Low basis weight coated paper suitable for siliconizing and method of making the same

Abstract

The application provides a low-basis-weight coated paper suitable for silicon coating and a preparation method thereof; the preparation method comprises the following steps: papermaking a base paper, wherein the paper pulp of the base paper comprises paper pulp and an additive, the additive comprises cationic polyacrylamide and a colloidal solution of silicon dioxide; performing single-side coating on the base paper and drying; and performing gradient calendering to obtain the low-basis-weight coated paper with a basis weight of 32-55 g / m<2>. Compared with the existing low-basis-weight coated paper, the preparation method of the low-basis-weight coated paper suitable for silicon coating provided in the application has the advantages that the silicon oil permeability of the product is reduced by more than 40%, the smoothness difference between two sides is reduced by more than 30%, and the tensile strength is increased by more than 12%; the product is suitable for a high-speed silicon coating production line with a speed of 150-250 m / min, the paper breakage rate is less than 0.5%, and the production efficiency is increased by 50-80% compared with the existing product; the low-basis-weight design and the high-efficiency process reduce the consumption of raw materials and production cost, and the comprehensive cost is reduced by 10-15% compared with similar products.

Description

Technical Field

[0001] This application relates to the technical field of low basis weight coated paper manufacturing process, specifically to a low basis weight coated paper suitable for silicon coating process and its preparation method. Background Technology

[0002] With the development of lightweight and intelligent packaging, low-grammage coated paper is widely used in release labels, electronic die-cutting, food separation, and other fields due to its low cost and good environmental performance. However, when coating these papers with silicone release agents, a series of technical challenges are often encountered: First, the low-grammage base paper has large fiber pores, making it easy for silicone oil to penetrate to the reverse side, leading to paper adhesion and performance degradation; second, the base paper has insufficient strength, making it prone to breakage during high-speed silicone coating, affecting production efficiency; and third, the paper has poor smoothness on both sides, making it prone to defects such as orange peel texture and pinholes after silicone coating, which cannot meet the needs of high-end precision processing. Summary of the Invention

[0003] The first aspect of this application provides a method for preparing low-basis-weight coated paper suitable for silicon coating processing, the preparation method comprising: Papermaking base paper, wherein the base paper pulp includes pulp and additives, the additives including cationic polyacrylamide and silica gel solution; The base paper is coated on one side and then dried; Gradient calendering was performed to obtain low-basis-weight coated paper with a basis weight of 32-55 g / m².

[0004] In some optional embodiments, the pulp stock comprises 10-30% bleached softwood sulfate pulp, 5-15% alkaline hydroperoxide thermomechanical pulp, and the remainder is bleached hardwood sulfate pulp.

[0005] In some optional embodiments, the amount of cationic polyacrylamide added is 0.05%-0.2% of the pulp mass concentration; the amount of silica gel solution added is 0.5%-2% of the pulp mass concentration.

[0006] In some optional embodiments, in the step of coating and drying the base paper on one side, the coating includes pigments and adhesives; wherein, the portion of pigment particles with a particle size of less than or equal to 2 μm accounts for 65-95%; and the mass ratio of pigment to adhesive is 100:(15-21).

[0007] In some optional embodiments, the adhesive is a carboxylated styrene-butadiene latex with a glass transition temperature of 0 to -5°C and a particle size of 140 to 160 nm.

[0008] In some optional embodiments, the coating further includes dyes, dispersants, coating thickeners, and coating water-resistant agents, wherein the mass percentages are as follows: pigment: dye: dispersant: coating thickener: coating water-resistant agent = 100: (0.003-0.01): (0.05-0.35): (0.05-0.35): (0.5-2.5).

[0009] In some optional embodiments, the solid content of the coating is controlled within the range of 18-25%, and the viscosity of the coating is controlled within the range of 300-600 cps.

[0010] In some optional embodiments, the gradient calendering step includes: first performing soft calendering with a pressure of 90-100 kN / m, a temperature of 90-110°C, and a roller surface linear speed of 340-360 m / min; then performing super satin calendering with a pressure of 120-140 kN / m, a temperature of 110-120°C, a roller surface linear speed of 380-420 m / min, and a smoothness difference between the two sides of 10-13 s.

[0011] In some optional embodiments, the preparation method further includes: post-treatment; the conditions are a temperature of 20-25 degrees Celsius, a humidity of 50-55%, and an equilibration time of 24-48 hours.

