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CN-121991435-A - Matting agent for BOPE matting film, BOPE matting film and preparation method thereof

CN121991435ACN 121991435 ACN121991435 ACN 121991435ACN-121991435-A

Abstract

The invention belongs to the technical field of biaxially oriented polyethylene extinction films, and relates to an extinction material for a BOPE extinction film and a preparation method thereof, wherein the extinction material comprises a first component, a second component and optional auxiliary agents; the first component comprises a first polyethylene resin, a second polyethylene resin and an optional cycloolefin resin, the second component comprises a polypropylene resin and an optional nucleating agent, and the matting agent comprises at least one of the cycloolefin resin and the nucleating agent. The BOPE extinction film prepared by using the extinction material has high haze and low glossiness, and the whole film has good extinction uniformity.

Inventors

  • LU HONGCHAO
  • XU MENG
  • XU KAI
  • SHI HONGWEI
  • GAO DALI

Assignees

  • 中国石油化工股份有限公司
  • 中石化(北京)化工研究院有限公司

Dates

Publication Date
20260508
Application Date
20241106

Claims (20)

  1. 1. The matting agent for the BOPE matting film is characterized by comprising a first component, a second component and an optional auxiliary agent; The first component includes a first polyethylene resin, a second polyethylene resin, and optionally a cycloolefin resin; The second component comprises a polypropylene resin and optionally a nucleating agent; The matting agent includes at least one of the cycloolefin resin and the nucleating agent.
  2. 2. A matting agent for BOPE matting films according to claim 1, wherein the content of the first component is from 30 to 70wt% and the content of the second component is from 30 to 70wt%, based on the sum of the weights of the first component and the second component; The content of the auxiliary agent is 0 to 0.8wt%, preferably 0.2 to 0.8wt%, based on the sum of the weights of the first component and the second component; the first polyethylene resin is present in an amount of 10 to 30wt%, the second polyethylene resin is present in an amount of 55 to 85wt% and the cycloolefin resin is present in an amount of 0 to 15wt%, preferably 5 to 15wt%, based on the total weight of the first component; The polypropylene resin is present in an amount of 99 to 100wt%, preferably 99 to 99.9wt% and the nucleating agent is present in an amount of 0 to 1wt%, preferably 0.1 to 1wt%, based on the total weight of the second component.
  3. 3. The matting agent for a BOPE matting film according to claim 1 or 2, wherein the first polyethylene resin is a low-density polyethylene and/or a linear low-density polyethylene, the melt index of the first polyethylene resin at 190 ℃ under 2.16kg is 0.5-2g/10min, the density of the first polyethylene resin is 0.916g/cm 3 -0.924g/cm 3 ; The second polyethylene resin is low-density polyethylene and/or linear low-density polyethylene, the melt index of the second polyethylene resin at 190 ℃ and 2.16kg is 20-70g/10min, and the density of the second polyethylene resin is 0.924g/cm 3 -0.930g/cm 3 .
  4. 4. The matting agent for BOPE matting films according to claim 1 or 2, wherein the cycloolefin resin is a cycloolefin copolymer and/or a cycloolefin homopolymer; Preferably, the glass transition temperature of the cycloolefin resin is lower than 110 ℃.
  5. 5. The matting agent for BOPE matting films of claim 1 or 2, wherein the polypropylene resin is homo-polypropylene and/or binary co-polypropylene; Preferably, the density of the polypropylene resin is 0.89g/cm 3 -0.91g/cm 3 , the melt index of the polypropylene resin at 230 ℃ and 2.16kg is 0.1-2g/10min, and the melting point of the polypropylene resin is more than 160 ℃; preferably, the binary copolymer polypropylene is ethylene propylene copolymer or propylene butyl copolymer polypropylene.
  6. 6. A matting agent for BOPE matting films according to claim 1 or 2, wherein the nucleating agent is at least one of sorbitol derivatives, metal salts of organic carboxylic acids, amides, organic phosphates and organic phosphates.
  7. 7. A matting agent for BOPE matt films according to claim 1 or 2, wherein the absolute value of the difference between the crystallization temperature of the second component and the melting point of the first component is less than 8.1 ℃, preferably less than 5 ℃.
  8. 8. A matting agent for BOPE matting films according to claim 1, wherein the auxiliary agent is an antioxidant; Preferably, the antioxidant is antioxidant 1010 and/or antioxidant 168; Further preferably, the antioxidant consists of an antioxidant 1010 and an antioxidant 168, and the mass ratio of the antioxidant 1010 to the antioxidant 168 is (1-4): 1.
  9. 9. The method for preparing the matting agent for the BOPE matting film according to any one of claims 1 to 8, which is characterized in that the method comprises the steps of mixing, extruding, granulating and drying the first component, the second component and optional auxiliary agents to obtain the matting agent for the BOPE matting film; preferably, the preparation method comprises the steps of mixing, extruding, granulating and drying the first component granules, the second component granules and optional auxiliary agents to obtain the matting agent for the BOPE matting film.
  10. 10. The preparation method of the first component pellet according to claim 9, wherein the preparation method of the first component pellet comprises the steps of mixing, extruding, granulating and drying the components of the first component to obtain the first component pellet; preferably, the first component granules are prepared, wherein the mixing time is 1-10min, and the extrusion temperature is 180-250 ℃; When the second component comprises a polypropylene resin and a nucleating agent, the method for preparing the second component pellet comprises the steps of mixing, extruding, granulating and drying the components of the second component to obtain a second component pellet; Preferably, in preparing the second component pellets, the mixing time is 1-10min and the extrusion temperature is 180-250 ℃.
  11. 11. The method of claim 9, wherein the extrusion temperature is 180-250 ℃.
  12. 12. A BOPE extinction film is characterized by comprising a first surface layer, an intermediate layer and a second surface layer in sequence; At least one surface layer of the first surface layer and the second surface layer is a extinction layer; At least one of the first skin layer and the second skin layer is produced from the matting agent for BOPE matting films according to any one of claims 1 to 8.
  13. 13. A BOPE matt film according to claim 12, wherein the intermediate layer is a smooth layer; The middle layer is made of polyethylene resin for BOPE films.
  14. 14. A BOPE matt film according to claim 12, wherein the absolute value of the difference between the melt index of the polymer resin raw material used to make the intermediate layer and the resin raw material used to make the surface layer is less than or equal to 2 at 190 ℃ at 2.16 kg.
  15. 15. A BOPE matt film according to claim 12, wherein the BOPE matt film has a haze of greater than 90% and an absolute value of the difference between the haze values of any two points per square meter of the BOPE matt film is less than 3, preferably less than 1; The gloss of the BOPE matt film is less than 10% and the absolute value of the difference between the gloss values at any two points of the BOPE matt film per square meter is less than 3.1, preferably less than 0.5.
  16. 16. A BOPE matt film according to claim 12, wherein said matt layer thickness is 1.3 to 4 μm; The thickness of the intermediate layer is 9-25 mu m.
  17. 17. A BOPE matting film prepared from a raw material comprising the matting agent for a BOPE matting film according to any one of claims 1 to 8; The haze of the BOPE extinction film is more than 90%, and the absolute value of the difference between the haze values of any two points of the BOPE extinction film per square meter is less than 3, preferably less than 1; The gloss of the BOPE matt film is less than 10% and the absolute value of the difference between the gloss values at any two points of the BOPE matt film per square meter is less than 3.1, preferably less than 0.5.
  18. 18. A BOPE matt film according to claim 17, wherein said BOPE matt film comprises, in order, a first skin layer, an intermediate layer and a second skin layer; At least one surface layer of the first surface layer and the second surface layer is a extinction layer; Preferably, the intermediate layer is a light surface layer.
  19. 19. A process for producing a BOPE matt film as claimed in any of claims 12 to 18, comprising: And then sequentially carrying out longitudinal stretching preheating, longitudinal stretching, transverse stretching preheating, transverse stretching and shaping on the cast sheet to obtain the BOPE extinction film.
  20. 20. The production method according to claim 19, wherein the temperature of the longitudinal stretching preheating is 110 to 130 ℃, the temperature of the longitudinal stretching is 110 to 130 ℃, and the longitudinal stretching magnification is 3 to 6; the temperature of the transverse stretching preheating is 115-135 ℃, the temperature of the transverse stretching is 115-135 ℃, and the transverse stretching multiplying power is 5-10; The shaping temperature is 115-135 ℃.

Description

Matting agent for BOPE matting film, BOPE matting film and preparation method thereof Technical Field The invention relates to the technical field of biaxially oriented polyethylene extinction films, in particular to an extinction material for a BOPE extinction film, the BOPE extinction film and a preparation method thereof. Background Biaxially oriented polyethylene film (BOPE) is obtained by synchronous or asynchronous stretching of a polyethylene casting sheet in both longitudinal and transverse directions, respectively. After stretching, the molecular chains and the platelets of the polyethylene are highly oriented along the stretching direction, so that the BOPE film has the characteristics of high tensile strength, good transparency, low temperature resistance, puncture resistance, impact resistance, easy tearing and few pinhole defects, and is widely applied to the fields of agricultural greenhouse films, composite bags, low-temperature packaging, medical packaging and the like. The BOPE film has excellent performance, can well widen the application field of the plastic film, caters to the trend of light weight and environmental protection of packaging, and has wide market prospect. However, there is a growing need for functional BOPE films in the packaging market, with BOPE matt films being particularly favored in the market for use as high value-added, high-end packaging films. The BOPE extinction film is prepared by adding BOPE extinction material on the surface layer of the co-extrusion film, and then biaxially stretching to make the surface of the film have a coarsening structure for generating diffuse reflection effect on light, thereby playing a role of extinction (matte). The extinction film can give people a soft, fashionable and elegant high-grade feel on packaging products, and can also eliminate eye fatigue, so that the BOPE extinction film is more and more widely applied to the packaging field. However, the matting agents for BOPE matting films and BOPE matting film production techniques are not yet mature. Because of the complex biaxial stretching process, matting special materials such as blow molding or casting PE film matting materials, BOPP matting materials and the like are difficult to be applied to the production of BOPE matting films. Therefore, development of a matched BOPE matt film special material according to a BOPE film material and a biaxial stretching process thereof is needed. In the prior art, CN110876264a discloses a biaxially oriented polyethylene multilayer film with a matt surface, which is a matt film prepared by mixing a specific kind of polyethylene and polypropylene in a certain proportion, extrusion casting directly and on a biaxial stretching machine. The raw materials of the extinction layer in the extinction film prepared by the method are extruded and mixed only once in the whole process, and the problem of poor extinction effect caused by uneven mixing and dispersion of polyethylene and polypropylene in the formula possibly exists. In addition, CN 111978625A discloses a matting agent for a BOPE matting film, a preparation method thereof and the BOPE matting film, wherein the matting agent for the BOPE matting film comprises copolymerized polyethylene, polypropylene, a master batch A and a master batch B, the master batch A comprises a master batch matrix and hydrogenated petroleum resin, the master batch B comprises a master batch matrix and a PPA processing aid, the master batch matrix is copolymerized polyethylene, and the obtained BOPE matting film has the highest haze of 87.4% and the lowest glossiness of 8.7%, so that the matting effect is poor. Disclosure of Invention The invention aims to provide a matting agent for a BOPE matting film, the BOPE matting film and a preparation method thereof, the BOPE extinction film prepared by using the extinction material has high haze and low glossiness, and the whole film has good extinction uniformity. In order to achieve the above object, a first aspect of the present invention provides a matting agent for a BOPE matting film, the matting agent comprising a first component, a second component and optionally an auxiliary agent; The first component includes a first polyethylene resin, a second polyethylene resin, and optionally a cycloolefin resin; The second component comprises a polypropylene resin and optionally a nucleating agent; The matting agent includes at least one of the cycloolefin resin and the nucleating agent. The second aspect of the present invention provides a method for preparing the matting agent for BOPE matting films, comprising mixing, extruding, granulating and drying a first component, a second component and optionally an auxiliary agent to obtain the matting agent for BOPE matting films; preferably, the preparation method comprises the steps of mixing, extruding, granulating and drying the first component granules, the second component granules and optional auxiliary agents to obtain th