NO166805B - HYDROPHOBABLE AGENT FOR CELLULOSE FIBER, PROCEDURE FOR THE PREPARATION OF THIS AGENT AND USE OF THE AGENT FOR MASS HYDROPHOBERATION. - Google Patents

Description

The present invention relates to a hydrophobing agent consisting of an emulsion/dispersion of a finely dispersed hydrophobic material in a fan phase for use in gluing organic cellulose fibres, in particular in papermaking and in particular in mass hydrophobing (gluing) during papermaking, as well as a method for producing the agent and the use hence. Gluing or hydrophobing paper is an old technique originating in China. When the papermaking technique came to Europe, absorbent paper was found to be less suitable for the pens and inks of the time. As early as the 14th century, gelatin was therefore added to papers to obtain a hard,

dense, non-absorbent paper. The gluing technique with gelatin and starch has subsequently been gradually improved.

At the beginning of the 19th century, gluing technology was revolutionized by the introduction of resin glue. In resin bonding, resin is precipitated using alum in the fiber suspension before the sheet is formed. The precipitate formed is cationic and associates with the negatively charged fibers. The aluminum resinate that is formed in the reaction is very water-repellent (hydrophobic) and produces a paper product with little wetting properties. The mass bonding technique with resin glue/alum remained relatively unchanged for the first 150 years. Later, the resin acid has been modified by bringing it to

to react with, for example, maleic anhydride and fumaric acid (so-called reinforced resin glue). In order for the glue to become water-soluble, the resin acid was mixed with caustic soda and diluted before dosing.

An improvement of the latter technique was made on

The 1960s and 1970s, when so-called dispersion adhesives began to be used. This technique involves dispersing the resin acid into small anionic particles (0.2-0.5 µm) in a water solution. The dispersion thus obtained is stable and is added to the mass and combined using alum.

However, despite some innovation during various stages, the resin bonding technique has been fundamentally similar to the technique used in the 19th century, i.e. two components are required to achieve bonding, i.e. part resin adhesive, part a precipitation chemical, which is based on an aluminum salt such as alum.

In GB-A1-2010352, another pulp bonding method is described in which a resin adhesive consisting of a treated resin acid is added to the pulp and then bonded to the fibers by adding a practically sulfate-free aluminum polyhydroxychloride to the pulp which is mixed with the resin glue. The advantage of using this special precipitant is stated to be less corrosion problems compared to alum as a precipitant. However, the gluing process uses a two-component system, whereby the usual precipitating agent alum is replaced with another precipitating agent in the form of a special aluminum salt.

German patent 363,668 also discloses a two-component system in which a resin adhesive compound is combined with a neutral or basic aluminum chloride.

In addition to the resin gluing technique, a similar gluing technique has been utilized using neutralized tall oil fatty acids (see for example Swedish patent 7507128-2 with publication number 416 831) which is also used with an external precipitating agent such as alum.

A major disadvantage of the known gluing methods is that the hydrophobic effect decreases dramatically when the paper systems are neutral or alkaline. This is a particularly big problem when you want to use calcium carbonate instead of clay as filler, as the calcium carbonate dissolves at low pH. This deficiency in conventional gluing stems from the fact that cations of aluminum are needed to precipitate the negatively charged resin acid/fatty acid. In neutral or alkaline systems, aluminum ions combine in the form of aluminum hydroxide, which is a poor precipitant for resin glue, and you therefore get a low degree of bonding in this case. This limitation is a particularly serious problem when gluing in neutral or alkaline pulp systems, as from both qualitative and cost points of view it is preferred to use calcium carbonate instead of clay as a filler, for example for fine paper.

In addition to the usual resin sizing systems, new synthetic adhesives have also been developed which have gained ground in papermaking at neutral or alkaline pH. Examples of adhesive compounds of this type are alkyl succinic anhydride and alkyl ketene dimers. However, these glues have a significantly higher price than natural glue compounds such as resin acids and fatty acids. Another disadvantage of these known synthetic adhesives is that they require a longer time to achieve the desired adhesive effect compared to the curing time for resin acid-based or fatty acid-based adhesives. The longer time for the synthetic glue means that the paper immediately after production does not have completely water-repellent properties after the drying stage.

