JPS60104654A - Expanded organopolysiloxane abrasive material - 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 Field of the Invention This invention relates generally to foam abrasives and methods of making the same. More particularly, this invention relates to a foamed organopolysiloxane abrasive having abrasive grit uniformly dispersed within the foamed organopolysiloxane.

BACKGROUND OF THE INVENTION A wide variety of materials are available for use in polishing and polishing surfaces for purposes such as material removal.

Abrasives are generally classified into two types: coated or bonded. Coated abrasives have particles of abrasive or polishing material - hereafter referred to as abrasive - present as a thin coating on the surface of a body material, which can be paper, cloth, net, metal, resin, etc., and then coated with a suitable coating. Bonded to the body material by an adhesive or binder vehicle. Bonded abrasives consist of an abrasive dispersed within a bonding vehicle preformed in the form of various solid bodies and then cured or solidified for use in solid form.

Although coated and bonded abrasives have been used for many years, they have not been completely satisfactory for many applications. For example, coated abrasives become increasingly worn to expose the underlying body material, thereby providing a nearly uniformly polished and polished surface. Bonded abrasives are generally dense, hard solid bodies that become harder during use. In many cases, many polymeric materials used as binders and adhesives undergo some degree of thermal decomposition as the temperature near the abrasive working surface increases locally, resulting in polishing or polishing. This results in staining of the substrate being treated and a reduction in the grinding, polishing or polishing effect.

Additionally, in bonded abrasives, due to the method of dispersing the abrasive in the binder, or in coated abrasives, due to the adhesive or binder vehicle used to adhere the abrasive to its surface. Additionally, the accessibility of abrasive grits or grains to surfaces undergoing processes such as polishing, grinding, polishing, etc. is poor. For the reasons mentioned above,
Many prior art abrasives must be recoated or reworked or discarded, resulting in increased costs due to downtime or material replacement.

In order to overcome many of the drawbacks mentioned above, it has been proposed to use abrasive foams prepared by incorporating abrasive grit into a foamable material prior to its foaming (U.S. Pat. Nos. 3 and 2).
52,775).

According to this method, a foam containing abrasive grit substantially uniformly distributed throughout can be produced in situ. U.S. Pat. No. 3,653,859 also teaches that cells or pores in a preformed foam material are impregnated with a slurry of an abrasive and a binder or adhesive, which is dried and cured. The use of abrasive foams containing an abrasive material bonded to the foam material by a binder in the cells or pores has been proposed. According to this latter method, the distribution of the abrasive grit material is only as uniform as the distribution of the pores or cells within the foam material, and the integrity of the abrasive material is solely within the pores or cells. depending on the bonding agent or adhesive used. In most cases, these cellular or foam abrasives are made from foamable phenolic and epoxy resins. In many respects, foams have such low degrees of bonding that they must be mounted or bonded to a more durable support to be effective as an abrasive material.

No. 3,252,775 describes a type of abrasive wheel made from a soft, low density polyurethane foam, but this type of abrasive shed has poor strength and poor wear resistance. sexual and not commercially successful.

For this reason, the art commonly uses dense and reinforced materials to produce suitable abrasives and polishes, such as those described in U.S. Pat. No. 4,150,955. It has been recognized that there is a need to use high density polyurethane compositions cast into periods of reinforcement such as. Further, in the prior art, the presence of foam in the final buffing car is undesirable, as disclosed in U.S. Pat. No. 4,128.
,972. U.S. Patent No. 4,
128,972, gas cells aid in cooling the grinding wheel through better heat transfer, but void cells reduce the physical integrity of the grinding wheel and deformation and expansion are more and more experienced and the unit abrasive It is stated that the cohesive forces that support the grits in the tool and against each other are known to be substantially weakened. Therefore, the prior art generally teaches that the presence of blowing agents during adhesive elastomeric bonding should be avoided.

Many prior art abrasives and polishes have been made by incorporating abrasive grits or polishing media into silicone resins or rubbers.

These are described, for example, in U.S. Pat. Nos. 3,528,788, 3,982,359, 4,162,900 and 4,307,544.

In the prior art described in the above-mentioned patents using silicone rubbers or elastomers as the binder medium, most organic polymers and even silicone resins exhibit some degree of thermal decomposition leading to fouling and reduced cutting or abrasive action. There is generally less local temperature rise near the working surface of the abrasive at the interface with the part being polished or polished, such that . The use of silicone rubbers or elastomers generally provides significantly more stable and longer lasting materials than organic polymers. However, there is still some surface friction, resulting in local temperature increases and build-up in the solid silicone rubber.

