Note: Descriptions are shown in the official language in which they were submitted.
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Polyesterols for producing rigid polyurethane foams
Description
The invention relates to polyesterols, to a process for producing rigid
polyurethane foams using
the polyesterols, to the rigid polyurethane foams themselves and also to their
use for producing
sandwich elements having rigid or flexible outer layers.
The production of rigid polyurethane foams by reacting organic or modified
organic di- or
polyisocyanates 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 polyurethane 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 publications.
In what follows, the terms "polyester polyol", "polyesterol", "polyester
alcohol" and the
abbreviation "PESOL" are used interchangeably.
Customary polyester polyols are polycondensates of aromatic and/or aliphatic
dicarboxylic acids
and alkanediols and/or ¨triols, or ether diols. It is also possible to process
polyester scrap,
especially polyethylene terephthalate (PET) and/or polybutylene terephthalate
(PBT) scrap, into
polyester polyols. 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 terephthalate. 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
terephthalic acid or phthalic anhydride) are used to produce rigid
polyurethane (PU) foams, the
high viscosity 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 difficult.
EP-A 1 058 701 discloses aromatic polyester polyols of low viscosity, which
are obtained by
transesterifying a mixture of phthalic acid derivatives, diols, polyols and
hydrophobic fat-based
materials.
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In addition, certain systems for producing rigid PU foams, for example those
employing glycerol
as comparatively high-functional 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
satisfactorily 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,
preferentially 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 defects 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.
Smoke gas evolution by rigid polyurethane or polyisocyanurate foam insulants
in the event of a
fire is problematical.
The invention thus has for its object to provide polyesterols for the
production of rigid
polyurethane or polyisocyanurate foams which in the event of a fire result in
reduced smoke gas
evolution by the rigid polyurethane or polyisocyanurate foams produced
therewith. The
invention further has for its object to provide rigid polyurethane or
polyisocyanurate foams
having reduced smoke gas evolution in the event of a fire.
This object is achieved by a polyesterol B) obtainable by reaction of
b1) from 10 to 70 mol%, preferably from 20 to 60 mol%, more preferably from 25
to 50 mol%
and especially from 30 to 40 mol% of at least one compound selected from the
group
consisting of terephthalic acid, dimethyl terephthalate, polyethylene
terephthalate, phthalic
anhydride, phthalic acid and isophthalic acid,
b2) from 0.8 to 4.5 mol%, preferably from 1.0 to 3.8 mol%, more preferably
from 1.1 to
3.2 mol% and especially from 1.2 to 2.5 mol% and specifically from 1.3 to 2.0
mol% of a
fatty acid triglyceride,
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b3) from 10 to 70 mol%, preferably from 20 to 60 mol%, more preferably from 30
to 55 mol%
and especially from 40 to 50 mol% of a diol selected from the group consisting
of ethylene
glycol, diethylene glycol and polyethylene glycol,
b4) from 5 to 50 mol% preferably from 10 to 40 mol%, more preferably from 12
to 30 mol%
and especially from 14 to 25 mol% of a polyether polyol having a functionality
above 2,
wherein at least 200 mmol of component b4) are used per kg of polyesterol B),
wherein the sum total of components b1) to b4) is 100 mol%.
The object is further achieved by a process for producing rigid polyurethane
foams comprising
the reaction of
at least one polyisocyanate,
B) at least one polyesterol obtainable by reaction of
b1) from 10 to 70 mol%, preferably from 20 to 60 mol%, more preferably from 25
to 50 mol%
and especially from 30 to 40 mol% of at least one compound selected from the
group
consisting of terephthalic acid, dimethyl terephthalate, polyethylene
terephthalate, phthalic
anhydride, phthalic acid and isophthalic acid,
b2) from 0.8 to 4.5 mol%, preferably from 1.0 to 3.8 mol%, more preferably
from 1.1 to
3.2 mol% and especially from 1.2 to 2.5 mol% and specifically from 1.3 to 2.0
mol% of a
fatty acid triglyceride,
b3) from 10 to 70 mol%, preferably from 20 to 60 mol%, more preferably from 30
to 55 mol%
and especially from 40 to 50 mol% of a dial selected from the group consisting
of ethylene
glycol, diethylene glycol and polyethylene glycol,
b4) from 5 to 50 mol% preferably from 10 to 40 mol%, more preferably from 12
to 30 mol%
and especially from 14 to 25 mol% of a polyether polyol having a functionality
above 2,
wherein at least 200 mmol of component b4) are used per kg of polyesterol B),
wherein the sum total of components b1) to b4) is 100 mol%,
C) optionally one or more further polyester polyols other than those of
component B),
D) optionally one or more polyether polyols,
E) optionally one or more flame retardants,
F) one or more blowing agents,
G) one or more catalysts, and
H) optionally further auxiliaries or admixture agents.
