U.S. patent application number 12/490507 was filed with the patent office on 2010-08-19 for method of preparing ethylene polymers by controlled high pressure polymerization.
This patent application is currently assigned to CIBA CORPORATION. Invention is credited to FRANK FREIDEL, GERHARD LUFT, RUDOLF PFAENDNER, MICHAEL ROTH.
Application Number | 20100210800 12/490507 |
Document ID | / |
Family ID | 42562881 |
Filed Date | 2010-08-19 |
United States Patent
Application |
20100210800 |
Kind Code |
A1 |
ROTH; MICHAEL ; et
al. |
August 19, 2010 |
METHOD OF PREPARING ETHYLENE POLYMERS BY CONTROLLED HIGH PRESSURE
POLYMERIZATION
Abstract
The present invention relates to a method for the radical
polymerization or copolymerization of ethylene at high pressures
using a hydroxylamine ester as radical initiator. The hydroxylamine
esters according to the invention are suitable initiators for the
high pressure polymerization of ethylene leading to high molecular
weight polyethylenes with narrow molecular weight distributions
(Poyldispersity Index PD=1.2-4.5).
Inventors: |
ROTH; MICHAEL; (LAUTERTAL,
DE) ; PFAENDNER; RUDOLF; (RIMBACH, DE) ; LUFT;
GERHARD; (MUHLTAL, DE) ; FREIDEL; FRANK;
(ERBACH, DE) |
Correspondence
Address: |
BASF Performance Products LLC;Patent Department
540 White Plains Road, P.O. Box 2005
Tarrytown
NY
10591
US
|
Assignee: |
CIBA CORPORATION
TARRYTOWN
NY
|
Family ID: |
42562881 |
Appl. No.: |
12/490507 |
Filed: |
June 24, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10592726 |
Sep 14, 2006 |
|
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PCT/EP2005/051130 |
Mar 14, 2005 |
|
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12490507 |
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Current U.S.
Class: |
526/204 ;
526/220 |
Current CPC
Class: |
C08F 110/02 20130101;
C08F 10/00 20130101; C08F 110/02 20130101; C08F 2/00 20130101; C08F
4/32 20130101; C08F 2500/12 20130101; C08F 4/00 20130101; C08F
110/02 20130101; C08F 2500/10 20130101; C08F 110/02 20130101; C08F
10/00 20130101 |
Class at
Publication: |
526/204 ;
526/220 |
International
Class: |
C08F 2/38 20060101
C08F002/38 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2004 |
EP |
04101214.7 |
Claims
1. A method for the polymerization or copolymerization of ethylene,
which method comprises polymerizing or copolymerizing ethylene at
an operating pressure of from 500 to 3500 bar, at a polymerization
temperature between 100.degree. and 400.degree. C. in a suitable
high pressure reactor, operating continuously or batch wise and in
the presence of a radical polymerization initiator, wherein the
polydispersity, PD, of the resulting polyethylene is between 1.2
and 4.5, as measured by gel permeation chromatography, and where
the weight average molecular weight is from 284,000 to 547,000,
characterized in that the radical polymerization initiator is a
hydroxylamine ester containing a structural element of formula (I)
or (I') ##STR00068## wherein X is hydrogen, C.sub.1-C.sub.36alkyl,
C.sub.1-C.sub.36alkyl which is substituted by halogen,
C.sub.6-C.sub.12cycloalkyl, C.sub.7-C.sub.12bicyclo- or
tricycloalkyl, C.sub.2-C.sub.36alkenyl, C.sub.2-C.sub.18alkynyl,
C.sub.6-C.sub.10aryl, --O--C.sub.1-C.sub.18alkyl,
--O--C.sub.6-C.sub.10aryl, --NH--C.sub.1-C.sub.18alkyl,
--NH--C.sub.6-C.sub.10aryl or --N(C.sub.1-C.sub.6alkyl).sub.2; and
X' is a direct bond or is C.sub.1-C.sub.36alkylene,
C.sub.2-C.sub.36alkenylene, C.sub.2-C.sub.36alkynylene,
--(C.sub.1-C.sub.6alkylene)-phenyl-(C.sub.1-C.sub.6alkylene) or a
group ##STR00069## where * indicates the bond to which the carbonyl
groups are attached.
2. A method according to claim 1 wherein the operating pressure is
of from 1000 to 3000 bar.
3. A method according to claim 1 wherein the polymerization
temperature is of from 140.degree. to 300.degree. C.
4. A method according to claim 1 wherein the hydroxylamine ester is
present in an amount of from 5 to 500 parts per million based on
the weight of the total reaction mixture.
5. A method according to claim 1, wherein the hydroxylamine ester
is a compound of formula (Ia) or (Ia') ##STR00070## wherein X is
hydrogen, C.sub.1-C.sub.36alkyl, C.sub.1-C.sub.36alkyl which is
substituted by halogen, C.sub.6-C.sub.12cycloalkyl,
C.sub.7-C.sub.12bicyclo- or tricycloalkyl, C.sub.2-C.sub.36alkenyl,
C.sub.2-C.sub.18alkynyl, C.sub.6-C.sub.10aryl,
--O--C.sub.1-C.sub.18alkyl, --O--C.sub.6-C.sub.10aryl,
--NH--C.sub.1-C.sub.18alkyl, --NH--C.sub.6-C.sub.10aryl or
--N(C.sub.1-C.sub.6alkyl).sub.2; X' is a direct bond or
C.sub.1-C.sub.36alkylene, C.sub.2-C.sub.36alkenylene,
C.sub.2-C.sub.36alkynylene, phenylene,
--(C.sub.1-C.sub.6alkylene)-phenyl-(C.sub.1-C.sub.6alkylene) or a
group ##STR00071## R.sub.20, R'.sub.20, R.sub.30 and R'.sub.30 are
each independently of the others unsubstituted, halo-, CN--,
NO.sub.2-- or --COOR.sub.40-substituted or O-- or NR.sub.40--
interrupted C.sub.1-C.sub.18alkyl, C.sub.2-C.sub.18alkenyl or
C.sub.2-C.sub.18alkynyl; R.sub.40 is hydrogen, phenyl or
C.sub.1-C.sub.18alkyl; or R.sub.20 and R.sub.30 and/or R'.sub.20
and R'.sub.30, together with the nitrogen atom to which they are
bonded, form a 5- or 6-membered ring which may be interrupted by a
nitrogen or oxygen atom and which may be substituted one or more
times by C.sub.1-C.sub.6alkyl groups and carboxyl groups.
6. A method according to claim 5, where in the compound of formula
(Ia), R.sub.20 and R.sub.30, together with the nitrogen atom to
which they are bonded, form a piperidine ring which is substituted
in the 2,2- and 6,6-positions by C.sub.1-C.sub.4alkyl groups and in
the 4-position has an ether, amine, amide, urethane, ester or ketal
group.
