A fluorescent shielding adhesive, its preparation method and application

Abstract

This application discloses a fluorescent shielding adhesive, its preparation method, and its application, relating to the field of papermaking technology, aiming to solve the technical problem that existing synthetic fiber paper cannot meet application requirements. The fluorescent shielding adhesive comprises the following components: an adhesive, a mixture of diethylene glycol diethyl ether and benzotriazole. Unlike other particulate chemical coatings, the fluorescent shielding adhesive of this application is hydrophilic. Therefore, after surface sizing treatment of synthetic fiber paper, it does not affect the paper's air permeability, surface strength, or watermark anti-counterfeiting effect under light transmission. While meeting the requirement of no fluorescent reaction in special papers, it does not affect the papermaking performance and anti-counterfeiting properties, thus better meeting application needs.

Description

Technical Field

[0001] This application relates to the field of papermaking technology, and in particular to a fluorescent shielding adhesive liquid, its preparation method and application. Background Technology

[0002] Synthetic fiber paper is paper made from synthetic fiber raw materials (such as aramid, polyimide, or nylon) using wet or dry processes. Due to its superior properties compared to plant fiber paper in terms of mechanical strength, water resistance, color-changing anti-counterfeiting features, and paper texture, synthetic fiber paper is a typical representative of high-performance specialty paper products. However, typical synthetic fiber paper exhibits strong fluorescence, which makes it unsuitable for certain specialized applications.

[0003] Therefore, existing technologies often use granular chemical coatings such as titanium dioxide or calcium carbonate to shield the fluorescence reaction, but at the same time, this will affect other properties of synthetic fiber paper, thus limiting its application. Summary of the Invention

[0004] This application provides a fluorescent shielding adhesive liquid, its preparation method, and its application, aiming to solve the technical problem that existing synthetic fiber paper cannot meet application requirements.

[0005] To address the aforementioned technical problems, embodiments of this application provide: a fluorescent shielding adhesive, comprising the following components: an adhesive, a mixture of diethylene glycol diethyl ether and benzotriazole.

[0006] As some optional embodiments of this application, the mass ratio of the diethylene glycol diethyl ether to the adhesive solution is 5%-15%, and the mass ratio of the benzotriazole mixture to the adhesive solution is 5%-15%.

[0007] As some optional embodiments of this application, each part of the adhesive solution includes the following components by weight: 5-12 parts polyvinyl alcohol, 1-3 parts urea, 0.3-0.8 parts wet strength agent stock solution, 0.03-0.3 parts melamine and 87-95 parts water.

[0008] As some optional embodiments of this application, each part of the adhesive solution includes the following components by weight: 5-10 parts polyvinyl alcohol, 1-2 parts urea, 0.5-0.6 parts wet strength agent stock solution, 0.05-0.2 parts melamine and 88.5-93.45 parts water.

[0009] As some optional embodiments of this application, the wet strength agent stock solution is polyamide epichlorohydrin resin;

[0010] The mass fraction of the diethylene glycol diethyl ether is 95%-99%;

[0011] The benzotriazole mixture has a mass fraction of 10%-20%.

[0012] As some optional embodiments of this application, the viscosity of the fluorescent shielding adhesive is 15cp-35cp.

[0013] Furthermore, embodiments of this application provide a method for preparing the fluorescent shielding adhesive solution as described above, comprising the following steps:

[0014] Melamine, wet strength agent stock solution, polyvinyl alcohol and urea are added to water in proportion, heated to 90℃-95℃ and stirred to the preset concentration to obtain the adhesive solution.

[0015] At room temperature, the mixture of diethylene glycol diethyl ether and benzotriazole was mixed thoroughly to obtain a clear liquid;

[0016] After the adhesive solution is cooled to room temperature, it is mixed with the clarified liquid and mixed evenly to obtain a fluorescent shielding adhesive solution.

[0017] In another aspect, embodiments of this application provide an application of the fluorescent shielding adhesive liquid described above for shielding the fluorescence of synthetic fiber paper.

