Functional master batch for PETG shrink film and preparation method of functional master batch

Abstract

The invention discloses a functional master batch for a PETG (polyethylene terephthalate glycol) shrink film, which is prepared from the following raw materials in parts by weight: 100 to 120 parts by weight of terephthalic acid, 30 to 50 parts by weight of 1, 4-cyclohexanedimethanol, 80 to 100 parts by weight of ethylene glycol, 0.1 to 0.2 part by weight of triaryl phosphate, 0.01 to 0.03 part by weight of isocyanate, 0.01 to 0.02 part by weight of potassium tripolyphosphate and 0.1 to 0.2 part by weight of magnesium aluminum silicate. 0.2 to 0.4 part by weight of disodium ethylene diamine tetraacetate, and 0.3 to 0.5 part by weight of other auxiliary agents. The invention also discloses a preparation method of the functional master batch. The shrink film prepared from the functional master batch obtained by the method disclosed by the invention has relatively excellent shrinkage performance, relatively low shrinkage temperature, stable shrinkage force and excellent transverse thermal shrinkage rate.

Description

Technical Field

[0001] The present application relates to a shrink film that can be used for outer packaging materials, and in particular to a functional masterbatch for PETG shrink film and a preparation method thereof. Background Art

[0002] CN 113696572 B discloses a composite PETG heat shrinkable film and its preparation system. The composite PETG heat shrinkable film is composed of an extruded A-layer surface layer, a B-layer core layer and a C-layer bottom layer. The A-layer and the C-layer are respectively arranged on both sides of the B-layer, wherein: the A-layer and the C-layer both include PETG and 5.5wt% to 9.5wt% of the total mass of PETG functional material slices, wherein the PETG functional material slices include 80-95 weight parts of PETG slices, 2-5 weight parts of nano boron nitride, 1-2 weight parts of aluminate, 6-10 weight parts of polydimethylsiloxane and 2-3 weight parts of potassium chloride. The B-layer includes PS and 14.5wt% to 21.5wt% of the total mass of PS functional material slices. The prior art adjusts the functions of the PETG layer and the PS layer by adding a functional masterbatch, so that the die head temperature during co-extrusion after adjustment can be reduced to about 240°C, and the interface corrugation defect can be effectively eliminated and the film layer separation can be avoided. The composite PETG heat shrinkable film of the prior art has the advantages of both PETG and PS. The outer layer is PETG, which is easy to print and has low temperature sensitivity; the inner layer is PS, so the shrinkage force is also reduced, which is convenient for shrinkage.

[0003] The PETG slices used in the PETG functional material of the prior art can be partially or entirely from purchased or pre-prepared raw materials, so the performance of the prepared PETG functional material is limited by the purchased PETG slices or the PETG slices with fixed raw materials. Generally speaking, PETG is generally considered to be a copolymer product obtained by replacing part of the ethylene glycol with 1,4-cyclohexanedimethanol (CHDM) during the synthesis of polyethylene terephthalate (PET), wherein the different addition amounts of CHDM determine the crystallinity of the prepared PETG. However, the crystallinity of PET is very high, and only after the CHDM modification and the crystallinity is reduced can relatively good shrinkage performance be obtained. Therefore, in the case where the shrinkage of the shrinkage film is determined by the non-crystalline region of the material, the shrinkage of PETG obtained by copolymerization of different raw materials is also very different. Therefore, the above-mentioned prior art uses PETG slices composed of specific raw materials, and the shrinkage performance of the functional material prepared by it is relatively difficult to be significantly adjusted by the subsequent addition of other material components. For example, the prior art adds nano boron nitride, aluminate, polydimethylsiloxane and potassium chloride to PETG slices, and its main adjustment target is to reduce the die head temperature during co-extrusion, but relatively speaking, it reduces the shrinkage rate and shrinkage force. Although the reduction is not large, it can still be seen that the adjustment range of the functional masterbatch on the shrinkage performance is limited. Of course, the inventor cannot determine which material component has a greater impact on the shrinkage performance of the shrinkage film. Therefore, under the market demand for flexible production of shrinkage films with different shrinkage performances, it is expected to prepare a functional masterbatch with relatively wider adaptability. Through the cooperation of the functional masterbatch with various additives or film layers, the shrinkage performance can be adjusted relatively more to obtain a shrinkage film suitable for different application scenarios. Summary of the invention

[0004] The technical problem to be solved by the present application is to provide a functional masterbatch for PETG shrink film and a preparation method thereof, so as to reduce or avoid the above-mentioned problems.

