U.S. patent application number 14/065974 was filed with the patent office on 2014-02-27 for use of metal salts of a carboxylic acid in the production of polyurethane systems.
This patent application is currently assigned to EVONIK GOLDSCHMIDT GMBH. The applicant listed for this patent is EVONIK GOLDSCHMIDT GMBH. Invention is credited to Roland Hubel, Sarah Schmitz.
Application Number | 20140058004 14/065974 |
Document ID | / |
Family ID | 42537792 |
Filed Date | 2014-02-27 |
United States Patent
Application |
20140058004 |
Kind Code |
A1 |
Schmitz; Sarah ; et
al. |
February 27, 2014 |
USE OF METAL SALTS OF A CARBOXYLIC ACID IN THE PRODUCTION OF
POLYURETHANE SYSTEMS
Abstract
A catalyst system which is suitable for catalyzing the
production of polyurethane systems is provided. The catalyst system
contains a metal salt of a carboxylic acid to whose carbonyl carbon
a hydrogen atom or a hydrocarbon radical is bound, with the proviso
that the carboxylic acid does not have exclusively a single ethyl
or n-propyl branch in the 2 position.
Inventors: |
Schmitz; Sarah; (Essen,
DE) ; Hubel; Roland; (Essen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EVONIK GOLDSCHMIDT GMBH |
Essen |
|
DE |
|
|
Assignee: |
EVONIK GOLDSCHMIDT GMBH
Essen
DE
|
Family ID: |
42537792 |
Appl. No.: |
14/065974 |
Filed: |
October 29, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12836155 |
Jul 14, 2010 |
|
|
|
14065974 |
|
|
|
|
Current U.S.
Class: |
521/127 ;
521/126; 524/590; 528/58 |
Current CPC
Class: |
C08G 2101/0008 20130101;
C08G 2101/0083 20130101; C08G 18/244 20130101; C08G 18/7621
20130101; C08G 2101/005 20130101; C08G 18/1816 20130101; C08L 75/08
20130101; C08G 18/4833 20130101 |
Class at
Publication: |
521/127 ; 528/58;
524/590; 521/126 |
International
Class: |
C08G 18/24 20060101
C08G018/24; C08L 75/08 20060101 C08L075/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 18, 2009 |
DE |
10 2009 033 710.5 |
Claims
1. A polyurethane system comprising at least one organic isocyanate
and at least one polyol, wherein said organic isocyanate has at
least two isocyanate functions and said polyol has at least two
groups reactive with isocyanate, admixed with a metal salt of a
carboxylic acid bound by its carbonyl carbon to a saturated
hydrocarbon group containing 8 to 13 carbon atoms, wherein said
saturated hydrocarbon group is either an unbranched alkyl radical
or has only methyl group branches.
2. The polyurethane system according claim 1, further comprising at
least one organic solvent.
3. The polyurethane system according to claim 2, wherein said
organic solvent is an organic aprotic solvent.
4. The polyurethane system according to claim 1, wherein the metal
in said metal salt is selected from Groups Ia, IIa, IVa, Va, Ib,
IIb, and VIIIb of the Periodic Table of the Elements.
5. The polyurethane system according to claim 1, wherein the metal
in said metal salt is selected from Na, K, Mg, Ca, Sn, Pb, Bi, Zn,
Cu, Fe, Co and Ni.
6. The polyurethane system according to claim 1, wherein the metal
in said metal salt is Sn.
7. The polyurethane system according to claim 1, wherein the
polyurethane system is a polyurethane coating, a polyurethane
adhesive, a polyurethane sealant, a polyurethane elastomer, a rigid
polyurethane foam, a flexible polyurethane foam, a viscoelastic
foam, an HR foam, a semirigid polyurethane foam, a thermoformable
polyurethane foam, or an integral foam.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present application a divisional of co-pending
application having U.S. Ser. No. 12/836,155, filed on Jul. 14,
2010, which claims priority of German Patent Application No. 10
2009 033 710.5, filed on Jul. 18, 2009, the contents of all of
which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to the use of metal salts of
carboxylic acids, in particular 3,5,5-trimethylhexanoic acid and
n-octanoic acid, and solutions thereof in the production of
polyurethane systems (PUR systems).
BACKGROUND
[0003] Polyurethane systems include, for example, polyurethane
coatings, polyurethane adhesives, polyurethane sealants,
polyurethane elastomers or polyurethane foams.
