High-transparency tear-resistant plastic uptake film and preparation method thereof

Abstract

The invention discloses a high-transparency tear-resistant plastic uptake film and a preparation method thereof. The transparency and tear resistance of the prepared plastic uptake film are greatly improved. The plastic uptake film comprises an A / B / A three-layer structure, and the upper surface layer and the lower surface layer of the A layer are arranged on the two sides of the B layer. The mass percent of the NPG modified PET in the A is 91.3%-94.6%, the mass percent of the anti-blocking agent is 1.2%-1.5%, the mass percent of the blocking agent is 2.2%-3.2%, the mass percent of the antistatic agent is 0.5%-1.0%, and the mass percent of the lubricant is 1.5%-3.0%; in the B layer, the mass percent of the PETG is 57.5%-79%, the mass percent of the PET is 20.0%-40.0%, the mass percent of the plasticizer is 0.5%-1.0%, and the mass percent of the flexibilizer is 0.5%-1.5%.

Description

Technical Field

[0001] The invention relates to the field of blister films, in particular to a highly transparent tear-resistant blister film and a preparation method thereof. Background Art

[0002] With the development of social economy and people's higher and higher requirements for packaging quality, high-toughness blister film, as an important packaging material, has shown a steady growth in the market. Blister is a plastic processing technology. The main principle is to heat and soften the flat plastic hard sheet, and then use vacuum adsorption on the surface of the mold (building materials, metals, cardboard, etc.). After cooling, it is adsorbed on the mold. Generally, glue is used between the mold and the film. Blister molding is one of the main ways of plastic molding. Because it has the properties of light weight and good sealing of molding materials. It can package various special-shaped materials and is widely used in the packaging of various products in medical, agricultural, architectural decoration, industrial production and daily life. Since blister molding can achieve packaging with different styles and rich styles through different mold shape designs, it has unique appeal and a huge sales market in today's pursuit of material and cultural diversity.

[0003] Blister packaging materials are the main raw materials for packaging production. Commonly used blister packaging materials include polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG), etc. PET is a semi-crystalline thermoplastic polymer with low cost, excellent mechanical properties, outstanding electrical insulation properties, and good heat resistance and corrosion resistance. Therefore, it is widely used in fields such as fibers, films, and beverage bottles. However, the crystallization rate of PET is slow during processing. When used in plastic molding methods such as injection molding and blister molding, it has the disadvantages of high molding temperature, long molding cycle, and poor dimensional stability, which seriously affects its application and development in engineering plastics. PP material is particularly soft, has good toughness, is environmentally friendly and non-toxic, and is resistant to high temperatures. It is often made into packaging for catering utensils or other high-temperature resistant products; but its plasticity is poor, processing is difficult, the surface gloss is poor, and the color will become lighter during processing. PVC is a commonly used blister packaging material. It has no fixed melting point and a low softening point. The processing temperature is low during the blister molding process and the cooling molding is fast. However, after the blister molding process reaches a certain temperature, the shape is easy to shrink and the temperature resistance is poor. In addition, PVC is the main source of dioxins. When PVC is produced, recycled, destroyed in incinerators, or buried, dioxins will be produced, which will cause serious harm to the health of humans and animals and the environment. PS blister materials have low density (lightweight), are environmentally friendly and non-toxic, have very good plasticity, poor toughness and are brittle. They cannot be made into transparent materials, so they can only be made into bottom support blister. Because they are easy to crack, this type of blister is not suitable for recycling. As a copolyester material, PETG has many excellent properties such as excellent thermoforming performance, weather resistance, chemical resistance, etc. In addition, its melting point is lower than that of PET. The processing temperature during the blister molding process is lower than that of PET, and the cooling molding is fast. Its impact strength is 3 to 10 times that of modified polyacrylates, and it has a wide processing range, high mechanical strength and excellent flexibility. Compared with PVC, it has high transparency, good gloss, easy printing and has the advantage of being green and environmentally friendly. However, the PETG film is easy to tear and break during use after blister molding.

