DE10197149B4 - Coated abrasive and method of manufacture - Google Patents

Abstract

Coated abrasive or composite abrasive coated with a layer consisting essentially of:
(a) a thermoplastic or thermosetting resin; and
(B) an inorganic anti-caking agent selected from the group consisting of metal silicates, silicon oxides, metal carbonates and metal sulfates.

Description

Background of the invention.

coated Abrasive products are used to provide a wide variety of substrates which soft, difficult-to-finish materials, like painted surfaces, may include. If These soft materials can be finished, the coated abrasive products due to premature addition not their highest Bring performance. Adding is the agglomeration of grinding waste, which the rooms between abrasive grains clog, thereby preventing the abrasive product in the Able to continue to effectively abrade the workpiece or surface. The approach of the abrasive industry is to use chemical compounds, such as metal soaps (i.e., zinc stearates, calcium stearates) as an additional cover binder layer or embedded in the top coat layer to use what is usually as the first cap binder coating referred to as. The stearate technology ensures adequate material removal and adequate anti-clogging properties. Leave metal stearates but a residue on material with low surface energy on the surface of the workpiece, possibly Can cause problems in post-processing, such as coating defects in downstream painting process.

A Contamination with this material with low surface energy can be determined by the water contact angle on the ground substrate is measured. The usual practice is with this Point to deal with is the sanded surface with Solvent wipers to clean, preferably to ensure that the entire Contamination is removed, or with a non-stearated product endzubearbeiten.

Summary the invention

It would be desirable the step of cleaning the ground surface with the solvent wipers eliminating valuable time in the painting process and money spent. Furthermore, not stearge guaranteed Products generally no long life.

According to one embodiment is a coated abrasive or a composite abrasive with coated in a layer, consisting essentially of an inorganic anti-caking agent, that selected is from the group consisting of metal silicates, silicon oxides, Metal carbonates and metal sulphates.

The Layer consists essentially of the inorganic anti-additive additive and this means that the Layer contains no additives with organic ingredients, such as they are conventional Embody anti-caking additives, including Metal salts of organic acids, Organophosphates, organosilicates, organoborates and the like. This concludes but not the presence of a cured binder component from who the vehicle is available through which the inorganic addition agent is applied becomes.

The Metal silicates can selected being from the group consisting of magnesium silicates, potassium aluminum silicates, Aluminum silicates and calcium silicates. According to one embodiment shut down the magnesium silicate talc, the potassium aluminosilicates close Mika The aluminum silicates include clays and the calcium silicates shut down Wollastonite. The silicon oxides may be selected from the group consisting of quartz glass, fumed silica and precipitated amorphous silica. The metal carbonates can Include calcium carbonate. The metal sulfates can aqueous calcium sulfate and anhydrous calcium sulfate.

The anti-caking agent may have a Mohs hardness value of less than about 7, and preferably less than about 3. The anti-loading agent may have an average particle diameter size of less than about 30 microns, and preferably in the range of between about 1 and about 20 microns. This allows the anti-caking agent to form enough small particles that combine with the grinding waste from a ground surface, such as a painted metal surface, to prevent sufficient agglomeration of grinding debris in a surface of the coated abrasive. This means that the particles of the anti-caking agent are of such a size that, during Grinding a painted surface using the coated abrasive to produce abraded grinding waste, releasing particles of the anti-load agent that bond to abrasive waste particles and inhibit the agglomeration of such abrasive waste particles.

According to one another embodiment the content of the anti-caking agent is mainly concentrated in the additional topcoat layer. For example, the content may be at least 10% by volume, and preferably at least about 60% by volume the additional cover binder layer amount.

The Anti-caking agent is preferably dispersed in a binder, which, for example, a thermoplastic or thermosetting Contains resin. The thermoplastic resin may include, for example, latex and the thermosetting resin may be selected from the group consisting from urea-formaldehyde resin systems, phenolic resin systems, epoxy resin systems, urethane resin systems and curable by means of radiation Resin systems.

One coated abrasive or a composite abrasive which a carrier layer with a first surface, an abrasive layer containing a plurality of abrasive particles, the on the first surface the carrier layer are arranged, and having a layer substantially consists of an inorganic anti-caking agent that exceeds the Abrasive layer is applied, is also provided. According to one embodiment For example, the anti-caking agent is applied to a cured size coat.

One Process for the preparation of the abrasive, such as a coated or a composite abrasive, is also provided, which attaches a variety of abrasive particles on one first surface a carrier layer and applying a substantially anti-caking agent existing layer over includes the abrasive particles.

