A bio-based copolyester shrink film for medical device packaging and methods of making and using the same

Abstract

The present application belongs to the technical field of high polymer materials, and particularly relates to a bio-based copolyester shrink film for medical device packaging, a preparation method and application thereof. The bio-based copolyester shrink film for medical device packaging prepared by the present application has a five-layer structure composed of an inner and outer surface layer of furan dimethyl acid copolyester modified by nano-silicon dioxide, a mixed resin core layer of PEFG and PBAT, and an intermediate adhesive layer of mixed resin between the surface layer and the core layer. The film has more than 50% bio-based raw materials, the same high shrinkage effect as the petroleum-based PETG shrink film, good puncture resistance, and can achieve good results in the medical device packaging process. Compared with the prior art, the unique ABCBA five-layer structure of the film uses the B layer as the recycling layer for recycling and granulation of the prepared film, which is beneficial to the subsequent recycling system, effectively improves the production efficiency of the film, saves the high polymer resin, ensures the stability of the quality, greatly reduces the cost, and has good economic benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and particularly relates to a bio-based copolyester film for medical device packaging as well as a preparation method and application thereof. BACKGROUND

[0002] The information disclosed in this Background section is for the purpose of increasing the understanding of the background of the application without admitting that any of the information constitutes prior art.

[0003] In the field of shrink packaging, PVC, PETG and OPS shrink films are the three main shrink materials on the market. The manufacturing of raw materials for PVC shrink film is a high energy consumption project, mainly from coal chemical industry. On the other hand, PVC materials will produce international first-class carcinogen-dioxin during heating or incineration process. Once produced, it will not disappear, and there is great difficulty in recycling and reuse of PVC materials and no mature solution. Therefore, with the national "double reduction" policy, PVC shrink film is gradually reduced; the application field of OPS shrink film is relatively narrow due to its differentiated ink system and natural temperature shrinkage; PETG shrink film material only contains C, H and O three substances, which is environmentally friendly, has good chemical resistance, high shrinkage rate (up to 80%), and good recycling. At present, it is the best way to replace PVC shrink film.

[0004] At present, the PETG shrink film on the market usually adopts the technical route of copolymerization of terephthalic acid (PTA), ethylene glycol (EG), 1,4-cyclohexane dimethyl alcohol (CHDM) or neopentyl glycol (NPG) and other materials to obtain PETG chips, and then stretching to form PETG film. In the shrink packaging of medical devices, the main problems encountered are: (1) the shape of medical devices is more, and the stiffness of ordinary PETG shrink film is too large during shrinkage, which is easy to break; (2) the raw materials of ordinary PETG shrink film are all from petroleum. Under the global drive of carbon reduction, brand owners need bio-based copolyester shrink film with less carbon footprint.

[0005] Therefore, it is urgent for those skilled in the art to find a bio-based copolyester film that can be applied in the shrink packaging of medical devices, which can ensure that the film has both the shrinkage characteristics of petroleum-based PETG shrink film and high toughness, and can also meet the requirement of carbon reduction, which will have very important environmental protection significance and application value. SUMMARY

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a bio-based copolyester shrink film for medical device packaging, its preparation method, and its applications. The bio-based copolyester shrink film prepared by this invention exhibits the same high shrinkage rate as petroleum-based PETG shrink film, along with excellent puncture resistance and sealing properties. This enables optimal performance in the medical device packaging process and helps reduce overall carbon emissions and product dependence on petroleum, demonstrating significant environmental and social value.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] In a first aspect, the present invention provides a bio-based copolyester shrink film for medical device packaging, the film having a five-layer structure of ABCBA, wherein layer A is the inner and outer outer layers, layer C is the core layer, and layer B is the intermediate adhesive layer between layer A and layer C;

[0009] Among them, layer A is a copolyester resin of furan dicarboxylic acid modified with nano-silica, layer C is a mixed resin of copolyester of furan dicarboxylic acid PEFG and polybutylene adipate / terephthalate PBAT, and layer B is a mixture of layer A and layer C.

[0010] Preferably, the thickness of the bio-based copolyester shrink film is 20-100 μm, and the thickness ratio of the five ABCBA layers is 5-10:5-10:60-80:5-10:5-10.

