JP3051341B2 - Deinking agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deinking agent used for recycling used paper such as coated paper and newsprint. More specifically, the present invention relates to a deinking agent capable of obtaining a deinked pulp having high whiteness and a small number of residual inks when performing deinking treatment on coated paper or newsprint by a flotation method.

[0002]

2. Description of the Related Art Recycling of newspapers, magazines, etc. has been practiced for a long time, but recently effective use of pulp resources has become increasingly important from the viewpoints of shortage of pulp resources, soaring prices, measures against garbage, and protection of forest resources. It is taking on sex. The development of advanced utilization technology of deinked pulp has been spurred to meet the growing needs. On the other hand, recently used paper has become more steep in terms of deinking due to changes in printing ink components.

[0003] In order to further promote deinking, improvements have been made to devices. For example, a high-concentration aging treatment by installing a tower, the introduction of a disperser and a kneader for further promoting the ink peeling by physical force, and the installation of a high-concentration pulverizing pulper can be mentioned. Also in the case of floaters, the introduction of high-bubble type floaters has become active. And in such a method, in order to separate and remove ink and other impurities from waste paper,
Various drugs and deinking agents are used in combination. Specifically, alkaline agents such as sodium hydroxide, sodium silicate, sodium carbonate and sodium phosphate, hydrogen peroxide, hyposulfite, bleaching agents such as hypochlorite, EDTA,
Agents such as sequestrants such as DTPA and deinking agents such as alkylbenzene sulfonates, higher alcohol sulfates, α-olefin sulfonates, anionic activators such as dialkyl sulfosuccinates, higher alcohols, alkylphenols and fatty acids Nonionic activators such as ethylene oxide adducts and alkanolamides have been used alone or in combination of two or more.

However, when attention is paid to deinking agents, these deinking agents have a large bubble property in flotation treatment, but have poor bubble stability, a low ink collecting ability, and a detergency. Because its washing power is weak,
Only low quality deinked pulp was obtained. For example, even if a high whiteness is obtained, there is dullness, and there is no choice but to limit the use of deinked pulp (reduce the amount of paperboard used below and below, and reduce the amount of paperboard used in newspapers). there were.

As an improved technique, a deinking agent containing, as an active ingredient, a reaction product of a specific OH-containing compound modified with ethylene oxide or alkylene oxide and a polyvalent carboxylic acid or its anhydride (JP-A-4-202881).
A deinking agent using an ester mixture obtained by adding ethylene oxide and propylene oxide at a specific ratio to a mixture of oil or fat or a product obtained by previously reacting the oil or fat with glycerin and a 1 to 14-valent alcohol (Japanese Patent Laid-Open No. -35289
No. 1) is disclosed.

[0006]

However, in recent years, in a deinking plant using a kneader or a disperser, the particle size of the dispersed ink often becomes fine due to the mechanical force applied at the time of peeling, and the ink is removed in the flotation step. However, the techniques disclosed in JP-A-4-202881 and JP-A-4-352891 are still unsatisfactory in removing ink, and a deinking agent that removes release ink more efficiently is desired. It is rare.

[0007]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the average degree of polymerization was 5%.
It has been found that the use of a deinking agent containing 0 to 2000 specific modified polyvinyl alcohol-based resin as an active ingredient makes it possible to remove the release ink more efficiently and to obtain a pulp having a high whiteness. It has arrived.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
Specific modified polyvinyl alcohol used in the present invention
Examples of the resin include a copolymer obtained by copolymerizing a specific ethylenically unsaturated monomer copolymerizable with vinyl acetate and saponifying the same or polyvinyl alcohol (hereinafter abbreviated as PVA).
It is) include those modified after a specific a.

[0009] Such a specific copolymerizable with vinyl acetate.
Acrylic acid, methacrylic acid, etc.
Luic acid, crotonic acid, maleic acid, maleic anhydride, ita
Carboxylic acids such as conic acid or its salts or mono- or
Is dialkyl ester, etc., ethylene sulfonic acid, allyl
Olefins such as sulfonic acid and methallyl sulfonic acid
Honic acid or a salt thereof, 2-acrylamide-2-methyl
Polyoxyalkylene (meth) allyl ether such as lepropanesulfonic acid or a salt thereof , polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether, polyoxyethylene (meth)
Acrylates, polyoxyalkylene (meth) acrylates such as polyoxypropylene (meth) acrylate,
Polyoxyalkylene (meth) acrylamide such as polyoxyethylene (meth) acrylamide and polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether,
Examples thereof include polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, and polyoxypropylene vinylamine.

