NO144222B - PROCEDURE FOR AA PREVENTING RESPONSE PROVISION IN MANUFACTURE OF PAPER, CARTON AND PAPER - Google Patents

Description

The object of the present invention: is a method for preventing resin precipitation in the production of paper, cardboard and cardboard.

The occurrence of resin difficulties is in the paper industry a problem which must not be underestimated. The difficulties remain

in that resins, which are present in the cellulose and the grinding mass or which originate from unconsumed portions from the paper sizing, coagulate and settle in pipelines, on the walls of raasse processing facilities and vessels, on the sieves, felt, presses and r dryers. This leads to contamination and sticking to a reduction in drainage, to the formation of spots on the paper and to frequent paper breaks and therefore to faulty manufacturing.

is and production loss.

Attempts have already been made to get rid of these difficulties by

that one adds absorption agents to the cellulose, such as e.g. kaolin, thereby reducing the saramen stickiness of the resin, which is secreted. This, however, does not prevent the precipitation of the resin itself, apart from the fact that with many types of paper, the addition of kaolin is undesirable.

According to US Patent No. 3,748,220, aminopolycarbonic acids are used as agents to combat resin formation, in particular nitrolotriacetic acid in combination with water-soluble polyacrylates. As appears from this patent document, tests in practice have shown that the aforementioned organic complex formers alone or in a mixture with tripolyphosphate have not shown any effect. Only mentioned together with polyacrylates could a resin discharge be prevented. In addition, attempts have already been made to add alkali polyphosphate ". for the same purpose whose solution is set to a pH value between 5 and 8, as appears from the German patent document no. 740 833.

Finally, attempts were also made to overcome difficulties with resin by means of finely divided magnesium silicates.

The US patents 3,733,270 and 3,451,939, which include the use of phosphoric acids alone or in combination with polyphosphates to prevent lime deposits in tap water, thus make the present invention not obvious, as it is known that the prevention of resin deposits does not constitute the problems that are directly related to complex formation, especially with calcium ions.

The aforementioned aids can only conditionally prevent resin deposits, and they then fail when particularly problematic operating conditions exist, such as e.g. extremely poor water conditions, high temperatures or unusual pH ranges.

It has now been found that, even in extreme cases, resin secretion can be prevented if, during the production of the fiber suspension, before feeding it to the paper machine, phosphonic acid compounds of the general formula are added to the resinous cellulose or abrasive

in which"

alone or together with aminopolycarboxylic acids and/or hydroxy acids or their alkali metal salts in amounts of

0.02 - 1.0%, calculated on dry matter, or instead of or in addition to aminopolycarboxylic acids and/or hydroxy

acids use orthophosphoric acid and/or polyphosphoric acids or their alkali metal salts.

Connections of this kind are e.g. aminomethanediphosphonic acid, aminotrismethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, propylenediaminetetramethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, 1,2-cyclohexanediaminotetramethylenephosphonic acid, 1-aminomethylcyclopentylamine-(2)-tetramethylenephosphonic acid, N-phosphonomethane-l-aminoethane 1,1-diphosphonic acid, acetamidino-ethane-diphosphonic acid. As nitrogen-free compounds, 1-hydroxyethane-1,1-diphosphonic acid and 1-hydroxypropane-1,1,3-triphosphonic acid in particular have proven effective. Suitably according to the invention, carboxyalkane-amino-alkanephosphonic acids can also be used, such as e.g. bis-N-carboxymethane-aminoethanediphosphonic acid or phosphonobutanetricarboxylic acid.

From the group of hydroxy acids, particularly gluconic acid, citric acid and tartaric acid are applicable.

From the range of aminopolycarboxylic acids, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) and nitrilotriacetic acid (NTA) are particularly relevant.

The mentioned phosphonic acids alone show a very good effect. However, their effect is enhanced in connection with the hydroxy acids and/or aminopolycarboxylic acids, this effect goes far beyond the synergistic effect.

It has further been found that in addition to or instead of the aminopolycarboxylic acid and/or the hydroxy acid or their alkali metal salts can use orthophosphoric acid and/or polyphosphoric acids or their alkali metal salts with equally good resp. even better results.