7. A method according to claim 5, where the hydroxylamine ester is
a compound of formula (A), (B), (C) or (O) ##STR00072## wherein
G.sub.1, G.sub.2, G.sub.3 and G.sub.4 are each independently of the
others alkyl having from 1 to 4 carbon atoms; G.sub.5 and G.sub.6
are each independently of the other hydrogen or
C.sub.1-C.sub.4alkyl; m is a number 1-2; R, when m is 1, is
hydrogen, uninterrupted C.sub.1-C.sub.18alkyl or
C.sub.2-C.sub.18alkyl interrupted by one or more oxygen atoms, or
is cyanoethyl, benzoyl, glycidyl, a monovalent radical of an
aliphatic carboxylic acid having from 2 to 18 carbon atoms, of a
cycloaliphatic carboxylic acid having from 7 to 15 carbon atoms or
of an .alpha.,.beta.-unsaturated carboxylic acid having from 3 to 5
carbon atoms or of an aromatic carboxylic acid containing from 7 to
15 carbon atoms, it being possible for each carboxylic acid to be
substituted in the aliphatic, cycloaliphatic or aromatic unit by
from 1 to 3 groups --COOZ.sub.12 wherein Z.sub.12 is hydrogen,
C.sub.1-C.sub.20alkyl, C.sub.3-C.sub.12alkenyl,
C.sub.5-C.sub.7cycloalkyl, phenyl or benzyl; or R is a monovalent
radical of a carbamic acid or phosphorus-containing acid or is a
monovalent silyl radical; R, when m is 2, is
C.sub.2-C.sub.12alkylene, C.sub.4-C.sub.12alkenylene, xylylene, a
bivalent radical of an aliphatic dicarboxylic acid having from 2 to
36 carbon atoms or of a cycloaliphatic or aromatic dicarboxylic
acid having from 8 to 14 carbon atoms or of an aliphatic,
cycloaliphatic or aromatic dicarbamic acid having from 8 to 14
carbon atoms, it being possible for each dicarboxylic acid to be
substituted in the aliphatic, cycloaliphatic or aromatic unit by
one or two groups --COOZ.sub.12; or R is a bivalent radical of a
phosphorus-containing acid or a bivalent silyl radical; p is 1,
R.sub.1 is C.sub.1-C.sub.12alkyl, C.sub.5-C.sub.7cycloalkyl,
C.sub.7-C.sub.8aralkyl, C.sub.2-C.sub.18alkanoyl,
C.sub.3-C.sub.5alkenoyl or benzoyl; R.sub.2 is
C.sub.1-C.sub.18alkyl, C.sub.5-C.sub.7cycloalkyl or
C.sub.2-C.sub.8alkenyl, each unsubstituted or substituted by a
cyano, carbonyl or carbamide group, or is glycidyl, a group of
formula --CH.sub.2CH(OH)--Z or of formula --CO--Z or --CONH--Z,
wherein Z is hydrogen, methyl or phenyl; n is a number 1 or 2; when
n is 1, R.sub.3 is C.sub.2-C.sub.8alkylene or hydroxyalkylene or
C.sub.4-C.sub.36acyloxyalkylene; or, when n is 2, R.sub.3 is
(--CH.sub.2).sub.2C(CH.sub.2--).sub.2 and X is as defined in claim
5.
8. A method according to claim 5, wherein the substituent X is
selected from the group consisting of C.sub.1-C.sub.36alkyl,
C.sub.2-C.sub.19alkenyl and C.sub.6-C.sub.10aryl.
9. A method according to claim 1 wherein the hydroxylamine ester is
of formula (C') ##STR00073## wherein X is hydrogen or
C.sub.1-C.sub.18alkyl and R.sub.100 is C.sub.4-C.sub.24alkyl.
10. A method according to claim 1, wherein the hydroxylamine ester
is an oligomer or polymer obtained by reacting a dicarboxylic acid
with a compound of formula A1 or B1 or by reacting a diisocyanate
with a compound of formula A1, ##STR00074## B1 wherein G.sub.1,
G.sub.2, G.sub.3 and G.sub.4 are each independently of the others
C.sub.1-C.sub.4alkyl, or G.sub.1 and G.sub.2 together and G.sub.3
and G.sub.4 together, or G.sub.1 and G.sub.2 together or G.sub.3
and G.sub.4 together are pentamethylene; G.sub.5 and G.sub.6 are
each independently of the other hydrogen or C.sub.1-C.sub.4alkyl;
and R.sub.1 is C.sub.1-C.sub.12alkyl, C.sub.5-C.sub.7cycloalkyl,
C.sub.7-C.sub.8aralkyl, C.sub.2-C.sub.18alkanoyl,
C.sub.3-C.sub.5alkenoyl or benzoyl.
11. A method according to claim 1 wherein an additional organic
radical initiator is added.
12. A method according to claim 11 wherein the organic radical
initiator is selected from the group consisting of
isobutyryl-peroxide, isopropylperoxy-dicarbonate,
di-n-butylperoxy-dicarbonate, di-sec-butylperoxy-dicarbonate,
dicyclohexylperoxy-dicarbonate, di(2-ethylhexyl)peroxy-dicarbonate,
t-butyl-perneodecanoate, t-butyl-perpivalate,
bis(3,5,5-trimethyl-hexanoyl)peroxide, didecanoyl-peroxide,
dilauroyl-peroxide, t-butyl-perisobutyrate,
t-butyl-per2-ethylhexanoate, t-butyl-peracetate,
t-butyl-per-3,5,5-trimethylhexanoate, t-butyl-perbenzoate,
di-t-butyl-peroxide, t-butyl-hydroperoxide and
di-t-amylperoxide.
13. A method according to claim 1 wherein additionally a chain
transfer agent is added.
14. A method according to claim 13 wherein the chain transfer agent
is selected from the group consisting of ketones, aldehydes,
C.sub.3-C.sub.20alkanes, C.sub.3-C.sub.20alkenes, mercaptanes and
disulfides.
15. A method according to claim 1 wherein a comonomer is present
which is a monomer containing a vinyl group, an allyl group, a
vinylidene group, a diene group or an olefinic group and which is
other than ethylene.
16. A method according to claim 15 wherein a comonomer is present
which is selected from the group consisting of methylacrylate,
ethylacrylate, n-butylacrylate, vinylacetate, styrene,
.alpha.-methylstyrene and methylmethacrylate.
17. An ethylene polymer or copolymer obtained by the method of
claim 1.
Description
[0001] This application is a continuation in part of U.S.
application Ser. No. 10/592,726, which is a national stage of
PCT/EP 2005/051130, filed Mar. 14, 2005, the contents of which are
incorporated by reference.
[0002] The present invention relates to a method for the radical
polymerization or copolymerization of ethylene at high pressures
using a hydroxylamine ester as radical initiator. A further aspect
is the use of specific hydroxylamine esters as radical initiators
for the (co)polymerization of ethylene.
[0003] The manufacture of ethylene polymers (PE) having varying
structures and characteristics is well known in the art. There are
different polymerization techniques, e.g. high pressure radically
initiated polymerization, leading to low density polyethylene
(LDPE), coordination polymerization with Ziegler-Natta-, chromium-,
aluminium-catalysts, leading to high density polyethylene (HDPE) or
polymerization with metallocene catalysts, which affect the
molecular structure, such as degree of branching, molecular weight
and molecular weight distribution as measured by the polydisperity
as well as the physical properties, such as density, crystallinity,
melting point and the processing behaviour.
