The addition of limited amount of urea to resin to the resin solution just before use, either directly or in a hardener is a well-known and often recommended way of reducing the smell of formaldehyde. But it is not easy to determine quantitatively what type of product this contributes, whether resin or insoluble methylene urea compound; it depends on the molar ratio, the pH on addition, the rate at which the pH falls during curing, and the temperature.
It will be noticed that the term “water tolerant” is used. This expression, for reasons that are given later, is often more accurate and therefore is preferable to “water-solubility.” Here, the term is used to apply to the behaviour of the uncured resin, and should not be confused with “water-resistance,” a term that is applied to the cured adhesive.
More on Chemicals Composition
Popular Posts
-
The chemical compositions of the materials are also established by the material specifications for each type or grade of material. The eleme...
-
Double tape for mounting object on the wall or to stick steel on other steel, see here before you decide to choose the right double tape: 3M... -
Find some double tape product that is sold in the market. Compare the price of many double sided tape trade mark that sold in online shop i...
-
Performance of urea-formaldehyde (UF) resin can be improved by modified low molar ratio UF resins were developed to improve water resistan...
-
Novolak are made under acide conditions, when the formation of methylol compounds is slow, whereas the conversion of methylol compound to d...
No comments:
Post a Comment