Note: Descriptions are shown in the official language in which they were submitted.
WO 93/20144 ~ PCI`/I~iL93/00068
`, i , :
P(:)LYMER COMPOSITION COMPRISING A MIXTURE OF A ~RYSTALLINE OR SEMI~
CRYSTALLINE POLYOLEFIN ANr) A POLYMER BASED ON VINYLAROMATI(:` ANI)
RBOXYLlC A~ ANHYr3Rll~E MONOMER UNITS
The invention relat~s to a polymer composition
comprising a mixture of a crystalline or semi-crystalline
polyolefin (A) and a polymer (B) based on vinyl-aromatic and
dicarboxylic acid anhydride monomer units.
A polymer composition of this type is known from
WO-A-9005759. In WO-A-9005759 a polymer mixture of a
crystalline or semi-crystalline polyole~in and a second
polymer, such as a copolymer of styrene and maleic
anhydride, is described. Since the polyolefin ancl the second
polymer are not miscible, the polymer mixture contains a
compatibiliser. According to this publication, the
compatibiliser is a block copolymer of a vinyl-aromatic -
compound and a conjugated diene or partially hydrogenated
derivatives thereof. Here and hereafter a compatibiliser is
understood to be a compound which improves the compatibility
of A and B and is primarily located at the interface of the `
polyolefin A and the polymer B.
It is known from JP-A-63.2050341 to use styrene-
containing rubber-like copolymers as compatibilisers in
polymer compositions consisting of polypropene and
styrene/maleic anhydride copolymers. A drawback of these
polymer compositions is, however, that the impact
strength/rigidity combinatisn (Izod vs. modulus of elas-
- ticity) is poor, as a result of which the polymer com-
positions are unsuitable for structural moulded components
which are used in, for example, cars and furniture.
The aim of the invention is to provide a polymer
composition of a~ polyolefin A and a polymer B based onvinyl-aromatic monomer units and dicarboxylic acid anhydride
WO93/201~ PCT/NL93/00068
, _ ~
monomer units, which has a good impact strength/rigidity
combination.
The invention is characterised in that the polymer
B is crosslinked. The crosslinking of the polymer B can be
either of the chemical or the physical type. Physical
crosslinking is effected under the influence of Van der
Waals forces, dipole-dipole interactions and ionogenic
interactions.
Polymer B can be chemically crosslinked by a
reaction with a compound which contains at least two
functional groups which are able to react with the
dicarboxylic acid anhydride group of the polymer.
A further advantage of the polymer composition
according to the invention is that the elongation at break
of the polymer composition increases.
Another advantage of the polymer composition
according to the invention is that the said composition also `
has good scratch resistance and paintability~
Compounds containing two or more alcohol or thiol
functional groups form a first group of possible compounds
suitable for crosslinking the polymer B. lhe combination of
alcohol and thiol functional groups in a compound is also
possible. Compounds containing two or more alcohol
functional groups, such as 1,4-butanediol, 1,6-hexanediol,
pentaerythritol, ethyiene glycol and propylene glycol and
polymers thereof are preferred. Polyhydroxy ethers can also
be used, for example polyhydroxy ethers based on bisphenol
A.
Compounds containing two or more primary or
secondary amine functional groups, preferably primary amine
groups, form a second group of compounds suitable for
crosslinking the polymer B. llhe following may be mentioned
as examples of these compounds containing amine functional
~roups: alkane diamines containing a C~-C20 alkylene group,
such as 1,4-diaminobutane and 1,6-diaminohexane, polyoxy-
ethylene diamine, polyoxypropylene diamine, polyoxypropylene
triamine, diphenyl sulphone diamine, 1,3-phenylene-diamine
WO93/201~ ~ J ~ ' PCT/NL93/()006X
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and 1,4-phenylene diamine. The combination of one or more
primary amine groups with one or more secondary amine groups
in a compound is possible. Polyamides can also be used. The
compound suitable for crosslinking the polymer B can also
contain at least one alcohol or thiol group and also at
least one amine group. Diethanolamine and monoethanolamine
are examples of this type of compound.
Compounds containing two or more epoxide functional
groups having the general formula: ~
:
( CR------CHR ) n .
\ O ~
-
in which n22 and R is a hydrocarbon radical or a hydrogen ;;
atom form a third group of compounds suitable for cross-
linking the polymer B. Examples of such compounds are: -
polyglycidyl ethers of polyhydroxyl-substituted compounds.
