RU2387105C2 - Method of resistive material production - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention may be used to manufacture of resistive type heaters, is aimed at provision of possibility to produce non-flammable resistive material with even heat field and wide range of specific resistance from R_sp=10 Ohm/m² to R_sp=10000 Ohm/m². Resistive material is prepared by means of single application of current-conducting composition on base, containing binder, carbon and solvent, binder used is represented by organic-silicate composition, carbon in the form of colloid graphite, solvent used is water plus modifying additives, taken in the following ratio, wt %: organic-silicate composition 10-50, colloid graphite 8-20, modifying additive 0-1, water - the rest, then dried at the temperature of 150°C. Current-conducting composition is prepared by means of components mixing in a certain ratio, depending on required parametres of resisitve material, base used to apply current-conducting composition is represented by paper.

EFFECT: simplified manufacturing of resistive material, possibility to manufacture elements with wide range of resistance, elimination of resistive materials fire risk, higher evenness of heat field.

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Description

The invention relates to electrical engineering and can be used in the manufacture of resistive heaters.

Known resistive heaters based on acrylic resin and graphite, which have a small stable active resistance when exposed to high temperatures and moisture (French Patent No. 2241856, CL H01C 7/02, 1975).

Known heating fabric, consisting of a glass base as a substrate, a heating layer based on polyvinyl chloride and graphite, a layer of polyvinyl chloride that protects the electrically conductive material from moisture (US Patent No. 3876968, CL 338-211, 1975). The manufacture of such a heater requires special equipment (rollers, calendars).

A known method of manufacturing a resistive material, which consists in the fact that a conductive material with a given resistance is obtained by applying a conductive layer to a glass fabric and then distributing it using rolls (RF Patent 2079209).

Disadvantages - the complexity of manufacturing, requires special equipment.

The closest technical solution to the claimed prototype is a method of manufacturing a resistive element for a polymer electric heater (copyright certificate 1793564, class H05B 3/14), in which a conductive binder is prepared from a modified phenol-formaldehyde resin, elemental carbon and solvent, and once impregnated with a reinforcing fabric, which is used as a conductive polymer fabric based on shell-core filaments. The shell is made of vinyl chloride filled with elemental carbon, and the core is made of nylon. The surface resistance of a tissue square of 100 × 100 mm is from 1 kΩ to 1.5 kΩ.

The disadvantages of this invention, as well as the above, are: the complexity of manufacturing, the requirement for special equipment, the inability to manufacture elements with a wide range of resistance, the fire hazard of finished products, insufficient uniformity of the resistive material and, as a consequence, the unevenness of the thermal field.

The objective of the invention is to remedy these disadvantages of known analogues: simplifying the method of manufacturing resistive material for flat electric heaters, the possibility of manufacturing resistive materials with a wide resistance range, eliminating the fire hazard of resistive materials, increasing the uniformity of the thermal field.

The technical result is achieved by the fact that for the manufacture of a resistive material a conductive composition is prepared, including carbon, a binder and a solvent, and once impregnated with a base. In this case, an organosilicate composition is used as a binder, carbon in the form of colloidal graphite, water as a solvent, and modifying additives are additionally introduced. The conductive composition is prepared by mixing all the components in a certain ratio depending on the required parameters of the resistive material, and paper is used as the basis.

For the manufacture of resistive material, the components of the binder are taken in the ratio, wt.%: Organosilicate composition 10-50, colloidal graphite 8-20, modifying additive 0-1, water - the rest is thoroughly mixed, applied to roll paper using an impregnating machine, dried applied layer at a temperature of 150 ° C. After that, the resistive material is cut into sheets of the required size, busbars are attached and coated with electrical insulating material.

Example 1 preparation of resistive material:

For the manufacture of resistive material take 10 wt.% Organosilicate composition, 15 wt.% Colloidal graphite, 0.5 wt.% Modifier, 74.5 wt.% Water. Everything is thoroughly mixed, applied to paper on an impregnation machine, followed by drying at a temperature of 150 ° C. The result is a non-combustible, uniform in resistance resistive material with a specific resistance of 100 Ohm / m ² .

Examples 2-7 are carried out analogously to example 1, but with different ratios of a binder, graphite, modifier and solvent.

The results are shown in the table.

Name The ratio of components, wt.% one 2 3 four 5 6 7 Binder 10 thirty fifty thirty thirty thirty thirty Colloidal graphite fifteen fifteen fifteen 8 twenty fifteen 5 Modifier 0.5 0.5 0.5 0.5 0.5 0 one Water 74.5 54.5 34.5 61.5 50,5 55 64 Specific resistance one hundred 90 80 550 10 95 10,000 resistive material, Ohm / m ²

From these examples it can be seen that a different ratio of components allows to obtain a resistive material of different resistivity, while the resistive material becomes completely non-combustible.

The impregnation mechanism and the properties of the electrically conductive composition, which depend on the ratio of the components, make it possible to obtain resistive material with a specific resistivity and thermal radiation uniform over the entire area. By changing the speed of impregnation, the ratio of the components of the conductive composition applied to the paper, it is possible to achieve a wide range of resistivity of the resistive material: Rsp = 10 ÷ 10,000 Ohm / m ² . This allows you to create electric heaters based on resistive materials of any shape, for any voltage, any power, and as a result, expand the scope of electric heaters.

The proposed resistive material as part of a building thermoelectric mat product was tested by the AIL of electronic equipment and electrical equipment of the Federal State Institution “Novosibirsk TsSM” (test report No. IL10-018 of January 29, 2008 for compliance with GOST 12.2.007.9-93).

As tests have shown, resistive material can be used as a heating element for the production of thermoelectric construction mats.

These thermoelectric mats have been manufactured since February 2008 in Novosibirsk by the LLC LVK Plant enterprise and are used throughout the Russian Federation to warm concrete, soil, etc.

Claims (1)

A method of manufacturing a resistive material in which a conductive composition of a binder, carbon and solvent is prepared and once impregnated with a base, characterized in that an organosilicate composition is used as a binder, carbon is used in the form of colloidal graphite, water is used as a solvent, and modifying additives are additionally introduced. while the conductive composition is prepared by mixing the components taken in the ratio, wt.%: organosilicate composition 10 ÷ 50, colloidal graphite 8 ÷ 20, modify adding additive 0 ÷ 1, water - the rest; dried at a temperature of 150 ° C with subsequent application to the base, which is used as paper.