CN109403136B - Composite coating for improving mechanical property of paper and preparation method thereof - Google Patents
Composite coating for improving mechanical property of paper and preparation method thereof Download PDFInfo
- Publication number
- CN109403136B CN109403136B CN201811295872.XA CN201811295872A CN109403136B CN 109403136 B CN109403136 B CN 109403136B CN 201811295872 A CN201811295872 A CN 201811295872A CN 109403136 B CN109403136 B CN 109403136B
- Authority
- CN
- China
- Prior art keywords
- paper
- nano
- polyvinyl alcohol
- sodium lignosulfonate
- composite coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H19/00—Coated paper; Coating material
- D21H19/10—Coatings without pigments
- D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
- D21H19/20—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H19/00—Coated paper; Coating material
- D21H19/10—Coatings without pigments
- D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
Abstract
The invention discloses a composite coating for improving the mechanical property of paper and a preparation method thereof. Every 100 parts of water comprises the following components in parts by mass: 5-15 parts of polyvinyl alcohol, 0.05-1.5 parts of nano microfibril and 0.05-2.25 parts of sodium lignosulfonate. Adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution; dispersing the mixed solution in an ultrasonic cleaner for 10-20 minutes to obtain a dispersed nano microfibril solution; adding polyvinyl alcohol into the nano microfibril solution, and fully dissolving the polyvinyl alcohol at 90-95 ℃ to prepare a composite reagent; and dispersing the composite reagent in an ultrasonic cleaner for 10-20 minutes, standing and defoaming to obtain the composite coating. The invention can improve the dispersibility of the composite coating on paper and greatly improve the mechanical property of the paper.
Description
Technical Field
The invention relates to a composite coating for improving the mechanical property of paper and a preparation method thereof, belonging to the field of paper manufacture.
Background
With the rapid development of social economy and scientific technology, the application requirements of paper are becoming more and more strict, the coated paper is formed by coating a coating material containing a pigment as a main component on at least one surface of base paper and then drying the base paper, and the coated paper can be widely applied to daily work and life as commercial printed matters such as posters, brochures, posters and the like or publications such as books, magazines and the like after multicolor printing or single-color printing, so that the demand of the coated paper is increasing. With the continuous improvement of the quality of the coated paper, higher requirements are put forward on the application of the papermaking coating. Among these, the mechanical properties of paper are important indicators for the durability of paper, and the mechanical properties of paper affect the properties of coated paper. The coating applied in the prior coated paper has the problems of poor dispersibility, and can not provide good mechanical properties for the coated paper, thus causing low mechanical strength of the paper.
Disclosure of Invention
The invention aims to provide a composite coating for improving the mechanical property of paper and a preparation method thereof. The invention can improve the dispersibility of the composite coating on paper and greatly improve the mechanical property of the paper.
The technical scheme of the invention is as follows: a composite coating for improving the mechanical property of paper comprises the following components in 100 parts by mass of water: 5-15 parts of polyvinyl alcohol, 0.05-1.5 parts of nano microfibril and 0.05-2.25 parts of sodium lignosulfonate.
The composite coating for improving the mechanical property of paper comprises the following components in 100 parts by mass of water: 8-12 parts of polyvinyl alcohol, 0.08-1.2 parts of nano microfibril and 0.1-1.8 parts of sodium lignosulfonate.
The composite coating for improving the mechanical property of paper comprises the following components in 100 parts by mass of water: 10 parts of polyvinyl alcohol, 0.8 part of nano microfibril and 1.5 parts of sodium lignosulfonate.
The preparation method of the composite coating for improving the mechanical property of the paper comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. placing the mixed solution into an ultrasonic cleaner, and dispersing for 10-20 minutes at 20-30 kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol into the nano microfibril solution, and fully dissolving the polyvinyl alcohol at 85-95 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner, dispersing for 10-20 minutes at 20-30 kHz, standing and defoaming to obtain a finished product.