These compounds can be subdivided into polyepoxide compounds
of the aromatic type, such as can be obtained from bisphenol
A, and polyepoxide compounds of the aliphatic type, such as -
polyglycidyl ethers of polyalcohols. The following may be -
mentioned as examples of the latter type of polyepoxide
compounds: diglycidyl ethers of -~ diols, such as
butanediol diglycidyl çther, hexanediol diglycidyl ether,
paracyclohexyldimethanol diglycidyl ether, neopentyl glycol
di~lycidyl ether and bisphenol A diglycidyl ether.
Preferably, compounds are used which are the result of the
30 epoxidation of olefins, such as epoxidised soya oil. ~ -
When crosslinking with an epoxide compound it is
usually desirable to use an activator, such as an imidazole,
a quaternary ammonium salt or a tertiary amine.
- ~ Compounds containing 2 or more oxazoline groups
form a fourth group of compounds suitable for crosslinking
the polymer B. 1,3-phenylenebisoxazoline may be mentioned a~
an example of these compounds.
Compounds containing 2 or more isocyanate groups
form a fifth group of compounds suitable for crosslinking -`
WO93/201~ ; !? ~ 4 _ PCT/NL93/0006X
the polymer s. Examples of these compounds are toluene
2,4-diisocyanate, benzene 1,3,5-triisocyanate and
methanediphenyl diisocyanate.
Salts of metal atoms from groups 2-lO of the
Periodic System of the Elements (Handbook of Chemistry and
Physics, 70th Edition, CRC Press, 1989-1990) form a sixth
group of compounds suitable for crosslinking the polymer B.
Preferably, metal alkoxides and salts of divalent positive
ions are used, such as tetrabutoxytitanium, zinc oxide and
zinc acetate.
A compound containing two or more functional
groups, chosen from the abovementioned groups, is also
suitable for crosslinking the polymer B.
A mixture of compounds suitable for crosslinkinq
the polymer B, chosen from one or more of the abovementioned ~-
groups of compounds, can also be used.
The compound suitable for crosslinking the polymer
B is present in an amount of 0.1-20 mol~ with respect to the
amount of dicarboxylic acid anhydride groups present in
polymer B. ~`
Crystalline or semi-crystalline polyolefins A which `-
can be used in a polymer composition according to the
invention are homopolymers, copolymers or terpolymers or
mixtures thereo~. Polymers of -olefins are preferably used
and these -olefins generally have 2 to 20 carbon atoms. The
use of polymers of -olefins having 2-6 carbon atoms is
particularly preferred.
The crystalline or semi-crystalline polyolefins are
derived from olefins, such as ethylene, propylene, l-butene,
1-pentene, 4 methyl-1-pentene, l-octene, l-decene, 4-ethyl-
l-hexene, etc. Examples of particularly suitable polyolefins
- are: low density polyethylene, high density polyethylene,
linear low density polyethylene, ultra-low density poly-
ethylene, polypropylene, (high and low density) poly(l-
butene), poly(4-methyl-1-pentene), ethylene/propylene
copolymers and copolymers of ethylene and/or propylene with
other copolymerisable monomers, such as ethylene/l-butene
WO93/201~ PCT/NL93/00068
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copolymer, ethylene/vinyl acrylate copolymer or ethylene/-
vinyl acetate. Polymers and copolymers of halogenated
olefins can also be used.
An amount of 30-95 parts by weight of polyolefin A
is present in the polymer composition, based on the sum of
polyolefin A and polymer B. The amount of polyolefin is
preferably 60-80 parts by weight. The amount of polyolefin A
in the polymer composition can proportionally be lowered
when a functionalised polyolefin A is used as
compatibiliser (see below).
- Polymer B comprises vinyl-aromatic monomer units
and dicarboxylic acid anhydride monomer units. Suitable
vinyl-aromatic monomers for use in the polymer B are,- for
example, styrene, alpha-methyl-styrene, para-methylstyrene
and mixtures thereof. Styrene is preferably used.-
Suitable dicarboxylic acid anhydrides are, for ;~
example, maleic anhydride, chloromaleic anhydride, citraco-
nic anhydride, cyclohexylmaleic anhydrids, benzyl maleic
anhydride, phenyl maleic anhydride, aconitic anhydride,
propyl maleic anhydride and mixtures thereof. Maleic anhy-
dride (MA) is preferably used.