A longer curing time entails disadvantages for surface gluing and/or surface coating of the paper directly after pre-drying. With a low degree of gluing (when using alkyl ketene dimer gluing), the paper is therefore often excessively rewetted, which can cause web breakage and reduce productivity. Furthermore, gluing with such neutral gluing systems can lead to low paper friction as well as coating problems in various parts of the paper machine system. These production problems have therefore been one of the reasons why resin bonding in acid pulp systems containing clay as a filler is still the dominant hydrophobization technique. Another reason is the significantly higher price for synthetic adhesives compared to the price of resin acid or fatty acid-based adhesives.

British patent 1 107 717 has also proposed gluing systems comprising an emulsion of paraffin wax as dispersed phase and a water solution of basic aluminum chloride as continuous phase, whereby the emulsion was stabilized with non-ionic emulsifiers and/or non-ionic thickeners. As examples of hydrophobic materials other than paraffin, microcrystalline waxes, polyethylene and similar waxes, high-molecular fatty alcohols and high-molecular fatty amides have been indicated, but not exemplified. However, it has been shown that such gluing systems have not produced the intended effect. The same applies to the gluing system indicated in British patent 1 274 654, which is also based on a combination of the same compounds. Common to the gluing system according to these two patents is that the paper that is glued with the system has a mottling which is a sign of uneven distribution of the adhesive compound.

A disadvantage of known gluing systems is also that they are adapted for use either in acidic pulp systems or in neutral and basic pulp systems. This causes difficulties for paper use, which will transition from, for example, acidic pulp systems to neutral or basic ones. The conversion involves a change in several interrelated factors, where transitions from one adhesive system to another entail significant difficulties in running in. There is therefore a need for an adhesive system that can be used in both acidic and neutral or basic mass systems, as the conversion problems would then be significantly reduced.

A main aim of the present invention is therefore to provide a pulp hydrophobic agent which avoids the limitations of conventional technique. Another purpose of the invention is to provide a hydrophobic agent which can be used as a one-component agent without the need for separate addition of precipitation chemicals. Another object of the invention is to produce a method for producing such a new hydrophobic agent. A further aim of the invention is to provide a gluing system which can be used in both acidic and neutral and basic mass systems.

The invention is based on the surprising discovery that it is possible to produce a stable one-component agent which is usable as an adhesive compound and which does not require any external precipitating agent (which, on the other hand, conventional resin-based or fatty acid-based adhesives require), if you combine certain polyaluminium salts, one or more resin acids and/or fatty acids, optionally in admixture with a melting-point-reducing additive such as paraffin or other hydrophobic melting-point-reducing agent, and preferably also a cationic organic compound with a low pH (less than 4). This adhesive compound consists of small emulsified (dispersed), strongly cationized particles, which will be directly adsorbed on the negatively charged fibers when dosed to the paper system or when applied to other organic fibers.

The hydrophobicizing agent according to the invention is characterized by the fact that the finely dispersed material consists of resin acid and/or fatty acid and that the water phase contains an aluminum salt consisting of a polyaluminium chloride and/or a polyaluminium sulfate.

The hydrophobizing agent is produced by forming a water solution of an aluminum salt consisting of a polyaluminium chloride or a polyaluminium sulfate, and which is preferably also made to contain a cationic, organic compound, and that the resin acid and/or fatty acid is then emulsified/dispersed as a finely dispersed phase in the water solution. The invention also relates to the use of this hydrophobing agent for mass hydrophobing of cellulose fibers in papermaking.