[0011] Preferably, the mass of nano-silica in layer A is 0.1-0.5% of the total resin mass, and the particle size of nano-silica is 10-100 nm; the mass ratio of PEFG resin to PBAT resin in layer C is 60-90:10-40; and the mass ratio of layer A to layer C in layer B is 10-20:60-80.

[0012] Preferably, the density of the nano-silica-modified furanyl dicarboxylic acid copolyester resin is 1.36-1.40 g / cm³. 3 The PEFG resin has a melting point of 202-208℃, an intrinsic viscosity of 0.80-0.85 dl / g, and a terminal carboxyl group content of 10-15 mmol / kg; the density of the PEFG resin is 1.36-1.40 g / cm³. 3 The PBAT resin has a melting point of 200-210℃, an intrinsic viscosity of 0.80-0.85 dl / g, and a terminal carboxyl group content of 10-20 mmol / kg; the PBAT resin has a melting point of 120-130℃ and a density of 1.20-1.25 g / cm³. 3 The terminal carboxyl group content is 8-15 mmol / kg, and the melt index is 4.0-4.5 g / 10 min (190℃ / 2.16 g).

[0013] In a second aspect, the present application provides a preparation method of the above-mentioned bio-based copolyester shrink film for medical device packaging, comprising the following steps:

[0014] S1, copolymerizing bio-based furan dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano-silicon dioxide to obtain bio-based furan dicarboxylic acid copolyester resin sheet modified by nano-silicon dioxide, and then an outer layer A is prepared;

[0015] S2, copolymerizing bio-based furan dicarboxylic acid, bio-based ethylene glycol and neopentyl glycol to obtain bio-based furan dicarboxylic acid copolyester sheet, and then mixing with polybutylene adipate / terephthalate to prepare a core layer C;

[0016] S3, mixing the outer layer A and the core layer C to prepare an intermediate adhesive B layer;

[0017] S4, ABCBA five-layer matching of the outer layer A, the intermediate adhesive B layer and the core layer C, and then preparing a bio-based copolyester shrink film.

[0018] Preferably, in step S1, the copolymerization is a copolymerization reaction of bio-based furan dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano-silicon dioxide in the presence of a composite catalyst;

[0019] Specifically, bio-based furan dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano-silicon dioxide are first mixed, and then a composite catalyst is added for esterification reaction to obtain an esterification liquid with stable performance; then the esterification liquid is subjected to pre-polycondensation reaction to obtain a pre-polycondensate; finally, the pre-polycondensate is subjected to negative pressure polymerization reaction to obtain bio-based furan dicarboxylic acid copolyester modified by nano-silicon dioxide;

[0020] Wherein, the mass ratio of bio-based furan dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano-silicon dioxide is 60-80%:20-40%:5-15%:0.2-1.5%; the composite catalyst is a mixture of ethylene glycol antimony and tetrabutyl titanate, and the mass ratio of ethylene glycol antimony to tetrabutyl titanate is 60-80:20-40; the mass of the composite catalyst is 200-400 ppm;

[0021] The reaction temperature of the esterification reaction is 200-245℃, and the reaction time is 30-90min;

[0022] The specific operation of the pre-polycondensation reaction is: using a melt pump to uniformly hit the pre-polycondensation reactor after passing through a 20-60 μm candle core filter, using an anchor stirrer to stir at a speed of 50-200 r / min for 30-60 minutes, then continuously increasing the temperature to 240-260°C, and then reacting under a vacuum of 500 Pa for 15 min to obtain a pre-polycondensation product with a certain degree of polymerization;

[0023] The specific operation of the negative pressure polymerization reaction is: pressing the pre-polycondensation product into a polycondensation reactor after passing through a 20-40 μm candle core filter, then continuously increasing the temperature to 270-290°C, and then performing negative pressure polymerization reaction under a vacuum degree of 10-50 Pa, controlling the reaction time to be 3-6 hours, and then cutting and drying underwater to obtain the product.

[0024] Preferably, in step S1, the outer layer A is obtained by melting and plasticizing the nanosilica modified bio-based furandicarboxylic acid copolyester chip through a twin-screw extruder; the extrusion temperature of the nanosilica modified furandicarboxylic acid copolyester chip is 190-230°C.

