Modified bamboo-based fiber, bamboo fiber packaging paper and preparation method of modified bamboo-based fiber

Abstract

The invention relates to the field of bio-based materials, in particular to modified bamboo-based fibers, bamboo fiber packaging paper and a preparation method thereof.The method comprises the following steps that (S.1) soluble organic matter and lignin in bamboos are removed, and bamboo fibers only containing cellulose and hemicelluloses are obtained; (S.2) placing the bamboo fibers under an oxidizing environment condition, so that at least a part of hydroxyl groups in the bamboo fibers are converted into carbonyl groups; and (S.3) carrying out Maillard reaction on the oxidized bamboo fiber and a compound containing amino to obtain the modified bamboo fiber. The bamboo fiber in the bamboo is purified and modified, so that the mechanical property and the chemical property of the bamboo fiber are effectively improved, and the application scene of the fiber is widened. The bamboo fiber packaging paper prepared from the modified bamboo-based fiber has better durability and reliability.

Description

Technical Field

[0001] The invention relates to the field of bio-based materials, and in particular to modified bamboo-based fibers, bamboo fiber packaging paper and a preparation method thereof. Background Art

[0002] As the world pays more and more attention to environmental protection, "replacing plastic with bamboo" has become an important development trend. At the same time, the production of plastics mainly relies on non-renewable resources such as oil. As resources are gradually depleted, it becomes crucial to find sustainable alternative materials.

[0003] Bamboo-based plastic products are made of bamboo as raw material, according to standard processing procedures, with or without auxiliary materials such as stress materials including adhesives, and are made by physical and / or chemical processing methods, and are used in the packaging field to replace natural biomass materials of plastic products. The application of bamboo-based plastic products in the packaging field can be considered as packaging produced by processing bamboo materials with different physical properties through modern bamboo industry and using appropriate processing methods according to the usage scenario.

[0004] As a renewable resource, bamboo has the advantages of fast growth, wide distribution and abundant resources. Bamboo fiber has good mechanical properties, moisture absorption and air permeability, and is relatively easy to degrade in the natural environment, which is environmentally friendly. In recent years, people have continued to deepen their research and application of bamboo fiber, but there are still some shortcomings in the bamboo fiber products on the market.

[0005] For example, the performance of ordinary bamboo fiber needs to be further improved to meet the higher requirements of packaging materials in different fields. In the field of packaging paper, existing bamboo fiber packaging paper may have problems such as insufficient strength, poor moisture resistance, and poor printability. In order to overcome these shortcomings, it is necessary to modify bamboo-based fibers to improve the performance of bamboo fiber packaging paper so that it can better replace plastic products in the packaging field. Summary of the invention

[0006] The present invention aims to overcome the problems of poor strength and moisture resistance of bamboo-based fibers in the prior art, and provides a modified bamboo-based fiber, bamboo fiber packaging paper and a preparation method thereof to overcome the above-mentioned shortcomings.

[0007] To achieve the above-mentioned purpose, the present invention is implemented by the following technical solutions: In a first aspect, the present invention first provides a bamboo-based fiber surface modification method, comprising the following steps: (S.1) Removing soluble organic matter and lignin from bamboo to obtain bamboo fibers containing only cellulose and hemicellulose; (S.2) placing the bamboo fiber under oxidative environmental conditions so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups; (S.3) The oxidized bamboo fiber is subjected to a Maillard reaction with a compound containing an amino group to obtain modified bamboo fiber.

[0008] Bamboo raw materials usually contain cellulose, hemicellulose, lignin and a small amount of soluble small molecule organic matter, wherein cellulose and hemicellulose usually have linear structures, while lignin forms a three-dimensional mesh structure, and in bamboo, lignin and cellulose and other components are closely cross-linked to form a complex three-dimensional network structure. Due to the difference in the three structures of cellulose, hemicellulose and lignin, lignin has a higher hardness than cellulose and hemicellulose, but its flexibility is poor. For packaging materials, when the lignin content in its composition is too high, too high hardness is not conducive to the manufacture and use of packaging materials. Therefore, the first step in this application is to remove the soluble organic matter and lignin in the bamboo, so as to obtain the bamboo fiber that only contains cellulose and hemicellulose with excellent flexibility and strength, and the bamboo fiber can make its structure more regular after removing these impurities, which is conducive to improving its mechanical properties such as strength and toughness, so that the modified bamboo fiber and bamboo fiber packaging paper finally obtained have better durability and reliability.

