GB2178079A - Deinking of waste paper - Google Patents

Abstract

In a method for deinking waste paper, the deinking of the waste paper is effected with a conventional deinking agent and an accelerator comprising a salt of a polymer selected from: (1) (meth)acrylic acid polymer, (2) maleic acid polymer, (3) a copolymer of (meth)acrylic acid and maleic acid, (4) a copolymer of (meth)acrylic acid (M1) and (meth)acrylic ester (M2), (5) a copolymer of maleic acid (M1) and (meth)acrylic ester (M2), and (6) a copolymer of (meth)acrylic acid (M1), maleic acid (M2) and (meth)acrylic ester (M2), the polymers (1), (2) and (3) each having an average molecular weight of 10,000 or less, the polymers (4), (5) and (6) each having a monomer ratio (M1/M2) of 1 to 49.

Description

SPECIFICATION Accelerator for disintegration in reclamation of waste paper The invention relates to an accelerator for disintegration in reclamation of waste paper. In particular it is useful to reclamation of waste woodfree paper. The accelerator is used with a deinking agent in deinking treatment (for example, flotation method, flotation-water washing method or water washing method) of waste woodfree paper such as waste simili, waste colored woodfree paper or waste dodger to give a deinked pulp having a high brightness and containing few large ink pieces and few residual ink particles.

Statement of prior arts The reclamation of waste woodfree paper such as waste simili, waste colored woodfree paper or waste dodger has long been carried out. Recently, the utilization of waste paper has become more important, because of the deficiency of resources of pulp and enhancement in the cost thereof. Further, the use of deinked pulp has enlarged toward high-quality products. On the other hand, current waste paper becomes more disadvantageous from the stand-point of deinking, because printing technology, printing system and printing ink composition have changed and waste paper which has never been reclaimed is now reclaimed. Therefore, improvements in an apparatus have been made for the purpose of acceleration of deinking.

Chemicals which have been employed for the separation and removal of impurities, such as ink or the like, from waste paper include alkalis such as sodium hydroxide, sodium silicate, sodium carbonate or sodium phosphate; bleaching agents such as hydrogen peroxide, hydrosulfite and hypochlorite; sequestering agents such as EDTA or DTPA and deinking agents such as anionic surfactants (for example, alkylbenzenesulfonate, higher alcohol sulfate, a-olefinsulfonate or dialkyl sulfosuccinate) and nonionic surfactants [for example, higher alcohols, alkylphenols, adducts of fatty acids with EO (ethylene oxide) or EO/PO (propylene oxide) or alkanolamides], each used alone or in admixture.

However, it is difficult to completely separate ink from waste paper and remove the separated ink by flotation and/or washing. Particularly, the removal of large ink pieces, that is, ones having a particle size of 100 to 4000 Fm is problematic. Further, coated paper (such as colored woodfree paper) is generally prepared by coating the surface of cellulose aggregat to impart necessary characteristics such as printability, gloss, surface strength or the like to the paper. For example, it is necessary for better printing that the voids among paper fibers are filled by coating to thereby decrease the number of points to which no ink adheres, thus attaining a beautiful and sharp printing effect. As understood from this printing effect, surface coating is a popular method for improving the surface characteristics of paper.The coating composition for such a purpose comprises an inorganic pigment such as clay, kaolin, calcium carbonate or titanium dioxide as a principal component and may contain a color pigment (for example, ultramarine, chrome yellow, lake, dye or metal powder), adhesive (for example, starch, casein, soybean protein, latex, acrylic resin or PVA), protein solubilizing agent (for example, ammonia, sodium carbonate, sodium hydroxide or boric acid), additive (for example, anti foaming agent or viscosity modifier), water-proofing agent (for example, urea resin, melamine-formaldehyde resin, hexamethylenetetramine resin, glyoxal, latex, formaldehyde or aluminum sulfate), finishing agent (for example, wax or soap), separating agent (for example, condensed phosphate) and the like. The content of each component is varied depending upon the required characteristics and operability.Printing ink is applied on the dry surface of the coating composition. When waste colored woodfree paper, waste dodger, waste simili or the like is subjected to deinking treatment, the coting layer, to which ink adheres, is presumed not to be disintegrated by the deinking agent of the prior arts, thus generating large ink drops. Up to this time, no effective means for preventing generation of large ink drops, that is, ones having a relatively large particle size of 100 to 4000 Fm, have been found as yet.

