Patent Application
20050004275
The present invention relates to a stabilizer composition and also to its use for stabilizing non-living organic material with respect to exposure to light, oxygen, and heat.
The mechanical, chemical, and/or esthetic properties of non-living organic material, in particular plastics and paints, are known to be impaired by exposure to light, oxygen, and heat. This impairment is usually apparent in the form of yellowing, discoloration, cracking, or embrittlement of the material. Stabilizers or stabilizer compositions are intended to give satisfactory protection from impairment of organic material by light, oxygen, and heat.
EP 0 791 032 discloses the use of certain 3-arylacrylates as stabilizers, including light stabilizers, for non-living organic material. The 3-arylacrylates may be used in combination with sterically hindered amines or with sterically hindered phenols.
EP 0 263 524 relates to a stabilizer mixture made from chromane derivatives and from organic phosphites or phosphonites for stabilizing plastics, and this stabilizer mixture may, where appropriate, also comprise other stabilizers.
DE-A-4405670 relates to a stabilizer mixture made from chromane derivatives and from organic phosphites or phosphonites, and from amines, for stabilizing organic material.
DE 199 48 117 discloses a stabilizer composition which comprises a 3-arylacrylate, a sterically hindered amine, a chromane derivative, and an organic phosphite and/or phosphonite.
An unsatisfactory factor with these stabilizer compositions is often the low duration of protective action.
It is an object of the present invention to provide a stabilizer composition which provides long lasting protective action at a high level, in particular with regard to gloss retention, with respect to exposure to light, oxygen, and heat. The stabilizer composition is intended to be particularly effective in stabilizing polyurethanes.
We have found that this object is achieved by way of a stabilizer composition which comprises
A) at least one 3-arylacrylate of the formula I
where
B) at least one amine of the formula II
where
C) at least one phenol of the formula III
where
D) at least one chromane derivative of the formula IV
where R7 is a group of the formula
and
E) at least one organic phosphite and/or phosphonite.
At room temperature, the stabilizer composition of the invention is generally a viscous liquid, and its incorporation into the material to be stabilized, and its homogeneous distribution therein, are therefore easy.
It has also been found that the protective action of the stabilizer composition of the invention with respect to exposure to light, oxygen, and heat is higher than would be expected from the contributions of the components of the stabilizer composition. The well-developed protective action provided by the stabilizer composition of the invention is therefore based on a synergistic effect of the components.
As component A), the stabilizer composition of the invention encompasses a 3-arylacrylate of the formula I
Examples of Ar in Formula I are
Particular preference is given to C1-C4-alkoxyphenyl radicals, in particular those where the position of the alkoxy radical on the phenyl core is para.
R1 is a straight-chain or branched C1-C20-alkyl group, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, neo-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, isotridecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, n-eicosyl; or a straight-chain or branched C2-C20-alkylene group, e.g. vinyl, allyl, methallyl, oleyl, linolyl or linolenyl; or a C3-C8-cycloalkyl group, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl. Among these, preference is given to-straight-chain or branched C5-C16-alkyl groups, in particular straight-chain or branched C8-C12-alkyl groups. Of particular interest are straight-chain or branched C8-alkyl groups. Among the cycloalkyl groups, preference is given to cyclopentyl and cyclohexyl.
The groups mentioned may have substitution by up to three radicals selected from the group consisting of halogen, cyano, nitro, amino, C1-C4-alkylamino, C1-C4-dialkylamino, hydroxy, C1-C4-alkyl, and C1-C4-alkoxy.
Examples of Halogen are Fluorine, Chlorine, and Bromine.
The radicals R2 and R3, independently of one another, are in particular hydrogen, methyl, or ethyl. It is very particularly preferable that in the formula I R2 is hydrogen or methyl and R3 id hydrogen.
2-Ethylhexyl p-methoxycinnamate is particularly preferred as 3-arylacrylate of the formula I.
As component B), the stabilizer composition of the invention comprises at least one sterically hindered monomeric amine of the formula II
where
Each of R4 and R5, independently of the other, is hydrogen, a straight-chain or branched C1-C4-alkyl group, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, or a straight-chain or branched C1-C12-alkoxy group, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, n-hexyloxy, iso-hexyloxy, n-octyloxy, 2-ethylhexyloxy, iso-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, or n-dodecyloxy. Particularly suitable groups among these are hydrogen, methyl, and the isomeric octyloxy groups.
The compounds which may be used as component B) may be liquid to crystalline. Particularly suitable compounds are bis-(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate, commercially available with the name Lowilite® 76 from the company Great Lakes, bis-(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, commercially available with the name Lowilite® 77 from the company Great Lakes, bis-(2,2,6,6-tetramethylpiperidin-4-yl) succinate, commercially available with the name Tinuvin® 780 FF 35 from the company Ciba-Geigy, bis-(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, commercially available with the name Tinuvin® 123 from the company Ciba-Geigy. It is preferable to use sterically hindered monomeric amines which at room temperature or below 100° C. are liquid, an example being bis-(1,2,2,6,6-penta-methylpiperidin-4-yl) sebacate.
As component C), the stabilizer composition of the invention comprises at least one phenol of the formula III
where
Particularly suitable compounds for this purpose are (3,5-di-tert-butyl-4-hydroxyphenyl)propionates of C1-C20-alkanols, for example isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, commercially available with the name Irganox® 1135 from the company Ciba-Geigy, or n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, commercially available with the name Irganox® 1076 from the company Ciba-Geigy.
As component D), the stabilizer composition of the invention comprises at least one chromane derivative of the formula IV
where R7 is a group of the formula
Particularly suitable compounds for this purpose are 2,5,7,8-tetramethyl-2-(2′-stearoyloxyethyl)chromane (R7=—CH2CH2—O—CO—C17H35), and in particular α-tocopherols, preferably D,L-α-tocopherol (R7=—(CH2)3—CH(CH3)—(CH2)3—CH(CH3)—(CH2)3—C(CH3)2).
As component E), the stabilizer composition of the invention comprises at least one organic phosphite and/or phosphonite.
Particularly suitable compounds for this purpose are organic phosphites of the formula V
The phosphites and phosphonites which may be used according to the invention may be either liquid or crystalline. Examples which may be mentioned of phosphites of the formula V are:
The phosphonite of the formula VI is available commercially with the name Irgafos® P-EPQ from the company Ciba-Geigy.
The stabilizer composition of the invention also optionally comprises at least one other light stabilizer which absorbs radiated light in the UV-A (320-400 nm) and/or UV-B (280-320 nm) region. Of course, the additional light stabilizers have to be compatible with the stabilizer composition, and preferably colorless in the visible region. Examples which may be mentioned of UV absorbers of this type are: 2-hydroxybenzophenones, 2-hydroxyphenylbenzotriazoles, oxanilides, 2-hydroxyphenyl-triazines, 4,4′-diarylbutadienes.
Examples of suitable 2-hydroxybenzophenones, of which a wide variety is commercially available, are: 2-hydroxy-4-methoxy-benzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-dodecoxy-benzophenone, 2,2′-dihydroxy-4-methoxybenzophenone (trade name Cyasorb® UV 24, American Cyanamid), 2,2′-dihydroxy-4,4′-di-methoxybenzophenone, 2,2′,4,4′-tetrahydroxybenzophenone. The 2-hydroxybenzophenones feature good UV resistance and high absorptive power.
Examples of suitable 2-hydroxyphenylbenzotriazoles are 2-(2′-hydroxy-5′-methylphenyl)benzotriazole (trade name Tinuvin® P, Ciba-Geigy), 2-(2′-hydroxy-5′-tert-octylphenyl)-benzotriazole (trade name Cyasorb® UV 5411), 2-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl)benzotriazole (trade name Tinuvin® 326, Ciba-Geigy), 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-5-chlorobenzotriazole (trade name Tinuvin® 327, Ciba-Geigy). 2-Hydroxyphenylbenzotriazoles absorb at the limit of the visible region and do not exhibit any yellow coloration.
An example of a suitable 2-hydroxyphenyltriazine is 2,4-bis-(2′, 2″,4′,4″-tetramethylphenyl)-6-(2′″-hydroxy-4′″-octyloxy-phenyl)-1,3,5-triazine (trade name Cyasorb® 1164, American Cyanamid).