[0012] Secondly, embodiments of this application provide a low basis weight coated paper suitable for silicon coating processing, wherein the low basis weight coated paper is prepared using the preparation method described in the above embodiments.

[0013] The method for preparing low-basis-weight coated paper suitable for silicone coating processing provided in this application embodiment reduces the silicone oil penetration rate by more than 40%, reduces the difference in smoothness between the two sides by more than 30%, and increases the tensile strength by more than 12% compared with existing low-basis-weight coated paper. It is suitable for high-speed silicone coating production lines of 150-250m / min, with a paper breakage rate of <0.5% and a production efficiency increase of 50-80% compared with existing products. The low-basis-weight design and efficient process reduce raw material consumption and production costs, and the overall cost is reduced by 10-15% compared with similar products. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic flowchart of an embodiment of the method for preparing low basis weight coated paper applicable to silicone coating processing according to this application; Figure 2This is a schematic diagram of the laminated structure of a low-basis-weight coated paper suitable for silicon coating processing in this embodiment; Figure 3 This is a schematic flowchart of another embodiment of the method for preparing low-basis-weight coated paper applicable to silicon coating processing in this application. Detailed Implementation

[0016] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the application. Similarly, the following embodiments are only some, not all, embodiments of the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0017] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0018] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0019] The present invention aims to solve the problems of silicon infiltration, insufficient strength, and poor smoothness in the existing low basis weight coated paper silicon coating process, and to provide a low basis weight coated paper with balanced performance and simple process suitable for silicon coating and its preparation method.

[0020] Please see Figure 1 , Figure 1 This is a schematic flowchart of an embodiment of a method for preparing low-basis-weight coated paper applicable to silicone coating processing, which includes, but is not limited to, the following steps.

[0021] Step S100: Making the original paper.

[0022] In this step, the base pulp comprises pulp and additives, including cationic polyacrylamide and silica gel solution. Optionally, the base pulp comprises 10-30% softwood bleached sulfate pulp, 5-15% alkaline hydroperoxide thermomechanical pulp, and the remainder hardwood bleached sulfate pulp. The freeness of the softwood bleached sulfate pulp is 360 ml, the freeness of the hardwood bleached sulfate pulp is 380 ml, and the freeness of the alkaline hydroperoxide thermomechanical pulp (APMP) is 260 ml.

[0023] The amount of cationic polyacrylamide added is 0.05%-0.2% of the pulp mass concentration; specifically, it can be 0.05%, 0.08%, 0.10%, 0.15%, 0.17%, 0.20%, etc. The amount of silica gel solution added is 0.5%-2% of the pulp mass concentration; specifically, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.7%, 2%, etc.

[0024] The pulp preparation process is as follows: take pulp and add modified filler. After a 10-second interval, add 0.1% cationic polyacrylamide by mass. After a 10-second interval, add 1% silica gel solution by mass. After stirring for 10 seconds, perform water filtration test and sheet making, and test the strength of the hand-made sheet.

[0025] Step S200: Coat one side of the base paper and dry it.

[0026] In step S200, the coating comprises pigments and an adhesive; wherein the pigment particles with a diameter of 2 μm or less account for 65-95%. The mass ratio of pigment to adhesive is 100:(15-21). The pigment may include calcined kaolin and heavy calcium carbonate. The adhesive is carboxylated styrene-butadiene latex with a glass transition temperature of 0-5℃ and a particle size of 140-160 nm.

[0027] Optionally, the coating may also include dyes, dispersants, coating thickeners, and coating water-resistant agents, wherein the mass percentages are as follows: pigment: dye: dispersant: coating thickener: coating water-resistant agent = 100: (0.003-0.01): (0.05-0.35): (0.05-0.35): (0.5-2.5).

[0028] The pigments, adhesives, dyes, dispersants, paint thickeners, and paint water-resistant agents mentioned above are mixed with water in a certain proportion to prepare an intermediate solution with a solid content of 64-68%. Alkali is added to the intermediate solution to adjust the pH to within the range of 9.0±0.5. The final paint solid content is controlled within the range of 18-25%, and the paint viscosity is controlled within the range of 300-600 cps.

[0029] Please see Figure 2 , Figure 2 This is a schematic diagram of the laminated structure of a low-basis-weight coated paper suitable for silicone coating in this embodiment. In the figure, 100 represents the base paper and 200 represents the coating layer.

