EP0874821A1

EP0874821A1 - Tetramethylpiperidine-containing copolymers

Info

Publication number: EP0874821A1
Application number: EP96939088A
Authority: EP
Inventors: Alfred Krause; Alexander Aumüller; Hubert Trauth; Albin Berger; Andreas Deckers
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1995-11-29
Filing date: 1996-11-18
Publication date: 1998-11-04
Also published as: WO1997019922A1; AU7627096A; JP2000501132A; DE19544404A1; US5973040A

Abstract

The invention concerns tetramethylpiperidine-containing copolymers comprising between 1 and 100 mol % identical or different monomer units of general formula (I), in which R?1 = COOR7, COR8, CONR8R9, CN; R2¿ = H, C¿1?-C12 alkyl, COOR?7, COR8, CONR8R9, CN; R3¿ = H, methyl, ethyl, propyl; R6 = H, C¿1?-C8 alkyl; R?7¿ = H, C¿1?-C8 alkyl, C5-C8 cycloalkyl, C3-C5 alkenyl, substituted or nonsubstituted phenyl; R?8 and R9¿ = H, C¿1?-C12 alkyl, C5-C8 cycloalkyl, substituted or nonsubstituted phenyl; X = oxygen, sulphur, NR?6¿, and further monomers. The invention further concerns processes for preparing the copolymers, the use thereof as stabilizers or agents for protecting against light, and organic material containing the copolymers.

Description

Copolymers containing tetramethylpiperidine

description

The present invention relates to copolymers containing tetramethylpiperidine

I) 1 to 100 mol% of the same or different monomer units of the general formula I

and

I) 0 to 99 mol% of the same or different monomer units of the general formula II

where the substituents and bridge members have the following meaning:

X oxygen, sulfur or NR ⁶ ,

R ¹ COOR ⁷ , COR ⁸ , CONR ⁸ R ⁹ or CN,

R ² hydrogen, C ₁ -C ₁₂ alkyl, COOR ⁷ , COR ⁸ , CONR ⁸ R ⁹ or CN,

R ^{3 is} hydrogen, methyl, ethyl or propyl, R ^{4 is} hydrogen, straight-chain or branched Ci-C ₂ n-alkyl, where every third C atom of the chain can be replaced by oxygen or NR ⁶ , C ₃ -C ₈ cycloalkyl, phenyl, or a radical of the formulas

A CH ₂ CH ₂ <fy OH ^or A CH ₂ CH ₂ NR ⁿ Rl2

R ^{5 is} hydrogen, methyl, ethyl or propyl

R ^{6 is} hydrogen, or Ci-Cβ-alkyl,

R ^{7 is} hydrogen, Cι ~ to C _θ- alkyl, C ₅ - to Cβ-cycloalkyl, C ₃ - to Cs-alkenyl or phenyl, which by one to three Cι ~ to C ₄ alkyl radicals, Cχ ~ to C ₄ alkoxy radicals , Ci to C ₄ alkoxycarbonyl groups, halogen atoms, hydroxyl groups, phenoxy groups, phenyl groups, tolyl groups or

Xylyl radicals can be substituted,

R ⁸ u. R ^{9 is} hydrogen, C 1 to C ₂ alkyl, C ₅ to Cs cycloalkyl or phenyl, which is substituted by one to three C 1 to C ₄ alkyl radicals, C 1 to C ₄ alkoxy radicals, C 1 to C ₄ alkoxycarbonyl groups ,

Halogen atoms, hydroxyl groups, phenoxy groups, phenyl radicals, tolyl radicals or xylyl radicals can be substituted,

R ^{10 is} hydrogen or methyl,

R ¹¹ u. R ¹² C ₁ -C ₄ alkyl

A is a bridge member of the formula

_R ιo

(CH ₂ CH X) rm, n 0 or 1 and

r means 0 to 100

The invention further relates to processes for the preparation of the compounds, the use of the copolymers as light stabilizers and stabilizers and organic material which is stabilized against the action of light, oxygen and heat and which contains the copolymers. Organic material, especially plastics and lacquers, is very quickly destroyed by light, oxygen and heat, which can be seen, for example, in yellowing, discoloration, embrittlement or cracking. This destruction is to be prevented with light stabilizers and stabilizers and the organic material is to be largely protected from these damaging influences.

Among the light stabilizers and stabilizers, compounds with hindered amine units such as the tetramethylpiperidine structure have proven to be particularly suitable. Tetramethylpiperidine compounds with several piperidine residues have proven to be particularly advantageous, e.g. dimeric or polymeric structures, since these can diffuse out of the stabilized organic material only with difficulty and therefore have particularly long-lasting protective effects.

In US 4413096 α-olefin copolymers are described which contain side chains with tetraalkylpiperidine residues. These tetraalkylpiperidine residues can on the nitrogen atom with hydrogen, oxyl, -CC ₈ alkyl, C ₃ -C ₆ alkenyl, C ₃ -C ₆ alkynyl, C ₇ -C _β aralkyl,

-CH ₂ CN, C ₂ -C ₂ -alkoxyalkyl, an aliphatic acyl group with 1-4 carbon atoms or one of the groups -CH ₂ COOR or -COOR substituted, where R in turn can be various organic radicals.

Often unsatisfactory with such agents of the prior art is the low compatibility with plastics, the duration of the protective action, the intrinsic color of the compounds, the thermal decomposability when incorporated at elevated temperature, and in particular the sensitivity to acidic, sulfur and halogen-containing solids, liquids and Gases.

It was therefore an object of the present invention to provide stabilizers and light stabilizers for organic material which have more effective protection against light, oxygen and heat, in particular in combination with better protection against acidic liquids and gases.

Accordingly, the copolymers containing tetramethylpiperidine described at the outset were found.

Oxygen is preferred as the bridge member X.

The group COOR ^{7 is} preferred as the radical R ¹ . The radical R ² is preferably hydrogen or COOR ⁷ .

The radicals R ³ and R ^{5 are} preferably hydrogen or methyl.

R ⁴ is preferably hydrogen, methyl, phenyl or a radical of the formulas

The latter two radicals R ⁴ are particularly preferred in the event that m and n = 1 and X is oxygen or NR ⁶ .

R ⁶ is preferably hydrogen, methyl or ethyl.

R ⁷ is preferably C ₁ -C ₄ alkyl, particularly preferably ethyl.

R ² , R ⁴ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , RH and R ¹² are, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and tert-butyl.

The radicals R ² , R ⁴ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are furthermore n-pentyl, isopentyl, sec. -Pentyl, tert. -Pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl and 2-ethylhexyl.

R ² , R ⁴ , R ² and R ⁹ are furthermore n-nonyl, iso-nonyl, n-decyl, n-undecyl and n-dodecyl.

Cycloalkyl radicals such as, in particular, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl and ethylcyclohexyl are also suitable as radicals R ⁴ , R ⁷ , R ⁸ and R ⁹ .

The radical R ⁴ can also mean cyclopropyl and cyclobutyl.

C ₃ -C ₅ alkenyl radicals are also suitable as the radical R ⁷ , especially allyl, methallyl, crotyl, pentenyl, 1,3- and 2,4-pentadienyl.

The copolymers according to the invention contain the tetramethylpiperidine residue as an effective stabilizer unit. This is particularly easy to access and has particularly advantageous properties. However, other tetraalkylpiperidine residues show very similar properties, in which one or more of the methyl residues are replaced by other alkyl residues such as ethyl, propyl, butyl or each because two adjacent methyl radicals are linked to form a cyclic radical.

Among the copolymers according to the invention, preference is given to those in which the sum of the monomer units I and II derived from acrylate or methacrylate, ie monomer units in which m and n = 1 and R ⁵ and R ^{3 are} hydrogen or methyl, between 1 and 80 mol -%, based on the total amount of monomer units in the copolymer. Copolymers in which this proportion is between 1 and 50 mol% are particularly preferred.

The copolymers preferably have an average molecular weight (weight average) between 1000 and 50,000 daltons, particularly preferably between 1000 and 25,000 daltons.

The copolymers according to the invention can advantageously be prepared by polymer-analogous reactions. For this purpose, a copolymer is exposed, for example

I) 1 to 100 mol% of the same or different monomer units of the general formula Ia

wherein R ^{13 is} hydrogen, methyl, ethyl, propyl, butyl or dimethyl aminoethyl, and

II) 0 to 99 mol% of the same or different monomer units of the general formula II

with a compound of general formula III

H ₃ C CH ₃ in the melt or in an inert high-boiling solvent with removal of the volatile reaction products in a polymer-like manner.

The starting copolymer preferably contains 1-80 mol% of component Ia, particularly preferably 1-50 mol% and 99-20 mol%, particularly preferably 99-50 mol% of component II, the latter then consists of monomers in which m or n = 0. Component Ia is derived from an acrylic ester in which the alcohol radical R ^{13 can} preferably be methyl or ethyl, but also hydrogen or dimethylaminoethyl.

