JPS6232145A - Transparent, electrically semiconductive material - Google Patents

Abstract

PURPOSE:To form simple a transparent, ellectrically semiconductive material without detriment to the characteristics inherent to resins, by doping a polyurethane sheet or film with a specified dopant. CONSTITUTION:The titled electrically semiconductive material which is transparent and has a volume resistivity of 10OMEGA.cm or below is obtd. by doping a film or sheet prepd. from a polyester or polyther polyurethane material with halogen atom and/or hydrogen halide. The material has a thickness of pref. 2mm or below, and a sheet or film of 50mu or below is particularly preferred when the thickness is 2mm or above, no sufficient doping effect can be obtd. The preferred halogen atom is iodine atom, because doping in a soln. form can be carried out. A preferred doping method is one wherein the material is dipped in a soln. contg. a dopant.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention relates to a transparent and semiconductive polyurethane resin material.

(B) Conventional technology Conventionally, as a material in which conductivity is added to a general resin without using a resin with a special structure, conductive filler such as carbon black or metal is kneaded into the resin material. There are dispersion spoons (D-dispersed composite conductive materials (for example, "Surface" Vol. 13 No. 8 t--August 1975, "Conductive Polymers and Their Utilization" by Mizome et al.). There are polymer semiconductors that make the molecular structure of the polymer itself a good conductor of electrons, and more recently, the above (i) has been modified to include electron acceptors (halogens, Lewis acids, etc.) and electron Materials with semiconductivity or conductivity close to that of metals have been developed by doping without impregnation with dopants (dopants) of donors (alkali metals, tetrabutylammonium, etc.) Volume 40, No. 5,
May 1975 issue [Conductive polymers as new functional materials] Yoshino). Furthermore, conductive materials have also appeared in which a metal material is integrated on one side of a transparent synthetic resin sheet or film by vapor deposition, coating, etc.

(C) Problems to be Solved by the Invention However, except for the fact that the material (D) is given conductivity, the kneading process takes time to form the top layer E; The original physical properties of the resin,
Changes in chemical properties, deterioration of mechanical strength (for example, becoming opaque, loss of flexibility and brittleness), etc.
In addition, non-uniform filling of the filler occurs, and it is difficult to obtain a material with a uniformly low volume resistivity, so that a transparent and conductive material has not been obtained.

In addition, the material r1 of (fi) requires special characteristics in its structure and has excellent conductivity, but the crystal itself is not transparent, and even with doping, it cannot be achieved deeply in the thickness direction. Therefore, it was a national problem to find a material with a low resistivity as a conductor for the desired thickness. Furthermore, the material (2) has the serious problem that only its surface resistance has been improved, which limits its use and that it lacks transparency.

As mentioned above, to the best of the knowledge of the inventors of the present invention, there has been no known conductive material that is transparent and has a volume resistivity of 10'' Ω·C or more.

In view of this point, Honbon Akashi et al. have conducted extensive research, and as a result,
We have discovered that a conductive material that is transparent and has a volume resistivity of 10°Ωcm or less can be easily obtained by simply doping a known resin with a dopant, without impairing any of the resin's inherent properties. , has completed this invention.

(d) Means and action for solving the problems Thus, according to the present invention, the material is polyester-based or polyneedle-based polyurethane doped with halogen atoms and/or halogenated water, and has a volume resistivity of 10°Ω·m or less. A transparent semiconducting material is provided which is characterized in that it is transparent.

Transparency in this invention means 50% natural light transmittance.
This means the above.

Furthermore, the term "semiconductivity" used in this invention refers to volume resistivity. It is preferable that the value is 10 8 Ω·C or more.

The polyurethane of the rope H, which is the subject of this invention, may be hard, semi-hard, or soft, with an average molecular weight of several thousand to several tens of thousands of ω, and polyester-based or polyether-based polyurethane is suitable. As the polyester, hydroxyl polyester is suitable because the main purpose is to avoid reaction between isocyanate and Da-OH, which is the final product of the polyester. Transparent human [1-xyl polyesters] synthesized from BIM such as phthalic acid, adipic acid, and maleic acid, and diols such as ethylene and propylene, and triols such as glycerin and trimethylolpropane are available. Preferable from the viewpoint of sex. On the other hand, the polyether used is a terminal hydroxyl polyether, and polyether polyols of propylene oxynide, ethylene oxide, or a copolymer of both are preferred from the viewpoint of transparency.

Other polyurethane resins having properties suitable for the field in which they will be used as final products are appropriately selected and utilized. Mogolon (registered trademark, manufactured by Nisshinbo Co., Ltd.) is an example of a commercially available polyurethane resin.

In this invention, the polyurethane resin is usually used in the form of a sheet or film, or in the form of a belt depending on the desired use. The thickness is suitable for use as a sheet or belt, and is 9 mm or less.
00μ or less is preferable.