Short description the drawings

The solution The foregoing object and advantages of the invention will be apparent from the following, more detailed description of the preferred embodiments the invention. The enclosed Drawing is not necessarily to scale, instead became greater value to the presentation of the principles of the invention.

The Figure shows a contact angle θ for a solid, a liquid and a steam.

Full Description of the invention

coated Close the abrasive those products which have abrasive grains attached to a support beam, and that can be used around the surface of an article on which they are applied, or otherwise remove.

Of the Support beam of a Coated abrasive can be rigid, but is generally flexible and usually contains a fabric of material such as paper, cloth, fibrous padding, polymer film, vulcanized fiber, or a combination of such materials and the like. In some applications, the support beam initially has a collection of loose Fibers, to which the abrasive grains with or without further Binder material can be added to an abrasive cloth for disposal to put that everywhere abrasive grains having. The loose collection of fibers and grains can be pressed together if no adhesive binder is present, or otherwise attached or hardened when a binder is present, the coated one To form abrasive.

The abrasive grains may generally be any material which has the ability to abrade the workpiece, and usually comprises sand, flint, corundum, metal oxides such as alumina, aluminum-zirconia, ceramic alumina, diamond, silicon carbide, garnet, rouge, polishing red and like. The grains typically have sharp edges that act as the abrading agent, but the quality and quantity of the sharp edges depends on the intended use. The grains may be embedded in or mixed with the backing, but are more often attached to the backing by means of a suitable binder material. The granules may be applied to the tissue in a particular pattern or blended with the tissue, or they may be randomly distributed. Usually Careful action is taken to ensure that the coated abrasive has a fixed grain with a proper distribution of grain cutting edges in one or more layers.

The Binder material is generally any suitable material, that can act to keep the grains to attach to the support beam, and the most resistant are enough to invalidate the abrading process do. Typical binder materials include phenolic resins, skin glues, Varnishes, epoxy resins, acrylates, polyfunctional acrylates, urea-formaldehyde resins, trifunctional urethanes, polyurethane resins, lacquers, emailes and each from a big one Variety of other materials which have the ability to place the grains in stabilizing adhesive relationship with the support beam one. In general, the binder material is carefully selected to a maximum efficiency of the coated abrasive for the ins Eye-catching surface to ensure. The choice of binder materials will ensure that that these softening or burning or both due to overheating can resist and yet ensure adequate attachment.

The grains can sprayed on the binder material or otherwise with the Binder material coated and placed on or above the support beam, or the support beam can coated with the binder material and the grains thereafter be arranged on it. Many alternative forms of support beams, grain materials, Binder materials, means for arranging the grains the support beam, means for fixing the grains and similar are known in the art and are considered as modifications, which are considered to be within the scope of this invention.

in the general is in the production of a conventional coated abrasive a carrier (with or without pretreatment), a base layer of a binder resin is applied and, while the resin is still sticky, abrasive grains are applied over the base coat, and the binder is cured, around the grains to stay in place. A capstock layer that is essentially a binder resin and optionally fillers, grinding aids and similar contains will then over the grains applied and hardened. The main function of the top coat layer is to keep the grains on Anchor space and allow it to grind a workpiece, without being pulled out of the structure of the coated abrasive to become before their schleiffähigkeit exhausted has been. In some cases An additional size coat is applied to the size coat. The function of this layer is to be on the surface of the coated abrasive to arrange an additive, which is a ensures special property like an elevated one Grindability, Surface lubrication, Anti-static properties or, in this case, anti-clogging properties. The additional cover binder layer plays in general, but not necessarily, irrelevant while holding the grains in place on the coated abrasive.

The Additive can be used as a dispersion in a binder (which is subsequently cured) or in a liquid Dispersion which simply dries and leaves the additive on the surface. According to one embodiment contains the binder is a thermoplastic or a thermosetting resin. For example, the thermoplastic resin may include latex, and the thermosetting resin may be selected from the group consisting from urea-formaldehyde resin systems, phenolic resin systems, epoxy resin systems, urethane resin systems and curable by means of radiation Resin systems. With some additives, the adhesion to the surface can be achieved be without one Dispersion medium is necessary.

According to the present Invention can the anti-caking agents that over the capstock layer are applied, consisting of the group from metal silicates, silicon oxides, metal carbonates and metal sulfates selected become. The metal silicates can selected are selected from the group consisting of magnesium silicates, potassium aluminosilicates, Aluminum silicates and calcium silicates. According to one embodiment shut down The magnesium silicate talc, the potassium aluminosilicates include Mikas The aluminum silicates include clays and the calcium silicates shut down Wollastonite. The silicon oxides can be selected from quartz glass, fumed silica and precipitated, amorphous silica. The metal carbonates may include calcium carbonate. The Metal sulfates can aqueous calcium sulfate and anhydrous calcium sulfate.

