EP0000911A1 - Process for lowering the viscosity of formose, the resulting mixtures, their use to prepare polyurethanes which may or may not be cellullar and the preparation of esters of phosphorous acid and formose - Google Patents

Abstract

The viscosity of formose or mixtures of formose and mono- and/or disaccharides is lowered by adding a viscosity-lowering agent in the form of a dialkyl phosphite.

Description

In the broadest sense, the present invention is directed to a process for lowering the viscosity of formose (or mixtures of formose with mono- or disaccharides and / or aminoplast monomers and / or water) by adding dialkyl phosphites and optionally trialkyl phosphites and / or α-hydroxyphosphonic acid esters. The invention further relates to mixtures of formose, dialkyl phosphites and optionally water and / or mono- or disaccharides and / or aminoplast monomers and / or trialkyl phosphites and / or α-hydroxyalkylphosphonic esters and / or α-hydroxyalkylphosphonic esters and / or α-aminoalkylphosphonic esters which are liquid and have a low viscosity and areocyanate-reactive mixtures of formose, dialkyl phosphites and optionally the use of such reactive organic materials for the production of polyurethane plastics, in particular foams.

“Formose” is understood according to the invention to mean the mixtures of low molecular weight polyhydroxyl compounds (polyhydric alcohols, hydroxyaldehydes and hydroxyketones) known per se, which result from the condensation of formaldehyde hydrate.

The preparation of mixtures of polyhydric alcohols, hydroxy aldehydes and hydroxy ketones by self-condensation of the formaldehyde hydrate is described in numerous references. For example, Butlerow and Loew, Annalen 120, 295 (1861) and J.pr.Chem. 33, 321 (1886), Pfeil, chemical reports 84, 229 (1951), Pfeil and Schroth, chemical reports 85, 303 (1952), R.D. Partridge and A.H. Weiss, Carbohydrate Research 24, 29-44 (1972), the formoses of glyceraldehyde or dioxyacetone according to Emil Fischer, the German patents 822 385, 830 951 and 884 794, the US patents 2,224,910, 2,269,935 and 2,272 378 and the English patent specification 513 708. However, these known processes of the prior art have certain disadvantages (toxicologically unsafe catalysts, poor space-time yields, colored by-products!). Recently, the applicant has developed new processes which are practical in high yield with conventional catalysts Have colorless and free from troublesome by-products.

• Verbindungen mit 3 C-Atomen/Verbindungen mit 4 C-Atomen: 0,5 bis 2,0
• Verbindungen mit 4 C-_Atomen/Verbindungen mit 5 C-Atomen: 0,2 bis 2,0
• Verbindungen mit 5 C-Atomen/Verbindungen mit 6 C-Atomen: 0,5 bis 5,0

wobei der Anteil der Komponenten mit 3 bis 6 C-Atomen mindestens 75 Gew.-t, vorzugsweise mehr als 85 Gew.-%, bezogen auf gesamten Co-Katalysator, beträgt.One of these new processes consists in the condensation of the formaldehyde hydrate in the presence of soluble or insoluble lead (II) salts or lead (II) ions bound to high molecular weight carriers as a catalyst and a mixture of hydroxyaldehydes and hydroxyketones as co- Catalyst can run off, as it occurs during the condensation of formaldehyde hydrate and which is characterized by the following molar ratios:

• Compounds with 3 carbon atoms / compounds with 4 carbon atoms: 0.5 to 2.0
• Compounds having 4 C _A Tomen / compounds having 5 carbon atoms: 0.2 to 2.0
• Compounds with 5 carbon atoms / compounds with 6 carbon atoms: 0.5 to 5.0

wherein the proportion of components with 3 to 6 carbon atoms is at least 75% by weight, preferably more than 85% by weight, based on the total cocatalyst.

The reaction temperature is generally between 70 and 110 ° C, preferably between 80 and 100 ° C, and the pH of the reaction solution is controlled by adding an inorganic or organic base up to a conversion of 10-60%, preferably 30- 50 1, to a value of 6.0-8.0, preferably 6.5-7.0 and then to a value of 4.0-6.0, preferably 5.0-6.0. Surprisingly, the product distribution of the corresponding polyol, hydroxyaldehyde and hydroxyketone mixtures can be reproduced in a reproducible manner by this special pH control and by subsequent cooling at different levels of residual formaldehyde (0 to 10% by weight, preferably 0.5 to 6% by weight) Ways vary.

After the self-condensation of the formaldehyde hydrate has been interrupted by cooling and / or by deactivation of the lead-containing catalyst by means of acids, the catalyst is optionally removed in a manner known per se and the water contained in the products is evaporated. For further details, reference is made to German Offenlegungsschrift 2,639,084.

A further possibility of producing highly concentrated colorless formoses in a high space-time yield consists in aqueous formalin solutions and / or paraformaldehyde dispersions in the presence of a soluble or insoluble metal catalyst and one by partial oxidation of a di- or polyvalent, having at least two adjacent hydroxyl groups To condense alcohol with a molecular weight between 62 and 242 or a mixture of such alcohols co-catalyst, the pH of the reaction solution being controlled by controlled addition of a base up to a conversion of 5 to 40% between 6.0 and 9, Holds 0 and then adjusts to 4.5 to 8.0 until the condensation reaction is terminated, so that it is now 1.0 to 2.0 units lower than in the first reaction phase, then the reaction with a residual content of 0-10 % By weight of formaldehyde is interrupted by deactivating the catalyst and the catalyst is removed. This procedure is described in detail in DOS 2 714 084.

High-quality formoses can also be produced by condensation of formaldehyde in the presence of a metal catalyst and more than 10% by weight, based on formaldehyde, of one or more dihydric or polyhydric low molecular weight alcohols and / or higher molecular weight polyhydroxyl compounds. Formose-polyol mixtures of this type are the subject of DOS 2,714,104.

It is particularly economical to produce formose directly, ie without the detour via aqueous formalin solutions or paraformaldehyde, from synthesis gases containing formaldehyde. For this purpose, the synthesis gases are led, as in the occur large-scale production of formaldehyde, bsorptionsflüssigkeit in an _A at temperatures between 1 ₀ and ₁₅₀ ⁰ C continuously or intermittently, which, once from water or polyhydric low molecular weight alcohols and / or higher molecular weight polyhydroxyl compounds and / or capable of enediol compounds as co-catalyst and / or soluble or insoluble metal compounds, which may be bound to high molecular weight carriers, exist as a catalyst and have a pH of 3 to 10, the formaldehyde condenses directly in situ in the absorption liquid (optionally also in a downstream reaction tube or a downstream one Stirred tank cascade), the self-condensation of the formaldehyde at a residual formaldehyde content in the reaction mixture of 0 to 10% by weight is terminated by cooling and / or by deactivation of the catalyst by means of acids and finally removes the catalyst. With regard to further details of this procedure, reference is made to German Offenlegungsschrift 2,721,093.

