CN-117926647-B - Preparation method and application of freeze-thawing-resistant and oil-proof fluorine-free paper pulp molding device

Abstract

The invention discloses a preparation method and application of a freeze-thawing resistant and oil-proof fluorine-free paper pulp molding device. The method adopts a coarse fiber network as a framework, residual lignin and fine fibers as fillers, lignin and rosin as a hydrophobic agent and polyhydroxybutyrate as an oil-proofing agent. The pulp molding device prepared by the method has excellent rigidity and impermeability, can block hot oil penetration, and keeps structural stability and performance reliability under repeated freezing and thawing conditions. The invention provides a multi-scale structural design, which combines hydrogen bond, lignin self-crosslinking and electrostatic interaction to promote hydrophobization, densification, firm solidification and coating of a pulp molding device, solves the problems of uncontrollable deformation and poor impermeability caused by a large number of gaps and water-sensitive hydrogen bonds in a fiber network, has simple process, is environment-friendly and low in cost, expands the application potential of the pulp molding device in extreme environments such as greasiness, wet cooling, freeze thawing and the like, and can be widely applied to the fields of catering, packaging and the like.

Inventors

• LI XUSHENG
• LIU YONGFEI
• HU QINGDI
• QIU JIANSHENG
• ZHOU ZHENG
• NIE SHUANGXI
• LI QIUXIAN
• CAI CHENCHEN
• PENG WENXUAN
• SUN YUE
• TANG FANGYUAN

Assignees

• 广西大学

Dates

Publication Date

20260512

Application Date

20240125

Claims (4)

1. 1. The preparation method of the freeze-thawing resistant and oil-proof fluorine-free paper pulp molding appliance is characterized by comprising the following steps of: S1, chemically pretreating and activating lignin by using a biomass raw material, wherein the chemically pretreating is to place the biomass raw material in an aqueous solution of nitric acid with the mass concentration of 9% and hydrogen peroxide with the mass concentration of 1%, treat the biomass raw material at 50 ℃ for 6-12 hours, obtain biomass with the mass fraction of 8-17% of activated residual lignin, the carboxyl content of the activated residual lignin is not less than 0.50mmol/g, and the phenolic hydroxyl content of the activated residual lignin is not less than 0.75mmol/g; S2, blending the paper pulp prepared in the step S1 with cationic rosin emulsion, wherein the absolute dry mass ratio of the paper pulp to the absolute dry mass ratio of the cationic rosin is 100 (2-3), and then adopting vacuum filtration and hot pressing to press the blend into a dry paper pulp molding device, wherein each component is combined through hydrogen bonding, self-crosslinking of activated residual lignin and electrostatic action, and the hot pressing process comprises the steps of hot pressing for 1min at 160 ℃ and 5 MPa; S3, refining polyhydroxybutyrate powder by mechanical treatment to prepare polyhydroxybutyrate emulsion, wherein the mass fraction of the polyhydroxybutyrate emulsion is 30%, the coating amount of the polyhydroxybutyrate emulsion is 20g/m 2 , the polyhydroxybutyrate emulsion is coated on the surface of the dry paper pulp molding device prepared in the step S2, and then the polyhydroxybutyrate coating is pressed into a film by adopting hot pressing, and the hot pressing process is that the polyhydroxybutyrate coating is hot pressed for 1min at 160 ℃ and 5MPa, so that the freeze-thawing resistant and oil-proof fluorine-free paper pulp molding device is prepared.
2. 2. The method of claim 1, wherein the biomass feedstock is wood chips, bamboo chips, or bagasse.
3. 3. The preparation method according to claim 1, wherein the mass fractions of coarse fibers, medium-length fibers and fine fibers in the pulp prepared in the step S1 are 40-50%, 30-40% and 10-20%, respectively, the coarse fibers do not pass through a 20-mesh screen, the medium-length fibers do not pass through a 100-mesh screen, and the fine fibers pass through a 100-mesh screen.
4. 4. The use of the freeze-thaw resistant and oil-resistant fluorine-free pulp molding apparatus prepared by the preparation method of claim 1 in refrigeration packaging.

