Note: Descriptions are shown in the official language in which they were submitted.
6~)~
(1~573A~
(31.10.80)
POLYMER-MODIFIED POLYOLS USEF~ IN _ LYURETHANE
MA~UFACTURE
Th.is inven-tion relates to polymer-modified polyols
useful in polyurethane manufacture.
5. Polyurethane foam is manufactured by reac-ting a
polyol with a polyisocyana-te in the presence of a
blowing agent and usually also one or more other
additives.
In order to modify the physical properties of
10. the resulting foam in a desired manner, it is known
to use pre-formed polymer-modified polyols ~i.e.
polyols containing additional polymeric material) in
-~~ the po:Lyurethane-forming reaction. ThusJ for example,
British Patent 1,501,172 describes the use of polyol
15. dispersions of polyaddi-tion products of polyisocyanate
and primary amines, secondary amines, hydrazines or
hydrazides; and British Patent 1,482,213 describes the
use of polyols having dispe~sed therein and also
copolymerised therewith polymeric ma-terial derived
20- from the in situ polymerisation of ethylenically
unsaturated monomers. ..~
An object of the present invention is to provide
further polymer-modified polyols which may be useful
in polyurethane manufacture.
25. According to the invention thereEore there is
provided a method of forming a polymer-modified polyol
~,
~216~C~
(12573A) - 2 -
~11.11.80)
wherein an olamine is polymerised with an organic
polyisocyanate in the presence of a polyol, the
olamine reacting at least predominantly polyfunct-
ionally with the isocyanate.
5- With the method of the :Lnvention, the olamine
(by which is meant an organic compound having one or
more hydroxyl (-OH) groups and also one or more amine
groups whether primary, secondary or -tertiary
(-NH2,=NH,~N) acts as a polyfunctional reactant
10. (having two or more reactive hvdrogens) and a poly-
addition product is formed with the polyisocyanate
(by which is meant a compound having two or more
isocyanate groups). Where the olamine is a primary
~ ~ .
or ~econdary amine, it has alcohol and amine groups
15. with active hydrogens all of which hydrogens may be
reactive with regard to the isocyanate. Where the
olamine is a tertiary amine it has multiple alcohol
groups with active hydrogens all of which may be
reactive with regard to the isocyanate. In each case
20. all or only some of the reactive hydrogens may iII fact
react. It is believed that the polyaddition reaction
produces straight and/or branched chains by combination
of isocyanate and hydroxyl groups to form urethane
linkages (-NH-CO-O-) and by combination of isocyanate
25. and amine groups to form urea linkages (-NH-CO-NH- or
=N-CO-NH-) as appropriate. The said polyaddition
product may be mixed and/or chemically combined (as
(12573A) ~ 3 ~
(31.10.80)
by copolymerisat.ion) with the polyol and it is to
be understood that the term polymer-modified polyol
as used herein is intended to encompass both physical
and chemical combinations and also mixtures thereof,
5~ although it is believed that, most usually, the method
of the invention will result in a predominantly
physical combination. Such physical combination
may be in the form of a solution or a stable dis-
persion of the polyaddition product in the polyol
10. depending on the starting materials used. In particular,
the choice of the olamine and possibly also the
polyol may determine the physical state of the
polymer--modified polyol.
~-~ Most preferably, with the method of the invention,
15. the olamine and the isocyanate are mixed in the molar
ratio of about 1.0/0.5 to 1.0/1.5 in the presence of
a polye~her polyol having a molecular weight in the
range 200 to 10,000 ~particularly 2800-7000) and the
reacted olamlne and polyisocyanate together constitute
20. 1~ to 35~ by weight based on the weight of the polyol.
Any suitable alkanolamine or combination of
alkanolamines may be used as the olamine of the present
invention including but not restricted to primary,
secondary and tertiary al]canolamines such as
25. Monoethanolamine, diethanolaniine, triethanolamine,
N-Methylethanolamine~ N-Ethylethanolamine, N-Butyl-
~1~2~
(12573A~(31.10.~o
ethanolamine~ N-Methyldiethanolamine, N-Ethyldie-thano-
lamine, N-Butyldiethanolamine, ~onoisopropanolamine,
Diisopropanolamine~ Triisopropanolamine, N-Methyl-
isopropanolamine, N-Ethylisopropanolamine, N-Propyl-
5- isopropanolamine. The term alkanolamine as used
herein includes substituted alkanolamines and, for
example, it is also possible to use primary and
secondary alkanolamineswhich are halogen substituted
at the nitrogen atom, or secondary or tertiary alkano-
10. lamines which are halogen substituted at the alkylgroup (i.e. the alcohol group replaced by a halogen atom).
