Process for preparing a base paper for a cast film with improved cast film fastness

Abstract

The application discloses a preparation process of a calendered paper with improved calendering firmness, and belongs to the papermaking technical field.The technical scheme is as follows: including pulp plate, chain plate conveying, pulper, unloading pool, defibrator, grinding machine, pulp forming pool, pulp forming pool pump, pre-coating pool, pre-coating pool pump, off-machine white water tank, flushing pulp pump, pressure screen, headbox, net part, pressing part, Yankee dryer, film transfer sizing machine, 1800 dryer, calender, winding part, rewinding, packaging and warehousing;100% bleached kraft pulp is used, the beating degree of the pulp forming is controlled to be 30-35SR, the adding amount of chemical reagents, such as talcum powder, sizing agent AKD, cationic corn starch and retention aid, a new surface sizing agent is added, and the moisture of the paper is controlled, so that the synergistic effect between various factors and conditions is achieved, the paper sheet and the PE film are more closely combined, and the problem of poor calendering in the production process of the calendered paper is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of papermaking, and particularly relates to a preparation process of a cast film base paper for improving the cast film fastness. BACKGROUND

[0002] The production process of the food cast film paper is to take food-grade cast film base paper as base paper, form a thin film of hot-melt PE plastic particles on the back of the cast film base paper on a cast film machine, print characters and patterns on the front, and firmly adhere the PE film to the surface of the paper by high temperature and pressure to become a cast film paper. Compared with ordinary paper, the cast film paper has the characteristics of waterproof, moisture-proof, oil-proof and the like, and is widely used in the packaging of various foods, meat products, tea, dried fruits, fruit bags and the like.

[0003] In the existing technology, the cast film paper is mainly produced by using multiple materials or multiple raw material formulations. Chinese utility model patent CN218535895U discloses a cast film paper with good toughness, which comprises a cast film paper body, a wood pulp layer, a waterproof layer, a heat insulation layer, a cast film layer and a rotating drum. The cast film paper body comprises a wood pulp layer, two waterproof layers, two heat insulation layers and two cast film layers. The rotating drum is arranged outside the cast film paper body. The bottom of the rotating drum is provided with a bottom disc. The bottom end of the bottom disc is fixedly connected with an anti-skid pad. The top end of the rotating drum is hingedly connected with a top cover. The two waterproof layers are respectively arranged at the top end and the bottom end of the wood pulp layer. The two heat insulation layers are respectively arranged on one side of the adjacent waterproof layer. The symmetrically arranged cast film layers can prevent oil on both sides, avoiding the disadvantage that the cast film paper can only be used on one side. The symmetrically arranged heat insulation layers further increase the heat insulation effect. The symmetrically arranged waterproof layers can prevent water on both sides. The wood pulp layer with a relatively large thickness can increase the toughness and facilitate use. Chinese invention patent 202110047889.9 discloses a biodegradable low-temperature-resistant cast film paper, which comprises a base paper and a cast film layer. The cast film layer material comprises 70-85wt% polycaprolactone composition, 5-10wt% polylactic acid, 5-10wt% biodegradable thermoplastic polyurethane, 2-5wt% modified additive, 0.1-1wt% antioxidant and 1-10wt% antibacterial agent. The preparation method of the cast film paper comprises the following steps: blending and melting the polycaprolactone and the modified additive, extruding, cooling, granulating and drying; then blending and melting the prepared material with other components, extruding, cooling, granulating and drying to remove moisture to obtain the cast film layer material; and finally drying the base paper after casting the cast film layer material on the base paper by a cast film machine to obtain the cast film paper. The adhesion between the cast film layer material and the base paper is good, and the performance is obviously improved. The prepared cast film paper is not only biodegradable, but also low-temperature-resistant, bend-resistant, antibacterial and gas-barrier, and is especially suitable for cold storage packaging. The cast film paper mainly aims at the biodegradable improvement of the cast film layer, and belongs to the post-processing technology of the cast film base paper.

