Note: Descriptions are shown in the official language in which they were submitted.
2161005
~
Production of rigid polyurethane foams having reduced thermal
conductivity, and the use thereof
The present invention relates to a process for the production
of rigid polyurethane (abbreviated to PU below) foams
containing at least 32% by weight of aromatic radicals and thus
further reduced thermal conductivity by reacting a) organic,
preferably aromatic polyisocyanates with b) relatively
high-molecular-weight compounds containing at least two
reactive hydrogen atoms and preferably containing bonded
arylene units, and, if desired, c) low-molecular-weight chain
extenders and/or crosslinking agerlts, in the preserice of d)
blowing agents, preferably blowing agent combinations of
cyclopentane and/or cyclohexane and water, e) catalysts and, if
desired, f) additives, and to the use of these rigid PU foams
for foam-filling cavities in refrigeration equipment or heating
elements and as insulation materials for composite elements.
The production of composite or sandwich elements built up from
a rigid PU foam and at least one outer layer of a rigid or
elastic material, for example paper, plastic film, metal
sheeting, glass nonwovens, chipboard, inter alia, is known.
Also known is the foam-filling of cavities in domesti-c
appliances, such as refrigeration equipment, for example
refrigerators or freezers, or of hot-water starage tanks, by
means of rigid PU foam as insulating material. In order to
prevent foam flaws, the foarnable PU reaction mixtur.e must be
introduced into the cavity to be insulated wit.hin a short time.
Such articles are usually foam-filled using low-pressure or
preferably high-pressure machines.
A review of the production of rigid PU foams and their use as
the outer layer or preferably the core layer in composite
elements and their use as the insulating layer in refrigeration
or heating technology has been published, for example, in
Polyurethane, Kunststoff-Handbuch, Volume 7, l-st Edition 1966,
edited by Dr. R. Vieweg and Dr. A. Hdchtlen, and 2nd Edition
1983, edited by Dr. Giinter Oertel, Carl Hanser Verlag, Munich,
Vienna.
Heat- and cold-insulating rigid PU foams which are su.itable for
this purpose can, as is known, be produced by reactirig organic
polyisocyanates with one or more relatively
216 106 5_
2
high-molecular-weight compounds containing at least two
reactive hydrogen atoms, preferably polyester-- and/or
polyether-polyols, usually in the presence of
low-molecular-weight chain extenders and/or crosslinking
agents, in the presence of blowing agents, catalysts and, if
desired, auxiliaries and/or additives. A suitable choice of the
formative components allows the prodtiction of rigid PU foams
having a low thermal conductivity and good mechanical
properties.
Blowing agents which have been used worldwide in large amounts
for the productiori of heat- and cold-insulatirig rigid PU foams
are chlorofluorocarborls (CFCs), preferably
trichlorofluoromethane. The only disadvantage of these blowing
gases is that they are suspected of causing erivironmental
pollution by participating in degradation of the ozone layer in
the stratosphere.
There has therefore been no lack of attempts to replace CFCs by
blowing agents which cause little or preferably no
environmental damage.
According to EP-A---351 614 (US.--A-4,972,002), the blowing agents
can be fluorinated hydrocarbons, perfluorinated hydrocarbons,
sulfur hexafluoride or mixtures of at least, two of these
compounds. Since these fluorinated or perfluorinated blowing
agents are only sparirigly soluble or insoluble in the formative
components for the preparation of the polyisocyanate
polyaddition products, they are emulsified in at least one
organic and/or modified organic polyisocyanate, at least orie
relatively high-molecular-weight compound containing at least
two reactive hydrogen atoms or a mixture of at: least one
relatively high-molecular-weight compound containing at least
two reactive hydrogen atoms and a low-molecular-weight chain
extender and/or crosslinking agent. This method gives cellular
plastics having a uniform and fine cell structure. The only
disadvantages of this process are the r.estri.cted cho:i-ce of
suitable fluorinated or perfluorinated compourids having a
boiling point in the requisite range arid the high price of
these blowing agents. The production of cellulLar plastics
having the cell structure desired by industry has to rely on a
highly restricted range of mixtures of perfluoropentane and
perfluorohexane.
216 106 5
3
The production of cellular plastics by the polyisocyanate
polyaddition process is, according to DE-A-41 43 148, also
highly successful usirig blowing agents (d), if desired in
combination with water, which contain at least: one low-boiling,
fluorinated or perfluorinated organic compounci which is
sparingly soluble or insoluble in formative components (a), (b)
and (c) and at least one isoalkane having 6 tc> 12 carbon atoms.
Rigid PU foams having low thermal conductivity are furthermore
described in EP-A-O 421 269 (US-A-5,096,933). The blowing
agents used, preferably in combination with water, are
cyclopentane or mi.xtures, expediently having a boiling point of
below 500C, containing:
cyclopentane and/or cyclohexane and at least one inert,
low-boiling compound which is homogeneously miscible with
cyclopentane and/or cyclohexane, preferably from the group
consisting of alkanes, cycloalkanes having a niaximum of 4
carbon atoms, dialkyl ethers, cycloalkylene ethers and
fluoroalkanes.
A suitable choice of blowing agent, which remains in the rigid
PU foam for a considerable period as cell gas, since its
diffusion rate is very low, in particular if the foam is
provided on all sides with plastic or metal outer layers,
allows a significant reduction in the thermal conductivity of
the rigid PU foam.
Since heat transport from a warm to a cold point in ei foam can
take place, for example, via the foam matrix, the cell gas or
by radiation, there is still a need to minimize the thermal
conductivity of rigid PU foam by suitable measures and thus to
reduce the energy consumption, for example in refrigeration
equipment, or the release of heat, for example by (remote)
heating systems and hot--water storage tanks by means of
insulation elements.
It is an object of the present invention further to reduce the
thermal conductivity of the PU foams while substantially
avoiding the use of toxic and/or environmentally damaging
blowing agents. The polyol and polyisocyanate components (A)
and (B) shoul.d have a long shelf life, and the reaction mixture
for the production of the rigid PU foams shoul.d be very
free-flowing and should cure without shrinkage. During
CA 02161065 2007-08-14
4
foam-filling of casing parts, a strong bond between the outer
layer and the rigid PU foam should be formed.
We have found that, surprisingly, this object is achieved by
using organic polyisocyanates and/or relatively
high-molecular-weight or low-molecular-weight compounds which
are reactive with NCO groups and contain at least two reactive
hydrogen atoms and bonded aromatic radicals.
The present invention accordingly provides a process for the
production of rigid polyurethane foams having low thermal
conductivity by reacting
a) organic and/or modified organic polyisocyanates with
b) at least one relatively high-molecular-weight compound
containing at least two reactive hydrogen atoms and,
optionally,
c) low-molecular-weight chain extenders and/or crosslinking
agents,
in the presence of
d) blowing agents,
e) catalysts and, optionally,
f) additives,
wherein the process further comprises incorporating at least 32% by weight,
preferably at least 33 to 50% by weight, or more preferably from 34 to 40% by
weight, based on the rigid polyurethane foams, of aromatic radicals
incorporated
in formative components (a), (b) and/or, if used, (c) or in at lest two of the
formative components (a), (b) and/or if used, (c).
