Production of low-fogging polyurethane foams, and specific poly-oxyalkylene-polyols which can be used for this purpose

The invention relates to a process for the production of polyurethane foams by reacting PA1 a) at least one organic polyisocyanate with PA1 b) at least one polyalkylene-polyol (b1) having a hydroxyl number of from 30 to 500, obtainable by alkoxylation of at least one initiator molecule from the group consisting of N,N'-bis(3-aminopropyl)ethylenediamine, tripropylenetetramine and tetrapropylenepentamine using at least one alkylene oxide, preferably ethylene oxide and/or 1,2-propylene oxide, or mixtures of the polyoxyalkylene polyols (b1) and other polyhydroxyl compounds having a functionality of from 2 to 8 and a hydroxyl number of from 15 to 500, and PA1 c) if desired, chain extenders and/or crosslinking agents, in the presence of PA1 d) blowing agents and, if desired, PA1 e) catalysts and PA1 f) additives, and to the novel polyoxyalkylene-polyols (b1) which can be used for this purpose.

The present invention relates to a process for the production of 
polyurethane foams, also abbreviated to PU foams below, preferably 
semirigid or rigid PU foams which have an improved foam structure, good 
aging properties and very good flow properties of the foamable reaction 
mixture and which are low-fogging, by reacting organic polyisocyanates (a) 
with polyhydroxyl compounds (b) and, if desired, chain extenders and/or 
crosslinking agents (c) in the presence of blowing agents (d) and, if 
desired, catalysts (e) and additives (f), where, according to the 
invention, the polyhydroxyl compounds (b) are polyoxyalkylene-polyols (b1) 
having a hydroxyl number of from 30 to 500 which are obtainable by 
polyaddition of at least one alkylene oxide, preferably ethylene oxide 
and/or 1,2-propylene oxide, onto at least one initiator molecule from the 
group consisting of N,N'-bis(3-aminopropyl)ethylenediamine, 
tripropylenetetramine and tetrapropylenepentamine, or industrially 
obtainable crude products thereof. 
The present invention furthermore relates to the novel 
polyoxyalkylene-polyols (b1) containing tertiary amino groups as bridges 
which can be used in accordance with the invention. 
The production of PU foams by reacting organic polyisocyanates with 
relatively high-molecular-weight polyhydroxyl compounds and, if desired, 
low-molecular weight chain extenders and/or crosslinking agents in the 
presence of catalysts and blowing agents and, if desired, additives and 
auxiliaries is known and is described in numerous patents and other 
publications. Reference may be made to the Kunststoff-Handbuch, Volume 
VII, Polyurethane, 1st Edition, 1966, edited by Dr. R. Vieweg and Dr. A. 
Hochtlen, Carl Hanser Verlag, Munich. 
Also known is the production of semirigid PU foams by the prepolymer 
process, usually from tolylene diisocyanate (TDI) prepolymers, and of 
semirigid and rigid PU foams by the one-shot process, advantageously using 
mixtures of diphenylmethane diisocyanates (MDI) and 
polyphenylpolymethylene polyisocyanates, known as crude MDI, as 
polyisocyanates. A specific selection of relatively high-molecular-weight 
polyhydroxyl compounds and chain extenders and/or crosslinking agents and 
various amounts of polyisocyanates and water allow semirigid and rigid PU 
foams having various mechanical properties to be produced by this process. 
Furthermore, semirigid PU foams can be produced without using water by the 
frothing process with the addition of dichlorodifluoromethane as blowing 
agent. The polyhydroxyl compounds used here are a combination of branched, 
relatively high-molecular-weight polyoxyalkylene-polyols and 
amine-initiated chain extenders having hydroxyl numbers in the range from 
450 to 500. The polyaddition reaction can be activated by means of 
organotin compounds (Kunststoff-Handbuch, Volume VII, Polyurethane, 2nd 
Edition, 1983, edited by D. G. Oertel, Carl Banset Verlag, Munich, 
Vienna). 
EP-A-0 490 145 describes composite elements comprising at least one outer 
layer of polyvinyl chloride or a polyvinyl chloride-containing polymer 
mixture and a PU foam, preferably a semirigid or rigid PU foam. 
PU foams are expediently produced with addition of tertiary amines as 
catalysts, since these accelerate both the reaction between the hydroxyl 
groups of the polyhydroxyl compounds and the NCO groups of the 
polyisocyanates, the urethane formation and the reaction between water and 
NCO groups with formation of amino groups and carbon dioxide as blowing 
gas, the blowing reaction; in particular in the one-shot process, the 
rates of the reactions occurring alongside one another must be matched 
precisely to one another. Since crosslinking reactions with formation of 
allophanate, urea, biuret and cyanurate structures can also take place 
alongside the polyaddition and blowing reactions during foam formation, 
the catalysts employed must ensure that these various reactions take place 
synchronously. The catalysts must neither lose their catalytic activity 
due to premature incorporation into the polyurethane structure nor 
accelerate hydrolyric decomposition of the resultant PU foam. 
A disadvantage of many of the tertiary amines used as catalysts in industry 
is their unpleasant odor, which is transferred to the PU foams produced 
and can adversely affect their use in certain applications. According to 
DE-A-23 21 884 (GB-A-1,344,038), PU foams are therefore produced using 
polyether-polyols prepared by means of a tertiary amine as catalyst in 
combination with an acid and a silicone oil. 
Also known are highly reactive polyoxyalkylene-polyols containing bonded 
tertiary amino groups; according to EP-A-0 539 819, these are prepared by 
oxyalkylation of an initiator molecule containing at least two reactive 
hydrogen atoms and at least one tertiary amino group bonded via a spacer 
bridge comprising at least three methylene groups, by means of at least 
one alkylene oxide. The highly reactive polyoxyalkylene-polyols, which 
preferably have a functionality of 2 or 3 and a molecular weight of from 
2800 to 6200 and are prepared using N,N-dimethyl-1,4-diaminobutane, 
N,N-dimethyl-1,3-diaminopropane and N,N-dimethyldipropylenetriamine as 
initiator molecules, are used for the production of compact or cellular, 
preferably flexible polyisocyanate polyaddition products. 
Polyoxyalkylene-polyols of this type have high catalytic activity in PU 
formulations for the production of flexible and semirigid PU foams. 
It is an object of the present invention to ensure that the various 
reactions during the production of PU foams, preferably semirigid, and 
rigid PU foams, occur synchronously while avoiding odor nuisance during 
the foaming process and due to the resultant foam. It is a further object 
to reduce the formation of voids in the foam and thus drastically to 
reduce the reject rate in the foam back of dashboards and other composite 
elements, for example those having top layers of polyvinyl chloride and 
other polyvinyl chloride-containing polymer mixtures. Through the 
improvement in the PU foam structure, the mechanical property level is to 
be increased and homogenized over the entire PU molding. A further aim is 
to improve the flow properties of the foamable reaction mixture and to 
extend the processing range with respect to foaming equipment and 
conditions, for example the temperature conditions. It should be possible 
to modify the mechanical properties of the PU foams by means of suitable 
additives which are compatible with PU formative components. The PU foams, 
preferably semirigid and rigid PU foams, should be very substantially 
fogging-free. 
