Method for preparing waterproof paper with waterproof and oil-proof film

Abstract

The present invention relates to the technical field of waterproof paper, and discloses a method for preparing waterproof paper with a waterproof and oil-proof film. The present invention uses fluorosilicone monomers and monomers such as acrylic acid to polymerize to obtain a fluorosilicone polyacrylate waterproof agent, which is preferably compounded with oxidized starch to obtain a waterproof sizing agent. The paper surface is coated with sizing agent, and the sizing agent forms a unique waterproof coating film containing diphenylhexafluoropropane and methylchlorosilane structure on the paper surface. The water contact angle of the paper reaches 11.22-138.4°, the paraffin oil contact angle reaches 83.6-114.2°, and the water absorption is only 10.1-18.6g / m 2 , showing good waterproof and oil-proof properties. And the tear strength of the paper reaches 72-81mN, with excellent mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof paper, in particular to a method for preparing waterproof paper with a waterproof and oil-proof film attached thereto. Background Art

[0002] Waterproof paper is widely used in packaging materials and other fields. Traditional paper products have poor water and oil resistance and low strength. The use of sizing agents can effectively improve the performance of paper products. It is mainly divided into internal sizing and surface sizing. Among them, surface sizing is to apply sizing on the surface of paper. The polymer molecules in the sizing agent can penetrate into the fiber gaps of the paper and fill the gaps, which can effectively improve the mechanical properties of the paper. The main components of the current sizing agent are starch, polyacrylate, polyvinyl alcohol, etc.; Chinese patent CN115627655B discloses a method for preparing an air-drying oil-modified amphoteric polyacrylate emulsion surface sizing agent, using bio-based monomer b, butyl acrylate, air-drying oil-modified amphoteric polyacrylate polymer emulsifier, etc. as raw materials, preparing an emulsion by emulsion polymerization, and adding oxidized starch, drier, etc. The obtained surface sizing agent can improve the tensile strength, bursting resistance, folding resistance and other properties. However, the sizing agent does not improve the waterproof and oil-proof properties of paper. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] In view of the deficiencies in the prior art, the present invention provides a waterproof sizing agent containing a fluorosilicone polyacrylate waterproofing agent, which improves the waterproof and oil-proof properties of paper.

[0005] (II) Technical solution

[0006] A method for preparing waterproof paper with a waterproof and oil-proof film attached:

[0007] (1) adding a polymerization monomer and a fluorosilicone monomer to toluene, stirring and dissolving, adding azobisisobutyronitrile in a nitrogen atmosphere, stirring for reaction, and removing the solvent by rotary evaporation to obtain a fluorosilicone polyacrylate waterproofing agent;

[0008] The polymerizable monomers include acrylic acid, methacrylic acid, hydroxyethyl acrylate, n-butyl acrylate, n-butyl methacrylate, acryloyloxyethyl trimethyl ammonium chloride, and methacryloyloxyethyl trimethyl ammonium chloride;

[0009] The structural formula of fluorosilicone monomer is: The R group is H or -CH 3。

[0010] (2) Add oxidized starch to water, heat and stir to gelatinize, then cool, add fluorosilicone polyacrylate waterproofing agent, stir and mix to obtain a waterproof sizing agent.

[0011] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 1.5-4g / m 2 ; Dry at 100-120℃ for 3-6min to obtain waterproof paper with a waterproof and oil-proof film.

[0012] Furthermore, the reaction temperature in (1) is 70-85°C, and the reaction time is 3-6h.

[0013] Furthermore, the mass of the fluorosilicone polyacrylate waterproofing agent in (2) is 20-50% of the mass of the oxidized starch.

[0014] Furthermore, the stirring temperature in (2) is 60-75° C., and the stirring time is 10-30 min.

[0015] Furthermore, the molar amount of the fluorosilicone monomer in (1) is 6-15% of the total molar amount of the polymerized monomers.

[0016] Further, the preparation method of fluorosilicone monomer is:

[0017] S1. Add bromoethyl acrylate monomer, 2,2-bis(4-aminophenyl)hexafluoropropane (CAS No. 1095-78-9), potassium carbonate and sodium iodide in a molar ratio of 1:(2-2.2):(0.3-0.42):(0.014-0.02) to toluene, heat to 100-110°C in a nitrogen atmosphere, stir and react for 12-18 hours, concentrate the solution, wash with water, and recrystallize the product with chloroform to obtain 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane.

