CN104452425B - Microfiber cellulose enveloped and retained high filling papermaking process - Google Patents

Abstract

The invention discloses a papermaking process of microfibrillated cellulose enveloping to aid retention and high filling. The industrial microfibrillated cellulose is treated with ultrasonic wave and then disintegrated by PFI mill to improve its fibrillation degree. Then it is mixed with filler carbonic acid Calcium or talcum powder dispersion is mixed evenly, and after standing still, filler/MFC pre-enveloping body is formed, then cationic polyacrylamide is added to form a relatively stable enveloping body, and then added to papermaking slurry and mixed evenly, and finally ordinary Papermaking by paper forming process can obtain highly filled paper. Microfibrillated cellulose has a high degree of branching, and can form a fine network structure with a number much larger than that of ordinary pulp fibers by overlapping each other during papermaking wet forming, which is conducive to the retention and envelopment of filler particles, and significantly improves the retention of fillers in paper. The specific surface area of microfibrillated cellulose is extremely large, and the free hydroxyl groups on the surface are extremely rich, which can form hydrogen bonds several times that of ordinary cellulose fibers, which solves the problem of poor strength of high-filler paper-based materials.

Description

A Microfibrillated Cellulose Encapsulation Aids Retention and High Filling Papermaking Process

【Technical field】

The invention belongs to the field of pulping and papermaking, and in particular relates to a papermaking process.

【Background technique】

Increasing the content of fillers in paper is not only beneficial to reduce the production cost of paper, improve corporate profits, but also help to alleviate the shortage of fiber raw material resources in the paper industry. However, the filler is usually an inorganic mineral powder, which cannot produce chemical bonds or hydrogen bonds between the particles or between the fibers; at the same time, the presence of the filler particles will hinder the hydrogen bond between the pulp fibers through the steric effect. Fillers will cause the loss of paper strength, including paper physical strength and surface strength, and the higher the filler content, the greater the strength loss. The low physical strength of the paper can easily cause the paper to be easily broken and damaged during production and application; the reduced surface strength can easily cause the paper to lint and powder, which is difficult to meet the needs of modern high-speed printing. Therefore, how to increase the filler content of paper and protect the strength of paper is a technical problem in front of paper-making technicians. At the same time, during the forming process of paper with high filler content, the retention rate of filler is low, and the loss with white water is large. How to improve the high retention of filler is another technical problem to realize high filling of paper.

【Content of invention】

The purpose of the present invention is to provide a microfibrillated cellulose enveloping aid retention and high filling papermaking process, which improves the strength of paper and realizes the coexistence of high filling and high strength of paper.

To achieve the above object, the technical solution adopted in the present invention is:

A kind of microfibrillated cellulose enveloping aid retention high filling papermaking process, comprises the following steps:

1) First, dilute the industrial microfibrillated cellulose product with water to a concentration of 1% to 5% by mass, and then perform ultrasonic treatment at room temperature;

2) concentrating the microfibrillated cellulose after the ultrasonic treatment in step 1) to a concentration of 10% by mass, and performing fine fiberization treatment with a PFI refiner;

3) Dilute the microfibrillated cellulose after the fibrillation treatment in step 2) with water to a concentration of 2% to 8% by mass, and then add fillers; after mixing uniformly under high shear force, let stand to form fillers/MFC pre- Envelope dispersion system; wherein, the filler accounts for 70% to 90% of the total solids in the filler/MFC pre-envelope dispersion system;

4) Add the retention and drainage aid cationic polyacrylamide according to the solid matter percentage of 0.02% to 0.06% in the filler/MFC pre-envelope dispersion system, and form the filler/MFC inclusion body dispersion system after low-shear mixing. ;

5) Add the filler/MFC inclusion body dispersion system formed in step 4) to the chemical pulp and carry out low-shear force mixing to form a total dispersion system; wherein, the solid content in the filler/MFC inclusion body dispersion system is the total 45% to 70% of the total mass of solids in the dispersion system; then quickly put into a paper sheet forming machine for sheet forming and drying to obtain highly filled paper with microfibrillated cellulose enveloping and retaining aid.

Preferably, the parameters of the ultrasonic treatment in step 1) are: ultrasonic power 300W, frequency 20kHz, treatment time 20-40min.

Preferably, in step 2), the processing rotation number of the PFI refiner is controlled to be 20000-60000 rotations.

Preferably, in step 3), the mixture is uniformly mixed under high shear force and then left to stand for 1-5 seconds to form a filler/MFC pre-envelope dispersion system.

