Bio-based anti-counterfeiting filter paper and preparation method thereof

Abstract

The invention relates to the technical field of anti-counterfeiting materials, in particular to bio-based anti-counterfeiting filter paper and a preparation method thereof. The invention provides bio-based anti-counterfeiting filter paper. The bio-based anti-counterfeiting filter paper comprises a base material; the anti-counterfeiting dye layer is compounded on the base material; the anti-counterfeiting dye layer is prepared from an anti-counterfeiting dye; the anti-counterfeiting dye is prepared from the following raw materials: isocyanate, polyethylene glycol, 2, 2-dimethylolpropionic acid, ethylenediamine and hematoxylon dye. The bio-based anti-counterfeiting filter paper provided by the invention is doped with a special anti-counterfeiting dye, provides unique spectral reflection information, and has the advantages of being difficult to copy, non-toxic, long in service life and the like. Compared with anti-counterfeiting filter paper circulated at the present stage, the bio-based anti-counterfeiting filter paper provided by the invention can reduce counterfeit and shoddy products flowing into the market, reduce the use risk of customers and protect the legitimate rights and interests of the customers.

Description

Technical Field

[0001] The invention relates to the technical field of anti-counterfeiting materials, and in particular to a bio-based anti-counterfeiting filter paper and a preparation method thereof. Background Art

[0002] Anti-counterfeiting paper is a general term for paper that can prevent counterfeiting. It has marks or hidden marks (patterns, patterns, watermarks, numbers, etc.) on its surface, which is not easy to prevent forgery, counterfeiting or modification. In foreign countries, anti-counterfeiting paper is also called safety paper or confidentiality paper. Early anti-counterfeiting paper was mainly used for printing banknotes, and its use was relatively simple. With the development of science and technology and the continuous development of production technology, anti-counterfeiting paper is now widely used in various certificates, securities, etc., but less used in filters for popular consumer products. Therefore, it is imperative to develop an irreplaceable anti-counterfeiting filter paper.

[0003] From the perspective of security and low cost, pigment-based anti-counterfeiting strategies have improved security and economic rationality and have become one of the most promising methods in the field of anti-counterfeiting. In addition, organic dyes, graphene copolymers, and semiconductor nanoparticles have been used as luminescent materials, but their long-term toxicity or high cost hinder their further application.

[0004] Patent application 202211022777.9 discloses a thermochromic coating and its preparation method and use method, which mentions that 5 to 30 parts of hydroxy acrylic resin, 1 to 10 parts of fluorocarbon resin, 25 parts of solvent, 0.5 to 3 parts of polyethylene glycol, 0.25 to 1 part of light stabilizer, 0.3 to 1.8 parts of filler, and 0.5 to 5 parts of thermochromic microcapsules are mixed to prepare a color-changing coating.

[0005] Patent application 202011630298.6 discloses an environmentally friendly hematoxylin staining solution, a Papanicolaou staining solution, and a preparation method and application thereof, which mentions that the staining agent is prepared by mixing hematoxylin staining solution, compound dehydrated fixing alcohol, compound buffer solution and compound EA staining solution.

[0006] However, there is the problem that the above-mentioned prior art is complex in process and the solvent system prepared is not suitable for filter paper industry class production. Preparation method adds microcapsules as described above, can block filter paper pores, increase the initial pressure difference of base paper, have a negative impact on the air permeability of filter paper, reduce the service life of base paper, and increase customer use cost. Preparation method adds the coloring agent prepared by alcohol as described above and there is room temperature volatile, solid content is difficult to control, affects the actual addition amount in production process, and in papermaking process, workshop uses steam drying paper web, and temperature in workshop is much higher than outdoor temperature, aggravates the evaporation rate of alcohol, causes the solid content of coloring agent in use to be difficult to control, affects the amount of dye coating on filter paper base paper in normal production process. 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 a preparation method thereof.

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

[0009] Base material;

[0010] and an anti-counterfeiting dye layer composited 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-dihydroxymethylpropionic acid, ethylenediamine and hematoxylin dye.

