阅读说明：本技术 一种疏水增强型书画纸及其制备方法 (Hydrophobic enhanced painting and calligraphy paper and preparation method thereof ) 是由 赵会芳 马超 沙力争 张学金 邱苏鹏 于 2019-11-05 设计创作，主要内容包括：本发明公开了一种疏水增强型书画纸及其制备方法,属于造纸技术领域。本发明提供的疏水增强型书画纸,包括书画纸、形成于所述书画纸表面的疏水改性纳米纤维素涂层,其中：所述疏水改性纳米纤维素是先用2,2,6,6-四甲基哌啶氧化物氧化预处理纤维素,得到带有羧基的纤维素,然后进行高压均质得到纳米纤维素；再采用两步法疏水改性纳米纤维素,第一步用戊二酸酐、丙酸酐作为复合酸酐为酯化改性纳米纤维素的试剂；第二步用1-三癸胺和正癸胺通过静电吸附作用与酯化改性的纳米纤维素反应形成络合物。由于本发明采用的纳米纤维素尺寸小,更容易沉积在纸张表面或者渗透孔隙,可增强纸的水蒸气阻隔性能以及疏水性,且可显著改善书画纸的强度性能。(The invention discloses hydrophobic enhanced painting and calligraphy paper and a preparation method thereof, and belongs to the technical field of papermaking. The invention provides hydrophobic enhanced painting and calligraphy paper, which comprises painting and calligraphy paper and a hydrophobic modified nano-cellulose coating formed on the surface of the painting and calligraphy paper, wherein the hydrophobic modified nano-cellulose coating comprises the following components in percentage by weight: the hydrophobic modified nano-cellulose is prepared by oxidizing and pretreating cellulose by using 2,2,6, 6-tetramethyl piperidine oxide to obtain cellulose with carboxyl, and then homogenizing under high pressure to obtain nano-cellulose; hydrophobic modification of the nano-cellulose is carried out by adopting a two-step method, and glutaric anhydride and propionic anhydride are used as composite anhydride as reagents for esterifying and modifying the nano-cellulose in the first step; and in the second step, 1-tridecylamine and n-decylamine are used for reacting with the nano cellulose modified by esterification through electrostatic adsorption to form a complex. The nanocellulose adopted by the invention has small size, is easier to deposit on the surface of paper or permeate pores, can enhance the water vapor barrier property and hydrophobicity of the paper, and can obviously improve the strength property of the writing and painting paper.)

1. The hydrophobic enhanced painting and calligraphy paper is characterized in that: comprises painting and calligraphy paper and a hydrophobic modified nano-cellulose coating formed on the surface of the painting and calligraphy paper.

2. The hydrophobically reinforced writing and painting paper of claim 1, wherein the paper is characterized byIn the following steps: the weight of the hydrophobic enhanced painting and calligraphy paper is 40-60g/m²。

3. The hydrophobically reinforced writing and painting paper according to claim 1, wherein: the hydrophobic modified nano-cellulose is prepared by the following method, comprising the following steps:

(1) crushing and uniformly stirring fiber slurry, then carrying out oxidation pretreatment on the fiber slurry by adopting a TEMPO/NaClO/NaBr system, and carrying out suction filtration and washing to obtain oxidized cellulose;

(2) preparing the oxidized cellulose obtained in the step (1) into a suspension with the concentration of 1-2%, and then carrying out high-pressure homogenization treatment to obtain a nano cellulose suspension;

(3) rotationally evaporating the nano-cellulose suspension obtained in the step (2) to obtain gel-like nano-cellulose; then adding N-N-dimethylformamide into the gel-like nano-cellulose according to the proportion, uniformly dispersing by ultrasonic, heating to 80-90 ℃, and stirring at constant temperature for 4-6 h; after stirring, continuously adding glutaric anhydride, propionic anhydride and 4-dimethylamino pyridine according to the proportion, and obtaining reaction liquid 1 after ultrasonic dispersion is uniform; heating the reaction solution 1 to 80-120 ℃ for constant-temperature reaction for 4-8h, cooling after the reaction is finished, centrifuging and washing a product to obtain esterified modified nano-cellulose;

(4) respectively adding a 1-tridecylamine solution and an n-decylamine solution into the esterified and modified nanocellulose obtained in the step (3) according to the ratio, uniformly mixing to obtain a reaction solution 2, adjusting the pH value of the reaction solution 2 to be neutral, and stirring at constant temperature of 40-80 ℃ for reaction for 2-6 hours; and after the reaction is finished, centrifuging and washing the product, and finally performing dialysis separation treatment to obtain the hydrophobic modified nano-cellulose.

