DE1921952C3 - Process for the production of optionally foamed polyurethanes - Google Patents

Description

O = V (OR) ₃

or

(ROj ₂ -VrO-V-OR

QV (OR) ₂

used in which the radicals R are branched or unbranched alkyl radicals with 1 to 5 carbon atoms, which are optionally interrupted by an oxygen atom between two carbon atoms, or cyclohexyl or phenyl radicals and η is a number between 0.2 and 10.

30th

It is known. Polyurethanes by reacting polyols with polyisocyanates using the isocyanate polyaddition process to manufacture. The following substances, for example, are suitable as polyols: polyethers, Polythioethers, polyesters, polyesteramides and polyacetals. As polyisocyanates, most of today's can known types, preferably di- and triisocyanates, are used.

Either the so-called "one-shot process" or the "prepolymer process" is used for the polyaddition to use.

It is also already known, the reaction of the isocyanate groups with the active Η atoms of the Accelerate polyols with catalysts. The catalytic effect of tertiary amines known. In addition to the tertiary amines, there are also organic metal compounds such as Tin (ll) octoate and di-n-butyltin dilaurai, use as catalysts. There is also one related to this catalytic effect of organic metal compounds known, which apart from an alcoholic Bond of the metal to the organic radicals still contain a coordinative bond. Such chclate compounds are for example the acetylacctonates of zirconium, vanadium and titanium.

However, all of these known catalysts still have disadvantages. This is the case with many, for example The activating effect of the catalysts is insufficient. Acetylacetonates are ho in some reaction systems not or only insufficiently soluble, so that a catalytic effect is largely absent.

It is also already known that the Production of foams based on polyester-polyisocyanate, in the case of water as a foaming agent (> < and a tertiary amine can be used as an activator. the pore structure of the foam by adding Zirconium alcoholates, which are derived from long-chain alcohols with at least 6 carbon atoms. can have a beneficial effect.

From FR-PS 12 40 863 it is known to contain urethane groups Foams made from polyether polyols and polyisocyanates in the presence of water, tertiary Amines and non-basic organometallic compounds, e.g. B. vanadium glycolate to produce. As it is at If the compounds mentioned are weak catalysts, tertiary amines must also be used will. In the absence of tertiary amines, no usable foam is formed.

From GB-PS 9 69 992 it is known as catalysts in the production of non-foamed thermoplastic polyurethanes vanadyl acetylacetonate, vanadium acetylacetonate, vanadium acetate, propionate, butyrate, benzoate, phthalate and adipate use which are relatively weak catalysts. In the task which this British patent application is based, namely to produce elastomeric polyurethanes, which up to a thermoplastic To react to the state and to be able to reshape it into a desired final shape, it is understandable that only weak catalysts can be used. They become strong catalysts is used, it is difficult to stop the reaction at the thermoplastic stage.

Vanadium alcoholates are used as crosslinking agents for curing of according to GB-PS 8 69 606 Fibers applied or formed on fibers binders used, which by reaction of a organic compound with at least two NCO groups with a monomeric ester in his Molecule contains at least two OH groups. Such vanadium compounds are but extremely difficult to access. In particular, the pure display causes great difficulties. you are therefore cannot be used in practice.

It has now been found that in the production of optionally foamed polyurethanes from polyols and polyisocyanates in the presence of vanadyl alcoholates or phenolates of the following Type with the exclusion of water a catalytic effect on the polyaddition reactions occurs, which is much stronger than the effect of all previously known catalysts.

The invention thus relates to a process for the production of optionally foamed polyurethanes by reacting polyisocyanates with polyols in the presence of vanadium catalysts with the exclusion of water. The process is characterized in that the vanadium catalysts in organic vanadium compounds of the general formula which are soluble in the reaction mixture

O V (OR),

(RO), - V-f-O - V -

OR

-O - V (OR),

used, in which the radicals R are branched or unbranched alkyl radicals with I to 5 carbon atoms, which are optionally interrupted by an oxygen atom between two carbon atoms, or

_lheX y | - or phenyl radicals and η a number

en is 0.2 and 10.