Summary of the invention The inventors of the present invention have investigated to overcome the above problems and have found that a deinked pulp having a high brightness and containing few large ink drops (having a particle size of 100 to 4000 Wm) can be obtained by using a disintegration accelerator for the reclamation of waste woodfree paper according to the present invention together with a deinking agent of the prior art.

On the basis of this finding, the present invention has been accomplished.

In a method for reclamation of waste paper, the invention provides an improvement in which the disintegration and deinking step is effected with a deinking agent and an accelerator comprising a salt of a polymer selected from: (1) (methy)acrylic acid polymer, (2) maleic acid polymer, (3) a copolymer of (meth)acrylic acid and maleic acid, (4) a copolymer of (mech)acrylic acid (M,) and (meth)acrylic ester (M2), (5) a copolymer of maleic acid (M,) and (meth)acrylic ester (M2), and (6) a copolymer of (meth)acrylic acid (M1), maleic acid (M2) and (meth)acrylic ester (M2). the polymers (1), (2) and (3) each having an average molecular weight of 10,000 or less, the polymers (4), (5) and (6) each having a monomer ratio (M,/M2) of 1 to 49.

The above defined invention includes two embodiment groups, one being directed to use of the polymer (1), (2) or (3), the other being drawn to use of the polymer (4), (5) or (6).

First one embodiment of (1) (2) or (3) polymers will be illustrated in detailed.

The present invention provides a disintegration accelerator for the reclamation of waste woodfree paper which comprises a salt of a (co)polymer of (meth)acrylic or/and maleic acid and having an average molecular weight of 10000 or below.

The salt of a (co)polymer according to the present invention must comprise acrylic (or meth-acrylic) or/ and maleic acid as a comonomer and must have a molecular weight of 10000 or below. The lower limit of the molecular weight is 200. Of course, the polymer of the present invention may contain various other monomers as the third component as long as the effect of the present invention is not adversely affected.

Representative examples of the salt of a (co)polymer according to the present invention are as follows: (I) Salt of polyacrylic or polymethacrylic acid having an average molecular weight of 1000 to 8000.

The salt may be one with alkali metal, ammonium or alkanolamine such as diethanolamine (DEA) or triethanolamine (TEA). The salt of polyacrylic or polymethacrylic acid may contain unneutralized units to such an extent as to have no adverse effect on the performance of the present invention. Further, the polymer of the present invention may contain other monomers as the second monomer to such an extent as to have no adverse effect on the performance of the present invention. Examples of the monomer to be used as the second monomer include acrylamide, various sulfonic acids such as methacrylsulfonic or vinylsulfonic acid, 2-hydroxyethyl acrylate, various acrylates, various methacrylates, N-methylolacrylamide and other copolymerizable monomers.

(II) Salt of polymaleic acid having an average molecular weight of 200 to 10000.

The average molecular weight is preferably 250 to 8000, still preferably 250 to 5000.

The salt of polymaleic acid can be easily prepared by a process which comprises polymerizing maleic an hydroxide and neutralizing the resulting polymer after ring opening or a process which comprises polymerizing maleic acid (salt). The salt of polymaleic acid may be one with alkali metal, ammonium, alkanolamine such as diethanolamine or triethanolamine. Further, the salt of polymaleic acid may contain unneutralized units to such an extent as to have no adverse effect on the performance of the present invention. Furthermore, the polymer of the present invention may contain other monomer as the second component to such an extent as to have no adverse effect on the performance of the present invention.

Examples of the monomer to be used as the second component include acrylamide, various sulfonic acids such as methacrylsulfonic or vinyl-sulfonic acid, 2-hydroxyethyl acrylate, various acrylates, various methacrylates, N-methylolacrylamide and other copolymerizable monomers.

Further, the monomer to be used as the second monomer may be a polyoxyalkylene monoallyl ether represented by the general formula:

wherein OR stands for an oxyalkylene group having 2 or 3 carbon atoms and n stands for a positive number of 1 to 50.