[0012] Preferably, the substrate is a base paper, comprising a bottom layer and a surface layer bonded to each other;

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

[0014] The bottom layer is prepared from a bottom layer pulp comprising bleached hardwood pulp from a kraft process and / or bleached thermo-refined chemical mechanical 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 is prepared from a surface layer slurry including slurry a and PET fiber;

[0017] The pulp a comprises at least one of bleached coniferous wood pulp by the kraft process, 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 0.7-2D.

[0020] Preferably, the fiber specific surface area of ​​the surface layer is 5 to 15 m 2 / g, the fiber specific surface area of ​​the bottom layer is 20~45m 2 / g;

[0021] In the bio-based anti-counterfeiting filter paper, the base paper ratio is 80-200 g / m 2 , the bulk thickness is controlled to be 3.0~5.0cm 3 / g.

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

[0023] a) mixing the hematoxylin dye with the TDI-PDAa solution and emulsifying;

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

[0025] The hematoxylin wood chips are steamed and filtered, and then mixed with a mordant, distilled water, a dispersant, chitosan and Tween-80 to obtain hematoxylin dye;

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

[0027] b) mixing the emulsified solution in step a) with 2,2-dimethylolpropionic acid and reacting the mixture;

[0028] c) cooling the product solution after the reaction in step b), mixing it with ethylenediamine, and reacting it to obtain an anti-counterfeiting dye.

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

[0030] Preferably, in step b), the mass ratio of the 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 temperature is 40-50°C and the reaction time is 40-70 minutes.

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

[0035] The anti-counterfeiting dye is added into the pre-curling trough and coated onto the substrate through the curling scribing device.

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

[0037] After the coating is completed, the following steps are also included: applying glue, rolling, slitting, folding and shaping, and curing;

[0038] The coating glue includes a thermosetting phenolic resin; or the coating glue includes a mixed solution of a thermosetting phenolic resin and a thermoplastic phenolic resin; the amount of glue applied is 12 to 35 g / m 2 ;

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

[0040] The present invention provides a bio-based anti-counterfeiting filter paper, comprising: a substrate; and an anti-counterfeiting dye layer composited 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-dihydroxymethylpropionic acid, ethylenediamine and hematoxylin dye. The bio-based anti-counterfeiting filter paper provided by the present invention is doped with a special anti-counterfeiting dye, provides unique spectral reflection information, and exhibits the advantages of being difficult to copy, non-toxic and having a long life. Compared with the anti-counterfeiting filter paper currently in circulation, the bio-based anti-counterfeiting filter paper provided by the present invention can reduce the flow of counterfeit and shoddy products into the market, reduce the risk of customer use, and protect the legitimate rights and interests of customers. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The filter paper of Example 1 and the filter paper of Comparative Example 1 are aged in a UV light box for 48 hours;

[0042] Figure 2 The filter paper of Example 1 and the filter paper of Comparative Example 2 are aged in a UV light box for 48 hours. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0045] Base material;

[0046] and an anti-counterfeiting dye layer composited 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-dihydroxymethylpropionic acid, ethylenediamine and hematoxylin dye.

[0048] In certain embodiments of the present invention, the substrate is a base paper, comprising a bottom layer and a surface layer bonded to each other;

[0049] The bottom layer is prepared from a bottom layer pulp including bleached hardwood pulp from the sulfate process and / or bleached thermo-chemical mechanical pulp; in some embodiments, the bottom layer is prepared from a bottom layer pulp including bleached hardwood pulp from the sulfate process and bleached thermo-chemical mechanical pulp, and the mass ratio of the bleached hardwood pulp from the sulfate process to the bleached thermo-chemical mechanical pulp is 50-80:20-50, for example, 50:50.

[0050] The kraft bleached hardwood pulp includes at least one of Bull, Parrot, Carabin, Goldfish, Villacel and Rossell.

[0051] The surface layer is prepared from a surface layer pulp including pulp a, or from a surface layer pulp including pulp a and PET fiber; the pulp a includes at least one of kraft bleached conifer pulp, mercerized pulp and dissolving pulp.