[0030] The industry conventionally uses nano-silica to enhance coating strength and gloss; this invention, however, uses it in unconventional ways to form a barrier base coating for low-basis-weight paper. Instead of focusing on strengthening and brightening, it works in conjunction with kaolin and calcium carbonate to construct a dense barrier film layer, sealing fiber pores and reducing silicone oil permeability. This represents an unconventional application of the barrier function of nanofillers.

[0031] Please continue reading. Figure 1 The preparation method in this embodiment also includes step S300, which involves gradient calendering.

[0032] In step S300, specifically, a soft calendering process can be performed first, with a pressure of 90-100 kN / m, a temperature of 90-110℃, and a roller surface linear speed of 340-360 m / min; then a super satin calendering process can be performed, with a pressure of 120-140 kN / m, a temperature of 110-120℃, a roller surface linear speed of 380-420 m / min, and a smoothness difference between the two sides of 10-13 s.

[0033] Conventional calendering aims to improve the smoothness of a single surface. This invention, however, adopts a dual-gradient calendering method, using soft calendering to improve the surface smoothness and super calendering to reduce the difference between the two surfaces. Instead of pursuing the ultimate high smoothness, it precisely controls the difference between the two surfaces of smoothness to ≤13s, ensuring the uniformity of silicon coating.

[0034] The method for preparing low-basis-weight coated paper suitable for silicone coating processing provided in this application embodiment reduces the silicone oil penetration rate by more than 40%, reduces the difference in smoothness between the two sides by more than 30%, and increases the tensile strength by more than 12% compared with existing low-basis-weight coated paper. It is suitable for high-speed silicone coating production lines of 150-250m / min, with a paper breakage rate of <0.5% and a production efficiency increase of 50-80% compared with existing products. The low-basis-weight design and efficient process reduce raw material consumption and production costs, and the overall cost is reduced by 10-15% compared with similar products.

[0035] Please see Figure 3 , Figure 3This is a schematic flowchart of another embodiment of the method for preparing low basis weight coated paper applicable to silicon coating processing, which includes, but is not limited to, the following steps.

[0036] Step S100: Making the original paper.

[0037] In this step, the base pulp comprises pulp and additives, including cationic polyacrylamide and silica gel solution. Optionally, the base pulp comprises 10-30% softwood bleached sulfate pulp, 5-15% alkaline hydroperoxide thermomechanical pulp, and the remainder hardwood bleached sulfate pulp. The freeness of the softwood bleached sulfate pulp is 360 ml, the freeness of the hardwood bleached sulfate pulp is 380 ml, and the freeness of the alkaline hydroperoxide thermomechanical pulp (APMP) is 260 ml.

[0038] The amount of cationic polyacrylamide added is 0.05%-0.2% of the pulp mass concentration; specifically, it can be 0.05%, 0.08%, 0.10%, 0.15%, 0.17%, 0.20%, etc. The amount of silica gel solution added is 0.5%-2% of the pulp mass concentration; specifically, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.7%, 2%, etc.

[0039] The pulp preparation process is as follows: take pulp and add modified filler. After a 10-second interval, add 0.1% cationic polyacrylamide by mass. After a 10-second interval, add 1% silica gel solution by mass. After stirring for 10 seconds, perform water filtration test and sheet making, and test the strength of the hand-made sheet.

[0040] Step S200: Coat one side of the base paper and dry it.

[0041] In step S200, the coating comprises pigments and an adhesive; wherein the pigment particles with a diameter of 2 μm or less account for 65-95%. The mass ratio of pigment to adhesive is 100:(15-21). The pigment may include calcined kaolin and heavy calcium carbonate. The adhesive is carboxylated styrene-butadiene latex with a glass transition temperature of 0-5℃ and a particle size of 140-160 nm.

[0042] Optionally, the coating may also include dyes, dispersants, coating thickeners, and coating water-resistant agents, wherein the mass percentages are as follows: pigment: dye: dispersant: coating thickener: coating water-resistant agent = 100: (0.003-0.01): (0.05-0.35): (0.05-0.35): (0.5-2.5).

[0043] The pigments, adhesives, dyes, dispersants, paint thickeners, and paint water-resistant agents mentioned above are mixed with water in a certain proportion to prepare an intermediate solution with a solid content of 64-68%. Alkali is added to the intermediate solution to adjust the pH to within the range of 9.0±0.5. The final paint solid content is controlled within the range of 18-25%, and the paint viscosity is controlled within the range of 300-600 cps.

[0044] Please continue reading. Figure 2 , Figure 2 This is a schematic diagram of the laminated structure of a low-basis-weight coated paper suitable for silicone coating in this embodiment. In the figure, 100 represents the base paper and 200 represents the coating layer.