The preparation method of the composite coating for improving the mechanical property of the paper comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 15 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol at 90 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner to disperse for 15 minutes at 25kHz, and standing and defoaming to obtain a finished product.
In the step c, the polyvinyl alcohol is polyvinyl alcohol solid particles which absorb water and swell at 55-65 ℃.
In the preparation method of the composite coating for improving the mechanical properties of the paper, in the step c, the polyvinyl alcohol is dissolved in a constant-temperature water bath.
Compared with the prior art, the composite coating is prepared by adopting the preferable components and proportion, on one hand, the hydroxyl on the sodium lignosulfonate and the nano microfibril colloid generate hydrogen bonds by adding the sodium lignosulfonate, so that moisture is generated in the nano microfibril colloid, the composite coating is favorably prepared, the effect of improving the dispersibility of the composite coating is achieved, and the dispersibility of the composite coating after being coated is greatly improved. On the other hand, the polyvinyl alcohol and the nano microfibrils are used as main components of the composite coating, the molecules of the nano microfibrils are combined with paper fibers, and sodium lignosulfonate is added to be combined with hydroxyl groups on the nano microfibrils, so that the molecules of the nano microfibrils are connected, the molecules of the nano microfibrils are more compact, the acting force is stronger, the binding force between the paper fibers is enhanced, and the mechanical properties such as the tensile strength, the folding resistance and the tearing strength of the paper are greatly enhanced. In addition, the polyvinyl alcohol is preferably solid particles of polyvinyl alcohol which absorbs water and swells at the temperature of between 55 and 65 ℃, so that the dissolution can be accelerated. Because the surface of the conventional paper-plastic packaging material is usually covered with a plastic film to enhance the tearing resistance and the like, but the conventional paper-plastic packaging material is difficult to degrade in nature and easy to cause environmental pollution, and when the conventional paper-plastic packaging material is in direct contact with food, the pollutants remained in the conventional paper-plastic packaging material can migrate to the food through the processes of absorption, dissolution, diffusion and the like, so that the conventional paper-plastic packaging material causes certain harm to human health and the environment. Therefore, the invention adopts the polyvinyl alcohol and the nano microfibril with good environmental protection and degradability as the raw materials of the composite coating, can achieve the mechanical property of the conventional paper-plastic packaging material which adopts a plastic film for covering, has the advantage of environmental protection, and protects the environment.
Description of the drawings:
FIG. 1: the invention is a dispersion comparison graph of the composite coating under different sodium lignosulfonate adding amounts;
FIG. 2: the invention is a line graph of the tensile strength of paper under different sodium lignosulfonate addition amounts;
FIG. 3: the invention is a comparison graph of the tensile strength of paper under different nano microfibril addition amounts;
FIG. 4: the invention relates to a folding line graph of the folding endurance of paper under different sodium lignosulfonate addition amounts;
FIG. 5: according to the invention, the folding endurance contrast chart of the paper is obtained under different nano microfibril addition amounts;
FIG. 6: the invention has a line graph of paper tearing strength under different sodium lignosulfonate adding amounts;
FIG. 7: the invention is a graph comparing the tear of paper at different levels of nano-microfibril addition.
Detailed Description
The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.
Example 1: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight:
10g of polyvinyl alcohol, 0.8g of nano microfibril, 0.1g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 10 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 85 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner, dispersing for 10-14 minutes at 25kHz, standing and defoaming to obtain the composite coating.
Example 2: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight: 10g of polyvinyl alcohol, 0.8g of nano microfibril, 0.3g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 13 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 87 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner to disperse for 13 minutes at 25kHz, and standing and defoaming to obtain the composite coating.
Example 3: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight: 10g of polyvinyl alcohol, 0.8g of nano microfibril, 0.5g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 16 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 89 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner to disperse for 16 minutes at 25kHz, standing and defoaming to obtain the composite coating.
Example 4: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight:
10g of polyvinyl alcohol, 0.8g of nano microfibril, 1g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 18 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 92 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner, dispersing for 18 minutes at 25kHz, standing and defoaming to obtain the composite coating.
