U.S. patent application number 09/775767 was filed with the patent office on 2001-08-23 for radiation-curing compositions.
This patent application is currently assigned to Wacker-Chemie GmbH. Invention is credited to Dauth, Jochen, Herzig, Christian, Wolferseder, Josef, Zoellner, Oliver.
Application Number | 20010016640 09/775767 |
Document ID | / |
Family ID | 27216934 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010016640 |
Kind Code |
A1 |
Dauth, Jochen ; et
al. |
August 23, 2001 |
Radiation-curing compositions
Abstract
Radiation-curable compositions containing linear
organopolysiloxanes bearing (meth)acryloxy groups and a
photosensitizer are useful for release coatings particularly
release coatings with enhanced adhesion to the substrate onto which
they are coated, for example those used for adhesives such as
pressure sensitive adhesive labels.
Inventors: |
Dauth, Jochen; (Burghausen,
DE) ; Herzig, Christian; (Waging am See, DE) ;
Wolferseder, Josef; (Tann, DE) ; Zoellner,
Oliver; (Simbach am Inn, DE) |
Correspondence
Address: |
William G. Conger
Brooks & Kushman P.C.
1000 Town Center, 22nd Floor
Southfield
MI
48075-1351
US
|
Assignee: |
Wacker-Chemie GmbH
Munchen
DE
|
Family ID: |
27216934 |
Appl. No.: |
09/775767 |
Filed: |
February 2, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09775767 |
Feb 2, 2001 |
|
|
|
09319905 |
Aug 20, 1999 |
|
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Current U.S.
Class: |
528/26 |
Current CPC
Class: |
C09D 183/14 20130101;
C08L 2666/28 20130101; C08L 2666/28 20130101; C09D 183/14 20130101;
C09D 183/06 20130101; C09D 183/06 20130101 |
Class at
Publication: |
528/26 |
International
Class: |
C08G 077/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 1996 |
DE |
196 52 304.4 |
May 15, 1997 |
DE |
197 20 472.4 |
Claims
1. Radiation-curing compositions comprising (A) linear
organopolysiloxanes containing (meth)acryloxy groups, of the
general formula
R.sup.1.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--SiR.sub.2O(R.su-
b.2SiO).sub.c].sub.dSiR.sub.3-bR.sup.1.sub.b (I) in which R can be
identical or different and is a monovalent, substituted or
unsubstituted hydrocarbon radical having 1 to 18 carbon atoms per
radical, which is free from terminal aliphatic carbon-carbon
multiple bonds, R.sup.1 is a radical of the formula 5 where z is an
integer whose value is from 1 to 10, R.sup.2 is a hydrogen atom or
a methyl radical, R.sup.3 is a linear or branched alkylene radical
having 1 to 6 carbon atom(s) per radical, and R.sup.4 is a linear
or branched alkylene radical having 1 to 6 carbon atom(s) per
radical, Y is a divalent organic radical which is free from
terminal aliphatic carbon-carbon multiple bonds, a is 0 or 1, b is
0 or 1, with the proviso that the sum a+b per molecule is 1 or 2,
on average from 1.3 to 1.9, c is an integer whose value is from 1
to 1000, and d is 0 or an integer whose value is from 1 to 10, and
(B) photosensitizers.
2. Radiation-curing compositions according to claim 1,
characterized in that R.sup.1 is a radical of the formula 6where z
is an integer whose value is from 1 to 10.
3. Radiation-curing compositions according to claim 1 or 2,
characterized in that d is 0.
4. Process for preparing coatings which repel tacky substances by
applying a crosslinkable composition comprising (A) linear
organopolysiloxanes containing (meth)acryloxy groups, of the
general formula
R.sup.1.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--SiR.sub.2O(R.su-
b.2SiO).sub.c].sub.dSiR.sub.3-bR.sup.1.sub.b (I) where R, R.sup.1,
Y, a, b, c and d are as defined in claim 1, with the proviso that
the sum a+b per molecule is 1 or 2, on average from 1.3 to 1.9, and
(B) photosensitizers to the surfaces which are to be made repellent
to tacky substances, and then curing the crosslinkable composition
by irradiation.
5. Linear organopolysiloxanes containing (meth)acryloxy groups, of
the general formula
R.sup.1.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--
-SiR.sub.2O(R.sub.2SiO).sub.c].sub.dSiR.sub.3-bR.sup.1.sub.b (I)
where R, R.sup.1, Y, a, b, c and d are as defined in claim 1, with
the proviso that the sum a+b per molecule is 1 or 2, on average
from 1.3 to 1.9.
6. Photosensitizer-comprising mixture comprising from 10 to 40% by
weight of
oligo[2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone] and
from 90 to 60% by weight of an organopolysiloxane containing
(meth)acryloxy groups, of the general formula
R.sup.1R.sub.2SiO(R.sub.2Si- O).sub.nSiR.sub.2R.sup.1 (III) where R
and R.sup.1 are as defined in claim 1 and n is an integer from 5 to
30.
7. Photosensitizer mixture according to claim 6, characterized in
that R.sup.1 is as defined in claim 2.
8. Radiation-curing composition according to claim 1, 2 or 3,
characterized in that a mixture according to claim 6 or 7 is used
in amounts of from 5 to 30% by weight, based on the component (A),
as photosensitizer (B).
