CN108755241A - A method of improving bamboo pulp paper for daily use body paper water imbibition - Google Patents

Abstract

The invention belongs to the field of pulping and papermaking, and in particular relates to a method for improving the water absorption of bamboo pulp household paper base paper. The invention provides an easy-to-operate, environmentally friendly method for improving the water absorption of bamboo pulp household paper base paper, which is of great significance.

Description

A method for improving the water absorption of bamboo pulp household paper base paper

technical field

The invention belongs to the field of pulping and papermaking, and in particular relates to a method for improving the water absorption of bamboo pulp household paper base paper.

technical background

Household paper such as kitchen paper is an indispensable product in people's daily life. For household paper, water absorption is one of the important properties of paper. Kitchen paper on the market is mostly made of polyester fiber through spunlace composite technology, but its popularization and application as kitchen paper is limited due to its high cost of raw materials and complicated preparation process. Bamboo fiber has natural antibacterial, antibacterial, and bactericidal effects, and the household paper produced with bamboo fiber has good air permeability and comfort; so many people use it as a raw material for tissue paper, but bamboo fiber is very It is hard, easy to cut when beating, not easy to broom, and the outer layer of the primary wall and secondary wall of the fiber is easy to fluff, etc., which also limit its application in industry. Therefore, it is of great significance to research and develop a green and easy-to-operate method for improving the water absorption of bamboo pulp tissue paper base paper.

Contents of the invention

The purpose of the invention is to overcome the deficiencies of the prior art and provide a method for improving the water absorption of bamboo pulp household paper base paper.

Technical method of the present invention is summarized as follows:

A method for improving the water absorption of bamboo pulp household paper base paper, comprising the steps of:

Step 1: beating the bamboo pulp fiber raw material to a beating degree of 25°SR-35°SR or performing latent elimination to obtain fiber pulp;

Step 2: add water to adjust the mass concentration of the fiber slurry to 3wt%-10wt%, then add cellulase to treat the fiber slurry, so that the mass fraction of cellulase relative to the dry fiber slurry is 0.02wt%-0.1wt% , the enzyme treatment temperature is between 40°C-60°C, and the enzyme treatment time is 30-120min;

Step 3: adding nano-fibrillated cellulose (Nano-fibrillated Cellulose, NFC), the amount of NFC added is respectively 2wt%-10wt%;

Step 4: dilute the fiber slurry obtained in step 3 with water to a mass concentration of 0.2wt%-2wt%, and make household paper with a sheet machine, a dynamic paper former or a paper machine.

The fiber raw material is unbleached high-yield bamboo pulp or unbleached sulfate bamboo pulp.

The beating degree is preferably 32°SR.

The mass concentration of the fiber slurry is 5wt%.

The temperature is preferably 50°C.

Cellulase action time is preferably 60min.

The added amount of cellulase relative to the absolute dry mass of fiber pulp is preferably 0.1wt%

The added amount of the nanofibril cellulose relative to the absolute dry mass of the fiber slurry is preferably 10 wt%.

The present invention uses cellulase to treat the bamboo pulp fiber slurry, so that the fiber cell wall structure is loosened, the cohesion of the fiber is reduced, the degree of fibrillation of the fiber is improved, and more hydrophilic hydroxyl groups are exposed on the surface of the fiber, thereby improving the water absorption of the fiber properties; the large specific surface area and high aspect ratio of NFC make it easy to form a entangled network in water. This entangled gel-like structure will affect the interface phenomena of nanocellulose in water, such as swelling. and interfacial interaction, etc., which have an impact on making it have a strong water retention capacity and improve the water absorption of the paper; in addition, NFC contains a large number of hydroxyl groups, which belong to hydrophilic groups, and the hydroxyl group is relatively polar, which is easy to mix with media. Water with a large electrical constant combines to improve the water absorption of the paper. The cellulase and NFC involved in the present invention are green and safe. Compared with conventional chemical additives, they are beneficial to human health and have no pollution to the environment, and are of great significance for the production of safe, green and environment-friendly household paper.

Detailed ways

The following examples are intended to enable those skilled in the art to better understand the present invention, but do not limit the present invention in any way.

The activity of the cellulase in each embodiment was 700 EGU/g. The invention is not limited.

Embodiment 1: a kind of method that improves the water absorption of bamboo pulp household paper base paper comprises the steps:

Step 1: beating the unbleached high-yield bamboo pulp to a beating degree of 32°SR to obtain fiber pulp;

Step 2: Take a certain amount of fiber slurry, add water to adjust the mass concentration of the fiber slurry to 5wt%, add a certain amount of cellulase, so that the mass fraction of cellulase relative to the dry fiber slurry is 0.10 wt%, at a temperature of 50°C, the cellulase action time is 60 minutes;

Step 3: Take six parts of different quality fiber pulp according to a certain ratio, to ensure that the base paper after papermaking is the same quantitatively, add water to adjust the mass concentration of fiber pulp to 5wt%, and add different amounts of NFC to the six parts to make NFC The proportions of dry pulp are 0wt%, 2wt%, 4wt%, 6wt%, 8wt%, 10wt% respectively;

Step 4: Dilute the material obtained in step 3 with water to a mass concentration of 1 wt%, and use a sheet machine to make 40g/ ^m2 tissue paper base paper. See Table 1, 2, 3.

