STERICALLY HINDERED AMINE STABILIZER MIXTURES

Abstract

The present invention relates to mixtures of sterically hindered amines of the formulae (1) and (2)

##STR00001##

wherein
at least one of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 is C.sub.1-C.sub.18 alkyloxy or C.sub.5-C.sub.7 cycloalkyloxy and the remaining of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are hydrogen, hydroxy, C.sub.1-C.sub.18 alkyloxy or C.sub.5-C.sub.7 cycloalkyloxy, and
at least one of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 is a group of formula —CH.sub.2—CH═CH—R and the remaining of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are hydrogen or a group of formula —CH.sub.2—CH═CH—R, and
the other substituents are as defined according to the present invention,
methods for stabilization of an organic material, and
a process for the preparation of compounds of formula (1′).

Claims

1. An additive mixture comprising a compound of formula (1) ##STR00012## and a compound of formula (2) ##STR00013## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R′.sub.1, R′.sub.2, R′.sub.3 and R′.sub.4 are independently from each other hydrogen or C.sub.1-C.sub.18 alkyl, X.sub.1 and X′.sub.1 are independently from each other C.sub.2-C.sub.12 alkylene or C.sub.3-C.sub.12 alkylene substituted by hydroxyl; at least one of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 is C.sub.1-C.sub.18 alkyloxy or C.sub.5-C.sub.7 cycloalkyloxy and the remaining of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are independently from each other hydrogen, hydroxy, C.sub.1-C.sub.18 alkyloxy or C.sub.5-C.sub.7 cycloalkyloxy, and at least one of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 is a group of formula —CH.sub.2—CH═CH—R and the remaining of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are independently from each other hydrogen or a group of formula —CH.sub.2—CH═CH—R, wherein R is hydrogen, C.sub.1-C.sub.18 alkyl or C.sub.5-C.sub.7 cycloalkyl.

2. An additive mixture according to claim 1, wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R′.sub.1, R′.sub.2, R′.sub.3 and R′.sub.4 are C.sub.1-C.sub.12 alkyl.

3. An additive mixture according to claim 1, wherein X.sub.1 and X′.sub.1 are C.sub.2-C.sub.8 alkylene.

4. An additive mixture according to claim 1, wherein one to five radicals of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are C.sub.1-C.sub.18 alkyloxy or C.sub.5-C.sub.7 cycloalkyloxy and the remaining of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are hydrogen or hydroxy.

5. An additive mixture according to claim 1, wherein Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 in the meaning as C.sub.1-C.sub.18 alkyloxy are a group of formula —O—CH.sub.2—CH.sub.2—CH.sub.2—R, wherein R is hydrogen or C.sub.1-C.sub.15 alkyl.

6. An additive mixture according to claim 1, wherein one to five radicals of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are a group of formula —CH.sub.2—CH═CH—R and the remaining of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are hydrogen.

7. An additive mixture according to claim 1, wherein R is hydrogen.

8. An additive mixture according to claim 1, wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R′.sub.1, R′.sub.2, R′.sub.3 and R′.sub.4 are C.sub.1-C.sub.12 alkyl, X.sub.1 and X′1 are C.sub.2-C.sub.8 alkylene, one to five radicals of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are C.sub.1-C.sub.18 alkyloxy or C.sub.5-C.sub.7 cycloalkyloxy and the remaining of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are hydrogen or hydroxy, one to five radicals of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are a group of formula —CH.sub.2—CH═CH—R and the remaining of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are hydrogen, and R is hydrogen.

9. An additive mixture according to claim 1, wherein the weight ratio of compound of formula (1) to compound of formula (2) is 5:95 to 95:5.

10. A composition comprising a) an organic material which is susceptible to oxidative, thermal or light-induced degradation; and b) an additive mixture as defined in claim 1.

11. A method for stabilization of an organic material susceptible to oxidative, thermal or light-induced degradation, comprising incorporating an additive mixture as defined in claim 1 in the organic material or applying an additive mixture as defined in claim 1 to the organic material.

12. A method for improving flame retardancy of an organic material, comprising incorporating an additive mixture as defined in claim 1 in the organic material or applying an additive mixture as defined in claim 1 to the organic material.

