Surface dyeing method of colored typewriting paper

Abstract

The invention belongs to the technical field of papermaking, and particularly relates to a surface dyeing method of colored typewriting paper. Comprising the following technological processes of pulp board conveying, chain board conveying, pulper conveying, discharging pool conveying, pulping machine conveying, pulp forming pool conveying, pre-making pool conveying, pulp flushing pump conveying, pressure screen conveying, pulp flowing box conveying, net part conveying, pressing part conveying, pre-baking, sizing machine conveying, post-baking, coiling part conveying, rewinding, packaging and warehousing. The consumption of the dye is reduced, colors are attached to the surfaces of the paper sheets, the paper sheets are more gorgeous, the color density is higher, pollution is not prone to occurring, and the system scrubbing difficulty is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of papermaking, and in particular relates to a surface dyeing method for colored typing paper. Background Art

[0002] Color typing paper is a kind of paper with a basis weight of 28-30g / m 2 Thin paper is mainly used for typing, copying, printing vouchers, forms, etc. It is divided into five colors: white, red, yellow, green and blue. The paper is required to be clean, smooth and tough so that there will be no holes when typing and no scratches when copying with a hard pen. It has good water resistance and can be written with a fountain pen. The production of colored typing paper is generally dyed in the pulp. During the process of forming on the net, a lot of white water is lost, the amount of dye is large, and the paper is easy to form color difference and cause unqualified products. At the same time, the treatment of dyeing wastewater is difficult and the environment is seriously polluted. The present invention aims to develop a surface dyeing process, which is dyed in an immersion surface sizing machine. The amount of dye is reduced by 40-60% compared with the dyeing in the pulp. The dyeing is uniform, no dyeing wastewater is generated, it is friendly to the environment, and has broad application prospects. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a surface dyeing method for colored typing paper, which saves dye usage, and the color adheres to the surface of the paper, making it more vivid and having a higher color density. At the same time, it is not easy to be polluted, reducing the difficulty of system brushing.

[0004] The surface dyeing method of the colored typing paper of the present invention comprises the following process flow: pulp board→chain conveyor→pulper→discharging tank→refiner→slurry tank→pre-slurry tank→pulper pump→pressure screen→head box→wire part→pressing part→pre-drying→sizing machine→post-drying→winding part→rewinding→packaging and storage;

[0005] in,

[0006] (1) Pulp ratio: 20-30% bleached kraft softwood pulp, 80-70% bleached kraft hardwood pulp;

[0007] (2) Add light calcium carbonate to the unloading pool to improve the smoothness and surface fineness of the finished paper and improve the uniformity of the surface color.

[0008] (3) Refining: Three DD720 disc refiners are used in series for refining. The first disc refiner uses a cutting-off disc with a refining power of 420 kW; the second and third disc refiners use a debonding disc with a refining power of 350 kW each; the valve opening is 55%-60%, and the sizing flow rate is 140-160 m 3 / h; pulp quality: beating degree: 38-40°SR, wet weight 2.5-3.5g;

[0009] (4) Add cationic starch at the inlet of the pulp pump in the pulping pool to improve the retention rate of AKD, fine fibers and fillers in the pulp and the strength of the finished paper.

[0010] (5) Add amphoteric PAM dry strength agent at the inlet of the pulp pump before papermaking to form hydrogen bonds with wood pulp fibers to improve paper strength.

[0011] (6) Add AKD and CPAM retention aids after the pulp pump and before the pressure screen; AKD can improve the water resistance of the finished paper and make the pigment adhere to the surface of the paper as much as possible to achieve the purpose of bright color of the finished paper; CPAM retention aid can increase the retention rate of AKD and fine fibers in the pulp.

[0012] (7) Add polyether defoamer into the white water tank outside the machine to eliminate bubbles in the white water system and prevent paper defects.

[0013] (8) Add organic bromine fungicide into the pre-papermaking pool and the white water tank outside the machine to kill bacteria and microorganisms inside the white water system to ensure the normal operation of the paper machine.