[0025] Preferably, in step S2, the copolymerization modification is a copolymerization reaction of bio-based furandicarboxylic acid, bio-based ethylene glycol and neopentyl glycol in the presence of a composite catalyst.

[0026] Specifically, bio-based furandicarboxylic acid, bio-based ethylene glycol and neopentyl glycol are first mixed, then a composite catalyst is added to perform esterification reaction to obtain an esterification liquid with stable performance; then the esterification liquid is subjected to pre-polycondensation reaction to obtain a pre-polycondensation product; and finally the pre-polycondensation product is subjected to negative pressure polymerization reaction to obtain a bio-based furandicarboxylic acid copolyester.

[0027] The mass ratio of the bio-based furandicarboxylic acid, bio-based ethylene glycol and neopentyl glycol is 60-80%:20-40%:5-15%; the composite catalyst is a mixture of ethylene glycol antimony and tetrabutyl titanate, and the mass ratio of the ethylene glycol antimony and tetrabutyl titanate is 60-80:20-40; and the mass of the composite catalyst is 200-400 ppm.

[0028] The reaction temperature of the esterification reaction is 200-245°C, and the reaction time is 30-90 min.

[0029] The specific operation of the pre-polycondensation reaction is: using a melt pump to uniformly hit the pre-polycondensation reactor after passing through a 20-60 μm candle core filter, using an anchor stirrer to stir at a speed of 50-200 r / min for 30-60 minutes, then continuously increasing the temperature to 240-260°C, and then reacting under a vacuum of 500 Pa for 15 min to obtain a pre-polycondensation product with a certain degree of polymerization.

[0030] The specific operation of the negative pressure polymerization reaction is: the precondensation polymer is pressed into a condensation reaction kettle through a 20-40 μm candle core filter, then the temperature is continuously increased to 270-290 ℃, and the negative pressure polymerization reaction is carried out under a vacuum degree of 10-50 Pa, the reaction time is controlled to be 3-6 hours, and then underwater pelletization and drying are carried out to obtain the product.

[0031] Preferably, in step S2, the core layer C is obtained by melting and plasticizing the bio-based furan dicarboxylic acid copolyester chip and the polybutylene adipate / terephthalate after mixing them into a double screw extruder; the extrusion temperature of the mixed resin of the bio-based furan dicarboxylic acid copolyester chip and the polybutylene adipate / terephthalate is 180-230 ℃.

[0032] Preferably, in step S3, the intermediate adhesive layer B is obtained by melting and plasticizing the mixture of the A layer material and the C layer material into a double screw extruder; the extrusion temperature of the mixture of the intermediate adhesive layer B is 180-230 ℃.

[0033] Preferably, the length-diameter ratio of the double screw extruder is 38-42:1, and the vacuum degree is 10-80 Pa.

[0034] Preferably, in step S4, the outer surface layer A, the intermediate adhesive layer B and the core layer C need to be filtered through a filter respectively, then enter the ABCBA five-layer adapter, and finally flow out from the ABCBA five-layer die, form a cast sheet on the quenching roller, then the cast sheet is preheated by a roller, stretched in the longitudinal direction at a certain ratio, preheated by hot air in an oven, stretched in the transverse direction at a certain ratio, and finally heat set at a certain temperature and cooled to obtain the bio-based copolyester shrink film;

[0035] Preferably, the filter is a five-layer screen filter, and the filter precision is 600-800 mesh;

[0036] The temperature of the quenching roller is 30-40 ℃;

[0037] The cast sheet is formed by electrostatic adsorption silk under electrostatic adsorption conditions, wherein the voltage is set to 9-12 kV, and the current is set to 5-10 mA;

[0038] The temperature of the roller preheating is 60-80 ℃;

[0039] The ratio of the longitudinal stretching is 1.01-2.0 times, and the temperature of the longitudinal stretching is 50-80 ℃;

[0040] The hot air preheating temperature of the oven during the transverse stretching is 120-70 ℃; preferably, the preheating is performed in the form of gradually decreasing temperature;

[0041] The transverse stretching ratio is 4.5-6.0 times, and the temperature of the transverse stretching is 60-100 DEG C.

[0042] The temperature of the heat setting treatment is 60-100 DEG C.

[0043] The temperature of the cooling treatment is 30-40 DEG C.

