EP0052733B1 - Microcapsules containing wax compositions, their preparation and use - Google Patents

Description

The invention relates to wax compositions containing microcapsules on the basis of microcapsules with a wall material made of melamine-formaldehyde condensates, and to the production and use of these wax compositions.

Wax compositions containing microcapsules have long been known from the patent literature. Wax compositions containing microcapsules with melting points between 55 and 175 ° C. are described in US Pat. Nos. 30 16 308 and 30 79 351. The masses can by various methods, e.g. B. applied by printing on paper as a carrier. The solidifying wax binds the microcapsules to the carrier. The dry microcapsules contained by spray drying the emulsions described in the US patent have diameters of 1 to 50 J.1.m and are therefore not suitable for the production of pressure-sensitive recording materials. The large capsules are destroyed when printing or coating with layers approximately 5 µm thick. Large capsules are also partially destroyed in the manufacture of the wax compositions containing microcapsules by the relatively high temperatures and by the shear forces required for homogenization. This results in a low intensity of the copy obtained and a gradual staining of the CF layer (recipient layer) in the form set.

JP-A-73 12 255 describes a wax composition containing microcapsules for spot printing. The wax mass is obtained by mixing dry microcapsules with a wax melt in the presence of nonionic surfactants. Capsules are those with wall materials made of gelatin, polymers or melamine-formaldehyde condensates. Paper coated with this mass should not give any discoloration during storage in the form set.

DE-A-2719 914 describes pressure-sensitive carbonless copy papers based on wax melts containing microcapsules. The wax composition used for coating is produced by heating the water-insoluble, functional groups-bearing wax-like substances or the non-polar waxes with anionic dispersants to above the melting temperature and dispersing the dry microcapsules in this melt. According to the information in the description, microcapsules with wall material based on hydroxypropyl cellulose, methyl cellulose, carboxymethyl cellulose, melamine formaldehyde, polyfunctional isocyanates and their prepolymers, polyfunctional acid chlorides, polyamines, polyols, epoxides or mixtures thereof are suitable for these compositions. Microcapsules with wall material made of hydroxypropyl cellulose crosslinked with polyfunctional isocyanates are particularly preferred.

The wax composition can also be prepared by adding the aqueous microcapsule dispersion to the wax melt and distilling off the water in vacuo. In this case, the aqueous capsule dispersion must be added continuously to the melted wax to the extent that the water distills off, so that the mass is practically free of water. Hydroxypropyl cellulose capsules are not stable at 70 ° C in the presence of water, while dry capsules in the absence of water are said to be stable at approximately 95 ° C for approximately 18 hours. However, it can be seen from Table I in Example II that the microcapsules based on hydroxypropyl cellulose, crosslinked with polyisocyanate and post-cured with melamine-formaldehyde and gelatin in the wax melt at 90 ° C. are considerably permeable and accordingly have a high degree in thermogravimetric analysis Show loss.

DE-A-2818 976 also describes hot-meltable wax compositions containing microcapsules. The wax compositions are prepared by the process already given in DE-OS 2719 914, Example 1, by adding the aqueous microcapsule dispersion to the wax melt and removing the water in vacuo. The dispersion should be added to the extent that the water is removed. In order to achieve a rapid removal of the water, mixing with the wax melt is carried out continuously with stirring in a thin-film evaporator.

In the case of DE-A-28 18 976, water-soluble waxes and resins such as polyethylene oxide wax and polyvinylpyrrolidone can also be used as the “suspending medium” (wax). The carbon-free carbonless papers obtained with the wax compositions produced in this way have a reduced copy performance compared to corresponding papers with wax compositions which were produced with spray-dried microcapsules.

Since the coating compositions of DE-A 28 18 976 and DE-A-2719 914 are more or less lightly colored, the coated side is colored accordingly in the case of white paper. Since opacifiers such as titanium dioxide or clay form lumps in the wax melts and are difficult to disperse, the color of the wax application could not be masked in this way. This problem is solved by DE-A-28 20 600 by adding inorganic pigment to the aqueous microcapsule dispersion and isolating this mixture by spray drying. A flowable powder is obtained, which is then dispersed in the wax melt.

Furthermore, from DE-A-28 26 939 microcapsules with secondary capsule walls are known, in which the capsule wall primarily formed from hydroxypropyl cellulose and a di- and polyisocyanate is aftertreated in a subsequent step with phenol and aldehyde. The polymer formed by condensation is deposited on the wall formed first. These capsules are said to have advantages in the manufacture of microcapsule-containing wax compositions, since the capsules are made by Filtration separated from the aqueous phase and can be added to the known wax melts in this form. However, only in Example 2 is a coating mixture described. According to the information in Example 3, the particle sizes of the capsules are from 3.1 to above 12.3 μm (25% are 12.3 μm), the capsules being in the form of agglomerates.

It follows from the prior art that it has not yet been possible to produce hot-meltable wax compositions containing sufficiently stable microcapsules.

The object of the present invention was to find stable wax compositions containing microcapsules for the application by the hot-melt process.

• a) 20 bis 55 Gew.-% Mikrokapseln,
• b) 79 bis 30 Gew.-% Wachs oder ein Gemisch verschiedener Wachse mit einem Schmelzpunkt zwischen etwa 50 und 140 °C,
• c) 1 bis 10 Gew.-% mindestens einem nichtionischen Emulgator, einem Alkalimetallsalz von Montanwachssäuren oder einem Gemisch aus (a) mindestens einem nichtionischen Emulgator und (ß) mindestens einem Alkalisalz von Montanwachssäuren, von C_1O- bis C_2o-Fettalkoholsulfaten und/oder von C_1o- bis C₂₀-Alkansulfonaten,
• d) 0 bis 20 Gew.-% Pigmente und/oder Füllstoffe,
• e) 0 bis 60 Gew.-% flüchtige Anteile und ggf.
• f) weitere in solchen Wachsmassen übliche Mittel,

bestehen, wobei das Wandmaterial der Mikrokapseln (a) ein polymeres Melamin-Formaldehyd-Kondensat ist, das durch Kondensation von Melamin mit Formaldehyd, von Methylolmelaminen und/oder deren Methyläthern bei einem Verhältnis von Melamin zu Formaldehyd von 1 : 2 bis 1 : 6 bei pH 3,5 bis 5,5 und Temperaturen von 60 bis 100 °C und 2 bis 10 stündigem Aushärten bei 60 bis 100 °C erhalten wird und wobei das Verhältnis Kernmaterial zu Wandmaterial in der Kapsel 1 : 15 bis 1 : beträgt und die Mikrokapseln einen Durchmesser von 2 bis 10 µm aufweisen.It has been found that wax compositions which are excellently suitable for the purpose described and which do not have the difficulties known from the prior art are present if they - based on (a + b + c) - are present

• a) 20 to 55% by weight of microcapsules,
• b) 79 to 30% by weight of wax or a mixture of different waxes with a melting point between about 50 and 140 ° C.,
• c) 1 to 10% by weight of at least one nonionic emulsifier, an alkali metal salt of montan wax _acids or a mixture of (a) at least one nonionic emulsifier and (β) at least one alkali salt of montan wax _acids , of C ₁₀ to C ₂₀ fatty _alcohol sulfates and / or from C ₁₀ to C ₂₀ alkanesulfonates,
• d) 0 to 20% by weight of pigments and / or fillers,
• e) 0 to 60% by weight of volatile components and, if appropriate
• f) other agents customary in such wax compositions,

exist, wherein the wall material of the microcapsules (a) is a polymeric melamine-formaldehyde condensate, which by condensation of melamine with formaldehyde, of methylolmelamines and / or their methyl ethers at a ratio of melamine to formaldehyde of 1: 2 to 1: 6 pH 3.5 to 5.5 and temperatures of 60 to 100 ° C and 2 to 10 hours of curing at 60 to 100 ° C and where the ratio of core material to wall material in the capsule is 1:15 to 1: and the microcapsules have a diameter of 2 to 10 µm.

