JP2676242B2 - White conductive resin composition with improved whiteness and light resistance - Google Patents

Description

TECHNICAL FIELD The present invention relates to a white conductive resin composition having improved whiteness and light resistance, and the conductive resin composition can be colored freely and is stable. Since it maintains a resistance value, it is used in various applications such as antistatic paints, antistatic flooring materials, electromagnetic wave shielding materials, or materials for electrostatic recording, which require whiteness, coloring and conductivity.

[Conventional technology and its problems]

Various materials such as antistatic coating materials, antistatic floor materials, electromagnetic wave shielding materials, and materials for electrostatic recording, which are made to have electrical conductivity with a resin, have already been put into practical use. Two representative methods for imparting conductivity to these resins are known: a method of kneading a surfactant or an ionic polymer or surface coating, and a method of kneading a conductive filler. However, the method of kneading a surfactant has the advantage that it can impart conductivity to the resin without coloring, but its conductivity is limited to a surface resistance of about 10 ⁸ Ω / □ and changes in humidity. It cannot be used in applications where high conductivity or stable conductivity for a long period of time is required due to the drawback that the resistance value fluctuates due to abrasion or friction. On the other hand, when a conductive filler, such as metal powder or carbon black, is added to give conductivity to the resin, the conductivity can be arbitrarily adjusted within a fairly wide range from 10 ² to 10 ¹⁰ Ω / □ by adjusting the filling amount. Although it can be prepared, there is a problem that a white material cannot be obtained because the resin is darkened or colored with a metal color, and it is not possible to prepare a desired color tone.

Therefore, various inventions have been devised as methods for solving these problems. For example, fibrous potassium titanate covered with tin oxide described in JP-A-59-6235 and JP-A-61-
The invention is known that a stable conductive resin having a high whiteness can be obtained by using the potassium titanate fiber coated with tin oxide and antimony oxide described in 136532.
However, according to a study by the present inventors,
In the case of a resin containing these fillers, the conductivity and resistance stability are excellent, and since the fibrous filler brings about the reinforcing effect of the resin, although the strength is also excellent, the whiteness is It has been found that the problem is not sufficient yet, and further, when the light is received, the tin oxide coating layer is reduced and becomes dark over time.

[Problems to be solved by the invention]

An object of the present invention is to use a conductive filler having improved whiteness and light resistance, to maintain stable conductivity, and to freely paint. It is to provide a conductive resin composition having excellent whiteness and light resistance.

[Means for solving the problem]

The inventors of the present invention have conducted extensive studies to provide a conductive resin composition having improved whiteness and light resistance, and as a result, are covered with a tin oxide or antimony oxide-based conductive coating that has been conventionally used. It has been found that a resin composition in which the above-mentioned drawbacks are significantly improved can be obtained by using a conductive filler covered with conductive exposure of tin oxide, antimony oxide, or cobalt oxide instead of the conductive filler. Was completed.

The configuration of the present invention will be specifically described below. The conductive filler in the white conductive resin composition of the present invention has a white or pale colored fibrous or scaly inorganic material as a core material, and the surface thereof is covered with a composite oxide film composed of tin oxide, antimony oxide and cobalt oxide. The broken one is used. Here, since properties such as conductivity, whiteness, and light resistance of the filler are mainly defined by the composition of the surface-coated complex oxide, the following compositions are used. That is, in order to obtain the white conductive resin composition of the present invention, the composition of the composite oxide coating on the surface of the conductive filler is 90 to 85 tin.
It is essential that the content is 10% by weight, 10-15% by weight antimony, and 0.05-1% by weight cobalt. In the composition of the composite oxide film, when the proportion of tin oxide exceeds 90% by weight, the whiteness becomes higher, but the conductivity cannot be exhibited. On the contrary, when the proportion of tin oxide is 85% by weight or less, the complex oxide coating turns from gray to black, and the object of the present invention cannot be obtained. In the conductive filler used in the present invention, a light amount of cobalt oxide is newly added to the coating film of tin oxide / antimony oxide-based composite oxide, which is a conductive material having a large ΔE, which is conventionally poor in light resistance. It is possible to improve whiteness and light resistance. The addition of cobalt oxide produced the result in a very small amount, and was about 0.05 to 1 based on the total weight of tin / antimony in the composite oxide film.
Addition of wt% is sufficient.