[0018] As some optional embodiments of this application, when the fluorescent shielding adhesive is used to shield the fluorescence of synthetic fiber paper, the surface sizing treatment is performed by impregnation roller or coating.

[0019] As some optional embodiments of this application, when the fluorescent shielding adhesive is used to shield the fluorescence of synthetic fiber paper, the proportion of each component in the fluorescent shielding adhesive is obtained based on the initial fluorescence brightness value of the synthetic fiber paper.

[0020] Compared with existing technologies, the fluorescent shielding adhesive provided in this application comprises the following components: an adhesive, a mixture of diethylene glycol diethyl ether and benzotriazole. It can be seen that the fluorescent shielding adhesive described in this application differs from other particulate chemical coatings. The fluorescent shielding adhesive described in this application is hydrophilic; therefore, after surface sizing treatment of synthetic fiber paper, it will not affect the paper's air permeability, surface strength, or watermark anti-counterfeiting effect under transmitted light. While meeting the requirement of no fluorescent reaction for special papers, it does not affect the paper's papermaking performance and anti-counterfeiting properties, thus better meeting application needs. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0022] Figure 1 This is a schematic diagram of the preparation method of the fluorescent shielding adhesive involved in this application.

[0023] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] Fluorescence is the process by which a substance is excited by ultraviolet light and then converts the excited energy into visible light. The principle behind fluorescence is that when light shines on certain atoms, the energy of the light causes some electrons around the atomic nucleus to jump from their original orbits to higher energy orbits, i.e., from the ground state to the first or second excited singlet state, etc. These first or second excited singlet states are unstable and will return to the ground state. When the transitioned electrons return to the ground state, the energy is released in the form of light, thus producing fluorescence.

[0026] Synthetic fiber paper is paper made from synthetic fiber raw materials (such as aramid, polyimide, nylon, etc.) using wet or dry processes. Due to its superior properties in terms of mechanical strength, water resistance, color-changing anti-counterfeiting, and paper texture compared to plant fiber paper, synthetic fiber paper is a typical representative of high-performance specialty paper products. However, many types of synthetic fibers are fluorescent substances. This is because the necessary condition for fluorescence is that the molecule must have a structure capable of absorbing excitation light. The chemical groups in the molecular chains of synthetic fibers mostly contain conjugated systems of carbonyl groups, carbon-nitrogen double bonds, and benzene rings, i.e., structures capable of absorbing excitation light. This results in synthetic fiber security paper exhibiting a strong fluorescent reaction, which contradicts the requirement of non-fluorescent reaction for high-grade security paper, thus limiting the application of synthetic fibers in the field of high-grade security paper.

[0027] In existing technologies, to address the problem of strong fluorescence in synthetic fiber paper, one of the following methods is typically employed: Chemical treatment, which uses specific chemicals, such as bleaching agents or oxidizing agents, to induce an oxidation-reduction reaction in the fibers to remove the fluorescence; however, this method may damage the fibers to some extent and affect their strength and durability. Another method is ultraviolet irradiation, which uses ultraviolet light to destroy the fluorescent substances in the fibers; however, this method usually requires specific equipment and techniques and is time-consuming. A third method is heat treatment, which involves subjecting the fibers to high temperatures to destroy the fluorescent substances; however, this method may require high-temperature equipment and techniques and is costly.

[0028] However, the above removal methods may cause excessive damage to the fibers in the paper, resulting in a decline in paper quality and reduced durability.

[0029] Therefore, some scholars have proposed the following measures to reduce fiber damage when implementing the above three methods: For example, when using chemical treatment, select appropriate chemical agents and control the treatment time and concentration to minimize fiber damage; protective agents or antioxidants can be used to protect the fibers from excessive damage during chemical treatment. When using ultraviolet irradiation, control the duration and intensity of ultraviolet irradiation to avoid excessive irradiation leading to fiber damage; simultaneously, other measures can be taken, such as using ultraviolet absorbers or antioxidants to protect the fibers. Similarly, when using heat treatment, control the heating time and temperature to avoid excessive heating leading to fiber damage; simultaneously, appropriate heat treatment methods, such as steam heat treatment or infrared heat treatment, can be selected to reduce fiber damage. Furthermore, other measures can be taken during the treatment process, such as slow cooling or the use of protective agents to reduce fiber damage.

