JPH0624699B2 - Synthetic resin abrasive - Google Patents

Description

The present invention relates to a synthetic resin abrasive. More specifically, it relates to an abrasive comprising an unsaturated polyester resin obtained by suspension polymerization in an aqueous medium.

[Prior art and its problems]

Burrs occur during molding of semiconductor molded products such as ICs and LSIs (hereinafter simply referred to as molded products), but these resin burrs are usually removed by blasting / polishing by a dry method or a wet method. .

For blasting abrasives, hard abrasives composed mainly of inorganic materials such as alumina, silicon carbide, glass beads, soft abrasives composed of natural organic materials such as walnut shell powder, wood powder, and various synthetic resins are roughly crushed. There is an abrasive made of synthetic resin of polygonal powder obtained by the above.

Thus, among the above-mentioned various abrasives, the synthetic resin abrasive has an appropriate hardness, so that the synthetic resin abrasive is often used as the blasting abrasive for the molded product.

However, when this synthetic resin abrasive is used as the abrasive for the molded product, the following problems still remain.

That is, since the synthetic resin abrasive is obtained by coarsely crushing the hardened synthetic resin as described above, it has a polygonal shape and a large number of sharp-angled projections.

Therefore, if blasting and polishing is performed using an abrasive material of such a shape, a large number of sharp-angled protrusions adhere to the molded product due to the impact force when it is sprayed onto the semiconductor molded product at high speed. Therefore, there is a problem that the appearance of the product is impaired. Further, the above-mentioned acute-angled projections of the abrasive are fragile as they are understood from the shape when sprayed onto the molded product, and therefore the abrasive becomes early small particles, and the initial polishing ability cannot be maintained. It is necessary to replenish the abrasive with a new material within a short period of time, and in the worst case, the abrasive must be completely renewed.

Further, since the abrasive has a shape having a large number of acute-angled protrusions as described above, the resistance due to the friction between the particles of the abrasive is large. Therefore, during wet polishing, the abrasive is slurried with water to form a slurry. There is also a problem that when high-speed injection is carried out on a molded product, a clogging phenomenon of an abrasive, called packing, easily occurs in a pipe or at the bottom of a water slurry tank, and the efficiency of the polishing operation is significantly impaired.

[Means for solving problems]

As a result of intensive studies conducted by the present inventors to solve the above-mentioned problems, a specific synthetic resin obtained by a specific method as a blasting abrasive for molded products, particularly as a wet blasting abrasive It was found that the use of the above can maintain the polishing power superior to the conventional synthetic resin abrasives for a long period of time without impairing the aesthetics of the molded product, and completed the present invention. .

That is, the present invention provides a novel synthetic resin abrasive comprising an unsaturated polyester resin obtained by suspension polymerization in an aqueous medium.

[Specific conditions for carrying out the invention]

 Hereinafter, the present invention will be described in detail.

The object to be polished, which is intended for the abrasive of the present invention, is mainly a semiconductor mold-molded article as described above. However, most of the synthetic resins used for molding are epoxy resins. Therefore, in order to remove the burr of the epoxy resin-based molded product by blasting and polishing, especially by wet method, the hardness of the abrasive must correspond to the hardness of the epoxy resin, and The polishing performance must also be excellent. Further, it is preferable that the abrasive is not easily powdered.

According to the research conducted by the present inventors, such an abrasive is most preferably an unsaturated polyester resin obtained by suspension polymerization in an aqueous medium.

The abrasive of the present invention can be usually obtained by the following method. That is, first, an unsaturated dibasic acid and a glycol compound are subjected to an esterification reaction to form an unsaturated polyester, and this and a polymerizable vinyl monomer are subjected to suspension polymerization in an aqueous medium in the presence of a polymerization initiator to give spherical particles. Since a slurry containing the unsaturated polyester resin is obtained, the abrasive of the present invention can be obtained by passing the slurry through a centrifuge or the like. It should be noted that since this abrasive has moisture attached to it until it is passed, it must be dried when used as a dry abrasive. Further, this abrasive may be used by adjusting the particle size by a method such as sieving.