Polymer B preferably consists of styrene and maleic
anhydride and can contain 5-40 mol~ of maleic anhydride. In
particular, polymer B~contains 22-32 mol~ of maleic
anhydride.
Polymer B can also contain imide monomer units or
spirodilactone units. Imide monomer units which can be
30 present in polymer B are N-phenylmaleimide, maleimide, -~
citraconimide, itaconimide, aconimide, N-methylmaleimide or
mixtures thereof. The spirodilactone units can be formed by
heating the polymer B. The dicarboxylic acid anhydride
content of polymer B must remain at least 5 mol~.
Polymer B can be prepared by copolymerising the vinyl-
aromatic monomer units and the dicarboxylic acid anhydride
monomer units and/or the imide monomer units in a known
manner.
Imide units can also be obtained by reacting some
WO93/20~ PCT/~L93/00068
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of the dicarboxylic dcid anhydride units in the polymer B
with a primary amine or ammonia. Examples of amines which
can ~e used are: aniline and methylamine.
Polymer B is present in the polymer composition in
an amount of 5-70 parts by weight based on the sum of
polyolefin A and polymer B, preferably 20-40 parts by
weight.
The amount of polymer B in the polymer composition
can proportionally be lowered when a functionalised polymer
B is used as compatibiliser (see below).
- A functionalised polyolefin A and/or a functiona-
lised polymer B can be added to the polymer composition in
15 order to obtain an even better compatibility. To this end, a ~`
portion of the amount of polyolefin A or the amount of -~
polymer B present in the polymer mixture can be replaced by,
respectively, the functionalised polyolefin A or the
functionalised polymer B. The portion which can be replaced
is 0-lO0~, with a preference for 50-100~ for the replacement
of polymer B and a preference for 0.5-30% for the
replacement of polyolefin A. Combinations of the
functionalised polyolefins A and functionalised polymers B
can also be used.
A functionalised polyolefin A c- a functionalised
polymer B is understoQd to be: a polyolefin A or a polymer B
which contains groups which are compatible or reactive with,
respectively, the polymer B or the polyolefin A.
The functionalised polyolefin A contains one or
more functional groups, such as:
- a hydroxyl group, -
- a thiol group,
- an amine group,
- an amide group,
- an epoxide group,
- an oxazolîne group,
- an isocyanate group or
- an alkoxide group.
Preferably, the functional polyolefin A contains
WO93~201~ ~ PCT/NL93/00068
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one or more isocyanate groups, one or more oxazoline groups
or one or more amine groups.
The functionalised polymer B contains one or more
linear or branched alkyl ~roups with 10-200 carbon atoms.
The functionalised polyolefin A is, for example,
prepared starting from a polyolefin grafted with a
dicarboxylic acid or anhydride, like maleic anhydride or
acrylic acid. Such a grafted polyolefin preferably contains
0.01-10 parts by weight of anhydride groups or acid groups. -~
Preferably, the polyolefin is grafted with maleic anhydride
- or acrylic acid and contains 0.1-7% by weight of maleic
anhydride groups or acrylic acid groups.
The polyolefin grafted with an anhydride or with an
acid can hereafter be reacted with one or more of the
compounds listed below, or combinations of these compounds,
in order to obtain the functionalised polyolefin A. The
compound to be used contains 2 or more:
- hydroxyl-groups,
- thiol-groups,
- amine-~roups,
- amide-groups,
- epoxide-groups,
- oxazoline groups,
- isocyanate groups.
The compound can also be an alkoxide of a metal from group
4-13 of the Periodic System of the Elements (Handbook of
Chemistry and Physics, 70th Edition, CRC Press, 1989-1990).
Examples of such compounds are: 1,3-phenylene-
bisoxazoline, 1,4-phenylene diamine, 1,3-phenylene diamine,
methane-diphenyl diisocyanate, tetrabutyl titanate and
ethanolamine.
- During these reactions preferably at least 70~ of
the anhydride groups or acid groups are reacted.
Crosslinking of the functionalised polyolefin should be -
- avoided. Particularly prefered, 100~ of the anhydride or
acid groups are converted~
The functionalised polyolefin A can also be
WO93/201~ PCT/NL93/0006X
prepared by grafting non-functionalised polyolefin A with
for example hydroxyethyl methacrylate, glycidyl
methacrylate, acrylamide, isopropenyloxa~oline and dimethyl
methaisopropenyl benzylisocyanate.
