JP3270312B2 - Mold cleaning resin composition tablet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition tablet for cleaning a mold surface for removing dirt on the surface of a mold when molding a curable resin molding material, and has a good mold cleaning effect. The present invention relates to a resin cleaning tablet which is dense and does not lose its shape.

[0002]

2. Description of the Related Art In molding a molded article such as an integrated circuit using a curable resin such as an epoxy resin, if the molding is continued for a long time, the inner surface of the mold becomes dirty. In many cases, the molding operation cannot be continued because the surface of the molded product is soiled or the sealed molded product adheres to the mold. For this reason, it is necessary to periodically clean the mold, and a method of cleaning the mold by molding the mold cleaning resin at a rate of several shots every several hundred shots of the molding material has been proposed.

[0003] For example, Japanese Patent Publication No. 52-788 discloses that "a dirt on a mold surface during molding of a curable resin molding material (excluding an amino resin molding material) is molded with a material mainly composed of an amino resin. By doing so, a "cleaning method" has been proposed, and a resin composition for mold cleaning comprising an amino resin, an organic substrate and / or an inorganic substrate, and a release agent has been disclosed. JP-B-64-10162 discloses a resin composition for cleaning a mold, comprising a co-condensation resin of an amino resin and a phenol resin and a mineral powder having a new Mohs hardness of 6 to 15. ing.

[0004] Usually, the molding of a sealing molded product such as an integrated circuit using a curable resin such as an epoxy resin is performed by preliminarily molding the curable resin for sealing into a tablet shape, preheating the tablet at the time of molding. It is inserted into a pot and molded by transfer molding. Since the resin composition for mold cleaning is applied by molding under the same conditions during molding of the curable resin for encapsulation, transfer molding is performed in the same manner as molding of epoxy resin for ordinary encapsulation, and molding material is used. It is often used in the form of a tablet having the same size as the above, and by performing pre-heating so that the tablet is softened and then performing molding, the mold cleaning resin composition is filled in the entire mold, and stains on the mold surface during curing. By cleaning the surface of the mold, the surface of the mold is cleaned.

[0005] Transfer molding methods include a plate mold and a multi-plunger mold. The plate mold uses one relatively large resin tablet per mold and is designed to minimize the number of cavities in the mold by minimizing the number of runners and the like in the mold. Each of the cavities has a structure that branches off at the shortest distance around one pot. The multi-plunger mold has a small number of cavities per transfer ram to minimize the number of runners, and has a large number of transfer rams. The transfer molding is performed by preheating in the inside.

[0006] With the increasing integration, thinning, and surface mounting of ICs and LSIs, molded products have been diversified, and tablets of various sizes have been used for each molded product. Accordingly, tablets of various shapes are required for the resin composition for cleaning the mold, corresponding to the resin tablets for sealing the epoxy resin. In transfer molding of a plate mold using a large mold of several tens to several hundred pieces, a tablet having a diameter of about 30 to 70 mm is provided as a conventional type.

[0007] In response to demands for unmanned and clean molding, automatic molding machines for curable resins have been developed, and molding has been widely automated. Is molded by a multi-plunger mold of several to several tens of pieces, and the sealing resin to be used is supplied as a mini-tablet having a diameter of about 5 to 30 mm. Also, mini-tablets having the same size and a diameter of about 5 to 30 mm are used.

[0008]

SUMMARY OF THE INVENTION
It is common practice to form a conventionally known resin for mold cleaning as a tablet, as disclosed in Japanese Patent Publication No. 788, and use it for cleaning the mold. However, when these mold cleaning resin compositions are tableted with a tablet molding machine, a super-steel material or the like is often used for the tablet molding die in order to avoid mold abrasion. However, since it was difficult to remove from the mold, it was necessary to apply high pressure at the time of extraction, and squeaking noise, cracks, chipping, and other defects were likely to occur, and the defect rate was high.

Therefore, as exemplified in Japanese Patent Publication No. 52-788, attempts have been made to increase the lubricant content of the resin composition for cleaning a mold to improve the yield of tableting. However, when the content of the lubricant is increased, the lubricant itself bleeds and becomes a factor contaminating the mold,
The mold cleaning effect is significantly reduced, and the number of shots for cleaning the mold is increased. When a tablet is molded from the resin composition for mold cleaning, the resin composition is usually obtained in the form of a powder, so that the powder is usually charged into a tablet molding machine and molded. Was.