In a preferred embodiment, the organic polyisocyanates (a),
preferably aromatic polyisocyanates, and the relatively
high-molecular-weight compounds (b) used in the novel process
for the production of the rigid PU foams containing at least
32% by weight of aromatic radicals are preferably those
containing arylene radicals, so that formative components (a)
and (b) introduce aromatic radicals into the rigid PU foam
21s1 fi5
matrix. In other process variants, however, the content of at
least 32% by weight of aromatic radicals in the rigid PU foam
can result exclusively from the aromatic polyisocyanates (a) or
exclusively from the relatively high-molecular-weight compounds
(b) and/or low-molecular-weight chain extenders and/or
crosslinking agents.
The novel process allows the thermal conductivity of the rigid
PU foams to be reduced by at least 0.5 mW/mK, usually by from 1
to 2 mW/mK under otherwise identical conditior.is. However, the
increase in the aromatic content in the rigid PU foam not only
reduces the thermal conductivity, but also improves its
mechanical properties in general, specifically the flame
resistance and the aging behavior. It is f_urthermore
advantageous that the compatibility and miscibility of
formative components (a), (b), (e) and, if used, (c) and/or (f)
with one another and with the blowing agents (d) preferably
used, for example alkanes arid/or in particular cycloalkanes, is
increased and the flowability of the reaction mixture is
extended.
The rigid PU foams can be produced by the novel process using
the formative components known per se, preference bei-ng given
to those having a high content of aromatic groups in order to
achieve a content of at least 32% by weight in the rigid PU
foam. However, it is also possible to use formative components
(a) to (c) containing no aromatic groups as a mixture with the
formative components preferably containing bor.ided aromatic
groups or as the only starting material, with the proviso that
the rigid PU foams formed contain at least 321; by weight of
bonded aromatic radicals.
The following details apply to the formative componerits:
a) Suitable organic polyisocyanates are the aliphatic, cyclo-
aliphatic, araliphatic and preferably aromatic polyiso-
cyanates known per se.
The following may be mentioned as examples: alkylene diiso-
cyanates having from 4 to 12 carbon atoms in the alkylene
moiety, such as 1,12--dodecane diisocyanate, 2-ethyltetra-
methylene 1,4-diisocyanate, 2-methylpentarnethylene
1,5-diisocyanate, 2-ethyl--2-butylpentamethylene 1,5-diiso-
cyanate, tetramethylene 1,4-diisocyanate and preferably
216 106 5
6
hexamethylene 1,6--diisocyanate; cycloaliplzatic diisocya-
nates, such as cycl.ohexane 1,3- and 1,4-diisocyanate and
any desired mixtures of these isomers, 1-.Lsocyana-
to-3,3,5-trimethy:l- 5-isocyanatomethylcyc:lohexane (isopho-
rone diisocyariate), 2,4-- and 2,6-hexahydrotolylene diisocy-
anate, and the corresponding isomer mixtures, 4,4'-, 2,2'-
and 2,4'-dicyclohexylmethane diisocyariate and the corre-
sponding isomer mixtures, araliphatic diisocyanates, for
example 1,4--xylylene diisocyanate and xylylene diisocyanate
isomer mixtures, and preferably aromatic diisocyanates and
polyisocyanates, eg. 2,4- and 2,6-tolylene diisocyanate and
the corresponding isomer mixtures, 4,4'-, 2,4'- and
2,2'-diphenylmethane diisocyanate and the corresponding
isomer mixtures, mixtures of 4,4'- and 2,4'-diphenylmethane
diisocyanates, po].yphenyl-polymethylene polyisocyanates,
mixtures of 4,4'-, 2,4'- and 2,2'-dipheny]Lmethane diisocya-
nates and polyphenyl-polymethylene polyisocyanates (crude
MDI), and mixtures of crude MDI and tolylene diisocyanates.
The organic diisocyanates and polyisocyanates may be
employed individually or in the form of mixtures.
The organic polyisocyanates can be prepared by known pro-
cesses. They are preferably prepared by phosgenation of the
corresponding polyamines with formation of polycarbamoyl
chlorides, and thermolysis thereof to give the organic
polyisocyanate anci hydrogen chloride, or by phosgene-free
processes, for example by reacting the corresponding poly-
amines with urea and alcohol to give polycarbamates, and
thermolysis thereof to give the polyisocyanate and alcohol.
Frequently, modified polyisocyanates are also used, ie.
products which are obtained by chemical reaction of organic
diisocyanates and/or polyisocyanates. Specific examples are
ester-, urea-, biuret-, allophanate-, uretoneimine-, carbo-
diimide-, isocyanurate-, uretdione- and/or urethane-
containing diisocyanates and/or polyisocyanates. Individual
examples are urethane-containing organic, preferably aro-
matic, polyisocyariates containing from 33.6 to 15% by
weight, preferably from 31 to 21% by weight, of NCO, based
on the total weight, for example 4,4'-diphenylmethane diis-
ocyanate, 4,4'- and 2,4'-dipheriy.lmethane diisocyanate mix-
tures, or crude MDI or 2,4- or 2,6-to.lylerie diisocyanate,
in each case modified by means of low-molecular-weight
diols, triols, dialkylene glycols, trialkylene glycols or
216 106 5 _
7
polyoxyalkylen.e glycols having molecular weights of up to
6000, specific examples of di- and polyoxyalkylene glycols,
which can be employed individually or as mixtures, being
diethylene, dipropylene, polyoxyethylene, polyoxypropylene
and polyoxypropylene--polyoxyethylene glycols, triols and/or
tetrols. NCO-containing prepolymers containing from 25 to
3.5% by weight, preferably from 21 to 14% by weight, of
NCO, based on the total weight, and prepared from the poly-
ester- and/or preferably polyether-polyols described below
and 4,4'-diphenylrnethane diisocyanate, mixtures of 2,4'-
and 4,4'-diphenylrnethane diisocyanate, 2,4- and/or 2,6-to-
lylene diisocyanates or crude MDI are also suitable. Fur-
thermore, liquid polyisocyanates containing carbodiimide
groups and/or isocyanurate rings and containing from 33.6
to 15% by weight, preferably from 31 to 2:1% by weight, of
NCO, based on the total weight, eg. based on 4,4'-, 2,4'-
and/or 2,2'-diphenylmethane diisocyanate and/or 2,4- and/or
2,6-tolylene diisocyanate, have also proven successful.
The modified polyisocyanates may be mixed with one another
or with unmodified organic polyisocyanates, eg. 2,4'- or
4,4'-diphenylmethane diisocyanate, crude MDI or 2,4- and/or
2,6-tolylene diisocyanate.
Organic polyisocyanates which have proven particularly
successful and are therefore preferred for the production
of the rigid PU foams are: mixtures of modified organic
polyisocyanates containing urethane groups, having an NCO
content of from 33.6 to 15% by weight, in particular those
based on tolylene diisocyanates, 4,4'-diphenylmethane diis-
ocyanate, diphenylmethane diisocyanate isomer mixtures or
crude MDI, in part:icular 4,4'-, 2,4'-- and 2,2'-diphenylme-
thane diisocyanate, polyphenyl-polymethyl(ane polyisocya-
nates, 2,4- and 2,6-tolylene diisocyanate, crude MDI having
a diphenylmethane diisocyanate isomer content of from 30 to
80% by weight, preferably from 35 to 45% by weight, and
mixtures of at least two of the said polyisocyanates, for
example crude MDI or mixtures of tolylene diisocyanates and
crude MDI.
b) The relatively high-molecular-weight compounds (b) contain-
ing at least two reactive hydrogen atoms are preferably
polyhydroxyl compounds having a functionality of from 2 to
216 yo6 5
8
8, preferably 3 to 8, and a hydroxyl number of from 100 to
850, preferably from 120 to '770.