One of the advantages of the invention is that the polyaluminium salt and the resin acid and/or fatty acid are combined at low pH (less than 4), whereby a direct activation will occur when the hydrophobing agent is brought into the mass and a precipitation of a compound of aluminum and resin and/or fatty acid is formed , when the emulsion drop enters the pH range 4-6. With the invention, a close contact is achieved between the resin acid and/or the fatty acid and the polyaluminium salt, so that despite the high pH during paper production, the aluminum hydroxide does not have time to precipitate before the formation of the active resin acid/fatty acid resinate. Another advantage of the hydrophobizing agent according to the invention is that the small emulsified/dispersed particles, due to their small size, will optimally cover the surface to be hydrophobized.

A very big advantage of the invention is that no external precipitating agent is required when using it. This means a great simplification for those who want to carry out a hydrophobing, especially in papermaking, not only because only one compound has to be added, but also because a more secure and uniform gluing is achieved, as it is easier to optimize the amount of addition by application of a one-component adhesive according to

the invention than when using ordinary two-component adhesives.

At present, the biggest advantage, compared to conventional resin adhesives, is considered to be that the hydrophobing agent according to the invention is very effective even at high pH with paper types that contain large amounts of calcium carbonate as a filler.

Another advantage of the invention is that the hydrophobing agent consists of significantly cheaper raw materials than the synthetic adhesives available on the market do. Resin and fatty acids are available in almost unlimited quantities. From a technical point of view, the new hydrophobing agent is also superior to synthetic adhesives (for example alkyl ketene dimers) for neutral or alkaline paper systems, as the hydrophobing agent according to the invention is quick-setting and thus produces a low-wetting paper already on the paper machine. This does not cause the production disruptions that other synthetic adhesives can cause.

In general, the invention entails that a polyaluminium salt, a non-neutralized resin acid and/or fatty acid, possibly in a mixture with a melting point lowering additive such as paraffin, and preferably also a cationic organic compound, is mixed in water under vigorous stirring, whereby an emulsion/dispersion is obtained, which consists of small cationic droplets of the order of 0.05-50 µm, preferably 0.05-25 µm.

The best effect and stability of the adhesive is achieved if the cationic organic compound is included in the adhesive itself. For certain applications, however, it is possible to combine the one-component adhesive (i.e., the resin acid/fatty acid and the special polyaluminum salt) with the cationic organic compound first upon application to the organic fibers. In papermaking, the cationic compound can thus be added separately to the paper pulp either for gluing purposes or for another purpose. Thus, the gluing process according to the invention can be combined with known papermaking processes where a cationic organic compound is added to the pulp, for example the method according to the European patent EP-B1-41056 and the European published patent application EP-A1-80986.

The dispersion/emulsion produced in this way is, especially if it contains the cationic organic compound, so stable and highly concentrated that it can advantageously be distributed to the user in ordinary means of transport.

The polyaluminium salts which have proved most suitable for the purpose of the invention are the basic polyaluminium salts such as polyaluminium sulphate or polyaluminium chloride. These salts are characterized by a high molar ratio between aluminum and counterion (>1) and by the fact that in aqueous solution they give polyaluminium ions with a high charge such as, for example, A11304(OH) 2e(H2°)105+>

The raw materials for the hydrophobizing agent according to the invention can consist of pure resin acids and pure fatty acids or combinations of resin acids and fatty acids, whereby, however, melting point lowering additives such as paraffins can also be mixed in.

When resin acid is used, a typical resin acid composition is the following:

When fatty acid is used and comes from tall oil, the following composition is common:

With the invention, it is possible to use a modified resin acid/fatty acid that is strengthened by reactions with compounds that are common in this context, such as maleic anhydride, fumaric acid, etc.

With the invention, it is important that the constituent resin acids and/or fatty acids are present in uncharged form (non-neutralized form), i.e. that the pH should be kept low, preferably below 5. At a higher pH, negatively charged carboxylate groups are obtained which reduce the cationic character of the emulsion/dispersion droplets (thereby breaking the emulsion/dispersion).

Appropriate amounts of the various components are 0.5-90% resin acid/fatty acid and 10-99.5% water.

