JP2000248486A - Papermaking of paper mixed with fine bubble - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of the use of a chemical mucilaginous agent, such as expensiveness of a cost for procurement of the chemical mucilaginous agent, and requirement of operation time, power cost, an installing space for equipment, when carrying out the papermaking by mixing the chemical mucilaginous agent with a pulp suspension. SOLUTION: A finely bubbled water including fine bubbles not floating-up in the water is joined to a pulp suspension to stick the fine bubbles in the finely bubbled water to the pulp in the pulp suspension, and the pulp suspension containing the pulp with the bubbles is supplied to a papermaking cylinder 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking method in which the use of a chemical thickener for preventing the dispersion and sedimentation of pulp in a pulp suspension is eliminated or the amount of use is reduced to reduce the amount of use.

[0002]

2. Description of the Related Art Conventionally, a stock solution of pulp having a pulp concentration of about 0.2% is prepared by mixing a pulp suspension with a dilution water of a chemical thickener such as polyethylene oxide for preventing dispersion and sedimentation of pulp. Supply and paper making.

[0003]

In the above conventional method,
In addition to increasing the cost for obtaining the chemical thickener, the time required for dissolution for diluting the obtained chemical thickener, power cost, installation space for equipment, and the like are required. In addition, since the chemical adhesive has viscosity and foaming property, scale and slime are generated, staining the papermaking cylinder and blanket, and causing paper breakage which is a trouble of the paper made. In addition, when dissolved in water, it is liable to be scattered, adhered to the surroundings, and made the working environment slippery.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention does not use a chemical adhesive or reduces the amount of paper used to make paper. The method is characterized in that fine bubble water containing fine bubbles is mixed with a pulp suspension, and fine bubbles of the fine bubble water adhere to pulp in the pulp suspension and are supplied to a papermaking cylinder.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Is a circular net-type papermaking cylinder 11 which is driven to rotate in the direction of the arrow to make paper, and a papermaking stock solution supply for supplying a stock solution of pulp suspension and white water having a pulp concentration of about 0.2% to the papermaking cylinder. A papermaking apparatus including an apparatus 12, and a white water pit 13 is provided below the papermaking apparatus 10 for receiving a liquid flowing through the papermaking cylinder and flowing down from the papermaking stock solution supplied to the papermaking cylinder by the apparatus. Incidentally, the white water pit 13 Yes to overflow the pit 14 for receiving the white water that overflowed provided, white water that has flowed into the overflow pit is supplied as washing water to the washing step of bleached pulp pump P _2.

The apparatus 12 for supplying a stock solution to a papermaking cylinder in the embodiment of FIG. 1 includes a substantially U-shaped head box 15, which is provided at the upper end of one end with a papermaking stock solution at an obliquely upward circumferential direction of the papermaking cylinder. A bat 16 is provided which is brought into contact with the surface 11a and is poured. The upper surface of the pad 16 is open. The inside of the other end of the head box 15 has a mixing overflowing part 18 whose upper surface is open and whose lower end is closed by a partition wall 17 having a low height,
It is divided into a communication section 19 connected from below. Then, a feed pipe 20 for a pulp suspension having a pulp concentration of about 0.5% ± 0.1% is provided in the mixing overflow section 18 of the head box.
And the white water supply pipe 21 from the white water pit 13 rush from above.

A pump P ₁ for discharging and supplying white water in a white water pit, an air supply pipe 23 for supplying compressed air from an air compressor 22, and a known fine bubble production mixer 24 are connected to the white water supply pipe 21. from the pump P ₁ is white water pit pressurized air mixed from the air compressor 22 is in the white water pumping Te sucking, fine bubble production mixer of the lack sized to Ho Isuzu floating pressurized air in the white water in the water About 10
Micronization, preferably smaller than 10 microns.

As a result, the pulp suspension is supplied to the mixing overflow portion 18 of the head box downward from the liquid supply pipe 20 which has entered from above, and at the same time, 10% of the pulp suspension is supplied from the white water supply pipe 21.
Microbubble water containing microbubbles of a micron or smaller size is supplied downward, and once mixed with the pulp suspension, descends and then ascends to mix uniformly so that the pulp concentration is 0. .2% of the stock solution, and then overflows over the upper end of the partition wall 17 into the communication section 19, flows from the communication section 19 to the vat 16, flows into the papermaking cylinder 11, and flows into the cylinder surface. , Forming a wet paper formation, separated by the coach roll 9 and transported to the dry part.

In the embodiment of FIG. 2, the same components as those of FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. The vat 16 of the papermaking stock solution supply device 12 to the papermaking cylinder 11 in the embodiment of FIG. 2 is a closed box having a slit facing the papermaking cylinder, and the slit of the vat 16 is provided inside the papermaking cylinder 11. There is provided a fixed suction box 11 'for sucking white water of the stock undiluted paper ejected from the cylinder toward the peripheral surface of the cylinder. The white water sucked into the suction box is supplied to the white water pit 13 from the center of the cylinder.

