JPS59124573A - Abrasive material and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain an abrasive material which can be used for a long period by using, as abrasive material, a synthetic resin particle which has cracks which can be cleaved by an external force, so that new edges are always formed, because the particle is cleaved by the shock during vapor blasting. CONSTITUTION:An unsaturated polyester resin block is formed by pouring the unsaturated polyester material added with catalyst into a mold. Then, said block is cut to form pellet form, and after pulverized by a crasher, etc., further said pellet is pulveriszed mintely by a ball mill, etc., and an unsaturated polyester resin particle 6 having a number of cutting edges is obtained. Then, said pulverized body 6 is further pulverized minutely by using a compression machine in which the crashed pieces 3... are having a relatively high hardness held onto the opposite surface of the upper and the lower molds 1 and 2 through adhesive layers 4a and 4b, and an abrasive material 8 which has cracks 7 which can be cleaved by an external force is obtained. Said abrasive material 8 is used for removing the burr on a molded article, in a blasting apparatus.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an abrasive material made of synthetic resin, and in particular to an abrasive material that has the effect of generating sharp edges during jetting processing (hereinafter referred to as self-regeneration effect) and a method for producing the same. Pertains to.

[Technical background of the invention]

In order to perform surface treatment on soft metals and remove deburrs from electronic equipment parts, a method is adopted in which the abrasive material is accelerated with compressed air and jetted by colliding with the soft metal or electronic equipment parts being processed. ing.

Conventionally, walnut flour and apricot flour have been used as such abrasives.

[Problems with background technology]

However, since walnut flour and apricot flour, which are vegetable-based flours, have high elasticity and stickiness when dry, when these are used as abrasives to blast the workpiece or workpiece, only the edges of the abrasives are removed. The disadvantage was that the polishing force became rounded and the polishing power decreased in a short period of time. In particular, when such an abrasive is applied to remove resin particles from semiconductor molded products,
The resin particles existing on the lead frame and between the leads of the molded product cannot be sufficiently removed. [Object of the Invention] The present invention provides a polishing method that can exert good polishing power over a long period of time when spraying a workpiece. [Summary of the Invention] The abrasive material of the present invention is made of synthetic resin granules having a rack that can be opened by external force. The granules have irregularly formed ridges, and the impact during the blasting process causes them to crack and fall off along the ridges, forming new sharp edges.For this reason, the granules have high hardness. It is preferable to use a synthetic resin with low ductility. Examples of such synthetic resins include thermosetting resins such as epoxy resins, urea resins, and polyester resins, as well as relatively hard thermosetting resins such as acrylic resins.The synthetic resin particles may be sprayed with compressed air. For the purpose of grinding the workpiece and removing resin particles during machining, it is desirable to have a structure with a large number of cutting edges. Further, the shape of the synthetic resin granules may be arbitrary, such as flat, acicular, etc., and all of these synthetic resin granules with different shapes may be mixed to form the abrasive material. The size can be freely selected depending on the purpose of the abrasive, but for example, when used for removing resin debris from molded products, the average diameter (% of the sum of the maximum diameter and minimum diameter of one particle) is 0.05. ~20. A distribution with a peak within the range of - is desirable.

The method for manufacturing the abrasive material of the present invention described above consists of a method of molding a synthetic resin material and a method of granulating the synthetic resin material, and when molding and/or granulating the synthetic resin material, cracks are removed. It is characterized by generating.

Cracks can be generated by molding a synthetic resin material by making full use of the exothermic reaction during molding of the thermosetting resin to maintain internal strain through thick molding, or by forming the thermosetting resin into granules in advance. (Particle size: 0.05 to 5 turt) The particles are dispersed as cores in a synthetic resin and molded, and the shrinkage that occurs during molding causes cracks to occur around the core bodies.
Furthermore, there is a method of pulverizing the synthetic resin material by heating or adding a catalyst to gel it, applying strain at a stage where hardening has not progressed, and then coarsely pulverizing it. Due to its brittle characteristics, countless cracks may occur.The synthetic resin material is heated at high temperatures (50~
A method in which the molding reaction occurs rapidly by molding at 150°C) and internal strain is rapidly generated. After molding, the synthetic resin material is immersed in a chemical solution such as acetone or methanol, or in boiling water. It is soaked and softened to generate fine particles in the molded product, and further crushed when crushed.
A method for generating cracks, a method in which a processing tool with a large number of cutting edges is used to apply pressure to make coarse particles into fine particles and forcibly generate cracks, and a synthetic resin material is made into coarse particles after molding. A method in which the synthetic resin material is cooled to a temperature of 10°C or less, preferably -20°C or less, and then turned into fine granules at the stage of brittleness.
Appropriate methods include heating the material to a temperature of 50°C or higher to reduce its strength, turning it into fine particles and generating cracks, and combining at least two of the above methods to generate cracks in the powdered abrasive material. However, since the abrasive material of the present invention is composed of synthetic resin granules having a rack that can be opened by external force, this is accelerated with compressed air,
When the workpiece is jetted by colliding with the workpiece, the impact force of the abrasive material can grind or remove debris from the workpiece, and the impact force during the jetting process can easily be applied along the cracks. The new sharp edges are formed by cracking and falling off, and the grinding or deburring performance of the workpiece can be maintained even during long-term use.

