G. S. Abashidze, Institute of Mining Mechanics, Tbilisi, Georgia; N. M. Chikhradze, Mining Institute, Tbilisi, Georgia
The capron- modificated phenol-formaldehyde resin is used as the new type adhesive composition and basalt fabric- as extender. The cold hardening of resin is realized not by traditional hardening agent- benzene sulphonic acid but by means of the metal salts of variable valency (FeCl3 × 6H2O; SnCl2 ·2H2O). The basalt fibre used for the fabric producing has the following chemical composition: SiO2 – 47,4; Al2O3 – 15,3; CaO – 10,5 ; Na2O – 4,2 ; MgO – 8,8 ; Fe2O3 – 12,1 ; MnO – 0,7 ; SO3 – 0,25; TiO2 - 0,7 The obtained material in comparison with the analogous composition based on phenol- formaldehyde resin has both less contraction and less corrosion activity relating to the products contacting with it. An initial degree of polycondesation of adhesive resin is 60- 65% and then, at the exposure under natural conditions, increases up to 90%. In connection with it, during the first year, the strength at first increases considerably: at extension by 18%, at bending by 52%. The modulus of composition elasticity increases by 83% too. By the end of year, the increment of these indexes in comparison with initial ones is 5 and 60%, respectively. The values of indexes of tested samples are the following: the limit of strength (at extension)- 99,8 MPa, at bending – 38,0 MPa, the modulus of elasticity – 5600 MPa. As a result of the composition holding in 5% hydrochloric acid at moderate temperature (40°C) the strength limit decreases by 20 and 26% and at the holding in 10% hydrochloric acid- at 18 and 12% during the extension and bending, respectively. By the action of 10% hydrochloric acid at the same temperature the strength decrease accounts 40% and 30% and by the action of 30% solution of H2SO4 – 55% and 45% during the extension and bending, respectively.
Summary: The obtained material in comparison with the analogous composition based on phenol- formaldehyde resin has both less contraction and less corrosion activity relating to the products contacting with it.