Patent BG-109625-A (BG)
Title: Alkyd resins with waste polyethyleneterephtalate
Inventor: MIHIS Ana-Bianca
IPC: C08G63/00
Filed: 2006-07-18
Abstract: Alkyd resins containing waste polyethyleneterephtalate will find application in the production of air dried varnish and paint coatings used in everyday life as well as in industry. They have improved quality characteristics concerning the dry substance content, thus reducing the relative share of solvents in the end product; they do not contain any catalyst of the alcoholys is of the polyethyleneterephtalate, and the method of obtaining them runs without the participation of a catalyst. There is no catalyst in the composition of alkyd resins with waste polyethyleneterephtalate, and the weight ratio of the rest of the components is as follows: waste polyethyleneterephtalate from 4,0 to 15,0; polybasic acid, which is phthalic anhydride, from 10,0 to 20,0; alcohols, which are pentaerithritol, from 4,0 to 13,0; and trimethylolpropane from 3,0 to 15,0, as well as modifiers of the alkyd resin, which are vegetable fatty acids, from 15,0 to 65,0, or a mixture of vegetable fatty acids from 15 to 35 and vegetable oils from 20,0 to 40,0. The vegetable fatty acids are thalic and/or sunflower-seed, and the vegetable oils are sunflower-seed and/or soy-bean. The resins have acid number 7 mg KOH/g, dry residue 80 percent, resin viscosity in 50 percent solution in mineral turpentine under DIN 4 at 20 degrees C is 20-25 s. The method for obtaining the resins runs at two stages with no catalysts in the polyethyleneterephtalate alcoholysis. At the first stage, a reactor with nitrogen medium and supplied with a stirrer is charged with 2,0 to 7,5 parts by weight of pentaerithritol; the temperature is raised up to 200 degrees C, whereon there are dosed 4,0 to 15,0 parts by weight of waste polyethyleneterephtalate, the temperature is raised up to 240 degrees C and is kept at that level for 2 hours up to the end of the alcoholysis, preserving on-glass transparency for 30 min. The mixture is cooled down to 150 degrees C, there are charged 50,0 to 65,0 parts by weight of fatty acids and 12,0 to 19,9 parts by weight of phthalic anhydride, and the temperature is raised up to 160-170 degrees C and kept at that level for 1 hour, and after that it is cooled down to 130 degrees C. The second half of the pentaerithritol is charged in a quantity of 2,0 to 7,5 parts by weight, the temperature is raised up to 160 degrees C and kept at that level for 1,5 hour, whereupon the temperature is raised up to 240 degrees C at a speed of 20 degrees C/h, and when the temperature reaches 200 degrees C there is dosed 5 percent of the total mass of orthoxylene for azeotropic distillation up to reaching acid number 7 mg KOH/g, then it is diluted with mineral turpentine up to 80 percent of dry residue, resin viscosity in 50 percent solution in mineral turpentine under DIN 4 at 20 degrees C is 20-25 s. In a certain case, additional alcoholysis is carried out of vegetable oils in a quantity of 20,0 to 40,0 parts by weight with 4,0 to 13,0 parts by weight pentaerithritol at a temperature of 250 degrees C, and the process keeps running at that temperature up to achieving solubility of one part of reaction mixture with 6 parts of ethanol.