DE2262906A1 - Dewatering of paper - accelerated by polyamide amines polyether amines and polyethylene imines, with addn of bentonite - Google Patents

Abstract

Dry bentonite 1-10wt.% and opt. Al2(SO4)3 0.5-3wt.% based on wt. of dry paper, are added to aq. cellulose fibre suspensions contg. polyamide amines, polyether amines or polyethylene imines as dewatering accelerators. The bentonite is pref. obtd. by activating montmorillonite clays with univalent cations. The detrimental effect of impurities e.g. humic acid, waterglass, starch, CMC, and slime on the action of the dewatering accelerators is overcome. Prodn. of paper and cardboard is increased, loss through the sieve is reduced by >100%, and the bentonite is retained in the paper.

Description

Process for improving the dehydration-accelerating properties of polyamide amines, polyether amines and polyethylene imines in cellulose fiber suspensions.

The present invention relates to a method of improvement the dehydration-accelerating properties of polymidamines, polyetheramines and polyethyleneimines in paper, cardboard and cardboard production.

In the production of paper, cardboard, cardboard, etc. - briefly below "Paper" called - is known to be a cellulose fiber suspension, depending on the desired product more or less high proportions of resin glue and mineral Components (Fillers) may contain on a continuously moving sieve drained. The free water drips through the paper web while all remaining water is removed by suction and subsequent drying, e.g. on drying rollers. An important factor for paper production is the speed at which the water passes through the paper web or can be sucked off. The drainage rate of the cellulose fiber suspension depends to a large extent on the composition of the suspension and the degree of freeness of the fibers and on the mesh size of the sieve. With the addition of certain chemicals the drainage rate can be increased without causing diarrhea is increased. Fast drainage either means lower drying costs or an increase in production.

The addition of such drainage devices is particularly interesting when processing waste paper or highly ground cellulose (parchment substitute), because here the drainage through increased proportions of fine fibers and mucilage is strongly inhibited.

It is known that pulp suspensions can be reduced by adding dehydration of divalent metal ions, especially calcium chloride, faster and better let (J.C. Mac GuganJ Paper Trade Journal, Jan. 1962> 5. 22). According to W.C. Cohen et al., Proc. Austr. Pulp Paper Ind. Techn. Assoc.

Vol. 3 (1949), p. 72 on the neutralization of anionic groups the fabric fibers by positive metal ions. This leads to the formation of fiber agglomerates, which allow easier removal of the water from the pulp suspension.

Unfortunately, the hardness of the water plays an important role in this process Role. It has been shown that the drainage effect decreases with increasing hardness. But since the paper manufacturers mostly rely on surface or groundwater with medium or higher water hardness is dependent on the application of calcium chloride limited to a few cases where soft water is actually present.

Calcium chloride has a detrimental effect on the dehydrating effect also the use of resin glue and aluminum sulfate, making it economical Working with this is only guaranteed with unsized papers. Additionally, that when calcium chloride is used, there is a slightly increased tendency to corrosion Steel and brass compared to normal process water is observed.

From the German patent specification No. 1 169 131 it is also known that polymerization products based on ethyleneimine, e.g. polyethyleneimine, are suitable are to accelerate the dewatering of pulp suspensions. The Belgian Patent specification no. 721 332 and DOS 2 127 C82 describe that polyamide amines or polyether amines are also suitable as dehydrating agents used too will. In addition to other effects, all of these products also have a retention effect Effect and thereby reduce the solids load on the water cycle (H. Wilfinger, Das Papier, Vol. 2 [1948], p. 265). With a lower wastewater pollution is generally associated with better sewage treatment, what the papermaker Easier put in a position to comply with the legislative requirements to meet the discharge of waste water into the receiving waters.