In a particularly preferred embodiment, triethanolamine
is used as the alkanolamine.
Whilst it is visualised that the method of the
15. present invention will most usually utilise an alkano-
lamine, particularly an open chain aliphatic alkano-
lamine, as the olamine it is to be lmderstood that
it may also be possible to use other olamine compounds
which have hydroxyl and amine groups attached to
20. carbo-cyclic, aromatic or heterocyclic nuclei or
combinat,ons thereof with each other and/or with open
chain aliphatic nuclei.
Any suitable organic polyisocyanate may be used
including aliphatic, cycloaliphatic, araliphatic,
25. aromatic a~d heterocyclic polyisocyanates such as are
known for use in the polyisocyanate/polyol polyurethane
.
z~
(12573~) - 5
(31.10.80)
forming reac-tion (see for example British Patent No.
1,453,2~
Suitable commercially readily available polyiso-
cyanates include 2,4 and 2,6 tolylene diisocyanates
5- al~o mixtures of these isomers (called in general TDI3,
polyphenyl polymethylene pol.yisocyanates of the type
obtained by condensing aniline with formaldehyde, foll-
owed by phosgenation (called in general crude MDI), and
polyisocyanates containing carbodiimide groups, urethane
10. groups, allophonate groups, isocyanate groups, urea
groups or biuret groups (called in general polyisocyanates~.
Any suitable polyol may be used including polyether
polyols having a molecular weight in the range of 200
.. .. .
to 10,000 such as are known for use in the polyisocyanate/
15. polyol polyurethane forming reaction and as described for
example in British Patent No. 1,482,213. Such known
polyether polyols can be obtained by reaction of
alk~lene oxides with active hydrogen containing
. compounds, the molecular weight of the reaction product
20. depending on the amount of alkylene oxide reacted.
The polyaddition products obtained according to
the present invention may be modified by the propor
tionate use of monofunctional isocyanates, amines or
N-dialkylalkanolamines. For example, the average
25. molecular weight of the polyaddition products may be
adjusted by incorporating monoEunctional compounds of this
(12573A) - 6 -
(11.11.80)
type in proportions of up to 25 mole percent based
upon the olamine component~
Suitable monofunctional isocyanates include methyl,
ethyl, isopropyl, isobutyl/ hexyl~ lauryl, and stearyl
5. isocyanate, cyclohexyl isocyanate, phenyl isocyanate,
tolylisocyanate 4-chlorophenyl isocyanate and diiso-
propyl phenyl isocyanate.
Suitable monofunctional amines include dialkyl-
- amines such as dimethylamine, diethylamine, dibutylamine,
10. cyclohexylamine, and suitable N~dialkylalkanolamines
include dimethylethanolamine and diethvlethanol~mine.
It is to be unders-tood that not all aleohol/amine
groups of the olamine used in the polyaddition reaction
- of the invention need react in all circumstances with
15. the isocyanate and thus the olamine may react mono-
functionally in some instances thereby to act in
itself as a ehain terminator.
If desired, the polyaddition reaction of the
present invention can be catalysed by introduction
20. of substances such as those conven-tionally used as
catalysts in the polyisocyanate/polyol polyurethane
forming reaction. Thus organometallics such as stannous
oetoate and dibutyl tin dilaurate and/or amines such
as triethylenediamine can be used. The amount of
25. catalyst used may be small in relation -to that normally
(12573A) - 7 -
(31.10.80)
used in the polyurethane forming reaction, for example
of the order of 0~02% rat.her than 0.2% of the total
weight of polyol~ although laryer amounts may also be
used if desired.
5- The reaction us.ing a primary or secondary alkan-
olamine may not require ca~alysis bu-t this may be
advantageous with a tertiary alkanolamine such as tri-
ethanolamine.
The molecular weight of the polyaddition product
10. may be adjusted by varying the quantitative ratio
between the olamine on the one hand and the poly-
isocyanate on the other hand (and by monofunctional
components ie t:hey are used~. Thus, for example,
although a molar ratio of olamine to polyisocyanate
15. of 1.0/0.5 to 1.0/1.5 is preferred and substantially
equivalent molar quantities are particularly preferred,
it is possible to use a higher proportion of
isocyanate if appropriate allowance can be made for
the higher viscosity or even rapid gellation which
20. tends to occur at higher isocyanate levels. An upper
ratio of say 1.0/1.55 or 1.0/1.6 may thus be possible.
