A decorative base paper with high absorbency and covering property and its preparation method

Abstract

The present invention belongs to the technical field of papermaking, and particularly relates to a decorative base paper with high absorbency and covering property and a preparation method thereof, including steps: S1, preparation of a modified composite filler; S2, preparation of a pulp; S3, preparation of a paper; the decorative base paper and the preparation method thereof of the present invention have the advantages of low cost, good absorbency and covering property of the paper.

Description

Technical Field

[0001] The present invention belongs to the technical field of papermaking, and particularly relates to a decorative base paper with high absorbency and covering property and a preparation method thereof. Background Art

[0002] Decorative base paper is a special industrial paper mainly made of high-quality wood pulp and titanium dioxide, and is processed by a special process. After printing and impregnating with melamine resin, it is mainly used as the facing paper layer, surface paper and bottom paper of artificial boards such as fiberboard and particleboard. Decorative base paper can be divided into plain decorative base paper, printable decorative base paper, surface wear-resistant base paper, balance base paper, edge banding base paper, etc. according to application characteristics and uses. The decorative materials prepared from decorative base paper have many excellent properties such as heat insulation, flame retardancy, non-warping, non-cracking, and easy cleaning, and have a variety of flower colors, rich and beautiful patterns, bright and vivid colors, and prominent layering, which are widely loved by users. In recent years, with the improvement of people's living standards, people have also put forward higher aesthetic requirements for the working, entertainment and living environments. In recent years, decorative base paper has been widely used in the decoration industry and has broad development space.

[0003] Decorative base paper is an impregnated paper, which is obtained by quickly absorbing several times its own weight of glue liquid after contacting with amino resins such as melamine formaldehyde resin and phenolic resin in an impregnating machine. The running speed of domestic horizontal impregnating machines is 30 - 40 m / min, so the impregnating time of the paper in the impregnating tank is only a few seconds. To achieve the specified sizing amount and uniform glue absorption in a short time, the paper to be impregnated must have good and stable liquid absorption performance. Otherwise, it will affect the running speed and output of impregnation, and serious quality problems such as dry flowers, white spots, foggy defects, pitted surface, and blurred patterns will appear after pressing. Therefore, the liquid absorption performance of decorative base paper is an important index that should be strictly controlled during the production process.

[0004] In addition, when the decorative base paper is laminated with the panel after printing and impregnation, it is required not to show through the bottom layer. Therefore, the decorative base paper also needs to have good covering ability. Generally, increasing the addition amount of titanium dioxide to improve the opacity of the paper is a common method in the papermaking of decorative base paper. However, the presence of a large amount of fillers can significantly affect the absorption performance of the paper sheet. When the filler content is relatively low, the absorption ability of the base paper can be improved, but when the filler content is too high, the water absorption ability will decrease.

[0005] Therefore, for those skilled in the art, how to balance the relationship between the absorbency and covering property of the paper is one of the technical keys of this research. Summary of the Invention

[0006] The purpose of the present invention is to provide a decorative base paper with high absorbency and covering property and a preparation method thereof for the above-mentioned existing technical problems.

[0007] In view of this, the present invention provides a decorative base paper with high absorbency and covering property, including the steps:

[0008] S1, Preparation of modified composite filler: First, intercalation treatment is carried out on talcum powder to obtain flaky talcum powder; then the flaky talcum powder, nano-titanium dioxide and betaine are dispersed in an appropriate amount of deionized water, stirred evenly, and left to stand at room temperature for 2 - 5 h, then washed with water, filtered, and dried to obtain the primary composite filler; then chitosan is dissolved in an appropriate amount of deionized water, and the primary composite filler is added under stirring, stirred evenly and then placed in a wet ball mill for ball milling modification treatment for 15 - 30 min. After the ball milling modification treatment, it is washed with water, filtered, and dried. The obtained solid mixture is kept at 200 - 300 °C for 10 - 30 min to obtain the modified composite filler;

[0009] S2, Slurry preparation: The absolute dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively pulped and beaten to obtain the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp, and then the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp are mixed to obtain a mixed slurry;

[0010] S3, Paper preparation: The modified composite filler prepared in step S1 is added to the mixed slurry prepared in step S2, stirred to be evenly mixed, and then successively passed through the forming section, pressing, drying, surface sizing, secondary drying, calendering, and winding to obtain the decorative base paper.