(ill) Salt of a copolymer comprising maleic acid (MA) and (meth)acrylic acid (AA) as essential monomers in a molar ratio (r) of MA to AA of 0.1 to 2.7 and having an average molecular weight (MW) of 1000 to 8000.

Among these salts, ones which satisfy the requirement that r is from 1.15 to 2.7, MW is from 1000 to 8000 and the value of r x MW is 3000 or above are most preferred. These salts are preferably prepared by copolymerizing (meth)acrylic acid with maleic acid in a molar ratio of 1 1.2 to 1 : 3.0 in the presence of a polymerization initiator in an aqueous medium maintained at a pH of 3.5 to 5.0 with an alkali metal hydroxide and neutralizing the resulting polymer. Of course, they can be prepared by other methods.

The salt of a copolymer of maleic acid with (meth)acrylic acid may be one with alkali metal, ammonium or alkanolamine such as diethanolamine or triethanolamine. Further, the salt of a copolymer may contain unneutralized units to such an extent as to have no adverse effect on the performance of the present invention.

Furthermore, the copolymer may contain other monomers as the third component. Examples of the monomer to be used as the third monomer include acrylamide, various sulfonic acids such as methacrylsulfonic or vinylsulfonic acid, 2-hydroxyethyl acrylate, various acrylates, various methacrylates, Nmethylolacrylamide and other copolymerizable monomers.

Particular preparative examples of the (co)polymer of the present invention will now be described (i) 200 g of deionized water was fed into a four-necked flask fitted with a stirrer, ia cooling tube, a thermometer, a nitrogen inlet tube and a dropping funnel. 162.1 g of 80% acrylic acid, 73.8 g of an adduct of acrylic acid with 4 to 5 mol of propylene oxide, 15.6 g of 2-mercaptoethanol and 4.56 g of ammonium persulfate were dropwise added to the flask in a nitrogen atmosphere. The content was stirred at 75"C for 1.5 hours. 48.6 g of 35% hydrogen peroxide was added to the flask. The resulting mixture was stirred at 75"C for 1.5 hours, aged at 80"C for 2 hours and neutralized with 105 g of 48% sodium hydroxide to obtain sodium salt of a copolymer.It had an average molecular weight (Mw) as measured by gel permeation chromatography (GPC) of about 3500. (ii) 670 g of deionized water was fed into a four-necked flask fitted with a stirrer, a cooling tube, a thermometer, a nitrogen gas inlet tube and a dropping funnel and heated to 100"C. 560 g of 80% acrylic acid, 492 g of 48% sodium hydroxide, 74 g of 30% ammonium persulfate and 132.8 g of 35% aqueous hydrogen peroxide were simultaneously added dropwise to the flask over a period of 4 hours. After the completion of the addition, the mixture was aged at 100"C for one hour to obtain sodium salt of polyacrylic acid. It had an average molecular weight as determined by GPC of about 5000.

The second embodiment will be below illustrated in detail.

The present invention provides a disintegration accelerator for the reclamation of waste woodfree paper which comprises a salt of a copolymer of (meth)-acrylic or/and maleic acid (M,) with (meth)acrylate (M2). The molar ratio, Sy, of M, to M2 of the disintegration accelerator may be from 1 to 49. When the (meth)acrylate (M2) is a compound represented by the general formula (I):

wherein R, stands for a hydrogen atom or a methyl group; R2 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; AO stands for an oxyalkylene group having 2 or 3 carbon atoms and n stands for a positive number of 1 to 50, a particularly excellent effect can be obtained.

The copolymer of the present invention has a molar ratio, Py, of M, to M2 of 1 to 49, preferably 4 to 19.

Further, the polymer has a molecular weight of 1000 to 10000, preferably 2500 to 8000. Of course, the polymer may contain other monomers as the third component as long as the effect of the present invention is not adversely affected.

A particular example of the preparation of the copolymer of the present invention will now be described.

