Indian Patents. 200454:PROCESS FOR THE PREPARATION OF IMPROVED RESOLE-BASED PHENOL-FORMALDEHYDE COMPOSITIONS AND PRODUCTS MADE THEREFROM

Title of Invention	PROCESS FOR THE PREPARATION OF IMPROVED RESOLE-BASED PHENOL-FORMALDEHYDE COMPOSITIONS AND PRODUCTS MADE THEREFROM
Abstract	ABSTRACT A process for the preparation of Resol-based Phenol-formaldehyde composition comprising reacting Phenol and Formaldehyde in molar ratio of 1:1 9 (37% w/w solution of fonnaldehyde in water) in the presence of a base catalyst.

Full Text	The present invention relates to a process for the preparation of improved Resol-based Phenol formaldehyde compositions and products made therefrom. The Phenol-formaldehyde composition prepared according to the present invention has improved strength and integrity, which when compounded with certain blowing agents, curing agents, reinforcing agents, cross linking agents, flexibilismg agents and chain extenders as described herein, a homo-dispersed system is obtained, \\'hich when subjected to further processing with or without rigid or flexible facing substrate at elevated temperatures gradually, results into a ver\ rigid structural cellular composite which can be possibly used as structural element for the low temperature as well as high temperature applications such as automotive, projectiles, heavy duty field vehicles for military use, construction industry, aviation and space technology, ship building, nuclear technology and radio electronics and can also be used as a heat shield for the engine compartments. Such composites can withstand substantial vibration and stress and strain during use, wherein the integrity of the structural composite is maintained. BACKGROUND OF THE INVENTION Cellular products from phenol-formaldehyde composition have been known for a long time. These compositions are either Resole based or Novolac based and are synthesized from phenols, fomialdehydes and an acidic or alkaline catalyst at an elevated temperature and selectively dehyderated to the required level. However, many catalysts of the above types have been tried and polymolecular macro structures have been prepared. Such compositions could be of resolic or novolac type solid or liquid resin which is then used as base polymer and mixed and compounded with various additives e.g. solid or liquid blowing agents, reinforcing agents, cross-linking agents, particulars or fibrous fillers and the like to improve their properties. The cellular products made from the said compositions by either catalytic reaction or thermal induced reaction are cross-linked rigid substances with cellular property and have high thermal resistance. They withstand 177°C without any deterioration in mechanical properties. They also have an e.xcellent fire resistance properties. The composites are made by pouring the partially cured compounded resin between the matallic or nonmetallic substrate and further cross-linked to a rigid composite by application of heat. The conventional phenol-formaldehyde compositions have certain drawbacks which make it less efficient. The prominent drawbacks of the prior arts are mentioned here: Most of the phenol-formaldehyde resin based composites suffer form: (i) Loss of mechanical property if sandwiched between metal substrates. (ii) Decrease in bonding strength at high temperature and some times undergo thermal decomposition. (Hi) Lack of sufficient elasticity and resistance against abrasion, (iv) Composite conversion when stored at low temperature (at 15° C to 28" C) in an enclosed container or sealed poly-coated bags. (v) Insufficient dimensional stability, low compressive strength and relatively high moisture content. Once the bond between the cellular matrix and substrate is lost due to any of the above mentioned weaknesses that conventional phenol-formaldehyde composition possess, the structural part ceases to function as a composite and the integrity of the matrix is lost, resulting in a breach in the thermal barrier. The strength of the composite decreases considerably causing several fimctional failure. The main objective of the present invention is to provide an advanced method/process for the preparation of Resole-based improved phenol-formaldehyde compositions and products made therefrom, which possess improved properties than their prior arts. The new Resol-based phenol-formaldehyde compositions, prepared from present advanced process have improved mechanical strength, high bonding ability, greater elasticity and abrasion-resistance, higher dimensional stability and very low moisture content. Due to improved properties, these improved phenol-formaldehyde compositions are when compounded with certain blowing agents, curing agents, reinforcing agents, cross-lining agents, flexibilising agents and certain expenders. result into very rigid structural cellular composite which can be possibly used as structural element for the low temperature as well high temperature applications. The present advanced process of preparing impro\ed Resol-based phenol-formaldehyde composition explains the use of reactants like mixture of several tjpes of phenols and mixture of several types of aldehydes (all ingredients taken in some fixed proportions) along with the application of a mixture of alkaline catalysts at slightly elevated temperature (between 50T to 100°C). Application of such mixture of several phenols and several aldehydes and mixture of catalysts, along with the maintenance of reaction conditions is new. It is a further object of the present invration to provide composites made of improved Resol phenol-formaldehyde ccanpositions which would overcome the structural and bond failure of the conventional Resol-based phenol-formaldehyde composites