Carboxylic acid-modified PVA which is a saponified copolymer of a carboxylic acid group-containing monomer and a (poly) oxyalkylene group-containing monomer represented by the following formula

Embedded image [However, R ¹ and R ² are hydrogen or an alkyl group, X is hydrogen, an organic residue such as an alkyl group, an alkyl ester group, an alkyl ether group, an alkyl amide group, a sulfonate group, and the condensation degree n is an integer of 1 to 300. (Poly) oxyalkylene group-modified PVA which is a saponified copolymer of
Is, the degree of condensation of such polyoxyalkylene 1 to 30
0, especially 4 to 50, is suitable, and the degree of modification of each is 0.1 to 10 mol%, preferably 0.5 to 5 mol%.

As a method of post-modification, a method in which polyvinyl alcohol is oxyalkylenated may be mentioned. The average degree of polymerization of the PVA resin used in the present invention is 50.
When the average degree of polymerization is less than 50, sufficient surface activity cannot be obtained. On the other hand, when the average polymerization degree exceeds 2,000, the viscosity becomes high and the handling becomes difficult and unsuitable.

The types of used paper to be deinked in the present invention include newsprint, coated paper, corrugated cardboard, and the like, and are preferably newsprint and medium quality paper.

Next, a deinking treatment method using the deinking agent of the present invention will be specifically described. Such deinking methods include:
A known method can be employed. As a method for adding the deinking agent, any of the waste paper dissolving step, the kneading step, the aging tower step and the flotation may be added to each of the respective steps or may be separately added to the waste paper dissolving step. Is most effective when it is added, and the method will be specifically described.

In an aqueous solution containing 0.1 to 0.5% by weight of sodium hydroxide and 0.1 to 0.35% by weight of a deinking agent based on pulp, waste paper is prepared by pulp concentration of 5 to 20% by weight, preferably 10 to 10% by weight. -15% by weight of the aqueous dispersion,
Stir at 0-50 ° C. for 10-20 minutes. Next, the aqueous dispersion is filtered with a filter and a centrifuge to have a pulp concentration of 25 to 30% by weight.
Dehydrate until it is. Then abrasives (sodium hydroxide, sodium silicate, sodium sulfite, sodium phosphate)
And a bleaching agent (hydrogen peroxide solution, sodium hypochlorite, sodium hyposulfite) are added, and the mixture is stirred at 55 ° C. for 2 hours. Further, water is added so that the pulp concentration becomes 1% by weight, and the calcium chloride is stirred at 10 to 50 ° C. for 5 to 60 minutes. The pulp concentration is adjusted to a solid content concentration of 0.1 to 10% by weight. Abrasives and bleaching agents may be charged together with the deinking agent.

[0015]

The present invention will be specifically described below with reference to examples. In the examples, “%” is based on weight unless otherwise specified. Examples 1 to 6 Collected used newspaper collected in the market Shredded newspaper was cut into 2 x 5 cm pieces, and a certain amount was put into a table disintegrator, in which water and sodium hydroxide were 1.0% (relative to pulp) and silica. Sodium 3.0% (relative to pulp), 30% hydrogen peroxide solution 3.0% (relative to pulp), and various modified PVA resins shown in Table 1 are reduced to 0.4% (relative to pulp). Pulp concentration of 5
%, At 55 ° C for 20 minutes, and then aged at 50 ° C for 60 minutes. Thereafter, water was added to dilute the pulp concentration to 1.0%, and calcium chloride was added to 1.0%,
A flotation treatment was performed at 30 ° C. for 10 minutes. After the pulp slurry after flotation was concentrated to a concentration of 6%, water was added to dilute it to about 1%, and a pulp sheet was prepared using a TAPPI sheet machine. Using the obtained pulp sheet, the whiteness, the total number of inks, the foam height, and the ink collecting power were measured as follows.