[0004] Owing to their excellent mechanical and physical properties,
polyurethane foams are used in a wide variety of fields. A
particularly important market for various types of PUR foams, e.g.,
conventional flexible foams based on ether polyols and ester
polyols, high-resilience foams (frequently referred to as HR
foams), rigid foams, integral foams and microcellular foams, and
also foams whose properties lie between these classifications,
e.g., semirigid systems, is the automobile industry and the
furniture industry. For example, rigid foams are used as roof
lining, ester foams are used for interior cladding of doors and for
stamped-out sun visors, while high-resilience foams and flexible
foams are used for seat systems and mattresses.
[0005] Catalysts suitable for one-component moisture-reactive
polyurethane compositions typically contain tin compounds such as
tin carboxylates, in particular tin octoate (corresponds to tin
2-ethylhexanoate), frequently combined with tertiary amines.
[0006] The use of tin octoate in the production of flexible PUR
foams based on polyetherols is described, for example, in Steve
Lee, Huntsman Polyurethanes, The Polyurethanes Book, Verlag Wiley,
pp. 140, 143-144, and Ron Herrington, Flexible Polyurethane Foams,
Dow Chemical, pp. 2.30. The tin octoate serves as a catalyst for
the reaction of isocyanates with polyols (also referred to as a
gelling catalyst) via a complex transition state. During production
of the foam, the tin octoate hydrolyses and liberates both the salt
of 2-ethylhexanoic acid and also the acid itself. The decomposition
is desirable because the backreaction of urethane formation to
reform the starting materials is suppressed, but it should not,
where possible, lead to liberation of possibly toxicologically
problematical substances. The patent literature, too, contains
numerous patent applications which describe the use of said tin
octoate, e.g., see BE 779607, GB 1432281, GB 1422056, GB 1382538,
GB 1012653, GB 982280. In these documents, catalyst systems
comprising tin octoate are preferably used.
[0007] However, such tin catalysts have recently been coming under
increasing pressure from users because of toxicological concerns
regarding the starting materials, in particular the ligands, used
for producing them. There is therefore an increasing need for less
toxicologically problematical alternatives.
[0008] To meet the requirements, which have become significantly
more demanding in recent years, in which the automobile and
furniture industries and their foam suppliers have to meet in
respect of emission and toxicity specifications, catalyst systems
that contain less toxic ligands which can be polymerized into the
foam have been developed. Such systems are described, for example,
in EP 1013704. The disadvantage of these systems is the higher
amounts needed and the associated costs because of the lower tin
content and the strong shielding of the active tin by the ligands.
The systems have to date been one of the few alternatives to the
widespread tin octoate catalyst system (tin(II) salt of
2-ethylhexanoic acid) or organotin compounds such as dibutyltin
dilaurate. The latter systems are to be viewed critically because
of the toxicity of the substances emitted. 2-ethylhexanoic acid,
for example, which is liberated during and after foaming gives
cause for concern because of possible damage to an unborn child
(development damage) in human beings (R 63).
[0009] Bismuth catalysts represent a further alternative to
conventional tin catalysts. Bismuth catalysts which are known for
polyurethane compositions are, for example, bismuth carboxylates,
e.g., bismuth octoate (bismuth salt of 2-ethylhexanoic acid), as
mentioned in WO 98/36007. However, the catalytic activity of
bismuth compounds in respect of the isocyanate-water reaction is
significantly lower than that of tin catalysts and the emission of
2-ethylhexanoic acid is a problem in these catalyst systems as
well.
[0010] A further disadvantage of the stated catalyst systems is
their very narrow processing latitude. It has been observed that,
in corresponding catalyst systems, a catalyst system which is
varied slightly to higher use amounts leads to very closed-celled
foams or severe shrinkage.
SUMMARY
[0011] The present invention provides a catalyst system which does
not have one or more of the abovementioned disadvantages.
[0012] Particularly, the present invention provides catalyst
systems which are suitable for catalyzing the production of
polyurethane (PU) systems and are characterized in that the
catalyst systems contain at least one metal salt of a carboxylic
acid to whose carbonyl carbon a hydrogen atom or a hydrocarbon
radical is bound, with the proviso that the carboxylic acid does
not have exclusively a single ethyl or n-propyl branch in the 2
position, (i.e., the carboxylic acid has to have at least one
further branch in the alkyl chain in any position, e.g., methyl
branches, in addition to the ethyl or n-propyl branch in the 2
position or be linear). The present invention also provides for the
use of such catalyst systems in the production of polyurethane
systems and also provides corresponding polyurethane systems, in
particular polyurethane foams and their use.
[0013] The catalyst system of the invention has the advantage that
it is suitable both for producing flexible foams based on ether
polyols and ester polyols and also for producing rigid foams and
foams whose properties lie between these classifications, e.g.,
semirigid foams.
