Preparation system of low-shrinkage-force polyester shrink film for labels

Abstract

A preparation system of a low-shrinkage-force polyester shrink film for labels comprises a PETG polyester chip input pipeline for common films, a first mixing bin and a second mixing bin, the output end of the PETG polyester chip input pipeline for common films is connected with the input end of the first mixing bin, the output end of a functional master batch preparation device is connected with the input end of the second mixing bin, and the output end of the functional master batch preparation device is connected with the input end of the first mixing bin. The input end of the second mixing bin is further connected with a hydroxyethyl cellulose input pipeline and a polysulfone input pipeline; the output end of the first mixing bin is respectively connected with the first double-screw extruder and the third double-screw extruder; the output end of the second mixing bin is connected with a second single-screw extruder; the output end of the first double-screw extruder and the output end of the third double-screw extruder input prepared A-layer thick pieces and C-layer thick pieces into the film drawing mechanism, and the output end of the second single-screw extruder inputs prepared B-layer thick pieces into the film drawing mechanism. By means of the preparation system, the shrink film suitable for being used as a low-shrinkage-force label can be prepared.

Description

Technical Field

[0001] The utility model relates to a preparation system of a low-shrinkage polyester shrink film for labels. Background Art

[0002] Shrink film is often used as packaging and labeling for the outer surface of products such as containers. Conventional shrink film may need to shrink at a temperature of about 140°C. High shrink temperature requires operation at high temperature. In some applications, such as pharmaceutical packaging, high temperature may have an adverse effect on heat-sensitive products. In addition, higher shrink temperature may cause deformation of the packaging bottle.

[0003] CN 110891779 B discloses a multilayer shrink film, which comprises at least one core layer between a first surface layer and a second surface layer, wherein the multilayer shrink film comprises an ethylene / α-olefin interpolymer composition and a low-density polyethylene. However, the heat shrinkage temperature of the shrink film proposed in the prior art has not been significantly reduced, and is still as high as 120° C., and the stability of ethylene-based olefins is relatively poor, and is gradually replaced by modified polyester films.

[0004] CN 112297555 B discloses a heat-shrinkable polyester film, which consists of an A layer, a B layer and a C layer. The A layer and the C layer are respectively arranged on both sides of the B layer. The A layer and the C layer are a polyester surface layer and a polyester bottom layer containing functional material slices, and the B layer is a polyester core layer without functional material slices; the polyester of the A layer and the C layer has the same polyester component as the polyester of the B layer. The shrinkage temperature of the three-layer heat-shrinkable polyester film of the prior art is also as high as 120°C. Although the use of polyester material improves stability, the excessively high shrinkage temperature also limits its application scenarios to temperature, making it difficult to be used in labels for products that require low-temperature packaging.

[0005] In addition, the shrinkage force of the existing shrink film made of polyester film is too large, which can easily cause the thin-walled plastic container to deform when used as a label, and the pattern and text on the label will lose the recognition function due to deformation, affecting the appearance of the product. In addition, the existing technology also lacks a system for preparing similar shrink films. Summary of the invention

[0006] The technical problem to be solved by the utility model is to provide a preparation system of low-shrinkage polyester shrink film for labels, so as to reduce or avoid the above-mentioned problems.

