A plain decorative base paper and its preparation method

Abstract

The application belongs to the technical field of papermaking, and particularly relates to a plain color decoration base paper and a preparation method thereof. The plain color decoration base paper is composed of an intermediate layer and surface layers located on the upper and lower sides of the intermediate layer. The surface layer comprises surface layer fibers and surface layer filler particles filled between the surface layer fibers. The intermediate layer comprises intermediate layer fibers and intermediate layer filler particles filled between the intermediate layer fibers. The intermediate layer filler particles are semispherical. The plain color decoration base paper has the advantages of excellent absorbability and hiding property and low cost.

Description

Technical Field

[0001] This invention belongs to the field of papermaking technology, and particularly relates to a plain decorative base paper and its preparation method. Background Technology

[0002] Decorative base paper is a special industrial paper made primarily from high-quality wood pulp and titanium dioxide through a special process. After printing and melamine resin impregnation, it is mainly used as the facing paper, surface paper, and base paper for fiberboard, particleboard, and other engineered wood products. Decorative materials made from decorative base paper possess numerous excellent properties such as heat insulation, flame retardancy, non-warping, crack resistance, and easy cleaning. They also come in a wide variety of colors and patterns, are rich and beautiful, and have a bright and vibrant appearance with a strong sense of layering, making them widely popular among users. Decorative base paper can be categorized according to its application characteristics and uses into solid-color decorative base paper, printable decorative base paper, surface abrasion-resistant base paper, balancing base paper, and edge-sealing base paper. Solid-color decorative base paper, in particular, is used for various single-color decorative base papers for engineered wood products. It must withstand high temperatures and pressures and possesses high technical content. This type of product does not require printing; after melamine resin impregnation, it can be used to produce the facing paper for various engineered wood products such as medium-density fiberboard and particleboard. Its colors are bright and vibrant, with a strong sense of layering, and it does not require secondary painting.

[0003] As can be seen from the preparation process, decorative base paper is a type of impregnated paper. After contacting amino resins, such as melamine-formaldehyde resin and phenolic resin, in the impregnation machine, it needs to rapidly absorb several times its own weight in resin solution. Currently, the speed of domestic horizontal impregnation machines is 30-40 m / min. Therefore, the paper's impregnation time in the impregnation tank is only a few seconds. To achieve the specified amount of resin and uniform absorption in a short time, the impregnated paper must have good and stable liquid absorption properties. Otherwise, it will affect the impregnation speed and output, and severe quality problems such as dried flowers, white spots, hazy defects, pitting on the board surface, and blurred patterns will occur after pressing. Therefore, the liquid absorption performance of decorative base paper is a crucial indicator that must be strictly controlled during the production process.

[0004] Furthermore, when decorative base paper is laminated to the panel after printing and impregnation, it must not show through to the underlying layer. Therefore, decorative base paper must also possess good covering power. To achieve this, titanium dioxide is generally used as a filler. Compared to other fillers, paper using titanium dioxide has better whiteness, higher strength, gloss, thinness, and smoothness, and does not show through during printing. Under the same conditions, its opacity is 10 times higher than that of calcium carbonate and talc, and its weight is reduced by 15% to 30%. Therefore, titanium dioxide can impart excellent chemical properties to paper and improve its opacity, making it an ideal filler for decorative base paper. However, titanium dioxide is expensive, increasing papermaking costs. Also, if the amount of titanium dioxide added is too high, the paper's water absorption capacity will decrease, putting it at a disadvantage in market competition; but if the amount of titanium dioxide added is too low, the paper's opacity will decrease, failing to completely cover the underlying layer.

[0005] Therefore, for those skilled in the art, providing a solid-color decorative base paper with excellent absorbency and opacity and low cost, and its preparation method, is one of the urgent technical problems to be solved. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned technical problems by providing a plain decorative base paper with excellent absorbency and opacity, and a low cost, as well as a method for its preparation.

[0007] In view of this, the present invention provides a plain decorative base paper, which is composed of an intermediate layer and surface layers located on its upper and lower sides, wherein the surface layer includes surface layer fibers and surface layer filler particles filled between the surface layer fibers, and the intermediate layer includes intermediate layer fibers and intermediate layer filler particles filled between the intermediate layer fibers, wherein the intermediate layer filler particles are hemispherical.

[0008] Furthermore, the thickness of the intermediate layer is 0.4–0.6 mm, and the thickness of the surface layer is 0.2–0.3 mm.

[0009] Furthermore, the radius of the intermediate layer filler particles is 60% to 80% of the thickness of the intermediate layer.

