Material for paper tableware and preparation method thereof

Abstract

The invention relates to the technical field of disposable tableware, and discloses a material for paper tableware and a preparation method thereof.The preparation method comprises the steps that sugarcane fibers and bamboo fibers are pretreated to obtain a fiber mixture, and a treatment solution is collected to serve as a byproduct sugar solution; carrying out enzymolysis treatment on the fiber mixture to realize microfibrillation and release ferulic acid to obtain microfibrillated fiber pulp; fermenting and dispersing by using a byproduct sugar solution to prepare bacterial cellulose nano pulp; mixing the microfibrillated fiber pulp with bacterial cellulose nano-pulp, and carrying out enzymatic crosslinking to obtain crosslinked fiber pulp; and adding a modified sizing agent into the cross-linked fiber pulp, blending into pulp, and carrying out molding, curing, hot pressing and drying treatment to obtain the material for the paper tableware. The mechanical strength, the water resistance, the oil resistance and the thermal stability of the paper tableware material are remarkably improved, and the waste liquid load is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of disposable tableware, in particular to a material for paper tableware and a preparation method thereof. BACKGROUND

[0002] With the implementation of the policy of limiting disposable plastic products, paper tableware gradually becomes a substitute option as a renewable and degradable material. Among them, sugarcane residue fiber and bamboo fiber are often used as the main raw material for preparing paper tableware due to their abundant source, low price and strong renewability. The existing process usually obtains products by crushing, beating and compounding sugarcane residue and bamboo, and then hot pressing.

[0003] However, a large amount of liquid by-products will inevitably be produced in the above pretreatment and pulping process, and these by-products contain rich sugars and part of soluble hemicellulose. Most of the existing technologies treat these by-products as waste liquid, which not only wastes potential available resources, but also increases the burden of wastewater treatment. On the one hand, sugars and hemicellulose as a renewable carbon source and polysaccharide matrix are not fully developed and utilized; on the other hand, direct discharge of waste liquid is also not conducive to green production and low-carbon development goals.

[0004] Therefore, the existing paper tableware preparation process based on sugarcane residue and bamboo fiber still has deficiencies in resource comprehensive utilization, and an improved scheme capable of effectively utilizing by-product liquid resources is urgently needed to improve the overall resource utilization rate and reduce environmental pressure. SUMMARY

[0005] In view of this, the present application provides a material for paper tableware and a preparation method thereof, aiming to solve the problems existing in the above content.

[0006] On the one hand, the present application provides a material preparation method for paper tableware, comprising the following steps: pretreating sugarcane fiber and bamboo fiber to obtain a fiber mixture, and collecting the treatment liquid as a by-product sugar liquid; performing enzymatic treatment on the fiber mixture to achieve microfibrillation and release ferulic acid, to obtain a microfibrillated fiber pulp; fermenting and dispersing the by-product sugar liquid to prepare a bacterial cellulose nano-pulp; mixing the microfibrillated fiber pulp and the bacterial cellulose nano-pulp and performing enzymatic crosslinking to obtain a crosslinked fiber pulp; adding a modified sizing agent to the crosslinked fiber pulp and blending to form a pulp, and performing shaping, curing, hot pressing and drying treatment to finally obtain a material for producing paper tableware.

[0007] Further, the pretreatment comprises: The bagasse and bamboo are crushed to obtain bagasse fiber and bamboo fiber, which are mixed in a mass ratio of 60-70:40-30, and then a citric acid-citric acid buffer solution with a pH of 5.0-5.5 is added, with a solid-liquid ratio of 1g:10-12ml; pectinase 100-300U / g, xylanase 20-80U / g, and lipase 30-80U / g are added to the citric acid-citric acid buffer solution, and the enzyme amount is calculated based on the dry fiber basis, and mechanical stirring and intermittent ultrasonic treatment are carried out at 45-55℃ and 100-200rpm, with ultrasonic parameters of 20kHz, 150-250W, 30 seconds of ultrasonic treatment every 5 minutes, and a reaction time of 90-120 minutes.