and would maintain the integrity of the composites in severe stress and strain induced application areas. The details about the invention is substantially written below: Details of the advanced process of the preparation of improved Resol-based phenol-formaldehyde composition and products made therefrom: The present invention relates to a process for the perpetration of Resol-based phenol-formaldehyde composition comprising reacting phenol and formaldehyde in molar ratio of 1:1.9 (37% W/W aqueous solution of formaldehyde) in the presence of basic catalyst as herein described. According to a preferred embodiment of the invention, the molar ratio of Phenol to formaldehyde is 1:1.21. The Resol Phenol-formaldehyde condensates are prepared in the presence of base catalysts and in which the formation of phenol-alcohols is rapid but their subsequent poly-condensation is slow, and the liquid resols would normally have an average of less than two benzene rings per molecule whereas the solid resols would have the weight average molecular weight of 800 to 2000 and number average molecular weight of 400 to 1000. The solid resols of the present invention may be a mixture of more than one resol as long as the resulting resol have the required characteristics. In addition to phenol, other phenolic compounds ma>- be substituted for upto approximatelj^Jj% of phenol. Examples of other phenolic compounds include resorcinol, catacol, ortho/metal/para-cresols, xylenols, ethyl phenols, para tertiary butylphenols. nonyl phenol, cashewnut shell oils and the like. In nuclear phenolic compounds may also be used in such preparations. The most preferred composition is obtained vnth^. 1 mole of para-tert butylphenol along with equal proportion of ethyl phenol. In addition to formaldehyde aqueous solution 37% WAV) itseIf^.Qjtb6r aldehydes can also be used upto 10% of the formaldehyde. Examples of other suitable aldehydes are benzaldehyde, acetaldehyde, chloral, furfural, glyoxal and the like. However, the preferred aldehyde is the formaldehyde with a minor quantity of other aldehydes. The tenn phenolic resin, resols wouid for the purpose of this invention mean, phenol and minor proportions of phenolic compounds and formaldehyde with minor proportion of other aldehydes other than formaldehyde. The most preferred composition for this invention is 0.05 moles of furfural along with 37% w/w formaldehyd solution. The reactant phenols are aqueous solution of concentration ranging between 50 to 95% by weight concentration normally, while lower concentrations could also be i,ised. It is also possible to use 100% phenol (solid) by first charging the formaldehyde solution and applying heat and 9 gradually adding solid phenol while the agitator is on, pure phenol would then gradually dissolve. The formaldehyde reactant is also added to the reactor in a concentration between 30 to 97% w/w of formaldehyde in water, while the prefeired concentration is 37-39% w/w of formaldehyde in water. The base catalysts used for the preparation of the improved phenol-formaldehyde composition are basic compounds such as ethyl amine, diethyl amine, dimethyl ethanolamine ammonia and the like. The preferred base catalyst are ethyl amine, anmionia and the like. The catalyst concentration which has been successfully used, ranges from 0.002 moles to 0.25 moles of base per mole of phenol. The preferred range however lies between 0.04 to 0.2 moles of base per mole of phenol. In addition to this, a combination of the above mentioned catalysts may be used to obtain synergistic effect v-ithout causing any deteriorating effect on the properties of the resin composition obtained. The preferred temperature of reaction of phenol and formaldehyde is between 45°C to 120°C and the pressure being between -2 bar toJ:6_bat-The time of reaction can be varied in relation to the temperature and pressure to achieve the most optimal property of resol. The preferred state of resol begin the solid resol with very low moisture concentration e.g. between 0.1 to 0.5% of water and of desired molecular weight. It is also possible to vary the proportion of the reactants and the condition of preparation and still obtain the desired properties of the solid resol which « can be compounded and processed with the other additives to give the desired result of the end product. This has considerable advantage on the period of time the reacting components have to occupy the reactor, and therefore, has direct relationship with the commercial aspect of the manufacturing cost. The poly-condensation wouM vary based on temperature of reaction extent of polymerisation sought, concentration of the reacting components and concentration of the catalyst and the nature of the catalyst deployed. Some catalysts may required fraction of the concentration in relation to the others and still catalyse the system very effectively. Generlaly the reaction time would be between 5 hrs to 12 hrs, depending on the reaction stoichiometry and the resin characteristic of the specific application of such products. The exact time of termination of the reaction has good correlation with the melt viscosity, flow properties, gel-time, molecular wei^t and the residual water content for the combination of the molar ratios and the reaction conditions of preparation. It is preferable to render the final resin composition neutral and hence the initial base catalyst used needs to be neutralised to render the pH of the composition to 7, say betv/een 6 to 7 is preferred. This prevents the further condensation of the resin on its own and which has direct bearing on the characteristics of the compounded composite formulation. The neutralisation of the b?sic catalyst is done by the use of a mild acid such as sulphuric acid, hydrochloric acid, sulphonic acid, oxalic acid, formic acid and the like. The preferred acid being oxalic acid. In the preparation of the phenol-formaldehyde composition of the present invention, the reaction between phenol and formaldehyde along with other substituents as mentioned aforehand is carried to such an extent that when the composition is cooled below 48 ^C, is a hard solid mass that can be broken into smaller pieces or powdered with the suitable mechanical equipments such as crushers, particulators and sieving devices. The most suitable solid resole composition can be prepared by carefully choosing the correct proportions of the reactants and the catalyst and also maintaining the correct reaction conditions e.g. temperature of digestion, time of digestion, time and extent of dehydration and pressure. The properties of the phenol-formaldehyde composition prepared according to the present invention can be improved by adding several types of conventional additives such as fJexibilizers, fillers, hardening agents, blowing agents, extenders, colourants and the like. " In order to induce more elasticity to the said composition (100 pbw), 5-15 pbw of natural rubber, nitrile mbber, chloroprene rubber, styrene butadine rubber and various rubber latexs can be added Such compound/s are added during the end of the pohmerisation cycle of the phenol formaldehyde composition in the reactor to achieve a homogenous dispersion to flexibilize the composition. Alternatively such compounds can be added during the compounding operation on heated roller mill subsequent!}-. Latex rubbers, porofor, Hicar and krynac type of modified rubber compounds yield the best results. The process of preparation of the phenol formaldehyde oligomeric compounds for the manufacture of structural composites involves compounding the basic phenol formaldehyde elasticated composition and plasticizer, blowing agent, hardening agent with or \\ithout filler. The components are mixed in necessary proportions and subsequently milled several times to obtain physically inseparable homogenous mixture, producing semi cross-linked product which could be softened at temperature between TS'C to SS'C to transform the composition to a viscoelastic masticated state. > Examples of particulate or fibrous fillers which can be added to the phenol-formaldehyde composition prepared according to the present invention are exfoliated mica, copper, dust, aluminium, perlite, siesal, wood flour, wood particles, silicates, carbonates or various metals. Products manufactured fi-om such filled phenol-formaldehyde composition can withstand temperatures upto 250'C without thermal degradation for a specific period of time. Examples of blowing agents which can be added to the composition prepared according to this invention are sodium carbonate magnesium carbonate, potassium carbonate, calcium carbonate and the like which liberate carbon dioxide gas due to chemical reaction with the residual water content of the system or with the accessible fi-ee acid in the system. In addition, metal powders such as zinc, iron, aluminium, magnesium and the like have also been used to generate hydrogen gas with various acids for expansion of the matrix dependmg on the end application of the composite and their physical parameters required. The most effective gas generating system being diisocyanate of nitrourea, oxibisbenzyl-sulphonyl hydrozyl, diazominohydrazide, dinitroso pentamethylene tetramrne, hydrogen paraoxide, fluorocarbon and the like. The phenol-formaldehyde composition prepared exhibit considerable shelf life before composite conversion, when stored between 15C to 28'C in an enclosed container or sealed poly-coated bags, in contrary to tiic prior art materials, which need to be stored between 400 and 10°C, beyond which their shelf life deteriorates drastically rendering the materials non-usable. The composition prepared exhibits 'Jie bulk density of 0.18 to 0.5 gm/cm^ depending on the formulation and the filler used. The composition exhibits very good dimensional stabilit>- of 0.05% to 1.5% between temperatures ranging form 70°C to 220'C. The apparent density normally ranges between 0.18 to 3.5 gm/cm^ depending on grade of the manufacture for specific application. The compressive strength varies benveen 6 to 35 kg/'cm whereas tiie moisture uptake varies 0.1 to 25 g/m^ (24 hrs immersion) depending on the grade chosen. Since many apparently different embodiments of the present invention could be made without departing from the spirit and scope thereof, it is intended that the description of the present invention herein be interpreted as illustrative only and not limiting in any manner whatsoever. WE CLAIM: 1. A process for the preparation of Resol-based phenol-formaldehyde composition which comprises a condensation reaction between a phenol-phenolic compound mixture and a formaldehyde-aldehyde mix¬ ture in presence of a base catalyst at pH 6.5 and at the temperature of 120 degree Cen-tigrade and pressure of +6 bar where, the phenol fraction is an aqueous solution of phenol containing 0.1 mole of para— tertiarybutylphenol & 0.1 mole ethylphenol;th formaldehyde fraction is a 37% w/w aqueous formal¬dehyde solution containing 0.05 mole of furfural;the basic catalyst is 0.2 mole ammonia;and the reaction mixture maintains the molar ratio of phenol fraction to formaldehyde fraction as 111.21, for a period of 12 hours and followed by neutrali¬zation of the basic catalyst by adding a mild acid. 2. A process for the preparation of Resol-based phenol-formaldehyde composition,as claimed in claim 1,wherein the pH of the composition obtained is adjusted at about 6.5 by the use of Oxalic acid.

Full Text

The present invention relates to a process for the preparation of improved Resol-based Phenol formaldehyde compositions and products made therefrom.
The Phenol-formaldehyde composition prepared according to the present invention has improved strength and integrity, which when compounded with certain blowing agents, curing agents, reinforcing agents, cross linking agents, flexibilismg agents and chain extenders as described herein, a homo-dispersed system is obtained, \\'hich when subjected to further processing with or without rigid or flexible facing substrate at elevated temperatures gradually, results into a ver\ rigid structural cellular composite which can be possibly used as structural element for the low temperature as well as high temperature applications such as automotive, projectiles, heavy duty field vehicles for military use, construction industry, aviation and space technology, ship building, nuclear technology and radio electronics and can also be used as a heat shield for the engine compartments. Such composites can withstand substantial vibration and stress and strain during use, wherein the integrity of the structural composite is maintained.
BACKGROUND OF THE INVENTION
Cellular products from phenol-formaldehyde composition have been known for a long time. These compositions are either Resole based or

Novolac based and are synthesized from phenols, fomialdehydes and an acidic or alkaline catalyst at an elevated temperature and selectively dehyderated to the required level. However, many catalysts of the above types have been tried and polymolecular macro structures have been prepared. Such compositions could be of resolic or novolac type solid or liquid resin which is then used as base polymer and mixed and compounded with various additives e.g. solid or liquid blowing agents, reinforcing agents, cross-linking agents, particulars or fibrous fillers and the like to improve their properties. The cellular products made from the said compositions by either catalytic reaction or thermal induced reaction are cross-linked rigid substances with cellular property and have high thermal resistance. They withstand 177°C without any deterioration in mechanical properties. They also have an e.xcellent fire resistance properties. The composites are made by pouring the partially cured compounded resin between the matallic or nonmetallic substrate and further cross-linked to a rigid composite by application of heat.
The conventional phenol-formaldehyde compositions have certain drawbacks which make it less efficient. The prominent drawbacks of the prior arts are mentioned here:
Most of the phenol-formaldehyde resin based composites suffer form:

(i) Loss of mechanical property if sandwiched between metal substrates.
(ii) Decrease in bonding strength at high temperature and some times undergo thermal decomposition.
(Hi) Lack of sufficient elasticity and resistance against abrasion,
(iv) Composite conversion when stored at low temperature (at 15° C to 28" C) in an enclosed container or sealed poly-coated bags.
(v) Insufficient dimensional stability, low compressive strength and relatively high moisture content.
Once the bond between the cellular matrix and substrate is lost due to any of the above mentioned weaknesses that conventional phenol-formaldehyde composition possess, the structural part ceases to function as a composite and the integrity of the matrix is lost, resulting in a breach in the thermal barrier. The strength of the composite decreases considerably causing several fimctional failure.
The main objective of the present invention is to provide an advanced method/process for the preparation of Resole-based improved phenol-formaldehyde compositions and products made therefrom, which possess improved properties than their prior arts. The new Resol-based phenol-formaldehyde compositions, prepared from present advanced

process have improved mechanical strength, high bonding ability, greater elasticity and abrasion-resistance, higher dimensional stability and very low moisture content. Due to improved properties, these improved phenol-formaldehyde compositions are when compounded with certain blowing agents, curing agents, reinforcing agents, cross-lining agents, flexibilising agents and certain expenders. result into very rigid structural cellular composite which can be possibly used as structural element for the low temperature as well high temperature applications.
The present advanced process of preparing impro\ed Resol-based phenol-formaldehyde composition explains the use of reactants like mixture of several tjpes of phenols and mixture of several types of aldehydes (all ingredients taken in some fixed proportions) along with the application of a mixture of alkaline catalysts at slightly elevated temperature (between 50T to 100°C).
Application of such mixture of several phenols and several aldehydes and mixture of catalysts, along with the maintenance of reaction conditions is new. It is a further object of the present invration to provide composites made of improved Resol phenol-formaldehyde ccanpositions which would overcome the structural and bond failure of the conventional Resol-based phenol-formaldehyde composites and would maintain the

integrity of the composites in severe stress and strain induced application areas. The details about the invention is substantially written below:
Details of the advanced process of the preparation of improved Resol-based phenol-formaldehyde composition and products made therefrom:
The present invention relates to a process for the perpetration of Resol-based phenol-formaldehyde composition comprising reacting phenol and formaldehyde in molar ratio of 1:1.9 (37% W/W aqueous solution of formaldehyde) in the presence of basic catalyst as herein described.
According to a preferred embodiment of the invention, the molar ratio of Phenol to formaldehyde is 1:1.21.
The Resol Phenol-formaldehyde condensates are prepared in the presence of base catalysts and in which the formation of phenol-alcohols is rapid but their subsequent poly-condensation is slow, and the liquid resols would normally have an average of less than two benzene rings per molecule whereas the solid resols would have the weight average molecular weight of 800 to 2000 and number average molecular weight of 400 to 1000. The solid resols of the present invention may be a mixture of more than one resol as long as the resulting resol have the required characteristics.

In addition to phenol, other phenolic compounds ma>- be substituted for upto approximatelj^Jj% of phenol. Examples of other phenolic compounds include resorcinol, catacol, ortho/metal/para-cresols, xylenols, ethyl phenols, para tertiary butylphenols. nonyl phenol, cashewnut shell oils and the like. In nuclear phenolic compounds may also be used in such preparations. The most preferred composition is obtained vnth^. 1 mole of para-tert butylphenol along with equal proportion of ethyl phenol.
In addition to formaldehyde aqueous solution 37% WAV) itseIf^.Qjtb6r aldehydes can also be used upto 10% of the formaldehyde. Examples of other suitable aldehydes are benzaldehyde, acetaldehyde, chloral, furfural, glyoxal and the like. However, the preferred aldehyde is the formaldehyde with a minor quantity of other aldehydes. The tenn phenolic resin, resols wouid for the purpose of this invention mean, phenol and minor proportions of phenolic compounds and formaldehyde with minor proportion of other aldehydes other than formaldehyde. The most preferred composition for this invention is 0.05 moles of furfural along with 37% w/w formaldehyd
solution.
The reactant phenols are aqueous solution of concentration ranging between 50 to 95% by weight concentration normally, while lower concentrations could also be i,ised. It is also possible to use 100% phenol (solid) by first charging the formaldehyde solution and applying heat and

