An antistatic PETG heat shrink film

Abstract

The present invention relates to the field of heat shrinkable films, and in particular to a kind of antistatic PETG heat shrinkable film.PETG heat shrinkable film is calculated according to parts by weight, including the following components: 100 parts of PETG resins, 2 6 parts of antiblocking agents, 2 5 parts of lubricants, 1 5 parts of antistatic modifiers, 1 2 parts of antioxidants and 0.5 1 parts of light stabilizers. The present invention, in the preparation process of PETG heat shrinkable film, introduces novel borate antistatic agent, which is synthesized using tris (2 carboxyethyl) isocyanurate and 4 aminophenylboronic acid pinacol ester as raw materials, compared to traditional antistatic agent, not only antistatic performance is better, and thermal stability is significantly improved, and the phenomenon that local deformation or circular arc-shaped shrinkage is poor occurs when PETG heat shrinkable film shrinks at an uneven interface is reduced.

Description

Technical Field

[0001] The invention relates to the field of heat shrinkable films, in particular to an antistatic PETG heat shrinkable film. Background Art

[0002] Heat shrink film refers to labels used to wrap around containers, such as plastic and glass bottles. Heat shrink film boasts excellent gloss, conformability, and shrinkage properties. Its gloss and shrinkage make packaging designs more vivid, stand out more prominently on supermarket shelves, and create an unexpected shelf effect, leading to its widespread use in container packaging.

[0003] Existing heat shrink film materials for labels mainly include polyvinyl chloride (PVC), polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG), and oriented polystyrene (OPS). PVC heat shrink film boasts high tensile strength, high elongation, good self-adhesion, and high transparency. However, it also has drawbacks such as the generation of highly toxic dioxins during recycling and poor environmental performance, leading to its gradual ban. OPS heat shrink film offers high strength, high rigidity, stable form, good gloss and transparency, and is easy to process, easily colorable, printable, and boasts extremely high resolution. However, it is relatively expensive and requires specialized solvent inks for printing. PETG heat shrink film is non-toxic, odorless, high-strength, high heat shrinkage, good optical properties, mechanical extensibility, and aesthetically pleasing packaging, leading to rapid growth in the use of both OPS and PETG heat shrink films.

[0004] PETG heat-shrink film has successfully replaced polyvinyl chloride heat-shrink film as the most ideal heat-shrink packaging material due to its high shrinkage rate, good transparency, non-toxicity, odorlessness, and excellent mechanical properties. However, PETG heat-shrink film lacks antistatic properties, and currently used antistatic agents on the market do not perform as expected on PETG heat-shrink film. Furthermore, traditional antistatic agents tend to be unevenly dispersed within PETG heat-shrink film and have poor thermal stability, which can easily lead to localized deformation or arc-shaped shrinkage defects during uneven interface shrinkage. Summary of the Invention

[0005] In view of the problems existing in the prior art, the object of the present invention is to provide an antistatic PETG heat shrinkable film.

[0006] The purpose of the present invention is achieved by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides an antistatic PETG heat shrinkable film, which comprises the following components, calculated by weight:

[0008] 100 parts of PETG resin, 2-6 parts of anti-blocking agent, 2-5 parts of lubricant, 1-5 parts of antistatic modifier, 1-2 parts of antioxidant and 0.5-1 part of light stabilizer.

[0009] Preferably, the density of the PETG resin is 1.22-1.31 g / cm 3 , more preferably 1.27 g / cm 3 ; Melt index is 8-12g / 10min (230℃, 2.16kg).

[0010] Preferably, the anti-adhesion agent is surface silanized silicon dioxide with a particle size of 0.5-5 μm, more preferably 3 μm.

[0011] Preferably, the preparation method of the surface silanized silicon dioxide comprises:

[0012] Silica nanopowder, coupling agent KH-550 and 50wt% ethanol solution are mixed, refluxed for 2-6 hours, filtered and dried to obtain surface silanized silica; wherein the mass ratio of silica nanopowder, coupling agent KH-550 and ethanol solution is 1:0.1-0.3:5-10.

