JPH04333683A - Preparation of pulp suspension for papermaking of recording paper - Google Patents

Abstract

PURPOSE:To prepare damaged or waste paper of recording paper into a pulp suspension for papermaking without performing recycle pulping or recovery of the pulp. CONSTITUTION:The subject method is characterized in that a pigment having >=8m<2> BET specific surface area and a compound having active chlorine or oxygen are added to a pulp suspension in or after macerating recording paper using a basic dye and a colorant.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for disintegrating recording paper to prepare a pulp suspension for papermaking.

0002

[Prior Art] Pressure-sensitive copying paper, heat-sensitive recording paper, etc. are available as recording paper made by using a basic dye and a coloring agent on a sheet made of pulp fibers, but recently, especially with the development of fax machines, Demand for thermal recording paper is increasing markedly. Thermosensitive recording paper is composed of fine particles of a basic colorless dye, a coloring agent, a sensitizer, a pigment, a binder, an auxiliary agent, and the like. Images recorded on this thermosensitive recording paper are generally inferior in water resistance, oil resistance, plasticizer resistance, and the like. For this reason, for example, if water is added to a colored image,
If it comes into contact with oil or plasticizers contained in plastic films, the image density will drop significantly. Furthermore, it has the disadvantage that when the heat-sensitive recording layer is touched during handling, a fingerprint-like fog is generated. In order to solve these problems, for example, thermal recording paper in which a protective layer is provided by coating an aqueous emulsion, a water-soluble polymer compound, etc. on a thermal recording layer is widely used in the field of thermal labels.

On the other hand, as the production of thermal recording paper increases, the generation of waste paper and waste paper of thermal recording paper also increases.
Therefore, the development of a recycled pulping method for recovering and reusing pulp from waste paper and waste paper has become a new issue.

[0004] Conventionally, in paper factories, the pulp of waste paper and waste paper such as newsprint and coated paper for printing has been collected and reused. For example, Tokuko Sho 50-290
No. 42 describes a method for obtaining recycled pulp from waste paper and waste paper of coated printing paper (disintegration process, rough selection process, dehydration process, bleaching process,
(consisting of a floating separation process) has been proposed, and was published in Japanese Patent Application Laid-Open No.
No. 6802 also proposes a method of disintegration using an alkaline solution containing a surfactant.

However, when these methods are applied to obtain recycled pulp from waste or waste paper of thermal recording paper, dyes, coloring agents, sensitizers, and A large amount of water is required to separate and remove the binder, etc.

Furthermore, when obtaining recycled pulp from waste heat-sensitive recording paper or waste paper, high carbon fiber containing a large amount of difficult to decompose substances is used.
OD (low BOD) white water is generated. When such white water is discharged by a method such as biological treatment (for example, activated sludge), a large amount of cost and equipment are required as shown below.

On the other hand, in order to avoid the above-mentioned problems, the thermal recording paper is simply disintegrated without converting the waste paper or used paper of the thermal recording paper into recycled pulp or recovering the pulp, and the disintegrated pulp is processed as it is, for example, into virgin pulp. Attempts to make paper by mixing these materials have also been considered. However, this method has the following problems. That is,

[0008] ■ The dye, coloring agent, sensitizer, binder, auxiliary agent, etc. that make up the heat-sensitive recording layer circulate in the machine system, causing a lot of white water foaming, and if paper is made as it is, the voids of the bubbles will appear on the paper surface. In addition, lipophilic substances are separated from the water and dirt is generated and accumulated in the machine system (wires, inside piping, canvas, etc.), and this is the cause. Therefore, there is a problem that paper runs out easily.

■ When high COD white water containing the above-mentioned persistent substances is discharged from the inside of the machine system to the outside of the machine system, when it is treated with activated sludge, the COD is transferred to biological treatment.
The load becomes high, and therefore, for example, it is necessary to increase the capacity of the aeration tank, reduce the processing flow rate, etc. In particular, the white water that flows out when mixing waste paper of thermosensitive recording paper or disintegrated pulp of waste paper is typically high COD (low BOD), so the activated sludge treatment also requires significant changes.

