Note: Descriptions are shown in the official language in which they were submitted.
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Heavy metal-free coating formulations
The present invention relates to heavy metal-free UV-curable, cationically
polymerisable
compositions and to their use.
In J. of Photopolym. Sci. and Techn., Vol. 5 (1992}, p. 247-254, F. Hamazu et
al. published
investigations regarding the reactivity of sulfonium salts containing
different anions. A curing
process for cationically curable pigmented formulations is known from WO
98/02493. JP-A
Sho 61-175921 describes back coatings for magnetic recording materials based
on glycidyl
ether formulations. US 4378277 discloses unpigmented photocurable formulations
com-
prising glycidyl ether and a mixture of initiator compounds. US 4287228
describes glycidyl
ether-containing compositions pigmented with titanium dioxide. WO 96/13538
discloses
cationically polymerisable formulations using aryl iodonium salts as
initiators and dicarbonyl
compounds as sensitisers.
The technology has a demand for formulations which are radiation-curable,
reactive, catio-
nically curable, inexpensive, white and hardly yellowing, especially for use
as coatings.
It has been found that the above requirements are fully met by a composition,
which
comprises
(a) mono-, bis- or higher aliphatic or aromatic glycidyl ethers,
(b) titanium dioxide,
(c) at least one iodonium hexafluorophosphate salt as photoinitiator, and
(d) a sensitiser compound.
The photoinitiator (c) is, for example, a compound of formula I
R~
+ -
R2 PFs (I), wherein
R3
R,, RZ, R3 and R4 are each independently of one another hydrogen, C,-CZOalkyl
or unsub-
stituted or hydroxyl-substituted C~-CZOalkoxy, with the proviso that at least
one of R,, RZ, R3
or R, is not hydrogen.
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C,-C2oAlkyl is linear or branched and is, for example, C,-C,2-, C,-Ca-, C,-C6-
or C,-C4alkyl.
Examples are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl,
tert-butyl, pentyl,
hexyl, heptyl, 2,4,4-trimethylpentyl, 2-ethylhexyl, octyl, nonyl, decyl,
undecyl, dodecyl, tetra-
decyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl or eicosyl.
Branched alkyl is
preferred, in particular C3-C8-, C3-Cs- and C3-C4alkyl. R2 and R4 are, for
example, C,-C,2alkyl,
C,-Csalkyl or C,-Csalkyl, preferably C,-C4alkyl, such as isobutyl, or C,-
C,2alkyl, such as
dodecyl.
C,-CzoAlkoxy is a linear or branched radical and is, for example, C,-C,2-, C,-
C8-, C,-Cs- or
C,-C4alkoxy. Examples are methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy,
sec-butyloxy,
isobutyloxy, tert-butyloxy, pentyloxy, hexyloxy, heptyloxy, 2,4,4-
trimethy~entyloxy, 2-ethyl-
hexyloxy, octyloxy, nonyloxy, decyloxy, dodecyloxy, hexadecyloxy or
octadecyloxy, prefer
ably methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy, sec-butybxy,
isobutyloxy, tert-butyl-
oxy, more preferably methoxy. Preferred compounds are, for example, n-C4-C6-,
n-C,-Cs-, n-
Cz-Cs-, n-C,-C4- n-C2-C4alkoxy. n-C,2-CZOAlkoxy is also interesting.
Compounds of formula I to be highlighted are those, wherein R,, R2, R3 and R4
are C,-C2o-
alkyl, preferably C,-C,Zalkyl.
Other interesting compounds are those of formula I, wherein R,, R2, R3 and R4
are branched
C,-C2oalkyl, preferably branched C,-C,Zalkyl or branched C,-C4alkyl.
Preferred compounds of formula I are those, wherein R2 and R4 are C,-C2oalkyl,
and R, and
R3 are hydrogen.
Other interesting compounds of formula I are those, wherein R2 and R, are
identical.
Those compounds of formula I merit particular mention, wherein R2 is C,-
C,2alkyl, preferably
isobutyl or dodecyl, and R,, R3 and R4 are hydrogen.
Other particularly preferred compounds of formula I are those, wherein R2 and
R4 are C,-C,2-
alkyl, such as isobutyl or dodecyl.
Preferred compounds of formula I are those, wherein R2 is C,-C4alkyl if R,, R2
and R3 are
hydrogen.
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Other preferred compounds of formula I are those wherein R2 is C,-C4alkoxy if
R,, R2 and R3
are hydrogen. Those compounds of formula I are also preferred wherein R2 is
C,o-CZOalkoxy
if R,, R2 and R3 are hydrogen.
Examples of compounds of formula I are
bis(4-hexylphenyl)iodonium hexafluorophosphate; (4-hexylphenyl)phenyl iodonium
hexa~
fluorophosphate; bis(4-octylphenyl)iodonium hexafluorophosphate; (4-
octylphenyl)phenyl
iodonium hexafluorophosphate; bis{4-decylphenyl)iodonium hexafluorophosphate;
(4-isobu-
tylphenyl)phenyl iodonium hexafluorophosphate; bis(4-isobutylphenyl)iodonium
hexafluoro-
phosphate; (4-dodecylphenyl)phenyl iodonium hexafluorophosphate; (2-
hydroxydodecyloxy-
phenyl)phenyl iodonium hexafluorophosphate; (2-
hydroxytetradecyloxyphenyl)phenyl iocbni-
um hexafluorophosphate.
This invention also relates to (4-isobutylphenyl)phenyl iodonium
hexafluorophosphate, in
particular dissolved in propylene carbonate.
In certain cases it may be advantageous to use mixtures of two or more of such
iodonium
salt photoinitiators in the compositions of this invention.
The preparation of the photoinitiator compounds of formula I is familiar to
the skilled person
and is described in the literature. Thus, compounds of formula I can be
prepared, for exam-
ple, by the process described in US patents 4399071 and 4329300 and in DE
2754853. The
hexafluorophosphate salts can be prepared, for example, by exchanging the
anions of the
simple salts of the corresponding iodonium compounds (e.g. those of the
bisulfates). These
methods have been published, inter alia, by Beringer et al. in J. Am. Chem.
Soc. 81, 342
(1959). This literature also describes different methods for the preparation
of the above-
mentioned simple salts, for example the reaction of two aromatic compounds
with iodyl sul-
fate in sulfuric acid; the reaction of two aromatic compounds with iodate in
acetic acid, acetic
anhydride, sulfuric acid; the reaction of two aromatic compounds with iodine
acylate in the
presence of an acid, or the condensation of a iodosyl compound, of a iodosyl
diacetate or of
a iodoyl compound with another aromatic compound in the presence of an acid.
in some cases it is also possible to oxidise an aryl iodide in situ and to
then condense it with
another aromatic compound. This variant of the condensation proceeds, for
example, in
dilute sulfuric acid (EP 119 068).