[0009] In addition, the present invention selects to use Maillard reaction to modify the bamboo fiber during the modification process, the reason is: First, compared with other surface modification methods, the Maillard reaction can introduce functional groups containing nitrogen, oxygen and other heteroatoms on the surface of bamboo fibers. For example, the reaction will generate nitrogen-containing heterocyclic compounds, etc. These new functional groups can change the surface chemical properties of bamboo fibers, increase their reactive sites, and improve the interaction ability of bamboo fibers with other substances, such as enhancing the interfacial bonding with matrixes such as resins, which is very important for the preparation of high-performance bamboo fiber composites.

[0010] In addition, by controlling the conditions of the Maillard reaction, the hydrophilicity or hydrophobicity of the bamboo fiber surface can be adjusted. For example, after the reaction under certain conditions, the polarity of the bamboo fiber surface may change, making it more suitable for use in specific application environments, such as in scenarios that require good water dispersibility or in combination with hydrophobic materials.

[0011] Third, the polymer or cross-linked structure generated by the Maillard reaction may form a "shell" on the surface of the bamboo fiber, increasing the rigidity and hardness of the fiber, making it less likely to deform or break when subjected to external forces. These Maillard reaction products also usually have certain antioxidant properties, which can improve the antioxidant capacity of bamboo fibers and extend their service life. In some fields that require antioxidant properties of materials, such as biomedical materials, packaging materials, etc., bamboo fibers modified by the Maillard reaction have better application prospects.

[0012] Finally, compared with some complex chemical modification methods, the Maillard reaction is usually carried out under relatively mild conditions, and does not require the use of overly harsh reaction conditions, such as high temperature, high pressure, and highly corrosive reagents. This makes the reaction process easy to control, has low requirements for equipment, and is also conducive to reducing production costs and operational risks. In addition, the reaction can be carried out in an aqueous or organic phase system, and the treatment method for bamboo fiber is relatively flexible, which can adapt to different production processes and application requirements.

[0013] Although the Maillard reaction has the above beneficial effects, the number of groups (mainly carbonyl groups) that can participate in the Maillard reaction in cellulose and hemicellulose is small, and they are basically at the end of the molecular chain. Therefore, if the cellulose and hemicellulose are not modified, it is difficult to increase the degree of the Maillard reaction. Therefore, the present application selectively oxidizes the bamboo fiber in step (S.2), so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups, thereby greatly increasing the reaction sites of the Maillard reaction in the bamboo fiber and increasing the degree of the Maillard reaction.

[0014] Preferably, the step (S.1) specifically comprises the following steps: - Cut the bamboo into strips and crush them, then extract and remove the soluble organic matter in the bamboo strips to obtain bamboo fiber intermediates; -Putting the bamboo fiber intermediate from which soluble organic matter has been removed into a solvent capable of dissolving lignin, thereby dissolving the lignin in the bamboo, and then separating and washing to obtain a crude bamboo fiber product; - Mechanically squeeze the crude bamboo fiber product to separate the bamboo fibers from each other, and dry them to obtain the desired bamboo fibers.

[0015] The presence of lignin will affect the performance of bamboo fiber and subsequent modification reaction. Therefore, in this application, the bamboo fiber intermediate with soluble organic matter removed is placed in a solvent that can dissolve lignin, which can effectively dissolve the lignin in bamboo. The removal of lignin can improve the purity of bamboo fiber, making it more suitable for surface modification. The structure of lignin is relatively complex, which may hinder the contact between the modification agent and the bamboo fiber and affect the modification effect. After removing lignin, the surface of the bamboo fiber is more exposed, which is conducive to the subsequent modification treatment.