The present invention also provides a polyol component comprising the
aforementioned
components B) to H), wherein the mass ratio of total components B) and
optionally C) to
component D) is at least 1.
The present invention further provides rigid polyurethane foams obtainable by
the process of
the present invention and also their use for producing sandwich elements
having rigid or flexible
outer layers. For the purposes of the present invention, rigid polyurethane
foams are also to be
understood as meaning rigid polyisocyanurate foams, which are specific rigid
polyurethane
foams.
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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
component of the present invention.
Component B
Hereinbelow the terms "polyester polyol" and "polyesterol" are used
interchangeably as are the
terms "polyether polyol" and "polyetherol".
Component b1) preferably comprises at least one compound from the group
consisting of
terephthalic acid (TPA), dimethyl terephthalate (DMT), polyethylene
terephthalate (PET),
phthalic anhydride (PA) and phthalic acid, more preferably consisting of
terephthalic acid (TPA),
dimethyl terephthalate (DMT) and polyethylene terephthalate (PET). It is
particularly preferable
for component b1) to comprise at least one compound from the group consisting
of terephthalic
acid and dimethyl terephthalate (DMT). Component b1) consists specifically of
terephthalic acid.
Terephthalic acid and/or DMT in component b1) lead to polyesters B) having
particularly good
fire protection properties.
The amount in which component b2) is used is preferably from 1.0 to 3.8 mol%,
more preferably
from 1.1 to 3.2 mol%, more specifically from 1.2 to 2.5 mol%, and even more
specifically from
1.3 to 2.0 mol%. The fatty acid triglyceride is preferably soybean oil,
rapeseed oil, tallow or a
mixture thereof. In a specific embodiment, soybean oil is concerned. In a
further specific
embodiment, beef tallow is concerned. The fatty acid triglyceride serves inter
alia to improve the
blowing agent solubility in the production of rigid polyurethane foams,
although a comparatively
low amount of fatty acid triglyceride b2) in polyesterol B) surprisingly has a
favorable effect on
smoke gas density in the event of a fire, i.e., smoke gas density decreases.
The amount in which diol b3) is used is preferably from 20 to 60 mol%, more
preferably from 30
to 55 mol% and especially from 40 to 50 mol%. This diol is preferably at least
one compound
from the group consisting of polyethylene glycol (PEG), diethylene glycol
(DEG) and
monoethylene glycol (MEG), particular preference being given to diethylene
glycol (DEG) and
monoethylene glycol (MEG) and especial preference to diethylene glycol (DEG).
Polyethylene
glycol is to be understood as meaning triethylene glycol and higher oligomers
of ethylene glycol.
Useful polyethylene glycols generally have a number-average molecular weight
ranging from 50
to 600 g/mol, preferably from 55 to 400 g/mol and especially from 60 to 200
g/mol and
specifically from 62 g/mol to 150 g/mol.
The amount in which polyether polyol b4) is used is preferably from 10 to 40
mol%, more
preferably from 12 to 30 mol% and especially from 14 to 25 mol%, and is at
least 200 mmol,
preferably at least 400 mmol, more preferably at least 600 mmol, especially at
least 800 mmol
and specifically at least 1000 mmol of component b4) per kg of polyesterol B).
Component b4)
is preferably an alkoxylated triol or polyol, more preferably an alkoxylated
triol and even more
preferably a polyether prepared by the addition of ethylene oxide or propylene
oxide, preferably
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ethylene oxide, onto glycerol or trimethylolpropane, preferably glycerol, as
starter molecule_ The
use of ethylene oxide leads to rigid foams having improved fire behavior.