A suitable weight ratio between resin acids/fatty acids and aluminum in dispersion is between 100:1 and 1:4, preferably 10:1 and 1:2.

The cationic organic compound included in the water phase can be a surfactant, starch, guar gum, carboxymethyl cellulose, polyacrylamide, polyimine, polyamine, polyamidamine, polyethyleneimine or polyacrylate. A suitable weight ratio between resin acids/fatty acids and the cationic organic compound is between 100:0.01 and 100:30.

In the following, the invention will be explained in more detail with some design examples.

EXAMPLE 1

In this example, a glue emulsion is prepared by mixing 500 g of tallow fatty acid (BEVACID 2 from Bergvik Kemi, Soderhamn, Sweden), which is fortified with 5% fumaric acid, with 2.49 g of a cationic surfactant (hexadecyltrimethylammonium chloride from Riedel-de Haen AG, Seelze-Hannover , West Germany) and 69.9 g of ethanol. This mixture is then put under vigorous stirring (stirring ULTRA-TURRAX from IKA-Werk, Stuten) to a mixture which consisted of 5.61 g of cationic starch with a nitrogen content of 0.4% (starch S-195 from Raisio-SLR AB, Gothenburg, Sweden), 967.5 g polyaluminum chloride.(Al2(OH)5C1.2H2O from Albrigt & Wilson, Ltd., London, Al content 25% by weight) 1 in 4454 g water. The temperature during the mixing process was 25°C for both the fatty acid phase and the water phase.

The mixture was then homogenized in a valve homogenizer (Gualin Lab 60, APV Schroeder, Luebeck, West Germany) at 350 bar overpressure. The pH of the emulsion formed was measured at room temperature and was 3.7. When examined under a microscope, it was determined that the produced adhesive had an emulsion droplet size of approx. 1-2 µm.

The emulsion formed was stable against phase separation for more than 2 months.

EXAMPLE 2

25 g of a mixture of 55% tall fatty acid and 45% tall resin acid (special fraction from the distillation plant of Bergvik Kemi AB - the fraction was fortified with 10% fumaric acid) was added in the same way as in example 1 to a mixture of 24 g of polyaluminium chloride (same as in example 1) and 0.063 g of cationic polyacrylamide ("PERCOL" 181 from COM, Vestre Frølunda, Gothenburg) and 250 ml of water. Otherwise, the preparation was carried out in the same way as in example 1, and the result was a stable dispersion with a small particle size and pH approx. 2.5.

EXAMPLE 3

In this example, a stable dispersion was prepared by adding 1.7 g of unfortified tallow resin acid ("BEVIROS SG" from Bergvik Kemi AB, Soderhamn) to 16.7 g of water containing 0.02 g of cationic surfactant (hexadecyltrimethylammonium bromide from Riedel-de Haen AG, Seelze-Hannover, West Germany) and 1.6 g of polyaluminium chloride (same as in Example 1).

The mixture was transferred to a 100 ml pressure vessel and heated to 148°C on a hot plate under magnetic stirring. After 30 minutes, the heating was interrupted and the dispersion was allowed to slowly cool to room temperature. The pH of the product obtained was 2.8.

EXAMPLE 4

0.13 g of cationic surfactant (dissolved in 3.5 g of ethanol) was added to 50 g of a mixture of fatty acid/resin acid (the same fraction as used in example 2). The cationic surfactant was the same as in Example 3.

The fatty acid/resin acid mixture was added to 148 g of water containing 48.4 g of polyaluminium chloride (same as in the previous example) and 0.25 g of cationic starch, which had a nitrogen content of 0.4%. Otherwise, the manufacturing process was the same as in examples 1 and 2.

In this experiment, a stable dispersion was obtained which had a pH of 2.5 and which had a somewhat higher viscosity than the dispersion in previous examples.

