Note: Descriptions are shown in the official language in which they were submitted.
ll~SS639
This invention relates to free-flowing moulding
compositions which harden with very little shrinkage,
based on unsaturated polyesters, polymerisable monomers
and graft-polymerised elastomers.
Conventional unsaturated polyester resins undergo
considerable shrinkage during polymerisation which is
a serious disadvantage in the production of shaped
articles having a satisfactory surface finish. It is
known from numerous publications (German Published Speci-
fication Nos. 1,694,857; 1,803,345; 1,953,062; 2,051,663;
2,061,585, French Patent No. 1,148,285~ that polyester mouId-
ing compositions, with which certain thermoplasts have been
mixed before hardening, can be hardened with very little
shrinkage.
The above applications relate both to liquid casting
resins and also to resins which have been thickened by the
addition of fillers or thickeners and which, on account of
their tackiness, are naturally unsuitable for the production
of ~ree-flowing polyester moulding compositions in the
absence of other aids. These tacky resins can only be
processed into free-flowing compositions by adding
such large ~uantities of fillers that the resulting poly-
ester compositions can no longer be processed in in-
~ jection moulding machines, in addition to which their
;~ mechanical properties generally no longer comply with
f practical requirements.
According to German Published Specification No. 2 234 307
polyester moulding compositions which harden with very
little shrinkage can be obtained in free-flowing form
::
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l(~S563~
when they have the following composition:
a) 30 t~ 70 ~0 by weight of an unsaturated crystalline
polyester containing fumaric acid radicals and
. radicals of glycols correspo;nding to the general
. .
. 5 formula H0-CH2-R CH2-OH, whlere R represents an
alkylene of the for~ula (CH2)z (z = 1 - 18) or
symmetrical dialkyl derivatives of these alkylene
.;~ radicals, the alkyl substituents being situated
on the same carbon atom, or cycloalkylene radicals,
b) 20 to 75 ~ by weight o~ styrene, and
c) 1 to 30 ~ by weight of cellulose esters o~ organic
acids, such as ~or example cellulose acetates,
~; cellulose acetopropionates or cellulose ac~to-
butyrates.
In order to minimise shrinkage of the polyester
moulding compositions, 1t is generally necessary to
; add from 10 to 20 % by weight of a thermoplast
Obviously the danger of adding thermoplastic poly-
; ~ers to crystalline unsaturated polyester resins in
quantities as large as these, at leas-t in the case
of some thermoplasts c), is that crystallisation
speed is reduced and tacky resins are obtained which
are unsuitable for the production of free-flowing
polyester moulding compositions in the sense o~ the
present application. However, -these difficulties
can be overcome by selecting special thermoplasts.
One skilled in the art would expect that the
favourable mechanical properties which pure unsaturated
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~055639
polyester resins are known to ha~e are considerably
influenced by the addition of thermoplasts. Sinee, in
addition, the shrinkage has a direct linear dependence
upon the ther~.oplast content in c~nventional non-free-
flowing, low-shrinkage polyester moulding compositions,
- ~atisfactory surface finishes and unchanged mechanical
properties have hitherto ~ppeared to cancel each other
out. An ideal combination was apparently not within
the realms of possibility.
It has now surprisingly been found that the
disadvantages referred to above can be obviated by new
polyester resin mixtures eontainlng graft-p~lymerised
elastomers ~9 their shrinkage-reducing eomp~nent.
Aeeor~ingly, the present invention relates to low-
; 15 shrinkage moulding eompositions based on unsaturated
polyesters whieh are free-flowing even in the absenee
of fillers or ehemieal thickeners, eontaining
A, 20 to 80 ~ by weight and preferably 30 to 50 ~
by weight, based on the sum of components A - C of a
cry~talline polyester based on ~ ~-unsatura-ted diearboxy~e
acid radicals,containing fu~aric aeid radicals and
radicals o~ glycols corresponding to the general ~ormula
H0-CH2-R-CH2-OH, in which R represen-ts an alkylene of
,- the for~ula ~CH2)x (x = O to 18), symmetrical dialkyl
. 25 derivatives o~ these alkylen~ radieals, the alkyl sub-
stituen-ts being situated on the same carbon atom, or
cycloalkylene radicals,
Lo A 15 499 ~ 3 ~
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. B. 18 to 70 % by weight, preferably 30 to 60 % by weight, based on the sum of components A - C
of polymerisable vinyl monomers,
C. 2 to 50 % by weight, preferably 3 to 15 % by ~ :
weight, based on the sum of components A - C of
; a graft-polymerised elastomer, the precentages of
A ~ B ~ C amounting to 100. ~ :
In the context of the invention, unsaturated . :
`. polyesters are polycondensation produc~s of fumaric
10 and/or maleic acid or their ester-orming derivatives
containing a~ least 70 mol-% of fumaric acid radicals
based on the acid components, with the above-mentioned ~ :
glycols, such as ethylene glycol, 1,3-propane diol, 1,4-
butane diol, l,S-pantane diol, 1,6-hexane diol, 1,10- ~.