[0018] S2. Add 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane, trimethylsilyl chloride (CAS No. 75-77-4), and triethylamine in a molar ratio of 1:(2.4-3):(2.4-3) to chloroform, stir and react at 20-30°C for 48-72h, concentrate the solution, wash with water, and recrystallize the product with chloroform to obtain a fluorosilicon monomer. Preparation reaction route:

[0019]

[0020] Furthermore, the bromoethyl acrylate monomer in S1 is 2-bromoethyl acrylate (CAS No. 4823-47-6) or 2-bromoethyl methacrylate (CAS No. 4513-56-8).

[0021] (III) Beneficial technical effects: The present invention uses potassium carbonate and sodium iodide as catalysts to carry out substitution reaction between 2,2-bis(4-aminophenyl)hexafluoropropane and bromoethyl acrylate monomer, and then uses triethylamine as a catalyst to react with trimethylchlorosilane to obtain a new type of fluorosilicone monomer, which is then polymerized with monomers such as acrylic acid to obtain a fluorosilicone polyacrylate waterproofing agent, which is then compounded with oxidized starch to obtain a waterproof sizing agent.

[0022] The present invention uses a waterproof sizing agent to coat and sizing the surface of paper. The sizing agent forms a phenyl fluorosilicone waterproof coating film containing diphenyl hexafluoropropane and methylchlorosilane structures on the surface of the paper. The water contact angle of the paper reaches 11.22-138.4°, the paraffin oil contact angle reaches 83.6-114.2°, and the water absorption is only 10.1-18.6 g / m 2 , showing good waterproof and oil-proof properties. At the same time, after the paper is coated with the sizing agent on the surface, the fluorosilicone polyacrylate polymer can penetrate into the gaps in the paper fibers, playing a role in reinforcing the paper, with a tear strength of 72-81mN and excellent mechanical properties. DETAILED DESCRIPTION

[0023] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as limiting the present invention.

[0024] Example 1

[0025] S1. Add 5mmol of 2-bromoethyl acrylate, 10mmol of 2,2-bis(4-aminophenyl)hexafluoropropane, 1.5mmol of potassium carbonate, and 0.1mmol of sodium iodide to 20mL of toluene, heat to 110°C in a nitrogen atmosphere, stir and react for 12h, concentrate the solution, wash with water, and recrystallize the product with chloroform to obtain 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane. The structural formula is as follows:

[0026]

[0027] S2. Add 5 mmol 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane, 12 mmol trimethylsilyl chloride, and 12 mmol triethylamine in a molar ratio to 25 mL chloroform, stir and react for 72 hours at 20°C, concentrate the solution, wash with water, and recrystallize the product with chloroform to obtain a fluorosilicon monomer. The structural formula is as follows:

[0028] Example 2

[0029] S1. Add 5 mmol of 2-bromoethyl methacrylate, 11 mmol of 2,2-bis(4-aminophenyl)hexafluoropropane, 2.1 mmol of potassium carbonate, and 0.07 mmol of sodium iodide to 25 mL of toluene, heat to 100°C in a nitrogen atmosphere, stir and react for 18 hours, concentrate the solution, wash with water, and recrystallize the product with chloroform to obtain 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane. The structural formula is as follows:

[0030]

[0031] S2. Add 5 mmol 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane, 15 mmol trimethylsilyl chloride and 15 mmol triethylamine in a molar ratio to 30 mL chloroform, stir and react for 48 hours at 30°C, concentrate the solution, wash with water and recrystallize the product with chloroform to obtain a fluorosilicon monomer. The structural formula is as follows:

[0032] Example 3

[0033] (1) 63 mmol acrylic acid, 4 mmol hydroxyethyl acrylate, 28 mmol n-butyl methacrylate, 5 mmol acryloyloxyethyl trimethylammonium chloride, and 6 mmol fluorosilicone monomer (prepared in Example 1) were added to 30 mL of toluene, and after stirring to dissolve, 0.6 mmol azobisisobutyronitrile was added in a nitrogen atmosphere, and the mixture was heated to 75° C. and stirred for 5 h. The solvent was removed by rotary evaporation to obtain a fluorosilicone polyacrylate waterproofing agent.

