US 4,956,049 AGrant
Process for Sizing Paper With Anionic Hydrophobic Sizing Agents and Cationic Retention Aids
Issue Date:1990-09-11
•11 Claims
Abstract
Sizing agents, some of which are known compounds and some of which are novel aromatic compounds which contain in the aromatic nucleus a single hydrophobic substituent containing at least 5 carbon atoms and at least one anionic group, said hydrophobic substituent being linked to the aromatic nucleus through an ester, amide, urethane or urea bridge, with the CO group of ester and amide bridges being attached to the hydrophobic radical and a methylene group being optionally present between said bridges and the aromatic nucleus, are particularly suitable, together with commercially available retention aids, for use in a process for the mass sizing of paper or cardboard or for the surface sizing of paper.
Metadata
Assignee
- Ciba-Geigy Corporation
Inventors
- Michael Bernheim
- Dieter Strasilla
- Bernardo De Sousa
- Peter Rohringer
Application Information
Application Number:US 3722171
Filing Date:1989-06-23
Priority Date:1989-07-31
Art Unit:133
Classifications
IPC:
D21H 1714
Field of Search:
162158;179;164.3;164.6;166;168;175;181.1
Patent Drawings
This patent does not have any drawings.
Description
PREPARATION OF KNOWN COMPOUNDS AS SIZING AGENTS
Example A
A solution of 30.2 parts (0.1 mole) of stearyl chloride in 100 parts of toluene is added over 15 minutes to a suspension of 13.8 parts (0.1 mole) of salicylic acid in 200 parts of toluene. The reaction mixture is heated to reflux temperature of c. 111.degree. C. and kept for 10 hours at this temperature. Evolution of hydrogen chloride is observed during this time. The solvent is then removed by vacuum distillation, affording 38 parts of the compound of formula (11) in the form of a white powder which can be recrystallised from acetone for analysis. Melting point: 57.degree.-60.degree. C. Acid number: 142.
Example B
The procedure of Example A is repeated, using 13.8 parts (0.1 mole) of 4-hydroxybenzoic acid instead of 13.8 parts of salicylic acid, to give 36 parts of the compound of formula (12) as a white powder which can be recrystallised from chloroform for analysis. Melting point: 124.degree. C. Acid number: 135.
Example C To a suspension of 13.7 parts (0.1 mole) of anthranilic acid in 150 parts of toluene are added first a solution of 30.2 parts (0.1 mole) of stearyl chloride in 50 parts of toluene and then a solution of 20.2 parts (0.2 mole) of triethylamine in 80 parts of toluene, in the course of which addition the temperature of the reaction mixture rises to 45.degree. C. The reaction mixture is heated to reflux temperature of c. 111.degree. C. and kept at this temperature for 1 hour. The reaction mixture is cooled to 20.degree. C. and the product precipitates as salt, which is isolated by filtration and added to 60 parts of water. The pH of the resultant aqueous suspension is adjusted to 1.5 with a 30% aqueous solution of hydrochloric acid. The batch is then stirred for 4 hours, whereupon the product precipitates as free acid. The precipitate is isolated by filtration and vacuum dried, affording 36 parts of the compound of formula (16) in the form of a white powder which can be recrystallised from acetone for analysis. Melting point: 105.degree.-107.degree. C. Acid number: 141.
Example D
The procedure of Example C is repeated, using 13.7 parts (0.1 mole) of 3-aminobenzoic acid instead of 13.7 parts of anthranilic acid, to give 34 parts of the compound of formula (17) in the form of an ochre powder which can be recrystallised from dioxane for analysis. Melting point: 191.degree.-194.degree. C. Acid number: 141.
Example E
A solution of 10.9 parts (0.1 mole) of 4-aminophenol, 29.5 parts (0.1 mole) of octadecyl isocyanate and 0.2 part of 1,4-diazabicyclo[2,2,2]octane (catalyst) in 150 parts of toluene is heated to reflux temperature of about 111.degree. C. and kept at this temperature for 3 hours. The solvent is then removed by vacuum distillation, affording 38 parts of the compound of formula (31) in the form of a grey powder which can be recrystallised from dioxane for analysis. Melting point: 141.degree.-143.degree. C. Acid number: 135.
