DE4327297A1 - New hindered amine light stabilisers and polymeric compsns. contg. them - Google Patents

Abstract

A compsn. comprises a thermoplastic material and a cpd. of formula (I), where R = H, O, OH, 1-24C alkyl, -O- 1-24C alkyl, -O-CO- 1-24C alkyl, -O-CO- phenyl or -CORs; R5 = -C(R3)=CH2, 1-6C alkyl, phenyl, -CO- 1-24C alkyl, -CO- phenyl, -NR7R8, -CH2C6Hs, -CO-O- 1-12C alkyl or -COOH; R3 = H or 1-4C alkyl; R7 = H, 1-12C alkyl, 5-6C cycloalkyl, phenyl, phenyl- 1-4C alkyl or 1-12C alkyl phenyl; R8 = 1-12C alkyl or H; each R1 = independently -CH3 or -CH2 (1-4C alkyl) or both R1 form a gp. -(CH2)s; R2 = as defined for R1; A = O, N(1-4C alkyl) or NH; R9 = H or methyl; and R10 = an aromatic single ring or an aromatic fused 2 or 3 ring gp. or a heteroaromatic single ring or a heteroaromatic fused 2 or 3 ring gp.

Description

It has been found that piperidine compounds of the formula I

wherein R _{1 is} hydrogen, hydroxyl, low molecular weight alkyl, low molecular weight alkoxy or acyl,
R _{2 has} a mono- or dinuclear radical of aromatic (also heteroaromatic) character which may have substituents and
R _{3 is} oxygen, -NH- or -N (C _1-4 alkyl) - and
all R _{8 are} independently hydrogen or methyl,
can bind chemically to plastics very easily and thus receives light-stabilized plastics, the stabilizer of which is practically inseparable from this plastic.

The invention thus relates to the use of the piperidine compounds of formula I above for preparation with HALS compounds (these are as Stabilizing piperidine compounds or residues) chemically bound whose plastics.  

The term plastics here primarily includes unsaturated ones Monomers produced polymers, but also others, with radicals rea ying plastics, especially polyolefins, but also corresponding Paint materials, e.g. B. to understand polyurethane paints or acrylic paints.

The compounds of the formula I are particularly suitable for stabilizing Polyolefins, i.e. H. especially for polypropylene and all variants of poly ethylene (high-pressure, medium and low-pressure polyethylene), polyisobutylene, Poly-4-methylpentene and its copolymers.

As additional stabilizers u. a. Antioxi dantien, e.g. B. sterically hindered phenols, secondary aromatic amines or Thioether (described e.g. in "Plastics Additives", Gächter and Müller, 1985, pp. 8-12), UV absorber (especially 2- (2'-hydroxyphenyl) benzotriazole compounds, 2-hydroxybenzophenone compounds, 1,3-bis (2'-hydroxybenzoyl) - benzenesalicylates, cinnamic acid derivatives and oxalic acid anilides), antistatic agents, flame retardants, plasticizers, nucleating agents, metal desacti vators, biocides, fillers and pigments are used.

Low molecular weight alkyl preferably contains residues with 1-4, in particular To understand 1 or 2 carbon atoms, preferably come as "acyl" Residues of formic, acetic or propionic acid into consideration.

All R ₁ are preferably hydrogen, hydroxyl, methyl or C _1-2 alkoxy, especially hydrogen or methyl, especially methyl.

Among mono- or dinuclear residues of aromatic character come e.g. B. Five or five containing benzene, naphthalene and nitrogen and / or sulfur Six-membered rings, optionally fused to a benzene ring, in Consider the z. B. carry sterically hindered hydroxyl as a substituent (3,5-di-butyl-4-hydroxyphenyl), or a thienyl radical. Are preferred Benzene rings. As substituents on these rings z. B. hydroxyl, low molecular weight alkyl or alkoxy, preferably methyl, tert-butyl, Methoxy, ethoxy, hydroxyl and one or two groups of the formula

to be named.

All R _{8 are} preferably hydrogen.

The invention also relates to the still new compounds of the formula I, they correspond to formulas Ia and Ib

wherein R _{1 is} hydrogen, low molecular weight alkyl, low molecular weight alkoxy or acyl, R _{3 is} oxygen, -NH- or -N (C _1-4 alkyl) -, R _{4 is} 3,5-di- (tert-butyl) -4 -hydroxyphenyl radical, a mononuclear or dinuclear, heterocyclic, optionally substituent-bearing radical of aromatic character or a radical of the formula a

R _{5 is} an optionally substituted phenyl radical, R _{6 is} hydroxyl or low molecular weight alkoxy and
all R _{8 is} hydrogen or methyl
mean.

The compounds of formula I can be the plastics to be stabilized already during the production (conversion of the monomers, production of the lacquers) be added. In the case of polyolefins, the compounds of Formula I also mixed with the powdered plastic, fused and to thin moldings (e.g. fibers, threads, films, tapes or thin Plates) are processed in which the chemical bond by exposure is produced with high-energy visible or near UV light. The Be lightening is generally dependent on the thickness of the plastic, between about 100 and 400 hours, e.g. B. in the light of a xenon lamp or in Sunlight performed.

It is also possible to use voluminous molded articles made of the invention with the connector formulations of staggered plastics and manufactured by exposure be stabilized. In this case, the inside of the molded body migrate existing HALS connections slowly against the surfaces and there, by exposure to chemicals chemically attached to the plastic bound. If necessary, destroyed HALS stabilizers on the Surface replaced again and again and the stabilization on essential extended for a long time.

In general, 0.05 to 2.5%, in particular 0.1 to 0.5%, of one or more compounds of formula I, based on the weight of the stabilizing plastic. This is compared to the usual type Use a small amount of HALS stabilizers.

After exposure, the stabilizers (compounds of the formula I) by physical means, in particular elution, with which solvent anyway, can no longer be removed from the plastics.

A preferred application of the stabilizers of the formula I is in polyols find out what all known plastics of this type are to be understood. It deserves to be mentioned that catalyst (residues / degradation products) polyolefins containing are equally stabilized according to the invention can. An example of such polyolefins is with a catalyst  III. Generation (Ziegler complex catalysts based on magnesium halide ger) made polypropylene, not from the catalyst and residues have been removed. Generally, polyolefins can be used with all catalysts Generations were produced (see DE-OS 42 22 648) according to the invention be implemented.

In general, base-stabilized polyolefin is stabilized according to the invention siert. The basic stabilization generally takes place, as is known, at approximately 0.1% of a phenolic antioxidant and about 0.1% calcium stearate on the weight of the polyolefin.

The formation of the chemical bond between the compounds of formula 1 and the plastic molecules take place by breaking the double bond in the compound of formula I and addition to appropriately reactive Carbon atoms in the polymer.

The compounds of the formula I (likewise those of the formula Ia and Ib) are by condensation of a mole of a compound of formula II

R₂-CH = C = (COOH) ₂ (II)

or a functional acid derivative, e.g. B. a low molecular weight ester or an acid halide, with 2 moles of a compound of formula III

manufactured according to generally known methods. The connections of the Formulas II and III are known. A preferred group of compounds Formula I corresponds to Formula Ic

wherein the symbols R ₁ , R ₃ and R _{8 have} the meanings given above and R _{7 is} a meta or, preferably, a para-phenyl radical, or a 2,5-thienylene radical.

These compounds of the formula Ic are prepared by condensates tion of a mole of a compound of formula IV

R ₇ [CH = C (COOH) ₂ ] ₂ (IV)

or a functional acid derivative of such a compound, with four moles of a compound of formula III. The compounds of the formula Ia in which R _{4 is} a radical of the formula a are also prepared in an analogous manner by condensation of one mole of a compound of the formula V.

R₉ - [- CH = C (COOH) ₂] ₃

wherein R₉ is a radical of the formula

is prepared with 6 moles of a compound of formula III.

In the following examples, parts mean parts by weight and Percentages by weight. The volume parts correspond to the volume of the same Parts by weight of water. The temperatures are given in degrees Celsius.  

example 1

84 parts of para-methoxy-benzalmalonic acid dimethyl ester with 154 parts 1,2,2,6,6-pentamethyl-4-hydroxypiperidine distributed in 80 parts of xylene Heated to 80 °, mixed with 0.5 parts by volume of tetraisopropyl orthotitanate and, while distilling off the resulting methanol, 22 hours at about 140 ° touched. The reaction solution is then cooled to 80 °, three times with 150 Washed parts of water, separated the organic phase, the solvent distilled off and the residue recrystallized from ethanol. The received Product of the formula

melts at 121-123 °.

Example 2

20.9 parts of the tetraethyl ester of the compound of formula IV, wherein R₇ is para-phenylene, 28 parts of 1,2,2,6,6-pentamethyl-4-hydroxypiperidine and 110 parts by volume of xylene and 0.8 parts by volume of tetraisopropyl orthotitanate , as described in Example 1, and the reaction product, the compound of the formula Ic in which R _{1 is} methyl, R _{3 is} oxygen and R _{7 is} para-phenylene, is isolated. The melting point of the purified compound is 234-238 °.

