Note: Descriptions are shown in the official language in which they were submitted.
Mo-1429-H
` 1053~Z4 LeA 15,511
PROCESS FOR MOLDING POLYURETHANE FOAMS
This invention relates generally to the molding of
foam plastics and more particularly to an improved mold release
agent for foamable reaction mixtures which form polyurethane
foams.
Polyurethane foams having a dense outer skin and a
cellular core of the kind which can be obtained by foaming in
a mold (German Auslegeschrift No. 1,196,864 and French Patent
Specification No. 1,559,325) are particularly suitable for the
series production of lightweight buil~ding constructions, for
example of the kind used in the manufacture of furniture,
cushioning parts for motor vehicles and in house building.
The molded polyurethane products are produced by
introducing the foamable reaction mixture comprising an
organic polyisocyanate, a compound which contains at least
two hydrogen atoms that are reactive with isocyanates and
additives into closed molds which can be heated. The
reaction mixture foams up in the ~old and solidifies into a
highly compacted form. It substantially completely fills the
mold and accurately reproduces the internal surfaces of the
mold.
The molds are preferably made of a material with a
high thermal capacity and conductivity, preferably metal,
although other materials such as plastics, glass, wood, etc.
may also be used.
In order to prevent adherence of the plastics to the
surface of the mold on removal of the molded product, the mold
is treated with a mold release agent. Substances currently
used for this purpose include waxes, soaps or oils. These mold
LeA 15,511 ~
1~)5;~ 4
release agents form a thin film between the surface of the mold
and the plastics. The film prevents the molded product from
sticking to the mold so the product can be removed easily from
the mold.
This method has various disadvantages for production
of a series of products one after the other in the same mold.
The mold release agent must be applied to the mold wall at
regular intervals and during this time, the mold is not
available for production. Fine engravings on the mold, e.g.
a simulated wood structure or leather grain, become covered
with residues of mold release agent in the course of time.
Considerable effort is required to remove these firmly adhering
residues from the molds which frequently have a highly structured
surface. Furthermore, the molded product becomes covered with
a thin film of mold release agent which prevents the adherence
of lacquer or other coatings. The articles must therefore be
buffed or cleaned with solvents before they are lacquered in
order that the lacquer may adhere sufficiently firmly to the
molded product.
It is already known from German Offenlegungsschrift
No. 1,953,637 that the application of a mold release agent to
the mold can be dispensed with if the foamable reaction mixture
is mixed with certain additives which impart excellent mold
release properties to the finished plastics product so that it
can easily be removed from metal molds with its surfaces intact.
Salts which contain at least 25 carbon atoms obtained from
aliphatic carboxylic acids and amines, preferably primary amines
or amines which contain amide or ester groups, have been disclosed
as additives which have this effect.
In German Offenlegungsschrift No. 2,121,670, a process
has been disclosed for the production of foam plastics by
LeA 15,511 -2-
1~53424
foaming a reaction mixture of polyisocyanates, compounds which
contain reactive hydrogen atoms, water and/or organic blowing
agents and additives in a closed mold, in which the additives
used are, for example, a mixture of a) salts of aliphatic
carboxylic acids and amines which may contain amide and/or
ester groups, which salts contain at least 20 aliphatic carbon
atoms, and b) natural and/or synthetic oils, fats or waxes.
Since these additives have an internal lubricating
effect on the plastics mixture, they impart excellent flow
properties to the plastics material in the mold and reduce
the formation of bubbles on the surface of the plastics.
Furthermore, these internal mold release agents have an anti-
static effect and excellent mold release properties even in
metal molds with a highly structured surface.
Although excellent mold release effects can be obtained
by the known methods in rigid plastics, it is in practice
frequently found that the esters of higher fatty acids or their
mixed esters often used as snythetic oils or waxes are not
sufficiently effective mold release agents for producing special
elastomeric foam plastics.
The problem therefore arose of finding internal mold
release agents which would provide excellent mold release
properties for the production of polyurethane foams having a
cellular core and a dense outer skin which are elastomeric in
character.
It is therefore an object of this invention to provide
a process for molding foam plastics which is devoid of the fore-
going disadvantages. Another object of the invention is to
provide an improved process for molding polyurethane foams.
Still another object of the invention is to provide an improved
LeA 15,511 -3-
s~
release agent for use in molding polyurethane foams. A
further object of thè invention is to provide an improved
process f~r molding polyurethane foams having a dense skin
and a cellular core. A still furthex object for the invention
is to provide a foamable liquid composition adapted to react,
expand and solidify in a mold to substantially fill the mold
with a solid polyurethane foam which can be removed from the
mold without undesirable stic~ing of the molded foam to the
wall of the mold.
The foregoing objects and others are accomplished in
accordance with this invention, generally speaking, by
providing a foamable reaction mixture adapted to be molded
and containing an organic polyisocyanate and as an internal
mold release agent, a reaction product of ricinoleic acid and
a long chain fatty acid. The invention also provides a pro-
cess for molding the reaction mixture wherein the above foam-
able reaction mixture is charged to a suitable mold free
from mold release agent on its inner walls, the mold is closed
while the mixture reacts, expands and solidifies in the mold and
the resulting molded product is easily removed from the mold.
It has now surprisingly been found that the reaction
products of ricinoleic acid with long chain fatty acids alone
or in combination with other mold release agents or systems
provide excellent mold release effects in the production of
foams by the method of foaming in the mold and, moreover,
pxovide exceptionally good mold release properties in elas-
tomeric foam plastics.
