JPS59193936A - Filler for resin - Google Patents

Abstract

PURPOSE:To obtain titled filler with little drop in conductivity even after incorporation, by coating, under an inert gas atmosphere, a specific organic compound on the suface of a conductive oxide powder. CONSTITUTION:The objective filler can be obtained by coating, under an inert gas atmosphere, on (A) a condutive oxide (pref., n type semiconductive one prepared by incorporating ZnO, SnO2 or TiO2 with a higher-valent oxide; for example, ZnO-Al2O3, SnO2-Sb2O3) powder surface (B) 0.01-1.0wt%, based on said oxide powder, of an organic compound (pref., fatty acid, alcohol).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fillers for resins. More specifically, the present invention relates to fillers for resins that exhibit little decrease in conductivity even after being kneaded into resins.

In recent years, methods of kneading and dispersing conductive fillers in resins such as rubber and plastics to impart 111 radiation prevention or electromagnetic wave shielding ability to the resins have been studied. Graphite, aluminum, copper, nickel, etc. are used in various forms such as powder, fiber, and foil.

However, when the filler described in "2" is kneaded and dispersed in a resin, it is colored darkly, making it difficult to obtain molded products with bright colors such as white.

Therefore, 5b203, Al2O3, 1r1203 is added to white oxides such as 5n02, ZnO or I'i02.
It has been proposed to use a conductive oxide powder that is white, pale blue, or has a pale color with a thin border color. (For example, Z
n OA 7!2o3 U.S. Patent No. 3538022, U.S. Patent No. 3538023 and S n 02-3 b203
However, since these oxides are light-colored, although they have the advantage of being able to optionally color the w-body resin using them, it is difficult to incorporate the oxides into the resin. When it is kneaded to form a conductive resin, it has the fatal drawback of significantly lowering the conductivity.

In order to solve this drawback, the present inventors carried out intensive tests on δ・1, and found that the decrease in conductivity of the conductive oxide during resin filling is due to the oxidation during kneading with the resin. Alternatively, it is assumed that this is due to physical changes in the surface of the oxide powder due to friction between the oxide powder and the resin, as well as the equipment that stirs and kneads them. It has been discovered that the conductive oxide powder obtained by coating with the above-mentioned material can solve the above-mentioned problems, and the present invention has been completed.

Zunawaji, the present invention provides a resin filler characterized in that the surface of conductive oxide powder is coated with an organic compound in an amount of 0.01 to 1.0% by weight based on the amount of oxide in an inert gas atmosphere. There is something to do.

Hereinafter, the present invention will be explained in more detail.

The conductive oxide that forms the base of the resin filler of the present invention may be any known white or light-colored conductive oxide that can impart conductivity by filling and dispersing and kneading it into the resin. The type is not particularly limited, but for example, ZnO
, SnO□ or TiO2 from these metal oxides, I;41 valence oxide, for example, 5b2 as a raw material powder
03, A et al. 03, I n203, G e 02
S n O2-S
In the case of n-type semiconductor oxides such as b203 and ZnO-A1.03, the effect of preventing a decrease in conductivity is particularly remarkable.

On the other hand, the organic compound used for coating the conductive oxide powder is one that covers and protects the surface of the oxide powder during kneading, has a decomposition temperature lower than that of the base polymer compound, and
Materials that do not carbonize or foam significantly during heat treatment are required, and such materials include lauric acid,
Fatty acids such as stearic acid, aluminum stearate,
Salts of fatty acids such as zinc stearate, albinols such as chrycerin, ethylene glycol, and ethanol, amines such as triethanolamine, coupling agents such as nathanate cassoplating agents, silicate coupling agents, and silicone oils. For example, it may be dissolved in alcohol, alcohol, liquid hydrocarbon, etc., and coated on the surface of the oxide powder.

Even after the organic compound is coated on the surface of the conductive oxide powder, it remains on the oxide surface and exhibits a high electrical resistance value, which is not preferable because it has the opposite effect.

It is essential that the coating treatment of the organic compound on the surface of the oxide powder be carried out under an inert gas atmosphere.

The inert gas used may be any commonly used inert gas, and nitrogen gas is commonly used for economic reasons. The conductive oxide obtained when the treatment is carried out in an oxygen atmosphere does not exhibit the effect of preventing a decrease in conductivity when kneaded into a resin. During the treatment, the oxygen concentration in the inert gas is not unique depending on the type and amount of organic compound used for surface treatment of the oxide powder, but generally the oxygen concentration is 1% or less, preferably 0. 1%
It may be carried out within the following range.

