JPS6325116B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application and Problems to be Solved by the Invention] The present invention relates to waste paper recycling technology. More specifically, by utilizing the physical properties of aromatic hydrocarbon compounds and/or their chlorinated products, the ink components, toner components, adhesive impurities, and pigments contained in waste paper are shaped to be easily separated, and then the adsorbent is used. This invention relates to a method for recycling waste paper with the aim of obtaining more carefully selected recycled fibers. [Prior Art] In recent years, with the development and spread of computers and copying machines, the amount of used paper made mainly of bleached chemical pulp has increased. However, it is difficult to remove ink using common treatment methods (for example, the flotation method and the water washing method). The reason for this is that the ink and toner adhere firmly to the fibers due to the role of the binder consisting of the polymeric resin in the ink and toner components, and the alkaline chemicals and surfactants used in conventional processing methods cannot be applied to the fibers. This is due to the lack of ink and toner removal effect. Therefore, pulp produced by recycling waste paper that is difficult to remove ink using conventional processing methods has a significantly higher amount of residual ink than pulp produced from waste paper printed with mineral oil-based inks, and is of good quality. The quality of the pulp could not be obtained. Establishing waste paper recycling technology that includes used paper that is difficult to remove ink will expand the use of used paper and is of great value from the viewpoint of resource and energy conservation. In conventional waste paper recycling technology, the incomplete recycling process is limited to toner-developed waste paper (for example, paper copied with Fuji Xerox 3207, paper copied with Canon PC20, paper printed with IBM 3800) and coated paper.
The target was waste paper printed in multiple colors on high-quality paper (hereinafter referred to as over-color/imitation waste paper). [Means for Solving the Problems] The present invention involves adding an aromatic hydrocarbon compound and/or a chlorinated product thereof having a melting point higher than room temperature to a pulp slurry of disintegrated waste paper; The pulp slurry is heated and mixed, then cooled to separate the solids containing ink and toner components from the waste paper, and an adsorbent is added to the pulp slurry, which is then heated and cooled. By doing so, the remaining aromatic hydrocarbon compounds and/or their chlorinated compounds are adsorbed onto the adsorbent, and the remaining aromatic hydrocarbon compounds and/or their chlorinated compounds are separated from the pulp slurry. Aromatic hydrocarbon compounds and/or chlorinated solids and an adsorbent that has adsorbed aromatic hydrocarbon compounds and chlorinated compounds are distilled or heated. This invention relates to a method for recycling used paper, which involves recycling and using the chlorinated substances and adsorbents. [Function] Hereinafter, the mechanism of the present invention will be explained in detail.
The aromatic hydrocarbon compound and/or its chlorinated compound used is hydrophobic and has the ability to soften or dissolve the binder component in the ink component and toner component. Peel it from the surface and disperse it in the slurry. Then, the so-called extractant of the binder in the ink component and toner component, which incorporates impurities such as the ink component and toner component dispersed by hydrophobic affinity into the above compound, and the ink component, toner component, and adhesive. It is thought to be a collector for impurities and pigments. The conditions for these to act as extractants and scavengers are:
It is necessary to have physical properties such as a solubility parameter of 7.0 to 12.0 and a melting point above room temperature, that is, a melting point within the range of 25°C to 100°C. When used, it is necessary to select an aromatic hydrocarbon compound and/or a chlorinated product thereof that is sparingly soluble in an aqueous solution.
