Note: Descriptions are shown in the official language in which they were submitted.
CA 02862774 2014-06-30
. a
1
Producing rigid polyurethane foams and rigid polyisocyanu rate foams
Description
The present invention relates to a process for producing rigid polyurethane
foams or rigid polyiso-
cyanurate foams using certain polyetherester polyols based on aromatic
dicarboxylic acids. The
present invention also relates to the rigid foams thus obtainable and also to
their use for producing
sandwich elements having rigid or flexible outer layers. The present invention
further relates to the
underlying polyol components.
The production of rigid polyurethane foams by reacting organic or modified
organic di- or polyisocy-
anates with comparatively high molecular weight compounds having two or more
than two reactive
hydrogen atoms, especially with polyether polyols from alkylene oxide
polymerization or polyester
polyols from the polycondensation of alcohols with dicarboxylic acids in the
presence of polyure-
thane catalysts, chain-extending and/or crosslinking agents, blowing agents
and further auxiliary
and admixture agents is known and has been described in numerous patent and
literature publica-
tions.
In the context of the present disclosure, the terms "polyester polyol",
"polyesterol", "polyester alco-
hol" and the abbreviation "PESOL" are used interchangeably.
Customary polyester polyols are polycondensates of aromatic and/or aliphatic
dicarboxylic acids
and alkanediols and/or ¨trials, or ether diols. However it is also possible to
process polyester scrap,
especially polyethylene terephthalate (PET) and/or polybutylene terephthalate
(PBT) scrap. A
whole series of processes are known and have been described for this purpose.
Some processes
are based on converting the polyester into a diester of terephthalic acid, for
example dimethyl ter-
ephthalate. DE-A 100 37 14 and US-A 5,051,528 describe such
transesterifications using methanol
and transesterification catalysts.
It is also known that esters based on terephthalic acid are superior to esters
based on phthalic acid
in terms of burning behavior, as described in WO 2010/043624 for example.
When polyester polyols based on aromatic carboxylic acids or derivatives
thereof (such as tereph-
thalic acid or phthalic anhydride) are used to produce rigid polyurethane (PU)
foams, the high vis-
CA 02862774 2014-06-30
=
2
cosity of the polyester polyols often has a noticeably adverse effect, since
the viscosity of blends
with the polyesters rises as a result, which makes mixing with the isocyanate
distinctly more diffi-
cult.
EP-A 1 058 701 discloses aromatic polyester polyols of low viscosity, which
are obtained by trans-
esterifying a mixture of phthalic acid derivatives, diols, polyols and
hydrophobic fat-based materials.
In addition, certain systems for producing rigid PU foams, for example those
employing glycerol as
comparatively high-functionality alcoholic polyester component, can give rise
to problems due to
insufficient dimensional stability in that the foamed product distorts
significantly after demolding or
after the pressure section when processed by the double belt process.
Nor has the problem with the behavior of rigid PU foams in the event of fire
hitherto been satisfacto-
rily solved for all systems. For example, a toxic compound can form in the
event of fire when using
trimethylolpropane (TMP) as comparatively high-functionality alcoholic
polyester component.
A general problem with the production of rigid foams is the formation of
surface defects, preferen-
tially at the interface with metallic outer layers. These foam surface defects
cause formation of an
uneven metal surface in sandwich elements and thus often lead to visual
unacceptability of the
product. An improvement in the foam surface reduces the frequency with which
such surface de-
fects occur and thus leads to a visual improvement in the surface of sandwich
elements.
Rigid polyurethane foams frequently display high brittleness on cutting with
severe evolution of dust
and high sensitivity on the part of the foam, and also on sawing where
particularly the sawing of
composite elements with metallic outer layers and a core of polyisocyanurate
foam can lead to
crack formation in the foam.
It is further generally desirable to provide systems having a very high self-
reactivity in order that the
use of catalysts may be minimized.
It is an object of the invention to provide polyester polyols based on
aromatic dicarboxylic acids for
the production of rigid PU foams with low brittleness. A further object of the
invention is to provide a
polyol component which comprises the polyester polyols and has a high self-
reactivity.
CA 02862774 2014-06-30
3
Further objects, moreover, were to improve, or at least not to impair, the
dimensional tolerance of
the PU end products, and also to reduce, or at least not to worsen, the
formation of toxic com-
pounds in the event of fire. Moreover, an intention was to enhance the
processing properties in
relation to the development of surface defects.
Furthermore, an aim is for the polyester polyols to have a low viscosity, in
order to allow them to be
readily metered and mixed during the production of the rigid PU foams. The
solubility of blowing
agents, such as of pentane, for example, in the polyol component ought also to
be extremely good.
This object is achieved by a process for producing rigid polyurethane foams or
rigid polyisocyanu-
rate foams comprising the reaction of
A) at least one polyisocyanate,
B) at least one polyetherester polyol obtainable by esterification of
b1) 10 to 70 mol% of a dicarboxylic acid composition comprising
b11) 50 to 100 mol%, based on the dicarboxylic acid composition, of one or
more aro-
matic dicarboxylic acids or derivatives thereof,
b12) 0 to 50 mol%, based on said dicarboxylic acid composition b1), of one or
more al-
iphatic dicarboxylic acids or derivatives thereof,
b2) 2 to 30 mol% of one or more fatty acids and/or fatty acid derivatives,
b3) 10 to 70 mol% of one or more aliphatic or cycloaliphatic diols having 2
to 18 carbon at-
oms or alkoxylates thereof,
b4) 2 to 50 mol% of a polyether polyol having a functionality of not less
than 2, prepared by
alkoxylating a polyol having a functionality of above 2,
all based on the total amount of components b1) to b4), wherein said
components b1) to b4)
sum to 100 mol%,
C) optionally further polyester polyols other than those of component
B),
D) at least one polyether polyol, and
E) optionally flame retardants,
F) one or more blowing agents,
G) catalysts, and
H) optionally further auxiliaries or admixture agents,
wherein the mass ratio of total components B) and optionally C) to component
D) is at least 7.
CA 02862774 2014-06-30
4
The present invention also provides a polyol component comprising the
aforementioned compo-
nents B) to H), wherein the mass ratio of total components B) and optionally
C) to component D) is
at least 7.
The present invention further provides rigid polyurethane and rigid
polyisocyanurate foams obtain-
able from the process of the present invention, and their use for producing
sandwich elements hav-
ing rigid or flexible outer layers.
The invention will now be more particularly described. Combinations of
preferred embodiments are
not outside the scope of the present invention. This applies particularly in
respect of those embodi-
ments of the individual components A) to H) of the present invention that are
characterized as pre-
ferred. The embodiments recited hereinbelow in the context of components B) to
H) relate not only
to the process of the present invention and the rigid foams thus obtainable
but also to the polyol
components of the present invention.