[0014] The use of the catalyst system of the present invention
makes it possible to produce polyurethane systems using
toxicologically unproblematical starting materials which do not
emit any toxicologically problematical dissociation products even
under extreme thermal conditions. The catalyst systems of the
present invention also have the advantage that a wider processing
latitude is available in PU foam production. These advantages are
able to be achieved without adversely affecting the other physical
properties, e.g., density, hardness, rebound resilience or
compression load deflection. The compression load deflection can
even be improved by the use of the catalyst system of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The sole drawing of the present disclosure is a graph
showing the results of Example 36 of the present invention in which
the molar amount of tin in the respective catalyst system in mmol
is plotted on the X axis and the porosity in of liquid (column
liquid (FS)) of the resulting foams is plotted on the Y-axis.
DETAILED DESCRIPTION
[0016] The catalyst systems of the invention, the process for
producing the polyurethane foams, the polyurethane foams themselves
and their uses are described below by way of example without the
invention being restricted to these illustrative embodiments. Where
ranges, general formulae or classes of compounds are indicated
below, these encompass not only the respective ranges or groups of
compounds which are explicitly mentioned but also all subranges and
subgroups of compounds which can be obtained by leaving out
individual values (ranges) or compounds. Where documents are cited
in the present description, their contents, in particular with
regard to the subjects under consideration, are fully incorporated
by reference into the disclosure content of the present
invention.
[0017] The catalyst system of the invention, which is suitable for
catalyzing the production of polyurethane foams, is characterized
in that it contains a metal salt of a carboxylic acid to whose
carbonyl carbon a hydrogen atom or a hydrocarbon radical is bound,
with the proviso that the carboxylic acid does not have exclusively
a single ethyl or n-propyl branch in the 2 position. The
hydrocarbon radical is preferably selected so that the acid has at
least one carbon atom, preferably from 6 to 17 carbon atoms, more
preferably from 8 to 13 carbon atoms. The hydrocarbon radical can
be saturated or unsaturated, preferably saturated. Preference is
given to acids which do not have a branch or at least one methyl
group branch or a cycloalkyl radical being present. For the present
purposes, the expression methyl group branches refers to an
alkylcarboxylic acid whose alkyl radical is branched and which has
one or more methyl groups. Preferred catalyst systems are those
which do not comprise any carboxylic acids or salts thereof having
a single ethyl or n-propyl branch, e.g., ethylhexanoic acid. The
catalyst system preferably comprises, as metal salts, only metal
salts which are salts of carboxylic acids that are unbranched or
have exclusively methyl branches.
[0018] Catalyst systems which are preferred according to the
invention and contain at least one metal salt of a carboxylic acid
bearing methyl groups comprise one or more metal salts selected
from among the salts of n-octanoic acid, n-nonanoic acid and
3,5,5-trimethylhexanoic acid (isononanoic acid).
[0019] The metal salts are preferably salts of metals of main group
Ia, IIa, IVa or Va and of transition group Ib, IIb or VIIIb of the
Periodic Table of the Elements (CAS notation). Preferred salts are
salts of the metals Na, K, Mg, Ca, Sn, Pb, Bi, Zn, Cu, Fe, Co or
Ni, particularly preferably salts of tin.
[0020] The catalyst system can comprise exclusively the metal salts
or the metal salts in combination with a solvent, e.g., water or
one or more organic solvents. The metal salt is preferably used
alone (in undissolved form). If the metal salt is used as a
solution or in combination with a solvent, the catalyst system
preferably contains an organic aprotic solvent. If the catalyst
system contains an organic solvent, the organic solvent is
preferably selected from among polyols, esters, polyesters,
olefins, phthalates, end-capped polyethers and mineral oils. If the
metal salt is used as a solution or in combination with a solvent,
the mass ratio of metal salt to solvent is preferably from 100:1 to
1:2, more preferably from 50:1 to 1:1 and particularly preferably
from 25:1 to 2:1.
[0021] Apart from the metal salt(s) and one or more solvents, the
catalyst system can comprise further components, e.g., one or more
tertiary amines, one or more silicone stabilizers and, if
appropriate, one or more emulsifiers. However, it is preferably
present separately or as a solution.
[0022] The catalyst system of the invention can be used, in
particular, for producing polyurethane coatings, polyurethane
adhesives, polyurethane sealants, polyurethane elastomers or
polyurethane foams, preferably for producing polyurethane foams.
The catalyst system of the invention is preferably added to the
reaction mixture before or during the reaction, preferably by means
of a mixing head.
[0023] As stated above, the catalyst system can comprise further
constituents such as water, tertiary amine, silicone stabilizer
and, if appropriate, emulsifier. Such a solution of the catalyst is
frequently referred to as an activator solution. However, the
catalyst system is preferably added separately.