We have found that, surprisingly, this object is achieved by using selected 
polyoxyalkylene-polyols initiated by means of aliphatic polyamines as all 
or some of the polyhydroxyl compound. 
The present invention accordingly provides a process for the production of 
PU foams, preferably semirigid or rigid PU foams, by reacting 
a) at least one organic or modified organic polyisocyanate or a mixture of 
an organic and a modified organic polyisocyante with 
b) at least one relatively high-molecular-weight polyhydroxyl compound 
containing at least two reactive hydrogen atoms, and 
c) if desired, low-molecular-weight chain extenders and/or crosslinking 
agents, 
in the presence of 
d) blowing agents and, if desired, 
e) catalysts and 
f) additives, 
wherein the polyhydroxyl compound (b) is a polyoxyalkylene-polyol (b1) 
having a hydroxyl number of from 30 to 500, obtainable by alkoxylation of 
at least one initiator molecule from the group consisting of 
N,N'-bis(3-aminopropyl)ethylenediamine, tripropylenetetramine and 
tetrapropylenepentamine, or a mixture of at least two of said initiator 
molecules, using at least one alkylene oxide. 
The present invention furthermore provides polyoxyalkylenepolyols having a 
hydroxyl number of from 30 to 500 obtainable by polyaddition of at least 
one alkylene oxide onto an initiator molecule from the group consisting of 
N,N'-bis(3-aminopropyl)ethylenediamine, tripropylenetetramine and 
tetrapropylenepentamine and technical-grade mixtures thereof. 
The polyoxyalkylene-polyols containing bonded tertiary amino groups which 
can be used in accordance with the invention are catalytically active and, 
in particular in combination with carboxylic acids, accelerate the 
polyaddition reaction of organic polyisocyanates with polyhydroxyl 
compounds. Their addition to PU reaction mixtures, even in extremely small 
amounts, can cause a significant shortening of the mold dwell time in the 
production of PU molded foams. This technical advantage, which also 
results in a reduction in production costs, is of considerable importance, 
in particular in the production of rigid PU foe moldings. The novel 
polyoxyalkylene-polyols are excellent solvents for certain blowing agents, 
for example (cyclo)alkanes, in particular cyclohexane, their addition 
enabling a considerable reduction in viscosity. In the case of rigid PU 
foams, their addition can reduce brittleness and, with the additional use 
of plasticizers for which they are solubilizers, allow the ridigity to be 
adjusted as desired, i.e. according to technical requirements. 
The PU foams, in particular semirigid PU foams, have excellent aging values 
and exhibit no exudation of volatile compounds. 
Reaction mixtures for the production of PU foams have very good flow 
properties and, in contrast to, for example, ethylenediamine-initiated 
polyoxyalkylene-polyols, do not have an adverse effect on the foaming 
times. In spite of a reduction in density, the mechanical properties of 
the odorless PU foams produced in accordance with the invention can be 
improved. 
The low tendency toward formation of voids in the PU foams is advantageous 
and therefore noteworthy. In the foam backing of, for example, dashboards 
and other composite elements, for example those having top layers of 
polyvinyl chloride (PVC) or other PVC-containing polymer mixtures, 
thermoplastic polyurethane or acrylonitrile-styrene-acrylate rubber (ASA), 
the reject rate can thus be drastically reduced. 
The following details apply to the novel process for the production of PU 
foams, preferably semirigid and rigid PU foams, and to the starting 
materials-which can be used for this purpose: 
a) Suitable isocyanates for the production of the PU foams, preferably 
semirigid and rigid PU foams, are the organic, for example aliphatic, 
cycloaliphatic and preferably aromatic, diisocyanates and/or 
polyisocyanates (a) known per se. Specific examples of aromatic 
polyisocyanates are: mixtures of 4,4'- and 2,4'-diphenylmethane 
diisocyanate (MDI), mixtures of MDI and polyphenyl-polymethylene 
polyisocyanates (crude MDI), expediently having a content of MDI isomers 
of at least 30% by weight, preferably from 40 to 90% by weight or more, 
based on the total weight of the mixture, 2,4- and 2,6-tolylene 
diisocyanate (TDI) and the corresponding commercially available isomer 
mixtures, mixtures of TDI and MDI and/or crude MDI. 
Other suitable organic polyisocyanates (a) are modified organic 
polyisocyanates, i.e. products obtained by chemical reaction of organic 
diisocyanates and/or polyisocyanates. Mention may be made by way of 
example of diisocyanates and/or polyisocyanates containing ester, urea, 
biuret, allophanate, isocyanurate and preferably carbodiimide, 
uretoneimine and/or urethane groups. Specific mention may be made of, for 
example: urethane group-containing prepolymers hating an NCO content of 
from 14 to 2.8% by weight, preferably from 12 to 3.5% by weight, or 
quasiprepolymers having an NCO content of from 35 to 14% by weight, 
preferably from 34 to 22% by weight, where urethane group-modified 
polyisocyanates made from TDI have, in particular, an NCO content of from 
34 to 28 % by weight and those made from 4,4'-MDI, 4,4'- and 2,4'-MDI 
isomer mixtures or crude MDI have, in particular, an NCO content of from 
28 to 22% by weight, based on the total weight, and are prepared by 
reacting diols, oxyalkylene glycols and/or polyoxyalkylene glycols having 
molecular weights of from 62 to 6000, preferably from 134 to 4200, with 
TDI, 4,4'-MDI, MDI isomer mixtures and/or crude MDI, for example at 
temperatures of from 20.degree. to 110.degree. C., preferably from 
50.degree. to 90.degree. C., where, as oxyalkylene and polyoxyalkylene 
glycols, which may be employed individually or as mixtures, mention may be 
made by way of example of: diethylene glycol, dipropylene glycol, 
polyoxyethylene glycol, polyoxypropylene glycol and 
polyoxypropylene-polyoxyethylene glycol, and polyisocyanates containing 
carbodiimide groups and/or isocyanurate groups, for example based on MDI 
isomers and/or TDI. 
However, particular success has been achieved by, and preference is 
therefore given to, mixtures of 4,4'- and 2,4'-MDI, crude MDI having an 
MDI content of at least 30% by weight, based on the total weight, mixtures 
of 4,4'- and 2,4'-MDI and mixtures of 2,4- and 2,6-TDI, mixtures of crude 
MDI and mixtures of 2,4- and 2,6-TDI, urethane group-containing 
polyisocyanate mixtures having an NCO content of from 28 to 14% by weight, 
based on the total weight, based on MDI and/or crude MDI. 