[0014] (9) applying a surface sizing agent by an immersion sizing machine, wherein the raw materials for preparing the surface sizing agent include: oxidized corn starch, aluminum sulfate, styrene-acrylate emulsion, brightener or colored dye;

[0015] Among them, oxidized corn starch serves as a surface sizing agent and a carrier of dyes; aluminum sulfate plays a color fixing role and, as a mordant, it can chemically react with dyes to form stable compounds, so that the dyes can better adhere to the paper and improve the dyeing effect and durability; styrene-acrylate emulsion can improve the waterproof and moisture-proof properties of the finished paper, and improve the surface strength of the finished paper to prevent hair loss and powdering; the paper can be dyed with brighteners or colored dyes as needed.

[0016] (10) Paper machine operating parameters:

[0017] Adopt 1880mm fourdrinier multi-cylinder paper machine;

[0018] Basis weight: 28g / m 2 ;

[0019] Speed: 260-280m / min;

[0020] Internet concentration: 0.4%-0.5%;

[0021] Lip opening: 8-10mm;

[0022] Shaking: amplitude 15-20mm, vibration frequency 200-220 times / min;

[0023] Dryness of the exit roller: 18-20%;

[0024] Pressing pressure: 60-80 kN / m for the first press and 100-120 kN / m for the second press;

[0025] Immersion sizing machine pressure: 110-130kN / m;

[0026] Dryness of paper entering sizing machine: 93%-96%;

[0027] Paper sheet dryness out of sizing machine: 63%-65%;

[0028] Paper dryness: 94%-96%.

[0029] Preferably, the surface sizing agent preparation method is as follows: add an appropriate amount of clean water into a starch cooking tank, start the stirrer, add oxidized corn starch and aluminum sulfate, open the steam valve, heat to 95-98°C, keep warm for 15-20 minutes, then move to a starch dilution tank, add styrene-acrylate emulsion, add 55-60°C warm water, dilute to 4.5-5% solid content, pH 5.5-6.5, temperature 65-70°C; add a brightener or a colored dye into the starch dilution tank, stir evenly and move to a starch storage tank for standby use.

[0030] When the surface sizing agent is used, it is lifted from the starch storage tank to the paper machine feeding tank and pumped to the immersion sizing machine for paper dyeing.

[0031] Preferably, the dosage of light calcium carbonate is 150-180 kg / ton of paper.

[0032] Preferably, the amount of cationic starch used is 12-15 kg / ton of paper.

[0033] Preferably, the dosage of the amphoteric PAM dry strength agent is 15-20 kg / ton of paper.

[0034] Preferably, the dosage of AKD is 15-20 kg / ton of paper.

[0035] Preferably, the dosage of CPAM retention aid is 200-300 g / ton of paper.

[0036] Preferably, the dosage of the polyether defoamer is 150-200 g / ton of paper.

[0037] Preferably, the dosage of the organic bromine fungicide is 100-150 g / ton of paper.

[0038] Preferably, the amount of oxidized corn starch is 30-35 kg / ton of paper, the amount of aluminum sulfate is 5-10 kg / ton of paper, the amount of styrene-acrylate emulsion is 3-5 kg / ton of paper, and the amount of brightener or colored dye is 2.0-3.2 kg / ton of paper.

[0039] The color typing paper obtained by the present invention can be tested for color density using a spectrodensitometer, such as a Konica-Minolta spectrodensitometer FD-5.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The dyeing process is changed from intra-pulp dyeing to surface-gel dyeing, which saves dye usage, allows the color to adhere to the surface of the paper, making it more vivid and with higher color density. It is also less prone to contamination, reducing the difficulty of system brushing. DETAILED DESCRIPTION

[0042] The technical solution of the present invention will be clearly and completely described below in conjunction with embodiments.

[0043] All raw materials used in the examples are commercially available unless otherwise specified, including:

[0044] Light calcium carbonate, Zhejiang Tianshi Nanotechnology Co., Ltd.;

[0045] Cationic starch, Jiangxi Liuhe Chemical Industry Co., Ltd.;

[0046] Amphoteric PAM dry strength agent, Zhejiang Chuanhua Chemical Co., Ltd.;

[0047] AKD, Weifang Tianfang Shenghong Chemical Co., Ltd.;

[0048] CPAM retention aid, Kemira Chemical Co., Ltd.

[0049] Polyether defoamer, Jining Nantian Agricultural Science and Chemical Co., Ltd.;

[0050] Organic bromine fungicide, Zhejiang Chuanhua Chemical Co., Ltd.;

[0051] Oxidized corn starch, Jiangxi Liuhe Chemical Industry Co., Ltd.;

[0052] Styrene-acrylate emulsion, Weifang Tianfang Shenghong Chemical Co., Ltd.;

[0053] Brightener, Zhejiang Chuanhua Huayang Chemical Co., Ltd.;

[0054] Direct Red 4BS dye, Jinan Longcai Chemical Co., Ltd.

