Note: Descriptions are shown in the official language in which they were submitted.
213~32,~
Mo4095
LeA 29,886
PROCESS FOR THE PRODUCTION OF FLEXIBLE
FOAMS CONTAINING URETHANE GROUPS
-
BACKGROUND OF THE iNVENTlON
Polyurethanes, like all other plastics, are suitable for material
recycling. There are several approaches to the reuse of polyurethanes,
some involving physical reprocessing, and some chemical reprocessing.
\larious reactions for the chemical degradation of polyurethane are listed
in the review article entitled "Chemical Degradation of Polyurethane" by - -
Vincent Gajewski, published in Rubber World, September 1990, pages
15 to 18. These reactions include hydrolysis, thermolysis, oxidation,
photolysis, pyrolysis, solvolysis, and microbial degradation.
If the processes are evaluated with particular regard to the :
processability of the breakdown products, there are several reactions
which are particularly significant for recycling purposes. These include
hydrolysis and alcoholysis.
Hydrolysis (E. Grigat, Kunststoffe, 68, (1978), p. 12) yields
polyol/amine mixtures with CO2 as a by-product. The degradation
products may be very readily reused.
Alcoholysis (G. Bauer in K.J. Thome-Kozminsky (editor~ Recvclinq
International, vol. 1, EF-Press, Berlin 1989, p. 415 and F. Simioni, S.
Bisello, Cell.PolYm. 2 (1983), p. 281) effects a reaction using short-chain
diols which yields polyhydroxy alcohols and low molecular weight
urethane structures.
Since it is possible in both cases (hydrolysis and alcoholysis) to
develop formulatians which, by adding fresh polyol and fresh isocyanate,
yield polyurethane foam or similar products, processes such as pyrolysis
to produce cracker products are of less interest and are comparatively
distant from the product.
/vj t/AN4095
... . ~,. . ,; ~ . .; , -. -
:-' 2130~
-2 -
Another recycling option involves adding finely powdered
polyurethane foam (produced, for exampie, in accordance with German
Patent 4,200,443) to the polyol component during polyurethane
production (as described, for example, in U.S. Patent 4,692,470).
The basic requirements which must be fulfilled to achieve
processability in this case are a particular grain size of the ground
polyurethane material and its even distribution in the polyol, while
simultaneously ensuring the highest possible content of ground material
and low viscosity.
The common feature of hydrolysis, alcoholysis and the
incorporation of ground foam into the polyol component is that they
require a formulation specially tailored to their products as polyurethane
raw materials.
Moreover, for technical reasons (viscosity, stability of the
suspension, tendency of foam to collapse), the quantity of powdered
foam which may be added is limited.
It has now surprising been found that the quantity of polyurethane
which may be reprocessed may be iricreased by chemically incorporating
comminuted foam or non-cellular polyurethane in the form of chopped
material, powder or flakes into the isocyanate component under particular
conditions. The resultant isocyanate prepolymers may be used directly as
a polyurethane raw material in foam, or for the production of non-cellular
polyurethanes.
Equally surprising and also largely unpredictable for the person
skilled in the art is the fact that the open-cell nature of the resultant foam
which may be observed when powdered foam is added to the polyol
component is avoided when the prepolymers according to the invention
are added, so that all that is required is slight optimization of the
formulation.
Mo4095
, .~ ,.-. .
~ .: . -, - .
:' 21~32~
-3 -
DESCRIPTION OF THE INVENTION
The present invention provides a process for the production of
flexible foams containing urethane groups by the reaction of a reaction
mixture comprising;
1) modified polyisocyanates,
2) organic compounds having molecular weights of 400 to
10,000 and containing at least two isocyanate-reactive
hydrogen atoms, ~;
and
3) and a blowing agent selected from the group consistin~ of ~ -
water, organic blowing agents, and mixtures thereof,
wherein the modified polyisocyanates are prepared by reacting
polyurethanes with polyisocyanates, in the presence of acylating agents,
alkylating agents, or mixtures thereof.