This invention therefore provides a process for
producing a foam plastic which readily separates from the mold
in which it has been foamed wherein a foamable reaction mixture
containing an organic polyisocyanate, an organic compound hav-
ing a molecular weight of about 62 to about lO,000 which con-
tains reactive hydrogen atoms, a catalyst for the acceleration
LeA 15,511-Ca - 4 _
~(~5;~4
of the isocyanate/reaction hydrogen reaction, and a blowing
agent i5 charged to the mold and reacted, the improvement
which comprises adding to said active hydrogen containing
component or to the foamable reaction mixture as a third
stream an esterification reaction product of about 0.8 mol to
about 4 mols of ricinoleic acid and 1 mol of a long chain
fatty acid containing more than 8 carbon atoms which is sub-
stantially free of alcoholic hydroxyl groups, in an amount
sufficient to improve the mold release properties of the re-
sulting molded product.
The mold release effect may be determined subjectively
by manually opening a suitable mold and removing the molded
foam panel ~20 x 20 xl cm). The mold release forces required
for removing foam plastics which contain the reaction products
according to the invention are considerably lower than those
required for foams which are otherwise similar but which have
been obtained by foaming the reaction mixture without these
additives.
The foam plastics obtained by the process according to
the invention are primarily polyurethane foams known per se
which are produced by foaming in a mold, but the mold release
agents which are an essential feature of the invention can
be used e~ually advantageously when the process of foaming in
the mold is applied to the production of other polyisocyanate
based foams of the kind which can be obtained from polyiso-
cyanates alone or with the addition of organic compounds which
contain at least two Zerewitinoff active hydrogen atoms, e.g.
polycarbodiimide, polyisocyanurate, polyurea, polybiuret or
polyamide foams, mixed foams or other foams based on poly-
i~Qcyanates.
Any suitable organic polyisocyanate may be used as
a starting component according to the invention including ali-
phatic, cycloaliphatic, araliphatic, aromatic or heterocyclic
LeA 15,511-Ca - 5 -
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.
1053424
polyisocyanates of the kind which have been described e.g. by
W. Siefgen in Justus Liebigs Annalen der Chemie, 562, pages
75 to 136, for example ethylene diisocyanate; tetramethylene-l,
4-diisocyanate; hexamethylene-1,6-diisocyanate; dodecane-l,
12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-l,
3-diisocyanate; cyclohexane-1,4-diisocyanate and any mixtures
of these isomers; l-isocyanato-3,3,5-trimethyl-5-isocyanato-
methyl-cyclohexane (US Patent Specification No. 3,401,190);
hexahydrotolylene-2,4-diisocyanate, hexahydrotolylene-2,6-diiso-
cyanate and any mixtures of these isomers; hexahydrophenylene-l,
3-diisocyanate, hexa~.ydrophenylene-1,4-diisocyanate; perhydro-2,
4'-diphenylmethane-diisocyanate, perhydro-4,4'-diphenylmethane-
diisocyanate; phenylene-1,3-diisocyanate; phenylene-1,4-diiso-
cyanate; tolylene-2,4-diisocyanate; tolylene-2,6-diisocyanate
and any mixtures of these isomers; diphenylmethane-2,4'-diiso-
cyanate; diphenylmethane-4,4'-diisocyanate; naphthylene-1,5-
diisocyanate; triphenylmethane-4,4',4"-triisocyanate; poly-
phenyl-polymethylene po~yisocyanate which can be obtained by
aniline-formaldehyde condensation followed by phosgenation
and which have been described e.g. in British Patent Specifi-
cation Nos. 874,430 and 848,671; perchlorinated arylpoly-
isocyanates as described e.g. in US Patent Specification No.
3,277,138; polyisocyanates which contain carbodiimide groups
as described in US Patent Specification No. 3,152,162;
the diisocyanates described in U.S. Patent Specification No.
3,492,330; polyisocyanates which contain allophanate groups
as described e.g. in British Patent Specification No. 994,890;
Belgian Patent Specification No. 761,626 and published Dutch
Patent Application No. 7,102,524; polyisocyanates which contain
isocyanurate groups as described e.g. in US Patent Specification
No. 3,001,973, in German Patent Specification Nos. 1,022,789;
1,222,067 and 1,027,394 and German Offenlegungsschriften Nos.
LeA 15,511 -6-
10534Z4
1,929,034 and 2, 004,048; polyisocyanates which contain urethane
groups as described e.g. in Belgian Patent Specification No.
752,261 or US Patent Specification No. 3,394,164; polyisocyanates
which contain acylated urea groups according to German Patent Spe-
cification No. 1,2~0,778; polyisocyanates which contain biuret
groups as described e.g. in US Patent Specifications Nos.
3,124,605 and 3,201,372; British Patent Specification No. 889,050
and French Patent Specification No. 7,017,514; polyisocyanates pre-
pared by telomerization reactions as described e.g. in US Patent
Specification No. 3,654,106; polyisocyanates which contain ester
groups as described e.g. British Patent Specification No.
965,474 and 1,072,956; U.S. Patent Specification No. 3,567,763
and German Patent Specification No. 1,231,668 and reaction pro-
ducts of the above mentioned isocyanates with acetals according
to German Patent Specification No. 1,072,385.
Among the preferred polyisocyanates are also poly-
isocyanates which contain isocyanurate groups which isocyanurate
groups are formed in situ in the course of the process of the
invention by using polyisocyanate mixtures with catalysts that
accelerate the trimerization reaction of organic polyisocyanates.
These catalysts are known in the art and include e.g. organic
alkali salts such as for example potassium acetate, potassium
propionate, sodium acetate, sodium propionate or Mannich bases
such as disclosed in U.S. Patent 3,580,890 or British Patent
1,140,394 which are incorporated herein by reference. These
catalysts are normally used in amounts as disclosed in the
above patents.
