IL46283A - Cationic polyurethanes their production and paper sizing agents containing them - Google Patents

Abstract

Cationic polyurethanes are prepared by reacting a monomeric, aliphatic dihydroxyl compound containing a maximum of 7 atoms between the two hydroxyl groups and containing an aliphatic radical having at least 10 carbon atoms on one of said atoms with a polyisocyanate to give a preadduct containing NCO end groups, chain-extending the resultant preadduct by means of an aliphatic monomeric diol containing tertiary nitrogen, and converting the chain-extended product into an ammonium compound. These polyurethanes are particularly suitable as the active component in paper sizes. The sizes can be employed both in bulk sizing and in the surface sizing of paper and give sized papers having a high degree of sizing and a low Cobb value. Sizing in a relatively broad pH range is possible, and the polyurethanes can be processed very well together with products usually used for sizing. [GB1491091A]

Description

* »¾?ani Dili" f e>»ai»»p o»smvK*¾>iD Oetloalo polyurethanes* their productloii and paper sizing agents containing them The present invention relates to cationic polyurethanes, to a production and to their use as sizing Cationic polyurethanes have long been known.

Cationic polyurethanes are polyurethanes containing one or more atoms with a positive charge in the polymeric molecule. Compounds of this kind can be obtained for example from polyurethanes containing groups capable of onium formation.

The production of polyurethanes of this kind is described for example, in German Patent Specification No. 880^-85. The compounds mentioned in that Patent Specification are prepared as follows. The starting compound used is, for example, a glycol containing a group capable of onium formation, such as tertiary nitrogen or ether oxygen. This glycol is reacted with an equivalent quantity of a diisocyanate and the products obtained in this way treated with polyfunctional and, optionally, even wixu mo oiuiiei o a alkylating gen s.

It. is also known that a prepolymer containing NC0-groups can initially be prepared from polyesters (German Patent No. 891,7^2) containing terminal hydroxyl groups, and subsequently further reacted with dihydroxy compounds containing groups capable of onium formation.

Other cationic polyurethanes are described, for example, in German Offenlegungsschrift No. 1,595*602 and in the article by , Dieterich e al in "Angewandte Chemie vol 82 (1970), No. 2, pages 5 to 63» It is known that compounds of this kind can. be used as textile auxiliaries, dyeing auxiliaries, for producing' th ckene a, rubber-l ke , or even glass- suitable for coating and for impregnating woven and nonvoven textiles/ leather, paper, wood, metals, ceramics, stone, concrete, bitumen, hard fibres, glass, porcelain, various kinds of plastics, for antistatic and noncrease finishing, as binders for nonwovens, adhesives, adhesion promoters, laminating agents, hydrophobising agents, plasticisers, binders, for example for powdered corlc or sawdust, glass fibers, asbestos, paper-like materials, plastics or rubber waste, ceramic materials, as auxiliaries in cloth printing and in the paper industry, as additives to polymer dispersions, as sizes and for finishing leather and also as sizing agents for paper.

Non-cellular polyurethane compositions which cure rapidly on exposure to atmosphere at ordinary ^ temperature and form hard coatings having outstanding adhesion, toughness, flexibility, resistance to abrasion and discoloration are known from U.S. Patent Specification 2,966,472. Such compositions are particularly suitable for use as protective coatings on metals and wood.

Such compositions are obtained by reacting a monobasic fatty acid triglyceride with a polyisocyanate of the aromatic series, and thereafter reacting the monobasic fatty acid triglyceride-polyisocyanate thus obtained, with a hydroxy-aIky1amine in a suitable solvent.

Although a large number of cationic polyurethanes have already been described in the literature, there is etill a demand for compounds of this kind because, on the one hand, the processes by which they- arc conventionally produced involves certain difficulties and because, on the other hand, the properties of conventional cationic polyurethanes arc unsatisfactory and in need of improvement for certain application.

It has now surprisingly been found that cationic polyurethanes with outstanding properties can be obtained by reacting a monome c aliphatic dihydroxy compound, containing an aliphatic substituent with at least 10 carbon atoms, with a polyisocyanate to form a prcadduct containing terminal NCO-groups and chain-extending the prcadduct thus obtained either with an aliphatic monomeric diol containing tertiary nitrogen followed by conversion of the chain-extended product into an ammonium compound, or with, a corresponding monomeric aliphatic diol ; ammonium compound. In the context of the invention, ammonium compounds are compounds containing positively charged nitrogen, as is the case for example with salts of tertiary amines or with quaternary ammonium salts.