[0010] Furthermore, the surface layer fibers include: 20-30 parts by weight of coniferous wood fiber, 60-80 parts by weight of broadleaf wood fiber, and 20-30 parts by weight of kapok fiber.

[0011] Furthermore, the surface filler particles are one or more of spherical, spindle-shaped, dumbbell-shaped, and needle-shaped titanium dioxide particles.

[0012] Furthermore, the average particle size of the surface filler particles is 0.1–0.3 μm.

[0013] Furthermore, the intermediate layer fiber comprises 40-60 parts by weight of core-sheath polyester fiber and 40-60 parts by weight of cotton fiber. The sheath of the core-sheath polyester fiber is a low-melting-point polyester with a melting point between 100 and 150°C, and the core is a polyester with a melting point between 250 and 270°C. The sheath of the core-sheath polyester fiber accounts for 20-40% of the total fiber weight, and the core accounts for 60-80% of the total fiber weight.

[0014] Furthermore, the intermediate layer filler particles are hemispherical calcium carbonate particles.

[0015] Furthermore, the preparation process of the intermediate layer filler particles is as follows: At room temperature, calcium chloride is first dissolved in an appropriate amount of water to prepare a calcium chloride solution with a concentration of 0.1-0.3 mol / L. Then, acid is added to adjust the pH value of the calcium chloride solution to 3-5. Then, dextrin is added to the obtained calcium chloride solution under stirring, with an addition amount of 0.1-0.3 mol / L. After stirring evenly, the mixture is heated to 60-80℃ and kept at this temperature for 10-20 min under stirring. Then, a mixed gas of NH3 and CO2 is introduced into the mixture for reaction, and the reaction time is 3-5 h. The flow rate of the mixed gas is 0.5-2 mL / min, and the volume ratio of NH3 to CO2 in the mixed gas is 1:1. After the reaction is completed, the obtained solid material is filtered, washed with water, and washed with alcohol in sequence. The obtained solid material is then added to a dopamine hydrochloride solution and reacted at room temperature under stirring for 2-3 h. Finally, it is spray-dried to obtain the intermediate layer filler particles.

[0016] Furthermore, the present invention also provides a method for preparing a plain-colored decorative base paper, the method being used to prepare the aforementioned plain-colored decorative base paper, the method comprising the following steps:

[0017] S1, Preparation of surface slurry: The oven-dried pulp boards of softwood pulp, hardwood pulp and kapok pulp are crushed separately according to the weight ratio, mixed and soaked in an alkaline solution with a concentration of 3-5% for 3-5 days. Then, they are rinsed with water until neutral and dried to a moisture content of 40-50%. The dried plant fibers and an appropriate amount of swelling agent are then placed in a microwave device and microwaved for 1-2 minutes at a frequency of 1000-2000MHz and a power of 300-500W. After microwave treatment, the pulp is beaten to obtain a mixed slurry. An appropriate amount of surface filler particles are added to the mixed slurry and stirred to mix evenly to obtain the surface slurry.

[0018] S2, Preparation of intermediate layer slurry: Take an appropriate amount of oven-dry cotton fiber pulp board and core-sheath polyester fiber according to the weight ratio. Then, break the oven-dry cotton fiber pulp board into pulp and beat it to obtain cotton pulp slurry. Then, mix the core-sheath polyester fiber with an appropriate amount of water to prepare a core-sheath polyester fiber suspension with a concentration of 0.5-1%. Then, mix the cotton pulp slurry and the core-sheath polyester fiber suspension, add intermediate layer filler particles, and stir evenly to obtain intermediate layer slurry.

[0019] S3, Preparation of plain decorative base paper: On a slanted wire paper machine or long wire paper machine with three independent flow channels, the surface slurry obtained in step S1 is used as the upper slurry and the lower slurry, and the intermediate slurry obtained in step S2 is used as the intermediate slurry. The paper is formed simultaneously and then dried at 150-180°C. After that, the surface of the dried paper is smoothed by hot press rolls, wherein the temperature of the hot press rolls is 50-80°C.

[0020] The beneficial effects of this invention are as follows: In the solid-color decorative base paper, since the intermediate layer filler particles are hemispherical, their planes are in a highly unstable state in the vertical direction during paper formation. Therefore, one side of the plane in the intermediate layer filler particles can spontaneously adjust to a position above or below the intermediate layer filler particles, especially the lower side. This creates cavities of a certain volume and relatively fixed shape and position between the intermediate layer filler particles. The presence of these cavities increases the paper's bulkiness, allowing the liquid to be stored within them after absorption, significantly improving the paper's liquid absorption capacity. Simultaneously, the arrangement of the two side layers and the overall three-layer composite structure provide the paper with excellent mechanical properties, opacity, and transparency. Furthermore, since the intermediate layer filler particles are located inside the paper, other inexpensive fillers, such as calcium carbonate and silicon dioxide, can be used instead of traditional titanium dioxide, giving the solid-color decorative base paper of this invention the advantages of excellent absorbency and opacity, as well as low cost. Attached Figure Description