[0044] Preferably, in step S4, the edge and corner scraps after the edge trimming and slitting of the bio-based copolyester shrink film are crushed and then fed into the B layer for reuse, and the proportion of the edge and corner scraps in the B layer accounts for 50%-100% of the total mass of the B layer.

[0045] In a third aspect, the application provides an application of the A layer of the bio-based copolyester shrink film for medical device packaging in printing multi-color ink and solvent adhesion.

[0046] Preferably, in the process of making a sleeve, the A layer of the bio-based copolyester shrink film for medical device packaging needs to be self-adhered by using a solvent; further preferably, the solvent is selected from one or more of 1,4-dioxane, 1,3-dioxolane, chloroform, and tetrahydrofuran.

[0047] In a fourth aspect, the application provides an application of the bio-based copolyester shrink film for medical device packaging in medical device packaging materials.

[0048] The beneficial effects achieved by one or more technical solutions of the application are as follows:

[0049] (1) The bio-based copolyester shrink film for medical device packaging of the application adopts a special bio-based material, structure and process, has a special five-layer structure, and the inner and outer surface layers adopt a nano-silica modified bio-based furandicarboxylic acid copolymer resin obtained by copolymerization modification of bio-based furandicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano-silica, which has the printability of multi-color ink and high adhesion under solvent, and can be conveniently made into a sleeve for sleeve labeling; the core layer C layer adopts a mixed resin of PEFG obtained by copolymerization modification of bio-based furandicarboxylic acid, bio-based ethylene glycol and neopentyl glycol and biodegradable PBAT; the bio-based copolyester shrink film prepared by the application has good shrinkage characteristics and bio-based properties as a whole, and the addition of PBAT increases the toughness of the bio-based copolyester shrink film, greatly improving the puncture resistance.

[0050] (2) The application finds a bio-based copolyester shrink film convenient to recycle, which has an ABCBA five-layer structure, the B layer is a mixed layer of A layer and C layer resin, has good adhesion with A layer and C layer, and can be used as a recycling layer for recycling and granulation of the bio-based copolyester shrink film, improves the production efficiency of the film, saves high molecular resin, and ensures the stability of quality.

[0051] (3) The preparation method of the application has universality and is easy to scale up. BRIEF DESCRIPTION OF DRAWINGS

[0052] The drawings accompanying the specification of the application form a part of the application and serve to further illustrate the application, the illustrative embodiments of the application and their description serve to explain the application without constituting an improper limitation thereof.

[0053] Figure 1 Structure schematic view of the bio-based copolyester shrink film for medical device packaging prepared for Example 1 of the application. DETAILED DESCRIPTION

[0054] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application belongs.

[0055] In order to enable those skilled in the art to more clearly understand the technical solutions of the application, the technical solutions of the application will be described in detail below with specific examples.

[0056] Example 1: The present example provides a bio-based copolyester shrink film for medical device packaging and a preparation method thereof, comprising the following steps:

[0057] The furan dimethyl acid copolyester with a density of 1.36 g / cm 3 , a melting point of 205℃, a characteristic viscosity of 0.80 dl / g, and a terminal carboxyl group content of 10 mmol / kg is used as the A layer material, is added to a double screw extruder with a length-diameter ratio of 38:1, is melted at a temperature of 220℃, and the obtained melt is used as the inner and outer surface layer A layer of the bio-based copolyester shrink film; the mass of the nano-silicon dioxide is 0.5% of the mass of the A layer resin, the particle size of the nano-silicon dioxide is 200 nm, and the thickness of the A layer accounts for 10% of the total film thickness.

[0058] The furan dimethyl acid copolyester with a density of 1.36 g / cm 3 , a melting point of 205℃, a characteristic viscosity of 0.80 dl / g, and a terminal carboxyl group content of 10 mmol / kg is used as the A layer material, is added to a double screw extruder with a length-diameter ratio of 38:1, is melted at a temperature of 220℃, and the obtained melt is used as the inner and outer surface layer A layer of the bio-based copolyester shrink film; the mass of the nano-silicon dioxide is 0.5% of the mass of the A layer resin, the particle size of the nano-silicon dioxide is 200 nm, and the thickness of the A layer accounts for 10% of the total film thickness. 3A mixture of PBAT with a terminal carboxyl group content of 10 mmol / kg and a melt index of 4.0 g / 10 min (190℃ / 2.16 g) at a mass ratio of 90:10 was used as the C-layer material. This mixture was added to a twin-screw extruder with an aspect ratio of 38:1 and melted at 220℃. The resulting melt was used as the core layer C of the bio-based copolyester shrink film. The C-layer thickness accounted for 80% of the total film thickness.

