NOVEL BIOBIASED POLYESTER
A novel linear polyester resin is made by condensation of one or more aliphatic or cycloaliphatic polyols with one or more aliphatic or cycloaliphatic polyfunctional acids derived from biobased materials or a biological feedstock. Coating compositions and coated substrates using the novel linear polyester resin are also described.
1 . A coating composition, comprising:
a binder comprising
a linear polyester resin having number average molecular weight (Mn) of at least about 1000, hydroxyl equivalent weight of at least about 1000 mg KOH per gram, and less than about 5 percent by weight aromatic groups; and
optionally, a curing agent capable of reacting with the linear polyester resin to produce a crosslinked polymeric network; and
at least one pigment.
2 . The composition of claim 1 , wherein the linear polyester resin has Mn of about 1500 to about 6000.
3 . The composition of claim 1 , wherein the linear polyester resin has Mn of about 3000 to about 5000.
4 . The composition of claim 1 , wherein the linear polyester resin is substantially free of aromatic groups.
5 . The composition of claim 1 , wherein the linear polyester resin is substantially free of cycloaliphatic groups.
6 . The composition of claim 1 , wherein the linear polyester resin has hydroxyl number of about 1000 to 2000 mg KOH per gram.
7 . The composition of claim 1 , wherein the linear polyester resin has hydroxyl number of about 1200 to 1600 mg KOH per gram.
8 . The composition of claim 1 , wherein the linear polyester resin is derived from the reaction of an aliphatic diol with an aliphatic diacid.
9 . The composition of claim 6 , wherein the aliphatic diol is tetramethylpentanediol.
10 . The composition of claim 8 , wherein the aliphatic diacid has a structure of a compound of Formula (I):
R 1 O—C(═O)-(A) n -C(═O)—OR 2 (I)
wherein
R1 and R2 are each independently H, C1-C6 alkyl, or C2-C6 alkylene;
A is a divalent organic group of formula C1-C10 alkyl, C2-C10 alkylene, or C3-C10 cycloalkyl; and
n is an integer between 1 and 20.
11 . The composition of claim 10 , wherein R1 and R2 are each independently H, A is —CH 2 — and n is a number between 2 and 4.
12 . The composition of claim 10 , wherein the aliphatic diacid of Formula I is succinic acid.
13 . The composition of claim 10 , wherein the aliphatic diacid is derived from bio-based material.
14 . The composition of claim 12 , wherein the aliphatic diacid is succinic acid.
15 . The composition of claim 1 , wherein the linear polyester resin has Tg of greater than −10° C.
16 . The composition of claim 1 , wherein the linear polyester resin has Tg of about −30° C. to about 20° C.
17 . The composition of claim 1 , wherein the linear polyester resin has low solution viscosity.
18 . The composition of claim 17 , wherein the linear polyester resin has low solution viscosity of about 4000 to 5000 cps.
19 . A method of making a coated article, comprising:
providing a substrate;
applying to the substrate a coating composition comprising
a binder comprising
a linear polyester resin having number average molecular weight (Mn) of at least about 1000, hydroxyl equivalent weight of at least 1000 mg KOH per gram, and less than 5 percent by weight aromatic groups; and
optionally, a curing agent capable of reacting with the linear polyester resin to produce a crosslinked polymeric network; and
at least one pigment; and
curing the coating composition on the substrate to provide the coated article.
20 . A coated article, comprising:
a substrate; and
a cured coating formed on the substrate, wherein the cured coating is formed from a coating composition comprising
a binder comprising
a linear polyester resin having number average molecular weight (Mn) of at least about 1000, hydroxyl equivalent weight of at least 1000 mg KOH per gram, and less than 5 percent by weight aromatic groups; and
optionally, a curing agent capable of reacting with the linear polyester resin to produce a crosslinked polymeric network; and
at least one pigment.