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US 8,778,495 B2Granted
Phenol-formaldehyde novolac resin having low concentration of free phenol
AssigneeGerogia-Pacific Chemicals LLC
InventorsRichard A. Rediger, Edward Lucas
Life of this patent
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Abstract
A phenol-formaldehyde novolac resin having a low concentration of free phenol prepared by distilling residual phenol from a molten novolac resin and replacing at least a portion of the phenol with a solvent having a volatility equal to or less than phenol. Such modified novolac resins are suitable for the production of resin coated molding sands for shell molding and sand cores, as well as for the production of resin coated proppants for use in oil and gas recovery operations.
Claims20
A coated particle, comprising:
- a particle selected from the group consisting of sand, silica, ceramic, and bauxite;
- and
- a coating comprising:
- a solid phenol-formaldehyde novolac resin containing less than 0.5 wt % free phenol;
- and
- about 1 wt % to about 8 wt % of a non-phenolic solvent consisting of a mixture of dibasic esters, wherein the solid phenol-formaldehyde novolac resin with the non-phenolic solvent has a melt viscosity of 1,260 cps at 150° C. to less than 5,000 cps at 150° C., wherein the mixture of dibasic esters comprises about 20 wt % to about 35 wt % dimethyl adipate, about 65 wt % to about 80 wt % dimethyl glutarate, and up to 3 wt % dimethyl succinate, wherein the solid phenol-formaldehyde novolac resin has a melting point of 77° C. to 93° C., and wherein the coating contains no other non-phenolic solvent.
3 more elements
A method comprising:
- depositing a coating at least partially onto a particle selected from the group consisting of sand, silica, ceramic, and bauxite, wherein the coating comprises:
- a solid phenol-formaldehyde novolac resin containing less than 0.5 wt % free phenol;
- and
- about 1 wt % to about 8 wt % of a non-phenolic solvent consisting of a mixture of dibasic esters, wherein the solid phenol-formaldehyde novolac resin with the non-phenolic solvent has a melt viscosity of 1,260 cps at 150° C. to less than 5,000 cps at 150° C., wherein the mixture of dibasic esters comprises about 20 wt % to about 35 wt % dimethyl adipate, about 65 wt % to about 80 wt % dimethyl glutarate, and up to 3 wt % dimethyl succinate, wherein the solid phenol-formaldehyde novolac resin has a melting point of 77° C. to 93° C., and wherein the coating contains no other non-phenolic solvent.
1 more element
A coated proppant, comprising:
- a particle selected from the group consisting of silica, ceramic, and bauxite;
- and
- a coating disposed at least partially on the particle, wherein the coating comprises:
- a solid phenol-formaldehyde novolac resin containing less than 0.5 wt % free phenol;
- and
- about 1 wt % to about 8 wt % of a non-phenolic solvent consisting of a mixture of dibasic esters, wherein the mixture of dibasic esters comprises about 20 wt % to about 35 wt % dimethyl adipate, about 65 wt % to about 80 wt % dimethyl glutarate, and up to 3 wt % dimethyl succinate, wherein the solid phenol-formaldehyde novolac resin with the non-phenolic solvent has a melt viscosity of 1,260 cps at 150° C. to less than 5,000 cps at 150° C., wherein the solid phenol-formaldehyde novolac resin has a melting point of 77° C. to 93° C., and wherein the coating contains no other non-phenolic solvent.
3 more elements
Dependencies are inferred from the claim text.