For the wax composition, it is essential to the invention that it contains microcapsules, the wall material of which 1) consists of melamine-formaldehyde condensates and 2) the wall material has been produced under the conditions specified above.

The wax compositions according to the invention are thermally stable even in the presence of water and, after being applied to the carrier material, together with CF layers, give strong, sharp copies. The CF layers are not stained in form sets even after prolonged storage. A discoloration of the CF layer does not occur or practically does not occur if the wax composition containing microcapsules is applied directly to the CF layer. The wax compositions according to the present invention can be applied over the whole or part of the surface simultaneously or after printing on the carrier material by known methods. Clean and distortion-free smooth support materials are obtained even if the wax composition contains up to 20% by weight of water, based on (a + b + c).

The microcapsules contained in the wax compositions according to the invention have a wall which consists of highly crosslinked melamine-formaldehyde condensates. The ratio of wall material to core material is 1:15 to 1: 2, preferably 1:10 to 1: 4. The most advantageous ratio depends on the capsule size. The larger the capsule, the more wall material is required. The microcapsules required for the wax compositions according to the invention are obtained by curing the capsules obtained primarily. The curing takes place by heating the aqueous capsule dispersions to 60 to 100, preferably 70 to 90 ° C. for 2 to 10, preferably 3 to 6 hours. This treatment increases the thermal resistance and the resistance to water in the wax melts. In this treatment, the formaldehyde content in the aqueous phase is increased. The resulting formaldehyde can be bound with ammonia, amines or other compounds that react with formaldehyde, such as ethylene urea.

The primary wall is obtained by condensation of melamine with formaldehyde, methylolmelamines, methylolmelamine methyl ethers or mixtures thereof at a ratio of melamine to formaldehyde of 1: 2 to 1: 6, preferably 1: 3 to 1: 6.

Microcapsules with diameters from 2 to 10, in particular from 2 to 8 μm are suitable for the intended use of the wax compositions.

The production of the primary microcapsules is known. All microcapsules with walls made of melamine-formaldehyde condensates which are obtainable by known processes are suitable for curing if they meet the criteria specified above. Preferred are microcapsules which are obtained according to the method of older priority EP-A-26914, which has not been previously published.

The wax compositions according to the invention contain - based on (a + b + c) - 20 to 55, preferably 30 to 45% by weight of microcapsules (a). The higher the content of (a) in the wax mass, the more intense the copies become. On the other hand, the capsule is protected against destruction as the proportion of wax (b) and pigment (d) increases. Since the viscosity of the liquid wax mass also increases with increasing content of (a), waxes with a high content of (a) which have low viscosity melts will be used for wax masses. It was found that minor Quantities, e.g. B. 2 to 10 wt .-% of water in the melt have a viscosity-reducing effect without disadvantages in use or on the carrier material coated with such wax materials such as paper.

Particularly suitable waxes are the water-insoluble waxes usually used in wax compositions for hot carbon processes, both on their own and in the form of mixtures of different waxes with a melting point of about 50 to 140 ° C. Bright waxes are preferred for the wax compositions according to the invention. Natural and synthetic waxes can be considered. In particular, e.g. B. To name: plant waxes, such as candelila wax, carnauba wax; Hydrocarbon waxes such as paraffins, ozokerite and microcrystalline waxes; Montan wax and waxes made from it, such as montanic acids and their esters, polyethylene waxes, oxidized microcrystalline waxes and ester waxes.

In addition, the mixtures can also contain hydrophilic waxes, such as polyethylene glycols, polypropylene glycols or their mixed block copolymers.

The intensity of the copy depends on the wax mixture used as a binder, whereby not only the hardness but also the wettability plays a role. The intensity of the copy gets better with paraffins as the melting point of the paraffins increases (e.g. from 52 to 69 ° C.). Ester waxes based on ethylene glycol or butanediol and montanic acids as binders give more intense copies than with paraffins and / or montanic acids. The intensity of the copy can also be improved by adding ethylene oxide adducts.

So that the microcapsules are dispersed (distributed) homogeneously in the wax melt without a substantial proportion of agglomerates, the wax melt contains 1 to 10% by weight, based on (a + b + c), as c) one or more nonionic emulsifiers, at least one Alkali metal salt of montan wax acids or a mixture of (a) at least one nonionic emulsifier and (ß) at least one alkali metal _salt of montan wax _acids , from C _1o to C _zo fatty alcohol sulfates and / or from C ₁₀ to C ₂₀ alkane sulfonates.

Suitable nonionic emulsifiers are for (c), mainly water-soluble ethylene oxide adducts of C ₁₂ - to C ₂₀ -alkanols or C ₁₂ - to C _2o -alkenols having from 13 to 30, preferably 15 to 25 moles of EO per mole of alcohol proven. In many cases it can be advantageous up to 50% of the water-soluble emulsifiers by oil-soluble ethylene oxide adducts with alkylphenols with 1 to 3 alkyl groups, C ₁₂ to C ₂₀ alkanols or C ₁₂ to C _2o alkenols with 3 to 10, preferably 4 to 8 EO per mole of alcohol or phenol to replace.

Also included as (c) are alkali metal salts of montan wax acids (also called montan acids) and mixtures of (a) a nonionic emulsifier and (ß) alkali metal salts of montan wax acids, C ₁₀ to C ₂₀ fatty alcohol sulfates and / or from C ₁₀ to C ₂₀ Alkane sulfonates into consideration.

As fatty alcohol sulfates, which are salts of sulfuric acid semiesters of fatty alcohols, e.g. For example, to name those derived from decanol, lauryl alcohol (dodecanol-1), tetradecanol-1, hexadecanol-1 (palmityl alcohol), octadecanol-1 (stearyl alcohol) or from technical C _10/12 -, C _12/14 -, Derive C _14/18 alkanol mixtures.

As C ₁₀ - to C ₂₀ alkanesulfonates, the alkali metal salts of z. B. decane, dodecane, tridecane, tetradecane, hexadecane and octadecane sulfonic acid or mixtures of C _10/12 -, of C _12/16 alkanesulfonic acids into consideration.

Above all, the sodium, potassium and lithium salts are to be mentioned as alkali metals, of which the sodium and potassium salts are preferred.

The alkali metal salts of montan wax acids are obtained by neutralizing the montan wax acids obtained by chromic acid oxidation of montan wax with the corresponding bicarbonates, carbonates or also hydroxides. The alkali metal salts of montan wax acids can be prepared in isolation or previously in the wax melt to be used.

Of the water-soluble emulsifiers (c), adducts of stearyl alcohol, tallow fatty alcohol or partially unsaturated C _16/18 alkanol mixtures and 15 to 25 moles of EO per mole of alcohol are particularly preferred.

