U.S. patent application number 10/843016 was filed with the patent office on 2004-10-21 for polyisocyanate polyaddition products.
Invention is credited to Arlt, Andreas, Chakrabarti, Sarbananda, Kreyenschmidt, Martin, Rodewald, Dieter.
Application Number | 20040209969 10/843016 |
Document ID | / |
Family ID | 7912207 |
Filed Date | 2004-10-21 |
United States Patent
Application |
20040209969 |
Kind Code |
A1 |
Arlt, Andreas ; et
al. |
October 21, 2004 |
Polyisocyanate polyaddition products
Abstract
The polyisocyanate polyaddition products comprise hydrophobic
compounds plus at least one further compound selected from the
group consisting of: (i) organic, cyclic compounds having a
molecular weight of from 200 to 3000 g/mol, (ii) salts of metals of
transition groups I, II and/or VIII, (iii) organic and/or inorganic
acid anhydrides, (iv) cyclic sulfonic esters and/or sulfones, (v)
lactones, lactams and/or cyclic esters and/or (vi)
.alpha.,.beta.-unsaturated carboxylic acids,
.alpha.,.beta.-unsatura- ted carboxylic acid derivatives,
.alpha.,.beta.-unsaturated ketones and/or
.alpha.,.beta.-unsaturated aldehydes.
Inventors: |
Arlt, Andreas; (Weisenheim
am Berg, DE) ; Chakrabarti, Sarbananda; (Mannheim,
DE) ; Kreyenschmidt, Martin; (Lohne, DE) ;
Rodewald, Dieter; (Bad-Essen, DE) |
Correspondence
Address: |
BASF CORPORATION
LEGAL DEPARTMENT
1609 BIDDLE AVENUE
WYANDOTTE
MI
48192
US
|
Family ID: |
7912207 |
Appl. No.: |
10/843016 |
Filed: |
May 11, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10843016 |
May 11, 2004 |
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10273010 |
Oct 17, 2002 |
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10273010 |
Oct 17, 2002 |
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09744509 |
Jan 24, 2001 |
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6495611 |
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Current U.S.
Class: |
521/99 ;
521/109.1; 521/131; 521/132; 521/172; 521/173; 521/175 |
Current CPC
Class: |
C08G 2110/0083 20210101;
C08G 18/36 20130101; C08G 18/4288 20130101; C08G 18/6204 20130101;
C08G 2110/0008 20210101; C08G 18/1825 20130101 |
Class at
Publication: |
521/099 ;
521/109.1; 521/131; 521/132; 521/172; 521/173; 521/175 |
International
Class: |
C08G 018/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 1999 |
DE |
19928676.0 |
Jun 15, 2000 |
WO |
PCT/EP00/05496 |
Claims
1. A polyisocyanate polyaddition product comprising hydrophobic
compounds plus at least one further compound and/or derivative
thereof reactive toward primary amines, said at least one further
compound being selected from the group of cyclic sulfonic esters
and sulfones and mixtures thereof, wherein said hydrophobic
compounds are selected from the group of reaction products of
castor oil with alkylene oxides, epoxidized fatty acid esters, low
molecular weight hydroxy-functional polyolefins and oleochemical
polyols based on a C.sub.9-C.sub.22-fatty acid and prepared by ring
opening of epoxidized triglycerides.
2. A flexible polyurethane foam comprising the polyaddition product
of claim 1.
3-4. (Cancelled)
5. A mattress or furniture upholstery and/or carpet backing
comprising a flexible polyurethane foam as claimed in claim 2.
6. (canceled)
7. A method of reducing the primary amine content of polyisocyanate
polyaddition products comprising the step of providing in said
polyaddition product a hydrophobic compound and at least one
further compound and/or derivative thereof, reactive toward primary
amines, said at least one further compound being selected from the
group of cyclic sulfonic esters and sulfones and mixtures thereof,
wherein said hydrophobic compounds are selected from the group of
reaction products of castor oil with alkylene oxides, epoxidized
fatty acid esters, low molecular weight hydroxy-functional
polyolefins and oleochemical polyols based on a
C.sub.9-C.sub.22-fatty acid and prepared by ring opening of
epoxidized triglycerides.
8. (canceled)
9. The polyisocyanate polyaddition product of claim 1 wherein the
at least one further compound and/or derivative thereof is reactive
toward and/or complexes with tertiary amines.
10. A polyisocyanate polyaddition product comprising a hydrophobic
flexible polyurethane foam which comprises hydrophobic compounds
plus at least one further compound and/or derivative thereof
reactive toward primary amines, said at least one further compound
being selected from the group of cyclic sulfonic esters and
sulfones and mixtures thereof, wherein said hydrophobic compounds
are selected from the group of reaction products of castor oil with
alkylene oxides, epoxidized fatty acid esters, low molecular weight
hydroxy-functional polyolefins and oleochemical polyols based on a
C.sub.9-C.sub.22-fatty acid and prepared by ring opening of
epoxidized triglycerides, wherein the at least one further compound
and/or derivative thereof is reactive toward and/or complexes with
tertiary amines.
11. The polyisocyanate polyaddition product of claim 10 wherein
said hydrophobic compounds each have at least two isocyanate
reactive groups.
12. (canceled)
13. A process for making a foamed polyisocyanate polyaddition
product comprising reacting: a) compounds which are reactive toward
isocyanates, and b) isocyanates, in the presence of c) hydrophobic
compounds selected from the group of reaction products of castor
oil with alkylene oxides, epoxidized fatty acid esters, low
molecular weight hydroxy-functional polyolefins and oleochemical
polyols based on a C.sub.9-C.sub.22-fatty acid and prepared by ring
opening of epoxidized triglycerides, d) at least one further
compound, reactive toward primary amines or capable of forming a
derivative reactive toward primary amines, selected from the group
of cyclic sulfonic esters and sulfones and mixtures thereof, and e)
catalysts, blowing agents, and, optionally, auxiliaries and/or
additives, to form a hydrophobic polyisocyanate polyaddition
product wherein said at least one further compound and/or
derivative thereof is present in the product and is reactive toward
primary amines.
14-16. (Canceled)
17. A polyisocyanate polyaddition product as claimed in claim 1,
wherein said low molecular weight hydroxy-functional polyolefins
have a molecular weight of from 500 to 8000 g/mol.
18. A method as claimed in claim 7, wherein said low molecular
weight hydroxy-functional polyolefins have a molecular weight of
from 500 to 8000 g/mol.
19. A polyisocyanate polyaddition product as claimed in claim 10,
wherein said low molecular weight hydroxy-functional polyolefins
have a molecular weight of from 500 to 8000 g/mol.
20. A process as claimed in claim 13, wherein said low molecular
weight hydroxy-functional polyolefins have a molecular weight of
from 500 to 8000 g/mol.
Description
[0001] The present invention relates to polyisocyanate polyaddition
products comprising hydrophobic compounds plus at least one further
compound selected from the group consisting of: (i) organic, cyclic
compounds having a molecular weight of from 200 to 3000 g/mol, (ii)
salts of metals of transition groups I, II and/or VIII, (iii)
organic and/or inorganic acid anhydrides, (iv) cyclic sulfonic
esters and/or sulfones, (v) lactones, lactams and/or cyclic esters
and/or (vi) .alpha.,.beta.-unsaturated carboxylic acids,
.alpha.,.beta.-unsaturated carboxylic acid derivatives,
.alpha.,.beta.-unsaturated ketones and/or
.alpha.,.beta.-unsaturated aldehydes, preferably selected from the
group consisting of: (i), (iii), (iv), (v) and/or (vi),
particularly preferably selected from the group consisting of
(iii), (iv) and/or (vi). Furthermore, the invention relates to a
process for producing these polyisocyanate polyaddition products,
in particular mattresses or furniture upholstery and/or carpet
backing. The invention also relates to the use of hydrophobic
compounds for reducing the formation and/or the content of primary
amines in polyisocyanate polyaddition products and/or for reducing
the water uptake of polyisocyanate polyaddition products, in
particular flexible polyurethane foams.
[0002] The production of polyisocyanate polyaddition products by
reacting polyisocyanates with compounds which are reactive toward
isocyanates in the presence of catalysts which accelerate the
reaction of the substances which are reactive toward isocyanates
with isocyanates and, if desired, blowing agents, additives and/or
auxiliaries is generally known.
[0003] Like other plastics, polyisocyanate polyaddition products
are subject to aging processes which generally, lead to a
deterioration in the use properties as time goes on. Important
aging influences are, for example, hydrolysis, photooxidation and
thermal oxidation which lead to rupture of bonds in the polymer
chains. In the case of polyisocyanate polyaddition products, for
example polyurethanes, hereinafter also referred to as PURs,
especially the action of moisture and even more the combination of
moisture and elevated temperature results in hydrolytic cleavage of
the urethane and urea bonds.
[0004] This cleavage is not only reflected in a significant
deterioration in the use properties but also leads to formation of
primary aromatic amines, e.g. toluenediamine (TDA) and
diaminodiphenylmethane (MDA), or primary aliphatic amines such as
hexamethylenediamine or isophoronediamine.
[0005] As experiments have found, amine formation is influenced by
a series of parameters. In particular, high temperatures above
80.degree. C. in combination with high atmospheric humidity lead to
hydrolytic cleavage of the urethane and urea bonds. Such conditions
are of importance in some specific applications of flexible PUR
foams.
[0006] A further parameter which has a significant influence on the
formation of primary amines is the type and amount of catalysts
used. As has been able to be shown in various experiments, the
catalysts which are present in polyurethane systems and are
necessary for the urethanization and blowing reaction also catalyze
the hydrolytic redissociation reaction to a considerable extent.