The organic polyisocyanates which can be used according to the invention 
can be prepared by known processes, for example by reaction of the 
corresponding polyamines with phosgene to give carbamoyl chloride 
intermediates, followed by thermolysis thereof to give polyisocyanates, or 
by phosgene-free methods, for example by reaction of the corresponding 
polyamines with urea and/or carbamates and alcohols to give monomeric 
polyurethanes, followed by thermolysis thereof to give polyisocyanates and 
alcohols. 
b) The relatively high-molecular-weight polyhydroxyl compounds (b) used 
according to the invention are polyoxyalkylene-polyols (b1) having a 
hydroxyl number of from 30 to 500, preferably from 200 to 450, in 
particular from 250 to 410, which are obtainable by alkoxylation of at 
least one initiator molecule from the group consisting of 
N,N'-bis(3-aminopropyl)ethylenediamine, tripropylenetetramine and 
tetrapropylenepentamine, or a mixture of at least two of the said 
initiator molecules. 
Said initiator molecules can be used in the form of chemically pure 
compounds having a functionality of from 6 to 8, as industrially 
obtainable compounds or in the form of an industrially obtainable mixture 
contaminated by other polyamines. The tripropylenetetramine employed is 
preferably industrially obtainable tripropylenetetramine mixtures 
containing polyamines of the formulae 
##STR1## 
and 
EQU CH.sub.3 CH.sub.2 CH.sub.2 --NH--CH.sub.2 CH.sub.2 CH.sub.2 --NH--CH.sub.2 
CH.sub.2 CH.sub.2 --NH--CH.sub.2 CH.sub.2 CH.sub.3 
and the tetrapropylenepentamines employed are preferably industrially 
obtainable tetrapropylenepentamine mixtures containing 
##STR2## 
and 
EQU H.sub.2 N--(CH.sub.2).sub.3 .dagger.NH--(CH.sub.2).sub.3 .brket 
close-st.NH--(CH.sub.2).sub.3 --NH.sub.2. 
The polyoxyalkylene-polyols (b1) which can be used in accordance with the 
invention can be prepared by known processes, for example by anionic 
polymerization of one or more alkylene oxides having 2 to 4 carbon atoms 
in the presence of at least one of said initiator molecules, in absence or 
preferably presence of a catalyst, for example an alkali metal hydroxide, 
such as sodium hydroxide or potassium hydroxide, or an alkali metal 
alkoxide, such as sodium methoxide, sodium ethoxide, potassium ethoxide or 
potassium isopropoxide. In a specific preparation variant, the alkoxlation 
can first be carried out in the absence of catalysts, and the basic 
catalysts can be introduced into the reaction mixture with increasing 
molecular weight of the novel polyoxyalkylene-polyols formed. Examples of 
suitable alkylene oxides are 1,2- and 2,3-butylene oxide, styrene oxide 
and preferably ethylene oxide and/or 1,2-propylene oxide. The alkylene 
oxides can be used here individually, or alternately one after the other 
or as a mixture. 
For the production of the PU foams, preferably semirigid and rigid PU 
foams, the novel polyoxyalkylene-polyols (b1) can be used as the only 
relatively high-molecular-weight polyhydroxyl compound (b). However, in 
order to modify the mechanical properties of the PU foams or for technical 
reasons associated with processing, it may be expedient to use, as 
polyhydroxyl compounds (b), mixtures containing at least one novel 
polyoxyalkylene-polyol (b1) and at least one additional polyhydroxyl 
compound (b2) having a functionality of from 2 to 8, in particular from 2 
to 3, for semirigid PU foams and from 3 to 6 for rigid PU foams, and 
having a hydroxyl number of from 15 to 500, preferably from 24 to 280, for 
semirigid PU foams and from 280 to 500 or more for rigid PU foams, with 
the exception of polyoxyalkylene-polyols as defined in (b1). 
The mixtures of (b1) and (b2) preferred as polyhydroxyl compounds (b) have 
a hydroxyl number of from 30 to 500 and expediently contain, based on the 
total weight of (b1) and (b2), from 0.1 to 50% by weight, preferably from 
0.5 to 30% by weight, in particular from 1 to 10% by weight, of (b1), and 
from 99.9 to 50% by weight, preferably from 99.5 to 70% by weight, in 
particular from 99 to 90% by weight, of (b2). 
Relatively high-molecular-weight polyhydroxyl compounds (b2) which have 
proven successful are, for example, polyoxyalkylene-polyols other than 
(b1), polyester-polyols, advantageously those prepared from 
alkanedicarboxylic acids and polyhydric alcohols, polythioether-polyols, 
polyester-amides, hydroxyl-containing polyacetals, hydroxyl-containing, 
preferably aliphatic, polycarbonates or mixtures of at least two of said 
polyhydroxyl compounds. Preference is given to polyester-polyols and/or, 
in particular, polyoxyalkylene-polyols whose properties do not come under 
the definition of (b1). 
Such polyoxyalkylene-polyols (b2) can be prepared by known processes, for 
example from one or more alkylene oxides having 2 to 4 carbon atoms in the 
alkylene radical by anionic polymerization using alkali metal hydroxides 
or alkoxides as catalysts and with addition of at least one initiator 
molecule containing from 2 to 8 reactive bonded hydrogen atoms, or by 
cationic polymerization using Lewis acids, such as antimony pentachloride, 
boron fluoride etherate inter alia, or bleaching earth as catalysts. 
Examples of suitable alkylene oxides for this purpose are tetrahydrofuran, 
1,3-propylene oxide, 1,2- and 2,3-butylene oxide, styrene oxide and 
preferably ethylene oxide and 1,2-propylene oxide. The alkaline oxides can 
be used individually, alternately one after the other or as mixtures. 
Examples of suitable initiator molecules are: water, organic dicarboxylic 
acids, such as succinic acid, adipic acid, phthalic acid and terephthalic 
acid, and preferably polyhydric, in particular dihydric to octahydric 
alcohols or dialkylene glycols, for example ethanediol, 1,2- and 
1,3-propanediol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 
1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitol 
and sucrose. 
The polyoxyalkylene-polyols, preferably polyoxypropylene- and 
polyoxypropylene-polyoxyethylene-polyols, expediently have, for the 
production of semirigid PU foams, a functionality of, preferably, from 2 
to 4, in particular from 2 to 3, and hydroxyl numbers of, preferably from 
24 to 160, and suitable polyoxytetramethylene glycols usually have a 
hydroxyl number of from 37 to 160. 