The mentioned dehydrating agents based on polyethyleneimine, polyamidamine or polyether amine also have a number of disadvantages. So it has been shown the polyalkylenimines, polyamidamines or polyetheramines sensitive to humic acid, Water glass, starch, CMC and mucilage are, i.e. their effectiveness decreases increasing amounts of these interfering compounds in aqueous solution.

In numerous cases, however, the papermaker is on the point of using it of process water containing the above-mentioned interfering compounds.

It has now been found, surprisingly, that when you use the cellulose fiber suspension in addition to the dehydrating agent, also aluminum sulfate and bentonite, preferably was previously activated, admits, the dehydrating agent practically retains its full effectiveness, even in the presence of the above-mentioned interference compounds.

The present invention therefore relates to a method for improvement the dehydration-accelerating properties of cellulose fiber suspensions of polyamide amines, polyether amines and polyethylene imines in the presence of the dehydration-disruptive Substances, characterized in that one has a close, based on the dry Paper stock, from 1 to 10% by weight of dry bentonite and optionally from 0.5 to 3% by weight of aluminum sulfate is added to the cellulose fiber suspension.

The dehydration accelerators of the type polyamidamine, polyätherajiiin, Polyethyleneimine etc. are used as usual in quantities of 0.02 - 0.2 ffi active substance, based on dry paper stock, added shortly before the headbox. Particularly Polyamidamines which, according to Belgian patent no. 721 552 can be obtained.

A bentonite, which is produced by activating montmorillonite-like Clay minerals with monovalent cations such as Na, K, NH4 or H ions were obtained, used. The bentonite obtained in this way is hereinafter referred to for short as "active bentonite".

The most important advantages of the method according to the invention are that in paper stocks where the presence of interfering substances such as humic acid, Water glass, starch, CMC, mucilage no dehydration-accelerating effect could be achieved with cationic polyelectrolytes, now also good ones Drainage effects and thus an increase in production of 5-15 ß and a reduction of the sieve failure by more than 100%.

Because the bentonite used is almost completely in the paper by weight is withheld, the process is particularly economical.

The usual, Minerals containing silicate or sulfate used in the paper industry, such as Kaolin, china clay, talc and barite, as well as titanium dioxide added will.

The inventive method can be used both for Processing of fiber suspensions obtained from fresh pulp, as well as suspensions obtained by recycling waste paper became.

A preferred application is in the manufacture of cardboard, where -The drainability of the middle layer on the round sieves improved, as well as the Sieve diarrhea is reduced.

The following examples explain exemplary embodiments of the invention.

The percentages are percentages by weight and are based on the dry stock based.

The turbidity of the filtrate obtained in the drainage test was made in the transmitted light method with a spectrophotometer at 460 p and a cuvette diameter of 1 cm determined (the device was calibrated to distilled water = 100).

The drainage time was measured with a modified Schopper-Hiegler device determined. The value obtained is called OR.

The time that is used for the drainage effect is used as wet for the drainage effect A certain amount of filtrate emerges from a containing a dehydrating agent Suspension of a certain paper stock composition is required in comparison to those who take a corresponding amount of filtrate from an auxiliary-free suspension needed. The test method used is in leaflet V / 7/61 of the "Verein der Zellstoff-und Paper chomicians and engineers ”.

Example 1 A paper stock with a consistency of 2 ff and a 1 final size from 50 ° SR consists of 70% wood pulp (equalized), 30% sulphite pulp produced using humic acid-containing water.

Those given in Table 1 were given to a toilet of this paper stock Amounts of active bentonite B 1 (product from Erb @ Löh, Germany) added, which is as follows was prepared A 10% slurry was prepared in a turbo stirrer, the @ was then diluted to 5% with water.

A swelling time of 14 hours was then allowed before use adhered to.

After adding the active bentonite, 1% Al2 (SO4) 3 was added and the @ drainage time, determined by adding to 125 ml of the described: paper stock suspension the amounts of polyelectrolyte solution indicated in Table 1 were added.

