GB1566664A - Method for controlled cure of synthetic based thermosetting resin bound grouts and the like - Google Patents

Description

(54) AN IMPROVED METHOD FOR CONTROLLED CURE OF SYNTHETIC BASED THERMOSETTING RESIN BOUND GROUTS AND THE LIKE (71) We, FEB (GREAT BRITAIN) LIMITED, of Albany House, Swinton Hall Road, Swinton, Manchester, County of Lancaster, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method for curing synthetic resin based thermosetting adhesives, grouts, mortars or concrete for load bearing or load transference when used in the building and civil engineering fields.

Thermosetting, "cold curing" resins such as epoxides, polyesters, polyurethanes which are hardened by cross linking with chemical hardening agents do not achieve their full strength, resistance to creep or chemical resistance unless they are cured at an optimum temperature which is ideal for each particular formulation. Their cure is also retarded in cold weather.

The Specification of our earlier Patent No. 1,428,400 describes a method for the controlled acceleration of the setting of flexible synthetic cold curing resin bound mortar nosings for concrete paving slabs for bridges and roads to produce a load bearing wear resistant surface comprising applying a cold curing resin compound in a liquid or malleable form to recesses in the edges of adjacent concrete slabs during application of the compound by a former, inserting an electric conducting heating wire or wires and metal spacers into the compound and supplying a low voltage current to the wires to heat the compound, applying lagging above the compound and removing the lagging and former when the compound has set.

The invention comprises a method of curing synthetic resin based thermosetting adhesives, grouts, mortars or concrete comprising subjecting the composition to an even heat distribution at predetermined temperatures by passing a low voltage electric current through heating elements and a transducer permanently embedded in the composition and lagging the exposed surfaces to prevent the loss of heat or by supplying the low voltage current through a separate transducer to the elements and in which the electric current is passed through the transducer to control the temperature of the element.

The elements remain embedded in the composition after cure.

Whereas Specification No. 1,428,400 included only flexible and semi-flexible resin based mortars for use in bridge nosings and pavements, the present Application covers also the medium and high modulus resin systems for all applications where the system transmits load or is required for chemical resistance.

The invention is concerned with the precise control of the heat generated by the electrical elements through multi-wave form technique to give an optimum curing temperature or range of temperature and cure pattern thereby maximising the inherent properties of the resin composition when hardened.

The control system components may be embedded with the elements or may be recoverable or installed in a container on the exterior of the resin mass. The control system measures and acts upon the temperature of the resin adhesive, grout, mortar, flooring composition or similar product by means of a thermostat, thermistor, thermocouple, semi-conductor or the like.

The current passes through the resin mixture either on an oscillating on/off pattern, or may trickle the current through to keep the temperature at an equilibrium; or it may alter the ratio of "on" to "off" time; and may allow sharp rises and falls in the temperature to a present pattern or it may provide a suitable heat followed by a final higher burst of heat at the end of the cure period to effect a post curing or annealing process. The heating pattern may be altered to suit the particular conditions of the composition.

Electrical current is obtained from the mains or from generators on site. The control mechanism controls the temperature in relation to power consumed; the time which allows for ambient temperature; volume of material to be cured; temperature of the composition undergoing cure and allows for the exothermic or selfgenerated chemically produced heat of the compound.

The system also allows the sharing of the power supply between the various elements to reduce power consumption.

The system may employ micro-processors or similar miniaturised computer type equipment together with lights or dials to monitor the performance.

The resin may be a flexible epoxy resin, or polyester, polyurethane or similar resin of a flexible nature or it may be a polymeric resin including the aforesaid compounds with the addition of a polysulphide rubber, pine oil, pitch, bitumen, coal tar or other plasticisers and other additives such a carbon black or other conductors which may be added to increase the heat or electrical conductivity of the resin composition.

The resin based mortar, adhesive or grout is cured from the liquid or malleable condition at a temperature that will induce full cure without creating a strain or excess shrinkage in the resin. This temperature will vary according to the glass transition temperature (GTT) of the resin under cure and site requirements. The wiring circuits will vary according to the many configurations or contours that the mortar or grout must assume to follow the shape of the base materials against which it is placed and the degree of sophistication of temperature control necessary.

The invention will be described with reference to the accompanying drawing showing a wiring diagram of the apparatus.

The apparatus comprises a power source A which may be an AC or DC mains supply, battery or a motor generator feeding a variable controllers B for supplying one or more loads where two or more loads are supplied the power demand is more constant and a higher efficiency is obtained.

The controller B supplies an element or elements embedded in the compositions and g be of stainless steel wire C which may be formed as a welded mesh. galvanised The element may be arranged in series or parallel.

The elements are supplied through a transducer D which may be an integral part of the element and buried therewith in the composition or as a separate unit in contact with the work or temporarily enclosed in a pocket in the resin composition.

The transducer D may be a thermocouple, thermostat, thermistor or semi-conductor.

It has been found that the composition may comprise any of the following examples.

300 parts approximately by weight of filler-graded silica sand or similar; 100 parts by weight of liquid epoxy resin; 50 parts by weight of reactive liqud polyamide.

It has been found that an epoxy grout similar to the above will have its setting time at 100C reduced from three days to one day when cured in the manner described. A further benefit will be improved physical and chemical resistance properties due to the high degree of cross linking achieved. Similar benefits are derived with a wide range of thermo-setting resins, the following of which is typical: 200 parts approximately by weight of graded silica sand; 100 parts by weight of liquid polyester resin; 1-5 parts by weight of benzoyl peroxide.

WHAT WE CLAIM IS: - 1. A method of curing synthetic resin based thermosetting adhesives, grouts, mortars ar concrete comprising subjecting the composition to an even heat distribution at predetermined temperatures by passing a low voltage electric current through heating elements and a transducer permanently embedded in the composition and lagging the exposed surfaces to prevent the loss of heat or by supplying the low voltage current through a separate transducer to the elements and in which the electric current is passed through the transducer to control the temperature of the elements.

2. A method of curing synthetic resin according to claim 1 substantially as hereinbefore described.

3. Apparatus when used for curing the synthetic resin composition as claimed in Claim 1 substantially as described with reference to the accompanying drawing.

4. A synthetic resin comPosition when cured by the method of claim 1 substantially as hereinbefore described.

J. OWDEN O'BRIEN & SON,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   temperature to a present pattern or it may provide a suitable heat followed by a final higher burst of heat at the end of the cure period to effect a post curing or annealing process. The heating pattern may be altered to suit the particular conditions of the composition.

   Electrical current is obtained from the mains or from generators on site. The control mechanism controls the temperature in relation to power consumed; the time which allows for ambient temperature; volume of material to be cured; temperature of the composition undergoing cure and allows for the exothermic or selfgenerated chemically produced heat of the compound.

   The system also allows the sharing of the power supply between the various elements to reduce power consumption.

   The system may employ micro-processors or similar miniaturised computer type equipment together with lights or dials to monitor the performance.

   The resin may be a flexible epoxy resin, or polyester, polyurethane or similar resin of a flexible nature or it may be a polymeric resin including the aforesaid compounds with the addition of a polysulphide rubber, pine oil, pitch, bitumen, coal tar or other plasticisers and other additives such a carbon black or other conductors which may be added to increase the heat or electrical conductivity of the resin composition.

   The resin based mortar, adhesive or grout is cured from the liquid or malleable condition at a temperature that will induce full cure without creating a strain or excess shrinkage in the resin. This temperature will vary according to the glass transition temperature (GTT) of the resin under cure and site requirements. The wiring circuits will vary according to the many configurations or contours that the mortar or grout must assume to follow the shape of the base materials against which it is placed and the degree of sophistication of temperature control necessary.

   The invention will be described with reference to the accompanying drawing showing a wiring diagram of the apparatus.

   The apparatus comprises a power source A which may be an AC or DC mains supply, battery or a motor generator feeding a variable controllers B for supplying one or more loads where two or more loads are supplied the power demand is more constant and a higher efficiency is obtained.

   The controller B supplies an element or elements embedded in the compositions and g be of stainless steel wire C which may be formed as a welded mesh. galvanised The element may be arranged in series or parallel.

   The elements are supplied through a transducer D which may be an integral part of the element and buried therewith in the composition or as a separate unit in contact with the work or temporarily enclosed in a pocket in the resin composition.

   The transducer D may be a thermocouple, thermostat, thermistor or semi-conductor.

   It has been found that the composition may comprise any of the following examples.

   300 parts approximately by weight of filler-graded silica sand or similar;

   100 parts by weight of liquid epoxy resin;

   50 parts by weight of reactive liqud polyamide.

   It has been found that an epoxy grout similar to the above will have its setting time at 100C reduced from three days to one day when cured in the manner described. A further benefit will be improved physical and chemical resistance properties due to the high degree of cross linking achieved. Similar benefits are derived with a wide range of thermo-setting resins, the following of which is typical:

   200 parts approximately by weight of graded silica sand;

   100 parts by weight of liquid polyester resin; 1-5 parts by weight of benzoyl peroxide.

   WHAT WE CLAIM IS: - 1. A method of curing synthetic resin based thermosetting adhesives, grouts, mortars ar concrete comprising subjecting the composition to an even heat distribution at predetermined temperatures by passing a low voltage electric current through heating elements and a transducer permanently embedded in the composition and lagging the exposed surfaces to prevent the loss of heat or by supplying the low voltage current through a separate transducer to the elements and in which the electric current is passed through the transducer to control the temperature of the elements.
2. 2. A method of curing synthetic resin according to claim 1 substantially as hereinbefore described.
3. 3. Apparatus when used for curing the synthetic resin composition as claimed in Claim 1 substantially as described with reference to the accompanying drawing.
4. 4. A synthetic resin comPosition when cured by the method of claim 1 substantially as hereinbefore described.

   J. OWDEN O'BRIEN & SON,