As the quantity of isocyanate is reduced the
molecular weight of the polyaddition product also
decreases together with the viscosity. In general
25- an olamine/organic polyisocyanate molar ratio of
1.0/0.8 to 1.0/1.1 is preferred.
iQq~
(12573A) - 8 -
(31.10.80)
It ls even possible substantially to exceed the
above rnentioned upper ratio limit of 1 to 1.6 if a
"eapping" agent is introduced to limit cross-7inking
and hence gellation. Thus, although it may normally
5. be preferable to utilise reaction conditions whieh
result in bifunctional reaction of the olamine with
the isocyanate, in some circumstances and with some
olamines, particularly triethanolamine, it may be
preferable to obtain trifunetional reaction of the
10. olamine with the isocyanate thereby to ensure that
there are substantially no free hydroxyl groups whieh
eould undesirably interfere with a subsequent poly-
.-i urethane-Eorming reaction using the polymer-modified
polyol. In this latter ease an olamine/isoeyanate
15. ratio of up to say 1.0/2.1 or higher may be desirable
and a capping agent (say N-dimethylethanolamine) may
be added (say in an olamine/capping agent ratio of
1.0jl.2) to limit cross-linking~
Although the concentration of the reacted olamine
20. and isocyanate (and henee the polyaddition produc-ts)
in the polyether po~.yol may vary within wide limits
it should generally be between 1 and 35% by weight,
preferably from 3 to 30% by weight. Where a speeifie
eoncentration of polyaddltion product is required
25. (f.or.example for use in the manufaeture of polyurethane
foams having certain optimal properties a eoneentration
~12573A) 9 ~
(11.11.8~)
of about 10-o by weight may be required) this may he
obtained di.rectly by appropriate selection of the
reac-tants to give the required concentration or alter-
natively by subsequent dilution of a formed polyaddition
-S. product with additional polyether polyol as appropriate.
In general the reactants may be mixed at
temperatures from 0C, or above thei.r meltiny points,
whichever may be lower~ up to 150C. Preferably the
reactants are mixed at room temperature or just above
10. their melting points, whichever may be lower, up to 70C.
It may also be possible to mix the reactants below
their melting points.
The reaction is exothermic and a temperature rise
.,
is observed according to the proportion of polyaddition
15. product made, based upon the weight of the polyether
polyol.
The more efficient the mixin~ of the reactants
the finer the particle size of the d.ispersion (where a
dispersion is produced) and the lower the viscosityO
20. Although a si.mple batch process may be used, whereby
one of the olamine and polyisocyanate reactants is
first of all dissolved or dispersed in the polyether
polyol, followed by addition of the other into the zone
of maximum agitation, in-line blending of the
25, materials may also be used, In the latter case all
reactants are pumped at controlled rates and may
~326~
~12573A) - 10 -
(31.10.80~
be mixed simultaneously or one reactant may be mixed
firstly with the polyether polyol followed by addition
and mixing of the other reactant.
The dispersion in polyether polyol may be used
S. either immediately after completion of the reaction
or after a prolonged period oE time. For example,
the polyaddition product in a polyether polyol may be
metered from an in-line blending unit, where the
reaction takes place, directly into the mixing head
10. of a polyurethane production machine, of a well-known
type. Where the reaction of the olamine with the
polyisocyanate is relatively slow, then an inter-
mediate holding tank may be used between such in-line
blending unit and the polyurethane mixing heàd to
15. allow additional time for complete reaction to take
place.
Additives such as activators, stabilizers, cross-
linkers, waterr blowing agents, flame-proofing agents
and pigment pastes, may be added to the polymer-
20. modified polyol of the presen-t invention either durin~
or after reaction.
The polyaddition product of the present invention
can be used in the manufacture of polyurethane foam.
In the case where the product is in the form of a
25. stable polyol dispersion, that is a dispersion which
does not settle out or at least will remain in dis-
(12573A) ~ 11 ~(31.10.80)
persion during mixing with o-ther foam~forming ingred-
ients, the dispersed polyaddition product is par-t-
icularly effective as a polymeric filler in the
production of highly resilient conveniently processible
5. foam, such dispersed product acting to build strength
whilst at the same time rupturing cell walls.
In the case where the product is in the form
of a polyol solution, this may be suitable for the use
in forming polymeric material having properties
10. different from those obtained with polyol dispersions.