[0008] Further, the preparation of the microfibrillated fiber pulp includes: The pretreated fiber mixture is placed in a reaction container, and endo-cellulase 10-20U / g and feruloyl esterase 10-40U / g are added, and the reaction is carried out at 45-50℃ and pH 5.0-5.5 for 60-90 minutes, and when the free ferulic acid content in the pulp reaches ≥0.8mg / g, the microfibrillated fiber pulp is obtained.

[0009] Further, the preparation of the bacterial cellulose nanosuspension includes: Cellulase 50-120U / g and β-glucosidase 20-50U / g are added to the by-product sugar solution for hydrolysis until the glucose concentration reaches 25-35g / L; After adjusting the pH to 5.0, inoculate with Xylose Klebsiella, and incubate at 28-30℃ for 96-120 hours to generate a bacterial cellulose gel film, which is then dispersed by homogenization to obtain a bacterial cellulose nanosuspension with a solid content of 1.0-2.0wt% and a fiber width of 20-80nm.

[0010] Further, the enzymatic crosslinking includes: The microfibrillated fiber pulp and the bacterial cellulose nanosuspension are mixed in a mass ratio of 96-99:1-4, and laccase 10-50U / g and hydrogen peroxide 0.02-0.05wt% are added, and the reaction is carried out at 30-40℃ and pH 5.0-5.5 for 30-60 minutes, so that the ferulic acid is oxidatively coupled to form a di-feruloyl bridge, and a crosslinked fiber pulp is obtained.

[0011] Further, the modification of the sizing agent includes: The by-product hemicellulose solution is mixed with lauric acid in a molar ratio of 1:(0.3-0.8), and the mixture is reacted in a 30% ethanol-water system at 45-50℃ for 3-5 hours in the presence of lipase 20-60U / g to obtain a hemicellulose-lauric acid lightly esterified product with a degree of substitution of 0.05-0.25, and the product is added to the crosslinked fiber pulp in an amount of 3-6wt% based on the dry fiber basis to obtain an internal sizing fiber pulp; The by-product hemicellulose solution is soluble hemicellulose solution obtained by washing the microfibrillated fiber slurry with 40-60℃ warm water or 30% volume fraction ethanol aqueous solution, and then enriching by alcohol precipitation with 60-80% volume fraction ethanol aqueous solution and / or membrane separation with a molecular weight cut-off of 3-10 kDa.

[0012] Further, the preparing the pulp comprises: The internal sizing fiber slurry is adjusted to a solid content of 12-16 wt%, and stirred at a shear rate of 300-600 s-1 for 10-15 minutes to obtain the fiber slurry for forming.

[0013] Further, the forming and the curing comprise: The fiber slurry for forming is injected into a mold, and cold-pressed at 5-8 MPa for 60-90 seconds to obtain a semi-finished body; The semi-finished body is placed in an environment of 40℃ and 80% relative humidity for 20-30 minutes to allow the residual laccase to continue to act, and a cured body is obtained.

[0014] Further, the hot-pressing and the drying comprise: The cured body is hot-pressed at 160-170℃ and 15-22 MPa for 2.5-4 minutes, and 0.3-0.8 wt% of citric acid is added as a cross-linking promoter to obtain a dense shaped body; The dense shaped body is air-dried at 60-80℃ for 20-30 minutes in a circulating air to obtain the material for paper tableware.

[0015] In another aspect, the present application also protects the paper tableware obtained by the above preparation method.

[0016] Compared with the prior art, the present application has the following beneficial effects: In the process, the present application makes full use of the liquid by-products generated in the pretreatment and enzymatic hydrolysis steps. Unlike the prior art, which usually directly discharges such by-product liquid as waste liquid, the present application proposes to convert the by-product sugar liquid into bacterial cellulose nano-slurry through hydrolysis and fermentation, and to prepare the sizing agent through enzymatic modification of the by-product hemicellulose solution, thereby improving the overall utilization rate of raw materials and reducing waste liquid discharge. This measure can reduce the pressure of wastewater treatment and enable the by-products to be functionally utilized, in line with the direction of resource recycling.

