DE102020002640A1 - Resin-bonded abrasive tool - Google Patents

Abstract

The present invention relates generally to a resin-bonded abrasive tool that is obtainable by a process in which one or more Si compounds from the group comprising silanes, siloxanes, silazanes and silicone resins are added to the usual mixture of abrasive particles, organic binder and filler.

Description

The present invention relates generally to a method for producing a resin-bonded abrasive tool in which one or more Si compounds from the group comprising silanes, siloxanes, silazanes and silicone resins are added to the usual mixture of abrasive grain, organic binder and filler and this mixture is added after shaping and Compaction is cured for a longer period of time at an elevated temperature. Abrasive tools obtainable with the method are also the subject of the invention.

Resin-bonded abrasive tools of various types are generally known from the prior art. In addition to cutting, grinding and grinding disks, some with a fabric insert for reinforcement, there are also carrier-bound abrasive tools such as grinding pads, abrasive paper, grinding segments and the like, as well as grinding stones.

These abrasive tools are all made from a mixture of abrasive grain, organic binder and fillers by filling the mixture into a mold or applying it to a carrier and then compacting it and hardening it at an elevated temperature.

From the DE 696 09 709 T2 discloses an abrasive article having a bond system comprising a polysiloxane, the polysiloxane serving as a lubricant. Furthermore, the disclosure is essentially directed to abrasives in which the abrasive bodies contained are fiber-bonded or filament-bonded and the polysiloxane does not necessarily have to be present in the same filament with the abrasive body. Bonded abrasives are only mentioned in general and in passing.

the WO 93/24272 discloses in particular cut-off wheels as abrasives in which polysiloxanes are used as a friction-increasing component, in particular poly (dimethyl) siloxanes.

An increased bond of abrasive particles within the bond matrix or the bond system is not disclosed at any point in the cited prior art.

Although such abrasive tools have been known for years and are constantly being further developed, there is a need for improvement in the state of the art, since certain disadvantages could not be overcome or only insufficiently so far and it is also desirable to improve the cutting or grinding performance of these tools.

The problems in the prior art that have not been adequately solved so far include the aging of the abrasive tools solely during storage, which is caused by the absorption of water, in particular due to the absorption of water vapor or atmospheric humidity. In the worst case, the tools only have a shelf life of a few years and can then no longer be used even if they have not yet been used. Even if the effect of water absorption is not that disadvantageous and the tools can still be used in principle, a power loss of up to 30% in cutting performance can be expected.

Another problem is the integration of the abrasive grain into the matrix, i.e. the strength with which the abrasive grain is bound to the matrix. To improve this integration, it is known to coat the abrasive grain or the abrasive grains or the abrasive grain _{mixture with metal oxides, in particular Fe 2} O ₃ , or to silanize the abrasive grain with adhesion promoters before the abrasive grain is introduced into the mixture for producing the abrasive tool. Colloidal silica is also used for this purpose.

Although improvements have already been achieved in this way, there is still a need for improved abrasive tools with a longer shelf life and better cutting performance, in particular there is a need for abrasive tools with an improved G-factor, the quotient of the separated area and the area loss of the abrasive tool.

The object of the invention is therefore to provide a method for producing improved abrasive tools which overcome at least some of the disadvantages known from the prior art and which can be produced inexpensively.

The present object is achieved by a method according to the attached claim 1 and by a resin-bonded abrasive tool according to claim 10. Advantageous embodiments of the invention are the subject matter of the directly or indirectly referenced dependent claims.

1. a) Mischen von Schleifkorn, organischem Bindemittel und Füllstoff,
2. b) nachfolgend Zugeben von einer oder mehreren Si-Verbindungen aus der Gruppe umfassend Silane, Siloxane, Silazane und Silikonharze und Vermischen mit der in Schritt a) hergestellten Rohmischung, gefolgt von einem
3. c) Einfüllen in eine Form, Verdichten der Mischung und abschließendes
4. d) Härten des in Schritt c) hergestellten Formgegenstands bei einer Temperatur im Bereich von 100 °C bis 300 °C für eine Dauer von 10 bis 70 Stunden zum Erhalt eines Abrasivwerkzeugs.

