FI107951B - Foaming compositions which affect the strength of a fiber material - Google Patents

Description

107951

Foamy Compositions Affecting the Strength of Fiber Material Skummande sammansättningar som inverkar head hällfasthet av et fibermaterial 5

The invention relates to compositions for treating a fibrous material such as a paper web during papermaking, and in particular to foaming compositions containing additives that affect the strength of the paper. The invention also relates to the use of foaming compounds to increase the strength of the fibrous material.

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It is known to form paper and nonwovens by depositing a slurry of fibers mixed with a liquid, usually mixed with water, onto a carrier known as a porous wire. The wire allows the fluid to flow through it while retaining most of the fiber over the wire in the form of a web or a felt where the fibers are centered on one another and all the fibers are substantially in the plane of the web.

The process presents problems due to the natural flocculation of the fibers, i.e. the tendency to form volatile or compositions that are difficult to disintegrate and can remain in the resulting web, thereby affecting the flatness of the web and its operating properties. This problem is particularly severe when handling slurries that contain long or • high synthetic fibers, such as when making heavy duty webs or when using a paper machine that is naturally slow to drain water. speed is high or when it is important to reduce the drainage of drained fluid ♦ · •. * ·: Cost of education.

The problem of flocculation of fibers can be reduced by breaking the fibers into very large volumes of water. In this case, the fiber concentration is in the range of 10-100 mg / L instead of the generally used concentration of 1-10 g / L. However, handling such large volumes of water is *; · * not commercially viable.

To solve the problem of flocculation, a method has also been proposed in which: the fibers are broken down into a liquid, high viscosity polymeric medium, such as aqueous sugar or luonnonkumiseoksiin. Due to the high viscosity of the medium, it is slow and difficult to drain it through the formed web and the supporting wire, so that the process is not particularly suitable for large-scale continuous production of fiber products.

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U.S. Patent No. 3,937,273 proposes a solution to the problem in which the lip of the paper machine headbox is made very shallow and has a series of sharp bends mounted thereon. As the fiber slurry passes through the lip fractures, the slurry generates very strong turbulences on the slurry which disintegrate the formed volatiles or compositions. The slurry then enters the other shallow lip and passes directly onto the wire and the paper web is formed as usual in a paper machine.

GB-1209409 describes a process for producing a uniform fibrous slurry to a foam which is obtained by breaking up water in the presence of a foaming additive. Such foams are relatively easy to drain and do not unduly restrict paper machine productivity. The advantageous rheology of the foams is believed to be the result of the pseudoplastic behavior of the tightly packed high-strength bubbles in the foam, which limits the movement of the fibers and thus prevents the formation of flowing or compositions, while allowing good and rapid drainage of the slurry.

GB-1129757 discloses a method and apparatus for forming a fibrous web from a foamable medium. The chemical nature of the surfactant is not important provided that it has sufficient foaming power to produce a thick viscous foam formed by very small air bubbles. The surfactant may be anionic, cationic, or nonionic. In the method, a fiber product can be made by breaking the fibers to foamed liquid medium produced by the very decomposition of air into small water bubbles containing a surfactant. The disintegration is carried out with strong shear to achieve the desired properties. The publication emphasizes that the foamed liquid medium must have an air content of at least 65% by volume.

