Compound pulping method for low-expansion-and-contraction-rate decorative paper-based material

Abstract

The invention relates to the field of papermaking, and particularly provides a compound pulping method for a low-expansion-and-contraction-rate decorative paper-based material. Comprising the following steps: S100, adding a compound enzyme solution into primary pulp, and carrying out an enzymolysis reaction to obtain enzymolysis pulp; s200, performing mechanical pulping on the enzymolysis slurry to obtain slurry; s300, compounding the slurry with polyamide-epichlorohydrin resin, polyacrylamide, nano silicon dioxide, titanium dioxide and nano cellulose, and performing post-treatment to obtain a low-expansion-and-contraction-rate decorative paper base; through the synergistic effect of four enzymes, the fiber separation efficiency is improved, the fiber surface is microcosmically modified, the specific surface area is increased, more hydroxyls are exposed, and hydrogen bond bonding in the papermaking process is enhanced; the polyamide-epichlorohydrin resin and polyacrylamide are crosslinked in a fiber network, so that the dry and wet strength of the paper base is improved, and the wet size deformation is reduced; the nano silicon dioxide and the nano cellulose fill up micro gaps, optimize a pore structure and inhibit moisture absorption stress, so that low expansion and contraction rate and high stability of the decorative paper are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of papermaking, in particular, it is a kind of low expansion rate decorative paper base material with compound beating method. BACKGROUND

[0002] The decorative paper base is the core layer of furniture, wallboard and other veneer materials, and its dimensional stability directly affects the decorative effect and service life of the final product. Currently, mechanical beating and chemical additives are commonly used in industry to regulate paper base performance, but traditional decorative paper has large moisture content variation in humid environment, which easily leads to paper base dimensional expansion or shrinkage, and further causes defects such as bulging, wrinkling and delamination, making it difficult to meet high-end decoration requirements.

[0003] Therefore, there is an urgent need for a new compound beating method to reduce the expansion rate of decorative paper base. SUMMARY

[0004] The present application provides a low expansion rate decorative paper base material with compound beating method, which improves the fibrillation efficiency of fibers through the synergistic effect of cellulase, xylanase, laccase and amylase, causes micro-modification of fiber surface, increases surface area and exposes more hydroxyl groups, thereby strengthening hydrogen bonding between fibers during papermaking, and forming cross-linked structure in fiber network by polyamide-epichlorohydrin resin and polyacrylamide, improving the dry and wet strength of paper base, and reducing dimensional deformation under immersion or humid environment; nano-silica and nano-cellulose not only fill the micro voids in the network, optimize the pore structure, but also construct a more robust three-dimensional skeleton with high specific surface area of nano-cellulose, further inhibit paper moisture absorption stress, and comprehensively realize low expansion rate and dimensional stability of decorative paper base material.

[0005] The present application provides a low expansion rate decorative paper base material with compound beating method, comprising the following steps: S100, adding a compound enzyme solution to the stock, and performing enzymatic reaction to obtain an enzyme hydrolysis slurry; S200, mechanically beating the enzyme hydrolysis slurry to obtain pulp; S300, wet forming, pressing treatment, drying treatment, surface sizing and calendering finishing of the pulp after compounding with polyamide-epichlorohydrin resin, cationic polyacrylamide, nano-silica, titanium dioxide and nano-cellulose to obtain a low expansion rate decorative paper base; wherein the stock is a mixed pulp of coniferous wood pulp and broadleaf wood pulp in a mass ratio of 1: (2-4); the compound enzyme solution includes 5-20 IU / g of cellulase, 5-20 IU / g of xylanase, 100-500 IU / g of laccase and 10-50 U / g of amylase.

[0006] In any of the technical solutions above, in step S100, specifically comprising: S110, adding a first complex enzyme liquid containing cellulase and xylanase into the raw pulp to perform a first enzymatic hydrolysis reaction, to obtain a first enzymatic hydrolysis pulp liquid; S120, adding a second complex enzyme liquid containing laccase and amylase into the first enzymatic hydrolysis pulp liquid, and adding a laccase synergist, to perform a second enzymatic hydrolysis reaction, to obtain a second enzymatic hydrolysis pulp liquid; wherein the laccase synergist comprises Cu 2+ at least one of complex, ABTS, and HBT.