Component B
In the context of the present disclosure, the terms "polyester polyol" and
"polyesterol" are used in-
terchangeably as are the terms "polyether polyol" and "polyetherol".
Component b11) preferably comprises at least one compound selected from the
group consisting of
terephthalic acid, dimethyl terephthalate (DMT), polyethylene terephthalate
(PET), phthalic acid,
phthalic anhydride (PA) and isophthalic acid. It is particularly preferable
for component b11) to
comprise at least one compound from the group consisting of terephthalic acid,
dimethyl tereph-
thalate (DMT), polyethylene terephthalate (PET) and phthalic anhydride (PA).
It is very particularly
preferable for component b11) to comprise phthalic anhydride, dimethyl
terephthalate (DMT), ter-
ephthalic acid or mixtures thereof. The component b11) aromatic dicarboxylic
acids or derivatives
thereof are more preferably selected from the aforementioned aromatic
dicarboxylic acids and di-
carboxylic acid derivatives respectively and specifically from terephthalic
acid and/or dimethyl ter-
ephthalate (DMT). Terephthalic acid and/or DMT in component b11) leads to
polyether esters B)
having particularly good fire protection properties. Terephthalic acid is very
particularly preferable
since, in contrast to DMT, the formation of disruptive elimination products
can be avoided.
CA 02862774 2014-06-30
In general, aliphatic dicarboxylic acids or derivatives (component b12)) are
comprised in the dicar-
boxylic acid composition b1) at 0 to 30 mol%, preferably 0 to 10 mol%. It is
particularly preferable
for the dicarboxylic acid composition b1) to comprise no aliphatic
dicarboxylic acids or derivatives
thereof and thus to consist, to 100 mol%, of one or more aromatic dicarboxylic
acids or derivatives
5 thereof, the aforementioned being preferred.
The component b2) is preferably used in amounts of 3 to 20 mol%, more
preferably 5 to 18 mol%.
The component b3) is preferably used in amounts of 20 to 60 mol%, preferably
in the range from 25
to 55 mol%, more preferably in the range from 30 to 45 mol%.
The component b4) is preferably used in amounts of 2 to 40 mol%, preferably 8
to 35 mol%, more
preferably 15 to 25 mol%.
In one embodiment of the invention, the fatty acid or fatty acid derivative
b2) consists of a fatty acid
or fatty acid mixture, one or more glycerol esters of fatty acids or of fatty
acid mixtures, and/or one
or more fatty acid monoesters, for example biodiesel or methyl esters of fatty
acids, and it is par-
ticularly preferable for component b2) to consist of a fatty acid or fatty
acid mixture and/or one or
more fatty acid monoesters; more specifically component b2) consists of a
fatty acid or fatty acid
.. mixture and/or biodiesel, and component b2) specifically consists of a
fatty acid or fatty acid mix-
ture.
In one preferred embodiment of the invention, the fatty acid or fatty acid
derivative b2) is selected
from the group consisting of castor oil, polyhydroxy fatty acids, ricinoleic
acid, hydroxyl-modified
oils, grapeseed oil, black cumin oil, pumpkin kernel oil, borage seed oil,
soybean oil, wheat germ
oil, rapeseed oil, sunflower seed oil, peanut oil, apricot kernel oil,
pistachio oil, almond oil, olive oil,
macadamia nut oil, avocado oil, sea buckthorn oil, sesame oil, hemp oil,
hazelnut oil, primula oil,
wild rose oil, safflower oil, walnut oil, animal tallow, for example beef
dripping, fatty acids, hydroxyl-
modified fatty acids, biodiesel, methyl esters of fatty acids and fatty acid
esters based on
myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid, petroselic
acid, gadoleic acid, erucic
acid, nervonic acid, linoleic acid, a- and y-linolenic acid, stearidonic acid,
arachidonic acid, tim-
nodonic acid, clupanodonic acid and cervonic acid, and mixed fatty acids.
In a particularly preferred embodiment of the present invention, the fatty
acid or fatty acid derivative
CA 02862774 2014-06-30
6
b2) is oleic acid, biodiesel, soybean oil, rapeseed oil or tallow,
particularly preferably oleic acid,
biodiesel, soybean oil, rapeseed oil or beef dripping, more specifically oleic
acid or biodiesel and
most specifically oleic acid. The fatty acid or the fatty acid derivative
improves, inter alia, the blow-
ing agent solubility in the production of rigid polyurethane foams.
It is very particularly preferable for component b2) not to comprise any
triglyceride, especially no oil
or fat. The glycerol released from the triglyceride by
esterification/transesterification has an adverse
effect on the dimensional stability of the rigid foam, as mentioned above.
Preferred fatty acids and
fatty acid derivatives in the context of component b2) are therefore the fatty
acids themselves and
also alkyl monoesters of fatty acids or alkyl monoesters of fatty acid
mixtures, especially the fatty
acids themselves and/or biodiesel.
Preferably, the aliphatic or cycloaliphatic diol b3) is selected from the
group consisting of ethylene
glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol,
1,5-pentanediol,
1,6-hexanediol, 2-methyl-1,3-propanediol and 3-methyl-1,5-pentanediol and
alkoxylates thereof. It
is particularly preferable for the aliphatic dial b3) to be monoethylene
glycol or diethylene glycol,
especially diethylene glycol.
Component b4) can in particular be prepared using potassium hydroxide or an
amine as catalyst.
However, the use of KOH requires an additional work-up step. In one preferred
embodiment of the
present invention, the amine catalyst for preparing component b4) is selected
from the group com-
prising dimethylethanolamine (DMEOA), imidazole and imidazole derivatives and
also mixtures
thereof, more preferably imidazole.
Preferably, such a polyether polyol b4) having a functionality above 2 is
used, which was prepared
by alkoxylating a polyol having a functionality of not less than 3.
According to the invention, the polyether polyol b4) has a functionality
greater than 2. It preferably
has a functionality of not less than 2.7 and especially of not less than 2.9.
In general, it has a func-
tionality of not more than 6, preferably not more than 5 and more preferably
not more than 4.
The polyether polyol b4) is preferably selected from the group consisting of
the reaction products of
sorbitol, polyglycerol, glycerol, trimethylolpropane (IMP), pentaerythritol or
mixtures thereof with an
alkylene oxide.
CA 02862774 2014-06-30
7
In one embodiment of the present invention, the polyether polyol b4) is
obtainable by reacting a
polyol having a functionality of greater than 2 with ethylene oxide and/or
propylene oxide, prefera-
bly with ethylene oxide. It is particularly preferable for the polyether
polyol b4) to be obtainable by
alkoxylation with ethylene oxide, leading to rigid polyurethane foams having
improved fire protec-
tion properties.
