CS229080B1 - Polyamides of the type of sterically hindered piperazinediones on the basis of alpha,alpha'-di-substituted dicarboxylic aliphatic acids - Google Patents

Description

The invention relates to polyamides of the sterically hindered piperazinediones type based on α, α'-disubstituted dicarboxylic aliphatic acids comprising in their chain a structural unit of the general formula

n is in the range of 2 to 10 and the method of preparation thereof.

The method for the preparation of sterically hindered piperazinediones-type polyamides based on σ'-disubstituted dicarboxylic aliphatic acids is based on ammonolysis of a compound of formula

wherein R is an alkyl of 1 to 2 carbon atoms, m has a value of 0 to 6, aliphatic diamines having a carbon number of 2 to 6, such as ethylenediamine, hexamethylenediamine, at a temperature ranging from 100 to 150 ° C in a dry hydrocarbon solvent (toluene, xylene, nitrobenzene) in the presence of a basic catalyst such as lithium amide, tetrapropyltitanate.

Sterically hindered amines are high-efficiency light stabilizers of many types of polymers. However, the use of low molecular weight substances of this type has some limitations. Their main drawbacks are: high drowsiness, considerable migration ability, long extractability and, last but not least, good absorbability into the cellular spaces of living organisms.

The first three undesirable properties are the cause of their gradual loss from the utility polymer, with the concomitant loss of protective effect, first in its heat treatment, then in longer storage and ultimately in its chemical cleaning or laundering, the tight cell cell penetration of living organisms over considerable toxicity of low molecular weight hindered amines exclude them from application in the stabilization of polymeric materials in the food industry, possibly in the medical field.

The reduction or elimination of these disadvantageous properties presupposes the use of light-molecular, oligomeric or polymeric light stabilizers with satisfactory tolerance, or the attachment of stabilizing structures to the utility polymer chain.

The polymeric light stabilizer of the piperazine type belonging to the group of sterically hindered amines object of the invention can serve to suppress or eliminate said drawbacks of the low-molecular-weight substances of said type.

EXAMPLE

A mixture of 2.0967 g (0.003 mol) of 2,5-bis- (7,15-diazadispiro [5,1,5,3] hexadecane-14,16-dione-15-yl) hexanedioic acid diethyl ester and 0.34853 g (0.003 mol) of hexamethylenediamine in 15 ml of dry xylene is heated to 10 ° C and 5 mol% of LiNH 3 is added. The mixture is further heated for 4 h at the same temperature, while the reaction ethanol is slowly distilled off. After the time has elapsed, the temperature is raised to 130-135 ° C and held for a further 6 h, thereby distilling off the remaining reaction ethanol. The solvent was distilled off in vacuo and the residue was subjected to high vacuum for 2 h.

The contents of the flask were allowed to cool, dissolved in 50 ml of toluene and washed three times with a small amount of water. The toluene solution is finally dried over anhydrous sodium sulfate and treated with activated charcoal. Evaporation of the solvent and exposure of the residue to high vacuum yields a solid, pulverizable polymer having a melting point in the range of 110-119 ° C and an average molecular weight of 1,350 (determined by VPO osmometer).

Elemental Analysis for ^ 40 ^ 62¾¾

Calculated: G 66.48%, H 8.59%, N 11.63

Found: C 66.22%, H 8.61%, N 11.73%.

Example 2

The procedure was as in Example 1 except that the reaction was carried out in the presence of 5 mol% sodium methoxide. After isolation, a polymer having a melting point of 115-124 ° C and an average molecular weight of 1,120 (determined by VPO osmometer) was obtained.

Elemontal analyzes for ^ 40 ^ 62 ^ 6 ^ 6

Calculated: Found:

C 66.48%, C 66.75%

H 8.59%, H 8.63%,

N 11, 63%, t 11.95%.

Claims (3)

SUBJECT INVENTION Polyamides of the sterically hindered piperazinediones type based on α, «-disubstituted dicarboxylic aliphatic acids containing in the macromolecule repeating structural elements of the general formula wherein Q is an alkylene chain having 2 to 6 carbon atoms, β has a value in the range of 0 to 6 and n is in the range of 2 to 10. 2. A process for the preparation of sterically hindered piperazinediones-type polyamides based on a, .alpha.-disubstituted dicarboxylic aliphatic acids according to claim 1, characterized in that to the compound of the formula EMI3.0 wherein R is alkyl of 1 to 2 carbon atoms, β is 0 to 6, such as ethylenediamine or hexamethylenediamine have aliphatic diamines having 2 to 6 carbon atoms. 3. The process of claim 2 wherein the reaction is carried out in the presence of basic catalysts such as lithium amide, tetrapropyltitanate and the reaction is carried out at a temperature in the range of from 100 to 150 ° C in a dry hydrocarbon solvent such as toluene, xylene and nitrobenzene. .