A type of double-sided drawing paper for markers and its manufacturing process

Abstract

This application relates to the field of drawing paper, specifically disclosing a double-sided marker drawing paper and its manufacturing process. The double-sided marker drawing paper comprises a first base paper layer, a coating layer, and a second base paper layer arranged sequentially. The coating layer is coated with a coating liquid at a concentration of 1-5 g / m². 2 The coating is applied using a chitosan-sodium alginate-sodium alginate propylene glycol coating solution. This double-sided marker drawing paper, through its composite structure consisting of a first base paper layer, a coating layer composed of chitosan-sodium alginate-sodium alginate propylene glycol, and a second base paper layer, significantly improves the paper's impermeability, preventing ink from seeping to the other side of the paper and ensuring the feasibility of double-sided drawing. It also allows for faster ink penetration and drying, while maintaining the vibrancy and uniform distribution of the marker ink, resulting in a more ideal drawing effect.

Description

Technical Field

[0001] This application relates to the field of drawing paper, and more specifically, to a double-sided drawing paper for markers and its manufacturing process. Background Technology

[0002] In artistic creation and everyday drawing, markers are widely favored for their rich colors, ease of use, and quick drying. However, as people's demands for drawing quality continue to rise, traditional paper presents many challenges when used with markers. Due to the inherent properties of the material, traditional paper is prone to ink penetration, especially when using inks containing alcohol. This phenomenon is particularly pronounced, often resulting in ink penetration that is slow to dry and may even seep to the other side of the paper. This not only affects the drawing effect but also limits the artist's ability to create on the other side of the paper, thus reducing the artistic value and aesthetic appeal of the artwork.

[0003] To address these issues, some papers specifically designed for marker drawing have appeared on the market. For example, Chinese patent CN 112095363A discloses a special paper for marker drawing that prevents ink penetration by coating the paper surface with a waterproof coating. This waterproof coating mainly consists of water-soluble acrylic resin, water-soluble styrene emulsion, wax emulsion, water, and additives, effectively improving the paper's anti-permeability and making the colors more vibrant and uniform. In addition, other methods are widely used, such as increasing the paper's thickness and altering the fiber arrangement, all of which improve the paper's absorbency and anti-permeability to some extent.

[0004] Although existing technologies can alleviate ink penetration problems to some extent, they still have some shortcomings. In particular, for inks containing alcohol, the waterproof coatings in existing technologies often make the ink penetration too slow and the drying time too long, which seriously affects the painter's experience and efficiency. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a double-sided marker drawing paper that allows ink to penetrate quickly, dry quickly, and not penetrate to the other side of the paper, and allows for continued drawing with a marker on the reverse side if needed, as well as its manufacturing process.

[0006] Firstly, this application provides a double-sided drawing paper for markers, which adopts the following technical solution:

[0007] A double-sided marker drawing paper includes a first base paper layer, a coating layer, and a second base paper layer arranged sequentially. The coating layer is made of a coating liquid at a concentration of 1-5 g / m². 2The coating is applied by applying a certain amount of coating solution, which is a chitosan-sodium alginate-sodium alginate propylene glycol coating solution.

[0008] By adopting the above technical solution, the structural design of the first base paper layer, the coating layer, and the second base paper layer not only utilizes the chitosan-sodium alginate-sodium alginate propylene glycol coating solution to give the coating layer excellent impermeability, effectively improving the double-sided drawing performance of the paper, but also solves the problems of slow ink penetration and slow drying speed caused by traditional waterproof coatings. Furthermore, this marker double-sided drawing paper can maintain the vibrancy and uniform distribution of marker ink, resulting in a more ideal drawing effect.

[0009] Preferably, the weight ratio of chitosan, sodium alginate and sodium alginate propylene glycol ester in the chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution is (3-5):1:(1-2).

[0010] The chitosan-sodium alginate-sodium alginate propylene glycol coating solution of this application was prepared by the following method:

[0011] Chitosan was dispersed in glacial acetic acid solution and heated and stirred in a water bath to obtain a chitosan solution. The chitosan solution, sodium alginate aqueous solution, sodium alginate propylene glycol ester aqueous solution and ferulic acid were mixed and magnetically stirred. Glycerin was then added and magnetic stirring was continued. Finally, the mixture was ultrasonically dispersed to obtain a uniform and stable chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution.