The presence of catalysts is thus a critical precondition for the
hydrolysis of the urethane and urea bonds. Furthermore, it has been
able to be shown that the efficiency of the hydrolysis is highly
dependent on the activity and the type of catalyst, and also on
whether the catalyst remains in the system or can migrate out of
the material. In particular, tertiary amine catalysts having
reactive functional groups such as OH and NH.sub.2 considerably
accelerate amine formation by lowering the activation energy for
the cleavage reaction. The functional groups result in
incorporation of the catalysts into the PUR network formed and the
products produced using them have the advantage of lower odor and
fogging problems since the catalysts cannot escape by diffusion
after production of the PUR product. The same applies to
formulations comprising polyols which have been prepared using
primary or secondary amines as initiator molecules and thus have
catalytically active centers. Such polyols have been increasingly
used in recent times. In the case of formulations which comprise
such constituents and are exposed to particularly hot and humid
conditions in specific applications, the formation of primary
amines as dissociation products cannot be ruled out. In contrast,
in the case of foams produced using amine catalysts which contain
no functional groups capable of being built into the structure, the
catalysts are generally given off only a short time after
manufacture or during aging of the foam. In the case of such foams,
hot and humid conditions lead to significantly lower amine
contents.
[0007] As compounds which reduce the aromatic amine content of
flexible polyurethane foams, U.S. Pat. No. 4,211,847, GB 1 565 124
and DE-A 29 46 625 make use of sterically hindered cycloaliphatic
monoisocyanates and monothioisocyanates. Owing to their steric
hindrance and their lower reactivity compared to aromatic
isocyanates, these isocyanates react to only a slight extent during
the foaming reaction, so that free isocyanate is available for
reaction with any aromatic amines present after the foaming
reaction is complete. Disadvantages of these known teachings are
that the compounds mentioned are relatively expensive and,
especially the two last-named compounds, also participate at least
partially in the urethanization reaction despite their steric
hindrance and do not react only after the foaming reaction with
aromatic amine formed. In addition, these isocyanates tend to
migrate out of the finished foam because of their low vapor
pressure and thus pose a further health hazard due to the
occurrence of free isocyanate.
[0008] DE-A 42 32 420 discloses the use of
.alpha.,.beta.-unsaturated ester carboxylates for producing
polyurethane foams which have an improved compressive strength and
elongation at break. In that document, salts of
.alpha.,.beta.-unsaturated ester carboxylates are used as catalysts
for the NCO/water reaction. In an aside, it is stated that the
compounds are, due to the presence of olefinic double bonds
adjacent to the carboxylate groups, capable of addition of amino
groups which are formed during the slow aging of the foam. A
disadvantage of these compounds is their catalytic action which has
an adverse effect on the foaming reaction. A catalytic action of
additives for reducing the amine contents of finished PUR foams is,
however, not desirable since this leads, as described above, to
further and accelerated formation of primary amines.
[0009] Hydrolysis inhibitors for polyurethanes containing ester
groups are described in DE-A 23 31 796, FR 1 550 562 and GB 1 014
974. The increase in the hydrolysis resistance of the PUR products
is usually based on an improvement in the mechanical properties
after storage under hot and humid conditions. DE-A 23 31 796
describes the addition of epoxy compounds in order to avoid
hydrolysis of the ester groups in PUR products. For the same
purpose, FR 1 550 562 claims alkyl carbonates and GB 1 014 974
claims carbodiimides in combination with a, compound containing
enol groups.
[0010] DD 238 992 describes epoxidized synthetic products such as
triglycerides, alkyl epoxystearates, etc., and epoxidized natural
products such as soya oil as hydrolysis inhibitors for polyurethane
elastomers. However, the improvement in the hydrolysis resistance
(increased hardness, tensile strength and elongation at break) is
restricted to polyurethane elastomers containing polyesters as
polyol component. DD 298 246 claims a polyol component for
producing noncellular polyurethane moldings having an improved
hydrolysis resistance. The improvement in the hydrolysis resistance
is achieved here by addition of fatty amines.
[0011] A similar reaction mixture is claimed in DE-A 3 443 341. The
improvement in the elongation at break of possibly cellular
polyurethanes is achieved here by means of a mixture of an
inorganic filler, a metal salt of a fatty acid and a
hydrophobicizing agent such as a fatty acid amide, fatty alcohol or
a natural or synthetic wax.
[0012] GB 2 313 128 discloses castor oil and derivatives and also
polyols based on polybutadiene and saturated hydrocarbons
(>C.sub.10) for increasing the resistance of polyurethanes to
discoloration. It is also possible to use hydrophobic compounds
without OH groups, for example olefins, paraffins and also animal
and vegetable oils.
[0013] U.S. Pat. No. 5,549,841 claims a process for producing
flexible PUR foams having an improved compressive set for use in a
tropical or subtropical climate. This improvement is achieved by
the use of polyols having a variable ethylene oxide content or a
variable ethylene oxide end cap in combination with polymer
polyols. The polymer polyol comprises a vinyl polymer dispersion in
a polyoxyalkylene base polyol.
[0014] EP-A 672 698 describes a process for producing polyurethanes
by addition of reaction products of polyalkylenepolyamines and
natural fats or oils. The foams produced using these products are
largely closed-celled and therefore have a rigid foam character.
Such formulations are unsuitable for flexible foam
applications.
[0015] A further document in which hydrophobic PUR foams are
described is EP-A 933. The foams produced with addition of fatty
acids, fatty acid esters, adducts of fatty acids and EO/PO and also
fatty acid amides have a high absorption capability in respect of,
oil and possibly halogen-containing, hydrophobic compounds.
[0016] WO 99/00428 discloses flexible polyurethane foams which are
produced using hydroxylated polydienes.
[0017] It is an object of the present invention to modify
polyisocyanate polyaddition products, in particular polyurethane
foams, in such a way that the hydrolytic cleavage of urethane and
urea bonds and thus, in particular, the formation of aromatic
amines is prevented or at least reduced. The compounds should be
inexpensive and readily available and should be able to display
their effect in the finished foam without further after-treatment.
In addition, they should affect the foam properties as little as
possible.
[0018] We have found that this object is achieved by the
polyisocyanate polyaddition products described at the outset and
the use of the hydrophobic compounds likewise described at the
outset.
[0019] It has been found that the extent of hydrolytic
redissociation of urethane and urea bonds is dependent to a
considerable degree on the penetration of moisture into the foam
matrix. It was thus necessary to find additives which hinder the
penetration of moisture, especially in foams which are exposed to
hot and humid conditions. These additives should have no
significant effect on the foaming reaction and the properties of
the foams.
[0020] The penetration of moisture into the foam matrix was able to
be influenced by the degree of hydrophilicity or hydrophobicity of
the foams. It was found that, because of its water-repellent
properties, a hydrophobic foam takes up less moisture than a
hydrophilic foam. The problem described could accordingly be solved
by increasing the hydrophobicity of the foams. Surprisingly, it was
found that these technical teachings according to the present
invention not only enable the penetration of water into, in
particular, the flexible polyurethane foam to be prevented but also
enable the formation of primary amines to be reduced.
[0021] The hydrophobic compounds used according to the present
invention are preferably employed in the generally known processes
for producing polyisocyanate polyaddition products, preferably
polyurethanes which may contain isocyanurate and/or urea
structures, particularly preferably flexible polyurethane foams.
The present invention therefore also provides a process for
producing flexible polyurethane foams having the properties
according to the present invention in respect of water uptake
and/or water adsorption by producing the flexible polyurethane foam
in the presence of the hydrophobic compounds used according to the
present invention.
[0022] The hydrophobic compounds used according to the present
invention preferably contain groups which are reactive toward
isocyanates, more preferably from 2 to 4 reactive groups, in
particular hydroxyl groups.
[0023] Preferred hydrophobic compounds have a molecular weight of
from 500 to 8000 g/mol and have at least one continuous carbon
framework, i.e. a carbon framework connected by means of
carbon-carbon bonds, having at least 8, preferably at least 10,
carbon atoms.
[0024] The hydrophobic compounds used are therefore preferably
reaction products of castor oil with alkylene oxides, epoxidized
fatty acid esters, low molecular weight hydroxy-functional
polyolefins preferably having a molecular weight from 500 to 8000
g/mol and/or oleochemical polyols based on a C.sub.9-C.sub.22-fatty
acid and prepared by ring opening of epoxidized triglycerides.
[0025] In particular, it is possible to use modified, where the
term modified refers, for example, to ring-opened fatty acid
esters, or unmodified fatty acid esters, oils, in particular
vegetable oils, and/or polyolefins, for example:
[0026] oleochemical polyols, e.g. triglycerides, based on a
C.sub.9-C.sub.22-fatty acid and prepared, for example, by ring
opening of epoxidized fatty acid esters, for example triglycerides,
and preferably having a hydroxyl number (OHN) of from 50 to 300 mg
KOH/g, where the epoxy content can be varied from 0% to 10%
depending on the completeness of ring opening;
[0027] fatty acid esters, preferably epoxidized fatty acid esters,
preferably having a hydroxyl number (OHN) of from 30 to 500 mg
KOH/g, particularly preferably from 100 to 200 mg KOH/g, preferably
based on a C.sub.9-C.sub.22-fatty acid, e.g. prepared by
transesterification of oleochemical polyols with
C.sub.1-C.sub.30-alkanols, e.g. alkyl epoxystearates, alkyl
epoxytallates, alkyl epoxytetrahydrophthalates, alkyl oleates,
dialkyl adipates, dialkyl sebacates, di(methylcyclohexyl)
phthalate, dicyclohexyl phthalate, diisotridecyl phthalate, hexyl
oleylcetyl phthalate, di(oleylcetyl) phthalate, dioctyl adipate,
diisodecyl adipate, dibutyl sebacate, dioctyl sebacate, isobutyl
stearate, the 2-ethylhexyl ester of epoxidized soya oil, isobutyl
esters of fatty acids, the isobutyl ester of tallow acid,
2-ethylhexyl stearate and/or tetrahydrofurfuryl oleate;
[0028] reaction products of natural vegetable oils, e.g. castor
oil, linseed oil and/or soya oil, with ethylene oxide and/or
propylene oxide, preferably propylene oxide, advantageously having
an OHN of from 50 to 200, particularly preferably from 80 to 90, mg
KOH/g and/or
[0029] low molecular weight polyolefins, preferably having a
molecular weight of from 500 to 8000 g/mol, which are preferably
hydroxy-functionalized at both ends and/or have an epoxidized
isoprene unit at one or both ends.
