Transparent polyester resins and articles therefrom
View Patent ↗Compositions suitable for preparing transparent articles comprising an aromatic polyester resin selected from a copolyalkylene terephthalate containing from 3 to 15% by moles of units derived from isophtalic acid and/or a naphtalene dicarboxylic acid and a polyxylylene amide, preferably poly (m.xylylene adipamide), in which the polymide is dispersed in the polyester resin as domains with average numeral size of 30 to 200 nm. The compositions are obtained by premelt-mixing the polyester with a dianhydride of a tetracarboxylic acid prior mixing the polyxylylene amide using melt viscosity ration between the polyester resin and the polyxylylene amide higher that 1.5:1, preferably from 3:1 to 8:1.
1. A composition for preparing articles having high transparency comprising an aromatic polyester resin and a polyxylylene amide, in which the aromatic polyester resin is selected from the copolyalkylene terephthalates containing from 3 to 15% by mols of units derived from isophthalic acid and/or napthalene dicarboxylic acids and wherein the polyxylylene amide is dispersed in the aromatic polyester resin matrix as domains having an average particle size which is within the range of 30 nm to 110 nm.
2. A composition according to claim 1 , in which the polyxylylene amide is poly(m-xylylene adiparnide) used in amount of 1 to 15% by weight relative to the polyester resin.
3. A composition according to claim 2 wherein the aromatic polyester resin is selected from copolyalkylene terephthalates containing from 4 to 7% by moles of units derived from isophthalic acid and/or naphthalene dicarboxylic acids.
4. A composition according to claim 3 in which the ratio of the melt viscosity of the poly(m-xylylene adipamide) to the melt viscosity of the copolyalkylene terephthalate is 1:3 to 1:8.
5. A composition according to claim 2 in which the ratio of the melt viscosity of the poly(m-xylylene adipamide) to the melt viscosity of the copolyalkylene terephthalate is 1:3 to 1:8.
6. An article having haze less than 3% obtained from the compositions according to claim 1 .
7. A film or container according to claim 1 , in which the polyxylylene adipamide is poly(m-xylylene adipamide).
8. A composition according to claim 1 wherein the domains have an average numeral size of 80 to 100 nm, and wherein more than 80% of the domains have a size of 80 to 110 nm.
9. A composition according to claim 8 , in which the polyxylylene amide is poly(m-xylylene adipamide) used in amount of 1 to 15% by weight relative to the polyester resin.
10. A composition according to claim 9 wherein the polyester resin is selected from copolyalkylene terephthalates containing from 4 to 7% by moles of units derived from isophthalic acid and/or naphthalene dicarboxylic acids.
11. An article having haze less than 3% obtained from the compositions according to claim 8 .
12. A composition according to claim 8 in which the ratio of the melt viscosity of the polyamide to the melt viscosity of the copolyalkylene terephthalate is 1:3 to 1:8.
13. A process for preparing compositions according to claim 1 in which the copolyalkylene terephthalate containing from 3 to 15% by mols of units derived from isophthalic acid and/or naphthalene dicarboxylic acids is melt-mixed with a dianhydride of a tetracarboxylic acid in amount from 0.02 to 0.4 wt% on the polyester resin and subsequently is mixed with the polyxylylene amide having melt viscosity referred to that of the polyalkylene terephthalate in a ratio of 1:3 to 1:8.
14. A composition according to claim 1 wherein the aromatic polyester resin is selected from copolyalkylene terephthalates containing from 4 to 7% by moles of units derived from isophthalic acid and/or naphthalene dicarboxylic acids.
15. A composition according to claim 1 in which the ratio of the melt viscosity of the polyxylylene amide to the melt viscosity of the copolyalkylene terephthalateis 1:3 to 1:8.
16. A composition according to claim 1 wherein the polyxylylene amide is dispersed in the aromatic polyester resin matrix as domains having an average particle size which is within the range of 30 nm to 100 nm.
17. A film or container having haze less than 3% obtained from the composition according to claim 8 and in which the polyxylylene amide is dispersed in the polyester matrix in domains having average numeral size of 80 to 100 nm, wherein more than 80% of the domains have a size of 80 to 100 nm.
18. A film or container according to claim 17 , in which the polyxylylene amide is poly(m-xylylene adipamide).
19. An article according to claim 17 in which the ratio of the melt viscosity of the polyamide to the melt viscosity of the copolyalkylene terephthalate is 1:3 to 1:8.
20. A composition for preparing articles having high transparency comprising (1) a copolyalkylene terephthalates containing monomeric units that are derived from isophthalic acid and/or napthalene dicarboxylic acids and (2) a polyxylylene amide, wherein the polyxylylene amide is dispersed in the aromatic polyester resin matrix as domains having an average particle size which is within the range of 30 nm to 110 nm.
21. A composition according to claim 20 , in which the polyxylylene amide is poly(m-xylylene adipamide) used in amount of 1 to 15% by weight relative to the polyester resin.
22. A composition according to claim 21 wherein the polyxylylene amide is dispersed in the aromatic polyester resin matrix as domains having an average particle size which is within the range of 30 nm to 100 mm.
23. A composition according to claim 20 wherein the polyxylylene amide is dispersed at a level within the range of 1 weight percent to 15 weight percent relative to the polyester copolyalkylene terephthalate resin.