Moisture-proof moisture-retaining frame paper and preparation method thereof

Abstract

The invention discloses moisture-proof and moisture-retaining frame paper and a preparation method thereof, and relates to the technical field of frame paper.The moisture-proof and moisture-retaining frame paper comprises a body paper layer, the body paper layer is provided with a water-based moisture-retaining coating, the water-based moisture-retaining coating is formed by drying coated water-based moisture-retaining coating liquid, and the water-based moisture-retaining coating liquid is coated on the body paper layer. A composite aluminum foil layer or a transfer aluminum plating layer is also arranged on the water-based moisture-retaining coating; the water-based moisture-retaining coating liquid comprises starch, acrylic acid, organic bentonite, alkali, an initiator, a cross-linking agent and distilled water; wherein the mass ratio of the starch to the acrylic acid to the organic bentonite is (7-8): (15-20): (1-1.5); the mass of the distilled water is 10-12 times of the total mass of the starch, the acrylic acid and the organic bentonite; the mass of the initiator is 0.5-0.8% of that of the acrylic acid; the mass of the cross-linking agent is 0.1-0.2% of that of the acrylic acid; in terms of-OH, the mole number of the alkali is 70-80% of that of the acrylic acid. The frame paper is provided with the water-based moisture-retaining coating and is excellent in moisture-proof and moisture-retaining performance.

Description

Technical Field

[0001] This invention relates to the field of frame paper technology, specifically to a moisture-proof and moisture-retaining frame paper and its preparation method. Background Technology

[0002] The vast differences in temperature, humidity, and climate across China make the moisture content of tobacco products a crucial indicator for maintaining consistent quality under extreme environmental conditions. Moisture content not only affects the physical properties of tobacco but also its sensory qualities. For example, under dry conditions, tobacco loses moisture quickly, resulting in a noticeably dry feel; under humid conditions, tobacco absorbs moisture from the surrounding air, making it prone to mold.

[0003] Research on moisture retention technology directly affects the moisture content of tobacco products, and this technology is also a key technology for improving the intrinsic quality of tobacco products and enhancing their core competitiveness. Common moisture retention technologies for tobacco products are mainly reflected in tobacco planting, tobacco leaf processing, humectants, packaging materials, and packaging storage. Among these, the selection of tobacco packaging materials has high research value in ensuring the stability of the moisture content within the packaging environment.

[0004] The cigarette pack frame paper is placed at the opening of the cigarette box, serving to support the rigid packaging and cooperate with the lid to close the box. It also acts as a barrier separating the internal environment of the box from the external environment. Existing frame paper does not have moisture-proof and moisture-retaining functions, thus failing to protect the cigarettes during storage. Furthermore, it loses its toughness and stiffness after being exposed to moisture. Therefore, a new type of frame paper with moisture-proof and moisture-retaining functions is needed. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a moisture-proof and moisture-retaining frame paper and its preparation method. Technical solution

[0006] A moisture-proof and moisture-retaining frame paper includes a base paper layer, on which a water-based moisture-retaining coating is applied. The water-based moisture-retaining coating is formed by drying a coated water-based moisture-retaining coating solution. The water-based moisture-retaining coating solution also includes a composite aluminum foil layer or a transfer-metallized layer. The water-based moisture-retaining coating solution comprises: Starch, acrylic acid, organobentonite, alkali, initiator, crosslinking agent, distilled water; The mass ratio of starch, acrylic acid, and organobentonite is 7-8:15-20:1-1.5; the mass of distilled water is 10-12 times the total mass of starch, acrylic acid, and organobentonite; the mass of initiator is 0.5-0.8% of acrylic acid; the mass of crosslinking agent is 0.1-0.2% of acrylic acid; and the molar number of alkali, calculated as -OH, is 70-80% of acrylic acid.

[0007] Furthermore, the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is an ammonium persulfate-sodium bisulfite redox system with a mass ratio of 19:11.

[0008] A method for preparing a moisture-proof and moisture-retaining frame paper includes the following steps: S1: The aqueous wetting coating solution is gravure-coated onto a PET film, and dried to form an aqueous wetting coating layer; the preparation method of the aqueous wetting coating solution is as follows: a: Disperse sodium-based bentonite in distilled water under high-speed stirring, heat to 70°C, add hexadecyltrimethylammonium bromide and stir to react, filter to obtain a white precipitate, wash with water, dry and grind to obtain organo-bentonite; b: Add starch to distilled water and heat to 80°C to gelatinize. Under nitrogen protection, after gelatinization, reduce the temperature to 65°C, add acrylic acid, and add alkali to adjust the degree of neutralization. Then add initiator and well dispersed organic bentonite. After stirring and mixing, add crosslinking agent. After the reaction is complete, the clear liquid obtained is the water-based wetting coating liquid. S2: Use water-based transfer adhesive to transfer the water-based moisturizing coating on the PET film to the base paper layer of the frame paper; S4: A composite aluminum foil layer or a transfer aluminum plating layer is applied to the top of the base paper layer with a water-based moisturizing coating.