[0052] In some embodiments of the present invention, the surface layer pulp includes pulp a and PET fiber in a mass ratio of 60 to 90: 10 to 40, such as 60: 40. In some embodiments of the present invention, the surface layer pulp includes kraft bleached conifer pulp, mercerized pulp, dissolving pulp and PET fiber in a mass ratio of 50 to 90: 0 to 20: 0 to 20: 10 to 40, such as 50 to 60: 10 to 20: 5 to 15: 20 to 30, specifically 50: 15: 10: 25.

[0053] The kraft bleached coniferous wood 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 to be 500-700 mL, such as 550 mL, 600 mL, 650 mL. The diameter of the PET fiber is 0.7-2D, such as 0.7D, 1.5D, 2D.

[0055] The freeness of the bottom slurry is controlled at 200-400 mL, such as 200 mL, 400 mL, and 250 mL.

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

[0057] The fiber specific surface area of ​​the surface layer is 5 to 15 m 2 / g, such as 7m 2 / g, 11m 2 / g, 10m 2 / g; the fiber specific surface area of ​​the bottom layer is 20~45m 2 / g, for example 42m 2 / g, 24m 2 / g, 28m 2 / g.

[0058] In the bio-based anti-counterfeiting filter paper, the base paper ratio is 80-200 g / m 2 , such as 90g / m 2 , 176g / m 2, 146g / m 2 ; Bulk thickness is controlled at 3.0~5.0cm 3 / g, such as 3.6cm 3 / g, 4.8cm 3 / g, 4.3cm 3 / g.

[0059] The base paper is made from bottom layer pulp and surface layer pulp through wet-end flow, forming and drying processes.

[0060] In certain embodiments of the present invention, the anti-counterfeiting dye layer is composited on the bottom layer of the base paper.

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

[0062] a) mixing the hematoxylin dye with the TDI-PDAa solution and emulsifying;

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

[0064] The hematoxylin wood chips are steamed and filtered, and then mixed with a mordant, distilled water, a dispersant, chitosan and Tween-80 to obtain hematoxylin dye;

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

[0066] b) mixing the emulsified solution in step a) with 2,2-dimethylolpropionic acid and reacting the mixture;

[0067] c) cooling the product solution after the reaction in step b), mixing it with ethylenediamine, and reacting it to obtain an anti-counterfeiting dye.

[0068] In step a):

[0069] The hematoxylin dye is mixed with the TDI-PDAa solution and then emulsified;

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

[0071] The hematoxylin wood chips are steamed and filtered, and then mixed with a mordant, distilled water, a dispersant, chitosan and Tween-80 to obtain hematoxylin dye;

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

[0073] The hematoxylin wood chips are obtained by crushing hematoxylin wood chips, and have a size of 30 to 60 meshes, such as 30 meshes and 60 meshes.

[0074] Before the cooking, the method further includes: cleaning. The cleaning is ultrasonic cleaning, and the cleaning time is 8 to 15 minutes, such as 10 minutes or 15 minutes. During the ultrasonic cleaning, the mass ratio of the absolute dry weight of the hematoxylin wood chips to water is 1:25 to 35, such as 1:26, 1:35, or 1:29.

[0075] The cooking temperature is 85-90°C, such as 85°C and 90°C, and the cooking time is 30-60min, such as 30min, 50min, and 60min. The mass ratio of the distilled water used in the cooking to the hematite wood chips is 25-35:1, such as 30:1.

[0076] The filtration 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 amount ratio of the mordant to the filtered solution is 3-5g:100-150mL, such as 5g:100mL, 3g:100mL, 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, such as 2 g:100 mL, 6 g:100 mL, and 4 g:100 mL.

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

[0081] The mixing is stirring and mixing. The speed of the stirring and mixing is 1000-5000 rpm and the time is 10-20 minutes.

[0082] The solid content of the hematoxylin dye is 10% to 15%, such as 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 pressure is 0.1-0.3Mpa, such as 0.2Mpa, 0.3Mpa; the temperature is 60-80°C, such as 60°C, 80°C; the time is 30-50min, such as 30min, 50min.

[0084] The mass ratio of the isocyanate to the polyethylene glycol is 40-50:50-60, such as 30:70, 50:50, 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 the TDI-PDAa solution are mixed and then emulsified.