[0021] Figure 1 This is a first structural schematic diagram of the plain decorative base paper described in this invention;

[0022] Figure 2 This is a schematic diagram of the second structure of the plain decorative base paper described in this invention;

[0023] Figure 3 This is a third structural schematic diagram of the plain decorative base paper described in this invention;

[0024] The markings in the diagram are as follows:

[0025] 1. Surface layer; 101. Surface layer fiber; 102. Surface layer filler particles; 2. Intermediate layer; 201. Intermediate layer fiber; 202. Intermediate layer filler particles. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0027] In the description of this application, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0028] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0029] It should be noted that in the description of this application, the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0030] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0031] A type of plain decorative base paper, such as Figures 1-3 As shown, it is composed of an intermediate layer 2 and surface layers 1 located on its upper and lower sides. The surface layer 1 includes surface fibers 101 and surface filler particles 102 filled between the surface fibers 101. The intermediate layer 2 includes intermediate fibers 201 and intermediate filler particles 202 filled between the intermediate fibers 201. The intermediate filler particles 202 are hemispherical.

[0032] In the solid-color decorative base paper, since the intermediate layer filler particles 202 are hemispherical, their planes are extremely unstable in the vertical direction during paper formation. Therefore, one side of the plane in the intermediate layer filler particle 202 can spontaneously adjust to a position above or below the intermediate layer filler particle 202, especially the lower side. In this way, a shape like... Figures 1-2 The paper structure shown, wherein, Figure 1 This is a schematic diagram of the structure under ideal conditions; Figure 2This is a schematic diagram of the structure in its actual state. At this point, cavities of a certain volume and relatively fixed shape and position are formed between the intermediate layer filler particles 202. The presence of these cavities increases the paper's bulkiness, allowing the liquid to be stored within them after absorption, significantly improving the paper's absorbency. Simultaneously, the arrangement of the two side layers 1 and the overall three-layer composite structure provide the paper with good mechanical properties, opacity, and transparency. Furthermore, since the intermediate layer filler particles 202 are located inside the paper, other inexpensive fillers, such as calcium carbonate and silicon dioxide, can be used instead of traditional titanium dioxide, giving the solid-color decorative base paper of this invention the advantages of excellent absorbency and opacity, as well as low cost.

[0033] Preferably, the thickness of the plain decorative base paper is 0.8 to 1.2 mm.

[0034] Furthermore, the thickness of the intermediate layer 2 is greater than the thickness of the surface layer 1.

[0035] Preferably, the thickness of the intermediate layer 2 is 0.4 to 0.6 mm, and the thickness of the surface layer 1 is 0.2 to 0.3 mm.

[0036] Furthermore, the radius of the intermediate layer filler particles 202 is 0.05 to 0.5 mm, and preferably, the radius of the intermediate layer filler particles 202 is 60% to 80% of the thickness of the intermediate layer 2.

[0037] Furthermore, the length of the surface layer fiber 101 is less than the length of the intermediate layer fiber 201.

[0038] Preferably, the length of the intermediate layer fiber 201 is 2 to 5 times the length of the surface layer fiber 101.

[0039] As some embodiments of the present invention, the surface fiber 101 is one or more of coniferous wood fiber, broadleaf wood fiber, grass fiber, and kapok fiber.

[0040] Preferably, the surface fiber 101 is a mixture of coniferous wood fiber, broadleaf wood fiber and kapok fiber.

[0041] More preferably, the surface fiber 101 comprises: 20-30 parts by weight of coniferous wood fiber, 60-80 parts by weight of broadleaf wood fiber and 20-30 parts by weight of kapok fiber.

[0042] Among the mixed fibers constituting the surface layer fiber 101, coniferous wood fibers have long fiber length, thicker cell walls, and higher density, resulting in higher strength. Using them in the surface layer fiber 101 can improve the mechanical strength of the surface layer 1. Broadleaf wood fibers are widely available, inexpensive, short and coarse, and easy to pulp. Paper made from them has a loose structure, good absorbency, and high opacity. Using them extensively in the surface layer fiber 101 can reduce the cost of the surface layer 1, improve its production efficiency, and simultaneously enhance the paper's absorbency and opacity. Furthermore, kapok fibers are lightweight, highly hollow, and have strong hygroscopicity. Their fineness is extremely low; for example, kapok fibers are only about half the fineness of other fibers, yet their hollowness is over 85%. Using them in the surface layer fiber 101 can increase the porosity of the surface layer 1, promoting improved liquid absorption. More importantly, kapok fibers have a relatively high wax content, which can dissolve at high temperatures, acting as an adhesive for the intermediate layer 2, allowing the intermediate layer 2 and the surface layer 1 to be better bonded together.

