JPH0689190B2 - Conductive resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has conductivity, exhibits extremely low shrinkage and its isotropy, and is highly balanced in rigidity, impact resistance and heat resistance.
The present invention relates to a conductive resin composition which is small in warp deformation and dimensional change even in high heat treatment after injection molding and has excellent heat resistance.

[0002]

2. Description of the Related Art Conventionally, the following methods (1) to (4) are known as techniques for producing a heat-resistant conductive resin by blending a conductive resin with a conductive carbon black and mica. JP-A-58-206646, (a) Crystalline propylene having an extractable content of 23 ° C. xylene of 10 to 50% by weight and a propylene content of the extractable content of 30% by weight or more. A conductive resin composition containing 20 to 90% by weight of a polymer resin, (b) 75 to 10% by weight of mica having an average particle size of 200 μm or less, and (c) 2 to 50 parts by weight of carbon black.

JP-A-2-138366, (a) 10 to 60% by weight of a thermoplastic resin having a melting point of 150 ° C. or more and a heat distortion temperature of 95 ° C. or more, (b) an inorganic filler having a plate-like particle shape 10 A conductive resin composition comprising 45% by weight, (c) inorganic fibers 3 to 20% by weight (d) conductive filler 3 to 30% by weight, and (e) thermoplastic elastomer 3 to 25% by weight.

JP-A-2-269148, A (a) 70 to 95% by weight of a propylene homopolymer and 30 to 5% by weight of an ethylene / propylene copolymer, a propylene / ethylene block copolymer (having an ethylene content of 3 Modified polypropylene with unsaturated carboxylic acid and ethylenically unsaturated silane compound 67 to 35% by weight (b) carbon black 3 to 15% by weight (c) mica powder 30 to 50% by weight Melt-kneading resin composition of 100 parts by weight B Free radical generator 0.01-0.1 parts by weight of a conductive compound for heat-resistant IC pallet, which is melt-kneaded.

[0005]

However, these conductive resin compositions are used when they are used as a molded body material such as an IC component storage container used for dehumidifying a sealing resin. Is subjected to heat treatment at a temperature of 125 to 135 ° C. for about 24 hours together with the IC (integrated circuit), so that heat resistance against high temperature and dimensional change, warpage or deformation due to such heat should not occur. Since strict performance such as not being required is required, it is the actual situation that the performance that satisfies these requirements cannot be obtained yet. In addition, since these compositions contain a plate-like filler such as mica (mica) in a high concentration in order to impart heat resistance, the composition has poor fluidity and insufficient weld strength. In addition, in order to improve the weld strength, a part of these mica is replaced with a fibrous filler, because the balance of the fluidity of the resin and the heat shrinkage in the direction perpendicular to the flow is extremely deteriorated. It may cause warping or deformation. Furthermore, when various modified resins are used as materials for these conductive resin compositions, physical properties are considered to be decreased due to the presence of unreacted substances under the condition of heat treatment at a temperature of 125 to 135 ° C. for 24 hours. Also in this respect, there is a problem in thermal stability.

[0006]

Means for Solving the Problems [Summary of the Invention] As a result of intensive studies conducted by the present inventors in view of the above problems, a specific composition comprising a crystalline propylene polymer, mica, a spherical filler and carbon black was obtained. The resin composition of (1) has a significantly improved heat shrinkage balance caused by heat treatment at a high temperature for a long time, has extremely small warpage and deformation, and has sufficient weld strength and sufficient mechanical strength even after heat treatment. The present invention has been completed based on the finding that an injection molded body can be obtained.