[0013] Preferably, the lubricant is a mixture of one or more of zinc stearate, calcium stearate, polyethylene wax, and paraffin wax.

[0014] Preferably, the preparation method of the antistatic modifier comprises:

[0015] S1. Add dichloromethane solvent into a flask, introduce nitrogen as a protective gas, then add tris(2-carboxyethyl)isocyanurate and N,N'-dicyclohexylcarbodiimide (DCC), stir in an ice-water bath for 0.5-1.5 h, then warm to room temperature, add N-hydroxysuccinimide (NHS), and stir for 1-2 h to obtain an intermediate reaction solution;

[0016] S2. Slowly add 4-aminophenylboronic acid pinacol ester to the intermediate reaction solution. After complete addition, stir at room temperature for 4-8 hours, remove the solvent under reduced pressure, and purify by silica gel column chromatography to obtain an antistatic modifier.

[0017] Preferably, in the preparation process of the antistatic modifier, the mass ratio of tris(2-carboxyethyl)isocyanurate, 4-aminophenylboronic acid pinacol ester, N-hydroxysuccinimide (NHS), N,N'-dicyclohexylcarbodiimide (DCC) and dichloromethane is 0.2-0.4:0.58-0.83:0.7-0.9:0.4-0.6:3-8.

[0018] Preferably, in the preparation process of the antistatic modifier, the silica gel column is a C18 column (200-300 mesh), and the eluent is a mixture of n-hexane and ethyl acetate in a volume ratio of 2-5:1.

[0019] Preferably, the antioxidant is a mixture of a primary antioxidant and a secondary antioxidant in a mass ratio of 1:1-4; wherein the primary antioxidant is one of antioxidant 1010, antioxidant 1076, antioxidant 245, and antioxidant 1098; and the secondary antioxidant is antioxidant 168 or antioxidant 126. More preferably, the primary antioxidant is antioxidant 1010, and the secondary antioxidant is antioxidant 168.

[0020] Preferably, the light stabilizer is a mixture of one or more of UV-770, UV-944, UV-326, UV-328, and UV-1577.

[0021] In a second aspect, the present invention provides a method for preparing an antistatic PETG heat shrinkable film, comprising the following steps:

[0022] Step 1: Weigh the raw materials according to their weight and dry them in an oven to constant weight;

[0023] Step 2: Place all raw materials in a high-speed blender and stir evenly to obtain a uniform mixture;

[0024] Step 3, placing the uniform mixture into a twin-screw extruder and performing melt granulation to obtain PETG masterbatch;

[0025] Step 4: placing the PETG masterbatch in a single-screw extruder, casting the sheet, biaxially stretching the film, and shaping the film to obtain an antistatic PETG heat shrinkable film.

[0026] Preferably, in step 2, the stirring speed is 200-300 rpm, and the stirring time is 10-15 min.

[0027] Preferably, in step 3, the melting temperature is 250-290° C., the screw speed is 150-200 rpm, and the vacuum exhaust pressure is ≤100 Pa.

[0028] Preferably, in step 4, the slab is cast by casting the melt into a slab at a casting temperature of 25-60°C.

[0029] Preferably, in step 4, the biaxial stretching film forming includes longitudinal stretching (MDO) and transverse stretching (TDO); wherein the stretching temperature of the longitudinal stretching is 80-100°C, and the stretching ratio is 1-3 times; the stretching temperature of the transverse stretching is 80-100°C, and the stretching ratio is 3.5-4.5 times; and the setting temperature is 35-50°C.

[0030] Preferably, in step 4, the thickness of the antistatic PETG heat shrinkable film obtained is 30-50 μm.

[0031] The beneficial effects of the present invention are:

[0032] 1. In the preparation process of the PETG heat shrinkable film, the present invention introduces a new borate antistatic agent, which is synthesized using tris (2-carboxyethyl) isocyanurate and 4-aminophenylboronic acid pinacol ester as raw materials. Compared with traditional antistatic agents, the present invention not only has better antistatic performance, but also significantly improves thermal stability, thereby reducing the phenomenon of local deformation or arc-shaped poor shrinkage of the PETG heat shrinkable film during uneven interface shrinkage.