Polyhydroxyl compounds (b2) which have proven highly successful are, for 
example, polyoxyalkylene-polyols (b2) or mixtures thereof having a 
functionality of from 2 to 4, preferably 2 to 3, and a hydroxyl number of 
from 15 to 300, preferably from 15 to 280, in particular from 18 to 260, 
prepared by polyaddition of ethylene oxide, 1,2-propylene oxide or 
mixtures of ethylene oxide and 1,2-propylene oxide onto at least one 
initiator molecule of the formula 
##STR3## 
where R.sup.1 and R.sup.2 are identical or different and are linear or 
branched C.sub.1 - to C.sub.4 -alkyl, the two radicals together are 
C.sub.4 - to C.sub.6 -cycloalkylene, in which one methylene group may be 
replaced by an --O-- or --NR.sup.5 -- bridge, where R.sup.5 is C.sub.1 - 
to C.sub.4 -alkyl, or are identical or different and are dialkylaminoalkyl 
of the formula 
##STR4## 
where R.sup.6 and R.sup.7 are identical or different and are linear or 
branched C.sub.1 -to C.sub.4 -alkyl, or the two radicals together are 
C.sub.4 - to C.sub.6 -cycloalkylene, in which one methylene group may be 
replaced by an --O-- or --NR.sup.5 -- bridge, and X is an integer having a 
value of at least 3, 
z is an integer having a value of at least 3, 
R.sup.3 is a C.sub.2 - to C.sub.4 -alkylene, 
y is zero or a number from 1 to 3, and 
R.sup.4 is hydrogen or C.sub.1 - to C.sub.4 -alkyl, with the proviso that y 
is zero if R.sup.4 is hydrogen. 
Preferred polyoxyalkylene-polyols (b2) having a functionality of from 2 to 
3 and a hydroxyl number of from 15 to 300, in particular from 18 to 260, 
can be prepared, for example, by polyaddition of at least one alkylene 
oxide, preferably ethylene oxide, 1,2-propylene oxide or a mixture of 
ethylene oxide and 1,2-propylene oxide, onto an initiator molecule from 
the group consisting of N,N-dimethyl-1,3-diaminopropane, 
N,N-dimethyl-1,4-diaminobutane and in particular 
N,N-dimethyldipropylenetriamine. Highly reactive polyoxyalkylenepolyols 
(b2) of this type, in which the tertiary amino group is bonded to the 
--NH-- and/or --NH.sub.2 groups which react with alkylene oxide via a 
spacer bridge comprising at least 3 methylene radicals, are described in 
DE-A-41 35 588, the entire disclosure content of which is incorporated 
herein by way of reference. 
Other preferred polyhydroxyl compounds (b2) are block 
polyoxypropylene-polyoxyethylene-polyols (b2) or mixtures thereof having a 
hydroxyl number of from 15 to 65, preferably from 24 to 40, and a content 
of terminal ethylene oxide units of from 2 to 9% by weight, preferably 
from 3 to 8% by weight, in particular from 5 to 7% by weight, based on the 
weight of the polyoxypropylene units, which are prepared by anionic 
polymerization of 1,2-propylene oxide onto an initiator molecule mixture 
having a mean functionality of from 2.3 to 2.8, preferably from 2.3 to 
2.7, in particular from 2.5 to 2.7, at elevated temperature, which 
comprises water and glycerol and/or trimethylolpropane, and polymerization 
of ethylene oxide onto the resultant polyoxypropylene adduct. Block 
polyoxypropylene-polyoxyethylene-polyols (b2) of said type have been 
disclosed in EP-A-433 878 and EP-A-433 889, the entire descriptions of 
which are incorporated herein by way of reference. 
Other suitable polyhydroxyl compounds (b2) are polymer-modified 
polyoxyalkylene-polyols (b2), preferably graft polyoxyalkylene-polyols, in 
particular those based on styrene and/or acrylonitrile, which are prepared 
by in-situ polymerization of acrylonitrile, styrene or preferably mixtures 
of styrene and acrylonitrile, for example in a weight ratio of from 90:10 
to 10:90, preferably from 70:30 to 30:70, expediently in the 
abovementioned polyoxyalkylene-polyols, as described in German Patents 11 
11 934, 12 22 669 (U.S. Pat. Nos. 3,304,273, 3,383,351, 3,523,093), 11 52 
536 (GB 1,040,452) and 11 52 537 (GB 987,618), and polyoxyalkylene-polyol 
dispersions containing, as dispersant phase, usually in an amount of from 
1 to 50% by weight, preferably from 2 to 25% by weight: for example 
polyureas, polyhydrazides, melamine and/or polyurethanes containing bonded 
tertiary amino groups, which are described, for example, in EP-B-011 752 
(U.S. Pat. No. 4,304,708), U.S. Pat. No. 4,374,209 and DE-A-32 31 497. 
The polyoxyalkylene-polyols (b2) can be used individually or in the form of 
mixtures. 
Other polyhydroxyl compounds (b2) which can be used are polyester-polyols, 
which can be prepared, for example, from alkanedicarboxylic acids having 2 
to 12 carbon atoms, preferably alkanedicarboxylic acids having 4 to 6 
carbon atoms, or mixtures of alkanedicarboxylic acids and/or aromatic 
polycarboxylic acids and polyhydric alcohols, preferably diols, having 2 
to 12 carbon atoms, preferably 2 to 6 carbon atoms, and/or alkylene 
glycols. Examples of suitable alkanedicarboxylic acids are: succinic acid, 
glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid and 
decanedicarboxylic acid. 
Examples of suitable aromatic polycarboxylic acids are phthalic acid, 
isophthalic acid and terephthalic acid. The alkanedicarboxylic acids can 
be used individually or as a mixture with one another. Instead of the free 
dicarbxocylic acids, it is also possible to use the corresponding 
dicarboxylic acid derivatives, for example dicarboxylic acid monoesters or 
diesters with alcohols having i to 4 carbon atoms or dicarboxylic 
anhydrides. Preference is given to dicarboxylic acid mixtures comprising 
succinic acid, glutaric acid and adipic acid, in mixing ratios of, for 
example, from 20 to 35:35 to 50:20 to 32 parts by weight, in particular 
adipic acid. Examples of dihydric and polyhydric alcohols, in particular 
diols or alkylene glycols, are: ethanediol, diethylene glycol, 1,2- and 
1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 
1,6-hexanediol, 1,10-decanediol, glycerol and trimethylolpropane. 
Preference is given to ethanediol, diethylene glycol, 1,4-butanediol, 
1,5-pentanediol, 1,6-hexanediol and mixtures of at least two of the said 
diols,in particular mixtures of 1,4-butanediol, 1,5-pentanediol and 
1,6-hexanediol. It is also possible to employ polyester-polyols made from 
lactones, for example .epsilon.-caprolactone, or hydroxycarboxylic acids, 
for example .omega.-hydroxycaproic acid. 
In order to prepare the polyester-polyols, the mixtures of aromatic and 
aliphatic dicarboxylic acids and preferably alkanedicarboxylic acids 
and/or derivatives thereof and polyhydric alcohols can be polycondensed in 
the absence or preferably in the presence of esterification catalysts, 
expediently in an atmosphere of inert gases, for example nitrogen, helium, 
argon inter alia, in the melt at temperatures of from 150.degree. to 
250.degree. C., preferably from 180.degree. to 220.degree. C., if desired 
under reduced pressure, to the desired acid number, which is 
advantageously less than 10, but preferably less than 2. In a preferred 
embodiment, the esterification mixture is polycondensed at the 
abovementioned temperatures to an acid number of from 80 to 30, preferably 
from 40 to 30, under atmospheric pressure and subsequently under a 
pressure of less than 500 mbar, preferably from 50 to 150 mbar. Examples 
of suitable esterification catalysts are iron, cadmium, cobalt, lead, 
zinc, antimony, magnesium, titanium and tin catalysts in the form of 
metals, metal oxides metal salts. However, the polycondensation can also 
be carried out in the liquid phase in the presence of diluents and/or 
entrainers, for example benzene, toluene, xylene or chlorobenzene, for 
azeotropic removal of the water of condensation by distillation. 