• · · 3 107951

GB-1329409 discloses improvements to increase web flatness. The method shows the effect of the air content of the foam on the behavior of the fibers in the foamed medium. The fibrous material can be made using a foamed liquid medium at an air content of greater than 65%, and there is an air content level at which the fiber-foamed liquid medium tends to accumulate, although very uniformly dispersed in the foamed liquid medium. Furthermore, the size distribution of the bubbles of the foamed liquid medium is of considerable importance. According to the publication, all foamed liquid media produced by bubbling gas into a liquid containing a surfactant are not usable for fiber disintegration, but some foamed liquid media may be used to stack fibers (and particles) rather than disintegrate fibers. The phenomenon can be utilized to improve the retention of certain materials in the web. Further according to the disclosure, when the foamed medium contains gas in a volume percentage of 55-75%, the fibers are dispersed substantially uniformly and uniformly through the foamed liquid medium. When the volume fraction of the gas is less than 55%, the gas is contained in the foam in relatively small bubbles having a relatively wide size distribution and distributing the medium into the fluid pockets where the fibers accumulate. Due to the relatively low viscosity of the fluid, the fibers can move freely and thus accumulate in the fluid pockets. When the volume fraction of the gas is greater than 75% and the size distribution of the bubbles is remarkably uniform, the bubble packing density is such that the bubbles change from their normal circular shape to polyhedral bubbles. As the medium contains such bubbles, the surface tension forces are present in the planes between the bubbles, which pull the fibers into the blast lines of the bubbles formed between the bubbles, whereupon the fibers accumulate in line bundles. Although such aggregation occurs to some extent with a shunt volume greater than 75%, on average, fibers in such a foam are more degraded than when water alone is used as a medium. Factors that determine whether or not a particular foamed liquid medium is the disintegration or aggregation of fibers, '* * * * are the number, shape, and size of gas bubbles throughout the medium.

In order to obtain sufficient foam stability, the foaming additive must be relatively high in the fiber slurry in order for the foam to carry the disintegrated fibers from the disintegrator to the wire. Surfactants are believed to interfere with the forces that bind the fibers and thus their presence reduces the bulk density and strength of the paper product obtained by foam printing. This problem may have been mitigated to some extent by the use of higher refinement fiber or by the addition of reinforcing agents. However, it would be most advantageous to be able to reduce the amount of surfactant used.

It is an object of the invention to provide a foam strength enhancing composition of a fibrous material, in particular of a fibrous material, which can be used in paper making by disintegrating the fibers into a foamable liquid medium to obtain a uniformly formed fibrous web. A further object is to use in said composition an easily and sufficiently foamable compound whose foam retention, foam-forming ability, effect on fiber bond strength and other properties are particularly suitable for the manufacture of paper.

The foamable fiber strength composition of the invention, its use in the manufacture of paper or nonwovens, and the method for increasing the strength of a fiber material are characterized in the claims.

It has been found that the objects of the invention can be achieved and the problems of the prior art methods can be avoided or substantially reduced by using the solution of the invention. The composition of the invention comprises a surfactant and a heat- or acid-curable resin such as urea-formaldehyde, melamine-formaldehyde resin or mixtures thereof, water and may additionally contain. *: a cationic acrylamide copolymer. The components are mixed with a sufficiently dilute aqueous solution of the resin, copolymer, surfactant, water and acid.

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The resin, which is preferably an aqueous solution of urea formaldehyde, is added in an amount of 0.5 to 5% by weight, preferably 0.5 to 3% by weight, calculated on the dry weight of the fiber. The urea-formaldehyde resin has a dry solids content of 30-60% by weight, preferably 35-50% by weight, and the molar ratio of formaldehyde to urea is 1.8-3.8: 1. The resin is preferably diluted to 1-5% by weight in aqueous solution. The cationic acrylamide copolymer is added in an amount of 0 to 3%, preferably 0.5 to 1%, calculated on the dry weight of the fiber. The cationic acrylamide copolymer is typically 10-50% in aqueous solution having a cationic strength of 20-100%, preferably 25-80%, and a molecular weight of 10,000. - 300,000, preferably 50,000 - 300,000. The cationic acrylamide copolymer may be prepared from monomers comprising acrylamide or from monomers in copolymeric cationic form, such as quaternary acrylamide alkyl-N-alkylamine, secondary-tertiary acrylamine alkyl-N-alkylamino-acrylamide, primary acrylamide, -alkylamine alkoxide, or secondary or tertiary n-alkylamine alkoxide or primary amine alkoxide.

A surfactant which is an anionic or neutral surfactant such as ethoxylated alkyl sulfate (AES) having an alkyl chain of 12-14 carbon atoms or a salt thereof, an alkyl glycoside or a salt thereof, or an alkenyl succinic anhydride and an alkyl glycoside syn is added to the mixture.