The method according to the invention for producing an abrasive tool comprises the following method steps in the specified sequence:

1. a) Mixing abrasive grain, organic binder and filler,
2. b) subsequently adding one or more Si compounds from the group comprising silanes, siloxanes, silazanes and silicone resins and mixing with the raw mixture prepared in step a), followed by one
3. c) pouring into a mold, compacting the mixture and finally
4. d) curing the molded article produced in step c) at a temperature in the range from 100 ° C. to 300 ° C. for a period of from 10 to 70 hours to obtain an abrasive tool.

1. a) Mischen von organischem Bindemittel und Füllstoff,
2. b) nachfolgend Zugeben von einer oder mehreren Si-Verbindungen aus der Gruppe umfassend Silane, Siloxane, Silazane und Silikonharze und Vermischen mit der in Schritt a) hergestellten Rohmischung, gefolgt von einer
3. c) Zugabe von Schleikorn und Vermischen mit der in Schritt b) hergestellten Mischung, dann
4. d) Einfüllen in eine Form, Verdichten der Mischung und abschließendes
5. e) Härten des in Schritt d) hergestellten Formgegenstands bei einer Temperatur im Bereich von 100 °C bis 300 °C für eine Dauer von 10 bis 70 Stunden zum Erhalt des Abrasivwerkzeugs.

In an independent and alternative embodiment, the method for producing an abrasive tool has the following sequence of method steps:

1. a) Mixing organic binder and filler,
2. b) subsequently adding one or more Si compounds from the group comprising silanes, siloxanes, silazanes and silicone resins and mixing with the raw mixture prepared in step a), followed by a
3. c) adding the grain and mixing with the mixture prepared in step b), then
4. d) pouring into a mold, compacting the mixture and finally
5. e) curing the molded article produced in step d) at a temperature in the range from 100 ° C. to 300 ° C. for a period of from 10 to 70 hours to obtain the abrasive tool.

Regardless of the process variant selected, in an advantageous further development, if only monomeric silanes with exclusively aliphatic substituents on the Si atom with a chain length of C ₁ to C ₅ are used as one or more Si compounds, an additional catalyst is added to accelerate the Conversion of the Si compound in an amount of 0.1 to 10% by weight of the total amount of Si compound.

It should be understood that the catalyst to accelerate the conversion of the Si compound or the Si compounds can in principle also be added in an independent embodiment, that is to say also in the case of silanes other than the mentioned monomeric silanes with exclusively aliphatic substituents on the Si atom with a chain length of C ₁ to C ₅ .

It is essential to the invention that one or more Si compounds from the group comprising silanes, siloxanes, silazanes and silicone resins are added to a mixture of abrasive grain, organic binder and filler known per se from the prior art and then processed further to appropriate abrasive tools, with hardening at the specified temperature and for the specified duration is made responsible for an extremely strong, reactive binding of abrasive grain to the binder.

The addition of the one or more Si compounds made it possible to improve the strength of the abrasive grain in the matrix of organic binder and filler in an extremely surprising manner. In this context, it is assumed that this is based on a chemical reaction between the abrasive grain and the Si compound (s), which leads to the formation of cloud-shaped structures that can be clearly seen in the scanning electron microscope, in which the transition from the abrasive grain to the matrix disappears and is no longer recognizable is. In the present case, it is therefore assumed that the abrasive grain is chemically bound into the matrix according to the invention, while the prior art only assumes an adhesive binding.

To achieve this effect and the resulting structural difference from the prior art, in a preferred embodiment of the present invention, it is sufficient if the one or more Si compounds are added to the mixture in an amount between 0.1 and 25% by weight of the total mass of abrasive grain, organic binder and filler.

The one or more Si compounds from the group consisting of silanes, siloxanes, silazanes and silicone resins are preferably selected from one or more of the alkylsilanes, arylsilanes, fluoroalkylsilanes, epoxysilanes, acetoxysilanes, silicic acid esters, alkylsiloxanes, cycloalkylsiloxanes, polysiloxanes, alkylsilazanes, alkyldisilazanes , Methylphenyl silicone resins, methoxy functional methylpolysiloxane resins, and silanol functional methylphenyl silicone resins, and mixtures thereof.