[0007] In any of the technical solutions above, in step S110, the temperature of the first enzymatic hydrolysis reaction is 50-55℃, the pH value is 4-5, and the time is 20-40 min; in step S120, the temperature of the second enzymatic hydrolysis reaction is 55-60℃, the pH value is 5-6, and the time is 10-50 min.

[0008] In any of the technical solutions above, in step S200, the mechanical beating comprises a first beating and a second beating; wherein the beating degree of the first beating is 40-45°SR; and the beating degree of the second beating is 45-50°SR.

[0009] In any of the technical solutions above, in step S100, the fiber length of the softwood pulp is 2.1-2.8 mm; and the fiber length of the hardwood pulp is 0.8-1.2 mm.

[0010] In any of the technical solutions above, in step S300, the mass ratio of the pulp, the polyamide-epichlorohydrin resin, the polyacrylamide, the nanosilica, the titanium white powder, and the nanocellulose is 100: (1-3): (0.5-1.5): (5-10): (10-40): (0.5-5).

[0011] In any of the technical solutions above, in step S300, the surface sizing adopts a double-layer coating process, the bottom sizing agent comprises oxidized starch, the surface layer comprises fluorocarbon resin, the coating amount of the oxidized starch is 0.5-1.5 g / m 2 , and the coating amount of the fluorocarbon resin is 0.5-1.2 g / m 2 .

[0012] In any of the technical solutions above, in step S300, the linear pressure of the pressing treatment is 50-80 kN / m; and / or the temperature of the drying treatment is 60-120℃; and / or the temperature of the calender finishing is 80-100℃, and the pressure is 2-4 MPa.

[0013] In any of the technical solutions above, after step S100, further comprising an inactivation treatment: S101, heating the enzymatic hydrolysis pulp liquid to 80-85℃ and maintaining for 10-15 min, then rapidly cooling to below 40℃, and performing a centrifugal treatment or a filtration treatment.

[0014] The application also provides a low-stretch decorative paper base material prepared by any of the above methods.

[0015] The technical effects achieved by the technical scheme of the application are as follows: 1. By synergistic enzymatic hydrolysis of cellulase, xylanase, amylase and laccase, and cross-linking of polyamide-epichlorohydrin resin and polyacrylamide, the fiber surface activity and accessibility are improved, the number of hydrogen bonds between fibers is increased, and the dry and wet tensile strength and tear strength of the paper base are significantly improved; 2. The two-stage mechanical beating process realizes gradual refinement, which can reduce energy consumption under the same or higher fiber modification effect, balance production capacity and energy efficiency, and is suitable for industrial production; 3. Nano-silicon dioxide and nano-cellulose are filled and construct a three-dimensional skeleton, which fills the network micro-gap, reduces the porosity, and at the same time improves the compression resistance and moisture resistance, effectively inhibits the moisture absorption and expansion and shrinkage of paper in a humid environment; 4. Oxidized starch and fluorocarbon resin double-layer sizing are used, the bottom layer enhances the surface strength and coating adhesion, and the surface layer forms a low-surface-energy moisture-proof and stain-proof film, which not only improves the water resistance, but also takes into account the smooth hand feeling and printing adhesion performance. DETAILED DESCRIPTION

[0016] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application will be further described in detail below with specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0017] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and therefore the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0018] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below.

[0019] The decorative paper base is the core layer of the veneer material of furniture, wallboard, etc., and its dimensional stability directly affects the decoration effect and service life of the final product. At present, mechanical beating and chemical additives are commonly used in industry to regulate the performance of the paper base, but the moisture content of traditional decorative paper changes greatly in a humid environment, which easily leads to dimensional expansion or shrinkage of the paper base, and further causes defects such as bulging, wrinkling and delamination, which is difficult to meet the high-end decoration requirements.