[0043] Furthermore, the surface filler particles 102 are one or more of spherical, spindle-shaped, dumbbell-shaped, and needle-shaped titanium dioxide particles.

[0044] As some embodiments of the present invention, the surface filler particles 102 can be titanium dioxide particles of a single material, or they can be composite filler particles with non-metallic particles, such as silicon dioxide, calcium carbonate, talc, etc., as the core material and titanium dioxide particles coated on the surface.

[0045] Preferably, the average particle size of the surface filler particles 102 is 0.1–0.3 μm; more preferably, the average particle size of the surface filler particles 102 is 0.2 μm. When the particle size of the titanium dioxide filler is around 0.2 μm, the scattering coefficient of titanium dioxide is the highest, and at this point, the decolorizing ability and hiding ability of titanium dioxide are the highest.

[0046] Furthermore, the intermediate layer fiber 201 is a mixed fiber composed of core-sheath polyester fiber and cotton fiber.

[0047] Preferably, the intermediate layer fiber 201 comprises 40-60 parts by weight of core-sheath polyester fiber and 40-60 parts by weight of cotton fiber. The sheath of the core-sheath polyester fiber is a low-melting-point polyester with a melting point between 100 and 150°C, and the core is a conventional polyester with a melting point between 250 and 270°C. The sheath of the core-sheath polyester fiber accounts for 20-40% of the total fiber weight, and the core accounts for 60-80% of the total fiber weight.

[0048] In the intermediate layer fiber 201, the core-sheath polyester fiber, as a special chemical fiber, has a sheath made of low-melting-point polyester and a core made of conventional polyester. Under the high temperatures during papermaking, the sheath of the core-sheath polyester fiber can melt and adhere to the cotton fiber, intermediate layer filler particles 202, and surface layer 1, making them more firmly bonded together. Furthermore, polyester chemical fibers generally have higher strength than ordinary plant fibers; therefore, the addition of core-sheath polyester fiber can improve the mechanical strength of the paper. Cotton fiber has excellent liquid absorption capacity. Using core-sheath polyester fiber and cotton fiber in the intermediate layer 2 can form an interpenetrating network structure that fixes the intermediate layer filler particles 202 and liquid-absorbing chambers, giving the intermediate layer 2 good mechanical strength and liquid absorption and retention capabilities.

[0049] Furthermore, the intermediate layer filler particles 202 are calcium carbonate particles.

[0050] As some embodiments of the present invention, the intermediate layer filler particles 202 are hemispherical calcium carbonate particles with uniform particle size.

[0051] As some embodiments of the present invention, such as Figure 3 As shown, the intermediate layer filler particles 202 include small particles with a particle size of 50-100 μm and large particles with a particle size of 300-500 μm.

[0052] Furthermore, the preparation process of the intermediate layer filler particles 202 is as follows: At room temperature, calcium chloride is first dissolved in an appropriate amount of water to prepare a calcium chloride solution with a concentration of 0.1-0.3 mol / L. Then, acid is added to adjust the pH value of the calcium chloride solution to 3-5. Then, dextrin is added to the obtained calcium chloride solution under stirring, with an addition amount of 0.1-0.3 mol / L. After stirring evenly, the mixture is heated to 60-80℃ and kept at this temperature for 10-20 min under stirring. Then, a mixed gas of NH3 and CO2 is introduced into the mixture for reaction, and the reaction time is 3-5 h. The flow rate of the mixed gas is 0.5-2 mL / min, and the volume ratio of NH3 to CO2 in the mixed gas is 1:1. After the reaction is completed, the obtained solid material is filtered, washed with water, and washed with alcohol in sequence. The obtained solid material is then added to a dopamine hydrochloride solution and reacted at room temperature under stirring for 2-3 h. Finally, it is spray-dried to obtain the intermediate layer filler particles.

[0053] Furthermore, the preparation method of the dopamine hydrochloride solution is as follows: First, prepare an aqueous solution of dopamine hydrochloride with a concentration of 1-5%, then add an appropriate amount of Tris buffer to the aqueous solution of dopamine hydrochloride and adjust the pH of the aqueous solution of dopamine hydrochloride to 7-9, thereby obtaining the dopamine hydrochloride solution.

[0054] Furthermore, the amount of dopamine hydrochloride solution used is 5 to 10 times the weight of the calcium chloride.