[0030] However, while the above measures can reduce the degree of damage to the fibers, they also affect the removal effect of the fluorescence reaction.

[0031] Therefore, this application proposes a surface sizing process and develops a surface sizing liquid with fluorescence shielding function to coat the paper with a fluorescence shielding layer, so as to eliminate the fluorescence of the paper without affecting other properties of the paper.

[0032] Specifically, to address the aforementioned technical problems, this application provides a fluorescent shielding adhesive with a viscosity of 15cp-35cp. This adhesive exhibits excellent film-forming properties and penetration into paper, providing both fluorescent shielding and superior mechanical strength and water resistance. It should be noted that limiting the viscosity of the fluorescent shielding adhesive when removing fluorescence from paper is primarily to ensure good fluidity, allowing for uniform penetration into the paper and effective performance. Excessive viscosity leads to poor fluidity and insufficient penetration into the paper, thus affecting the fluorescent shielding effect. Lower viscosity allows for better penetration and more thorough contact with fibers, resulting in a better fluorescent shielding effect. Furthermore, viscosity also affects the drying speed of the adhesive on the paper surface. Excessive viscosity results in slow drying, impacting paper processing and use. Therefore, when selecting a fluorescent shielding adhesive, the appropriate viscosity should be chosen based on factors such as paper type, thickness, and processing requirements to ensure effective fluorescent shielding and maintain paper quality and performance.

[0033] Specifically, the fluorescent shielding adhesive described in this application comprises the following components: an adhesive, a mixture of diethylene glycol diethyl ether and benzotriazole. Specifically, the mass ratio of the diethylene glycol diethyl ether to the adhesive is 5%-15%, and the mass ratio of the benzotriazole mixture to the adhesive is 5%-15%.

[0034] It should be noted that each part of the adhesive solution comprises the following components by weight: 5-12 parts polyvinyl alcohol (PVA1799), 1-3 parts urea, 0.3-0.8 parts wet strength agent concentrate, 0.03-0.3 parts melamine, and 87-95 parts water. More specifically, each part of the adhesive solution comprises the following components by weight: 5-10 parts polyvinyl alcohol, 1-2 parts urea, 0.5-0.6 parts wet strength agent concentrate, 0.05-0.2 parts melamine, and 88.5-93.45 parts water.

[0035] It should be noted that the wet strength agent stock solution is polyamide epichlorohydrin resin, the mass fraction of the diethylene glycol diethyl ether is 95%-99%, and the mass fraction of the benzotriazole mixture is 10%-20%.

[0036] Polyvinyl alcohol (PVA) helps improve the transparency and color vibrancy of paper. Simultaneously, PVA has adhesive properties, firmly bonding paper together. When producing printed materials such as books and magazines, using PVA as a fluorescent shielding adhesive can enhance the adhesion between papers, thereby improving the durability of the printed materials. Furthermore, PVA can protect paper from damage caused by ultraviolet radiation and oxidation, extending its lifespan; it also improves the paper's water resistance and stain resistance, making it easier to clean and maintain. However, it is important to note that when using PVA as a raw material for paper fluorescent shielding adhesives, the appropriate concentration and formulation must be selected according to the specific application scenario to avoid changes in adhesive viscosity affecting the uniformity of sizing and the fluorescent shielding effect. At the same time, it is also necessary to control parameters such as processing time and temperature to ensure that the adhesive can fully penetrate the paper and achieve the desired effect.