Monomeric aliphatic dihydroxy compounds containing an aliphatic .substitucnt with at least 16 carbon atoms are particularly suitable. In the. context of the invention, monomeric aliphatic dihydroxy compounds ' are non-polymeric aliphatic glycols^ i.e. organic conrpounds with two hydroxyl groups in the 1,2- or 1,3-position or in any other position, for example the a,L/-position. It is preferred to use monomeric substituted aliphatic dihydroxy compounds wherein the two hydroxy groups are attached to one another by at most 7 atoms in the aliphatic chain.

The aliphatic siibstituent, which the aliphatic dihydroxy compound must contain, ma.y ;be situated on a carbon atom attached to one of the two hydroxy groups, although it may also be situated on a carbon atom lying between those carbon atoms attached to the two hydroxy functions. Preferably, the aliphatic substituent contains from 10 to 22 carbon atoms 0 In addition, it is not absolutely essential for the aliphatic chain of the ,glycol, through which the two hydroxy groups are attached to one another, to contain only carbon atoms. Thus, one carbon atom may be replaced by a hetcro atom such as oxygen or nitrogen. If the hetero atom present in the aliphatic chain is nitrogen, the aliphatic substituent may contain at least 10 carbon atoms, preferably at least 16 carbon atoms and may in fact be attached to the hetero atom. If a hetero atom is situated in the aliphatic^*', chain, it is essential for the purposes of the process according to the invention that no radical capable of reacting with isocyanate groups should be present on the hetero atom during the reaction of the dihydroxy compound with the polyisocyanates . Thus when, for example, nitrogen is present in the chain, the third valence must be satisfied by a radical without any active hydrogen atoms.

The aliphatic substituent on the dihydroxy compound must contain at least 10 carbon atoms and preferably at least 16 carbon atoms. It is not absolutely essential for the substituent to be merely a corresponding hydrocarbon radical. Aliphatic substituents in the context of the invention also include the group RC00-, where It is an alipjiatic radical -with at least 9 carbon atoms and preferably with at least 15 carbon atoms. Glycerin fatty acid monoesters, for example glycerin monostcarate or glycerin behcnic acid onoester, are particularly suitable.

N-Substituted dialkanolamines, especially N-stearyl d ethanolamine, arc mentioned as examples of coiiipotmds in .which one carbon atom in the aliphatic chain is replaced by a hetero atom. 1, 2-Dihydroxy octadecane and 1 , i-dihydroxy octadecane have also proved to be very suitable dihydroxy compounds containing a substituent with the corresponding number of carbon atoms for the purposes of the invention.

The reaction of the substituted monomeric aliphatic dihydroxy compound with a polyisocyanate is best carried However, the reaction may also be carried out in other solvents which are inert with respect to isocyanate groups 01- which show only limited rcactivityNby comparison with< ■ the reaction components. Solvents of 1this kind are tetrahydrofuran, dimethyl forraamide , chloroform, per- chlorethylene, methylene chloride, methyl ethyl ketone, ethyl acetate, dimethyl sulphoxide.

However, reaction of the aliphatic substituted dihydroxy compound with the polyisocyanate may also be carried out in the melt, i.e. in the absence of a solvent.

Catalysts may be used, for the reaction of the dihydroxy compound with the polyisocyanate. Diacetoxy dibutyl tin has proved to be a particularly suitable catalyst, although it is also possible to use other catalysts such as dibutyl tin laurate, cobalt naphthenate, zinc octoate and tertiary amines, for example tri ethyl amine or 1,4-diaza-[2, 2, 2]-bicyclooctane. The diols containing tertiary nitrogen used for chain extension may also be used as catalysts. -j The polyisocyanates used for preparing the preadduct may be both aliphatic and aromatic polyisocyanates.

Mixed aliphatic/aromatic compounds may also be used. It is preferred to use diisocyanates^, Tolylene diisocyanate, dipheiryl ethane-;x, ' -diisocyanate and hexamethylene diisocyanate have proved to be particularly suitable.