[0004] In the production process of the coated paper, the PE film and the coated base paper often do not adhere firmly due to the factors of the coated base paper, which is called the poor coating, and the coated paper cannot be processed and used and becomes waste, causing great waste of PE particles and the coated base paper. Therefore, a preparation process of the coated base paper for improving the coating firmness is needed to solve the problem of the poor coating in the production process of the coated paper and reduce the generation of waste. SUMMARY

[0005] The present application provides a preparation process of the coated base paper for improving the coating firmness, which uses 100% bleached kraft pulp, controls the beating degree of the pulp, controls the addition amount of the chemicals, prepares a new surface sizing agent, and controls the moisture of the paper sheet, so that the paper sheet and the PE film are more closely combined, and the problem of the poor coating in the production process of the coated paper is solved.

[0006] The technical scheme of the present application is as follows:

[0007] The preparation process of the coated base paper for improving the coating firmness comprises the following steps: pulp plate, chain plate conveying, pulper, discharge pool, defibrator, refiner, pulp pool, pulp pool pump, pre-draft tank, pre-draft tank pump, machine white water tank, pulping pump, pressure screen, headbox, wire section, press section, Yankee dryer, film transfer sizing machine, 8 pieces of 1800 dryer, calender, winding section, rewinding, packaging and warehousing; specifically, the preparation process comprises the following steps:

[0008] (1) pulp ratio: 100% bleached kraft pulp;

[0009] (2) adding talc at the inlet of the pulper; the talc can compensate the concave-convex points of the paper sheet, ensure the smoothness of the paper sheet, facilitate the leveling of the ink, ensure the bright printing, and reduce the cost if used properly.

[0010] (3) beating process: after the pulp plate is uniformly mixed, one 500 type high-frequency defibrator and two DD720 disc refiners are connected in series for beating, and the disc refiner is a defibration type refiner; the beating degree is 30-35°SR, and the wet weight is 1.5-2.0 g; the beating degree in this range can ensure that the air permeability of the paper sheet is 6-10 um / Pa·s, which is beneficial to the air exhaust during the film coating of the casting machine, prevents the formation of air bubbles between the PE film and the paper sheet, and thus the poor coating is not easily caused; if the beating degree is too low, the fiber bonding strength of the paper sheet is affected, and the paper sheet is easily broken; and if the beating degree is too high, the air permeability of the paper sheet is low, and the poor coating is easily caused during the film coating.

[0011] (4) adding the sizing agent AKD at the pipeline before the pulping pump; the light sizing is ensured, and the appropriate amount is used, which can ensure that the coated paper has appropriate ink absorption, no ink piling and no ink scattering during printing; if the amount is too large, the wax powder is precipitated on the surface of the paper sheet, the bonding force between the PE film and the paper sheet is poor, and the poor coating problem is caused.

[0012] (5) Add cationic corn starch in the pipe before the pulp pump before copying; in order to improve the dry strength of paper, ensure the operation of the paper machine, and also promote the retention of fine fibers and AKD, and ensure the balance of positive and negative in the wet part system.

[0013] (6) Add CPAM retention aid in the pipe before the pressure screen; it is a cationic retention aid, which promotes the retention of anionic fibers and chemicals.

[0014] (7) Add silica sol in the pipe after the pressure screen to form a dual retention with CPAM, and use it after the pressure screen to form a uniform fibrous network structure, which realizes the effect of retention and drainage while ensuring the uniformity.

[0015] (8) Add defoaming agent and bactericide in the off-machine white water tank; the bactericide and defoaming agent have sterilizing effect, prevent the growth of bacteria, and produce sludge, which affects the operation.

[0016] (9) Add surface sizing agent in the sizing machine, the mass concentration of surface sizing agent starch is 10-12%, and the viscosity is 10-20 mPa·s, the surface sizing agent includes the following raw materials: oxidized cassava starch 30-40 kg / ton of paper, polyvinyl alcohol 2-3 kg / ton of paper, and acrylic ester 5-8 kg / ton of paper; the oxidized cassava starch covers the surface of the paper fiber, prevents the falling of fine fibers and fillers, and prevents the problem of powder falling; the polyvinyl alcohol has good film forming property, increases the surface strength of the paper, and has plastic effect after dehydration and drying, thereby improving the stiffness of the paper. The acrylic ester is melted and firmly combined with the PE film at high temperature (film coating temperature 220-230℃) when it is coated in the casting machine, thereby improving the firmness of the film coating.