[0004] In order to avoid the deterioration of the contents of the package and maintain its function and performance, when using traditional blister materials for packaging, there are problems such as low transparency, poor flexibility, poor tear resistance, and high cost of blister sheets. Therefore, it is urgent to develop a blister packaging film with high transparency, high toughness, green environmental protection, and low cost. Therefore, the development of high-toughness blister film has important theoretical and practical significance and broad market application prospects. Summary of the invention

[0005] In view of the defects and shortcomings of the prior art, the present invention provides a highly transparent tear-resistant blister film and a preparation method thereof. The present invention can effectively improve the transparency and tear resistance of the prepared blister film, thereby improving the problems of poor gloss and poor toughness of the blister film during the application process, thereby improving the application effect and production efficiency.

[0006] The purpose of the present invention is achieved through the following technical solutions: The invention provides a highly transparent tear-resistant blister film, comprising an A / B / A three-layer structure, which is composed of an A surface layer and a B core layer, wherein the upper and lower surface layers of the A layer are arranged on both sides of the B layer, the A surface layer adopts NPG-modified PET polyester chips, an opening agent, a barrier agent, an antistatic agent and a lubricant; the B core layer adopts PET, PETG, a toughening agent and a plasticizer, the bidirectional strength of the blister film is greater than 90MPa, and the bidirectional fracture productivity is greater than 200%.

[0007] Furthermore, in the A layer, the mass percentage of NPG modified PET is 91.3% to 94.6%, the mass percentage of the opening agent is 1.2% to 1.5%, the mass percentage of the barrier agent is 2.2% to 3.2%, the mass percentage of the antistatic agent is 0.5% to 1.0%, and the mass percentage of the lubricant is 1.5% to 3.0%; in the B layer, the mass percentage of PETG is 57.5% to 79%, the mass percentage of PET is 20.0% to 40.0%, the mass percentage of the plasticizer is 0.5% to 1.0%, and the mass percentage of the toughening agent is 0.5% to 1.5%.

[0008] Furthermore, the opening agent is at least one of nano-silicon dioxide or erucic acid amide; the barrier agent is at least one of polyamide or polyimide; the plasticizer is at least one of modified epoxy oleic acid methyl ester, epoxy oleic acid ethyl ester or polymethyl methacrylate; the antistatic agent is fatty alcohol polyoxyethylene ether; the lubricant is at least one of zinc stearate, calcium stearate, fatty amide, high melting point paraffin or polyethylene wax.

[0009] Furthermore, the toughening agent is a masterbatch prepared from at least one of zirconium oxide, aluminum oxide or silicon nitride and PETG.

[0010] The present invention provides a method for preparing the above-mentioned highly transparent tear-resistant blister film, comprising the following steps: Step 1, preparing a toughening agent; first, PETG and at least one of zirconium oxide, aluminum oxide or silicon nitride powders with a toughening effect are measured in a weight percentage of 8:1 and mixed together in a mixer to mix evenly; after mixing evenly, the mixture is sent to a plasticizing device and plasticized in a twin-screw extruder; the plasticized mixture is cut into granular materials to obtain a toughening agent, and the pelletized particles need to be cooled to room temperature; Step 2, after mixing NPG modified PET polyester chips, an opening agent, a barrier agent, an antistatic agent and a lubricant according to metering, adding them to a surface screw extruder, and then filtering through a filter to obtain a layer A melt; Step 3, PET, PETG, toughening agent and plasticizer are mixed according to metering, added into a core layer screw extruder, and then filtered through a filter to obtain a B layer melt; Step 4, compounding the surface layer melt and the core layer melt into an upper surface layer, a lower surface layer and a core layer in a melt distributor; Step 5, through die casting, rapid cooling roll casting, transverse and longitudinal stretching, traction, winding, slitting inspection and packaging, the highly transparent tear-resistant blister film is obtained.

[0011] Furthermore, the temperature of the surface layer screw extruder is 255-295°C, and the extrusion temperature of the surface layer die head is 245-285°C.

[0012] Furthermore, the temperature of the core layer screw extruder is 250-280°C, and the extrusion temperature of the core layer die head is 245-285°C.

[0013] Furthermore, the extrusion mass ratio of the upper surface layer extruder, the lower surface layer extruder and the core layer extruder is 1:1:1~10.

[0014] Furthermore, in the transverse and longitudinal stretching, the transverse stretching is 4.8-5.4 times, the longitudinal stretching is 2.8-3.5 times, the transverse and longitudinal stretching temperatures are controlled at 88-95°C, and the transverse and longitudinal shaping temperatures are controlled at 84-88°C.

[0015] The present invention also provides application of the above-mentioned highly transparent tear-resistant blister film.