[0030] Replacement of part of the polyol component, for example in
the production of flexible polyurethane foams, by the hydrophobic
compounds described enables the hydrophobicity of the foams to be
increased so that the penetration of moisture is significantly
inhibited. This is a tremendous advantage for, in particular, foams
which are exposed to hot and humid conditions (hot steam
disinfection or in future sterilization of hospital mattresses, hot
steam cleaning of upholstered furniture and carpets). In the case
of foams which have been produced using such polyols, the entry of
moisture is inhibited to such a degree that the occurrence of
hydrolytic cleavage of urethane and urea bonds under hot and humid
conditions is significantly reduced.
[0031] The formation of primary aromatic amines such as
toluenediamine or diaminodiphenylmethane associated with this
cleavage reaction is likewise significantly reduced by this
measure. The stabilizing action of the polyols used according to
the present invention is advantageously based on a prevention of
the formation of primary amines, while the addition of other
additives, e.g. the abovementioned sterically hindered isocyanates,
results in only primary amine which has already been formed being
chemically bound. The hydrophobic compounds used according to the
present invention do not pose a health hazard and can be easily
incorporated into the polyol component because of their good
compatibility with the constituents of the polyol component. The
hydrophobic compounds used according to the present invention
counter both a deterioration in the mechanical properties,
particularly when exposed to hot and humid conditions, and also the
formation of primary amines, in particular primary aromatic amines,
for example 2,2'-, 2,4'-and/or 4,4'-MDA and/or 2,4- and/or
2,6-TDA.
[0032] The use of oleochemical polyols, in particular, gives
open-celled foams. Varying the proportion of these polyols allows
the open cell content of PUR foams to be set in a targeted
manner.
[0033] The use of the hydrophobic compounds described makes it
possible to obtain foams which consist in large part of natural,
i.e. regenerating, raw materials. Since the production of molded
PUR foams and slabstock foams is increasingly looked at from an
ecological perspective, finished products containing a relatively
high proportion of recyclable components should be produced in
future so as to conserve resources.
[0034] To produce the polyisocyanate polyaddition products, the
hydrophobic compounds are preferably used in an amount of from 0.2
to up to 100.0% by weight, based on the weight of all the
isocyanate-reactive compounds employed.
[0035] To produce the polyisocyanate polyaddition products, it is
also advantageous to use (i) organic, cyclic compounds having a
molecular weight of from 200 to 3000 g/mol, preferably from 200 to
1300 g/mol, hereinafter also referred to as "macrocycles".
[0036] As a result of the use of the macrocycles, the macrocycles
form complexes with tertiary amines which have been used as
catalysts in the production of the polyisocyanate polyaddition
products, in particular in the finished polyisocyanate polyaddition
product, and the tertiary amines in the complex with the
macrocycles can no longer display their catalytic activity, i.e.
they are blocked. Since the complexed amine catalysts in the
finished polyisocyanate polyaddition products are no longer capable
of catalyzing the abovementioned hydrolytic redissociation of
urethane and urea bonds, the macrocycles counter both a
deterioration in the mechanical properties, in particular on
exposure to hot and humid conditions, and also the formation of
primary amines, in particular primary aromatic amines, for example
2,2'-, 2,4'- and/or 4,4'-MDA and/or 2,4- and/or 2,6-TDA.
Furthermore, the formation of complexes of the macrocycles used
according to the present invention with primary amines, for example
primary aromatic amines, can hinder migration or extraction of
these amines from the polyisocyanate polyaddition product.
Migration or extraction of the amine catalysts, too, from the
product is hindered by such complexation. The resulting reduction
in odor and fogging problems is reinforced, in particular, by the
additives used according to the present invention being able to be
at least partially incorporated into the polyurethane network due
to the presence of OH groups. The inclusion of primary and/or
tertiary amines by the macrocycles which have been fixed in this
way leads to the amines being immobilized in the foam matrix.
[0037] Macrocycles, e.g. cyclodextrins, are capable of the
inclusion of water molecules as well as amines, which further
reduces the occurrence of hydrolytic cleavage reactions and thus
additionally counters the formation of primary amines.
[0038] As macrocycles, it is possible to use generally known
compounds, for example cyclodextrins, resorcinarenes, cyclophanes
and/or cyclocalixarenes, each of which may be in modified form.
[0039] Such cyclodextrins, which may also have a branched
structure, are mentioned in, for example, U.S. Pat. No. 5,063,251,
column 2, lines 55 to 63, and DE-A 1 96 14 441, page 2, lines 46
and 47. Suitable cyclocalixarenes are described in U.S. Pat. No.
4,642,362, column 2, line 34 to column 7, line 68.
[0040] Preference is given to using .alpha.-cyclodextrin,
.beta.-cyclodextrin, y-cyclodextrin, reaction products of these
cyclodextrins with alkylene oxides, 4-tert-butylcalix[4]arene,
4-tert-butylcalix-[6]arene, 4-tert-butylcalix[8]arene,
4-sulfocalix[4]arene, 4-sulfocalix[6]arene, 4-sulfocalix[8]arene,
C-methylcalix[4]resorcinarene, C-undecylcalix[4]resorcinarene,
tetra-N-pentylcalix[4]resorcinarene and/or [2.2]paracyclophane,
particularly preferably .beta.-cyclodextrin,
4-tert-butylcalix[6]arene, 4-sulfocalix[6]arene and/or
[2.2]paracyclophane.
[0041] The macrocycles can be used in the A and/or B components or
in the constituents of these components, preferably in the
isocyanate component in order to avoid complexation of the amine
catalysts which are customarily present in the A component before
the polyurethane product has been produced. If the macrocycles are
not soluble in either the A component or the B component, they are
dispersed in powder form in one of the two components and
subsequently processed in this form.
[0042] To produce the polyisocyanate polyaddition products, the
macrocycles are preferably used in an amount of from 0.2 to 5% by
weight, based on the weight of the compounds which are reactive
toward isocyanates.
[0043] Furthermore, (ii) salts of metals of transition groups I, II
and/or VIII, hereinafter also referred to generally as "metal
salts", are also advantageously used for producing the
polyisocyanate polyaddition products. For the purposes of the
present invention, the terms "salts of metals" or "metal salts"
also include the cations of the metals specified in complexed
form.
[0044] As a result of the use of the metal salts, the metal ions
form complexes with tertiary amines used as catalysts in the
production of the polyisocyanate polyaddition products, and the
tertiary amines in the complex with the metals can no longer
display their catalytic activity, i.e. they are blocked. Since the
complexed amine catalysts in the finished polyisocyanate
polyaddition products are no longer capable of catalyzing the
abovementioned hydrolytic redissociation of urethane and urea
bonds, the metal salts counter both a deterioration in the
mechanical properties, in particular on exposure to hot and humid
conditions, and also the formation of primary amines, in particular
primary aromatic amines, for example 2,2'-, 2,4'-and/or 4,4'-MDA
and/or 2,4- and/or 2,6-TDA. Furthermore, the formation of complexes
of the metal salts used according to the present invention with
primary amines, for example primary aromatic amines, can hinder
migration or extraction of these amines from the polyisocyanate
polyaddition product. Such complexation prevents migration or
extraction of the amine catalysts, too, from the product, which ie
reflected in improved fogging behavior of the foams. In addition,
the metal salts can act as oxidation catalysts and accelerate
oxidative degradation of any aromatic amines formed.
[0045] As metal salts, it is possible to use generally known salts
of metals, for example salts of inorganic and/or organic acids,
e.g. mineral acids, of the transition groups indicated, for example
salts of the following metals: Cu, Ni, Co, Fe, Zn, Ag, Pd and Rh,
preferably Cu, Ni and/or Fe salts, where the metals can be in any
stable oxidation state.
[0046] As anion in the metal salts, it is possible for generally
customary anions to be present, for example, chloride, sulfate,
nitrate and/or carboxylates having from 1 to 20 carbon atoms.
Furthermore, it is possible to use salts of complexed cations of
the same metals with known ligands, for example monoalkylamines,
alkylenediamines, phenanthroline, acetylacetone, aromatic
phosphines such as triphenylphosphine, aliphatic phosphines such as
tributylphosphine, salicylaldehyde and/or 1,4-diazabutadiene
derivatives; it is preferred that no tertiary amines are used as
ligands. Examples of metal salts or salts of their complex cations
are the following compounds: Cu(II) sulfate, Cu(II) chloride,
Ni(II) sulfate, Co(II) chloride, Cu(II) naphthenate, Fe(II)
chloride, Cu(I) chloride, Fe(III) chloride, Cu(II)
acetate-ethylenediamine complex, Fe(II) phenanthroline complex
(generally known as a redox indicator under the name ferroin),
Cu(I)-nitratobistriphenylphosphine complex, [glyoxal
bis(cyclohexylimine)]chlorocopper(I) complex.
[0047] The central atom and ligand of the metal-ligand complex are
preferably chosen so that the central atom of the complex can form
complexes with primary aromatic amines or tertiary aliphatic amines
or catalyze their oxidation. The complex between MDA and/or TDA or
the amine catalysts and the metal cation of the complex used is
preferably more stable, i.e. the dissociation constant is greater,
than the complex cation used. Preference is given to using Cu(II)
sulfate, Ni(II) sulfate, Cu(II) acetate, Fe(II) phenanthroline
complex, Cu(II)-acetate-ethylenedia- mine complex, Cu(II)
naphthenate and/or Cu(I)-nitratobistriphenylphosphine complex as
metal salt.
[0048] To produce the polyisocyanate polyaddition products, the
metal salts are preferably used in an amount of from 0.05 to 5% by
weight, based on the weight of the sum of the metal salts and the
compounds which are reactive toward isocyanates.