In a preferred embodiment of the present invention the starter molecule is
alkoxylated to
5 prepare component b4) by using a catalyst from the group consisting of
potassium hydroxide
(KOH) and aminic alkoxylation catalysts, in which case the use of aminic
alkoxylation catalysts
is preferred, since the polyetherols thus obtained can be used in the
subsequent esterification
without workup, while the polyether first has to be neutralized and separated
off when KOH is
used as alkoxylation catalyst. Preferred aminic alkoxylation catalysts are
selected from the
group consisting ,of dimethylethanolamine (DMEOA), imidazole and imidazole
derivatives and
also mixtures thereof, particular preference being given to imidazole.
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.
The storage stability of component B) is particularly high as a result.
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 on the part of
component B).
The OH number of polyether polyol b4) is preferably in the range from 150 to
1250 mg KOH/g,
preferably from 300 to 950 mg KOH/g and more preferably from 500 to 800 mg
KOH/g. In this
range, particularly favorable mechanical properties and/or fire protection
properties are
achievable.
In a particularly preferred embodiment of the invention, the polyether polyol
b4) consists of the
reaction product of trimethylolpropane or glycerol, preferably glycerol, with
ethylene oxide, 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, and imidazole is used as alkoxylation catalyst.
In an especially preferred embodiment of the invention, the polyether polyol
b4) consists of the
reaction product of trimethylolpropane or glycerol, preferably glycerol, with
ethylene oxide, 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, imidazole is used as alkoxylation catalyst, the
aliphatic or
cycloaliphatic diol b3) is diethylene glycol, and component b2) is soybean
oil, rapeseed oil or
tallow, preferably tallow.
The number-weighted average functionality of polyester 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.
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Polyester polyols B) are obtainable by polycondensing components b1) to b4) in
the absence of
catalysts or preferably in the presence of esterification catalysts,
advantageously in an
atmosphere of inert gas such as nitrogen in the melt at temperatures of 150 to
280 C,
preferably 180 to 260 C optionally under reduced pressure to the desired acid
number, which is
advantageously less than 10 and preferably less than 2. In a preferred
embodiment, the
esterification mixture is polycondensed at the abovementioned temperatures to
an acid number
of 80 to 20, preferably 40 to 20, under atmospheric pressure and subsequently
under a
pressure of less than 500 mbar, preferably 40 to 400 mbar. Possible
esterification catalysts
include 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 diluent and/or
entrainer agents, for
example benzene, toluene, xylene or chlorobenzene, to remove the water of
condensation by
azeotropic distillation.
To prepare the polyester polyols B), the organic polycarboxylic acids and/or
derivatives and
polyhydric alcohols are advantageously polycondensed in a molar ratio of 1:1
to 2.2, preferably
t1.05 to 2.1 and more preferably 1:1.1 to 2Ø
The resulting polyester polyols B) 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 polyester polyols B) according to the present invention is
generally at least
10 wt%, preferably at least 20 wt%, more preferably at least 40 wt% and
specifically at least
50 wt%, based on total components B) to H).
Rigid polyurethane foams are obtained according to the process of the present
invention by
using the specific polyester polyols B) described above alongside construction
components
known per se, which will now be discussed in detail.
Component A
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., isocyanate
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) will
be not less than 2.
Useful polyisocyanates A) include the well-known aliphatic, cycloaliphatic,
araliphatic and
preferably aromatic polyfunctional isocyanates. 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
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isocyanates useful as polyisocyanate is two (and so the polyfunctional
isocyanates in question
are referred to hereinbelow 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 diioscyanate,
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 (I
PD!), 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'- 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), 1,5-
naphthylene diisocyanate (ND!), 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 diisocyanate, IPDI), 1,4- and/or 1,3-
bis(isocyanatomethyl)cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 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
conversion 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 dilsocyanat
(MDI), especially 2,2`-
MDI or 2,4`-MDI or 4,4`-MDI or oligomeric MDI, which is also known as
polyphenylpolymethylene 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 derivative;
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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). Polyisocyanates may preferably also be constructed from
mixtures of
monomeric aromatic diisocyanates 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. Polymeric 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, preferably 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 polyfunctional 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
Lupranat .
The functionality of component A) is preferably at least two, more preferably
at least 2.2 and
especially 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
mmol/g, 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 reciprocal relationship between the isocyanate group content in
mmol/g and the so-
called equivalence 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 (A) more preferably comprises
oligomeric
diphenylmethane diisocyanate and has a functionality of at least 2.4.