[0011] Further, in the step S1, by weight, the dosage of the talcum powder is 40 - 60 parts, the dosage of the nano-titanium dioxide is 70 - 90 parts, the dosage of the betaine is 0.01 - 0.05 parts, and the dosage of the chitosan is 0.05 - 0.1 parts.

[0012] Further, the step S1 includes:

[0013] S11, Talcum powder intercalation treatment: The talcum powder is put into deionized water, heated to 60 - 80 °C under stirring and kept warm for 2 - 5 h, then formamide is added, stirred until evenly mixed, and stirred at 70 - 90 °C for intercalation reaction for 5 - 8 h. After the intercalation reaction is completed, it is filtered, and the obtained solid substance is subjected to expansion treatment at 200 - 350 °C to obtain flaky talcum powder;

[0014] S12, Preparation of composite filler: The flaky talcum powder, nano-titanium dioxide and betaine are dispersed in an appropriate amount of deionized water, stirred evenly, and left to stand at room temperature for 2 - 5 h, then washed with water, filtered, and dried to obtain the primary composite filler;

[0015] S13, Ball milling modification treatment: Add an appropriate amount of glacial acetic acid to deionized water to prepare an aqueous glacial acetic acid solution with a concentration of 5-10%. Then dissolve the formulated amount of chitosan in the aqueous glacial acetic acid solution to prepare a chitosan solution with a chitosan content of 0.1-0.2%. Under stirring, add the composite filler starting material prepared in the above step S12, benzoic acid accounting for 3-5% of the weight of the nano-titanium dioxide, and a silane coupling agent accounting for 0.1-0.3% of the weight of the nano-titanium dioxide. After stirring evenly, place it in a wet ball mill for ball milling modification treatment for 15-30 min. After the ball milling modification treatment, wash with water, filter, and dry. Place the obtained solid mixture at 200-300 °C for heat preservation for 10-30 min to obtain the modified composite filler.

[0016] Further, the particle size of the talcum powder before intercalation is 10-30 um.

[0017] Further, in the above step S13, after the ball milling modification treatment, first place the dried solid mixture at 200-250 °C for heat preservation for 10-20 min, then raise the temperature to 280-300 °C for heat preservation for 5-10 min, and finally cool it to room temperature at a rate of 2-5 °C / min to obtain the modified composite filler.

[0018] Further, in the above step S2, the weight ratio of the absolute dry pulp sheets of softwood pulp, hardwood pulp, straw pulp, and cotton pulp is: (8-15):(70-90):(3-8):(40-60).

[0019] Further, in the above step S2, the weight ratio of the absolute dry pulp sheets of softwood pulp, hardwood pulp, straw pulp, and cotton pulp is: 10:80:5:50.

[0020] Further, in the above step S2, the beating degrees of the softwood pulp, hardwood pulp, straw pulp, and cotton pulp are respectively: 20-35°SR, 30-42°SR, 35-45°SR, and 32-40°SR.

[0021] Further, in the above step S3, the addition amount of the modified composite filler in the mixed slurry is 42-48% of the total weight of the absolute dry pulp sheets.