[0033] 2. Borate compounds can be used as environmentally friendly antistatic agents because their polar borate groups absorb moisture to form a conductive layer, thereby reducing surface resistance. However, currently available borate antistatic agents (such as triethanolamine borate) generally have poor thermal stability and insufficient compatibility with resins, resulting in mediocre antistatic performance. The present invention uses 4-aminophenylboronic acid pinacol ester and tris(2-carboxyethyl)isocyanurate as raw materials and undergoes an amidation reaction via a DCC-NHS system. The resulting antistatic agent contains an amide group, a phenylboronic acid pinacol ester structure, and an isocyanurate structure. Compared to traditional borate antistatic agents, it not only has better compatibility with resins but also significantly improves thermal stability, thereby improving the poor shrinkage of PETG heat-shrinkable film. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the presence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships, without substantially changing the technical content, should also be regarded as the scope of the present invention.

[0035] In order to better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0036] The present invention will be further described below with reference to the following examples.

[0037] Example 1

[0038] An antistatic PETG heat shrinkable film, calculated by weight, comprises the following components:

[0039] 100 parts of PETG resin, 4 parts of anti-blocking agent, 3 parts of lubricant, 3.5 parts of antistatic modifier, 1 part of antioxidant and 0.6 parts of light stabilizer.

[0040] Among them, the density of PETG resin is 1.27g / cm 3 The melt index is 10 g / 10 min (230°C, 2.16 kg); the lubricant is zinc stearate; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:3; and the light stabilizer is UV-944.

[0041] The anti-adhesion agent is surface silanized silicon dioxide with a particle size of 3 μm. The preparation method includes:

[0042] Silica nanopowder, coupling agent KH-550 and 50wt% ethanol solution were mixed, refluxed for 4 hours, filtered and dried to obtain surface silanized silica; wherein the mass ratio of silica nanopowder, coupling agent KH-550 and ethanol solution was 1:0.2:8.

[0043] The preparation method of the antistatic modifier includes:

[0044] S1. Add 5 g of dichloromethane (a solvent) into a flask, introduce nitrogen as a protective gas, then add 0.3 g of tris(2-carboxyethyl)isocyanurate and 0.5 g of N,N'-dicyclohexylcarbodiimide (DCC), stir in an ice-water bath for 1 h, then warm to room temperature, add 0.8 g of N-hydroxysuccinimide (NHS), and stir for 1.5 h to obtain an intermediate reaction solution;

[0045] S2. Slowly add 0.71 g of 4-aminophenylboronic acid pinacol ester to the intermediate reaction solution. After complete addition, stir at room temperature for 6 hours, remove the solvent under reduced pressure, and chromatograph on a C18 silica gel column (250 mesh) with n-hexane and ethyl acetate in a volume ratio of 3:1 as the eluent. After drying, obtain an antistatic modifier.

[0046] The preparation method of the above-mentioned antistatic PETG heat shrinkable film comprises the following steps:

[0047] Step 1: Weigh the raw materials according to their weight and dry them in an oven to constant weight;

[0048] Step 2: Place all the raw materials in a high-speed stirrer and stir at 300 rpm for 10 minutes to obtain a uniform mixture;

[0049] Step 3: placing the uniform mixture in a twin-screw extruder, undergoing melting treatment, with a melting range of 250-290° C., a screw speed of 200 rpm, and a vacuum exhaust pressure of ≤100 Pa, and granulating to obtain PETG masterbatch;

[0050] Step 4: placing the PETG masterbatch in a single-screw extruder, casting the sheet at a temperature of 50° C., and biaxially stretching the film; wherein the longitudinal stretching temperature is 90° C. and the stretching ratio is 2 times; the transverse stretching temperature is 100° C. and the stretching ratio is 4 times; and then shaping at a temperature of 45° C. to obtain a PETG heat shrinkable film with a thickness of 40 μm.

