FI108060B - Production of filled paper - Google Patents

Description

108060

MANUFACTURE OF FILLED PAPER

The invention relates to improving the stability of filled paper (including paperboard), in particular of the filler, in the manufacture of filled paper.

Filled paper is made by a process of forming a dilute suspension of cellulose fibers and filler (called a thin paper pulp), dewatering a thin paper pulp suspension to form a sheet, and drying the sheet. It is desirable to retain as much filler and fiber as possible in the sheet, including fine fibers, and often additive is added to increase the consistency of the thin paper pulp.

Thin pulp is generally made by diluting a concentrated suspension of filler and cellulosic fiber with water (especially circulating water obtained by dewatering). This more concentrated suspension is generally referred to as thick paper pulp.

A thick paper pulp can be made by mixing the required amount of fiber from a single source, filler from one source and water, or by mixing fiber and / or filler from a variety of sources and water.

Part of the supply of thick paper pulp may be recycled material, such as deinking stock, and if the recycled stock contains filler, the previously used filler will be included in the thick paper stock. Often, new filler is added to the thick or thin paper pulp.

Polymers having a broad molecular weight range can be used as a stick, and it is also known that a high molecular weight polymeric paste can be added to a thin paper pulp after adding a lower molecular weight coagulant to the pulp.

2 108060 It is presently known to treat a new filler with a polymeric coagulant before the filler is added to the thick paper pulp. The purpose of adding the coagulant is to coagulate the excipient and thereby improve its retention. Unfortunately, this process results in the filler giving less satisfactory results (i.e., it gives less opacity) and thus the addition of coagulant in this way is not entirely satisfactory.

In many methods for making filled paper, cationic active high molecular weight adherence is added to thin paper pulp made from good quality paper pulp (low cation requirement). In such methods, the addition of a retention agent generally results in an increased retention of both filler and fine fibers, EP-A-17353 discloses a relatively crude paper stock having a high cationic need, with bentonite followed by a substantially nonionic polymeric retention aid. AU-A-63977/86 describes a modification wherein, although this process employs a substantially fillerless suspension, a filler may be added to the suspension and the benonite is added to a thick paper pulp which is then diluted to form a lightweight pulp. * a cationic active polyelectrolyte followed by a nonionic high molecular weight adherent. Thus, this process uses a coagulating polymer and is added to the thin paper pulp after the bentonite.

Methods similar to those described in EP-17353 and AU-63977/86 are satisfactory for making paper from a suspension having a relatively high cationic requirement and a relatively low filler content, but these methods give relatively poor results in filler retention when the suspension contains significant amounts of filler.

3 108060

It would be desirable to obtain improved filler retention in papermaking processes such as those described in EP-17353 and AU-63977/86.

The process for producing the filled paper according to the invention comprises the following steps: - preparing an aqueous feed suspension containing from 2.5 to 20% by weight of filler and cellulose fiber in a ratio of 10: 1 to 1:50 based on dry matter, - preparing an aqueous thin paper pulp slurry consisting of a feed suspension or made from a feed suspension in which at least 30% by weight of the pulp used for the production of the thin paper pulp is selected from the group consisting of deinking pulp, mechanical pulp, heat pulp and chemimechanical pulp, forming a thin pulp, - subsequently adding a polymeric retention to the thin pulp, - dewatering the thin pulp to form a sheet, and drying the sheet, and in this process - coagulating the filler with the fiber n in the feed suspension by adding a cationic active coagulant to the feed suspension.

Although it is known to add similar cationic active coagulants to the filler prior to its addition to the feed suspension or the thin paper pulp, a significant improvement is achieved by adding the coagulant at a time when the filler is in admixture with the fiber in a relatively concentrated filler and fiber suspension. There seem to be three reasons for this. First, the presence of the fiber with the excipient means that the excipient coagulates in the presence of the fiber, thereby "forming aggregates of the excipient and fiber, which then remain in the sheet during dewatering, thereby improving stability. Secondly, as the coagulant is added at a relatively concentrated may more effectively affect the material in the suspension to form aggregate aggregate and fiber aggregates and the efficacy of the coagulant cannot be reduced, for example, by chemical interactions of wastewater or other dilution water impurities used to make thin paper pulp 4 108060. Third, if the fine fiber concentration is low.