The distillation residues which are obtained from the
commercial production of isocyanates and which still contain
isocyanate groups may also be used, optionally dissolved in
one or more of the above mentioned polyisocyanates. Any mixtures
LeA 15,511 -7-
lQ534'~4
of the above mentioned polyisocyanates may also be used.
It is generally preferred to use commercially readily
available polyisocyanates such as tolylene-2,4-diisocyanate
and tolylene-2,6-diisocyanate and any mixtures of these isomers
5 ( "TDI n ); polyphenyl-polymethylene-polyisocyanates which are
obtained by aniline-formaldehyde condensation followed by
phosgenation ("crude MDI") and polyisocyanates which contain
carbodiimide, urethane allophanate isocyanurate, urea or
biuret groups ("modified polyisocyanates").
For preparing the semi-rigid elastic foams which are
of particular interest in this invention, it is particularly
LeA 15~511 ~ -8-
1053424
preferred in the process according to the invention to use
modified aromatic diisocyanates and, in particular, derivatives
of diphenylmethane-4,4'-diisocyanate.
Examples of these particularly preferred polyiso-
cyanates include 4,4'-diphenylmethane-diisocyanate which
has been liquefied by partial carbodiimidization and the
"liquefied" 4,4'-diphenylmethane-diisocyanate which can be
obtained by reacting 1 mol of 4,4'-diphenylmethane-diisocyanate
with approximately a . 1 to 0.3 mol of a dipropylene glycol or
a polypropylene glycol which has a molecular weight of not more
than 700.
The starting components used according to the
invention may also include organic compounds having a molecular
weight of about 62 to about 10,000 which contain at least two
hydrogen atoms determinable by the Zerewitinoff method and
capable of reacting with isocyanates. These include not only
the compounds which contain amino, thiol or carboxyl groups
but particularly polyhydroxyl compounds, especially those
which contain 2 to 8 hydroxyl groups, more particularly those
with a molecular weight of about 200 to about 10,000, pre-
ferably about 1000 to about 6000, e.g. polyester, polyethers,
polythioethers, polyacetals, polycarbonates and polyester
amides which contain at least two, generally 2 to 8 but pre-
ferably 2 to 4 hydroxyl groups of the kind which are known
per se for the production of both homogeneous and cellular
polyurethanes. In the process according to the invention, it
is often advantageous to use the above mentioned higher mole-
cular weight polyhydroxyl compounds as a mixture with up to
95, preferably up to 50% by weight, based on the total quantity
of polyhydroxyl compounds, of low molecular weight polyols
with molecular weights of about 62 to about 200. Low molecular
LeA 15,511 -8a-
~053~24
weight polyols of this kind include e.g. ethylene glycol;
propane-1,2-diol; propane-1,3-diol; butane-1,2-diol; butane-l,
4-diol; hexane-1,6-diol; decane-l,10-diol; diethylene glycol;
triethylene glycol; tetraethylene glycol; dipropylene glycol;
tripropylene glycol; glycerol; trimethylolpropane and the like.
A foam made with a mixture of polyols of this type has a
density of 20-1100 kg/m3 and is elastomeric.
Any suitable polyester having hydroxyl groups may
be used including, for example, reaction products of polyhydric
alcohols, preferably dihydric alcohols to which trihydric alco-
hols may be added, and polybasic, preferably dibasic carboxylic
acids. Instead of the free polycarboxylic acids, the correspond-
ing polycarboxylic acid anhydrides or corresponding polycarboxy-
lic acid esters of lower alcohols or mixtures thereof may be
used for producing the polyesters. The polycarboxylic acids
used may be aliphatic, cycloaliphatic, aromatic and/or hetero-
cyclic and may be substituted, e.g. with halogen atoms, and/or
unsaturated. The following are examples: succinic acid; adipic
acid; suberic acid; azelzic acid; sebacic acid; phthalic acid;
isophthalic acid; trimellitic acid; phthalic acid anhydride;
tetrahydrophthalic acid anhydride; hexahydrophthalic acid an-
hydride; tetrachlorophthalic acid anhydride; endomethylene
tetrahydrophthalic acid anhydride; glutaric acid anhydride;
. maleic acid; maleic acid anhydride; fumaric acid; dimeric and
trimeric fatty acids such as oleic acid which may be mixed
with monomeric fatty acids; dimethylterephthalate and di-
ethylene terephthalate. Suitable polyhydric alcohols are e.g.
ethylene glycol; propylene-1,2-glycol; propylene-1,3-glycol;
butylene-1,4-glycol, butylene-2,3-glycol; hexane-1,6-diol;
octane-1,8-diol; neopentylglycol; cyclohexane dimethanol
(1,4-bis-hydroxymethylcyclohexane); 2-methyl-propane-1,3-diol;
glycerol; trimethylolpropane; hexane-1,2,6-triol; butane-1,2,
LeA 15,511 -9-
~053~24
4-triol; trimethylolethane; pentaerythritol; quinitol;
mannitol; sorbitol; methyl glycoside; diethylene glycol;
triethylene glycol; tetraethylene glycol; polyethylene glycols;
dipropylene glycol; polypropylene glycols; dibutylene glycol
and polybutylene glycols. The polyesters may also contain
some carboxyl end groups. Any suitable polyester of a lactone
such as E-caprolactone or hydroxycarboxylic acids such as
~-hydroxycaproic acid may also be used.