Description
[0001] The invention relates to radiation-curing compositions
comprising
[0002] (A) organopolysiloxanes containing (meth)acryloxy groups,
and
[0003] (B) photosensitizers,
[0004] and to their use for preparing coatings which repel tacky
substances.
[0005] EP-A 624 627 (Shin-Etsu Chemical Co., Ltd; published on Nov.
17, 1994) describes radiation-curing organopolysiloxane mixtures
which comprise .omega.-(meth)acryloxyalkyl groups. The
organopolysiloxanes present in the mixtures are branched, with the
branching sites representing trifunctional monoorganosiloxy groups,
known as T units.
[0006] U.S. Pat. No. 5,034,419 (Th. Goldschmidt; published on Jul.
23, 1991) describes (meth)acrylate-modified organopolysiloxane
mixtures for preparing abhesive coating materials, where two
organopolysiloxanes differing in chain length are mixed in
different proportions by weight.
[0007] WO95/26266 (Mobil Oil Corporation; published on Oct. 5,
1995) describes abhesive coating materials comprising added
monomeric or oligomeric organic acrylate esters.
[0008] DE-A 44 43 749 (Wacker Chemie GmbH; published on Jun. 13,
1996) discloses organopolysiloxanes containing (meth)acryloxy
groups.
[0009] One object was to provide novel compositions based on
organopolysiloxanes containing (meth)acryloxy groups which undergo
free-radical crosslinking by irradiation, preferably with light.
Another object was to provide novel compositions for the
preparation of coatings which repel tacky substances. A further
object was to provide abhesive coating compositions which give
abrasion-resistant coatings, i.e. which adhere to the substrate so
that they cannot be separated from the substrate by mechanical
influences, for example by rubbing, in order that they are not
partially detached, and so reduce the adhesive force of the labels,
when carriers located on them which are provided with adhesive,
such as labels, for example, are peeled off. Yet another object was
to provide abhesive coating compositions which give tack-free,
thoroughly cured coatings. These objects are achieved by the
invention.
[0010] The invention provides radiation-curing compositions
comprising
[0011] (A) linear organopolysiloxanes containing (meth)acryloxy
groups, of the general formula
R.sup.1.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--SiR.sub.2O(R.sub-
.2SiO).sub.c].sub.dSiR.sub.3-bR.sup.1.sub.b (I)
[0012] in which R can be identical or different and is a
monovalent, substituted or unsubstituted hydrocarbon radical having
1 to 18 carbon atoms per radical, which is free from terminal
aliphatic carbon-carbon multiple bonds,
[0013] R.sup.1 is a radical of the formula 1
[0014] where z is an integer whose value is from 1 to 10,
[0015] R.sup.2 is a hydrogen atom or a methyl radical,
[0016] R.sup.3 is a linear or branched alkylene radical having 1 to
6 carbon atom(s) per radical, and
[0017] R.sup.4 is a linear or branched alkylene radical having 1 to
6 carbon atom(s) per radical,
[0018] Y is a divalent organic radical which is free from terminal
aliphatic carbon-carbon multiple bonds,
[0019] a is 0 or 1,
[0020] b is 0 or 1,
[0021] with the proviso that the sum a+b per molecule is 1 or 2, on
average from 1.3 to 1.9,
[0022] c is an integer whose value is from 1 to 1000, and
[0023] d is 0 or an integer whose value is from 1 to 10, and
[0024] (B) photosensitizers.
[0025] The invention additionally provides a process for preparing
coatings which repel tacky substances by applying crosslinkable
compositions comprising
[0026] (A) linear organopolysiloxanes containing (meth)acryloxy
groups, of the general formula
R.sup.1.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--SiR.sub.2O(R.sub-
.2SiO).sub.c].sub.dSiR.sub.3-bR.sup.1.sub.b (I)
[0027] where R, R.sup.1, Y, a, b, c and d are as defined above,
[0028] with the proviso that the sum a+b per molecule is 1 or 2, on
average from 1.3 to 1.9, and
[0029] (B) photosensitizers
[0030] to the surfaces which are to be made repellent to tacky
substances, and then curing the crosslinkable composition by
irradiation.
[0031] The invention also provides linear organopolysiloxanes
containing (meth)acryloxy groups, of the general formula
R.sup.1.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--SiR.sub.2O(R.sub-
.2SiO).sub.c].sub.dSiR.sub.3-bR.sup.1.sub.b (I)
[0032] where R, R.sup.1, Y, a, b, c and d are as defined above,
[0033] with the proviso that the sum a+b per molecule is 1 or 2, on
average from 1.3 to 1.9.
[0034] The invention also provides organopolysiloxanes containing
Si-bonded hydrogen atoms, of the general formula
H.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--SiR.sub.2O(R.sub.2SiO)-
.sub.c].sub.dSiR.sub.3-bH.sub.b (II)
[0035] where R, Y, a, b, c and d are as defined above,
[0036] with the proviso that the sum a+b per molecule is 1 or 2, on
average from 1.3 to 1.9.
[0037] The novel organopolysiloxanes (A) preferably have a
viscosity of from 20 to 20,000 mm.sup.2/s at 25.degree. C.,
particularly preferably from 20 to 1000 mm.sup.2/s at 25.degree. C.
and, with very particular preference, from 20 to 500 mm.sup.2/s at
25.degree. C.