As the (c) alkali metal salts of montan wax acids, and mixtures of (a) are nonionic emulsifying agents, especially those mentioned above and (ß) alkali metal salts of montan wax acids, of C _lo - C ₂₀ -Fettalkoholsulfaten and / or of C _1o - to C _2o - Alkanesulfonates are particularly preferred.

Of these, the alkali metal salts of montan wax acids and mixtures of these alkali metal salts and EO adducts of 15 to 25 moles of ethylene oxide per mole of alcohol in stearyl alcohol, tallow fatty alcohol and / or in mixtures of partially unsaturated C _16/18 alkanols are very special because of the particularly good dispersing action prefers.

If sufficient amounts of (c) are used, the microcapsules in the wax are largely or almost completely in the form of individual particles. The amount of (c) is - based on (a + b + c) - 1 to 10, preferably 3 to 10% by weight, in particular 4 to 9% by weight.

To improve the stability of the microcapsules in the wax coating, fillers or mixtures thereof, such as are also added to aqueous coating colors containing microcapsules, can be added to the wax composition. These funds are intended for the premature unintentional destruction of capsules, for. B. prevent when rubbing the leaves against each other. As pigments come e.g. B. titanium dioxide, barium sulfate, Blancfixe and as fillers z. B. starch or protein in Form of grains or spherical particles of urea-formaldehyde condensates with particle diameters between 2 and 20 microns into consideration.

Because of the high stability of the microcapsules to heat, even in the presence of water, the wax melt can contain up to 60, preferably 0 to 20% by weight, based on (a + b + c), of water as volatile component (s). The water content has an advantageous influence on the viscosity of the wax mass, which is reduced and on the dispersion of microcapsule agglomerates during incorporation.

Other agents (f) which are customary in wax compositions for the hot-melt process are those for regulating the viscosity. The viscosity of the mass can be increased by adding polyethylene waxes, oxidized polyethylene or by adding petroleum jelly, mineral oil, stearylamide, stearic acid esters, sodium stearate, potassium stearate, barium stearate, sodium palmitate, potassium palmitate, sodium oleate, potassium oleate, calcium stearate, zinc stearate, A-wax, in which Melt soluble polymers or mixtures thereof can be reduced.

• 1) Die Kapseln werden aus der wäßrigen Dispersion isoliert, z. B. durch Aufrahmen und Filtrieren oder durch Zentrifugieren. Die erhaltenen feuchten Kapseln, die ca. 40 % Wasser enthalten, werden in die Emulgiermittel enthaltende Wachsschmelze eingetragen. Das eingebrachte Wasser kann gegebenenfalls entfernt werden, z. B. durch Destillation im Vakuum. Das Wasser kann jedoch ohne Nachteile in der Wachsmasse verbleiben. Die Mikrokapseln liegen in der Wachsmasse in Form von Einzelkapseln vor.
• 2) Die Kapseln werden in der Dispersion gefällt bzw. geflockt, z. B. durch Zugeben von Salzen, insbesondere von Salzen mit mehrwertigen Kation oder durch Zugeben von langkettigen Aminen wie Stearylamin, Diethylhexylamin, Dimethyl-C₁₃ bis C_1s-alkylamin oder 2-Ethylhexylamin, vorzugsweise bei pH 7,0. Die geflockten Kapseln werden isoliert, z. B. durch Zentrifugieren und wie bei 1) in die Wachsschmelze eingearbeitet.
• 3.1) Die Mikrokapseln werden durch Sprühtrocknung aus der Dispersion isoliert. Die so erhaltenen Pulver bestehen zum überwiegenden Teil aus agglomerierten Mikrokapseln und sind daher in der Wachsschmelze schwieriger zu dispergieren als die nach 1) oder 2) isolierten feuchten Mikrokapseln.

The wax compositions according to the invention can be produced by various processes.

• 1) The capsules are isolated from the aqueous dispersion, e.g. B. by creaming and filtering or by centrifugation. The moist capsules obtained, which contain about 40% water, are introduced into the wax melt containing emulsifiers. The water introduced can optionally be removed, e.g. B. by distillation in vacuo. However, the water can remain in the wax mass without disadvantages. The microcapsules are in the wax mass in the form of individual capsules.
• 2) The capsules are precipitated or flocculated in the dispersion, e.g. B. by adding salts, in particular salts with polyvalent cation or by adding long-chain amines such as stearylamine, diethylhexylamine, dimethyl-C ₁₃ to C _1s -alkylamine or 2-ethylhexylamine, preferably at pH 7.0. The flocked capsules are isolated, e.g. B. by centrifugation and as in 1) incorporated into the wax melt.
• 3.1) The microcapsules are isolated from the dispersion by spray drying. The powders obtained in this way consist predominantly of agglomerated microcapsules and are therefore more difficult to disperse in the wax melt than the moist microcapsules isolated according to 1) or 2).

The dispersion of the dry capsules can be made considerably easier by adding a little water to the wax melt.

The microcapsules isolated by spray drying are preferably dispersed in the wax melt in the presence of alkali metal salts of montan wax acids or of mixtures of (a) nonionic emulsifiers and (ß) alkali metal salts of montan wax _acids , of C ₁₀ to C ₂₀ fatty _alcohol sulfonates and / or C ₁₀ - C _zo alkanesulfonates as dispersants (c) and in the presence of 1 to 15, preferably 5 to 15% by weight, based on (a + b + c), water (e).

Particularly preferred for this preparation of wax compositions containing microcapsules are (c) alkali metal salts of montan wax acids and mixtures of adducts of 15 to 25 mol ethylene oxide with stearyl alcohol, tallow fatty alcohol and / or with partially unsaturated C _1s / C ₁₈ alkanol mixtures and alkali metal salts of montan wax acids.

The amount of water is also based on (a + b + c) - 1 to 15, preferably 5 to 15 wt.%.

This process gives wax compositions which are practically free of microcapsule agglomerates.

• 3.2.1) So kann es z. B. zweckmäßig sein, die wäßrige, das Schutzkolloid enthaltende Phase durch Wasser auszutauschen, indem man die abzentrifugierten Kapseln in Wasser, das gegebenenfalls niedermolekulare Emulgiermittel enthält, anrührt und wieder zentrifugiert und diesen Vorgang 1 bis 3 mal wiederholt.
• 3.2.2) Man kann aber auch so verfahren, daß der Kapseldispersion die später benötigten Mengen an Abstandshaltern (d) und/oder Emulgatoren (c) zugegeben werden und dann die Kapseln durch Sprühtrocknung isoliert werden. Das erhaltene Pulver wird dann in die Wachsschmelze eingearbeitet. Auch die nach 3.2.1 und 3.2.2 erhaltenen Kapseln sind in der Wachsschmelze schwieriger zu dispergieren als die nach 1) oder 2) isolierten Mikrokapseln. Nach dem obenstehenden Verfahren 3.1 erhält man jedoch einwandfreie, praktisch agglomeratfreie Mikrokapseln enthaltende Wachsmassen.
• 3.2.3) Die Dispergierung der trockenen Mikrokapseln im Wachs kann - wenn man als (c) nichtionische Emulgatoren verwendet - verbessert werden, wenn der wäßrigen Mikrokapseldispersion vor der Sprühtrocknung bei 50 bis 100 °C langkettige Fettamine zugegeben werden.
• 3.2.4) Eine weitere Variante besteht darin, der Mikrokapseldispersion vor der Sprühtrocknung Wachs in Form einer Dispersion und gegebenenfalls nichtionische Emulgatoren zuzugeben. In diesem Fall gibt man zu der Mikrokapseldispersion - bezogen auf Mikrokapseln - 15 bis 70, vorzugsweise 25 bis 50 Gew.-% festes Wachs in Form einer Dispersion und 0 bis 10 Gew.-% eines oder mehrerer der für (c) genannten Mittel, vorzugsweise nichtionische Emulgatoren. Solche Dispersionen liefern durch Sprühtrockung ein leicht fließendes Pulver, das in der Wachsschmelze leicht verteilbar ist. Die Kapseln liegen im wesentlichen als Einzelkapseln vor. Die Wachsdispersion soll möglichst fein sein. Die Wachsteilchen sollten zweckmäßigerweise ≤ 10 µm, vorzugsweise _% 2 µm sein.

