Note: Descriptions are shown in the official language in which they were submitted.
CASE 1~80
Polycarbonate is a resin known to possess exceptional mechanical
characteristics9 pQrtisularly in terms of impaet stren~th~ but it
has certain dafeGts wllich prevent its use in many large-consumption
applications.
Of these defects9 the mairl ones are a substantial brittling beyond
a certain critical thicluness, a very low resistance to rnany organic
sol~ents~ and poor impact strength at lo~ temperatureO
I'hese negative characteristics have greatly limited the use of
polycarbolla-te in one field, namely the automobile field~ ~Jhich
although ~onstantly searching for ~ew materiAls of elevated
mechanical properties~ must ensure that they possess excellent
resistance to those agents (petrol, lubricants~ deterg~ellts etcO)
whieh are able, either habitually or accidentally, to come into
contact with the article dul-ing its operational lifeO
~he literature describes examples of blends preparecl by mi~in6 a
polycarbonate with a polyester (AU 55998~ US 49188,~147 US 31494~85)~
or by mixi.ng together a polycarbonate, a polyolefin and a third
con~onent such as an acrylic polymer (US 4~245~058)9 a hyclrogenated
bloclc copolymer (US 4~122,131) 9 or an epoxidisable polydiene
(GB 1~ 149,695)~
The literature also describes a thermoplastic polymer blend
(GB 17007,724) comprising at least 50% by ~eigrht of polycarbonate
and not more than 50,~ of an olefin polyrner which can be partially
substituted by a polyester resin9 such tha-t the wei~ht ratio of the
olefin polymer to the polyester is always greater than ~nityO
Howovert because o~ the substantial plasticising effect which
3~
..
polyolefins have on polycarbonate, this blend has a rather lo~J
load distortion temperature, this being a limiting char~cteristic
~or many applications, including the auto~obile field~
We have now surprisingly found that it is possible to prepare
materials with improved thermal properties by suitably mixin~
together bisphenol A polycarbonate, one or more thermoplastic
polyesters prepared by condensing terephthalic acid with glycols
of general formula ~O-(CH2~n-OH where ~ lies bet~een Z and 10~
and olefin el~stomers in such quantities that the weight ratio
o~ the o.efin elastomer to the thermoplastic polyeste~ is less
than or equal to 1,
Although the materials obtained have an impact strength which is
~ery close to that of polycarbonate, compared with this latter
they have excellent solvent resistance, lo~ sensitivity to tnick-
ness, impro~ed impact strength at low temperature; and easiermoulding conditions.
These polymer blends and the products obtained from them therefore
demonstrate physical9 chemical and electrical characteristics
which overall are better than those o~ polycarbonate when used
eithcr as such or in mixtures as described in the aforesaid
patents.
The present invention rela es to a three component thermo~lastic
polymer blend and to the materials obta~ned from it, and com~o~ises:
a) a bisphenoi A polycarbouate;
b) one or more polyalkyleneterephthalates in which the number of
c~rbor. atorls Or the alkylene radical is from 2 to 10; and
c) a modifier which r.!odifies the im?act ene~Dy a~sorpticn mec;l~nism~
6~3~
-- 3--
chosen from the following:
I) ~ C2 or C3 pal~olefin;
II) a C2-C3 olefin copolymer (e.g. of the EPR or EPD~ type);
III) a mixture o~ with (II~;
IV) a mixture of (I) with a copolymer of polyethylenevinyl-
acetate (E~) type; and
V) a mixture of (I), (II) and a copolymer of polyethylene-
vinylacetate (EVA) type,
such that the weight ratio of component c to component b is
less than or equal to 1.
The quantity of component a may vary between 5
and 95% by weight, the quantity of components b + c may vary
between 5 and 95~ by weight, and the weight ratio of component
c to component b, as indicated above, is less than or equal to 1.
The polycarbonate used is preferably chosen from
those having an intrinsic viscosity in methylene chloride at
20C of between 0.46 and 1.2 dl/g.
The modifiers of the impact energy absorption
mechanism used can be either simple polyethylenes or polypropyl-
enes, or copolymers of two or more ole-Eins such as EPR (ethyle-
ne-propylene) or EPDM (ethylene-propylene-diene), or mixtur-es
of these with a copolymer of the polyethylenevinylacetate (EVA)
type.
Although not essential, best results are obtained
by carrying out one or more premixing operations on the
components, then reducing the obtained blend to gxanules, and
then moulding the blend. The apparatus used for mixing is of
no special importance. ~hus single screw extrudeEs, double
screw extruders,Banbury mixers and all machinery normally used
in industrial practice are suitable
~,~
3~
for this ~urpose~
The thermoplastic pol~mer blend of the present invention caIi be
presen-ted i.n various forms such as powder~ granules~ spheres,
discoids or other ~orms, prepared for example either by extrusion
or by injeotion.