That is, the conductive resin composition of the present invention is
It consists of (a) to (d) components shown below, and the proportion of each component is such that (a) component is 40 to 75% by weight based on (a) + (b) + (c), and (b) component is 20-40% by weight based on (a) + (b) + (c), 5-20% by weight of component (c) based on (a) + (b) + (c), and component (d) Is 5 to 30 parts by weight based on 100 parts by weight of (a) + (b) + (c), which is a conductive resin composition. (a) Component: crystalline propylene having 23 to 15 ° C xylene extractable content of 3 to 15% by weight, propylene content of the extractable content of 40% by weight or more, and MFR of 15 to 60 g / 10 min. Polymer resin (b) component: Average particle size by light transmission method of liquid phase sedimentation method is 1
Mica (c) component of 20 μm or less: ratio of major axis to minor axis (sphericity) of 1.5 or less,
Spherical particle filler having an average particle diameter of 5 to 50 μm (d) Component: at least one carbon black selected from super conductive furnace, extra conductive furnace and acetylene black

[Detailed Description of the Invention] [I] Conductive Resin Composition (1) Constituent Component (a) Crystalline Propylene Polymer Resin Component [(a) Component] (a) of the conductive resin composition of the present invention The crystalline propylene polymer resin used as the component is a crystalline propylene polymer resin produced by using a Ziegler-Natta type catalyst, and the soluble content of xylene at 23 ° C. is 3 to 15% by weight, preferably 4%. -10 wt% and the propylene content in the extractable solubles is 40 wt% or more, preferably 60 wt% or more, and the MFR (melt flow rate) is 15 to 60 g /
It is 10 minutes, preferably 30 to 50 g / 10 minutes. The crystalline propylene polymer resin is composed of propylene as a main component and other α-olefins having 2 to 12 carbon atoms as a subordinate component.
A crystalline copolymer, which is a copolymerization product with, is suitable for use as the component (a) of the conductive resin composition. Specifically, crystalline propylene / ethylene block or random copolymer, crystalline propylene / butene block or random copolymer, crystalline propylene / hexene block or random copolymer, crystalline propylene / heptene block or random Examples thereof include a copolymer and a crystalline propylene / butene copolymer. Among these, a crystalline propylene / ethylene block copolymer having an ethylene content of 10% by weight or less is preferably used. Such propylene polymer resin can be appropriately selected and used from commercially available products. Those having a 23 ° C xylene extractable content exceeding the above range or having a 23 ° C xylene extractable content within the above range but having a propylene content in the extractable content below the above range have heat resistance. Shows a significant decrease. When the 23 ° C xylene extractable content is less than the above range, the shrinkage rate is poor. Further, if the MFR value is smaller than the above range, the fluidity is significantly reduced, and warpage or deformation is likely to occur, and if it exceeds the above range, the impact strength is reduced, and therefore should be avoided. The 23 ° C. xylene extractable content was measured by placing 3 g of the measurement sample in 1,000 ml of boiling xylene and performing extraction for 6 hours.
It is allowed to cool to 23 ° C. and filtered, and the soluble matter is separated and its weight is measured. In addition, the propylene content in this extractable content is measured by evaporating and removing xylene from the filtrate, forming the obtained extract into a thin film, and measuring it with an infrared spectrophotometer. Can be done by doing.

(B) Mica Component [(b) Component] The mica (mica) used as the component (b) of the conductive resin composition of the present invention has an average particle diameter by the light transmission method of liquid layer sedimentation method. It is 120 μm or less. The use of mica having an excessively large average particle size is not preferable because the impact strength is lowered. Particularly preferred mica has an average particle size of 100 μm or less and has a specific surface area of 3,0.
It is more than 00 cm ² . Measurement of the average particle size (particle size distribution) of mica by the light transmission method of the liquid layer sedimentation method,
It can be determined by measurement using a laser scattered light type particle size distribution analyzer by liquid layer sedimentation. Examples of the measuring device include "LA-500 type" manufactured by Horiba Ltd. In addition, the measurement of the specific surface area is based on an air permeation method and is a constant pressure type ventilation type specific surface area measuring device “SS-1” manufactured by Shimadzu Corporation.
It can be determined by measuring "00". Examples of such mica (white mica) include white mica series mica, that is, white mica, red mica, soda mica, silk mica, vanadium mica, illite, and black mica series mica, that is, black mica, gold mica, chinkled Mica etc. can be mentioned. Among these, white mica, for example, the structural formula is K ₂ Al ₄ (Si ₃ Al)
₂ O ₂₀ (OH) ₄ or gold mica, such as K ₂ Mg ₆ (Si ₃ Al) ₂ O ₂₀ (OH) ₄ , or K
₂ Mg _4.3 Fe _1.2 Al _0.4 [Al _2.3 Si _5.8 O ₂₀ ]
Those represented by (OH) ₄ F ₂ are preferred. The mica used in the present invention may be used without surface treatment, but those treated with various surface treatment agents can be used. As the surface treatment agent, waxes such as low molecular weight polyethylene and low molecular weight polypropylene, saturated higher fatty acids such as stearic acid and palmitic acid, saturated higher fatty acid metal salts such as magnesium stearate, unsaturated higher fatty acids such as oleic acid, Unsaturated higher fatty acid metal salts such as magnesium oleate, titanate coupling agents such as isopropyltriisostearic titanate, silane coupling agents such as γ-aminopropyltriethoxysilane and sulfonylazidosilane, polyoxyethylene alkyl ethers, etc. Various surfactants and the like can be used.