[0007] In order to solve the above technical problems, the utility model proposes a preparation system for low-shrinkage polyester shrink film for labels, which is used for preparing low-shrinkage polyester shrink film for labels composed of extruded A-layer surface layer, B-layer core layer and C-layer bottom layer, characterized in that the preparation system comprises a PETG polyester chip input pipeline for ordinary film, a first mixing bin and a second mixing bin, the output end of the PETG polyester chip input pipeline for ordinary film is connected to the input end of the first mixing bin, the output end of the functional masterbatch preparation device is connected to the input end of the second mixing bin, and the input end of the second mixing bin is further connected to a hydroxyethyl cellulose input pipeline and a polysulfone input pipeline; the output end of the first mixing bin is respectively connected to a first twin-screw extruder and a third twin-screw extruder; the output end of the second mixing bin is connected to a second single-screw extruder; The output ends of the first twin-screw extruder and the third twin-screw extruder input the prepared A-layer thick slice and C-layer thick slice as the surface layer and the bottom layer into the film-drawing mechanism, and the output end of the second single-screw extruder inputs the prepared B-layer thick slice as the core layer into the film-drawing mechanism; wherein the functional masterbatch preparation device includes at least one esterification tank and a condensation tank, the esterification tank has a first inlet for terephthalic acid, a second inlet for ethylene glycol, and a third inlet for connecting to the outlet of the esterification auxiliary material tank; the condensation tank has a fourth inlet for connecting to the outlet of the esterification tank, a fifth inlet for connecting to the outlet of the condensation auxiliary material tank, and a sixth inlet for potassium tripolyphosphate; the outlet of the condensation tank is connected to at least one extruder, the outlet of the extruder is connected to a pelletizer, and the outlet of the pelletizer is connected to a dryer.

[0008] Preferably, the esterification auxiliary material tank is provided with three inlets corresponding to the input of 1,4-cyclohexanedimethanol, triaryl phosphate and isocyanate respectively.

[0009] Preferably, the polycondensation auxiliary material tank is provided with three inlets corresponding to the input of magnesium aluminum silicate, disodium ethylenediaminetetraacetate and other auxiliary agents respectively.

[0010] The structure of the preparation system of the utility model is clear and intuitive, and it is easy to refer to and implement. Other types of shrink films can also be prepared by adjusting the addition amount of each component on the preparation system of the utility model as needed. The low shrinkage polyester shrink film for labels prepared by the preparation system of the utility model is particularly suitable for use as a low shrinkage label, and is conducive to improving product yield during post-processing and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The following drawings are only intended to illustrate and explain the present application, and do not limit the scope of the present application.

[0012] Figure 1 Shown is a schematic cross-sectional structure diagram of a low-shrinkage polyester shrink film for labels according to a specific embodiment of the present application.

[0013] Figure 2 Shown is a schematic structural diagram of a system for preparing a low-shrink polyester shrink film for labels according to a specific embodiment of the present application.

[0014] Figure 3 Shown is a schematic structural diagram of a device for preparing a PETG functional masterbatch of a low-shrink polyester shrink film for labels according to another specific embodiment of the present application. DETAILED DESCRIPTION

[0015] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific implementation of the present application is now described with reference to the accompanying drawings, wherein the same components are numbered the same.

[0016] like Figure 1 As shown, the present application proposes a low-shrinkage polyester shrink film for labels, which adopts a three-layer co-extrusion structure, including a surface layer A, a core layer B and a bottom layer C, wherein the A layer and the C layer are respectively arranged on both sides of the B layer and are both made of PETG for ordinary film, and the B layer is made of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone. Among them, the total weight of the PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of the PETG functional masterbatch slices is 90wt% to 95wt%, the addition amount of hydroxyethyl cellulose is 1wt% to 3wt%, and the rest is polysulfone.

[0017] The thickness of the A layer and the C layer is 1-5 μm, the thickness of the B layer is 18-50 μm, and the total thickness of the three-layer co-extruded structure of the low-shrink polyester shrink film for labels is 20-60 μm. More preferably, the thicknesses of the A layer, the B layer, and the C layer are 2-3 μm, 41-44 μm, and 2-3 μm, respectively, and the total thickness of the low-shrink polyester shrink film for labels is 45-50 μm. The width of the low-shrink polyester shrink film for labels is 500-1000 mm.

[0018] The PETG functional masterbatch in layer B 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.

[0019] Among them, other additives include but are not limited to anti-adhesive agents, antioxidants, stabilizers, leveling agents, flame retardants, etc., or a combination thereof.

[0020] The low shrinkage polyester shrink film for labels of the present application can be Figure 2 The preparation system shown is prepared.