SUMMARY OF THE INVENTION Generally speaking, one object of the present invention is to provide an improved abrasive and polish material which solves or substantially eliminates the problems mentioned above and which has an essentially cellular structure. It is in.

Another object of the invention is to provide an abrasive material with improved surface friction properties.

Another object of the present invention is to provide a method for making an abrasive material with improved surface friction properties.

Yet another object of the invention is to provide an article made from an abrasive material with improved surface friction properties.

Another object of the present invention is to provide an abrasive material and method for making the same that has improved accessibility of abrasive grit on the surface of the abrasive material.

These and other objects of the present invention are accomplished by providing an organopolysiloxane foam having abrasive grit uniformly dispersed within the organopolysiloxane. Improved surface friction properties are achieved by providing voids or cells in the organopolysiloxane without sacrificing the integrity of the material itself. The combination of the properties and characteristics of the silicone rubber or elastomer and its void volume or cell morphology results in reduced surface friction and improved heat dissipation and consequent reduced thermal degradation.

This results in improved accessibility of the abrasive grit material at the surface. Additionally, the use of organopolysiloxane foams with abrasive grits uniformly dispersed within the organopolysiloxanes requires use at significantly higher service temperatures than solid silicone rubber or organic polymer foams or solid bodies. enable. Solid silicone rubber or elastomer demagnetizes higher frictional heat, thus resulting in shorter service life. The foamed organopolysiloxane elastomers of this invention are of course used at lower temperatures than solid silicone elastomers. Thus, the expanded organopolysiloxane elastomer of the present invention with abrasive grit uniformly distributed therein will have an extended service life compared to that of a solid organopolysiloxane containing abrasive grit. .

In accordance with at least some objects of the present invention, mixing an abrasive grit or polishing medium into an organopolysiloxane containing an organopolysiloxane foam former until the grit, etc. is substantially uniformly dispersed; There is further provided a method of making an abrasive material with improved surface friction properties comprising foaming the mixture; and curing the resulting photofoam. Further, in accordance with at least some aspects of the present invention, an organopolysiloxane containing an organopolysiloxane foam former and a catalyst and including an abrasive grit is inserted into a mold and heated to an elevated temperature to cure it. A method for producing a molded article is provided which comprises curing the organopolysiloxane. Accordingly, in certain embodiments of the invention, an organopolysiloxane containing an organopolysiloxane foam former and containing abrasive grit is heated in a mold to an elevated temperature in the presence of a catalyst, thereby filling the The gas formed in situ by the reaction of the agent and the components in the organopolysiloxane forms cells in the organopolysiloxane and simultaneously cures the organopolysiloxane from the abrasive foam material in a mold at high temperatures. An article is formed.

These and various other objects, features and advantages of the present invention will be better understood from the detailed disclosure below.

DETAILED DESCRIPTION OF THE INVENTION In the present invention, an abrasive material with improved surface friction properties is a spongy or foamed silicone elastomer or rubber binder or matrix material, i.e., a substantially uniformly dispersed abrasive material or It must have an organopolysiloxane foam or sponge containing a glaze material.

To accomplish at least some of the objects of the present invention, an organopolysiloxane foam or sponge rubber containing an abrasive or polish material dispersed within the organopolysiloxane material itself provides reduced surface friction. It should provide lower material temperatures with improved accessibility of the abrasive or polishing surface to the body being processed. Composites formed according to the present invention include an abrasive grit or polish material substantially uniformly dispersed within an organopolysiloxane foam such that the resulting cured composite abrasive material exhibits cellular structure characteristics. It must be such that it exhibits both abrasive properties and abrasive properties.

Organopolysiloxane foams are particularly amenable to molding into arbitrary shapes without the need for significant heat or pressure and are easy and inexpensive to handle during molding. In a preferred embodiment, the organopolysiloxane foam is high temperature curable, so that the organopolysiloxane containing the organopolysiloxane foam former can be easily handled, e.g., by charging it into a mold. Abrasive or polish materials and other additives can be substantially uniformly dispersed in the organopolysiloxane before curing.