3.2) The isolation of the microcapsules by spray drying can be varied:

• 3.2.1) So it can e.g. B. be expedient to replace the aqueous phase containing the protective colloid with water by stirring the centrifuged capsules in water, which may contain low molecular weight emulsifiers, and centrifuging again and repeating this process 1 to 3 times.
• 3.2.2) However, the procedure can also be such that the amounts of spacers (d) and / or emulsifiers (c) required later are added to the capsule dispersion and the capsules are then isolated by spray drying. The powder obtained is then incorporated into the wax melt. The capsules obtained according to 3.2.1 and 3.2.2 are also more difficult to disperse in the wax melt than the microcapsules isolated according to 1) or 2). According to process 3.1 above, however, flawless wax compositions containing practically agglomerate-free microcapsules are obtained.
• 3.2.3) The dispersion of the dry microcapsules in the wax - if used as (c) nonionic emulsifiers - can be improved if long-chain fatty amines are added to the aqueous microcapsule dispersion before spray drying at 50 to 100 ° C.
• 3.2.4) Another variant consists in adding wax in the form of a dispersion and, if appropriate, nonionic emulsifiers to the microcapsule dispersion before spray drying. In this case, 15 to 70, preferably 25 to 50% by weight solid wax in the form of a dispersion and 0 to 10% by weight of one or more of the agents mentioned for (c) are added to the microcapsule dispersion, based on microcapsules. preferably nonionic emulsifiers. By spray drying, such dispersions provide an easily flowing powder which is easily dispersible in the wax melt. The capsules are essentially single capsules. The wax dispersion should be as fine as possible. The wax particles should expediently be 10 10 μm, preferably _% 2 μm.

4) The emulsifier and then the aqueous micro become a wax melt capsule dispersion added all at once and the water is distilled off at normal pressure or preferably in vacuo with stirring above the melting temperature of the waxes. Inert gas is advantageously passed through the apparatus. Care must be taken that the wax mass remains liquid, since otherwise mixtures are formed which contain a high proportion of agglomerated microcapsules.

5) The microcapsule dispersion is concentrated with thorough mixing until the residue is in the form of a pasty mass. The concentration can be carried out under normal pressure in vacuo or under pressure, if appropriate with the passage of air or inert gas. To further remove the water, dispersant (c), water-soluble waxes and optionally low-melting or liquid agents are added to the residue, which are required to adjust the viscosity of the wax melt. Such means are e.g. B. Vaseline and mineral oil.

In this way, the water can be largely or almost completely removed, the temperature should not exceed 120 ° C. With this method, the water can be removed more quickly than with the method in which the microcapsule dispersion is added to the wax melt and the water is removed from the wax melt. Foam caused by the presence of (c) can be defoamed, e.g. B. those based on silicone, easily destroyed. A melt of wax and the components still required can then be immediately added to the viscous dispersion thus obtained, a homogeneous melt being formed by stirring and containing the microcapsules in dispersed form. But you can also proceed that one enters the components one after the other and mixes the melt homogeneously. In this case, the solid, non-melting components, e.g. B. pigments and spacers are added last.

If the specified measures are observed, the various processes deliver very homogeneous melts that are ideally suited for the production of pressure-sensitive carbon-free copy papers. The melts obtained in 1) to 5) contain the microcapsules essentially as individual capsules in addition to agglomerates. The proportion of agglomerates is lowest in most cases if there is some water in the melt from the beginning.

The method according to 3.1) is preferred for the industrial production of wax compositions containing microcapsules, since this easily provides wax compositions which are practically free of agglomerates.

The intensity of the copy of the carbonless reaction papers containing wax as a binder is generally somewhat less than that of carbonless paper coated with dispersions containing aqueous microcapsules. This applies in the event that the wax compositions containing the microcapsules are on the paper surface (i.e. practically no wax has penetrated the paper yet). If you work with the coating so that the wax can penetrate the paper, you get intensively copying coatings.

This method of working has proven particularly useful for the production of carbon paper for sets of forms, in which the inscription sheet (carbon paper) carrying the color capsules containing the color formers is removed after writing. This insert sheet is clean compared to the known carbon-based carbon paper. This gives - with the carbon paper coated with the wax composition according to the invention - clean copies on which, after the removal of the insert sheet, no further unwanted copies are produced during further treatment.

The following exemplary embodiments are intended to explain the invention in addition. The parts and percentages given below refer to the weight. The room parts are related to the parts by weight like liters to kilograms.

I. Preparation of the microcapsule dispersion 1.1 Microcapsule dispersions 1 to 4

968 parts of water and 160 parts of a 20% strength solution of poly-2-acrylamido-2-methyl-propanesulfonic acid / sodium salt (viscosity 880 mPas) are mixed in a cylindrically shaped stirring vessel with a built-in dispersant (sturrax from Jahnke and Kunkel) , the mixture heated to 40 ° C and adjusted to pH = 4.0 with formic acid. 800 parts of a solution on 9.3 parts of 3'-phenyl-7-N-dimethylspirodibenzopyran, 22.65 parts of 2,6-diphenyl-4- (4'-dimethylaminophenyl) are then in the aqueous solution at the highest speed of rotation -pyridine, 9.35 parts of 3-dibutylamino-5-diethylamino-2,4-diazarhodamine lactone, 6.13 parts of N-benzoyl leukomethylene blue and 0.40 parts of crystal violet lactone dispersed in 749.53 parts of dodecylbenzene. A solution made up of pH = 4.0 from 120 parts of a partially methylated precondensate which is clearly soluble in water (contains about 2.3 CH ₃ O groups per melamine molecule) of melamine and formaldehyde (ratio 1: 5.25 mol) in 132 parts of water at 40 ° C. while maintaining the pH at 4.0. After about 1.5 hours, the capsule formation can be determined in a sample under the microscope: the emulsion droplets no longer run together on the slide. After 3 h and 10 min, the dispersant is switched off and the microcapsule dispersion formed is cured with stirring (propeller stirrer) at the temperatures and times given in the table. The capsule dispersion is then cooled and adjusted to pH 8 to 9 with ammonia. The dispersion is then sieved through a 40 J.1.m sieve.

The dispersions obtained are colorless, milky and, after measurement in the Coulter Counter TF, contain individual capsules with a most common particle diameter of 5.6 μm. The solids content is 40.0%.