The polymer-analogous reaction is carried out in a manner known per se, preferably by azeotropic esterification or amidation, the water of reaction formed or the alcohol R ¹³ OH released being removed from the reaction mixture by distillation. For azeotropic esterification or amidation, an inert, high-boiling entrainer is added to the starting material mixture, which is distilled off together with the water or alcohol. The entrainer can then be separated from the water, for example, and returned to the reaction mixture. In this case, a relatively small addition of entrainer of 50-200% by weight based on the expected amount of water is sufficient. Without recycling, an up to 30-fold excess of entraining agent is generally added, and the entraining agent can also be added continuously.

As entrainer e.g. Toluene, xylene, cyclohexane, methyl cyclohexane or even commercially available mixtures of aromatic hydrocarbons into consideration, toluene is preferably used.

The distillation temperature depends both on the boiling point of the entrainer or azeotrope and on the reaction pressure. The distillation can be carried out at normal pressure, but distillation is preferably carried out under reduced pressure of, for example, 50-400 mbar. The temperature is generally between 100 and 250 ° C, particularly preferably 150 ° -200 ° C.

The polymer-analogous reaction can also be carried out in the melt, for example in a kneader or extruder. The choice of temperature depends primarily on the melting point of the starting polymer. The reaction is generally carried out at 80-300 ° C., preferably at 120-250 ° C., distillation under reduced pressure being advantageous, for example at 50-400 mbar. Like the reaction in solution, the reaction in the melt can also be carried out continuously or batchwise. The reaction is preferably carried out in the presence of a catalyst. Suitable catalysts are, for example, protonic acids such as p-toluenesulfonic acid, sulfuric acid, phosphoric acid, Lewis acids such as tetraalkyl titanates or organotin compounds or basic compounds such as alkaline earth metal hydroxides and carbonates as well as lithium and sodium amide.

The preparation of the compounds III is described, for example, in DE-A 4140304 or is possible according to the methods described there.

The synthesis of copolymers from 1-olefins and acrylic acid derivatives is described, for example, in Houben Weyl, Methods of Organic Chemistry. Volume XIV / 1 described.

The copolymers according to the invention are outstandingly suitable for stabilizing organic material against the action of light, oxygen and heat, in particular when acidic liquids or gases are exposed at the same time.

Organic material means, for example, cosmetic preparations such as ointments and lotions, pharmaceutical formulations such as tablets and suppositories, photographic recording materials, in particular photographic emulsions or precursors for plastics and lacquers, but especially plastics and lacquers.

The present invention also relates to organic material stabilized against the action of light, oxygen and heat, in particular plastics and paints, containing 0.01 to 5% by weight, preferably 0.02 to 1% by weight. based on the total weight of the organic material, one or more copolymers according to the invention.

All known devices and methods for mixing stabilizing agents or other additives into polymers can be used to mix the copolymers according to the invention, especially with plastics.

The organic material stabilized by the copolymers according to the invention may optionally contain further additives, for example antioxidants, light stabilizers, metal deactivators, antistatic agents, flame retardants, pigments and fillers. Antioxidants and light stabilizers which can be added in addition to the compounds according to the invention are, for example, compounds based on sterically hindered phenols or costabilizers containing sulfur or phosphorus.

Examples of such phenolic antioxidants are 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1, 1, 3-tris- (2-methy- 1-4-hydroxy-5-tert-butyl-phenyl) -butane, 1,3, 5-trimethyl-2, 4,6-tris- (3, 5-di-tert-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris - [ß- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl ethyl] isocyanurate, 1,3, 5-tris- (2,6-dimethyl-3-hydroxy-4 -tert.-butylbenzyl) isocyanurate and pentaerythritol tetrakis [ß- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate] mentioned.

Examples of phosphorus-containing antioxidants are tris (nonylphenyl) phosphite, distearylpentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (2-tert-butyl-4-methylphenyl) -phosphite. Bis- (2,4-di-tert-butylphenyl) -pen- taerythritol diphosphite and tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene diphosphite into consideration.

Examples of sulfur-containing antioxidants are dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentarythritol tetrakis (β-lauryl thiopropionate) and pentaerythritol tetrakis (β-hexylthiopropionate).

Other antioxidants and light stabilizers which can be used together with the copolymers according to the invention are e.g. 2- (2'-hydroxyphenyl) benzotriazoles, 2-hydroxybenzophenones, aryl esters of hydroxybenzoic acids, α-cyanocinnamic acid derivatives, benzimidazolecarboxylic acid anilides, nickel compounds or oxalic acid dianilides.

Examples of plastics which can be stabilized by the copolymers according to the invention are:

Polymers of mono- and diolefins, such as, for example, low or high density polyethylene, polypropylene, linear polybutene-1, polyisoprene, polybutadiene and copolymers of mono- or diolefins or mixtures of the polymers mentioned; Copolymers of mono- or diolefins with other vinyl monomers, such as, for example, ethylene-alkyl acrylate copolymers, ethylene-alkyl methacrylate copolymers, ethylene-vinyl acetate copolymers or ethylene-acrylic acid copolymers;

Polystyrene and copolymers of styrene or α-methylstyrene with dienes and / or acrylic derivatives, such as Styrene-butadiene, styrene-acrylonitrile (SAN), styrene-ethyl methacrylate, styrene-butadiene-ethyl acrylate, styrene-acrylonitrile-methacrylate, acrylonitrile-butadiene-styrene (ABS) or methyl methacrylate-butadiene-styrene (MBS);

Halogen-containing polymers, e.g. Polyvinyl chloride, polyvinyl fluoride, polyvinylidene fluoride and their copolymers;

Polymers derived from α, β-unsaturated acids and their derivatives, such as polyacrylates, polymethacrylates, polyacrylamides and polyacrylonitriles;

Polymers derived from unsaturated alcohols and amines or from their acyl derivatives or acetals, e.g. Polyvinyl alcohol and polyvinyl acetate;

Polyurethanes, polyamides, polyureas, polyesters, polycarbonates, polysulfones, polyether sulfones and polyether ketones.

Coatings can also be stabilized with the copolymers according to the invention, e.g. Industrial paints. Among these, stove enamels, in particular vehicle paints, preferably two-coat paints, are particularly noteworthy. Another area of use is e.g. Paints for exterior painting of buildings, other structures or technical equipment.

The copolymers according to the invention can be added to the lacquer in solid or dissolved form. Their good solubility in coating systems is of particular advantage.

The compounds I according to the invention are notable for good compatibility with the customary types of plastics and for good solubility and excellent compatibility in the customary coating systems. As a rule, they have no or only a very slight intrinsic color, are stable at the usual plastics and lacquer processing temperatures and are not volatile and, above all, bring about a long protection period for the materials treated with them. Example e

Polymer-analogous reaction of N, N-dimethylaminoethyl acrylate-ethylene copolymers with ß- (2,2, 6, 6-tetramethyl-4-hydroxy-1-piperidinyl) acrylic acid ethyl ester (IV)

20 g of N, N-dimethylaminoethyl acrylate-ethylene copolymer with the acrylic ester content given in Table 1 (in mol%, based on the total amount of monomers in the copolymer) were mixed with different amounts of IV (see Table 1) in the presence of 0 , 5 g of p-toluenesulfonic acid as a catalyst for 4 hours at 210-220 ° C. The N, N-dimethylaminoctanol formed was distilled off and the volume of the distillate was determined in order to calculate the acrylate conversion (see Table 1). (The used

Copolymers had different molecular weights. As a measure of their size, the viscosity at 120 ° C was determined, which is also shown in Table 1.)

Table 1

Polymer-analogous implementation of acrylic acid-ethylene copolymers with IV without entrainer.

Analogously to Examples 1 to 8, 73 g of IV were reacted with 100 g of different acrylic acid / ethylene copolymers in the presence of 0.5 g of different catalysts (see Table 2), the water of reaction formed being distilled off. After cooling, the solidified reaction mixture was ground and subjected to continuous hot extraction with methanol. The residue was dried in vacuo to 50 ° C. The results (conversion of the acrylic groups, elemental analysis) are shown in Table 2.

Table 2

Polymer-analogous reaction of acrylic acid-ethylene copolymers with IV in the presence of an entrainer:

50 g of various acrylic acid-ethylene copolymers were heated to boiling with 38.3 g of IV and 0.5 g of catalyst in 150 ml of an aromatic hydrocarbon mixture with a boiling point of about 150 ° C., the distillate being separated into water and entrainer and the entrainer was returned to the reaction mixture. After cooling, the mixture was stirred into methanol. The precipitated product of value was suction filtered, washed twice with methanol and dried in vacuo at 50 ° C. The results are shown in Table 3. Table 3

Example 17

Analogously to Example 3, a corresponding copolymer was reacted with 4-hydroxy-2,2,6,6-tetramethylpiperidine (comparative sample).