[0059] The A layer material and the C layer material are mixed in the ratio of the actual A layer thickness and the C layer thickness, and then added to a twin-screw extruder to melt and form the B layer; the thickness of the B layer accounts for 10% of the total film thickness;

[0060] The above-mentioned ABC three-layer melt is filtered through an 800-mesh filter in a mass percentage ratio of 10 / 10 / 80, and then enters the ABCBA five-layer adapter before flowing out of the ABCBA five-layer coat hanger-type die head; wherein the ratio of the five layers of ABCBA is 5:5:80:5:5.

[0061] The five fluid layers described above are formed into a cast sheet on a 30°C rapid cooling roller under 10kV electrostatic adsorption. The cast sheet is then preheated on the roller at 50-60°C and subjected to a 1.05-fold longitudinal stretch. It then enters a transverse stretching oven and is preheated with hot air at 70-80°C before undergoing a 4.6-fold transverse stretch. Finally, it undergoes a heat-setting treatment at 90°C and a cooling treatment at 30°C to obtain the bio-based copolyester shrink film. The scraps from the online edge trimming and slitting of this bio-based copolyester shrink film are crushed, granulated, and reused in layer B.

[0062] Example 2: This example provides a bio-based copolyester shrink film for medical device packaging and its preparation method, including the following steps:

[0063] With a density of 1.38 g / cm³ 3 A nano-silica-modified furanyl dicarboxylic acid copolyester with a melting point of 202℃, an intrinsic viscosity of 0.82 dl / g, and a terminal carboxyl group content of 12 mmol / kg was used as the A layer material. This material was added to a twin-screw extruder with an aspect ratio of 40:1 and melted at 210℃. The resulting melt served as the inner and outer surface A layer of the bio-based copolyester shrink film. The nano-silica accounted for 0.4% of the A layer resin mass, and the silica particle size was 100 nm. The A layer thickness comprised 15% of the total film thickness.

[0064] With a density of 1.38 g / cm³ 3 PEFG with a melting point of 202℃, intrinsic viscosity of 0.82 dl / g, and terminal carboxyl group content of 12 mmol / kg, and PEFG with a melting point of 120℃ and density of 1.23 g / cm³ are compared with PEFG with a melting point of 120℃ and density of 1.23 g / cm³. 3A mixture of PBAT with a terminal carboxyl group content of 12 mmol / kg and a melt index of 4.2 g / 10 min (190℃ / 2.16 g) in a mass percentage ratio of 80:20 was used as the C-layer material. This mixture was added to a twin-screw extruder with an aspect ratio of 40:1 and melted at 210℃. The resulting melt was used as the core layer C of the bio-based copolyester shrink film. The C-layer thickness accounted for 75% of the total film thickness.

[0065] The A layer material and the C layer material are mixed in the ratio of the actual A layer thickness and the C layer thickness, and then added to a twin-screw extruder to melt and form the B layer; the thickness of the B layer accounts for 10% of the total film thickness;

[0066] The above-mentioned ABC three-layer melt is filtered through a 600-mesh filter according to a mass percentage of 15 / 10 / 75, and then enters the ABCBA five-layer adapter and flows out through the ABCBA five-layer coat hanger-type die head; wherein, the ratio of ABCBA is 7.5:5:75:5:75:7.5.

[0067] The five fluid layers described above are formed into a cast sheet on a 35°C quenching roller under 9.5kV electrostatic adsorption. The cast sheet is then preheated on the roller at 55-65°C and subjected to a 1.1x longitudinal stretch. It then enters a transverse stretching oven where it is preheated with hot air at 65-75°C and subjected to a 4.8x transverse stretch. Finally, it undergoes heat setting at 80°C and cooling at 30°C to obtain the bio-based copolyester shrink film. The scraps from the online edge trimming and slitting of this bio-based copolyester shrink film are crushed, granulated, and reused in layer B.