Example 5: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight:
10g of polyvinyl alcohol, 0.8g of nano microfibril, 1.5g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 15 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 90 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner, dispersing for 15 minutes at 25kHz, standing and defoaming to obtain the composite coating.
Example 6: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight:
10g of polyvinyl alcohol, 0.8g of nano microfibril, 2g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 20 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 95 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner, dispersing for 20 minutes at 25kHz, standing and defoaming to obtain the composite coating.
Example 7: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight:
5g of polyvinyl alcohol, 0.5g of nano microfibril, 1g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. placing the mixed solution into an ultrasonic cleaner to disperse for 15 minutes at 20kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 85 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner, dispersing for 18 minutes at 25kHz, standing and defoaming to obtain the composite coating.
Example 8: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight:
14g of polyvinyl alcohol, 1.3g of nano microfibril, 1.85g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. placing the mixed solution into an ultrasonic cleaner to be dispersed for 10 minutes at 30kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 90 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner to disperse for 13 minutes at 25kHz, and standing and defoaming to obtain the composite coating.
Example 9: a composite coating for improving the mechanical property of paper comprises the following components in parts by weight:
12g of polyvinyl alcohol, 0.5g of nano microfibril, 1.4g of sodium lignosulfonate and 100g of water.
The preparation method of the composite coating comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 20 minutes at 25kHz to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol which absorbs water and swells at the temperature of 60 ℃ into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol in a constant-temperature water bath kettle at the temperature of 95 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent into an ultrasonic cleaner, dispersing for 19 minutes at 25kHz, standing and defoaming to obtain the composite coating.
Comparative example 1: the preparation and preparation of the composite coating were carried out according to the procedure of example 1, but sodium lignosulfonate was not added to the raw materials, to prepare a composite coating without sodium lignosulfonate.
The composite coatings of examples 1 to 6 and the comparative example were applied to a coating experiment using a 2AA 2300 hand coater, Jie Ener zehntner Switzerland, the paper used in the experiment was from New materials Ltd, Zhejiang blue, and the basis weight of the paper was 60g/m2The polyvinyl alcohol used is industrial grade 1799, and the solid content of the nano microfibrils is 1.1%. In the coating experiment, the surface treatment of the composite coating is carried out on the paper in a manual rod coating mode, only one-way coating is carried out in the coating process, the coated paper is dried in an oven at 50 ℃ for 20min, and then the paper is placed in a constant temperature and humidity test box (relative humidity: 50%; temperature: 25 ℃) for 24h and then the dispersion of the composite coating is observed, and the result is shown in the attached figure 1. As can be seen from fig. 1, when the polyvinyl alcohol concentration (concentrations described herein are all mass percent concentrations) is 10%, i.e., 10 parts by weight of polyvinyl alcohol are included in 100 parts by weight of water, and the concentration of the nano microfibrils is 0.8%, namely, 100 parts of water comprises 0.8 part of nano microfibril by weight, small particles on the coated paper gradually decrease with the increase of the addition amount of the sodium lignosulfonate, the concentration of the sodium lignosulfonate in example 1 is 0.1 percent, namely, 100 parts by weight of the composition comprises 0.1 part of sodium lignin sulfonate, the concentration of the sodium lignin sulfonate in example 2 is 0.3 percent, the concentration of the sodium lignin sulfonate in example 3 is 0.5 percent, the concentration of the sodium lignin sulfonate in example 5 is 1.5 percent, the comparative example does not contain sodium lignosulfonate, and it can be seen from the examples and the comparative example that the dispersibility of the polyvinyl alcohol and the nano microfibrils in the solution is better and better as the addition amount of the sodium lignosulfonate is increased. The main reason is that the dissolution of polyvinyl alcohol and nano microfibrils is carried out under aqueous conditions, and the nano microfibrils can be dissolved only in water. When the concentration ratio of the two components in the composite coating material is too high, the amount of water added is insufficient for dissolution of the nano-microfibrils, and the nano-microfibrils in the form of particles appear. When sodium lignosulfonate is added, the hydroxyl on the sodium lignosulfonate and the nano microfibril colloid generate hydrogen bonds, so that moisture is generated in the nano microfibrils, the preparation of the composite coating is facilitated, and the effect of improving the dispersibility of the composite coating is achieved.