[0010] However, the powder has a small apparent density, requires a large pressure when forming a tablet from the powder, and the obtained tablet has a large weight variation, and is very difficult to remove from the mold. Required a high pressure, and the defect rate such as cracking and chipping was high. In particular, there has been a demand for a tablet having good tablet moldability, good cleanability, and free from molding defects such as cracks and chips.

[0011]

Means for Solving the Problems As a result of intensive studies, the present inventors have identified a resin composition for cleaning a mold as a means for improving the yield of tableting without increasing the content of lubricant. By using a mixture of particles having a particle size of and a powder having a specific particle size, and molding the mixture, it has been found that tabletability is improved while maintaining good cleaning properties, and the present invention has been completed. It was just.

That is, the present invention relates to a mold cleaning resin composition tablet for removing dirt on a mold surface at the time of molding a curable resin molding material, wherein the resin tablet has particles that do not pass through a 42 mesh sieve. A mixture of a resin composition particle (A) having a particle size of 70% by weight or more and a resin composition powder (B) having a particle size of 90% by weight or more having a particle diameter of 80 mesh is re-formed. And a tablet cleaning resin composition tablet having a weight ratio of particles (A) / powder (B) of 1/9 or more, wherein the tablet diameter is 30 mm or more, and The resin composition tablet for mold cleaning as described above, which is used for conventional cleaning and has a sodium ion content of 500 ppm or less and a potassium ion content of 500 ppm or less.
The above-mentioned resin composition tablet for mold cleaning, wherein the tablet composition has a ppm or less and a chlorine ion is 200 ppm or less.

Hereinafter, the present invention will be described in detail.
The resin composition for cleaning a mold of the present invention comprises an amino resin composition, and the resin contains a metal soap as a lubricant, a mineral powder, an inorganic or organic filler, and other additives. The components are mixed by any means capable of uniformly mixing to form a composition, and pulverized to obtain a resin composition powder (B).
The powder (B) in the present invention is a powder containing 90% by weight or more, preferably 93% by weight or more, more preferably 95% by weight or more of particles having a particle size of 80 mesh sieve.

The resin composition particles (A) of the present invention are obtained by granulating the above resin composition powder (B), and the granulation is not particularly limited.
A powder is formed into a tablet, and the tablet is obtained by pulverizing the tablet to a desired particle size. The particle size is 70% by weight or more, preferably 75% by weight, of particles not passing through a 42 mesh sieve.
The content is more preferably 80% by weight or more.

The tablet molding material of the present invention comprises a mixture of the above-mentioned particles (A) and the above-mentioned powder (B), and the ratio thereof, that is, particle (A) / powder (B) is 1 /. When the amount of the powder (B) is larger than the above range, the defective rate and weight variation of the obtained tablet increase, and when the number of the particles (A) is large, the amount of the material to be granulated becomes large, There are many things to offer for re-tabletting, which is not economically feasible. The range is preferably 2/8 to 8/2,
More preferably, it is in the range of 3/7 to 7/3.

The amino resin composition of the present invention is
A melamine resin, a urea resin, a melamine-phenol co-condensation resin or a melamine-urea co-condensation resin and a mixture thereof, wherein the melamine-phenol co-condensation resin is a triazine such as melamine, a phenol, a formaldehyde or the like. The melamine-urea co-condensation resin is obtained by co-condensing aldehydes such as triazines such as melamine and ureas and formaldehyde.

The melamine resin is obtained by condensing a triazine such as melamine and an aldehyde, and the urea resin is obtained by condensing a urea and an aldehyde. Things. In addition to the melamine, the triazine may contain, for example, 30% by weight or less of triazines other than melamine such as benzoguanidine and acetoguanamine based on 100 parts by weight of the triazine. As the phenols, in addition to phenol, 100 parts by weight of the phenol,
For example, phenols other than phenol such as cresol, xylenol, and ethylphenol butylphenol may be contained in an amount of 30 parts by weight or less.

