DE1803723B2 - Mixtures based on aromatic polyisocyanates, process for their production and use for the production of polyurethane foams - Google Patents

Description

2. Mixtures according to claim 1, characterized in that they are used as aromatic polyisocyanates contain aromatic diisocyanates.

3. Mixtures according to claim 2, characterized in that they are used as aromatic isocyanates Contain toluene diisocyanate.

4. Mixtures according to claim 3, characterized in that the tolylene diisocyanate is essentially consists of 80% of the 2,4-isomer and 20% of the 2,6-isomer

5. Mixtures according to Claims 1 to 4, characterized in that they jo in addition to tolylene diisocyanate contain other aromatic polyisocyanates.

6. Mixtures according to claim 5, characterized in that they are used as a further aromatic polyisocyanate 4,4'-methylene-bis (phenyl isocyanate) contain.

7. Mixture according to Claims 1 to 6, characterized in that J5 characterized in that they contain isocyanurate radicals in aromatic isocyanate trimers of an isocyanate group functionality of at least an average of 3 included.

8. Process for the preparation of mixtures according to Claims 1 to 7, characterized in that aromatic polyamines are reacted with phosgene to give aromatic polyisocyanates and the Polyisocyanates to trimers containing isocyanurate radicals and having an average isocyanate group functionality trimerized by at least 1.5.

9. The method according to claim 8, characterized in that the trimerization up to one Content of non-volatile phosgenation by-products and / or isocyanurate residues, which leads to higher than indicated, and then the trimerization product with aromatic polyisocyanates mixes.

10. The method according to claim 9, characterized in that the trimerization product with blends raw aromatic polyisocyanates.

11. The method according to claims 9 or 10, characterized characterized in that the trimerization product with purified aromatic polyisocyanates mixes.

12. The method according to claim 8, characterized in that one from the phosgenation obtained product of a distillation to remove aromatic polyisocyanates and increase the Content of non-volatile phosgenation by-products and of isocyanurate radicals.

13. The method according to claims 8 to 12, characterized characterized in that the trimerization in

Presence of guanidines of the formula

'· Ί ² \ ³
R ₁ R ₂ N-el = NX.) - NR ₃ R ₄ and / or Isobigua-

nidinen of the formula

3
NR ₉ R ₁₀

as catalysts, where the radicals R, which can be the same or different, are Q-C4-alkyl radicals, C ₃ -Ce -cycloalkyl radicals or 2-oxa- or 3-oxabutyl or each of the pairs of R (Ri-R ₂ , R ₃ -Rt, Rs-Re, Rz-Rs and R9-R10) together can form a 4- to 9-membered heterocyclic ring with not more than 2 heteroatoms (N, S or O) including the guanidine or isobiguanidine nitrogen, where further X hydrogen atoms, Ci-Q-alkyl radicals, C ₃ -Q-cycloalkyl radicals, Q-Cis-aryl radicals, C7-Cis-alkaryl or aralkyl radicals or carbamoyl radicals of the formula - CONHZ and Z is in each case the monovalent radical which by removal an isocyanate group is obtained from the aromatic polyisocyanate, and finally the organic radicals can be substituted with chlorine, bromine or Ci-C2-alkoxy groups.

14. The method according to claims 8 to 13, characterized in that after the reaction of the aromatic polyamines with phosgene some isocyanate groups with two or more active hydrogen atoms containing compounds to form urethane and / or urea bonds

15. The method according to claim 14, characterized in that there is used as compounds with two or more active hydrogen atoms high molecular weight polyalkylene ether glycols, polyester glycols and / or other polyols, low molecular weight polyols, polyamines and / or water are used.

16. The method according to claim 15, characterized in that as compounds with two or more active hydrogen atoms, polyols with a molecular weight of 80 to 500 and 3 to 8 hydroxyl groups used.

17. Use of the mixtures according to claims 1 to 7 for the production of rigid polyurethane foams, characterized in that the mixtures with polyether and / or polyester polyols reacted in the presence of a propellant.

Rigid polyurethane foams are well known. They are used in technology for example Used for insulation and construction purposes. Any improvement to these foams or their starting materials is of technical importance. For example, US Pat. No. 3,215,652 Proposed use of a toluene diisocyanate that does not contain any volatile (by-products) Contains soluble substances and by phosgenation of toluylenediamine in the presence of a solvent is prepared, wherein the solvent and a certain amount of toluene diisocyanate are distilled off and the desired product remains as a residue, sometimes as "raw" or "not"

distilled "material is referred to. Crude polyisocyanates containing non-volatile by-products, are currently on the market and are used in the manufacture of polyurethane foams. The non-volatile by-products are complex, high-molecular, tarry materials that are essentially insoluble in hexane. It is believed that they consist largely of monomeric and polymeric biuret molecules that contain free isocyanate groups. Within the scope of this description and the claims, that includes in connection with phosgenation of tolylenediamines, phenylenediamines and 4,4'-diaminodiohenylmethane Used expression "non-volatile by-products" the materials which after the distillation of the diisocyanates and des Solvent at a final temperature of the bubble of 200 ° C under a pressure of 1 to 5 mm Hg at the Toluenediamines and phenylenediamines and from 240 ° C under a pressure of 1 to 2 mm Hg 4,4'-Diaminodiphenylmethane remain as the distillation residue.

