JPH0339379A - Release sheet and tacky tape - Google Patents

Abstract

PURPOSE:To obtain the title sheet for packaging tape, etc., having stably high antistatic properties and excellent adhesion with tacky agent, etc., by forming a thin film of electrically conductive high polymer consisting of polyaniline on an insulating substrate and further forming a parting agent layer thereon. CONSTITUTION:The aimed sheet obtained by forming a thin film 2 of an electrically conductive high polymer consisting of polyaniline on at least either one surface of an insulating substrate and further forming a parting agent layer thereon. Furthermore, the above-mentioned electrically conductive high polymer is a polymer having main recurring units expressed by the formula (m and n are each mol fractions of quinolinediimine structural unit and phenylene diamine structural unit in recurring units and 0<m<1, 0<n<1 and m+n=1) and soluble in an organic solvent in dedope state and preferably is >0.40dl/g in intrinsic viscosity measured in N-methyl pyrrolidone at 30 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a release sheet and an adhesive tape that have antistatic properties by forming a thin film of a conductive polymer made of polyaniline on an insulating base material. Regarding.

Adhesive tapes are generally made by laminating an adhesive layer on one side of an insulating base material and laminating a release agent layer on the other side as required, and are usually supplied for use in rolls. In use, the tape is unwound from the outer end and applied to the desired adhesive surface. However, with conventional adhesive tapes, static electricity is generated in the tape and the tape clings to the hand, making it difficult to work with. Disadvantages include: the body is attracted to the tape and the application position is misaligned; dust adheres to the tape, making it easy to get dirty; and the end of the tape wraps around the roll, making it difficult to find the end of the tape the next time it is used. have.

In order to solve these problems with adhesive tapes, it has been proposed to provide electrical conductivity to adhesive tapes to prevent them from being charged. For example, a method of kneading a conductive substance such as a surfactant, carbon powder, or metal powder into an insulating base material, a method of incorporating a conductive substance such as the above into an adhesive, a method of adding a surfactant to the back of the tape, etc. A method of coating with an antistatic agent, a method of providing an antistatic layer made of an ion conductive polymer between a base material and an adhesive layer as described in JP-A No. 61-272279, etc. Are known.

However, methods of kneading conductive substances such as carbon powder or metal powder into a base material or blending them into an adhesive layer cannot be applied when transparency is required for the adhesive tape. According to the method using a surfactant, the bleeding may impair the adhesion between the base material and the adhesive layer or the release agent layer on the opposite side, so-called anchoring properties, or the adhesive 1f'JN may be contaminated. This may reduce adhesion. In the method of using the above-mentioned ion conductive polymer as an antistatic agent, its performance is easily affected by humidity and water, and especially under low humidity, the surface resistance increases significantly and the desired antistatic ability is lost. In addition, it has poor adhesion with the adhesive layer, that is, poor anchoring ability, and tends to leave adhesive residue when the tape is rewound.

Further, in double-sided adhesive tapes and adhesive labels, a #I release sheet formed by forming a release agent layer on an insulating base material is attached to the adhesive layer and used.

Therefore, when the release sheet is peeled off during use, static electricity is generated on the release sheet, similar to the above-mentioned adhesive tape, resulting in inconvenience.

The present invention solves the above-mentioned problems with conventional release sheets and adhesive tapes, and has excellent adhesion to the adhesive layer and release agent layer. It is an object of the present invention to provide a release sheet or adhesive tape that does not cause contamination and has stable and high antistatic properties regardless of changes in the surrounding environment such as humidity and moisture.

That is, the present inventors have discovered a conductive polymer made of polyaniline that is soluble in organic solvents, can be made into a thin film by casting, and whose conductivity is not easily affected by humidity or water by doping it. , such S
We have discovered that it is possible to obtain release sheets and adhesive tapes with stable and high antistatic performance by forming a thin film of an electrically conductive polymer on a base material and laminating a release agent layer or an adhesive layer thereon. This led to the present invention.

The release sheet according to the present invention for releasing i has a thin film of a conductive polymer made of polyaniline formed on at least one surface of an insulating base material, and a release agent layer is further formed on the thin film of a conductive polymer made of polyaniline. It is characterized by being

Further, the adhesive tape according to the present invention is characterized in that a thin film of a conductive polymer made of polyaniline is formed on at least one surface of an insulating base material, and an adhesive layer is further formed on the thin film of a conductive polymer made of polyaniline. shall be.