Example F 75.7 parts (0.25 mole) of stearyl chloride are added to a solution of 43.8 parts (0.25 mole) of aniline-3-sulfonic acid in 75.0 parts of water, 17.5 parts of an aqueous 25% ammonia solution and 91.0 parts of isopropanol. Simultaneously, 17.0 parts of an aqueous 25% ammonia solution are added from a separate vessel such that the pH of the reaction mixture remains between 5 and 6. The resultant white suspension is concentrated by evaporation and the residue is dried, affording 114 parts of the compound of formula (18) as a wax-like product. Melting point: 45.degree.-55.degree. C. (sintering temperature).
Example G
17.3 parts (0.10 mole) of aniline-3-sulfonic acid are dissolved at 60.degree. C in 100 parts of pyridine and 30.3 parts (0.10 mole) of stearyl chloride are added to this solution over 20 minutes, during which addition the temperature of the reaction mixture rises to 70.degree. C. The reaction mixture is further heated to 80.degree. C. and stirred at this temperature for 6 hours. To the resultant brown solution are added 110 parts of an aqueous 30% solution of hydrochloric acid. The reaction mixture is then further heated to 90.degree. C. and 400 parts of deionised water are added, whereupon a brown precipitate forms. The precipitate is isolated by filtration, washed with 100 parts of deionised water and vacuum dried at 50.degree. C., affording 43.7 parts of the compound of formula (19) as a wax-like product. Melting point: 40.degree.-50.degree. C. (sintering temperature). Acid number: 166.
Example H
The procedure of Example F is repeated, using 43.8 parts (0.25 mole) of aniline-4-sulfonic acid instead of 43.8 parts of aniline-3-sulfonic acid, to give 97 parts of the compound of formula (20) as a wax-like product. Melting point: 50.degree.-60.degree. C. (sintering temperature).
Example I, step 1
23.6 parts (0.25 mole) of aniline are dissolved at 40.degree. C. in 200 parts of pyridine. 75.5 parts (0.25 mole) of stearyl chloride are added over 30 minutes, whereupon the temperature of the reaction mixture rises to 55.degree. C. The reaction mixture is then heated to 100.degree. C. and kept at this temperature for 4 hours. With efficient stirring, this solution is then added to 4000 parts of deionised water, whereupon the product precipitates. The resultant light brown suspension is filtered and the filter product is washed with 1000 parts of water and vacuum dried at 40.degree. C., affording 88 parts of the compound of formula ##STR15## as a brownish floury powder. Melting point: 88.degree.-89.degree. C.
Example I, Step 2
36.0 parts (0.1 mole) of the stearanilide obtained as intermediate in step 1 are dissolved in 200 parts of chloroform and the solution is warmed to 30.degree. C. To this solution are added 6.65 parts (0.1 mole) of chlorosulfonic acid in an inert nitrogen atmosphere over 10 minutes, whereupon the temperature of the reaction mixture rises to 45.degree. C. and the hydrochloric acid generated by the reaction is removed from the reaction mixture. The reaction mixture is then stirred at 30.degree. C. for 1 hour, then heated to reflux temperature of c. 63.degree. C. and stirred at this temperature for 3 hours. The solvent is subsequently removed by vacuum distillation at 40.degree. C. and the residue is dried, affording 50 parts of the mixture of isomers of formula (21) as a light brown wax. Melting point: 50.degree.-60.degree. C. (sintering temperature). Acid number: 138.
Example J
54.6 parts (0.5 mole) of p-aminophenol are heated to 50.degree. C. in 200 parts of pyridine. To this solution are added 151 parts (0.5 mole) of stearyl chloride as a warm melt of 40.degree. C. The temperature of the reaction mixture rises to 65.degree. C. to form a suspension which is stirred for 4 hours at 50.degree. C. The reaction mixture is heated further to 90.degree. C. and, with efficient stiring, is added to 4000 parts of deionised water. The dark brown suspension is filtered and the filter product is washed with 300 parts of water and vacuum dried at 40.degree. C., affording 147 parts of the compound of formula (22) as a pale violet powder. Melting point: 120.degree.-122.degree. C. Acid number: 144.