[0021] like Figure 2 As shown, the preparation system of low-shrinkage polyester shrink film for labels of the present application includes a PETG slice input pipeline 500 for ordinary film, a first mixing bin 501 and a second mixing bin 502, the output end of the PETG slice input pipeline 500 for ordinary film is connected to the input end of the first mixing bin 501; the output end of the PETG functional masterbatch preparation device 1000 is connected to the input end of the second mixing bin 502, and the input end of the second mixing bin 502 is further connected to a hydroxyethyl cellulose input pipeline 510 and a polysulfone input pipeline 512.

[0022] Furthermore, the output end of the first mixing bin 501 is respectively connected to the first twin-screw extruder 503 and the third twin-screw extruder 504; the output end of the second mixing bin 502 is connected to the second single-screw extruder 505; the output ends of the first twin-screw extruder 503 and the third twin-screw extruder 504 input the prepared A-layer thick film and C-layer thick film as the surface layer and the bottom layer into the film-drawing mechanism 400, and the output end of the second single-screw extruder 505 inputs the prepared B-layer thick film as the core layer into the film-drawing mechanism 400.

[0023] When the preparation system of the present application is working, the PETG slices for ordinary film are respectively input into the first mixing bin 501 through the PETG slice input pipe 500 for ordinary film, and the prepared PETG functional masterbatch slices are simultaneously input into the second mixing bin 502 through the PETG functional masterbatch preparation device 1000. In addition, hydroxyethyl cellulose and polysulfone are input into the second mixing bin 502 through the hydroxyethyl cellulose input pipe 510 and the polysulfone input pipe 512, and mixed with the PETG functional masterbatch slices.

[0024] The PETG slices for common film in the first mixing bin 501 are respectively prepared into A layer thick slice and C layer thick slice through the first twin-screw extruder 503 and the third twin-screw extruder 504, and the second mixing bin 502 is prepared into B layer thick slice through the second single-screw extruder 505, and the A layer thick slice, B layer thick slice and C layer thick slice are respectively input into the film drawing mechanism 400, and the film drawing mechanism 400 can prepare the film by melt co-extrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, slitting and the like. Figure 1 The three-layer structure label shown uses a low shrink polyester shrink film.

[0025] Furthermore, the preparation system of the present application may also include: Figure 3 The functional masterbatch preparation device 1000 shown in FIG. Figure 3As shown, the functional masterbatch preparation device 1000 of the present application includes at least one esterification tank 100 and a polycondensation tank 200. Those skilled in the art should understand that the functional masterbatch preparation device 1000 of the present application is not limited to only one esterification tank and one polycondensation tank. For example, for different production scales, two or more esterification tanks 100 and two or more polycondensation tanks 200 can be connected in series in sequence, wherein the front esterification tank 100 and polycondensation tank 200 are used for pre-reaction, and the last esterification tank 100 and polycondensation tank 200 are used for final reaction.

[0026] The esterification tank 100 has a first inlet 101 for terephthalic acid, a second inlet 102 for ethylene glycol, and a third inlet 103 for connecting to the outlet of the esterification auxiliary material tank 300 .

[0027] The esterification auxiliary material tank 300 is provided with three inlets for inputting 1,4-cyclohexanedimethanol, triaryl phosphate and isocyanate respectively. Initially, terephthalic acid and ethylene glycol can be added for pre-reaction, and then the three auxiliary materials mixed in the esterification auxiliary material tank 300 are added to the esterification tank 100.

[0028] The polycondensation tank 200 has a fourth inlet 204 for connecting to the outlet of the esterification tank 100 , a fifth inlet 205 for connecting to the outlet of the polycondensation auxiliary material tank 301 , and a sixth inlet 206 for potassium tripolyphosphate.