[0017] In the fiber treatment link, the present application exposes more reaction sites on the fiber surface through enzymatic microfibrillation, and releases ferulic acid. Under the subsequent laccase and hydrogen peroxide conditions, ferulic acid can undergo oxidative coupling to form covalent cross-linking bonds between fibers. Compared with relying only on physical entanglement and hydrogen bonding, this method can increase the stability of fiber-to-fiber bonding, and improve the structural retention of the obtained material in a humid heat or oil-containing environment.

[0018] In the aspect of composite reinforcement, the bacterial cellulose nanoslurry obtained by fermentation of the by-product sugar solution has good dispersibility and large specific surface area, and can play a filling and bridging role when mixed into the fiber slurry. The nanoscale network helps to improve the uniformity and structural density of the slurry, thereby improving the mechanical properties of the material to some extent, and forming a barrier to liquid penetration.

[0019] In the aspect of sizing modification, the present application uses the mild esterification product from the by-product hemicellulose solution as a sizing agent. The sizing agent introduces hydrophobic groups on the fiber surface, which helps to reduce the affinity of the fiber to water and grease, while avoiding the use of petrochemical-based adhesives, thereby maintaining the bio-based characteristics and degradability of the system.

[0020] In the aspect of forming process, the present application adopts a combination of cold pressing dewatering, enzymatic incubation curing and short-time hot pressing. Compared with the single hot pressing process with continuous high temperature and pressure, this method can achieve structural densification while reducing energy consumption DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. Embodiment 1

[0022] Take air-dried bagasse and bamboo, and use a chopper to crush them to a length of 0.3-0.8 mm. Mix them in a dry basis mass ratio of 65:35 to obtain a raw material mixture. Place the mixture in a citric acid-citric acid buffer solution with a pH of 5.2, with a solid-liquid ratio of 1 g:11 mL. Add pectinase 200 U / g, xylanase 40 U / g and lipase 50 U / g (enzyme dosage is based on the dry mass of the fiber) to the buffer solution. Treat in a constant temperature stirring reactor under the conditions of 50°C and mechanical stirring speed 150 rpm, and cooperate with an ultrasonic probe (20 kHz, 200 W) for intermittent action, 30 seconds of ultrasonic treatment every 5 minutes, for a total reaction time of 100 minutes. After the reaction is completed, filter and collect the insoluble material as a pretreated fiber mixture, and collect the filtrate as a by-product sugar solution.

[0023] Transfer the obtained pretreated fiber mixture to a reaction vessel, and add endo-cellulase 15 U / g and feruloyl esterase 30 U / g. Continue the enzymatic hydrolysis at 47°C and pH 5.2 for 75 minutes. Through high performance liquid chromatography detection, the content of free ferulic acid in the slurry reaches 0.85 mg / g (based on the dry mass of the fiber), which meets the set standard, and a microfibrillated fiber pulp is obtained.

[0024] The by-product sugar solution obtained in the step was added with cellulase 80 U / g and β-glucosidase 30 U / g, and enzymolysis was carried out at 50°C until the glucose concentration was 30 g / L. The solution pH was adjusted to 5.0, and Komagataeibacter xylinus seed solution was inoculated, and static fermentation was carried out at 29°C for 108 hours to obtain a surface-floating bacterial cellulose gel membrane. After homogenization dispersion treatment (high-speed homogenizer, 12,000 rpm, 15 minutes), bacterial cellulose nanofiber slurry with a solid content of 1.5 wt% and a fiber width of 40-60 nm was obtained.

