U.S. patent application number 14/420218 was filed with the patent office on 2015-06-25 for polymer mixtures with optimized toughness/stiffness ratio and optical properties.
The applicant listed for this patent is STYROLUTION EUROPE GMBH. Invention is credited to Philipp Bockmann, Michael Ishaque, Rolf Minkwitz, Norbert Niessner.
Application Number | 20150175795 14/420218 |
Document ID | / |
Family ID | 48916087 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150175795 |
Kind Code |
A1 |
Niessner; Norbert ; et
al. |
June 25, 2015 |
POLYMER MIXTURES WITH OPTIMIZED TOUGHNESS/STIFFNESS RATIO AND
OPTICAL PROPERTIES
Abstract
The invention relates to a polymer mixture made of
styrene/nitrile monomer copolymers and of graft copolymers based on
acrylate rubbers, and also to thermoplastic moulding compositions
and mouldings produced therefrom and use of these.
Inventors: |
Niessner; Norbert;
(Friedelsheim, DE) ; Ishaque; Michael; (Mannheim,
DE) ; Bockmann; Philipp; (Bad Durkheim, DE) ;
Minkwitz; Rolf; (Mannheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
STYROLUTION EUROPE GMBH |
Frankfurt am Main |
|
DE |
|
|
Family ID: |
48916087 |
Appl. No.: |
14/420218 |
Filed: |
August 6, 2013 |
PCT Filed: |
August 6, 2013 |
PCT NO: |
PCT/EP13/66440 |
371 Date: |
February 6, 2015 |
Current U.S.
Class: |
524/504 ; 525/70;
525/71 |
Current CPC
Class: |
C08L 25/12 20130101;
C08L 33/20 20130101; C08L 51/04 20130101; C08F 220/1804 20200201;
C08F 220/18 20130101; C08L 2205/03 20130101; C08L 25/12 20130101;
C08L 2205/025 20130101; C08F 220/1804 20200201; C08F 220/40
20130101; C08F 220/40 20130101; C08L 25/14 20130101; C08L 51/003
20130101; C08L 51/04 20130101 |
International
Class: |
C08L 51/00 20060101
C08L051/00; C08L 33/20 20060101 C08L033/20 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2012 |
EP |
12179673.4 |
Claims
1-10. (canceled)
11. A polymer mixture of polymer components A1 and A2 and/or A3:
A1: from 5 to 95% by weight of a copolymer A1 of A11: from 60 to
80% by weight of at least one styrene or styrene derivative A11,
A12: from 40 to 20% by weight of at least one ethylenically
unsaturated monomer A12 comprising a nitrile group, A13: from 0 to
20% by weight of at least one other, copolymerizable monomer A13;
A2: from 5 to 50% by weight of a graft copolymer A2 with median
particle size from 90 to 280 nm, of: A21: from 60 to 80% by weight
of at least one rubber-like graft base A21 with Tg<0.degree. C.
made of A211: from 70 to 99.9% by weight of at least one alkyl
acrylate A211, A212: from 0.1 to 0.6% by weight of at least one
allyl methacrylate A212, A214: from 0 to 29.9% by weight of at
least one other of the following copolymerizable monomers A214
selected from methyl methacrylate, ethyl methacrylate,
phenylmaleimide, acrylamide, and vinyl methyl ether, A22: from 20
to 40% by weight of at least one graft shell made of: A221: from 65
to 70% by weight of at least one vinylaromatic monomer A221, A222:
from 30 to 35% by weight of at least one polar, copolymerizable
unsaturated monomer A222; and/or A3: from 5-50% by weight of a
graft copolymer A3 with particle size from 300 to 600 nm, of: A31:
from 60 to 80% by weight of at least one rubber-like graft base A31
with Tg<0.degree. C. made of: A311: from 70 to 99.9% by weight
of at least one alkyl acrylate A311, A312: from 0.1 to 0.4% by
weight of at least one allyl methacrylate A312, A314: from 0 to
29.9% by weight of at least one other of the following
copolymerizable monomers A314 selected from methyl methacrylate,
ethyl methacrylate, phenylmaleimide, acrylamide, and vinyl methyl
ether, A32: from 20 to 40% by weight of at least one graft shell
made of: A321: from 65 to 70% by weight of at least one
vinylaromatic monomer A321, A322: from 30 to 35% by weight of at
least one polar, copolymerizable unsaturated monomer A322, where
the proportions by weight of polymer components A1, A2, and/or A3
give a total of 100% by weight.
12. The polymer mixture as claimed in claim 11, characterized in
that it also comprises auxiliaries and/or additives.
13. The polymer mixture as claimed in claim 11, characterized in
that the vinylaromatic monomer A221 and A321 is styrene,
.alpha.-methylstyrene or a mixture thereof.
14. The polymer mixture as claimed in claim 11, characterized in
that the polar monomer A222 and A322 is acrylonitrile,
methacrylonitrile or a mixture thereof.
15. The polymer mixture as claimed in claim 11, comprising: A1:
from 5 to 95% by weight of a copolymer A1 of A11: from 60 to 80% by
weight of styrene or .alpha.-methylstyrene A11, A12: from 40 to 20%
by weight of acrylonitrile A12, A2: from 5 to 50% by weight of a
graft copolymer A2 with median particle size from 90 to 280 nm, of
A21: from 60 to 80% by weight of a rubber-like graft base A21 with
Tg<0.degree. C. made of A211: at most 99.9% by weight of at
least one alkyl acrylate having from 1 to 8 carbon atoms in the
alkyl moiety A211, A212: from 0.1 to 0.6% by weight of allyl
methacrylate A212, A22: from 20 to 40% by weight of at least one
graft shell made of: A221: from 65 to 70% by weight of styrene or
.alpha.-methylstyrene A221, A222: from 30 to 35% by weight of
acrylonitrile A222, and/or A3: from 5-50% by weight of a graft
copolymer A3 with particle size from 300 to 600 nm, of A31: from 60
to 80% by weight of at least one rubber-like graft base A31 with
Tg<0.degree. C. made of A311: at most 99.9% by weight of at
least one alkyl acrylate having from 1 to 8 carbon atoms in the
alkyl moiety A311, A312: from 0.1 to 0.5% by weight of allyl
methacrylate A312 A32: from 20 to 40% by weight of at least one
graft shell made of: A321: from 65 to 70% by weight of styrene or
.alpha.-methylstyrene A321, A322: from 30 to 35% by weight of
acrylonitrile A322, where the ratio by weight of component A2 to
component A3 (if both are present) is from 3:1 to 1:1, and the
proportions by weight of polymer components A1, A2, and/or A3 give
a total of 100% by weight.