[0020] Therefore, a new compounding beating method is needed to reduce the stretch rate of the decorative paper base.

[0021] The embodiment improves the fiber splitting efficiency by the synergistic effect of cellulase, xylanase, laccase and amylase, causes micro-modification of the fiber surface, increases the surface area and exposes more hydroxyl groups, thereby strengthening the hydrogen bond between fibers in the papermaking process, and the polyamide-epichlorohydrin resin and the polyacrylamide form a crosslinked structure in the fiber network, improve the dry and wet strength of the paper base, reduce the dimensional deformation under immersion or humid environment; nano-silicon dioxide and nano-cellulose not only fill the micro voids in the network, optimize the pore structure, but also build a more solid three-dimensional skeleton by virtue of the high specific surface area of nano-cellulose, further inhibit the hygroscopic stress of paper, and comprehensively realize the low elongation and stability of the decorative paper base material.

[0022] Specifically, a compounding beating method for a low-elongation decorative paper base material comprises the following steps: S100, adding a composite enzyme solution to the raw pulp to perform an enzymatic reaction to obtain an enzymatic pulp solution; S200, mechanically beating the enzymatic pulp solution to obtain pulp; S300, compounding the pulp with polyamide-epichlorohydrin resin, cationic polyacrylamide, nano-silicon dioxide, titanium dioxide and nano-cellulose, then performing wet forming, pressing treatment, drying treatment, surface sizing and calendering finishing to obtain a low-elongation decorative paper base; Preferably, in step S100, the raw pulp is a mixed pulp of coniferous wood pulp and broadleaf wood pulp at a mass ratio of 1: (2-4), the fiber length of the coniferous wood pulp is 2.1-2.8 mm, and the fiber length of the broadleaf wood pulp is 0.8-1.2 mm. The complementary advantages of long fibers and short fibers are utilized to maintain the tensile strength and tear resistance of the paper, on the one hand, and to improve the web forming and surface smoothness of the paper base, on the other hand, thereby realizing low elongation and dimensional stability. The coniferous wood pulp is rich in flexibility and entangling ability, can form a strong and tough fiber bridge in the paper web, and significantly improves the dry and wet strength of the paper. The broadleaf wood pulp helps to improve the uniformity of fiber distribution and web forming, so that the paper surface is more compact and smooth, and the adhesion of the printing and decorative layer is improved. Meanwhile, the fiber length and the paper strength are positively correlated, the long fibers can form a more effective hydrogen bond network inside the paper, improve the breaking resistance and tear resistance, and the entanglement of long fibers in the wet state helps to maintain the integrity of the fiber network and reduce the strength loss caused by immersion or humidity changes. The low elasticity deformation of short fibers can limit the volume expansion of the paper when it absorbs moisture, thereby assisting in realizing low elongation.