In the present invention, as described above, it is first necessary to produce an unsaturated polyester from an unsaturated dibasic acid and a glycol compound. The unsaturated dibasic acid is preferably, for example, maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, α, β-unsaturated dibasic acid such as chlorinated maleic acid, and one or more of them are used. .

Further, phthalic anhydride, isophthalic acid, terephthalic acid, monochlorophthalic acid, dichlorophthalic acid, trichlorophthalic acid, hettic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, endomethylenetetrahydrophthalic anhydride to the above unsaturated dibasic acid, Adipic acid, succinic acid,
It does not matter at all to add an appropriate amount of a saturated dibasic acid such as sebacic acid, glutaric acid or pimelic acid.

On the other hand, as glycol compounds, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,3
Butylene glycol, 2,3 butylene glycol, 1,4 butylene glycol, neopentyl glycol, hexylene glycol, octylene glycol, bisphenol A
Dioxyethyl ether adduct, bisphenol A dioxypropyl ether adduct, hydrogenated bisphenol A,
Alternatively, alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide are preferable, and polyhydric alcohols such as trimethylolpropane and glycerin may be used in combination, if necessary.

The esterification reaction of the unsaturated dibasic acid and the glycol compound is usually carried out by a known method.

Next, a polymerizable vinyl monomer and an appropriate amount of a polymerization initiator are added to this unsaturated polyester and mixed sufficiently, and then this is added dropwise to a sufficiently stirred aqueous medium to carry out suspension polymerization.

Examples of the polymerizable vinyl monomer that can be used in the present invention include styrene, α-methylstyrene, vinyltoluene,
Examples thereof include diallyl phthalate, vinyl acetate, methyl methacrylate, glycidyl methacrylate and the like.

In the present invention, the ratio of both of the unsaturated polyester and the polymerizable vinyl monomer in the suspension polymerization is significantly limited depending on the type of the unsaturated polyester and the polymerizable vinyl monomer or the required performance of the abrasive, and thus is not particularly limited. No, but usually 10 to 150 parts by weight of polymerizable vinyl monomer, based on 100 parts by weight of unsaturated polyester,
It is preferably 20 to 100 parts by weight.

In the present invention, the polymerization initiator is an organic peroxide such as methyl ethyl ketone peroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, t-butyl peroxide, azobisisobutyronitrile, azobis (2,4- Known compounds such as azo compounds such as dimethyl valeronitrile), water-soluble peroxides such as hydrogen peroxide, potassium persulfate and the like are used. The amount of the unsaturated dibasic acid as the raw material, the type of the glycol compound and the polymerizable vinyl monomer, and slightly different depending on the polymerization conditions, etc., 0.1 per 100 parts by weight of the total amount of each raw material
-10 parts by weight is preferred.

If necessary, 0.1 to 2.0 parts by weight of a curing accelerator such as cobalt naphthenate, N, N'-dimethylaniline, or cobalt octenoate may be added to 100 parts by weight of each of the above raw materials. .

In the present invention, the aqueous medium may be water itself, but a suspension stabilizer added in an appropriate amount for preventing deformation of particles during polymerization of the suspension polymer, excessive growth, or secondary aggregation of particles. preferable.

The suspension stabilizer is not particularly limited, and known ones can be used. That is, for example, water-soluble polymer substances such as polyvinyl alcohol, methyl cellulose, hydroxy cellulose, polyacrylic acid, water-insoluble inorganic salts such as magnesium oxide and calcium phosphate, surface active agents such as sodium alkylbenzene sulfonate and polyoxyethylene nonyl phenyl ether. The agents and the like are used alone or in combination. The addition amount varies depending on the type of the raw material, the conditions of polymerization, etc., but is preferably in the range of 1.0 to 30 parts by weight based on 100 parts by weight of the total amount of the raw materials.

