Milky white PETG shrink film and preparation method thereof

Abstract

The milky white PETG shrink film is characterized in that the milky white PETG shrink film comprises an outer surface layer, a first bonding layer, a middle layer, a second bonding layer and an inner surface layer, the first bonding layer is used for bonding the outer surface layer and the middle layer, and the second bonding layer is used for bonding the middle layer and the inner surface layer; wherein the inner surface layer is prepared by uniformly mixing a slow-release antibacterial layer nano TiO2 antibacterial master batch with PETG master batch according to a certain adding amount, the outer surface layer is a PETG layer, the middle layer is a PVDC layer, and the first bonding layer and the second bonding layer are EVA layers. The invention also provides a preparation method of the milky white PETG shrink film, so that the milky white PETG shrink film has an antibacterial effect, and the antibacterial effect of the milky white PETG shrink film is enhanced along with the increase of the addition amount of the nano TiO2.

Description

Technical Field

[0001] The invention belongs to the technical field of shrinkage films and relates to a milky white PETG shrinkage film and a preparation method thereof. Background Art

[0002] PETG is a non-crystalline copolyester. During its production process, a certain amount of ethylene glycol is replaced by 1,4-cyclohexanedimethanol (CHDM), which can prevent crystallization and improve processing and transparency.

[0003] PETG heat shrink film is non-toxic, odorless, high-strength, high heat shrinkage rate, and beautiful packaging effect. The biggest advantage of PETG polyester film is its good heat sealing performance. At the same time, its optical properties and mechanical extensibility are very good. PETG has passed the US FDA's food contact standards and can be used in food and personal health care product packaging, medical and health equipment food and other fields, and can also be used for electronic device packaging. It has international EU ROHS, REACH certification and US food FDA certification, and meets environmental protection and recycling requirements.

[0004] When PETG heat shrinkable film is used in the food field, its antibacterial property must be taken seriously. Therefore, the present application proposes a PETG heat shrinkable film having an antibacterial effect. Summary of the invention

[0005] The object of the present invention is to provide a milky white PETG shrink film and a preparation method thereof, to solve the above problems.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A milky white PETG shrink film, characterized in that it comprises an outer layer, a first adhesive layer, an intermediate layer, a second adhesive layer and an inner layer, wherein the first adhesive layer is used to bond the outer layer and the intermediate layer, and the second adhesive layer is used to bond the intermediate layer and the inner layer, wherein the inner layer is a slow-release antibacterial layer of nano-TiO 2 The antibacterial masterbatch is uniformly mixed with the PETG masterbatch in a certain amount, wherein the outer layer is a PETG layer, the middle layer is a PVDC layer, and the first bonding layer and the second bonding layer are EVA layers.

[0008] The present invention further provides that the thickness of the outer surface layer is 10-12 μm, the thickness of the middle layer is 30-40 μm, the thickness of the first adhesive layer and the second adhesive layer are both 10-12 μm, and the thickness of the inner surface layer is 12-15 μm.

[0009] The present invention is further arranged that the thicknesses of the outer layer, the first adhesive layer, the middle layer, the second adhesive layer and the inner layer are 10 μm, 10 μm, 30 μm, 10 μm and 12 μm.

[0010] The present invention further arranges that the nano-TiO 2 The addition amount of antibacterial masterbatch is 1-5%.

[0011] The present invention also provides a method for preparing a milky white PETG shrink film, characterized in that the shrink film is placed in corresponding hoppers according to the ratio of the outer layer thickness of 10-12 μm, the middle layer thickness of 30-40 μm, the first adhesive layer and the second adhesive layer thickness of 10-12 μm, and the inner layer thickness of 12-15 μm, wherein the slow-release antibacterial layer nano-TiO 2 The antibacterial masterbatch is added in an amount of 1-5% and mixed evenly with the PETG masterbatch; a blank tube is co-extruded from an extruder in the order of outer layer / first adhesive layer / middle layer / second adhesive layer / inner surface layer, and then the blank tube is subjected to cold air cooling treatment; the cooled blank tube is preheated to 40-90° C. by water vapor, and then the blank tube is transversely stretched and secondarily inflated by compressed air; a film obtained by the second inflating is pulled to a setting machine, and heated to a setting temperature of 50-80° C. to set the film, thereby obtaining a multi-layer co-extruded nano-TiO 2 Finished antibacterial PETG shrink packaging film.