[0010] The present inventors have proposed a preparation method that improves the above-mentioned problems when paper is made by simply disintegrating the heat-sensitive recording paper or pressure-sensitive copying paper and mixing the disintegrated pulp as it is, for example, with virgin pulp. After careful consideration,
The following invention has been completed.

[0011]

SUMMARY OF THE INVENTION The present invention provides a method for preparing a pulp suspension for making paper by simply disintegrating recording paper and mixing the disintegrated pulp as it is, for example, with virgin pulp.
Especially low COD in high COD white water containing large amounts of persistent substances.
In addition to suppressing the foaming of white water circulating in the machine system during paper making, it prevents the formation of stains in the machine system (wires, inside piping, canvas, etc.) due to the separation of lipophilic substances from the water. The purpose of this invention is to provide a method for preparing a disintegrated pulp suspension for recording paper, which prevents paper breakage during paper making and ensures machine operability by suppressing the accumulation of pulp. .

0012

[Means for Solving the Problems] The present invention provides a method for disintegrating recording paper using a basic dye and a coloring agent to prepare a pulp suspension for papermaking. A pulp suspension for making recording paper, characterized in that a pigment having a BET specific surface area of 8 m2/g or more and a compound having active chlorine or active oxygen are added to the pulp suspension after time or disintegration. This is a preparation method.

[0013]

[Means] In the present invention, the recording paper to which the disintegrated pulp suspension preparation method is applied is a recording paper made using a basic dye and a coloring agent, and is mainly used for pressure-sensitive copying paper and heat-sensitive recording paper. Damaged paper is waste paper.

The present invention requires that a pigment having a BET specific surface area of 8 m2/g or more be added to the pulp suspension during or after disintegration of the recording paper. The aim is to make the pigment adsorb dyes, coloring agents, binders, auxiliary agents, etc. that are separated during or after the disintegration of the recording paper. In fact, the above-mentioned pigments have the function of efficiently adsorbing dyes, coloring agents, binders, auxiliaries, etc. constituting recording paper in the presence of compounds containing active chlorine or active oxygen, which will be described later.

Pigments that can be used for this purpose include bentonite, montmorillonite, sericite,
Pigments with a layered structure such as halloysite, saponite, activated clay, zeolite, diatomaceous earth, etc., and organic modified products thereof (for example, pigments with organic substances such as wax and surfactants coated or adsorbed on the pigment surface), Examples include finely powdered silicic acid and organic modified products thereof, aluminum silicate, calcium silicate, white carbon, magnesium carbonate, and synthetic inorganic porous materials.

The present invention is not limited to these pigments, but any pigment having a BET specific surface area of 8 m2/g or more can be used. Among these, pigments with a layered structure such as bentonite, montmorillonite, activated clay, zeolite, diatomaceous earth, and organic modified products thereof are particularly preferred in terms of effectiveness.

[0017] The amount of pigment with a BET specific surface area of 8 m2/g or more suppresses the foaming of white water circulating within the machine system, and prevents wires and piping within the machine system by separating lipophilic substances from the water. Suppresses the generation and accumulation of dirt (interior, canvas, etc.), lowers the COD of wastewater,
Although it is determined as appropriate in consideration of freeness, cost, etc., the amount is 1 to 50 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of recording paper. Incidentally, if the amount is less than 1 part by weight, the desired effect cannot be obtained. In addition, if the amount exceeds 50 parts by weight, the pigment particles will too strengthen the binding and aggregation of pulp fibers during the paper-making stage, resulting in a change in freeness (reduction in water retention) when paper is made on a wire. A withering phenomenon occurs, resulting in paper breakage and deterioration of the paper's consistency.

