Resins for improved flow in injection molding
Resins for improved flow in injection molding, molded articles made from the same, and methods of using the same. A molded article formed from a polymer feed includes nylon-6,6. The molded article also includes a thin elongated profile including a thickness of up to 1.5 mm and a flow length of at least 25 cm. An absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 5, the RV determined according to ASTM D789.
1. A method of making a molded article, the method comprising:
molding a polymer feed comprising nylon-6,6 in a mold to form the molded article without raising the temperature of the polymer feed above 320° C.; and
recovering the molded article from the mold, the molded article comprising
nylon-6,6, and
a section having a thin elongated profile comprising
a thickness of up to 1.5 mm, and
a flow length of at least 25 cm;
wherein
an absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4.8, the RV determined according to ASTM D789,
the polymer feed comprises a polyamide resin having a moisture content of 0.03 to 0.20 wt %, the polyamide resin comprising
from 90 to 99.9 wt. % polyamide condensation product of diacid and diamine,
from 3 to 200 ppmw phosphorus, present as an oxyphosphorus compound,
from 800 to 3000 ppmw acetic acid end groups on the polyamide, and
amine end groups (AEG)<N milliequivalents per kg (meq/kg) of the polyamide resin, where N is selected from integers from 40 to 50, inclusive,
the polyamide resin has a RV from 26 to 42, the RV determined according to ASTM D789, and
the method is sufficient such that if the moisture content of the polymer feed is 0.14 wt %, then the absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4.8, the RV determined according to ASTM D789.
2. The method of claim 1 , further comprising
regulating the mold temperature via heat exchange with water at inlet temperature of water to the mold below 100° C.; and
recovering the molded article from the mold, wherein an absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4.8, the RV determined according to ASTM D789.
3. The method of claim 1 , wherein the nylon-6,6 is at least 80 wt. % of the molded article.
4. The method of claim 1 , wherein the RV of the polymer feed is from ≥30 to ≤38, the RV determined according to ASTM D789.
5. The method of claim 1 , wherein the section having the thin elongated profile is 0.001 vol % to 100 vol % of the molded article.
6. The method of claim 1 , wherein the section having the thin elongated profile is 100 vol % of the molded article.
7. The method of claim 1 , wherein the flow length is from ≥30 cm to ≤90 cm.
8. The method of claim 1 , wherein the section having the thin elongated profile has a thickness of from 0.1 mm to 1.5 mm.
9. The method of claim 1 , wherein the diacid is adipic acid and the diamine is hexamethylenediamine.
10. The method of claim 1 , wherein the molded article has:
a tensile strength (ISO 527, dry-as-molded specimens) of at least 80 MPa, and
an unnotched Charpy impact energy (ISO 179, dry-as-molded specimens) of at least 100 kJ/m 2 .
11. The method of claim 1 , wherein the polyimide resin further comprises at least one copolyamide.
12. The method of claim 1 , wherein the polyamide resin has amine end groups (AEG) below 40 milliequivalents per kg (meq/kg) of the polyamide resin.
13. The method of claim 1 , wherein the diacid is adipic acid and the diamine is hexamethylenediamine.
14. The method of claim 1 , wherein the molded article has:
a tensile strength (ISO 527, dry-as-molded specimens) of at least 80 MPa, and
an unnotched Charpy impact energy (ISO 179, dry-as-molded specimens) of at least 100 kJ/m 2 .
15. The method of claim 1 , wherein the polyamide resin further comprises at least one copolyamide.
16. A method of making a molded article, the method comprising:
molding a polymer feed comprising nylon-6,6 to form the molded article without raising the temperature of the polymer feed above 315° C., wherein the molded article comprises
nylon-6,6, and
a section having a thin elongated profile comprising
a thickness of up to 1.5 mm, and
a flow length of at least 25 cm;
wherein
an absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4.8, the RV determined according to ASTM D789,
the polymer feed comprises a polyamide resin having a moisture content of 0.03 to 0.20 wt %, the polyamide resin comprising
from 90 to 99.9 wt. % polyamide condensation product of diacid and diamine,
from 3 to 200 ppmw phosphorus, present as an oxyphosphorus compound,
from 800 to 3000 ppmw acetic acid end groups on the polyamide, and
amine end groups (AEG)<N milliequivalents per kg (meq/kg) of the polyamide resin, where N is selected from integers from 40 to 50, inclusive,
the polyamide resin has a RV from 26 to 42, the RV determined according to ASTM D789, and
the method is sufficient such that if the moisture content of the polymer feed is 0.14 wt %, then the absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4.8, the RV determined according to ASTM D789.
17. A method for making a molded article comprising:
molding a polymer feed comprising nylon-6,6 in a mold to form the molded article without raising the temperature of the polymer feed above 320° C., wherein
the polymer feed comprises a polyamide resin having a moisture content of 0.03 to 0.20 wt %, the polyamide resin comprising
from 90 to 99.9 wt. % polyamide condensation product of diacid and diamine,
from 3 to 200 ppmw phosphorus, present as an oxyphosphorus compound,
from 800 to 3000 ppmw acetic acid end groups on the polyamide, and
amine end groups (AEG)<N milliequivalents per kg (meq/kg) of the polyamide resin, where N is selected from integers from 40 to 50, inclusive, and
the polyamide resin has a RV from 26 to 42, the RV determined according to ASTM D789;
regulating the mold temperature via heat exchange with water at inlet temperature of water to the mold below 100° C.; and
recovering a molded article from the mold, wherein an absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4.8, the RV determined according to ASTM D789;
wherein the molded article comprises
nylon-6,6, and
a section having a thin elongated profile comprising
a thickness of up to 1.5 mm, and
a flow length of at least 25 cm, and
wherein the method is sufficient such that if the moisture content of the polymer feed is 0.14 wt % then the absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4.8, the RV determined according to ASTM D789.
18. The method of claim 1 , wherein an absolute value of ΔRV of the molded article as compared to the polymer feed is from 0 to 4, the RV determined according to ASTM D789.
19. The method of claim 1 , comprising molding the polymer feed comprising nylon-6,6 to form the molded article without raising the temperature of the polymer feed above 310° C.