Polyester compounds suitable for hydroclaving

1. A polyester compound suitable for hydroclaving, comprising:

(1) polyester;

(2) polysulfone; and

(3) an oligomer which is a polymerization product of

(i) at least one epoxy-functional (meth)acrylic monomer; and

(ii) at least one styrene and/or (meth)acrylic monomer,

wherein the polysulfone has a weight of greater than 45 percent of weight of the compound, and

wherein the polyester comprises

(a) a dicarboxylic acid component comprising:

i) 70 to 100 mole % of terephthalic acid residues;

ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms other than terephthalic acid residues; and

iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and

(b) a glycol component comprising:

i) 1 to 99 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and

ii) 1 to 99 mole % of 1,4-cyclohexanedimethanol residues,

wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and

wherein the inherent viscosity of said polyester is from 0.35 to less than 0.70 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.; and

wherein said polyester has a Tg from 110 to 200° C.

2. The compound of claim 1 ,

wherein the polysulfone has a weight of at least 50 percent of weight of the compound and

wherein the polysulfone has a tensile strength at yield at 23° C. of 70-76 MPa, an elongation at break of 10-80%, a tensile modulus at 23° C. of 1.5-2.7 GPa, a long term service temperature range of 150° C.-180° C., and a heat deflection temperature at 1.8 MPa of 160° C.-174° C.

3. The compound of claim 1 , wherein

the polysulfone has a weight of at least 60 percent of weight of the compound and a repeating unit of

4. The compound of claim 1 , wherein the oligomer

has an epoxy equivalent weight of from about 180 to about 2800, a number-average epoxy functionality (Efn) value of less than about 30, a weight-average epoxy functionality (Efw) value of up to about 140, and a number-average molecular weight (Mn) value of less than 6000.

5. The compound of claim 4 , wherein the oligomer has a polydispersity index of from about 1.5 to about 5.

6. The compound of claim 4 , wherein the oligomer has a formula of

wherein R 1 -R 5 is H, CH 3 , a higher alkyl group having from 2 to 10 carbon atoms, or combinations thereof; and R 6 is an alkyl group; and wherein x, y, and z each is between 1 and 20.

7. The compound of claim 1 ,

wherein the compound further comprises optional additives selected from the group consisting of adhesion promoters; biocides; anti-fogging agents; anti-static agents; bonding, blowing and foaming agents; dispersants; fillers and extenders; fire and flame retardants and smoke suppressants; initiators; lubricants; micas; pigments, colorants and dyes; plasticizers; processing aids; release agents; silanes, titanates and zirconates; slip and anti-blocking agents; stabilizers; stearates; ultraviolet light absorbers; viscosity regulators; waxes; or combinations of them.

8. A plastic article molded from claim 1 .

9. The plastic article according to claim 8 , wherein the article endures successful repetitious hydroclaving of 135° C. temperature and 248 kPa of steam pressure for at least 18 minutes.

10. The plastic article of claim 9 , wherein the article is used in the medical industry and requires steam-based sterilization between each use.

11. The plastic article of claim 8 ,

wherein the polysulfone has a tensile strength at yield at 23° C. of 70-76 MPa, an elongation at break of 10-80%, a tensile modulus at 23° C. of 1.5-2.7 GPa, a long term service temperature range of 150° C.-180° C., and a heat deflection temperature at 1.8 MPa of 160° C.-174° C.

12. The plastic article of claim 8 ,

wherein the oligomer

has an epoxy equivalent weight of from about 180 to about 2800, a number-average epoxy functionality (Efn) value of less than about 30, a weight-average epoxy functionality (Efw) value of up to about 140, and a number-average molecular weight (Mn) value of less than 6000.

13. A method of hydroclaving the plastic article of claim 8 , comprising the steps of:

(a) heating a hydroclave chamber containing the plastic article to a temperature of 135° C.;

(b) maintaining the temperature of 135° C. at a steam pressure of at least 248 kPa; and

(c) cooling the chamber.

14. The method of claim 13 , wherein the plastic article endures successful repetitious hydroclaving of at least 35 cycles without deformation or stickiness.