Nanocellulose-based composite oil-absorbing paper and preparation method thereof

Abstract

The invention relates to the technical field of preparation of specialty paper, and discloses nanocellulose-based composite oil-absorbing paper and a preparation method thereof. The preparation method comprises the following steps: (1) adding water into plant fiber, nano cellulose and an auxiliary agent, and shearing at a high speed in a wall breaking machine to obtain a mixed raw material suspension; the obtained mixed raw material suspension is made into paper, drying is conducted, and the plant fiber paper base containing the nanocellulose is obtained. And (2) adding the cotton nanocellulose fibrils prepared by grinding the ultrafine particles into a reactor, adding citric acid to adjust the pH value, adding a modifier under a stirring condition, reacting for a certain time at a proper temperature, and washing the reaction product to obtain the modified nanocellulose. And (3) preparing the modified nanocellulose, beeswax and an auxiliary agent into an emulsion, and adding the emulsion into the paper base prepared in the step (1) in manners of coating, spraying, dipping and the like to obtain the oil-absorbing paper which is relatively high in mechanical strength, has good oil-absorbing capacity, does not absorb water and is degradable.

Description

Technical Field

[0001] The invention relates to the technical field of special paper preparation, and in particular to a nano-cellulose-based composite oil-absorbing paper and a preparation method thereof. Background Art

[0002] In daily life, especially in summer, people tend to secrete oil on their faces, and these oils will remain on the face, which is easily contaminated by dust and clogs the pores. In order to solve this problem, oil-absorbing paper came into being. The common oil-absorbing paper on the market is mainly made of plant fibers such as cotton and linen, and there is also an oil-absorbing film made of high molecular polymers.

[0003] The cheaper plant fiber oil-absorbing paper on the market is mainly made of cotton, hemp and other wood pulp. Although this kind of oil-absorbing paper has a good adsorption effect, its quantitative content is relatively low (generally 10-20g / cm 2 ), the mechanical strength is very poor, and it is easy to break during use, affecting the consumer experience. In addition, in addition to removing facial oil, this type of oil-absorbing paper also removes moisture, causing dryness and sensitivity on the face. The more expensive oil-absorbing film is obtained by extruding a porous structure of high-molecular polymer materials such as polypropylene, polyethylene and polybutylene. This type of oil-absorbing film not only has a good adsorption effect, but also does not remove facial moisture, and has strong mechanical strength and is not easy to damage. However, its main problem is that it is difficult to degrade and causes pollution to the environment. Therefore, inventing an oil-absorbing paper that has strong mechanical strength, good oil absorption ability, is non-absorbent and degradable is a problem that needs to be solved in this field. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the object of the present invention is to provide a composite oil-absorbing paper made of nanocellulose and plant fibers, which has high mechanical strength, is hydrophobic and oleophilic, and is green.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned nanocellulose-based plant fiber composite oil-absorbing paper.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A nanocellulose-based plant fiber composite oil-absorbing paper is prepared from nanocellulose fibrils, modified nanocellulose fibrils, plant fibers, beeswax, a modifier and an auxiliary agent.

[0008] The method for preparing the nanocellulose-based plant fiber composite oil-absorbing paper comprises the following steps:

[0009] (1) adding water to plant fiber, nanocellulose and an additive and subjecting them to high-speed shearing in a wall-breaking machine to obtain a mixed raw material suspension; sheeting the obtained mixed raw material suspension into paper, and drying it to obtain a plant fiber paper base containing nanocellulose.

[0010] (2) Adding the cotton nanocellulose fibrils prepared by ultrafine particle grinding into a reactor, adding citric acid to adjust the pH, adding a modifier under stirring conditions, reacting at an appropriate temperature for a certain period of time, and washing the reaction product to obtain modified nanocellulose.

[0011] (3) (un)modified nanocellulose, beeswax and additives are prepared into an emulsion, which is added to the paper base prepared in (1) by coating, spraying, dipping, etc. to obtain a mixed oil-absorbing paper of nanocellulose and plant fibers.

[0012] The plant fibers in step (1) are mainly cotton fibers, hemp fibers and other wood pulp fibers.