1.2 Microcapsule dispersion 5

The dispersion is prepared as described under 1.1, but a solution of 180 parts of the melamine-formaldehyde precondensate in 200 parts of water (pH = 4.0) is added over the course of 4 hours. The 40% dispersion is post-cured for 2 hours at 95 ° C. and pH 4.0. The dispersion contains individual capsules with a common diameter of 3.4 µm (measured in the COULTER Counter TF).

1.3 Microcapsule dispersion 6

The dispersion is produced according to 1.1, however the post-curing takes place at pH = 4.1 and 70 ° C. Duration: 5 hours. Solids content: 40%; most common diameter of the microcapsules: 5.7 µm.

1.4 Microcapsule dispersion 7

The dispersion is prepared as indicated under 1.1, but a solution of 180 parts of a water-soluble, partially methylated precondensate (contains approx. 5 OCH ₃ groups per melamine molecule) made of melamine and formaldehyde (1: 6 mol) in 200 parts of water added in 4.5 h. Post-curing takes place at pH 4.0 and 70 ° C; Duration: 5 hours. Solids content: 38.9%; most common capsule diameter: 5.4 µm.

1.5 Microcapsule dispersion 8

The dispersion is prepared according to 1.4, but the same amount of a partially methylated precondensate made of melamine-formaldehyde (1: 5.7 mol) with 2.3 CH ₃ 0 groups per melamine molecule is used. Solids content: 38.4%; most common capsule diameter: 5.9 µm.

11. Checking the wax mass

The wax compositions produced were tested as follows.

a) Distribution of the microcapsules:

A drop of the wax melt containing microcapsules is spread on a hot slide and the microcapsules are assessed under the microscope.

b) Staining CF layers b1) Staining by color formers contained in the wax mass due to destruction of microcapsules in the manufacture of the wax mass.

Approx. 1 ml of the melt produced is poured onto the active side of a CF sheet. This position is called «Approach. The wax melt is then quickly pulled out with a card sheet, so that a thin coating that does not penetrate into the paper is created (“layer”). After 24 hours of storage, the sheet is assessed on the "batch and in the" layer "in the coloring.

• Note 1 = farblos
• 2 = schwache Färbung
• 3 = deutliche Färbung
• 4 = gefärbt
• 5 = intensive Färbung.

The assessment is made with grades 1 to 5, mean

• Note 1 = colorless
• 2 = weak coloring
• 3 = clear coloring
• 4 = colored
• 5 = intense coloring.

b2) Staining during the production of copies

• Note 1 = sehr intensive Durchschrift
• 2 = intensive Durchschrift
• 3 = gut lesbare Durchschrift
• 4 = noch lesbare Durchschrift
• 5 = nicht lesbare Durchschrift

The coated paper obtained according to b1) is placed with the coated side on CF paper and copies are made with this set. The copies were rated 1 to 5. Mean:

• Grade 1 = very intensive copy
• 2 = intensive copy
• 3 = easy to read copy
• 4 = still legible copy
• 5 = illegible copy

c) viscosity of the wax melt

The viscosity was determined in a ®Rotovisko from Gebr. Haake, Berlin, with a fluted measuring cylinder and beaker at a shear rate of 428 sec- ¹ and 85 and 95 ° C.

d) determination of the solids content

For this purpose, about 1 g of melted wax was weighed in and the sample was dried at 105 ° C. for 5 hours.

III. Embodiments Examples 1 to 4 Production of the wax compound containing microcapsules

80 parts of a paraffin with a melting point of 52 to 54 ° C. and 40 parts of an ester wax composed of montanic acid and 1,4-butanediol (melting point 80 to 83 ° C.; melting point of the mixture 71 to 78 ° C.) are placed in a heatable stirred tank with anchor stirrer and distillation attachment. melted at 95 ° C. Then 27 parts of petroleum jelly and 21.5 parts of an adduct of 23 moles of ethylene oxide are added to a partially unsaturated C ₁₆ / C ₁₈ alcohol mixture and, after dissolution, 280 parts of the capsule dispersion specified below are added all at once with stirring. A homogeneous dispersion is formed, from which all water is slowly distilled off using a vacuum (up to 200 mm Hg) at a bottom temperature of 90 to 95 ° C (duration: 3 hours). Then the stirred tank is aerated and the melt is poured into a foil trough to solidify.

The following microcapsule dispersions are used:

• a) In den Wachsmassen liegen die Mikrokapseln im wesentlichen als Einzelkapseln vor.
• c) Die Viskosität der Schmelze : ca. 180-190 mPa.s (85 °C) und 160-170 mPa.s (95 °C)
• d) Feststoffgehalt : 92 bis 93 %.

The wax compositions obtained were tested in accordance with II.

• a) The microcapsules are essentially present as individual capsules in the wax compositions.
• c) The viscosity of the melt: approx. 180-190 mPa.s (85 ° C) and 160-170 mPa.s (95 ° C)
• d) Solids content: 92 to 93%.

The results of the tests according to II b) are summarized in Table 1:

The test results show that only those microcapsule dispersions prepared at pH = 4, the capsules of which have been cured at 70 ° C. and above, are suitable for the production of wax compositions by the process of Examples 1 to 4. The assessment of the discolouration of CF paper at the "approach" point is more significant than in the "layer", since capsules are often destroyed when they are brushed on with the edge sheet, which can be recognized by colored lines in the direction of the stroke.

Example 5 5.1 Wax paste containing microcapsules

The microcapsule dispersion 3 (produced according to 1.1) is in a spray dryer (gas inlet temperature rature 120 ° C) to a free-flowing powder (residual moisture: 4%). 112 parts of the powder are introduced into the wax melt from paraffin, ester wax, petroleum jelly and oxethylation product specified in Example 1 and stirred at 90 ° C. for 1 h.

• Ila) die homogene Schmelze enthält etwas mehr Agglomerate als die Schmelzen der Beispiele 1 bis 4.
• IIb1) Es tritt keine Färbung auf der CF-Schicht auf. Note 1 für « Ansatz und « Schicht ».
• Ilc) Viskosität : 350 mPas (85 °C) 260 mPas (95 °C).

Testing the wax mass obtained according to 5.1:

• Ila) the homogeneous melt contains slightly more agglomerates than the melts of Examples 1 to 4.
• IIb1) There is no coloring on the CF layer. Grade 1 for “neck and layer”.
• Ilc) Viscosity: 350 mPas (85 ° C) 260 mPas (95 ° C).

• 5.2) Der Dispersion 3 werden 29 %, bezogen auf Feststoffgehalt, einer kugelförmigen, in Wasser nicht löslichen Stärke als Abstandshalter zugegeben. 93 Teile des Trockengutes (Restfeuchte : 3 %) werden in die Wachsschmelze gegeben.
• 5.3) Der Dispersion 3 werden 80 % des in der Wachsschmelze 5.1) enthaltenen Ethylenoxidadduktes (= 16 %, bezogen auf Mikrokapseln) zugemischt und diese Dispersion getrocknet. Es werden 93 Teile Trockengut (Restfeuchte : 15 %) zu der Wachsschmelze gegeben.
• 5.4) Der Dispersion 3 werden vor dem Trocknen die unter 5.2) angegebene Menge Stärke und die gesamte Menge des in sonst in der Wachsschmelze vorhandenen Ethylenoxidadduktes ( = 20 %, bezogen auf Mikrokapseln) zugegeben. 117 Teile Trockengut (Restfeuchte : 11 %) werden in die Wachsschmelze gegeben.