[0016] Preferably, the solvent capable of dissolving lignin comprises a combination of one or more of hydrochloric acid, acetic acid, dioxane, and ionic liquids, wherein the ionic liquid can be selected from 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and 1-ethyl-3-methylimidazolium acetate ([Emim]Ac). Among them, the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) can effectively dissolve lignin. It disperses lignin molecules in the ionic liquid by forming hydrogen bonds and ionic interactions with functional groups such as hydroxyl groups and carbonyl groups in the lignin molecules. And 1-ethyl-3-methylimidazolium acetate ([Emim]Ac) also has a good dissolving effect on lignin. The designability of ionic liquids makes it possible to optimize the dissolution performance of lignin by adjusting the structure of cations and anions.

[0017] In addition, under high temperature and high pressure hydrothermal conditions, water can be used as a solvent to dissolve lignin. The hydrothermal reaction can destroy the structure of lignin, breaking it down into smaller molecular fragments that can then be dissolved in water. This method is relatively environmentally friendly and does not require the use of organic solvents, but it does require higher temperature and pressure conditions.

[0018] Preferably, the step (S.2) specifically includes the following steps: The bamboo fiber is placed in an oxidative environment and heated to 80-120° C. for 0.5-5 hours.

[0019] Preferably, the oxidizing environment includes one or more of an air environment, an oxygen environment, an ozone environment, a hydrogen peroxide environment, and a potassium permanganate environment.

[0020] Preferably, in the step (S.3), the Maillard reaction temperature is 50-130°C, and the Maillard reaction time is 0.5-48h.

[0021] The inventors of the present application have found that different temperatures will affect the composition and properties of the products of the Maillard reaction. At lower temperatures, the reaction may mainly generate some primary Maillard reaction products, such as aldehydes, ketones, etc. As the temperature rises, the reaction will proceed further to generate more complex products, such as melanoidins, etc. By controlling the reaction temperature, the properties of the product can be adjusted to meet different application requirements. Too high a temperature may cause some adverse reactions, such as degradation of bamboo fiber, increased side reactions, etc. Therefore, controlling the temperature within the range of 50-130°C can minimize the adverse effects on bamboo fiber while promoting the Maillard reaction.

[0022] In addition, the Maillard reaction is usually a relatively slow process that requires a certain amount of time to fully proceed. Setting the reaction time to 0.5 - 48 hours can ensure that the carbonyl groups in the bamboo fiber have enough time to react with the amino-containing compounds, thereby improving the conversion rate of the reaction and the quality of the product. A shorter reaction time may result in an incomplete reaction, while a too long reaction time may waste energy and time and may increase the probability of side reactions.

[0023] Preferably, the amino group-containing compound includes one or more of acrylamide, vinylglycine, and maleamic acid.

[0024] The amino group-containing compounds in the present application can undergo nucleophilic addition reaction with the carbonyl group in the bamboo fiber in the Maillard reaction to form a stable chemical bond. In addition, acrylamide, vinylglycine and maleamic acid also contain unsaturated double bonds, so these unsaturated double bonds can be introduced into the bamboo fiber during the Maillard reaction, thereby expanding its subsequent applications.

[0025] In a second aspect, the present invention further provides a modified bamboo-based fiber, which is prepared by any of the methods described above.

[0026] In a third aspect, the present invention further provides a bamboo fiber packaging paper, which comprises the modified bamboo-based fiber as described above.

[0027] In a fourth aspect, the present invention further provides a method for preparing the bamboo fiber packaging paper, comprising the following steps: (S.1) beating the modified bamboo-based fiber prepared by the method to obtain bamboo-based fiber pulp; (S.2) adding fillers and additives to the bamboo-based fiber slurry to obtain composite bamboo-based fiber slurry; (S.3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (S.4) applying latex onto the surface of the semi-finished paper product, and then drying and curing the semi-finished paper product to obtain bamboo fiber packaging paper.