After the dispersibility test of the paper coated with the composite coating, the paper was coated with the composite coating prepared in examples 1 to 6, and during the coating process, only one-way coating was performed, and the coated paper was dried in an oven at 50 ℃ for 20min, and then placed in a constant temperature and humidity test chamber (relative humidity: 50%, temperature: 25 ℃) for 24 hours, and then the paper was tested for mechanical properties of tensile strength, folding resistance and tearing strength.
1. The papers coated with the composite coatings obtained in examples 1 to 6 and the comparative example were tested for tensile strength and the tensile strength of the papers was analyzed by using a KSM-bx5450ST biaxial stretching machine. The detection conditions are as follows: the coated paper had a width of 40mm, a length of 100mm, a thickness of 0.14mm, and a slider weight of 10N. The final test results are shown in FIG. 2. As shown in FIG. 2, when the concentration of sodium lignosulfonate exceeds 0.3%, the increase in the concentration of sodium lignosulfonate has an obvious effect on the increase in tensile strength. The tensile strength was the lowest at a concentration of 0.1% sodium lignosulfonate, 45.97 Mpa. The tensile strength of the paper is increased along with the increase of the concentration of the sodium lignosulfonate, the corresponding tensile stress of the sodium lignosulfonate with the concentration of 0.5% is increased by more than 45-50% compared with the tensile stress of the paper with the concentration of 0.1%, the tensile strength of the paper is obviously enhanced, and the enhancement amplitude of the tensile strength of the paper gradually tends to be smooth when the concentration of the sodium lignosulfonate reaches 1% -1.5%. At the stage when the sodium lignosulfonate concentration reaches 1.5% -2%, the tensile strength of the paper is reduced. This is because sodium lignosulfonate dissolves in water and causes ionization, and the degree of ionization is large, forming a large anion and a small cation of the same amount of heterogeneous charge. The positive and negative ions are firmly adsorbed on the surface of the nano-microfibrils, so that the nano-microfibrils have the same charge. The oppositely charged ions are free to diffuse into the surrounding liquid medium, forming a diffusion layer of charged ions (i.e., an electrical double layer). Because ions with the same charge repel each other to form electrostatic repulsion, the nano microfibrils are prevented from flocculating in an aqueous medium, so that the aim of uniform dispersion is fulfilled, after the paper is coated with the composite coating, nano microfibril molecules are combined with paper fibers, and the added sodium lignosulfonate is combined with hydroxyl on the nano microfibrils along with the increase of the addition amount of the sodium lignosulfonate, so that the nano microfibril molecules are connected, the fiber binding force is enhanced, and the tensile strength of the paper is improved. However, when the amount of sodium lignosulfonate added is too large, the formed electric double layer is destroyed, charge imbalance distribution is caused, and nano microfibrils are unevenly dispersed, thereby reducing the mechanical properties of the paper.
The same procedure was followed for the preparation of composite coatings for paper by adjusting the number of nano-microfibrils in examples 1-6 from 0.8 to 1 and 0.2, i.e., the concentration of nano-microfibrils was adjusted from 0.8% to 1% and 0.2%, respectively, and the tensile strength of the paper was measured using a KSM-bx5450ST biaxial tensile tester. The detection conditions are as follows: the coated paper had a width of 40mm, a length of 100mm, a thickness of 0.14mm, and a slider weight of 10N. The final test results are compared to the paper tensile strength with 8% concentration of nanofibrils, and the results are shown in figure 3. As can be seen from fig. 3, when the concentrations of the nano-microfibrils are 0.8% and 1%, the tensile strength of the paper is much greater than that of the nano-microfibrils with the concentration of 0.2%, which indicates that the increase of the content of the nano-microfibrils has a significant improvement on the tensile strength of the paper. However, the fact that the tensile strength of the paper is better at a concentration of 8% than at a concentration of 10% is due to the fact that the dispersion of the coating is directly affected by the amount of nanofibrils added at different concentrations, given the same concentration of polyvinyl alcohol and sodium lignosulfonate. The nano-microfibrils with the concentration of more than 0.8% can generate self-aggregation phenomenon, so that the nano-microfibrils can not play a role in reinforcing fiber binding force, and the tensile strength of the coated paper is the best when the nano-microfibrils are at the concentration of 0.8%, and the nano-microfibrils are reduced after the concentration of more than 0.8%.