Preferably, the polyether polyol b4) is obtainable by alkoxylating, preferably
ethoxylating, a polyol
selected from the group consisting of sorbitol, pentaerythritol,
trimethylolpropane, glycerol, poly-
glycerol and mixtures thereof, and more preferably a polyol selected from the
group consisting of
trimethylolpropane and glycerol.
In a specific embodiment of the invention, the polyether polyol b4) consists
of the reaction product
of glycerol with ethylene oxide and/or propylene oxide, preferably with
ethylene oxide. This results
in a particularly high storage stability for component B.
In a further specific embodiment of the invention, the polyether polyol b4)
consists of the reaction
product of trimethylolpropane with ethylene oxide and/or propylene oxide,
preferably with ethylene
oxide. This likewise results in a particularly high storage stability for
component B).
Preferably, the polyether polyol b4) has an OH number in the range from 150 to
1250 mg KOH/g,
preferably from 300 to 950 mg KOH/g, particularly preferably from 500 to 800
mg KOH/g. In this
range, particularly favorable mechanical properties and also fire protection
properties are obtaina-
ble.
Preferably, at least 200 mmol, more preferably at least 400 mmol, even more
preferably at least
600 mmol, yet even more preferably at least 800 mmol and yet still even more
preferably at least
1000 mmol of component b4) are used per kg of polyetherester polyol B).
In a particularly preferred embodiment of the invention, the polyether polyol
b4) consists of the re-
action product of trimethylolpropane or glycerol, preferably glycerol, with
ethylene oxide, wherein
the OH number of polyether polyol b4) is in the range from 500 to 800 mg KOH/g
and preferably
from 500 to 650 mg KOH/g.
CA 02862774 2014-06-30
8
In an especially preferred embodiment of the invention, the polyether polyol
b4) consists of the re-
action product of trimethylolpropane or glycerol, preferably glycerol, with
ethylene oxide, wherein
the OH number of polyether polyol b4) is in the range from 500 to 800 mg KOH/g
and preferably
from 500 to 650 mg KOH/g, the aliphatic or cycloaliphatic diol b3) is
diethylene glycol, and the fatty
acid or fatty acid derivative b2) is oleic acid.
The number-weighted average functionality of polyetherester polyol B) is
preferably not less than 2,
more preferably greater than 2, even more preferably greater than 2.2 and
especially greater than
2.3, which leads to a higher crosslink density on the part of the polyurethane
produced therewith
and hence to better mechanical properties on the part of the polyurethane
foam.
To prepare the polyetherester polyols, the aliphatic and aromatic
polycarboxylic acids and/or deriv-
atives and polyhydric alcohols can be polycondensed in the absence of
catalysts or preferably in
the presence of esterification catalysts, advantageously in an atmosphere of
inert gas, e.g. nitro-
gen, in the melt at temperatures of from 150 to 280 C, preferably from 180 to
260 C, optionally un-
der reduced pressure, to the desired acid number which is advantageously less
than 10, preferably
less than 2. In a preferred embodiment, the esterification mixture is
polycondensed at the above-
mentioned temperatures to an acid number of from 80 to 20, preferably from 40
to 20, under at-
mospheric pressure and subsequently under a pressure of less than 500 mbar,
preferably from 40
to 400 mbar. Possible esterification catalysts are, for example, iron,
cadmium, cobalt, lead, zinc,
antimony, magnesium, titanium and tin catalysts in the form of metals, metal
oxides or metal salts.
However, the polycondensation can also be carried out in the liquid phase in
the presence of dilu-
ents and/or entrainers such as, e.g., benzene, toluene, xylene or
chlorobenzene in order to distill off
the water of condensation as an azeotrope.
To prepare the polyetherester polyols, the organic polycarboxylic acids and/or
derivatives and poly-
hydric alcohols are advantageously polycondensed in a molar ratio of 1:1-2.2,
preferably 1:1.05-2.1
and particularly preferably 1:1.1-2Ø
The polyetherester polyols obtained generally have a number-average molecular
weight in the
range from 300 to 3000, preferably in the range from 400 to 1000 and
especially in the range from
450 to 800.
The proportion of polyetherester polyols B) according to the present invention
is generally at least
CA 02862774 2014-06-30
9
wt%, preferably at least 20 wt%, more preferably at least 40 wt% and even more
preferably at
least 50 wt%, based on total components B) to H).
To produce the rigid polyurethane foams by the process of the invention, use
is made of, in addition
5 .. to the above-described specific polyester polyols (polyetherester polyols
B), the constructional
components which are known per se, about which the following details may be
provided.
Component A
10 .. A polyisocyanate for the purposes of the present invention is an organic
compound comprising two
or more than two reactive isocyanate groups per molecule, i.e., the
functionality is not less than 2.
When the polyisocyanates used or a mixture of two or more polyisocyanates do
not have a unitary
functionality, the number-weighted average functionality of component A) used
will be not less than
2.
Useful polyisocyanates A) include the aliphatic, cycloaliphatic, araliphatic
and preferably aromatic
polyfunctional isocyanates which are known per se. Polyfunctional isocyanates
of this type are
known per se or are obtainable by methods known per se. Polyfunctional
isocyanates can more
particularly also be used as mixtures, in which case component A) comprises
various polyfunctional
.. isocyanates. The number of isocyanate groups per molecule in polyfunctional
isocyanates useful as
polyisocyanate is two (and so the polyfunctional isocyanates in question are
referred to hereinbe-
low as diisocyanates) or more than two.
Particularly the following may be mentioned in detail: alkylene diisocyanates
having 4 to 12 carbon
.. atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-
ethyltetramethylene 1,4-
diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, tetramethylene 1,4-
diisocyanate, and
preferably hexamethylene 1,6-diisocyanate; cycloaliphatic diisocyanates such
as cyclohexane 1,3-
and 1,4-diisocyanate and also any desired mixtures of these isomers, 1-
isocyanato-3,3,5-trimethy1-
5-isocyanatomethylcyclohexane (IPDI), 2,4- and 2,6-hexahydrotolylene
diisocyanate and also the
.. corresponding isomeric mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane
diisocyanate and also
the corresponding isomeric mixtures, and preferably aromatic polyisocyanates,
such as 2,4- and
2,6-tolylene diisocyanate and the corresponding isomeric mixtures, 4,4'-, 2,4'-
and 2,2'-
diphenylmethane diisocyanate and the corresponding isomeric mixtures, mixtures
of 4,4'- and 2,2'-
diphenylmethane diisocyanates, polyphenylpolymethylene polyisocyanates,
mixtures of 4,4'-, 2,4'-
CA 02862774 2014-06-30
and 2,2'-diphenylmethane diisocyanates and polyphenylpolymethylene
polyisocyanates (crude
MDI) and mixtures of crude MDI and tolylene diisocyanates.