Example 3

Analogously to the information in Example 1, benzalmalonic acid and 1,2,2,6,6-pentamethyl-4-hydroxypiperidine transesterified. The product obtained melts at 95-96 °.  

Examples 4 to 6

25.9 parts of 4-methoxy-benzalmalonic acid dichloride made from 4-methoxy benzalmalonic acid and thionyl chloride, is dissolved in anhydrous xylene with 98 parts of 2,2,6,6-tetramethyl-4-aminopiperidine (Ex. 4), 11.0 parts of 1.2 2,6,6-pentamethyl-4-aminopiperidine (Ex. 5), or 12.5 parts of 1-formyl 2,2,6,6-tetramethyl-4-aminopiperidine (Ex. 6) condensed.

Examples 7 to 12

Analogous to the information in the first example, 18.8 parts of 3,5-di-tert.butyl-4- hydroxy-benzalmalonic acid diethyl ether, (Ex. 7), 14.4 parts of 3,4-dimethoxy benzalmalonic acid diethyl ether (Ex. 8), 13.8 parts of 4-methyl mercaptobenzal diethyl malonate (Ex. 9), 16, 2 parts of diethyl 4-phenylbenzalmalonate ester (Ex. 10), or 12.7 parts of 1- (thienyl-2 ′) - 2-bis- (ethoxycarbonyl) ethylene (Ex. 11) with 18.8 parts of 1,2,2,6,6-pentamethyl-4-hydroxypiperidine implemented.

Examples 12 to 14

Analogous to the information in Example 2, 21.2 parts of the tetraethyl ester of the compound of the formula IV in which R _{7 is} para-phenylene with 25 parts of 2,2,6,6-tetramethyl-4-hydroxypiperidine (Ex. 12), 28 parts 1,2,2,6,6-penta methyl-4-hydroxypiperidine (Ex. 13), or 31 parts of 1-acetyl-2,2,6,6-tetra methyl-4-hydroxypiperidine (Ex. 14) transesterified .

Examples 15 to 16

Analogous to the information in the first example, 84 parts of para-methoxybenzal dimethyl malonate with 160 parts of 1-methoxy-2,2,6,6-tetramethyl-4- hydroxypiperidine (Example 15), or 180 parts of 1-n-octyloxy-2,2,6,6-tetra methyl-4-hydroxypiperidine transesterified and isoslated.  

Example 17

Commercial polypropylene in powder form, base stabilized with 0.1% Calcium stearate and 0.1% of a phenolic stabilizer, (Irganox 1010 from Ciba-Geigy) was mixed with 0.1% of the stabilizer according to Example 1, melted and processed into a film, thickness 0.1 mm. A part of each The film was exposed to the light of a xenon lamp for 50 hours and 200 hours puts. These two samples and an unexposed film sample were exposed to Di chloromethane eluted and the content of stabilizer determined in the eluate. At the entire amount of stabilizer could be eluted from the unexposed sample are only 10% for the 50 hours exposed sample and for the 200th Hours of exposed sample could no longer be eluted from the stabilizer.

The results with those prepared according to Examples 2 to 16 Stabilizers are practically identical.

After the fixation thus obtained, these HALS stabilizers protect the Plastic at least as good as non-chemically bound HALS Stabilizers.

Claims (4)

1. Use of piperidine compounds of the formula I. wherein R _{1 is} hydrogen, hydroxyl, low molecular weight alkyl, low molecular weight alkoxy or acyl,
R _{2 is} a mono- or dinuclear radical of aromatic character which may have substituents
R _{3 is} oxygen, -NH- or N (C _1-4 -alkyl) - and all R ₈ independently of one another are hydrogen or methyl,
for the production of chemically bound plastics with HALS compounds. 2. The compounds of formula Ia wherein R _{1 is} hydrogen, low molecular weight alkyl, low molecular weight alkoxy or acyl,
R _{3 is} oxygen, -NH- or -N (C _1-4 alkyl) -,
R _{4 is} a 3,5-di- (tert.butyl) -4-hydroxyphenyl radical, a mono- or dinuclear, optionally substituted heterocyclic radical of aromatic character or a radical of the formula a and all R _{8 are} independently hydrogen or methyl. 3. The compounds of formula Ib wherein R _{3 is} oxygen, -NH- or -N (C _1-4 alkyl),
R _{5 is} an optionally substituted phenyl radical R _{6 is} hydroxyl or low molecular weight alkoxy and
all R _{8 are} hydrogen or methyl. 4. Plastics containing 0.05 to 2.5 percent by weight of a remainder Compound of formula I according to claim 1 in chemically bound form contain.