JPH04323262A - Heat-resistant and electrically conductive resin composition - Google Patents

Abstract

PURPOSE:To obtain an inexpensive heat-resistant and electrically conductive resin composition, having high heat resistance, simultaneously excellent in strength, processability and dimensional stability and suitable as IC trays. CONSTITUTION:A heat-resistant and electrically conductive resin composition is obtained by using an inexpensive nylon 66 resin as a synthetic resin which is a substrate and blending mica powder in an amount of 5-40wt.% based on the total weight content for improving its heat resistance and simultaneously adding carbon black in an amount of 5-30wt.% based on the total weight content for imparting electric conductivity. Since the mica powder has a fear of incurring deterioration in processability and physical properties, mica powder having the surface treated with a silane coupling agent is used to improve the strength and dimensional stability of molded products. Furthermore, a low-molecular weight polyester-based liquid crystal resin in an amount of 0.5-10wt.% based on the total weight content is added to prevent the processability from deteriorating.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a resin composition that is based on nylon 66 resin, which is a crystalline thermoplastic resin, and has excellent heat resistance and impact resistance, and also has excellent processability. It relates to objects and is mainly used as raw material for trays used for storing and transporting semiconductor electronic components.

0002

2. Description of the Related Art Semiconductor electronic components (ICs) are often handled in thin grid-like trays (or pallets).

[0003] This IC tray is made by injection molding or vacuum forming a composition of polystyrene resin or polyvinyl chloride resin mixed with carbon black, etc., but it has low mechanical strength and dimensional accuracy. Because of this, many problems occur, such as inability to stably mount IC packages using automatic mounting machines.

On the other hand, as IC packages become more sophisticated and thinner, the proportion of wafer chips in the sealing resin increases.
As a result, if the sealing resin absorbs moisture, there is a problem that when heat is applied during soldering, the moisture evaporates and expands, causing cracks. Therefore, before performing surface mounting,
It has become necessary to remove moisture by performing a drying process at 125°C for about 24 to 48 hours, but since the above-mentioned composition has no heat resistance, the IC package is This has the disadvantage that the work efficiency is extremely low since it must be transferred to a heat-resistant tray. As a countermeasure against this problem, heat-resistant IC trays made of, for example, polybutylene terephthalate resin as a base material have been provided, but these have the problem of large warpage and deformation during use.

[0005] Furthermore, since IC trays are generally disposable, they need to be provided at a low price, and for this reason, it has been considered that a large amount of inorganic filler such as talc or mica powder is blended into an inexpensive base resin. However, it has the disadvantage of easily impairing processability and fluidity. In particular, injection molded IC trays are usually annealed at a temperature of about 130 to 170°C to stabilize their dimensions, but if the fluidity during molding is not good, internal stress generated during molding may be caused by annealing. Not only does this cause the problem that the IC tray becomes warped or distorted, but also the use of a large amount of inorganic filler lowers the impact resistance and makes it more likely to break.

[0006] In response to this, a polypropylene resin with a specific chemical structure is modified with an unsaturated carboxylic acid or its derivative and an ethylenically unsaturated silane compound, carbon black and mica powder are blended, and a free radical generator is added. A resin composition has been proposed (see JP-A-2-269148). This resin composition is said to have excellent processability and impact resistance, and does not cause warping in molded products, but the annealing temperature of injection molded products is 13
The temperature is set at about 5° C. or lower, and the drying temperature before surface mounting is set at about 130° C. or lower, and thermal deformation occurs at 145° C. or higher.

[0007] Therefore, in order to increase the annealing temperature to about 170°C or to shorten the drying time, it is necessary to increase the drying temperature to 1.
It cannot meet the demand for drying treatment at a temperature of about 45 to 155° C. for about 10 hours, and is unsatisfactory in terms of heat resistance.

[0008]

[Problems to be Solved by the Invention] The problems to be solved by the present invention are to have electrical conductivity, excellent heat resistance and impact resistance, and not cause warping of the molded product, and in addition, to The problem is that there was no resin composition that had excellent properties and was suitable as a raw material for IC trays.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention uses mica powder based on nylon 66 resin and surface-treated with a silane coupling agent in an amount of 5 to 40% by weight of the total weight. 5 to 30% by weight of carbon black was contained. This achieves the object of obtaining a resin composition that has excellent impact resistance, does not cause warpage in molded articles, and has particularly excellent heat resistance.