The thick paper pulp may consist of a fully defined aqueous feed suspension, in which case this feed suspension is diluted after the coagulation step to form a thin paper pulp. Generally, however, a thick pulp is prepared by mixing a defined aqueous feed suspension with one or more concentrated cellulosic fiber-containing suspensions.

Generally, as much of the filler as possible is treated with a coagulant in the presence of the fiber as described. However, it may be desirable to add a small amount of filler separately, i.e., thin paper pulp to provide faster fluctuations in filler additive to maintain a predetermined quality. A small amount of filler may enter the thin paper pulp when diluting the thick pulp with the recycled water from the dewatering step. For example, generally at least 50%, and preferably at least 70%, of the total amount of filler in thin paper pulp is treated as above. Preferably, at least 50%, and generally at least 70%, of the thick pulp filler is treated as above and in some methods it is possible to treat 100% of the thick pulp filler in this manner.

The filler for the thick pulp generally comes from partially recycled cellulosic material and some is newly added (i.e., new) filler. The recycled cellulosic material may be recycled paper or coated paper, or, in particular, deinking pulp obtained from filled paper.

According to the invention, the filler is added to the feed suspension containing the filler and cellulose fiber by adding 108060 5 cellulosic material (in particular deinking stock) or both containing a new filler or recycled filler.

Preferably, the feed suspension used contains substantially all of the filler material derived from the recycled cellulosic material to be added to the thick paper pulp, so that substantially all recycled cellulosic material (i.e., at least 70% and preferably 100%) (including filler) is present in the feed suspension. The feed suspension preferably contains a portion (i.e. at least 25% or generally at least 50% by weight) or substantially all (i.e. at least 70% and preferably 100%) of the new filler material desired for the final thin paper stock.

In a preferred method, a thick paper pulp is prepared by mixing at least one substantially filler-free cellulose fiber suspension with an aqueous feed suspension prepared by mixing a new filler with a de-icing barrier (and optionally another stock) and coagulating the fibers with this feed suspension. The coagulated feed suspension is mixed with the other fibrous suspension or suspensions to form a thick paper pulp which is then diluted to a thin paper pulp.

The feed suspension to be coagulated must have a total solids content of at least about 2.5% by weight and generally at least about 3% by weight. At a solids content of more than 10%, the viscosity and flow characteristics of the suspension may result in poor handling and the solids content of the suspension will generally not exceed about 6%. Generally, the solids in the suspension consist wholly or substantially of a filler and cellulosic fiber (including fine fibers).

It is necessary for the feed suspension to contain fibers (including fine fibers) during coagulation. Preferably, the amount of fine fibers is minimized. The amount of cellulosic fibers in the feed suspension (including fine fibers) should generally be at least about 0.1 parts by weight dry weight per filler, because if this amount is lower the amount of fibers is not sufficient to achieve the desired benefit. Generally, the amount of fiber is at least about 0.5 to 1 part and always 10 parts per filler part. When the amount of fibers rises to more than 50 parts per part by weight of filler, the economic value of the invention may be quite small, since in that case the total amount of filler in the final paper would inevitably be low, so that filler retention does not become a problem.

The amount of filler in the thin paper pulp is typically in the range of about 0.05 to 3 parts by dry weight, preferably 0.1 to 1 parts by weight, of dry weight cellulose fiber. The filler content of the finished paper is generally about 2 to 50%, often more than 5% or 10%, and often always 20% or 30%, based on the total dry weight.

The filler may be any of the fillers used to make the filled paper, including kaolin and calcium carbonate.

