JPH0375215B2 - - Google Patents

Description

[Detailed description of the invention]

Microcapsules are prepared by dispersing the substance to be encapsulated (core material) and an aqueous solution of polyisocyanates in a hydrophobic solvent, adding a polyamine that is soluble therein to a continuous aqueous phase;
and by forming polyurea at the interface of dispersed droplets of polyisocyanate and polyamine. This method of microencapsulation by interfacial polyaddition is only applicable if the core material is inert towards polyisocyanates and if water-insoluble polyamines are used. It cannot be used to encapsulate substances that react with polyisocyanates, such as polyamines themselves. Water-insoluble polyamines are also not suitable for this process. The present invention relates to microcapsules consisting of capsule walls produced by the reaction of hydrophobic and water-soluble polyisocyanate adducts with water-insoluble polyamines. The present invention also includes emulsifying a hydrophobic core material and water-insoluble polyamines in water or an aqueous solution of a protective colloid, adding bisulfite adducts of water-soluble polyisocyanates in the form of a powder or an aqueous solution, and 1 to 140
It also relates to a process for producing microcapsules, characterized in that the reaction is carried out to completion at a temperature of .degree. The core material according to the invention can consist solely of the wall-forming polyamine or can additionally contain solvents or active substances or both. If the core material consists exclusively of polyamines, a portion of the polyamines is used to form the walls of the capsules, so that the capsules also contain polyamines. If the core material contains a solvent and/or an active substance in addition to the polyamine, the polyamine is used completely for the production of the capsule wall, so that the capsule contains the active substance, the solvent or both. There is. Depending on their contents, the microcapsules can be used, for example, as dye-precursor-containing microcapsules in sensitive copying papers, as microcapsules containing flame retardants or blowing agents or catalysts in the production of polymers, or Activated carbon-containing microcapsules for use as solvent-containing microcapsules in the reactivation of adhesives and also as dye- or pigment-containing microcapsules as toning agents in reproduction systems, as well as for use in all types of absorption systems. Can be used as capsules. The diameter of the capsule is 0.2~2000μm or more, preferably
Can be up to 2000 μm. When the capsules are used as dye-precursor-containing microcapsules in sensitive copying papers, a capsule distribution with a median value of 3 to 10 μm is preferred. If relatively small capsules are present in the form of clumps or clusters, a corresponding distribution of clumps with a median diameter of 3 to 10 μm is preferred. In the case of encapsulation of catalysts, the reaction components are as follows:
The median capsule diameter is preferably between 3 and 20 μm;
The reason for this is, for example, that only with diameters distributed over this range a sufficiently homogeneous dispersion of active substances in the capsules can be reacted completely. For special applications, especially when the active powders have to be released over large areas or all of them by mechanical breaking of the capsules, e.g. during extrusion or mixing under high shear forces or e.g. In the case of a dried activatable adhesive phase containing a microencapsulated solvent such that the adhesive is dissolved and activated by disruption of the capsule wall by the application of pressure,
It is advantageous to use relatively large capsules. For such systems, capsule diameters of 100 to 1000 μm are suitable, with capsule diameters of 300 to 500 μm being particularly preferred. The wall percentage of the active substance-containing microcapsules can vary widely. Depending on the intended use, for example if the capsules are required to be particularly impermeable or if the mixture containing microcapsules for the production of molded articles is required to exhibit a high storage stability, A relatively high percentage of the capsule is due to the wall. On the other hand, if the pressure required for complete release of the contents of the capsule upon mechanical rupture of the capsule cannot or must not be exceeded, a relatively small percentage of the capsule is due to the walls. It is configured. An increase in capsule stability is observed as the percentage of the capsule constituted by the wall increases between 9 and 50%. Although it is in principle possible for a relatively high percentage of the capsule to be constituted by the wall, this is generally undesirable. Microcapsules according to the invention are prepared by emulsifying a mixture of water-insoluble substances and water-insoluble polyamines in water and/or optionally in an aqueous protective colloid solution to the required particle size, The sulfite adduct is added in the form of a powder or an aqueous solution, and the reaction is then carried out for 1
It is produced by carrying out at a temperature of ~140°C. The protective colloid is present in a small amount in the aqueous phase, preferably 0.01
It is present in a concentration of ~2% by weight, more particularly 0.25% by weight. Other thickening agents that act as stabilizers against precipitation can also optionally be present in the same amount as the protective colloid. However, it is pointed out in this regard that thickening agents act as stabilizers against protective colloids and precipitation, which prevent the droplets from re-coallocating during emulsification and from solidifying the microcapsules formed. , cannot be unambiguously defined with respect to their scope of action. Although protective colloids always exhibit some degree of precipitation-stabilizing effect, thickening agents often also exhibit a pronounced protective colloid effect. Suitable protective colloids are, for example, polyvinyl alcohol, carboxymethylcellulose and gum arabic. Suitable thickening agents are, for example, alginates and xanthans. The oil phase of the oil-in-water emulsion is between 0.5 and 50% by weight, preferably between 15 and 45%, more preferably between 30 and 40%. Emulsions are prepared by adding the water-insoluble substance and the polyamine or polyamine mixture in liquid or molten form to a receiving medium, which may optionally be heated, with stirring. If the mixture of water-insoluble substances and polyamine has a melting point above room temperature, the emulsification step can be carried out by a preceding step, e.g. by spraying or milling from the melt, and a dispersion step in which the finely divided substance is dispersed in the aqueous receiving medium. It can be divided into stages. To produce the capsule wall, the reactive polyamine must be heated to its melting point. Emulsification can be carried out using common commercial equipment, such as laboratory stirrers, propeller stirrers or mixing devices operating on the rotor-stator principle, such as mixing sirens. For emulsification with sufficient internal mixing, very strong shearing effects are not necessary. Typical of the amines according to the invention are those which are very easily emulsifiable even in mixtures with other water-insoluble substances. In small containers, vigorous shaking is often sufficient to produce an emulsion (surfactant effect of water-insoluble amines). When the bisulfite adducts of polyisocyanates are added in the form of an aqueous solution, their concentration is generally from 0.5 to 80% by weight, preferably from 10 to 60% by weight,
More preferably, it is 20 to 45% by weight. The oil phase of the emulsion must contain at least the amount of polyamine required for encapsulation.
Bisulfite adducts based on polyamines are created by combining polyamines with shielded polysulfite adducts, predicting that the NH ₂ -groups of the amine will react with the (capped) NCO- groups of the polyisocyanate in a 1:1 molar ratio. It is added in such an amount that the required wall component is obtained from reaction with the isocyanate. If the polyamine is completely reacted, the bisulfite adduct must be used in corresponding stoichiometric amounts. To promote complete reaction of the amine, the bisulfite adduct should be added in 5 to 50% less than the stoichiometric amount.
It is recommended to use 20% more by weight. If a portion of the polyamine remains in the capsule core, the required percentage of wall component should be taken into account and a correspondingly smaller amount of bisulfite adduct should be used. Preferred wall component percentages are from 5 to 64% by weight, preferably from 8 to 40%, more preferably from 10 to 12%.
% by weight. The reaction of the components to produce the capsule wall takes place at temperatures between 1 and 140°C. For bisulfite adducts of aromatic polyisocyanates, temperatures of 1 to 100°C are preferred;
Temperatures of ˜40° C. are particularly suitable. For bisulfite adducts of aliphatic polyisocyanates, temperatures between 50 and 140°C are preferred;
Temperatures of ~98°C are particularly preferred. A very rapid and instantaneous (in the absence of amine) re-decomposition of the bisulfite adducts occurs, accompanied by an increase in temperature. If the solution of bisulfite adducts is heated before mixing with the polyamine emulsion, the solution must be at elevated temperature for only a limited period of time. The table shows the time and temperature at which about 5% of the two bisulfite adducts are re-decomposed.

