CS257380B1 - Ethylene-vinylacetate copolymere containing 7,15-diaxadispiro(5,1,5,3)hexadecyle groups - Google Patents

Description

The invention relates to an ethylene-vinyl acetate copolymer containing 7,15-diazadispiro [5,1,5,3] hexadecyl groups.

Sterically shielded amines are currently considered to be the most effective light stabilizers of polymers [F. Gugumus, Kunstoffe 1984, 74 (10), 620, F. E. Karrer, Macromol. Chem., 181, 595 (1980)]. They are various derivatives of 2,2,6,6-tetramethyl- or 1,2,2,6,6-pentamethylpiperidine, 2,2,6,6-tetraalkylpiperazine, 7,15-diazadispiro15,1,5,3) hexadecane 2,2,5,5-tetraalkylpyrrolidine.

The sterically shielded amines inhibit the degradation reactions of polymers that interact with oxygen and sunlight with high efficiency. A disadvantage of the low molecular weight derivatives of sterically shielded amines is their volatility and extractability from utility polymers. The preparation of the copolymer of the present invention eliminates volatility loss of the stabilizer and reduces its extractability, especially in polyolefins. The compound based on the chemically modified ethylene-vinyl acetate copolymer of the present invention does not hitherto be described in the literature.

The present invention provides an ethylene-vinyl acetate copolymer containing 7,15-diazadispiro [5,1,5,3] hexadecyl groups of formula I

p - C., C'L xí Z. t «—.-- 1 C 11 -CU 1 £ 0 c // οΗ _Λ 'Λo I oo what - m x _ ^CH S (N-p) x R-CH-CH-R ² about

clay) where

R ¹ is H or -CH 2 _; R ² is

m = 4 to 60, n = 2 to 4, p = 1 to 3 and x has a value in the range of 40 to 2. The invention further provides a process for preparing a copolymer of formula I, characterized in that the ethylene-vinyl acetate copolymer of formula II

CH _? - CHO í Z mx

- CH-CH. , · C

O i

0 = 0 CO hx (ti) where m

to 60, n = 2 to 4, and x has a value of from 40 to 2 is treated with an alkyl ester of 3- [15,15- [7,15-diazadispiro (5,1S, 5-hexadecyl)] propanoic acid III

CW - CW - COOR ³

I t her o

'N

H (H1) where

R ¹ is hydrogen or methyl, and R ³ is methyl or ethyl, in dry toluene or xylene at reflux temperature under a nitrogen atmosphere, catalysing lithium amide or a mixture of lithium amide and sodium amide.

EXAMPLE 1 g of a granular ethylene-vinyl acetate copolymer (II) (Mn-17,800) having a content of 23.5% by weight. (0.041 mol) of vinyl acetate is dissolved in 120 ml of xylene (a mixture of xylenes after distillation in the presence of sodium) after drying under a vacuum of 0.1-0.3 kPa (at 50 ° C for 4 h). After dissolution at 100 ° C with stirring and flow of dried nitrogen, 0.6 g (0.026 mol) of lithium amide suspended in powder form in 10 ml of dried xylene is added. 40 min. 12.5 g (0.039 mol) of 2-methyl-3- (15- [7,15-diaazadispiro (5,1,5,3) hexadecyl]) propanoic acid methyl ester (III) is then added under stirring.

The temperature was raised to 125 ° C and after 20 min. 2.5 g (0.008 mol) of methyl ester III are added and the reaction is continued in a polymer-analogue reaction with stirring for 110 min under inert atmosphere. at reflux temperature. The solution was cooled and added successively to 500 ml of 90% aqueous ethanol with stirring. The precipitated copolymer is separated by filtration and then extracted in 200 ml of 90% aqueous ethanol for 10 h. After isolation, the yellowish product is air dried at 20-25 ° C and then dried in powder form in a vacuum oven at 45 ° C under 0.2-0.4 kPa. The dried product having a number average molecular weight of 19,200 (Mn determination by VPO method), contains 4.2% by weight. nitrogen.

Example 2

An analogous procedure to that described in Example 1 was followed except that 15 g of ethylene vinyl acetate copolymer (Mn-27 400) with a vinyl acetate content of 18% by weight was used for the polymer analog reaction. (0.031 mol), 12.9 g (0.04 mol) of 3- (15- [7,15-diazadispiro (5,1,5,3) hexadecyl] propanoic acid ethyl ester, and a mixed system of 0.4 g ( 0.0174 mol) of lithium amide and 0.3 g (0.0065 mol) of sodium amide are suspended in powder form in 15 ml of absolute o-xylene to give a yellowish product with a nitrogen content of 3.92% mass and Mn 29 500.