[0028] Preferably, in the step (S.1), the beating degree is 40-55°SR, and the pulp concentration in the bamboo-based fiber pulp is 1-2%.

[0029] Preferably, the filler in the step (S.2) is any one of silicon dioxide and calcium carbonate; the additive is any one or more combinations of surfactants, wet strength agents and antibacterial agents.

[0030] Preferably, the coating amount of latex in step (S.4) is 1-5 g / m 2 .

[0031] Therefore, the present invention has the following beneficial effects: The present invention purifies and modifies bamboo fibers in bamboo, thereby effectively improving the mechanical and chemical properties of bamboo fibers, thereby broadening the application scenarios of the fibers. The bamboo fiber packaging paper prepared by the modified bamboo-based fibers has better durability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is an electron microscope photograph of the bamboo fiber packaging paper prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0034]

Surface modification method of bamboo-based fiber

[0035] Preparation of modified bamboo-based fiber 2: The preparation method thereof comprises the following steps: (S.1) Cutting bamboo into strips and crushing them to obtain bamboo crumbs with a length of 1-5 mm, then boiling the bamboo crumbs in water for 2 hours to remove soluble organic matter, then mixing the bamboo crumbs, acetic acid and concentrated hydrochloric acid in a weight percentage of 100:500:10, reacting at 80° C. for 10 hours, filtering to obtain a filter residue, washing the filter residue to obtain a crude bamboo fiber product, mechanically extruding the crude bamboo fiber product to separate the bamboo fibers from each other, and drying to obtain bamboo fibers containing only cellulose and hemicellulose; Remove soluble organic matter and lignin from bamboo to obtain bamboo fiber containing only cellulose and hemicellulose; (S.2) placing the bamboo fiber in an environment containing 5% ozone and heating it to 100°C for 0.5 h, so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups; (S.3) The oxidized bamboo fiber was mixed with a 2% acrylamide aqueous solution at a weight ratio of 100:20, and the temperature was raised to 50° C. to perform Maillard reaction for 48 hours to obtain modified bamboo fiber 2.

[0036] Preparation of modified bamboo-based fiber 3: The preparation method thereof comprises the following steps: (S.1) Cutting bamboo into strips and crushing them to obtain bamboo crumbs with a length of 1-5 mm, then boiling the bamboo crumbs in water for 2 hours to remove soluble organic matter, then mixing the bamboo crumbs, acetic acid and concentrated hydrochloric acid in a weight percentage of 100:500:10, reacting at 80° C. for 10 hours, filtering to obtain a filter residue, washing the filter residue to obtain a crude bamboo fiber product, mechanically extruding the crude bamboo fiber product to separate the bamboo fibers from each other, and drying to obtain bamboo fibers containing only cellulose and hemicellulose; Remove soluble organic matter and lignin from bamboo to obtain bamboo fiber containing only cellulose and hemicellulose; (S.2) placing the bamboo fiber in a 2% hydrogen peroxide solution and heating it to 80°C for 0.5 h, so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups; (S.3) The oxidized bamboo fiber was mixed with a 2% acrylamide aqueous solution at a weight ratio of 100:30, and the temperature was raised to 130°C and the Maillard reaction was carried out for 0.5 h to obtain modified bamboo fiber 3.

[0037] Preparation of modified bamboo-based fiber 4: The preparation method thereof comprises the following steps: (S.1) Cutting bamboo into strips and crushing them to obtain bamboo crumbs with a length of 1-5 mm, then boiling the bamboo crumbs in water for 2 hours to remove soluble organic matter, then mixing the bamboo crumbs and dioxane in a weight percentage of 100:500, reacting at 80° C. for 12 hours, filtering to obtain a filter residue, washing the filter residue to obtain a bamboo fiber crude product, mechanically extruding the bamboo fiber crude product to separate the bamboo fibers from each other, and drying to obtain bamboo fibers containing only cellulose and hemicellulose; (S.2) placing the bamboo fiber in an air environment and heating it to 115° C. for 3 hours, so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups; (S.3) The oxidized bamboo fiber was mixed with a 2% vinylglycine aqueous solution at a weight ratio of 100:20, and the mixture was heated to 80° C. and subjected to Maillard reaction for 24 hours to obtain modified bamboo fiber 4.

