DE1027394B - Process for the production of foams - Google Patents

Description

Process for the production of foams The subject of the patent application F21339 IVb / 39b is a process for the production of foams from polyoxy- and / or polycarboxyl compounds and polyisocyanates, with as polyisocyanates Solutions containing more than one NCO group and at least one isocyanuric acid ring Polyisocyanates derived from monomeric di- or polyisocyanates, optionally under Addition of monoisocyanates obtained are used in liquid monomeric isocyanates will.

The elastic and rigid foams obtained by this process are characterized by improved physical properties compared to those obtained with the sole use of monomeric polyisocyanates will. Another significant advantage of this mode of operation arises from the The fact that the polyisocyanate mixtures deal with the mostly viscous reaction components Can be mixed very easily, which makes production much easier the foams result.

Modifying the procedure of German patent application F 21339 IVb / 39b has now been found that in the production of foams from Polyoxy and / or polycarboxyl compounds and at least two isocyanate groups containing polymers, instead of solutions of more than one NCO group and at least one isocyanuric acid ring-containing polyisocyanate, advantageously solutions of higher molecular weight polymeric reaction products containing more than one NCO group of monomeric di- or polyisocyanates with a deficit of compounds that contain one or more active hydrogen atoms.

The benefits obtained by using the higher molecular weight modified nPolyisocyanates "are obtained in a mixture with monomeric liquid polyisocyanates, are manifold. The mixing of the foam-forming components when used alone Use of monomeric liquid polyisocyanates, primarily diisocyanates, with the in any case, higher viscosity hydroxyl and / or carboxyl group carriers are common difficult, and often longer periods of time become the necessary homogeneous distribution of the components required. As a result, however, the possibility of premature payments is undesirable Given reactions that adversely affect the end product.

The higher molecular weight modified polyisocyanates mixed with In contrast, monomeric liquid polyisocyanates are liquids at room temperature , the viscosity of which is in any case higher than that of the monomeric polyisocyanate and can be set as required from case to case. These higher viscosity modified ones Polyisocyanate mixtures can be easily and quickly mixed with the hydroxyl and / or carboxyl group carriers of various constitution and the other foam components mix. Undesired preliminary reactions of the non-homogenized mixtures will be thereby pushed back to a minimum.

The quick and intensive mixing of the components still brings Other advantages. In this way, much more stable foams are obtained that are in the state of origin show no tendency to coincide, even if larger approaches are processed will. The good mixing behavior of the modified polyisocyanate mixtures can It also understand that the foams made with it are finer and more regular have formed pore structure, which generally results in improved physical Properties is expressed.

Polyisocyanate-based foams are preferably made by blending liquid components produced at room temperature. Herein lies an important one Advantage over other methods, but also a certain limitation, as a number readily accessible and also suitable diisocyanate is solid at room temperature and therefore cannot be used without further ado. Through the present procedure it has now become possible to also use these solid diisocyanates after partial Reaction with compounds containing active hydrogen atoms and then Polymerization (trimerization) and mixing of the higher molecular weight obtained modified Polyisocyanates with liquid monomeric polyisocyanates for the production of foams to be used, whereby further valuable variations of the end products can be achieved.

The higher molecular weight modified ones used for foam production Polyisocyanate mixtures contain mainly tri-or in the desired metered amount high-functional isocyanates. This fact brings advantages especially in the Manufacture of rigid foams. The hydroxyl and / or suitable for this sector Carboxyl group carriers must namely have a relatively high degree of branching be excellent. The higher this degree of branching, the higher is also with unchanged number of reactive hydroxyl or carboxyl groups the viscosity of connections. However, the starting components also have viscosities that are too high like too low undesirable. When using the present polyisocyanate mixtures for the production of rigid foams one is now able to be less strong branched, i.e. less viscous and therefore easier to process hydroxyl and / or To use carboxyl group carriers, since some of the necessary branches is already preformed in the higher molecular weight polyisocyanate mixture.

Those used according to the invention and containing more than one NCO group high molecular weight soluble isocyanate compounds, for their production in the framework of the present application no protection is claimed, are made of monomeric di- or polyisocyanates obtained, which are initially obtained with a deficit of compounds, which contain one or more active hydrogen atoms, converts. Examples of suitable ones Compounds are aliphatic, hydroaromatic or aromatic monofunctional Alcohols such as methanol, butanol, n-octyl alcohol, oleyl alcohol, allyl alcohol, cyclohexanol, Phenol, substituted phenols, cresols, glycols such as ethylene glycol, 1,3- or 1,4-butylene glycol, 1,6-hexanediol, diethylene glycol, 2,2,4-trimethylpentanediol-1,3, 2-ethylhexanediol-1,3, 2,2-Dimethylpropylene glycol-1,3, hydrogenated 4,4'-dioxydiphenyl-dimethylmethane, polyfunctional Alcohols such as trimethylolpropane, glycerine, pentaerythritol, and also polyfunctional ones Phenols such as pyrocatechol, resorcinol, hydroquinone, 4,4'-dioxydiphenyldimethylmethane. Furthermore, there are compounds from the substance groups of the aliphatic or aromatic, primary or secondary, mono- or polyfunctional amines or amino alcohols or aminophenols in question. Basically all compounds have active hydrogen atoms suitable for modification, so that the above list is only in the sense of a Explanation is to be understood. Of course, mixtures of the individual Components are used.