16. The polymer mixture of polymer components A1, A2, and A3 as
claimed in claim 11, characterized in that: from 0.4 to 0.5% by
weight of allyl methacrylate A212 and from 0.1 to 0.2% by weight of
allyl methacrylate A312 are used.
17. A molding produced from a polymer mixture as claimed in claim
11.
18. A method of using moldings as claimed in claim 17 for outdoor
applications.
19. A process for the production of the polymer mixtures as claimed
in claim 11, by mixing polymer components A1and A2, and/or A3, and
optionally additional auxiliaries and additives.
Description
[0001] The invention relates to a polymer mixture of
styrene/nitrile-monomer copolymers and of graft copolymers based on
acrylate rubbers, and also to thermoplastic molding compositions
produced therefrom, and moldings, and use of these.
[0002] Impact-resistant thermoplastic compositions are often
obtained by adding graft rubbers to the polymers that form the
matrix, these being brittle at room temperature. The production of
these impact modifiers has been known for a long time and is
described by way of example in DEA 1260135, DEA 2311129, and DE-A
2826925. If the matrix is composed of polystyrene or of styrene
copolymers, the effectiveness of the graft copolymers in respect of
their impact-modifying action can be seen to increase as the size
of the graft copolymers increases. Another problem with use of
small-particle graft rubbers is that the toughness of the
impact-modifying compositions is greatly dependent on the
processing temperature.
[0003] Polymeric compositions which have improved impact resistance
and retain the same good colorability can be obtained by adding a
large-particle rubber component to a small-particle rubber
component (bimodal rubber particles), as described in DE-A 2826925.
The impact resistance, in particular the low-temperature impact
resistance, achieved in those compositions is frequently inadequate
for high stress levels. There are moreover restrictions on the
quantity of the large-particle rubber that can be added in order to
increase impact resistance; if these restrictions are ignored
colorability is markedly impaired.
[0004] It is known that the properties of the soft acrylate phase
can be improved if the soft polymeric phase comprises at least one
crosslinking agent. U.S. Pat. No. 4,876,313 describes what are
known as "core-shell" polymers obtainable via emulsion
polymerization, comprising various crosslinking agents. Alkyl
(meth)acrylates or styrene are preferably used as "core monomer",
and methyl methacrylate and methacrylic acid are preferably used as
"shell monomer". Among the preferred crosslinking agents is allyl
(meth)acrylate in a quantity of from 1 to 10% by weight, based on
the "core monomer". The core-shell polymers can be mixed with other
multistage acrylic emulsions.
[0005] It is known that impact-resistant multiphase emulsion
polymers of the ASA (acrylonitrile-styrene-acrylate) type have a
particularly balanced property profile when the soft acrylate phase
comprises at least one crosslinking agent.
[0006] EP-A 0535456 describes a thermoplastic molding composition
with improved impact resistance comprising a styrene/acrylonitrile
copolymer and a multishell graft copolymer, the core and the first
graft shell of which have been crosslinked with from 0.1 to 10% by
weight, preferably from 1 to 4% by weight, of a crosslinking agent,
in particular dicyclopentadienyl acrylate. By way of example, graft
copolymers are described in which the crosslinked core is made of
polystyrene, the first crosslinked shell is made of butyl acrylate,
the second shell is made of styrene, and the third shell is made of
styrene and acrylonitrile.
[0007] DE-A 4006643 describes a thermoplastic molding composition
made of a styrene/acrylonitrile copolymer or of an
.alpha.-methylstyrene-acrylonitrile copolymer, and of a particulate
graft copolymer. The graft base is a crosslinked acrylate rubber
with particle size from 30 to 1000 nm. A number of
polyethylenically unsaturated monomers are listed as crosslinking
agents, including allyl methacrylate. Preferred crosslinking agent,
and the only crosslinking agent used, is the acrylic ester of
tricyclodecenyl alcohol (DCPA). The quantity of the crosslinking
agent is from 0.1 to 5% by weight, preferably from 1 to 4% by
weight. The graft shell is preferably made of from 45 to 80% by
weight of styrene or .alpha.-methylstyrene and from 10 to 30% by
weight of acrylonitrile.
[0008] The prior art cited shows that the materials can comprise
various quantities of the crosslinking agents. Application of the
crosslinker quantities mentioned in the prior art to ASA molding
compositions with markedly different particle sizes is frequently
successful only with significant losses of impact resistance. The
relationship between the ideal quantities of crosslinking agents in
impact-modified ASA molding compositions and the particle size
thereof is not clear.
[0009] DE-A 2826925 describes a weathering-resistant,
impact-resistant thermoplastic composition with good colorability,
composed of a graft copolymer along with a hard component made of
styrene/acrylonitrile copolymers.
[0010] The graft copolymer is composed of two graft copolymers
produced separately, each of which is composed of a crosslinked
acrylate graft base and of a shell made of acrylonitrile/styrene
copolymers, where the particle size of the graft base of the first
graft copolymer is from 50 to 150 nm and that of the second graft
copolymer is from 200 to 500 nm. Preferred crosslinking agent, and
the only crosslinking agent used, is the acrylic ester of
tricyclodecenyl alcohol. The quantity of the crosslinking agent is
from 0.5 to 10% by weight, preferably from 1 to 5% by weight.