In addition, if an abrasive material is formed by retaining a surfactant in the synthetic resin granules, when a workpiece is subjected to dry blasting using this abrasive material, it is possible to completely prevent the generation of electrical charges on the workpiece. This has the effect of simplifying the cleaning process of the workpiece after blasting.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on examples.

Example 1 First, unsaturated polyester material Nister R235A-1
(Product name: Mitsui Toatsu Chemical Co., Ltd.) with catalyst 55% ME
KPO (methyl ether-ketone bar oxide)
Add 2% of
Pour into the mold in between. The unsaturated polyester resin block obtained in this way is cut into pellets, which are coarsely ground using a crusher, a crusher, etc., and then coarsely pulverized using a ball mill, roll mill, impact grinder, etc. Then, as shown in Fig. 1, the facing surfaces of the upper and lower molds 1.2 were prepared by finely pulverizing the unsaturated polyester resin particles having a large number of cutting edges with an average diameter of about m" 0.7 hi. A compressor with a structure in which crushed pieces 3 of a material much harder than synthetic resin (for example, diamond) are held through adhesive layers 4a and 4bk is prepared, and between the upper and lower molds 1 and 2, a compressor made by the above method is prepared. A large number of edges 5... fully loaded polyester resin granules 6... are fully loaded and compressed into the upper and lower molds 1.2, thereby making the granules 6 in contact with the front H self-crushed pieces 3... Furthermore, fine grains were further developed, and an abrasive material having an average grain size of about 0.3 and having a rack 7 which could be opened by an external force was obtained.Next, the semiconductor shown in FIG. The removal of resin debris from a molded product will be explained using the wet blasting device shown in Figure 3.After the entire lead flail on which the semiconductor element is mounted is placed in the mold, epoxy is poured into the mold. The entire resin was injected to form a semiconductor molded product 1-1 in which a semiconductor element (not shown) on a lead frame 9 was fixed in a resin layer 10''c as shown in FIG. During molding, resin particles I2 were generated on the lead frame 9 near the resin layer 10 and between the leads of the lead frame 9.

Next, the hopper I installed in the pressurizing chamber 13 shown in FIG.
The polishing blades 8 and water 15 were housed in the container 4 at a ratio of 1:3. Next, the first pump 16 is operated to suck in the polishing blades 8 along with the water 15, and these are transferred to the hopper 14.
The abrasive material 8 is agitated by being forcibly fed to the bottom.
A slurry was prepared by uniformly dispersing O. Next, the second pump 17f was operated to suck up the slurry and introduce it into the gun I8, where it was dispersed and accelerated by compressed air from the air introduction pipe I9. A three-phase high-speed jet stream 20 of water, abrasive material, and air is injected toward the semiconductor molded product (not shown) that is transported into the processing chamber 13. When sprayed on the product,
As shown in FIG. 4, the abrasive material 8 having a large number of edges 5 collides with the resin particles 12 attached on the lead frame 9 of the molded product 11 and between the leads of the lead frame 9. As shown in FIG. The resin burr I2 is made of a thermosetting epoxy resin, and the resin burr 1 is made of a thermosetting epoxy resin due to the concentrated (local) impact force caused by the edge 5 of the relatively brittle abrasive material 8 and the vibration accompanying the impact force.
2, a crack 21 occurs. Furthermore, water may enter the cracks 21 that have occurred in the resin pad 12, causing the lead frame 9
and enters the interface between the resin burr 12 and acts to float the resin burr 12' relative to the lead frame 9. Furthermore, since the abrasive material 8 having a large number of edges 5 collides with the cracks 21 of the resin burr 12, the resin burr is damaged by the infiltrated water. Coupled with the lifting action of the resin burr 12
Furthermore, since the abrasive material 8 has irregular racks 2 from the surface toward the inside, the abrasive material 8 is prone to colliding with the semiconductor molded product 1-1.
It splits along the crack 7, and the rounded edges fall off to form new sharp edges. As a result, even after long-term use, the resin Paris I of semiconductor molded product II
2 removal performance can be maintained.