The polyethers used according to the invention
which contain at least 2, generally 2 to 8 and preferably 2
or 3 hydroxyl groups are also known per se and are prepared,
for example, by the polymerization of epoxides such as ethylene
oxide; propylene oxide; butylene oxide; tetrahydrofuran;
~tyrene or epichlorohydrin, each with itself, e.g. in the
presence of boron trifluoride or by the addition of these
epoxides, either as mixtures or successively, to starting
components which contain reactive hydrogen atoms such as
alcohols or amines, e.g. water, ethylene glycol, propylene-
1,3-glycol, propylene-1,2-glycol, trimethylolpropane, 4,4'-
dihydroxydiphenylpropane, aniline, ammonia, ethanolamine orethylene diamine. Sucrose polyethers such as those described,
for example, in German Auslegeschriften No. 1, 176,358 and
1,064,938 may also be used according to the invention. It is
in many cases preferred to use polyethers which contain pre-
dominantly primary hydroxyl groups (up to 90% by weight, based
on all the hydroxyl groups present in the polyether). Poly-
ethers which are modified with vinyl polymers are also suitable,
e.g. those obtained by the polymerization of styrene or acryl-
onitrile in the presence of polyethers (U.S. Patent Specifica-
tiGn No. 3,383,351; 3,304,273; 3,523,093 and 3,110,695 and
~erman Patent Specification No. 1,152,536), as well as poly-
butadienes which contain hydroxyl groups.
LeA 15,511 -10-
10534Z4
Any suitable polythioether may be used including
the condensation products of thiodiglycol with itself and/or
with other glycols; dicarboxylic acids; formaldehyde; amino-
carboxylic acids or aminoalcohols. The products obtained are
polythio mixed ethers; polythioether esters or polythioether
ester amides, depending on the cocomponents.
Any suitable polyacetal including, for example, the
compounds which can be prepared from glycols such as diethylene
glycol; triethylene glycol; 4,4'-dioxethoxy-diphenyl-dimethyl-
methane; hexane diol and formaldehyde may be used. Polyacetalssuitable for the purpose of the invention may also be prepared
by the polymerization of cyclic acetals.
Any suitable polycarbonate having hydroxyl groups may
be used. Such polycarbonates are also known per se, for example
those obtained by reacting diols such as propane-1,3-diol;
butane-1,4-diol and/or hexane-1,6-diol or diethylene glycol;
triethylene glycol or tetraethylene glycol with diarylcarbonates,
e.g. with diphenylcarbonate or phosgene.
Any suitable polyester amide or polyamide may be
used including e.g. thepredominately linear condensates which
can be obtained from polyvalent saturated and unsaturated
carboxylic acids or their anhydrides and polyvalent saturated
and unsaturated amino alcohols, diamines, polyamines and
mixtures thereof.
Polyhydroxyl compounds which already contain urethane
or urea groups and modified or unmodified natural polyols such
as castor oil, carbohydrates or starch may also be used.
Addition products of alkylene oxides and phenolformaldehyde
resins or urea-formaldehyde resins are also suitable for the
process according to the invention.
LeA 15,511 -11-
l~S3;~24
Representatives of these organic compounds having
reactive hydrogens which may be used according to the invention
have been described e.g. in High Polymers, Vol.XVI, "Polyurethanes,
Chemistry and Technology" by Saunders-Frisch, Interscience
Publishers, New York, London, Volume I, 1962, pages 32-42 and
pages 44-54 and Volume II, 1964, pages 5-6 and 198-199 and in
Kunststoff -Handbuch, Volume VII, Vieweg-Hochtlen, Carl-Hanser-
Verlag, Munich, 1966, e.g. on pages 45-71, the disclosures of
which are incorporated herein by reference.
For producing the semi-rigid elastomeric foams with a
dense outer skin which are of special interest in this in-
vention, it is particularly preferred to use difunctional poly-
hydroxyl compounds of the type mentioned above, optionally
mixed with up to 10 hydroxyl equivalent percent, based on the
total mixture of polyhydroxyl compounds, of the higher function-
al and in particular trifunctional polyhydroxyl compounds.
In the process according to the invention, the
reactants (including water which may be used as blowing agent)
are used in proportions which correspond to an isocyanate ratio
of 70 to 160 (an isocyanate ratio of 100 means that the reaction
mixture contains equivalent quantities of isocyanate groups and
active hydrogen atoms which enter into reaction with these
isocyanate groups). For producing the semi-rigid elastomeric
foams with dense outer skin which are of special interest in
this invention, the isocyanate ratio isgenerally between 90
and 110.
Any suitable blowing agent may be used. In many cases,
water and/or readily volatile organic substances are used as
blowing agents. Suitable organic blowing agents are e.g.
acetone;ethyl acetate; methanol; ethanol; halogenated alkanes
such as methylene chloride; chloroform; ethylidene chloride;
LeA 15,511 -12-
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vinylidene chloride; monofluorotrichloromethane; chlorodi-
fluoromethane or dichlorodifluoromethane or butane; hexane;
heptane or diethylether. Compounds which decompose at tem-
peratures above room temperature with the liberation of
bases, e.g. of nitrogen, for example azo compounds such as
azoisobutyric acid nitrile, may also act as blowing agents.
Other examples of blowing agents and details concerning the
use of blowing agents may be found in Kunststoff Handbuch,
Volume VII, published by Vieweg and Hochtlen, Carl-Hanser-
Verlag, Munich 1966, e.g. on pages 108 and 109,453 to 455
and 507 to 510.
Catalysts are often used in the process according to
the invention. Any suitable catalyst may be used in a catalytic
amount such as e.g. tertiary amines such as triethylamine,
tributylamine, N-methyl-morpholine; N-ethyl-morpholine; N-
cocomorpholine; N,N,N',N'-tetramethyl-ethylene diamine; 1,4-
diaza-bicyclo-(2,2,2)-octane; N-methyl-N'-dimethylaminoethyl-
piperazine; N,N-dimethylbenzylamine; bis-(N,N-diethylamino-
ethyl)-adipate; N,N-diethylbenzylamine; pentamethyldiethylenetri-
2Q amine; N,N-dimethylcyclohexylamine; N, N, N',N'-tetramethyl-1,3-
butanediamine; N,N-dimethyl-~-phenylethylamine, 1,2-dimethyl-
imidazole, 2-methylimidazole or the like.
