Preparation method of bamboo fiber water-repellent breathable paper

Abstract

The present invention relates to a method for preparing water-repellent and breathable bamboo fiber paper, comprising the following steps: pulping a bleached bamboo pulp board to prepare a pulp with a beating degree of 45-65°SR, adding sodium carboxymethyl cellulose and polyamide polyamine epichlorohydrin resin, and then conveying the pulp to a net, pressing, drying, surface sizing, surface spraying, drying, and winding to obtain the water-repellent and breathable bamboo fiber paper. The surface sizing liquid is obtained by compounding a self-made cationic silicone, an alkyl ketene dimer, and water; and the surface is sprayed with self-made modified polyvinyl alcohol to provide the paper with water resistance. The prepared water-repellent and breathable bamboo fiber paper has a basis weight of 25-40g / m 2 , longitudinal tensile strength ≥3.5kN / m, wet tensile strength ≥0.50kN / m, water absorption ≤9.0g / m 2 , air permeability ≥1.0μm / Pa·s, whiteness ≥80%, softness ≤600mN, moisture 5.0%-7.5%, used for breathable base film for sanitary products, and is biodegradable.

Description

Technical Field

[0001] The invention relates to a method for preparing paper, in particular to a method for preparing bamboo fiber water-repellent and breathable paper. Background Art

[0002] Currently, disposable hygiene products on the market, such as diapers, adult incontinence products, and sanitary napkins, are made from a combination of non-woven fabrics, base films, and absorbent resins. Existing base films typically use PE cast film or PE blown film, which are difficult to degrade naturally and can only be disposed of through landfill or incineration, causing significant pollution to the atmosphere, soil, and water. With the implementation of global plastic bans and the national "carbon peak and carbon neutrality" policy, the development of biodegradable materials is an inevitable trend in future development.

[0003] Sanitary products come into direct contact with human skin, so the performance of the leak-proof bottom film is crucial and should have the following properties: (1) good gas permeability; (2) good water leakage resistance; (3) good tensile strength and tear resistance. If the air permeability of the breathable film is too small, the breathability of the sanitary product will be poor, which may cause adverse effects such as skin allergies or diaper rash. In order to ensure the breathability of sanitary products, the air permeability of the breathable film is generally made relatively large, but this also increases the risk of urine leakage.

[0004] Therefore, it is crucial to develop a new material that is water-repellent, breathable, and biodegradable. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a preparation method for producing water-repellent and breathable paper using bamboo fiber, which can replace traditional PE cast film or PE blown film and be used as a breathable bottom film for sanitary products. It has good water-repellency and air permeability and is biodegradable.

[0006] In order to achieve the above object, the design contents of the present invention are as follows:

[0007] 1. A method for preparing water-repellent, breathable bamboo fiber paper, characterized in that the paper comprises a base paper layer, a sizing layer coated on the surface of the base paper, and a surface super-hydrophobic layer; the base paper layer comprises bamboo fiber, sodium carboxymethyl cellulose, and a polyamide polyamine epichlorohydrin resin; the sizing layer comprises cationic silicone and an alkyl ketene dimer; and the surface super-hydrophobic layer comprises modified polyvinyl alcohol.

[0008] 2. The base paper layer preparation process is as follows: 100% bamboo fiber pulp is selected for beating with a beating degree of 45-65°SR, and auxiliary materials such as sodium carboxymethyl cellulose and polyamide polyamine epichlorohydrin resin are added. After beating, batching, streaming onto a screen, and pressing and drying, the base paper layer is obtained; the amount of sodium carboxymethyl cellulose is 5-15 kg / T paper, and the DS substitution degree is 0.5-0.65; the amount of polyamide polyamine epichlorohydrin resin is 30-50 kg / T paper, and the total content of the organic chlorides 2-chloro-1,3-propylene glycol (DCP) and 3-chloro-1,2-propylene glycol (MCPD) is less than or equal to 100 mg / L.