[0013] The nanocellulose in step (1) refers to cotton nanocellulose fibrils and bamboo nanocellulose fibrils prepared by ultrafine particle grinding method and enzymatic hydrolysis method; the content of the nanocellulose fibrils is 1wt% to 5wt% of the paper weight.

[0014] The auxiliary agents in step (1) are mainly polyamide epichlorohydrin resin (PAE) and hydroxymethyl silicone oil; wherein the content of PAE is 0.5% to 5% of the paper weight, and the content of hydroxymethyl silicone oil is 0.5% to 5% of the paper weight; and the high-speed shearing time is 3 to 6 minutes.

[0015] The modifier in step (2) is mainly hexadecyltrimethoxysilane, phenyltrimethoxysilane or methyltrimethoxysilane; the reaction temperature is 26-60° C.; and the reaction time is 4-8 hours.

[0016] The mass ratio of nanocellulose, citric acid and modifier in step (2) is 1:(0.5-1):(1-3).

[0017] The modified nanocellulose in step (3) is mainly cotton nanocellulose fibrils modified by silane; its content in the coating preparation is 0.5wt% to 1wt%.

[0018] The beeswax in step (3) is mainly bleached white beeswax; its content in the coating preparation is 5wt% to 10wt%.

[0019] The auxiliary agents in step (3) are mainly glycerol and glycerol stearate; the glycerol content is 0.5wt% to 1wt% of the coating, and the glycerol stearate content is 0.5wt% to 1wt% of the coating.

[0020] The prepared nanocellulose-based plant fiber composite oil-absorbing paper has a basis weight of 15 to 20 g / m 2 ; The amount of coating liquid added is 10 to 15 wt% of the paper weight.

[0021] The principle of the invention is that nanocellulose and plant fibers will form a three-dimensional network structure during the mixing process, thereby improving the strength of paper. Nanocellulose itself is hydrophilic, and it is modified to have hydrophobic and lipophilic properties, and an emulsion is prepared with beeswax, which acts as a stabilizer and is coated on the surface of paper to give it hydrophobicity.

[0022] The oil-absorbing paper obtained by the invention has a water contact angle of 114° to 130°, an oil contact angle of 28° to 38°, a tensile strength of 46 to 65 kN / m, and an oil absorption capacity of about 1.34 to 1.88 times of its own mass.

[0023] Compared with the prior art, the present invention has the following advantages and effects:

[0024] (1) The oil-absorbing paper obtained by the present invention has good mechanical strength when in use, will not be damaged during use, and has a good feeling of use.

[0025] (2) The oil-absorbing paper obtained by the present invention not only has good softness and smoothness, but also retains moisture while carrying oil during use, so that the face remains moisturized.

[0026] (3) The nanocellulose used in the present invention is a green and environmentally friendly biomass-based raw material with a high aspect ratio. By compounding with plant fibers to form a three-dimensional network structure, the mechanical strength of paper can be improved.

[0027] (4) The nanocellulose used in the present invention is modified by silanization to impart hydrophobic and lipophilic properties, and can be used as a stabilizer to prepare an emulsion with beeswax, and added to the surface of paper to impart hydrophobicity.

[0028] Figure 1 This is a test result diagram of the water-oil contact angle of the oil-absorbing paper of Comparative Example 1 of the present invention.

[0029] Figure 2 This is a test result diagram of the water-oil contact angle of the oil-absorbing paper of Comparative Example 2 of the present invention.

[0030] Figure 3 This is a test result diagram of the water-oil contact angle of the oil-absorbing paper of Example 1 of the present invention.

[0031] Figure 4 This is a graph showing the water-oil contact angle test results of the oil-absorbing paper of Example 2 of the present invention.

[0032] Figure 5 This is a graph showing the water-oil contact angle test results of the oil-absorbing paper of Example 3 of the present invention.

[0033] Figure 6 This is a graph showing the test results of the water-oil contact angle of the oil-absorbing paper of Example 4 of the present invention.

[0034] Figure 7 This is a graph showing the water-oil contact angle test results of the oil-absorbing paper of Example 5 of the present invention.

[0035] Figure 8 It is a graph showing the tensile strength test results of Comparative Examples 1 to 2 and Examples 1 to 5 of the present invention.