[0022] The decorative base paper with high absorbency and covering property prepared according to the above preparation method.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention first performs an intercalation treatment on talcum powder using an intercalating agent to obtain flaky talcum powder, and uses the flaky talcum powder as a carrier for nano-titanium dioxide. The composite filler formed by loading nano-titanium dioxide on the flaky talcum powder has a larger specific surface area, better covering power, and lower price, and can effectively improve the covering property of the decorative base paper prepared from the modified composite filler;

[0025] 2. In addition, the use of betaine and chitosan can improve the stability and dispersion ability of the composite filler formed by loading nano-titanium dioxide on the flaky talcum powder, making the decorative base paper prepared from the modified composite filler uniform and not prone to defects, and the adhesion of the modified composite filler particles to the paper fibers is high and not easy to fall off;

[0026] 3. On this basis, the stability of the combination between the modified composite filler particles and the paper fibers can be further improved through ball milling modification treatment;

[0027] 4. Through the compounding of softwood pulp, hardwood pulp, straw pulp, and cotton pulp, while maintaining the low beating degree of softwood pulp and the high beating degrees of hardwood pulp, straw pulp, and cotton pulp, the prepared mixed fibers have high strength and good liquid absorption capacity.

[0028] In summary, it can be seen that the decorative base paper and its preparation method described in the present invention have the advantages of low cost, good absorbency, and covering property of the paper. Detailed Embodiments

[0029] The technical solutions in the present application will be clearly described below in conjunction with specific embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application belong to the scope protected by the present application.

[0030] It should be noted that in the present application, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including that element.

[0031] A method for preparing a decorative base paper with high absorbency and covering property, comprising the steps:

[0032] S1. Preparation of modified composite filler: First, intercalation treatment is carried out on talc powder to obtain flaky talc powder; then the flaky talc powder, nano-titanium dioxide and betaine are dispersed in an appropriate amount of deionized water, stirred evenly, and left standing at room temperature for 2 - 5 h, then washed with water, filtered, and dried to obtain the primary composite filler; then chitosan is dissolved in an appropriate amount of deionized water, and the primary composite filler is added under stirring. After stirring evenly, it is placed in a wet ball mill for ball milling modification treatment for 15 - 30 min. After the ball milling modification treatment, it is washed with water, filtered, and dried. The obtained solid mixture is kept at 200 - 300 °C for 10 - 30 min to obtain the modified composite filler;

[0033] Among them, by weight, the dosage of the talc powder is 40 - 60 parts, the dosage of nano-titanium dioxide is 70 - 90 parts, the dosage of betaine is 0.01 - 0.05 parts, and the dosage of chitosan is 0.05 - 0.1 parts;

[0034] S2. Slurry preparation: The absolute dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively pulped and beaten to obtain the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp, and then the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp are mixed to obtain a mixed slurry;

[0035] S3. Paper preparation: Add the modified composite filler prepared in step S1 to the mixed slurry prepared in step S2, stir to make it evenly mixed, and then successively pass through the forming section of the wire part, pressing, drying, surface sizing, secondary drying, calendering, and coiling to obtain the decorative base paper.

[0036] Further, step S1 includes:

[0037] S11. Talc powder intercalation treatment: Put talc powder into deionized water, heat it to 60 - 80 °C under stirring and keep it warm for 2 - 5 h, then add formamide, stir until evenly mixed, and stir at 70 - 90 °C for intercalation reaction for 5 - 8 h. After the intercalation reaction is completed, filter, and perform expansion treatment on the obtained solid substance at 200 - 350 °C to obtain flaky talc powder;

[0038] S12. Preparation of composite filler: Disperse the flaky talc powder, nano-titanium dioxide and betaine in an appropriate amount of deionized water, stir evenly, and leave standing at room temperature for 2 - 5 h, then wash with water, filter, and dry to obtain the primary composite filler;

[0039] S13, Ball milling modification treatment: Add an appropriate amount of glacial acetic acid to deionized water to prepare an aqueous glacial acetic acid solution with a concentration of 5-10%. Then dissolve the formulated amount of chitosan in the aqueous glacial acetic acid solution to prepare a chitosan solution with a chitosan content of 0.1-0.2%. Under stirring, add the composite filler preliminaries obtained in the above step S12, 3-5% of benzoic acid based on the weight of the nano-titanium dioxide, and 0.1-0.3% of silane coupling agent based on the weight of the nano-titanium dioxide. After stirring evenly, place it in a wet ball mill for ball milling modification treatment for 15-30 min. After the ball milling modification treatment, wash with water, filter, and dry. Place the obtained solid mixture at 200-300 °C for heat preservation for 10-30 min to obtain the modified composite filler.