In order to prepare the polyester-polyols, the organic polycarboxylic acids 
and/or derivatives thereof and polyhydric alcohols are advantageously 
polycondensed in a molar ratio of from 1:1 to 1.8, preferably from 1:1.05 
to 1.2. 
The resultant polyester-polyols preferably have a functionality of from 2 
to 4, in particular from 2 to 3, and a hydroxyl number of from 24 to 200, 
preferably from 32 to 140, in particular from 40 to 94. 
Examples of suitable hydroxyl-containing polyacetals are the compounds 
which can be prepared from glycols, such as diethylene glycol, triethylene 
glycol, 4,4'-dihydroxyethoxydiphenyldimethylmethane, hexanediol and 
formaldehyde. Suitable polyacetals can also be prepared by polymerization 
of the cyclic acetals. 
Examples of suitable hydroxyl-containing polycarbonates are those of the 
type known per se, which can be prepared, for example, by reacting diols, 
such as 1,3-propanediol, 1,4-butanediol and/or 1,6-hexanediol, diethylene 
glycol, triethylene glycol or tetraethylene glycol, with diaryl 
carbonates, for example diphenyl carbonates, or phosgene. 
The polyester-amides include, for example, the predominantly linear 
condensates obtained from polybasic, saturated and/or unsaturated 
carboxylic acids or anhydrides thereof, and polyhydric, saturated and/or 
unsaturated aminoalcohols, or mixtures of polyhydric alcohols and 
aminoalcohols and/or polyamines. 
c) The production of the PU foams by the novel process can also be carried 
out in the presence of low-molecular-weight, difunctional chain extenders, 
low-molecular-weight, trifunctional or polyfunctional, preferably 
trifunctional or tetrafunctional, crosslinking agents or mixtures of chain 
extenders and crosslinking agents, in addition to the relatively 
high-molecular-weight polyhydroxyl compounds (b). 
Examples of suitable chain extenders and crosslinking agents (c) of this 
type are diols, such as (cyclo)alkanediols and dialkylene glycols, and/or 
polyhydric alcohols, preferably triols and tetraols, having molecular 
weights of less than 400, preferably from 60 to 300. Examples of suitable 
compounds are aliphatic, cycloaliphatic and/or araliphatic diols having 2 
to 14 carbon atoms, preferably 4 to 10 carbon atoms, for example ethylene 
glycol, 1,3-propanediol, 1,10-decanediol, o-, m- and 
p-dihydroxycyclohexane, diethylene glycol, dipropylene glycol and 
preferably 1,4-butanediol, 1,6-hexanediol and 
bis(2-hydroxyethyl)hydroquinone, and triols, such as 1,2,4- and 
1,3,5-trihydroxycyclohexane, glycerol and trimethylolpropane. Other 
suitable chain extenders and crosslinking. linking agents are 
low-molecular-weight, hydroxyl-containing polyalkylene oxides having 
molecular weights of up to 400 based on ethylene oxide and/or 
1,2-propylene oxide and, as initiator molecules, the diols and/or triols 
mentioned by way of example. 
If mixtures of relatively high-molecular-weight polyhydroxyl compounds (b) 
and chain extenders and/or crosslinking agents (c) are used, for example 
to modify the mechanical properties, for example the hardness, these 
expediently contain the chain extenders and/or crosslinking agents (c) in 
an amount of from 0.5 to 20% by weight, preferably from 10 to 15% by 
weight, based on the total weight, the alkali ion content of the mixture 
usually being less than 10 ppm, preferably less than 5 ppm, in particular 
less than 3 ppm. 
Other suitable crosslinking agents (c) are those having a high content of 
alkali metal ions, preferably potassium ions, for example of from 150 to 
1200 ppm, preferably from 150 to 800 ppm, in particular from 400 to 600 
ppm. 
d) The blowing agents (d) which can be used for the production of the PU 
foams, preferably semirigid and rigid PU foams, preferably include water, 
which reacts with isocyanate groups with formation of carbon dioxide. The 
amounts of water expediently employed are from 0.1 to 8 parts by weight, 
preferably from 1.5 to 5.0 parts by weight, in particular from 2.5 to 3.5 
parts by weight, based on 100 parts by weight of the polyhydroxyl 
compounds (b) or the mixtures of relatively high-molecular-weight 
polyhydroxyl compounds (b) and chain extenders and/or crosslinking agents. 
It is also possible to employ physical blowing agents, as a mixture with 
water or as the only blowing agent. Suitable compounds are liquids which 
are inert toward the organic, modified or unmodified polyisocyanate (a) 
and have boiling points of below 100.degree. C., preferably below 
50.degree. C., in particular from -50.degree. to 40.degree. C., at 
atmospheric pressure, so that they evaporate under the effect of the 
exothermic polyaddition reaction. Examples of such preferred liquids are 
hydrocarbons, for example n- and isopentane, preferably technical-grade 
mixtures of n- and isopentane, n- and isobutane, n- and isopropane, 
cycloalkanes, for example cyclohexane and cyclopentane, ethers, for 
example furan, dimethyl ether and diethyl ether, ketones, for example 
acetone and methyl ethyl ketone, alkyl carbonates, for example methyl 
formate, dimethyl oxalate and ethyl acetate, and halogenated hydrocarbons, 
for example methylene chloride, dichloromonofluoromethane, 
difluoromethane, difluorochloromethane, trifluoromethane, trifluoroethane, 
tetrafluoroethane, heptafluoropropane, 1-chloro-2,2-difluoroethane (142), 
1-chloro-1,1-difluoroethane (142b) and 1-chloro-1,2-difluoroethane (142a). 
It is also possible to use mixtures of these low-boiling liquids with one 
another, for example mixtures of difluorochloromethane and 142b, and/or 
with other substituted or unsubstituted hydrocarbons. 