The reac~ion mixture may additionally comprise:
4) compounds having molecular vveights of 32 to 399 and
containing at least two isocyanate-rsactive hydrogen atoms
as crosslinking agents,
and, optionally,
5) perse known auxiliary substances and/or additives,
In a preferred embodiment of the invention, the polyurethanes are
present in an amount of from 1 to 50% by weight, preferably from 5 to
45% by weight, based on the total weight of the modified
polyisocyanates. It is also preferred that the polyurethanes are present in
the forrn of powders, flakes, chopped material, or mixtures thereof.
The quantity of acylating agent used is generally from 0.71 to 3.6
mmol, preferably 0.71 to 2.6 mmol, per 1,000 9 of the modified
isocyanate. If alkylating agents are used, the quantity is generally from
Mo4095
-```` 21~32 ~
-4 -
0~02 to 1.1 mmol, preferably 0.054 to 0.54 mmol, per 1,000 9 of the
modified isocyanate.
The present invention also relates to flexible polyurethane foams
produced according to the above-stated process.
The following components are suitable for producing the flexible
foams containing urethane groups.
Suitable modified polyisocyanates include, for example, those ~
.:
produced from the reaction of a) starting polyisocyanates of the following
formula~
1 0
Q(NCO)nl
wherein: ~
~
n represents 2 to 4, preferably 2 to 3, ~ :
and
Q represents an aliphatic hydrocarbon residue with 2 to 18, ~:
preferably 6 to 10 carbon atoms, a cycloaliphatic . ~.
hydrocarbon residue with 4 to 15, preferably 5 to 10
carbon atoms, an aromatic hydrocarbon residue with 6 to
15 carbon atoms, or an araliphatic hydrocarbon residue with
8 to 15, preferably 8 to 13 carbon atoms,
with b) polyurethanes, in the presence of c) acylating and/or alkylating
agents.
Particularly preferred starting polyisocyanates include, for example,
hexamethylene diisocyanate, 1,12-dodecane diisocyanate, 1,3-cyclo- ~-
butane diisocyanate, 1,3- and 1,4-cyclohexane diisocyanate together with
any desired mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-
- isocyanatomethylcyclohexane, hexahydro-1,3- and/or -1 ,4-phenylene
diisocyanate, perhydro-2,4'- and/or -4,4'-diphenylmethane diisocyanate,
Mo4095
. ,:, - - , ~ , . . .
~ 2~3032~
`
-5-
1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate
together with any desired mixtures of these isomers, 2,4'- and/or 4,4'-
diphenyl-methane diisocyanate, 1,5-naphthylene diisocyanate,
4,4',4"-triphenylmethane triisocyanate, or polyphenyl/ polymethylene ;~
polyisocyanates, as are obtained by anilinelformaldehyde condensation
and subsequent phosgenation.
Suitable higher molecular weight s~arting polyisocyanates include
the modification products of such simple polyisocyanates, i.e. poly-
isocyanates with, for example, isocyanurate, carbodiimide, allophanate,
biuret or uretidione structural units, as may be produced using per se
known processes from the exemplified simple polyiso-cyanates of the
above-stated general formula. Of the higher molecular weight, modified
poiyisocyanates, those prepolymers known from polyurethane chemistry
with terminal isocyanate groups merit particular mention.
16 These prepolymers are produced in a per se known manner by the
reaction of excess quantities of simple polyisocyanates of the exemplified
type with organic compounds having at least two groups which are
reactive with isocyanate groups such as, for example, organic
polyhydroxyl compounds.
In the context of the present invention, "NC0 prepolymers" or
"prepolymers with terminal isocyanate groups" should be taken to mean
both the reaction products themselves and their mixtures with excess
quantities of unreacted starting polyisocyanates, which are often also
described as "semi-prepolymers".