[0017] (10) Main parameters of the paper machine:

[0018] 1) Speed: 400-500 m / min;

[0019] 2) Lip opening: 12±1 mm;

[0020] 3) Amplitude of shaking: 23±2 mm, shaking frequency: 180±10 times / min;

[0021] 4) Wire concentration: 0.7-0.9%;

[0022] 5) Yankee dryer steam pressure: 500-600 kPa, temperature: 90-100℃;

[0023] 6) Control parameters of film transfer sizing machine:

[0024] Metering rod type and pressure:

[0025] Front metering rod V30, linear pressure: 15 kN / m;

[0026] Reverse metering rod V30, linear pressure 15kN / m;

[0027] Surface sizing agent paper pick-up: front 1.2-1.5g / m 2 , back 1.2-1.5g / m 2 ;

[0028] Film transfer sizing machine paper dryness ≥90%, film transfer sizing machine paper dryness ≥70%;

[0029] 7) Calender: front and back two calender, temperature 150-200℃, linear pressure 120-160KN / m;

[0030] Preferably, the amount of talc added is 150-200kg / ton of paper.

[0031] Preferably, the amount of AKD added is 4-8kg / ton of paper.

[0032] Preferably, the amount of cationic corn starch added is 10-15kg / ton of paper.

[0033] Preferably, the amount of CPAM retention aid added is 100-200g / ton of paper.

[0034] Preferably, the amount of silica sol added is 3-4kg / ton of paper.

[0035] Preferably, the amount of defoaming agent added is 100-200g / ton of paper, and the amount of bactericide added is 80-160g / ton of paper.

[0036] Preferably, the preparation method of the surface sizing agent is: 30-40 parts by weight of oxidized cassava starch, 2-3 parts by weight of polyvinyl alcohol, and 330-374 parts by weight of water are uniformly stirred in a surface sizing cooking pot, then steam is passed, and the temperature is raised to 95±2℃, and the temperature is maintained for 20±2min, then 5-8 parts of acrylate are taken to a surface sizing dilution tank to prepare a surface sizing solution with a mass concentration of 10-12% and a viscosity of 10-20mPa·s, and then taken to a surface sizing storage tank for standby.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] 1. Using 100% bleached kraft pulp, controlling the beating degree of the pulp to be 30-35°SR, controlling the addition amount of chemicals talc, sizing agent AKD, cationic corn starch, retention aid, adding a new type of surface sizing agent, and controlling the moisture content of the paper, the synergistic effect between various factors and conditions makes the paper and PE film more tightly combined, and solves the problem of film coating not firm in the production process of laminated film paper.

[0039] 2. The present application uses 100% bleached kraft pulp, improves paper thickness and surface smoothness, and is beneficial to increase the contact area between PE film and paper, thereby improving the film coating firmness.

[0040] 3. Control the beating degree of the pulp to 30-35°SR, and the air permeability of the paper to 6-10um / Pa.s, which is beneficial to the air exhaust between the PE film and the film coating base paper, reduces the problem of bubble formation and causes the film coating to be not firm, and ensures that the paper has good evenness, which is beneficial to improve the printing quality.

[0041] 4. Control the AKD addition amount to 4-8kg / t paper, which ensures light sizing, can ensure proper ink absorption during printing of the film coating paper, and does not stack ink or disperse ink; and prevents the formation of a wax-like film on the surface of the paper due to excessive AKD dosage, which affects the film coating firmness.

[0042] 5. Use a double-pressure zone soft calender, and press the back of the paper in the second pressure zone, with a temperature of 150-200℃ and a linear pressure of 120-160KN / m, and the back smoothness is ≥50S, which increases the contact area between the back of the film coating base paper and the PE film, thereby improving the film coating firmness.

[0043] 6. Control the moisture content of the paper to 4-5%, which reduces the evaporation amount of moisture during film coating, and improves the film coating firmness; if the moisture content of the paper is too low, the surface of the paper cannot reach the corresponding smoothness and fineness, and the paper is prone to produce wrinkles and other problems during production.