[0038] Preparation of modified bamboo-based fiber 5: The preparation method thereof comprises the following steps: (S.1) Cutting bamboo into strips and crushing them to obtain bamboo crumbs with a length of 1-5 mm, then boiling the bamboo crumbs in water for 2 hours to remove soluble organic matter, then mixing the bamboo crumbs and dioxane in a weight percentage of 100:500, reacting at 80° C. for 12 hours, filtering to obtain a filter residue, washing the filter residue to obtain a bamboo fiber crude product, mechanically extruding the bamboo fiber crude product to separate the bamboo fibers from each other, and drying to obtain bamboo fibers containing only cellulose and hemicellulose; (S.2) placing the bamboo fiber in an air environment and heating it to 115° C. for 3 hours, so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups; (S.3) The oxidized bamboo fiber was mixed with a 2% maleamic acid aqueous solution at a weight ratio of 100:20, and the temperature was raised to 85° C. and Maillard reaction was performed for 28 hours to obtain modified bamboo fiber 5.

[0039] Preparation of comparative bamboo-based fiber 1: The preparation method thereof comprises the following steps: (S.1) Cutting bamboo into strips and crushing them to obtain bamboo crumbs with a length of 1-5 mm, then boiling the bamboo crumbs in water for 2 hours to remove soluble organic matter, then mixing the bamboo crumbs and dioxane in a weight percentage of 100:500, reacting at 80° C. for 12 hours, filtering to obtain a filter residue, washing the filter residue to obtain a bamboo fiber crude product, mechanically extruding the bamboo fiber crude product to separate the bamboo fibers from each other, and drying to obtain bamboo fibers containing only cellulose and hemicellulose; (S.2) Bamboo fiber and 2% maleamic acid aqueous solution were mixed at a weight ratio of 100:20, and the temperature was raised to 85° C. and Maillard reaction was performed for 28 hours to obtain a comparative bamboo-based fiber 1.

[0040] Preparation of comparative bamboo-based fiber 2: The preparation method thereof comprises the following steps: (S.1) Cutting bamboo into strips and crushing them to obtain bamboo crumbs with a length of 1-5 mm, then boiling the bamboo crumbs in water for 2 hours to remove soluble organic matter, then mixing the bamboo crumbs, acetic acid and concentrated hydrochloric acid in a weight percentage of 100:500:10, reacting at 80° C. for 10 hours, filtering to obtain a filter residue, washing the filter residue to obtain a crude bamboo fiber product, mechanically extruding the crude bamboo fiber product to separate the bamboo fibers from each other, and drying to obtain bamboo fibers containing only cellulose and hemicellulose; Remove soluble organic matter and lignin from bamboo to obtain bamboo fiber containing only cellulose and hemicellulose; (S.2) placing the bamboo fiber in an air environment and heating it to 120°C for 5 hours, so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups; (S.3) The oxidized bamboo fiber was mixed with a 2% acrylamide aqueous solution at a weight ratio of 100:10, and the temperature was raised to 80°C and the Maillard reaction was carried out for 24 hours to obtain a comparison bamboo-based fiber 2.

[0041] Preparation of modified bamboo-based fiber 3: The preparation method thereof comprises the following steps: The bamboo is cut into strips and crushed to obtain bamboo crumbs with a length of 1-5 mm, and then the bamboo crumbs are boiled in water for 2 hours to remove soluble organic matter, and then the bamboo crumbs, acetic acid and concentrated hydrochloric acid are mixed in a weight percentage of 100:500:10, and reacted at 80°C for 10 hours, and filtered to obtain a filter residue. After washing the filter residue, a crude bamboo fiber product is obtained, and the crude bamboo fiber product is mechanically extruded to separate the bamboo fibers from each other, and dried to obtain a modified bamboo-based fiber 3 containing only cellulose and hemicellulose.