Of particular suitability are 2,2'-, 2,4'- and/or 4,4'-diphenylmethane
diisocyanate (MDI),
5 1,5-naphthylene diisocyanate (ND1), 2,4- and/or 2,6-tolylene diisocyanate
(TDI), 3,3'-dimethyl-
biphenyl diisocyanate, 1,2-diphenylethane diisocyanate and/or p-phenylene
diisocyanate (PPDI),
tri-, tetra-, penta-, hexa-, hepta- and/or octamethylene diisocyanate, 2-
methylpentamethylene 1,5-
diisocyanate, 2-ethylbutylene 1,4-diisocyanate, pentamethylene 1,5-
diisocyanate, butylene 1,4-
diisocyanate, 1-isocyanato-3,3,5-trimethy1-5-isocyanatomethylcyclohexane
(isophorone diisocya-
10 nate, 1PDI), 1,4- and/or 1,3-bis(isocyanatomethyl)cyclohexane (HXDI),
1,4-cyclohexane diisocya-
nate, 1-methyl-2,4- and/or -2,6-cyclohexane diisocyanate and 4,4'-, 2,4'-
and/or 2,2'-
dicyclohexylmethane diisocyanate.
Frequent use is also made of modified polyisocyanates, i.e. products obtained
by chemical conver-
sion of organic polyisocyanates and having two or more than two reactive
isocyanate groups per
molecule. Polyisocyanates comprising ester, urea, biuret, allophanate,
carbodiimide, isocyanurate,
uretdione, carbamate and/or urethane groups may be mentioned in particular.
The following embodiments are particularly preferable as polyisocyanates of
component A):
i) polyfunctional isocyanates based on tolylene diisocyanate (TDI),
especially 2,4-TDI or
2,6-TDI or mixtures of 2,4- and 2,6-TDI;
ii) polyfunctional isocyanates based on diphenylmethane diisocyanate (MDI),
especially
2,2'-MDI or 2,4'-MDI or 4,4'-MDI or oligomeric MDI, which is also known as
polyphenyl-
polymethylene isocyanate, or mixtures of two or three aforementioned
diphenylmethane
diisocyanates, or crude MDI, which is obtained in the production of MDI, or
mixtures of at
least one oligomer of MDI and at least one aforementioned low molecular weight
MDI deriva-
tive;
iii) mixtures of at least one aromatic isocyanate as per embodiment i) and
at least one aromatic
isocyanate as per embodiment ii).
Polymeric diphenylmethane diisocyanate is very particularly preferred as
polyisocyanate. Polymeric
diphenylmethane diisocyanate (called polymeric MDI hereinbelow) is a mixture
of binuclear MDI
and oligomeric condensation products and thus derivatives of diphenylmethane
diisocyanate (MDI).
CA 02862774 2014-06-30
11
Polyisocyanates may preferably also be constructed from mixtures of monomeric
aromatic diisocy-
anates and polymeric MDI.
Polymeric MDI, in addition to binuclear MDI, comprises one or more polynuclear
condensation
products of MDI with a functionality of more than 2, especially 3 or 4 or 5.
Polymeric MDI is known
and often referred to as polyphenylpolymethylene isocyanate or else as
oligomeric MDI. Polymeric
MDI is typically constructed from a mixture of MDI-based isocyanates of
differing functionality. Pol-
ymeric MDI is typically used in admixture with monomeric MDI.
The (average) functionality of a polyisocyanate comprising polymeric MDI can
vary in the range
from about 2.2 to about 5, especially from 2.3 to 4, especially from 2.4 to
3.5. Crude MDI, obtained
as an intermediate in the production of MDI, is more particularly such a
mixture of MDI-based poly-
functional isocyanates having different functionalities.
Polyfunctional isocyanates or mixtures of two or more polyfunctional
isocyanates based on MDI are
known and available for example from BASF Polyurethanes GmbH under the name of
LupranatO.
The functionality of component A) is preferably at least two, especially at
least 2.2 and more prefer-
ably at least 2.4. The functionality of component A) is preferably from 2.2 to
4 and more preferably
from 2.4 to 3.
The isocyanate group content of component A) is preferably from 5 to 10
mmollg, especially from 6
to 9 mmol/g and more preferably from 7 to 8.5 mmol/g. A person skilled in the
art is aware of a re-
ciprocal relationship between the isocyanate group content in mmol/g and the
so-called equiva-
lence weight in g/equivalent. The isocyanate group content in mmol/g is
obtained from the content
in wt% according to ASTM D-5155-96 A.
In a particularly preferred embodiment, component A) consists of at least one
polyfunctional
isocyanate selected from diphenylmethane 4,4'-diisocyanate, diphenylmethane
2,4'-diisocyanate,
diphenylmethane 2,2'-diisocyanate and oligomeric diphenylmethane diisocyanate.
In this preferred
embodiment, component (al) more preferably comprises oligomeric
diphenylmethane diisocyanate
and has a functionality of at least 2.4.
The viscosity of component A) used can vary within wide limits. The viscosity
of component A) is
CA 02862774 2014-06-30
12
preferably in the range from 100 to 3000 mPa.s and more preferably in the
range from 200 to
2500 mPa.s.
Component C
Suitable polyester polyols C) differ from polyetherester polyols B) and can be
prepared, for exam-
ple, from organic dicarboxylic acids having 2 to 12 carbon atoms, preferably
aromatic ones, or mix-
tures of aromatic and aliphatic dicarboxylic acids, and polyhydric alcohols,
preferably diols, having
2 to 12 carbon atoms and preferably 2 to 6 carbon atoms.
Possible dicarboxylic acids are, in particular: succinic acid, glutaric acid,
adipic acid, suberic acid,
azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric
acid, phthalic acid,
isophthalic acid and terephthalic acid. It is likewise possible to use
derivatives of these dicarboxylic
acids, such as dimethyl terephthalate, for example. The dicarboxylic acids can
be used either indi-
vidually or in admixture with one another. It is also possible to use the
corresponding dicarboxylic
acid derivatives, e.g. dicarboxylic esters of alcohols having from 1 to 4
carbon atoms or dicarboxylic
anhydrides, in place of the free dicarboxylic acids. As aromatic dicarboxylic
acids, preference is
given to using phthalic acid, phthalic anhydride, terephthalic acid and/or
isophthalic acid as a mix-
ture or alone. As aliphatic dicarboxylic acids, preference is given to using
dicarboxylic acid mixtures
of succinic, glutaric and adipic acid in weight ratios of, for example, 20-35:
35-50: 20-32 parts by
weight and in particular adipic acid. Examples of dihydric and polyhydric
alcohols, in particular di-
ols, are: ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene
glycol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerol, trimethylolpropane
and pentaerythritol.