In general, where the polyaddition product is
in the form of a stable dispersion, this is suitable
for processing into soft, semi-hard and hard poly-
~.
urethane foams having improved properties, such as
15. increased hardness, and non-shrinking foams o~ the high
resilience type which are well-known in the industry,
can be prepared since the polyol dispersed polyaddition
product has a cell opening effect. In addition the
dispersions are also suitable for the production of
20. for example elastomers, coverings and coatings based
on polyurethanes.
Where the dispersion is to be used in making a
polyurethane, usually the polyurethane forming process will
utilise the polyol of the dispersion and thus the
25. properties of the polyol of the dispersion, part-
icularly its h,droxyl number and functionality, will
(12~73A) - 12 -
(31.10.80)
be selected in known manner in dependence upon the
type of polyurethane being made. For exampl~ for
the preparation of elastomers the polyether polyol
will preEerably be predominantly linear, i.e. di-
5- functional and will have hyclroxyl numbers in the range
30 to 170. For the preparation of foams, the polyether
po]yols are selected in known manner to give foams
which are flexible, semi-flexible or rigid. Thus for
the preparation of flexible foams the polyether polyols
10. preferably have hydroxyl numbers in the range 20 to 80
and from 2 to 4 hydroxyl groups per molecule for example
ICI Polyol P~A 1233. If desired mixtures of polyether
polyols can be used.
- Organic polyisocyanates which may be used in making
15. the polyurethanes have been described in the prior
art and may ~e the same as the oxganic polyisocyanates
described above for reaction with the olamine.
The polyurethane foaming reaction mixture may
also contain other conventional ingredients of such
20. reaction mixture according to the type of polyurethane
being made. Thus~ the reaction mixture may contain
catalys-t, for example tertiary amines and organic tin
compounds, cross-linking or chain lengthening agen-ts,
for example diethanolamine, triethanolamine, ethylene
25. glycol, glycerol, dipropylene glycol and phenylene
diamine, ~lame-proofing agents, for example halogenated
(12573A) - 13 -
(31.10.~
alkyl phosphates and fillers Eor example barium
sulphate.
For the preparation of Eoams, blowing agents are
included in the reaction mixture. Examples of
5. suitable blowing agents include water which reacts
with the polyisocyanate forming carbon dioxide and
inert volatile liquids which vapourise under the
influence of the exothermic reaction or due to the
release of pressure if a mechanical frothing process
10. is use~. Examples of such liquids are halogenated
h~drocarbons having boiling points not exceeding 100C
at atmospheric pressure and preferably not exceeding
50 C, especially chlorofluorinated hydrocarbons such as
trichlorofluoromethane and dichlorodifluoromethane
15. also chlorinated hydrocarbons such as dichloromethane.
The amount of blowing agent is selected in known manner
to provide foams of the desired density. In general -
from Q.005 to 0.3 mole of gas per 100 grams of reaction
mixture is suitable. If desired, the density of the
20. foam produced can be modified by over-packing, that is
to say foaming the reaction mixture in a closed mould
having a volume less than that which would be occupied
by the resultant foam if the reaction mixture were
allowed to rise freely.
25. In general, the composition of the polyure-thane-
forming reaction mixture should be such that the ratio
(12573~) - 14 -
(31.10.80)
of isocyanate groups to active hydrogen atoms is sub-
stantially within the range 0~9/1 to 1~2/1 but
higher ratios may be used if desired.
When a polyurethane foam is prepared it is usually
5, necessary to stabili2e or regulate the cells which
are formed by the addition oE a foam stabilizer or
cell regulakor such as polysiloxane - polyalkylene
oxide block copolymers which may contain direct carbon
to silicon or carbon to oxygen to silicon bonds between
10. the organic and polysiloxane units. When producing
'high resilience' polyurethane foams then dimethyl
silicone oils or low molecular weight modifications
thereoE are satisfactory, for example Theodore
Goldschmidt ~G silicone B8616.
15. One shot, prepolymer or quasi prepolymer methods
may be empIoyed as may be appropriate for the par-ticular
type of polyure-thane being made.
The components of the polyurethane forming reaction
mixture may be mixed together in any convenient manner,
20. for example by using any of the mixing equipment
described in the prior art for the purpose. If desired,
some of the individual components may be pre-blended
so as to reduce the number of component streams requiring
to be brought together in the final mixing step. It
25. is often convenient to have a two-s-tream sys-tem whereby
one stream comprises a polyisocyanate or prepolymer
(12573~ 5
~ 11.80)
and the second stream comprises all the other com-
ponents of the reaction mix-ture.