The present invention further requires that a compound containing active chlorine or active oxygen be added to the pulp suspension during or after disintegration of the recording paper; Alternatively, the aim is to prevent foaming from occurring due to the binder separated after disintegration, and to promote the adsorption efficiency of the dye, coloring agent, binder, auxiliary agent, etc. separated by disintegration to the pigment. That is.

[0019] The present inventors have investigated various effective substances that meet the above purpose, and found that compounds having active chlorine include NaClO, CaClO, HClO,
ClO2 or Cl2 is suitable, and compounds with active oxygen include H2O2, O3, Na2O2
, or (NH4)2S2O8 was confirmed to be suitable for the purpose.

Incidentally, the reason why the above-mentioned substance is suitably suited for the purpose is probably that by adding it during or after disaggregation of the recording paper, active chlorine or active oxygen can be
Among the dyes, coloring agents, binders, auxiliaries, etc. separated by the disintegration of the recording paper, the binders that cause foaming are oxidized and decomposed to reduce their molecular weight to suppress foaming and to reduce their molecular weight. The substance, along with other substances that cause high COD, has a BET specific surface area of 8 m2/
It is presumed that it plays a role in further promoting adsorption to pigments with a weight of more than 100 g.

[0021]The binder, dye, coloring agent,
Auxiliary agents are high COD components, and by promoting their decomposition or adsorption to pigments, it is possible to reduce the COD of white water discharged outside the machine, and it is possible to use biological treatment such as activated sludge treatment. As a result, COD can be cut under conventional biological treatment operating conditions without causing an increase in COD load.

In particular, most of the recording papers currently on the market use polyvalent metal salts of aromatic carboxylic acids or phenol compounds as coloring agents. However,
These compounds act as toxic substances for activated sludge, and if a large amount of highly concentrated raw water flows into the activated sludge, they will cause bacteria to become inactivated or killed. However, according to the present invention, the color former is reduced in molecular weight by the action of active chlorine or active oxygen as an oxidizing agent, and as a result, the color former compound in the white water and pulp disappears. Therefore, in activated sludge treatment of wastewater, it is possible to avoid inactivation or killing of bacteria, and it is possible to maintain the efficiency of activated sludge treatment.

[0023] Among the above-mentioned compounds having active chlorine or compounds having active oxygen, NaClO, C
aClO, HClO, Cl2, etc. are excellent in terms of effectiveness. The amount of this compound containing active chlorine or active oxygen added is 0 in terms of effective chlorine per 100 parts by weight of recording paper.
．． The amount is 1 to 10 parts by weight, preferably 0.5 to 8 parts by weight. Incidentally, if the amount is less than 0.5 parts by weight, the desired effect cannot be obtained. Moreover, if it exceeds 10 parts by weight, it may cause deterioration of the pulp, corrosiveness of equipment in the machine system, and excessive cohesion of pulp fibers due to the increase in ions of the above-mentioned additives.

[0024] As described above, the present invention provides a pulp suspension having a BET specific surface area of 8 m2 during or after disintegrating the recording paper.
The present invention is characterized by adding a pigment having an amount of at least /g or more and a compound having active chlorine or active oxygen, but the expected effects of the present invention cannot be obtained with either one alone. In other words, the present invention is characterized by utilizing the synergistic effect of both substances.

[0025] In the present invention, when pigments having a BET specific surface area of 8 m2/g or more are added to the pulp suspension during or after disintegration of recording paper, among them, bentonite, montmorillonite, activated clay, zeolite, diatomaceous earth, etc. It has been described that pigments with a layered structure such as and organic modified products thereof are particularly preferable in terms of effects, but these pigments are substances that cause a coloring reaction with basic dyes that separate when the recording paper disintegrates. . Therefore, if a pulp suspension containing a pigment with the dye adsorbed thereon is made into paper as it is, the resulting paper will naturally be colored. However, in the present invention, in addition to the pigment, a compound having active chlorine or a compound having active oxygen is used in combination, as described above.
Possibly because structural changes in the dyes (for example, loss of substituents, etc.) occur, resulting in a change in color tone, there is little decrease in whiteness when the virgin pulp is blended into paper.