[0040] Furthermore, in the step S11, put 40-60 parts of talcum powder into 10-20 parts of deionized water, heat it to 60-80 °C under stirring, keep it warm for 2-5 h, and then add 10-15 parts of formamide for intercalation reaction.

[0041] Preferably, the particle size of the talcum powder before intercalation is 10-30 um.

[0042] Furthermore, in the step S12, disperse the flaky talcum powder prepared in the step S11, 70-90 parts of nano-titanium dioxide, and 0.01-0.05 parts of betaine in 100-200 parts of deionized water. After stirring evenly, let it stand at room temperature for 2-5 h, and then wash with water, filter, and dry to obtain the composite filler preliminaries.

[0043] Furthermore, in the step S13, after the ball milling modification treatment, first place the dried solid mixture at 200-250 °C for heat preservation for 10-20 min, then raise the temperature to 280-300 °C for heat preservation for 5-10 min, and finally cool it to room temperature at a rate of 2-5 °C / min to obtain the modified composite filler.

[0044] In the modified composite filler of the present invention, compared with the original talcum powder particles before intercalation, the flaky talcum powder has a larger specific surface area, a thinner thickness, and a larger attachment surface. Therefore, it can load nano-titanium dioxide well and can improve the adhesion and covering power of the modified composite filler on the paper. At the same time, the flaky talcum powder can be used as the skeleton element in the filler to enhance the paper, such as improving the tensile strength, shear strength, etc. of the paper.

[0045] In addition, talcum powder has a certain adsorbability. The flaky talcum powder obtained after intercalation and delamination treatment can well adsorb nano-titanium dioxide particles, achieve self-assembly, avoid the agglomeration of nano-titanium dioxide particles, promote the uniform distribution of the filler on the paper, and reduce the occurrence of paper quality problems. At the same time, the structure of the flaky talcum powder itself can be used to achieve the "near-planar" distribution of nano-titanium dioxide particles in the microscopic morphology, improve the optical effect of nano-titanium dioxide particles, and increase the whiteness and opacity of the paper.

[0046] Betaine is a natural, weakly alkaline organic substance with a large molecular surface area, strong hydrophilicity, and good solubility in water. In the step S12, adding betaine can reduce the liquid surface tension, promote the uniform dispersion of flaky talcum powder and nano-titanium dioxide in water, and provide a favorable environment for the uniform loading of nano-titanium dioxide on the flaky talcum powder.

[0047] In addition, the present invention can form hydrogen bonds or silanol groups between the composite filler starting materials by using benzoic acid and silane coupling agent, and realize the bonding between inorganic fillers by using the hydrogen bonds or silanol groups between particles. Finally, a filler network is formed within the modified filler composite particles. This filler network interpenetrates with the fiber network structure, intersects and penetrates with each other, generating a synergistic effect in performance, thereby enhancing the strength, liquid absorption capacity of the paper and the adhesion of the filler; and through ball milling modification treatment with a wet ball mill and high-temperature drying after the milling modification treatment, the connection between each component can be strengthened, stimulating the better play of the above effects.

[0048] Further, in the step S2, the weight ratio of the absolute dry pulp boards of the softwood pulp, hardwood pulp, straw pulp and cotton pulp is: (8 - 15):(70 - 90):(3 - 8):(40 - 60).

[0049] Preferably, in the step S2, the weight ratio of the absolute dry pulp boards of the softwood pulp, hardwood pulp, straw pulp and cotton pulp is: 10:80:5:50.

[0050] Further, in the step S2, the beating degrees of the softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively: 20 - 35°SR, 30 - 42°SR, 35 - 45°SR and 32 - 40°SR.