[0009] Further, in step a, the mass ratio of sodium bentonite to hexadecyltrimethylammonium bromide is 2:1, and the mass ratio of distilled water to sodium bentonite is 15-20:1; the stirring reaction time is 1-2 hours.

[0010] Furthermore, in step a, the mesh size of the organic bentonite is 200-300 mesh.

[0011] Furthermore, the mixing time in step b is 0.5 h, and the reaction time after adding the crosslinking agent is 3-5 h.

[0012] Furthermore, the base paper layer of the frame paper is white cardboard with a basis weight of 150-230 g / m³. 2 .

[0013] Furthermore, the coating amount of the aqueous moisturizing coating liquid is 15-20 g / m². 2 .

[0014] Beneficial effects:

[0015] This invention provides a moisture-proof and moisture-retaining frame paper and its preparation method. The frame paper has an aqueous moisture-retaining coating, which is obtained by coating with a specially developed aqueous moisture-retaining coating liquid and then drying it. In the preparation of the aqueous moisture-retaining coating liquid, the larger cation of hexadecyltrimethylammonium bromide is used to replace the smaller sodium ions in sodium-based bentonite, resulting in an increase in the interlayer spacing of bentonite. This is beneficial for the subsequent introduction of a polymer with acrylic acid and starch as the framework to form a semi-interpenetrating network structure. Bentonite has excellent hygroscopic properties. Adding bentonite to the polymer resin can improve the water absorption rate of the resin and improve the gel strength after water absorption. This effectively solves the problem of poor toughness and stiffness of the resin after water absorption, avoiding affecting the supporting performance of the frame paper, and thus obtaining a moisture-proof and moisture-retaining frame paper with excellent comprehensive performance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the frame paper structure of the present invention. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings.

[0018] As attached Figure 1 As shown. Example 1:

[0019] A moisture-proof and moisture-retaining frame paper includes a base paper layer 1, on which a water-based moisture-retaining coating layer 2 is formed by drying a coated water-based moisture-retaining coating liquid. The water-based moisture-retaining coating layer 2 also includes a composite aluminum foil layer or a transfer-metallized layer 3. The water-based moisture-retaining coating liquid comprises: Starch, acrylic acid, organobentonite, alkali, initiator, crosslinking agent, distilled water; The mass ratio of starch, acrylic acid, and organobentonite is 7-8:15-20:1-1.5; the mass of distilled water is 10-12 times the total mass of starch, acrylic acid, and organobentonite; the mass of initiator is 0.5-0.8% of acrylic acid; the mass of crosslinking agent is 0.1-0.2% of acrylic acid; and the molar number of alkali, calculated as -OH, is 70-80% of acrylic acid.

[0020] Preferably, the crosslinking agent is N,N'-methylenebisacrylamide; the initiator is an ammonium persulfate-sodium bisulfite redox system with a mass ratio of 19:11. Example 2:

[0021] A method for preparing a moisture-proof and moisture-retaining frame paper includes the following steps: S1: The aqueous wetting coating solution is gravure-coated onto a PET film, and after drying, an aqueous wetting coating is formed; the preparation method of the aqueous wetting coating solution is as follows: a: Disperse 10g of sodium bentonite into 180mL of distilled water under high-speed stirring, heat to 70℃, add 5g of cetyltrimethylammonium bromide and stir for 1.5h, filter to obtain a white precipitate, wash with water, dry, grind and sieve through a 250-mesh sieve to obtain organic bentonite; b: Add 7g of starch to 250mL of distilled water and heat to 80℃ for gelatinization under nitrogen protection. After gelatinization, reduce the temperature to 65℃, add 15g of acrylic acid, and add 6.7g of sodium hydroxide to adjust the neutralization degree. Then add 0.09g of initiator and 1g of well-dispersed organic bentonite. Stir and mix for 0.5h, then add 0.015g of crosslinking agent. After reacting for 3h, the supernatant is obtained, which is the water-based wetting coating liquid. The crosslinking agent is N,N'-methylenebisacrylamide; the initiator is an ammonium persulfate-sodium bisulfite redox system with a mass ratio of 19:11. S2: Use water-based transfer adhesive to transfer the water-based moisturizing coating on the PET film to the base paper layer of the frame paper (white cardboard, 150g / m²). 2 The coating amount is 15g / m². 2 ; S4: A transfer aluminum plating layer is laminated onto the top of the base paper layer using a water-based moisturizing coating. Example 3:

[0022] A method for preparing a moisture-proof and moisture-retaining frame paper includes the following steps: S1: The aqueous wetting coating solution is gravure-coated onto a PET film, and after drying, an aqueous wetting coating is formed; the preparation method of the aqueous wetting coating solution is as follows: a: Disperse 10g of sodium bentonite into 180mL of distilled water under high-speed stirring, heat to 70℃, add 5g of cetyltrimethylammonium bromide and stir for 1.5h, filter to obtain a white precipitate, wash with water, dry, grind and sieve through a 200-mesh sieve to obtain organic bentonite; b: Add 7g of starch to 270mL of distilled water and heat to 80℃ for gelatinization under nitrogen protection. After gelatinization, reduce the temperature to 65℃, add 18g of acrylic acid, and add 7g of sodium hydroxide to adjust the neutralization degree. Then add 0.09g of initiator and 1.2g of well-dispersed organic bentonite. Stir and mix for 0.5h, then add 0.02g of crosslinking agent. After reacting for 5h, the supernatant is obtained, which is the water-based wetting coating liquid. The crosslinking agent is N,N'-methylenebisacrylamide; the initiator is an ammonium persulfate-sodium bisulfite redox system with a mass ratio of 19:11. S2: Use water-based transfer adhesive to transfer the water-based moisturizing coating on the PET film to the base paper layer of the frame paper (white cardboard, 180g / m²). 2 The coating amount is 20g / m². 2 ; S4: A transfer aluminum plating layer is laminated onto the top of the base paper layer using a water-based moisturizing coating. Example 4:

[0023] A method for preparing a moisture-proof and moisture-retaining frame paper includes the following steps: S1: The aqueous wetting coating solution is gravure-coated onto a PET film, and after drying, an aqueous wetting coating is formed; the preparation method of the aqueous wetting coating solution is as follows: a: Disperse 10g of sodium bentonite into 180mL of distilled water under high-speed stirring, heat to 70℃, add 5g of cetyltrimethylammonium bromide and stir for 1.5h, filter to obtain a white precipitate, wash with water, dry, grind and sieve through a 300-mesh sieve to obtain organic bentonite; b: Add 8g of starch to 350mL of distilled water and heat to 80℃ for gelatinization under nitrogen protection. After gelatinization, reduce the temperature to 65℃, add 20g of acrylic acid, and add 8.9g of sodium hydroxide to adjust the neutralization degree. Then add 0.16g of initiator and 1.5g of well-dispersed organic bentonite. Stir and mix for 0.5h, then add 0.03g of crosslinking agent. After reacting for 5h, the supernatant is obtained, which is the water-based wetting coating liquid. The crosslinking agent is N,N'-methylenebisacrylamide; the initiator is an ammonium persulfate-sodium bisulfite redox system with a mass ratio of 19:11. S2: Use water-based transfer adhesive to transfer the water-based moisturizing coating on the PET film to the base paper layer of the frame paper (white cardboard, 230g / m²). 2 The coating amount is 20g / m². 2 ; S4: A transfer aluminum plating layer is laminated onto the top of the base paper layer using a water-based moisturizing coating.

[0024] Experimental example: 1. Water vapor transmission rate test: The water vapor transmission rate of Examples 2-4 and ordinary transfer metallized frame paper (control group) was tested according to GB / T 26253-2010 "Determination of water vapor transmission rate of plastic films and sheets".

[0025]

[0026] Moisturizing performance test: According to GB / T 23203.1—2013, the moisture content of cigarettes in various cigarette packs was measured under natural conditions (temperature 22 ℃, relative humidity 40%) and two extreme humidity changes (temperature 22 ℃, relative humidity 30%) and (temperature 22 ℃, relative humidity 80%). Cigarette packs made with the frame paper of Examples 2-4 were used as the experimental group, and cigarette packs made with ordinary transfer-metallized frame paper were used as the control group. Before the experiment, the cigarette packs were placed at room temperature and humidity (temperature 22 ℃, relative humidity 60%) for 24 hours without being opened. After opening and closing the packs, they were placed in the corresponding test environment, and samples were taken periodically to measure the moisture content of the cigarettes.