[0026] In preparing the pulp suspension of the present invention, there are no particular limitations on the pH, temperature, addition method, etc. In addition, when paper-making a pulp containing the pulp suspension obtained by the present invention, it goes without saying that known paper-making methods can be applied as they are. Furthermore, it goes without saying that the paper base paper can be used for high-quality paper, coated paper for printing, recording paper, etc.

[0027]

EXAMPLES Examples will be described below, but it goes without saying that the present invention is not limited only to these examples. In addition,
In the examples, "%" and "parts" refer to "% by weight" and "parts by weight" unless otherwise specified.

Example 1 Low concentration pulper (manufactured by Mitsubishi Heavy Industries, product name: “High,”
6900 liters of water in "Low pulper" 8M3 capacity)
After that, 60 kg of sodium bentonite (manufactured by Kunimine Kogyo Co., Ltd., trade name "Kunigel 3V") having a BET specific surface area of 10 m2/g was added and dispersed.

After that, 600 kg of waste heat-sensitive recording paper generated during the manufacturing process of heat-sensitive recording paper (using a phenol compound as a coloring agent, a fluoran dye as a dye, and polyvinyl alcohol as a binder) was added. ,
This was disintegrated to form pulp. When in a semi-disaggregated state, sodium hypochlorite containing 6% available chlorine was added to 100 parts by weight of broken heat-sensitive recording paper in an amount of 5% in terms of available chlorine. After aging for 1 hour, a disintegrated pulp suspension having a concentration of 8% was obtained.

The obtained disintegrated pulp suspension was adjusted to a concentration of 4.5%, and was mixed with a high concentration cleaner [Aikawa Tekko Co., Ltd.].
Foreign matter was removed using a "Staff Cleaner (Type B)" manufactured by Aikawa Co., Ltd. and a high-density screen (Model 300, manufactured by Aikawa-Ramo), and then refined to a freeness of 450 cc using a double disc refiner (manufactured by Aikawa Tekko Co., Ltd.). It was adjusted.

The disintegrated pulp suspension thus obtained (10 parts by weight in terms of solid content) was mixed with hardwood that had been beaten to a freeness of 500 cc (=90 parts by weight of LKP in terms of solid content). Then, 0.7 parts by weight of "KW-677" manufactured by Arakawa Chemical Industry Co., Ltd. as a paper strength enhancer was added to this.
As a sizing agent, the product name “SPK” manufactured by Arakawa Chemical Industry Co., Ltd.
A pulp suspension for paper making was prepared by adding 0.1 part by weight of "-902" and 0.05 part by weight of "Percoll 155" manufactured by Allied Colloid Co., Ltd.

[0032] Using this pulp suspension for paper making, dry basis weight was 100 using a Fourdrinier multi-tube cylinder dryer paper machine.
A base paper of g/m2 was made. The foaming state of white water generated during paper making was visually evaluated. See Table 1 for evaluation results.
Described in . Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. The evaluation results are listed in Table-1. In addition, the filtrate after recovering the pulp from the above white water by pressure flotation etc. is JIS K 010
When the COD value was measured based on the 2 method, it was 200 PP.
It was M.

[0033] Furthermore, when the pulp content is recovered from this white water by pressurized flotation, etc., the remaining liquid is treated with activated sludge, and the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case where the waste paper of the thermal recording paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness of the paper (drying at 120°C for 10 minutes) was measured with a Hunter whiteness meter and was 78%, indicating that the whiteness of paper made of 100% LKP, which does not contain any pulp obtained by disintegrating the waste paper of thermal recording paper, is 78%. There was no significant difference compared to 81%.