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In the compositions of this invention, the photoinitiator (c) is conveniently
used in an amount
from 0.05% to 15%, for example from 0.5% to 10%, preferably from 0.1 % to 5%,
based on
the composition.
The glycidyl ether components (a) used in the novel formulations are typically
gfycidyl ethers
of polyvalent phenols obtained by reacting polyvalent phenols with an excess
of chlorohyd-
rin, such as epichlorohydrin (e.g. glycidyl ether of 2,2-bis(2,3-
epoxypropoxyphenol)propane.
Other examples of glycidyl ether epoxides which can be used in connection with
this inven-
tion are described, inter alia, in US 3018262 and in "Handbook of Epoxy
Resins" by Lee and
Neville, McGraw-Hill Book Co., New York (1967).
There are also numerous commercially available glycidyl ether epoxides which
can be used
as component {a), for example glycidyl methacrylate, diglycidyl ether of
bisphenol A, e.g.
those obtainable under the tradenames EPON 828, EPON 825, EPON 1004 and EPON
1010, of Shell; DER-331, DER-332 and DER-334, of Dow Chemical; 1,4-butanediol
diglycidyl
ether of phenolformaldehyde novolak, e.g. DEN-431, DEN-438, of Dow Chemical;
and resor-
cinol diglycidyl ether; alkyl glycidyl ether, such as CB-C,oglycidyl ether,
e.g. HELOXY modifier
7, C,2-C,4glycidyl ether, e.g. HELOXY modifier 8, butyl glycidyl ether, e.g.
HELOXY modifier
61, cresyi glycidyl ether, e.g. HELOXY modifier 62, p-tert-butylphenyl
glycidyl ether, e.g.
HELOXY modifier 65, polyfunctional glycidyl ethers, for example diglycidyl
ether of 1,4-bu-
tanediol, e.g. HELOXY modifier 67, diglycidyl ether of neopentyl glycol, e.g.
HELOXY modi-
fier 68, diglycidyl ether of cyclohexanedimethanol, e.g. HELOXY modifier 107,
trimethylol-
ethane triglycidyl ether, e.g. HELOXY modifier 44, trimethylolpropane
triglycidyl ether, e.g.
HELOXY modifier 48, polyglycidyl ether of aliphatic polyols, e.g. HELOXY
modifier 84 (all
HELOXY glycidyl ethers are available from Shell).
Other suitable glycidyl ethers are those containing copolymers of acrylates,
for example
styrene glycidyl methacrylate or methyl methacrylate glycidyl acrylate.
Examples are 1:1
styrene/glycidyl methacrylate, 1:1 methyl methacrylate/glycidyl acrylate,
62.5:24:13.5 methyl
methacrylate/ethyl acrylate/glycidyl methacrylate.
The polymers of the glycidyl ether compounds can, for example, also contain
other functio-
nalities, provided they do not impair the cationic cure.
Other glycidyl ether compounds suitable as component (a) and commercially
available from
Ciba Spezialitatenchemie are polyfunctional liquid and solid novolak glycidyl
ether resins, for
example PY 307, EPN 1179, EPN 1180, EPN 1182 and ECN 9699.
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It is, of course, also possible to use mixtures of different glycidyl ether
compounds as com-
ponent (a).
The glycidyl ethers (a) are, for example, compounds of formula II
~O'
HzC H-CH2 O x RS (II), wherein
x is a number from 1 to 6; and
R5 is a monovaient to hexavalent alkyl or aryl radical.
The glycidyl ethers (a) are preferably e.g. compounds of formula II
~O~
H2C H-CH2 O x R5 (II}, wherein
x is a number from 1, 2 or 3; and
R5, if x = 1, is unsubstituted or C,-C,Zalkyl-substituted phenyl, naphthyl,
anthracyl, biphenyl-
yl, C~-CZOalkyl, or C2-C2oalkyl which is interrupted by one or more than one
oxygen atom, or
R5, if x = 2, is 1,3-phenylene, 1,4-phenylene, CB-C,ocycloalkylene,
unsubstituted or halogen-
substituted C,-C~alkylene; C2-C4oalkylene which is interrupted by one or more
than one
oxygen atom, or a group ~ ~ Rs ~ ~ , or
i 2Hs ~Ha
R5, if x = 3, is a radical -C-C-C- , -C-C-C- , or
H2 ~ H2 H2 ~ H2
C- C-
HZ HZ
H2 i -EO-CH2 CH(CH~-y--
H i -~O-CHZ CH(CH3)~ ;
H-EO-CH2 CH(CH~
z
y is a number from 1 to 10; and
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O '
H2C-H-CH2
Re is C,-C2oalkylene, oxygen or
The glycidyl ethers (a) are, for example, compounds of formula Ila
O
R O-C C~ \CH (Ila), wherein
H2 H
R~ is unsubstituted or C,-C,Zalkyl-substituted phenyl; naphthyl; anthracyl;
biphenylyl; C,-C2o-
alkyl; C2-C2Qalkyl which is interrupted by one or more than one oxygen atom;
or a group of
O
formula H2C~ \H-CHZ O-R5 ;
RS is phenyiene, C,-C2oalkylene; C2-Czoalkylene which is interrupted by one or
more than
one oxygen atom, or a group ~ ~ R6 ~ ~ ; and
R6 is C,-C2oalkylene or oxygen.
Preferred glycidyl ethers are the compounds of formula Ilb
O O
H2C \H-CH2 O-RS O-H H~ ~CH2 (Ilb), wherein
2
R5 is phenylene, C,-C2oalkylene; C2-CZaalkylene which is interrupted by one or
more than
one oxygen atom, or a group ~ ~ RB ~ ~ ; and
Rg is C,-C~alkylene or oxygen.
Alkyl radicals are, for example, C,-CZOalkyl, C,-C,8-, C,-C,2-, C,-C,o-, C,-C8-
, C,-Cs- or C,-
C4alkyl. Meanings of these radicals are given above.
C,-C2oAlkylene is linear or branched and is, for example, C,-C,8-, C,-C,6-, C,-
C,4-, C,-C,2-, C,-
C,o-, C,-C8-, C,-CB-, C2-C,Z-, C2-Ce-, C,-C~- or C,-C,alkylene. Examples are
methylene,
ethylene, propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-
butylene,
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pentylene, hexylene, heptylene, octylene, nonylene, decylene, dodecylene,
tetradecylene,
heptadecylene or octadecylene. C,-C2oAlkylene is preferably understood to mean
e.g.