Why does the resin filler of the present invention obtained by coating the surface of conductive oxide powder with an organic compound under an inert atmosphere exhibit a phenomenon of decreased conductivity even after being dispersed in a polymer compound and kneaded? The reason for this is not clear; one reason is that the surface electronic structure changes due to IKi during kneading of the oxide powder as mentioned above, and the other is that the oxidation occurs after filling the oxide powder into a polymer compound. Heat treatment is performed for the purpose of fixing substances in a polymer compound, but this treatment causes oxidation and polymer compounds to form in the oxygen defects or electron-rich layer of the lattice points, which is the side that exhibits conductivity of the oxide. Oxygen present in the gaps adsorbs negative charges, which lowers the conductivity. However, by coating this with an organic compound and performing the treatment under an inert atmosphere, changes in the electronic structure of the oxide surface can be achieved. It is presumed that this is because it can prevent the development of the preventive effect and the adsorption of negative charges.

The conductive filler for resin obtained in this way can be dispersed and kneaded in PB + fat using the usual resin blend method.
, ; As the resin that becomes the y-body, polyethylene, Volip 1
Thermoplastic resins such as 11-pyrene, hinyl chloride, polyamide 1-, polystyrene, fluororesin, urea (thermosetting resins such as Δj resin, melamine resin, phenol resin, epoxy resin, unsaturated polyester, alkyd resin, etc. + A4 resin, styrene resin) The type of filler is not limited as long as it is a synthetic rubber such as butadiene comb, natural comb, etc. that is used in the relevant field.The amount of filler to the resin varies depending on the type of resin, but is generally about 5 to 100% by volume. Appropriate.

As detailed above, according to the present invention, the conductive oxide obtained by coating the surface of the conductive oxide powder with an organic compound in advance in an inert atmosphere is added to the polymer compound in 11 parts.
Even when kneaded and heat treated, the filler does not show any decrease in conductivity compared to kneaded OiI, and its industrial utility value is extremely high.

Hereinafter, the present invention will be further explained with reference to examples, but the present invention is not limited by these examples.

Example 1 100 parts by weight of zinc oxide, 3.5 parts by weight of aluminum nitrate, and 50 parts by weight of water were mixed into a paste and dried.
Specific resistance as powder is 1Ω when heated in hydrogen at 0℃ for 2 hours.
Conductive oxide of C1n (4.

This filler was coated with stearic acid, which was adjusted with ethanol to the coating amount shown in Table 1.

The conductive filler obtained in this way is added to various polymer compounds.
Filled with 5% volume II and heat treated in air, 50X
A 50 x 50 + un sample was molded. The conductivity of the obtained sample was measured. The results are shown in Table 1. still,
For comparison, a resin filler in which the filler was coated in air with an ethanol solution of stearic acid and a resin filler without exposure treatment were similarly filled into a polymer compound and processed; The conductivity of the treated material was measured. The results are also included in Table 1.

Table 1 From Table 1, it can be seen that when the amount of organic compound coated on the fat is too high, or when the treatment is carried out in air, the effect of preventing conductivity from decreasing is not observed; In this case, it can be seen that the conductivity has decreased significantly.

Example 2 Similar to Example 1, filler for conductive resin (not shown in Table 2) was used.
The electrical conductivity of the electrically conductive resin obtained under the conditions shown in the table was measured using a polyhydric compound (15% by volume based on the resin) and a polyhydric compound. The results are shown in Table 2.

Claims (1)

[Claims] (1) A filler for resin, characterized in that the surface of the conductive oxide powder is coated with an organic compound in an amount of 0.01-1.0% by weight based on the amount of the oxide in an inert gas atmosphere. . 2) The conductive oxide is ZnO, 5n02, or 'I''i
The resin filler according to claim 1, which is an n-type semiconductor oxide obtained by coexisting an oxide with a higher valence than these metal oxides in 02. 3) The resin filler according to claim 1, wherein the organic compound is at least one of a fatty acid, an alcohol, a salt of a fatty acid, an amine, a titanium I coupling agent, a silicate coupling agent, and a silicone oil.