Foaming composition for water tank of solar water heater

Abstract

The invention discloses a foaming composition for a water tank of a solar water heater, which is characterized by comprising the following main raw materials: a polyether foaming agent, sodium bicarbonate, chitosan and hollow glass beads. The improved polyether rigid foam composition can be used for reducing the phenomena that after being sprayed from a glossy jar and formed, a polyurethane material has high contractibility, the heat preservation effect of the water tank of the solar water heater is influenced and the water tank is deformed, bulged and barred, or even cracked.

Description

technical field [0001] The invention relates to a thermal insulation material for a water tank of a solar water heater, in particular to a composition mainly composed of a polyether foaming agent. Background technique [0002] Due to the vigorous promotion of environmental protection and energy saving in the world, solar water heaters have become the main source of domestic hot water, and my country's solar water heaters have become the world's first user and producer of solar water heaters. As we all know, for solar water heaters, especially vacuum tube solar water heaters, polyurethane hard foam is mainly used as the insulation material of the water tank at present, because polyurethane hard foam has a low thermal conductivity and is easy to form, but one of the main defects of polyurethane hard foam is shrinkage after molding (The foam volume after the molding reaction is smaller than the maximum volume during the molding process), the existence of molding shrinkage often...

AI Technical Summary

Problems solved by technology

As we all know, for solar water heaters, especially vacuum tube solar water heaters, polyurethane hard foam is mainly used as the insulation material of the water tank at present, because polyurethane hard foam has a low thermal conductivity and is easy to form, but one of the main defects of polyurethane hard foam is shrinkage after molding (The foam volume after the molding reaction is smaller than the maximum volume during the molding process), the existence of molding shrinkage often makes the final volume of the foam body smaller than the volume of the cavity filled, and the peeling phenomenon between the foam and the shell occurs; and because the polyurethane is hard The reason for the surface tension when the foam is foaming is that the connection between the cell walls of the bubbles is not good, which reduces the pore size and connectivity. After the reaction molding, the foam disappears and collapses, causing the water tank to deform, bulge and even crack, that is, the sun Water heater manufacturers often say "peeling", "shelling", "drawing out a backbone" and other phenomena

Seriously affect the appearance, heat preservation effect and even service life of the product

Therefore, in most applications, some use thickened polyurethane hard foam layer, and some use methods such as increasing the filling foam density and molding to solve the problem, but thickening the polyurethane hard foam layer increases the external volume of the water tank and increases the cost. The use of molding also increases the difficulty of manufacturing