decane diol, 1,18-octadecane diol, neopentyl glycol,
: 3,3-dimethyl-1,5-pentane diol and 1,4-hydroxy methyl
cyclohexane. Particularly preferred diols are ethylene
glycol, 1,3-propane diol, 1,4-butane diol and neopentyl
glycol.
It is expressly pointed out at this juncture that
maleic acid radicals inhibit the crystallisation of ,:
polyesters containing fumaric acid radicals to a far
lesser extent than had been assumed, A maleic acid
content of 30 mol % is not in the least troublesome.
If desired, up to 20 mol % of the sym~tetrical
diols may be replaced by an equivalent quantity of :~ .
monohydric or polyhydric alcohols or asymmetrical
diols, and up to 20 mol % of unsaturated dicarboxylic
: ,. .: , .
.'' ,' ' '
: . '
1~55639
acids or their ester-forming derivatives by an equivalent
quantity of monocarboxylic acids or saturated dicarboxylic
acids or their ester-forming derivatives (cf. J.
Bjorksten et al., "Polyesters and their Applicationl',
Reinhold Publishing Corp., New York, 1956)o Examples
of those alcohols include monohydric ~lcohols
having 1 to 6 carbon atoms, such as methanol, ethanol,
propanol, butanol, cyclohexanol; glycerol, also trim-
ethylol propane, pentaerythritol, allyl alcohol, dieth-
ylene glycol, triethylene glycol and partial etherif-
ication products of the aforementioned polyhydric alcohols,
such as allyl, methallyl, ethallyl, chlorallyl and
crotyl ether~. Examples of tho~e acid components ;~¦are o-phthalic aoid, isophthalic acid, terephthalic
acid, hexahydrophth~lio acid, tetrachlorophthalic acid,
endomethylene tetrahydrophthalic acid, hexachloro-
endomethylene tetrahydrophthalic acid, succinic acid,
glutaric acid, adipic acid, pimelic acid, benzoic acid,
acrylic acid and methacrylic acid or the ester-forming
derivatives of these acids.
The incorporation of these esterification components
lowers the melting point of the crystalline, unsaturated
polyester, which can be advantageous to a certain
extent, especially in the case of crystalline polyesters
which normally have a very high melting point, because
a very high melting point complicates the incorporation
of fillers and other additives.
The dicarboxylic acid or its derivatives and the
glycols are reacted at elevated temperature, preferably
at temperatures in the range from 150 to 210C, until
a product having an acid number below 100 is obtained.
The acid numbers of the unsaturated polyesters s]hould
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be from 10 to 100, preferably from 20 to 70, whilst their
- hydroxyl nu~bers should be from 10 to 150, pre~erably
~rom 20 to 100. The molecular weights of the polyesters
may fluctuate within a wide range, although they are
normally in the range from 500 to 5000 and pre~erably
in the range ~rom 1000 to 3000 (measured by vapor-
pressure osmosis in dioxane and acetone).
Polymerisable vinyl mon~mers suitable for the
purposes of the invention include the unsaturated
compounds normally encountered in polyester technology
which preferably contain a-substituted vinyl groups or
~-substituted allyl groups such as, for example,
nucleu~-chlorinated and -al}cy~ated styrenes, the
alkyl groups contAining from 1 to ll carbon atoms such
~s for ex~mple styr~ne, vinyl toluene, divinyl ben~en~,
~-meth~l styrene, tert.-butyl styrene, chlorostyrenes,
vinyl acetate, optionally in admixture with small
quantities of acrylic acid and methacrylic acid and/or
their esters having 1 to 4 carbon atoms in the alcohol
component, acrylonitrile and methacrylonitrile, allyl
esters such as allyl acetate, allyl(meth)acrylate,
phthalia aoid diallyl ester, triallyl phosphate and
triallyl cyanurate.