[0009] 3. The amount of the glue layer is 1.5-2.5g / m 2 The surface sizing solution is prepared by compounding cationic organosilicon, alkyl ketene dimer and water, wherein the ratio of cationic organosilicon to alkyl ketene dimer is 70:30-80:20, the concentration of the sizing solution is 5%-7%, and the operating temperature is 50-65°C; the preparation method of the cationic organosilicon is as follows: in a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, isopropyl alcohol is added, and then single-ended epoxy silicone oil and diethanolamine are added to the three-necked flask in a mass ratio of 1:1-2:1, and nitrogen is passed through the flask for protection, and stirred for 10 The mixture was heated to 80-100°C for 30-15 minutes, and then the temperature was raised to 80-100°C, and 0.001%-0.05% platinum catalyst was added, and the reaction was kept warm for 4-5 hours. Low boiling materials were removed at 90°C and 60kPa vacuum for 30 minutes, and the amino-modified silicone oil was obtained after cooling. Finally, the amino-modified silicone oil and chlorinated toluene were added into a three-necked flask in a mass ratio of 1:1-2:1, and the mixture was reacted in n-hexane solution at 45°C for 30-60 minutes, and then the temperature was raised to 70-90°C and the reaction was carried out for 2-4 hours to obtain cationic silicone.

[0010] 4. The surface super-hydrophobic layer is modified polyvinyl alcohol, and the loading amount is 0.3-0.5g / m 2 ; The modified polyvinyl alcohol is prepared by modifying polyvinyl alcohol with a silane coupling agent; the silane coupling agent is any one of γ-mercaptopropyltriethoxysilane, γ-methacryloxypropylsilane, propyltrimethoxysilane, and hexadecyltriethoxysilane, and the added amount is 50%-80% of the mass of the polyvinyl alcohol.

[0011] 5. The water-repellent and breathable bamboo fiber paper prepared by this preparation method has a basis weight of 25-40g / m 2 , longitudinal tensile strength ≥3.5kN / m, wet tensile strength ≥0.50kN / m, water absorption ≤9.0g / m 2 , air permeability ≥1.0μm / Pa·s, whiteness ≥80%, softness ≤600mN, moisture 5.0%-7.5%.

[0012] The beneficial effects of the present invention include:

[0013] 1. Bamboo, as a natural renewable resource, is biodegradable and environmentally friendly. Made from 100% bamboo fiber, this water-repellent, breathable paper is biodegradable and can replace traditional, difficult-to-degrade backing films for sanitary products. This is safer, more environmentally friendly, and plays a significant role in protecting the ecosystem.

[0014] 2. The prepared cationic silicone and modified polyvinyl alcohol are treated on the surface of the base paper, making the bamboo fiber water-repellent and breathable paper softer than paper produced by traditional production methods. At the same time, it has high water resistance and prevents urine leakage when used as a breathable base film, making it more comfortable to use.

[0015] 3. Compared with traditional breathable bottom film, bamboo fiber water-repellent breathable paper has the capillary effect of bamboo fiber, which can quickly conduct moisture out, making the inside of sanitary products drier and more breathable, effectively reducing the contact between moisture and skin, and further improving the wearing comfort of sanitary products. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] Example 1

[0018] 1. A 100% bamboo fiber pulp sheet was used for beating with a beating degree of 55°SR. 7.0 kg / T of paper, sodium carboxymethyl cellulose with a degree of substitution of 0.60, 37 kg / T of paper, and a polyamide polyamine epichlorohydrin resin with a total organic chloride content of 2-chloro-1,3-propylene glycol (DCP) and 3-chloro-1,2-propylene glycol (MCPD) of 86 mg / L were added. The pulping, batching, conveying to a screen, and pressing and drying were performed to obtain a base paper layer.

[0019] 2. Use the dipping method to apply the surface sizing liquid on the base paper layer in step 1, with a loading amount of 1.5g / m 2The surface sizing solution is prepared by compounding cationic silicone, alkyl ketene dimer and water, the ratio of cationic silicone and alkyl ketene dimer is 75:25, the concentration of the sizing solution is 6.5%, and the operating temperature is 55°C; the preparation method of cationic silicone is as follows: in a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, isopropyl alcohol is added, and then single-ended epoxy silicone oil and diethanolamine are added to the three-necked flask in a mass ratio of 1.5:1, nitrogen is passed through, and stirring is carried out for 15 minutes, then the temperature is raised to 95°C, and 0.03% platinum catalyst is added, and the reaction is kept warm for 4.5 hours, and low boiling points are removed at 90°C and 60kPa vacuum for 30 minutes, and amino-modified silicone oil is obtained after cooling. Finally, amino-modified silicone oil and chlorinated toluene are added to the three-necked flask in a mass ratio of 1.5:1, and the reaction is carried out in a n-hexane solution at 45°C for 50 minutes, and then the temperature is raised to 85°C and the reaction is carried out for 3 hours;

[0020] 3. Spray the modified polyvinyl alcohol onto the paper surface after sizing in step 2, with a spraying amount of 0.3g / m 2 The modified polyvinyl alcohol is prepared by modifying polyvinyl alcohol with γ-mercaptopropyltriethoxysilane, and the addition amount is 70% of the mass of the polyvinyl alcohol;

[0021] 4. The paper sample in step 3 is dried to obtain bamboo fiber water-repellent and breathable paper.