4. The hydrophobically reinforced writing and painting paper according to claim 3, wherein: the fiber pulp in the step (1) is any one of wood pulp, cotton pulp, hemp pulp, bamboo pulp and reed pulp.

5. The hydrophobically reinforced writing and painting paper according to claim 3, wherein: in the fiber slurry obtained in the step (1), the mass ratio of oven-dried fibers, 2,6, 6-tetramethylpiperidine oxide, sodium bromide and sodium hypochlorite is 1: 0.01-0.02: 0.05-0.2: 6-10.

6. The hydrophobically reinforced writing and painting paper according to claim 3, wherein: the dosage ratio of the oven-dried nano-cellulose to the N-N-dimethylformamide in the nano-cellulose water suspension in the step (3) is 1-2 parts by mass: 60-100 parts by volume, wherein: the mass portion and the volume portion are as follows: ml is used as a reference.

7. The hydrophobically reinforced writing and painting paper according to claim 3, wherein: the mass ratio of the oven-dried nano-cellulose to the glutaric anhydride, the propionic anhydride and the 4-dimethylamino pyridine in the nano-cellulose water suspension in the step (3) is 1: 20: 20: 0.6.

8. the hydrophobically reinforced writing and painting paper according to claim 3, wherein: the mass ratio of the esterified and modified nano-cellulose to the 1-tridecylamine in the 1-tridecylamine solution to the n-decylamine in the n-decylamine solution is 1: 0.1-0.45: 0.1-0.45.

9. The process for the preparation of hydrophobically reinforced writing and painting papers as claimed in any of claims 1 to 8, wherein: the method specifically comprises the steps of preparing hydrophobic modified nano-cellulose into a sizing solution with the concentration of 2-8%, coating the sizing solution on the surface of the painting and calligraphy paper, and drying the painting and calligraphy paper in an oven.

10. The method of making hydrophobically reinforced writing and painting paper as claimed in claim 9, wherein: the mass ratio of the absolutely dry fibers of the painting and calligraphy paper to the absolutely dry hydrophobically modified nanocellulose is 1: 0.01-0.03.

Technical Field

The invention belongs to the technical field of papermaking, and particularly relates to hydrophobic enhanced painting and calligraphy paper and a preparation method thereof.

Background

The differential water absorbability and the ink absorbability of the painting and calligraphy paper become one of the key links of the production of art paper. As for the existing writing and painting paper, plant fibers are used as materials, and the existing writing and painting paper is not treated too much, so that the existing writing and painting paper is easy to absorb moisture and mildew when the humidity is high. In addition, the writing and painting paper is not strong and is easy to break, which is a problem to be paid special attention in production. Therefore, the painting and calligraphy paper in the prior art mainly has the following technical problems:

1. reinforcing problem of painting and calligraphy paper

The fiber raw materials used by the painting and calligraphy paper are complex, the painting and calligraphy paper is generally made of bark fibers, bamboo fibers and grass fibers, the tension of the fibers is not strong enough, so the fastness is poor, the painting and calligraphy paper has poor tensile strength, folding strength and other strength performances, and the painting and calligraphy paper is easy to break in the processes of painting and calligraphy, storage or display, and causes serious loss. If other chemical reinforcing agents are used, the writing effect of the writing and painting paper is influenced.

2. Water absorption and ink absorption of painting and calligraphy paper

The existing painting and calligraphy paper has relatively single water absorption and ink absorption. The water absorption and the ink absorption are generally controlled by an internal sizing mode, the method is often poor in uniformity and can cause the expressive force of the writing and painting paper to be poor, artists or artistic enthusiasts pursue the expressive force in individuality and microcosmic aspects, the water absorption and the ink absorption of domestic artistic paper are required to be different, and the difference requirement of products is very large; accurate differentiation adjustment is difficult to achieve through the gluing mode.

3. Moisture-proof and mould-proof problem of painting and calligraphy paper

The writing and drawing paper is used as art paper and often records valuable artistic contents, but as a material mainly made of plant fibers, the writing and drawing paper has high moisture absorption and is easy to mildew, and particularly, the writing and drawing paper is relatively moist in the south, which can cause mildew and loss of art works.

Disclosure of Invention

In view of the problems or defects of the prior art, the invention aims to provide a hydrophobic enhanced painting and calligraphy paper and a preparation method thereof. The invention mainly utilizes the hydrophobic modified nano-cellulose to carry out surface sizing on the writing and painting paper, and solves the technical problems of the prior writing and painting paper.

In order to achieve the first object of the invention, the invention provides a hydrophobic reinforced painting and calligraphy paper, which comprises painting and calligraphy paper and a hydrophobic modified nano-cellulose coating formed on the surface of the painting and calligraphy paper.

