MXPA99002473A - Transparent polynocyanate polyadyanate products, compac - Google Patents

Abstract

Polyisocyanate products, transparent, compact polyisocyanates are produced in a process by reaction of: (a) isocyanates, with (b) compounds reactive to the isocyanates, if desired in the presence of (c) catalysts and (d) auxiliaries and / or additives, which consists in using as the isocyanate-reactive compounds (b) a mixture (i) having an average functionality of > 3 and an average hydroxyl index from 300 to 950 mg of KOH

Description

POLIADRIOÓSTST PRODUCTS? TRANSPARENT POLYISOCIANATES, COMPACT The invention relates to processes for producing polyaddition products of transparent, compact polyisocyanates by reaction of (a) isocyanates with (b) compounds reactive to isocyanates, if desired in the presence of (c) catalysts and (d) auxiliaries and / or additives. The invention also relates to polyaddition products of transparent, compact polyisocyanates that can be produced by this process, and to their use. The polyaddition products of compact polyisocyanates, also called products in the following, and their production are well known and have been described many times in the technical literature. These products are increasingly used in markets in which it is used for the preparation of glass, for example, for windows or covers for lamps in the construction of buildings, automobiles or airplanes. A particular advantage of plastics compared to glasses is their low density and low fragility, making it possible to save fuel and reduce the formation of chips when accidents occur. WO 96/23827, for example 7 discloses compact transparent polyurethanes for the production of windows for buildings, automobiles or aircraft. The products of WO 96/23827 are produced by reaction of cycloaliphatic isocyanates with bifunctional polyols to give an NCO-terminated prepolymer, followed by the reaction between polymer with a diamine. The disadvantage of these products is their relatively low shore hardness D 80-81 and their large coefficient of thermal expansion. However, a high level of hardness and a low coefficient of thermal expansion are precisely what is required, in particular in the construction of automobiles and aircraft, for example, to avoid damage to products by scratches. It is an object of the present invention to develop a process for the production of polyaddition products of transparent, compact polyisocyanates by reaction of (a) isocyanates with (b) compounds reactive to the isocyanates, if desired in the presence of (c) catalysts and ( d) auxiliaries and / or additives, which is capable of producing products that are very suitable for replacing glass. These products must have, in particular, a high level of hardness and a low coefficient of thermal expansion. We have found that this objective is carried out by using as compounds reactive to the isocyanates (b) a mixture (i) having an average functionality of > 3 and an average hydroxyl number from 300 to 950 mg KOH / g. According to the invention, the high average functionality, ie the functions that are reactive to isocyanates, of the mixture and its high average hydroxyl number, also called OHI below, achieve strong crosslinking with "isocyanates in the products This gives the high level of hardness expected, and thus resistance to scratches of the products.In addition to this, the crosslinking gives the products the desired low coefficient of thermal expansion, measured in accordance with DIN 53752 (method A, with continuous heating.) The mixture (i) preferably has an average functionality from 3 to 6, particularly preferably from 3.1 to about 5. The OHI average of the mixture (i) is preferably from 400 to 900 mg KOH / g, in particular from 500 to 850 mg KOH / g. The use in this text of the expression mixtures does not imply that the compounds present there are necessarily in the form of a mixture when contacted with isocyanates, but simply define the material having the average functionalities and hydroxyl numbers according to the invention. The mixture (i) used to produce the polyisocyanate products of transparent, compact polyisocyanates is preferably one having an average functionality of > 3 and an average idroxyl index from 300 nasta 950 mg KOH / g and contains the following components: from 45 to 99% by weight of the mixture (ii) comprising at least one polyether polyalcohol, wherein - the mixture (ii) has an average functionality of at least 3, preferably from 3.1 to 6, and an average hydroxyl number from 650 to 950 mg KOH / g, preferably from 700 to 940 mg KOH / g , and from 1 to 55% by weight of a mixture (iii) comprising at least one polyalcohol polyester, wherein the mixture (iii) has an average functionality from 2 to 3 and an average hydroxyl number from 20 to 200 mg KOH / g. The polyether polyalcohols present in the mixture (ii) according to the invention can be well-known compounds which are produced by known processes, for example by alkoxylation of starting materials with alkylene oxides. The preparation can be carried out as an anionic polymerization with alkali metal hydroxides as catalysts, such as sodium hydroxide or potassium hydroxide or with alkali metal alcoholates, such as sodium methylate, sodium ethylate, potassium ethylate or sodium isopropylate. potassium, and with the addition of at least one initiator molecule containing from 2 to 8 reactive hydrogen atoms, preferably from 2 to 6 reactive hydrogen atoms, or as a cationic polymerization with Lewis acids as catalysts, such as pentachloride antimony, boron fluoroetherate, etc., or bleaching earths, with one or more alkylene oxides having from 2 to 4 carbon atoms in the alkylene radical. The catalyst is usually removed after synthesis by acid neutralization, distillation and filtration. The acids used are mainly the two mineral acids, hydrochloric acid and / or phosphoric acid, because the point of equivalence can be controlled with precision and the technology to remove any surplus is simple.