[0055] Example 1

[0056] The surface dyeing method of the colored typing paper comprises the following process flow: pulp board → chain conveyor → pulper → unloading tank → pulper → pulping tank → pre-slurry tank → pulping pump → pressure screen → head box → wire part → pressing part → front drying → sizing machine → back drying → winding part → rewinding → packaging and storage;

[0057] in,

[0058] (1) Pulp ratio: 20% bleached kraft softwood pulp, 80% bleached kraft hardwood pulp;

[0059] (2) Adding light calcium carbonate into the unloading pool, the amount of light calcium carbonate is 150kg / ton of paper;

[0060] (3) Refining: Three DD720 disc refiners are used in series for refining. The first disc refiner uses a cutting-off type of refining disc with a refining power of 420 kW; the second and third disc refiners use a debonding type of refining disc with a refining power of 350 kW each; the valve opening is 55%, and the sizing flow rate is 140 m 3 / h; pulp quality: beating degree: 38°SR, wet weight 2.5g;

[0061] (4) adding cationic starch at the inlet of the pulp pump of the pulping pool, the amount of cationic starch used is 12 kg / ton of paper;

[0062] (5) Add amphoteric PAM dry strength agent at the inlet of the pulp pump before papermaking. The amount of amphoteric PAM dry strength agent is 15kg / ton of paper;

[0063] (6) Add AKD and CPAM retention aids after the slurry pump and before the pressure screen. The amount of AKD is 15 kg / ton of paper, and the amount of CPAM retention aid is 200 g / ton of paper;

[0064] (7) Add polyether defoamer into the white water tank outside the machine, the dosage of polyether defoamer is 150g / ton of paper;

[0065] (8) Adding organic bromine fungicide into the pre-papering tank and the white water tank outside the machine, the dosage of organic bromine fungicide is 100g / ton of paper;

[0066] (9) applying a surface sizing agent by an immersion sizing machine, wherein the raw materials for preparing the surface sizing agent include: oxidized corn starch, aluminum sulfate, styrene-acrylate emulsion, and direct red 4BS dye; wherein the amount of oxidized corn starch is 30 kg / ton of paper, the amount of aluminum sulfate is 5 kg / ton of paper, the amount of styrene-acrylate emulsion is 3 kg / ton of paper, and the amount of direct red 4BS dye is 2.0 kg / ton of paper;

[0067] The preparation method of the surface sizing agent is as follows: add an appropriate amount of clean water into a starch cooking tank, start the stirrer, add oxidized corn starch and aluminum sulfate, open the steam valve, heat to 95°C, keep warm for 15 minutes, then move to a starch dilution tank, add styrene-acrylate emulsion, add 55°C warm water, dilute to 4.5% solid content, pH value 5.5, temperature 65°C; add direct red 4BS into the starch dilution tank, stir evenly and move to a starch storage tank for standby use; when the surface sizing agent is used, move from the starch storage tank to the paper machine feeding tank, and pump to the immersion sizing machine for paper dyeing.

[0068] (10) Paper machine operating parameters:

[0069] Adopt 1880mm fourdrinier multi-cylinder paper machine;

[0070] Basis weight: 28g / m 2 ;

[0071] Speed: 260m / min;

[0072] Internet concentration: 0.4%;

[0073] Lip opening: 8mm;

[0074] Shaking: amplitude 15mm, vibration frequency 200 times / min;

[0075] Dryness of the exit roller: 18%;

[0076] Pressing pressure: 60kN / m for first press and 100kN / m for second press;

[0077] Immersion sizing machine pressure: 110kN / m;

[0078] Paper sheet dryness entering sizing machine: 93%%;

[0079] Paper sheet dryness out of sizing machine: 63%;

[0080] Paper dryness: 94%.

