Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to provide the composite material for the bionic skin, the bionic skin made of the composite material has elasticity close to that of the living skin, and the damage effect of the composite material is close to that of the living skin.
In order to solve the technical problems, the invention provides the following technical scheme:
A composite material for bionic skin comprises an adhesive film layer or/and an adhesive film layer and a structural film layer, wherein two adjacent adhesive film layers are adhered, two adjacent structural film layers are adhered through the adhesive film layer, and the structural film layer is one or more of a polyurethane film layer, a polybutylene carbonate film layer and a silicone rubber film layer.
The bonding film layer is a polyvinyl acetate film layer.
The composite material for bionic skin is prepared by adopting a polyvinyl acetate irradiation method for preparing a polyvinyl acetate film layer.
When the bionic skin comprises more than or equal to 4 layers of film layers, the bonding film layers comprise a first bonding layer and a second bonding layer, the first bonding layer and the second bonding layer are both polyvinyl acetate film layers, and only the first structural film layer and the second structural film layer are connected through the first bonding layer from the surface layer of the bionic skin to the inner layer.
The bionic skin composite material is prepared by adopting polyvinyl acetate used for preparing the second adhesive layer as an irradiation method.
The thickness of the single adhesive film layer of the composite material for the bionic skin is smaller than or equal to that of the single structural film layer.
The thickness of the polyurethane film layer of the bionic skin composite material is 5-120 mu m, the thickness of the polybutylene carbonate film layer is 2-120 mu m, and the thickness of the silicone rubber film layer is 10-300 mu m.
When the structural film layer and the adhesive film layer are prepared into the bionic skin composite material, the assembled bionic skin composite material blank is placed in an incubator for standing and pressing for 60-180 min, and a bionic skin composite material finished product is obtained, wherein the temperature of the incubator is 3-12 ℃, and the pressure applied during standing and pressing is 50-120 Pa.
The bionic skin composite material is subjected to standing and pressure release, and is divided into an initial stage, an intermediate stage and an end stage, wherein the duration of the initial stage is t1, the duration of the intermediate stage is t2, the duration of the end stage is t3, the total duration of the standing and pressure release is t, t is t1＝(3～4):1,t:t2＝(2～3):1,t:t1 = (3-4): 1, the temperature of an incubator at the initial stage is 10-12 ℃, the temperature of the incubator at the intermediate stage is 3-6 ℃, and the temperature of the incubator at the end stage is 6-10 ℃.
According to the bionic skin composite material, the temperature of the incubator at the initial stage is 10-12 ℃, the temperature of the incubator at the middle stage is 3-5 ℃, and the temperature of the incubator at the end stage is 8-10 ℃.
The technical scheme of the invention has the following beneficial technical effects:
1. The invention provides a composite material for bionic skin, which can be used for simulating human skin, can simulate the skin structurally, has physical properties similar to those of real skin, and has the same damage effect evaluation as that of real skin in the damage effect evaluation.
2. The invention adopts a low-temperature static pressure-placing mode to press the adhesive film layer and the structural film layer together, ensures the adhesive force of the adhesive film layer and the structural film layer, can ensure that the adhesive film layer and the structural film layer are not peeled off when being subjected to traction force, and can show similar or identical damage effect when the thickness of the bionic skin is similar to that of the real skin.
Detailed Description
Example 1
As shown in fig. 1, the bionic skin composite material in this embodiment includes an adhesive film layer, and the adhesive film layer is polyvinyl acetate. Wherein the first adhesive film layer 1-1 serves as a horny layer, the second adhesive film layer 1-2 serves as a transparent layer, the third adhesive film layer 1-3 serves as a granular layer, the fourth adhesive film layer 1-4 serves as a ratchet layer, the fifth adhesive film layer 1-5 serves as a basal layer, and the sixth adhesive film layer 1-6 serves as a dermis layer.