Furthermore, another adhesive tape according to the present invention has a thin film of a conductive polymer made of polyaniline formed on at least one surface of an insulating base material, and a release agent layer formed thereon. It is characterized by having an adhesive layer formed on the opposite side.

In the present invention, in the above-mentioned release sheet and adhesive tape, the conductive polymer made of polyaniline has the following form: 0<m<1.0<n<1, m+n=l) as the main repeating unit, is soluble in an organic solvent in a dedoped state, and has N −
Intrinsic viscosity [η] measured at 30°C in methylpyrrolidone
is 0.40 dl/g or more, and 457.9n
Among the skeletal vibrations of para-substituted benzene in the laser Raman spectrum obtained by excitation with light of wavelength m, 1
Ratio 1 of the Raman line intensity 1a of the skeleton stretching vibration occurring at a wave number higher than 600 cm-' and the Raman line intensity 1b of the skeleton stretching vibration occurring at a wave number lower than 1600 cm+-'
It is made by doping organic solvent-soluble polyaniline with a/Ib of 1.0 or more with a protonic acid having a pKa value of 4.8 or less.

To form a conductive polymer thin film made of polyaniline as described above on an insulating substrate, first, a conductive oxidized polymer of aniline doped with protonic acid is prepared, and then this is dedoped. Then, this organic solvent-soluble polyaniline is made into a solution, which is cast or coated onto a substrate, dried to form a thin film, and finally, this thin film is doped with protonic acid. .

First, the conductive oxidized polymer of aniline doped with the protonic acid is prepared by adding aniline to the aniline in a solvent in the presence of a protonic acid having an acid dissociation constant pKa value of 3.0 or less, preferably at a temperature of 5° C. or less. While maintaining the temperature below 0℃,
An aqueous solution of an oxidizing agent whose standard electrode potential, defined as the electromotive force in a reduction half-cell reaction based on a standard hydrogen electrode, is 0.6 V or more is added per mole of aniline to 1 mol of the oxidizing agent.
Oxidative polymerization of aniline by gradually adding 2 equivalents or more, preferably 2 to 2.5 equivalents, defined as the amount of mole divided by the number of electrons required to reduce one molecule of oxidizing agent. can be obtained by

Next, by dedoping the oxidized aniline polymer doped with a protonic acid with a basic substance, an organic solvent-soluble polyaniline can be obtained.

In the above oxidative polymerization of aniline, the oxidizing agent is
Manganese dioxide, ammonium peroxonisulfate, hydrogen peroxide, ferric salts, iodates, and the like are particularly preferably used. Among these, for example, ammonium peroxonisulfate and hydrogen peroxide both have 1
Since two electrons are involved per molecule, amounts in the range 1 to 1.25 moles per mole of aniline are usually used.

In particular, the protonic acid used in the oxidative polymerization of aniline has an acid dissociation constant pKa value of 3.0 or less.
Examples include, but are not limited to, hydrochloric acid, sulfuric acid, nitric acid,
Perchloric acid, fluoroboric acid,.

W such as phosphoric hydrofluoric acid, hydrofluoric acid, hydroiodic acid, etc.
aS, aromatic sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid, alkanesulfonic acids such as methanesulfonic acid and ethanesulfonic acid, phenols such as picric acid, aromatic carboxylic acids such as m-nitrobenzoic acid, Examples include aliphatic carboxylic acids such as dichloroacetic acid and malonic acid.

Polymeric acids can also be used. Examples of such polymer acids include polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallylsulfonic acid, polyvinyl sulfuric acid, and the like.

The amount of protic acid used depends on the reaction mode of the oxidizing agent used. For example, in the case of manganese dioxide, the oxidation reaction is expressed as Mn01+48"+2e-→Mn"+2HgO, so the amount of protic acid used is at least four times the molar amount of the manganese dioxide used. It is necessary to use a protic acid that can supply a large amount of protons. Also, in the case of hydrogen peroxide, the oxidation reaction is HzO=+2H"+2e--+ znz.

Therefore, it is necessary to use a protic acid that can supply at least twice the molar amount of protons as the amount of hydrogen peroxide used. On the other hand, in the case of ammonium belloxonisulfate,
Since the oxidation reaction is represented by StO,"-+2e--2504,"-, there is no need to use a protonic acid. However, even when ammonium belloxonisulfate is used as the oxidizing agent, it is preferable to use a protonic acid in an equimolar amount to the oxidizing agent.

