Modified phenolic novolak resins and applications thereof
View Patent ↗A modified phenolic novolak resin is prepared by reacting a phenolic compound (e.g., resorcinol) with an aliphatic polyol. The reaction mixture further reacts with a formaldehyde to produce a modified phenolic novolak resin. The reaction is typically carried out in the presence of an acid or a base catalyst. The resulting resin is characterized by a relatively low level of free resorcinol; and rubber compounds containing the resin exhibit low fuming, lower Mooney viscosity (which means better processing), better dynamic stiffness properties (G′), and/or good tear properties. Therefore, the resulting resin can be used as a methylene acceptor compound in a vulcanizable rubber composition.
1. A modified phenolic novolak resin obtained by reacting a phenolic compound with an aliphatic polyol and an aldehyde in the presence of an acid catalyst at a pH less than 7.
2. The modified phenolic novolak resin of claim 1 , wherein the mole ratio of the aldehyde to the phenolic compound is less than 0.9:1.
3. The modified phenolic novolak resin of claim 1 , wherein the mole ratio of the aldehyde to the phenolic compound is less than 0.8:1.
4. The modified phenolic novolak resin of claim 1 , wherein the mole ratio of the aldehyde to the phenolic compound is between about 0.2:1 and about 0.5:1.
5. The modified phenolic novolak resin of claim 1 , wherein the acid catalyst is selected from the group consisting of benzenesulfonic acid, benzene-1,2-disulfonic acid, benzene-1,3-disulfonic acid, benzene-1,4-disulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, oxalic acid, methanesulfonic acid, 4-chlorobenzenesulfonic acid and combinations thereof.
6. The modified phenolic novolak resin of claim 1 , wherein the pH is less than 4.
7. The modified phenolic novolak resin of claim 1 , wherein the phenolic compound is represented by Formula (I)
wherein each of R 1 , R 2 , R 3 , R 4 and R 5 is independently H, hydroxyl, thiol, amido, halogen, cyano, nitro, amino, acyl, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aralkyl, alkenyl, alkynyl, alkoxy, aryloxy, acyloxy, acylamino, alkoxycarbonyl or a part of a ring where two of R 1 , R 2 , R 3 , R 4 and R 5 together from the ring with the proviso that at least two of R 1 , R 2 , R 3 , R 4 and R 5 are H.
8. The modified phenolic novolak resin of claim 7 , wherein R 2 is hydroxyl.
9. The modified phenolic novolak resin of claim 1 , wherein the phenolic compound is an unsubstituted resorcinol or a substituted resorcinol.
10. The modified phenolic novolak resin of claim 1 , wherein the aliphatic polyol is an aliphatic diol.
11. The modified phenolic novolak resin of claim 10 , wherein the mole ratio of the phenolic compound to the aliphatic diol is between about 1:0.3 and about 1:1.5.
12. The modified phenolic novolak resin of claim 10 , wherein the mole ratio of the phenolic compound to the aliphatic diol is between about 1:0.65 and about 1:0.85.
13. The modified phenolic novolak resin of claim 10 , wherein the aliphatic diol is a pentanediol.
14. The modified phenolic novolak resin of claim 13 , wherein the pentanediol is selected from the group consisting of 2,4-pentanediol, 2,3-pentanediol, 2-methyl-2,4-pentanediol, 2,4-dimethyl-2,4-pentanediol and 2,4,4-trimethyl-2,3-pentanediol.
15. The modified phenolic novolak resin of claim 1 , wherein the aldehyde is formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, iso-butyraldehyde, n-valeraldehyde, benzaldehyde, crotonaldehyde, cinnamaldehyde, glyoxal, glutaraldehyde, furfural, phenylacetaldehyde, chloral, chloroacetaldehyde, dichloroacetaldehyde, laurylaldehyde, palmitylaldehyde, stearylaldehyde or a combination thereof.
16. The modified phenolic novolak resin of claim 1 , wherein the aldehyde is formaldehyde, the phenolic compound is resorcinol and the polyol is 2-methyl-2,4-pentanediol.
17. The modified phenolic novolak resin of claim 16 , wherein the modified phenolic novolak resin has a free resorcinol content of less than 5 weight percent.
18. The modified phenolic novolak resin of claim 16 , wherein the modified phenolic novolak resin has a softening point between about 100° C. and about 120° C.
19. A vulcanizable rubber composition, comprising (a) a rubber component selected from natural rubber, synthetic rubber or combinations thereof, (b) a methylene donor compound which generates formaldehyde upon heating, and (c) a methylene acceptor compound comprising a modified phenolic novolak resin obtained by reacting a phenolic compound with an aliphatic polyol and an aldehyde in the presence of an acid catalyst at a pH less than 7.
20. The vulcanizable rubber composition of claim 19 , wherein the mole ratio of the aldehyde to the phenolic compound is less than 0.9:1.
21. The vulcanizable rubber composition of claim 19 , wherein the pH is less than 4.
22. The vulcanizable rubber composition of claim 19 , wherein the phenolic compound is an unsubstituted resorcinol or a substituted resorcinol.