[0010] In addition to the above, the present invention also provides
% by weight of a low molecular weight polyester liquid crystal resin to obtain a resin composition that has excellent processability in addition to the above-mentioned properties;
Another purpose is achieved.

Regarding the synthetic resin to be used as the base material, we mainly investigated polyamide and polyester resins, which are general-purpose crystalline thermoplastic resins, from the viewpoint of processability, especially fluidity, and price. If a small amount of moisture is present during kneading, it tends to be easily hydrolyzed and deteriorated, making it unsuitable for adding carbon black, etc., which has a large amount of attached moisture. On the other hand, polyamide resins do not have these drawbacks and have relatively good thermal stability.
Among them, nylon 66 resin has relatively excellent heat resistance and is suitable as a raw material base material for molded products to which heat is applied, so in the present invention, nylon 66 resin is used as the base material.

Nylon 66 resins include homopolymers, copolymers, α, β, polyolefin polymers modified with unsaturated carboxylic acids or derivatives thereof, polymer blends or polymer alloys with ethylene propylene rubber, modified polyphenyleon oxide, etc. Homopolymers are the most preferred in terms of heat resistance and cost. It should be noted that the molecular weight does not need to be particularly specified, since it has some influence on the quality of processability.

However, the homopolymer of nylon 66 resin has a glass transition point of about 80°C, and also has a high load (1
(8.6 kgf/cm2) The heat deformation temperature is about 66° C., and when used in an IC tray, it cannot be used as it is, so it is necessary to improve the heat resistance with additives.

Generally, when a material with higher strength and stiffness and a higher aspect ratio is added to the resin matrix as a reinforcing material, the strength and stiffness of the composite material will be higher than that of the base resin matrix, and as a result, It is already known that the high-load heat distortion temperature, which is a measure of heat resistance, is also high, but among known reinforcing materials, those with extremely high aspect ratios, such as glass fiber and carbon fiber, This is not preferable because it causes orientation during molding, causing warpage and distortion in the molded product, and poor dimensional accuracy. Aspect ratio is 20-60 like scaly mica powder
Not only can the stiffness and high-load heat distortion temperature be improved to the same level as composite materials with glass fiber added, but the molded product can be corrected without causing warping or distortion. It has favorable properties. Incidentally, inorganic fillers such as wollastonite and talc, which are acicular crystals and have an aspect ratio of about 20, provide the same properties as mica powder in terms of physical properties, but they cause warping and distortion in molded products. .

As described above, mica powder is suitable as a raw material for IC trays and the like that require shape stability of molded products in addition to heat resistance and processability, and therefore mica powder is used in the present invention. The amount added is in the range of 5 to 40% by weight, preferably 15 to 35% by weight, based on the total weight of the resin composition. That is, if the amount is less than 15% by weight, the heat resistance will gradually decrease and warping and distortion will occur easily, and if it is less than 5% by weight, the purpose will not be achieved.
On the other hand, if the amount is more than 35% by weight, the processability and physical properties will deteriorate, and if it exceeds 40% by weight, it cannot be ignored, so it was decided to mix it within the above range.

[0016] Here, in order to eliminate the disadvantage that increasing the amount of mica powder as a reinforcing material to improve heat resistance is accompanied by a decrease in processability and physical properties, the present invention uses γ-amino Propyltrimethoxysilane, N-β-(aminoethyl)γ-aminopropyltrimethoxysilane,
An aminosilane coupling agent such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane is added to 100 parts by weight of mica powder at 0.05 to 5 PHF,
Surface treatment using preferably 0.2 to 2 PHF improves the adhesion and wetting of the interface between the base material nylon 66 resin and the mica powder, improving processability and strength at the weld part of the molded product. I took steps to measure it.

[0017] Methods for silane treatment of mica powder include pretreatment using a water dissolution method, an organic solvent method, and a spray method.
Although there is a method using an integral blending method in which mica powder and a silane coupling agent are mixed with other additives into the base synthetic resin and melt-kneaded, the pretreatment method is more preferable.