As the shape of the white or light-colored base material coated with the above-mentioned complex oxide, in the case of a fibrous filler,
The acicular ratio is 10 to 10000 and the major axis length is 0.1 μm to 5 mm, and in the case of scale-like filler, the flake diameter is 10 μm
It is preferable that the thickness is -5 mm and the thickness is 0.05 μm-10 μm.

Specific examples of these base materials are as follows. Scale-shaped or plate-shaped substrate is also called flake-shaped substrate,
Mica is common. Taking natural mica as an example, mica is a silicate-based aluminum silicate-based mineral, and there are many types depending on the difference in the ingredients.
Of these, muscovite is preferred. In addition, there can be mentioned sericite, talc and the like. Examples of artificial materials include mica coated with titanium oxide and glass flakes and alumina flakes.

The needle-shaped substrate includes natural products and artificial products, and asbestos and wollastonite are typical natural products. Asbestos has a long history as a needle-shaped base material and has excellent reinforcing properties, but as a causative agent of asbestosis and cancer, asbestos has been prohibited in other countries. Wollastonite is often used in anhydrous calcium silicate.
Artificial materials include potassium titanate fiber, gypsum fiber, xonotlite, MOS fiber, (MgSO ⁴ / 5MgO / 8H ₂ O) PMF (Pro
cessed Minral Fiber) Glass fiber, alumina fiber, ceramic fiber, rock wool fiber, etc. can be mentioned.

In addition to the above-mentioned base material, if it is a fibrous or scaly white color, it can be used as the base material of the present invention.
Substrates that decompose, melt or deteriorate in the temperature range of 00 ° C are not preferred.

The white conductive filler used in the present invention is a composite hydroxide of tin / antimony / cobalt which is obtained by reacting the above-mentioned base material with tin chloride and an antimony-based compound and a cobalt-based compound in an alkaline aqueous solution. Form a film, and then age it in an acidic solution, dehydrate and dry it, and then
It is heated to a high temperature of 0 ° C to 800 ° C to complete the complex oxide film. At this time, if the ratio of tin in the composite oxide film is higher than the above range, the whiteness is improved but the conductivity cannot be exhibited. On the contrary, when the ratio of antimony increases, the color tone of the filler changes from gray to black and the whiteness decreases.

The binder resin to be filled with the filler obtained by the above method, polyethylene, polypropylene,
Suitable selection from any resin such as polystyrene, vinyl acetate, vinyl chloride, silicone resin, rubber, polyurethane, polycarbonate, epoxy resin, PPO, nylon, polyacetal resin, ABS, phenol resin, etc. according to the intended use and characteristics What has been done is used. For example, vinyl chloride is suitable as a binder resin used for white antistatic flooring materials and wallpapers, and as a binder material for electronic product packaging used for the purpose of electromagnetic wave shielding and preventing electrostatic damage.
Those used for ABS and PPO are suitable. Further, in order to obtain a white antistatic coating material, a semiconductor film for electrostatic recording, and the like, epoxy resin, polyurethane, vinyl acetate resin or the like may be used.

The filling amount of the conductive filler to the resin described above varies depending on the intended use and the degree of conductivity, but is usually 10 to
It is about 90% by weight, preferably about 30 to 70% by weight. If the filling amount is less than the above range, the desired conductivity cannot be obtained, and if the filling amount is more than the above range, problems such as deterioration of whiteness and processing characteristics of the resin occur.

In producing the white conductive resin of the present invention, when the desired whiteness cannot be obtained only by the conductive filler and the binder resin, white inorganic pigments such as titanium oxide, zinc oxide and tin oxide are added to adjust the whiteness. There is no problem in improving it. At this time, it is desirable that the white pigment itself has high light resistance, and titanium dioxide has a higher light resistance than the anatase type.
A rutile type and a white pigment having a surface coated with silica or alumina and improved light resistance are suitable for the use of the present invention.