For the purposes of the invention, polyols are preferably tolyether polyols with a vanate functionality ^{of 2 to 9 and a} hydroxyl number of 600. Such polyether polyols can be prepared from polyhydric alcohols with alkylene oxides. As polyhydric alcohols, for example glycerol, trimethylolpropane, pen- ^^ hrite, sorbitol, glucose and sucrose can be used. Suitable alkylene oxides are, as examples ■ Lpylenoxid, 1.2-, ¹ -., ^{3 "and} 2,3-epoxybutane may be mentioned styrene oxide and epichlorohydrin Mixtures of these alkylene oxides containing up to 30 weight percent Athylenrid be used The reaction may be catalyzed by bases.. preferably, however, foWätherpolyole be used which have been obtained by such a reaction under acid catalysis, such as, for example, _using boron trifluoride. Characteristic of such polyether polyols is that they ben secondary OH groups, a considerable amount of primary OH Groups included.

A preferred production method for this is described in GB-PS 10 16 589, for example. at the sucrose-based polyols used according to the invention one can of course ultimately assume strength, which, as is well known, easily converts into the mono- or can convert oligosaccharides.

Polyethers can also be used as polyols for the purposes of the invention, which are obtained by addition of Alkylene oxides are produced from ethylenediamine and / or diethylenetriamine or polyesters with terminal ends OH groups. for example those based on adipic acid-ethylene glycol.

Finally, as polyhydroxy compounds are according to the invention also polyethers, such as those produced by the polyaddition of epoxy compounds Water can be obtained to use.

Examples of these are polyethylene oxide, polypropylene oxide and poly-1,2-butylene oxide and polyepichlorohydrin. Polybutylene oxide can also be obtained by polymerization can be obtained from tetrahydrofuran.

In the polyols obtained according to GB-PS 10 16 589 and other polyether polyols are the Most of the catalysts in the form of acetylacetonates or chelates are insoluble or only insufficiently soluble. while the vanadium catalysts used according to the invention are readily soluble therein.

According to the invention, all polyisocyanates customary in polyurethane technology can be used as polyisocyanates. Di- and triisocyanates are preferred. Aliphatic and aromatic, di- and polyvalent isocyanates are suitable, such as, for example, alkylene diisocyanates, such as tetra- and hexane-ethylene diisocyanate, arylene diisocyanate and their alkylation products, such as m- and p-phenylene diisocyanate, naphthylene diisocyanate. Diphenylmethane diisocyanate. Tolylene diisocyanates. such as 24- and 2,6-toluylene diisocyanate and their mixtures, di- and triisopropylbenzenedusocyanate and triphenylmeihane triisocyanate, aralkyldnsocyanates such as 1- (isocyanatophenyl) ethyl isocyanate or m- and p-xylylene diisocyanate, as well as alkoxy-, aryloxy-, -NO ₂ - and -Cl groups-substituted polyisocyanates of the types listed above, such as polyphenylpolymethylene polyisocyanate, which is obtained by aniline-formaldehyde condensation and subsequent phosgenation, also the reaction products of the above-mentioned polyisocyanates with a deficit of polyhydroxy compounds, such as trimethylolpropane, hexanetriol, Glycerine and butanediol In addition, polyisocyanates blocked by phenols or bisulfite, for example, and polymerized isocyanates with an isocyanurate ring structure can be used.

According to the invention, it is preferred to work in such a way that only the polyols are reacted with the polyisocyanates will.

ίο The quantity ratio is chosen so that on a hydroxyl group comes to about 0.4 to 2.0 isocyanate groups «. Preferably should be on a hydroxyl group about an isocyanate group. The water-free polyol is used at room or outside temperature the polyisocyanai and the vanadium catalyst and optionally with fillers and / or surface-active Substances and optionally mixed with propellants. The resulting reaction mixture can one z. B. react in a form.

