CH641780A5 - 1,4-Dihydropyridine-3,5-dicarboxylic acid esters - Google Patents

Abstract

The compounds of formula <IMAGE> where R is defined in Claim 1, are described. These compounds can be used for stabilising vinyl resins, including copolymers, with respect to heat and light. The thus stabilised compositions are useful for manufacturing food packagings made of plastic, floor-covering tiles or recording discs.

Description

The present invention relates to new esters of dihydropyridinedicarboxylic acids.

The compounds according to the invention correspond to the general formula:

ROCK

HORN

CH

in which R represents:

- an alkyl, alkenyl or alkinyl radical ,. linear or branched,

containing from 9 to 22 carbon atoms,

- a cyclohexyl radical, or

- a phenyl radical, optionally substituted by a halogen atom or by a methyl or methoxy radical.

In general, the dihydropyridines according to the invention can be prepared by the Hantzsch method, "Chemical Reviews", 72, 1,1972, which consists in reacting an acetoacetate of general formula:

CH3-CO-CH2-COOR (II)

in which R takes the same values as in formula I, with formalin and ammonia, optionally formed in situ.

The acetoacetates of formula II can, for their part, be prepared in two ways:

- either by action of the diketene of formula:

H „C = C — O

2 I \

CH2 ~ C = 0

on an alcohol of formula ROH, in the presence of sodium acetate,

Either by transesterification between methyl acetoacetate and an alcohol of formula ROH,

it being understood that, in the formula ROH, R represents the same values as in the formula I.

It is known that vinyl resins tend to degrade on heat and that it is essential to introduce stabilizing agents into these masses of synthetic material, in order to delay thermal degradation, and therefore coloring.

Among the organic compounds known for their heat stabilizing effect on vinyl resins, mention may be made of the compounds of formula I, in which R represents an ethyl or butyl radical. The aforementioned French patent No. 2239496 teaches that the above two compounds thermally and chemically stabilize the vinyl resins into which they are introduced in an amount of 0.2 to 1.5% by weight.

Above all, phenyl-2 indole is known as a thermal stabilizer, which has proved to be particularly advantageous due to its stabilizing power and its low toxicity. It is also widely used on an industrial scale to stabilize vinyl polymers and copolymers, in particular those used in the composition of food packaging.

It has been discovered, surprisingly, that the compounds according to the invention, incorporated in a vinyl resin in an amount of 0.01 to 0.5% by weight, stabilize said resin in light, while giving it, despite the low concentration used, satisfactory thermal stability.

This is very important, especially for the resins used in food packaging.

It is indeed obvious that one could not market food in a packaging whose color varies over time.

In addition to their photostabilizing effect, it has also been discovered that the dihydropyridines according to the invention:

- have, at concentrations between 0.01 and

0.2 per (parts per 100 parts of resin), a heat-stabilizing action on poly (vinyl chloride); this finding is important because it makes it possible to envisage the use of poly (vinyl chloride) thus stabilized as packaging for foodstuffs; at these concentrations, in fact, the extraction of the stabilizer by food is very low, if not negligible, while at concentrations greater than 0.2 per cent, it becomes significant and does not make it possible to envisage this application for certain derivatives of formula I; it has also been discovered that the extraction or migration of the stabilizer - as well as its sublimation - varies with the number of carbon atoms in the R chains; the concentration of stabilizer used can be increased to 1 per cent when it is a question of stabilizing vinyl copolymers intended for uses such as the manufacture of floor coverings or recording discs;

- exert a lubricating power on vinyl resins;

- allow, in resins containing as primary stabilizers calcium and calcium-zinc salts, to decrease the level of zinc without decreasing the stabilization of the resin; however, it is known that too high a proportion of zinc causes the appearance of defects in the resin;

- offer the possibility of using them at a concentration between 0.1 and 0.2 per for the stabilization of vinyl resins containing a plasticizer, such as dioctyl phthalate; this type of resin generally contains, as primary stabilizers, barium-cadmium and calcium-zinc salts, and it has been found that the addition of a small amount of a dihydropyridine according to the invention makes it possible to reduce the proportion of cadmium, a very expensive and toxic product, without reducing the thermal stability of the resin; in addition, the compounds according to the invention notably improve the basic shade of this type of resin, the latter approaching colorless;

- offer the possibility of recycling on machines operating in extrusion-blowing the poly (vinyl chloride) waste stabilized by the dihydropyridines of formula I;

- improve the basic shade and increase the color stability of the resins containing a dye;

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- have a greater antioxidant effect than, for example, that of di-tert.-butyl-2,6-methyl 4-phenol, antioxidant widely used in vinyl resins;

- offer the possibility of advantageously replacing the stabilizers for vinyl resins used up to now, namely 2-phenyl indole and its derivatives, aminocrotonates of heavy alcohols or polyols and tin derivatives, with the advantages:

- good thermal stability at lower concentrations, which may be between 0.01 and 0.2 per, thereby reducing the cost of stabilizing the resin,

- good light fastness,

- an improvement in the starting color of the resin and in the development of the color over time.

As mentioned above, it has been found that the compounds according to the invention also exert thermostabilisan-tes and photostabilisantes properties on vinyl chloride copolymers (vinyl chloride / vinyl acetate, vinyl chloride / chloride vinylidene, etc.). They stabilize the formulas corresponding to both rigid and flexible copolymers.

For the various applications concerned (manufacture of recording discs, tiles for covering floors, flexible sheets for various packaging, etc.), the compounds of formula I must be incorporated into vinyl resins in amounts varying from 0.01 to 1 per and preferably between 0.01 and 0.5 per.

The dihydropyridines of formula I are compatible with the various varieties of vinyl resins currently on the market as copolymers. For example, it is possible to use the resins which are obtained by suspension polymerization and listed below:

Nature of the copolymer

Commercial designation

Provider

Vinyl chloride / vinyl acetate 15% acetate

Lucovyl MA 6035

Rhône-Poulenc

Vinyl chloride / vinyl acetate 15% acetate

Lucovyl SA 6001

Rhône-Poulenc

Vinyl chloride / vinyl acetate 12.5-13.5% acetate

Vinnol H 13/50 S

Wacker

Vinyl chloride / vinyl acetate 15% acetate

Solvic 547 SA

Solvay

Vinyl chloride / vinylidene chloride 70% vinylidene chloride

Ixan SGA / 1

Solvay

These examples are of course in no way limiting.

For the preparation of some of the resin compositions tested, poly (vinyl chlorides), such as those marketed under the names Lucovyl MB 1000 (supplier Rhône-Poulenc), have also been used,

Lacqvyl S. 071 / S (supplier Ato-Chimie),

Solvic 223 (supplier Solvay).

The experimental study carried out made it possible to show that: - by comparison with the same copolymers worked under the same conditions, but without the incorporation of this type of adjuvants, the dihydropyridines of formula I stabilize the vinyl copolymers with heat and with light indisputably;

The dihydropyridines of formula I appear to be clearly superior to the aminocrotonates of alcohols or of polyols in stabilizing the vinyl copolymers with heat and with light; these observations were mainly noted for 1,4-butanediol bisaminocrotonate, methyl aminocrotonate and C16-C18 alcohol aminocrotonate; these results have been obtained for formulas giving rigid copolymers and flexible copolymers;

- The dihydropyridines of formula I exhibit thermostabilizing and photostabilizing properties much superior to those of 2-phenyl indole often used in rigid and flexible formulas to stabilize vinyl copolymers.

As for poly (vinyl chloride), the use of 1,4-dihydro-pyridines of formula I, and especially those of high molecular weight, improves the bonding time for the copolymer formulas which they stabilize. With the vinyl chloride / vinyl acetate copolymers in particular, it has been shown that, at an equimolecular concentration, the lubricity of the didodecyl derivative of formula I (R = n — C12H25—) and of the compound of formula I derived from Acropolis 35 (R = C12H25 to C15H31 linear or branched) was significantly higher than that of the dimethyl derivative of formula I (R = - CH3). The lubricating power of the dihydropyridines of formula I is at least comparable and generally higher than that of the aminocrotonates of alcohols or of polyols. As a result, from this angle, the possibility of substituting the dihydropyridines of formula I for the aminocrotonates in certain applications for which good lubricity is appreciated, as is the case for the manufacture of recording discs.

It has been frequently observed that, in the compositions examined, the dihydropyridines of formula I could be used at much lower doses than aminocrotonates or 2-phenyl indole. This possibility brings, for these molecules, a significant economic interest.

The invention will now be described in detail, both in terms of the preparation of the compounds according to the invention and in terms of their properties.

1. Preparation of products

1.1 Preparation of acetoacetates, synthesis intermediates

They were obtained by transesterification between an ROH alcohol and methyl acetoacetate. The synthesis is carried out under nitrogen in the presence of an excess of methyl acetoacetate used as reagent and solvent (3 to 4 mol of methyl acetoacetate per mole of alcohol).

The liberated methanol is removed by continuous distillation until reaching approximately 170 ° C. in the reaction medium, then the excess of methyl acetoacetate is distilled under reduced pressure (pressure of 2 to 3 mm of mercury - temperature: 155 ± 5th VS). Almost complete elimination of methyl acetoacetate is important to prevent the presence of mixed dihydropyridines in the product.