[0055] Furthermore, the present invention also provides a method for preparing a plain-colored decorative base paper, the method being used to prepare the aforementioned plain-colored decorative base paper, the method comprising the following steps:

[0056] S1, Preparation of surface slurry: The oven-dried pulp boards of softwood pulp, hardwood pulp and kapok pulp are crushed separately according to the weight ratio, mixed and soaked in an alkaline solution with a concentration of 3-5% for 3-5 days. Then, they are rinsed with water until neutral and dried to a moisture content of 40-50%. The dried plant fibers and an appropriate amount of swelling agent are then placed in a microwave device and microwaved for 1-2 minutes at a frequency of 1000-2000MHz and a power of 300-500W. After microwave treatment, the pulp is beaten to obtain a mixed slurry. An appropriate amount of surface filler particles are added to the mixed slurry and stirred to mix evenly to obtain the surface slurry.

[0057] S2, Preparation of intermediate layer slurry: Take an appropriate amount of oven-dry cotton fiber pulp board and core-sheath polyester fiber according to the weight ratio. Then, break the oven-dry cotton fiber pulp board into pulp and beat it to obtain cotton pulp slurry. Then, mix the core-sheath polyester fiber with an appropriate amount of water to prepare a core-sheath polyester fiber suspension with a concentration of 0.5-1%. Then, mix the cotton pulp slurry and the core-sheath polyester fiber suspension, add intermediate layer filler particles, and stir evenly to obtain intermediate layer slurry.

[0058] S3, Preparation of plain decorative base paper: On a slanted wire paper machine or long wire paper machine with three independent flow channels, the surface slurry obtained in step S1 is used as the upper slurry and the lower slurry, and the intermediate slurry obtained in step S2 is used as the intermediate slurry. The paper is formed simultaneously and then dried at 150-180°C. After that, the surface of the dried paper is smoothed by hot press rolls, wherein the temperature of the hot press rolls is 50-80°C.

[0059] As some embodiments of the present invention, in step S1, the alkaline solution is an aqueous solution of sodium hydroxide.

[0060] Preferably, in step S1, the expanding agent is one or more of ammonium bicarbonate, sodium bicarbonate, and sodium dodecylbenzene sulfonate.

[0061] Furthermore, in step S1, the method of adding the bulking agent is as follows: first, the bulking agent is dissolved in water to prepare a bulking agent solution with a concentration of 5-20%, then the bulking agent solution is sprayed onto the fiber according to a bulking agent to fiber weight ratio of 3-8:100, and then placed in a microwave device for microwave treatment.

[0062] Furthermore, in step S1, the beating degree of the mixed slurry is 30-40°SR.

[0063] Furthermore, in step S1, the pulping concentration of the mixed slurry is 10-25%.

[0064] Furthermore, in step S1, the amount of surface filler particles added to the mixed slurry is 40-50% of the total weight of the surface layer oven-dry slurry board.

[0065] Furthermore, in step S2, the core-sheath type polyester fiber has a length of 3-7 mm and a fineness of 0.1-1 dtex.

[0066] Furthermore, in step S2, the beating degree of the cotton fiber is 25-35°SR.

[0067] Furthermore, in step S2, the pulping concentration of the cotton fibers is 10-20%.

[0068] Furthermore, in step S2, the amount of the intermediate layer filler particles added is 60-80% of the total weight of the oven-dry pulp of cotton fibers and the core-sheath type polyester fibers.

[0069] Furthermore, in steps S1 and S2, 2-5% wet strength agent and 1-3% dispersant, accounting for the total weight of the fiber, may be added to the surface slurry or intermediate slurry.

[0070] As some embodiments of the present invention, the wet strength agent is selected from one or more of urea-formaldehyde resin, polyamide-epoxychloropropane resin, melamine-formaldehyde resin, etc.

[0071] As some embodiments of the present invention, the dispersant is selected from one or more of polyethylene oxide, anionic polyacrylamide, HT5020, HT5040, etc.

[0072] Furthermore, in step S3, the on-line concentrations of the upper slurry, lower slurry, and intermediate slurry are 0.1–0.5%, 0.1–0.5%, and 0.2–0.5%, respectively.

