic acid.

[0012] In the present invention, after the heating, reflux and stirring reaction in step (1) is completed, conventional subsequent processing steps are also included, including suction filtration, washing and drying.

[0013] Preferably, in step (2), the mass ratio of perfluorooctanoic acid to hyperbranched polyester grafted inorganic matting powder is 1:0.5-1, and the mass ratio of perfluorooctanoic acid to catalyst is 100:2-4; and the catalyst is p-toluenesulfonic acid.

[0014] In the present invention, after the heating, reflux and stirring reaction in step (2) is completed, conventional subsequent processing steps are also included, including suction filtration, washing and drying.

[0015] In the present invention, the inert atmosphere refers to an atmosphere formed by a non-reactive gas, wherein the non-reactive gas may be, for example, nitrogen, argon, or helium.

[0016] Preferably, the polypropylene is a binary or ternary polypropylene copolymer, and the melt index at 230°C and 2.16 kg is 3 to 5 g / 10 min; the density of the high-density polyethylene is 0.920 to 0.961 g / cm 3 The melt index at 230°C and 2.16kg is 0.03-0.08g / 10min.

[0017] Preferably, the inorganic matting powder is silicon dioxide with a particle size of 2 to 5 μm; and the antioxidant is antioxidant 1010, antioxidant 168 or a combination thereof.

[0018] Preferably, the core layer is made of the following raw materials in parts by weight: 99-97 parts of polypropylene and 1-3 parts of antistatic agent; the lower surface layer is made of the following raw materials in parts by weight: 95-99 parts of polypropylene and 1-5 parts of anti-sticking agent.

[0019] Preferably, the anti-sticking agent is Konstanp AB6018PP, and the antistatic agent is antistatic agent PBT.

[0020] Preferably, the matte coating base film has a thickness of 12 to 25 μm, the thickness of the upper surface layer is 2 to 5 μm, and the thickness of the lower surface layer is 0.5 to 2 μm.

[0021] The present invention also proposes a method for preparing the matte coated base film, comprising: adding the raw materials of the core layer into a main extruder and heating and melting them to obtain a core layer melt; adding the raw materials of the upper surface layer and the lower surface layer into two auxiliary extruders and heating and melting them respectively to obtain an upper surface layer melt and a lower surface layer melt; extrude the core layer melt, the upper surface layer melt and the lower surface layer melt together in a die head to obtain a cast sheet; the cast sheet is sequentially cooled, longitudinally stretched and transversely stretched; and then the surface of the upper surface layer is corona treated to a dyne value of 38 to 45 to obtain a matte coated base film.

[0022] Preferably, the heating and melting temperature of the raw materials for the core layer is 247-252°C, the heating and melting temperature of the raw materials for the upper surface layer is 250-258°C, the heating and melting temperature of the raw materials for the lower surface layer is 220-250°C, and the die temperature is 248-255°C.

[0023] Preferably, the longitudinal stretching comprises: preheating at 120-125°C, stretching at a temperature of 115-120°C and a stretching ratio of 4.2-4.6 times, and finalizing at 118-122°C.

[0024] Preferably, the transverse stretching comprises: preheating at 158-162° C., stretching at 151-154° C. and a stretching ratio of 7.5-8.5 times, setting at 156-158° C., and cooling at room temperature.

[0025] The beneficial effects of the present invention are as follows:

[0026] The matte coating base film of the present invention adopts a blend system of polypropylene and high-density polyethylene to form a rough surface of the matte layer, and combines with the addition of inorganic matte powder to achieve a good matte effect, and can achieve a high haze of ≥80% and a gloss of ≤15%, and an excellent appearance quality of low gloss; by grafting the inorganic matte powder surface with hyperbranched polyester, and further fluorination-modifying the hyperbranched polyester, on the one hand, the surface modification of the hyperbranched polyester improves the dispersibility of the inorganic matte powder in the matte layer and the fluidity of the inorganic matte powder, and avoids During processing, inorganic matting powder becomes the core of crystal points due to agglomeration or poor fluidity, which leads to the formation of large-particle crystal points on the surface of the matting layer; on the other hand, the fluorination treatment of hyperbranched polyester on the surface of inorganic matting powder can also improve the lubricity between the melt and the equipment during processing, thereby inhibiting the generation of large-particle crystal points caused by the viscosity of the melt on the surface of the processing equipment; combined with the adjustment of process parameters such as the specific stretching temperature, while ensuring the processing performance and mechanical properties of the film, it is avoided that the polymer is over-polymerized due to excessive processing temperature to produce large-particle crystal points. In summary, the matte coated base film of the present invention has the characteristics of low gloss and high haze, excellent matting effect, good mechanical properties, no large-particle crystal impurities on the surface of the film, and excellent appearance quality. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described in detail below through specific embodiments.