[0022] Example 2

[0023] 1. A 100% bamboo fiber pulp sheet was used for beating with a beating degree of 55°SR. 7.0 kg / T of paper, sodium carboxymethyl cellulose with a degree of substitution of 0.60, 37 kg / T of paper, and a polyamide polyamine epichlorohydrin resin with a total organic chloride content of 2-chloro-1,3-propylene glycol (DCP) and 3-chloro-1,2-propylene glycol (MCPD) of 86 mg / L were added. The pulping, batching, conveying to a screen, and pressing and drying were performed to obtain a base paper layer.

[0024] 2. Use the dipping method to apply the surface sizing liquid on the base paper layer in step 1, with a loading amount of 2.0g / m 2The surface sizing solution is prepared by compounding cationic silicone, alkyl ketene dimer and water, the ratio of cationic silicone and alkyl ketene dimer is 75:25, the concentration of the sizing solution is 6.5%, and the operating temperature is 55°C; the preparation method of cationic silicone is as follows: in a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, isopropyl alcohol is added, and then single-ended epoxy silicone oil and diethanolamine are added to the three-necked flask in a mass ratio of 1.5:1, nitrogen is passed through, and stirring is carried out for 15 minutes, then the temperature is raised to 95°C, and 0.03% platinum catalyst is added, and the reaction is kept warm for 4.5 hours, and low boiling points are removed at 90°C and 60kPa vacuum for 30 minutes, and amino-modified silicone oil is obtained after cooling. Finally, amino-modified silicone oil and chlorinated toluene are added to the three-necked flask in a mass ratio of 1.5:1, and the reaction is carried out in a n-hexane solution at 45°C for 50 minutes, and then the temperature is raised to 85°C and the reaction is carried out for 3 hours;

[0025] 3. Spray the modified polyvinyl alcohol onto the paper surface after sizing in step 2, with a spraying amount of 0.4g / m 2 The modified polyvinyl alcohol is prepared by modifying polyvinyl alcohol with γ-mercaptopropyltriethoxysilane, and the addition amount is 70% of the mass of the polyvinyl alcohol;

[0026] 4. The paper sample in step 3 is dried to obtain bamboo fiber water-repellent and breathable paper.

[0027] Example 3

[0028] 1. A 100% bamboo fiber pulp sheet was used for beating with a beating degree of 55°SR. 7.0 kg / T of paper, sodium carboxymethyl cellulose with a degree of substitution of 0.60, 37 kg / T of paper, and a polyamide polyamine epichlorohydrin resin with a total organic chloride content of 2-chloro-1,3-propylene glycol (DCP) and 3-chloro-1,2-propylene glycol (MCPD) of 86 mg / L were added. The pulping, batching, conveying to a screen, and pressing and drying were performed to obtain a base paper layer.

[0029] 2. Use the dipping method to apply the surface sizing liquid on the base paper layer in step 1, with a loading amount of 2.5g / m 2The surface sizing solution is prepared by compounding cationic silicone, alkyl ketene dimer and water, the ratio of cationic silicone and alkyl ketene dimer is 75:25, the concentration of the sizing solution is 6.5%, and the operating temperature is 55°C; the preparation method of cationic silicone is as follows: in a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, isopropyl alcohol is added, and then single-ended epoxy silicone oil and diethanolamine are added to the three-necked flask in a mass ratio of 1.5:1, nitrogen is passed through, and stirring is carried out for 15 minutes, then the temperature is raised to 95°C, and 0.03% platinum catalyst is added, and the reaction is kept warm for 4.5 hours, and low boiling points are removed at 90°C and 60kPa vacuum for 30 minutes, and amino-modified silicone oil is obtained after cooling. Finally, amino-modified silicone oil and chlorinated toluene are added to the three-necked flask in a mass ratio of 1.5:1, and the reaction is carried out in a n-hexane solution at 45°C for 50 minutes, and then the temperature is raised to 85°C and the reaction is carried out for 3 hours;

[0030] 3. Spray the modified polyvinyl alcohol onto the paper surface after sizing in step 2, with a spraying amount of 0.5g / m 2 The modified polyvinyl alcohol is prepared by modifying polyvinyl alcohol with γ-mercaptopropyltriethoxysilane, and the addition amount is 70% of the mass of the polyvinyl alcohol;

[0031] 4. The paper sample in step 3 is dried to obtain bamboo fiber water-repellent and breathable paper.

