EP0000706A1 - Use of polyimide amine salts as cationic paper surface sizing agents - Google Patents

Abstract

1. The use of salts of organic or inorganic acids with polyimide amines obtained from copolymers of maleic anhydride with hydrocarbon monomers and a mixture of A) a dimine having a tertiary and a primary amino group, and B) ammonia or a primary monoamine as surface sizing agents for paper, characterised in that they are derived from copolymers of maleic anhydride and 2,4,4-trimethyl-1-pentene having average molecular weights of 8,000 to 500,000 and are prepared from these copolymers by reaction with the amine mixture in an anhydrous organic medium at temperatures of 0 degree C to 200 degrees C, the molar ratio of diamine A) to ammonia or monoamine B) being 1:0.3 to 1:2.0 and at least 80% of the anhydride groups having been converted into the corresponding imide groups.

Description

The present invention relates to the use of salts of polyimidamines with organic or inorganic acids for the surface sizing of paper. The corresponding polyimidamines are derived from copolymers of maleic anhydride and 2,4,4-trimethylpentene-1.

From DOS 1 570 914 (= Belgian patent specification 654 889) it is known to use maleic anhydride copolymers with unsaturated monomers, such as e.g. React styrene, vinyl and allyl ethers etc. and with unbranched α-olefins as comonomers, with a diamine and optionally a monoamine. The diamine in question carries both a primary and a tertiary amino group. The reaction takes place in inert organic solvents. The polyimidamines obtained are treated with epihalohydrins, e.g. Epichlorohydrin, quaternized. These quaternized products are used in aqueous solution as surface sizing agents for paper. The molecular weights of the polymers are between 2000 and 5000. Yellowing is observed at higher molecular weights, and the sizing effect is inadequate for very low molecular weight products (MW <2000).

From German Patent 1,595,704 it is known to react maleic anhydride homo- or copolymers with a mixture of diamines with a primary and a tertiary amino group and primary monoamines. Here, an anhydride group has approximately one primary amino group. the reaction is carried out in aqueous or alcoholic-aqueous acids at elevated temperatures. Here, based on tertiary amino groups in the amine mixture, 25 to 350 mol percent of acid equivalents are used. The polyimidamines represented in this way are suitable in neutral form as emulsifiers and dispersants for the production of coatings and protective coatings. They are also suitable as water repellents and intermediates for crop protection agents and pharmaceuticals.

To produce paper sizing agents, such polyimidamines must either be mixed with non-cationic polymers in accordance with German Patent 1,621,688, or converted into graft polymers with special, olefinically unsaturated graft monomers in accordance with German Patent 1,621,689. As can be seen from the comparative tests of German patent 1,621,688, the polyimidamines alone have a significantly lower, inadequate sizing effect.

Surprisingly, it has now been found that polyimidamines of the type mentioned, which are derived from copolymers of maleic anhydride and 2,4,4-trimethylpentene-1 by reaction with a mixture of a diamine having tertiary and primary amino groups and a primary monoamine, directly in the form of a aqueous solution of their salts with organic or inorganic acids can be used as an excellent surface sizing agent for paper.

The invention thus relates to the use of salts of organic or inorganic acids with polyimidamines, which differ from copolymers of maleic anhydride and 2,4,4-trimethylpentene-1 by reaction with a mixture of a diamine with tertiary and primary amino group and ammonia or derived from primary monoamine as a surface sizing agent for paper and paper-like materials. '

The copolymers of maleic anhydride with 2,4,4-trimethylpentene-1 are preferably of equimolar and alternating structure. The average molecular weights are between 8,000 and 500,000, preferably between 10,000 and 60,000, determined by membrane osmometry. The preferred copolymers have intrinsic viscosities of 0.08 to 0.3 dl / g, measured in N, N-dimethylformamide at 25 ° C.

Copolymers with intrinsic viscosities below 0.08 dl / g lead to considerably less effective sizing agents for paper. Products that are too high in molecular weight result in viscosities of the sizing agent that are too high and thus poorer processability.

To prepare the polyimidamines, the copolymers of maleic anhydride and 2,4,4-trimethylpentene-1 are mixed with a mixture in an anhydrous organic medium
A) a diamine with primary and tertiary amino group and B) ammonia or a primary monoamine
implemented at temperatures from 0 ° to 250 ° C and thereby converting at least 80%, preferably more than 85%, of the anhydride groups of the copolymers into the corresponding imide groups.