It is also known that isocyanates can be subjected to conditions under which they polymerize. For example, US Pat. No. 2,978,449 describes the trimerization of polyisocyanates under Formation of isocyanurates, which have the characteristic cyclic 6-membered isocyanurate residue

(-NC (O) -J ₃

contain. The patent suggests possible uses primarily as adhesives. So far has been however, the trimerization of crude polyisocyanates into mixtures has not yet been proposed entirely contain certain proportions of non-volatile by-products and isocyanurate residues, which are extremely prove particularly advantageous for the production of rigid polyurethane foams.

The US-PS 30 97 191 describes the new isocyanate of the methylenedianiline type. These liquid polyisocyanates are made by phosgenating a polyanum composition prepared, in turn, by condensing formaldehyde with at least 2 moles of mixed aromatic amines, e.g. B. aniline and o-toluidine have been obtained. It is also described that the isocyanates can be reacted with polyhydroxy compounds to form polyurethanes, which for Find production of foams use. In addition, the polyisocyanates can with the help of Alkali or alkaline earth compounds converted into their polymeric form as catalysts, e.g. B. trimerized will. Trimerized crude polyisocyanates are neither described nor suggested.

The US-PS 31 08 100 describes the polymerization and thus the trimerization of polyisocyanates with Using organic bases containing a hydroxyl ion as catalysts. The polyisocyanates can in the form of their reaction products with z. B. phenols, malonic acid esters and diphenylamine or im monomer-free state can also be used in solution of the isocyanate from which it is made have been. They can also be used as a mixture with other isocyanates. From this Nothing can be found in US-PS which describes and describes the mixtures according to the invention suggests.

The US-PS 32 78 492 in turn describes the polymerization or trimerization of organic Isocyanates using special organometallic compounds as catalysts.

U.S. Patent No. 3,280,066 describes almost completely trimerized tolylene diisocyanates, i.e. they are almost free of monomeric toluene diisocyanate. In sharp contrast, the mixtures contain according to the present invention, large proportions of monomeric diisocyanate. This U.S. patent describes neither does it specify any combination of crude polyisocyanates and trimerized polyisocyanates this combination is close.

BE-PS 6 80 380 or the corresponding GB-PS 1146 661 describes the production of Isocyanurate foams made from purified or crude polyisocyanates by trimerization in the presence a blowing agent and optionally water or a low molecular weight polyhydroxy compound. Around To obtain somewhat comparable foams from TDI according to the present process, one would have to start from an isocyanate mixture which contains at least 19.4% by weight of isocyanurate residues, which is outside Another difference is that according to the present invention the trimers are preformed, which reduces the heat build-up during foam formation with the advantage that the char is reduced and the shrinkage of the foam on cooling is suppressed will. Neither the mixtures according to the invention nor their preparation are described by the BE-PS or suggested.

In the subsequently published NL-PS 67.05694 it is pointed out that the procedure of the BE-PS 6 80 630 is not of interest in practice. Instead, the use of a polyol is superior Suggested molecular weight with the same crude diisocyanatodiarylmethane. It should be noted that these two patents the direct production of rigid foams with the formation of isocyanurate rings suggest in situ, and that it does not suggest, first a trimerized crude polyisocyanate and then use it to make a hard foam. One such Direct process is impractical, especially when the isocyanate is derived from a tolylenediamine.

There is still a need for a functional one Process that eliminates the disadvantages of the known processes.

In J. Org. Chemistry, December 1963, pp. 3527-3530 (F Iy η η et al.) The use becomes more certain substituted guanidines and isobiguanidines as catalysts for the trimerization of phenyl isocyanate described. This reference does not describe the trimerization of polyisocyanates.

The disclosure of JA patent application 15 680/64 is similar to US Pat. No. 3,215,652 discussed above has been. These are raw polyisocyanate compositions, however, trimerization is neither described nor suggested.

JA patent publication 20717/65 corresponds the US-PS 32 59 626 and describes a trimerization process for halogenated isocyanates.

JA patent publication 21248/63 and its British equivalent GB-PS 10 04 924 describe the manufacture of raw MDI and its uses

b5 in foams. From trimerization of the raw Starting materials is out of the question.

The JA patent publication 3997/64 describes the use of trimerized isocyanates to produce

production of foams. The trimerization of crude polyisocyanates or those obtained from them Mixtures according to the present invention are neither described nor suggested.