The synthesis product of alkenyl succinic anhydride (ASA) and alkyl glycoside (AG) can be prepared according to Scheme 1 from an alkenyl succinic anhydride having 10-24 carbons, preferably 14-20 carbons, preferably having 8-20 carbon atoms in the alkyl chain, preferably 8-20 carbons. carbon, using a molar ratio of AS A: AG 0.1-10: 1, · · ») preferably 0.75-1.25: 1, at a temperature of 60-100 ° C and under an inert atmosphere, preferably nitrogen. 20 in the atmosphere. The resulting synthesis product can be converted to the corresponding salt by addition of a base, such as sodium hydroxide, until the pH of the mixture is 5-10, preferably 7.

• · · »•« «· 1 1 1 1 1 1 1 1 1 1 1 1 * * * * * * * * * * * c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c. • · · · · · · V · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ···· ··· 1 1 • «2 · 6 107951

Scheme 1 5 / _ / R> VO-χ ^ Ο + / \ _.

> C / Λ 1 “HO 09

AG ASA

10 r / So r / So / 1 0 + ° v / 12 15 Wl ^ Zr Νξι (Χ_ / b 2 o

R 1 = C 1 -C 10 alkyl R 2 = C 1 -C 20 alkanyl • · 20 2 * * • ♦ ♦ ♦ ♦ ♦

Preferably, the surfactant is ethoxylated alkyl sulfate or its Na salt or alkyl • glycoside or its Na salt, which is added in an amount of 0.1-7% by weight, preferably 2-3% by weight, of the dry fiber of the fiber. 25% by weight or sodium salt of the product of the synthesis of alkenyl succinic anhydride and alkyl glycoside, which is added in an amount of from 1 to 30% by weight, preferably from 15 to 25% by weight, or a mixture of the above.

• 9 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · There is an acid such as hydrochloric or acetic acid that can be used to 1 at a consistency suitable for preparation.

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Alternatively, the components of the composition of the invention may also be added separately to the fiber slurry without first being mixed together.

The composition or composition components of the invention are added to the fiber slurry at a suitable point (s) in the process of making paper or nonwovens. The flotation of the mixture is preferably carried out using a high shear force, suitably by means of flotation apparatuses known in the art, by introducing into the mixture an inert gas such as nitrogen or air, preferably air. Thus, in foam-printing processes, the strength of paper or nonwovens 10 can be increased.

Advantages of the composition according to the invention are good foamability and foam resistance. It provides a clear increase in the strength of the paper even at low surfactant concentrations, which further makes the process economical also in so-called. on ordinary paper grades, the use of the composition is not limited to tissue paper.

In the following, the invention will be further illustrated by some preferred embodiments described in the examples, which, however, are not intended to be exclusive. . restrict.

• · · 20 • · · · ·! Example 1 • · · • · · ··· • · " • ··

The alkenyl succinic acid semi-ester (SI) of an alkyl glycoside is prepared from alkenyl. ·: ·. succinic acid and alkyl glycoside using a 1: 1 molar ratio of starting materials. Alkylyl succinic acid (30.10 g, 0.13 mol) is added rapidly to the alkyl glycoside (60 wt% aqueous solution, 66.66 g, 0.13 mol) at 80 ° C and with stirring at 200 rpm. The reaction mixture is allowed to react under a nitrogen atmosphere at 80-85 ° C for four hours at a stirring speed of 200 rpm. The mixture is allowed to cool to room temperature. The Synthesis Product has a mass of 92.44 g, a water content of 24.4% by weight and a mixture of R 1 = C 5 -C 10, R 2 = C 1 -C 15.

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Subsequently, the sodium salt is prepared from the synthesis of SI. To the synthesis product SI (75.8 wt% aqueous solution, 5.0 g or 9.29 mmol) is slowly added an equimolar amount of sodium hydroxide (1.0 M solution, 9.29 mL or 9.28 mmol) while stirring gently with a glass rod. . The resulting synthesis product has a SI salt of 14.3 g and a water content of 53.4% w / w.

