JPH036285A - Synthetic resin abrasive - Google Patents

Abstract

PURPOSE:To obtain an abrasive which has improved impact resistance and can effectively remove resin flash without impairing the appearance of a molded article, etc., by the suspension polymerization of an unsaturated polyester resin in an aqueous medium in the presence of a rubbery polymer. CONSTITUTION:An unsaturated dibasic acid and a glycol compound are esterified to give an unsaturated ester, which is then dissolved in a polymerizable vinyl monomer. A rubbery polymer is sufficiently dispersed in this solution, and the dispersion is made to undergo suspension polymerization in an aqueous medium in the presence of a polymerization initiator to five a slurry containing spherical polyester resin. This slurry is filtered to give a synthetic resin abrasive. The abrasive thus obtained can effectively remove resin flash from a molded article to give molded material almost free from surface roughening.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a synthetic resin abrasive material. More specifically, the present invention relates to a synthetic resin abrasive made of a rubber-modified unsaturated polyester resin obtained by suspension polymerization in an aqueous medium.

[Prior art and its problems] Semiconductor molded products such as ICs and LE1) (hereinafter simply referred to as molded products) generate mold resin flakes during molding, but this resin flakes are usually produced by dry molding. removed by blasting or polishing using a wet method.

Particles made of various materials such as alumina, glass beads, walnut shells, and synthetic resins are used in blasting abrasive materials. Among the abrasive particles made of the various materials mentioned above, those made of synthetic resin have the advantage that they can be selected with an appropriate hardness depending on the material of the molded resin, so they are suitable for blasting molded products. This synthetic resin abrasive material is often used for processing and polishing.

However, when this synthetic resin abrasive material is used for blasting and polishing of molded products, there are the following problems.

That is, since conventional synthetic resin abrasives are obtained by coarsely pulverizing synthetic resins that have been cured by casting or the like, they are polygonal in shape and have many acute-angled protrusions.

Therefore, when blasting and polishing is performed using an abrasive material with such a shape, when the molded product is blasted at high speed, the impact causes many sharp protrusions to break off and adhere to the molded product. There was a problem that the aesthetic appearance of the product was impaired. Furthermore, due to the loss of the acute-angled protrusions, the abrasive becomes smaller in size at an early stage, making it impossible to maintain the original polishing ability and forcing new abrasive to be replenished within a short period of time. Ta.

In order to solve the problems encountered with polygonal synthetic resin abrasives as described above, the present inventors first developed a truly spherical synthetic resin obtained by suspension polymerizing an unsaturated polyester resin in an aqueous medium. The abrasive material was crushed (Japanese Patent Application Laid-Open No. 63-351). However, according to subsequent research by the present inventors, the above-mentioned true spherical unsaturated polyester resin abrasive can be used in wet blasting polishing, which involves slurrying it with water and spraying this slurry at high speed onto a molded product. was able to recognize advantages due to its shape compared to conventional polygonal synthetic resin abrasives.

However, recent technological innovations in the semiconductor field are remarkable, and semiconductors are becoming more highly integrated as well as molding materials becoming more sophisticated and of higher quality. Along with this, the distance between the bins of lead frames tends to become narrower and narrower, and the strength of resin particles generated during molding increases dramatically.

Due to the reduction in the distance between the bins, using abrasive particles of the same diameter as in the past will cause clogging between the bins, making it necessary to use abrasive particles with a diameter smaller than the distance between the bins. As a matter of course, reducing the diameter leads to a decrease in polishing power, so the reality is that further improvement in polishing power is unavoidable.

One way to efficiently remove the resin debris that has become stronger through wet plastic polishing using an abrasive with a smaller particle size is to increase the injection pressure on the molded product. . However, the maximum injection pressure that can be employed in this method is limited to the upper limit of allowable scratches on the surface of the molded product. In addition, increasing the injection pressure is not necessarily a preferable method because it causes early destruction of the abrasive particles in most cases.

Another method is to increase the mass and surface hardness of the resin abrasive particles by incorporating an inorganic filler such as alumina or glass beads into the resin abrasive particles, thereby increasing the impact force generated by jetting. However, the internal structure of the resin abrasive particles containing the inorganic filler is clearly heterogeneous, and a significant decrease in impact resistance is inevitable.