Table 1 Effect of NFC addition amount on water absorption of unbleached high-yield bamboo pulp tissue paper base paper

Table 2 Effect of NFC addition amount on strength properties of unbleached high-yield bamboo pulp tissue paper base paper

Table 3 Effect of NFC addition amount on bulk of unbleached high-yield bamboo pulp tissue paper base paper

It can be seen from Tables 1, 2, and 3 that for unbleached high-yield bamboo pulp, the fiber structure of bamboo pulp after cellulase treatment is loose, and the hydroxyl content exposed on the cellulose surface increases, so the bulkiness of the paper increases and the water absorption The water absorption increased from 6.80g/g to 8.32g/g, and the bulk thickness also increased from the original 3.78cm ³ /g to 4.26cm ³ /g; and the increase of hydroxyl groups after adding NFC will lead to more hydrogen bonds Combined, the strength of the paper is also improved, and its tensile index increases from the original 18.80N·m/g to 35.50N·m/g.

Embodiment 2: a kind of method that improves the water absorption of bamboo pulp household paper base paper comprises the steps:

Step 1: beating the unbleached sulfate bamboo pulp to a beating degree of 32°SR to obtain fiber pulp;

Step 2: Take a certain amount of fiber slurry, add water to adjust the mass concentration of the fiber slurry to 5wt%, add a certain amount of cellulase, so that the mass fraction of cellulase relative to the dry fiber slurry is 0.10 wt%, at a temperature of 50°C, the cellulase action time is 60 minutes;

Step 3: Take six parts of different quality fiber pulp according to a certain ratio, to ensure that the base paper after papermaking is the same quantitatively, add water to adjust the mass concentration of fiber pulp to 5wt%, and add different amounts of NFC to the six parts to make NFC The proportions of dry pulp are 0wt%, 2wt%, 4wt%, 6wt%, 8wt%, 10wt% respectively;

Step 4: Dilute the material obtained in step 3 with water to a mass concentration of 1 wt%, and use a sheet machine to make 40g/ ^m2 tissue paper base paper. See Table 4, 5, 6.

Table 4 Effect of NFC addition amount on water absorption of unbleached sulfate bamboo pulp tissue paper base paper

Table 5 Effect of NFC addition amount on strength properties of unbleached sulfate bamboo pulp tissue paper base paper

Table 6 Effect of NFC addition amount on bulk of unbleached sulfate bamboo pulp tissue paper base paper

It can be seen from Tables 4, 5, and 6 that for unbleached sulfate bamboo pulp, the fiber structure of the bamboo pulp after cellulase treatment is loose, and the hydroxyl content exposed on the cellulose surface increases, so the bulk of the paper is increased, and the water absorption is low. increase, the water absorption increased from 8.61g/g to 9.09g/g, and the bulk thickness also increased from the original 4.50cm ³ /g to 5.09cm ³ /g; and the increase of hydroxyl groups after adding NFC will lead to more hydrogen bonding , so that the strength of the paper has also been improved, and its tensile index has increased from the original 20.70N·m/g to 27.79N·m/g.

Claims (8)

1. a method for improving the water absorption of bamboo pulp household paper base paper is characterized in that comprising the steps: Step 1: beating the bamboo pulp fiber raw material to a beating degree of 25°SR-35°SR or performing latent elimination to obtain fiber pulp; Step 2: add water to adjust the mass concentration of the fiber slurry to 3wt%-10wt%, then add cellulase to treat the fiber slurry, so that the mass fraction of cellulase relative to the dry fiber slurry is 0.02wt%-0.1wt% , the enzyme treatment temperature is between 40°C-60°C, and the enzyme treatment time is 30-120min; Step 3: adding nano-fibrillated cellulose (Nano-fibrillated Cellulose, NFC), the amount of NFC added is respectively 2wt%-10wt%; Step 4: dilute the fiber slurry obtained in step 3 with water to a mass concentration of 0.2wt%-2wt%, and make household paper with a sheet machine, a dynamic paper former or a paper machine. 2. The method according to claim 1, characterized in that the fiber raw material is unbleached high-yield bamboo pulp or unbleached kraft bamboo pulp. 3. The method according to claim 1 or 2, characterized in that the beating degree is 32°SR. 4. The method according to claim 1 or 2, characterized in that the mass concentration of the fiber slurry is 5wt%. 5. The method according to claim 1 or 2, characterized in that said temperature is 50°C. 6. The method according to claim 1 or 2, characterized in that the cellulase action time is 60min. 7. The method according to claim 1 or 2, characterized in that the added amount of cellulase relative to the absolute dry weight of the fiber slurry is preferably 0.1 wt%. 8. The method according to claim 1 or 2, characterized in that the added amount of the nanofibril cellulose relative to the absolute dry weight of the fiber slurry is preferably 10 wt%.