It is also possible to use so-called masked diisocyanates such as, for example, the reaction product of diphenyl methane--2.-, 4'-disocyanate with 2 mols of phenol0 Among the triisocyanates which may be used in the present invention., the addition product of glycerin and 3 mols of tolylene diisocyanate and also trj.-(;i-isoc anato-phenyl )-monothiophospbate, have proved to he particularly uncontrollable crosslinking can occur' very easily in cases where only, or alternatively a large proportion of, polj^isocyanates with three or more isocyanate functions in the molecule are used, and in fact generally, it is preferred to use aromatic diisocyanates in the practice of the invention.

The ratio between the reactants, i.e. the molar ratio of dihydroxy compound to polyisocyanate, may be varied within a relatively wide range. Thus, it is possible for example to use a molar ratio of dihydroxy compound to diisocyanate in the range from 1:1.1 to 1:3. The molar range from 1:1.5 to 1:2.5 is particularly suitable, a ratio of exactly 1:2 being preferred.

The proadciuot obtained av then bo reacted with substantially equivalent quantities of an aliphatic diol containing tertiary nitrogen. In the context of the invention, equivalent quantities mean that it is possible to use the same number of hydroxyl groups of the diol relative to the number of isocyanate groups present, N-Methyl diethanolamine and 1,2-propane diol-3-dimethyl amine have proved to be particularly suitable aliphatic diols containing tertiary nitrogen. It is of course also possible to use other compounds containing tertiary nitrogen, such as for example N-n-butyl diethanolamine, N-t_-butyl diethanolo.minc, N-methyl dipropanolamine, N- -bis- 2-hydroxy etbyl-p_-toIidine and 1, 4-bis-hydroxy ethyl piperazine. The dio preferably contains only one or two tertiary nitrogen atoms and gejnerally has a molecular weig t of less than 300, preferably less than 200. The reaction of the preadduct with the diol is generally a chain- extending reaction.

The reaction of the preadduct with the chain extender is preferably carried out in an anhydrous, solvent, acetone having proved to be particularly suitable, and is best carried out at boiling temperature. The course of the reaction may be followed by an appropriate socyanate determination method. Towards the end of the reaction the NCO content should be less than I f , The chain-extended product is then converted into an anunonium compound. The pair of electrons still free in the tertiary nitrogen are bonded, so that the nitrogen receives a positive charge. In this operation, hydrogen from a suitable acid or an allcyl group may be bonded to the tertiary nitrogen. This operation, which follows chain extension, may be circumvented by using, for chain extension a corresponding glycol which is already present in the form of an ammonium compound, for example a salt which has been obtained by reacting an acid with a glycol having tertiary nitrogen, for example the hydrochloride of N-methyl dietbano1amine .

Conversion of the chain-extended product obtained into an ammonium compound is preferably carried out with hydrogen chloride. It may be carried out with aqueous IICl, although HCl .gas may also be introduced into a solution. Λ solution of HCl in acetone may also be used wit good effect. Conversion into an ammonium compound may also be carried out with a conventional alkylating agent. It is preferred to use dimethyl sulphate. ( , Extremely favourable results arei obtained b replacing with hydrogen chloride. It is possible in this way to bond the methyl group, rather than hydrogen, to some of the tertiary nitrogen atoms.

For conversion into an ammonium compound, it is of particular advantage to use acid or alkylating agent in only such a quantity that from 5 to 200 milliequivalents per 100 g of polymer of the tertiary nitrogen atoms are converted into the ammonium form. The quantity of acid or alkylating agent required for adjusting a value in this range may readily be calculated from the quantities of starting materials used.

It is particularly favourable to convert the chain-extended product -into an ammonium compound before drying. In the context of the invention, by intermediate drying is meant a suitable method of treatment. by which the solvents used, if any, or residues of other liquids may be removed. Spray drying or treatment in a rotary evaporator are Ijarticularly suitable for this, purpose.

The product which has been subjected to intermediate drying may then be suspended, for example in water, and converted into an ammonium compound by the addition of hydrochloric acid. In cases where acids, such as hydrochloric acid, are used, it is best not to add the chain-extended product to them,, bu instead to add the acid slowly to the chain-extended product.

The invention also relates to cationic polyurethanes obtainable by reacting a monomeric aliphatic dihydroxy compound, containing an aliphatic substituent with at , least 10 carbon atoms and preferably with 16 carbon atoms, with a polyisocyanate to terminal NCO-groups, and chain-extendf-fig the preadduct with an aliphatic diol containing tertiary nitrogen, and converting the chain-extended product into an ammonium compound by treatment with an acid or an allcylatlng agent.