On the other hand, in the case of dry blasting in which abrasive particles are sprayed directly onto the molded article at high speed, both the abrasive particles and the molded article are subjected to a much greater impact than in wet blasting. For this reason, although the breaking speed of the abrasive particles and the damage to the surface of the molded product have been significantly improved compared to conventional polygonal resin abrasives, a satisfactory situation has not yet been reached.

[Means to solve the problem]

The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, as a blasting abrasive material for molded products,
By using specific synthetic resin particles modified with specific additives, it is possible to effectively remove resin particles without damaging the aesthetic appearance of molded products, and moreover, compared to conventional synthetic resin abrasives, The present inventors have discovered that far superior impact resistance can be imparted by using the same method, and have completed the present invention.

That is, the present invention provides a novel synthetic resin abrasive material characterized by being made of a rubber-modified unsaturated polyester resin obtained by suspension polymerization in an aqueous medium.

[Specific conditions for carrying out the invention] The present invention will be explained in detail below.

As explained above, the object to be polished by the abrasive of the present invention is mainly a molded product. Most of the synthetic resins used for this molding are thermosetting resins such as epoxy and phenol, and silicic anhydride is usually added to these resins to improve strength and reduce the coefficient of linear expansion. It is used in combination with inorganic fillers such as. Therefore, in order to remove particles from molded products based on resins such as epoxy and phenol by blasting and polishing,
The hardness must correspond to the hardness of the base resin, and it must also have good polishing performance. Furthermore, it is preferable that the abrasive particles are not easily destroyed.

As mentioned above, an object of the present invention is to provide a novel abrasive material that can effectively remove resin debris from molded products.

Usually, the resin particles generated in a molded product have the same composition as the mold resin, and the selection of the mold resin is determined by taking into consideration the application, performance, cost, etc. of the molded product.

In other words, the mechanical strength of resin burrs generated on molded products varies widely depending on their history of occurrence, composition, shape, location of occurrence, etc., and the abrasive particles that can be used to efficiently remove these burrs also vary. A delicate balance of hardness and toughness is required accordingly.

For example, multi-pin type ICs and LSIs with narrow distance between bins.
Regarding strong dam burrs and Franche burrs that occur on the frame, emphasis should be placed on improving the hardness of the abrasive particles rather than the toughness of the abrasive particles. In order to prevent damage to the sealing resin surface, emphasis is often placed on improving toughness, as it is necessary to minimize damage to the surface of the sealing resin.

As mentioned above, the strength of the abrasive to be used should be determined after sufficiently observing the state of the resin particles to be removed. The types and amount of rubbery polymer added, particle size of rubber particles, structural mode of the rubber phase and continuous phase, graft ratio, dissolution of the rubber phase into the continuous phase, etc. are usually considered when improving the Among the matters, there is no need to strictly specify anything other than the type and amount of rubbery polymer used in blasting and polishing.
The balance between hardness and toughness required for unsaturated polyester resin abrasive particles can usually be adjusted to a very satisfactory degree by appropriately combining the type and amount of the rubbery polymer added.

According to the research conducted by the present inventors, such abrasive materials are most preferably true spherical particles obtained by suspension polymerizing an unsaturated polyester resin in an aqueous medium in the presence of a rubbery polymer.

The abrasive material of the present invention can be obtained by conventional methods.

That is, first, an unsaturated dibasic acid and a glycol compound are subjected to an esterification reaction to form an unsaturated ester.

This is added to the polymerizable vinyl monomer, mixed and dissolved, and then the rubbery polymer is added to this solution and thoroughly dispersed. If this is suspended polymerized in an aqueous medium in the presence of a polymerization initiator, a slurry containing spherical unsaturated polyester resin can be obtained. material can be obtained.

Incidentally, since this abrasive material still has moisture attached to it after being filtered, it is naturally necessary to dry it when used as a dry abrasive material. Further, this abrasive material may be used after adjusting the particle size by a method such as sieving. In the present invention, as described above, it is first necessary to generate an unsaturated ester from an unsaturated dibasic acid and a glycol compound.

As the unsaturated dibasic acid, α,β-unsaturated dibasic acids such as maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, and chlorinated maleic acid are suitable, and one or more of these are used. .