The composition of the organopolysiloxane foam of the present invention has a desired cell size, i.e., from about 0.001 cm to about 0.30 cm.
cells ranging from about 15% to about 85% of the organopolysiloxane in the foam, more preferably from about 15% to about 25% of the organopolysiloxane in the foam; % porosity, toughness or hardness required for use in a particular operation, and heat resistance;
so as to provide a foamed binder or matrix material with desired basic properties, including receptivity to non-volatile fillers and receptivity to abrasive or polish materials to increase anti-friction properties, etc. can be carefully controlled.

Any organopolysiloxane material can be suitably foamed to provide an organopolysiloxane foam that can be used to make the abrasive materials of this invention. Representative organopolysiloxane foam forming materials and methods of formation and representative foamable organopolysiloxanes are well known in the art. An example of a representative loganopolysiloxane foam-forming material is U.S. Pat. No. 3,379,6.
Please refer to the specification of No. 59. U.S. Pat. No. 3,379,659 discloses room temperature vulcanizable organopolysiloxane foam-forming compositions and methods for making organopolysiloxane foams using silicon hydride and aminoxy-substituted organosilicone materials. is listed. Foaming in the process described in U.S. Pat. No. 3,379,659 is accomplished by liberating hydrogen gas from hydrogen silicon upon contacting the foam-forming composition with a hydroxyl compound such as atmospheric moisture. According to one preferred embodiment of the invention, a hydrated filler material, such as hydrated silica, is incorporated into the organopolysiloxane rubber or elastomer. Such hydrated silicas, etc., allow moisture to be liberated from the hydrated silica when heated to a suitable elevated temperature and simultaneously cure the composition in the presence of a catalyst to form a cured material. This moisture reacts with the cell forming agent in the organopolysiloxane elastomer to produce gas, which causes the organopolysiloxane rubber or elastomer to foam. This can be done in any mold that forms the desired molded part. In one molding method known in the art, a layer of fabric is placed between a surface plate and a side support wall of a mold. Another representative expandable organopolysiloxane composition, which facilitates the dissipation of blowing gases and can be easily adapted to molding techniques using low molding pressures, is described in U.S. Pat. No. 3,425,967. has been done. That is, the foamable composition described in U.S. Pat. No. 3,425,967 consists of a vinyl-terminated polysiloxane having a specific formula, (R'') 0.5 units of 3SiO and 2 units of SIO, about 2. an organopolysiloxane copolymer containing from 5 mole percent to about 10 mole percent silicon-bonded vinyl groups; a fibrous material; a fine filler; an amount of a liquid organohydrogen polysiloxane having a specific formula; and a blowing agent. It consists of

Yet another representative silicone foam is U.S. Pat.
No. 624,010, in which organopolysiloxane foams are prepared by mixing a carboxyalkylpolysiloxane, a diisocyanate, and a tertiary amine, foaming the composition, and then curing the foamed composition. Manufactured by U.S. Patent No. 3,624,
In the method described in the '010 specification, the carbon dioxide generated during the reaction of these components foams the product during the curing reaction, thus forming a foam. In the method described in U.S. Patent No. 3,624,010,
The product is heated to a temperature of about 100°C to about 120°C, thereby resulting in a cured, foam-like organopolysiloxane product.

Still other typical organopolysiloxane foams known in the art can also be used in the present invention. For example, other typical organopolysiloxane foams that may be used in the present invention are organopolysiloxanes cured with peroxides containing conventional blowing agents, such as benzesulfonyl hydrazide (BSH). Other conventional blowing agents include, for example, toluenesulfonylhydrazide (TSH), 4,4'-oxybis(benzenesulfonylhydrazide) (OBSH), and azobisformamide (ABTA), also known as azodicarbonamide. Sufficient heat is applied to simultaneously generate gas from the blowing agent and cause the rubber or elastomer being "foamed" to be destroyed by the action of the gas. Other typical organopolysiloxane foams are cross-cured organopolysiloxane rubbers or elastomers, such as in the presence of moisture, such as water contained in a water-containing filler dispersed within the organopolysiloxane material. It is a rubber or elastomer containing silicon hydride that releases hydrogen gas (a blowing agent). Here, the water in the water-containing filler is released when the organopolysiloxane containing the water-containing filler is heated to high temperatures. As indicated above, in this preferred embodiment, heating the organopolysiloxane rubber or elastomer to release water in the hydrated filler, such as water phase silica, simultaneously causes curing of the organopolysiloxane and During this heating, hydrogen gas is released and cells or voids are formed in the organopolysiloxane rubber or elastomer. Therefore, in a preferred embodiment of the invention,
Organopolysiloxane foams are high temperature curable. Such high temperature curable foams are formed by the formation of hydrogen on methyl hydrogen on a silicon hydride (methyl silicon hydride) crosslinker which is commercially acted upon by platinum. This is because not only does it affect curing, but it also affects foaming due to the release of hydration water contained in the filler in the organopolysiloquiline material. This water reacts with the silicon hydride incorporated in the organopolysiloxane rubber or elastomer to release hydrogen gas and form voids in the organopolysiloxane material. For example, if the organosiloxane photofoam is an organopolysiloxane that is addition cured and a typical addition cure or crosslinking agent, such as silicon hydride (
(e.g. methylhydrogen silicon), it is cured at elevated temperatures in the presence of an addition catalyst, preferably a typical platinum derivative catalyst well known in the art, and at the same time hydrogen gas is released to homogeneously disperse it. voids or cells are formed in the organopolysiloxane further containing the abrasive or polish material.