[0042] Example 1 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 1 into a pulp with a concentration of 1.5%, and then beating the pulp to obtain a bamboo-based fiber pulp with a beating degree of 45°SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0043] Example 2 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 2 into a pulp with a concentration of 1.5%, and then beating the pulp to obtain a bamboo-based fiber pulp with a beating degree of 45°SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0044] Example 3 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 3 into a pulp with a concentration of 1.5%, and then beating the pulp to obtain a bamboo-based fiber pulp with a beating degree of 45°SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0045] Example 4 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 4 into a pulp with a concentration of 1.5%, and then beating the pulp to obtain a bamboo-based fiber pulp with a beating degree of 45°SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0046] Example 5 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 5 into a pulp with a concentration of 1.5%, and then beating the pulp to obtain a bamboo-based fiber pulp with a beating degree of 45°SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0047] Example 6 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 1 into a pulp with a concentration of 2%, and then beating the pulp to obtain a bamboo-based fiber pulp with a beating degree of 55°SR; (2) adding 1.5% of silica filler, 0.1% of sodium dodecylbenzene sulfonate and 0.8% of wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 5g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 8 hours to obtain bamboo fiber packaging paper.

[0048] Example 7 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 1 into a slurry with a concentration of 1%, and then beating the slurry to obtain a bamboo-based fiber slurry with a beating degree of 40°SR; (2) adding 2% silica filler, 0.1% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 1g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0049] Example 8 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) preparing the modified bamboo fiber 1 into a pulp with a concentration of 1.5%, and then beating the pulp to obtain a bamboo-based fiber pulp with a beating degree of 50°SR; (2) adding 1.5% of silica filler, 0.2% of sodium dodecylbenzene sulfonate and 0.5% of wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 2g / m 2 Then, the semi-finished paper product is cured by UV light for 30 seconds to obtain the bamboo fiber packaging paper.

[0050] Comparative Example 1 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) The comparative bamboo-based fiber 1 was prepared into a pulp with a concentration of 1.5%, and then pulped to obtain a bamboo-based fiber pulp with a beating degree of 45° SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0051] Comparative Example 2 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) The comparative bamboo-based fiber 2 was prepared into a pulp with a concentration of 1.5%, and then pulped to obtain a bamboo-based fiber pulp with a beating degree of 45° SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0052] Comparative Example 3 A bamboo fiber packaging paper, the preparation method of which comprises the following steps: (1) The comparative bamboo-based fiber 3 was prepared into a pulp with a concentration of 1.5%, and then pulped to obtain a bamboo-based fiber pulp with a beating degree of 45° SR; (2) adding 1% silica filler, 0.05% sodium dodecylbenzene sulfonate and 0.8% wet strength agent to the bamboo-based fiber slurry to obtain a composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Apply latex to the surface of the semi-finished paper. The latex contains 0.01% initiator and the coating amount of the latex is 3g / m 2 Then, the semi-finished paper product is cured and dried at 85°C for 5 hours to obtain the bamboo fiber packaging paper.

[0053] The bamboo fiber packaging papers prepared in Examples 1 to 8 and Comparative Examples 1 to 3 were tested to measure their tensile strength, tear strength, oxygen permeability, and water vapor permeability.

[0054] Among them, tensile strength and tear strength are tested according to GB / T453-2002; Oxygen permeability is tested according to GB / T19789-2005; The water vapor transmission rate was tested in accordance with GB / T22921-2008. The test results are shown in Table 1 below.