Further, according to the technical scheme, the quantitative amount of the hydrophobic enhanced painting and calligraphy paper is 40-60g/m²。

Further, according to the technical scheme, the hydrophobically modified nano-cellulose is prepared by the following method, and the method comprises the following steps:

(1) crushing and uniformly stirring fiber slurry, then carrying out oxidation pretreatment on the fiber slurry by adopting a TEMPO (2,2,6, 6-tetramethylpiperidine oxide)/NaClO/NaBr system, and carrying out suction filtration and washing to obtain oxidized cellulose;

(2) preparing the oxidized cellulose obtained in the step (1) into a suspension with the concentration of 1-2%, and then carrying out high-pressure homogenization treatment to obtain a nano cellulose suspension;

(3) rotationally evaporating the nano-cellulose suspension obtained in the step (2) to obtain gel-like nano-cellulose; then adding N-N-dimethylformamide into the gel-like nano-cellulose according to the proportion, uniformly dispersing by ultrasonic, heating to 80-90 ℃, and stirring at constant temperature for 4-6 h; after stirring, continuously adding glutaric anhydride, propionic anhydride and 4-dimethylamino pyridine according to the proportion, and obtaining reaction liquid 1 after ultrasonic dispersion is uniform; heating the reaction solution 1 to 80-120 ℃ for constant-temperature reaction for 4-8h, cooling after the reaction is finished, centrifuging and washing a product to obtain esterified modified nano-cellulose;

(4) respectively adding a 1-tridecylamine solution and an n-decylamine solution into the esterified and modified nanocellulose obtained in the step (3) according to the ratio, uniformly mixing to obtain a reaction solution 2, adjusting the pH value of the reaction solution 2 to be neutral, and stirring at constant temperature of 40-80 ℃ for reaction for 2-6 hours; and after the reaction is finished, centrifuging and washing the product, and finally performing dialysis separation treatment to obtain the hydrophobic modified nano-cellulose.

Preferably, in the above technical solution, the fiber pulp in step (1) may be any one of wood pulp, cotton pulp, hemp pulp, bamboo pulp, reed pulp, and the like.

Preferably, in the above technical solution, the wood pulp is any one of hardwood pulp or softwood pulp.

Preferably, in the above technical scheme, the mass ratio of the oven-dried fiber, the 2,2,6, 6-tetramethylpiperidine oxide, the sodium bromide and the sodium hypochlorite in the fiber slurry in the step (1) is 1: 0.01-0.02: 0.05-0.2: 6-10.

Preferably, in the above technical solution, the pressure adopted in the high-pressure homogenization treatment in the step (2) is 800-1000 bar.

Preferably, in the above technical solution, the number of times of the high-pressure homogenization treatment in step (2) is 10-15, and the time for each treatment is 30-60 s.

Preferably, in the above technical solution, the stirring speed in step (3) is 400-800rpm, more preferably 500-600 rpm.

Preferably, in the above technical solution, the amount ratio of the oven-dried nanocellulose to N-dimethylformamide in the nanocellulose aqueous suspension in step (3) is 1-2 parts by mass: 60-100 parts by volume, wherein: the mass portion and the volume portion are as follows: ml is used as a reference.

Preferably, in the above technical solution, the mass ratio of the oven-dried nanocellulose to the glutaric anhydride, the propionic anhydride and the 4-dimethylaminopyridine in the nanocellulose aqueous suspension in the step (3) is 1: 20: 20: 0.6.

preferably, in the above technical scheme, the concentration of the 1-tridecylamine solution in the step (4) is 3-6%, and the specific preparation method of the 1-tridecylamine solution is as follows: adding 3-6g of 1-tridecylamine into 100mL of N-N Dimethylformamide (DMF), and uniformly stirring.

Preferably, in the above technical scheme, the concentration of the n-decylamine solution in the step (4) is 3-6%, and the specific preparation method of the n-decylamine solution is as follows: adding 3-6g of N-decylamine into 100mL of N-N Dimethylformamide (DMF), and uniformly stirring.

Preferably, in the above technical solution, the mass ratio of the esterified and modified nanocellulose in the step (4) to the 1-tridecylamine in the 1-tridecylamine solution to the n-decylamine in the n-decylamine solution is 1: 0.1-0.45: 0.1-0.45.

Preferably, in the above technical solution, the stirring speed in step (4) is 400-800rpm, more preferably 600 rpm.

The second purpose of the invention is to provide the preparation method of the hydrophobic reinforced painting and calligraphy paper, which is to prepare hydrophobic modified nano-cellulose into a sizing solution with the concentration of 2-8%, then coat the sizing solution on the surface of the painting and calligraphy paper, and put the painting and calligraphy paper into an oven for drying.