Starting polyisocyanates which are particularly preferred according
to the invention include the technical polyisocyanates customary in
polyurethane chemistry, i.e. hexamethylene diisocyanate, 1-isocyanato-
3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate,
abbreviated as IPDI), 4,4'-diisocyanatodicyclohexylrnethane, 2,4-diiso-
Mo4095
--~ 2l3n~2C~
-6 -
cyanatotoluene and its technical mixtures with 2,6-diisocyanatotoluene,
4,4'-diisocyanatodiphenylmethane and its mixtures with the corresponding
2,4'- and 2,2'-isomers, polyisocyanate mixtures of the diphenyimethane
series, as may be obtained in a known manner by phosgenation of
5 aniline/formaldehyde condensation products, the modification products of
these technical polyisocyanates containing biuret or isocyanurate groups
and, in particular, NCO prepolymers of the stated type based on these
technical polyisocyanates, and the exemplified simple poiyols and/or
polyether polyols and/or polyester polyols, together with any desired
10 mixtures of such polyisocyanates.
Suitable polyurethanes include, for example, any cellular and non~
cellular polyurethanes, such as, for example, slab, molded, hot or cold
foams, thermoplastic polyurethanes, RIM polyurethane, elastomers, etc.
What is primarily of interest for processing, is the fact that the poiy-
15 urethane need not be finely powdered, but may instead be very coarselygrained, even in the form of flakes, chopped material, and mixtures
thereof. As a result, the costly grinding operations and the separation of
particle sizes by screening or air classifying may be dispensed with. The
proportion of polyurethane may be 1 to 50%, preferably 5 to 45% by
20 weight, based on the total weight of the modified polyisocyanate`
component. -
Acylating or alkylating substances are also used in the production
of the modified polyisocyanates according to the invention. These
substances are per se known, and often used as stabilizers in
25 polyurethane chemistry. Acylating agents include, for example, acid
chlorides, such as, for example, benzoyl chloride, isophthaloyl chloride
etc. In general, suitable compounds correspond to the general formula:
(COCl)n
Mo4095
.,.. .. ~ .. .. .. . . . . . ..
~` 213~322
;.
-7- -
wherein: n = 1 or 2.
Some examples of suitable alkylating agents include, for example,
methyl iodide, dimethyl sulfate, or, preferably sulfonic acid alkyl esters
having molecular weights of from 110 to 250 and containing from 1 to 4
5 carbon atoms in the alkyl residue. These include, for example, both
aliphatic sulfonic acid alkyl esters such as methyl methane-sulfonate,
methyl n-butanesulfonate, methyi n-per~uoro-butanesulfonate, ethyl n-
hexanesulfonate; and aromatic sulfonic acid alkyl esters such as, for
example, methyl-, ethyl- or n-butyl-benzenesulfonate, methyl-, ethyl- or
10 n-butyl-p-toluenesulfonate, methyl 1-naphthalenesulfonate, methyl
3-nitrobenzenesulfonate or methyl 2-naphthalenesulfonate. The aromatic
sulfonic acid alkyl esters are preferred. Methyl p-toluenesulfonate is
particularly preferred.
The quantity of acylating agent to be used in preparing the
15 modified polyisocyanates is generally from 0.71 to 3.6 mmol, preferably
0.71 to 2.6 mmol, per 1,000 g of the modified polyisocyanate. If alkylating
agents are used, the quantity is generally from 0.02 to 1.1 mmol,
preferably 0.054 to 0.54 mmol, per 1,000 g of the modified isocyanate.
Suitable isocyanate-reactive compounds for the present invention
20 include organic compounds having molecular weights of from 400 to
10,000, and containing at least two isocyanate-reactive hydrogen atoms,
and having from 2 to 8, preferably 2 to 6, hydroxyl functional groups.
These molecular weights should be calculated from the OH value of the
substance according to the following equation:
M I I ~ 5B000
Mo4095
~" 213~32.3
. . .