[0005] To solve the above technical problems, the present application proposes a functional masterbatch for PETG shrink film, which is prepared from the following raw materials in parts by weight: 100-120 parts by weight of terephthalic acid, 30-50 parts by weight of 1,4-cyclohexanedimethanol, 80-100 parts by weight of ethylene glycol, 0.1-0.2 parts by weight of triaryl phosphate, 0.01-0.03 parts by weight of isocyanate, 0.01-0.02 parts by weight of potassium tripolyphosphate, 0.1-0.2 parts by weight of magnesium aluminum silicate, 0.2-0.4 parts by weight of disodium ethylenediaminetetraacetate, and 0.3-0.5 parts by weight of other additives.

[0006] Preferably, the other auxiliary agent is one or a combination of an anti-adhesive agent, an antioxidant, a stabilizer, a leveling agent, and a flame retardant.

[0007] The present invention also proposes a method for preparing the functional masterbatch, comprising the following steps: adding 100-120 parts by weight of terephthalic acid and 80-100 parts by weight of ethylene glycol to an esterification tank, mixing them uniformly at room temperature, and pre-reacting for 30-60 minutes; then, adding 30-50 parts by weight of 1,4-cyclohexanedimethanol, 0.1-0.2 parts by weight of triaryl phosphate, and 0.01-0.03 parts by weight of isocyanate, which are uniformly mixed, to the esterification tank; setting the reaction conditions of the esterification tank to 230-250° C. and 0.2-0.3Mpa, carrying out the esterification reaction, and after the water output reaches the theoretical value, releasing the system pressure to normal pressure; then, filtering the esterification product from the outlet of the esterification tank and transferring it to the polycondensation tank, while adding the polycondensation tank to the esterification tank. 0.01-0.02 parts by weight of potassium tripolyphosphate are added to the tank, the temperature is maintained at 230-250° C., and the mixture is stirred at normal pressure for 10 minutes; then, vacuum is applied, the temperature in the polycondensation tank 200 is raised to 285° C., the pressure is reduced to below 100 Pa, the reaction is carried out for more than 3 hours, the intrinsic viscosity reaches more than 0.80 dl / g, the temperature is reduced to 230° C., and the mixture is restored to normal pressure; 0.1-0.2 parts by weight of aluminum magnesium silicate, 0.2-0.4 parts by weight of disodium ethylenediaminetetraacetate, and 0.3-0.5 parts by weight of other additives which are uniformly mixed are added to the polycondensation tank; the temperature in the polycondensation tank is maintained at 230° C., the mixture is stirred for 30 minutes, and finally, the polymer melt is filtered, extruded, pelletized, and dried from the outlet of the polycondensation tank to obtain a functional masterbatch of a PETG shrink film.

[0008] The shrinkage film prepared by the functional masterbatch obtained by the method of the present invention has relatively excellent shrinkage performance, a low shrinkage temperature, a stable shrinkage force and an excellent transverse heat shrinkage rate. DETAILED DESCRIPTION

[0009] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific implementation methods of the present application are now described in detail.

[0010] As described in the background art, the present invention hopes to propose a functional masterbatch whose shrinkage performance can be adjusted to a greater extent, so the inventor proposes the following idea, that is, to prepare a functional masterbatch with relatively high shrinkage performance, and when it is needed to be applied to certain scenes with relatively low parameter requirements, the shrinkage parameters can be reduced by adding other ingredients or compounding other materials. For example, generally speaking, the preparation difficulty of shrinkage films with low shrinkage temperature, relatively high shrinkage rate and shrinkage force is relatively high, while the opposite parameter indicators are relatively easy to obtain, which means that by adding some additives or compounding other film layers, it is relatively easy to weaken these parameter indicators, so the adaptability of this functional masterbatch will become wider, that is, it is relatively easy to adjust the shrinkage performance of shrinkage films in various application scenarios.