CH3
ethylene, decylene, -CH- , -CH-CHZ- -C- , -CH-(CH2)Z ,
C»Hza CHs CH3 CH3
C2H5
-CH-(CH2)3 , -C(CH3)rCH2- or -CHZ C-CH2
CH3 CH3
Halogen is fluoro, chloro and bromo, preferably bromo and chloro, most
preferably bromo.
CH2Br
Halogen-substituted C,-C4oalkylene is, for example, -CH2'-~-' CH2-
CH2Br
C2-C2oAlkylene which is interrupted by one or more than one oxygen atom is
also linear or
branched and is interrupted, for example, one to nine times, one to five times
or once or
twice by non-consecutive oxygen atoms. This gives structures such as -CH2-O-
CH2-,
-CH2CH2-O-CH2CH2-, -[CH2CH20~y , where y = 1-9, -(CH2CH20),CH2CH2-, or
-CHz-CH(CH3)-O-CH2-CH{CH3)-.
Cs-C,oCycloalkylene is for example 1,4-, 1,3- or 1,6- cyclohexylene, or also
-Hz HZ or -cZHs c2H5 , wherein the alkylene radicals are preferably
in 1,4-position.
RS is preferably a group ~ ~ R6 ~ ~
H3
Rs is preferably C,-C,2alkylene, more preferably -~- , or oxygen.
I
CH3
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Other examples of component (a) are polyglycidyl ether and polyp-
methylglycidyl)ether
which are obtainable by reacting a compound containing at least two free
alcoholic and/or
phenolic hydroxyl groups per molecule with the corresponding epichlorohydrin
under alkaline
conditions, or also in the presence of an acid catalyst with subsequent
treatment with alkali.
It is also possible to use mixtures of different polyols.
These ethers can be prepared with poly(epichlorohydrin) from acyclic alcohols,
such as
ethylene glycol, diethylene glycol and higher poly(oxyethylene)glycol, propane-
1,2-diol and
poly(oxypropylene)glycols, propane-1,3-diol, butane-1,4-diol,
poly(oxytetramethylene)glycols,
pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-triol, glycerol, 1,1,1-
trimethylolpropane, pen-
taerythritol and sorbitol, from cycloaliphatic alcohols, such as resorcitol,
quinitol, bis(4-hydro-
xycyclohexyl)methane, 2,2-bis(4-hydroxycyclohexyl)propane and 1,1-
bis(hydroxymethyl)cyc-
lohex-3-ene, and from alcohols containing aromatic nuclei, such as N,N-bis(2-
hydroxyethyl)-
aniline and p,p'-bis(2-hydroxyethylamino)diphenylmethane. It is also possible
to prepare
these ethers from mononuclear phenols, such as resorcinol and hydroquinone,
and from
polynuclear phenols, such as bis(4-hydroxyphenyl)methane, 4,4-
dihydroxydiphenyl, bis(4-
hydroxyphenyl)sulfone, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 2,2-bis(4-
hydroxyphenyl)-
propane (bisphenol A) and 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane.
Other suitable hydroxy compounds for the preparation of polyglycidyl ethers
and poly(~i-me-
thylglycidyl)ethers are the novolaks obtainable by condensing aldehydes, such
as formalde-
hyde, acetaldehyde, chloral and furfural, and phenols, such as phenol, o-
cresol, m-cresol, p-
cresol, 3,5-dimethylphenol, 4-chlorophenol and 4-tert-butylphenol.
Poly(N-glycidyl) compounds can be obtained, for example, by
dehydrochlorinating the reac-
tion products of epichlorohydrin with at least two amines containing active
hydrogen bound
to amino nitrogen atoms, for example aniline, n-butyiamine, bis(4-
aminophenyl)methane and
bis(4-methylaminophenyl)methane. Other suitable poly(N-glycidyl) compounds are
triglycidyl
isocyanurate and N,N'-diglycidyl derivatives of cyclic alkylene ureas, such as
ethylene urea
and 1,3-propylene urea, and hydantoins, for example 5,5-dimethylhydantoin.
Poly{S-giycidyl) compounds are also suitable. Examples are the di-S-glycidyl
derivatives of
dithiols, such as ethane-1,2-dithiol and bis(4-mercaptomethylphenyl)ether.
Other suitable components (a) are also epoxy resins in which the glycidyl
groups or (i-me-
thylglycidyl groups are bound to different kinds of heteroatoms, e.g. the
N,N,O-triglyci dyl de-
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rivative of 4-aminophenol, the glycidyl ether/glycidyl ester of salicylic acid
or p-hydroxyben-
zoic acid, N-glycidyl-N'-(2-glycidyloxypropyl)-5,5-dimethylhydantoin and 2-
glycidyloxy-1,3-bis-
(5,5-dimethyl-1-glycidylhydantoinyl-3)propane.
The diglycidyl ethers of bisphenols are preferred. Examples thereof are
diglycidyl ethers of
bisphenol A, such as ARALDIT GY 250, of Ciba Spezialitatenchemie, diglycidyl
ether of bis-
phenol F and diglycidyl ether of bisphenol S. Diglycidyl ether of bisphenol A
is particularly
preferred.
If desired, the composition can also contain a free-radically polymerisable
material, in-
cluding ethylenically unsaturated monomers, oligomers or polymers. Suitable
materials
contain at least one ethylenically unsaturated double bond, and are capable of
undergo-
ing addition polymerisation. Such free-radically polymerisable materials
include mono-, di-
or polyacrylates and mono-, di- or polymethacrylates such as methylacrylate,
methyl
methacrylate, ethylacrylate, isopropyl methacrylate, n-hexylacrylate,
stearylacrylate, allyi-
acrylate, glycerol diacrylate, glycerol triacrylate, ethylene glycol
diacryiate, diethylene gly-
col diacrylate, triethylene glycol dimethacrylate, 1,3-propanedioldiacrylate,
1,3-propane-
diol dimethacrylate, trimethylolpropanetriacrylate, 1,2,4-
butanetrioltrimethacrylate, 1,4-
cyclohexanedioldiacrylate, pentaerythritol triacrylate, pentaerythritol
tetraacrylate, penta-
erythritol tetramethacrylate, sorbitol hexacrylate, bis[1-(2-acryloxy)]-p-
ethoxyphenyldime-
thylmethane, bis[1-(3-acryloxy-2-hydroxy)]-p-propoxyphenyldimethylmethane, and
tris~
hydroxyethylisocyanurate trimethacrylate; the bisacrylates and
bismethacrylates of poly-
ethylene glycols having a molecular weight of 200-500, copolymerisable
mixtures of acry-
lated monomers; and vinyl compounds such as styrene, diallyl phthalate,
divinyl succi-
nate, divinyl adipate and divinyl phthalate. Mixtures of two or more of these
free-radically
polymerisable materials can be used, if desired.