The JA patent publication 13 0.17 / 66 and her almost equivalent GB-PS 9 08 337 have a similar disclosure as BE-PS 6 80 380 and the NL-PS 67.05694, which have already been dealt with above. Isocyanurate foams are described, which are produced by simultaneous trimerization during foam formation. A very big one Excess of a polyisocyanate is combined with a compound having active hydrogen atoms, the —OH and / or - contains COOH groups, in the presence of a blowing agent and a trimerization catalyst implemented The end product contains substantial amounts of isocyanurate residues, which during the foaming reaction are formed. This literature was cited to allegedly show that crude polyisocyanates have been considered for use in a foam manufacturing process, which leads to foams that contain isocyanurate residues. In this literature it is mentioned that partially polymerized polyisocyanates can be used. Now if you have these two accidental Combining data, it could be argued that the trimerized crude products according to the present invention are thereby suggested. However, this is not the case. All of the revelation this literature is directed to a method of making a foam using large amounts of trimer are formed during foam formation, whether any trimer or any Phosgenation by-product are present in the starting isocyanate. The requirement in this literature that the isocyanate index must be at least 200, means that at least half of the before Isocyanate groups present in foam formation are converted into isocyanurate residues. In the case of TDI this means that if half of the NCO groups are converted to isocyanurate radicals before foam formation the isocyanurate group content of the starting isocyanate would be 24%, which is essential is above the upper limit of the amount claimed according to the invention. It should be mentioned that the 24% concentration is the lower limit that can be derived from it.

Another major difference between these known methods and the present one Invention lies in the fact that the isocyanurate formation takes place at the same time as the urethane formation. from The disadvantage of the process described is the greater heat development during foam formation from a given set of respondents. This increases the risk of charring and shrinking of the foam, especially when making thick foam parts. Also, the fact that Competing reactions take place in the known method, to differences in the Lead final compositions of the foams obtained.

From this it can be seen that JP Patent Publication 13 037/66 is based on one of the present Registration is directed to quite different manufacturing processes for foams and also to Foams that are substantially different in their composition from those made from the Polyisocyanate mixtures are obtained according to the invention.

JA patent publication 2799/60 corresponds to US-PS 29 78 449, which has already been dealt with above.

In the JA patent publication 6397/63 a process for the trimerization of isocyanates is described, using certain catalysts which are alkali and alkaline earth compounds. Furthermore, the polymerization in the presence of a

ίο Mono-N-substituted carbamic acid ester carried out.

JA patent publication 10 550/64 relates to the trimerization of polyisocyanates contained in N.N-dialkylamides, such as B. dimethylformamide are dissolved.

JA patent publication 118/66 relates to a Process for the trimerization of polyisocyanates using a tertiary imine as a catalyst.

The JA patent publication 13 253/63 relates to the production of paints from trimerized polyisocyanates, which are almost free from starting monomer polyisocyanates. There is nothing of crude isocyanates testified. In contrast, the blends of the present invention have large amounts of monomeric Polyisocyanates.

JA patent publication 3691/65 relates to the trimerization of polyisocyanates in solvents, which have a low water content.

The JA patent publication 17 399/65 corresponds to DT-AS 12 03 792 and relates to the trimerization of Polyisocyanates in the presence of ethylene imines as catalysts.

JA patent publication 5838/65 describes a process for the trimerization of polyisocyanates in Presence of a mixture of a tertiary amine and an aldehyde.

Journal of Cellular Plastics, January 1965, 85-90, describes the production of isocyanurate foams, the trimerization of the polyisocyanate taking place during foam formation. From the description of the prepolymer that was foamed (p. 87, col. 2,3, full paragraph) shows that about 84% of the im Isocyanate groups present at the starting TDI intervene in the isocyanurate formation reaction. In contrast for this purpose, the foams are formed from the compounds according to the invention by urethane reaction.

The invention relates to mixtures based on aromatic polyisocyanates by

1. an amine equivalent of 103 to 130

2. an average functionality of at least two isocyanate groups and

3. a content of 9 to 25% of non-volatile phosgenation by-products and of 2.4 to 10.9% of isocyanurate residues that have an isocyanate group functionality in aromatic isocyanate trimers of at least 1.5 are included, with all information on the free isocyanate groups containing molecules are related.

In other words, the average functionality should be at least two isocyanate groups for all free Molecules containing isocyanate groups are in the mixture, while the isocyanurate-containing molecules regardless of whether it is polymeric trimers or monomeric trimers, a medium one Should have functionality of at least 1.5, preferably of at least 3, isocyanate groups. as

Non-volatile by-product content applies to the total weight of these materials, while the isocyanurate content only as the weight of the isocyanurate residues and not as the total weight of the isocyanurate containing Materials is expected.

Tolylene diisocyanates, which are readily available, are preferred? L · polyisocyanates. If the polyisocyanate is to be based on 4,4'-methylenebis (phenyl isocyanate) and is derived from 4,4'-diaminophenylmethane, the values of the characteristics mentioned should be in somewhat lower ranges and the amine equivalents in higher ranges. Other suitable polyisocyanates are the phenylene and / or naphthalene derivatives. Diisocyanates are generally preferred, but higher polyisocyanates can also be used for certain purposes, e.g. B. those that are prepared by phosgenation of crude 4,4'-diaminodiphenylmethane, which contains, for example, up to 45% by weight of polymeric polyamines and, for example, by condensation of aniline and formaldehyde in the presence of a mineral acid on the in the US Patent 26 83 730 described manner can be produced. The mixtures preferably contain a sufficient amount of the actual polyisocyanate to dissolve the remaining components, since this makes handling easier.