Examples of suitable alkylene oxide acids for the preparation of polyols are tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and 1-oxide. 2-propylene. The alkylene oxides can be used individually, alternately in succession or as mixtures. Preference is given to the use of alkylene oxides that produce primary hydroxyl groups in the polyol. Particular preference is given to the use of polyols which, to complete the alkoxylation, have been alkoxylated with ethylene oxide, and therefore have primary hydroxyl groups. Examples of initiator molecules are: water, organic dicarboxylic acids, such as succinic acid, adipic acid, phthalic acid, and terephthalic acid, aliphatic and aromatic diamines having from 1 to 4 carbon atoms in the alkyl radical and are substituted or N-mono - or N, N- or N, N '-dialkyl substituted, such as unsubstituted ethylenediamine, or if desired mono- or dialkyl substituted, diethylenetriamine, triethylenetetraamine, 1,3-propylenediamine, 1,3- or 1, 4- butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- or 1,6-hexamethylenediamine, phenylenediamine, 2,3-, 2,4- or 2,6-toluylenediamine and 4,4 ' -, 2,4'- and 2,2'-diamino diphenyl methane. Other possible starter molecules are: alkanolamines, such as ethanolamine, N-methyl- and N-ethylethanolamine, dialkanolamines, such as diethanolamine, N-methyl- and N-ethyldiethanolamine, and trialkanolamines such as triethanolamine, and ammonia, and also polyhydric alcohols, such as ethanediol, 1,2-propanediol, 1,3-propanediol, diethylene glycol, dipropylene glycol, 1-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitol and sucrose. To achieve the average functionality according to the invention, it is preferable to make use of initiator molecules having a functionality of at least 3. It is possible to include in the mixture (ii) polyether polyols with a lower functionality, but in this case at least a more highly functionalized polyether polyol should be present in the mixture (ii) in amounts such that the average functionalities reach a value according to the invention. The preferred polyether polyols used in the mixture (ii) are addition products of ethylene oxide and / or propylene oxide for glycerol, trimethylol propane, ethylenediamine and / or pentaerythritol individually or in mixtures.

The polyether polyalcohols present in the mixture (iii) according to the invention can be well-known compounds which are prepared by known processes. Suitable polyester polyols can, for example, be prepared from organic dicarboxylic acids having from 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids having from 2 to 6 carbon atoms, and polyhydric alcohols, preferably diols, having from 2 to 12 carbon atoms, preferably from 2 to 6 carbon atoms. Examples of possible dicarboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebasic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. These dicarboxylic acids can be used individually or in addition in a mixture with each other. Instead of the free dicarboxylic acids, it is also possible to use the corresponding dicarboxylic acid derivatives, such as esters of dicarboxylic acids with alcohols having from 1 to 4 carbon atoms or anhydrides of dicarboxylic acids. Examples of di- and polyhydric alcohols are: ethanediol, diethylene glycol, 1,2- and 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5- > pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, glycerol and trimethylolpropane. Preference is given to the use of ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerol and trimethylolpropane. It is also possible to use polyester polyols made from lactones, for example, e-caprolactone or hydroxycarboxylic acids, for example,? -hydroxycaproic acid.