[0081] Example 2

[0082] The surface dyeing method of the colored typing paper comprises the following process flow: pulp board → chain conveyor → pulper → unloading tank → pulper → pulping tank → pre-slurry tank → pulping pump → pressure screen → head box → wire part → pressing part → front drying → sizing machine → back drying → winding part → rewinding → packaging and storage;

[0083] in,

[0084] (1) Pulp ratio: 30% bleached kraft softwood pulp, 70% bleached kraft broadleaf pulp;

[0085] (2) Adding light calcium carbonate into the unloading pool, the amount of light calcium carbonate is 180kg / ton of paper;

[0086] (3) Refining: Three DD720 disc refiners are used in series for refining. The first disc refiner uses a cutting-off disc with a refining power of 420 kW. The second and third disc refiners use a debonding disc with a refining power of 350 kW each. The valve opening is 60% and the sizing flow rate is 160 m 3 / h; pulp quality: beating degree: 40°SR, wet weight 3.5g;

[0087] (4) adding cationic starch at the inlet of the pulp pump of the pulping pool, the amount of cationic starch used is 15 kg / ton of paper;

[0088] (5) Add amphoteric PAM dry strength agent at the inlet of the pulp pump before papermaking. The amount of amphoteric PAM dry strength agent is 20kg / ton of paper;

[0089] (6) Add AKD and CPAM retention aids after the pulp pump and before the pressure screen. The amount of AKD is 20 kg / ton of paper, and the amount of CPAM retention aid is 300 g / ton of paper;

[0090] (7) Add polyether defoamer into the white water tank outside the machine, the dosage of polyether defoamer is 200g / ton of paper;

[0091] (8) Adding organic bromine fungicide into the pre-papering tank and the white water tank outside the machine, the dosage of organic bromine fungicide is 150g / ton of paper;

[0092] (9) applying a surface sizing agent by an immersion sizing machine, wherein the raw materials for preparing the surface sizing agent include: oxidized corn starch, aluminum sulfate, styrene-acrylate emulsion, and direct red 4BS dye; wherein the amount of oxidized corn starch is 35 kg / ton of paper, the amount of aluminum sulfate is 10 kg / ton of paper, the amount of styrene-acrylate emulsion is 5 kg / ton of paper, and the amount of direct red 4BS dye is 3.2 kg / ton of paper;

[0093] The preparation method of the surface sizing agent is as follows: add an appropriate amount of clean water into a starch cooking tank, start a stirrer, add oxidized corn starch and aluminum sulfate, open a steam valve, heat to 98°C, keep warm for 20 minutes, then move to a starch dilution tank, add styrene-acrylate emulsion, add 60°C warm water, dilute to 5% solid content, pH value 6.5, temperature 70°C; add direct red 4BS into the starch dilution tank, stir evenly and move to a starch storage tank; when the surface sizing agent is used, move from the starch storage tank to the paper machine feeding tank, and pump to the immersion sizing machine for paper dyeing;

[0094] (10) Paper machine operating parameters:

[0095] Adopt 1880mm fourdrinier multi-cylinder paper machine;

[0096] Basis weight: 28g / m 2 ;

[0097] Speed: 280m / min;

[0098] Internet concentration: 0.5%;

[0099] Lip opening: 10mm;

[0100] Shaking: amplitude 20mm, vibration frequency 220 times / min;

[0101] Dryness of the exit roller: 20%;

[0102] Pressing pressure: 80kN / m for first press and 120kN / m for second press;

[0103] Immersion sizing machine pressure: 130kN / m;

[0104] Paper sheet dryness entering sizing machine: 96%;

[0105] Paper sheet dryness out of sizing machine: 65%;

[0106] Paper dryness: 96%.

[0107] Example 3

[0108] The surface dyeing method of the colored typing paper comprises the following process flow: pulp board → chain conveyor → pulper → unloading tank → pulper → pulping tank → pre-slurry tank → pulping pump → pressure screen → head box → wire part → pressing part → front drying → sizing machine → back drying → winding part → rewinding → packaging and storage;

[0109] in,

[0110] (1) Pulp ratio: 25% bleached kraft softwood pulp, 75% bleached kraft hardwood pulp;

[0111] (2) Adding light calcium carbonate into the unloading pool, the amount of light calcium carbonate is 165kg / ton of paper;

[0112] (3) Refining: Three DD720 disc refiners are used in series for refining. The first disc refiner uses a cutting-off type refiner with a refining power of 420 kW; the second and third disc refiners use a debonding type refiner with a refining power of 350 kW each; the valve opening is 58% and the sizing flow rate is 150 m 3 / h; pulp quality: beating degree: 39°SR, wet weight 3.0g;

[0113] (4) adding cationic starch at the inlet of the pulp pump of the pulping pool, the amount of cationic starch used is 13 kg / ton of paper;

[0114] (5) Add amphoteric PAM dry strength agent at the inlet of the pulp pump before papermaking. The amount of amphoteric PAM dry strength agent is 18 kg / ton of paper;

[0115] (6) Add AKD and CPAM retention aids after the slurry pump and before the pressure screen. The amount of AKD is 17 kg / ton of paper, and the amount of CPAM retention aid is 250 g / ton of paper.