If more than one Si compound is used in the context of the present invention, these are usually first mixed with one another before they are added to the mixture of abrasive grain, organic binder and filler. This at least promotes a uniform distribution of the Si compounds.

Alternatively, there is the possibility of first mixing one or more Si compounds with organic binder and filler and then adding abrasive grain.

In the investigations into the present invention, it was also surprisingly found that an addition of the one or more Si compounds in dissolved or colloidally dissolved form and in fine distribution, in particular by spraying or slow dropping or pouring, has a positive effect on the bonding of the abrasive grain to the Has binder. When adding bulk, this effect cannot be reproduced, for example, by prolonged or more intensive mixing.

A further improvement in the binding of the abrasive grain to the binder can be achieved by mixing after the addition of the one or more Si compounds with the introduction of high shear forces, preferably by maintaining a high number of revolutions during mixing.

If a catalyst is used, it should preferably be added in an amount of 0.1 to 5% by weight of Si compound or Si compounds used. The catalyst is preferably an organotitanium catalyst, particularly preferably a Ti-isopropoxide catalyst, or a cobalt catalyst, in particular co-acetate or co-acetylacetonate. In principle, however, other catalysts can also be used. These are, in particular, organometallic catalysts, with organometallic catalysts containing Ti, Zr, Co, Cu, Zn, Sn, Fe, Mn, Mg, Al, or B being preferred.

Also particularly surprising is the fact that as abrasive grain, where the term “abrasive grain” in the context of the present invention is to be understood both in the singular and in the plural and also includes mixtures of abrasive grains of different sizes and / or different types, without restriction all Types of abrasive grains customary in the present field can be used, such as, for example, molten or sintered corundum, i.e. Al ₂ O ₃ , zirconium corundum, sintered, microcrystalline sol-gel-α-aluminum oxide, cubic boron nitride or diamond, silicon carbide, silicon nitride and boron carbide. The proportion of abrasive grain in the mixture is generally between 30 and 93% by weight, preferably 55 to 70% by weight.

In the context of the present invention, binders that are relevant in the present field and known in the art are used as binders and include, for example, thermosetting resin such as epoxy resin, phenolic resin, polyamide resin, polyurethane resin, urethane acrylate or rubber, or mixtures thereof, both liquid and Powder resins can also be used. In the case of phenolic resins, for example, resoles as liquid resins and novolaks as powder resins. The binders are contained in the mixture in a proportion of 5 to 40% by weight, preferably in a proportion of 25 to 37% by weight.

As is customary in the prior art, a polymerization accelerator or peroxide catalyst can also be added to the binder in a proportion of 0.5 to 5 wt.

The organic binder used in the context of the present invention can generally be used in liquid form, in solid form or in a mixture of liquid and solid form with the abrasive grain and the filler, regardless of the chosen configuration of the method.

The fillers are also the same as those known from the prior art and have the same functions. These are contained in the mixture to an extent of 5 to 20% by weight. Here you can choose from a variety of fillers, such as cryolite, pyrite or iron oxide.

According to this process, resin-bonded abrasive tools are available which have improved cutting performance, lower wear and / or improved aging behavior.

These abrasive tools obtainable by the process according to the invention are particularly preferably cutting, grinding or grinding disks.

The present invention is initially explained in general by the following description and then again on the basis of selected exemplary embodiments. As already mentioned, the order in which the individual components are added is conditional and can be varied in accordance with the two process alternatives disclosed herein. The procedure described below was chosen solely for the reason of a certain standardization and comparability, in particular with the comparative example, because in this way all the effects that occur can be assigned exclusively to the inventive modification of the known manufacturing process.

First of all, a raw material for the production of cutting or grinding wheels or sample segments is produced. For this purpose, corundum is first mixed with organic binding agents and fillers in an agitator. If necessary, a wetting agent is then added to the mass and the mixture is stirred again. Finally, the mass is sieved.

This raw mass can be used directly or stored before further processing. If the raw mass is not processed further directly, it is sieved again before further processing to avoid clumping.

The raw mass is then modified according to the invention, i.e. immediately after its production or after intermediate storage and repeated sieving, by adding one or more Si compounds after the addition of wetting agent and stirring for 2 to 10 minutes, also when the one or more Si compounds Compounds after storage of the raw material is or will be added. Normally there are no larger agglomerates, but to be on the safe side it is sieved again as described for the production of the raw material.