Table: The polyamines used for the production of capsule walls are insoluble in water. In the concept of the invention, water-
Insoluble polyamines are 2% or less, preferably 1%
The following are to be understood as polyamines which are only soluble in the aqueous phase. Polyamines are to be understood as amines containing at least two primary amino groups. Polyamines having a melting point above room temperature are dissolved, optionally at elevated temperatures, in the water-insoluble material to be encapsulated or heated to a common melting point. If the dissolution or melting temperature is near or above the boiling temperature of water, emulsification should occur in heated water above the common dissolution or melting temperature, optionally under excess pressure. Diamines are preferably used as polyamines. Aliphatic diamines suitable for use according to the invention are, for example, 1,11-undecamethylene diamine, 1,12-dodecamethylene diamine and mixtures and isomers thereof, perhydro-2,4 '- and -4,4'-diaminodiphenylmethane, p-xylene diamine, diamino-perhydro-anthracecenes (DE 2638731). According to the invention, it is also possible to use acid dihydrazides, such as the dihydrazides of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, β-methyladipic acid, sebacic acid and terephthalic acid. Examples of aromatic diamines are given in the German publication specification
2040644 and 2160590, 3,5- and 2,4-diaminobenzoic acid esters according to DE 2025900, DE 1803635 (U.S. Pat.
3681290 and 3736350), 2040650 and 2160589
Ester group-containing diamines described in German published specifications 1770525 and 1809172 (U.S. Pat.
3654364 and 3763295), 2-halogen-1,3-phenylenediamines optionally substituted in the 5-position (DE 2001722, 2025896 and
2065869), 3,3'-dichloro-4,4'-diaminophenyl-methane, 4,4'-diaminodiphenyl-methane, 4,4'-diaminodiphenyl-disulfides (German publication specification 2404976) , diaminodiphenyl dithioethers, (German Publication No. 2509404), aromatic diamines substituted with alkylthio groups (German Publication No. 2638760)
and water-insoluble high melting point diamines described in German Published Specification No. 2635400. Ethylene glycol bis-(p-aminobenzoic acid ester), 2,2'-diaminoazobenzene, 3,3'-
Diaminoazobenzene, 4,4'-diaminoazobenzene, 2,3-diaminobenzoic acid, 2,5-diaminobenzoic acid, 2,2'-diaminoazobenzophenone, 4,4'-diaminobenzophenone, 4,
4'-diaminostilbene, 2,2'-diaminostilbene, 4,4'-diaminotrifhenylmethane,
1,5-naphthylene diamine, 2,6-naphthylene diamine, 2,7-naphthylene diamine, 1,
2-diaminoanthraquinone, 1,5-diaminoanthraquinone, 1,4-diaminoanthraquinone, 2,6-diaminoanthraquinone, 3,6-
Diaminoacridone, 4,5-diaminoacenaphthene, 4,4'-diaminodiphenyl ether,
3,3'-diaminodiphenyl sulfone, 3,3'-
Dimethoxy-benzidine, 4,4'-diaminodiphenylsulfone, 2,3-diaminofluorin,
2,5-diaminofluorin, 2,7-diaminofluorin, 9,10-diaminophenanthrene,
3,6-diaminodiurol, p-xylylene-
bis-(o-aminothiophenyl)-ether,
4,3'-diamino-4'-chlorobenzanilide,
4,2'-diamino-4'-chlorobenzanilide,
4-Chloro-3,5-diaminobenzoic acid ethyl ester, 4-chloro-3-aminobenzoic acid-(4
-chloro-3-aminophenyl ester), 4-
Chloro-3-aminobenzoic acid-(3-chloro-4
-aminophenyl ester), 4-aminobenzoic acid-(3-chloro-4-aminophenyl ester), succinic acid di-(3-chloro-4-amino)-phenyl ester, ethylene glycol bis-
(4-chloro-3-amino)-benzoic acid ester,
3,3'-dichloro-4,4'-diaminodiphenyl carbonate, 4,4'-dichloro-3,3'-diaminodiphenyl carbonate, 4-methyl-3,
5-diaminobenzoic acid methyl ester, 3,5-
Diaminobenzoic acid methyl ester and 4,4'-
Diaminodiphenyl-methane-3,3'-dicarboxylic acid dimethyl ester. Examples of aliphatic diamines are from the German published specification
Aminoalkylthioanilines according to 2734574. The following are other diamines which are particularly suitable for the purposes of the present invention: Aliphatic diamines trans, trans-4,4'-diaminodicyclohexyl-methane, diamino-methylated cyclododecane, bis- (6-amino-n-hexylcarbamic acid)-dipropylene glycol diester. Aromatic diamines diethyltolylenediamine, 3,5-diethyl-3',5'-diisopropyl-4,4'-diaminodiphenyl-methane, 3,3',5,5'-tetraisopropyl, -4, 4'-diaminodiphenyl-methane, 3,3',5,5'-tetraethyl-4,4'-diaminodiphenyl-methane and mixtures thereof, diphenylmethane-3,3'-dithiomethyl-
4,4'-diamine, 3,3'-carboxyethyl-
4,4'diaminodiphenylmethane, dichlorinated 1,3-phenylenediamines, triisopropylated 1,3-phenylenediamine,
3,5-diamino-4-chlorobenzoic acid isobutyl ester, 3,5-diamino-4-methylbenzoic acid isobutyl ester, bis-(4-aminobenzoic acid)-1,3-propanediol diester,
Bis-(4-aminobenzoic acid)-1,3-(2-ethyl)-propanediol diester, and naphthylene-1,5-diamine. In addition to polyamines, the core materials used are also water-based.
It is insoluble and exhibits insolubility with respect to polyamines in water. The core materials to be encapsulated must be inert towards primary amino groups. The wall-forming polyamine must be miscible with the core material when it is in liquid or melt form. The polyamine itself can also form part of the capsule interior together with other core materials. Furthermore, finely dispersed solids can also be present in the dispersion in the capsule core. The following water-insoluble substances can be used: various water-miscible solvents that dissolve dye precursors suitable for copy paper applications. Examples of these are chlorinated diphenyls, dodecylbenzene, mixtures of partially hydrogenated and unhydrogenated terphenylenes, isopropyl diphenyl, diisopropylbenzene, benzoic acid ethyl esters, diphenyl and diphenyl Mixtures of ethers, phthalic acid dibutyl esters, aralkyl or diaryl ethers, xylenes or common commercial mixtures of aromatics of the type that accumulate in aromatization plants of the petrochemical and petroleum industries, and Chlorinated paraffins, cottonseed oil,
They are bed bean oil, silicone oil, tricresyl phosphate, monochlorobenzene, alkylated diphenyls, alkylated naphthalenes, and relatively highly alkylated benzenes. Diluents such as kerosene, n-paraffins and isoparaffins are often added. Diluents can be encapsulated separately or in admixture with the solvents described above. A solution of the dye precursor in the abovementioned solvent, the so-called color-
The production solution can be advantageously encapsulated in the manner described above. Examples of dye-precursors are triphenylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds and spiropyran compounds. Particularly suitable dye-precursors are the triphenylmethane compounds: 3,3-bis-(p-dimethylaminophenyl)-6-dimethylaminophthalide and 3,3-bis-(p-dimethylaminophthalide). phenyl)-phthalide (“malachite green lactone”); diphenylmethane compounds: 4,4′-
Bis-dimethylaminobenzhydryl-benzyl ether, N-halogen phenylleucolamine, N-β-naphthylleucolamine, N-
2,4,5-trichlorophenylleucolamine, N-2,4-dichlorophenylleucolamine; Xanthene compounds: rhodamine-β-anilinolactam, rhodamine-β-(p-nitroaniline)-lactam , rhodamine-β-(p-chloroaniline)-lactam, 7-dimethylamino-2-methoxy-fluorane, 7-diethylamino-3-methoxy-fluorane, 7-diethylamino-3-methyl-fluorane, 7-diethylamino-3 -chloro-fluoran, 7-diethylamino-3-chloro-2-methyl-fluoran, 7
-diethylamino-2,4-dimethyl-fluorane, 7-diethylamino-2,3-dimethyl-fluorane, 7-diethylamino-(3-acetylmethylamino)-fluorane, 7-diethylamino-3-methyl-fluorane, 3,7 -diethylamino-fluoran, 7-diethylamino-(dibenzylamino)-fluoran, 7-diethylamino-3-(methylbenzylamino)-fluoran, 7-diethylamino-3-(chloroethylmethylamino)-fluorane, 7-diethylamino- 3-(dichloroethylamino)-fluorane, 7
-Diethylamino-3-(diethylamino)-fluoran; Triazine compounds: N-benzoylleucomethylene blue, o-chlorobenzoylleucomethylene blue, p-nitrobenzoylleucomethylene blue; Spiro compounds: 3-methyl-
2,2'-spiro-bis(benzo(f)-chromene)
It is. Low-boiling liquids of a type suitable for use as blowing agents, such as methylene chloride, chloroform or "Frigen", water-insoluble alcohols, water-insoluble catalysts, especially secondary or tertiary containing amino groups, water-insoluble inert reactive polyamines, water bound in water-insoluble hydrates of the type formed by a number of water-insoluble polyamines; Liquid or molten polyamines and/or finely divided solids dispersed in a solvent can also be encapsulated. Such solids include water-insoluble minerals, metal oxides or metals, such as quartz,
Chiyoke, bauxite, iron oxide, nickel,
It can be copper, inorganic pigments, or other organic solids, such as activated carbon or organic pigments.
