Title of Invention	"A FORMULATION FOR THE MODIFICATION OF ACID CURE PHENOLIC RESIN"
Abstract	This invention relates to a formulation for the modification of acid cure phenoic resole resin based moulding sand for extension of its bench life from 7-3 minutes to 20-15 minutes at varying temperature from 31-34°C by adding an alcohol such as propylene glycol to the resin.

Full Text

FIELD OF INVENTION This invention relates to a formulation for the modification of acid cure phenolic resole resin. This invention relates to a formulation for the modification of acid cure phenolic resole resin based moulding sand used for the manufacture of sand moulds/cores. BACKGROUND OF THE INVENTION At present phenolic resole resin (resole type) along with para-toluene sulphonic acid (catalyst) is used as a binder for the preparation of the composition for moulding sand for the manufacture of moulds/cores in the Foundry Industries. The above composition is a fast setting system and has a very short bench life varying from 3 to 7 minutes in summer, particularly when the atmosphere is dry and ambient temperature is above 30°C. This period is not enough to complete the total process of preparation of moulds/cores involving the various types of activities such as application of facing sand, fixing of chills and Kalminex sleeves/Kal Board with wooden riser and refractory gating system etc. As a result, the moulds/cores prepared have the following defects due to week bonding between the sand particles:- 1. Multiple parting lines. 2. Sand mould surface becomes friable 3. Mould surface hardness is lower than the prescribed value (50). Due to above defects cropping in, the quality of the overall mould becomes poor leading to high rate of rejection/rework. OBJECTS OF THE INVENTION It is therefore an object of this invention to propose a formulation for the modification of acid cure phenolic resole resin which provides the operator sufficient time for the preparation of sand moulds/cores. Another object of this invention is to propose a formulation for the modification of acid cure phenolic resole resin, which enables adjustment of the bench life of the moulding sand to suit environment conditions of temperature and humidity. Yet another object of this invention is to propose a formulation for the modification of acid cure phenolic resole resin, which enables reduction in the viscosity of the resin, thereby facilitating the mixing of sand and binder. Still another object of this invention is to propose a formulation for the modification of acid cure phenolic resole resin, which reduces the inherent brittleness of phenolic resole resin. These and other objects of the invention will be apparent from the ensuing description. At the outset of the description which follows, it is to be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only an exemplary embodiment and the teaching of the invention is not intended to be taken restrictively. DESCRIPTION OF THE INVENTION The invention relates to a formulation for modification of acid cure phenolic resole resin based moulding sand and a process for the preparation thereof. The formulation of the present invention comprises the bench-life extender which is an alcohol such as polyethylene glycol/propylene glycol and phenolic resole resin. The glycol, which is the bench life extender, is added to the resin and stirred thoroughly, to obtain the formulation at a given condition of ambient temperature of humidity. The formulation consisting of 10-25 parts of bench life extender and 100 parts of phenolic resole resin, provides reasonable bench life of 15-20 minutes and strip time/strength to the moulding sand to suit ambient condition of temperature and humidity. The composition of the modified phenolic resole resin based moulding sand used in sand moulds, cores, comprise the 100 parts by weight of sand, the formulation of the present invention 1.6% by weight of the sand and a catalyst such as Paratoluene sulphonic acid in quantity of 35-40% of the weight of the formulation. The formulation of the present invention achieves an improvement of bench life of the order of 20-15 minutes at temperature 31-34°C without sacrificing the end requirements. It is used for the preparation of sand moulds/cores for casting of various items of weight up to 5 tons of metal. The formulation has been successfully implemented at steel foundry of BHEL for manufacture of a number of moulds/cores, which have not been found to get damaged or distorted during stripping/handling. This process has resulted in the increased productivity and over all improvement in quality of the sand mould/cores. This invention relates to a formulation for the modification of acid cure phenoic resole resin for extension of bench life (setting time) from 7-3 minutes to 20-15 minutes at varying temperature from 31-34°C of acid cure phenolic resole resin based moulding sand used for preparation of sand moulds/cores in a foundry industry by adding 10-25 parts by weight of an alcohol such as propylene glycol, polyethylene glycol etc. to 100 parts by weight of acid cure phenolic resole resin in order to obtain overall improvement in the quality of sand moulds/cores. WE CLAIM; 1. A formulation for the modification of acid cure phenoic resole resin based moulding sand for extension of its bench life from 7-3 minutes to 20-15 minutes at varying temperature from 31-34°C by adding an alcohol such as propylene glycol to the resin. 2. A formulation consisting essentially of, in admixture: a) Acid cure phenolic resole resin used as a binder. b) Paratoluene Sulphonic Acid used as a catalyst. c) An alcohol used as bench life extender to retard ambient temperature hardening of a mixture of said formulation and sand. 3. The formulation as claimed in claim 1 wherein said phenolic resole resin has a viscosity of 250cP at 25°C, non-volatile matter of at least 72% and pH in the range 5-6. 4. The formulation as claimed in claim 1 wherein the said Paratoluene Sulphonic Acid is an aqueous solution having normality of at least 4N. 5. The formulation as claimed in claim 1 wherein the said alcohol selected from the group consisting of Polyethylene glycol, Propylene glycol etc is Propylene glycol and wherein its amount varies from 10- 25 parts per 100 parts of phenolic resole resin depending upon the ambient temperature and humidity. 6. The modification of the pheonlic resole resin involves addition of 10- 25 parts of an alcohol to 100 parts by weight of acid cure phenolic resole resin. 7. A formulation for the modification of acid cure phenoic resole resin substantially as herein described and illustrated.

Documents:

959-DEL-2003-1-Correspondence Others-(08-11-2011)..pdf

959-del-2003-abstract.pdf

959-del-2003-claims.pdf

959-DEL-2003-Correspondence Others-(08-11-2011).pdf

959-del-2003-correspondence-others.pdf

959-del-2003-correspondence-po.pdf

959-del-2003-description (complete).pdf

959-del-2003-form-1.pdf

959-del-2003-form-19.pdf

959-del-2003-form-2.pdf

959-del-2003-form-3.pdf

959-del-2003-form-5.pdf

959-del-2003-gpa.pdf

959-del-2003-petition-138.pdf