A bio-based security filter paper and a method for preparing the same

Abstract

The application relates to the technical field of anti-counterfeiting materials, in particular to a bio-based anti-counterfeiting filter paper and a preparation method thereof. The application provides a bio-based anti-counterfeiting filter paper which comprises a base material and an anti-counterfeiting dye layer compounded on the base material; the anti-counterfeiting dye layer is prepared from anti-counterfeiting dyes; the anti-counterfeiting dyes are prepared from raw materials including isocyanate, polyethylene glycol, 2,2-dimethylol propionic acid, ethylenediamine and hematoxylin. The bio-based anti-counterfeiting filter paper provided by the application is doped with special anti-counterfeiting dyes, provides unique spectral reflection information, and has the advantages of being difficult to replicate, non-toxic and long service life. Compared with the anti-counterfeiting filter paper currently in circulation, the bio-based anti-counterfeiting filter paper provided by the application can reduce the inflow of fake and inferior products into the market, reduce the use risk of customers, and protect the legal rights and interests of customers.

Description

Technical Field

[0001] This invention relates to the field of anti-counterfeiting materials technology, and in particular to a bio-based anti-counterfeiting filter paper and its preparation method. Background Technology

[0002] Security paper is a general term for paper types that prevent counterfeiting. Its surface has markings or hidden features (patterns, designs, watermarks, serial numbers, etc.) that are difficult to counterfeit, forge, or alter. In other countries, security paper is also known as safety paper or confidential paper. Early security paper was mainly used for printing banknotes, with a relatively limited application. However, with technological advancements and continuous improvements in production processes, security paper is now widely used in various certificates and securities. Its application in consumer goods such as air filters is less common; therefore, developing an irreplaceable security filter paper is imperative.

[0003] From a security and cost-effectiveness perspective, pigment-based anti-counterfeiting strategies have improved both security and economic viability, making them one of the most promising methods in the field. Furthermore, organic dyes, graphene copolymers, and semiconductor nanoparticles have been used as luminescent materials, but their long-term toxicity or high cost hinders their further application.

[0004] Patent application 202211022777.9 discloses a thermochromic coating and its preparation and application methods. It mentions that the thermochromic coating is prepared by mixing 5-30 parts of hydroxyl acrylic resin, 1-10 parts of fluorocarbon resin, 25 parts of solvent, 0.5-3 parts of polyethylene glycol, 0.25-1 part of light stabilizer, 0.3-1.8 parts of filler, and 0.5-5 parts of thermochromic microcapsules.

[0005] Patent application 202011630298.6 discloses an environmentally friendly hematoxylin staining solution, Papanicolaou staining solution, and their preparation methods and applications. It mentions that a staining agent is prepared by mixing hematoxylin staining solution, compound dehydration and fixation alcohol, compound buffer solution and compound EA staining solution.

[0006] However, the aforementioned existing technologies suffer from complex processes and the unsuitability of the solvent systems used in the filter paper industry. Adding microcapsules, as described above, can clog filter paper pores, increase the initial pressure differential of the base paper, negatively impacting the filter paper's permeability, reducing its lifespan, and increasing customer costs. Furthermore, the dyes prepared by adding alcohol using these methods are highly volatile at room temperature, making it difficult to control their solid content and affecting the actual amount added during production. In the papermaking process, steam drying of the paper web occurs in workshops where temperatures are significantly higher than outdoor temperatures, further accelerating alcohol evaporation and making it difficult to control the solid content of the dye during use, thus affecting the amount of dye coated on the filter paper base paper during normal production. Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide a bio-based anti-counterfeiting filter paper and its preparation method.

[0008] This invention provides a bio-based anti-counterfeiting filter paper, comprising:

[0009] Substrate;

[0010] And an anti-counterfeiting dye layer laminated on the substrate;

[0011] The anti-counterfeiting dye layer is prepared from anti-counterfeiting dye; the anti-counterfeiting dye is prepared from raw materials including isocyanate, polyethylene glycol, 2,2-dimethylolpropionic acid, ethylenediamine and hematoxylin and argyrochrome dye.

[0012] Preferably, the substrate is a base paper, comprising a bottom layer and a top layer that are bonded together;

[0013] The anti-counterfeiting dye layer is laminated to the bottom layer of the base paper;

[0014] The substrate is prepared from a substrate pulp comprising sulfate-bleached hardwood pulp and / or bleached thermomechanical pulp;

[0015] The freeness of the bottom slurry is controlled at 200-400 mL.

[0016] Preferably, the surface layer is prepared from a surface layer slurry including slurry a, or from a surface layer slurry including slurry a and PET fibers;

[0017] The pulp a includes at least one of sulfate bleached softwood pulp, mercerized pulp and dissolving pulp;

[0018] The freeness of the slurry a is controlled at 500-700 mL;

[0019] The diameter of the PET fiber is 0.7 to 2D.