Polyamines used for the production of capsule walls can also be used as substances to be encapsulated. In this case, generally 5 to 64% by weight, preferably 8 to 40% by weight, of polyamine is used for producing the capsule wall, the remainder remaining as capsule fill. Before emulsifying in the aqueous phase, the substance to be encapsulated is mixed with the polyamine in a customary manner and then emulsified together in the aqueous phase. The percentage of polyamine in the dispersion phase before forming the capsule wall is generally from 1 to 95, preferably from 3 to 50, more preferably from 5 to 13, by weight. The bisulfite adducts used are soluble in water, in other words they are 0.5 to 80
g of bisulfite adduct, preferably from 20 to 40 g. Polyisocyanates are aliphatic or aromatic and contain at least two isocyanate groups. A variety of known aliphatic and aromatic polyisocyanates can be used as bisulfite adducts, provided they are sufficiently soluble in water. In addition to the pure products, it is also possible to use mixtures of bisulfite adducts of various isocyanates and bisulfite adducts of polyisocyanate mixtures. The polyisocyanates in the mixtures can contain varying numbers of isocyanate groups, with difunctional and trifunctional molecules being typical. Bisulfite adducts of aliphatic polyisocyanates are used in aqueous solution or powder form, while bisulfite adducts of aromatic polyisocyanates are dissolved in a slurry immediately before microcapsule production. It is preferred to produce a powder that in general,
The cation chosen for the bisulfite adduct is not critical; sodium, potassium and ammonium ions are common. The bisulfite adduct selected for the lowest solubility in water is
The adducts with the best solubility in water are generally the sodium salts. Suitable water-soluble bisulfite adducts are easily obtained bisulfite adducts of aliphatic polyisocyanates. They can be used in powder form or in aqueous solution. Re-decomposition of bisulfite adducts with aliphatic polyisocyanates occurs to a considerable extent at high temperatures.
Heating the slurry to 50-90°C considerably accelerates capsule formation. Generally, stable microcapsules form within a sufficiently short time at such temperatures. For microencapsulation on an industrial scale, especially if it is carried out continuously, it is preferred to carry out under excess pressure and at temperatures above 100° C. in order to accelerate the encapsulation process. Bisulfite adducts of aromatic polyisocyanates can also be used. The reaction generally does not require high temperatures, as capsule formation occurs sufficiently quickly at temperatures as low as room temperature. At very high temperatures, capsule formation can even become impossible due to agglomeration of the microcapsules or due to precipitation of the polyurethaneurea outside the capsule walls. Bisulfite adducts of aromatic polyisocyanates do not have the same stability in water as those of aliphatic polyisocyanates. At temperatures above room temperature, re-decomposition to bisulfite and polyisocyanate occurs very rapidly as the temperature increases, with conversion of the isocyanate groups corresponding to reaction with water to form polyuritanureas. Such adducts are therefore preferably added to the slurry in dry powder form immediately prior to reaction. Although bisulfite adducts of aromatic polyisocyanates have significant advantages with respect to wall-forming temperatures for microencapsulation, they are less preferred than those of aliphatic polyisocyanates. The reason for this is the poor process safety during microencapsulation and the difficulty of producing this group of adducts on a commercial scale. The following aromatic or aliphatic polyisocyanates which are soluble in water in the form of their bisulfite adducts may be mentioned by way of example:
Chemie, 562, pages 75-136, aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, such as those of the general formula Q(NCO)n [wherein , 2 is 2 to 4, preferably 2, and Q is an aliphatic hydrocarbon group having 2 to 18 carbon atoms, preferably 6 to 10 carbon atoms, and Q is an aliphatic hydrocarbon group having 4 to 15 carbon atoms, preferably 5-10 alicyclic hydrocarbon group, carbon number 6
~15, preferably 6 to 13 aromatic hydrocarbon groups, or 8 to 15 carbon atoms, preferably 8 to 13 carbon atoms
13, representing an aromatic aliphatic hydrocarbon group], such as ethylene diisocyanate, 1,4-tetramethylene diisocyanate,
1,6-hexamethylene diisocyanate, 1,
12-Dodecane diisocyanate, cyclobutane-
1,3-diisocyanate, cyclohexane
1,3- and -1,4-diisocyanates and mixtures of their isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (German published specification
1220785, U.S. Patent 3401190), 2,4- and 2,
6-hexahydrotolylene diisocyanate and mixtures of these isomers, hexahydro-
1,3- and/or -1,4-phenylene diisocyanate, perhydro-2,4'- and/
or -4,4'-diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate, and mixtures of these isomers, diphenylmethane- 2,4'- and/or -4,4'-diisocyanate and naphthylene-1,5-diisocyanate. According to the invention, for example triphenylmethane-
4,4′,4″-triisocyanates, e.g. polyphenyl-polymethylene polyisocyanates of the type obtained by phosgenation of aniline/formaldehyde condensates as described in British Patents 874430 and 848671, m according to US Pat. No. 3,454,606 −
and p-isocyanato-phenylsulfonyl isocyanates, e.g.
Perchlorinated aryl polyisocyanates of the type described in US Pat. No. 1157601 (US Pat. No. 3,277,138), norbornane diisocyanates according to US Pat. Polyisocyanates containing allophanate groups of the type, e.g.
3001973, German patents 1022789, 1222067 and
1027394 and German publication specification 1929034 and
2004048, polyisocyanates containing urethane groups of the type described in Belgian patent 752261 or US patents 3394164 and 3644457, german patent
Polyisocyanates containing acylated urea groups according to 1230778, e.g.