[0011] In view of this, the present invention proposes a functional masterbatch for PETG shrink film, which is prepared from the following raw materials in parts by weight: 100-120 parts by weight of terephthalic acid, 30-50 parts by weight of 1,4-cyclohexanedimethanol, 80-100 parts by weight of ethylene glycol, 0.1-0.2 parts by weight of triaryl phosphate, 0.01-0.03 parts by weight of isocyanate, 0.01-0.02 parts by weight of potassium tripolyphosphate, 0.1-0.2 parts by weight of magnesium aluminum silicate, 0.2-0.4 parts by weight of disodium ethylenediaminetetraacetate, and 0.3-0.5 parts by weight of other additives.

[0012] Among them, other additives include but are not limited to anti-adhesive agents, antioxidants, stabilizers, leveling agents, flame retardants, etc., or a combination thereof.

[0013] The functional masterbatch of the present application can be prepared by the following method.

[0014] For example, 100-120 parts by weight of terephthalic acid and 80-100 parts by weight of ethylene glycol can be added to the esterification tank, mixed evenly at room temperature, and pre-reacted for 30-60 minutes. After that, 30-50 parts by weight of 1,4-cyclohexanedimethanol, 0.1-0.2 parts by weight of triaryl phosphate, and 0.01-0.03 parts by weight of isocyanate that are evenly mixed are added to the esterification tank. The reaction conditions of the esterification tank are set to 230-250°C and 0.2-0.3Mpa, and the esterification reaction is carried out. After the water output reaches the theoretical value, the system pressure is released to normal pressure.

[0015] Then, the esterification product is filtered and transferred from the outlet of the esterification tank to the polycondensation tank, and 0.01-0.02 parts by weight of potassium tripolyphosphate is added to the polycondensation tank, the temperature is maintained at 230-250° C., and the mixture is stirred at normal pressure for 10 minutes. Then, vacuum is drawn, the temperature in the polycondensation tank 200 is raised to 285° C., the pressure is reduced to below 100 Pa, the reaction is carried out for more than 3 hours, the intrinsic viscosity reaches more than 0.80 dl / g, the temperature is reduced to 230° C., and the mixture is returned to normal pressure.

[0016] 0.1-0.2 parts by weight of aluminum magnesium silicate, 0.2-0.4 parts by weight of disodium ethylenediaminetetraacetate, and 0.3-0.5 parts by weight of other additives that have been uniformly mixed are added into the polycondensation tank.

[0017] The temperature in the polycondensation tank was maintained at 230° C. and stirred for 30 minutes. Finally, the polymer melt was filtered, extruded, pelletized, and dried from the outlet of the polycondensation tank to obtain a PETG shrink film functional masterbatch.

[0018] For example, the conditions of the above preparation method can be used to prepare the functional masterbatch and shrink film of the following examples and comparative examples. The process parameters of the above preparation method are not repeated in the examples and comparative examples, and only the addition amount of various reaction components is described in detail.

[0019] Example 1

[0020] 100 parts by weight of terephthalic acid, 80 parts by weight of ethylene glycol, 30 parts by weight of 1,4-cyclohexanedimethanol, 0.1 parts by weight of triaryl phosphate, and 0.01 parts by weight of isocyanate were added into an esterification tank to carry out an esterification reaction.

[0021] The esterification product is transferred to a polycondensation tank, and 0.01 parts by weight of potassium tripolyphosphate, 0.1 parts by weight of magnesium aluminum silicate, 0.2 parts by weight of disodium ethylenediaminetetraacetate, and 0.3 parts by weight of nano calcium carbonate anti-adhesive are added to the polycondensation tank to carry out a polycondensation reaction.

[0022] In this embodiment, the intrinsic viscosity of the polycondensation reaction product can reach a maximum of 0.80 dl / g.

[0023] Finally, the polymer melt is extruded, pelletized and dried to obtain a PETG shrink film functional masterbatch.