[0037] The diethylene glycol diethyl ether acts as a plasticizer, helping the adhesive penetrate the paper better and enhancing its softness and plasticity. This improves the paper's processing and usability, making it easier to bend and fold. Furthermore, in this embodiment, the diethylene glycol diethyl ether also acts as a solvent, helping the benzotriazole mixture dissolve and disperse better in the adhesive. This improves the stability and uniformity of the adhesive, allowing it to function more effectively. In addition, diethylene glycol diethyl ether itself acts as an adhesive, enhancing the bonding strength between paper layers. This helps improve the durability of printed materials, making them easier to preserve and use.

[0038] The benzotriazole mixture can absorb fluorescent substances in paper, thereby reducing the paper's fluorescence reaction under ultraviolet light. This effect helps improve the paper's transparency and color vibrancy. The benzotriazole mixture also acts as an antioxidant, protecting paper from oxidation and free radical damage. This helps extend the paper's lifespan and improve its durability. Furthermore, the benzotriazole mixture has antibacterial properties, inhibiting the growth and reproduction of bacteria and mold on the paper surface. This helps maintain the paper's cleanliness and hygiene, preventing mold and deterioration. However, it is important to note that when applying the benzotriazole mixture to paper fluorescent shielding adhesives, its dosage and ratio must be controlled to ensure the adhesive works effectively and avoids excessive damage to the paper.

[0039] It should be noted that the wet strength agent stock solution is a water-soluble cationic thermosetting resin, its chemical name being polyamide-polyamine-propylene oxide resin. This resin can significantly improve the dry and wet strength of paper and increase the retention rate of fine fibers and fillers. It is formaldehyde-free, extremely environmentally friendly, and widely used in tissue paper, cup base paper, fruit bag paper, offset printing paper, packaging paper, newsprint, decorative paper, and other papers requiring wet strength.

[0040] The purpose of adding wet strength agent to the fluorescent shielding adhesive is to improve the wet strength of the paper. Wet strength agents bind to fibers, allowing the paper to maintain its structural integrity and strength even when exposed to water or other solvents. Without sufficient wet strength, paper is prone to cracking or damage when subjected to moisture, pressure, or friction, rendering it unusable. Adding wet strength agents significantly improves the paper's wet strength, ensuring good integrity and usability under various conditions. Furthermore, wet strength agents also improve the paper's folding endurance, making it more resistant to folding and bending, and less prone to tearing. This is particularly beneficial for applications requiring frequent folding or use of paper.

[0041] It should be noted that the purpose of adding melamine to the fluorescent shielding adhesive in this embodiment is to improve the strength and stability of the paper. Melamine is a resin with high adhesiveness and film-forming properties, which can increase the strength and water resistance of the paper, and improve its stability and durability. Furthermore, melamine can interact with the fluorescent shielding agent to enhance the fluorescent shielding effect and improve the anti-counterfeiting performance of the paper.

[0042] It should be noted that the purpose of adding urea to the fluorescent shielding adhesive in this embodiment is to increase the stability of the adhesive. Urea can promote the mixing and dispersion of the adhesive, making the composition of the adhesive more uniform and less prone to separation, thereby maintaining the stability of the adhesive. In addition, urea can also improve the water absorption and softness of paper, which helps to improve the printability and writeability of the paper.

[0043] It can be seen that the fluorescent shielding adhesive described in this application is different from other particulate chemical coatings. The fluorescent shielding adhesive described in this application is hydrophilic. Therefore, after surface sizing treatment of synthetic fiber paper, it will not affect the paper's air permeability, surface strength, and watermark anti-counterfeiting effect under light transmission. While meeting the requirement of no fluorescent reaction for special paper, it does not affect the paper's papermaking performance and anti-counterfeiting performance, so as to better meet application needs.

[0044] Specifically, hydrophilic fluorescent shielding adhesives can form hydrogen bonds with water molecules, exhibiting good water solubility. For fibrous paper, using hydrophilic fluorescent shielding adhesives can enhance the paper's absorbency, making it softer, more breathable, and easier to wet. This adhesive helps increase the surface energy of the paper, making it easier to wet with water, thereby improving the paper's printability and writeability.