[0011] DE-A 4131729 describes a thermoplastic molding composition
with improved low-temperature toughness made of a
styrene/acrylonitrile copolymer or of an
.alpha.-methylstyrene-acrylonitrile copolymer and of a mixture of
particulate graft copolymers A and B with particle size from 50 to
200 nm and from 200 to 1000 nm. The graft bases A1 and B1 are
various crosslinked acrylate rubbers. A number of polyethylenically
unsaturated monomers are listed as crosslinking agents. Preferred
crosslinking agent, and the only crosslinking agent used, is the
acrylic ester of tricyclodecenyl alcohol (DCPA). The quantity of
the crosslinking agent is from 0.1 to 5% by weight, preferably from
0.2 to 4% by weight, for example 2% by weight. The graft shell is
preferably made of from 45 to 80% by weight of styrene or
.alpha.-methylstyrene and from 10 to 30% by weight of
acrylonitrile.
[0012] EP-A 1 893 659 likewise describes molding compositions based
on ASA resins with an elastomeric phase and a thermoplastic phase.
The elastomeric phase is a rubber substrate based on an alkyl
(meth)acrylate monomer and on at least one crosslinking agent. Many
polyethylenically unsaturated monomers are listed as crosslinking
agents. Preferred crosslinking agent, and the only crosslinking
agent used, is triallyl cyanurate. A portion of the thermoplastic
hard phase, which preferably comprises a styrene/acrylonitrile
copolymer or a styrene/acrylonitrile/methyl methacrylate copolymer,
has been grafted onto the elastomeric rubber phase. The elastomeric
phase can comprise two or more rubber substrates with various
particle sizes in the range from 50 to 1000 nm (measured
ungrafted), in particular in the range from 80 to 500 nm. One
embodiment uses an excess of the rubber substrate having relatively
fine particles.
[0013] The abovementioned molding compositions have improved gloss
and reduced haze, but mechanical properties, in particular at low
temperatures, still require improvement. It is an object of the
present invention to provide thermoplastic compositions which
especially at low temperatures below 0.degree. C., preferably
irrespective of the processing temperature, have better impact
resistance and stress-cracking-corrosion behavior, and in
particular better multiaxial toughness values. The gloss of the
molding composition should moreover be improved or at least
maintained.
[0014] The object is achieved via the polymer mixtures of the
invention.
[0015] The invention provides polymer mixtures made of the
following polymer components A1 and A2, and/or A3, Polymer mixtures
provided are therefore those made of polymer components A1 and A2,
those made of polymer components A1 and A3, and also those made of
polymer components A1 and A2 and A3, and in particular the
following quantity ranges can be used here:
[0016] A1: from 5 to 95% by weight of a copolymer A1 of:
[0017] A11: from 60 to 80% by weight of at least one styrene or
styrene derivative A11,
[0018] A12: from 40 to 20% by weight of at least one ethylenically
unsaturated monomer A12 comprising a nitrile group,
[0019] A13: from 0 to 20% by weight of at least one other,
copolymerizable monomer A13;
[0020] A2: from 5 to 50% by weight of a graft copolymer A2 with
median particle size from 90 to 280 nm, of:
[0021] A21: from 60 to 80% by weight of at least one rubber-like
graft base A21 with Tg<0.degree. C. made of
[0022] A211: from 70 to 99.9% by weight of at least one alkyl
(meth)acrylate A211,
[0023] A212: from 0.2 to 0.8% by weight of at least one allyl
(meth)acrylate A212,
[0024] A213: from 0 to 2% by weight of at least one other monomer
A213 having at least 2 unconjugated ethylenic double bonds,
[0025] A214: from 0 to 29.9% by weight of at least one other
copolymerizable monomer A214,
[0026] A22: from 20 to 40% by weight of at least one graft shell
made of:
[0027] A221: from 65 to 70% by weight of at least one vinylaromatic
monomer A221,
[0028] A222: from 30 to 35% by weight of at least one polar,
copolymerizable unsaturated monomer A222,
[0029] A223: from 0 to 30% by weight of at least one other,
copolymerizable monomer A223; and/or
[0030] A3: from 5-50% by weight of a graft copolymer A3 with
particle size from 300 to 600 nm, of:
[0031] A31: from 60 to 80% by weight of at least one rubber-like
graft base A31 with Tg<0.degree. C. made of
[0032] A311: from 70 to 99.9% by weight of at least one alkyl
(meth)acrylate A311,
[0033] A312: from 0.1 to 0.5% by weight of at least one allyl
(meth)acrylate A312
[0034] A313: from 0 to 2% by weight of at least one other monomer
A313 having at least 2 unconjugated ethylenic double bonds,
[0035] A314: from 0 to 29.9% by weight of at least one other
copolymerizable monomer A314,
[0036] A32: from 20 to 40% by weight of at least one graft shell
made of:
[0037] A321: from 65 to 70% by weight of at least one vinylaromatic
monomer A321,
[0038] A322: from 30 to 35% by weight of at least one polar,
copolymerizable unsaturated monomer A322,
[0039] A323: from 0 to 30% by weight of at least one other,
copolymerizable monomer A323.
[0040] The ratio by weight of component A2 to component A3 is often
from 3:1 to 1:1. The proportions by weight of polymer components
A1, A2, and/or A3 are intended to give a total of 100% by
weight.
[0041] The respective ratios by weight in the polymer mixtures are
often by way of example: [0042] a) of A1 and A2 from 65:35 to
75:25, often 70:30, [0043] b) of A1 and A3 from 65:35 to 75:25,
often 70:30, and [0044] c) of A1, A2, and A3 about 70:20:10.
[0045] The expression (meth)acrylate monomers means methacrylate
monomers and acrylate monomers.