If free-radically polymerisable components are added to the novel formulation,
then it is
useful to also add one, or a mixture of, corresponding radical
photoinitiator(s), for example
benzophenone and benzophenone derivatives, acetophenone and acetophenone
deriva-
tives, such as a-hydroxycyclohexylphenylketone or 2-hydroxy-2-methyl-1-
phenylpropanone,
a-hydroxy- or a-aminoacetophenone, such as (4-methylthiobenzoyl)-1-methyl-1-
morpholino
ethane, (4-morpholinobenzoyl)-1-benzyl-1-dimethylaminopropane, 4-aroyl-1,3-
dioxolanes,
benzoinalkyl ether and benzilketal, such as benzildimethylketal,
phenylglyoxalate and phe-
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nylglyoxalate derivatives, mono- or bisacylphosphine oxide, such as (2,4,6-
trimethylbenzoyl}-
phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-(2,4,4-trimethylpent-1-
yi)phosphine
oxide, bis(2,4,fi-trimethylbenzoyl)phenylphosphine oxide or bis(2,4,6-
trimethylbenzoyl)-(2,4-
dipentoxyphenyl)phosphine oxide.
The novel compositions can also contain vinyl ether monomers such as
cyclohexanedime-
thanol divinyl ether or hydroxybutyl vinyl ether.
Other additional components may be, for example, hydroxy-functional components
such as
alcohols, polyester polyols, polyether polyols, castor oil and the like.
Examples are aliphatic
and cycloaliphatic polyols such as alkylenediols containing preferably 2 to 12
carbon atoms,
e.g. ethylene glycol, 1,2- or 1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol,
pentanediol, hex-
anediol, octanediol, dodecanediol, diethylene glycol, triethylene glycol,
polyethylene glycols
having molecular weights from preferably 200 to 1500, 1,3-cyclopentanediol,
1,2-, 1,3- or
1,4-cyclohexanediol, 1,4-dihydroxymethylcyclohexane, glycerol, tris((i-
hydroxyethyl)amine,
trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol and
sorbitol. The
polyols can be partially or completely esterified with one or different
unsaturated carboxylic
acids, it being possible for the free hydroxyl groups in partial esters to be
modified, for exam-
ple etherified or esterified, with other carboxylic acids. Examples of esters
are: trimethylol-
propanetriacrylate, trimethylolethanetriacrylate,
trimethylolpropanetrimethacrylate, trimethyl-
olethanetrimethacrylate, tetramethylene glycol dimethacrylate, triethylene
glycol dimethacry-
late, tetraethylene glycol diacrylate, pentaerythritol diacrylate,
pentaerythritol triacrylate, pen-
taerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol
triacrylate, dipentaery-
thritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol
hexaacrylate, tripenta-
erythritol octaacrylate, pentaerythritol dimethacrylate, pentaerythritol
trimethacrylate, dipen-
taerythritol dimethacrylate, dipentaerythritol tetramethacrylate,
tripentaerythritol octameth-
acrylate, pentaerythritol diitaconate, dipentaerythritol trisitaconate,
dipentaerythritol penta-
itaconate, dipentaerythritol hexaitaconate, ethylene glycol diacrylate, 1,3-
butanedioldiacry
late, 1,3-butanedioldimethacrylate, 1,4-butanedioldiitaconate, sorbitol
triacrylate, sorbitol
tetraacrylate, pentaerythritol-modified triacrylate, sorbitol
tetramethacryfate, sorbitol penta-
acrylate, sorbitol hexaacrylate, oligoester acrylate and oligoester
methacrylate, glycerol di-
and -triacrylate, 1,4-cyclohexanediacrylate, bisacrylates and bismethacrylates
of polyethy-
lene glycol having a molecular weight of 200 to 1500, or mixtures thereof.
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Components (a) of particular interest are pure glycidyl ether formulations,
i.e. mixtures
consisting only of one or several different glycidyl ether compounds.
The titanium dioxide pigment (b) can be added to the novel compositions in a
very wide
range of forms. Thus, it can be incorporated, for example, in the form of fine
particles or
powders. The particle size is usefully from 100 to 400 nm, but is not
restricted to these sizes.
The titanium dioxide pigments used are preferably surface-treated, for example
with stabili-
sers, to increase their dispersibility. Such stabiliser components are usually
oxides or hydra-
ted oxides of silicium, magnesium or aluminium, or amines or other organic
compounds.
Examples thereof are cited in US 4054498. Although the titanium dioxide can be
present in
different crystalline forms, it is preferred to use the rutile form which is
also commercially
available.
The amount of titanium dioxide component (b) in the polymerisable composition
can vary
within a wide range, depending on the desired opacity, for example from 5% to
60%, typi-
cally from 20 % to 55%, preferably from 40 % to 50%, based on the composition.
In order to improve the dispersion of the pigment in the formulation to be
polymerised, it is
possible, for example, to first predisperse the pigment in part of the
formulation and then to
incorporate this dispersion into the remainder of the formulation.
Suitable sensitiser compounds (d) are, for example, compounds from the class
of the aro-
matic hydrocarbons, such as anthracene and its derivatives, from the group of
the xanthones
and their derivatives, benzophenones and their derivatives, for example
Michler's ketone,
Mannich bases or bis(p-N,N-dimethylaminobenzylidene)acetone. Other suitable
compounds
are thioxanthone and its derivatives, such as isopropylthioxanthone, or dyes,
such as acri-
dines, triarylmethanes, e.g. malachite green, indolines, thiazines, e.g.
methylene blue,
oxazines, phenazines, e.g. safranin, or rhodamines. Particularly suitable
compounds are
aromatic carbonyl compounds, such as the benzophenone, thioxanthone,
anthraquinone
and 3-acylcoumarine derivatives, and also 3-(aroylmethyiene)thiazolines, as
well as eosine,
rhodamine and erythrosine dyes.
The sensitiser compound should be soluble in the photopolymerisable
composition and
should be free of functional groups which crucially influence the cationic
crosslinking pro-
cess. The light absorption of the compounds should furthermore be in the range
of about
300 to 1000 nm.
