Cross-linkable compounds, optionally containing MQ silicon...

Details Cross-linkable compounds, optionally containing MQ silicon... Cross-linkable compounds, optionally containing MQ silicon...

1999-09-30

2001-08-14

Dawson, Robert (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From silicon reactant having at least one...

C528S015000, C528S031000, C528S033000, C427S387000, C525S474000, C525S477000, C525S478000, C556S434000, C556S435000, C556S453000

Reexamination Certificate

active

06274692

ABSTRACT:

The invention relates to crosslinkable compositions comprising
(A
1
) organosilicon compounds containing aliphatically unsaturated hydrocarbon radicals
and, if desired,
(A
2
) MQ silicone resin,
(B) organosilicon compounds containing Si-bonded hydrogen atoms,
(C) catalysts which promote the addition of Si-bonded hydrogen onto aliphatic multiple bond, and, if desired,
(D) agents which retard the addition of Si-bonded hydrogen onto aliphatic multiple bond at room temperature
and to their use for producing coatings which repel tacky substances.
EP-B 403890 (Bayer A G; published on 16.03.1994) and the corresponding U.S. Pat. No. 5,077,369, and also EP-A 640662 (Bayer A G; laid open on 01.03.1995) describe addition-crosslinking organopolysiloxane mixtures for producing adhesion-reducing coatings. The organopolysiloxanes present in the mixtures are branched, with the branching sites representing trifunctional monoorganosiloxy groups, so-called T units, and/or tetrafunctional siloxy groups, so-called Q units. In addition they possess triorganosiloxy groups, so-called M units, as end groups, which contain at least one unsaturated hydrocarbon radical.
U.S. Pat. No. 5,082,915 (Shin-Etsu Chemical Company Ltd.; published on 21.01.1992) describes paper-coating compositions which comprise a branched organopolysiloxane having at least two Si-bonded alkenyl groups and at least one SiC-bonded siloxane side chain of the formula —(CH
2
)
m
(R
1
2
SiO)
n
—SiR
1
3
per molecule, where R
1
is a monovalent hydrocarbon radical, preferably a methyl radical, m is an integer from 2 to 8 and n is an integer from 5 to 100.
EP-A 761 790 (Dow Corning Corporation; laid open on Mar. 12, 1997) discloses crosslinkable silicone coating compositions which comprise organopolysiloxanes having Si-bonded vinyl groups or higher alkenyl groups and SiC-bonded groups of the formula —(CH
2
)
n
Si(OR)
3
(where R is a monovalent hydrocarbon radical and n is an integer from 2 to 20).
The use of MQ silicone resins as agents for adjusting the release force in coating compositions is known from U.S. Pat. No. 4,123,604 (Dow Corning Corporation; published on Oct. 31, 1978), EP-B 535 687 (Wacker-Chemie GmbH; published on Jun. 15, 1994) and EP-B 607 869 (Wacker-Chemie GmbH; published on Apr. 5, 1995).
The object was to provide novel compositions based on organosilicon compounds which crosslink in the presence of catalysts by the addition of Si-bonded hydrogen onto aliphatic multiple bond. A further object was to provide novel compositions for the production of coatings which repel tacky substances. Yet another object was to provide abhesive coating compositions which give abrasion-resistant coatings, i.e. which adhere to the substrate such that they cannot be separated by mechanical influences, for example by rubbing, from the substrate, so that they do not become partly detached when carriers located on them and provided with adhesive, such as labels, are peeled off, which would otherwise reduce the bonding strength of the labels. A further object was to provide abhesive coating compositions which give tack-free well-cured coatings. These objects are achieved by the invention.
The invention provides crosslinkable compositions comprising
(A
1
) linear organopolysiloxanes containing aliphatically unsaturated hydrocarbon radicals, of the general formula
R
1
a
R
3-a
SiO(R
2
SiO)
c
[R
2
Si—Y—SiR
2
O(R
2
SiO)
c
]
d
SiR
3-b
R
1
b
  (I)
