Alkali-free glass fiber paper, its preparation method and application

Abstract

The application relates to an alkali-free glass fiber paper and a preparation method and application thereof. The preparation method comprises the following steps: adding alkali-free glass fiber cotton into deionized water to be fully dispersed through mechanical dissociation to obtain a dispersed alkali-free glass fiber cotton slurry; repeatedly dispersing and treating and mechanically stirring and circulating the obtained alkali-free glass fiber cotton slurry; performing a papermaking type treatment on the obtained slurry to obtain a formed paper; simultaneously performing vacuum suction treatment and heating stamping treatment on the obtained formed paper, compressing the internal structure of the paper to densify the same, and obtaining the alkali-free glass fiber paper. Through the combined process of "mechanical dissociation-ultrasonic and mechanical stirring and circulating dispersion-pulping and blank forming-vacuum suction-heating stamping", the alkali-free glass fiber paper without organic additives and inorganic impurities, which is dense in structure and can be stably used at a high temperature of 700 DEG C, is prepared.

Description

Technical Field

[0001] This invention belongs to the technical field of high-temperature protective functional materials, specifically relating to an alkali-free glass fiber paper, its preparation method, and its application. Background Technology

[0002] In cutting-edge industrial fields such as aerospace, semiconductor manufacturing, and high-end industrial kilns, core precision equipment and components (such as sensors in aircraft engine nacelles and temperature measuring elements in industrial kilns) are constantly exposed to high-temperature environments of around 700°C and are extremely sensitive to impurities in the working environment. If such equipment is contaminated by volatile gases or liquid deposits at high temperatures, it can easily lead to performance degradation, loss of accuracy, or even functional failure.

[0003] Currently, to achieve good molding stability, traditional glass fiber paper commonly incorporates organic adhesives (such as phenolic resins and epoxy resins) or inorganic binders (such as silica sol and alumina sol) during the manufacturing process. However, these additives have significant drawbacks at high temperatures: organic adhesives undergo thermal decomposition and carbonization above 400℃, releasing volatile organic compounds and causing air pollution; while inorganic binders, although able to withstand higher temperatures, often leave residual sodium, calcium, and other metal ions or amorphous inorganic phases in the fiber structure, which migrate to the surface of the protected component at high temperatures, causing contamination. However, without adhesives, relying solely on the internal fiber interweaving results in insufficient bonding and a loose structure. The fibers are only bonded by physical overlap and weak van der Waals forces, leading to a tensile strength below 0.01 MPa. At high temperatures, this structural relaxation easily causes a loss of protective effectiveness, making long-term stable use in environments up to 700℃ difficult.

[0004] Therefore, achieving high-density entanglement and structural stability between glass fibers through green, low-temperature physical methods, while avoiding the introduction of organic / inorganic additives, and simultaneously ensuring the material's tensile strength, thermal stability, and thermal shock resistance at 700℃, has become crucial to overcoming current technological bottlenecks. Against this backdrop, developing an alkali-free glass fiber paper that is completely independent of organic additives and inorganic binders, possessing high structural density, excellent high-temperature dimensional stability, and good mechanical strength, has significant engineering and technological value and broad application prospects for addressing the long-term reliable protection needs of precision equipment in high-temperature sensitive environments. Summary of the Invention

[0005] In view of this, the main objective of this invention is to provide an alkali-free glass fiber paper, its preparation method, and its application. The problem to be solved is to use a combined process of "mechanical dissociation - ultrasonic and mechanical stirring circulation dispersion - papermaking - vacuum suction - heating and stamping" to produce alkali-free glass fiber cotton as a single raw material. Vacuum suction is used to remove air and moisture from the inside of the paper blank, and then heating and stamping are used to further compress the gaps between fibers. This allows the glass fibers to achieve dense shaping solely through physical winding and van der Waals forces. Finally, an alkali-free glass fiber paper with no organic additives, no inorganic impurities, dense structure, and stable use at 700°C is prepared, meeting the precision protection requirements of aerospace, industrial kilns, and other fields that are sensitive to high-temperature impurities.