The raw mass modified in this way can be further processed immediately or stored again temporarily. If intermediate storage takes place, the modified raw mass is sieved again before further processing.

In some cases, it has surprisingly been found that intermediate storage obviously leads to a tire of the mixture, which is reflected in a better, i.e. stronger connection of the abrasive grain.

It has surprisingly been found that when mixing and when adding Si compounds, two factors have a particular influence on the end result, i.e. the resin-bonded abrasive tool.

On the one hand, the abrasive grain is activated more strongly during mixing with the application of high shear forces, i.e. for example when mixing at a high number of revolutions and is better integrated in the subsequent implementation and there is a more even distribution in the mixture, which also results in more intensive and homogeneous crosslinking results.

On the other hand, when introducing the Si compound or the Si compounds, fine atomization is advantageous for a more uniform distribution of the same and a more homogeneous crosslinking. This is therefore preferably done by spraying the dissolved Si compound with a spray mist that is as fine as possible, by sprinkling it or by slowly adding it. Under no circumstances should the Si compound be added all at once as a batch. Introduction by spraying is preferred, particularly preferably with a fine spray mist.

A particular and at least surprisingly advantageous advantage of the addition of Si compounds according to the invention is that the compression in a mold, compression molding, leads to a denser packing in the abrasive tool and is attributable to the friction-reducing properties of the Si compounds. This also promotes and strengthens a firm integration of the abrasive grain into the matrix.

Another advantage, which is also ascribed to the Si compounds, is that the resin-bonded abrasive tools obtained as a result are hydrophobic and resistant to humidity and steam. They can be stored at least longer and without special measures, such as individual packaging and the like, under normal ambient conditions and show at least a greatly slowed down aging or decrease in performance. Surprisingly, it has actually been found that the abrasive tools according to the invention generally even experience an improvement in performance through aging.

Finally, it should also be mentioned that during compression molding, part of the Si compound used emerges on the surface of the pressed tool and collects. This is commonly referred to as oiling out and unexpectedly results in easier demoldability and separability before and after the heat treatment.

This heat treatment or hardening process is generally carried out at a temperature in the range from 100 ° C. to 300 ° C., depending on the binder used, in particular between 120 ° C. and 200 ° C. or between 250 ° C. and 300 ° C., for a period of 10 hours carried out for up to 70 hours, in particular for a period of 12 hours to 48 hours, the specified process parameters being of particular importance as compliance with them requires sufficient reaction of the Si compound or Si compounds used with the binder on the one hand and with the abrasive grain on the other hand enables.

At lower temperatures and / or a shorter time for curing, there is no sufficient reactive binding of abrasive grain to binder and the strength of the binding of abrasive grain to binder is not significantly increased.

The following examples give compositions for a raw material according to the prior art as a comparative example and as a blank sample and for raw materials modified according to the invention.

A mixture of equal mass fractions of silanized corundum is used as the grinding body in all of the compositions given below. Examples 1 to 3 each contain only one Si compound, while Examples 4 to 8 contain two Si compounds. In Examples 4 and 5, the Si compounds were each added as a mixture. All percentages are given as percent by weight,% by weight:

Comparative example (unmodified raw material)

Corundum (silanized Al ₂ O ₃ ) 65.44% 5000 g Phenolic resin 18.96% Cryolite 15.60%

example 1

Corundum (Al ₂ O ₃ ) 65.44% 5000 g Phenolic resin 18.96% Cryolite 15.10% 1163 g Baysilone polydimethylsiloxane M 50 0.50% 38 g

Example 2

Corundum (Al ₂ O ₃ ) 65.44% 5000 g Phenolic resin 18.96% Cryolite 15.10% Polydimethylsiloxane H-terminated (average M _n ∼ 580) 0.50% 38 g

Example 3

Corundum (Al ₂ O ₃ ) 65.44% 5000 g Phenolic resin 18.96% Cryolite 15.10% Polydimethylsiloxane hydroxy-terminated (Korasilon Oil R 0.5) 0.25% 19 g