Examples which may be mentioned are polythioether-polyols,
polyester-amides, hydroxyl-containing polyacetals and
hydroxyl-containing aliphatic polycarbonates, and
preferably polyester-polyols and polyether-polyols. Use is
also made of mixtures of at least two of the said
polyhydroxyl compourids and with polyhydroxyl compounds
having hydroxyl numbers of less than 100, so long as the
mixtures have a mean hydroxyl number in the above range.
Suitable polyester-polyols may be prepared, for example,
from organic dicarboxyl.ic acids having from 2 to 12 carbon
atoms, preferably aromatic dicarboxylic acids having from 8
to 12 carbon atoms and polyhydric alcohols, preferably
diols, having from 2 to 12 carbon atoms, preferably from 2
to 6 carbon atoms. Examples of suitable dicarboxylic acids
are succinic acid, glutaric acid, adipic acid, suberic
acid, azelaic acid, sebacic acid, decanedicarboxylic acid,
maleic acid, fumaric acid and preferably phthalic acid,
isophthalic acid, terephthalic acid and the isomeric naph-
thalenedicarboxylic acids. The di.carboxylic acids may be
used either individually or mixed with one another. The
free dicarboxylic acids may also be replaced by the corre-
sponding dicarboxylic acid derivatives, for example dicar-
boxylic esters of alcohols having 1 to 4 carbon atoms or
dicarboxylic anhydri.des. Preferetlce .i.s given to dicarboxyl-
ic acid mixtures comprising succinic acid, glutaric acid
and adipic acid in ratios of, for example, from 20 to 35
to 50 : 20 to 32 parts by weight, and adipic acid, and
in particular mixtures of phthalic acid and/or phthalic
anhydride and adipic acid, mixtures of phthalic acid or
phthalic anhydride, isophthalic acid and adipic acid or
dicarboxylic acid mixtures of succinic acid, glutaric acid
and adipic acid and mixtures of terephthalic acid and
adipic acid or dicarboxylic acid mixtures of succinic acid,
glutaric acid and adipic acid. Examples of dihydric and
polyhydric alcohols, in particular diols, are ethanediol,
diethylene glycol, 1,2- and 1,3-propanediol, dipropylene
glycol, 1,4-butanediol, 1,5-pentanedio:l, 1,6-hexanediol,
1,10-decanediol, glycerol, trimethylol.propane. Preference
is given to ethanediol, diethylene glycol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol or mixtures of at least two
21fi1qfi5
9
of said diols, in particular mixtures of 1,4-butanedi_ol,
1,5-pentanediol and 1,6-hexanediol. Furthermore, polyester-
polyols made from lactones, eg. e-caprolactone or hydroxy-
carboxylic acids, e.g. w-hydroxycap.roic acid and. hydroxy-
benzoic acids, may also be employed.
The polyester-polyols may be prepared by polycondensing the
organic, eg. aliptiatic and preferably aromatic polycarbox-
ylic acids and mixtures of aromatic and a:liphatic poly--
carboxylic acids, and/or derivatives thereof, and polyhyd-
ric alcohols without using a catalyst or preferably in the
preserice of arz esterification catalyst, expediently in an
inert gas atmosphere, eg. nitrogen, carbon monoxide, he-
lium, argon, inter alia, in the melt at f_rom 150 to 250 C,
preferably from 180 to 220 C, at atmospheric pressure or
under reduced pressure until the desi.red acid number, which
is advantageously less than 10, preferably less than 2, is
reached. In a preferred embodiment, the esterification mix-
ture is polyconderised at the abovementioned temperatures
under atmospheric pressure and subsequently unde:r a pres-
sure of less than 500 mbar, preferably from 50 to 150 mbar,
until an acid number of from 80 to 30, preferably from 40
to 30, has been reached. Examples of suitable esterifica-
tion catalysts are iron, cadmium, cobalt, lead, zinc, anti-
mony, magnesium, t:itanium and tin catalysts in the form of
metals, metal oxides or metal salts. However, the polycon-
densation may also be carried out in the liquid phase in
the presence of diluents and/or entrainers, eg. benzene,
toluene, xylene or chlorobenzene, for removal of the water
of condensation by azeotropic distillation.
The polyester-polyols are advantageously prepared by poly-
condensing the organic polycarboxyli.c acids and/or deriva-
tives thereof with polyhydric alcohols in a molar ratio of
from 1:1 to 1.8, preferably from 1:1.05 to 1.2.
The polyester-polyols obtained preferably have a furictiona-
lity of from 2 to 3 and a hydroxyl number of from 150 to
600, in particular from 200 to 400.
However, the polyhydroxyl compounds used are in particular
polyether-polyols prepared by known processes, for example
by anionic polymerization using alkali metal hydroxides
such as sodium hydroxide or potassium hydroxide, or alkali
216 1 6 5
metal alkoxides, such as sodium methoxide, sodium ethoxide,
potassium ethoxide or potassium isopropoxide as catalysts
and with addition of at least one initiator molecule con-
taining from 2 to 8, preferably 3 to 8, reactive hydrogen
atoms in bound form or by cationic polymerization using
Lewis acids, such as aritimony pentachloride, boron fluoride
etherate, inter alia, or bleaching earth as catalysts, from
one or more alkylene oxides having from 2 to 4 carbon atoms
in the alkylene moiety.
Examples of suitable alkylene oxides are tetrahydrofuran,
1,3-propylene oxicie, 1,2- and 2,3-butylene oxide, styrene
oxide and preferably ethylene oxide and 1,.2-propylene ox-
ide. The alkylene oxides may be used individually, alterna-
tively one after the other or as mixtures. Examples of
suitable initiator molecules are water, organic di.carboxyl-
ic acids, such as succinic acid, adipic acid, phthalic acid
and terephthalic acid, aliphatic and aromatic, unsubsti-
tuted or N-mono-, N,N- and N,N'-dialkyl-substituted dia-
mines having from 1 to 4 carbon atoms in the alkyl moiety,
such as unsubstituted or mono- or dialkyl--substituted ethy-
lenediamine, diethylenetriamine, triethylenetetramine,
1,3-propylenediamine, 1,3- and 1,4-butyleriediamine, 1,2-,
1,3-, 1,4-, 1,5- and 1,6-hexamethylenediamine, aniline,
phenylenediamines, 2,3-, 2,4--, 3,4- and 2,6-toly:lenediamine
and 4,4'-, 2,4'- and 2,2'-diaminodiphenylmethane.