[0025] The microfibrillated fiber slurry and the bacterial cellulose nanofiber slurry were mixed in a dry basis mass ratio of 97:3, laccase 30 U / g and hydrogen peroxide 0.03 wt% were added, and reaction was carried out at 35°C and pH 5.2 for 45 minutes. Fourier transform infrared spectroscopy detection confirmed the generation of di-feruloyl bridges, and crosslinked fiber slurry was obtained.

[0026] The fiber slurry was subjected to warm water washing in the microfibrillation step, the supernatant was collected, and soluble hemicellulose solution was obtained by 70% ethanol precipitation and 5 kDa ultrafiltration membrane separation. The solution was added with lauric acid at 10 wt% of the dry basis mass of hemicellulose, and under the action of lipase 40 U / g, reaction was carried out in a 30% ethanol-water system at 48°C for 4 hours to obtain a hemicellulose-lauric acid lightly esterified product with a degree of substitution of 0.12. The sizing agent was added to the crosslinked fiber slurry at 5 wt% of the fiber dry basis to prepare an internal sizing fiber slurry.

[0027] The internal sizing fiber slurry was adjusted to a solid content of 14 wt%, and stirring was carried out at a shear rate of 400 s⁻¹ for 12 minutes to obtain a fiber slurry for forming. The fiber slurry was injected into a mold, cold pressing was carried out at 6 MPa for 70 seconds to obtain a semi-finished blank. Subsequently, the semi-finished blank was placed in a constant temperature and humidity box at 40°C and a relative humidity of 80% for 25 minutes, so that the residual laccase continued to catalyze the crosslinking reaction, and a cured blank was obtained.

[0028] Finally, the cured blank was hot pressed at 165°C and 18 MPa for 3 minutes, and citric acid 0.5 wt% was added as a crosslinking promoter to obtain a dense and shaped blank. It was dried in a circulating air oven at 70°C for 25 minutes to obtain a final material for paper tableware.

[0029] Comparative Example 1 The difference between this comparative example and the example is that no bacterial cellulose nanofiber slurry (BCNF) is added; the other raw material ratios, enzyme treatment conditions, sizing, forming and hot pressing parameters remain consistent with the example.

[0030] Comparative Example 2 The difference between this comparative example and the example is that the enzyme-catalyzed crosslinking step of laccase / hydrogen peroxide is cancelled; the microfibrillated fiber slurry directly enters the sizing and subsequent forming, curing and hot pressing; the rest of the conditions are consistent with the example.

[0031] Comparative Example 3 The difference between this comparative example and the examples is that the sizing agent is not modified by lipase-lauric acid mild esterification, but instead an equal dry basis mass of unmodified soluble hemicellulose is added. The rest of the conditions are consistent with the examples.

[0032] Comparative Example 4 The difference between this comparative example and the examples is that the by-product sugar solution is not used to prepare BCNF by fermentation, but is directly discarded (COD / TOC index is recorded), and no BCNF is added in the subsequent pulp. The rest of the conditions are consistent with the examples.

[0033] Comparative Example 5 The difference between this comparative example and the examples is that the internal sizing agent dosage is reduced to 1 wt% of fiber dry basis (lower than 5 wt% of the examples and the scope of the claims). The rest of the conditions are consistent with the examples.

[0034] Comparative Example 6 The difference between this comparative example and the examples is that the ratio of sugarcane fiber to bamboo fiber is adjusted to 80:20 (dry basis).

[0035] In the performance verification of the examples and comparative examples, the basic physical properties of the samples are first detected. The quantitative determination of the samples is determined by ISO 536 method, the thickness and density are determined by ISO 534 method, and all samples are conditioned at 23±1℃, 50±2% relative humidity for 24 hours before detection to ensure the comparability of the data.

