Note: Descriptions are shown in the official language in which they were submitted.
1046197
~ his invention relates to a novel process of preparing
vesiculated polyester resin granules.
It has been proposed that granules of vesiculated
polymer with diameters of~the order of 0.5 to 500 micron be
used as matting and texturing agents in paints and plastics
and as fillers in paper. Granules of this general type are
described in, for example, Aus~ralian patent specification
No.439,4~2, in which it is further disclosed that the ratio
of granule diameter to vesicle diameter should be at least
5/1
Australian patent specification ~o. 455,277 discloses
that useful vesiculated cross-linked polyester resin
granules can be prepared from selected carboxylated
~ saturated polyester resins by-a process which involves
the emulsification of an unsaturated monomer, for example
styrene, in water in the presence of a strong base,
followed by curing of the resin~ Particles of pigment
can be incorporated in the granules by first pigmenting
the polyester resin solution and by a double-emulsion
technique, in which a dispersion of the pigment in water
is first suspended in droplet form within the unsaturated
polyester resin solution. That suspension in turn is
dispersed in bead form in water.
~he beads are stabilised by the presence of a water-
soluble polymer, for example a partially hydrolysed poly(vinyl acetate), in the external water phase.
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1046197
Curing of the unsaturated polyester resin is initiated
in conventional manner, e.g. by the use of free-radicle
initiators. ~he resultant product is an aqueous slurr~
of vesiculated cross-linked polyester resin granules.
While vesiculated granules in the form of aqueou~
~lurries may be well suited to direct incorporation
into a~ueous products, for example aqueous latex paints~
without first extracting and drying the granules, this
step clearly cannot be avoided when preparing non-
aqueous end products. ~he presence of water-soluble
polymeric stabiliser or protective colloid in the
slurries can introduce undesirable economic and technical
complications into the extraction and drying process,
so that when anhydrous granules are required it would be
desirable to eliminate or drastically reduce the use of
such a water-soluble polymeric component.
We have now discovered a process of preparing
vesiculated polye3ter resin granules whereby certain
of the existing limitations of known processes can be
avoided. ~he granules so-prepared have certain important
and surprising advantages over vesiculated polyeqter
resin granules hitherto known to the art.
~ he process we now disclose involves the use of an
unsaturated pol~ester resin in which is incorporated
chains of poly(ethylene oxide). ~his resin co-reacts
in known manner with ethylenically unsaturated monomer.
Furthermore, a solution of the resin in ethylenicall~ -
-- 3 --
- 1~46~97
unsaturated monomer on agitation with water forms a
self-stabilised globular dispersion of the resin solution
in water and the individual globules spontaneously
acquire a vesiculated structure.
Accordingly we now provide a process of preparing
an aqueous ~lurry of ve~iculated polyester re~in granule~
by stirring into water a solution of an unsaturated
polyester resin in ethylenically unsaturated monomer
to form a dispersion in the water of globule~ of the
unsaturated polyester resin solution and then adding to
the dispersion a free radicle initiator to i n; tiate co-
reaction of the unsaturated monomer, the process being
further characterised in that;
(1) the polyester resin shall comprise from
2-50% by weight of poly(ethylene oxide)
chain~ of average molecu~.ar weighb
1000 - 10~000 which are water soluble at
the granule processing temperature and
(2) the ethylenically unsaturated monomer shall
have a solubility of less than 5% by weight
i~ water.
~he polyester resin granules may be separated
from the water of the slurry and dried.
Unsaturated polyester resins which co-react with
eth~lenicall~ unsaturated monomer to give a cross-
linked polymer structure are? as a class, well know~
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- 1~46197
to the art, as are ways of initiating the polymerisation
reaction. ~he most widely recognised t~pe of unsaturated
polyester resin is the condensation reaction product of
polyols and polybasic agids, at least a portion of which
acid is ethylenically u~saturated, for example ethylene
glycol reacted with maleic acid or acid anhydride. A
resin of this type will normally contain unreacted
carboxyl groups, the concentration of which is expressed
as the acid value of the resin, in units of mgm EOE
equivalent to one gm of the resin.
~ he exercise of this invention places no unusually
critical requirements on the nature or acid value of the
polyester resin to be used therein, other than the
requirement in respect of poly(ethylene oxide) content.
~owever, for the most stable processing conditions we
have found it preferable to work with resins which have
acid values of from 10-50 mgm ~OH per gm.
~ he choice of components available to the polyester
formulator is illustrated but not limited by the
following examples:
Unsaturated aliphatic acids, e.g. maleic, fumaric,
itaconic, citraconic and mesaconic acids.
Saturated aliphatic acids, e.g. malonic, succinic,
glutaric, adipic, pimelic, azaleic, hexa-
hydrophthalic and sebacic acids; and
~romatic acids, e.g. phthalic, iso-phthalic, tere-
phthalic, tetrachlorophthalic, trimellitic
and trimesic acids~
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1046197
~ he corresponding acid anhydrides, where they
exist, are also common components of such polyesters.
Suitable dihydric alcohols are chosen from, for
example, ethylene glycol, diethylene gl~col, hexane 1,
6-diol, propylene glycol, dicyclohexanol and neopentyl
glycol. Alternatively the alcohol may be one which
initiall~ contained three or more hydroxyl OEoups,
the groups in excess of two optionally being at least
in part etherified with, for example, a monohydric
alcohol e.g. methanol, ethanol and n-butanol, or
esterified with a monobasic acid, e.g. benzoic acid~
p tert-butyl benzoic acid and chain-like aliphatic acids
of up to 18 carbon atoms chain length e.g. coconut oil
fatty acid.
~he methods by which unsaturated polyesters of
this type are formulated and made are well known in the
art.
As disclosed hereinabove, the requirements of
this invention superimpose on the above-described
formulating practices the essential requirement that
the unsaturated polyester resin shall comprise 2-50%
by weight of poly(ethylene oxide) chains. For some
applications, the preferred range is 2-20% by weight.
~here are a number of ways in which a moiety of this
type may be incorporated into a polyester resin. ~he
terminal groups of poly(ethylene oxide) chains as
normally prepared are usually hydroxyl, although
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104ti~97
(depending on the pol~merisation method used) one group
can be an alkoxy, e.g. methoxy group. ~hus, with respect
to hydroxyl group concentration the poly(ethylene oxide)
may be mono- or di-functional, the difunctional species
commonly being referred to as poly(ethylene glycols).
~he nature of poly(ethylene oxides) is well known and
reviewed in~ for example, "Organic Polymer Chemistry"~
Saunders, E,J., Chapman and Hall, ~ondon, 1973. ~hus,
the most direct way of attaching a poly(ethylene oxide)
moiety to an unsaturated polyester is to utilise its
hydroxyl group or groups in an esterification reaction.
For example, a mono-hydroxy-terminated poly(ethylene
oxide) may be reacted through its hydroxyl group and a
carboxyl group of the polyester resin to lln;te both
- 15 ¢omponents through an ester linkage. On the other hand,
if the poly(ethylene oxide) chain is terminated at both
end~ by hydroxyl groups, it may be used as a dihydric
alcohol in the preparation of the unsaturated polyester
resin itself.
Poly(ethylene oxide) for use in this manner may
be readily prepared by known methods from ethylene
oxide and is also known commercially; for example,
certain proprietary products sold under the trade mark
- "Carbowaxr' (r~rade Mark of Union Carbide Corp , U.S.A,)
~or our purpose, the poly(ethylené oxide) must be
~ater-soluble at the granule processing temperature and
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1046197
have an average molecular weight of 1000 - 10,000~
Although the polymers must be essentially those of
ethylene oxide, we do not exclude by the use of this term
the presence therein of-a minor proportion of some other
alkylene oxide, for example propylene oxide, provided the
poly(alkylene oxide) as a whole remains water soluble
at the granule processing temperature.
An alternative indirect way of introducing poly
(ethylene oxide) into the polyester is to first react
a mono-hydroxyl-terminated poly(ethylene oxide) with
a tribasic acid, for example trimellitic acid anhydride, ~ -
in equimolar proportions, and then to use the dibasic
acid ester so-formed in the uL~aturated polyester resin
preparation as a diba~ic acid reactant.
~ he first step in preparing vesiculated granules
by our new process, is to dissolve the selected
unsaturated polye8ter resin in eth~lenically unsaturated
monomer with which it will co-react when polymerisation
is initiated by a free radicle mechanism. ~he
unsaturated monomer should be essentially water-insoluble
and we have found monomers with a solubility of le~s
than 5% by weight in water to be satisfactory for our
purpose.
A single monomer or a mixture of monomers may be
used and in general the monomer will contain only
a ~ingle polymerisable double bond. However, it is
known that poly-functional monomers, that is, monomers
containing more than one polymerisable double bond, are
.
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104~;197
also used to cross-link unsaturated polyester resins.
Such poly-functional monomers are, however, normally
present only as a minor constituent of a mixture of
monomers~ the major proportion of which is monofunctional
monomer. Hence, mixtures comprising e.g~ divinyl
benzene may be used in the performance of our invention.
~ he basis for selection of ethylenically unsaturated
monomer which will react with an unsaturated polymer is
well understood in the art and can be applied directly
to the process of the present invention. In practice,
we have found the most generally useful monomer to be
styrene, because of the ease with which it can be
polymerised with a broad range of unsaturate~ polyester
resins. However, excellent results are given by blends
of styrene with other monomer, notably Ivinyl toluene'
and methyl methacrylate. ~or the best results, we
prefer that the monomer shall oomprise at least 50% by
weight of styrene.
~ ~he choice of monomer is not, however, restricted
to the above monomers alone. ~earing in mind the
requirements that the total monomer must be essentially
insoluble in water and also be a solvent for the
unsaturated polyester resin, there may be present in a
minor proportion other polymerisable 11n~aturated monomers
to, for example, modify the physical properties of the
co-reacted resins. ~ypical co-monomers are, for example~
athyl acrylate, n-butyl methacrylate, acrylonitrile,
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- 1046197
and triallyl cyanurate. In general, we have found that
the upper limit of usefulness of such monomers is 10%
by weight based on the total monomer used. Higher
concentrations give granules which can be either too
5 brittle or too rubbery to be used effectively in~
for example~ paint compositions.
Optionally a few percent by weight of a non-polymerising
organic liquid, e.g. n-butanol or toluene, may be mixed
with the monomer to increase the solubility of the
pol~ester resin therei~ or may be introduced as an
incidental part of the process, e.g. in preparing the
polyester
When a solution of unsaturated polyester in
polymerisable monomer of this type is added to water with
vigorous stirring, it forms a self-stabilising suspension
of globules of polyester solution in the water. Stirring
is continued vigorou91y until the desired globule size,
which will correspond approximately to the final granule
size, is achieved. Reduction of the globules to size
may be hastened by the addition to the water of a limited
amount, not more than 5% by weight of the polyester, of
an anionic surfactant such as, for examp~e, "Aérosol" M.A.
(Aerosol is a- trade mark of the Americal Cyanimid Co.)~
or a water-æoluble colloid, for example hydroxy ethyl
2~ cellulose. At the same time, small discrete liquid
filled vesicles form spontaneously within the globules
of polyester resin solution. Each globule contains a
plurality of vesicles, the diameters of which are small
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1046197
relative to that of the globule diameter. Vesicle volumes
lie within the range of 20-60% of the globule volume.
When the globules haYe been reduced by stirring to
the desired granule diameter,a free radicle initiator is
added to the suspen~io~ to polymerise and hence cross-
link the polyester re~in granules. ~he initiator may be~
for example, an organic peroxide, e.g. benzoyl peroxide,
di-tert-butyl peroxide and methyl ethyl ketone peroxide,
in combination with an accelerator such as for example
diethyl aniline.
It has been proposed, for example in the
Australian patent specifications referred to hereinabove,
that the usefulness of vesiculated polymer granules is
enhanced by the inclusion in them of pigments, especially
opaque white pigments such as, for example, titanium
dioxide. Pigment may be incorporated in the granules
of this invention by pre-dispersing particles of the
chosen pigment in the unsaturated polyester resin
solution. In general, when the granule incorporates a
proportion of pigment, we have found it preferable to
adopt the option of adding up to 5% by weight of the
polyester of an anionic surfactant or a water-soluble
colloid, for example hydroxy ethyl cellulose, to the
water in which the suspension of globules of unsaturated
polyester resin solution is made,
Granules according to this process may be prepared
free of external added polymeric stabiliser which appears,
without preaudice to the nature of this invention, to
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1046197
be a contributing factor to the relative ease with which
they can then be separated from the water and dried.
~ he slurry of granules prepared as described
hereinabove may be concentrated by settling and then
'j deca~tating, the granules then being centrifuged or
filtered from the bulk of the remaining water. ~he
wet granules may then be dried by, for example, tray
drying in a hot air atmosphere or by using fluidized bed
techniques.
Granules of the type we now disclose, that is
granules of cross-linked polyester resin comprising
2-5~/o by weight of moieties of poly(ethylene oxide)
of average molecular weight 1000-10~000 are particularly
useful as components of paint films. A surprising and
15 valuable feature of these granules is that when they are
used at high concentrations by volume in the dry paint
fiim, that i5 when they comprise 60-90% by volume of
the film, the paints so-produced usually have improved
stain resistance to that of similar formulations made
20 from granules of the prior art referred to hereinabove.
~ he invention is illustrated by the following
examples in which all parts are given by weight:
E~AMPLE: 1
Preparation of a poly(e~hylene oxide) modified
25 unsaturated polyester resin.
A mixture of 29 parts of propylene glycol 27 parts
of fumaric acid 12 parts of phthalic anhydride and 7 parts
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~ 046197
of a poly(ethylene oxide) of molecular weight 6000 known
as "Carbowax"6000 (Trade Mark), were heated in a reaction
vessel fitted with a stirrer~ thermometer and condenser
and held under total reflux conditions for 2 hours.
3,5 part~ of xylerle wa~ then added to the flask and
a Dean and Stark trap fitted to collect water distilled
from the reaction. ~'he reaction mixture was kept
under reflux at temperature up to 210C and water was
removed until the acid value of the polyester fell to
30 mg ~OH/g resin. Heating was then stopped and the
reaction mixture cooled. 0.015 parts of hydroquinone
was added to the resin when the temperature had fallen
to 140C and 21 parts of styrene was added when the
temperature had fallen to 110C. The product was a
viscous amber coloured li~uid.
F~AMpIE 2
Preparation of pigmented vesiculated polyester
granules according to the invention.
14.16 parts of the polyester of Example 1 was
mixed with 5.80 parts of styrene, and 16.00 parts of
rutile titanium dioxide pigment was dispersed therein
by high speed mixing. 0.50 parts of a paste consisting
of 55% benzoyl peroxide in n-butyl benzyl phthalate
was added to the dispersion and thoroughly mixed.
~he above mixture was added with stirring to a
mixture of 62.40 parts of water and 0.29 parts of
~ydroxy ethyl cellulose. ~he actual grade used was
13 -
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10461g~
"~atrosol" 250 HR,("Natrosol"being a trade mark of
Hercules Co., U.S.A.). After stirring for one minute
f 0.46 parts of an 80% aqueous solution of sodium dihexyl
sulphosuccinate was added and stirring continued.
5 A stable oil-in-water emulsion of globules of polyester
resin solution in water was formed and stirring was
¢o~tinued until the maximum emulsion particle size
observed by microscopy was 30 micron. ~hen, 0.16 parts
of diethyl aniline was added and stirring stopped.
10 Over a period of 1 hour the temperature rose from 20C
to 40C indicating that an exothermic polymerization
reaction was occurring. ~he product was a slurry of
spherical pigmented vesiculated polymer granules~ the
vesicle volume of which was estimated by microscope
15 examination to be about 50% of the total OE anule volume.
EXAMPLE 3
Comparative example of a paint composition which
shows improved properties over a similar paint comprising
vesiculated polymer granules of the type disclosed in
20 Australian patent specification ~o.445,277.
Paint A
~o 4~.86 parts of the polymer granule slurry of
Example 2 was added 19.92 parts of an aqueous acrylic
latex (Rohm and Haas AC 61 was used) and 16.58 parts
25 of a 71% aqueous dispersion of rutile titanium dioxide
pigment. 1.4 parts of tributyl phosphate, 16.5 parts
of water and 0.18 parts of hydroxyethyl cellulose were
:
- 14 _
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added slowly and the mixture stirred until the viscosity
reached a constant value.
Paint B
A paint similar to paint A was made, with the
exception that the polymeric granules a~ u~ed in paint A
were substituted on a dry weight basis with vesiculated
polyester resin granules of the same size range but
prepared a¢cording to the teachings of Australian Patent
Specification 445,277.
Paint A and paint B were drawn down side b~ side
on a Morest hiding power chart to films of the same
thickness and allowed to dry in air overnight~ then
aged for a further 24 hours. Stains~ including a
dispersion of carbon black in mineral oil, black pencil,
15 red chalk and household dust, were then applied evenly to
both paint films.
~ he paints were scrubbed with a rag wet with water
and household detergent. It was observed that the stains
were removed more readily from paint A than from paint B.
20 In the case of the mineral oil stain, removal was almost
complete from film A but very slight only from film B
EXAMPIE 4
Preparation of pigment-free vesiculated polyester
resin granules by the process of this invention
~ 9 parts of polyester resin as prepared in
example 1 was added 30 parts of styrene and 3 parts of a
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1046197
55% by weight paste of benzoyl peroxide in n-butyl
benz~l phthalate, to form a clear solution. ~his
solution was then added with stirring to 200 parts of
water and formed therein a stable water-in-oil type
dispersion,
~ o the dispersion so-formed was added 0.8 parts
of diethylaniline, which initiated an exothermic
polymerisation reaction lasting about 2 hour~. The
product so-produced was an aqueous slurry of polyester
resin granules with a maximum diameter of about 50
micrometres, corresponding to the maximum diameter
of the unpolymerised initial water-in-oil type dispersion.
~he granules were found to contain about 50% by volume
of fine vesicles, which had formed therein spontaneously
during the granule manufacturing process.
Whe~ spread on trays and exposed to a current of
warm air~ the slurr~ dried to a soft white powder.
~ he preparation was repeated but with the addition
of 0.7 parts of hydroxyethyl cellulose to the water in
which ths initial oil-in-water type emulsion was made,
Approximatel~ the same degree of agitation was used in
preparing the dispersion, but in this case the final
maximum granule diameter was of the order of 20 micro-
metre, thus showing the usefulness of a water-soluble
colloid in aiding size reduction of ~ranules during this
process. ~he size and degree of vesiculation and the
facility with which these granules could be dried, closely
- 16
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1046197resembled those of the 50 micrometre granules.
EXAMPIæ 5
This example illustrates the preparation of
30 micrometre pigmented vesiculated polymeric polyester
resin granules according to the invention.
~ o 14.16 parts of the poly(ethylene oxide) modified
polyester of ~xample 1 was added 5.80 parts of styrene,
then 16.00 parts of rutile titanium dioxide pigment was
dispersed therein by high speed mixing. 0.50 parts
of a paste consis~ing of 55% by weight benzoyl
peroxide in n-butyl benzoyl phthalate was added to the
dispersion and thoroughly mixed.
~ he above mixture was added with stirring to a
m;Yture of 62.40 parts of water, 0.29 par~s of hydroxy
eth~l cullulose (as in example 2) and 0.52 parts of a
30% aqueous solution of a polyphosphate pigment
dispersant, After stirring for one minute, 0.46 parts
of an 80% aqueous solution of sodium dihexyl sulpho-
succinate was added and stirring continued. A stable
oil-in-water type dispersion was formed and stirring was
continued until the maximum disperse particle size observed
by microscopy was ~0 micrometres, after which 0.16 parts
of diethyl aniline was added an~ stirring stopped.
Over a period of 1 hour the temperature rose from 20C
25 to 40C indicating that an exothermic polymerisation -
- reaction was occurring. ~he product was a slurry of
spheroidal pigmented vesiculated polyester granules,
the vesicle volume of which was about 50% of the total
~ .
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16~4~197
granule volume. ~he aqueous slurr~ of granules was dried
after washing to give a soft powder of pigmented
vesiculated granules.
, EXAMPIE 6
Preparation 5 micrometre pigmented vesiculated polymeric
polyester resin granules according to the invention.
~o 27 parts of the poly(ethylene oxide) modified
polyester of example 1 was added 11 parts of styrene and
31 parts of a rutile titanium dioxide pigment was
dispersed therein. ~o this blend was then added 1 part
of a 55% by weight paste of benzoyl peroxide in n-butyl ,~
benzyl phthla's;e. ~he above dispersion was added with
stirring to a mixture of 118 parts of water, 1.8 parts
of hydroxyethylcellulose and 1.6 pàrts of sodium
dihexyl sulphosuocinate. An oil-in-water type
dispersion was formed, the particle ,size of which was ,'
reduced by vigorous mixing to an average value of about ,'~ ,'
5 micrometres. 16 part~ of water and 0.3 parts of '~`
diethylaniline were added and an exothermic reaction
was observed to take place over a period of about 2 hours.
~he product was a slurry of pigmented vesiculated polymer
' granules of an average size of about 5 micrometres.
~his was dried after washing to give a dry powder of
pigmented vesiculated polyester granules.
EXAMPI~ 7
Preparation according to the invention of pigmented
polyester resin granules with a low vesicle volume.
.~, .
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1046197
~ o 27 parts of the poly(ethylene oxide)modified
polyester of Example 1 was added 11 parts of styrene, then
31 parts of a rutile titanium dioxide pigment were
di~persed therein. Next, 1 part of a 55% by weight paste
of benzoyl peroxide in n-butyl benzyl phthalate wa~
added. ~his mixture was then added with ~tirring to an
a~ueou~ phase consisting of 120 parts of water, 0.5 parts
of hydroxyethyl cellulose, 3.5 parts of sodium chloride
and 0.5 parts of sodium dihexyl sulphosuccinate.
An oil-in-water type dispersion was formed, the disperse
particles of which were reduced by stirring to
approximately 30 micrometres maximum diameter. ~hen,
0.3 parts of diethylanili~e was then added to the
dispersion and an exothermic curing reaction was observed
to take place over a period of 2 hours. ~he product was
a slurry of pigmented polye~ter granules up to 30 micro-
metres in diameter and with a vesicle volume about 20%
of the total granule volume. ~he slurry dried in a
current of warm air to a soft white powder,
EXAMPIE 8
~his example illustrates the preparation of
vesiculated polyester resin granules according to the
invention.
A poly~thylene-oxide)modified polyester suitable
for the preparation of vesiculated polyester resin
granules according to the invention was prepared as
follows:
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1046197
33 parts of a methoxy poly(ethylene oxide) (containing
one terminal methoxy and a terminal hydroxyl group per
molecule) of average molecular weight 2100 was added to a
reaction vessel fitted with a stirrer, thermometer and
5 condenser together with 5 parts of xylene and ~.2 parts
of trimellitic anhydride. ~his mixture was held under
reflux at about 160C until the anhydride group
concentration by infra-red analysis had fallen to a
constant low value. ~he mixture was cooled to 1~0C
10 and 4 parts of phthalic anh~dride, 14 parts of fumaric
acid and 1~ parts of propylene glycol were added. ~he
mixture was heated to reflux and held for 1 hour~ A
Dean & Stark trap was then fitted to collect water condensed
from the reaction. ~he mixture was kept under reflux
15 at temperatures up to 210C and water was removed until
the acid value of the pol~ester fell to 30 mg EOH/g resin.
Heating was then stopped and the reaction mixture cooled.
0.015 parts of hydroquinone was added when the
temperature had fallen to 140C and 26 parts of styrene
20 was added when the temperature had fallen to 110C.
The product was a viscous turbid amber coloured liquid.
~ he polyester resin so-produced was then used to
prepare vesiculated granules by the methods described in
examples 4-7. Granules of similar properties were
25 obtained from the polyester of this example to those
obtained from the polyester of example 1.
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1046197
EXAMP~E 9
- ~his example illustrates the preparation of
vesiculated polyester resin granules according to the
invention using various poly(ethylene oxide) modified
polyester resins as described hereunder:
(a) A poly(ethylene oxide) modified polyester
was prepared by the method of example 1,
but with the substitution of one half of
the propylene glycol with neopentyl glycol
on an equimolar hasis.
(-bj A poly(ethylene oxide) modified polyester
resin was prepared by the method of example 1
but with the substitution of the fumaric
acid with maleic anhydride on a equimolar
basis.
(c) A poly(ethylene oxide) modified polye~ter
resin was prepared by the method of example 1,
but with the substitution of 10 percent by
weight of the styrene monomer with methyl
methacrylate monomer.
(d) A poly(ethylene oxide) modified polyester
resin was prepared by the method of example 1,
but with the substitution of 10 percent by
weight of the styrene monomer with vinyl
toluene monomer.
~ he above polyesters were converted in turn into
vesiculated polymer granules by the method of example 2
and found to give satisfactory vesiculated polyester
re~in granules.
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EXAMPIE 10
Thi~ example illustrates by way of comparison
processes for preparing vesiculated polyester resin
granules outside the scope of the present invention.
Ve~iculated polyester granules were attempted to
be prepared, wherein the polyester resins were as follows.
(a) A polyester resin was prepared by the
method of example 1 but using 70 parts of a
6000 molecular weight poly(ethylene oxide) ~ -
in place of 7 parts thereof.
~he product when cooled was a semi solid and could
not be converted into vesiculated pol~mer granules by the
method of the invention.-
(b) A polyester resin was prepared by the
method of example 1 but using 1 part of poly
(ethylene oxide) molecular weight 6000 in
place of 7 parts thereof,
~he product was a viscous amber liquid which did not
produce a stable dispersion in water by the method of
example 2 and could not be cured to give a dispersion of
vesiculated polyester resin granules according to the
invention.
(c) A polyester resin was prepared by the method
of example 1 but using an equal weight of a
poly(ethylene oxide) of average molecular
weight 600 in place of the poly(eth~lene oxide)
of average molecular weight 6000.
- 22 -
.
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146197
~he product waq a viscous amber liquid which did
not form a stable dispersion in water by the method of ~ ~-
Example 2 and could not be cured to ~ive a dispersion of
ve~iculated polyester resin granules according to the
invention.
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- 23 -
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