[0004] The density of low density polyethylene (LDPE) may vary from
0.910-0.955 g/cm.sup.3, whereas commercial products usually have
densities of 0.916-0.935. The degree of crystallinity of such
products varies between 45-55% with melting points between
105-115.degree. C. LDPE has a random branching structure and
contains besides alkyl substituents (short chain branches coming
from "back biting" reactions during polymerization) also long chain
branches formed by molecular rearrangements of the PE backbone
during chain growth.
[0005] The processes for the polymerization of ethylene at high
temperatures and high pressures by means of initiating free
radicals have been known for a long time. Ethylene polymers are
obtained by homopolymerizing ethylene or by copolymerizing it with
at least one comonomer in a polymerization system, which operates
continuously under pressures of 500-3500 bar (50-350 Mpa) and at
temperatures of 120-400.degree. C. The polymerization is carried
out in continuous tubular reactors or stirred autoclaves in the
presence of initiators and optionally of transfer agents (e.g.
n-alkanes, ketones, aldehydes, thiols), which adjust the molecular
weights of the resulting polymers, however, on the expense of
broadening the molecular weight distribution. Most commonly
peroxides or hydroperoxides are used as initiators. The polymers
are subsequently separated from the volatile substances after their
removal from the reactor in separators. A general description of
manufacturing processes, properties and use of ethylene polymers is
for example given in Ullmann's Encyclopedia of Industrial
Chemistry, Vol. A21, Editors: B. Elvers, S. Hawkins, G. Schulz, 5th
completely rev. ed. 1992, VCH Verlags GmbH, Weinheim, pp.
487-517.
[0006] Molecular structure and physical properties of polyethylenes
are not only influenced by manufacturing conditions but also by the
type of initiator used. The rate of decomposition, i.e. its
half-life time (as a rule .about.0.1-1 sec under a given
temperature profile), has direct influence on the polymerization
rate and, therefore, on the heat of polymerization. The initiator
consumption can be considered as a measure for initiator efficiency
which influences not only the molecular weight of the resulting
polymer but also affects the concentration of end groups (initiator
fragments) and decomposition products. Common values for peroxides
are 10-1000 g/t polymer.
[0007] Handling and safety issues are as well important aspects of
polymerization processes, where large amounts of peroxides are
used. Not only storage and metering of peroxide containing
solutions have to be kept under observation but also process
technology and process control have to be adapted to the safety
requirements.
[0008] Surprisingly, it has now been found that hydroxylamine
esters according to the invention are suitable initiators for the
high pressure ethylene polymerization leading to high molecular
weight polyethylenes with narrow molecular weight distributions
(Poyldispersity Index PD=2-4.5). Additionally the PD of
polyethylene produced according to the instant invention becomes
even narrower, when the polymerization temperature is lowered
(T<180.degree. C.).
[0009] Prior art peroxides show an inverse behavior. The resulting
polyethylenes generally have much broader PDs (PD=7-12) and
narrower distributions can only be achieved with increasing
temperatures (T>250.degree. C.). This is for example described
by G. Luft, H. Seidl in Angew. Macromol. Chem. 1985, 129, pp
61-70.
[0010] One possibility to achieve polyethylenes with narrow PD, in
high pressure polymerization, is by the combined use of free
radical generators and nitroxyl radicals as, for example, disclosed
in EP 0 811 590 and U.S. Pat. No. 5,449,724. However, this process
needs careful adjustment of the ratio of radical generator and
nitroxyl radical according to different process conditions.
Furthermore the nitroxyl radical is slowing down the polymerization
rate, making high process temperatures necessary. However, high
manufacturing temperatures are not desirable due to energy
economics and side reactions of the polymerization process.
[0011] U.S. Pat. No. 6,479,608 discloses heterocyclic alkoxyamines,
which are useful initiator/regulator compounds for the controlled
polymerization of a variety of ethylenically unsaturated monomers.
These compounds split into a regulating NO radical and an
initiating carbon centered radical.
[0012] The instant invention provides a different solution for the
preparation of polyethylenes with even narrower polydispersities by
using solely the hydroxylamine esters of the instant invention as
radical initiators. These compounds allow an excellent control of
the poly-ethylene polymerization process without the need to adjust
the ratio of different molecules. Furthermore the process can be
carried out advantageously at comparatively low temperatures.
Moreover, as the method of the present invention can be performed
at low temperatures, copolymers of ethylene with e.g. styrene,
vinylacetate and narrow molecular weight distribution are
accessible. These copolymers are not accessible at high
temperatures due to the ceiling temperature of these monomers,
which results otherwise in a polymerization/depolymerization
equilibrium with only low molecular weight products unsuitable for
industrial applications.
[0013] Hydroxylamine esters do not form any nitroxyl radicals
during decomposition but selectively cleave into aminyl and carbon
centered radicals, which surprisingly are able to initiate ethylene
polymerization under high pressure. The result is a polyethylene
with low polydispersity.
[0014] One aspect of the invention is a method for the
polymerization or copolymerization of ethylene at an operating
pressure of from 500 to 3500 bar, at a polymerization temperature
between 100.degree. and 400.degree. C. in a suitable high pressure
reactor, operating continuously or batch wise
by the use of a radical polymerization initiator, characterized in
that the radical polymerization initiator is a hydroxylamine ester
containing a structural element of formula (I) or (I')
##STR00001##
wherein X is hydrogen, C.sub.1-C.sub.36alkyl, C.sub.1-C.sub.36alkyl
which is substituted by halogen, C.sub.5-C.sub.12cycloalkyl,
C.sub.7-C.sub.12bicyclo- or tricycloalkyl, C.sub.2-C.sub.36alkenyl,
C.sub.2-C.sub.18alkynyl, C.sub.6-C.sub.10aryl,
--O--C.sub.1-C.sub.18alkyl, --O--C.sub.6-C.sub.10aryl,
--NH--C.sub.1-C.sub.18alkyl, --NH--C.sub.6-C.sub.10aryl,
--N(C.sub.1-C.sub.6alkyl).sub.2; X' is a direct bond or
C.sub.1-C.sub.36alkylene, C.sub.2-C.sub.36alkenylene,
C.sub.2-C.sub.36alkynylene,
--(C.sub.1-C.sub.6alkylene)-phenyl-(C.sub.1-C.sub.6alkylene) or a
group
##STR00002##
and * indicates the bond to which the carbonyl groups are
attached.
[0015] Preferably the operating pressure is of from 1000 to 3000
bar.
[0016] Preferably the polymerization temperature is of from
140.degree. to 300.degree. C.
[0017] In a preferred method the polydispersity, PD, of the
resulting polyethylene is between 1.2 and 4.5, in particular
between 1.2 and 3.5.
[0018] The hydroxylamine ester is, for example, used in an amount
of from 5 to 500 parts per million, preferably of from 5 to 300
parts per million and more preferably of from 10 to 200 parts per
million based on the weight of the total reaction mixture.
[0019] Suitable reactors for high pressure ethylene polymerization
using peroxides are well known and for example described by H.