[0049] The metal salts can be used in the A and/or B components or
in the constituents of these components, preferably in the
isocyanate component.
[0050] Furthermore, it can be useful to use (iii) organic and/or
inorganic acid anhydrides, particularly preferably at least one
carboxylic anhydride, for producing the polyisocyanate polyaddition
products. The acid anhydride(s) is/are preferably used in an amount
of from 0.01 to 20% by weight, based on the weight of the
isocyanates and the acid anhydrides.
[0051] When acid anhydrides are employed, the anhydrides in the
polyisocyanate polyaddition products are hydrolyzed to the acids,
particularly under hot and humid conditions. These acids resulting
from the hydrolysis block the amine catalysts which may be present
in the products, for example by protonation or reaction, and thus
prevent acceleration of the redissociation of the urethane bonds.
In addition, the acid anhydrides used according to the present
invention bind any free amino groups formed by undesired cleavage
of urethane bonds.
[0052] The acid anhydrides are thus used in polyisocyanate
polyaddition products to stabilize the polyisocyanate polyaddition
products, in particular polyurethanes, against cleavage of the
urethane and urea bonds, for example by blocking amine catalysts by
protonating the catalysts or by reaction with the catalysts. In
addition, the acid anhydrides can be employed in polyisocyanate
polyaddition products to react with amino groups in the
polyisocyanate polyaddition products, for example to form
amides.
[0053] In this way, the diffusion of amines out of the
polyisocyanate polyaddition products and the redissociation of the
urethane bond, for example by amine catalysts present in the
polyisocyanate polyaddition products, can be reduced.
[0054] It was surprisingly found that acid anhydrides used in the
production of polyisocyanate polyaddition products survive the
production process almost unscathed and do not participate
significantly in the reaction. This is particularly true when the
acid anhydrides are used in admixture with isocyanates, since this
component is usually free of water and hydrolysis of the anhydrides
can thus be avoided. Use of the acid anhydrides in admixture with
compounds which are reactive toward isocyanates can be particularly
advantageously carried out by adding the acid anhydrides to this
mixture only just before production of the polyisocyanate
polyaddition products, since the compounds which are reactive
toward isocyanates usually contain small amounts of water. The acid
anhydrides used according to the present invention can also be
stable in the isocyanate-reactive compounds over a prolonged period
of time.
[0055] Surprisingly, it has been found that the acid anhydrides are
stable in admixture with isocyanates at room temperature, i.e.
25.degree. C., and the isocyanate groups do not react or do not
react significantly with the anhydride groups.
[0056] As anhydrides, it is possible to use organic or inorganic
acid anhydrides, for example also polyanhydrides, preferably
carboxylic anhydrides, for example anhydrides of aliphatic,
cycloaliphatic, araliphatic and/or aromatic carboxylic acids having
usually from 1 to 10, preferably 1 or 2, carboxyl groups, with
mixed anhydrides prepared from at least two different carboxylic
acids also being able to be used. Polyanhydrides obtainable from
dicarboxylic and/or polycarboxylic acids or copolymers of
anhydrides and various alkenes can also be used as anhydrides. The
carboxyl groups of the compounds are preferably converted to a
large extent, particularly preferably completely, into the
corresponding anhydrides. The compounds (ii) usually have a
molecular weight of from 60 to 1000000 g/mol. Examples which may be
mentioned are: acetic anhydride, propionic anhydride, butyric
anhydride, pentanoic anhydride, hexanoic anhydride, heptanoic
anhydride, octanoic anhydride, dimethylolpropionic anhydride,
adipic anhydride, fumaric anhydride, mesaconic anhydride,
methylenemalonic anhydride, trimellitic anhydride, ethylene glycol
4,4'-bis(anhydrotrimellitate), 2-acetyl-1,3-glyceryl
4,4'-bisanhydrotrimellitate, decanedioic anhydride, dodecanedioic
anhydride, azelaic anhydride, pimelic anhydride, brassylic
anhydride, citraconic anhydride, itaconic anhydride,
naphthalene-1,8-dicarboxylic anhydride,
naphthalene-1,2-dicarboxylic anhydride, chlorendic anhydride,
1,2,3,6-tetrahydrophthalic anhydride, mellophanic anhydride,
benzene-1,2,3,4-tetracarboxylic anhydride,
benzene-1,2,3-tricarboxylic anhydride, benzoic anhydride,
biphenyl-3,3'-4,4'-tetracarboxylic anhydride,
biphenyl-2,2'-3,3'-tetracarboxylic anhydride,
naphthalene-2,3,6,7-tetracarboxylic anhydride,
naphthalene-1,2,4,5-tetrac- arboxylic anhydride,
naphthalene-1,4,5,8-tetracarboxylic anhydride,
decahydronaphthalene-1,4,5,8-tetracarboxylic anhydride,
4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic
anhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic
anhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic
anhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic
anhydride, phenanthrene-1,3,9,10-tetracarboxylic anhydride,
perylene-3,4,9,10-tetrac- arboxylic anhydride,
bis(2,3-dicarboxyphenyl)methane anhydride,
bis(3,4-dicarboxyphenyl)methane anhydride,
1,1-bis(2,3-dicarboxyphenyl) ethane anhydride,
1,1-bis(3,4-dicarboxyphenyl) ethane anhydride,
2,2-bis(2,3-dicarboxyphenyl)propane anhydride, 2,2-bis
(3,4-dicarboxyphenyl)propane anhydride, bis(3,4-dicarboxyphenyl)
sulfone anhydride, bis(3,4-dicarboxyphenyl) ether anhydride,
ethylenetetracarboxylic anhydride, butane-1,2,3,4-tetracarboxylic
anhydride, cyclopentane-1,2,3,4-tetracarboxylic anhydride,
pyrrolidine-2,3,4,5-tetracarboxylic anhydride,
pyrazine-2,3,5,6-tetracarb- oxylic anhydride, mellitic anhydride,
thiophene-2,3,4,5-tetracarboxylic anhydride,
benzophenone-3,3',4,4'-tetracarboxylic anhydride, maleic anhydride,
glutaric anhydride, pyromellitic anhydride, phthalic anhydride,
isophthalic and/or terephthalic anhydride, benzoic anhydride,
phenylacetic anhydride, cyclohexylalkane anhydrides, malonic
anhydride, succinic anhydride, polymaleic anhydride, anhydrides
based on adducts of maleic acid and styrene, dodecenylsuccinic
anhydride, anhydrides of maleic acid and any alkylenes, for example
n-octylenesuccinic anhydride, n-dodecylenesuccinic anhydride and/or
copolymers of anhydrides and any further monomers such as isobutene
and maleic anhydride, poly(ethylene-co-butyl acrylate-co-maleic
dianhydride) and/or poly(styrene-co-maleic anhydride), where the
diacids or polyacids are partially or preferably completely in the
form of anhydrides. The anhydrides of the diacids or polyacids can,
insofar as it is sterically possible, be either intermolecular or
intramolecular.
[0057] Preference is given to using anhydrides based on the
following compounds: pyromellitic acid, succinic acid, maleic acid,
polymaleic anhydride, glutaric acid, which may also contain a
variety of side groups, and/or copolymers of these anhydrides with
all conceivable monomers which are polymerizable with anhydrides or
acids.
[0058] Very particular preference is generally given to anhydrides
which dissolve readily in the isocyanates and/or the compounds
which are reactive toward isocyanates, preferably the
isocyanates.
[0059] Furthermore, it is possible to use (iv) cyclic sulfonic
esters, also known as sultones, and/or sulfones, i.e. compounds
containing sulfonyl groups, preferably unsaturated sulfones. The
cyclic sulfonic esters and sulfones are hereinafter also referred
to collectively as "sulfur compounds". It has surprisingly been
found that the addition of the sulfur compounds leads to
significantly reduced primary amine contents. The reaction of
primary amines can occur under relatively mild conditions. Apart
from the reaction of primary amine already formed to give less
problematical compounds, the addition of sulfur compounds, in
particular sultones, prevents the formation of the primary amines.
The mechanism leading to this reduced amine formation is based on
the deactivation of the tertiary amine catalysts present, which,
after the polyurethane product has been produced, contribute to
catalysis of the hydrolytic cleavage of urethane and urea bonds and
thus to the formation of primary amines.
[0060] The added sultones, in particular, are hydrolyzed during the
foaming reaction as a result of the heat generated to form the
corresponding sulfonic acids. These sulfonic acids are in turn
capable of reacting with tertiary amines by protonating the
catalytically active nitrogen atom. This counters not only the
formation of primary amines but also the associated deterioration
in the mechanical properties during aging of the polyurethane
product. As a particular advantage of the additives used according
to the present invention, it has surprisingly been found that there
is even an improvement in the mechanical properties before aging. A
further positive effect associated with this hydrolysis of the
sultones is that a major part of the water which penetrates is
consumed in this reaction and is no longer available for the
cleavage of urethane and urea bonds. In order to prevent premature
hydrolysis of the sultones prior to the foaming reaction, they are
preferably dissolved in the isocyanate component.
[0061] In unsaturated sulfones, the sulfonyl group causes, as a
result of the partial positive charge on the sulfur atom, such a
strong polarization of the C.dbd.C double bond that this is capable
of adding primary amines under very mild conditions. The primary
amine content of polyisocyanate polyaddition products can be
significantly reduced by the addition of unsaturated sulfones as a
result of reaction to form unproblematical compounds. In addition,
sulfones also lead to an improvement in the mechanical properties
of the polyisocyanate polyaddition products.
[0062] The addition of sultones and sulfones can reduce the
diffusion or migration of primary amines out of the polyurethane
products. In hydrolyzed form, sultones improve the fogging behavior
by preventing diffusion of tertiary amine catalysts as a result of
the reaction of these with the hydrolyzed sultones.
