PET heat-sealing film capable of blocking infrared rays and ultraviolet rays as well as preparation method and application of PET heat-sealing film

Abstract

The invention belongs to the technical field of PET (polyethylene terephthalate) film materials, and particularly discloses a PET heat-sealing film for blocking infrared rays and ultraviolet rays as well as a preparation method and application of the PET heat-sealing film. The PET heat-sealing film provided by the invention is of a multi-layer film structure and comprises a near-infrared and ultraviolet absorption layer, a transparent layer and a heat-sealing layer, wherein the near-infrared absorption layer and the ultraviolet absorption layer have an absorption effect on near-infrared rays and ultraviolet rays, so that the transmission of invisible light can be reduced, and the blocking effect of the film on radiation can be improved; the transparent layer takes optical-grade transparent PET as a preparation raw material, so that the transparency of the film can be improved, the stiffness of the film can be increased, and the winding effect can be improved; the heat sealing layer can endow the film with self-adhesion, so that the film can be directly compounded with glass at a high temperature, and the use of an adhesive is avoided. In addition, the preparation process of the PET heat-sealing film is simple, the operability is high, industrial production is easy to perform, and the PET heat-sealing film has good application prospects and high economic value.

Description

Technical Field

[0001] The invention belongs to the technical field of PET film materials, and in particular relates to a PET heat-sealing film capable of blocking infrared rays and ultraviolet rays, and a preparation method and application thereof. Background Art

[0002] The UV index is high in summer. Due to the good airtightness of buildings and vehicles, long-term exposure to sunlight will increase the internal temperature, which will cause danger. In order to reduce the radiation transmittance, glass film is usually used to block harmful light. In addition, when the glass is broken by factors such as weather or impact, the flying fragments can easily cause secondary damage to the human body. Therefore, laminated glass is often used in applications, that is, a protective film is added between the two pieces of glass. When the glass is broken, the fragments still adhere to the protective film to ensure personal safety.

[0003] PET polyester film has the advantages of high optical transparency, glossiness, and good dimensional stability. Especially in terms of mechanical properties, its tensile strength is 9 times that of PE film. After biaxial stretching, the tensile strength of BOPET film is 3-5 times that before stretching. It has been widely used in electronics, electrical appliances, automobiles, construction and other fields. However, ordinary PET polyester film cannot block near-infrared and ultraviolet rays, and has poor radiation protection effect. Although the method of coating the surface of the film with a coating liquid to prevent invisible light from passing through is simple, there is no protective layer on the surface of the film, which is easy to damage the film surface. At the same time, ordinary PET polyester film has no adhesive effect when used as a glass film, and needs to be coated on the outside of the film to form an adhesive layer. The use steps are cumbersome and do not conform to the development concept of green environmental protection. To solve this problem, Chinese patent CN104277729B provides a glass film, which is composed of a modified PET base layer and an adhesive layer, wherein the raw materials for preparing the modified PET base layer include PET masterbatch, PE resin, nano-silicon powder, aloe extract, diglycerol, isooctyl palmitate, chitosan and ethylene glycol butyl ether, and the raw materials for preparing the adhesive layer include ethyl acrylate, rosin resin and ethylene glycol. After testing, the glass film has good heat insulation flame retardancy, explosion resistance and UV resistance, but its composition is complex, the process is cumbersome, and an adhesive layer needs to be coated. It is not easy to realize industrial production and the preparation cost is high. Therefore, it is urgent to develop a PET polyester film that is radiation-proof, does not require an adhesive layer, has a simple preparation process, and is low in cost. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The technical problem to be solved by the present invention is to provide a PET heat-sealing film that blocks infrared and ultraviolet rays and a preparation method thereof, so as to solve the problems that ordinary PET polyester films do not have radiation protection and heat-sealing properties, and the improved polyester films have complex components, cumbersome preparation processes, and high production costs. The PET heat-sealing film provided by the present invention has an absorption effect on near-infrared and ultraviolet rays, can effectively reduce the transmission of radiation without affecting the transmission of visible light, and the film body has self-adhesiveness, can be compounded in laminated glass, reduce the use of adhesives and release paper, and conform to the concept of green environmental protection.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A PET heat-sealing film that blocks infrared and ultraviolet rays, which is a multi-layer film structure, including a near-infrared and ultraviolet absorbing layer, a transparent layer, and a heat-sealing layer;

[0009] The raw materials for preparing the near infrared and ultraviolet absorption layers include near infrared absorption masterbatch, ultraviolet absorption masterbatch, and PET polyester chips;

[0010] The raw materials for preparing the transparent layer include high gloss polyester chips;

[0011] The raw material for preparing the heat sealing layer includes PETG masterbatch.