The viscosity of component A) can vary within wide limits. The viscosity of
component A) is
preferably in the range from 100 to 3000 mPa-s and more preferably in the
range from 200 to
2500 mPa-s.
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Component C
Useful polyester polyols C) differ from polyesterols B) and can be prepared,
for example, from
organic dicarboxylic acids having 2 to 12 carbon atoms, preferably aromatic
ones, or mixtures 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 individually 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 mixture 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 diols, 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 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 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 polyesterols B) to the further polyester polyols C) is
generally at least 0.1,
preferably at least 0_5, more preferably at least 1.0 and especially at least
2.
One especially preferred embodiment does not utilize any further polyester
polyols C).
CA 02874910 2014-11-27
Component D
One or more polyether polyols D) can be used as component D. Polyetherols D)
can be
prepared by known methods, for example from one or more alkylene oxides having
from 2 to 4
carbon atoms by anionic polymerization using alkali metal hydroxides, e.g.,
sodium or
5 potassium hydroxide, or alkali metal alkoxides, e.g., sodium methoxide,
sodium or potassium
ethoxide or potassium isopropoxide, or aminic alkoxylation catalysts, such as
dimethylethanolamine (DME0A), imidazole and/or imidazole derivatives, with use
of at least
one starter molecule comprising 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,
10 boron fluoride etherate, or bleaching 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, triethylenetetramine, 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.
Further possible starter molecules are: alkanolamines such as ethanolamine,
N-methylethanolaniine and N-ethylethanolamine, dialkanolamines, such as
diethanolamine, N-
methyldiethanolamine and N-ethyldiethanolamine and trialkanolamines, e.g.,
triethanolamine,
and ammonia.
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), possibly polyoxypropylene polyols and polyoxyethylene
polyols, more
preferably 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.
CA 02874910 2014-11-27
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One preferred embodiment of the invention utilizes an alkoxylated diol,
preferably an
ethoxylated diol, 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
components B) to H).
The mass ratio of total components B) and C) to component D) is generally
greater than 1,
preferably greater than 2, more preferably greater than 7, 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) is further
generally 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 specifically less than 13.
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
brominated 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-dibromo-
propyl) phosphate, tetrakis(2-chloroethyl) ethylenediphosphate, dimethyl
methanephosphonate,
diethyl diethanolaminomethylphosphonate and also commercial halogen-comprising
flame re-
tardant polyols. By way 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
flame retardants such as red phosphorus, preparations comprising red
phosphorus, aluminum
oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and
calcium sulfate,
expandable 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
ammonium 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 pref-
erably liquid at room temperature. Particular preference is given to TCPP,
DEEP, TEP, DMPP
and DPK.
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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 compo-
nents 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 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 preferably 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 oxalate and ethyl
acetate and
halogenated hydrocarbons such as methylene chloride,
dichloromonofluoromethane,
difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane,
chlorodifluoroethanes, 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 mixtures 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 together with physical blowing agents, in which case formic acid-water
mixtures or pure
formic acid together with pentane isomers or mixtures of pentane isomers are
preferred.
The blowing agents are either wholly or partly dissolved in the polyol
component (i.e.
B+C+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".