2. The paper folding strength of the paper coated with the composite coatings prepared in examples 1-6 and the comparative example was measured. The folding endurance of the paper is analyzed by a DCP-MIT135 computer controlled folding endurance instrument. The detection conditions are as follows: the test pressure was 9.8N. The results are shown in FIG. 4. As can be seen from fig. 4, the folding endurance decreased first and then increased as the amount of sodium lignosulfonate added increased. The folding endurance was 3.18 at 0.1% sodium lignosulfonate and decreased to a minimum of 3.12 at 0.3%, and then the increase in folding endurance of the paper gradually leveled off as sodium lignosulfonate was added at a stage when the concentration of sodium lignosulfonate reached 1% to 1.5%. When the concentration of the sodium lignosulfonate reaches 1.5% -2%, the folding endurance of the paper is reduced. It can be seen that the folding endurance of the paper should show an increasing trend as long as the sodium lignosulfonate is within a reasonable addition range. The reason is that the sulfonic acid group is contained in the sodium lignosulfonate, so that the excessive sulfonic acid group on the surface of the nano microfibril leads to relatively reduced combination with the fiber, thereby causing adverse effect on the paper performance, and the folding endurance of the coated paper is reduced along with the addition of the sodium lignosulfonate. However, with the addition of sodium lignosulfonate, the influence of sodium lignosulfonate on the nano microfibrils becomes smaller and smaller, and meanwhile, with the increase of the addition amount of sodium lignosulfonate, the added sodium lignosulfonate is combined with hydroxyl groups on the nano microfibrils to link the molecules of the nano microfibrils, so that the molecules of the nano microfibrils are tighter, the acting force is stronger, the binding force between paper fibers is enhanced, and the folding resistance of the coated paper is improved.
The same procedure was followed for the same steps as in examples 1 to 6, except that the number of nano-microfibrils in examples 1 to 6 was changed from 0.8 to 1 or 0.2, i.e., the concentration of nano-microfibrils was changed from 0.8% to 1% or 0.2%, and the prepared composite coating was applied to paper and then tested for paper folding strength. The folding endurance of the paper is analyzed by a DCP-MIT135 computer controlled folding endurance instrument. The detection conditions are as follows: the test pressure was 9.8N. The final test results are shown in FIG. 5, comparing the paper folding strength with that of 0.8% concentration of nano-microfibrils. As can be seen from fig. 5, after the paper is coated with the composite coating prepared from the nano-microfibrils with the concentrations of 0.8% and 1%, the folding endurance of the paper is consistent in the general trend, and with the increase of sodium lignosulfonate, the folding endurance is in a concave parabolic shape, and the folding endurance is much greater than that of the paper with the nano-microfibrils with the concentration of 0.2%, which indicates that the increase of the content of the nano-microfibrils has a significant improvement on the tensile strength of the paper. When the concentration of the sodium lignosulfonate reaches 10% -15%, the folding endurance of the paper gradually tends to be smooth. However, the test results for the addition of 0.8% of nanofibrils are slightly better than 1%. This is because the folding endurance of paper is mainly affected by the strength, flexibility, fiber length and bonding strength of the fibers themselves. Under the condition that the concentration of the polyvinyl alcohol and the sodium lignosulfonate is constant, the bonding force of the paper fibers is further improved along with the gradual increase of the addition amount of the nano microfibrils, but the nano microfibrils have a tendency of decreasing after the concentration is more than 0.8 percent.