In order to prepare the polyester polyols, the organic polycarboxylic acids, for example, aromatics and preferably aliphatics and / or polyhydric alcohols and derivatives can be polycondensed without catalysis or preferably in the presence of catalysts for esterification, useful in an atmosphere of inert gas, for example, nitrogen, carbon monoxide I, helium, argon, etc.; in the molten state from 150 to 200 ° C, preferably from 180 to 220 ° C, if desired under reduced pressure, up to the desired acid number, which is advantageously less than 10, Preferably less than 2. In a preferred embodiment, the esterification mixture is polycondensed to an acid number from 80 to 30, preferably from 40 to 30, under atmospheric pressure and then under a pressure of less than 500 mbar, preferably from 50 to 150 mbar. Examples of possible esterification catalysts are catalysts using iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium or tin, in the form of metals, metal oxides or metal salts. However, the polycondensation can be carried out in a liquid phase in the presence of diluents and / or carriers such as benzene, toluene, xylene or chlorobenzene for azeotropic removal of the condensation water by distillation. To prepare the polyester polyols, the organic polycarboxylic acids and / or their derivatives are polycondensed with polyhydric alcohols, advantageously in a molar ratio from 1: 1 to 1.8, preferably from 1: 1.05 to 1.2. The resulting polyester polyols preferably have a functionality of from 2 to 4, in particular from 2 to 3, and a hydroxyl number preferably from 20 to 200 mg KO? / G. In addition to the isocyanate-reactive compounds (b) mentioned as examples of mixtures (i), (ii) and (iii), other compounds (b) reactive to isocyanates, for example polythioether, can be used in the novel process. conventional polyols, polymer modified polyether polyols, preferably pre-grafted polyether polyols, in particular those based on styrene and / or acrylonitrile, polyether polyamines, polyacetals containing hydroxyl groups or aliphatic polycarbonates containing hydroxyl groups or mixtures of at least two of the mentioned polyols, which can be prepared by well processes > known. The compounds (b) reactive to the isocyanates can also be diols, triols and / or polyols with molecular weights < 400, for example, cycloaliphatic and / or araliphatic aliphatic diols having from 2 to 14 carbon atoms, preferably from 4 to 10 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,10-decanediol, or -, m- or p-dihydroxycyclohexane, diethylene glycol, ilO dipropylene glycol and preferably 1,4-butanediol, 1,6-hexanediol and bis (2-hydroxyethyl) -hydroquinone, triols, such as 1,2,4- and 1, 3, 5-trihydroxycyclohexane, glycerol and trimethylolpropane, and low molecular weight polyalkylene oxides containing hydroxyl and oxide-based groups ethylene and / or ZL oxide, 2-propylene and in the aforementioned diols and / or triols as initiator molecules. The compounds (b) reactive to the isocyanates and used in the novel process are particularly preferable compounds of the mixture (i) having an average functionality of > 3 and an average hydroxyl number from 300 to 950 mg KOH / g, which in turn are particularly preferably compounds of: from 45 to 99% by weight of a mixture (ii) comprising at least one polyether polyalcohol, wherein mix (Ii) has an average functionality of at least 3, preferably from 3.1 to 6, and an average hydroxyl number from 650 to 950 mg KOG / g [sic], preferably 700 to 940 mg KOH / g, and : from 1 to 55% by weight of a mixture (iii) comprising at least one polyester polyol, wherein the mixture (iii) has an average functionality from 2 to 3 and an average hydroxyl number from 20 to 200 mg KOH / g. > The possible isocyanates (a) are the aromatic, araliphatic, aliphatic and / or cycloaliphatic organic isocyanates known per se, preferably diisocyanates. The individual compounds that can be mentioned are: alkylene diisocyanates having from 4 to 12 carbon atoms in the alkylene radical, such as 1,2-dodecane diisocyanate, 1,4-ethylhetramethylene diisocyanate, 1,5-methylpentamethylene diisocyanate , 1, 4-tetramethylene diisocyanate, diisocyanate ester of Lysine (LDI) and 1,6-hexamethylene diisocyanate (HDI); cycloaliphatic diisocyanates, such as 1,3- and 1,4-cyclohexane diisocyanate, and also any desired mixture of these isomers, 2,4- and 2,6-hexahydrotoluene diisocyanate, and also the corresponding isomer mixtures, 4,4 '-, 2,2'- and 2,4'-diisocyanate dicyclohexylmethane, and also the corresponding isomeric mixtures, and l-isocyanato-3,3,3-dimethyl-5-isocyanatomethylcyclohexane (IPDI). Other examples of isocyanates (a) which can be mentioned are: 2-, 4- and 2,6-toluene diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2, 2'-diisocyanate of diphenylmethane and mixtures of corresponding isomers, mixtures of 4,4 '- and 2, 2' - diphenylmethane diisocyanates, polyphenylenepolymethylene polyisocyanates, mixtures of 4,4'-, 2, 2 '- diphenylmethane diisocyanates and polyphenylenepolymethylene polyisocyanates (Raw MDI) and mixtures of crude MDI and toluene diisocyanates. It is also possible to use mixtures containing at least two of the isocyanates mentioned as (a).