[0073] The following specific embodiments illustrate the plain decorative base paper and its preparation method according to the present invention:

[0074] Example 1

[0075] Preparation of intermediate layer filler particles:

[0076] At room temperature, calcium chloride was first dissolved in an appropriate amount of water to prepare a calcium chloride solution with a concentration of 0.2 mol / L. Then, acid was added to adjust the pH of the calcium chloride solution to 4. Next, dextrin was added to the obtained calcium chloride solution with stirring at a concentration of 0.18 mol / L. After stirring evenly, the mixture was heated to 65°C and kept at this temperature with stirring for 20 min. Then, a mixture of NH3 and CO2 gas was introduced into the mixture for reaction for 4 h. The flow rate of the mixed gas was 1 mL / min, and the volume ratio of NH3 to CO2 in the mixed gas was 1:1. After the reaction was completed, the obtained solid material was filtered, washed with water, and washed with alcohol. The obtained solid material was then added to a dopamine hydrochloride solution, with the amount of dopamine hydrochloride solution being 6 times the weight of calcium chloride. After stirring at room temperature for 2 h, the mixture was spray-dried to obtain intermediate layer filler particles—hemispherical calcium carbonate particles with an average particle size of 0.3 mm.

[0077] Example 2

[0078] Preparation of plain decorative base paper:

[0079] S1, Preparation of surface slurry: Take 20 parts by weight of softwood pulp, 80 parts by weight of hardwood pulp and 30 parts by weight of kapok pulp, respectively, and pulp them separately. Mix them and soak them in a 3% alkaline solution for 5 days. Then rinse them with water until neutral and dry them to a moisture content of 43%. Then place the dried plant fibers and 5% by weight of the fiber in the surface slurry, ammonium bicarbonate, in a microwave device and microwave treat them for 2 minutes at a frequency of 1000MHz and a power of 300W. After microwave treatment, beat the mixture to obtain a mixed slurry. The beating concentration of the mixed slurry is 10% and the beating degree is 40°SR. Add 50% by weight of the total weight of the surface dry pulp board, 0.2μm titanium dioxide as surface filler particles, and stir to mix evenly to obtain the surface slurry.

[0080] S2, Preparation of intermediate layer slurry: Take 50 parts by weight of core-sheath polyester fiber and 50 parts by weight of cotton fiber, then break the oven-dry pulp board of cotton fiber into pulp, and then beat it to obtain cotton pulp slurry, wherein the beating concentration of cotton pulp is 20% and the beating degree is 25°SR; then mix core-sheath polyester fiber with an appropriate amount of water to prepare a core-sheath polyester fiber suspension with a concentration of 0.5%; then mix the cotton pulp slurry and the core-sheath polyester fiber suspension, and add intermediate layer filler particles accounting for 80% of the total weight of the oven-dry pulp board of cotton fiber and core-sheath polyester fiber, wherein the intermediate layer filler particles are the intermediate layer filler particles prepared in Example 1 above; after stirring evenly, the intermediate layer slurry is obtained.

[0081] S3, Preparation of plain decorative base paper: On a slanted wire paper machine or long wire paper machine with three independent flow channels, the surface slurry obtained in step S1 is used as the upper slurry and the lower slurry, and the intermediate slurry obtained in step S2 is used as the intermediate slurry. The paper is formed simultaneously and then dried at 150°C. After that, the surface of the dried paper is smoothed by hot press rolls, wherein the temperature of the hot press rolls is 80°C.

[0082] Example 3

[0083] Preparation of plain decorative base paper:

[0084] S1, Preparation of surface slurry: Take 25 parts by weight of softwood pulp, 60 parts by weight of hardwood pulp and 25 parts by weight of kapok pulp, respectively, and break them into pulp. Mix them and soak them in a 5% alkaline solution for 3 days. Then rinse them with water until neutral and dry them to a moisture content of 50%. Then place the dried plant fibers and 3% by weight of the fiber in the surface slurry, ammonium bicarbonate, in a microwave device and microwave treat them for 1 minute at a frequency of 2000MHz and a power of 500W. After microwave treatment, beat the pulp to obtain a mixed slurry. The beating concentration of the mixed slurry is 25% and the beating degree is 30SR. Add 40% by weight of the total weight of the surface dry pulp board, 0.2μm titanium dioxide as surface filler particles, as well as 0.2μm by weight, to the mixed slurry. Stir to mix evenly to obtain the surface slurry.

[0085] S2, Preparation of intermediate layer slurry: Take 40 parts by weight of core-sheath polyester fiber and 60 parts by weight of cotton fiber, then break the oven-dry pulp board of cotton fiber into pulp, and then beat it to obtain cotton pulp slurry, wherein the beating concentration of cotton pulp is 10% and the beating degree is 25°SR; then mix core-sheath polyester fiber with an appropriate amount of water to prepare a core-sheath polyester fiber suspension with a concentration of 1%; then mix the cotton pulp slurry and the core-sheath polyester fiber suspension, and add intermediate layer filler particles accounting for 60% of the total weight of the oven-dry pulp board of cotton fiber and core-sheath polyester fiber, wherein the intermediate layer filler particles are the intermediate layer filler particles prepared in Example 1 above; after stirring evenly, the intermediate layer slurry is obtained.