The isocyanate mixtures according to the invention can be prepared directly, e.g. B. by a usual Phosgenation processes according to, for example, US Patents 26 44 007, 26 83 160 and 26 80 127, wherein a crude polyisocyanate is formed from an aromatic polyamine, and subsequent trimerization, until the desired isocyanurate content is reached. This is generally the most economical preferred way. The manufacture can also be carried out by separately manufacturing one or more of the components and mixing that ingredient (s) with the other ingredient (s) other components. For example, a refined isocyanate can be trimerized separately and then added to a crude polyisocyanate. Optionally, a trimerized concentrate can be made and then diluted with crude or refined polyisocyanate, or a dilute trimerized Mixture can be prepared and then the isocyanurate concentration can be effectively increased by adding some of the Polyisocyanate is distilled off.

The trimerization can be carried out, for example, by the methods described in US patents

28 01 244, 29 54 365, 29 93 870, 32 52 942, 31 54 522 and

29 78 449 and in British patent specification 10 01 746 are described. The weight loss of isocyanate groups, determined according to ASTM D 1638-60 T, is essentially the same as the isocyanurate content in the trimerized product.

According to the invention it was found that guanidines of the general formula

R, R ₂ N - (U = NX '--NR ₃ R ₄ and / oc ^ r isobiguanidincn of the formula

N ( ¹ I.

4, 3
NX'NR _g R, "

are particularly good catalysts for the trimerization of aromatic polyisocyanates. In these formulas, the radicals R can be identical or different and _{stand for Q-Gi-alkyl radicals, C 3} -C 6 -cycloalkyl radicals or 2-oxa- or 3-oxabutyl, or any pairs of the radicals R (Ri-R ₂ , R3- R4, Rs-Re, R7-R8 and R9-R10) can together form a 4- to 9-membered heterocycle with a total of not more than two heteroatoms (N, S or O) including the guanidine or isobiguanide nitrogen atom. The radicals X stand for hydrogen atoms, Ci- Gt-alkyl radicals, C ₃ - Qs-cycloalkyl radicals, Q-Cis-aryl radicals, C ₇ -Ci ₈ -alkaryl or -aralkyl radicals or carbamoyl radicals of the formula - CONHZ, where Z is the monovalent radical obtained by removing an isocyanate group from isocyanate as described below. The organic radicals can be substituted with chlorine, bromine or Ci - Cr alkoxy radicals. Preferred catalysts are those with Ci-C ₄ -alkyl substituents or (only for X) hydrogen atoms, in particular 1,1,33-tetramethylguanidine, which is easily available and can be used to trigger a rapid but easily controllable trimerization, and 1,1,2,2,3,3,4-heptamethyl isobiguanide, which is so reactive that even a relatively inert aliphatic isocyanate can be trimerized without heat. Further suitable catalysts are, for example

1,1,2,3,3-pentamethylguanidine,

l, l, 3,3-tetramethyl-2-butylguanidine,

1,1,2,3,3-pentaethylguanidine,

1,1 AS-tetramethyl ^ -phenylguanidine,

1,1,3,3-tetramethyl-2- (4-chlorophenyl) guanidine,

l ^ -dimethyl-lß-diethylguanidine,

1,1,3,3-tetramethyl- (phenylcarbamoyl) -guanidine,
1,1,2,23,3-hexamethylisobiguanide and
l, li, 233-hexamethyl-4- (phenylrarbamoyl) -isobiguanide.

When X is hydrogen, it is believed that this hydrogen will react with the isocyanate to cause a carbamoyl residue is formed, as already mentioned. The catalysts can optionally be used together with other catalysts, for example alkali

xyden and compounds containing an ethylene imine ring can be used.

The various conditions of the trimerization depend on the isocyanate, the catalyst and its amount as well as the temperature. The preferred amount of catalyst is generally at least 0.05 to 2 percent by weight of the isocyanate. The catalysts are generally between - active 1O ⁰ C and 250 ° C. The isocyanates and trimers have limited stability at higher temperatures. Temperatures from 20 to 180 ° C. are preferred.

The trimerization can be carried out in an inert solvent, i.e. a solvent which is not active Contains hydrogen atoms. This is often useful for the preparation of the mixtures according to the invention and when high concentrations of the trimer occur, but this can Isocyanate itself has sufficient solvent power for dilute trimer mixtures and the preferred ones Have mixtures according to the invention.

bo The degree of trimerization can in general in a simple manner by adding an acid, e.g. B. hydrogen chloride or phosphoric acid, and more acidic Materials, e.g. B. an acid halide such as phosgene, benzoyl chloride, acetyl chloride and adipyl chloride

μ and set. Crude isocyanates therefore generally require a higher catalyst concentration because of their higher acidity compared to refined isocyanates. Of course you can

Trimerization catalysts also for the treatment of any polyisocyanates including the alkyl, Cycloalkyl, aralkyl, alkaryl and aryl polyisocyanates and mixtures thereof can be used.

The mixtures according to the invention are particularly suitable for the production of rigid polyurethane foams, which represent a further aspect of the invention. The production takes place in the usual Way by reacting the mixtures with polyether and / or polyester polyols in the presence of a blowing agent and usually in the presence of a catalyst. The one-step process is preferred, however can also use prepolymer and “quasi-prepolymer” processes for the production of foams the mixtures are applied, first of all the prepolymer with an excess of the isocyanate and then chain lengthening or crosslinking with polyol, polyamine or water. A preferred polyol for the manufacture of rigid foams is commercially available under Designation »Selectrofoam« -6406 available. It is believed that this is a polyether polyol that obtained by oxypropylation of sucrose.

Optionally, the isocyanate mixtures according to the invention can first be partially reacted with Compounds containing two or more active hydrogen atoms, e.g. B. high molecular weight (500 to 5000) Polyalkylene ether glycols, polyester glycols and / or higher polyols, low molecular weight (below 500) Polyols, polyamines and / or water, modified to form urethane and / or urea bonds form. Polyols which have a molecular weight of 80 to 500 and 3 to 8 are preferred for this purpose Contain hydroxyl groups, and amines, e.g. B. tolylenediamine and 4,4'-diaminodiphenylmethane. The degree of Modification is limited by the properties prescribed for the mixtures according to the invention are. The modification can be carried out at any point in time after the formation of the isocyanate groups by phosgenation take place, d. H. even before trimerization, but in this case it should be noted that the weight of the non-volatile by-product is the weight determined for the unmodified mixture. the Modification is often due to the improved physical properties, e.g. B. the reduced The tendency to crumble, which can be achieved in the foams formed, is preferred.

These mixtures can also contain conventional additives, e.g. B. flame retardants, such as organic Phosphates and antimony trioxide, and stabilizers, e.g. B. hindered phenols and trialkyl phosphites, contained and in suitable solvents, e.g. B. methylene chloride, trichlorofluoromethane and dichlorodifluoromethane, be solved. Of course, these materials that do not contain isocyanate groups will not regarded as the basis for the above calculations. Common propellants can be used, e.g. B. Water, d. H. the carbon dioxide formed by the reaction of water, or volatile liquids, z. B. the above solvents. See Chapter 8 of "High" for more details on this Polymers ”by Saunders and Frisch, Volume XVI, Polyurethanes: Chemistry and Technology, Interscience Publishers, New York.

The isocyanate mixtures are suitable for numerous common uses. However, as the examples show they can be put together in such a way that hard foams are obtained that can be stuck without burning Can be demolded quickly, an advantageous compressive strength and dimensional stability over a wide area Temperature range for a given volume weight and surprisingly good insulation (lower

■> K-factor) with low density. the Foams are therefore likely to be valuable for insulation, for example in refrigeration technology and for Pipelines and tanks, and in the construction sector.

ίο In the following examples all relate Quantities are based on weight, unless otherwise stated. The following isocyanates were used:

Polyisocyanate A

An undistilled material that has an amine equivalent from about 95 to 100, contains about 85 to 90% volatile toluene diisocyanate (TDI) and otherwise consists of By-products of phosgenation and phosgenation of a mixture of 2,4- / 2,6-toluenediamine (80/20), which is dissolved in o-dichlorobenzene (ODCB), essentially to that in the US patent 28 22 373 described manner and subsequent removal of the o-dichlorobenzene by fractionation has been made.

Polyisocyanate B

A similar material that has an amine equivalent of

about 105 to 113, only about 75% volatile TDI

jo contains and is obtained by converting polyisocyanate A about half of the volatile TDI is removed by distillation.

Polyisocyanate C

A undistilled material which has an amine equivalent of about 140, contains about 72% 4,4'-diisocyanatodiphenylmethane (MDI) and is prepared as follows: 1 mole of aqueous formaldehyde is added to an aqueous solution of 3 moles of aniline and 2.8 mol of hydrochloric acid at about 3O ⁰ C, heated 3 hours at 85 ° C, neutralized with sodium hydroxide, the organic layer is separated and removed from unreacted aniline by distillation under reduced pressure, the residue obtained is 4,4'-diaminodiphenylmethane which contains about Contains 15% higher polyamines, this unconverted material dissolves in o-dichlorobenzene, phosgenated essentially in the manner described in US Pat. No. 2,822,373 and removes the o-dichlorobenzene by fractionation.

so The following analyzes and tests are used:

Isocyanate group content: ASTM D 1638-60 T;
the amine equivalents are based on this
Analysis.

Thermal conductivity (K-factor): ASTM C t77-45
Dimensional stability: ASTM D 794-49
Friability: ASTM C 421
Compressive Strength: ASTM D 1621-59T
Volume weight: ASTM D 1622-59 T
All densities given here apply to the core of the foams.

example 1

To 1750 parts of polyisocyanate B (—NCO content 37.4%) contained in a stirred vessel blanketed with nitrogen becomes about 12.8 parts

N-Ethy! Aziridine given. The temperature rises from about 25 to 66 ° C. After about 20 minutes, the liquid reaction mass thickens and the content of isocyanate groups falls to about 31.3%. Further trimerization is prevented by adding 17.5 parts of benzoyl chloride. The reaction mass is diluted by adding 1750 parts of polyisocyanate B and allowed to cool to about 25 ^° C. with stirring. The product obtained has a Brookfield viscosity of 1069 cP at 28 ° C. and an isocyanate group content of 33.85%, corresponding to an amine equivalent of 124. The reduction in the isocyanate group content corresponds to an isocyanate residue content of about 3.55%. The material contains the equivalent of about 25% non-volatile by-products of phosgenation.