3124605, 3201372 and 3124605 and polyisocyanates containing biuret groups of the type described in Belgian patent 889050. Mixtures of the polyisocyanates mentioned above can also be used. Particularly suitable polyisocyanates are 1,6-
Hexamethylene diisocyanate, 1-isocyanato 3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 2,4- and 2,6
- tolylene diisocyanate, diphenylmethane-2,4'- and/or -4,4'-diisocyanate and urethane, allophanate, isocyanurate, urea or biuret groups and/or
Or polyisocyanates containing an oxadiazinetrione group derived from the above diisocyanates. Bisulfite adducts of aliphatic polyisocyanates are completely stable in water, but are converted to polyureas by reaction with primary amino groups. The reaction occurs at the interface between the outer aqueous phase and the dispersed amine phase. The polyisocyanate is added into the capsule wall by polymer formation at the interface, while the bisulfite remains in the aqueous phase. Bisulfite adducts of polyisocyanates,
Thus, reaction products of sodium bisulfite with aliphatic and aromatic polyisocyanates are known and are described, for example, in S. Petersen, Liebig's Annalen der Chemie,
Volume 562 (1949), pages 205 et seq. Their reaction with amines to produce polyureas is also known. Nevertheless, it was very surprising and unexpected for those skilled in the art that the above microencapsulation process could be carried out so easily. The reason is that experts in the art did not foresee that bisulfite adducts of polyisocyanates would react with water during re-decomposition in view of the very fine dispersion of molecules in aqueous solution. be. In the case of bisulfite adducts of aromatic polyisocyanates, this latter reaction is known as instantaneous re-decomposition at room temperature. Furthermore, experts in the art have determined that the minimum solubility of polyamines in water (2.3 ppm) is sufficient to decompose finely dispersed bisulfite adducts in solution, so that It was predicted that polyurethaneurea would be produced by precipitation of . This prediction was first made in practice using conventionally produced bisulfite; either capsules would not form as in the present invention, or after initial formation they would agglomerate in the slurry upon stirring and the slurry This was confirmed by tests carried out in a range that resulted in gelation to a considerable extent. In no case were capsules able to be isolated, for example by spray drying. This was achieved by producing bisulfite powders that have undergone a specific purification process, as all aqueous solutions of bisulfite adducts used to date contain small amounts of emulsifiers from the manufacturing process. Only when it comes to appendages. After removal of the emulsifier, microcapsules can be produced in the method according to the invention even using aqueous solutions. Aqueous solutions of bisulfite adducts still contain bisulfite from the manufacturing process. These bisulfite residues can be converted to neutral salts by addition of appropriate amounts of neutralizing substances, such as hydroxides, carbonates and/or bicarbonates, before the encapsulation step. suitable. The method for producing the capsule wall can be modified by other means, such as by adding catalysts that promote the re-decomposition of bisulfite adducts, such as triethylenediamine and diethanolamine, or by adding a suitable amount of freshly produced acid bisulfite. This can be accelerated by conversion to neutral salts by addition of hydroxides, carbonates and/or bicarbonates. The amount added must be measured very carefully depending on the progress of the formation of the capsule wall. If the addition is done all at once or in excess, more polyisocyanate than can be reacted directly with the polyamine is easily released, resulting in a more or less noticeable lump. If a recracking catalyst, such as diethanolamine, is added to the oil phase before emulsification, it always acts near the interface during the passage from the dispersed phase to the outer phase. Agglomeration is therefore avoided. The encapsulation method and the resulting microcapsules according to the invention have a number of advantages. Due to its scope of application, more suitable or less expensive elements can often be selected in the method according to the invention. Therefore, when microencapsulation is carried out using high melting point polyamines, it is preferred to use mixtures of polyamines. Generally, polyamines that are liquid at room temperature will dissolve solid, relatively high melting point amines so that encapsulation can be performed at relatively low temperatures. This has the effect of reducing technical simplification, particularly when eg encapsulation under overpressure is avoided in this way. The microcapsules produced by the above method are used in the form of a dispersion in water, but they can also be made into a powder by spray-drying. This is done using conventional industrial equipment and does not require special measures. In addition to the solid component of protective colloids, the powder obtained by spray drying also contains decomposed bisulfites or salts prepared therefrom by further reaction. The amount of salt produced depends on the wall thickness to be adjusted, but can be as much as 20% of the dry substance. Generally, the presence of salts is not a problem. However, in some cases salts must be removed from the spray-dried product, ie, the powder. Since the salt crystals that accumulate during spray drying are considerably smaller than the microcapsules, their removal can be easily carried out during the spray drying process, for example by correspondingly designing and arranging the cyclone and the subsequent tube filter. The microcapsules according to the invention can be used, for example, in the following fields: As dye-precursor-containing capsules for the production of sensitive copying papers; as encapsulated flame retardants, e.g. based on organophosphorus or chlorine and bromine compounds. or in the form of blowing agents or in the form of catalysts containing encapsulated secondary or tertiary amino groups, in the production of molded articles from resins, elastomers, foams. as solvent capsules in the reactivation of adhesive layers; as dye- or pigment-containing capsules used in powder form as toning agents for copying systems; for example for addition into protective fabrics or dialysis. As activated carbon-containing capsules for all types of absorption systems such as systems. If the capsules contain only polyamines, they can be used as slow-acting cross-linking agents for polyurethane systems. The invention is illustrated by the following examples. All percentages and parts shown are by weight. Reverse Encapsulation Example 1 (a) Preparation of Protective Colloid Solution One part polyvinyl alcohol (Mowiol)
26/88, a product of Hoechst AG, Frankfurt), 2 parts of xanthan (Kelzan D, a product of Kelzan D, Baltimore Aircoil/Chemviron SA) and 397 parts of distilled water by stirring at room temperature. Manufactured. (b) Preparation of color-generating agent solution 46 parts of benzoylleucomethylene blue and 139 parts of crystal violet lactone were added.
It was dissolved in 3932 parts of diisopropylnaphthalene by heating and stirring and added to a solution based on 983 parts of isohexadecane. (c) Preparation of color-generating agent solution 1 part green-color-propagating fluorane derivative (Pergascript Olive IG, a product of Ciba Geigy)
was dissolved in 19 parts of diisopropyldiphenyl by stirring and heating to 80°C. Example 2 270 g of the protective colloid solution corresponding to Example 1(a) are added at room temperature into a glass beaker (Kotov type, product of the Kotov Company, Rodenkirchen/Cologne), followed by stirring.
at 950r.pm using MS1FCAB mixed siren)
At room temperature 55 g of the color-former solution of Example 1(b) and 9.5 g of diphenyltolylene diamine were added. The rotation speed was then increased to 9000 rpm for 45 seconds. A very fine oil-in-water emulsion was produced. The rotation speed was reduced to 950 rpm for 15 seconds and then 200 g of a clear solution (temperature 20 DEG C.) consisting of 180 g of protective colloid solution and 20 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate were added. After a second emulsification step lasting 45 seconds with a mixing siren rotating at 9000 rpm, the slurry was transferred to a beaker with a reflux condenser and a laboratory stirrer and heated to 90 °C for a total of 450 minutes. The mixture was stirred at 200 rpm for 20 minutes. A lump-free slurry containing smooth, round and clearly transparent capsules with diameters ranging from 1 to 16 μm was obtained. Spray drying using a laboratory spray dryer (Buchi 190 Mini Spray Dryer, product of Buchi Company, Frauil, Switzerland CH-9230) gave a white, virtually lump-free capsule powder. The capsules had the same range of diameter and liquid core as the slurry. Example 2(a) To produce a carbon-free copying set, the slurry produced according to Example 2 was knife-coated onto type paper sheets in a layer thickness of 20 .mu.m.
After drying the aqueous component of the slurry in air at room temperature, a CB (coated back) sheet (feed sheet) is obtained, the coated back of which is a common commercially available CF (coated back) sheet. The clay-coated surface of the sheet (receiver sheet) was placed so that it was on the surface side that was coated with clay. When writing on the top of the CB-sheet with a ballpoint pen, the capsule of the CB-layer ruptures, the color-former solution is released, and the dissolved dye-precursor reacts in the CF-sheet to form a deep blue color. produced a dye. A corresponding dark blue copy was obtained on top of the receiver sheet. Example 3(a) The process was as in Example 2. Additionally, 15 g of 30% NaOH solution was added 5 minutes after the start of the test. Thereafter, capsule formation occurred very quickly (ie within 10 minutes) with Example 2, but with a pronounced tendency to agglomerate the capsules. Total 60
The test was terminated after 1 minute. The resulting slurry contained almost completely agglomerated capsules. Most of the agglomerates were broken into individual capsules. The individual capsules had a diameter of 1-15 μm and a wrinkled surface, and were non-spherical and opaque. Example 3(b) The process was as in Example 2. Additionally, 5.6 g of Na ₂ CO ₃ powder was added 5 minutes after the start of the test. Thereafter, capsule formation occurred within 15 min and 60 μm
A mass of clumps with a diameter of . Total 60
The test was terminated after 1 minute. The mass was easily broken non-destructively into individual capsules on the specimen holder. Individual capsules have a diameter of 1-10 μm;
It was round, transparent, and had a smooth surface. Wet coating as in Example 2(a) made it possible to produce high quality back coated copy paper. Example 3(c) The process was as in Example 2. Additionally, 8.9 g of NaHCO ₃ powder was added 5 minutes after the start of the test.