According to the present invention, the inorganic anti-caking agent during use appears to release fine particles which coat fine grinding waste particles produced by the grinding process, thereby preventing them from sticking together to form troublesome larger particles caught on the coated abrasive surface ( known as " clogging "), which reduces the effectiveness, and thus reduces the clogging of the coated abrasive without causing the problems associated with the use of conventional stear ceased anti-caking layers are. With such additives, a fine layer of low energy material is smeared on the ground surface, which makes subsequent painting or subsequent polishing of the surface very difficult if this layer is not removed.

The Anti-caking agent of the present invention is according to a embodiment relatively soft, it has for example a Mohs hardness value less than about 7, and preferably less than about 3. According to one embodiment the adding agent has a mean particle diameter size range less than about 30 microns, and preferably between about 1 and about 20 microns, since materials with finer particle sizes better seem to work as an anti-caking agent.

It it is believed that it a mechanism of anti-caking agent to ensure a non-loading property is to prevent abrasive particles from sticking together, whereby the clogging is reduced. This approach generates during the Grinding a fine dust while without the inorganic anti-caking agent the grinding waste tends to Balls or big ones Chips too form, which are absorbed between the grain particles, which prevent effective grinding and the life of the coated Reduce abrasive. The difference in the appearance of the Abrasive waste, which when stiffened with stear and non-steared Results in products is visible.

According to the present Invention is the concentration of anti-clogging agent in one grinding surface the additional cover binder layer is greater than about 10% by volume, and preferably greater than about 60% by volume. This ensures that there are enough anti-caking agents is to be effective to form the fine dust, which prevents the grinding waste from bunching.

The Anti-caking agent may be mixed with other abrasives, such as composite abrasives (not woven) can be used.

Example 1: Hydrous Magnesium silicate (talc) with different average particle sizes

in the following example and the following is a conventional, coated standard abrasive used. The carrier material is an A weight paper and the base coat and the make coat contain a urea-formaldehyde binder.

In In any case, the abrasive particles P320 are alumina. On this Base coated abrasive becomes an anti-caking additive applied containing additional cover binder layer. In one case was for comparison purposes no additive applied. In a second case, a zinc stearate applied additional cover binder layer applied and in three others make the applied coating was hydrous magnesium silicate (Talc) with different particle size. The additives were called Dispersion applied in latex and water.

The Coated abrasives were then used, an acrylic plate using a two-speed grinder for six two-minute Sand down contacts. The sanding was done with a 12.7 cm (5 Inch) disk at a load of 4.5 kg (10 lb). The Amount of sanding after the total sanding time of 12 minutes became recorded and the grinding power was determined as a percentage the control. The average roughness Ra (the roughness arithmetic mean) were also determined. The Results are given in Table 1 below, which shows that talk the same way effective is like the more usual Zinc stearate.

Table 1

Example 2: Hydrous Magnesium silicate (talc) Supreme HT in various particle sizes

The The following tables show a comparison of the grinding performance Supreme HT Talk with zinc stearate and a control without anti-caking agent for aluminum oxide coated Abrasives of particle sizes P80, P180 and P320 (Table 2, Table 3 and Table 4, respectively). The results show that the Abrasion with the incorporation of the anti-caking agent according to the invention was higher compared to Basic control, especially for finer grain sizes.

Table 2

Table 3

Table 4

Example 3: Amorphous silica, Calcium silicate (wollastonite) aluminum silicate (clay) and potassium aluminum silicate (Mika)

One conventional, with aluminum oxide of grain size P320 A weighted standard coated abrasive is used. This base coated abrasive becomes an additional size coat, containing an anti-caking additive, either amorphous silica, Calcium silicate (wollastonite), aluminum silicate (clay) or potassium aluminosilicate (Mika), upset. The grinding results given in Table 5 below show that the Abrasion with the incorporation of the anti-loading agent according to the present invention Invention over the basic control higher was.

Table 5

Example 4: Calcium sulfate (anhydrous and hydrous)

One conventional, with aluminum oxide of grain size P320 A weighted standard coated abrasive is used. This base coated abrasive becomes an additional size coat, containing an anti-caking additive of calcium sulfate (anhydrous or hydrous) applied. The ones given in Table 6 below Results show that the Attrition with the incorporation of the anti-caking agent according to the present invention Invention over the basic control higher was.