That is, in the temperature range of 25℃ to 100℃, the aqueous solution 1
The substance must be a single substance or a mixture that does not dissolve more than 0.04g in the water. Therefore, as extractants and collectors, diphenyl, diphenylethane, diphenylmethane, diphenylbenzene (o), (m), naphthalene, chlorinated naphthalene, 1,4-dichloronaphthalene, dichlorobenzene (p), Aromatic hydrocarbon compounds such as triphenylmethane, diphenyl chloride, and pentamethylbenzene, and their chlorinated products, either alone or as a mixture. As the solubility parameter value, the value calculated from the boiling point of Hildebrad's equation was used as the optimum condition for deinking by dissolving or swelling the binder in the copied or printed waste paper. Add 1% or more by volume of aromatic hydrocarbon compounds and their chlorinated products (hereinafter referred to as extractants and scavengers) to the pulp slurry, either alone or as a mixture. The pulp slurry temperature is maintained above the melting point to extract and collect ink and toner components. These coagulated solids are then removed from the pulp slurry by cooling it below its melting point. After the above operations, when the pulp slurry is heated, extractants and scavengers remain in the form of oil-in-water, and it is necessary to remove these compounds in order to obtain a selected pulp slurry. Therefore, the pulp slurry is heated, the extractant, the scavenger is in the form of oil-in-water, and the beads are selected from the group consisting of polystyrene, polyethylene, polypropylene, polyvinyl chloride, polycarbonate,
By adding a fibrous, sheet-like foam, or a solid adsorbent that is not a foam, and cooling it, the extractant and scavenger are strongly adsorbed to the adsorbent, making use of the difference in specific gravity or shape. Remove from pulp slurry. Among the adsorbents used, materials such as polyethylene, polypropylene, polystyrene, polyester, and polyvinyl chloride, which have the property of dissolving or swelling with extractants and scavengers, are suitable as adsorbents, and materials other than those listed above are also suitable. Good results were obtained with the foam. Next, the solid matter of the extractant and collection agent containing ink components and toner components and the adsorbent that has adsorbed the extractant and collection agent are regenerated by distillation and heating, and when used, enough It acts as an extractant, collector, and adsorbent. It was found that it has a deinking effect. [Effects of the Invention] The waste paper recycling method according to the present invention described above has the following advantages. (1) Waste paper that is difficult to deink using conventional processing methods can be processed, and high-quality products with good whiteness and extremely low impurities can be obtained. It can also be applied to the recycling treatment of printed matter using mineral oil-based inks, and the quality of the recycled paper obtained is better than that obtained by conventional processing methods. (2) Very high yield. (3) Foreign substances such as pigments can be removed. [Example] Next, the present invention will be specifically explained with reference to Examples. Example 1 2 g of caustic soda was added to 100 g of waste paper (ash content 8.7%) consisting of 50% color and 50% paper (two-component toner) that had been copied with Fuji Xerox product 3207, and the pulp density was 15 using a kneader. A pulp slurry with a pulp concentration of 1%/10 was prepared. One of them (10g pulp amount) was collected in a beaker. 50 g of paradichlorobenzene was added to this pulp slurry, heated to 60°C, mixed for 10 minutes using a stirrer, and cooled to 40°C. Then, solid content was removed from the pulp slurry. Next, 10 g of polypropylene (manufactured by Mitsubishi Yuka Co., Ltd.) was added to the pulp slurry, heated and mixed at 60° C. for 20 minutes, and after cooling, the polypropylene that floated was scooped out. Next, a slurry with a pulp amount of 8.0 g was obtained. This paper stock was hand-sheeted using a TAPPI sheet machine, and the whiteness, residual ink rate, and ash content were measured using a Hunter whiteness meter, and the yield of only the fiber content was calculated.
The results are shown in Table 1. Example 2 The same procedure as in Example 1 was carried out using 100% old newspaper as the raw material. The results are shown in Table 1. Example 3 The same process as in Example 1 was carried out using 50% waste paper, 30% copied paper of Canon PC20 (one-component toner), and 20% paper printed with IBM 3800 as raw materials. . Example 4 Paper printed with 50% recycled paper and IBM3800
Using 50% as raw material, the same treatment as in Example 1 was carried out. Example 5 Naphthalene was used instead of paradichlorobenzene in Example 1, heated to 85°C, and then treated in the same manner as in Example 1, and instead of polypropylene,
Polyurethane sheet foam, polyethylene sheet and polystyrene were used, respectively. The results are shown in Table 2. Example 6 A mixture of chlorinated naphthalene and paradichlorobenzene was used in place of paradichlorobenzene in Example 1, and the mixture was heated to 70°C for treatment. The results are shown in Table 1. Example 7 The solid matter separated and removed from Examples 1 to 3 and the polypropylene were distilled, and the para-dichlorobenzene polypropylene recovered was used, and the same operation as in Example 1 was carried out, and it was reused up to 7 times. . The results are shown in Table 3. Comparative example 1 Color up 50%, Fuji Xerox 3207 copied paper 50
% of waste paper, 0.2 g of commercially available nonionic surfactant, 2 g of caustic soda, and 5 g of No. 3 silicate soda.