PREPARATION OF NOVEL COMPOUNDS AS SIZING AGENTS
Example 1
The procedure of Example A is repeated, using 13.8 parts (0.1 mole) of 3-hydroxybenzoic acid instead of 13.8 parts of salicylic acid, to give 36.3 parts of the compound of formula (13) as a white powder which can be recrystallised from chloroform for analysis. Melting point: 87.degree.-91.degree. C. Acid number: 139.
Example 2
29.5 parts (0.1 mole) of octadecyl isocyanate are added at room temperature to a suspension of 13.7 parts (0.1 mole) of 3-aminobenzoic acid in 400 parts of toluene and the mixture is heated to reflux temperature of about 111.degree. C. The reaction mixture is kept for 1 hour at this temperature, then the solvent is removed by vacuum distillation and the residue is dried, affording 41 parts of the compound of formula (32) as an ochre powder which can be recrystallised from dioxane for analysis. Melting point: 266.degree. C. (with decomposition). Acid number: 132.
Example 3
29.5 parts (0.1 mole) of octadecyl isocyanate are added at 20.degree. C. over 10 minutes to a suspension of 13.8 parts (0.1 mole) of 3-hydroxybenzoic acid and 0.2 part of 1,4-diazabicyclo[2,2,2]octane (catalyst). The reaction mixture is heated to reflux temperature of c. 111.degree. C. and kept for 5 hours at this temperature, a clear solution forming after about 4 hours. The solvent is then removed by vacuum distillation, affording 40.8 parts of the compound of formula (26) as a white powder, which can be recrystallised from a mixture of acetone/hexane for analysis. Melting point: 112.degree.-122.degree. C. Acid number: 116.
Example 4
The procedure of Example 3 is repeated, using 13.8 parts (0.1 mole) of 4-hydroxybenzoic acid instead of 13.8 parts of 3-hydroxybenzoic acid to give 42.3 parts of the compound of formula (33) as a white powder which can be recrystallised from dioxane for analysis. Melting point: 177.degree.-183.degree. C. Acid number: 119.
Example 5
27.5 parts (0.25 mole) of resorcinol and 8.7 parts (0.11 mole) of pyridine are dissolved at 50.degree. C. in 100 parts of tetrahydrofuran. To this solution is added a solution of 30.3 parts (0.1 mole) of stearyl chloride in 50 parts of tetrahydrofuran at 50.degree. C. over 30 minutes. The reaction mixture is heated to reflux temperature of about 67.degree. C., stirred at this temperature for 4 hours, and then cooled to 25.degree. C. Then 250 parts of an aqueous 0.5N hydrochloric acid solution are added to the reaction mixture, whereupon the product precipitates. The precipitate is isolated by filtration, washed with 500 parts of water of 60.degree. C., and vacuum dried at 60.degree. C., affording 33.5 parts of the compound of formula (14) as a white powder. Melting point: 52.degree.-57.degree. C. Acid number: 147.
Example 6
58.6 parts (0.2 mole) of stearic acid and 22.0 parts (0.2 mole) of resorcinol are heated to 120.degree. C. To the resultant clear melt is added 0.2 part of 96% sulfuric acid and the mixture is heated to 160.degree. C. The water of reaction is expelled in a stream of nitrogen. The reaction mixture is stirred for altogether 2 hours at 160.degree. C. and then cooled to 20.degree. C., affording 74 parts of a crude product in the form of an orange powder which contains the compound of the formula (14) as indicated in Example 5. Melting point: 73.degree.-82.degree. C. Acid nummber: 143.
Example 7
The procedure of Example 5 is repeated, using 27.5 parts (0.25 mole) of pyrocatechol instead of 27.5 parts of resorcinol, to give 36.4 parts of the compound of formula (15) as a white powder. Melting point: 62.degree.-66.degree. C. Acid number: 152.
Example 8
22.0 parts (0.2 mole) of pyrocatechol and 1.1 parts of triethylamine are dissolved in 100 parts of tetrahydrofuran and the solution is heated to 60.degree. C. Then 59.1 parts (0.2 mole) of stearyl isocyanate are added to the above solution at this temperature over 20 minutes. The reaction mixture is then stirred for 6 hours at 60.degree. C. The solvent is removed by vacuum distillation at 40.degree. C. and the residue is dried, affording 79.0 parts of the compound of formula (27) as a dark brown powder. Melting point: 73.degree.-78.degree. C. Acid number: 142.