The expected acetoacetate is used directly in the raw state for the rest of the synthesis. The yield is 95-100%.

A more specific example of preparation is described below:

Example 1:

Preparation of dodecyl acetoacetate

464 g (4 mol) of methyl acetoacetate and 186 g of do-decyl alcohol are introduced into a reactor fitted with a stirrer, a Vigreux column with column head and a descending condenser. The temperature of the reaction medium is gradually raised to 165 ° C. and the methanol formed is distilled until the reaction is complete, that is to say for about 8 h. The excess methyl acetoacetate is eliminated under a reduced pressure of 8 mm of mercury and the crude dodecyl acetoacetate is collected which will be used as it is for the preparation of the corresponding dihydropyridine derivative (Example 3).

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The general method described above was observed to prepare the acetoacetates listed in the following table and which serve as synthesis intermediates for the preparation of the corresponding dihydropyridine derivatives.

In this table and the following, PM stands for molecular weight, PF for melting point, GC for gas chromatography, yield yield, product weight, min minute, s second.

The mixtures of industrial alcohols used, designated under their trade name are as follows:

Dobanol 23 (supplier: Shell-Chimie) is a mixture of alcohols

4

primary and linear synthetic fats having 12 or 13 carbon atoms;

Dobanol 25 (supplier: Shell-Chimie) is a mixture of primary and linear synthetic fatty alcohols having from 12 to 15 atoms

5 carbon;

Acropolis 35 (supplier: PUK) is a mixture of linear and branched primary synthetic fatty alcohols having from 12 to 15 carbon atoms;

oleocetyl alcohol (supplier: Henkel) is a mixture of natural fatty alcohols comprising from 12 to 20 carbon atoms (essentially from 16 and 18 carbon atoms).

Alcohols used

Prepared aceto-acetic esters

Nomenclature

Provider

Hydroxyl number

Composition by GIC (%)

PM

Yield (%)

Dobanol 23 (linear primary synthetic fatty alcohols) CnH2n + I-OH n = 12 to 13 PM average: 194 PF: 21-22 ° C

Shell-Chemistry

272.5

C12: 34.9 C13: 46.4

298.8

100

Dobanol 25 (primary and linear synthetic fatty alcohols) C „H2n + 1-OH n = 12 to 15 PM average: 207 PF: 21-23 ° C

Shell-Chemistry

258

C12: 20.1 C13: 27.4 C14 .: 25.8 C1S: 14.4

301.4

95

Acropolis 35 (branched primary synthetic fatty alcohols) C „H2n + 1-OH n = 12 to 15 PM: 208-211 PF: 21 ° C

Ugine-Kuhlmann

271

C12: 20.9 C13: 51.9 C15: 15.3

291

100

Stearyl alcohol (octadecanol-1) CH3 (CH2) 16-CH2OH PM: 270 PF: 56--60 ° C

Laserson and Sabatier

195.5

C18: 93.6

371

98

Oleocetyl alcohol (mixture of natural fatty alcohols)

PF: 20-30 ° C

Henkel

218.3

C14: 4 C16: 25.2 Ci8: 62

340.9

98.5

Behenyl alcohol (decosanol-1) PM: 326 FP: 65-68 ° C

Merck

169.7

410.6

100

Oleyl alcohol (cisoctadecene-9 ol-1) PM: 268 PF: 13-19 ° C

Givaudan

209.3

95

1.2 Preparation of the 1,4-dihydro-pyridine derivatives of formula I 1.2.1 From formalin and ammonia introduced as such into the reaction medium.

Example 2:

General preparation

Is introduced into a reactor cooled by an ice bath

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0.2 mol of the desired acetoacetate and 0.2 g of diethylamine. The solution is cooled to OC and 7.5 g (0.1 mol) of formaldehyde in 40% aqueous solution are added dropwise, while taking care to maintain the temperature below or equal to 10 ° C. .

The reaction medium is then maintained for 6 h at 0 ° C, then for 40 h at room temperature.

The solution is decanted and the aqueous phase is extracted with ether,

then the organic phases are combined and the solution is dried over anhydrous sodium sulfate.

Filter and remove the ether by evaporation, then dilute the oily residue with a portion of methanol. While maintaining the temperature at 0 ° C., ammonia is bubbled through the solution, then the solution saturated with ammonia is kept at room temperature for 12 h. The solution is drained and the product obtained is recrystallized from methanol, then from acetone.

2,6-dimethyl-3,5-dicarboxy-3,5 dihydro-1,4 pyridine is obtained.

By proceeding in the same way, the following products were prepared:

Alkyl acetoacetate used

Dihydro-1,4 pyridines I

R

Rdt

(%)

Recrystallization solvent

PF (° C)

Dodecyl acetoacetate Cyclohexyl acetoacetate

T-butyl acetoacetate

- (CH2) i ICH3

"O

ch3

/

-c — ch3 ch3

52 16.5

55

Acetone Hexane / benzene 80/20

Benzene

96 103

166

1.2.2 From formalin and ammonia formed in situ in the reaction medium.

General operating mode:

In a reactor of 11 equipped with a reflux condenser, the following are charged:

- crude acetoacetate 1 mol

- methanol 320 cm3

- purified water 27 g 35

- ammonium acetate 14.4 g

- hexamethylenetetramine 35 g

The mass is brought to reflux with stirring and a stream of nitrogen. In doing so, the mass becomes progressively clear.

Maintained for 2.5 to 3 hours at reflux and observed the formation of a precipitate or, according to tests, the demixing of an oil.

After returning to room temperature, the mixture is kept at -5 / - 10 ° C for 2 h, then wrung.

Ammonium ions and hexamethylenetet-amine are then removed by abundant rinsing with purified water and washed with heptane to remove the corresponding pyridine formed by oxidation, to finally dry at constant weight in a vacuum oven (50 ° C. under 10 mm of mercury).

More specific modes of execution of this general process are set out below:

Example 3:

Preparation of 2,6-dimethyl-3,5-dicarbododecyloxy-1,4-dihydro

pyridine

54.0 g of dodecyl acetoacetate, 10.5 g of hexamethylenetetramine, 2.9 g of ammonium acetate, 6.5 g of methanol and 8.0 g of water are introduced into a reactor.

While stirring, the temperature of the reaction medium is raised in 45 min until reflux of methanol and the reflux is maintained for 1 h. The suspension is allowed to cool to room temperature and poured into a mixture of 300 g of water and ice (50/50). The mixture is stirred for 1 hour to remove the excess hexamethylenetetramine. It is filtered and the product is taken up in 300 g of water. Stirred, then filtered again and the product is finally recrystallized from 400 g of acetone.

2,6-dimethyl-3,5-dicarbododecyloxy-1,4-dihydro-pyridine is obtained with a yield of 73.5%.

Melting point: 96 ° C.

By proceeding in the same way, the following products were prepared:

Acetoacetate used

Dihydro-1,4 pyridines I

R

Rdt

(%)

Recrystallization solvent

PF (° C)

Phenyl acetoacetate

0

1

4

Dimethylformamide

239

P-tolyl acetoacetate

-O "™ 1

32

Ethanol / acetone 90/10

214

P-anisyl acetoacetate

-O-0 ™ 1

34

Acetone

184 then 195

P-chlorophenyl acetoacetate

-0-it

14

Acetone

227

Decyl acetoacetate Tetradecyl acetoacetate

- (CH2) 9CH3 - (CH2) 13CH3

64

65

Acetone Acetone

95

96

641780

6

Acetoacetate used

Dihydro-1,4 pyridines I

R

Yield (%)

Recrystallization solvent

PF (° C)

Octadecyl acetoacetate

- (CH2) 17CH3

78

103

-CH2- (CH2) 7-CH

Octadecen-yl acetoacetate

II

91.9

56

CH3- (CH2) 7-CH

Docosanyl acetoacetate

- (CH2) 21CH3

75.6

106

The last of these compounds is in the form of a yellow pasty product, while the previous two are in the form of a yellow powder.

Example 4:

1,4-dihydro-pyridines derived from mixtures of industrial, natural or synthetic alcohols have also been prepared. These compounds are listed below.

Alkyl acetoacetate used

Dihydro-1,4 pyridines I

R

PM

way

Yield (%)

Aspect

PF (° C)

Raw tridecyl acetoacetate

(Alcohol: Acropolis 35)

CH3 (CH2) n— n = 11 to 14

574

76

Yellow-green powder

89

Raw tridecyl acetoacetate

(Alcohol: Dobanol 23)

CH3 (CH2) n— n = 11 or 12

572

45.4

Yellow powder

89

Raw tridecyl acetoacetate

(Alcohol: Dobanol 25)

CH3 (CH2) n— n = 11 to 14

595

78

Yellow-green powder

89

Raw oleocetyl acetoacetate

(Alcohol: H.D. Océnol)

CH3— (CH2) iS - CH3 (CH2) 7CH = CH (CH2) n n = 6 to 8

675

41

Yellow powder

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2. Properties of the products

For the sake of simplification, reference will be made to the main compounds of formula I studied by designating them by their code number shown in table I.