[0044] 7. Surface sizing is added with acrylate, which can soften at high temperature during film coating, so that the paper and the PE film are more closely combined. DETAILED DESCRIPTION

[0045] In order to enable the person skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0046] Embodiment 1

[0047] The present embodiment provides a preparation process of a film coating base paper for improving film coating firmness, which comprises pulp board→chain plate conveying→pulper→discharge pool→500 type defibrator→refiner→pulp pool→pulp pool pump→pre-pulping pool→pre-pulping pool pump→machine white water tank→pulping pump→pressure screen→flow box→wire section→press section→Yankee dryer→film transfer sizing machine→8 pieces of 1800 dryer→calender→winding section→rewinding→packaging and warehousing; specifically:

[0048] (1) Pulp ratio: 100% bleached kraft pulp;

[0049] (2) Adding talc at the inlet of the pulper, the amount of talc added is 150 kg / ton of paper;

[0050] (3) Beating process: after the pulp board is uniformly mixed, a 500 type high frequency defibrator and two DD720 disc mills are used in series for beating, the disc mill blade is a defibration type blade; the degree of beating is 30°SR, the wet weight is 1.5 g;

[0051] (4) Adding sizing agent AKD in the pipeline before the pulp pump, the amount of AKD added is 4 kg / ton of paper;

[0052] (5) Adding cationic corn starch in the pipeline before the pulp pump, the amount of cationic corn starch added is 10 kg / ton of paper;

[0053] (6) Adding CPAM retention aid in the pipeline before the pressure screen, the amount added is 100 g / ton of paper;

[0054] (7) Adding silica sol in the pipeline after the pressure screen, the amount added is 3 kg / ton of paper;

[0055] (8) Adding defoaming agent and bactericide in the white water tank outside the machine, the amount of bactericide added is 80 g / ton of paper, the amount of defoaming agent added is 100 g / ton of paper;

[0056] (9) Adding surface sizing agent in the sizing machine, the mass concentration of surface sizing agent starch is 10%, the viscosity is 10 mPa·s, the surface sizing agent includes the following raw materials: oxidized cassava starch 30 kg / ton of paper, polyvinyl alcohol 2 kg / ton of paper, acrylate 5 kg / ton of paper; the preparation method of the surface sizing agent is: after 30 parts by weight of oxidized cassava starch, 2 parts by weight of polyvinyl alcohol and 330 parts by weight of water are uniformly stirred in the surface sizing cooking tank, steam is passed, and the temperature is raised to 93℃, and the temperature is kept for 18 min, and then it is raised to the surface sizing dilution tank with acrylate 5 parts by weight, to prepare a surface sizing solution with a concentration of 10% and a viscosity of 10 mPa·s, and then it is raised to the surface sizing storage tank for standby.

[0057] (10) Main parameters of the paper machine:

[0058] 1) Speed: 400 m / min;

[0059] 2) Lip opening: 11 mm;

[0060] 3) Amplitude of shaking: 21 mm, shaking frequency: 170 times / min;

[0061] 4) Wire concentration: 0.7%;

[0062] 5) Yankee dryer steam pressure: 500 kPa, temperature: 90℃;

[0063] 6) Film transfer size press control parameters:

[0064] Metering bar model and pressure:

[0065] Front metering bar V30, linear pressure 15 kN / m;

[0066] Back metering bar V30, linear pressure 15 kN / m;

[0067] Surface size pick-up: front 1.2 g / m 2 , back 1.2 g / m 2 ;

[0068] Inlet film transfer size press dryness 91%, outlet film transfer size press dryness 71%;

[0069] 7) Calender: front and back calender, temperature 150℃, linear pressure 120 KN / m.

[0070] Example 2

[0071] The embodiment provides a preparation process of a cast film base paper for improving cast film firmness, and comprises a pulp plate, a chain plate conveying, a pulper, a discharge pool, a 500-type defibrator, a refiner, a pulp forming pool, a pulp forming pool pump, a pre-formation pool, a pre-formation pool pump, an off-machine white water tank, a pulping pump, a pressure screen, a headbox, a wire part, a press part, a Yankee dryer, a film transfer size press, 8 1800 dryers, a calender, a winding part, rewinding and packaging and warehousing, and specifically comprises the following steps:

[0072] (1) Pulp ratio: 100% bleached kraft pulp;

[0073] (2) Adding talc at the inlet of the pulper, and the addition amount of talc is 200 kg / ton of paper;

[0074] (3) Beating process: after the pulp plate is uniformly mixed, a 500-type high-frequency defibrator and two DD720 disc refiners are connected in series for beating, and the disc refiner is a defibration type refiner; degree of kink 35°SR, wet weight 2.0 g;

[0075] (4) Adding sizing agent AKD in the pipeline before the pulping pump, and the addition amount of AKD is 8 kg / ton of paper;

[0076] (5) Adding cationic corn starch in the pre-formation pulp pump, and the addition amount of cationic corn starch is 15 kg / ton of paper;

[0077] (6) Adding CPAM retention aid in the pipeline before the pressure screen, and the addition amount is 200 g / ton of paper;

[0078] (7) Adding silica sol in the pipeline after the pressure screen, and the addition amount is 4 kg / ton of paper;

[0079] (8) Add defoamer and bactericide to the white water tank outside the machine. The amount of bactericide added is 160g / ton of paper, and the amount of defoamer added is 200g / ton of paper.