[0051] Example 2

[0052] An antistatic PETG heat shrinkable film, calculated by weight, comprises the following components:

[0053] 100 parts of PETG resin, 2 parts of anti-blocking agent, 5 parts of lubricant, 1 part of antistatic modifier, 1 part of antioxidant and 0.5 parts of light stabilizer.

[0054] Among them, the density of PETG resin is 1.27g / cm 3 The melt index is 10 g / 10 min (230°C, 2.16 kg); the lubricant is calcium stearate; the antioxidant is a mixture of antioxidant 1076 and antioxidant 126 in a mass ratio of 1:1; and the light stabilizer is UV-770.

[0055] The anti-adhesion agent is surface silanized silicon dioxide with a particle size of 3 μm. The preparation method includes:

[0056] Silica nanopowder, coupling agent KH-550 and 50wt% ethanol solution were mixed, refluxed for 2h, filtered and dried to obtain surface silanized silica; wherein the mass ratio of silica nanopowder, coupling agent KH-550 and ethanol solution was 1:0.1:5.

[0057] The preparation method of the antistatic modifier includes:

[0058] S1. Add 3 g of dichloromethane (a solvent) into a flask, introduce nitrogen as a protective gas, then add 0.2 g of tris(2-carboxyethyl)isocyanurate and 0.4 g of N,N'-dicyclohexylcarbodiimide (DCC), stir in an ice-water bath for 0.5 h, then warm to room temperature, add 0.7 g of N-hydroxysuccinimide (NHS), and stir for 1 h to obtain an intermediate reaction solution;

[0059] S2. Slowly add 0.58 g of 4-aminophenylboronic acid pinacol ester to the intermediate reaction solution. After complete addition, stir at room temperature for 4-8 hours, remove the solvent under reduced pressure, and chromatograph on a C18 silica gel column (250 mesh) with an eluent of n-hexane and ethyl acetate in a volume ratio of 2:1. After drying, obtain an antistatic modifier.

[0060] The preparation method of the above-mentioned antistatic PETG heat shrinkable film comprises the following steps:

[0061] Step 1: Weigh the raw materials according to their weight and dry them in an oven to constant weight;

[0062] Step 2: Place all the raw materials in a high-speed stirrer and stir at 200 rpm for 10 minutes to obtain a uniform mixture;

[0063] Step 3: placing the uniform mixture in a twin-screw extruder, undergoing melting treatment, with a melting range of 250-290° C., a screw speed of 150-200 rpm, and a vacuum exhaust pressure of ≤100 Pa, and granulating to obtain PETG masterbatch;

[0064] Step 4: Place the PETG masterbatch in a single-screw extruder, cast it into sheets at a temperature of 25°C, and then biaxially stretch it into a film. The longitudinal stretching temperature is 80°C, and the stretching ratio is 1x; the transverse stretching temperature is 80°C, and the stretching ratio is 3.5x. The film is then shaped at 35°C to obtain a PETG heat-shrinkable film with a thickness of 30 μm.

[0065] Example 3

[0066] An antistatic PETG heat shrinkable film, calculated by weight, comprises the following components:

[0067] 100 parts of PETG resin, 6 parts of anti-blocking agent, 2 parts of lubricant, 5 parts of antistatic modifier, 2 parts of antioxidant and 1 part of light stabilizer.

[0068] Among them, the density of PETG resin is 1.27g / cm 3 The melt index is 10 g / 10 min (230°C, 2.16 kg). The lubricant is polyethylene wax. The antioxidant is a mixture of antioxidant 1098 and antioxidant 168 in a mass ratio of 1:4. The light stabilizer is UV-328.

[0069] The anti-adhesion agent is surface silanized silicon dioxide with a particle size of 3 μm. The preparation method includes:

[0070] Silica nanopowder, coupling agent KH-550 and 50wt% ethanol solution were mixed, refluxed for 2-6 hours, filtered and dried to obtain surface silanized silica; wherein the mass ratio of silica nanopowder, coupling agent KH-550 and ethanol solution was 1:0.3:10.