[0045] This is determined by the mechanism of action of hydrophilic fluorescent shielding adhesives. In practice, hydrophilic fluorescent shielding adhesives mainly achieve their fluorescent shielding effect through chemical reaction or physical adsorption with paper fibers. This mechanism may not have a significant negative impact on the paper's air permeability, surface strength, or the watermark anti-counterfeiting effect under transmitted light. However, it is important to note that when using hydrophilic fluorescent shielding adhesives, the optimal shielding effect can be achieved by controlling the dosage and ratio, while avoiding excessive damage to the paper. Appropriate dosage and ratio may help maintain the original properties of the paper and will not adversely affect its air permeability, surface strength, or the watermark anti-counterfeiting effect under transmitted light.

[0046] Therefore, the proportions of the components described in this application can be reasonably adjusted according to the fluorescence intensity of the synthetic fiber security paper. For example, within the range of 5.0%-10.0%, changing the mass fraction of PVA1799 relative to the total solution alters the viscosity of the shielding adhesive, reducing the penetration of the fluorescent shielding adhesive into the paper and increasing the amount of fluorescent shielding adhesive retained on the paper surface, thereby enhancing the fluorescent shielding effect of the adhesive on the paper. Similarly, within the range of 10%-20%, changing the mass fraction of the benzotriazine mixture relative to the total solution controls the overall retention of the fluorescent shielding adhesive in the paper, thereby enhancing the fluorescent shielding performance of the adhesive on the paper. Alternatively, the above components can be reasonably adjusted simultaneously to achieve the purpose of shielding the paper's fluorescence.

[0047] On the other hand, in order to prepare the above-mentioned fluorescent shielding adhesive, the embodiments of this application also provide, as follows: Figure 1 The method for preparing the fluorescent shielding adhesive shown includes the following steps:

[0048] Step S10: Add melamine, wet strength agent stock solution, polyvinyl alcohol and urea to water in proportion, heat to 90℃-95℃, stir to the preset concentration, and obtain adhesive solution.

[0049] Step S20: Under normal temperature conditions, the mixture of diethylene glycol diethyl ether and benzotriazole is mixed evenly to obtain a clear liquid;

[0050] Step S30: After cooling the adhesive solution to room temperature, mix it with the clarifying liquid and mix evenly to obtain a fluorescent shielding adhesive solution.

[0051] The preparation steps and feeding sequence of the fluorescent shielding adhesive described in this application are as follows: Based on the total solution mass calculated according to the volume of the adhesive preparation pot, first add 30%-40% water to the pot, then add melamine, wet strength agent stock solution, PVA1799, and urea in sequence. Heat to 90℃-95℃ and maintain the temperature, stirring for 1 to 2 hours to prepare a clear adhesive solution of the required concentration. Then, after the temperature drops to room temperature, uniformly add the clarified solution obtained by stirring a mixture of diethylene glycol diethyl ether and benzotriazine at room temperature for 20 minutes to the above-mentioned clear adhesive solution. Stir for another 10 to 20 minutes to complete the preparation of the fluorescent shielding adhesive solution.

[0052] After obtaining the fluorescent shielding adhesive through the above steps, this application uses existing surface sizing equipment to sizing the synthetic fibers. In practical applications, the viscosity and mass fraction of the fluorescent shielding adhesive can be adjusted according to the fluorescence brightness of different security papers. By adjusting the viscosity, the penetration of the fluorescent shielding adhesive into the paper is reduced, and the amount of fluorescent shielding adhesive retained on the paper surface is increased, thereby increasing the fluorescence shielding effect on the paper surface. By adjusting the mass fraction of the fluorescent shielding adhesive, the total amount of fluorescent shielding adhesive retained in the paper is controlled, thereby regulating the fluorescence shielding performance of the fluorescent shielding adhesive.