Preferably, the filler added in step 3) is light calcium carbonate or talcum powder.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, microfibrillated cellulose is used as retention and strengthening means. The microscopic structure of microfibrillated cellulose is dendritic, with a high degree of branching. During papermaking wet forming, the number of overlapping fibers can be much larger than that of ordinary pulp fibers. The fine network structure can form an effective trapping and enveloping of filler particles, significantly improving the retention rate of fillers in paper. At the same time, the specific surface area of microfibrillated cellulose on the surface of the envelope is extremely large, and the free hydroxyl groups on the surface are extremely rich, which can form hydrogen bonds with each other and with fibers several times that of ordinary pulp fibers, which solves the problem of poor strength of paper with high filler content. The problem. Finally, the contradiction between paper strength and high filling amount in the high filling technology is better resolved.

【detailed description】

The invention discloses a microfibrillated cellulose enveloping retention aid high filling papermaking process, comprising the following steps:

1) First, dilute the industrial microfibrillated cellulose product with water to a concentration of 1% to 5% by mass, and then perform ultrasonic treatment at room temperature with an ultrasonic power of 300W, a frequency of 20kHz, and a treatment time of 20 to 40 minutes.

2) Concentrate the microfibrillated cellulose after the ultrasonic treatment in step 1) to a concentration of 10% by mass, and use a PFI refiner to perform fine fibrillation treatment, and the processing rotation number is 20,000 to 60,000 revolutions to further improve the microfibrillation The degree of fibrillation of cellulose makes the whole raw material form a highly branched and uniform network of fine fibers.

3) Dilute the microfibrillated cellulose after the fibrillation treatment in step 2) with water to a concentration of 2% to 8% by mass, and then add filler—light calcium carbonate/talcum powder. After mixing uniformly under high shear force, let stand for 1-5 seconds to form filler/MFC pre-envelope dispersion system. Wherein, the light calcium carbonate/talcum powder accounts for 70%-90% of the total solid matter in the filler/MFC pre-envelope dispersion system.

4) Add the retention and drainage aid cationic polyacrylamide according to the mass percentage of 0.02% to 0.06% of the solid matter in the filler/MFC pre-envelope dispersion system, and form a relatively stable filler/MFC envelope after low-shear mixing. body dispersion.

5) The filler/MFC inclusion body dispersion formed in step 4) is added to common chemical pulp for low-shear mixing to form a total dispersion. Wherein, the solid content in the dispersion system of the filler/MFC inclusion body is 45% to 70% of the total mass of solids in the total dispersion system after adding the pulp. Then it is quickly added to the sheet former for paper forming and drying. That is to obtain highly filled paper with microfibrillated cellulose enveloping retention.

Example 1

A kind of microfibrillated cellulose enveloping aid retention high filling papermaking process, comprises the following steps:

1) First, dilute the industrial microfibrillated cellulose product with water to a concentration of 1% by mass, and then perform ultrasonic treatment at room temperature, with ultrasonic power of 300W, frequency of 20kHz, and treatment time of 20min.

2) Concentrate the microfibrillated cellulose after the ultrasonic treatment in step 1) to a concentration of 10% by mass, and use a PFI refiner to perform fine fibrillation treatment, and the number of processing rotations is 60,000 revolutions to further improve the quality of the microfibrillated cellulose. The degree of fibrillation makes the whole raw material form a network of fine fibers with high branching degree and uniformity.

3) Dilute the microfibrillated cellulose after the fibrillation treatment in step 2) with water to a concentration of 8% by mass, and then add filler—light calcium carbonate. After mixing uniformly under high shear force, let stand for 1-5 seconds to form filler/MFC pre-envelope dispersion system. Wherein, light calcium carbonate accounts for 70% of the total solid matter in the filler/MFC pre-envelope dispersion system.

4) Add the retention and drainage aid cationic polyacrylamide according to the solid content of 0.02% in the filler/MFC pre-envelope dispersion system, and form a relatively stable filler/MFC inclusion body dispersion system after low-shear mixing. .

5) The filler/MFC inclusion body dispersion formed in step 4) is added to common chemical pulp for low-shear mixing to form a total dispersion. Wherein, the solid content in the dispersion system of the filler/MFC inclusion body is 45% of the total mass of solids in the total dispersion system after adding the pulp. Then it is quickly added to the sheet former for paper forming and drying. That is to obtain highly filled paper with microfibrillated cellulose enveloping retention.

Example 2

A kind of microfibrillated cellulose enveloping aid retention high filling papermaking process, comprises the following steps:

1) First, dilute the industrial microfibrillated cellulose product with water to a concentration of 3% by mass, and then perform ultrasonic treatment at room temperature, with ultrasonic power of 300W, frequency of 20kHz, and treatment time of 40min.

2) Concentrate the microfibrillated cellulose after the ultrasonic treatment in step 1) to a concentration of 10% by mass, and use a PFI refiner to perform fine fibrillation treatment, and the number of processing rotations is 20,000 revolutions to further improve the quality of the microfibrillated cellulose. The degree of fibrillation makes the whole raw material form a highly branched and uniform microfiber network.