[0012] As a preferred embodiment of the present invention, the near-infrared absorbing masterbatch is a PET-based masterbatch containing a near-infrared absorber, which is prepared by an extrusion granulation process.

[0013] Specifically, the preparation method of the near-infrared absorption masterbatch includes: mixing PET polyester chips and near-infrared absorbers, and preparing the near-infrared absorption masterbatch by extrusion granulation. The near-infrared absorbers include but are not limited to cesium tungsten bronze nanoparticles (Cs x WO3), antimony-doped tin dioxide (ATO), indium tin oxide (ITO), lanthanum hexaboride (LaB6), etc. The amount of the near-infrared absorber is 0.5%-1.0% of the mass of the near-infrared absorber masterbatch. The technical parameters of the extrusion granulation are: extrusion temperature 265-285°C, extruder speed 300-400rpm.

[0014] As a preferred embodiment of the present invention, the ultraviolet absorption masterbatch is a PET-based masterbatch containing an ultraviolet absorber, which is prepared by an extrusion granulation process.

[0015] Specifically, the preparation method of the ultraviolet absorption masterbatch includes: mixing PET polyester chips and ultraviolet absorbers, and preparing the ultraviolet absorption masterbatch by extrusion granulation. The ultraviolet absorber includes but is not limited to one or more of benzotriazole (such as UV-326, UV-327), benzophenone (UV-531) ultraviolet absorbers, etc. The amount of the ultraviolet absorber is 0.5%-1.0% of the mass of the ultraviolet absorption masterbatch. The process parameters of the extrusion granulation are: extrusion temperature 265-285°C, extruder speed 300-400rpm.

[0016] As a preferred embodiment of the present invention, the PET polyester chips are commercially available and can be purchased. For example, the base material polyester chips of Sinopec Yizheng Chemical Fiber Co., Ltd. are mainly suitable for single-point stretch film production lines, and the product brand is FG600.

[0017] As a preferred embodiment of the present invention, the mass ratio of the near-infrared absorption masterbatch, the ultraviolet absorption masterbatch, and the PET polyester chips is 5-10:5-10:80-90.

[0018] As a preferred embodiment of the present invention, the high-gloss polyester chips are commercially available and can be purchased. For example, the base material polyester chips of Sinopec Yizheng Chemical Fiber Co., Ltd. are suitable for producing high-grade optical films, and the product brand is FG604.

[0019] As a preferred embodiment of the present invention, the PETG masterbatch is a commercially available commodity and can be purchased. For example, the functional PETG polyester of Henan Yinjinda New Materials Co., Ltd. is used, and the product brand is: YH-301.

[0020] As a preferred embodiment of the present invention, the multilayer film structure is a five-layer film structure, such as a CBABC five-layer structure, wherein a transparent layer (B layer) is arranged on both sides of the near-infrared and ultraviolet absorption layer (A layer), and a heat sealing layer (C layer) is arranged on the outer side of the transparent layer.

[0021] As a preferred embodiment of the present invention, the thickness of the near-infrared and ultraviolet absorbing layer is 8-32 μm, the thickness of the transparent layer is 3-12 μm, and the thickness of the heat-sealing layer is 1-4 μm.

[0022] A method for preparing a PET heat-sealing film for blocking infrared rays and ultraviolet rays comprises the following steps:

[0023] The raw materials for preparing the near-infrared and ultraviolet absorbing layer, the transparent layer and the heat-sealing layer are fed separately, and are sequentially subjected to melt extrusion, cast film and biaxial stretching treatment to obtain a PET heat-sealing film that blocks infrared and ultraviolet rays.