When the adhesive film layer is made into the bionic skin composite material, adhesive film layers with the thickness of 5 mu m, 3 mu m, 10 mu m, 17 mu m, 4 mu m and 80 mu m are respectively manufactured, then the adhesive film layers are sequentially stacked from top to bottom to prepare the bionic skin composite material blank, the bionic skin composite material blank is placed between two stainless steel plates for standing and pressing, then the two stainless steel plates and the bionic skin composite material blank are placed into an incubator together, the standing and pressing are carried out for 80min, the temperature of the incubator is 5 ℃, and the unit area weight of the stainless steel plate above the bionic skin composite material blank is 5kg. And after the static pressure is set, the bionic skin composite material can be obtained.
Example 2
As shown in fig. 2, the bionic skin composite material in this embodiment includes an adhesive film layer and a structural film layer, wherein the adhesive film layer is a1 μm thick polyvinyl acetate film layer, the polyvinyl acetate used for preparing the polyvinyl acetate film is prepared by an irradiation method, and the structural film layer includes a2 μm thick polybutylene carbonate film layer, a 4 μm thick polybutylene carbonate film layer, a 3 μm thick silicone rubber film layer, a 17 μm thick polyurethane film layer, a 5 μm thick polybutylene carbonate film layer, and a 80 μm thick polyurethane film layer. The polyvinyl acetate prepared by the irradiation method can lead molecules of a polymer main chain to be connected through chemical bonds, finally forms a three-dimensional network structure, can improve the mechanical strength, toughness (fracture resistance), wear resistance, environmental stress cracking resistance, thermal deformation temperature and the like of materials, simultaneously, the irradiation initiates oxidation reaction, increases polar end groups on a matrix polymer, endows better adhesion force between layers, improves the mechanical strength, interlayer viscosity, ageing resistance and the like of a composite layer film, and improves the quality of composite skin equivalent materials. In FIG. 2, the first structural film layer 2-1 is a polybutylene carbonate film layer 2 μm thick and serves as a stratum corneum, the second structural film layer 2-2 is a polybutylene carbonate film layer 4 μm thick and serves as a transparent layer, the third structural film layer 2-3 is a silicone rubber film layer 3 μm thick and serves as a particle layer, the fourth structural film layer 2-4 is a polyurethane film layer 17 μm thick and serves as a ratchet layer, the fifth structural film layer 2-5 is a polybutylene carbonate film layer 5 μm thick and serves as a basal layer, the sixth structural film layer 2-6 is a polyurethane film layer 80 μm thick and serves as a dermis layer, and the first adhesive layer 2-7 and the second adhesive layer 2-8 provide a connecting force between the different film layers.
The preparation method comprises the steps of sequentially stacking a polybutylene carbonate film layer with the thickness of 2 mu m, a polyvinyl acetate film layer with the thickness of 1 mu m, a polybutylene carbonate film layer with the thickness of 4 mu m, a polyvinyl acetate film layer with the thickness of 1 mu m, a silicone rubber film layer with the thickness of 3 mu m, a polyvinyl acetate film layer with the thickness of 1 mu m, a polyurethane film layer with the thickness of 17 mu m, a polyvinyl acetate film layer with the thickness of 1 mu m, a polybutylene carbonate film layer with the thickness of 5 mu m, a polyvinyl acetate film layer with the thickness of 1 mu m and a polyurethane film layer with the thickness of 80 mu m from top to bottom to prepare a composite material blank for the bionic skin, placing the composite material blank for the bionic skin between two stainless steel plates, placing the two stainless steel plates together with the composite material blank for the bionic skin into a heat preservation box, standing and pressing for 140min, wherein the unit weight of the stainless steel plates above the composite material blank for the bionic skin is 9kg. And after the static pressure is set, the bionic skin composite material can be obtained.