Capsule formation then occurs within 10 minutes;
A relatively loose mass with a diameter of up to 230 μm was produced. The test was terminated after a total of 55 minutes. Return the slurry to the mixing siren to break up any clumps;
Then, the mixture was stirred at 3000 rpm for 5 minutes. A substantially lump-free slurry was then obtained, which contained round, transparent capsules with a smooth surface and a diameter of 1-14 μm. Wet coating as in Example 2(a) made it possible to produce high quality back coated copy paper. Example 3(d) The process was as in Example 2. Additionally, 15.8 g of triethanolamine was added 15 minutes after the start of the test. Capsule formation then occurred within 10 minutes, producing masses with diameters of up to 32 μm. The test was terminated after a total of 85 minutes. Return the slurry to the mixing siren to break up any clumps, and
The mixture was stirred at 3000 rpm for 3 minutes. The slurry then contained round, transparent capsules with a smooth surface and a diameter of 1-11 μm. Approximately 30% of the main smaller capsules produced masses up to 18 μm in diameter. A high quality back coated copy paper was produced by wet coating in the same manner as in Example 2(a). Spray - When dry, approximately 50% have a diameter of 1-11 μm
A capsule powder containing individual capsules and agglomerates up to 36 μm in diameter was given. Capsule powder was dissolved in a 2% polyvinyl alcohol solution (Mowiol 26/88, Hoechst, Frankfurt).
AG product) to give a coating formulation and then wet coating in the same manner as in Example 2(a)
Copy paper could be manufactured. Example 4 250 g of the protective colloid solution corresponding to Example 1(a) were added at room temperature into a glass beaker, followed by stirring (Kotov Mix Siren, 950 r.pm).
100 g of the color-former solution of Example 1(b) and 14 g
114 g of a mixture of diethyltolylene diamine were added. Then increase the rotation speed to 9000r.p. for 45 seconds.
m., a fine oil-in-water emulsifier was produced.
Reduce the rotation speed to 950r.pm for 15 seconds, then 125g
of protective colloid solution, 153 g of a clear solution consisting of 25 g of powdered sodium bisulfite adduct of biuretated hexamethylene diisocyanate and 3 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate (temperature 20°C).
was added. After the second emulsification step lasted for 45 seconds (with a mixing siren rotating at 9000 rpm), the slurry was transferred to a laboratory stirrer, and
700r for a total of 120 minutes while heating to 50℃.
Stirred at pm. A lump-free slurry containing round, transparent capsules with diameters ranging from 1 to 10 μm was obtained. A high quality CB-copier could be produced by wet coating in the same manner as in Example 2(a). Example 5 The steps to produce an oil-in-water emulsion were as in Example 4. After reducing the rotation speed to 950 rpm, 155 g of a solution consisting of 125 g of a protective colloid solution and 30 g of a sodium bisulfite adduct of powdered biuretted hexamethylene diisocyanate were added. 45 second emulsification stage (with mixing siren rotating at 9000r.pm)
After continuing for seconds, the slurry was transferred to a laboratory stirrer and stirred at 700 rpm for a total of 300 minutes while heating to 70°C. diameter is 1
A lump-free slurry was obtained containing round, transparent capsules that were within ~10 μm. High quality CB copy paper could be produced by wet coating in the same manner as in Example 2(a). Example 6 250 g of the protective colloid solution corresponding to Example 1(a) were added at 80° C. into a glass beaker, followed by stirring (Kotov mixing siren, 950 r.pm).
100 g of the color-former solution of Example 1(b) and 13.5
113.5 g of a mixture heated to 80.degree. The rotation speed was then increased to 9000 rpm for 45 seconds, producing an oil-in-water emulsion. Rotation speed is 950r.p. for 15 seconds.
m. and then 144 g of sodium bisulfite adduct of 125 g of protective colloid solution and 19 g of powdered hexamethylene diisocyanate.
Added the clear solution which had been heated to 0.degree. (900r.
After the second emulsification step (with a mixing siren running at pm) lasted for 45 seconds, the slurry was transferred to a laboratory stirrer and stirred for a total of 150 minutes while heating to 80°C. Diameter is 3~60μm
A lump-free slurry was obtained containing round, transparent capsules within the range of . A coating formulation was prepared by mixing 1 part by weight of the slurry with 3 parts by weight of a 2% polyvinyl alcohol solution (Mowiol 26/88, a product of Hoechst AG, Frankfurt). In the same way as Example 2(a)
CB-copy paper could be produced by wet coating using a 50 μm coating knife. Example 7 270 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at room temperature, followed by stirring (Kotov Mix Siren, 950 r.pm)
55 g of the color-former solution of Example 1(c) and 9.5 g
64.5 g of a mixture consisting of 3.0 g of diphenyltolylene diamine were added. Next, increase the rotation speed to 9000r for 45 seconds.
pm, a very fine oil-in-water emulsion was produced. Reduce the rotation speed to 950r.pm for 15 seconds,
Thereafter, 180 g of a protective colloid solution and 200 g of a room temperature clear solution consisting of 20 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate were added. After a second emulsification stage lasting 45 seconds (with a mixing siren rotating at 9000 rpm), the slurry was transferred to a 3-necked flask with a laboratory stirrer and a reflux condenser, and the slurry was combined while heating to 90 °C. Stirred for 180 minutes and further stirred for 120 minutes while cooling to room temperature. A lump-free slurry containing round, slightly opaque capsules ranging from 3 to 14 in diameter was obtained. High quality CB copy paper could be produced by wet coating in the same manner as in Example 2(a).
A dark green copy was obtained on the CF receiving paper. The copying properties of the paper were equally good after one month. The capsule powder obtained by spray drying consisted of round capsules with a wrinkled surface and a diameter of 3-11 μm. Approximately half of the capsules were agglomerated into nodules up to 18 μm in diameter. The powder was redispersed in a 2% polyvinyl alcohol solution (15 parts by weight of powder to 85 parts by weight of solution) to provide a coating formulation, which was used in Example 2.
By wet coating in the same manner as in (a), a high quality CB copying paper giving a dark green copy could be produced. Example 7(a) Fifteen minutes before the start of the test, 88 parts by weight of the color-former solution of Example 1(c) and 22 parts by weight of oxadiazinetrione in hexamethylene diisocyanate were heated to 80°C.
A clear solution was prepared by mixing at and cooling to room temperature. 250 g of the protective colloid solution corresponding to Example 1(a) were added at room temperature into a glass beaker, followed by stirring (Kotov Mix Siren, 950 rpm).
71 g of the previously prepared clear solution was added. After a 1 minute emulsification time, the emulsion was transferred to a laboratory stirrer and at 500 rpm for a total of 180 minutes. Two minutes into the test, 150g of water and 26.4g
of diethylenetriamine was added. After an additional 8 minutes, capsules were sufficiently stable that 10 minutes after the start of the test the slurry could be knife-coated onto a sheet of type paper as in Example 2(a) and the capsules could be broken. I was able to dry it without any problems. CB-paper was obtained, which produced an olive-green reproduction on the CF-receiver paper when written about 30 minutes after the start of the test. When I wrote on the CB-paper about 60 minutes after the start of the test,
The resulting copy was almost invisible. 180 minutes after the start of the test, the CB-copy paper had lost its copyability. The CB-paper produced with the slurry removed at 60 minutes and 120 minutes after the start of the test produced a thin copy from the beginning and was traceless after 2 hours. The slurry obtained at the end of the test was free of lumps. The capsules had a liquid content, a wrinkled surface and a diameter of 2-28 μm. Example 8 270 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at room temperature, followed by stirring (Kotov Mix Siren, 950 r.pm)
55g DAB7 paraffin oil (boiling range above 360°C)
and 9.5 g of diethyltolylenediamine were added. Then change the rotation speed to 45
When the speed was increased to 9000 rpm per second, a fine oil-in-water emulsion was produced. Reduce the rotation speed to 950 r.pm for 15 seconds, then add 180 g of protective colloid solution and 20 g
200 g of a clear solution at room temperature consisting of the sodium bisulfite adduct of powdered hexamethylene diisocyanate were added. After a second emulsification step lasting 45 seconds (with a mixing siren rotating at 9000 rpm), the slurry was transferred to a three-necked flask with a laboratory stirrer and a reflux condenser;
It was then stirred for a total of 180 minutes while heating to 90°C, and then stirred for an additional 120 minutes while cooling to room temperature. The resulting slurry contained capsules with diameters ranging from 3.5 to 31 μm and loose clumps of these capsules. Capsules were easily made into powder form by spray drying. Example 8(a) To prepare the isocyanate-containing organic phase, 88 parts of DAB7 paraffin oil (boiling range 360° C.
above) and 22 parts of hexamethylene diisocyanate are stirred at 80° C. for 5 minutes (Kotov mix siren, 9000 rpm) and cooled to room temperature to form a substantially unstable rather than a solution of the diisocyanate in paraffin oil. An emulsion was produced. 250 g of the protective colloid solution corresponding to Example 1(a) are added to a glass beaker at room temperature and then
71g while stirring at 950rpm (mixing siren)
An already prepared organic emulsion was added.
