JPH06316888A - Method for improving bonding characteristics of defibrillated waste paper by ozone - Google Patents

Abstract

PURPOSE:To improve the bonding characteristics of waste paper by ozone oxidation of its surface. CONSTITUTION:Lignin-contg. waste paper is put to dry defibrillation and brought into contact with vapor phase ozone at levels of 1-5wt.% of the lignin in said waste paper, thus accomplishing ozone oxidation of the surface of the lignin coexistent with the defibrillated fibers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the bonding characteristics of defibrated waste paper by ozone.

[0002]

2. Description of the Related Art Today, when the momentum for protecting the global environment has greatly increased, cellulose fibers made from valuable forest resources are used as pulp and paper, and are then recovered even if they are discarded as waste paper. Of course, it must be reused as effectively as possible.

[0003] Conventionally, waste paper is once collected and transported to a pulp and paper mill in a remote place, and in a device called pulper, water is added and stirred by a rotary blade to dissociate fibers into water, and chemical means is used. Deinking and separating the fibers by the flotation method, almost all of the fibers are used as raw materials for recycled paper.

[0004]

However, in the above-mentioned conventional waste paper recycling method, cellulose is shortened and hemicellulose and fibril structure (branch structure of fiber) disappear in the step of dissociating the fiber, and after the regeneration, It had a fundamental problem that paper strength was reduced.

Further, since the above-mentioned conventional waste paper recycling method uses a large amount of water for defibration, it has problems of wasting water resources and polluting waste water.

Furthermore, the above-mentioned conventional waste paper recycling method has a treatment factory in a remote place (mainly because a large amount of water resources can be obtained) from a large city where waste paper is usually most produced, and in reality, Since the processing factory is limited to a pulp and paper factory, there is a problem that the recovery and recycling rate cannot be improved easily due to the high costs such as recovery costs and processing costs.

Therefore, the present invention has been made to solve the above problems. Fibers recovered from waste paper are less likely to be entangled with each other and have poorer adhesiveness than fibers produced from natural wood.
In other words, in view of poor bonding characteristics, by suppressing these physical performance deterioration as much as possible, it can be used not only as a raw material for recycled paper but also for multiple purposes (for example, building materials), and as a result, the recovery and recycling rate is improved. Therefore, it is an object of the present invention to provide a method for improving the bonding property of defibrated waste paper by ozone, which can contribute to effective use of natural resources.

Still another object of the present invention is to provide a method for improving the bonding property of defibrated waste paper by ozone, which can be easily treated even in the suburbs where the waste paper is mainly generated. It is a thing.

[0009]

In order to solve the above-mentioned problems, the waste paper containing lignin is dry defibrated, and the weight ratio is set to the above-mentioned object. The technical means is characterized in that the surface of lignin coexisting with the defibrated fiber is oxidized by ozone by contacting with ozone in the gas phase within the range of 1% or more and 5% or more of the contained lignin. is there.

[0010]

Next, the operation of the method of the present invention will be described. For the sake of better understanding, pulp (hereinafter referred to as pulp fiber) is first described.
The structure of is explained. Pulp fibers are roughly classified into mechanical pulp fibers obtained by crushing wood with a refiner to dissociate fibers, and chemical pulp fibers obtained by cooking wood to remove lignin by a chemical method. Since the mechanical pulp fiber is not subjected to delignification treatment, as shown in "Fig. 3",
The outside of cellulose 100 is covered with hemicellulose 101, and the outside is covered with lignin 102. In addition,
"Fig. 3" is a schematic diagram, and actually, cellulose 100
Alternatively, there is a portion where the hemicellulose 101 is exposed, or a plurality of fibrous cellulose 100 is bundled, and each fibrous cellulose 100 or hemicellulose 101
Lignin 102 is linked to each other to form the lignin 102
Is also deep inside the cellulose 100 and the hemicellulose 101. Also, a large number of cellulose 1
A bundle of 00 or hemicellulose 101 is usually branched on the surface in a complicated manner.