[0024] In the process of the invention, the direct introduction of
the catalyst system which comprises exclusively the metal salt or
salts is preferred. If this is not possible because the metal salt
has an excessively high viscosity or is a solid, the metal salts
can be introduced directly in the form of a solution. Tin isononate
and tin n-octoate (salt of n-octanoic acid) have the advantage that
concentration fluctuations do not result in a defective foam. In
contrast, the direct introduction of the viscous tin octoate (salt
of 2-ethylhexanoic acid) into the polyurethane system components,
in particular foaming components, can, owing to the only small
amounts required and the strong influence of this catalyst on the
gelling reaction, lead to problems. Since many foamers have only
direct introduction, a product which is subject to relatively small
fluctuations is of great advantage.
[0025] As an alternative to direct foaming, the catalyst system can
also be introduced in diluted from. Here, preference is given to
water-free solutions since some transition metal salts have only
limited hydrolysis stability.
[0026] The catalyst systems of the invention can be used as
catalysts in the usual formulations for producing polyurethane
systems, in particular polyurethane foams, comprising one or more
organic isocyanates having two or more isocyanate functions, one or
more polyols having two or more groups which are reactive towards
isocyanate, if appropriate further catalysts for the
isocyanate-polyol and/or isocyanate-water reactions and/or
isocyanate trimerization, water, optionally physical blowing
agents, optionally flame retardants and, if appropriate, further
additives.
[0027] Suitable isocyanates for the purposes of the present
invention are preferably all polyfunctional organic isocyanates,
for example diphenylmethane 4,4'-diisocyanate (MDI), toluene
diisocyanate (TDI), hexamethylene diisocyanate (HMDI) and
isophorone diisocyanate (IPDI). The mixture of MDI and more highly
condensed analogues having an average functionality of from 2 to 4,
which is known as "polymeric MDI" ("crude MDI"), and also the
various isomers of TDI in pure form or as an isomer mixture are
particularly suitable.
[0028] Suitable polyols for the purpose of the present invention
are preferably all organic substances having a plurality of groups
which are reactive towards isocyanates, and also preparations
thereof. Preferred polyols are all polyether polyols and polyester
polyols which are customarily used for producing polyurethane
systems, in particular polyurethane foams. Polyether polyols are
obtained by reacting polyfunctional alcohols or amines with
alkylene oxides. Polyester polyols are based on esters of polybasic
carboxylic acids (which can be either aliphatic, for example adipic
acid, or aromatic, for example phthalic acid or terephthalic acid)
with polyhydric alcohols (usually glycols). In addition, polyethers
based on natural oils (natural oil based polyols, NOPs) can also be
used. These polyols are obtained from natural oils, e.g., soybean
oil or palm oil, and can be used in unmodified or modified
form.
[0029] A suitable ratio of isocyanate to polyol, expressed as the
index of the formulation, is in the range from 10 to 1000,
preferably from 40 to 350. This index describes the ratio of
isocyanate actually used to calculated isocyanate (for a
stoichiometric reaction of polyol). An index of 100 refers to a
molar ratio of the reactive groups of 1:1.
[0030] Further suitable catalysts for the purposes of the present
invention are substances which catalyze the gelling reaction
(isocyanate-polyol), the blowing reaction (isocyanate-water) or the
dimerization or trimerization of the isocyanate. Typical examples
are amines such as triethylamine, dimethylcyclohexylamine,
tetramethylethylenediamine, tetra-methylhexanediamine,
pentamethyldiethylenetriamine, pentamethyldipropylenetriamine,
triethylenediamine, dimethylpiperazine, 1,2-dimethylimidazole,
N-ethylmorpholine,
tris(dimethylaminopropyl)hexahydro-1,3,5-triazine,
dimethylaminoethanol, dimethylaminoethoxyethanol and
bis(dimethylaminoethyl)ether, tin compounds such as dibutyltin
dilaurate and potassium salts such as potassium acetate. Preference
is given to using catalysts which do not contain any tin compounds,
in particular do not contain any tin organic compound, as
dibutyltin dilaurate, as further catalysts.
[0031] Suitable use amounts depend on the type of catalyst and are
typically in the range from of 0.01 to 5 pphp (=parts by weight per
100 parts by weight of polyol) or from 0.1 to 10 pphp for potassium
salts.
[0032] Suitable water contents for the purposes of the present
invention depend on whether or not physical blowing agents are used
in addition to water. In the case of purely water-blown foams, the
values are typically from 1 to 20 pphp; if other blowing agents are
used in addition, the amount used is usually reduced to 0 or 0.1-5
pphp. To achieve high foam densities, neither water nor other
blowing agents are used.