[0016] Beneficial effects: (1) The highly transparent tear-resistant blister film prepared by the present invention has good mechanical properties. The film has excellent bidirectional toughness and a bidirectional strength greater than 90 MPa. It is less likely to be damaged than ordinary blister films, thereby reducing the defective product generation rate at the application end. The film has high bidirectional elongation performance and a bidirectional fracture productivity greater than 200%. During the blister process, the film will not have stress whitening, cold lines or whitening, thus solving the aesthetic problem of the blister process.

[0017] (2) The highly transparent tear-resistant blister film prepared in this application has a higher crystallinity than PETG heat shrinkable film under the combined effect of the formula and stretching process, and has better elongation performance than PET blister film. The melting point of the film is in the middle. The blister film can use a lower processing temperature than ordinary blister film, and the processing time is shortened, which is beneficial to energy saving and consumption reduction in product application. Through the combination of toughening agent and stretching process, the crystallinity of the film is improved. Under the effect of higher crystallinity, the product size of the blister film is more stable and less prone to shrinkage or deformation. Through the effect of antistatic agent and lubricant, the film is easier to separate from the blister during the blister process, and the product surface is smooth and less prone to dents or uneven gloss. Barrier agent can improve the barrier properties of the film, thereby increasing the air and moisture barrier properties of the film to a certain extent, extending the shelf life of the product, etc. DETAILED DESCRIPTION

[0018] Raw materials used in the embodiments and comparative examples: PETG is SKYGREEN ® S2012, Eastman GN071 or Eastman 0603. NPG modified PET is Yuanhong Polymer YH101 or Jiangyin Huahong Chemical Fiber WS501. PET is Yizheng Chemical Fiber BG80, Yizheng Chemical Fiber FG600 or Yuanhong Polymer YH600.

[0019] Preparation of the toughening agent used: First, PETG and at least one of toughening zirconium oxide, aluminum oxide or silicon nitride powder are measured in a weight percentage of 8:1 and mixed together in a mixer to mix evenly; after mixing evenly, the mixture is sent to a plasticizing device and plasticized in a twin-screw extruder; the plasticized mixture is cut into granular materials to obtain a toughening agent, and the pelletized particles need to be cooled to room temperature.

[0020] The opening agent is at least one of nano-silicon dioxide or erucic acid amide; the barrier agent is at least one of polyamide or polyimide; the plasticizer is at least one of modified epoxy methyl oleate, epoxy ethyl oleate or polymethyl methacrylate; the antistatic agent is fatty alcohol polyoxyethylene ether; the lubricant is at least one of zinc stearate, calcium stearate, fatty amide, high melting point paraffin or polyethylene wax.

[0021] Example 1 A highly transparent tear-resistant blister film, comprising an A / B / A three-layer structure, consisting of an A surface layer and a B core layer, wherein the upper and lower surface layers of the A layer are arranged on both sides of the B layer, wherein the raw materials of each layer are: A-Surface layer: The mass percentage of NPG modified PET is 93.0% (intrinsic viscosity, 0.68-0.74 dl / g), the mass percentage of the opening agent is 1.4%, the mass percentage of the barrier agent is 2.4%, the mass percentage of the antistatic agent is 0.8%, and the mass percentage of the lubricant is 2.4%.

[0022] B-core layer: the mass percentage of PETG is 79% (intrinsic viscosity, 0.78-0.82 dl / g), the mass percentage of PET is 20.0% (intrinsic viscosity, 0.62-0.68 dl / g), the mass percentage of plasticizer is 0.5%, and the mass percentage of toughening agent is 0.5%.

[0023] Its preparation process: The raw materials of each layer are mixed in proportion and melted separately, and a multi-layer melt is obtained by multi-layer co-extrusion using a screw extruder, and then the multi-layer melt is formed by die casting and rapid cooling roller cooling to form a cast sheet; the cast sheet is preheated in a longitudinal stretching device, and then longitudinally stretched, and then cooled to shape after longitudinal stretching; after shaping, it is preheated in a transverse stretching device, and then transversely stretched, and then cooled to shape after transverse stretching; thickness measurement, edge trimming, winding, slitting and rewinding, and packaging are performed, so as to obtain a highly transparent and tear-resistant blister film.

[0024] The extrusion mass ratio of the upper surface layer extruder, the lower surface layer extruder and the core layer extruder is 9:9:82.