[0027] Table 2: Changes in moisture content of cigarettes at a temperature of 22℃ and a relative humidity of 40%

[0028] Table 3: Changes in moisture content of cigarettes at a temperature of 22℃ and a relative humidity of 30%

[0029] Table 4: Changes in moisture content of cigarettes at a temperature of 22℃ and a relative humidity of 60%

[0030] As can be seen from the above test examples, the average water vapor transmission rate of the frame paper prepared in Examples 2-4 is significantly reduced, exhibiting significant moisture absorption properties. Furthermore, the cigarette boxes made from the frame paper of Examples 2-4 have a significant moisture-proof and moisture-retaining effect on cigarettes, which is a significant improvement compared to ordinary transfer-metallized frame paper.

[0031] Although the present invention has been disclosed above with reference to preferred embodiments, these are not intended to limit the invention. Any person skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be defined by the scope of the claims of this application.

Claims

1. A moisture-proof and moisture-retaining frame paper, characterized in that, It includes a base paper layer, on which a water-based moisturizing coating is provided. The water-based moisturizing coating is formed by drying a coated water-based moisturizing coating liquid. A composite aluminum foil layer or a transfer aluminum plating layer is also provided on the water-based moisturizing coating. The aqueous moisturizing coating liquid includes: Starch, acrylic acid, organobentonite, alkali, initiator, crosslinking agent, distilled water; The mass ratio of starch, acrylic acid, and organobentonite is 7-8:15-20:1-1.5; the mass of distilled water is 10-12 times the total mass of starch, acrylic acid, and organobentonite; the mass of initiator is 0.5-0.8% of acrylic acid; the mass of crosslinking agent is 0.1-0.2% of acrylic acid; and the molar number of alkali, calculated as -OH, is 70-80% of acrylic acid.

2. The moisture-proof and moisture-retaining frame paper according to claim 1, characterized in that, The crosslinking agent is N,N'-methylenebisacrylamide; the initiator is an ammonium persulfate-sodium bisulfite redox system with a mass ratio of 19:

11.

3. The method for preparing a moisture-proof and moisture-retaining frame paper according to claim 1, characterized in that, Includes the following steps: S1: The aqueous wetting coating solution is gravure-coated onto a PET film, and dried to form an aqueous wetting coating layer; the preparation method of the aqueous wetting coating solution is as follows: a: Disperse sodium-based bentonite in distilled water under high-speed stirring, heat to 70°C, add hexadecyltrimethylammonium bromide and stir to react, filter to obtain a white precipitate, wash with water, dry and grind to obtain organo-bentonite; b: Add starch to distilled water and heat to 80°C to gelatinize. Under nitrogen protection, after gelatinization, reduce the temperature to 65°C, add acrylic acid, and add alkali to adjust the degree of neutralization. Then add initiator and well dispersed organic bentonite. After stirring and mixing, add crosslinking agent. After the reaction is complete, the clear liquid obtained is the water-based wetting coating liquid. S2: Use water-based transfer adhesive to transfer the water-based moisturizing coating on the PET film to the base paper layer of the frame paper; S4: A composite aluminum foil layer or a transfer aluminum plating layer is applied to the top of the base paper layer with a water-based moisturizing coating.

4. The method for preparing a moisture-proof and moisture-retaining frame paper according to claim 3, characterized in that, In step a, the mass ratio of sodium bentonite to hexadecyltrimethylammonium bromide is 2:1, and the mass ratio of distilled water to sodium bentonite is 15-20:1; the stirring reaction time is 1-2 hours.

5. The method for preparing a moisture-proof and moisture-retaining frame paper according to claim 3, characterized in that, In step a, the organic bentonite has a mesh size of 200-300.

6. The method for preparing a moisture-proof and moisture-retaining frame paper according to claim 3, characterized in that, The mixing time in step b is 0.5 h, and the reaction time after adding the crosslinking agent is 3-5 h.

7. The method for preparing a moisture-proof and moisture-retaining frame paper according to claim 3, characterized in that, The base paper layer of the frame paper is white cardboard with a basis weight of 150-230 g / m³. 2 .

8. The method for preparing a moisture-proof and moisture-retaining frame paper according to claim 3, characterized in that, The coating amount of the aqueous moisturizing coating liquid is 15-20 g / m². 2 .

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