Method for detecting curing of the binder in a mineral fiber product
The present invention relates to a method for detecting curing and/or the local distribution of curing of the binder material, in particular for detection of anomalies of the cured binder, in a mineral fiber product. The present invention also relates to a reagent, in particular for use in such a method and the use of this reagent in the quality control of bonded mineral fiber products.
1. A method for detecting curing in a mineral fiber product which comprises mineral fibers bonded together with a cured or partly cured thermoset binder, wherein the method comprises bringing the mineral fiber product into contact with a liquid mixture comprising one or more fluorescent compounds and detecting an intensity of fluorescence and/or a pattern of fluorescence or absence of fluorescence on one or more surfaces of the mineral fiber product and/or detecting a color change on one or more surfaces of the mineral fiber product.
2. The method of claim 1 , wherein the one or more fluorescent compounds are selected from one or more of xanthenes, acridines, quinine, quinine derivatives, coumarins, aryl sulfonates.
3. The method of claim 1 , wherein the method for detecting curing comprises detection of binder distribution anomalies in the mineral fiber product.
4. The method of claim 3 , wherein the binder distribution anomalies comprise agglomeration of binder.
5. The method of claim 1 , wherein the liquid mixture comprises a fluorescent compound in a concentration of from 0.001 to 1 wt.-%.
6. The method of claim 1 , wherein the liquid mixture comprises a fluorescent compound in the form of a solution of from 0.001 to 1 wt.-% of fluorescein sodium salt in one of (1) an aqueous solution of up to 30 wt.-% of one or more C 1 to C 4 alcohols, (2) an aqueous solution of a detergent, (3) water.
7. The method of claim 6 , wherein the liquid mixture comprises from 0.01 to 1 wt.-% of fluorescein sodium salt.
8. The method of claim 6 , wherein the one or more C 1 to C 4 alcohols comprise ethanol and/or isopropanol.
9. The method of claim 1 , wherein the mineral fiber product comprises mineral fibers bonded together by a cured or partly cured thermoset binder, the non-cured binder comprising a phenol-formaldehyde based resol and optionally, a sugar component.
10. The method of claim 1 , wherein the mineral fiber product comprises mineral fibers bonded together by a cured or partly cured thermoset binder, the non-cured binder comprising (1) a water-soluble binder component obtainable by reacting at least one alkanolamine with at least one polycarboxylic acid or anhydride and, optionally, treating the reaction product with a base; (2) a sugar component; and optionally, (3) urea.
11. The method of claim 1 , wherein the mineral fiber product comprises mineral fibers bonded together by a cured or partly cured thermoset binder, the non-cured binder comprising (a) a sugar component, and one or both of (b) a polycarboxylic acid component, and (c) a component selected from amine compounds, ammonia, ammonium salts of a polycarboxylic acids.
12. The method of claim 11 , wherein the sugar component is selected from sucrose, reducing sugars, poly-carbohydrates, and mixtures thereof.
13. The method of claim 1 , wherein the mineral fiber product comprises man-made vitreous fibers selected from stone fibers, mineral fibers, slag fibers, basalt fibers, glass fibers.
14. The method of claim 1 , wherein bringing the mineral fiber product into contact with a liquid mixture comprising a fluorescent compound and detecting the intensity of fluorescence and/or the pattern of fluorescence and/or the absence of fluorescence on one or more surfaces of the mineral fiber product and/or detecting a color change on one or more surfaces of the mineral fiber product are performed immediately after curing and cooling of the binder in the mineral fiber product.
15. The method of claim 1 , wherein detecting the intensity of fluorescence and/or the pattern of fluorescence on one or ore surfaces of the mineral fiber product and/or detecting a color change on one or more surfaces of the mineral fiber product takes place by visual inspection.
16. The method of claim 1 , wherein detecting the intensity of fluorescence and/or the pattern of fluorescence on one or more surfaces of the mineral fiber product takes place under irradiation with UV light.
17. The method of claim 1 , wherein the mixture comprising one or more fluorescent compounds is brought into contact with the mineral fiber product by spraying the liquid mixture onto one or more surfaces of the mineral fiber product.
18. The method of claim 1 , wherein the mixture comprising one or more fluorescent compounds is brought into contact with one or more of the outer surfaces of the mineral fiber product.
19. The method of claim 1 , wherein the mixture comprising one or more fluorescent compounds is brought into contact with a split surface of the mineral fiber product, the one or more split surfaces resulting from cutting the mineral fiber product.
20. A reagent for the detection of curing and/or binder distribution anomalies in a mineral fiber product, wherein the reagent comprises a solution of from 0.001 to 1 wt.-% fluorescein sodium salt in (1) an aqueous solution of from 1 to 30 wt.-% of one or more C 1 to C 4 alcohols or (2) an aqueous solution comprising a detergent.