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Suitable sensitisers are (as mentioned above to some extent) compounds of the
following
classes: ketones, coumarines (e.g. ketocoumarine), xanthones, acridines,
thiazole dyes,
thiazine dyes, oxazine dyes, azine dyes, aminoketone dyes, porphyrines,
aromatic polycyclic
hydrogens, p-substituted aminostyryl ketone compounds, aminotriarylmethanes,
merocya-
nines, squarylium dyes and pyridinium dyes. Preferred compounds are ketones
(e.g. mono-
ketone or a-diketone), ketocoumarines, aminoarylketones and p-substituted
aminostyryl
ketone compounds. For applications requiring a deep cure (e.g, curing of
highly filled com-
posite materials), it is preferred to use sensitisers having an extinction
coefficient of less than
about 1000 Imol''cm'', preferably of less than about 100 Imol''cm'', at the
desired radiation
wavelength for the photopolymerisation. The a-diketones are one example of a
class of
sensitisers possessing these properties.
Suitable ketone sensitisers are, for example, those of formula IV
O
A-C-(X)b Z (IV), wherein
X is CO or CReRb,
Ra and Rb are each independently of the other hydrogen, alkyl, alkaryl, or
aralkyl;
b is 1 or 2; and
A and Z are each independently of the other aryl, alkyl, alkaryl or aralkyl,
which groups are
unsubstituted or substituted, or A and Z together form a ring which is
substituted or unsub-
stituted, cycloaliphatic, aromatic or heteroaromatic.
Suitable ketones of this formula are, for example, monoketones (b=0) such as
2,2-, 4,4- or
2,4-dihydroxybenzophenone, dipyridylketone, difuranylketone,
dithiophenylketone, benzoin,
fluorenone, chalcone, Michler's ketone, thioxanthone, isopropylthioxanthone, 2-
fluoro-9-
fluorenone, 2-chlorothioxanthone, acetophenone, benzophenone, 1- or 2-
acetonaphthone,
9-acetylanthracene, 2-, 3- or 9-acetylphenanthrene, 4-acetylbiphenyl,
propiophenone,
n-butyrophenone, valerophenone, 2-, 3- or 4-acetylpyridine, 3-acetylcoumarine
and the like.
Suitable diketones include aralkyldiketones such as anthraquinone,
phenanthrenequinone,
o-, m- and p-diacetylbenzene, 1,3-, 1,4-, 1,5-, 1,6-, 1,7- and 1,8-
diacetylnaphthalene, 1,5-,
1,8- and 9,10-diacetylanthracene and the like. Suitable diketones (b=i and
X=CO) include
2,3-butanedione, 2,3-pentanedione, 2,3-hexanedione, 3,4-hexanedione, 2,3-
heptanedione,
3,4-heptanedione, 2,3-octanedione, 4,5-octanedione, benzile, 2,2'-, 3,3'- and
4,4'-dihydroxy-
benzile, furile, di-3,3'-indoiylethanedione, 2,3-bornanedione
{camphorquinone), biacetyl,
1,2-cyclohexanedione, 1,2-naphthaquinone, acenaphthaquinone and the like.
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Preferred sensitisers are those of the group of the anthracenes, xanthones,
benzophenones
and thioxanthones, also including the derivatives of these compounds.
Thioxanthones are
particularly preferred, in particular isopropylthioxanthone.
The sensitiser compound (d) is usefully added to the novel compositions in an
amount from
0.1 %-3%, e.g. from 0.2%-1.5%, preferably from 0.4%-1.0%.
The novel composition conveniently comprises 40-70% of the glycidyl ether
component (a),
20-60% of the titanium dioxide (b), 0.5-10% of the photoinitiator (c) and 0.1-
3% of the sensi-
tiser compound (d).
Other additives may be added to the novel compositions besides components (a),
(b), (c)
and (d). Examples thereof are light stabilisers, for example UV absorbers such
as those of
the hydroxyphenylbenztriazole, hydroxyphenylbenzophenone, oxalic acid amide or
hydroxy-
phenyl-s-triazine type. These compounds can be used separately or as mixtures,
with or
without addition of sterically hindered amines (HALS).
The novel compositions can contain as additional additive, inter alia, an
electron-donor com-
pound. Examples of such compounds are described in US 5545676. Examples are
alkyl-
aromatic polyethers or alkyl-aryl-amino compounds, wherein the aryl group is
substituted by
one or several electron-attracting group(s). Examples thereof are 4-
dimethylaminobenzoic
acid, ethyl 4-dimethylaminobenzoate, 3-dimethylaminobenzoic acid, 4-
dimethylaminoben-
zoin, 4-dimethylaminobenzaldehyde, 4-dimethylaminobenzonitrile and 1,2,4-
trimethoxyben-
zene.
Other customary additives are - depending on the end use requirements -
fluorescent
whitening agents, fillers, dyes, wetting agents or flow control agents. The
novel compositions
may contain as further additives dispersants, emulsifiers, antioxidants, light
stabilisers, dyes,
pigments, fillers, e.g. talcum, gypsum, silicic acid, rutile, carbon black,
zinc oxide, iron
oxides, reaction accelerators, flow control agents, wetting agents,
thickeners, flatting agents,
antifoams, antioxidants and other auxiliaries customarily used in the paint
system technolo-
gy. Suitable dispersants are, for example, high molecular weight organic
compounds con-
taining polar groups, such as polyvinyl alcohols, polyvinyl pyrrolidone or
cellulose ether.
Suitable emulsifiers are non-ionic or ionic emulsifiers.
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The choice of the additives depends on the respective field of applications
and on the pro-
perties desired in this field. The additives are standard in the technology
and are thus used
in amounts known to the skilled person.
The novel compositions can be used in different fields, for example in coating
materials,
laminating adhesives, in printing inks, white enamel formulations, for example
for wood or
metal, or in paints used, inter alia, for paper, wood, metal or plastic
materials.
The compositions of this invention can be used to coat or bond substrates of
all kinds, for
example wood, textiles, paper, ceramics, glass, plastic materials, such as
polyester, poly-
ethylene terephthalate, polyolefins or cellulose acetate, in particular in the
form of films, and
metals such as AI, Cu, Ni, Fe, Zn, Mg or Co and GaAs, Si or Si02 to which a
protective
coating is to be applied.
The substrates can be coated by applying a liquid composition, a solution or
suspension to
the substrate. The choice of solvent used and its concentration depends mainly
on the type
of composition and on the coating process used. The solvent should be inert,
i.e. it should
not chemically react with the components and should be removable during drying
after
coating. Suitable solvents are, for example, ketones, ethers and esters, such
as methyl ethyl
ketone, isobutyl methyl ketone, cyclopentanone, cyclohexanone, N-
methylpyrrolidone, di-
oxane, tetrahydrofuran, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-
propanol, 1,2-di-
methoxyethane, ethyl acetate, n-butyl acetate and ethyl 3-ethoxypropionate.
The formulation is uniformly applied to a substrate by known coating
processes, for example
centrifuging, dipping, knife application, curtain coating, brush application,
screen printing,
spraying, especially by electrostatic spraying and reverse roll coating.
The coating thickness and type of substrate depend on the desired field of
application, The
coating thickness is generally within the range from about 0.1 p.m to higher
than 100 p,m,
e.g. from 1 p.m to 30 Vim, preferably from 4 p.m to 20 Vim.
An other field in which the novel composition may be used is metal coating,
for example
coating metal sheets and tubes, tins or bottle caps. The metals to be coated
can be uncoat-
ed or precoated. Suitable substrates are especially metals, such as aluminium
or tinplate.
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The novel white compositions are distinguished by having very good resistance
to yellowing.
Another advantage is that the heavy metal anions normally used in the
technology, for exam-
ple SbFsanions, are not present in these compounds.
The novel formulations are cured by irradiation with light in the wavelength
of 200-600 nm.
Where necessary, the formulation can be subjected to a heat treatment after
irradiation. The
thermal aftertreatment is conveniently carried out in the temperature range
from 50-250°C,
e.g. from 100-220°C, preferably from 150-210°C.
Accordingly, this invention also relates to a process for the polymerisation
of compositions
described above, which comprises irradiating the composition with light in the
wavelength of
200-600 nm, and to a corresponding process in which the irradiation is
followed by a heat
treatment.
The UV irradiation for curing the novel formulation is usually carried out
using light in the
wavelength from 200-600 nm. Suitable radiation comprises, for example,
sunlight or light
from artificial light sources. A large number of widely different types of
light sources can be
used, including point sources and arrays of reflector lamps. Examples are:
carbon arc
lamps, xenon arc lamps, mercury medium, high and low pressure lamps which are
doped,
where required, with metal halides (metal halogen lamps), microwave-excited
metal vapour
lamps, excimer lamps, superactinic fluorescent tubes, fluorescent lamps, argon
glow lamps,
flash lamps, photographic floodlights, electron beams and X-rays. Examples of
suitable
lamps are fusion lamps, such as fusion H (main emissions: mercury medium
pressure spec-
trum), fusion D (main emissions: 350-450 nm), fusion V (main emissions: 400-
450 nm) or
fusion M (main emissions: 360-370 nm and 400-410 nm). The distance between
lamp and
substrate to be irradiated can vary depending on the purpose of application
and type or
strength of lamp, for example from 2 cm to 150 cm. Other suitable lamps are
laser light
sources, for example excimer laser. It is also possible to use lasers in the
visible range.
Irradiation using fusion lamps, e.g. fusion H, fusion D, fusion V or fusion M,
is particularly
interesting.
This invention also relates to the use of the above compositions and to a
process for the
preparation of coatings, paints, printing inks, powder coatings, laminating
adhesives, dental
compositions, in particular white enamel formulations.
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In another of its aspects, this invention relates to a coated substrate which
is coated on at
least one surface with one of the above compositions, and to a coated
substrate to which the
novel composition is applied at a coating thickness of at least 0.1-100 p.m,
e.g. 1-30 wm,
preferably 4-15 pm.
The following Examples illustrate the invention in more detail. As in the
remainder of the
description and in the patent claims, parts and percentages are by weight,
unless otherwise
stated. If alkyl radicals or alkoxy radicals containing more than three carbon
atoms are given
without their isomeric form, then they refer to the respective n-isomers.
Example 1: Preparation of p-isobutylphenylphenyl iodonium hexafluorophosphate
A 1.5 I flask, equipped with reflex condenser, thermometer, stirrer and
nitrogen inlet, is
charged with 400 g (1.24 mol) of (diacetoxyiodo)benzene in 800 ml of acetic
acid and, after
heating to 40°C, 365.6 g (1.92 mol) of p-toluenesulfonic acid are added
in portions over 3 h.
The reaction mixture is stirred overnight at 40°C, cooled to room
temperature and filtered.
The filter cake is washed with water and dried at 60°C under high
vacuum, giving 372.4 g of
hydroxy(tosyloxy)iodobenzene.
In a 750 ml flask, equipped with reflex condenser, thermometer, stirrer and
nitrogen inlet,
157 g (0.4 mol) of hydroxy(tosyloxy)iodobenzene and 67.15 g (0.5 mol) of
isobutylbenzene
are heated in a mixture of 12 ml of acetic acid and 40 ml of acetonitrile for
48 hours to 85°C.
After cooling the reaction mixture to room temperature, 500 ml of water are
added and the
mixture is extracted with dichloromethane. After drying the organic phases
with magnesium
sulfate and filtration, the solvent is removed under vacuum. A solid is
precipitated by treat-
ment with hexane. Filtration gives 131.2 g of 4-isobutylphenylphenyl iodonium
tosylate as a
beige solid.
In a 750 ml flask, equipped with reflex condenser, thermometer, stirrer and
nitrogen inlet,
40.7 g (80 mmol) of 4-isobutylphenylphenyl iodonium tosylate and 29.5 g (160
mmol) of
potassium hexafluorophosphate in 500 ml of acetone are refluxed overnight. The
cooled
suspension is filtered and the filtrate is concentrated under vacuum. 200 ml
of dichioro-
methane are added and the solution is washed with water. After drying over
magnesium
sulfate and filtration, the solvent is stripped off under vacuum, giving 36.5
g of p-isobutyl-
phenylphenyl iodonium hexafluorophosphate in the form of a colourless oil.
The'H-NMR
spectrum (measured in dimethyisulfoxide-dB) exhibits displacement signals at
the following
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values [ppm]: 8.22 (4H, m, ArH), 7.64 (1 H, m, ArH), 7.53 (2H, m, ArH), 7.34
(2H, m, ArH),
2.47 (2H, m, 2 CH2), 1.82 (1 H, m, CH(CH3)2), 0.82 (6H, d, J=6.2 Hz, 2 CH3).
Elemental analysis C,sH,eF6lP:
calculated C 39.86% H 3.76% F 23.64% I 26.32% P 6.42%
found C 40.14% H 3.89% F 23.63% I 26.20% P 6.28%
The compounds of the following Examples 2-6 are prepared in analogy to the
method of
Example 1 from the corresponding substituted aromatic compounds.
Example 2: (4-Hexylphenyl)phenyl iodonium hexafluorophosphate
Prepared from hexylbenzene. The title product is obtained as a brown oil.'H-
NMR measured
in CD3CN [ppmJ: 8.02 (4H, m, ArH), 7.71 (1 H, m, ArH), 7.53 (2H, m, ArH), 7.36
(m, 2H, ArH),
2.65 (2H,t, J=7.7 Hz, ArCHZ), 1.55 (2H, m, CH2), 1.28 (6H, m, (CH2)3), 0.85
(3H,t, J= 6.5Hz,
CH3). According to'H-NMR, the product contains about 8% of the 2-hexyl
isomeric product.