[0012] The present invention further provides that the thickness ratios of the outer layer, the first adhesive layer, the middle layer, the second adhesive layer and the inner surface layer are 10 μm, 10 μm, 30 μm, 10 μm and 12 μm.

[0013] The present invention further provides that the slow-release antibacterial layer of nano-TiO 2 The addition amount of antibacterial masterbatch is 2%, 3% and 4% respectively.

[0014] The present invention further arranges that the temperature of each zone of the extruder for the outer surface layer and the inner surface layer is 150-165°C, and the temperature of each zone of the extruder for the middle layer, the first bonding layer and the second bonding layer is 160-166°C.

[0015] The present invention further provides that the cooled blank tube is preheated to 80° C. by using water vapor.

[0016] The present invention is further configured to draw the film obtained by the secondary inflation to a setting machine, and heat it to a setting temperature of 65° C. to perform setting treatment on the film.

[0017] The beneficial effects of the present invention are as follows: after adding a certain mass fraction of nano-TiO 2 It can effectively inhibit the growth of dominant spoilage bacteria in fresh meat such as Pseudomonas, Carnobacterium, Lactococcus and Lactobacillus, and with the addition of nano-TiO 2 The antibacterial effect of the heat shrinkable film increases with the increase of the added amount, and it is evenly distributed on the surface of the heat shrinkable film and has no significant effect on the transparency of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of Example 1 of the present invention.

[0019] Reference numerals: 10, outer surface layer; 20, first adhesive layer; 30, middle layer; 40, second adhesive layer; 50, inner surface layer; DETAILED DESCRIPTION

[0020] The following will explain the implementation methods of the present application in detail with reference to examples, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0021] Embodiment 1:

[0022] like Figure 1 As shown, this embodiment is a milky white PETG shrink film, comprising an outer layer 10, a first adhesive layer 20, an intermediate layer 30, a second adhesive layer 40 and an inner layer 50, wherein the first adhesive layer 20 is used to bond the outer layer 10 and the intermediate layer 30, and the second adhesive layer 40 is used to bond the intermediate layer 30 and the inner layer 50, wherein the inner layer 50 is a slow-release antibacterial layer of nano-TiO 2 The antibacterial masterbatch is uniformly mixed with the PETG masterbatch in a certain amount, wherein the outer layer 10 is a PETG layer, the middle layer 30 is a PVDC layer, and the first adhesive layer 20 and the second adhesive layer 40 are EVA layers.

[0023] In this embodiment, the thickness of the outer layer 10 is 10-12 μm, the thickness of the middle layer 30 is 30-40 μm, the thickness of the first adhesive layer 20 and the second adhesive layer 40 are both 10-12 μm, and the thickness of the inner layer 50 is 12-15 μm. Preferably, the thicknesses of the outer layer 10, the first adhesive layer 20, the middle layer 30, the second adhesive layer 40, and the inner layer 50 are 10 μm, 10 μm, 30 μm, 10 μm, and 12 μm.

[0024] In this embodiment, the addition amount of the nano-TiO2 antibacterial masterbatch is 1-5%, calculated by mass fraction.

