A reusable ultra-high purity paper and a method for making the same

Abstract

The application relates to the papermaking technical field, and discloses a reusable ultrahigh-purity paper and a preparation method thereof.A preparation method of a reusable ultrahigh-purity paper comprises the following steps: taking high-purity cellulose pulp plates, dispersing the high-purity cellulose pulp plates in deionized water, and then performing a deconstruction treatment to prepare paper pulp; performing ultrasonic treatment on the paper pulp in an acid medium, and then performing ultrasonic treatment on the paper pulp in ethanol to prepare purified paper pulp; washing the purified paper pulp with deionized water; obtaining original paper through self-assembly forming and drying treatment of the washed paper pulp; coating resin on the surface of the original paper; performing hot-pressing treatment and corona treatment on the original paper coated with the resin, and then performing high-temperature treatment and packaging to obtain the reusable ultrahigh-purity paper.The preparation method is simple in operation, high in production efficiency, and meets the environmental protection requirements; the prepared ultrahigh-purity paper is high in purity, low in impurity content, and can meet the demand of sampling paper.

Description

Technical Field

[0001] This application relates to the field of papermaking technology, and in particular to a reusable ultra-high purity paper and a method for preparing the same. Background Technology

[0002] With the development of technology and people’s increasing demands for the accuracy and reliability of testing, the performance requirements for sampling paper are also getting higher and higher.

[0003] Current sampling papers have several problems. First, many sampling papers are of insufficient quality and performance, with high impurity content and low purity, affecting the accuracy and reliability of testing. Second, the types and applications of sampling papers are limited; different fields require different sampling papers, but the market offers relatively few choices. Furthermore, the vast majority of sampling papers are for single use only, resulting in significant waste, and their high price increases testing costs for fields requiring large quantities.

[0004] Therefore, the development of high-quality, high-performance sampling paper has become an urgent market demand. Summary of the Invention

[0005] In order to solve at least one of the above-mentioned technical problems and develop a high-quality, high-performance sampling paper, this application provides a reusable ultra-high purity paper and a method for preparing the same.

[0006] On the one hand, this application provides a method for preparing reusable ultra-high purity paper, comprising the following steps:

[0007] S1. After dispersing high-purity cellulose pulp in deionized water, deconstruction treatment is carried out to prepare pulp with a freeness of 50-90°SR.

[0008] S2. The pulp is first ultrasonically treated in an acidic medium, and then ultrasonically treated in ethanol to prepare purified pulp.

[0009] S3. The purified pulp is washed with deionized water until the pH is 6.5-7.5.

[0010] S4. The washed pulp is self-assembled and dried to obtain the base paper.

[0011] S5. Apply the resin to the surface of the base paper, with a coating amount of 10-40 g / m². 2 ;

[0012] S6. The resin-coated base paper is subjected to hot pressing to obtain base paper I;

[0013] S7. The base paper I is subjected to corona treatment to obtain base paper II;

[0014] S8. The base paper II is subjected to high temperature treatment and then packaged to obtain a reusable ultra-high purity paper.

[0015] By adopting the above technical solution, the specific reusable ultra-high purity paper preparation method of this application is simple to operate, has high production efficiency, and can meet the needs of large-scale production. At the same time, it uses environmentally friendly and biodegradable raw materials, which meets environmental protection requirements. The ultra-high purity paper prepared by this application has the advantages of high purity, low impurity content, excellent mechanical properties and environmental degradability, which can meet the needs of sampling paper. After use, it can be reused by repeating step S8 without affecting the detection rate.

[0016] In S1 of this application, controlling a specific pulp beating degree deconstructs the fibers in the pulp, which not only opens channels for the dissolution of impurities during subsequent ultrasonic treatment, improving purification efficiency and effect, but also enhances the strength and density of the base paper. In S2 of this application, the pulp is first ultrasonically treated in an acidic medium to quickly remove metal ions and reduce impurity content, and then ultrasonically treated in ethanol to quickly remove extractives from the pulp, further purifying it. In S3 of this application, multiple washings with deionized water effectively remove acid and ethanol impurities from the pulp. Application S5 uses a specific resin for coating, which effectively improves the hydrophobicity, cleaning ability, and temperature resistance of the base paper; in application S6, a specific heating and pressurizing method is used to further increase the strength and density of the base paper; in application S7, a specific corona treatment is used to further clean the surface, while also improving surface adhesion and wettability; in application S8, the corona-treated material is subjected to high-temperature treatment in a clean forced-air drying oven to further improve the surface purity of the material; and the used paper sample can be reused after processing in S8.

