Phloroglucinolic resins, methods of making, and uses in rubber compositions
A solid phloroglucinolic resin comprises reacting a phloroglucinolic compound and a ketone in the presence of an acid catalyst. The solid phloroglucinolic resin formed includes multiple phloroglucinolic units defined by formula (I) wherein at least one of R1, R2, and R3 combines with a second phloroglucinolic unit to form a di-substituted methylene bridge, wherein the second one of R1, R2, and R3 is a hydrogen atom or combines with a third phloroglucinolic unit to form another di-substituted methylene bridge, and wherein the third one of R1, R2 and R3 is a hydrogen atom.
1 . The solid phloroglucinolic resin defined by formula (II)
wherein n is an integer from 1 to 20, wherein R1 and R3 may be the same or different, and each either form a di-substituted methylene bridge, or is a hydrogen atom, wherein R2 is a hydrogen atom, and wherein R4 and R5 may be the same or different, and are alkyl groups,
wherein the resin has a Mw of greater than 400 g/mole and less than 700 g/mole.
2 . The solid phloroglucinolic resin as claimed in claim 1 , wherein R4 and R5 are both methyl groups, and wherein the di-substituted methylene bridge formed is an isopropyliden bridge.
3 . The solid phloroglucinolic resin as claimed in claim 1 , wherein R4 is an ethyl group and R5 is a methyl group, and wherein the di-substituted methylene bridge formed is a 2,2 di-substituted butane bridge.
4 . The solid phloroglucinolic resin as claimed in claim 1 , wherein R4 is an isopropyl group and R5 is a methyl group, wherein the di-substituted methylene bridge formed is a 2,2 di-substituted, 4-methyl pentane bridge.
5 . A method for making the solid phloroglucinolic resin as claimed in claim 1 comprising the reaction product of a phloroglucinol and a ketone, defined as formula R4C(═O)R5, in the presence of an acid catalyst.
6 . The method of making the solid phloroglucinolic resin as claimed in claim 5 , wherein the ketone is selected from the group consisting of acetone, methyl ethyl ketone (MEK), diethyl ketone, ethyl butyl ketone, diisobutyl ketone, methyl isopropyl ketone, diisopropyl ketone, and methyl isobutyl ketone (MIBK).
7 . The method of making the solid phloroglucinolic resin as claimed in claim 5 , wherein the ketone is selected from the group consisting of acetone, methyl ethyl ketone, and methyl isobutyl ketone.
8 . The method of making the solid phloroglucinolic resin as claimed in claim 5 , wherein the acid catalyst is selected from the group consisting of inorganic acids and acid cation exchange resins.
9 . The method of making the solid phloroglucinolic resin as claimed in claim 5 , wherein a molar ratio of ketone to phloroglucinol is more than 1:1 and less than 20:1.
10 . The method of making the solid phloroglucinolic resin as claimed in claim 5 , wherein the resin includes less than 40 wt. % unreacted phloroglucinol.
11 . The solid phloroglucinolic resin as claimed in claim 1 , where the resin has a softening point of greater than 80° C.
12 . The solid phloroglucinolic resin as claimed in claim 1 , where the resin includes less than 1.5 wt. % water.
13 . The solid phloroglucinolic resin as claimed in claim 1 , where the resin has pentamer or higher oligomer content of less than 55% according to GPC using a polystyrene standard.
14 . A vulcanizable rubber composition comprising:
a. a vulcanizable rubber;
b. a curative; and
c. a solid phloroglucinolic resin as claimed in claim 1 .
15 . A vulcanized rubber prepared from the vulcanizable composition of claim 1 .
16 . A vulcanizable rubber composition comprising:
a vulcanizable rubber;
a curative; and
a solid phloroglucinolic resin which is made by the method as claimed in claim 5 .
17 . A vulcanized rubber prepared from the vulcanizable composition of claim 16 .
18 . The solid phloroglucinolic resin as claimed in claim 1 , wherein the resin includes less than 40 wt. % unreacted phloroglucinol.