Anti-adhesion film and preparation method thereof

Abstract

The embodiment of the invention relates to the technical field of food packaging, and discloses an anti-adhesion film and a preparation method thereof.The anti-adhesion film is prepared from, by weight, 0.2 wt%-13.0 wt% of lubricant, 0.1 wt%-10 wt% of surfactant and the balance polyethylene resin; wherein the surface active agent is a silicone surface active agent; the preparation method of the anti-adhesion film comprises the following steps: uniformly mixing the weighed components of the anti-adhesion film to obtain a mixture; melting and extruding the mixture to form a melt, wherein the melting temperature is 150-220 DEG C; and carrying out blow molding and cooling molding on the melt to prepare the anti-adhesion film. By applying the technical scheme provided by the invention, the anti-adhesion performance of the polyethylene film on the emulsion calcium milk can be improved, so that the preservation safety of the emulsion calcium milk is guaranteed.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of food packaging, and in particular to an anti - adhesion film and a preparation method thereof. Background Art

[0002] As a nutritional drink, milk calcium in emulsion is deeply loved by consumers due to its characteristics such as easy absorption and good taste. To ensure the freshness and nutritional value of milk calcium in emulsion, plastic film packaging can be selected for milk calcium in emulsion. The packaging film has a certain barrier property, which can reduce the pollution of milk calcium in emulsion by external substances, thereby extending the shelf life of milk calcium in emulsion. At present, common packaging films for milk calcium in emulsion mainly include polyethylene film, polypropylene film, polyester film, etc. Among them, polyethylene film has the characteristics of low cost and excellent processing performance, and is widely used in the field of food packaging.

[0003] However, during the packaging and transportation of milk calcium in emulsion, the characteristics of its own components such as a high calcium ion content lead to an easy interaction between milk calcium in emulsion and the surface of the polyethylene film, resulting in an adhesion phenomenon. When milk calcium in emulsion and the polyethylene film adhere, the film may wrinkle or break, affecting the normal storage and sales of milk calcium in emulsion. Summary of the Invention

[0004] To solve the above problems, the first object of the invention of the present application is to provide an anti - adhesion film, which is beneficial to improving the problem of mutual adhesion between milk calcium in emulsion and the surface of the packaging film, and can improve the use safety of the packaging film.

[0005] The second object of the invention of the present application is to provide a preparation method of the anti - adhesion film, which can prepare a packaging film with good anti - adhesion performance and mechanical strength.

[0006] To achieve the above object, the present invention provides the following technical solutions: In the first aspect, an anti - adhesion film of the present invention comprises the following components by weight percentage: 0.2wt% - 13.0wt% of a lubricant, 0.1wt% - 10wt% of a surfactant, and the balance is polyethylene resin; wherein, the surfactant is a silicone surfactant.

[0007] In some implementation manners, the silicone surfactant is any one or more of dimethyl silicone oil, polyether - modified silicone or silicone emulsion.

[0008] In some implementation manners, the HLB value of the silicone surfactant is 4 - 10.

[0009] In some embodiments, it further comprises the following components by weight percentage: 0.1wt% - 8.0wt% of phosphorylated chitosan solution and 0.3wt% - 15wt% of polyvinyl alcohol, wherein the mass concentration of phosphorylated chitosan in the phosphorylated chitosan solution is 1.0% - 20.0%.

[0010] In some embodiments, the viscosity of the phosphorylated chitosan solution is 100 mPa·s - 500 mPa·s.

[0011] In some embodiments, the lubricant is any one or more of calcium stearate or zinc stearate.

[0012] In a second aspect, a method for preparing an anti - adhesion film of the present invention, which is used to prepare the above - mentioned anti - adhesion film, comprises the following steps: mixing the weighed components of the anti - adhesion film evenly to obtain a mixture; melting and extruding the mixture to form a melt, and the melting temperature is 150°C - 220°C; blow - molding and cooling the melt to form an anti - adhesion film.

[0013] In some embodiments, the blow - up ratio of the melt blow - molding is 2.0 - 3.5, and the drawing speed is 10m / min - 30m / min.

[0014] In some embodiments, the cooling temperature of the melt cooling and forming is 10°C - 25°C.