In principle, known crosslinking agents such as glycol and Butanediol, can be used. In this case one works either according to the »one-shot method« or according to the "prepolymer process". The proportions the reactants often have to be modified in this way of working. You can however, they can easily be determined in preliminary tests. In general, the polyisocyanate will be referred to on the higher molecular weight polyol in excess, but apply the crosslinking agent in deficit.

According to the invention, for example, vanadyl triisopropoxide, vanadyl tri-n-butoxide, Vanadyl triisoamylate, vanadyl tri-tert-butylate, vanadyl tricyclohexanolate and vanadyl triphenolate. Also the corresponding reaction products of the vanadyl alcoholates with water with the escape of alcohol are suitable.

The vanadium catalysts used according to the invention must be soluble in the reaction mixture. The high activity of the vanadium catalysts used according to the invention initially results the advantage over previously known catalysts that smaller amounts of these catalysts need to be used to achieve the same effect. In the inventive It is sufficient for the method to use the vanadium catalysts in an amount of 0.001 to 1.0 percent by weight, preferably 0.005 to 0.1 percent by weight, based on the polyol used in each case. Another advantage of the vanadium catalysts used according to the invention is that the polyaddition runs off completely and thereby won polyurethanes which are characterized by excellent mechanical properties.

If the process according to the invention is used in the casting of polyurethanes, this is evident in addition, that the dissipation of the heat of reaction proceeds very favorably even in the case of thick-walled shaped bodies. Man comes to materials that are free of streaks and are homogeneous. That too contributes to the training of good ones mechanical properties such as high breaking strength and tensile strength. The good modulus of elasticity is special and to highlight the high impact strength. Furthermore, the reaction runs faster than when using the 65 known catalysts. The increase in the reaction speed and thus the shortening the demolding times are very considerable.

In the manufacture of flat structures such. B. from

Foils or films, according to the method according to the invention, there is still another advantageous one Effect Such flat bodies based on polyurethane generally have an irregular shape and surface containing bubbles. This is not always just due to the moisture content of the starting products attributed to the polyurethane, but has its cause in many cases also in the water content of the surrounding air The water reacts with isocyanate groups in the surface layers of the reaction mixture, and such a disturbing reaction is known to result in the development of CXh and the formation of bubbles. In which According to the process according to the invention, the presence of the vanadium catalysts leads to such an acceleration the reaction between the polyisocyanate and the polyol, that with it the reaction of the humidity cannot compete with the isocyanate groups. There is no formation of bubbles. The slides and films therefore have a uniform, smooth surface. It can also be observed that the stickiness of the Surface has disappeared after a very short time.

If foamed polyurethanes are to be produced, the reaction mixture is put in per se organic blowing agents, preferably haloalkanes, which can be evaporated in a known manner at the reaction temperature or -alkene, too. The following substances, for example, can be used as haloalkanes or haloalkenes Question: trifluoromethane, chlorodifluoromethane, dichlorodifluoromethane, 1,1-dichloroethylene and trichlorethylene. The propellant is usually mixed with one of the reactants, preferably the polyol, before the final reaction mixture is made. They are usually used in foam production Cell regulators, stabilizers and optionally emulsifiers added. Suitable cell regulators are, for example to mention organic silicon compounds.

With regard to the production of polyurethane casting compounds and foams, reference can be made to the following literature be pointed out:

1. Saunders-Frisch, "Polyurethanes: Chemistry and Technology", Parts I and II, Inlerscience Publishers, 1962 and 1964,

2. Vieweg-Höchtlen, "Kunststoffhandbuch", Volume VII, Hanser-Verlag. 1966.

Compared to known foaming processes, the foaming process according to the invention has a special feature, which is particularly advantageous in the manufacture of hard foam. This is because organic tin catalysts are used in one case, but those according to the invention in the other Vanadium catalysts used in each case used in such a concentration that the beginning of the If foaming occurs after mixing the reactants at the same time (same foam point), it falls in the first case the time between the foam point and the solidification of the foam (gel point) much shorter than in the last case. A long period of time is very desirable in that the rigid foam is on maximum volumes can be driven and thus, for example, when applying thermal insulation layers the space provided for foaming is optimally filled. will. An extension of the The time mentioned can be used in the known processes in which organotin catalysts are used Come application, although achieved by using less of these catalysts. Practical but one cannot proceed in this way, since this would result in the

45 beginning of foam formation (the foam point) is shifted very strongly. This would make the process too inefficient.