[0063] In the case of brominated sultones (e.g.
tetrabromo-2-sulfobenzoic anhydride) and sulfones, an increase in
the flame resistance of the foams produced therewith has also been
found.
[0064] Accordingly, the sulfur compounds counter both a
deterioration in the mechanical properties, particularly on
exposure to hot and humid conditions, and also the formation of
primary amines, in particular primary aromatic amines, for example
2,2'-, 2,4'-and/or 4,4'-MDA and/or 2,4- and/or 2,6-TDA.
[0065] The additives used according to the present invention have
been found to be particularly effective in PUR formulations which
contain tertiary amines having reactive functional groups as
catalysts.
[0066] As sulfur compounds, it is possible to use generally known
compounds, preferably sultones and/or unsaturated sulfones.
[0067] Examples are: cyclic esters of aliphatic and aromatic
sulfonic acids, known as sultones, e.g. 1,3-propanesultone,
1,4-butanesultone, 2,4-butanesultone, 2,3-benzopropanesultone,
tolylsultone, 2-sulfobenzoic cycloanhydride,
tetrabromo-2-sulfobenzoic cycloanhydride, tetraiodo-2-sulfobenzoic
cycloanhydride, 1-naphthol-8-sulfonic sultone, carbyl sulfate
and/or triphenylmethane dyes containing sultone groups, e.g. phenol
red, pyrogallol red, pyrocatechol violet, thymol blue, bromothymol
blue, p-xylenol blue, bromoxylenol blue, bromocresol green,
bromophenol blue, tetrabromophenol blue, chlorophenol red, cresol
red, xylenol orange, bromophenol red, nitrophenolsulfonephthalein,
sulfonefluorescein and/or bromopyrogallol red, preferably
1,3-propanesultone, 1,4-butanesultone, 2,4-butanesultone,
2-sulfobenzoic cycloanhydride, tetrabromo-2-sulfobenzoic
cycloanhydride and 1-naphthol-8-sulfonic sultone.
[0068] Unsaturated sulfones which can be used are, for example,
butadiene sulfone, divinyl sulfone, benzyl allyl sulfone, allyl
sulfone, thionaphthene 1,1-dioxide and/or p-tolyl vinyl sulfone,
preferably butadiene sulfone.
[0069] To produce the polyisocyanate polyaddition products, the
sulfur compounds are preferably used in an amount of from 0.01 to
20% by weight, based on the weight of the polyisocyanate
polyaddition product.
[0070] Furthermore, it is possible to use (v) lactones, lactams
and/or cyclic esters, hereinafter also referred to as
"inhibitors".
[0071] The addition of the inhibitors in PUR foam formulations
surprisingly leads to significantly reduced contents of primary
amines. As inhibitors to be used according to the present invention
for reducing the primary amine content in polyurethane products, we
have accordingly found lactones or cyclic esters and lactams. As
experiments have shown, there are various mechanisms which
contribute to this reduction. The hydrolysis of lactones in the
presence of moisture to form hydroxycarboxylic acids is known from
the literature. The carboxylic acid formed by hydrolysis of the
inhibitor is capable of protonating the tertiary N atom in the
amine catalyst. As a result of the catalytically active N atom
being blocked with formation of a quaternary N atom, the amine
catalyst loses its catalytic activity in respect of the hydrolytic
redissociation of urethane and urea bonds. This counters a
deterioration in the mechanical properties of the polyisocyanate
polyaddition products, in particular the flexible foams, especially
when exposed to hot and humid conditions, and also the formation of
primary amines, in particular primary aromatic amines, for example
2,2'-, 2,4'- and/or 4,4'-MDA and/or 2,4- and/or 2,6-TDA. The
addition of the inhibitors reduces the hydrolysis of urethane and
urea bonds in two ways: as mentioned by deactivating the amine
catalysts present and also as a result of a major part of the water
which penetrates being consumed in the hydrolysis of the lactones
and lactams added and no longer being available for the cleavage of
urethane and urea bonds. Moreover, the inhibitors are also capable
of reacting with primary amine which has already been formed to
give hydroxycarboxamides or aminocarboxamides.
[0072] The addition of the inhibitors can reduce the diffusion or
migration of primary amines out of the polyurethane products by
converting the primary amines into hydroxycarboxamides or
aminocarboxamides. The relatively high molecular weight of the
reaction products, in particular when using lactones of higher
carboxylic acids, e.g. of hydroxydecanoic acid or of
hydroxydodecanoic acid, reduces diffusion or migration out of the
polyurethane matrix so that the fogging behavior is improved.
[0073] After they have been hydrolyzed, lactams and lactones also
effect an improvement in the fogging behavior of polyurethane
products by preventing diffusion of the tertiary amine catalysts
used by protonating them. Furthermore, in some applications it is
desirable to increase the crosslinking density of polyurethane
foams, in particular flexible polyurethane foams, by modification
of the formulation (increasing the proportion of crosslinker, use
of multiring MDI, increasing the index) without, however,
increasing the hardness too much at the same time. The addition of
lactones and lactams, which also function as plasticizers, makes it
possible to compensate for this undesired increase in hardness.
[0074] Examples of inhibitors which can be used according to the
present invention are the following compounds:
[0075] Lactones, for example those having a molecular weight of
from 70 to 300 g/mol, e.g. .beta.-propiolactone,
.gamma.-butyrolactone, .gamma.-valerolactone,
.epsilon.-caprolactone, .gamma.-decanolactone,
.delta.-decanolactone, .delta.-dodecanolactone,
.gamma..gamma.-dimethylbu- tyrolactone and/or
.alpha.-ethyl-.gamma.-methylbutyrolactone.
[0076] Lactams, for example those having a molecular weight of from
70 to 300 g/mol, e.g. .beta.-propiolactam, 2-pyrrolidone,
N-methylpyrrolidone and 2-piperidone.
[0077] Cyclic esters, for example those having a molecular weight
of from 150 to 500 g/mol, preferably condensation products of
aliphatic, cycloaliphatic, araliphatic and/or aromatic dicarboxylic
acids having from 4 to 15 carbon atoms and aliphatic,
cycloaliphatic, araliphatic and/or aromatic dialcohols having from
2 to 15 carbon atoms, particularly preferably condensation products
based on diethylene glycol (DEG) and adipic acid (ADA). These
cyclic esters, for example the cyclic DEG-ADA ester and the cyclic
ADA-DEG-ADA-DEG ester, are found, along with DEG and low molecular
weight linear esters, in an amount of about 40-50% by mass in a
distillation residue obtained in the synthesis of polyester polyols
based on ADA-DEG-trimethylolpropane and are accordingly
particularly economically advantageous to use.
[0078] To produce the polyisocyanate polyaddition products, the
inhibitors are preferably used in an amount of from 0.01 to 20.0%
by weight, based on the weight of the compounds which are reactive
toward isocyanates.
[0079] Furthermore, generally known .alpha.,.beta.-unsaturated
carboxylic acids, .alpha.,.beta.-unsaturated carboxylic acid
derivatives, .alpha.,.beta.-unsaturated ketones and/or
.alpha.,.beta.-unsaturated aldehydes as (vi) can advantageously be
used.
[0080] As a result of the use of (vi), any free amino groups formed
by undesired cleavage of urethane and/or urea groups are bound by
reaction with the compounds (vi) used according to the present
invention.
[0081] Both primary and secondary amines are capable of addition to
C.dbd.C double bonds, particularly if these are adjacent to a
carbonyl group. This Michael addition of the amine occurs onto the
unsaturated system in which the .pi.-electrons are delocalized over
the carbonyl group. As has been found in experiments, temperatures
of from 70 to 120.degree. C. as can be encountered under hot and
humid conditions, for example in hot steam sterilization or
cleaning with hot steam, are very surprisingly sufficient to react
at least some of the primary amine formed in the PUR foam by
hydrolytic cleavage of urethane and urea bonds with the compounds
(vi). The amino groups are bound to the .alpha.,.beta.-unsaturated
carbonyl compounds used according to the present invention by
addition onto the C.dbd.C double bonds with formation of a covalent
bond. The diffusion or migration of primary amines out of the
polyurethane foams can thus be reduced according to the present
invention. This is particularly true when the compounds (vi) are
built into the polyurethane network being formed as a result of the
presence of groups such as OH or NH.sub.2 capable of being
incorporated into the polyurethane structure. In this way, not only
are the compounds (vi) fixed and their diffusion from the
polyurethane foams is thereby prevented, but the primary amine
bound to the compound (vi) is likewise immobilized.
[0082] Preference is given to compounds (vi) which have the
following structural feature: 1
[0083] where the radicals R.sup.1 to R.sup.4 have the following
meanings:
[0084] R.sup.1: H, C.sub.1-C.sub.12-alkyl,
C.sub.6-C.sub.20-aryl,
[0085] R.sup.2: H, C.sub.1-C.sub.12-alkyl,
C.sub.6-C.sub.20-aryl,
[0086] R.sup.3: H, C.sub.1-C.sub.12-alkyl,
C.sub.6-C.sub.20-aryl,
[0087] R.sup.4: H, C.sub.1-C.sub.12-alkyl, C.sub.6-C.sub.20-aryl,
--O--C.sub.1-C.sub.12-alkyl, --O--C.sub.1-C.sub.12-alkyl-OH,
--C.sub.1-C.sub.12-alkyl-OH, --O--C.sub.1-C.sub.12-alkyl,
--C.sub.1-C.sub.12-alkyl-NH.sub.2,
--O--C.sub.1-C.sub.12-alkyl-NH.sub.2, --O-benzyl, --O-aryl,
--O--C.sub.1-C.sub.12-alkyl-COOH,
--O--C.sub.1-C.sub.12-alkyl-CH(OH)--CH.sub.2--O-- (CO)--CHCH.sub.2,
--O--C.sub.1-C.sub.12-alkyl-O--(CO)--CHCH.sub.2.