[0025] The surface layer melt extrusion temperature is controlled at 270°C, the core layer melt extrusion temperature is controlled at 275°C, the die head temperature is 280°C, the transverse stretching ratio is controlled at 4.9 times, the longitudinal stretching ratio is 3.2 times, the transverse and longitudinal stretching temperatures are controlled at 88°C, the transverse and longitudinal shaping temperatures are controlled at 85°C, and the measured thickness is controlled at 50μm.

[0026] Example 2 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: A-Surface layer: The mass percentage of NPG modified PET is 94.6% (intrinsic viscosity, 0.68-0.74 dl / g), the mass percentage of the opening agent is 1.2%, the mass percentage of the barrier agent is 2.2%, the mass percentage of the antistatic agent is 0.5%, and the mass percentage of the lubricant is 1.5%.

[0027] B-core layer: the mass percentage of PETG is 57.5% (intrinsic viscosity, 0.78-0.82 dl / g), the mass percentage of PET is 40.0% (intrinsic viscosity, 0.62-0.68 dl / g), the mass percentage of plasticizer is 1.0%, and the mass percentage of toughening agent is 1.5%.

[0028] Its preparation process: The extrusion mass ratio of the upper surface layer extruder, the lower surface layer extruder and the core layer extruder is 15:15:70.

[0029] The raw materials of each layer are mixed in proportion and melted separately, and a multi-layer melt is obtained by multi-layer co-extrusion using a screw extruder, and then the multi-layer melt is formed by die casting and rapid cooling roller cooling to form a cast sheet; the cast sheet is preheated in a longitudinal stretching device, and then longitudinally stretched, and then cooled to shape after longitudinal stretching; after shaping, it is preheated in a transverse stretching device, and then transversely stretched, and then cooled to shape after transverse stretching; thickness measurement, edge trimming, winding, slitting and rewinding, and packaging are performed, so as to obtain a highly transparent and tear-resistant blister film.

[0030] The surface layer melt extrusion temperature is controlled at 272°C, the core layer melt extrusion temperature is controlled at 285°C, the die head temperature is 280°C, the transverse stretching ratio is controlled at 5.2 times, the longitudinal stretching ratio is 3.0 times, the transverse and longitudinal stretching temperatures are controlled at 92°C, the transverse and longitudinal shaping temperatures are controlled at 85°C, and the measured thickness is controlled at 50μm.

[0031] Example 3 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: A-Surface layer: The mass percentage of NPG modified PET is 91.3% (intrinsic viscosity, 0.68-0.74 dl / g), the mass percentage of the opening agent is 1.5%, the mass percentage of the barrier agent is 3.2%, the mass percentage of the antistatic agent is 1.0%, and the mass percentage of the lubricant is 3.0%.

[0032] B-core layer: the mass percentage of PETG is 63.2% (intrinsic viscosity, 0.78-0.82 dl / g), the mass percentage of PET is 35.0% (intrinsic viscosity, 0.62-0.68 dl / g), the mass percentage of plasticizer is 0.8%, and the mass percentage of toughening agent is 1.0%.

[0033] Its preparation process: The extrusion mass ratio of the upper surface layer extruder, the lower surface layer extruder and the core layer extruder is 10:10:80.

[0034] The raw materials of each layer are mixed in proportion and melted separately, and a multi-layer melt is obtained by multi-layer co-extrusion using a screw extruder, and then the multi-layer melt is formed by die casting and rapid cooling roller cooling to form a cast sheet; the cast sheet is preheated in a longitudinal stretching device, and then longitudinally stretched, and then cooled to shape after longitudinal stretching; after shaping, it is preheated in a transverse stretching device, and then transversely stretched, and then cooled to shape after transverse stretching; thickness measurement, edge trimming, winding, slitting and rewinding, and packaging are performed, so as to obtain a highly transparent and tear-resistant blister film.

[0035] The surface layer melt extrusion temperature is controlled at 275°C, the core layer melt extrusion temperature is controlled at 282°C, the die head temperature is 280°C, the transverse stretching ratio is controlled at 5.0 times, the longitudinal stretching ratio is 3.1 times, the transverse and longitudinal stretching temperatures are controlled at 91°C, the transverse and longitudinal shaping temperatures are controlled at 85°C, and the measured thickness is controlled at 50μm.

[0036] Comparative Example 1 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: B-core layer: the mass percentage of PETG is 98.2% (intrinsic viscosity, 0.78-0.82 dl / g), the mass percentage of plasticizer is 0.8%, and the mass percentage of toughening agent is 1.0%.

[0037] The A-surface layer formula and its preparation process are the same as those in Example 3, and will not be described in detail in this comparative example.

[0038] Comparative Example 2 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: B-core layer: the mass percentage of PET is 98.2% (intrinsic viscosity, 0.62-0.68 dl / g), the mass percentage of plasticizer is 0.8%, and the mass percentage of toughening agent is 1.0%.

[0039] The A-surface layer formula and its preparation process are the same as those in Example 3, and will not be described in detail in this comparative example.

[0040] Comparative Example 3 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: B-core layer: the mass percentage of PETG is 63.2% (intrinsic viscosity, 0.78-0.82 dl / g), the mass percentage of PET is 35.0% (intrinsic viscosity, 0.62-0.68 dl / g), and the mass percentage of toughening agent is 1.8%.

[0041] The A-surface layer formula and its preparation process are the same as those in Example 3, and will not be described in detail in this comparative example.

[0042] Comparative Example 4 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: B-core layer: the mass percentage of PETG is 63.2% (intrinsic viscosity, 0.78-0.82 dl / g), the mass percentage of PET is 35.0% (intrinsic viscosity, 0.62-0.68 dl / g), and the mass percentage of plasticizer is 1.8%.

[0043] The A-surface layer formula and its preparation process are the same as those in Example 3, and will not be described in detail in this comparative example.

[0044] Comparative Example 5 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: B-core layer: the mass percentage of PETG is 63.2% (intrinsic viscosity, 0.78-0.82 dl / g), and the mass percentage of PET is 36.8% (intrinsic viscosity, 0.62-0.68 dl / g).

[0045] The A-surface layer formula and its preparation process are the same as those in Example 3, and will not be described in detail in this comparative example.

[0046] Comparative Example 6 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: A-Surface layer: The mass percentage of NPG modified PET is 94.5% (intrinsic viscosity, 0.68-0.74 dl / g), the mass percentage of the anti-blocking agent is 1.5%, the mass percentage of the antistatic agent is 1.0%, and the mass percentage of the lubricant is 3.0%.

[0047] The formula and preparation process of the B-core layer are the same as those in Example 3, and will not be described in detail in this comparative example.

[0048] Comparative Example 7 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: A-Surface layer: The mass percentage of NPG modified PET is 92.3% (intrinsic viscosity, 0.68-0.74 dl / g), the mass percentage of the opening agent is 1.5%, the mass percentage of the barrier agent is 3.2%, and the mass percentage of the lubricant is 3.0%.

[0049] The formula and preparation process of the B-core layer are the same as those in Example 3, and will not be described in detail in this comparative example.

[0050] Comparative Example 8 A highly transparent tear-resistant blister film, comprising a laminated surface layer A and a core layer B, wherein the raw materials of each layer are: A-Surface layer: The mass percentage of NPG modified PET is 94.3% (intrinsic viscosity, 0.68-0.74 dl / g), the mass percentage of the opening agent is 1.5%, the mass percentage of the barrier agent is 3.2%, and the mass percentage of the antistatic agent is 1.0%.

[0051] The formula and preparation process of the B-core layer are the same as those in Example 3, and will not be described in detail in this comparative example.

[0052] Comparative Example 9 A highly transparent tear-resistant blister film, with a preparation process as follows: the surface layer melt extrusion temperature is controlled at 275°C, the core layer melt extrusion temperature is controlled at 282°C, the die head temperature is 280°C, the transverse stretching multiple is controlled at 4.5 times, the longitudinal stretching multiple is 1.5 times, the transverse and longitudinal stretching temperatures are controlled at 91°C, the transverse and longitudinal shaping temperatures are controlled at 85°C, and the measured thickness is controlled at 50μm.

[0053] The formula of the core layer B and the core layer A are the same as those in Example 3, and will not be described in detail in this comparative example.

[0054] Comparative Example 10 A highly transparent tear-resistant blister film, with a preparation process as follows: the surface layer melt extrusion temperature is controlled at 275°C, the core layer melt extrusion temperature is controlled at 282°C, the die head temperature is 280°C, the transverse stretching multiple is controlled at 5.0 times, the longitudinal stretching multiple is 3.1 times, the transverse and longitudinal stretching temperatures are controlled at 82°C, the transverse and longitudinal shaping temperatures are controlled at 75°C, and the measured thickness is controlled at 50μm.

[0055] The B-core layer formula and the A-core layer formula are the same as those in Example 3, and will not be described in detail in this comparative example.

[0056] Table 1 shows the performance test results of the highly transparent tear-resistant blister film obtained in the above examples.

[0057] Table 1 Main performance parameters of high transparent tear-resistant blister film Comparative Example 1 Compared with Example 3, Example 3 adds PET, which improves the overall crystallinity of the film, thereby improving the bidirectional strength (tensile strength) of the film. The film has excellent toughness and is not easily damaged during the blister forming process. The defective rate of the blister forming process can be reduced and the use time of the film after blister forming can be increased.

[0058] Comparative Example 2 Compared with Example 3, Example 3 adds PETG, which increases the bidirectional heat shrinkage performance of the film, improves the flexibility of the film, can meet more complex blister effects, and improves the application range of the film. On the contrary, the blister film without adding PETG film has almost no shrinkage characteristics and cannot meet many blister shape requirements. At the same time, too much crystalline material PET will increase the haze of the film, and the transparency and transmittance of the film cannot meet the requirements.

[0059] Comparative Example 3 Compared with Example 3, Comparative Example 3 does not add a toughening agent. Under the action of the plasticizer, the elongation performance of the film is greatly improved, but the toughness of the blister film, such as tensile strength and elastic modulus, is reduced due to the action of the plasticizer, resulting in insufficient strength of the film after blister forming and easy damage.

[0060] Comparative Example 4 Compared with Example 3, Comparative Example 4 does not add plasticizer, and the biaxial strength of the film is increased, but the elongation performance of the film is insufficient to meet the requirements of the blister of special shapes of the film, which will reduce the application scenarios of the blister film.

[0061] Comparative Example 5 Compared with Example 3, Comparative Example 5 does not add plasticizer and toughening agent, the biaxial strength and elongation performance of the film are not high enough to meet the requirements of the special-shaped blister molding of the film, and the risk of film damage during the blister molding process is increased.

[0062] Comparative Example 6 Compared with Example 3, no barrier agent is added to the surface layer of Comparative Example 6, and the water vapor permeability and oxygen permeability of the film will be higher, which cannot meet the barrier performance requirements required in certain barrier function fields, reducing the application scope of the film.

[0063] Comparative Example 7 Compared with Example 3, the surface layer of Comparative Example 7 does not have an antistatic agent added, and the film is prone to static electricity during the production process. The electrostatic adsorption between the film layers is difficult to separate, which is not conducive to high-speed production and application of the product. At the same time, the film is prone to the problem of difficulty in separating the blister mold during the blister molding process, which requires special processing to reduce production efficiency.

[0064] Comparative Example 8 Compared with Example 3, the surface layer of Comparative Example 8 does not have a lubricant added, and cannot work synergistically with the antistatic agent. The friction between the film layers is large during the production process, which is easy to generate static electricity, which is not conducive to the high-speed production and application of the product. At the same time, after the film is blister-formed, under the action of the lubricant, the blister film is easier to separate from the blister mold, and the friction is reduced, and the blister film is not easy to be scratched.

[0065] Comparative Example 9 Compared with Example 3, in the film-making process of Comparative Example 9, the transverse stretching ratio is controlled to be 4.5 times, and the longitudinal stretching ratio is 1.5 times. In this way, the biaxial stretching ratio of the film is insufficient, and the stretching orientation degree of the film is low, resulting in low crystallinity of the film due to orientation, and a certain degree of reduction in the tensile strength and elastic modulus of the film. As a result, the barrier performance of the film is reduced, and the shrinkage performance of the film is reduced and cannot meet more special-shaped blister requirements.

[0066] Comparative Example 10 Compared with Example 3, in the film making process of Comparative Example 10, the transverse and longitudinal stretching temperatures are controlled at 82°C, and the transverse and longitudinal shaping temperatures are controlled at 75°C. The stretching and shaping temperatures of the film are lower, and the shrinkage performance of the film is better. However, the crystallinity of the film will be reduced after finishing, thereby reducing the toughness of the film. Under the premise that the processing technology is not suitable, the film cannot meet customer requirements.