[0020] Preferably, the fiber specific surface area of ​​the surface layer is 5-15 m². 2 / g, the specific surface area of ​​the bottom layer fibers is 20-45m². 2 / g;

[0021] In the aforementioned bio-based anti-counterfeiting filter paper, the basis weight of the base paper formulation is 80–200 g / m³. 2 The loose thickness should be controlled between 3.0 and 5.0 cm. 3 / g.

[0022] Preferably, the method for preparing the anti-counterfeiting dye includes the following steps:

[0023] a) The hematoxylin dye is mixed with the TDI-PDAa solution and then emulsified;

[0024] The preparation method of the hematoxylin dye includes the following steps:

[0025] After steaming and filtering, the sappanwood chips are mixed with mordant, distilled water, dispersant, chitosan and Tween-80 to obtain sappanwood dye.

[0026] The TDI-PDAa solution is prepared from raw materials including isocyanate and polyethylene glycol;

[0027] b) Mix the emulsified solution from step a) with 2,2-dimethylolpropionic acid and then react;

[0028] c) After cooling the product solution from step b), mix it with ethylenediamine and react to obtain the anti-counterfeiting dye.

[0029] Preferably, in step a), the mass of the TDI-PDAa solution accounts for 10% to 15% of the total dry weight of the hematoxylin dye.

[0030] Preferably, in step b), the mass ratio of 2,2-dihydroxymethylpropionic acid to the emulsified solution in step a) is 1 to 4:100.

[0031] Preferably, in step c), the temperature after cooling is 40–50°C;

[0032] The mass ratio of the ethylenediamine to the cooled product solution is 10-25:100;

[0033] The reaction is carried out at a temperature of 40–50°C for a time of 40–70 min.

[0034] This invention also provides a method for preparing the bio-based anti-counterfeiting filter paper described above, comprising the following steps:

[0035] The anti-counterfeiting dye is added to the pre-coiling material tank and then applied to the substrate through the curling and marking device.

[0036] Preferably, the curling scribing device is a curling scribing sheet with a spacing of 1 to 30 cm, a scribing sheet width of 1 to 3 mm, and a pressure of 80 to 200 kPa between the scribing sheet and the base paper;

[0037] After the coating is completed, the process also includes: applying adhesive, rolling up, slitting, folding and shaping, and curing.

[0038] The coating adhesive comprises a thermosetting phenolic resin; or the coating adhesive comprises a mixed solution of thermosetting phenolic resin and thermoplastic phenolic resin; the coating amount is 12-35 g / m². 2 ;

[0039] The curing temperature is 150–180°C, and the time is 10–30 minutes.

[0040] This invention provides a bio-based anti-counterfeiting filter paper, comprising: a substrate; and an anti-counterfeiting dye layer laminated on the substrate; the anti-counterfeiting dye layer is prepared from an anti-counterfeiting dye; the anti-counterfeiting dye is prepared from raw materials including isocyanate, polyethylene glycol, 2,2-dimethylolpropionic acid, ethylenediamine, and hematoxylin and argyrochrome. The bio-based anti-counterfeiting filter paper provided by this invention is doped with a special anti-counterfeiting dye, providing unique spectral reflectance information and exhibiting advantages such as being difficult to replicate, non-toxic, and having a long lifespan. Compared to currently circulating anti-counterfeiting filter papers, the bio-based anti-counterfeiting filter paper provided by this invention can reduce the influx of counterfeit and substandard products into the market, reduce customer usage risks, and protect customers' legitimate rights and interests. Attached Figure Description

[0041] Figure 1 The images show the effects of aging the filter paper of Example 1 and the filter paper of Comparative Example 1 in a UV lamp box for 48 hours.

[0042] Figure 2 The images show the effects of the filter paper from Example 1 and Comparative Example 2 after aging in a UV lamp box for 48 hours. Detailed Implementation

[0043] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] This invention provides a bio-based anti-counterfeiting filter paper, comprising:

[0045] Substrate;

[0046] And an anti-counterfeiting dye layer laminated on the substrate;

[0047] The anti-counterfeiting dye layer is prepared from anti-counterfeiting dye; the anti-counterfeiting dye is prepared from raw materials including isocyanate, polyethylene glycol, 2,2-dimethylolpropionic acid, ethylenediamine and hematoxylin and argyrochrome dye.

[0048] In some embodiments of the present invention, the substrate is a base paper, comprising a bottom layer and a top layer that are bonded together;

[0049] The underlayer is prepared from an underlayer pulp comprising sulfate-bleached hardwood pulp and / or bleached thermomechanical pulp; in some embodiments, the underlayer is prepared from an underlayer pulp comprising sulfate-bleached hardwood pulp and bleached thermomechanical pulp, wherein the mass ratio of sulfate-bleached hardwood pulp to bleached thermomechanical pulp is 50-80:20-50, for example, 50:50.