An equally good result is obtained if the microcapsule dispersion 3 is spray-dried according to the following variants:

• 5.2) 29%, based on the solids content, of a spherical, water-insoluble starch is added to the dispersion 3 as a spacer. 93 parts of the dry material (residual moisture: 3%) are added to the wax melt.
• 5.3) 80% of the ethylene oxide adduct contained in the wax melt 5.1) (= 16%, based on microcapsules) is mixed into the dispersion 3 and this dispersion is dried. 93 parts of dry material (residual moisture: 15%) are added to the wax melt.
• 5.4) Before drying, the amount of starch specified under 5.2) and the total amount of ethylene oxide adduct present in the wax melt (= 20%, based on microcapsules) are added to the dispersion 3. 117 parts of dry material (residual moisture: 11%) are added to the wax melt.

The wax masses obtained according to 5.2), 5.3) and 5.4) do not stain CF paper during the test according to II. B1).

Testing the waxes obtained in accordance with II. B2), II. C) and II. D):

Example 6

6.1) The microcapsule dispersion 5 is centrifuged in a centrifuge for 1/2 h at 600 g. The microcapsules settle on the surface and can be removed as a solid cake (water content: 39%).

6.2) to a 90 ° C melt of 80 parts paraffin (mp 52 to 54 ° C), 40 parts of the ester wax mentioned in Example 1, 27 parts petroleum jelly (white) and 21.5 parts of the ethylene oxide adduct mentioned in Example 1, the 22.4 parts of a free-flowing, granular urea-formaldehyde condensation product (diameter of the grains approx. 1 μm, which form agglomerates of up to 12 μm in diameter), 184 parts of the aqueous cake obtained according to 6.1) are introduced with stirring. After 30 minutes there is a homogeneous melt, the water content of which cannot be seen (water content: 17.8%).

6.3) In the test according to II. B1), no discoloration occurs on the CF layer. There is also no evidence of paper being thrown (despite the water containing the melt). With CB coatings made from this wax mass, easily legible copies are obtained: grade 3 (according to II. B2)).

If, on the other hand, microcapsule dispersion 2 is used instead of microcapsule dispersion 5, a wax mass (residual moisture: 6.4%) is obtained which, in the test according to II. B1), colors the CF layer a strong greenish-gray. Grade 4 («approach and« layer »). The copies obtained with this wax mass are still quite legible (grade 3-4). Viscosity (llc): 186 mPas at 95 ° C.

Example 7

In the apparatus described in Example 1, 28.8 parts of paraffin (mp. 52 to 54 ° C), 14.4 parts of the ester wax specified in Example 1, 4.9 parts of petroleum jelly (white) and 4.8 parts of the ethylene oxide adduct are Example 1 melted at 80 ° C. At this temperature, 62 parts of microcapsule dispersion 6 are added to the homogeneous melt with stirring, and 35 parts of water are distilled off at a bottom temperature between 82 and 73 ° C. while the pressure is slowly falling. As a result of the water evaporating too quickly, the melt must not locally fall below the solidification point, since this can form agglomerates that can no longer be broken up. The wax composition obtained has a viscosity of 139 mPas at 85 ° C and 131 mPas at 95 ° C. Solids content according to II d): 98.2%.

• II b.1) Note 1 « Ansatz
  1-2 im Strich (kaum wahrnehmbare strichförmige graue Striche)
• II b.2) Note 3-4 (Menge : 5 g Wachsmasse/m²)

In the spread on a heated slide, there are predominantly individual capsules with few agglomerates. The test according to II b) revealed

• II b.1) Note 1 «Approach
  1-2 in the line (barely noticeable line-shaped gray lines)
• II b.2) Grade 3-4 (quantity: 5 g wax / m ² )

Example 8

39.1 parts of microcapsule dispersion 7 are mixed with 2.2 parts of the ethylene oxide adduct from Example 1 and 5.95 parts of petroleum jelly (white) with stirring at 90 ° C. and 15.3 parts of water are distilled off from this mixture under reduced pressure. To prevent foam, a small amount of a defoamer (base: silicone) is added.

A 90 ° C. melt of 17.6 parts paraffin (mp. 52 to 54 ° C.), 8.8 parts of the ester wax specified in Example 1 and 1.5 parts of the ethylene oxide adduct specified above are then added to this liquid mixture. The wax melt is dispersed immediately. The mixture is stirred for a further 1.5 hours at 88 ° C. and then drained off. Solids content: 84.4%. Viscosity of the melt at 85 ° C: 574 mPas, at 95 ° C: 485 mPas.

In the test according to II. B1), no coloring is found in either the “batch” or “in the layer”. Note 1.

Examination of the copy according to II. B2) gave the grade 2-3 (coating weight: 6.5 g / m ² ).

Example 9

64 parts of microcapsule dispersion 8 are mixed with 3.23 parts of the ethylene oxide adduct from Example 1 and 5.95 parts of petroleum jelly (white) at 80 ° C. and 33.2 parts of water are distilled off from this mixture under reduced pressure within 4 h (bottom temperature: 50 up to 80 ° C). The residue is heated to 80 ° C and a 90 ° C warm melt of 17.6 parts of paraffin (mp. 52 to 54 ° C), 8.8 parts of the ester wax specified in Example 1 and 1.5 parts of the above Added ethylene oxide adduct and dispersed the mixture at 90 ° C for 2.5 h. Viscosity of the mass at 85 ° C: 120 mPas. Solids content: 93.1%.

• nach II b1) Note 1 ; Ansatz und Schicht : keine Verfärbung feststellbar.
• nach II b2) Note 1 ; sehr gute lesbare, scharfe Durchschrift.

A sample melted and smeared on a slide shows predominantly individual capsules under the microscope. The test according to II. B1) and II, b2) shows:

• according to II b1) grade 1; Neck and layer: no discoloration was noticed.
• according to II b2) grade 1; very good legible, clear copy.

Example 10

86.6 parts of capsule dispersion 8 together with 6.4 parts of the emulsifier according to Example 1 and 0.005 part of a silicone defoamer are placed in a vessel comprising 150 room parts with a propeller stirrer, heated to 90 ° C. and then in the course of 3 hours in a vacuum 37. 9 parts of water removed. A hot melt of 9.8 parts of paraffin (melting point 69-73 ° C.) and 19.6 parts of ester wax according to Example 1 is then run into the template at 90 ° C. with stirring. The melt is dispersed immediately. The kettle is closed and dispersed under vacuum for a further 2 hours, a further 3.3 parts of water being distilled off. A homogeneous melt is obtained which contains 50% capsules, based on solids. The solids content is 82.0%. Viscosity at 85 ° C: 505 mPas; at 95 ° C: 530 mPas. The melt contains individual capsules.

In the test according to II b1), no discoloration is observed in either the “approach” or “in the dash”. Rating: 1. Examination of the copy according to Example II b2) gave a rating of 1-2 (coating weight 5.3 g / _m ² ).