[0015] In some embodiments, the thickness of the anti - adhesion film is 20μm - 50μm.

[0016] Based on the above - mentioned technical solutions, the present invention has the following technical effects: 1. For the anti - adhesion film provided by the present invention, the silicone surfactant migrates to the surface of the polyethylene resin through the wetting agent and is evenly dispersed on the surface of the polyethylene resin to form a uniform and smooth wetting film. When the silicone surfactant adheres to the surface of the polyethylene resin, it can reduce the surface tension of the polyethylene resin, reduce the friction between the polyethylene resin and the milk - calcium emulsion, and the anti - adhesion film has a certain repellency to the milk - calcium emulsion, which can reduce the possibility of adhesion to the milk - calcium emulsion. The synergistic effect of the silicone surfactant and the wetting agent can significantly improve the anti - adhesion performance of the polyethylene resin, and the anti - adhesion film plays a good role in isolating external pollution, which is beneficial to ensuring the food safety of the milk - calcium emulsion during storage and sales.

[0017] 2. The method for preparing the anti - adhesion film provided by the present invention can prepare a polyethylene film with good anti - adhesion performance. At the same time, the lubricant and the silicone surfactant in the anti - adhesion film are evenly attached to the surface of the polyethylene resin, which can improve the tensile strength of the anti - adhesion film. Specific embodiments

[0018] To facilitate the understanding of the present invention, the present invention will be more comprehensively described below in conjunction with specific embodiments. Preferred embodiments of the present invention are given. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0019] Before further describing various embodiments of the compounds / compositions and methods of the present disclosure in more detail by way of exemplary descriptions, examples, and results, it should be understood that the embodiments of the present disclosure are not limited in application to the details of the methods and compositions described below. The descriptions provided herein are for illustrative purposes only and are not to be construed in a limiting sense. The inventive concept of the present disclosure can have other embodiments or can be practiced or implemented in various ways. Therefore, the language used herein is intended to give the broadest scope and meaning; and the embodiments are intended to be exemplary and not exhaustive and are not intended to limit the present disclosure to these specific embodiments. Moreover, it should be understood that the wording and terminology employed herein are for descriptive purposes and should not be considered limiting unless otherwise indicated. Additionally, in the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the present disclosure.

[0020] However, it will be apparent to those of ordinary skill in the art that the embodiments of the present disclosure can be practiced without these specific details. In other instances, features well known to those of ordinary skill in the art have not been described in detail to avoid unnecessary complication of the description. It is intended that all alternatives, substitutions, modifications, and equivalents that are apparent to those of ordinary skill in the art be included within the scope of the present disclosure. According to the present disclosure, all of the compounds / compositions disclosed herein and their preparation methods, applications, and uses can be prepared and implemented without undue experimentation.

[0021] Therefore, although the compounds / compositions and methods of the present disclosure have been described in accordance with specific embodiments, it will be apparent to those skilled in the art that changes can be made to the formulations, compounds or compositions, and / or methods and to the steps or the order of steps of the methods described herein without departing from the spirit and scope of the inventive concept of the present disclosure.

[0022] As used herein, any reference to "an embodiment" or "embodiments" means that a particular element, feature, structure, or property described in connection with that embodiment is included in at least one embodiment. The phrase "in one embodiment" that appears in the specification in multiple places does not necessarily refer to the same embodiment.

[0023] Unless otherwise defined herein, scientific and technical terms used in connection with this disclosure shall have the meanings commonly understood by those of ordinary skill in the art. In addition, unless the context requires otherwise, singular terms shall include the plural and plural terms shall include the singular.

[0024] The following further details this application.

[0025] An anti - sticking film of the present invention comprises the following components by percentage: 0.2wt% - 13.0wt% of lubricant, 0.1wt% - 10wt% of surfactant, and the balance is polyethylene resin; wherein, the surfactant is a silicone surfactant. Specifically, the polyethylene resin can be food - grade low - density polyethylene resin or linear low - density resin, the density of the polyethylene resin can be 0.918 - 0.935 g / cm³, and the melt flow rate can be 2 - 10 g / 10min.