[0116] (7) Add polyether defoamer into the white water tank outside the machine, the dosage of polyether defoamer is 180g / ton of paper;

[0117] (8) Adding organic bromine fungicide into the pre-papering tank and the white water tank outside the machine, the dosage of organic bromine fungicide is 120g / ton of paper;

[0118] (9) applying a surface sizing agent by an immersion sizing machine, wherein the raw materials for preparing the surface sizing agent include: oxidized corn starch, aluminum sulfate, styrene-acrylate emulsion, and direct red 4BS dye; wherein the amount of oxidized corn starch is 32 kg / ton of paper, the amount of aluminum sulfate is 8 kg / ton of paper, the amount of styrene-acrylate emulsion is 4 kg / ton of paper, and the amount of direct red 4BS dye is 2.8 kg / ton of paper;

[0119] The preparation method of the surface sizing agent is as follows: add an appropriate amount of clean water into a starch cooking tank, start a stirrer, add oxidized corn starch and aluminum sulfate, open a steam valve, heat to 97°C, keep warm for 18 minutes, then move to a starch dilution tank, add styrene-acrylate emulsion, add 58°C warm water, dilute to 4.8% solid content, pH value 6.0, temperature 68°C; add direct red 4BS into the starch dilution tank, stir evenly and move to a starch storage tank for standby use; when the surface sizing agent is used, move from the starch storage tank to the paper machine feeding tank, and pump to the immersion sizing machine for paper dyeing;

[0120] (10) Paper machine operating parameters:

[0121] Adopt 1880mm fourdrinier multi-cylinder paper machine;

[0122] Basis weight: 28g / m 2 ;

[0123] Speed: 270m / min;

[0124] Internet concentration: 0.45%;

[0125] Lip opening: 9mm;

[0126] Shaking: amplitude 18mm, vibration frequency 210 times / min;

[0127] Dryness of the exit roller: 19%;

[0128] Pressing pressure: 70kN / m for first press and 110kN / m for second press;

[0129] Immersion sizing machine pressure: 120kN / m;

[0130] Paper sheet dryness entering sizing machine: 95%;

[0131] Paper sheet dryness out of sizing machine: 64%;

[0132] Paper dryness: 95%.

[0133] Example 4

[0134] The only difference between Example 4 and Example 1 is that the direct red 4BS dye is replaced with a whitening agent of equal quality.

[0135] Example 5

[0136] The only difference between Example 5 and Example 2 is that the direct red 4BS dye is replaced with a whitening agent of equal quality.

[0137] Example 6

[0138] The only difference between Example 6 and Example 3 is that the direct red 4BS dye is replaced with a whitening agent of equal quality.

[0139] Comparative Example 1

[0140] 2.8 kg / ton of paper direct scarlet 4BS dye was added in the discharge tank (in the pulp) instead of surface sizing, and other process conditions were consistent with Example 3.

[0141] Comparative Example 2

[0142] The only difference between Comparative Example 2 and Comparative Example 1 is that the direct red 4BS dye is replaced with a brightener of equal quality.

[0143] The color typing paper (red) obtained in Examples 1-3 and Comparative Example 1 was tested for color density using a Konica-Minolta spectrodensitometer FD-5, and the obtained M values ​​are shown in Table 1. The color typing paper (white) obtained in Examples 4-6 and Comparative Example 2 was tested for whiteness according to GB7974-1987, and the obtained data are shown in Table 2.

[0144] The system brushing time of Examples 1-6 and Comparative Examples 1-2 is shown in Tables 1 and 2; wherein the system brushing time is the time taken for the fourdrinier multi-cylinder paper machine to be started up and shut down.