13. A method for stabilization of an organic material susceptible to oxidative, thermal or light-induced degradation, comprising incorporating a compound of formula (2) as defined in claim 1 in the organic material or applying a compound of formula (2) as defined in claim 1 to the organic material.

14. A process for the preparation of a compound of formula (1′) ##STR00014## comprising subjecting a compound of formula (2) ##STR00015## to an oxidation reaction, followed by a hydrogenation reaction, wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R′.sub.1, R′.sub.2, R′.sub.3 and R′.sub.4 are independently from each other hydrogen or C.sub.1-C.sub.18 alkyl, X.sub.1 and X′.sub.1 are independently from each other C.sub.2-C.sub.12 alkylene or C.sub.3-C.sub.12 alkylene substituted by hydroxyl; one to five radicals of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are a group of formula —O—CH.sub.2—CH.sub.2—CH.sub.2—R and the remaining of the radicals Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are hydrogen or hydroxy, one to five radicals of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are a group of formula —CH.sub.2—CH═CH—R and the remaining of the radicals Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are hydrogen, and R is hydrogen or C.sub.1-C.sub.15 alkyl.

Description

EXAMPLES

Synthesis and Preparation Examples

[0190] Example 1: Synthesis of compound of formula (1-A), wherein 70 mole-% of Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4, Z.sub.5 and Z.sub.6 are n-propyloxy and the remaining of these radicals are hydrogen or hydroxy. In the following this compound is referred to as compound (101).

[0191] a) Synthesis of compound of formula (2-A), wherein 80 mole-% of Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are an allyl group and the remaining of these radicals are hydrogen. In the following this compound is referred to as compound (201).

[0192] In a one liter autoclave equipped with a mechanical stirrer 0.94 mol of Na.sub.2CO.sub.3 and 0.14 mol of the compound of formula (301)

##STR00011##

dissolved in xylene to reach 45 weight-% concentration are added, then 0.79 mol of allyl bromide are added. The mixture is heated at 145° C. for 7 hours, cooled down to 60° C. and washed with 26.7 mol of water at 85° C. A second washing is performed with 0.05 mol of Na.sub.2CO.sub.3 dissolved in 11.1 mol of water. The organic phase is directly used in the following step without any further purification. Conversion: 80%.

[0193] b) Oxidation of compound of formula (201)

[0194] The reaction mixture as obtained according to the above step a) is diluted to 32 weight-% concentration with xylene and is placed in a glass reactor equipped with a mechanical stirrer, thermocouple and a dropping funnel. 1.13 mol of Na.sub.2CO.sub.3 are added. The suspension is cooled down to 0° C. and 0.86 mol of peracetic acid solution (35 weight-% in water) is slowly added over 3 hours. Afterwards, 16.7 mol of water are added and the mixture is warmed up and stirred at 75° C. for 1 hour. The organic phase is separated, washed with 0.07 mol of Na.sub.2CO.sub.3 and 5.56 mol of water. The organic phase is directly used in the following step without any further purification. Conversion: 93%

[0195] c) Final synthesis of compound (101)

[0196] From the reaction mixture as obtained according to the above step b) solvent is removed to get a final concentration between 45 and 60 weight-%. The solution is loaded in a one liter autoclave together with 0.14 mmol of Pd/C (5 weight-%) The overall mixture is heated at 70° C. under 30 bar hydrogen for 4 hours.

[0197] The solution is cooled to room temperature, filtered to remove the catalyst and dried under reduced pressure. A slightly pinkish solid is obtained. Conversion: 98%. Softening range: 110-150° C.

[0198] Example 2: Synthesis of compound of formula (2-A), wherein all of Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are an allyl group. In the following this compound is referred to as compound (202).

[0199] Synthesis is carried out according to Example 1 a), but using 1.29 mol of allyl bromide (instead of 0.79 mol of allyl bromide).

[0200] Compound (202) is isolated removing the solvent under reduced pressure to get a solid.

[0201] Example 3: Synthesis of compound of formula (2-A), wherein 50 mole-% of Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 are an allyl group and the remaining of these radicals are hydrogen. In the following this compound is referred to as compound (203).

[0202] Synthesis is carried out according to Example 1 a), but adjusting the amount of allyl bromide used accordingly.