Example 9
The procedure of Example 8 is repeated, using 22.0 parts (0.2 mole) of resorcinol instead of 22.0 parts of pyrocatechol, to give 78.2 parts of the compound of formula (28) as a light brown powder. Melting point: 83.degree.-86.degree. C. Acid number: 140.
Example 10:
A solution of 32.8 parts (0.3 mole) of 2-aminophenol in 250 ml of tetrahydrofuran is added over 30 minutes at 50.degree. C. to a solution of 90.5 parts (0.3 mole) of octadecyl isocyanate in 200 parts of tetrahydrofuran. The reaction mixture is then stirred for 16 hours at 50.degree. C. to give a pale brown suspension. This suspension is cooled to 5.degree. C. and filtered. The filter product is vacuum dried at 40.degree. C., affording 30 parts of the compound of formula (34) as a beige powder, which can be recrystallised from ethanol for analysis. Melting point: 90.degree.-93.degree. C. Acid number: 139.
Example 11
The procedure of Example 10 is repeated, using 32.8 parts (0.3 mole) of 3-aminophenol instead of 32.8 parts of 2-aminophenol, to give 96 parts of the compound of formula (35) as a yellowish powder, which can be recrystallised from ethanol for analysis. Melting point: 108.degree.-111.degree. C. Acid number: 138.
Example 12
29.6 parts (0.1 mole) of stearyl isocyanate are added at 70.degree. C. over 20 minutes to a solution of 17.3 parts (0.1 mole) of aniline-2-sulfonic acid in 100 parts of pyridine. The clear solution so obtained is heated to 80.degree. C. and stirred for 5 hours at this temperature. After the addition of 110 parts of a 30% aqueous solution of hydrochloric acid, the reaction mixture is heated further to 100.degree. C. Then 400 parts of deionised water are added to the reaction mixture, and the resultant white suspension is cooled to 20.degree. C. and filtered. The filter product is washed with 300 parts of deionised water and vacuum dried at 40.degree. C., affording 35.2 parts of the compound of formula (36) as a pale grey powder. melting point: 71.degree.-73.degree. C. Acid number: 129.
Example 13
The procedure of Example 12 is repeated, using 17.3 parts (0.1 mole) of aniline-4-sulfonic acid instead of 17.3 parts of aniline-3-sulfonic acid, to give 43.5 parts of the compound of formula (37) as a pink wax-like product. Melting point: about 65.degree. C. (sintering temperature). Acid number: 122.
Example 14
17.5 parts (0.16 mole) of 4-aminophenol are dissolved at 0.degree. C. in 400 parts of 96% sulfuric acid and then 50.2 parts (0.16 mole) of N-hydroxymethyl stearamide are added, in portions, at this temperature over 4 hours. The reaction mixture is stirred for 48 hours at 20.degree. C. and then poured onto ice. The resultant suspension is filtered and the filter product is vacuum dried at 40.degree. C., affording 41 parts of the compound of formula (9) as a grey powder which is recrystallised from ethanol for analysis. Melting point: 150.degree.-160.degree. C. Acid number: 145.
Example 15
The procedure of Example 14 is repeated, using 22.6 parts (0.16 mole) of 4-nitrophenol instead of 17.5 parts of 4-aminophenol, to give 40 parts of the compound of formula (10) as a grey powder, which can be recrystallised from a mixture of ethanol/acetone for analysis. Melting point: 112.degree.-114.degree. C. Acid number: 136.
Example 16:
A solution of 44.0 parts (0.4 mole) of hydroquinone, 29.5 parts (0.1 mole) of octadecyl isocyanate and 0.12 part of 1,4-diazabicyclo[2,2,2]octane (catalyst) in 200 parts of toluene is heated to reflux temperature of about 111.degree. C. and stirred at this temperature for 6 hours. The reaction mixture is then cooled to 20.degree. C. and the product precipitates. The precipitate is isolated by filtration, washed with 300 parts of water of 60.degree. C. and vacuum dried, affording 35.5 parts of the compound of formula (29) as a white powder. Melting point: 84.degree.-87.degree. C. Acid number: 135.