[0025] Embodiment 2:

[0026] The present invention also provides a method for preparing a milky white PETG shrink film, wherein the shrink film is placed in corresponding hoppers according to the ratio of the outer layer thickness of 10-12 μm, the middle layer thickness of 30-40 μm, the first adhesive layer and the second adhesive layer thickness of 10-12 μm, and the inner layer thickness of 12-15 μm, wherein the slow-release antibacterial layer of nano-TiO 2The antibacterial masterbatch is added in an amount of 1-5% and mixed evenly with the PETG masterbatch; a blank tube is co-extruded from an extruder in the order of outer layer / first adhesive layer / middle layer / second adhesive layer / inner surface layer, and then the blank tube is subjected to cold air cooling treatment; the cooled blank tube is preheated to 40-90° C. by water vapor, and then the blank tube is transversely stretched and secondarily inflated by compressed air; a film obtained by the second inflating is pulled to a setting machine, and heated to a setting temperature of 50-80° C. to set the film, thereby obtaining a multi-layer co-extruded nano-TiO 2 Finished antibacterial PETG shrink packaging film. The thickness ratio of the outer layer, the first adhesive layer, the middle layer, the second adhesive layer, and the inner surface layer is 10μm, 10μm, 30μm, 10μm, and 12μm.

[0027] The present invention further provides that the slow-release antibacterial layer of nano-TiO 2 The addition amount of antibacterial masterbatch is 2%, 3% and 4% respectively.

[0028] The temperature of each zone of the extruder for the outer layer and the inner layer is 150-165°C, and the temperature of each zone of the extruder for the middle layer, the first bonding layer and the second bonding layer is 160-166°C.

[0029] The cooled tube is preheated to 80°C using steam.

[0030] The film obtained by the secondary inflation is pulled to a setting machine and heated to a setting temperature of 65°C to perform setting treatment on the film.

[0031] Now let’s do the following experiment on the specific effect:

[0032] Experimental Group 1:

[0033] Test group 1 was prepared by the method in Example 2:

[0034] The shrink film is placed in the corresponding hopper according to the ratio of outer layer thickness of 10 μm, middle layer thickness of 30 μm, first adhesive layer and second adhesive layer thickness of 10 μm, inner layer thickness of 12 μm, among which the slow-release antibacterial layer of nano-TiO 2 The antibacterial masterbatch is added in an amount of 2% and mixed evenly with the PETG masterbatch; a blank tube is co-extruded from an extruder in the order of outer layer / first adhesive layer / middle layer / second adhesive layer / inner surface layer, and then the blank tube is subjected to cold air cooling treatment; the cooled blank tube is preheated to 40-90° C. by water vapor, and then the blank tube is transversely stretched and secondarily inflated by compressed air; a film obtained by the second inflating is pulled to a setting machine, and heated to a setting temperature of 50-80° C. to perform a setting treatment on the film, thereby obtaining a multi-layer co-extruded nano-TiO 2 The finished product of the antibacterial PETG shrink packaging film is recorded as sample 1.

[0035] Experimental Group 2:

[0036] Test group 2 was prepared by the method in Example 2:

[0037] The shrink film is placed in the corresponding hopper according to the ratio of outer layer thickness of 10 μm, middle layer thickness of 30 μm, first adhesive layer and second adhesive layer thickness of 10 μm, inner layer thickness of 12 μm, among which the slow-release antibacterial layer of nano-TiO 2 The antibacterial masterbatch is added in an amount of 3% and mixed evenly with the PETG masterbatch; a blank tube is co-extruded from an extruder in the order of outer layer / first adhesive layer / middle layer / second adhesive layer / inner surface layer, and then the blank tube is subjected to cold air cooling treatment; the cooled blank tube is preheated to 40-90° C. by water vapor, and then the blank tube is transversely stretched and secondary inflated by compressed air; a film obtained by the secondary inflating is pulled to a setting machine, heated to a setting temperature of 50-80° C., and the film is subjected to setting treatment to obtain a multi-layer co-extruded nano-TiO 2 The finished product of the antibacterial PETG shrink packaging film is recorded as sample 2.