[0038] The novel organopolysiloxanes preferably have iodine numbers
of between 1 and 60, preferably between 4 and 40, the iodine number
indicating the amount of iodine, in grams per 100 grams of novel
organopolysiloxane employed, which is consumed during addition onto
the double bond.
[0039] Examples of the radical R are in each case alkyl radicals,
such as the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,
tert-butyl, n-pentyl, isopentyl, neopentyl, and the tert-pentyl
radical, hexyl radicals, such as the n-hexyl radical, heptyl
radicals, such as the n-heptyl radical, octyl radicals, such as the
n-octyl radical and isooctyl radicals, such as the
2,2,4-trimethylpentyl and the 2-ethylhexyl radical, nonyl radicals,
such as the n-nonyl radical, decyl radicals, such as the n-decyl
radical, dodecyl radicals, such as the n-dodecyl radical,
tetradecyl radicals, such as the n-tetradecyl radical, hexdecyl
radicals, such as the n-hexadecyl radical, and octadecyl radicals,
such as the n-octadecyl radical, cylcoalkyl radicals, such as
cyclopentyl, cyclohexyl and 4-ethylcyclohexyl radical, cycloheptyl
radicals, norbornyl radicals and methylcyclohexyl radicals, aryl
radicals, such as the phenyl, biphenyl [sic], naphthyl and anthryl
and phenanthryl radical; alkaryl radicals, such as o-, m-, p-tolyl
radicals, xylyl radicals and ethylphenyl radicals; aralkyl
radicals, such as the benzyl radical, and also the .alpha.- and the
.beta.-phenylethyl radical. The radical R is preferably the methyl
radical.
[0040] Examples of substituted radicals R are haloalkyl radicals,
such as the 3,3,3-trifluoro-n-propyl radical, the
2,2,2,2',2',2'-hexafluoroisopro- pyl radical and the
heptafluoroisopropyl radical, haloaryl radicals, such as the o-, m-
and p-chlorophenyl radical, and alkyl radicals which are
substituted by an ether oxygen atom, such as the 2-methoxyethyl and
the 2-ethoxyethyl radical.
[0041] The radical R.sup.2 is preferably a hydrogen atom.
[0042] Examples of radicals R.sup.3 are alkylene radicals of the
formula --CH.sub.2--CH.sub.2--, --CH.sub.2--CH.sub.2--CH.sub.2--,
--C(CH.sub.3)HCH.sub.2-- and --(CH.sub.2).sub.4--. R.sup.3 is
preferably a radical of the formula --CH.sub.2--CH.sub.2--.
[0043] Examples of alkylene radicals R.sup.4 are those of the
formula --CH.sub.2--, --CH(CH.sub.3)--, --C(CH.sub.3).sub.2--,
--C(CH.sub.3)(C.sub.2H.sub.5)--, --(CH.sub.2).sub.2-- and
--(CH.sub.2).sub.4--, preference being given to the radical of the
formula --CH.sub.2--.
[0044] Examples of radicals R.sup.1 are those of the formula 2
[0045] where z is as defined above and is preferably an integer
having a value from 2 to 8.
[0046] Y is preferably a divalent hydrocarbon radical which can be
interrupted by one or more oxygen atoms. Examples of radicals Y are
those of the formula --CH.sub.2CH.sub.2--, --CH(CH.sub.3)--,
--(CH.sub.2).sub.4--, --(CH.sub.2).sub.5--, --(CH.sub.2).sub.6--,
--(CH.sub.2).sub.8--, --(CH.sub.2).sub.10--, --(CH.sub.2).sub.12--,
--(CH.sub.2).sub.3O(CH.sub.2).sub.3--,
1,3-(CH.sub.2CH.sub.2).sub.2(C.sub- .6H.sub.4),
1,4-(CH.sub.2CH.sub.2).sub.2(C.sub.6H.sub.4),
1,3-(CH.sub.2CHCH.sub.3).sub.2(C.sub.6H.sub.4) and
1,4-(CH.sub.2CHCH.sub.3).sub.2(C.sub.6H.sub.4), preference being
given to the radicals of the formula --CH.sub.2CH.sub.2--,
--CH(CH.sub.3)--, --(CH.sub.2).sub.6--, --(CH.sub.2).sub.8--,
1,3-(CH.sub.2CH.sub.2).sub.2(- C.sub.6H.sub.4),
1,4-(CH.sub.2CH.sub.2).sub.2(C.sub.6H.sub.4),
1,3-(CH.sub.2CHCH.sub.3).sub.2(C.sub.6H.sub.4) and
1,4-(CH.sub.2CHCH.sub.3).sub.2(C.sub.6H.sub.4) and particular
preference to the radical of the formula --CH.sub.2CH.sub.2--.
[0047] The sum a+b is preferably on average from 1.4 to 1.9.
[0048] As end groups the organopolysiloxanes (A) contain on average
from 65 to 95 mol-% of radicals R.sup.1 (or, respectively, from 35
to 5 mol-% of radicals R, preferably methyl end groups),
corresponding to an average sum a+b of from 1.3 to 1.9. In the case
of the novel compositions it is preferred to employ a mixture of
different organopolysiloxanes (A).