(C) Spherical particle filler component [(c) component] The spherical particle filler used in the component (c) of the conductive resin composition of the present invention is selected from metal, organic and non-metal inorganic materials. The value represented by sphericity (longest diameter / shortest diameter) is 1.5 or less, preferably 1.3 or less, and the average particle diameter is 5
It is a spherical filler having a particle size of ˜50 μm, preferably 10 to 40 μm. If the sphericity exceeds the above range, the fluidity of the resin decreases. Further, if the average particle size is too small, the effect of improving the fluidity cannot be obtained, and if it exceeds the range, the impact strength is lowered.
Examples of such spherical particle fillers include nickel, aluminum and copper for metallic materials, ceramics, glass and calcium carbonate for non-metallic inorganic materials, and 80 ° C. above the melting temperature of crystalline propylene polymer resin for organic materials.
Above, preferably selected from materials showing a melting temperature higher than 100 ° C. or infusible materials. Specific examples of these materials are polyphenylene ether, polyamide, and poly-1,4.
-Cyclohexane dimethylene terephthalate, liquid crystal polymer, polyphenylene sulfide, polyarylate,
Examples thereof include polysulfone, polyether sulfone, polyetherimide, polyketone, polyimide, polyamideimide, polytetrafluoroethylene, and crosslinked polysiloxane. These spherical particle fillers may be used without surface treatment, but surface treatment with a titanate coupling agent such as isopropyltriisostearic titanate or a silane coupling agent such as γ-aminopropyltriethoxysilane or sulfonylazidosilane is performed. A processed product can also be used.

(D) Carbon black component [(d) component] The carbon black used as the component (d) of the conductive resin composition of the present invention has an amorphous structure usually used as a compounding agent for coloring or filling. In contrast to carbon black, which is extremely inferior in conductivity, it is a conductive carbon black whose surface layer has a graphite structure and has a large specific surface area, specifically 50 m ² / g or more, preferably 70 m ² / g or more superconducting Furnace (S.C.F .:
Super Conductive Furnaces), Extra Conductive Furnaces (XCF: Extra Conductive Furnaces)
ce) or at least one carbon black selected from acetylene black. These can be appropriately selected and used from commercially available products. For example, S. C. F
For example, "Vulcan SC" and "Vulcan P" manufactured by Cabot Co., Ltd. C. Examples of F include "Ketjen Black EC" manufactured by Mitsubishi Petrochemical Co., Ltd., "Vulcan XC-72" and "CSX-99" manufactured by Cabot, and "Denka Black" manufactured by Denki Kagaku as acetylene black. Can be mentioned. Two or more of these carbon blacks can be used in combination.

(E) Additional component (optional component) In the conductive resin composition of the present invention, the above (a) to (d)
Although the constituent components of the components are contained as essential components, any additional components can be contained in addition to the above-mentioned essential components within a range that does not significantly impair the effects of the present invention.
As the additional component to be added to the conductive resin composition of the present invention, phenol-based, sulfur-based, phosphorus-based antioxidants,
Examples thereof include metal salts of higher fatty acids, copper damage inhibitors, flame retardants, neutralizing agents, and the like, and these are previously contained in the crystalline propylene polymer resin that is the component (a) of the conductive resin composition of the present invention. It can also be mixed.