[0017] Optionally, in S1, the high-purity cellulose pulp board is selected from one or more of mercerizing pulp, insulating pulp, cotton pulp, dissolving pulp, and regenerated cellulose pulp.

[0018] Optionally, in step S2, the acidic medium is selected from hydrochloric acid or sulfuric acid; the concentration of the acidic medium is 1-3 wt%.

[0019] By adopting the above technical solution, this application uses a specific acid and controls the acid concentration, which is beneficial to improving the cleanliness and purity of the pulp, and also helps with subsequent ultrasonic treatment and avoids excessive corrosion of the pulp.

[0020] Optionally, in S2, the frequency of ultrasonic treatment is 10-60kHz, the power is 100-300kW, and the time is 40-80min.

[0021] By adopting the above technical solution, the specific ultrasonic treatment process used in S2 of this application is beneficial to pulp purification.

[0022] Optionally, in step S4, the thickness of the base paper is 110-200 μm, and the basis weight is 80-120 g / m². 2 .

[0023] Optionally, in S5, the resin is selected from one or more of aramid resin, aramid sulfone resin, polyimide resin, and polytetrafluoroethylene resin.

[0024] Optionally, in S6, the hot-pressing temperature is 90-300℃, and the thickness of the base paper is controlled to be 110-200μm.

[0025] Optionally, in S7, the voltage of the corona treatment is 3-25kV.

[0026] Preferably, in step S7, the voltage of the corona treatment is 5-20 kV.

[0027] Preferably, in step S7, the voltage of the corona treatment is 10-15 kV.

[0028] Optionally, in S8, the high-temperature treatment temperature is 200-300℃ and the time is 10-30 minutes.

[0029] On the other hand, this application provides a reusable ultra-high purity paper, which is prepared by a method for preparing reusable ultra-high purity paper.

[0030] In summary, the present invention has at least one of the following beneficial technical effects:

[0031] 1. The specific method for preparing reusable ultra-high purity paper used in this application is simple to operate, has high production efficiency, and can meet the needs of large-scale production. At the same time, it uses environmentally friendly and biodegradable raw materials, which meet environmental protection requirements.

[0032] 2. The pulp of this application is deconstructed and then ultrasonically purified in acid and ethanol. The deconstruction treatment improves the purification efficiency and effect, and the pulp and base paper have extremely high purity.

[0033] 3. This application uses corona treatment to process smooth and clean paper surfaces, which increases surface roughness, surface adhesion and wettability, and improves collection efficiency;

[0034] 4. The ultra-high purity paper prepared in this application has the advantages of high purity, low impurity content, excellent mechanical properties and environmental degradability, which can meet the requirements of sampling paper; and after use, it can be reused by repeating step S8 without affecting the detection rate. Detailed Implementation

[0035] The present application will be further described in detail below with reference to the embodiments.

[0036] This application presents a method for preparing reusable ultra-high purity paper, comprising the following steps:

[0037] S1. After dispersing high-purity cellulose pulp in deionized water, deconstruction treatment is carried out to prepare pulp with a freeness of 50-90°SR.

[0038] S2. The pulp is first ultrasonically treated in an acidic medium, and then ultrasonically treated in ethanol to prepare purified pulp.

[0039] S3. The purified pulp is washed with deionized water until the pH is 6.5-7.5.

[0040] S4. The washed pulp is self-assembled and dried to obtain the base paper.

[0041] S5. Apply the resin to the surface of the base paper, with a coating amount of 10-40 g / m². 2 ;

[0042] S6. The resin-coated base paper is subjected to hot pressing to obtain base paper I;

[0043] S7. The base paper I is subjected to corona treatment to obtain base paper II;

[0044] S8. The base paper II is subjected to high temperature treatment and then packaged to obtain a reusable ultra-high purity paper. Specific Implementation

[0046] The raw materials used in this application are as follows. Unless otherwise specified, all raw materials used in this application are commercially available:

[0047] Mercerizing paste: Domtar, a Canadian company; brand name: Rainbow Fish.

[0048] Insulating grout: Northern Wood Pulp Mills, Canada; brand: Prince George.