Suitable tertiary amines catalysts which contain
hydrogen atoms which are reactive with isocyanate groups
include e.g. triethanolamine; triisopropanolamine; N-methyl-
diethanolamine; N-ethyl-diethanolamine; N,N-dimethyl-ethanol-
amine and their reaction products with alkylene oxides such as
propylene oxide and/or ethylene oxide.
Silaamines which contain carbon-silicon bonds may
also be used as a catalyst, e.g. those described in German
LeA 15,511-Ca -13-
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~Q53'~Z4
Patent Specification No. 1,229,290 such as 2,2,4-trimethyl-
2-silamorpholine and 1,3-diethylaminomethyl-tetramethyl-
disiloxane.
Bases which contain nitrogen such as tetraalkyl-
ammonium hydroxides alkali metal hydroxides such as sodium
hydroxide; alkali metal phenolate such as sodium phenolate
and alkali metal alcoholates such as sodium methylate are
also suitable catalysts. Hexahydrotriazines may also be used.
Organic metal compounds may also be used as catalysts
according to the invention, in particular organic tin compounds.
The organic tin compounds used are preferably tin (II)
salts of carboxylic acids such as tin (II) acetate; tin (II)
octoate; tin (II) ethylhexoate and tin (II) laurate and the
dialkyl tin salts of carboxylic acids such as dibutyl tin
diacetate, dibutyl tin dilaurate, dibutyl tin maleate, di-
octyl tin diacetate or the like.
Other examples of catalysts which may be used accord-
ing to the invention and the action of the catalysts have
been describedin Kunststoff-Handbuch, Volume VII, published
; 20 by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, e.g.
on pages 96 to 102.
The catalysts may be used in any catalytic amount,
usually in a quantity of between about 0.001~ and 10% by
weight, based on the weight of compounds having a molecular
~5 weight of about 62 to 10,000 which contain at least two
hydr~gen atoms which are reactive with isocyanates.
LeA 15,511- Ca -14-
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Conventional surface active additives (emulsifiers
and foam stabilizers) may also be used in the process according
to the invention, Suitable emulsifiers include e. g. the
sodium salts of ricinoleic sulphonates or of fatty acids or
salts of fatty acids with amines such as oleic acid diethyl-
amine or stearic acid diethanolamine. Alkali metal or ammonium
salts of sulphonic acids such as dodecylbenzene sulphonic acid
or dinaphthylmethane disulphonic acid or of fatty acids such
as ricinoleic acid or of polymeric fatty acids may also be
used as surface active additives.
Conventional foam stabilizers may be used such as
water-soluble polyether siloxanes. These compounds generally
have a polydimethylsiloxane group attached to a copolymer of
ethylene oxide and propylene oxide. Foam stabilizers of this
kind have been dèscribed e.g. in U.S. Patent ~peGific~ion
No. 3,629,3~8, the disclosure of which is incorporated herein
; by reference.
Reaction retarders, e.g. substances which are acid
in reaction such as hydrochloric acid or organic acid halides,
cell regulators known per se such as paraffins or fatty alco-
hols or dimethyl polysiloxanes, pigments, dyes and flame
retarding agents known Per se such as tris-chloroethyl phos-
phate or ammonium phosphate and polyphosphate, stabilizers
against ageing and weathering, plasticizers, fungistatic and
bacteriostatic substances and fillers such as barium sulphate,
kieselguhr, carbon black or whiting may also be used according
to the invention.
Further examples of surface active additives; foam
stabilizers; cell regulators; reaction retarders; stabilizers;
flame retarding substances; plasticizers; dyes; fillers and
fungistatic and bacterostatic substances which may also be
used according to the invention and details of the action and
LeA 15,511 -15-
lQ~i3~f~;~
method of using these additives may be found in Kunststoff-
Handbuch, Volume VI, published by Vieweg and Hochtlen, Carl-
Hanser-Verlag, Munich 1966, e.g. on pages 103 to 113.
In the process according to the invention, the foaming
is carried out in s suitable mold. The reaction mixture is
introduced into a mold made of a metal, e.g. aluminum or a
plastics material, e.g. an epoxide resin. The reaction mixture
foams up inside the mold to form the molded product. This
process of foaming in the mold may be carried out to produce
10 a molded product with a cellular structure on its surface or
it may be carried out to produce a molded product with a compact
skin and cellular core. According to the invention, these two
types of structure can be obtained by either introducing just
sufficient foamable reaction mixture into the mold to fill the
15 mold with foam or introducing a larger quantity of foamable
reaction mixture, in which case foaming is said to be carried
out under conditions of overcharging. This method of pro-
cedure has been disclosed, e.g. in U.S. Patent Specification Nos.
3,178,490 and 3,182,104.
Cold setting foams may also be produced according to
the invention (see British Patent Specification No. 1,162,517
and German Offenlegungsschrift No. 2,153,086).
In the process of foaming in the mold, the known mold
release agents may also be used in addition.
According to the invention, esters of ricinoleic acid
and long chain fatty acids are used as mold release agents.
Preferably, 0.8 to 4 mol, and most preferably 0.9 to 2 mol
of long chain fatty acid.