[0033] Suitable physical blowing agents for the purposes of the
present invention are gases, for example liquefied CO.sub.2, and
volatile liquids, for example hydrocarbons having 4 or 5 carbon
atoms, preferably cyclopentane, isopentane and n-pentane,
fluorinated hydrocarbons, preferably HFC 245fa, HFC 134a and HFC
365mfc, chlorofluorocarbons, preferably HCFC 141b,
oxygen-containing compounds such as methyl formate and
dimethoxymethane, or chlorinated hydrocarbons, preferably
dichloromethane and 1,2-dichlorethane. Further blowing agents that
can be used include ketones (e.g., acetone) or aldehydes (e.g.,
methylal).
[0034] Apart from water and, if appropriate, physical blowing
agents, other chemical blowing agents which react with isocyanates
to evolve gas, for example formic acid or carbonates, can also be
used.
[0035] Suitable flame retardants for the purposes of the present
invention are preferably liquid organic phosphorus compounds such
as halogen-free organic phosphates, e.g., triethyl phosphate (TEP),
halogenated phosphates, e.g., tris(1-chloro-2-propyl) phosphate
(TCPP) and tris(2-chloroethyl)phosphate (TCEP), and organic
phosphonates, e.g., dimethyl methanephosphonate (DMMP), dimethyl
propanephosphonate (DMPP), or solids such as ammonium polyphosphate
(APP) and red phosphorus. Furthermore, halogenated compounds, for
example halogenated polyols, and also solids such as expandable
graphite and melamine are suitable as flame retardants.
[0036] The processing of the formulations to produce foams can be
carried out by all methods with which those skilled in the art are
familiar, for example by manual mixing or preferably by means of
high-pressure foaming machines. It is possible to use batch
processes, for example for the production of moulded foams,
refrigerators and panels, or continuous processes, for example in
the case of insulation boards, metal composite elements, blocks or
sprayed foam.
[0037] The process of the invention makes it possible to obtain
polyurethane systems, in particular polyurethane foams, which are
characterized in that they comprise at least one or more carboxylic
acids to whose carbonyl carbon a hydrocarbon radical is bound, with
the proviso that the carboxylic acid does not have a single ethyl
or n-propyl group in the 2 position, or a metal salt thereof, in
particular the above-described carboxylic acids/salts. The
polyurethane systems of the invention, preferably polyurethane
foams, preferably comprise exclusively carboxylic acids or salts
thereof which are exclusively unbranched or have methyl group
branches.
[0038] Preferred polyurethane systems according to the invention,
in particular polyurethane foams, are characterized in that the
proportion by mass of carboxylic acids or carboxylates to whose
carbonyl carbon a hydrocarbon radical is bound, with the proviso
that the carboxylic acid does not have a single ethyl or n-propyl
branch in the 2 position, is from 0.001 to 5% by mass, based on the
weight of the overall foam, preferably from 0.01 to 1.5% by
mass.
[0039] The polyurethane systems of the invention can be, for
example, polyurethane coatings, polyurethane adhesives,
polyurethane sealants, polyurethane elastomers or polyurethane
foams, in particular a flexible polyurethane foam, a rigid
polyurethane foam, a viscoelastic foam, an HR foam, a semirigid
polyurethane foam, a thermoformable polyurethane foam or an
integral foam. The term polyurethane is here used as generic term
for a polymer produced from diisocyanates or polyisocyanates and
polyols or other species which are reactive toward isocyanate,
e.g., amines, with the urethane bond not having to be the exclusive
or predominant type of bond. Polyisocyanurates and polyureas are
expressly included.
[0040] The polyurethane systems of the invention, in particular the
polyurethane foams, can be used, for example, as refrigerator
insulation, insulation board, sandwich element, pipe insulation,
spray foam, 1- & 1.5-component can foam, imitation wood,
modelling foam, packaging foam, mattresses, furniture upholstery,
automobile seat upholstery, headrests, dashboards, automobile
interior trim, automobile roof cladding, sound absorption material,
steering wheel, shoe sole, carpet backing foam, filter foam,
sealing foam, sealant and adhesive.
[0041] The present invention is described by way of example in the
examples reported below without the invention, whose scope is
defined by the total description and the claims, being restricted
to the embodiments mentioned in the examples.
EXAMPLES
Examples 1 to 35
Production of Polyurethane Foams
[0042] The following formulation was used for producing
polyurethane foams: 100 parts by weight of polyetherol (hydroxyl
number=47 mg KOH/g, 11-12% of EO), 4 parts by weight of water, 1
part by weight of TEGOSTAB.RTM. BF 2370 (silicone stabilizer from
Evonik Goldschmidt GmbH), 0.1 part by weight of a tertiary amine,
50.6 parts by weight of toluene diisocyanate T 80 (Index 110) and a
variable amount of KOSMOS.RTM. 29 (tin octoate, Evonik Goldschmidt
GmbH) or the tin carboxylates to be examined. For comparison,
2-ethylhexanoic acid, 2-ethylbutyric acid and 2-propylheptanoic
acid, viz. molecules having a close structural relationship to tin
isononoate (tin salt of 3,5,5-trimethylhexanoic acid), were
selected as compounds not according to the invention.