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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
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%,
preferably 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
component B). The addition of water, formic acid or formic acid-water mixture
can take place in
combination 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 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
triethylamine, tributylamine, dimethylbenzylamine,
dicyclohexylmethylamine,
dimethylcyclohexylamine, N,N,N',N'-tetramethyldianninodiethyl ether,
bis(dimethylamino-
propyl)urea, N-methylmorpholine or N-ethylmorpholine, N-cyclohexylmorpholine,
N,N,N',N'-
tetramethylethylenediamine, N,N,N,N-tetramethylbutanediamine, N,N,N,N-
tetramethylhexane-
1,6-diamine, pentamethyldiethylenetriamine, bis(2-dinnethylaminoethyl) ether,
dimethyl-
piperazine, N-dimethylaminoethylpiperidine, 1,2-dimethylimidazole, 1-
azabicyclo[2.2.0]octane,
1,4-diazabicyclo[2.2.2]octane (Dabco) and alkanolamine compounds, such as
triethanolamine,
triisopropanolamine, N-methyldiethanolamine and
N-ethyldiethanolamine,
dimethylaminoethanol, 2-(N,N-dinnethylaminoethoxy)ethanol,
N,N',N"-tris(dialkylamino-
alkyl)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 diethylhexoate 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,
tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, alkali
metal
hydroxides such as sodium hydroxide and alkali metal alkoxides such as sodium
mettioxide 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 catalyst combination,
based (Le.,
reckoned) on 100 parts by weight of component B). It is also possible to allow
the reactions to
14
proceed without catalysis. In this case, the catalytic activity of amine-
initiated 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 formation 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 (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, surfaceactive substances, 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
homogenization of the starting materials and may also be suitable for
regulating the
cell structure of the polymers. Mention may be made of, for example,
emulsifiers such
as the sodium salts of castor oil sulfates or of fatty acids and also salts of
fatty acids
with amines, e.g. diethylamine oleate, diethanolamine 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 siloxaneoxyalkylene copolymers and other
organopolysiloxanes,
ethoxylated alkylphenols, ethoxylated fatty alcohols, paraffin oils, castor
oil esters or
ricinoleic esters, Turkey red oil and peanut oil, and cell regulators such as
paraffins,
fatty alcohols and dimethylpolysiloxanes. The abovedescribed 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
CA 2874910 2019-10-29
15
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 the 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 abrasion 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, serpentine, 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 esters 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 the 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 components 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, lnterscience Publishers 1962 and 1964, or Kunststoff-Handbuch (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:
from 10 to 90 wt% of polyesterols B),
from 0 to 60 wt% of further polyester polyols C),
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15a
from 0 to 11 wt% of polyether polyols D),
from 2 to 50 wt% of flame retardants E),
from1 to 45 wt% of blowing agents F),
from 0.001 to 10 wt% of catalysts G), and
from 0.5 to 20 wt% of further auxiliary and admixture agents H),
each as defined above and each based on the total weight of components B) to
H),
wherein the 35 wt% sum to 100 wt%, and wherein the mass ratio of total
components
B) and C) to component D) is at least 1.
It is particularly preferable for the polyol component to comprise
from 50 to 90 wt% of polyesterols B),
from 0 to 20 wt% of further polyester polyols C),
from 2 to 9 wt% of polyether polyols D),
from 5 to 30 wt% of flame retardants E),
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CA 02874910 2014-11-27
16
from 1 to 30 wt% of blowing agents F),
from 0.5 to 10 wt% of catalysts G), and
from 0.5 to 20 wt% of further auxiliary and admixture agents H),
each as defined above and each based on the total weight of components B) to
H), wherein the
wt% sum to 100 wt%, and wherein the mass ratio of total components B) and C)
to component
D) is at least 2.
The mass ratio of total components B) and optionally C) to component D) in the
polyol
components of the present invention is further generally 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 most preferably less than 13.
To produce the rigid polyurethane foams of the invention, the optionally
modified organic
polyisocyanates A), the specific polyester 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:
Polyesterol 1 (not in accordance with the present invention):
Esterification product of terephthalic acid (30.5 mol%), oleic acid (9.2
mol%), diethylene glycol
(36.6 mol%) and a polyether polyol (23.7 mol%) based on trimethylolpropane and
ethylene
oxide with an OH functionality of 3 and a hydroxyl number of 610 mg KOH/g,
prepared in the
presence of imidazole as alkoxylation catalyst. The polyether was used in the
subsequent
esterification without workup. Polyesterol 1 had a hydroxyl functionality of
2.49 and a hydroxyl
number of 245 mg KOH/.
Polyesterol 2 (in accordance with the present invention):
Esterification product of terephthalic acid (35.4 mol%), soybean oil (2.1
mol%), diethylene glycol
(44.3 rnor/o) and a polyether polyol (18.2 mor/o) based on trimethylolpropane
and ethylene
oxide with an OH functionality of 3 and a hydroxyl number of 610 mg KOH/g,
prepared in the
presence of imidazole as alkoxylation catalyst. The polyether polyol was used
in the subsequent
esterification without workup. Polyesterol 2 had a hydroxyl functionality of
2.48 and a hydroxyl
number of 251 mg KOH/.
Polyesterol 3 (in accordance with the present invention):
Esterification product of terephthalic acid (36.0 mol%), soybean oil (1.4
mol%), diethylene glycol
(46.9 mol%) and a polyether polyol (15.7 mol%) based on trimethylolpropane and
ethylene
17
oxide with an OH functionality of 3 and a hydroxyl number of 610 mg KOH/g,
prepared
in the presence of imidazole as alkoxylation catalyst. The polyether polyol
was used in
the subsequent esterification without workup. Polyesterol 3 had a hydroxyl
functionality
of 2.46 and a hydroxyl number of 253 mg KOH/.