[0006] The objective of this invention and the technical problem it solves are achieved through the following technical solution. This invention proposes a method for preparing alkali-free glass fiber paper, comprising the following steps: 1) Add alkali-free fiberglass wool to deionized water and disperse it fully through mechanical dissociation to obtain a dispersed alkali-free fiberglass wool slurry; 2) The alkali-free fiberglass slurry obtained in step 1) is subjected to repeated dispersion and mechanical stirring circulation treatment; 3) The slurry obtained in step 2) is subjected to a molding process to obtain the finished paper; 4) The formed paper obtained in step 3) is simultaneously subjected to vacuum suction treatment and heating and pressing treatment to compress the internal structure of the paper and make it dense, thereby obtaining the alkali-free glass fiber paper.

[0007] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0008] Preferably, in the aforementioned method for preparing alkali-free glass fiber paper, in step 1), the filament diameter of the alkali-free glass fiber cotton is 0.6 micrometers.

[0009] Preferably, in the aforementioned method for preparing alkali-free glass fiber paper, in step 1), the mechanical dissociation is carried out by high-speed shear stirring, with a stirring speed of 8000~10000 rpm and a dissociation time of 3~5 min; the monofilament dispersion rate of the alkali-free glass fiber cotton after dissociation is ≥90%.

[0010] Preferably, in the aforementioned method for preparing alkali-free glass fiber paper, in step 1), the mass ratio of deionized water to dispersed alkali-free glass fiber cotton is (250~270):1.

[0011] Preferably, in the aforementioned method for preparing alkali-free glass fiber paper, in step 2), the repeated dispersion treatment is performed 4 to 6 times; each dispersion treatment first uses ultrasonic-assisted ultrasonic power of 40 to 50 kHz and dispersion time of 10 to 15 min, and then stirs at a speed of 9000 to 12000 rpm for 2 to 4 min.

[0012] Preferably, in the aforementioned method for preparing alkali-free glass fiber paper, in step 3), the papermaking temperature of the papermaking molding process is 15~20℃, the papermaking vacuum degree is -0.4~-0.3MPa, and the thickness of the initial paper blank is 0.5~0.8mm.

[0013] Preferably, in the aforementioned method for preparing alkali-free glass fiber paper, in step 4), the vacuum degree of the vacuum suction treatment is -0.08 to -0.10 MPa; the temperature of the heating and stamping treatment is 120 to 150°C, the stamping pressure is 1.2 to 1.8 MPa, and the suction and stamping time is 60 to 80 min.

[0014] The objective of this invention and the technical problem it solves can also be achieved using the following technical solutions. This invention proposes an alkali-free glass fiber paper, which is prepared by the method described above.

[0015] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0016] Preferably, the aforementioned alkali-free fiberglass paper has a thickness of 0.18~0.22mm, a heat resistance temperature of 700℃, and conforms to the GB / T 5464-2010 standard for non-combustible materials; and releases no gas or liquid substances when heated to 700℃.

[0017] The objective of this invention and the technical problem it solves can also be achieved using the following technical solutions. This invention proposes the application of alkali-free glass fiber paper in high-temperature environments sensitive to impurities, wherein the temperature range of the high-temperature environment is room temperature to 700℃.

[0018] Preferably, the aforementioned alkali-free glass fiber paper is used in high-temperature environments sensitive to impurities, wherein the high-temperature environment includes the area around precision sensors in aerospace engine compartments and the protected area of ​​temperature measuring elements in industrial high-temperature kilns.

[0019] By employing the above technical solution, the alkali-free glass fiber paper, its preparation method, and its application provided by the present invention have at least the following advantages: This invention significantly compresses the internal voids of glass fiber paper by combining a vacuum condition with a pressure drying process, thereby improving structural density. This allows the fibers to achieve stable paper formation simply through entanglement, eliminating the need for inorganic / organic additives and preventing the introduction of non-glass impurities. This results in a morphologically stable glass fiber paper material. The obtained product possesses heat resistance of at least 700℃ and non-flammability, and does not release volatiles at high temperatures.

[0020] The alkali-free glass fiber paper prepared by this invention is suitable for high-temperature working environments sensitive to impurity content. It can be used for heat insulation and pressure protection of precision equipment and components, and has the characteristics of low cost and excellent protective effect.

[0021] This invention uses only alkali-free fiberglass wool throughout the entire process, without introducing any organic additives or inorganic impurities. It does not release gas or liquid when heated to 700℃, making it suitable for high-temperature environments in high-end manufacturing that are sensitive to impurities.