Further, from the viewpoint of use as a special film for substrates such as optical sensors and semiconductors, the thickness is preferably 0.1μ or more. Note that when the thickness of the material is 2 mm or more, doping will be insufficient and it is not suitable.

In this invention, the dopant J3 that imparts conductivity is:
Halogen atoms and/or hydrogen halides are suitable.

As for the halogen, an iodine atom is preferable since it enables doping in a solution state.

The method of doping the polyurethane resin material with the above-mentioned dopant is 1) a method of exposing to a dopant gas, and 2) a method of dipping in a solution containing the dopant. 3) electrochemical method, 4) ion plantation, etc., and any of the above methods may be used in this invention,
The dipping method 2) is most suitable because it does not impair the properties of the polyurethane resin used as the material and can be carried out easily.

33 In this invention, the doping liquid used for dipping is one in which the above-mentioned Dobans 1 to 1 are dissolved in a solvent, and suitable solvents are those that do not alter the quality of the polyurethane resin material, such as methanol, acetone, glycerin, Examples include ethylene glycol and water. The temperature at this time must be adjusted to a concentration that does not impair the transmittance. Further, when preparing a doping solution using a halogen as a dopant, an alkali metal salt of the halogen may be mixed. However, the mixing ratio is preferably QP mole or less relative to the halogen.

The material of this invention can be obtained in seconds by dipping the material into the doping solution.

The suitable temperature for this scouring is room temperature to the boiling point of the solvent, and the pressure is preferably normal pressure or higher. For example, Mobilon P-27.1'
-241 registered trademark, manufactured by Nisshinbo Co., Ltd.) film (thickness: 400 μm) is dipped in a 0.2 M iodine-methanol solution at room temperature and pressure, doping is achieved in a few dozen seconds. However, the thickness of the material
The time required for doping varies depending on the surface area, etc.

The material of the present invention obtained by the above method is transparent and has a volume resistivity of 106, although it is slightly colored by the dopant.
It has a value of ~10" Ω・cm, and this is achieved by first forming a specified polyester or polyether urethane material into a sheet or belt shape with a desired thickness using a known molding method. After that, the product obtained by doping as described above is coated with a conveyor belt for a copying machine (required Sarel volume resistivity 106 to 10 tlΩ・Cl1).
1) Driving bells for VTRs, tape recorders, players, etc. (106 to 109 Ω cIQ), static removal blades for copiers (106 Ω cm or less), antistatic rollers (107 to 109 Ω cIQ) 109Ω・crn)'4.

At present, it is not clear why the volume resistivity decreases when polyurethane resin is doped with iodine atoms. However, in the structure of polyurethane resin, a π-conjugated system exists between the lone pairs of nitrogen and oxygen atoms resulting from the (+) urethane bond and the π electrons of the carbonyl double bond existing between them. that may occur;
(ii) Lone pair of oxygen atoms in polyester and π electrons of carbonyl double bonds or lone pairs of oxygen atoms in polyneedle, etc. There are many electrons that can participate in π-conjugated systems, and there are many scales and 0 voids. It is possible that doped iodine atoms interact by being located in voids or between localized π-conjugated systems or by forming complexes on specific atoms, resulting in long π-conjugated systems. It is thought that the interval between the ground state and the excited state of the π electrons involved in this becomes narrower, and a large group of electrons are thermally excited, resulting in the resin as a whole exhibiting constant semiconductivity.

Note that among the polyether-based and polyester-based polyurethane resins used as raw materials, polyether-based polyurethane resins are preferred. The reason for this is that due to the free rotation and polarization due to the presence of the ether group (-On) in this resin, when the cation X and the iodonium ion (I3)- are used, there is a static The electric attraction weakens, and mobility X◆ appears.This X◆ weakly interacts with ether oxygen in the resin, and this causes gaps (free volume) in the resin.
This is because it is thought that the cations move toward
This is because conductive anions and neutral molecules tend to approach each other intermolecularly due to high polarity and low glass transition point, which is thought to increase the resistance value.

The feature of this invention is that the transparent resin can be instantly doped by a simple method, and the volume resistivity can be reduced to 10°.
It has a semiconductivity of Ω·Cl11 or less, and the transparency and other characteristics inherent in the resin material are not impaired even after doping.

(B) Examples The present invention will be explained in detail with reference to Examples below, but the present invention is not limited thereto.

Example 1 Polyether polyurethane resin Mobilon p-2711
registered trademark, manufactured by Nisshinbo Co., Ltd.) film (thickness 400μ
) was cut into pieces of 14.90 (1), both sides of which were thoroughly wiped with methanol and left in a desiccator for 30 minutes to prepare a sample for doping. On the other hand, the doping solution was prepared by weighing out 0.8182 (l) of iodine (first class reagent) and dissolving it in 45 cc of methanol to prepare a 0.07 M iodine-methanol solution.The previously prepared film was placed in the above solution. After dipping and doping, the sample piece was taken out, dried, and the ends were sandwiched between 1 mm square aluminum electrodes to measure the volume resistance between the front and back sides of the sample piece with a voltage of 100 VDC. A similar experiment was carried out five times with different doping times and the results shown below were obtained.