At the connection point 25, a white water supply pipe 21 from the white water pit 13 is connected at an intermediate point of the liquid supply pipe 20 for supplying the pulp suspension to the vat 16. This white water supply pipe 21
Also the pump P ₁ , the air supply pipe 2 from the air compressor 22
3. Since the fine bubble production mixer 24 is connected, a pulp suspension having a pulp concentration of about 0.5% supplied toward the vat 16 by the liquid supply pipe 20 is connected at the connection point 25 by one.
Microbubble water of white water containing microbubbles of 0 micron or smaller is supplied from the water supply pipe 21 and uniformly mixed to form a stock solution having a pulp concentration of about 0.2% and flows into the vat 16. Sent from the vat to the papermaking cylinder 11
To form a wet paper web on the peripheral surface of the cylinder, separated by the coach roll 9 and conveyed to the dry part.

In both of the embodiments shown in FIGS. 1 and 2, in order to increase the efficiency of the fine bubble production mixer 24, as shown in an enlarged view in FIG. A porous gas diffuser 26 is attached to the end and positioned inside the water supply pipe 21. By increasing the pressure of the air compressor 22 to, for example, 3 kg / cm ² , bubbles having a diameter of about 2 mm ± 1 mm are supplied from the gas diffuser 26. Tube 21
It is preferable to mix with white water flowing through.

The amount of air of fine bubbles mixed in the stock solution supplied to the papermaking cylinder 11 is 10 to 25% of the amount of stock solution (papermaking water amount). It is preferable that the supply amount of compressed air from the air compressor 22 can be adjusted by a control valve 28 connected upstream of the valve 27 according to the freeness (freeness) of the stock solution.

Further, air vents 29 are provided on horizontal portions of the liquid supply pipe 20 and the water supply pipe 21 and on the upper wall of the bat 16 in FIG. To prevent the formation of the wet paper web from being deteriorated.

Further, the overflow gutter 3 is provided on the back surface of the bat 16 in the embodiment of FIG.
0 is provided to discharge the combined coarse bubbles and the floating pulp that has floated to the overflow gutter 30 with overflow water, thereby preventing the formation of wet paper from being deteriorated. The liquid discharged into the overflow gutters 30 and 30 is supplied to the overflow pit 14 of the white water pit 13 and used as washing water for bleached pulp. Further, it is preferable that the supply pressure of the pulp suspension supplied to the mixing overflow portion 18 of the head box and the supply pressure of the white water mixed with the fine bubbles are substantially the same. For this reason, a pressure gauge 31 is mounted on the water surface of the liquid supply pipe 20 and the water supply pipe 21 so that the supply pressure can be measured, and the pulp suspension and the pressure gauges 31 and 31 are made to have substantially the same value. It is preferable that the supply amount of white water mixed with fine bubbles can be adjusted.

In the embodiment shown in FIG. 2, the water supply pipe 21 containing fine air bubbles is connected to the pulp suspension liquid supply pipe 20 at an angle α of about 45 ° at a connection point 25 as shown in FIG. It is preferable that the pulp suspension, which is connected so as to be merged, flows downstream in the liquid supply pipe 20, and the white water containing microbubbles at the connection point 25 at almost the same pressure, are mixed and mixed. Reference numerals 31 and 31 denote pressure gauges provided near the junction of the two pipes 20 and 21.

[0016]

As is apparent from the above description, according to the present invention, the papermaking stock solution supplied from the papermaking stock solution supply device 12 to the papermaking cylinder 11 contains an appropriate amount of fine particles which do not float in the water blown into the white water. Since bubbles are present and these fine bubbles adhere to pulp fibers having a specific gravity of about 1.2 to 1.5 to suppress sedimentation and disperse the pulp fibers by the flow rate of the bubbles, even without using a conventional chemical thickener. Even when used, a wet paper can be formed by a papermaking cylinder by using only a very small amount. Accordingly, the cost can be reduced and the occurrence of stains on the papermaking cylinder and the blanket and the occurrence of paper breakage can be reduced because the chemical tackifier is not used. or,
Due to the mixing of the fine bubbles, the concentration of dissolved oxygen in the white water flowing down from the papermaking cylinder 11 to the white water pit 13 is increased, the odor of pulp in the mill disappears, the white water pit and the working environment are kept clean, and the wastewater is treated. The use of chemicals for is reduced.

When wet paper is adhered to the peripheral surface of the drying drum of the dry part and dried, and peeled off from the peripheral surface of the drying drum by a doctor to form crepe on the paper, the paper is appropriately applied to the peripheral surface of the drying drum. If it does not adhere to the crepe, crepe cannot be formed. Therefore, when producing creped paper, a small amount of a sizing agent is present in the stock solution in addition to the fine bubbles, and the wet paper thus formed is appropriately adhered to the peripheral surface of the drying drum and dried. Peel off with a doctor to get creped paper.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one embodiment of a papermaking method according to the present invention, in which a part is shown in an enlarged cross section.

FIG. 2 is an explanatory view of another embodiment of the papermaking method according to the present invention.

[Explanation of symbols]

 Reference Signs List 9 coach roll 10 papermaking apparatus 11 papermaking cylinder 12 papermaking stock solution supply device to papermaking cylinder 13 white water pit 20 pulp suspension supply pipe 21 white water supply pipe 22 air compressor 23 air supply pipe 24 fine bubble production mixer 26

Claims (1)

[Claims] 1. A microbubble water containing microbubbles that do not float in water is mixed with a pulp suspension, and microbubbles of the microbubble water adhere to the pulp in the pulp suspension and are supplied to a papermaking cylinder. A papermaking method containing fine bubbles.