[0055] Table 1 project Tensile strength (kN / m) Tear strength (mN) <![CDATA[Oxygen transmission rate (cm 3 / cm 2 )]]> <![CDATA[Water vapor transmission rate (g / cm 2 ·day)]]> Example 1 2.82 625.5 548 162 Example 2 2.91 633.4 541 158 Example 3 3.02 639.1 537 155 Example 4 2.86 628.6 550 161 Example 5 2.95 638.2 536 156 Example 6 2.93 631.5 538 152 Example 7 2.65 618.9 556 173 Example 8 2.90 628.3 536 149 Comparative Example 1 2.36 593.9 596.1 192 Comparative Example 2 2.44 615.8 581 178 Comparative Example 3 2.09 563.5 621.5 208 From the data in the above table, it can be seen that by adding the modified bamboo fiber of the present application to the bamboo fiber packaging paper, the mechanical properties of the bamboo fiber packaging paper can be effectively improved. At the same time, its barrier properties to oxygen and water vapor can be effectively improved, so that it can be effectively used in the packaging field, thereby expanding its application range.

[0056] The specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but this will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A bamboo-based fiber surface modification method, characterized in that: The following steps are involved: (S.1) Removing soluble organic matter and lignin from bamboo to obtain bamboo fibers containing only cellulose and hemicellulose; (S.2) placing the bamboo fiber under oxidative environmental conditions so that at least a portion of the hydroxyl groups in the bamboo fiber are converted into carbonyl groups; (S.3) The oxidized bamboo fiber is subjected to a Maillard reaction with a compound containing an amino group to obtain modified bamboo fiber.

2. A bamboo-based fiber surface modification method according to claim 1, characterized in that: The step (S.1) specifically comprises the following steps: - Cut the bamboo into strips and crush them, then extract and remove the soluble organic matter in the bamboo strips to obtain bamboo fiber intermediates; -Putting the bamboo fiber intermediate from which soluble organic matter has been removed into a solvent capable of dissolving lignin, thereby dissolving the lignin in the bamboo, and then separating and washing to obtain a crude bamboo fiber product; - Mechanically squeeze the crude bamboo fiber product to separate the bamboo fibers from each other, and dry them to obtain the desired bamboo fibers.

3. The method for surface modification of bamboo-based fibers according to claim 1, characterized in that: The step (S.2) specifically includes the following steps: The bamboo fiber is placed in an oxidative environment and heated to 80-120° C. for 0.5-5 hours.

4. A bamboo-based fiber surface modification method according to claim 3, characterized in that: The oxidizing environment includes one or more of an air environment, an oxygen environment, an ozone environment, a hydrogen peroxide environment, and a potassium permanganate environment.

5. The method for surface modification of bamboo-based fibers according to claim 1, characterized in that: In the step (S.3), the Maillard reaction temperature is 50-130° C., and the Maillard reaction time is 0.5-48 h.

6. The method for surface modification of bamboo-based fibers according to claim 1, characterized in that: The amino group-containing compound includes one or more of acrylamide, vinylglycine, and maleamic acid.

7. A modified bamboo-based fiber, characterized in that: It is prepared by the method described in any one of claims 1 to 6.

8. A bamboo fiber packaging paper, characterized in that: It comprises the modified bamboo-based fiber as claimed in claim 7.

9. A method for preparing the bamboo fiber packaging paper according to claim 8, characterized in that: The following steps are involved: (1) beating the modified bamboo-based fiber prepared by the method according to any one of claims 1 to 6 to obtain bamboo-based fiber pulp; (2) adding fillers and additives to the bamboo-based fiber slurry to obtain composite bamboo-based fiber slurry; (3) subjecting the composite bamboo-based fiber slurry to sheet forming, dehydration, and drying treatments in sequence to obtain a semi-finished paper product; (4) Latex is coated on the surface of the semi-finished paper product, and then the semi-finished paper product is dried and cured to obtain bamboo fiber packaging paper.

10. The method according to claim 9, characterized in that In the step (1), the beating degree is 40-55°SR, and the pulp concentration in the bamboo-based fiber pulp is 1-2%; In step (2), the filler is any one of silicon dioxide and calcium carbonate; the additive is any one or more combinations of surfactants, wet strength agents, and antibacterial agents; The coating amount of latex in step (4) is 1-5 g / m 2 .

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