[0086] S3, Preparation of plain decorative base paper: On a slanted wire paper machine or long wire paper machine with three independent flow channels, the surface slurry obtained in step S1 is used as the upper slurry and the lower slurry, and the intermediate slurry obtained in step S2 is used as the intermediate slurry. The paper is formed simultaneously and then dried at 180°C. After that, the surface of the dried paper is finished by using hot press rolls, wherein the temperature of the hot press rolls is 50°C.

[0087] Example 4

[0088] Preparation of plain decorative base paper:

[0089] S1, Preparation of surface slurry: Take 30 parts by weight of softwood pulp, 70 parts by weight of hardwood pulp and 20 parts by weight of kapok pulp, respectively, and pulp them separately. Mix them and soak them in a 4% alkaline solution for 4 days. Then rinse them with water until neutral and dry them to a moisture content of 40.6%. Then place the dried plant fibers and 8% by weight of the fiber in the surface slurry, ammonium bicarbonate, as a swelling agent, in a microwave device and microwave treat them for 1.5 minutes at a frequency of 1500MHz and a power of 400W. After microwave treatment, beat the mixture to obtain a mixed slurry. The beating concentration of the mixed slurry is 20% and the beating degree is 35°SR. Add 45% by weight of titanium dioxide with a particle size of 0.2um as surface filler particles to the mixed slurry as a total weight of the dry pulp board for the surface layer. Stir to mix evenly to obtain the surface slurry.

[0090] S2, Preparation of intermediate layer slurry: Take 60 parts by weight of core-sheath polyester fiber and 40 parts by weight of cotton fiber. Then, break the oven-dry pulp board of cotton fiber into pulp and beat it to obtain cotton pulp slurry. The beating concentration of cotton pulp is 16% and the beating degree is 30°SR. Then, mix core-sheath polyester fiber with an appropriate amount of water to prepare a core-sheath polyester fiber suspension with a concentration of 0.8%. Then, mix the cotton pulp slurry and the core-sheath polyester fiber suspension, and add intermediate layer filler particles accounting for 70% of the total weight of the oven-dry pulp board of cotton fiber and core-sheath polyester fiber. The intermediate layer filler particles are the intermediate layer filler particles prepared in Example 1 above. After stirring evenly, the intermediate layer slurry is obtained.

[0091] S3, Preparation of plain decorative base paper: On a slanted wire paper machine or long wire paper machine with three independent flow channels, the surface slurry obtained in step S1 is used as the upper slurry and the lower slurry, and the intermediate slurry obtained in step S2 is used as the intermediate slurry. The paper is formed simultaneously and then dried at 170°C. After that, the surface of the dried paper is smoothed by hot press rolls, wherein the temperature of the hot press rolls is 60°C.

[0092] Comparative Example 1

[0093] Preparation of plain decorative base paper:

[0094] The only difference between Comparative Example 1 and Example 4 above is that in step S1, after each pulp board is broken into pulp, it is not soaked in alkaline solution and microwaved, but directly pulped to obtain a mixed pulp. The rest is the same as Example 4 above, and will not be repeated here.

[0095] Comparative Example 2

[0096] Preparation of plain decorative base paper:

[0097] The only difference between Comparative Example 2 and Example 4 above is that in step S2, ordinary polyester fiber (melting point above 230°C) is used instead of core-sheath polyester fiber. All other aspects are the same as in Example 4 above, and will not be repeated here.

[0098] Comparative Example 3

[0099] The only difference between Comparative Example 3 and Example 4 above is that, in step S2, spherical calcium carbonate particles with an average particle size of 0.3 mm are used as intermediate layer filler particles. All other aspects are the same as in Example 4 above, and will not be repeated here.

[0100] Comparative Example 4

[0101] The only difference between Comparative Example 4 and Example 4 above is that in step S3, the wet paper sheet formed is dried at 100°C, and then the surface of the dried paper is shaped using a hot press roller, wherein the temperature of the hot press roller is 60°C. The rest is the same as in Example 4 above, and will not be repeated here.