The polyurethanes according to the invention may be obtained from the starting compounds referred to previously in the description of the process according to the invention.

The cationic polyurethanes according to the invention may be built up from structural units corresponding to the general formula ABAD, the members by which the structure is built up having the following meaning: 0 0 II II A = -C-NH-R-NII-C-. where R = a divalent aliphatic, aromatic or araliphatic radical CHo0R« B a -0Cn2-CH0R?-CH 0- or -O-CH-CHg-O- where 0 II R' = -C-R" R" = CnH-in + ,x n = 9 to 21 © D CHg) -- 0 - - X~ or where R'" - Cn ,1JT2rjn ,' .J+ ·!Ί, —η' = 1 to 4, and r = 2 to 6, s = 2 to 6 and x~ is an acid radical, preferably Cl~.

Member B may also be of the following types — OCII— CHyO — where m = 10 to 22 preferably 16 to 22 or —0—CH — CH2— CII2 dig 0 — Cm'H2m> + 1 where m' = 10 to 22 preferably 16 to 22 or — 0 — CH2 CII2 N CH2 CH2 0 — CmH2m+l where in = 10 to 22 preferably 36 to 22 Member Λ is formally derived from a diisocya.nate and is explained by the formula which reproduces the structure as it exists within the polymer chain. It is obvious to the expert that member A, where it is terminal, contains a terminal isocyanate function, i.e. the -N=C=0- group. The same applies as regards member D which is formally derived from a diol and which, once again, is also shown in the formulae as a member within the polymer chain which, where it is terminal, contains a terminal hydrox 1 group. The. terminal groups may also be modified by secondary reactions.

The process according to the inventio gives cationic polyurethanes with outstanding properties in a very simple advantageous manner. The reactions are substantially quant tative. No s ther do any undesirable eross n ng reac ons a e p ace.

The solvent used, if any, is very easy to recover. The individual reactions take place quickly, with the result that a high conversion may be obtained in the process according to the invention. The successive reactions leading to the cationic po-lyurethane may be carried out one after the other in different vessels. However, the individual reactions may also be carried out in a single \ressel. It is also possible to simultaneously react the starting compounds required, for forming the cationic polyurethane according to the invention. In particular, the chain-extended product may be prepared by a so-called one-pot process. However, the preadduct is preferably formed to begin with, followed by chalin extension.

The properties of the cationic polyurethanes may be varied within a wide range by selecting suitable starting compounds. Thus, the use of aromatic diisocyanates generally leads to cationic polj'urethanes with even better properties. The particle size of the polyurethanes may be influenced by varying the proportion of nitrogen atoms converted into the ammonium form, and it is possible to obtain coarse-particle, fine-particle and even colloidal systems. · The basicity of the polyurethanes according to the invention is generally higher when chain extenders in whicl .1.2 e er ary n rogen, or ammon um n rogen s no rec y situated in the chain between the two hydrox 1 groups, are used. 1,2-Propane diol-3-dimethyl amine is one example of such a compound.

The cationic polyurethahes obtained arp extremely stable in storage. They may be processed in the form of solutions or dispersions. They may readily be admixed with other additives, and may be processed into shaped articles, for example films. They are also suitable for coating various kinds of plastics.

It is particularly surprising that the cationic polyurethanes produced in accordance with the invention should represent very valuable sizing agents for paper.

The invention further relates to a sizing agent for paper containing the cationic polyurethanes according to the invention. The sizing agents according to the invention may be used for sizing paper by methods known per se.

Thus, the polyurethanes have proved to be effective sizing agents both for the bulk sizing and also for the surface sizing of paper. It is also possible to carry out both processes at the same time with the sizing agents according to the invention. It is also possible to carry out bulk sizing with conventional sizing agents, for example resin sizes, followed by surface sizing with the ί cationic polyurethanes according to the invention.

More details on the sizing of paper may be found, fox" example, in the book by Engelhard, Granich and Hitter entitled "DAS Leimen von Papier" VEB, Fachbuch-Verlag Leipzig, 1972.· By using the cationic polyurethanes according to the invention, sizing may be carried out at pl-l-values within a relatively wide range, so that chalk may. also be used as filler. The compatibility of the polyurethanes with aluiii is excellent. They may be processed very effectively degraded either by oxidation or by fermentation or chemically modified, cellulose derivatives , for example carboxy methyl cellulose, cellulose ethers, polyvinyl alcohol and alginates. · In cases where the catioiiic polyurethanes produced in accordance with the invention are used for sizing paper, ' the sized paper exhibits extremely favourable sliding friction so that no difficulties which can be atrributed to a decrease in sliding friction are encountered during processing, for example during stacking of the paper. In addition, papers which have been sized with the sizing agent acc rding to the invention show outstanding processing properties when it comes to rolling and cutting, and so on.