[0012] By employing the above-mentioned technical solution, chitosan, sodium alginate, and sodium alginate propylene glycol ester are combined in a certain proportion to form a uniform and dense coating layer on the surface of the second base paper. This uniform and dense coating layer effectively prevents ink from quickly penetrating into the paper and causing the back side to become wet, thus improving the paper's double-sided painting performance. Simultaneously, this coating solution also improves the paper's durability and strength, ensuring that artwork is less prone to fading or deformation during long-term storage. Furthermore, this coating solution makes marker drawings more vibrant and saturated, and easier to layer, enhancing the artistic expression of the artwork. Specifically, chitosan has good film-forming properties and biocompatibility, which can enhance the paper's strength and durability; sodium alginate's thickening properties can adjust the viscosity of the coating solution, making it easier to apply; sodium alginate propylene glycol ester further enhances the coating layer's anti-permeability and fast-drying characteristics, allowing the ink to be fully absorbed and fixed on the paper in a short time. Therefore, the uniform and dense coating layer formed by these three components not only improves the double-sided painting effect of the paper but also significantly enhances the artist's painting experience.

[0013] Preferably, the weight ratio of chitosan, sodium alginate, and sodium alginate propylene glycol ester in the chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution is 4:1:1.5.

[0014] By adopting the above technical solution, this application further optimizes the weight ratio of chitosan, sodium alginate and sodium alginate propylene glycol ester, which can give full play to the synergistic effect among the three, further improve the double-sided painting effect of paper, and enhance the strength and durability of paper.

[0015] Preferably, a nanocellulose layer is further disposed between the coating layer and the second base paper layer.

[0016] Preferably, the nanocellulose layer is formed by coating a nanocellulose suspension with a concentration of 0.5-2wt% with a coating thickness of 0.4-0.6mm.

[0017] The nanocellulose suspension of this application was prepared by the following method:

[0018] Bleached eucalyptus pulp (oven-dry) was dispersed in water to obtain a suspension. Then, while stirring, sodium bromide, 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO), and sodium hypochlorite solution were added sequentially to the suspension to carry out the reaction. During the reaction, the pH of the system was maintained at 9.8-10.0. After the reaction was completed, the reaction product was washed with deionized water by centrifugation, and then homogenized under high pressure and rotary evaporated to obtain a nanocellulose suspension with a concentration of 0.5-2wt%.

[0019] Through the above technical solution, this application utilizes the excellent film-forming properties of nanocellulose to form a thin film on the surface of the second base paper, and then the coating liquid continues to form a dense film on the basis of the nanocellulose film. On the one hand, the nanocellulose film can reduce the penetration of chitosan in the coating liquid into the interior of the second base paper, so that the chitosan can play its role fully. On the other hand, it can give full play to the synergistic effect of the nanocellulose layer and the coating layer, and further enhance the double-sided painting performance and mechanical properties of the paper.

[0020] Secondly, this application provides a manufacturing process for double-sided marker drawing paper, which adopts the following technical solution: A manufacturing process for double-sided marker drawing paper includes the following steps:

[0021] S1. Base paper production: wood pulp fiber raw materials are mixed and pulped to obtain pulp, the pulp is formed on a wire, dewatered on the wire, dewatered by pressing, dried before surface sizing, surface sizing, dried after surface sizing, calendered, and wound to obtain Mark paper base paper.

[0022] S2. Coating process: Divide the base paper into two equal parts to obtain a first base paper and a second base paper. Coat the surface of the second base paper with a chitosan-sodium alginate-sodium alginate propylene glycol coating solution, with a coating amount of 1-5 g / m². 2 After drying, a second base paper with a coating layer is obtained;

[0023] S3. Hot pressing and lamination: The first base paper and the second base paper with a coating layer are laminated, cooled, rewound, and cut to obtain double-sided drawing paper for markers.

