Compositions containing rosin esters
Disclosed are compositions which include an ethylene polymer derived from at least one polar monomer with one or more ester groups, and a rosin ester. The rosin ester can have a low hydroxyl number (e.g., a hydroxyl number seven or less), a low acid number (e.g., an acid number of ten or less), a relatively low PAN number (e.g., a PAN number less than twenty-five), a relatively high third moment or third power average molecular weight (Mz), (e.g., an Mz value in between 2500 and 12000 g/mol), a low sulfur content (e.g., a sulfur content lower than 600 ppm prior to antioxidant addition) or combinations thereof. The compositions can exhibit a high heat stress resistance (e.g., a heat stress pass temperature value higher than 52° C. or in between 48° C. and 60° C.) and/or improved viscosity stability and/or color stability upon thermal aging and/or improved compatibility.
1. A rosin ester derived by esterification of a rosin, wherein the rosin ester is prepared by a process consisting essentially of:
contacting reactants consisting essentially of a rosin, a carboxylic acid moiety, and an alcohol at a temperature of at least 170° C.;
esterifying the reactants at a maximum temperature of 300° C. in the absence or presence of an esterification catalyst and in the absence of a disproportionation catalyst, or with less than 0.05% by weight of a disproportionation catalyst, to form a rosin ester; and
stripping off residual reactants and volatiles to recover the rosin ester;
wherein the recovered rosin ester has
a hydroxyl number of seven or less,
a M z value between 2500 and 12000 g/mol according to ASTM D5296-05,
a sulfur ppm content of <1000 ppm,
a softening point of >100° C.,
a PAN number of <25.
2. The rosin ester of claim 1 , wherein the process for preparing the rosin ester further comprises adding an antioxidant or an additive to the recovered rosin ester.
3. The rosin ester of claim 1 , wherein the reactants consists essentially of a rosin, a carboxylic acid moiety, and an alcohol, wherein the reactants contain a stoichiometric excess of carboxylic acid functionality as compared to the total stoichiometric amount of hydroxyl functionality.
4. The rosin ester of claim 1 , wherein the rosin ester comprising less than 40 wt. % esterified dehydroabietic acid.
5. The rosin ester of claim 4 , wherein the rosin ester has a ratio of esterified dehydroabietic acid to the PAN number of less than 5.
6. The rosin ester of claim 1 , wherein the rosin ester has an acid number of 10 or less.
7. The rosin ester of claim 6 , wherein sum of the hydroxyl number and the acid number is 12 or less.
8. The rosin ester of claim 1 , wherein the rosin ester has zero to up to 10 wt. % tetrahydroabietic acid.
9. The rosin ester of claim 1 , wherein the rosin ester has a Mw value of 1700 to 4000 g/mol, and a Mn value of 1100 to 2000 g/mol.
10. The rosin ester of claim 1 , wherein the rosin ester has a softening point higher than 105.3° C. and lower than 110° C.
11. The rosin ester of claim 1 , wherein the rosin is a tall oil rosin.
12. The rosin ester of claim 1 , wherein the rosin ester, after thermal aging at 177° C. for 10 hours, has a turbidimetric light transmission percentage that exceeds 75% within a temperature range of 80° C. to 180° C.
13. The rosin ester of claim 1 , wherein the reactants contain more than zero up to 10 weight %, relative to the total weight of the reactants, of one or more dicarboxylic acid functional organic compounds.
14. The rosin ester of claim 1 , wherein the reactants contain more than zero up to 10 weight %, relative to the total weight of the reactants, of a saturated aliphatic difunctional carboxylic acid selected from the group consisting of succinic acid, glutaric acid, adipic acid, sebacic acid, or 1,4-cyclohexanedicarboxylic acid, and combinations of these acids.
15. A composition comprising the rosin ester of claim 1 , wherein the composition is a thermoplastic road marking formulation, a tire formulation or an adhesive formulation.
16. A method of making a rosin ester, the method comprising:
providing a reactant mixture consisting essentially of a rosin, a carboxylic acid moiety, and an alcohol;
esterifying the reactant mixture at a maximum temperature of 300° C. in the absence or presence of an esterification catalyst and in the absence of a disproportionation catalyst, or with less than 0.05% by weight of a disproportionation catalyst, to form a rosin ester;
optionally adding an antioxidant or an additive to the rosin ester; and
recovering a rosin ester having
a hydroxyl number of seven or less,
a M z value between 2500 and 12000 g/mol according to ASTM D5296-05
a sulfur ppm content of <1000 ppm,
a softening point of >100° C.,
a PAN number of <25,
less than 40 wt. % esterified dehydroabietic acid, and
a ratio of esterified dehydroabietic acid to the PAN number of less than 5.