Ultrathin foldable flexible composite material and preparation method thereof

Abstract

The invention provides an ultrathin foldable flexible composite material and a preparation method thereof. The flexible composite material comprises a matrix, the matrix is derived from a biomass material, and the matrix is obtained by carrying out chemical treatment on the biomass material; the elastomer material is wrapped on the surface of the base body to form a film-shaped protective layer; and at least part of the elastomer material permeates into the gaps and / or pores of the matrix. The ultrathin foldable flexible composite material disclosed by the invention has good flexibility and foldability, so that the ultrathin foldable flexible composite material can replace plastic to be applied to the field of packaging. The preparation method of the ultrathin foldable flexible composite material is simple and easy to implement, raw materials are easy to obtain, and efficient softening and functionalization of the biomass material are achieved through a softening treatment process.

Description

Technical Field

[0001] The invention relates to an ultra-thin foldable flexible composite material and a preparation method thereof, and belongs to the field of biomass materials. Background Art

[0002] With the increasing awareness of environmental protection, finding renewable and degradable materials to replace traditional plastic materials has become a research hotspot. Bamboo, as a plant with abundant resources, high strength, good toughness and renewable nature, has excellent mechanical properties and environmental protection characteristics, and is an ideal alternative material. Bamboo has been widely used in construction, furniture, interior decoration and other fields.

[0003] However, due to its own rigidity and hardness limitations, the potential of traditional bamboo in flexible material applications has not been fully developed, and it is difficult to meet the needs of some specific uses, such as high flexibility and foldability. By properly modifying and compounding bamboo, ultra-thin flexible composite materials with excellent flexibility and foldability can be developed, which can replace plastics in the future.

[0004] Existing bamboo processing methods are mostly focused on enhancing the strength and durability of bamboo, and lack research on the flexible processing of bamboo, resulting in greater limitations in the flexible applications of bamboo. Specifically, there are the following defects, for example: 1. Insufficient flexibility: Traditional bamboo is difficult to achieve high flexibility and foldability due to the high rigidity of the fiber structure. 2. Poor processing performance: Bamboo is prone to cracking and deformation during processing, and it is difficult to prepare uniform, ultra-thin materials. 3. Single function: The functionality of existing bamboo is relatively single, and it is difficult to meet the needs of various application scenarios, such as waterproofing. Summary of the invention

[0005] Problem that the invention aims to solve

[0006] In view of the technical problems existing in the prior art, such as insufficient flexibility, poor processing performance, single function, etc., the present invention first provides an ultra-thin foldable flexible composite material. The ultra-thin foldable flexible composite material of the present invention has good flexibility and foldability, so it can replace plastics in the packaging field.

[0007] Furthermore, the present invention also provides a method for preparing an ultra-thin foldable flexible composite material. The preparation method is simple and easy to implement, and the raw materials are easy to obtain. Through the softening treatment process, efficient softening and functionalization of bamboo can be achieved.

[0008] Solutions for solving problems

[0009] The present invention provides a flexible composite material, comprising:

[0010] A substrate, the substrate being derived from a biomass material, the substrate being obtained by chemically treating the biomass material; and

[0011] an elastomeric material, wherein the elastomeric material is wrapped on the surface of the substrate to form a film-like protective layer; and

[0012] At least a portion of the elastomeric material penetrates into the interstices and / or pores of the matrix.

[0013] According to the flexible composite material of the present invention, the biomass material includes a wood material or a bamboo material; and / or,

[0014] The thickness of the biomass material is 0.1-0.6 mm, preferably 0.15-0.25 mm.

[0015] According to the flexible composite material of the present invention, the chemical treatment comprises chemically treating the biomass material with an alkaline substance and / or an oxide.

[0016] According to the flexible composite material of the present invention, the elastomeric material comprises waterborne polyurethane.

[0017] The present invention also provides a method for preparing the flexible composite material according to the present invention, wherein the preparation method includes the steps of wrapping an elastomeric material on the surface of a substrate to form a film-like protective layer, and allowing at least a portion of the elastomeric material to penetrate into the gaps and / or pores of the substrate.

[0018] According to the preparation method of the present invention, the preparation method comprises the following steps:

[0019] Chemically treating the biomass material with alkaline substances and / or oxides to obtain a matrix;

[0020] Obtaining an elastomer solution, wrapping the elastomer solution on the surface of the substrate to form a film-like protective layer, and allowing at least a portion of the elastomer solution to penetrate into the pores of the substrate to obtain a molded body;

[0021] The molded body is subjected to a pressurizing and curing treatment to obtain a flexible composite material.