The extension of the time span between the foam point and the gelling point when using the invention The process also has a particularly favorable effect than the resulting one Rigid foam has a very homogeneous pore structure. The same favorable pore structure is obtained even if the foaming is carried out in a mold Process according to the invention also arrive at the so-called structural or integral foams, which for example in "Modern Plastics", Dec. 1968, pp. 69 bis 72, and in "British Plastics", January 1969, pp. 71 to 75, these integral foams have been described a pore-free, stable, enveloping polyurethane shell and are already of great importance in the Technology and for the furniture industry. Since the production of integral skin foams can only be efficient if the demolding times are short, the vanadium catalysts used according to the invention are used particularly valuable for this.

example 1

240g of a liquid polyol based on glucose-propylene oxide, as it has been prepared under acid catalysis according to GB-PS 1016 589, with an OH number of 269 were in a 1/2-1 stirred vessel with 24 g of a 50 percent by weight zeolite Dispersion in castor oil added. The mixture was then ^{heated to 100 °} C. with stirring and at the same time the pressure in the reactor was reduced to about 10 mm Hg. These reaction conditions were maintained for 3 hours. The mixture was then cooled to 25 ° C. and the pressure was then increased again to normal pressure

181.5 g of the homogeneous, liquid product were withdrawn from the reactor, into a 500 ml beaker given and mixed with 0.022 g of vanadyl triisopropoxide and this dissolved with stirring.

With further intensive stirring, 118.6 g of a highly viscous, solvent-free polymethylene polyphenyl isocyanate were finally obtained Poured into the beaker having a molecular weight of about 390 and an isocyanate content of about 32 weight percent. To The polyaddition started for a short time with development of heat. The mixture was immediately put into molds Cast for test bars measuring 10 χ 15 χ 120 mm. The crowd was 30 minutes after Admixture of the polyisocyanate solidifies. The bars were removed 60 minutes after casting and heated in a drying oven to 110 ° C for 3 hours.

The next day the bending test according to DIN 53 452, the impact bending test according to DIN 53 453 and the Test for dimensional stability under heat according to DIN 53 461 carried out. The following values were obtained (Mean of 5 individual measurements):

Flexural strength

Ε module (from bending test

based on the

Hook's Law)

Impact strength

Dimensional stability

in the warmth

900 kg / cm *

27,000 kg / cm ²
34.6 kgf cm / cm ²

48 ° C

Comparative example 1

In a second approach, the procedure was as in Example 1, with the difference that instead of 0.022 g of vanadyl triisopropoxide, 0.98 g of dibutyltin dilaurate was added to the reaction mixture as a catalyst. In this way it was achieved that the gelation time was about 30 minutes in this batch as well. The resulting castings
DlN regulations checked,
were the following:

Flexural strength

Modulus of elasticity

Impact strength

Dimensional stability

in the warmth

were after the same The test results

730 kg / cm ²
23 300 kg / cm ²
16.1 kgf cm / cm ²

47 ° C

Examples 2 to 7
and Comparative Examples 2a to 7a

The procedure was as in Example 1, but in some cases with different starting materials. So came partially instead of the polyol based on glucose-propylene oxide with an OH number of 269 polyols

Table 1

Use, which were obtained in an analogous manner and had OH numbers of 314 or 210. The In some experiments, polymethylene polyphenyl isocyanate was replaced by a liquid, solvent-free.

4,4'-diphenylmethane diisocyanate containing higher functional isocyanates replaced. Each experiment was carried out once with vanadyl triisopropoxide and once with dibutyltin dilaurate (comparative examples) as the catalyst accomplished. The amount of each

ίο catalyst was chosen so that the gel time of the reaction mixture was about 30 minutes. The polyurethanes were again according to those in Example 1 mentioned regulations.