[0036] Fig. 9 It is a graph showing the oil absorption capacity test results of Comparative Examples 1 to 2 and Examples 1 to 5 of the present invention. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0038] The modified nanocellulose described in the following Examples 1 to 5 is prepared by the following method: cotton nanocellulose, citric acid and a modifier hexadecyltrimethoxysilane are weighed in a mass ratio of 1:0.5:(1 to 3); citric acid is added to the cotton nanocellulose to adjust the pH to acidic, and then the modifier is added, and the reaction is stirred at room temperature for (4 to 8) hours; the obtained reactant is centrifuged and washed several times with ethanol and water to remove the unreacted modifier and citric acid, and finally the modified cotton nanocellulose is obtained.

[0039] Comparative Example 1

[0040] (1) Add cotton fiber, cotton nanocellulose, bamboo nanocellulose, PAE and hydroxymethyl silicone oil into a wall breaking machine and high-speed shear for 3 minutes. The total amount of cotton nanocellulose and bamboo nanocellulose added is 3wt%, the ratio is 1:1; the total amount of PAE and hydroxymethyl silicone oil added is 5wt%, the ratio is 2:3; after high-shear dispersion, the papermaking weight is 20g / m 2 Paper base.

[0041] (2) Unmodified nanocellulose, beeswax, glycerol and glycerol fatty acid ester were prepared into an emulsion in a mass ratio of 1:10:1:1.

[0042] (3) Adding the prepared emulsion to the surface of the paper base prepared in (1) by coating to prepare a nanocellulose-based composite oil-absorbing paper.

[0043] The oil absorbing paper obtained in this comparative example was tested for water-oil contact angle and tensile strength. The results are as follows: Figure 1 and Figure 8 As shown; its water contact angle reaches 115°, oil contact angle is 34°; tensile strength: 47.37kN / m; oil absorption capacity is about 1.88 times of its own mass.

[0044] Comparative Example 2

[0045] (1) Add cotton fiber, cotton nanocellulose, bamboo nanocellulose, PAE and hydroxymethyl silicone oil into a wall breaking machine and high-speed shear for 5 minutes. The total amount of cotton nanocellulose and bamboo nanocellulose added is 5wt%, the ratio is 1:1, the total amount of PAE and hydroxymethyl silicone oil added is 3wt%, the ratio is 2:1, and after high-shear dispersion, the papermaking weight is 20g / m 2 Paper base.

[0046] (2) Unmodified nanocellulose, beeswax, glycerol and glycerol fatty acid ester were prepared into an emulsion in a mass ratio of 1:10:1:1.

[0047] (3) Adding the prepared emulsion to the surface of the paper base prepared in (1) by coating to prepare a nanocellulose-based composite oil-absorbing paper.

[0048] The oil absorbing paper obtained in this comparative example was tested for water-oil contact angle and tensile strength. The results are as follows: Figure 7 and Figure 8 As shown; its water contact angle reaches 114°, oil contact angle 29°; tensile strength: 52.37kN / m; oil absorption capacity is about 1.38 times of its own mass.

[0049] Example 1

[0050] (1) Add cotton fiber, cotton nanocellulose, bamboo nanocellulose, PAE and hydroxymethyl silicone oil into a wall breaking machine and high-speed shear for 3 minutes. The total amount of cotton nanocellulose and bamboo nanocellulose added is 3wt%, the ratio is 1:1, the total amount of PAE and hydroxymethyl silicone oil added is 5wt%, the ratio is 2:3, and after high-shear dispersion, the papermaking weight is 20g / m 2 Paper base.

[0051] (2) Modified nanocellulose, beeswax, glycerol and glycerol fatty acid ester are prepared into an emulsion in a mass ratio of 1:10:1:1.

[0052] (3) Adding the prepared emulsion to the surface of the paper base prepared in (1) by coating to prepare a nanocellulose-based composite oil-absorbing paper.

[0053] The oil absorbing paper obtained in this example was tested for water-oil contact angle and tensile strength. The results are as follows: Figure 2 and Figure 8 As shown; its water contact angle reaches 126°, and the oil contact angle is 38°; tensile strength: 46.33kN / m; the oil absorption capacity is about 1.69 times of its own mass.