The blend c~n contain various ~dditives such as stabili.sers~ dyes,
.~lame retard~rs9 lubricants or ~illers (glass fibre~ carbon fibre,
asbestos fibre, glass wool etc~). All operationa.l details will
be apparent from reading the examples given hereil~fter, their
purpose being ~erel~ to illustrate the invelltion without limi.tirlg
it in any way~
EXA~IES 1_77
The blend component Oranules are clried and mixed, and extruded ilt
a single screw extruder at a temperature of 275Co
The pol~ller blenrl obtained in this manner is then granulated and
injection-moulded at temperatuLres varying between 260 and 2~0C
according to the composition, the mould temperature being 60C~
The follo~ing tests were carried out on tlle products obtained:
a) Izod notcned bar impact test (ASTM D 256 61 method)
b) Vicat softenin~ point at 5 kg ~ASTrl D 15X5 72 nlethod)
c~ Modulus of elasticity in bending ~STM D 790~70 method)
d) Stress cracking test:
tension is applied in accordance with the ASTM D 6~8 method
to sar~ples which have been pre~iousl~J subjected to 0.7~ ter~sile
~5 deform~tion and immersed for 2 hours in a l:l (volumetric)
~ ~tu~e o toluene and isooctane to which l~o of methyl alcohol
has been added.
3~
s
~he percent~gs retention of the ultimate tensile stress of
the non_irnmersed sam~le is then mea~ured.
TABLE 1
Comp~ltlon 1 2 3 4 5 6 7 8
PC 100 90 75 60 60 60 50 50 5Q
P~T ~ 5 15 35 3 20 45 40 25
~PR 5 10 5 10 20 5 10 25
Degrees ~loat
155 147 135 137 123 lQ~ 125 ~ 12 ~4
5 KG ( C~
IZOD IMPACT, I.~T~
59 63 67 78 ~1 51 54 62
(kg cm/c~
MOD. E~LASTICITY
2 23000 21~00 1970022300 20000 1530022800 20300133~0
IN BENDING ~kg/cm )
~ U~T~ TENSI~E STRESS
RETE.~rION AFTER 120 MIN. - 63 7~ 92 94 91 90 91 89
~ ERSICN
TA:13LE 2 -
~ompositio~ 13 11 12 13 14 15 16 17 18
PC 100 75 75 60 60 60 5~ -50 - 5~
- 20 15 35 30 ''O 45 4 25
EPl~M . - 5 10 5 l O 20 5 10 25
Degrees ~icat
155 14~ 133 13~ 121 105 1 21 ~ 09 90
5 KG (C)
IZOD IMPACr, N~;~
82 91 98 5~ 63 75
( kg cm/cm 3
MO~. ELASTICITY
23000218001 950022500 2~1001510~230002050013200
IN BE!~DT~ ~kg~cm 3
,~ VI.T. TENSTLE SlæSS
R~TENrION AFL'~R 12û MIN. -65 79 gO 95 93 93 94 87
IMI~IE~SION
TA3LE 3
Co~posit~ on 19 20 21 22 23 24 25 26 27 28 29 30
PC 1~0 75 75 60 ~0 60 50 50 50 40 40 4~
P13T _ 20 15 35 3~ 20 45 40 25 55 5 3
EPDM 10 5 10 20 5 10 25 10 10 3
Degree~ VS C2-t
1~ 135 12~133 124 115131 122 1~$ 138 ~ ~7 107
5 I~G ~ C)
IZOD IMPACT, NOTCHED
9Q 58 72 29 87 95 76 8~ 91 47 ~3 62
(3~g cm/cm)
MOD~ ELASTICITY
~ 23000 22900 20200 24000 ~130~ 15700 24300 21700 1360~ 24200 2180~ 11300
IN BE~)ING (~g/cm )
,g ULT. TENSILE STR}:SS
R~E~'TION AFr~ 120 MI~ 75 78 80 83 77 82 84 79 87 ao - 88
IM~SION
TAB~ 4
Colllpo~it~on 31 32 33 34 135 ~ 37 38 39 ~ 41 42
P~ lOû 75 7~ 50 60 60 50 50 50 4û L~0 40
PBT - 20 15 35 3 20 ~5 40 25 55 50 30
es l~cat
155 136 123~ 34 125 11~~ 35 12~ 1351 35 ~ 27 10g
5 I~G ( ~)
IZOD Il~'~A5T, ~iU~J3 t ~,
52 65 73 78 81 ,71 7g 8~ 40 45 51
(kg cm/cm) ~ g~
MO:D. ~ STICIT~
2 2300022700 2010024100 213001600023900215001370Q23100 215001' 7CU
IN BENDII`,'G (kg~cm )
~,~ U~T. ~S~ 'rRE~S
R~;TE:NTrO!~ AFTE~R 120 MIN.- 73 77 81 82 79 80 86 82 85 88 84
I~"MERSION
TA~L~3 5
Col~posltlon 43 44 45 46
PC lC0 75 ~o 50 - -
~0
PP - - 5 5 10
Degre~ Vicat
o 155 143 1~ 11 5
5 KG ~ C~
IZ013 I~PACT~ hV~
68 63 51
~g ~/CI!~ o ~
Mûl). EI A~TICI'rY
23~00221 00215~0 2û600
IN 3E~ING ~ cm )
,~ UI,T. T~NSII.E STBESS
R~l~NlL01~ AFTER 120 M~V. _ 75 85 ~9
IM-'Y~RSION
TABIE 6
Con~.positl on. ~7
P~ 100 60 5Q
4C -
PE - 5 10
Degrees ~lcat
5 ~G ~QC) ~55 741 114
IZOD II~PACT, N'OICHEI~
67 5
(kg cm~cm) ~
MOI 1o ELASTICT~Y c
- ~ 23S)0022000 20200
IN 13~NDING (k~/cm )
,~ ULT. TENSII,E STRESS
R~EI~rIûN AF~ 120 MIN. - 87 91
E RSION
TABI~i: 7
Compositlon 50 51 52
PC 100 60 5
L~o
-P - S 10
D~gree~ yi cat
155 138 12~;
5 R~
IZOD IMP~CT, NOT~D
72 7
~kg c.~n/cm) ~a
MOD. 3I~STICITY
Eh'DING (kg/cm ) 2300023700 Z1900
'~ U~T. TENSILE STRESS
REr};NTIOlq AFrEP~ 120 M~i. - 84 85
IM~;~SION
TA3LE 8
Composl~lon 53 j4 55
PC lOQ 60 50 -
Degrecs V1 cat
155 135 123
5 KG ~~:~
IZOD IMPACT,
76 71 , 1~
(kg c~n/c~.) li,O~ ~9
~OD. ELASTICITY &'
~ ~350~ 21500
lN B~NDING (kg~cm~)
,~ UIT. TENSILE STRESS
rIo~ AFTER ~ 20 MI~. ~ 87 89
I~RSION
TAi3~E 9
Co~ ltion 55 57 58 ~ 60 61 62 63 64 65 66
PC 80 50 ~0 50 80 50 ~0 5 5 5~ 60
:E~i3T 10 40 10 4~ 40 4 0
PE~ 10 L~o 10 ~0 30
EPDM 5 5 5 5 5 3 5 5
EPR
-~ 5 5 5 5 5 5
PP 5 5 5 5 5
E~rA 5 5 5 ~ ~3
D~gre~s ~ricz~ 5 KG(~C) 135 130 132 118 133 131 130 120 132 130 133 G3
IZOD IMPAC~ 63 71 54 59 60 65 53 58 62 58 66
~k~ c~!fcm)
MODo ELASTI~IT'f I~
~E~NDING ~kg/c~.2)2~ 5002010021200203002200021300214Q020700205002070019800
,~ I;LT. TE~!S T LE STP~S
RErEN~ION A~ER 120 7 83 76 90 6& 81 75 93 86 83 88
MIN . II~I~RS IOh'
Co~osltion 67 68 69 70 71 72 73 74 75 76 77
P~ ~ 5~ 5~ 50 ~0 6~ 60 50 ~0 60 60
PBT 40 ~0 40 4 4
~ET 3~ 3 3 3 ~ 3
EPD.~ 2.5 2.5 2~5 2.5
EPR 5 5 5 5 2.5 Z~5 2.5 2.5
P~ 5 5 2.5 2.5
PP 5 5 5 2-5 2,3
~VA 5 5 5 2.5 Z~5 2~5 2-5
~gr~es Ylcat 5 ~G ~C) 131 128 129 126 126 l27 124 130 129 127 128
IZGD IMP~CT~ Nu~ 5~ 67 65 56 66 61 57 69 65 71 73
(kg cm~c~)
MOD. EI~STICITY IN201002040Q2060019900Z0200 20300 19600 20700 20600 20200 2C400
DTI~ (k~/~m2?
,~v ULT. T3NSIL~ ST~ESS
RE~E.~rION hFT~R 120 gl 83 80 ~3 $~ 91 89 86 ~4 93 93
~sIN. ~ S, ~
The da-ta obtained from ex~ples l to 77 are sho~m on tablcs 1 t~ lO.
ABBREilIATIO~lS
PC polycarbonate
PET polyethylenet~erephthalate
EPR ethylene-propylene rubber
EP~M ethylene~propylene-diene monomer terpolymer
PBT polybutyleneterephthalate
PP polypropylene
PE polyethylene
EVA ethylene vinylace-tate copolymer.