Other suitable initiator molecules are alkanolamines, eg.
ethanolamine, N-methyl- and N-ethylethanolamine, dialkanol-
amines, eg. diethanolamine, N-methyl- and N-ethyldiethanol-
amine, and trialkanolamines, eg. triethanolamirie, and
ammonia, and polyhydric alcohols, in particular dihydric
and/or trihydric alcohols, such as ethanediol, 1,2- and
1,3-propanediol, diethylene glycol, dipropylene glycol,
1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpro-
pane, pentaerythritol, sorbitol and sucrose, polyhydric
phenols, for example 4,4'-dihydroxydiphenylmethane and
4,4'-dihydroxy-2,?,-diphenylpropane, resols, for example
oligomeric products of the conderisation oi= phenol and
formaldehyde, and Mannich condensates of phenols, formalde-
hyde and dialkanolamines, and melamine.
_
216 106 5
11
The relatively high-molecular-weight compaunds (b) are ad-
vantageously polyether-polyols having a functionality of
from 2 to 8 and a hydroxyl number of from 100 to 850 pre-
pared by anionic polyaddition of at least one alkylene
oxide, preferably ethylene oxide or 1,2-propylene oxide or
1,2--propylene oxide and ethylene oxi.de, onto, as initiator
molecule, at least: one aromatic compound containing at
least two reactive hydrogen atoms and containing at least
one hydroxyl, amirro and/or carboxyl group. Examples which
may be rnentioned of such initiator molecules are aromatic
polycarboxylic acids, for example hemimellitic acid, tri-
mellitic acid, tri-mesic acid and preferably phthalic acid,
isophthalic acid and terephthalic acid, oi.- mixtures of at
:least two of said polycarboxylic acids, hydroxycarboxylic
acids, for example salicylic acid, p- and m-hydroxybenzoic
acid and gallic acid, aminocarboxylic acids, for example
anthranilic acid, m- and p-aminobenzoic acid, polyphenols,
for example resorcinol, and preferably dihydroxydiphenyl-
methanes and dihyciroxy-2,2-diphenylpropanes, Mannich con-
densates of pheno]-s, formaldehyde and dia]Lkanolamines, pre-
ferably diethanolamine, and preferably aromatic polyamines,
for example 1,2-, 1,3- and 1,4-phenylenedaamine and in par-
ticular 2,3-, 2,4--, 3,4-- and 2,6-tolylenediamine, 4,4'-,
2,4'- and 2,2'-diaminodiphenylmethane, polyphenyl-polyme-
thylene-polyamines, mixtures of diaminodiphenylmethanes and
polyphenyl-polymethylene-polyamines, as formed, for
example, by conderisation of aniline with formaldehyde, and
mixtures of at least two of said polyamines.
The preparation of polyether-polyols usinq at least difunc-
tional aromatic iriitiator molecules of thiLs type is known
and is described, for example, in DD-A-290 201,
DD-A-290 202, DE-A-34 12 082, DE-A--4 232 970 and
GB-A-2,187,449.
The polyether-polyols preferably have a functionality of
from 3 to 8, in particular from 3 to 6, and hydroxyl
numbers of from 120 to 770, in particular from 240 to 570.
Other suitable pol.yether-polyols are melanline/po_lyether-
polyol dispersions as described in EP-A--23 987
(US-A-4,293,657), polymer/polyether-polyol dispersions pre-
pared from po].yepoxides and epoxy resin curing agents in
the presence of polyether-polyols, as described in
CA 02161065 2006-07-27
12
DE 29 43 689 (US 4,305,861), dispersions of aromatic poly-
esters in polyhydroxyl compounds, as described in
EP-A-62 204 (US-A-4,435,537) and DE-A 33 00 474, disper-
sions of organic and/or inorganic fillers in polyhydroxyl
compounds, as described in EP-A-11 751 (US 4,243,755),
polyurea/polyether-polyol dispersions, as described in
DE-A-31 25 402, tris(hydroxyalkyl) isocyanurate/polyether-
polyol dispersions, as described in EP-A-136 571
(US 4,514,526), and crystallite suspensions, as described
in DE-A-33 42 176 and DE-A-33 42 177 (US 4,560,708).
Like the polyester-polyols, the polyether-polyols can be
used individually or in the form of mixtures. Furthermore,
they may be mixed with the graft polyether-polyols or poly-
ester-polyols and the hydroxyl-containing polyester-amides,
polyacetals, polycarbonates and/or phenolic polyols.
Examples of suitable hydroxyl-containing polyacetals are
the compounds which can be prepared from glycols, such as
diethylene glycol, triethylene glycol, 4,4'-dihydroxyethox-
ydiphenyldimethylmethane, hexanediol and formaldehyde.
Suitable polyacetals can also be prepared by polymerizing
cyclic acetals.
Suitable hydroxyl-containing polycarbonates are those of a
conventional type, 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 gly-
col or tetraethylene glycol, with diaryl carbonates, eg.
diphenyl carbonate, or phosgene.
The polyester-amides include, for example, the predominant-
ly linear condensates obtained from polybasic, saturated
and/or unsaturated carboxylic acids or anhydrides thereof
and polyhydric, saturated and/or unsaturated amino alco-
hols, or mixtures of polyhydric alcohols and amino alcohols
and/or polyamines.
Suitable relatively high-molecular-weight compounds (b)
containing at least two reactive hydrogen atoms are
furthermore phenolic and halogenated phenolic polyols, for
example resol-polyols containing benzyl ether groups.
2 6~06 5-,
13
Resol-polyols of t:his type can be prepared, for example,
from phenol, formaldehyde, expedient.ly par_aformaldehyde,
and polyhydric aliphatic alcohols and are described, for
example, in EP-A-0 116 308 and EP-A-0 116 310.
The relatively high-molecular-weight compounds (b) are in
particular mixtures of polyether-polyols c:ontain:ing at
least one polyether-polyol based ori an aromatic, polyfunc-
tional initiator nlolecule and at least one polyether-polyol
based on a nonaromatic initiator molecule, preferably a
trihydric to octahydric alcohol.
c) The rigid PU foams can be produced with or without the use
of chain extenders and/or crosslinking agents. However, it
may prove advantageous, in order to modify the mechanical
properties, to add difunctional chain extenders, trifunc-
tional or polyfunctional. crosslinking agerits or, if de--
sired, mixtures thereof. Examples of chain extenders and/or
crosslinking agents are alkanolamines, in particular diols
and/or triols, having molecular weights of less than 400,
preferably from 60 to 300. Examples are alkanolamines, for
example ethanolamine and/or isopropanolami_ne, dialkanol-
amines, for example diethanolamine, N-methyl and N-ethyl-
diethanolamine, di.isopropanolamine, trialkanolamines, for
example triethanolamine, and triisopropanolamine, and the
products of the addition reaction of ethylene oxide or
1,2-propylene oxicie and alkylenediamines having 2 to 6
carbon atoms in the alkylene radical, for example
N,N,N',N'-tetra (2--hydroxyethyl) ethyl.enediamine and
N,N,N',N'-tetra(2--hydroxypropyl)ethylened:iamine, aliphatic,
cycloaliphatic and/or araliphatic diols having from 2 to 14
carbon atoms, preferably from 4 to 10 carbon atorns, eg.
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, triols, such as 1,2,4-. and
1,3,5-trihydroxycyclohexane, glycerol and trimethylolpro-
pane, and low-molecular-weight hydroxyl-containing polyal-
kylene oxides based on ethylene oxide and/or 1,2-propylene
oxide and aromatic diamines, for example tolylenediamines
and/or diaminodiphenylmethanes, and the abovementioned
alkanolamines, diols and/or triols as initiator rnolecules.