The molar ratio of diamine (A) to monoamine (B) is 1: 0.3 to 1: 2.0.

und als Monoamine solche der allgemeinen Formel

eingesetzt.Diamines are those of the general formula

and as monoamines those of the general formula

used.

In the above formulas, R denotes a linear or branched aliphatic chain containing 2 to 12, preferably 2 to 6 carbon atoms, which may optionally also contain oxygen or sulfur atoms. The substituents R ₁ and R _{2 of} the tertiary amino group can be the same or different and represent aromatic radicals, such as phenyl, toluyl, xylyl, chlorophenyl, nitrophenyl, 4-dimethylaminophenyl, preferably phenyl, toluyl, xylyl, araliphatic radicals, such as benzyl, 2- Phenylethyl, preferably benzyl; Alkyl radicals with 1 to 12, preferably 1 to 6 carbon atoms, or the two substituents together represent a 5- or 6-membered cyclic ring which may contain an oxygen or sulfur atom.

Preference is given to diamines whose primary and tertiary amino groups are separated from one another by a linear alkylene chain from 2 to 6 methylene groups and whose tertiary amino group is substituted by linear C ₁ -C ₄ -alkyl radicals. 1-Amino-3-dimethylaminopropane is particularly preferred.

The substituent R ₃ represents an aliphatic or cycloaliphatic, saturated or unsaturated, optionally substituted hydrocarbon radical.

Preferred monoamines are ammonia and / or aliphatic primary monoamines with 1 to 18 carbon atoms or cycloaliphatic monoamines with 5 to 8 carbon atoms. Particularly preferred monoamines are, for example, methylamine, ethylamine, n-propylamine, n-butylamine, sec. Butylamine, iso-butylamine, tert. Butylamine, n-hexylamine, 2-ethylhexylamine, cyclohexylamine and dehydroabietylamine.

1-Amino-3-dimethylaminopropane and ethylamine in a molar ratio of 1: 1 to 1: 1.6 are particularly preferably used as the amine mixture.

The mixture of the diamines (A) and the monoamines (B) is used in an approximately equimolar amount, but preferably in a slight excess, based on the anhydride groups of the starting polymer; the amine mixture used should preferably contain 1.0-1.5 mol of primary amino groups, based on one mol of anhydride groups of the polymer. The excess of amine is therefore added in order to achieve the most complete possible imidization, which should be at least 80%, preferably more than 85%. Lower imidized reaction products are poorly water-soluble and show insufficient sizing effects on paper. In the mixture of diamine (A) and primary amine (B) the molar ratio of diamine to monoamine should be between 1: 0.3 and 1: 2.0. The two amine components can be reacted as a mixture or in succession. Suitable solvents include organic, alkyl and halogen-substituted aromatic solvents such as benzene, toluene, m-, o- or p-xylene or mixtures thereof. They are able to solve both maleic anhydride-2,4,4-trimethylpentene-1 copolymers and their reaction products, the polyimidamines.

To produce the sizing agents and to dissolve the polyimidamines in aqueous systems, they must be converted into salt form. Inorganic and organic acids are suitable for this, of which 100 to 500 mol percent, based on the tertiary amino groups contained in the chemically bound amine mixture, are added. Particularly suitable acids are formic acid, acetic acid, propionic acid, lactic acid, hydrochloric acid, nitric acid and sulfuric acid, preferably formic acid and acetic acid. Water is generally used as the solvent. After the reaction has ended, the polyimidamine salts are present in a 5 to 30% solution. No gelling of the products is observed, as is described in the Belgian patent specification 654 889 in the higher molecular weight range above 5000.

The copolymer of maleic anhydride and 2,4,4-trimethylpentene-1 is advantageously imidized in two stages. In the first stage, the copolymer is suspended or dissolved in the organic solvent at temperatures between 0 ° C. and 50 ° C. and the amine mixture is added dropwise at these temperatures with stirring. Monoamide is predominantly formed in this reaction stage. In the second reaction stage, the reaction mixture is brought to a temperature of 130 ° C. to 200 ° C. with stirring. In this step, carried out thermally, optionally with the aid of Katalysaroren, such as p-toluenesulfonic acid, pyridine, etc. elimination of water the imidization of at least 80%, preferably more than 85% of the original _A nhy- dridgruppe.