Most advantageously, a combination of the aforementioned phosphonic acids and acid or neutral salts of orthophosphoric acid is suitable. The mixing ratio can fluctuate within wide limits and is in the range of 10:1 - 1:10. A very favorable ratio of the active substances, seen from an economic point of view, is 1 part phosphonic acid: 4 parts phosphoric acid, calculated as 100%<1>ig substance.

From the series of polyphosphoric acids or their salts, all compounds can be used, which correspond to the general formula <H>n+2 <P>n °3n+l' whereby n is approx. 2-60. Connections of this kind are e.g. diphosphoric acid, triphosphoric acid, tetraphosphoric acid and medium- to high-molecular-weight polyphosphoric acids or their alkali metal salts.

In the practical application, the active substances can be added alone or in a pre-prepared mixture to the starting material.

The addition can be made in different places in practice. During cellulose production, the corresponding agents can already be added to the cooking acid, the wood chips or during the washing process or during bleaching. During the production of abrasives, resin-preventing agents can be added to the abrasive water or the newly prepared abrasives.

In papermaking, one will follow the place with the greatest resin secretion for the most favorable time for the addition. Usually, the addition takes place in Dutchers or in the mixing device, but it can also take place in one of the vessels or in the mass collection box, depending on the production conditions.

The pH values of the pulp can e.g. remain at a constant value between 4.5 and 8. Under certain circumstances, these values can be shifted further up or down.

As clear comparisons, examples 5-7 were carried out at a pH value of 7.

In a similar way, dispersing or wetting substances can also be used to enhance the effect,

e.g. alkylphenol polyglycol ether.

The necessary amounts of additives according to the invention are between 0.02 - 1.0%, especially 0.04 - 0.3%, calculated on the dry cellulose-containing material.

If a mixture of phosphonic acids, polyaminocarboxylic acids and hydroxy acids is used, resp. their alkali metal salts, so

the mixing ratio can be varied within wide limits. A mixture in which the phosphonic acid is in a ratio of 1:6 - 6:1 to the other components has proven to be very advantageous. Particularly preferred are amino-lower-alkanephosphonic acids with 2-6 G atoms in the carbon chain, DTPA and gluconic acid including the alkali metal salts in the aforementioned mixing ratio.

To show the superiority of the method according to the invention

in simple comparison experiments, the methods according to Gustafson were used, which are described in detail in "Papper og Tro", No. 4a, pp. 121-128 (1952).

In this publication it is mentioned that the resin difficulties become greater as the pH value of the phase suspension increases, i.e. they are less at a pH value of 4.5 than at a pH value of 7. For this reason, the comparison experiments were carried out at a pH value of 7 under modification of the above-mentioned method, so that instead of a copper apparatus a beaker was used,

which contained a copper stirrer. (Svensk Papperstidning 59,

No. 9 (1956), 324).

COMPARISON EXPERIMENT

a) In a laboratory Dutch, loo g was not particularly resinous, but tending to resin separation, unbleached cellulose

added 2.4 1 water and defibrated without paint. The thus produced fiber suspension was filled into a 3-1 beaker and adjusted to a pH value of 7 by adding NaOH or in HC1. It was then stirred for two hours with a cleaned copper laboratory stirrer. Then the resin, which had separated on the stirrer, was dissolved and determined.

1. To a cellulose solution, which was prepared in the above manner, was added o.3 g (=o.3%) graham salt (NaP03).H20

dissolved in lo cm"^ of water for the impact.

2. The work was carried out in the same way as under 1, but instead of graham salt, tetrasodium pyrophtate (^^20^) was used. 3. Instead of Graham salt, diethylenetriaminepentamethylenephosphonic acid was used in this experiment, which was adjusted to a pH value of 9 with caustic soda. 4. Instead of Graham salt, ethylenediaminetetramethylenephosphonic acid was used in this experiment, which was adjusted to a pH value of 9 using caustic soda.

All comparison experiments were each carried out twice at 2o°C and at 45°C. The determination of the resin, which had separated on the copper converter, gave the following values:

As these test trials show, the resin secretion can be reduced by the addition of the mentioned phosphonic acids by 60 - 70%, while the other additions give a significantly smaller reduction in the resin secretion. b) A similar trial was carried out with special resinous cellulose.

200 g of particularly resinous cellulose was beaten up into a 4% phase suspension in a mixing device.