[0022] According to the preparation method of the present invention, the alkaline substance includes one or a combination of two or more of KOH, NaOH, Na2SO3, K2SO3, Na2CO3, K2CO3; the oxide includes one or a combination of two or more of H2O2, NaClO2, NaClO;

[0023] Preferably, the chemical treatment time is 1s-120h.

[0024] According to the preparation method of the present invention, the solid content of the elastomer solution is 28-34%; and / or,

[0025] The elastomer solution is wrapped on the surface of the substrate to form a film-like protective layer by one or a combination of two or more of paving, coating, casting and spraying, and at least a portion of the elastomer solution is infiltrated into the pores of the substrate.

[0026] According to the preparation method of the present invention, the temperature of the pressurized curing is 60-90° C., the time of the pressurized curing is 5-10 minutes, and the pressure of the pressurized curing is 1-4 MPa.

[0027] The present invention also provides a use of the flexible composite material according to the present invention for preparing packaging materials.

[0028] Effects of the Invention

[0029] The ultra-thin foldable flexible composite material of the invention has good flexibility and foldability, and can be used in the packaging field instead of plastic.

[0030] The preparation method of the ultra-thin foldable flexible composite material of the present invention is simple and easy, the raw materials are easy to obtain, and the efficient softening and functionalization of the biomass material can be achieved through the softening treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The surface morphologies and cross-sectional morphologies of the ultrathin foldable flexible composite materials of Examples 1-3 of the present invention and the traditional composite material of Comparative Example 1 are shown. DETAILED DESCRIPTION

[0032] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0033] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0034] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0035] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0036] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0037] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0038] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0039] <First aspect>

[0040] A first aspect of the present invention provides a flexible composite material comprising:

[0041] A substrate, the substrate being derived from a biomass material, the substrate being obtained by chemically treating the biomass material; and

[0042] an elastomeric material, wherein the elastomeric material is wrapped on the surface of the substrate to form a film-like protective layer; and

[0043] At least a portion of the elastomeric material penetrates into the interstices and / or pores of the matrix.

[0044] The ultra-thin foldable flexible composite material of the invention has good flexibility and foldability, and can be used in the packaging field instead of plastic.

[0045] Matrix

[0046] The matrix is ​​derived from biomass material, and the matrix is ​​obtained by chemically treating the biomass material. Specifically, in the present invention, the biomass material is derived from wood material or bamboo material, and preferably, the biomass material is derived from bamboo skin (thin bamboo) or wood skin (thin wood).

[0047] Bamboo veneer includes common natural and carbonized side-pressed sliced ​​bamboo veneer, rotary cut bamboo veneer, sliced ​​reconstructed bamboo veneer, flat-pressed sliced ​​bamboo veneer or other bamboo veneer prepared from bamboo integrated materials as sliced ​​raw materials. The rotary cut bamboo veneer is a bamboo veneer material prepared from bamboo as raw material through rotary cutting technology. The sliced ​​reconstructed bamboo veneer is a reconstructed bamboo veneer material prepared from reconstructed bamboo as raw material through softening sliced ​​technology. The wood veneer may include sliced ​​reconstructed veneer, sliced ​​veneer or rotary cut veneer. The sliced ​​reconstructed veneer is a reconstructed veneer material prepared from reconstructed wood as raw material through softening sliced ​​technology. The sliced ​​veneer is a veneer material prepared from the wood part obtained from trees through softening sliced ​​technology. The rotary cut veneer is a veneer material prepared from rotary cutting technology.

[0048] In some specific embodiments, the thickness of the substrate is 0.1-0.6 mm, preferably 0.15-0.25 mm, for example: 0.12 mm, 0.16 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, etc.

[0049] In addition, at least one side of the substrate of the present invention also has a backing layer, so as to further fix and support the substrate. Specifically, the backing layer can be a non-woven fabric.

[0050] In some specific embodiments, the chemical treatment of the present invention includes chemically treating the biomass material with an alkaline substance and / or an oxide. The inventors of the present invention have found that by using chemical treatment, some hard lignin components in the matrix are removed, the rigid cellulose components are softened, and a large number of micro-nano sized pores are formed in the cell structure, and the cellulose of the bamboo material is further softened, thereby reducing the overall rigidity of the material.