[0026] In the preparation process, the wetting agent, silicone surfactant and polyethylene resin are mixed evenly. The wetting agent and silicone surfactant migrate to the surface of the polyethylene resin and form a uniform and smooth wetting film. The silicone surfactant reduces the surface tension of the polyethylene resin, and an anti - sticking layer is formed on the surface of the polyethylene resin, which can reduce the surface friction. When the anti - sticking film is used for the packaging of emulsion calcium milk, the synergistic effect of the wetting agent and silicone surfactant can improve the anti - sticking performance of the polyethylene resin, that is, the adhesion force between the anti - sticking film and the emulsion calcium milk is reduced. The anti - sticking film isolates external pollution and can ensure the safety of the emulsion calcium milk during storage and transportation. At the same time, there is a repulsive force between the anti - sticking film and the emulsion calcium milk. The anti - sticking film can maintain flatness during use to reduce the occurrence of wrinkles or breakage, and the anti - sticking film is easy to tear, facilitating consumers to consume the emulsion calcium milk.

[0027] In a preferred embodiment, the silicone surfactant is any one or more of dimethyl silicone oil, polyether - modified silicone or silicone emulsion, such as a single polyether - modified silicone, a composition of dimethyl silicone oil and polyether - modified silicone, etc. Specifically, the HLB value of the silicone surfactant is 4 - 10, such as the HLB value is specifically 4, 6, 7, 8 or 10, etc., which is beneficial to cooperate with the lubricant to reduce the surface tension of the polyethylene resin.

[0028] In a preferred embodiment, the lubricant is any one or more of calcium stearate or zinc stearate. Specifically, the particle size of calcium stearate or zinc stearate is 5μm - 20μm, which is beneficial to the uniform dispersion of the lubricant in the polyethylene resin.

[0029] In a preferred embodiment, the anti - adhesion film of the present invention further comprises the following components by weight percentage: 0.1wt% - 8.0wt% of phosphorylated chitosan solution and 0.3wt% - 15wt% of polyvinyl alcohol, wherein the mass concentration of phosphorylated chitosan in the phosphorylated chitosan solution is 1.0% - 20.0%. Specifically, the phosphorylated chitosan solution preferably but not limited to uses deionized water as the solvent, and the mass concentration of phosphorylated chitosan is 1.0%, 10%, 14%, 18% or 20%, etc., and the degree of phosphorylation (DP) of phosphorylated chitosan is 5% - 30%.

[0030] When high - fat emulsion calcium milk is packaged with the anti - adhesion film, there is a problem that the emulsion calcium milk is prone to rancidity and deterioration after being stored for a long time. The reason may be that silicone surfactants and wetting agents reduce the surface tension of the polyethylene resin by changing the microscopic structure of the polyethylene resin surface, such as increasing the pores. However, with the change of the microscopic structure of the anti - adhesion film and the relatively loose arrangement of molecules in the polyethylene resin, the ability of the anti - adhesion film to block ultraviolet rays weakens, and the emulsion calcium milk is prone to decomposition and deterioration of nutrients under the action of ultraviolet rays. By adding phosphorylated chitosan solution and polyvinyl alcohol, the anti - adhesion film can evenly fill the pores inside the polyethylene resin and inside the wetting film formed by silicone surfactants and wetting agents, thereby improving the microscopic structure of the anti - adhesion film and enhancing the ability to block ultraviolet rays.

[0031] In some specific embodiments, the viscosity of the phosphorylated chitosan solution is 100 mPa·s - 500 mPa·s, such as 100 mPa·s, 300 mPa·s, 460 mPa·s or 500 mPa·s. Phosphorylated chitosan has a better binding force with polyethylene resin, silicone surfactant, wetting agent and polyvinyl alcohol, which is beneficial to improving the microscopic structure of the anti - adhesion film. Specifically, the molecular weight of polyvinyl alcohol can be 50000 - 80000, and the degree of alcoholysis of polyvinyl alcohol can be 88%, which is beneficial to ensuring good fluidity while improving the mechanical strength of the anti - adhesion film.

