JP3299313B2 - Heat-resistant conductive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a plastic molded product having a dimensional stability of 1 × 10 3
^The present invention relates to a heat-resistant conductive resin composition applied to a field requiring conductivity of less than ⁵ Ω. In particular, the present invention relates to a heat-resistant conductive resin composition which is easily affected by static electricity of a semiconductor integrated circuit, a semiconductor integrated circuit mounting board, or the like, and is most suitable for a jig in a process of an electronic component requiring heat treatment and a molding material of a transfer container.

[0002]

2. Description of the Related Art Conventionally, as a resin composition of the above object,
In most cases, a conductive carbon black was blended with a polypropylene resin composition or a polyphenylene ether resin composition, and the mixture was melt-kneaded into pellets.

[0003] Among them, a polypropylene resin composition is inexpensive by highly filling a polypropylene resin and / or a polypropylene-polyethylene copolymer resin with an inorganic filler such as talc, calcium carbonate, and mica. And the desired conductivity is provided by carbon black. However, recently,
The demand for heat-resistant dimensional accuracy required for molded articles is becoming more sophisticated, and the polypropylene resin compositions that have been used conventionally cannot actually meet the increasing required performance. Specifically, the heat-resistant limit temperature of the compact
At 125 ° C, dimensional changes and warpage become significant under higher temperature conditions. If the dimensional accuracy is more severe,
It is widely recognized that it is not sufficient even for a use environment of 5 ° C.

[Problems to be solved by the invention]

[0004] A tray made of the heat-resistant conductive resin composition obtained by blending carbon black with a modified polyphenylene ether resin has a strict dimensional accuracy even under severe conditions of repeated treatment at a heating temperature of 150 ° C for a long time. We can cope enough.

[Problems to be solved by the invention]

At present, modified polyphenylene ether-based heat-resistant conductive resin compositions have good dimensional stability under high-temperature heating, but must be more expensive than polypropylene-based heat-resistant conductive resin compositions. There is a problem that there is no.

The high cost of a heat-resistant conductive resin composition using a modified polyphenylene ether-based resin is caused by the resin itself having sufficient fluidity when molding the polyphenylene ether-based resin composition and mechanical properties of the molded article. Keep good,
This is because expensive conductive carbon black had to be used in order to impart conductivity. Examples of such conductive properties include Ketjen Black EC (Ketjen Black International),
Vulcan XC-72 (Cabot Corporation) and Denka Black (Denki Kagaku Kogyo Co., Ltd.).

[0007] These conductive brands of carbon black are:
It is extremely expensive and can be four to eight times as expensive as carbon black for rubber kneading at a unit price. Therefore, a heat-resistant conductive resin composition made of an amorphous resin obtained by blending these conductive brands of carbon black is clearly higher in price than a polypropylene-based heat-resistant conductive resin composition, and in terms of performance. However, despite its superiority, there was a problem that market penetration did not expand.

[0008] As a heat-resistant conductive resin, a technical limit in electrical conductivity represented by a modified polyphenylene ether-based resin is that a heat deformation temperature (JIS K-7207) is 120 ° C or higher, and generally, a melt processing temperature during molding is as follows. This is a problem common to amorphous heat-resistant resins that are heated to 260 ° C or higher.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a heating deformation temperature (JIS K-7207) of 12 ° C.
The amount of iodine adsorbed is 52 mg / g to 72 mg / g, and the amount of DBP oil absorbed is 152 ml /
100g-182ml / 100g, 24M4DBP Oil absorption 100m
1/100 g or more, characterized in that it is a heat-resistant conductive resin composition containing 20 to 40 parts by weight of furnace type carbon black having a toluene coloring transmittance of 85% or more.

The amorphous heat-resistant resin which is the object of the present invention has a heat deformation temperature (JIS K-7207) of 120 ° C. or more and a molding temperature of a commonly used molding machine of 260 ° C. or more. It is a polycarbonate resin, a modified polyphenylene ether resin, a polysulfone resin, a polyethersulfone resin, and the like, and can be easily obtained in Japan and overseas. The amorphous heat-resistant resin is generally supplied in the form of pellets, but may be supplied in the form of beads, flakes, or powder. The shape of the resin may be selected according to the purpose of processing.

The carbon black used in the present invention is a carbon black for kneading rubber, which is mainly made of inexpensive coal pitch or petroleum residue among furnace blacks. The conductive mechanism of carbon black is described by the transfer of pi (π) electrons. Carbon black, to which π electrons easily move, has high conductivity, but carbon black for rubber kneading generally has low purity of raw material oil (carbon , Containing many elements other than hydrogen), the carbon black obtained through the furnace has a high content of oxygen, sulfur, and nitrogen that hinder the transfer of pi (π) electrons.

Furthermore, carbon black for rubber kneading has not been expected as a conductive carbon black in the past because crystals of carbon black particles hardly develop for the same reason. However, the present inventors have invented a method of obtaining an effect equivalent to that of an expensive conductive carbon black by using an inexpensive carbon rubber for kneading rubber through a long-term research on conductivity of a modified polyphenylene ether-based resin.