EXAMPLE 5

In this example, 25 g of fatty acid/resin acid (same fraction as in example 2) was added to 250 ml of water containing 0.6 g of cationic guar gum (nitrogen content 1.5%, "GENDRIVE 162" from Henkel Company, USA) and 150 g of polyaluminum sulfate (the polyaluminium sulphate was purchased from Boliden Kemi AB, Helsingborg and contained 15.5% aluminum and 65% sulphate, i.e. had the molar ratio A1:SO4 = 0.9).

The manufacturing process was otherwise the same as in that

previous example. The pH of the dispersion was 2.5. The experiment showed that the fatty acid/resin acid could be combined with the other components, i.e. so that a dispersion was obtained. The dispersion's stability against phase separation was nevertheless lower (1 day) than in previous examples.

EXAMPLE 6

1.25 g of cationic starch with a nitrogen content of 0.40% and 4.86 g of polyaluminium chloride (see previous example) were dissolved in 250 g of water at 95°C. 25 g of tallow fatty acid (same as in example 1) was heated to 95°C and added continuously to the hot water solution using the previously described methodology.

The obtained emulsion had a pH of 2.5 and contained emulsion droplets with a size of 3-4 µm. The emulsion proved to be stable against phase separation for 8 days.

EXAMPLE 7

In this experiment, a stable lime emulsion was produced by adding 25 g of tallow fatty acid ("BEVACID 2") to 250 g of water containing 5.6 g of cationic starch with a nitrogen content of 0.40% and 29.2 g of polyaluminium chloride. Otherwise, the same conditions were used as in example 1. The obtained emulsion pH was 2.8.

EXAMPLE 8

25 g of a special fraction of fatty acid/resin acid (same product as in example 2) was added to a solution in the manner indicated in example 1, which consisted of 58.3 g of polyaluminium chloride (same as in example 1) and 216.7 ml of water. The preparation was otherwise carried out as in example 1, whereby a stable emulsion/dispersion with pH 2.8 was obtained.

EXAMPLE 9

In this example, 25 g of a mixture of fatty acid/resin acid (same as in example 2) was added to a solution of 58.3 g of polyaluminium chloride (same as in example 1) and 91.7 g of water, whereby the same methodology was used as in example 1. After cooling in a water bath, 125 g of a 1% solution of cationic starch (nitrogen content 0.40%) was mixed into the product formed above. The result was a stable emulsion/dispersion with pH 2.8.

EXAMPLE 10

A pulp with the following composition was produced:

70% fully bleached chemical pulp (60/40 birch sulphate/tall sulphate) 3 0% calcium carbonate ("Seahorse" from Malmøkrita).

The birch and tallow sulphate were collected in laboratory flasks to a grinding level of 200 ml CSF (Canadian Standard Freeness). The calcium carbonate (slurried in water) was added and the mass diluted to 0.5% solids content. The pH of the mass was 8.0.

In the experiment, different quantities of partial adhesive according to example 1 were dosed, partly a conventional resin glue ("T-lim 7635" from Hercules AB, Gothenburg) to different batches of the paper pulp.

In the experiments with the conventional resin glue, 2% alum (calculated in relation to dry mass) was added in the usual way before dosing.

The adhesives were dosed in the form of 1% solutions and added to the 0.5% mass while stirring (45 s). The pulp was then transferred to a laboratory sheet form (Finnish form) with 100 mesh wire. The sheet formation was carried out according to SCAN C 26:65 (basis weight was 73 g/m<2>). The sheets were dried at 23°C and 50% relative humidity overnight, after which the sheets were placed in a heating cabinet (30 minutes) at 120°C.

After conditioning (23°C, 50% relative humidity) the water absorption capacity was determined according to SCAN P 12:64 (Cobb60)•

Table 1 shows the results of the survey. The dosed quantities of the adhesives (percentage by weight) indicate the amount of addition

(active content) calculated in relation to dry mass. From table 1 it appears that the adhesive according to the invention gives a perfectly good bonding (Cobb60<25) despite high pH and large amounts of calcium carbonate.