[0145] Table 1 Data table of Examples 1-3 and Comparative Example 1

[0146]

[0147] Table 2 Data table of Examples 4-6 and Comparative Example 2

[0148]

[0149] From the data in Table 1 and Table 2, it can be seen that by using the method of the present invention, adding a brightener or dye to the surface sizing, under the condition of the same dosage, the whiteness and M value representing the color depth of the obtained typing paper are obviously larger, that is, the color is darker or more colorful, and the system brushing time is short. After the production is completed and before the paper machine is shut down, only the surface glue adding equipment needs to be cleaned. When the dye is added to the pulp, after the production is completed and before the paper machine is shut down, all the equipment through which the pulp containing the dye passes needs to be cleaned. The system brushing time is longer, resulting in greater waste of time and labor, and the color of the obtained typing paper is lighter.

Claims

1. A method for dyeing the surface of colored typing paper, characterized in that: The process includes the following: pulp board → chain conveyor → pulper → unloading tank → pulper → pulping tank → pre-pulping tank → pulping pump → pressure screen → headbox → wire section → pressing section → front drying → sizing machine → back drying → winding section → rewinding → packaging and storage; in, (1) Pulp ratio: 20-30% bleached kraft softwood pulp, 80-70% bleached kraft hardwood pulp; (2) Adding light calcium carbonate into the unloading tank; (3) Refining: Three DD720 disc refiners are used in series for refining. The first disc refiner uses a cutting-off disc with a refining power of 420 kW; the second and third disc refiners use a debonding disc with a refining power of 350 kW each; the valve opening is 55%-60%, and the sizing flow rate is 140-160 m 3 / h; pulp quality: beating degree: 38-40°SR, wet weight 2.5-3.5g; (4) adding cationic starch at the inlet of the pulp pump of the pulping tank; (5) Add amphoteric PAM dry strength agent at the inlet of the pulp pump before copying; (6) Add AKD and CPAM retention aids after the slurry pump and before the pressure screen; (7) Add polyether defoamer into the white water tank outside the machine; (8) Add organic bromine fungicide to the pre-watering tank and the white water tank outside the machine; (9) applying a surface sizing agent by an immersion sizing machine, wherein the raw materials for preparing the surface sizing agent include: oxidized corn starch, aluminum sulfate, styrene-acrylate emulsion, brightener or colored dye; (10) Paper machine operating parameters: Adopt 1880mm fourdrinier multi-cylinder paper machine; Basis weight: 28g / m 2 ; Speed: 260-280m / min; Internet concentration: 0.4%-0.5%; Lip opening: 8-10mm; Shaking: Amplitude 15-20mm, vibration frequency 200-220 times / min Dryness of the exit roller: 18-20%; Pressing pressure: 60-80 kN / m for the first press and 100-120 kN / m for the second press; Immersion sizing machine pressure: 110-130kN / m; Dryness of paper entering sizing machine: 93%-96%; Paper sheet dryness out of sizing machine: 63%-65%; Paper dryness: 94%-96%.

2. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The preparation method of the surface sizing agent is as follows: add an appropriate amount of clean water into a starch cooking tank, start a stirrer, add oxidized corn starch and aluminum sulfate, open a steam valve, heat to 95-98°C, keep warm for 15-20 minutes, then move to a starch dilution tank, add styrene-acrylate emulsion, add 55-60°C warm water, dilute to 4.5-5% solid content, pH value 5.5-6.5, temperature 65-70°C; add a brightener or a colored dye into the starch dilution tank, stir evenly and move to a starch storage tank for standby use.

3. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of light calcium carbonate is 150-180kg / ton of paper.

4. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of cationic starch is 12-15kg / ton of paper.

5. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of amphoteric PAM dry strength agent is 15-20kg / ton of paper.

6. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of AKD is 15-20kg / ton of paper.

7. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of CPAM retention aid is 200-300g / ton of paper.

8. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of polyether defoamer is 150-200g / ton of paper.

9. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of organic bromine fungicide is 100-150g / ton of paper.

10. The surface dyeing method of colored typing paper according to claim 1, characterized in that: The dosage of oxidized corn starch is 30-35 kg / ton of paper, the dosage of aluminum sulfate is 5-10 kg / ton of paper, the dosage of styrene-acrylate emulsion is 3-5 kg / ton of paper, and the dosage of brightener or colored dye is 2.0-3.2 kg / ton of paper.

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