Example 11

552 parts of microcapsule dispersion 8 (from 1.5) are mixed with 43 parts of an adduct of 23 mol EO of partially unsaturated C ₁₆ - / C ₁₈ alcohol mixture and 208 parts of water are drawn off from the mixture at 90 ° C. under reduced pressure in 3.5 h . Then a melt of 98 parts of paraffin (mp. 69-73 ° C.) and 196 parts of the ester wax from Example 1 is slowly added and the mixture is stirred for a further 3 hours at 90 ° C. under reduced pressure. 107 parts of water are still transferred. 46 parts of a spherical starch (special starch K from Amylum) are then slowly introduced into the melt and homogenized for 1 h. A thin melt is formed. Viscosity: 319 mPas (85 ° C); 226 mPas (95 ° C); Solids content: 92.2%.

• nach II b1) wird sowohl beim « Ansatz » als auch « im Strich » keine Verfärbung beobachtet ; Note : 1 ; in der Durchschrift nach II b2) : Note 1-2 (Beschichtung 5,5 g/m²).

Checking the wax mass

• according to II b1), no discoloration is observed in either the “approach” or “in the dash”; Note 1 ; in the copy according to II b2): grade 1-2 (coating 5.5 g / m ² ).

If the coated paper obtained in accordance with II b1) is heated at 120 ° C. (drying cabinet) for 2 h, it occurs no discoloration from developed color formers but from the wax penetrating the paper. The paper treated in this way produces outstandingly intensive copies when tested in accordance with II b2); Note: 1. This sheet can e.g. B. can be used as carbon paper.

Example 12

a) 560 parts of microcapsule dispersion 8 and 23 parts of the emulsifier from Example 11 and 5 drops of a silicone defoamer are mixed and stirred under reduced pressure at 89 ° C. for 1.5 hours, 219 parts of water being distilled off. At 90 ° C., the melt is added to a mixture of 196 parts of montanic acid wax (mp. 80-83 ° C.), 98 parts of paraffin (mp. 69-73 ° C.) and 20 parts of the emulsifier from Example 11, and the resulting mixture Mixture stirred homogeneously for 5 h under reduced pressure. Another 65 parts of water are transferred. The result is a homogeneous, smooth melt that contains individual capsules. Solids content: 85.1%. Viscosity: 412 mPas (85 ° C); 324 mPas (95 ° C).

In the test according to II b1), no coloring was found in either the «approach or« line (grade: 1).

The examination of the intensity of the copy according to II b2) gave the grade 3 (coating: 4.8 g / m ² ).

If the coated paper is stored for 2 hours at 120 ° C., paper soaked with wax is obtained, which gives copies with a grade of 1-2.

b) If, instead of the 196 parts of montanic acid wax, the same amount of bleached montanic acid esterified with ethylene glycol (mp. 77-80 ° C.) is used in a), a homogeneous melt is obtained which contains individual capsules. Solids content: 89.5%. Viscosity: 251 mPas (85 ° C); 307 mPas (95 ° C).

When this mass is tested according to II b1), no discoloration is found in either the "approach or" line; Note 1.

The examination of the intensity of the copy according to II b2) gave the grade 2 (coating: 5.8 g / m ² ). If the paper coated according to II b1) is stored for 2 hours at 105 ° C., a paper soaked in wax is obtained which gives very intensive copies (grade: 1).

Example 13

• a) 801 parts of microcapsule dispersion 8 and 308 parts of an aqueous dispersion, the 16.5% ethylene glycol ester of montanic acid, 10% ozokerite and 4.5% of an emulsifier mixture from the emulsifier and tributylphenol + 4 EO mentioned in Example 11 (ratio 8.5: 1.5) are mixed and the dispersion obtained is dried at an inlet temperature of 120 ° C. in a spray tower (gas outlet temperature: 70 ° C.).
• b) 109 parts of the fine, free-flowing dry material are melted into 24 parts of an ester wax composed of montanic acid and butanediol (mp. 80-83 ° C.), 13 parts of an EO adduct of 23 mol EO onto a partially unsaturated C ₁₆ - / C ₁₈ alcohol mixture and 53 parts of paraffin (mp. 52-54 ° C) entered with stirring and stirred at 90 ° C for 4 h. 15.2 parts of a spherical starch (special starch K from Amylum) are then introduced into the homogeneous melt over the course of 1 h, and the melt is stirred until homogeneous. A homogeneous, smooth melt is obtained. Solids content: 99%. Viscosity at 85 and 95 ° C: 800 mPas. The melt essentially contains individual capsules.

In the test according to II b1), no discoloration is found in either the “approach” or “in the dash; Note 1.

Since the melt was too viscous for an application, the viscosity in a sample was reduced by mixing in 10% petrol and this melt was used to test the copy according to II b2): grade 1-2 (coating 7.2 g / m ² ) .

Practically the same result is achieved if the viscosity of the melt is reduced by emulsifying water (7%).

Example 14

a) 750 parts of microcapsule dispersion 8 are mixed with 385 parts of a dispersion which contains 35% of a montanic acid esterified with ethylene glycol and 5% of an adduct of 23 mol of EO with tallow fatty alcohol, and is dried by spraying (gas inlet temperature 120 ° C., outlet temperature 70 ° C.) .

The diameter of the wax particles in the wax dispersion is well below 1 µm, so that the particles can no longer be seen under the light microscope.

b) 152 parts of the easily flowing dry material are portioned into a 95 ° C warm melt from 53 parts of paraffin (mp. 52-54 ° C) and 4.5 parts of the adduct of 23 mol EO with a partially unsaturated C ₁₆ - / C ₁₈ -Alcohol mixture registered. The melt is stirred for 3 hours. It contains practically no water. The capsules are not agglomerated. Viscosity at 95 ° C:> 800 Pas.

In the test according to II b1), no discoloration is found in either the “approach” or “in the dash”. Note 1.

To test the copy according to II b2), the melt was diluted with 10% petrol. Rating: 1 (coating: _{3, 7} g _{/ m} ^2).

Example 15

The microcapsule dispersion 3 (produced according to 1.1) is dried in a spray dryer (gas inlet temperature: 120 ° C.) to a free-flowing powder. Residual moisture: 4%.

15.1 90 parts of this powder are slowly poured into a melt of 72 parts paraffin (melting point 52 to 54 ° C), 60 parts ester wax from montanic acid and ethylene glycol (melting point 78 to 80 ° C) and 5 parts sodium salt of montan wax acid (acid number 140) entered in the form of a 26.5% aqueous paste and stirred at 90 ° C for 3 h. A paste-like melt is obtained which still contains many capsule agglomerates.

15.2 90 parts of microcapsule powder are introduced as in 15.1 into a melt of 87 parts of paraffin, 60 parts of the ester wax specified in 15.1 and 9 parts of sodium salt of the montan wax acid specified in 15.1 in the form of a 26.5% strength aqueous paste and stirred homogeneously.

A practically smooth melt is obtained which no longer contains any agglomerates. Solids content: 93.4%, viscosity: 121 mPas (85 ° C).

• IIb1) Ansatz : Note 1 ; Schicht : Note 1 bis 2 (kaum wahrnehmbare Striche)
• IIb2) Intensität der Durchschrift: Note 2 bis 3
• 15.3 In der Intensität der Durchschrift vergleichbare Ergebnisse erhält man, wenn man in dem Wachsgemisch von 15.2 anstelle des dort angegebenen Natriumsalzes der Montanwachssäure ein Natriumsalz einer Montanwachssäure mit einer Säurezahl von 120 in Form einer 27,4 %igen wäßrigen Paste anwendet und sonst wie in 15.1 verfährt.