[0049] Cotton pulp: Anhui Xuelong Fiber Technology Co., Ltd.;

[0050] Dissolving slurry: Hunan Juntian New Material Technology Co., Ltd., brand: Junsong;

[0051] Regenerated cellulose pulp: Baoding Swan New Fiber Manufacturing Co., Ltd.;

[0052] Aramid resin: Taihe New Materials Group Co., Ltd., brand: Taimeida;

[0053] Aramid sulfone resin: Zhongfang Special Fiber Co., Ltd.;

[0054] Polyimide resin: 99% purity, Hubei Xinkang Pharmaceutical Chemical Co., Ltd.;

[0055] Polytetrafluoroethylene resin: 99% purity, brand: Yuanye;

[0056] Nitrobenzene: 99% purity.

[0057] Testing items and methods:

[0058] Conductivity of water extract: Tested according to the standard GB / T 7977-2007 Determination of conductivity of water extract of paper, paperboard and pulp;

[0059] Ethanol extract content: Tested according to the standard GB / T 2677.6-1994 - Determination of extract content of organic solvents in papermaking raw materials;

[0060] Smoothness: Tested according to the standard GB / T 22881-2008 Determination of Roughness (Smoothness) of Paper and Paperboard;

[0061] Ash content: Tested according to the standard GB / T 742-2008 Determination of ash content in papermaking raw materials, pulp, paper and paperboard;

[0062] Water absorption (Cobb method): Tested according to the standard GB / T 1540-2002 Determination of water absorption of paper and paperboard (Cobb method); Bursting strength: Tested according to the standard GB / T 454-2020 Determination of bursting strength of paper;

[0063] Stiffness: Performance testing was conducted according to the standard GB / T 22364-2008 Determination of Bending Stiffness of Paper and Paperboard.

[0064] Examples 1-5

[0065] Example 1

[0066] A method for preparing reusable ultra-high purity paper includes the following steps:

[0067] S1. After dispersing the insulating pulp board in deionized water, it is deconstructed in a disc mill to prepare pulp with a freeness of 85°SR.

[0068] S2. The pulp is first ultrasonically treated in 1.5wt% hydrochloric acid, and then ultrasonically treated in 95wt% ethanol to prepare purified pulp. The ultrasonic treatment in hydrochloric acid and ethanol is performed at a frequency of 20kHz, a power of 100kw, and a time of 60min.

[0069] S3. Wash the purified pulp with deionized water until the pH reaches 7.0;

[0070] S4. The washed pulp is self-assembled and dried to obtain base paper with a thickness of 130μm and a basis weight of 110g / m². 2 ;

[0071] S5. Apply aramid resin to the surface of the base paper, with a coating amount of 20 g / m². 2 ;

[0072] S6. The resin-coated base paper is subjected to hot pressing treatment at a temperature of 150℃ and the thickness of the base paper is controlled to be 145μm to obtain base paper I.

[0073] S7. Perform corona treatment on the base paper I at a voltage of 10kV to obtain base paper II;

[0074] S8. The base paper II is subjected to high-temperature treatment at 200℃ for 10 minutes, and then packaged to obtain ultra-high purity paper that can be reused.

[0075] Example 2

[0076] A method for preparing reusable ultra-high purity paper includes the following steps:

[0077] S1. After dispersing the cotton pulp board in deionized water, it is deconstructed in a disc mill to prepare pulp with a freeness of 50°SR.

[0078] S2. The pulp is first ultrasonically treated in 1.5wt% sulfuric acid, and then ultrasonically treated in 95wt% ethanol to prepare purified pulp. The ultrasonic treatment frequency is 10kHz, the power is 200kw, and the time is 50min.

[0079] S3. Wash the purified pulp with deionized water until the pH reaches 6.5;

[0080] S4. The washed pulp is self-assembled and dried to obtain base paper with a thickness of 110μm and a basis weight of 80g / m². 2 ;

[0081] S5. Apply aramid resin to the surface of the base paper, with a coating amount of 30 g / m². 2 ;

[0082] S6. The resin-coated base paper is subjected to hot pressing treatment at a temperature of 90°C and the thickness of the base paper is controlled to be 130μm to obtain base paper I.

[0083] S7. Perform corona treatment on the base paper I at a voltage of 10kV to obtain base paper II;

[0084] S8. The base paper II is subjected to high-temperature treatment at 240℃ for 30 minutes, and then packaged to obtain ultra-high purity paper that can be reused.

[0085] Example 3

[0086] A method for preparing reusable ultra-high purity paper includes the following steps:

[0087] S1. After dispersing the mercerized pulp board in deionized water, it is deconstructed in a disc mill to prepare pulp with a freeness of 75°SR.