Examples of Preferred Oxanilides are:
4,4′-Diarylbutadienes of the Formula VII
are known from EPA 916 335. The substituents R11 and/or R12 are preferably C1-C8-alkyl and C5-C8-cycloalkyl.
The stabilizer composition of the invention generally comprises
If concommitant use is made of another light stabilizer, its amount used is preferably from 0.1 to 15 parts by weight, preferably from 1 to 12 parts by weight, based on the total weight of the stabilizer composition.
The concentration of the stabilizer composition of the invention added to the organic material to be stabilized, prior to, during, or after its preparation, is generally from 0.01 to 5% by weight, preferably from 0.01 to 2% by weight, in particular from 0.05 to 1% by weight, based on the organic material.
Examples of non-living organic material are cosmetic preparations, such as ointments and lotions, pharmaceutical formulations, such as pills and suppositories, photographic recording materials, in particular photographic emulsions, precursors of plastics and paints, and in particular the actual paints and plastics themselves.
Examples which may be mentioned of plastics which can be stabilized by the stabilizer mixture of the invention are:
The paints which may be stabilized using the stabilizer composition of the invention include paints such as alkyd resin paints, emulsion paints, epoxy resin paints, polyurethane paints, acrylic resin paints, cellulose nitrate paints, and varnishes, such as wood-protection varnishes.
The stabilizer composition of the invention is particularly suitable for stabilizing polyurethanes, in particular thermoplastic polyurethanes. These are mainly linear polyurethanes which are obtained from diisocyanates, such as 4,4′-diisocyanatodiphenylmethane, and from long-chain diols, such as polytetrahydrofuran or polyester polyols. The starting material used is generally appropriate prepolymers, and short-chain diols or diamines are used as chain extenders. The resultant products have a segmented structure, examples of molecular weights of the soft segments being from 1 000 to 3 000, these being crosslinked physically by the hard segments.
The stabilizer composition of the invention may also be prepared in the form of a masterbatch, for example one which comprises a concentration of from 2.5 to 25% by weight of the composition, the masterbatch being added to the materials to be stabilized.
The materials stabilized using the stabilizer composition of the invention exhibit particular quality features with regard to color change and gloss retention when compared with materials stabilized with the comparative composition, i.e. their impairment by external effects is delayed. There should be a maximum of retention of gloss and color during entire service life, and loss of these always means loss of quality. The materials stabilized according to the invention therefore feature a prolonged service time.
The examples below give further illustration of the invention.
1. Determination of Gardner Gloss Level
Gloss is measured using a Gardner Micro-Gloss 600 reflectometer to DIN 67530.
2. Determination of Color Difference
Prior to and after weathering, the CIELAB color differences ΔE were calculated for each specimen from the tristimulus values with the aid of the color difference formula. The CIE tristimulus values X, Y, and Z were determined for the specimens using the DataColor color-measurement device from Datacolor.
A stabilizer composition 1 was prepared from:
A stabilizer composition 2 was prepared from:
The comparison used was a commercially available stabilizer composition whose makeup was as follows:
The stabilizer was added to a TPU reaction, and the samples here were produced by casting.
1% by weight of the stabilizer composition of example 1 was incorporated into one specimen, and 1% by weight of the stabilizer composition of example 2 was incorporated into another specimen. The comparison used was a specimen into which 1% by weight of the stabilizer composition of the comparative example has been incorporated. Since rapid yellowing occurred under the test conditions in the case of the unstabilized specimen, it was not possible to use the unstabilized specimen to carry out a control test.
Test specimens were weathered using a Weather-Ometer® accelerated weathering device from the company Atlas Materials Testing Technology B.V., the Netherlands. Gardner gloss (table 1) and color change (table 2) were determined as a function of weathering time. The results are given in tables 1 and 2 below.
n.d. not determined
In relation to gloss level, the specimens stabilized with the stabilizer compositions of the invention exhibited particularly good gloss retention, and stabilizer composition 1 featured particularly long lasting action here.
As can be seen from table 2, the specimens stabilized using the stabilizer compositions of the invention exhibited markedly less color change than the specimen stabilized using the comparative composition after weathering for 1000 hours.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101 61 863.8 | Dec 2001 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP02/14236 | 12/13/2002 | WO |