23. The vulcanizable rubber composition of claim 19 , wherein the aliphatic polyol is selected from the group consisting of 2,4-pentanediol, 2,3-pentanediol, 2-methyl-2,4-pentanediol, 2,4-dimethyl-2,4-pentanediol and 2,4,4-trimethyl-2,3-pentanediol.
24. The vulcanizable rubber composition of claim 19 , wherein the aldehyde is formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, iso-butyraldehyde, n-valeraldehyde, benzaldehyde, crotonaldehyde, cinnamaldehyde, glyoxal, glutaraldehyde, furfural, phenylacetaldehyde, chloral, chloroacetaldehyde, dichloroacetaldehyde, laurylaldehyde, palmitylaldehyde, stearylaldehyde or a combination thereof.
25. The vulcanizable rubber composition of claim 19 , wherein the methylene donor is selected from the group consisting of paraformaldehyde, hexamethylenetetramine, methylol melamines, etherified methylol melamines and esterified methylol melamines.
26. The vulcanizable rubber composition of claim 19 , wherein the vulcanizable rubber composition further comprises a vulcanizing agent, an accelerator, a reinforcing material, carbon black, a cobalt salt, stearic acid, silica, zinc oxide, a filler, a plasticizer, a wax, a processing oil, a retarder, an antiozonant or a combination thereof.
27. A process for making a modified phenolic novolak resin, comprising the step of reacting a phenolic compound with an aliphatic polyol and an aldehyde in the presence of an acid catalyst at a pH less than 7.
28. The process of claim 27 , wherein the mole ratio of the aldehyde to the phenolic compound is less than 0.9:1.
29. The process of claim 27 , wherein the pH is less than 4.
30. The process of claim 27 , wherein the acid catalyst is selected from the group consisting of benzenesulfonic acid, benzene-1,2-disulfonic acid, benzene-1,3-disulfonic acid, benzene-1,4-disulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, oxalic acid, methanesulfonic acid, 4-chlorobenzenesulfonic acid and combinations thereof.
31. The process of claim 27 , wherein the phenolic compound is represented by Formula (I):
wherein each of R 1 , R 2 , R 3 , R 4 and R 5 is independently H, hydroxyl, thiol, amido, halogen, cyano, nitro, amino, acyl, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aralkyl, alkenyl, alkynyl, alkoxy, aryloxy, acyloxy, acylamino, alkoxycarbonyl or a part of a ring where two of R 1 , R 2 , R 3 , R 4 and R 5 together from the ring with the proviso that at least two of R 1 , R 2 , R 3 , R 4 and R 5 are H.
32. The process of claim 27 , wherein the aliphatic polyol is selected from the group consisting of 2,4-pentanediol, 2,3-pentanediol, 2-methyl-2,4-pentanediol, 2,4-dimethyl-2,4-pentanediol and 2,4,4-trimethyl-2,3-pentanediol.
33. The process of claim 27 , wherein the aldehyde is formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, iso-butyraldehyde, n-valeraldehyde, benzaldehyde, crotonaldehyde, cinnamaldehyde, glyoxal, glutaraldehyde, furfural, phenylacetaldehyde, chloral, chloroacetaldehyde, dichloroacetaldehyde, laurylaldehyde, palmitylaldehyde, stearylaldehyde or a combination thereof.
34. The process of claim 27 , wherein the phenolic compound is resorcinol and the aldehyde is formaldehyde.
35. The process of claim 34 , wherein the modified phenolic novolak resin has a free resorcinol content of less than 5 weight percent.
36. The process of claim 34 , wherein the modified phenolic novolak resin has a softening point between about 100° C. and about 120° C.
37. The process of claim 27 , wherein the phenolic compound reacts with the aliphatic polyol and the aldehyde simultaneously.
38. The process of claim 37 , wherein the phenolic compound reacts with the aliphatic polyol and the aldehyde sequentially.
39. The process of claim 38 , wherein the phenolic compound reacts first with the aliphatic polyol and then with the aldehyde.
40. The process of claim 38 , wherein the phenolic compound reacts first with the aldehyde and then with the aliphatic polyol.
41. A modified phenolic novolak resin obtainable by reacting a unsubstituted or substituted resorcinol with an aliphatic polyol and an aldehyde in the presence of an acid catalyst.
42. The modified phenolic novolak resin of claim 41 , wherein the aliphatic polyol is a diol.
43. The modified phenolic novolak resin of claim 42 , wherein the mole ratio of the phenolic compound to the aliphatic diol is between about 1:0.3 and about 1:1.5.
44. The modified phenolic novolak resin of claim 42 , wherein the mole ratio of the phenolic compound to the aliphatic diol is between about 1:0.65 and about 1:0.85.
45. The modified phenolic novolak resin of claim 42 , wherein the diol is a pentanediol.
46. The modified phenolic novolak resin of claim 45 , wherein the aldehyde is formaldehyde.
47. The modified phenolic novolak resin of claim 46 , wherein the resorcinol is unsubstituted resorcinol.