[0023] Further, in step S100, it specifically comprises: S110, adding a first composite enzyme solution containing cellulase and xylanase to the raw pulp to perform a first enzymatic reaction to obtain a first enzymatic pulp solution; S120, adding a second complex enzyme solution containing laccase and amylase into the first enzymolysis slurry, adding a laccase synergist, and performing a second enzymolysis reaction to obtain a second enzymolysis slurry; Specifically, in step S100, two-stage enzymolysis and subsequent activation are performed to pretreat cellulose, hemicellulose and lignin, and starch, respectively, and finally an oxidation mediator is introduced to form multiple modifications to the fiber network, thereby significantly improving fiber fibrillation and accessibility, reducing non-fiber components, enhancing bleaching and hydrogen bonding ability, and further stabilizing the network structure through oxidative crosslinking, thereby laying a solid foundation for subsequent mechanical beating and paper base performance. In step S110, cellulase and xylanase are used for first enzymolysis reaction at a temperature of 50-55°C, a pH value of 4-5, and a time of 20-40 min to preliminarily disperse fiber bundles and optimize fiber flexibility and interconnectivity, thereby laying a foundation for second enzymolysis and mechanical fine beating. Cellulase can hydrolyze cellulose microfiber end links in a targeted manner, cut long fibers into entangleable microfibers, increase fiber surface area and surface roughness, reduce subsequent beating energy consumption, and improve hydrogen bonding ability between fibers. Xylanase can specifically degrade the hemicellulose network in the cellulose layer, remove non-structural polysaccharides wrapped on the fiber surface, improve pulp drainage and bleaching agent permeability, and provide better accessibility for subsequent oxidative enzyme action. In step S110, laccase and amylase are used for second enzymolysis reaction at a temperature of 55-60°C, a pH value of 5-6, and a time of 10-50 min. The fiber surface modified by laccase is more easily coated with a uniform layer of pulp adjusted by amylase. Meanwhile, the reaction at a mild temperature can avoid serious damage to the fibers, and both bleaching and fiber strength are considered. Laccase is used to catalyze oxidative crosslinking or ring-opening reaction of phenolic hydroxyl groups in residual lignin, to reduce fiber color impurities and improve the effect of subsequent bleaching or resin impregnation. Meanwhile, a small amount of phenolic crosslinking structure can be formed on the fiber surface to enhance network stability. Amylase can selectively hydrolyze free or attached starch in the pulp to adjust the viscosity of the pulp, avoid uneven dispersion or equipment blockage caused by high viscosity during coating or retention aid action, and improve the uniformity of the coating layer. Finally, a laccase synergist Cu 2+ After the activation of the catalytic system, at least one of the complex, ABTS, and HBT, a small amount of crosslinked phenolic bridge and metal coordination structure is generated in the fiber network of the enzymolysis pulp, which greatly enhances the overall stability and water resistance of the fiber network, and lays a more solid micro framework for mechanical beating and complex retention aid. ABTS and HBT can be used as intermediates for laccase oxidation, and after being oxidized, they generate free radicals that can penetrate the cellulose and hemicellulose microzones, expand the action range of laccase, and significantly enhance the lignin oxidation and decolorization efficiency. Cu 2+ As a metal catalytic center, Cu

[0024] Further, after step S100, inactivation treatment is also included. After enzymolysis is completed, if the residual enzymes are not inactivated in time, the residual cellulase and xylanase can continue to act, resulting in fiber length shortening and affecting the mechanical strength of paper; in the presence of laccase enhancer, laccase can continue to oxidize lignin, causing fiber structure damage, or leading to pulp viscosity reduction, affecting subsequent sizing and coating effects. Therefore, by heating to 80-85°C and maintaining for 10-15 min, the above enzymes can be effectively inactivated to prevent their continued action in the subsequent process; after heat treatment, rapid cooling to below 40°C prevents fiber thermal degradation and maintains pulp stability; finally, centrifugation or filtration treatment is performed to remove inactivated enzymes and reaction byproducts, thereby improving pulp quality, reducing impurities, and helping to improve paper smoothness and strength.

[0025] Preferably, in step S200, mechanical beating is divided into two stages to achieve beating degrees of 40-45°SR and 45-50°SR, respectively. The two-stage beating makes the effects of different beating degrees complementary to each other, with the first stage retaining fiber length and drainage, and the second stage strengthening fiberization and bonding. The synergistic effect of the two stages can achieve high strength and low elongation at low energy consumption; the first stage beating is in a lower beating degree range, the fibers are effectively dispersed by slight shearing and extrusion, but still retain more original length, which is beneficial to maintaining basic tear resistance; and 40-45°SR belongs to the medium drainage range, which can ensure rapid drainage of the wire section during forming, shorten the forming cycle, and provide moderate humidity control for subsequent deep beating and coating processes; compared with direct beating to high beating degree, the initial stage of two-stage beating can achieve preliminary fiber modification at lower beating energy consumption, reducing total energy consumption and improving production efficiency. The second stage beating is further increased to 45-50°SR, which can significantly increase the fiber surface area and microfiberization degree, and enhance the number of hydrogen bonds and molecular chain entanglement between fibers, thereby improving dry and wet strength; under high beating degree, the bonding between fibers is enhanced, the breaking strength and tearing strength are increased, and the fiber surface is more hydrophilic, which is helpful for resin impregnation and coating adhesion; and as the beating degree increases, the pulp's water retention capacity is enhanced, which is beneficial to maintaining wet strength and water management during lamination, but needs to be balanced with retention and sizing processes for drainage and water retention.