Polyesterol 4 (not in accordance with the present invention):
Esterification product of terephthalic acid (37.0 mol%), soybean oil (0.7
mol%),
diethylene glycol (48.2 mol%) and a polyether polyol (14.1 mol%) based on
trimethylolpropane and ethylene oxide with an OH functionality of 3 and a
hydroxyl
number of 610 mg KOH/g, prepared in the presence of imidazole as alkoxylation
catalyst. The polyether polyol was used in the subsequent esterification
without
workup. Polyesterol 4 had a hydroxyl functionality of 2.49 and a hydroxyl
number of
250 mg KOH/.
Determination of processability:
Processability was determined by observing the foam formation process. Large
bubbles of blowing agent which burst at the surface of the foam and thus tear
open the
surface of the foam were referred to as "blowouts" and the system was classed
as not
satisfactorily processable. If this unsatisfactory behavior was not observed,
processability was classed as satisfactory.
Smoke gas production
Smoke gas production was measured in a cone calorimeter using a helium-neon
laser
and a photodiode and determined in accordance with ISO 5660-2 as total smoke
production [m2/m2] and average specific extinction area (ASEA) [m2/kg].
Production of rigid polyurethane foams (variant 1):
The isocyanates and the isocyanate-reactive components were foamed up at a
constant polyol component/isocyanate mixing ratio of 100:160 together with the
blowing agents, catalysts and all further admixture agents.
Polyol component:
40.0 parts by weight of polyesterol as per inventive or comparative
examples;
CA 2874910 2019-10-29
17a
27.0 parts by weight of polyether polyol with OH number about 490 mg
KOH/g,
prepared by polyaddition of propylene oxide onto a sucrose-
glycerol mixture as starter molecule (66.4 wt% PO, 20.3
wt% sucrose, 13.3 wt% glycerol);
5.5 parts by weight of polyetherol consisting of the ether of ethylene
glycol and
ethylene oxide with hydroxyl functionality 2 and hydroxyl
number 200 mg KOH/g;
25 parts by weight of trischlorisopropyl phosphate (TCPP) as flame
retardant;
2.5 parts by weight of NiaxTM Silicone L 6635 stabilizer (silicon
containing
stabilizer);
additives to polyol component:
5.5 parts by weight of Pentane S 80:20 (80 wt% n-pentane and 20 wt%
isopentane);
about 2.6 parts by weight of water;
1.5 parts by weight of potassium acetate solution (47 wt% in ethylene
glycol);
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18
about 1.1 parts by weight of dimethylcyclohexylamine
Isocyanate component:
160 parts by weight of LupranatO M50 (polymeric methylenediphenyl diisocyanate
(PMDI) with
viscosity about 500 mPa*s at 25 C).
Sandwich elements 50 mm thick were produced by the double belt process. Foam
density was
adjusted to 38 +/- 1 g/L by varying the water content while keeping the
pentane content
constant at 5.5 parts. Fiber time was controlled to 25 +/- 1 s by varying the
proportion of
dimethylcyclohexylamine.
Production of rigid polyurethane foams (variant 2):
The isocyanates and the isocyanate-reactive components were foamed up at a
constant polyol
coniponent/isocyanate mixing ratio of 100:180 together with the blowing
agents, catalysts and
all further admixture agents.
Polyol component:
40.0 parts by weight of polyesterol as per inventive or comparative examples;
27.0 parts by weight of polyether polyol with OH number about 490 mg KOH/g,
prepared by
polyaddition of propylene oxide onto a sucrose-glycerol mixture as
starter molecule (composition like variant 1);
5.5 parts by weight of polyetherol consisting of the ether of ethylene
glycol and ethylene
oxide with hydroxyl functionality 2 and hydroxyl number 200 mg KOH/g;
parts by weight of trischlorisopropyl phosphate (TCPP) as flame retardant;
25 2.5 parts by weight of Niax Silicone L 6635 stabilizer
(silicon containing stabilizer);
additives to polyol component:
5.5 parts by weight of Pentane S 80:20 (80 wt% n-pentane and 20 wt%
isopentane);
about 2.8 parts by weight of water;
1.5 parts by weight of potassium acetate solution (47 wt% in ethylene
glycol);
about 1.3 parts by weight of dimethylcyclohexylamine.
lsocyanate component:
180 parts by weight of LupranatO M50 (polymeric methylenediphenyl diisocyanate
(PMDI) with
viscosity about 500 mPa*s at 25'C).
