JPS63234037A - Polishing article and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is directed to the production of erodable aggregates containing abrasive grains.
rates > , more particularly relating to abrasive products containing erodible aggregates.

Conventional coated abrasives typically consist of a single layer of abrasive grains adhered to a backing. At most only 15 of the particles in the layer
It has been found that only % is utilized for workpiece removal. Therefore, approximately 85% of the particles in the layer are wasted. Furthermore, coating TAL! The backing, which is one of the more expensive components of the i-agent, must also be disposed of before its useful life.

To overcome this problem of waste, relatively high proportions of abrasive grains have been utilized and numerous attempts have been made to distribute the abrasive grains in such a way that the life of the coated abrasive product is therefore extended. Longer lifespans result in fewer belt or disc changes by the operator, thus saving time and reducing labor costs. Simply depositing a thick layer of abrasive grains on the backing is not a solution to the problem since the particles below the top grains are not utilized.

The prior art describes several attempts to distribute abrasive grains in applied abrasives to extend the life of the product. u, s, Re, 29.808 consists of a number of hollow bodies, the walls of which contain abrasive grains and bonding means that interconnect the abrasive grains to the wall surface, thereby providing a large number of hollow bodies during grinding. Abrasive materials are described in which fresh abrasive grains are continuously supplied to the abrasive surface, and the abrasive action of the abrasive surface depends solely on the particle size of the abrasive grains.

u, s, P, 2.806.771: is essentially a grind m,
An abrasive article is disclosed comprising a phenolic resin bonding it and thin walled hollow spheres 0.025 inch in diameter distributed throughout the resin bond and among the abrasive grains. The spheres constitute 1-30% of the volume of the article.

U, S, P, 4.311, 489 Niha, each Til liakor coat consisting of a lignified solid '/li aggregate of fine abrasive grains and an inorganic, brittle cryolite matrix and size Abrasive products are described which are secured to the backing by a coat (SiZecoat). This agglomerate has an irregular surface that provides a strong bond to the manufacturer and size coat, and during grinding, the agglomerate is gradually worn away by gradually removing the dulled abrasive grains from the bond. be able to.

DE 2,417,196 describes a coated abrasive article consisting of an abrasive body on a support. The abrasive body consists of a hollow body, the walls of which consist of a bonding agent and abrasive grains. The hollow body is torn during the grinding process, so that the walls of the hollow body act on the material being ground. The wear of the particles is therefore distributed over the entire surface area of the support. Although the products described in these patents are useful, higher utilization of abrasive grains in coated TA abrasives is desired in the industry.

In one embodiment, the present invention includes a binder, preferably a resinous binder, and an erodible matrix comprising hollow bodies that facilitate breakage of the aggregates during use in an abrasive article. Includes erosive aggregates containing individual particles of abrasive minerals distributed therein.

The hollow bodies preferably consist of hollow microspherical particles formed from glass. This hollow body makes the aggregates sufficiently resistant to avoid premature failure under harsh abrasive conditions, yet
Under these polishing conditions, the agglomerates are sufficiently soft to break up.

In the agglomerate of the present invention, the spent individual grains and matrix fall off during the polishing operation and new grains are exposed to the workpiece, thus providing long service life to the abrasive product in which they are used. High material removal can be achieved by imparting longevity. Coated abrasives containing the agglomerates of the present invention have been found to be useful in both finishing operations as well as stock removal operations. Important advantages of coated abrasives made using the agglomerates of the present invention are good service life, effective utilization of abrasive particles and ease of use in 11jiII environments such as environments using water, oil or a combination of both. It is possible.

In other embodiments, the present invention includes methods for making the aforementioned aggregates and abrasive products containing the same, such as coated abrasives and grinding wheels. The hollow bodies prevent settling of the individual particles during the curing process used during the manufacture of the aggregates and ensure retention of bulk and shape of the aggregates.

Referring to FIG. 1, there is shown a collection body o which is erodible and has numerous voids within it.

The essential components of the aggregate 10 include hollow bodies 11 , individual abrasive grains 12 , and a binder 13 , with the hollow bodies 11 and abrasive grains 12 randomly distributed within the binder 13 . For the aggregate to be erodible, both the hollow body and the binder must be erodible. The volume per unit weight of the aggregate is greater than the volume per unit weight that would be expected for an aggregate containing the same components but without voids. As used herein, the term hollow means having a space or void within a wall that is substantially impermeable to liquid, since a porous body is permeable to liquid. The term “hollow” is the same as porous! There is no intention of using it as a word.