A very good degree of liming is obtainable with the cationic polyurethanes. One particular advantage is that the sizing effect is instantaneous and, once applied, the size remains effective over pi~olonged storage periods.

This is . of considerable importance, above all in the case of raw pape for coating, because uniform ink uptake is required during further processing.

Hardly any effluent -problems occur either in the production of the polyurethanes or where they are vised, for sizing paper. It is particularly emphasised that, where the polyuretlianes are used as sizing agents, foaming is largely avoided both in hulk sizing and also in surface sizing.

The favourable sizing properties of the product are also emphasised insofar as they enable/sizing to be carried out with far less material than is the case with conventional products. The starting compounds are readily obtainable, so that no difficulties are involved in large-scale production...

The cationic polyuretlianes according to the invention may be used for full sizing, three quarter sizing, half sizing and quarter sizing.

The invention is illustrated by the following Examples. The test methods referred, to in the Examples are described below: 1. Degree of sizing against ink with the Hercules Sizing Tester, in accordance with the operating instructions of the manufacfrurers , Hercules Incorporated, Wilmington Delaware, USA. The quantity measured is the time in seconds elapsing until an 80 $ decrease in the remission value of paper is obtained when the test ink is applied to the paper and breaks through the paper.

Test ink: Papier-Pruftinte , Dlau, as defined in DIN 53126 . Cobb Test: (DIN standard 53/32 - 1 minute) a) Absorbency with respect to water, expressed in of water taken up after 1 minute's contact with water. b) Absorbency with respect, to .10 Naf,C07 solution, . . . * 1) expressed " n g m a er m nu e s con ac , as in 2a).

Further particulars of the test methods may he found in the hook by Engelhardt e_t al referred to previously.

EXAMPLE 1 The apparatus used is a heatahle, 500 ml capacity th ee-necked spherical flask equipped with a stirrer, reflux condenser with drying tube and a dropping funnel. 1 .5 g of standard conmiercial-grade glycerin mono- stearate (0.0545 mol) are introduced into the flask. 15 mg of dibutyl tin diacetate, 24 ml of anhydrous acetone and 16.0 ml (19.5 g) of an 80 : 20 mixture of 2,4- and 2,6- tolylene diisocyanate (0.112 mol), are then successively added.

The reaction vessel is then heated for 30 minutes with stirring until the solvent begins to reflux gently.

In the meantime the reaction temperature is approximately ' 65°C A solution of 6.5 g of N-rmethyl diethanolamine (O..05 6 mol) in 20 ml of anhydrous acetone is added dropwise over a period of 10 minutes, followed by heating in such a way that a moderate reflux is again maintained.

After a reaction time of 60 minutes, the NCO-content has fallen to beloitf 1.5 , and a moderately viscous, crystal-clear solution of the polyurethaue has formed, being diluted by the addition of 160 ml of commercial-grade acetone.

For salt formation, 27.3 ml of 2 hydrochloric acid ai"e added over a period of approximately 5 minutes. There- a er e sa s presen par y n co o a orm an partly in the form of a white precipitate whic is dissolved by running in 140 ml of water over a period of 15 minutes during which the contents of the temperature of approximately 50°C.

The clear solution formed is freed from the acetone by vacuum distillation. Λ 20 $ by weight, slightly opalescent, pale yellow coloured solution of the polyurethane ionomer is obtained.

The concentration can be increased by distilling off more water. At 32 by weight the polymer solution is still free-flowing, EXAMPLE 2 The procedure is as in Example 1, except that 6.5 g instead of 6.0 g of N-methyl diethanolauiine are used, and salt formation is carried out with 25.2 mol of 2-normal hydrochloric acid. The polyurethane solution is not further diluted with acetone before addition of the hydrochloric acid.

' A shimmering blue emulsion with an average particle size of 0.5 to 1 urn is formed.

EXAMPLE 3 The procedure is as in Example 2, except that the chain-extended product is subjected to intermediate dicing by spray drying. The product thus dried has a melting point of approximately 93°C.