Example 3

100 parts by weight of unstabilized powdered polypropylene are mixed with 0.1 wt. parts by weight of 2,6-di-tert-butyl-4-methylphenol, 0.5 wt. parts by weight of the copolymer prepared according to Example 1 and 0.15 wt. The mixture is homogenized in a melt in a mixing chamber of a Brabender plastograph under a nitrogen atmosphere at 190 ° C for 5 min. A sheet of 0.15 mm thickness is pressed from the mixture obtained at a pressure of 50 bar and a temperature of 220 degrees Celsius. The samples prepared from this film are then irradiated with a 125 W mercury lamp at 7 cm from the source. Sample degradation is monitored by developing the carbonyl band in infrared spectra. The time to reach a carbonyl index of 0.2 under these conditions for a polypropylene film not containing a light stabilizer is reached in 140 hours, whereas for a stabilized film this value is reached in 1,660 hours.

Claims (2)

Wherein R 1 is hydrogen or methyl and R 3 is methyl or ethyl, in toluene or xylene dried at low flow temperature under a nitrogen atmosphere under lithium catalysis or lithium amide / sodium amide mixtures. Example 1 15 g of granular ethylene-vinylacetate copolymer (II) (Mn - 17,800) containing 23.5 wt. 0.3 kPa (at 50 ° C for 4 h) dissolved in 120 ml of xylene (xylene mixture after distillation in the presence of sodium) 0.6 g (0.026) was added at 100 ° C with stirring and drying of nitrogen. 12.5 g (0.039 mol) of methyl 2-methyl-3- (15-7, 7 mol) are added in 10 ml of dried oxylene over 10 min. 15-diastispiro (5,1,5,3-hexadecyl) -propanoic (III) The temperature is raised to 125 ° C and 2.5 g (0.008 mol) of methyl ester IIIa are added in an inert atmosphere after polymerization for 20 min. with stirring for 110 min at low temperature, the solution is cooled and gradually added to 500 ml of 90% aqueous ethanol with stirring. the polymer is separated by filtration and then extracted in 200 ml of 90% non-aqueous ethanol for 10 h. After isolation, the yellowish product is air-dried at 20-25 ° C and then the powder form is dried in a vacuum drier. 45 ° Cza pressure 0.2-0.4 kPa. The dried product with a number average molecular weight of 19,200 (determination of Mn by VPO method) contained 4.2% by weight. nitrogen. EXAMPLE 2 An analogous procedure to that used in Example 1 was followed except that 15 g of an ethylene vinyl acetate copolymer (Mn - 27,400) with a vinyl acetate content of 18% by weight (0.031 mol) were used for the polymer-analogous reaction. 9 g (0.04 mole) of ethyl 3- (15- [7,15-diazadispiro (5,1,5,3) -hexadecyl] propanoic acid) and 0.4 g (0.0174 mole) mixed system catalyst and lithium amide and 0.3 g (0.0065 mol) of amide sodium, which are suspended in powdered form in 15 ml of absolute o-xylene to give a yellowish product with a nitrogen content of 3.92. EXAMPLE 3 100 parts by weight of unstabilized polypropylene powder are mixed with 0.1 parts by weight of 2,6-di-tert-butyl-4-methylphenol, 0.5 parts by weight of copolymer. of the calcium stearate and the mixture is homogenized in the melt in a Brabender plasmasgraph mixing chamber under nitrogen atmosphere. The temperature of the mixture obtained was 190 ° C for 5 minutes, and 0.15 millimeters thick film was pressed from the obtained mixture at a pressure of 5 MPa and a temperature of 220 degrees Celsius. Samples prepared from this foil are then irradiated with a 125 W mercury discharge lamp at a distance of 7 cm from the source. The degradation of the sample is monitored by developing the carbonyl band in the infrared spectra. The carbonyl index time of 0.2 under these conditions for a polypropylene film not containing a light stabilizer is reached after 140 hours, while the stabilized film reaches a value of 1560 hours. SUBJECT MATTER An ethylene-vinylacetate copolymer comprising a 7,15-diazadiaziro [5,1,5,3] hexadecyl group of formula I - CH 2 - CH 2 -. iL CH-CW. I-O-c-o-mx CHd (n-p) x -CAt-CH 1 - f 2 O 10 10 1 / r-CH-C / y 2 R 2 O (R 237380 where R 1 is hydrogen or methyl R 2 is H m = 4 to 60, n = 2 to 4, p = 1 to 3 and x has a value in the range of 40 to 2. 2. A process for the preparation of compound (I) according to claim 1, characterized in that the ethylene-vinyl acetate copolymer of formula (II) r- - C / 1 CH 2 CHCH 2 O mx OC CH 2 (m) wherein m - 4 to 60, n = 2 to 4, x has a value in the range of 40 to 2, provide the alkyl esters of 3- {15- [7,15-diazadispiro (5,1,5,3-hexadecyl] -propane of formula III) where R 1 is hydrogen or methyl and R 3 is methyl or ethyl, in toluene or xylene at low flow temperature and under nitrogen atmosphere, lithium amide or lithium amide / amide mixtures of catalysis. Severografia, n. P. Plant 7, Most Price 2,40 Kcs