[0049] Preferably, c is an integer whose value is from 10 to 300,
more preferably from 15 to 150.
[0050] Preferably, d is 0 or an integer whose value is from 1 to 3;
d is more preferably 0.
[0051] The novel, linear organopolysiloxanes containing
(meth)acryloxy groups are preferably prepared by reacting
alkoxylated alk-2-yne 1,4-di(meth)acrylates (1) of the general
formula 3
[0052] where R.sup.2, R.sup.3, R.sup.4 and z are as defined
above,
[0053] with organopolysiloxanes (2) containing Si-bonded hydrogen
atoms, of the general formula
H.sub.aR.sub.3-aSiO(R.sub.2SiO).sub.c[R.sub.2Si--Y--SiR.sub.2O(R.sub.2SiO)-
.sub.c].sub.dSiR.sub.3-bH.sub.b (II)
[0054] where R, Y, a, b, c and d are as defined above,
[0055] in the presence of catalysts (3) which promote the addition
of Si-bonded hydrogen onto aliphatic multiple bond
[0056] and in the presence of polymerization inhibitors (4),
[0057] with the proviso that alkoxylated alk-2-yne
1,4-di(meth)acrylates (1) are employed in amounts of from 1.01 to
1.5 mol, preferably from 1.01 to 1.2 mol, per gram atom of
Si-bonded hydrogen in organopolysiloxanes (2).
[0058] Alkoxylated alk-2-yne 1,4-di(meth)acrylates (1) can be
prepared by general methods from the prior art; in such methods,
the alkoxylated alkynediol, for example ethoxylated
but-2-yne-1,4-diol, is esterified with acrylic acid under acidic
catalysis. The water of reaction is removed azeotropically.
[0059] Catalysts (3) which promote the addition of Si-bonded
hydrogen onto aliphatic multiple bond, known as hydrosilylation
catalysts, are familiar to the skilled worker, and examples
thereof, and also the amounts of catalysts employed, are described
in DE-A 44 43 749.
[0060] As polymerization inhibitor (4) it is preferred to employ
phenolic stabilizers, such as cresol derivatives or hydroquinone
derivatives, for example bis(tert-butyl)cresol,
2,5-di-tert-butylhydroquinone or the monomethyl ether of
hydroquinone, or phenothiazine, in a concentration of from 0.001 to
1% by weight, preferably from 0.002 to 0.5% by weight, based on the
overall weight of alkoxylated alkyne diacrylate (1) and
organopolysiloxane (2).
[0061] Preference is given to organopolysiloxanes, containing
(meth)acryloxy groups, of the formula (I) where d is 0. In
preparing these organopolysiloxanes of the formula (I) where d is
0, it is preferred to employ organopolysiloxanes, containing
Si-bonded hydrogen atoms, of the formula (II) where d is 0. A
preferred process for preparing the organopolysiloxanes of the
formula (II) where d is 0 is the acid-catalysed equilibration of
polydialkylsiloxanes having alkyl end groups with
polydialkylsiloxanes having terminal Si-bonded hydrogen atoms.
[0062] The novel organopolysiloxanes containing (meth)acryloxy
groups are preferably crosslinked by light, more preferably by
ultraviolet light, with preference being given to that having
wavelengths in the range from 200 to 400 nm. The ultraviolet light
can be generated, for example, in xenon lamps, in low-, medium- or
high-pressure mercury lamps or in excimer lamps. Also suitable for
photocrosslinking is light having a wavelength of from 400 to 600
nm, i.e. so-called halogen light.
[0063] Alternatively, the energy sources suitable for crosslinking
the novel organopolysiloxanes can be X-rays, gamma rays or electron
beams or can involve the simultaneous use of at least two different
kinds of such radiations. In addition to the high-energy radiation
it is also possible to employ a supply of heat, including heat
supplied by means of infrared light. Supplying such heat is,
however, in no way necessary and is preferably omitted in order to
reduce the energy cost.
[0064] Suitable photosensitizers (B) are substituted or
unsubstituted acetophenones, propiophenones, benzophenones,
anthraquinones, benzils, carbazoles, xanthones, thioxanthones,
fluorenes, fluorenones, benzoins, naphthalenesulfonic acids,
benzaldehydes and cinnamic acids.
[0065] Examples of photosensitizers (B) are fluorenone, fluorene,
carbazole; acetophenone; substituted acetophenones such as
3-methylacetophenone, 2,2'-dimethoxy-2-phenylacetophenone,
4-methylacetophenone, 3-bromoacetophenone, 4-allylacetophenone,
p-diacetylbenzene, p-tert-butyltrichloroacetophenone;
propiophenone; substituted propiophenones such as
1-[4-(methylthio)phenyl]-2-morpholinyl- propan-1-one, benzophenone;
substituted benzophenones such as Michler's ketone,
3-methoxybenzophenone, 4,4'-dimethylaminobenzophenone,
4-methylbenzophenone, 4-chlorobenzophenone,
4,4'-dimethoxybenzophenone, 4-chloro-4'-benzylbenzophenone;
xanthone; substituted xanthone such as 3-chloroxanthone,
3,9-dichloroxanthone, 3-chloro-8-nonylxanthone; thioxanthone,
substituted thioxanthones such as isopropylthioxanthones;
anthraquinone; substituted anthraquinones such as
chloroanthraquinone and anthraquinone-1,5-disulfonic acid disodium
salt; benzoin; substituted benzoins, such as benzoin methyl ether;
benzil; 2-naphthalenesulfonyl chloride; benzaldehyde; cinnamic
acid; and oligo[2-hydroxy-2-methyl-1-(4--
(1-methylvinyl)phenyl)propanone].