For conversion into an ammonium compound, the dried product is suspended in water, followed by the gradual . reaction betwee glycerin monostearate^and tolylene diiosycanate is catalysed by 3 $ of the total quantity of N-methyl diethanolaniine which is deducted for chain extension. A product of the same kind as in Example 1 is formed. - EXAMPLE 5 ' The procedure is as in Example 1, except that the solution of the N-methyl diethanolaniine in acetone is added dropwise immediately after dissolution of the glycerin monostearate and tolylene diisocyanate, i.e. without a preliminary reaction of these components catalysed by the addition of organo tin compounds, tertiary amines or • ! compounds with a -similar effect. The reaction time is 2 hour's. The dispersion of the ionomer is slightly clouded.

EXAMPLE 6 9.5 g of ^lyoerin monostearate are initially iiltroduced and heated to melting point. 16 ml of tolylene diisocyanate are then added dropwise in such a way that the temperature does not exceed 75°C. On completion of the exothermic reaction, the reaction mixture is stirred for another 20 minutes at 75°C The melt is then dissolved by the addition of 50 ml of anhydrous acetone.

Further reaction with N-methyl diethanolaniine, salt formation and dispersion is as in Example 1.

EXAMPLE 7 The procedure is as n_xauiple 1, except that 8.0 g of N-butyl diethanolamine are used instead of 6.5 g of ■ W N-jnethyl diethanolamine. Λ fine-particle opalescent dispersion is formed.

EXAMPLE 8 The procedure is as in Example 1, except that 29.4 g of bis-(½—isocyariatocyclohexyl )~methane are used instead of I9.5 g of tolylene diisocyanate. A slightly opalescent solution is obtained.

EXAMPLE 9 The procedure is as in Example 1, except that only 80 of the tertiary nitrogen is neutralised by reducing the quantity of hydrochloric acid to 21.9 ml.

A stable, fine-particle emulsion is formed.

EXAMPLE 10 The procedure is as in Example 1, except that the glycerin monostearate ic replaced by 19.5 g of N,N-di~c-hydroxyethyl stearylamine .

EXAMPLE 11 , The procedure i; as in 'Exam le 1, except that the glycerin monostearate is replaced by 15.6 g of 1,2-dihydroxy octadecane.

A slightly opalescent, pale yellow dispersion is obtained. to and including . 25 $ of the -tertiary nitrogen is quaternised hy the addition of 0.86 g of dimethyl sulphate, followed hy reaction under reflux for another 30 minutes.

After dilution with l60 ml of commercial-grade acetone, 20.4 ml of 2N-hydrochloric acid are added dropwise, followed hy dispersion as in Example 1.

A stable, fine-particle emulsion with strongly cationic centres is obtained as the end' product.

EXAMPLE 13 A cellulose pulp for producing paper is bulk-sized in a Hollander in known manner. Of the total pulp input, 70 $ consists of bleached pinewood pulp and 30 $ of bleached beechwood pulp. In addition, 1 $ of sizing agent produced in accordance with Example 2 is added. Bulk sizing is carried out once without the addition of a retention agent and then in the presence of 0.3 of a standard commercial-grade retention agent (polyami.de amine).

The papers produced have a weight per unit area of 70 g/m . For comparison, bulk sizing was carried out with a standard commercial-grade cationic size based on modified I inaleic acid anhydride-s tyrene copolymers under otherwise the same conditions.

The degree of sizing, the Cobb water value and the Cobb value of 10 $ soda solution were measured on the papers produced in this way. The results are set out in the following Table.

• Table 1 Polyurethane produced Standard in accordance w commercial- Exanip1 e 2 grade ,produ degree of sizing (seconds) without retention agent 458 140 with 0. 3 of retention agent . 833 190 Cobb (water) without retention agent 27 28 with 0. 3 % of retention agent 27 Cobb ( 10 soda solution) without retention -agent 20 22 Atfith 0. 3 of retention agent 19 20 EXAMPLE 14 An unsized raw paper weighing 80 is treated i a sizing press with a size containing 10 of potato starch degraded by oxidation and 0. 25 of a.d. sizing agent produced in accordance with Example 2. The paper takes up 1. 85 1° of dry substance, based on its own weight, in the sizing press. . · Surface sizing is carried out using a standard commercial-grade cationic sizing agent based on modified maleic acid anliydride-styrene copolymers under otherwise the same conditions. The values measured on the paper f are set out in Table 2 .