[0022] This invention utilizes a composite physical process of vacuum suction and heating stamping to fully compress the internal space of the fiberglass paper, resulting in tightly wound and shaped fibers. The finished product has a thickness ≥0.18mm, a tensile strength ≥2.0MPa, and a strength retention rate ≥85% after being kept at 700℃ for 24 hours. This effectively solves the technical problems of traditional glue-free fiberglass paper having a loose structure and being prone to relaxation at high temperatures.

[0023] This invention mainly uses conventional high-speed stirring, papermaking, and vacuum suction equipment, without the need for special modification or complex processes such as high-temperature sintering. The raw material is commonly used industrial alkali-free glass fiber cotton, and the production cost is estimated to be more than 40% lower than that of high-temperature glass fiber paper containing special binders, which is conducive to industrialization and promotion.

[0024] This invention addresses the environmental protection needs of high-temperature environments (700°C) and environments sensitive to impurities, filling a technological and market gap in the existing glass fiber paper for this high-end application.

[0025] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0026] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with preferred embodiments, provides a detailed explanation of the specific implementation methods, structures, features, and effects of an alkali-free glass fiber paper, its preparation method, and its application according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0027] Unless otherwise specified, all materials or reagents listed below are commercially available.

[0028] Some embodiments of the present invention provide a method for preparing alkali-free glass fiber paper, comprising the following steps: 1) Take alkali-free glass fiber cotton with a filament diameter of 0.6-0.8 micrometers, add deionized water, and use mechanical dissociation method to fully disperse it to obtain a dispersed state alkali-free glass fiber cotton slurry; when the filament diameter is below 0.6 micrometers, alkali-free glass fiber cotton cannot be formed (there is no finer material), and when the filament diameter is above 0.8 micrometers, the paper strength will decrease to 0.1 times that of the paper.

[0029] 2) Treat the alkali-free fiberglass slurry with ultrasonic dispersion and mechanical stirring circulation; 3) The pulp obtained in step 1) is shaped in a paper machine; 4) The formed paper is simultaneously subjected to vacuum suction and heat-pressing treatment to compress its internal structure and make it denser, resulting in alkali-free glass fiber paper with a thickness of approximately 0.2-0.3 mm. When the thickness is less than 0.2 mm, the paper strength will drop to one-third of its original strength; when it is greater than 0.3 mm, it will cause problems in some applications where thickness is a requirement.

[0030] In some optional embodiments, in step 1), the mechanical dissociation method is implemented using a high-speed shear mixer with a mixing speed of 8000~10000 rpm and a dissociation time of 3~5 min; after dissociation, the monofilament dispersion rate of the alkali-free glass fiber cotton is ≥90%. A speed below 8000 rpm or less than 3 min will result in uneven pulp, while a speed above 10000 rpm or greater than 5 min will cause the glass fiber to be shredded, making it difficult to form paper.

[0031] In some optional embodiments, in step 1), the mass ratio of the deionized water to the dispersed alkali-free fiberglass cotton is (250~270):1.

[0032] In some optional embodiments, in step 2), the number of repeated dispersion operations is 4 to 6 times. If the number of times is less than 4, the dispersion will be uneven, while if the number of times is more than 6, it will be a waste of time. Each dispersion is first assisted by ultrasound (ultrasound power 40 to 50 kHz, dispersion time 10 to 15 min, if the number of times is less than 10 min, the dispersion will be uneven, while if the number of times is more than 15 min, it will be a waste of time. Then, the stirring is carried out at a speed of 9000 to 12000 rpm for 2 to 4 min. If the stirring is less than 9000 rpm or less than 2 min, the stirring will be uneven, while if the stirring is more than 12000 rpm or more than 4 min, the mixture will be easily crushed.

[0033] In some optional embodiments, in step 3), the paper machine is a cylinder paper machine, the paper temperature is 15~20℃, the paper vacuum degree is -0.4~-0.3MPa, the paper will be broken when it is below -0.4MPa, and it will be uneven when it is above -0.3MPa; the thickness of the initial paper blank is 0.5~0.8mm.

[0034] In some optional embodiments, in step 4), the vacuum degree of the vacuum suction process is -0.08 to -0.10 MPa. If the vacuum degree is below -0.10 MPa, it will be too low and the paper will break. If it is too high, the drying time will be too long. The temperature of the heating and pressing process is 120 to 150°C. If the temperature is below 120°C, the drying time will be long and time will be wasted. If the temperature is above 150°C, it will lead to wasted electricity. The pressing pressure is 1.2 to 1.8 MPa. If the pressure is below 1.2 MPa, the paper will not clump together and the drying time will be slow. If the pressure is above 1.8 MPa, the paper will be crushed. The suction and pressing time is 60 to 80 minutes. If the time is less than 60 minutes, the paper will not be dried. If the time is greater than 80 minutes, it will lead to wasted electricity.

