CS269034B1 - Admixture into lubrications for glass fibres' surface - Google Patents

Abstract

The solution describes the use of sodium hexametaphosphate as an additive to lubricants, to inhibit cement corrosion of glass fibers, when used as cement reinforcement.

Description

The present invention relates to a glass fiber cement corrosion inhibitor for surface treatment of fibers.

Increasing the corrosion resistance of glass fibers in the cement environment is a fundamental problem of their successful application to the production of glass-fiber composites. For these reasons, various additives, so-called inhibitors, of glass fiber corrosion are constantly in the spotlight.

Aromatic compounds with hydroxyl groups (Nos. 178 822 and 212 211), mainly pyrogallol and trihydroxybenzoic acid derivatives, have found important applications as corrosion inhibitors. Their disadvantage is that the handling of 3 lubricants based on them results in the skin coloring of workers. The use of terpolymers such as styrene-acrylethylene acrylic is known (cf. Aut. No. 249,961), but the alkalinity of the treated fibers does not allow their use in the production of glass-cement compositions used in high humidity environments.

The above-mentioned drawbacks are substantially eliminated by the solution according to the invention. SUMMARY OF THE INVENTION The use of sodium hexametaphosphate as an additive to inhibit the cement corrosion of glass fibers into glass fiber surface lubricants

This use is based on the empirical finding that sodium hexametaphosphate reacts in situ after depositing fibers having a surface-fixed sodium hexametaphosphate in cement with calcium hydroxide to form a coating that increases the resistance of glass fibers to cement corrosion.

The advantage of the solution according to the invention lies mainly in the fact that sodium hexametaphosphate is a commercially available raw material, practically harmless to health, to the solution according to the invention. aut. osv. No. 249 961 increases the resistance to cement corrosion by up to 20%, as assessed by the SIC method, i.e. by determining the tensile strength of fibers centered in a cement matrix in water at 80 ° C for 96 h.

The invention is illustrated by way of example.

Example

Glass made of 58.3 wt. % silica, 11.4 wt. zirconium dioxide, 8.6% by weight calcium oxide, 14.3% by weight sodium oxide and 7.4% by weight titanium dioxide. Glass fibers with an average thickness of 13 µm with 200 fibers in the strand were treated with an aqueous composition containing 10% by weight of a styrene-ethylhexyl acrylate-acrylic acid terpolymer dispersion (48% by weight), 2.5% by weight of carboxylated amidoprypoltriethoxysilane (50% by weight) and 1% by weight of a quaternized oxyethylated stearylamine based lubricant and wetting agent (dry matter 50% by weight). The glass fibers treated with the base lubricant have an alkalinity resistance, expressed in the tensile strength of the fibers, the center of which has been deposited in the cement matrix in water at 80 ° C for 96 h, 365 MPa. κ sodium hexametaphosphate at a different concentration was added to this basic lubrication, and the treated fibers were evaluated using the basic lubrication. using an inhibitor in an amount of 1% by weight, the tensile strength is 390 MPa, 5% by weight 432 MPa and 10% by weight 445 MPa.

Claims (1)

Use of sodium hexametaphosphate as an additive to inhibit cement corrosion of glass fibers into a lubricant to treat the surface of glass fibers.