The requisite amount, or the requisite amount in addition to water, of 
physical blowing agents can be determined in a simple manner as a function 
of the desired foam density and is from about 0 to 25 parts by weight, 
preferably from i to 25 parts by weight, in particular from 2 to 15 parts 
by weight, per 100 parts by weight of the polyhydroxyl compounds (b). It 
may be expedient to mix the modified or unmodified polyisocyanates (a) 
with the inert, physical blowing agents and thus to reduce the viscosity. 
e) The PU foams can be produced by the novel process in the absence of 
conventional amine catalysts. However, the reaction is expediently carried 
out in the presence of conventional catalysts (e), which greatly 
accelerate the reaction of the organic and/or modified organic 
polyisocyanates (a) with the polyhydroxyl compounds (b) and chain 
extenders and/or crosslinking agents (c). Examples of suitable catalysts 
are alkali metal salts of monocarboxylic acids containing linear or 
branched alkyl radicals having 1 to 20 carbon atoms, preferably 1 to 18 
carbon atoms, and/or dicarboxylic acids containing linear or branched 
alkyl radicals having 2 to 20 carbon atoms, preferably 2 to 12 carbon 
atoms, for example potassium formate, potassium acetate, potassium 
octanoate, potassium maleate and dipotassium adipate, and organometallic 
compounds, preferably organotin compounds, for example tin(II) salts of 
organic carboxylic acids, for example tin(II) diacerate, tin(II) 
dioctanoate, tin(II) diethylhexanoate and tin(II) dilaurate, and the 
dialkyltin(IV) salts of organic carboxylic acids, for example dibutyltin 
diacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltin 
diacetate. Such catalysts are described, for example, in DE-A-3 048 529. 
Dialkyltin(IV) mercapto compounds, for example bislauryltin(IV) 
dimercaptide, have also proven highly suitable. 
The catalysts are usually used in an amount of from 0.001 to 0.2 part by 
weight, preferably from 0.005 to 0.015 part by weight, per 100 parts by 
weight of the formative components (a) to (c). 
f) If desired, additives (e) can also be incorporated into the reaction 
mixture for the production of the PU foams, preferably semirigid and rigid 
PU foams. Examples which may be mentioned are acids, plasticizers, 
surfactants, foam stabilizers, cell regulators, fillers, antioxidants, 
dyes, pigments, flameproofing agents, antihydrolysis agents and 
fungistatic and bacteriostatic substances. 
For the production of the PU foams by the novel process, inorganic acids, 
organic acids or mixtures of inorganic and organic acids can be used as 
preferred additive (f). Examples of inorganic acids which have proven 
successful are polyphosphoric acids, monobasic and polybasic phosphoric 
acids, preferably triphosphoric acid, and hydrochloric acid. Preference is 
given to organic acids, in particular those from the group consisting of 
monocarboxylic acids, polycarboxylic acids, preferably dicarboxylic acids, 
and aromatic sulfonic acids. Organic acids which may be mentioned by way 
of example are mono- and dicarboxylic acids, for example formic acid, 
acetic acid, propionic acid and preferably ricinoleic acid, hydroxystearic 
acids, oxalic acids, succinic acid, maleic acid, fumaric acid, tartaric 
acid, citric acid, adipic acid, benzoic acid, phthalic acid, terephthalic 
acid and isophthalic acid, and sulfonic acids, for example benzenesulfonic 
acid and p-toluenesulfonic acid. Depending on their pKa value and 
molecular weight and on the basicity of the polyhydroxyl compounds (b), 
the inorganic and/or organic acids are usually used in an amount of from 
0.1 to 20 parts by weight, based on 100 parts by weight of polyhydroxyl 
compound (b), it being possible to determine the precise amounts by weight 
by simple preliminary experiments. 
Organic acids which have proven particularly successful are long-chain 
fatty acids, for example ricinoleic acid and hydroxyfatty acids, for 
example hydroxystearic acids, which can be obtained from natural oils, and 
can be converted into hydroxyfatty acids by epoxidation of the unsaturated 
double bonds and adduction of monohydric and/or polyhydric alcohols onto 
the epoxide group. Hydroxyl-containing organic acids of this type have 
proven particularly successful in combination with crosslinking agents (c) 
having a high content of alkali metal ions, since this combination has an 
excellent emuslification action and gives the PU foams an extremely 
homogeneous foam structure. When a crosslinking agent (c) having an alkali 
metal ion content of less than 10 ppm is used in combination with the 
organic acids, the cream time of the reaction mixture is extended. 
Other additives (f) which have proven successful are plasticizers, which, 
inter alia, improve the flow behavior of the reaction mixture. Suitable 
examples are plasticizers from the group consisting of dialkyl phthalates, 
for example those having 4 to 20 carbon atoms, preferably 9 to 11 carbon 
atoms, in the alkyl radical. These plasticizers are commercially available 
under the trade name Palatinol.RTM. from BASF Aktiengesellschaft. Other 
suitable plasticizers are phosphates, for example tricresyl phosphate, 
phenyl dicresyl phosphate, inter alia, which simultaneously improve the 
flame resistance of the PU foams. 
Examples of suitable surfactants are compounds which serve to support 
homogenization of the starting materials and may also be suitable for 
regulating the cell structure. Examples which may be mentioned are 
emulsifiers, such as sodium salts of castor oil sulfates or of fatty 
acids, and salts of fatty acids with amines, for example diethylamine 
oleate, diethanolanane stearate, diethanolamine ricinoleate, salts of 
sulfonic acids, for example alkali metal or ammonium salts of 
dodecylbenzene- or dinaphthylmethanedisulfonic acid and ricinoleic acid; 
foam stabilizers, such as siloxane-oxyalkylene copolymers and other 
organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty 
alcohols, paraffin oils, esters of castor oil and ricinoleic acid, turkey 
red oil and groundnut oil, and cell regulators, such as paraffins, fatty 
alcohols and dimethylpolysiloxanes. Furthermore, the emulsification action 
and cell structure can be improved and/or the foam can be stabilized using 
oligomeric polyacrylates containing polyoxyalkylene and fluoroalkane 
radicals as side groups. The surfactants are usually used in amounts of 
from 0.01 to 5 parts by weight, based on 100 parts by weight of 
polyhydroxyl compounds (b) and chain extenders and/or crosslinking agents 
(c). 
For the purposes of the present invention, the term fillers, in particular 
reinforcing fillers, is taken to mean conventional organic and inorganic 
fillers and reinforcing materials known per se. Specific examples which 
may be mentioned are: inorganic fillers, such as silicate minerals, for 
example phyllosilicates, such as antigorite, serpentine, hornblende, 
amphibole, chrisotile, zeolites and talc; metal oxides, such as kaolin, 
aluminum oxides, aluminum silicate, titanium oxide and iron oxides, metal 
salts, such as chalk, barytes and inorganic pigments, such as cadmium 
sulfide and zinc sulfide, and glass particles. Examples of suitable 
organic fillers are: carbon black, melamine, collopbony, cyclopentadienyl 
resins and graft polymers. 
The inorganic and organic fillers can be used individually or as mixtures 
and are advantageously incorporated into the reaction mixture in amounts 
of from 0.5 to 50% by weight, preferably from 1 to 40% by weight, based on 
the weight of the components (a) to (c). 
Examples of suitable flameproofing agents are tricresyl phosphate, 
tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate, 
tris(1,3-dichloropropyl) phosphate, tris(2,3-dibromopropyl) phosphate and 
tetrakis(2-chloroethyl)ethylene diphosphate. 