(2) Amount ratio In the conductive resin composition of the present invention, the above (a) to (d)
The components are contained as constituents, and the content of each of the constituents is 40 to 75% by weight, preferably 50 to 50% by weight, based on (a) + (b) + (c). 70% by weight,
The component (b) is 20 to 40% by weight, preferably 20 to 30% by weight on the same basis, and the component (c) is 5 to 20% by weight, preferably 10 to 20% by weight on the same basis, and (d) )
(a) + (b) + (c) It is mixed in an amount of 5 to 30 parts by weight, preferably 10 to 20 parts by weight, relative to 100 parts by weight. If the amount of mica as the component (b) in the conductive resin composition is too small than the above range, a sufficient reinforcing effect cannot be obtained, and therefore sufficient heat resistance, rigidity and dimensional accuracy cannot be imparted. . On the other hand, if the amount of the component (b) exceeds the above range, the melt fluidity is significantly reduced, which is not preferable. The decrease in the melt fluidity leads to a decrease in the weld strength, which results in a marked decrease in the impact strength, and further tends to cause residual stress during molding, which causes warpage and deformation during heat treatment. In addition, in the conductive resin composition
If the amount of the spherical particle filler as the component (c) is less than the above range, the sufficient addition effect cannot be obtained. On the other hand, when the amount of the component (c) exceeds the above range, the impact resistance of the molded product is significantly reduced. Further, if the amount of the component (d) carbon black in the conductive resin composition is less than the above range, the conductivity becomes poor and the antistatic function cannot be imparted. On the other hand, when the amount of the component (d) exceeds the above range, the developed structure and the large specific surface area significantly reduce the fluidity, which causes warpage and deformation and lowers the impact strength. Cause.

[II] Production of Conductive Resin Composition (1) Composition The conductive resin composition of the present invention comprises the essential constituents of the above-mentioned components (a) to (d) and optionally (e) The compounding is performed by mixing the components in the ratio of the above amounts. (2) Kneading By melt-kneading the above-mentioned compound, it is mixed in a uniformly dispersed state. In the melt-kneading, various known kneaders such as a single-screw extruder, a twin-screw extruder and a Banbury mixer can be used for uniform mixing.

[III] Application The conductive resin composition of the present invention thus obtained is
When the composition is injection-molded, it is possible to obtain a product having significantly improved warpage, deformation and thermal stability, which are major drawbacks of conventional conductive materials, and have heat resistance, rigidity, impact strength and size. It is possible to obtain a molded product in which accuracy is highly balanced.

[0016]

EXAMPLES The conductive resin composition of the present invention will be specifically described below with reference to the examples. [I] Evaluation Method The evaluations in the examples and comparative examples shown below were performed according to the evaluation measuring method shown below. (1) Evaluation of tray warp The toilet was placed on a surface plate and the maximum warp was measured with a gap gauge. The evaluation was performed according to the criteria shown in Table 1 below.

[0017]

[Table 1]

(2) Shrinkability [Heat shrinkage ratio and shrinkage ratio (isotropic)] The dimensions of the toilet before and after heat treatment at 135 ° C. for 24 hours are measured, and the rate of change in the dimensions is heat shrinked. And rate.
Further, a value indicating the isotropy of shrinkage was obtained by the ratio of the shrinkage ratios in the longitudinal direction and the transverse direction. The shrinkage was evaluated according to the criteria shown in Table 2 below.

[0019]

[Table 2]

(3) Impact resistance strength From a height of 1 m, it was dropped so that the falling point was at the corner of the tray, and the presence or absence of damage was evaluated. No damage ・ ・ ・ ○ Damaged ・ ・ ・ × (4) Conductivity The tray surface specific resistance value was measured using Mitsubishi Yuka's Lorester AP. (5) Heat distortion temperature It was measured according to JIS K-7207 (4.6 kg / cm ² ). (6) Measured in accordance with MFR JIS K-7210.