The important function of the hollow body is to break up the used open ring aggregates and facilitate the exposure of additional individual particles when the useful life of the spent particles has ended. The hollow body can be of any shape, such as cylindrical, pyramidal, cubic, but is preferably ellipsoidal with thin walls that confine the void. As used herein, "ellipsoid" means a spherical or elliptical shape. Spherical or elliptical shapes are preferred because of their relatively good packing in the conjugate. The hollow bodies must have a very small diameter so that a large number of them can be incorporated into each combination. For spherical particles, the diameter of each particle may range from about 5 to 150 μm, and the average diameter preferably ranges from about 30 to about 100 μm.

Preferably, the microspherical particles are hollow glass bubbles. The true bulk density of the glass hollow body typically ranges from about 0.1 to about 0.6
It is in the range of 9/cc. True bulk density is measured by dividing the volume of the hollow body by the actual volume of the hollow body.

The hollow body must be pressure-resistant, i.e.
It must have sufficient crushing strength to prevent breakage of the agglomerates during the manufacturing process of the agglomerates and during storage of abrasive products made therefrom. The hollow body must also have a crush strength equal to or significantly lower than the binder to facilitate erosion of the aggregates. Preferably, the crush strength of the hollow body is no greater than about 15.0 OOD8i and no less than about 100 psi. The crushing strength used in the water manual is ASTM D3102-
Measured by 78.

It is highly desirable that the hollow body does not adversely react with the resin or the resin containing the binder so that the binder is not weakened or the hollow body is unduly softened or hardened. The physical structure of the hollow body, when combined with a binder in an aggregate, preferably provides a hollow body/binder complex containing sufficient void volume to facilitate disruption of the ring-open aggregate in an abrasive operation. It is preferable that the property is such that the following can be obtained. During the polishing operation, the voids that appear in the aggregate are
It serves to remove the ground debris and to increase the pressure of the individual abrasive grains on the workpiece, ensuring the destruction of the agglomerates.

Hollow bodies suitable for the present invention are sold under the trade name [3M] Glass Bubble and are manufactured by Hinnes Ota Hinin.
aand HanljfaCttlrin! J Com
It is commercially available from pany. They consist of water-insoluble, chemically stable glasses. These are closed cell cells with an average diameter of less than 70 μm.

Abrasive grains suitable for the present invention are well known in the art and include, but are not limited to, aluminum oxide (A12
03), zirconium oxide, garnet, diamond sand, corundum, alumina; includes zirconia, silicon carbide, carbides such as boron carbide, nitrides such as cubic boron nitride, diamond, ruby, flint, modified ceramic aluminum oxide, etc. . Mixtures of abrasive grains in individual agglomerates can also be used.

The arrangement of individual abrasive grains in the aggregate is “independent” (c1
osed), that is, the individual particles are in contact with each other, or open (ODen), that is, the individual particles may be spaced apart.

The 1m ability of the bonding agent is to bond the individual abrasive grains with the microspherical particles and limit the brittleness and fracture properties of the aggregates. It is desirable that the matrix erode without softening, flowing or melting.

Binders suitable for the present invention are well known in the art and include:
and, including but not limited to, phenol IM [i,
Includes urea formaldehyde resins, phenol formaldehyde resins, epoxy resins, and alkyd resins. Although synthetic organic binders are preferred, natural organic binders such as glue, and inorganic binders can also be used.

Grinding aids can also be incorporated into the agglomerates. Representative examples of grinding aids suitable for the aggregates of the present invention include cryolite (Na3
AIFB), inorganic halides such as potassium borofluoride (KBF4), inorganic sulfides, and chlorinated hydrocarbons.

Conventional fillers can also be incorporated into this agglomerate. A typical example of such a filler is calcium carbonate.

The layers of each essential component in the aggregate can vary, but preferably from about 0.3 to about 8% by weight of microsphere particles, from about 95 to about
about 85% by weight abrasive minerals, and about 5% to about 30% by weight
range of binders. As the concentration of binder decreases, the fragility of the aggregates increases.