[0068] Example 3: This example provides a bio-based copolyester shrink film for medical device packaging and its preparation method, including the following steps:

[0069] With a density of 1.39 g / cm³ 3 A nano-silica-modified furanyl dicarboxylic acid copolyester with a melting point of 206℃, an intrinsic viscosity of 0.85 dl / g, and a terminal carboxyl group content of 14 mmol / kg was used as the A layer material. This material was added to a twin-screw extruder with an aspect ratio of 42:1 and melted at 225℃. The resulting melt served as the inner and outer surface A layer of the bio-based copolyester shrink film. The mass of the nano-silica was 0.2% of the A layer resin mass, and the particle size of the silica was 50 nm. The thickness of the A layer accounted for 20% of the total film thickness.

[0070] With a density of 1.39 g / cm³ 3 PETG with a melting point of 208℃, intrinsic viscosity of 0.85 dl / g, and end-carboxyl group content of 15 mmol / kg, and PETG with a melting point of 125℃ and density of 1.25 g / cm³ are compared. 3PBAT with carboxyl end group content of 15 mmol / kg and melt index of 4.5 g / 10 min (190℃ / 2.16 g) were mixed together in a mass percentage of 70:30 to obtain a mixture as the C layer material, which was added into a twin-screw extruder with a length-diameter ratio of 42:1 and melted at a temperature of 225℃ to obtain a melt as the core layer C layer of the bio-based copolyester shrink film; the thickness of the C layer accounted for 70% of the total film thickness;

[0071] The mixing ratio of the A layer material and the C layer material was mixed according to the ratio of the actual A layer thickness and the C layer thickness, and then added into a twin-screw extruder for melting as the B layer; the thickness of the B layer accounted for 10% of the total film thickness;

[0072] The ABC three-layer melt was filtered through a filter screen filter with a filtering precision of 700 mesh, and then entered an ABCBA five-layer adapter and flowed out of an ABCBA five-layer hanger die; wherein the proportion of ABCBA was 10:5:70:10:5;

[0073] The five-layer fluid was formed into a cast sheet on a quenching roller at 40℃ under electrostatic adsorption of 9kV, and then the cast sheet was preheated by a roller at 70-80℃, followed by longitudinal stretching by 1.5 times, preheating by hot air at 80-90℃ in a transverse stretching oven, followed by transverse stretching by 4.9 times, and finally heat setting treatment at 70℃ and cooling treatment at 40℃ to obtain the bio-based copolyester shrink film. The edge and corner scraps after on-line trimming and slitting of the bio-based copolyester shrink film were crushed and granulated to enter the B layer for repeated use.

[0074] Comparative Example 1: This comparative example provides a petroleum-based PETG shrink film and a preparation method thereof, comprising the following steps:

[0075] The petroleum-based PETG chips (brand SK 2012) of the Korean SK Chemicals company and the petroleum-based anti-sticking PETG chips (brand MB 13) of the Sukano company were mixed in a proportion of 99.5%:0.5% and then added into a twin-screw extruder for melting to obtain a uniform melt. The melt was filtered through a filter screen filter with a filtering precision of 800 mesh and an adapter, and then flowed out of a single-layer hanger die. The cast sheet was formed on a quenching roller at a temperature of 40℃ under electrostatic adsorption of 9kV, and then the cast sheet was preheated by a roller at 70-80℃, followed by longitudinal stretching by 1.05 times, preheating by hot air at 80-90℃ in a transverse stretching oven, followed by transverse stretching by 4.9 times, and finally heat setting treatment at 70℃ and cooling treatment at 40℃ to obtain the petroleum-based PETG shrink film.

[0076] Test Example 1: The shrinkage, puncture resistance and hand properties of the different types of shrink films prepared in Examples 1-3 and Comparative Example 1 were tested.

[0077] As shown in Table 1, the bio-based copolyester shrink films prepared in Examples 1-3 of the present application have more than 50% bio-based content, and have similar shrinkage to the petroleum-based PETG shrink film prepared in Comparative Example 1, but the films prepared in the present application have higher puncture resistance.