Testing the wax mass according to Ilb):

• IIb1) Approach: grade 1; Layer: grade 1 to 2 (barely noticeable lines)
• IIb2) Intensity of copy: grade 2 to 3
• 15.3 Results comparable to the intensity of the copy are obtained if, in the wax mixture of 15.2, instead of the sodium salt of montan wax acid given there, a sodium salt of montan wax acid with an acid number of 120 in the form of a 27.4% strength aqueous paste is used, and otherwise as in 15.1 moves.

The melt contains individual capsules, as well as some agglomerates. Solids content: 92.8%, viscosity: 130 mPas (85 ° C); 110 mPas (95 ° C).

• IIb1) Ansatz : Note 1 ; Schicht : Note 1 bis 2
• IIb2) Durchschrift: Note 2.

Examination according to Ilb):

• IIb1) Approach: grade 1; Layer: grade 1 to 2
• IIb2) Copy: Note 2.

Example 16

16.1 The procedure is as in Example 15.2, but the wax melt additionally contains 1 part of an ethylene oxide adduct of 23 moles of ethylene oxide with a partially unsaturated C ₁₆ / C ₁₈ alcohol mixture.

16.2 The procedure is as in 16.1, but 3 parts of the ethylene oxide adduct mentioned under 16.1 are used.

After 3 h at 90 ° C., smooth, homogeneous melts are obtained in both cases, which practically contain only individual capsules.

In the case of the coating obtained with the wax composition from Example 16.2, a more intensive copy (grade: 2) is obtained when the coated paper was stored at 80 ° C. for 2 hours.

Example 17

71 parts of the powdery microcapsules obtained according to Example 5.1 are slowly poured into a melt of 72 parts of paraffin (mp. 52 to 54 ° C.), 60 parts of ester wax (from montan wax acid and ethylene glycol), 22.5 parts of a 40% aqueous solution of C. , _5- Paraffin sulfonate / sodium salt (= 9 g dry), 1 part of the ethylene oxide adduct indicated in Example 16.1 and 10 parts of water and stirred in at 90 ° C. for 3 h until homogeneous. The melt contains practically only individual capsules. Solids content: 92.8%; Viscosity: 243 mPas (85 ° C), 150 mPas (95 ° C).

• IIb1) Ansatz : 1 ; Schicht : 1
• IIb2) Durchschrift: 3

Examination according to Ilb):

• IIb1) Approach: 1; Layer: 1
• IIb2) Copy: 3

Example 18

• Feststoffgehalt : 93,1 %
• Viskosität : 307 mPas (85°C) ; 258 mPas (95 °C).
• Prüfung nach Ilb :
  • IIb1) Ansatz : 1 ; Schicht : 1
  • IIb2) Durchschrift : 2 bis 3

In a melt of 72 parts of paraffin (mp. 52 to 54 ° C), 60 parts of ester wax (mp. 78 to 80 ° C, montan wax acid and ethylene glycol), 32 parts of a 28.4% aqueous solution of sodium lauryl sulfate (= 9 parts dry) and 3 parts of the ethylene oxide adduct specified in Example 16.1, 71 parts of microcapsules isolated by spray drying are slowly incorporated and the mixture is stirred homogeneously at 90 ° C. for 3 h. The melt essentially contains individual capsules.

• Solids content: 93.1%
• Viscosity: 307 mPas (85 ° C); 258 mPas (95 ° C).
• Examination according to Ilb:
  • IIb1) Approach: 1; Layer: 1
  • IIb2) Copy: 2 to 3

Claims (7)

1. A microcapsule-containing wax composition which contains - based on (a + b + c) -

a) from 20 to 55 % by weight of microcapsules,

b) from 79 to 30 % by weight of wax, or of a mixture of different waxes, having a melting point of from about 50 to 140 °C,

c) from 1 to 10 % by weight of at least one non-ionic emulsifier, at least one alkali metal salt of a montan wax acid or a mixture of (a) at least one non-ionic emulsifier and (ß) at least one alkali metal salt of a montan wax acid or C_1o-C_2o-fatty alcohol-sulfate and/or C₁₀-C₂₀-alkanesulfonate,

d) from 0 to 20 % by weight of pigments and/or fillers, and

e) from 0 to 60 % by weight of volatile constituents, with or without

f) other agents usually used in such wax compositions, the wall material of the microcapsules (a) being a polymeric melamine-formaldehyde condensate which is obtained by condensing melamine with formaldehyde or condensing methylol-melamines and/or their methyl ethers, using a ratio of melamine to formaldehyde of from 1 : 2 to 1 : 6, at a pH of from 3.5 to 5.5 and at from 60 to 100 °C, and then hardening for from 2 to 10 hours at from 60 to 100 °C, the ratio of core material to wall material in the capsules being from 1 : 15 to 1 : 2 and the microcapsules having a diameter of from 2 to 10 µm.

2. A wax composition as claimed in claim 1, wherein (c) consists of at least one alkali metal salt of a montan wax acid or a mixture of at least one alkali metal salt of a montan wax acid and at least one reaction product of from 13 to 30 moles of ethylene oxide with one mole of stearyl alcohol, tallow alcohol and/or a partially unsaturated C₁₆-C₁₈-alkanol mixture.

3. A wax composition as claimed in claim 1 or 2, which contains from 3 to 10 % by weight, based on (a + b + c), of (c).

4. A process for the production of a microcapsulecontaining wax composition as claimed in claim 1 by mixing the components in the wax melt, wherein there are used as (a) microcapsules which have been obtained by spray-drying an aqueous microcapsule dispersion containing - based on the microcapsules - 15 to 70 % by weight of solid wax in the form of an aqueous dispersion, and 0 to 10 % by weight of at least one non-ionic emulsifier, at least one alkali metal salt of a montan wax acid or a mixture of (a) at least one non-ionic emulsifier and (β) an alkali metal salt of a montan wax acid, a C₁₀-C₂₀-fatty alcohol-sulfate and/or a C₁₀-C₂₀-alkanesulfonate.

5. A process for the production of a microcapsulecontaining wax composition as claimed in claim 1 by mixing the components in the melt, wherein the microcapsules (a) isolated by spray-drying are homogenized in a melt of (b) and an alkali metal salt of a montan wax acid or a mixture of (a) a non-ionic emulsifier and (ß) an alkali metal salt of montan wax acid, a C₁₀-C₂₀-fatty alcohol-sulfate and/or a C_lo-C_2o-alkanesulfonate as (c), and in the presence of from 1 to 15 % by weight, based on (a + b + c), of water.

6. A process for the production of a microcapsule-containing wax composition as claimed in claim 2 by mixing the components in the melt, wherein the microcapsules (a) isolated by spray-drying are homogenized in a melt of (b) and an alkali metal salt of a montan wax acid or a mixture of an alkali metal salt of a montan wax acid and a reaction product of from 13 to 30 moles of ethylene oxide with one mole of stearyl alcohol, tallow alcohol and/or a partially unsaturated C₁₆-C₁₈-alkanol mixture as (c), in the presence of from 1 to 15 % by weight, based on (a + b + c), of water.

7. The use of a microcapsule-containing wax composition as claimed in claim 1, 2 or 3 for the production of carbonless copy paper or microcapsule-coated copy paper.