JPH0261152B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an IC chip storage container that has excellent static electricity shielding properties and mechanical strength, and has a high degree of transparency. In recent years, electrical and electronic equipment products have become more dense and precise.
There has been a remarkable progress in miniaturization, and as a result, static electricity hazards that occur during parts manufacturing, assembly, storage, and transportation of semi-finished and finished products have become a major problem. Among these, IC (semiconductor integrated circuit) chips, especially MOS type IC chips, are susceptible to gate destruction due to even a small amount of static electricity, and can be destroyed by vibrations during storage or transportation or static electricity emitted from the worker's body. Because of the problem of quality products, storage containers for IC chips are required to have high static electricity shielding properties. Conventionally, the material used for storage containers for IC chips is thermoplastic resin that has been kneaded with conductive carbon black to provide antistatic properties.However, containers made of this material contain a large amount of carbon black. Due to the content, the inherent mechanical strength of the resin is impaired, and furthermore, since a black, opaque material is used, the content cannot be confirmed. On the other hand, IC chip storage containers that require particularly high transparency are made of transparent thermoplastic resin mixed with ion-conductive surfactants, but containers made of this material have antistatic properties. In particular, the surface resistivity is insufficient at 10 ¹² Ω or more, and the antistatic performance decreases temporarily due to wiping the surface, etc., and also decreases over time during use, so it is difficult to store IC chips. This has the disadvantage that it tends to increase the defective rate. Therefore, the present inventors conducted studies with the aim of obtaining an IC chip storage container that has high and long-lasting static electricity shielding properties, high mechanical strength, and excellent transparency. The inventors have discovered that the above object can be effectively achieved by using a composition comprising a modified polyester and an additive system, and have thus arrived at the present invention. That is, the present invention is based on (A) 100 parts by weight of modified polyethylene terephthalate obtained by copolymerizing polyethylene terephthalate with 1 to 20% by weight of polyalkylene glycol having a molecular weight of 1000 to 10000, (B) general formula Ar-SO ₃ 1/mMe (In the formula, Ar is an aromatic residue with or without a substituent, m is an integer of 1 to 3, and Me is a metal atom.) At least one sulfonic acid metal salt 0.01 to 10 The present invention also provides an IC chip storage container formed by molding a composition containing 0 to 500 parts by weight of polyethylene terephthalate (C). The IC chip storage container of the present invention is made of modified polyethylene terephthalate, which itself is transparent and has improved conductivity, and a small proportion of a conductivity-improving additive (B).
The modified component and additive (B) are further diluted with unmodified polyethylene terephthalate (C) as necessary.
The excellent transparency and mechanical strength of polyethylene terephthalate itself are suitably maintained, and the electrostatic shielding performance is improved to, for example, a surface resistivity of 10 ¹¹ Ω or less, and the sustainability of this electrostatic shielding performance is also excellent. demonstrate. Modified polyethylene terephthalate (A), which is the container constituent material of the present invention, is polyethylene terephthalate, that is, 80 mol% or more of the dicarboxylic acid component is terephthalic acid (or its ester-forming derivative), and 80 mol% or more of the diol component is ethylene. Obtained by adding 1 to 20% by weight, preferably 3 to 10% by weight of polyalkylene glycol having a molecular weight of 1000 to 10000, preferably 2000 to 6000, during polymerization of thermoplastic polyester that is glycol (or its ester-forming derivative). It is a so-called copolymerized block polyether ester. Examples of the polyalkylene glycol having a molecular weight of 1,000 to 10,000 include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, copolymers thereof, and methoxypolyethylene glycol. If the molecular weight of these alkylene glycols is less than 1,000, the effect of improving the electrostatic shielding properties of the molded article will be insufficient, and if it is more than 10,000, transparency will decrease, which is not preferable. In addition, modified polyethylene terephthalate (A) includes
Each of its dicarboxylic acid component and diol component
Isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis(p-carboxyphenyl)methane, within a range of 20 mol% or less and does not impair transparency.
Aromatic dicarboxylic acids such as anthracene dicarboxylic acid and 4,4'-diphenyl ether dicarboxylic acid; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and dodecanedioic acid;
Other dicarboxylic acid components such as alicyclic dicarboxylic acids such as 3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid or their ester-forming derivatives, and propylene glycol, 1,4-butanediol, neopentyl glycol, 1 , 5-pentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexanediol, or other diol components such as ester-forming derivatives thereof can be copolymerized. The copolymerization amount of polyalkylene glycol, which is a modification component of modified polyethylene terephthalate (A), greatly affects the effect of the present invention, and if it is less than 1% by weight, the effect of improving static electricity shielding property is insufficient;
If it is more than that, the transparency of the container will be significantly lowered, which is not preferable. The sulfonic acid metal salt (B) used as the conductivity improving additive in the present invention is represented by the above general formula, and specific examples include the following, among which it is preferable to use sodium alkylbenzenesulfonate.

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[Production of modified polyethylene terephthalate (A ₁ ) to (A ₅ )]

(A ₁ ) 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, and 1.9 parts of polyethylene glycol having a molecular weight of 4000 were placed in a polymerization can, and polymerization was carried out according to a conventional method. The resulting modified polyethylene terephthalate (PET) (A ₁ ) contains 2.0% polyethylene glycol. (A ₂ ) 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, and 9.8 parts of polyethylene glycol with a molecular weight of 4000 were placed in a polymerization can (A ₁ ).
Polymerization was carried out according to a conventional method. Obtained modified PET
( _A2 ) contains 10% polyethylene glycol component
include. (A ₃ ) 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, and 24.6 parts of polyethylene glycol having a molecular weight of 4000 were placed in a polymerization vessel and polymerized according to a conventional method. Modified PET (A ₃ ) contains 25% polyethylene glycol component (for comparison). (A ₄ ) 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, 4.9 parts of polyethylene glycol having a molecular weight of 4000, and 4.9 parts of sodium dodecylbenzenesulfonate were placed in a polymerization vessel and polymerized by a conventional method. The obtained modified PET (A ₄ ) contains 5% each of polyethylene glycol and sodium dodecylbenzenesulfonate. (A ₅ ) Polymerization was carried out in the same manner as in (A ₄ ) except that the polyethylene glycol with a molecular weight of 20,000 was used in (A ₄ ). the resulting denaturation
PET (A ₅ ) contains 5% each of polyethylene glycol and sodium dodecylbenzenesulfonate.
Including (for comparison). Examples 1 to 9 and Comparative Examples 1 to 7 Various (A) modified PET, (B) sodium dodecylbenzenesulfonate (DBS) and (C) unmodified PET,
They were mixed in the proportions shown in Table 1 and kneaded into chips using an extruder set at 280°C. From the chips obtained
Width 100 x length 150 x depth using 2.5OZ injection molding machine
A tray of 15 mm and 2.0 mm thickness was molded. The electrical properties and transparency of a test piece cut out from the bottom of the molded product were measured. The results are shown in Table 1.

[Table] As is clear from Table 1, the containers made of the two-component compositions (Examples 1 to 4) and the three-component compositions (Examples 5 to 9) of the present invention have good electrostatic shielding properties and transparency. Good balance. On the other hand, when additive (B) is missing (Comparative Example 1) and when unmodified PET is used alone (Comparative Example 7), the static electricity shielding properties are extremely poor, and when the amount of additive (B) added is 10 parts or more ( Comparative Example 2) shows a significant decrease in transparency. Also, unmodified in ternary compositions.
When the blending amount of PET (C) is too large (Comparative Example 3), the static electricity shielding property decreases, and when using modified PET (A ₃ ) with a polyalkylene glycol copolymerization amount of 20% or more (Comparative Examples 4 to 6). ) cannot satisfy transparency. Examples 10 to 13, Comparative Examples 8 to 11 Chips of modified PET (A ₄ ) and (A ₅ ) to which sodium dodecylbenzenesulfonate was added during polymerization and unmodified PET (C) were blended in the proportions shown in Table 2. , directly using 2.5OZ injection molding machine, width 100×
A tray with a length of 150 mm, a depth of 15 mm, and a thickness of 2.0 mm was molded. The bottom of the molded product was cut out and its electrical properties and transparency were measured. The results are shown in Table 2.

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[Table] As is clear from Table 2, the container of the present invention (Example
10 to 13) satisfies electrostatic shielding properties and transparency in a balanced manner. On the other hand, when the blending amount of unmodified PET to modified PET (A ₄ ) is too large (Comparative Example 8), the static electricity shielding property decreases, and modified PET (A ₅ ) modified with polyethylene glycol whose molecular weight is too large (20,000) is used. In the cases (Comparative Examples 9 to 11), the transparency was not satisfied. Example 14 Modified PET (A ₁ ) with the same formulation as shown in Example 3
100 parts of DBS and 10 parts of DBS were mixed in a tumbler, and a 30φ extruder was equipped with a modified die to form a square tube of 5×6 mm and 0.5 mm in wall thickness by direct extrusion molding. This tube was cut to a length of 150 mm and filled with 100 MOS type IC chips, and when viewed from the outside it was clearly visible that each chip had been inserted one by one. In this state, the amplitude is 3cm, the period is 2 times/sec
After applying vertical vibration for 3 hours, the IC chips were taken out and the failure rate was checked, and not a single chip was found to be damaged. Example 15 A MOS mold was added to the tray molded product obtained in Example 9.
Packed with 50 LSIs using IC chips, the amplitude is 1cm.
After applying horizontal vibration with a period of 10 times/sec for 1 hour, the LSI
When we checked the defective rate, not a single piece was found to be damaged. Example 16 Using the same recipe as Example 12, 100 parts of modified PET (A ₄ ) and 250 parts of polyethylene terephthalate resin were mixed in a tumbler, and molded directly with a 2.0OZ injection molding machine to form a product of 5 x 6 mm, wall thickness of 0.5 mm, and length. A 150 mm square tube-shaped molded product was obtained. Similar to Example 14, MOS type IC
When we packed 100 chips and observed them from the outside, we found that they were so transparent that we could see each one inside.
The same process as in Example 14 was carried out to check the defective rate of the IC chips, and all were found to be normal.

Claims (1)

[Claims] 1. (A) Polyethylene terephthalate has a molecular weight of
1 to 1000 to 10000 polyalkylene glycol
For 100 parts by weight of modified polyethylene terephthalate copolymerized with 20% by weight, (B) general formula Ar-SO ₃
1/mMe (wherein Ar is an aromatic residue with or without a substituent, m is an integer of 1 to 3, Me
1. An IC chip storage container formed by molding a composition containing 0.01 to 10 parts by weight of at least one sulfonic acid metal salt represented by (represents a metal atom) and 0 to 500 parts by weight of polyethylene terephthalate (C).