[0034] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 75° C., add 20 g of fluorosilicone polyacrylate waterproofing agent, stir and mix for 20 min, and obtain a waterproof sizing agent.

[0035] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 1.5 g / m 2 ; Dry at 100℃ for 4 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0036] Example 4

[0037] (1) 65 mmol methacrylic acid, 6 mmol hydroxyethyl acrylate, 25 mmol n-butyl methacrylate, 4 mmol methacryloyloxyethyl trimethylammonium chloride, and 9 mmol fluorosilicone monomer (prepared in Example 2) were added to 30 mL of toluene, and after stirring to dissolve, 0.65 mmol azobisisobutyronitrile was added in a nitrogen atmosphere, and the mixture was heated to 70° C. and stirred for 6 h. The solvent was removed by rotary evaporation to obtain a fluorosilicone polyacrylate waterproofing agent.

[0038] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 60° C., add 30 g of fluorosilicone polyacrylate waterproofing agent, stir and mix for 30 min, and obtain a waterproof sizing agent.

[0039] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 2.4 g / m 2 ; Dry at 100℃ for 6 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0040] Example 5

[0041] (1) 61 mmol acrylic acid, 6 mmol hydroxyethyl acrylate, 30 mmol n-butyl acrylate, 3 mmol methacryloyloxyethyl trimethylammonium chloride, and 12 mmol fluorosilicone monomer (prepared in Example 1) were added to 40 mL of toluene, and after stirring to dissolve, 0.7 mmol azobisisobutyronitrile was added in a nitrogen atmosphere, and the mixture was heated to 85° C. and stirred for 3 h. The solvent was removed by rotary evaporation to obtain a fluorosilicone polyacrylate waterproofing agent.

[0042] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 75° C., add 40 g of fluorosilicone polyacrylate waterproofing agent, stir and mix for 10 min, and obtain a waterproof sizing agent.

[0043] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 3.3 g / m 2 ; Dry at 120℃ for 3 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0044] Example 6

[0045] (1) 66 mmol of acrylic acid, 5 mmol of hydroxyethyl acrylate, 25 mmol of n-butyl methacrylate, 4 mmol of methacryloyloxyethyl trimethylammonium chloride, and 15 mmol of fluorosilicone monomer (prepared in Example 2) were added to 40 mL of toluene, and after stirring to dissolve, 0.7 mmol of azobisisobutyronitrile was added in a nitrogen atmosphere, and the mixture was heated to 85° C. and stirred for 4 h. The solvent was removed by rotary evaporation to obtain a fluorosilicone polyacrylate waterproofing agent.

[0046] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 75° C., add 50 g of fluorosilicone polyacrylate waterproofing agent, stir and mix for 20 min, and obtain a waterproof sizing agent.

[0047] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 4g / m 2; Dry at 100℃ for 6 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0048] Comparative Example 1

[0049] (1) Add 63 mmol of acrylic acid, 4 mmol of hydroxyethyl acrylate, 28 mmol of n-butyl methacrylate, and 5 mmol of acryloyloxyethyl trimethylammonium chloride to 30 mL of toluene, stir to dissolve, then add 0.6 mmol of azobisisobutyronitrile in a nitrogen atmosphere, heat to 75° C., stir to react for 5 h, and remove the solvent by rotary evaporation to obtain a polyacrylate waterproofing agent.

[0050] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 75° C., add 20 g of polyacrylate waterproofing agent, stir and mix for 20 min, and obtain a waterproof sizing agent.

[0051] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 1.5 g / m 2 ; Dry at 100℃ for 4 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0052] Comparative Example 2

[0053] (1) Add 63 mmol acrylic acid, 4 mmol hydroxyethyl acrylate, 28 mmol n-butyl methacrylate, 5 mmol acryloyloxyethyl trimethylammonium chloride, and 6 mmol vinyl triethoxysilane to 30 mL of toluene, stir to dissolve, then add 0.6 mmol azobisisobutyronitrile in a nitrogen atmosphere, heat to 75° C., stir to react for 5 h, and remove the solvent by rotary evaporation to obtain a silicon-containing polyacrylate waterproofing agent.