[0071] The preparation method of the antistatic modifier includes:

[0072] S1. Add 3-8 g of dichloromethane (a solvent) into a flask, introduce nitrogen as a protective gas, then add 0.4 g of tris(2-carboxyethyl)isocyanurate and 0.6 g of N,N'-dicyclohexylcarbodiimide (DCC), stir in an ice-water bath for 1.5 h, then warm to room temperature, add 0.9 g of N-hydroxysuccinimide (NHS), and stir for 2 h to obtain an intermediate reaction solution;

[0073] S2. Slowly add 0.83 g of 4-aminophenylboronic acid pinacol ester to the intermediate reaction solution. After complete addition, stir at room temperature for 8 hours, remove the solvent under reduced pressure, and chromatograph on a C18 silica gel column (250 mesh) with n-hexane and ethyl acetate in a volume ratio of 5:1 as the eluent. After drying, obtain an antistatic modifier.

[0074] The preparation method of the above-mentioned antistatic PETG heat shrinkable film comprises the following steps:

[0075] Step 1: Weigh the raw materials according to their weight and dry them in an oven to constant weight;

[0076] Step 2: Place all the raw materials in a high-speed blender and stir at 300 rpm for 15 minutes to obtain a uniform mixture;

[0077] Step 3: placing the uniform mixture in a twin-screw extruder, subjecting it to melting treatment, with a melting range of 290° C., a screw speed of 200 rpm, and a vacuum exhaust pressure of ≤100 Pa, and granulating to obtain PETG masterbatch;

[0078] Step 4: The PETG masterbatch is placed in a single-screw extruder, cast at 60°C, and then biaxially stretched to form a film. The longitudinal stretching temperature is 100°C, with a stretch ratio of 3 times; the transverse stretching temperature is 100°C, with a stretch ratio of 4.5 times. The film is then shaped at 50°C to obtain a PETG heat-shrinkable film with a thickness of 50 μm.

[0079] Comparative Example 1

[0080] A PETG heat shrinkable film, which differs from Example 1 in that the antistatic modifier is replaced by triethanolamine borate, and the other components and preparation method are the same as those in Example 1.

[0081] Comparative Example 2

[0082] A PETG heat shrinkable film, which differs from Example 1 in that the antistatic modifier is replaced by 4-aminophenylboronic acid pinacol ester, and other components and preparation methods are the same as those in Example 1.

[0083] Comparative Example 3

[0084] A PETG heat shrinkable film, which differs from Example 1 in that the antistatic modifier is replaced by tris(2-carboxyethyl)isocyanurate, and other components and preparation methods are the same as those in Example 1.

[0085] Experimental testing

[0086] The heat shrinkage rate, strength and antistatic properties of the PETG heat shrinkable films prepared in Example 1 and Comparative Examples 1-3 were tested.

[0087] The tensile strength test refers to the standard GB / T 19787-2005 (tensile speed 50 mm / min); the thermal shrinkage rate and shrinkage stress test refer to the standard ISO 14616 (110°C hot air treatment for 20 seconds); the surface resistivity test refers to the standard ASTM D257 (test voltage: 500 V DC (normal value)).

[0088] The test results are shown in Table 1 below:

[0089] Table 1 PETG heat shrink film test results

[0090]

[0091] As can be seen, compared with the other comparative examples, the PETG heat-shrinkable film prepared in Example 1 of the present invention has a tensile strength of 168 MPa in the transverse direction, a tensile strength of 57 MPa in the longitudinal direction, a shrinkage stress of 6.4 N / 15 mm, and a transverse heat shrinkage rate of 83%. This demonstrates high mechanical strength and excellent thermal stability, which can largely avoid the phenomenon of poor shrinkage. In addition, compared with Comparative Example 1, the surface resistivity of the PETG heat-shrinkable film prepared in Example 1 is lower, indicating that its antistatic properties are also superior.