After a 1 minute emulsification time, the oil-in-water emulsion was transferred to a laboratory stirrer (500 rpm). Two minutes into the test, a solution consisting of 150 g of water and 64.4 g of diethylenetriamine was added, producing a mixture of solid urethane spheres and flakes in addition to unencapsulated paraffin oil droplets. DAB7 paraffin oil could not be encapsulated using this method. Example 8(b) The process of Example 8(a) was repeated, except that the oxadiazinetrione of hexamethylene diisocyanate was used instead of hexamethylene diisocyanate, and as a result only 26.4 g of diethylenetriamine was added. The results obtained are in Example 8.
It was the same as (a). Example 9 270 g of the protective colloid solution corresponding to Example 1(a) were added at room temperature into a glass beaker, followed by stirring (Kotov Mix Siren, 950 r.pm)
55 g partially hydrogenated terfenyl (Santosol 340, a product of the Monsanto Company)
and isohexadecane in a 1:1 ratio and 9.5 g of diethyltolylene diamine.
64.5g of mixture was added. The rotation speed was then increased to 9000 rpm for 45 seconds, producing a fine oil-in-water emulsion. Reduce the rotation speed to 950r.pm for 15 seconds,
Thereafter, 200 g of a clear solution at 20 DEG C. consisting of 180 g of a protective colloid solution and 20 g of powdered sodium bisulphite adduct of hexamethylene diisocyanate were added. After a second emulsification step lasting 45 seconds (with a mixing siren rotating at 9000 rpm), the slurry was transferred to a 3-necked flask with a laboratory stirrer and reflux condenser and heated to 90°C. Stirred for a total of 180 minutes while cooling to room temperature, then stirred for an additional 120 minutes while cooling to room temperature. The resulting slurry contained round transparent capsules with diameters in the range 1.4-12 μm, approximately 30% of which formed agglomerates up to 200 μm in size. Example 9(a) To prepare the isocyanate-containing organic phase:
88 parts by weight of partially hydrogenated terfenyl (Santosol 340, a product of Monsanto Company)
and isohexadecane and 22 parts by weight of oxadiazinetrione of hexamethylene diisocyanate were stirred at 80° C. for 5 minutes (Kotov Mix Siren, 9000 rpm) and then cooled to room temperature. Rather than a solution, a substantially unstable emulsion of the diisocyanate in the solvent was formed. 250 g of the protective colloid solution corresponding to Example 1(a) were added at room temperature into a glass beaker, followed by the addition of 71 g of the already prepared organic emulsion while stirring (mixing siren, 950 rpm). After 1 minute of emulsification time, the oil-in-water emulsion was heated at 500r.pm.
The sample was transferred to a rotating laboratory stirrer. Two minutes after the start of the test, a solution consisting of 150 g of water and 26.4 g of diethylenetriamine is added, which, in addition to unencapsulated paraffin oil droplets, also contains a mixture of solid polyurethaneurea spheres and solvent Large irregular clumps also formed. A 1:1 weight ratio mixture of partially hydrogenated terphenyl and isohexadecane could not be encapsulated by this method. Example 10 270 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at room temperature, followed by stirring (Kotov Mix Siren, 950 r.pm).
55 g partially hydrogenated terfenyl (Santosol 340, a product of the Monsanto Company)
and isohexadecane in a 1:1 ratio and 8.2 g of diethyltolylene diamine.
63.2g of mixture was added. The rotation speed was then increased to 9000 rpm for 45 seconds, producing a fine oil-in-water emulsion. Reduce the rotation speed to 950r.pm for 15 seconds,
Thereafter, 229.5 g of a clear solution (20 DEG C.) consisting of 180 g of a protective colloid solution and 49.5 g of a 40% aqueous solution of the sodium bisulfite adduct of isophorone diisocyanate were added. 45 second emulsification stage (with mixing siren rotating at 9000r.pm)
After continuing for 2 seconds, the slurry was transferred to a 3-necked flask equipped with a laboratory stirrer and reflux condenser and stirred for a total of 180 minutes while heating to 90°C, then for an additional 120 minutes while cooling to room temperature.
Stir for a minute. The resulting slurry is 1.4-150μm
contained capsules with diameters within a wide range of. Some of the capsules were spherical and opaque, but all contained a liquid core. Example 11 270 g of the protective colloid solution corresponding to Example 1(a) are added to a glass beaker at room temperature, followed by stirring (Kotov mixing siren, 950 r.pm)
64.5 g of a mixture consisting of 55 g of dodecylbenzene (Marlican S, a product of the Hulse Company of Mar) and 9.5 g of diethyltolyrundiamine was added. The rotation speed was then increased to 9000 rpm for 45 seconds, resulting in the formation of a fine oil-in-water emulsion. The rotation speed was reduced to 950 rpm for 15 seconds, after which 200 g of a clear solution (20° C.) consisting of 180 g of protective colloid solution and 20 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate were added.
After a second emulsification step lasting 45 seconds (with a mixing siren rotating at 9000 rpm), the slurry was transferred to a 3-necked flask with a laboratory stirrer and reflux condenser and heated to 90°C. Stirred for a total of 180 minutes while cooling to room temperature, then stirred for an additional 120 minutes while cooling to room temperature. The resulting slurry contained capsules with diameters ranging from 1 to 7 μm. Approximately 30% of the capsules have dimensions
It formed lumps up to 230 μm in size. Example 11(a) To prepare an isocyanate-containing organic phase, 88 parts by weight of dodecylbenzene and 22 parts by weight of hexamethylene diisocyanate in the oxadiazinetrione were stirred at 80° C. for 5 minutes (Kotov mix siren, 9000 rpm). pm), then cooled to room temperature. Rather than a solution of the diisocyanate in the solvent, a substantially unstable emulsion was produced. 250 g of the protective colloid solution corresponding to Example 1(a) were added at room temperature into a glass beaker, followed by the addition of 71 g of the already prepared organic emulsion while stirring (mixing siren, 950 rpm). After 1 minute of emulsification time, the oil-in-water emulsion was heated at 500r.pm.