[0054] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 75° C., add 20 g of a silicon-containing polyacrylate waterproofing agent, stir and mix for 20 min, and obtain a waterproof sizing agent.

[0055] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 1.5 g / m 2 ; Dry at 100℃ for 4 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0056] Comparative Example 3

[0057] (1) Add 63 mmol of acrylic acid, 4 mmol of hydroxyethyl acrylate, 28 mmol of n-butyl methacrylate, 5 mmol of acryloyloxyethyl trimethylammonium chloride, and 6 mmol of hexafluorobutyl methacrylate to 30 mL of toluene, stir and dissolve, then add 0.6 mmol of azobisisobutyronitrile in a nitrogen atmosphere, heat to 75° C. and stir to react for 5 h, then remove the solvent by rotary evaporation to obtain a fluorinated polyacrylate waterproofing agent.

[0058] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 75° C., add 20 g of fluorinated polyacrylate waterproofing agent, stir and mix for 20 min, and obtain a waterproof sizing agent.

[0059] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 1.5 g / m 2 ; Dry at 100℃ for 4 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0060] Comparative Example 4

[0061] (1) Add 63 mmol acrylic acid, 4 mmol hydroxyethyl acrylate, 28 mmol n-butyl methacrylate, 5 mmol acryloyloxyethyl trimethylammonium chloride, 3 mmol hexafluorobutyl methacrylate, and 3 mmol vinyl triethoxysilane to 30 mL of toluene, stir to dissolve, then add 0.6 mmol azobisisobutyronitrile in a nitrogen atmosphere, heat to 75° C., stir to react for 5 h, and remove the solvent by rotary evaporation to obtain a fluorosilicone polyacrylate waterproofing agent.

[0062] (2) Add 100 g of oxidized starch to 800 mL of water, heat to 95° C., stir and gelatinize for 30 min, then cool to 75° C., add 20 g of fluorosilicone polyacrylate waterproofing agent, stir and mix for 20 min, and obtain a waterproof sizing agent.

[0063] (3) Apply waterproof sizing agent to the surface of paper, with a coating amount of 1.5 g / m 2 ; Dry at 100℃ for 4 minutes to obtain waterproof paper with a waterproof and oil-proof film.

[0064] Comparative Example 5 is a paper that has not been surface coated with a sizing agent.

[0065] According to the method of ASTM D 724-1999 (2003), the water contact angle of the paper surface was tested using a wetting angle tester. The test medium was replaced with paraffin oil, and the paraffin oil contact angle of the paper surface was tested.

[0066] Table 1 Paper surface contact angle test

[0067]

[0068]

[0069] The water absorption of paper per unit area was tested according to the Kebo value determination method in GB / T 1540-2002 standard, and the water absorption time was 30s.

[0070] The tear resistance of paper is tested according to GB / T 455-2002 standard.

[0071] <![CDATA[Water absorption (g / m 2 )]]> Tear strength(mN) Example 1 18.6 75 Example 2 15.8 81 Example 3 12.9 80 Example 4 10.1 72 Comparative Example 1 49.5 68 Comparative Example 2 33.3 73 Comparative Example 3 30.2 67 Comparative Example 4 24.5 71 Comparative Example 5 71.3 53

[0072] As shown in Table 1 and Table 2, in Examples 1-4, the waterproof sizing agent is used to coat the paper surface, and a phenyl fluorosilicone waterproof coating film containing diphenyl hexafluoropropane and methylchlorosilane structure is formed on the paper surface, the water contact angle reaches 11.22-138.4°, the paraffin oil contact angle reaches 83.6-114.2°, and the water absorption is only 10.1-18.6 g / m 2 , showing good waterproof and oil-proof properties. At the same time, after the paper is coated with sizing agent, the tear strength reaches 72-81mN.

[0073] The paper of comparative example 5 was not coated with sizing agent on the surface, and the water absorption reached 71.3 g / m 2 , the tearing strength is only 53mN.