2161065
14
Any chain extenders, crosslinking agents or mixtures there-
of used for the production of the rigid PU foams are ex-
pediently used in an amount of from 0 to 20% by weight,
preferably from 2 to 5% by weight, based on the weight of
the polyhydroxyl compound.
d) The blowing agent for the production of the rigid PU foams
is preferably cyclopentane (dl). However, good results have
also been achieved usirig mixtures (d2) coritaining
(d2i) cyclopentane, cyclohexane or a mixture of these
cycloalkanes and
(d2ii) at least orie low-boiling compourid, preferably having a
boiling point of below 40'C, which is homogeneously
miscible with cyclopentane and/or cyclohexane.
The compounds of said type which are suitable as blowing
agent can be selected from the group consi_sting of alkanes,
cycloalkanes having a maximum of 4 carbon atoms, dialkyl
ethers, cycloalkylene ethers and fluoroalkanes. :[t is also
possible to use mixtures of at least two compounds of said
groups of compound. Specific examples which may be men-
tioned are: alkanes, for example propane, n-butane, iso-
butane, n- and isopentane and technical-grade pentane mix-
tures, cycloalkanes, for example cyclobutane, dialkyl
ethers, for example dimethyl ether, methyl ethyl ether,
methyl butyl. ether and diethyl ether, cycloalkylene ethers,
for example furan, and fluoroalkanes which are broken down
in the troposphere and therefore do not damage the ozone
layer, for example t.rifluoromethane, difluoromethane,
difluoroethane, tetrafluoroethane and heptafluoropropane.
The preferred blowing agents can be used alone or prefer-
ably in combination with water, the following cornbinations
having proven highly successful and are therefore pre-
ferred: water and cyclopentane, water and cyclopentane or
cyclohexane or a niixture of these cycloalkanes and at least
one compound from the group consisting of n-butane, iso-
butane, n- and isopentane, technical-grade peritane mix-
tures, cyclobutane, rnethyl butyl ether, diethyl ether,
furan, trifluoromethane, difluoromethane, difluoroethane,
tetrafluoroethane and heptaf].uoropropane. The amount of
low-boiling compounds which are homogeneously miscible with
216 10,65
cyclopentane and/or cyclohexane used in combination with
cyclohexane and iri particular with cyclopentane is such
that the resultant: mixture advantageously has a boiling
point of below 50"C, preferably from 30 to 0'C. The requi-
site amount depencls on the course of the boiling--point
curve of the mixture and can be determined experimentally
by known methods. Rigid PU foams having low conductivity
are obtained, in particular, if the blowirig agent (d) used
is, per 100 parts by weight of forrnative component (b):
dl) from 3 to 22 parts by weight, prefera:bly from 5 to 18
parts by weight, in particular from 8 to 14 parts by
weight, of cyclopentane and from 0 to 7 parts by
weight, preferably from 1.0 to 5.0 parts by weight, in
particular from 2.2 to 4.5 parts by weight, of water or
d2i) from 2 to 22 parts by weight, preferalbly from 5 to 19
parts by weight, in particular from 9 to 19 parts by
weight, of cyclopentane and/or cyclohexane,
d2ii) from 0.1 to 18 parts by weight, preferably from 0.5 to
10 parts by weight, in particular froin 1.0 to 6.0 parts
by weight, of at least one compound having a boiling
point of below 400C which is homogeneously miscible
witti cyclopentane and/o.r cyclohexane, selected from the
group consisting of alkanes, cycloalkanes having a
maximum of. 4 carbon atoms, dialkyl ethers,
cycloalkylene ethers and preferably fluoroalkanes, and
from 0 to 7 parts by weight, preferably from 1.0 to 5.0
parts by weight, in particular from 2.2 to 4.5 parts by
weight, of water.
In order to produce the rigid PU foams, the cyclopentane
(dl) or the blowirig agent mixture (d2), preferably in com-
bination with water, is introduced by knovm methods into at
least one formative component (a) to (c) f:or the production
of the rigid P[J foam, if desired under pressure, or
introduced directly into the reaction mixture, expediently
by means of a suitable mixing device.
CA 02161065 2006-07-27
16
Blowing agents of said type are described, for example, in
EP-A-O 421 269 (US-A-5,096,933).
Other suitable blowing agents are blowing-agent-containing
emulsions with a long shelf life which contain at least one
low-boiling, fluorinated or perfluorinated hydrocarbon hav-
ing 3 to 8 carbon atoms which is sparingly soluble or in-
soluble in formative components (a) to (c), sulfur hexa-
fluoride or mixtures thereof, and at least one formative
component (a), (b) or (c) as described in EP-A-O 351 614 or
emulsions of mixtures of the abovementioned low-boiling,
fluorinated or perfluorinated hydrocarbon having 3 to 8
carbon atoms which is sparingly soluble or insoluble in the
formative components (a) to (c), and at least one isoalkane
having 6 to 12 carbon atoms or cycloalkane having 4 to 6
carbon atoms and at least one formative component (a), (b)
or (c), for example as described in DE-A-41 43 148.
e) The catalysts (e) used are, in particular, compounds which
greatly accelerate the reaction of the hydroxyl-containing
compounds of components (b) and, if used, (c) with the
polyisocyanates. Suitable compounds are organometallic com-
pounds, preferably organotin compounds, such as tin(II)
salts of organic carboxylic acids, eg. tin(II) diacetate,
tin(II) dioctanoate, tin(II) diethylhexanoate and tin(II)
dilaurate, and dialkyltin(IV) salts of organic carboxylic
acids, eg. dibutyltin diacetate, dibutyltin dilaurate, di-
butyltin maleate and dioctyltin diacetate. The organometal-
lic compounds can be employed alone or preferably in com-
bination with highly basic amines. Examples which may be
mentioned are amidines, such as 1,8-diazabicyclo[5.4.0]un-
dec-7-ene, 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, ter-
tiary amines, such as triethylamine, tributylamine, dime-
thylbenzylamine, N-methyl-, N-ethyl-, N-cyclohexylmorpho-
line, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-
tetramethylbutanediamine or -hexanediamine, pentamethyl-
diethylenetriamine, tetramethyldiaminoethyl ether, bis(di-
methylaminopropyl)urea, dimethylpiperazine, 1,2-dimethyli-
midazole, 1-azabicyclo[3.3.0]octane, and, preferably,
1,4-diazabicyclo[2.2.2]octane and alkanolamine compounds
such as triethanolamine, triisopropanolamine, N-methyl- and
N-ethyldiethanolamine and dimethylethanolamine.
2161065
17
Other suitable catalysts are: tris(dialkylaminoa.lkyl)-
s-hexahydrotriazines, in particular 1,3,5--tris(N,N-di-
methylaminopropyl)-s-hexahydrotriazi.ne, tetraalkylammonium
hydroxides, such as tetramethylammonium hydroxide, alkali
metal hydroxides, such as sodium hydroxide, and alkali
metal alkoxides, such as sodium methoxide and potassium
isopropoxide, and alkali metal salts of long-chain fatty
acids having 10 tc> 20 carbon atoms and possibly pendant OH
groups. Preference is given to 0.001 to 5% by weight, in
particular from 0.05 to 2.5% by weight, of_ catalyst or
catalyst combination, based on the weight of component (b).
f) The reaction mixture for the production of the rigid PU
foams may also be adrnixed with additives (f) conventional
in polyurethane chemistry. Additives which may be mentioned
are surfactants, foam stabilizers, cell regulators,
fillers, dyes, pigments, flameproofing agents, antistatics,
hydrolysis-protection agents, and fungistatic and bacterio-
static substances.