[0066] Photosensitizers (B) are employed in the novel compositions
in amounts of preferably from 0.01 to 10% by weight, more
preferably from 0.5 to 5 percent by weight, based in each case on
the overall weight of the organopolysiloxanes (A) to be
crosslinked.
[0067] The preferred photosensitizer (B) used is
oligo[2-hydroxy-2-methyl-- 1-(4-(1-methylvinyl)phenyl)propanone],
obtainable commercially under the trade name "ESACURE-KIP 150" from
Lamberti. In this context, the oligomeric photosensitizer is
preferably dissolved in a short-chain organopolysiloxane.
[0068] Particular preference is given to mixtures comprising
[0069] from 10 to 40% by weight, in particular 20% by weight, of
oligo[2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone]
and
[0070] from 90 to 60% by weight, in particular 80% by weight, of an
organopolysiloxane containing (meth)acryloxy groups, of the general
formula
R.sup.1R.sub.2SiO(R.sub.2SiO).sub.nSiR.sub.2R.sup.1 (III)
[0071] where R and R.sup.1 are as defined above and n is an integer
from 5 to 30, in particular 13, for use as photosensitizer.
[0072] The photosensitizer mixture is employed in the novel
radiation-curing compositions preferably in amounts of from 5 to
30% by weight, based on the component (A).
[0073] The use of the photosensitizer mixture in the novel
radiation-curing compositions has the advantage that the formation
of benzaldehyde as an elimination product in the course of curing
is avoided and that substrate adhesion and the abrasion resistance
of the coatings are improved.
[0074] The novel compositions may comprise polymerization
inhibitors. For reasons of better handling it is preferred to add
small amounts of inhibitors (C) to the novel compositions in order,
for example, to prevent premature crosslinking of a servicable
formulation in the course of its storage. Examples of inhibitors
which may be employed are all customary inhibitors which have also
been employed to date in free-radical processes, such as
hydroquinone, 4-methoxyphenol, 2,6-di-tert-butyl-4-methylphenol or
phenothiazine. Inhibitors are preferably employed in amounts of
from 10 to 10,000 ppm, particularly preferably from 50 to 1000 ppm,
based in each case on the overall weight of the organopolysiloxanes
(A) to be crosslinked.
[0075] If desired, it is possible in addition to add monomeric or
oligomeric, organic (meth)acrylate esters or mixtures thereof in an
amount of preferably from 0.1 to 10 percent by weight, based on the
overall weight of the organopolysiloxanes (A) to be crosslinked,
but this is not preferred.
[0076] Examples of surfaces to which the novel coatings can be
applied are those of paper, wood, cork, polymer films, for example
polyethylene films or polypropylene films, ceramic articles, glass,
including glass fibers, metals, boards, including those of
asbestos, and woven and nonwoven textile comprising natural or
synthetic organic fibers. The novel coatings are used, for example,
in the coating of release papers.
[0077] The application of the novel, photocrosslinkable
compositions to the surfaces that are to be coated can be made by
any of the appropriate and widely known methods of preparing
coatings from liquid materials, for example by dipping, spreading,
flowcoating, spraying, rolling, printing, by means for example of
an offset gravure coating device, or by blade or knife coating.
[0078] The novel radiation-curing coatings have the advantage that
with respect to numerous tacky substances there is no zippy
release. A further advantage is that the novel compositions possess
low viscosities and do not give rise to any misting problems even
under high friction. The novel compositions exhibit good flow on
numerous substrates. Furthermore, there is the advantage that,
owing to the specifically adjustable functional densities, a
variety of graduations in release force can be established and the
compositions are readily blendable with one another.
[0079] Preparing the Organopolysiloxanes (A):
[0080] a) 80 g of an .alpha.,.omega.-dihydridodimethylpolysiloxane
(content of Si-bonded hydrogen: 0.346% by weight) having a
viscosity of 3.7 mm.sup.2/s at 25.degree. C. and 423.9 g of a
methyl-terminated polydimethylsiloxane with a mean chain length of
about 390 siloxy units and a viscosity of 5000 mm.sup.2/s at
25.degree. C. are equilibrated with PNCl.sub.2 catalysis (40 ppm)
at 140.degree. C. under nitrogen and with stirring for two hours.
After cooling to 70.degree. C., 5.2 g of magnesium oxide are added
to the reaction mixture, which is finally brought to room
temperature with stirring. After filtration, the product is heated
to constant weight over forty minutes at 120.degree. C. under a
high vacuum (1 mbar). This gives 474.5 g (92.5% of theory) of a
clear, colorless oil having a viscosity of 69 mm.sup.2/s at
25.degree. C. and a content of Si-bonded hydrogen of 0.044% by
weight (VSI). The polymer contains on average 88 mol-% of
hydridodimethylsiloxy groups.