3. Paper tear was measured on the papers coated with the composite coatings obtained in examples 1 to 6 and comparative example. The tear of the paper was analyzed using a J-SLY1000 paper tear Meter. The results are shown in FIG. 6. As can be seen from fig. 6, the tendency of the tear strength and the folding endurance of the paper sheet are consistent. The addition amount of sodium lignosulfonate in a proper range can greatly improve the mechanical properties. With the increase of the sodium lignosulfonate, the mechanical property of the paper tends to decrease first and then increase. When the addition amount of sodium lignin sulfonate is 0.3%, the tearing strength and the folding strength of the coated paper are the minimum values in the test range, and after exceeding 0.3%, the addition amount of sodium lignin sulfonate has a remarkable effect on the enhancement of the tearing strength. Then, with the addition of the sodium lignosulfonate, the tearing strength enhancing amplitude of the paper gradually flattens when the concentration of the sodium lignosulfonate reaches 1 to 1.5 percent. At the stage when sodium lignosulfonate reaches 1.5% -2%, the tear of the paper is reduced. The reason is that after the sodium lignosulfonate is added, the hydroxyl on the surface of the nano microfibril molecules and the sodium lignosulfonate molecules can generate transverse hydrogen bonds, so that the bonding force among fibers is weakened, and the tearing strength of the coated paper is reduced. After the sodium lignosulfonate is added to a certain amount, the tearing strength of the coated paper tends to increase, because the sodium lignosulfonate has smaller and smaller influence on the nano microfibrils, and meanwhile, the added sodium lignosulfonate is combined with hydroxyl groups on the nano microfibrils along with the increase of the addition amount of the sodium lignosulfonate, so that the nano microfibril molecules are connected, the nano microfibril molecules are tighter, the acting force is stronger, the influence of the sodium lignosulfonate on the bonding force between the fibers tends to be in a positive state, the bonding force between the paper fibers is enhanced, and the tearing resistance of the coated paper also tends to be improved. However, when the amount of sodium lignosulfonate added is too large, the formed electric double layer is destroyed, charge imbalance distribution is caused, and nano microfibrils are unevenly dispersed, thereby reducing the mechanical properties of the paper.
The same procedure was followed to adjust the number of nano-microfibrils in examples 1-6 from 0.8 to 1 or 0.2, i.e., the concentration of nano-microfibrils was changed from 0.8% to 1% or 0.2%, and the obtained composite coating was applied to paper and then tested for paper tear, which was analyzed using a J-SLY1000 paper tear tester. The final test results are compared to the paper tear at a concentration of 0.8% nanofibrils as shown in figure 7. As can be seen from the attached FIG. 7, the tear strength of the paper coated with the composite coating prepared from 0.8% nano-microfibrils and 1% nano-microfibrils is consistent in the general trend, the tear strength shows a concave parabola shape with the increase of sodium lignosulfonate, and the tear strength of the paper coated with the composite coating is far greater than that of the paper coated with the nano-microfibrils in the concentration of 0.2%, which indicates that the addition amount of the nano-microfibrils is still obviously improved for the tear strength of the paper. When the concentration of the sodium lignosulfonate reaches 1% -1.5%, the tearing strength of the paper gradually tends to be flat. But the test results from the concentration of 8% nano-microfibrils are slightly better than 1%. The tear ability of paper is mainly affected by the strength, flexibility, fiber length and bonding strength of the fibers themselves. Under the condition that the concentration of polyvinyl alcohol and sodium lignosulfonate is certain, the addition amount of the nano microfibrils is gradually increased, so that the binding force of paper fibers is further improved, but the nano microfibrils can generate self-aggregation phenomenon when the concentration of the nano microfibrils is more than 0.8%, so that the nano microfibrils cannot play a role in enhancing the binding force of the fibers, and the folding resistance and the tearing strength of the paper are reduced on the contrary after the concentration of the nano microfibrils is more than 0.8%.