[0026] Preferably, in step S300, the slurry is compounded with polyamide-epichlorohydrin resin, cationic polyacrylamide, nano-silicon dioxide, titanium white powder and nano-cellulose, and then wet forming, pressing treatment, drying treatment, surface sizing and calendering are performed to obtain a low-stretch decorative paper base; the polyamide-epichlorohydrin resin is a wet strength agent, which can form covalent cross-linking in the fiber network to improve the wet strength and dry strength; the polyacrylamide, preferably cationic polyacrylamide, has a charge density in the range of 1.5-2.5 meq / g, can be electrostatically adsorbed on the negatively charged cellulose surface, has a high solid retention rate in the paper machine white water, enhances the dry and wet tensile strength and reduces the loss of fillers; the nano-silicon dioxide fills the micro gaps between the fibers, homogenizes the pore structure, improves the dry stiffness and compression resistance of the paper, and plays a micro supporting role in the wet state, thereby inhibiting moisture absorption and expansion; the titanium white powder, as a high refractive index filler, not only improves the optical brightness and hiding power, but also forms micro support points in the fiber network, which cooperate with the resin cross-linking to reduce dimensional deformation; the nano-cellulose with ultra-high specific surface area constructs a three-dimensional nano-skeleton, enhances the hydrogen bonding between fibers and the cohesive force in the network, and helps to further inhibit moisture absorption stress and paper shrinkage; the reasonable proportion of additives provides uniform micro support for the fiber network.

[0027] Further, the polyamide-epichlorohydrin resin has a high solid content of 12-15%, which improves the retention efficiency of the resin in the white water and between the fibers, reduces the pollution of organic chlorides in the circulating water, and improves the process economy.

[0028] Further, the surface sizing adopts a double-layer coating process, the bottom sizing agent includes oxidized starch, the surface layer includes fluorocarbon resin, the coating amount of the oxidized starch is 0.5-1.5 g / m 2 , and the coating amount of the fluorocarbon resin is 0.5-1.2 g / m 2 . The double-layer coating process takes into account the water resistance and printing adaptability, the bottom oxidized starch improves the surface strength and adhesion of the paper, forms a dense base film, prevents the coating layer from penetrating too deeply, and optimizes the printing and finishing adhesion; the surface fluorocarbon resin further endows the surface with excellent water resistance and weather resistance, and plays a dirt-repellent and self-cleaning role due to low surface energy, and has anti-sticking and smoothness.

[0029] Preferably, the linear pressure of the pressing treatment is 50-80 kN / m, the linear pressure increase can exponentially increase the dewatering amount of the wire part, promote the close contact of the fibers, reduce the energy consumption of the subsequent drying, and using moderate process pressure in the last roll pressing area can avoid excessive compression of the fiber network, maintain moderate bulkiness and tear resistance; the temperature of the drying treatment is 60-120℃, the dewatering rate and the risk of heat damage are balanced; avoid the brightness decrease and fiber embrittlement caused by too high temperature, at the same time ensure sufficient air drying efficiency, and moderate temperature drying can obtain more uniform moisture profile, reduce paper warping and internal stress, and make the dimensional stability better; the temperature of the calender finishing is 80-100℃, and the pressure is 2-4 MPa, under the action of soft roller or hot roller, the fibers and coating materials are plastically deformed by heat, the surface irregularities are filled, the gloss and printing suitability are significantly improved, and the pressure of 2-4 MPa is enough to make the fibers and fillers micro-compacted, but will not seriously reduce the thickness, so as to balance the surface performance and the cohesion strength of the paper.