Examples 2-8

Aqueous solutions of urea-formaldehyde resin, of the ethoxylated alkyl sulfate (AES) or of the SI 10 Na salt and of the polyacrylamide copolymer (PAM) were prepared in various compositions, which measured foaming and strengthening properties. The results are shown in Table 1. Foaming took place in a 3000 ml beaker, into which was measured 250 ml of aqueous solution which was foamed with a rod mixer. Foamability refers to the volume of foam immediately after mixing at a mixing time of 1 minute. Air content means 15 volumes of air in the foam as a percentage of the volume of the foamed solution. The reinforcing capacity and adhesion were tested by the glass plate method, in which the glass plate is wetted with the desired solution, a damp cellulose sheet is pressed, which is pressed onto the glass plate and the glass plate is freely dried in an oven for about 20 hours. Hydrogen bonds are formed between the damp sheet and the glass sheet and are either reinforced or weakened by chemicals. The effect was tested with a finger feel by gently pulling the sheet out of the glass plate. . ·. after drying. Concentrations are expressed as weight percent of total solution mass.

• · · • · ·: No fibers are included, but the fiber content is assumed to be 1% by weight, according to which the dosage of chemicals per 1 kg of water was calculated.

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Table 1. Foaming and Strengthening Compound of Various Compositions 9,107,951

EXAMPLE Surfactant UF Resin PAM Foam Foam Adhesion / 5 No. Substance Copolymer Volume Air Content Adhesion wt% wt% wt% ml vol 2 0.03 700 64.29 Poor 3 0.03 0.01 700 64.29 Poor 10 4 0.01 0.01 500 50.00 Good 5 0.02 0.01 0.005 700 64.29 Excellent 6 0.5 1500 83.33 Moderate 7 0.1 300 16.67 Poor 8 0 , 2 0.01 900 72.22 Moderate 15 --------------------------------------- -------------------------------------------------- -----------------------------------------

In Examples 2-5, the surfactant was the Na salt of the ethoxylated alkyl sulfate.

In Examples 6-8, the surfactant was the sodium salt of the synthesis product SI.

Example 9 -18 20

Aqueous solutions of urea-formaldehyde resin, of the Na salt of the ethoxylated alkyl sulfate or synthesis product and of the polyacrylamide copolymer (PAM) were prepared with various · · · * · * formulations, which were measured for reinforcing capacity. The results are shown in Table 2.

• ·: The reinforcing capacity was tested by a method of preparing sheets of 60 g / m 2 in accordance with SCAN-C 26: 2, sprayed with about 5 g of the test substance: pinn *: and two sheets facing each other, they were printed, dried and air-conditioned according to the standard. Subsequently, sheet pairing bonding was measured using a TAPPI T 833 pm-94 standard on a Scott Bond Tester, in which the • • · V: side-sided adhesive clip is punched out of the sheet, causing the sheet to split.

·· »V · 30 The unit can read the energy required for plane splitting. Thus the * · ·: ··: effect of chemicals on the fiber-to-fiber binding could be quantitatively determined.

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Table 2. Strengthening Strengths of Different Compositions

Measured by Scott Bond Tester 5 Example Surfactant UF Resin * PAM- Cleavage Agent * Copolymer * Energy w-% w-% w-% J / m2 9 221 10 10 3 96.7 12 3 372 13 3,257 14 2.5 1,118 15 2.5 2,122 15 16 2.5 1 0.5 118 17 20 75.7 18 20 1 84.1. . In Example 9, no chemicals were added between the sheets.

In Examples 10-16, the surfactant was the Na salt of ethoxylated alkyl sulfate.

In Examples 17-18, the surfactant was the sodium salt of the synthesis product SI.

• * · y * = Concentrations are expressed as percentage by weight of dry mass of fiber.

• · · • · · · ·

Example 19 -23 • · · 25

According to SCAN-C26: 2, 60g / m2 sheets of 1 wt% fiber slurry were prepared. To the slurry was added urea-formaldehyde resin, ethoxylated alkyl sulfate or synthesis. Na salt SI and a copolymer of polyacrylamide in various compositions, the strength of which on the solution sheet was measured by a Scott Bond Tester • · 30 and tensile strength. Tensile strength was measured according to the SCAN-P 38:80 standard. Results • i · «· ·;,; are shown in Table 3.