[0080] (9) Add surface sizing agent to the sizing machine. The surface sizing agent has a starch mass concentration of 12% and a viscosity of 20 mPa·s. The surface sizing agent includes the following raw materials: 40 kg / ton of oxidized cassava starch, 3 kg / ton of polyvinyl alcohol, and 8 kg / ton of acrylate. The preparation method of the surface sizing agent is as follows: 40 parts by weight of oxidized cassava starch, 3 parts by weight of polyvinyl alcohol, and 374 parts by weight of water are added to the surface sizing cooking tank and stirred evenly. Steam is introduced and the temperature is raised to 97°C. The temperature is kept for 22 min. The solution is then transferred to the surface sizing dilution tank and mixed with 8 parts by weight of acrylate to prepare a surface sizing solution with a mass concentration of 12% and a viscosity of 20 mPa·s. The solution is then transferred to the surface sizing storage tank for later use.

[0081] (10) Main parameters of the paper machine:

[0082] 1) Vehicle speed 500m / min;

[0083] 2) Lip opening: 13mm;

[0084] 3) Shaking amplitude: 25mm, shaking frequency: 190 times / min;

[0085] 4) Internet concentration: 0.9%;

[0086] 5) Yankee drying cylinder steam pressure: 600 kPa, temperature: 100℃;

[0087] 6) Control parameters of the film transfer applicator:

[0088] Metering rod type and pressure:

[0089] Front-side metering bar V30, linear pressure 15kN / m;

[0090] Reverse metering bar V30, linear pressure 15kN / m;

[0091] Paper pick-up weight with surface sizing agent: 1.5 g / m² (front side) 2 1.5g / m² on the reverse side 2 ;

[0092] The paper dryness after entering the film transfer sizing machine is 92%, and the paper dryness after exiting the film transfer sizing machine is 73%.

[0093] 7) Calender: double calendering, temperature 150℃, linear pressure 120KN / m.

[0094] Example 3

[0095] The embodiment provides a preparation process of a calendered paper with improved calendered paper firmness, which comprises the following steps: pulp plate, chain plate conveying, pulper, unloading pool, 500 type defibrator, refiner, pulp forming pool, pulp forming pool pump, pre-coating pool, pre-coating pool pump, off-machine white water tank, pulp pump, pressure screen, headbox, wire part, press part, Yankee dryer, film transfer sizing machine, 8 pieces of 1800 dryer, calender, winding part, rewinding, and packaging and warehousing; specifically,

[0096] (1) pulp ratio: 100% bleached kraft pulp;

[0097] (2) talc is added at the inlet of the pulper, and the addition amount of the talc is 180 kg / ton of paper;

[0098] (3) beating process: after the pulp plate is uniformly mixed, one 500 type high-frequency defibrator and two DD720 disc refiners are connected in series for beating, disc mill blades are defibration type mill blades, beating degree is 32°SR, and wet weight is 1.8 g;

[0099] (4) sizing agent AKD is added in the pipeline before the pulp pump, and the addition amount of the AKD is 6 kg / ton of paper;

[0100] (5) cationic corn starch is added in the pre-coating pulp pump, and the addition amount of the cationic corn starch is 13 kg / ton of paper;

[0101] (6) CPAM retention aid is added in the pipeline before the pressure screen, and the addition amount is 150 g / ton of paper;

[0102] (7) silica sol is added in the pipeline after the pressure screen, and the addition amount is 3.5 kg / ton of paper;

[0103] (8) defoaming agent and bactericide are added in the off-machine white water tank, the addition amount of the bactericide is 120 g / ton of paper, and the addition amount of the defoaming agent is 150 g / ton of paper;