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

[0088] The emulsification is stirring emulsification, the rotation speed is 10000-15000 rpm, such as 12000 rpm, 10000 rpm, 15000 rpm; the time is 5-10 min, such as 10 min, 5 min.

[0089] In step b):

[0090] The emulsified solution in step a) is mixed with 2,2-dimethylolpropionic acid and reacted.

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

[0092] The reaction temperature is 60-80°C, such as 74°C, 64°C, 66°C; the reaction time is 40-60 min, such as 40 min, 50 min.

[0093] In step c):

[0094] The product solution after the reaction in step b) is cooled, mixed with ethylenediamine, and reacted to obtain an anti-counterfeiting dye.

[0095] The temperature after cooling is 40-50° C., such as 50° C.; the cooling is natural cooling.

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

[0097] The reaction temperature is 40-50°C, such as 40°C, 50°C; the reaction time is 40-70 min, such as 40 min, 60 min, 50 min.

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

[0099] The anti-counterfeiting dye is added into the pre-curling trough and coated onto the substrate through the curling scribing device.

[0100] Specifically, the anti-counterfeiting dye is added into the pre-curling trough and coated onto the bottom layer of the base paper through the curling scoring device.

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

[0102] In certain embodiments of the present invention, the amount of the anti-counterfeiting dye applied is 0.2% to 0.5%, such as 0.23%, 0.35%, or 0.33%.

[0103] After the coating is completed, it also includes: applying glue, winding, slitting, folding and shaping, and curing. The functions of applying glue are: 1. Improving the strength index of filter paper to prevent damage during use; 2. Covering and protecting the anti-counterfeiting dye to prevent the anti-counterfeiting dye film from being damaged and the anti-counterfeiting effect from being deteriorated due to high temperature during the coating process. The coating glue includes thermosetting phenolic resin; or the coating glue includes a mixed solution of thermosetting phenolic resin and thermoplastic phenolic resin, and the mass ratio of thermosetting phenolic resin to thermoplastic phenolic resin is 50-80:20-50. The amount of glue applied is 12-35g / m 2 , such as 12g / m 2 , 15g / m 2 , 13g / m 2 The method of applying the glue solution is film transfer sizing.

[0104] The curing temperature is 150-180° C., such as 150° C., 170° C., 160° C.; the curing time is 10-30 min, such as 30 min, 15 min, 20 min.

[0105] The present invention has no particular limitation on the sources of the raw materials used above, and they can be generally commercially available.

[0106] In order to further illustrate the present invention, a bio-based anti-counterfeiting filter paper and a preparation method thereof provided by the present invention are described in detail below in combination 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 pulp is kraft bleached softwood pulp (moon) with a freeness of 550mL;

[0110] The bottom pulp is kraft bleached hardwood pulp (bull) with a freeness of 200 mL;

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

[0112] The base paper ratio is 90g / m 2 , the bulk thickness is controlled to 3.6cm 3 / g.

[0113] The bottom layer slurry and the surface layer slurry are passed through a wet section flow, forming, and drying process to obtain a base paper; the base paper comprises a bottom layer and a surface layer that are bonded to each other, and the fiber specific surface area of ​​the surface layer is 7m 2 / g, the fiber specific surface area of ​​the bottom layer is 42m 2 / g.

[0114] Preparation of anti-counterfeiting dyes:

[0115] 1) The hematoxylin wood chips were crushed into 30 mesh wood chips, put into ultrasonic cleaning (the mass ratio of the hematoxylin wood chips to water was 1:26) for 10 minutes, put into an 85°C reactor and steamed with distilled water (the mass ratio of the distilled water used in the steaming to the hematoxylin wood chips was 30:1) for 30 minutes, and then filtered to separate the water-insoluble solids. Add a mordant (ferrous sulfate, the mordant is used in an amount ratio of 5 g to the filtered solution: 100 mL), distilled water, a dispersant (sodium carboxymethyl cellulose, the dispersant is used in an amount ratio of 2 g to the filtered solution: 100 mL), chitosan (the chitosan is used in an amount ratio of 3 g to the filtered solution: 100 mL), and Tween-80 (the Tween-80 is used in an amount ratio of 7 g to the filtered solution: 100 mL), stir and mix (the stirring speed is 2200 rpm, and the time is 13 min), to obtain a hematoxylin dye with a solid content of 15%;