Next, as conductive substances added to provide conductivity, carbon black, carbon fiber, metal fiber, metal oxide, inorganic filler for metal surface coating treatment, etc. are known. Carbon black is used in the present invention from the viewpoint of not causing warpage or distortion in the product and from the viewpoint of cost, and the amount of carbon black added is 5 to 30% by weight, preferably 15 to 25% by weight of the total weight of the resin composition. range. In other words, if the amount is less than 15% by weight, the conductivity will gradually decrease, and if it becomes less than 5% by weight, the purpose will not be achieved.On the other hand, if the amount is more than 25% by weight, the amount of other additives used will be reduced. The maximum content was limited to 30% by weight since it would limit or reduce processability.

[0019] As the carbon black, for example, N
2. Porous and large surface area with BET surface area of 240 m2/g or more, small and fine particle size, well-developed structure, highly graphitized, and low in impurities. It is preferable to select and use one.

[0020] Furthermore, it is preferable that the total amount of the above-mentioned mica powder and carbon black be 60% by weight or less of the total weight content of the resin composition. It is possible to prevent the properties of each from being impaired in a combined use system.

As described above, in the present invention, in addition to conductivity, mica powder and carbon black are blended in a fairly large amount in order to prevent warping and distortion of the molded product and to improve heat resistance. Even if mica powder is surface-treated with a chemical agent, processability may inevitably deteriorate.

As a countermeasure against this problem, in the present invention, a low molecular weight polyester liquid crystal resin is added in an amount of 0.5% of the total weight of the resin composition.
It was decided to add it in an amount of ~10% by weight, preferably 1~5% by weight, thereby eliminating the deterioration in processability without adversely affecting other performances.

[0023] The resin composition of the present invention, which essentially contains the above-mentioned substances, is prepared by heating each component at 250 to 350°C, preferably 270 to 300°C, using an ordinary extruder, kneader, Banbury mixer, etc.
It can be obtained by melt-kneading at a temperature of It is common to use It goes without saying that commonly used antioxidants, antistatic agents, ultraviolet absorbers, lubricants, etc. can be appropriately blended into the resin composition of the present invention.

[0024]

[Action] Mica powder surface-treated with a silane coupling agent, carbon black, and a predetermined amount of low molecular weight polyester liquid crystal resin are added to the base material nylon 66 resin, and these are melted and kneaded to form a resin composition such as pellets. get. This resin composition has not only electrical conductivity due to carbon black, but also high heat resistance due to mica powder, and improved strength and dimensional stability due to the silane coupling agent on its surface.
It has high processability due to the silane coupling agent and low molecular weight polyester liquid crystal resin, and its molded products have high strength and have a heat distortion temperature under high load of at least 200°C, making it suitable for high-temperature annealing and IC packages. Withstands high temperature drying.

[0025]

[Examples] Next, the present invention will be explained with reference to Examples and comparative examples. Here, the evaluation methods used in the Examples and Comparative Examples are as follows. ■Evaluation 1: High load thermal deformation temperature (according to JISK7207) A test piece with a length of 130 mm, a width of 13 mm, and a thickness of 6.5 mm was made by injection molding, and the thermal deformation temperature (°C) under a load of 18.6 kgf/cm2 Measure. ■Evaluation 2: Width 5mm using spiral flow long injection molding machine IS80EPN (Toshiba Machine)
, the flow length (cm) is measured when molded in a spiral mold with a thickness of 3 mm under conditions of an injection temperature of 300°C, an injection pressure of 120 kgf/cm2, and a mold temperature of 80°C. ■Evaluation 3: 31 using molded product appearance injection molding machine IS170FIII (Toshiba Machine)
Injection temperature of 5 x 150 x 7 (mm) IC tray (18 IC packages can be mounted) is 300℃, mold temperature is 80℃
The product is molded under these conditions, and its appearance is visually observed to determine whether it is good or bad based on the presence or absence of flow marks and gas burns. ■Evaluation 4: Surface resistance of molded product Using a 4261ALCR meter (Yokogawa Hewlett-Packard), the IC tray molded in Evaluation 3 was measured at three arbitrary locations at 1 cm intervals, and the average value (×10 4 Ω) was determined. ■Evaluation 5: Impact strength evaluation of molded product The IC tray molded in 3 was dropped from a height of 1 m with the short side parallel to the concrete floor surface, and the presence or absence of damage was observed. (2) Evaluation 6: Peeling of the welded portion of the IC tray.A bending force is applied to the welded portion of the IC tray molded in Evaluation 3 with both hands, and the presence or absence of peeling is observed. ■Evaluation 7: Evaluation of warpage of molded product Place the molded IC tray in 3 on a surface plate and measure the warpage (mm) at the center using a gap gauge.