[II] Examples 1 and 2 and Comparative Examples 1 to 5 (1) Production of Compositions (a) Components (a) -1 to (a) shown in Table 3 were polymerized using a Ziegler-Natta catalyst. (a) -4 propylene / ethylene block copolymer powder, (b) component, gold mica represented by a structural formula K ₂ Mg ₆ (Si ₃ Al) ₂ O ₂₀ having an average particle size of 90 μm, and (c) component As the sphericity (maximum major axis / minimum minor axis) = 1.0, glass beads having an average particle diameter of 20 μm, and glass fiber (fiber diameter 13 μm, length 6 mm) as a comparative fibrous filler (both beads and fibers are aminosilane The surface-treated product was used), and as component (d), Ketjen Black EC (specific surface area 800 m ² / g, particle diameter 30 μm) was blended in the ratio shown in Table 2, and as component (e), oxidation Inhibitor: 0.2 part of 2,6-t-butyl-4-methylphenol Were blended using a PCM twin-screw extruder manufactured by Ikegai Tekko Co., Ltd. at a cylinder temperature of 220 ° C. (setting) and a screw rotation speed of 230 rpm, and the composition extruded from the strand die was pelletized. And a granular composition was obtained.

[0022]

[Table 3]

(2) Molding of molded article for evaluation Using the injection molding machine manufactured by Nippon Steel Co., Ltd., the above granular composition was subjected to 320 × under conditions of a cylinder temperature of 220 ° C. and a mold temperature of 40 ° C. A 140 mm (thickness 2 mm) IC tray (flat plate shape) was injection molded. Using the resulting IC tray, after annealing at 135 ° C for 2 hours, then 135 ° C
Heat treatment was carried out for 24 hours in the constant temperature bath. (3) Evaluation The above-mentioned molded product was evaluated by the above-mentioned evaluation method. The evaluation results are shown in Table 4.

[0024]

[Table 4]

Examples 3 to 6 and Comparative Examples 6 to 10 The propylene / ethylene block copolymer (a) -1 used in Example 1 was used as a base resin, and the particle size of mica and glass beads and the blending ratio were used. Example 1
A granular composition was produced by the same method as described above, and a molded article for evaluation was molded and evaluated. Table 5 shows the obtained evaluation results.
Shown in. In addition, as the component (d) of Example 6, Vulcan X was used.
C-72 (specific surface area 200 m ² / g, particle size 30 μm)
Vulcan P (specific surface area 125 m ² / g, particle diameter 23 μm) was used as the component (d) of Example 7, and Denka black (specific surface area 70 m ² was used as the component (d) of Example 8).
/ G, particle size 50 μm) were used respectively.

[0026]

[Table 5]

[0027]

The electrically conductive resin composition of the present invention, when injection-molded, has significant warpage, deformation and thermal stability, which are major drawbacks of conventional electrically conductive materials. It is possible to obtain a molded product which has improved heat resistance, rigidity, impact strength, and dimensional accuracy.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08K 3:04 3:34 7:16)

Claims (1)

[Claims] 1. It comprises the following components (a) to (d), and the ratio of each component is 4 based on (a) + (b) + (c) of the component (a).
0 to 75% by weight, (b) component based on (a) + (b) + (c) 20 to 40% by weight, (c) component based on (a) + (b) + (c) 5 to 20% by weight, and (d) component is (a) + (b) + (c) 100
The conductive resin composition is 5 to 30 parts by weight with respect to parts by weight. (a) Component: crystalline propylene having 23 to 15 ° C xylene extractable content of 3 to 15% by weight, propylene content of the extractable content of 40% by weight or more, and MFR of 15 to 60 g / 10 min. Polymer resin (b) component: Average particle size by light transmission method of liquid phase sedimentation method is 1
Mica (c) component of 20 μm or less: ratio of major axis to minor axis (sphericity) of 1.5 or less,
Spherical particle filler having an average particle diameter of 5 to 50 μm (d) Component: at least one carbon black selected from super conductive furnace, extra conductive furnace and acetylene black