(The volume resistivity of the Mobilon film itself is 10
A one of °Ω・1 was used. ) (The following is a margin, continued on the next page) In addition, the sample piece subjected to the above doping was measured with a photometer (Shima t, 1 UV-visible spectrophotometer UV-160, ■ Shima t-1 t).
When measured using the IJ Manufacturing Co., Ltd., the light transmittance was 50% or more in all cases.

Example 2 A sample piece similar to Example 1 was prepared, and the doping solution was iodine (first class reagent) 0.8182 () mixed with methanol 1
Dissolve in 5cc of 0.2M iodine-methanol solution
.

The procedure was carried out in the same manner as in Example 1 except that the one prepared in
The following results were obtained.

Further, when the light transmittance of the sample pieces subjected to the above doping was measured in the same manner as in Example 1, all of them showed 50% or more.

Although it is possible to prepare an iodine-methanol solution with a higher concentration, the above concentration is the upper limit for ensuring a light transmittance of 50% or more.

A sample piece similar to Example 1 was prepared, and the doping solution was a mixture of potassium iodide (K I ) 0.6980 dissolved in 25 cc of methanol and iodine (first class reagent) 0.8
Measurement was performed in the same manner as in Example 1, except that a solution prepared by dissolving 1820 in 45 cc of methanol and mixing both liquids (Kl: I2 = 4:3 molar ratio) was used.
The following results were obtained.

Furthermore, when the light transmittance of the sample pieces subjected to the above doping was measured in the same manner as in Example 1, all of them showed 50% or more.

Example 4 Polyester polyurethane resin, Mobilon F-24 (registered trademark, manufactured by Nisshinbo Co., Ltd.) film (
A sample with a thickness of 400 μm) was used, and it was dried to a temperature of 1°d, and both sides were thoroughly wiped with ethanol and left in a desiccator for 30 minutes to prepare a doping sample R1. This was carried out in the same manner as in Example 1, and the following results were obtained (the volume resistivity of the Mobilon film itself was 1
012Ω・I used the one made by Japan.

Further, when the light transmittance of the sample pieces subjected to the above doping was measured in the same manner as in Example 1, all of them showed 50% or more.

[1] As a comparative example, a 400μ sheet of U12-nylon (Diamid 12 (registered trademark), manufactured by Daicel Kagaku Kogyo: 1ttU) was prepared in the same manner as in Example 1, except that a 400μ sheet was used as a sample piece. However, the results shown below were obtained.

(However, the volume resistivity of the above 12-nylon itself is 10
Ω・Cl11) was used. ) Example 5 As an application example of wood materials, Mobilon pellets of polyale polyurethane resin))-27 (registered trademark, Nisshinbo Co., Ltd. ￥J) were extruded and stretched to a thickness of 400μ.
After preparing the material, it was cut into a predetermined width (230 mm) and formed into an endless belt (periphery: 385 mm) to make a conveyor belt for a PPC copying machine. This was mixed with the same doping solution as in Example 1 (iodine (1st grade test 1) 4,091 (l)
was weighed and dissolved in 225 cc of methanol. 0
．． After drying, the volume resistivity was measured in the same manner as in Example 1. The result is 3X 10'Ω
・It was 1. Moreover, the light transmittance of this was 50% or more.

As is clear from the above Examples 1 to 4 and Comparative Examples, the materials obtained in Examples 1 to 4 are transparent materials that have rapid electrical conductivity according to the present invention, and these Examples This indicates that doping of the material can be achieved instantaneously by immersion for about 15 seconds.

Further, Example 5 shows that the material of the present invention can actually be formed into a sheet or a belt, and can be used as a conveyor belt for a PPC copying machine as an example of its application.

(F) Effects of the Invention As described above, according to the present invention, a semiconductive and transparent material can be easily obtained by simply doping a polyurethane resin. Therefore, since the obtained material does not have any of the characteristics originally possessed by the resin material, a remarkable expansion of its uses can be achieved by providing transparency and conductivity in addition to its original use. For example, conveyor belts for RPC copying machines, drive belts for static electricity control, static removal blades for copying machines, antistatic rollers, photoreceptors (for OPC)
This is an epoch-making material that can be used as a material for charge transfer belts, etc.

Claims (1)

[Claims] 1. The material is polyester-based or polyether-based polyurethane doped with halogen atoms and/or hydrogen halide, and is transparent with a volume resistivity of 10^1^0 Ωcm or less. transparent semiconductive material. 2. The material according to claim 1, which is in the form of a sheet or film with a thickness of 2 mm or less, preferably 500 μm or less. 3. The material according to claim 1, wherein the halogen atom is an iodine atom.