Seidl, G. Luft, J. Macromol. Sci.-Chem. 1981, A15(1), pp. 1-33. The
process is typically a continuous process using, for example, a
continuous tubular reactor or a stirred autoclave reactor. A
detailed flow sheet is for example given in U.S. Pat. No.
6,562,915
[0020] The hydroxylamine ester is preferably a compound of formula
(Ia) or (I' a)
##STR00003##
wherein X is hydrogen, C.sub.1-C.sub.36alkyl, C.sub.1-C.sub.36alkyl
which is substituted by halogen, C.sub.6-C.sub.12cycloalkyl,
C.sub.7-C.sub.12bicyclo- or tricycloalkyl, C.sub.2-C.sub.36alkenyl,
C.sub.2-C.sub.18alkynyl, C.sub.6-C.sub.10aryl,
--O--C.sub.1-C.sub.18alkyl, --O--C.sub.6-C.sub.10aryl,
--NH--C.sub.1-C.sub.18alkyl, --NH--C.sub.6-C.sub.10aryl,
--N(C.sub.1-C.sub.6alkyl).sub.2; X' is a direct bond or
C.sub.1-C.sub.36alkylene, C.sub.2-C.sub.36alkenylene,
C.sub.2-C.sub.36alkynylene, phenylene,
--(C.sub.1-C.sub.6alkylene)-phenyl-(C.sub.1-C.sub.6alkylene) or a
group
##STR00004##
R.sub.20, R'.sub.20, R.sub.30 and R'.sub.30 are each independently
of the others unsubstituted, halo-, CN--, NO.sub.2-- or
--COOR.sub.40-substituted or O-- or NR.sub.40-interrupted
C.sub.1-C.sub.18alkyl, C.sub.2-C.sub.18alkenyl,
C.sub.2-C.sub.18alkynyl; R.sub.40 is hydrogen, phenyl or
C.sub.1-C.sub.18alkyl; or R.sub.20 and R.sub.30 and/or R'.sub.20
and R'.sub.30, together with the nitrogen atom to which they are
bonded, form a 5- or 6-membered ring which may be interrupted by a
nitrogen or oxygen atom and which may be substituted one or more
times by C.sub.1-C.sub.6alkyl groups and carboxyl groups.
[0021] Any substituents that are C.sub.1-C.sub.12alkyl are, for
example, methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl,
n-hexyl, n-octyl, 2-ethyl-hexyl, n-nonyl, n-decyl, n-undecyl or
n-dodecyl. C.sub.1-C.sub.18Alkyl may be, for example, the groups
mentioned above and also, in addition, for example, n-tridecyl,
n-tetradecyl, n-hexadecyl and n-octadecyl.
[0022] C.sub.2-C.sub.36alkenyl may be, for example, 1-propenyl,
allyl, methallyl, 2-butenyl, 2-pentenyl, 2-hexenyl, 2-octenyl or
4-tert-butyl-2-butenyl.
[0023] C.sub.2-C.sub.36alkinyl may be, for example, propinyl,
butinyl, hexinyl or dodecinyl
[0024] C.sub.6-C.sub.12Cycloalkyl is, for example, cyclopentyl,
cyclohexyl or cycloheptyl.
[0025] Any substituents that are C.sub.2-C.sub.12alkylene are, for
example, ethylene, propylene, 2,2-dimethyl-propylene,
tetramethylene, hexamethylene, octamethylene, decamethylene or
dodecamethylene.
[0026] Any substituents that are aryl are for example phenyl or
naphthyl.
[0027] Any substituents that are C.sub.6-C.sub.15arylene are, for
example, o-, m- or p-phenylene, 1,4-naphthylene or
4,4'-diphenylene.
[0028] Halogen is F, Cl, Br and I. Alkyl substituted by halogen is
for example trifluormethyl.
[0029] The hydroxylamine esters are known and for example described
in WO 02/092653.
[0030] Preparation of hydroxylamine esters that may advantageously
be used in the above-mentioned method are described, for example,
in U.S. Pat. Nos. 4,590,231, 5,300,647, 4,831,134, 5,204,473,
5,004,770, 5,096,950, 5,021,478, 5,118,736, 5,021,480, 5,015,683,
5,021,481, 5,019,613, 5,021,486, 5,021,483, 5,145,893, 5,286,865,
5,359,069, 4,983,737, 5,047,489, 5,077,340, 5,021,577, 5,189,086,
5,015,682, 5,015,678, 5,051,511, 5,140,081, 5,204,422, 5,026,750,
5,185,448, 5,180,829, 5,262,538, 5,371,125, 5,216,156 and
5,300,544.
[0031] Further hydroxylamine esters and the preparation thereof are
described in WO 01/90113.
[0032] Preferred hydroxylamine esters are of formula (Ia) wherein
R.sub.20 and R.sub.30, together with the nitrogen atom to which
they are bonded, form a piperidine ring which is substituted in the
2,2- and 6,6-positions by C.sub.1-C.sub.4alkyl groups and in the
4-position has an ether, amine, amide, urethane, ester or ketal
group. Special preference is given to cyclic ketals.
[0033] For example the hydroxylamine esters are of formula (A),
(B), (C) or (O)
##STR00005##
wherein G.sub.1, G.sub.2, G.sub.3 and G.sub.4 are each
independently of the others alkyl having from 1 to 4 carbon atoms;
G.sub.5 and G.sub.6 are each independently of the other hydrogen or
C.sub.1-C.sub.4alkyl; m is a number 1-2; R, when m is 1, is
hydrogen, uninterrupted C.sub.1-C.sub.18alkyl or
C.sub.2-C.sub.18alkyl interrupted by one or more oxygen atoms, or
is cyanoethyl, benzoyl, glycidyl, a monovalent radical of an
aliphatic carboxylic acid having from 2 to 18 carbon atoms, of a
cycloaliphatic carboxylic acid having from 7 to 15 carbon atoms or
of an .alpha.,.beta.-unsaturated carboxylic acid having from 3 to 5
carbon atoms or of an aromatic carboxylic acid containing from 7 to
15 carbon atoms, it being possible for each carboxylic acid to be
substituted in the aliphatic, cycloaliphatic or aromatic unit by
from 1 to 3 groups --COOZ.sub.12 wherein Z.sub.12 is hydrogen,
C.sub.1-C.sub.20alkyl, C.sub.3-C.sub.12alkenyl,
C.sub.5-C.sub.7cycloalkyl, phenyl or benzyl; or R is a monovalent
radical of a carbamic acid or phosphorus-containing acid or is a
monovalent silyl radical; R, when m is 2, is
C.sub.2-C.sub.12alkylene, C.sub.4-C.sub.12alkenylene, xylylene, a
bivalent radical of an aliphatic dicarboxylic acid having from 2 to
36 carbon atoms or of a cycloaliphatic or aromatic dicarboxylic
acid having from 8 to 14 carbon atoms or of an aliphatic,
cycloaliphatic or aromatic dicarbamic acid having from 8 to 14
carbon atoms, it being possible for each dicarboxylic acid to be
substituted in the aliphatic, cycloaliphatic or aromatic unit by
one or two groups --COOZ.sub.12; or R is a bivalent radical of a
phosphorus-containing acid or a bivalent silyl radical; p is 1,
R.sub.1 is C.sub.1-C.sub.12alkyl, C.sub.5-C.sub.7cycloalkyl,
C.sub.7-C.sub.8aralkyl, C.sub.2-C.sub.18alkanoyl,
C.sub.3-C.sub.5alkenoyl or benzoyl; R.sub.2 is
C.sub.1-C.sub.18alkyl, C.sub.5-C.sub.7cycloalkyl,
C.sub.2-C.sub.8alkenyl, each unsubstituted or substituted by a
cyano, carbonyl or carbamide group, or is glycidyl, a group of
formula --CH.sub.2CH(OH)--Z or of formula --CO--Z or --CONH--Z,
wherein Z is hydrogen, methyl or phenyl; n is a number 1 or 2; when
n is 1, R.sub.3 is C.sub.2-C.sub.8alkylene or hydroxyalkylene or
C.sub.4-C.sub.36acyloxyalkylene; or, when n is 2,
R.sub.3 is (--CH.sub.2).sub.2C(CH.sub.2--).sub.2 and
[0034] X is as defined above.