[0024] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 81°C, the transverse heat shrinkage rate is 71% in 2 to 3 seconds, the light transmittance is 95%, and the shrinkage force is 6.1N / m 2 , thickness is 50μm.

[0025] Example 2

[0026] 110 parts by weight of terephthalic acid, 90 parts by weight of ethylene glycol, 40 parts by weight of 1,4-cyclohexanedimethanol, 0.15 parts by weight of triaryl phosphate, and 0.02 parts by weight of isocyanate were added into an esterification tank to carry out an esterification reaction.

[0027] The esterification product was transferred to a polycondensation tank, and 0.015 parts by weight of potassium tripolyphosphate, 0.15 parts by weight of magnesium aluminum silicate, 0.3 parts by weight of disodium ethylenediaminetetraacetate, and 0.4 parts by weight of polytetrahydrofuran leveling agent were added to the polycondensation tank to carry out a polycondensation reaction.

[0028] In this embodiment, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.81 dl / g.

[0029] Finally, the polymer melt is extruded, pelletized and dried to obtain a PETG shrink film functional masterbatch.

[0030] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 80°C, the transverse heat shrinkage rate is 73% in 2 to 3 seconds, the light transmittance is 94%, and the shrinkage force is 6.0N / m 2 , thickness is 50μm.

[0031] Example 3

[0032] 120 parts by weight of terephthalic acid, 100 parts by weight of ethylene glycol, 50 parts by weight of 1,4-cyclohexanedimethanol, 0.2 parts by weight of triaryl phosphate, and 0.03 parts by weight of isocyanate were added into an esterification tank to carry out an esterification reaction.

[0033] The esterification product is transferred to a polycondensation tank, and 0.02 parts by weight of potassium tripolyphosphate, 0.2 parts by weight of magnesium aluminum silicate, 0.4 parts by weight of disodium ethylenediaminetetraacetate, 0.3 parts by weight of nano titanium dioxide stabilizer, and 0.2 parts by weight of decabromodiphenyl ether flame retardant are added to the polycondensation tank to carry out a polycondensation reaction.

[0034] In this embodiment, the intrinsic viscosity of the polycondensation reaction product can reach a maximum of 0.82 dl / g.

[0035] Finally, the polymer melt is extruded, pelletized and dried to obtain a PETG shrink film functional masterbatch.

[0036] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 80°C, the transverse heat shrinkage rate is 72% in 2 to 3 seconds, the light transmittance is 93%, and the shrinkage force is 6.2N / m 2 , thickness is 50μm.

[0037] Based on the limitation of the existing PETG shrink film by the PETG slices with fixed raw materials, the present invention proposes a new preparation process and a combination of specific raw materials based on the raw materials, and improves the shrinkage performance of the prepared PETG by adding different raw material ratios in the esterification and polycondensation stages. The following is a comparison of the performance of the prepared shrink films by different preparation processes and raw material ratios.

[0038] Comparative Example 1

[0039] 100 parts by weight of terephthalic acid, 80 parts by weight of ethylene glycol, and 30 parts by weight of 1,4-cyclohexanedimethanol were added into an esterification tank to carry out an esterification reaction.

[0040] The esterification product is transferred to a polycondensation tank, and 0.3 parts by weight of a nano calcium carbonate anti-adhesive agent is added to the polycondensation tank to carry out a polycondensation reaction. Finally, the polymer melt is extruded, pelletized, and dried to obtain a PETG shrink film functional masterbatch.

[0041] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.69 dl / g.

[0042] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 120°C, the transverse heat shrinkage rate is 67% in 2 to 3 seconds, the light transmittance is 85%, and the shrinkage force is 6.9N / m 2 , thickness is 50μm.

[0043] Comparative Example 2

[0044] 110 parts by weight of terephthalic acid, 90 parts by weight of ethylene glycol, 40 parts by weight of 1,4-cyclohexanedimethanol, 0.15 parts by weight of triaryl phosphate, and 0.02 parts by weight of isocyanate were added into an esterification tank to carry out an esterification reaction.

[0045] The esterification product is transferred to a polycondensation tank, and 0.4 parts by weight of polytetrahydrofuran leveling agent is added to the polycondensation tank to carry out a polycondensation reaction. Finally, the polymer melt is extruded, pelletized, and dried to obtain a PETG shrink film functional masterbatch.

[0046] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.71 dl / g.

[0047] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 115°C, the transverse heat shrinkage rate is 73% in 2 to 3 seconds, the light transmittance is 88%, and the shrinkage force is 6.7N / m 2 , thickness is 50μm.

[0048] Comparative Example 3

[0049] 120 parts by weight of terephthalic acid, 100 parts by weight of ethylene glycol, 50 parts by weight of 1,4-cyclohexanedimethanol, 0.2 parts by weight of triaryl phosphate, and 0.03 parts by weight of isocyanate were added into an esterification tank to carry out an esterification reaction.

[0050] The esterification product is transferred to a polycondensation tank, and 0.3 parts by weight of a nano titanium dioxide stabilizer is added to the polycondensation tank to carry out a polycondensation reaction. Finally, the polymer melt is extruded, pelletized, and dried to obtain a PETG shrink film functional masterbatch.

[0051] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.80 dl / g.

[0052] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 120°C, the transverse heat shrinkage rate is 68% in 2 to 3 seconds, the light transmittance is 89%, and the shrinkage force is 3.8N / m 2 , thickness is 50μm.

[0053] Comparative Example 4

[0054] 100 parts by weight of terephthalic acid, 80 parts by weight of ethylene glycol, 30 parts by weight of 1,4-cyclohexanedimethanol and 0.1 parts by weight of triaryl phosphate were added into an esterification tank to carry out an esterification reaction.

[0055] The esterification product is transferred to a polycondensation tank, and 0.01 parts by weight of potassium tripolyphosphate, 0.1 parts by weight of magnesium aluminum silicate, and 0.3 parts by weight of nano calcium carbonate anti-adhesive agent are added to the polycondensation tank to carry out a polycondensation reaction. Finally, the polymer melt is extruded, pelletized, and dried to obtain a PETG shrink film functional masterbatch.

[0056] In this comparative example, the intrinsic viscosity of the polycondensation reaction product can reach a maximum of 0.75 dl / g.

[0057] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 120°C, the transverse heat shrinkage rate is 75% in 2 to 3 seconds, the light transmittance is 92%, and the shrinkage force is 3.2N / m 2 , thickness is 50μm.

[0058] Comparative Example 5

[0059] 110 parts by weight of terephthalic acid, 90 parts by weight of ethylene glycol, 40 parts by weight of 1,4-cyclohexanedimethanol and 0.02 parts by weight of isocyanate were added into an esterification tank to carry out an esterification reaction.

[0060] The esterification product is transferred to a polycondensation tank, and 0.015 parts by weight of potassium tripolyphosphate, 0.15 parts by weight of magnesium aluminum silicate, 0.3 parts by weight of disodium ethylenediaminetetraacetate, and 0.4 parts by weight of polytetrahydrofuran leveling agent are added to the polycondensation tank to carry out a polycondensation reaction. Finally, the polymer melt is extruded, pelletized, and dried to obtain a PETG shrink film functional masterbatch.

[0061] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.73 dl / g.

[0062] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 108°C, the transverse heat shrinkage rate is 76% in 2 to 3 seconds, the light transmittance is 90%, and the shrinkage force is 4.1N / m 2 , thickness is 50μm.

[0063] Comparative Example 6

[0064] 120 parts by weight of terephthalic acid, 100 parts by weight of ethylene glycol, 50 parts by weight of 1,4-cyclohexanedimethanol, 0.2 parts by weight of triaryl phosphate, and 0.03 parts by weight of isocyanate were added into an esterification tank to carry out an esterification reaction.

[0065] The esterification product is transferred to a polycondensation tank, and 0.02 parts by weight of potassium tripolyphosphate, 0.4 parts by weight of disodium ethylenediaminetetraacetate, 0.3 parts by weight of nano titanium dioxide stabilizer, and 0.2 parts by weight of decabromodiphenyl ether flame retardant are added to the polycondensation tank to carry out a polycondensation reaction. Finally, the polymer melt is extruded, pelletized, and dried to obtain a PETG shrink film functional masterbatch.