[0051] Elastomer materials

[0052] The elastomeric material of the present invention is wrapped around the surface of the substrate to form a film-like protective layer; and at least part of the elastomeric material penetrates into the gaps and / or pores of the substrate. By allowing the elastomeric material to penetrate into the gaps and / or pores of the substrate, the flexibility of the biomass material can be fully increased.

[0053] The inventors of the present invention have found that the elastomer material with good compatibility and good elasticity can fill and wrap the gaps and pore structures of the biomass material in multiple scales, thereby improving the flexibility of the biomass material. In addition, through the hot pressing composite method, the elastomer material and the biomass material cells can be fused with each other, that is, the elastic material is filled into the gaps and pore structures, so that the two are distributed more evenly and have better adhesion.

[0054] Specifically, in the present invention, the elastomeric material includes but is not limited to elastomeric resin materials such as waterborne polyurethane, and is preferably waterborne polyurethane.

[0055] In some specific embodiments, the pores of the backing layer are also infiltrated with an elastomeric material. By infiltrating the pores of the backing layer with an elastomeric material, the stress dispersion of the flexible composite material can be further improved.

[0056] <Second Aspect>

[0057] The second aspect of the present invention provides a method for preparing the flexible composite material according to the first aspect of the present invention, the preparation method comprising the steps of wrapping an elastomeric material on the surface of the substrate to form a film-like protective layer, and allowing at least a portion of the elastomeric material to penetrate into the gaps and / or pores of the substrate.

[0058] The preparation method of the ultra-thin foldable flexible composite material of the present invention is simple and easy, the raw materials are easy to obtain, and the efficient softening and functionalization of the biomass material can be achieved through the softening treatment process.

[0059] In some specific embodiments, the preparation method comprises the following steps:

[0060] Chemically treating the biomass material with alkaline substances and / or oxides to obtain a matrix;

[0061] Obtaining an elastomer solution, wrapping the elastomer solution on the surface of the substrate to form a film-like protective layer, and allowing at least a portion of the elastomer solution to penetrate into the pores of the substrate to obtain a molded body;

[0062] The molded body is subjected to a pressurizing and curing treatment to obtain a flexible composite material.

[0063] Chemical treatment

[0064] Before chemical treatment, a backing layer can be provided on one side of the biomass material, so as to further fix and support the substrate. Specifically, the backing layer can be a non-woven fabric.

[0065] Furthermore, the backing layer can be assembled on one side of the biomass material and then chemically treated. Specifically, the backing layer can be assembled on one side of the biomass material using an adhesive. The amount of the adhesive is not particularly limited in the present invention and can be selected as needed.

[0066] Furthermore, after the backing layer is assembled on one side of the biomass material, hot pressing can be performed to tightly combine the backing layer and the biomass material into one. Specifically, the hot pressing temperature can be 70-90°C, for example: 75°C, 80°C, 85°C, etc.; the hot pressing time can be 80-120 seconds, for example: 90 seconds, 100 seconds, 110 seconds, 120 seconds, etc.

[0067] The present invention does not specifically limit the adhesive, as long as the backing layer can be assembled on one side of the substrate, such as one or a combination of two or more of soybean protein adhesive, urea-formaldehyde resin or polyvinyl acetate emulsion mixed adhesive.

[0068] The present invention first uses alkaline substances and / or oxides to chemically treat biomass materials to obtain a matrix; in the present invention, the time of the chemical treatment is preferably 1s-120h. Specifically, the present invention first uses oxides and then uses alkaline substances to chemically treat biomass materials in sequence to obtain a matrix. Alternatively, the present invention first uses alkaline substances and then uses oxides to chemically treat biomass materials in sequence to obtain a matrix.

[0069] In some specific embodiments, when the biomass material is chemically treated with an oxide, the chemical treatment time is 5h-120h, for example: 10h, 20h, 30h, 50h, 70h, 90h, 100h, 110h, etc., by using the oxide to chemically treat the biomass material, part of the lignin component in the substrate can be removed. When the biomass material is chemically treated with an alkaline substance, the chemical treatment time is 1s to 10min, for example: 10s, 30s, 50s, 1min, 3min, 5min, 7min, 9min, etc. By using an alkaline substance to chemically treat the biomass material, the rigid cellulose component can be softened.

[0070] Further, when using oxides for preparation, an oxide solution can be prepared for chemical treatment. In the oxide solution, the mass fraction of the oxide is 0.5-5%, for example: 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, etc. When using alkaline substances for preparation, an alkaline substance solution can be prepared for chemical treatment. In the alkaline substance solution, the mass fraction of the alkaline substance can be 10-30%, for example: 12%, 15%, 18%, 20%, 22%, 25%, 28%, etc.