When the organopolysiloxane foam is formed from an addition-curing organopolysiloxane, the gas that forms the voids or cells in the organopolysiloxane is caused by the reaction between the filler and the substance contained in the organopolysiloxane. derived from.

For example, water-containing fillers, such as hydrated fillers such as hydrated silica, can be dispersed or incorporated into organopolysiloxanes as is well known in the art. Agents that are compatible with the organopolysiloxane and release gas in the presence of water can be incorporated into the organopolysiloxane by mixing. When the water in the filler is released, a gas is formed by reaction with the agent in the organopolysiloxane rubber or elastomer, which forms a gas in the presence of water, and this gas forms the organopolysiloxane. Cells or voids are formed therein. for example,
One typical agent that reacts with water to produce hydrogen gas is silicon hydride, such as methyl silicon hydride. Accordingly, in one preferred embodiment of the present invention, hydrated silica is incorporated into the organopolysiloxane rubber as a filler and silicon hydride is incorporated into the organopolysiloxane rubber as a crosslinking agent and hydrated at elevated temperatures. Hydration water is released from the silica and reacted with silicon hydride to generate hydrogen gas. The high temperature used in this case is approximately 50
℃ to about 200℃. Incorporating a typical catalyst, such as a platinum catalyst, causes the organopolysiloxane rubber to simultaneously cure while the hydrogen gas foams the organopolysiloxane rubber. Therefore, this high temperature must be sufficient to cause the water in the hydrated silica to react with the silicon hydride to liberate hydrogen, which causes the organopolysiloxane rubber to form internal cells and simultaneously harden. cause to occur.

The abrasive grit or polish material, generally referred to herein as an abrasive grit, can be any known abrasive or polish material. For example, silicon carbide, finely ground aluminum oxide, synthetic alumina, diamond, cubic boron nitride, synthetic mullite and their abrasive properties and/or
or other natural and synthetic materials whose polishing properties are generally known to those skilled in the art.

As mentioned above, in one preferred embodiment of the invention, an abrasive material comprising an organopolysiloxane foam containing abrasive grit uniformly dispersed in an organopolysiloxane is treated with an organosilane or equivalent agent. may assist in bonding the abrasive or polish material to the organopolysiloxane foam binder or matrix. According to the invention, preferred organosilanes are vinyltriethoxysilane, 2(3,4-epoxycyclohexyl)ethyltrimethoxysilane, phenyltriethoxysilane, methacryloxypropyltrimethoxysilane, gamma-aminopropyltriethoxysilane and aminosilane. Can be salicylamide. Methods and compositions for pretreating abrasive or polish materials prior to dispersion in organopolysiloxanes are disclosed in U.S. Pat.
No. 89,541 and No. 3,904,391. The disclosures of these U.S. patents, in summary, provide that the abrasive or polish material is treated with at least one particular organosilane, preferably after treatment with a suitable treatment agent such as an alkali metal hydroxide or other etchant. It is related to the method of cleaning. Processes for the treatment of abrasive or polish materials and solutions therefor are specified in detail in the above-mentioned patent documents.

The amount of abrasive grit or polish material incorporated into the organopolysiloxane foam is generally critical to avoid creating large island-like zones in the organopolysiloxane foam that do not contain abrasive grit. Therefore, a minimum amount must be incorporated into the organopolysiloxane foam to provide a sufficient amount of abrasive or polish material substantially uniformly dispersed within the organopolysiloxane. It's the amount. The maximum amount of abrasive or polish material is such that it does not destroy or damage the integrity of the organopolysiloxane foam rubber or elastomer in which it is uniformly dispersed. In most embodiments, the minimum amount necessary to avoid the formation of bands or islands of abrasive grit-free material is at least about 53 weight percent, based on the weight of the organopolysiloxane. In most embodiments, the abrasive or polish material is generally present in the organopolysiloxane foam rubber, based on the weight of the organopolysiloxane rubber.
It is incorporated in an amount in the range of about 80% by weight.