Example 3: (4-Octylphenyl)phenyl iodonium hexafluorophosphate
Prepared from octylbenzene. The title product is obtained as a reddish oil.'H-
NMR
measured in CD3CN [ppm]: 8.0 (4H, m, ArH), 7.70 (1 H, m, ArH), 7.52 (2H, m,
ArH), 7.36 (m,
2H, ArH), 2.65 (2H, t, J=7.7 Hz, ArCH2), 1.57 (2H, m, CH2), 1.25 (10H, m,
(CHZ)5), 0.85 (3H,
t, J= 6.5Hz, CH3). According to'H-NMR, the product contains about 8% of the 2-
octyl
isomeric product.
Example 4: (2,4-Dimethoxyphenyl)phenyl iodonium hexafluorophosphate
Prepared from 1,3-dimethoxybenzene. The title product is a solid having a
melting point from
129-130°C. ' H-NMR measured in DMSO-ds [ppmJ: 8.19 (1 H, d, J=8.8Hz
Hs), 8.07 (2H, m,
H2~6.), 7.63 (1 H, m, H4.), 7.49 (2H, m, H3~5~), 6.80 (1 H, m, H3), 6.69 (1 H,
dd, J=8.8 and 2.1 Hz,
H5), 3.94 (3H, s, OCH3), 3.83 (3H, s, OCH3).
Example 5: (2,4-Diethoxyphenyl)phenyl iodonium hexafluorophosphate
Prepared from 1,3-diethoxybenzene. The title product is a solid having a
melting point of
158°C. 'H-NMR measured in DMSO-ds [ppm]: 8.17 (1 H, d, J=8.8Hz Hs),
8.05 (2H, m, H2.6~),
7.64 (1 H, m, H4.), 7.50 (2H, m, H3~5~), 6.75 (1 H, m, H3), 6.66 (1 H,dd,
J=8.8 and 2.5Hz, HS),
4.14 (4H, m, 20CH2), i.33 (6H, m, 2CH3).
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Examale 6: (2,4-Diisopropoxyphenyi)phenyl iodonium hexafluorophosphate
Prepared from 1,3-diisopropoxybenzene. The title product is a solid having a
melting point of
125°C.'H-NMR measured in DMSO-ds [ppm]: 8.15 (1H, d, J=8.8Hz Hs), 8.03
(2H, m, H2~6.),
7.63 (1 H, m, H4~), 7.50 (2H, m, H3.5~), 6.73 (1 H, m, H3), 6.66 (1 H, dd,
J=8.8 and 2.2Hz, HS),
4.78 (2H, m, 20CH), 1.23 (12H, m, 4CH3).
Example 7: Preparation of bis(p-isobutylphenyl)iodonium hexafluorophosphate
In a 6 I flask, equipped with reflux condenser, thermometer, stirrer and
nitrogen inlet, 211.2 g
(1.57 mol) of isobutylbenzene and 140.3 g (0.65 mol) of potassium iodate are
cooled to 0°C
in a mixture of 1850 ml of acetic acid and 525 ml of acetic anhydride. A
mixture consisting of
385 ml of acetic acid and 310 ml of sulfuric acid is added dropwise. The
mixture is stirred
overnight at room temperature and 39.15 g of sodium bisulfate in 2000 ml of
water are add-
ed. The solution is extracted with hexane and dichloromethane. The organic
phases are
dried over magnesium sulfate and filtered and the solvent is stripped off
under vacuum,
giving 304.9 g of bis(4-isobutyfphenyl)iodonium bisulfate in the form of a
brown oil.
In a 1.5 I flask, equipped with reflux condenser, thermometer, stirrer and
nitrogen inlet, a
mixture consisting of 152.4 g (0.31 mol) of bis(4-isobutylphenyl)iodonium
bisulfate and
68.7 g (0.37 mol) of potassium hexafluorophosphate and 750 ml of water is
stirred for 5 h.
The solution is extracted with dichloromethane and the organic phases are then
washed with
water. Drying over magnesium sulfate, filtration and removal of the solvent by
evaporation
gives 107.4 g of bis(4-isobutylphenyl)iodonium hexafluorophosphate in the form
of a brown
resin. The'H-NMR spectrum (measured in CDCI3) exhibits displacement signals at
the
following values [ppm]: 7.85 (4H, m, ArH), 7.20 {4H, m, ArH), 2.42 (4H, d,
J=7.2 Hz, 2 CH2),
1.79 (2H, m, 2 CH(CH3)z), 0.82 (12H, d, J=6.6 Hz, 4 CH3).
The compounds of the following Examples 8-13 are prepared in analogy to the
methods of
Example 7 from the corresponding substituted aromatic compounds.
Example 8: Bis(4-butylphenyl)iodonium hexafluorophosphate
Prepared from n-butylbenzene. The title product is an orange resin. 'H-NMR
measured in
CD3CN [ppm]: 7.95 (4H, m, ArH), 7.35 {4H, m, ArH), 2.65 {4H,t, J=7.7 Hz, 2CH
2), 1.54 (4H,
m, 2CHz), 1.30 (4H, m, 2 CH2), 0.89 (6H, t, J=7.2 Hz, 2CH3).
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Example 9: Bis(4-hexyl-phenyl)iodonium hexafluorophosphate
This is a resin prepared from hexylbenzene.'H-NMR measured in CD3CN [ppm]:
7.94 (4H,
m, ArH), 7.34 (4H, m, ArH), 2.64 (4H, t, J=7.7 Hz, 2CH2), 1.56 (4H, m, 2CH2),
1.27 (12H, m,
6CH2), 0.85 (6H, t, J=6.5 Hz, 2CH3).
Example 10: Bis{4-octylphenyl)iodonium hexafluorophosphate
This is a resin prepared from octylbenzene.'H-NMR measured in CD3CN [ppm]:
7.95 (4H,
m, ArH), 7.34 (4H, m, ArH), 2.64 (4H, t, J=7.7 Hz, 2CH2), 1.56 {4H, m, 2CH2),
1.26 (20H, m,
lOCHz), 0.85 (6H, t, J=6.6 Hz, 2CH3).
Example 11: Bis(4-isopropylphenyl)iodonium hexafluorophosphate
Prepared from 4-isopropylphenol.'H-NMR signals measured in DMSO-ds [ppm]: 8.14
(4H,
m, ArH), 7.40 (4H, m, ArH), 2.92 (2H, sept, J=6.9Hz, 2CH), 1.16 (12H, d,
J=6.9Hz, 4CH3).