[0036] In terms of mechanical properties, the tensile strength and elongation at break are determined according to ISO 1924-2 method, and the sample strips are taken in the longitudinal and transverse directions respectively during testing, and the tensile testing machine is stretched to break at a speed of 20mm / min, and the average value of tensile strength and elongation at break is recorded. The bending modulus is determined according to ISO 5628 method, using three-point bending method, loading speed 10mm / min, span set according to 16 times the sample thickness, and the slope of the stress-strain curve is calculated as the bending modulus. For samples with thickness ≥0.5mm, internal bond strength test is also carried out, using TAPPI T569 Scott Bond method, and the breaking work is recorded.

[0037] In terms of water and oil resistance, water absorption was measured by ISO 535 Cobb 60 method, the sample was contacted with 100 mL water for 60 seconds, and then the water absorption was measured by weighing, expressed in g / m²; oil and fat resistance was measured by TAPPI T559 Kit level, by continuously applying standard test solution, and the highest level reached was recorded. The water contact angle was measured by the static drop method of ASTM D7334, using a contact angle measuring instrument, 5 μL of deionized water was dropped, and the contact angle values at 2 seconds and 30 seconds were recorded. In the hot water dimensional stability test, the sample was completely immersed in 90℃ deionized water for 30 minutes, after taking out, cooling to room temperature and wiping the surface moisture, the mass change rate, thickness expansion rate and warping degree were measured.

[0038] In terms of chemical indicators, the content of free ferulic acid released during the microfibrillation process was determined by high performance liquid chromatography (HPLC), using a C18 column, a mobile phase of methanol-water-acetic acid system, a detection wavelength of 320 nm, and an external standard method for quantitative determination, the results were expressed in mg / g (based on fiber dry basis). The degree of substitution of sizing agent was detected by ¹H-NMR and verified by saponification back titration method, the degree of substitution calculation formula was based on the ratio of the number of substituted hydroxyl groups to the total number of hydroxyl groups.

[0039] In terms of safety testing, in heavy metal content test, after the sample was digested with nitric acid-hydrogen peroxide, the contents of Pb and As were determined by ICP-OES, the detection limits were 0.01 mg / kg and 0.005 mg / kg respectively, and the results were compared with the limit value of food contact materials.

[0040] In terms of environmental performance, the chemical oxygen demand (COD) of by-product sugar solution and washing liquid was determined by potassium dichromate method, if necessary, TOC analyzer was used to determine the total organic carbon content, and the waste liquid load per unit product was converted into kgCOD / t product.

[0041] In terms of degradation performance, the sample was tested according to ISO 20200 composting method, the sample was placed in a soil environment with temperature of 25±2℃ and humidity of 60-80%, and was taken out and weighed at 30 days and 60 days respectively, the mass loss rate was calculated, and the morphological change was recorded to evaluate the biodegradation ability.

[0042] The detection results of the above aspects are shown in Table 1.

[0043] Table 1

[0044] From the above table, it can be seen that in the performance verification of the examples and each comparative example, the detection results show that the examples perform excellently in mechanical properties, barrier properties and environmental performance.

[0045] In terms of basic properties, the quantitative, thickness and density of the examples and the comparative examples have little difference, which indicates that the sample forming and compaction degree are consistent under the experimental conditions, facilitating lateral comparison. On this basis, the tensile strength and flexural modulus show significant differences, the tensile strength of the examples is 36.2 MPa, and the flexural modulus is 3.10 GPa, which are higher than 27.9-33.1 MPa and 2.15-2.75 GPa of the comparative examples 1-6, indicating that the introduction of bacterial cellulose nanoslurry and enzymatic crosslinking reaction significantly improves the fiber bonding strength and structural rigidity.

[0046] In terms of water and oil resistance, the Cobb60 water absorption of the examples is 17.5 g / m², which is significantly lower than 23.8-29.6 g / m² of the comparative examples 1-6; the oil and fat resistance reaches level 6, which is also better than level 3-4 of the comparative examples 1-6. At the same time, the initial static drop contact angle of the examples is 126°, and it still remains at 118° at 30 seconds, while the samples of the comparative examples are generally between 90-103°, indicating that the modified sizing agent and crosslinked structure significantly enhance the hydrophobicity and oil resistance of the finished product.