Therefore, by spraying, for example, the semiconductor molded product 1-1 using the abrasive material 8 of the present invention, the resin bar and the glass 12 of the molded product 1-1 can be effectively removed, and the abrasive material Cracks in 8, cracks along 7...
The new sharp edges created by the falling off caused molded product 1-
1 minute location (for example, between the leads of lead frame 9, etc.)
The resin particles 12 attached to the surface can be completely removed without leaving any residue.

In fact, the test shown below confirmed that the abrasive material of Example 1 had excellent deburring performance.In addition, in this test, a comparative example will also be described.

Comparative Example: Unsaturated polyester material Nister R235A-1 (Product name: Mitsui Toatsu Chemical Co., Ltd. Catalyst 55CH MEKPO (
Add 2% of methyl ethyl ketone oxide),
Cast into a mold of length x width x height 300 mm x 30 QrIgL x 20 mm.The synthetic resin block thus obtained was coarsely crushed using a crusher and a non-marine, and then milled.

Using a roll mill or impact mill, the average particle size is reduced to 0.
Synthetic resin granules of around 3B were obtained.0 However, using the abrasive material with cracks of Example 1 and the abrasive material with a small number of cracks of the Comparative Example, it was possible to remove the resin/(stain) of semiconductor devices. When the deburring performance was investigated, the graph shown in Figure 5 was obtained.The test conditions were as follows: After deburring the semiconductor devices in a continuous 24-hour wet blasting machine, an additional 10,000 pieces were processed. (v
Out of the 1000 workpieces randomly sampled from these 10000 workpieces, the percentage of workpieces that have been completely removed without v-removal is defined as the deburring property, expressed as a 100% percentage. As is clear from FIG. 5, the abrasive material of Example 1 has a deburrability of almost 100%, whereas the abrasive material of the comparative example has a deburrability as low as approximately 80q6. , it can be seen that the abrasive material of the present invention has excellent deburring properties.

Note that the injection processing using the abrasive material of this example is not limited to the purpose of removing resin debris from semiconductor molded products as described above, but also for removing resin debris from general molded products and the surface of soft negative metals. It can be similarly applied to processing, etc.

Example 2 The 5 s % MzKp was added to the Nistar R235A-1.
.

was added twice, and poured into a mold with length x width x height of 300 mm x 300 mm x 200 LL and hardened to obtain a block. At this time, the temperature at the center of the block reaches 250°C or higher, causing internal strain and innumerable cracks.The entire block with two blocks formed in this way is coarsely crushed using a crusher, a hammer, and then a ball mill. , a roll mill, or an impact crusher was used to obtain an abrasive material containing a large number of glue particles with an average particle size of around 0.3M. Similar to Example 1, the abrasive material in this Example also has significantly improved deburrability.

Example 3 20 parts of the pulverized material with a particle size of 111 g or less obtained in Example 2 was mixed with 1100 parts of Nister R235A-1 as a core, and then 2 parts of the 551MEKPO was added, and the length x width x height was 30.
The mixture was poured into a QIIulX 300wnX 2 Qm mold, molded and cured to obtain a block. Then, after applying a thermal shock such as rapid heating to induce internal strain in the block and generate countless cranks, the block was prepared using the same method as in Example 2, with an average grain size of around 0.3 An abrasive material containing many cracks was obtained. Similar to Example 1, the abrasive material in this Example also has significantly improved deburrability.

Example 4 0.3% of the 55% MEKPO was added to the Nistar R235A-1 and cast into a mold with the same dimensions as in Example 1.
After the block is reacted and gelled at a temperature near ℃, impact strain is immediately applied to generate cracks in the block. Then, the sufficiently hardened block was polished in the same manner as in Example 2, with a large number of cracks having an average grain size of around 0.3M.

Similar to Example 1, the abrasive material in this Example also has significantly improved deburrability.

Example 5 When performing the same molding as in Example 4, the temperature of the synthetic resin was lowered to 1
Cured at 00 to 150℃ to create internal strain in the block.
'(i= After inducing all the cranks, the entire abrasive material with many cracks with an average particle size of around 0.39 was prepared using the same method as in Example 2. The abrasive material in this example also had As in Example 1, the deburrability is significantly improved.

Example 6 A block was cast into a mold of the same size using the same resin and the same catalyst conditions as in Example 1, and then molded and cured.The block was heated to 150-200°C and then rapidly cooled to below -10°C, or the block was molded and cured at -10°C. 100~ below from Q temperature.

After generating two cracks in the block by rapidly heating it to a temperature of 200°C, the same method as in Example 2 was used to obtain an abrasive material containing many cracks with an average particle size of around 0 parts. Ta. The abrasive material in this example also has significantly improved deburrability as in the example.