Table 2 Standard . Polyu ethane commercial- dispersion grade product O—Eilxxaaimp 1 e Degree of sizing (Hercules seconds) 310 1590 Cobb value (water) 1 minute 26 19 EXAMPLE 15 Surface sizing is carried out under the same conditions as in Example I k , .except that the. size contains only 5 $ of starch and 0. 3 $ of a.d. sizing agent. The paper takes up 1 . 8 of dry tfcsasbstance in the sizing press. The properties measured on the paper are set out in Table 3.

Table 3 Commercial Polyu ethane product dispersion accor to Example 2 Degree of sizing (seconds) 120 . 9 0 Cobb value (water) 1 minute 37 1,9 Cobb value ( 10 J¾ soda solution) 27 15 1 minute EXAMPLE 16 Surface sizing is carried out under the same conditions as in Example 15 , except that 0. 2 and 0. 3 of a.d. sizing agent according to Example 1 are used. The properties measured on the paper are set out in Table . 0.2 of a.d. 0.2 ^ of a.d. standard . polyure hane . commercial dispersion ac' product ;'o Examp1e 1.

Degree of sizing (sees) 218 2136 Cobb value (water) 1 minute 47 21 Cobb value (10 soda soluti 1 minute 40 !7 0.3 of a.d. 0.3 of a.d. standard polyu ethane commercial- dispersion accordi grade product to Example 1 Degree of sizing (sees) 312 2602 Cobb value (water) 1 minute 33 19 Cobb value (10 f> soda solution) 1 minute 30 16 EXAMPLE 17 Λ cellulose pulp for producing paper is bulk-limed in a " i Hollander in known manner. Of the tbtal pulp input, 75 consists of bleached pinewood sulphite cellulose, 1 of bleached birchwood sulphate pulp and 10 > of bleached Scotch pine sulphate pulp ground to a fineness of 40° SR.

In addition, 1 of a.d. sizing agent produced in accordance with Example 1 is added. 2 The papers produced in this way weight 45 g/iu · The test results are set out in Table 5.

Col.il) value (water 1 minute Cobb value (10 soda solution) 1 minute 13 EXAMPLE 18 An unsized raw paper weighing 80 g/m is treated in a. sizing press with a size containing only 0.50 $ of a.d. sizing agent produced in accordance with Example 1.

The properties measured on. the paper are set out in Table 6.

Table 6 0.5 of a.d. 0.5 of a.d. standard polyurethane commercial grade dispersion accord product to Example 1 Cobb value (water) 1 minute 21 15 Cobb value (10 j(o soda solution) 1 minute 21 16 EXAMPLE 19 An unsized raw paper weighting 80 g/m 2 is treated in a sizing press with a size containing 5 of starch and 0.3 # of a.d. sizing agent produced in. accordance with Example 11.

The properties measured on the paper are set out in Table 7.

Table 7 standard Polyu ethane commercial grade dispersion accord product to Example 11 Degree of sizin (seconds) 300 1250 Cobb value (water) 2k 17 Surface sizing is carried out under the same conditions as in Example 15 , except that 0. 1 , 0. 2 and 0. 3 # of a.d. sizing agent according to Example 12 are used.

The properties measured on the paper are set out in Table 8.

Tab e 8 0. 1 of a.d, 0. 1 of a.d. standard polyuretha e commercial grade dispersion , product according to .

Example 12 Degree of sizing (seconds) 55 Cobb value (water) 1 minute 92 90 0. 2 of a.d. 0. 2 J6 of a.d. standard polyu ethane commercial grade dispersion product according to Exam 1 e 12 Degree of sizing (seconds) 260 1840 Cobb value (water) 1 minute 35 2k . standard polyuretha e commercial grade dispersion product according to Example 12 Degree of sizing (seconds) 3250 Cobb value (water) .1 minute 21 EXAMPLE 21 Surface sizing is carried out under the same conditions as in Example l'i, except that the size contains of starch and 0. 3 of sizing agent. The polyurethane dispersion described in Example 1 is compared with a product obtained in accordance with DOS 1 , 595 , 602.

The results are set out in Table 9 .