The flexural strengths and impact strengths corresponded approximately to the values from Example 1. In contrast, the Values for the Ε module in the case of using vanadyl triisopropoxide are consistently much higher. the Values are compiled in Table 1. When assessing the test results, it is particularly important to Note that the amount of dibutyltin dilaurate used was significantly greater than the amount of Vanadyl triisopropoxide.

example
Iff * J ^ f ^^ *> Polyisocyanate Crowd on tack free.
\ l 0 rL "1 \ T *" »i Polyol catalyst Amount of Ge Modulus of elasticity and Ver
at the same time based 181.5g polyol OH number Type*) weight percentage, game no. related to G the polyol 137.6 0.013 kg / cm ² 2 Diphenylmethane-4,4'-diisocyanate 137.6 314 V 0.034 29 400 2a Diphenylmethane-4,4'-diisocyanate 118.6 314 Sn 0.012 24 600 3 Diphenylmethane-4,4'-diisocyanate 118.6 269 V 0.054 26 400 3a Diphenylmethane-4,4'-diisocyanate 100.0 269 Sn 0.007 25,000 4th Diphenylmethane-4,4'-diisocyanate 100.0 210 V 0.037 17,000 4a Diphenylmethane-4,4'-diisocyanate 137.6 210 Sn 0.006 14,000 5 Polymethylene polyphenyl isocyanate 137.6 314 V 0.170 29 500 5a Polymethylene polyphenyl isocyanate 118.6 314 Sn 0.012 26,000 6th Polymethylene polyphenyl isocyanate 118.6 269 V 0.168 23,000 6a Polymethylene polyphenyl isocyanate 100.0 269 Sn 0.012 21000 7th Polymethylene polyphenyl isocyanate 100.0 210 V 0.180 16 400 7a Polymethylene polyphenyl isocyanate 210 Sn 5 700 ·) V = vanadyl propylate. Sn = dibutyltin dilaurate. The rise time was only 95 seconds. the
ιτίϊτ Hot * QtPifT7Ait wr it * L · to pir * h ci / "* Vi in flor Waica Example 8

50 g of a liquid polyol based on sorbitol propylene oxide, with an alkaline catalysis, with an OH number of 480 were intimately mixed with 1 g of an oxyalkylated polysiloxane, 18 g of trichlorofluorine and 0.5 g of vanadyl triisopropoxide Diphenylmethane ^ '- diisocyanate base, as used in Example 2, was added to this mixture with vigorous stirring . Foaming started after 32 seconds. 80 seconds after the addition of the polyisocyanate, the surface of the foam body was tack-free. 1 ¹ O seconds after the addition of the polyisocyanate was observed, no further expansion of the foam body more; the rise time was therefore 110 seconds.

Comparative example 8

The procedure was as in Example 8, with the difference that instead of 03 g of vanadyl triisopropoxide, 0j6 g of di-n-butyltin dilaurate were used.

The foam point (start time) was 35 seconds. Already 60 seconds after mixing , the surface was such that the final volume of the foam body in an L-shape was considerably smaller than in Example 8.

Examples 9 to 29

and Comparative Examples 9 to 15

In the following experiments, a liquid product based on glucose-propylene oxide was used as the polyol, as is produced under acid catalysis according to GB-PS 10 16 589. It had an OH number of 314. As in Example 1, dehydration was carried out using a zeolite. Further processing to the polyurethane also took place as in Example 1. However , instead of vanadyl triisopropoxide, other catalysts were sometimes used and the proportions were changed.

Table 2 shows the gel times and temperatures as a function of the respective amount of catalyst compiled. From these values it can be seen that the vanadium catalysts used according to the invention are considerably more active than the known catalysts are.