The abrasive grit or polish material must be substantially uniformly dispersed in the organopolysiloxane prior to foaming of the organopolysiloxane to provide improved surface friction properties. This is generally achieved by thoroughly mixing, blending or dispensing the abrasive grit or polish material into the organopolysiloxane rubber or elastomer prior to foaming of the organopolysiloxane rubber or elastomer and which other materials, This can be done at the same time as, for example, fillers, blowing agents such as organopolysiloxane foam formers, and gas formers such as silicon hydride are dispersed therein. The oreganopolysiloxane rubber or elastomer that is foamed is generally a rubber, although in some cases the organopolysiloxane can be a liquid. Although liquids can be utilized, it is more difficult to keep the abrasive grit or polish material uniformly dispersed within the organopolysiloxane liquid until it is cured. In any event, the abrasive grit or polish material and other materials, such as fillers and organopolysiloxane foam formers, are mixed in suitable mixing equipment,
Incorporated into the organopolysiloxane rubber or elastomer by thorough mixing using, for example, a Waring mixer, ball mill, rubber roll mill, Banbury mixer or any other suitable stirring or mixing equipment.

Various reinforcing fillers can also be incorporated into the organopolysiloxane foams of this invention. Inorganic filler for reinforcement,
For example, calcium carbon, titanium dioxide, silica, fumed silica, hydrated silica which provides water to react with silicon hydride to produce hydrogen gas for foaming as described above, kaolinite clay, aluminum silicate clay, silica, etc. Carbon black and the like can be added to obtain the desired results by those skilled in the art. Generally, reinforcing fillers or additives can be used alone or in combination;
These can serve to strengthen the organopolysiloxane matrix and increase the Shore hardness of the final product. The proportion of the abrasive grit or polish material can also be used to vary the hardness, and the abrasive or polish material can be added to achieve the desired hardness, as is well known to those skilled in the art, along with the desired polish or abrasive action. The respective amounts of material and reinforcing filler can be balanced. Generally, in accordance with the present invention, reinforcing fillers and other fillers can be used in amounts up to about 50% by weight of the organopolysiloxane.

Of course, as mentioned above, the organopolysiloxane of the present invention further contains an organopolysiloxane foam former. The foam-forming agent may be a gas or an agent that forms a gas in the presence of moisture, heat, chemical additives, etc., and combinations thereof. More specifically, the amount of foam forming agent in the organopolysiloxane of the present invention is about 85% of the total volume of the organopolysiloxane body to form the desired porosity or proportion of gas cells or voids in the foam. % of voids within the cellular structure. Generally, about 15% to about 85% of the total volume of the organopolysiloxane body is void volume, and more preferably about 15% to about 25% of the total volume of the organopolysiloxane constitutes gas cells or voids. Such void spaces can be in the form of substantially closed cells or generally continuous or interconnected cells. As mentioned above, bubbles or voids are generally created within the organopolysiloxane by the release of gas, such as by the release of hydrogen when a silicon hydride or hydrazide reacts with water, or by the release of hydrogen when a diisocyanate acting as a blowing agent reacts with heat. is formed by the release of carbon dioxide in the presence of carbon dioxide. In most cases, in preferred embodiments of the invention, the abrasive material, i.e., an organopolysiloxane foam containing an abrasive grit or polish material uniformly dispersed within the organopolysiloxane foam, weighs about 60 lbs. / cubic foot ~ about 95 pounds /
It has a density of cubic feet.

The porosity and cell size of the organopolysiloxane foams of this invention are controlled by the amount of foaming agent or other organopolysiloxane foam-forming material incorporated into the organopolysiloxane. Additionally, various types and amounts of surfactants and nonionic cell stabilizers may be used to control porosity and cell size. Generally, the higher the amount of surfactant or cell stabilizer, the finer and more uniform the cells will be. The porosity and cell size within the organopolysiloxane foam can also be controlled to some extent by the degree of material loading of the mold, ie, the amount of organopolysoloxane used or the loading of various fillers and additives. For example, a mold can be loaded with material to any degree of loading and, when sealed, expand by an amount corresponding to the unfilled portion of the mold. Control of porosity and cell size may therefore be related to the degree of mold filling, ie, the amount of organopolysiloxane material charged to the mold.