[0032] Comparative Example 1

[0033] 1. A 100% bamboo fiber pulp sheet is used for beating with a beating degree of 55°SR, and 7.0 kg / T of paper, sodium carboxymethyl cellulose with a degree of substitution of 0.60, 37 kg / T of paper, and a polyamide polyamine epichlorohydrin resin containing 86 mg / L of the organic chlorides 2-chloro-1,3-propylene glycol (DCP) and 3-chloro-1,2-propylene glycol (MCPD) are added. The pulp is then beaten, batched, conveyed onto a screen, pressed and dried, and rolled to obtain bamboo fiber paper.

[0034] Comparative Example 2

[0035] 1. A 100% bamboo fiber pulp board was used for beating at a beating degree of 45°SR. 7.0 kg / T of paper, sodium carboxymethyl cellulose with a degree of substitution of 0.60, 30 kg / T of paper, and a polyamide polyamine epichlorohydrin resin with a total organic chloride content of 2-chloro-1,3-propylene glycol (DCP) and 3-chloro-1,2-propylene glycol (MCPD) of 86 mg / L were added. After beating, batching, flowing onto a screen, pressing and drying, a base paper layer was obtained.

[0036] 2. Use the dipping method to apply the surface sizing liquid on the base paper layer in step 1, with a loading amount of 2.0g / m 2The surface sizing solution is prepared by compounding cationic silicone, alkyl ketene dimer and water, the ratio of cationic silicone and alkyl ketene dimer is 75:25, the concentration of the sizing solution is 6.5%, and the operating temperature is 55°C; the preparation method of cationic silicone is as follows: in a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, isopropyl alcohol is added, and then single-ended epoxy silicone oil and diethanolamine are added to the three-necked flask in a mass ratio of 1.5:1, nitrogen is passed through, and stirring is carried out for 15 minutes, then the temperature is raised to 95°C, and 0.03% platinum catalyst is added, and the reaction is kept warm for 4.5 hours, and low boiling points are removed at 90°C and 60kPa vacuum for 30 minutes, and amino-modified silicone oil is obtained after cooling. Finally, amino-modified silicone oil and chlorinated toluene are added to the three-necked flask in a mass ratio of 1.5:1, and the reaction is carried out in a n-hexane solution at 45°C for 50 minutes, and then the temperature is raised to 85°C and the reaction is carried out for 3 hours;

[0037] 3. The paper sample in step 2 is dried and rolled up to obtain the bamboo fiber water-repellent and breathable paper that has been sizing-treated.

[0038] The physical indexes of the water-repellent and breathable bamboo fiber papers prepared in the above three embodiments and two comparative examples were tested. The test results are shown in Table 1:

[0039] Table 1 Physical indicators of bamboo fiber water-repellent breathable paper

[0040] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Detection method <![CDATA[Quantitative g / m 2 > 32.1 32.4 32.7 31.3 32.2 GB / T451.2-2002 Dry tensile strength kN / m 3.9 4.1 4.2 3.5 3.6 GB / T12914-2008 Wet tensile strength kN / m 0.55 0.61 0.63 0.42 0.49 GB / T12914-2008 <![CDATA[Water absorption g / m 2 > 7.8 7.1 6.5 35 26 GB / T1540-2002 Air permeability μm / Pa·s 2.4 1.8 1.3 6.1 1.7 GB / T458-2008 Softness mN 563 534 432 856 560 GB / T 8942-2002 Whiteness 83 82 83 83 82 GB / T22880-2008 Moisture% 6.7 6.6 6.8 6.8 6.7 GB / T462-2008

[0041] Comparative Example 2 adds a surface sizing process relative to Comparative Example 1, but does not have a surface super-hydrophobic treatment. The surface sizing loading amount and the super-hydrophobic layer spraying amount in Examples 1, 2, and 3 are gradually increased. From the results of physical test indicators, it can be seen that the water absorption, softness, and wet tensile strength of the paper sample of Comparative Example 2 are better than those of Comparative Example 1, indicating that after the surface sizing liquid impregnation treatment, the softness and wet strength of the paper are improved, and the water resistance is significantly enhanced. Example 2 is sprayed with a homemade modified polyvinyl alcohol on the surface of Comparative Example 2, and the water absorption value is significantly reduced, and the water resistance is significantly enhanced.