The formoses prepared in this way can also subsequently be converted into their hemiacetals by excess formaldehyde or α-methylolated by reaction with formaldehyde in the presence of bases. Modified forms of this type are also described in more detail in DOS 2 721 186.

Depending on how the formaldehyde condensation is carried out, the properties of the formose (average hydroxyl functionality; degree of branching; content of reducing groups) can be varied within wide limits. In general, the average molecular weight and thus the hydroxyl functionality of the formoses, the higher the further Condensation reaction is carried out, ie the less residual formaldehyde is present when the condensation reaction is terminated. For example, if the condensation reaction is carried out up to a residual formaldehyde content of 0 to 1.5% by weight, a formose is obtained which contains approx. 25% by weight of 5-carbon atoms and 45% by weight Contains compounds with 6 carbon atoms and about 20 wt .-% of compounds with 7 and more carbon atoms. In contrast, only about 10% of polyols, hydroxyketones and hydroxyaldehydes with 2.3 and 4 carbon atoms are obtained. This corresponds to an average hydroxyl functionality of approx. 5.

As explained above, other component distributions of the starter mixtures are obtained by stopping the self-condensation of formaldehyde at somewhat higher residual formaldehyde. If the condensation reaction is terminated at a formaldehyde content of 2 to 2.5%, a mixture of polyhydric alcohols, hydroxyaldehydes and hydroxyketones with an average hydroxyl functionality of approx. 4 results. Still other component distributions with a further reduced average hydroxyl functionality are obtained if the condensation reaction is maintained with residual formaldehyde cancels that are even higher than 2.5.

By mixing the formose with di- or higher-functional low-molecular alcohols, the functionality of the products can optionally be varied further in the desired manner if certain application effects are to be achieved. Examples of such low molecular weight polyhydric alcohols (molecular weights up to approx. 300) are ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, triethylene Glycol, tetraethylene glycol, _D ibutylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, butane triols and hexane triols as well as oxyethylation products of these alcohols or also hydrogenated formose (formite) in question. The use of amines and / or ethanolamines as a blending component is also possible.

Examples include _M ONO, _D i and triethanolamine, mono-, di- and triisopropanolamine, _{N-alkanolamines,} such as N-ethanolamine and N-Methyldi- Äthyldiäthanolamin and lower aliphatic mono- and polyamines, such as ethylamine, ethylenediamine, diethylenetriamine and Triethylene tetramine.

According to our own older proposals (see in particular the German Offenlegungsschriften 26 39 084, 27 14 084 and 27 14 104 already mentioned above), formoses can be used as a polyol component in the polyisocyanate polyaddition process for the production of polyurethane plastics. It has now been found that polyurethane plastics, in particular foams, can be produced in this way with extremely high flame resistance if a mixture of formose and dialkylphosphites is used as the starting component instead of the pure formose. Compared to pure formose, mixtures of this type have a surprisingly low viscosity, which is of great advantage in terms of application technology; because the mixtures are easy to dose. The mixtures of formose and dialkyl phosphites also surprisingly have the ability to dissolve large amounts of crystallized sugars (mono- and / or disaccharides). To further reduce the viscosity or other chemical modification, compounds capable of aminoplast formation can also be added to the mixtures according to the invention.

The invention thus relates to a process for reducing the viscosity of formoses by adding a viscosity-reducing agent, which is characterized in that dialkyl phosphites, optionally in a mixture with trialkyl phosphites and / or α-hydroxyalkylphosphonic acid esters and / or α-aminoalkylphosphonic acid esters and / or or compounds capable of aminoplast formation.

• A) 3 bis 97 Gew.-%, vorzugsweise 10 bis 95 Gew.-%, besonders bevorzugt 30 bis 80 Gew.-%, bezogen auf die Summe der Komponenten A, B und C, an Formose sowie gegebenenfalls Mono- und/oder Disacchariden,
• B) 3 bis 97 Gew.-%, bevorzugt 5 bis 90 Gew.-%, besonders bevorzugt 15 bis 60 Gew.-%, bezogen auf die Summe der Komponenten A, B und C, an Dialkylphosphiten sowie gegebenenfalls Trialkylphosphiten und/oder d-Hydroxyalkylphosphonsäureestern und/oder α-Aminoalkylphosphonsäureestern und
• _C) 0 bis 10 Gew.-%, vorzugsweise 0,3 bis 6 Gew.-%, bezogen auf die Summe der Komponenten A, B und C, an Wasser.

The invention also relates to mixtures of isocyanates reactive

• A) 3 to 97% by weight, preferably 10 to 95% by weight, particularly preferably 30 to 80% by weight, based on the sum of components A, B and C, of formose and optionally mono- and / or Disaccharides,
• B) 3 to 97% by weight, preferably 5 to 90% by weight, particularly preferably 15 to 60% by weight, based on the sum of components A, B and C, of dialkyl phosphites and optionally trialkyl phosphites and / or d -Hydroxyalkylphosphonic acid esters and / or α-aminoalkylphosphonic acid esters and
• _C ) 0 to 10 wt .-%, preferably 0.3 to 6 wt .-%, based on the sum of components A, B and C, of water.

The mixtures according to the invention are preferably 0.2 to 20 mol per mole of component A, particularly preferably 0.7 to 5 moles of component _B and 0 to 3 moles, particularly preferably 0 to 1.5 moles, of water.

The mixtures according to the invention can furthermore optionally also up to 100 _G ew. parts, preferably 10 to 50 parts by weight, based on 100 parts by weight of the mixture of A, B and C, contain at aminoplast. Preferably 0.5 to 3 moles of substances capable of aminoplast formation per mole of component A are present in the mixtures according to the invention.

In principle, any formoses are suitable for the mixtures according to the invention; for the preferred use according to the invention (production of polyurethane plastics), however, it is advantageous to use the formoses produced by the applicant's more recent processes described above, since they are generally colorless and free of disruptive by-products. Formoses are preferably used which have an average molecular weight between 92 and 360, particularly preferably between 100 and 240, and a sugar content (calculated as glucose with a molecular weight of 180) of 4 to 85% by weight, particularly preferably 6-72% by weight. %, exhibit. Because of their higher content of primary hydroxyl groups, formoses are preferred for some applications which, as described above, have been α-aldolized by subsequent treatment with formaldehyde in basic pH ranges. Formoses can of course also be used according to the invention, which have been converted into hemiacetals after their production by reaction with formaldehyde, or by subsequent treatment with acids with inter- or intramolecularly acetalized or ketalized formoses, or also by adding carbonyl compounds which have no hydroxyl group at the 4-position carbon atom, or by Maillard reaction, be used by acyloin condensation in the presence of cyanides or formoses modified by phenoplast formers. All of these modified formoses also fall under the term "formose" within the meaning of the present invention.