[0045] The industry conventionally uses nano-silica to enhance coating strength and gloss; this invention, however, uses it in unconventional ways to form a barrier base coating for low-basis-weight paper. Instead of focusing on strengthening and brightening, it works in conjunction with kaolin and calcium carbonate to construct a dense barrier film layer, sealing fiber pores and reducing silicone oil permeability. This represents an unconventional application of the barrier function of nanofillers.

[0046] Please continue reading. Figure 3 The preparation method in this embodiment also includes step S300, which involves gradient calendering.

[0047] In step S300, specifically, a soft calendering process can be performed first, with a pressure of 90-100 kN / m, a temperature of 90-110℃, and a roller surface linear speed of 340-360 m / min; then a super satin calendering process can be performed, with a pressure of 120-140 kN / m, a temperature of 110-120℃, a roller surface linear speed of 380-420 m / min, and a smoothness difference between the two sides of 10-13 s.

[0048] Conventional calendering aims to improve the smoothness of a single surface. This invention, however, adopts a dual-gradient calendering method, using soft calendering to improve the surface smoothness and super calendering to reduce the difference between the two surfaces. Instead of pursuing the ultimate high smoothness, it precisely controls the difference between the two surfaces of smoothness to ≤13s, ensuring the uniformity of silicon coating.

[0049] Please continue reading. Figure 3 Unlike the previous embodiments, the preparation method in this embodiment further includes: step S400, post-processing.

[0050] The post-treatment conditions are a temperature of 20-25 degrees Celsius, a humidity of 50-55%, and an equilibration time of 24-48 hours.

[0051] Several specific implementation examples will be introduced below.

[0052] Blank group (i.e., control group) (1) Low basis weight base paper making: 80% hardwood pulp and 20% softwood pulp were mixed and beaten to a freeness of 350ml and a wet weight of 6.2g; 0.5% cationic starch, 0.2% wet strength agent and 0.05% retention aid were added, and the paper was formed by a long-wire multi-cylinder paper machine to obtain a base paper with a basis weight of 40g / m², a bulk of 1.58cc / g³, an air permeability of 10s and a moisture content of 4.5%; (2) Barrier base coating: By weight, 40 parts of calcined kaolin, 46 parts of heavy calcium carbonate, 10 parts of modified styrene-acrylic emulsion, 2 parts of alcohol-soluble polyamide resin, and 2 parts of nano silica are mixed to prepare a coating with a solid content of 20%; a film transfer coating method is used to coat 4.5 g / ㎡ on one side of the base paper, and it is dried in one stage (110℃). The moisture content after drying is 6%. (3) Gradient calendering finishing: First, soft calendering is performed with a pressure of 95kN / m, a temperature of 100℃, and a roller surface linear speed of 300m / min; then, super satin calendering is performed with a pressure of 100kN / m, a temperature of 100℃, a roller surface linear speed of 400m / min, and a smoothness difference between the two sides of 12s. (4) Post-treatment: Equilibrate for 24 hours at 20℃ and 50% humidity to obtain the finished coated paper.

[0053] Test results: Quantitative strength 40.20 g / m², silicone oil penetration 3.4%, front smoothness 350, back smoothness 350, tensile strength longitudinal 3.1 kN / m, transverse 1.2 kN / m.

[0054] Example 1 (1) Low basis weight base paper making: 70% hardwood pulp, 25% softwood pulp and 5% APMP are mixed and beaten to a freeness of 350ml and a wet weight of 6.2g; 0.5% cationic starch, 0.2% wet strength agent and 0.08% retention aid are added, and the paper is formed by a long-wire multi-cylinder paper machine to obtain a base paper with a basis weight of 40g / m², a bulk of 1.62cc / g³, an air permeability of 12s and a moisture content of 5%; (2) Barrier base coating: By weight, 48 parts of calcined kaolin, 30 parts of heavy calcium carbonate, 15 parts of modified styrene-acrylic emulsion, 3 parts of alcohol-soluble polyamide resin, and 2 parts of nano-silica are mixed to prepare a coating with a solid content of 22%; 4.5 g / ㎡ is coated on one side of the base paper using a film transfer blade coating method, and then dried in a stepped manner (60℃→80℃→105℃), with a moisture content of 6% after drying; (3) Gradient calendering finishing: First, soft calendering is performed with a pressure of 95kN / m, a temperature of 100℃, and a roller surface linear speed of 350m / min; then, super satin calendering is performed with a pressure of 130kN / m, a temperature of 115℃, a roller surface linear speed of 400m / min, and a smoothness difference between the two sides of 12s. (4) Post-treatment: Equilibrate for 36 hours at 24℃ and 52% humidity to obtain the finished coated paper.