[0088] S2. The pulp is first ultrasonically treated in 1.0wt% hydrochloric acid, and then ultrasonically treated in 95wt% ethanol to prepare purified pulp. The ultrasonic treatment frequency is 50kHz, the power is 300kw, and the time is 80min.

[0089] S3. Wash the purified pulp with deionized water until the pH reaches 6.8;

[0090] S4. The washed pulp is paper-formed and dried to prepare base paper with a thickness of 135μm and a basis weight of 120g / m². 2 ;

[0091] S5. Apply polyimide resin to the surface of the base paper, with a coating amount of 10 g / m². 2 ;

[0092] S6. The resin-coated base paper is subjected to hot pressing treatment at a temperature of 200℃ and the thickness of the base paper is controlled to be 130μm to obtain base paper I.

[0093] S7. Perform corona treatment on the base paper I at a voltage of 10kV to obtain base paper II;

[0094] S8. The base paper II is subjected to high-temperature treatment at 300℃ for 10 minutes, and then packaged to obtain ultra-high purity paper that can be reused.

[0095] Example 4

[0096] A method for preparing reusable ultra-high purity paper includes the following steps:

[0097] S1. Disperse the dissolved pulp board in deionized water and then decompose it in a disc mill to prepare pulp with a freeness of 65°SR.

[0098] S2. The pulp is first ultrasonically treated in 3.0wt% hydrochloric acid, and then ultrasonically treated in 95wt% ethanol to prepare purified pulp. The ultrasonic treatment frequency is 60kHz, the power is 100kw, and the time is 70min.

[0099] S3. Wash the purified pulp with deionized water until the pH reaches 7.2;

[0100] S4. The washed pulp is paper-formed and dried to prepare base paper with a thickness of 200μm and a basis weight of 115g / m². 2 ;

[0101] S5. Apply polytetrafluoroethylene resin to the surface of the base paper, with a coating amount of 40 g / m². 2 ;

[0102] S6. The resin-coated base paper is subjected to hot pressing treatment at a temperature of 300℃ and the thickness of the base paper is controlled to be 200μm to obtain base paper I.

[0103] S7. Perform corona treatment on the base paper I at a voltage of 10kV to obtain base paper II;

[0104] S8. The base paper II is subjected to high-temperature treatment at 280℃ for 15 minutes, and then packaged to obtain ultra-high purity paper that can be reused.

[0105] Example 5

[0106] A method for preparing reusable ultra-high purity paper includes the following steps:

[0107] S1. After dispersing the regenerated cellulose pulp board in deionized water, it is deconstructed in a disc mill to prepare pulp with a freeness of 90°SR.

[0108] S2. The pulp is first ultrasonically treated in 1.0wt% sulfuric acid, and then ultrasonically treated in 95wt% ethanol to prepare purified pulp. The ultrasonic treatment frequency is 40kHz, the power is 200kw, and the time is 40min.

[0109] S3. Wash the purified pulp with deionized water until the pH reaches 7.5.

[0110] S4. The washed pulp is paper-formed and dried to prepare base paper with a thickness of 120μm and a basis weight of 100g / m². 2 ;

[0111] S5. Apply aramid resin to the surface of the base paper at a coating weight of 15 g / m². 2 ;

[0112] S6. The resin-coated base paper is subjected to hot pressing treatment at a temperature of 250℃ and the thickness of the base paper is controlled to be 110μm to obtain base paper I.

[0113] S7. Perform corona treatment on the base paper I at a voltage of 10kV to obtain base paper II;

[0114] S8. The base paper II is subjected to high-temperature treatment at 210℃ for 30 minutes, and then packaged to obtain ultra-high purity paper that can be reused.

[0115] Comparative Example 1

[0116] Based on Example 3, except for step S2, the preparation methods are the same as in Example 3; S2: The pulp in S1 is directly subjected to ultrasonic treatment in ethanol to prepare purified pulp. The ultrasonic treatment frequency is 50kHz, the power is 300kw, and the time is 80min.

[0117] Comparative Example 2

[0118] Based on Example 3, except that step S5 is omitted, i.e., no resin is used for coating, the preparation method is the same as in Example 3.

[0119] Comparative Example 3

[0120] Based on Example 3, except that step S8 is not included, i.e., corona treatment is not used, the preparation method is the same as in Example 3.

[0121] Comparative Example 4

[0122] Based on Example 3, except that the pulp freeness in S1 is 40°SR, the rest of the preparation methods are the same as in Example 3.