[0042] The dry tensile strength, wet tensile strength and water resistance of Example 1, Example 2 and Example 3 gradually increase, the softness decreases, the softness increases, and the air permeability shows a decreasing trend, indicating that after the homemade cationic silicone compound alkyl ketene dimer is coated on the surface of the base paper layer, the softness of the paper is greatly improved. After the surface is sprayed with modified polyvinyl alcohol, the water resistance of the paper is significantly enhanced.

[0043] The water-repellent and breathable bamboo fiber paper prepared by the method of the present invention is soft, highly water-resistant, and has good air permeability. When used as a breathable bottom film for sanitary products, it is comfortable to use, effectively prevents leakage, can quickly conduct moisture, and provides a drier use environment. It is also biodegradable.

[0044] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing bamboo fiber water-repellent breathable paper, characterized by: The water-repellent and breathable bamboo fiber paper is prepared by sequentially applying a sizing layer and a surface super-hydrophobic layer to the surface of a base paper layer, followed by drying. The base paper layer preparation process is as follows: 100% bamboo fiber pulp is selected for beating with a beating degree of 45-65°SR, and auxiliary materials such as sodium carboxymethyl cellulose and polyamide polyamine epichlorohydrin resin are added. After beating, batching, flowing onto a screen, pressing and drying, the base paper layer is obtained. The sizing layer is compounded from cationic silicone, alkyl ketene dimer, and water. The preparation method of the cationic silicone is as follows: isopropyl alcohol is added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then single-ended epoxy silicone oil and diethanolamine are added to the three-necked flask in a mass ratio of 1:1-2:1, nitrogen is passed through, and stirring is performed for 10-15 minutes, and then the temperature is raised to 80-100° C., and then 0.001%-0.05% platinum catalyst is added, and the temperature is kept for reaction for 4-5 hours, and low-boiling substances are removed at 90° C. and 60 kPa vacuum for 30 minutes, and then cooled to obtain amino-modified silicone oil. Finally, the amino-modified silicone oil and chlorinated toluene are added to the three-necked flask in a mass ratio of 1:1-2:1, and the reaction is carried out in an n-hexane solution at 45° C. for 30-60 minutes, and then the temperature is raised to 70-90° C. and the reaction is carried out for 2-4 hours to obtain the cationic silicone. The surface super-hydrophobic layer is prepared from modified polyvinyl alcohol, which is prepared from polyvinyl alcohol modified with a silane coupling agent. The silane coupling agent is any one of γ-mercaptopropyltriethoxysilane, Y-methacryloxypropylsilane, propyltrimethoxysilane, and hexadecyltriethoxysilane, and the added amount is 50%-80% of the mass of the polyvinyl alcohol.

2. The method for preparing a water-repellent and breathable bamboo fiber paper according to claim 1, wherein: The amount of sodium carboxymethyl cellulose in the base paper layer is 5-15 kg / T paper, and the DS substitution degree is 0.5-0.65; the amount of the polyamide polyamine epichlorohydrin resin is 30-50 kg / T paper, and the total content of the organic chlorides 2-chloro-1,3-propylene glycol (DCP) and 3-chloro-1,2-propylene glycol (MCPD) is less than or equal to 100 mg / L.

3. The method for preparing a water-repellent and breathable bamboo fiber paper according to claim 1, wherein: The amount of the glue layer is 1.5-2.5g / m 2 The ratio of cationic silicone and alkyl ketene dimer is 70:30-80:20, the concentration of the sizing solution is 5%-7%, and the operating temperature is 50-65℃.

4. The method for preparing a water-repellent and breathable bamboo fiber paper according to claim 1, wherein: The amount of the surface super hydrophobic layer is 0.3-0.5 g / m 2 .

5. The method for preparing a water-repellent and breathable bamboo fiber paper according to claim 1, wherein: The water-repellent and breathable bamboo fiber paper prepared by the preparation method has a basis weight of 25-40g / m 2 , longitudinal tensile strength ≥3.5kN / m, wet tensile strength ≥0.50kN / m, water absorption ≤9.0g / m 2 , air permeability ≥1.0μm / Pa·s, whiteness ≥80%, softness ≤600mN, moisture 5.0%-7.5%.