JPH09123182A - Resin composition tablet for mold cleaning - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the defective ratio and weight irregularity without lowering the cleaning effect of a mold cleaning resin composition. SOLUTION: The mold cleaning resin composition tablet removes the dirt of the mold surface at the time of molding curable resin molding material, and comprises the remolding of mixture of resin composition particles (A) having 70wt.% or more of particles which do not pass a 42-mesh sieve and resin composition powder (B) made of powder having 90wt.% or more of particles which pass 80-mesh sieve. The weight ratio of the particle (A)/powder (B) is 7/3 or more. The resin tablet is for cleaning multi-plunger mold. The resin composition contains 50ppm or less of sodium ion and 500ppm or less of potassium ion, and 200ppm or less of chlorine ion.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mold surface cleaning resin composition tablet for removing dirt on the mold surface during molding of a curable resin molding material, which has a good mold cleaning effect. The present invention also relates to a resin composition tablet for mold cleaning, which is dense and does not lose its shape.

[0002]

2. Description of the Related Art When molding a molded encapsulation product such as an integrated circuit made of a curable resin such as an epoxy resin, the inner surface of the mold becomes dirty if molding is continued for a long time, and if molding is continued continuously, the molding will be sealed. In many cases, the molding operation could not be continued because the surface of the molded product became dirty or the sealed molded product adhered to the mold. Therefore, it is necessary to regularly clean the mold, and a method has been proposed in which a mold cleaning resin is molded at a rate of several shots every several hundred shots of molding material to clean the mold.

For example, Japanese Examined Patent Publication No. 52-788 discloses that "molding of a curable resin molding material (excluding amino resin molding material) on the surface of a mold is molded with a material mainly composed of an amino resin. A cleaning method "has been proposed, and a mold cleaning resin composition comprising an amino resin, an organic base material and / or an inorganic base material, and a release agent is disclosed. Japanese Patent Publication No. 64-10162 discloses a mold cleaning resin composition containing 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.

Usually, the molding of an encapsulation molding such as an integrated circuit with a curable resin such as an epoxy resin is carried out by preforming the curable resin for encapsulation into a tablet shape and preheating the tablet at the time of molding. It is inserted into a pot and molded by transfer molding. Since the mold cleaning resin composition is applied by molding under the same conditions during molding of the curable resin for sealing, it is transfer molded in the same manner as molding of a normal epoxy resin for sealing, and a molding material. It is often used in a tablet shape of the same size as, and by preheating the tablet so that it softens and then molding, the mold cleaning resin composition is filled in the mold as a whole, and the mold surface becomes dirty during curing. The mold surface is cleaned by taking in.

Transfer molding methods include plate molding and multi-plunger molding. The plate mold uses one relatively large resin tablet per mold and is designed to minimize the number of runners in the mold and maximize the number of mold cavities. Each cavity has a structure in which one pot is branched at the shortest distance. The multi-plunger mold limits the number of cavities per transfer ram to a small number to minimize the runner, and has a large number of transfer rams. A small tablet is automatically set on each ram at the same time. It is preheated and transfer molded inside.

With the high integration, thinning, and surface mounting of ICs and LSIs, the diversification of molded products has progressed, and tablets of various sizes have been used in correspondence with each molded product. Therefore, the resin composition for mold cleaning is required to have tablets of various shapes corresponding to the resin tablets for epoxy resin encapsulation. In the transfer molding of a plate mold using a large-sized mold of several tens to several hundreds, a tablet having a diameter of about 30 to 70 mm is provided as a conventional type.

[0007] In response to the demand for unmanned molding and cleanliness, an automatic molding machine for curable resin has been developed, and automation of molding has been widely performed. This automatic molding machine is an IC / LSI. Is used to mold several sealed objects such as a multi-plunger mold, and the sealing resin used is supplied as a mini tablet with a diameter of about 5 to 30 mm. Also, a mini tablet having the same size and a diameter of about 5 to 30 mm is used.