The invention is illustrated but not limited by
the following Examples in which all parts are by weight
5. and percentages by weight. Unless otherwise stated
ambient temperatures were used for reactants.
The abbreviations used in the Examples for the
polyethers have the followiny meanings.
Polyether A:
- 10. A glycerol-started polyether of propylene oxide
tipped with 15% ethylene oxide to an hydroxyl number
of 35 and a primary hydroxyl number of approximately
- 75%.
Polyether B:
15. A trimethylol propane-started polyether of propylene
oxide tipped with ethylene oxide to an OH number of
34 and a primary OH group content o~ approximately 80%.
Po~ether C_ -
A glycerol~started polyether of propylene oxide
20. and ethylene oxide to an OH number of 47 and a primary
OH group content of less than 5%.
Po~ether D.
A linear polypropylene glycol with an OH number of
56 containing secondary hydroxyl groups.
25. Example 1
9oO gms. of polyether A a-t a temperature of 20C
(12573A) - 16 -
(3~.10.80)
was blended with 48.7 gms. of -triethanolamine at a
temperature of 20C under conditions of high speed
mixing 51.2 gms. of a mixture of 80% 2.4 and 20~
2.6 tolylene diisocyanate was added over a period of
5. five seconds. 0.3 gms. of dibutyl-tin-dilaurate
catalyst was then added and a fast reaction took place
and the temperature of the mixture rose from 20C to
37C over a period of three minutes from the time of
completion of addition of the catalyst.
10. On cooling the resulting stable dispersion with
10-~ solids had a viscosity of 1600 cps. at 25C.
300 gms. of the above product was placed in a
beaker followed by 7.8 gms. of water, 3 gms. of
diethanolamine, 0.21 gms. of bis (2 dimethyl aminoethyl)
15. ether and 1.5 gms. of Goldschmidt Silicone B8616 and
stirred, the temperature being adjusted to 22C. Next
was added 0.75 gmsO of dibutyl-tin-dilaurate and -
stirred for 10 seconds followed by the addition of 117
gms, of a mixture of 80% of 2.4 and 20~ of 2.6 tolylene
20. diisocyanate. After a further five seconds the
mixture was poured into a box and expansion started.
After a further 105 seconds from the end of mixing
a non-shrinking 'high resilience' foam had been
produced with the following proper-ties.
25. Density Kgs./m 34
CLD g/cm (1) 28
Resilience %(2) 63
3;~
(12573A) - 17 -
(31.10.80)
(1) Resistance to a compression at 40% deflec-tionO
~2) Ball rebound %.
Example 2
920 gms. of polyether ~ at 20C were added to a
5. beaker and 32.1 gms. oE diethanolamine at 30C was
added at room temperature with mechanical stirring.
47.9 gms. of a mixture of 80% of 2.4 and 20% of 2.6
tolylene diisocyana-te were aclded over a period oE
30 seconds into the vortex of the stirred mixture.
10. A white stable dispe~sion was formed and the temperature
had risen from 20C to 37C within 30 seconds of
completion of the addition of the isocyanate. The poly-
addition product contained the isocyanate and alkan-
olamine in the molar ratio of 0.9 to 1.0 and the final
15. product contained 8.0% of the polyaddition product in
polyether polyol and had an acceptable viscosity at
ambient temperature.
300 ~ms. of the above product was placed in a
beaker followed by 7.8 gms. of water, 3 gms. of
20. diethanolamine, 0.21 gms. of bis (2 dimethyl aminoethyl)
ether and 1.5 gms. of Goldschmidt Silicone B8616 and
stirred, the temperature being adjusted to 22C.
Next was added 0.75 gms. of dibutyl-tin-dilaurate and
stirred for 10 seconds followed by the addition of
25. 117 glns. of a mixture of 80% oE 2.4 and 20% of 2.6
to]ylene diisocyanate. After a further five seconds
~8;~
(12573A) - 18 -
(11.11.80)
the mixture was poured into a box and expansion s-tarted.
After a further 105 seconds from the end of mixing
a non-shrinking 'high resilience' Eoam had been
produced with properties similar to Example 1.
5~ Example 3
A foam was prepared accordi~g to the method as
described in Example 2 except that 300 gms. of the poly-
addition product in polyether polyol was replaced by
- 300 gms. of the polyether polyol (polyether A) and
10. only 100 gms. of the isocyanate was used~ Expansion
to produce a foam took place as in Example 2 except
that the resulting foam shrank, the properties being
unmeasurable.
- - Example 4
15. The polyaddition product in polyether polyol was
prepared using polyether A according to Example 2 and
was foamed also according to Example 2 except that
all of the dibutyl-t~n dilaurate was replaced by 0.6
gms. of stannous octoate. A non-shrinking foam was
20. obtained of the hi~h resilience type with properties
similar to those of Example 1.
Example 5
-
A polyaddi-tion product was prepared and foamed
according to Example 2 except that the polyether A was
25. replaced with polyether B. The stable dispersion in
polyether polyol had a solids content of 8~ and an
(12573A) 19 -
(11.11.80)
acceptable viscosity of ambient temperature. The
resulting foam was non-shrinking and had properties
similar to those of Example 1.
5. A polyaddition produc-t in polyether A was prepared
according to Example 2 except that the molar ratio of
isocyanate to alkanolamine was 1.1 to 1.0, the total
solids content remaining at 8%. The resulting product
had a high but usable viscosity in excess of 2500 cps.
10. at 25C. Foaming according to Example 2 gave a high
resilience non-shrinking foam.
Exam~e 7
A polyaddition product in polyether A was prepared
according to Example 2 except that the molar ratio of
15. isocyanate to alkanolamine was 0.45 to 1.0 and the
total solids co~tent was 8%. Foaming according to
Example 2 gave a shrinking foam. The properties of this
foam could not be measured.
20. A polyaddition product was produced by takin~
920 gms. of polyether A at a temperature of 20C and
mixing with 24.5 gms. diethanolamine at a temperature
of 30C followed by 55.5 gms. of crude MDI wi-th
vigorous agitation. A polyaddition product in a poly-
25. ether polyol was obtained having a solids content of
8~ and a usable but high viscosity in excess of
tl2573~) - 20 -
(11.11.80)
3000 cps. ~t 25C.
The product was foamed according to Example 2
giving a non-shrinking foam of the high resilience
type.
50 Example g
A stable dispersion in polyether C at a temperature
of 20C was prepared by ta]cing 800 gms. of polyether
C and adding 80.24 gms~ of diethanolamine at a temp-
erature of 30C which was stirred at high speed prior
10. to and during ~he addition of 119.75 gms. of a mixture
of 80% 2,4 and 20% 2,6 tolylene diisocyanate which
took place over a period of one minute. A temperature
rise of 29C was observed and the product on cooling
, ~
had an acceptable viscosity at ambient temperature and
15. a solids content of 20%.
Example 10.
A stable dispersion was prepared according to
Example 9 except that polyether C was replaced by
polyether D. The resulting polyaddition compound in
20. polyether D had a solids content of 20% and an acceptable
viscosity at ambient temperature.
The stable dispersion produced in accordance with
the foregoing Examples 1, 2, 5-10 are of a non-ionic
nature. That is, the dispersions contain covalent
25. polymeric subs~ances which are devoid of ionic groups.
Moreover, substantially no water or other ionic
(12573A) - 21 -
(26.1.~1)
medium is used in the prcpara-tion of (nor is present
in) the dispersions~ ~n this latter respect the
presence of traces of water, such as will tend to be
contained in colNnercially available polyols and other
5. starting materials, may be accep-table although in
general the presence of water is undesirable and should
be kept at as low a level as possi~le. Preferably
the water conten~ should not be greater than 1% by
weight and most preferably the content is very much
. 10. less than this, say below 0.1%, although it is to be
understood that in some circumstances it may be possible
to operate the process of the invention at water
levels above 1%.
. .
The polyols used in performing the process of the
15. invention may be of the triol kind containing pre-
dominantly primary hydroxyl groups in so far as such
polyols are of particular use as starting materials
for the formation of polyurethane foams. However,
since the production of polymer-modified polyols in
20. accordanc~ with the process of the invention, and
particularly the production dispersions as described
in the above Examples, involves reaction of the iso
cyanate wholly or predominantly with the olamine with
. the polyol acting wholly or predominantly as an
25. unreactecl carrier, i~ will be appreciated that it is
possible to use any suitable polyol selected in
~12573~) - 22 -
(26.1.81)
par-ticular in accordance with -the requirements of a
subsequellt polyurethane-forming reacti.on in which the
polymer-modified polyol is to be used. Thus for
example polyols which are triols and/or d.iols and which
5. have primary and/or secondary hydroxyl groups or any
other suitable structures may be used.