[0024] Through the above technical solution, firstly, in the base paper production process, the wood pulp fiber raw materials are mixed and beaten, formed onto a wire, dewatered on the wire section, dewatered by pressing, dried before surface sizing, surface sizing, dried after surface sizing, calendered, and wound, ensuring that the produced double-sided marker drawing paper has high flatness and strength. Secondly, in the coating process, the base paper is divided into two equal parts, serving as the first base paper and the second base paper. The surface of the second base paper is coated with a chitosan-sodium alginate-sodium alginate propylene glycol coating solution. Then, through composite molding, the first base paper and the coated second base paper are tightly bonded together to form a stable structure. This allows the coating layer to improve the paper's impermeability, preventing ink from seeping to the other side of the paper, while also allowing the ink to be fully absorbed and fixed on the paper in a short time. Simultaneously, it maintains good color vibrancy and gradation on the paper, achieving not only a double-sided drawing effect but also rapid ink penetration and drying, significantly improving the drawing experience and efficiency. The entire production process of this application is simple and efficient, suitable for large-scale industrial production.

[0025] Preferably, in the coating process, a nanocellulose suspension with a concentration of 0.5-2wt% is first coated on the surface of the second base paper, with a coating thickness of 0.4-0.6mm. After drying, a chitosan-sodium alginate-sodium alginate propylene glycol coating solution is then applied.

[0026] The above technical solution involves firstly coating the surface of a second base paper with a nanocellulose suspension at a concentration of 0.5-2 wt% to form a nanocellulose layer. This nanocellulose layer effectively improves the paper's strength and tear resistance, while also enhancing the smoothness of the second base paper surface, resulting in a more uniform coating of the subsequent coating solution. Secondly, a chitosan-sodium alginate-sodium alginate propylene glycol coating solution is then applied on top of this layer. This allows the coating layer and the nanocellulose layer to work synergistically, improving the paper's double-sided drawing performance and mechanical properties. Simultaneously, the nanocellulose layer reduces the penetration of chitosan from the coating solution into the second base paper, allowing the chitosan to fully exert its function and further enhancing the paper's double-sided drawing performance and mechanical properties.

[0027] Preferably, the concentration of the adhesive for surface sizing is 4-6 wt%, and the adhesive comprises polyvinyl alcohol and cationic starch, wherein the weight ratio of polyvinyl alcohol to cationic starch is (1-2):1.

[0028] Through the above technical solution, this application uses cationic starch and polyvinyl alcohol as a sizing agent, which enables cationic starch to be adsorbed onto the negatively charged fiber surface through wet-end chemistry, forming a stronger surface-oriented film. Experimental results show that, compared with oxidized starch, cationic starch has better water resistance. Using it in combination with polyvinyl alcohol for sizing not only increases the amount of starch adsorbed on the paper surface but also improves the paper's opacity, whiteness, gloss, and other properties.

[0029] Preferably, the cationic starch comprises cationic amylose and cationic amylopectin in a weight ratio of 1:(3.5-4.5).

[0030] Optionally, the degree of substitution of the cationic starch is 0.04-0.4.

[0031] Preferably, the degree of substitution of the cationic starch is 0.08.

[0032] Through the above technical solution, this application uses a mixture of cationic amylose and cationic amylopectin in the aforementioned ratio. This achieves low substitution degree (0.08), i.e., low cost, while ensuring both are distributed on the surface of paper fibers and between fibers. This results in stronger fiber bonding and increased inter-fiber cohesion, significantly improving the paper's strength and water resistance. Specifically, both the cationic amylose and cationic amylopectin in this application are quaternized amylose and quaternized amylopectin, with a quaternary ammonium group substitution degree ranging from 0.04 to 0.4.

[0033] In summary, this application has the following beneficial technical effects:

[0034] 1. The marker double-sided drawing paper of this application has a composite structure of a first base paper layer, a coating layer composed of chitosan-sodium alginate-sodium alginate propylene glycol ester, and a second base paper layer. This structure significantly improves the paper's anti-permeability, prevents ink from penetrating to the other side of the paper, ensures the feasibility of double-sided drawing, and also makes the ink penetration and drying speed faster. In addition, it maintains the vibrancy and uniform distribution of the marker ink, resulting in a more ideal drawing effect.

[0035] 2. This application adds a nanocellulose layer between the coating layer and the second base paper layer. On the one hand, the nanocellulose film can reduce the penetration of chitosan in the coating liquid into the interior of the second base paper, so that the chitosan can play its role. On the other hand, it can give full play to the synergistic effect of the nanocellulose layer and the coating layer, and further enhance the double-sided painting performance and mechanical properties of the paper.