609 6S3 99

ίο

Table 2

Examples & Catalyst Amount, related Gel time Gelling Comparative type on the polyol tempe- examples Weight percent ralur No. min ⁰ C

9 Vanadyl tri-n-butoxide 10 Vanadyl tri-n-butoxide 11th Vanadyl tri-n-butoxide 12th Vanadyl tri-isobutylate 13th Vanadyl tri-isobutylate 14th Vanadyl tri-isobutylate 15th Vanadyl tri-tert-butoxide 16 Vanadyl tri-tert-butoxide 17th Vanadyl tri-tert-butoxide 18th Vanadyl tri-isopropoxide 19th Vanadyl tri-isopropoxide 20th Vanadyl tri-isopropoxide 21 22nd Vanadyl tricyclohexanolate 23 Vanadyl tricyclohexanolate 24 Vanadyl tricyclohexanolate 25th Vanadyl trimethyl glycolate 26th Vanadyl trimethyl glycolate 27 Vanadyl trimethyl glycolate 28 Vanadyl triphenolate 29 Vanadyl triphenolate 9 *) Dibutyltin diversatate 10 Dibutyltin diversatate Π Dibutyltin dilaurate 12th Dibutyltin dilaurate 13th Lead octoate 14th Lead octoate 15th without a catalyst

0.007
0.014
0.042
0.007
0.014
0.042
0.007 0.014 0.042 0.007 0.014 0.042

0.007 0.014 0.042 0.007 0.014 0.042 0.014 0.042

0.014
0.042
0.014
0.042
0.014
0.042

48
27
11th
54
29
11th
65
33
12 48 28
10

50
26th
11th
59
30th
12th
54 25

121

137

137

137

137

59 62 70 57 74 63 57 62 73 56 56 58

62 64 75 40 60 60 53 68

35 42 36 42 36 30 30

*) This compound is derived from a mixture of organic acids of the general formula

R ¹ i Ch, -C-COOH

! I.

R ²

in which R ¹ and R- 'represent alkyl radicals having a total of 7 carbon atoms.

Examples 30 and 31 serve to demonstrate the technical progress of the vanadium catalysts used according to the invention compared with the vanadium catalysts known from FR-PS 12 40 863 and GB-PS 9 69 992.

B ice ρ ic 1 30

The catalytic effect of vanadium glycol ·. the formula

O = V- (OCHj-CH ₂ O) ₁ = O -V

was compared with the inventive set / ten vanadium catalysts Vanadyltriisopropylat, Va nadyitrimethylglykolat of the formula

O = V (OCH ₂ -CH ₂ OCH,),

and vanadyl-n-butylate (partially con & ensified. Density Ό ²⁰ = 1,092. V content: 39%). It was found that vanadium glycolate of the formula

O = V (OCH ₂ -CH ₂ O) ₁ -V = O

a) On the basis of the following recipe, a non-foamed polyurethane was produced according to Example 1:

100 parts by weight of polyether polyol based on glucosc-propylene oxide, dehydrated with zeolite, prepared according to GB-PS 10 16 589 under acid caialysc. with an OH number of 300.

0.2 part by weight of non-ionic defoamer.

75 parts by weight of polymethylene polyphenyl isocya nat

0.02 parts by weight of catalyst.

The following compounds were used as catalysts gene used and compared their gel times in minutes.

catalyst

1. Without

2. Vanadyl triisopropoxide

not at all catalytic in anhydrous systems fts 3. Vanadyltrimethylglycolate works, both in the production of 4. Vanadyi-tri-n-butvJat (partially condensed) foamed as well as in the production of 5. vanadium glycolate of the formula non-foamed polyurethanes O = V- (OCHj-CHjO) J-V = O

Gel time in minutes

103 27 28 4b

101

b) According to the following recipe, a foamed Polyurethane made:

100 parts by weight of polyether polyol made from glucose and propylene oxide (OH number 510),
2 parts by weight of silicone oil,
1.6 parts by weight of catalyst, 38 parts by weight of trichlorofluoromethane, 134.8 parts by weight of solvent-free, higher-functionality isocyanate-containing 4,4'-diphenylmethane diisocyanate.

