CS248442B1 - Abrasive layer binder on base of phenol resin - Google Patents

Abstract

The phenolic binder is added 1 to 20% iron (III) chloride which accelerates condensation and curing reactions and thereby the drying and curing process substantially shortens or can be dried lower temperatures are used. Compared to other substances with similar effect in chloride ferric during the batch processing of the binder to increase temperature or consistency nor the negative effects on functional properties grinding layers of finished products.

Description

The present invention relates to a phenolic resin binder for the purpose of producing an abrasive layer of abrasive papers, cloths and combinations.

Of the known and commercially available binders for this purpose, the phenolic resin appears to be the best for functional, processing and cost reasons. It is also used cleanly in various modifications consisting in the addition of fillers, plasticizers or substances to prevent the oxidation of ground surfaces or otherwise affecting the grinding process.

The production of abrasive papers, canvases and combinations takes place in two stages. In the first one, a layer of liquid phenolic resin solution (a skin adhesive solution may be used) is applied to a strip of paper or textile substrate with a width of 800 to 1400 mm, into which oriented corundum or silicium carbide grinding grains are poured in a special device. Drying follows. In the second phase, a so-called overcoating is performed, again with a phenolic resin solution, dried and cured at 120 ° C. The resin is dried only to the state of resitol, when it is still plastic while still hot, but is no longer sticky to the touch. At this stage, the preform is rolled into rolls, followed by curing at 120 ° C to a state of resit. Drying should be carried out very slowly, as there is a risk of pores and blisters causing loss of adhesion of the abrasive layer to the substrate. Dryers for this purpose must therefore be built as hinged, very large (several thousand m ^) and heated up to 120 ° C.

The disadvantages of the above-mentioned state are substantially eliminated by the phenolic resin-based abrasive layer binder according to the invention, which comprises ferric chloride in an amount of 1 to 20% by weight. parts per 100 parts by weight of resin.

phenolic resin binder with ferric chloride addition significantly reduces drying time and heat requirements. While drying of the abrasive layer with phenolic binder takes at 60 ° C min. 90 minutes with an uncertain result, after the addition of ferric chloride, this layer is completely dry after 20 minutes and the resin is in the state of resitol. Also, further curing to the resit state is reduced from the original 4 hours at 120 ° C to 1.5 hours. To a large extent, the formation of blisters and pores is abrasive

Ml MS

- 2-layer · No negative impact on grinding performance or durability of finished products was found.

The stability of the aqueous solution of phenolic resins in admixture with iron (III) chloride is dependent on the ability of the resin to absorb water and can be substantially increased by the addition of 5 to 20% ethylene glycol or diethylene glycol. Both substances also have a beneficial effect on the functional properties of the abrasive layer.

Application example

The following binder is prepared for the overcoat layer of the No. 80 abrasive grinding paper:

1) phenolic resins ............. 100 wt. parts kaolin .......................... 20 wt. parts ferric chloride ................ 5 wt. parts ................................ 30 masses · parts

2) phenolic resin 100% by weight. parts of diathylene glycol ................. 15 wt. parts of ferric chloride ................ 10 wt. parts water ......................... 20 wt. parts

The ferric chloride is used in the form of 50 < > aqueous solution.

Claims (1)

SUBJECT OF THE INVENTION Phenolic resin-based abrasive layer binder for the manufacture of abrasive papers, canvases and combinations, characterized in that it contains ferric chloride in an amount of 1 to 20 wt. parts per 100 parts by weight of resin.