[0071] Specifically, in the present invention, the alkaline substance includes one or a combination of two or more of KOH, NaOH, Na2SO3, K2SO3, Na2CO3, K2CO3; the oxide includes one or a combination of two or more of H2O2, NaClO2, NaClO.

[0072] Encapsulation and penetration

[0073] An elastomer solution is obtained, and the elastomer solution is wrapped on the surface of the substrate to form a film-like protective layer, and at least a portion of the elastomer solution is allowed to penetrate into the gaps and / or pores of the substrate, thereby obtaining a molded body.

[0074] Furthermore, the solid content of the elastomer solution is 28-34%, for example: 29%, 30%, 31%, 32%, 33%, etc. The elastomer solution is wrapped on the surface of the substrate to form a film-like protective layer by one or a combination of two or more of paving, coating, casting or spraying, and at least part of the elastomer solution penetrates into the gaps and / or pores of the substrate, preferably by spraying.

[0075] The present invention does not specifically limit the amount of the elastomer solution, and can be set as needed, as long as the function of the present invention can be achieved. Specifically, the amount of the elastomer solution used each time can be 70-100 g / m 2 , for example: 75g / m 2 , 80g / m 2 , 85g / m 2 , 90g / m 2 , 95g / m 2 wait.

[0076] The present invention does not impose any particular limitation on the number of spraying times, which can generally be 1 to 5 times.

[0077] Pressurized curing

[0078] The present invention obtains a flexible composite material by subjecting the molded body to a pressurized curing treatment. The pressurized curing treatment allows the elastomer solution to wrap around the surface of the substrate to form a film-like protective layer, and allows at least part of the elastomer solution to penetrate into the gaps and / or pores of the substrate.

[0079] In some specific embodiments, the temperature of the pressurized curing is 60-90°C, for example: 65°C, 70°C, 75°C, 80°C, 85°C, etc.; the time of the pressurized curing is 5-10 minutes, for example: 5.5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 7.5 minutes, 8 minutes, 8.5 minutes, 9 minutes, 9.5 minutes, etc.; the pressure of the pressurized curing is 1-4MPa, for example: 1.2MPa, 1.5MPa, 1.8MPa, 2MPa, 2.2MPa, 2.5MPa, 2.8MPa, 3MPa, 3.2MPa, 3.5MPa, 3.8MPa, etc.

[0080] Finally, the molded body after pressurization and curing can be polished to obtain the flexible composite material of the present invention.

[0081] <Third Aspect>

[0082] The third aspect of the present invention provides a use of the flexible composite material according to the first aspect of the present invention for preparing packaging materials. The flexible composite material of the present invention is a new material with ultra-high flexibility and foldability, which can be used in the fields of document bag preparation, product packaging, special-shaped decoration, etc., and can replace plastic packaging, thereby increasing the added value of biomass products and having a very large development space.

[0083] Example

[0084] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0085] In the embodiment, the waterborne polyurethane used is a waterborne polyurethane of model 1926 produced by Yoshida Chemical Co., Ltd. The solid content of the waterborne polyurethane is about 32%, the pH value is 6-8, and the viscosity is less than 350 mPa·s.

[0086] In the embodiment, the soy protein adhesive used is the soy protein adhesive produced by Zhejiang Lange New Material Technology Co., Ltd. The soy protein adhesive has a solid content of about 40%, a pH value of 6-8, and a viscosity of 1500-4000 cp(s).

[0087] Example 1

[0088] (1) The bamboo laminated material prepared from the bamboo slices is sliced ​​to obtain a thin bamboo with a thickness of 0.146 mm.

[0089] (2) applying soybean protein adhesive to one side of the thin bamboo, and then performing hot pressing after non-woven fabric veneer, the hot pressing temperature is 90° C., and the hot pressing time is 120 seconds, to obtain a micro-thin bamboo material.

[0090] (3) preparing a sodium chlorite solution with a mass fraction of 2%, and immersing the thin bamboo material in 2) in the sodium chlorite solution for a treatment time of 10 hours to obtain a first chemical treatment product.

[0091] (4) The first chemical treatment product is washed with tap water until it becomes neutral.

[0092] (5) preparing a sodium hydroxide solution with a mass fraction of 20%, and immersing the cleaned first chemical treatment product in the sodium hydroxide solution for a treatment time of 30 seconds to obtain a second chemical treatment product, namely, a substrate.