[0050] The sulfate-bleached hardwood pulp includes at least one of Bull, Parrot, Carabin, Goldfish, Villaselle, and Rosey.

[0051] The surface layer is prepared from a surface layer slurry including slurry a, or from a surface layer slurry including slurry a and PET fibers; slurry a includes at least one of sulfate bleached softwood pulp, mercerized pulp and dissolving pulp.

[0052] In some embodiments of the present invention, the surface slurry comprises slurry a and PET fibers in a mass ratio of 60–90:10–40, for example, 60:40. In some embodiments of the present invention, the surface slurry comprises sulfate-bleached softwood pulp, mercerizing pulp, dissolving pulp, and PET fibers in a mass ratio of 50–90:0–20:0–20:10–40, for example, 50–60:10–20:5–15:20–30, specifically, 50:15:10:25.

[0053] The sulfate-bleached softwood pulp includes at least one of Moon, Silver Star, LAJA, Northern Lights, Kelly, Northwood, and Blue Forest.

[0054] The freeness of the slurry a is controlled at 500-700 mL, for example, 550 mL, 600 mL, or 650 mL. The diameter of the PET fiber is 0.7-2D, for example, 0.7D, 1.5D, or 2D.

[0055] The freeness of the bottom slurry is controlled between 200 and 400 mL, for example, 200 mL, 400 mL, or 250 mL.

[0056] The mass ratio of the surface layer slurry to the bottom layer slurry is 50-70:30-50, for example, 70:30, 60:40, or 50:50.

[0057] The surface layer has a fiber specific surface area of ​​5-15 m². 2 / g, for example, 7m 2 / g、11m 2 / g, 10m 2 / g; the specific surface area of ​​the bottom layer fibers is 20-45m². 2 / g, for example, 42m 2 / g、24m 2 / g、28m 2 / g.

[0058] In the aforementioned bio-based anti-counterfeiting filter paper, the basis weight of the base paper formulation is 80–200 g / m³. 2 For example, 90g / m 2 176g / m 2146g / m 2 The looseness should be controlled at 3.0–5.0 cm. 3 / g, for example, 3.6cm 3 / g, 4.8cm 3 / g, 4.3cm 3 / g.

[0059] The base paper is made from a bottom layer slurry and a top layer slurry through a wet-end flow, forming, and drying process.

[0060] In some embodiments of the present invention, the anti-counterfeiting dye layer is laminated to the bottom layer of the base paper.

[0061] In some embodiments of the present invention, the method for preparing the anti-counterfeiting dye includes the following steps:

[0062] a) The hematoxylin dye is mixed with the TDI-PDAa solution and then emulsified;

[0063] The preparation method of the hematoxylin dye includes the following steps:

[0064] After steaming and filtering, the sappanwood chips are mixed with mordant, distilled water, dispersant, chitosan and Tween-80 to obtain sappanwood dye.

[0065] The TDI-PDAa solution is prepared from raw materials including isocyanate and polyethylene glycol;

[0066] b) Mix the emulsified solution from step a) with 2,2-dimethylolpropionic acid and then react;

[0067] c) After cooling the product solution from step b), mix it with ethylenediamine and react to obtain the anti-counterfeiting dye.

[0068] In step a):

[0069] The hematoxylin dye was mixed with TDI-PDAa solution and then emulsified.

[0070] The preparation method of the hematoxylin dye includes the following steps:

[0071] After steaming and filtering, the sappanwood chips are mixed with mordant, distilled water, dispersant, chitosan and Tween-80 to obtain sappanwood dye.

[0072] The TDI-PDAa solution is prepared from raw materials including isocyanate and polyethylene glycol.

[0073] The sappanwood chips are obtained by crushing sappanwood chips, with a size of 30 to 60 mesh, such as 30 mesh or 60 mesh.

[0074] Before steaming, the process also includes cleaning. The cleaning is ultrasonic cleaning, and the cleaning time is 8–15 minutes, for example, 10 minutes or 15 minutes. During the ultrasonic cleaning, the mass ratio of the oven-dry weight of the sappanwood chips to the water is 1:25–35, for example, 1:26, 1:35, or 1:29.

[0075] The cooking temperature is 85–90°C, for example, 85°C or 90°C; the time is 30–60 minutes, for example, 30 minutes, 50 minutes, or 60 minutes. The mass ratio of distilled water to the sappanwood chips used in the cooking process is 25–35:1, for example, 30:1.

[0076] The filter is used to separate water-insoluble solids.

[0077] The mordant is selected from at least one of ferrous sulfate, ferric sulfate, and aluminum sulfate. The ratio of the mordant to the filtered solution is 3-5g:100-150mL, for example, 5g:100mL, 3g:100mL, or 3g:150mL.