Preference is given to using ethanediol, diethylene glycol, 1,4-butanediol,
1,5-pentanediol, 1,6-
hexanediol or mixtures of at least two of the diols mentioned, in particular
mixtures of 1,4-
butanediol, 1,5-pentanediol and 1,6-hexanediol. It is also possible to use
polyester polyols derived
from lactones, e.g., c-caprolactone, or hydroxycarboxylic acids, e.g., co-
hydroxycaproic acid.
To prepare the further polyester polyols C), biobased starting materials
and/or derivatives thereof
are also suitable, for example castor oil, polyhydroxy fatty acids, ricinoleic
acid, hydroxyl-modified
oils, grapeseed oil, black cumin oil, pumpkin kernel oil, borage seed oil,
soybean oil, wheat germ
oil, rapeseed oil, sunflower seed oil, peanut oil, apricot kernel oil,
pistachio oil, almond oil, olive oil,
macadamia nut oil, avocado oil, sea buckthorn oil, sesame oil, hemp oil,
hazelnut oil, primula oil,
wild rose oil, safflower oil, walnut oil, fatty acids, hydroxyl-modified fatty
acids and fatty acid esters
CA 02862774 2014-06-30
13
based on myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid,
petroselic acid, gadoleic acid,
erucic acid, nervonic acid, linoleic acid, a- and y-linolenic acid,
stearidonic acid, arachidonic acid,
timnodonic acid, clupanodonic acid and cervonic acid.
The mass ratio of polyetherester polyols B) to polyester polyols C) is
generally at least 0.1, prefera-
bly at least 0.25, more preferably at least 0.5 and especially at least 0.8.
One especially preferred embodiment does not utilize any further polyester
polyols C).
Component D
One or more polyether polyols D) are used, according to the present invention,
as component D).
Polyetherols D) can be prepared by known methods, for example by anionic
polymerization of one
or more alkylene oxides having from 2 to 4 carbon atoms using alkali metal
hydroxides, e.g., sodi-
urn or potassium hydroxide, or alkali metal alkoxides, e.g., sodium methoxide,
sodium or potassium
ethoxide or potassium isopropoxide, or aminic alkoxylation catalysts, such as
dimethylethanolamine
(DMEOA), imidazole and/or imidazole derivatives, with use of at least one
starter molecule com-
prising from 2 to 8, preferably from 2 to 6, reactive hydrogen atoms in bonded
form, or by cationic
polymerization using Lewis acids, e.g., antimony pentachloride, boron fluoride
etherate, or bleach-
ing earth.
Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene
oxide, 1,2- or 2,3-
butylene oxide, styrene oxide and preferably ethylene oxide and 1,2-propylene
oxide. The alkylene
oxides can be used individually, alternately in succession or as mixtures.
Preferred alkylene oxides
are propylene oxide and ethylene oxide, with particular preference being given
to ethylene oxide.
Possible starter molecules are, for example: water, organic dicarboxylic
acids, such as succinic
acid, adipic acid, phthalic acid and terephthalic acid, aliphatic and
aromatic, optionally N-monoalkyl-
, N,N-dialkyl- and N,N'-dialkyl-substituted diamines having from 1 to 4 carbon
atoms in the alkyl
radical, e.g. optionally monoalkyl- and dialkyl-substituted ethylenediamine,
diethylenetriamine, tri-
ethylenetetramine, 1,3-propylenediamine, 1,3- or 1,4-butylenediamine, 1,2-,
1,3-, 1,4-, 1,5- and 1,6-
hexamethylenediamine, phenylenediamines, 2,3-, 2,4- and 2,6-tolylenediamine
and 4,4'-, 2,4'- and
2,2'-diaminodiphenylmethane. Particular preference is given to the recited
diprimary amines, for
example ethylenediamine.
CA 02862774 2014-06-30
14
Further possible starter molecules are: alkanolamines such as ethanolamine, N-
methyl-
ethanolamine and N-ethylethanolamine, dialkanolamines, such as diethanolamine,
N-methyl-
diethanolamine and N-ethyldiethanolamine and trialkanolamines, e.g.,
triethanolamine, and ammo-
nia.
Preference is given to using dihydric or polyhydric alcohols, e.g.,
ethanediol, 1,2- and 1,3-
propanediol, diethylene glycol (DEG), dipropylene glycol, 1,4-butanediol, 1,6-
hexanediol, glycerol,
trimethylolpropane, pentaerythritol, sorbitol and sucrose.
Polyether polyols D), preferably polyoxypropylene polyols and polyoxyethylene
polyols, more pref-
erably polyoxyethylene polyols, have a functionality of preferably 2 to 6,
more preferably 2 to 4,
especially 2 to 3 and specifically 2 and number-average molecular weights of
150 to 3000 g/mol,
preferably 200 to 2000 g/mol and especially 250 to 1000 g/mol.
One preferred embodiment of the invention utilizes an alkoxylated diol,
preferably an ethoxylated
dial, for example ethoxylated ethylene glycol, as polyether polyol D),
preferably polyethylene glycol
is concerned.
In a specific embodiment of the invention, the polyetherol component D)
consists exclusively of
.. polyethylene glycol, preferably with a number-average molecular weight of
250 to 1000 g/mol.
The proportion of polyether polyols D) is generally in the range from 0 to 11
wt%, preferably in the
range from 2 to 9 wt% and more preferably in the range from 4 to 8 wt%, based
on total cornpo-
nents B) to H).
The mass ratio of total components B) and C) to component D) in accordance
with the present in-
vention is greater than 7, preferably greater than 7.5, more preferably
greater than 8, even more
preferably greater than 10 and yet even more preferably greater than 12.
The mass ratio of total components B) and C) to component D) in accordance
with the present in-
vention is further less than 80, preferably less than 40, more preferably less
than 30, even more
preferably less than 20, yet even more preferably less than 16 and yet still
even more preferably
less than 14.
CA 02862774 2014-06-30
Component E
As flame retardants E), it is generally possible to use the flame retardants
known from the prior art.
Suitable flame retardants are, for example, brominated esters, brominated
ethers (Ixol) or bromin-
5 .. ated alcohols such as dibromoneopentyl alcohol, tribromoneopentyl alcohol
and PHT-4-diol and
also chlorinated phosphates such as tris(2-chloroethyl) phosphate, tris(2-
chloropropyl) phosphate
(TCPP), tris(1,3-dichloropropyl) phosphate, tricresyl phosphate, tris(2,3-
dibromopropyl) phosphate,
tetrakis(2-chloroethyl) ethylenediphosphate, dimethyl methanephosphonate,
diethyl diethanola-
minomethylphosphonate and also commercial halogen-comprising flame retardant
polyols. By way
10 of further phosphates or phosphonates it is possible to use diethyl
ethanephosphonate (DEEP),
triethyl phosphate (TEP), dimethyl propylphosphonate (DMPP) or diphenyl cresyl
phosphate (DPK)
as liquid flame retardants.