In the novel process it is possible to use di- and / or polyisocyanates containing isocyanates modified with isocyanurate groups, biuret groups, ester groups, urea groups, allophanate groups, carbodiimide groups, uretdione groups and / or urethane groups. The latter are also mentioned below modified with urethane group. Individual examples of these are: organic polyisocyanates containing urethane groups and containing NCO from 50 to 15% by weight, preferably from 35 to 21% by weight, based on the total weight, for example, with low weight diols molecular, triols, dialkylene glycols, trialkylene glycols or with polyoxyalkylene glycols having molecular weights of up to 6000, in particular having molecular weights up to 1500, mixtures of 4,4 'and ~ 274' - modified diphenylmethane diisocyanate, modified crude MDI or 2,4 - or 2,6-toluene diisocyanate. The di- and polyoxyalkylene glycols which can be mentioned as examples, and which can be used individually or as mixtures, are: diethylene and dipropylene glycol, and polyoxyethylene, polyoxypropylene and polyoxypropylene polyoxyethylene glycols, triols and / or tetraols. Other suitable materials are prepolymers containing NCO groups and have NCO contents of about 25 to 3.5% by weight, preferably 21 to 14% by weight, based on total weight, prepared from polyester polyols and / or preferably described polyether polyols and diphenylmethane 4,4'-diisocyanate, mixtures of 2,4 'and 4,4'-diphenylmethane diisocyanate and 2,4- and / or 2,6-toluene diisocyanates, or crude MDI. Other tested materials are liquid polyisocyanates containing carbodiimide groups and having NCO content from 33.6 to 15% by weight, preferably from 31 to 21% by weight, based on the total weight, and based on for example, 4.4%. -, 2,4'- and / or 2,2'-diphenylmethane diisocyanate and / or 2,4- and / or 2,6-toluene diisocyanate. The modified polyisocyanates can, if desired, be mixed with each other or with unmodified organic polyisocyanates, such as 2,4'- or 4,4'-diphenylmethane diisocyanate, crude MDI or 2,4- and / or 2, 6- toluene diisocyanate. The modified isocyanates used are preferably aliphatic and / or isocyanuratized cycloaliphatic diisocyanates, biuretized and / or modified by urethane groups, for example those already mentioned, which can be biuretized cyanuratized by the known processes and have at least one, preferably at least two free isocyanate groups, particularly preferably three free isocyanate groups. The trimerization of isocyanates to prepare the isocyanates are isocyanurate structure can be carried out at normal temperatures in the presence of known catalysts, for example, phosphines and / or phosphorin derivatives [sic], amines, alkali metal salts, metal compounds and / or Mannic bases. Trimerized isocyanates containing isocyanurate structures are also commercially available. Isocyanates with biuret structures can be prepared by well-known methods, for example, by reaction of the aforementioned diisocyanates with water or, for example, with diamines. The intermediate products produced in this case are urea derivatives. Biuretized isocyanates are also commercially available. Particularly preferred isocyanates (a) are aliphatic and / or cycloaliphatic diisocyanates, in particular 1,6-hexamethylene diisocyanate, the isomers of diisocyanate of dicyclohexyl methane and l-isocyanato-3,5,5-trimethyl-5-isocyanatomethylcyclohexane, which can, if desired, be isocyanurated, biuretized and / or modified by urethane groups. An advantage of aliphatic and / or cycloaliphatic isocyanates is that the products produced with these have better photo strength and little intrinsic color. The catalysts (c) used to produce the products may, if desired, be well-known compounds that markedly accelerate the reaction of the isocyanates with the compounds reactive to the isocyanates. The total catalyst content preferably used in this case is from 0 -.001 to 15% by weight, in particular from 0.05 to 6% by weight, based on the total weight used of the compounds (b) reactive to the isocyanates. Examples of possible catalysts (c) will now be mentioned: tertiary amines, such as triethylamine, tributylamine, trimethylbenzylamine, dicyclohexymethylamine, dimethylcyclohexylamine, N, N, N ', N' - tetramethyldiaminodiethylether, bis (dimethylaminopropyl) urea, N-methyl and N Ethylmorpholine, N-cyclohexylmorpholine, N, N, N ', N'-tetramethylethylenediamine, N,,', N '-tetramethylbutanediamine, N, N, N', N '-tetramethyl 1,6-hexandiamine, pentamethyldiethylenetriamine, dimethylpiperazine, N-dimethylaminoethylpiperidine, 1,8-diazabicyclo [5. .0] -7-undecene, 1,2-dimethyl imidazole, 1-azabicyclo [2.2.0] octane, 1,4-diazobicyclo [2.2.2] octane (Dabco), alkanolamine compounds, such as triethanolamine, triisopropanolamine, N-methyl - and N-ethyldiethanolamine, dimethylaminoethanol, 2- (N, N-dimethylaminoethoxy) ethanol, N, N'N "-tris- (dialkylaminoalkyl (hexahydrotriazines), such as N, N ', N" -tris- (dimethylaminopropyl) - s-hexahydrotriazine, and preferably triethylene diamine, pentamethyl diethylenetriamine and / or bis (dimethylaminoethyl) ether; metal salts, such as inorganic and / or organic iron, lead, zinc and / or tin compounds in the normal oxidation states of the metal, for example, iron (II) chloride, zinc chloride (lead octoate) and preferably tin salts, such as tin dioctate, tin diethylhexoate, dibutyltin dilaurate and / or dibutyldilauryl tin mercaptide.