Table I (continued)

Table 1

RO-H

0 II

HORN

H

XX

»C N CH-

K

R

Code no.

—Ch2 — ch3

L. 28501

- (ch2) 7 — ch3

L.28502

3

1

L. 28504

R

Code no.

50

-ch

L. 28506

ch3

- (ch2) u — ch3

L.28507

55

-o

L. 28508

- (ch2) 2ch3

L. 28509

-c (ch3) 3

L.28510

60

0

1

L. 28531

o-

L. 28538

65

-o—.

L. 28541

oh

1

Q

L. 28551

7

641,780

Table I (continued)

R

Code no.

- (CH2) 3CH3

L.28552

- (CH2) I3CH3

L.28590

- (CH2) 9-CH3

L. 28591

- C12H25 to —Ci5H31 *

L. 28596

- (CH2) n-CH3

with n = 11 or 12 **

L.28597

n - 11 to 14 ***

L.28598

- (CH2) 17-CH3

L.28599

f - CH2 - (CH2) 7 - CH = CH - (CH2) v - CH3 **** 1- (CH2) 1s-CH3

L.28600

- (CH2) 2I — CH3

L. 28601

- (CH2) 8 - CH = CH— (CH2) 7 - CH3

L. 28602

* Acropolis 35 Ci2-C15. 20

** Dobanol 23 C12-C13.

*** Dobanol 25 C12-Cls.

**** H.D. Océnol C] 6-C18.

The toxicity of the light stabilizers according to the invention was first determined and the satisfactory results obtained made it possible to continue the study.

2.1 Study of acute toxicity

The acute toxicity of the compounds according to the invention was studied by determining the dose of product causing 50% death in the treated animals (DLS0).

The determination was made by oral administration of a gummy suspension of the compounds to batches of at least 10 mice or 10 rats. 35

The results observed show that, for these two animal species, the LD50 is, for the molecules, greater than 2 g / kg and often greater than 5 g / kg.

Furthermore, no toxic symptoms were observed after 15 days of observation. 40

2.2 Study of migration

The migration or extractability of the stabilizer from the PVC compound under the effect of various liquids (and in particular water) packaged in plastic packaging is of vital importance for the use of these stabilizers in the field. food packaging. The study of the migration of dihydropyridines I into water has been deepened compared to 2-phenyl indole chosen as the reference molecule.

The extractability technique was as follows: a batch of bottles (volume 11, diameter 70 mm, height ~ 230 mm) was prepared, with the formula given below, which were filled with a liquid simulating the food. Under these conditions, the volume / surface ratio (volume of liquid / surface of the bottle in contact) is close to 1.85. The migration of the stabilizer was judged by assaying the pyridine present in the extractum according to the assay method described below. This pyridine obviously represents the oxidized form of the 1,4-dihydro-pyridine extracted.

The study was particularly developed for water at 50 ° C over a period of 2 months, because it represents the important problem of packaging mineral waters.

2.2.1 Formula for the manufacture of bottles

Ingredients Parts by weight

Poly (vinyl chloride) resin 100

Shockproof agent 8

Epoxidized soybean oil 4

Acrylic resin 0.5

Trinonylphenylphosphite 0.3

SL 2016 0.25

Calcium behenate 0.4

Glycerol trimontanate 0.4

Hydrogenated castor oil 1,2

Stabilizer 0.015 to 0.5

SL 2016 is a solution of 2-ethylhexanoate of zinc in a mixture of aromatic hydrocarbons boiling from 158 to 184 ° C.

2.2.2 Assay method

The stabilizers are dosed in the form of their oxidation product (pyridine).

Oxidation is made quantitative by adding a few drops of iodine to the solution. Then it is extracted with chloroform and the chloroform is evaporated to a small residual volume. A thin layer chromatography of the solution obtained is then carried out, in comparison with solutions of known concentration of the desired pyridines.

The sensitivity threshold for this technique is 5 (j.g / 1.

2.2.3 Results of the extractability study

This study was carried out on the following compounds: Dimethyl-2,6 di (carbomethoxy) -3,5 dihydro-1,4 pyridine (L. 28504) Dimethyl-2,6 di (carboethoxy) -3,5 dihydro-1 , 4 pyridine (L. 28501) Dimethyl-2,6 di (carbobutoxy) -3,5 dihydro-1,4 pyridine (L. 28552) Dimethyl-2,6 di (carbododecyloxy) -3,5 dihydro-1,4 pyridine (L. 28507) Dimethyl-2,6 di (carbotetradecyloxy) -3,5 dihydro-1,4 pyridine (L. 28590)

Dimethyl-2,6 di (carbooctadecyloxy) -3,5 dihydro-1,4 pyridine (L. 28599)

Stabilizing

Migration (dd.g / 1) at 50 ° C

Extraction medium

Nature -

Concentration in per

10 d

20 d

1 month

2 months

L.28507

0.15

<5

<5

<5

<5

Water

L.28507

0.30

<5

<5

<5

<5

Witness*

0.30

75

90

100

100

L.28590

0.15

<5

<5

<5

<5

L.28590

0.30

<5

<5

<5

<5

Witness

0.30

75

90

110

110

L.28599

0.15

<5

<5

<5

<5

L.28599

0.30

<5

<5

<5

<5

Witness

0.30

70

90

120

130

* Phenyl-2 indole.

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It emerges from this study that:

- dihydropyridines are much less extractable than 2-phenyl indole,

The stabilization of the vinyl resins by the dihydropyridines according to the invention requiring concentrations which are far lower than those required by the 2-phenyl indole, there follows an even greater reduction in migration,

- in the series of 1,4-dihydro-pyridines I for which R contains from 9 to 22 carbon atoms, the migration into water changes according to the number of carbon atoms forming the radical R of formula I, this in parallel to sublimation as we will see later,

- for values of R comprising from 9 to 22 carbon atoms, and in particular for R = 12.14 and 18 carbon atoms, the migration into water is less than 5 ng / 1, whatever the concentration of the stabilizer in the PVC compound between 0.01 and 0.5 per. In fact, migration should be significantly less than

5 (j.g / 1, but this estimate is limited to this value by the sensitivity threshold of the assay technique.

We can conclude that the dihydropyridines I whose radical R varies between 9 and 22 carbon atoms can be used for the stabilization of PVC intended for the conditioning of mineral waters, whereas those in which R varies between 1 and 8 carbon atoms do not are not due to their migration too high.

To justify the possibility of using dihydropyridines I having a radical R comprising from 9 to 22 carbon atoms in applications relating to food packaging other than those relating to mineral waters, the extractability of dihydropyridines has been studied by several solutions or solvents having the following composition, by weight:

at)

water / sodium chloride

- 97/3

b)

water / sucrose

90/10

vs)

water / sodium chloride / acetic acid

98.5 / 0.5 / 1

d)

water / citric acid (solution at pH = 5)

98/2

e)

water / acetic acid

97/3

f)

water / acetic acid

90/10

g)

water / ethanol

85/15

h)

water / acetic acid

50/50

i)

water / ethanol

50/50

j)

pure heptane

50/50

The results obtained are reported in the tables below:

Migration (j-ig / 1)

Extraction medium

Stabilizers 0.3 per

at 50 ° C

1 month

2 months

2-phenyl indole

90

140

H20 / NaCl (97/3)

L. 28504 * L. 28507

100

<5

120 <5

L. 28590

<5

<5

L.28599

<5

<5

Water / sucrose

L. 28504 *

100

110

(90/10)

L. 28507

<5

<5

Water / NaCl / CH3COOH

L. 28504 *

110

120

(98.5 / 0.5 / 1)

L.28507

<5

<5

Water / citric acid **

L. 28504 *

90

120

(97/3)

L.28507

<5

<5

Water / CH3COOH

L.28504 *

120

140

(90/10)

L.28507

<5

<5

Extraction medium

Stabilizers 0.3 per

Migration (ng / 1) at 50 "C

1 month

2 months

Water / CH3COOH (50/50)

L.28504 * L.28507

150 25

200

Water / C2H5OH (50/50)

L. 28504 * L. 28507

250 50

-

Stabilizers 0.3 per

Migration (| ig / l) at 50 ° C

after 36 h after 84 h

Heptane

L.28504 * L.28507

300 120

390 150

* Comparison: R = - CH3.

** The pH of this solution is adjusted to 5 with aqueous sodium hydroxide.

It emerges from these results that the dihydropyridines I in which R comprises from 9 to 22 carbon atoms, and in particular those in which R comprises 12,14 and 18 carbon atoms, give for the solutions a, b, c, d, e, f and g a migration of less than 5 jxg / 1 of solution. Under the same conditions, the first terms of the dihydropyridine series I and in particular that of which the radical R = —CH3, give migrations of the order of 80 to 100 fj.g / 1 comparable to those of 2-phenyl indole.

For solutions h, i and j, the dihydropyridines I in which R comprises from 9 to 22 carbon atoms also give better results than their lower counterparts and 2-phenyl indole.

2.3 Study of sublimation

Sublimation of the stabilizer is to be taken into account in the context of the protection of the health of the personnel of the workshops where the stabilizer is manufactured or used. In other words, it is a matter of occupational safety.