[0051] Further, in the step S2, the beating concentration of the softwood pulp, hardwood pulp, straw pulp and cotton pulp is 10 - 25%.

[0052] Further, in the step S3, the addition amount of the modified composite filler in the mixed slurry is 42 - 48% of the total weight of the absolute dry pulp boards.

[0053] Further, in the step S3, a wet strength agent accounting for 2-5% of the total weight of the absolutely dry pulp board and a dispersant accounting for 1-3% are added to the mixed slurry.

[0054] As some embodiments of the present invention, the wet strength agent is selected from one or more of urea-formaldehyde resin, polyamide-epichlorohydrin resin, melamine-formaldehyde resin, etc.

[0055] As some embodiments of the present invention, the dispersant is selected from one or more of polyethylene oxide, anionic polyacrylamide, HT5020, HT5040, etc.

[0056] The following specifically illustrates the highly absorbent and opaque decorative base paper and its preparation method of the present invention through specific examples:

[0057] Example 1

[0058] Preparation of modified composite filler:

[0059] S11, intercalation treatment of talcum powder: Put 40 parts of talcum powder into 10 parts of deionized water, heat to 60°C with stirring, keep warm for 2h, then add 10 parts of formamide, stir until evenly mixed, and carry out intercalation reaction at 90°C for 8h. After the intercalation reaction is completed, filter, and perform expansion treatment on the obtained solid substance at 200°C to obtain flaky talcum powder;

[0060] S12, preparation of composite filler: Disperse the flaky talcum powder, 70 parts of nano-titanium dioxide and 0.01 part of betaine in 100 parts of deionized water, stir evenly, stand at room temperature for 2h, then wash with water, filter, and dry to obtain the initial composite filler;

[0061] S13, ball milling modification treatment: Add an appropriate amount of glacial acetic acid to deionized water to prepare an aqueous glacial acetic acid solution with a concentration of 5%, then dissolve 0.05 part of chitosan in the aqueous glacial acetic acid solution to prepare a chitosan solution with a chitosan content of 0.1%. Under stirring, add the initial composite filler prepared in the step S12, 3% of benzoic acid based on the weight of the nano-titanium dioxide, and 0.1% of silane coupling agent based on the weight of the nano-titanium dioxide, stir evenly, place in a wet ball mill for ball milling modification treatment for 15min. After the ball milling modification treatment, wash with water, filter, and dry. Place the obtained solid mixture at 200°C for 30min, and then cool naturally to room temperature to obtain the modified composite filler.

[0062] Example 2

[0063] Preparation of modified composite filler:

[0064] S11, Intercalation treatment of talcum powder: Put 60 parts of talcum powder into 20 parts of deionized water, heat it to 80 °C with stirring, keep it warm for 5 h, add 15 parts of formamide, stir until evenly mixed, then stir at 70 °C for 5 h for intercalation reaction. After the intercalation reaction is completed, filter, and perform expansion treatment on the obtained solid substance at 350 °C to obtain flaky talcum powder;

[0065] S12, Preparation of composite filler: Disperse flaky talcum powder, 90 parts of nano-titanium dioxide and 0.05 part of betaine in 200 parts of deionized water, stir evenly, then let it stand at room temperature for 5 h, and then wash with water, filter, and dry to obtain the initial composite filler;

[0066] S13, Ball milling modification treatment: Add an appropriate amount of glacial acetic acid to deionized water to prepare an aqueous glacial acetic acid solution with a concentration of 10%, then dissolve 0.1 part of chitosan in the aqueous glacial acetic acid solution to prepare a chitosan solution with a chitosan content of 0.2%. Under stirring, add the initial composite filler prepared in the above step S12, 5% of benzoic acid based on the weight of the nano-titanium dioxide, and 0.3% of silane coupling agent based on the weight of the nano-titanium dioxide. After stirring evenly, place it in a wet ball mill for ball milling modification treatment for 30 min. After the ball milling modification treatment, wash with water, filter, and dry. Then, first place the dried solid mixture at 220 °C for 10 min, then raise the temperature to 280 °C and keep it warm for 10 min, and finally cool it to room temperature at a rate of 5 °C / min to obtain the modified composite filler.

[0067] Example 3

[0068] Preparation of decorative base paper:

[0069] Respectively pulp the absolute dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp, and then beat them to obtain softwood pulp, hardwood pulp, straw pulp and cotton pulp slurries. Then mix the softwood pulp, hardwood pulp, straw pulp and cotton pulp slurries to obtain a mixed slurry. Among them, the weight ratio of the absolute dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp is: 10:80:5:50, and the beating degrees of the softwood pulp, hardwood pulp, straw pulp and cotton pulp are: 21°SR, 30°SR, 37°SR and 32°SR respectively; Add the modified composite filler prepared in Example 1 above to the mixed slurry, and the addition amount of the modified composite filler in the mixed slurry is 42% of the total weight of the absolute dry pulp boards. Stir until evenly mixed, and then successively pass through the forming section, pressing, drying, surface sizing, secondary drying, calendering, and coiling to obtain the decorative base paper.

[0070] Example 4

[0071] Preparation of decorative base paper:

[0072] The dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively pulped and beaten to obtain the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp, and then the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp are mixed to obtain a mixed slurry. Among them, the weight ratio of the dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp is: 8:70:8:60, and the beating degrees of the softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively: 25°SR, 36°SR, 37°SR and 34°SR; the modified composite filler prepared in Example 2 above is added to the mixed slurry, and the addition amount of the modified composite filler in the mixed slurry is 45% of the total weight of the dry pulp boards. After stirring to make it evenly mixed, it is successively passed through the forming section, pressing, drying, surface sizing, secondary drying, calendering and winding to obtain the decorative base paper.

[0073] Example 5

[0074] Preparation of decorative base paper:

[0075] The dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively pulped and beaten to obtain the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp, and then the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp are mixed to obtain a mixed slurry. Among them, the weight ratio of the dry pulp boards of softwood pulp, hardwood pulp, straw pulp and cotton pulp is: 15:90:3:40, and the beating degrees of the softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively: 35°SR, 40°SR, 45°SR and 39°SR; the modified composite filler prepared in Example 2 above is added to the mixed slurry, and the addition amount of the modified composite filler in the mixed slurry is 48% of the total weight of the dry pulp boards. After stirring to make it evenly mixed, it is successively passed through the forming section, pressing, drying, surface sizing, secondary drying, calendering and winding to obtain the decorative base paper.

[0076] Comparative Example 1

[0077] Preparation of decorative base paper:

[0078] Compared with Example 3 above, the difference is only that it directly uses nano-titanium dioxide instead of the modified composite filler to prepare the decorative base paper.

[0079] Comparative Example 2

[0080] Preparation of decorative base paper:

[0081] Compared with Example 3 above, the difference is only that the modified composite filler used does not perform step S11, and directly uses un-intercalated talc instead of flaky talc, and prepares the modified composite filler according to steps S12 and S13 to prepare the decorative base paper.

[0082] Comparative Example 3

[0083] Preparation of Decorative Base Paper:

[0084] Compared with Example 3 above, the only difference is that benzoic acid was not added during the preparation of the modified composite filler used therein.

[0085] Comparative Example 4

[0086] Compared with Example 3 above, the only difference is that silane coupling agent was not added during the preparation of the modified composite filler used therein.

[0087] Performance Detection:

[0088] The decorative base papers prepared in Examples 3 to 5 and Comparative Examples 1 to 4 above were respectively subjected to performance detection, and the detection results are shown in Table 1 below:

[0089] Table 1 Performance Detection Results of Decorative Base Paper

[0090]

[0091] The embodiments of the present application have been described above. Without conflict, the embodiments and the features in the embodiments in the present application can be combined with each other. The present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them belong to the protection scope of the present application.

Claims

1. A method for preparing a decorative base paper with high absorbency and covering power, characterized in that, Including the steps: S1, Preparation of modified composite filler: S11, Intercalation treatment of talc powder: Put talc powder into deionized water, heat it to 60 - 80 °C with stirring, keep it warm for 2 - 5 h, then add formamide, stir until evenly mixed, and carry out intercalation reaction at 70 - 90 °C for 5 - 8 h. After the intercalation reaction is completed, filter, and subject the obtained solid substance to puffing treatment at 200 - 350 °C to obtain flaky talc powder; S12, Preparation of composite filler: Disperse the flaky talc powder, nano - titanium dioxide and betaine in an appropriate amount of deionized water, stir evenly, then let it stand at room temperature for 2 - 5 h, and then wash with water, filter, and dry to obtain the primary composite filler; S13, Ball - milling modification treatment: Add an appropriate amount of glacial acetic acid to deionized water to prepare an aqueous glacial acetic acid solution with a concentration of 5 - 10%, then dissolve the formulated amount of chitosan in the aqueous glacial acetic acid solution to prepare a chitosan solution with a chitosan content of 0.1 - 0.2%. Under stirring, add the primary composite filler prepared in step S12, benzoic acid accounting for 3 - 5% of the weight of the nano - titanium dioxide, and silane coupling agent accounting for 0.1 - 0.3% of the weight of the nano - titanium dioxide. After stirring evenly, place it in a wet ball mill for ball - milling modification treatment for 15 - 30 min. After the ball - milling modification treatment, wash with water, filter, and dry. Place the obtained solid mixture at 200 - 300 °C for heat preservation for 10 - 30 min to obtain the modified composite filler; S2, Slurry preparation: Carry out pulping and beating on the dry pulp sheets of softwood pulp, hardwood pulp, straw pulp and cotton pulp respectively to obtain the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp, and then mix the slurries of softwood pulp, hardwood pulp, straw pulp and cotton pulp to obtain a mixed slurry; S3, Paper preparation: Add the modified composite filler prepared in step S1 to the mixed slurry prepared in step S2, stir to mix evenly, and then successively go through forming on the wire section, pressing, drying, surface sizing, secondary drying, calendering, and coiling to obtain the decorative base paper; In step S2, the weight ratio of the dry pulp sheets of softwood pulp, hardwood pulp, straw pulp and cotton pulp is: (8 - 15):(70 - 90):(3 - 8):(40 - 60), and the beating degrees of softwood pulp, hardwood pulp, straw pulp and cotton pulp are respectively: 20 - 35 °SR, 30 - 42 °SR, 35 - 45 °SR and 32 - 40 °SR.

2. The method for preparing the decorative base paper according to claim 1, wherein In step S1, by weight, the dosage of talc powder is 40 - 60 parts, the dosage of nano - titanium dioxide is 70 - 90 parts, the dosage of betaine is 0.01 - 0.05 parts, and the dosage of chitosan is 0.05 - 0.1 parts.

3. The method for preparing decorative base paper according to claim 1, wherein The particle size of talc powder before intercalation is 10 - 30 μm.

4. The method for preparing the decorative base paper according to claim 1, characterized in that, In step S13, after the ball - milling modification treatment, first place the dried solid mixture at 200 - 250 °C for heat preservation for 10 - 20 min, then raise the temperature to 280 - 300 °C for heat preservation for 5 - 10 min, and finally cool it to room temperature at a rate of 2 - 5 °C / min to obtain the modified composite filler.

5. The method for preparing decorative base paper according to claim 1, wherein In the step S2, the weight ratio of the dry pulp sheets of softwood pulp, hardwood pulp, straw pulp and cotton pulp is: 10:80:5:

50.

6. The method for preparing the decorative base paper according to claim 1, characterized in that, In the step S3, the addition amount of the modified composite filler in the mixed slurry is 42-48% of the total weight of the dry pulp sheets.

7. The decorative base paper with high absorbency and opacity prepared by the preparation method according to any one of the above claims 1-6.

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