Furthermore, the unsaturated dibasic acids include phthalic anhydride, isophthalic acid, terephthalic acid, monochlorophthalic acid, dichlorophthalic acid, trichlorophthalic acid, het's acid, tetrachlorophthalic anhydride, tetrabromo phthalic anhydride, endomethylenetetrahydrophthalic anhydride, Adipic acid, succinic acid,
There is no problem in adding an appropriate amount of a saturated dibasic acid such as cepatic acid, glutaric acid, pyridic acid, etc.

On the other hand, as glycol compounds, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 1.3
Propylene glycol, 2.3 butylene glycol, 1
．． Preferred are 4-butylene glycol, neopentyl glycol, hexylene glycol, octylene glycol, bisphenol A dioxypropyl ether adduct, hydrogenated bisphenol A1, or alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc. trimethylolfuropane,
There is no problem even if polyhydric alcohol such as glycerin is used together.

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

Next, a polymerizable vinyl monomer is added to this unsaturated ester and mixed thoroughly, and then a rubbery polymer is added to this mixed solution and stirred under high shear force to atomize the rubbery polymer and Disperse evenly in the mixture.

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

In the present invention, the mixing ratio of the unsaturated ester and the polymerizable vinyl monomer cannot be particularly limited because it varies greatly depending on the respective types of the unsaturated ester and the polymerizable vinyl monomer and the required performance of the abrasive material, but it is usually unsaturated. The amount of the polymerizable vinyl monomer is 10 to 150 parts by weight, preferably 20 to 100 parts by weight, per 100 parts of polyester.

Examples of the rubbery polymer that can be used in the present invention include butadiene rubber, styrene-budadiene copolymer rubber, styrene-budadiene-styrene copolymer rubber, butadiene-acrylonitrile copolymer rubber, isoprene rubber,
Chloroprene rubber.

In some cases, a small amount of a monomer copolymerizable with the above rubber, such as acrylic acid, methacrylic acid, acrylamide, acrylic ester, and methacrylic ester, may be added.

In addition to the above rubbery polymer, 2.4 or 2-6
-) The isocyanate base '4, typified by lylene diisocyanate and 4,4°-diphenylmethane diisocyanate, is a substance, or the isocyanate base is a reaction product of a substance and a diol or/and polyol, and the unreacted isocyanate group is Even if the remaining polymer is used, results comparable to those obtained using the above-mentioned rubbery polymer can be obtained.

The amount of the rubbery polymer added in the present invention depends on the type of rubber used, but is usually 3 to 20 parts by volume, based on a total of 100 parts by volume of the unsaturated ester and polymerizable vinyl monomer.
Preferably it is 5 to 15 parts by volume.

If the amount added is less than 3 parts by volume, the effect of addition will be weak;
If the amount exceeds the volume part, the inherent rigidity of the unsaturated polyester resin decreases, which is not preferable.

Atomization and dispersion of the added rubbery polymer is usually carried out using a disper, triple roll, or the like.

The optimum particle size of atomized rubbery polymer is usually 2 to 5 μm.
However, in the present invention, as mentioned above, it is not necessary to strictly control the rubber particle size.0 As long as the dispersed rubber particles are stabilized without secondary agglomeration, the particle size falls within the optimum range. Even outside, the impact resistance can be improved while taking advantage of the rigidity of the unsaturated polyester resin.

In the present invention, the rubbery polymer may be added after mixing the unsaturated ester and the polymerizable vinyl monomer, but if the unsaturated ester has a high viscosity, it may be added to the polymerizable and vinyl monomers in advance. After sufficiently atomizing and dispersing under high shear force, the unsaturated ester is mixed with the unsaturated ester, or a portion of the polymerizable vinyl monomer to be used is taken out and dispersed therein, and then the unsaturated ester is mixed with the unsaturated ester. It is preferable to add it to the mixture of the saturated ester and the remaining polymerizable vinyl monomer.

In the present invention, a small amount of a suitable stabilizing agent may be added in order to stabilize the dispersed particles of the rubbery polymer.

In the present invention, after adding a polymerization initiator and mixing thoroughly,
This is dropped into an aqueous medium that is sufficiently stirred to undergo suspension polymerization.

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, azobisisobutylnitrile, azobis(2,4-dimethylvalerol), etc. Commonly known compounds are used, such as azo compounds such as nitrile), water-soluble peroxides such as hydrogen peroxide, and potassium persulfate. The amount added varies slightly depending on the raw materials such as the unsaturated dibasic acid, glycol compound, polymerizable vinyl monomer and rubbery polymer, polymerization conditions, etc., but the total amount of each raw material mentioned above is N1.
0.1 to 10 parts by weight is suitable.