[0078] The distilled water is used to control the solid content of the obtained hematoxylin dye.

[0079] The dispersant is selected from at least one of gelatin, sodium carboxymethyl cellulose, polyvinyl alcohol, and sodium polycarboxylate. The ratio of the dispersant to the filtered solution is 2–10 g:100 mL, for example, 2 g:100 mL, 6 g:100 mL, or 4 g:100 mL.

[0080] The mass ratio of chitosan to Tween-80 is 3-5:5-7, for example, 3:7 or 5:5. The ratio of the total mass of chitosan and Tween-80 to the volume of the filtered solution is 3-10 g:100 mL, for example, 10 g:100 mL.

[0081] The mixing is a stirring mixture. The stirring speed is 1000-5000 rpm, and the time is 10-20 min.

[0082] The solid content of the sappanwood dye is 10% to 15%, for example, 15% or 10%.

[0083] The TDI-PDAa solution is prepared from raw materials including isocyanate and polyethylene glycol. Specifically, the TDI-PDAa solution is obtained by polymerization of isocyanate and polyethylene glycol. The polymerization reaction is carried out at a pressure of 0.1–0.3 MPa, such as 0.2 MPa or 0.3 MPa; at a temperature of 60–80°C, such as 60°C or 80°C; and for a time of 30–50 min, such as 30 min or 50 min.

[0084] The mass ratio of isocyanate to polyethylene glycol is 40-50:50-60, for example, 30:70, 50:50, or 40:60.

[0085] The isocyanate includes isophorone diisocyanate and / or tetramethyl dimethylphenyl diisocyanate.

[0086] After obtaining the hematoxylin dye and TDI-PDAa solution, the hematoxylin dye and TDI-PDAa solution are mixed and then emulsified.

[0087] The TDI-PDAa solution accounts for 10% to 15% of the total dry weight of the hematoxylin dye, for example, 14%, 11%, or 13%.

[0088] The emulsification is performed by stirring, with a rotation speed of 10,000 to 15,000 rpm, such as 12,000 rpm, 10,000 rpm, or 15,000 rpm; and a time of 5 to 10 minutes, such as 10 minutes or 5 minutes.

[0089] In step b):

[0090] The emulsified solution from step a) was mixed with 2,2-dimethylolpropionic acid and then reacted.

[0091] The mass ratio of the 2,2-dihydroxymethylpropionic acid to the emulsified solution of step a) is 1 to 4:100; for example, 1:100, 4:100, 2:100.

[0092] The reaction temperature is 60–80°C, for example 74°C, 64°C, or 66°C; the time is 40–60 min, for example 40 min or 50 min.

[0093] In step c):

[0094] After cooling the product solution from step b), it is mixed with ethylenediamine and reacted to obtain the anti-counterfeiting dye.

[0095] The temperature after cooling is 40-50℃, for example, 50℃; the cooling is natural cooling.

[0096] The mass ratio of the ethylenediamine to the cooled product solution is 10 to 25:100; for example, 10:100 or 25:100.

[0097] The reaction temperature is 40–50°C, for example, 40°C or 50°C; the time is 40–70 min, for example, 40 min, 60 min, or 50 min.

[0098] This invention also provides a method for preparing the bio-based anti-counterfeiting filter paper described above, comprising the following steps:

[0099] The anti-counterfeiting dye is added to the pre-coiling material tank and then applied to the substrate through the curling and marking device.

[0100] Specifically, the anti-counterfeiting dye is added to the pre-coiling material tank and then applied to the bottom layer of the base paper using a curling and marking device.

[0101] The curling scribing device consists of curled scribing sheets with an interval of 1 to 30 cm, such as 2 cm, 10 cm, or 5 cm; the scribing sheet width is 1 to 3 mm, such as 1 mm, 2 mm, or 3 mm; and the pressure between the scribing sheet and the base paper is 80 to 200 kPa, such as 80 kPa, 150 kPa, or 100 kPa.

[0102] In some embodiments of the present invention, the amount of adhesive applied to the anti-counterfeiting dye is 0.2% to 0.5%; for example, 0.23%, 0.35%, or 0.33%.

[0103] After coating, the process also includes: applying the adhesive, winding, slitting, folding and shaping, and curing. The function of the adhesive is: 1. to improve the strength of the filter paper and prevent damage during use; 2. to cover and protect the anti-counterfeiting dye, preventing damage to the anti-counterfeiting dye film and a decrease in anti-counterfeiting effect due to high temperature during the adhesive application process. The adhesive used for coating includes thermosetting phenolic resin; or the adhesive used for coating includes a mixed solution of thermosetting phenolic resin and thermoplastic phenolic resin, wherein the mass ratio of the thermosetting phenolic resin to the thermoplastic phenolic resin is 50-80:20-50. The amount of adhesive applied is 12-35 g / m³. 2 For example, 12g / m 2 15g / m 2 13g / m 2 The method for applying the adhesive is film transfer application.