Example 7 A block cast and cured using the same resin and the same catalyst conditions as in Example 1 into a mold of the same size was coarsely ground in the same manner as in Example 2, and a total acetone solution of the coarsely ground synthetic resin particles was obtained. After being immersed in a chemical solution such as a methanol solution for one week, the chemical solution was removed and the material was finely pulverized to obtain an abrasive material with a large number of cracks and an average particle size of about 0.3 parts. Similar to Example 1, the abrasive material in this Example also has significantly improved deburrability.

Example 8 A block cast and cured using the same resin and the same catalyst conditions as in Example 1 into a mold of the same size was coarsely pulverized in the same manner as in Example 2, and a total of 20 coarsely pulverized synthetic resin particles were obtained. ℃ and finely pulverized in the same manner as in Example 2 to obtain an average particle size of 0.
An abrasive material with many cracks of about 3 parts was obtained. Similarly to Example 1, the abrasive material in this example also has significantly improved deburrability.

Example 9 Coarsely pulverized synthetic resin particles were coarsely pulverized in the same manner as in Example 2, heated to 170°C, and finely pulverized in the same manner as in Example 2 at an oven temperature. An abrasive material with many cracks of around 0.3 was obtained. Similar to Example 1, the abrasive material in this Example also has significantly improved deburrability.

The abrasive material of the present invention is not limited to those obtained by the specific manufacturing methods from Example 1 to Example 8, but can be obtained by combining at least two or more of the eight manufacturing methods described above. A polished abrasive may also be used.

〔Effect of the invention〕

As described in detail above, according to the present invention, when injection processing is performed on workpieces such as semiconductor molded products or other molded products or soft metals in which resin flakes are generated during molding, the workpieces can be sprayed even after long-term use. The present invention provides an abrasive material having good abrasive force capable of removing resin particles or maintaining grinding performance, and a method for manufacturing the same.

[Brief explanation of the drawing]

Figure 1:], , is a schematic sectional view of a compressor used for manufacturing an abrasive material according to an embodiment of the present invention, Figure 2 is a plan view of a semiconductor molded product, and Figure 3 is the same as Figure 1. (-l's research ■
FIG. 4 is a cross-sectional view illustrating the removal of resin debris using an abrasive material, and FIG. 5 is an illustration of an embodiment of the present invention. It is a graph showing deburrability of an example and a comparative example. 1.2... Mold, 3... Crushed pieces made of carbide material, 5
...Edge, 7...Crack, 8...Abrasive, 9
...Lead frame, 1-1 semiconductor molded product,
12.° Resin Paris, 13... Processing room, 14... Hopper, 15... Water, 16. 11'... Pump, 18.
...Gun, 2)...Crack 0 Fang 1 Fig. Fang 2 Fig. Fang 3 Fig. 4 Fig. 5

Claims (10)

[Claims] (1) An abrasive material comprising synthetic resin granules having a rack that can be opened by external force. (2) An abrasive material comprising a method of forming a synthetic resin material into a shape and a method of granulating the synthetic resin material, and generating cracks when the synthetic resin material is completely formed and/or granulated. manufacturing method. (3) The method for manufacturing an abrasive material according to claim 2, characterized in that a synthetic resin material that retains all internal strain is molded. (4) A method for manufacturing an abrasive material according to claim 2, characterized in that a synthetic resin material is molded using thermosetting resin particles as cores. (5) A method for manufacturing an abrasive material according to claim 2, characterized in that the synthetic resin material is gelled by heating or the addition of a catalyst, and then strain is applied at a stage where hardening has not progressed. (6) A method for manufacturing an abrasive material according to claim 2, characterized in that a synthetic resin material is molded at a high temperature. (7) The method for producing an abrasive material according to claim 2, which comprises applying a thermal shock to the synthetic resin material to generate cracks. (8) The method for manufacturing an abrasive material according to claim 2, wherein the synthetic resin material is immersed in a chemical solution after being molded. (9) The synthetic resin material is granulated by first making it into coarse particles and then making it into fine particles. 3. The method for producing an abrasive material according to claim 2, wherein the abrasive material is formed into a solid material. (10) The granulation of the synthetic resin material is carried out by first making it into coarse particles and then making it into fine particles, and then turning the coarse particles into fine particles at a temperature of 10°C or less. A method for producing an abrasive material according to claim 2, characterized in that: Ql) The granulation of the synthetic resin material is characterized by first turning it into coarse particles, then turning it into fine particles, and then turning the coarse particles into fine particles in a state of reduced strength at high temperatures. A method for manufacturing an abrasive material according to claim 2.