In addition, if necessary, a curing accelerator such as cobalt naphthenate, N,N'-dimethylaniline, or cobalt octenoate may be added at a rate of 0.1 to the total i too weight parts of each of the above raw materials.
There is no problem in adding up to 2.0 parts by weight.

In the present invention, water itself may be used as the aqueous medium, but
Deformation of particles during polymerization of suspension polymers, excessive growth,
Alternatively, it is preferable to add an appropriate amount of a suspension stabilizer to prevent secondary agglomeration of particles.

The suspension stabilizer is not particularly limited (but known ones can be used; for example, polyvinyl alcohol, methylcellulose, hydroxycellulose, water-soluble polymeric substances such as polyacrylic acid, magnesium oxide, calcium phosphate, etc.). Water-insoluble inorganic salts, sodium alkylbenzenesulfonate, surfactants such as polyoxyethylene nonylphenol ether, etc. are used alone or in combination.The amount added varies depending on the type of raw materials, polymerization conditions, etc. The amount is preferably in the range of 0.1 to 30 parts by weight based on 100 parts by weight of the total amount of the above raw materials.

The polymerization temperature, polymerization time, aqueous medium stirring conditions, etc. during suspension polymerization in the present invention are appropriately selected depending on the type and amount of raw materials, the particle size of the desired polymer, etc., but it is usually carried out by a known method. 9 For example, the polymerization temperature varies depending on the type of polymerization initiator and the amount added, but is usually 20 to 100°C,
The temperature is preferably 60 to 90°C, and the polymerization time is generally about 2 to 20 hours, preferably 4 to 15 hours.

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

The shape of the unsaturated polyester resin of the present invention obtained by B turbidity polymerization is minute spherical, but its particle size and particle size distribution depend on the type and amount of suspension stabilizer added, stirring speed, unsaturated polyester and polymerization. It can be adjusted to some extent by changing the method of adding the mixture of the rubbery vinyl monomer and the rubbery polymer.

Furthermore, in the present invention, in order to strengthen the abrasive power of the abrasive,
An appropriate amount of an inorganic filler can also be added to a liquid mixture of an unsaturated ester, a polymerizable vinyl monomer, and a rubbery polymer for polymerization.

Any inorganic filler can be used as long as it can enhance the abrasive power of the abrasive, but usually,
Silicic anhydride, titanium oxide, zirconium oxide, calcium carbonate, clay, asbestos, talc, glass peas, etc. are preferably used.

The amount of inorganic filler added is 5 to 100 parts by weight per 100 parts by weight of the total amount of unsaturated polyester and polymerizable vinyl monomer.
Appropriate parts by weight. If the amount added is less than 5 parts by weight, the effect of strengthening the polishing force will be weak, and if it exceeds 100 parts by weight, the abrasive will be easily destroyed during polishing, and the abrasive will not only have a tendency to become pulverized, but also This is not preferable because it may damage the object to be polished.

In addition, when adding inorganic fillers, dispersants,
Regardless of the addition of antisettling agents, various coupling agents, etc., or the addition of inorganic fillers, antistatic agents,
It is also possible to add a surfactant or the like to the mixture of the unsaturated polyester, the polymerizable vinyl monomer, and the rubbery polymer.

C Examples and Comparative Examples] The present invention will be specifically described below with reference to Examples and Comparative Examples. In addition, all parts below indicate parts by weight unless otherwise specified.

Example 1 88 parts of a commercially available liquid unsaturated polyester resin (manufactured by Mitsui Toatsu Chemical Hat, trade name: Nister 1l-2354) prepared by dissolving an unsaturated ester in a styrene monomer were added in advance to 7 parts of a styrene monomer and liquid butadiene-acrylonitrile rubber ( Manufactured by Ube Industries ■Product name: HYCARVTBNX 130
A solution in which 5 parts of 0X23) was dissolved was added to adjust the content of the rubbery polymer to approximately 5.5% by volume, and then stirred under high shear force using a disper to fully dissolve the rubbery polymer. It was atomized and dispersed.

