Curatives for phenolic novolacs
AssigneeBorden, Inc.
InventorArthur Harry Gerber
Life of this patent
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Abstract
A binder composition of a phenolic novolac resin and a (lower) alkoxylated triazine-formaldehyde resin curing agent is disclosed. The triazine resins have sufficient carbon atoms in the alkoxy groups so as to provide a curing agent having a water solubility of less than 15%. The binder cures at high temperatures so as to provide improved flow and prolonged workability to the composition. The compositions are useful in refractory applications having a need for high temperature curing agents such as for maintenance and repair within refractory vessels by gunning/spraying, manufacture of electrodes by the Soderberg method, and for use in blast furnace tap holes.
Claims48
A refractory composition comprising a mixture of:
- A. a particulate refractory aggregate;
- B. a phenolic novolac resin in an amount which on curing binds the aggregate;
- and
- C. a triazine resin having a water solubility of less than 15% by weight at 24.degree. C. and a degree of polymerization of about 1 to 2.5 wherein the quantity of triazine resin is about 3 to about 20% based on the weight of the novolac, said triazine resin selected from the group consisting of a (lower) alkoxylated melamine-formaldehyde resin having a formaldehyde:melamine ratio of at least about 4.3 and at least about 4.3 alkoxymethyl groups per triazine ring.
A refractory composition comprising a particulate refractory aggregate and a resin binder system, said resin binder system comprising a mixture of a particulate phenolic novolac resin in an amount for binding the aggregate on curing and a hardener in an amount for hardening the novolac, said hardener comprising:
- a (lower) alkoxylated triazine-formaldehyde resin prepared by reacting melamine or benzoguanamine with formaldehyde at a ratio of at least 4.3 moles of formaldehyde for each mole of melamine to produce a triazine-formaldehyde resin and subsequently (lower) alkoxylating the triazine-formaldehyde resin to produce a (lower) alkoxylated triazine-formaldehyde resin having from about 1.0 to 2.5 triazine rings per molecule and wherein the total number of carbon atoms of the alkoxy groups provides a water solubility of less than about 10% by weight at 24.degree. C. for the (lower) alkoxylated triazine-formaldehyde resin, wherein sealed mode differential scanning calorimetry for a sample essentially composed of 90 parts of the novolac and 10 parts, by weight, of the alkoxylated resin has at least 50% of its caloric exotherm at a temperature of at least 200.degree. C., wherein the quantity of the triazine is from about 3 to 20% based on the weight of the novolac, and wherein the triazine resin has at least about 4.3 alkoxymethyl groups per triazine ring.
A method for maintenance and repair of a refractory surface which comprises delivering a refractory composition to a refractory structure having a surface temperature of at least about 250.degree. F., wherein the refractory composition comprises (a) a mixture of a particulate refractory aggregate, about 3% to 30% of phenolic novolac resin based on the weight of the refractory, and from about 3% to 20% of a hardener based on the weight of the novolac with (b) from about 3% to 25% by weight of water based on the composition, and wherein the hardener is a triazine resin having a degree of polymerization of about 1 to 2.5 selected from the group consisting of a (lower) alkoxylated melamine-formaldehyde resin, wherein the total number of carbon atoms in such alkoxy groups provides a water solubility of less than about 10% by weight at 24.degree. C. of the triazine resin, the alkoxylated melamine-formaldehyde resin having a formaldehyde:melamine ratio of at least about 4.3 and at least about 4.3 alkoxymethyl groups per triazine ring.
A method for the preparation of a shaped refractory which comprises thermoforming at a temperature above 150.degree. C. a composition comprising a mixture of:
- A. a particulate aggregate;
- B. a phenolic novolac resin in an amount which on curing binds the refractory;
- and
- C. a triazine resin having a degree of polymerization of about 1 to 2.5 wherein the quantity of triazine resin is in an amount for curing the novolac, said triazine resin selected from the group consisting of a (lower) alkoxylated melamine-formaldehyde resin, wherein the number of carbon atoms in such alkoxy groups provides the triazine resin with a water solubility at 24.degree. C. of less than 15% by weight, wherein sealed mode differential scanning calorimetry for a sample essentially composed of 90 parts of the novolac and 10 parts, by weight, of the alkoxylated resin has at least 50% of its caloric exotherm at a temperature of at least 200.degree. C., the alkoxylated melamine-formaldehyde resin having a formaldehyde:melamine ratio of at least about 4.3 and at least about 4.3 alkoxymethyl groups per triazine ring.