A hard foam is made from the product of this example using the following approach manufactured:

Polyisocyanate

Part A

part B

93 pieces

Polyether polyol manufactured by

Oxypropylation of sucrose;

Hydroxyl number 470,

Equivalent weight 120,

Viscosity 22,000 cP at 25 ^° C .;

Amine nitrogen about 1.2%

(»Selectrofoam« 6406)
Surfactant and

Foam stabilizer: hydrolytic

stable block copolymer of

Polyoxyalkylene and

Polydimethylsiloxane, commercially

available as DC-195
N, N-dimethylethanolamine
Dibutyltin dilaurate
Trichlorofluoromethane

100 parts

2 parts

Part 1

0.1 part

40 parts

Parts A and B are mixed for about 12 seconds using a high-speed laboratory mixer. The mixture is poured into a suitable mold and left to foam. The foaming time, d. H. the Time it takes for the foam to reach its maximum height from the start of mixing, is 90 seconds. The foam obtained has a density of 26.1 kg / m *, a K factor of 1.35 kcal / h / mVC / cm and a friability of 27.4% according to ASTM C-421.

Essentially the same results are obtained when a foam is applied to the above described manner using 0.3 parts of a 33% solution of triethylenediamine in Dipropylene glycol is produced in place of 0.1 part of dibutyltin dilaurate.

The above values show that the foams made according to this example are low Volume weight but excellent thermal insulation properties and acceptable resistance to Have grind.

In a comparative experiment which was not carried out in accordance with the invention, a hatter was found Foam prepared in the manner described above with triethylenediamine in dipropylene glycol, wherein But instead of the trimerized crude polyisocyanate

B 90 parts of a trimerized, refined 2,4 / 2,6-tolylene diisocyanate (80/20) were used which contained 4.8% isocyanurate residues and 43.5% isocyanate groups and had an amine equivalent of 97. The comparison foam had a comparable density of 24.03 kg / m ^3, but a worse K-factor of 1.612 kcal / h / m ^2/0 C / cm and a friability of 53%.

Example 2

40 parts of N-ethyl aziridine are added to 5400 parts of a 4: 1 mixture of polyisocyanate A and polyisocyanate C (—NCO content of the mixture 39.8%), which is contained in a stirred tank covered with dry nitrogen. The temperature rises from about 25 to 83 ^° C. within about 1.5 hours. At this point in time, the reaction is terminated by adding about 50 parts of benzoyl chloride. 340 parts of polyisocyanate C and 1,360 parts of polyisocyanate A are added to 2700 parts of this material, which contains 31.7% of isocyanate groups. The resulting mixture is stirred until it is uniform. The diluted product contains 34.9% isocyanate groups, corresponding to an amine equivalent of 120. The reduction in the isocyanate group content corresponds to a content of isocyanurate residues of 4.9%. The dilute mixture contains the equivalent of about 13% non-volatile by-products of phosgenation.

Example 3

To 2000 parts of polyisocyanate A (—NCO content 43.1%) in an isolated, with dry nitrogen covered agitator container, about 16 parts of N-Ethylaziridine are added. You let them Trimerization proceed until the isocyanate group content is less than 32%. To this 300 parts of polyisocyanate A and 20 parts of benzoyl chloride are added. The product obtained contains 32.2% isocyanate groups corresponding to an amine equivalent of 130. The reduction in The isocyanate group content corresponds to an isocyanurate residue content of 10.9%. The material contains that Equivalent of about 12.5% non-volatile by-products of phosgenation.

To 100 parts of this material becomes about 15 parts Trichlorofluoromethane given. The mixture does not separate out solids when stored at around 5 ° C. A hard foam is made from the neat polyisocyanate mixture of this example using made using the following approach:

Polyisocyanate mixture

Part A

part B

Polyether polyol as in Example 1

described
Surface active agent, as in

Example 1 described
Ν, Ν-dimethylethanolamine
Trichlorofluoromethane

112 pieces

100 parts

2 parts
3.4 parts
72 parts

Parts A and B are mixed for about 4 seconds using a high-speed laboratory mixer. That

Mixture is poured into a suitable mold and left to foam. The foaming time is about 90 seconds. The foam has a density of 18.58 kg / m ³ and a factor of 1.77 kcal / h / m ² / ° C / cm. The compressive strength parallel to the impact is 0.7 kg / cm *, perpendicular to the impact 0.88 kg / cm ² .