That is, the characteristics of the carbon black used in the present invention are that the amount of adsorbed iodine is 52 mg / g to 72 mg / g,
P Furnace-type carbon black having an oil absorption of 152 ml / 100 g to 182 ml / 100 g, a 24M4DBP oil absorption of 100 ml / 100 g or more, and a toluene coloring transmittance of 85% or more. It is characterized by.

The carbon black specified above can be mass-produced by using an inexpensive raw material oil and controlling the furnace furnace under certain conditions, and is expensive as in the case of conventional conductive carbon black. And no source gas is required, so that it can be obtained inexpensively and in large quantities.

Further, the heat-resistant conductive resin composition of the present invention comprises:
If necessary, reinforcing resins and rubbers, inorganic fillers such as glass fiber, calcium carbonate, talc and mica, and additives such as antioxidants, plasticizers, surfactants and lubricants may be used.

The heat-resistant conductive resin composition of the present invention is obtained by uniformly mixing the raw materials using a commonly used mixer such as a Henschel mixer, a ribbon blender and a tumbler mixer. Subsequently, the mixture is melt-kneaded at a temperature of 260 ° C. or higher using a widely-used kneading / extruder such as a pressure kneader, a Banbury mixer, a single screw extruder, and a twin screw extruder to form pellets. It is a resin composition.

[0017]

Next, the present invention will be described based on embodiments. Example 1 and Comparative Example 1 Table 1 shows that the furnace type carbon blacks (A) and (B) used in the present invention as Example 1 and other carbon blacks (C), (D) and ( With respect to E) and (F), characteristic values serving as indices of conductivity were shown.

Carbon blacks (A) and (B) are carbon blacks within the scope of the present invention. Considering (A), (B) shows that DBP oil absorption and 24M4 are within the scope of the invention.
The DBP oil absorption is further improved. On the other hand, Comparative Example 1
(C) is inferior to (A) in all the characteristic values shown in Table 1, and (D) is characterized by adjusting the iodine adsorption amount relatively large. Are carbon blacks outside the scope of the present invention.
In addition, the conductive brand carbon blacks (E) and (F) listed as Comparative Example 1 have both a large amount of iodine adsorption and a large amount of DBP oil absorption, and both are expected to have high conductivity. It is extremely expensive compared to the furnace type carbon black of the invention.

[0019]

[Table 1]

Example 2 and Comparative Examples 2-3 In Tables 2 and 3 of the present invention, various carbon blacks, modified polyphenylene ether resins and high-impact polystyrene polymers listed in Table 1 are represented by the following proportions: First, a modified polyphenylene ether-based resin and a high impact polystyrene polymer (beads) were mixed for 2 minutes by a mixer having high-speed rotating blades. Subsequently, the mixture and carbon black were mixed for about 3 minutes using a tumbler mixer. The mixture was then supplied to a co-rotating twin-screw extruder, and in order to suppress heat generation due to mechanical shearing as much as possible, a temperature gradient was applied to the cylinder in the range of 260 ° C to 300 ° C, and the mixture was melt-kneaded and extruded into pellets. . As test pieces used for evaluation of physical properties, each sample piece was prepared by an injection molding method using the obtained conductive heat-resistant resin composition. The results are shown in Tables 2 and 3. The modified polyphenylene ether-based resin used was composed of 85% by weight of a 2,6-dimethylpolyphenylene ether polymer and 15% by weight of a high impact polystyrene polymer, and had a composition having relatively high heat resistance and high viscosity. The amount of carbon black is (A), (B), (C) per 100 parts by weight of the resin.
And (D) were each 33 parts by weight, and in (E) and (F), consideration was given to 25 parts by weight with respect to 100 parts by weight of the resin so as to obtain desired conductivity and physical properties.

Carbon black (A) or (B)
With the resin composition used in 33 parts by weight, the desired conductivity (less than 1 × 10 ⁵ Ω in surface resistance value) was obtained, and good results were obtained in other physical property balances.

In the resin composition using 33 parts by weight of carbon black (C), the desired conductivity (1 in surface resistance value)
× 10 ⁵ Ω) was not obtained. Although the conductivity is improved by increasing the mixing ratio of carbon black (C) to the resin, the viscosity of the resin composition is increased and the impact strength is remarkably reduced, so that it is difficult to obtain a good molded product. .

In the resin composition using 33 parts by weight of carbon black (D), the desired conductivity (1 in terms of surface resistance value) was obtained.
× 10 ⁵ Ω), but the melt flow rate was 30
It is expected that the melt viscosity will increase significantly as observed at 0.1 ° C or less at 0 ° C and a load of 5 kg at a load of 5 kg or less, and it is expected that the fluidity will be impaired when subjected to injection moldability, etc. It becomes difficult. Further, in the resin composition using carbon black (D), deterioration of the resin is promoted at the stage of melt processing as observed in a decrease in Izod impact strength.