Although not shown in the chemical pulp fiber, the lignin 102 in FIG. 3 is extremely small, but the chemical pulp fiber is not completely free of the lignin 102, and the cellulose 100 and hemicellulose are not present. 10
It is also lignin 102 that bundles the fibrous material consisting of 1
In general, the mechanical pulp fiber has a weight ratio of about 20 to 33.
%, About 2-4% of chemical pulp fiber lignin 102
Is included.

Usually, newspapers and newspapers are made of the above mechanical pulp fibers, and office papers and the like are made of chemical pulp fibers. However, when used papers are often mixed and collected. The amount of lignin contained is not always constant.

Therefore, according to the present invention, since the waste paper in which the mechanical pulp fibers and the chemical pulp fibers are mixed is dry defibrated, that is, the waste paper is dissociated into fluff fibers by applying a mechanical external force, it is not necessary to use water. It has the advantage that it can defibrate the desired treatment capacity with a small device and does not require wastewater treatment, but even if the fibers are mechanically dissociated better than used paper, the used paper is dissociated with water and stirring power. The probability that the fibers will be cut is greater than in the conventional example. However, mechanical dry defibration has the action of forming a branching portion in the fiber bundle, and when the conventional pulper is used, the branching portion melts or breaks and disappears. Is stripped off by an external force, but when an external force is applied at that time, a new branching part is generated, and as a result, the branching part is not reduced, and this branching part becomes entangled and becomes easy to connect to each other. It is a thing.

Further, in the method of the present invention, since the defibrated fiber is brought into contact with ozone in the gas phase, it exhibits an action of oxidizing contained lignin into ozone-oxidized lignin.

Since lignin has a complicated structure with a very large molecular weight and is a chemically stable substance, it is difficult to decompose and has poor adhesiveness. Therefore, it has a strong oxidizing power. When we tried to decompose ozone, it was found that ozone exhibited a selective decomposition effect on cellulose, contrary to the assumption that cellulose and hemicellulose would be decomposed before the decomposition of lignin.

Although ozone decomposes lignin, it does not decompose lignin having a molecular weight of 200 to 300 into a substance having a molecular weight of several to several tens, and the ozone-oxidized lignin of the present invention has its aromatic nucleus. The above-mentioned selective decomposition can be said within this range.

Originally, the surface of gnunn is physically flat and the reactivity is chemically small, but the ozone-oxidized lignin from which aromatic nuclei are cleaved has a rough surface. The effect of increasing the reactivity chemically, that is,
It has the effect of increasing the bonding characteristics.

Although ozone is said to selectively oxidize lignin, it does not oxidize cellulose and hemicellulose at all, and when the amount of ozone is large and the contact time with ozone is long, cellulose and hemicellulose are more likely than lignin. It is easily oxidized. If these are ozone-oxidized, the pulp fibers will be damaged. Therefore, in the present invention, by limiting the ozone to the range of not less than 1% and not more than 5% of the amount of lignin contained by weight, ozone is consumed by selectively oxidizing lignin, and the influence of ozone on cellulose and hemicellulose is reduced. It has the effect of minimizing it.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the method of the present invention, first, waste paper containing lignin is dry defibrated.

For dry defibration of waste paper, the defibration machine 2 as most clearly shown in FIG. 2 can be used. That is, 21 is the main body of the defibrating machine 2, and the main body 21 has an inlet 22 for taking in the used paper at one end side (the back side in FIG. 2) and discharging the defibrated pulp raw material for the other end side (to the front side in the figure) Outlet 2
3, and a drive shaft 26 horizontally provided in the main body 21 from one end side to the other end side (front side in the drawing).
A rotor 24 that rotates at high speed is stored.

The rotor 24 is composed of a large number of radial blades 24a, 24a, 24a, ... A large number of liners 25, 25, 25, ... Are provided along the front direction on the inner wall in order to form an uneven surface. A blower blade is attached to one end side (front side of the rotor 24) of the drive shaft 26, and the intake port 2
The used paper is pneumatically transported from 2 toward the discharge port 23.