EXAMPLE 11

A paper pulp was produced in the same way as in example 10. The resulting pulp had a pH of 7.3. Various adhesives according to the invention were added to the mass.

Sheet formation and drying of the paper sheets was carried out in the manner indicated in Example 8. Water absorption according to Cobb<6>0 (SCAN P 12:64) was determined. The results are shown in table 2.

EXAMPLE 12

In this experiment, a pulp from a journal paper mill was used. The mass concentration of the pulp was 3% and the pulp was ground to a grinding grade of 125 CSF. The composition of the mass used was:

22% fully bleached chemical pulp

15% TMP (thermomechanical mass)

35% abrasive compound

28% faulty goods

30% kaolin (C-clay from ECC) was added to the pulp, calculated in relation to theoretical dry fibre. The mass was diluted to 0.5% concentration and the pH adjusted to 5.0.

The adhesive produced according to example 3 was dosed in different amounts to the suspension of fibers and filler. Sheets were produced according to SCAN C 26:67 (basis weight 73 g/m<2>).

In this experiment, the sheets were dried on a dryer at 85°C. The sheets were then placed in an oven (120°C) for 30 minutes.

After conditioning (23°C, 50% relative humidity), the water absorption capacity according to Cobbg<0> was measured. The results of these measurements are shown in table 3.

EXAMPLE 13

In this experiment, a paper pulp was used which had a dry matter content of 1.37% and a grinding degree of 200 ml CSF and which consisted of 60% birch sulphate pulp and 40% tallow sulphate pulp.

30% calcium carbonate (Malmøkrita "SJØHESTEN") calculated on theoretically dry fiber was added to the paper pulp. The pH was then adjusted to 8.5. An adhesive prepared according to example 1 was added to the mass in different amounts. Sheets were then produced according to SCAN C 26:67 and with basis weights of 73 g/m<2>. The sheets were dried and examined according to what is indicated in example 10, whereby very good gluing was obtained. The bonding results are given in Table 4.

EXAMPLE 14

In this experiment, the same paper pulp and the same method as in example 10 were used. However, an adhesive substance according to example 8 was used as a hydrophobic agent. This was dosed in different quantities, during which 0.6% cationic starch (calculated on theoretical dry mass) was added 15 seconds after the adhesive dosage to act as an external retention agent. The results from the tests appear in table 5. From these tests it appears that the adhesive according to example 1 gave an improvement even without a cationic compound, but that the improvement was more pronounced when the cationic compound was added.

EXAMPLE 15

In tests according to this example, a pulp was used which was produced in the manner indicated in example 10. The same procedure as in example 10 was used for the gluing, but in the present example an adhesive was used instead which was prepared according to example 9. Perfect gluing was also achieved in this experiment, the result of which is shown in table 6.

EXAMPLE 16

As a hydrophobic substance for this example, a mixture of 42 g of tall resin (BEVIROS SG from Bergvik Kemi) and 18 g of paraffin wax (melting point 58°C from Malmsten & Bergvall, Gothenburg) was used. This hydrophobic substance was added with vigorous stirring (ULTRA TURRAX from IKA-verk, Staufen) to a mixture consisting of 3 g of cationic starch with a nitrogen content of 0.4%, 144.7 g of polyaluminium chloride solution (KLORHYDROL from Reheis Chemical Ltd., Dublin, Al content 12.5% by weight) and 92.3 g of water. During the emulsification, the temperature was 95°C for all chemicals used.

The emulsion was then further homogenised for 3 minutes at 10,000 rpm, after which it was cooled in a water bath to room temperature.

The pH of the thus produced product was 3.7, and the particle size was approx. 1-2 µm. Stability was good for more than two months.

For testing the adhesive produced in this way, a paper pulp was produced with the following composition: 80% fully bleached chemical pulp (60/40 birch sulphate/tall sulphate) 20% calcium carbonate ("Seahorse" from Malmøkrita).