[0032] A method for preparing an anti - adhesion film of the present invention, which is used to prepare the above - mentioned anti - adhesion film, comprises the following steps: Mix the components of the anti - sticking film weighed evenly to obtain a mixture. In some specific embodiments, the lubricant, silicone surfactant and polyethylene resin can be mixed by a mixer at a rotation speed of 800 - 1000 r / min and a mixing time of 8 - 10 min; The mixture is melt - extruded to form a melt, and the melting temperature is 150℃ - 220℃. Specifically, the mixture can be melt - extruded by a screw extruder, and the rotation speed of the screw extruder is 20 - 50 r / min; Melt blow and cool to form an anti-blocking film. In a preferred embodiment, the blow-up ratio of melt blowing is 2.0 to 3.5, and the draw speed is 10 m / min to 30 m / min. Through low-temperature extrusion and a high blow-up ratio, the anti-blocking film can improve the tensile strength of the anti-blocking film while ensuring its anti-blocking performance. Specifically, the cooling temperature for melt cooling and forming is 10°C to 25°C. With an appropriate cooling temperature, the flatness and transparency of the anti-blocking film can be guaranteed, and the problems of wrinkles or breakage that are prone to occur in the film can be improved.

[0033] In a preferred embodiment, the thickness of the anti-blocking film is 20 μm to 50 μm, such as 20 μm, 30 μm, 42 μm, or 50 μm, etc., which is beneficial to enhancing the mechanical strength of the anti-blocking film.

[0034] Example 1 An anti-blocking film comprises the following components by weight percentage: 0.2 wt% of calcium stearate, 10 wt% of dimethyl silicone oil, and the balance is polyethylene resin. Among them, the polyethylene resin is a food-grade low-density resin, the density of the polyethylene resin is 0.925 g / cm³, and the melt flow rate is 5 g / 10 min. At the same time, the HLB value of dimethyl silicone oil is 6, and the particle size of calcium stearate can be 10 μm.

[0035] The preparation method of the above anti-blocking film comprises the following steps: Mix calcium stearate, dimethyl silicone oil, and polyethylene resin evenly through a mixer. The mixing speed is 800 r / min, and the mixing time is 10 min to obtain a mixture. The mixture is melt-extruded through a screw extruder to form a melt. The melting temperature is 150°C, and the speed is 50 r / min. Melt blow and cool to form. Among them, the blow-up ratio of the melt is 2.0, the winding and draw speed is 30 m / min, the melt can be cooled by air, and the cooling temperature is 10°C to obtain an anti-blocking film. The thickness of the anti-blocking film is 20 μm.

[0036] Example 2 An anti-blocking film comprises the following components by weight percentage: 13.0 wt% of calcium stearate, 0.1 wt% of polyether-modified silicone oil, and the balance is polyethylene resin. Among them, the polyethylene resin is a linear low-density polyethylene resin, the density of the polyethylene resin is 0.918 g / cm³, and the melt flow rate is 8 g / 10 min. At the same time, the HLB value of polyether-modified silicone oil is 4, the ratio of hydrogen-containing silicone oil to polyether in polyether-modified silicone oil can be 1:2, and the particle size of calcium stearate can be 5 μm.

[0037] The preparation method of the above anti-blocking film comprises the following steps: Mix calcium stearate, polyether-modified silicone and polyethylene resin evenly through a mixer. The mixing speed is 1000 r / min and the mixing time is 8 min to obtain a mixture; The mixture is melt-extruded through a screw extruder to form a melt. The melting temperature is 220 °C and the speed is 20 r / min; The melt is blown and cooled into shape. Among them, the blow-up ratio of the melt is 3.5, the winding and traction speed is 10 m / min, the melt can be air-cooled and the cooling temperature is 25 °C to obtain an anti-sticking film. The thickness of the anti-sticking film is 20 μm.

[0038] Example 3 An anti-sticking film includes the following components by weight percentage: 0.38 wt% of zinc stearate, 0.16 wt% of silicone emulsion, and the balance is polyethylene resin. Among them, the polyethylene resin is linear low-density polyethylene resin, the density of the polyethylene resin is 0.918 g / cm³, the melt flow rate is 8 g / 10 min. At the same time, the HLB value of the polyether-modified silicone is 6, and the particle size of calcium stearate can be 11 μm.

[0039] The preparation method of the above anti-sticking film includes the following steps: Mix calcium stearate, polyether-modified silicone and polyethylene resin evenly through a mixer. The mixing speed is 950 r / min and the mixing time is 8 min to obtain a mixture; The mixture is melt-extruded through a screw extruder to form a melt. The melting temperature is 210 °C and the speed is 28 r / min; The melt is blown and cooled into shape. Among them, the blow-up ratio of the melt is 3.2, the winding and traction speed is 18 m / min, the melt can be water-cooled and the cooling temperature is 22 °C to obtain an anti-sticking film. The thickness of the anti-sticking film is 20 μm.

[0040] Example 4 The difference between Example 4 and Example 3 is that the anti-sticking film of this example includes the following components by weight percentage: 0.38 wt% of zinc stearate, 0.16 wt% of silicone emulsion, 8.0 wt% of phosphorylated chitosan solution, 15 wt% of polyvinyl alcohol, and the balance is polyethylene resin. Among them, the mass concentration of phosphorylated chitosan in the phosphorylated chitosan solution is 1.0%, and the viscosity of the phosphochitosan solution is 500 mPa·s.

[0041] Example 5 Example 5 is different from Example 3 in that the anti - sticking film of this example comprises the following components by weight percentage: 0.38 wt% of zinc stearate, 0.16 wt% of silicone emulsion, 0.1 wt% of phosphorylated chitosan solution, 0.3 wt% of polyvinyl alcohol, and the balance is polyethylene resin. Among them, the mass concentration of phosphorylated chitosan in the phosphorylated chitosan solution is 20.0%, and the viscosity of the phosphochitosan solution is 100 mPa·s.

[0042] Comparative Example 1 Comparative Example 1 is different from Example 3 in that fatty acid glyceride of equal mass is used to replace the silicone surfactant in the anti - sticking film.

[0043] Comparative Example 2 Comparative Example 2 is different from Example 3 in that no wetting agent is added to the anti - sticking film, and the anti - sticking film comprises 0.5 wt% of silicone emulsion and the balance is polyethylene resin.

[0044] Comparative Example 3 Comparative Example 3 is different from Example 4 in that an equal amount of chitosan solution is used to replace the phosphorylated chitosan solution in the anti - sticking film, and the mass concentration of chitosan in the chitosan solution is 1%.

[0045] Comparative Example 4 Comparative Example 4 is different from Example 4 in that an equal amount of polyvinylpyrrolidone is used to replace polyvinyl alcohol in the anti - sticking film.

[0046] Comparative Example 5 Comparative Example 5 uses a polyethylene film with a thickness of 20 μm.

[0047] Comparative Example 6 Compared with Example 3, in the preparation method of the anti - sticking film in Comparative Example 6, the melting temperature of the mixture is 260 °C, and the blow - up ratio of melt blow molding is 1.5.

[0048] Performance Test Adhesion Test: The anti - sticking films prepared in Examples 1 - 5 and Comparative Examples 1 - 6 were subjected to an adhesion test. The prepared anti - sticking films were cut into specimens with dimensions of 80 mm×200 mm, and then emulsion calcium milk was applied to the surface of the anti - sticking film specimens. After standing, the adhesion between the anti - sticking film and the emulsion calcium milk was observed.

[0049] Friction Test: According to GB / T 10006 - 2021, the coefficient of friction of the anti - sticking films prepared in Examples 1 - 5 and Comparative Examples 1 - 6 was measured to detect the coefficient of friction between the anti - sticking film and the slider to reflect the anti - sticking performance of the surface of the anti - sticking film.

[0050] Light transmittance test: The anti-adhesion films prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to light transmittance test according to ASTM D1003.

[0051] Ultraviolet test: The anti-adhesion films prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to anti-ultraviolet performance test, and the shielding rate of the anti-adhesion films against 280 nm ultraviolet rays was tested by an ultraviolet tester.

[0052] Mechanical property test: The tensile strength and elongation at break of the anti-adhesion films prepared in Examples 1-5 and Comparative Examples 1-6 were tested according to GB / T 1040.3.