The functionalised polymer B is, for example,
synthesised by grafting the polymer B with a compound which
contains a linear or branched alkylgroup with 10-200 carbon
atoms and having a terminal functional group which is able
to react with the dicarboxylic acid anhydride groups in the
polymer B. Preferably, 20-90~ of the dicarboxylic acid
- anhydride units are converted.
- The functionalised polymer B can be grafted with a
linear or branched alkyl compound containing as the terminal
functional group:
- a primary or secondary amine group,
- a primary alcohol group,
- a primary thiol group,
- an oxazoline group,
- an epoxide group and/or
- an isocyanate group. ~
These compounds are, for example: l-dodecylamine, 1-octa- -
decylamine, l-nonadecyl alcohol, epoxydodecane, OLOA 1200R
from Chevron (an amine-terminated polybutene having about 70 ~;
carbon atoms).
When grafting polymer B with an epoxide compound it
is usually necessary to use an activator, such as an imida-
zole, a quaternary ammonium salt or a tertiary amine.
Preferably, a compound which contains a linear or
branched alkylgroup with 10-200 carbon atoms and a primary
amine functional group is used as the compound for grafting -~
polymer B.
The grafting reactions are performed by known
methods for a person skilled in the art.
A polymer composition according to the invention
can also contain an elastomer or an elastomer-containing
composition as an impact modifier. Examples of suitable
elastomers or elastomer-containing compositions are~
WO93/201~ ~ ~` PCT/NL93/00068
_ g _ ~ .
polybutadiene, ethylene-propylene rubber (EPR),
ethylene-propylene-diene rubber (EPDM), functionalised EPDM,
acrylonitrile-butadiene-styrene copolymer (ABS),
acrylonitrile-ethylene-styrene copolymer (AES) and silicone
elastomer. 0-50~ by weight of the elastomer or of the
elastomer-containing composition can be added to the polymer
composition. Preferably, 0-30 parts by weight are added.
The polymer composition can be obtained by mixing
all components in arbitrary sequence. The polymer composi-
tion can preferably be obtained by dynamic crosslinking,
that is ~o say, the composition is mixed and/or kneaded,
with heating, in equipment customary for this purpose, for
example in a Brabender mixer or on rollers or in an
extruder. The polyolefin A, the polymer B and, where
appropriate, the compatibiliser are mixed at a temperature
at which all three of the materials flow readily. This
temperature is higher than the glass transition temperature
of the polymer B and higher than the glass transition
temperature or the melting point of the polyolefin ~,
depending on the polyolefin A used and the polymer B used.
It is preferred that the crosslinkin~ compound is
added after the polyolefin A and the polymer B have been
mixed well. The time which is needed to carry out the
crosslinking reaction varies with the compounding conditions
(such as temperature and shear rate) and the type of polymer
and crosslinking agent used. Suitable temperatures are
between the melting point of the polyolefin (175C for
polypropylene) and 300C, while specifically the limits are
180-260~C.
The polymer composition according to the invention
can also contain the customary additives, such as fibres,
fillers, plasticisers, flame retardants and stabilisers.
The invention is further illustrated with the aid
of the following examples, without being restricted thereto.
The Izod is determined in accordance with
ISO R180/4A (23C; measured parallel to the direction of
injection-moulding).
WO93/201~ ~ PCT/NL93/00068
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The modulus of elasticity is determined in
accordance with ISO 178 (23C; measured parallel to the
direction of injection-moulding).
The elongation at break is determined in accordance
with ISO 37-2 (23C),
Example 1
Mixtures of polypropylene (PP), styrene maleic acid
anhydride copolymer (SMA) and crosslinking agent were
prepared in a Berstorff twin-screw extruder. -~
Blending conditions: cylinder temperature 215-240C; screw
Be 07; speed of rotation 150 rpm; yield: 5 kg/h.
As reference, the same amounts of polypropylene and SMA were "~
mixed without crosslinking agent being added.
The polypropylene which was used is Stamylan P 8:3EOOR.
The SMA which was used is 5tapron 28110R (both products of
DSM).