[0047] In terms of hot water dimensional stability, the thickness expansion rate of the examples after soaking is only 4.8%, while the comparative examples are generally 7.9-11.2%, among which the crosslinking-free comparative example 2 and the comparative example 6 with deviated ratio have the highest expansion rates of 10.5% and 11.2% respectively, indicating that crosslinking and fiber ratio control play a key role in maintaining dimensional stability in hot water environment.

[0048] In terms of chemical indicators, the free ferulic acid content during the microfibrillation stage of the examples reaches 0.86 mg / g, meeting the crosslinking conditions; the substitution degree of the sizing agent after modification is 0.12, which is within the designed range. The utilization efficiency of ferulic acid in comparative example 2 is significantly reduced due to the lack of crosslinking, only 0.42 mg / g, while the sizing content in comparative example 5 is insufficient, the substitution degree is reduced to 0.03, resulting in a significant decrease in barrier performance.

[0049] In terms of safety, the Pb content in all samples is less than 0.05 mg / kg, and As is not detected, which meets the safety standards for food contact materials, indicating that this method does not introduce harmful residues.

[0050] In terms of environmental protection, the COD load of the examples is 12 kg / t of product due to the full utilization of by-product sugar solution; in contrast, the COD load of comparative example 4 reaches 39 kg / t of product due to the direct disposal of sugar solution, which shows a significant environmental burden, verifying the necessity of resource utilization of by-products.

[0051] In terms of degradation performance, the mass loss rates of the embodiment at 30 days and 60 days are 45% and 88% respectively, which are significantly better than 39% and 75% of Comparative Example 6, indicating that the composite structure has both high mechanical properties and good biodegradability.

[0052] In summary, the synergistic effect of the bacterial cellulose nanoslurry prepared from the by-product sugar solution, the enzymatic ferulic acid cross-linking, and the modified hemicellulose sizing significantly improves the mechanical strength, water and oil resistance, and hot water stability of the material under the premise of safety, reduces the environmental load of the production process, and solves the problems of insufficient fiber bonding force, poor barrier performance, and waste of by-products in the prior art.

[0053] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or replaced by the equivalent, without departing from the spirit and scope of the present application, any modification or equivalent replacement should be covered within the protection scope of the claims of the present application.

Claims

1. A method for preparing a material for paper tableware, characterized in that, include: Sugarcane fiber and bamboo fiber are pretreated to obtain a fiber mixture, and the treatment liquid is collected as a by-product sugar solution. The fiber mixture is subjected to enzymatic hydrolysis to achieve microfibrilation and release ferulic acid, resulting in microfibrilated fiber pulp; By fermenting and dispersing byproduct sugar solution, bacterial cellulose nanoparticles were prepared. The microfibrillated fiber pulp was mixed with bacterial cellulose nanoparticles and then enzymatically crosslinked to obtain crosslinked fiber pulp. A modified sizing agent is added to the cross-linked fiber pulp and it is mixed into a pulp. The pulp is then subjected to molding, curing, hot pressing and drying to finally obtain the material used to produce paper tableware.

2. The method for preparing materials for paper tableware according to claim 1, characterized in that, The preprocessing includes: Sugarcane bagasse and bamboo were pulverized to obtain sugarcane fiber and bamboo fiber, which were mixed at a dry weight ratio of 60-70:40-30. A citrate-citric acid buffer solution with pH=5.0-5.5 was added, and the solid-liquid ratio was 1g:10-12ml. Pectinase 100-300U / g, xylanase 20-80U / g, and lipase 30-80U / g were added to the citrate-citric acid buffer solution. The enzyme amounts were all based on the dry weight of the fiber. The mixture was mechanically stirred and intermittently sonicated at 45-55℃ and 100-200rpm. The sonication parameters were 20kHz, 150-250W, and 30 seconds of sonication every 5 minutes for a total reaction time of 90-120min.