Next, 1.5 parts of azobisisobutyronitrile was added as a polymerization initiator to this mixed solution, and the mixture was thoroughly mixed again.

Polyvinyl alcohol (manufactured by Denki Kagaku Kogyo ■) was added as a suspension stabilizer to 300 parts of ion-exchanged water in a polymerization tank equipped with a stirrer, a gas blowing pipe, and a reflux condenser with an internal volume of 50 mm.
An aqueous solution in which 2 parts of Denkapoval B-20F (trade name) (trade name) was dissolved was prepared, and a mixture of the above polymerization initiators was added dropwise to this aqueous medium over 2 minutes while stirring to disperse it as droplets. for 2 hours at 75°C and then at 85°C for 2 hours.
Suspension polymerization was carried out at °C for 3 hours. During the polymerization, 142 parts win of nitrogen gas was flowed into the polymerization tank, and the polymerization was carried out in a nitrogen gas atmosphere.

After the polymerization is completed, the resulting slurry containing rubber-modified unsaturated polyester resin particles is separated using a small centrifuge, thoroughly washed with water, and dried at 80"C for 5 hours to form a pale yellow, opaque slurry with an average particle size of 150 μm. An abrasive material (■) consisting of truly spherical particles was obtained.

Example 2 The amount of liquid butadiene/acrylonitrile rubber used was 10
The polymerization was carried out in the same manner as in Example 1, except that the amounts of liquid unsaturated polyester resin and styrene monomer were changed to 83.4 parts and 6.6 parts, respectively. An abrasive material (■) consisting of opaque spherical particles was obtained.

Example 3 All procedures were carried out except that 5 parts of hexamethylene diisocyanate water adduct (manufactured by Mitsui Toatsu Chemicals, trade name NP-1100) was used as the isocyanate group-containing substance in place of the liquid butadiene-acrylonitrile rubber in Example 1. Polymerization was performed in the same manner as the side mold, and the average particle size was 140 p.
An abrasive material (2) consisting of pale yellow, opaque, true spherical particles of m was obtained.

Example 4 Same commercially available liquid unsaturated polyester resin 68 as Example 1
7 parts of styrene monomer and 7 parts of liquid butadiene.
A solution containing 5 parts of acrylonitrile rubber (same as in Example 1) was added and stirred under high shear force to sufficiently atomize and disperse the rubbery polymer. Next, glass beads having a particle size of 40 μm or less (trade name: Toshiba Glass Peas G, manufactured by Toshiba Varotini) were added to this mixed solution in advance.
l? 31M) was surface-treated with an aqueous solution of a silane coupling agent (manufactured by Toshiba Silicone ■, trade name TSC8311), 20 parts of an inorganic filler obtained by drying was added, and the glass beads were mixed again under high shear force. 1.2 parts of azobisisobutyronitrile was added as a polymerization initiator to the mixed solution, and the mixture was thoroughly mixed again. Hereinafter, polymerization was carried out in the same manner as in Example 1 using the same aqueous medium, and the average particle size was 200.
An abrasive material (■) consisting of white, opaque, true spherical particles with μ shoulders was obtained.

Comparative Example 1 All operations were the same as in Example 1 except that liquid butadiene/acrylonitrile rubber was not used and the amounts of liquid unsaturated polyester resin and styrene monomer were changed to 92.6 parts and 7.4 parts, respectively. Polymerization was carried out to obtain an abrasive material (2) consisting of pale yellow, transparent, true spherical particles with an average particle diameter of 130 μm.

Comparative Example 2 All operations were the same as in Example 3 except that liquid butadiene/acrylonitrile rubber was not used and the amounts of liquid unsaturated polyester resin and styrene monomer were changed to 71.6 parts and 7.4 parts, respectively. Polymerization was carried out to obtain an abrasive material (2) consisting of white, opaque, truly spherical particles with an average particle size of 190 μm.

Test Examples 1 to 6 Wet blast polishing tests were conducted using each of the abrasives obtained in Examples 1 to 3 and Comparative Examples 1 to 3, and the performance of each abrasive was evaluated. In order to facilitate comparison of evaluations, each abrasive was sieved to have a uniform particle size of 105 to 250 μm, and then used for the test.

The wet blasting test was conducted using a liquid honing machine (Model Ll-5) manufactured by Fuji Seiki Seisakusho.