No special method is required to obtain the white conductive resin composition of the present invention using the above-mentioned materials, and ordinary paints, films, or plastic molding techniques are used. For example, when a thermoplastic resin is used as a binder resin, a conductive filler and a white pigment are kneaded with a resin by a ribbon blender or a heat roll, and then formed into a film by a calendar method or a T-die method, or an injection molding machine. Therefore, it can be processed into a desired shape and used. Further, when a white conductive resin composition is prepared using polyurethane as a resin, if an organic solvent such as dimethylformamide or methyl ethyl ketone and a resin, a conductive filler, a white pigment, etc. are kneaded using a three-roll mill. Can be easily obtained. The paint thus obtained is
It is possible to form a film by drawing the coating film using an applicator, a gravure proofer or the like and drying and removing the solvent.

During these molding processes, within a range that does not impair conductivity, whiteness, light resistance, etc., an antioxidant, an ultraviolet absorber,
Plasticizers, lubricants, surface treatment agents or various conventionally used conductive materials such as conductive zinc oxide, carbon fiber, stainless fiber, conductive potassium titanate, conductive titanium oxide, etc. There is no problem in using things to exert their functions.

(Example of the invention)

The white composite sheet for electrostatic image display capable of being reproduced and displayed according to the present invention will be specifically described below with reference to examples.

Example 1 133 parts of polyurethane (Pendex T-5265L, manufactured by DIC) having a solid content of 30% by weight and a coating metal composition of 86.8% by weight of tin,
Fibrous titanium dioxide with conductivity of antimony 12.9% by weight and cobalt 0.3% by weight (acicular ratio 30-100, long axis 3
~ 6μm) 15 parts and titanium dioxide (R-5N manufactured by Sakai Chemical)
45 parts were kneaded together with 60 parts DMF to prepare conductive paint A.

Example 2 133 parts of polyurethane having a solid content of 30% by weight (manufactured by DIC, Vendex T-5265L) and a coating metal composition of 89.5% by weight tin,
18 parts of fibrous potassium titanate (acicular ratio 30 to 100, long axis 10 to 20 μm) with conductivity of antimony 10.3 wt% and cobalt 0.2 wt% and conductive granular titanium dioxide (W, Mitsubishi Metal) 2 Parts and titanium dioxide (Sakai Chemical, R-5
N) 40 parts was kneaded with 60 parts DMF to prepare conductive paint B.

Example 3 Polyurethane having a solid content of 30% by weight (PC-14, manufactured by Hitachi Chemical Co., Ltd.)
CL) 100 parts with coating metal composition tin 87.8% by weight, antimony 1
Conductive paint by kneading 25 parts of muscovite (flakes diameter 20 μm, thickness 3 μm) and titanium dioxide (R-5N made by Sakai Chemical Co., Ltd., R-5N) of 1.8% by weight and cobalt 0.4% by weight with conductivity of 40 parts by weight of DMF. C was prepared.

Example 4 Polyethylene resin (Sumitomo Chemical, Sumikasen G701) 40
Parts and coating metal composition tin 89.5 wt%, antimony 10.3 wt%, cobalt 0.2 wt% fibrous potassium titanate (acicular ratio 30 to 100, long axis 10 to 20 μm) 40 parts and titanium dioxide with conductivity added. (Ishihara Sangyo, C-R80) 20 parts at 120 ℃
Kneaded with a heat-pressed semiconductor sheet D with a thickness of 3 mm
I got

Comparative Example 1 30% by weight of polyurethane (DIC, Pendex T
(-5265L) 133 parts and conductive potassium titanate fiber (manufactured by Otsuka Chemical, Dentol WK-100, needle ratio 20-100, long axis 10-20)
μm) 20 parts and titanium dioxide (manufactured by Teikoku Kako, JI-1) 40
Parts were kneaded with 40 parts of DMF to prepare conductive paint E.

Comparative Example 2 133 parts by weight of solid content polyurethane (Sumitomo Bayer Urethane, NH-8002) and conductive titanium dioxide fiber (Otsuka Chemical Co., Ltd., WK-200, needle ratio 20-100, long axis 10-20 μm)
30 parts of titanium dioxide and 30 parts of titanium dioxide (manufactured by Teikoku Kako, JA-1) were kneaded together with 30 parts of toluene to prepare a conductive paint F.