[0054] Example 2

[0055] (1) Add cotton fiber, cotton nanocellulose, bamboo nanocellulose, PAE and hydroxymethyl silicone oil into a wall breaking machine and high-speed shear for 3 minutes. The total amount of cotton nanocellulose and bamboo nanocellulose added is 5wt%, the ratio is 1:1, the total amount of PAE and hydroxymethyl silicone oil added is 5wt%, the ratio is 2:3, and after high-shear dispersion, the papermaking weight is 20g / m 2 Paper base.

[0056] (2) Modified nanocellulose, beeswax, glycerol and glycerol fatty acid ester are prepared into an emulsion in a mass ratio of 1:10:1:1.

[0057] (3) Adding the prepared emulsion to the surface of the paper base prepared in (1) by coating to prepare a nanocellulose-based composite oil-absorbing paper.

[0058] The oil absorbing paper obtained in this example was tested for water-oil contact angle and tensile strength. The results are as follows: Figure 3 and Figure 8 As shown; its water contact angle reaches 123°, oil contact angle is 34°; tensile strength: 56.1kN / m; oil absorption capacity is about 1.34 times of its own mass.

[0059] Example 3

[0060] (1) Add cotton fiber, cotton nanocellulose, bamboo nanocellulose, PAE and hydroxymethyl silicone oil into a wall breaking machine and high-speed shear for 5 minutes. The total amount of cotton nanocellulose and bamboo nanocellulose added is 3wt%, the ratio is 1:1, the total amount of PAE and hydroxymethyl silicone oil added is 3wt%, the ratio is 1:2, and after high-shear dispersion, the papermaking weight is 20g / m 2 Paper base.

[0061] (2) Modified nanocellulose, beeswax, glycerol and glycerol fatty acid ester are prepared into an emulsion in a mass ratio of 1:10:1:1.

[0062] (3) Adding the prepared emulsion to the surface of the paper base prepared in (1) by coating to prepare a nanocellulose-based composite oil-absorbing paper.

[0063] The oil absorbing paper obtained in this example was tested for water-oil contact angle and tensile strength. The results are as follows: Figure 4 and Figure 8 As shown; its water contact angle reaches 130°, oil contact angle 28°; tensile strength: 51.44kN / m; oil absorption capacity is about 1.73 times of its own mass.

[0064] Example 4

[0065] (1) Add cotton fiber, cotton nanocellulose, bamboo nanocellulose, PAE and hydroxymethyl silicone oil into a wall breaking machine and high-speed shear for 5 minutes. The total amount of cotton nanocellulose and bamboo nanocellulose added is 3wt%, the ratio is 1:1, the total amount of PAE and hydroxymethyl silicone oil added is 3wt%, the ratio is 2:1, and after high-shear dispersion, the papermaking weight is 20g / m 2 Paper base.

[0066] (2) Modified nanocellulose, beeswax, glycerol and glycerol fatty acid ester are prepared into an emulsion in a mass ratio of 1:10:1:1.

[0067] (3) Adding the prepared emulsion to the surface of the paper base prepared in (1) by coating to prepare a nanocellulose-based composite oil-absorbing paper.

[0068] The oil absorbing paper obtained in this example was tested for water-oil contact angle and tensile strength. The results are as follows: Figure 5 and Figure 8 As shown; its water contact angle reaches 121°, and the oil contact angle is 35°; tensile strength: 50.32kN / m; the oil absorption capacity is about 1.54 times of its own mass.

[0069] Example 5

[0070] (1) Add cotton fiber, cotton nanocellulose, bamboo nanocellulose, PAE and hydroxymethyl silicone oil into a wall breaking machine and high-speed shear for 5 minutes. The total amount of cotton nanocellulose and bamboo nanocellulose added is 5wt%, the ratio is 1:1, the total amount of PAE and hydroxymethyl silicone oil added is 3wt%, the ratio is 1:2, and after high-shear dispersion, the papermaking weight is 20g / m 2 Paper base.

[0071] (2) Modified nanocellulose, beeswax, glycerol and glycerol fatty acid ester are prepared into an emulsion in a mass ratio of 1:10:1:1.

[0072] (3) Adding the prepared emulsion to the surface of the paper base prepared in (1) by coating to prepare a nanocellulose-based composite oil-absorbing paper.