[0030] Further, the drying treatment can adopt gradient drying, the front section is 100-120℃ for rapid dewatering, and the rear section is 60-80℃ for slow drying, which can avoid high temperature embrittlement while improving efficiency.

[0031] Embodiment 1 The embodiment provides a compound beating method for low-stretch decorative paper base material, which comprises the following steps: S110, coniferous wood pulp with a fiber length of 2.5 mm is mixed with broadleaf wood pulp with a fiber length of 1 mm at a mass ratio of 1:3 to obtain raw pulp, and a first compound enzyme solution containing 10 IU / g of cellulase and 10 IU / g of xylanase is added to the raw pulp, and a first enzymolysis reaction is carried out at 52℃ and pH 4.5 for 30 min to obtain a first enzymolysis slurry; S120, a second compound enzyme solution containing 300 IU / g of laccase and 30 IU / g of amylase is added to the first enzymolysis slurry, and copper sulfate is added, and a second enzymolysis reaction is carried out at 58℃ and pH 5.5 for 20 min to obtain an enzymolysis slurry; S200, the enzymolysis slurry is subjected to two-stage mechanical beating, and the first-stage beating is to 43°SR and the second-stage beating is to 47°SR to obtain pulp; S300, the pulp is wet-formed with polyamide-epichlorohydrin resin with a solid content of 13%, cationic polyacrylamide, nano-silicon dioxide, titanium white and nano-cellulose at a mass ratio of 100:2:1:8:25:3, and then pressed at a linear pressure of 70 kN / m, followed by drying treatment at 120℃ in the front section and 60℃ in the rear section, and double-layer surface sizing is adopted: the bottom layer is coated with oxidized starch at a coating amount of 1 g / m 2 , and the surface layer is coated with fluorocarbon resin at a coating amount of 0.75 g / m 2 , and calender finishing is carried out at 90℃ and 3 MPa to obtain a low-stretch decorative paper base.

[0032] Embodiment 2 The embodiment provides a compound beating method for low-stretch decorative paper base material, which comprises the following steps: S110, coniferous wood pulp with a fiber length of 2.1 mm is mixed with broadleaf wood pulp with a fiber length of 0.8 mm at a mass ratio of 1:2 to obtain raw pulp, and a first compound enzyme solution containing 5 IU / g of cellulase and 5 IU / g of xylanase is added to the raw pulp, and a first enzymolysis reaction is carried out at 50 DEG C and pH 4 for 20 min to obtain a first enzymolysis slurry; S120, a second compound enzyme solution containing 100 IU / g of laccase and 10 IU / g of amylase is added to the first enzymolysis slurry, and ABTS is added, and a second enzymolysis reaction is carried out at 55 DEG C and pH 5 for 10 min to obtain an enzymolysis slurry; S200, the enzymolysis slurry is subjected to double-stage mechanical beating to 40 DEG SR in the first stage and to 45 DEG SR in the second stage to obtain pulp; S300, the pulp is mixed with polyamide-epichlorohydrin resin with a solid content of 12%, cationic polyacrylamide, nano-silicon dioxide, titanium white and nano-cellulose at a mass ratio of 100:1:0.5:5:10:0.5, and then wet forming is carried out, and the pulp is pressed at a linear pressure of 50 kN / m, and then dry treatment is carried out at 100 DEG C in the front stage and at 50 DEG C in the rear stage, and double-layer surface sizing is adopted, that is, the bottom layer is coated with oxidized starch at a coating amount of 0.5 g / m 2 , and the surface layer is coated with fluorocarbon resin at a coating amount of 0.5 g / m 2 , and then calendering is carried out at 80 DEG C and 2 MPa to obtain a low-stretch decorative paper base.