[0043] Foaming was carried out using 400 g of polyol, and the other
constituents of the formulation were graduated accordingly. Table 1
summarizes the variable constituents of the formulations of example
foams 1 to 35.
[0044] To carry out foaming, the polyol, water, amine, tin catalyst
and silicone stabilizer were mixed well by stirring. After addition
of the isocyanate, the mixture was stirred for 7 seconds at 3000
rpm by means of a stirrer. The mixture obtained was poured into a
paper-lined wooden box (base area 27 cm.times.27 cm). This gave a
foam which was subjected to the use-related tests described
below.
TABLE-US-00001 TABLE 1 Variable constituents of the formulations of
example foams 1 to 35. Example According to Catalyst No. the
invention Salt.sup.[1] [parts by weight] 1 no a) 0.15 2 no a) 0.20
3 no a) 0.25 4 no a) 0.30 5 no a) 0.35 6 no b) 0.17 7 no b) 0.23 8
no b) 0.285 9 no b) 0.34 10 no b) 0.40 11 yes c) 0.16 12 yes c)
0.215 13 yes c) 0.27 14 yes c) 0.33 15 yes c) 0.38 16 yes d) 0.30
17 yes d) 0.40 18 yes d) 0.50 19 yes d) 0.60 20 yes d) 0.70 21 yes
e) 0.137 22 yes e) 0.18 23 yes e) 0.228 24 yes e) 0.274 25 yes e)
0.32 26 yes f) 0.128 27 yes f) 0.17 28 yes f) 0.213 29 yes f) 0.256
30 yes f) 0.299 31 yes g) 0.16 32 yes g) 0.21 33 yes g) 0.267 34
yes g) 0.32 35 yes g) 0.374 .sup.[1]a) = tin(II) salt of
2-ethylhexanoic acid b) = tin(Il) salt of 2-propylheptanoic acid c)
= tin(II) salt of isononanoic acid d) = tin(II) salt of n-octanoic
acid (50% diluted by weight in DPG) e) = tin(II) salt of
cyclohexanecarboxylic acid f) = tin(II) salt of
3,3-dimethylbutanoic acid g) = tin(II) salt of n-nonanoic acid
Physical Properties of the Foams
[0045] The foams produced were assessed by means of the following
physical properties:
a) Settling of the foams after the rise phase (=settling): [0046]
The settling, or after-rise, was given by the difference in the
foam height after direct release and 3 minutes after release of the
foam. The foam height was measured by means of a needle fastened to
a centimetre scale at the maximum in the middle of the foam dome.
b) Foam height: [0047] The final height of the foam was determined
by subtracting or adding the settling or the after-rise,
respectively, from or to the foam height after release. c) Foam
density (FD): [0048] The determination was carried out as described
in ASTM D 3574-08 under test A by measuring the core density. d)
Air permeability/porosity e) Compression load deflection CLD, 40%
f) Compression set after compression by 90% for 22 h at 70.degree.
C. g) Rebound resilience (ball rebound test)
[0049] Tests e) to g) were carried out in accordance with ASTM D
1564-71.
[0050] Test d) was carried out as follows:
Method:
[0051] The air permeability/porosity of the foam was determined by
means of a banking-up pressure measurement on the foam. The
measured banking-up pressure was reported in mm of alcohol, with
the lower banking-up pressure values characterizing the more open
foam. The values were measured in the range from 0 to 300 mm.
Apparatus:
[0052] The measurement apparatus was supplied by the in-house
nitrogen line and was therefore connected to the latter and
comprises the following parts connected to one another:
[0053] reducing valve with manometer,
[0054] flow regulating screw,
[0055] wash bottle,
[0056] flow measurement instrument,
[0057] T-piece,
[0058] lay-on nozzle,
[0059] graduated glass tube, filled with alcohol.
[0060] The wash bottle is only obligatory when the apparatus is not
supplied from the in-house line but directly with industrial
bottled gas.
[0061] The flow measurement instrument had to be calibrated in
accordance with the manufacturer's instructions using the
calibration curves supplied and provided with a marking at 8
l/min=480 l/h before being used for the first time.
[0062] The lay-on nozzle had an edge length of 100.times.100 mm, a
weight in the range from 800 to 1000 g, an internal width of the
outflow opening of 5 mm, internal width of the lower lay-on ring of
30 mm.
[0063] The measurement liquid (technical-grade alcohol (ethanol))
can be coloured to increase the optical contrast.