Further, the resin composition used in the present invention includes:
A secondary amount of other resins that can be blended therewith can be blended within a range that does not adversely affect the improved properties of the composition of the present invention as the mold cleaning resin composition.
Examples of such a resin include an alkyd resin, a polyester resin, an acrylic resin, an epoxy resin, and rubbers.

The metal soap used in the present invention is involved in improving the fluidity of the molten resin in the mold and the releasability after the resin is cured. For example, calcium stearate, zinc stearate, zinc myristate and the like are used. Is exemplified. These metal soaps are 0.1 to 1.5 parts by weight, preferably 0.2 to 1 part by weight, based on 100 parts by weight of the resin composition for mold cleaning.
It is particularly preferable to add 0.3 to 0.8 parts by weight. Insufficient metal soap causes insufficient cleaning because the cleaning resin does not spread to minute parts of the complicated mold, and poor cleaning due to poor release of the cured cleaning resin.

In the present invention, the resin composition further comprises a fatty acid amide lubricant, a fatty acid lubricant, an alcohol lubricant, and a paraffin lubricant. A lubricant such as a silicone lubricant can be added. Examples of the fatty acid amide lubricant include saturated or unsaturated monoamides such as lauric amide, myristic amide, erucamide, oleic amide and stearamide. Type lubricants, saturated or unsaturated bisamide type lubricants such as methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebisoleic acid amide, and the like. Examples of fatty acid type lubricants include stearic acid and butyl stearate. Examples of the alcohol-based lubricant include cetyl alcohol, and examples of the silicone-based lubricant include silicone oil. These various lubricants can be used in combination with the above-mentioned metal soap-based lubricants in combination with the mold cleaning resin composition 10.
0.1 to 1.5 parts by weight, preferably 0.2 to 0.8 parts by weight, particularly preferably 0.2 to 0.6 parts by weight with respect to 0 parts by weight.
It can be added in the range of parts by weight.

In order to maintain good mold cleaning properties, the total amount of the lubricant is preferably 1.5 parts by weight or less, more preferably 100 parts by weight, with respect to 100 parts by weight of the amino resin composition for mold cleaning. It is better to use 1 part by weight or less. The resin composition for cleaning a mold of the present invention contains a mineral powder in addition to the resin described above. For example, natural materials such as corundum, emery, garnet, silica stone and silicon, iron, titanium, calcium, magnesium, aluminum, chromium, boron,
And the like, and oxides and carbides thereof are preferable. Examples of these compounds include silicon oxide, magnesium oxide, aluminum oxide, silicon carbide, and boron carbide.

The particle size of the mineral powder is not particularly limited, but is generally from # 10 to # 8000, preferably from # 10 to # 8000.
50 to # 4000, more preferably # 100 to # 200
It is in the range of 0. When the particle size is smaller than # 8000, the cleaning effect is deteriorated, dust is generated during handling, and disadvantages such as deterioration of the working environment are likely to occur. When the particle size is larger than # 10, damage to the mold, uneven cleaning, etc. Defects are likely to occur. The amount of the mineral powder used is not particularly limited, but is 10 to 90 parts by weight, preferably 15 to 30 parts by weight, more preferably 100 parts by weight based on 100 parts by weight of the resin composition for mold cleaning of the present invention. Preferably it is in the range of 17 to 29 parts by weight.

The composition of the present invention may contain other additives such as inorganic or organic fillers, coloring agents, curing catalysts, antioxidants, etc., in addition to the above-mentioned mineral powder. Good. Examples of such additives include, for example, pulp, wood flour,
Vinylon fiber, glass powder, glass fiber, untreated calcium carbonate, talc, aluminum hydroxide, barium sulfate,
Other inorganic or organic fillers such as zinc sulfide;
Inorganic pigments such as titanium oxide, carbon black, zinc white, cadmium yellow and red iron, phthalocyanine-based, azo-based, diazo-based organic pigments, benzoxazole-based,
Coloring agents such as naphthotriazole-based, comarine-based fluorescent pigments, and anthraquinone-based, indico-based, and azo-based dyes; for example, organic acids such as benzoic acid, phthalic anhydride, oxalic acid, sulfamic acid, and paratoluenesulfonic acid. Acids, hydrochloric acid, inorganic acids such as sulfuric acid, these acids and triethylamine,
Curing catalysts such as salts with triethanolamine, β-dimethylaminoethanol, 2-methyl-2-amino-1-propanol; and antioxidants such as naphthylamine-based antioxidants and thiobisphenol-based antioxidants. Can be mentioned.