As a solvent for oxidative polymerization of aniline, aniline,
A substance that dissolves the protonic acid and the oxidizing agent and is not oxidized by the oxidizing agent is used.

Water is most preferably used, but if necessary, alcohols such as methanol and ethanol, nitriles such as acetonitrile, N-methyl-2-pyrrolidone,
Polar solvents such as dimethyl sulfoxide, ethers such as tetrahydrofuran, and organic acids such as acetic acid can also be used. Moreover, a mixed solvent of these organic solvents and water can also be used.

In the preparation of the organic solvent soluble aniline oxidized polymer, during the reaction, especially 1. It is important to maintain the temperature of the reaction mixture below 5°C at all times while adding the oxidant solution to the aniline solution. Therefore, the oxidizing agent solution must be added gradually to the aniline so that the temperature of the reaction mixture does not exceed 5°C. When adding an oxidizing agent rapidly, the temperature of the reaction mixture rises even with external cooling.
A low molecular weight polymer is produced, or a solvent-insoluble oxidized polymer is produced even after dedoping, which will be described later.

In particular, in the above reaction, it is preferable to maintain the reaction temperature below 0°C, so that after dedoping,
An organic solvent-soluble polyaniline with a high molecular weight and an intrinsic viscosity [η] of 1 and Odl/g or more measured in N-methyl-2-pyrrolidone at 30° C. (the same applies hereinafter) can be obtained.

In this way, a polyaniline doped with the protic acid used can be obtained. In a doped state,
Since this polyaniline forms a salt with a protonic acid, it does not dissolve in an organic solvent as described below. It is well known that salts of high molecular weight amines are generally poorly soluble in organic solvents.

However, by dedoping this organic solvent-insoluble polyaniline, organic solvent-soluble polyaniline can be obtained.

This dedoping of polyaniline doped with protonic acid is a kind of neutralization reaction, so if it is a basic substance that can neutralize the protonic acid as a dopant,
Although not particularly limited, metal hydroxides such as aqueous ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, and calcium hydroxide are preferably used. For dedoping, a basic substance may be added directly to the reaction mixture after the above-mentioned oxidative polymerization of aniline, or the polymer may be isolated and then treated with a basic substance.

Doped polyaniline obtained by oxidative polymerization of aniline usually has a conductivity of 10-'S/am or higher and has a black edge color, but after dedoping, it has a purple or purplish copper color. be. This discoloration is due to the conversion of the amine nitrogen in the salt structure into free amine in the polymer. The conductivity is typically on the order of 10-''S/am.

The dedoped polyaniline thus obtained has a high molecular weight and is soluble in various organic solvents. Examples of such organic solvents include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, sulfolane, and the like. I can do it. Although the solubility depends on the average molecular weight of the polymer and the solvent, 0.5 to 100% of the polymer is dissolved, and a solution having a concentration of 1 to 30% by weight can be obtained. In particular, polyaniline in this undoped state exhibits high solubility in N-methyl-2-pyrrolidone, and usually has a
% can be dissolved and a 3-30% by weight solution can be obtained.

However, tetrahydrofuran, 80% acetic acid aqueous solution, 60%
% formic acid aqueous solution, acetonitrile, etc.

Therefore, if such organic solvent-soluble polyaniline is dissolved in an organic solvent and cast, a self-supporting, flexible and strong film can be obtained, and if it is cast or coated on a substrate, a base material can be obtained. A strong and flexible thin film can be formed on the material.

In order to obtain a strong film or thin film, organic solvent-soluble polyaniline must have an intrinsic viscosity [η] of 0.40 dl/g or more when measured at 30°C in N-methylpyrrolidone. It is desirable to use one.

The soluble polyaniline was determined from elemental analysis, infrared absorption spectrum, ESR spectrum, laser/Raman spectrum, thermogravimetric analysis, solubility in solvents, and visible to near infrared absorption spectrum (where m and n are each a repeating unit). It shows the mole fraction of the quinone diimine structural unit and the phenylene diamine structural unit in the quinone diimine structural unit and has Q<m<l, Q<n<l, m+nwl) as the main repeating unit.

Here, we will explain the characteristics of organic solvent-soluble polyaniline obtained from laser-Raman spectroscopy while comparing it with conventionally known so-called polyaniline.