As already mentioned, surprisingly, relatively high amounts of crystallized mono- and disaccharides such as glucose, maltose or cane sugar are soluble in the mixtures according to the invention, as are natural invert sugars (e.g. bee honey) or artificial invert sugars, e.g. Hydrolysates of cane sugar, but also degradation products of corn and potato starch and pectin substances (amylose and amylopectins) or hydrolysates of any other di- and / or polysaccharides, e.g. of trehalose, galactose, raffinose, cellulose and dextrins. This is of particular technical interest because such crystallized mono- or disaccharides are difficult to react with polyisocyanates in pure form.

All of these sugars can be present in component A in proportions of up to 70% by weight, preferably up to 50% by weight (based on component A).

As component B in the mixtures according to the invention, preference is given to dialkyl phosphites which contain alkyl groups having 1 to 3 carbon atoms; dimethyl phosphite and diethyl phosphite are particularly preferred. In addition, phosphites with benzyl, cycloalkyl or alkyl groups with 4 to 8 carbon atoms can also be used. Optionally, the component B and up to 80 _G ew .-%, preferably up to 50 wt .-%, of the corresponding trialkyl phosphites and / or α-hydroxyalkylphosphonic acid esters and / or 4-Aminoalkylphosphonsäureestern included.

wobei

• R' für Wasserstoff, eine Alkyl-, Cycloalkyl-, Aryl- oder Aralkylgruppe und
• R" für eine Alkyl-, Cycloalkyl-, Aralkyl- oder Arylgruppe oder zusammen mit R' für einen alicyclischen Ring stehen.

As is known, α-hydroxyalkylphosphonic acid esters are addition products of dialkylphosphites to aldehydes or ketones, for example according to the following formula:

in which

• R 'represents hydrogen, an alkyl, cycloalkyl, aryl or aralkyl group and
• R "stands for an alkyl, cycloalkyl, aralkyl or aryl group or together with R 'for an alicyclic ring.

Suitable aldehydes and ketones are, for example, those with 1 to 15, particularly preferably 1 to 9, carbon atoms, for example formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, mesityl oxide, isophorone, acetophenone and their methylol derivatives, as they are obtainable by base-catalyzed partial or complete aldolization with formaldehyde on the C atoms α to the carbanyl group.

wobei

• R und R' die oben angegebene Bedeutung haben,
• R™ für einen einwertigen aliphatischen, cycloaliphatischen oder araliphatischen Rest
  mit 1 bis 15, vorzugsweise 2 bis 12, C-Atomen steht und
• R"" einen zweiwertigen aliphatischen, cycloaliphatischen oder araliphatischen Rest mit 2 bis 15, vorzugsweise 2 bis 12, C-Atomen darstellt.

α-Aminoalkylphosphonic esters result from the addition of dialkylphosphites to aldimines or ketimines of the abovementioned aldehydes or ketones with monoamines or preferably polyamines (in particular diamines such as tetramethylene diamine, pentamethylene diamine, hexamethylene diamine and 1-amino-3-aminomethyl-3,5,5-trimethylcyclo) ), e.g. according to the following formula:

in which

• R and R 'have the meaning given above,
• R ™ for a monovalent aliphatic, cycloaliphatic or araliphatic radical
  with 1 to 15, preferably 2 to 12, C atoms and
• R "" represents a divalent aliphatic, cycloaliphatic or araliphatic radical having 2 to 15, preferably 2 to 12, carbon atoms.

The α-hydroxyalkylphosphonic acid esters or x-aminoalkylphosphonic acid esters are also compounds which are reactive toward isocyanates and which are incorporated into the resulting polyurethane plastics when the mixtures according to the invention are reacted with polyisocyanates.

As already mentioned, aminoplast monomers can also be added to the mixtures according to the invention for further modification. All substances known per se which are capable of forming aminoplast are suitable for this purpose, as are described, for example, in German Offenlegungsschriften 2,324,134 and 2,713,198. In general, it is preferred to use the N-methylolation products of these compounds since they can be more easily incorporated into the polyurethane plastics in the reaction with polyisocyanates.

Aminplast monomers preferred according to the invention are urea, symmetrically or asymmetrically substituted ureas such as N, N-dimethyl (or -diethyl or -dibutyl) urea, thiourea, dicyandiamide, melamine, oxamide, ethylene urea, F-caprolactam, pyrrolidone (2) , Aniline, acetylene diurein and the N-methylol compounds of all these monomers. According to the invention, urea, N-monomethylolurea, N, N-dimethylolurea, thiourea, N-monomethylolthiourea, N, N-dimethylolthiourea, ε-caprolactam and N-methylol-f-caprolactam are particularly preferred.

As is known, natural sugars such as D-glucose, D-fructose, D-galactose, maltose, lactose and cane sugar only dissolve very little or are completely insoluble in polar organic solvents, both at room temperature and when heated to approx. 100 ° C. Most mono- and disaccharides such as glucose, galactose, fructose and lactose are practically insoluble at room temperature in methanol or ethanol; Cane sugar only slightly dissolves in methanol or ethanol at room temperature after long dissolving times by 1% by weight. This low solubility of mono- and polysaccharides in Other organic compounds are largely responsible for the fact that these sugars, when used in polyurethane formulations, essentially only take on the function of a filler and participate in the polyisocyanate polyaddition reaction only to a minimal extent in a heterogeneous reaction. It is therefore extremely surprising that formoses or mixtures of formoses with the most varied of crystalline mono- and disaccharides can be mixed with dialkyl phosphites in any desired proportions, the addition of very small amounts of dialkyl phosphite noticeably reducing the viscosity of these mixtures causes. The addition of dialkyl phosphites and optionally also aminoplast monomers to formose or formose / mono- and / or disaccharide mixtures according to the invention also improves their emulsifiability or miscibility with the various low and high molecular weight polyhydroxyl compounds used in the production of polyurethane plastics .

und α-Hydroxyphosphonsäureestern der Konstitutionen

In the formoses modified with dialkyl phosphite according to the invention, depending on the formaldehyde content (which is present, for example, in the form of hemiacetals bound to the hydroxyl groups of the formose or in N-methylol groups of the aminoplast monomers) and the temperature position, equilibria are formed between the free dialkyl phosphite and hydroxymethanephosphonic acid esters of the constitution

and α-hydroxyphosphonic acid esters of the constitutions

At higher temperatures (above about 35 ° C) and especially in the presence of catalytic amounts of inorganic bases or, preferably, tertiary amines such as triethylamine or dimethylbenzylamine, these connections at reduced pressure surprisingly fast Lhüagerungsreaktionen and Umsterungsreakticnen do under ^{Alkoholabspal g} and there arise cyclic phosphites the formose or via intermolecular linkage of formoses of higher molecular weight polyphosphites or formose esters of hydroxymethylphosphonic acid. Depending on the amount of alcohol split off, any degree of transesterification can be achieved and thus, for example, viscosities from approx. 300 mPas at 20 ° C. to approx. 110,000 mPas at 20 ° C.