g was added and disintegrated using a kneader for 15 minutes at a pulp concentration of 15% and a temperature of 50℃, and the mixture was kept at 60℃ for 1 hour, and then a slurry of 10% was prepared at a pulp concentration of 1% and a temperature of 20℃. did. 7.5 of them (pulp amount
75g) was collected and subjected to flotation treatment for 10 minutes using a test floatator (manufactured by Kyokuto Shinko Co., Ltd.) to remove floating floss, and dehydrated to a pulp concentration of 15% using an 80mesh sieve. A pulp amount of 52.3g was obtained. This stock was hand-sheeted using a TAPPI sheet machine, and the evaluation of deinking was conducted in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 2 The following was the same as Comparative Example 1, using 100% recycled newspaper as the raw material. Comparative Example 3 The same treatment as in Comparative Example 1 was carried out using 50% recycled paper, 30% copied paper from Canon PC20, and 20% printed paper from IBM3800 as raw materials.

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Claims (1)

[Claims] 1 Waste paper is disintegrated, an aromatic hydrocarbon compound and/or a chlorinated product thereof having a melting point higher than room temperature is added thereto, and the temperature of the pulp slurry is adjusted to A solid substance containing an aromatic hydrocarbon compound and/or a chlorinated compound containing an ink component or a toner component is extracted from a pulp slurry by heating the chlorinated compound above its melting point and then cooling it below its melting point. remove the pulp slurry, add adsorbent to the pulp slurry,
A method for recycling used paper, which comprises removing from pulp slurry an adsorbent that has adsorbed residual aromatic hydrocarbon compounds and/or their chlorinated products by heating and cooling. 2 Disintegrate waste paper, add an aromatic hydrocarbon compound and/or chlorinated product thereof having a melting point higher than room temperature, and adjust the temperature of the pulp slurry to the temperature of the aromatic hydrocarbon compound and/or chlorinated product. By heating above the melting point and then cooling below the melting point, solids containing ink components and toner components in aromatic hydrocarbon compounds and/or their chlorinated products are removed from the pulp slurry. Add adsorbent to
In a waste paper recycling method that involves removing an adsorbent that adsorbs residual aromatic hydrocarbon compounds and/or their chlorinated substances from pulp slurry by heating and cooling, the removed ink components and The aromatic hydrocarbon compound and/or the chlorinated substance containing the toner component and the adsorbent adsorbing the aromatic hydrocarbon compound and/or the chlorinated substance are distilled or heated. A method for recycling used paper, which comprises recycling and using hydrocarbon compounds and/or their chlorinated products and adsorbents. 3 Aromatic hydrocarbon compounds and/or their chlorinated substances have a solubility parameter of 7.0 to 12.0
A method for recycling waste paper as set forth in claim 1 or 2, which falls within the scope of claim 1 or 2. 4. The aromatic hydrocarbon compound and/or its chlorinated compound is a single substance or a mixture having a melting point of 25°C to 100°C, as described in any one of claims 1 to 3. How to recycle used paper. 5. Claims 1, 3, or 5, in which the aromatic hydrocarbon compound and/or its chlorinated compound is a single substance or a mixture that does not dissolve 0.04 g or more in the aqueous solution 1 in the temperature range of 25°C to 100°C. The waste paper recycling method described in Section 4. 6. Any one of claims 1 to 5, where the adsorbent is a solid that has the property of dissolving or swelling with the aromatic hydrocarbon compound and/or its chlorinated compound used. Described method for recycling used paper.