Generally, when producing abrasive materials with improved surface friction properties in accordance with the present invention, an abrasive or polish material is combined with an organopolysiloxane containing an organopolysiloxane foam former and an abrasive or polish material. Mix until the excipient material is substantially uniformly dispersed in the arganopolysiloxane. After mixing is thorough and all ingredients, including fillers, catalysts, foam formers, abrasive or polish materials, etc., are uniformly dispersed in the organopolysiloxane,
The mixture is foamed and cured. As mentioned above, curing can be accomplished simultaneously with foaming. The order in which fillers, foam formers, catalysts, and other optional materials are incorporated into the organopolysiloxane is not critical as long as they are uniformly dispersed in the organopolysiloxane by proper mixing.

Suitable catalysts such as organic peroxides, platinum or platinum derivatives and any other well known catalysts for organopolysiloxanes, organopolysiloxane foam formers, one or more crosslinking agents such as silicon hydrides, Catalytic organic amounts may be incorporated into the organopolysiloxane along with fillers, abrasives or polish materials, etc. Generally, the sample amount of catalyst can be easily adjusted by one skilled in the art by simple experimentation. The curing time can also be easily controlled by those skilled in the art depending on the desired degree of curing.

After the ingredients have been thoroughly mixed and the abrasive grit or polish material has been substantially uniformly dispersed throughout the organopolysiloxane rubber or elastomer, the organopolysiloxane foam containing the abrasive grit and the organopolysiloxane foam The mixture is foamed and cured by heating the organopolysiloxane rubber or elastomer containing the former to an elevated temperature in the presence of a catalytic amount of catalyst effective to cure the organopolysiloxane. Often this elevated temperature will be from about 50°C to about 300°C, more preferably from about 150°C to about 2°C.
It is 00℃. The heating time is the time required to achieve the desired cure and can be, for example, from about 1 minute or less to 5 hours or more. After curing is complete, the cured foam containing the abrasive grit or polish material is cooled to room temperature, usually in the mold, and removed from the mold.

In general, organopolysiloxane foams containing abrasive grit or polish materials uniformly dispersed within the organopolysiloxane can be molded or formed into virtually any desired shape and size. Molded abrasive and polish articles such as magnetic wheels and puff wheels are well known. Organopolysiloxane foam belts and sheets containing homogeneously dispersed abrasive grit or polish materials can also be made from the materials of this invention, and these can be fibrous or non-fibrous. The orgal polysiloxane foam containing uniformly distributed abrasive grit according to the present invention, which can be formed on a backing material line or reinforcing material, can be formed into a continuous belt or sheet according to standard methods. .

When formed into abrasive or polish articles such as those described above, the flexible, cellular organopolysiloxane foams of the present invention may be suitably reinforced with fibers, fabrics, and the like. Generally, improved grit surface accessibility is obtained, giving more aggressive or greater grinding power and shorter grinding or polishing times.

In one preferred embodiment of the invention, the molded article incorporates an abrasive grit or polish material into an organopolysiloxane rubber or liquid containing an organopolysiloxane foam former such that the abrasive grit is substantially uniformly dispersed in the organopolysiloxane rubber or liquid containing the organopolysiloxane foam former. mixing until dispersed, charging the mixture into a mold, the mixture containing a crosslinking agent and a catalyst to promote crosslinking or curing of the mixture, foaming the mixture and curing the foam. formed by The mixture may be heated to an elevated temperature in the mold as desired to promote foaming and/or curing of the organopolysiloxane rubber or elastomer. Of course, if the organopolysiloxane foam former is a hydrogen silicon that reacts with water from one or more water-containing fillers in the organopolysiloxane,
Cells are formed in the organopolysiloxane rubber or elastomer by releasing hydrogen gas when the mixture is heated to an elevated temperature, usually in the range of about 150°C to about 200°C.

Next, the present invention will be further explained by examples, but these are merely for illustrative purposes and are not intended to limit the present invention in any way.

Example 1 A silicone rubber bound containing hydrated silica as a reinforcing filler was foamed by mixing with methyl hydride silicon oil and a platinum catalyst.