LeA 15,511-Ca -16-
J-~
l(~S3'~'~4
The long chain fatty acids used are preferably acids
with more than 8 carbon atoms and in particular, 12 to ~0 carbon
atoms and which are substantially free o~ alcoholic hydroxyl
groups. Although natural or synthetic dicarboxylic and poly-
carboxylic acids may also be used, it has been found most suit-
able to use natural monocarboxylic acids or natural fatty acid
mixtures, e.g. abietic acid, palmitic acid, stearic acid, oleic
acid, elaidic acid, linoleic acid, linolenic acid or fatty acid
mixture~ obtained from commercial processes, such as sperm oil
fatty acid, train oil fatty acid, tallow fatty acid, soya oil
fatty acid, palm kernel fatty acid, ground nut fatty acid, tall
oil fatty acid, and the like. The fatty acids or fatty acid
mixtures used are preferably liquid at room temperature, in
particular oleic acid and/or commercial fatty acid mixtures which
contain mainly oleic acid, for example soya oil fatty acid or
tall oil fatty acid.
Preparation of the esters of ricinoleic acid and long
chain fatty acids which are to be used in the process according
to the invention may be carried out by various methods known in
the art for producing esters. A simple method which has
proved to be particularly suitable comprises heating a mixture
of about 1 to 4 mols of ricinoleic acid with 1 mol ~or an
average of 1 mol determined by calculation) of the long chain
fatty acid to temperatures of up to 220C, preferably up to
170C, at reduced pressure, for example in the vacuum pro-
duced by a water jet pump, and drawing off the water liberated
in the reaction. The osmotically determined molecular weights
of the resulting esters are between about 500 and about 1800.
The esterification product which may be used directly as a
mold release agent may quite well still contain a certain
amount of products of side reactions in addition to unreacted
starting materials. The esterification reaction may accordingly
also be carried out with molar ratios outside the limits
LeA 15,511 -17-
1053~24
indicated above, i.e. with less or more than 1 mol of long
chain fatty acid and more or less than about 0.8 to 4 mols of
ricinoleic acid per mol of long chain fatty acid. The most
satisfactory results, however, are obtained within the molar
ratios given above.
Exceptionally good results are obtained when the
reaction is carried out with exclusion of air, e.g. in an
nitrogen or carbon dioxide atmosphere.
The reaction products used as mold release agents
according to the invention may be added as such to the starting
components used for producing the foam, e.g. to the polyol and/
or to the polyisocyanate. The mold release agents according
to the invention may be added to the starting components at room
temperature or they may be added at elevated temperatures, for
example to the polyisocyanates, so that they undergo a pre-
liminary reaction with the isocyanate by the so-called prepolymer
process. The new mold release agents are used in proportions
of 0.3 to 30% by weight, preferably 1 to 10% by weight, based
on the total quantity of reaction mixture.
The mold release agents to be used according to the
invention are suitable in principle for improving the removal
from the mold of any polyurethane foams, i.e. both soft, semi-
rigid and rigid foams known per se but it was found particularly
advantageous to use them according to the invention for pro-
ducing the semi-rigid polyurethane foams with compact outer
skin known E~r se by the process of foaming in the mold.
The foam formulations may, of course, also contain
other mold release agents or mold release systems, for,
example those described in German Offenlegungsschriften No.
1,953,637 and 2,121,670 or in Belgian Patent Speicifaction
LeA 15,511 -18-
~S3'~Z4
No. 782,942, e.g. the oleic acid salt or tall oil fatty acid
salt of the amine which contains amide groups obtained by
reacting N-dimethylaminopropylamine with oleic acid or tall
oil fatty acid.
Mold release agents of the kind described in British
Patent 1,420,293 and U.S. Patent 4,033,912 which are introduced
into the foam by way of modified isocyanates may also be used
as additional mold release agents.
According to the invention, the starting materials
may be reacted together by the known one-step, prepolymer or
semi-prepolymer process, often using mechanical devices such
as those described e.g. in U.S. Patent Reissue No. 24,514.
Details about processing apparatus which may be used in the
process according to the invention are given in Kunststoff-
Handbuch, Volume VI, published by Vieweg and Hochtlen, Karl-Hanser-
Verlag, Munich 1966, e.g. on pages 121 to 205.
Rigid foam products obtained by the process may be
used for the manufacture of furniture parts, parts of car
; bodies, technical apparatus and building elements while semi-
rigid to elastic foam products may be used for producing safety
cushioning in motor vehicles, elastic shoe soles, bumpers,
etc.
The process according to the invention will now be
described by way of example. The parts given are parts by
weight unless otherwise ind~cated.
LeA 15,511-Ca - 19 -
~053~'~4
Examples
Preparation of the reaction products of ricinoleic acid
and long chain fatty acids which are to be used as mold release
agents:
A:
Equal parts by weight of ricinoleic acid and oleic acid are
mixed with stirring under a layer of nitrogen and then heated
to 150C at a water column pressure of about 18 mm for 15 hours,
and the volatile constituents liberated are removed at the same
time by means of a distillation bridge.
The molecular weight determined osmotically in
toluene is found to be 680.
B:
The proceduxe is the same as described under A) but 2 parts
lS of ricinoleic acid and 1 part of oleic acid are used and
esterification is carried out for 20 hours. The molecular
weight found is 930.
C:
The procedure is the same as under A) but a commercial tall
oil fatty acid mixture is used instead of oleic acid. The
molecular weight is found to be 701.
D:
The procedure is the same as described under B) but instead
of oleic acid, a commercial mixture of soya oil fatty acid is
used. The molecular weight is found to be 1020.
LeA 15,511 -20-
~053~24
Example 1
100 Parts by weight of a polyol mixture with a hydroxyl number
of 276 and a viscosity of 730 cP at 25C. consisting of 90
parts by weight of a poly (alkylene ether) glycol with a
hydroxyl number of 28 which has been obtained by the addition
of a mixture of 80% of propylene oxide and 20% of ethylene
oxide to propylene glycol,
22 Parts by weight of butane-1,4-diol,
2 Part by weight of ethylene glycol,
0.1 Part by weight of water,
0.8 Part by weight of triethylene diamine,
0.08 Part by weight of dibutyl tin-IV-dilaurate,
4 Parts by weight of monofluorotrichloromethane,
2 Parts by weight of methylene chloride,
6 Parts by weight of "internal mold release
agent" according to Example A,
54 Parts by weight of polyisocyanate based on
diphenylmethane-4,4'-diisocyanate which has
an isocyanate content of 30.3% and which has
been liquified by a uretone-imine content of
15~ and which has been obtained by mixing at
about 80C about 1000 parts (4 mols) of 4,4'-
diphenylmethane diisocyanate with about 2.5
mol % of urea and heating the resulting mixture
at about 225C until said NCO-content has
been reached.
18 Parts by weight of a reaction product of 70
parts by weight of the polyisocyanate described
above and 30 parts by weight of polydimethyl-
siloxane with methylol end groups and a
hydroxyl number of 198, which reaction product
LeA 15,511 -21-
iioS3~24
has an isocyanate content of 16.5%.
~ he polyol mixture and mold release agent are mixed
with the isocyanate mixture by means of a two-component feeding
and mixing apparatus and the whole mixture is introduced into
a closed, tempered steel mold which is at a temperature of
60C. The plastics mixture begins to foam up after 12 seconds
and sets after a further 12 seconds.
The steel mold can easily be opened after 3 minutes
and the semi-rigid molded product can be removed without
adhering to the mold.
The molded product has an overall gross density of
0.80 g/cm3 and a material thickness of 10 mm with a compact
marginal zone which means a dense skin on both sides.
Example 2
100 Parts by weight of a polyol mixture with a hydroxyl number
of 276 and a viscosity of 730 cP at 25C. consisting of 90 Parts
by weight of a poly (alkylene ether) glycol with a hydroxyl
number of 28 which has been obtained by the addition of a mix-
ture of 80% propylene oxide and 20% of ethylene oxide to
20 propylene glycol,
22 Parts by weight of butane-1,4-diol,
1 Part by weight of ethylene glycol,
0.1 Part by weight of water,
0.8 Part by weight of triethylene diamine,
0.08 Part by weight of dibutyl tin-IV-dilaurate,
4 Parts by weight of monofluorotrichloromethane,
2 Parts by weight of methylene chloride,
6 Parts by weight of "internal mold release
agent", according to Example B and
54 Parts by ~eight of a polyisocyanate based on
diphenylmethane-4,4'-diisocyanate as
LeA 15,511 -22-
~053~;~4
described in Example 1.
18 Parts by weight of a reaction product of
70 parts by weight of the polyisocyanate
described above and 30 parts by weight of a
polymethylsiloxane with primary hydroxyl end
groups and a hydroxyl number of 198, which
reaction product has an isocyanate content of
16.5%-
The polyol and blowing agent are mixed with the
isocyanate mixture by means of a two-component feeding and
mixing apparatus and the whole mixture is introduced into a
closed, tempered steel mold which is at a temperature of 60C.
The plastics mixture begins to foam after 10 seconds
and sets after a further 8 seconds.
The steel mold can easily be opened after 3 minutes
and the semi-rigid molded product can be removed without any
part of it adhering to the mold.
The molded product has an overall gross density of
0.80 g/cm3 and a material thickness of 10 mm with a compact
marginal zone on both sides.
Example 3
100 Parts by weight of a polyol mixture with a hydroxyl number
of 276 and a viscosity of 730 cP at 25C. consisting of 90 Parts
by weight of a poly (alkylene ether) glycol with a hydroxyl num-
ber of 28 which has been obtained by the addition of a mixtureof 80% of propylene oxide and 20% of ethylene oxide to pro-
pylene glycol,
LeA 15,511 -23-
10534Z4
22 Parts by weight of butane-1,4-diol,
1 Part by weight of ethylene glycol,
0.1 Part by weight of water,
0.8 Part by weight of triethylenediamine
0.08 Part by weight of dibutyl tin-IV-dilaurate,
4 Parts by weight of monofluorotrichloromethane,
2 Parts by weight of methylene chloride,
; 6 Parts by weight of "internal mold release
agent" according to Example C;
64.5 Parts by weight of a polyisocyanate based on
diphenylmethane-4,4'-diisocyanate which
has been described in Example 1.
The polyol mixture and blowing agent are mixed with
the isocyanate by means of a two-component feeding and mixing
apparatu~ and the whole mixture i~ introduced into a closed,
tempered aluminum mold which is at a temperature of 60C.
The plastics mixture begins to foam after 8 seconds
and ~ets after a further 7 seconds.
The semi-rigid molded product can be removed from the
mold after 3 minutes without adhering to it.
It has an overall gross density of 0.80 g/cm and a
material thickness of 10 mm with a compact marginal zone on
both sides.
Example 4
100 Parts by weight of a polyol mixture with a hydroxyl number
of 550 and a viscosity of 1650 cP at 25C. consisting of 60
parts by weight of a poly (alkylene ether) polyol with a hydroxyl
number of 830 which has been obtained by the addition of propy-
lene oxide to trimethylolpropane, and
LeA 15,511 -24-
~053~'~4
Parts by weight of a poly (alkylene ether)
polyol with a hydroxyl number of 42, which
has been obtained by the addition of a mixture
of propylene oxide and ethylene oxide to a
mixture of trimethylolpropane and propylene
glycol (molar ratio 3:1),
1 Part by weight of a foam stabilizer as
disclosed in U.S. Patent 3,629,308,
column 12, lines 6-13,
0.6 Part by weight of tetramethylguanidine as
catalyst,
3 Parts by weight of dimethyl-benzylamine as
catalyst.