[0088] As (vi), particular preference is given to the following
compounds: acrylic acid, crotonic acid, isocrotonic acid, sorbic
acid, fumaric acid, cinnamic acid, hydroxyethyl acrylate,
3-(acryloyloxy)-2-hydroxypropyl methacrylate, benzyl cinnamate,
trans-3-nonen-2-one, benzalacetone, dibenzalacetone,
benzalacetophenone, 1-methylbenzalacetophenone, crotonaldehyde,
cinnamaldehyde, methyl vinyl ketone and/or
.alpha.,.beta.-unsaturated polyester diols prepared by
polycondensation of maleic acid, fumaric acid and/or acrylic acid
with oligomeric diols such as butanediol, diethylene glycol,
propylene glycol, 1,3-propanediol and/or triols such as glycerol
and having a molecular weight factor per double bond of from 150 to
3000, a functionality of from 2 to 6, a hydroxyl number of from 20
to 800 mg KOH/g and an acid number of from 0 to 15.
[0089] In particular, the following compounds are used as (vi):
hydroxyethyl acrylate, 3-(acryloyloxy)-2-hydroxypropylmethacrylate,
trans-3-nonen-2-one, benzyl cinnamate, crotonic acid and/or
.alpha.,.beta.-unsaturated polyester diols (A) prepared by
polycondensation of maleic acid, fumaric acid or acrylic acid with
oligomeric diols such as butanediol, diethylene glycol, propylene
glycol, 1,3-propanediol and/or triols such as glycerol and having a
molecular weight factor per double bond of from 150 to 3000, a
functionality of from 2 to 6, a hydroxyl number of from 20 to 800
mg KOH/g and an acid number of from 0 to 15.
[0090] .alpha.,.beta.-unsaturated carbonyl compounds having
additional functional groups such as OH and NH.sub.2 which are
built into the PUR network lead to a particularly significant
reduction in the MDA and TDA contents. Examples which may be
mentioned are hydroxyethyl acrylate and
3-(acryloyloxy)-2-hydroxypropyl methacrylate. Polyols containing
integrated C.dbd.C double bonds conjugated with the carbonyl group
act in a similar way.
[0091] In general, particular preference is given to compounds (vi)
which dissolve readily in the isocyanates or the compounds which
are reactive toward isocyanates. The compounds (vi) are preferably
used in admixture with the isocyanates.
[0092] In the process of the present invention for producing
polyurethane foams, (vi) is preferably used in an amount of from
0.1 to 20% by weight, particularly preferably from 0.5 to 10% by
weight, based on the weight of the polyisocyanate polyaddition
products.
[0093] The polyurethane foams obtainable according to the present
invention have the particular advantage that any primary amines, in
particular primary aromatic amines, formed by hydrolysis are
converted into an unproblematical form by means of the compounds
(vi). The polyurethane foams, in particular mattresses, furniture
upholstery or foam backing for carpets, thus particularly
preferably contain products of the reaction of primary and/or
secondary amines, preferably aromatic amines, with the
abovementioned compounds (vi), i.e. the .alpha.,.beta.-unsaturated
carboxylic acids, .alpha.,.beta.-unsaturated carboxylic acid
derivatives, .alpha.,.beta.-unsaturated ketones and/or
.alpha.,.beta.-unsaturated aldehydes.
[0094] The compounds described above, i.e. the hydrophobic
compounds and also (i) organic, cyclic compounds having a molecular
weight of from 200 to 3000 g/mol, (ii) salts of metals of
transition groups I, II and/or VIII, (iii) organic and/or inorganic
acid anhydrides, (iv) cyclic sulfonic esters and/or sulfones, (v)
lactones, lactams and/or cyclic esters and/or (vi)
.alpha.,.beta.-unsaturated carboxylic acids,
.alpha.,.beta.-unsaturated carboxylic acid derivatives,
.alpha.,.beta.-unsaturated ketones and/or
.alpha.,.beta.-unsaturated aldehydes, can be used for producing
polyisocyanate polyaddition products by generally known methods,
for example by reacting isocyanates with compounds which are
reactive toward isocyanates in the presence or absence of
catalysts, blowing agents, additives and/or auxiliaries. For
example, compact or cellular, for example microcellular, flexible,
semirigid or rigid polyurethane foams, thermoplastic polyurethanes
or polyurethane elastomers can be produced as polyisocyanate
polyaddition products by customary methods using the inhibitors
employed according to the present invention. The compounds
described are preferably used in processes for producing
polyurethane elastomers or foamed polyisocyanate polyaddition
products, in particular flexible polyurethane foams having a
density of from 15 to 300 kg/m.sup.3, preferably from 2 to 70
kg/m.sup.3, preferably mattresses and/or furniture upholstery or
carpet backing, in particular hospital mattresses, by reacting
isocyanates with compounds which are reactive toward isocyanates in
the presence of catalysts, blowing agents and, if desired,
additives and/or auxiliaries. These products, i.e. in particular
the furniture upholstery and/or carpet backing or the mattresses,
are increasingly treated with hot steam for the purpose of cleaning
or disinfection, so that it is precisely these products in which
the advantages obtained according to the present invention are
particularly pronounced.
[0095] The generally customary starting materials for producing the
polyisocyanate polyaddition products are described below by way of
example.
[0096] As isocyanates, it is possible to use the aliphatic,
cycloaliphatic, araliphatic and preferably aromatic organic
isocyanates known per se, preferably polyfunctional isocyanates,
particularly preferably diisocyanates.
[0097] Specific examples are: alkylene diisocyanates having from 4
to 12 carbon atoms in the alkylene radical, e.g. dodecane
1,12-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 mixtures of these isomers,
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane
(isophorone diisocyanate), hexahydrotolylene 2,4- and
2,6-diisocyanate and also the corresponding isomer mixtures,
dicyclohexylmethane 4,4'-, 2,2'- and 2,4'-diisocyanate and also the
corresponding isomer mixtures, aromatic diisocyanates and
polyisocyanates, e.g. tolylene 2,4- and 2,6-diisocyanate (TDI) and
the corresponding isomer mixtures, diphenylmethane 4,4'-, 2,4'- and
2,2'-diisocyanate (MDI) and the corresponding isomer mixtures,
naphthalene 1,5-diisocyanate (NDI), mixtures of diphenylmethane
4,4'- and 2,4'-diisocyanates, mixtures of NDI and diphenylmethane
4,4'- and/or 2,4'-diisocyanates,
3,3'-dimethyl-4,4'-diisocyanatobiphenyl (TODI), mixtures of TODI
and diphenylmethane 4,4'- and/or 2,4'-diisocyanates,
polyphenylpolymethylene polyisocyanates, mixtures of
diphenylmethane 4,4'-, 2,4'- and 2,2'-diisocyanates and
polyphenylpolymethylene polyisocyanates (crude MDI) and mixtures of
crude MDI and tolylene diisocyanates. The organic diisocyanates and
polyisocyanates can be used individually or in the form of their
mixtures.
[0098] Use is frequently also made of modified polyfunctional
isocyanates, i.e. products which are obtained by chemical reaction
of organic diisocyanates and/or polyisocyanates. Examples which may
be mentioned are diisocyanates and/or polyisocyanates containing
ester, urea, biuret, allophanate, carbodiimide, isocyanurate,
uretdione and/or urethane groups specific examples of suitable
modified isocyanates are: organic, preferably aromatic
polyisocyanates containing urethane groups and having NCO contents
of from 33.6 to 15% by weight, preferably from 31 to 21% by weight,
based on the total weight, modified diphenylmethane
4,4'-diisocyanate, modified diphenylmethane 4,4'- and
2,4'-diisocyanate mixtures, modified NDI, modified TODI, modified
crude MDI and/or tolylene 2,4- or 2,6-diisocyanate, with examples
of dialkylene glycols or polyoxyalkylene glycols which can be used
individually or as mixtures being: diethylene glycol, dipropylene
glycol, polyoxyethylene, polyoxypropylene and
polyoxypropylene-polyoxyethylene glycols, triols and/or tetrols.
Also suitable are prepolymers containing NCO groups, having NCO
contents of from 25 to 3.5% by weight, preferably from 21 to 14% by
weight, based on the total weight, and prepared from, for example,
polyester polyols and/or preferably polyether polyols and
diphenylmethane 4,4'-diisocyanate, mixtures of diphenylmethane
2,4'- and 4,4'-diisocyanate, NDI, TODI, mixtures of NDI and isomers
of MDI, tolylene 2,4- and/or 2,6-diisocyanates or crude MDI.
Further modified isocyanates which have been found to be useful are
liquid polyisocyanates containing carbodiimide groups and/or
isocyanurate rings and having NCO contents of from 33.6 to 15% by
weight, preferably from 31 to 21% by weight, based on the total
weight, e.g. ones based on diphenylmethane 4,4'-, 2,4'- and/or
2,2'-diisocyanate, NDI, TODI and/or tolylene 2,4'- and/or
2,6-diisocyanate.
[0099] The modified polyisocyanates may, if desired, be mixed with
one another or with unmodified organic polyisocyanates such as
diphenylmethane 2,4'- and/or 4,4'-diisocyanate, NDI, TODI, crude
MDI and tolylene 2,4- and/or 2,6-diisocyanate.
[0100] Isocyanates which are preferably used in the mixtures
employed according to the present invention or the process of the
present invention are diphenylmethane 4,4'-, 2,4'- and/or
2,2'-diisocyanate, tolylene 2,4- and/or 2,6-diisocyanate, NDI,
hexamethylene diisocyanate and/or isophorone diisocyanate, with
these isocyanates being able to be used in any mixtures or in
modified form as described above.
[0101] As isocyanate-reactive compounds, if desired in addition to
the hydrophobic compounds used according to the present invention,
insofar as the latter are reactive toward isocyanates, usually
having at least two reactive hydrogen atoms, usually hydroxyl
and/or amino groups, use can advantageously be made of those having
a functionality of from 2 to 8, preferably from 2 to 6, and a
molecular weight of usually from 60 to 10000. Compounds which have
been found to be useful are, for example, polyetherpolyamines
and/or preferably polyols selected from the group consisting of
polyether polyols, polyester polyols, polythioether polyols,
polyesteramides, hydroxyl-containing polyacetals and
hydroxyl-containing aliphatic polycarbonates or mixtures of at
least two of the polyols mentioned. Preference is given to using
polyester polyols and/or polyether polyols which can be prepared by
known methods.