[0038] Experimental Group 3:

[0039] Test group 3 was prepared by the method in Example 3:

[0040] The shrink film is placed in the corresponding hopper according to the ratio of outer layer thickness of 10 μm, middle layer thickness of 30 μm, first adhesive layer and second adhesive layer thickness of 10 μm, inner layer thickness of 12 μm, among which the slow-release antibacterial layer of nano-TiO 2 The antibacterial masterbatch is added in an amount of 4% and mixed evenly with the PETG masterbatch; a blank tube is co-extruded from an extruder in the order of outer layer / first adhesive layer / middle layer / second adhesive layer / inner surface layer, and then the blank tube is subjected to cold air cooling treatment; the cooled blank tube is preheated to 40-90° C. by water vapor, and then the blank tube is transversely stretched and secondary inflated by compressed air; a film obtained by the secondary inflating is pulled to a setting machine, and heated to a setting temperature of 50-80° C. to perform setting treatment on the film, thereby obtaining a multi-layer co-extruded nano-TiO 2 The finished product of the antibacterial PETG shrink packaging film is recorded as Sample 3.

[0041] Control group:

[0042] The shrink film is placed in the corresponding hopper according to the ratio of outer layer thickness of 10 μm, middle layer thickness of 30 μm, first adhesive layer and second adhesive layer thickness of 10 μm, inner layer thickness of 12 μm, among which the slow-release antibacterial layer of nano-TiO 2The antibacterial masterbatch is added in an amount of 0% and mixed evenly with the PETG masterbatch; a blank tube is co-extruded from an extruder in the order of outer layer / first adhesive layer / middle layer / second adhesive layer / inner surface layer, and then the blank tube is subjected to cold air cooling treatment; the cooled blank tube is preheated to 40-90° C. by water vapor, and then the blank tube is transversely stretched and secondary inflated by compressed air; a film obtained by the secondary inflating is pulled to a setting machine, and heated to a setting temperature of 50-80° C. to perform a setting treatment on the film, thereby obtaining a multi-layer co-extruded nano-TiO 2 The finished product of the antibacterial PETG shrink packaging film is recorded as sample 4.

[0043] The specific values ​​are shown in the following table:

[0044]

[0045]

[0046] The following antibacterial tests were performed on samples 1-4: According to the method of GB / T 21510-2008 "Test Methods for Antibacterial Properties of Nano-inorganic Materials", the antibacterial film was cut into a standard size of (50±2) mm×(50±2) mm. The blank film was used as a covering film, and its size was (40±2) mm×(40±2) mm. Pseudomonas MN10, Carnosus VE51, Lactococcus VE58 and Lactobacillus VMR17 were diluted to an appropriate concentration (about 107 CFU / mL) with sterile saline, 200 μL of bacterial solution was taken on the film with the antibacterial side facing up, and the sterilized covering film was covered on the bacterial solution, and the sample was exposed to light at 30°C for 24 hours. The sample was taken out after 24 hours of culture, and the antibacterial film and the covering film were repeatedly washed with 25 mL of eluent. After the eluate mixture is fully shaken, it is diluted in a gradient manner. Select the appropriate dilution, draw 1 mL into 45°C TSA and MRS culture medium, mix evenly, and after solidification, culture at 30°C for 24 hours, observe the results, and calculate its antibacterial rate. The formula is as follows:

[0047] R = (AB) / A × 100%;

[0048] Where: R is the antibacterial rate / %; A is the average number of bacteria recovered after the control sample has been in contact with the test bacteria for a certain period of time, CFU / mL; B is the average number of bacteria recovered after the test sample has been in contact with the test bacteria for a certain period of time, CFU / mL.

[0049] The addition of TiO2 makes the shrink film of the present invention have antibacterial function. 2 The antibacterial effect of antibacterial heat shrink film on Pseudomonas MN10, Carnosus VE51, Lactococcus VE58 and Lactobacillus VMR17, the experimental data are as follows:

[0050] Pseudomonas MN10 Carnosaurus VE51 Lactococcus VE58 Lactobacillus VMR17 Sample 1 50.23 59.44 46.89 89.32 Sample 2 79.83 96.21 78.22 90.58 Sample 3 95.27 98.22 96.19 99.23 Sample 4 0 0 0 0

[0051] According to the above experimental data, nano-TiO 2 Antibacterial heat shrink film shows good inhibitory effect on fresh meat spoilage bacteria. 2 With the increase of the added amount, nano-TiO 2 The antibacterial effect of the antibacterial heat shrinkable film is enhanced, and the prepared nano-TiO 2 The antibacterial heat shrink film has the function of inhibiting or killing bacteria.