Therefore, when the outlet 22 of the waste paper hopper 1 shown in FIG. 1 is communicated with the inlet 22 of the defibrating machine 2, the waste paper in the waste paper hopper 1 (in this embodiment, the waste paper 2
What is cut in advance to about 8 mm square is used. ) Sequentially flows into the defibration machine 2, collides with the inner wall of the main body 21 and is gradually defibrated into fluffy defibration fibers, and flows out from the outlet 23.

The pulp fibers are made of cellulose and various fillers (such as clay, talc, calcium carbonate, and titanium white, which are added to increase the smoothness, opacity, and weight of the paper). Since the printing ink and the like are attached, the defibrated fiber is separated from the filler and the attached matter, if necessary. In this separation, when waste paper is defibrated, it becomes a relatively long fibrous material and powdery filler and deposits with a small particle shape, so it is easy to separate the two. Conventional dry separation equipment such as sieving separation and classification separation. Can be used.

As shown in FIG. 1 as a concrete example of the dry separation device, if a cyclone separation device 4 having a conventionally known structure is used, large and heavy fibers having a small specific gravity are generated in the lower part of the cyclone body 41. Accumulation and small and light fillers and deposits having a large specific gravity flow out from the upper discharge port 42 along with the air flow and are collected by the bag filter 43 and the like. Further, the fibers accumulated in the lower portion of the cyclone body 41 of this cyclone separating device are airtight rotary feeder 4
It is sufficient to sequentially take out from the lower discharge port via 4.

According to the present invention, the surface of lignin coexisting with the defibrated fibers is oxidized by ozone by contacting with ozone in the gas phase within a range of not less than 1% and not more than 5% of the amount of lignin contained by weight.

The vapor phase ozone is a conventionally known ozone generator 3
In order to obtain vapor phase ozone, a discharge type ozonizer is suitable, and air or oxygen (preferably pure oxygen is used) as a raw material, and this raw material is passed through a discharge field. Oxygenate oxygen in raw materials.

In order to control the ozone oxidation reaction, contact frequency, contact time, temperature during reaction, etc. can be listed as condition items in addition to the mixing ratio of the lignin amount of the defibrated fiber and vapor phase ozone. In view of the strong oxidation reactivity of ozone, the reaction is completed within a short contact time of a few seconds to a few minutes, and there is no significant difference in reactivity under temperature conditions. The degree of oxidation can be controlled by controlling only the ratio.

Therefore, if the lignin content is clear, it is possible to secure a substantially stable degree of ozone oxidation by maintaining the mixing ratio of the defibrated fiber amount and the vapor phase ozone to a predetermined level. A certain amount of defibrated fibers may be stirred to form a fluidized bed, and the defibrated fibers being fluidized may be brought into contact with a fixed ratio of ozone gas. The contact between the two may be such that defibrated fibers and vapor-phase ozone are respectively prepared and mixed, but in the present embodiment, a predetermined ratio of vapor-phase ozone is contacted during defibration. Yes.

That is, the example of the apparatus shown in FIG. 1 continuously oxidizes mechanical pulp fibers by ozone, and 1 is a waste paper hopper, and the waste paper hopper 1 has a fixed amount feeder 11 such as a rotary feeder at the bottom thereof. Is provided, and the amount of used paper fed can be adjusted by controlling the operation of the quantitative feeding device 11.

The downstream end of the quantitative feeder 11 communicates with the inlet 22 of the defibrating machine 2, but the air inlet pipe 5 is provided in the inlet 22 in order to ensure uniform pneumatic transportation of waste paper. And the downstream side end of the constant quantity feeder 11 is connected to the air intake pipe 5.

The discharge port 3 of the ozone generator 3
1 is connected to the upstream side of the defibrating machine 2, specifically in the middle of the air intake pipe 4, so that ozone of the ozone generator 3 and waste paper of the hopper 1 both flow into the defibrating machine 2. is there. The outlet 31 of the ozone generator 3 is
A flow rate adjusting valve 33 is inserted in the middle of the connecting pipe 32 that connects the air intake pipe 5 with the air intake pipe 5, and the feed amount of vapor-phase ozone can be arbitrarily adjusted by the flow rate adjusting valve 33.