[0046] The polymer mixtures of the invention can also comprise
auxiliaries and/or additives in addition to polymer components A1,
A2, and/or A3. Preference is given to mixtures of the invention
composed of from 50 to 99.9% by weight, preferably from 70 to 99.9%
by weight, of components A1, A2, and/or A3, and from 0.1 to 50% by
weight, preferably from 0.1 to 30% by weight, of the auxiliaries
and/or additives.
[0047] Preference is further given to those polymer mixtures which
comprise polymer components A1, A2, and A3.
Component A1
[0048] Quantities used of component A1 are from 5 to 95% by weight,
preferably from 10 to 90% by weight, in particular from 30 to 80%
by weight, very particularly preferably from 50 to 80% by
weight.
[0049] Suitable monomers A11 are styrene and styrene derivatives
such as .alpha.-methylstyrene and ring-alkylated styrenes, for
example p-methylstyrene and/or tert-butylstyrene. Preference is
given to styrene, .alpha.-methylstyrene, and/or p-methylstyrene, in
particular styrene and/or .alpha.-methylstyrene, and very
particular preference is given to use of styrene.
[0050] Monomers A12 used are preferably acrylonitrile and/or
methacrylonitrile. Acrylonitrile is particularly preferred.
[0051] The proportion of the monomer A11 in the copolymer A1 is
generally from 60 to 80% by weight, preferably from 60 to 65% by
weight.
[0052] The proportion of the monomer A12 in the copolymer A1 is
generally from 40 to 20% by weight, preferably from 40 to 35% by
weight.
[0053] The copolymer A1 can moreover also comprise up to 20% by
weight of at least one other, copolymerizable monomer A13, for
example methyl acrylate, ethyl acrylate, propyl acrylate, methyl
methacrylate, ethyl methacrylate, phenylmaleimide, maleic
anhydride, acrylamide, and/or vinyl methyl ether.
[0054] Preferred copolymers A1 are copolymers of styrene and
acrylonitrile and/or copolymers of .alpha.-methylstyrene and
acrylonitrile. It is particularly preferable that A1 is a copolymer
of styrene and acrylonitrile.
[0055] A1 can be produced by well-known methods (DE-A 31 49 358, p.
9, lines 18 to 32 and DE-A 32 27 555, p. 9, lines 18 to 32), for
example by well-known copolymerization of A11, A12, and optionally
A13 in bulk, solution, suspension, or aqueous emulsion at
conventional temperatures and pressures in known apparatuses
(reference Kunststoff-Handbuch [Plastics handbook],
Vieweg-Daumiller, volume V (Polystyrol [Polystyrene]),
Carl-Hanser-Verlag, Munich 1969, p. 124, lines 12 ff.).
Component A2
[0056] Monomers A211 that can be used for the production of the
rubber-like graft base A21 are generally alkyl (meth)acrylates
having a straight-chain or branched alkyl moiety having from 1 to
12 carbon atoms, preferably from 2 to 8 carbon atoms, particularly
preferably from 4 to 8 carbon atoms. Preference is given to alkyl
acrylates having a straight-chain or branched alkyl moiety having
from 1 to 12 carbon atoms, preferably from 2 to 8 carbon atoms,
particularly preferably from 4 to 8 carbon atoms, in particular
n-butyl acrylate and/or ethylhexyl acrylate. Production of the
graft base A21 can use the alkyl (meth)acrylates individually or in
a mixture.
[0057] The rubber-like graft base A21 also comprises from 0.2 to
0.8% by weight, preferably from 0.2 to 0.6% by weight, in
particular from 0.4 to 0.5% by weight, of at least one allyl
(meth)acrylate A212 as monomer component. Allyl methacrylate is
preferred.
[0058] A212 acts as crosslinking agent. The expression crosslinking
agents means at least bifunctional monomers having at least two
reactive, unsaturated groups.
[0059] The rubber-like graft base A21 can moreover comprise up to
2% by weight, preferably up to 1% by weight, and in particular up
to 0.5% by weight, of other copolymerizable monomers A213 having at
least 2 ethylenic double bonds which are not conjugated in
1,3-position and which likewise function as crosslinking agent.
Examples of suitable monomers A213 are divinylbenzene, diallyl
maleate, diallyl fumarate, and/or diallyl phthalate, triallyl
cyanurate, and preferably the acrylic ester of tricyclodecenyl
acrylate (=dicyclopentadienyl acrylate (DCPA)).
[0060] It is preferable that the graft base A21 comprises no
crosslinking agent A213.
[0061] Examples of possible other copolymerizable monomers A214
that can be used are the following compounds: alpha-methylstyrene,
methacrylonitrile, methyl acrylate, ethyl acrylate, propyl
acrylate, methyl methacrylate, ethyl methacrylate, phenylmaleimide,
acrylamide, vinyl methyl ether. It is preferable that the graft
base A21 comprises no monomer A214.
[0062] Monomers A221 suitable for the production of the graft shell
A22 are vinylaromatic monomers such as styrene and/or styrene
derivatives, for example alkylstyrene, preferably
.alpha.-methylstyrene, and ring-alkylated styrenes, for example
p-methylstyrene and/or tert-butylstyrene.
[0063] Preference is given to styrene and/or .alpha.-methylstyrene,
particularly styrene.
[0064] Examples of polar copolymerizable unsaturated monomers A222
are acrylonitrile and/or methacrylonitrile, preferably
acrylonitrile.
[0065] Examples of possible other copolymerizable monomers A223
that can be used are the following compounds: acrylic acid,
methacrylic acid, maleic anhydride, methyl acrylate, ethyl
acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate,
phenylmaleimide, acrylamide, and vinyl methyl ether. It is
preferable that A223 is methyl methacrylate and/or maleic
anhydride.
[0066] It is preferable that the graft shell A22 is a copolymer of
styrene and/or .alpha.-methylstyrene and acrylonitrile, preferably
of styrene and acrylonitrile.
Component A3
[0067] Monomers A311, A312, A313 and A314 used for the graft base
A31 are the corresponding compounds described above for the graft
base A21 (A211, A212, A213, and A214).