[0052] The present invention adds a certain mass fraction of nano-TiO 2 It can effectively inhibit the growth of dominant spoilage bacteria in fresh meat such as Pseudomonas, Carnobacterium, Lactococcus and Lactobacillus, and with the addition of nano-TiO 2 The antibacterial effect of the heat shrinkable film increases with the increase of the added amount, and it is evenly distributed on the surface of the heat shrinkable film and has no significant effect on the transparency of the film.

[0053] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect.

[0054] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0055] The above description shows and describes several preferred embodiments of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. Changes and variations made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A milky white PETG shrink film, characterized in that: It includes an outer layer, a first bonding layer, an intermediate layer, a second bonding layer and an inner layer. The first bonding layer is used to bond the outer layer and the intermediate layer, and the second bonding layer is used to bond the intermediate layer and the inner layer. The inner layer is a sustained-release antibacterial layer, and the nano-TiO2 antibacterial masterbatch is uniformly mixed with the PETG masterbatch in a certain amount. The outer layer is a PETG layer, the intermediate layer is a PVDC layer, and the first bonding layer and the second bonding layer are EVA layers.

2. A milky white PETG shrink film according to claim 1, characterized in that, The thickness of the outer surface layer is 10-12 μm, the thickness of the middle layer is 30-40 μm, the thickness of the first adhesive layer and the second adhesive layer are both 10-12 μm, and the thickness of the inner surface layer is 12-15 μm.

3. A milky white PETG shrink film according to claim 1, characterized in that: The thicknesses of the outer layer, the first adhesive layer, the middle layer, the second adhesive layer and the inner layer are 10 μm, 10 μm, 30 μm, 10 μm and 12 μm.

4. A milky white PETG shrink film according to claim 1, characterized in that: The added amount of the nano-TiO2 antibacterial masterbatch is 1-5% by mass fraction.

5. A method for preparing a milky white PETG shrink film, characterized in that: The shrink film is placed in corresponding hoppers according to the ratio of outer layer thickness of 10-12 μm, middle layer thickness of 30-40 μm, first adhesive layer and second adhesive layer thickness of 10-12 μm, and inner layer thickness of 12-15 μm, wherein the slow-release antibacterial layer nano-TiO2 antibacterial masterbatch in the inner layer is added in an amount of 1-5% and mixed evenly with the PETG masterbatch; a blank tube is co-extruded from an extruder in the order of outer layer / first adhesive layer / middle layer / second adhesive layer / inner layer, and then the blank tube is subjected to cold air cooling treatment; The cooled blank tube is preheated to a preset temperature with water vapor, stretched transversely, and inflated for a second time with compressed air; the film obtained by the second inflation is pulled to a shaping machine, heated to a shaping temperature, and shaped to obtain a multi-layer co-extruded nano-TiO2 antibacterial PETG shrink packaging film product.

6. The method for preparing a milky white PETG shrink film according to claim 5, characterized in that: The thickness ratio of the outer layer, the first bonding layer, the middle layer, the second bonding layer and the inner surface layer is 10μm, 10μm, 30μm, 10μm and 12μm.

7. The method for preparing a milky white PETG shrink film according to claim 5, characterized in that: The addition amounts of nano-TiO2 antibacterial masterbatch in the sustained-release antibacterial layer in the inner surface layer are 2%, 3% and 4% respectively.

8. The method for preparing a milky white PETG shrink film according to claim 5, characterized in that: The temperature of each zone of the extruder for the outer layer and the inner layer is 150-165°C, and the temperature of each zone of the extruder for the middle layer, the first bonding layer and the second bonding layer is 160-166°C.

9. The method for preparing a milky white PETG shrink film according to claim 5, characterized in that: The cooled tube is preheated to 80°C using steam.

10. The method for preparing a milky white PETG shrink film according to claim 5, characterized in that: The film obtained by the secondary inflation is pulled to a setting machine and heated to a setting temperature of 65°C to perform setting treatment on the film.

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