-8-
Suitable compounds include, for example, polyhydroxy polyethers
of the type known per se in polyurethane chemistry. These polyhydroxy
polyethers may be obtained, for example, by the alkoxylation of suitable
initiator molecules such as ethylene glycol, diethylene glycol,
5 1,4-dihydroxybutane, 1,6-dihydroxyhexane, trimethylol-propane, glycerol,
pentaerythritol, sorbitol or saccharose. The following compounds may
also act as initiators: ammonia, or amines such as, for examplel
ethylenediamine, hexamethylenediamine, 2,4-diaminotoluene, aniline, or
amino alcohols. Alkoxylation proceeds using propylene oxide and/or
10 ethylene oxide in any desired order.
Polyester polyols are also suitable for the process of the present
invention. These may be obtained in a per se known manner from the
reaction of the exemplified low molecular weight alcohols with polybasic
carboxylic acids such as, for example, adipic acid, phthalic acid,
15 hexahydrophthalic acid, tetrahydrophthalic acid, and the anhydrides of
these acids.
Also, suitable compounds include, for example, those higher
molecular weight polyhydroxy polyethers wherein high molecular weight
polyaddition or polycondensation products or polymers are present in a
20 finely dispersed, dissolved or grafted form. Such modified polyhydroxyl
compounds include, for example, those obtained when polyaddition
reactions ~for example, reactions between polyisocyanates and amino-
functional compounds) or polycondensation reactions (for example,
between formaldehyde and phenols andlor amines) are allowed to
25 proceed in situ in the compounds containing hydroxyl groups. Such
processes are, for example, described in German Patents 1,168,075,
1,260,142, 2,324,134, 2,423,984, 2,512,385, 2,513,815, 2,550,796,
2,550,797, 2,550,833, 2,550,862, 2,633,293 and 2,639,254. However, it
is also possible, as described in U.S. Patent 3,869,413 or German Patent
Mo4095
.
,.. ,,: : ., .. . " .
2~32~
g
2,550,860 to mix a finished polymer dispersion with a polyhydroxyl
compound and to subsequently eliminate the water from the mixture.
Polyhydroxyl compounds modified with vinyl polymers, including
those obtained, for example, by polymerization of styrene and
5 acrylonitrile in the presence of polyethers (as described in, f~r example,
U.S. Patents 3,383,351, 3,304,273, 3,523,093, and 3,110,695; and
German Patent 1,152,S36) or polycarbonate polyols (as described in, for
example, German Patent 1,769,795; US-A-3,637,909), are also suitable
as component 2) in the process according to the invention. If polyether
polyols are used, which have been modified in accordance with, for `
example, German Patents 2,442,101, 2,644,922 and 2,646,141, by graft
polymerization with vinylphosphonic acid esters and, optionally, ~rneth)
acrylonitrile, (meth)acrylamide or OH-functional (meth)acrylic acid esters,
then flame resistant foams are obtained.
Representatives of the stated compounds which are suitable for
use as component 2) according to the invention include, for example,
those described in High Polymers, vol. XVI, Polyurethanes, Chemistry
and Technology, edited by Saunders-Frisch, Interscience Publishers,
New York, London, volume 1, 1962, pages 32 to 42 and pages 44 to 54
20 and volume ll, 1964, pages 5 to 6 and 198 to 199, and in Kunststoff-
Handbuch, volume Vll, Vieweg-Hochtlen, Carl Hanser Verlag, Munich,
1966, for example of pages 45 to 71.
Also suitable compounds to be used as component 2), or as parl
of component 2), are polyether polyamines with terminal aliphatic and
25 aromatic primary amino groups. These compounds are obtainable using
the processes described in, for example, European Patent Application ~-
79,536, German Patents 2,948,419,2,019,432, and 2,619,840; and U.S. ~ ~ :
Patents 3,808,250,3,975,426 and 4,016,143. Polyether polyols having ~ i
Mo4095
213~322
-10-
molecular weights of from 2,000 to 6,000, and a functionality of 2 to 6 are
preferred.