Particularly preferred compounds such as (c) are dibutyl tin dilaurate, tin dioctoate and / or dibutyldilauryl tin mercaptide; amidines, such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, alkali metal hydroxides, such as sodium hydroxide and alkali metal alcoholates, such as sodium methoxide and isopropylate potassium, and also alkali metal salts of long chain fatty acids having from 10 to 20 carbon atoms and, if desired, side OH groups. The catalysts (c) mentioned as examples can be used individually or in mixtures containing at least two of the catalysts mentioned. The auxiliaries and / or additives (d) used, if desired, in the novel process can be usual substances, examples that can be mentioned are surface active substances, fillers, dyes, pigments, flame retardants, inhibitors of hydrolysis, substances with fungistatic or bacteriostatic action and also UV stabilizers and antioxidants, insofar as these do not damage the transparency of the products. This can be determined by means of simple routine experiments. It is also possible to use pigments and / or dyes in order to obtain dyed or colored moldings.

The use of antioxidants and UV stabilizers, in particular, may be advantageous in the novel process for many application sectors for the polyaddition products of transparent polyisocyanates, novel since the addition of these materials can prevent yellowing, discoloration or embrittlement of the products. Examples of UV stabilizers that can be used are the compounds mentioned in EP-A 712 887 on page 4, lines 10 to 20. Examples of antioxidants that can be used are the substances described in EP-A 712 887 on page 4 , lines 21 to 28. Examples of suitable pigments are also described in EP-A 712 887 on page 4, lines 29 to 37. To produce the novel products, isocyanates (a) and compounds (b) reactive to isocyanates they are reacted in amounts such that. the equivalence ratio of NCO groups of (a) to the total of the reactive hydrogen atoms of (b) is from 0.95 to 1.3: 1, preferably from 1 to 1.2: 1 and in particular from 1 to 1.15: 1. If there is at least one bound isocyanurate group present within the polyurethane molding, the ratio of the NCO groups used to the total of the reative hydrogen atoms is usually from 1.5 to 60: 1, preferably from 1.5 to 8: 1. The reaction according to the invention preferably takes place under very complete exclusion of water, and particularly preferably under total exclusion of water.

The products are usually produced by the process of a known step or by the prepolymer process, which is known in the same way. In a first step of the known prepolymer process, a prepolymer having isocyanate groups is usually prepared from (a) and an excess of (b). This is then reacted with more (b) to give the desired products. An advantage of the prepolymer process in the novel process is that the shrinkage could be reduced during the production of the product. In the one-step process, the components (a), (b) and, if desired, (c) and / or (d) are reacted to give the product in one step. It has proven advantageous in this case to operate by the two-component method and combine the components (b) and, if desired, the catalysts (c) and / or auxiliaries and / or additives (d) in component (A) and use the isocyanates (a) as component (B). The compounds reactive to the isocyanates and present according to the invention in mixtures (i), (ii) and (iii) can be introduced into the reaction mixture individually or also, preferably as in the two-component process, for example, in a mixture. The reaction to give the product follows the well-known processes, for example, hand casting, the use of high pressure or low pressure machine, or RIM (injection molding with reaction), in open or preferably closed molds, by example, metal molds. Suitable PU processing machines are commercially available (for example, from Elastogran, Isotherm, Hennecke, Kraus Maffei, etc.). It has proven advantageous that the components are devolatilized by application of reduced pressure (from 1 to 759 Torr) before processing, both of the molded parts obtained are free of bubbles.