[0078] Table 1 Performance Comparison

[0079]

[0080]

[0081] The above description is merely preferred embodiments of the present application, and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, and the like made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A bio-based copolyester shrink film for medical device packaging, characterized in that, The film has a five-layer structure of ABCBA, where layer A is the inner and outer outer layers, layer C is the core layer, and layer B is the intermediate adhesive layer between layer A and layer C. Among them, layer A is a bio-based furan dicarboxylic acid copolyester resin modified with nano-silica, layer C is a mixed resin of bio-based furan dicarboxylic acid copolyester PEFG and poly(butylene adipate / terephthalate) PBAT, and layer B is a mixture of layer A and layer C. The mass ratio of PEFG resin to PBAT resin in the C-layer material is 60-90:10-40; The nano-silica-modified bio-based furanyl dicarboxylic acid copolyester resin is obtained by copolymerization modification of bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano-silica, wherein the mass ratio of bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano-silica is 60-80%:20-40%:5-15%:0.2-1.5%, and the sum of the mass percentages of each substance is 100%. The bio-based furanyl dicarboxylic acid copolyester is obtained by copolymerization modification of bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, and neopentyl glycol, wherein the mass ratio of bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, and neopentyl glycol is 60-80%: 20-40%: 5-15%, and the sum of the mass percentages of each substance is 100%.

2. The bio-based copolyester shrink film for medical device packaging as described in claim 1, characterized in that, The thickness of the bio-based copolyester shrink film is 20-100 μm, and the thickness ratio of the five ABCBA layers is 5-10:5-10:60-80:5-10:5-10; The particle size of the nano-silica in the A layer is 10-100 nm; the mass ratio of the A layer to the C layer in the B layer is 10-20:60-80.

3. The method for preparing the bio-based copolyester shrink film for medical device packaging according to any one of claims 1-2, characterized in that, Includes the following steps: S1. Bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano silica are copolymerized to obtain nano silica-modified bio-based furanyl dicarboxylic acid copolyester resin chips, and then the outer surface layer A is prepared. S2. Bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, and neopentyl glycol are copolymerized to obtain bio-based furanyl dicarboxylic acid copolyester chips, which are then mixed with poly(adipic acid / butyl terephthalate) to obtain the core layer C. S3. Mix the outer layer A and the core layer C to obtain the intermediate adhesive layer B; S4. The outer layer A, the middle adhesive layer B, and the core layer C are adapted into five layers (ABCBA) to obtain a bio-based copolyester shrink film.

4. The preparation method according to claim 3, characterized in that, In step S1, the copolymerization modification is carried out using bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano silica as raw materials, and a copolymerization reaction occurs in the presence of a composite catalyst. Specifically, bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, neopentyl glycol and nano silica are first mixed, and then a composite catalyst is added to carry out the esterification reaction to obtain a stable esterification solution. The esterification solution was then subjected to a pre-condensation reaction to obtain a pre-condensation polymer; finally, the pre-condensation polymer was subjected to a negative pressure polymerization reaction to obtain a bio-based furan dicarboxylic acid copolyester modified with nano-silica. The composite catalyst is a mixture of antimony glycolate and tetrabutyl titanate, wherein the mass ratio of antimony glycolate to tetrabutyl titanate is 60-80:20-40; and the mass of the composite catalyst is 200-400 ppm. The esterification reaction is carried out at a temperature of 200-245℃ for a time of 30-90 min. The specific operation of the prepolymerization reaction is as follows: the melt is pumped evenly into the prepolymerization reactor through a 20-60 μm candle wick filter using a melt pump, and stirred at a speed of 50-200 r / min for 30-60 minutes using an anchor stirrer. The temperature is then continuously increased to 240-260℃, and the reaction is carried out under a vacuum of 500 Pa for 15 minutes to obtain a prepolymer with a certain degree of polymerization. The specific operation of the negative pressure polymerization reaction is as follows: the prepolymer is pressed into the polycondensation reactor after passing through a 20-40 μm candle wick filter, and then the temperature is continuously increased to 270-290℃. The negative pressure polymerization reaction is carried out under a vacuum of 10-50 Pa, and the reaction time is controlled to be 3-6 hours. Then, it is obtained by underwater pelleting and drying.