[0028] In the following examples and comparative examples, the melt index of polypropylene at 230°C and 2.16 kg is 3.15 g / 10 min, and the density of high-density polyethylene is 0.920 to 0.961 g / cm 3 The melt index at 230°C and 2.16kg is 0.05g / 10min, the inorganic matting powder is silica with a particle size of 2-5μm, the anti-sticking agent is Constantap AB6018PP, the antioxidant is antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1, and the antistatic agent is antistatic agent PBT.

[0029] Example 1

[0030] A low-gloss matte coating base film without crystal points, which is composed of an upper surface layer, a core layer and a lower surface layer in sequence, wherein the upper surface layer is a matte layer and the lower surface layer is an anti-sticking layer;

[0031] The upper surface layer is made of the following raw materials in parts by weight: 2 parts of modified inorganic matting powder, 0.2 parts of antioxidant, 52.8 parts of polypropylene, and 45 parts of high-density polyethylene;

[0032] The preparation method of the modified inorganic matting powder comprises the following steps:

[0033] (1) dispersing an inorganic matting powder in toluene, then adding a silane coupling agent KH-550, heating and reacting at 60° C. for 4 hours, then filtering, washing and drying the obtained solid matter, and obtaining an aminosilane-grafted inorganic matting powder, wherein the mass ratio of the inorganic matting powder to the silane coupling agent KH-550 is 1:2;

[0034] The inorganic matting powder grafted with aminosilane is dispersed in xylene, and then dimethylolpropionic acid and p-toluenesulfonic acid are added, and the mixture is heated, refluxed, stirred and reacted under a nitrogen atmosphere, and then filtered, and the obtained solid matter is washed and dried to obtain a hyperbranched polyester grafted inorganic matting powder, wherein the mass ratio of dimethylolpropionic acid to the inorganic matting powder grafted with aminosilane is 1:0.25, and the mass ratio of dimethylolpropionic acid to p-toluenesulfonic acid is 100:0.5;

[0035] (2) dispersing the hyperbranched polyester grafted inorganic matting powder in toluene, then adding perfluorooctanoic acid and p-toluenesulfonic acid, heating to reflux and stirring to react under a nitrogen atmosphere, then filtering with suction, washing and drying the obtained solid matter, to obtain a modified inorganic matting powder, wherein the mass ratio of perfluorooctanoic acid to the hyperbranched polyester grafted inorganic matting powder is 1:0.5, and the mass ratio of perfluorooctanoic acid to p-toluenesulfonic acid is 100:2;

[0036] The core layer is made of the following raw materials in parts by weight: 98 parts of polypropylene and 2 parts of antistatic agent; the lower surface layer is made of the following raw materials in parts by weight: 97 parts of polypropylene and 3 parts of anti-sticking agent;

[0037] The thickness of the matte coating base film is 20 μm, the thickness of the upper surface layer is 3.5 μm, and the thickness of the lower surface layer is 1.5 μm.

[0038] The preparation method of the matte coated base film comprises: adding the raw material of the core layer to the main extruder and heating and melting at 247-252° C. to obtain a core layer melt, respectively adding the raw materials of the upper surface layer and the lower surface layer to two auxiliary extruders and heating and melting to obtain an upper surface layer melt and a lower surface layer melt, wherein the heating and melting temperature of the raw material of the upper surface layer is 250-258° C., and the heating and melting temperature of the raw material of the lower surface layer is 220-250° C.; the core layer melt, the upper surface layer melt, and the lower surface layer melt are combined and extruded in a die head to obtain a cast sheet, and the die head temperature is 247-252° C. The casting is sequentially cooled, longitudinally stretched, and transversely stretched, and then the surface of the upper surface layer is corona treated to a dyne value of 42 to obtain a matte coated base film; the longitudinal stretching includes: first preheating at 122°C, then stretching at a temperature of 118°C and a stretching ratio of 4.3 times, and then shaping at 120°C; the transverse stretching includes: first preheating at 160°C, then stretching at a temperature of 153°C and a stretching ratio of 8 times, then shaping at 157°C, and then cooling at room temperature.