[0203] Example 4: Preparation of mixtures

[0204] Compounds (101), (201), (202) and (203) are isolated as given in Example 2 above. The mixtures given in the following Application Example 1, Table 1, are prepared by homogenously mixing the solids of the corresponding compounds in the indicated weight ratio.

[0205] Alternatively, it is also possible to mix directly the reaction mixtures of the compounds to be mixed, and then to remove the solvent under reduced pressure to get solid mixtures.

Application Examples

Application Example 1: Stabilization of LDPE (Low Density Polyethylene) Multi-Layer Films

[0206] Masterbatch formulations are prepared, containing 10% by weight in total of the light stabilizer(s) indicated in Table 1 below, 0.4% by weight of tris{2,4-di-tert-butylphenyl} phosphite and 0.1% by weight of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate as process stabilizers, and the rest of polyethylene powder (Polimeri Europa Riblene® FC 30, characterized by a density of 0.922 g/cm.sup.3 and a melt flow index (190° C./2.16 Kg) of 0.27 g/10 min). The masterbatch formulations are mixed in a turbo-mixer. Each masterbatch formulation is extruded at a maximum temperature of 200° C. in a lab-scale OMC twin-screw extruder (Ø 19 mm, L/D=25). 360 g of the granules so obtained for each masterbatch formulation are mixed with 30 g of a polyethylene masterbatch containing 0.4% by weight of tris{2,4-di-tert-butylphenyl} phosphite and 0.1% by weight of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate as process stabilizers and with 5610 g of the above indicated virgin polyethylene in pellets, in a Rhonrad® slow mixer for 10 minutes, resulting in the final formulation that contains 0.6% in total of the light stabilizer(s) indicated in Table 1 below. Then, each final formulation is blown in a lab-scale Collin® 5-layer blow-extruder (Ø 20-25-30 mm, L/D 25), at a maximum temperature of 210° C., to give a 5-layer film of overall 150 μm thickness (45-5-50-5-45 μm), having the same formulation in all layers. The following formulations are prepared:

TABLE-US-00001 TABLE 1 Formulation Light stabilizer(s) 1C Comparative 0.6% by weight of compound (301) Formulation 2 Inventive 0.6% by weight of compound (201) Formulation 3C Comparative 0.3% by weight of compound (301) Formulation 0.3% by weight of compound (101) 4 Inventive 0.3% by weight of compound (203) Formulation 0.3% by weight of compound (101) 5 Inventive 0.3% by weight of compound (201) Formulation 0.3% by weight of compound (101) 6 Inventive 0.3% by weight of compound (202) Formulation 0.3% by weight of compound (101)

Application Example 2

[0207] Film specimens for each formulation are exposed in a Q-Panel QUV/se piece of equipment (QUV, as per ASTM G154, 1.55 W/m2 at 340 nm, cycle 6) for accelerated light weathering. Such specimens are taken at defined intervals and evaluated for embrittlement. The longer the time to embrittlement the better the stabilizing effect from the sterically hindered stabilizers in the different formulations. The results are reported in Table 2 below. It can be observed that formulation 2, based on compound (201) object of the present invention, is better than formulation 1C and that formulations 4, 5 and 6, based on mixtures with compound (201) or its homologues, are better than formulation 3C.

TABLE-US-00002 TABLE 2 Time to Formulation embrittlement (hours) 1C 4991 2 7034 3C 7034 4 7528 5 8490 6 8490

[0208] Higher times to embrittlement are desired.

Application Example 3

[0209] This test is aimed at combining light irradiation and use of agrochemicals known to have a detrimental effect on the light stability performance of the light stabilizers contained in them. To achieve such a purpose, an agrochemical treatment is carried out on the prepared films before artificial weathering. Specimens of the films for each formulation are mounted on a small experimental greenhouse (geographical coordinates: Lat. 44° 25′40″N Long. 11° 16′39″E), inside of which a treatment with metam sodium, a sulfur-based fumigant used in agricultural practice, is carried out. After the treatment the small greenhouse is covered with a single piece of opaque film to block the direct exposure of the sample to sunlight, in order to minimize in turn the effects of solar irradiation and hence the possible differences on samples exposed in subsequent test series. The experimental conditions are closely monitored, so as to obtain the desired level of contamination from sulfur in the film samples, measured by Inductively Coupled Plasma.