[0104] The curing temperature is 150-180℃, such as 150℃, 170℃, or 160℃; the curing time is 10-30 minutes, such as 30 minutes, 15 minutes, or 20 minutes.

[0105] The present invention does not impose any special restrictions on the source of the raw materials used above, and they can be commercially available.

[0106] To further illustrate the present invention, the following detailed description of a bio-based anti-counterfeiting filter paper and its preparation method provided by the present invention is provided in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0107] Example 1

[0108] Preparation of base paper:

[0109] The surface slurry is sulfate-bleached softwood pulp (Moon) with a freeness of 550 mL;

[0110] The bottom layer pulp is sulfate-bleached hardwood pulp (Bull) with a freeness of 200 mL;

[0111] The mass ratio of the surface layer slurry to the bottom layer slurry is 70:30;

[0112] The basis weight of the base paper is 90 g / m³. 2 The porosity is controlled at 3.6cm. 3 / g.

[0113] The base paper is prepared by wet-end flow, forming, and drying of the bottom layer slurry and the top layer slurry; the base paper comprises a bottom layer and a top layer bonded together, and the fiber specific surface area of ​​the top layer is 7m². 2 / g, the specific surface area of ​​the bottom fiber is 42m². 2 / g.

[0114] Preparation of anti-counterfeiting dyes:

[0115] 1) Crush the sappanwood chips into 30-mesh chips, put them into ultrasonic cleaning (the dry weight of the sappanwood chips to the mass ratio of water is 1:26) for 10 minutes, then put them into an 85°C reactor and cook them with distilled water (the mass ratio of distilled water to the sappanwood chips is 30:1) for 30 minutes. After that, filter to separate the water-insoluble solids. Add mordant (ferrous sulfate, the ratio of mordant to the filtered solution is 5g:100mL), distilled water, dispersant (sodium carboxymethyl cellulose, the ratio of dispersant to the filtered solution is 2g:100mL), chitosan (the ratio of chitosan to the filtered solution is 3g:100mL), and Tween-80 (the ratio of Tween-80 to the filtered solution is 7g:100mL), and stir to mix (stirring speed is 2200rpm, time is 13min) to obtain a hematoxylin dye with a solid content of 15%.

[0116] Isocyanate (isophorone diisocyanate) and polyethylene glycol (isocyanate and polyethylene glycol in a mass ratio of 30:70) were polymerized at a pressure of 0.2 MPa, a temperature of 60 °C, and a time of 30 min to obtain a TDI-PDAa solution.

[0117] Weigh the hematoxylin dye and mix it with TDI-PDAa solution (the mass of TDI-PDAa solution accounts for 14% of the total dry weight of the hematoxylin dye), and then stir and emulsify at 12000 rpm for 10 min.

[0118] 2) Mix the emulsified solution from step 1) with 2,2-dimethylolpropionic acid (the mass ratio of 2,2-dimethylolpropionic acid to the emulsified solution from step 1) is 1:100) and react at 74°C for 40 min.

[0119] 3) After the product solution from step 2) is naturally cooled to 40°C, it is mixed with ethylenediamine (the mass ratio of ethylenediamine to the cooled product solution is 10:100) and reacted at 40°C for 40 minutes to obtain the anti-counterfeiting dye.

[0120] Preparation of bio-based anti-counterfeiting filter paper:

[0121] The anti-counterfeiting dye is added to a curling trough, and then applied to the base paper substrate using a scribing tool with a pressure of 80 kPa, a width of 1 mm, and a spacing of 2 cm (the amount of anti-counterfeiting dye applied is 0.23%). The resulting base paper is then impregnated with thermosetting phenolic resin using a film transfer sizing method, with an application rate of 12 g / m³. 2 After winding, slitting, folding, and shaping, the paper is cured at 150℃ for 30 minutes to obtain bio-based anti-counterfeiting filter paper. Visually, the color of the bottom scribbled lines changes from grayish-white to pink.

[0122] Example 2

[0123] Preparation of base paper:

[0124] The surface layer sizing material consists of mercerizing paste and PET fibers in a mass ratio of 60:40. The mercerizing paste has a freeness of 550 mL, and the PET fibers have a diameter of 0.7 D.

[0125] The base slurry consists of sulfate-bleached hardwood pulp (carabin) and bleached thermomechanical pulp in a mass ratio of 50:50, and the freeness of the base slurry is 400 mL.

[0126] The mass ratio of the surface layer slurry to the bottom layer slurry is 60:40;

[0127] The basis weight of the base paper is 176 g / m³. 2 The porosity is controlled at 4.8cm. 3 / g.