[0104] (9) surface sizing agent is added in the sizing machine, the mass concentration of the surface sizing agent starch is 11%, and the viscosity is 15 mPa·s, the surface sizing agent comprises the following raw materials: 35 kg / ton of paper of oxidized cassava starch, 2.5 kg / ton of paper of polyvinyl alcohol, and 7 kg / ton of paper of acrylate; and the preparation method of the surface sizing agent is as follows: 40 parts by weight of oxidized cassava starch, 3 parts by weight of polyvinyl alcohol and 405 parts by weight of water are uniformly stirred in a surface sizing cooking tank, steam is passed, and the temperature is increased to 95 DEG C, and the temperature is kept for 20 min, then 7 parts by weight of acrylate is added to the surface sizing dilution tank to prepare a surface sizing solution with a concentration of 11% and a viscosity of 15 mPa·s, and the surface sizing solution is taken to a surface sizing storage tank for standby.

[0105] (10) main parameters of the paper machine:

[0106] 1) speed of 450 m / min;

[0107] 2) Lip opening: 12 mm;

[0108] 3) Shaking amplitude: 23 mm, shaking frequency: 180 times / min;

[0109] 4) On-machine size: 0.8%;

[0110] 5) Yankee dryer steam pressure: 550 kPa, temperature 95°C;

[0111] 6) Film transfer size press control parameters:

[0112] Metering bar type and pressure:

[0113] Front metering bar V30, linear pressure 15 kN / m;

[0114] Back metering bar V30, linear pressure 15 kN / m;

[0115] Surface size pick-up: front 1.3 g / m 2 , back 1.3 g / m 2 ;

[0116] Inlet film transfer size press paper dryness 93%, outlet film transfer size press paper dryness 71%;

[0117] 7) Calender: front and back calender, temperature 180°C, linear pressure 140 KN / m.

[0118] Comparative Example 1

[0119] Different from Example 3, in this comparative example, the pulp ratio was 80% bleached kraft hardwood pulp and 20% bleached kraft softwood pulp, and other preparation steps and processes were the same as those of Example 3.

[0120] Comparative Example 2

[0121] Different from Example 3, in this comparative example, the beating degree was 40°SR in the beating process, and other preparation steps and processes were the same as those of Example 3.

[0122] Comparative Example 3

[0123] Different from Example 3, in this comparative example, the AKD addition amount was 12 kg / ton of paper, and other preparation steps and processes were the same as those of Example 3.

[0124] Comparative Example 4

[0125] Different from Example 3, in this comparative example, the calender was front and back calender, temperature 80°C, linear pressure 80 KN / m, and other preparation steps and processes were the same as those of Example 3.

[0126] Comparative Example 5

[0127] Different from example 3, in the comparative example 6, the Yankee dryer steam pressure is 300 kPa, the temperature is 65℃, and other preparation steps and processes are the same as example 3.

[0128] Comparative example 6

[0129] Different from example 3, in the comparative example 6, the Yankee dryer steam pressure is 300 kPa, the temperature is 65℃, and other preparation steps and processes are the same as example 3.

[0130] The paper sheets prepared in examples 1-3 and comparative examples 1-6 are tested for performance, and the test standards are shown in table 1, and the test results are shown in table 2.

[0131] Table 1 Papermaking index (50g / m 2 as an example):

[0132]

[0133] Table 2

[0134]

[0135] Comparative example 1 compared with example 3, 20% bleached kraft softwood pulp is used to replace 20% bleached kraft hardwood pulp, and the paper sheet smoothness is reduced; comparative example 2 compared with example 3, the beating degree is increased to above the reasonable range, and the paper sheet air permeability is too low; comparative example 3 compared with example 3, AKD is increased to above the reasonable range, and the paper sheet water absorption is too low; comparative example 4 compared with example 3, the calendering machine pressure and temperature are reduced, thereby reducing the back smoothness, and the back smoothness is low; comparative example 5 compared with example 3, the Yankee dryer steam pressure and temperature are reduced, and the paper sheet moisture is increased, which is higher than the range, and comparative example 6 compared with example 3, the surface sizing agent does not contain acrylate, which affects the combination of paper and PE film. Through the film coating firmness, it can be seen that the PE film is relatively easy to separate from the paper sheet in comparative examples 1-6, while the PE film is difficult to separate from the paper sheet in the film coating base paper produced according to the standard process parameters of the application.