As the pulp, straw pulp, bamboo pulp, wood pulp (conifer pulp, hardwood pulp) and the like may be used, and any of chemical pulp and mechanical pulp may be used. The size of the cellulose filler such as pulp and wood flour is not particularly limited.
The range is preferably 00 μm, and more preferably 10 to 200 μm.
The amount of cellulose added is 15 to 70 parts by weight, preferably 20 to 60 parts by weight, based on 100 parts by weight of the amino resin.
It is in the range of parts by weight.

Further, the resin composition tablet for mold cleaning has a sodium ion of 500 ppm or less, a potassium ion of 500 ppm or less, and a chlorine ion of 200 pp.
m or less. That is, when the mold surface of the transfer mold molding die is washed by the mold cleaning resin composition tablet, ionic impurities contained in the cleaning sheet remain on the mold surface,
This is because there is a risk that these ionic impurities may enter the semiconductor element to be molded, and if the above-mentioned ionic impurities enter the semiconductor element, a serious problem occurs in terms of corrosiveness. Therefore, when manufacturing the resin composition tablet for mold cleaning, it is desirable to thoroughly examine the raw materials to be used and to use those which do not contain ionic impurities as described above.

In preparing the composition of the present invention, the amino resin, the mineral powder and, if desired, other secondary amounts of the resin,
Any means capable of uniformly mixing the additives can be employed.
For example, a kneader, a ribbon blender, a Henschel mixer, a ball mill, a roll mill, a grinder, a tumbler and the like can be exemplified. The composition thus obtained is formed into tablets. The tablet can be of various shapes such as cylinder, rectangle, rod, rectangular parallelepiped, etc. according to the mold structure. In this case, the resin composition tablet for cleaning the mold has the same shape.

Usually, the powder / particle mixture described above is placed in a vertical or horizontal mold, and the plunger is pressurized mechanically or by hydraulic pressure to form a powder / particle mixture. To solidify. The tablet forming pressure varies depending on the structure of the tablet machine, the tablet diameter, the height and the like, but is 200 to 1500 kg / cm ² , preferably 30
The range is from 0 to 1200 kg / cm ² . Prior to tablet molding, an additive such as a lubricant may be added to the resin composition powder particle mixture for mold cleaning within a range that does not hinder the cleanability. The post-added lubricant is present at a high concentration at the powder / particle interface,
The removal of the tablet from the mold can be improved.

The tablet density varies depending on the molding pressure of the composition, but is generally in the range of 1.1 to 1.8 g / cm ³ . Examples of the curable resin molding material capable of cleaning a mold using the composition of the present invention include an epoxy resin molding material and a phenol resin molding material, preferably an epoxy resin molding material, and particularly preferably a semiconductor sealing material. It is an epoxy resin molding material for stopping.

As the mold to which the resin composition for cleaning a mold of the present invention is applied, any mold can be used as long as it is a mold used for molding the curable resin material. It can be suitably applied to a mold made of iron, chromium, or the like.
The tablet having the composition of the present invention and obtained by re-molding from a mixture of the particles (A) and the powder (B) can improve the tablet yield without lowering the mold cleaning effect. .

[0030]

EXAMPLES Hereinafter, the tablet for the composition of the present invention for cleaning the mold according to the present invention will be described in more detail by way of examples including comparative examples. In the following examples, the test method and evaluation are as follows. (1) Test method of cleaning effect A sealed molded product of an electronic circuit was formed by transfer molding using a commercially available epoxy resin molding material (Nitron MP manufactured by Nitto Denko Corporation; tablet). After the 400 shots are formed, a test mold cleaning resin composition tablet having the same shape as the above-mentioned material is formed in the mold, and the number of shots and the cleaning effect are investigated. The judgment of the cleaning effect was based on the following five criteria based on visual observation. 5: There is no fogging etc. 4: 〃 Almost no 3: There is some fogging 2: There is fogging 1: A lot of dirt has a defective part in the molded product

(2) Measurement method of particle size The particle size is defined in accordance with JIS-R6001 (1973).
The measuring method was measured according to JIS-R6002. # As used herein is a number or mesh.