[0033] Embodiment 3 The embodiment provides a compound beating method for low-stretch decorative paper base material, which comprises the following steps: S110, coniferous wood pulp with a fiber length of 2.8 mm is mixed with broadleaf wood pulp with a fiber length of 1.2 mm at a mass ratio of 1:2 to obtain raw pulp, and a first compound enzyme solution containing 20 IU / g of cellulase and 20 IU / g of xylanase is added to the raw pulp, and a first enzymolysis reaction is carried out at 55 DEG C and pH 5 for 40 min to obtain a first enzymolysis slurry; S120, a second compound enzyme solution containing 500 IU / g of laccase and 50 IU / g of amylase is added to the first enzymolysis slurry, and HBT is added, and a second enzymolysis reaction is carried out at 60 DEG C and pH 6 for 50 min to obtain an enzymolysis slurry; S200, the enzymolysis slurry is subjected to double-stage mechanical beating to 45 DEG SR in the first stage and to 50 DEG SR in the second stage to obtain pulp; S300, the slurry is wet-formed with a polyamide-epichlorohydrin resin having a solid content of 15%, cationic polyacrylamide, nano-silicon dioxide, titanium white, and nano-cellulose at a mass ratio of 100:3:1.5:10:40:5, is pressed at a line pressure of 80 kN / m, and is then dried at 110 ℃ in the front section and 55 ℃ in the rear section, and is surface-sized with double layers, i.e., a bottom layer of oxidized starch at a coating amount of 1.5 g / m 2 and a top layer of fluorocarbon resin at a coating amount of 1.2 g / m 2 , is calendered at 100 ℃ and 4 MPa, and is finished to obtain a low-stretch decorative paper base.

[0034] Performance testing The wet swelling rate, dry tensile strength, wet tensile strength, smoothness, and weather resistance of Examples 1-3 were determined, and the results are shown in Table 1, with the testing methods as follows. Wet swelling rate: the sample was soaked in a constant temperature and humidity chamber at 70 ℃ and 85% relative humidity until equilibrium, and the change rates in the length, width, and thickness directions were determined, with the criterion for moisture absorption equilibrium being a change in moisture absorption of ≤0.02% for two consecutive times; the calculation formula was: wet swelling rate = (size after moisture absorption - initial size) / initial size × 100%; Dry tensile strength: a constant rate was applied until the sample was broken, and the maximum tension per unit width was calculated; Wet tensile strength: the maximum tension before breaking was determined using a tensile testing machine after the sample was soaked, and the calculation formula was: wet tensile strength = maximum tension / sample width, with the unit being kN / m; Smoothness: a Bekk smoothness tester was used to measure the time for air to pass between the sample and the glass surface, with a longer time indicating higher smoothness.

[0035] Weather resistance: a QUV ultraviolet aging chamber was used to simulate 500 hours of light exposure, and the sample was equilibrated in a standard environment, and a spectrophotometer was used to measure the lightness, red-green axis, and yellow-blue axis before and after aging, and the color difference ΔE was calculated according to the CIELAB formula.

[0036] Table 1 As can be seen from Table 1, Example 3 has the highest lignin oxidation efficiency due to the combination of the highest laccase concentration and HBT mediator, and the lowest wet swelling rate; Example 1 has the best balance of dry and wet strength due to the use of middle section beating degree and the synergistic filling of nano-silicon dioxide and cellulose; Example 3 has a dry tensile strength of 5.1 kN / m due to the highest beating degree and the highest amount of added nano-cellulose; and the smoothness and weather resistance of Example 1 are the best due to the matching of the coating amount of fluorocarbon resin and the calendering pressure.

[0037] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "certain embodiments", and the like are intended to indicate that the described implementation, feature, structure, material or characteristic is included in at least one embodiment or example of the application. Such identification of a particular embodiment or example is not intended to be exclusive of other embodiments or examples of the application that combine one described implementation, feature, structure, material or characteristic with other described implementations, features, structures, materials or characteristics. Moreover, descriptions of a particular feature, structure, material or characteristic are intended to be illustrative and not restrictive. Any implementation, feature, structure, material or characteristic of the described embodiments or examples can be combined with any other implementation, feature, structure, material or characteristic of another embodiment or example in any suitable manner without departing from the scope of the present application.