[0024] As a preferred embodiment of the present invention, the melting temperature of the melt for preparing the near-infrared and ultraviolet absorbing layer is 260-285°C.

[0025] As a preferred embodiment of the present invention, the melting temperature of the melt for preparing the transparent layer is 265-280°C.

[0026] As a preferred embodiment of the present invention, the melting temperature of the melt for preparing the heat sealing layer is 230-285°C.

[0027] As a preferred embodiment of the present invention, in the tape casting process, the temperature of the casting roller is 15-20°C.

[0028] As a preferred embodiment of the present invention, the biaxial stretching treatment is to perform longitudinal stretching and transverse stretching in sequence, and the technical parameters of the longitudinal stretching are: preheating zone temperature 60-110°C, stretching zone temperature 110-120°C, cooling zone temperature 25-40°C, and stretching ratio 3-4 times; the technical parameters of the transverse stretching are: preheating zone temperature 85-100°C, stretching zone temperature 100-160°C, shaping zone temperature 160-230°C, cooling zone temperature 30-50°C, and stretching ratio 3-4 times.

[0029] As a preferred embodiment of the present invention, the biaxial stretching treatment is followed by traction and winding, with a winding speed of 150-300 m / min, followed by slitting and packaging to obtain the PET heat-sealing film.

[0030] A PET heat-sealing film capable of blocking infrared rays and ultraviolet rays is used in the preparation of laminated glass, optical lenses, building thermal insulation materials, etc.

[0031] (III) Beneficial effects

[0032] The infrared and ultraviolet light blocking PET heat-sealing film provided by the present invention is a multi-layer film structure, wherein the near-infrared and ultraviolet light absorbing layer has an absorption effect on near-infrared and ultraviolet light, can reduce the transmission of invisible light, and thus improve the radiation blocking effect of the film; the transparent layer is prepared with optical-grade transparent PET (high-gloss polyester chips), which can not only improve the transparency of the film, but also increase the stiffness of the film and improve the winding effect; the heat-sealing layer can be directly compounded with glass at high temperature, avoiding the use of film adhesives.

[0033] The PET heat-sealing film provided by the present invention has a simple preparation process and readily available raw materials. When preparing the film, near-infrared absorption masterbatch and ultraviolet absorption masterbatch are added to isolate heat and reduce the penetration of ultraviolet rays, thereby achieving the purpose of reducing the energy exchange inside and outside the film, and making the film have the performance of blocking radiation. In addition, the addition of PETG masterbatch can make the film body have self-adhesiveness, and the use of adhesives and release paper can be reduced for the production of laminated glass, which is in line with the current development concept of green environmental protection. At the same time, the method is highly operable and easy to carry out industrial production. The obtained film material is suitable for preparing laminated glass, optical lenses, building insulation materials, etc., and has good application prospects and high economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of the infrared and ultraviolet blocking PET heat sealing film prepared in Example 1.

[0035] In order to more clearly illustrate the technical solution to be protected by the present invention, the drawings in the embodiments and / or experimental examples are briefly introduced above. It should be understood that the above drawings should not be regarded as any limitation on the protection scope of the present invention. For ordinary technicians in this field, other related drawings can also be obtained based on these drawings without paying creative work. DETAILED DESCRIPTION

[0036] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments and experimental examples. Those skilled in the art should understand that the following embodiments and experimental examples are only used to illustrate the technical scheme and technical effects of the present invention and should not be regarded as any limitation on the protection scope of the present invention. Based on the following embodiments, other technical schemes obtained by ordinary technicians in the field without paying creative labor, such as technical schemes obtained after modification, deformation or simple replacement, all belong to the protection scope of the present invention.

[0037] The raw materials, reagents, equipment, etc. used in the embodiments and experimental examples are all commercially available unless otherwise specified. Among them, PET polyester chips were purchased from Sinopec Yizheng Chemical Fiber Co., Ltd., with the product brand: FG600; Dayouguang polyester chips were purchased from Sinopec Yizheng Chemical Fiber Co., Ltd., with the product brand: FG604; PETG masterbatch was purchased from Henan Yinjinda New Materials Co., Ltd., with the product brand: YH-301.