The sample was transferred to a laboratory stirrer that was being rotated. Addition of a solution consisting of 150 g of water and 26.4 g of diethylenetriamine 2 minutes into the test produces solid polyurethaneurea spheres and pieces, some of them together, in addition to unencapsulated solvent droplets. It hardened to form relatively large irregular lumps. Dodecylbenzene could not be encapsulated using this method. Example 12 125 g of the protective colloid solution corresponding to Example 1(a) are added to a glass beaker at room temperature, followed by stirring (Kotov Mix Siren, 950 r.pm)
13.2 g of the color-former solution of Example 1(c) and 2.2
15.4 g of a clear solution consisting of g of diethyltolylene diamine was added. Then increase the rotation speed for 45 seconds
When the speed was increased to 9000 rpm, a fine oil-in-water emulsion was formed. Reduce the rotation speed to 950r.pm for 30 seconds,
90 then made at room temperature approximately 15 minutes before the start of the test.
g of a protective colloid solution and 10 g of an isomer mixture of tolylene diisocyanate (80% 2,4-
100 g of a clear solution consisting of sodium bisulfite adduct of TDI and 20% 2,6-TDI) was added. After a second emulsification step lasting 60 seconds (with a mixing siren rotating at 9000r.pm), the slurry was transferred to a laboratory stirrer and heated to 50°C at 700rpm for a total of 180 minutes. Stirred. A slurry was obtained containing capsules with a wrinkled surface and a diameter in the range of 1-15 μm. High quality CB-copy paper could be produced by wet coating using a 40 μm coating knife as in Example 2(a). A dark green copy was obtained on the CF-receiver paper. Copyability was still good even after one month. Example 12(a) 15 minutes before the start of the test, 81 parts by weight of the color of Example 1(c). generator solution and 19 parts by weight of an isomer mixture of tolylene diisocyanate (80% 2,4-TDI
and 20% 2,6-TDI) at 80° C. and cooling the resulting mixture to room temperature, a clear solution was prepared. Example 1(a) of 135g
The corresponding protective colloid solution was added at room temperature into a glass beaker, followed by the addition of 34.1 g of the previously prepared solution while stirring (Kotov mix siren, 950 rpm). Increase the rotation speed to 9000r.pm, and after 45 seconds emulsification time, 500r.pm
The sample was transferred to a laboratory stirrer that was being rotated. After 30 seconds, a clear solution consisting of 87 g water and 13 g diethylenetriamine was added and then stirred for a total of 120 minutes. wrinkled surface and 1~
A lump-free slurry containing transparent capsules with a diameter of 14 μm was obtained. When written on CB-copy paper produced by wet coating as in Example 2(a), CF
- A red copy was obtained on the receiving paper. The color-forming agent apparently underwent considerable chemical changes as a result of the reaction with the diisocyanate. 24 hours after slurry production
Over time, the capsules had lost their reproduction power both on the manufactured CB-paper and in the slurry itself. Example 13 270 g of the protective colloid solution corresponding to Example 1(a) were added at 70° C. to a glass beaker, followed by stirring (laboratory stirrer, 500 rpm) to 11 g.
of diethanolamine, 30 g of Marlican S and 30 g of diethyltolylenediamine.
A mixture of was added. A very fine oil-in-water emulsion was produced. 25 seconds after addition of the amine mixture,
200 g of a clear solution heated to 70° C. consisting of 180 g of a protective colloid solution and 20 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate were added. The capsule wall formed very rapidly, i.e. in about 10 minutes. This was reflected in the thickening of the slurry. The slurry was stirred for a total of 40 minutes at an increased rotational speed of 700 rpm. A lump-free slurry with a round wrinkled surface and a diameter in the range of 1-11 μm was produced. The capsules contained a mixture of solvent and amines. Example 14 5 parts by weight of polyvinyl alcohol (Mowiol)
26/88, product of Hoechst AG, Frankfurt),
A protective colloid solution was prepared by stirring 10 parts by weight of xanthan (Kelzan D, a product of Kelco Division of Baltimore Air Coil/Kembion SA) and 1985 parts by weight of distilled water at room temperature. Add 270 g of protective colloid solution into a glass beaker at 70 °C, then stir at 500 rpm (laboratory stirrer, 6 blades, 3 cm length, 1 cm
30g of diethyltolylenediamine was added. A very fine oil-in-water emulsion was produced. Thirty seconds after addition of the diamine mixture, 200 g of a clear solution heated to 70° C. consisting of 180 g of a protective colloid solution and 20 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate were added. The rotation speed was increased to 700 rpm and then stirred at 70° C. for a total of 70 minutes. then 3~18μm
Spherical, smooth, transparent capsules with diameters in the range of . The slurry was completely free of lumps. After cooling to room temperature, the slurry was dried in a laboratory spray dryer (Swiss Fukail CH-
9230 in a Butuchi Company mini spray dryer). A pale yellow capsule powder free of finely divided lumps was obtained. The capsules had the same diameter distribution as in the slurry and were spherical, but with rounded surfaces and opaque. Example 15 The steps were as in Example 14 up to the first addition of diethyltolylene diamine. 30 seconds after addition of the diamine mixture, add 122.5 g of a clear solution heated to 70° C. consisting of 180 g of protective colloid solution and 12.5 g of sodium bisulphite adduct of powdered biuretated hexamethylene diisocyanate. did. rotation speed
The temperature was increased to 700 rpm and then stirred at 70° C. for a total of 70 minutes. Spherical opaque capsules with round surfaces and diameters of 4-28 μm were produced. Spray drying under the same conditions as Example 14 resulted in a fine, free-flowing capsule powder containing some hard capsules. Example 16 A fine emulsion of diethyltolylenediamine in a protective colloid solution was prepared in the same manner as in Example 14. Thirty seconds after addition of the diamine mixture, 200 g of a clear solution consisting of 180 g of protective colloid solution and 20 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate were added. The rotation speed was increased to 700 rpm and then held for a total of 70 minutes. A slurry was obtained containing spherical smooth transparent capsules with a diameter of 5-18 μm. This slurry was spray dried under the same conditions as in Example 14, resulting in a very fine, slightly hard capsule powder. Example 17 A fine oil-in-water emulsion in a protective colloid solution of diethyltolylenediamine was prepared in the same manner as in Example 14. 30 seconds after adding the diamine mixture,
247.5 g of a 40% aqueous solution of sodium bisulfite adduct of 180 g of protective colloid solution and 67.5 g of trimer of hexamethylene diisocyanate (calculated shielded NCO-content 7.8%)
A clear solution heated to 65°C was added. Increase the rotation speed to 700r.pm, and the emulsion to a total of 70
Stir for a minute. A lump-free, sediment-free slurry containing rounded surfaces and spherical capsules with a diameter of 2.5-20 μm was produced. Example 18 810 g of a protective colloid solution of the type used in Example 14 was added to a glass beaker at 70°C and then
While stirring at 700r.pm (laboratory stirrer,
(6 blades, 3 cm length, 1 cm width) 90 g of diethyltolylenediamine were added. A very fine oil-in-water emulsion was produced. One minute after the addition of the diamine mixture, 707 g of a clear solution heated to 65 DEG C. was added consisting of 540 g of a protective colloid solution and 167 g of a 40% aqueous solution of the sodium bisulfite adduct of isophorone diisocyanate. After 3 minutes,
Kotov mixed siren (type) glass beaker
DE032S) and emulsified for 2 minutes at 5320 rpm. 700r.pm while heating the emulsion to 70℃
The mixture was stirred for an additional 65 minutes using a stirrer used in the same laboratory. A lump-free, sediment-free slurry was produced containing spherical transparent capsules with a smooth surface and a diameter in the range of 1-17 μm. Spray drying resulted in a lump-free capsule powder. The powder capsules were spherical, opaque, and had a wrinkled surface. Example 19 25 parts by weight of biuretated hexamethylene diisocyanate (Desmodur N, Bayer AG)
product) was mixed with 28 parts by weight of the capsules of Example 5 to form a paste, which was then heated to 120° C. for 10 minutes. The material began to solidify above 70°C and became brittle and hard when it reached 120°C. A sample of the same polyisocyanate without capsules heated in the same manner remained liquid. A sealed sample of the above polyisocyanate-capsule mixture retained its pasty consistency for at least 8 days at room temperature. Example 20 100 parts by weight of a chlorobenzene solution containing 25% biuretated hexamethylene diisocyanate was mixed with 28 parts by weight of the capsules of Example 5, and the resulting mixture was heated at 120° C. for 10 minutes. During heating, the substance hardens,
A shock-resistant solid was produced. Sealed samples of the polyisocyanate-capsule mixture described above remained liquid at room temperature for at least 8 days. Example 21 A fine emulsion of diethyltolylenediamine in a protective colloid solution was prepared in the same manner as in Example 14. 245 consisting of a 40% aqueous solution of a sodium bisulfite adduct of a mixture of 180 g of a protective colloid solution and 65 g of a mixture of 41 parts of isophorone diisocyanate and 59 parts of biuretated hexamethylene diisocyanate 30 seconds after addition of the diamine mixture.
g of the clear solution, which had been heated to 65°C, was added.