Example 2 In Example 1, instead of 60 kg of sodium bentonite, the BET specific surface area (N2 gas method) was 100 to 15.
120 kg of 0m2/g ultrafine powdered silicic acid (manufactured by Mizusawa Chemical Industry Co., Ltd., trade name "Mizukasil P-801")
A disintegrated pulp suspension of heat-sensitive recording paper waste was prepared in the same manner as in Example 1, except that H202 (8% effective chlorine equivalent) was used instead of sodium hypochlorite, and Paper disintegrated pulp suspension (20 parts by weight in terms of solid content),
Hardwood that has been beaten to a freeness of 500cc (=LK
A pulp suspension for papermaking was prepared in the same manner as in Example 1, except that 80 parts by weight of P (calculated as solid content) was mixed.

[0035] Using this pulp suspension for paper making, dry basis weight was 100 using a Fourdrinier multi-tube type cylinder dryer paper machine.
A base paper of g/m2 was made. The foaming state of white water generated during paper making was visually evaluated. See Table 1 for evaluation results.
Described in . Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. The evaluation results are listed in Table-1. In addition, the filtrate after recovering the pulp from the above white water by pressure flotation etc. is JIS K 010
When the COD value was measured based on the 2 method, it was 210 PP.
It was M.

[0036] Furthermore, when the pulp content is recovered from this white water by pressurized flotation, etc., the remaining liquid is treated with activated sludge, and the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case where the waste paper of the thermal recording paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness of the paper (drying at 120°C for 10 minutes) was measured with a Hunter whiteness meter and was 78%, indicating that the whiteness of paper made of 100% LKP, which does not contain any pulp obtained by disintegrating the waste paper of thermal recording paper, is 78%. The whiteness was considerably lower than that of 81%.

Example 3 Instead of 600 kg of waste heat-sensitive recording paper, pressure-sensitive copying paper (
Disintegrated pulp suspension and paper were made in the same manner as in Example 1, except that 600 kg of waste paper manufactured by Kanzaki Paper Co., Ltd. under the trade name "KS Copy, including top paper, middle paper, and bottom paper" was used. A pulp suspension was prepared.

[0038] Using this pulp suspension for paper making, dry basis weight was 100 using a fourdrinier multi-tube cylinder dryer paper machine.
A base paper of g/m2 was made. The foaming state of white water generated during paper making was visually evaluated. See Table 1 for evaluation results.
Described in . Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. The evaluation results are listed in Table-1. In addition, the filtrate after recovering the pulp from the above white water by pressure flotation etc. is JIS K 010
When the COD value was measured based on the 2 method, it was 150 PP.
It was M.

[0039] Furthermore, when the pulp content is recovered from this white water by pressure flotation, etc., the remaining liquid is treated with activated sludge, and the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case in which the waste paper of pressure-sensitive copying paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness (drying at 120° C. for 10 minutes) was measured using a Hunter whiteness meter and was found to be 80%.

Comparative Example 1 A disintegrated pulp suspension and a papermaking pulp suspension were prepared in the same manner as in Example 1, except that sodium bentonite with a BET specific surface area of 10 m2/g and sodium hypochlorite were not added. did.

[0041] Using this pulp suspension for paper making, dry basis weight was 100 using a Fourdrinier multi-tube cylinder dryer paper machine.
A base paper of g/m2 was made. The foaming state of white water generated during paper making was visually evaluated. See Table 1 for evaluation results.
Described in . Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. The evaluation results are listed in Table-1. In addition, the filtrate after recovering the pulp from the above white water by pressure flotation etc. is JIS K 010
When the COD value was measured based on the 2 method, it was 250 PP.
It was M.

[0042] Furthermore, when the remaining liquid is treated with activated sludge after the pulp is recovered from this white water by pressure flotation, etc., the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case where the waste paper of the thermal recording paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness (drying at 120° C. for 10 minutes) was measured using a Hunter whiteness meter and was found to be 80%.