In this regard, it was found that:

- The sublimation of 1,4-dihydro-pyridines is not only linked to molecular weight. We have noticed in fact that, contrary to what we can expect, the derivative I for which

R = - CH3 sublimes markedly less than dihydropyridines I having a heavier R radical such as ethyl, propyl, isopropyl, butyl, etc.

Thus, under the operating conditions used to judge the sublimation of the products of this series, the 2-phenyl indole chosen as the reference molecule sublimes at the rate of 62% of the amount of product used. Under the same conditions, the derivative I for which R = - CH3 (methyl), sublimes at 34% and the higher homologs (ethyl, propyl, isopropyl, butyl, etc.), at a higher percentage of between 35 and 98 %.

- Sublimation is important for the values of R representing 1 to 8 carbon atoms, whether these radicals are linear or branched, saturated or unsaturated. Under the operating conditions described below, the quantity of sublimed product is between 10 and 98%. It drops to 7% for R = linear octyl, which again represents a significant sublimation.

- Sublimation becomes weak, that is to say equal to or less than 3%, from the radical with 9 carbon atoms and, more particularly, from the radical comprising 10 carbon atoms.

- The sublimation of dihydropyridines I having a radical R comprising from 10 to 22 carbon atoms is very low (in any case less than 2%), sometimes zero for saturated linear radicals comprising 12,14,16, 18, 22 atoms of carbon and for radi-

8

5

10

15

20

25

30

35

40

45

50

55

60

65

9

641,780

linear and unsaturated waters such as the oleyl chain. These observations are valid for mixtures of these different dihydropyridines (example R = oleocetyl radical).

- Sublimation of dihydropyridines I having a radical R derived from synthetic alcohols available on the market such as Acropole 35, Dobanol 23, Dobanol 25 (linear or branched synthetic alcohols comprising from 12 to 15 carbon atoms)

remains low (2 to 3%), but higher than that of linear radicals. These synthetic alcohols indeed contain a significant portion of branched alcohols in position a since they are prepared by oxo reaction on linear olefins.

This last observation clearly shows that the problem of sublimation is not linked only to the molecular mass of the dihydro-pyridine I concerned, but also to its structure. In particular, with an equal or comparable molecular mass, a linear R radical seems to lead to lower sublimation than a branched R radical.

The figures justifying these observations are reported below.

Sublimation results

2.3.1 Procedure:

A test sample close to 130 mg of the product to be studied is introduced into a 100 cm3 beaker. The whole is placed in a 250 cm3 reactor. The temperature is maintained at 160 ° C. using an oil bath thermostatically controlled for 6 h, the atmosphere of the reactor being inert (nitrogen) to avoid the oxidation of 1,4-dihydro-pyridine to pyridine which is more sublimable.

2.3.2 Results:

For each dihydropyridine derivative studied, the result is expressed as a percentage of sublimed product relative to the amount involved.

Product

% of sublimated pdt

2-phenyl indole

62

ch3 -c2hs

-n-C3H7

34.2 82.9 79.1

Dihydropyridines of formula I with R meaning

.ch,

-ch ^

ch3

comparison

98.1

- (ch2) 3-ch3 - (ch2) 7-ch3

>

f

39.2 7.2

- (ch2) 9-ch3 - (CH2) u —ch3 - (ch2) 13 —ch3 - (ch2) l7 — ch3 - (ch2) 21 — ch3 ch3— (ch2) n— * n = 11 to 12

1.7 1.7 0.1 1.2 0.4

3.1

ch3— (ch2) n— ** n = 11 to 14

3.1

c12h25c to 15h31 ***

| ch3 (ch2) 7 - ch = ch - (ch3 (ch2) 15- n = 6-8

(ch2) n— ****

3.2 1.7

* Prepared from Dobanol 23.

** Prepared from Dobanol 25.

*** Prepared from Acropolis 35.

**** Prepared from H.D. Océnol.

2.4 Study of the light-stabilizing power

A comparative study of the photostabilizing power of the compounds of the invention was carried out by exposing to the sun poly (vinyl chloride) plates which differ only in the stabilizer used.

The two reference stabilizers were:

- (methoxy-3 'hydroxy-4' phenyl) -2 indole (S. 3630),

- 2-phenyl indole (S. 3621).

Example 5:

Two poly (vinyl chloride) compositions were prepared, according to the following formula:

Ingredients Parts by weight

Poly (vinyl chloride) resin 100

Ingredients

Parts by weight

Shock resistant resin

8

Epoxidized soybean oil

4

Acrylic resin

0.5

Trinonylphenyl phosphite

0.3

SL 2016

0.25

Calcium behenate

0.4

Hydrogenated castor oil

0.2

Glyceryl trimontanate

0.4

Stabilizing

0.2

The stabilized poly (vinyl chloride) sheets have been prepared

rees by mixing on a cylinder at 160 ° C and were exposed to the sun under the same conditions.

Their coloration was evaluated in two different ways, after 6 65 and after 12 h of sun exposure:

- on the plates themselves compared to the Gardner scale, described in French patent No. 2273841,

- on a solution of these plates in tetrahydrofuran

641780

10

compared to the range described in the “French Pharmacopoeia” (IXth edition, II, 338).

The results obtained are shown in the table below:

Color of

Color of

plates according

plates according to the

Stabilizers

Gardner

"Pharmacopoeia"

Exposure time

Exposure time

0

6 a.m.

12 noon

0

6 a.m.

12h

S 3630

1

4

8

B5

B4 to JB4

B3 to JB3

S 3621

2

3

6

D6

D5

D4

J28504

1

1

1.5

JV6

JV6

JV6

L 28501

1

1

1.5

JV6

JV6

JV6

Ingredients Parts by weight

Solvic 223 90 resin

Copolymer IXAN SGA 1 10

Reinforcing agent BTA III 8

Epoxidized soybean oil 4

0.2 calcium stearate

Zinc stearate 0.1

Lubricant 4,146 1.2

Lubricant 6,164 0.4

Stabilizer 0.3

Lubricant 4146 is a hydrogenated castor oil and lubricant 6164 glyceryl trimontanate.

Four other molecules were tested (R = n-C10H22 (L. 28591); n-C12H25 (L. 28507); -C14H29 (L. 28590); -C18H37 20 (L. 28599)) compared to the molecules studied above. above (R = —CH3; R = - C2Hs) using the same formula and with 0.2 per cent stabilizer.

The color development of the stabilized PVC was judged in the same way. 2s

The results observed show a comparable photostabilizing power between these different dihydropyridines whatever the molecular mass.

Similar tests have been performed on various copolymer formulas. 30

Example 6:

Comparison of dihydropyridines according to the invention (abbreviated as DHP) to 2-phenyl indole

Flexible vinyl copolymer formula, 35

vinyl chloride / vinyl acetate copolymer.

Ingredients Parts by weight

Lucovyl SA 6001 100

Dioctyl phthalate 40

Calcium stearate 2 40

Melamine 2

Wax E 1

Stabilizer 0.3

Time (h) Stabilizer

Coloring (Gardner degrees)

at time 0

after 120 h

2-phenyl indole

1.5

17

L.28504

1.5

4

L.28507

1.5

4

Example 7:

Comparison of DHP with 2-phenyl indole Rigid vinyl copolymer formula,

vinyl chloride / vinylidene chloride copolymer.

Example 8:

Comparison of DHP with 2-phenyl indole Rigid vinyl copolymer formula,

vinyl chloride / vinylidene chloride copolymer.

Ingredients

Solvic 223 PVC resin IXAN SGA / 1 copolymer BTA III reinforcing agent Epoxidized soybean oil Calcium stearate Zinc stearate Lubricant 4146 Lubricant 6164 Stabilizer

Parts by weight

90 10 8 4 0.2 0.1 1.2 0.4 0.3

Test

Time (h) Stabilizer

Coloring (Gardner degrees)

at time 0

after 24 h

AT

Phenyl-2 indole L. 28504 L. 28591 L. 28541 L.28599 L.28601 L.28602

1 1 1 1 1 1 1

6 1 1 4 1 1 1

2-phenyl indole

1

8

L. 28507

1

1

B

L. 28502

1

1

L. 28506

1

2

L. 28508

1

2

Time (h)

Coloring (Gardner degrees)

Stabilizing at time 0

after 24 h

2-phenyl indole

1

13

L. 28597

1

2

L.28601

1

2

L. 28541

1

3

D0 Example 9:

Comparison of DHP with 2-phenyl indole Rigid vinyl copolymer formula,

vinyl chloride / vinylidene chloride copolymer.

Formula: identical to that of Example 8, but with a variable concentration-55 tration x while stabilizing.

65

Time (h)

Concentration x (parts)

Coloring (Gardner degrees)

Stabilizing at time 0

after 24 h

2-Phenyl indole L.28504 L.28507

0.3 0.3 0.3

1 1 1

13 2 2

L. 28504

0.15

1

2

L. 28507

0.7

1

2

11

641,780

The results of Example 9 prove, with the variations in concentration of the products L. 28504 and L. 28507, that the copolymers in which they are incorporated are stable to light. Indeed, variations in concentration of 0.15 to 0.7 per do not seem to have an influence on the light fastness of the copolymers.