[0035] A likewise preferred group consists of hydroxylamines
wherein G.sub.1 and G.sub.2 are ethyl and G.sub.3 and G.sub.4 are
methyl, or G.sub.1 and G.sub.3 are ethyl and G.sub.2 and G.sub.4
are methyl; and G.sub.5 and G.sub.6 are each independently of the
other hydrogen or methyl.
[0036] C.sub.4-C.sub.36Acyloxyalkylene is, for example,
2-ethyl-2-acetoxymethylpropylene. R.sub.3 is especially a group of
the formula
##STR00006##
[0037] The other substituents have the definitions, including the
preferred meanings, given above.
[0038] Preferably the substituent X is selected from the group
consisting of C.sub.1-C.sub.36alkyl, C.sub.2-C.sub.19alkenyl and
C.sub.6-C.sub.10aryl.
[0039] Special preference is given to a hydroxylamine ester of
formula (C')
##STR00007##
wherein X is hydrogen or C.sub.1-C.sub.18alkyl and R.sub.100 is
C.sub.4-C.sub.24alkyl Further suitable hydroxylamine esters are
oligomers or polymers obtained by reacting a dicarboxylic acid with
a compound of formula A1 or B1 or by reacting a diisocyanate with a
compound of formula A1
##STR00008##
wherein G.sub.1, G.sub.2, G.sub.3 and G.sub.4 are each
independently of the others C.sub.1-C.sub.4alkyl, or G.sub.1 and
G.sub.2 together and G.sub.3 and G.sub.4 together, or G.sub.1 and
G.sub.2 together or G.sub.3 and G.sub.4 together are
pentamethylene; G.sub.5 and G.sub.6 are each independently of the
other hydrogen or C.sub.1-C.sub.4alkyl; and R.sub.1 is
C.sub.1-C.sub.12alkyl, C.sub.5-C.sub.7cycloalkyl,
C.sub.7-C.sub.5aralkyl, C.sub.2-C.sub.18alkanoyl,
C.sub.3-C.sub.5alkenoyl or benzoyl.
[0040] The compounds of formula A1 may be reacted to form
polyesters. The polyesters may be homo- or co-polyesters that are
derived from aliphatic, cycloaliphatic or aromatic dicarboxylic
acids and diols and a compound of formula A1.
[0041] The aliphatic dicarboxylic acids may contain from 2 to 40
carbon atoms, the cycloaliphatic dicarboxylic acids from 6 to 10
carbon atoms, the aromatic dicarboxylic acids from 8 to 14 carbon
atoms, the aliphatic hydroxycarboxylic acids from 2 to 12 carbon
atoms and the aromatic and cycloaliphatic hydroxycarboxylic acids
from 7 to 14 carbon atoms.
[0042] It is also possible for the polyesters, in small amounts,
for example from 0.1 to 3 mol %, based on the dicarboxylic acids
present, to be branched by means of more than difunctional monomers
(for example, pentaerythritol, trimellitic acid,
1,3,5-tri(hydroxyphenyl)benzene, 2,4-dihydroxybenzoic acid or
2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane).
[0043] Suitable dicarboxylic acids are linear and branched
saturated aliphatic dicarboxylic acids, aromatic dicarboxylic acids
and cycloaliphatic dicarboxylic acids.
[0044] Suitable aliphatic dicarboxylic acids are those having from
2 to 40 carbon atoms, for example oxalic acid, malonic acid,
dimethylmalonic acid, succinic acid, pimelic acid, adipic acid,
trimethyladipic acid, sebacic acid, azelaic acid and dimeric acids
(dimerisation products of unsaturated aliphatic carboxylic acids
such as oleic acid), alkylated malonic and succinic acids such as
octadecylsuccinic acid.
[0045] Suitable cycloaliphatic dicarboxylic acids are:
1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic
acid, 1,3- and 1,4-cyclohexanedicarboxylic acid, 1,3- and
1,4-(dicarboxylmethyl)cyclohexane and 4,4'-dicyclohexyldicarboxylic
acid.
[0046] Suitable aromatic dicarboxylic acids are: especially
terephthalic acid, isophthalic acid, ophthalic acid, and 1,3-,
1,4-, 2,6- or 2,7-naphthalenedicarboxylic acid,
4,4'-diphenyldicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic
acid, 4,4'-benzophenonedicarboxylic acid,
1,1,3-trimethyl-5-carboxyl-3-(p-carboxylphenyl)-indan,
4,4'-diphenyl ether dicarboxylic acid,
bis-p-(carboxylphenyl)-methane or
bis-p-(carboxylphenyl)-ethane.
[0047] Preference is given to the aromatic dicarboxylic acids and,
amongst those, especially terephthalic acid, isophthalic acid and
2,6-naphthalenedicarboxylic acid.
[0048] Further suitable dicarboxylic acids are those that contain
--CO--NH-- groups; they are described in DE-A 2 414 349.
Dicarboxylic acids that contain N-heterocyclic rings are also
suitable, for example those that are derived from
carboxylalkylated, carboxylphenylated or carboxybenzylated
monoamine-s-triazinedicarboxylic acids (cf. DE-A 2 121 184 and 2
533 675), mono- or bis-hydantoins, optionally halogenated
benzimidazoles or parabanic acid. The carboxyalkyl groups therein
may contain from 3 to 20 carbon atoms.
[0049] When additional diols are used, suitable aliphatic diols are
the linear and branched aliphatic glycols, especially those having
from 2 to 12, more especially from 2 to 6, carbon atoms in the
molecule, for example: ethylene glycol, 1,2- and 1,3-propylene
glycol, 1,2-, 1,3-, 2,3- or 1,4-butanediol, pentyl glycol,
neopentyl glycol, 1,6-hexanediol and 1,12-dodecanediol. A suitable
cycloaliphatic diol is, for example, 1,4-dihydroxycyclohexane.