[0128] The base paper is prepared by wet-end flow, forming, and drying of the bottom layer slurry and the top layer slurry; the base paper comprises a bottom layer and a top layer bonded together, and the fiber specific surface area of ​​the top layer is 11 m². 2 / g, the specific surface area of ​​the bottom fiber is 24m². 2 / g.

[0129] Preparation of anti-counterfeiting dyes:

[0130] 1) Crush sappanwood chips into 60-mesh chips, ultrasonically clean them (the dry weight of the sappanwood chips to the water mass ratio is 1:35) for 10 minutes, then cook them in a 90℃ reactor for 60 minutes. Filter to separate the water-insoluble solids. Add mordant (ferric sulfate, the ratio of mordant to the filtered solution is 3g:100mL), distilled water, dispersant (polyvinyl alcohol, the ratio of dispersant to the filtered solution is 6g:100mL), chitosan (the ratio of chitosan to the filtered solution is 5g:100mL), and Tween-80 (the ratio of Tween-80 to the filtered solution is 5g:100mL). Stir and mix (stirring speed is 4200rpm, time is 20min) to obtain a sappanwood dye with a solid content of 10%.

[0131] Isocyanate and polyethylene glycol (mass ratio of isocyanate to polyethylene glycol is 50:50) were polymerized at a pressure of 0.3 MPa, a temperature of 80 °C, and a time of 50 min to obtain a TDI-PDAa solution.

[0132] Weigh the hematoxylin dye and mix it with TDI-PDAa solution (the mass of TDI-PDAa solution accounts for 11% of the total dry weight of the hematoxylin dye), and then stir and emulsify at 10000 rpm for 5 min.

[0133] 2) Mix the emulsified solution from step 1) with 2,2-dimethylolpropionic acid (the mass ratio of 2,2-dimethylolpropionic acid to the emulsified solution from step 1) is 4:100) and react at 64°C for 40 min.

[0134] 3) After the product solution from step 2) is naturally cooled to 50°C, it is mixed with ethylenediamine (the mass ratio of ethylenediamine to the cooled product solution is 25:100) and reacted at 50°C for 60 minutes to obtain the anti-counterfeiting dye.

[0135] Preparation of bio-based anti-counterfeiting filter paper:

[0136] The anti-counterfeiting dye is added to a curling trough, and then applied to the base paper substrate using a scribing tool with a pressure of 150 kPa, a width of 2 mm, and a spacing of 10 cm (the amount of anti-counterfeiting dye applied is 0.35%). The resulting base paper is then impregnated with thermosetting phenolic resin using a film transfer sizing method, with an application rate of 15 g / m³. 2 After winding, slitting, folding, and shaping, the paper is cured at 170℃ for 15 minutes to obtain bio-based anti-counterfeiting filter paper. Visually, the color of the bottom scribbled line changes from grayish-white to rose-red.

[0137] Example 3

[0138] Preparation of base paper:

[0139] The surface slurry consists of sulfate-bleached softwood pulp (Aurora), mercerized pulp, dissolving pulp, and PET fibers in a mass ratio of 50:15:10:25. The freeness of the sulfate-bleached softwood pulp is 550 mL, the freeness of the mercerized pulp is 650 mL, the freeness of the dissolving pulp is 600 mL, and the diameter of the PET fibers is 2D.

[0140] The bottom layer pulp consists of sulfate-bleached hardwood pulp (Villacell) and bleached thermomechanical pulp in a mass ratio of 20:80. The freeness of the sulfate-bleached hardwood pulp is 250 mL, and the freeness of the bleached thermomechanical pulp is 400 mL.

[0141] The mass ratio of the surface layer slurry to the bottom layer slurry is 50:50;

[0142] The basis weight of the base paper formulation is 146 g / m³. 2 The porosity is controlled at 4.3cm. 3 / g.

[0143] The base paper is prepared by wet-end flow, forming, and drying of the bottom layer slurry and the top layer slurry; the base paper comprises a bottom layer and a top layer bonded together, and the fiber specific surface area of ​​the top layer is 10m². 2 / g, the specific surface area of ​​the bottom fiber is 28m². 2 / g.

[0144] Preparation of anti-counterfeiting dyes:

[0145] 1) Crush sappanwood chips into 60-mesh chips, ultrasonically clean them (the dry weight of the sappanwood chips to the water mass ratio is 1:29) for 15 minutes, then cook them in a 90℃ reactor for 50 minutes. Filter to separate the water-insoluble solids. Add mordant (aluminum sulfate, the ratio of mordant to the filtered solution is 3g:150mL), distilled water, dispersant (gelatin, the ratio of dispersant to the filtered solution is 4g:100mL), chitosan (the ratio of chitosan to the filtered solution is 5g:100mL), and Tween-80 (the ratio of Tween-80 to the filtered solution is 5g:100mL). Stir and mix (stirring speed is 3200rpm for 15 minutes) to obtain a sappanwood dye with a solid content of 5%.