[0123] Comparative Example 5

[0124] Based on Example 3, except that the coating amount in S5 is 8 g / m 2 Except for the preparation method, all other preparation methods are the same as in Example 3.

[0125] Comparative Example 6

[0126] Based on Example 3, except that the coating amount in S5 is 45 g / m 2 Except for the preparation method, all other preparation methods are the same as in Example 3.

[0127] The pure papers prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to performance testing, and the test results are shown in Table 1.

[0128] Table 1

[0129]

[0130]

[0131] As can be seen from Examples 1-5, Comparative Examples 1-6 and Table 1, the present application adopts a specific method for preparing reusable ultra-high purity paper, which is simple to operate, has high production efficiency, and can meet the needs of large-scale production. At the same time, the ultra-high purity paper prepared has the advantages of high purity, low impurity content, excellent mechanical properties and environmental degradability.

[0132] As can be seen from Comparative Example 1, Example 3 and Table 1, in S2 of this application, ultrasonic treatment of pulp in an acidic medium can effectively reduce impurity content, reduce the conductivity of water extract and reduce ash content.

[0133] As can be seen from Comparative Example 2, Example 3 and Table 1, the specific resin coating process used in this application can effectively improve the smoothness and burst strength of the prepared pure paper.

[0134] As can be seen from Comparative Example 3, Example 3 and Table 1, the present application uses a specific corona process, which reduces the smoothness but effectively improves the Cobb value and burst strength.

[0135] As can be seen from Comparative Example 4, Example 3 and Table 1, the specific beating degree used in this application is beneficial to improving the smoothness and burst strength of the prepared pure paper;

[0136] As can be seen from Comparative Examples 5-6, Example 3 and Table 1, the pure paper prepared by this application using a specific amount of resin coating has better overall performance.

[0137] Examples 6-10

[0138] Based on Example 3, except for the different voltage of the corona treatment in S7, the preparation methods are the same as in Example 3.

[0139] Example 6

[0140] In S7, the voltage for corona treatment is 3kV.

[0141] Example 7

[0142] In S7, the voltage for corona treatment is 5kV.

[0143] Example 8

[0144] In S7, the voltage for corona treatment is 15kV.

[0145] Example 9

[0146] In S7, the voltage for corona treatment is 20kV.

[0147] Example 10

[0148] In S7, the voltage for corona treatment is 25kV.

[0149] The pure paper prepared in Examples 6-10 was subjected to performance testing, and the test results are shown in Table 2.

[0150] Table 2

[0151]

[0152]

[0153] As can be seen from Examples 6-10, 3 and Table 2, the voltage of the corona treatment in this application is controlled at 5-20kV. Furthermore, when the voltage is controlled at 10-15kV, the overall performance of the prepared pure paper is even better.

[0154] Application Examples 1-3

[0155] Application Example 1

[0156] The pure paper prepared in Example 3 was used as the sampling paper.

[0157] The method of use is as follows: Take 100 1μL nitrobenzene solutions (prepare nitrobenzene and deionized water to a concentration of 1ng / mL) and drop them onto 100 sampling papers respectively. After standing for 30 seconds, place the sampling paper into ion mobility spectrometry (IMS) for detection and record whether it is detected; record the detection rate and false alarm rate.

[0158] Application Example 2

[0159] Take 100 samples of the sampling paper used once in Application Example 1, and treat them at 300℃ for 10 minutes. Then repeat the operation in Application Example 1, that is, take 100 1μL nitrobenzene solution (nitrobenzene concentration of 1ng / mL) and drop them onto 100 samples of the sampling paper. After standing for 30 seconds, put the sampling paper into ion mobility spectrometry (IMS) for detection, record whether it is detected, and record the detection rate and false alarm rate.

[0160] Application Example 3

[0161] Take 100 samples of the sampling paper that were reused twice in Application Example 2, and treat them at a high temperature of 300℃ for 10 minutes. Then repeat the operation in Application Example 2 18 times, that is, the sampling paper was used a total of 20 times. Record whether it was detected, and record the detection rate and false alarm rate.

[0162] Application Example 4-8

[0163] Based on Application Example 1, except for the source of the sampling paper, the usage method is the same as in Application Example 1.

[0164] Application Example 4

[0165] The pure paper prepared in Example 6 was used as the sampling paper.

[0166] Application Example 5

[0167] The pure paper prepared in Example 7 was used as the sampling paper.