Example 12: Bis[4(1,1-dimethylprop-1-yl)phenyl]iodonium hexafluorophosphate
Prepared from 4(1,1-dimethylprop-1-yl)phenol. 'H-NMR signals measured in DMSO-
d~
[ppm]: 8.14 (4H, m, ArH), 7.48 (4H, m, ArH), 1.61 (4H, m, 2CH2), 1.21 (12H, s,
4CH3),
0.56 (6H, m, 2CH3).
Example 13: Bis(4-C3-C,4alkylphenyl)iodonium hexafluorophosphate
Prepared from a mixture of phenols substituted in 4-position by Ce-C,~alkyl.'H-
NMR signals
measured in CDCI3 [ppm]: 7.88 (4H, m, ArH), 7.30 (4H, m, ArH), 2.80-2.35 (=2H,
m), 1.75-
1.35 (=12H, m), 1.35-0.65 (=30H, m).
Example 14: Preparation of p-butoxyphenylphenyl iodonium hexafluorophosphate
A 350 ml flask, equipped with reflux condenser, thermometer, stirrer and argon
inlet, is
charged with 100 g (0.31 mol) of diacetoxyiodobenzene in 200 ml of acetic
acid, to which,
after heating to 40°C, 45.8 g (0.48 mol) of p-toluenesulfonic acid are
added in portions over
3h. The reaction solution is stirred overnight at 40°C, cooled to room
temperature and fil-
tered. The filter cake is washed with water and dried at 60°C under
vacuum, giving 71.2 g of
hydroxy(tosyloxy)iodobenzene.
In a 200 ml flask, equipped with reflux condenser, thermometer, stirrer and
argon inlet,
14.1 g (0.036 mol) of hydroxy(tosyloxy)iodobenzene and 5.1 g (0.034 mol) of 4-
butoxyben-
zene are heated for 2h to 40°C in a mixture consisting of 5 ml of
acetonitrile and 2 ml of
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acetic acid. After cooling the reaction mixture to room temperature, 100 ml of
water are
added and the mixture is extracted with methylene chloride. The organic phases
are dried
over magnesium sulfate, filtered and concentrated in a rotary evaporator. A
solid is preci-
pitated by treatment with hexane. Filtration gives 17.0 g of p-
butoxyphenylphenyl iodonium
tosylate in the form of a beige solid having a melting point of 169-171
°C.
In a 200 ml flask, equipped with reflux condenser, thermometer, stirrer and
argon inlet,
17.0 g (0.032 mol) of butoxyphenylphenyl iodonium tosylate and 6.6 g (0.036
mol) of po-
tassium hexafluorophosphate are stirred overnight in 50 ml of acetone at room
temperature.
The resulting suspension is filtered and the filtrate is concentrated in a
rotary evaporator.
50 ml of methylene chloride are added and the solution is washed with water.
After drying
over magnesium sulfate and filtration, the solvent is stripped off under
vacuum. A solid is
precipitated by treatment with hexane. Filtration gives 15.0 g of p-
butoxyphenylphenyl iodo-
nium hexafluorophosphate in the form of a beige solid having a melting point
of 101-103°C.
Elemental analysis:
calculated C 38.56% H 3.64% F 22.88% P 6.22% J 25.47%
found C 39.84% H 3.72% F 21.61 % P 6.18% J 25.32%
Examples 15-16:
The compounds of Examples 15-16 are prepared in analogy to the method of
Example 14,
using the corresponding educts. The compounds and their physical data are
listed in the
foNowing Table 1.
Table 1: ~ ~ I+-~-~-O-R PFs
Example R Melting pointElemental analysis
[%]
calculated found
C: 38.56 39.84
H: 03.64 03.72
15 2-methylpropylresin F: 22.88 21.61
P: 06.22 08.18
I: 25.47 25.32
C: 47.23 48.60
H: 05.70 05.61
16 dodecyl 87 - 89 C F: 17.04 18.67
P: 04.82 05.07
I: 20.71 20.79
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Example 17:
A white enamel formulation is prepared by mixing the following components:
35.3 % of diglycidyi ether of bisphenol A (ARALDIT GY 250, Ciba
Spezialitatenchemie,
Switzerland),
14.1 % of trimethylolpropane triglycidyl ether,
9.4 % of C,v,4alkyl glycidyl ether,
39.2 % of rutile titanium dioxide (R-TC2, Tioxide, UK),
1.5 % of p-isobutylphenylphenyl iodonium hexafluorophosphate (see Example 1 ),
0.5 % of isopropylthioxanthone.
The mixture is heated to 60°C and shaken for 6 minutes. After heating
it once more to 60°C
and shaking it for another 6 minutes, it is stirred for 30 minutes at
60°C. The formulation is
applied to a 300 p.m aluminium sheet using a 12 um spiral applicator.
Irradiation is carried
out using a UV processor under two 80 W/cm mercury medium pressure lamps. The
highest
belt speed is determined at which the sample is cured with the surface still
remaining tack-
free. The higher the belt speed, the more reactive the formulation. Moreover,
immediately
after irradiation and also after subjecting the sample to a final heat
treatment for 5 minutes at
180°C in a circulating air oven, the yellowing of the coating is
determined via the Yellowness
Index (YI) in accordance with ASTMD-1925-70. The lower the YI value, the less
yellowing of
the coating.
This formulation is cured tack-free at a belt speed of 12.5 m/min. Immediately
after irradia-
tion, the measured Yl value is -2.5, and after the subsequent heat treatment
it is -3.4.
Example 18
A white enamel formulation is prepared by mixing the following components:
17.0 parts of diglycidyl ether of bisphenol A (ARALDIT GY 250, of Ciba
Spezialitatenchemie,
Switzerland),
17.0 parts of trimethylolpropane triglycidyl ether,
13.0 parts of C,z,4alkyl glycidyl ether,
50.0 parts of rutile titanium dioxide (R-TC2, Tioxide, UK),
2.0 parts of p-isobutylphenylphenyl iodonium hexafluorophosphate (see Example
1 ),
1.0 parts of isopropylthioxanthone
2.0 parts of dispersant (Disperbyk 110; Byk Chemie, Germany)
0.5 parts of wax (polyfluo 540).
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The mixture is heated to 60°C and shaken for 6 minutes. After heating
it once more to 60°C
and shaking it for another 6 minutes, it is stirred for 30 min utes at
60°C. The formulation is
applied to 300 p.m aluminium sheets using a 12 ~m spiral applicator.
Irradiation is carried out
using a UV processor under a 120W/cm microwave-excited M-Fusion lamp (of
Fusion UV
Systems) by passing the sample to be cured on a belt under the lamps. The
highest belt
speed is determined at which the sample is cured with the surface still
remaining tack-free.
At a belt speed of 10 m/min, the sample is cured with a tack-free surface.