Suitable surfactants are, for example, conipounds which
support homogenization of the starting materials and may
also be suitable f:or regulating the cell structure. Exam-
ples which may be mentioned are emulsifiers, such as the
sodium salts of castor oil sulfates, or of' fatty acids and
salts of fatty acids with amines, for example diethylamine
oleate, diethariolamine stearate, diethanolamine ricino-
leate, salts of sulfonic acids, for example alkali metal or
ammonium salts of dodecylbenzene- or dinaphthylmethanedi-
sulfonic acid and ricinoleic acid; foam st:abilizers, such
as siloxane-oxyalkylene copolymers and other organopolysi-
loxanes, oxyethylated alkylpherlols, oxyethylated fatty
alcohols, paraffiri oils, castor oil esters, ricinoleic acid
esters, Turkey reci oil and groundnut oil and cell regula-
tors, such as paraffins, fatty alcohols and dimethyl poly-
siloxanes. Suitable compounds for impr_ovirig the emulsi-
fication action, the cell structure arid/or stabi:Lizing the
rigid foam are furthermore oligomeric polyacrylates con-
taining 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
component (b).
2161065
18
For the purposes of the present invention, fillers, in
particular reinforcing fillers, are conventional organic
and inorganic fillers, reiriforcing agerits and weighting
agents. Specific examples are inorgariic fillers, such as
silicate minerals, for example phyllosilicates, such as
antigorite, serpentine, hornbl.ende, amphiboles, chrysotile,
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
1.0 as cadmium sulfide, zinc sulfide and glass. Examples of
suitable organic fillers are: carbori black, melamine,
colophony, cyclopentadienyl resins and graft polymers.
The inorganic and organic fillers may be used individually
or as mixtures and are advantageously introduced 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
components (a) to (c).
20 Examples of suitable flameproofing agents are tricresyl
phosphate, tris(2--chloroethyl) phosphate, tris(2-chloro-
propyl) phosphate, tris(1,3--dichl.oropropyl) phosphate,
tris(2,3-dibromopropyl) phosphate and tetrakis(2-chloro-
ethyl)ethylene diphosphate.
In addition to the abovementioned halogen--substituted phos-
phates, it is also possible to use inorganic flameproofing
agents, such as red phosphorus, preparations containing red
phosphorus, aluminum oxide hydrate, antimony trioxide,
30 arsenic oxide, ammonium polyphosphate and calcium sulfate,
or cyanuric acid derivatives, eg. melamine, or mixtures of
two or more flameproofing agents, eg. ammonium polyphos-
phates and melamine, and also, if desired, starch, in order
to flameproof the rigid PU foams produced by the novel pro-
cess. 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 f.lamep.roofing agents or mixtures per
100 parts by weight of components (a) to (c).
40 Further details on the other conventional auxiliaries and
additives mentioned above can be obtained from the special-
ist literature, for example from the monograph by
J.H. Saunders and K.C. Frisch in High Polymers, Volume XVI,
Polyurethanes, Parts 1 and 2, Interscience Publishers 1962
2161065
19
and 1964 respectively, or Kunststoff--Handbuch, Polyure-
thane, Volume VII, Carl-Hanser--Verlag, Munich, Vienna, lst
and 2nd Editioris, 1966 and 1.98:3.
In order to produce the rigid PU foams, the organic, modified
or unmodified polyisocyariates (a), the relatively high-molecu-
lar-weight compounds containing at least two reactive hydrogen
atoms (b) and, if used, chain extenders arid/or crosslinking
agents (c) are reacted in such amounts that the ratio between
the number of equivalents of NCO groups iri the pol.yisocyanates
(a) and the total number of reactive hydrogen atoms in compo-
nents (b) and, if used, (c) is from 0.85 to 1.80:1, preferably
from 0.95 to 1.35:1, in particular from about 1.0 to 1.15:1. If
the foams containing urethane groups have beer.i modified by the
formation of isocyanurate groups, for example in order to in-
crease the flame retardarrcy, the ratio bet-weer.t the NC:O groups
in the polyisocyanates (a) and the total number of reactive
hydrogen atoms in component (b) and, if used, (c) is usually
from 1.8 to 10:1, preferably from 2.0 to 6:1.
The rigid PU foams can be produced batchwise or continuously by
the prepolymer process or preferably by the one-shot process
with the aid of known mixing equipmerit.
It has proven particularly advantageous to use the two-compo-
nent process and to combine formative components (b), (d), (e)
and, if used, (c) and (f) in componerrt (A) and to use the
organic polyisocyanates or modified polyisocyanates (a) or mix-
tures of said polyisocyanates and, if desired, blowing agents
(d) as component (B).
The starting components are mixed at from 15 to 90 C,
preferably from 20 to 35 C, and introduced into an open,
unheated or temperature-controlled mold, in which the reaction
mixture is allowed to expand essentially without pressure in
order to avoid a compacted peripheral zone. In order to form
composite elements, the reverse of arr outer layer is
expediently coated, for example by pouring or spraying, with
the foamable reaction inixture, which is allowed to expand and
cure to give the rigid Pt1 foam.
The rigid PU foams containing at least 32% by weight,
preferably at least 33% by weight, of aromatic radicals and
produced by the novel process preferably have densities of from
2i6106~
20 to 50 g/1 and usually have a thermal conductivity of less
than 0.020 W/m=K, for example from 0.020 to 0.017 W/ni=K or
less.
The rigid PU foams are preferably used as heat-insulating
interlayers in composite elements and for foam-filling cavities
in housings for refrigeration equipment, in particular for
refrigerators and freezers, and as the jacket of hot-water
storage tanks. The products are also suitable for the
10 insulation of warmed materials, as engine covers and as pipe
shells.
Examples
Production of rigid PU foams
Comparative Example I
Component A: a mixture comprising
63.5 parts by weight of a polyether-polyol having a hydroxyl
number of 440, prepared by ariionic polyaddition of
1,2-propylene oxide onto sucrose,
15.0 parts by weight of a polyether-polyol having a hydroxyl
number of 400, prepared by anionic polyaddition of
1,2-propylene oxide onto sorbitol,
10.0 parts by weight of a polyether-polyol having a hydroxyl
number of 120, prepared by anionic polyaddition of
1,2-propylene oxide onto
N-(3-dimethylaminopropyl)ethylenediaminE_, followed by
anionic polyaddition of ethylene oxide onto the resultant
N-(3-dimethy.laminopropyl)ethylenediaminE=_/1,2-propylene
oxide adduct,
5.0 parts by weight of polyoxypropylene glycol having a
hydroxyl number of 250,
1.5 parts by weight of a silicone-based foarn stabilizer
(Tegostab'vt' B 8462 from Goldschmi_dt AG, Essen),
2.2 parts by weight of N,N-dimethylcyclohexylamine,
0.5 part by weight of a 47% strength by weiqht solution of
potassium acetat:e in ethylene glycol,
2.0 parts by weight of water and
11.0 parts by weight of cyclopentarie.