Table 9 product according polyurethane to DOS 1 , 595 , 602 , dispersion Examp 1 e 8 according to Example 1 Degree ,of sizing (seconds) 229 1850 Cobb value (water) 1 minute 70 19

Claims (3)

1. WHAT WE CLAIM IS; 1. A process for the production of cationic polyurethan.es, wherein a nionoineric aliphatic dihydroxy compound containing an aliphatic suhstituent with at least 10 carbon atoms,. i reacted with a polyisocyanate to form a preadduct containing being then converted into an ammonium compound, or the preadduct is chain-extended with a corresponding monomeric aliphatic diol which is already in the form of an ammonium compound.

2. A process as claimed in Claim 1, wherein monomeric substituted aliphatic dihydroxy compounds, in which the two hydroxy groups are connected to one another by at most 7 atoms in the aliphatic chain, are used.

3. A process as claimed in Claims 1 and 2, wherein monomeric substituted aliphatic dihydroxy compounds containing an ^aliphatic substituent with at least 16 carbon atoms are used. k . A process as claimed in any of Claims 1 to 3, wherein a glycerin fatty acid monoester is used as the monomeric substituted aliphatic dihydroxy compound. 5. A process as claimed in Claim wherein the glycerin fatty acid monoester is glycerin monostearate . 6. A process as claimed in Claim wherein the glycerin fatty acid monoester is glycerin behenic acid monoester. 7. A process as .claimed in Claim 1, wherein N-stearyl diethanolamine is used as the monomeric substituted aliphatic dihydroxy compound.. 8. A process as claimed in Claim 1 , wherein 1 , 2- or 1 , 4- dihydroxy octadecane is used as the monomeric substituted aliphatic dihydroxy compound. 9 . Λ process as claimed in any of Claims 1 to 8, wherein hydrogen chloride is used for forming the ammonium compound. ' ' 10. A process as claimed in any of Claims 1 to 9 , wherein/ the aliphatic diol containing tertiary nitrogen is N-methyl diethanolamine. 11 . A process as claimed in any of Claims 1 to 9 , wherein the aliphatic diol containing tertiary nitrogen is 1 , 2-propane-diol-3-dimethylamine. 12. A process as claimed in any of Claims 1 to 11 , wherein a chain-extended product which has heen subjected to intermediate drying (as herein defined) is used for conversion into the ammonium compound. 13. A process as claimed in any of Claims 1 to 12, which is carried out in a solvent. 14. ' A process as claimed in Claim 13 wherein the solvent used is acetone. 15. A process for the production of cationic polyurethanes substantially as herein described and with reference to Examples 1 to 12. s 16^ Cationic polyurethanes obtainable by reacting a monomeric aliphatic dihydroxy compound containing an aliphatic substituent with at least 10 carbon atoms with a poly-isocyanate, followed by chain-extension with an aliphatic diol containing tertiary, nitrogen and conversion of the chain-extended product into an ammonium compound by treatment with an acid or an alkylating agent. 17. Cationic polyurethanes as claimed in Claim 16, wherein the aliphatic suhstituent of the mononieric aliphatic dihydroxy compound contains 16 carbon atoms. 18. Cationic polyurethanes containing structural units of the general formula AMD, the members by which the structure is built up having the following formulae :- 0 0 it II A = C-NH-R- H-C- where It = a divalent, aliphatic, aromatic or araliphatic radical; CHgOR ' -0CHo-CH0R'-CH90- or- -O-CII-CII, where 0 II 11» = C-R", R«> = CnH2n+1 and n = 9 to 21; © D = - O-(CII2)r-NH ' ' « — (CH2)s-0 or where R» ' ' = CnΠ20n ,1 -i-l- ,' —n« = 1^, to 4 '. —r = 2 to 6,' —s = 2 to and X~ is an acid radical · 19. Cationic polyircthanes as claimed in Claim 18, in which the member alternatively has the formul CII— CHo0 "2 or •0— CH-CIL CHr CH20 — Cm' H2m ' + 1 or -0-CUg-CHg- CH2 • 0 wherein, in each case ru or m' has a value of from 10 to 22 , 20 . Cationic polyuretlianes as claimed in Claim 19 , wherein the integer or m' has, in each case, a \ralue of from 16 to 22. 21 . Cationic polyuretlianes according to any of claims 16 to 20 substantially as herein . described and with reference to Examples 1 to 12. 22. Sizing agents for paper containing cationic polyuretlianes according to any of Claims 16 to 21 . 23. Sizing agents for paper containing cationic polyuretlianes produced by a process as claimed in any of Claims 1.to 15 . f