Generally, there is vibrational spectroscopy as a means of obtaining information regarding vibrations between atoms constituting a substance, and this includes infrared spectroscopy and Raman spectroscopy. Infrared spectroscopy is active on vibrational modes that result in a change in dipole moment, and Raman spectroscopy is active on vibrational modes that result in a change in polarizability. Therefore,
The two have a complementary relationship; - for boat fishing, the vibration mode that is strong in infrared spectroscopy is weak in Raman spectroscopy;
On the other hand, vibrational modes that appear strongly in Raman spectroscopy are weak in infrared spectroscopy.

Infrared absorption spectra are obtained by detecting energy absorption between vibrational levels, and Raman spectra are
Scattered light (Raman scattering) that occurs when molecules fall to a higher vibrational level of the ground state after being excited by light irradiation.
obtained by detecting. At this time, the vibrational energy level can be determined from the energy difference between the scattered light and the irradiated light.

Usually, a Raman spectrum is obtained by visible light excitation from an argon laser or the like. It is known that when a sample has an absorption band in the visible region, when the irradiated laser beam and the wavelength of the absorption band are matched, a very strong Mann line can be obtained.

This phenomenon is called the resonance Raman effect, and according to this, a Raman line that is 10' to 10' times stronger than a normal Raman line can be obtained. According to such a resonance Raman effect, information about the chemical structure portion excited by the wavelength of the irradiated laser light can be obtained in a more emphasized manner. Therefore, by measuring the Raman spectrum while changing the wavelength of the irradiated laser light, the chemical structure of the sample can be analyzed more accurately. Such features are features of Raman spectroscopy that are not found in infrared spectroscopy.

Figure 1 shows organic solvent soluble N-methyl-2-
The intrinsic viscosity [η] measured at 30°C in pyrrolidone is 1.
An excitation wavelength of 45.2 dl/g was obtained for a disk-shaped sample of dedoped polyaniline powder with an excitation wavelength of 45.2 dl/g.
This is a laser Raman spectrum obtained by irradiation at 7.9 nm. Attribution of Raman lines is as follows. 162
2 and 1591cm-' are the skeletal stretching vibrations of para-substituted benzene, 1489 and 1479cae-' are the stretching vibrations of C=C and C=H in the quinone diimine structure, 1220c
m-' is a mixture of C-N stretching vibration and C-C stretching vibration, 11
85 and 1165 cm-' are in-plane bending vibrations of C-H.

Figure 2 shows Y, Furukawa al., 5yn.
th, Met, + Dan.

189, (1986), which was obtained by irradiating polyaniline in a dedoped state with an excitation wavelength of 457.9 nm. This polyaniline was obtained by electrolytic oxidative polymerization of aniline on a platinum electrode.

As shown in FIG. 1, in the solvent-soluble dedoped polyaniline used in the present invention, among the skeletal vibrations of para-substituted benzene, the Raman line intensity of the skeletal stretching vibration that occurs at a wave number higher than 1600 cm-' 1a and 1600c
The ratio 1a/Ib to the Raman line intensity rh occurring at a lower wave number than m-' is 1.0 or more. On the other hand, all conventionally known polyanilines including the polyaniline shown in FIG. 2, including those produced by chemical oxidative polymerization, have the ratio 1a/Ib smaller than 1.0.

The Raman lines at 1622 and 1591 cm-' are both based on skeletal stretching vibrations of para-substituted benzene. Polyaniline in a reduced state does not have a quinone diimine structure, so Raman lines are generated only at 1621c+i-', but polyaniline in an undoped state, which has a quinone diimine structure, produces Raman lines at 1622 and l, as described above.
A Raman line is located at 591cr'. These Raman lines exhibit excitation wavelength dependence as shown in FIG.

The excitation wavelength was changed from 488.0 nm to 476.5 nm to 4
As the wavelength changes to 57.9 nm, the I
a/Ib changes. That is, 488.0 nm
When , I a / T b is smaller than 1.0, but 4
At 57°9 nm, it is 1.0 or more, which is 488.
Compared to Onm, the I a / I b intensity is reversed. This reversal phenomenon may be explained as follows.