200 g of deionized water was fed into a four-necked flask fitted with a stirrer, a cooling tube, a thermometer, a nitrogen inlet tube and a dropping funnel. 162.1 g of 80% acrylic acid, 147.6 g of an adduct of acrylic acid with 4 mol of propylene oxide, 15.6 g of 2-mercaptoethanol and 4.56 g of ammonium persulfate were dropwise added to the flask in a nitrogen atmosphere. The content was stirred at 75"C for 1.5 hours. 48.6 g of 35% hydrogen peroxide was added to the flask. The obtained mixture was stirred at 75C for 1.5 hours, aged at 80 C for 2 hours and neutralized with 105 g of 48% sodium hydroxide to obtain sodium salt of a copolymer.It had an average molecular weight (Mw) as determined by gel permeation chromatography(GPC) of about 4200. adducts of fatty acid with EO(ethylene oxide) or EO/PO(propylene oxide), higher fatty acid amides and amino oxides. Particularly, a nonionic surfactant is mainly used as a deinking agent for waste simili, waste colored woodfree paper or waste dodger.

The weight ratio of the disintegration accelerator of the present invention to the deinking agent of the prior art to be used in the deinking step is preferably between 1 10 and 10 1, still preferably between 1 3 and 3 :1.

The disintegration accelerator of the present invention is generally used together with a deinking agent. Though they may be added either in the disintegration step of waste paper or in a similar step, the addition step must be one where shear energy of a certain degree is applied.

The amount of the disintegration accelerator of the present invention to be added is preferably 0.05 to 2.0% by weight based on the waste paper or pulp.

When waste woodfree paper such as waste simili, waste colored woodfree paper or waste dodger is deinked by using a disintegration accelerator of the present invention together with a deinking agent, deinked pulp containing very few large ink drops (of a particle size of 100 to 4000 Fm) and very few residual ink drops can be obtained. Though the mechanism of the disintegration accelerator is not clear, it is presumed with respect to the flotation or flotation-water washing method that the disintegration accelerator might accelerate heteroaggreagation of released ink on air bubbles introduced in the flotation step to thereby prevent the ink from causing re-deposition on pulp.Further, it is presumed with respect to the water washing method that the disintegration accelerator might control the particle size of the ink to a suitable range where the deinking can be effectively carried out with a valveless filter, extractor or the like. These effects are presumed to be due to the ink dispersibility (a dispersibility of an extent not to hinder the hetero-aggregation between air bubble and ink) and protective-colloidal activity of the disintegration accelerator.

According to the present invention, the dis-integration accelerator for the reclamation of waste woodfree paper is generally used together with a deinking agent of the prior art. The deinking agent to be used in the present invention may be any anionic or mon ionic surfactant or any mixture thereof. Examples of the anionic surfactant include alkyl-benezenesulfonates, alkyl sulfates, polyoxyalkylene alkyl (or alkylaryl) sulfates, alkanesulfonates, a-olefinsulfonates and dialkyl sulfosuccinates. Examples of the nonionic surfactant include higher alcohols, alkylphenols, adducts of fatty acid with EO (ethylene oxide) or EO/PO (propylene oxide), higher fatty acid amides and amine oxides. Particularly, a nonionic surfactant is mainly used as a deinking agent for waste simili, waste colored woodfree paper or waste dodger.

The weight ratio of the disintegration accelerator of the present invention to the deinking agent of the prior art is preferably between 1:10 and 10 1, still preferably between 1: 3 and 3 1.

The disintegration accelerator of the present invention is generally used together with a deinking agent. Though they may be added either in the disintegration step of waste paper or in a similar step, the addition step must be one where shear energy of a certain degree is applied.

The amount of the disintegration accelerator of the present invention to be added is preferably 0.05 to 2.0% by weight based on the waste paper or pulp.

Example The present invention will now be described in more detail by Examples, but it is not limited-thereto.

In the following Examples, the resulting sheets were each examined for brightness with a color difference meter SM-3 (a product of Suga Shikenki Co., Ltd.) and for the number of residual ink drops (having a particle size of 100 or above) with an image analyzer Ruzex 500 (4X magnification; a product of Nippon Regulator Co., Ltd.) Example 1 Waste colored woodfree paper was cut into pieces of 2 x 5 cm and placed in a desk disintegrator.