A method for improving the mechanical properties of a refractory article which comprises impregnating such article at an elevated temperature with a solution comprising a mixture of:
- A. a phenolic novolac;
- B. a triazine resin having a degree of polymerization of about 1 to 2.5 wherein the quantity of triazine resin is in an amount for curing the novolac from about 3 to 20% based on the weight of the novolac, said triazine resin selected from the group consisting of a (lower) alkoxylated melamine-formaldehyde resin wherein the number of alkoxy groups and the number of carbon atoms in such alkoxy groups provides the triazine resin with a water solubility at 24.degree. C. of less than 15% by weight, wherein sealed mode differential scanning calorimetry for a sample essentially composed of 90 parts of the novolac and 10 parts, by weight, of the alkoxylated resin has at least 50% of its caloric exotherm at a temperature of at least 200.degree. C., the alkoxylated melamine-formaldehyde resin having a formaldehyde:melamine ratio of at least about 4.3 and at least about 4.3 alkoxymethyl groups per triazine ring;
- and
- C. optionally an organic solvent.
A method for preparing a blast furnace tap hole plug which comprises introducing a tapping rod and a tap hole composition into the tap hole wherein said tap hole composition comprises:
- A. a particulate refractory;
- B. a curable solution of a phenolic novolac resin in an amount which on curing binds the refractory;
- and
- C. a triazine resin having a degree of polymerization of about 1 to 2.5 wherein the quantity of triazine resin is about 3 to about 20% based on the weight of the novolac, said triazine resin selected from the group consisting of a (lower) alkoxylated melamine-formaldehyde resin wherein the number of alkoxy groups and the number of carbon atoms in such alkoxy groups provides the triazine resin with a water solubility at 24.degree. C. of less than 15% by weight;
- and subsequently thermally curing the novolac resin, wherein sealed mode differential scanning calorimetry for a sample essentially composed of 90 parts of the novolac and 10 parts, by weight, of the alkoxylated resin has at least 50% of its caloric exotherm at a temperature of at least 200.degree. C., the alkoxylated melamine-formaldehyde resin having a formaldehyde:melamine ratio of at least about 4.3 and at least about 4.3 alkoxymethyl groups per triazine ring.
A refractory composition comprising a mixture of:
- A. a particulate refractory aggregate;
- B. a phenolic novolac resin in an amount which on curing binds the aggregate;
- and
- C. a triazine resin having a water solubility of less than 15% by weight at 24.degree. C. and a degree of polymerization of about 1 to 2.5, wherein the quantity of triazine resin is about 3 to about 20% based on the weight of the novolac, said triazine resin selected from the group consisting of a (lower) alkoxylated melamine-formaldehyde resin having a formaldehyde:melamine ratio of at least about 4, wherein the triazine resin comprises a mixture of triazine compounds having a Formula I:
- ##STR4## wherein each of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 is independently a member of the group consisting of hydrogen, methylol and (lower) alkoxymethyl having a formula (A--O--CH.sub.2)-- wherein group A is alkyl of 1 to 6 carbon atoms;
- and n is 0 or 1;
- wherein when n is 0 about 75% to 95% of the R.sub.1-6 groups are (lower) alkoxymethyl, and at about a 75% to 89% level of the alkoxymethyl groups the average such alkoxymethyl group has at least 2 carbon atoms in the group A and at about the 90% to 95% level of the alkoxymethyl groups, the average such alkoxymethyl group has at least 1 carbon atom in the group A;
- wherein when n is 1, about 50% to 95% of the R 1-6 groups are alkoxymethyl and at about a 50% to 75% level of the alkoxymethyl groups the average such alkoxymethyl group has at least 2 carbon atoms in the group A and at about the 76% to 95% level of the alkoxymethyl groups, the average such alkoxymethyl group has at least 1 carbon atom in the group A.
A refractory composition comprising a mixture of:
- A. a particulate refractory aggregate;
- B. a phenolic novolac resin in an amount which on curing binds the aggregate;
- and
- C. a triazine resin having a water solubility of less than 15% by weight at 24.degree. C. and a degree of polymerization of about 1 to 2.5 wherein the quantity of triazine resin is about 3 to about 20% based on the weight of the novolac, said triazine resin selected from the group consisting of a (lower) alkoxylated melamine-formaldehyde resin having a formaldehyde:melamine ratio of at least about 4, wherein the triazine resin comprises a triazine compound having a single triazine ring having at least about 4 alkoxymethyl groups.
Dependencies are inferred from the claim text.