[0008]

Therefore, Japanese Patent Publication No. 52-
It is generally practiced to tablet a conventionally known resin composition for mold cleaning as disclosed in Japanese Patent No. 788, and to use it for cleaning the mold. However, when tableting these mold cleaning resin compositions with a tablet molding machine, in many cases a super steel material or the like is used in the tablet molding mold to avoid mold wear, and the molded tablet is formed. Since it is more difficult to pull out than the mold, it is necessary to apply high pressure during withdrawal, and defects such as squeaking noise, cracking, and chipping are 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 mold cleaning resin composition to improve the tableting yield. However, if the content of the lubricant is increased, the lubricant itself may bleed and cause contamination of the mold,
The effect of cleaning the mold is significantly reduced, and the number of shots for cleaning the mold is increased. When a tablet is molded from the mold cleaning resin composition, since the resin composition is usually obtained in the form of powder, it is usual to charge the powder into a tablet molding machine and mold it. It was

However, the powder has a small apparent density, a large pressure is required when a tablet is formed from the powder, the obtained tablets also have a large variation in weight, and moreover, they are very large to be removed from the mold. It required high pressure and had a high defect rate such as cracking and chipping. In particular, there has been a demand for a tablet having good tablet moldability, good cleanability, and no 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 mold cleaning resin composition as a means for increasing the tableting yield without increasing the lubricant content. By using a mixture of particles having a particle size of 1 and a powder having a specific particle size and molding the mixture, it was found that tabletability is improved while maintaining good cleanability, and to complete the present invention. Only

That is, the present invention provides a mold-cleaning resin composition tablet for removing dirt on the surface of a mold at the time of molding a curable resin molding material, wherein the resin tablet contains particles that do not pass through a 42-mesh sieve. A remolded mixture of resin composition particles (A) having 70% by weight or more of particles and resin composition powder (B) having 90% by weight or more of particles having a particle size of 80 mesh. A resin composition tablet for mold cleaning, wherein the weight ratio of particles (A) / powder (B) is 7/3 or more, wherein the tablet diameter is less than 30 mm, and the multi-plunger mold is used. Is a resin composition tablet for cleaning a mold used for cleaning of a resin composition, wherein sodium ion in the resin composition is 5
00ppm or less, potassium ion 500ppm or less,
Moreover, it is the said resin composition tablet for mold cleaning which has a chlorine ion of 200 ppm or less.

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

Further, the resin composition particles (A) in the present invention are obtained by granulating the above resin composition powder (B), and the granulation is not particularly limited, but typically,
It is obtained by molding a powder into a tablet and crushing the tablet to a desired particle size, and the particle size is 70% by weight or more, preferably 75% by weight, of particles which do not pass through a 42 mesh sieve.
The above content, and more preferably 80% by weight or more.

The tablet forming material of the present invention comprises a mixture of the above-mentioned particles (A) and the above-mentioned powder (B), and the ratio of the particles (A) / the powder (B) is 7 /. When the amount of the powder (B) is more than the above range, the yield rate of tablets and the variation in weight of the obtained tablet are large, and when the amount of the particles (A) is large, the amount of the material to be granulated is large, There are many things that are used for retableting, which is not economically feasible. The range is preferably 8/2 or more, more preferably 8/2 to 9/1.

The amino resin composition in the present invention means
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 includes triazines such as melamine, phenols, formaldehyde and the like. The melamine-urea co-condensation resin is co-condensed from aldehydes, and is a co-condensed triazines such as melamine, ureas, and aldehydes such as formaldehyde.

The melamine resin is obtained by condensing triazines such as melamine and aldehydes, and the urea resin is obtained by condensing ureas and aldehydes. It is a thing. The triazine may contain, in addition to melamine, 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 above-mentioned phenols, in addition to phenol, relative to 100 parts by weight of the phenol,
For example, 30 parts by weight or less of phenols other than phenol such as cresol, xylenol, and ethylphenol butylphenol may be contained.

Furthermore, the resin composition used in the present invention includes
Subsequent amounts 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 resins include alkyd resins, polyester resins, acrylic resins, epoxy resins, rubbers and the like.

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, and examples thereof include calcium stearate, zinc stearate and zinc myristate. It is illustrated. These metal soaps are 0.1 to 1.5 parts by weight, preferably 0.2 to 1 part by weight, relative to 100 parts by weight of the mold cleaning resin composition.
It is particularly preferable to add 0.3 to 0.8 parts by weight. When the amount of metal soap is insufficient, cleaning resin does not reach even a minute portion of a complicated mold, resulting in insufficient cleaning and defective cleaning due to defective release of the cured cleaning resin.