2.5 Study of the heat-stabilizing power 2.5.1 Static thermostability

Static thermostability was studied according to the method described in French patent No. 2273841, 2-phenyl indole being the reference substance.

The stabilizer is incorporated, with other usual additives, in a powdered polyvinyl chloride resin. A rigid sheet is formed by calendering the mixture at 160 ° C. and this sheet is subjected to stays of variable duration in an oven at fixed temperature (185 or 210 ° C.) until the start of carbonization.

The coloration of the samples is then compared with the Gardner coloration scale.

The study was carried out with the resins below:

Example 10:

Ingredients

Poly (vinyl chloride)

Shock Resin Epoxidized Soybean Oil 2-Hydroxy Calcium Stearate SL 2016 Stabilizer

Parts by weight

100 9 2 0.2 0.1

0.3 or 1.55 x 10 3 mol

Stabilizing

Time (min)

0

3

6

9

12

15

18

L.28501

1

1

2

2

4

8.5

B

L. 28506

1

1

2

5

11

19

B

L. 28507

1

1

2

6

8

19

B

L.28508

1

1

3

5

14

B

L. 28509

1

1

2

4

4

17

B

L.28510

1

1

4

5

15

B

L.28504

1

1

2

3

7.5

19

B

2-phenyl indole

1

2

2

10

11

16

B

L.28504

1

1

1

3

7

B

2-phenyl indole

1

1

2

4

13

17

B

L.28538

1

1

3

3

4

14

B

L. 28541

1

1

1.5

3

5

11

B

L.28504

1

1

1

2.5

3

11

B

2-phenyl indole

1

2

2

3

6

14

B

L.28552 1 L.28504 1 Phenyl-2 indole 1

1 1 1

2 2 2

4 3 6

11

8

14

12 10 14

B B B

The results below were obtained after steaming at 210 ° C a resin containing 0.3 parts of stabilizer:

The above results show the clear superiority of the dihydropyridines of the invention over 2-phenyl indole.

Tests were also carried out at 185 ° C., with a resin containing 0.3 parts of stabilizer and the results obtained are given in the table below:

Time (min)

p. 1 * 1 * t

otaDiiisants

0

6

12

18

24

27

30

33

36

39

42

L. 28501

1

1

2

8

11

13

13

18

B

L. 28531

1

1

3

7

10

10

10

16

B

L. 28538

1

1

3

10

13

13

14

17

17

B

L. 28504

1

1

2

7

11

11

11

13

B

2-phenyl indole

1

1

3

5

13

13

14

14

15

15

B

L.28506

1

1

3

3

6

12

13

14

15

15

17

L.28508

1

1

3

5

8

13

16

18

18

18

18

L. 28509

1

1

2

3

5

9

9

11

13

14

15

L.28510

1

1

2

4

10

18

18

19

19

B

L. 28504

1

1

1

2

4

7

7

8

10

11

15

2-phenyl indole

1

1

3

5

10.5

13

14

14

14

14

14

L.28507

1

2

7

11

13

14

15

15

18

B

L.28504

1

1

2

3

5

7.5

8.5

9

14

B

2-phenyl indole

1

1

4

9

13

14

14

14

14

15

15

L. 28502

1

1

2

3

4

6

7

8.5

9

11

15

L. 28504

1

1

2

3

4

7

7

8

9

11

14

2-phenyl indole

1

1

3

9.5

11

14

14

14

14

14

14

The above results also show the manifest superiority of the dihydropyridines according to the invention over 2-phenyl indole.

In addition, tests were carried out at 185 ° C. with resins containing equimolecular amounts of stabilizer, namely 1.55 × 10 −3 mol, and the results were obtained below.

(Table at the top of the next page)

We also note the superiority of dihydropyridines over phenyl-2 indole when they are used in the same molecular quantity as the latter.

Similar tests have been carried out on derivatives of hydro-pyridines in which the R chain contains more carbon atoms.

641780

12

Stabilizing

Weight of

Time (min)

stabilizing

0

6

12

18

24

27

30

33

36

39

42

L. 28501

0.4

1

1

1

5

10

11

B

L.28531

0.5

1

1

2

5

8.5

10.5

11

16

B

L. 28538

0.6

1

1

2

7

7

9

10

17

B

L. 28541

0.6

1

1

2

7

9

9

10

16

B

L.28504

0.35

1

1

1

4

5

8

11

15

B

2-phenyl indole

0.3

1

2

3

10

13

13

13

14

16

16

B

We used the formula below: Ingredients

PVC resin (Solvic 223)

Shock resistant resin

Epoxidized soybean oil

SL2016

SS 32

Stabilizing

Quantity of stabilizer in the formula: 0.3 per

Parts by weight

100 9 2 0.1 0.2

x (x = 0.1 to 0.3 per)

30

The SS 32 product is calcium hydroxystearate.

The experimental methods described above were used to obtain the stability bands and to examine them, using the stability test at 210 ° C, in an oven.

In equal quantities, the various dihydropyridines I give comparable results, whatever the value of the radical R. The fact of increasing the molecular mass of I does not lower its heat-stabilizing power and concentrations varying from 0.01 to 0, 5 per, and especially from 0.01 to 0.2 per, lead to very valid results. 40

The results obtained are expressed below.

45

Stabilizing time (min)

0

3

6

9

12

15

L.28597

1

1

1

2

4

7

L.28598

1

1

1

2

4

13

L. 28596

1

1

1

2

4

13

L.28599

1

1

1

2

4

13

L.28600

1

1

1

2

5

13

2-phenyl indole

1

1

2

4

11

14

^ ~ \ Time (min) Stabilizing

0

3

6

9

12

L. 28601

1

1

2

2

4

L.28507

1

1

2

2

3

2-phenyl indole

1

1

2

4

10

Quantity of stabilizer in the formula: 0.2 per

^^ Time (min) Stabilizer n.

0

2

4

6

8

10

12

14

L. 28597

1

1

1

2

3

3

11

11

L.28598

1

1

1

2

3

3

11

15

L.28596

1

1

1

2

3

3

11

13

L.28599

1

<2

<2

2

3

3

10.5

14

L.28600

1

<2

<2

2

<3

<3

10.5

14

2-phenyl indole

1

1

1

2

3

4

12

15

13

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

L. 28502

1

1

1

2

2

3

5

L.28590

1

1

1

2

2

3

7

L.28591

1

1

1

2

2

3

8

L.28507

1

1

1

2

2

3

7.5

2-phenyl indole

1

1

1

2

2

5

9

Quantity of stabilizer in the formula: 0.1 per

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

L.28502

2

2

2

2

3

6

11

L.28590

2

2

2

2

2

4

10.5

L. 28591

2

2

2

2

2

4

10.5

L.28507

2

2

2

2

3

4

10.5

2-phenyl indole

2

2

2

3

4

11

13

641,780

2.5.2 Stabilization of resins intended for the conditioning of mineral waters

The tests were carried out as follows:

- a resin containing, in addition to the stabilizer to be tested, calcium and zinc stearates and epoxidized soybean oil was kneaded on a roller mixer and the initial color stability was observed, this is that is to say that the time elapsing between the start of the mixing and the first visible change in the coloring of the resin has been measured; the thermal stability of the resin was also observed, that is to say that the time elapsing between the start of kneading and the degradation of the resin was measured,

- The same resin was passed through an extrusion-blowing machine and the development of the coloring of the resin was observed at each of the three passages on the machine.

For this extrusion-blowing operation, the following characteristics were retained:

Temperature: 165, 160,165,160,180 ° C.

Screw speed: 60 rpm.

Die: air gap: 1.5 mm, land: 55 mm.

Mold: cylindrical bottle of 250 cm3.

Four resins, numbered from 1 to 4 and containing respectively 0.2 part of 2-phenyl indole, 0.2, 0.03 and 0.015 part of the compound L. 28504, were tested and the following results were obtained:

Mixing at 220 ° C

Resin

1

2

3

4

Color stability

(min)

Thermal stability (min)

3 13

6

13.5

3

12.7

2

12.3

Bottle color at

1st pass

Sky blue

Sky blue

Sky blue

Sky blue

shiny shiny shiny

2nd pass

Attenuated blue

Sky blue

Sky blue

Sky blue

towards green brilliant brilliant brilliant

3rd pass

Blue

Sky blue

Sky blue

Sky blue

greenish shiny shiny shiny

It can be seen that 2,6-dimethyl-3,5-dicarbomethoxy-1,4-dihydro-pyridine gives the resin more color stability. The same tests were carried out, but with a resin containing dif-labeled as phenyl- 2 indole, even at a rate of 0.015 per. different proportions of calcium and zinc stearate.