[0116] The isocyanate (isophorone diisocyanate) and polyethylene glycol (the mass ratio of isocyanate to polyethylene glycol is 30:70) are subjected to a polymerization reaction 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 TDI-PDAa solution (the mass of the TDI-PDAa solution accounts for 14% of the total dry weight of the hematoxylin dye), mix them, and stir and emulsify them at 12000 rpm for 10 minutes;

[0118] 2) mixing the emulsified solution in step 1) with 2,2-dimethylolpropionic acid (the mass ratio of the 2,2-dimethylolpropionic acid to the emulsified solution in step 1) is 1:100), and reacting at 74° C. for 40 minutes;

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

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

[0121] The anti-counterfeiting dye is added into the curling trough, and the anti-counterfeiting dye is applied to the bottom layer of the base paper through a scoring sheet with a pressure of 80 KPa, a width of 1 mm, and an interval of 2 cm (the amount of the anti-counterfeiting dye applied is 0.23%); the obtained base paper is impregnated with thermosetting phenolic resin by film transfer sizing, and the amount of the adhesive is 12 g / m 2 After rolling, slitting, folding and shaping, the paper was cured at 150°C for 30 minutes to obtain a bio-based anti-counterfeiting filter paper. It can be visually observed that the color of the bottom line changes from grayish white to pink.

[0122] Example 2

[0123] Preparation of base paper:

[0124] The surface layer slurry includes mercerized pulp and PET fiber, with a mass ratio of 60:40, the freeness of the mercerized pulp is 550mL, and the diameter of the PET fiber is 0.7D;

[0125] The bottom pulp comprises bleached hardwood pulp (Carabine) and bleached thermo-refined chemical mechanical pulp in a mass ratio of 50:50, and the freeness of the bottom pulp is 400 mL;

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

[0127] The base paper ratio is 176g / m 2 , the loose thickness is controlled to 4.8cm 3 / g.

[0128] The bottom layer slurry and the surface layer slurry are passed through a wet section flow, forming, and drying process to obtain a base paper; the base paper comprises a bottom layer and a surface layer that are bonded to each other, and the fiber specific surface area of ​​the surface layer is 11m 2 / g, the fiber specific surface area of ​​the bottom layer is 24m 2 / g.

[0129] Preparation of anti-counterfeiting dyes:

[0130] 1) Crush the hematoxylin wood chips into 60 mesh chips, put them into ultrasonic cleaning (the mass ratio of the hematoxylin wood chips to water is 1:35) for 10 minutes, put them into a 90°C reactor and cook them for 60 minutes, and then filter and separate the water-insoluble solids. Add mordant (ferric sulfate, the ratio of the mordant to the filtered solution is 3g:100mL), distilled water, dispersant (polyvinyl alcohol, the ratio of the dispersant to the filtered solution is 6g:100mL), chitosan (the ratio of the chitosan to the filtered solution is 5g:100mL), Tween-80 (the ratio of the Tween-80 to the filtered solution is 5g:100mL), stir and mix (the stirring speed is 4200rpm, and the time is 20min) to obtain hematoxylin dye with a solid content of 10%;

[0131] The isocyanate and polyethylene glycol (the mass ratio of isocyanate to polyethylene glycol is 50:50) are subjected to a polymerization reaction 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 TDI-PDAa solution (the mass of the TDI-PDAa solution accounts for 11% of the total dry weight of the hematoxylin dye), mix them, and stir and emulsify them at 10000 rpm for 5 minutes;

[0133] 2) mixing the emulsified solution in step 1) with 2,2-dihydroxymethylpropionic acid (the mass ratio of the 2,2-dihydroxymethylpropionic acid to the emulsified solution in step 1) is 4:100), and reacting at 64° C. for 40 minutes;

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

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

[0136] The anti-counterfeiting dye is added into the curling trough, and the anti-counterfeiting dye is applied to the bottom layer of the base paper through a scoring sheet with a pressure of 150 KPa, a width of 2 mm, and an interval of 10 cm (the amount of the anti-counterfeiting dye applied is 0.35%); the obtained base paper is impregnated with thermosetting phenolic resin by film transfer sizing, and the amount of the adhesive is 15 g / m 2 After rolling, slitting, folding and shaping, the paper was cured at 170°C for 15 minutes to obtain the bio-based anti-counterfeiting filter paper. It can be visually observed that the color of the bottom line changes from grayish white to rose red.