The rotation speed was then increased to 700 rpm, the temperature was increased to 70° C., and the emulsion was stirred for a total of 70 minutes. A lump-free, precipitate-free slurry was obtained. The capsules were spherical, had a smooth surface, were partially opaque, and had a diameter of 1.5-15 μm. Example 22 A fine emulsion of diethyltolylenediamine in a protective colloid solution was prepared in the same manner as in Example 18. One minute after the addition of the diamine mixture, 540 g of the protective colloid solution, 30 g of the sodium bisulfite adduct of powdered hexamethylene diisocyanate and 47 g of the sodium bisulfite adduct of biuretated hexamethylene diisocyanate were added.
617 g of a clear solution heated to 65° C. was added. After 3 minutes, transfer the glass beaker to a Kotov mixing siren (type DE 032S) and
Then, it was emulsified for 2 minutes at 5320 rpm. 70 emulsion
The mixture was stirred for an additional 65 minutes at 700 r.pm (using the same laboratory stirrer) while heating to °C. A lump-free, sediment-free slurry was produced containing capsules with diameters ranging from 1 to 16 μm. The capsules were primarily smooth, transparent, and spherical, and the larger capsules were irregular in shape, opaque, and had a wrinkled surface. The spray-dried capsule powder exhibits good free-flowing properties, is irregular in shape, opaque,
and had liquid-filled capsules with wrinkled surfaces and masses up to 75 μm in size. Example 23 Fifteen minutes before the reaction, a sodium bisulfite adduct of 3 parts by weight of an isomer mixture of tolylene diisocyanate (80% 2,4-TDI and 20% 2,6-TDI) is added with stirring. Example by adding
A clear solution of 25 parts by weight of the protective colloid solution used in 14 was prepared at room temperature (approximately 23°C). Add 135 g of already used protective colloid solution into a glass beaker at room temperature and then add at 500 r.p.
15 g of diethyltolylene diamine were added while stirring (laboratory stirrer) at m. A very fine oil-in-water emulsion was produced. Thirty seconds after addition of the diamine mixture, 100.0 g of the previously prepared bisulfite adduct solution was added. The rotation speed was increased to 700 rpm and held for a total of 70 minutes. The emulsions and slurries remained at room temperature during the test period. A lump-free, precipitate-free slurry was produced.
The capsules are spherical, transparent, with a slightly wrinkled surface and a diameter of 1-170 μm. Spray drying resulted in a slightly lumpy capsule powder. The capsule was opaque and had a more wrinkled surface and a liquid core. Example 24 270 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at 80°C and then
While stirring at 700r.pm (laboratory stirrer)
Consisting of 10.5 g 4,4'-diaminodiphenyl-methane and 9.5 g diethyltolylenediamine
20g of liquid diamine mixture heated to 80°C was added. 25 seconds after addition of the diamine mixture, 200 g of protective colloid solution and 20 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate were added. The mixture was stirred at 700 rpm and 80°C for a total of 70 minutes. After cooling to room temperature, approximately 10% of the capsules
A slurry was obtained which appeared to form agglomerates with dimensions up to 35 μm. The individual capsules appeared partly transparent and partly opaque, with wrinkled or grooved surfaces and solid cores. Example 25 135 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at 70°C and then
While stirring at 500r.pm (laboratory stirrer)
15 g of diaminomethylated cyclododecane, which is liquid at room temperature, was added. A very fine oil-in-water emulsion was produced. Twenty-five seconds after the addition of the diamine mixture, 112.5 g of a clear solution heated to 70° C. was added consisting of 90 g of a protective colloid solution and 22.5 g of a 40% aqueous solution of the sodium bisulfite adduct of isophorone diisocyanate. The slurry was stirred at 500 rpm and 70°C for a total of 70 minutes. The resulting slurry contains very small capsules with diameters ranging from 1 to 3 μm;
Most of them were solidified into small lumps with diameters of less than 10 μm. Example 26 270 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at 75°C and then
While stirring at 500r.pm (laboratory stirrer)
30 g of diphenylmethane-3, which is liquid at 75°C;
3'-dithiomethyl-4,4'-diamine was added. 25 seconds after addition of the diamine mixture, 115 g of a clear solution heated to 75° C. consisting of 180 g of a protective colloid solution and 15 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate was added. The rotation speed was increased to 700 rpm and kept at a temperature of 75°C for a total of 120 minutes. Diameter is 1~
A lump-free slurry containing polyamide-filled microcapsules in the 12 μm range was produced. Example 27 135 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at 70°C and then
While stirring at 500r.pm (laboratory stirrer)
14.3% of hexamethylene diisocyanate
15 g of a polyamine (6-amino-n-hexylcarbamine dipropylene glycol diester) was added. 25 seconds after the addition of the diamine mixture, 102.5 g of a clear solution heated to 70° C. was added consisting of 90 g of a protective colloid solution and 12.5 g of a 40% aqueous solution of the sodium bisulfite adduct of isophorone diisocyanate. The slurry was stirred at 500 rpm and 70°C for a total of 70 minutes. The resulting slurry was primarily lemon-shaped capsules with a spherical core, as is known from the manufacture of microcapsules by complex coacervation. The diameter of the capsules ranged from 9 to 230 μm. Example 28 270 g of the protective colloid solution corresponding to Example 1(a) were added to a glass beaker at 98°C and then
While stirring at 500r.pm (laboratory stirrer)
Diphenylmethane-3,5-diethyl-3',5'-
Diisopropyl-4,4'-diamine, diphenylmethane-3,3',5,5'-tetraisopropyl-
4,4'-diamine and diphenylmethane-3,
30 g of a polyamine mixture heated to 98 DEG C. consisting of 3',5,5'-tetraethyl-4,4'-diamine was added. 25 seconds after addition of the diamine mixture, 193 g of a clear solution heated to 98° C. consisting of 180 g of a protective colloid solution and 13 g of powdered sodium bisulfite adduct of hexamethylene diisocyanate was added. Increase the rotation speed to 700r.pm for 1 minute,
The slurry was then transferred to a 1 liter 3-necked flask equipped with a reflux condenser, and the slurry was
Reflux for 4.5 hours and stir (300 rpm).
The resulting slurry contained polyamide-filled microcapsules ranging in diameter from 1 to 13 μm. Approximately 5% of the capsules were stuck together, producing clumps up to 24 μm in diameter. Example 29 10 g of the capsule powder obtained according to Example 14 were mixed with 190 g of trimethylolpropane-starting polyester containing more than 80% of primary OH groups (OH number 35). The resulting dispersion was then treated with 6 g H ₂ O, 2 g diethanolamine, 0.5
g diazabicyclooctane, 4 g tris-2
- chloroethyl phosphate and 0.25 g of tin() dioctate. After thorough mixing, 77.4 g of tolylene diisocyanate (isomer mixture: 80% 2,4- and 20% 2,6-
-tolylene diisocyanate) was added with rapid stirring and the foamable mixture was poured into the open mold. After a rise time of 83 seconds, an open-celled flexible foam was obtained. The foam was then worked up in an oven at 120°C for 1 hour. A highly elastic flexible foam with favorable mechanical properties was obtained.

Claims (1)

[Scope of Claims] 1. A microcapsule comprising a capsule wall and a hydrophobic core material produced by the reaction of a water-insoluble polyamine and a water-soluble polyisocyanate bisulfite adduct. 2. The microcapsule according to claim 1, which has a diameter of 0.2 to 2000 μm. 3. A microcapsule according to claim 1, wherein the wall constitutes 5 to 64% by weight of the capsule. 4. The microcapsule according to claim 1, wherein the core substance is a water-insoluble polyamine. 5 emulsify the mixture of hydrophobic core material and water-insoluble polyamine in water or aqueous protective colloid solution, add water-soluble polyisocyanate bisulfite adduct in the form of powder or aqueous solution, and add the mixture to 1
Production of microcapsules consisting of a capsule wall and a hydrophobic core material produced by the reaction of a water-insoluble polyamine with a water-soluble polyisocyanate bisulfite adduct, characterized in that the reaction is carried out to completion at a temperature of ~140°C. Method. 6 The water-insoluble components of the emulsion are between 0.5 and 50.
% by weight.