5. The preparation method according to claim 3, characterized in that, In step S2, the copolymerization modification is carried out using bio-based furanyl dicarboxylic acid, bio-based ethylene glycol, and neopentyl glycol as raw materials in the presence of a composite catalyst. Specifically, bio-based furanyl dicarboxylic acid, bio-based ethylene glycol and neopentyl glycol are first mixed, and then a composite catalyst is added to carry out the esterification reaction to obtain a stable esterification solution. The esterification solution was then subjected to a pre-condensation reaction to obtain a pre-condensation polymer; finally, the pre-condensation polymer was subjected to a negative pressure polymerization reaction to obtain a bio-based furan dicarboxylic acid copolyester. The composite catalyst is a mixture of antimony glycolate and tetrabutyl titanate, wherein the mass ratio of antimony glycolate to tetrabutyl titanate is 60-80:20-40; and the mass of the composite catalyst is 200-400 ppm. The esterification reaction is carried out at a temperature of 200-245℃ for a time of 30-90 min. The specific operation of the prepolymerization reaction is as follows: the melt is pumped evenly into the prepolymerization reactor through a 20-60 μm candle wick filter using a melt pump, and stirred at a speed of 50-200 r / min for 30-60 minutes using an anchor stirrer. The temperature is then continuously increased to 240-260℃, and the reaction is carried out under a vacuum of 500 Pa for 15 minutes to obtain a prepolymer with a certain degree of polymerization. The specific operation of the negative pressure polymerization reaction is as follows: the prepolymer is pressed into the polycondensation reactor after passing through a 20-40 μm candle wick filter, and then the temperature is continuously increased to 270-290℃. The negative pressure polymerization reaction is carried out under a vacuum of 10-50 Pa, and the reaction time is controlled to be 3-6 hours. Then, it is obtained by underwater pelleting and drying.

6. The preparation method according to claim 3, characterized in that, In step S1, the outer layer A is obtained by melting and plasticizing bio-based furanyl dicarboxylic acid copolyester chips modified with nano-silica using a twin-screw extruder; the extrusion temperature of the nano-silica modified furanyl dicarboxylic acid copolyester resin chips is 190-230℃. In step S2, the core layer C is obtained by mixing bio-based furanyl dicarboxylic acid copolyester chips with poly(adipate adipate / butyl terephthalate) and then melting and plasticizing the mixture in a twin-screw extruder; the extrusion temperature of the mixed resin of bio-based furanyl dicarboxylic acid copolyester chips and poly(adipate adipate / butyl terephthalate) is 180-230℃. In step S3, the intermediate adhesive layer B is obtained by mixing the A layer material and the C layer material and then melting and plasticizing them in a twin-screw extruder; the extrusion temperature of the mixture of the intermediate adhesive layer B is 180-230℃. The twin-screw extruder has a length-to-diameter ratio of 38-42:1 and a vacuum degree of 10-80 Pa.

7. The preparation method according to claim 3, characterized in that, In step S4, the outer layer A, the middle adhesive layer B, and the core layer C are filtered through filters and then enter the ABCBA five-layer adapter. Finally, they flow out from the ABCBA five-layer die head and form a casting on the rapid cooling roller. The casting is then preheated by the roller and stretched longitudinally at a certain ratio. After entering the oven, it is preheated with hot air and stretched transversely at a certain ratio. Finally, it undergoes heat setting and cooling treatment at a certain temperature to obtain the bio-based copolyester shrink film.

8. The preparation method according to claim 7, characterized in that, The filter is a five-layer filter with a filter precision of 600-800 mesh. The temperature of the quenching roller is 30-40℃; The casting is carried out under electrostatic adsorption conditions via an electrostatic adsorption wire, wherein the voltage is set to 9-12 kV and the current is set to 5-10 mA. The preheating temperature of the roller is 60-80℃; The longitudinal stretching ratio is 1.01-2.0 times, and the longitudinal stretching temperature is 50-80℃; The preheating temperature of the hot air in the oven during the transverse stretching is 120-70℃; the preheating is carried out by a gradual cooling process. The lateral stretching ratio is 4.5-6.0 times, and the lateral stretching temperature is 60-100 ℃; The temperature for the heat setting treatment is 60-100℃; The cooling process is performed at a temperature of 30-40°C.

9. The use of the bio-based copolyester shrink film for medical device packaging as described in any one of claims 1-2 in medical device packaging materials.

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