This suspension was divided into two portions, each containing 100 g of cellulose, to determine the resin secretion with and without addition according to the method described above.

As an addition, 0.2 g of a solution was used, which contained 0.04 g of diethylenetriaminepentamethylenephosphonic acid,

o.o39 g sodium gluconate and o.o27 g diethylenetriaminepenta-acetic acid and which was adjusted to a pH value of 9.1 with caustic soda.

The proportion of secreted resin was without addition 340 mg/loo g cellulose, with the specified addition it could be reduced to 95 mg/loo g cellulose.

As the following examples show, it has been shown in many practical trials that the agents according to the invention are even more effective under production conditions than in laboratory trials.

EXAMPLE 1

j

a) In a Dutch, per filling 9,600 1 water and 400 kg of a mixture of 30 parts bleached sulphate cellulose and 50 parts

bleached sulphite cellulose and 20 parts unbleached sulphite cellulose used and ground to a grinding degree of 35° SR. Then 12 kg of commercial partially saponified resin glue and as much aluminum sulphate are added until the substance exhibits a pH value of 4.8.

From this material, a paper of 30 g/m 2 was produced on a long-term paper machine over 24 hours, i.e. for 24 hours the same type of paper was produced. Already after the first hour, resin difficulties arose on the paper machine, this was shown by small resin spots forming on the machine screen, these caused many small holes in the paper, so that the paper was unusable and had to be partly taken back into production as scrap. The machine was then switched off and the sieve cleaned with carbon tetrachloride. This course repeated three times in the course of 24 hours. b) in the same way as under a), a paper material was produced, to which after grinding was added a mixture of 0.12 kg of diethylenetriaminepentamethylenephosphonic acid, 0.68 kg of sodium gluconate and 0.24 kg of diethylenetriaminepentaacetic acid as 40%'-ig solution, which was set to a pH value between 9-9.5 with KOH and the whole thing became in the course of approx. lol my well mixed in a Dutchman.

So much cellulose was produced in the indicated manner that the below

a) said type of paper could be produced in four days. In the course of this entire trial period, there was no downtime and no

to some paper breaks, the finished paper was free of holes

and it produced no wreckage, which had to be taken back into production. Visually, there was no resin to be seen on the paper machine. In this case, no other known resin-preventing agents had shown such a result.

EXAMPLE 2

a) Unbleached sulphite cellulose was placed in a mixing device and brought to a grinding degree of 5o° SR in the refiner. This

the cellulose was mixed with separately prepared abrasive compound and kaolin in the mixing vessel in a ratio of 30 parts cellulose, 55 parts

abrasive compound and 15 parts kaolin.

After the addition of 2% commercial, reinforced resin glue, the pH value of the mass was adjusted to 4.5 by the addition of aluminum sulfate.

From this mass, a paper of 80 g/m 2 was produced. In a period of 8 - 12 hours, the paper broke. After cleaning the paper machine sieve, the paper breaks stopped, only to occur again after a couple of hours. b) In a new trial series, the pulp, which was prepared according to a), was added after grinding as a resin inhibitor with ethylenediaminetetramethylenephosphonic acid, so that at a mass flow of 4o kg/min. was continuously added at 2o g/min. ethylenediamine-tetramethylenephosphonic acid sodium in the form of a 25% solution using a dosing pump in the pulp line, which corresponds to o.o5% calculated on dry paper pulp.

With this working method, no resin difficulties occurred, even over several weeks.

EXAMPLE 3

250 kg of bleached sulphite cellulose, which was known to gradually cause resin difficulties, was milled in Holland at a bulk density of 3% to the parchment threshold. The pH value of the mass was 6.o.

Before the painting was started, about 0.5 kg of sodium salt of phosphonobutane tricarboxylic acid was added to the mass in the Dutchman and about 8 kg after the painting was finished.

After the introduction of these precautions, there was none

in the hoIlender walls or in the pipelines or on the paper machine resin secretions.

EXAMPLE 4

In a Dutcher, 3.8oo 1 of water, 12o 1 of unbleached and 8o kg of bleached sulphite cellulose were introduced and this was ground to 4o° SR.