[0093] (6) The second chemical treatment product is washed with tap water until it becomes neutral, and then dried to remove the internal moisture to obtain a dry product for later use.

[0094] (7) Inject the aqueous polyurethane solution into a high-pressure spray gun and spray the side of the dried product that is not attached to the non-woven fabric. The number of spraying times is 3 times, and the spraying amount during each spraying is 80 g / m 2 , and obtain a molded body.

[0095] (8) The molded body was placed in a press for pressurized curing at a temperature of 80°C, a time of 8 minutes, and a pressure of 2 MPa.

[0096] (9) The surface of the molded body after pressurization and curing is polished to obtain a flexible composite material.

[0097] Example 2

[0098] (1) The bamboo laminated material prepared from the bamboo slices is sliced ​​to obtain a thin bamboo with a thickness of 0.140 mm.

[0099] (2) applying soybean protein adhesive to one side of the thin bamboo, and then veneer the surface with non-woven fabric, hot pressing at 90° C. for 120 seconds, to obtain a thin bamboo material.

[0100] (3) A sodium chlorite solution with a mass fraction of 2% is prepared, and the thin bamboo material is immersed in the sodium chlorite solution for a treatment time of 72 hours to obtain a first chemical treatment product.

[0101] (4) The first chemical treatment product is washed with tap water until it becomes neutral.

[0102] (5) preparing a sodium hydroxide solution with a mass fraction of 20%, and immersing the cleaned first chemical treatment product in the sodium hydroxide solution for a treatment time of 30 seconds to obtain a second chemical treatment product, namely, a substrate.

[0103] (6) The second chemical treatment product is washed with tap water until it becomes neutral, and then dried to remove the internal moisture to obtain a dry product for later use.

[0104] (7) Inject the aqueous polyurethane solution into a high-pressure spray gun and spray the side of the dried product that is not attached to the non-woven fabric. The number of sprays is 3 times, and the spraying amount is 80 g / m 2 , and obtain a molded body.

[0105] (8) The molded body was placed in a press for pressurized curing at a temperature of 80°C, a time of 8 minutes, and a pressure of 2 MPa.

[0106] (9) The surface of the solidified molded body is polished to obtain a flexible composite material.

[0107] Example 3

[0108] (1) The bamboo laminated wood prepared from the bamboo slices is sliced ​​to obtain a thickness of 0.137 mm.

[0109] (2) applying soybean protein adhesive to one side of the thin bamboo, and then veneer with non-woven fabric, hot pressing at 90°C for 120 seconds to obtain a micro-thin bamboo material.

[0110] (3) A sodium chlorite solution with a mass fraction of 2% is prepared, and the thin bamboo material is immersed in the sodium chlorite solution for a treatment time of 72 hours to obtain a first chemical treatment product.

[0111] (4) The first chemical treatment product is washed with tap water until it becomes neutral.

[0112] (5) preparing a sodium hydroxide solution with a mass fraction of 20%, and immersing the cleaned first chemical treatment product in the sodium hydroxide solution for a treatment time of 10 seconds to obtain a second chemical treatment product, namely, a substrate.

[0113] (6) The second chemical treatment product is washed with tap water until it becomes neutral, and then dried to remove the internal moisture to obtain a dry product for later use.

[0114] (7) Inject the aqueous polyurethane solution into a high-pressure spray gun and spray the side of the dried product that is not attached to the non-woven fabric. The number of sprays is 3 times, and the spraying amount is 80 g / m 2 , and obtain a molded body.

[0115] (8) The molded body was placed in a press for pressurized curing at a temperature of 80°C, a time of 8 minutes, and a pressure of 2 MPa.

[0116] (9) The surface of the solidified molded body is polished to obtain a flexible composite material.

[0117] Comparative Example 1

[0118] One side of the sliced ​​thin bamboo was veneered with non-woven fabric, the adhesive used was soybean protein adhesive, the hot pressing temperature was 90°C, and the hot pressing time was 80 seconds. Finally, the thickness was 0.172mm, and the traditional thin bamboo material was obtained.

[0119] Performance Testing

[0120] 1. Tensile performance test

[0121] According to GB / T 12914-2018 "Constant tension method (20 mm / min) for the determination of tensile strength of paper and paperboard", the tensile properties of ultra-thin foldable bamboo-based composite materials were tested. The sample of specified size was stretched at a constant tensile speed (20 mm / min). The sample width was 15 mm ± 0.1 mm and the length was sufficient to be clamped between two clamps. The tensile strength and elongation at break were measured. The results are shown in Table 1.