[0053] As can be seen, the fluorescent shielding adhesive described in this application has good dispersion performance and does not employ traditional surface coating methods using titanium dioxide as the main raw material or other particulate materials, which are not common fluorescent shielding methods used in the securities paper industry. Due to the excellent water resistance, printability, and the inks and printing processes applicable to securities printing, securities paper has special requirements for its surface properties. Using particulate chemical coatings (such as titanium dioxide, calcium carbonate, etc.) or directly adding water-based fluorescent shielding substances to the adhesive can easily affect the air permeability, surface strength, and watermark anti-counterfeiting effect of the paper after surface sizing, thus affecting printability and anti-counterfeiting performance. This application, while meeting the requirement of no fluorescent reaction in high-grade securities paper, does not negatively impact other physical and chemical properties, printability, or anti-counterfeiting performance of the paper.

[0054] The technical solution described in this application will be explained in detail below with reference to specific embodiments:

[0055] Example 1

[0056] Step S10: Add melamine, wet strength agent stock solution, polyvinyl alcohol and urea to water in proportion, heat to 90°C and stir to the preset concentration to obtain the adhesive solution; 10 parts polyvinyl alcohol, 2 parts urea, 0.6 parts wet strength agent stock solution, 0.05 parts melamine and 87.35 parts water;

[0057] Step S20: Under normal temperature conditions, the mixture of diethylene glycol diethyl ether and benzotriazole is mixed evenly to obtain a clear liquid; the mass ratio of diethylene glycol diethyl ether to the liquid is 15%, and the mass ratio of the benzotriazole mixture to the liquid is 15%.

[0058] Step S30: After cooling the adhesive solution to room temperature, mix it with the clarifying liquid and mix evenly to obtain a fluorescent shielding adhesive solution.

[0059] Example 2

[0060] Step S10: Add melamine, wet strength agent stock solution, polyvinyl alcohol and urea to water in proportion, heat to 95°C and stir to the preset concentration to obtain the adhesive solution; 8 parts polyvinyl alcohol, 2 parts urea, 0.6 parts wet strength agent stock solution, 0.2 parts melamine and 89.2 parts water;

[0061] Step S20: Under normal temperature conditions, the mixture of diethylene glycol diethyl ether and benzotriazole is mixed evenly to obtain a clear liquid; the mass ratio of diethylene glycol diethyl ether to the liquid is 10%, and the mass ratio of the benzotriazole mixture to the liquid is 10%.

[0062] Step S30: After cooling the adhesive solution to room temperature, mix it with the clarifying liquid and mix evenly to obtain a fluorescent shielding adhesive solution.

[0063] Example 3

[0064] Step S10: Add melamine, wet strength agent stock solution, polyvinyl alcohol and urea to water in proportion, heat to 92°C and stir to the preset concentration to obtain the adhesive solution; 5 parts polyvinyl alcohol, 1 part urea, 0.5 parts wet strength agent stock solution, 0.1 parts melamine and 93.4 parts water;

[0065] Step S20: Under normal temperature conditions, the mixture of diethylene glycol diethyl ether and benzotriazole is mixed evenly to obtain a clear liquid; the mass ratio of diethylene glycol diethyl ether to the liquid is 5%, and the mass ratio of the benzotriazole mixture to the liquid is 5%.

[0066] Step S30: After cooling the adhesive solution to room temperature, mix it with the clarifying liquid and mix evenly to obtain a fluorescent shielding adhesive solution.

[0067] Example 4

[0068] A spectrophotometer was used to detect the fluorescence intensity of a certain synthetic fiber paper, which ranged from 19.0 to 22.0.

[0069] Therefore, a fluorescent shielding solution with a component ratio of 11.0%-12.0% was used, and the proportion of PVA1799 component in the adhesive solution was 8.0%-9.0%.

[0070] The adhesive was applied by dip-dip sizing, with an adhesive application rate of 3.5 g / m². 2 Up to 4.5g / m 2 This can reduce the fluorescence value of paper to 8.3-9.8.

[0071] Example 5

[0072] A spectrophotometer was used to detect the fluorescence value of a certain synthetic fiber paper, which ranged from 25.0 to 28.0.

[0073] Therefore, a fluorescent shielding solution with a component ratio of 13.0%-14.0% was used, and the proportion of PVA1799 component in the adhesive solution was 9.5%-10.5%.