The silicone rubber is 68.8 parts by weight of polydimethylmethylvinylsiloxane, 29 parts by weight of hydrated silica,
1.9 parts by weight of silanol-terminated polydimethylsiloxane liquid, 0.9 parts by weight of vinyltris(2-ethoxymethoxy)silane.
4 parts by weight and 0.1 part by weight of a typical heat aging additive. The resulting composition contained 47 parts by weight of the reinforced organopolysiloxane described above, 53 parts by weight of a #60 grit particle size silicon carbide abrasive material, 1 part by weight of methyl silicon hydride oil, and 1 part by weight of platinum catalyst. .

These ingredients were homogeneously mixed in a conventional rubber roll mill so that the abrasive grit was evenly distributed throughout the mixture, and the mixture thus prepared in a rubber roll mill was mixed at 1.
A 6 inch by 6 inch by 0.5 inch mold was charged. The mold was not filled to capacity, leaving room for expansion due to the release of hydrogen gas. At high molding temperatures,
The hydrogenated merium reacted with the water contained in the aqueous phase silica filler to liberate hydrogen gas, thus forming air bubbles in the siloxane rubber. Prior to charging the mixture into the mold, an open bedding cloth was charged into the mold to facilitate the foaming operation by aiding the distribution of hydrogen gas. The mold was heated to about 177°C for about 20 minutes. Slabs of expanded organopolysiloxane containing silicon carbide abrasive grit have a specific gravity of 1.66 compared to 1.66 for a comparative unfoamed organopolysiloxane containing the same dimensions and the same amount of silicon carbide abrasive grit. It had a specific gravity of 42. The foamed organopolysiloxane containing silicon carbide abrasive had a pro ratio of 1.17. The polishing action of this composition was good, and the wear resistance of the slab composition was subjectively evaluated to be good.

The abrasive action is based on the foam composite diameter of 5.03 cm (2 inches).
x 1.27 cm (0.5 inch) thick disk coupons were mounted on a tabletop electric drill and tested for properties by using them to polish various metal surfaces. This composite material exhibited good abrasive and body abrasion properties.

Example II A silicone compound loaded with fumed silica as a reinforcing filler was foamed by mixing with a blowing agent, an organic peroxide catalyst, and an abrasive grit. The silicone rubber is 70.5 parts by weight polydimethylmethylvinylsiloxane, 1.0 parts by weight of typical heat aging and compression set additives, 5.4 parts by weight of diatomaceous earth, and pretreated fumes. 19.5 parts by weight of dosilica,
It contained 0.2 parts by weight vinyltriethoxysilane and 3.4 parts by weight methoxy-terminated polydimethylsiloxane liquid. The resulting composition contained 47 parts by weight of the fumed silica-reinforced silicone rubber, 53 parts by weight of 80 mesh silicon carbide abrasive material, and 0 parts by weight of benzenesulfonyl hydrazide foam material.
．． 4 parts by weight, 0.8 parts by weight of 2,4-dichlorobenzoyl peroxide and Vcrox powder (2,
5-dimethyl-2,5-bis(t-butylperoxy)
2 parts by weight of 50% hexane. This composition was mixed and molded as described in Example 1. The foamed, cured organopolysiloxane slab containing the silicon carbide abrasive had a specific gravity of 1.24 compared to 1.66 for the comparative unfoamed organopolysiloxane. The blow ratio of the foamed organopolysiloxane containing silicon carbide abrasive was 1.34. The abrasive action of this composition was excellent.

Although the present invention has been described above with reference to specific embodiments, various other embodiments and modifications thereof that are not exemplified can also be used in the present invention, and the present invention encompasses the techniques shown in the claims. It includes various such embodiments within the scope of the concept.

Uneral 1 - Rector Cumber - (Agent (7)
630) raw i1'f love two

Claims (1)

