Silk fibroin plastic packaging film, preparation method and application thereof

Abstract

The application discloses a silk fibroin plastic sealing film and a preparation method and application thereof. The film comprises a base layer and an adhesive layer, and the base layer and the adhesive layer are both composed of regenerated silk fibroin, and the adhesive layer further contains inorganic salts of lithium or calcium. The preparation method is as follows: a regenerated silk fibroin film / cocoon silk protein film is prepared on a base as the base layer, a regenerated silk fibroin wet film is scraped on the base layer, drying is carried out to obtain the adhesive layer, and the base layer and the adhesive layer are peeled off from the base together to obtain the silk fibroin plastic sealing film. The film can be bonded by plastic sealing at normal temperature to high temperature, has the characteristics of transparency and air permeability, can be swelled in water, and is suitable for drug packaging and skin electronics.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high polymer materials, and particularly relates to a plastic packaging film made of protein material and a preparation method and application thereof. BACKGROUND

[0002] The interface control between multiple layers of polymers has an important influence on material functions and mechanical properties. Since film materials are often used as the substrate of optoelectronic devices, the interface function optimization of the multi-layer film is a key technology in the field of film packaging.

[0003] Silk fibroin is a natural biological polymer material, which has excellent biocompatibility, degradability and easy processability. However, due to the lack of research on the silk fibroin / silk fibroin interface, most of the research on silk fibroin related film materials is based on the single layer structure of silk fibroin. Only a few researchers have reported the multi-layer manufacturing strategy for silk fibroin film, for example, the research team of Tufts University in the United States realized the hot-press bonding of multi-layer silk fibroin by controlling the crystallinity (DOI: 10.1021 / bm400305r, 2013; DOI: 10.1002 / adfm.201502819, 2015), and the research team of Zhejiang University realized the laminating bonding of multi-layer silk fibroin film by water vapor pretreatment (DOI: 10.1126 / sciadv.abo0946, 2022). Among them, the strategy of controlling the crystallinity cannot overcome the intrinsic brittleness of low crystalline silk fibroin film, and the hot-press control requires high requirements and is difficult to be applied on a large scale; the water vapor pretreatment method requires the film material to be pre-frozen and dried, and its operation process is more complex. Since it has a porous feature, it is opaque after bonding. It should be pointed out that the preparation of silk fibroin film capable of plastic packaging bonding at room temperature to high temperature is still a blank. SUMMARY

[0004] The purpose of the present application is to provide a silk fibroin plastic packaging film material capable of meeting the plastic packaging application and a preparation method and application thereof, so as to utilize the good biocompatibility and degradability of silk fibroin, and the film can be plastic packaged and bonded at room temperature to high temperature, thereby realizing the further application of silk fibroin material in the fields of biological medicine, flexible electronic packaging and the like.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] I. A silk fibroin plastic packaging film:

[0007] The silk fibroin plastic packaging film comprises a substrate layer and an adhesive layer containing inorganic salt, and the substrate layer and the adhesive layer are both composed of regenerated silk fibroin,

[0008] The inorganic salt is lithium or calcium inorganic salt.

[0009] The content of the inorganic salt in the adhesion layer is 5wt%-60wt%.

[0010] The base layer is a regenerated silk fibroin film.

[0011] The silk fibroin plastic packaging film has transparency.

[0012] II. A method for preparing a silk fibroin plastic packaging film:

[0013] 1) preparing a regenerated silk fibroin film / silk fibroin film on a substrate as a base layer;

[0014] 2) scraping a regenerated silk fibroin wet film on the base layer to obtain an adhesion layer after drying;

[0015] 3) peeling the base layer and the adhesion layer together from the substrate to obtain a silk fibroin plastic packaging film.

[0016] The present application is to prepare a silk fibroin plastic packaging film by film coating method.

[0017] The scraped regenerated silk fibroin wet film is specifically prepared by dissolving degummed silk in an inorganic salt-formic acid solution, then placing it in an ultrasonic cleaner for oscillation to obtain a regenerated silk fibroin solution, and coating the regenerated silk fibroin solution on the surface of the silk fibroin film.

[0018] The inorganic salt-formic acid solution is specifically lithium chloride-formic acid solution or calcium chloride-formic acid solution.

[0019] The inorganic salt-formic acid solution is a solution formed by dissolving inorganic salt in formic acid, with a concentration of 0.8wt%-18%.

[0020] The silk fibroin plastic packaging film can be applied in plastic packaging.

[0021] The silk fibroin plastic packaging film can be used for plastic packaging operation at room temperature-200℃.

[0022] Application of the silk fibroin plastic packaging film in plastic packaging

[0023] The two layers of the silk fibroin plastic packaging film are placed opposite to each other, with their respective adhesive layers arranged opposite to each other, and then bonded by a plastic packaging machine at 200℃ to realize the plastic packaging bonding of the two layers of silk fibroin plastic packaging film.