[0026]Evaluations 4, 5, 6, and 7 are all 160
This was performed after annealing at 155° C. for 10 hours and baking at 155° C. for 5 hours.

The substances used in the Examples and Comparative Examples are as follows. ■Resins A: Amiran 3007 (Toray) (low viscosity type nylon 66 homopolymer) B: Amilan 1007 (Toray) (low viscosity type nylon 6 homopolymer) C: Novadur 5010 (Mitsubishi Kasei) (low viscosity type polypropylene) tylene terephthalate homopolymer) D; JSR
-T-7741P (Japan Synthetic Rubber) (4% maleic anhydride modified ethylene/propylene rubber E; Rodrun LC
-300 (Unitika) (Low molecular weight polyester liquid crystal resin) ■F as an inorganic additive; Suzolite Mica 200H
K (Kuraray) (average particle size 90μ, average aspect ratio 5
0 surface treated product) G: Suzolite Mica 200KI (Kuraray) (F surface treated product with aminosilane coupling agent) H: NUC-A-1100 silane (Nippon Unicar) (γ-aminopropyltrimethoxysilane) J ; Carbon black (Mitsubishi Kasei, Conductive Carbon Black 3
250)

[0028] Furthermore, 1.0% by weight of H based on F was added to an aqueous alcohol solution of 5 times the amount of water-alcohol ratio of 1-9, mixed until completely dispersed, and F was uniformly stirred with a Hensel mixer. The mixture was added little by little over several minutes, and after the entire amount was added, the mixture was further stirred for 10 minutes. Next, it was taken out into a shallow tray and dried at 120° C. for 2 hours to produce mica powder whose surface was treated with the silane coupling agent used in Example 3.

The above-mentioned resins and inorganic additives were blended in the proportions shown in Table 1, and a two-shaft kneader (TEX) rotating in the non-interlocking direction was used.
-35, Toshiba Machine) at 270° C. to produce a pellet-shaped resin composition. Using this resin composition, test pieces for evaluation 1, IC trays for evaluation 3 to 7 were molded, and molding for evaluation 2 was performed, and the evaluation results shown in Tables 1 and 2 were obtained. That is, Table 1 shows the composition ratios of Examples and their evaluations, and Table 2 shows the composition ratios and their evaluations of Comparative Examples.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

Effects of the Invention As is clear from the above, the resin composition of the present invention has high heat resistance, strength, and processability in addition to electrical conductivity, and exhibits very small warping and distortion even when heated. It is possible to provide molded products with excellent stability at low cost, especially when molding IC trays.
In addition to IC package drying treatment at temperatures around 170°C,
It has the advantage of being able to withstand moderate molded product annealing treatments and shortening the heat treatment time for manufacturing and handling.

Claims (4)

[Claims] [Claim 1] The base material is nylon 66 resin, and contains mica powder surface-treated with a silane coupling agent in an amount of 5 to 40% by weight of the total weight and carbon black in an amount of 5 to 30% by weight. A heat-resistant and conductive resin composition. [Claim 2] Nylon 66 resin as a base material, mica powder surface-treated with a silane coupling agent of 5 to 40% by weight of the total weight, carbon black of 5 to 30% by weight, and 0.5 to 10% by weight. % of a low molecular weight polyester liquid crystal resin. 3. The heat-resistant and conductive resin composition according to claim 1, wherein the total amount of mica powder and carbon black is 60% by weight or less of the total weight content. 4. The heat-resistant and conductive resin composition according to claim 1, wherein the base material is a homopolymer of nylon 66 resin.