DE1694703C3 - Manufacture of synthetic resin bonded grinding wheels - Google Patents

Description

In Sehleifniiuelmassen for grinding tools, z. B. Grinding wheels were previously made of silicates or K;) utschuk;) Jten, but mainly ceramic Binder used. With the increasing development of the synthetic resin, however, grinding tools are also included a synthetic resin binder made in large quantity so that these grinding tools are now in They are used to a similar extent as those with a ceramic binder. Even with grinding machines The glue used up to now is increasingly being used in the form of curses and tufted papers Replaced synthetic resin binder.

Epoxy resins are used as synthetic resin binders. Polyvinyl alcohol and especially phenol formaldehyde resin are used. Synthetic resin-bonded abrasive compounds have the advantage that they have high strength and can be aged at low temperatures during their manufacture. However, when the abrasive (wet a large amount of an inorganic abrasive, it is difficult to enemies the inorganic abrasive with an organic binder: in addition, the mechanical properties 4p abrasive material are influenced by the properties of the Klebcflächen.

It is known to improve the bond between the inorganic abrasive and the abrasive Organic binders are used to provide the abrasives with a silicone resin coating. This cnt- »There is a sufficiently strong bond between the silicone resin and the organic binder, but it is The bond between the silicone resin and the organic abrasive was not sufficiently strong because Tier often used electro-corundum and the increasingly used sintered corundum AbOi exists, so that due to the differences between the Al'Oi and the binding group in the silicone resin existing —O —Si-Gruppc with regard to the ionitchen Character and ionic radius no sufficient rake bond can be achieved.

Subject invention is a method for producing resin-bonded abrasive body by providing abrasive particles with a silicone resin coating and the particles are then reacted with a resin to IO

20th

30th

35

45

55

processed into a molded body, characterized in that that the abrasive particles are corundum particles used, on which a silicone coating is melted before coating with the silicone resin or save shark.

In this way it can also be used between silicon resin and abrasives create a sufficiently strong bond.

The one with the invention educates special \ orieil consists in the fact that a grinding wheel is hcrgesielli λ λ. the a higher strength than the previously known masses and a higher resistance to water and Owns heat. This once creates the dragging effect improved, on the other hand, this abrasive element in the In contrast to the previously known synthetic resin-bound "" Abrasives - can also be used for wet grinding. Educate them through the tiimdiing Advantages will be particularly evident with Schleilmchein and sandpaper. in which synthetic resin is used as a binder and which in increasing matt be discontinued, have a beneficial effect.

The inventive production of an abrasive body is shown below with reference to an example: els explained.

A slurry consisting of electro corundum (No. 3b) was coated with a finely powdered mixture of bO ",., Feldspar. 10% limestone and 3O ¹ Vn clay.

For this purpose, the Elektrokoriind was used existing abrasives immersed in a slurry of the coating composition specified above. dried and calcined at about 1200 ° C.

The abrasive powder coated in this way Electro-corundum was made with γ-aminopropyltriäiho \\ silane treated The mixture of the abrasive obtained in this way with the readjust ^! listed resins In the specified proportions, an abrasive mixture resulted in:

Treated as stated above
Abrasives made from electro corundum 90

Liquid phenolic formaldehyde resin (resole) 2

Powdered phenol formaldehyde resin
(Novolak) ⁸

The mixture was agitated in the usual manner and placed in a mold so that a molded body was formed a bulk weight of 2.30 g / cm 'was obtained. This shaped body was then aged in the usual way. The abrasive article obtained in this way was compared to abrasive articles also produced in the manner described above were, however, using a conventional abrasive made from untreated electrical corundum. one Electro-corundum abrasive. which had only been coated with the silicone resin. or an abrasive made of electro corundum. which had only been provided with a ceramic coating. The results are given below:

Flexural strength kg / cm ² water resistant wedge
kg / cm ²

Degradation
%

Heat resistance kg / cm '

Untreated

Treated with γ-aminopropyltriethoxysilane
Ceramic coating
Treatment according to the invention

290 72 75 100 310 100 b8 110 300 100 67 150 400 400 0 200

To determine the resistance to water, the resistance of a grinding wheel that had been immersed in warm water at 40 ° C. for 10 days was measured. To determine the heat resistance, the strength of a sliding body was measured at 250 ° C.

It can be seen from the results given above that those prepared according to the invention Abrasive media have excellent strength and water-resistant wedge. They also stand out with an excellent grinding effect.

In the context of the invention, as abrasives Llektmkoruiid and .Sinterkorund of the usual kind ν w ill be used.

According to the original procedure, the Abrasives by melting them or adding them to the surface coated with a silicate, which mainly atjs SiO: considered.

The Sinieren perauir used for covering is on the collection of the silica used depending and lying! between 100 and 1400 C ".

Claims (1)

Claim: Process for producing synthetic resin-bonded abrasive articles by using abrasive particles a silicone resin and then the particles with a synthetic resin to form a molded article processed, characterized in that corundum particles are used as the abrasive particles, which are then coated with has melted or sintered a silica coating on the silicone resin.