As examples for the production of the higher molecular weight »polyisocyanates« suitable isocyanates may be mentioned: tetramethylene diisocyanate, hexamethylene diisocyanate, Decamethylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 1-tert-butyl-3,5-xylylene diisocyanate, 4,6-dimethyl-1,3-xylylene diisocyanate, cyclohexyl-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 1-alkylbenzene-2,4-diisocyanate, 1-alkylbenzene-2,6-diisocyanate, 2,6-diethylbenzene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenyl-dimethylmethane-4,4'-diisocyanate. 3,3'-dimethoxydiphenylmethane-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, 1-methylbenzene-2,4,6-triisocyanate, Triphenylmethane-4,4 ', 4 "-triisocyanate.

The abovementioned compounds are reacted with the monomeric di- or polyisocyanates in a known manner by simply combining the components at room or elevated temperatures, possibly also with the use of solvents. The quantitative ratio is chosen so that, after the reaction has taken place, the resulting isocyanate-containing intermediate has an NCO content of more than 25%. This is illustrated by two examples: If 1 mol of toluene-2,4-diisocyanate (174 g) is reacted with 0.75 mol (34.5 g) of ethyl alcohol, the result is an addition product with an NCO content of 25.18 ° / O. Or when 1 mole of toluylene-2,4-diisocyanate (174 g) is reacted with 0.28 mole (63.84 g) of 4,4'-dioxydiphenyldimethylmethane, an addition product containing 25.43 % NCO is obtained.

Advantageously, however, the amount of the compounds to be used for modification is kept smaller than indicated above. Good results are obtained if not more than 25 % of the NCO groups of the polyisocyanate to be modified are bound by the addition reaction.

These known, isocyanate-containing reaction products are then subjected to a polymerization, for. B. in the manner listed in German patent application F 21339 IVb / 39b. It is enough z. B. heating to elevated temperatures of 150 to 200 ° C, for example, for a long time. The goal is reached faster and under milder conditions if this temperature treatment in the simultaneous presence of catalysts, such as. B. of tert. Amines or metal compounds soluble in organic medium is made. The polymerization can be carried out in the presence of strongly basic tertiary, in particular aliphatic, amines, starting from such monomeric organic polyisocyanates which contain at least one isocyanate group in an aromatic bond. The polymerization is carried out only partially in each case, so that the higher molecular weight modified polyisocyanate obtained is ultimately characterized by an NCO content of not less than 10 % . As a rule, these modified polymerized isocyanates are solid bodies or viscous oils at room temperature.

Those prepared as described above and used according to the invention modified polyisocyanate mixtures are converted into liquid monomeric polyisocyanates solved. Suitable for this are e.g. B. 1-methylbenzene-2,4-diisocyanate, 1-methylbenzene-2,6-diisocyanate, 1-methylbenzene-3,5-diisocyanate, tetramethylene, hexamethylene, decamethylene diisocyanate, m- or p-xylylene diisocyanate, 2,4,4'-diphenyl ether triisocyanate (liquid crude product). According to the invention, these liquid polyisocyanate mixtures come, depending on whether they are rigid or elastic foams are to be produced in different quantities to use. The general rule is the proportion of the monomeric liquid polyisocyanate to keep small if highly cross-linked rigid foams are desired, or on the other hand to use a lot of monomeric polyisocyanate as a solvent when more elastic types should be produced. In any case, it is expedient to use the modified polyisocyanate mixtures set so that liquid solutions are obtained at room temperature. Viscosities from 50 to 300 cP at 25 ° C have proven themselves well in foam production. But solutions with a viscosity of 1000 cP at 25 ° C are also successful to process.

In the preparation of the modified polyisocyanate mixtures you can also auxiliaries such as B. fire retardants and / or plasticizers are used, provided they do not contain any isocyanate-reactive hydrogen atoms. Examples include trichloroalkyl phosphates, highly chlorinated paraffins and esters on Based on aliphatic, hydroaromatic or aromatic polycarboxylic acids.