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Table 3. Strengthening Composition in Solution Sheets

Example Surfactant UF Resin1 PAM Cleavage Tensile Material 1 Copolymer1 Energy Strength w-% w-% w-% J / m2 Nm / g 19 334 95.9 20 0.025 0.01 267 77.5 10 21 0.025 0.02 183 75.4 22 0.025 0.01 0.005 193 55.8 23 0.2 174 65.7

In Example 19, no chemicals have been added in the manufacture of 19 sheets.

In Examples 20-22, the surfactant was the Na salt of ethoxylated alkyl sulfate.

In Example 23, the surfactant was the sodium salt of the synthesis product SI.

* = Concentrations calculated from total stock weight; if they are to be expressed on the basis of the dry mass of the fiber, the figures shall be multiplied by 100.

20 Example 4 • · • 1 · • · • ; 1. · 1 wt.% Fiber slurry was made by sheeting by first foaming the slurry at 3000 rpm for four minutes, followed by making the foam 60 g / m 2 · · *. 1: sheets in sheet form according to SCAN-C 26: 2. Sheets measured Scott Bond Bond strength and tensile strength. The results are shown in Table 4.

• · 1 «« «• • • 4« • • • • • • * * * 4 · • 1 · • • • • • • • • • • • • • »«

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• ♦ ·· • «• · 444

Table 4. Strengthening Composition of Foam Sheets 12 107951

EXAMPLE Surfactant UF Resin1 PAM Foam Splitting Tensile # Material1 Copolymer1 Air Content Energy Strength w-% w-% w-% vol% J / m2 Nm / g 24 0.02 0.01 67 237 44, 2 25 0.02 0.02 72 261 42.6 10 26 0.02 0.01 0.005 68 267 53.5 27 0.2 0.01 74 231 51.6

In Examples 24-26, the surfactant was the Na salt of ethoxylated alkyl sulfate.

In Example 27, the surfactant was the sodium salt of the synthesis product SI.

15 1 = Concentrations calculated from total stock weight; if they are to be expressed on the basis of the dry mass of the fiber, the figures shall be multiplied by 100.

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Claims (9)