[0036] 3. This application uses a mixture of cationic amylose and cationic amylopectin, which can significantly improve the strength and water resistance of paper while meeting the requirements of low substitution degree (substitution degree of 0.08) and low cost.

[0037] 4. The entire production process of the marker double-sided drawing paper of this application is simple and efficient, and is suitable for large-scale industrial production. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the marker double-sided drawing paper prepared according to embodiments 1.1-1.5 of this application;

[0039] Figure 2 This is a schematic diagram of the structure of the marker double-sided drawing paper prepared according to embodiments 2.1-2.5 of this application;

[0040] In the diagram, 1 is the first base paper layer; 2 is the second base paper layer; 3 is the coating layer; and 4 is the nanocellulose layer. Detailed Implementation

[0041] The present application will be further described in detail below with reference to the embodiments.

[0042] Unless otherwise specified, all raw materials used in this application are commercially available products.

[0043] Among them, 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO) has the CAS number 2564-83-2, the molecular formula is C9H18NO, the appearance is red crystals, the content is ≥99.0%, and the moisture content is ≤1.0%.

[0044] Both cationic amylose and cationic amylopectin were obtained by activating amylose and amylopectin isolated and purified from corn starch with sodium hydroxide at 65°C, followed by reaction with the cationic etherifying agent 3-chloro-2-hydroxypropyltrimethylammonium chloride to obtain quaternized amylose and quaternized amylopectin with different degrees of substitution (0.04-0.4). The amylose purified from corn starch had a purity of 92.4±1.5% and a weight-average molecular weight of 3.72×10⁻⁶. 4 The purity of amylopectin (DA) is 95.3 ± 1.6%, and the weight-average molecular weight is 2.03 × 10⁻⁶. 4 Da.

[0045] Preparation Example 1.1

[0046] Chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution was prepared by the following method:

[0047] a. Disperse 3 kg of chitosan in glacial acetic acid solution and heat and stir in a water bath at 70°C for 1 hour to obtain a chitosan solution with a mass concentration of 3%; add 1 kg of sodium alginate to deionized water to obtain a sodium alginate aqueous solution with a mass fraction of 1 wt%; add 2 kg of sodium alginate propylene glycol ester to deionized water to obtain a sodium alginate propylene glycol ester aqueous solution with a mass fraction of 2 wt%.

[0048] b. Combine the chitosan solution, sodium alginate aqueous solution and sodium alginate propylene glycol ester aqueous solution, then add 0.1 kg ferulic acid and stir magnetically for 30 min. Then add 0.5 kg glycerol and continue stirring magnetically for 30 min. Finally, ultrasonically disperse for 10 min to obtain a uniform and stable chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution.

[0049] Preparation Example 1.2

[0050] Chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution was prepared by the following method:

[0051] a. Disperse 5 kg of chitosan in glacial acetic acid solution and heat and stir in a water bath at 70°C for 1 hour to obtain a chitosan solution with a mass concentration of 5%; add 1 kg of sodium alginate to deionized water to obtain a sodium alginate aqueous solution with a mass fraction of 1 wt%; add 1 kg of sodium alginate propylene glycol ester to deionized water to obtain a sodium alginate propylene glycol ester aqueous solution with a mass fraction of 1 wt%.

[0052] b. Combine the chitosan solution, sodium alginate aqueous solution and sodium alginate propylene glycol ester aqueous solution, then add 0.1 kg ferulic acid and stir magnetically for 30 min. Then add 0.5 kg glycerol and continue stirring magnetically for 30 min. Finally, ultrasonically disperse for 10 min to obtain a uniform and stable chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution.

[0053] Preparation Example 1.3

[0054] Chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution was prepared by the following method:

[0055] a) Disperse 4 kg of chitosan in glacial acetic acid solution and heat and stir in a 70°C water bath for 1 h to obtain a chitosan solution with a mass concentration of 4%; add 1 kg of sodium alginate to deionized water to obtain a sodium alginate aqueous solution with a mass fraction of 1 wt%; add 1.5 kg of sodium alginate propylene glycol ester to deionized water to obtain a sodium alginate propylene glycol ester aqueous solution with a mass fraction of 1.5 wt%; b) Combine the chitosan solution, sodium alginate aqueous solution and sodium alginate propylene glycol ester aqueous solution, add 0.1 kg of ferulic acid and stir magnetically for 30 min, then add 0.5 kg of glycerol and continue stirring magnetically for 30 min, then ultrasonically disperse for 10 min to obtain a uniform and stable chitosan-sodium alginate-sodium alginate propylene glycol ester coating solution.