3. The method for preparing materials for paper tableware according to claim 1, characterized in that, The preparation of the microfibrillated fiber pulp includes: The pretreated fiber mixture was placed in a reaction vessel, and 10-20 U / g of endocellulase and 10-40 U / g of ferulic acid esterase were added. The mixture was reacted at 45-50℃ and pH 5.0-5.5 for 60-90 min. When the free ferulic acid content in the pulp reached ≥0.8 mg / g, microfibrillated fiber pulp was obtained.

4. The method for preparing materials for paper tableware according to claim 1, characterized in that, The preparation of the bacterial cellulose nanoparticles includes: Add 50-120 U / g of cellulase and 20-50 U / g of β-glucosidase to the by-product sugar solution to hydrolyze it to a glucose concentration of 25-35 g / L. After adjusting the pH to 5.0, *Xylose-1,000* was inoculated and fermented at 28-30℃ for 96-120 hours to produce a bacterial cellulose gel membrane. After homogenization and dispersion, bacterial cellulose nanoparticles with a solid content of 1.0-2.0 wt% and a fiber width of 20-80 nm were obtained.

5. The method for preparing materials for paper tableware according to claim 1, characterized in that, The enzymatic crosslinking includes: Microfibrillated fiber pulp and bacterial cellulose nanoparticle pulp were mixed at a dry weight ratio of 96-99:1-4, and laccase 10-50 U / g was added. The mixture was then reacted for 30-60 minutes at 30-40℃ and pH=5.0-5.5 under oxygen-filled conditions to allow ferulic acid to undergo oxidative coupling to form diferoyl bridges, thus obtaining cross-linked fiber pulp.

6. The method for preparing materials for paper tableware according to claim 1, characterized in that, The modification of the sizing agent includes: By adding lauric acid to a by-product hemicellulose solution at 5-20 wt% of the dry weight of the by-product hemicellulose, and reacting it at 45-50℃ for 3-5 hours in a 30% ethanol-water system under the action of lipase 20-60 U / g, a mildly esterified product of hemicellulose-lauric acid with a degree of substitution of 0.05-0.25 is obtained. This product is then added to crosslinked fiber pulp at 3-6 wt% of the dry weight of the fiber to obtain internally sized fiber pulp. The by-product hemicellulose solution is the supernatant obtained by washing the microfibrillated fiber pulp with warm water at 40-60℃ or with a 30% volume fraction of ethanol aqueous solution, followed by alcohol precipitation with a 60-80% volume fraction of ethanol aqueous solution and / or membrane separation enrichment with a molecular weight cutoff of 3-10kDa to obtain a soluble hemicellulose solution.

7. The method for preparing materials for paper tableware according to claim 1, characterized in that, The preparation of the slurry includes: The solids content of the internally sized fiber pulp is adjusted to 12-16 wt%, and the pulp is subjected to a shear rate of 300-600 s. -1 Stir for 10-15 minutes to obtain the fiber pulp for molding.

8. The method for preparing materials for paper tableware according to claim 1, characterized in that, The molding and the curing include: The fiber slurry for forming is injected into the mold and cold-pressed at 5-8MPa for 60-90 seconds to obtain a semi-finished blank. The semi-finished blank is placed in an environment of 40°C and 80% relative humidity for 20-30 minutes to allow the residual laccase to continue to act, thereby obtaining a cured blank.

9. The method for preparing materials for paper tableware according to claim 1, characterized in that, The hot pressing and the drying include: The cured preform is hot-pressed at 160-170℃ and 15-22MPa for 2.5-4 minutes, and 0.3-0.8wt% citric acid is added as a crosslinking promoter to obtain a dense and shaped preform. The dense, shaped preform is circulated and air-dried at 60-80°C for 20-30 minutes to obtain the material for paper tableware.

10. A paper tableware prepared by any one of claims 1-9.

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