Sandwich elements 50 mm thick were produced by the double belt process. Foam
density was
adjusted to 38 +/- 1 g/L by varying the water content while keeping the
pentane content
constant at 5.5 parts. Fiber time was controlled to 25 +/- 1 s by varying the
proportion of
dimethylcyclohexylamine.
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19
Production of rigid polyurethane foams (variant 3):
The isocyanates and the isocyanate-reactive components were foamed up at a
constant polyol
component/isocyanate mixing ratio of 100:200 together with the blowing agents,
catalysts and
all further admixture agents.
Polyol component:
40_0 parts by weight of polyesterol as per inventive or comparative examples;
27.0 parts by weight of polyether polyol with OH number about 490 mg KOH/g,
prepared by
polyaddition of propylene oxide onto a sucrose-glycerol mixture as
starter molecule (composition like variant 1);
5.5 parts by weight of polyetherol consisting of the ether of ethylene
glycol and ethylene
oxide with hydroxyl functionality 2 and hydroxyl number 200 mg KOH/g;
25 parts by weight of trischlorisopropyl phosphate (TCPP) as flame
retardant;
2.5 parts by weight of Niax Silicone L 6635 stabilizer (silicon containing
stabilizer)
additives to polyol component:
5.5 parts by weight of Pentane S 80:20 ((80 wt% n-pentane and 20 wt%
isopentane);
about 3.1 parts by weight of water;
1.5 parts by weight of potassium acetate solution (47 wt% in ethylene
glycol);
about 1.5 parts by weight of dimethylcyclohexylamine.
lsocyanate component:
200 parts by weight of LupranatO M50 (polymeric methylenediphenyl diisocyanate
(PMDI) with
viscosity about 500 mPa*s at 25'C).
Sandwich elements 50 mm thick were produced by the double belt process. Foam
density was
adjusted to 38 +/- 1 g/L by varying the water content while keeping the
pentane content
constant at 5.5 parts. Fiber time was controlled to 25 +/- 1 s by varying the
proportion of
dimethylcyclohexylamine.
The results are summarized in Table 1.
Table 1: Results of attempts to produce 50 mm thick sandwich elements by
double belt
process
Version 1 2 3
mixing ratio 160 180 200
polyesterol 1
visual assessment good good good
processing satisfactory satisfactory satisfactory
polyesterol 2
visual assessment good I good good
CA 02874910 2014-11-27
processing satisfactory satisfactory satisfactory
polyesterol 3
visual assessment good good surface defects
processing satisfactory satisfactory blowouts
polyesterol 4
visual assessment surface defects surface defects surface defects
processing blowouts blowouts blowouts
Table 1 shows that the processing properties of inventive rigid polyurethane
foams improve as
the proportion of fatty acid triglyceride increases in the polyesterol used.
The rigid foams
produced from polyesterols 1 and 2 were obtained in all variants, i.e., with
all mixing ratios
5 (160/180/200), in a satisfactory manner with good surface appearance. The
rigid foam produced
from polyester 3 was only obtained with surface defects and in an
unsatisfactory manner in the
case of variant 3 (mixing ratio 200). The rigid foam produced from polyester 4
could not be
satisfactorily obtained in any variant or any mixing ratio. The elements from
all three variants
had distinct surface defects.
Table 2: Results of smoke production from cone calorimeter tests to ISO
5660 Parts 1 and 2
with foam samples from 50 mm thick sandwich elements produced by double belt
process
Variant 1
mixing ratio 160
polyesterol 1
total smoke production [rn2/m2] 990
ASEA [m2/kg] 523
polyesterol 2
total smoke production [m2/rn2] 929
ASEA [m2/kg] 509
polyesterol 3
total smoke production [m2/m2] 832
ASEA [m2/kg] 457
polyesterol 4
total smoke production [m2/m2] 650
AS EA [rn2/kg] 363
Table 2 shows that smoke gas production decreases with decreasing fatty acid
triglyceride
content of polyesterol used.