The organic polymer solution can be converted into an aqueous solution, for example, in such a way that the organic solution is distilled off at the same time of the organic solvent continuously in a heated template with dilute aqueous acid.

In contrast to German Patent 1,595,704, the copolymers of maleic anhydride and 2,4,4-trimethylpentene-1 converted to polyimidamine salts are used as surface sizing agents for paper, which have excellent sizing effects directly in aqueous solution without any additives. In contrast to water repellents that have a water-repellent effect, sizing agents are products that ensure that paper is labeled with ink but prevent it from bleeding. Thus, while water repellents are water-repellent and water-insoluble, the sizing agents according to the invention are water-soluble.

In addition, it was found that the manufacturing process for polymimidamines described in German Patents 1,595,704 and 1,621,688 is not suitable for the sizing agents to be used according to the invention, since this process gives products which by far do not have the desired high degree of imidization of at least 80 % to reach. Accordingly, salts of these products with acids cannot be used as surface sizing agents for paper.

An improvement over the German patent 1 621 688, in which cationic sizing agents are used in the form of dispersions, is the use according to the invention of the sizing agents in homogeneous aqueous solution. They are easy to process, guarantee, in contrast to heterogeneous sizing systems, absolute homogeneity of the sized paper and show an excellent sizing effect on all papers, with particular emphasis being placed on the chalk-containing paper. The used according to the invention Sizing agents are clearly superior to all conventional sizing agents.

In the following examples, the parts given are parts by weight, unless stated otherwise.

Example A

105 parts of alternating copolymer of maleic anhydride and 2,4,4-trimethylpentene-1 (average molecular weight M _GPC ¹⁾ : 47,000) in 260 parts of xylene are introduced into a three-necked flask with a water separator. It is dissolved with stirring at 120 ° C. and 26 parts of dehydroabietylamine, dissolved in 174 parts of xylene, and 63 parts of 1-amino-3-dimethylaminopropane are added dropwise. Then allowed to react for 10 hours on a water separator at 150-160 ° C. The amount of water separated in the azeotropic distillation with xylene is regarded as an approximate conversion measure (8.5 ml = 94% conversion). After the polyimide formation has ended, 50 parts of formic acid are added dropwise. The majority of the xylene is decanted from the precipitated polyimidamia salt and the remaining solvent is distilled off azeotropically with water vapor. At the same time, an aqueous solution with a solids content of 9.1 percent by weight is obtained.

Example B

105 parts of a copolymer of maleic anhydride and 2,4,4-trimethylpentene-1 (M _GPC = 47000) are dissolved in 260 parts of xylene at 120 ° C. A mixture of 45 parts of stearylamine and 34 parts of 1-amino-3-dimethylaminopropane, dissolved in 174 parts of xylene, are added dropwise to the polymer solution with stirring. The highly exothermic reaction initially gives a product which is insoluble in xylene, probably the monoamide, which, with stirring for 10 hours on a water separator at 150-160 ° _C. , releases the soluble polyimidamine with elimination of water. This can be recognized very easily by the IR double band characteristic of cyclic five-ring imides at the wave numbers 1 ₆₉₀ cm ^-1 and 1770 cm ^-1 , while the partial band characteristic of cyclic five-ring anhydrides at 184 ₀ cm ^-1

¹ ) M _GPC = molecular weight determined by gel permeation chromatography

disappears. 34.5 parts of formic acid are added dropwise. The organic solvent is distilled off with steam at 100.degree. The aqueous solution has a solids content of 14.9% by weight.

Example C

As example B, except that instead of the amine mixture there, a mixture of 46 parts of dodecylamine and 26 parts of 1-amino-3-dimethylaminopropane, dissolved in 174 parts of xylene, is added dropwise. The aqueous solution has a solids content of 10.5% by weight.

Example D

As example B, except that a mixture of 15 parts of hexylamine and 39 parts of 1-amino-3-dimethglaminopropane without solvent is added dropwise instead of the amine mixture there. The aqueous solution has a solids content of 13.5% by weight.