In summary, in the invention, on one hand, by adding sodium lignosulfonate, hydroxyl groups on the sodium lignosulfonate and the nano microfibril colloid generate hydrogen bonds, so that moisture is generated in the nano microfibril colloid, thereby facilitating the preparation of the composite coating, simultaneously achieving the effect of improving the dispersibility of the composite coating, and greatly improving the dispersibility of the composite coating after coating. On the other hand, the polyvinyl alcohol and the nano microfibrils are used as the composite coating, the molecules of the nano microfibrils are combined with paper fibers, sodium lignosulfonate (5-20%) is added in a reasonable range, and the sodium lignosulfonate is combined with hydroxyl on the nano microfibrils to enable the molecules of the nano microfibrils to be connected, so that the molecules of the nano microfibrils are more compact and the acting force is stronger, the binding force between the paper fibers is enhanced, and the mechanical properties such as the tensile strength, the folding strength and the tearing strength of the paper are greatly enhanced. Experiments show that the composite coating most preferably comprises 10 parts by weight of polyvinyl alcohol, 0.8 part by weight of nano microfibril and 1.5 parts by weight of sodium lignosulfonate in 100 parts by weight, and the composite coating prepared from the components and the ratio has the optimal paper mechanical property.
Claims (5)
1. The composite coating for improving the mechanical property of paper is characterized in that: every 100 parts of water comprises the following components in parts by mass: 8-12 parts of polyvinyl alcohol, 0.08-1.2 parts of nano microfibril and 0.1-1.8 parts of sodium lignosulfonate;
the preparation method of the composite coating for improving the mechanical property of paper comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. dispersing the mixed solution in an ultrasonic cleaner for 10-20 minutes to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol into the nano microfibril solution, and fully dissolving the polyvinyl alcohol at 85-95 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent under an ultrasonic cleaner for dispersing for 10-20 minutes, and standing and defoaming to obtain a finished product.
2. The composite coating for improving the mechanical property of paper, according to claim 1, is characterized in that: every 100 parts of water comprises the following components in parts by mass: 10 parts of polyvinyl alcohol, 0.8 part of nano microfibril and 1.5 parts of sodium lignosulfonate.
3. The preparation method of the composite coating for improving the mechanical property of paper, according to claim 1, is characterized in that: the method comprises the following steps:
a. adding the nano microfibril, sodium lignosulfonate and water into a container in proportion, and fully and uniformly stirring to obtain a mixed solution;
b. placing the mixed solution under an ultrasonic cleaner for dispersing for 15 minutes to obtain a dispersed nano microfibril solution;
c. adding polyvinyl alcohol into the nano microfibril solution, and then fully dissolving the polyvinyl alcohol at 90 ℃ to prepare a composite reagent;
d. and (3) placing the composite reagent in an ultrasonic cleaner for dispersing for 15 minutes, and standing and defoaming to obtain a finished product.
4. The preparation method of the composite coating for improving the mechanical property of paper, according to claim 3, is characterized in that: in the step c, the polyvinyl alcohol is polyvinyl alcohol solid particles which absorb water and swell at the temperature of 55-65 ℃.