[0066] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.80 dl / g.

[0067] The prepared PETG shrink film functional masterbatch is melt-extruded, die-cast, transversely far-infrared stretched, cooled and shaped, rolled up, and slit to form a single-layer shrink film; the maximum shrinkage temperature of the film is 109°C, the transverse heat shrinkage rate is 75% in 2 to 3 seconds, the light transmittance is 84%, and the shrinkage force is 3.9N / m 2 , thickness is 50μm.

[0068] By comparing the above examples with the comparative examples, it can be seen that the shrinkage film prepared by the functional masterbatch obtained by the method of the present invention has relatively excellent shrinkage performance, a low shrinkage temperature, a stable shrinkage force and an excellent transverse heat shrinkage rate.

[0069] Those skilled in the art should understand that although the present application is described in the form of multiple embodiments, not every embodiment contains only one independent technical solution. Such description in the specification is only for the sake of clarity, and those skilled in the art should understand the specification as a whole and regard the technical solutions involved in each embodiment as being able to be combined into different embodiments to understand the scope of protection of the present application.

[0070] The above description is only an illustrative embodiment of the present application and is not intended to limit the scope of the present application. Any equivalent changes, modifications and combinations made by any technician in the field without departing from the concept and principle of the present application shall fall within the scope of protection of the present application.

Claims

1. A functional masterbatch for PETG shrink film, prepared from the following raw materials in parts by weight: 100-120 parts by weight of terephthalic acid, 30-50 parts by weight of 1,4-cyclohexanedimethanol, 80-100 parts by weight of ethylene glycol, 0.1-0.2 parts by weight of triaryl phosphate, 0.01-0.03 parts by weight of isocyanate, 0.01-0.02 parts by weight of potassium tripolyphosphate, 0.1-0.2 parts by weight of magnesium aluminum silicate, 0.2-0.4 parts by weight of disodium ethylenediaminetetraacetate, and 0.3-0.5 parts by weight of other additives.

2. The functional masterbatch according to claim 1, characterized in that The other auxiliary agent is one or a combination of an anti-adhesive agent, an antioxidant, a stabilizer, a leveling agent, and a flame retardant.

3. The method for preparing the functional masterbatch according to claim 1 or 2, comprising the steps of: Add 100-120 parts by weight of terephthalic acid and 80-100 parts by weight of ethylene glycol into an esterification tank, mix them evenly at room temperature, and pre-react for 30-60 minutes; Then, 30-50 parts by weight of 1,4-cyclohexanedimethanol, 0.1-0.2 parts by weight of triaryl phosphate, and 0.01-0.03 parts by weight of isocyanate, which are uniformly mixed, are added to the esterification tank; the reaction conditions of the esterification tank are set to 230-250° C. and 0.2-0.3 MPa, and the esterification reaction is carried out. After the water output reaches the theoretical value, the system pressure is released to normal pressure; Then, the esterification product is filtered and transferred from the outlet of the esterification tank to the polycondensation tank, and 0.01-0.02 parts by weight of potassium tripolyphosphate is added to the polycondensation tank at the same time, the temperature is maintained at 230-250° C., and stirred at normal pressure for 10 minutes; then, vacuum is drawn, the temperature in the polycondensation tank 200 is raised to 285° C., the pressure is reduced to below 100 Pa, the reaction is carried out for more than 3 hours, the intrinsic viscosity reaches more than 0.80 dl / g, the temperature is reduced to 230° C., and the pressure is restored to normal pressure; Add 0.1-0.2 parts by weight of magnesium aluminum silicate, 0.2-0.4 parts by weight of disodium ethylenediaminetetraacetate, and 0.3-0.5 parts by weight of other additives, which are uniformly mixed, into the polycondensation tank; The temperature in the polycondensation tank was maintained at 230° C. and stirred for 30 minutes. Finally, the polymer melt was filtered, extruded, pelletized, and dried from the outlet of the polycondensation tank to obtain a PETG shrink film functional masterbatch.