[0210] After the agrochemical treatment, the film specimens for each formulation are exposed in an Atlas Weather-O-Meter (WOM, as per ASTM G155, 0.35 W/m2 at 340 nm, dry cycle), for accelerated light weathering. Specimens of the required formulations are taken at defined intervals of time after exposure and undergo carbonyl increment evaluation. The carbonyl increment is measured by means of a Perkin-Elmer® Spectrum 100 FT-IR spectrophotometer, as a measure of the oxidation degree of the polymer, so low levels of carbonyl are desired. The results are reported in table 3. It can be observed that formulation 2, based on compound (201) object of the present invention, is better than formulation 1C and that formulations 4, 5 and 6, based on mixtures with compound (201) or its homologues, are better than formulation 3C.

TABLE-US-00003 TABLE 3 Carbonyl increment after Formulation 2992 WOM exposure 1C 0.076 2 0.041 3C 0.067 4 0.051 5 0.045 6 0.036

[0211] Low carbonyl increment is desired.

Application Example 4

[0212] An agrochemical treatment is carried out, as described in Application Example 3. After the agrochemical treatment, the film specimens for each formulation are exposed in an Atlas Weather-O-Meter (WOM, as per ASTM G155, 0.35 W/m2 at 340 nm, dry cycle), for accelerated light weathering. Specimens of the required formulations are taken at defined intervals of time after exposure and undergo the evaluation of the mechanical properties. The residual elongation at break is measured, by means of a Zwick® Z1.0 constant velocity tensiometer (as per modified ISO 527), in order to evaluate the decay of the mechanical properties of the plastic film, as a consequence of the polymer degradation after its oxidation.

[0213] The results are reported in Table 4.

TABLE-US-00004 TABLE 4 Time in hours to reach 50% of the Formulation initial elongation to break 1C 1698 2 2492 3C 7058 5 7564 6 8183

[0214] High values are desired.

Application Example 5

[0215] Like Application Example 3, this test is aimed at combining light irradiation and use of agrochemicals. In this test too, an agrochemical treatment is carried out on the prepared films before artificial weathering. Specimens of the films for each formulation are mounted outdoor in an experimental cabinet (geographical coordinates: Lat. 44° 25′40″N Long. 11° 16′39″E), inside of which some burners of the type used in common agricultural practice are placed to allow sublimation of elemental sulfur, a widely used fungicide. The so-called “sulfur burning” is carried out so as to burn a specific weighted amount of sulfur. The amount of burnt sulfur is regulated and the weathering conditions closely monitored, so as to obtain the desired level of contamination from sulfur in the film samples, measured by Inductively Coupled Plasma.

[0216] After the agrochemical treatment, the film specimens for each formulation are exposed in an Atlas Weather-O-Meter (WOM, as per ASTM G155, 0.35 W/m2 at 340 nm, dry cycle), for accelerated light weathering. Specimens of the required formulations are taken at defined intervals of time after exposure and undergo carbonyl increment evaluation The carbonyl increment is measured by means of a Perkin-Elmer® Spectrum 100 FT-IR spectrophotometer, as a measure of the oxidation degree of the polymer. The results are reported in Table 4 below. It can be observed that formulation 5, based on mixture between compound (201) and compound (101), object of the present invention, is better than formulation 3C, showing a better light stabilization, when in presence of agrochemical treatment.

TABLE-US-00005 TABLE 5 Carbonyl increment after Formulation 2502 WOM exposure 3C 0.143 5 0.094

[0217] Low carbonyl increment is desired.

Application Example 6

[0218] An agrochemical treatment is carried out, as described in Application Example 5. After the agrochemical treatment, the film specimens for each formulation are exposed in an Atlas Weather-O-Meter (WOM, as per ASTM G155, 0.35 W/m2 at 340 nm, dry cycle), for accelerated light weathering. Specimens of the required formulations are taken at defined intervals of time after exposure and undergo the evaluation of the mechanical properties, as described in Application Example 4. The results are reported in Table 6 below.

TABLE-US-00006 TABLE 6 Time in hours to reach 50% of the Formulation initial elongation to break 3C 2628 5 3098

[0219] High values are desired.