Example E

105 parts of copolymer of maleic anhydride and 2,4,4-trimethylpentene-1 are dissolved in 435 parts of xylene at 120 ° C. and a mixture of 22 parts of cyclohexylamine and 28 parts of 1-amino-3-dimethylaminopropane is added dropwise. 8.3 parts of water are separated off on the water separator (= conversion of 92%), then 35 parts of formic acid are added and steam distillation is carried out at 100 ° C. The aqueous solution has a solids content of 7.9%.

Example F

525 parts of copolymer as in Example A, 200 parts of xylene, 91 parts of n-butylamine and 128 parts of 1-amino-3-dimethylaminopropane are introduced into a stainless steel stirred autoclave. With stirring, is heated to 50 ° C, held for 2 hours at this temperature and 3 hours at 13 _{C 0} ° ge stirs. 42.5 parts of water (= 94% conversion) are obtained on the water separator. 250 parts of formic acid are added dropwise to the solution and the xylene is distilled off azeotropically with water vapor. The aqueous solution has a solids content of 11.4%.

Example G

525 parts of copolymer as in Example A, dissolved in 525 parts of toluene, are placed in a stirred autoclave together with 1650 parts of xylene and 85 parts of 1-amino-3-dimethylaminopropane and 98 parts of n-propylamine. The mixture is stirred at 50 ° C. for 3 hours and at 130 ° C. for 7 hours. 40 parts of water are separated off on the water separator (= 89% conversion). 173 parts of formic acid are added dropwise to the solution of the polyimidamine and then steam distillation is carried out again. The solids content of the aqueous solution is 6.5%.

Example H

Like example 6, but instead of n-propylamine and 1-amino-3-dimethylaminopropane, a mixture of 126 parts of ethylamine and 112 parts of 1-amino-3-dimethylaminopropane. The solids content of the aqueous solution is 9.6%.

Example I

814 parts copolymer as in Example A are introduced, together with 3100 parts xylene, 181 parts of 1-amino-dimethylaminopropane and 112 parts Äth ^y lamin in a stirred autoclave. The mixture is then stirred at 50 ° C. for 3 hours and at 130 ° C. for 7 hours. 65 parts of water are separated off on the water separator (= 93% conversion).

380 parts of formic acid are added dropwise to the solution of the polyimidamine. This is followed by steam distillation. The solids content of the aqueous solution is 10.8%. The viscosity of the solution at 25 ° C is approx. 30 cP, measured in a Haake-Viscotester.

The use of sizing agents A - H is described by way of example below:

A solution of 5% by weight starch (Perfectamyl® A 4692 from AVEBE) and 0.25 or in some cases 0.5% by weight of the sizing agent to be tested (calculated as active substance) was used as the sizing liquor for the surface sizing 94.75 and 94.5 wt .-% water used.

A laboratory size press from Werner Mathis, Zurich, type HF was used for the sizing. The size liquor had a temperature of approx. 20 ° C in the size press. The paper was fed at a speed of 4 m / min. pulled through.

The surface-sized papers were dried on a drying cylinder within 45 seconds at approx. 100 ° C. Before the sizing. testing, the papers were conditioned for 2 hours at room temperature. Sections of the paper were then pre-weighed, immersed in water at 20 ° C. for 1 minute, pressed once between filter paper using a 10 kg rolling weight and weighed back. The value for the water absorption on both sides in g / m ^{2 was} calculated from the weight difference. The lower the water absorption, the better the effect of the tested sizing agent. Sizing is good when water absorption of approx. 40 g / m ² and below is achieved.

Example 1:

This example is intended to show that good sizing effects can be achieved with the described sizing agents on unsized papers from bleached cellulose. The base paper used was made from bleached sulfite pulp with the addition of 3% china clay (calculated as ash) at pH 6.8 and had a weight per unit area of 70 g / m ² .

Example 2:

This example shows the good effectiveness of the sizing agents described on wood pulp-containing papers. The base paper used was made from 50% bleached wood pulp and 50% bleached sulfite pulp with the addition of 11% china clay (calculated as ash) at pH 5 and had a weight per unit area of 70 g / m ² .

Example 3:

This example demonstrates the good effect of the sizing agents described on papers containing calcium carbonate.

The base paper used was (expressed as ash) of 50% of bleached spruce and 50% bleached sulphate pulp book with the addition of 14% precipitated calcium carbonate at ^pH 6.8 prepared and had a basis weight of 70 g / m ^2.