The above values show that the foam produced according to this example is of low Volume weight has excellent compressive strength and thermal insulation properties. These are two very important properties for the use of hard

Foams. _. . . .
Example 4

To 2014 parts polyisocyanate A (-NCO content 42.4%), which in an isolated, with dry nitrogen covered agitator container, about 9 parts of N-Ethylaziridine are added. The trimerization is done about 6 hours. During this time the temperature rises from 25 to about 54 ° C. The reaction is stopped by adding 10.1 parts of benzoyl chloride. The product obtained contains 38.5% isocyanate groups corresponding to an amine equivalent of 109. The reduction in The isocyanate group content corresponds to an isocyanurate residue content of 4.3%. The material contains that Equivalent of about 12.5% non-volatile by-products of phosgenation.

Example 5

For 100 parts of polyisocyanate A there are 4.6 parts of a Given hexol, which has an equivalent weight of about 125 and the reaction product of 1,2-propylene oxide and is sorbitol. After the hexol has reacted, the modified polyisocyanate has an isocyanate group content of 38.8%.

0.052 parts of tetramethylguanidine are added to 52.5 parts of the modified polyisocyanate A, which is contained in an insulated stirrer vessel at 26 ^° C., over the course of 17 minutes. The polyisocyanate is left to trimerize for 12.5 hours. After this time the temperature has risen to 63 ° C. The trimerization is terminated by adding 0.255 parts of benzoyl chloride. The product obtained contains 33.9% isocyanate groups and has a Brookfield viscosity of about 1000 cP at 23 ^° C. The reduction in the content of isocyanate groups corresponds to a content of isocyanurate residues of 4.7%. The material contains the equivalent of about 12% non-volatile by-products of phosgenation.

A hard foam is produced from this polyisocyanate by a one-step process in which two sub-components are brought together continuously in a mixing head rotating at high speed will. The ingredients used and their proportions by weight are given below.

Current A (42 ⁰ C) 107 pieces Polyisocyanate mixture Stream B (22.5 ° C) 100 parts Polyol as described in Example 1 Surface active agent, as in 2 parts Example 1 described 2.4 parts N, N-dimethylethanolamine Triethylenediamine, 0.6 parts 33% in dipropylene glycol 71 pieces Trichlorofluoromethane

Apparatus suitable for metering and mixing these sub-components are in Du Pont Elastomer Chemicals Bulletin HR-32, "Metering and Mixing Equipment for the Production of Urethanes Foam Products ”by S. A. Steward, published by the applicant in September 1958, described.

The mixture discharged from the mixing head is poured into molds heated to 38 ° C and left to foam. The foaming time is 105 Se-K). The foam becomes so hard and tack-free in about 4 minutes that it can be removed from the mold. It has a volume weight in the core of 22.43 kg / m ³ and a compressive strength of 1.09 kg / cm ² perpendicular to the impact. The original K-factor is 139 kcal / h / mV ° C / cm. After aging for 30 days at 60 ⁰ C, the K factor is 1.76 kcal / hr / m ^2/0 C / cm. The foam friability as loss by ASTM C-421 is 8.7%. The foam has good dimensional stability, visible fact that its dimensions do not change after one day at -26 ° C and its linear dimensions after 7 days at 100 ⁰ C to increase by 5%.

The above values show that the foam made according to this example is a low one Has density, but has high compressive strength, good thermal insulation and good dimensional stability The foam also shows good resistance to attrition.

_{J ()} example 6

0.253 parts of tetramethylguanidine are added to 494.5 parts of polyisocyanate A (—NCO content 42.1%). The mixture is stirred under dry nitrogen in an isolated reaction vessel.

J5 temperature of 26 ° C increases within 48 hours to 63.7 ° C, and the isocyanate group content falls to 36.8%. At this point the calculated Isocyanurate residue content 5.3%. The trimerization is achieved by adding 1.23 parts of benzoyl chloride

-to canceled. To the trimerized crude polyisocyanate 21.0 parts of a hexol are added which has an equivalent weight of about 125 and the product the reaction of 1,2-propylene oxide with sorbitol is after the reaction of the hexol with the polyisocyanate contains 33.9% isocyanate groups. she has a Brookfield viscosity of 908 cP at 23 ° C. The content of cyanurate residues in this material is 5.1%, corrected for the addition of the polyol. This material contains the equivalent of about 12% non-volatile

so by-products of phosgenation.

The material is essentially the same

Properties like the polyisocyanate mixture prepared according to Example 5. The only major under-

'Difference in the making is the order in which the Modification with the polyol and the trimerization can be carried out. When used to manufacture a hard foam in the usual way, as described in Example 5, with the polyisocyanate mixture of this example are essentially the same

bo results obtained for the product according to Example 5 are given.

Example 7

A solution of 10 parts of the trimer of refined 2,4-tolylene diisocyanate in 90 parts of polyisocyanate A is used to make a rigid polyurethane foam that is used Trimers is essentially based on that in Example 5 of the

US Pat. No. 2,801,244 prepared in the manner described and contains 24.6% isocyanate groups. The solution contains about 1% byproducts of phosgenation and about 2.4% isooyanurate residue and has an amiri equivalent of *, 03.