[0035] Some embodiments of the present invention also provide an alkali-free glass fiber paper, which is prepared by the above-described method.

[0036] In some optional embodiments, the alkali-free fiberglass paper has a thickness of 0.18~0.22mm, a heat resistance temperature of 700℃, and conforms to the GB / T 5464-2010 standard for non-combustible materials; when heated to 700℃, no gas or liquid substances are released (according to GB / T 6040-2002 infrared spectroscopy analysis, no volatile components are found).

[0037] Specifically, the properties of the alkali-free glass fiber paper are as follows: Pure composition: This paper is composed only of 0.6-micron alkali-free glass fiber, without any organic additives or inorganic impurities.

[0038] Mechanical properties: Thickness 0.18~0.22mm, tensile strength ≥0.25MPa (tested according to GB / T 12914-2018).

[0039] Heat resistance and non-combustibility: After being kept at 700℃ for 24 hours, the tensile strength retention rate is ≥85%, and there is no structural deformation; it meets the GB / T 5464-2010 standard for non-combustible materials (remaining length of burning ≥96%, no open flame, no molten dripping).

[0040] High-temperature cleanliness: When heated to 700℃, infrared spectroscopy analysis according to GB / T 6040-2002 shows no release of any volatile gases or liquids, meeting the stringent requirements of impurity-sensitive environments.

[0041] Some embodiments of the present invention also provide an application of alkali-free fiberglass paper, which is applied to high-temperature environments (temperature range from room temperature to 700°C) that are sensitive to impurities, for heat protection and pressure resistance of precision equipment and components; the high-temperature environment includes the area around precision sensors in aerospace engine compartments and the protection area of ​​temperature measuring elements in industrial high-temperature kilns.

[0042] In the aerospace field, this material is used for applications such as heat protection of precision pressure sensors in rocket engine compartments and components in satellite attitude control systems. It can withstand radiation temperatures up to 700°C and produces no volatile substances that contaminate the component surface, ensuring long-term operational accuracy.

[0043] In the industrial kiln sector: for example, protective sleeves for thermocouple temperature sensing elements inside high-temperature kilns. These sleeves can be used long-term in kiln environments up to 700℃, without residue clogging the temperature sensing channels, ensuring the accuracy and stability of temperature monitoring.

[0044] This alkali-free glass fiber paper is particularly suitable for high-temperature working environments sensitive to volatiles (including gases and liquids). It can maintain structural and performance stability under heat exposure of up to 700°C. It is suitable for applications such as the periphery of precision sensors in aerospace engine compartments, high-temperature packaging process cavities for semiconductor chips, and protective areas for temperature measuring elements in industrial high-temperature kilns, providing effective heat and pressure protection for precision equipment and core components.

[0045] In the above technical solution, this invention utilizes a combined process of "mechanical dissociation - ultrasonic and mechanical stirring circulation dispersion - papermaking - vacuum suction - heating and stamping" to produce 0.6-micron alkali-free glass fiber cotton as a single raw material. Vacuum suction removes air and moisture from the inside of the paper blank, and heating and stamping further compress the gaps between fibers. This allows the glass fibers to achieve dense shaping solely through physical winding and van der Waals forces, ultimately producing alkali-free glass fiber paper that is free of organic additives and inorganic impurities, has a dense structure, and can be stably used at 700℃. This meets the precision protection requirements of aerospace, industrial kilns, and other fields sensitive to high-temperature impurities. This invention aims to overcome the problems of existing glass fiber paper, such as the release of volatile gases and the deposition of impurities at high temperatures due to the addition of organic adhesives (e.g., phenolic resin, epoxy resin) or inorganic binders (e.g., silica sol, alumina sol), as well as the technical bottlenecks of insufficient mechanical properties (tensile strength typically <0.1MPa) and limited heat resistance caused by the loose structure.

[0046] The specific embodiments of the present invention will be described in further detail below with reference to examples, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention still fall within the scope of protection of the present invention.

[0047] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0048] The present invention will be described in detail below through specific embodiments, and the performance testing methods in each embodiment are as follows: Monofilament dispersion rate: Observed using an optical microscope (magnification 400×), 10 fields of view were randomly selected, and the proportion of glass fibers dispersed as monofilaments to the total number of glass fibers was counted and the average value was taken.