3) Dilute the microfibrillated cellulose after the fibrillation treatment in step 2) with water to a concentration of 5% by mass, and then add filler—light calcium carbonate. After mixing uniformly under high shear force, let stand for 1-5 seconds to form filler/MFC pre-envelope dispersion system. Wherein, light calcium carbonate accounts for 90% of the total solid matter in the filler/MFC pre-envelope dispersion system.

4) Add the retention and drainage aid cationic polyacrylamide according to the solid content of 0.03% in the filler/MFC pre-envelope dispersion system, and form a relatively stable filler/MFC inclusion body dispersion system after low-shear mixing. .

5) The filler/MFC inclusion body dispersion formed in step 4) is added to common chemical pulp for low-shear mixing to form a total dispersion. Wherein, the solid content in the filler/MFC inclusion body dispersion system is 70% of the total solid content in the total dispersion system after adding the pulp. Then it is quickly added to the sheet former for paper forming and drying. That is to obtain highly filled paper with microfibrillated cellulose enveloping retention.

Example 3

A kind of microfibrillated cellulose enveloping aid retention high filling papermaking process, comprises the following steps:

1) First, dilute the industrial microfibrillated cellulose product with water to a concentration of 5% by mass, and then perform ultrasonic treatment at room temperature, with ultrasonic power of 300W, frequency of 20kHz, and treatment time of 30min.

2) Concentrate the microfibrillated cellulose after the ultrasonic treatment in step 1) to a concentration of 10% by mass, and use a PFI refiner to perform fine fibrillation treatment, and the number of processing rotations is 50,000 revolutions to further improve the quality of the microfibrillated cellulose. The degree of fibrillation makes the whole raw material form a highly branched and uniform microfiber network.

3) Dilute the microfibrillated cellulose after the fibrillation treatment in step 2) with water to a concentration of 8% by mass, and then add filler—talcum powder. After mixing uniformly under high shear force, let stand for 1-5 seconds to form filler/MFC pre-envelope dispersion system. Wherein, the talc powder accounts for 80% of the total solid matter in the filler/MFC pre-envelope dispersion system.

4) Add the retention and drainage aid cationic polyacrylamide according to the solid matter percentage of 0.06% in the filler/MFC pre-envelope dispersion system, and form a relatively stable filler/MFC inclusion body dispersion system after low-shear mixing. .

5) The filler/MFC inclusion body dispersion formed in step 4) is added to common chemical pulp for low-shear mixing to form a total dispersion. Wherein, the solid content in the dispersion system of the filler/MFC inclusion body is 55% of the total mass of solids in the total dispersion system after adding the pulp. Then it is quickly added to the sheet former for paper forming and drying. That is to obtain highly filled paper with microfibrillated cellulose enveloping retention.

Example 4

A kind of microfibrillated cellulose enveloping aid retention high filling papermaking process, comprises the following steps:

1) First, dilute the industrial microfibrillated cellulose product with water to a concentration of 4% by mass, and then perform ultrasonic treatment at room temperature, with ultrasonic power of 300W, frequency of 20kHz, and treatment time of 40min.

2) Concentrate the microfibrillated cellulose after the ultrasonic treatment in step 1) to a concentration of 10% by mass, and use a PFI refiner to perform fine fibrillation treatment with a processing rotation number of 45,000 revolutions to further improve the microfibrillated cellulose The degree of fibrillation makes the whole raw material form a highly branched and uniform microfiber network.

3) Dilute the microfibrillated cellulose after the fibrillation treatment in step 2) with water to a concentration of 6% by mass, and then add filler—light calcium carbonate. After mixing uniformly under high shear force, let stand for 1-5 seconds to form filler/MFC pre-envelope dispersion system. Wherein, light calcium carbonate accounts for 75% of the total solid matter in the filler/MFC pre-envelope dispersion system.

4) Add the retention and drainage aid cationic polyacrylamide according to the solid content of 0.05% in the filler/MFC pre-envelope dispersion system, and form a relatively stable filler/MFC inclusion body dispersion system after low-shear mixing .

5) The filler/MFC inclusion body dispersion formed in step 4) is added to common chemical pulp for low-shear mixing to form a total dispersion. Wherein, the solid content in the filler/MFC inclusion body dispersion system is 60% of the total solid content in the total dispersion system after adding the pulp. Then it is quickly added to the sheet former for paper forming and drying. That is to obtain highly filled paper with microfibrillated cellulose enveloping retention.

Example 5

A kind of microfibrillated cellulose enveloping aid retention high filling papermaking process, comprises the following steps:

1) First, dilute the industrial microfibrillated cellulose product with water to a concentration of 2% by mass, and then perform ultrasonic treatment at room temperature, with ultrasonic power of 300W, frequency of 20kHz, and treatment time of 30min.