[0092] In the description of this specification, reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0093] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An antistatic PETG heat shrinkable film, characterized in that, Calculated by weight, it includes the following ingredients: 100 parts of PETG resin, 2-6 parts of anti-blocking agent, 2-5 parts of lubricant, 1-5 parts of antistatic modifier, 1-2 parts of antioxidant and 0.5-1 part of light stabilizer; The anti-adhesion agent is surface silanized silicon dioxide; the antistatic modifier is a product obtained by amidation reaction of tris(2-carboxyethyl)isocyanurate and 4-aminophenylboronic acid pinacol ester; The preparation method of the antistatic modifier comprises: S1. Add dichloromethane solvent into a flask, introduce nitrogen as a protective gas, then add tris(2-carboxyethyl)isocyanurate and N,N'-dicyclohexylcarbodiimide, stir in an ice-water bath for 0.5-1.5 h, then warm to room temperature, add N-hydroxysuccinimide, and stir for 1-2 h to obtain an intermediate reaction solution; S2. Slowly add 4-aminophenylboronic acid pinacol ester to the intermediate reaction solution. After complete addition, stir at room temperature for 4-8 hours, remove the solvent under reduced pressure, and purify by silica gel column chromatography to obtain an antistatic modifier; During the preparation of the antistatic modifier, the mass ratio of tris(2-carboxyethyl)isocyanurate to 4-aminophenylboronic acid pinacol ester is 0.2-0.4:0.58-0.

83.

2. An antistatic PETG heat shrinkable film according to claim 1, characterized in that, The preparation method of the surface silanized silicon dioxide comprises: Silica nanopowder, coupling agent KH-550 and 50wt% ethanol solution are mixed, refluxed for 2-6 hours, filtered and dried to obtain surface silanized silica; wherein the mass ratio of silica nanopowder, coupling agent KH-550 and ethanol solution is 1:0.1-0.3:5-10.

3. An antistatic PETG heat shrinkable film according to claim 1, characterized in that, The lubricant is a mixture of one or more of zinc stearate, calcium stearate, polyethylene wax and paraffin wax.

4. An antistatic PETG heat shrinkable film according to claim 1, characterized in that, The antioxidant is obtained by mixing a main antioxidant and a secondary antioxidant in a mass ratio of 1:1-4; wherein the main antioxidant is one of antioxidant 1010, antioxidant 1076, antioxidant 245, and antioxidant 1098; and the secondary antioxidant is antioxidant 168 or antioxidant 126.

5. An antistatic PETG heat shrinkable film according to claim 1, characterized in that, The light stabilizer is a mixture of one or more of UV-770, UV-944, UV-326, UV-328, and UV-1577.

6. A method for preparing the antistatic PETG heat shrinkable film according to claim 1, characterized in that: The following steps are involved: Step 1: Weigh the raw materials according to their weight and dry them in an oven to constant weight; Step 2: Place all raw materials in a high-speed blender and stir evenly to obtain a uniform mixture; Step 3, placing the uniform mixture into a twin-screw extruder, and performing melt granulation to obtain PETG masterbatch; Step 4: placing the PETG masterbatch in a single-screw extruder, casting the sheet, biaxially stretching the film, and shaping the film to obtain an antistatic PETG heat shrinkable film.

7. The method for preparing an antistatic PETG heat shrinkable film according to claim 6, wherein: In the step 3, the melting range is 250-290° C., the screw speed is 150-200 rpm, and the vacuum exhaust pressure is ≤100 Pa.

8. The method for preparing an antistatic PETG heat shrinkable film according to claim 6, wherein: In step 4, the biaxial stretching film forming includes longitudinal stretching and transverse stretching; wherein, the stretching temperature of the longitudinal stretching is 80-100°C, and the stretching ratio is 1-3 times; the stretching temperature of the transverse stretching is 80-100°C, and the stretching ratio is 3.5-4.5 times; and the setting temperature is 35-50°C.

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