Preferably, one works at this subsequent chemical modification of the mixtures of the invention in a temperature range of 20 to 90 ⁰ C, particularly preferably from 25 to 65 ° C, and at pressures of 0.1 to 100 Torr, more preferably from 0.3 to 20 Torr . The modification reactions mentioned are explained in more detail in the examples.

Up to 150% by weight, preferably 10 to 100% by weight, of fillers such as, for example, can be incorporated into the mixtures according to the invention wise alumina hydrate are stirred in, forming stable, non-sedimenting, paste-like dispersions. These dispersions are ideal for the production of filler-containing polyurethane foams.

The mixtures according to the invention can also be used as flame retardants for plastics and textiles; they are also antifreeze agents with an anti-corrosive effect.

The mixtures according to the invention can be prepared by simply mixing the various starting components in any order. It is preferable to start with an optionally water-containing formose, to mix it with the aminoplast monomers and then to add any α-aldolized formoses, mono- and / or disaccharides that may be used, and to dewater the mixtures to a water content of 0.5-10%. , eg at reduced pressure and 30 - 60 ° C, and mixed with the dialkyl phosphite to clear solutions. After the condensation reaction has ended in the formose solution, residual formaldehyde still present, which is bound in a hemiacetal manner, preferably after dehydration to 0.5 to 4% of water, can be trapped by adding the dialkyl phosphite to form the corresponding hydroxymethylphosphonic acid esters. The additional mixture components which may also be used can then be added. Of course, it is also possible to add individual admixing components (aminoplast monomer; monosaccharides; disaccharides; other aldehydes and ketones) to the reaction mixture already during the synthesis of the formose and then to add the dialkyl phosphites, preferably after the mixtures have been dewatered to 0.5-10% water. The mixtures according to the invention can of course contain the aforementioned aldehydes and ketones, mono- or polyaldimines or ketimines, but also aldehydes and ketones together with mono- or polyamines, are subsequently admixed, hydroxyalkylphosphonic acid esters or alkyl- or polyamino-phosphonic acid alkyl esters being prepared in situ in the mixture according to the invention.

As already mentioned several times, the main use of the mixtures according to the invention is in the production of particularly flame-resistant polyurethane plastics, in particular polyurethane foams.

• a) Polyisocyanaten mit
• b) Polyhydroxylverbindungen mit einem Molekulargewicht unter 400, ggf.
• c) Polyhydroxylverbindungen mit einem Molekulargewicht zwischen 400 und 10.000 sowie ggf. weiteren gegenüber Isocyanat reaktiven Verbindungen, ggf. in Gegenwart von
• d) Treibmitteln, Katalysatoren, Füllstoffen und weiteren an sich bekannten Zusatzstoffen,

welches dadurch gekennzeichnet ist, daß als Kompomente b) die erfindungsgemäßen Gemische, welche gegebenenfalls durch die erwähnten Umesterungsreaktionen und Umlagerungsreaktionen modifiziert wurden, eingesetzt werden.The present invention thus also relates to a process for the production of possibly cellular polyurethane plastics by reacting

• a) with polyisocyanates
• b) polyhydroxyl compounds with a molecular weight below 400, if appropriate
• c) polyhydroxyl compounds with a molecular weight between 400 and 10,000 and optionally further compounds which are reactive toward isocyanate, optionally in the presence of
• d) blowing agents, catalysts, fillers and other additives known per se,

which is characterized in that the mixtures according to the invention, which have optionally been modified by the transesterification reactions and rearrangement reactions mentioned, are used as components b).

Since the mixtures according to the invention generally contain more or less large amounts of water (the water can only be completely removed from molding mixtures with a great deal of technical effort), are suitable the mixtures according to the invention in particular for the production of polyurethane foams. Depending on the recipe used, both open-cell and closed-cell rigid polyurethane foams and open-cell flexible foams can be produced according to the invention.

For the production of open-cell rigid foams, it is expedient to select formulations which contain between 4 and 25 percent by weight, particularly preferably between 8 and 20%, water. If appropriate, the suspensions of aluminum oxide hydrate or other mineral fillers described above can also be used in the mixtures according to the invention. If necessary, up to 100 parts by weight, preferably 10 to 50% by weight, based on the total polyol component, of a higher molecular weight polyhydroxy compound (molecular weight approx. 400-10,000) can also be used as an elasticizing component. The amount of polyisocyanate in the formulation can vary within wide limits; it is possible to use both an excess of polyisocyanate (up to 120 of the calculated equivalent amount) and a less than equivalent amount of polyisocyanate, calculated on the sum of the isocyanate-reactive components present. However, it was found that the lower the characteristic number of the formulation (equivalent ratio of polyisocyanates and compounds reactive toward isocyanates), the higher the flame resistance of the foams obtained in this way. It is therefore preferable to work in the range between 20 and 70, particularly preferably between 30 and 60, in particular between 35 and 55.

For the production of closed-cell rigid foams, preference is given to selecting mixtures according to the invention which contain 0 to 4 t, particularly preferably 0.7 to 3% by weight, of water. In this case, foaming is caused by the addition of low-boiling liquids such as eg fluorotrichloromethane. With regard to the key figure of the recipes, the same applies as has already been done for open-cell rigid foams.

However, the mixtures according to the invention can to 3 ₀ percent, in proportions of 5 -%, preferably 5 to 20 wt .-%, based on total polyol component, also be used as crosslinkers in the preparation of open-cell foams. The rest of the polyol component in this case consists of polyhydroxyl compounds with a molecular weight of 400 to 10,000, preferably of polyether polyols.

Aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, such as those described by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, are suitable as isocyanate components for the production of the optionally cellular polyurethane plastics. for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1.12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (DAS 1 202 785, American patent specification 3 401 190), 2,4- and 2,6-hexahydrotoluenediisocyanate and any 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 any mixtures of these isomers, diphenylmethane-2,4'- and / or -4,4'-diisocy anate, naphthylene-1,5-diisocyanate, triphenylmethane-4,4 ', 4 "-triisocyanate, polyphenylpolymethylene polyisocyanates as obtained by aniline-formaldehyde condensation and subsequent phoagenization and described, for example, in British Patents 874,430 and 848,671 are, m- and p-isocyanatophenylsulfonyl isocyanates according to the American patent 3,454,606, perchlorinated aryl polyisocyanates, such as, for example German Patent Specification 1 157 60 "(US Pat. No. 3,277,138) describes polyisocyanates containing carbodiimide groups, as described in German Patent 1,092,007 (US Pat. No. 3,152,162), diisocyanates as described in American Patent 3 492,330, polyisocyanates containing allophanate groups, as described, for example, in British patent specification 994 89 ₀ , Belgian patent specification 761 626 and published Dutch patent application 7 102 524, polyisocyanates containing isocyanurate groups, as described, for example, in American patent specification 3 001 973 , in the German patents 1 022 789, 1 222 067 and 1 027 394 and in the German laid-open publications 1 929 034 and 2 004 048, polyisocyanates containing urethane groups, as described, for example, in the Belgian patent specification 752 261 or in the American patent specification 3 394,164, acyli First polyisocyanates containing urea groups according to German Patent 1,230,778, polyisocyanates having biuret groups, as described, for example, in German Patent 1,101,394 (US Pat. Nos. 3,124,605 and 3,201,372) and in British Patent 889,050, were produced by telomerization reactions Polyisocyanates as described, for example, in US Pat. No. 3,654,106, polyisocyanates containing ester groups, as mentioned, for example, in British Pat. Nos. 965,474 and 1,072,956, in American Pat. No. 3,567,763 and in German Pat. No. 1,231,688 , Reaction products of the above isocyanates with acetals according to the German patent 1,072,385 and polyisocyanates containing polymeric fatty acid residues according to the American patent specification 3,455,883.

It is also possible to use the distillation residues obtained in the industrial production of isocyanates and containing isocyanate groups, optionally dissolved in one or more of the aforementioned polyisocyanates. It is also possible to use any mixtures of the aforementioned polyisocyanates.

The technically easily accessible polyisocyanates, e.g. 2,4- and 2,6-tolylene diisocyanate as well as any mixtures of these isomers ("TDI"), polyphenyJ-polymethylene polylsocyanates, such as those produced by aniline-formaldehyde condensation and subsequent phosgenation ("crude MDI") and carbodiimide groups, Urethane groups, allophanate groups, isocyanurate groups, urea groups of the polyisocyanates containing biuret groups ("modified polyisocyanates").

Suitable higher molecular weight polyhydroxyl compounds, especially those with a molecular weight of 800 to 10,000, preferably 1000 to 6000, are e.g. at least two, usually 2 to 8, but preferably 2 to 4, hydroxyl-containing polyesters, polyethers, polythioethers, polyacetals, polycarbonates and polyesteramides, as are known per se for the production of homogeneous and cellular polyurethanes.

The polyesters containing hydroxyl groups are, for example, reaction products of polyhydric, preferably dihydric and optionally additionally trihydric alcohols with polyhydric, preferably dihydric, carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic acid can also be used anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof can be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic and / or heterocyclic in nature and optionally substituted, for example by halogen atoms, and / or unsaturated.

Examples of these are: succinic acid, adipic acid, azelaic acid, phthalic acid, trimellitic acid, Phthalsäurcanhydrid, tetrahydrophthalic anhydride, tetrachlorophthalic endomethylenetetrahydrophthalic, glutaric anhydride, maleic anhydride, fumaric acid, dimeric and trimeric fatty acids such as oleic acid, optionally mixed with monomeric fatty acids, dimethyl terephthalate and bis-glycol terephthalate. Polyhydric alcohols include, for example, ethylene glycol, propylene glycol (1,2) and - (1,3), butylene glycol (1,4) and - (2,3), hexanediol (1,6), octanediol (1, 8), neopentyl glycol, cyclohexanedimethanol (1,4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propanediol, glycerin, trimethylolpropane, hexanetriol- (1,2,6), butanetriol- (1,2,4 ), trimethylolethane, pentaerythritol, quinitol, mannitol and sorbitol, methyl glycoside, also diethylene glycol, triethylene glycol, _T etraäthylenglykol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycols. The polyesters can have a proportion of terminal carboxyl groups. Lactone polyesters, for example e-caprolactone or hydroxycarboxylic acids, _{e.g. B.} ω-hydroxycaproic acid can be used.

Also according to the invention in question, at least two, generally two to eight, preferably two to three, hydroxyl-containing polyethers are those of the type known per se and are, for example, by _P oly- merization of epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with themselves, for example in the presence of BF ₃ , or by addition of these epoxides, optionally in a mixture or in succession, to starting components with reactive hydrogen atoms such as water, alcohols, ammonia or Amines, for example ethylene glycol, propylene glycol (1,3) or - (1,2), trimethylolpropane, 4,4'-dihydroxy-diphenylpropane, aniline, ethanolamine or ethylenediamine. Sucrose polyethers, such as are described, for example, in German publications 1 176 358 and 1 064 938, are also suitable according to the invention. In many cases, those polyethers are preferred which predominantly (up to 90% by weight, based on all the OH groups present in the polyether) have primary OH groups. Polyethers modified by vinyl polymers, such as those formed, for example, by polymerizing styrene and acrylonitrile in the presence of polyethers (American patents 3,383,351, 3,304,273, 3,523,093, 3,110,695, German patent 1,152,536), are also suitable Polybutadienes containing OH groups.

Among the polythioethers, the condensation products of thiodiglycol with itself and / or with other glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or amino alcohols may be mentioned. Depending on the co-components, the products are either polythio ether, polythioether or polythioether amide.

As polyacetals e.g. the compounds which can be prepared from glycols, such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxydiphenyldimethylmethane, hexanediol and formaldehyde, are suitable. Polyacetals suitable according to the invention can also be prepared by polymerizing cyclic acetals.

Suitable polycarbonates containing hydroxyl groups are those of the type known per se, which e.g. by reacting diols such as propanediol (1,3), butanediol (1,4) and / or hexanediol (1,6), diethylene glycol, triethylene glycol or tetraethylene glycol with diaryl carbonates, e.g. Diphenyl carbonate, or phosgene can be produced.

The polyester amides and polyamides include e.g. the predominantly linear condensates obtained from polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and their mixtures.

Polyhydroxyl compounds already containing urethane or urea groups and optionally modified natural polyols such as castor oil, carbohydrates or starch can also be used. Addition products of alkylene oxides on phenol-formaldehyde resin or also on urea-formaldehyde resins can also be used according to the invention.

Representatives of these compounds to be used according to the invention are e.g. in High Polymers, Vol. XVI, "Polyurethanes, Chemistry and Technology", written by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32-42 and pages 44-54 and Volume II, 1964, Pages 5-6 and 198-199, as well as in the plastics manual, volume VII, Vieweg-Höchtlen, Carl-Hanser-Verlag, Munich, 1966, e.g. on pages 45-71.

Of course, mixtures of the above-mentioned compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight of 400-10,000, e.g. Mixtures of polyethers and polyesters can be used.

Compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight of 32-400 can also be used as starting components which may be used according to the invention. In this case too, this means hydroxyl groups and / or amino groups and / or thiol groups and / or carboxyl groups, preferably compounds having hydroxyl groups and / or amino groups, which serve as chain extenders or crosslinking agents. These compounds generally have 2 to 8 isocyanate-reactive hydrogen atoms, preferably 2 or 3 reactive hydrogen atoms.

Examples of such compounds are: ethylene glycol, (1,2) and - (1,3) propylene glycol, (1,4) and - (2,3) butylene glycol, (1,5) pentanediol, hexanediol (1,6), octanediol- (1,8), neopentyl glycol, 1,4-bishydroxymethyl-cyclohexane, 2-methyl-1,3-propanediol, glycerin, trimethylolpropane, hexanetriol- (1,2,6), trimethylolethane, Pentaerythritol, quinite, mannitol and sorbitol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols with a molecular weight of up to 400, dipropylene glycol, polypropylene glycols with a molecular weight of up to 400, dibutylene glycol, polybutylene glycols with a molecular weight of up to 400, 4,4'-propylene-dihydroxy hydroquinone, ethanolamine, diethanolamine, triethanolamine, 3-aminopropanol, ethylenediamine, 1,3-diaminopropane, 1-mercapto-3-aminopropane, 4-hydroxy- or aminophthalic acid, succinic acid, adipic acid, hydrazine, N, N ' -Dimethylhydrazine, 4,4'-diaminodiphenylmethane, toluenediamine, methylene-bis-chloroaniline, methylene-bis-anthrani oleic acid ester diaminobenzoic acid ester and the isomeric chlorophenylene diamines.

In this case too, mixtures of different compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight of 32-400 can be used.

According to the invention, however, polyhydroxyl compounds can also be used in which high molecular weight polyadducts or polycondensates are contained in finely diaphanous or dissolved form. Such modified polyhydroxyl compounds are obtained if polyaddition reactions (e.g. reactions between polyisocyanates and amino-functional compounds) or polycondensation reactions (e.g. between formaldehyde and phenols and / or amines) are carried out directly in situ in the above-mentioned compounds containing hydroxyl groups. Such methods are described, for example, in German Auslegeschrift 1 168 075 and 1 260 142, and German Offenlegungsschriften 2,324,134, 2,423,984, 2,512,385, 2,513,815, 2,550,796, 2,550,797, 2,550,833 and 2,550 862. However, it is also possible to mix a finished aqueous polymer dispersion with a polyhydroxyl compound in accordance with US Pat. No. 3,869,413 or German Offenlegungsschrift 2,550,860 and then remove the water from the mixture.

When using modified polyhydroxyl compounds of the type mentioned above as the starting component in the polyisocyanate polyaddition process, polyurethane plastics with significantly improved mechanical properties are produced in many cases.

The exclusive reaction of water-free mixtures according to the invention (without the use of other components which are reactive toward isocyanates) with highly elasticizing polyisocyanates, e.g. Polyisocyanates with a biuret structure (DAS 1 543 178) result in hard, scratch and solvent resistant coatings and varnishes.

in welchem

• D für einen zweiwertigen Rest steht, wie er durch Entfernung der beiden Isocyanatgruppen aus einem Diisocyanat entsteht.

An advantage of the mixtures according to the invention in the reaction with polyisocyanates is that all mixture components take part in the polyisocyanate polyaddition reaction and are incorporated into the polyurethane, so that no solvents are released into the environment. Excess, non-esterified dialkyl phosphite also reacts with polyisocyanates, for example according to the formula scheme below

in which

• D stands for a divalent radical as it is formed by removing the two isocyanate groups from a diisocyanate.

The flame resistance of the plastics obtained is substantially increased by the phosphorus built into the polyurethane in this way or by reaction of polyisocyanates with α-hydroxyalkylphosphonic acid esters or α-aminoalkylphosphonic acid esters. Another improvement in Flame resistance is achieved by the additional use of aminoplast monomers in the mixtures according to the invention.

The following examples illustrate the present invention. Unless otherwise noted, quantities are to be understood as parts by weight or percentages by weight.

example 1

• a) Man mischt bei 45°C 175,9 g der 5,6 % Wasser enthaltenden Formose (1 Mol Formose) mit 138 g Diäthylphosphit (1 Mol) und erhält eine klare, gelblich gefärbte Lösung mit einer Viskosität von nur 273 mPas bei 25°C und einem Wassergehalt von ca. 3,1 %.
• b) Man mischt bei 45°C 179,9 g der Formose mit 110 g Dimethylphosphit (1 Mol) und erhält eine Lösung mit einer Viskosität von lediglich 174 mPas bei 25°C und einem Wassergehalt von ca. 3,4 %.

The formose used in this example was prepared according to Example 1 of DOS 2 639 084. The formose has an average OH functionality of 4.68, an average molecular weight of 166 and a viscosity of 24,500 mPas / 50 ° C. at a water content of 5.6%. At 25 ° C the viscosity can no longer be measured; it is over 550,000 mPas.

• a) 175.9 g of the 5.6% water-containing formose (1 mol of formose) are mixed with 138 g of diethyl phosphite (1 mol) at 45 ° C. and a clear, yellowish-colored solution with a viscosity of only 273 mPas at 25 is obtained ° C and a water content of approx. 3.1%.
• b) 179.9 g of the formose are mixed with 110 g of dimethyl phosphite (1 mol) at 45 ° C. and a solution is obtained with a viscosity of only 174 mPas at 25 ° C. and a water content of approx. 3.4%.

Both mixtures a) and b) do not tend to sedimentation of higher molecular sugars even at 0 ° C.

At room temperature and pH 7, the mixtures a) and b) according to the invention are stable on storage, as is shown by the constant viscosity. Under the influence of catalytic amounts of acids or bases (eg triethylamine, dimethylbenzylamine or endoethylene piperazine), the dimethyl phosphite or diethyl phosphite is added to the carbonyl groups of the formose to form the corresponding α-hydroxyphosphonic acid esters and transesterification reactions occur with Ab cleavage of methyl or ethyl alcohol, through which phosphites form the sugar. The transesterification reactions can be completed quantitatively by applying a vacuum and heating (for example 14 Torr and 55 ° C).

in welcher

• X für eine ganze Zahl von 0 bis 6 und
• R für Methyl bzw. Äthyl stehen.

Since the primary hydroxyl groups are more easily transesterified than the secondary ones, essentially products of the idealized formula are ultimately obtained

in which

• X for an integer from 0 to 6 and
• R represents methyl or ethyl.