[0146] Isocyanate and polyethylene glycol (mass ratio of isocyanate to polyethylene glycol is 40:60) were polymerized at a pressure of 0.2 MPa, a temperature of 70 °C, and a time of 40 min to obtain a TDI-PDAa solution.

[0147] Weigh the hematoxylin dye and mix it with TDI-PDAa solution (the mass of TDI-PDAa solution accounts for 13% of the total dry weight of the hematoxylin dye), and then stir and emulsify at 15000 rpm for 10 min.

[0148] 2) Mix the emulsified solution from step 1) with 2,2-dimethylolpropionic acid (the mass ratio of 2,2-dimethylolpropionic acid to the emulsified solution from step 1) is 2:100) and react at 66°C for 50 min.

[0149] 3) After the product solution from step 2) is naturally cooled to 50°C, it is mixed with ethylenediamine (the mass ratio of ethylenediamine to the cooled product solution is 25:100) and reacted at 50°C for 50 minutes to obtain the anti-counterfeiting dye.

[0150] Preparation of bio-based anti-counterfeiting filter paper:

[0151] The anti-counterfeiting dye was added to a curling trough, and then applied to the base paper substrate using a scribing tool with a pressure of 100 kPa, a width of 3 mm, and a spacing of 5 cm (the amount of anti-counterfeiting dye applied was 0.33%). The resulting base paper was then impregnated with thermosetting phenolic resin using a film transfer sizing method, with an application rate of 13 g / m³. 2 After winding, slitting, folding, and shaping, the paper is cured at 160℃ for 20 minutes to obtain bio-based anti-counterfeiting filter paper. Visually, the color of the bottom scribbled lines changes from grayish-white to dark pink.

[0152] Comparative Example 1

[0153] The difference from Example 1 is as follows:

[0154] The anti-counterfeiting dye was replaced with a common polyphenolic natural dye: rhubarb.

[0155] The remaining steps are performed in accordance with the steps of Embodiment 1 of the present invention to obtain anti-counterfeiting filter paper.

[0156] After aging the filter paper obtained in Comparative Example 1 and the filter paper obtained in Example 1 in a UV lamp box for 48 hours, their colors were observed. Figure 1 As shown. Figure 1 The images show the effects of the filter paper of Example 1 and the filter paper of Comparative Example 1 after aging in a UV lamp box for 48 hours; the left image shows the effect of the filter paper of Example 1 after aging in a UV lamp box for 48 hours, and the right image shows the effect of the filter paper of Comparative Example 1 after aging in a UV lamp box for 48 hours.

[0157] The performance of the aged filter paper was tested, and the results are shown in Table 1. The standards and instruments used for some of the testing are as follows:

[0158] Quantitative sampling: GB / T 451.2-2002, quantitative sampler ZB-DLD100;

[0159] Thickness: GB / T24218.2-2009, Digital display thickness gauge ZBH-4;

[0160] Stiffness: GB / T22364-2008, DRK106 crease stiffness tester;

[0161] Air permeability: GB / T 5453-1997, Digital air permeability meter YG461E;

[0162] Bursting strength: GB / T454-2002, Paper bursting strength tester DRK109B;

[0163] Flexural endurance: GB / T 457-2002, flexural endurance tester ZB-NZ135A.

[0164] Table 1 Performance test results of filter paper after aging

[0165]

[0166]

[0167] Experimental results show that, under the same treatment conditions, the color aging resistance of Comparative Example 1 is worse than that of Example 1; and the strength and folding endurance of Comparative Example 1 are reduced by about 10% compared with Example 1.

[0168] Comparative Example 2

[0169] The difference from Example 1 is as follows:

[0170] The anti-counterfeiting dye was replaced with a conventional azo dye: Congo Red.

[0171] The remaining steps are performed in accordance with the steps of Embodiment 1 of the present invention to obtain anti-counterfeiting filter paper.

[0172] After aging the filter paper obtained in Comparative Example 2 and the filter paper obtained in Example 1 in a UV lamp box for 48 hours, their colors were observed. Figure 2 As shown. Figure 2 The images show the effects of the filter paper of Example 1 and the filter paper of Comparative Example 2 after aging in a UV lamp box for 48 hours. The left image shows the effect of the filter paper of Example 1 after aging in a UV lamp box for 48 hours, and the right image shows the effect of the filter paper of Comparative Example 2 after aging in a UV lamp box for 48 hours.