Comparative Example 3 50 parts of polyethylene resin (Ace Polymer, Ace Poly HD) and conductive titanium dioxide fiber (Ishihara Sangyo, FT
70 parts of 1000 needle-shaped ratio 30 to 100, long axis 3 to 6 μm) were kneaded at 150 ° C., and a semiconductor sheet G having a thickness of 3 mm was obtained by hot pressing.

Example 5 A semiconductor film having a thickness of 50 μm was prepared using the conductive coating materials obtained in Examples 1 to 3 and Comparative Examples 1 and 2. These films and the semiconductor sheets prepared in Example 4 and Comparative Example 3 were placed on the glass surface of UNICC-33H (manufactured by Toyo Seiki Seisakusho Co., Ltd.) and the whiteness (L value) thereof was measured. In addition, a 45 x 45 x 20 cm black box with a fluorescent light (Toshiba, Mellouc 15W) installed as a light source was installed at a distance of 3 cm from the semiconductor fill and sheet light source, and light irradiation was performed for 5 hours to obtain the initial color tone and light. The color difference (ΔE) was determined from the color tone after irradiation, and the light resistance was evaluated. Further, the surface resistance of each semiconductor film and sheet was measured using a surface resistance meter (HIRESTA, manufactured by Mitsubishi Petrochemical Co., Ltd.). The results of these tests are shown in Table-1.

[Inventive effect] As described above, the white conductive resin composition of the present invention is excellent in whiteness and light resistance, can be freely colored, and maintains stable conductivity in the semiconductor region. When used as a protective film, an electromagnetic field shield material, or a material for electrostatic recording, a beautiful product can be provided.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C08L 29/04 LGM C08L 29/04 LGM 33/04 LHU 33/04 LHU 55/02 LMB 55/02 LMB 61/02 LNX 61/02 LNX 61/04 LMS 61/04 LMS 63/00 NLD 63/00 NLD 69/00 KKP 69/00 KKP 71/12 LQN 71/12 LQN 75/04 NGE 75/04 NGE 77 / 00 KLD 77/00 KLD 83/00 LRX 83/00 LRX 101/00 101/00 C09D 5/24 PQW C09D 5/24 PQW G03G 5/02 101 G03G 5/02 101F H01B 1/20 H01B 1/20 A H05K 9/00 H05K 9/00 X (72) Inventor Masayoshi Suzue 463, Kagasuno, Kawauchi-cho, Tokushima City, Tokushima Prefecture In the Tokushima Research Laboratory, Otsuka Chemical Co., Ltd. (72) Takuro Morimoto Kyo 5-16 Momoyama Yosai, Fushimi-ku, Kyoto (72) Inventor Koichiro Sagawa 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Ajinomoto Co., Inc. Central Research Laboratory (72) Nobuyoshi Kitamura Kawasaki, Kawasaki-shi, Kanagawa 1-1, Suzuki-cho, Tokyo Central Research Laboratory, Ajinomoto Co., Inc. (56) Reference JP-A-2-149424 (JP, A) JP-A-61-261498 (JP, A) JP-A-62-181371 (JP, A) JP-A-63-215745 (JP, A)

Claims (4)

(57) [Claims] 1. A surface of a white or light-colored substrate is covered with oxides of tin, antimony, and cobalt, and the ratio of tin in the composite oxide film is 90 to 85%, and the trace components are antimony oxide and A white conductive resin composition containing a white conductive material, which is cobalt oxide, in a binder resin in a range of 10 to 90% by weight. 2. The ratio of antimony in the composite oxide film is
The white conductive resin composition according to claim 1), wherein the content of cobalt is 10 to 15% by weight and the ratio of cobalt is 0.05 to 1% by weight. 3. The white conductive resin composition according to claim 1, wherein the white or light-colored substrate is a scaly or plate-like or fibrous substance. 4. The binder resin is polyethylene, polypropylene, polystyrene, vinyl acetate, vinyl chloride, silicone resin, rubber, polyurethane, polycarbonate, epoxy resin, PPO, nylon, polyacetal resin, AB.
The white conductive resin composition according to claim 1, which is at least one selected from S, phenolic resins, and acrylic acid esters.