Water, 1.0% (based on the raw material) of sodium hydroxide, 2.5% (based on the raw material) of sodium silicate, 5.0% (based on the raw material) of 30% hydrogen peroxide and 0.3% (based on the raw material) of a deinking agent were added to the disintegrator, followed by the addition of 0.3% (based on the raw material) of a disintegration accelerator. The disintegration was carried out a 50"C for 20 minutes with a pulp concentration of 5%. The mixture was aged at 50"C for 60 minutes and diluted with water to a pulp concentration of 1.0%. The diluted mixture was subjected to flotation at 30"C for 10 minutes. The resulting pulp slurry was concentrated to a concentration of 6% and diluted with water to a concentration of 1%. The slurry was treated with a TAPPI standard sheet machine to obtain a pulp sheet. The results are shown in Table 1.

TABLE 1 No. Delinking agent Disintegration accelerator for Brightness Number *2 Ro(EO)n(PO)mH*1 reclamation of waste woodree paper (%) of Molar ratio Mw residual R n m (Co)polymer (comonomer M1(M2) of comonomers ink drops r=M1/M2 1 C12H25 9 0 polysodium acrylate - 5000 80.1 48.8 2 C12H25 12 0 polysodium maleate - 300 80.8 40.0 Ex. 3 - - - polyTEA maleate - 500 81.2 35.5 4 C18H37 9 0 polysodium maleate/acrylate 1.0 7000 80.7 42.5 5 C18H37 20 15 polyammonium maleate/methacrylate 1.5 3500 80.0 49.2 6 C12H25 12 3 polypotassium maleate/acrylate 17 20000 78.2 140.7 Comp. 7 C18H37 18 10 -- 78.4 132.7 Ex.

9 C12H25 9 0 polysodium acrylate - 15000 77.3 158.3 *1 EO; ethylene oxide unit PO; propylene oxide unit *2 Number of residual ink drops per visual field. The minimum measuring unit is 100 m.

Example 2 Waste coloured woodfree paper was cut into pieces of 2 x 5 cm and placed in a deskl disintegrator.

Water, 1% (based on the raw material) of sodium hydroxide, 1.0% (based on the raw material) of sodium silicate, 2.0% (based on the raw material) of 30% hydrogen peroxide, 0.3% (based on the raw material) of a deinking agent and 0.2% (based on the raw material) of a disintegration accelerator were added to the disintegrator. The mixture was subjected to disintegration treatment at 55"C with a pulp concentration of 5% for 15 minutes, dehydrated with an 80-mesh wire to a pulp concentration of 18% and aged at 60"C for 90 minutes. The mixture was diluted with water to a pulp concentration of 4% and subjected to disintegraion treatment in the desk disintegrator for 5 minutes.The resulting mixture was subjected twice to a washing step which comprised dilution with water to a pulp concentration of 1% and dehydration with an 80-mesh wire to a pulp concentration of 10%. The resulting pulp slurry having a pulp concentration of 1% was treated with a TAPPI standard sheet machine to obtain a pulp sheet. The results are shown in Table 2.

TABLE 2

ru No. o 0 Deinking agent accelerator for Brightness o X o *2 9 7 reclamation of waste woodfree paper CS of Molar ratio Mw I R n m (Co)polyrner (comonomer < 0 of comonomers in drops r--M1/M2 9 Ci2H2s 9 X polypotassium acrylate co ED 128.2 10 C12H25 Z 11 polysodium acrylate 6000 77.0 93.0 oooo oooooo 11 Ci4H2a O O O O O O O O O Ex. O CiaHs7 t 5 polysodium maleate/methacrylate 1D 8000 75.9 O O O .o 13 C17H35C- 18 9 polyammonium maleate/acrylate 2.5 7500 76.7 100.7 14 o LO g N w E o ur t N Q j r > 0 polysodium maleate/methacrylate 11 25000 73.6 332.0 Comp. 17 C18H37 18 5 polysodium acrylate 21000 74.0 290.3 Ex.

18 C2H2 9 ~ polysodium maleate/acrylate 1.2 16000 74.2 279.0 2 2 E > ~ - X o 2 É E E E - E 's E E E t X U n r r E < < tn r r n m.2 S o o o o E X o o o o a o > > > > > > > > S.$ t m a m m a m O 80 A o ~ o ur o C C S O N C X S 1 = O 1 > Q ,C 1L1 I I I I I I N m n N v Q N Q N O ~ > 1 X t ID CD 1 > a) Q 2 x OE x *EO; ethylene oxide unit PO; propylene oxide unit *2 Number of residual ink drops per visual field. The minimum measuring unit is 100 m.

Example 3 Waste colored woodfree paper was cut into pieces of 2 x 5 cm and placed in a desk disintegrator.

Water, 1.0% (based on the raw material) of sodium hydroxide, 2.5% (based on the raw material) of sodium silicate, 5.0% (based on the raw material) of 30% hydrogen peroxide and 0.3% (based on the raw material) of a deinking agent were added to the disintegrator, followed by the addition of 0.3% (based on the raw material) of a disintegration accelerator. The disintegration was carried out at 50"C for 20 minutes with a pulp concentration of 5%. The mixture was aged at 500C for 60 minutes and diluted with water to a pulp concentration of 1.0%. The diluted mixture was subjected to flotation at 30"C for 10 minutes. The resultion pulp slurry was concentrated to a concentration of 6% and diluted with water to a concentration of 1%. The slurry was treated with a TAPPI standard sheet machine to obtain a pulp sheet.

Results are shown in Table 3.

TABLE 3 Disintegration accelerator for reclamation of waste woodfree paper

cu * 90 0 Or0036 CO n Fp y s ,% ~ X ao a) n LO cs ratio ink 00000 drops O O O O O O ≈ LO O X N N N Ex. 15 n Ls N acrylic acid H EO 15 CH3 (I)LO(V(V) Ln C12H2s 12 3 H EO 4 H K 45 5000 82.8 19.5 U > 30 10 H PO t H Na 19 2800 82.9 19.8 w C18H37 Z v methacrylic Z Z Z Z OIIIU I 19 QH4Ph- 7 t t O 0 cr, o o t C17H35C- t 5 maleic acid CH3 PO 2 H Na 2 5200 82.2 22.5 C (S) (: I I I I I C) c ,, s v S v aD E n o o o Lo Cl) 2E C n '$ O a N r L O = Q C LU ~ LO tV 1 > 00 0) 0 2 x Disntegration accelerator for reclamation of waste woodfree paper

ru nE E (R, Q C(R1)COO(AO)nR2 salt mer Mw Brightness of O R n m R1 AO n R2 molar Q) dual ratio ink " drops v, 21 (V03 O LO CD LO a) %-4 00 Comp. 19 C12H26 12 3 acrylic acid co to cç 0000 000 L oooo 888 Ex. t C13H37 30 10 CH3 PO n H Na O 5000 76.3 163.2 LoLncu " x - - - H EO 12 CH3 K 60 2500 78.5 113.5 Q O b e4 LO LO LO 22 C17H35C- 18 5 maleic acid H C0 H Na 1.5 3000 79.9 79.8 ?LZZL mI 23 CsH1sPh 9 0 CH3 - 0 H NH4 2.5 35000 76.2 164.9 S O t N methacrylic CH3 O O CH3 K 0.5 40000 76.8 148.0 ~ r O a-2o o CJ S I , tL LU ~ N e C U X O C > O s r e E E (z c n vo QC IE L \4 > 2 X r X vC o =O o =O L C LU N I X Q Q O I IN S) O v4 X t v4 N O 4 O 4 s4 O 4 Q *1 EO ethylene oxide unit PO; propylene oxide unit *2 Number ofresidual ink drops per visual field. The minimum measuring unit is 100 m.

Example 4 Waste colored woodfree paper was cut into pieces of 2 x 5 cm and placed in a desk disintegrator.