[0056] Comparative preparation example 1.1

[0057] The difference from Preparation Example 1.3 is that sodium alginate propylene glycol ester is not added, the amount of sodium alginate used is 2.5 kg, and the rest is the same as Preparation Example 1.3.

[0058] Comparative preparation example 1.2

[0059] The difference from Preparation Example 1.3 is that sodium alginate is not added, and the amount of sodium alginate propylene glycol ester is 2.5 kg. The rest is the same as Preparation Example 1.3.

[0060] Comparative preparation example 1.3

[0061] The difference from Preparation Example 1.3 is that 1 kg of sodium alginate and 1.5 kg of sodium alginate propylene glycol ester are replaced with 2.5 kg of sodium carboxymethyl cellulose, and the rest is the same as Preparation Example 1.3.

[0062] Comparative preparation example 1.4

[0063] The difference from Preparation Example 1.3 is that 4 kg of chitosan was replaced with 4 kg of sodium carboxymethyl cellulose, and the rest is the same as Preparation Example 1.3.

[0064] Preparation Example 2.1

[0065] The nanocellulose suspension was prepared by the following method:

[0066] 4 kg of oven-dried bleached eucalyptus pulp was dispersed in water to obtain a 1 wt% suspension. Then, while stirring, 0.4 kg of sodium bromide and 0.06 kg of 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO) were added to the suspension sequentially, followed by the addition of sodium hypochlorite solution (24 mol of sodium hypochlorite) to the standard volume. The mixture was then stirred to allow the reaction to proceed. During the reaction, the pH of the system was maintained at 9.8-10.0 using 0.5 mol / L NaOH solution. After the reaction was completed, the reaction product was washed with deionized water at 5500 rpm by centrifugation. The product was then homogenized 3-5 times under 15000 PSI high pressure, followed by rotary evaporation to obtain a 0.5 wt% nanocellulose suspension.

[0067] Preparation Example 2.2

[0068] The nanocellulose suspension was prepared by the following method:

[0069] 4 kg of oven-dried bleached eucalyptus pulp was dispersed in water to obtain a 1 wt% suspension. Then, while stirring, 0.4 kg of sodium bromide and 0.06 kg of 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO) were added to the suspension sequentially, followed by the addition of sodium hypochlorite solution (24 mol of sodium hypochlorite) to the standard volume. The mixture was then stirred to allow the reaction to proceed. During the reaction, the pH of the system was maintained at 9.8-10.0 using 0.5 mol / L NaOH solution. After the reaction was completed, the reaction product was washed with deionized water at 5500 rpm by centrifugation. The product was then homogenized 3-5 times under 15000 PSI high pressure, followed by rotary evaporation to obtain a 1.5 wt% nanocellulose suspension.

[0070] Preparation Example 2.3

[0071] The nanocellulose suspension was prepared by the following method:

[0072] 4 kg of oven-dried bleached eucalyptus pulp was dispersed in water to obtain a 1 wt% suspension. Then, while stirring, 0.4 kg of sodium bromide and 0.06 kg of 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO) were added to the suspension sequentially, followed by the addition of sodium hypochlorite solution (24 mol of sodium hypochlorite) to the standard volume. The mixture was then stirred to allow the reaction to proceed. During the reaction, the pH of the system was maintained at 9.8-10.0 using 0.5 mol / L NaOH solution. After the reaction was completed, the reaction product was washed with deionized water at 5500 rpm by centrifugation. The product was then homogenized 3-5 times under 15000 PSI high pressure, followed by rotary evaporation to obtain a 2 wt% nanocellulose suspension.

[0073] Example 1.1

[0074] A manufacturing process for double-sided marker drawing paper includes the following steps:

[0075] S1. Base paper production: Softwood pulp and hardwood pulp are mixed and beaten to obtain pulp (softwood pulp to hardwood pulp weight ratio 3:7), with a freeness of 40°SR. The pulp is then formed onto a wire, dewatered on the wire section, dewatered by pressing, dried before sizing, sizing is applied, dried after sizing, calendered, and wound to obtain 55 g / m² paper. 2 The base paper for Mark paper; the surface sizing uses a 4wt% sizing solution, and the sizing amount is 1.8% of the pulp weight. The weight ratio of polyvinyl alcohol and oxidized starch in the sizing solution is 1:1.