Comparative Example 2 A disintegrated pulp suspension and a papermaking pulp suspension were prepared in the same manner as in Example 1, except that sodium hypochlorite was not added. Using this pulp suspension for paper making, dry basis weight was 100 g/m using a Fourdrinier multi-tube cylinder dryer paper machine.
2 base paper was made. The foaming state of white water generated during paper making was visually evaluated. The evaluation results are listed in Table 1. Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. Table 1 for evaluation results
Described in. Further, the COD value of the filtrate after recovering the pulp from the white water by pressurized flotation or the like was measured according to the JIS K 0102 method, and the COD value was 240 PPM.

[0044] Furthermore, when the remaining liquid is treated with activated sludge after the pulp is recovered from this white water by pressure flotation, etc., the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case where the waste paper of the thermal recording paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness (drying at 120° C. for 10 minutes) was measured using a Hunter whiteness meter and was found to be 79%.

Comparative Example 3 A disintegrated pulp suspension and a papermaking pulp suspension were prepared in the same manner as in Example 1, except that sodium bentonite having a BET specific surface area of 10 m 2 /g was not added. Using this pulp suspension for paper making, a base paper having a dry basis weight of 100 g/m2 was made using a fourdrinier cylinder dryer paper machine. The foaming state of white water generated during paper making was visually evaluated. The evaluation results are listed in Table 1. Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. The evaluation results are listed in Table-1. Further, the COD value of the filtrate after recovering the pulp from the white water by pressurized flotation or the like was measured according to the JIS K 0102 method, and the COD value was 245 PPM.

[0046] Furthermore, when the pulp content is recovered from this white water by pressure flotation, etc., the remaining liquid is treated with activated sludge, and the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case where the waste paper of the thermal recording paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness (drying at 120° C. for 10 minutes) was measured using a Hunter whiteness meter and was found to be 80%.

Comparative Example 4 In Example 1, 60 kg of talc was used instead of sodium bentonite with a BET specific surface area of 10 m2/g, and sodium hypochlorite with an available chlorine content of 6% was used on thermal recording paper. A disintegrated pulp suspension and a papermaking pulp suspension were prepared in the same manner as in Example 1, except that 5% of chlorine was added in terms of available chlorine based on 100 parts by weight of broken paper.

[0048] Using this pulp suspension for paper making, dry basis weight was 100 using a Fourdrinier multi-tube type cylinder dryer paper machine.
A base paper of g/m2 was made. The foaming state of white water generated during paper making was visually evaluated. See Table 1 for evaluation results.
Described in . Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. The evaluation results are listed in Table-1. In addition, the filtrate after recovering the pulp from the above white water by pressure flotation etc. is JIS K 010
When the COD value was measured based on the 2 method, it was 247 PP.
It was M.

[0049] Furthermore, when the pulp content is recovered from this white water by pressure flotation or the like, the remaining liquid is treated with activated sludge, and the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case where the waste paper of the thermal recording paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness (drying at 120° C. for 10 minutes) was measured using a Hunter whiteness meter and was found to be 79%.

Comparative Example 5 In Example 1, 60 kg of calcium carbonate "Albagros L" was used instead of sodium bentonite with a BET specific surface area of 10 m2/g, and hypochlorite with an available chlorine content of 6% was used. A disintegrated pulp suspension and a papermaking pulp suspension were prepared in the same manner as in Example 1, except that acid soda was added in an amount of 5% in terms of available chlorine based on 100 parts by weight of broken heat-sensitive recording paper.

[0051] Using this pulp suspension for paper making, dry basis weight was 100 using a Fourdrinier multi-tube cylinder dryer paper machine.
A base paper of g/m2 was made. The foaming state of white water generated during paper making was visually evaluated. See Table 1 for evaluation results.
Described in . Furthermore, the white water and the raw materials in the flow box were collected in a glass bottle, and the degree of stain on the wall of the glass bottle when it was turned upside down was visually evaluated. The evaluation results are listed in Table-1. In addition, the filtrate after recovering the pulp from the above white water by pressure flotation etc. is JIS K 010
When the COD value was measured based on the 2 method, it was 250 PP.
It was M.