über. Infolge von Dehydratisierungsreaktionen der freien Hydroxylgruppen der Zucker werden im Verlaufe steigender Umesterungsgrade cognakfarbene bis braune Endprodukte erhalten.The viscosity of these monoesters is 34,000 mPas at 25 ° C. Under more vigorous transesterification conditions, these phosphite esters split off further amounts of alcohols and go into highly viscous, gel-like, partially crosslinked sugar polyphosphites, for example those of the idealized formula

over. As a result of dehydration reactions of the free hydroxyl groups of the sugars increase in the course Obtain transesterification levels of cognac-colored to brown end products.

Example 2

This example shows that an increased supply of dialkyl phosphite can be used to obtain almost water-thin solutions which, if desired, can later be converted at any time into formose phosphite esters with a defined degree of esterification.

175.9 g of the formose used in Example 1 with a water content of 5.6% are mixed at 48 ° C. with 484 g of dimethyl phosphite (4.4 mol). The clear, slightly yellowish solution obtained has the surprisingly low viscosity of only 9 mPas at 25 ° C.

At any point in time, 100.8 g of methanol (3.15 mol) and 11 g of dimethyl phosphite can be distilled off from this reactive solution at 60 ° C. and 18 torr in the course of 10 hours. On average, 3.18 OH equivalents of 4.68 esterifiable OH equivalents of the formose used were then esterified. Here, the viscosity of the solution (because of the high degree of transesterification) increases significantly less than in Example 1, namely only to 131 mPas / 25 ° C.

By using 5 to 8 moles of dimethyl phosphite or diethyl phosphite per mole of the formose, the hydroxyl groups present can be esterified almost quantitatively, essentially asymmetric formose phosphite esters, e.g.

erhalten werden. Bei diesem maximalen Veresterungsgrad und den erforderlichen langen Kondensationszeiten von 11 bis 18 Stunden verfärben sich auch hierbei infolge von Dehydratisierungsreaktionen der freien Hydroxylgruppen der Zucker die Endprodukte über cognakfarbene zu braunen niederviskosen Lösungen.those of the idealized constitution

be preserved. With this maximum degree of esterification and the required long condensation times of 11 to 18 hours, the end products also change color here due to dehydration reactions of the free hydroxyl groups of the sugars via cognac-colored to brown, low-viscosity solutions.

Example 3

This example shows that α-aldolized formose with diethyl phosphite or dimethyl phosphite also gives very low-viscosity mixtures.

a) Preparation of the α-aldolized formose:

500 g of a fully desalted, 50% by weight formose-containing aqueous solution which was prepared according to Example 1 of DOS 2 639 084 (250 g formose solid; average molecular weight approx. 168; approx. 1.49 mol) are mixed with 149 g a 30% formalin solution (approx. 1.49 mol) and 10 g of triethylamine. The mixture is heated to 85 ° C. with stirring and the decrease in formaldehyde is followed by titration with sodium sulfite. The shape is already after 45 minutes Aldehyde content in the solution dropped from 6.3% to 0.5% and the α-aldolization ended. The hot solution is clarified by adding 8 g of activated carbon, filtered and a slightly yellowish-colored solution is obtained in which there are predominantly α-methylolated formoses of the following idealized constitutions:

The targeted α-aldolization formoses be obtained which contain primary per molecule on average at least two hydroxyl groups and, therefore, isocyanates over _P oly- have a higher reactivity than the Ausgangsformosen.

Surprisingly, the α - aldolization is strongly preferred over possible crossed Cannizzaro reactions with this method of operation: as can be concluded from the analytically determined amount of formations, only about 3 g of the formaldehyde used (approx. 7% of the total amount) undergo crossed Cannizzaro reactions.

The viscosity of the aldolized formose thus produced, which was concentrated to a water content of 5.2 in a rotary evaporator, is not measurable either at 25 ° C. or 35 ° C. and is above 570,000 mPas. At 50 ° C the viscosity of the formose is 25 736 mPas. The average molecular weight of this α-aldolized formose is approximately 198.

If 198 a of the α-aldolized formose (1 mol of formose solid) are mixed with 138 g of diethyl phosphite (1 mol) at 50 ° C., a clear, yellowish-colored solution is obtained which at 25 ° C. only has a viscosity of 576 mPas.

Example 4

241 g of a mixture of 1 mol of the formose according to Example 1 of DOS 2 639 084, 1.12 mol of urea and 0.5 mol of water, which was prepared by simply mixing the components and dewatering in a rotary evaporator at 15 torr and 55 ° C. and which has a viscosity of 81,000 mPas at 35 ° C, are converted by adding 204 g (1.48 mol) of diethyl phosphite into a completely clear solution which has a viscosity of only 127 mPas at 35 ° C.

Example 5

_M in the same process as in Example 4 but replacing the urea by 1.12 _M ol ε-caprolactam. The solution obtained has a viscosity of only 27 mPas at 35 ° C.

Example 6

• a) 614 g einer Mischung aus 1,5 Mol Formose des Beispiel 1, 2 Mol Monomethylolthioharnstoff und 2,7 Mol Wasser, die durch einfache Mischung der Komponenten in 50 %iger wäßriger Lösung und Entwässerung im Rotationsverdampfer bei 55°C und 15 Torr erhalten wurde (Viskosität bei 25°C und einem Wassergehalt von 8 %: 2413 mPas) werden mit 690 g (5 Mol) Diäthylphosphit bei Raumtemperatur vermischt. Man erhält ein erfindungsgemäßes Gemisch, das bei 25°C lediglich eine Viskosität von 600 mPas aufweist.
• b) Man verfährt wie bei a), ersetzt den Monomethylolthioharnstoff aber durch 270 g ( 3 Mol) an Monomethylolharnstoff. Die Viskosität der Formose-Aminoplastmonomer-Lösung beträgt 72 633 mPas/25°C,nach Modifizierung mit Diäthylphosphit 300 mPas bei 25°C.
• c) Man mischt wie bei a) 1,5 Mol Formose mit 2 Mol N-Methylolcaprolactam und C,57 Mol Wasser. Das Gemisch hat bei 25°C eine Viskosität von 17 305 mPas. Durch Abmischen von 687 g dieser Formose-Aminoplastmonomer-Mischung mit 690 g Diäthylphosphit erhält man eine erfindungsgemäße Mischung mit einer Viskosität von 120 mPas bei 25°C.

This example describes the preparation of a further type of mixtures according to the invention in which N-methylol compounds of thiourea, urea or ε-caprolactam are present in solution.