Example 17
14.5 parts (0.14 mole) of triethylamine and then a solution of 41.4 parts (0.14 mole) of octadecyl isocyanate in 50 parts of toluene are added at 20.degree. C. to a solution of 17.7 parts (0.14 mole) of pyragallol in 100 parts of toluene and 150 parts of dimethylsulfoxide. The reaction mixture is warmed to 45.degree. C., stirred for 2 hours at this temperature and finally added to 500 parts of an aqueous 2N hydrochloric acid solution. The precipitated product is isolated by filtration, washed with water and vacuum dried, affording 37 parts of the compound of formula (30) as a slightly yellowish powder which can be recrystallised from ethanol for analysis. Melting point: 83.degree.-85.degree. C. Acid number: 261.
Example 18
A solution of 53.2 parts (0.18 mole) of octadecyl isocyanate in 50 ml of toluene and then 18.2 parts (0.18 mole) of triethylamine are added at 20.degree. C., over 20 minutes, to a suspension of 28.8 parts (0.18 mole) of 1,5-dihydroxynaphthalene in 200 parts of toluene. The reaction mixture is heated to reflux temperature of about 111.degree. C. and stirred for 16 hours at this temperature. The resultant clear reaction solution is then cooled to 20.degree. C. and the product precipitates. The precipitate is isolated by filtration, washed with an aqueous 1N hydrochloric acid solution and then with water, and finally vacuum dried, affording 63 parts of the compound of formula (38) as a pale brown powder which can be recrystallised from chlorobenzene for analysis. Melting point: 153.degree.-156.degree. C. Acid number: 122.
Example 19
To a suspension of 32 parts (0.2 mole) of 1,5-dihydroxynaphthalene in 200 parts of toluene are added, at room temperature, first 16.1 parts (0.2 mole) of pyridine, and then, over 40 minutes, a solution of 60.2 parts (0.2 mole) of oleyl chloride in 50 ml of toluene. The reaction mixture is heated to reflux temperature of about 111.degree. C. and then stirred at this temperature for 16hours. The solvent is subsequently removed by vacuum distillation. The distillation residue is dissolved in 250 parts of chloroform and washed with 100 parts of an aqueous 1N hydrochloric solution and then with 100 parts of water. The chloroform solution is dried over magnesium sulfate and evaporated to dryness under vacuum, affording 82 parts of the compound of formula (25) as a viscous product. Acid number: 129.
Example 20
The procedure of Example J is repeated, using 54.6 parts (0.5 mole) of o-aminophenol instead of 54.6 parts of p-aminophenol, to give 182 parts of the compound of formula (23) as a pale beige powder. Melting point: 75.degree.-77.degree. C. Acid number: 142.
Example 21
The procedure of Example J is repeated, using 54.6 parts (0.5 mole) of m-aminophenol instead of 54.6 parts of p-aminophenol, to give 178 parts of the compound of formula (24) as a pale beige powder. Melting point: 102.degree.-104.degree.. Acid number: 140.
Example 22
22.0 parts (0.2 mole) of pyrocatechol are fused at 110.degree. C. To this melt are added 60.5 parts (0.2 mole) of stearyl chloride over about 30 minutes such that the temperature does not exceed 120.degree. C. The vigorous evolution of hydrogen chloride is annulled by introducing an aqueous dilute solution of sodium hydroxide. The reaction mixture is heated further to 150.degree. C. and stirred at this temperature for about 30 minutes until the evolution of hydrogen chloride has ceased. The melt of the reaction mixture is poured into water. After filtration and comminution, 72.4 parts of the compound of formula (15) as indicated in Example 7 are obtained as a pale pink powder. Melting point: 62.degree.-68.degree. C. Acid number: 151.
APPLICATION EXAMPLES
Examples 23 to 48
To a fibre suspension which contains bleached birch sulfate pulp and pine sulfate pulp in a weight ratio of 1:1 in water of 10.degree. (German water hardness), and which has a Schopper-Riegler freeness of 35.degree. and a solids content of 0.5%, are added 20% of chalk as filler and then 0.01% of PERCOL.RTM. 292 (cationic high molecular weight (MG>1.10.sup.7) polyacrylamide) as auxiliary for retaining pulp fibre microparticles. The pH of the fibre suspension is as indicated in Table I below. The percentages refer to solids in filler and assistant, based on the solids content of the fibre suspension.