[0052] In addition, when the pulp content is recovered from this white water by pressure flotation, etc., the remaining liquid is treated with activated sludge, and the CO
When the D-cut rate, sludge settling property, sludge activity, etc. were examined, no changes were observed at all compared to the case where the waste paper of the thermal recording paper was not mixed. Furthermore, the base paper obtained by papermaking (
The whiteness (drying at 120° C. for 10 minutes) was measured using a Hunter whiteness meter and was found to be 80%.

[0053]

[Table 1]

*Bubble generation status (visual observation of foaming status of white water generated during paper making). ◎・・・・・・ Almost no foaming. ○: Occurs slightly, but does not affect production. △... Quite a lot of bubbles are generated, and bubbles are observed on the paper. ×... This occurs very often, and troubles such as paper cuts occur frequently during paper making.

*Contamination condition (white water and raw materials in the flow box were collected in a glass bottle, and the degree of contamination on the wall of the glass bottle was visually evaluated when the bottle was turned upside down). ◎・・・・・・ Almost no stains. ○... Slightly dirty. △・・・・・・ Quite dirty ×・・・・・・ Very dirty.

*COD value (This is the value measured based on the JISK 0102 method of the filtrate after recovering the pulp by floating white water under pressure or the like).

*Hunter whiteness of the base paper (the higher the value, the higher the whiteness).

[0058]

According to the present invention, a pigment having a BET specific surface area of 8 m2/g or more and a compound having active chlorine or active oxygen are added to the pulp suspension during or after disintegration of recording paper. Because of this, high CO2 containing large amounts of difficult-to-decompose substances
D In addition to reducing the COD of white water, it also suppresses foaming of the white water that circulates within the machine system during paper making, and the separation of lipophilic substances from the water within the machine system (wires, inside piping, canvas, etc.) The occurrence of dirt and its accumulation can be suppressed, and as a result, paper breakage during paper making can be improved, and the machine operability can be ensured.

Claims (7)

[Claims] Claim 1: A method for preparing a pulp suspension for papermaking by disintegrating a recording paper using a basic dye and a coloring agent, the pulp suspension being used during or after disintegration of the recording paper. In liquid, BE
A method for preparing a pulp suspension for making recording paper, which comprises adding a pigment having a T specific surface area of 8 m2/g or more and a compound having active chlorine or active oxygen. 2. The method for preparing a pulp suspension according to claim 1, wherein the recording paper is a heat-sensitive recording paper. 3. The pigment having a BET specific surface area of 8 m2/g or more is bentonite, montmorillonite, kaolinite, sericite, halloysite, saponite, activated clay,
2. The method for preparing a pulp suspension according to claim 1, wherein the pigment is at least one selected from pigments such as zeolite, diatomaceous earth, ultrafine ground silicic acid, and synthetic inorganic porous materials. 4. The method for preparing a pulp suspension according to claim 1, wherein 1 to 100 parts by weight of a pigment having a BET specific surface area of 8 m2/g or more is added to 100 parts by weight of recording paper. . 5. The compound having active chlorine is NaClO,
The method for preparing a pulp suspension according to claim 1, characterized in that the suspension is CaClO, HClO, ClO2 or Cl2. 6. The compound having active oxygen is H2O2,
The method for preparing a pulp suspension according to claim 1, characterized in that the suspension is O3, Na2O2 or (NH4)2S2O8. 7. Preparation of the pulp suspension according to claim 1, wherein active chlorine or active oxygen is added in an amount of 0.1 to 10 parts by weight in terms of effective chlorine per 100 parts by weight of recording paper. Method.