Apart from the abovementioned flame retardants, it is also possible to use
inorganic or organic
15 flame retardants such as red phosphorus, preparations comprising red
phosphorus, aluminum ox-
ide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and
calcium sulfate, ex-
pandable graphite or cyanuric acid derivatives such as melamine, or mixtures
of at least two flame
retardants, e.g. ammonium polyphosphates and melamine and optionally maize
starch or ammoni-
um polyphosphate, melamine, expandable graphite and optionally aromatic
polyesters for making
.. the rigid polyurethane foams flame resistant.
Preferable flame retardants have no isocyanate-reactive groups. The flame
retardants are prefera-
bly liquid at room temperature. Particular preference is given to TCPP, DEEP,
TEP, DMPP and
DPK.
The proportion of flame retardant E) is generally in the range from 2 to 50
wt%, preferably in the
range from 5 to 30 wt% and more preferably in the range from 8 to 25 wt%,
based on components
B) to H).
Component F
Blowing agents F) which are used for producing the rigid polyurethane foams
include preferably
water, formic acid and mixtures thereof. These react with isocyanate groups to
form carbon dioxide
and in the case of formic acid carbon dioxide and carbon monoxide. Since these
blowing agents
CA 02862774 2014-06-30
16
release the gas through a chemical reaction with the isocyanate groups, they
are termed chemical
blowing agents. In addition, physical blowing agents such as low-boiling
hydrocarbons can be used.
Suitable in particular are liquids which are inert towards the polyisocyanates
A) and have boiling
points below 100 C, preferably below 50 C, at atmospheric pressure, so that
they vaporize under
the conditions of the exothermic polyaddition reaction. Examples of such
liquids which can prefera-
bly be used are alkanes such as heptane, hexane, n-pentane and isopentane,
preferably industrial
mixtures of n-pentane and isopentane, n-butane and isobutane and propane,
cycloalkanes such as
cyclopentane and/or cyclohexane, ethers such as furan, dimethyl ether and
diethyl ether, ketones
such as acetone and methyl ethyl ketone, alkyl carboxylates such as methyl
formate, dimethyl oxa-
.. late and ethyl acetate and halogenated hydrocarbons such as methylene
chloride, dichloromono-
fluoromethane, difluoromethane, trifluoromethane, difluoroethane,
tetrafluoroethane, chlorodifluoro-
ethanes, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane and
heptafluoropropane.
Mixtures of these low-boiling liquids with one another and/or with other
substituted or unsubstituted
hydrocarbons can also be used. Organic carboxylic acids such as formic acid,
acetic acid, oxalic
acid, ricinoleic acid and carboxyl-containing compounds are also suitable.
It is preferable not to use any halogenated hydrocarbons as blowing agents. It
is preferable to use
water, formic acid-water mixtures or formic acid as chemical blowing agents
and formic acid-water
mixtures or formic acid are particularly preferred chemical blowing agents.
Pentane isomers or mix-
tures of pentane isomers are preferably used as physical blowing agents.
The chemical blowing agents can be used alone, i.e., without addition of
physical blowing agents,
or together with physical blowing agents. Preferably, the chemical blowing
agents are used togeth-
er with physical blowing agents, in which case the use of formic acid-water
mixtures or pure formic
acid together with pentane isomers or mixtures of pentane isomers is
preferred.
The blowing agents are either wholly or partly dissolved in the polyol
component (i.e.
B+Ci-D+E+F+G+H) or are introduced via a static mixer immediately before
foaming of the polyol
component. It is usual for water, formic acid-water mixtures or formic acid to
be fully or partially
.. dissolved in the polyol component and the physical blowing agent (for
example pentane) and any
remainder of the chemical blowing agent to be introduced "on-line".
The polyol component is admixed in situ with pentane, possibly some of the
chemical blowing
agent and also with all or some of the catalyst. Auxiliary and admixture
agents as well as flame
CA 02862774 2014-06-30
17
retardants are already comprised in the polyol blend.
The amount of blowing agent or blowing agent mixture used is in the range from
1 to 45 wt%, pref-
erably in the range from 1 to 30 wt% and more preferably in the range from 1.5
to 20 wt%, all based
on total components B) to H).
When water, formic acid or a formic acid-water mixture is used as blowing
agent, it is preferably
added to the polyol component (B+C+D+E+F+G+H) in an amount of 0.2 to 10 wt%,
based on com-
ponent 6). The addition of water, formic acid or formic acid-water mixture can
take place in combi-
nation with the use of other blowing agents described. Preference is given to
using formic acid or a
formic acid-water mixture in combination with pentane.
Component G
Catalysts G) used for preparing the rigid polyurethane foams are particularly
compounds which
substantially speed up the reaction of the components B) to H) compounds
comprising reactive
hydrogen atoms, especially hydroxyl groups, with the polyisocyanates A).
It is advantageous to use basic polyurethane catalysts, for example tertiary
amines such as tri-
ethylamine, tributylamine, dimethylbenzylamine, dicyclohexylmethylamine,
dimethylcyclo-
hexylamine, N,N,N',N'-tetramethyldiaminodiethyl ether,
bis(dimethylaminopropyl)urea,
N-methylmorpholine or N-ethylmorpholine, N-cyclohexylmorpholine, N,N,N',N'-
tetra-
methylethylenediamine, N,N,N,N-tetramethylbutanediamine, N,N,N,N-
tetramethylhexane-1,6-
diamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyI) ether,
dimethylpiperazine, N-
dimethylaminoethylpiperidine, 1,2-dimethylimidazole, 1-
azabicyclo[2.2.0]octane, 1,4-diaza-
bicyclo[2.2.2Joctane (Dabco) and alkanolamine compounds, such as
triethanolamine, triisopropano-
lamine, N-methyldiethanolamine and N-ethyldiethanolamine,
dimethylaminoethanol, 2-(N,N-
dimethylaminoethoxy)ethanol, N,N',N"-
tris(dialkylaminoalkyl)hexahydrotriazines, e.g. N,N',N"-
tris(dimethylaminopropy1)-s-hexahydrotriazine, and triethylenediamine.
However, metal salts such
as iron(II) chloride, zinc chloride, lead octoate and preferably tin salts
such as tin dioctoate, tin di-
ethylhexoate and dibutyltin dilaurate and also, in particular, mixtures of
tertiary amines and organic
tin salts are also suitable.
Further possible catalysts are: amidines such as 2,3-dimethy1-3,4,5,6-
tetrahydropyrimidine,
18
tetramethylammonium hydroxide, alkali metal hydroxides such as sodium
hydroxide and alkali met-
al alkoxides such as sodium methoxide and potassium isopropoxide, alkali metal
carboxylates and
also alkali metal salts of long-chain fatty acids having from 10 to 20 carbon
atoms and optionally
lateral OH groups. Preference is given to using from 0.001 to 10 parts by
weight of catalyst or cata-
lyst combination, based (i.e., reckoned) on 100 parts by weight of component
B). It is also possible
to allow the reactions to proceed without catalysis. In this case, the
catalytic activity of amine-
started polyols is exploited.