[0039] Example 2

[0040] A low-gloss matte coating base film without crystal points, which is composed of an upper surface layer, a core layer and a lower surface layer in sequence, wherein the upper surface layer is a matte layer and the lower surface layer is an anti-sticking layer;

[0041] The upper surface layer is made of the following raw materials in parts by weight: 1 part of modified inorganic matting powder, 0.1 part of antioxidant, 53.5 parts of polypropylene, and 45.4 parts of high-density polyethylene;

[0042] The preparation method of the modified inorganic matting powder comprises the following steps:

[0043] (1) dispersing the inorganic matting powder in toluene, then adding the silane coupling agent KH-550, heating and reacting at 65° C. for 3 h, then filtering, washing and drying the obtained solid matter, and obtaining the aminosilane-grafted inorganic matting powder, wherein the mass ratio of the inorganic matting powder to the silane coupling agent KH-550 is 1:1.5;

[0044] The inorganic matting powder grafted with aminosilane is dispersed in xylene, and then dimethylolpropionic acid and p-toluenesulfonic acid are added, and the mixture is heated, refluxed, stirred and reacted under a nitrogen atmosphere, and then filtered, and the obtained solid matter is washed and dried to obtain a hyperbranched polyester grafted inorganic matting powder, wherein the mass ratio of dimethylolpropionic acid to the inorganic matting powder grafted with aminosilane is 1:0.5, and the mass ratio of dimethylolpropionic acid to p-toluenesulfonic acid is 100:0.8;

[0045] (2) dispersing the hyperbranched polyester grafted inorganic matting powder in toluene, then adding perfluorooctanoic acid and p-toluenesulfonic acid, heating to reflux and stirring to react under a nitrogen atmosphere, then filtering with suction, washing and drying the obtained solid matter, to obtain a modified inorganic matting powder, wherein the mass ratio of perfluorooctanoic acid to the hyperbranched polyester grafted inorganic matting powder is 1:0.6, and the mass ratio of perfluorooctanoic acid to p-toluenesulfonic acid is 100:3;

[0046] The core layer is made of the following raw materials in parts by weight: 98 parts of polypropylene and 2 parts of antistatic agent; the lower surface layer is made of the following raw materials in parts by weight: 97 parts of polypropylene and 3 parts of anti-sticking agent;

[0047] The thickness of the matte coating base film is 20 μm, the thickness of the upper surface layer is 3.5 μm, and the thickness of the lower surface layer is 1.5 μm.

[0048] The preparation method of the above-mentioned matte coating base film is the same as that of Example 1.

[0049] Example 3

[0050] A low-gloss matte coating base film without crystal points, which is composed of an upper surface layer, a core layer and a lower surface layer in sequence, wherein the upper surface layer is a matte layer and the lower surface layer is an anti-sticking layer;

[0051] The upper surface layer is made of the following raw materials in parts by weight: 3 parts of modified inorganic matting powder, 0.3 parts of antioxidant, 52.2 parts of polypropylene, and 44.5 parts of high-density polyethylene;

[0052] The preparation method of the modified inorganic matting powder comprises the following steps:

[0053] (1) dispersing an inorganic matting powder in toluene, then adding a silane coupling agent KH-550, heating the mixture at 70° C. for 2 h, then filtering the mixture, washing and drying the obtained solid matter, and obtaining an aminosilane-grafted inorganic matting powder, wherein the mass ratio of the inorganic matting powder to the silane coupling agent KH-550 is 1:2;

[0054] The inorganic matting powder grafted with aminosilane is dispersed in xylene, and then dimethylolpropionic acid and p-toluenesulfonic acid are added, and the mixture is heated, refluxed, stirred and reacted under a nitrogen atmosphere, and then filtered, and the obtained solid matter is washed and dried to obtain a hyperbranched polyester grafted inorganic matting powder, wherein the mass ratio of dimethylolpropionic acid to the inorganic matting powder grafted with aminosilane is 1:1, and the mass ratio of dimethylolpropionic acid to p-toluenesulfonic acid is 100:1;

[0055] (2) dispersing the hyperbranched polyester grafted inorganic matting powder in toluene, then adding perfluorooctanoic acid and p-toluenesulfonic acid, heating to reflux and stirring to react under a nitrogen atmosphere, then filtering with suction, washing and drying the obtained solid matter, to obtain a modified inorganic matting powder, wherein the mass ratio of perfluorooctanoic acid to the hyperbranched polyester grafted inorganic matting powder is 1:1, and the mass ratio of perfluorooctanoic acid to p-toluenesulfonic acid is 100:4;

[0056] The core layer is made of the following raw materials in parts by weight: 98 parts of polypropylene and 2 parts of antistatic agent; the lower surface layer is made of the following raw materials in parts by weight: 97 parts of polypropylene and 3 parts of anti-sticking agent;

[0057] The thickness of the matte coating base film is 20 μm, the thickness of the upper surface layer is 3.5 μm, and the thickness of the lower surface layer is 1.5 μm.