[0076] S2. Coating process: The base paper is divided into two equal parts to obtain a first base paper and a second base paper. The chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in Example 1.1 is coated on the surface of the second base paper, with a coating amount of 1 g / m². 2 After drying, a second base paper with a coating layer is obtained;

[0077] S3. Hot-press lamination: The first base paper and the second base paper with a coating layer are laminated, cooled, rewound, and slit to obtain 120g / m² paper. 2 Marker paper for double-sided drawing.

[0078] Example 1.2

[0079] A manufacturing process for double-sided marker drawing paper includes the following steps:

[0080] S1. Base paper production: Softwood pulp and hardwood pulp are mixed and beaten to obtain pulp (softwood pulp to hardwood pulp weight ratio 3:7), with a freeness of 40°SR. The pulp is then formed onto a wire, dewatered on the wire section, dewatered by pressing, dried before sizing, sizing is applied, dried after sizing, calendered, and wound to obtain 55 g / m² paper. 2 Mark paper base paper; the surface sizing uses a 6wt% sizing solution, with a sizing amount of 1.8% of the pulp weight, and the weight ratio of polyvinyl alcohol and oxidized starch in the sizing solution is 2:1; S2, coating process, the base paper is divided into two equal parts to obtain a first base paper and a second base paper, and the chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in Example 1.2 is coated on the surface of the second base paper, with a coating amount of 5g / m 2 After drying, a second base paper with a coating layer is obtained;

[0081] S3. Hot-press lamination: The first base paper and the second base paper with a coating layer are laminated, cooled, rewound, and slit to obtain 120g / m² paper. 2 Marker paper for double-sided drawing.

[0082] Example 1.3

[0083] A manufacturing process for double-sided marker drawing paper includes the following steps:

[0084] S1. Base paper production: Softwood pulp and hardwood pulp are mixed and beaten to obtain pulp (softwood pulp to hardwood pulp weight ratio 3:7), with a freeness of 40°SR. The pulp is then formed onto a wire, dewatered on the wire section, dewatered by pressing, dried before sizing, sizing is applied, dried after sizing, calendered, and wound to obtain 55 g / m² paper. 2 Mark paper base paper; the surface sizing uses a 3wt% sizing solution, and the sizing amount is 1.8% of the pulp weight. The weight ratio of polyvinyl alcohol and oxidized starch in the sizing solution is 1.5:1.

[0085] S2. Coating process: The base paper is divided into two equal parts to obtain a first base paper and a second base paper. The chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in Example 1.3 is coated on the surface of the second base paper, with a coating amount of 3 g / m². 2 After drying, a second base paper with a coating layer is obtained;

[0086] S3. Hot-press lamination: The first base paper and the second base paper with a coating layer are laminated, cooled, rewound, and slit to obtain 120g / m² paper. 2 Marker paper for double-sided drawing.

[0087] Example 1.4

[0088] A production process for double-sided drawing paper for markers differs from Example 1.3 in that the chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in Example 1.3 is replaced in step S2 with the chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in Example 1.1, while the rest is the same as in Example 1.3.

[0089] Example 1.5

[0090] A production process for double-sided drawing paper for markers differs from Example 1.3 in that the chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in Example 1.3 is replaced in step S2 with the chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in Example 1.2, while the rest is the same as in Example 1.3.

[0091] Example 2.1

[0092] A production process for double-sided drawing paper for markers differs from that in Example 1.3 in that: in step S2, the nanocellulose suspension prepared in Preparation Example 2.1 is first coated on the surface of the second base paper with a coating thickness of 0.4 mm. After drying, a chitosan-sodium alginate-sodium alginate propylene glycol coating solution is then coated. The rest is the same as in Example 1.3.

[0093] Example 2.2

[0094] A production process for double-sided drawing paper for markers differs from that in Example 1.3 in that: in step S2, the nanocellulose suspension prepared in Preparation Example 2.2 is first coated on the surface of the second base paper with a coating thickness of 0.5 mm, and after drying, a chitosan-sodium alginate-sodium alginate propylene glycol coating solution is then coated. The rest is the same as in Example 1.3.