In the present invention, a fatty acid amide type lubricant, a fatty acid type lubricant, an alcohol type lubricant, a paraffin type lubricant, a silicone type lubricant or the like can be further added to the resin composition. As the fatty acid amide type lubricant, , Saturated or unsaturated monoamide type lubricants such as lauric acid amide, myristic acid amide, erucic acid amide, oleic acid amide, stearic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebisoleic acid amide Examples of such saturated or unsaturated bisamide type lubricants include fatty acid type lubricants such as stearic acid and butyl stearate, alcohol type lubricants such as cetyl alcohol, and silicone type lubricants such as silicone oil. Etc. These various lubricants are combined with the above-mentioned metal soap-based lubricants, and the resin composition 10 for mold cleaning is used.
0.1 to 1.5 parts by weight, preferably 0.2 to 0.8 parts by weight, and particularly preferably 0.2 to 0.6, relative to 0 parts by weight.
It can be added in the range of parts by weight.

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

The particle size of the above-mentioned mineral powder is not particularly limited, but it is generally # 10 to # 8000, preferably #.
50 to # 4000, more preferably # 100 to # 200
It is in the range of 0. If the particle size is smaller than # 8000, the cleaning effect will be poor, dust will be generated during handling, and the working environment will be deteriorated, and other defects will easily occur. If the particle size is larger than # 10, mold damage, 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, and further 100 parts by weight of the mold cleaning resin composition of the present invention. It is preferably in the range of 17 to 29 parts by weight.

In addition to the above-mentioned mineral powder, the composition of the present invention may contain other additives such as other inorganic or organic fillers, colorants, curing catalysts and antioxidants. 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, red iron oxide, phthalocyanine-based, azo-based, diazo-based organic pigments, benzoxazole-based,
Coloring agents such as naphthotriazole-based, comarin-based fluorescent pigments, anthraquinone-based, indico-based, azo-based dyes; organic such as benzoic acid, phthalic anhydride, oxalic acid, sulfamic acid, paratoluenesulfonic acid Acids, inorganic acids such as hydrochloric acid, sulfuric acid, these acids and triethylamine,
Curing catalysts such as salts with triethanolamine, β-dimethylaminoethanol, 2-methyl-2-amino-1-propanol and the like; antioxidants such as naphthylamine antioxidants and thiobisphenol antioxidants Can be mentioned.

As the pulp, straw pulp, bamboo pulp, wood pulp (softwood pulp, hardwood pulp), etc. may be used, and either chemical pulp or mechanical pulp may be used. The size of the cellulose filler such as pulp and wood flour is not particularly limited, but generally 5 to 10
The range is 00 μm, 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 mold cleaning resin composition tablet contains sodium ions of 500 ppm or less, potassium ions of 500 ppm or less, and chlorine ions of 200 pp.
It is preferably m or less. That is, when cleaning the mold surface of the transfer mold molding die by the mold cleaning resin composition tablet, ionic impurities contained in the cleaning sheet remain on the mold surface,
This is because these ionic impurities may enter into the semiconductor element to be molded, and if the above ionic impurities enter into these semiconductor elements, a serious problem occurs in terms of corrosiveness. Therefore, in the production of the mold cleaning resin composition tablet, it is desirable to carefully examine the raw materials used and use the one that does not contain the above ionic impurities.

In the preparation of the composition of the present invention, an amino resin, a mineral powder, and, if desired, other secondary amounts of resin,
Any means capable of uniformly mixing the additives can be adopted.
For example, a kneader, a ribbon blender, a Henschel mixer, a ball mill, a roll kneading machine, a raker machine, a tumbler, etc. can be exemplified. The composition thus obtained is molded into tablets. The shape of the tablet can be various shapes depending on the structure of the mold such as cylindrical, rectangular, rod-shaped, rectangular parallelepiped, etc., but a cylindrical curable resin tablet for sealing is used for the semiconductor sealing mold. In this case, the mold cleaning resin composition tablet having the same shape is also used.

Usually, the above-mentioned powder / particle mixture of the resin composition for mold cleaning is put into a vertical or horizontal mold, and the plunger is mechanically or hydraulically pressurized to give powder / particle mixture.
Allow the particle mixture to solidify. The tablet forming pressure varies depending on the structure of the tablet machine, the diameter of the tablet, the height, etc., but is 200 to 1500 kg / cm ² , preferably 3
The range is from 00 to 1200 kg / cm ² .

Before tablet molding, additives such as lubricants may be added to the powder particle mixture of the resin composition for mold cleaning within a range not impairing the cleaning property. The post-added lubricant is present at a high concentration at the powder / particle interface and can improve tablet escape from the mold. The density of the tablet varies depending on the molding pressure of the composition, but is approximately 1.1 to 1.8 g / c.
It is in the range of m ³ .

The curable resin molding material capable of cleaning the mold using the composition of the present invention is, for example, an epoxy resin molding material, a phenol resin molding material or the like, preferably an epoxy resin molding material, particularly preferably Is an epoxy resin molding material for semiconductor encapsulation. Further, as the mold to which the mold cleaning resin composition 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, but in general, iron, chromium It can be suitably applied to a mold made of Particles (A) having the composition of the invention
The tablet obtained by re-molding from the mixture of the powder and the powder (B) can improve the yield of the tablet without lowering the mold cleaning effect.

[0030]

[Examples] Hereinafter, the mold composition example tablet of the present invention will be described in more detail with reference to Examples including Comparative Examples. In the following examples, the test method and evaluation are as follows. (1) Method of Testing Cleaning Effect A commercially available epoxy resin molding material (Nitron MP manufactured by Nitto Denko Corporation; trade name) was used to mold a sealed molding of an electronic circuit by transfer molding. After 400 shots molding, a test mold cleaning resin composition tablet having the same shape as the above material is molded with the mold, and the number of shots and the cleaning effect are investigated. Judgment of the cleaning effect was based on the following five-level judgment criteria by visual inspection.

5: No cloudiness, etc. 4: 〃 Almost none 3: Some cloudiness, 2: Cloudy cloudy 1: Many stains, and defective parts on the molded product

(2) Particle size measuring method The particle size is defined according to 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 Tablet mold (14 mmφ × 22.5 mmH)
Equipped with a tablet molding machine adjusted to a tablet weight of 4.5 g, the predetermined material is put into the supply hopper, and the pressure is increased to 350 kg / cm ² by a pressure device, and the pressure is about 1 Hold for minutes to mold. After molding, remove the lower part of the mold, read the maximum pressure (maximum pressure value) when pressing the tablet out, and observe whether there is a defect such as tablet damage (cracking, chipping). Similarly, 1
00 tablets were molded, the defective rate was calculated, the weight was measured, and the case where the weight variation was within 4.5 ± 0.45 g was designated as ◯.

<Tablet Reforming Material> Melamine 343
Parts by weight and 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 reaction vessel equipped with a stirrer, and 190 parts by weight of the resulting melamine-phenol co-condensed resin liquid and 50 parts by weight of pulp are kneaded in a kneader. 30 parts by weight of a resin compound obtained by drying, crushing, crushing, crushed by Nikaresin 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 benzoin. Acid 0.1 part by weight, zinc myristate 0.
5 parts by weight were added and mixed and pulverized by 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 mold a tablet, and the tablet is crushed into a required particle size by a tablet crusher to clean a mold. Resin composition particles (A)
I got Physical properties (apparent specific gravity and particle size distribution) of a tablet molding material composed of a mold cleaning resin composition powder, mold cleaning resin composition particles, and a tablet molding mixture of these powders and particles in a desired ratio. Was measured, and the obtained results are shown in Table 1.

[0036]

[Table 1]

(Examples and Comparative Examples) Table 1 shows a tablet forming machine equipped with a tablet forming die having a diameter of 14 mmφ, the tablet forming machine being adjusted so that the tablet weight becomes 4.5 g. The tablet remolding material is put into the supply hopper, and 350 kg /
A tablet was formed by pressurizing to cm ² and maintaining the pressure for about 1 minute. Table 2 shows the results obtained by measuring the maximum value of pressure applied when the tablet was pulled out, the tablet failure rate, the weight variation, and the cleaning effect. Further, in the case of molding a tablet with only powder, 1.5 parts by weight or more of metal soap is required to reduce the defective rate to 5% or less, but 1.7 parts by weight of metal soap in Comparative Example 1 is required. This is shown as Comparative Example 8.

[0038]

[Table 2]

[0039]

As described above, a mold cleaning resin composition tablet is remolded from a mixture of the resin composition particles (A) and the resin composition powder (B) to obtain a mold cleaning resin. It was possible to provide a tablet with a low defect rate and a small variation in weight without reducing the cleaning effect of the composition.

Claims (2)

[Claims] 1. A mold cleaning resin composition tablet for removing dirt on the 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: A metal mold for re-molding a mixture of powder (B), a weight ratio of particles (A) / powder (B) of 7/3 or more, and for cleaning a multi-plunger mold. Mold cleaning resin composition tablet. Particles (A): 70% by weight of particles not passing through 42 mesh sieve
Particles which are above Powder (B): Powder in which 90% by weight or more of particles pass through a 80 mesh sieve 2. The sodium ion in the resin composition is 50.
The mold composition resin composition tablet according to claim 1, wherein the content is 0 ppm or less, the content of potassium ion is 500 ppm or less, and the content of chlorine ion is 200 ppm or less.