The reaction temperature, reaction time, stirring conditions of the aqueous medium, etc. during suspension polymerization in the present invention are appropriately selected depending on the kind and amount of the raw materials, the particle size of the desired polymer, etc., but are generally known methods. Will be implemented. For example, the polymerization temperature varies depending on the type and amount of the polymerization initiator added, but is usually in the range of about 20 to 100 ° C, preferably 60 to 90 ° C, and the polymerization time is usually about 2 to 2 ° C.
It is employed for 0 hours, preferably for 4 to 15 hours.

Further, the polymerization is preferably carried out while stirring the aqueous medium in a state of being sealed in an atmosphere of an inert gas such as nitrogen or carbon dioxide as in the case of general suspension polymerization.

The shape of the unsaturated polyester resin of the present invention obtained by suspension polymerization is a fine spherical shape, but the particle size and particle size distribution are such that the type and amount of the suspension stabilizer to be added, the stirring speed, the unsaturated polyester It can be adjusted to some extent by a method of adding a mixed liquid of the polymerizable vinyl monomer and the polymerizable vinyl monomer.

Further, in the present invention, for the purpose of enhancing the polishing power of the abrasive,
When the unsaturated polyester and the polymerizable vinyl monomer are polymerized, an appropriate amount of inorganic filler can be added to this.

As the inorganic filler, any one can be used as long as it can enhance the polishing power of the abrasive, but usually, silicic acid anhydride, titanium oxide, zirconium oxide, calcium carbonate, clay, asbestos, talc, glass. Beads and the like are preferably used.

The addition amount of the inorganic filler is appropriately 5 to 100 parts by weight based on 100 parts by weight of the total amount of the unsaturated polyester and the polymerizable vinyl monomer. If the addition amount is less than 5 parts by weight, the effect of enhancing the polishing force is small, and if it is more than 100 parts by weight, the abrasive tends to be broken during polishing, which not only increases the tendency of the abrasive to become finer but also during polishing. This is not preferable because it may damage the object to be polished.

Further, when adding an inorganic filler, if necessary, a dispersant,
Antistatic agent, regardless of addition of anti-settling agent, various coupling agents, or addition of inorganic filler,
It is also possible to add a surfactant or the like to the mixture of unsaturated polyester and polymerizable vinyl monomer.

In the present invention, the particle size of the unsaturated polyester resin abrasive produced by suspension polymerization is, when used for removing resin burrs of a molded product, the polishing force of the abrasive and the lead frame of the molded product. From the relationship with the distance between pins 0.05 ~
A range of 1.0 mm is suitable.

〔The invention's effect〕

As described in detail above, the present invention is produced by subjecting an unsaturated polyester and a polymerizable vinyl monomer to suspension polymerization in an aqueous medium. The polishing power is superior to conventional abrasives obtained by coarsely crushing unsaturated polyester resin by several steps.

Furthermore, since the particles have a spherical shape, and the hardness of the unsaturated polyester resin is a hardness suitable for blasting and polishing the epoxy resin encapsulating the semiconductor,
Even if this abrasive is sprayed onto a molded product at high speed, the impact force causes the sharp protruding parts of the particles to fall off and adhere to the molded resin, resulting in a beautiful appearance, as with conventional abrasives made from crushed products. There is no problem if it is damaged or the surface of the molding material is damaged to adversely affect the reliability of the semiconductor device.

Further, since the abrasive of the present invention is spherical, the above-mentioned acute-angled projections do not fall off, so that even if the abrasive is continuously sprayed at high speed on the molded article, the particles are not reduced in size early. This means that the initial polishing force, which is several steps better than conventional products, can be maintained over a long period of time, so new abrasives can be replenished or the total amount can be reduced within a short period of time as in the past. The inconvenient situation of updating can be avoided.

Further, when the abrasive of the present invention is used, the shape thereof is spherical and the polishing power is superior to that of the conventional abrasive by several points. Therefore, the conventional abrasive has problems such as piping. Since the clogging and the packing phenomenon in the water slurry tank can be greatly reduced, the productivity of blasting and polishing can be greatly improved, and the injection pressure at the time of blasting can be made extremely low.

Furthermore, in the conventional method, for example, an unsaturated polyester resin abrasive is obtained by coarsely crushing a lump obtained by polymerizing and solidifying an unsaturated polyester and a polymerizable vinyl monomer,
Since the abrasive of the present invention is a method of suspension-polymerizing an unsaturated polyester and a polymerizable vinyl monomer as described above, it is possible to produce it continuously instead of batchwise, and the productivity is extremely improved. Can be made. Also, of course, no grinding is required.

As described above, the present invention has many advantages in both the production of the abrasive and the polishing, and the economic effect thereof is extremely great.

Further, it should be noted that the abrasive of the present invention is not limited only to polishing a molded product by wet blasting, and exhibits excellent polishing ability even when used for surface polishing of metal and the like. Furthermore, the abrasive of the present invention is not limited to the wet blast method, and is excellent as an abrasive for a dry blast method, a barrel method, or the like.

[Examples and Comparative Examples]

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, all parts are parts by weight.

Example 1. Isophthalic acid and maleic anhydride were used as dibasic acids, respectively 1.
5 mol, 3.0 mol, and propylene glycol and ethylene glycol as glycol compounds were mixed in the proportions of 3.5 mol and 1.45 mol, respectively, and the unsaturated polyester I was subjected to an esterification reaction at a temperature of 180 to 210 ° C. under a nitrogen atmosphere. Got Next, 100 parts of this unsaturated polyester I is dissolved in 50 parts of styrene monomer to make a viscous mixture, and 1.5 parts of azobisisobutyronitrile as a polymerization initiator is further added to this mixture and mixed again to obtain a uniform mixture. A liquid was obtained.
An aqueous solution prepared by dissolving 1.5 parts of polyvinyl alcohol (PVA-217s manufactured by Kuraray Co., Ltd.) as a suspension stabilizer in 450 parts of ion-exchanged water was used as an aqueous medium, and in this stirred aqueous medium,
A uniform mixed solution to which the above-mentioned polymerization initiator was added was added dropwise and dispersed as droplets, and suspension polymerization was carried out at 70 ° C for 3 hours and then at 85 ° C for 2 hours. After the completion of the polymerization, the slurry containing the produced unsaturated polyester resin particles is separated with a small centrifuge, washed with water, and then dried at 80 ° C. for 5 hours to form an abrasive containing transparent pearl particles having an average particle diameter of 210 μ. Got I.

Example 2. Isophthalic acid and maleic anhydride were used as dibasic acids, respectively 3.
0 mol, 1.5 mol, propylene glycol and ethylene glycol as a glycol compound were mixed at a ratio of 3.5 mol and 1.45 mol, respectively, and an esterification reaction was carried out in the same manner as in Example 1 to obtain an unsaturated polyester II. This unsaturated polyester II is dissolved in an equal weight of styrene monomer,
A viscous mixture was obtained. To 150 parts of this mixed solution, 1.5 parts of lauroyl peroxide as a polymerization initiator was added and mixed again to obtain a uniform mixed solution. Example 1 below. Suspension polymerization was carried out in the same manner as in 1. to obtain an abrasive II comprising transparent pearl particles having an average particle diameter of 190μ.

Example 3. Example 1. A viscous mixture of unsaturated polyester I and styrene monomer obtained in the same manner as in (the mixing ratio of unsaturated polyester and styrene monomer is the same as in Example 1) 80
In advance, hollow ceramic beads having an outer diameter of 0.5 to 20 μ (manufactured by Maruwa Biochemical Co., Ltd., Geospheres: Zeeo)
spheres) is hydrolyzed with an aqueous solution of a silane coupling agent (A-174 manufactured by Nippon Unicar Co., Ltd.) and a titanium coupling agent (KR-46B manufactured by Ajinomoto Co., Inc.), and then dried. 20 parts was added and uniformly mixed and dispersed. Next, azobisisobutyronitrile as a polymerization initiator was added to the viscous liquid mixture containing the inorganic filler.
8 parts was added and mixed again homogeneously. After degassing this mixed solution under a vacuum of 20 Torr for 10 minutes, the mixture was added dropwise to an aqueous medium composed of an aqueous solution containing a small amount of polyvinyl alcohol as in Example 1 and suspended under the same conditions as in Example 1. After polymerization, the product was filtered, washed with water, and dried to obtain an abrasive III including black-gray pearl-like particles having an average particle size of 220 μm.

Example 4 A viscous mixture of unsaturated polyester I and styrene monomer obtained in the same manner as in Example 1 (unsaturated polyester I
The mixing ratio of styrene monomer and styrene monomer is the same as in Example 1), and 50 parts of fused alumina particles for rough finishing having a particle size of 5 to 50 μm in advance are used as titanium coupling agents (KB-46B manufactured by Ajinomoto Co., Inc.).
After the hydrolysis treatment with 50 parts, 50 parts of an inorganic filler formed by drying was added and uniformly dispersed. Next, 0.5 part of lauroyl peroxide as a polymerization initiator was added to this viscous mixed liquid containing an inorganic filler, and the mixture was uniformly mixed again. An aqueous solution prepared by dissolving 2.0 parts of carboxymethyl cellulose (PL-15 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a suspension stabilizer in 200 parts of ion-exchanged water was used as an aqueous medium, and the above polymerization was initiated in the stirred aqueous medium. The homogeneous mixed solution to which the agent was added was added dropwise, dispersed as droplets, and suspension polymerization was carried out at 80 ° C. for 5 hours. After completion of the polymerization, the same post-treatment as in Example 1 was carried out to obtain an abrasive VII composed of black-gray pearl particles having an average particle diameter of 550 μm.

Example 5 Abrasive VIII was obtained in the same manner as in Example 4 except that the fused alumina particles for rough finish used in Example 4 were replaced with fused alumina particles for gloss finish having a particle size of 1 to 5 μm. It was This abrasive VIII was white pearl-like particles having an average particle size of 500μ.

Comparative Example 1. Unsaturated polyester I identical to that obtained in Example 1
Viscous mixture of styrene monomer and styrene monomer (mixing ratio of unsaturated polyester I and styrene monomer is the same as in Example 1)
To 100 parts, 0.3 part of a 6 wt% cobalt naphthenate aqueous solution as a curing accelerator was added, and 1.0 part of methyl ethyl ketone peroxide as a polymerization initiator was added, and then mixed uniformly.
Then, the homogeneous mixed solution was left standing on a stainless steel tray for 20 hours to be cured, and then heated at 80 ° C. for 3 hours to be recured. Then, the obtained unsaturated polyester resin cured product was crushed by a roll crusher and an atomizer to obtain an abrasive IV.

Comparative example 2. A viscous mixture of unsaturated polyester II and styrene monomer identical to that obtained in Example 2 (unsaturated polyester
The mixing ratio of II and styrene monomer was the same as in Example 2), and the mixed solution was cured and pulverized in the same manner as in Comparative Example 1 to obtain an abrasive V.

Comparative Example 3. The same viscous mixture of unsaturated polyester I and styrene monomer obtained in Example 3 (the mixing ratio of unsaturated polyester I and styrene monomer is also the same as in Example 3) 80
To 20 parts, 20 parts of an inorganic filler composed of hollow ceramic beads treated with a coupling agent as in Example 3 was added and uniformly mixed and dispersed. Then, as in Example 3, a polymerization initiator was added to this viscous mixed solution containing an inorganic filler, and the mixture was mixed well and then degassed in vacuum. Next, this vacuum-degassed mixed solution was hardened and pulverized in the same manner as in Comparative Example 1 to obtain an abrasive VI.