Graft-polymerised elastomers suitable for the
purposes of the invention are those which can be
produced by polymerisation of b) in the presence of a~,
a) denoting 10 to 90 % by weight, preferably 45 to 90 % by
weight, based on component C of a rubber-elastic butadiene
polymer with up to 50 % by weight, based on a) of copoly-
merised styrene, acrylonitrile, methacrylonitrile and/or
acrylic methacrylic acid esters ha~ing 1 to 18 carbon
atoms in the alcohol component, and
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1~55639
b) denoting ~rom 90 to 10 % by weight, preferably from 55 to
10 % by weight based on component C of styrene or with
styrene copolymerisable monomers such as, ~or example,
acrylonitrile, methacrylonitrile, esters of acrylic acid and
methacrylic acid having 1 to 18 carbon atoms in the alcohol
chain, styrenes substituted by halogen atoms or aliphatic
radicals having 1 to 6 carbon atoms, such as ~-methyl styrene,
tert.-butyl styrene, vinyl toluene, divinyl benzene, chloro-
styrenes or mixtures thereof. The percentages of a) + b)
amount to 100.
Instead of using the optionally modified rubber-elastic
butadiene polymers a), it is also possible to use isoprene
polymers, rubber-elastic polyacrylic acid esters, EPDM-
rubbers and polypen~tenamer/polyhexenamer rubbers.
The gra~t-polymerised elastomers are produced in known
.~anner either in solution or in emulsion. They can show any
particular stereospecl~icity and, in the case of copolymers,
any particular distribution of the monomer components in the
, polymer chain. The rubber-elastic butadiene polymers usually
j 20 have a glass temperature~according to K. H. Illers and H.
Breuer, Kolloid-Zeitschrift ~ , 110 (1961)] of below 0 C,
preferably below -30 C.
The mixtures according to the invention contain
conv~ntional polymerisation inhibitors, which prevent
premature, uncontrolled gelation, in the usual quantities,
preferably in quantities of from O.OOl to O.l % by weight.
Suitable polymerisation inhibitors include phenols and
phenol derivatives, preferably sterically hindered
phenols whlch contain alkyl substituents having l to 6
carbon atoms in both o-positions to the phenolic
hydroxy group, amines~ preferably secondary aryl amines
and their derivatives, quinones, copper s~lts of
organic acids, addition compounds of Cu(I)-halides
Le A 15 4gg _ 7 _
~OSS639
with phosphites9 such as for example 4,4'-bis-(2,6-
di-tert.-butyl phenol), 1,3,5-trimethyl-2,4,6-tris-
(3,5-di-tert.-butyl-4-hydroxy benzyl)-benzene, 4,4~-
butylidene-bis-(6-tert.-butyl-m-cresol)9 3,5-di-tert.-
butyl-4-hydroxy benzyl phosphonic acid diethyl ester,
N,N'-bis-(~-naphthyl)-p-phenylene diamine, N,N~-bis-
(l-methyl heptyl)-p-phenylene diamine, phenyl-~-
naphthyl ~aine, 4,4'-bis-~,a-dimethyl benzyl)-diphenyl
amine, 1,3,5-tris-(3,5-di-tert.-butyl-~-hydroxy
hydrocinnamoyl)-hexahydro-s-triazine, hydroquinone,
p-benzoquinone, toluhydroquinone, ~-tert.-butyl
pyrocatechlol, chloranil, naphtho~uinone, copper
n~phthenate, copper octoate, Cu(I)Cl/triphenyl phosphite,
Cu(I)Cl/trimethyl phosphite, Cu(I)Cl/trischloroethyl
phosphite, Cu(I)Cl/tripropyl phosphite and p-nitroso-
dimethyl aniline.
The polyester moulding compositions according to the
invention contain the usual quantities, preferably
from 0.1 to 5 ~ by weight, of polymerisation initiators
such as, for example, diacyl peroxides such as diacetyl
peroxide, dibenzoyl peroxide, di-~-chloroben~oyl
peroxide, peroxy esters such as tert.-butyl peroxy
acetate, tert.-butyl peroxy benzoate, dicyclohexyl
peroxy dicarbonate, alkyl peroxides such as bis-(tert.-
butyl peroxy butane), dicumyl peroxide, tert,-butyl
cumyl peroxide, hydroperoxides such as cumene hydro- -
peroxide, tert.-butyl hydroperoxide, cyclohexanone
hydroperoxide, methyl ethyl ketone hydroperoxide, ketone
peroxides such as acetyl acetone peroxide, or a~oiso-
butyrodinitrile~
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1~)55639
Chemical thickeners may be added in quantities of
froln 0.1 to 10 % by weight and preferably in quantities
of from 0.5 to 5.0 ~ by weight, based on the sum total
of` components A to C. In the conte~t of the invention,
chemical thickeners are the oxide~ and hydroxi~es of
the metals of the Second ~ain Group of the Periodic
System, especially magnesium and calcium, to which
sm~ll quantities o~ water may optionally be added.