[0073] The oil absorbing paper obtained in this example was tested for water-oil contact angle and tensile strength. The results are as follows: Figure 6 and Figure 8 As shown; its water contact angle reaches 121°, oil contact angle is 35°; tensile strength: 65.24kN / m; oil absorption capacity is about 1.45 times of its own mass.

[0074] From the results of the above comparative examples and embodiments, it can be seen that the nanocellulose-based composite oil-absorbing paper of the present invention has good hydrophobicity and lipophilicity, and the hydrophobic effect of the paper using modified nanocellulose is better than that of the paper not using modified nanocellulose, and the mechanical strength of the paper after adding nanocellulose is improved.

[0075] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A nanocellulose-based composite oil-absorbing paper, characterized in that: The following steps are involved: A nanocellulose-based plant fiber composite oil-absorbing paper is prepared from nanocellulose fibrils, modified nanocellulose fibrils, plant fibers, beeswax, a modifier and an auxiliary agent. (1) adding water to plant fiber, nanocellulose and an additive and subjecting them to high-speed shearing in a wall-breaking machine to obtain a mixed raw material suspension; sheeting the obtained mixed raw material suspension into paper, and drying it to obtain a plant fiber paper base containing nanocellulose. (2) Adding the cotton nanocellulose fibrils prepared by ultrafine particle grinding into a reactor, adding citric acid to adjust the pH, adding a modifier under stirring conditions, reacting at an appropriate temperature for a certain period of time, and washing the reaction product to obtain modified nanocellulose. (3) (un)modified nanocellulose, beeswax and additives are prepared into an emulsion, which is added to the paper base prepared in (1) by coating, spraying, dipping, etc. to obtain a mixed oil-absorbing paper of nanocellulose and plant fibers.

2. The plant fibers in step (1) according to claim 1 are mainly cotton fibers, hemp fibers and other wood pulp fibers; the nanocellulose refers to cotton nanocellulose fibrils and bamboo nanocellulose fibrils prepared by ultrafine particle grinding and enzymatic hydrolysis; the content of the nanocellulose fibrils is 1wt% to 5wt% of the paper weight.

3. The nanocellulose-based composite oil-absorbing paper according to claim 1, characterized in that: The auxiliary agents in step (1) are mainly PAE and hydroxymethyl silicone oil; wherein the content of PAE is 0.5% to 5% of the paper weight, and the content of hydroxymethyl silicone oil is 0.5% to 5% of the paper weight; and the high-speed shearing time is 3 to 6 minutes.

4. The nanocellulose-based composite oil-absorbing paper according to claim 1, characterized in that: The modifier in step (2) is mainly hexadecyltrimethoxysilane, phenyltrimethoxysilane or methyltrimethoxysilane; the reaction temperature is 26-60° C.; and the reaction time is 4-8 hours.

5. The nanocellulose-based composite oil-absorbing paper according to claim 1, characterized in that: The mass ratio of nanocellulose, citric acid and modifier in step (2) is 1:(0.5-1):(1-3).

6. The nanocellulose-based composite oil-absorbing paper according to claim 1, characterized in that: The modified nanocellulose in step (3) is mainly cotton nanocellulose fibrils modified by silane; Its content in coating preparation is 0.5wt% to 1wt%.

7. The nanocellulose-based composite oil-absorbing paper according to claim 1, characterized in that: The beeswax in step (3) is mainly bleached white beeswax; Its content in coating preparation is 5wt% to 10wt%.

8. The nanocellulose-based composite oil-absorbing paper according to claim 1, characterized in that: The auxiliary agents in step (3) are mainly glycerol and glycerol stearate; the glycerol content is 0.5wt% to 1wt% of the coating, and the glycerol stearate content is 0.5wt% to 1wt% of the coating.

9. A nanocellulose-based composite oil-absorbing paper according to any one of claims 1 to 8, characterized in that: The paper basis weight of the nanocellulose-based composite oil-absorbing paper is 15 to 20 g / m 2 ; The amount of coating liquid added is 10 to 15 wt% of the paper weight.

10. The method for preparing a nanocellulose-based composite oil-absorbing paper according to claim 9, characterized in that: The water contact angle of the oil-absorbing paper reaches 114° to 130°; the oil contact angle is 28° to 38°; the tensile strength reaches 46 to 65 kN / m; and the oil absorption capacity is about 1.34 to 1.88 times of its own weight.

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