[0122] 2. Folding performance test

[0123] According to GB / T "Determination of folding resistance of paper and paperboard", the folding times and folding index (folding resistance) of ultra-thin foldable bamboo-based composite materials were tested. The sample width was 15.0mm±0.1mm and the length was greater than 140mm. The MIT method was used for testing. The spring tension was adjusted to 9.81N. The folding head was fully swung 175 times±10 times per minute and the swing angle was 135°±2° with the vertical line. The results are shown in Table 1.

[0124] Table 1

[0125]

[0126] 2. Field emission electron microscope (SEM) test

[0127] The surface structure morphology and cross-sectional structure morphology of the flexible composite materials of Examples 1-3 and the conventional composite material of Comparative Example 1 were observed by field emission electron microscopy (SEM). Figure 1 shown.

[0128] in, Figure 1 a is the cross-sectional structure of the traditional thin bamboo of comparative example 1, Figure 1 b, c and d are the cross-sectional structural morphologies of Example 1, Example 2 and Example 3 respectively. Figure 1 As shown in a, the cells in the thin bamboo are plump. Figure 1 The bd shows that in the flexible composite material prepared by the preparation method of the present invention, the cells of the biomass material are squeezed. Figure 1 It can be clearly observed in the bd that the waterborne polyurethane forms a film-like protective layer on the surface of the thin bamboo. In addition, the waterborne polyurethane also penetrates into the gaps and / or pores of the bamboo cells.

[0129] Figure 1 e is the surface structure morphology of the traditional thin bamboo in comparative example 1, Figure 1 f, g and h are the surface structure morphologies of Example 1, Example 2 and Example 3 respectively. Figure 1As can be seen from images f, g, and h, the waterborne polyurethane fills the cell cavities on the thin bamboo surface, as well as the gaps and pores in the bamboo material, strengthening the connection between the cells of the biomass material.

[0130] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0131] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A flexible composite material, characterized in that: include: A matrix, wherein the matrix is ​​derived from a biomass material and is obtained by chemically treating the biomass material; as well as, An elastomeric material, wherein the elastomeric material is wrapped on the surface of the substrate to form a film-like protective layer; and, At least a portion of the elastomeric material penetrates into the interstices and / or pores of the matrix.

2. The flexible composite material according to claim 1, characterized in that: The biomass material includes wood material or bamboo material; and / or, The thickness of the biomass material is 0.1-0.6 mm, preferably 0.15-0.25 mm.

3. The flexible composite material according to claim 1 or 2, characterized in that: The chemical treatment includes chemically treating the biomass material with an alkaline substance and / or an oxide.

4. The flexible composite material according to any one of claims 1 to 3, characterized in that: The elastomeric material includes waterborne polyurethane.

5. A method for preparing the flexible composite material according to any one of claims 1 to 4, characterized in that: The preparation method comprises the steps of wrapping the elastomeric material on the surface of the substrate to form a film-like protective layer, and allowing at least a portion of the elastomeric material to penetrate into the gaps and / or pores of the substrate.

6. The preparation method according to claim 5, characterized in that: The preparation method comprises the following steps: Chemically treating the biomass material with alkaline substances and / or oxides to obtain a matrix; Obtaining an elastomer solution, wrapping the elastomer solution on the surface of the substrate to form a film-like protective layer, and allowing at least a portion of the elastomer solution to penetrate into the pores of the substrate to obtain a molded body; The molded body is subjected to a pressurizing and curing treatment to obtain a flexible composite material.

7. The preparation method according to claim 6, characterized in that: The alkaline substance includes one or a combination of two or more of KOH, NaOH, Na2SO3, K2SO3, Na2CO3, K2CO3; the oxide includes one or a combination of two or more of H2O2, NaClO2, NaClO; Preferably, the chemical treatment time is 1s-120h.

8. The preparation method according to claim 6 or 7, characterized in that: The solid content of the elastomer solution is 28-34%; and / or, The elastomer solution is wrapped on the surface of the substrate to form a film-like protective layer by one or a combination of two or more of paving, coating, casting and spraying, and at least a portion of the elastomer solution is infiltrated into the pores of the substrate.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The temperature of the pressurized curing is 60-90° C., the time of the pressurized curing is 5-10 minutes, and the pressure of the pressurized curing is 1-4 MPa.

10. Use of the flexible composite material according to any one of claims 1 to 4 for preparing packaging materials.

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