[0067] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and other functional highly transparent tear-resistant blister films can also be prepared. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A highly transparent tear-resistant blister film, comprising an A / B / A three-layer structure, consisting of an A surface layer and a B core layer, wherein the upper and lower surface layers of the A layer are arranged on both sides of the B layer, characterized in that: The surface layer of layer A adopts NPG modified PET polyester chips, an opening agent, a barrier agent, an antistatic agent and a lubricant; the core layer of layer B adopts PET, PETG, a toughening agent and a plasticizer. The bidirectional strength of the blister film is greater than 90MPa, and the bidirectional fracture productivity is greater than 200%.

2. A highly transparent tear-resistant blister film as claimed in claim 1, characterized in that: The mass percentage of NPG modified PET in the A layer is 91.3% to 94.6%, the mass percentage of the opening agent is 1.2% to 1.5%, the mass percentage of the barrier agent is 2.2% to 3.2%, the mass percentage of the antistatic agent is 0.5% to 1.0%, and the mass percentage of the lubricant is 1.5% to 3.0%; the mass percentage of PETG in the B layer is 57.5% to 79%, the mass percentage of PET is 20.0% to 40.0%, the mass percentage of the plasticizer is 0.5% to 1.0%, and the mass percentage of the toughening agent is 0.5% to 1.5%.

3. A highly transparent tear-resistant blister film as claimed in claim 2, characterized in that: The opening agent is at least one of nano-silicon dioxide or erucic acid amide; the barrier agent is at least one of polyamide or polyimide; the plasticizer is at least one of modified epoxy methyl oleate, epoxy ethyl oleate or polymethyl methacrylate; the antistatic agent is fatty alcohol polyoxyethylene ether; the lubricant is at least one of zinc stearate, calcium stearate, fatty amide, high melting point paraffin or polyethylene wax.

4. A highly transparent tear-resistant blister film as claimed in claim 2, characterized in that: The toughening agent is a masterbatch prepared from at least one of zirconium oxide, aluminum oxide or silicon nitride and PETG.

5. A method for preparing a highly transparent tear-resistant blister film according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, preparing a toughening agent; first, PETG and at least one of zirconium oxide, aluminum oxide or silicon nitride powders with a toughening effect are measured in a weight percentage of 8:1 and mixed together in a mixer to mix evenly; after mixing evenly, the mixture is sent to a plasticizing device and plasticized in a twin-screw extruder; the plasticized mixture is cut into granular materials to obtain a toughening agent, and the pelletized particles need to be cooled to room temperature; Step 2, after mixing NPG modified PET polyester chips, an opening agent, a barrier agent, an antistatic agent and a lubricant according to metering, adding them to a surface screw extruder, and then filtering through a filter to obtain a layer A melt; Step 3, PET, PETG, toughening agent and plasticizer are mixed according to metering, added into a core layer screw extruder, and then filtered through a filter to obtain a B layer melt; Step 4, compounding the surface layer melt and the core layer melt into an upper surface layer, a lower surface layer and a core layer in a melt distributor; Step 5, through die casting, rapid cooling roll casting, transverse and longitudinal stretching, traction, winding, slitting inspection and packaging, the highly transparent tear-resistant blister film is obtained.

6. The method for preparing a highly transparent tear-resistant blister film according to claim 5, characterized in that: The temperature of the surface layer screw extruder is 255-295°C, and the extrusion temperature of the surface layer die head is 245-285°C.

7. The method for preparing a highly transparent tear-resistant blister film according to claim 5, characterized in that: The temperature of the core layer screw extruder is 250-280°C, and the extrusion temperature of the core layer die head is 245-285°C.

8. The method for preparing a highly transparent tear-resistant blister film according to claim 5, characterized in that: The extrusion mass ratio of the upper surface layer extruder, the lower surface layer extruder and the core layer extruder is 1:1:1~10.

9. The method for preparing a highly transparent tear-resistant blister film according to claim 5, characterized in that: In the transverse and longitudinal stretching, the transverse stretching is 4.8-5.4 times, and the longitudinal stretching is 2.8-3.5 times. The transverse and longitudinal stretching temperatures are controlled at 88-95°C, and the transverse and longitudinal shaping temperatures are controlled at 84-88°C.

10. Use of the highly transparent tear-resistant blister film according to any one of claims 1 to 5.

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