As hydroxyl and / or carboxyl group carriers are used for foam production numerous types suitable. Mono- or polyfunctional alcohols may be mentioned and linear carboxylic acids or oxycarboxylic acids prepared by known methods or branched polyesters that also contain heteroatoms, double or triple bonds as well as saturated or unsaturated fatty acids or fatty alcohols as modifying agents Components may contain linear or branched, linear or polyester amides branched polyalkylene ethers or thioethers, from di- or polyols and styrene oxide accessible ethers with hydroxyl end groups, epoxy resins, hydrogenation products of ethylene-olefin-carbon oxide copolymers, phenol-formaldehyde resins reacted with alkylene oxides.

The foam itself is produced by known processes at room temperature or elevated temperatures by simply mixing the modified polyisocyanate mixtures with the hydroxyl and / or carboxyl groups, with water, accelerators, emulsifiers and other auxiliaries being used if necessary. (The addition of water can be superfluous in those cases in which the compounds with several reactive hydrogen atoms are polyester or other high molecular weight compounds that contain free carboxyl groups. B. in the French patent 1 074 713 are described.

Example 1 80 parts of a polyester obtained from 5.1 moles of adipic acid, 1 mole of phthalic anhydride and 8.4 moles of hexanetriol and having a hydroxyl content of 8.5% are mixed with 20 parts of a polyester made from 1.43 moles of adipic acid, 1 mole of hexanetriol and 1 mole of 1,3-butylene glycol obtained polyester with a content of 6.5% hydroxyl groups and mixed with an activator mixture of 2 parts of an ester obtained from 2 moles of diethylethanolamine and 1 mole of adipic acid and 5 parts of a 54% aqueous solution of the Sodium salt of castor oil sulfate intensively stirred together. 112 parts of a modified polyisocyanate mixture with an NCO content of 32.4% are added to this mixture with thorough stirring. With vigorous foaming, a foam is obtained which is distinguished by the following values Comparative Foam watch with according to monomeric Example toluene diisocyanate Volume weight, kg / m3 .......... 38 32 Compressive strength, kg / cm2 ....... 2.27 1.29 Impact strength, kg / cm. . . . . . . . 0.12 0.12 Water absorption, percent by volume 1 1 Heat resistance, ° C ...... 160 124 The modified polyisocyanate mixtures are prepared as follows: 0.17 mol of 2,2,4-trimethylpentanediol-1,3 (24.8 parts) are added to 1 mol of tolylene diisocyanate (174 parts) at 60.degree ° C heated. The NCO determination, in accordance with the calculation, after one hour of reaction gives a content of 35 (19 /,). 0.2 part of a tertiary amine obtained from 1 mole of n-methyl diethanolamine and 2 moles of phenyl isocyanate is now added to the reaction mixture Heated to 160 ° C. and left at this temperature for 3 hours. In the course of this time, the NCO content falls to 25.0%. No protection is claimed at this point for this production process. After cooling to 100 ° C., the mixture becomes diluted with 103 parts of tolylene diisocyanate The modified polyisocyanate mixture produced in this way is characterized by an NCO content of 32.40% and a viscosity of 147 cP at 25.degree.

The modified polyisocyanate mixture can be very easily incorporated into the Incorporate the above polyester mixture. A comparison of the physical values of the The foam obtained shows the use of pure toluene diisocyanate an improvement in compressive strength and heat resistance. Come in addition, that the foam shows no signs of shrinkage after foaming. Self no shrinkage occurs when stored in boiling water for a quarter of an hour on. A foam made using monomeric toluene diisocyanate shows, on the other hand, very strong shrinkage, both shortly after foaming and even after a quarter of an hour cooking rehearsal.

Example 2 100 parts of a polyester prepared from 1 mole of adipic acid, 2 moles of phthalic anhydride, 1 mole of oleic acid and 5 moles of glycerol and having a hydroxyl content of 13.20 /, are thoroughly mixed with the same activator mixture as described in Example 1 and, with the addition of 140 parts of the modified polyisocyanate mixture described in Example 1 foamed after vigorous stirring. The foam does not show any shrinkage in contrast to the comparison foam using monomeric tolylene diisocyanate. Comparative Foam watch with according to monomeric Example toluene diisocyanate Volume weight, kg / m3 .......... 44 42 Compressive strength, kg / cm2 ....... 1.81 1.41 Impact strength, kg / cm. . . . . . . . 0.13 0.07 Water absorption, percentage by volume 1.2 2 Heat resistance, ° C ...... 187 162 Example 3 80 parts of a polyester prepared from 2 mol of adipic acid, 0.4 mol of phthalic anhydride, 2.4 mol of trimethylolpropane and 0.8 mol of 1,3-butylene glycol with a hydroxyl content of 10 % in a mixture with 20 parts of a 1.43 mol Adipic acid, 1 mol of hexanetriol and 1 mol of 1,3-butylene glycol obtained polyester with a hydroxyl content of 6.50 /, are foamed with the activator mixture described in Example 1 and with the addition of 99 parts of the modified polyisocyanate mixture described in more detail below, after vigorous stirring. A rigid foam is obtained which, compared with one produced using monomeric tolylene diisocyanate alone, does not show any signs of shrinkage and, moreover, is also distinguished by an increased compressive strength. Comparison - Foam foam with according to monomeric Example toluene diisocyanate Volume weight, kg / m3 .......... 40 32 Compressive strength, kg / cm2 ....... 2.19 1.52 Impact strength, kg / cm. . . . . . . . 0.20 0.09 Water absorption, percent by volume 1.8 2.3 Heat resistance, ° C ...... 148 115 The modified polyisocyanate mixture is obtained as follows: Preparation of the starting material: 0.15 mol of 4,4'-dioxydiphenyldimethylmethane (34.2 parts) are added to 1 mol of tolylene diisocyanate (174 parts) at 100 ° C. and the mixture is heated for 1 hour. After this time, the reaction mixture has an NCO content of 35 % in accordance with the calculation. After adding 0.2 parts of the tert described in Example 1. Amine and heating to 160 ° C. for a period of 2 hours 40 minutes, the NCO content of the mixture falls to 25.6 % .