[0038] The methods used in the embodiments and experimental examples are conventional methods unless otherwise specified.

[0039] The terms and abbreviations used in the embodiments and experimental examples have common meanings in the art.

[0040] Example 1

[0041] This embodiment provides a PET heat-sealing film that blocks infrared and ultraviolet rays, which is a CBABC five-layer film structure (the structural schematic diagram is shown in FIG. Figure 1 As shown in FIG. 1 , a transparent layer (B layer) is disposed on both sides of the near infrared and ultraviolet absorbing layer (A layer), and a heat sealing layer (C layer) is disposed on the outer side of the transparent layer. The thickness of the near infrared and ultraviolet absorbing layer (A layer) is 8 μm, the thickness of the transparent layer (B layer) is 3 μm, and the thickness of the heat sealing layer (C layer) is 1 μm.

[0042] This embodiment also provides a method for preparing a PET heat-sealing film that blocks infrared rays and ultraviolet rays, comprising the following steps:

[0043] The raw materials for preparing the near-infrared and ultraviolet absorbing layers, the near-infrared absorbing masterbatch, the ultraviolet absorbing masterbatch, and the PET polyester chips are added in a mass ratio of 5:5.:90 and fully mixed, added to the main extruder, melt-extruded at 270°C, vacuumed (except small molecules), and filtered into the distribution block to form the main extrusion melt;

[0044] The near infrared absorption masterbatch is a PET-based masterbatch containing a near infrared absorber. The preparation method comprises the following steps: mixing PET polyester chips with cesium tungsten bronze nanoparticles (Cs x WO3) is mixed and extruded by a twin-screw extruder to obtain a masterbatch, the extrusion temperature is 275°C, the extruder speed is 350rpm, and the amount of cesium tungsten bronze nanoparticles is 0.5% of the mass of the masterbatch;

[0045] The ultraviolet absorption masterbatch is a PET-based masterbatch containing an ultraviolet absorber, and the preparation method comprises the following steps: mixing PET polyester chips and benzotriazole ultraviolet absorber UV-326 through a twin-screw extruder to granulate to obtain a masterbatch, the extrusion temperature is 275° C., the extruder speed is 350 rpm, and the amount of UV-326 is 0.5% of the mass of the masterbatch;

[0046] Add the raw material of the transparent layer, the glossy polyester chips, into the auxiliary extrusion first, and after being melt-extruded at 275°C, vacuumized, filtered and then enter the distribution block to obtain the auxiliary extrusion first melt;

[0047] The raw material PETG masterbatch for preparing the heat sealing layer is added to the auxiliary extrusion 2, and after being melt-extruded at 275°C, vacuumed, and filtered, it enters the distribution block to become the auxiliary extrusion 2 melt;

[0048] The above melt extrusion was used to prepare a CBABC five-layer structure, wherein the rotation speeds of the main extruder, the auxiliary extruder one, and the auxiliary extruder two were 67 rpm, 130 rpm, and 186 rpm, respectively. After extrusion, the film was successively subjected to cast film (casting roller temperature 18°C), longitudinal stretching (preheating zone temperature 80°C, stretching zone temperature 115°C, cooling zone temperature 30°C, stretching ratio 4 times), transverse stretching (preheating zone temperature 90°C, stretching zone temperature 120°C, shaping zone temperature 220°C, cooling zone temperature 35°C, stretching ratio 4 times), traction and winding (winding speed of 300 m / min), slitting and packaging to obtain a PET heat-sealing film that blocks infrared and ultraviolet rays.

[0049] This embodiment also provides an application of a PET heat-sealing film that blocks infrared rays and ultraviolet rays in the preparation of laminated glass.

[0050] Example 2

[0051] This embodiment provides a PET heat-sealing film for blocking infrared and ultraviolet rays, which is a CBABC five-layer film structure, wherein a transparent layer (B layer) is provided on both sides of a near-infrared and ultraviolet absorbing layer (A layer), and a heat-sealing layer (C layer) is provided on the outer side of the transparent layer. Among them, the thickness of the near-infrared and ultraviolet absorbing layer (A layer) is 24 μm, the thickness of the transparent layer (B layer) is 9 μm, and the thickness of the heat-sealing layer (C layer) is 3 μm.

[0052] This embodiment also provides a method for preparing a PET heat-sealing film that blocks infrared rays and ultraviolet rays, comprising the following steps:

[0053] The raw materials for preparing the near-infrared and ultraviolet absorbing layers, the near-infrared absorbing masterbatch, the ultraviolet absorbing masterbatch and the PET polyester chips are added in a mass ratio of 7:7.:86 and fully mixed, added to the main extruder, melt-extruded at 270°C, vacuumed, filtered and then enter the distribution block to form the main extrusion melt;

[0054] The near-infrared absorption masterbatch is a PET-based masterbatch containing a near-infrared absorber, and the preparation method comprises the following steps: mixing PET polyester chips and near-infrared absorber indium tin oxide (ITO) through a twin-screw extruder to granulate to obtain a masterbatch, the extrusion temperature is 275° C., the extruder speed is 350 rpm, and the amount of indium tin oxide is 0.7% of the mass of the masterbatch;

[0055] The ultraviolet absorption masterbatch is a PET-based masterbatch containing an ultraviolet absorber, and the preparation method comprises the following steps: mixing PET polyester chips and benzophenone ultraviolet absorber UV-531 through a twin-screw extruder to granulate to obtain a masterbatch, the extrusion temperature is 275° C., the extruder speed is 350 rpm, and the amount of UV-531 is 0.7% of the mass of the masterbatch;

[0056] The raw material for preparing the transparent layer, the glossy polyester chips, are added into the auxiliary extrusion unit 1, and after being melt-extruded at 270°C, vacuumized, and filtered, the chips enter the distribution block to form the auxiliary extrusion unit 1 melt;

[0057] The raw material PETG masterbatch for preparing the heat sealing layer is added to the auxiliary extrusion 2, and after being melt-extruded at 270°C, vacuumed, and filtered, it enters the distribution block to become the auxiliary extrusion 2 melt;

[0058] The above melt extrusion was used to prepare a CBABC five-layer structure, wherein the rotation speeds of the main extruder, the auxiliary extruder one, and the auxiliary extruder two were 89 rpm, 160 rpm, and 210 rpm, respectively. After extrusion, the film was cast (the casting roller temperature was 15°C), longitudinal stretching (the preheating zone temperature was 60°C, the stretching zone temperature was 110°C, the cooling zone temperature was 25°C, and the stretching ratio was 3.6 times), transverse stretching (the preheating zone temperature was 85°C, the stretching zone temperature was 130°C, the shaping zone temperature was 230°C, the cooling zone temperature was 30°C, and the stretching ratio was 3.6 times), traction and winding (winding speed was 275 m / min), and slitting and packaging were performed in sequence to obtain a PET heat-sealing film that blocks infrared and ultraviolet rays.

[0059] This embodiment also provides an application of a PET heat-sealing film that blocks infrared rays and ultraviolet rays in the preparation of laminated glass.

[0060] Example 3

[0061] This embodiment provides a PET heat-sealing film for blocking infrared and ultraviolet rays, which is a CBABC five-layer film structure, wherein a transparent layer (B layer) is provided on both sides of a near-infrared and ultraviolet absorbing layer (A layer), and a heat-sealing layer (C layer) is provided on the outer side of the transparent layer. Among them, the thickness of the near-infrared and ultraviolet absorbing layer (A layer) is 32 μm, the thickness of the transparent layer (B layer) is 12 μm, and the thickness of the heat-sealing layer (C layer) is 4 μm.

