Hoechst Aktiengesellschaft

Eckart Teschner

Wolfgang Hesse

Richard Sattelmeyer

Jurgen Ritz

Richard Settelmeyer

Harald Riedel

This invention relates to a method for the manufacture of an abrasive material by means of a synthetic binder based on a mixture of phenolic resins. The phenolic resins employed have a great stability in storage, its curing times are at most equal to but preferably shorter than those commonly used, therefore higher production speeds or substantially smaller drying installations for the same production speed may be used. The binder contains only small quantities of free formaldehyde, phenol and especially formaldehyde are released in substantially reduced quantities to the environment even when the binder is heated to elevated temperatures, including temperatures above the processing temperature. The release of these substances is also considerably reduced when the abrasive material is subsequently used. The synthetic binder is based on an aqueous mixture of phenolic resins and optionally other additives wherein the mixture of phenolic resins comprises (I) at least one phenolic-resol and (II) at least one co-condensate of at least one monohydric phenol and at least one polyhydric phenol with formaldehyde. The molar ratio of the quantities of formaldehyde used to the sum of phenols in component (II) is within the range of from 0.6:1 to 1.5:1. An abrasive material prepared by means of said method is a further object of this invention.

Synthetic resin binders and their use for the manufacture of abrasives

Process for the manufacture of an abrasive material comprising at least two binder layers formed from at least one aqueous resol I prepared from a monohydric phenol and formaldehyde (molar ratio of phenol to formaldehyde 1:(1.1 to 2.5)) by the application of a first binder layer onto a carrier material, scattering abrasive particles thereon, drying the covering layer in a horizontal dryer to displacement resistance and thereafter cooling with an air stream, application of a second binding agent layer and in similar manner to the first step, drying to imprint resistance and thereafter cooling, whereby the heating and cooling are each effected by means of an air stream through slit nozzles arranged transversely to the direction of travel of the abrasive web and, after loosely forming the product into a roll, final curing is effected on the product in roll form, the coated carrier material being conveyed at speeds above 5 m/min through the dryers which have well defined and individually controllable heating and cooling zones and the air stream has a velocity of 5 to 200 m/s at the nozzle outlets and a temperature of 20 to 300.degree. C., the air being extracted through adjacent extraction nozzles.

Process for the manufacture of abrasives

A synthetic resin binder comprising an aqueous mixture of phenolic resins and optionally other additives wherein the mixture of phenolic resins comprises (I) at least one phenol-resol and (II) at least one co-condensate of at least one monohydric phenol and at least one polyhydric phenol with formaldehyde and wherein in component (II) the molar ratio of the quantities of formaldehyde used to the sum of phenols is within the range of from 0.6:1 to 1.5:1, a method for the manufacture of an abrasive by means of said synthetic resin binder and the abrasives itself.

An abrasive material and process for manufacturing the same. The process comprises: (i) applying a basic binder layer to a flexible support; (ii) scathering abrasive particles onto the basic binder layer; (iii) drying and subsequently cooling the resultant product; (iv) applying a second binder layer as a sizer to the cooled product of step (iii); (v) drying and cooling the sizer; (vi) loosely rolling up the product of step (v); and (vii) curing and subsequently cooling the product of step (vi) by passing a heating or cooling air stream substantially axially through the rolled-up product. The basic and second binder layers each comprise an aqueous mixture of (A) at least one predominantly ortho-structural resol having a molar ratio of phenolic component to formaldehyde of from 1:(1.1 to 2.5), and (B) at least one polyvinyl alcohol in an amount of from 5 to 30% by weight based on the weight of solid phenolic resin.

Abrasive material and process for manufacturing the same

A process for preparing abrasives which comprises coating a fibrous substrate with a binder comprising a hardenable resin and subsequently curing the binder coat by electron irradiation. The radiation dose may have an energy of from 175,000 to 1,000,000 eV and a dose of from 0.5 to 30 Mrad. An abrasive which is obtained by the process and which is water resistant.

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Hunstetten-Limbach, Germany

Eckart Teschner