Suitable compounds to be used as blowing agents according to
the present invention include water, organic blowing agents, and mixtures
5 thereof. Generaliy speaking, the amount of water used as the blowing
agent is from 0.5 to 10 parts by weight, per 100 parts by weight of
organic compounds having molecular weights of 400 to 10,000 and
containing at least two isocyanate-reactive hydrogen atoms.
Organic compounds may also be used as blowing agents either
10 alone, or in conjunction with water. Suitable organic compounds include,
for example, liquids which are inert to the modifled polyisocyanates, and
have boiling points of below 100C, preferably below 50C, and most
preferably between -50C and 30C at atmospheric pressure, such that
they vaporize under the action of the exothermic polyaddition reaction.
15 Examples of these most preferred liquids inciude hydrocarbons such as,
for example, pentane, cyclopentane, n- and iso-butane and propane,
ethers such as, for example, dimethyl ether and diethyi ether, ketones
such as, for example, acetone and methyl ethyl ketone, ethyl acetate and
halogenated hydrocarbons such as, for example, methylene chloride,
20 trifluoromethane, dichloro-difluoroethane and 1,1,2-trichloro-1,2,2-
trifluoroethane. Mixtures of these low-boiling liquids with each other
and/or with other hydrocarbons containing other substituents, or with
unsubstituted hydrocarbons may also be used. Additional details relating ~ ;
to the content of the above-stated organic blowing agents in formulations
25 and the properties of the resultant flexible polyurethane foams may be
found in Kunststoff-Handbuch, volume Vll, Vieweg-Hochtlen, Carl Hanser
Verlag, Munich 1983, for example on pages 194 et seq. ~:
Suitable compounds to be used as chain-extending agents and/or
cross-linking agents according to the present invention include those
Mo4095
~ ~13~32 i
-11-
compounds having molecular weights of 32 to 399 and containing at
least two isocyanate-reactive hydrogen atoms. These compounds
containing at least two isocyanate-reactive hydrogen atoms which are
present in the form of, for example, hydroxyl groups, amino groups, thiol
5 groups, carboxyl groups, or mixtures thereof. It is preferred that these
compounds containing hydroxyl groups. These compounds generally
have from 2 to 8, and preferably 2 to 4 isocyanate-reactiYe hydrogen
atoms. Some examples of such compounds are described in, for
example, German Patent 2,832,253 at pages 19 to 20.
The reaction mixtures of the invention may also include the
auxiliary substances and additives which are known per se in poly-
urethane chemistry. These include, for example, surface-active additives
such as, for example, emulsifiers and foam stabilizers; and fillers, dyes
and pigments. Additional details concerning customary auxiliary
substances and additives may be found in the literature such as, for
example, the monograph by J.H. Saunders and K.C. Frisch Hiah
Polvmers, volume XVI, Polyurethanes, parts 2 and 7, IntersGience
Publishers 1962 and 1964 respectively.
It is also possible to use catalysts in the reaction mixtures of the
present invention. Although any of the known catalysts may be used, it is
preferred that organic Sn(il) and/or Sn(lV) compounds, and, in particular,
Sn(ll) and Sn(lV) derivatives of higher carboxylic acids ,and/or preferably ~ :
tertiary amine catalysts be used. Suitable tertiary amine catalysts include
compounds such as, for example, dimethylbenzylamine, dicyclo-
hexylamine, dimethyl-cyclohexylamine, N, N, N', N'-tetramethyldiamino- -
diethyl ether, bis~dimethylaminopropyl)urea, N-methyl- or N-ethyl- ~ ~ -morpholine, dimethylpiperazine, N-dimethyl-aminoethylpiperidine, 1,2
dimethylimidazole, dimethyl-aminoethanol, and, in particular,
triethylenediamine and N,N'-bis(3-dimethylaminopropyl)formamide.