Example 4

Corundum (Al ₂ O ₃ ) 65.69% 5000 g Phenolic resin 18.96% Cryolite 15.10% Baysilone polydimethylsiloxane M 50 0.45% 34 g Polydimethylsiloxane H-terminated (average M _n ~ 580) * * from Sigma Aldrich 0.05% 4 g

Example 5

Corundum (Al ₂ O ₃ ) 65.44% 5000 g Phenolic resin 18.96 Cryolite 15.19% Baysilone polydimethylsiloxane M 50 0.45% 34 g Wacker crosslinker V90 (PDMS H-terminated) 0.05% 4 g

Example 6

Corundum (Al ₂ O ₃ ) 65.44% 5000 g Phenolic resin 18.96% Cryolite 15.10% Baysilone polydimethylsiloxane M 50 0.45% 34 g Wacker Vernetzer V24 (PDMS H-terminated) 0.05% 4 g

Example 7

Corundum (Al ₂ O ₃ ) 65.44% 5000 g Phenolic resin 18.96% Cryolite 15.10% Baysilone polydimethylsiloxane M 50 0.45% 34 g Dynasylan 9116 0.05% 4g

Example 8

Corundum (Al ₂ O ₃ ) 64.65% 5000 g Phenolic resin 18.96% Cryolite 15.19% Baysilone polydimethylsiloxane M 50 0.60% 46 g Dynasylan 9116 0.60% 46 g

The composition of the comparative example and the compositions of examples 1 to 8 are then processed further as in the prior art. That is, the compositions are compressed by means of a press and the finished specimen, in other words the finished grinding wheel or the finished grinding segment, are then cured at an elevated temperature in the temperature range described for the specified duration.

Sample segments with a size of 120 × 60 mm were produced from the compositions given above and subjected to increasing force in a 3-point flexural tensile test until they break. The specified value corresponds to the maximum load in the event of breakage.

Comparative example. Example 1 and Example 2 before aging

Comparative example

Sample number Thickness in mm Required force in kN 1 15.05 2.863 2 14.95 2.222 3 15.25 2.486 4th 15.20 2.356 5 15.35 2,896 6th 15.20 2.397 7th 15.35 2.227 8th 15.40 2.531 average 15.22 2.497

example 1

Sample number Thickness in mm Required forces in kN 1 15.45 2,689 2 15.20 2.746 3 15.35 3.164 4th 15.55 2.691 5 15.20 2.897 average 15.35 2,837 * * 2.837 kN
(= ̂ 13.61% increase compared to the non-aged blank sample 2.497kN)
(= ̂ 27.10% increase compared to the aged blank sample 2.232 kN)

Example 2

Sample number Thickness in mm Required force in kN 1 15.25 2,600 2 15.15 3.127 3 15.05 2.838 4th 15.25 3.285 5 15.40 3.126 average 15.22 2,995 * * 2.995 kN
(= ̂ 19.94% increase compared to the non-blank sample 2.497 kN
(= ̂ 34.18% increase compared to the aged blank sample 2.232 kN)

Comparative example. Example 1 and Example 2 after aging in a humidity chamber

Conditions: 48h, humidity in the atmosphere 95% at + 37 ° C

Comparative example

Sample number Thickness in mm Required force in kN 1 15.15 2.055 2 15.35 2,424 3 15.15 2.355 4th 15.25 2.081 5 15.20 2.135 6th 15.25 2.246 7th 15.20 2,466 8th 15.25 2.090 average 15.22 2,232 * * 2.232 kN
(= ̂ 10.60% reduction compared to the non-aged blank sample 2.497kN)

example 1

Sample number Thickness in mm Required force in kN 1 15.25 3.161 2 15.25 3.363 3 15.00 2,674 4th 15.15 3.522 5 15.30 2.741 average 15.19 3.092 * * 3.092 kN
(= ̂ 23.83% increase compared to the non-aged blank sample 2.497 kN
(= ̂ 38.53% increase compared to the aged blank sample 2.232 kN)

Example 2

reference Thickness in mm Required force in kN 1 15.25 2,850 2 15.25 3.124 3 15.00 3.237 4th 15.15 2.825 5 15.35 3.428 average 15.22 3.093 * * 3.093 kN
(= ̂ 23.87% increase compared to the non-aged blank sample 2.497kN)
(= ̂ 38.57% increase compared to the aged blank sample 2.232 kN)