[0029] The polycondensation auxiliary material tank 301 is provided with three inlets for respectively inputting magnesium aluminum silicate, disodium ethylenediaminetetraacetate and other auxiliary agents. Initially, potassium tripolyphosphate can be added for pre-reaction, and then the three auxiliary materials mixed in the polycondensation auxiliary material tank 301 are added to the polycondensation tank 200.

[0030] Furthermore, the outlet of the polycondensation tank 200 is connected to at least one extruder 600 , the outlet of the extruder 600 is connected to a pelletizer 700 , and the outlet of the pelletizer 800 is connected to a dryer 800 .

[0031] Refer to the following Figure 3 The method for preparing the PETG functional masterbatch of the present application is described in detail.

[0032] 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.

[0033] 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 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.

[0034] 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.

[0035] 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 functional masterbatch.

[0036] The low-shrinkage polyester shrink film for labels of the present application can be prepared by the following steps.

[0037] For example, the prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of the PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of the PETG functional masterbatch slices is 90wt% to 95wt%, the addition amount of hydroxyethyl cellulose is 1wt% to 3wt%, and the rest is polysulfone. The PETG slices for ordinary film are used as the surface layer and bottom layer raw materials respectively, and a three-layer structure of low shrinkage polyester shrink film for labels is made through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting.

[0038] The structure of the preparation system of the present application is clear and intuitive, and it is easy to refer to and implement. Other types of shrink films can also be prepared by adjusting the addition amount of each component on the preparation system of the present application as needed. The low shrinkage polyester shrink film for labels prepared by the preparation system of the present application is particularly suitable for use as a low shrinkage label, and is conducive to improving product yield during post-processing and use.

[0039] Example 1

[0040] 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.

[0041] 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.

[0042] In this embodiment, the intrinsic viscosity of the polycondensation reaction product can reach a maximum of 0.80 dl / g.

[0043] Finally, the polymer melt is extruded, pelletized and dried to obtain the PETG functional masterbatch.

[0044] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 90wt%, the addition amount of hydroxyethyl cellulose is 1wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0045] The thickness of the A layer of the prepared shrink film is 2 μm, the thickness of the B layer is 41 μm, the thickness of the C layer is 2 μm, the total thickness is 45 μm, and the width is 500 mm.

[0046] The maximum shrinkage temperature of the shrink film is 83°C, the transverse heat shrinkage rate is 70% in 2 to 3 seconds, the light transmittance is 96%, and the shrinkage force is 4.0N / m 2 .

[0047] Comparative Example 1

[0048] The PETG functional masterbatch prepared in Example 1 was 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 was 81°C, the transverse heat shrinkage rate was 71% in 2 to 3 seconds, the light transmittance was 95%, and the shrinkage force was 6.1 N / m 2 , thickness is 50μm.

[0049] The PETG functional masterbatch slices prepared in Example 1 were added in an amount of 90wt% of the total weight of the core layer, and were uniformly mixed with the PETG polyester slices for ordinary film to serve as the core layer raw material; the PETG slices for ordinary film were used as the surface layer and bottom layer raw materials, respectively, and a PETG shrink film with an ABC three-layer structure was prepared by melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting.

[0050] The thickness of the A layer of the prepared PETG shrink film is 2 μm, the thickness of the B layer is 41 μm, the thickness of the C layer is 2 μm, the total thickness is 45 μm, and the width is 500 mm.

[0051] The maximum shrinkage temperature of the prepared PETG shrink film is 83°C, the lateral heat shrinkage rate is 70% in 2 to 3 seconds, the light transmittance is 96%, and the shrinkage force is 6.0N / m 2 .

[0052] Example 2

[0053] 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.

[0054] 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.

[0055] In this embodiment, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.81 dl / g.

[0056] Finally, the polymer melt is extruded, pelletized and dried to obtain the PETG functional masterbatch.

[0057] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 93wt%, the addition amount of hydroxyethyl cellulose is 2wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0058] The thickness of the A layer of the prepared shrink film is 3 μm, the thickness of the B layer is 44 μm, the thickness of the C layer is 3 μm, the total thickness is 50 μm, and the width is 800 mm.