[0049] Thickness: Measured using a laser thickness gauge (accuracy ±0.001mm), with 5 measuring points taken at the center and four corners of the paper, and the average value was calculated.

[0050] Tensile strength: According to GB / T 12914-2018 "Determination of tensile strength of paper and paperboard", an electronic universal testing machine was used, with a sample width of 15 mm, a gauge length of 100 mm, and a tensile speed of 5 mm / min.

[0051] Heat resistance: The sample was placed in a constant temperature oven at 700℃ for 24 hours, then removed and cooled to room temperature in a desiccator. Its tensile strength was tested and the retention rate was calculated (strength after heating / initial strength × 100%).

[0052] Non-combustibility: According to GB / T 5464-2010 "Test Method for Non-combustibility of Building Materials", the test is carried out in a building materials non-combustibility test furnace, and the remaining length of combustion, presence of open flame and molten dripping phenomena are recorded.

[0053] Volatility: In accordance with GB / T 6040-2002 "General Rules for Infrared Spectroscopic Analysis", a Fourier transform infrared spectrometer was used to heat the sample in a heating device at 700℃, and the released gas components were detected through a gas cell to analyze the characteristic absorption peaks. Example 1

[0054] This embodiment provides a method for preparing alkali-free glass fiber paper, including the following steps: 1) Raw material pretreatment and mechanical dissociation: Take 50g of 0.6-micron alkali-free glass fiber cotton and add it to 13000g of deionized water (the mass ratio of deionized water to alkali-free glass fiber cotton is approximately 260:1). Stir in a high-speed shear mixer at 8000rpm for 3 minutes to fully dissociate the fiber bundles. After dissociation, take samples for testing. The monofilament dispersion rate reaches 92%. 2) Slurry preparation and dispersion stabilization: Five cycles of dispersion treatment were performed. Each cycle first involved ultrasonic dispersion (frequency 40kHz, time 10min), followed by high-speed mechanical stirring (speed 9000rpm, time 2min) to form a highly uniform and stable fiber slurry. 3) Papermaking and preliminary shaping: The above fiber pulp is pumped into a cylinder paper machine and papermaking is carried out under the process conditions of 15℃ and -0.4MPa to obtain a preliminary paper blank with a thickness of about 0.5mm; 4) Densification treatment: The obtained preliminary paper blank is subjected to vacuum suction and heating and pressing treatment at the same time. The vacuum degree is -0.08MPa, the heating temperature is 120℃, the pressing pressure is 1.2MPa, and the duration is 60min to obtain alkali-free glass fiber paper with a dense structure.

[0055] According to the test, the thickness of the alkali-free fiberglass paper in this embodiment is 0.18 mm and the tensile strength is 0.25 MPa.

[0056] After being treated at 700℃ for 24 hours, the tensile strength was 0.21 MPa, and the strength retention rate was 85%.

[0057] According to GB / T 5464-2010 non-flammability test, the remaining length after burning reaches 96%, and there is no open flame or melting dripping.

[0058] The gas released from the sample at 700℃ was detected by Fourier transform infrared spectroscopy. No obvious characteristic absorption peaks of organic or inorganic volatile components were detected, indicating that it is suitable for high-temperature environments sensitive to impurities. Example 2

[0059] This embodiment provides a method for preparing alkali-free glass fiber paper, including the following steps: 1) Raw material pretreatment and mechanical dissociation: Take 40g of 0.6-micron alkali-free glass fiber cotton and add it to 10800g of deionized water (the mass ratio of deionized water to alkali-free glass fiber cotton is approximately 270:1). Dissociate the fibers in a high-speed shear mixer at 9000rpm for 4 minutes to ensure complete fiber dissociation. After dissociation, take samples for testing, and the monofilament dispersion rate is measured to be 93%. 2) Slurry preparation and dispersion stabilization: Four repeated dispersion operations were performed. Each cycle first involved ultrasonic dispersion (frequency 45kHz, time 12min), followed by high-speed mechanical stirring (speed 10000rpm, time 3min) to form a highly uniform and stable fiber slurry. 3) Papermaking and preliminary shaping: The above fiber pulp is pumped into a cylinder paper machine and papermaking is carried out at 18℃ and -0.35MPa to obtain a preliminary paper blank with a thickness of about 0.6mm; 4) Densification treatment: The obtained preliminary paper blank is subjected to vacuum suction and heating and pressing treatment at the same time. The vacuum degree is -0.09Mpa, the heating temperature is 130℃, the pressing pressure is 1.5MPa, and the duration is 70min to obtain alkali-free glass fiber paper with a dense structure.