Measurement Procedure:
[0064] The nitrogen admission pressure was set to 1 bar by means of
the reducing valve. The flow was adjusted to the appropriate 480
l/h by means of the flow regulating screw. The amount of liquid in
the graduated glass tube was brought by means of alcohol to a level
at which no pressure difference is built up and can be read off.
For the actual measurement of the test specimen, five individual
measurements, four on the four corners and one in the middle of the
test specimen, were carried out. For this purpose, the lay-on
nozzle was laid on at the corners flush with the edges; the middle
of the test specimen is estimated. The reading was taken when a
constant banking-up pressure had been established.
Evaluation:
[0065] The upper measurement limit of the method was 300 mm of
liquid (CL). For recording, three different cases had to be
distinguished: [0066] 1. All five values were below 300 mm CL. In
this case, the arithmetic mean was formed and recorded. [0067] 2.
All five values were greater than or equal to 300 mm CL. In this
case, the value >300 or 300 should be recorded. [0068] 3. Of the
five measured values, a) values can be determined explicitly, b)
values were greater than or equal to 300: the arithmetic mean of
five values was formed, with 300 being used in each case for the b)
measured values. The number of values greater than or equal to 300
was also recorded separated from the mean by an oblique stroke.
Example: [0069] Four measured values correspond to 180, 210, 118
and 200 mm CL; one measured value was >300 mm CL
(180+210+118+200+300)/5. Recorded entry: 202/1.
[0070] The results are summarized in Table 2.
TABLE-US-00002 TABLE 2 Results of the determination of the physical
properties CLD Ex. Rise time Settling Height FD Porosity 40%
Compression Rebound No. [s] [cm] [cm] [kg/m.sup.3] [mm] [kPa] set
[cm] 1 112 -0.2 31.8 24.6 9 4.5 6 39 2 99 -0.2 33.4 23.9 33 5.2 9
42 3 92 +0.5 34.1 23.2 201 5.9 34 44 4 84 +1.2 35.3 25.8 300 7.1 72
42 5 80 +1.7 36.2 Shrinkage -- -- -- -- 6 119 +0.1 30.1 24.9 10 4.0
5 41 7 104 -0.2 30.9 25.0 17 4.5 8 41 8 95 -0.1 32.0 24.3 56 4.9 12
44 9 90 +0.4 32.7 23.0 300 5.3 74 41 10 86 +0.8 -- Shrinkage -- --
-- -- 11 131 +0.2 30.4 24.7 6 3.6 5 43 12 111 .+-.0.0 30.6 24.7 7
4.0 5 42 13 100 -0.1 31.2 24.7 10 4.4 6 41 14 90 .+-.0.0 32.1 24.3
43 4.9 9 40 15 85 +0.3 32.8 23.6 126 5.2 70 36 16 126 +1.1 30.3
24.1 8 3.5 5 46 17 107 -0.1 31.1 24.5 10 3.8 4 44 18 95 -0.1 31.6
24.6 13 4.2 4 42 19 87 -0.1 32.4 24.3 22 4.7 6 37 20 80 +0.1 32.7
24.0 104 5.0 7 40 21 120 +0.1 30.6 24.6 8 3.6 4 43 22 104 -0.1 31.1
24.6 10 4.0 5 42 23 92 -0.2 31.8 24.6 11 4.6 6 42 24 85 .+-.0.0
32.6 24.0 78 5.1 9 42 25 82 +0.6 33.5 22.8 300 5.6 81 46 26 111
.+-.0.0 30.8 24.7 8 3.9 4 43 27 95 -0.2 31.8 24.7 11 4.3 5 42 28 86
-0.2 32.7 24.2 44 4.8 7 32 29 79 +0.2 33.6 23.3 145 5.2 61 41 30 80
+0.6 -- Shrinkage -- -- -- -- 31 131 +0.2 31.0 26.1 8 2.9 6 43 32
115 +1.3 31.2 23.4 16 2.8 6 41 33 100 -0.1 31.4 24.3 16 3.2 6 41 34
88 -0.2 31.8 24.4 22 3.4 8 41 35 77 +0.1 32.4 23.9 87 3.8 25 37
[0071] As can be seen from the low settling values, stable
polyurethane foams can be produced with addition of the metal salts
according to the invention of (methyl)alkylcarboxylic acids. The
proportions by weight of the respective catalysts were calculated
so that the tin content in the systems to be compared is equimolar.
When the amount of, for example, tin isononanate is increased, the
open-cell nature of the foams is only reduced from 6 to 126 mm of
ethanol banking-up pressure, in the case of n-octanoic acid only
from 8 to 104 mm. In comparison, significantly smaller amounts of
tin octoates (tin 2-ethylhexanoate or tin propylheptanoate) lead to
very closed-celled foams through to high shrinkage (Examples 3 to 5
and 8 to 10; mm>300).