[0173] The performance of the aged filter paper was tested, and the results are shown in Table 2. The standards and instruments used for some of the testing are as follows:

[0174] Quantitative sampling: GB / T 451.2-2002, quantitative sampler ZB-DLD100;

[0175] Thickness: GB / T24218.2-2009, Digital display thickness gauge ZBH-4;

[0176] Stiffness: GB / T22364-2008, DRK106 crease stiffness tester;

[0177] Air permeability: GB / T 5453-1997, Digital air permeability meter YG461E;

[0178] Bursting strength: GB / T454-2002, Paper bursting strength tester DRK109B;

[0179] Flexural endurance: GB / T 457-2002, flexural endurance tester ZB-NZ135A.

[0180] Table 2 Performance test results of filter paper after aging

[0181]

[0182]

[0183] Experimental results show that, under the same treatment conditions, the color aging resistance of Comparative Example 2 is worse than that of Example 1. Furthermore, the strength, folding endurance, and air permeability of Comparative Example 2 are significantly lower than those of Example 1.

[0184] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bio-based anti-counterfeiting filter paper, comprising: Substrate; And an anti-counterfeiting dye layer laminated on the substrate; The anti-counterfeiting dye layer is prepared from anti-counterfeiting dye; the anti-counterfeiting dye is prepared from raw materials including isocyanate, polyethylene glycol, 2,2-dimethylolpropionic acid, ethylenediamine and hematoxylin and argyrochrome dye.

2. The bio-based anti-counterfeiting filter paper according to claim 1, characterized in that, The substrate is a base paper, comprising a bottom layer and a top layer that are bonded together. The anti-counterfeiting dye layer is laminated to the bottom layer of the base paper; The substrate is prepared from a substrate pulp comprising sulfate-bleached hardwood pulp and / or bleached thermomechanical pulp; The freeness of the bottom slurry is controlled at 200~400 mL.

3. The bio-based anti-counterfeiting filter paper according to claim 2, characterized in that, The surface layer is prepared from a surface layer slurry including slurry a, or from a surface layer slurry including slurry a and PET fibers; The pulp a includes at least one of sulfate bleached softwood pulp, mercerized pulp and dissolving pulp; The freeness of the slurry a is controlled at 500~700 mL; The diameter of the PET fiber is 0.7~2 D.

4. The bio-based anti-counterfeiting filter paper according to claim 2, characterized in that, The surface layer has a fiber specific surface area of ​​5-15 m². 2 / g, the specific surface area of ​​the bottom layer fibers is 20~45 m² 2 / g; In the bio-based anti-counterfeiting filter paper, the basis weight of the base paper formulation is 80~200 g / m³. 2 The looseness thickness should be controlled at 3.0~5.0cm. 3 / g.

5. The bio-based anti-counterfeiting filter paper according to claim 1, characterized in that, The preparation method of the anti-counterfeiting dye includes the following steps: a) The hematoxylin dye is mixed with the TDI-PDAa solution and then emulsified; The preparation method of the hematoxylin dye includes the following steps: After steaming and filtering, the sappanwood chips are mixed with mordant, distilled water, dispersant, chitosan and Tween-80 to obtain sappanwood dye. The TDI-PDAa solution is prepared from raw materials including isocyanate and polyethylene glycol; b) Mix the emulsified solution from step a) with 2,2-dimethylolpropionic acid and then react; c) After cooling the product solution from step b), mix it with ethylenediamine and react to obtain the anti-counterfeiting dye.

6. The bio-based anti-counterfeiting filter paper according to claim 5, characterized in that, In step a), the mass of the TDI-PDAa solution accounts for 10% to 15% of the total dry weight of the hematoxylin dye.

7. The bio-based anti-counterfeiting filter paper according to claim 5, characterized in that, In step b), the mass ratio of 2,2-dihydroxymethylpropionic acid to the emulsified solution in step a) is 1~4:

100.

8. The bio-based anti-counterfeiting filter paper according to claim 5, characterized in that, In step c), the temperature after cooling is 40~50℃; The mass ratio of the ethylenediamine to the cooled product solution is 10~25:100; The reaction is carried out at a temperature of 40-50°C for a time of 40-70 minutes.

9. A method for preparing the bio-based anti-counterfeiting filter paper according to any one of claims 1 to 8, comprising the following steps: The anti-counterfeiting dye is added to the pre-coiling material tank and then applied to the substrate through the curling and marking device.

10. The preparation method according to claim 9, characterized in that, The curling scribing device is a curled scribing sheet with an interval of 1~30 cm, a scribing sheet width of 1~3 mm, and a pressure of 80~200 kPa between the scribing sheet and the base paper. After the coating is completed, the process also includes: applying adhesive, rolling up, slitting, folding and shaping, and curing. The coating adhesive comprises a thermosetting phenolic resin; or the coating adhesive comprises a mixed solution of thermosetting phenolic resin and thermoplastic phenolic resin; the coating amount is 12~35 g / m². 2 ; The curing temperature is 150~180℃ and the time is 10~30 min.

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