Formulations of the sizing agent are prepared by stirring 7% of each of the indicated sizing agents in powder form (obtained as crude product) with 3.5% of POLYMIN.RTM. P (polyethylenimine with a molecular weight of 10,000 to 100,000) as retention aid, in the presence of deionised water and of glass beads having a diameter 2 mm, at room temperature (15.degree. to 25.degree. C). The dispersions so obtained are pourable, homogeneous and storage stable. The percentages refer to solids in fillers and retention aids, based on the total weight of the formulation.
The aqueous formulation of the sizing agent and the retention aid is then added to the fibre suspension in such a manner as to give 0.5% solids content of sizing agent, based on the solids content of the fibre suspension. The fibre suspension is then processed in a laboratory "Formette Dynamique" sheet former (supplied by Allimand, Grenoble, France) to paper sheets which, after they have been dried at 130.degree. C. for 3 minutes, have a weight per unit area of 80 g/m.sup.2.
Both surfaces of the paper sheets so obtained, i.e. the surface obtained on the wire side of the sheet former and the adjacent or top side, are tested for their sizing properties. This is done by measuring the water absorption according to Cobb over 30 seconds (WA Cobb.sub.30)in accordance with DIN 53 132. The results of the WA Cobb.sub.30 measurements in g/m.sup.2 of the wire side (WS) and top side (TS) after drying at 130.degree. C. and storage for 1 day at 23.degree. C. and 50% relative humidity are reported in Table I. The lower the water absorption, the better the paper sizing. WA Cobb.sub.30 values above 100 denote a completely unsatisfactory sizing of the paper.
Similar results are obtained by replacing POLYMIN.RTM. P as cationic retention aid with CATO.RTM. 110 (cationically modified starch which is modified with a propylene oxide containing ammonium groups; pH of a 25% suspension in distilled water at 20.degree. C.=4.2 to 4.6), POSAMYL.RTM. E7 (cationically modified starch with a nitrogen content of 0.4%), HOFFMANN.RTM. B 118 (native potato starch cationically modified with trimethylglycidylasssonium chloride and having a nitrogen content of 1.3%), a condensate of dicyandiamide and triethylenetetramine which is further reacted with epichlorohydrin and is prepared in accordance with Example 2 of "German Offenlegungsschrift" No. 2,710,061, an adduct of epichlorohydrin and a reaction product of diethylenediamine and adipic acid, prepared in accordance with Example 1 of British Patent No. 865,727, a reaction product of dicyandiamide, formaldehyde, ammonium chloride and ethylenediamine, prepared in accordance with Example 1 of U.S. Pat. No. 3,491,064, or RETAMINOL.RTM. K (polyethylenimine of mol wt 20,000 to 40,000). Mixtures of the retention aids of the above indicated kind are also suitable. To obtain good results, it can be advantageous to add dispersants, in particular condensates of formaldehyde and naphthalenesulfonic acids, or carboxymethyl cellulose. However, only a poor sizing with Cobb values of about 150 to 200 are obtained by using a sizing agent of Example A, B, D, E, G, I, J or of any one of Examples 1 to 4, 7 to 11 or 13 to 22, but without retention aid, or a retention aid of the above indicated kind but without a sizing agent.
Examples 49 to 60
The procedures of Examples 23 to 48 are repeated, except that the sizing agent and retention aid are added separately to the fibre suspension. The sizing agent (6, 7, 10 or 15%) is stirred, in powder form, at room temperature (15.degree.-25.degree. C.), in the presence of water and glass beads, with an aqueous 5% ammonia solution to give a self-emulsifying, pourable and storage stable emulsion, which can be further diluted, of the sizing agent formulations as indicated in Table II. If desired, it is also possible to add direct salt-containing, self-emulsifiying, pourable and storage stable emulsions of the sizing agent as obtained in the synthesis, without the addition of ammonia. The val % indicates the number of equivalents of ammonia for 100 equivalents, based on the number of acidic groups contained in the respective sizing agent. The indicated amount of the retention aid POLYMIN.RTM. , expressed as solids, is added to the fibre suspension 10 seconds after the addition of the indicated amount of sizing agent, expressed as solids, said amounts being based on the solids content of the fibre suspension. The sizing results are also reported in Table II.
Sizing results analogous to those reported in Table II are obtained by using from 10 to 200 val % of ammonia or sodium hydroxide (as 5% aqueous solutions) for formulating the sizing agent.