Stabilizing

Resin number

Amount of stabilizer

1

2

3

4

5

6

7

8

9

Calcium stearate

0.29

0.29

0.29

0.29

0.29

0.29

0.29

0.29

0.15

Zinc stearate

0.32

0.32

0.32

0.32

0.32

0.32

0.15

-

0.32

2-phenyl indole

0.15

L.28504

-

0.15

-

0.075

0.05

0.015

0.15

0.15

0.075

641780

14

The following results were obtained:

Mixing at 220 ° C

Resin

1

2

3

4

5

6

7

8

9

Color stability (min) Thermal stability (min)

2 to 3 9

5 9

4

8.5

4

8.5

3

8.5

3

8.5

3

15.5

1 7

3 5

As in the previous test, the compound L. 28504 improves the color and the stability. Compound L. 28504 has been shown to be 10 to 15 times more effective than 2-phenyl indole.

In formula No. 2, the compound L. 28504 does not have a direct influence on the thermal stability, but it makes it possible, by preserving the shade, to reduce the level of zinc stearate, which can cause the appearance of defects in the resin.

As regards the examination of the coloration of the resin after each pass on the extruder-blower, the excellent behavior of the resins containing the compound L. 28504 was noted.

2.5.3 Stabilization of plasticized resins

Poly (vinyl chloride) sheets previously pressed for 5 min at 170 ° C. were pressed for 5 min at 180 ° C. and the color stability and the thermal stability after mixing were observed, followed by the coloring of the plates. after pressing.

The resin retained contained, as adjuvants, in addition to the stabilizer to be tested, wax E, dioctyl phthalate, barium stearate and cadmium stearate in the proportions below:

20

Ingredients

, —Resin number

Quantities

1

2

3

4

5

6

7

8

9

Polyvinyl chloride resin

100

100

100

100

100

100

100

100

100

Wax E

0.3

0.3

0.3

0.3

0.3

0.3

0.3

0.3

0.3

Dioctyl phthalate

50

-

50

50

50

50

50

50

50

Barium stearate

-

0.375

-

0.375

0.375

0.375

0.375

0.375

0.375

Cadmium stearate

-

-

0.375

0.375

0.375

0.15

0.15

0.05

0.05

Compound

-

-

-

-

0.1

-

0.05

-

0.05

The following results were obtained:

Mixing at 180 ° C

1

2

3

4

5

6

7

8

9

Color stability (min)

25

25

25

35

50

30

45

20

35

Thermal stability (min)

25

5

25

35

50

30

55

25

50

Pressing at 170 ° C

Shade of the pressed plate

-

-

Pinkish

Very little

Pinkish

Very little

Reddish

Yellowish

(thickness 3 mm)

yellowish

yellowish

Finally, we studied the thermal stabilization of vinyl copolymers with dihydropyridines.

Example U:

Rigid copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients Lucovyl MA 6035 Lucovyl MB 1000 Stabilizing calcium stearate

Stability examination in a ventilated oven at 185 ° C.

50

Parts by weight 55

80 20 0.5 0.3

60

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

14

L. 28599

1

1

3

6

10

14

16

17

L.28601

1

1

4

9

11

14

16

17

L.28602

1

1

4

9

12

16

17

18

L.28502

1

1

3

6

10

13

14

18

Time (min)

0

2

4

6

8

10

12

14

Stabilizing

6b

No stabilizer

1

2

4

7

13

16

17

18

Note: The colors expressed in Gardner degrees are favorable to the formulas stabilized by the dihydropyridines according to the invention. However, in reality, the figures only inadequately reflect the differences, since the unstabilized copolymer shows, from time zero, a relatively intense coloration which is difficult to quantify in the Gardner scale.

15

641,780

Example 12:

Rigid copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients Parts by weight

Lucocyl MA 6035 80

Lucovyl MB 1000 20

Calcium stearate 0.5

Stabilizer 0.1

Stability examination in a ventilated oven at 185 ° C.

^ \ Stabilizing time (min)

0

10

20

30

40

50

60

Without stabilizer

1

1

5

8

12

13

13

L. 28504

1

1

2

6

8

10

12

L.28507

1

1

2

6

8

10

12

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

14

No stabilizer

1.5

2

4

11.5

15

17

18

18.5

L.28504

1

1

4

6

11

11

12

13

L. 28507

1

1

4

10

12

13

15

-

L. 28597

1

1

4

10

12

15

17

-

The remark made with regard to example 11 is also valid.

Example 13:

Flexible copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients

Lucovyl MA 6035 Dioctyl phthalate Melamine Calcium stearate Stabilizer

Parts by weight

100 60 2 2 0.2

Gelation: 5 min at 120 ° C.

Passage in a Metastast oven at 160 ° C: duration 60 min flow rate 50 1 / h

^ \ Stabilizing time (min)

0

30

40

50

60

Without stabilizer

1

6

13

14

17

L. 28504

1

1

2

4

12

L.28507

1

2

6

12

15

Example 14:

Flexible copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients

Lucovyl SA 6001 Dioctyl phthalate Calcium stearate Melamine Stabilizer

Parts by weight

100 40 2 2 0.3

20

Example 15:

Rigid copolymer formula,

vinyl chloride / vinylidene chloride copolymer.

Ingredients Parts by weight

Solvic 223 90

IXAN SGA / 1 10

Reinforcing agent BTA III 8

Epoxidized soybean oil 4

0.2 calcium stearate

Zinc stearate 0.1

Lubricant 4,146 1.2

Lubricant 6,164 0.4

Stabilizer 0.3 Passage in a ventilated oven at 210 ° C.

^^ \ Time (min) Stabilizing

0

3

6

9

12

15

Without stabilizer

2

2

5

10.5

14

16

L.28504

1.5

1.5

2

3

10

13

L. 28507

1.5

1.5

3

4

12.5

15

40

The remark made with regard to example 1 is also valid.

Example 16:

Rigid copolymer formula,

vinyl chloride / vinylidene chloride copolymer.

Ingredients

Solvic 223 IXAN SGA / 1 Reinforcing agent BTA III Epoxidized soybean oil Calcium stearate Zinc stearate Lubricant 4146 Lubricant 6164 Stabilizer

Passage in a ventilated oven at 210 ° C.

Parts by weight

90 10 8 4 0.2 0.1 1.2 0.4 0.3

Passage in a Metrastat oven at 160 ° C: duration 60 min flow rate 501 / h

^ \ Stabilizing time (min)

0

3

6

9

12

Without stabilizer

1.5

2.5

4.5

11

14

L.28597

1

1

2

4

12.5

L. 28601

1

1

2

5

13.5

641,780

16

The remark made with regard to example 11 is also valid.

The dihydropyridines of formula I (DHP) were compared with the β-aminocrotonates of alcohols and polyols.

Time (min)

Stabilizing

0

2

4

6

8

10

12

Examples 17 to 29 below show the superiority of the heat-stabilizing power of 1,4-dihydro-pyridines of formula I over that of β-aminocrotonates.

methyl ß-aminocrotonate

1

1

5

12

14

17

18

Example 17:

L. 28504

1

1

1

5

8

11.5

13.5

with methyl ß-aminocrotonate

Rigid copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients

Lucovyl MA 6035 Lucovyl MB 1000 Stabilizing calcium stearate

Passage in a ventilated oven at 185 ° C.

Parts by weight

80 20 0.5 0.5

Example 18:

Comparison of DHP with stabilizer G, (stabilizer G, is a commonly used mixture of 1,4-butanediol bis-ß-aminocrotonate and C16-C18 alcohol ß-aminocrotonates)

Rigid vinyl copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Time (min)

0

2

4

6

8

10

12

Stabilizing

25

ß-aminocrotonate

1,4-butanediol

1

1

4

10

13

15

18

Ingredients Solvic 547 SA resin Lacqvyl S-071-S resin Calcium stearate Irgawax 280 Stabilizer

Passage in a ventilated oven at 185 ° C.

Parts by weight

80 20 0.5 0.1 0.3

^ \ Stabilizing time (min)

Amount of stabilizer (parts)

0

2

4

6

8

10

12

14

Gj stabilizer

0.3

1.5

1.5

2

3.5

4

12.5

15

18

L. 28504

0.3

1

1

1

2

3

4

7

13

L.28507

0.3

1

1

2

2.5

4

7

10.5

17

Example 19:

Comparison of DHP with Gj stabilizer Formula rigid vinyl copolymer, vinyl chloride / vinyl acetate copolymer.

Ingredients

Lucovyl MA 6035 Lucovyl MB 1000 Calcium stearate Gx or DHP stabilizer

Passage in a ventilated oven at 185 ° C.

Parts by weight

80 20 0.5 0.5

45

Example 20:

Comparison of DHP with stabilizer G,

Rigid vinyl copolymer formula, vinyl chloride / vinyl acetate copolymer.

50

Ingredients Lucovyl MA 6035 Lucovyl MB 1000 Stabilizing Calcium Stearate G, or DHP

Passage in a ventilated oven at 185 ° C.

Parts by weight 80 20 0.5 0.5

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

Stabilizer G!

1

1

4

11

12.5

16

18.5

L.28501

1

1

2

7

12

15

-

L.28504

1

1

1.5

6

9.5

13

17

60

65

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

Gì stabilizer

1

1

2.5

11

13.5

17

18.5

L. 28597

1

1

2

3

11

13

-

L. 28599

1

1

2.5

3

11

15

-

L.28601

1

1

3

6

13

17

-

17

641,780

Example 21:

Comparison of DHP with stabilizer Gi Formula rigid vinyl copolymer, vinyl chloride / vinyl acetate copolymer.