2) Concentrate the microfibrillated cellulose after the ultrasonic treatment in step 1) to a concentration of 10% by mass, and use a PFI refiner to perform fine fibrillation treatment, and the number of processing rotations is 35,000 revolutions to further improve the quality of the microfibrillated cellulose. The degree of fibrillation makes the whole raw material form a highly branched and uniform microfiber network.

3) Dilute the microfibrillated cellulose after the fibrillation treatment in step 2) with water to a concentration of 8% by mass, and then add filler—talcum powder. After mixing uniformly under high shear force, let stand for 1-5 seconds to form filler/MFC pre-envelope dispersion system. Wherein, the talc powder accounts for 80% of the total solid matter in the filler/MFC pre-envelope dispersion system.

4) Add the retention and drainage aid cationic polyacrylamide according to the solid content of 0.02% in the filler/MFC pre-envelope dispersion system, and form a relatively stable filler/MFC inclusion body dispersion system after low-shear mixing. .

5) The filler/MFC inclusion body dispersion formed in step 4) is added to common chemical pulp for low-shear mixing to form a total dispersion. Wherein, the solid content in the dispersion system of the filler/MFC inclusion body is 50% of the total mass of solids in the total dispersion system after adding the pulp. Then it is quickly added to the sheet former for paper forming and drying. That is to obtain highly filled paper with microfibrillated cellulose enveloping retention.

The invention aims at the technical problem of papermaking that the addition of fillers in paper will cause the loss of paper strength and the retention rate of fillers is low in the process of high filling. Microfibrillated cellulose is used as a means of retention and reinforcement. Microfibrillated cellulose has a high degree of branching. During papermaking wet forming, the overlapping of each other can form a fine network structure that is much larger than ordinary pulp fibers, which is beneficial to the filler particles. The entrapment and envelope of the paper can significantly improve the retention rate of the filler in the paper. In addition, the specific surface of microfibrillated cellulose is extremely large, and the free hydroxyl groups on the surface are extremely rich, which can form hydrogen bonds several times that of ordinary cellulose fibers, which solves the problem of poor strength of paper with high filler content. Finally, the contradiction between paper strength and high filling amount in the high filling technology is better resolved. The price of the filler is much lower than that of pulp fiber, so this invention is beneficial to reduce the production cost of paper, improve the profit of the enterprise, and alleviate the shortage of fiber raw material resources in the paper industry. Under the process of the present invention: when the filler content is 54.18%, the tensile index of the paper reaches 30.21N·m/g; under the ordinary process: when the filler content is 24.79%, the tensile index of the paper is 29.63N·m/g. The filler content of the paper prepared by the invention can be as high as more than 54%, while the strength can still reach the strength of the paper with the filler content of 25% in the common papermaking process.

Claims (1)

1. a kind of fento cellulose envelope retention high-filling paper technology, it is characterised in that comprise the following steps：

1) first, industrial fibrillation cellulose products are diluted with water to the concentration that mass percent is 1%～5%, Ran Hou Ultrasonication is carried out under normal temperature；The parameter of ultrasonication is：Ultrasonic power is 300W, frequency 20kHz, process time 20 ～40min；

2) by step 1) the fento cellulose after ultrasonication is concentrated into the concentration that mass percent is 10%, using PFI Fiberizer carries out fibrillating process；The process revolution for controlling PFI fiberizers is 20000～60000 turns；

3) by step 2) fibrillating process after fento cellulose be diluted with water for mass percent be 2%～8% it is dense Degree, is subsequently adding filler；Stand after high shear force is well mixed and form filler/MFC preenvelop body disperse systems；Wherein, filler It is 70%～90% to account for total solid mass percent in filler/MFC preenvelop body disperse systems；Described filler is precipitated calcium carbonate Or talcum powder；

4) retention is added to help by the amount of solid quality percentage 0.02%～0.06% in filler/MFC preenvelop body disperse systems Filtering agent PAMC, low shear mixing uniformly forms afterwards filler/MFC enveloping solid disperse systems；

5) by step 4) in the filler/MFC enveloping solids disperse system that formed add that low-shearing force mixing is carried out in chemical pulp paper pulp is equal Even formation total dispersion system；Wherein, solid content is solid content gross mass in total dispersion system in filler/MFC enveloping solid disperse systems 45%～70%；Then being rapidly added in sheet forming apparatus carries out manufacture paper with pulp shaping, drying, obtains fento cellulose envelope and helps The high-filling paper for staying；The high-filling Fillers in Paper content of obtained fento cellulose envelope retention is 54.18%, paper Tensile index is 30.21Nm/g；

Step 3) in high shear force be well mixed after stand 1～5 second formed filler/MFC preenvelop body disperse systems.