[0068] However, the quantity used of monomer component A312, i.e.
allyl (meth)acrylate, is from 0.1 to 0.5% by weight, preferably
from 0.1 to 0.4% by weight, in particular from 0.1 to 0.2% by
weight.
[0069] Monomers A321, A322 and A323 used for the graft shell A32
are likewise the corresponding compounds described above for the
graft shell A22 (A221, A222 and A223).
[0070] In one preferred embodiment the polymer mixture of the
invention made of polymer components A1 and A2 and/or A3
comprises:
[0071] A1: from 5 to 95% by weight of a copolymer A1 of
[0072] A11: from 60 to 80% by weight of styrene or
.alpha.-methylstyrene A11,
[0073] A12: from 40 to 20% by weight of acrylonitrile A12,
[0074] A2: from 5 to 50% by weight of a graft copolymer A2 with
median particle size from 90 to 280 nm, of
[0075] A21: from 60 to 80% by weight of a rubber-like graft base
A21 with Tg<0.degree. C. made of
[0076] A211: from 70 to 99.9% by weight of at least one alkyl
acrylate having from 1 to 8 carbon atoms in the alkyl moiety
A211,
[0077] A212: from 0.2 to 0.8% by weight of allyl methacrylate
A212,
[0078] A22: from 20 to 40% by weight of at least one graft shell
made of:
[0079] A221: from 65 to 70% by weight of styrene or
.alpha.-methylstyrene A221,
[0080] A222: from 30 to 35% by weight of acrylonitrile A222,
and/or
[0081] A3: from 5-50% by weight of a graft copolymer A3 with
particle size from 300 to 600 nm, of
[0082] A31: from 60 to 80% by weight of at least one rubber-like
graft base A31 with Tg<0.degree. C. made of
[0083] A311: from 70 to 99.9% by weight of at least one alkyl
acrylate having from 1 to 8 carbon atoms in the alkyl moiety
A311,
[0084] A312: from 0.1 to 0.5% by weight of allyl methacrylate
A312,
[0085] A32: from 20 to 40% by weight of at least one graft shell
made of:
[0086] A321: from 65 to 70% by weight of styrene or
.alpha.-methylstyrene A321,
[0087] A322: from 30 to 35% by weight of acrylonitrile A322,
[0088] where the ratio by weight of component A2 to component A3
(if both are present) is from 3:1 to 1:1, and the proportions by
weight of polymer components A1, A2, and/or A3 give a total of 100%
by weight.
[0089] Preference is further given to polymer mixtures of the
invention comprising components A1, A2, and A3 which comprise a
quantity of from 0.2 to 0.6% by weight, in particular from 0.4 to
0.5% by weight, of A212 and from 0.1 to 0.4% by weight, in
particular from 0.1 to 0.2% by weight, of A312.
[0090] The production of graft copolymers made of an elastomeric
rubber-like graft base and of a graft shell is well known (see by
way of example DE 4006643 A1, p. 2, line 65 to p. 3, line 43; DE
4131729 A1 p. 3, line 12 to p. 4, line 49).
[0091] Fine-particle graft copolymers can be produced by way of
example as described in DE 4006643 A1 (p. 2, line 65 to p. 3, line
43).
[0092] Coarse-particle graft copolymers can be produced via
grafting in two stages as described in DE 3227555 A1 (component B:
p. 8, line 14 to p. 10, line 5) and DE-A 31 49 358 (p. 8, line 14
to p. 10, line 5).
[0093] Production of the graft copolymers A2 generally begins with
production, for example by emulsion polymerization, of the
rubber-like acrylate polymer A21 serving as graft base, in that by
way of example alkyl acrylate A211 and the crosslinking agent A212,
and optionally A213 and/or A214 are polymerized in aqueous emulsion
in a manner known per se at temperatures of from 20 to 100.degree.
C., preferably from 50 to 80.degree. C. On this resultant
polyacrylate latex it is possible to graft a mixture of
vinylaromatic monomers A221 with a polar copolymerizable
unsaturated monomer A222 and also optionally other monomers A223,
and this graft copolymerization is preferably likewise carried out
in aqueous emulsion.
[0094] The production of the graft copolymers A3 proceeds, for the
graft base A31, as described above for A2, but the grafting usually
proceeds in two stages where the vinylaromatic monomer A321 is
generally first polymerized in the presence of the graft base A31.
The graft copolymerization with a mixture comprising at least one
vinylaromatic monomer A321 and at least one polar copolymerizable
monomer A322, and also optionally A323, can then be carried out in
the second stage.
[0095] The quantities of the various components used and comprised
in the polymer mixture of the invention have already been described
in the introduction.
[0096] The polymerization process can moreover use the conventional
auxiliaries and/or additives, for example emulsifiers, such as
alkali metal salts of alkyl- or alkylarylsulfonic acids, alkyl
sulfates, fatty alcohol sulfonates, salts of higher fatty acids
having from 10 to 30 carbon atoms, or resin soaps, polymerization
initiators, for example conventional persulfates such as potassium
persulfate, or known redox systems, polymerization auxiliaries, for
example conventional buffer substances that can be used for
adjustment to pHs that are preferably from 6 to 9, e.g. sodium
bicarbonate and/or sodium pyrophosphate, and/or molecular-weight
regulators, for example mercaptans, terpinols, and/or dimeric
.alpha.-methylstyrene, where the usual quantity used of the
molecular-weight regulators is from 0 to 3% by weight, based on the
weight of the reaction mixture.
[0097] The polymer mixture of the invention is produced by
incorporating the particulate graft polymers A2 and/or A3 described
above into the hard component, i.e. the copolymer A1. The method of
incorporation can by way of example be that the particulate graft
polymer is isolated from the emulsion by adding an electrolyte and
then, optionally after drying, is mixed with the hard component by
extruding, kneading, or roll-milling the materials together. The
auxiliaries and/or additives below can also be added during the
production of this mixture.