The aggregates preferably have a maximum dimension in the range of 150 to 3000 um. If the individual abrasive grains are very fine, for example equal to Pl 80 (FEPA-Horn), there will be 10 to 1000 individual grains in each agglomerate. If the individual abrasive grains were equal to P36, there would be 2 to 20 particles in each aggregate. The grade and type of individual abrasive grains are not essential; grades typically range from P24 to P1000.

Agglomerates are typically irregularly shaped, but they can be formed into spheres, ellipses, ovals, pellets, squares, or other conventional shapes.

The erodibility properties of the aggregate, ie, the rate of failure or erosion under a given load, can be varied by varying the resinous binder and abrasive material, each themselves, relative to each other, or both. For example, aggregates with a relatively hard binder will erode slower than aggregates with a relatively softer binder, and aggregates with a relatively high percentage of binder will erode more slowly than those with a relatively softer binder. Erosion is slower than aggregates containing .

The aggregate of the present invention can be produced by the following method.

The abrasive grains, resin and hollow body are introduced into a mixing vessel and stirred until the resulting mixture is homogeneous. A preferred composition for making the binder is 100 parts hollow bodies, 900 parts water, 1100 parts Ifll binder and 6600 parts by weight Ifll binder.
Contains ~10.00011 parts of abrasive minerals. Is the resulting mixture too stiff or too thick? Preferably, there is sufficient liquid in the mixture so that it does not become 1llJ. Most resins contain sufficient liquid to allow proper mixing.

After completion of the mixing step, the mixture is solidified, preferably by heat or radiation. Coagulation occurs by removing liquid from the mixture. In the case of resinous binders, coagulation also occurs due to curing of the resin. After the mixture has solidified, it is crushed into agglomerates and sized to the desired size. Suitable equipment for this process includes conventional show crushers and roll crushers.

The crushing and classification steps necessary to obtain the 'am bodies as described above result in agglomerates in an undesirable size range, which are either added to the new dispersion and recycled or discarded. Coat the aggregate Tl1Il! When used in the production of pharmaceutical products, coating through a screen can be used to remove excessively large agglomerates.

The aggregates of the present invention can be used in bonded abrasive products such as coated abrasive products, grinding wheels, nonwoven abrasive side products, and other products in which abrasive grains are typically used.

Individual abrasive grains can be used together with the agglomerates of the present invention, the proportion of individual abrasive grains thus used being 7 in the agglomerate mff1.
It can be used at a high rate of 0%.

A coated abrasive that can be produced using the aggregates of the present invention is shown in FIG. As shown in FIG. 2, the coated ljI lubricant includes a backing 14. The top coat of the backing 14 is a make coat 15 in which the aggregates 10 of the present invention are embedded. A size coat 16 is applied over the make coat 15 and aggregate 10.

In the case of a coated abrasive product, the agglomerate is applied to a backing to form a coated abrasive. The backing can be any suitable material that is compatible with the components of the aggregate and maintains its integrity under curing and polishing conditions. Preferably, the backing is in the form of a conformable, fillable sheet. Backings suitable for the present invention are well known in the art and include parcant fibers, polymers, papers, nonwovens, knitted fabrics, and foils. The coating agent is applied by applying the coating onto the backing, drop coating the conjugate onto the make coat, applying the size coat, and then applying the coating onto the backing.
Application may be by conventional methods such as curing of the coating so applied. Make coats and size coats can be made using conventional materials such as phenolic resins, urea formaldehyde resins, glues, and varnishes. Examples of make coats and size coats suitable for the coated abrasive of the present invention can be found in te;the
tser u, s, P, 4.314.827. Care must be taken to ensure that the size coat does not adversely affect the erodibility of the aggregate, ie, the size coat must not spill onto the applied vR abrasive. Alternatively, in many cases a size coat is not necessary, especially if an aggregate resin binder is normally used in the preparation of the size coat. The use of radiation curable resins for the production of make coats, size coats, or both is also contemplated. An example of a radiation II curable VTM may be found in Application No. 17, filed August 7, 1985.
1763.33HC, the disclosure of which is a reference for the radiation curable resins described herein.

The grinding wheel is TL, which was used as a reference for the water 1I118 mentioned above.
s, P, 4.314.827(7)'il Example 47.