Ingredients

Vinnol H 13/50 S Glyceryl tribhenenate Calcium stearate Stabilizer G! or DHH

Stability in ventilated oven at 185 ° C.

Parts by weight

100 0.4 0.5 0.5

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

14

L.28599

1

1

4

6

10

11

12.5

-

L. 28601

1

1

4

6

10

11

13

-

L. 28501

1

1

2

4

10

11

14

-

L. 28506

1

1

2

6

10

12

14

-

^ \ Time (min)

0

2

4

6

8

10

12

14

Stabilizing

Stabilizer G]

1

2

3

4

9

12

18

-

L.28504

1

1

2

3

4

11

18

-

Example 24:

Comparison of DHP with stabilizer G,

Rigid vinyl copolymer formula, vinyl chloride / vinyl acetate copolymer.

Example 22:

Comparison of DHP with stabilizer G,

Rigid vinyl copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients Parts by weight

Lucovyl MA 6035 80

Lucovyl MB 1000 20

Calcium stearate 0.5

Stabilizing DHP or G! 0.3

Stability in ventilated oven at 185 ° C.

Ingredients Lucovyl MA 6035 Lucovyl MB 1000 Calcium stearate DHP or G stabilizer,

Stability in ventilated oven at 185 ° C.

Parts by weight 80 20 0.5 0.3

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

14

Gl stabilizer

1

1

2

3

6

10

12.5

16

L. 28504

1

1

2

3

4

6

9

13

L. 28507

1

1

2

4

5

9

10

-

L. 28597

1

1

2

3

5

8

11

-

^ \ Time (min)

0

2

4

6

8

10

12

14

Stabilizing

Gj stabilizer

1

1

2

6

11.5

16

18

burnt

L. 28541

1

1

2

5

10

12

13

16

Example 25:

Comparison of DHP with stabilizer G,

Rigid vinyl copolymer formula, vinyl chloride / vinyl acetate copolymer.

Example 23:

Comparison of DHP with Gt stabilizer Rigid vinyl copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients Parts by weight

Lucovyl MA 6035 80

Lucovyl MB 1000 20

Calcium stearate 0.5

DHP or G stabilizer, 0.1

Stability in ventilated oven at 185 C.

Ingredients

Lucovyl MA 6035 Lucovyl MB 1000 Stabilizing calcium stearate

Stability in ventilated oven at 185 ° C.

Parts by weight

80 20 0.5 0.1

Time (min)

0

2

4

6

8

10

12

Stabilizing

Stabilizer G,

1

1

2

6

13

16

18

L. 28541

1

1

2

4

12

13

17

^^ Ternps (min)

0

2

4

6

8

10

12

14

Stabilizing

Stabilizer G,

1

1

6

7

11

12

14

16

Example 26:

Comparison of DHP to 2-phenyl indole

Rigid vinyl copolymer formula, vinyl chloride / vinyl acetate copolymer.

Ingredients Lucovyl MA 6035

Parts by weight 80

641780

18

Ingredients Parts by weight

Lucovyl MB 1000 20

Calcium stearate 0.5

Stabilizer 0.3

Stability in ventilated oven at 185 ° C.

^ \ Stabilizing time (min)

0

2

4

6

8

10

12

14

2-phenyl indole

1

1

2

3

8

12

14

17

L.28504

1

1

2

3

5.5

8

12

15

L. 28507

1

1

2

3

10

11

16

17.5

Example 29:

Comparison of DHP to 2-phenol indole

Rigid vinyl copolymer formula,

vinyl chloride / vinylidene chloride copolymer.

Ingredients Parts by weight

Solvic 223 PVC resin 90 IXAN SGA / 1 copolymer 10 BTA III reinforcing agent 8 Epoxidized soybean oil 4

0.2 calcium stearate

Zinc stearate 0.1

Lubricant 4,146 1.2

Lubricant 6164 0.4 Stabilizer x

Stability in ventilated oven at 210 ° C.

Example 27:

Comparison of DHP to 2-phenol indole

Rigid vinyl copolymer formula,

vinyl chloride / vinyl acetate copolymer.

Ingredients Parts by weight

Lucovyl MA 6035 80

Lucovyl MB 1000 20

Calcium stearate 0.5

Stabilizer 0.1 Stability in a ventilated oven at 185 ° C.

25

30

^^ \ Time (min)

0

2

4

6

8

10

12

14

Stabilizing

2-phenyl indole

1

1

2

3.5

10.5

13

16

18

L. 28504

1

1

2

3

7

11

13

17

^^ \ Time (min) Stabilizing

Quantity x of stabilizer (parts)

0

3

6

9

12

2-phenyl indole

0.3

1

1

4

10

15

L. 28597

0.3

1

1

2

4

12.5

L.28601

0.3

1

1

2

5

14

L.28541

0.3

1

1

2

4

8

L.28504

0.3

1

1

1.5

3.5

5

L. 28507

0.3

1

1

2

5

8.5

L.28507

0.7

1

1

2

5

7

L.28504

0.15

1

1

1.5

3.5

5.5

Example 28:

Comparison of DHP to 2-phenyl indole

Rigid vinyl copolymer formula,

vinyl chloride / vinylidene chloride copolymer.

Ingredients Parts by weight

Solvic 223 90 PVC resin

IXAN SGA / 1 copolymer 10 BTA III reinforcing agent 8 Epoxidized soybean oil 4

0.2 calcium stearate

Zinc stearate 0.1

Lubricant 4,146 1.2

Lubricant 6,164 0.4

Stabilizer 0.3

Stability in ventilated oven at 210 ° C.

^ "\ Stabilizing time (min)

0

3

6

9

12

15

2-phenyl indole

2

2

5

8.5

14

16

L.28504

1.5

1.5

2

3

10

-

L.28507

1.5

1.5

3

4

12.5

15

The results recorded in the table above show that:

- the dihydropyridines of formula I can be effective

45 as heat stabilizers for vinyl copolymers with a lower concentration in the formula than 2-phenyl indole,

A concentration of 0.15 per dihydropyridine of formula I and of L. 28504 in particular leads to a better result than 0.3 per of 2-phenyl indole,

n / a - the use of certain dihydropyridines of formula I instead of 2-phenyl indole may present an indisputable economic interest,

- increasing the amount of a dihydropyridine of formula I such as L. 28507 in the formula improves the duration of

55 stabilization, but has practically no influence on the coloration of the copolymer during the first 10 minutes of heating.

2.6 Study of antioxidant power

This study was carried out in two stages:

- it has been shown that the dihydropyridines according to the invention have antioxidant properties greater than those of known antioxidants such as hydroquinone, 4-methoxyphenol and ditert.-2,6-butyl-4-methylphenol,

65 - the antioxidant power of the dihydropyridines according to the invention has been shown directly on a vinyl resin, by comparison with an antioxidant very widely used in this field, di-tert.-butyl-2,6-methyl-4-phenol.

19

641,780

2.6.1 Polarographic study of the oxidation potential

Example 30:

a) Electrode operating conditions

- for reference: with calomel containing as a joining liquid a saturated solution of anhydrous lithium perchlorate,

- working: glassy carbon rotating electrode (2500 rpm),

- counter electrode: platinum.

Chemical products

- Acetonitrile having a water content <0.1% and not showing polarographic waves between —2.5 and +2.5 V.

- Anhydrous lithium perchlorate with a water content <1%.

Reagent

0.1 M solution of lithium perchlorate in acetonitrile, treated and stored on a 4 Å molecular sieve.

Polarographic conditions

- Voltage: 10 mV.

- Initial potential: 0 V.

- Exploration range: 0 to 2 V.

- Exploration speed: 10mV / s.

- Sensitivity: 1.25 to 50 nA -

average concentration 0.3 • 10 "3 mol / 1.

Caution: Between each measurement, the glassy carbon electrode and the platinum electrode are carefully cleaned with Joseph paper.

The following results were obtained:

Products

Compound L. 28504 Compound L. 28501 Ditert.-butyl-2,6-methyl-4 phenol Tert.-butyl-2-methoxy-4 phenol Hydroquinone Methoxy-4 phenol

Oxidation potential 0.74 + 0.01 0.73 + 0.01 1.11 + 0.02 0.81 + 0.01 0.83 + 0.01 0.89 + 0.01

Polarographic conditions

- Square voltage superimposed with constant pulses of +10 mV.

- Initial potential: 500 mV.

- Scanning amplitude: 1000 mV in the anodic direction.

- Oxidation at the glassy carbon electrode (speed of rotation: 2000 rpm).

- Temperature: 35 ° C.

The determinations were carried out at a concentration of 0.5 mmol / 1 for BHT, a low molecular weight dihydropyridine derivative (L. 28504: R = methyl) and three heavy dihydropyridine derivatives (L. 28507: R = dodecyl ; L. 28602: R = oleyl; L. 28590: R = myristyle).

b) Results

The following table indicates the values obtained in millivolts, for the oxidation potential and the nature of the radical R of the corresponding formula I.