In the illustrated example, one end of a reflux pipe 34 is connected to the upstream side of the flow rate adjusting valve 33 of the connecting pipe 32, and the other end of the reflux pipe 34 is on the raw material intake port 35 side of the ozone generator 3. The flow meter 36 is attached to the reflux pipe 34, and the ozone supply amount is measured by the flow meter 36. It is needless to say that the flow meter 36 may be provided on the downstream side of the flow rate adjusting valve 33 of the connecting pipe 32. Further, when the ozone generator 3 has a built-in ozone discharge amount adjusting mechanism, the above flow rate adjusting is performed. Omit valve 33,
The ozone delivery amount may be measured from the operation of the amount adjusting mechanism.

The amount of lignin is measured by sampling a sample appropriately from the sampling valve 51 and analyzing it.
This value changes depending on the mixing ratio of mechanical pulp waste paper and chemical pulp waste paper, and it is desirable to perform sampling analysis frequently when the type of waste paper changes. In addition,
It is possible in the future to determine the amount of lignin from the change in color tone with an optical continuous analyzer.

Reference numeral 60 denotes a control panel which controls the amount of ozone fed and the amount of used paper fed (the number of rotations of the rotary feeder) to a predetermined ratio with reference to the lignin content. . That is, the amount of waste paper delivered per hour is detected from the number of revolutions of the rotary feeder 11, sampling analysis is performed to obtain the lignin amount by the input lignin content rate, and the flow rate adjustment valve 33 is controlled to deliver ozone. Is designed to be maintained at a predetermined level. Needless to say, the flowmeter 36 may detect the ozone feed amount and control the used paper feed amount. In addition, the output of the general ozone generator 3 is fixed, that is, the ozone generation amount per unit time is constant, but if this ozone generation amount is adjustable, of course, this ozone generation amount is adjusted. It is needless to say that the ozone feed amount is adjusted by referring to the control panel 60.

The amount of ozone was in the range of not less than 1% and not more than 5% of the amount of contained lignin, which was the amount necessary and sufficient for ozone oxidation of the surface of lignin. As a result of various measurements, 3 It was observed that the lignin surface was most efficiently oxidized at about 4%, and that ozone higher than that tends to directly act on the defibrated fiber and damage the fiber.

[0036]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, since waste paper is dry defibrated, it can be treated with a simple device, and since it does not use a large amount of water, it can be treated in the suburbs of the city.
It is possible to provide a method for improving the bonding property of defibrated waste paper by ozone in which the branch structure of the fiber is not lost.

Further, according to the present invention, since the contained lignin is oxidized with ozone to form ozone-oxidized lignin, the surface is uneven, the reactivity is increased, and the fibers are easily entangled. It is possible to provide a bonding characteristic improving method.

Mao, defibrated fiber obtained by the present invention,
Of course, it can be used as a recycled paper raw material, but it can be used in various ways, such as by heat-pressing it into a board, and then adding a binder to form a board for building materials. By doing so, the recycling rate can be improved and a great contribution can be made to effective use of resources.

[Brief description of drawings]

FIG. 1 is a front view of an example of an apparatus for carrying out the method of the present invention.

FIG. 2 is a vertical sectional view showing an example of a defibrating machine used in the present invention.

FIG. 3 is a schematic sectional view of pulp fibers.

[Explanation of symbols]

 1 Hopper 2 Defiberizer 3 Ozone generator 4 Cyclone separator

Claims (1)

[Claims] 1. Dry defibration of waste paper containing lignin,
In the defibrated waste paper by ozone, which is characterized in that the surface of lignin coexisting with defibrated fibers is oxidized by ozone by contacting with vapor phase ozone within the range of 1% or more and 5% or more of the lignin content in weight ratio. Bonding property improvement method.