216 106 5
21
Component B:
A mixture of diphenylmethane diisocyanat.es and
polyphenyl-polymethylerie polyisocyanates (crude MDI) having an
NCO content of 31.5% by weight and a content of aromatic
radicals of about 56% by weight.
100 parts by weight of component A and
125 parts by weight of component B were mixed in a
high-pressure Puromat'j~ PU 15 unit, and the reaction
mixture was injected into a Bosch lance., A uniform rigid
PU foam having a density of about 38 g/]L and a thermal
conductivity of 20.5 mW/mK, measured at 23 C, was
obtained. The content of aromatic radicals in the
formative comporrents (a) to (c) was 31% by weight.
Example 1
Component A: a mixture comprising
63.5 parts by weight of a polyether-polyo]. having a hydroxyl
number of 440, prepared by anionic polyaddition of
1,2-propylene oxide onto sucrose,
15.0 parts by weight of a polyether-polyol having a hydroxyl
number of 550 and a content of aromatic radicals of about
11% by weight, prepared by ariionic polyaddition of
1,2-propylene oxide onto, as initiator molecule, a
Mannich condensate obtai.nable from
4,4'-dihydroxy-2,2-diphenylpropane, forrnaldehyde and
diethanolamine,
10.0 parts by weight of a polyether-polyol having a hydroxyl
number of 120, prepared by anionic polyaddition of
1,2-propylene oxide onto
N-(3-dimethylaminopropyl)ethylenediamine, followed by
anionic polyaddition of ethylene oxide onto the resultant
N-(3-dimethylaminopropyl.)ethylenediamine/1,2-propylene
oxide adduct,
5.0 parts by weight of polyoxypropylene glycol having a
hydroxyl number of 250,
1.5 parts by weight of a silicone-based foarn stabilizer
(Tegostab'J~ B 8462 from Goldschmidt. AG, Essen),
2.2 parts by weight of N,N-dimethylcyclohexylamine,
0.5 part by weight of a 47% strength by weight solution of
potassium acetate in ethylene glycol,
2161065
22
2.0 parts by weight of water and
11.0 parts by weight of cyclopentane.
Component B:
A mixture of diphenylmethane diisocyanates and
polyphenyl-polymethylene polyisocyanates (crudle MDI) having an
NCO content of 31.5% by weight and a conterit of aromatic
radicals of about 56% by weight.
100 parts by weight of component A and
130 parts by weight of component. B were mixed in a
high-pressure Puromat'"' PU 15 unit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 38 g/l and a thermal
conductivity of 19.7 mW/mK, measured at 230C, was
obtained. The content of aromatic radicals in the
formative comporients (a) to (c) was 32.4% by weight.
Example 2
Component A: a mixture comprising
48.5 parts by weight of a polyether-pol.yol having a hydroxyl
number of 440, prepared by anioriic polyaddition of
1,2-propylene oxide onto sucrose,
30.0 parts by weight of a polyether-pol.yol having a hydroxyl
number of 550 and a content of aromatic radicals of about
11% by weight, prepared by anionic polyaddition of
1,2-propylene oxide onto, as initiator rnolecule, a
Mannich condensate obtainable from
4,4'-dihydroxy-?,2-diphenylpropane, formaldehyde and
diethano.lamine,
10.0 parts by weight of a polyether-polyol having a hydroxyl
number of 120, prepared by anionic polyaddition of
1,2-propylene oxide onto
N-(3-dimethylam:inopropyl)ethylenediamine, followed by
anionic polyaddition of ethylene oxide onto the resultant
N-(3-dimethylam:inopropyl)ethylenediamine/1,2-propylene
oxide adduct,
5.0 parts by weight of polyoxypropylene glycol having a
hydroxyl number of 250,
1.5 parts by weight of a silicone-based foam stabilizer
(Tegostab"~' B 8462 from Goldschmidt AG, Essen),
2161065
23
2.2 parts by weight of N,N-dimethylcyclohexylamine,
0.5 part by weight of a 47% str_ength by weight solution of
potassium acetate in ethylene glycol,
2.0 parts by weight of water and
11.0 parts by weight of cyclopentane.
Component B: analogou=_: to Example 1.
100 parts by weight of component A and
133 parts by weight of component B were mixed in a
high-pressure Puromat.o PLI 15 uriit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 38.7 g/1 and a thermal
conductivity of 19.0 mW/mK, measured at 23 C, was
obtained. The content of aromatic radicals in the
formative components (a) to (c) was 33.4% by weight.
Example 3
Component A: a mixture comprising
55.9 parts by weight of a polyether-polyol having a hydroxyl
number of 370 and a content of aromatic radicals of 19.3%
by weight, prepared by anionic polycondensation of
1,2-propylene oxide onto a mixture of
diaminodiphenylinethane isomers and
polyphenyl-po.lymethylene-polyamines,
37.0 parts by weight of a polyether-polyol having a hydroxyl
number of 340, prepared by anionic: polyaddition of
1,2-propylene oxide onto sorbitol,
3.0 parts by weight of a silicone-based foain stabilizer
(Tegostab'"' B 8465 from Goldschmidt AG, Essen),
1.3 parts by weight of N,N-dimethyl.cyclohexylamine,
0.7 part by weight of N, N, N' , N" , N"---pentamethyl-
diethylenetriamine,
0.3 part by weight of dipotassium hydrogenplhosphate,
1.8 parts by weight of water and
13.0 parts by weight of cyclopentane.
'2i b1,065
24
Component B: analogous to Example 1.
100 parts by weight of component A and
110 parts by weight of component B were mixed in a
high-pressure Puromat'~ PU 1.5 uriit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about :36 g/l and a thermal
conductivity of 20.0 mW/mK, measured at 23 C, was
obtained. The content of aromatic radicals in the
formative components (a) to (c) was 34.5% by weight.
Example 4
Component A: analogous to Example 3.
Component B: analogous to Example 1.
100 parts by weight of component A and
130 parts by weight of component B were mixed in a
high-pressure Puromat(R) PU 15 unit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 38 g/l and a thermal
conductivity of 19.2 mW/mK, measured at 23 C, was
obtained. The content of aromatic radicals in the
formative components (a) to (c) was 36.5% by weight.
Example 5
Component A: a mixture comprising
30.0 parts by weight of a polyether-polyol having a hydroxyl
number of 350 and a content of aromatic radicals of 11.4%
by weight, prepared by block copolyaddition of
1,2-propylene oxide (50% by weight) and ethylene oxide
(50% by weight) onto a tolylenediamine isomer mixture as
initiator molecules,
23.7 parts by weight of a polyether-polyol having a hydroxyl
number of 440, prepared by anionic polyaddition of
1,2-propylene oxide onto sucrose,
20.0 parts by weight of a polyether-polyol having a hydroxyl
number of 550 and a content of aromatic radicals of about
11% by weight, prepared by anionic polyaddition of
1,2-propylene oxide onto, as initiator molecule, a
2161665
Mannich condensate obtainable from
4,4'-dihydroxy-2,2--diphernylpropane, formaldehyde and
diethanolamine,
20.0 parts by weight of a polyether-po].yol having a hydroxyl
number of 120, prepared by anionic polyadditio:n of
1,2-propylene oxide onto
N-(3-dimethylam:inopropyl)ethylenediamine, followed by
anionic polyadd_ltion of ethylene oxide onto the resultant
N-(3-dimethylaminopropyl)ethylenediamine/1,2-propylene
10 oxide adduct,
3.0 parts by weight of a silicone-based foam stabilizer
(Tegostab B 8465 from Goldschmicit AG, Essen),
1.0 parts by weight of N,N-dimethylcyclohexylamine,
0.5 part by weight of
N,N,N',N ",N " -pentamethyldiethylenetriamine,
1.8 parts by weight of water and
13.0 parts by weight of cyclopentane.
Component B: analogous to Example 1.
100 parts by weight of component A and
123 parts by weight of component B were mixed in a
high-pressure Puromat''V PU 15 unit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 35 g/1 and a thermal
conductivity of 19.5 mW/mK, measured at 23 C, was
obtained. The content of aromatic radicals in the
formative comporients (a) to (c) was 33.4% by weight.
Example 6
Component A: analogous to Example 5
Component B: analogous to Example 1.
100 parts by weight of component A and
145 parts by weight of component B were mixed in a
high-pressure Ptzromat'a' PU 15 unit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 37 g/l and a thermal
conductivity of 18.8 mW/mK, measured at 23 C, was
obtained. The content of aromatic radicals in the
formative components (a) to (c) was 35.4% by weight.
216 1 fi5
26
Example 7
Component A: a mixture comprising
20.0 parts by weight of a polyester-polyol having a hydroxyl
number of 240 and a content of aromatic radicals of about
25% by weight, prepared by polycondensation of phthalic
anhydride, ethylene glycol and diethylene glycol in a
weight ratio of 43:5:52,
43.6 parts by weight of a polyether-polyol having a hydroxyl
number of 490, prepared by anionic polyaddition of
1,2-propylene oxide onto sucrose,
20.0 parts by weight of a polyether-polyol having a hydroxyl
number of 570 and a content of aromatic radicals of about
11.4% by weight, prepared by anionic polyaddition of
1,2-propylene oxide onto, as initiator rnolecule, a
Mannich condensate obtainable froni
4,4'-dihydroxy-2,2-diphenyl.pr.opane, forrnaldehyde and
diethanolamine,
10.0 parts by weight of a polyether-polyol having a hydroxyl
number of 770, prepared by anionic polyaddition of
1,2-propylene oxide onto ethylenediamine as initiator
molecule,
2.5 parts by weight of a silicone-based foarn stabilizer
(Tegostab0 B 8465 from Goldschmi(it AG, Essen),
1.4 parts by weight of N,N-dimethylcyclohexyl.amine,
0.7 part by weight of 2,2'-bis(dimethylamino)diethyl ether,
1.8 parts by weight of water and
13.0 parts by weight of cyclopentane.
Component B: analogous to Example 1.
100 parts by weight of component A and
130 parts by weight of component B were mixed in a
high-pressure Puromat(1' PU 15 unit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 37 g/l and a thermal
conductivity of 18.9 mW%mK, measured at 23 C, was
obtained. The content of aromatic radicals in the
formative comporients (a) to (c) was 34.8% by weight.
276 'i~6 5
27
Comparative Example II
Component A: a mixture comprising
43.15 parts by weight of a polyether-polyol having a hydroxyl
number of 440, prepared by ariionic polyaddition of
1,2-propylene oxide onto sucrose,
20.0 parts by weight of a polyether-polyol having a hydroxyl
number of 490, prepared by anionic polyaddition of
1,2-propylene oxide onto sucrose,
12.0 parts by weight of polyoxypropylene glycol having a
hydroxyl number of 105,
1.2 parts by weight of a silicone-based foarn stabilizer
(Tegostabo" B 8409 from Goldschmidt AG, Lssen),
0.9 part by weight of 1,6-bis(dimethylamino)hexane,
0.4 part by weight of
1,3,5-tris(3-dimethylaminopropyl)hexahydro-s-triazine,
0.4 part by weight of N,N-dimethylcyclohexylamine,
0.3 part by weight of a 75% strength by weight solution of
2,2'-bis(dimethylamino)diethyl ether in dipropylene
glycol,
1.65 parts by weight of water and
20.0 parts by weight of 1,1-dichloro-l--fluoroethane (Rl4lb).
Component B: analogous to Example 1
100 parts by weight of component A and
116 parts by weight of component B were mixed in a
high-pressure Puromat'A) PU 15 unit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 38 g/l and a thermal
conductivity of 19 mW/mK, measured at 2:3 C, was obtained.
The content of aromatic radicals in the formative
comporients (a) to (c) was 30.096 by weight.
Example 8
Component A: a mixture comprising
30.0 parts by weight of a polyether-pol.yol having a hydroxyl
number of 400 and a content of aromatic radicals of 13.4%
by weight, prepared by block copolyaddition of
216106 5
28
1,2-propylene oxide (70% by weight) and ethylene oxide
(30% by weight) onto a tolylenediamine isomer mixture as
initiator molecules,
22.5 parts by weight of a polyether--polyol having a hydroxyl
number of 490, prepared by ariionic polyaddition of
1,2-propylene oxide onto sucrose,
20.0 parts by weight of a polyether-polyol having a hydroxyl
number of 550 and a content of aromatic radicals of about
11% by weight, prepared by ariionic polyaddition of
1,2-propylene oxide onto, as initiator molecule, a
Mannich condensate obtainable from
4,4'-dihydroxy-2,2--diphenylpropane, formaldehyde and
diethanolamine,
15.0 parts by weight of a polyether-polyol having a hydroxyl
number of 120, prepared by ariionic polyaddition of
1,2-propylene oxide onto
N-(3-dimethylaminopropyl)ethylenedi.amine, followed by
anionic polyaddition of ethylene oxide onto the resultant
N-(3-dimethylami_nopropyl)ethylenediamine/1,2-p:ropylene
oxide adduct,
5.0 parts by weight of polyoxypropylene glyc:ol having a
hydroxyl number of 250,
3.0 parts by weight of a silicone-based foam stabilizer
(Tegostab B 8465 Goldschmidt AG, Essen),
0.7 part by weight of
N,N,N',N ",N " -pentamethyldiethylenetriamine,
0.5 part by weight of N,N-dimethylcyclohexy]Lamine,
0.5 part by weight of a 42% strength by weiqht solution of a
salt of a trimet.hylamine/1,2-propylene oxide adduct and
formic acid in clipropylene glycol,
2.5 parts by weight of water and
20.0 parts by weight of 1,1-dichloro-l--fluoroethane (R141b).
Component B: analogous to Example 1.
100 parts by weight of component A and
140 parts by weight of component B were mixed in a
high-pressure Puromat(N' PU 15 unit, and the reaction
mixture was injected into a Bosch lance. A uniform rigid
PU foam having a density of about 38 g/1 and a thermal
conductivity of 17.5 mW/mK, measured at 23'C, was
obtained. The content of aromatic radicals in the
formative components (a) to (c) was 34.8% by weight.