Abrasive articles containing the agglomerates of the present invention benefit from longer life due to either or both efficient utilization of abrasive grains and/or higher particle loads. coating 1i11f
'J! The abrasive product can continue to grind for long periods of time that would not be useful with a single layer of abrasive grain. Agglomerates also provide, for a given size of the individual abrasive grains, a relatively high total amount of particles that can be applied to a given area of the coated abrasive product.

The invention is briefly illustrated by the following non-limiting examples.

Example 1 In this example, the aggregate of the present invention was prepared. The II manufacturing method will be explained.

Abrasive grains (heat treated!) llAl2O3, grade P120.200
0g), resin binder (phenol formaldehyde, 2
009), and hollow glass microspheres (“3M” glass bubbles, HinneSOta Mining and) 1
25 g), available from anuraCtt+rinOcompany, were introduced into the blade mixer and the resulting mixture was stirred with the blade mixer for 10 minutes.

The mixture, which was in the form of a dough, was then removed from the mixer and then crushed into small pellets about 1/4 inch long to be sized to easily fit into a crusher after hardening. This pellet was then heated at a temperature below 200 °C for 14
Allowed to cure for hours. The hardened pellet is then crushed and 1
It passed through the 8-mesh screen, but the size was such that it could not pass through the 32-mesh screen.

Examples 2-5 The aggregates of Examples 2-5 were prepared by the method used to prepare the aggregates in Example 1, with the only exception being the strength of the glass microspheres. Table 1 shows the crush strength of the microspheres of the aggregates of Examples 1 to 5.

Table 1 1. Globular strength psi) Coat the rI1w agent by first applying a make coat of uniform thickness to a thickness of 30 mils to a diameter finch parcant eyeper disk. L.

Ta. Make coat is calcium carbonate filled phenol S
It was on the + side (58% CaC03). The aggregates were then drop-coated uniformly onto the make-coated discs. The make coat was precured for 1 hour at a temperature below 200°C. A size coat was then applied uniformly over the aggregate layer. Size coat is cryolite-filled phenolic resin (5
0% cryolite). The make coat and size coat were cured under 200°C for 12 hours.

The agglomerates of Example 1 were used to prepare coated abrasives of Example 11Ml1!46 and 11;
and 12; the agglomerates of Example 3 were used to make the coated abrasives of Examples 8 and 13; Used to make coated abrasives: The aggregate of Example 5 was then used to make coated abrasives of Examples 5 and 10.

The weights of the make coat, size coat, and aggregate coat of the coated abrasive of each example are shown in Table 1.

Table ■ Comparison 6 6.1 7.6 13.2 7 5.1 5.5 13.2 8 4.2 6.8 14.5 9 5.0 6.1 14.3 10 5.2 6 .0 13.7 11 5.5 5.8 13.5 12 5.1 5.7 12.7 13 5.7 6.0 14.4 14 4.8 5.7 13.0 15 5.6 5 .9 12.9 The coated abrasives prepared in Examples 1 to 5 were tested to measure the expected total amount of cut on a given workpiece. The results obtained in these tests are shown in Tables 1 and 1V. In Table 1, the workpiece was 1018 mild steel. In Table 1, the workpiece was 304 stainless steel.

Table 1 comparison 17.00 31.00 1
oox 3.0G6 14.0G
193.00 623% 16.007 1
7.00 132.00 426% 12.008
19.00 92.00 297% 10
．． 0G9 19.00 96.00 310%
9.00.10 20.00 90.00
290% 10,001, versus ffl is 3M-ITE
Coating 1iIIr! It was drug I. The abrasive grains were Al2O3, grade P120. The resin binder was a phenolic resin.

2. This test was conducted at a cutting speed of 6. Measured when OOg/pass or less.

Table 1 V comparison 7.00 16.00 10
0χ 3.0011 11.0G 3
0.00 188 pieces 5.0012 11.
00 33.00 206χ S,OOl 3
12.0G 31.00 194% 5.
0014 11.00 30.00 188%
5.0G15 9.00 25.00,
156% 4.001, control was 3M-ITE coated abrasive. The abrasive grains were A1□03 and grade P120. The resin binder was a phenolic resin.

2. The test was measured at a cutting speed of 5.00 g/pass or less.

It will be seen from the data in Tables 1 and 1V above that all of the coated abrasives of this invention outperform the control with respect to total cutting.

Example 1 This example compares the coated abrasive of the present invention with a conventional fiber disc.

