JPH0711113B2 - Recycled paper manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a method for producing recycled paper with low oil content by using a waste paper of stainless steel strip interleaving paper containing and adhering a rolling oil mainly composed of mineral oil as a raw material. Regarding

(Prior Art) When cold-rolling or skin-passing a metal strip, a rolling oil containing mineral oil as a main component is used. However, when a surface flaw is easily noticeable, such as a cold-rolled steel strip of stainless steel, a coil is used. Insert interleaving paper when winding to prevent scratches. For this reason, when the coil is rewound and processed, a large amount of waste paper containing rolling oil and contained waste paper is generated. However, since the interleaving paper is a good material, even if it becomes a waste paper, it is not thrown away and has been used as a raw material for manufacturing recycled paper.

A conventional general method for producing recycled paper using this waste paper as a raw material is to make the waste paper into a roll or a compressed block, and put it in a disintegrator having a shearing blade at the bottom, and then add industrial water or white water to the waste paper concentration Inject it to about 5.5 wt%, then blow steam directly, rotate the shear blade and add alkali (for example, caustic soda) to obtain a temperature of about 60 ° C.
The waste paper is disintegrated into fibers by stirring for about 90 minutes.
When the waste paper is disintegrated into a porridge, dehydration and water washing are repeated to remove alkali and rolling oil, and papermaking is performed. The reason for adding an alkali during the disintegration of waste paper by this method is to accelerate the removal of mineral oil, vegetable oil or general dirt adhering to the waste paper, and caustic soda is usually added in an amount of about 1 wt% of the waste paper.

(Problems to be Solved by the Invention) However, when recycled paper is manufactured by using only waste paper having a deposit and content of mineral oil of 10 wt% or more as a raw material by such a manufacturing method, the recycled paper will not contain mineral oil. 2 to 3 wt% remains. Therefore, there have been various problems as described below when making paper or using recycled paper.

1. Problems in papermaking (1) When papermaking is continued, oil content is concentrated and accumulated on the net roll of the papermaking machine, and sometimes it is mixed in the product,
It becomes a quality defect called "floating seed".

(2) In the drying step after paper making, the oil content evaporates, and the oil particles are dispersed and suspended in the air, which causes discomfort to the worker and contaminates peripheral equipment. Further, in this drying process, unevenness in the oil content and the resulting non-uniformity of the water content tend to cause dry spots, and the product is liable to lose its shape and wrinkles easily. To prevent this shape defect and the occurrence of wrinkles, it is sufficient to dry it excessively, but when it is excessively dried, it becomes stiff like dried seaweed, and when it is used in a high humidity period, it will drastically remove water. Wrinkles are generated by absorption, and the volume changes abruptly to discharge the contained impurities. Furthermore, since excessive drying requires a large amount of heat, the drying cost becomes high, which is not preferable.

2.Problems with recycled paper (1) Inserting interleaving paper at the time of stacking in the case of materials such as scratches, blemishes, and cracks that tend to occur on the surface when placed directly on top of each other, such as plate-shaped metal, glass, and plastic But
When recycled paper is used as an interleaving paper, oil is transferred to the surface of the material and becomes cloudy, which significantly reduces the commercial value of the material.

(2) The paper fibers composing the paper become slippery due to the oil, and the paper strength is reduced. For this reason, when it is used for printing paper, for example, it is caught by the guide roll of the printing machine and the workability is reduced.

(3) Since the reaction with the sizing agent is likely to be non-uniform, the printing ink does not ride well and printing defects occur.

(4) Since mineral oil generally has high electric insulation, paper containing mineral oil is easily charged with electricity. For example, when used as interleaving paper for metal plates, the metal plate and interleaving paper are difficult to separate, and the metal strip is coiled. When inserting the interleaving paper when winding the interleaving paper in the shape of a coil, or when winding the interleaving paper in the form of a coil, the electric discharge causes electric discomfort to the operator and also damages electric equipment of the facility.

As described above, since there are various problems in the conventional method for producing recycled paper mainly made from waste paper having mineral oil adhered and contained, the present invention provides a method for producing recycled paper that solves the above problems. It is a thing.

(Means for Solving Problems) In the present invention, when the waste paper is disintegrated into fibers by an disintegrator with an alkaline aqueous solution, a deoiling agent for mineral oil is added to emulsify and disperse the mineral oil to separate the mineral oil from the fibers. In this way, it is possible to solve the papermaking problem and to manufacture recycled paper having a low oil content.