• a) 614 g of a mixture of 1.5 mol of formose from Example 1, 2 mol of monomethylolthiourea and 2.7 mol of water, which are obtained by simply mixing the components in 50% strength aqueous solution and dewatering in a rotary evaporator at 55 ° C. and 15 torr (viscosity at 25 ° C and a water content of 8%: 2413 mPas) are mixed with 690 g (5 mol) of diethyl phosphite at room temperature. A mixture according to the invention is obtained which has a viscosity of only 600 mPas at 25 ° C.
• b) The procedure is as in a), but the monomethylol thiourea is replaced by 270 g (3 mol) of monomethylol urea. The viscosity of the formose aminoplast monomer solution is 72 633 mPas / 25 ° C, after modification with diethyl phosphite 300 mPas at 25 ° C.
• c) Mix as in a) 1.5 mol of formose with 2 mol of N-methylolcaprolactam and C, 57 mol of water. The mixture has a viscosity of 17,305 mPas at 25 ° C. Mixing 687 g of this formose-aminoplast monomer mixture with 690 g of diethyl phosphite gives a mixture according to the invention with a viscosity of 120 mPas at 25 ° C.

kondensieren.Mixtures a), b) and c) are reactive solutions which are not at 50 to 70 ° C in a vacuum of 1 to 15 torr easy only ethanol elimination respond to Formose phosphite esters but also with the aminoplast on dehydration _A midophosphonsäureestern such as

condense.

If formoses are used in the preparation of solutions of the type mentioned under a) to c), which contain formaldehyde bound in hemiacetal form, hydroxymethanephosphonic acid diethyl ester, which is capable of analogous condensation reactions as diethylphosphite, forms almost quantitatively from split-off formaldehyde and diethyl phosphite.

Example 7

und 298 g Diäthylphosphit zu einer 50 %igen erfindungsgemäßen Mischung. Die erhaltene Lösung hat eine erstaunlich geringe Viskosität von nur 230 mPas bei 25°C.166 g of the formose described in Example 1 are mixed with 132 g (1 mol)

and 298 g of diethyl phosphite to form a 50% mixture according to the invention. The solution obtained has an astonishingly low viscosity of only 230 mPas at 25 ° C.

Example 8

This example shows that almost completely ent aqueous formoses, with a water content of approx. 0.7%, dissolve in diethyl phosphite or dimethyl phosphite to give mixtures according to the invention with a greatly reduced viscosity:

The formose described in Example 1 is dissolved in diethyl phosphite in various concentrations at 50 ° C. The following viscosity concentration dependency is found:

Example 9

This example shows the technically particularly interesting possible use of the mixtures according to the invention for the production of extremely flame-retardant, open-pore, strongly carbonizing rigid polyurea-polyurethane foams in the range 45 to 50, i.e. with insufficient amounts of polyisocyanates.

(der Zahlenmittelwert von x beträgt 20).a) 88 parts by weight of the mixture described in Example 6 b) at 35 ° C with 40 parts of a _G-ew. started on trimethylolpropane propylene oxide-ethylene oxide ether Mischpoly- an OH number of 28 as _El astifizierungsmittel d- ent, mixed. The polyether contains 0.7 part by weight of an emulsifier of the constitution

(the number average of x is 20).

The intensely stirred mixture is mixed with 3 parts by weight of water, 1.2 parts by weight of a commercially available silicone stabilizer (stabilizer OS 610 from Bayer AG), 0.2 part by weight of endoethylene piperazine and 0.25 part by weight of tin -II-octoate was added and then 184 parts by weight of a phosgenation product of an industrial aniline-formaldehyde condensate were stirred in. The polyisocyanate used has an NCO content of 29%. Foam formation is complete after 6 minutes and with a very even rise time without any signs of shrinkage. An open-cell rigid foam with a built-in flame retardant is obtained, which has a density of 30 kg / m.

Cut rigid foam strips with a width of 1 cm, a thickness of 1 cm and a length of 10 cm cannot be ignited when exposed to a Bunsen flame, so the flame's running speed is zero. Flaming the strip with the Bunsen flame for more than 30 seconds also means that no flame propagation can be achieved; the fire process only manifests itself in carbonization of the foam and in the elimination of water-rich fire gases.

b) The procedure is as described under a), but 5 parts by weight of a mixture consisting of formose and N-methylolcaprolactam (1: 1) are added, as a result of which the reaction between NCO groups and water is strongly activated and the fluidity of the system is prolonged becomes. A rigid foam with excellent flame retardancy and a density of 26 kg / m ^{3 is obtained} .

c) If the mixture according to the invention described in Example 6 b) is used for impregnation reactions or matrix reactions in flexible polyurethane foams, even before the modification, flammable flexible polyurethane foams become so flame-retardant that they self-extinguish after ignition with a Bunsen flame.

Claims (11)

1) A method for lowering the viscosity of formose or mixtures of formose and _M ONO and / or disaccharides by addition of a viscosity reducing agent, characterized in that as a viscosity-lowering agent dialkylphosphites used. 2) Mixtures reactive towards isocyanates, consisting of A) 3 to 97 parts by weight, based on the Sunme of components A, B and C, of formose and optionally mono- and / or disaccharides, B) 3 to 97% by weight, based on the sum of components A, B and C, of dialkyl phosphites and optionally trialkyl phosphites and / or α-hydroxyalkylphosphonic acid esters and / or α-aminoalkylphosphonic acid esters and C) 0 to 10% by weight, based on the sum of components A, B and C, of water. 3) Mixtures according to claim 2, characterized in that they consist of 10 to 95 wt .-% of component A, 5 to 90 wt .-% of component B and 0.3 to 6 wt .-% water. 4) Mixtures according to claim 2, characterized in that they consist of 30 to 80 wt .-% of component A, 15 to 60 wt .-% of component B and 0.3 to 6 wt .-% water. 5) Mixtures according to claim 2 to 4, characterized in that they consist of 1 mole of component A, 0.2 to 20 moles of component B and 0 to 3 moles of water. 6) Mixtures according to claim 2 to 4, characterized in that they consist of 1 mole of component A, 0.7 to 5 moles of component B and O to 1.5 moles of water. 7) Mixtures according to claim 2 to 6, characterized in that they contain up to 100 wt .-%, based on the sum of components A, B and C, of compounds capable of aminoplast formation or their N-methylol derivatives. 8) Mixtures according to claim 7, characterized in that they contain 10 to 50 wt .-% of the substance capable of aminoplast formation. 9) Process for the production of optionally cellular polyurethane plastics by reacting a) with polyisocyanates b) polyhydroxyl compounds with a molecular weight below 400, if appropriate c) polyhydroxyl compounds with a molecular weight between 400 and 10,000 and optionally further compounds which are reactive toward isocyanates, optionally in the presence of d) blowing agents, catalysts, fillers and other additives known per se,
characterized in that mixtures b) which have been modified by transesterification reactions, as claimed in claims 2 to 8, are used as component b). 10. A process for the preparation of photophorigeic esters of formose and optionally mono- and / or disaccharides, characterized in that the mixtures according to claims 1 to 8 are transesterified with removal of the alcohol component of the dialkyl phosphite. 11. The method according to claim 10, characterized in that the alcohol is removed at a temperature between 25 and 65 ° C with the application of a vacuum of 0.3 to 20 torr.