Comparative Example 4 A viscous mixed solution (in which the brand used and the amount added are all the same as those in Example 4) obtained by adding the inorganic filler and the polymerization initiator, which was obtained by the same method as in Example 4, was prepared in advance. After casting into a silicone rubber mold coated with, this mold was placed in a dryer at 85 ° C. and polymerization was carried out for 5 hours. Then, this mold was taken out from the dryer and cooled, and then the polymerized molded product was released from the mold to obtain a conical abrasive IX having a bottom diameter of 10 mm and a height of 10 mm.

Comparative Example 5 Abrasive X was obtained in the same manner as in Comparative Example 4 except that the rough-finished fused alumina particles used in Comparative Example 4 were replaced with gloss-finished fused alumina particles having a particle diameter of 1 to 5 μm. .

Test Examples 1-6. Using the abrasives obtained in Examples 1 to 3 and Comparative Examples 1 to 3, a wet blast polishing test was performed to evaluate the performance of each abrasive. In order to facilitate comparison of evaluations, each abrasive was sized by sieving, and particles having a particle size of 150 to 250 μm were prepared and subjected to the test. The wet blast test was performed using a liquid honing machine (LH-5 type) manufactured by Fuji Seiki Co., Ltd.

The test method is as follows. That is, each abrasive was slurried with water and the slurry concentration was adjusted to 30% by weight.
The acrylic resin plate was first blasted for 1 minute at a projection pressure of 4 kg / cm ² G and a projection distance of 5 cm, and the weight reduction amount of the acrylic resin plate was taken as the initial polishing amount. Next, after using a tin plate and blasting at the same pressure and distance as above for 1 hour, the acrylic resin plate was blasted again for 1 minute. Blasting of the acrylic resin plate and the tin plate was alternately repeated to measure the change with time of the polishing amount of the acrylic resin plate. Next, the polishing amount of the acrylic resin plate is 1 / the initial polishing amount.
The time until reaching 2 was measured, and this time was defined as the usable time of the abrasive.

The results are shown in Table-1.

Further, in the blast polishing, a part of the abrasive slurry was sampled every 5 to 10 hours, wet-classified using a JIS sieve having an opening of 149μ, and the ratio of fine particles under the sieve was measured to obtain the fine powder generation rate. did.

The results are shown in Table-2.

Moreover, the state of destruction of the generated fine powder was observed with a microscope.

The outline is shown in Table-3.

Separately, new abrasives I to VI were used to perform wet blasting of unpolished IC-sealed mold-molded products to observe resin burr removal performance and stain roughness on the surface of the molding material. The polishing method was as follows. That is, the slurry concentration of each polishing material was 30% by weight, the projection pressure was 4 kg / cm ² G, the projection distance was 5 cm, and the polishing time was 1 IC-molded product.
It took 2 seconds per chip. The polishing results were evaluated on a scale of 10, with 10 being the best, 5 being practically acceptable, and 1 being the worst. The results are shown in Table-4.

Test Examples 7 and 8 Barrel polishing tests were performed using the abrasives VII and IX obtained in Example 4 and Comparative Example 4, and the rough finishing performance of each abrasive was evaluated.

The barrel polishing test was performed using a small centrifugal barrel polishing machine (Denko Auto Picker). The test method is as follows. That is, one of two centrifugal barrel vessels with a volume of one
Abrasive VII was sized by sieving and adjusted to a particle size of 250-1000μ and weighed 700 g, and 100 g of abrasive IX, 693 g of water and compound 7 g of KC manufactured by Co., Ltd. was charged.

Next, weighed 20 mm in width, 50 mm in length and 2 in width.
mm SUS304 flat plate (JIS G4 manufactured by Nippon Test Panel Industry Co., Ltd.)
305) test piece and an aluminum plate of the same size and shape (JIS H4 manufactured by Japan Test Panel Industry Co., Ltd.)
Each of the test pieces of (000) was placed in each of two containers and rotated at a speed of 280 rpm for 60 minutes. Next, after taking out the test pieces of SUS304 and aluminum from the container, each test piece was washed with water and dried, and then the weight of each test piece was measured. The difference between the weight of the test piece before being subjected to the polishing test and the weight of the test piece after polishing for 60 minutes was defined as the initial grinding amount.

Next, each test piece whose weight was measured was charged again into the original container of the centrifugal barrel polishing machine, and polishing was performed under the same conditions and operations as above, and the second polishing test was performed. After completion of the second polishing test, the test pieces were similarly washed with water and dried, and the weight of each test piece was measured. The difference between the weight of the test piece before being subjected to the second polishing test and the weight of the test piece after the second polishing test was defined as the secondary grinding amount.

Similarly, a third polishing test was performed to measure the amount of tertiary grinding.
In this way, the grinding amount per unit time was measured. The results are shown in Table-5.

In addition, the degree of scratches and gloss on the surface of each test piece after the completion of the third polishing test was observed.

Further, open each abrasive after opening the third polishing test 250
It was wet washed with water using a JIS JIS sieve. After washing with water, the entire amount of the abrasive on the sieve was collected and dried, and the weight of the dried abrasive was measured. The weight of the abrasive at this time is the final weight.
The difference between the weight of the abrasive used in the first polishing test and the final weight was divided by the weight of the abrasive used in the first polishing test to determine the fineness of each abrasive. The results are shown in Table-6.

Test Examples 9 and 10 A barrel polishing test was performed using the abrasives VIII and X obtained in Example 5 and Comparative Example 5, and the surface gloss finishing performance of each abrasive was evaluated. The barrel polishing test was performed using the same small centrifugal barrel polishing machine as in Test Examples 7 and 8. The test method is as follows. That is, 250 to 1000 μ of abrasive VIII sized by sieving was placed in one side of a centrifugal barrel container of volume 1.
00g was charged, and abrasive material X was also 700
g prepared. After that, test pieces of SUS304 and aluminum were charged in the same manner as in Test Examples 7 and 8, and the same test was performed in the same procedure. The amount of grinding per unit time is shown in Table-7, and the surface condition and the pulverization rate of the test piece after the polishing test are shown in Table-8.

As described above, as shown in the test examples, the abrasive of the present invention is significantly superior to the conventional abrasives in polishing ability and surface gloss finishing performance, and it is possible to maintain this ability and performance for a long period of time. It is possible. Especially when used as a wet blasting abrasive, the generation of fine powder is also extremely small, which is another advantage of this abrasive. This means that the polishing power can be maintained for a long time and the mold during blasting and polishing can be maintained. It is also effective in preventing stains on molded products. Further, when the molded article is polished by using the present abrasive material, the surface of the mold material is almost free from roughness.

Also, when used as a dry barrel polishing material, rough polishing can be performed by a dry method, which not only eliminates the need for drying and drainage treatment when moving to surface gloss finish, but also consistently adopts a dry method. As a result, the polishing process can be fully automated.

As described in detail above, many of the advantages of the present abrasive are that the abrasive of the present invention is produced by suspension polymerization, and has an acute-angled protrusion as in a conventional abrasive. It is supposed that it is based on the shape that does not
In any case, as described above, the present abrasive material is superior as a blasting abrasive material for a molded product, a molded product such as metal or synthetic resin, or a dry barrel abrasive material for a machined product.

Claims (1)

[Claims] 1. A synthetic resin abrasive material comprising an unsaturated polyester resin obtained by suspension polymerization in an aqueous medium.