• DIN EN ISO 7438-2012 Metallische Werkstoffe - Biegeversuch ( ISO 7438:2005 )
• DIN EN ISO 178 (2013-09) Kunststoffe - Bestimmung der Biegeeigenschaften ( ISO 178:2010 + Amd.1:2013); Deutsche Fassung EN ISO 178:2010 + A1:2013
• DIN EN 12390-5 (2009-07) Prüfung von Festbeton - Teil 5: Biegezugfestigkeit von Probekörpern; Deutsche Fassung EN 12390-5:2009
• DIN EN 843-1:2006 Hochleistungskeramik - Mechanische Eigenschaften monolithischer Keramik bei Raumtemperatur - Teil 1: Bestimmung der Biegefestigkeit
• DIN EN 843-2:2006 Hochleistungskeramik - Mechanische Eigenschaften monolithischer Keramik bei Raumtemperatur - Teil 2: Bestimmung des Elastizitätsmoduls, Schubmoduls und der Poissonzahl

The test is based on the following standards:

• DIN EN ISO 7438-2012 Metallic materials - bending test ( ISO 7438: 2005 )
• DIN EN ISO 178 (2013-09) Plastics - Determination of the bending properties ( ISO 178: 2010 + Amd.1: 2013); German version EN ISO 178: 2010 + A1: 2013
• DIN EN 12390-5 (2009-07) Testing hardened concrete - Part 5: Flexural strength of test specimens; German version EN 12390-5: 2009
• DIN EN 843-1: 2006 Advanced ceramics - Mechanical properties of monolithic ceramics at room temperature - Part 1: Determination of flexural strength
• DIN EN 843-2: 2006 High-performance ceramics - Mechanical properties of monolithic ceramics at room temperature - Part 2: Determination of the modulus of elasticity, shear modulus and Poisson's number

For a further comparison of the present invention, separating disks were produced in a known manner from the compositions of each comparative example, example 4, example 5 and example 6 and examined with a scanning electron microscope.

• 1A eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 1 in der geringsten Auflösung,
• 1B eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 4 in der geringsten Auflösung,
• 1C eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 5 in der geringsten Auflösung,
• 1D eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 6 in der geringsten Auflösung,
• 2A eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 1 in einer mittleren Auflösung,
• 2B eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 4 in einer mittleren Auflösung,
• 2C eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 5 in in einer mittleren Auflösung,
• 2D eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 6 in einer mittleren Auflösung,
• 3A eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 1 in der höchsten Auflösung,
• 3B eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 4 in der höchsten Auflösung,
• 3C eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 5 in der höchsten Auflösung,
• 3D eine Rasterelektronenmikroskopaufnahme einer Trennscheibe, hergestellt aus einer Zusammensetzung gemäß Beispiel 6 in der höchsten Auflösung.

The attached 1A until 3D show the results of these investigations in three different resolutions. Show in detail:

• 1A a scanning electron microscope image of a cutting disk made from a composition according to example 1 in the lowest resolution,
• 1B a scanning electron microscope image of a cutting disk made from a composition according to example 4 in the lowest resolution,
• 1C a scanning electron microscope image of a cutting disk, produced from a composition according to example 5 in the lowest resolution,
• 1D a scanning electron microscope image of a cutting disk, produced from a composition according to example 6 in the lowest resolution,
• 2A a scanning electron microscope picture of a cutting disk, produced from a composition according to example 1 in a medium resolution,
• 2 B a scanning electron microscope image of a cutting disk, produced from a composition according to example 4 in a medium resolution,
• 2C a scanning electron microscope image of a cutting disk, produced from a composition according to example 5 in a medium resolution,
• 2D a scanning electron microscope image of a cutting disk, produced from a composition according to example 6 in a medium resolution,
• 3A a scanning electron microscope image of a cutting disk made from a composition according to example 1 in the highest resolution,
• 3B a scanning electron microscope image of a cutting disk made from a composition according to example 4 in the highest resolution,
• 3C a scanning electron microscope image of a cutting disk, produced from a composition according to example 5 in the highest resolution,
• 3D a scanning electron microscope picture of a cutting disk, produced from a composition according to Example 6 in the highest resolution.