[0060] According to the test, the thickness of the alkali-free fiberglass paper in this embodiment is 0.20 mm and the tensile strength is 0.27 MPa.

[0061] After being kept at 700℃ for 24 hours, the tensile strength was 0.23 MPa, and the strength retention rate was 85%.

[0062] According to GB / T 5464-2010 non-flammability test, the remaining burning length reaches 97%, with no open flame / molten dripping.

[0063] The gas released from the sample at 700℃ was detected using a Fourier transform infrared spectrometer. No volatile component peaks were detected in the infrared spectrum at 700℃, which meets the requirements. Example 3

[0064] This embodiment provides a method for preparing alkali-free glass fiber paper, including the following steps: 1) Raw material pretreatment and mechanical dissociation: Take 60g of 0.6-micron alkali-free glass fiber cotton, add 15000g of deionized water (the mass ratio of deionized water to alkali-free glass fiber cotton is approximately 250:1), and dissociate it in a high-speed shear mixer at 10000rpm for 5min to fully dissociate the fiber bundles; after dissociation, take samples for testing, and the monofilament dispersion rate is measured to be 95%; 2) Slurry preparation and dispersion stabilization: Six repeated dispersion operations were performed. Each cycle first involved ultrasonic dispersion (frequency 50kHz, time 15min), followed by high-speed mechanical stirring (speed 12000rpm, time 4min) to form a highly uniform and stable fiber slurry. 3) Papermaking and preliminary shaping: The above fiber pulp is pumped into a cylinder paper machine and papermaking is carried out at 20℃ and -0.3Mpa to obtain a preliminary paper blank with a thickness of about 0.8mm; 4) Densification treatment: The obtained preliminary paper blank is subjected to vacuum suction and heating and pressing treatment at the same time. The vacuum degree is -0.10Mpa, the heating temperature is 150℃, the pressing pressure is 1.8MPa, and the duration is 80min to obtain alkali-free glass fiber paper with a dense structure.

[0065] According to the test, the thickness of the alkali-free fiberglass paper in this embodiment is 0.22 mm and the tensile strength is 0.26 MPa.

[0066] After being kept at 700℃ for 24 hours, the tensile strength was 0.22 MPa, and the strength retention rate was 86%.

[0067] According to GB / T 5464-2010 non-flammability test, the remaining length reached 99%, with no open flame / molten dripping.

[0068] The gas released from the sample at 700℃ was detected using a Fourier transform infrared spectrometer. No volatile component peaks were detected in the infrared spectrum at 700℃, which meets the requirements.

[0069] Comparative Example 1 Except for omitting the vacuum suction process in step 4) of Example 1, this comparative example only performs heating and stamping with the same parameters. All other steps and parameters are consistent with those of Example 1.

[0070] The test results of this comparative example show that when the thickness of the finished product increased to 0.25 mm, the tensile strength was only 0.2 MPa, significantly lower than the 2.0 MPa of Example 1. After being treated at 700℃ for 24 hours, the tensile strength decreased to 0.14 MPa, with a strength retention rate of only 70%. Observation revealed that the finished paper blank of this comparative example contained obvious residual air bubbles. These bubbles burst during the heating process, resulting in a loose and poorly compact structure in the final product. Vacuum suction is crucial for effectively removing air between fiber networks, preventing air bubble residue, and achieving a uniform and dense structure in the final product. Its absence directly leads to a significant decrease in the product's mechanical properties and heat resistance stability.

[0071] Comparative Example 2 Except for changing the number of cyclic dispersions in step 2) of Example 1 to 3 times, the other steps and parameters of this comparative example are exactly the same as those of Example 1.

[0072] In this comparative example, insufficient dispersion cycles resulted in inadequate fiber dispersion, leading to agglomeration in the pulp. This resulted in uneven paper thickness and a significant reduction in tensile strength to 0.13 MPa after papermaking. While no volatile component peaks were detected in the infrared spectrum at 700℃, the mechanical properties still failed to meet application requirements. Sufficient dispersion cycles are crucial for obtaining uniform pulp and high-performance finished products; too few cycles lead to insufficient dispersion and negatively impact product quality.