Description

Preparation method and application of freeze-thawing-resistant and oil-proof fluorine-free paper pulp molding device Technical Field The invention belongs to the technical field of pulp molding, and in particular relates to a preparation method of a pulp molding appliance with structural stability and performance reliability in a freeze thawing environment. Background Disposable devices are popular for their convenience and are widely used in grocery stores, accommodation facilities, offices, stations, docks, railways, airplanes and ships, with over 400 million disposable plastic devices used each year. Considering the rising industries of takeout, fresh, prepared food, etc., the consumption of disposable plastic appliances will continue to increase. Plastic devices are lightweight, inexpensive, but are not easily degradable, and disposable plastic devices remain in the consumer's hand for only a few minutes, while their natural degradation may take hundreds of years. When these discarded plastics are exposed to the natural environment, they gradually break down into microplastic and are continuously transferred from land to water, eventually penetrating into the food chain, posing a serious threat to human health and the ecological environment. Thus, there is an urgent need for a solution to make an all green substitute. Cellulose is a readily available and cost-effective natural resource with reproducibility, wide availability, biocompatibility, ease of handling, and the like. Appliances made from cellulose, a so-called pulp molding, are attractive because of their properties of mass production, wide sources of raw materials, low cost effectiveness, biodegradability, etc. However, liquid leakage and uncontrolled deformation are caused by water-sensitive hydrogen bonding and the presence of a large number of voids in the fiber network. Resistance to alternate shock from freezing and thawing is inevitable during storage, transportation and sales of pulp moulding appliances, such as pre-made food, fresh packaging liners. Repeated freeze thawing environments present a significant challenge to the reliability and durability of pulp molding appliance performance due to irreversible damage to the fiber network structure by successive attacks of water uptake swelling and ice crystal expansion. Particularly, the active technology is not satisfactory. This severely hampers the progress of replacing plastics with pulp moulding appliances. Disclosure of Invention The invention aims to provide a preparation method and application of a freeze-thawing resistant and oil-proof fluorine-free paper pulp molding device. The method relates to a multi-scale structural design, combines hydrogen bonds, activated lignin self-crosslinking and electrostatic interaction, and utilizes a hot-pressing auxiliary mode to promote hydrophobization, densification, firm solidification and coating of a pulp molding appliance, thereby solving the problems of uncontrollable deformation and poor impermeability caused by a large number of gaps and water-sensitive hydrogen bonds in a fiber network. The technical problems solved by the invention are as follows: (1) Cellulose is easy to absorb water, so that hydrogen bonds among fibers are changed into water bridge connection, and most of strength loss is the root cause of structural collapse of a pulp molding appliance. Rosin and lignin have natural water resistance, providing water stability to cellulose. However, during the processing from biomass to fiber, their strong interactions with cellulose are destroyed. When rosin and lignin are implanted into fiber networks, strength and water stability are not ideal due to insufficient adhesion. The invention proposes to enhance the interaction between the cationic rosin and the fiber by utilizing the strategy of the cationic rosin and the activated residual lignin, wherein the activated residual lignin is connected with the genetic morphology between the fiber, and the cationic rosin is combined with the fiber through electrostatic attraction, so that the wettability of the cellulose is effectively changed from hydrophilic to hydrophobic. (2) The fiber network has a large number of voids, resulting in insufficient resistance to the pulp molding tool. The invention densifies a pulp molding device through a multi-scale structural design and a hot pressing auxiliary mode, and relates to a method for compacting a pulp molding device. (3) The inter-fiber hydrogen bonds can break for a long period of time under humid or water environment, resulting in the strength of pulp molding appliances to decrease and uncontrollable deformation to occur. By introducing water stable chemical bonds into the fiber network and cooperating with hydrogen bonds, a dynamic bond and covalent bond double-crosslinked network is constructed to enhance the water stability of the pulp molding device. However, common lignin-containing products, such as unbleached pulp and alkaline hy