Before painting was started, 3 kg of a 10% solution of a sodium polyphosphate with an average degree of condensation of 8 - 0.5 kg of a 20% solution of the sodium salt of N-phosphonomethylene- 1-amino-methane-1,1-diphosphonic acid.

After the painting and gluing with 4% resin glue, the pulp was drained from the Dutcher into the pulp vessel and the whole process was repeated in the Dutcher. All the pulp was then processed into paper on the paper machine. Although it was known that the cellulose used caused handling difficulties, which were particularly noticeable with paper breaks and holes in the paper, none of these disadvantages were observed during the entire experiment.

EXAMPLE 5

Without addition:

From a sulphite cellulose, which was known to cause resin difficulties on the paper machine, the total resin content was determined by extraction with dichloromethane and a content of 0.448% was found.

The proportion of harmful resin was 8.7% of the total resin. The determination of the resin proportions is carried out in the following way: 10 g of the aforementioned type of cellulose was broken up into a 4% suspension in water. This pulp suspension was circulated in a laboratory dutch oven without grinding for two hours. The working temperature was 40°C, the pH of the suspension 7. To collect the resin released from the cellulose, a pre-cleaned brass can was suspended into the circulating pulp. At the end of the experiment, the pulp was emptied out of the laboratory dutchman, the dutchman and the tin was washed with water. The resin, which had been secreted on the walls of the Dutchman and on the metal parts son had stuck into the pulp, was collected using cellulose wadding which had been moistened with dichloromethane, and the wadding was extracted with dichloromethane. The tin was washed several times with dichloromethane. All portions of dichloromethane from the extraction and wash liquor were pooled, evaporated and the remaining resin weighed out. O.o391 g of resin was found, which corresponds to 8.7% calculated on

the collected resin.

EXAMPLE 6

Cellulose of the same kind as in example 5 was prepared in the same way and added for the circulation time with 0.5% of a solution of

4 parts phosphoric acid, 75%

3 parts ethylenediaminetetramethylene-

phosphonic acid, 18%

the whole was adjusted to a pH value of 7 with caustic soda, 50% and further processed in the same way as in example 5.

The proportion of harmful resin that was found was 0.05%, calculated on cellulose, (3.35% of the total resin proportion).

EXAMPLE 7

This experiment was carried out analogously to the experiments in examples 5 and 6.

As a resin inhibitor, 0.5% of a solution of 17 parts of diethylenetriamine-pentamethylenephosphonic acid (37%

23 parts phosphoric acid (75%)

everything is adjusted to pH 7 with lye (50%)

added at the beginning of the orbital period.

The resin that was secreted in the course of the experiment was 0.012%, calculated on the cellulose used (2.5% of the total resin content).

EXAMPLE 8

;In a Dutchman, 3,800 1 of water, 12o kg of unbleached and

80 kg of bleached sulphite cellulose and ground to 4o°SR.

For the beginning of the painting, the fiber mixture was added

3 kg of a 10% solution of a sodium polyphosphate, whose average composition corresponds to the formula NaioP8025°^ °' ~* ^9

of a 20% solution of the sodium salt of N-phosphonomethylene-1-aminomethane-1,1-diphosphoric acid.

After painting and gluing with 4% resin glue, the mass became

empty from the Dutchman to the pulp vessel. This way of mass storage is often repeated until the material requirement for a 2-day paper production was covered. The collected pulp was then processed into paper on the paper machine. Although the cellulose used was known to cause resin difficulties,

which in particular appeared as paper tearing and holey paper, no such disadvantages were observed during the trial.

The significant reduction of resin excretion, which is proven

in previous examples, are in practice sufficient to

remove the usual resin difficulties in papermaking.

Claims (2)

1. Method for preventing resin excretion in the production of paper, cardboard and cardboard, characterized in that during the production of the fiber suspension, before feeding to the paper machine, phosphonic acid compounds of the general formula are added to the resinous cellulose or abrasive compound: in which alone or together with aminopolycarboxylic acids and/or hydroxy acids or their alkali metal salts in amounts of 0.02 - 1.0%, calculated on dry substance mass, or instead of or in addition to aminopolycarboxylic acids and/or hydroxy acids use orthophosphoric acid and/or polyphosphoric acids or their alkali metal salts. 2. Method according to claim 1, characterized in that one uses o.o4 ^ o.3% of the compounds according to claim 1.