[Claims] 1. An abrasive with improved surface abrasion properties consisting of an organopolysiloxane foam containing abrasive grit uniformly dispersed in an organopolysiloxane. 2. The abrasive material according to claim 1, wherein the organopolysiloxane foam is curable at high temperatures. 3. 2. The abrasive material of claim 1, wherein the organopolysiloxane foam is an addition-cured organopolysiloxane cured at high temperature in the presence of a catalyst. 4. Scope 3 of the patent claim wherein the high temperature used for curing the organopolysiloxane is from about 50°C to about 300°C.
Abrasive material as described in section. 5. 4. The abrasive of claim 3, wherein the elevated temperature used to cure the organopolysiloxane is from about 150<0>C to about 200<0>C. 6. 4. The abrasive material of claim 3, wherein the addition-cured organopolysiloxane is a hydrated silica-filled organopolysiloxane containing silicon hydride. 7. The high temperature used is high enough to liberate hydrogen when the water in the aqueous silica reacts with the silicon hydride, thereby causing the hydrogen to form cells within the organopolysiloxane and the hydrogen forming the organopolysiloxane. The abrasive material according to claim 6, which forms a siloxane foam. 8. 2. The abrasive material according to claim 1, wherein the organopolysiloxane foam is an organopolysiloxane cured with an organic peroxide and foamed with a blowing agent. 9. 2. The abrasive material of claim 1, wherein the organopolysiloxane foam is formed from (a) an organopolysiloxane containing an aqueous phase filler and (b) silicon hydride. 10. organopolysiloxane and silicon hydride at high temperature,
That is, the silicon hydride is cured at a temperature sufficient to liberate hydrogen gas by reaction with the water in the aqueous phase filler, such that the hydrogen gas forms cells in the organopolysiloxane during cure. Abrasive material according to item 9. 11. The pore space in the organopolysiloxane foam containing the abrasive grit is about 0.001 cm to about 0.30 cm.
The abrasive material according to claim 1, wherein the abrasive material is a cell having a size of . 12. 2. The abrasive of claim 1, wherein the organopolysiloxane foam containing abrasive grit has a density of from about 60 pounds per cubic foot to about 95 pounds per cubic foot. 13. Mixing abrasive grit into an organopolysiloxane containing organopolysiloxane foam forming material until the abrasive grit is substantially uniformly dispersed, foaming the mixture, and curing the foam. A method of manufacturing an abrasive material comprising: 14. The preparation of claim 13 in which a mixture of organopolysiloxane and abrasive grit containing an organopolysiloxane foam former is heated to an elevated temperature in the presence of a catalyst to cause foaming and cure the organopolysiloxane. Law. 15. 15. The method of claim 14, wherein the organopolysiloxane containing the organopolysiloxane foam former is heated to a temperature of about 50<0>C to about 300<0>C. 16. 15. The method of claim 14, wherein the organopolysiloxane containing the arganopolysiloxane foam former is heated to a temperature of about 150<0>C to about 200<0>C. 17. 15. The method of claim 14, wherein the organopolysiloxane is an organopolysiloxane containing a hydrated silica filler and silicon hydride. 18. The organopolysiloxane foam forming agent is silicon hydride and water in a hydrated silica filler and the silicon hydride and water are reacted at high temperature to release hydrogen gas thereby forming cells in the organopolysiloxane. Claim 1, in which an organopolysiloxane containing an abrasive grit dispersed therein is fired.
The manufacturing method described in Section 7. 19. Claim 18: Organopolysiloxane is simultaneously foamed and cured at high temperature in the presence of a platinum catalyst.
Manufacturing method described in section. 20. Approximately 10 based on the weight of organopolysiloxane
14. The method of claim 13, wherein from % to about 70% by weight abrasive grit is incorporated into the organopolysiloxane. 21. The cells formed in the organopolysiloxane containing the abrasive grit are from about 0.001 cm to about 0.30 cm.
14. A method according to claim 13 having dimensions in the cm range. 22. 14. The method of claim 13, wherein the organopolysiloxane foam containing abrasive grit has a density of from about 60 pounds per cubic foot to about 95 pounds per cubic foot. 23. An article formed by charging a mixture of an organopolysiloxane and abrasive grit containing an organopolysiloxane foam former and a catalyst into a mold and heating to an elevated temperature to foam and cure the organopolysiloxane. 24. An article formed by the method of claim 23, wherein the organopolysiloxane is an organopolysiloxane containing silicon hydride and containing a hydrated silica filler. 25. The organopolysiloxane foam forming agent is hydrogenated silicon and water in the hydrated silica filler and the water-blocking silicon and water are reacted in a mold at high temperature to form cells in the organopolysiloxane. 25. An article formed by the method of claim 24, wherein the organopolysiloxane is foamed and has abrasive grit dispersed therein. 26. 26. An article formed by the method of claim 25, wherein the organopolysiloxane is simultaneously foamed and cured in a mold at elevated temperatures. 27. 27. An article formed by the method of claim 26, wherein the heating temperature of the mold is from about 50<0>C to about 300<0>C. 28. 27. An article formed by the method of claim 26, wherein the heating temperature of the mold is about 150<0>C to 200<0>C.