[0137] Example 3

[0138] Preparation of base paper:

[0139] The surface pulp includes bleached coniferous wood pulp (Northern Lights), mercerized pulp, dissolving pulp and PET fiber, with a mass ratio of 50:15:10:25, the freeness of bleached coniferous wood pulp is 550mL, the freeness of mercerized pulp is 650mL, the freeness of dissolving pulp is 600mL, and the diameter of PPET fiber is 2D;

[0140] The bottom pulp includes bleached hardwood kraft pulp (Villacel) and bleached thermo-refined chemical mechanical pulp in a mass ratio of 20:80, wherein the freeness of the bleached hardwood kraft pulp is 250 mL, and the freeness of the bleached thermo-refined chemical mechanical pulp is 400 mL;

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

[0142] The base paper ratio is 146g / m 2 , the bulk thickness is controlled to 4.3cm 3 / g.

[0143] The bottom layer slurry and the surface layer slurry are passed through a wet section flow, forming, and drying process to obtain a base paper; the base paper comprises a bottom layer and a surface layer that are bonded to each other, and the fiber specific surface area of ​​the surface layer is 10m 2 / g, the fiber specific surface area of ​​the bottom layer is 28m 2 / g.

[0144] Preparation of anti-counterfeiting dyes:

[0145] 1) Crush the hematoxylin wood chips into 60 mesh chips, put them into ultrasonic cleaning (the mass ratio of the hematoxylin wood chips to water is 1:29) for 15 minutes, put them into a 90°C reactor and cook them for 50 minutes, and then filter and separate the water-insoluble solids. Add mordant (aluminum sulfate, the ratio of the mordant to the filtered solution is 3g:150mL), distilled water, dispersant (gelatin, the ratio of the dispersant to the filtered solution is 4g:100mL), chitosan (the ratio of the chitosan to the filtered solution is 5g:100mL), Tween-80 (the ratio of the Tween-80 to the filtered solution is 5g:100mL), stir and mix (stirring and mixing at a speed of 3200rpm for 15 minutes) to obtain a hematoxylin dye with a solid content of 5%;

[0146] The isocyanate and polyethylene glycol (the mass ratio of isocyanate to polyethylene glycol is 40:60) are subjected to a polymerization reaction 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 TDI-PDAa solution (the mass of the TDI-PDAa solution accounts for 13% of the total dry weight of the hematoxylin dye), mix them, and stir and emulsify them at 15000 rpm for 10 minutes;

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

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

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

[0151] The anti-counterfeiting dye is added into the curling trough, and the anti-counterfeiting dye is applied to the bottom layer of the base paper through a scoring sheet with a pressure of 100 KPa, a width of 3 mm, and an interval of 5 cm (the amount of the anti-counterfeiting dye applied is 0.33%); the obtained base paper is impregnated with thermosetting phenolic resin by film transfer sizing, and the amount of the adhesive is 13 g / m 2 After rolling, slitting, folding and shaping, the paper was cured at 160°C for 20 minutes to obtain a bio-based anti-counterfeiting filter paper. It can be visually observed that the color of the bottom line changes from grayish white to dark pink.

[0152] Comparative Example 1

[0153] The difference from Example 1 is:

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

[0155] The remaining steps are carried out according to the steps of Example 1 of the present invention to obtain the anti-counterfeiting filter paper.

[0156] The filter paper obtained in Comparative Example 1 and the filter paper obtained in Example 1 were aged in a UV light box for 48 hours, and the colors of the two were observed. Figure 1 shown. Figure 1 These are effect diagrams of the filter paper of Example 1 and the filter paper of Comparative Example 1 after aging in a UV light box for 48 hours; wherein, the left diagram is an effect diagram of the filter paper of Example 1 after aging in a UV light box for 48 hours, and the right diagram is an effect diagram of the filter paper of Comparative Example 1 after aging in a UV light box for 48 hours.