Products tested

Oxidation potential (mV)

BHT

+ 1163

L.28504

+ 850

L. 28507

+ 783

L.28602

+ 808

L.28590

+ 732

Examination of these results leads to the following conclusions:

- the dihydropyridines I have a much lower oxidation potential than that of BHT and, consequently, more powerful antioxidant properties,

- the heavy dihydropyridines I (L. 28507, L. 28590, L. 28602) have a lower oxidation potential than that of the lightest dihydropyridine I (R = - CH3; L. 28504) and, consequently, manifest superior antioxidant properties.

2.6.2 Study of the antioxidant power on a vinyl resin

The study was carried out with the resin below containing, as antioxidant, the compound L. 28504, or BHT.

The values found show that the dihydropyridines according to the invention are more reducing than the reference antioxidants.

Example 31: 45

a) Electrode operating conditions

- platinum counter electrode and calomel electrode with filling with a saturated aqueous solution of lithium chloride. 50

Reagent

The measurements were carried out in the following solvent:

- 90 parts of 0.1 M solution of lithium perchlorate in methanol, 55

- 10 parts of 0.1 M solution of perchloric acid in acetic acid.

Ingredients

Polyvinyl chloride resin Shockproof agent Acrylic resin Epoxidized soybean oil SL 2016

Calcium and zinc stearates Hydrogenated castor oil Polyethylene wax Antioxidant

Parts by weight 100 10 0.5 3 0.1 0.2 1.5 0.3 0.05 to 1

The stability bands were examined:

in a conventional oven at 185 ° C every 10 min for 80 min,

in a Metastat oven at 210 ° C for 1 h.

The coloration was calculated according to the Gardner scale.

The results below were obtained.

a) Oven at 185 ° C

Concentrations

Antioxidant

Time (min)

0

10

20

30

40

50

60

70

80

0.05

BHT L. 28504

> 1 1

1 + 1

2 ~ 1 +

5+ 3 +

> 6 4 ~

1

6+

7 7

8 8

B B

641780

20

Concentrations

Antioxidant

Time (min)

0

10

20

30

40

50

60

70

80

0.1

BHT L. 28504

> 1 1

1 + 1

2 "1 +

> 5 <2

> 6 3+

7

5+

7 7

8 7

B B

0.2

BHT L.28504

> 1 1

1 + 1

2+ 1

5 "1 +

> 6 2

7 3

7 5

8

> 6

B B

0.3

BHT L.28504

<1 + 1

1 + 1

> 2 1

> 6 1

7 2

8

> 2

8 8

8 + 8

B B

0.4

BHT L. 28504

<1 + 1

> 1 + 1

3 1

> 6 1

8 "1 +

9> 2+

9 4

9 8

B B

0.5

BHT L. 28504

<1 + 1

> 1 + 1

3 1

> 6> 1

> 7 1 +

8 "

> 2+

1

OO

8 8

B B

1

BHT L.28504

1-1

2 "1

> 3 1

8 1

8

1+

8 4

9 8

9 B

B

The sign B means burned while the index + means that the coloring is located halfway between the lower unit and the half

upper unit. Likewise, the index - signifies that the coloration can be concluded from the above results that the compound L.

located between the lower half unit and the upper unit. Finally, we are very clearly superior to the reference compound, during consider for example that> 2 means between 2 and 2+. 30 50 min, for all antioxidant concentrations.

b) Metrastat oven at 210 ° C

Time (min)

y-1. . •

i, <j,

concentrations

Antioxidant

0 to 10

10 to 20

20 to 25

25 to 30

30 to 35

35 to 40

0.05

BTH

2 ~

2

3 "

4+

10

> 10,

B to 38

L. 28504

1

1

1

1

5 "

> 10,

Bà40

0.1

BHT

2 "

2

3 "

4+

11

> 11,

B to 39

L.28504

1

1

1

1

5 "

<10,

B to 38

0.2

BHT

2 "

2

3 "

4+

11

> 11,

B to 39

L. 28504

1

1

1

1

5 "

<9,

B to 39

0.3

BHT

<1

2 "

3 ~

3

9

<10,

B to 39

L.28504

1

1

1

1

3+

<6,

B to 39

0.4

BHT

2_

2

3

3+

10

> 10,

B to 38

L.28504

1

1

1

1

4 ~

6 ",

B to 38

0.5

BHT

2 ~

2

3

3 +

10+

> 10+,

B to 38

L. 28504

1

1

1

1

3+

6 ",

B to 38

21

641780

Concentrations

Antioxidant

Time (min)

Where

10 to 20

20 to 25

25 to 30

30 to 35

35 to 40

1

BHT

2 ~

2

3 "

5

11

> 11,

B to 38

L.28504

1

1

1

1

2+

> 2+,

B to 38

The results also show the clear superiority of the compound Example 32:

L. 28504 on the reference compound.

It should also be noted that, from time zero, the plates containing BHT show a pink coloration, which constitutes another disadvantage of BHT.

2.7 Study of the lubricating power

The lubricity was judged by the bonding time which was determined on a calendering mixer equipped with heating rollers and compared with that of a reference stabilizer.

The temperature of the cylinders was 165-170 ° C and the reference stabilizer stabilizer G ,.

Ingredients Parts by weight

Solvic 547 SA 80

Lacqvyl S-071-S Irgawax 280 Stabilizing calcium stearate

20 0.1 0.5

0.3 to 0.8

No. of tests

Amount of stabilizer (per)

Stabilizer n.

1

2

3

4

5

6

7

L. 28504 L. 28507 L.28596 Stabilizer G!

0.3

0.3

0.7

0.3

0.8

0.3

0.7

Bonding time

12 '

12'45 "

1730 "

12'30 "

17'20 "

12 '

16'20 "

These results show that:

at equal concentration (0.3 per), the dihydropyridines of formula I and the stabilizer Gx have a very similar bonding time with an advantage for dihydropyridines of high molecular mass L. 28507 and L. 28596,

at equimolecular concentration (0.3 per L. 28504.0.7 per L. 28507.0.8 per L. 28596), the lubricity of L. 28507 and L. 28596 is significantly higher than that of L. 28504,

whatever the concentration, the lubricating power of the dihydropyridines of formula I is at least comparable to that of the stabilizer G,; it is higher for L. 28507 and L. 28596; this comparison shows that dihydropyridines can be substituted for aminocrotonates for the manufacture of discs for example.

Example 33:

The cylinder temperature was 180-190 ° C and the reference stabilizer 2-phenyl indole.

Ingredients Parts by weight

Solvic 223 100 PVC resin

Shockproof (BTA III) 8

Epoxidized soybean oil 2

Stabilizer x

Working conditions on the calendering mixer

Front cylinder: temperature 190'C.

Rear cylinder: temperature 180 'C.

Products

R

x (per)

Bonding time

(min)

(s)

L.28504

-ch3

0.5

12

17

L. 28501

-c2h5

0.5

11

25

L. 28506

- ch (ch3) 2

0.5

8

0

0.527

8

30

0.555

9

0

L.28502

- (ch2) 7 —ch3

0.5

12

19

0.665

13

25

0.83

15

25

L. 28591

- (ch2) 9-ch3

0.5

13

29

0.72

16

10

0.94

18

30

L.28507

- (CH2), J —ch3

0.5

14

36

0.775

19

10

1.05

22

45

It appears from these results that, in the series of dihydropyridine molecules I, those in which the radical R contains from 9 to 22 carbon atoms lead to a bonding time markedly greater than that observed for the lower homologs, when they are used in quantities equimolecular or in equal amounts. This increase in bonding time represents 15 to 50% of the average bonding time of the group of dihydropyridines whose radical R varies between 1 and 8 carbon atoms.

In particular, 2,6-dimethyl-3,5-dicarbododecyloxy-1,4-dihydro-1,4-pyridine shows, in all the formulas examined, a significant improvement in the bonding time.

641780

22

These properties should be emphasized, because they can lower the cost of stabilization by reducing the rate of lubricants or improving the passage of the PVC compound on the machines carrying out the extrusion and blowing.

The fact of increasing the dimension of the radical R in formula I therefore makes it possible to bring to this general structure three interesting properties which the lower homologs (R <C8) of the series do not possess, which limits the use of these lower counterparts and even excludes it in the food sector (migration). The increase in molecular weight does not however modify the photostabilizing and thermostabilizing properties of these molecules compared to the lower homologs.

R

Claims (4)

641780 2. Process for the preparation of a compound of formula (I) according to claim 1, characterized in that an acetoacetate of formula CH3 - CO — CH2 — COOR is reacted in which R has the meaning given to claim 1, with formalin and ammonia. 2 CLAIMS 1. Compound of formula o o It ii RO — C * C — OR (i) h, C / ^ N / X: H-, 3. Method according to claim 2, characterized in that formalin and ammonia are formed in situ following the use, in the reaction mixture, of an ammonium salt and hexamethylene tetramine. 3 i 3 H in which R represents an alkyl, alkenyl or alki-nyl group, linear or branched in Cg E C22Ï a cyclohexyl radical or a phenyl radical optionally substituted by a halogen atom or by a methyl or methoxy radical. 4. Use of a compound of formula (I) according to claim 1, for stabilizing the vinyl resins against light and / or heat.