[0059] The maximum shrinkage temperature of the shrink film is 82°C, the transverse heat shrinkage rate is 72% in 2 to 3 seconds, the light transmittance is 95%, and the shrinkage force is 3.9N / m 2 .

[0060] Comparative Example 2

[0061] The PETG functional masterbatch prepared in Example 2 was 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 was 80°C, the transverse heat shrinkage rate was 73% in 2 to 3 seconds, the light transmittance was 94%, and the shrinkage force was 5.8 N / m 2 , thickness is 50μm.

[0062] The PETG functional masterbatch slices prepared in Example 2 were added in an amount of 93wt% of the total weight of the core layer, and were uniformly mixed with the PETG polyester slices for ordinary film to serve as the core layer raw material; the PETG slices for ordinary film were used as the surface layer and bottom layer raw materials, respectively, and a PETG shrink film with an ABC three-layer structure was prepared by melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting.

[0063] The thickness of the A layer of the prepared PETG shrink film is 3 μm, the thickness of the B layer is 44 μm, the thickness of the C layer is 3 μm, the total thickness is 50 μm, and the width is 800 mm.

[0064] The maximum shrinkage temperature of the prepared PETG shrink film is 82°C, the lateral heat shrinkage rate is 72% in 2 to 3 seconds, the light transmittance is 95%, and the shrinkage force is 5.9N / m 2 .

[0065] Example 3

[0066] 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.

[0067] 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.

[0068] In this embodiment, the intrinsic viscosity of the polycondensation reaction product can reach a maximum of 0.82 dl / g.

[0069] Finally, the polymer melt is extruded, pelletized and dried to obtain the PETG functional masterbatch.

[0070] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 95wt%, the addition amount of hydroxyethyl cellulose is 3wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0071] The thickness of the A layer of the prepared shrink film is 5 μm, the thickness of the B layer is 50 μm, the thickness of the C layer is 5 μm, the total thickness is 60 μm, and the width is 1000 mm.

[0072] The maximum shrinkage temperature of the shrink film is 80°C, the transverse heat shrinkage rate is 71% in 2 to 3 seconds, the light transmittance is 94%, and the shrinkage force is 3.8N / m 2 .

[0073] Comparative Example 3

[0074] The PETG functional masterbatch prepared in Example 3 was 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 was 80°C, the transverse heat shrinkage rate was 72% in 2 to 3 seconds, the light transmittance was 93%, and the shrinkage force was 6.2 N / m 2 , thickness is 50μm.

[0075] The PETG functional masterbatch slices prepared in Example 3 were added in an amount of 95wt% of the total weight of the core layer, and were uniformly mixed with the PETG polyester slices for ordinary film to serve as the core layer raw material; the PETG slices for ordinary film were used as the surface layer and bottom layer raw materials, respectively, and a PETG shrink film with an ABC three-layer structure was prepared by melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting.

[0076] The thickness of the A layer of the prepared PETG shrink film is 5 μm, the thickness of the B layer is 50 μm, the thickness of the C layer is 5 μm, the total thickness is 60 μm, and the width is 3000 mm.

[0077] The maximum shrinkage temperature of the prepared PETG shrink film is 80°C, the lateral heat shrinkage rate in 2 to 3 seconds is 71%, the light transmittance is 94%, and the shrinkage force is 6.1N / m 2 .

[0078] By comparing the above embodiments, it can be seen that the single-layer or three-layer PETG shrink film prepared from the PETG functional masterbatch of the present application has a lower shrinkage temperature, and the shrinkage rate and shrinkage force are relatively high, and has excellent shrinkage performance. In addition, by adding a small amount of hydroxyethyl cellulose and polysulfone to the PETG functional masterbatch of the core layer, the shrinkage force can be significantly reduced, while maintaining a higher shrinkage rate and a lower shrinkage temperature. This improved shrink film is particularly suitable for use as a low-shrinkage-force label, which is conducive to improving product yield during post-processing and use.