Mo4095
r~, 2 ~ 2 ~i
-12-
Performance of the process according to the invention:
According to the invention, the reaction components are reacted
using the per se known single stage process, prepolymer process or
semiprepolymer process, wherein machinery such as, for example, that
described in U.S. Patent 2,764,565 is often used. This reaction may
proceed in open or closed molds. Details of processing equipment which
may also be considered according to the invention are given in
_nststoff-Handbuch, volume Vll, edited by Vieweg and Hochtlen, Carl
Hanser Verlag, Munich 1966, ~or example on pages 121 to 205.
The reaction is generally performed at an isocyanate index of from
90 to 300, preferably 100 to 250. If higher indices are used, isocyanurate
structures are also produced in the foam.
As used herein, the term "Isocyanate Index" ~also commonly
referred to as NC0 index), is defined herein as the equivalents of
isocyanate, divided by the total equivalents of isocyanate-reactive
hydrogen containing materials, multiplied by 100.
If, during foam production, foaming is performed in closed molds,
the reaction mixture is introduced into a mold. Mold materials which may
be considered are metal, for example aluminum, or plastics, for example --
epoxy resin. The foamable reaction mixture foams in the mold and forms
the molded part. Mold foaming may be performed such that the surface
of the molded part has a cellular structure. It may, however, also be
performed such that the molded part has a compact skin and a cellular
core. According to the invention, it is possible in this connection to
introduce a quantity of reaction mixture in the mold such that the
resultant foam exactly fills the mold. It is, however, also possible to
introduce more foamable reaction mixture into the mold than is necessary
to fill the mold cavity with foam. This latter case is known as
Mo4095
. ;..~ -,~ -, ... .:
:.. .; -. :
.,, .. . , ~ . ,
2~3~ .~2SJ
-13-
"overcharging": such a method is known and, for example, described in
U.S. Patents 3,178,490 and 3,182,104.
In mold foaming, it is common to use the per se known "external
release agents" such as, for example, silicone oils. It is, however, also
5 possible to use the so-called "internal release agents", optionally in
combination with external release agents such as, for example, described
in German Patents 2,121,670 and 2,307,589.
Foams may, of course, also be produced by slab foaming or using
the per se known twin belt process.
The flexible polyurethane foams obtained according to the
invention are preferably used in applications such as, for example,
seating upholstery and head rests, or as backing foam for acoustic
foams.
The invention is further illustrated but is not intended to be limited
by the following examples in which all parts and percentages are by
weight unless otherwise specified.
EXAMPLES
A. Starting materials (all quantities are stated in wt.%)
Polvether 1:
A polyether initiated with trimethyolpropane and prepared by
propoxylation, which is terminally extended with approximately
18% EO; having an OH value of 28.
PolYether2: ~ -
A polyether initiated with propylene giycol and prepared by
propoxylation, which has a mixed block consisting of 39% ethylene
oxide and 46% propylene oxide on the propoxyiation product and -
is terminally extended with 9.5% ethylene oxide; having an OH -~
value 56.
Mo4095
s ~ ~
.. .! - ~: : . - ~ : : :: :
213~
-14-
PolYether 3:
A polyether initiated with trimethylolpropane and prepared by
propoxylation, which is terminally extended with 14% ethylene
oxide; having an Ol I value of 28.
5 Polyether 4:
A polyether initiated with trimethylolpropane and prepared by
propoxylation, which is terminally extended with 18% EO; having
an OH value of 35. This polyether additionally oontains 20% of a
reaction product of styrene and acrylonitriie as an organic filler,
resulting in an OH value of 28 for the overall mixture.
Catalyst 1:
Bis-N,N'-dimethylaminodiethyl ether (70% in dipropylene glycol).
Catalyst 2~
Triethylenediamine (33% in dipropylene glycol).
15 Catalvst 3:
N,N'-bis(3-dirnethylaminopropyl)formamide.
Stabilizer 1: '~
Tegostab~ B 4617, commercial product available from Th.
