The use of vinyl and vinylidene chloride latexes in the manufacture of asbestos cardboard

Abstract

The need to create an inexpensive paper-like material based on mineral fibers is due to the protection of thermal insulation of pipelines. Materials used: mineral fibers ‒ asbestos grades M-4-20; binder ‒ vinyl- and vinylidene-chloride latexes VKHVD-65, DVKHB-70; coagulant ‒ aluminum sulfate. Method used: production of samples of asbestos cardboard from a fibrous composition in a TAPPI sheet‒filling machine, wt. h.: 100 asbestos fiber; 5‒60 latex; 3‒10 coagulant. For each composition of the fibrous composition, 10 samples were cast for testing. The properties of the material are characterized by physical‒mechanical parameters: breaking length (L, m); tear resistance (E, mN) and penetration (Po, kPa); absorbency during unilateral wetting (G, g/m2) and capillary (B, mm); degree of sizing (C, c/mm). Results: the strength of castings depends on the nature, binder and coagulant content: for latexes DVKHB-70/ VKHVD-65 ‒ Lmax = (504‒662)/(384‒417) with a significance level of α = 0.05 in the composition, wt.h.: 5‒20 latex; 3‒6 coagulant; Lmin = 206/(132‒168) with α = 0.05 in composition, wt.h.: 25‒60 latex; 7‒10 coagulant; Po(max) = (14‒15)/20 kPa with α = 0.05 at a content of 10/(10‒20) wt.h. latex. Samples with VKHVD-65 are hydrophilic: Gmax / Bmax = (2 ‒3)/(4‒5) with α = 0.05. With an increase in the content of DVKHB-70, the values of G decrease from 1‒3 to zero with α = 0.05; B ≈ 0 for any content of DVKHB-70. The results mean: in theory, the physical and mechanical properties of asbestos cardboard are determined by the film‒forming properties of binders ‒ synthetic latexes; in practice, the compositions of fibrous suspensions for obtaining a protective material with high consumer properties are determined. Conclusion: a key advantage for readers is the practical confirmation of the possibility of creating new composite materials with ingredients of various natures ‒ mineral and organic. The range of latexes with other monomers suitable for the production of asbestos cardboard remains unresolved.