The total dry solids content of the thick pulp is generally in the range of about 2.5 to 10%, generally in the range of about 3 to 6% by weight, and the total dry solids content of the thin pulp is typically in the range of about 0.25 to 2%.

* · The cationic active coagulant added to the aqueous feed suspension may be an inorganic coagulant such as aluminum sulfate, sodium aluminate or polyaluminium chloride or sulfate, but is preferably a cationic polymeric coagulant. This may be a cationic naturally occurring polymer (including modified natural polymers) such as cationic starch, but is generally a synthetic low molecular weight cationic polymer generally having an intrinsic viscosity of less than about 3 dl / g. The intrinsic viscosity is determined by a suspended level viscometer at 25 ° C in a 1 molar aqueous solution of sodium chloride buffered to pH 7. Generally, the intrinsic viscosity is between · * 0.1 to 3 dl / g and the best results are generally obtained between 7 108060 and 0 , 2 - 2.4 dl / g. Suitable polymers generally have a molecular weight, as measured by gel permeation chromatography, of less than 2 million, preferably less than 1.5 million, and most preferably less than 1 million, and often less than 100,000, m.p. up to 30,000 albeit lower values, i.e. up to 10,000 are suitable for some polymers such as dicyandiamides.

The coagulant polymer may be polyethyleneimine, dicyandiamide or polyamine (i.e. obtained by condensation of epichlorohydrin with an amine), but is preferably a polymer of an ethylenically unsaturated cationic monomer which is optionally copolymerized with one or more ethylenically monomeric monomers. Suitable cationic monomers include dialkyldiallyl quaternary monomers (in particular diallyl dimethylammonium chloride) and dialkylaminoalkyl (meth) acrylamides and (meth) acrylates in the form of their acid addition or quaternary ammonium salts. Preferred polymers are diallyl dimethylammonium chloride polymers or quaternized dimethylaminoethyl acrylate or methacrylate polymers, either as homopolymers or copolymers with acrylamide. The copolymer generally comprises 50-100%, often 80-100%, of the cationic monomer, the remainder being acrylamide or other water-soluble nonionic ethylenically unsaturated monomer.

The amount of coagulant polymer added to the feed suspension is typically in the range of about 0.005% to 2%, preferably about 0.01% to 1%, based on the dry weight of the suspension, but when the coagulant is inorganic it may typically be in the range of about 2% to 10%. about 5%. The amount of organic coagulant, based on the dry weight of the paper, is typically about 0.005-0.5%, preferably 0.01-0.2%.

Generally, it is desirable that the coagulant be added to the pulp containing the filler and fiber at a defined step (namely, a feed suspension containing the filler and fiber). However, the coagulant may also be added in other 8 108060 steps. For example, when it is desired to add conventional additives such as additives for resin protection, for example, to the original fibrous thick paper stock, conventional low molecular weight cationic polymers may be used.

The invention can be applied to a large variety of paper pulps, including paper pulps that are relatively pure and have a low or relatively low cation requirement. However, one advantage of the process is that it can also be used successfully when the thin paper pulp contains relatively large amounts of anionic waste material. The waste material may be formed when the thin paper pulp is formed in significant amounts (i.e., at least 30% by weight and often at least 50% by weight based on the total weight of the pulp) deinking pulp, mechanical pulp, hot pulp or chemimechanical pulp. It can be the result of long-term recycling of recycled water, even when using the above-mentioned pulps at low weight ratios (based on total pulp).

Generally, the anion content of such a thin paper pulp is such that the need for a thin paper pulp cation is relatively high (when no coagulant is added). For example, this can reach a value of at least 0.6%, and generally at least 0.1% when the thin paper pulp is in accordance with the present method but in the absence of coagulant and when titrating a sample of the thin pulp with polyethyleneimine (PEI) how much polyethylene imine must be added before a significant improvement in staying is achieved. A value of 0.06% indicates that a PEI increase of at least 600 g / t is required to achieve a significant improvement in persistence.