Further suitable aliphatic diols are, for example,
1,4-bis(hydroxymethyl)cyclohexane, aromatic-aliphatic diols such as
p-xylylene glycol or 2,5-dichloro-p-xylylene glycol,
2,24-hydroxyethoxyphenyl)-propane and also polyoxyalkylene glycols
such as diethylene glycol, triethylene glycol, polyethylene glycol
and polypropylene glycol. The alkylene diols are preferably linear
and contain especially from 2 to 4 carbon atoms.
[0050] Polyoxyalkylene glycols having molecular weights of from 150
to 40 000 are also suitable.
[0051] As aromatic diols mention is made of those wherein two
hydroxy groups are bonded to one or to different aromatic
hydrocarbon radical(s).
[0052] Preferred diols are the alkylene diols, and
1,4-dihydroxycyclohexane and 1,4-bis(hydroxymethyl)cyclohexane.
Special preference is given to ethylene glycol, 1,4-butanediol, and
also 1,2- and 1,3-propylene glycol.
[0053] Further suitable aliphatic diols are the
.beta.-hydroxyalkylated, especially .beta.-hydroxyethylated,
bisphenols such as 2,2-bis[4'-(.beta.-hydroxyethoxy)phenyl]propane.
Further bisphenols are mentioned hereinafter.
[0054] A further group of suitable aliphatic diols comprises the
heterocyclic diols described in German Offenlegungsschriften 1 812
003, 2 342 432, 2 342 372 and 2 453 326. Examples are:
N,N'-bis(.beta.-hydroxyethyl)-5,5-dimethyl-hydantoin,
N,N'-bis(.beta.-hydroxpropyl)-5,5-dimethylhydantoin,
methylenebis[N-(.beta.-hydroxyethyl)-5-methyl-5-ethylhydantoin],
methylenebis[N-(.beta.-hydroxyethyl)-5,5-dimethylhydantoin],
N,N'-bis(.beta.-hydroxyethyl)benzimidazolone,
N,N'-bis(.beta.-hydroxyethyl)-(tetrachloro)-benzimidazolone and
N,N'-bis(.beta.-hydroxyethyl)-(tetrabromo)-benzimidazolone.
[0055] Suitable aromatic diols include mononuclear diphenols and,
especially, binuclear diphenols carrying a hydroxyl group on each
aromatic nucleus. "Aromatic" is understood to refer preferably to
hydrocarbon-aromatic radicals, for example phenylene or
naphthylene. Besides, for example, hydroquinone, resorcinol and
1,5-, 2,6- and 2,7-dihydroxynaphthalene, special mention should be
made of bisphenols that can be represented by the following
formulae:
##STR00009##
[0056] The hydroxyl groups may be in the m-position, but especially
in the p-position; R' and R'' in those formulae may be alkyl having
from 1 to 6 carbon atoms, halogen such as chlorine or bromine, and
especially hydrogen atoms. A can denote a direct bond or --O--,
--S--, --(O)S(O)--, --C(O)--, --P(O)(C.sub.1-C.sub.20alkyl)-,
unsubstituted or substituted alkylidene, cycloalkylidene or
alkylene.
[0057] Examples of unsubstituted or substituted alkylidene are:
ethylidene, 1,1- or 2,2-propylidene, 2,2-butylidene,
1,1-isobutylidene, pentylidene, hexylidene, heptylidene,
octylidene, dichloroethylidene and trichloroethylidene.
[0058] Examples of unsubstituted or substituted alkylene are
methylene, ethylene, phenylmethylene, diphenylmethylene and
methylphenylmethylene. Examples of cycloalkylidene are
cyclopentylidene, cyclohexylidene, cycloheptylidene and
cyclooctylidene.
[0059] Examples of bisphenols are: bis(p-hydroxyphenyl)ether or
thioether, bis(p-hydroxyphenyl)-sulfone,
bis(p-hydroxyphenyl)methane, bis(4-hydroxyphenyl)-2,2'-biphenyl,
phenylhydroquinone, 1,2-bis(p-hydroxyphenyl)ethane,
1-phenyl-bis(p-hydroxyphenyl)methane,
diphenyl-bis(p-hydroxyphenyl)methane,
diphenyl-bis(p-hydroxyphenyl)ethane,
bis(3,5-dimethyl-4-hydroxyphenyl)sulfone,
bis(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropylbenzene,
bis(3,5-dimethyl-4-hydroxyphenyl)-m-diisopropylbenzene,
2,2-bis(3',5'-dimethyl-4'-hydroxyphenyl)-propane, 1,1- or
2,2-bis(p-hydroxyphenyl)butane,
2,2-bis(p-hydroxyphenyl)hexafluoro-propane, 1,1-dichloro- or
1,1,1-trichloro-2,2-bis(p-hydroxphenyl)ethane,
1,1-bis(p-hydroxy-phenyl)cyclopentane and especially
2,2-bis(p-hydroxyphenyl)propane (bisphenol A) and
1,1-bis(p-hydroxyphenyl)cyclohexane (bisphenol C).
[0060] Suitable polyesters of hydroxycarboxylic acids are, for
example, polycaprolactone, polypivalolactone and the polyesters of
4-hydroxycyclohexanecarboxylic acid,
2-hydroxy-6-naphthalenecarboxylic acid or 4-hydroxybenzoic
acid.
[0061] Furthermore, polymers that may contain mainly ester bonds,
but also other bonds, for example polyester amides and polyester
imides, are also suitable.
[0062] Oligomers/polymers are obtained which contain, as structural
repeating unit, a group of formula A2
##STR00010##
wherein the substituents G.sub.1-G.sub.6 are as defined
hereinbefore, v is a number 2-200 and the meaning of G results from
the dicarboxylic acid used. Suitable dicarboxylic acids are
mentioned hereinbefore.
[0063] When a compound of formula B1 is reacted with the described
dicarboxylic acids and, optionally, further diols, polyester amides
are obtained having the structural repeating unit (B2)
##STR00011##
[0064] The definitions of the substituents are given
hereinbefore.
[0065] A third group of very suitable oligomers/polymers comprises
polyurethanes that are obtained by reacting diisocyanates with
compounds of formula A1 and, optionally, further diols.
[0066] Very suitable diisocyanates are 1,6-bis[isocyanato]hexane,
5-isocyanato-3-(isocyanato-methyl)-1,1,3-trimethylcyclohexane,
1,3-bis[5-isocyanato-1,3,3-trimethyl-phenyl]-2,4-dioxo-1,3-diazetidine,
3,6-bis[9-isocyanato-nonyl]-4,5-di(1-heptenyl)cyclohexene,
bis[4-isocyanato-cyclohexyl]methane,
trans-1,4-bis[isocyanato]cyclohexane,
1,3-bis[isocyanatomethyl]-benzene,
1,3-bis[1-isocyanato-1-methyl-ethyl]benzene,
1,4-bis[2-isocyanato-ethyl]cyclohexane,
1,3-bis[isocyanatomethyl]cyclohexane,
1,4-bis[1-isocyanato-1-methylethyl]benzene,
bis[isocyanato]isododecylbenzene, 1,4-bis[isocyanato]benzene,
2,4-bis[isocyanato]toluene, 2,6-bis[isocyanato]toluene,
2,4-/2,6-bis[isocyanato]toluene,
2-ethyl-1,2,3-tris[3-isocyanato-4-methyl-anilinocarbonyloxy]propane,
N,N'-bis[3-isocyanato-4-methylphenyl]urea,
1,4-bis[3-isocyanato-4-methylphenyl]-2,4-dioxo-1,3-diazetidine,
1,3,5-tris[3-isocyanato-4-methylphenyl]-2,4,6-trioxohexahydro-1,3,5-triaz-
ine,
1,3-bis[3-isocyanato-4-methylphenyl]-2,4,5-trioxoimidazolidine,
bis[2-isocyanatophenyl]methane,
(2-isocyanato-phenyl)-(4-isocyanato-phenyl)-methane,
bis[4-isocyanato-phenyl]methane,
2,4-bis-[4-isocyanatobenzyl]-1-isocyanatobenzene,
[4-isocyanato-3-(4-isocyanato-benzyl)-phenyl]-[2-isocyanato-5-(4-isocyana-
to-benzyl)-phenyl]methane, tris[4-isocyanato-phenyl]methane,
1,5-bis[isocyanato]-naphthalene and
4,4'-bis[isocyanato]-3,3'-dimethyl-biphenyl.