[0074] The adhesive was applied by dip-dip sizing, with an adhesive application rate of 4.5 g / m². 2 Up to 5.5g / m 2 This can reduce the fluorescence value of paper to 7.6-8.9.

[0075] Comparative Example 1

[0076] The preparation method of granular chemical coating 1 (titanium dioxide) is as follows: first add distilled water, start stirring, then add kaolin, porcelain clay and titanium dioxide in sequence. After stirring evenly, add adhesive and stir thoroughly before use.

[0077] The amounts of each component are as follows: 10-20 parts kaolin, 10-20 parts porcelain clay, 30-50 parts titanium dioxide, 10-25 parts adhesive, and 40-50 parts distilled water.

[0078] When used for coating paper, the coating amount is 5 g / m². 2 Up to 13g / m 2 .

[0079] Comparative Example 2

[0080] The preparation method of granular chemical coating 2 (calcium carbonate) is as follows: first add distilled water, start stirring, then add kaolin, porcelain clay and precipitated calcium carbonate (PCC) in sequence. After stirring evenly, add adhesive and stir thoroughly before use.

[0081] The amounts of each component are as follows: 10-20 parts kaolin, 10-20 parts porcelain clay, 30-50 parts precipitated calcium titanate (PCC), 10-25 parts adhesive, and 40-50 parts distilled water.

[0082] When used for coating paper, the coating amount is 5 g / m². 2 Up to 13g / m 2 .

[0083] Application Example 1

[0084] The fluorescent shielding liquids prepared in Examples 1-3 were surface coated using an impregnation roller or a coating method.

[0085] When using the dip roller method for surface coating, the fluorescent shielding liquid is first pumped into the dip tank. The tank is designed with an overflow pipeline to ensure that the shielding liquid is continuously pumped into the tank during the continuous dip operation, and the liquid in the tank continuously overflows to ensure the stability of the fluorescent shielding liquid concentration.

[0086] The coating amount of the fluorescent shielding solution is 5 g / m². 2 Up to 6g / m 2 The impregnation speed is 20 to 60 meters per minute, and the impregnation length is 1.0 to 1.8 meters. The impregnation time is 1 to 5.4 seconds. After impregnation, the paper passes through two rubber-coated press rollers arranged vertically. The linear speed of the rubber rollers is 20 to 60 meters per minute to ensure that the paper obtains a stable and uniform coating amount.

[0087] Application Example 2

[0088] The fluorescent shielding liquids prepared in Examples 1-3 were subjected to surface coating treatment using a coating method.

[0089] When applying surface sizing using a coating process, the fluorescent shielding solution is first introduced into the coating equipment, allowing it to be evenly sprayed onto the paper surface. During coating, the coating amount of the fluorescent shielding solution is 4.5 g / m². 2 Up to 5.5g / m 2 After coating, the paper passes through two rubber-coated press rollers arranged vertically. The rollers run at a linear speed of 20 to 60 meters per minute to ensure that the paper obtains a stable and uniform coating amount.

[0090] Application Example 3

[0091] The granular chemical coatings prepared in Comparative Examples 1-2 were applied to the surface of synthetic fiber paper by coating method.

[0092] Coating process: The coating material is applied to the paper substrate via a roll-type coating head, rollers, and doctor blade assembly. After drying using far-infrared ray drying, air cushion drying, and drying cylinders, the paper is finished. The roll-type coating head consists of a two-roll or three-roll combination. The coating amount is controlled by an intermittent feeding device. The coating rollers transfer the coating material onto the paper web. The amount of coating material on the paper web is determined by factors such as the affinity between the coating material and the paper web, the coating material's affinity for the coating rollers, the coating material's viscosity, the paper web's absorbency, the relative speed between the paper web and the coating rollers, and the pressure between the rollers.

[0093] Precautions during coating: Coating adaptability refers to the ability to coat well and form a uniform and smooth coating layer. To meet this requirement, all components in the coating must be fully and uniformly dispersed, and the coating concentration, viscosity, and flowability must be compatible with the type of coating machine.