In addition to the abovementioned halogen-substituted phosphates, it is 
also possible to use inorganic flameproofing agents, such as red 
phosphorus, aluminum oxide hydrate, antimony trioxide, ammonium sulfate, 
ammonium polyphosphate and calcium sulfate, expandable graphite, urea or 
cyanuric acid derivatives, for example melamine or melamine cyanurate, or 
mixtures of at least two flameproofing agents, for example ammonium 
polyphosphates and melamine and, if desired, expandable graphite and/or 
starch for flameproofing the PU foams produced according to the invention. 
In general, it has proven expedient to use from 5 to 50 parts by weight, 
preferably from 5 to 25 parts by weight, of said flameproofing agents or 
mixtures per 100 parts by weight of components (a) to (c). 
Examples of antioxidants which can be used are non-volatile cryptophenols, 
for example the commercial products Irganox.RTM. 245 and Irganox.RTM. 1135 
from Ciba/Geigy, or sterically hindered amines, for example the commercial 
product Naugard.RTM. 445 from Uniroyal. 
Further details on the other conventional auxiliaries mentioned above are 
given in the specialist literature, for example the monograph by J. H. 
Saunders and K. C. Frisch, High Polymers, Volume XVI, Polyurethanes, parts 
1 and 2, Inter-science Publishers, 1962 and 1964 respectively, or the 
Kunst-stoff-Handbuch, Polyurethane, Volume VII, Carl-Hanser-Verlag, 
Munich, Vienna, 1st and 2nd Editions, 1966 and 1983 respectively. 
In order to produce the PU foams, preferably semirigid and rigid PU foams, 
the organic, modified or unmodified polyisocyanates (a), the polyhydroxyl 
compounds (b) and, if used, chain extenders and/or crosslinking agents (c) 
are reacted in the presence of the blowing agents (d) and, if used, 
catalysts (e) and additives (f), usually at from 0.degree. to 120.degree. 
C., preferably at from 15.degree. to 100.degree. C., in particular at from 
18.degree. to 80.degree. C., expediently in such amounts that 
advantageously from 0.5 to 2, preferably from 0.8 to 1.3, in particular 
approximately one, hydroxyl group(s) is bonded to (b) or (b) and (c) per 
NCO group. If water is used as one of the blowing agents or as the only 
blowing agent, it has proven expedient to use a ratio of, advantageously, 
from 0.5 to 5:1, preferably from 0.7 to 0.95:1, in particular from 0.75 to 
0.85:1, equivalents of water to equivalents of NCO groups. For the 
production of PU foams containing isocyanurate groups, an NCO:OH group 
ratio of from 2 to 25:1, preferably from 2 to 10:1, in particular from 2 
to 5:1, for example, has proven successful. 
The PU foams, preferably the semirigid and rigid PU foams, are expediently 
produced by the one-shot process by mixing two components A and B, where 
formative components (b) and (d) and, if used, (c), (e) and (f), are 
usually combined to form component A, and the organic and/or modified 
organic polyisocyanates (a), if desired mixed with inert, physical blowing 
agents, are used as component B. Components A and B need only be mixed 
vigorously before production of the PU foams. The reaction mixture can be 
foamed and allowed to cure in open or closed molds. Furthermore, 
prefabricated covering materials can be foam-backed to give moldings. 
The novel process is also particularly suitable for the production of PU 
molded foams. In this case, the reaction mixture, at from 15.degree. to 
80.degree. C., preferably from 30.degree. to 65.degree. C., is introduced 
into an expediently metallic, thermostatable mold temperature is usually 
from 20.degree. to 90.degree. C., preferably from 35.degree. to 70.degree. 
C. The reaction mixture is usually allowed to cure without pressure or 
with compaction, for example at degrees of compaction of from 1.1 to 8, 
preferably from 2 to 6, in particular from 2.2 to 4, in the closed mold. 
The PU foams produced by the novel process usually have densities of from 
0.025 to 0.25 g/cm.sup.3, preferably from 0.035 to 0.08 g/cm.sup.3, it 
also being possible for molded foams, for example those having a cellular 
core and a compacted peripheral zone, to have densities of from 0.08 to 
0.75 g/cm.sup.3, preferably from 0.2 to 0.6 g/cm.sup.3, depending on the 
degree of compaction used. The PU foams produced by the novel process are, 
as stated above, essentially odorless, have a uniform, essentially 
void-free cell structure and have a uniformly high mechanical property 
level. 
The reaction mixtures for the production of the PU foams are used, for 
example, in the vehicle industry, for example in the automotive, aircraft 
and shipbuilding industries, and in the refrigeration and construction 
industries for foam-filling and foam-backing of cavities, for example 
dashboards and control panels, as interlayers for sandwich elements or for 
foam-filling refrigerator and freezer casings. The PU foams are suitable 
as insulation materials, for example as lagging for piping or heating 
systems. They are also used as wall linings, housing parts, cushioning 
materials, armrests, headrests, sun visors, parcel shelves, glove boxes, 
safety covers and central consoles.

EXAMPLES 
Example 1 
Component A: a mixture comprising 
33.85 parts by weight of a block polyoxypropylene-polyoxyethylene-polyol 
having a hydroxyl number of 30 and a content of terminal ethylene oxide 
units of 5.9% by weight, based on the weight of the propylene oxide units, 
obtained by alkoxylation of an initiator molecule mixture comprising 
glycerol and water in a weight ratio of 1:0.98, 
0.25 part by weight of a glycerol-initiated polyoxyethylene (62.5% by 
weight)-polyoxypropylene (27.5% by weight)-polyoxyethylene (10% by 
weight)-polyol having a hydroxyl number of 42, 
35.00 parts by weight of a 1,2-propylene glycol-initiated polyoxypropylene 
(81.5% by weight)-polyoxyethylene (18.5% by weight) glycol having a 
hydroxyl number of 29, 
6.00 parts by weight of an N,N,-bis(3-aminopropyl)ethylenediamine-initiated 
polyoxypropylene-polyol having a hydroxyl number of 393, 
1.6 parts by weight of ricinoleic acid, 20.0 parts by weight of a 
di(C.sub.9 - to C.sub.11 -alkyl)phthalate, 2.2 parts by weight of water, 
0.45 part by weight of a 40% strength by weight potassium acetate solution 
in ethylene glycol, 
0.40 part by weight of black paste and 
1.0 part by weight of a sterically hindered amine as antioxidant 
(Naugard.RTM. 445). 
Component B: A mixture of diphenylmethane diisocyanate isomers and 
polyphenyl-polymethylene polyisocyanates having an NCO content of 31.3% by 
weight and a diphenylmethane diisocyanate isomer content of 39% by weight, 
based on the total weight. 
Foam backing of a dashboard for a motor vehicle: 
This is carried out using a Hennecke foaming apparatus fitted with an MQ 
mixing head with throttle setting 5, nozzles having a diameter of 1.3 mm 
for component A and of 0.8 mm for component B, and an output capacity of 
223 g/sec. The shot time was 4.2 to 5.05 seconds, corresponding to an 
output of 920 to 1126 g. 
For foam-backing of the dashboards, the PVC/ABS cover film was placed in a 
metallic mold thermostated at from 40.degree. to 43.degree. C., the mold 
was closed, components A and B were mixed in a weight ratio of 100:43 at 
30.degree. C. at 200 bar, and the reaction mixture was injected into the 
closed mold, where it was allowed to expand. 