That is, the present invention is mainly applied with a rolling oil consisting of mineral oil, and the waste paper of the stainless steel strip interleaving paper containing the oil is added with a deoiling agent to be disintegrated into fibers with an alkaline aqueous solution to deoil, and then the alkali and deoiling agent are removed. The present invention provides a method for producing recycled paper, which is characterized in that

In the present invention, the alkali concentration of the alkaline aqueous solution is usually 1 wt% with respect to the waste paper as in the conventional method, but 0.5 to 2.
It should be in the range of 0 wt%. The type of the deoiling agent is not particularly limited and may be a commercially available product, but it is preferable that the alkaline aqueous solution at the time of disaggregation is kept at 60 to 90 ° C. and the contact between the deoiling agent and the waste paper is 10 minutes or more. Further, when the waste paper has a high oil content, it is possible to blend waste paper or pulp that does not contain oil and does not contain oil.

Next, the present invention will be described with reference to examples.

(Embodiment) FIG. 1 shows a manufacturing process of the present invention. The disintegrator 1 is an iron bottomed cylinder, and has an opening 2 at the top, a baffle plate 3 at the inner side surface, and a bottom. It has a shearing blade 4 that horizontally rotates and a steam inlet 5. To the disintegrator 1, the waste paper 7 with oil attached thereto was first charged by the conveyor 6, and then white water (engineering water) was added so that the concentration of the waste paper 7 became about 5.5 wt%. In this state, rotate the shearing blade 4 to disintegrate the waste paper 7 and remove the caustic soda from the waste paper 1 w
After adding t% and a degreasing agent as shown in Table 1 in terms of waste paper without oil adhesion, the shear blade 4 was rotated at a temperature of 80 ° C. for 40 minutes for disaggregation and deoiling to make the waste paper a porridge. After that, the shearing blade 4 is stopped, and the porridge-like material is sent by the pump 8 to the raw material storage tank 9 for papermaking, where it is once stored, and then the pump 10 is used for the sizing machine 11.
To the first compression filter washer 12 having a pair of mesh rolls. Here, after compressing and partially dehydrating, it is dealkalized and deoiled to a water content of about 75 wt%, then sent to the raw material diluting device 13 while sprinkling white water (working water), and adding white water (working water). I made itchy again. After that, the porridge was sent to the second compression filtration washing machine 14 having the same structure as the first compression filtration washing machine 12 by the pump 15 and was dehydrated again to have a water content of about 75 wt%, and then white water (engineering water). While sending it to the filter washing machine 16, performs the final washing and filtration,
After that, paper was made according to a conventional method to produce recycled paper.

Table 1 shows the relationship between the oil content in the raw material (waste paper), the type of the deoiling agent used, and the oil content in the recycled paper.

By selecting the type of deoiling agent from Table 1 and deoiling, the oil content of recycled paper can be made considerably lower than before.

FIG. 2 shows the contact time between the waste paper 7 and the degreasing agent when the deoiling agent C shown in Table 1 was used as the degreasing agent when the waste paper 7 was disintegrated. In order to reduce it to 2% or less, the contact time must be 10 minutes or more.

Further, FIG. 3 shows the relationship between the temperature at the time of disaggregation and the addition amount of the deoiling agent C. In order to reduce the oil content of recycled paper to 2% or less of the conventional temperature, the temperature should be 60 to 90%. Must be ℃.

(Effects) According to the production method of the present invention as described above, the oil content of recycled paper can be made lower than before, so that the problems of papermaking and recycled paper, which have hitherto been problems, are eliminated.

[Brief description of drawings]

FIG. 1 is a manufacturing process according to the present invention, FIG. 2 is a graph showing the contact time between the deoiling agent C used in the examples and the waste paper when disintegrating the waste paper, and FIG. 3 is the addition of the deoiling agent C. It is a graph which shows the relationship between the amount and the temperature at the time of disaggregation. 1 ... disintegrator, 2 ... opening, 3 ... baffle plate, 4 ... shear blade, 5 ... steam inlet, 6 ... conveyor, 7 ...
Waste paper, 8 ... Pump, 9 ... Paper making material storage tank, 10 ... Pump, 11 ... Granulator, 12 ... First compression filtration washing machine, 13 ...
… Raw material diluter, 14 …… 2nd compression filtration washing machine, 15 …… Pump, 16 …… Filtration washing machine,

Claims (5)

[Claims] Claims: 1. A rolling oil consisting mainly of mineral oil and a waste paper of stainless steel strip interleaving paper containing the oil are added with a deoiling agent and disintegrated into fibrous form with an alkaline aqueous solution for deoiling, and then the alkali and the deoiling agent are removed. A method for producing recycled paper, which comprises: 2. The method for producing recycled paper according to claim 1, wherein the alkaline concentration of the alkaline aqueous solution is 0.5 to 2.0 wt% of caustic soda added to the waste paper. 3. The method for producing recycled paper according to claim 1, wherein the waste paper is disintegrated and deoiled by introducing an alkaline aqueous solution and a deoiling agent after putting the waste paper in the disintegrator. . 4. The method for producing recycled paper according to claim 1, wherein the waste paper is mixed with a waste paper or pulp that does not contain or contain mineral oil. 5. The method for producing recycled paper according to any one of claims 1 to 4, wherein the oil content of the deoiled recycled paper is 2% or less.