[0095] Example 2.3

[0096] A production process for double-sided drawing paper for markers differs from that in Example 1.3 in that: in step S2, the nanocellulose suspension prepared in Preparation Example 2.3 is first coated on the surface of the second base paper with a coating thickness of 0.6 mm. After drying, a chitosan-sodium alginate-sodium alginate propylene glycol coating solution is then coated. The rest is the same as in Example 1.3.

[0097] Example 2.4

[0098] A production process for double-sided drawing paper for markers differs from that of Example 2.2 in that the nanocellulose suspension obtained in Preparation Example 2.2 is replaced with the nanocellulose suspension obtained in Preparation Example 2.1, while the rest is the same as in Example 2.2.

[0099] Example 2.5

[0100] A production process for double-sided drawing paper for markers differs from that of Example 2.2 in that the nanocellulose suspension obtained in Preparation Example 2.2 is replaced with the nanocellulose suspension obtained in Preparation Example 2.3, while the rest is the same as in Example 2.2.

[0101] Example 3.1

[0102] A production process for double-sided marker drawing paper differs from Example 1.3 in that the oxidized starch in the adhesive solution in step S1 is replaced with cationic linear starch with a quaternary ammonium degree of substitution of 0.4, while the rest is the same as in Example 1.3.

[0103] Example 3.2

[0104] A production process for double-sided drawing paper for markers differs from that in Example 1.3 in that the oxidized starch in the adhesive solution in step S1 is replaced with cationic amylopectin with a quaternary ammonium degree of substitution of 0.2, while the rest is the same as in Example 1.3.

[0105] Example 3.3

[0106] A production process for double-sided drawing paper for markers differs from Example 1.3 in that the oxidized starch in the adhesive solution in step S1 is replaced with cationic amyl starch and cationic amylopectin in a weight ratio of 1:3.5, both with a quaternary ammonium group substitution degree of 0.08. The rest is the same as in Example 1.3.

[0107] Example 3.4

[0108] A production process for double-sided drawing paper for markers differs from Example 1.3 in that the oxidized starch in the adhesive solution in step S1 is replaced with cationic amylose and cationic amylopectin in a weight ratio of 1:4, both with a quaternary ammonium degree of substitution of 0.08. The rest is the same as in Example 1.3.

[0109] Example 3.5

[0110] A production process for double-sided drawing paper for markers differs from Example 1.3 in that the oxidized starch in the adhesive solution in step S1 is replaced with cationic amyl starch and cationic amylopectin in a weight ratio of 1:4.5, both with a quaternary ammonium group substitution degree of 0.08. The rest is the same as in Example 1.3.

[0111] Comparative Examples 1-4

[0112] The difference from Example 1.3 is that the chitosan-sodium alginate-sodium alginate propylene glycol coating solution prepared in step S2 of Example 1.3 is replaced with the coating solutions prepared in Comparative Examples 1.1-1.4, and the rest is the same as in Example 1.3.

[0113] Performance testing

[0114] The papers prepared in Examples 1.1-3.5 and Comparative Examples 1-4 were tested for relevant technical indicators. The results are shown in Table 1. Surface absorbed weight was determined using the Cobb method in GB / T 1540 "Determination of Absorbency of Paper and Paperboard"; opacity was determined using the diffuse reflection method in GB / T 1543 "Determination of Opacity of Paper and Paperboard"; breaking length (longitudinal and transverse average) was determined using the constant-rate tensile method in GB / T 12914 "Determination of Tensile Strength of Paper and Paperboard"; water contact angle was tested on an FTA200 dynamic contact angle analyzer with a contact time of 0.1 s; in practice, an oil-based marker was used to draw a horizontal line on the paper surface. While drawing the line, it was observed whether ink penetrated the back of the paper. Immediately afterward, the paper was wiped with a finger to observe whether ink marks appeared. If no ink marks appeared, it indicated that the ink penetration speed was fast and the drying time was short.