[0073] Comparative Example 3 Except for increasing the heating and stamping temperature in step 4) of Example 1 to 160°C, the other steps and parameters in this comparative example are the same as in Example 1.

[0074] In this comparative example, the excessively high processing temperature caused high-temperature aging and embrittlement of the glass fiber itself, resulting in damage to its microstructure. The tensile strength of the finished product significantly decreased to 0.15 MPa. After treatment at 700℃ for 24 hours, the strength retention rate further decreased to 65%, and the paper exhibited obvious brittleness and was prone to breakage. There is an optimal window for heating and stamping temperature (such as 120-150℃ within the scope of this invention). Temperatures below 120℃ are too low, resulting in insufficient fiber softening and loose entanglement; temperatures above 150℃ are too high, leading to fiber deterioration. The process parameter range of this invention ensures that the fibers are properly softened while avoiding thermal damage.

[0075] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0076] The numerical range described in this invention includes all values ​​within this range, and also includes any range value composed of any two values ​​within this range. Different values ​​of the same indicator appearing in all embodiments of this invention can be arbitrarily combined to form a range value.

[0077] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing alkali-free glass fiber paper, characterized in that, Includes the following steps: 1) Add alkali-free fiberglass wool to deionized water and disperse it fully through mechanical dissociation to obtain a dispersed alkali-free fiberglass wool slurry; 2) The alkali-free fiberglass slurry obtained in step 1) is subjected to repeated dispersion and mechanical stirring circulation treatment; 3) The slurry obtained in step 2) is subjected to a molding process to obtain the finished paper; 4) The formed paper obtained in step 3) is simultaneously subjected to vacuum suction treatment and heating and pressing treatment to compress the internal structure of the paper and make it dense, thereby obtaining the alkali-free glass fiber paper.

2. The method for preparing alkali-free glass fiber paper as described in claim 1, characterized in that, In step 1), the diameter of the alkali-free fiberglass cotton is 0.6 micrometers.

3. The method for preparing alkali-free glass fiber paper as described in claim 1, characterized in that, In step 1), the mechanical dissociation is carried out by high-speed shearing and stirring, with a stirring speed of 8000~10000 rpm and a dissociation time of 3~5 min; the monofilament dispersion rate of the alkali-free fiberglass cotton after dissociation is ≥90%; the mass ratio of the deionized water to the dispersed alkali-free fiberglass cotton is (250~270):

1.

4. The method for preparing alkali-free glass fiber paper as described in claim 1, characterized in that, In step 2), the number of repeated dispersion treatments is 4 to 6 times; each dispersion treatment first uses ultrasonic-assisted ultrasonic power of 40 to 50 kHz and dispersion time of 10 to 15 min, and then stirs at a speed of 9000 to 12000 rpm for 2 to 4 min.

5. The method for preparing alkali-free glass fiber paper as described in claim 1, characterized in that, In step 3), the papermaking temperature of the papermaking process is 15~20℃, the papermaking vacuum degree is -0.4~-0.3MPa, and the thickness of the initial paper blank is 0.5~0.8mm.

6. The method for preparing alkali-free glass fiber paper as described in claim 1, characterized in that, In step 4), the vacuum degree of the vacuum suction process is -0.08 to -0.10 MPa; the temperature of the heating and stamping process is 120 to 150°C, the stamping pressure is 1.2 to 1.8 MPa, and the suction and stamping time is 60 to 80 minutes.

7. An alkali-free glass fiber paper, characterized in that, The alkali-free fiberglass paper is prepared by the method described in any one of claims 1-6.

8. The alkali-free glass fiber paper as described in claim 7, characterized in that, The alkali-free fiberglass paper has a thickness of 0.18~0.22mm, a heat resistance temperature of 700℃, and conforms to the GB / T 5464-2010 standard for non-combustible materials; no gas or liquid substances are released when heated to 700℃.

9. The application of an alkali-free glass fiber paper in a high-temperature environment sensitive to impurities, characterized in that... The temperature range of the high-temperature environment is from room temperature to 700℃.

10. The application of the alkali-free glass fiber paper as described in claim 9 in a high-temperature environment sensitive to impurities, characterized in that... The high-temperature environment includes the area surrounding precision sensors inside aerospace engine compartments and the protected area for temperature measuring elements inside industrial high-temperature kilns.