5. The preparation method of the composite coating for improving the mechanical property of paper, according to claim 3, is characterized in that: in step c, the polyvinyl alcohol is dissolved in a constant temperature water bath.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811295872.XA CN109403136B (en) | 2018-11-01 | 2018-11-01 | Composite coating for improving mechanical property of paper and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811295872.XA CN109403136B (en) | 2018-11-01 | 2018-11-01 | Composite coating for improving mechanical property of paper and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109403136A CN109403136A (en) | 2019-03-01 |
| CN109403136B true CN109403136B (en) | 2021-05-18 |
Family
ID=65471047
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811295872.XA Active CN109403136B (en) | 2018-11-01 | 2018-11-01 | Composite coating for improving mechanical property of paper and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109403136B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101823358A (en) * | 2010-03-29 | 2010-09-08 | 南京林业大学 | Method for enhancing paperless membrane-coated artificial board by micro/nano fibril |
| CN102057105A (en) * | 2008-04-03 | 2011-05-11 | 英文蒂亚有限责任公司 | Composition for coating of printing paper |
| CN106833139A (en) * | 2016-12-24 | 2017-06-13 | 胡云 | A kind of preparation of cellulose nano-fibrous base oil fat barrier coat and its application process |
| WO2017199252A1 (en) * | 2016-05-16 | 2017-11-23 | Yissum Research Development Company Of The Hebrew University Of Jerusalem Ltd | Modified nanocrystaline cellulose materials and formulations and products made therefrom |
-
2018
- 2018-11-01 CN CN201811295872.XA patent/CN109403136B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102057105A (en) * | 2008-04-03 | 2011-05-11 | 英文蒂亚有限责任公司 | Composition for coating of printing paper |
| CN101823358A (en) * | 2010-03-29 | 2010-09-08 | 南京林业大学 | Method for enhancing paperless membrane-coated artificial board by micro/nano fibril |
| WO2017199252A1 (en) * | 2016-05-16 | 2017-11-23 | Yissum Research Development Company Of The Hebrew University Of Jerusalem Ltd | Modified nanocrystaline cellulose materials and formulations and products made therefrom |
| CN106833139A (en) * | 2016-12-24 | 2017-06-13 | 胡云 | A kind of preparation of cellulose nano-fibrous base oil fat barrier coat and its application process |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109403136A (en) | 2019-03-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| FI124464B (en) | Process for the preparation of pulp slurry, pulp slurry and paper | |
| Yan et al. | Improvement of paper strength with starch modified clay | |
| US9845405B2 (en) | Coating composition of nano cellulose, its uses and a method for its manufacture | |
| TW413705B (en) | Chitosan-coated pulp, a paper using the pulp, and a process for making them | |
| Honorato et al. | Transparent nanocellulose-pigment composite films | |
| SE0950819A1 (en) | A coated substrate, a process for producing a coated substrate, a package and a dispersion coating | |
| CN1942629A (en) | Aramid paper blend | |
| US11414817B2 (en) | Aramid paper coated with aramid nanofibers and a method of preparing the same | |
| Li et al. | Surface modification of cellulose fibers with layer-by-layer self-assembly of lignosulfonate and polyelectrolyte: effects on fibers wetting properties and paper strength | |
| Ma et al. | Self-reinforced grease-resistant sheets produced by paper treatment with zinc chloride solution | |
| CN112342839A (en) | Trace coating food packaging paper and preparation method thereof | |
| Nassar et al. | Novel coating of bagasse paper sheets by gelatin and chitosan | |
| Awada et al. | The development of a composite based on cellulose fibres and polyvinyl alcohol in the presence of boric acid | |
| CN114150533A (en) | Super-hydrophobic heat-resistant paper base material and preparation method thereof | |
| CN106801363A (en) | A kind of compound degradable waterproof paper of PLA enhanced film waterproof heat resistant performance | |
| CN109403136B (en) | Composite coating for improving mechanical property of paper and preparation method thereof | |
| Hollertz et al. | Novel cellulose nanomaterials | |
| Huang et al. | Distribution analysis of cellulose nanofibrils in paper handsheets: Dye-labeled Method | |
| CN115992464A (en) | Surface sizing agent for low gram weight fine dried noodle cardboard paper and processing method thereof | |
| Jo et al. | Multi-layer barrier coating technology using nano-fibrillated cellulose and a hydrophobic coating agent | |
| CN108691239B (en) | Preparation method and application of composite modified corn starch flame-retardant material | |
| JP5254831B2 (en) | Method for producing cast-coated paper and cast-coated paper produced by this production method | |
| CN113677850B (en) | Fiber composition, use of said composition and articles comprising said composition | |
| CN114541170A (en) | Coating composition for papermaking, gravure light coated paper and manufacturing method thereof | |
| CN106801361A (en) | A kind of pyrolkigneous liquid cooperates with the enhanced environment-friendly degradable waterproof paper of lanthanum zinc white carbon black antibacterial |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |