Methods of making a opaquely dark colored molding composition
View Patent ↗The invention relates to subduedly colored (brown, gray, black, green), infrared reflecting PMMA compounds which can be applied to other plastic compounds as an IR barrier layer.
1. A method of preparing an opaquely dark-colored molding composition, the method comprising
polymerizing a formulation to form the dark-colored molding composition; wherein the formulation comprises:
(a) a methyl (meth)acrylate monomer; and
(b) an IR-reflective pigment present in the amount of 0.05 to 5% by weight of the molding composition and which is selected from the group consisting of cobalt titanite green spinel having the CAS Number 68186-85-6, chromium oxide having the CAS Number 68909-79-5, iron chromite brown spinel having the CAS Number 68187-09-7, chromium iron oxide having the CAS Number 109414-04-2, nickel iron chromite black spinel having the CAS Number 71631-15-7, and combinations thereof; and
wherein the dark-colored molding composition exhibits a heating rate increase of less than 50° C./20 min irradiation, wherein the opaquely dark colored molding composition has a Cielab L* value below 41.
2. The method of preparing the opaquely dark-colored molding composition according to claim 1 , wherein the dark-colored molding composition exhibits a heating rate increase of less than 45° C./20 min when the molding composition is subjected to irradiation.
3. The method of preparing the opaquely dark-colored molding composition according to claim 1 , wherein the dark-colored molding composition exhibits a heating rate increase of less than 40° C./20 min when the molding composition is subjected to irradiation.
4. The method of preparing the opaquely dark-colored molding composition according to claim 1 , wherein the dark-colored molding composition further comprises:
(c) a mixture comprising:
(i) from 70 to 92% by weight, based on the total weight of the mixture, of styrene;
(ii) from 8 to 30% by weight, based on the total weight of the mixture, of acrylonitrile; and
(iii) optionally from 0 to 22% by weight, based on the total weight of the mixture, of a material selected from the group consisting of a monomer, an inorganic pigment, and combinations thereof.
5. The method of claim 1 , wherein the molding composition comprises the IR-reflective pigment cobalt titanite green spinel having the CAS Number 68186-85-6.
6. The method of claim 1 , wherein the molding composition comprises the IR-reflective pigment chromium oxide having the CAS Number 68909-79-5.
7. The method of claim 1 , wherein the molding composition comprises the IR-reflective pigment iron chromite brown spinel having the CAS Number 68187-09-7.
8. The method of claim 1 , wherein the molding composition comprises the IR-reflective pigment chromium iron oxide having the CAS Number 109414-04-2.
9. The method of claim 1 , wherein the molding composition comprises the IR-reflective pigment nickel iron chromite black spinel having the CAS Number 71631-15-7.
10. The method of claim 1 , wherein the dark-colored molding composition, when irradiated with a 60 W incandescent bulb with a voltage of 220 V, at a distance of 50 mm from the dark-colored molding composition, exhibits a heating rate increase of less than 50° C./20 min when the molding composition is subjected to irradiation.
11. An IR-reflective dark-colored molding composition, the composition comprising:
(a) polymethyl (meth)acrylate;
(b) a mixture comprising:
(i) from 70 to 72% by weight of the molding composition of polystyrene;
(ii) from 8 to 30% by weight of the molding composition of polyacrylonitrile;
(iii) optionally from 0 to 22% by weight of the molding composition of one or more
copolymers;
and
(c) an IR-reflective pigment selected from the group consisting of cobalt titanite green spinel having the CAS Number 68186-85-6, chromium oxide having the CAS Number 68909-79-5, iron chromite brown spinel having the CAS Number 68187-09-7, chromium iron oxide having the CAS Number 109414-04-2, nickel iron chromite black spinel having the CAS Number 71631-15-7, and combinations thereof,
wherein the dark-colored molding composition, when irradiated with a 60 W incandescent bulb with a voltage of 220 V, at a distance of 50 mm from the dark-colored molding composition, for 20 minutes, shows a temperature increase of 50° C. or less.