4-hydroxyquinoline-3-carboxylic acid derivatives as light...

Details 4-hydroxyquinoline-3-carboxylic acid derivatives as light... 4-hydroxyquinoline-3-carboxylic acid derivatives as light...

1998-09-03

2001-02-27

Huang, Evelyn Mei (Department: 1612)

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

Synthetic resins

Processes of preparing a desired or intentional composition...

C524S089000, C524S108000, C546S156000, C252S384000, C252S405000, C252S609000

Reexamination Certificate

active

06194493

ABSTRACT:

BACKGROUND OF THE INVENTION
It is known that organic materials are damaged by light, radiation, heat or oxygen. There are already numerous documents which describe compounds for stabilizing organic material against said effects. Such compounds are usually free-radical scavengers, hydroperoxide decomposers, quenchers (extinguishers for excited states) or UV absorbers (cf. R. Gächter, H. Müller, Plastics Additives Handbook, 3rd Ed., Hanser Verlag, Munich 1990, p. 133 ff). In connection with UV absorbers, the compounds involved are generally based on 2-hydroxybenzophenone, 2-hydroxyphenylbenzotriazole, cinnamic esters and oxanilides (cf. R. Gächter, H. Müller, Plastics Additives Handbook, 3rd Ed., Hanser Verlag, Munich 1990, p. 181 ff). The class of the o-hydroxy-substituted triphenylpyrimidines can also be regarded as a separate type of UV stabilizer (DE-A4 416 809).
Said classes of compound often have specific disadvantages which occur alongside the desired stabilizing effect. In respect in particular of color characteristics, interaction with pigments, compatibility of different stabilizers with one another and with the material to be stabilized, resistance to chemicals and water (sensitivity to hydrolysis), storage stability, migration behavior and improvement in stabilization to the harmful effects of heat and light, especially in long-term use, there is a great need for new classes of stabilizer.
Derivatives of 4-hydroxyquinoline-3-carboxylic acid of the formula (I) have been known for some time in connection with pharmaceutical applications (cf. e.g. E. Schroetter et al., Pharmazie (1977), 32(4), 223-5).
The applications relate to the action of compounds of the formula (I) against bacteria, parasites, tumors, suppurating ulcers, gastrointestinal dysfunctions and as enzyme inhibitors. Nothing is known of any stabilizing action of compounds of the formula (I) on organic material, especially their potential as UV absorbers.
Processes for preparing compounds of the formula (I) are known, for example, from Organic Syntheses Coll. Vol. III, p. 274; Houben-Weyl, Heterarene II, Part 1, Volume E7a, p. 343 ff.
SUMMARY OF THE INVENTION
It has now been found surprisingly that compounds of the formula (I) provide outstanding stabilization of organic material against the harmful effects of light, heat and oxygen. The substances (I) possess absorption bands in the UV region with extinction coefficients of up to more than 20,000.
This represents a new class of stabilizer, which effectively protects organic and inorganic material against the harmful effects of heat and light. The compounds of this new class of stabilizer can be applied to the external layer of the material to be stabilized, or mixed in with the material.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention therefore provides for the use of compounds of the formula (I) as a stabilizer for organic material against the harmful effect of light, oxygen and heat,
where
R
1
to R
5
independently of one another are halogen, H, NO
2
, CF
3
, CN; C
1
-C
20
−
, preferably C
1
-C
10
−
, especially C
1
-C
4
-alkyl, —S-alkyl or —O-alkyl; C
6
-C
14
−
, preferably C
6-C
10
-aryl, —S-aryl or O-aryl; C
5
-C
13
−
, preferably C
5-C
10
-heteroaryl; C
7-C
26
−
, preferably C
7-C
13
-alkylaryl, —S-alkylaryl or —O-alkylaryl.
Two of the radicals R
1
to R
4
can together with the parent structure form a 5-12-membered, preferably a 5-6-membered aliphatic ring which is unsubstituted or substituted by halogen, NO
2
, CN, CF
3
, C
1
-C
20
−
, preferably C
1
-C
10
−
, especially C
1
-C
4
-alkyl, —O-alkyl or —S-alkyl, C
6
-C
14
−
, preferably C
6
-C
10
-aryl, —O-aryl or —S-aryl, C
5
-C
13
−
, preferably C
5
-C
10
-heteroaryl, C
7
-C
26
−
, preferably C
7
-C
13
-alkylaryl, —O-alkylaryl or —S-alkylaryl and which can include one or more heteroatoms; this aliphatic ring can, in particular, be interrupted by —S—, —O—, —N(H)—.
Of the radicals R
1
to R
4
, two adjacent radicals in each case can together with the parent structure form a further 5-6-membered, preferably 6-membered aromatic ring which is unsubstituted or substituted by halogen, NO
2
, CF
3
, CN, C
1
-C
20
−
, preferably C
1
-C
10
−
, especially C
1
-C
4
-alkyl, —O-alkyl or —S-alkyl, C
6
-C
14
−
, preferably C
6
-C
10
-aryl, —O-aryl or —S-aryl, C
5
-C
13
−
, preferably C
5
-C
10
-heteroaryl, C
7-C
26
−
, preferably C
7
-C
13
-alkylaryl, —O—-alkylaryl or —S-alkylaryl and which can include one or more heteroatoms or can be fused to a further aromatic nucleus.
R
6
is —O— or —N(R
8
)—,
where R
8
is hydrogen or C
1
-C
12
−
, preferably C
1
-C
4
−
alkyl, but especially hydrogen.
R
7
is H, C
1
-C
30
-alkyl, preferably C
1
-C
16
-alkyl, especially C
1
-C
5
-alkyl, C
3
-C
12
-cycloalkyl, preferably C
5
-C
6
-cycloalkyl; C
6
-C
14
-aryl which is unsubstituted or substituted by halogen, NO
2
, CN, CF
3
, CF
3
, O—C
1
-C
20
−
, preferably O—C
1
-C
10
−
, especially O—C
1
-C
4
-alkyl, O—C
6
—C
14
−
, preferably O—C
6
-C
10
-aryl, or O—C
7
-C
26
−
, preferably O—C
7
-C
13
-arylalkyl; C
7
-C
30
-arylalkyl which is unsubstituted or substituted by halogen, NO
2
, CF
3
, O—C
1
-C
20
20
, preferably O—C
1
-C
10
−
, especially O—C
1
-C
4
-alkyl, O—C
6
-C
14
−
, preferably O—C
6
—C
10
-aryl or O—C
7-C
26
−
, preferably O—C
7
-C
13
-arylalkyl; or is a heteroaromatic radical having 5-15 carbon atoms.
When used in organic material they can be added in solid form, in the form of a melt, in a form dissolved in solvents or else as a masterbatch to the material that is to be stabilized, before, during or after polymerization. When added in solid form, the compounds of the formula (I) are particularly suitable in finely divided form. A masterbatch is particularly appropriate when it comprises the novel stabilizer in a concentration of from 1 to 80%, but preferably of 5-30% by weight, the remainder of the masterbatch being a polymer compatible with the polymer to be stabilized. Incorporation in dissolved form is particularly appropriate, in which case the solutions can comprise the novel stabilizer, for example, in a concentration of 5-80% by weight. Both the solution and the masterbatch may additionally contain further stabilizers or effect substances, examples being further UV absorbers, light stabilizers based on sterically hindered amines, quenchers, antioxidants, pigments, acid scavengers or fillers. The novel stabilizers are preferably employed such that their concentration in the polymer to be stabilized is from 0.001 to 5% by weight, preferably from 0.02 to 2% by weight, based on the organic material, and they are present either alone or in combination with further additives.
By organic material is meant, for example, precursors of plastics, paints, varnishes and oils, but especially plastics, paints, varnishes and oils themselves.
The stabilizers of the formula (I) are particularly suitable for stabilizing films, fibers, tapes, multifilaments, wovens, extruded, blow molded, injection molded and thermoformed articles, powder coating materials, printing inks, toner inks, photographic material, pigments, wood stains, leathers, architectural paints, protective coatings for steel structures, lubricating oils, machine oils, bitumen and asphalt. They are also suitable for cosmetic or pharmaceutical applications, in which the UV-absorbing nature of the compounds of the formula (I) is of advantage. Compounds of the formula (I) are also suitable for use in UV filters, especially when these compounds are dissolved or embedded in polymeric material.
The stabilizers of the formula (I) according to the invention can also be employed advantageously in combinations with further stabilizers. The result of these novel combinations are mixtures having an improved profile of properties with respect to the individual components, such as synergies in the photoprotective effect, for example.
The present invention additionally provides an organic material stabilized against the action of li

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