[0098] The material can comprise by way of example the following as
auxiliaries and/or additives: plasticizers, antistatic agents,
light stabilizers, lubricants, blowing agents, adhesion promoters,
and optionally other compatible thermoplastics, fillers,
surface-active substances, flame retardants, dyes and pigments,
stabilizers with respect to oxidation, hydrolysis, light, heat, or
discoloration, and/or reinforcing agents.
[0099] Light stabilizers used can be any of the conventional light
stabilizers, for example compounds based on benzophenone, on
benzotriazole, on cinnamic acid, on organic phosphites and
phosphonites; other examples are sterically hindered amines.
[0100] Examples of lubricants are hydrocarbons such as oils,
paraffins, PE waxes, PP waxes, fatty alcohols having from 6 to 20
carbon atoms, ketones, carboxylic acids such as fatty acids,
montanic acid, or oxidized PE wax, carboxamides, and also
carboxylic esters, e.g. with the alcohols ethanol, fatty alcohols,
glycerol, ethanediol, pentaerythritol, and long-chain carboxylic
acids as acid component.
[0101] Stabilizers used can be conventional antioxidants, for
example phenolic antioxidants, e.g. alkylated monophenols, esters
and/or amides of
.beta.-(3,5-di-tert-butyl-4-hydroxy-phenylpropionic acid, and/or
benzotriazoles. Possible antioxidants are mentioned by way of
example in EP-A 698637 and EP-A 669367. Specifically, mention may
be made of the following as phenolic antioxidants:
2,6-di-tert-butyl-4-methylphenol, pentaerythrityl
tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and
N,N'-di(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine.
The stabilizers mentioned can be used individually or in
mixtures.
[0102] Other compatible thermoplastics can by way of example be
polyesters (e.g. polyethylene terephthalate, polybutylene
terephthalate), PMMA, polycarbonate, polyamide, polyoxymethylene,
polystyrene, polyethylene, polypropylene, polyvinyl chloride.
[0103] These auxiliaries and/or additives can either be used before
production of thermoplastic component A1 concludes or else added to
component A1, A2, and/or A3 during the production of the
mixture.
[0104] The invention further provides moldings produced from the
polymer mixtures of the invention.
[0105] The polymer mixtures of the invention can by way of example
be pelletized or granulated, or processed by well-known processes,
for example by extrusion, injection molding, blow molding, or
calendering to give moldings of any type, for example cable
sheathing, foils, hoses, fibers, profiles, shoe shells, shoe soles,
technical moldings, consumer items, coatings, bellows, and/or ear
tags for animals.
[0106] A feature of the polymer mixtures of the invention, in
particular at low temperatures in the range from 0 to -30.degree.
C., is an optimized toughness/stiffness ratio with retention of
gloss.
[0107] The polymer mixtures of the invention can therefore be used
particularly advantageously for the production of moldings that are
used in the low-temperature range from 0 to -30.degree. C. By way
of example, without any restriction thereto, mention may be made in
this connection of outdoor applications, e.g. in the automobile or
construction sector.
[0108] The invention provides the production of the polymer
mixtures via mixing of the components.
[0109] The invention therefore further provides the use, for
outdoor applications, of moldings produced from the polymer
mixtures of the invention.
[0110] The polymer mixtures and applications of the invention are
described in more detail with reference to the examples and claims
below.
Examples
[0111] The parameters described in the present application were
determined as follows:
[0112] Notched impact resistance and impact resistance
(kJ/m.sup.2): measured in accordance with DIN 53 453 (ISO 179 1eA)
on injection-molded standard small specimens at 23, 0, and
-30.degree. C., and with an injection-molding temperature of
220.degree. C. In each case, three series of samples were tested.
Tables 3-5 collate the results.
[0113] Median particle size is determined by using an
ultracentrifuge and the method of W. Scholtan and H. Lange,
Kolloid-Z. and Z. Polymere 250 (1972), 782-796. The ultrafuge
measurement gives the cumulative mass distribution of the particles
of a sample. The median particle diameter d50 is defined as
follows: the diameter of 50% by weight of particles is smaller
than, and the diameter of 50% by weight of the particles is greater
than, the d50 value.
[0114] Puncture is determined in accordance with ISO
6603-2/40/20/c.
[0115] Gloss is measured at 60.degree. in accordance with DIN
67530.
[0116] Modulus of elasticity is determined in accordance with ISO
527-2:1993.
[0117] MVR (220/10) is determined in accordance with ISO 1133.
[0118] Component A1: Copolymer produced with 67% by weight of
styrene as A11 and 33% by weight of acrylonitrile as A12, IV;
intrinsic viscosity (measured in 0.5% toluene solution at room
temperature): 80 ml/g.
[0119] Component A1 was produced by a solution polymerization
process as described by way of example in: Kunststoff-Handbuch
[Plastics handbook], ed. Vieweg-Daumiller, volume V (Polystyrol
[Polystyrene]), Carl-Hanser-Verlag, Munich, 1969, p. 124, line 12
ff.
Component A2
Production of the Graft Base
[0120] The respective graft base was produced in accordance with
the following general specification: 160 g of the monomer mixture
stated in table 1 were heated, with stirring, to 60.degree. C. in
1500 g of water with addition of 5 g of sodium salt of a C.sub.12-
to C.sub.18-paraffinsulfonic acid, 3 g of potassium
peroxodisulfate, 3 g of sodium hydrogen-carbonate, and 1.5 g of
sodium pyrophosphate. 10 minutes after the start of the
polymerization reaction, a further 840 g of the monomer mixture of
table 1 were added within a period of 3 hours. Once monomer
addition had ended, the emulsion was kept at 60.degree. C. for a
further hour.
Production of the Particulate Graft Polymers
[0121] 2100 g of the emulsion produced in accordance with
specification (1) were mixed with 1150 g of water and 2.7 g of
potassium peroxodisulfate, and heated, with stirring, to 65.degree.