9
gradually adding solid phenol while the agitator is on, pure phenol would
then gradually dissolve. The formaldehyde reactant is also added to the
reactor in a concentration between 30 to 97% w/w of formaldehyde in
water, while the prefeired concentration is 37-39% w/w of formaldehyde in
water.
The base catalysts used for the preparation of the improved phenol-formaldehyde composition are basic compounds such as ethyl amine, diethyl amine, dimethyl ethanolamine ammonia and the like. The preferred base catalyst are ethyl amine, anmionia and the like.
The catalyst concentration which has been successfully used, ranges from 0.002 moles to 0.25 moles of base per mole of phenol. The preferred
range however lies between 0.04 to 0.2 moles of base per mole of phenol.
In addition to this, a combination of the above mentioned catalysts may be used to obtain synergistic effect v-ithout causing any deteriorating effect on the properties of the resin composition obtained.
The preferred temperature of reaction of phenol and formaldehyde is
between 45°C to 120°C and the pressure being between -2 bar toJ:6_bat-The time of reaction can be varied in relation to the temperature and pressure to achieve the most optimal property of resol. The preferred state of resol begin the solid resol with very low moisture concentration e.g.

between 0.1 to 0.5% of water and of desired molecular weight. It is also possible to vary the proportion of the reactants and the condition of preparation and still obtain the desired properties of the solid resol which
«
can be compounded and processed with the other additives to give the desired result of the end product.
This has considerable advantage on the period of time the reacting components have to occupy the reactor, and therefore, has direct relationship with the commercial aspect of the manufacturing cost.
The poly-condensation wouM vary based on temperature of reaction extent of polymerisation sought, concentration of the reacting components and concentration of the catalyst and the nature of the catalyst deployed. Some catalysts may required fraction of the concentration in relation to the others and still catalyse the system very effectively.
Generlaly the reaction time would be between 5 hrs to 12 hrs, depending on the reaction stoichiometry and the resin characteristic of the specific application of such products. The exact time of termination of the reaction has good correlation with the melt viscosity, flow properties, gel-time, molecular wei^t and the residual water content for the combination of the molar ratios and the reaction conditions of preparation.

It is preferable to render the final resin composition neutral and hence the initial base catalyst used needs to be neutralised to render the pH of the composition to 7, say betv/een 6 to 7 is preferred. This prevents the further condensation of the resin on its own and which has direct bearing on the characteristics of the compounded composite formulation. The neutralisation of the b?sic catalyst is done by the use of a mild acid such as sulphuric acid, hydrochloric acid, sulphonic acid, oxalic acid, formic acid and the like. The preferred acid being oxalic acid.
In the preparation of the phenol-formaldehyde composition of the present invention, the reaction between phenol and formaldehyde along with other substituents as mentioned aforehand is carried to such an extent that when the composition is cooled below 48 ^C, is a hard solid mass that can be broken into smaller pieces or powdered with the suitable mechanical equipments such as crushers, particulators and sieving devices.
The most suitable solid resole composition can be prepared by carefully choosing the correct proportions of the reactants and the catalyst and also maintaining the correct reaction conditions e.g. temperature of digestion, time of digestion, time and extent of dehydration and pressure.
The properties of the phenol-formaldehyde composition prepared according to the present invention can be improved by adding several types

of conventional additives such as fJexibilizers, fillers, hardening agents, blowing agents, extenders, colourants and the like. "
In order to induce more elasticity to the said composition (100 pbw),
5-15 pbw of natural rubber, nitrile mbber, chloroprene rubber, styrene
butadine rubber and various rubber latexs can be added Such compound/s
are added during the end of the pohmerisation cycle of the phenol
formaldehyde composition in the reactor to achieve a homogenous
dispersion to flexibilize the composition. Alternatively such compounds can
be added during the compounding operation on heated roller mill
subsequent!}-. Latex rubbers, porofor, Hicar and krynac type of modified
rubber compounds yield the best results.
The process of preparation of the phenol formaldehyde oligomeric
compounds for the manufacture of structural composites involves
compounding the basic phenol formaldehyde elasticated composition and
plasticizer, blowing agent, hardening agent with or \\ithout filler. The
components are mixed in necessary proportions and subsequently milled
several times to obtain physically inseparable homogenous mixture,
producing semi cross-linked product which could be softened at
temperature between TS'C to SS'C to transform the composition to a
viscoelastic masticated state. >