When, during foaming, a relatively large polyisocyanate excess is used,
further suitable catalysts
.. for the trimerization reaction of the excess NCO groups with one another
are: catalysts which form
isocyanurate groups, for example ammonium ion salts or alkali metal salts,
specifically ammonium
or alkali metal carboxylates, either alone or in combination with tertiary
amines. Isocyanurate for-
mation leads to flame-resistant PIR foams which are preferably used in
industrial rigid foam, for
example in building and construction as insulation boards or sandwich
elements.
Further information regarding the abovementioned and further starting
materials may be found in
the technical literature, for example Kunststoffhandbuch (transl. 'Plastics
Handbook'), Volume VII,
Polyurethane, Carl Hanser Verlag Munich, Vienna, 1st, 2nd and 3rd Editions
1966, 1983 and 1993.
Component H
Further auxiliaries and/or admixture agents H) can optionally be added to the
reaction mixture for
producing the rigid polyurethane foams. Mention may be made of, for example,
surface-active sub-
stances, foam stabilizers, cell regulators, fillers, dyes, pigments,
hydrolysis inhibitors, fungistatic
and bacteriostatic substances.
Possible surface-active substances are, for example, compounds which serve to
aid homogeniza-
tion of the starting materials and may also be suitable for regulating the
cell structure of the poly-
mers. Mention may be made of, for example, emulsifiers such as the sodium
salts of castor oil sul-
fates or of fatty acids and also salts of fatty acids with amines, e.g.
diethylamine oleate, diethano-
lamine stearate, diethanolamine ricinoleate, salts of sulfonic acids, e.g.
alkali metal or ammonium
salts of dodecylbenzenedisulfonic or dinaphthylmethanedisulfonic acid and
ricinoleic acid; foam
stabilizers such as siloxane-oxyalkylene copolymers and other
organopolysiloxanes, ethoxylated
alkylphenols, ethoxylated fatty alcohols, paraffin oils, castor oil esters or
ricinoleic esters, Turkey
CA 2862774 2019-10-09
19
red oil and peanut oil, and cell regulators such as paraffins, fatty alcohols
and dimethylpolysilox-
anes. Oligomeric acrylates having polyoxyalkylene and fluoroalkane radicals as
side groups are
also suitable for improving the emulsifying action, the cell structure and/or
for stabilizing the foam.
The surface-active substances are usually employed in amounts of from 0.01 to
10 parts by weight,
based (i.e., reckoned) on 100 parts by weight of component B).
For the purposes of the present invention, fillers, in particular reinforcing
fillers, are the customary
organic and inorganic fillers, reinforcing materials, weighting agents, agents
for improving the abra-
sion behavior in paints, coating compositions, etc., which are known per se.
Specific examples are:
inorganic fillers such as siliceous minerals, for example sheet silicates such
as antigorite, serpen-
tine, hornblendes, amphiboles, chrisotile and talc, metal oxides such as
kaolin, aluminum oxides,
titanium oxides and iron oxides, metal salts, such as chalk, barite and
inorganic pigments such as
cadmium sulfide and zinc sulfide and also glass, etc. Preference is given to
using kaolin (china
clay), aluminum silicate and coprecipitates of barium sulfate and aluminum
silicate and also natural
and synthetic fibrous minerals such as wollastonite, metal fibers and in
particular glass fibers of
various length, which may be coated with a size, Possible organic fillers are,
for example: carbon,
melamine, rosin, cyclopentadienyl resins and graft polymers and also cellulose
fibers, polyamide,
polyacrylonitrile, polyurethane, polyester fibers based on aromatic and/or
aliphatic dicarboxylic es-
ters and in particular carbon fibers.
The inorganic and organic fillers can be used individually or as mixtures and
are advantageously
added to the reaction mixture in amounts of from 0.5 to 50 wt%, preferably
from 1 to 40 wt%, based
on the weight of components A) to H), although the content of mats, nonwovens
and woven fabrics
of natural and synthetic fibers can reach values of up to 80 wt%, based on the
weight of compo-
nents A) to H).
Further information regarding the abovementioned other customary auxiliary and
admixture agents
may be found in the technical literature, for example the monograph by J.H.
Saunders and K.C.
Frisch "High Polymers" Volume XVI, Polyurethanes, Parts 1 and 2, Interscience
Publishers 1962
and 1964, or Kunststoff-Handbuch (transl. 'Plastics Handbook'), Polyurethane,
Volume VII, Hanser-
Verlag, Munich, Vienna, 1st and 2nd Editions, 1966 and 1983.
The present invention further provides a polyol component comprising:
10 to 90 wt% of polyetherester polyols B),
0 to 60 wt% of further polyester polyols C),
0.1 to 11 wt% of polyether polyols D),
2 to 50 wt% of flame retardants E),
CA 2862774 2019-10-09
CA 02862774 2014-06-30
1 to 45 wt% of blowing agents F),
0.5 to 10 wt% of catalysts G), and
0.5 to 20 wt% of further auxiliary and admixture agents H),
all as defined above and all based on the total weight of components B) to H),
wherein the wt% add
5 up to 100 wt%, and wherein the mass ratio of total components B) and C)
to component D) is at
least 7.
It is particularly preferable for the polyol component to comprise
10 50 to 90 wt% of polyetherester polyols B),
0 to 20 wt% of further polyester polyols C),
2 to 9 wt% of polyether polyols D),
5 to 30 wt% of flame retardants E),
1 to 30 wt% of blowing agents F),
15 0.5 to 10 wt% of catalysts G), and
0.5 to 20 wt% of further auxiliary and admixture agents H),
all as defined above and all based on the total weight of components B) to H),
wherein the wt% add
up to 100 wt%, and wherein the mass ratio of total components B) and C) to
component D) is at
least 7.5.
The mass ratio of the present invention of total components B) and optionally
C) to component D)
in the polyol components of the present invention is further preferably less
than 80, more preferably
less than 40, even more preferably less than 30, yet even more preferably less
than 20, yet still
even more preferably less than 16 and most preferably less than 14.
To produce the rigid polyurethane foams of the invention, the optionally
modified organic
polyisocyanates A), the specific polyetherester polyols B) of the invention,
optionally the further
polyester polyols C), the polyetherols D) and the further components E) to H)
are mixed in such
amounts that the equivalence ratio of NCO groups of the polyisocyanates A) to
the sum of the
reactive hydrogen atoms of the components B) and optionally C) and D) to H) is
1-6:1, preferably
1.6-5:1 and in particular 2.5-3.5:1.
The examples which follow illustrate the invention.