[0094] Experimental Example 1

[0095] The viscosity of the fluorescent shielding liquids prepared in Examples 1-3 was tested, and the results are as follows:

[0096] The viscosity of the fluorescent shielding liquid prepared in Example 1 was 28.2 cP;

[0097] The viscosity of the fluorescent shielding liquid prepared in Example 2 was 22.4 cP;

[0098] The viscosity of the fluorescent shielding liquid prepared in Example 3 was 15.5 cP.

[0099] Experimental Example 2

[0100] The products of Examples 1-3 and Comparative Examples 1-2 were coated or glued onto synthetic fiber paper with fluorescence intensity values ​​ranging from 25.0 to 28.0, respectively. Fluorescence tests were then performed on the coated or glued paper, and the results are shown below:

[0101] The fluorescence value of the paper treated with the coating described in Comparative Example 1 was 17.5 to 20.6;

[0102] The fluorescence value of the paper treated with the coating described in Comparative Example 2 ranged from 19.2 to 23.8;

[0103] The fluorescence value of the paper using the fluorescent shielding solution described in Example 1 was 6.5 to 8.2;

[0104] The fluorescence value of the paper using the fluorescent shielding solution described in Example 2 was 11.8 to 13.3;

[0105] The fluorescence value of the paper using the fluorescent shielding liquid described in Example 3 was 15.3 to 19.7.

[0106] It can be seen that the fluorescence value of the paper treated with the fluorescent shielding agent described in the embodiments of this application is significantly reduced compared with comparative examples 1-2.

[0107] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An application of a fluorescent shielding adhesive, characterized in that, Used to shield the fluorescence of synthetic fiber paper; The fluorescent shielding adhesive solution is prepared through the following steps: Melamine, wet strength agent stock solution, polyvinyl alcohol, and urea are added to water in a certain proportion. After heating to 90℃-95℃, the mixture is stirred to a preset concentration to obtain an adhesive solution. Each part of the adhesive solution contains the following components by weight: 5-12 parts polyvinyl alcohol, 1-3 parts urea, 0.3-0.8 parts wet strength agent stock solution, 0.03-0.3 parts melamine, and 87-95 parts water. Under normal temperature conditions, a mixture of diethylene glycol diethyl ether and benzotriazole is mixed evenly to obtain a clear solution; the mass ratio of diethylene glycol diethyl ether to the solution is 5%-15%, and the mass ratio of the benzotriazole mixture to the solution is 5%-15%. After the adhesive solution is cooled to room temperature, it is mixed with the clarified liquid and mixed evenly to obtain a fluorescent shielding adhesive solution.

2. The application of the fluorescent shielding adhesive according to claim 1, characterized in that, When the fluorescent shielding adhesive is used to shield the fluorescence of synthetic fiber paper, the surface is sizing is performed by impregnation rollers or coating.

3. The application of the fluorescent shielding adhesive according to claim 1, characterized in that, When the fluorescent shielding adhesive is used to shield the fluorescence of synthetic fiber paper, the proportions of each component in the fluorescent shielding adhesive are obtained based on the initial fluorescence brightness value of the synthetic fiber paper.

4. The application of the fluorescent shielding adhesive according to claim 1, characterized in that, Each portion of the adhesive comprises the following components by weight: 5-10 parts polyvinyl alcohol, 1-2 parts urea, 0.5-0.6 parts wet strength agent stock solution, 0.05-0.2 parts melamine and 88.5-93.45 parts water.

5. The application of the fluorescent shielding adhesive according to claim 1, characterized in that, The wet strength agent stock solution is polyamide epichlorohydrin resin; The mass fraction of the diethylene glycol diethyl ether is 95%-99%; The mass fraction of the benzotriazole mixture is 10%-20%.

6. The application of the fluorescent shielding adhesive according to claim 1, characterized in that, The viscosity of the fluorescent shielding adhesive is 15cp-35cp.

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