Similar results are also obtained by first adding the retention aid to the fibre suspension and subsequently adding the sizing agent 10 seconds later. The same also applies by dispensing with the addition of PERCOL.RTM. 292 and/or of a filler. Similar results are likewise obtained by using talcum or kaolin as filler instead of chalk or by additionally using alum. Good sizing results are also obtained by using fibre suspensions which contain groundwood.
Example 61
A pure cellulose filter paper with a weight per unit area of 110 g/m.sup.2 is padded at a rate of 3 m/minute and a roller pressure of 20 kp/cm with an aqueous liquor which contains 18.4 g of an aqueous dispersion of 7% of the compound of Example 22 as sizing agent and 3.5% of POLYMIN.RTM. P as retention aid and which has been adjusted to pH 7.0 with an aqueous solution of acetic acid. The dispersion of the sizing agent and of the retention aid is prepared as described in Examples 23 to 48.
The pick-up is 78% (0.1% of pure sizing agent, based on the paper to be treated). The padded paper is dried between two sheets of filter paper for 3 minutes at 90.degree. C. The dried, treated paper has a WA Cobb.sub.30 value of 19 /m.sup.2. After storage for 1 day, the WA Cobb.sub.30 value of the treated paper is 16 g/m.sup.2. Similar results are also obtained by using dispersions or melt emulsions which contain, as sizing agent, a compound of any one of Examples H to J or of any one of Examples 1 to 21 instead of the compound of Example 22.
Claims
What is claimed is:
1. A process for sizing paper or cardboard which comprises treating the fibers thereof with (A) a sizing agent of the formula ##STR16## wherein A.sub.1 and A.sub.2 are each an anionic carboxyl, hydroxyl or sulfo group which is acidic or in salt form, D.sub.1 is phenylene, naphthylene, dihydronaphthylene or tetrahydronaphthylene, each of which is unsubstituted or substituted by halogen, nitro, amino or hydroxyl, R.sub.1 is alkyl or alkenyl, each of 5 to 22 carbon atoms, X.sub.1 is a bridge of the formula --O--CO--, wherein the terminal --CO-- group of said bridge is attached to the alkyl or alkenyl radical R.sub.1, and m and n are each 1 or 2, and (B) a polyethyleneimine retention aid.
2. A process according to claim 1 for mass sizing paper or cardboard, which comprises adding components (A) and (B), in either order or simultaneously, to an aqueous cellulose-containing fiber suspension which optionally contains filler.
3. A process according to claim 1 for surface sizing paper, which comprises impregnating said paper with an aqueous sizing liquor which contains components (A) and (B) drying said paper.
4. A process according to claim 1, wherein the retention aid (B) has a molecular weight of 1000 to 2,000,000.
5. A process according to claim 2, which comprises using 0.02 to 3 percent by weight of the sizing agent (A) and 0.02 to 3 percent by weight of the retention aid (B), both amounts being expressed as solids in (A) and (B) and based on the solids content of the fibre suspension.
6. A process according to claim 2, which comprises using, as optional filler, a condensate of formaldehyde and urea, titanium dioxide, talcum, kaolin, montmorillonite or chalk.
7. A process according to claim 2, wherein the fiber suspension has a Schopper-Riegler freeness of 10.degree. to 60.degree. and a solids content of 0.1 to 5 percent by weight.
8. A process according to claim 2, wherein the fiber suspension contains sulfite and/or sulfate pulp obtained from coniferous and/or hardwood, optionally groundwood and/or alum containing waste paper.
9. A process according to claim 3, wherein the paper is dried in the temperature range from 60.degree. to 140.degree. C.
10. A process according to claim 1, wherein D.sub.1 is phenylene or naphthylene, each unsubstituted or substituted by chlorine, bromine, nitro, amino or hydroxyl, m is 1 and n is 1 or 2, X.sub.1 is --O--CO-- and R.sub.1 is alkyl or alkenyl, each of 5 to 21 carbon atoms.
11. A process according to claim 1, which comprises using, as component (A), a sizing agent of the formula ##STR17## ##STR18## wherein R.sub.4 is alkyl or alkenyl, each of 15 to 21 carbon atoms, and X.sub.2 is --O--.
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