[0058] The preparation method of the above-mentioned matte coating base film is the same as that of Example 1.

[0059] Comparative Example 1

[0060] A low-gloss matte coating base film without crystal points, which is composed of an upper surface layer, a core layer and a lower surface layer in sequence, wherein the upper surface layer is a matte layer and the lower surface layer is an anti-sticking layer;

[0061] The upper surface layer is made of the following raw materials in parts by weight: 2 parts of inorganic matting powder, 0.2 parts of antioxidant, 52.8 parts of polypropylene, and 45 parts of high-density polyethylene;

[0062] The core layer is made of the following raw materials in parts by weight: 98 parts of polypropylene and 2 parts of antistatic agent; the lower surface layer is made of the following raw materials in parts by weight: 97 parts of polypropylene and 3 parts of anti-sticking agent;

[0063] The thickness of the matte coating base film is 20 μm, the thickness of the upper surface layer is 3.5 μm, and the thickness of the lower surface layer is 1.5 μm.

[0064] The preparation method of the above-mentioned matte coating base film is the same as that of Example 1.

[0065] Comparative Example 2

[0066] A low-gloss matte coating base film without crystal points, which is composed of an upper surface layer, a core layer and a lower surface layer in sequence, wherein the upper surface layer is a matte layer and the lower surface layer is an anti-sticking layer;

[0067] The upper surface layer is made of the following raw materials in parts by weight: 2 parts of hyperbranched polyester grafted inorganic matting powder, 0.2 parts of antioxidant, 52.8 parts of polypropylene, and 45 parts of high-density polyethylene;

[0068] The preparation method of hyperbranched polyester grafted inorganic matting powder comprises the following steps:

[0069] The inorganic matting powder is dispersed in toluene, and then the silane coupling agent KH-550 is added, and the mixture is heated at 60°C for reaction for 4 hours, and then the solid matter is filtered, washed and dried to obtain the aminosilane-grafted inorganic matting powder, wherein the mass ratio of the inorganic matting powder to the silane coupling agent KH-550 is 1:2;

[0070] The inorganic matting powder grafted with aminosilane is dispersed in xylene, and then dimethylolpropionic acid and p-toluenesulfonic acid are added, and the mixture is heated, refluxed, stirred and reacted under a nitrogen atmosphere, and then filtered, and the obtained solid matter is washed and dried to obtain a hyperbranched polyester grafted inorganic matting powder, wherein the mass ratio of dimethylolpropionic acid to the inorganic matting powder grafted with aminosilane is 1:0.25, and the mass ratio of dimethylolpropionic acid to p-toluenesulfonic acid is 100:0.5;

[0071] The core layer is made of the following raw materials in parts by weight: 98 parts of polypropylene and 2 parts of antistatic agent; the lower surface layer is made of the following raw materials in parts by weight: 97 parts of polypropylene and 3 parts of anti-sticking agent;

[0072] The thickness of the matte coating base film is 20 μm, the thickness of the upper surface layer is 3.5 μm, and the thickness of the lower surface layer is 1.5 μm.

[0073] The preparation method of the above-mentioned matte coating base film is the same as that of Example 1.

[0074] Test example

[0075] The matte coated base films of Example 1 and Comparative Examples 1-2 were tested for performance, wherein the haze was tested in accordance with GB / T2410-2008, and the glossiness of the matte layer was tested in accordance with GBT 8807-1988. The method for counting crystal points was as follows: 5 areas of 150 m×150 m were randomly observed and counted on the surface of the matte layer of the film, and the total number of crystal points larger than 0.4 mm in these 5 areas was recorded. The test results are shown in Table 1:

[0076] Table 1

[0077] Haze(%) Glossiness (45°) (%) Number of crystal points Example 1 82 10 0 Comparative Example 1 80 12 8 Comparative Example 2 81 9 5