Examples
CA 02862774 2014-06-30
21
The hereinbelow specified polyester polyols (polyesterols 1 and 3) and
polyetherester polyols (pol-
yesterol 2 and polyesterol 4) were used.
Polyesterol 1 (comparator): Esterification product of 34 mol% of terephthalic
acid, 9 mol% of oleic
acid, 40 mol% of diethylene glycol and 17 mol% of glycerol with a hydroxyl
functionality of 2.33, a
hydroxyl number of 244 mg KOH/g and an oleic acid content of 20.3 wt% in the
polyesterol.
Polyesterol 2 (invention): Esterification product of 31 mol% of terephthalic
acid, 8 mol% of oleic
acid, 43 mol% of diethylene glycol and 18 mol% of a polyether based on
glycerol and ethylene ox-
ide having an OH functionality of 3 and a hydroxyl number of 535 mg KOH/g. The
polyester has a
hydroxyl functionality of 2.31, a hydroxyl number of 238 mg KOH/g and an oleic
acid content of
14.7 wt% in the polyesterol.
Polyesterol 3 (comparator): Esterification product of 30.5 mol% of phthalic
anhydride, 12 mol% of
oleic acid, 39.5 mol% of diethylene glycol and 18 mol% of trimethylolpropane
with a hydroxyl func-
tionality of 2.22, a hydroxyl number of 247 mg KOH/g and an oleic acid content
of 24.9 wt% in the
polyesterol.
Polyesterol 4 (invention): Esterification product of 25 mol% of phthalic
anhydride, 15 mol% of oleic
acid, 37 mol% of diethylene glycol and 23 mol% of a polyether based on
trimethylolpropane and
ethylene oxide having an OH functionality of 3 and a hydroxyl number of 610 mg
KOH/g. The poly-
ester has a hydroxyl functionality of 2.22, a hydroxyl number of 244 mg KOH/g
and an oleic acid
content of 24.5 wt% in the polyesterol.
Determination of curing and brittleness of the rigid polyurethane foam
The curing was determined by the bolt test. For this purpose, 2.5, 3, 4, 5, 6
and 7 minutes after
mixing of the components of the polyurethane foam in a polystyrene beaker, a
steel bolt with a
spherical cap 10 mm in radius was pressed by a tensile/compressive tester 10
mm deep into the
mushroom-shaped foam formed. The maximum force in N required here is a measure
of the curing
of the foam.
Brittleness was determined for the rigid polyisocyanurate foam by determining
the time at which the
CA 02862774 2014-06-30
22
surface of the rigid foam displayed visible zones of breakage in the bolt
test. Brittleness was further
determined subjectively directly after foaming by compressing the foam, and
graded on a scale
from 1 to 6, where 1 denotes a scarcely brittle foam and 6 a foam of high
brittleness.
Determining the self-reactivity of the polyurethane systems
The polyurethane systems described hereinbelow were adjusted to a unitary
fiber time by varying
the polyurethane catalyst concentration. When a system needed a lower
concentration of catalyst,
this was taken to mean that the system had higher self-reactivity.
Inventive Examples 1 and 2 and Comparative Examples 1 and 2
Production of rigid polyurethane foams (variant 1)
The isocyanates and also the isocyanate-reactive components were foamed up
together with the
blowing agents, catalysts and all further admixture agents at a constant
polyol:isocyanate mixing
ratio of 100:190.
Polyol component:
79 parts by weight of polyesterol as per inventive or comparative examples,
6 parts by weight of polyetherol from ethoxylated ethylene glycol having a
hydroxyl functionality
of 2 and a hydroxyl number of 190 mg KOH/g,
13 parts by weight of trischloroisopropyl phosphate (TCPP) as flame retardant,
2.0 parts by weight of Tegostab B8443 (silicone-containing) stabilizer.
Admixture agents:
15.0 parts by weight of S 80:20 pentane (consisting of 80 wt% n-pentane and
20 wt%
isopentane),
about 1.9 parts by weight of water,
1.6 parts by weight of potassium acetate solution (47 wt% in ethylene
glycol),
plus bis(2-dimethylaminoethyl) ether solution (70
wt% in dipropylene
CA 02862774 2014-06-30
23
glycol) for adjusting the fiber times, also called catalyst 1 herein-
below.
lsocyanate component:
190 parts by weight of Lupranat M50 (polymeric methylene(diphenyl
diisocyanate) (PMDI), having
a viscosity of about 500 mPa*s at 25 C from BASF SE).
The components were intensively mixed using a laboratory stirrer. Foam density
was adjusted to 32
+/- 1 g/L by varying the water content while keeping the amount of pentane
constant at 15.0 parts.
Fiber time was further adjusted to 49 +/- 1 s by varying the proportion of
bis(2-dimethylaminoethyl)
ether solution (70 wt% in dipropylene glycol) (catalyst 1).
The results are summarized in table 1.
Table 1:
Polyesterol Polyesterol Polyesterol
Polyesterol
1 2 3 4
curing
2.5 min 36 39 32 35
3 min 47 47 39 42
4 min 66 63 57 56
sum (2.5; 3 and 4 min) 149 149 128 133
brittleness (subjective) 6 2.5 6 2
breakage in bolt test 3 min no breakage 2.5 min no breakage
catalyst 1 1 0.4 0.9 0.6
It is clearly apparent here that inventive polyester polyols 2 and 4 reduce
the brittleness of the in-
sulant and increase the self-reactivity of the systems without having any
adverse effect on foam
curing.
CA 02862774 2014-06-30
24
Inventive Examples 3 and 4 and Comparative Examples 3 and 4
Production of rigid polyurethane foams (variant 2)
Foaming was done similarly to variant 1 except that the chemical blowing agent
water used in vari-
ant 1 was replaced in variant 2 by formic acid solution (85 wt% in water) as
chemical blowing agent.
The components were intensively mixed using a laboratory stirrer. Foam density
was adjusted to 32
+/- 1 g/L by varying the amount of formic acid solution (85 wt% in water)
while keeping the pentane
content constant at 15.0 parts. Fiber time was further adjusted to 51 +/- 1 s
by varying the propor-
tion of bis(2-dimethylaminoethyl) ether solution (70 wt% in dipropylene
glycol; (catalyst 1)).
The results are summarized in table 2.
Table 2:
Polyesterol 1 Polyesterol 2 Polyesterol 3 Polyesterol 4
curing
2.5 min 28 34 24 31
3 min 36 42 31 38
4 min 55 56 46 50
sum (2.5; 3 and 4 min) 119 132 101 119
brittleness (subjective) 6 4,5 6 3
breakage in bolt test 2.5 min 4 min 3 min 5 min
catalyst 1 3.2 1.6 2.7 2.2
It is clearly apparent here that inventive polyesterols 2 and 4 reduce the
brittleness of the insulant
and increase the self-reactivity of the systems without having any adverse
effect on foam curing.