[0081] 20 g of VSI, 4.04 g of an ethoxylated butinediol diacrylate
having a molecular weight of about 440 g/mol (9.2 mmol of C.dbd.C),
300 ppm of hydroquinone monomethyl ether based on the mass of
diacrylate and 16 g of toluene are thermally conditioned to
120.degree. C. with stirring. Then 48.1 mg of a 1% strength by
weight (based on elemental platinum) solution, in toluene, of a
tris(divinyltetramethyldisiloxane)diplatinum complex are added and
the reaction mixture is stirred at 120.degree. C. for twenty
minutes. After filtration, the product is heated to constant weight
for fifteen minutes at 100.degree. C. under a high vacuum (1 mbar).
This gives 23.6 g (98% of theory) of a clear, yellow oil having a
viscosity of 290 mm.sup.2/s at 25.degree. C. and an iodine number
of 18.7 g of iodine per 100 g of oil.
[0082] b) 50 g of an .alpha.,.omega.-dihydridodimethylpolysiloxane
(content of Si-bonded hydrogen: 0.346% by weight) having a
viscosity of 3.7 mm.sup.2/s at 25.degree. C. and 429.3 g of a
methyl-terminated polydimethylsiloxane with a mean chain length of
about 390 siloxy units and a viscosity of 5000 mm.sup.2/s at
25.degree. C. are equilibrated with PNCl.sub.2 catalysis (40 ppm)
at 140.degree. C. under nitrogen and with stirring for two hours.
After cooling to 70.degree. C., 4.8 g of magnesium oxide are added
to the reaction mixture, which is finally brought to room
temperature with stirring. After filtration, the product is heated
to constant weight over forty minutes at 120.degree. C. under a
high vacuum (1 mbar). This gives 451.5 g (94.2% of theory) of a
clear, colorless oil having a viscosity of 179 mm.sup.2/s at
25.degree. C. and a content of Si-bonded hydrogen of 0.028% by
weight (VSII). The polymer contains on average 82 mol-% of
hydridodimethylsiloxy groups.
[0083] 20 g of VSII, 2.57 g of an ethoxylated butinediol diacrylate
having a molecular weight of about 440 g/mol (5.9 mmol of C.dbd.C),
300 ppm of hydroquinone monomethyl ether based on the mass of
diacrylate and 10 g of toluene are thermally conditioned to
120.degree. C. with stirring. Then 45.1 mg of a 1% strength by
weight (based on elemental platinum) solution, in toluene, of a
tris(divinyltetramethyldisiloxane)di- platinum complex are added
and the reaction mixture is stirred at 120.degree. C. for twenty
minutes. After filtration, the product is heated to constant weight
for fifteen minutes at 100.degree. C. under a high vacuum (1 mbar).
This gives 21.8 g (97% of theory) of a clear, yellow oil having a
viscosity of 520 mm.sup.2/s at 25.degree. C. and an iodine number
of 12.5 g of iodine per 100 g of oil.
[0084] c) 400 g of an .alpha.,.omega.-dihydridodimethylpolysiloxane
(content of Si-bonded hydrogen: 0.049% by weight) having a
viscosity of 53 mm.sup.2/s at 25.degree. C. and 100 g of a
methyl-terminated polydimethylsiloxane with a mean chain length of
about 120 siloxy units and a viscosity of 250 mm.sup.2/s at
25.degree. C. are equilibrated with PNCl.sub.2 catalysis (40 ppm)
at 140.degree. C. under nitrogen and with stirring for two hours.
After cooling to 70.degree. C., 5 g of magnesium oxide are added to
the reaction mixture, which is finally brought to room temperature
with stirring. After filtration, the product is heated to constant
weight over forty minutes at 120.degree. C. under a high vacuum (1
mbar). This gives 420 g (84% of theory) of a clear, colorless oil
having a viscosity of 73 mm.sup.2/s at 25.degree. C. and a content
of Si-bonded hydrogen of 0.046% by weight (VSIII). The polymer
contains on average 86 mol-% of hydridodimethylsiloxy groups.
[0085] 20 g of VSIII, 4.19 g of an ethoxylated butinediol
diacrylate having a molecular weight of about 440 g/mol (9.6 mmol
of C.dbd.C), 300 ppm of hydroquinone monomethyl ether based on the
mass of diacrylate and 16.8 g of toluene are thermally conditioned
to 120.degree. C. with stirring. Then 52.3 mg of a 1% strength by
weight (based on elemental platinum) solution, in toluene, of a
tris(divinyltetramethyldisiloxane)di- platinum complex are added
and the reaction mixture is stirred at 120.degree. C. for twenty
minutes. After filtration, the product is heated to constant weight
for fifteen minutes at 100.degree. C. under a high vacuum (1 mbar).
This gives 22.3 g (92% of theory) of a clear, yellow oil having a
viscosity of 336 mm.sup.2/s at 25.degree. C. and an iodine number
of 19.4 g of iodine per 100 g of oil.