[0115] Table 1 Performance Test Results

[0116]

[0117]

[0118] Data Analysis:

[0119] As can be seen from Table 1, the surface absorbance of the marker double-sided drawing paper prepared in Examples 1.1-1.5 of this application is 28.2-31.4 g / m². 2 The paper exhibits an opacity of 95.8-96.5%, a breaking length of 3618-3635 km, and a water contact angle of 102-106°. Test results show that the double-sided marker drawing paper prepared in Examples 1.1-1.5 of this application has good surface absorption properties, making it suitable for oil-based marker drawing. It also possesses good opacity, preventing ink from penetrating to the other side of the paper, and exhibits good mechanical and hydrophobic properties. In practical application, drawing a horizontal line on the paper with a marker resulted in no ink penetration to the back side; immediate wiping with a finger also left no ink marks. Furthermore, comparing the data from Examples 1.3-1.5 reveals that Example 1.3 further optimized the ratio of chitosan, sodium alginate, and sodium alginate propylene glycol in the coating solution, which can further enhance the coating solution's effect on paper performance.

[0120] The difference between Examples 2.1-2.5 and Example 1.3 lies in that a layer of nanocellulose is first coated onto the surface of the second base paper, and then a coating layer is coated onto the surface of the nanocellulose layer. As shown in Table 1, the paper obtained in Examples 2.2-2.5 exhibits superior properties compared to that in Example 1.3. The experimental results demonstrate that adding nanocellulose between the coating layer and the second base paper layer can further improve the various properties of the paper. Specifically, comparing the data from Examples 2.2 and 2.4-2.5 reveals that further optimizing the mass concentration of the nanocellulose suspension in Example 2.2 can further enhance the reinforcing effect of the nanocellulose layer on the paper.

[0121] The difference between Examples 3.1-3.5 and Example 1.3 lies in the use of cationic starch instead of oxidized starch. As shown in Table 1, the paper produced in Examples 3.1-3.5 exhibits superior properties compared to Example 1.3, particularly a significantly increased water contact angle. The experimental results demonstrate that, compared to oxidized starch, cationic starch can further enhance the water resistance and other properties of the sizing agent, thereby optimizing the paper's overall performance. Furthermore, comparing the data from Examples 3.1-3.2 with those from Examples 3.3-3.5 reveals that Examples 3.3-3.5, by further employing a mixture of cationic amylose and cationic amylopectin, achieves excellent performance with a low degree of substitution, thus reducing costs.

[0122] The difference between Comparative Examples 1-4 and Example 1.3 is that the coating solution did not use a mixture of chitosan, sodium alginate, and sodium alginate propylene glycol ester. As can be seen from Table 1, the properties of the paper prepared in Comparative Examples 1-4 are inferior to those in Example 1.3. The test results show that the mixture of chitosan, sodium alginate, and sodium alginate propylene glycol ester can give full play to their synergistic effect, so as to form a dense structure in the coating layer, thereby improving the reinforcing effect of the coating layer on the paper.

[0123] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A manufacturing process for double-sided marker drawing paper, characterized in that, Includes the following steps: S1. Base paper production: wood pulp fiber raw materials are mixed and pulped to obtain pulp, the pulp is formed on a wire, dewatered on the wire, dewatered by pressing, dried before surface sizing, surface sizing, dried after surface sizing, calendered, and wound to obtain Mark paper base paper. The concentration of the adhesive solution for surface sizing is 4-6 wt%, and the adhesive solution includes polyvinyl alcohol and cationic starch, wherein the weight ratio of polyvinyl alcohol and cationic starch is (1-2):1; The cationic starch comprises cationic amylose and cationic amylopectin in a weight ratio of 1:(3.5-4.5); The degree of substitution of the cationic starch is 0.08; S2, coating processing, the base paper is equally divided into two parts to obtain the first base paper and the second base paper, the surface of the second base paper is coated with a nanocellulose suspension with a concentration of 0.5-2wt% first, the coating thickness is 0.4-0.6mm, and then the coating liquid of chitosan-sodium alginate-sodium alginate propylene glycol ester is coated after drying, the coating amount is 1-5g / m 2 , and then dried to obtain the second base paper with a coating layer; the weight ratio of chitosan, sodium alginate and sodium alginate propylene glycol ester in the coating liquid of chitosan-sodium alginate-sodium alginate propylene glycol ester is 4:1:1.5; S3. Hot pressing and lamination: The first base paper and the second base paper with a coating layer are laminated, cooled, rewound, and cut to obtain double-sided drawing paper for markers.

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