[0038] Although the present application has been disclosed in its currently best embodiment with reference to the drawings, it will be apparent to those skilled in the art that various changes and modifications can be made which will achieve some or all of the advantages mentioned, and some other advantages not presently foreseen. No limitation is accordingly intended.

Claims

1. A combined beating process for low stretch rate decor paper base materials, characterized by, The method comprises the following steps: S100, adding a complex enzyme solution to the raw pulp to perform an enzymatic hydrolysis reaction to obtain an enzymatic hydrolysis slurry; S200, mechanically beating the enzymatic hydrolysis slurry to obtain a pulp; S300, compounding the pulp with a polyamide-epichlorohydrin resin, a cationic polyacrylamide, nano-silicon dioxide, titanium white powder and nano-cellulose, and then performing wet forming, pressing treatment, drying treatment, surface sizing and calendering finishing to obtain the low-stretch decorative paper base; The raw pulp is a mixed pulp of coniferous wood pulp and broadleaf wood pulp at a mass ratio of 1: (2-4); The complex enzyme solution comprises 5-20 IU / g of cellulase, 5-20 IU / g of xylanase, 100-500 IU / g of laccase and 10-50 U / g of amylase.

2. The production method according to claim 1, characterized by, In step S100, specifically comprising: S110, adding a first complex enzyme solution containing the cellulase and the xylanase to the raw pulp to perform a first enzymatic hydrolysis reaction to obtain a first enzymatic hydrolysis slurry; S120, adding a second complex enzyme solution containing the laccase and the amylase to the first enzymatic hydrolysis slurry, adding a laccase synergist, and performing a second enzymatic hydrolysis reaction to obtain the enzymatic hydrolysis slurry; wherein the laccase booster comprises Cu 2+ at least one of a complex, ABTS, HBT.

3. The preparation method according to claim 2, characterized in that, In step S110, the first enzymatic hydrolysis reaction is performed at a temperature of 50-55℃, a pH value of 4-5 and for a time of 20-40 min; In step S120, the second enzymatic hydrolysis reaction is performed at a temperature of 55-60℃, a pH value of 5-6 and for a time of 10-50 min.

4. The preparation method according to claim 1, characterized in that, In step S200, the mechanical beating comprises one-stage beating and two-stage beating; The one-stage beating has a beating degree of 40-45°SR; The two-stage beating has a beating degree of 45-50°SR.

5. The preparation method according to claim 1, characterized in that, The coniferous wood pulp has a fiber length of 2.1-2.8 mm, and the broadleaf wood pulp has a fiber length of 0.8-1.2 mm.

6. The method of claim 1, wherein, In step S300, The mass ratio of the pulp, the polyamide-epichlorohydrin resin, the polyacrylamide, the nano-silicon dioxide, the titanium white powder and the nano-cellulose is 100: (1-3): (0.5-1.5): (5-10): (10-40): (0.5-5).

7. The preparation method according to claim 1, characterized in that, In step S300, the surface sizing is performed by a double-layer coating process, the bottom sizing agent comprises oxidized starch, the top layer comprises fluorocarbon resin, the coating amount of the oxidized starch is 0.5-1.5 g / m 2 , and the coating amount of the fluorocarbon resin is 0.5-1.2 g / m 2 .

8. The method of claim 1, wherein, In step S300, The pressing treatment has a linear pressure of 50-80 kN / m; and / or The drying treatment has a temperature of 50-140℃; and / or The calendering finishing has a temperature of 80-100℃ and a pressure of 2-4 MPa.

9. The method of claim 1, wherein, After step S100, further comprising an inactivation treatment: S101, heating the enzymatic hydrolysis slurry to 80-85℃ and maintaining for 10-15 min, then rapidly cooling to below 40℃, and performing centrifugal treatment or filtration treatment.

10. A decorative paper-based material with low shrinkage rate, characterized in that, The low-stretch decorative paper base material is prepared by any one of the methods of claims 1-9.

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