A method for preparing large-size flame-retardant / fire-resistant "Xuan paper"

Abstract

The application relates to a preparation method of large-size flame-retardant / fire-resistant 'Xuan paper', which comprises the following steps: (1) purifying inorganic fibers through a conical deslagging device of a deslagging equipment to obtain purified inorganic fibers; (2) uniformly mixing organic fiber slurry and the purified inorganic fibers to obtain composite slurry; (3) filtering and forming the composite slurry into a wet paper sheet through active suction of the slurry in a net part, and then performing pressing and drying to obtain the large-size flame-retardant / fire-resistant 'Xuan paper'.

Description

Technical Field

[0001] This invention relates to the preparation of large-size flame-retardant / fire-resistant "Xuan paper" using inorganic and organic fiber composites or composites of one or more inorganic fibers as raw materials, and belongs to the technical field of composite fiber flame-retardant paper base material preparation process. Background Technology

[0002] In 2014, a team led by Professor Zhu Yingjie at the Shanghai Institute of Ceramics, Chinese Academy of Sciences, synthesized hydroxyapatite (HAP) ultralong nanowires for the first time and proposed using HAP ultralong nanowires as a building material for inorganic refractory paper, thus inventing inorganic refractory paper. In recent years, Professor Zhu's team has made significant breakthroughs in the exploration of HAP ultralong nanowire mass production technology and the application research of inorganic refractory paper, and is currently focusing on promoting the industrialization of inorganic refractory paper. The inorganic nanomaterial HAP ultralong nanowires, as a raw material for refractory paper, have expanded the raw material and application fields of composite fiber flame-retardant paper-based special materials. Recently, Professor Zhu's research team has also made significant progress in synthesizing micron-sized calcium phosphate fibers as a building material and application field for inorganic flame-retardant paper. Summary of the Invention

[0003] Based on this, the present invention provides a method for preparing large-size flame-retardant / fire-resistant "Xuan paper", comprising:

[0004] (1) The inorganic fiber is purified by the conical slag remover of the slag removal equipment to obtain the purified inorganic fiber;

[0005] (2) After the organic fiber slurry and the purified inorganic fiber are mixed evenly, a mixed slurry is obtained;

[0006] (3) The mixed pulp is filtered and formed into a wet paper sheet by active suction at the wire section. After pressing and drying, large-size flame-retardant / fire-resistant "Xuan paper" is obtained.

[0007] Preferably, the organic fibers include micron-sized plant fibers, plant nanocellulose, bacterial cellulose, micron-sized aramid fibers, aramid nanofibers, organic polymer fibers, etc.

[0008] Preferably, the inorganic fibers include at least one of hydroxyapatite ultralong nanowires, calcium phosphate fibers, aluminum silicate fibers, magnesium silicate fibers, alumina fibers, and glass fibers.

[0009] Preferably, the freeness of the organic fiber pulp is >20°S.

[0010] Preferably, organic fibers (excluding plant nanocellulose and nanobacterial cellulose) are placed in a refiner for refining to obtain an organic fiber slurry; the parameters of the refiner include: slurry concentration of 0.1–3 wt.%, and refiner blade distance ≤ 5 mm. The content of the slurry concentration of 0.1–3 wt.% is the concentration of the obtained organic fiber slurry of 0.1–3 wt.%. Alternatively, organic fibers are dispersed in a solvent, wherein the solvent is water, to obtain an organic fiber slurry, and the content of the obtained organic fiber slurry is 0.05–40 wt.%.

[0011] Preferably, the parameters of the conical slag remover include: 1 to 5 slag removal stages, until the amount of slag balls after slag removal is less than 5 wt.%, or there are no visible particles on the finished paper sheets.

[0012] Preferably, the mass ratio of organic fiber to purified inorganic fiber in the organic fiber slurry is (0-10):(0-1).

[0013] Preferably, in the active suction method, the drive shaft drives the wire section, passing the pulp in the headbox. The wire section, through the suction force of the vacuum system, draws the pulp onto the filter screen, forming a wet paper sheet. The parameters of the active suction method include: a vacuum degree of ≤0.1MPa for the active suction vacuum system; an operating speed of 0–5m / min for the active suction wire section, not zero; ensuring the operating speed of the wet paper sheet is 0–5m / min and not zero during the filtration and forming process; a press pressure ≤0.6MPa; and a drying temperature of 50–300℃ and a drying time of 3–30min.

[0014] Preferably, the mixed slurry further includes an additive; the additive is selected from at least one of dry strength agents, wet strength agents, waterproofing agents, oil-resistant agents, surface sizing agents, and inorganic adhesives.