Another way to express the need for a cation is to filter a sample of fine paper pulp through a rapid filter paper and titrate the filtrate with a standardized polyDADMAC solution, using, for example, the Mutec Particle Charge Detector. A thin paper pulp having a high cationic need to provide a filtrate having a concentration of 108060 9 anionic charges generally greater than 0.01 millimole / L, and often greater than 0.1 millimole / L.

The anionic active fines are added to the pulp before the polymeric adherent is added. The fines may be added to the thin paper pulp or to the thick paper pulp, but when added to the thick pulp, it must be added after the coagulant, otherwise it may coagulate with the fiber and filler. When there is only one feed of thick paper pulp, it must be added to this feed after coagulation, but when there are multiple feeds, it can be added either after the feeds have been mixed with each other or in a feed to which no coagulant has been added.

The finely divided material can be any swelling clay and is generally a material called bentonite. Usually, green swelling clay, montmorillonite or hectorite, such as described in EP-17353 or EP-253893, is used as the swelling clay. The materials available under the commercial names "bentonite and" Fullers Earth "are suitable. Instead of the swelling clay, other anionic substances having a very large surface area may be used. They should have a very small particle size, e.g. less than 3 µm and preferably less than 0.3 µm. and even less than 0.1 µm. Examples of these are silica-containing substances such as finely divided polysilicic acid derivatives, zeolite, and anionic polymeric emulsions. Amphoteric clay or polymer (containing some cationic active groups and generally higher amounts of anionic clay or polymer may also be used) ) groups.

The amount of bentonite or other fines added is generally from about 0.02% to about 2% by weight on a dry weight basis relative to the dry weight of the suspension.

The polymeric binder used in the invention is preferably a synthetic polymer having an intrinsic viscosity of greater than about 4 dl / g and often greater than about 6 dl / g.

108060 ίο

The resin may be cationic, in which case it is generally a copolymer of acrylamide and up to 50% by weight of a cationic raonomer, usually a dialkylaminoalkyl (meth) acrylate or acrylamide salt. It may be anionic, in which case it may be a copolymer containing up to 50% by weight of the anionic ethylenically unsaturated monomer, usually sodium acrylate.

Preferably, however, the polymer is substantially nonionic. It may also be selected to be completely nonionic, for example, it may be a polyethylene oxide or polyacrylamide dihomopolymer (optionally containing up to 2 mole% sodium acrylate in the polymer), or it may be slightly anion active or slightly cationic. For example, it may contain up to 10-15 mole% of anionic groups and up to 5-10 mole% of cationic groups.

Preferred polymers are those having an intrinsic viscosity of at least 4 dl / g and comprising acrylamide alone or containing up to 5 mol% of cationic groups (preferably a quaternary salt of dialkylaminoalkyl acrylate or methacrylate) and / or up to 8 mol% of anionic groups (preferably ). Other water-soluble acrylate salts or other anionic monomers may also be used instead of sodium acrylate.

The amount of polymeric retention agent added is generally between 100 and 1500 g per ton of dry matter. The optimum amount may be determined according to conventional methods.

The papermaking process as a whole, except for the mentioned addition of coagulant and filler, can be conventional and can produce newsprint or other types of paper, including cardboard.

The following are some examples. Each of these mildly anionic adherents is a copolymer consisting of 11 108060 95 mole% acrylamide and 5 mole% sodium acrylate and has an intrinsic viscosity of 12 dl / g.

Example 1

An aqueous feed suspension was prepared by mixing 10% (based on total solids) of burnt clay filler (DIP) to form an aqueous feed suspension of 3.5% total solids to 1: 4 solids to fiber. In the second experiment, the aqueous feed suspension was formed exclusively from DIP.

The feed suspension was mixed with a suspension consisting of TMP,

Gounwood and Magnafite pulp (hereinafter referred to as pulp feed). The mixture of these suspensions gave a thick paper pulp with a total filler content of 16% and a total fiber content of 84% based on the total dry matter.

This thick paper pulp was then diluted with clarified circulation water to give a thin paper pulp having a solids content of 0.79%.

4000 g / t bentonite was added to the thin paper stock suspension, and after thorough mixing, 400 g / t (based on dry matter) of a slightly anionic polyacrylamide suspension was added and mixed. The treated light pulp was dewatered to form a sheet and dried.

In the process of the invention, a cationic coagulant consisting of polydiallyl ammonium chloride having an intrinsic viscosity of about 0.4 dl / g was added in the amounts and process steps given below. A first pass stay was ordered.

Addition point A is an addition to an aqueous feed containing only DIP. B is an addition to an aqueous feed containing DIP and burnt clay. C is an addition to the "pulp feed". D r is the addition of fine pulp before the addition of bentonite. '12 108060

Table 1 Cationic Active Cation Active First Pass Coagulant Coagulant Persistence (%) Dose (g / t) Incremental Step _ _0 __-___ 80.6_ 500 A 81.5 _1000__A ___ 82.6_ 500 B 82.6 1000 B 83.4 _2000__B__85.8_ 500 C 80.6_1000 1000 D 78.4 _2000__D 7 9.6 These results clearly show that the addition of a cationic coagulant to a thin paper pulp reduces the stability, and that adding the coagulant to the unfilled paper pulp does not result in a significant improvement, whereas the improvement to remain by the addition of cationic with premixed burnt clay.

Example 2

An aqueous feed suspension was prepared by mixing mooncurrant (TMP) cold alkali pulp (CCS) and unbleached sulphate cellulose (UBK) to give an aqueous feed suspension which was then mixed with the burnt clay filler. The mixture of these suspensions formed a thick paper pulp having a dry solids content of 3.5% and a filler to fiber ratio of 1: 1.5 on a dry weight basis.

108060 This thick paper pulp was diluted with circulating water to give a thin paper pulp having a filler content of 26%, a fiber content of 74%, and a dry matter content of 0.887%.

Bentonite was added to this suspension at 3000 g / h, unless otherwise stated, and after thorough mixing, 250 g / h of mildly anionic polyacrylamide was added and mixed. The treated thin pulp was then dewatered to form a sheet which was dried.

In the process of the invention, a cationic active coagulant consisting of polydiallyl dimethylammonium chloride (polyDAMAC) with an intrinsic viscosity of 0.4 dl / g was added to the clay alone or to various clay fiber suspensions shown in Table 2, and first pass constants were determined.

Table 2 Cationic Act. coagulant. . , cationic act. addition step f? okku? 'first pass coagulant in the rock. substance dose (g / t) dose (g / t) persistence 0 - 100 45.0 0 - 250 53.8 _0 __-__ 500 ___ 66.3, * 3000 burnt clay 2 50 52.0 6000 "250 52 ^ 8 _9000__2__ £ 12__55.2 3000 thick paper pulp + burnt clay 250 55.2 6000 "250 60.2 9000 __" __ 250__69.2 thin paper pulp 3000 (pre-bentonite) 250 51.2 6000 "250 52.6 9000 __ [__ 250__52.1 thin paper pulp 3000 (post-bentonite) 250 46.3 6000" 250 41.4 9000 "__ 250 ___ 40.0 3000 circulating water + burnt clay 250 50.2 6000 "250 48.9 9000" 250 50.7 ............ 1 - ~! 1 Ί 08 060 14

The above results clearly show that the addition of the cationic active coagulant after the addition of the bentonite (as in AU application 63977/86) reduces the stability. Adding it to burnt clay gives minimal or poor results, while adding it to a thick paper pulp containing pre-mixed burnt clay improves first pass retention.

Example 3

For a paper pulp similar to Example 2, two systems were tested. One of these was similar to the paper pulp used in Example 2, in which a poly-DADMAC coagulant was added to a thick paper pulp containing burnt clay. In another system, denoted by * in Table 3, bentonite was added to the blended thick paper pulp, and this was diluted to a thin paper pulp, modified polyethyleneimine coagulant was added to the thin paper pulp, and then a retention agent was added. In this process, the burnt clay was added to the thick paper pulp before the coagulant.

Table 3 I - - Γ- = —----------- ---- I - Cation Act. ,. . . . . ... anion act. first pass L ht * 'pro · »dose (g / t) additive dose (g / t) {%) r (%) I -------—----—---- IO - O 40.4 3.0! 0 "100 47.6 15.4 '0" 250 53.5 28.2 _0 ____ "_ 500__71.0__49.0 Thick Pulp + 1500 Burnt Clay 250 54.3 34.7 3000 ·' 250 59.4 42.4 6000" 250 61.6 46.9 9000 ___ "__ 250 __62.2__51.2 0 * "250 59.5 36.6, 1500 * (Post Bentonite) 250 52.9 27.1 ί 3000 *" '250 42.3 10.3 i | 6000 * __ 250 39.4 0.6 These results clearly show that by adding cationic coagulant to thin paper pulp after bentonite (as in the AU application) 63977/86) reduces stability, while the best stability improvement is achieved when the cationic active coagulant is added to a thick paper pulp feed suspension containing burnt clay.

Comparing the first pass residues in Table 3 and the first pass residues in the ash, it can be seen that the addition of the cationic active coagulant to the thick paper pulp containing the burnt clay specifically promoted the incineration of the ash first because the first ash residues were higher. after the addition of the bentonite, the cationic active coagulant was added to the thin paper pulp.

Example 4

The paper mill has operated using the pulps of Examples 2 and 3, where bentonite was added to the thick paper pulp and the entire burnt clay was added to the thin paper pulp.

Based on the recommendations from the laboratory tests of Examples 2 and 3, the paper mill modified its wet head chemistry and performed a test run using the addition of cationic active coagulant.

Of the burnt clay generally added to the thin pulp, 75% was now added to the thick pulp such that the thick pulp and the thin pulp contained a ratio of 3: 1. The mixture of thick paper pulp and burnt clay was then always treated with 400 g / t polyDAMAC coagulant (dry coagulant based on total dry matter content of the pulp).

After mixing the treated thick pulp, it was diluted with circulating water and the remainder of the clay was added to give a thin pulp. Bentonite and anionic polyacrylamide were added immediately before and after the last intersection, respectively, before the headbox.

By dividing the feed of the burnt clay, most of the clay was treated according to the invention, while the addition of clay to the thin paper pulp allowed the paper mill to adapt quickly to sheet capacity. [16108060

When using 400 g / t (as dry polymer per dry paper) of the cationic coagulant of Examples 2 and 3, the paper mill received the following advantages over the non-coagulant method: a) 29% reduction in total burnt clay flow b) 51% reduction in headbox ash c) 53% reduction in circulating water ash d) Increase in opacity of paper from 89 to 91.

Since opacity was the only criterion for assessing the addition of burnt clay, the paper mill could still have reduced the use of burnt clay while still achieving the product quality requirement for opacity.

Example 5

An aqueous feed suspension was prepared by mixing TMP and DIP with a thick paper pulp ratio of 1.5: 1 on a dry weight basis to obtain an aqueous feed having a total solids content of 3.3% and having a ratio of filler to fibers (including fine cellulose fibers) of 0, 05: 1 based on dry matter. Thick cellulose pulp was diluted with clarified recycled water to a solids content of 0.9%.

The benonite (B) used in the various order and process steps shown in Table 4, Examples 2, 3 and 4, was added at 4 kg / h and the polyDÄMAC coagulant (C) was added at 0.5 kg / h. In all experiments, 0.4 kg / t of mildly monoactive polyacrylamide was added as a final step in the final step.

Thin paper pulp filtrates were subjected to a standard first pass determination of turbidity, turbidity and cation demand, the results of which gave an indication of the effectiveness of using various addition steps in the papermaking process to maintain and remove soluble and colloidal materials from the aqueous phase.

Table 4 first second filtrate filtrate first pass addition increase cation need consistency constant ___ milliequiv / 1 __ (NTU) __ C thick B thick 0.149 13.3 82.1 B thick C thick 0.115 14.5 79.8 C thick B Thin 0.108 12.0 83.1 B Thick C Thin 0.156 14.0 80.8 C Thin B Thin 0.116 12.0 81.9 B Thin C Thin 0.110_13.0_80.5_

As shown in the table, the best results for first pass retention were obtained each time the cationic active coagulant was added first, with the optimum addition steps being that the cationic active coagulant was added to the thick paper stock and the bentonite was added to the thin paper stock. In addition, the optimum addition steps for first pass stability were also the optimum addition steps for soluble and colloidal materials from the aqueous phase as measured by consistency and cation requirement.

By adding bentonite to the thick paper pulp and the cationic active coagulant to the thin paper pulp (as in AU application 63977/83), relatively low first pass retention and relatively high consistency and cation demand are achieved.

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Claims (11)

A process for preparing filled paper, wherein an aqueous feed suspension containing 2.5 - 20% by weight of filler and cellulose fiber in the ratio of 10: 1 - 1:50 calculated according to dry matter is removed, - an aqueous thin paper pulp suspension is removed water dilute an aqueous thick pulp, which is constituted by the feed suspension or made from the feed suspension, in which eating sample 30% by weight of the cellulose used for the preparation of thin pulp is selected from a group comprising deinked cellulose pulp , mechanical pulp, thermomechanical pulp and chemical mechanical pulp, - is added anionically active finely divided material in the thin pulp or thick pulp from which the thin pulp is formed, - then a polymeric retention agent is added to the thin pulp, - the thin pulp for forming a sheet and wiping the sheet, characteristic in that the filler is coagulated with the fiber of the feed suspension by adding in the feed suspension a cationic coagulant. 2. A process according to claim 1, characterized in that recycled cellulose material is added to the thick pulp, and substantially all recycled cellulose material is in said feed suspension. 3. A process according to claim 2, characterized in that the filler in the thin pulp also comprises new filler and that in said suspension 50% by weight of said new filler is added. 4. A process according to claim 1, characterized in that said feed suspension is manufactured by incorporating new filler into the deinked cellulose pulp, and since the filler has coagulated with the fiber of the feed suspension on the effect of the added 108060 cell pellet, the feed pellet is mixed with filler. Process according to any of the preceding claims, characterized in that the amount of cellulose fiber in said feed suspension is 0.5 - 10 parts by weight per one part by weight of filler. Process according to any of the preceding claims, characterized in that the coagulant is an inorganic coagulant, a cationic natural polymer or a synthetic cation-active polymer, whose intrinsic viscosity is below 3 dl / g. Process according to claim 6, characterized in that the coagulant is a synthetic polymer selected from the group; polyethylenimine, dicyandiamide polymers, polyamines and polymers constituting 50 to 100% of the following cation-active monomers, which include dialkyldiallyl quaternary monomers, dialkylaminoalkyl (meth) acrylates and dialkylaminoalkyl (meth) acrylamides and 0-50% by weight acrylamide. Process according to any of the preceding claims, characterized in that the cation requirement of the thin paper variety is above 0.1 mmol / l. 9. A process according to any of the preceding claims, characterized in that the polymeric retention agent is a synthetic polymer selected from the group; polyethylene oxide, polyacrylamide homopolymer, and copolymers of acrylamide having up to 5 mole percent cation-active monomer and / or up to 8 mole percent anion-active monomer. Process according to any of the preceding claims, characterized in that the anionic atomized material is bentonite. Method according to any of the preceding claims, characterized in that the anionic active atomized material is. bentonite and that it is added to the thin pulp.