The crosslinking agents used were 1.3 mol~ of 1,3-phenylene- ;-
bisoxazoline (PBO) from Takeda Chemicals and 1.5 mol% of
pentaerythritol (PTA) from Aldrich Chemie. The amount of
crosslinking agent which is added is related to the amount
of anhydride groups present in polymer B. `~
Sheets were prepared from these mixtures by means
of injection-moulding Properties were determined on these``~
sheets.
The results are shown in Table 1.
`` `,
'",'
WO93/201~ PCT/NL93/00068
TABLE 1
Without crosslinking agent
PP/SMA Izod Modulus ofElongation at
elasticitybreak
(parts by weight) (kJ/m2) (N/mm2) (~)
95/5 35.2 1320
90/10 12.4 1350
80/20 5.9 1490
70/30 3.0 1750 5.3
-15
With PBO ~
95/5 - 29.1 1300 -
90/10 ~1.7 1360 -
80/20 17.8 1480
70/30 8.5 1680 48.4
With PTA
70/30 9.3 1750 53.3
;~
It can clear;y be seen that over a broad range of
compositions the impact strength is increased by adding the
crosslinking agent to the mixture of polypropylene and SMA,
whilst the rigidity is largely retained in comparison with
the mixture of polypropylene and SMA without crosslinking
agent. The elongation at break also increases by adding the
crosslinking agent.
Comparative ExPeriment A
On the basis of JP-A-63.205.341 mixtures of
polypropylene, SMA and a compatibiliser were prepared. The
polypropylene and SMA type-Q are the same as were used in
Example 1.
WO93/201~ PCT/~L93/00068
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~ .;
The mixtures were prepared using the same process
as in Example 1. The sheets were injection-moulded.
The compatibilisers used were: `
A. Kraton G 1652~ (a styrene/ethylene/butene/styrene block
copolymer; product from Mitsui Petrochemical).
B. Kraton G 1702 XR (a styrene/ethylene/propene block `
copolymer; product from Mitsui Petrochemical).
C. Kraton FG 1901 XR (a maleic anhydride-modified
styrene/-olefin block copolymer; product from Mitsui
Petrochemical).
- ~he mixtures consist of PP/SMA/Kraton 63/27/10
15 TABLE 2 --
','~. ~
Kraton Izod Modulus of elasticity -~
type kJ/m2 N/mm
...
A 3.8 1470
B 4.6 1400
C 3.2 1460
- .
Compared with a crosslinked polypropylene/SMA
mixture containing 70~ by weight of polypropylene and 30% by
weight of SM~ according to Example 1, the mixtures
containing Kraton as compatibiliser show both a poorer
impact strength and a poorer rigidity.
Example II
Process for the preparation of an a-octadecylamine-
modified styrene/maleic anhydride copolymer.
150.0 g of Stapron 28110R (SMA) were dissolved in ~`-
1 dm3 of methyl ethyl ketone (MER) t with stirring and
heating under a N2 atmosphere. `";
28.6 g of ~-octadecylamine were then added to the
"',-'
~ ' ~
WO93/201~ ~ PCT/NL93/0006X
- 13 - .
solution. The mixture was then heated to 67C, with
stirring. After the amine had dissolved, the reaction
mixture was stirred for a further 5 hours at 67C under N2.
2.4 g of sodium acetate and 24 ml of acetic anhydride were
then added to the pale yellow, clear reaction mixture, after
which the mixture was stirred for 5~ hours at 80~ under N2.
After cooling to room temperature, the mixture was
coagulated in methanol. The precipitated SMA-g-Cl~H3 ~NH2 was
filtered off, washed with methanol and dried under vacuum at
6C~C~ 25% of the original amount of MA groups in the SMA had
been converted to imide groups (determined by FTIR and
elementary analysis).
30 parts by weight of the so obtained SMA-g-
Cl8H3~NX2 by the process described above were mixed with 70
parts by weight of Stamylan P 83ElOR (PP) under the
conditions indicated in Example 1~ The crosslinking agent
used was 1.3 mol~ of PBO~
TABLE 3 ~ -
Pp/sMA-g-cl~H37NH2 Izod Modulus of elasticity
(parts by weight) (kJ/m2) (N/mm2)
. .
70/30 13.1 1650
Compared with a mixture of 70 parts by weight of
polypropylene with 30 parts by weight of non~modified SMA
which has been crosslinked using PB0, as described in
- Example 1, the impact strength is even further improved.