0.1% by weight of the copolymers containing tetramethylpiperidine according to Example 3 and Example 17 (comparative sample) were incorporated by extrusion once in low-density polyethylene. The granules obtained were processed into 250 μm thick films. Pieces of these films were subjected to a rapid weathering test (device: Xenotest 1200). The time until embrittlement (cracking) of the test specimens was measured.

Claims

Claim

1. Copolymers containing tetramethylpiperidine

^C R3 ³

and

where the substituents and bridge members have the following meaning:

X oxygen, sulfur or NR ⁶ ,

R ¹ COOR ⁷ , COR ⁸ , CONR ⁸ R ⁹ or CN,

R ² hydrogen, C _! -Cι ₂ alkyl, COOR ⁷ , COR ⁸ , CONR ⁸ R ⁹ or CN,

R ^{3 is} hydrogen, methyl, ethyl or propyl, R ^{4 is} hydrogen, straight-chain or branched Ci-C ₂₀ alkyl, where every third C atom of the chain can be replaced by oxygen or NR ⁶ , C ₃ -C ₈ cycloalkyl, phenyl, or a radical of the formulas

A CH ₂ CH ₂ P y OH ^or A CH ₂ CH ₂ NRÜR12

R ^{5 is} hydrogen, methyl, ethyl or propyl

R ^{6 is} hydrogen, or Ci-Cβ-alkyl,

R ^{7 is} hydrogen, C 1 to C ₈ alkyl, C ₅ to C ₈ cycloalkyl, C ₃ to Cs alkenyl or phenyl, which is substituted by one to three C 1 to C ₄ alkyl radicals, C 1 to C ₄ -Alkoxy, Cι ~ to C ₄ alkoxycarbonyl groups, halogen atoms, hydroxy - groups, phenoxy groups, phenyl groups, tolyl groups or

Xylyl radicals can be substituted,

R ⁸ u. R ⁹ hydrogen f, -C ~ to -Cι ₂ alkyl, C ₅ - to C ₈ cycloalkyl or phenyl, which by one to three Ci to C ₄ alkyl radicals, Ci to C ₄ alkoxy radicals, -C ~ to C _4th Alkoxycarbonyl groups,

R ^{10 is} hydrogen or methyl,

_R ιι _u . _R i2 C ₁ -C ₄ alkyl

A is a bridge member of the formula

RIO

(CH ₂ —CH rm, n 0 or 1 and

r means 0 to 100.

2. Tetramethylpiperidine-containing copolymers according to claim 1, in which R ^{1 is} COOR ⁷ .

3. Tetramethylpiperidine-containing copolymers according to claim 1, in which R ^{2 is} hydrogen or COOR ⁷ .

4. Tetramethylpiperidine-containing copolymers according to claims 1 to 3, in which R ^{7 is} C 1 -C ₄ alkyl.

5. tetramethylpiperidine-containing copolymers according to claims 1 to 4, in which in part of the monomer units II

X = oxygen or NR ⁶ , m and n = 1 and R ⁴ a residue

^or CH ₂ CH ₂ N (CH ₃ ) ₂

means.

6. Tetramethylpiperidine-containing copolymers according to the claims

1 to 5, in which the sum of the monomer units I and II derived from acrylate or methacrylate is between 1 and 80 mol%, based on the total amount of the monomer units in the copolymer.

7. Tetramethylpiperidine-containing copolymers according to claims 1 to 6, with an average molecular weight (weight average) between 1000 and 50,000 daltons

8. A process for producing tetramethylpiperidine-containing copolymers according to claims 1 to 7 by making a copolymer

wherein R ^{13 is} hydrogen, methyl, ethyl, propyl, butyl or dimethylaminoethyl, and

II) 0 to 99 mol% of the same or different monomer units of the general formula II with a compound of general formula III

H ₃ C CH ₃

10 in the melt or in an inert high-boiling solvent with removal of the volatile reaction products in a polymer-analogous manner.

15 9. Use of the tetramethylpiperidine-containing copolymers according to claims 1 to 7 as light stabilizers and Stabilisato¬ ren for organic material.

10. Organic material stabilized against the action of light, oxygen and heat, containing 0.01 to 5% by weight, based on the total amount of the organic material, of one or more copolymers containing tetramethylpiperidine according to claims 1 to 7.

25 11. Plastics and lacquers stabilized against the action of light, oxygen and heat, containing 0.01 to 5% by weight, based on the total amount of the organic material, of one or more tetramethylpiperidine-containing copolymers according to Claims 1 to 7.

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