Thermoplastic composition having improved X-ray contrast, method of making, and articles prepared therefrom

1. A mold comprising a thermoplastic composition comprising:

polysiloxane-polycarbonate,

optionally, polycarbonate, and

an X-ray contrast agent comprising X-ray scattering atoms having an atomic number of greater than or equal to 22,

wherein each of the polysiloxane-polycarbonate, polycarbonate, and X-ray contrast agent are present based on a combined 100 parts by weight of polysiloxane-polycarbonate and polycarbonate,

wherein an article molded from the thermoplastic composition and having a thickness of 3.2 mm has a notched Izod impact (NII) strength of greater than or equal to about 620 J/m, when measured at a temperature of 0° C. according to ASTM D256-04, or a notched Izod impact strength of greater than or equal to about 409 J/m, when measured at a temperature of −30° C. according to ASTM D256-04,

wherein the article molded from the thermoplastic composition and having a thickness of 3.2 mm has an Equivalent Al Thickness of greater than 0.51 mm, when irradiated with 50 kV X-ray radiation, and

wherein a melt volume rate of the thermoplastic composition measured at a dwell time of 18 minutes increases relative to a melt volume rate of the thermoplastic composition measured at a dwell time of 6 minutes by less than or equal to 31%, wherein the melt volume rates are determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04,

wherein the X-ray scattering agent has a particle size of less than about 5 micrometers, and

wherein degradation of the mold is detectable via X-ray.

2. The mold of claim 1 , comprising polysiloxane-polycarbonate in an amount of 5 to 100 parts by weight, and polycarbonate in an amount of 0 to 95 parts by weight, based on combined 100 parts by weight of polysiloxane-polycarbonate and any added polycarbonate.

3. The mold of claim 2 , wherein the polysiloxane-polycarbonate comprises 50 to 99.9 wt % of carbonate units and 0.1 to 50 wt % siloxane units, based on the total weight of the polysiloxane-polycarbonate.

4. The mold of claim 1 , comprising polysiloxane-polycarbonate in an amount of 50 to 99 parts by weight, and polycarbonate in an amount of 1 to 50 parts by weight based on a combined 100 parts by weight of polysiloxane-polycarbonate and any added polycarbonate.

5. The mold of claim 4 , wherein the polysiloxane-polycarbonate comprises 90 to 99 wt % of carbonate units and 1 to 10 wt % siloxane units, based on the total weight of the polysiloxane-polycarbonate.

6. The mold of claim 1 , wherein the thermoplastic composition comprises polysiloxane-polycarbonate in an amount of 5 to 30 parts by weight, and polycarbonate in an amount of 70 to 95 parts by weight based on a combined 100 parts by weight of polysiloxane-polycarbonate and any added polycarbonate.

7. The mold of claim 6 , wherein the polysiloxane-polycarbonate comprises 75 to 85 wt % of carbonate units and 15 to 25 wt % siloxane units, based on the total weight of the polysiloxane-polycarbonate.

8. The mold of claim 1 , wherein the thermoplastic composition comprises the X-ray contrast agent in an amount of about 0.01 to about 10 parts by weight, based on a combined 100 parts by weight of polysiloxane-polycarbonate and any added polycarbonate.

9. The mold of claim 1 , wherein the X-ray contrast agent comprises X-ray scattering atoms having an atomic number of greater than or equal to 24.

10. The mold of claim 1 , wherein the X-ray contrast agent comprises X-ray scattering atoms in an amount greater than or equal to about 1 percent by weight, based on the total weight of the X-ray contrast agent.

11. The mold of claim 1 , wherein the X-ray contrast agent comprises magnetite or rutile titanate.

12. The mold of claim 11 , wherein the rutile titanate comprises Pigment Yellow 53, Pigment Yellow 163, Pigment Brown 24, or a combination comprising at least one of the foregoing.

13. The mold of claim 1 , wherein for melt volume rates of the composition determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04, a melt volume rate measured at a dwell time of 18 minutes differs from a melt volume rate measured at a dwell time of 6 minutes by less than or equal to 20%.

14. The mold of claim 1 , wherein the thermoplastic composition has a siloxane content of 1 to 6 wt %, based on the total weight of the thermoplastic composition.

15. The mold of claim 1 , wherein the thermoplastic composition further comprises additives including impact modifiers, fillers, antioxidants, heat stabilizers, light, stabilizers, UV light stabilizers, plasticizers, lubricants, mold release agents, flame retardants, antistatic agents, anti-drip agents, radiation stabilizers, or a combination comprising at least one of the foregoing additives.

16. The mold of claim 1 , wherein an article molded from the thermoplastic composition and having a thickness of 3.2 mm has an Equivalent Al Thickness of greater than 0.55 mm, when irradiated with 50 kV X-ray radiation.

17. The mold of claim 1 , wherein the surface gloss of the thermoplastic composition, measured at an angle of 60 degrees on 3 mm colored chips, is greater than or equal to 90 gloss units, according to ASTM D2457.

18. The mold of claim 1 , wherein the mold is a mold for the food service industry, a medical device, or a toy.

19. A mold comprising a thermoplastic composition comprising:

a) 5 to 100 parts by weight of a polysiloxane-polycarbonate,

b) 0 to 95 parts by weight of a polycarbonate, and

c) 0.01 to 10 parts by weight of an X-ray contrast agent comprising rutile titanate having a median particle size of less than or equal to about 5 micrometers, magnetite having a median particle size of less than about 1 micrometer, or a combination comprising at least one of the foregoing contrast agents,

wherein each of the polysiloxane-polycarbonate, polycarbonate, and X-ray contrast agent are present based on a combined 100 parts by weight of polysiloxane-polycarbonate and polycarbonate,

wherein an article molded from the thermoplastic composition and having a thickness of 3.2 mm has a notched Izod impact (NII) strength of greater than or equal to about 620 J/m, when measured at a temperature of 0° C. according to ASTM D256-04, or a notched Izod impact strength of greater than or equal to about 409 J/m, when measured at a temperature of −30° C. according to ASTM D256-04,

wherein the article molded from the thermoplastic composition and having a thickness of 3.2 mm has an Equivalent Al Thickness of greater than 0.51 mm, when irradiated with 50 kV X-ray radiation, and

wherein for melt volume rates of the thermoplastic composition determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04, a melt volume rate measured at a dwell time of 18 minutes increases relative to a melt volume rate measured at a dwell time of 6 minutes by less than or equal to 31%,

wherein degradation of the mold is detectable via X-ray.

20. The mold of claim 19 , wherein the polysiloxane-polycarbonate has an average block length D for a polysiloxane unit of the polysiloxane-polycarbonate of about 5 to about 50 siloxane units.

21. The mold of claim 19 , comprising 1 to 10 parts by weight of rutile titanate.

22. A mold for manufacturing chocolate, comprising a thermoplastic composition comprising:

a) 5 to 99 parts by weight of a polysiloxane-polycarbonate,

b) 1 to 95 parts by weight of a polycarbonate, and

c) 0.01 to 10 parts by weight of an X-ray contrast agent comprising rutile titanate having a median particle size of less than or equal to about 5 micrometers, magnetite having a median particle size of less than or equal to about 0.5 micrometers, or a combination comprising at least one of the foregoing X-ray contrast agents,

wherein each of the polysiloxane-polycarbonate, polycarbonate, and X-ray contrast agent are present based on a combined 100 parts by weight of polysiloxane-polycarbonate and polycarbonate,

wherein an article molded from the thermoplastic composition and having a thickness of 3.2 mm has a notched Izod impact (NII) strength of greater than or equal to about 620 J/m, when measured at a temperature of 0° C. according to ASTM D256-04, or a notched Izod impact strength of greater than or equal to about 409 J/m, when measured at a temperature of −30° C. according to ASTM D256-04,

wherein the article molded from the thermoplastic composition and having a thickness of 3.2 mm has an Equivalent Al Thickness of greater than 0.51 mm, when irradiated with 50 kV X-ray radiation, and

wherein for melt volume rates of the thermoplastic composition determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04, a melt volume rate measured at a dwell time of 18 minutes increases relative to a melt volume rate measured at a dwell time of 6 minutes by less than or equal to 31%; and

wherein degradation of the mold is detectable via X-ray.

23. A mold comprising a thermoplastic composition comprising:

a) polysiloxane-polycarbonate,

b) optionally, polycarbonate, and

c) an X-ray contrast agent comprising X-ray scattering atoms having an atomic number of greater than or equal to 22,

wherein each of the polysiloxane-polycarbonate, polycarbonate, and X-ray contrast agent are present based on a combined 100 parts by weight of polysiloxane-polycarbonate and polycarbonate,

wherein an article molded from the thermoplastic composition and having a thickness of 3.2 mm has a notched Izod impact (NII) strength of greater than or equal to about 620 J/m, when measured at a temperature of 0° C. according to ASTM D256-04, or a notched Izod impact strength of greater than or equal to about 409 J/m, when measured at a temperature of −30° C. according to ASTM D256-04,

wherein the article molded from the thermoplastic composition and having a thickness of 3.2 mm has an Equivalent Al Thickness of greater than 0.51 mm, when irradiated with 50 kV X-ray radiation, and

wherein for melt volume rates of the thermoplastic composition determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04, a melt volume rate measured at a dwell time of 18 minutes increases relative to a melt volume rate measured at a dwell time of 6 minutes by less than or equal to 31%, and

wherein degradation of the mold is detectable via X-ray,

wherein the X-ray contrast agent has a median particle size of 0.1 micrometers to 5 micrometers.

24. The mold of claim 23 , wherein the X-ray contrast agent has a median particle size of 0.2 to 0.5 micrometers.

25. A method for increasing the x-ray contrast in an article comprising a thermoplastic composition, comprising

combining

an X-ray contrast agent having a median particle size of less than or equal to 5 micrometers, with

a polysiloxane-polycarbonate, and optionally a polycarbonate,

wherein the X-ray contrast agent comprises an element having an atomic number of greater than or equal to 22, and

wherein each of the polysiloxane-polycarbonate, polycarbonate, and X-ray contrast agent are present based on a combined 100 parts by weight of polysiloxane-polycarbonate and polycarbonate; and

forming the article from the thermoplastic composition,

wherein the article molded from the thermoplastic composition, when it has a thickness of 3.2 mm has a notched Izod impact (NII) strength of greater than or equal to about 620 J/m, when measured at a temperature of 0° C. according to ASTM D256-04, or notched Izod impact strength of greater than or equal to about 409 J/m, when measured at a temperature of −30° C. according to ASTM D256-04,

wherein the article molded from the thermoplastic composition, when it has a thickness of 3.2 mm has an Equivalent Al Thickness of greater than 0.51 mm, when irradiated with 50 kV X-ray radiation, and

wherein for melt volume rates of the thermoplastic composition determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04, a melt volume rate measured at a dwell time of 18 minutes increases relative to a melt volume rate measured at a dwell time of 6 minutes by less than or equal to 31%.

26. A method for forming an article, comprising

molding the article in a mold, wherein the mold was formed from a thermoplastic composition, comprising

polysiloxane-polycarbonate, optionally, polycarbonate, and

an X-ray contrast agent comprising X-ray scattering atoms having an atomic number of greater than or equal to 22 and having a median particle size of less than or equal to 5 micrometers,

wherein each of the polysiloxane-polycarbonate, polycarbonate, and X-ray contrast agent are present based on a combined 100 parts by weight of polysiloxane-polycarbonate and polycarbonate

wherein the mold, at a thickness of 3.2 mm, has a notched Izod impact (NII) strength of greater than or equal to about 620 J/m, when measured at a temperature of 0° C. according to ASTM D256-04, or a notched Izod impact strength of greater than or equal to about 409 J/m, when measured at a temperature of −30° C. according to ASTM D256-04,

wherein the mold, at a thickness of 3.2 mm, has an Equivalent Al Thickness of greater than 0.51 mm, when irradiated with 50 kV X-ray radiation, and

wherein a melt volume rate of the thermoplastic composition measured at a dwell time of 18 minutes increases relative to a melt volume rate of the thermoplastic composition measured at a dwell time of 6 minutes by less than or equal to 31%, wherein the melt volume rates are determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04; and

releasing the article from the mold.

27. The method of claim 26 , wherein the article is a candy.

28. A method for molding chocolate,

comprising

molding the chocolate in a mold, wherein the mold was formed from a thermoplastic composition, comprising

polysiloxane-polycarbonate,

optionally, polycarbonate, and

an X-ray contrast agent comprising X-ray scattering atoms having an atomic number of greater than or equal to 22 and having a median particle size of less than or equal to 5 micrometers,

wherein each of the polysiloxane-polycarbonate, polycarbonate, and X-ray contrast agent are present based on a combined 100 parts by weight of polysiloxane-polycarbonate and polycarbonate,

wherein the mold, at a thickness of 3.2 mm, has a notched Izod impact (NII) strength of greater than or equal to about 620 J/m, when measured at a temperature of 0° C. according to ASTM D256-04, or a notched Izod impact strength of greater than or equal to about 409 J/m, when measured at a temperature of −30° C. according to ASTM D256-04,

wherein the mold, at a thickness of 3.2 mm, has an Equivalent Al Thickness of greater than 0.51 mm, when irradiated with 50 kV X-ray radiation, and

wherein a melt volume rate of the thermoplastic composition measured at a dwell time of 18 minutes increases relative to a melt volume rate of the thermoplastic composition measured at a dwell time of 6 minutes by less than or equal to 31%, wherein the melt volume rates are determined under a load of 1.2 kg at a temperature of 300° C. according to ASTM D1238-04; and

releasing the chocolate from the mold.

29. The method of claim 28 , further comprising X-raying the chocolate to determine degradation of the mold.