Examples of particulate or fibrous fillers which can be added to the phenol-formaldehyde composition prepared according to the present invention are exfoliated mica, copper, dust, aluminium, perlite, siesal, wood flour, wood particles, silicates, carbonates or various metals. Products manufactured fi-om such filled phenol-formaldehyde composition can withstand temperatures upto 250*'C without thermal degradation for a specific period of time.
Examples of blowing agents which can be added to the composition prepared according to this invention are sodium carbonate magnesium carbonate, potassium carbonate, calcium carbonate and the like which liberate carbon dioxide gas due to chemical reaction with the residual water content of the system or with the accessible fi-ee acid in the system. In addition, metal powders such as zinc, iron, aluminium, magnesium and the like have also been used to generate hydrogen gas with various acids for expansion of the matrix dependmg on the end application of the composite and their physical parameters required. The most effective gas generating system being diisocyanate of nitrourea, oxibisbenzyl-sulphonyl hydrozyl, diazominohydrazide, dinitroso pentamethylene tetramrne, hydrogen paraoxide, fluorocarbon and the like.
The phenol-formaldehyde composition prepared exhibit considerable shelf life before composite conversion, when stored between 15*C to 28'C

in an enclosed container or sealed poly-coated bags, in contrary to tiic prior art materials, which need to be stored between 40*0 and 10°C, beyond which their shelf life deteriorates drastically rendering the materials non-usable.
The composition prepared exhibits 'Jie bulk density of 0.18 to 0.5 gm/cm^ depending on the formulation and the filler used. The composition exhibits very good dimensional stabilit>- of 0.05% to 1.5% between temperatures ranging form 70°C to 220'C. The apparent density normally ranges between 0.18 to 3.5 gm/cm^ depending on grade of the manufacture for specific application.
The compressive strength varies benveen 6 to 35 kg/'cm whereas tiie moisture uptake varies 0.1 to 25 g/m^ (24 hrs immersion) depending on the grade chosen.
Since many apparently different embodiments of the present invention could be made without departing from the spirit and scope thereof, it is intended that the description of the present invention herein be interpreted as illustrative only and not limiting in any manner whatsoever.

WE CLAIM:
1. A process for the preparation of Resol-based
phenol-formaldehyde composition which comprises a
condensation reaction between a phenol-phenolic
compound mixture and a formaldehyde-aldehyde mix¬
ture in presence of a base catalyst at pH 6.5 and
at the temperature of 120 degree Cen-tigrade and
pressure of +6 bar where,
the phenol fraction is an aqueous solution of phenol containing 0.1 mole of para— tertiarybutylphenol & 0.1 mole ethylphenol;th* formaldehyde fraction is a 37% w/w aqueous formal¬dehyde solution containing 0.05 mole of furfural;the basic catalyst is 0.2 mole ammonia;and the reaction mixture maintains the molar ratio of phenol fraction to formaldehyde fraction as 111.21, for a period of 12 hours and followed by neutrali¬zation of the basic catalyst by adding a mild acid.
2. A process for the preparation of Resol-based
phenol-formaldehyde composition,as claimed in claim
1,wherein the pH of the composition obtained is
adjusted at about 6.5 by the use of Oxalic acid.

Documents:

1210-mas-1999 abstract dublicate.pdf

1210-mas-1999 abstract.pdf

1210-mas-1999 claims dublicate.pdf

1210-mas-1999 claims.pdf

1210-mas-1999 correspondence others.pdf

1210-mas-1999 correspondence po.pdf

1210-mas-1999 description (complete) dublicate.pdf

1210-mas-1999 description (complete).pdf

1210-mas-1999 form-1.pdf

1210-mas-1999 form-19.pdf

1210-mas-1999 form-26.pdf

1210-mas-1999 form-3.pdf

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Patent Number

200454

Indian Patent Application Number

1210/MAS/1999

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

19-May-2006

Date of Filing

21-Dec-1999

Name of Patentee

ROCON INTERNATIONAL

Applicant Address

21-A, ARCHANA ENCLAVE, ENTRENCHMENT ROAD, MARREDPALLY (EAST), SECUNDERABAD 500 026

Inventors:

#	Inventor's Name	Inventor's Address
1	ROY PRANABESH CHANDER	ROCON INTERNATIONAL, 21-A, ARCHANA ENCLAVE, ENTRENCHMENT ROAD, MARREDPALLY (EAST), SECUNDERABAD 500 026.

PCT International Classification Number

C08G008/08

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA