JPH09123184A - Resin composition for cleaning mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce the thin flash without reducing cleanability by incorporating filler containing predetermined wt.% of more of vegetable fiber having a predetermined μm of fiber length. SOLUTION: The resin composition for cleaning a mold contains fibrous vegetable fiber. As the vegetable fiber, cellulose or particularly timber pulp is suitably used. The timber pulp having a fiber length of 50 to 200μm of 50wt.% or more or preferably 70wt.% or more is suitably used. The vegetable fiber having a suitable length makes it possible to prevent the oozing out of resin content and to reduce the quantity of thin flash. The quantity of the vegetable fiber is 15 to 70 pts.wt. or preferably 20 to 60 pts.wt. per 100 pts.wt. of amino resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold cleaning resin composition for cleaning dirt on the surface of a mold in molding a curable resin molding material, and shows a good mold cleaning effect and a mold after cleaning. TECHNICAL FIELD The present invention relates to a resin composition for cleaning a mold, which causes less pollution.

[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, if the molding is continued for a long time, the inner surface of the mold becomes dirty, and if molding is continued continuously,
In many cases, the surface of the molded encapsulant was soiled or the molded encapsulant adhered to the mold and the molding operation could not be continued. Therefore, it is necessary to regularly clean the mold, and there has been proposed a method of cleaning the mold by molding a mold cleaning resin at a rate of several shots every several hundred shots of molding material.

For example, Japanese Examined Patent Publication No. 52-788 discloses that the mold surface stain at the time of molding a curable resin molding material (excluding an amino resin molding material) is molded with a material mainly composed of an amino resin. Therefore, a cleaning method "is proposed, and an amino resin, an organic base material and / or an inorganic base material,
A mold cleaning resin composition comprising a release agent is disclosed. Japanese Patent Publication No. 64-1622 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.

On the other hand, high integration and thinness of IC / LSI,
With surface mounting, the diversification of molded products is progressing, and various sizes of molds are used according to each molded product, so that molds with many fine and fine parts are also used became.

However, a conventionally known mold cleaning resin composition as described in Japanese Patent Publication No. 52-788 is applied to a mold of a thin molded product or a mold having a minute portion. When used, a resin cured product (hereinafter referred to as "thin burr") that sticks out of the cavity of the mold and is cured during molding.
However, after cleaning the mold, it breaks when the cured resin for cleaning is taken out of the mold, and remains particularly in the thin part of the mold or in the minute part,
In many cases, it became impossible to resume molding of the curable resin.

Therefore, after cleaning the mold, the remaining thin burr must be manually removed again. In the case of an automatic molding machine, the automatic molding must be interrupted. The efficiency was greatly reduced.

As a result of research conducted by the present inventors, the inventors have found that by specifying the length of the plant fiber filler, the occurrence of thin burrs can be reduced without lowering the cleaning property. Completed the invention.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems, and in a melamine-based resin composition for mold cleaning for removing dirt on the surface of a mold during molding of a curable resin molding material, The present invention relates to a melamine resin composition for mold cleaning containing a filler containing 50% by weight or more of a plant fiber having a fiber length of 50 μm to 200 μm.

Hereinafter, the present invention will be described in detail. The melamine-based resin composition in the present invention indicates a melamine resin, a melamine-phenol cocondensate, a melamine-urea cocondensate, or the like, and the melamine-phenol cocondensate is a triazine such as melamine or a phenol. , Aldehydes such as formaldehyde, and the like, and the melamine-urea cocondensation resin is obtained by cocondensing triazines such as melamine, ureas, and aldehydes.

The above melamine resin is obtained by condensing triazines such as melamine and aldehydes, and the urea resin is obtained by condensing ureas and aldehydes. As the triazines, in addition to melamine, 100% by weight of the triazines,
For example, 30% by weight or less of triazines other than melamine such as benzoguanidine and acetoguanamine may be contained.

The above-mentioned phenols include, in addition to phenol, 100% by weight of the phenol,
For example, 30 wt% or less of phenols other than phenol such as cresol, xylenol, ethylphenol and butylphenol may be contained. Further, the above-mentioned aldehydes may contain formaldehydes such as paraform and acetaldehyde in addition to formaldehyde.

The amount of aldehyde relative to 1 mol of the melamine resin monomer is 1.0 to 2.2 mol, preferably 1.3 to 1.9 mol, and particularly preferably 1.4 to 1.8 mol. Is. If the aldehyde content is too low, the productivity will be poor during melamine resin production. If the aldehyde content is too high, even a small amount of thin burr will easily break and contaminate the mold.

Furthermore, the resin composition used in the present invention can be blended with a secondary amount of other resins which can be blended with the resin composition in an amount which does not adversely affect the above-mentioned improving properties of the composition of the present invention. . Examples of such resins include alkyd resins, polyester resins, acrylic resins, epoxy resins, and rubbers.

The mold cleaning resin composition of the present invention contains fibrous plant fibers. Examples of the plant fiber include celluloses, particularly pulps, but straw pulp, bamboo pulp, wood pulp (softwood pulp, hardwood pulp) and the like are used, and either chemical pulp or mechanical pulp may be used. . Particularly, wood pulp is preferably used, and wood pulp having a fiber length of 50 μ to 200 μ is used in an amount of 50% by weight or more,
Preferably, those containing 70% by weight or more are suitably used. If there are many short fibers, the fibers will flow out from the cavity along with a thin burr. The amount of thin burrs increases as a whole. Also, even if the fiber length is 200μ or more,
Not only is the effect of suppressing the occurrence of thin burrs not so desired, but rather the flow of the molten resin and the filling property are reduced. A moderate length of vegetable fiber can prevent resin oozing and reduce the amount of thin flash. The amount of vegetable fiber is 100 parts by weight of the above-mentioned amino resin,
15 to 70 parts by weight, preferably 20 to 60 parts by weight
Parts by weight are commonly used.

The mold cleaning resin composition of the present invention contains a mineral powder in addition to the above-mentioned resin and vegetable fibers. For example, natural materials such as corundum, emery, garnet, silica stone and silicon, iron, titanium, sodium, calcium,
Oxides or carbides of magnesium, aluminum, chromium, boron and the like 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 is generally # 10 to # 8000, preferably #.
50-4000, more preferably # 100- # 2000
It is good. If the particle size is smaller than # 8000, the cleaning effect will be poor, and defects such as dust will be generated during handling and the working environment will be deteriorated. If the particle size is larger than # 10, the mold will be damaged and cleaning will be uneven. Is likely to occur.

The amount of the mineral powder used is not particularly limited, but the mold cleaning resin composition 1 of the present invention is used.
It is 10 to 90 parts by weight, preferably 10 to 30 parts by weight, relative to 00 parts by weight.

Furthermore, the mold cleaning resin composition of the present invention can be used as a lubricant, for example, metal soap such as zinc stearate, calcium stearate and zinc myristate, fatty acids such as stearic acid, oleic acid and behenic acid, and butyl stearate. Fatty acid esters such as oleic acid, dodecyl stearate, stearic acid monoglyceride, oleic acid monoglyceride, hydroxystearic acid monoglyceride, pentaerythritol stearic acid ester, polyglycerin stearate, sorbitan trioleate and other fatty acid partial esters, lauric acid amide, myristin Fatty acid amides such as acid amide, erucic acid amide, oleic acid amide, stearic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebisoleic acid amide It can be added fatty bisamides such as de like. To keep the mold cleanability good,
The total amount of lubricant is 1.5 parts by weight or less, preferably 1 part by weight or less, relative to 100 parts by weight of the mold cleaning resin composition.

The composition of the present invention comprises, in addition to the above-mentioned mineral powder, other inorganic or organic fillers, colorants, curing catalysts,
It may contain other additives such as antioxidants. Examples of such additives include, for example, glass powder, glass fibers, untreated calcium carbonate, talc, aluminum hydroxide, barium sulfate, other inorganic or organic fillers such as zinc sulfide; for example, titanium oxide, carbon. Inorganic pigments such as black, zinc white, cadmium yellow and red iron oxide, phthalocyanine-based, azo-based, diazo-based organic pigments, benzoxazole-based, naphthotriazole-based, comarine-based fluorescent pigments, anthraquinone-based, indico-based, azo Colorants such as dyes of the system; for example, organic acids such as phthalic anhydride, oxalic acid, sulfamic acid, paratoluenesulfonic acid, etc., inorganic acids such as hydrochloric acid, sulfuric acid, these acids and triethylamine, triethanolamine, β-dimethylamino Such as salts with ethanol, 2-methyl-2-amino-1-propanol, etc. Curing catalyst; e.g. naphthylamine antioxidants, p- phenylenediamine antioxidants, such as such as antioxidants thiobisphenol antioxidants and the like.

In preparing the composition of the present invention, any means capable of uniformly mixing the amino resin, the mineral powder, the resin of other sub-amounts, and the additives can be adopted. For example, kneader, ribbon blender, Henschel mixer,
Examples thereof include a ball mill, roll kneading machine, raker machine, and tumbler.

The curable resin molding material which can be used to clean 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 a semiconductor sealing material. It is an epoxy resin molding material for fixing. 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 automatically molding the cured resin molding material, but in general, iron, A mold made of chrome or the like can be applied.

The mold cleaning resin composition having the composition of the present invention can be used after molding into a tablet having the same size as the curable resin, if necessary.

[0023]

The present invention will be specifically described below with reference to examples. The cleaning effect and the thin burr formation state were measured by the following methods.

<Molding of resin composition tablet for mold cleaning> 5 g of raw material powder is weighed in a tablet molding mold (20 mmφ × 30 mmH) and pressurized to 350 Kgf / cm ² with a pressure device, and mold cleaning A resin composition tablet for use was molded.

<Cleaning effect test method> Using a commercially available epoxy resin molding material (Nitron MP manufactured by Nitto Denko Corporation) minitablet, a sealing molding product was molded with a die for an automatic molding machine to 40
After 0 shot transfer molding and contaminating the mold,
A test mold cleaning resin composition tablet was molded with the mold, and the number of shots and the cleaning effect were evaluated as follows. 5: No cloudiness, etc. 4: Almost no cloudiness, etc. 3: Some cloudiness, 2: Cloudy weather, 1: Many dirt

<Thin Burr Occurrence Test> After the cleaning effect test was completed, the mold was observed to observe the remaining state of thin burrs. ◯: Almost no thin burr remains Δ: Slight burr remains slightly in the corners ×: Thin burr remains and needs cleaning.

Example 1 A mixture of 343 parts by weight of melamine, 130 parts by weight of phenol, 517 parts by weight of formalin (37% aqueous solution) and 4 parts by weight of potassium hydroxide was reacted by heating, and a melamine-phenol co-condensation resin was prepared by a known method. 70 parts by weight of a liquid prepared and dried under reduced pressure to form powder, 20 parts by weight of silica powder having a particle size of # 200, 9.5 parts by weight of powder pulp having 72% by weight of a pulp having a length of 50 to 200 μ, and benzoic acid. 0.1 parts by weight and 0.5 parts by weight of zinc stearate crushed by a ball mill, and 0.3 parts by weight of ethylenebisstearic acid amide added by a Nauta mixer are resin compositions for mold cleaning. It was set to A. Table 1 shows the test results of the cleaning effect and the thin burr generation amount using the obtained mold cleaning resin composition. .

Example 2 190 parts by weight of the melamine-phenol co-condensation resin liquid obtained in Example 1 and 50 parts by weight of powder pulp having 65% by weight of pulp having a length of 50 to 200 μ are kneaded in a kneader. A melamine-phenol co-condensation resin compound was obtained by drying, then crushing. 30 parts by weight of this compound, 50 parts by weight of a commercially available melamine resin (Nikaresin S-176 manufactured by Nippon Carbide Industry Co., Ltd .; formaldehyde / melamine = 1.7 / 1 (molar ratio)),
20 parts by weight of silica powder having a particle size of # 200, 0.1 part by weight of benzoic acid and 0.5 part by weight of zinc myristate were added and ground in a ball mill to obtain 0.3 parts by weight of ethylenebisstearic acid amide. The resin composition B for mold cleaning was added with a mixer. Table 1 shows the test results of the cleaning effect and the thin burr generation amount using the obtained mold cleaning resin composition.

Example 3 Using 363 parts by weight of melamine, 87 parts by weight of urea, and 550 parts by weight of formalin (37% aqueous solution), a melamine-urea co-condensation resin liquid was prepared by a known method, dried under reduced pressure, and powdered. 60 parts by weight, 19.3 parts by weight of quartz powder having a grain size of # 1000, and a pulp having a length of 50 to 200 μ are 65 parts by weight.
20 parts by weight of powder pulp, which is 10% by weight, and phthalic anhydride of 0.
A resin composition C for mold cleaning was obtained by crushing 0.5 parts by weight of calcium stearate and 0.5 parts by weight of calcium stearate with a ball mill and adding 0.4 parts by weight of ethylenebisoleic acid amide with a Nauta mixer. did. Table 1 shows the test results of the tablet property, the cleaning effect, and the thin burr generation amount using the obtained mold cleaning resin composition.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the powdered pulp in Example 1 had a weight of 50 μm or less and 80% by weight was used to obtain a mold cleaning resin composition D. Obtained. Table 1 shows the test results of the cleaning effect and the thin burr generation amount using the obtained mold cleaning resin composition.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the powder pulp in Example 1 used was 80 wt% pulp having a length of 200 μm or more, to obtain a mold cleaning resin composition E. Obtained. Table 1 shows the test results of the cleaning effect and the thin burr generation amount using the obtained mold cleaning resin composition.

[0032]

[Table 1]

[0033]

As described above, the mold cleaning resin composition contains a filler containing 50% by weight or more of vegetable fibers having a fiber length of 50 μm to 200 μm to reduce the amount of thin burrs generated during cleaning. , Mold cleaning work can be done efficiently

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Claims (1)

[Claims] 1. A melamine-based resin composition for cleaning a mold for removing dirt on the surface of a mold during molding of a curable resin molding material, comprising a filler containing 50% by weight or more of a plant fiber having a fiber length of 50 μm to 200 μm. A melamine resin composition containing a mold for cleaning.