A foam is prepared as follows: 96.2 parts of the solution described above are mixed with 156 parts of a foam premix which is commercially available under the name "Selectrofoam" 6528 and a mixture of about 75% of a polyether polyol intended for hard foams with an equivalent weight of about 120 and about 25% trichlorofluoromethane. It is believed that the premix also contains small amounts of catalysts for polyurethane foams and a polyoxyalkylenepolydimethylsiloxane surfactant. After a mixing time of 10 seconds, the mixture is poured into suitable containers and allowed to foam. The foaming time is 110 seconds. The foam is tack-free after 130 seconds. The foam is left to stand for about a day and then has a density of 24.83 kg / m ³ , a K factor of 1.48 kcal / h / in ² / "C / cm, a friction loss of 37.5% and a Compressive strength of 1.72 kg / cm ² parallel to the impact. The foam has good dimensional stability, which results from the following values:

7 days at 100 ^° C
7 days at -26 ° C

7 days at 38 ° C and 100%
relative humidity

Volume increase 5%

no

Volume change

Volume increase 5.5%

Example 8

A solution of 26.6 parts of the trimer of 2,4-tolylene diisocyanate described in Example 7 in 79.5 parts of a polyol modified crude toluene diisocyanate is used to make a hard one The modified diisocyanate is the product of the reaction of 100 parts of polyisocyanate A and 4.6 parts of a hexol, which by condensation of propylene oxide with sorbitol to form a Product that has an equivalent weight of about 125, The solution obtained contains about 9% by-products of phosgenation, about 6% Isocyanurate residues and has an amine equivalent of about 118.

About 106 parts of the solution described above are mixed for about 10 seconds with 150 parts of the foam premix described in Example 7. The mixture obtained is poured into suitable containers and left to foam. The foaming time is 110 seconds. The foam is tack-free after 120 seconds. After standing for about 1 day, it has a density of 26.43 kg / m ³ and the following excellent physical properties:

K factor

Friability

Compressive strength

Dimensional stability

14 days at 37.8 ° C and 100%
relative humidity
14 days at 100 ^° C

1.39 kcal / h / mV ° C / cm
32.8% loss
1.69 kg / cm ² parallel
to blow

Volume increase 7.5%
Volume increase 3.5%

Example 9

A crude tolylene diisocyanate modified with polyol is made by reacting 100 parts of polyisocyanate A and 4.6 parts of the hexol described in Example 8 prepared The modified with the polyol crude tolylene diisocyanate, which contains 38.4% isocyanate groups contains is trimerized by adding about 1.1% N-phenethylaziridine can be added within 2 hours.

ίο During the addition, the temperature of the crude diisocyanate rises from 24.5 to 110 "Q. After the addition, the trimerization is terminated by adding 1% benzoyl chloride, based on the initial weight of the diisocyanate. This product contains 28.6% isocyanate groups. Es is diluted with the same amount by weight of the above-described, polyol-modified polyisocyanate A, whereby the content of isocyanate groups increases to 32.7% has an amine equivalent of 128 J5.

To the properties and suitability of an isocyanate mixture according to this example and a known one To compare raw isocyanate for the production of hard foams, are machine-mixed Foams made from the polyol-modified polyisocyanate A and the trimerized raw mixture made in the manner described in this example. To compare the two raw

jo isocyanates to allow the same percentage of the blowing agent (20%), based on the total weight of the batches for the foam, used The same —NCO / OH ratio (1.05 / 1.0) applied.

The composition of the approaches, the foam properties and the properties of the product The foams obtained are summarized below

Trimer Polyolnodi- ized fied product Polyisocyanal A ·)

Current A

Polyisocyanate, parts

Stream B

Poyol as in Example 1
described, parts

Dimethylethanolamine, parts
Triethylenediamine, 33% in
Dipropylene glycol, parts
Surface active agent
as described in Example 1, parts

Trichlorofluoromethane, parts
Foaming time, seconds
Total volume, kg / m ³

Vertical compressive strength
for impact, kg / cm ²

K factor, kcal / h / m ² / ° C / cm
Friability,% loss

111.3 92.0

100.0 100.0

3.4
0.6

2.0

3.4
0.6

2.0

54.2 49.6 71 90 31.08 32.36 1.29 1.07 1.44 1.49 13.0 25.5

*) Outside the scope of the invention, only zui Comparison included.

809 533 /

The trimerized product reacts faster than that Foaming time shows In addition, the foam produced from the trimerized polyisocyanate was despite a lower spatial weight in all measured Properties superior.

All of the final mixtures of isocyanates described in the examples have an average overall functionality of at least 2.0 isocyanate groups, and the isocyanurate-containing monomers and polymers have an average functionality of at least about 1.5.

Claims (3)

Patent claims: 1. Mixtures based on aromatic polyisocyanates, characterized by 1. an amine equivalent of 103 to 130 2. an average functionality of at least two isocyanate groups and 3. a content of 9 to 25% of non-volatile ι ο phosgenation by-products and of 2.4 up to 10.9% of isocyanurate residues which have an isocyanate group functionality in aromatic isocyanate trimers of at least 1.5 are included, with all information on the free Molecules containing isocyanate groups are related.