[0024] The regenerated silk fibroin film / silk fibroin film in the present application is a film prepared in patent CN112266490A.

[0025] The mechanism realized by the application is that the crystallization degree and softening temperature of the silk fibroin in the adhesive layer are reduced by using inorganic salt ions, so that the silk fibroin can have adhesion to other silk fibroin materials in a wide temperature range from normal temperature to 200 DEG C, thereby realizing plane plastic packaging and multi-layer bonding effect; at the same time, the application realizes multi-layer bonding in a single material system by regulating the properties and interface characteristics of the silk fibroin composite film, and unexpected technical effects are obtained, which provides a basis for the application of the silk fibroin system in the fields of biological medicine, photoelectric devices and the like.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] (1) The silk fibroin plastic packaging film of the application can completely package functional components such as drug components and electronic circuits in the silk fibroin material, and the wide working range can meet the activity requirements of the drug on the packaging material or the requirements of the flexible optoelectronic device on the packaging temperature.

[0028] (2) The silk fibroin plastic packaging film of the application is not only suitable for traditional double-layer sandwiched plastic packaging applications, but also can meet the requirements of multi-layer plastic packaging bonding in a stacking mode, which is a technical effect brought by the single-component characteristics of the silk fibroin plastic packaging film, and provides a basis for laminating the silk fibroin structural material.

[0029] (3) The backing layer and the adhesive layer of the silk fibroin plastic packaging film of the application have transparent and breathable characteristics, so the silk fibroin plastic packaging film prepared therefrom also has transparent (the light transmittance in the visible light range reaches 90%, and the haze is less than 2%) and breathable characteristics (the water vapor transmittance of the double-layer film plastic packaging is greater than 5*10 4 g·m 2 ·day 1 at 80 DEG C in a heating environment), which is suitable for drug packaging, skin electronics and other application scenarios.

[0030] (4) The main component of the silk fibroin plastic packaging film of the application is a natural polymer material, which has degradable characteristics and is environmentally friendly.

[0031] (5) The preparation method of the silk fibroin plastic packaging film of the application is simple, the production cost is low, the cycle is short, the repeatability is good, and it is suitable for batch preparation. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic view of the cross section of the silk fibroin plastic packaging film;

[0033] Figure 2 is a digital image of the silk fibroin plastic packaging film obtained in Example 2 after double-layer plastic packaging of ordinary paper;

[0034] Figure 3Microscope and digital photo of the single layer and multi-layer bonded silk fibroin plastic packaging film obtained in Example 3.

[0035] Figure 4 UV-visible diffuse reflectance spectrum of the double-layer plastic packaging of the silk fibroin plastic packaging film obtained in Example 3.

[0036] Figure 5 Digital photo of the double-layer film obtained in Example 3 with the sheet-shaped medicine packaged inside.

[0037] Figure 6 Digital photo of the double-layer film obtained in Example 3 with the silk screen printed electrode packaged inside.

[0038] In the figure: base layer (1), adhesive layer (2), inorganic salt (3). DETAILED DESCRIPTION

[0039] The application will be further described below in conjunction with specific examples and drawings.

[0040] Example 1:

[0041] The silk fibroin film prepared by the method described in the preceding patent CN112266490A was used as the base layer 1, and PET was selected as the base carrier for film preparation.

[0042] A lithium chloride-formic acid solution with a concentration of 6wt% was prepared, 0.5g of degummed silk was dissolved in 8.2ml of the above solution, and placed in an ultrasonic cleaner for oscillation for 0.1h to obtain a regenerated silk fibroin solution.

[0043] The regenerated silk fibroin solution was coated on the surface of the silk fibroin film, and dried at room temperature to form the adhesive layer 2. The base layer 1 and the adhesive layer 2 formed a silk fibroin composite film, and the silk fibroin composite film was peeled off from the base to obtain the silk fibroin plastic packaging film.

[0044] The adhesive layers of the two layers of the silk fibroin plastic packaging film were placed opposite to each other, and the plastic packaging bonding of the two layers of the silk fibroin plastic packaging film was realized by a plastic packaging machine at 200℃.

[0045] Example 2:

[0046] The silk fibroin film prepared by the method described in the preceding patent CN112266490A was used as the base layer 1, and PET was selected as the base carrier for film preparation.

[0047] A calcium chloride-formic acid solution with a concentration of 0.8wt% was prepared, 0.5g of degummed silk was dissolved in 8.2ml of the above solution, and placed in an ultrasonic cleaner for oscillation and stirring for 2h to obtain a regenerated silk fibroin solution.

[0048] The regenerated silk fibroin solution is coated on the surface of the silk fibroin film, dried at room temperature to form the adhesion layer 2, and the base layer 1 and the adhesion layer 2 form the silk fibroin composite film, and then the silk fibroin composite film is peeled off from the base to obtain the silk fibroin plastic packaging film.

[0049] The two adhesion layers of the two-layer silk fibroin plastic packaging film are placed opposite to each other, and the plastic packaging bonding of the two-layer silk fibroin plastic packaging film can be realized by a plastic packaging machine at 200 DEG C.

[0050] Example 3:

[0051] The silk fibroin film prepared by the method described in the preceding patent CN112266490A is used as the base layer 1, and PET is selected as the base carrier for film preparation.

[0052] A calcium chloride-formic acid solution with a concentration of 18wt% is prepared, 0.5g of degummed silk is dissolved in 8.2ml of the above solution, and placed in an ultrasonic cleaning machine for oscillation for 0.1h to obtain a regenerated silk fibroin solution.

[0053] The regenerated silk fibroin solution is coated on the surface of the silk fibroin film, dried at room temperature to form the adhesion layer 2, and the base layer 1 and the adhesion layer 2 form the silk fibroin composite film, and then the silk fibroin composite film is peeled off from the base to obtain the silk fibroin plastic packaging film.

[0054] The six-layer silk fibroin plastic packaging film is stacked and placed at room temperature, and the multi-layer bonding of the silk fibroin plastic packaging film can be realized by a plastic packaging machine.

[0055] Figure 1 It is a cross-sectional schematic view of the silk fibroin plastic packaging film. The composite film structure includes a backing layer 1 and an adhesion layer 2, wherein the adhesion layer 2 contains inorganic salt ions 3, and the main components of the backing layer 1 and the adhesion layer 2 are both silk fibroin.

[0056] Figure 2 It is a digital photo of the ordinary paper double-layer plastic packaged by the silk fibroin plastic packaging film obtained in Example 2. In the figure, the paper printed with cocoon patterns is plastic packaged in the interlayer by the silk plastic packaging film.

[0057] Figure 3 It is a single-layer film microscope photo (a), a six-layer film bonding microscope photo (b), and a six-layer bonding digital photo (c) of the silk fibroin plastic packaging film obtained in Example 3. It can be seen that the silk fibroin plastic packaging film described in the application can realize multi-layer composite of more than two layers at 200 DEG C.

[0058] Figure 4 It is the ultraviolet-visible diffuse reflectance spectrum of the silk fibroin plastic packaging film obtained in Example 3 after double-layer plastic packaging. As shown in the figure, the light transmittance of the double-layer plastic packaged silk composite film can reach 90% in the visible light range, and the haze is less than 2%.

[0059] Figure 5 A digital photo of a piece of medicine encapsulated inside the double-layered thin film of the silk fibroin plastic encapsulation film obtained in Example 3 is shown in Figure 3. It can be seen that the silk fibroin plastic encapsulation film of the present application can achieve the encapsulation of a piece of medicine.

[0060] Figure 6 A digital photo of a silk screen printed electrode encapsulated inside the double-layered thin film of the silk fibroin plastic encapsulation film obtained in Example 3 is shown in Figure 4. In the photo, the electrode pattern is directly coated on the surface of the plastic encapsulation film by silk screen printing. It can be seen that the silk fibroin plastic encapsulation film of the present application can achieve the multi-layer bonding and encapsulation of a skin electronic.

Claims

1. A silk fibroin sealing film, characterized in that, The silk fibroin sealing film includes a base layer (1) and an adhesive layer (2) containing inorganic salts (3), both of which are composed of regenerated silk fibroin. The inorganic salt (3) is an inorganic salt of lithium or calcium; The inorganic salt (3) has a content of 5 wt% to 60 wt% in the adhesive layer (2); The base layer (1) is a regenerated silk fibroin membrane; The silk fibroin sealing film is transparent; The preparation method of the silk fibroin plastic sealing film includes: 1) Prepare a regenerated silk fibroin membrane / silk fibroin film as a base layer on the substrate (1). 2) A wet film of regenerated silk fibroin is coated on the base layer (1) and dried to obtain the adhesive layer (2). The process of coating the regenerated silk fibroin wet film involves dissolving degummed silk in an inorganic salt-formic acid solution, then placing it in an ultrasonic cleaner to vibrate and obtain a regenerated silk fibroin solution, and finally coating the regenerated silk fibroin solution onto the surface of the silk fibroin film. 3) Peel the base layer (1) and the adhesive layer (2) together from the substrate to obtain the silk fibroin plastic sealant.

2. The application of the silk fibroin sealing film according to claim 1, characterized in that, The application of the silk fibroin sealing film in sealing.

3. A sealing method applied to the silk fibroin sealing film of claim 1, characterized in that, Two layers of silk fibroin plastic sealant films are placed facing each other, with their respective adhesive layers arranged facing each other. The two layers of silk fibroin plastic sealant films are then sealed and bonded together using a plastic sealant machine at 200°C.

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