Table 1 shows three dehydrating agents that are widely used in practice with and without the inventive addition of bentonite and Al2 (SO4) 3.

TABEL Polyelectrolyte Paper stock without Cartaretin F Cartaretin K Polymin SN 0.10% AS 0.25% AS 0.10% AS 0.15% AS 0.10% AS 0.15% AS Dev. Tr. Dev. Tr. Dev. Tr. Dev. Tr. Dev. Tr. Dev. Tr. Dev. Tr. sec. sec. sec. sec. sec. sec. sec. untreated 80 43 82.0 42.0 83.0 44.2 88.2 45.0 89.3 52.0 88.1 46.0 89.3 48.2 + 1% Al sulfate 98.2 79.5 96.3 78.2 99.2 80.0 99.8 81.9 103.4 82.0 98.2 80.0 99.5 81.2 + 1% Al sulfate + 5% Rentonit B1 96.6 79.6 69.2 84.9 45.4 89.5 77.6 83.6 55.2 87.8 76.0 82.0 63.2 87.0 + 1% Al-sulfate + 10% bentonite Bl 120.8 77.1 68.4 84.4 40.7 92.2 - - - - - - - - Legend: AS means active substance Dev. Bedoutet dewatering speed Tr. Means turbidity Cartaretin F is a polyolectrolyte based on polyetheramine Cartaretin K is a polyelectrolyte based on polyamide polyamine Polymin SN is a polyelectrolyte based on polyethyleneimine Example 2 From a waste paper material, which is predominantly consisted of waterglass-glued corrugated cardboard and was opened in a pulper, the achievable drainage properties were examined as described in Example 1, with and without the addition of active bentonite. SO4) 3 based on dry fiber material was added.

The values obtained are shown in Table 2. In the table 2 there are four dehydrating agents used in PraxIs vlel with and without the According to the invention, the addition of bentonite and Al2 (SO4) 3 was compared.

TABLE 2 Polyelectrolyte Paper stock. without Cartaretin F CartaretinK Polymin SN Retaminol E 0.12% AS 0.16% AS 0.12% AS 0.12% AS 0.12% AS Dev. Tr. Dev. Tr. Dev. Tr. Dev. Tr. Dev. Tr. Dev. Tr. sec. sec. sec. sec. sec. sec. untreated 35.6 7.4 43.2 20.5 - - 42.8 40.2 44.6 32.8 45.0 34.0 + 1% Al sulfate + 5% bentonite Bl (+) 55.9 12.5 59.9 35.7 - - 33.0 63.5 - - - - + 2% Al sulfate + 5% bentonite Bl (+) 62.7 17.0 42.2 53.2 - - 26.6 74.3 - - - - + 2% Al sulfate + 5% bentonite Bl (o) 39.0 11.9 44.1 30.3 36.5 45.7 21.0 63.7 20.2 62.1 39.1 47.8 Legend: (+) = prepared as described in example 1 (o) = dry sprinkled into pulper AS means active substance Enw. means dewatering speed Tr. means turbidity Cartaretin F is a polyelectrolyte based on polyether polyamine Cartaretin K is a polyelectrolyte based on polyamide polyamine Polymin SN is a polyelectrolyte based on polyethyleneimine Rctaminecl E is a polyelectrolyte based on a polyamine present as a hydrochloride.

Claims (3)

P a t e n t a n s p r ü c h e 1. Process for improving the dehydration-accelerating properties of polyamide amines, polyether amines and polyethylene imines in the paper and cardboard industry, in the presence of substances interfering with drainage, characterized in that that you have an amount, based on the dry paper stock, between 1 and 10 wt .-% dry bentonite and optionally 0.5 to 3 wt. aluminum sulfate of the cellulose fiber suspension admits. 2. The method according to claim 1, characterized in that one a bentonite, which by activating montmorillonite-like clay minerals with monovalent cations obtained. 3. Paper and cardboard produced according to the method according to claims 1 and 2.