The test method is as follows. That is, each abrasive material was made into a slurry with water, and each of the four slurries was adjusted to 30% by weight.

This slurry was applied at a projection pressure of 4 kg/c+m"-G and a projection distance of 50+u+. First, the weight loss of the acrylic resin plate was used as the initial polishing amount. Then, using a tin plate, the same pressure and distance as above were applied. After blasting for 1 hour, the acrylic resin plate was blasted again for 1 minute.The acrylic resin plate and the tin plate were repeatedly blasted alternately, and the change over time in the amount of polishing of the acrylic resin plate was measured.The results are shown in the table below.
Shown in 1.

Furthermore, a portion of the abrasive slurry was sampled every 5 to 10 hours during the above blast polishing, and a JIS slurry with an opening of 105μ was used.
i! ! Wet classification was performed using a sieve, and the proportion of fine particles under the sieve was measured, and this was taken as the fine powder generation rate. The results are shown in Table-2.

Separately, wet blast polishing of unpolished IC-sealed molded products was performed using new abrasives 1 to 3, and the performance of removing resin debris and dirt and roughness on the surface of the molding material were observed. The polishing method was as follows. That is, the slurry concentration of each abrasive material is 30111%, and the projection pressure is 4 kg/a.
m"-G, projection distance 5C1, and polishing time was 2 seconds per chip of the IC encapsulation molded product. The polishing results were evaluated on a scale of 10, with 10 being the best and 10 being the best, and 1 being the most acceptable for practical use. The worst one was given a score of 5, and the worst one was given a score of 1. The results are shown in Table 3.

As shown in the test examples above, the abrasive of the present invention has significantly superior impact resistance when sprayed onto molded products, etc., compared to conventional abrasives, and maintains its initial abrasive power over a long period of time. It is possible to do so.

Another advantage of this abrasive material is that the generation rate of fine powder is extremely low.This makes it possible to sustain polishing for a long time, and it is also effective in preventing stains on molded products during blasting and polishing. . Furthermore, by polishing a molded product using this abrasive, it is possible to obtain a molded product with almost no surface roughness.

The many advantages of the abrasive material of the present invention, as described above, are that, as already explained in detail, it is composed of truly spherical unsaturated polyester particles obtained by suspension polymerization in the presence of a rubbery polymer. It is presumed that this is based on its good balance of hardness and toughness compared to conventional synthetic resin abrasives, but in any case, as explained above, the abrasives of the present invention are suitable for blasting and polishing of molded products. It is an extremely excellent material.

Table 1 Table 2 Table 3 Table 3 [Effects of the Invention] As explained in detail above, the present invention is based on a novel method obtained by suspension polymerizing an unsaturated polyester resin in an aqueous medium in the presence of a rubbery polymer. Since it is a synthetic resin abrasive, its impact resistance is much improved compared to conventional synthetic resin abrasives. Further, in the abrasive material of the present invention, the delicate balance between hardness and toughness of the abrasive particles can be adjusted over a wide range by appropriately changing the type and amount of the rubbery polymer added to the resin.

For this reason, in response to the reduction in the diameter of abrasive particles and the accompanying decrease in polishing power, which is forced by the higher integration of semiconductors and the higher quality of molding materials, the jetting pressure of the water slurry of the abrasive is as high as possible. This can be addressed by increasing the Additionally, even when adding inorganic fillers to the abrasive particles to increase the polishing power, they do not break down as quickly as conventional synthetic resin abrasives, greatly reducing the amount of replenishment required during polishing. Is possible. Furthermore, for molded products such as LEDs that are extremely sensitive to damage to the sealing resin surface,
Due to the effect of imparting rubber elasticity, pars can be efficiently removed without damaging the surface of the sealing resin.

Furthermore, even in dry blasting, which is subjected to a much stronger impact than wet blasting, it is possible to remove particles without damaging the mold resin surface. Problems such as early fracture and adhesion of fracture particles to molded products can be significantly improved.

As described above, the present invention has many advantages as a blasted abrasive material, and its economic effects are significant.

Furthermore, the abrasive material of the present invention is not limited to polishing molded products by blasting, but also exhibits excellent polishing ability when used for metal surface polishing, cleaning, etc.

Furthermore, the abrasive material of the present invention is not limited to the blasting method, but is also an excellent abrasive material for a wide range of polishing methods such as the barrel method.

Claims (1)

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