[0024]

[Table 2]

When conductive brand carbon black (E) or (F) was used, sufficient conductivity and good balance of physical properties were obtained with a lower blending ratio (25 parts by weight). High prices have resulted in soaring raw material prices as compositions. The raw material price changes depending on the composition ratio, and when the price of carbon black is lower than the resin price, the price is lowered by increasing the mixing ratio of carbon black. For example, in the case of (E), 66 parts by weight and in the case of (F), 78 parts by weight are almost the same price as the resin composition using 33 parts by weight of (A).

However, the carbon black of the conductive brands has a remarkable increase in the melt viscosity of the composition with an increase in the blending ratio, resulting in a remarkable decrease in fluidity and impact strength. There is. When carbon black (E) or (F) is blended with a polyphenylene ether-based resin, the upper limit is considered to be 35 parts by weight based on experience so far.

As is apparent from Example 2 and Comparative Examples 2 and 3, 33 parts by weight of the carbon blacks (A) and (B) are blended with the modified polyphenylene ether-based resin to obtain a conductive brand. It has been found that the same conductivity and physical properties as in the case of using the carbon black (E) or (F) can be obtained, and a heat-resistant conductive resin composition at lower cost can be obtained.

[0028]

[Table 3]

Examples 3-4 and Comparative Examples 4-5 The same operation as in Example 1 was carried out except that the mixing ratio of the modified polyphenylene ether-based resin and carbon black (A) was set to the ratio shown in Table 4. . Table 4 shows the physical property values.

[0030] When the compounding ratio of carbon black (A) is 22 parts by weight or 38 parts by weight conductive to the target (1 × less than 10 ⁵ Omega in surface resistance) is obtained, and the fluidity for practical use The impact strength was secured.

On the other hand, when the compounding ratio of (A) was 18 parts by weight, the desired conductivity (less than 1 × 10 ⁵ Ω in surface resistance) could not be obtained. On the other hand, when the compounding ratio of (A) is 42 parts by weight, the target conductivity (1 × 10 ⁵ Ω in surface resistance value) is obtained.
) Was obtained, but resulted in a marked decrease in flowability and Izod impact strength. In the case of the modified polyphenylene ether resin, the fluidity required for injection molding is 300 ° C, 5
The melt flow rate at a load of kg is 0.3 g / 10 min or more, and 3 kg-cm / cm of Izod impact strength (1/16 inch, with notch) is required to give sufficient strength to the molded product.

As described above, from Examples 3 and 4 and Comparative Examples 4 and 5,
The compounding ratio of carbon black (A) required to effectively make the modified polyphenylene ether-based resin conductive is as follows.
It proved to be in the range of 20-40 parts by weight for 100 parts by weight.

[0033]

[Table 4]

Embodiment 5 The effect of the present invention is not limited to the modified polyphenylene ether-based resin, but is generally a polycarbonate resin (hereinafter referred to as PC), a polysulfone resin (hereinafter referred to as PSu), a polyether sulfone having a melt processing temperature of 260 ° C. or higher. Resin (hereinafter P
(Referred to as ES). Table 5
Shows an example in which 33 parts by weight of carbon black (A) is used with respect to 100 parts by weight of the amorphous heat-resistant resin. The method of mixing and kneading the resin composition was the same as in Example 1.

In each case, the target conductivity (1 × in surface resistance value)
(Less than 10 ⁵ Ω) and good physical properties are obtained.

[0036]

[Table 5]

The method of measuring the physical resistance between two points is as follows. Test piece: flat plate (120mm x 120mm x
3 mm). Pretreatment: For the purpose of minimizing the variation in the contact resistance of the measurement terminal and the measured value, a silver paint was applied to the flat plate to form an electrode of the test object. The silver electrode had an area of 5 mm × 10 mm, and the interval between a pair (two sides) was 10 mm. Measurement method: Measured by a four-terminal method (Advantest Digital Multimeter TR6871).

[0038]

As described above, according to the present invention, an amorphous heat-resistant resin can be efficiently produced using a furnace type carbon black having specified iodine adsorption amount, DBP oil absorption amount, 24M4DBP oil absorption amount and toluene coloring transmittance. By conducting well, it is possible to supply a heat-resistant conductive resin composition having excellent dimensional stability under high-temperature heating to the market at a lower price. Further, the heat-resistant conductive resin composition of the present invention,
In particular, it is most suitable for a jig in a process of an electronic component and a molding material for a transport container, which are easily affected by static electricity of a semiconductor integrated circuit or a semiconductor integrated circuit mounting board and require heat treatment, and a transport container.

Claims (1)

(57) [Claims] 1. An iodine adsorption amount of 52 mg / g to 72 mg / g and a DBP oil absorption amount of 152 ml / 100 parts by weight of an amorphous heat-resistant resin having a heat distortion temperature (JIS K-7207) of 120 ° C. or higher. 100
g ~ 182ml / 100g, and 24M4DBP oil absorption 100ml /
A heat-resistant conductive resin composition comprising 100 g or more and 20 to 40 parts by weight of a furnace type carbon black having a toluene coloring transmittance of 85% or more.