[0062] This embodiment also provides a method for preparing a PET heat-sealing film that blocks infrared rays and ultraviolet rays, comprising the following steps:

[0063] The raw materials for preparing the near-infrared and ultraviolet absorbing layers, the near-infrared absorbing masterbatch, the ultraviolet absorbing masterbatch, and the PET polyester chips are added in a mass ratio of 10:10:80 and fully mixed, added to the main extruder, melt-extruded at 280°C, vacuumed, filtered, and then enter the distribution block to form the main extrusion melt;

[0064] The near infrared absorption masterbatch is a PET-based masterbatch containing a near infrared absorber. The preparation method comprises the following steps: mixing PET polyester chips with cesium tungsten bronze nanoparticles (Cs x WO3) is mixed and extruded by a twin-screw extruder to obtain a masterbatch, the extrusion temperature is 275°C, the extruder speed is 350rpm, and the amount of cesium tungsten bronze nanoparticles is 1.0% of the mass of the masterbatch;

[0065] The ultraviolet absorption masterbatch is a PET-based masterbatch containing an ultraviolet absorber, and the preparation method comprises the following steps: mixing PET polyester chips and benzotriazole ultraviolet absorber UV-326 through a twin-screw extruder to granulate to obtain a masterbatch, the extrusion temperature is 275° C., the extruder speed is 350 rpm, and the amount of UV-326 is 1.0% of the mass of the masterbatch;

[0066] The raw material for preparing the transparent layer, the glossy polyester chips, are added into the auxiliary extrusion unit 1, and after being melt-extruded at 280°C, vacuumized, and filtered, the chips enter the distribution block to form the auxiliary extrusion unit 1 melt;

[0067] The raw material PETG masterbatch for preparing the heat sealing layer is added to the auxiliary extrusion 2, and after being melt-extruded at 280°C, vacuumed, and filtered, it enters the distribution block to become the auxiliary extrusion 2 melt;

[0068] The above melt extrusion was used to prepare a CBABC five-layer structure, wherein the speeds of the main extruder, the auxiliary extruder one, and the auxiliary extruder two were 73 rpm, 146 rpm, and 224 rpm, respectively. After extrusion, the film was successively subjected to cast film (casting roller temperature 19°C), longitudinal stretching (preheating zone temperature 110°C, stretching zone temperature 120°C, cooling zone temperature 40°C, stretching ratio 3.2 times), transverse stretching (preheating zone temperature 100°C, stretching zone temperature 140°C, shaping zone temperature 230°C, cooling zone temperature 50°C, stretching ratio 3.2 times), traction and winding (winding speed of 250 m / min), slitting and packaging to obtain a PET heat-sealing film that blocks infrared and ultraviolet rays.

[0069] This embodiment also provides an application of a PET heat-sealing film that blocks infrared rays and ultraviolet rays in the preparation of laminated glass.

[0070] In other embodiments of the present invention, the thickness of each layer in the PET heat-sealing film can be arbitrarily set within a given range without substantially affecting the overall performance of the film.

[0071] In other embodiments of the present invention, the amount of each raw material and the parameter conditions in the preparation method can be arbitrarily set within a given range, which hardly affects the overall performance of the film.

[0072] Experimental example

[0073] 1. Light transmittance test

[0074] Experimental method: Take the PET heat-sealing film prepared in Examples 1-3, and use a spectrophotometer to test the transmittance of the PET heat-sealing film in the wavelength range of 200-1200nm. The results are shown in Table 1.

[0075] Table 1 Test results of light transmittance of PET heat sealing film prepared in Example

[0076]

[0077] 2. Heat seal strength test

[0078] Experimental method: The PET heat-sealing films prepared in Examples 1-3 were tested for heat-sealing strength according to the QB / T 2358-1998 test method. The results are shown in Table 2.

[0079] Table 2 Heat seal strength test results of PET heat seal film prepared in Example

[0080] project Example 1 Example 2 Example 3 Heat seal strength, N / 15mm 4.2 4.9 5.6

[0081] Conclusion: From the above experimental results, it can be seen that the PET heat-sealing film provided by the present invention can reduce the transmission of invisible light, achieve the effect of reducing the energy exchange inside and outside the film, and make the film have the performance of blocking radiation. In addition, the transparent layer in the film is prepared with optical grade transparent PET as the raw material, which can not only improve the transparency of the film, but also increase the stiffness of the film and improve the winding effect. The heat-sealing layer arranged on the outermost side can give the film self-adhesiveness, so that it can be directly compounded with glass at high temperature, reducing the use of adhesives and release paper, which is more in line with the current green and environmentally friendly development concept.