12 Parts by weight of monofluorotrichloromethane,
3 Parts by weight of an amidiamine oleic acid
salt (prepared from 1 mol of 3-dimethyl-
aminopropylamine-l and 2 mols of oleic acid),
; 6 Parts by weight of n internal mold release
; agent" according to Example A and
145 Parts by weight of a polyisocyanate which has
been prepared by phosgenating aniline-formal-
dehyde condensates and which has a viscosity
of 120 cP at 25C. and an NCO content of 31.5~,
which viscosity and NCO content has been
reached by distilling off dinuclear diisocyan-
ate from the phosgenation products.
The polyol mixture and blowing agent are mixed with the
isocyanate by means of a two-component feeding and mixing
apparatus and introduced into a closed, aluminum mold which is
at a temperature of 60C.
The plastics mix,ture begins to foam after 22 seconds
and sets after a further 18 seconds.
LeA 15,511 -25-
1C~53~Z4
The hard molded product can be removed from the
aluminum mold after 5 minutes. It lies loosely in the mold with-
out adhering to it at any point.
It has an overall gross density of 0.50 g/cm3 and a
mat~rial thickness of 10 mm with a compact marginal zone on both sides.
Example 5
100 Parts by weight of a polyol mixture with a hydroxyl number
of 276 and a viscosity of 730 cP at 25C. consisting of 90 Parts
by weight of a poly (alkylene ether) glycol with a hydroxyl
number of 28 which has been obtained by the addition of a
mixture of 80% of propylene oxide and 20% of ethylene oxide to
propylene glycol, and
22 Parts by weight of butane-1,4-diol,
1 Part by weight of ethylene glycol,
0.1 Part by weight of water,
0.8 Part by weight of triethylenediamine
0.08 Part by weight of dibutyl tin-IV-dilaurate,
4 Parts by weight of monofluorotrichloromethane,
2 Parts by weight of methylene chloride,
6 Parts by weight of "internal mold release
agent" according to Example D
64 Parts by weight of a semiprepolymer which has
been obtained by reacting 5 mols of diphenyl-
methane-4,4'-diisocyanate with 1 mol of tri-
propylene glycol and which has an isocyanate
content of 27%, and
21 Parts by weight of a reaction product of 70
parts by weight of a polyisocyanate based on
diphenylmethane-4,4'-diisocyanate which is
liquefied by its uretoneimine content of 15%
and 30 parts by weight of a polymethylsiloxane
with primary hydroxyl end groups and a hydroxyl
number of 198, which reaction product has an
LeA 15,511 -26-
53(~2~
isocyanate content of 16.5%.
The polyol mixture and blowing agent are mixed with
the isocyanate mixture by means of a two-component feeding
and mixing apparatus and the whole mixture is introduced into
a closed, tempered steel mold which is at a temperature of 60C.
The plastics mixture begins to foam up after 14
seconds and sets after a further 10 seconds.
The steel mold can easily be opened after 3 minutes
and the semi-rigid molded product can be removed from the mold
without adhering to it to any significant extent.
The molded product has an overall gross density of
0.80 g/cm3 and a material thickness of 10 mm with a compact
marginal zone on both sides.
Example 6
100 Parts by weight of a polyol mixture with a hydroxyl number
of 276 and a viscosity of 730 cP at 25C. consisting of 90 parts
by weight of a poly (alkylene ether) glycol with a hydroxyl
number of 28 which has been obtained by the addition of a mixture
of 80% propylene oxide and 20% of ethylene oxide to propylene
glycol,
22 Parts by weight of butane-1,4-diol,
1 Part by weight of ethylene glycol,
0.1 Part by weight of water,
0.8 Part by weight of triethylene diamine,
0.08 Part by weight of dibutyl tin-IV-dilaurate,
4 Parts by weight of monofluorotrichloromethane,
2 Parts by weight of methylene chloride,
6 Parts by weight of "internal mold release
agent" according to Example A,
54 Parts by weight of a polyisocyanate based on
diphenylmethane-4 r 4'-diisocyanate which has
LeA 15,511 -27-
1053424
be~n described in Example 1, and
18 Parts by weight of a reaction product (stirred
together for 3 hours at 100C) of 70 parts by
weight of the polyisocyanate described above
and 30 parts by weight of the "internal mold
release agent" according to Example A, which
reaction product has an NCO content of 16.8%.
The polyol mixture and blowing agent are mixed with
the isocyanate mixture in a two-component feeding and mixing
apparatus and the whole mixture is introduced into a closed,
tempered steel mold which is at a temperature of 60C.
The plastics mixture begins to foam up after 10
seconds and sets after a further 11 seconds.
The steel mold can easily be opened after 3 minutes
and the semi-rigid molded product can be removed without
adhering to it.
The molded product has an overall gross density of
0.80 g/cm3 and a material thickness of 10 mm with a compact
marginal zone on both sides.
2~ Any of the other mold release agents provided by the
invention may be substituted for those used in the foregoing
examples. As is apparant from the disclosure, this invention
contemplates broadly the foaming of all foamable compositions
which produce polyurethane foams and is not concerned with
the provision of any new organic polyisocyanates, polyols or
other conventional components of such a foamable reaction mix-
ture. The invention, on the other hand, provides a new mold
release compound for those heretofore known moldable foamable
mixtures.
LeA 15,511 -28-
1053~;~4
Although the invention has been described in detail
for the purpose of illustration, it is to be understood that
such detail is solely for that purpose and that variations
can be made therein by those skilled in the art without de-
parting from the spirit and scope of the invention except asit may be limited by the claims.
LeA 15,511 -29-