The resultant dashboard was demolded after 3.5 minutes and then stored at 
80.degree. C. for 1 hour. There was no evidence of any sink marks. After 
24 hours, the molding exhibited excellent adhesion between the semirigid 
PU foam and the PVC/ABS film. 
30 avoid-free dashboards were produced without problems by the procedure 
described. The series experiment was then terminated. 
The reaction mixture had a setting time of 70 seconds and a rise time of 
105 seconds. The PU foam had a free-foamed density of 76 g/l. 
Example 2 
Component A: a mixture comprising 
47.50 parts by weight of a block polyoxypropylene-polyoxyethylene-polyol 
having a hydroxyl number of 30 and a content of terminal ethylene oxide 
units of 5.9% by weight, based on the weight of the propylene oxide units, 
obtained by alkoxylation of an initiator molecule mixture comprising 
glycerol and water in a weight ratio of 1:0.98, 
1.50 parts by weight of a glycerol-initiated polyoxyethylene (62.5% by 
weight)-polyoxypropylene (27.5% by weight)-polyoxyethylene (10% by 
weight)-polyol having a hydroxyl number of 42, 
42.3 parts by weight of a glycerol-initiated polyoxypropylene (86% by 
weight)-polyoxyethylene (14% by weight)-polyol having a hydroxyl number of 
28, 
1.00 parts by weight of a polyoxypropylene-polyol having a hydroxyl number 
of 394 initiated by means of technical grade tripropylenetetramine, 
5.00 parts by weight of an N,N-dimethyl-1,3-diaminopropane-initiated 
polyoxypropylene-polyol having a hydroxyl number of 250, 
0.5 part by weight of ricinoleic acid, 
2.2 parts by weight of water and 
1.0 part by weight of a sterically hindered amine as antioxidant 
(Naugard.RTM. 445). 
Component B: as in Example 1. 
The molding was produced by a method similar to that of Example 1, but 
components A and B were mixed in a weight ratio of 100:41.66. 
The molding, demolded after 3 minutes, exhibited no sink marks or voids. 
The reaction mixture had a setting time of 78 seconds and a rise time of 
108 seconds. The PU foam had a free-foamed density of 66 g/l. 
Example 3 
Component A: a mixture comprising 
42.6 parts by weight of a block polyoxypropylene-polyoxyethylene-polyol 
having a hydroxyl number of 30 and a content of terminal ethylene oxide 
units of 5.9% by weight, based on the weight of the propylene oxide units, 
obtained by alkoxylation of an initiator molecule mixture comprising 
glycerol and water in a weight ratio of 1:0.98, 
43.95 parts by weight of an N,N-dimethyldipropylenetriamine-initiated 
polyoxypropylene (86.5% by weight)-polyoxyethylene (13.5% by 
weight)-polyol having a hydroxyl number of 35, 
3.3 parts by weight of a graft polyether-polyol having a hydroxyl number of 
28, prepared by free-radical, in-situ polymerization of a 
glycerol-initiated polyoxypropylene-polyoxyethylene-polyol as graft base 
and a mixture of styrene and acrylonitrile in a weight ratio of 3:2 for 
formation of the graft (Lupranol.RTM. 4100 from BASF Aktiengesellschaft), 
4.0 parts by weight of a glycerol-initiated polyoxyethylenepolyol having a 
hydroxyl number of 525 and a potassium ion content of 470 ppm, 
2.0 parts by weight of a polyoxypropylene-polyol having a hydroxyl number 
of 386 initiated by means of technical grade tetrapropylenepentamine, 
1.6 parts by weight of ricinoleic acid, 
2.0 parts by weight of water, 
0.15 part by weight of black paste and 
1.0 part by weight of a sterically hindered amine as antioxidant 
(Naugard.RTM. 445). 
Component B: as in Example 1. 
The dashboard was produced by a method similar to that of Example 1, but 
components A and B were mixed in a weight ratio of 100:45. 
The dashboard, demolded after 2.5 minutes, exhibited no sink marks or voids 
in the semirigid PU foam. 
The reaction mixture had a setting time of 77 seconds and a rise time of 
115 seconds. The PU foam had a free-foamed density of 79 g/l. 
Example 4 
Component A: as in Example 2, but the 1 part by weight of 
polyoxypropylene-polyol initiated by means of technical grade tripropylene 
tetramine was replaced by 1 part by weight of an 
N,N'-bis(3-aminopropyl)ethylenediamine-initiated polyoxypropylene-polyol 
having a hydroxyl number of 352. 
Component B: as in Example 1. 
The molding was produced by a method similar to that of Example 1, but 
components A and B were mixed in a weight ratio of 100:44. 
The molding, demolded after 3 minutes, exhibited no sink marks or voids in 
the PU foam. 
The reaction mixture had a setting time of 76 seconds and a rise time of 
110 seconds. The PU foam had a free-foamed density of 76 g/l. The fogging 
value, measured in accordance with DIN 75 201, Method B, was 0.03 mg. 
Comparative Example 
Production of semirigid PU foams 
Component A: a mixture comprising 
82.4 parts by weight of a polyoxypropylene-polyol having a hydroxyl number 
of 400, prepared using an initiator molecule mixture comprising sucrose 
and water, 
3.6 parts by weight of water, 
10.9 parts by weight of cyclopentane, 
2.3 parts by weight of dimethylaminocyclohexylamine and 
0.8 part by weight of a silicone-based foam stabilizer 
(Tegostab.RTM. 8409 from Goldschmidt AG). 
Component B: as in Example 1. 
In order to produce a molding, components A and B were mixed in a weight 
ratio of 100:147.14, and the reaction mixture was transferred into a 
metallic mold and allowed to expand and cure. 
The rigid PU foam molding, demolded after 3 minutes, was brittle and 
unsuitable for industrial use. 
The reaction mixture had a cream time of 14 seconds, a setting time of 54 
seconds and a rise time of 72 seconds. The PU foam had a free-foamed 
density of 25.4 g/l. Example 5 
Component A=a mixture comprising 
84.7 parts by weight of an N,N'-bis(3-aminopropyl)ethylenediamine-initiated 
polyoxypropylene-polyol having a hydroxyl number of 407, 
3.6 parts by weight of water, 
10.9 parts by weight of cyclopentane and 
0.8 part by weight of a silicone-based foam stabilizer (Tegostab.RTM. 8409 
from Goldschmidt AG). 
Component B: as in Example 1. 
The molding was produced by a method similar to that of the Comparative 
Example, but components A and B were mixed in a weight ratio of 
100:151.16. 
The non-brittle rigid PU foam of the industrially suitable molding, which 
was demolded after 3 minutes, was extremely fine-celled. 
The reaction mixture had a cream time of 8 seconds, a setting time of 23 
seconds and a rise time of 37 seconds. The PU foam had a free-foamed 
density of 25.8 g/l.