[0102] The polyester polyols preferably have a functionality of
from 2 to 4, in particular from 2 to 3, and a molecular weight of
usually from 500 to 3000 g/mol, preferably from 1200 to 3000 g/mol
and in particular from 1800 to 2500 g/mol.
[0103] The polyether polyols have a functionality of preferably
from 2 to 6 and usually have molecular weights of from 500 to
8000.
[0104] Suitable polyether polyols also include, for example,
polymer-modified polyether polyols, preferably graft polyether
polyols, in particular those based on styrene and/or acrylonitrile
which can be prepared by in situ polymerization of acrylonitrile,
styrene or preferably mixtures of styrene and acrylonitrile.
[0105] Like the polyester polyols, the polyether polyols can be
used individually or in the form of mixtures. They can also be
mixed with the graft polyether polyols or polyester polyols or with
hydroxyl-containing polyesteramides, polyacetals and/or
polycarbonates.
[0106] Polyol components used for rigid polyurethane foams which
may contain isocyanurate structures are high-functionality polyols,
in particular polyether polyols based on high-functionality
alcohols, sugar alcohols and/or saccharides as initiator molecules
while polyols used for flexible foams are 2- and/or 3-functional
polyether polyols and/or polyester polyols based on glycerol and/or
trimethylolpropane and/or glycols as initiator molecules or
alcohols to be esterified. The polyether polyols are prepared using
a known technology. Suitable alkylene oxides for preparing the
polyols 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. Preference
is given to using alkylene oxides which lead to primary hydroxyl
groups in the polyol. Particular preference is given to using
polyols which have been alkoxylated using ethylene oxide at the
conclusion of the alkoxylation and therefore have primary hydroxyl
groups. For producing thermoplastic polyurethanes, preference is
given to using polyols having a functionality of from 2 to 2.2 and
no crosslinker.
[0107] As compounds which are reactive toward isocyanates, it is
also possible to use chain extenders and/or crosslinkers. The
addition of chain extenders, crosslinkers or, if desired, mixtures
thereof can prove to be advantageous for, for example, modifying
the mechanical properties, e.g. the hardness, of the polyisocyanate
polyaddition products produced using these substances. Chain
extenders and/or crosslinkers which can be used are water, diols
and/or triols having molecular weights of from 60 to <500,
preferably from 60 to 300. Examples of suitable chain
extenders/crosslinkers are aliphatic, cycloaliphatic and/or
araliphatic diols having from 2 to 14, preferably from 4 to 10,
carbon atoms, for example ethylene glycol, 1,3-propanediol,
1,10-decanediol, o-, m-, p-dihydroxycyclohexane, diethylene glycol,
dipropylene glycol and preferably 1,4-butanediol, 1,6-hexanediol
and bis(2-hydroxyethyl)hydroqui- none, triols such as 1,2,4- or
1,3,5-trihydroxycyclohexane, glycerol and trimethylolpropane and
low molecular weight hydroxyl-containing polyalkylene oxides based
on ethylene oxide and/or 1,2-propylene oxide and diols and/or
triols as initiator molecules.
[0108] If chain extenders, crosslinkers or mixtures thereof are
employed for producing the polyisocyanate polyaddition products,
they are advantageously used in an amount of from 0 to 20% by
weight, preferably from 2 to 8% by weight, based on the weight of
the compounds which are reactive toward isocyanates; thermoplastic
polyurethanes are preferably produced without a crosslinker.
[0109] Suitable catalysts are generally customary compounds, for
example organic amines such as triethylamine, triethylenediamine,
tributylamine, dimethylbenzylamine,
N,N,N',N'-tetramethylethylenediamine,
N,N,N',N'-tetramethylbutanediamine,
N,N,N',N'-tetramethylhexane-1,6-diami- ne, dimethylcyclohexylamine,
pentamethyldipropylenetriamine, pentamethyldiethylenetriamine,
3-methyl-6-dimethylamino-3-azapentol, dimethylaminopropylamine,
1,3-bis(dimethylamino)butane, bis(2-dimethylaminoethyl) ether,
N-ethylmorpholine, N-methylmorpholine, N-cyclohexylmorpholine,
2-dimethylaminoethoxyethanol, dimethylethanolamine,
tetramethylhexamethylenediamine,
dimethylamino-N-methylethanolamine, N-methylimidazole,
N-(3-aminopropyl)imidazole, N-(3-aminopropyl)-2-methylimidazole,
1-(2-hydroxyethyl)imidazole, N-formyl-N,N'-dimethylbutylenediamine,
N-dimethylaminoethylmorpholine,
3,3'-bis(dimethylamino)-di-n-propylamine and/or
2,2'-bis(2-piperazinoisopropyl) ether, dimethylpiperazine, N,N'-bis
(3-aminopropyl) ethylenediamine and/or tris(N,N-dimethylaminopro-
pyl)-s-hexahydrotriazine, or mixtures comprising at least two of
the amines mentioned. Also possible are relatively high molecular
weight tertiary amines as are described, for example, in DE-A 28 12
256. Further catalysts which can be used for this purpose are
customary organic metal compounds, preferably organic tin compounds
such as tin(II) salts of organic carboxylic acids, e.g. tin(II)
acetate, tin(II) octoate, tin(II) ethylhexanoate and tin(II)
laurate and the dialkyltin(IV) salts of organic carboxylic acids,
e.g. dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate
and dioctyltin diacetate. Tertiary aliphatic and/or cycloaliphatic
amines are preferably present in the mixtures, particularly
preferably triethylenediamine.
[0110] As blowing agents, it is possible to use, if desired,
preferably for producing foamed polyurethanes, generally known
blowing agents such as materials which have a boiling point at
atmospheric pressure in the range from -40.degree. C. to
120.degree. C., gases and/or solid blowing agents and/or water in
customary amounts, for example carbon dioxide, alkanes and/or
cycloalkanes, e.g. isobutane, propane, n- or iso-butane, n-pentane
and cyclopentane, ethers such as diethyl ether, methyl isobutyl
ether and dimethyl ether, nitrogen, oxygen, helium, argon, nitrous
oxide, halogenated hydrocarbons and/or partially halogenated
hydrocarbons, e.g. trifluoromethane, monochlorotrifluoroethane,
difluoroethane, pentafluoroethane or tetrafluoroethane, or mixtures
comprising at least two of the blowing agents mentioned by way of
example.
[0111] Examples of auxiliaries and/or additives are surface-active
substances, foam stabilizers, cell regulators, fillers, dyes,
pigments, flame retardants, hydrolysis inhibitors, fungistatic and
bacteriostatic substances.
[0112] The organic polyisocyanates and the isocyanate-reactive
compounds having a molecular weight of from 60 to 10000 g/mol are
usually reacted in such amounts that the equivalence ratio of NCO
groups of the polyisocyanates to the sum of the reactive hydrogen
atoms of the isocyanate-reactive compounds is 0.5-5:1, preferably
0.9-3:1 and in particular 0.95-2:1.
[0113] It may be advantageous for the polyurethanes to contain at
least some bound isocyanurate groups. In these cases, the ratio of
NCO groups of the polyisocyanates to the sum of the reactive
hydrogen atoms is advantageously 1.5-60:1, preferably 1.5-8:1.
[0114] The polyisocyanate polyaddition products can, for example,
be produced by the one-shot method or the known prepolymer method,
for example with the aid of the high-pressure or low-pressure
technique in open or closed molds, reaction extruders or belt
units.
[0115] The mixtures used according to the present invention are
preferably employed for producing foamed polyisocyanate
polyaddition products, for example foamed polyurethanes and/or
polyisocyanurates.
[0116] It has been found to be advantageous to produce the
polyisocyanate polyaddition products by the two-component process
and to combine the compounds which are reactive toward isocyanates
and, if desired, the catalysts, blowing agents and/or auxiliaries
and/or additives as the A component and to use the isocyanates and
catalysts and/or blowing agents as the B component. The hydrophobic
compounds can, if they have no groups which are reactive toward
isocyanates, be used in the A and/or B component or in the
constituents of these components. Hydrophobic compounds which have
groups which are reactive toward isocyanates, for example hydroxyl
groups, are preferably used in the polyol component.
[0117] The invention is illustrated by the following examples.
EXAMPLES
[0118] In order to simulate conditions as can occur in the
abovementioned specific applications, aging under hot and humid
conditions was carried out on specimens of the flexible foams
mentioned below. For this purpose, test cubes having an edge length
of 3 cm were aged at 90.degree. C. and 90% relative atmospheric
humidity for 72 hours in an air conditioned chamber. Under these
conditions, hydrolytic cleavage of urethane and urea bonds and thus
the formation of aromatic amines can occur. The amine formed was
subsequently extracted by means of a method developed by Prof.
Skarping, University of Lund. For this purpose, the foam is
squeezed out 10 times with 10 ml of acetic acid (w=1% by weight).
The acetic acid was, with the foam specimen compressed, transferred
to a 50 ml volumetric flask. The process was repeated three times
and the volumetric flask was made up to the mark with acetic
acid.
[0119] The MDA content of the combined extracts was subsequently
determined by means of capillary electrophoresis with UV detection.
The MDA and TDA contents reported in the tables correspond to the
absolute contents of MDA and TDA formed in the PUR foam.