(3) Tablet property measuring method A tablet forming die (48 mmφ × 32 mmH) is provided, and a predetermined material is put into a supply hopper by a tablet forming machine in which the forming machine is adjusted so that the tablet weight becomes 75 g. Then, the pressure is increased to 1000 kg / cm ² by a pressure device, and the pressure is maintained for about 1 minute to perform molding. After molding, remove the lower part of the mold, read the maximum pressure (maximum pressure) when extracting the tablet by pressing, and break the tablet (crack, chipping)
Observe whether there is a defect such as. Similarly, 100
Each tablet was molded, its defect rate was calculated, its weight was measured, and those whose weight variation was within 75 ± 3 g (4%) were evaluated as ○.

<Tablet Reforming Material> Melamine 343
Parts by weight, 130 parts by weight of phenol and formalin (37%
(Aqueous solution) 517 parts by weight and 4 parts by weight of potassium hydroxide are heated and reacted in a reactor equipped with a stirrer, and 190 parts by weight of the obtained melamine-phenol cocondensation resin solution and 50 parts by weight of pulp are kneaded in a kneader. 30 parts by weight of a resin compound obtained by drying, drying and pulverizing, 50 parts by weight of Nicalen S-176 (trade name) manufactured by Nippon Carbide Industry Co., Ltd., 20 parts by weight of silica powder having a particle size of # 200, and benzoic acid Acid 0.1 parts by weight, zinc myristate 0.
5 parts by weight and mixed and pulverized with a ball mill to obtain a mold cleaning resin composition powder (B).

On the other hand, the resin composition powder obtained above is supplied to a hopper of a tablet molding machine to form a tablet, and the tablet is crushed to a required particle size by a tablet crusher, thereby cleaning the mold. Resin composition particles (A)
I got Physical Properties (Apparent Specific Gravity and Particle Size Distribution) of Mold Cleaning Resin Composition Powder, Mold Cleaning Resin Composition Particles, and Tablet Molding Material Consisting of Tablet Mixture in Desired Ratio of Powder and Particles Was measured, and the obtained results are shown in Table 1.

[0035]

[Table 1]

(Examples and Comparative Examples) A tablet molding machine equipped with a tablet molding die having a diameter of 48 mmφ was added to a tablet molding machine adjusted to have a tablet weight of 75 g by a tablet molding machine shown in Table 1 above. The molding material is put into the supply hopper, and 1000 kg /
The tablet was molded by pressurizing to ² cm ² and maintaining the pressure for about 10 seconds. The highest pressure value when extracting the tablet,
The tablet failure rate, weight variation, and cleaning effect were measured, and the results are shown in Table 2. When a tablet is formed from powder alone, 1.5 parts by weight or more of metal soap is required to reduce the defective rate to 5% or less. However, 1.7 parts by weight of metal soap in Comparative Example 1 is required. Is shown as Comparative Example 2.

[0037]

[Table 2]

[0038]

As described above, the resin composition for mold cleaning is remolded from the mixture of the resin composition particles (A) and the resin composition powder (B). Without reducing the cleaning effect of the composition, defective rate,
A tablet with less weight variation could be provided.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-123669 (JP, A) JP-A-58-113243 (JP, A) JP-A-59-126426 (JP, A) JP-A-3-3 81111 (JP, A) JP-A-8-57865 (JP, A) JP-A-5-131460 (JP, A) JP-B 64-10162 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 33/72

Claims (2)

(57) [Claims] 1. A mold cleaning resin composition tablet for removing dirt on a mold surface during molding of a curable resin molding material, wherein the resin tablet comprises the following resin composition particles (A) and the following resin composition Mold cleaning resin composition obtained by re-molding a mixture with the product powder (B), wherein the weight ratio of particles (A) / powder (B) is 1/9 or more, and which is for conventional use Things tablet. Particles (A): 70% by weight of particles not passing through a 42 mesh sieve
Powder (B): Powder having 90% by weight or more of particles passing through an 80 mesh sieve 2. The method according to claim 1, wherein the sodium ion in the resin composition is 50%.
The resin composition tablet for mold cleaning according to claim 1, wherein 0 ppm or less, potassium ion is 500 ppm or less, and chloride ion is 200 ppm or less.