where R can be identical or different and is a monovalent, unsubstituted or halogenated hydrocarbon radical which has from 1 to 18 carbon atoms per radical and is free from terminal aliphatic carbon—carbon multiple bonds,
R
1
is a monovalent aliphatically unsaturated hydrocarbon radical having from 2 to 14 carbon atoms 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,
and the sum a+b per molecule is 1 or 2,
c is an integer from 1 to 1000 and
d is 0 or an integer from 1 to 10,
and, if desired,
(A
2
) MQ silicone resins which are soluble in (A
1
), with the proviso that without the use of MQ silicone resins (A
2
) the sum a+b in formula (I) is on average from 1.3 to 1.9, and that with the use of MQ silicone resins (A
2
) the sum a+b in formula (I) is on average from 1.0 to 1.9,
(B) organosilicon compounds containing Si-bonded hydrogen atoms,
(C) catalysts which promote the addition of Si-bonded hydrogen onto aliphatic multiple bond,
and, if desired,
(D) agents which retard the addition of Si-bonded hydrogen onto aliphatic multiple bond at room temperature.
The invention also provides a process for producing coatings which repel tacky substances, by applying crosslinkable compositions comprising
(A
1
) linear organopolysiloxanes containing aliphatically unsaturated hydrocarbon radicals, of the general formula
R
1
a
R
3-a
SiO(R
2
SiO)
c
[R
2
Si—Y—SiR
2
O(R
2
SiO)
c
]
d
SiR
3-b
R
1
b
  (I)
where R, R
1
, Y, a, b, c and d have the meaning indicated above for them,
and, if desired,
(A
2
) MQ silicone resins which are soluble in (A
1
),
with the proviso that
without the use of MQ silicone resins (A
2
) the sum a+b in formula (I) is on average from 1.3 to 1.9, and that with the use of MQ silicone resins (A
2
) the sum a+b in formula (I) is on average from 1.0 to 1.9,
(B) organosilicon compounds containing Si-bonded hydrogen atoms,
(C) catalysts which promote the addition of Si-bonded hydrogen onto aliphatic multiple bond,
and, if desired,
(D) agents which retard the addition of Si-bonded hydrogen onto aliphatic multiple bond at room temperature
to the surfaces which are to be made repellent to tacky substances and subsequently curing the crosslinkable composition.
The linear organopolysiloxanes (A
1
) according to the invention, containing aliphatically unsaturated hydrocarbon radicals, preferably possess a viscosity of from 5 to 20,000 mm
2
/s at 25° C., preferably from 20 to 1000 mm
2
/s at 25° C. and, with particular preference, from 20 to 500 mm
2
/s at 25° C.
The organopolysiloxanes according to the invention preferably have iodine numbers of between 1 and 80, preferably between 4 and 15, the iodine number indicating the amount of iodine, in grams, consumed in the course of addition onto the double bond, per 100 rams of organopolysiloxane of the invention that is employed.
Examples of radicals R are 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, hexadecyl radicals, such as the n-hexadecyl radical, and octadecyl radicals, such the n-octadecyl radical, cycloalkyl radicals, such as the cyclopentyl, cyclohexyl and 4-ethylcyclohexyl radical, cycloheptyl radicals, norbornyl radicals and methylcyclohexyl radicals, aryl radicals, such as the phenyl, biphenylyl, naphthyl and anthryl and phenanthryl radicals; alkaryl radicals, such as o-, m-, p-tolyl radicals, xylyl radicals and ethylphenyl radicals aralkyl radicals, such as the benzyl radical, and also the &agr;- and the &bgr;-phenylethyl radical.
The radical R is preferably the methyl radical.
Examples of halogenated radicals R are haloalkyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2′,2′,2′-hexafluoroisopropyl radical and the heptafluoroisopropyl radical, and haloaryl radicals, such as the o-, m- and p-chlorophenyl radicals.
Y is preferably a divalent hydrocarbon radical which can contain one or more separate oxygen atoms.
Examples of radicals Y are those of the formula —CH
2
CH
2
—, —CH(CH
3
)—, —(CH
2
)
4
—, —(CH
2
)
5
—, —(CH
2
)
6
—, —(CH
2
)
8
—, —(C

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