The following results were achieved:

catalyst

Start time rise time

Foam structure

1. Without 10 min

2. Vanadyl triisopropoxide 28 see

3. Vanadyl Trimethyl Glycolate 52 see

4. Vanadium glycolate of the formula

O = V (OCH2-CH2O) 3-V = O 10 min

90 see
200 see

Well
Well

The above experiments show the superiority of the vanadium catalysts used according to the invention compared to the prior art vanadium glycolate. So shows the vanadium glycolate no catalytic effect whatsoever in anhydrous systems.

The vanadyl tri-n-butoxide (partially condensed) used in example 30a under item 4 was as follows manufactured:

858.0 g VO (Ji-OGiHq) ₃ (= 3 mol) in a three-necked flask containing 500 ml of anhydrous n-butanol diluted While stirring g (= 2 mol) of water was added dropwise slowly at 40 to 6O ⁰ C 36.0 that the cloudiness that forms when the drops are added can constantly dissolve again. This is done with a reflux condenser attached. After all the water has been added, the mixture is heated to the boil. ^{The n:} butanol used as solvent is then distilled off in vacuo using a rotary evaporator. The residue is a clear yellow liquid with the density D ²⁵ = 1.092 of the formula

40

QH ₉ OVOVOV-OC ₄ H ₉
OC ₄ H, OC ₄ H ₉ OC ₄ H ₉

The V content is 39.0%; the degree of condensation is 2.0.

Example 31

In another experiment, the catalytic properties of vanadyl acetylacetonate were vanadium acetylacetonate and vanadyl acetate (GB-PS 9 69 992) with the catalyst used according to the invention vanadyl tri-isopropoxide compared.

a) Non-foamed polyurethanes were produced on the following basis:

100 g of a liquid polyol manufactured by acid-catalyzed reaction of glucose and propylene oxide (OH number 300) with a content of 5% zeolite as a drying agent,

72.6 g of diphenylmethane ^^ 'diisocyanate.

0.2 g non-ionogenic defoamer.

X g of a vanadium catalyst.

The starting materials were mixed in a beaker and poured into molds at room temperature. Ks Test bars measuring 10 15 χ 120 mm were created.

After the moldings had hardened, they were removed from the mold and ^{cured at 110 °} C. for 3 hours. The next day, the impact strength of the molded parts was measured in accordance with DIN 53 453.

It was found that 0.02 g of the vanadyl triisopropoxide used according to the invention had a strong catalytic effect; a 50-fold amount (X = 1 g) of vanadyl acetylacetonate, vanadium aoetylacetonate and vanadyl acetate was almost catalytically inactive. In addition, the impact strength of the molding produced with the vanadyl triisopropoxide was significantly higher.

The results are summarized in the following table:

catalyst crowd Gelation Impact (in g) time ability (in min) (kpcm / cm ² ) 1. Without 0 90 10.0 2. Vanadyl triisopropoxide 0.02 21 24.0 3. Vanadyl acetylacetonate 1.0 85 8.0 4. Vanadium acetylacetonai 1.0 80 8.8 5. Vanadyl acetate 1.0 90 12.1

b) Foamed polyurethanes were produced according to the following recipe:

100 g of a liquid polyol produced by alkaline catalyzed reaction of sorbitol with propylene oxide (OH number 510),

0.9 g of a vanadium catalyst, 1 g of hydroxyalkylated polysiloxane, 18 g trichlorofluoromethane,

64.8 g diphenylmethane ^^ '- diisocyanate.

The starting materials were mixed homogeneously and placed in a beaker. The following results were achieved:

catalyst Start time rising line

1. Without> 10 min -

2. Vanadyl triisopropoxide 34 see 125 see

3. Vanadyl acetylacetonate> 10 min -

4. Vanadium acetylacetonate> 10 min -

5. Vanadyl acetate> 10 min -

These results show that only the catalyst used according to the invention {vanadyl triisopropoxide has good catalytic efficiency. The known vanadium catalysts show no catalyzation table activity, and they do not produce foam.

Claims (1)

Claim: Process for the production of optionally foamed polyurethanes by reacting Polyisocyanates with polyols in the presence of vanadium catalysts with exclusion of water, characterized in that there is used as vanadium catalysts in the reaction mixture soluble organic vanadium compounds of general formulas