Determination of the Emissions
[0072] The acid emission was determined by a method based on the
Mercedes-Benz test method PB VWT 709.
[0073] The procedure for thermodesorption with subsequent coupled
gas chromatography-mass spectrometry (GC/MS) is described
below.
a) Measurement technique: [0074] The thermodesorption was carried
out using a thermodesorber "TDS2" with sample changer from Gerstel,
Mulheim, in combination with a Hewlett Packard HP6890/HP5973
GC/MSD-system. b) Measurement conditions:
TABLE-US-00003 [0074] Thermodesorption Gerstel TDS 2 Desorption
temperature 90.degree. C. Desorption time 30 min Flow 60 ml/min
Transfer line 280.degree. C. Cryofocussing HP 6890 PTV Liner glass
vaporizer tube with silanized glass wool Temperature -150.degree.
C. GC Capillary GC HP 6890 Injector PTV split 1:50 Temperature
programme -150.degree. C.; 3 min; 720.degree. C./min; 280.degree.
C. Column 60 m * 0.25 mm Optima 5 MS dF 0.5 .mu.m Flow 1 ml/min
const. flow Temperature programme 50.degree. C.; 5 min; 3.degree.
C./min; 92.degree. C.; 5.degree. C./min; 160.degree. C.; 10.degree.
C./min; 280.degree. C.; 20 min Detector HP MSD 5973 Mode Scan
29-350 amu 2.3 scans/sec Valuation valuation of the total ion
current chromatogram Calculation of the 2-ethylhexanoic acid peak
as toluene equivalent
c) Calibration
[0075] For the calibration, 1 .mu.l of a mixture of toluene and
hexadecane in pentane (each 0.6 mg/ml) was introduced into a
cleaned adsorption tube filled with Tenax TA (mesh 35/60) and
measured (desorption: 5 min; 280.degree. C.) d) Sample preparation
[0076] 10 mg of foam in three part specimens were pushed into a
thermodesorption tube. Care was taken to ensure that the foam was
not compressed.
e) Evaluation
[0076] [0077] To quantify the acid emission, the peak identified
as, for example, 2-ethylhexanoic acid by means of the mass spectrum
was determined as ppm of toluene equivalent via its peak area using
the response factor of toluene from the calibration.
[0078] Table 3 summarizes the results of the acid emissions of
selected examples.
TABLE-US-00004 TABLE 3 Results of the emission determinations
Pro-portion according to Total Acid of total the Tin catalyst
emission emission emission No. invention Acid [parts] [.mu.g/g]
[.mu.g/g] [.mu.g/g] 2 no 2-Ethyl- 0.2 830 613 74 hexanoic 12 yes
Isononanoic 0.215 770 512 66 7 no 2-Propyl- 0.23 1190 805 68
heptanoic 17.sup.[2] yes n-Octanoic 0.2 500 202 40 32 yes
n-Nonanoic 0.215 380 119 31 .sup.[2]without dilution in DPG
[0079] It can clearly be seen from the results that the emission
was significantly reduced by use of acids which do not have a
2-ethyl or 2-propyl branch, e.g., isononanoic acid, n-octanoic acid
or n-nonanoic acid.
Example 36
Determination of the Influence of the Catalyst Content (Tin
Content) on the Porosity of the Foams
[0080] Foams were produced as indicated in Examples 1 to 35, with
the concentration of catalyst system being varied. The foams were
produced using tin salts of 2-ethylhexanoic acid,
3,3-dimethyl-butyric acid, 2-propylheptanoic acid,
cyclohexanecarboxylic acid and n-octanoic acid. The foams obtained
were examined to determine their porosity. The results of these
tests are shown in the sole FIGURE that accompanies the present
application.
[0081] It can easily be seen that when catalyst systems based on
cyclohexanecarboxylate, but in particular when based on n-octanoate
and isononanoate, were used, a reduction of the air permeability
was observed only at significantly higher concentrations. The
corresponding catalyst systems thus allowed a considerably greater
processing latitude. Particularly when ethyl- and n-propyl-branched
carboxylic acids were used, a catalyst system varied slightly in
the direction of higher use amounts leads to very closed foams or
high shrinkage.
[0082] While the present invention has been particularly shown and
described with respect to preferred embodiments thereof, it will be
understood by those skilled in the art that the foregoing and other
changes in forms and details may be made without departing from the
spirit and scope of the present invention. It is therefore intended
that the present invention not be limited to the exact forms and
details described and illustrated, but fall within the scope of the
appended claims.
* * * * *