13 107951 Foamy fiber strength foam composition, characterized in that the composition comprises a heat or acid curable resin or mixtures of resins, a surfactant and water, and optionally a cationic acrylamide copolymer, and the surfactant is an ethoxylated alkyl sulphate or , an alkyl glycoside or a salt thereof, a synthesis product of an alkenyl succinic anhydride and an alkyl glycoside, or a salt thereof, or a mixture thereof. 2. Sammansättning enligt patentkravet 1, nipple dnav, att det med hjälp av color eller syra pulp resin and ureaformaldehyde eller melaminformaldehydharts eller en blandning av dessa. Composition according to Claim 1, characterized in that the heat or acid curable resin is a urea-formaldehyde or melamine-formaldehyde resin or a mixture thereof. 3. Sammansättning enligt patent krav 1 eller 2, kanknetecknad därav, att resin and urea-formaldehyde resin, stem torrsubstanshalt and 30-60 vikt-%, fördelaktigt 35-50 vikt-%, och mol-förhällandet av formaldehyd och urea är 1,8 3.8: 1. Composition according to Claim 1 or 2, characterized in that the resin 15 is a urea-formaldehyde resin having a solids content of 30 to 60% by weight, preferably 35 to 50% by weight, and the molar ratio of formaldehyde to urea is 1.8 to 3, 8: 1. 4. Sammansättning enligt face av patentkraven 1-3, kanknetecknad därav, att samman-provisionningen omfattar 0,1-7 vikt-% av det ytaktiva ämnat ffän fibertorrmassan, närts ytaktiva rakne et ethoxylerat alkylsulfat, stem alkylkedand upp. 14 kolatomer, ·. ·. eller et Na-salt av detta eller en Na-alkylglycosid eller et Na-salt av denna, eller samman- • · • · provisionningenen omfattar 1-30 vikt-% av det ytaktiva ämnet räknat ffän fibertorrmassan, när • · «·. det ytaktiva ämnet är synthesproduct av en alkenylbenzenesenside anhydride och en alkyl- ··· .1.J 25 glycosid. • · • · · - - • · · · · · Composition according to one of Claims 1 to 3, characterized in that the composition comprises 0.1-7% by weight of the surfactant, based on the dry mass of the fiber, when the surfactant is an ethoxylated alkyl sulfate having from 12 to 14 carbon atoms in the alkyl chain. an atom, or its Na salt or alkylglycoside or its Na salt, or the composition comprises from 1 to about 30% by weight of surfactant based on the dry mass of the fiber when the surfactant is Synthesis product of alkenyl succinic anhydride and alkyl glycoside. The composition according to any one of claims 1 to 4, characterized in that the composition comprises a thermally or acid curable composition. 0.5-5% by weight of resin and 0-3% by weight of cationic acrylic • · ** 'amide copolymer based on the dry mass of the fiber. Composition according to any one of claims 1 to 5, characterized in that the cationic copolymer of acrylamide can be prepared from monomers comprising acrylic-1 amide, or from monomers in copolymeric cationic form such as quaternary acrylamide alkyl-n-alkylamine, secondary or tertiary acrylamide alkyl-n-alkylamine or primary acrylamine, acrylic acid ester having an alcoholic fraction of kvat -alkylamine alkoxide, or secondary or tertiary n-alkylamine alkoxide or primary amine alkoxide. 5. Sammansättning enligt face av patentkraven 1-4, kanknetecknad därav, att sammansättningen omfattar 0,5-5 vikt-% av det med hjälp av color eller syra pulp resin ·: **: och 0-3 vikt-% av den cationis sampolymeren av alaylamid räknat ffän fibertorrmas- *: 30 san. «· *** *** *** en ***: ***: 6. Sammansättning enligt nägot av patentkraven 1 - 5, kanknetecknad därav, att den cationic · namp sampolymeren av acrylamid kan ffamställas av monomerer, som omfattar acrylic- 16,107,951 amide, eller av monomer, sampolymer risk, cationic form, resin quaternary alkyl-n-alkylamin av acrylamides, secondary eller tertiary alkyl-n-alkylamin av acrylam eller, primary acrylamine, ester av acryls, and alcohols. n-alkylaminoalkoxide, eller secondary eller tertiary n-alkylaminoalkoxide eller primary amine alkoxide. 5 7. Sammansättning enligt face av patentkraven 1-6, kanknetecknad davav, att cationic-ten hos den cationic polymeric acrylamides 20-100%, fordelaktigt 25-80%, och molecular molecules 10,000-300,000, fordelaktigt 50,000-300,000. Composition according to one of Claims 1 to 6, characterized in that the cationic acrylamide copolymer has a cationic strength of 20-100%, preferably 25-80%, and has a molecular weight of 10,000-300,000, preferably 50,000-300,000. 8. Användning av en sammansättning enligt face av patentkraven 1-7 vid förfaranden for tillverkning av papper eller fibervävnad fungerande enligt skumbanformningsprincipen. Use of a composition according to any one of claims 1 to 7 in processes for making paper or nonwovens on a foam web basis. 9. A method for increasing the strength of a fibrous material, characterized in that the foam-impregnated paper or non-woven fabrication methods comprise adding to the fibrous slurry the composition or components of the composition according to any one of claims 1 to 7. · • i «i« i «i« i «i« i «i« i «i« i «i« i «i« i «i« i «i« i «« i «i« i «i« i «i«. · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · [Cap um. tecknat därav, att sammansättningen omfattar et med hjälp av colors eller syra härdande 5 resins eller blandningar av hartser, that actuate the och vatten samf valfit en cationic sampolymer av acrylamides, och det ytaktiva the etoxyle rat alkylsulfate eller et salt aven, en alkylglycosid eller et salt av denna, en syntheses av en alkenylbenzstensarcarbohydrides and alkylglycosid eller et salt av denna eller en blandning av ovannämn. 10 9. Förfarande för ekning av hällfastheten av ett fibermaterial, kännetecknat därav, att vid förfaranden för tillverkning av papper eller fibervävnad fungerande enligt skumbanform-15 ningsprincipen tillsätts i en fiberuppslamning en sammansättning enligt avting pat. •••••••••••••••••••••••••••••••••••••••••••••••••••• ·•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••