Water, 1% (based on the raw material) of sodium hydroxide, 1.0% (based on the raw material) of sodium silicate, 2.0% (based on the raw material) of 30% hydrogen peroxide, 0.3% (based on the raw material) of a deinking agent and 0.2% (based on the raw material) of a disintegration accelerator were added to the disintegrator. The mixture was subjected to disintegration treatment at 55"C with a pulp concentration of 5% for 15 minutes, dehydrated with an 80-mesh wire to a pulp concentration of 18% and aged at 60"C for 90 minutes. The mixture was diluted with water to a pulp concentration of 4% and subjected to disintegration treatment in the desk disintegrator for 5 minutes.The resulting mixture was subjected twice to a washing step which comprised dilution with water to a pulp concentration of 1% and dehydration with an 80 mesh wire to a pulp concentration of 10%. The resultign pulp slurry having a pulp concentratin of 1% was treated with a TAPPI standard sheet machine to obtain a pulp sheet. Results are shown in Table 4.

Disintegration accelerator for reclamation of waste woodfree paper

No. Deinking agent Monomer(M1) monomer (M comono- Number *2 ru R n m R1 AO n R2 molar (%) dual ratio ink r=M1/M2 drops z k (% 9 O v4 t N LO tD 1 > s CD O e t LO Ex. 22 - - o > N \4 U) LO s-4 X O LO v4 Ch s E t 3 i b 15 H LO " 6200 83.0 22.4 ooooooo 9 O O O O O O O O O O O O O O O O O O ON 26 tY) 18 5 maleic acid H v LO CH3 No 2 2700 81.8 53.0 27 C8H37 9 0 CH3 PO 12 CHa Na 19 7200 82.8 27.1 28 CsH1sPh 18 0'2 4 t > -4 LO m Z C12H2 Z 10 acrylic acid H EOPO 25 CH3 K 55 5000 78.3 103.5 Ex. 26 C12H2 Q 24 H PO Q H 0 o IIIII I 0000UIO 27 C18Ha7 O t maleic acid H EO 10 CH3 Na O 38000 77.8 124.3 d c (V r (V I I S b0 0 c, n a o o o o o o o 28 C17Ha5C (, s LU L L LU , (L , LU L LU t C9H1sPh r 5 .(f r r - - - 75.3 165.1 C .O v et sx F F < ) F c X o LO o o o t t t LO xC I N C0 CO O O O s4 C) > E LO s 4 c ,C LU (D O N N Q Q I N N Q N N X t LO CD 1 > CO LO (w 1 > CO O) N tsl 04 v 4 (S CN O4 v 4 04 04 v 4 04 Q 2 LLi F LXu *1 EO; ethylene oxide unit PO; propylene oxide unit *2 Number of residual ink drops per visual field. The minimum measuring unit is 100 m.

Claims (6)

1. A method for reclamation of waste paper, in which the disintegration and deinking step is effected with a deinking agent and an accelerator comprising a salt of a polymer selected from (1) (meth)acrylic acid polymer, (2) maleic acid polymer, (3) a copolymer of (meth)acrylic acid and maleic acid, (4) a copolymer of (meth)acrylic acid (M,) and (meth)acrylic ester (M2), (5) a copolymer of maleic acid (M,) and (meth)acrylic ester (M2), and (6) a copolymer of (meth)acrylic acid (M,), maleic acid (M2) and (meth)acrylic ester (M2), the polymers (1), (2) and (3) each having an average molecular weight of 10,000 or less, the polymers (4), (5) and (6) each having a monomer ratio (M1/M2) of 1 to 49.

2. A method as claimed in Claim 1, in which the polymers (1), (2) and (3) have an average molecular weight of 200 to 10,000 and the polymers (4), (5) and (6) have an average molecular weight of 1,000 to 10,000.

3. A method as claimed in Claim 1, in which said accelerator is a salt of the polymer with an alkali metal, ammonium or an alkanolamine.

4. A method as claimed in Claim 1, in which said polymer is (1), (2) or (3).

5. A method as claimed in Claim 1, in which said polymer is (4), (5) or (6).

6. A method as claimed in Claim 1, in which said (meth)acrylic ester has the formula (I).

wherein R, stands for a hydrogen atom or a methyl group; R2 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; AO stands for an oxyalkylene group having 2 or 3 carbon atoms and n stands for a positive number of 1 to 50.