[0015] Preferably, retention aids, defoamers, bactericides, etc. can be added to the web forming slurry (not necessarily, depending on the actual situation).

[0016] On the other hand, the present invention provides a large-size flame-retardant / fire-resistant "Xuan paper" prepared according to the above preparation method, characterized in that the size of the large-size flame-retardant / fire-resistant "Xuan paper" is at least A3 size, and the typical size is at least 70cm×140cm.

[0017] In another aspect, the present invention provides an application of the above-mentioned large-size flame-retardant / fire-resistant "Xuan paper" in the fields of electrical insulation, heat insulation, high temperature resistance, flame retardancy, and calligraphy and painting paper. Attached Figure Description

[0018] Figure 1A photograph of a large-size flame-retardant / fire-resistant "Xuan paper" prepared for this invention (the paper size in the picture is 75cm × 140cm).

[0019] Figure 2 A photograph of a large-size flame-retardant / fire-resistant "Xuan paper" prepared for this invention (the paper size in the picture is 75cm × 140cm). Detailed Implementation

[0020] The present invention will be further illustrated by the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention.

[0021] This disclosure describes a process for preparing large-size flame-retardant / fire-resistant "Xuan paper" using processes such as filtration molding, pressing, and drying, which differs from traditional papermaking processes. This invention is the first to apply the traditional pulp molding method to the molding process of large-size flame-retardant / fire-resistant "Xuan paper," where the pulp is actively sucked onto the mesh, allowing for simple quantitative control of the large-size flame-retardant / fire-resistant "Xuan paper."

[0022] In this invention, the large-size flame-retardant / fire-resistant "Xuan paper" base material is prepared by combining inorganic fibers (one or more of HAP ultralong nanowires, HAP nanotubes, calcium phosphate fibers, magnesium silicate fibers, aluminum silicate fibers, alumina fibers, glass fibers, carbon fibers, etc.) with organic fibers (one or more of micron-sized aramid fibers, aramid nanofibers, plant fibers, plant nanocellulose, bacterial cellulose, organic synthetic fibers, etc.). The organic fibers can have a diameter of 10 nm to 50 μm and a length of 100 μm to 12 mm. The inorganic fibers can have a diameter of 10 nm to 50 μm and a length of 100 μm to 12 μm.

[0023] In existing inorganic fiber preparation processes, traditional inorganic fiber raw materials typically contain a large number of slag balls, affecting paper uniformity and air permeability. Therefore, this invention purifies the inorganic fibers using a conical slag remover to remove non-fiber slag balls and other impurities.

[0024] In this invention, organic fibers are subjected to a pulping process using a pulper to achieve a certain degree of freeness (freeness greater than 20°S), thereby refining the organic fibers, increasing the contact points and contact area between pulp fibers, and thus improving the mechanical properties of the paper.

[0025] In this invention, the water filtration molding step adopts a method similar to pulp molding, and uses an active pulp suction method to solve the problem of difficult pulp filtration.

[0026] According to the purpose and performance requirements of large-size flame-retardant / fire-resistant "Xuan paper", functional additives such as dry strength agents, wet strength agents, waterproof agents, oil-resistant agents, surface sizing agents, and inorganic adhesives can be added to make the paper have the performance to meet the needs of a certain field.

[0027] In this invention, papermaking process additives, such as retention aids, defoamers, and bactericides, can be added to improve the papermaking performance based on the wet-end chemical properties and processes of the papermaking process in actual production.

[0028] The large-size flame-retardant / fire-resistant "Xuan paper" obtained in this invention can be applied to special fields such as electrical insulation, heat insulation, high temperature resistance, flame retardancy, and calligraphy and painting paper.

[0029] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are all within the scope of protection of the present invention. The specific process parameters in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below. Unless otherwise specified, the parameters for the active suction method in the following examples include: active suction in a vacuum system with a vacuum degree ≤ 0.1 MPa; the wire running speed during active suction is less than 5 m / min; the running speed of the wet paper sheet is maintained at 1 m / min during the dewatering and forming process; and the pressing pressure is 0.4 MPa.

[0030] The drying temperature is 50–300℃, and the drying time is 3–30 min.

[0031] Example 1:

[0032] First, aramid fibers are added to a refiner for refining (slurry concentration 2 wt.%, refiner blade distance range 3 mm) to achieve a freeness >20°S. Calcium phosphate fibers are then descaled in a conical descaling device (refinement stages 2). 80g of aramid fibers are dispersed in water, and then 20g of dried calcium phosphate fibers (organic fiber:inorganic fiber = 4:1) are added and stirred evenly. The prepared slurry is then filtered and formed into a wet paper sheet using an active suction method on the wire section. The wet paper sheet is then pressed and dried to form large-size flame-retardant / fire-resistant "Xuan paper".