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

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

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

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

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

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

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

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

[0165]

[0166]

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

[0168] Comparative Example 2

[0169] The difference from Example 1 is:

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

[0171] The remaining steps are carried out according to the steps of Example 1 of the present invention to obtain the anti-counterfeiting filter paper.

[0172] The filter paper obtained in Comparative Example 2 and the filter paper obtained in Example 1 were aged in a UV light box for 48 hours, and their colors were observed. Figure 2 shown. Figure 2 These are effect diagrams of the filter paper of Example 1 and the filter paper of Comparative Example 2 after aging in a UV light box for 48 hours; wherein, the left diagram is an effect diagram of the filter paper of Example 1 after aging in a UV light box for 48 hours, and the right diagram is an effect diagram of the filter paper of Comparative Example 2 after aging in a UV light box for 48 hours.

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

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

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

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

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

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

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

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

[0181]

[0182]

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

[0184] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bio-based anti-counterfeiting filter paper, comprising: Base material; and an anti-counterfeiting dye layer composited 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-dihydroxymethylpropionic acid, ethylenediamine and hematoxylin dye.

2. The bio-based anti-counterfeiting filter paper according to claim 1, characterized in that: The substrate is a base paper, including a bottom layer and a surface layer bonded to each other; The anti-counterfeiting dye layer is compounded on the bottom layer of the base paper; The bottom layer is prepared from a bottom layer pulp comprising bleached hardwood pulp from a kraft process and / or bleached thermo-refined chemical mechanical pulp; The freeness of the bottom slurry is controlled at 200-400 mL.

3. The bio-based anti-counterfeiting filter paper according to claim 1, characterized in that: The surface layer is prepared from a surface layer slurry including slurry a, or is prepared from a surface layer slurry including slurry a and PET fiber; The pulp a comprises at least one of bleached coniferous wood pulp by the kraft process, mercerized pulp and dissolving pulp; The freeness of the slurry a is controlled at 500-700 mL; The diameter of the PET fiber is 0.7-2D.

4. The bio-based anti-counterfeiting filter paper according to claim 1, characterized in that: The fiber specific surface area of ​​the surface layer is 5 to 15 m 2 / g, the fiber specific surface area of ​​the bottom layer is 20~45m 2 / g; In the bio-based anti-counterfeiting filter paper, the base paper ratio is 80-200 g / m 2 , the bulk thickness is controlled to be 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 comprises the following steps: a) mixing the hematoxylin dye with the TDI-PDAa solution and emulsifying; The preparation method of the hematoxylin dye comprises the following steps: The hematoxylin wood chips are steamed and filtered, and then mixed with a mordant, distilled water, a dispersant, chitosan and Tween-80 to obtain hematoxylin dye; The TDI-PDAa solution is prepared from raw materials including isocyanate and polyethylene glycol; b) mixing the emulsified solution in step a) with 2,2-dimethylolpropionic acid and reacting the mixture; c) cooling the product solution after the reaction in step b), mixing it with ethylenediamine, and reacting it to obtain an 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 mass 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 the 2,2-dihydroxymethylpropionic acid to the emulsified solution in step a) is 1 to 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°C; The mass ratio of the ethylenediamine to the cooled product solution is 10-25:100; The reaction temperature is 40-50°C and the reaction time is 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 into the pre-curling trough and coated onto the substrate through the curling scribing device.

10. The preparation method according to claim 9, characterized in that: The curling scribing device is a curling scribing sheet, the interval is 1 to 30 cm, the width of the scribing sheet is 1 to 3 mm, and the pressure between the scribing sheet and the base paper is 80 to 200 KPa; After the coating is completed, the following steps are also included: applying glue, rolling, slitting, folding and shaping, and curing; The coating glue includes a thermosetting phenolic resin; or the coating glue includes a mixed solution of a thermosetting phenolic resin and a thermoplastic phenolic resin; the amount of glue applied is 12 to 35 g / m 2 ; The curing temperature is 150-180° C. and the curing time is 10-30 minutes.

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