(Whiteness) Measured by a Hunter color difference meter. (Total number of inks) Measured with an image analyzer (× 100). (Foam powder height) The amount of foam scraped out from the laboratory floatator for 3 minutes was measured with a 2 liter cylinder. (Ink Collecting Power) The ink collecting power was calculated by the following equation. The area of the ink was measured with an image analysis processor. Ink collecting force = [(ba) / b] × 100 a: Area of remaining ink (after flotation) b: Area of ink (before flotation)

Comparative Example 1 The same procedure as in Example 1 was carried out except that the unmodified PVA resin shown in Table 1 was used instead of the modified PVA resin. Comparative Example 2 In place of the modified PVA in Example 1, 57 l of a compound obtained by block addition of 29 mol of ethylene oxide (EO) and 10 mol of propylene oxide (PO) to 12-hydroxystearic acid and 29.2 g of succinic anhydride were added in 1 l. , The reaction temperature is 100 ° C., and the stirring speed is 400r.
The reaction was carried out in the same manner except that the same amount of the EO / PO adduct of 12-hydroxystearic acid obtained by reacting at pm in a nitrogen atmosphere was used.

COMPARATIVE EXAMPLE 3 Instead of the modified PVA in Example 1, coconut oil / glycerin (1 / 0.6 molar ratio) and ethylene oxide (EO) 45 were used.
1 g of 350 g of a compound obtained by block addition of 23 mol of propylene oxide (PO) and 9.5 g of succinic anhydride.
At a reaction temperature of 100 ° C. and a stirring speed of 40.
The same procedure was performed except that the same amount of coconut oil / glycerin EO / PO adduct obtained by reacting at 0 rpm under a nitrogen atmosphere was used.

Comparative Example 4 Example 1 was repeated except that the same amount of ammonium stearate was used instead of the modified PVA.

Comparative Example 5 The same procedure was performed as in Example 1 except that the same amount of sodium dodecylbenzenesulfonate was used instead of the modified PVA.

Table 2 shows the measurement results of the examples and comparative examples.

TABLE 1 Degree of saponification of modified PVA resin Resin degree of polymerization Modified species (mol%) (mol%, degree of condensation *) Example 1 90 600 Polyoxyethylene (2 mol%, n = 5) Example 2 88 1200 Poly Oxyethylene (1 mol%, n = 13) Example 3 80 700 Polyoxypropylene (0.5 mol%, n = 18) Example 4 88 1000 Polyoxypropylene (1 mol%, n = 3) Example 5 97 1800 Maleic acid (3 mol%) Example 6 91 600 Maleic acid (1 mol%) Comparative Example 1 88 500 --- *: n represents the condensation degree of the following formula. [However, R ¹ and R ² are hydrogen or an alkyl group, X is hydrogen, an organic residue such as an alkyl group, an alkyl ester group, an alkylamide group, a sulfonate group, etc.]

[0022]

Table 2 Whiteness Total number of remaining inks Bubble amount (ml) Ink collecting power (%) (cm / 2 min) (%) Example 1 57 38 490 90 Example 2 60 50 380 96 Example 3 63 39 470 92 Example 4 66 37 370 90 Example 5 59 46 390 89 Example 6 55 32 290 95 Comparative Example 1 65 37 350 89 Comparative Example 2 45 50 430 85 Comparative Example 3 40 60 600 600 82 Comparative Example 4 50 70 400 72 Comparative Example 5 40 55 650 80

[0023]

The deinking agent of the present invention has an average degree of polymerization of 50 to 50.
Since 2000 specific modified PVA resin is used as an active ingredient, it is possible to obtain deinked pulp with an appropriate bubble height during deinking, high ink collecting power, high whiteness, and a small number of remaining inks. Can be.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D21C 5/02

Claims (4)

(57) [Claims] 1. A modified polyvinyl alcohol having an average degree of polymerization of 50 to 2,000.
A (poly) oxyl resin,
Sialkylene modified polyvinyl alcohol, carboxylic acid modified
Polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol
Modified polyvinyl alcohol resin selected from
A deinking agent characterized by being an active ingredient. 2. The paper to be deinked is coated paper or newspaper.
The deinking agent according to claim 1, characterized in that: 3. The amount used at the time of deinking treatment is based on pulp.
2. The composition according to claim 1, wherein the content is 0.1 to 10% by weight.
Or the deinking agent according to 2. 4. A method for performing a deinking process by a floatation method.
The deinking according to any one of claims 1 to 3, wherein
Agent.