[0033] Example 2:

[0034] The calcium phosphate fiber is descaled in a conical descaling device (two descaling stages). 20g of nanocellulose is dispersed in water (nanocellulose concentration 0.1wt.%), and 80g of dried calcium phosphate fiber (organic fiber:inorganic fiber = 1:4) is added and stirred evenly. The prepared pulp is filtered and formed into a wet paper sheet by active suction at the wire section. The wet paper sheet is then pressed and dried to form a large-size flame-retardant / fire-resistant "Xuan paper".

[0035] Example 3:

[0036] HAP ultra-long nanowires are descaled in a conical descaling device (two descaling stages). 30g of bacterial cellulose is dispersed in water, and 80g of HAP ultra-long nanowires (organic fiber: inorganic fiber = 3 / 8:1) are added and stirred until homogeneous to obtain a pulp. The prepared pulp is filtered and formed into a wet paper sheet by active suction at the wire section. The wet paper sheet is then pressed and dried to form large-size flame-retardant / fire-resistant "Xuan paper".

Claims

1. A process for the preparation of large size flame retardant / fire resistant "Xuan paper" characterized in that, The application relates to a large-size fire-retardant / fire-resistant "Xuan paper", which comprises the following steps: (1) purifying inorganic fibers through a slag removal equipment conical slag remover to obtain purified inorganic fibers; (2) uniformly mixing organic fiber pulp and the purified inorganic fibers to obtain a composite pulp; The organic fibers in the organic fiber pulp comprise at least one of bacterial cellulose, micron-level aramid fibers and aramid nanofibers; the mass ratio of the organic fibers in the organic fiber pulp to the purified inorganic fibers is 4:1-1:4; putting the organic fiber into a grinder to obtain an organic fiber pulp, the beating degree of the organic fiber pulp being >20 o S, wherein the parameters of the grinder include: pulp concentration being 0.1-3 wt.%, and the range of the grinder knife distance being ≤5 mm; or dispersing the organic fiber in solvent water to obtain an organic fiber pulp, the content of the obtained organic fiber pulp being 0.05-40 wt.%; (3) forming a wet paper sheet through dewatering and forming of the composite pulp in a wire section in an active suction pulp mode, and then performing pressing and drying to obtain the large-size fire-retardant / fire-resistant "Xuan paper"; the large-size fire-retardant / fire-resistant "Xuan paper" has a size of at least A3 size; The active suction pulp mode comprises: a transmission shaft drives the wire section to pass through the pulp in a headbox, the wire section is sucked to a filter screen through the suction force of a vacuum system, and the wet paper sheet is formed on the filter screen; the parameters of the active suction pulp mode comprise: the active suction pulp is carried out in a vacuum system with a vacuum degree of less than or equal to 0.1 MPa, the running speed of the wire section is less than or equal to 5 m / min during the active suction pulp, and the running speed of the wet paper sheet is less than or equal to 5 m / min during the dewatering and forming process.

2. The production method according to claim 1, characterized by, The inorganic fibers comprise at least one of hydroxyapatite super-long nanowires, calcium phosphate fibers, aluminum silicate fibers, magnesium silicate fibers, aluminum oxide fibers and glass fibers.

3. The production method according to claim 1, characterized by, The parameters of the slag removal equipment conical slag remover comprise: the slag removal stages are 1-5 stages, until the amount of slag balls after slag removal is less than 5 wt.%, or there are no visible particulate matters on the paper sheet.

4. The production method according to claim 1, characterized by, The pressure of the pressing is less than or equal to 0.6 MPa; The temperature of the drying is 50-300 DEG C, and the drying time is 3-30 min.

5. The preparation method according to claim 1, characterized in that, The composite pulp further comprises an auxiliary agent; the auxiliary agent is selected from at least one of dry strength agents, wet strength agents, water-proof agents, oil-proof agents, surface sizing agents and inorganic adhesives.

6. The method of claim 1, wherein, At least one of a retention aid, a defoaming agent and a bactericide is added to the composite pulp on the wire.

7. A large size flame / fire retardant "Xuan paper" prepared according to the preparation method of any one of claims 1-6, characterized in that, The large-size fire-retardant / fire-resistant "Xuan paper" has a size of at least A3 size.

8. The large size flame / fire retardant "rice paper" according to claim 7, characterized by, The large-size fire-retardant / fire-resistant "Xuan paper" has a size of at least 70 cm*140 cm.

9. Application of the large-size fire-retardant / fire-resistant "Xuan paper" in the field of electrical insulation, the field of heat insulation, the field of high-temperature resistance, the field of fire retardation and the field of painting paper.

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