Table 6

Example 5: Water contact angle of polished painted panels after sanding

primed Plates were coated with P320 grain size Abrasives with an additional topcoat layer as in the examples 1 to 4 ground. The same grinding procedure was used used with any coated abrasive. A drop of water was then placed on each of the freshly ground plates and also on an uncut plate, and the contact angle (Θ) was recorded as described in the figure. The contact angle is the angle between the surface a liquid and the surface a fixed plane at the line of contact. A higher contact angle indicates less wetting. The results are given in Table 7, which clearly shows that the with the coated according to the invention Abrasives ground plates essentially the same or a smaller contact angle than the plates, the using a coated abrasive without the anti-addition layer were ground. The coated abrasive with the conventional Zinc stearate anti-Zusetzschicht clearly lagged behind with low surface energy whose presence is due to a very high water contact angle is shown. The consequence of this is that applied to such a surface Colors the surface do not wet easily and this leads to surface defects.

Table 7

Of the Water contact angle on an uncut plate was 69 degrees.

While these Invention in particular with reference to preferred embodiments As has been shown and described, it will be apparent to those skilled in the art that various changes can be made in the form and details without departing from the scope of the invention to depart, which is covered by the appended claims.

Claims (24)

Coated abrasive or composite abrasive coated consisting of a layer consisting essentially of: (a) one thermoplastic or thermosetting resin; and (b) one inorganic anti-caking agent selected from the group consisting from metal silicates, silicon oxides, metal carbonates and metal sulfates. An abrasive according to claim 1, wherein the metal silicates selected are from the group consisting of magnesium silicates, potassium aluminosilicates, Aluminum silicates and calcium silicates. An abrasive according to claim 2, wherein the magnesium silicates Include talc. An abrasive according to claim 2 wherein the potassium aluminosilicates Include Mika. An abrasive according to claim 2, wherein the aluminum silicates Include clays. The abrasive article of claim 2, wherein the calcium silicates Include wollastonite. An abrasive according to claim 1, wherein the silicates selected are from a group consisting of quartz glass, fumed silica and precipitated, amorphous silica. The abrasive article of claim 1, wherein the metal carbonates Include calcium carbonate. The abrasive article of claim 1, wherein the metal sulfates include hydrous calcium sulfate or anhydrous Include calcium sulfate. The abrasive article of claim 1, wherein the anti-caking agent a Mohs hardness value less than about 7. The abrasive article of claim 1, wherein the anti-caking agent an average particle diameter size of less than about 30 Having micrometers. The abrasive article of claim 11, wherein the anti-caking agent a mean particle diameter size of between 1 and 20 microns having. The abrasive article of claim 1, wherein the anti-caking agent concentrated primarily in the abrasive coating layer is. The abrasive article of claim 1, wherein the anti-caking agent at least 10% by volume of the abrasive coating Make up shift. The abrasive article of claim 14, wherein the anti-caking agent at least 60% by volume of the abrasive coating Make up shift. An abrasive according to claim 1, wherein the thermoplastic Resin latex includes. The abrasive article of claim 1, wherein the thermoset Resin selected is selected from the group consisting of urea-formaldehyde, phenol, Epoxy, urethane and radiation-curable Resin systems. An abrasive according to claim 1 comprising: (A) a carrier layer with a first surface; (B) an abrasive layer having a plurality of on the first surface of the backing arranged abrasive particles; such as (c) the substantially from a thermoplastic or thermosetting resin and a inorganic anti-caking agent existing over the layer Abrasive layer is arranged. Method for producing an abrasive, full: (a) attach a plurality of abrasive particles on a first surface a carrier layer; and (b) depositing a layer over the abrasive particles which essentially from: (i) a thermoplastic or thermoset Resin; and (ii) an anti-caking agent selected from the group consisting of metal silicates, silicon oxides, metal carbonates and metal sulfates. The method of claim 19, wherein the metal silicates selected are from the group consisting of magnesium silicates, potassium aluminosilicates, Aluminum silicates and calcium silicates. The method of claim 20, wherein the magnesium silicate Includes talc. The method of claim 19, further comprising the step of depositing an intermediate layer containing a thermoplastic or thermosetting resin over the abrasive particles before depositing the layer of step (B). The method of claim 19, comprising the wide the step of forming an abrasive surface of the slime such that yourself the anti-caking agent is mainly on it. The method of claim 19, further comprising the step of dispersing the anti-caking agent in the thermoplastic or thermosetting resin.