The fiber disc was manufactured by the method shown in Example 1, with the following differences: Makeko upper mold suspension:
8g Size coat weight: 6g Agglomerate coat 1: 13.29 Agglomerates, by weight, contain 6% resin binder (phenol formaldehyde), 6% cryolite, 1% hollow glass microspheres (r3MJ glass) bubble, 500 psi crush strength) and 87% heat treated Al2O3, grade 80.

Discs of the invention and conventional discs (r Norz
available from onJ Norton Couany)
Both were tested on a 10.18 mild steel workpiece. The individual abrasive grain grade of the conventional disc was 80.

The results are shown graphically in FIG. From the graph of FIG. 3, it can be seen that the fiber disc of the present invention, indicated by line A, has a lower grinding time than the conventional fiber disc, indicated by line 8, both in terms of grinding time before becoming unusable and in cutting speed during its service life. You can see that it is excellent.

Various modifications and variations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of the invention, and the present invention is clear! It should not be construed as unduly limited to the illustrative embodiment shown in FIG.

[Brief explanation of the drawing]

FIG. 1 schematically shows a cross-section of an aggregate according to the invention having a relatively intermediate binder. FIG. 2 is a diagram schematically showing a cross section of the coated rI11 agent of the present invention. FIG. 3 is a graph comparing the cutting speed as a function of time of a coated abrasive of the present invention to the cutting speed as a function of time of a coated abrasive of the prior art.

Claims (22)

[Claims] (1) consisting of an erodible aggregate comprising numerous individual particles of an abrasive mineral randomly distributed in an erodible matrix consisting of very small, erodible, crush-resistant hollow bodies and an erodible binder; An abrasive article characterized by: (2) the aggregate contains from about 60 to about 95% by weight of individual abrasive grains, from about 0.3 to about 8% by weight of hollow bodies, and from about 5 to about 30% by weight of a binder; Items listed in Item 1. (3) The article of claim 1, wherein said binder is a resin binder. 4. The article of claim 1, wherein said binder is selected from the group consisting of phenolic resins, urea formaldehyde resins, phenol formaldehyde resins, epoxy resins, and alkyd resins. (5) The article according to claim 1, wherein the hollow body is made of glass. (6) The hollow body is spherical, and about 5 to about 15
The article of claim 1 having a diameter in the range of 0 μm. (7) The hollow body has a pressure of about 100 to about 15,000 psi.
The article of claim 1 having a crush strength in the range of . (8) comprising a large number of individual particles of an abrasive mineral disposed in an erodible matrix consisting of a hollow body and a binder;
Erodible aggregates suitable as abrasive products. (9) The agglomerate comprises from about 60 to about 95% by weight of individual abrasive grains, from about 0.3 to about 8% by weight of hollow bodies, and from about 5 to about 3% by weight of individual abrasive grains.
Agglomerate according to claim 8, containing 0% by weight of binder. (10) The aggregate according to claim 8, wherein the binder is a resin binder. 11. The aggregate of claim 10, wherein said binder is selected from the group consisting of phenolic resins, urea formaldehyde resins, phenol formaldehyde resins, epoxy resins, and alkyd resins. (12) The aggregate according to claim 8, wherein the hollow body is made of glass. 13. The aggregate of claim 8, wherein said hollow bodies are spherical and have a diameter ranging from about 5 to about 150 μm. (14) The hollow body has a weight of about 100 to about 15,000 p.
Agglomerate according to claim 8, having a crushing strength in the range of si. (15) A coated abrasive article comprising the aggregate of claim 8 secured in a backing. 16. The coated abrasive article of claim 15, wherein said aggregate is secured to said backing by a make coat and a size coat. (17) A bonded abrasive article comprising the aggregate of claim 8. (18) (a) preparing a mixture of an abrasive mineral, a binder, and a hollow body; (b) solidifying the mixture; and (c) processing the solidified mixture to form aggregates. 9. The method for producing an aggregate according to claim 8, comprising the steps of: (19) Claim 18, wherein the binder is a resin binder.
Section method. 20. The method of claim 19, wherein said binder is selected from the group consisting of phenolic resins, urea formaldehyde resins, phenol formaldehyde resins, epoxy resins, and alkyd resins. 21. The method of claim 18, wherein said coagulated mixture is treated by crushing to form agglomerates of desired size. 22. The method of claim 18, wherein said mixture of step (b) is solidified by heat.