C. Once the reaction temperature had been reached, a mixture of 420
g of styrene (S) and 140 g of acrylonitrile (AN) was metered into
the mixture over the course of 3 hours. Once addition was complete,
the emulsion was kept at 65.degree. C. for a further 2 hours. The
graft polymer was precipitated from the emulsion by means of
calcium chloride solution at 95.degree. C., washed with water, and
dried in a stream of warm air.
[0122] Various graft copolymers A2 were produced with from 0.1 to
1.0% by weight of allyl methacrylate (AMA) as crosslinking agent.
The median particle size of the resultant graft copolymer A2 was
from 95-105 nm. Comparative examples CE1 and CE2 were also carried
out, using DCPA (as in DE 4006643 A1, p. 5, table) instead of
AMA.
TABLE-US-00001 TABLE 1 Monomer composition of graft copolymer A2
Graft base DCPA AMA Graft shell (% by DCPA (% by AMA (% by weight)
BA weight) (mol) weight) (mol) S AN CE1 99.0 1.0 0.176 -- -- 75 25
CE2 98.0 2.0 0.352 -- -- 75 25 A2-1 99.9 -- -- 0.1 0.029 75 25 A2-2
99.6 -- -- 0.4 0.116 75 25 A2-3 99.0 -- -- 1.0 0.290 75 25 Values
in mol are based on 9.0 kg of mixture
Component A3
Production of the Graft Base A31
[0123] The quantitative data below for BA and AMA are based in each
case on examples A3-1/A3-2/A3-3 as in table 2.
[0124] 16.31/16.26/16.21 parts of butyl acrylate (BA) and
0.02/0.08/0.15 parts of allyl methacrylate (AMA) are heated, with
stirring, to 60.degree. C. in 150 parts of water with addition of
one part of the sodium salt of a C.sub.12-C.sub.18-paraffinsulfonic
acid, 0.3 part of potassium persulfate, 0.3 part of sodium
hydrogencarbonate and 0.15 part of sodium phosphate. 10 minutes
after the start of the polymerization reaction, a mixture of
83.59/83.34/83.04 parts by weight of butyl acrylate and
0.08/0.32/0.60 part of allyl methacrylate were added within a
period of 3 hours. Once monomer addition had concluded, reaction of
the mixture was allowed to continue for a further hour. The solids
content of the resultant latex of the crosslinked butyl acrylate
polymer was 40% by weight. Median particle size (weight average)
was determined as 83/78/80 nm. The particle size distribution was
narrow (quotient Q=0.20).
Production of a Coarse-Particle Graft Copolymer A3
[0125] The following were added to an initial charge made of 1.5
parts of the latex A31 described above: after addition of 50 parts
of water and 0.1 part of potassium persulfate, over the course of 3
hours, at 60.degree. C., firstly a mixture made of
49.95/49.80/49.625 parts of butyl acrylate and 0.05/0.20/0.375 part
of allyl methacrylate, and secondly a solution of 0.5 part of the
sodium salt of a C.sub.12-C.sub.18-paraffinsulfonic acid in 25
parts of water. Once the feed had ended, polymerization was
continued for a further 2 hours. The solids content of the
resultant latex of the crosslinked butyl acrylate polymer was 40%
by weight. Median particle size (weight average of the latex) was
determined as 473/459/460 nm.
[0126] The particle size distribution was narrow (quotient
Q=0.15).
[0127] 150 parts of this latex were then mixed with 20 parts of
styrene and 60 parts of water, and heated, with stirring, to
65.degree. C. for 3 hours after addition of a further 0.03 part of
potassium persulfate and 0.05 part of lauroyl peroxide. The
dispersion obtained in the graft copolymerization reaction was then
polymerized for a further 4 hours with 20 parts of a mixture of
styrene and acrylonitrile in a ratio of 75:25. The reaction product
was then precipitated from the dispersion with a calcium chloride
solution at 95.degree. C., isolated, washed with water, and dried
in a stream of warm air. The degree of grafting of the graft
copolymer was determined as 40%; the median size of the latex
particles was 564/545/551 nm.
[0128] Various graft copolymers A3 were produced with from 0.1 to
0.75% by weight of allyl methacrylate as crosslinking agent (table
2).
[0129] Comparative examples CE3 and CE4 were also carried out with
DCPA (as in DE 4131729 A1, p. 6, table 1) instead of AMA.
TABLE-US-00002 TABLE 2 Monomer composition of graft copolymer A3
Graft base DCPA AMA Graft shell (% by DCPA (% by AMA (% by weight)
BA weight) (mol) weight) (mol) S AN CE3 99.0 1.0 0.176 -- -- 75 25
CE4 98.0 2.0 0.352 -- -- 75 25 A3-1 99.9 -- -- 0.1 0.029 75 25 A3-2
99.6 -- -- 0.4 0.116 75 25 A3-3 99.0 -- -- 0.75 0.217 75 25 Values
in mol are based on 9.0 kg of mixture
[0130] The mixtures A1 and A2 (table 3), A1 and A3 (table 4), and
A1, A2, and A3 (table 5) of the invention were produced by mixing
the respective components intimately in an extruder (ZSK 30
twin-screw extruder from Werner & Pfleiderer) at a temperature
of 230.degree. C. The respective ratios by weight were 70:30 in the
case of the mixture of A1 and A2, 70:30 in the case of the mixture
of A1 and A3, and 70:20:10 in the case of the mixture of A1, A2,
and A3.
[0131] The mixtures for the comparative examples using DCPA as
crosslinking agent component were likewise produced as described
above.
[0132] The resultant mixtures were tested for various mechanical
properties and for gloss. Tables 3 to 5 collate the results.
TABLE-US-00003 TABLE 3 Polymer mixture of A1 and A2 Crosslinking
agent Notched impact resistance Impact resistance Gloss (% by
weight) 23.degree. C. 0.degree. C. -30.degree. C. 23.degree. C.