In addtion, up to 300 ~ by weight and preferably
from 50 to 200 % by weight, based on A to C o~ fillers may
be added to the polyester compositions according to the
invention. Suitable fillers are inorganic materials,such as
; c~lcium carbonate, silicates, aluminas, lim~, oarbon,
asbestos, ~lass, metnls, especi~l]y in the form of
fibres, woven ~abrics or mat~ and organic fillers
such as cotton, sisal, jute, polyester, polyamide,
; again in the form of libres of woven fabrics.
In addition, inorganic or organic pigments, dyes,
lubricants and release agents such as zinc stearate,
UV-absorbers, etc., may of course a~so be added in the
usual quantities if desired.
Thc composition according to the invention is prefer-
ably homogenised at a temperature at which the unsatur-
ated polyester exists in molten form, i.e. at temperatures
in the range fro~ 70 to 120C, so that the solutions o~
the molten crystalline polyester in pol~nerisable
vinyl monomers or the molten polyesters themselves are
mixed with the graft~polymerised elastomers which may
optionally be present in admixture with polymerisable
vinyl monomers. All other fillers and additives may be
added together with the individual ColDpOnentS Cooling
of the mass to room temperature gives a readily
~2 - 9 _
` 105563g
grindable, non-agglomerating ~ree-flowing moulding
composition which can be heat-hardened in heated moulds
to form low-shrinkage mouldings. A free-flowing
granulate can also be produced for example by impreg-
nating a glass fibre strand with th~e unstrengthened
mixture under heat and after cooling to room temperature
chopping the strand into a granulate.
In cases where the polymerisation initiator is
added as described to -the molten mixture according to
the invention, care must be taken to ensure that its
decomposition temperature is distinctly (approx. 20C)
above the melting temperature ol the crystalline polyester.
If the polymerisation initiator is present in solid,
free-flowing form, it may also be added to the free-
flowing mixture atroom temperature, provided that the
free-flowing mixture is suitably fine-grained.
The moulding temperature is preferably in the
range from 120 to 180C, and most preferably about
140C. The moulding time is generally from 2 to 10
minutes, preferably about 4 minutes, for a moulding
pressure of from 10 to 100 kp/cm2.
The mix-ture according to the invention, for
example with a vinyl monomer content of 40 %, are
compositions which are solid and free-flowing at room
temperature, even in the absence of fillers, which is
all the more surprising insofar as the ability of the
crystallisable unsaturated polyesters to crystallise
out in molten form from aromatic vinyl compounds to
form a solid mass with inclusion of aromatic vinyl
compounds is lost by the addition of conventional
thermoplasts, for example polystyrene, polymethyl
methacrylate or cellulose acetobutyrate, or takes
Le A 1~ 499 - 10 -
~055639
too much time.
Considerably lar6er quantities of vinyl monomers
may be added to the mixtures according to the invention,
especially where graft polymers with a high rubber content
are used, than to the crystalline polyesters without any
addition of graft polymers, without any loss of fluidity.
The compositions change into a paste-like form which is
of particular advantage because the shrinkage of the
- mouldings can be further reduced by increasing the vinyl
monomer content of the moulding compositions.
It has also been found that the shrinkage which
the mouldings undergo is a minimum with a graft polymer
content of from 5 to 10 % by weight, based on the three-
component system without any other additives. The
degree of shrinkage increnses again both with smaller
and with larger quantities of graft polymer. This is
all the more surprising since the shrinkage effect has
a direct linear dependence upon the thermoplast content
in conventional, non-free-flowing low-shrinkage moulding
compositions, in which an addition of from 10 to 20 ~
by weight of thermoplast is required to obtain minimal
shrinkage. In view of the small quantity of graft
polymer required, the polyester moulding composltions
according to the invention retain the well-known,
valuable properties of thermoplast-free polyester moulding
compositions.
It has also been found that the freedom from
shrinkage of hardened mouldings is dependent -to a very
large extent upon the styrene compatibility of the
polyester used, styrene-incompatible polyester~; Kiving
moulding compositions with the least shrinkage, whilst
styrene-compatible polyesters give moulding compositions
Le A_15 499 - 11 -
~OS56;~
with greater shrinkage.
The styrene compatibility or even styrene solubility
of unsaturated polyesters is a l~el:L-known concept in the
chemistry and technology o~ unsnturated polyester
resins: cf. Johannes Scheiber, "Chemie und Technologie
der kunstlichen Har~e", vol. I, "Die Polymerisathar~e",
Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart,
1961, 2nd. Edition, pages 563 et seq, more especially
pages 566 and 571/572.
The styrene compatibility of unsaturated polyesters
expressed in % by weight of unsaturated polyester, based
on the total quantity of unsaturated polyester and
styrene, is defined nnd determined as follows:
Unsnturated polyeqter is dissolved in ætyrene at
110C in exactly the quantity required to obtain a clear
qolution of known concentration. More styrene is then
added with stirring to the resulting solution until it
clouds. The concentration, based on the total quantity
of styrene and unsaturated polyester, of the unsaturated
polyester in % by weight at the clouding point is
defined as styrene compatibility.
The clouding point can be made easier to deterrnine
by using a black background during dilution with styrene.
The styrene used preferably contains an inhibitor, for
example 0.2 ~ by weight of tertl-butyl pyrocatechol
in order to prevent hazing by foreign substances, for
example polystyrene, which would only complicate the
determination.
The following exal~ple serYes as an illustration:
E (g) = quantity weighed in ~in grams), for example
20 g of the clear polyester solution in styrene,
the solution having a concentration of P %
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o~ unsaturated polyester
P (%) = the concentration ~in ~p by weight), o~
unsaturated polyester dissolved -to form a
clear solution in styrene, for example 60 %
S (g) = quantity o~ styrene in grams a~ded to obtain
the clouding point, for example 10 g
Styrene compatibility = E (g) . P (~)
E (g) ~ S ~g)
for example 20 g . 60 %
20 g ~ 10 g
By definition, there~ore, styrene compatibil:ity is
greater the lower the percentage.
Experience has shown that the styrene compatlbility
of ~n unsaturated polyester ix influenced by the
polyester components involved in its synthesis, i.e. by
the acids and hydroxy co~pounds used in -the syn-thesis
of the polyester.
Esterification components which cause styrene in-
compatibility are, for example, maleic acid and i-ts
~0 anhydride, fumaric acid and ethylene glycol.
Esterification components which cause styrene
compatibility are, for e~ample, phthalic aoi~, isophthalic
acid, tetrachlorophthalic acid, hexachloro-endomethylene
tetrahydrophthalic acid or their anhydrides, 1,2-
propane diol, 1,3-butane diol, neopentyl glycol and
trimethylol propane allyl ether.
As already mentioned, the more styrene-incompatible
the unsaturated polyester and the greater the quantity
of styrene present in the mixture produces a lower
shrinkage of hardened mouldings. Styrane-incompatible
polyesters containing more styrene than corresponds to
their styrene compatibility "repel" the styrene and give
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1055639
wet mouldin~ com~o.~itions from which it is only p~ssible
to nbtain unusa~le, bu~ble-contain:ing and heavily
distorte~ moul(lings. These faults, together with
the loss Or fluidity, c~n be avoided by adding the
graft-p~lymerised elastomers accorcling to the invention.
El~stomers with a high rubber content are most capable
of ~inding the styrene repelled by the polyester. As
cnn be seen from the Examples, mouldings based on these
combinations are those wi-th the lowest shrinkage.
The properties of thc hardened polyester mouldings
are influenced not only by the styrene compatibility
of the polyester ~nd the ty~e and quantity of thermo-
plast added ~ut also ~y processing which also determincs
the degree of shrlnkage; cf. Sch~ -Wal~ and 0. Walter,
Kunststorf-Rundsohau, 1972, No. 11, page 592:
1. Mouldings in which the glass fibres are arranged
in the moulding direction shrink to a far lesser extent
than mouldings in which the glass fibres are arranged
transversely of the moulding direction.
2. Shrinka~e increases with increasing moulding pressure.
3. Surface gloss and smoothness increase with increasing
mould tempera-ture. However, i-r n certaLn temperature is
exceeded, ~ull patches appear.
4. Surface gloss can be considerably increased by
ex$ending the moulding time,
5, The tendency towards speck formation is reduced to
an e~tent which is greater, the more slowly the catalyst
system reacts, i.e. the higher the initiation temperature
of the catalyst.
To sum up, lt can be said that the reaction-induced
shrinkage of a low-shrinkage polyester resin is governed
by pressure. This means not only that the degree of
Le A 15 499 - 14 -
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shrinlsage differs according to the ~noulding pressure,
bllt also thnt it varies ~ithin the mou~ding itself
depending upon position, direction, glass fibre
orientation or material thickness.
_Yampl~s and Comparison Tests
Percentages are percent by weight.
Production ~ the unsaturated polyesters (UP)
The unsatura-ted polyesters are obtained in known
manner by melt condensation. They are stabilised with
0.02 ~ of hydroquinone, based on the unsaturated
- polyester. The composition of the polyesters, and their
characteristics, are set out in the following Table.
~P 1 UP 2UP ', UP
F~ arl( acid g 1160 11601160
Malcic ac~(t anhydride g - - - 980
i Ethylenc glycol g 682 - - -
1,3-propane diol g - 798 - -
1,4-butane diol g - - - 945
Neopentyl glycol g - - 1071
Characteristics
Acid number [mg KOH/g] 48 38 35 l~2
Styrene compatibility 71~ 38~ '2~ ~ 2%
Cr~stallisation behaviour in solution in s~yrelle
Clouding temperature (C) 63 98 85 93
Solidification temperature 57 90 83 74
fumarate (according to
N~-spectrum3 100 100 100 73
~ .... ...
Styrene compatibility was determined in test tubes
in the same way as described above.
Crystallisation behaviour was determined as follows:
2 g of styrene containing 002 % by weight of ~-tert.-
.,
1~55639
b~tyl T)yrocatechol were diss~lved at ahout 120C in 8 g
o-f molten, unsaturated polyes-ter in a test tube (~iameter
l& mm, Icngth 1~0 mm), nnd th~ solution left to cool to
room temper~turc wl~ile s-tirring with a thermomcter.
The ~emperature at which th~ solution hccame c10udy
throu~h the lorma-tion of the first few crystal seeds
is called the clouding temperature, whilst thc temperature
at whic}l the solution solidified is called the solid-
iricntion temperatllre.,
graft~})olymerised elastomer E ], prcpared from
8() ~ of ~L polybutadiene rubber graft-polymerised in
a~lueous-emulsion with 18 ~ of styrene nnd 2 ~0 of acry-
lonitrilo, was used ror thc ~ollowing tests,
The polyl)uta~lcne rubber used was a coarse-pArtiole
te~ hnvlng arl avcrllge particle si~e ol from 0.25 to
o.65 ,u, the grafting base, tested in the form of solid
rubber, having n gel content of 80 ~ by weight and a
Mooney viscosity of ~0 ML-~, as measured in accordance
with DIN 53 52~. The polybutadiene rnbber was prepared
2() by emulsion polymerisation at ~5 to 80C.
Production of the 3-oomPonent systems
Group 1: Variation of the polye.sters
To prcpare the 3-component systems according to
the invention, batches of 5 g of the graft-polymerised
elastomer E 1 were impregnated with 40 g of styrene,
containing 0.02 ~ by weight of benzoquinone in dissolved
form, the resulting mass was heated to 80C and batches
of 55 g of the molten, unsaturated polyesters UP 1 to
UP 4, ~eated to 110C, were allo-Yed to flow in with
stirring. Cooling of the mixtures at the temperatures
indicated produced solid, free-flolYing compositions which
are designrLted UP l/E 1 to UP 4/E 1 and ~YhiCh represent the
Le A 15 ~99 - 16 -
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n~ c; O r Gro~
~i r oul) 1:
k~ nl) 1 e: UP l/E 1 IJI' 2/~ 1 Ul' 3/E 1 U~ 4/E 1
Sol-i(lil`icntiorl
telllpe:r~tnre: 61 ~ 7~ 73
ComF)orlent sy.stems, in which the qu.lnt:ity of gra~`t-
ol~merisc(l elastomer E 1 w~s rcp:klced by the unsatur~te(l
l)olyc~;ter for comp~?ris~ i th the 3-component ~ystemg
nccor(~itlg to the invention, l~erc llsed rOr com~)rlri son
tests. Tl~ese co-nparison compositions arc designatod
UP l/V to UP ~I/V nnd, herlce, COtlSiSt of 40 % of' styrene
nnd GO $ of unsaturated po].yester.
ro!~ 2': V riat.ion o~ th_ e ~rart-pol~neri.sefl elastolners
.~n tho ;I'ol.lo~in~r l~,~nm~los, thc systcm UP 3/E 1. ~a~
mo(lif.io~ t;o thc extent that elastomors E 2 and E 3, ~ith
the follo~in~ composi-tiotls, ~ere used instea~ of the
~ra-ft-polytnerise(l elastomer E 1:
E 2 E 3
Po lybllta(lietle rubber content: 50 ~
Styrene content: 3G ~ 63 ~O
Acrylonitr.ile cl)ntcnt~ 25
Tho compo~it:ion ol the satnples con-tflinin~ these
elastolllers and their solidification temperatures are shown
in the fol.lowin~ Table:
,, .
~ .Yamples UP 3/E 1 UP 3/E 2 UP 3/E 3
. __ . ~_ ~ __
UP 3 contcnt: 55 ~O 55 % 55 %
Styrene content: 40 ~p 40 ~O 40
E 1 content: 5 %
E 2 content _ 5 O
E 3 content: - - 5 %
. .
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1~551639
Solillifio~ltioll lol1l~)eruture 7'(' ()()~'~ G7(,
Grollp 3: Vnriat ion o~ tlle (~allt,i l;~ ol ~;r.l:l'l, poly!nf~r 1~: 1
In t~l~f? I'ollOWi 11~ inmples, 1~ Ig ol the XamI)lf~?
III' I/E ] l~S Ino(lifi((l to tlIc~ ex~eIIl tlIat polyest~?r IJP 1
r~ Iy r~ ?(l ~v ~r(lft I)olyllIer E 1.
Com~)osit~iolI of Groll~
?IJl' 1/~ JP l/U I Ul' l~ P l/E 13
,
III' 1 oontont:57 ,0 55 tfff 50 50 ~ 5 /'o
E 1 C 011 t f~?rl t: 3 ,~ 5 ,c 1(),~, 15 ,'
1(
Styrell(? COIltent:40 ~ 1lO ,f /10 ~j~ /10
Group ~: Variatiotl ol the styren~ conten-t
In the ~ollowing Examp1es, mi~ing of the salIlple
ur l/E 1 was moclit`ied to -the extent -that polyester UP 1
~as increnslngly replaced ~y styrene.
Conl~ositlon o~ Group l~
E~alnple UP 11/~ 1UP 12/~ 1UP 1/~ 1UP 13/E 1
UP 1 content: 80 ~D65 ~ 55 ~ 45 %
E I content: 5 ~ 5 ~ 5 ~ 5 ~
Styrene content: 15 ,'0 30 ,~ 40 ,~0 50 %
Production of harden~ble, free-flowin~ pol~ester mouldin~
compositions
To assess the 3-component rnixtures according to the
invention, the compositions ~ere m~]te(l at approximately
2~ 80C in a heated kneader and homogeneously kneaded with
the a~ditives indicated below. Finally, the peroxide
was added and the mi~ture subsequently cooled to room
temperature, resulting in the formation of free-flowing
llardenable compositions.
100.00 parts by weight of mixture according to the
invention and comparison mixture
100.00 parts by weight of calcium carbonate
1,50 parts by weight of magnesium oxide
4.00 parts by weight of ~.inc stearate
Le ~ 15 499 - 18 -
,. " ,; ,. . . .
~L~55~i3g
5 parts ~)y weig~lt of iron oxide l)lack
.35 par~s by wei~ht ol` iron oxide red
.75 parts by weight Or tert.-butyl perben~oate
In the ca~e oi t~le sampl~s corltairling the l)olyester
U~' ', I;he mixture was mixed ~ith the additives at ll~C
and~ ins-tea(l of the tert.-butyl perhen~oate, dicumyl per-
oxide powder was added to the cooled, -ri~e~ rticle
~nass at room temperature.
Reinforcing f`ibres were deliberately not added hecause,
1() as already mentioned, they promote irregular shrinkage in
view of` the diYferent orientation of the fibres.
Arter ~tornge ror 1 day at room temperature, the poly-
ester moulding composition were moul~led in a ~leat~d lab-
oratory press to form oylindrtcal mouldirlgs oach weighing
1~ g for a height of approxima~tely ~5 mm.
The mould used was in the ~orm of an oil-heated and oil-
cooled cylinder with an internal diameter o~ 20 mm which
was closed by a piston ~t its upper and lower ends (Bosch-
diesel-injection pump). The material was introduced at
~0 30C. The upper piston was loaded through a lever arm
with a pressure of 25 and 50 kp/cm~ and the moulcl heated
to 140C. The displacement of the upper pistorl was recorded
as a i`unc-tion of time by means of an inductive displacement
pick-up (cf. upper part of the graph). A point containing
a thermocouple projected into the moulding from the lower
piston. The temperature pattern obtained in the moulding
as a functionof time is shown in the lower part of the
graph. After the exothermic reaction had adated i.e. after
7 minutes, the mould was cooled to 30C~
The symbols used in the graph have the following
meanings:
a) Composition introduced, mould closed, composition
Le A 1~ 499 - 19 -
1~55639
~lei~t~ nd expclnds
I)) Co~position ~lcls almost reaclled the tnouldill~ temper-
~Itllre re.lCtiOn begillS, COlllpt)Si tiOII Sllrink.4 thrOUg}l
polymeri~sation-induced shrink~ge
c) Temperature max:imuln, reacti(>n and polymerisation
shrillk.ige lar~ely over, mass ~ools to the temperature
of the mould and shows limite(~ heat shrinkage
~) ~loul~l is cooled, mouldillg shows heat shrinkage
e) l~oom temperatllre re~chetl
I() i~ denotes the polymerisation-induced shrinlcage,
n is the maximum linear expansion,
C is the heat-induced s~lrinl~age.
A and ~ wer(? associnted ~y the follow:in~, rol~ltion:
llellltive shrinkage S (rel) = A . 10()/~1,
The valuc (, was su~stantially the samc in all tests and
was ignored. Since in a].l æamples the quantity and type
of additives were kept constant, S (rel) prov:ides a clear
indication of the shrinkage properties of the mixtures
according to the invention.
2() The rel~tive shrinkage v~lues :~ound in the moulding
compositions UP l/E 1 to UP 4/E 1 accord.ing t~ the invention
~nd in the correspon~ing comparison samples UP l/V to UP l~/V
are sho~n in groups in the following Tablc:
S (rel) of Group 1 (Variation of the pol~esters~ :
S (rel) 2 2
under 25 kp/cmunder 50 kp/cm
Samples moulding pressure ~oulding pressure
UP l/E I 11~ ~ 19 %
UP l/V distorted distorted
UP 2/E 1 44 ~ 60
UP 2/V 52 % 65 ~
UP ~/E 1 ~3 ~ 61 ~ `
Le A ~ 99
1a~55639
UP 3/V 62 70 7
UP 4/E I 4 7 % f;' 5
UP ~/V 55 $ 68 ~
__
All the UP/E 1 moulcling compositions show less rela-tive
shrinkage than the comparison samples UP/V. UP/E 1 shows
' the leas-t relat:ive shrinkage on nccoun-t of -the poor styrene
:. compatibility ol the polyes-ter IJY 1.
S ~rel) of Group 2 (Variation of the ~raft-pol,ymerised '.
elastomers)
.
S (rel) 2
under 25 kp/om under 50 Isp/cm2
Exumples mould.ing pressuro moulding pressure
- --- _,
UP 3/E 1 43 $ 61
UP 3/E 2 46 % 56 %
UP 3/E 3 54 ~ 67 %
UP 3/V 62 ~ 70 ~0
All the snmples show less relative shrinlcage compared
with the comparison sample UP 3/V.
S ¢,rol~ Or Group 3 (Variation o:f ~ ntit~ of~ aft pol~1ner)
S rel
under 25 kp/cm2 2
Example moulding pressure under 50 kp cm
. _ . . . _ . . . _ .
25 UP l/E 11 28 % 55 %
UP l/E 1 14 % 19 %
UP l/E 12 23 ~ 33 %
UP l/E 13 32 ~0 48 %
Example UP l/E 1, with a graft polymer content of' 5
show lowest relative shrinkage. Smaller quantities of
UP l/E 11) and, in particular, larger quantities of graft
Le A 15 ~99 - 21 -
1~5~639
polymer UP l/E 13) produced distinctly higher relative
shrinlsa~e values.
S (rel) o~ Group 4 (Variation of the styrene ntent)
under 25 })sp/cm2 under 50 kp/cm2
Example moulding pressurc moulding pressure
. . .
UP ll/E 1 46 % 76 %
UP 12/E 1 23 ~ 49 ~o
UP l/E 1 14 % 19 %
~ UP 13/E 1 11 ~ 12 ~0
1 0
. . . ,_
These Examples show distinetly decreasing shrinkage
: values with increasing styrene oontent of the mixtures.
Le A 15 499 - 22 -
. .. , .. . ,:. .. ~ . :.. . . ~ . , : .. . . : . .
