JPS626506B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to plastic films, and more particularly to antistatic plastic films. Since plastic films are generally electrically insulating, they accumulate static electricity when they come into contact with various substances, cause friction, or peel off during manufacturing or use. This accumulated static electricity causes many problems. Static electricity can cause dust to adhere to the surface, or give a strong electric shock to the user, or in severe cases, it can discharge, igniting flammable materials, and causing a disaster. Furthermore, in photographic film, discharge traces become so-called static marks, which are fatal defects. The present invention relates to a substantially transparent plastic film that is antistatic to eliminate these electrostatic charge disturbances. The substantially transparent plastic film of the present invention can be used as supports for recording materials such as silver halide photographic supports, electrophotographic supports, and magnetic film supports, as well as for packaging, drafting, and moving images. It is suitable for various film applications such as. There are two ways to prevent static electricity on plastic film: one is to knead the antistatic agent into the plastic film, and the other is to apply it to the surface of the film. However, the method of kneading an antistatic agent does not require a large amount of antistatic agent to be mixed in. It has little effect, and when added in large amounts, it often impairs the mechanical properties of the plastic film or impairs its transparency. The method of coating the plastic surface is to apply a polymer substance or surfactant as an antistatic layer, to apply a conductive substance such as carbon or metal powder as an antistatic layer, or to apply a metal or metal oxide as an antistatic layer. Methods of vapor deposition are well known. The polymeric substances and surfactants used as antistatic agents are described in detail in Hideo Marumo's ``Antistatic Agents'' (Saiwai Shobo), but these polymeric substances and surfactants should be used before application. Although it is easy to use, the conductivity is humidity dependent and the antistatic performance at low humidity is poor. Carbon and metal powders make the antistatic layer opaque, making them unsuitable for preventing static electricity on plastic films that require transparency.
Additionally, adding large amounts of metal powder or carbon to increase conductivity deteriorates the mechanical strength of the antistatic layer.
In particular, it causes deterioration in abrasion properties. On the other hand, so-called vapor-deposited transparent conductive films are known in which tin-doped indium oxide or antimony-doped tin oxide is vapor-deposited (for example, 18440 (1980)), but these have the drawbacks of complicated manufacturing methods and high costs. However, it also has the disadvantage of poor abrasion resistance. A first object of the present invention is to provide a plastic film with antistatic properties. A second object is to provide a substantially transparent, antistatic plastic film. The third object is to provide a plastic film that has excellent antistatic properties even in low humidity conditions. A fourth object is to provide a plastic film having an antistatic layer with excellent mechanical strength. These objects of the present invention include Zn, Sn, In, Si,
The volume resistivity is 10 ⁷ Ω・cm or less, which is mainly composed of an oxide of at least one metal selected from Mo and W and/or at least one metal composite oxide composed of oxides of these metals. with an average particle size of 0.2μ
This was achieved by a plastic film characterized by having at least one layer containing conductive fine particles and at least one coupling agent selected from the following: titanium coupling agents and silane coupling agents. It has been found that conductivity can be achieved even at low humidity by using fine particles of crystalline metal oxides and/or composite oxides. Japanese Patent Publication No. 35-6616 describes a technology using tin oxide as an antistatic treatment agent, but this technology uses amorphous tin oxide colloid, and its conductivity is dependent on humidity. Therefore, the conductive layer does not function adequately under low humidity. The crystalline metal oxide or composite oxide fine particles used in the present invention have a volume specific resistivity of
It is 10 ⁷ Ω-cm or less, more preferably 10 ⁵ Ω-cm or less. The particle size of the crystalline metal oxide particles used in the present invention is preferably small in order to minimize light scattering, but is determined using the ratio of the refractive index of the particles and the binder as a parameter.
Therefore, the particle size varies depending on the fine particles and binder used, but the particle size is preferably 0.01 to 0.7μ.
Substantially transparent films can be obtained by using particles of 0.02 to 0.5 microns. The method for producing conductive crystalline metal oxide or composite oxide fine particles used in the present invention is described in detail in Japanese Patent Application No. 1983-47663. A method in which metal oxide fine particles are produced by firing and heat treated at the bottom left where foreign atoms are present to improve conductivity.Secondly, a method in which metal oxide fine particles are produced by firing and in which foreign atoms coexist in order to improve conductivity.Third. When producing metal fine particles by firing, the oxygen concentration in the atmosphere is lowered,
There are methods such as introducing oxygen vacancies. Examples containing different atoms include Al and In for ZnO.
Nb, Ta, etc. for etc., Sb for SnO ₂ , etc.
Examples include Nb and halogen elements. The amount of foreign atoms added is preferably in the range of 0.01 to 30 mol%, but 0.1 to 30 mol%.
Particularly preferred is 20 mol%. The silane coupling agent used in the present invention is commercially available from Shin-Etsu Silicone Co., Ltd., and is as follows. Compound example: []CH ₂ = CHSi(OC ₂ H ₄ OCH ₃ ) ₃ [] [] []H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si(OCH ₃ ) ₃ [] [] (CH ₃ O) ₃ SiC ₃ H ₆ NHC ₂ H ₄ NHCH ₂ COOH [] (CH ₃ O) ₃ SiC ₃ H ₆ NHC ₂ H ₄ NHCH ₂ CH=CH ₂ Titanate coupling agents include, for example, Ajinomoto ( It is commercially available from Co., Ltd. and is as follows. Compound example: [] [] [] [XI] ( _{C8H17 -} O)-Ti・[P(-O- _C13H27 ) _2OH ] _2If these coupling agents are dispersed and applied in a binder together with conductive metal _oxide fine particles, good. The amount of these coupling agents added varies depending on the type of conductive particles and particle size and binder, but is preferably from 0.05% to 20% of the conductive metal oxide, preferably from 0.1% to 10%. (% by weight) The binder may be any polymer commonly used for coatings, such as cellulose esters such as cellulose acetate, cellulose nitrate, cellulose acetate butyrate, and cellulose propioenate, soluble polyester, polycarbonate, soluble nylon, Polyvinyl chloride, vinyl chloride-containing copolymers,
Polyvinylidene chloride, vinylidene chloride-containing copolymers, polystyrene, styrene-containing copolymers, polyvinyl acetate, vinyl acetate-containing copolymers, alkyl acrylate-containing copolymers (alkyl groups C ₁ -
C ₄ ) etc. can be raised. Examples of solvents for these binders include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, and glycol monoethyl acetate ether, glycol dimethyl ether, and glycol monomethyl. Glycol ethers such as ether, glycol monoethyl ether, and dioxane; aromatic hydrocarbons such as benzene, toluene, and xylene;
Chlorinated hydrocarbons such as methylene chloride, ethylene chloride, chlorocene, trichlene,
Examples include alcohols such as methanol, ethanol, propanol, butanol, dimethylformamide, dimethyl sulfoxide, and phenol. The amount of conductive particles used is preferably 0.05 g to 20 g, preferably 0.1 g to 10 g, per square meter of plastic film. The conductive fine particles may be one type of metal oxide or two or more types. Further, the metal composite oxide may be used alone or a combination of the metal oxide and another composite oxide may be used. There is no problem in adding a slipping agent, a matting agent, etc. to this layer. Plastic films that can be used include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyethylene,
Polyolefins such as polypropylene, cellulose esters such as cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate, nitrocellulose, vinyl plastics such as polyvinyl chloride, polyvinylidene chloride, and polystyrene. , polycarbonate, polyimide, polyamideimide, etc. Applications of the plastic film of the present invention include supports for silver halide photographic materials, supports for electrostatic photography, films for drafting, and the like. The present invention will be made more specific by Examples and Comparative Examples below, but the present invention is not limited to the following Examples. In the following examples, all "parts" indicate "parts by weight." Example 1 65 parts by weight of stannic chloride hydrate and 1.5 parts by weight of antimony trichloride were dissolved in 1000 parts by weight of ethanol to obtain a homogeneous solution. A 1N aqueous sodium hydroxide solution was added dropwise to this solution until the pH of the solution reached 3 to obtain a coprecipitate of colloidal stannic oxide and antimony oxide. The resulting coprecipitate was left at 50°C for 24 hours to obtain a reddish brown colloidal precipitate. A reddish-brown colloidal precipitate was separated by centrifugation. In order to remove excess ions, water was added to the precipitate and the precipitate was washed with water by centrifugation. This operation was repeated three times to remove excess ions. 100 parts by weight of the colloidal precipitate from which excess ions had been removed was redispersed in 1000 parts by weight of water and sprayed into a calcining furnace heated to 600°C to obtain a fine powder with a bluish tint and an average particle size of 0.2 μm. The volume resistivity of this powder was 8 Ω·cm. Using the above powder, liquids () and () having the following compositions were dispersed in a ball mill. [] [] Above powder 65 65 Coupling agent for compound example [] 1.3 0 Cellulose diacetate 10 10 Acetone 900 900 Cyclohexanone 400 400 The above dispersion was mixed with vinylidene chloride copolymer (vinylidene chloride/ethyl acrylate/acrylic acid).
85:10:5 copolymer) was coated to a thickness of 0.2μ on a 180μ thick PET support so that the dry thickness was 0.3μ and dried at 150°C for 5 minutes. The surface resistivity and scratch hardness of the coated surface of this film were as follows.

[Measurement of scratch hardness]

: Place a diamond needle with a tip diameter of 50μ on a horizontally placed sample, and move it by 1cm/1cm while changing the load.
It was moved at a speed of seconds, the load at which scratches began was read, and that value was taken as the scratch hardness value. The larger the value, the better the scratch resistance. Example 2 Using the same conductive tin oxide fine powder as in Example 1, dispersions [] and [] having the following compositions were prepared. [] [] The above powder 80 80 Compound example 2 0 Nitrocellulose 10 10 Acetone 300 300 Methyl ethyl ketone 900 900 Nitrile rubber 2 2 This dispersion was applied to a 127μ thick cellulose triacetate film to a dry film thickness of 0.3μ, It was dried at 130°C for 20 minutes. The surface resistivity and scratch hardness were as follows.

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Claims (1)

[Claims] 1 Mainly composed of an oxide of at least one metal selected from Zn, Sn, In, Si, Mo, and W and/or at least one metal composite oxide composed of oxides of these metals. Volume resistance is 10 ⁷ Ω・
1. A plastic film comprising at least one layer containing conductive fine particles having an average particle size of 0.2 μm or less and at least one coupling agent selected from a titanium coupling agent and a silane coupling agent.