It is also advantageous during processing with PU machines that the storage containers are at reduced pressure during processing. Depending on the application, the initial components are usually mixed from 0 to 100 ° C, preferably from 20 to 80 ° C, and introduced into the open mold, or if desired under superatmospheric pressure in the closed mold. The mixture can be carried out mechanically using an agitator or a screw mixer, or it can take place in a conventional high pressure mixing head. According to the invention, the reaction temperature in the mold, ie the temperature at which the reaction takes place, is > 40 ° C, preferably from 6Q to 100 ° C. After a period of 0.5 to 15 minutes, the reaction is usually completed sufficiently so that the product can be removed from the mold. The product is then preferably tempered from 100 to 160 ° C, preferably in a mold, to give the complete reaction of the isocyanate groups. With the novel process it is also possible to produce transparent outer layers that usually have a thickness of about 0.1 to 3 mm. These outer layers that can assume, for example, the function of a clear multilayer cover, for example, for surface protection, for example, dashboard parts for cars, are produced in the one-step process or the prepolymer, as It was described before. For this, the components are applied in an open or closed mold to the object to be protected by means of the product. If desired, the surface can be further improved by subsequent grinding or polishing. The products produced by the novel process usually have a density of about 0.95 to 1.20 g / cm. Polyisocyanate polyaddition products kl? transparent compact, obtained by the novel process can preferably be used as substitutes for glass, for example, in roofs for the sun, front windows, rear windows or side windows in the automotive or aircraft construction and / or as covers for 15 lamp , for example, _ as front lamps or rear lamps in the construction of aircraft or automobiles. Roofs for the sun, front windows, rear windows or side windows under construction of cars or airplanes or covers for lamps containing the novel products polyaddition of transparent, compact polyisocyanates have a high level of hardness and a low level of fragility, and also has a reduced coefficient of thermal expansion. The invention is described in more detail in the following working examples.

The initial components for production of the novel polyaddition products of transparent, compact polyisocyanates, and the amounts used are given in Table 1. In order to produce the products, the respective polyols and catalysts are intensively mixed with each other. The isocyanate or isocyanate mixture was then added, and the mixture was again intensively homogenized. The components were controlled at 50 ° C during the addition and mixing. The mixtures were then directly manually loaded into a mold at 60 ° C, or 80 ° C in the case of Example 3, of dimensions 20 x 25 x 0.4 cm, and the mixtures were reacted for a period of 10 minutes. Table 1 Example 1 Polyol A [g] 60 Polyol B [g] '60 690 Polyol C [g] 20 20 20 Polyol D [g] 20 20 20 Cat A [g] 0.1 0.2 0.1 Cat B [g] 0.1 0.1 0.1 Cat C [g] - NCO A [g] 250. 32.9 NCO B [g] - 131.6 150.3 NCO: OH 1 1.1 1.1 Polyol A: polyether polyalcohol with a hydroxyl number of 925 mg KOH / g, prepared by the reaction of trimethylol propane with ethylene oxide; Polyol B: polyether polyalcohol with a hydroxyl number of 875 mg KOH / g, prepared by the reaction of trimethylol propane with propylene oxide; Polyol C: polyether polyalcohol with a hydroxyl number of 770 mg KOH / g, prepared by reaction of ethylenediamine with propylene oxide; Polyol D: polyether polyalcohol with an average functionality of 2.7 and OHI of 60 mg TKOH / g, based on adipic acid, diethylene glycol and trimethylol propane; Cat. A: tin catalyst (Witco Formez UL 32); Cat. B: 33% solution of diazabicyclooctane concentration in dipropylene glycol; Cat. C: 1, 8-diazobicyclo [5.4.0] -7-undecene (Air Products Poly-cat DBU); NCO A: isocyanate A: oligomeric hexamethylene diisocyanate, isocyanuratized (BASF Aktiengesellschaft Basonat® Hl 100), NCO content 21.5%; NCO B: isocyanate B: IPDI, NCO content 37.8%. In another example, example 4, the reaction was not carried out by the one-step method as in examples 1 to 3, but by the prepolymer method. The description of the components are as given in the key for table 1.