Example 3
The composite material for bionic skin in this embodiment includes an adhesive film layer and a structural film layer, and the bionic skin made of the composite material for bionic skin in this embodiment has the same structure as the bionic skin made in embodiment 2. The adhesive film layer comprises a first adhesive layer and a second adhesive layer, wherein the first adhesive layer and the second adhesive layer are polyvinyl acetate film layers, the preparation method of polyvinyl acetate used for preparing the first adhesive layer comprises the steps of carrying out bulk polymerization on vinyl acetate by taking benzoyl peroxide as an initiator in the presence of acetic acid, preparing the second adhesive layer by taking polyvinyl acetate as an irradiation method, and connecting the bionic skin surface layer to the inner layer through a first adhesive layer only by the first structural layer and the second structural layer. The thicknesses of the first adhesive layer and the second adhesive layer are the same as those of the adhesive film layer in example 2, and the structural film layer in this example is the same as that in example 2.
When the adhesive film layer and the structural film layer in the embodiment are used for preparing the bionic skin, the adhesive film layer between the polybutylene carbonate film layer with the thickness of 2 mu m and the polybutylene carbonate film layer with the thickness of 4 mu m is a first adhesive layer, and the rest adhesive film layers are second adhesive layers.
When bionic skin is prepared in the embodiment, the temperature of the incubator is 12 ℃, and the weight of a stainless steel plate per unit area above the composite material blank for the bionic skin is 12kg.
Example 4
The composition of the bionic skin composite material in this example is the same as that of the bionic skin composite material in example 3, and the following differences exist in preparation method:
Placing the two stainless steel plates together with the composite material blank for the bionic skin into an incubator, preserving heat for 50min at the initial stage, reducing the temperature to 4 ℃ after the heat preservation is finished, continuously preserving heat at the intermediate stage for 80min, and raising the temperature to 9 ℃ after the heat preservation at the intermediate stage is finished, and continuously preserving heat for 50min.
The bionic skin-applied composite materials of example 1, example 2, example 3 and example 4 were compared with the skin of the back of a long white pig, and a tensile test and an indentation test were performed, respectively. Wherein the indentation test is used to characterize elasticity, since the stress-strain relationship corresponds to a single value in each branch of the prescribed cycle, the sample material can be treated as one elastic material during loading and as another elastic material during unloading. The method can be used for testing and processing by means of elastic theory, the elastic mechanics principle adopts the mode that the test piece is loaded and pressed on the surface of the test piece with a specified load, the test piece is unloaded after a specified holding time is passed, the indentation diameter of the surface of the test piece is measured within the specified time, and the elastic performance of the equivalent material is evaluated by the average pressure on the surface area of the indentation of the test piece, so that the equivalent with the skin is realized.
Table 1 results of tensile test of bionic skin composite materials and pigskin in examples 1 to 4
| Selecting materials | Breaking strength (N) | Elongation at break (%) |
| Example 1 | 1914.2 | 44.3 |
| Example 2 | 2156.1 | 48.9 |
| Example 3 | 2113.5 | 47.2 |
| Example 4 | 2178.6 | 49.5 |
| Pigskin | 2017.9 | 46.1 |
When the bionic skin prepared in example 4 was compared with fresh pigskin, it was found that the consistency of the test results of the bionic skin prepared in example 4 and fresh pigskin was not more than 5%.
The piezochromic material is an intelligent material with obviously changed color under the action of external force. The principle of piezochromic material color change is shown in figure 4. The piezochromic material has important potential application prospect in the fields of stress sensing, information storage, commodity anti-counterfeiting, luminescent devices and the like, and has received great attention in recent years. For accurate blunt-impact damage assessment, it is contemplated to apply the piezochromic material to the surface of the skin equivalent material or blend with the skin equivalent material. The piezochromic process under different pressure conditions can be quantitatively characterized, and the material generates color change along with the increase of external force. The structure and the dosage of the piezochromic material are regulated, the quantitative relation between the impact strength and the color is utilized to equivalent the skin injury state under different impact strengths, and the visibility and the evaluation accuracy are improved. When the composite materials for bionic skin in example 1, example 2, example 3 and example 4 were subjected to indentation test with long white pig back skin and fresh pig skin, the six materials produced no difference in color under varying sunlight.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While the obvious variations or modifications which are extended therefrom remain within the scope of the claims of this patent application.