[0168] Application Example 6

[0169] The pure paper prepared in Example 8 was used as the sampling paper.

[0170] Application Example 7

[0171] The pure paper prepared in Example 9 was used as the sampling paper.

[0172] Application Example 8

[0173] The pure paper prepared in Example 10 was used as the sampling paper.

[0174] Application Comparative Example 1

[0175] Based on Application Example 1, except that the pure paper prepared in Comparative Example 2 was used as the sampling paper, all other usage methods were the same as in Application Example 1.

[0176] Application Comparative Example 2

[0177] Based on Application Example 1, except that the pure paper prepared in Comparative Example 3 was used as the sampling paper, all other usage methods were the same as in Application Example 1.

[0178] The detection rates of Application Examples 1-8 and Application Comparative Examples 1-2 were calculated. The detection rate = number of positive detections / total number of samples * 100%. The results are shown in Table 3.

[0179] Table 3

[0180]

[0181] As can be seen from Application Examples 1-3, Comparative Examples 1-2 and Table 3, using the pure paper prepared in this application as sampling paper results in a high detection rate of nitrobenzene and a low false alarm rate; and the used sampling paper can be reused after high-temperature treatment without affecting the detection rate of the drug.

[0182] As can be seen from Application Examples 4-8 and Table 3, the control of the pressure range of the corona treatment in this application is beneficial to improving the detection rate of nitrobenzene and reducing the false alarm rate.

[0183] As can be seen from Comparative Example 1 and Table 3, the pure paper prepared without resin coating in this application, when used as sampling paper, has an extremely low detection rate of drugs, which seriously affects the detection rate.

[0184] As can be seen from Comparative Example 2 and Table 3, the detection rate of drugs is relatively low when using pure paper prepared without corona treatment as sampling paper.

[0185] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the principles of this application should be covered within the scope of protection of this application.

Claims

1. A method for preparing reusable ultra-high purity paper, characterized in that, Includes the following steps: S1. After dispersing high-purity cellulose pulp in deionized water, deconstruction treatment is carried out to prepare pulp with a freeness of 50-90°SR. S2. The pulp is first ultrasonically treated in an acidic medium, and then ultrasonically treated in ethanol to prepare purified pulp. S3. The purified pulp is washed with deionized water until the pH is 6.5-7.

5. S4. The washed pulp is self-assembled and dried to obtain the base paper. S5. Apply the resin to the surface of the base paper, with a coating amount of 10-40 g / m². 2 ; S6. The resin-coated base paper is subjected to hot pressing to obtain base paper I; S7. The base paper I is subjected to corona treatment to obtain base paper II; S8. The base paper II is subjected to high-temperature treatment and then packaged to obtain reusable ultra-high purity paper; In step S5, the resin is selected from one or more of aramid resin, aramid sulfone resin, polyimide resin, and polytetrafluoroethylene resin; In S8, the high-temperature treatment temperature is 200-300℃ and the time is 10-30 minutes.

2. The method for preparing reusable ultra-high purity paper according to claim 1, characterized in that, In S1, the high-purity cellulose pulp board is selected from one or more of mercerizing pulp, insulating pulp, cotton pulp, dissolving pulp, and regenerated cellulose pulp.

3. The method for preparing reusable ultra-high purity paper according to claim 1, characterized in that, In S2, the acidic medium is selected from hydrochloric acid or sulfuric acid; the concentration of the acidic medium is 1-3 wt%.

4. The method for preparing reusable ultra-high purity paper according to claim 1, characterized in that, In step S2, the ultrasonic treatment in the acidic medium has a frequency of 10-60 kHz, a power of 100-300 kW, and a time of 40-80 min. The ultrasonic treatment in ethanol also has a frequency of 10-60 kHz, a power of 100-300 kW, and a time of 40-80 min.

5. The method for preparing reusable ultra-high purity paper according to claim 1, characterized in that, In step S4, the thickness of the base paper is 110-200 μm, and the basis weight is 80-120 g / m². 2 .

6. The method for preparing reusable ultra-high purity paper according to claim 1, characterized in that, In step S6, the hot-pressing temperature is 90-300℃, and the thickness of the base paper is controlled to be 110-200μm.

7. The method for preparing reusable ultra-high purity paper according to claim 1, characterized in that, In S7, the voltage for corona treatment is 3-25kV.

8. A reusable ultra-high purity paper, characterized in that, It is prepared by the method for preparing reusable ultra-high purity paper according to any one of claims 1-7.

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