[0074] Compared with Example 1, the polyacrylate waterproofing agent of Comparative Example 1 does not contain fluorosilicone monomer, and cannot form a phenyl fluorosilicone coating on the paper surface. The water contact angle and paraffin oil contact angle are low, and the waterproof and oil-proof performance is poor. In addition, the tear strength is only 68 mN, which may be because the polyacrylate waterproofing agent does not contain a rigid benzene ring structure, resulting in low mechanical properties of the coating.

[0075] In Comparative Example 2, only common vinyl triethoxysilane was added as a silicon-containing monomer, and the waterproofing agent did not contain a fluorine-containing group. In Comparative Example 3, only common hexafluorobutyl methacrylate was added as a fluorine-containing monomer, and the waterproofing agent did not contain a silicon-containing group. The water contact angle and paraffin oil contact angle of the paper after sizing were low, and the waterproof and oil-proof properties were poor. The tear resistance was low.

[0076] Vinyl triethoxysilane and hexafluorobutyl methacrylate were added to the waterproofing agent of Comparative Example 4. However, after sizing the paper surface, the water contact angle and tear strength were lower than those of Example 1. This may be because the waterproofing agent of Example 1 contains a hydrophobic and rigid benzene ring structure, which is beneficial to reducing the water contact angle of the paper surface and improving the tear strength.

Claims

1. A method for preparing waterproof paper with a waterproof and oil-proof film, characterized in that: The preparation method is: (1) adding a polymerization monomer and a fluorosilicone monomer to toluene, stirring and dissolving, adding azobisisobutyronitrile in a nitrogen atmosphere, stirring for reaction, and removing the solvent by rotary evaporation to obtain a fluorosilicone polyacrylate waterproofing agent; The polymerizable monomers include acrylic acid, methacrylic acid, hydroxyethyl acrylate, n-butyl acrylate, n-butyl methacrylate, acryloyloxyethyl trimethyl ammonium chloride, and methacryloyloxyethyl trimethyl ammonium chloride; The structural formula of the fluorosilicone monomer is: The R group is H or -CH3; (2) adding oxidized starch to water, heating and stirring to gelatinize, then cooling, adding fluorosilicone polyacrylate waterproofing agent, stirring and mixing to obtain a waterproof sizing agent; (3) Applying a waterproof sizing agent to the surface of paper and drying the paper to obtain waterproof paper with a waterproof and oil-proof film.

2. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 1, characterized in that: The reaction temperature in (1) is 70-85°C and the reaction time is 3-6h.

3. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 1, characterized in that: The mass of the fluorosilicone polyacrylate waterproofing agent in (2) is 20-50% of the mass of the oxidized starch.

4. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 1, characterized in that: The stirring temperature in (2) is 60-75°C and the stirring time is 10-30 min.

5. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 1, characterized in that: The coating amount of the sizing agent in (3) is 1.5-4 g / m 2 ; The drying temperature is 100-120℃ and the time is 3-6min.

6. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 1, characterized in that: The molar amount of the fluorosilicon monomer in (1) is 6-15% of the total molar amount of the polymerized monomers.

7. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 2, characterized in that: The preparation method of the fluorosilicone monomer is: S1. Add bromoethyl acrylate monomer, 2,2-bis(4-aminophenyl)hexafluoropropane, potassium carbonate and sodium iodide in a molar ratio of 1:(2-2.2):(0.3-0.42):(0.014-0.02) to toluene, heat to 100-110° C. in a nitrogen atmosphere, stir and react for 12-18 hours, concentrate the solution, wash with water and recrystallize the product with chloroform to obtain 2,2-bis(4-acrylate ethylaminophenyl)hexafluoropropane; S2. Add 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane, trimethylsilyl chloride and triethylamine to chloroform, stir to react, concentrate the solution, wash with water, and recrystallize the product with chloroform to obtain a fluorosilicon monomer.

8. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 7, characterized in that: The bromoethyl acrylate monomer in S1 is 2-bromoethyl acrylate or 2-bromoethyl methacrylate.

9. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 7, characterized in that: The molar ratio of 2,2-bis(4-acrylateethylaminophenyl)hexafluoropropane, trimethylsilyl chloride and triethylamine in S2 is 1:(2.4-3):(2.4-3).

10. The method for preparing waterproof paper with attached waterproof and oil-proof film according to claim 7, characterized in that: The reaction temperature in S2 is 20-30°C and the reaction time is 48-72h.

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