[0079] The following further compares the performance of shrinkage films prepared by different preparation processes and raw material ratios through other comparative examples.

[0080] Comparative Example 4

[0081] 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.

[0082] 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 functional masterbatch.

[0083] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.69 dl / g.

[0084] The prepared PETG 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.

[0085] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 90wt%, the addition amount of hydroxyethyl cellulose is 1wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0086] The thickness of the A layer of the prepared shrink film is 2 μm, the thickness of the B layer is 41 μm, the thickness of the C layer is 2 μm, the total thickness is 45 μm, and the width is 500 mm.

[0087] The maximum shrinkage temperature of the shrink film is 125℃, the transverse heat shrinkage rate is 65% in 2-3 seconds, the light transmittance is 86%, and the shrinkage force is 4.5N / m 2 .

[0088] Comparative Example 5

[0089] 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.

[0090] 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 functional masterbatch.

[0091] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.71 dl / g.

[0092] The prepared PETG 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.

[0093] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 93wt%, the addition amount of hydroxyethyl cellulose is 2wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0094] The thickness of the A layer of the prepared shrink film is 3 μm, the thickness of the B layer is 44 μm, the thickness of the C layer is 3 μm, the total thickness is 50 μm, and the width is 800 mm.

[0095] The maximum shrinkage temperature of the prepared PETG shrink film is 117°C, the transverse heat shrinkage rate is 70% in 2 to 3 seconds, the light transmittance is 86%, and the shrinkage force is 4.4N / m 2 .

[0096] Comparative Example 6

[0097] 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.

[0098] 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 functional masterbatch.

[0099] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.80 dl / g.

[0100] The prepared PETG 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 6.8N / m 2 , thickness is 50μm.

[0101] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 95wt%, the addition amount of hydroxyethyl cellulose is 3wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0102] The thickness of the A layer of the prepared shrink film is 5 μm, the thickness of the B layer is 50 μm, the thickness of the C layer is 5 μm, the total thickness is 60 μm, and the width is 100 mm.

[0103] The maximum shrinkage temperature of the prepared PETG shrink film is 124°C, the transverse heat shrinkage rate is 66% in 2 to 3 seconds, the light transmittance is 88%, and the shrinkage force is 4.6N / m 2 .

[0104] Comparative Example 7

[0105] 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.

[0106] 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 functional masterbatch.

[0107] In this comparative example, the intrinsic viscosity of the polycondensation reaction product can reach a maximum of 0.75 dl / g.

[0108] The prepared PETG 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 6.5N / m 2 , thickness is 50μm.

[0109] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 90wt%, the addition amount of hydroxyethyl cellulose is 1wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0110] The thickness of the A layer of the prepared shrink film is 2 μm, the thickness of the B layer is 41 μm, the thickness of the C layer is 2 μm, the total thickness is 45 μm, and the width is 500 mm.

[0111] The maximum shrinkage temperature of the prepared PETG shrink film is 123°C, the lateral heat shrinkage rate is 73% in 2 to 3 seconds, the light transmittance is 93%, and the shrinkage force is 4.3N / m 2 .

[0112] Comparative Example 8

[0113] 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.

[0114] 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 functional masterbatch.

[0115] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.73 dl / g.

[0116] The prepared PETG 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 6.5N / m 2 , thickness is 50μm.

[0117] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 93wt%, the addition amount of hydroxyethyl cellulose is 2wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0118] The thickness of the A layer of the prepared shrink film is 3 μm, the thickness of the B layer is 44 μm, the thickness of the C layer is 3 μm, the total thickness is 50 μm, and the width is 800 mm.

[0119] The maximum shrinkage temperature of the prepared PETG shrink film is 110°C, the lateral heat shrinkage rate is 77% in 2 to 3 seconds, the light transmittance is 91%, and the shrinkage force is 4.7N / m 2 .