[0082] The PET heat-sealing film provided by the invention solves the problems of poor radiation protection effect, no protection on the film surface and a self-adhesive surface layer of common PET polyester films, and has good application prospects and high economic value.

[0083] Although the technical scheme and technical effects of the present invention have been described in detail above by means of general description, specific embodiments and experimental examples, for those skilled in the art, any modification, replacement or improvement made without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A PET heat-sealing film for blocking infrared and ultraviolet rays, characterized in that: The PET heat-sealing film is a multi-layer film structure, including a near-infrared and ultraviolet absorbing layer, a transparent layer, and a heat-sealing layer; The raw materials for preparing the near infrared and ultraviolet absorption layers include near infrared absorption masterbatch, ultraviolet absorption masterbatch, and PET polyester chips; The raw materials for preparing the transparent layer include high gloss polyester chips; The raw material for preparing the heat sealing layer includes PETG masterbatch.

2. The PET heat-sealing film according to claim 1, characterized in that: The near-infrared absorption masterbatch is a PET-based masterbatch containing a near-infrared absorber, which is prepared by an extrusion granulation process; the near-infrared absorber includes but is not limited to one or more of cesium tungsten bronze nanoparticles, antimony-doped tin dioxide, indium tin oxide, and lanthanum hexaboride; And / or, the ultraviolet absorption masterbatch is a PET-based masterbatch containing an ultraviolet absorber, which is prepared by an extrusion granulation process; the ultraviolet absorber includes but is not limited to one or more of a benzotriazole ultraviolet absorber and a benzophenone ultraviolet absorber; And / or, the mass ratio of the near-infrared absorption masterbatch, the ultraviolet absorption masterbatch, and the PET polyester chips is 5-10:5-10:80-90.

3. The PET heat-sealing film according to claim 1, characterized in that: The multilayer film structure is a CBABC five-layer film structure, wherein transparent layers (B layers) are arranged on both sides of the near-infrared and ultraviolet absorbing layer (A layer), and a heat sealing layer (C layer) is arranged on the outer side of the transparent layer.

4. The PET heat-sealing film according to claim 1, characterized in that: The thickness of the near infrared and ultraviolet absorbing layer is 8-32 μm, the thickness of the transparent layer is 3-12 μm, and the thickness of the heat sealing layer is 1-4 μm.

5. A method for preparing a PET heat-sealing film for blocking infrared and ultraviolet rays as claimed in any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: The raw materials for preparing the near-infrared and ultraviolet absorbing layer, the transparent layer and the heat-sealing layer are fed separately, and are sequentially subjected to melt extrusion, cast film and biaxial stretching treatment to obtain a PET heat-sealing film that blocks infrared and ultraviolet rays.

6. The preparation method according to claim 5, characterized in that: The melting temperature of the melt for preparing the near infrared and ultraviolet absorbing layer is 260-285°C; And / or, the melting temperature of the melt for preparing the transparent layer is 265-280°C; And / or, the melting temperature of the melt for preparing the heat-sealing layer is 230-285°C.

7. The preparation method according to claim 5, characterized in that: During the tape casting process, the temperature of the casting roller is 15-20°C.

8. The preparation method according to claim 5, characterized in that: The biaxial stretching treatment is to sequentially perform longitudinal stretching and transverse stretching, and the technical parameters of the longitudinal stretching are: preheating zone temperature 60-110°C, stretching zone temperature 110-120°C, cooling zone temperature 25-40°C, and stretching ratio 3-4 times; the technical parameters of the transverse stretching are: preheating zone temperature 85-100°C, stretching zone temperature 100-160°C, shaping zone temperature 160-230°C, cooling zone temperature 30-50°C, and stretching ratio 3-4 times.

9. The preparation method according to claim 5, characterized in that: After the biaxial stretching treatment, the film is traction-reeled and the reeling speed is 150-300 m / min.

10. Use of the infrared and ultraviolet blocking PET heat-sealing film according to any one of claims 1 to 4 in the preparation of laminated glass, optical lenses, and building thermal insulation materials.

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