[0053] Test results

[0054] Table 1 Performance test results of the anti-adhesion films prepared in Examples 1-5 and Comparative Examples 1-6 According to the performance test results of Examples 1-5, Comparative Example 1, Comparative Example 2 and Comparative Example 5, it can be seen that there is no adhesion when the anti-adhesion film of the present application comes into contact with milk calcium emulsion, and the friction coefficient is relatively low, which is beneficial to improving the anti-adhesion performance of the anti-adhesion film. At the same time, the anti-adhesion film has a high light transmittance and good mechanical properties. There is a synergistic effect between the silicone surfactant and the wetting agent in the anti-adhesion film. The silicone surfactant migrates to the surface of the polyethylene resin through the wetting agent and is uniformly dispersed on the surface of the polyethylene resin to form a uniform and smooth wetting film. When the silicone surfactant adheres to the surface of the polyethylene resin, the surface tension of the polyethylene resin can be reduced, and the frictional force between the polyethylene resin and the milk calcium emulsion is reduced, making it difficult for the milk calcium emulsion to adhere to the surface of the polyethylene resin.

[0055] According to the performance test results of Examples 1-5, Comparative Example 3 and Comparative Example 4, it can be seen that the higher the ultraviolet shielding rate, the stronger the ultraviolet barrier ability of the anti-adhesion film. The anti-adhesion film can improve the ability to block ultraviolet rays by adding phosphorylated chitosan and polyvinyl alcohol, thereby ensuring the long-term preservation of milk calcium emulsion. Phosphorylated chitosan and polyvinyl alcohol can be uniformly filled into the pores inside the polyethylene resin and inside the wetting film formed by the silicone surfactant and the wetting agent to improve the internal microstructure of the anti-adhesion film, so that a relatively dense structure is formed inside the anti-adhesion film, thereby improving the ability of the anti-adhesion film to block ultraviolet rays.

[0056] According to the performance test results of Examples 1-5 and Comparative Example 6, it can be seen that the anti-adhesion film can improve the tensile strength of the anti-adhesion film while ensuring the anti-adhesion performance of the anti-adhesion film through low-temperature extrusion and high blow-up ratio.

[0057] The above content is only an example and explanation of the structure of the present invention. Its description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these obvious alternative forms all fall within the protection scope of the present invention.

Claims

1. An anti-adhesion film, characterized in that, It comprises the following components by weight percentage: 0.2 wt% - 13.0 wt% of a lubricant, 0.1 wt% - 10 wt% of a surfactant, and the balance is a polyethylene resin; wherein, the surfactant is a silicone surfactant.

2. The anti-adhesion film according to claim 1, characterized in that, The silicone surfactant is any one or more of dimethyl silicone oil, polyether-modified silicone, or silicone emulsion.

3. The anti-adhesion film according to claim 1 or 2, characterized in that, The HLB value of the silicone surfactant is 4 - 10.

4. The anti-adhesion film according to claim 1, wherein It further comprises the following components by weight percentage: 0.1 wt% - 8.0 wt% of a phosphorylated chitosan solution and 0.3 wt% - 15 wt% of polyvinyl alcohol, wherein, the mass concentration of phosphorylated chitosan in the phosphorylated chitosan solution is 1.0% - 20.0%.

5. The anti-adhesion film according to claim 4, characterized in that, The viscosity of the phosphorylated chitosan solution is 100 mPa·s - 500 mPa·s.

6. The anti-adhesion film according to claim 1, wherein The lubricant is any one or more of calcium stearate or zinc stearate.

7. A method for preparing an anti-sticking film, which is used to prepare the anti-sticking film according to any one of claims 1-6, characterized in that, It includes the following steps: Mix the weighed components of the anti-blocking film evenly to obtain a mixture; Melt-extrude the mixture to form a melt, and the melting temperature is 150°C - 220°C; Blow-mold and cool the melt to form an anti-blocking film.

8. The preparation method of the anti-adhesion film according to claim 7, characterized in that, The blow-up ratio of the melt blow molding is 2.0 - 3.5, and the drawing speed is 10 m / min - 30 m / min.

9. The method for preparing the anti-adhesion film according to claim 8, wherein The cooling temperature of the melt cooling and forming is 10°C - 25°C.

10. The preparation method of the anti-adhesion film according to claim 7, wherein The thickness of the anti-blocking film is 20 μm - 50 μm.

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