[0120] Comparative Example 9

[0121] 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.

[0122] 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 functional masterbatch.

[0123] In this comparative example, the maximum intrinsic viscosity of the polycondensation reaction product can reach 0.80 dl / g.

[0124] The prepared PETG 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 7.9N / m 2 , thickness is 50μm.

[0125] The prepared PETG functional masterbatch slices are uniformly mixed with hydroxyethyl cellulose and polysulfone as the core layer raw material. Among them, the total weight of PETG functional masterbatch slices, hydroxyethyl cellulose and polysulfone is 100wt%, the addition amount of PETG functional masterbatch slices is 95wt%, the addition amount of hydroxyethyl cellulose is 3wt%, and the rest is polysulfone. Ordinary film PETG slices are used as surface layer and bottom layer raw materials respectively, and through melt coextrusion, die casting, transverse far-infrared stretching, cooling and shaping, winding, and slitting, a low-shrinkage polyester shrink film for labels with an ABC three-layer structure is made.

[0126] The thickness of the A layer of the prepared shrink film is 5 μm, the thickness of the B layer is 50 μm, the thickness of the C layer is 5 μm, the total thickness is 60 μm, and the width is 100 mm.

[0127] The maximum shrinkage temperature of the prepared PETG shrink film is 108°C, the lateral heat shrinkage rate is 77% in 2 to 3 seconds, the light transmittance is 86%, and the shrinkage force is 4.3N / m 2 .

[0128] By comparing the above comparative examples, it can be seen that the functional masterbatch used as the comparison fails to effectively reduce the shrinkage temperature, and the value of the transverse heat shrinkage rate is not stable. The comparison functional masterbatch mixed with hydroxyethyl cellulose and polysulfone has a poorer shrinkage force reduction effect than the examples of the present application.

[0129] 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.

[0130] 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 system for preparing a low-shrinkage polyester shrink film for labels, which is used to prepare a low-shrinkage polyester shrink film for labels composed of an extruded A surface layer, a B core layer and a C bottom layer, characterized in that: The preparation system comprises a PETG polyester slice input pipeline for common film, a first mixing bin and a second mixing bin, the output end of the PETG polyester slice input pipeline for common film is connected to the input end of the first mixing bin, the output end of the functional masterbatch preparation device is connected to the input end of the second mixing bin, and the input end of the second mixing bin is further connected to a hydroxyethyl cellulose input pipeline and a polysulfone input pipeline; the output end of the first mixing bin is respectively connected to a first twin-screw extruder and a third twin-screw extruder; the output end of the second mixing bin is connected to a second single-screw extruder; the output ends of the first twin-screw extruder and the third twin-screw extruder use the prepared A layer thick slice and C layer thick slice as the surface layer and the bottom layer The output end of the second single-screw extruder inputs the prepared B layer thick sheet as the core layer into the film-drawing mechanism; wherein the functional masterbatch preparation device includes at least one esterification tank and a polycondensation tank, the esterification tank has a first inlet for terephthalic acid, a second inlet for ethylene glycol and a third inlet for connecting the outlet of the esterification auxiliary material tank; the polycondensation tank has a fourth inlet for connecting the outlet of the esterification tank, a fifth inlet for connecting the outlet of the polycondensation auxiliary material tank and a sixth inlet for potassium tripolyphosphate; the outlet of the polycondensation tank is connected to at least one extruder, the outlet of the extruder is connected to a pelletizer, and the outlet of the pelletizer is connected to a dryer.

2. The preparation system according to claim 1, characterized in that: The esterification auxiliary material tank is provided with three inlets for respectively inputting 1,4-cyclohexanedimethanol, triaryl phosphate and isocyanate.

3. The preparation system according to claim 1, characterized in that: The polycondensation auxiliary material tank is provided with three inlets corresponding to the input of magnesium aluminum silicate, disodium ethylenediaminetetraacetate and other auxiliary agents respectively.

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