Example 4

In this example, one of the products described, sizing agent J, is compared with a cationic "sizing agent M", which represents the prior art and corresponds in its composition to the products described in DT-OS 1 621 688.

• Rohpapier I: Wie in Beispiel 1 beschrieben
• " II: Wie in Beisoiel 3 beschrieben
• III: Gebleichter Zellstoff, ca. 12 % Talkum-Asche, 1 % Aluminiumsulfat, ungeleimt; ca. 80 g/m².
• " IV: Gebleichter Zellstoff, ca. 7 % China Clay-Asche, vorgieimt mit 0,1 % Harzleim und 0,5 % Aluminiumsulfat; ca. 75 g/_m ².

The following base papers were used:

• Base paper I: As described in Example 1
• "II: As described in example 3
• III: bleached cellulose, approx. 12% talc ash, 1% aluminum sulfate, unsized; approx. 80 g / m ² .
• "IV: bleached pulp, approx. 7% china clay ash, pre-glued with 0.1% resin glue and 0.5% aluminum sulfate; approx. 75 g / _m ² .

The degree of sizing against ink was determined using the Hercules Sizing Tester, in accordance with the operating instructions of the manufacturer Hercules Inc., Wilmington, Delaware, USA. The time is measured in seconds until the remission drops to 75% of the remission value of paper when the test ink is applied to the paper and penetrates through the paper. The longer the measured time, the better the degree of sizing.

It can be clearly seen here that the size effect of size J for all the unsized and pre-size papers tested considerably exceeds that of the commercially available size M at the three practical concentrations chosen.

Example 5

This example shows the usability of the sizing agents described in the pulp.

In a paper stock made of 50% birch sulfate, 30% pine sulfate and 20% spruce sulfite pulp, 1% and 2% sizing agent (active substance, respectively) were obtained with a consistency of 0.5% and a pH of 6.9 with stirring on dry pulp) added.

Immediately afterwards, paper sheets were formed on a laboratory sheet former, which were dried at 100 ° C. and had a weight per unit area of about 100 g / m ² .

The sizing effect was determined by the "ink float sample" common in the paper industry, i.e. by placing the papers on test ink (Pelikan 4001).

For comparison, a cationic "size M" was again used, which corresponds to the products described in DT-PS 1 621 688.

Claims (6)

1. Use of salts of organic or inorganic acids with polyimidamines which are derived from copolymers of maleic anhydride and 2,4,4-trimethylpentene-1 with average molecular weights of 8000 to 500,000 and from these by reaction in an anhydrous organic medium at temperatures of 0 ° C to 200 ° C with a mixture of A) a diamine with tertiary and primary amino group and B) ammonia or a primary monoamine are obtained, the molar ratio of A) to B) being 1: 0.3 to 1: 2.0 and at least 80% of the anhydride groups having been converted into the corresponding imide groups, as surface sizing agents for paper. 2. Use of paper sizes according to claim 1, characterized in that they are derived from equimolar and alternating copolymers of maleic anhydride and 2,4,4-trimethylpentene-1 with average molecular weights of 10,000 to 60,000, the intrinsic viscosities of 0.08 up to 0.3 dl / g (measured in dimethylformamide at 25 ° C). 3. Use of paper sizing agents according to claim 1, characterized in that the polyimidamines by reaction with an amine mixture Ä) a diamine of the formula

NH ₂ , where R is a linear alkylene chain of 2 to 6 methylene groups and R ₁ and R _{2 are} linear C ₁ -C ₄ alkyl radicals and B) a primary monoamine from the group methylamine, ethylamine, n-propylamine, n-butylamine, n-hexylamine, cyclohexyamine, 2-ethylhexylamine and dehydroabietylamine have been obtained. 4. Use of paper sizing agents according to claim 3, characterized in that an amine mixture of 1-amino-3-dimethylaminopropane and ethylamine in a molar ratio of 1: 1 to 1: 1.6 has been used. 5. Use of paper sizes according to claim 1, characterized in that they are imidized to more than 85%. 6. Use of paper sizing agents according to claim 1, characterized in that salts of the polyimidamines with formic acid, acetic acid, propionic acid, lactic acid, hydrochloric acid, nitric acid or sulfuric acid are used.