Example 4: The isocyanate prepolymer was prepared by reacting 200 g of NCO B with 30 g of polyol B at 80 ° C. The polyol in this case was added dropwise to the isocyanate for a period of one hour. After the addition, the reaction was carried out to completion for two hours at the same temperature. To ensure complete reaction of the prepolymer and accelerate it, it may be advantageous that the catalysts are present during the preparation. For example, from 0.001 to 0.1% by weight of the catalyst in the isocyanate, based on the weight of the isocyanate, has proven success. This amount of catalyst is relative to the preparation of the prepolymer, and can be used in addition to the amounts of the catalyst already described. The appropriate catalysts were described earlier in the text. 209 g of prepolymer were then injected into a closed plate mold whose temperature was 100 ° C, together with a mixture of 50 g of polyol B, and 25 of polyol C, 25 g of polyol D, 1.0 g of Cat. and 1.25 g of Cat. C, using a high pressure machine and the RIM process. The components were maintained at 60 ° C during this process. The reaction in the mold was carried out for a period of 3 minutes. The novel products produced in Examples 1 to 3 were quenched at 120 ° C after the reaction for a period of one hour. The transparent, novel products had the properties given in table 2.

Table 2: n.d .: not determined.

The glass transition temperature was determined using DSC (differential scanning calorimetry). This glass transition temperature gives the temperature at which an amorphous material becomes mobile, that is, softens. As can be seen from the elevated vitreous transition temperatures, the products in this way have particularly good thermal resistance. The coefficient of thermal expansion is defined as the factor by which molded parts expand / elongate by degrees Celsius of temperature increases. The novel products had the desired high level of hardness. The hardness is measured as Shore B hardness in accordance with DIN 53505.

Claims (10)

REVTNDICATIONS

1. A process for producing polyaddition products of transparent, compact polyisocyanates by reaction of: (a) isocyanates with (b) compounds reactive to the isocyanates, if desired in the presence of (c) catalysts and (d) auxiliaries and / or additives, comprising using as (b) a mixture of compounds reactive to isocyanates, a mixture (i) that has an average functionality of > 3 and a medium of average hydroxyl number from 300 to 950 mg KOH / g.

2. A process as recited in claim 1, wherein a mixture used as (i) comprises the following components: from 45 to 99% by weight of a mixture (ii) comprising at least one polyether polyalcohol, wherein the mixture ( ii) has an average functionality of at least 3, preferably from 3.1 to 6, and an average hydroxyl number from 650 to 950 mg KOH / g, preferably 700 to 940 mg KOH / g, and from 1 to 55% by weight of a mixture (iii) it comprises at least one polyester polyol, wherein the mixture (iii) has an average functionality from 2 to 3 and an average -hydroxyl number from 20 to 200 mg KOH / g.

3. The process as recited in claim 1, wherein the isocyanates used as (a) are aliphatic and / or cycloaliphatic isocyanates. The process as recited in claim 1, wherein the isocyanates used as (a) are aliphatic and / or cycloaliphatic diisocyanates, in particular 1,6-hexamethylene diisocyanate, the isomers of dicyclohexyl diisocyanate and / or isocyanate-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane, which can, if desired, be isocyanurated, biuretized and / or modified with urethane groups. 5. The use of mixtures (i) as claimed in claim 2 for the production of transparent, compact polyisocyanate polyaddition products. 6. A compact, transparent polyisocyanate polyaddition product obtainable by a process as recited in claim 1. 7. The use of the transparent, compact polyisocyanate polyaddition products as claimed in claim 6 as outer layers to protect surfaces. 8. The use of the transparent, compact polyisocyanate polyaddition products as claimed in claim 6 as a glass substitute. 9. The use of the polyaddition products of transparent, compact polyisocyanates as claimed in claim 6 such as roofs for the sun, front windows, rear windows or side windows in automobile or aircraft construction and / or as lamp covers. 10. A roof for the sun, a front window, a rear window, or a side window in the construction of automobiles or aircraft or as a cover for lamps containing polyaddition products of transparent, compact polyisocyanates as claimed in claim 6 .