0.degree. C. -30.degree. C. (60.degree.) CE1 2.0% (0.353 mol) 8.0
6.4 2.5 -- 248 100 93 DCPA CE2 1.0% (0.176 mol) 5.9 5.4 2.5 -- 240
119 88 DCPA 1 0.1% (0.029 mol) 3.5 3.2 2.2 129 165 83 88 AMA 2
0.16% (0.046 mol) 5.4 5.2 2.5 179 191 103 91 AMA 3 0.25% (0.0725
mol) 10.9 8.6 4.1 185 132 92 97 AMA 4 0.4% (0.116 mol) 12.0 10.4
4.6 233 199 139 97 AMA 5 0.5% (0.145 mol) 9.3 7.8 2.7 252 141 83 97
AMA 6 0.75% (0.217 mol) 9.1 6.6 2.1 177 133 67 96 AMA 7 1 .0%
(0.290 mol) 6.4 5.0 1.4 188 123 41 97 AMA Values in mol are based
on 9.0 kg of mixture CE1, CE2: comparative example using DCPA
instead of AMA
[0133] The polymer mixtures of the invention as in table 3, made of
A1 and A2, show that a considerable improvement of notched impact
resistance and of impact resistance at low temperatures, in
particular at -30.degree. C., is achieved by using a graft
copolymer A2 comprising allyl methacrylate (AMA) A212, even when
quantities of allyl methacrylate are small, i.e. from 0.1 to 0.5%
by weight, while gloss is actually increased.
[0134] Corresponding comparative examples CE1 and CE2 using DCPA as
crosslinking component of the graft copolymer already show a gloss
reduction when the proportion of DCPA is reduced from 2 to 1% by
weight. When quantities of DCPA used are from 0.2 to 0.8% by weight
the corresponding ASA product exhibits markedly matt surfaces,
which are not desired.
TABLE-US-00004 TABLE 4 Polymer mixture of A1 and A3 Crosslinking
agent Notched impact resistance Impact resistance Gloss (% by
weight) 23.degree. C. 0.degree. C. -30.degree. C. 23.degree. C.
0.degree. C. -30.degree. C. (60.degree.) CE3 2.0% (0.353 mol) 11.8
8.8 3.4 185 143 95 99 DCPA CE4 1.0% (0.176 mol) 11.8 8.7 3.4 198
147 120 98 DCPA 1 0.1% (0.029 mol) 12.8 11.5 5.0 182 130 90 99 AMA
2 0.16% (0.046 mol) 12.5 9.9 5.0 -- 171 124 99 AMA 3 0.2% (0.058
mol) 12.5 10.3 5.1 -- 154 114 99 AMA 4 0.4% (0.116 mol) 12.1 9.3
5.0 -- 218 132 100 AMA 5 0.5% (0.145 mol) 11.2 9.0 4.8 -- 228 118
99 AMA 6 0.75% (0.217 mol) 9.6 8.4 4.7 -- 178 126 99 AMA Values in
mol are based on 9.0 kg of mixture CE3, CE4: comparative
examples
[0135] The polymer mixtures of the invention as in table 4, made of
A1 and A3, show that a considerable improvement of notched impact
resistance and impact resistance at low temperatures, for example
at -30.degree. C., is achieved by using a coarse-particle graft
copolymer A3 which comprises only small quantities of allyl
methacrylate (AMA) A312 (from 0.1 to 0.5% by weight), while gloss
is maintained. The mechanical properties of the polymer mixtures of
the invention are actually mostly better than when markedly greater
quantities of DCPA are used, while gloss is maintained.
[0136] These results were not expected and are surprising to the
person skilled in the art, since it is general knowledge in the art
that increasing content of crosslinking agent achieves increased or
improved gloss (cf., for example, U.S. Pat. No. 6,476,128). In
contrast to this, a corresponding ASA product exhibits markedly
matt surfaces when DCPA is used at a concentration in the range
below 1% by weight.
TABLE-US-00005 TABLE 5 Polymer mixture of A1, A2 and A3 Notched
impact Impact resistance Ak resistance Modulus of Penetration
[kJ/m.sup.2] An [kJ/m.sup.2] elasticity MVR [kJ/m.sup.2] A2, A3
23.degree. C. 0.degree. C. -30.degree. C. 23.degree. C. 0.degree.
C. -30.degree. C. [MPa] (220/10) 23.degree. C. -20.degree. C. CE1
2.0% by weight 8.9 7.4 2.7 -- 144 93 2434 7.4 28.3 6.6 (0.353 mol)
DCPA 2 0.16% by weight 10.9 8.2 3.6 -- 153 110 2455 8.0 39.8 12.8
(0.046 mol) AMA 3 0.4% by weight 10.5 6.5 2.0 -- 159 105 -- 8.1 --
-- (0.115 mol) AMA 4 A2: 0.4% by weight 12.2 7.0 2.1 -- 181 101 --
8.3 -- -- (0.115 mol) AMA A3: 0.2% by weight (0.0575 mol) AMA
Values in mol are based on 9.0 kg of mixture
[0137] The stated quantities of crosslinking agent were used
mutually independently respectively for component A2 and A3. The
comparative example was carried out correspondingly, but using 2%
by weight of DCPA instead of AMA.
[0138] The polymer mixtures of the invention as in table 5, made of
A1, A2, and A3, show that a considerable improvement of notched
impact resistance and impact resistance at temperatures including
low temperatures is achieved by using the graft copolymers A2 and
A3 respectively comprising only small quantities of allyl
methacrylate.
[0139] Corresponding comparative examples as in the prior art using
DCPA as crosslinking component lead to markedly poorer results,
although quantities of DCPA used were greater, namely respectively
2% by weight for the coarse- and fine-particle graft copolymer.
[0140] From the polymer mixtures described it is possible, by using
familiar methods, to produce moldings which are in particular
suitable for applications including outdoor applications and which
have an improved toughness/stiffness ratio and good optical
properties.
* * * * *