After dilution with 320 parts of toluene diisocyanate, a modified one is obtained Polyisocyanate mixture obtained by a content of 39.2% NCO, a viscosity of 148 cP at 25 ° C and a refractive index of nD = 1.5881.

Example 4 100 parts of an ethylene-propylene-carbon monoxide-polymer which has been hydrogenated after the polymerization and a hydroxyl content of 3.50, contains / is with a activator mixture of 1 part of dimethylbenzylamine, and 5 parts of a 54 ° / jgen aqueous solution of the sodium salt intensely stirred together by castor oil sulfate. This mixture is admixed with 60 parts of a modified polyisocyanate mixture of the composition described below, with thorough stirring. With strong foaming, a semi-rigid foam with a density of 43 kg / m3 and a compressive strength of 0.82 kg / cm? Is obtained.

The modified polyrisocyanate mixture is obtained as follows: Preparation of the starting material: 0.2 mol (20.8 parts) of 2,2-dimethyl-1,3-propanediol are added to 1 mol of tolylene diisocyanate (174 parts) at 100 ° C. for 1 hour heated and then after increasing the temperature to 160'C and adding 0.2 parts of the tert described in Example 1. Amine heated for a further 5 hours.

The reaction product obtained after this time with an NCO content of 24.00 /, is diluted with 153 parts of toluene diisocyanate. The mixture obtained has an NCO content of 40.6% and a viscosity of 196 cP at 25 ° C.

Example 5 100 parts of a polyester obtained from 14 moles of adipic acid and 15 moles of diethylene glycol and containing 1.52% hydroxyl are mixed with an activator mixture of 3 parts of an ester obtained from 2 moles of diethylethanolamine and 1 mole of adipic acid, 1.5 parts of diethylammonium oleate, 1 part a 54% aqueous solution of the sodium salt of castor oil sulfate and 2 parts of water were intensively stirred together. This mixture is mixed with 12.4 parts of the polyisocyanate mixture described below and 29 parts of tolylene diisocyanate, with thorough stirring. Vigorous foaming results in an elastic foam with a fine and uniform pore structure and the following physical data Foam with Foam monomeric according to toluene Example diisocyanate alone Volume weight, kg / m3 .......... 43 46 Elasticity, R /, ............... 29 23 Notch Strength, kg / cm. .... ... 0.64 0.41 Tensile Strength, kg / cm '......... 1.83 1.08 Strain, % .. . . . . . . . . . . . . . . . 191 141 The polyisocyanate mixture is obtained by reacting 1 mol (174 parts) of toluene diisocyanate with 0.17 mol (45.5 parts) of oleyl alcohol and subsequent polymerization at 160 ° C. in the presence of 0.3 parts of the tert described in Example 1. Amine and diluting the reaction product containing 25.7% NCO with 66 parts of tolylene diisocyanate. The key figures of the polyrisocyanate mixture produced in this way are 27.00 /, NCO at a viscosity of 132 cP at 25 ° C.

Claims (2)

PATENT CLAIMS: 1. Process for making foams from Polyoxy and / or polycarboxyl compounds and at least two isocyanate groups containing polymers in modification of the process according to patent application F 21339 IVb / 39b, characterized in that instead of solutions of more than one NCO group and at least one isocyanuric acid ring-containing polyisocyanate solutions of higher molecular weight polymeric reaction products containing more than one NCO group of monomeric di- or polyrisocyanates with a deficit of compounds that containing one or more active hydrogen atoms can be used. 2nd embodiment of the method according to claim 1, characterized in that the production of the Foams in the presence of liquid plasticizers and / or flame retardants takes place, this preferably being the solutions of the liquid, more than one NCO group having polymeric reaction products.