When looking at these recordings, it can be seen overall that the bonding of the abrasive grain, which can be seen in the recordings as a comparatively uniform, smooth surface, to the matrix in the examples according to the invention is significantly stronger than in the comparative example. This becomes more and more clear with increasing resolution based on the transition from abrasive grain to the matrix, since the boundaries, which are probably solid-solid phase boundaries, are more difficult to recognize.

As already described, this phenomenon is regarded as an indication of a direct, chemical bond of the abrasive grain in the examples according to the invention, while in the comparative example the abrasive grain is only adhesively bonded to the matrix. This is also proven by the strength tests described with the flexural tensile test before and after aging of the sample segments.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 69609709 T2 [0004]
• WO 9324272 [0005]

Non-patent literature cited

• DIN EN ISO 7438-2012 [0052]
• ISO 7438: 2005 [0052]
• DIN EN ISO 178 (2013-09) [0052]
• ISO 178: 2010 [0052]
• EN ISO 178: 2010 [0052]
• DIN EN 12390-5 (2009-07) [0052]
• EN 12390-5: 2009 [0052]
• DIN EN 843-1: 2006 [0052]
• DIN EN 843-2: 2006 [0052]

Claims (11)

Process for producing an abrasive tool with the following process steps carried out in this sequence: a) Mixing abrasive grain, organic binder and filler, b) subsequently adding one or more Si compounds from the group comprising silanes, siloxanes, silazanes and silicone resins and mixing with the raw mixture prepared in step a), followed by one c) pouring into a mold, compacting the mixture and finally d) curing the molded article produced in step c) at a temperature in the range from 100 ° C. to 300 ° C. for a period of from 10 to 70 hours to obtain the abrasive tool. Process for producing an abrasive tool with the following process steps carried out in this sequence: a) Mixing organic binder and filler, b) subsequently adding one or more Si compounds from the group comprising silanes, siloxanes, silazanes and silicone resins and mixing with the raw mixture prepared in step a), followed by a c) adding the grain and mixing with the mixture prepared in step b), then d) pouring into a mold, compacting the mixture and finally e) curing the molded article produced in step d) at a temperature in the range from 100 ° C. to 300 ° C. for a period of from 10 to 70 hours to obtain the abrasive tool. Procedure according to Claim 1 or 2 , characterized in that if only monomeric silanes with exclusively aliphatic substituents on the Si atom with a chain length of C ₁ to C ₅ are used as one or more Si compounds, an additional addition of a catalyst to accelerate the conversion of the Si compound in an amount of 0.1 to 10 wt .-% of the total amount of Si compound takes place. Method according to one of the Claims 1 until 3 characterized in that the one or more Si compounds are added to the mixture of abrasive grain, organic binder and filler in an amount between 0.1 and 25% by weight of the total mass. Method according to one of the preceding claims, characterized in that consisting of silanes, siloxanes, silazanes, and silicone resins existing group alkylsilanes, arylsilanes, fluoroalkylsilanes, epoxy silanes, acetoxysilanes, Kieselsäureester, alkylsiloxanes, Cycloalkylsiloxane, polysiloxanes, Alkylsilazane, alkyldisilazanes, polysilazanes, Methylphenylsiliconharze, methoxy-functional Methylpolysiloxanharze , and silanol functional methylphenyl silicone resins and mixtures thereof. Method according to one of the preceding claims, characterized in that the one or more Si compounds are added in dissolved or colloidally dissolved form and in fine distribution, in particular by spraying. Method according to one of the preceding claims, characterized in that the mixing takes place with the introduction of high shear forces, preferably by maintaining a high number of revolutions during mixing. Method according to one of the preceding claims, characterized in that the organic binder is selected from the group comprising epoxy resin, phenolic resin, polyamide resin, polyurethane resin, urethane acrylate or rubber, or mixtures thereof. Method according to one of the preceding claims, characterized in that organic binding agent in liquid form, in solid form or in a mixture of liquid and solid form is mixed with the abrasive grain and filler. Resin-bonded abrasive tool obtainable by a method according to one of the preceding claims. Resin-bonded abrasive tool according to Claim 10 , characterized in that the abrasive tool is a cutting, grinding or grinding wheel.

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