[0102] Performance testing:

[0103] The performance of the plain decorative base paper prepared in Examples 2-4 and Comparative Examples 1-4 was tested respectively. The test results are shown in Table 1 below:

[0104] Table 1. Performance Test Results of Decorative Base Paper

[0105]

[0106] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A base decorative paper, characterized in that, It is composed of an intermediate layer (2) and a surface layer (1) located on both sides of the upper and lower, wherein the surface layer (1) includes surface layer fiber (101) and filler particles (102) filled between the surface layer fiber (101), the intermediate layer (2) includes intermediate layer fiber (201) and intermediate layer filler particles (202) filled between the intermediate layer fiber (201), the intermediate layer filler particles (202) are semispherical; The surface layer fiber (101) comprises 20-30 parts by weight of needle wood fiber, 60-80 parts by weight of broadleaf wood fiber and 20-30 parts by weight of kapok fiber; The intermediate layer fiber (201) comprises 40-60 parts by weight of skin-core polyester fiber and 40-60 parts by weight of cotton fiber, the skin layer of the skin-core polyester fiber is low melting point polyester with a melting point of 100-150℃, the core layer is polyester with a melting point of 250-270℃, the skin layer of the skin-core polyester fiber accounts for 20-40% of the total weight of the fiber, and the core layer accounts for 60-80% of the total weight of the fiber; The intermediate layer filler particles (202) include small particle fillers with a particle size of 50-100 and large particle fillers with a particle size of 300-500um. The preparation method of the plain decorative base paper comprises the following steps: S1, preparing surface layer slurry: the absolute dry pulp boards of needle wood pulp, broadleaf wood pulp and kapok pulp are respectively crushed after being mixed and soaked in an alkali solution with a concentration of 3-5% for 3-5 days, then washed to neutral with water and dried to a moisture content of 40-50%, then the dried plant fibers and appropriate amount of bulking agent are placed in a microwave device for microwave treatment at a frequency of 1000-2000MHz and a power of 300-500W for 1-2min, then the mixed pulp is obtained after beating, and then the surface layer filler particles are added to the mixed pulp, stirred to mix uniformly, and then the surface layer slurry is obtained; S2, preparing intermediate layer slurry: the absolute dry pulp boards of cotton fiber and skin-core polyester fiber are taken according to the weight ratio, then the cotton fiber is crushed and beaten to obtain cotton pulp slurry; then the skin-core polyester fiber is mixed with appropriate amount of water to prepare a skin-core polyester fiber suspension with a concentration of 0.5-1%, then the cotton pulp slurry and the skin-core polyester fiber suspension are mixed, and the intermediate layer filler particles are added, stirred uniformly, and then the intermediate layer slurry is obtained; S3, preparation of plain decorative base paper: on a inclined screen paper machine or a long net paper machine with three independent flow channels, the surface layer slurry obtained in step S1 is used as the upper layer slurry and the lower layer slurry, and the intermediate layer slurry obtained in step S2 is used as the intermediate layer slurry, and then the three layers are simultaneously formed by beating, and then dried at 150-180℃, and then the surface of the dried paper is treated by hot calendering, wherein the temperature of the hot calendering is 50-80℃.

2. The base decorative base paper according to claim 1, characterized in that, The thickness of the intermediate layer (2) is 0.4-0.6mm, and the thickness of the surface layer (1) is 0.2-0.3mm.

3. The base decorative paper according to claim 1 or 2, characterized in that, The radius of the intermediate layer filler particles (202) is 60-80% of the thickness of the intermediate layer (2).

4. The base decorative base paper according to claim 1, characterized in that, The surface layer filler particles (102) are one or more of spherical, spindle-shaped, dumbbell-shaped, and acicular titanium dioxide particles.

5. The base decorative paper according to claim 1 or 2, characterized in that, The average particle size of the surface layer filler particles (102) is 0.1-0.3 μm.

6. The base decorative base paper according to claim 1, characterized in that, The intermediate layer filler particles (202) are semi-spherical calcium carbonate particles.

7. The base decorative paper according to claim 1 or 6, characterized in that, The intermediate layer filler particles (202) are prepared as follows: at room temperature, first, calcium chloride is dissolved in an appropriate amount of water to prepare a calcium chloride solution with a concentration of 0.1-0.3 mol / L, and then acid is added to adjust the pH of the calcium chloride solution to 3-5; then, while stirring, dextrin is added to the resulting calcium chloride solution, the amount of dextrin added being 0.1-0.3 mol / L, after stirring to homogeneity, the mixture is heated to 60-80°C, and while stirring, the mixture is maintained at this temperature for 10-20 min; then, a mixed gas of NH3 and CO2 is bubbled into the mixture to react, the reaction time being 3-5 h, wherein the flow rate of the mixed gas is 0.5-2 mL / min, and in the mixed gas, the volume ratio of NH3 to CO2 is 1:1; after the reaction is complete, the resulting solid material is sequentially filtered, washed with water, and washed with alcohol, and then the resulting solid material is added to a dopamine hydrochloride solution, after stirring at room temperature for 2-3 h, spray drying is performed to obtain the intermediate layer filler particles.

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