Compositions – Liquid crystal compositions
Reexamination Certificate
2001-08-10
2004-05-11
Huff, Mark F. (Department: 1756)
Compositions
Liquid crystal compositions
Reexamination Certificate
active
06733689
ABSTRACT:
The present invention relates to a liquid-crystalline composition which comprises, as components,
A) a liquid-crystalline mixture comprising as least one compound selected from the group consisting of the compounds of the formula Ia
Z
1
—Y
1
—A
1
—Y
3
—M
1
—Y
4
—A
2
—Y
2
—Z
2
Ia
and of the formula Ib
Z
3
—Y
5
—A
3
—Y
7
—M
2
—P Ib,
where the variables, independently of one another, have the following meanings:
P is hydrogen, C
1
-C
15
-alkyl or a —Y
8
—A
4
—Y
6
—Z
4
group,
Z
1
to Z
4
are polymerizable groups,
Y
1
to Y
8
are linking groups,
A
1
to A
4
are spacers,
M
1
and M
2
are mesogenic groups,
B) if desired, further additives selected from the group consisting of
b1) photoinitiators,
b2) reactive thinners and
b3) diluents,
C) if desired, further additives taken from the group consisting of
c1) antifoams and deaerators,
c2) lubricants and flow auxiliaries
c3) thermally curing or radiation-curing auxiliaries,
c4) substrate wetting auxiliaries,
c5) wetting and dispersion auxiliaries,
c6) hydrophobicizing agents,
c7) adhesion promoters and
c8) auxiliaries for improving the scratch resistance,
D) if desired, further additives selected from the group consisting of
d1) dyes and
d2) pigments
and
E) if desired, further additives selected from the group consisting of light, heat and/or oxidation stabilizers.
A detailed definition of the variables Z
1
to Z
4
, Y
1
to Y
8
, A
1
to A
4
, P, M
1
and M
2
is given in the following description.
The present invention furthermore relates to the use of a liquid-crystalline composition of this type as a printing ink, for printing or coating substrates, in electro-optical components, for counterfeiting-proof marking of articles and for the production of films or coatings which selectively reflect light in the wavelength range from 250 to 1300 nm.
The present invention furthermore relates to a polymer or polymerized film obtained by polymerizing a liquid-crystalline composition according to the current invention and to the use of a polymerized film of this type as an optical filter, polarizer, decoration, counterfeiting-proof marking or reflection medium for the selective reflection of radiation in the wavelength range of 250 to 1300 nm.
The present invention furthermore relates to a process for printing or coating the substrate using a liquid-crystalline composition according to the invention.
The present invention furthermore relates to substrates to which a liquid-crystalline composition according to the invention or a polymer or polymerized film according to the invention has been applied or which has been printed or coated by the process according to the invention.
The specification WO 96/02597 describes a process for coating or printing substrates with a coating or printing composition which comprises said liquid-crystalline, polymerizable monomers. The coating or printing composition comprises either a chiral liquid-crystalline monomer or an achiral liquid-crystalline monomer and a non-liquid-crystalline compound, and polymeric binders and/or monomeric compounds which can be converted into the polymeric binder by polymerization.
According to the examples given in this specification, these printing or coating compositions can be applied to various substrates by diverse application methods, for example by spraying or offset printing, where, after curing, for example by irradiation with UV light, they form strongly adhering layers which are resistant to external influences.
However, layers obtained in this way usually do not exhibit the desired degree of brilliance and brightness. Furthermore, the m printing and coating compositions described are not ideally suitable for printing, in particular in screen printing, clonographic printing and letterpress printing, inter alia owing to their viscosity, which is without exception high.
It is an object of the present invention to provide a liquid-crystalline composition which can be used, inter alia, as a printing ink in common printing methods and enables the production of prints having high color fastness, brilliance and whiteness and the production of homogeneous and smooth liquid-crystalline layers and films.
We have found that this object is achieved by the liquid-crystalline composition described at the outset, which, in addition to the optional components B) to E), comprises, as component
A) a liquid-crystalline mixture comprising at least one compound selected from the group consisting of the compounds of the formula Ia
Z
1
—Y
1
—A
1
—Y
3
—M
1
—Y
4
—A
2
—Y
2
—Z
2
Ia
and of the formula Ib
Z
3
—Y
5
—A
3
—Y
7
—M
2
—P Ib,
where the variables, independently of one another, have the following meanings:
Z
1
to Z
4
are polymerizable groups,
Y
1
to Y
8
are each a single chemical bond, oxygen, sulfur, —O—CO—, —CO—O—, —O—CO—O—, —CO—NR—, —NR—CO—, —CO—NR—, —NR—CO—O— or —NR—CO—NR—,
R is hydrogen or C
1
-C
4
-alkyl,
A
1
to A
4
are spacers having 1 to 30 carbon atoms, in which the carbon chain may be interrupted by ether oxygen, thioether sulfur or by non-adjacent imino or C
1
-C
4
-alkylimino groups.
P is hydrogen, C
1
-C
15
-alkyl, which may be monosubstituted or polysubstituted by methyl, fluorine, chlorine or bromine and in which non-adjacent CH
2
-groups may be replaced by oxygen, sulfur, —CO—, —O—CO—, —CO—O— or —O—CO—O—, or a —Y
8
—A
4
—Y
6
—Z
4
group, where the variables are as defined above,
M
1
is a mesogenic group of the formula Ic
—T
1
—Y
9
—T
1′
— Ic,
and
M
2
is a mesogenic group of the formula Id
(—T
2
—Y
10
)
r
—T
2
— Id,
where the variables in the formulae Ic and Id, independently of one another, are as defined below:
T
1
, T
1′
and T
2
are divalent saturated or unsaturated carbocyclic or heterocyclic radicals,
Y
9
and Y
10
are bridging units as defined for Y
1
to Y
8
or —CH
2
—O—, —O—CH
2
—, —CH═N—, —N═CH— or —N═N—,
r is a value of 0, 1, 2 or 3,
where the radicals T
2
and Y
10
, in the case where r is not 0, may be identical or different.
Component A) of the novel liquid-crystalline composition covers both liquid-crystalline mixtures which comprise pure liquid-crystalline compounds of the formulae Ia and/or Ib and mixtures which additionally include non-liquid-crystalline mixture constituents, but overall have liquid-crystalline behavior. These non-liquid-crystalline mixture constituents are usually byproducts formed during synthesis of liquid-crystalline compounds or during synthesis of mixtures of the liquid-crystalline compounds.
Besides the liquid-crystalline compounds of the formulae Ia and/or Ib (and the byproducts), component A) preferably also comprises at least one chiral compound, which, however, need not necessarily itself have liquid-crystalline behavior. The presence of such chiral compounds results—at least within certain temperature ranges—in the formation of chiral-nematic (cholesteric) phases, which usually have interesting optical properties.
However, it should be pointed out that, for the purposes of the present invention, the liquid-crystalline composition or the liquid-crystalline mixtures (component A)) need not necessarily include such chiral compounds.
Suitable polymerizable groups Z
1
to Z
4
are—in combination with the bridging units Y
1
to Y
8
— for example:
where Y is as defined for the bridging units Y
1
to Y
8
, i.e. a single chemical bond, oxygen, sulfur, —O—CO—, —CO—O—, —O—CO—O—, —CO—NR—, —NR—CO—, —O—CO—NR—, —NR—CO—O— or —NR—CO—NR—, and R is hydrogen or C
1
-C
4
-alkyl, i.e. methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl or tert-butyl, and Y′ is a single chemical bond (hereinafter, the polymerizable groups Z
1
to Z
4
in combination with the bridging units Y
1
to Y
8
are referred to as polymerizable units or as Z—Y and/or Z—Y′).
Of these polymerizable units, the cyanates can spontaneously trimerize to cyanurates. The maleimido group is particularly suitable for free-radical copolymerization with liquid-crystalline compounds of the formula Ia and/or Ib containing styryl groups as polyme
Ishida Hiroki
Meyer Frank
Neumann Horst
Schuhmacher Peter
BASF Drucksysteme GmbH
Huff Mark F.
Sadula Jennifer R.
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