[0067] Especially preferred diisocyanates are
1,6-bis[isocyanato]hexane,
5-isocyanato-3-(isocyanatomethyl)-1,1,3-trimethylcyclohexane,
2,4-bis[isocyanato]toluene, 2,6-bis[isocyanato]-toluene,
2,4/2,6-bis[isocyanato]toluene or
bis[4-isocyanato-phenyl]methane.
[0068] Polyurethanes having the structural repeating unit (A3)
##STR00012##
are obtained. The substituents are defined hereinbefore. The
meaning of G results from the diisocyanates used.
[0069] Especially suitable individual compounds are mentioned
herein below, Table 1.
TABLE-US-00001 TABLE 1 Compound no. Structural formula 101
##STR00013## 102 ##STR00014## 103 ##STR00015## 104 ##STR00016## 105
##STR00017## 106 ##STR00018## 107 ##STR00019## 108 ##STR00020## 109
##STR00021## 110 ##STR00022## 111 ##STR00023## 112 ##STR00024## 113
##STR00025## 114 ##STR00026## 115 ##STR00027## 116 ##STR00028## 117
##STR00029## 118 ##STR00030## 119 ##STR00031## 120 ##STR00032## 121
##STR00033## 122 ##STR00034## 123 ##STR00035## 124 ##STR00036## 125
##STR00037## 126 ##STR00038## 127 ##STR00039## 128 ##STR00040## 129
##STR00041## 130 ##STR00042## 131 ##STR00043## 132 ##STR00044## 133
##STR00045## 134 ##STR00046## 135 ##STR00047## 136 ##STR00048## 137
##STR00049## 138 ##STR00050## 139 ##STR00051## 140 ##STR00052## 141
##STR00053## 142 ##STR00054## 143 ##STR00055## 144 ##STR00056## 145
##STR00057## 146 ##STR00058## 147 ##STR00059## 148 ##STR00060## 149
##STR00061## 150 ##STR00062## 151 ##STR00063## 152 ##STR00064## 153
##STR00065## 154 ##STR00066##
[0070] In a specific embodiment of the invention an additional
organic radical initiator is added.
[0071] Examples of free-radical initiators will be known to the
person skilled in the art and are commercially available, for
example:
[0072] 2,2'-azo-bis(2-methyl-butyronitrile)=AIBN,
2,2'-azo-bis(2,4-dimethylvaleronitrile),
2,2'-azo-bis(4-methoxy-2,4-dimethylvaleronitrile),
1,1'-azo-bis(1-cyclohexanecarbonitrile),
2,2'-azo-bis(isobutyramide) dihydrate,
2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile,
dimethyl-2,2'-azo-bisisobutyrate, 2-(carbamoylazo)isobutyronitrile,
2,2'-azo-bis(2,4,4-tri-methylpentane),
2,2'-azo-bis(2-methylpropane),
2,2'-azo-bis(N,N'-dimethylene-isobutyro-amidine) in the free base
or hydrochloride form, 2,2'-azo-bis(2-amidinopropane) in the free
base or hydrochloride form,
2,2'-azo-bis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide}
or
2,2'-azo-bis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxy-ethyl]propionam-
ide}. Acetylcyclohexane-sulfonyl peroxide,
diisopropyl-peroxy-dicarbonate, tert-amyl perneodecanoate,
tert-butyl perneodecanoate, tert-butyl perpivalate, tert-amyl
perpivalate, di(2,4-dichlorobenzoyl) peroxide, diisononanoyl
peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl
peroxide, di(4-methyl-benzoyl) peroxide, disuccinic acid peroxide,
diacetyl peroxide, dibenzoyl peroxide=BPO, tert-butyl per-2-ethyl
hexanoate, di(4-chloro-benzoyl) peroxide, tert-butyl
perisobutyrate, tert-butyl permaleinate,
1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane,
1,1-bis(tert-butylperoxy)cyclohexane, tert-butyl-peroxy-isopropyl
carbonate, tert-butyl perisononaoate,
2,5-dimethylhexane-2,5-dibenzoate, tert-butyl peracetate, tert-amyl
perbenzoate, tert-butyl perbenzoate, diisopropyl peroxydicarbonate,
bis(4-tert-butylcyclohexyl) peroxydicarbonate,
2,2-bis(tert-butylperoxy)butane, 2,2-bis(tert-butyl-peroxy)propane,
dicumyl peroxide=DCP, 2,5-dimethylhexane-2,5-di-tert-butyl
peroxide, 3-tert-butylperoxy-3-phenyl phthalide, di-tert-amyl
peroxide, 1,3-bis(tert-butylperoxy-isopropyl)benzene,
3,5-bis(tert-butylperoxy)-3,5-dimethyl-, 2-dioxolane, di-tert-butyl
peroxide, 2,5-dimethyl-hexyne-2,5-di-tert-butyl peroxide, n-butyl
4,4-di(tert-butylperoxy)valerate, ethyl
3,3-di(tert-butylperoxy)butyrate, di(1-hydroxycyclohexyl) peroxide,
dibenzyl peroxide, tert-butyl-cumyl peroxide,
3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxa-cyclononane, p-menthane
hydroperoxide, pinane hydroperoxide, diisopropylbenzene
mono-hydroperoxide, cumene hydroperoxide, methyl ethyl ketone
peroxide and tert-butyl hydroperoxide.
[0073] There may also be mentioned commercially available `C
free-radical-formers`, for example:
2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane or
poly-1,4-diisopropyl-benzene.
[0074] Where appropriate, combinations of such free-radical-formers
may also be used.
[0075] Particularly preferred are the organic peroxides selected
from the group consisting of isobutyryl-peroxide,
isopropylperoxy-dicarbonate, di-n-butylperoxy-dicarbonate,
di-sec-butylperoxy-dicarbonate, dicyclohexylperoxy-dicarbonate,
di(2-ethylhexyl)peroxy-dicarbonate, t-butyl-perneodecanoate,
t-butyl-perpivalate, bis(3,5,5-trimethyl-hexanoyl)peroxide,
didecanoyl-peroxide, dilauroyl-peroxide, t-butyl-perisobutyrate,
t-butyl-per2-ethylhexanoate, t-butyl-peracetate,
t-butyl-per-3,5,5-trimethylhexanoate, t-butyl-perbenzoate,
di-t-butyl-peroxide, t-butyl-hydroperoxide and
di-t-amylperoxide.
[0076] In another embodiment of the invention additionally a chain
transfer agent is added.
[0077] The chain transfer agent is, for example, selected from the
group consisting of ketones, aldehydes, C.sub.3-C.sub.20alkanes,
C.sub.3-C.sub.20alkenes, mercaptanes and disulfides.
[0078] Specific examples for sulfur containing compounds are
mercaptoethanol, dodecylmercaptane, dibenzylsufide, dibutylsulfide,
octadecyldisulfide, distearylthiodipropionate (Irganox PS 802),
dipalmityldithiodipropionate, dilaurylthiodipropionate
(Irganox.RTM. PS 800).
[0079] Most preferred is dodecylmercaptane.
[0080] Chain transfer agents are known and for example described in
"The Chemistry of Free Radical Polymerization", Ed. G. Moad, E.
Rizzardo, Pergamon 1995, pages 234-251. They are largely items of
commerce.
[0081] In a further embodiment of the invention the method is
carried out in the presence of a comonomer, which is selected from
a monomer containing a vinyl group, an allyl group, a vinylidene
group, a diene group or a olefinic group other than ethylene.
[0082] The term vinyl group containing monomer is understood to
mean in particular (meth)acrylates, vinylaromatic monomers,
vinylesters, vinyl ethers, (meth)acrylonitrile, (meth)acrylamide,
mono and di(C.sub.3-C.sub.18alkyl)(meth)acrylamides and monoesters
and diesters of maleic acid.
[0083] Mention may be made as examples of useful (meth)acrylates of
glycidyl, methyl, ethyl, 2,2,2-trifluoroethyl, n-propyl, isopropyl,
n-butyl, sec-buty, tert-butyl, n-amyl, i-amyl, n-hexyl,
2-ethylhexyl, cyclohexyl, octyl, i-octyl, nonyl, decyl, lauryl,
stearyl, phenyl, benzyl, .beta.-hydroxyethyl, isobornyl,
hydroxypropyl(meth)acrylates.
[0084] The term vinylaromatic monomer is understood to mean, for
example, styrene, vinyltoluene, .alpha.-methylstyrene,
4-methoxystyrene, 2-(hydroxymethyl)styrene, 4-ethylstyrene,
vinylanthracene.
[0085] Mention may be made as vinyl esters, of vinyl acetate, vinyl
propionate, vinyl chloride and vinyl fluoride, as vinyl ethers, of
vinyl methyl ether and vinyl ethyl ether.
[0086] An example of a vinylidene monomer is vinylidene
fluoride.
[0087] The term diene group containing monomer is understood to
mean a diene chosen from conjugated or nonconjugated, linear or
cyclic dienes, such as, for example, butadiene,
2,3-dimethyl-butadiene, 1,5-hexadiene, 1,9-decadiene,
5-methylene-2-norbornene, 1,5 cyclooctadiene or
4,7,8,9-tetrahydroindene.
[0088] Typically other olefinic monomers than ethylene are, for
example, propylene, 1-butene, 4-methyl-1-pentene, octene or
1-decene.
[0089] Further comonomers may be maleic acid anhydride, fumaric
acid anhydride or itaconic acid anhydride and N-alkyl or
N-arylmaleimide.
[0090] Particularly preferred comonomers are methylacrylate,
ethylacrylate, n-butylacrylate, vinylacetate, styrene,
a-methylstyrene and methylmethacrylate.
[0091] The proportion of comonomers for the preparation of random
copolymers of ethylene may be in general from 0 to 90% by weight,
preferably from 0 to 50% by weight and in particular from 0 to 10%
by weight.
[0092] A further aspect of the invention is the use of a
hydroxylamine ester containing a structural element of formula (I)
or (I') as radical forming species for the continuous or batch wise
polymerization or copolymerization of ethylene at an operating
pressure of from 500 to 3500 bar, at a polymerization temperature
between 100.degree. and 400.degree. C. in a suitable high pressure
reactor.
[0093] The following examples illustrate the invention.
General Polymerization Procedure
[0094] The ethylene polymerization experiments are carried out in a
continuously operating laboratory plant. The center piece is a
small stirred tank autoclave with jacket heating and 15 mL
capacity. The polymerizations can be carried out at pressures up to
3000 bar and temperatures up to 300.degree. C. The ethylene is
compressed by means of a multistage diaphragm compressor. The
initiator is dissolved in dry hexane and passed into the reactor
through a metering device. Polymer samples can be separated from
the reactor by a heated needle valve at the bottom of the
autoclave. The formed polymer is separated from the unreacted
ethylene by pressure release and the amount (conversion) is
determined by gravimetry. The reaction parameters, mass flows and
valves are computer controlled.
[0095] All polymerization experiments are carried out at a pressure
of 1800 bar, the mean residence time in the autoclave is 120 sec.
The corresponding polymerization temperatures can be taken from
Table 1. The initiator consumption (efficiency) per kg polymer can
be calculated from the conversion and the amount of initiator
used.
[0096] Molecular weights and molecular weight distributions (PD)
are determined by gel permeation chromatography in trichlorobenzene
(140.degree. C.) calibrated with polystyrene standards.
[0097] The hydroxylamine ester used is compound 139, prepared
according to WO 01/90113
TABLE-US-00002 TABLE 1 Compound 139: ##STR00067## reaction
conditions and analysis of LDPEs manufactured by high pressure
polymerization of ethylene initiated by compound 139 Compound
Reaction Con- Initiator Number of MVR* 139/ Temp./ version/
efficiency/ M.sub.n/ M.sub.w/ PD branches 190/21.6/ Specimen mol
ppm .degree. C. % g/kg.sub.polymer g/mol g/mol -- CH.sub.3/1000C
cm.sup.3/10 min Example 1 15 205 13 1.3 8.45E + 04 3.67E + 05 4.3
22.5 0.34 Example 2 30 170 1.5 22.3 8.11E + 04 2.84E + 05 3.5 17.9
** Example 3 15 170 1.4 12.4 1.16E + 05 3.89E + 05 3.4 15.3 **
Example 4 30 160 2.7 25.1 2.02E + 05 5.47E + 05 2.7 15.6 <0.1
Lupolen 2420 F -- -- -- -- 79.9 (commerical prod.)*** Comparative
-- 230 28.8 0.6 2.32E + 04 1.87E + 05 8.1 14.1 10.9 example****
*according to ISO1133 **not determined ***producer: Basell
Polyolefins ***initiated by 30 mol ppm t-butylperbenzoate
[0098] The data in Table 1 show that polymerizations carried out
according to the invention lead to polyethylenes having high
molecular weights (small MVR values) and narrow molecular weight
distributions (PDs) whereas the polymer specimen from the
comparative example as well as the commercial product show very
broad PDs at even lower molecular weights.
* * * * *