The birch and tall sulphate were collected in a laboratory dutchman to a grinding level of 200 ml CSF (Canadian Standard Freeness). Calcium carbonate (slurried in water) was added and the mass diluted to 0.5% solids content. The pH of the mass was 8.0.

The adhesives were dosed in the form of a 1% solution and were added to the 0.5% mass while stirring (45 sec.). The mass was then transferred to a laboratory sheet form (Finnish form) with 100 mesh wire. The sheet formation was carried out according to SCAN C 26:67 (basis weight was 73 g/m<2>). The sheets were dried at 23°C and 50% relative humidity overnight, after which the sheets were placed in a heating cabinet (30 min.) at 120°C.

After conditioning (23°C, 50% relative humidity) the water absorption capacity was determined according to SCAN P 12:64 (Cobb60)•

Table 7 shows the results of the assessment. The dosed amounts of the adhesive (percentage by weight) are the additive amounts

(active content) calculated on dry mass. From table 1 it appears that the adhesive according to the invention gives a perfectly good bonding (Cobb6Q<25) despite high pH and large amounts of calcium carbonate.

EXAMPLE 17

Example 16 is repeated with the same ingredients, but with the following amounts of the different ingredients in the adhesive emulsion:

48 g tall resin

12 g paraffin wax

144.7 g polyaluminum chloride solution

3 g of cationic starch

92.3 g of water

The resulting emulsion had a pH of 3.7, particle size approx. 1-2 um and a good stability over more than two months.

The emulsion was then used for gluing the same pulp as in example 16, and the results of this test appear from table 8.

Claims (14)

1. Hydrophobic agent consisting of an emulsion/dispersion of a finely dispersed hydrophobic material in a water phase, characterized in that the finely dispersed material consists of resin acid and/or fatty acid and that the water phase contains an aluminum salt consisting of a polyaluminium chloride and/or a polyaluminium sulfate. 2. Means according to claim 1, characterized in that the finely dispersed material consists of a non-saponified, preferably reinforced resin acid. 3. Means according to claim 1, characterized in that the aluminum salt consists of a polyaluminium chloride. 4. Means according to claim 1 or 3, characterized in that the molar ratio of aluminum to counter-ion in the polyaluminium compound is above 1:1. 5. Means according to claim 1, characterized in that it also contains a cationic, organic compound. 6. Means according to claim 5, characterized in that the cationic organic compound consists of cationic starch, cationic guar gum, cationic polyacrylamide, polyamine, polyamidoamine or polyethyleneimine. 7. Agent according to each of the preceding claims, characterized in that it contains from 30 to 700 g/l resin acid and/or fatty acid, from 1 to 200 g/l polyaluminium compound, calculated as aluminium, and preferably also from 0.05 to 200g /l cationic, organic compound. 8. Process for the production of a hydrophobic agent, characterized in that a water solution of an aluminum salt consisting of a polyaluminium chloride or a polyaluminium sulfate is formed, and which is preferably also made to contain a cationic, organic compound, and that resin acid and/or fatty acid then emulsified/dispersed as finely dispersed phase in the water solution. 9. Method according to claim 8, characterized in that the material which is dispersed as finely dispersed phase consists of non-saponified, preferably reinforced resin acid. 10. Method according to claim 8, characterized in that the aluminum sulfate consists of a polyaluminium chloride. 11. Method according to claim 8 or 10, characterized in that the molar ratio of aluminum to counterion in the aluminum sulfate is greater than 1:1. 12. Method according to claim 8, characterized in that the cationic organic compound consists of cationic starch, cationic guar gum, cationic polyacrylamide, polyamine, polyamidoamine or polyethyleneimine. 13. Method according to each of claims 8 to 12, characterized in that the dispersion/emulsion is made to contain from 30 to 700 g/l resin acid and/or fatty acid, from 1 to 200 g/l polyaluminium compound calculated as aluminium, and preferably also from 0.05 to 200 g/l cationic organic compound. 14. Use of a hydrophobing agent according to each of claims 1 to 7 for pulp hydrophobing in paper production.