-
Goldschmidt AG.......................................... ~ -
20 Stabili~er2-
Tegostab~ B 8002, commercial product available from Th.
Goldschmidt AG. ~ '
Stabilizer 3:
Tegostab~ B 4113, commercial product available from Th.
GoldschmidtAG.
Cell or~ener: -
A polyether initiated with sorbitol and prepared by propoxylation,
which is terrninally extended with 82% ethylene oxide; having an
OH value of 100.
Mo4095
.,.' ' .. ' ` .~' . . . '
2 1 3 ~
-15-
lsocvanate 1:
An isocyanate mixture prepared by the phosgenation of an
aniline/formaldehyde condensation product with a dicyclic fraction
of B5%, 20% of which is 2,4'-diisocyanatodiphenylmethane, and
the remaining 80% consists of the 4,4'-isomer.
Isocvanate 2 ~accordin~ to the inve~
An isocyanate as described in isocyanate 1, containing 20% of a
polyurethane foam in dissolved form.
Preparation of isocyanate 2: 800 g of isocyanate 1 and 200 g of a
flexible polyurethane foam powder are introduced into a vessel with 6.5 9
of a 1 m solution of methyl p-toluenesulfonate in isocyanate 1 and heated
to 150C while being stirred. Once the reac~ion mixture has become
highly fluid, it is stirred for a further 1 hour at 1 50C. The isocyanate ~-
content is 22.5%.
IsocYanate 3~
An isocyanate mixture prepared from a) an 80:20 mixture of the
2,4- and 2,6- isomers of tolylene diisocyanate and b) poiymeric
4,4'-diiso-cyanatodiphenylurethane in an a:b ratio of 80:20 (NCO
content: 44.5%).
Isocvanate 4 (accordinq to the invention~
A mixture of 20 parts of polymeric 4,4'-diisocyanatodiphenyl- ~ :
methane and 100 parts of a solution of 20% flexible polyurethane
foam powder in a mixture of the 2,4- (80%) and 2,6- (20%)
isomers of tolylene diisocyanate. The diisocyanate content is
35.3%. ~ ~
Preparation of the solution: 800 9 of the tolylene diisocyanate ~ - -
isomer mixture (described under isocyanate 4), 200 9 of polyurethane
and 6.5 g of a 1 molar-solution of methyl p-toluene-sulfonate in the u
tolylene diisocyanate isomer mixture (described under isocyanate 4) are
Mo4095
' ~
., ., , - . ,.., , ., .; " - . -
.. . ... .. .. . . .
~3~
-16-
introduced together into a vessel and heated to 150C while being
stirred. Once the viscosity of the reaction mixture has markedly reduced,
the mixture is stirred for a further 1 hour at 150C. The isocyanate
content is 36%.
5 Isocvanate 5:
A mixture of 30 parts of polymeric 4,4'-diisocyanatodiphenyl-
methane and 70 parts of a mixture of the 2,4- (65%) and 2,6- (35%)
isomers of tolylene diisocyanate. The isocyanate content is 43.2%.
Isocyanate 6 (accordina to the invention~:
A mixture of 30 parts of polymeric 4,4'-diisocyanatodiphenyl-
methane and 87.5 parts of a solution of 20% flexible polyurethane foam
powder in a mixture of the 2,4- (65%) and 2,6- (35%~ isomers of tolylene
diisocyanate.
Preparation of the solution: The solution is prepared according to
16 the process described in isocyanate 4. All parameters remain the same,
except that the tolylene diisocyanate isomer mixture described herein-
above under isocyanate 6 is substituted for the tolylene diisocyanate
isomer mixture of isocyanate 4. The isocyanate content is 35%.
B. Foam production:
A!l the constituents of the formulation apart from the isocyanate
are weighed out into a paperboard beaker and mixed until homogeneous
with a high speed stirrer. After addition of the isocyanate, the mixture is
again vigorously stirred and thereupon poured into a wooden box mold
lined with paper.