Further, according to the technical scheme, the mass ratio of the oven-dried fibers of the writing and drawing paper to the oven-dried hydrophobically modified nanocellulose is 1: 0.01-0.03.

Further, according to the technical scheme, the drying temperature is 80-90 ℃, and the drying time is 10-30 min.

Compared with the prior art, the hydrophobic enhanced painting and calligraphy paper and the preparation method thereof have the following beneficial effects:

(1) the nanocellulose modified by the two-step method is coated on the writing and painting paper in a surface sizing mode, and the nanocellulose is small in size, so that the nanocellulose is more easily deposited on the surface of the paper or permeates pores, the water vapor barrier property and the hydrophobicity of the paper can be enhanced, and therefore the nanocellulose is less prone to absorb moisture and mildew when the environmental humidity is high, and the storage time of the nanocellulose is prolonged.

(2) The invention controls the surface sizing of the writing and painting paper by controlling the process formula of the modified nano-cellulose, such as concentration, dosage, surface sizing speed and the like, thereby controlling different water absorbability and ink absorbability and further realizing differential adjustment.

(3) The modified nano-cellulose adopted by the invention is coated on the surface of the writing and painting paper, so that the strength performance of the writing and painting paper can be obviously improved, and meanwhile, the chemical components of the adopted modified nano-cellulose are the same as the plant fibers of the writing and painting paper, so that the writing of the writing and painting paper is not adversely affected.

(4) The nano-cellulose adopted in the invention is derived from plant fiber raw materials, and has the advantages of environmental protection, degradability and the like.

Drawings

FIG. 1 is a flow chart of the preparation process of the hydrophobic reinforced writing and painting paper of the invention.

Detailed Description

The present invention will be described in further detail below with reference to examples. The present invention is implemented on the premise of the technology of the present invention, and the detailed embodiments and specific procedures are given to illustrate the inventive aspects of the present invention, but the scope of the present invention is not limited to the following embodiments.

Various modifications to the precise description of the invention will be readily apparent to those skilled in the art from the information contained herein without departing from the spirit and scope of the appended claims. It is to be understood that the scope of the invention is not limited to the procedures, properties, or components defined, as these embodiments, as well as others described, are intended to be merely illustrative of particular aspects of the invention. Indeed, various modifications of the embodiments of the invention which are obvious to those skilled in the art or related fields are intended to be covered by the scope of the appended claims.

For a better understanding of the invention, and not as a limitation on the scope thereof, all numbers expressing quantities, percentages, and other numerical values used in this application are to be understood as being modified in all instances by the term "about". Accordingly, unless expressly indicated otherwise, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Firstly, oxidizing and pretreating cellulose by using 2,2,6, 6-tetramethylpiperidine oxide (TEMPO) to obtain cellulose with carboxyl, and then, carrying out high-pressure homogenization to obtain nano-cellulose; hydrophobic modification of the nano-cellulose is carried out by adopting a two-step method, and glutaric anhydride and propionic anhydride are used as composite anhydride as reagents for esterifying and modifying the nano-cellulose in the first step; and secondly, reacting 1-tridecylamine and n-decylamine with the esterified and modified nanocellulose through electrostatic adsorption to form a complex, hydrophobically modifying the nanocellulose, and finally coating the water-modified nanocellulose on the surface of the raw paper for painting and calligraphy, and drying.

Two key properties of the writing and drawing papers developed in this invention are water resistance and physical strength properties (tear index, length at break, etc.). The higher the concentration of the modified nanocellulose is, the better the hydrophobicity of the paper is, the water absorption is deteriorated, while the addition of the modified nanocellulose slightly improves the physical strength property, but also needs to consider the influence of the cost and the physical strength of the paper, so that it is necessary to select an appropriate concentration for surface sizing. The method firstly uses 2,2,6, 6-tetramethyl piperidine oxide (TEMPO) to oxidize and pretreat the cellulose, and then carries out high-pressure homogenization, the dispersion performance of the prepared nano cellulose in water is greatly improved, and the generated carboxyl has negative charges and has charge repulsion, thereby improving the dispersion performance.

According to the invention, glutaric anhydride and propionic anhydride are used as the composite anhydride as the reagent of the esterification modified nano-cellulose to carry out esterification reaction with the prepared nano-cellulose, so that the hydrophobicity is obviously improved.

The 1-tridecylamine and the n-decylamine of the invention react with the esterified nano-cellulose through electrostatic adsorption to form a complex, so that the hydrophobicity is further improved.

The concentration of each reagent of the present invention refers to the mass/volume percent concentration of the dispersoid and the dispersion medium in g/mL.