[0078] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A low gloss matte coating base film without crystal points, characterized in that: It is composed of an upper surface layer, a core layer and a lower surface layer in sequence, wherein the upper surface layer is a matte layer and the lower surface layer is an anti-sticking layer; The upper surface layer is made of the following raw materials in parts by weight: 1-3 parts of modified inorganic matting powder, 0.1-0.3 parts of antioxidant, 52.2-53.5 parts of polypropylene, and 44.5-45.4 parts of high-density polyethylene; The preparation method of the modified inorganic matting powder comprises the following steps: (1) using an aminosilane coupling agent to modify the surface of an inorganic matting powder to obtain an aminosilane-grafted inorganic matting powder; dispersing the aminosilane-grafted inorganic matting powder in xylene, then adding dimethylol propionic acid and a catalyst, heating under reflux and stirring under an inert atmosphere to react, and obtaining a hyperbranched polyester-grafted inorganic matting powder; (2) The hyperbranched polyester grafted inorganic matting powder is dispersed in toluene, and then perfluorooctanoic acid and a catalyst are added, and the mixture is heated under reflux and stirred for reaction in an inert atmosphere to obtain a modified inorganic matting powder.

2. The crystal-free low-gloss matte coating base film according to claim 1, characterized in that: In step (1), the mass ratio of the dimethylolpropionic acid to the aminosilane-grafted inorganic matting powder is 1:0.25-1, and the mass ratio of the dimethylolpropionic acid to the catalyst is 100:0.5-1; and the catalyst is p-toluenesulfonic acid.

3. The crystal point-free low-gloss matte coating base film according to claim 1, characterized in that: In step (2), the mass ratio of perfluorooctanoic acid to hyperbranched polyester grafted inorganic matting powder is 1:0.5-1, and the mass ratio of perfluorooctanoic acid to catalyst is 100:2-4; and the catalyst is p-toluenesulfonic acid.

4. The crystal point-free low-gloss matte coating base film according to claim 1, characterized in that: The polypropylene is a binary or ternary polypropylene copolymer, and the melt index at 230°C and 2.16 kg is 3-5 g / 10 min; the density of the high-density polyethylene is 0.920-0.961 g / cm 3 The melt index at 230°C and 2.16kg is 0.03-0.08g / 10min.

5. The crystal-free low-gloss matte coating base film according to claim 1, characterized in that: The inorganic matting powder is silicon dioxide with a particle size of 2 to 5 μm; the antioxidant is antioxidant 1010, antioxidant 168 or a combination thereof.

6. The crystal-free low-gloss matte coating base film according to claim 1, characterized in that: The core layer is made of the following raw materials in parts by weight: 99-97 parts of polypropylene and 1-3 parts of antistatic agent; the lower surface layer is made of the following raw materials in parts by weight: 95-99 parts of polypropylene and 1-5 parts of anti-sticking agent.

7. The crystal-free low-gloss matte coating base film according to claim 6, characterized in that: The anti-sticking agent is Konstanp AB6018PP, and the antistatic agent is antistatic agent PBT.

8. The matte coating base film according to claim 1, characterized in that: The matte coating base film has a thickness of 12 to 25 μm, the upper surface layer has a thickness of 2 to 5 μm, and the lower surface layer has a thickness of 0.5 to 2 μm.

9. A method for preparing a matte coating base film according to any one of claims 1 to 8, characterized in that: include: The raw materials of the core layer are added to the main extruder and heated and melted to obtain a core layer melt. The raw materials of the upper surface layer and the lower surface layer are respectively added to two auxiliary extruders and heated and melted to obtain an upper surface layer melt and a lower surface layer melt. The core layer melt, the upper surface layer melt and the lower surface layer melt are combined and extruded in a die head to obtain a cast sheet. The cast sheet is sequentially cooled, longitudinally stretched and transversely stretched, and then the surface of the upper surface layer is corona treated to a dyne value of 38 to 45 to obtain a matte coated base film.

10. The method for preparing a matte coating base film according to claim 9, characterized in that: The heating and melting temperature of the raw materials of the core layer is 247-252°C, the heating and melting temperature of the raw materials of the upper surface layer is 250-258°C, the heating and melting temperature of the raw materials of the lower surface layer is 220-250°C, and the die temperature is 248-255°C; The longitudinal stretching comprises: preheating at 120-125°C, stretching at 115-120°C and a stretching ratio of 4.2-4.6 times, and finalizing at 118-122°C; The transverse stretching includes: preheating at 158-162° C., stretching at 151-154° C. and a stretching ratio of 7.5-8.5 times, setting at 156-158° C., and cooling at room temperature.