[0055] Test results: Quantitative strength 40.2 g / m², silicone oil penetration 2.5%, front smoothness 500, back smoothness 380, tensile strength longitudinal 3.1 kN / m, transverse 1.3 kN / m.

[0056] Example 2 (1) Low basis weight base paper making: 65% hardwood pulp, 28% softwood pulp and 7% APMP are mixed and beaten to a freeness of 400ml and a wet weight of 5.8g; 0.3% cationic starch, 0.15% wet strength agent and 0.06% retention aid are added, and the paper is formed by a long-wire multi-cylinder paper machine to obtain a base paper with a basis weight of 35g / m², a bulk of 1.70cc / m, an air permeability of 15s and a moisture content of 4.5%; (2) Barrier base coating: By weight, 52 parts of calcined kaolin, 28 parts of heavy calcium carbonate, 13 parts of modified styrene-acrylic emulsion, 4 parts of alcohol-soluble polyamide resin, and 1.5 parts of nano silica are mixed to prepare the coating with a solid content of 20%. The coating is applied to one side of the base paper using a slot extrusion coating method with a density of 3.8 g / m². After step drying (58℃→78℃→100℃), the moisture content after drying is 5.5%. (3) Gradient calendering finishing: First, soft calendering is performed with a pressure of 85kN / m, a temperature of 95℃, and a roller surface linear speed of 320m / min; then, super satin calendering is performed with a pressure of 120kN / m, a temperature of 110℃, a roller surface linear speed of 380m / min, and a smoothness difference of 10s between the two sides. (4) Post-treatment: Equilibrate at 23℃ and 50% humidity for 48 hours to obtain the finished coated paper.

[0057] Test results: Quantitative strength 35.1 g / m², silicone oil penetration 2.2%, front smoothness 460°, back smoothness 360°, tensile strength longitudinal 2.9 kN / m, transverse 1.2 kN / m.

[0058] Example 3 (1) Low basis weight base paper making: 72% hardwood pulp, 22% softwood pulp and 6% APMP are mixed and beaten to a freeness of 360ml and a wet weight of 6.8g; 0.7% cationic starch, 0.25% wet strength agent and 0.09% retention aid are added, and the paper is formed by a long-wire multi-cylinder paper machine to obtain a base paper with a basis weight of 50g / m², a bulk of 1.56cc / g, an air permeability of 9s and a moisture content of 5.5%; (2) Barrier base coating: By weight, 42 parts of calcined kaolin, 33 parts of heavy calcium carbonate, 17 parts of modified styrene-acrylic emulsion, 2.5 parts of alcohol-soluble polyamide resin, and 2.5 parts of nano silica are mixed to prepare a coating with a solid content of 25%. The coating is applied to one side of the base paper using a film transfer blade coating method, and then dried in a stepped manner (62℃→82℃→110℃). The moisture content after drying is 6.5%. (3) Gradient calendering finishing: First, soft calendering is performed with a pressure of 105kN / m, a temperature of 102℃, and a roller surface linear speed of 380m / min; then, super satin calendering is performed with a pressure of 140kN / m, a temperature of 118℃, a roller surface linear speed of 430m / min, and a smoothness difference of 13s between the two sides. (4) Post-treatment: Equilibrate for 24 hours at 25℃ and 54% humidity to obtain the finished coated paper.

[0059] Test results: Quantitative strength 50.3 g / m², silicone oil penetration 2.7%, front smoothness 500, back smoothness 380, tensile strength longitudinal 3.3 kN / m, transverse 1.4 kN / m.

[0060] Example 4 (1) Low basis weight papermaking: Same as in Example 1; (2) Barrier base coating: By weight, 48 parts of calcined kaolin, 32 parts of heavy calcium carbonate, 15 parts of modified styrene-acrylic emulsion, 2 parts of alcohol-soluble polyamide resin, 2 parts of nano silica, and 1 part of fluorinated alkyl hydrophobic treatment agent are mixed to prepare a coating with a solid content of 22%; 4.5 g / ㎡ is coated on one side of the base paper using a film transfer blade coating method, and then dried in a stepped manner (60℃→80℃→105℃), with a moisture content of 6% after drying; (3) Gradient calendering finishing: Same as in Example 1; (4) Post-processing: Same as in Example 1.

[0061] Test results: Quantitative strength 40.3 g / m², silicone oil penetration 1.8%, front smoothness 500, back smoothness 500, tensile strength longitudinal 3.2 kN / m, transverse 1.4 kN / m.

[0062] The coating composition ratio and paper properties data are shown in the table below.

[0063]

[0064] The method for preparing low-basis-weight coated paper suitable for silicone coating in this embodiment includes four steps: low-basis-weight base paper making, barrier primer coating, gradient calendering, and post-treatment. Specific process parameters are as described above. This invention provides a low-basis-weight coated paper prepared by the above method, with a basis weight of 32-55 g / m², silicone oil penetration <3%, front-side smoothness ≥45s, back-side smoothness ≥35s, and tensile strength ≥2.8 kN / m longitudinally and ≥1.1 kN / m transversely.

[0065] This preparation method has the following advantages: 1. Performance Synergistic Optimization: Through the synergy of multi-slurry ratio, barrier primer formulation, and gradient calendering process, high barrier properties, high smoothness, and high strength are achieved at low basis weight, solving the performance shortcomings of traditional products, with a finished product qualification rate of >98%; 2. Strong process compatibility: It is compatible with solvent-based and solvent-free silicone coating processes, enabling continuous industrial production and increasing production efficiency by more than 15%. 3. Expanded application scenarios: It can meet the precision processing needs of high-end release labels, electronic die-cutting, food separation and other fields, and its application scope is expanded by 30% compared with traditional products; 4. Significant cost advantage: The low-weight design and efficient process reduce raw material consumption and production costs, resulting in an overall cost reduction of 10-15% compared to similar products.

[0066] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. Any equivalent device or equivalent process transformation made based on the content of this application specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this application.

Claims

1. A method for preparing low basis weight coated paper suitable for silicon coating processing, characterized in that, The preparation method includes: Papermaking base paper, wherein the base paper pulp includes pulp and additives, the additives including cationic polyacrylamide and silica gel solution; The base paper is coated on one side and then dried. Gradient calendering was performed to obtain low-basis-weight coated paper with a basis weight of 32-55 g / m².

2. The preparation method according to claim 1, characterized in that, The base pulp consists of 10-30% bleached softwood sulfate pulp, 5-15% alkaline hydrogen peroxide thermomechanical pulp, and the remainder is bleached hardwood sulfate pulp.

3. The preparation method according to claim 2, characterized in that, The amount of cationic polyacrylamide added is 0.05%-0.2% of the pulp mass concentration; the amount of silica gel solution added is 0.5%-2% of the pulp mass concentration.

4. The preparation method according to claim 1, characterized in that, In the step of coating and drying the base paper on one side, the coating includes pigments and adhesives; wherein, the portion of pigment particles with a diameter of less than or equal to 2μm accounts for 65-95%; and the mass ratio of pigment to adhesive is 100:(15-21).

5. The preparation method according to claim 4, characterized in that, The adhesive is a carboxylated styrene-butadiene latex with a glass transition temperature of 0 to -5℃ and a particle size of 140 to 160 nm.

6. The preparation method according to claim 4, characterized in that, The coating also includes dyes, dispersants, coating thickeners, and coating water-resistant agents, wherein the mass percentages are as follows: pigment: dye: dispersant: coating thickener: coating water-resistant agent = 100: (0.003-0.01): (0.05-0.35): (0.05-0.35): (0.5-2.5).

7. The preparation method according to claim 4, characterized in that, The solid content of the coating is controlled within the range of 18-25%, and the viscosity of the coating is controlled within the range of 300-600 cps.

8. The preparation method according to claim 1, characterized in that, The gradient calendering process includes: first, soft calendering with a pressure of 90-100 kN / m, a temperature of 90-110℃, and a roller surface linear speed of 340-360 m / min; then, super satin calendering with a pressure of 120-140 kN / m, a temperature of 110-120℃, a roller surface linear speed of 380-420 m / min, and a smoothness difference between the two sides of 10-13 s.

9. The preparation method according to claim 1, characterized in that, The preparation method further includes: post-treatment; the conditions are a temperature of 20-25 degrees Celsius, a humidity of 50-55%, and an equilibration time of 24-48 hours.

10. A low-basis-weight coated paper suitable for silicone coating processing, characterized in that, The low basis weight coated paper is prepared by the preparation method according to any one of claims 1-9.

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