[0136] Although the application has been described in detail through the preferred embodiments, the application is not limited thereto. Those skilled in the art can make various equivalent modifications or replacements to the embodiments of the application without departing from the spirit and essence of the application, and these modifications or replacements shall be within the scope of the application. Therefore, the protection scope of the application shall be subject to the protection scope of the claims.

Claims

1. A process for preparing coated base paper to improve coating adhesion, characterized in that, The process includes: pulp board → chain conveyor → pulper → unloading tank → dewatering machine → refiner → pulping tank → pulping tank pump → pre-powdering tank → pre-powdering tank pump → external white water tank → flushing pump → pressure screen → headbox → wire section → press section → Yankee drying cylinder → film transfer sizing machine → 1800 drying cylinder → calender → winding section → rewinding → packaging and warehousing; specifically: (1) Pulp mix ratio: 100% bleached sulfate hardwood pulp; (2) Add talc powder to the inlet of the pulper; (3) Pulping process: After the pulp boards are mixed evenly, a 500-type high-frequency de-scraping machine and two DD720 disc mills are connected in series for pulping. The disc mills are de-scraping type. The degree of freeness is 30-35°SR and the wet weight is 1.5-2.0g. (4) Add sizing agent AKD to the pipeline before the grouting pump; (5) Add cationic corn starch to the pipeline before the pre-tank pump; (6) Add CPAM retention aid to the pipeline before the pressure screen; (7) Add silica sol to the pipe after the pressure screen; (8) Add defoamer and bactericide to the white water tank outside the machine; (9) Add surface sizing agent to the sizing machine. The surface sizing agent has a starch mass concentration of 10-12% and a viscosity of 10-20 mPa·s. The surface sizing agent includes the following raw materials: 30-40 kg / ton of oxidized cassava starch, 2-3 kg / ton of polyvinyl alcohol, and 5-8 kg / ton of acrylate. (10) Main parameters of the paper machine: 1) Vehicle speed 400-500 m / min; 2) Lip opening: 12±1mm; 3) Shaking amplitude: 23±2mm, shaking frequency: 180±10 times / min; 4) Internet concentration: 0.7-0.9%; 5) Yankee drying cylinder steam pressure: 500-600 kPa, temperature 90-100℃; 6) Control parameters of the film transfer applicator: Metering rod model and pressure Front-side metering bar V30, linear pressure 15kN / m; Reverse metering bar V30, linear pressure 15kN / m; Paper pick-up weight with surface sizing agent: 1.2-1.5 g / m² (front side) 2 The reverse side contains 1.2-1.5 g / m³. 2 ; The paper dryness after entering the film transfer sizing machine is ≥90%, and the paper dryness after exiting the film transfer sizing machine is ≥70%. 7) Calender: double calendering, temperature 150-200℃, linear pressure 120-160KN / m.

2. The preparation process of the coated base paper for improving coating adhesion as described in claim 1, characterized in that, The amount of talc added is 150-200 kg / ton of paper.

3. The preparation process of the coated base paper for improving coating adhesion as described in claim 1, characterized in that, The addition amount of AKD is 4-8 kg / ton of paper.

4. The preparation process of the coated base paper for improving coating adhesion as described in claim 1, characterized in that, The amount of cationic corn starch added is 10-15 kg / ton of paper.

5. The preparation process of the coated base paper for improving coating adhesion as described in claim 1, characterized in that, The amount of CPAM retention aid added is 100-200g / ton of paper.

6. The preparation process of the coated base paper for improving coating adhesion as described in claim 1, characterized in that, The amount of silica sol added is 3-4 kg / ton of paper.

7. The preparation process of the coated base paper for improving coating adhesion as described in claim 1, characterized in that, The amount of defoamer added is 100-200g / ton of paper, and the amount of bactericide added is 80-160g / ton of paper.

8. The preparation process of the coated base paper for improving coating adhesion as described in claim 1, characterized in that, The preparation method of the surface sizing agent is as follows: 30-40 parts by weight of oxidized cassava starch, 2-3 parts by weight of polyvinyl alcohol, and 330-374 parts by weight of water are added to a surface sizing cooking tank and stirred evenly. Steam is introduced and the temperature is raised to 95±2℃ and kept at that temperature for 20±2 min. The mixture is then transferred to a surface sizing dilution tank and mixed with 5-8 parts of acrylate to form a surface sizing agent, thus preparing a surface sizing solution with a concentration of 10-12% and a viscosity of 10-20 mPa·s.

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