The following summary tables reproduce the foam formulations for
examples 1 to 6, including an evaluation of the foams produced. The
expression recycling proportion denotes the proportion of reused
polyurethane in the resulting foam.
Mo4095
~ . ,; . .. ~ - ~ .. , , . -
~ ~fl32~,~
-17-
The recycling proportion is calculated from the sum of the
polyurethane powder and the polyurethane-content of the isocyanate.
See, for example, example 1: from the quantity of the polyurethane
powder (25 parts by wt.), and the polyurethane-content of the isocyanate
(75 parts by wt., NCO content = 20%, which results in 15 parts by wt.).
25 parts by wt. + 15 parts by wt. = 40 parts by wt. total reused
polyurethane. Since there are 209.75 total parts in the foam formulation
and 40 pbw of reused polyurethane, then 19.1% of the prepared foam
consists of reused polyurethane.
.
,", ~ ~
. .
Mo4095
3~
- -18-
Table 1: Foams based on 4,4'-diisocyanatodiph~nylmethane
Constituents Example 1 Example 2
According to the invention Comparison
(parts by weight) (parts by weight)
Polyether 1 90 90
Polyether 2 10 10
H2O 3.5 3.5 ~:
Catalyst 1 0.2 02
15 Catalyst 2 0.35 0-35
Stabilizer 1 1.0 1.0
Diethanolamine 0.5 0.5
Cell opener 4.0 4.0 -
2-ethylhexanoic acid 0.2 Q.2
25 Polyurethane powder 25 45.4
Isocyanate 1 - 55.1
Isocyanate 2 75
Recycling proportion 19.1% 21.6%
Bulkdensity (kg/m3) 72.5 Collapse offoam
35 Compressive strength (kPa) 2.3
Mo4095
2~3~32~
-19-
Table ~ Foams based on 4,4'-diisocyanatodiphenylmethane/ tolylene
diisocyanate mixtures :
Constituents Example 3 Exampie 4
Comparison According to the invention
(parts by weight) (parts by weight) -:
Polyether3 60 60 -
10 Potyether 4 40 40 ~ - :
H2O 3.8 3.8
Catalyst 1 0.05 0.05
- --
Catalyst2 0.25 0.25
Catatyst 3 0.45 0.45 ; ~:
20 Diethanolamine 1.0 1.0
Stabilizer 1 2.0 2.0 :-
Stabilizer2 0.1 û.1 ~ ~
:-
Cell opener 1.S 1.5 ~ -
Isocyanate 3 48.1 - ~ ~ -
30 tsocyanate 4 - 60.6
Polyurethane powder 25 25
Recycling proportion 13.7% 18.0%
Bulk density (kg/m3) Collapse offoam 57.5
Open-cell nature open-celled
40 Pore structure regularArregular
(typical cold foam pores)
Mo4095
`-`-` 2~3~32~
-20-
Table 3: Foams based on 4,4'-diisocyanatodiphenylmethane/ tolylen~ :
diisocyanate mixtures
Constituents Example 5 Example 6
Comparison According to the invention ~:-
(parts by weight) (parts by weight)
Polyether 3 60 60
Polyether 4 40 40
H2O 3.8 3.8 :
Catalyst 1 0.05 0.05
Catalyst 2 0.25 0.25
Catalyst 3 0.45 0 45
Diethanolamine 0.4 0.6
Stabilizer 1 - 0.6
Stabilizer 3 1.0
Isocyanate 5 45.&~
Isocyanate 6 - 57.0
Recycling proportion 0% 6.0%
Bulk density (kg/m3) 40.5 42.5
Compr~ssive strength (kPa) 6.2 6.1
Compression set (50%) (%) 5.6 8.6
Elongation at break ~%) 105 96
Tensile strength (kPa) 157 142
Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood that such
45 detail is solely for that purpose and that variations can be made therein
by those skiiled in the art without departing from the spirit and scope of
the invention except as it may be limited by the claims.
Mo4095