[0086] d) 13.5 g of an
.alpha.,.omega.-dihydridodimethylpolysiloxane (content of Si-bonded
hydrogen: 0.310% by weight) having a viscosity of 3.7 mm.sup.2/s at
25.degree. C. and 86.5 g of a methyl-terminated
polydimethylsiloxane with a mean chain length of about 103 siloxy
units and a viscosity of 200 mm.sup.2/s at 25.degree. C. are
equilibrated with PNCl.sub.2 catalysis (40 ppm) at 140.degree. C.
under nitrogen and with stirring for two hours. After cooling to
70.degree. C., 1.0 g of magnesium oxide are added to the reaction
mixture, which is finally brought to room temperature with
stirring. After filtration, the product is heated to constant
weight over forty minutes at 120.degree. C. under a high vacuum (1
mbar). This gives 91.7 g (91.7% of theory) of a clear, colorless
oil having a viscosity of 37 mm.sup.2/s at 25.degree. C. and a
content of Si-bonded hydrogen of 0.042% by weight (VSV). The
polymer contains on average 65 mol-% of hydridodimethylsiloxy
groups.
[0087] 20 g of VSV, 3.88 g of an ethoxylated butinediol diacrylate
having a molecular weight of about 440 g/mol (8.8 nmol of C.dbd.C),
300 ppm of hydroquinone monomethyl ether based on the mass of
diacrylate and 7.76 g of toluene are thermally conditioned to
120.degree. C. with stirring. Then 47.8 mg of a 1% strength by
weight (based on elemental platinum) solution, in toluene, of a
tris(divinyltetramethyldisiloxane)diplatinum complex are added and
the reaction mixture is stirred at 120.degree. C. for twenty
minutes. After filtration, the product is heated to constant weight
for fifteen minutes at 100.degree. C. under a high vacuum (1 mbar).
This gives 22.9 g (95.8% of theory) of a clear, yellow oil having a
viscosity of 103 mm.sup.2/s at 25.degree. C. and an iodine number
of 18.7 g of iodine per 100 g of oil.
[0088] e) 29.8 g of an
.alpha.,.omega.-dihydridodimethylpolysiloxane (content of Si-bonded
hydrogen: 0.310% by weight) having a viscosity of 3.7 mm.sup.2/s at
25.degree. C. and 70.2 g of a methyl-terminated
polydimethylsiloxane with a mean chain length of about 390 siloxy
units and a viscosity of 5000 mm.sup.2/s at 25.degree. C. are
equilibrated with PNCl.sub.2 catalysis (40 ppm) at 140.degree. C.
under nitrogen and with stirring for two hours. After cooling to
70.degree. C., 1.0 g of magnesium oxide are added to the reaction
mixture, which is finally brought to room temperature with
stirring. After filtration, the product is heated to constant
weight over forty minutes at 120.degree. C. under a high vacuum (1
mbar). This gives 93.8 g (93.8% of theory) of a clear, colorless
oil having a viscosity of 22.3 mm.sup.2/s at 25.degree. C. and a
content of Si-bonded hydrogen of 0.092% by weight (VSVI). The
polymer contains on average 95 mol-% of hydridodimethylsiloxy
groups.
[0089] 20 g of VSVI, 8.10 g of an ethoxylated butinediol diacrylate
having a molecular weight of about 440 g/mol (18.4 mmol of
C.dbd.C), 300 ppm of hydroquinone monomethyl ether based on the
mass of diacrylate and 16.2 g of toluene are thermally conditioned
to 120.degree. C. with stirring. Then 56.2 mg of a 1% strength by
weight (based on elemental platinum) solution, in toluene, of a
tris(divinyltetramethyldisiloxane)di- platinum complex are added
and the reaction mixture is stirred at 120.degree. C. for twenty
minutes. After filtration, the product is heated to constant weight
for fifteen minutes at 100.degree. C. under a high vacuum (1 mbar).
This gives 26.2 g (93.4% of theory) of a clear, yellow oil having a
viscosity of 67 mm.sup.2/s at 25.degree. C. and an iodine number of
33.3 g of iodine per 100 g of oil.
[0090] f) Polymer AC I:
[0091] 80 g of an .alpha.,.omega.-dihydridodimethylpolysiloxane
(content of Si-bonded hydrogen: 0.346% by weight) having a
viscosity of 3.7 mm.sup.2/s at 25.degree. C. and 488.5 g of a
methyl-terminated polydimethylsiloxane with a mean chain length of
about 275 siloxy units and a viscosity of 2000 mm.sup.2/s at
25.degree. C. are equilibrated with PNCl.sub.2 catalysis (40 ppm)
at 140.degree. C. under nitrogen and with stirring for two hours.
After cooling to 70.degree. C., 5.7 g of magnesium oxide are added
to the reaction mixture, which is finally brought to room
temperature with stirring. After filtration, the product is heated
to constant weight over forty minutes at 120.degree. C. under a
high vacuum (1 mbar). This gives 525 g (92.3% of theory) of a
clear, colorless oil having a viscosity of 71 mm.sup.2/s at
25.degree. C. and a content of Si-bonded hydrogen of 0.041% by
weight (VSIV). The polymer contains on average 84 mol-% of
hydridodimethylsiloxy groups.
[0092] 20 g of VSIV, 3.77 g of an ethoxylated butinediol diacrylate
having a molecular weight of about 440 g/mol (9.2 mmol of C.dbd.C),
300 ppm of hydroquinone monomethyl ether based on the mass of
diacrylate and 15 g of toluene are thermally conditioned to
120.degree. C. with stirring. Then 54.6 mg of a 1% strength by
weight (based on elemental platinum) solution, in toluene, of a
tris(divinyltetramethyldisiloxane)diplatinum complex are added and
the reaction mixture is stirred at 120.degree. C. for twenty
minutes. After filtration, the product is heated to constant weight
for fifteen minutes at 100.degree. C. under a high vacuum (1 mbar).
This gives 20.5 g (86% of theory) of a clear, yellow oil having a
viscosity of 346 mm.sup.2/s at 25.degree. C. and an iodine number
of 17.8 g of iodine per 100 g of oil (AC I).
[0093] g) Comparison polymer AC II:
[0094] 20 g of an .alpha.,.omega.-dihydridodimethylpolysiloxane
having a content of Si-bonded hydrogen of 0.049% by weight
(0.97.multidot.10.sup.-- 2 mol of SiH) and a viscosity of 67
mm.sup.2/s at 25.degree. C., 4.47 g of an ethoxylated butinediol
diacrylate having a molecular weight of about 440 g/mol
(1.02.multidot.10.sup.-2 mol of C.dbd.C), 300 ppm of hydroquinone
monomethyl ether, based on the mass of diacrylate, 17.9 g of
toluene and 62.7 .mu.l (20 ppm of platinum, based on pure metal) of
a solution of hexachloroplatinic acid in isopropanol, having a
platinum content of 1% by weight, are thermally conditioned at
110.degree. C. with stirring in a reaction vessel. After a reaction
period of 30 minutes at 110.degree. C. the reaction mixture is
filtered and the filtrate is concentrated to constant weight under
a high vacuum at 100.degree. C. This gives 20.3 g (83% of theory)
of a clear, yellow oil having a viscosity of 320 mm.sup.2/s at
25.degree. C. and an iodine number of 20.6 g of iodine per 100 g of
oil (AC II).
EXAMPLE 1 AND COMPARISON EXPERIMENT 1
[0095] Polymer AC I and AC II, whose preparation has been described
above under f) and g), respectively, are each admixed with 3% by
weight of 2-hydroxy-2-methyl-1-phenolpropan-1-one (Darocur 1173,
from Ciba-Geigy). The finished formulations are applied in a
coating thickness of about 3 .mu.m using a glass rod to the
substrates specified in Table 1 and are cured at 30.degree. C. for
three seconds under a nitrogen atmosphere containing 20 ppm of
residual oxygen and under a 300 series H lamp from Fusion. To
determine the rub-off (abrasion) the coated substrates are
stretched between thumb and forefinger. Then the finger of the
other hand is used to rub rapidly backward and forward a number of
times under vigorous pressure on the stretched substrate. If the
adhesion of the silicone film to the substrate surface is poor,
some of the silicone applied is abraded. The rub-off is given a
rating of 1-6 in accordance with its extent, a completely undamaged
surface receiving the rating 1.
1TABLE 1 Comparison of rub-off values Substrates Treated Bosso
silicone ChamTenero HDPE N925 Polyprop- paper T 4377 841 Q24000*
(from ylene* (from (from Cham (from 4 P Bosso) (from UCB) Finnpap)
Tenero AG) Folie) AC II 4 5 2 5 3 AC I 2 3 1 3 1 *The
abovementioned films were not corona-pretreated before coating.
[0096] As Table 1 clearly shows, the novel, cured silicone films
with polymer AC I exhibit better adhesion and abrasion resistance
on all substrates.
EXAMPLE 2
[0097] 25 g of
oligo[2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propano- ne]
(obtainable commercially under the trade name "ESACURE KIP 150"
from Lamberti) are thermally conditioned at 60.degree. C. for one
hour. Then 125 g of a short-chain .alpha.,.omega.-diacrylated
dimethylpolysiloxane of the general formula
A(CH.sub.3).sub.2SiO[(CH.sub.3).sub.2SiO].sub.13Si(CH.sub.3).sub.2A,
[0098] where A is a radical of the formula 4
[0099] are metered in and the mixture is stirred vigorously for 30
minutes. A brown solution having a viscosity of 350 mm.sup.2/s at
25.degree. C. is obtained (PI I).
[0100] Firstly 3% by weight of
2-hydroxy-2-methyl-1-phenylpropan-1-one (obtainable commercially
under the trade name "Darocur 1173" from Ciba-Geigy) and 12% by
weight of the above-described short-chain
.alpha.,.beta.-diacrylated dimethylpolysiloxane and secondly 15% by
weight of PI I whose preparation has been described above are added
to polymer AC I, whose preparation has been described above under
f). The finished formulations are applied to the respective
substrates and cured as described in Example 1. The rub-off
(abrasion) and thus the assessment of the anchorage to the
substrate are as described in Example 1. The results are summarized
in Table 2.
2TABLE 2 Rub-off values with different photoinitiators Substrates
Treated Bosso silicone ChamTenero HDPE N925 Polyprop- paper T 4377
841 Q24000* (from ylene* (from (from Cham (from 4 P Bosso) (from
UCB) Finnpap) Tenero AG) Folie) Daro- 3 4 2 4 2 cure 1173 PI I 1 1
1 1 1
[0101] As Table 2 clearly shows, the novel cured silicone films
with polymer AC I in conjunction with the novel oligomeric
photoinitiator formulation PI I exhibit optimum adhesion and
abrasion resistance on all substrates.
* * * * *