[0120] 1) Flexible polyurethane foam, hereinafter referred to as
Comparative System 1, produced by mixing 750 g of A component with
354 g of B component (index: 90) and transferring the foaming
mixture into an aluminum mold (40.times.40.times.10 cm) heated to
53.degree. C., with the components having the following
compositions:
[0121] A Component
1 97 parts by weight of a polyol having an OHN of 28, a mean
functionality of 2.3 and an EO/PO ratio of 14/86, 3 parts by weight
of a polyol having an OHN of 42, a mean functionality of 3 and a
PO/EO ratio of 30/70, 3.31 parts by weight of water, 0.8 part by
weight of aminopropylimidazole, 0.6 part by weight of Lupragen
.RTM. N107, OHN: '421 (BASF Aktiengesellschaft), 0.5 part by weight
of Tegostab .RTM. B 8631 (Goldschmidt)
[0122] B Component
[0123] Mixture of 50% of a polymeric MDI and 50% of a 1:1 mixture
of 2,4'-MDI and 4,4'-MDI.
[0124] This system includes aminopropylimidazole and
2-(2-dimethylaminoethoxy)ethanol as catalysts which can be built
into the polyurethane structure. It was selected to demonstrate the
particular effectiveness of the additives in PUR formulations
containing catalysts and catalytically active spacer polyols which
can be built into the PUR network.
[0125] 2) Flexible polyurethane foam (index: 90), hereinafter
referred to as Comparative System 2, which was employed as a model
for standard flexible foams, produced by mixing 750 g of A
component with 354 g of B component (index: 90) and transferring
the foaming mixture into an aluminum mold (40.times.40.times.10 cm)
heated to 53.degree. C., with the components having the following
compositions:
[0126] A Component
2 97 parts by weight of a polyol having an OHN of 28, a mean
functionality of 2.3 and an EO/PO ratio of 14/86, 3 parts by weight
of a polyol having an OHN of 42, a mean functionality of 3 and a
PO/EO ratio of 30/70, 3.31 parts by weight of water, 0.22 part by
weight of 1,4-diazabicyclo[2.2.2]- octane, 0.14 part by weight of
Lupragen .RTM. N 206 (BASF Aktiengesellschaft), 0.5 part by weight
of Tegostab .RTM. B 8631 (Goldschmidt)
[0127] B Component
[0128] Mixture of 50% of a polymeric MDI and 50% of a 1:1 mixture
of 2,4'-MDI and 4,4'-MDI.
[0129] 3) Flexible polyurethane foam (index: 90), hereinafter
referred to as Comparative System 3, produced from:
[0130] A Component
3 100 parts by weight of a polyol having an OHN of 35, a mean
functionality of 3.0 and an EO/PO ratio of 13.3/86.4, 3.31 parts by
weight of water, 0.35 part by weight of Lupragen .RTM. N 201
(BASF), 0.38 part by weight of tin dioctoate, 1.0 part by weight of
Tegostab .RTM. B 8680 (Goldschmidt)
[0131] B Component:
[0132] Mixture of 50% of a polymeric MDI and 50% of a 1:1 mixture
of 2,4'-MDI and 4,4'-MDI.
[0133] 4) Flexible polyurethane foam (index: 90), hereinafter
referred to as Comparative System 4, produced by mixing 750 g of A
component with 275 g of B component (index: 115) and transferring
the foaming mixture to an open mold having a capacity of 40 l, with
the components having the following compositions:
[0134] A Component
4 100 parts by weight of Lupranol .RTM. 2080 (BASF
Aktiengesellschaft), 4.50 parts by weight of water, 0.30 part by
weight of Dabco .RTM. 33LV (Air Products), 0.20 part by weight of
tin dioctoate, 1.00 part by weight of silicone stabilizer BF
2370
[0135] B Component
[0136] Lupranat.RTM. T 80 (BASF Aktiengesellschaft)
[0137] 5) Flexible polyurethane foam (index: 90), hereinafter
referred to as Comparative System 5, produced from:
[0138] A Component
5 100 parts of Lupranol .RTM. 2080 (BASF Aktiengesellschaft), 3.80
parts of water 0.15 part of Dabco .RTM. 33LV (Air Products), 0.26
part of tin dioctoate, 0.05 part of Niax .RTM. A1 (OSI), 1.00 part
of silicone stabilizer BF 2370
[0139] B Component
[0140] Lupranat.RTM. T 80 (BASF Aktiengesellschaft)
[0141] In Table 1, the chemical and physical properties of the
hydrophobic compounds used are compared.
6TABLE 1 Chemical and physical properties of the hydrophobic
compounds OH number [mg Viscosity Oxirane content Hydrophobic
compound KOH/g] [mPas] [%] 1 (Kraton liquid 33 50000 0.00 polymer L
2203) 2 (Merginat PV 235) 250-300 1200-2000 2.59 3 (Merginat PV
300) 85 2990 1.77 4 (Sovermol 1137/05) 50-80 10000-14000 0.00 5 61
955 6 80 565
[0142] Chemical nature of the hydrophobic compounds:
[0143] 1: Hydroxy-functionalized polyethylene-polybutylene,
Shell
[0144] 2: Branched oleochemical polyol, HOBUM
[0145] 3: Branched oleochemical polyol, HOBUM
[0146] 4: Slightly branched fat-chemical polyester, Henkel
[0147] 5: Polyester polyol based on ADA/Pripol 1017
(Unichema)/DEG/TMP, where Pripol 1017 (BASF Aktiengesellschaft) is
a dimeric fatty acid ester and is present in 5 in an amount of
about 10%
[0148] 6: Polyether polyol based on castor oil/PO, BASF
Aktiengesellschaft
[0149] ADA: Adipic acid
[0150] PO: Propylene oxide
[0151] DEG: Diethylene glycol
[0152] TMP: Trimethylolpropane
7TABLE 2 Summary of Examples 1 to 15 Amount of Hydrophobic
hydrophobic compound Comparative compound [% by weight in A Example
System added component] 1 1 -- -- 2 1 2 1 3 1 2 2 4 1 2 5 5 1 2 11
6 1 4 11 7 1 3 11 8 2 -- -- 9 2 2 11 10 3 -- -- 11 3 1 10 12 4 --
-- 13 4 5 30 14 5 -- -- 15 5 6 100
[0153] Comparative Systems 1 to 5 were produced with and without
addition of the hydrophobic compounds listed in Table 1.
[0154] In the Examples summarized in Table 2, the proportion in %
by weight indicated in the table of the base polyol of the
respective A component described under 1) to 5) was in each case
replaced by a hydrophobic compound having at least two groups which
are reactive toward isocyanates or a mixture of hydrophobic
compounds having at least two groups which are reactive toward
isocyanates.
[0155] Table 3 compares the MDA or TDA contents of Examples 1 to 15
with and without addition of hydrophobic compounds which in each
case have at least two groups which are reactive toward
isocyanates.
8TABLE 3 Comparison of the MDA contents of flexible PUR foams with
and without addition of hydrophobic compounds having at least two
groups which are reactive toward isocyanates 4,4'-MDA 2,4'-MDA
4,4'-MDA 2,4'-MDA Cream time Gel time Rise time [ppm] [ppm] [ppm]
[ppm] Example [s] [s] [s] w.o.a. w.o.a. w.a. w.a. 1 13 80 100 <1
<1 397 687 2 20 75 110 <1 <1 139 275 3 20 80 115 <1
<1 109 225 4 20 80 115 <1 <1 90 94 5 12 75 105 <1 <1
56 141 6 15 90 105 <1 <1 87 200 7 15 85 135 <1 <1 96
207 8 13 45 80 <1 <1 32 78 9 13 55 95 <1 <1 24 66 10 15
95 130 <1 <1 53 153 11 25 150 180 <1 <1 11 27 12 -- --
-- <1 <1 69 35 13 -- -- -- <1 <1 24 15 14 -- -- --
<1 <1 69 35 15 -- -- -- <1 <1 17 9 w.o.a.: Extraction
after processing of the foam w.a.: Extraction after hot-humid aging
for 3 days at 90.degree. C. and 90% relative atmospheric humidity
in an air conditioned chamber
[0156] Table 4 presents examples in which further compounds from
the group consisting of (i), (ii), (iii), (iv), (v) and (vi) which
are capable of further reducing the primary amine content were
added in addition to the hydrophobic compounds to the polyurethane
foam formulations. Table 5 shows the corresponding results.
9TABLE 4 Foams produced by addition of 2 parts of the hydrophobic
compound 2 and a further compound from the group consisting of (i),
(ii), (iii), (iv), (v) and (vi) for reducing the primary amine
content Amount of additive Comparative [% by weight dissolved
Example System Additive added in A component] 16 1 Lupragen VP 9198
10 17 1 1-naphthol-8- 2 sulfonic sultone
[0157] Lupragen.RTM. VP 9198 (BASF Aktiengesellschaft):
.alpha.,.beta.-unsaturated polyester diol having an OH number of
336 mg KOH/g, an acid number of 0.7 and a molecular weight factor
per double bond of 262, prepared by polycondensation of maleic
anhydride, 1,3-propanediol and diethylene glycol in a molar ratio
of 1:1:1.
10TABLE 5 Results of Examples 16 and 17 4,4'-MDA 2,4'-MDA 4,4'-MDA
2,4'-MDA Cream time Gel time Rise time [ppm] [ppm] [ppm] [ppm]
Example [s] [s] [s] w.o.a. w.o.a. w.a. w.a. 16 21 117 150 <1
<1 33 82 17 14 83 -- <1 <1 33 89 w.o.a.: Extraction after
processing of the foam w.a.: Extraction after hot-humid aging for 3
days at 90.degree. C. and 90% relative atmospheric humidity in an
air conditioned chamber
[0158] The detection limit of the capillary electrophoretic
determination is 1 ppm.
[0159] As the MDA and TDA contents in Examples 1 to 12 show, the
advantages obtained according to the present invention, i.e. the
significantly reduced content of primary aromatic amines after
aging under hot and humid conditions due to the addition of
hydrophobic compounds, were able to be demonstrated convincingly.
The reduced content of aromatic amines is based on their formation
being prevented by the addition of the hydrophobic compounds
reducing the penetration of moisture into the interior of the foam
and thus countering hydrolytic cleavage of urethane and urea
bonds.
* * * * *