FIG. 4 shows the electronic spectrum of solvent-soluble polyaniline. The peak at 647 nm disappears when polyaniline is reduced, so it appears to be derived from the quinone diimine structure, and the peak at 334 nm, on the other hand, increases in intensity when polyaniline is reduced, indicating the π-π9 transition of para-substituted benzene. It seems to have originated from. FIG. 4 shows the Raman excitation wavelengths described above. Here, for the para-substituted benzene skeleton stretching vibration band, the excitation wavelength is set to 4
When changing from 88.0 amount m to 457.9 amount m to the short wavelength side, compared to the band of 1591 cm-', 162 cm-'
It is considered that the resonance conditions of the resonance Raman effect of the 2cn+-' band become more favorable, and the above-mentioned change in relative intensity occurs.

Next, in the spectra shown in Figures 1 and 2, 15
The reason why the relative intensities of the Raman lines at 91 cm-' and 1622 cm-' are different despite having the same excitation wavelength (457,9 m) may be explained as follows. That is, N as a model compound of phenylenediamine structure,
N'-diphenyl-p-phenylenediamine is 161
N,N'-diphenyl-p-benzoquinone diimine, which has a Raman line only at 7 cm-' and is a model compound of the quinone diimine structure, has Raman lines at 1568 co+-' and 1621
Since it has a Raman line in co+-', as shown in Ta) below, the para-substituted benzene ring that is non-conjugated with the quinone diimine structure has an increased intensity upon excitation with short wavelength light162
It is estimated that the para-substituted benzene ring having a Raman line of 2 cm-' and conjugated with the quinone diimine structure has Raman lines of 1591 cm-' and 1622 cm-', as shown in (b) below.

N, N'-diphenyl-monophenylenediamine quinone diimine structure ■ ■ (a) (b) 622 cm 591 cm 1622 cab-' From the results of elemental analysis, the number of quinone diimines and phenylene in undoped solvent-soluble polyaniline Since the number of diamines is considered to be approximately equal, the structural chain of such dedoped solvent-soluble polyaniline is determined from the connection mode of the quinone diimine structure and the phenylene diamine structure (as shown in C1, the quinone diimine structure and the phenylene diamine structure alternate). It is classified into two types: copolymer chain and block copolymer chain of quinone diimine structure and phenylene diamine structure as shown in Tdl. In the figure, the para-substituted benzene ring indicated by the arrow is Indicates a conjugated benzene ring, in the above-mentioned alternating copolymer chain, for example, two per octameric chain unit, and in a block copolymer chain, for example, three per octameric chain unit. If the chain unit is long, the difference in the number of quinone diimine and non-conjugated benzene rings in both becomes even larger.
It can be said that this is caused by the difference in relative intensity between the Raman lines m- and 1622 cm+-'.

Since the IalIb ratio in the laser Raman spectrum is 1.0 or more, solvent-soluble polyaniline contains many quinone diimine structures and non-conjugated benzene rings, and thus has the block copolymer-like chain. It seems that.

The solubility of polyaniline in organic solvents is rationally explained by the presence of such block copolymer-like chains.

Generally, the imine nitrogen (-N
=) is known to form a hydrogen bond with the nearby secondary amino group nitrogen (-NH-) (Macromo
lecules+ 2L 1297 (1988)), the hydrogen bonds between the nitrogens of the secondary amino groups are not strong.

Therefore, when polyaniline has the above-mentioned alternating copolymer chains, it forms a strong network of hydrogen bonds as shown in fl. The insolubility appears to be due to the formation of a strong network of such hydrogen bonds.In contrast, as in dedoped solvent-soluble polyaniline, the polymer chains form the block copolymer chains. In the case of If the block chains have exactly the same length, Although it will form a hydrogen bond network as described above, the probability of having such a structure is extremely small, so
Normally it can be ignored.

\ / Furthermore, such interchain interactions can also be explained from the C-H in-plane bending vibration in the laser Raman spectrum.

The C- of polyaniline in the dedoped state shown in FIG.
The Raman line at 1162cm+-', which is attributed to the H in-plane bending vibration, becomes 1181cm- when polyaniline is reduced and all the nitrogen nitrogens are converted to secondary amino nitrogens.
' shift to a higher wavenumber.

As described above, in a dedoped state, solvent-soluble polyaniline has two Raman lines, 1165 and 1185ca+-', which are attributed to C-H in-plane bending vibration. This Raman line at 1185 cm-' is not observed in conventionally known dedoped polyaniline, and is close to 1181c1', which is attributed to the C-H in-plane bending vibration in the reduced state. It shows.

From these points, it is considered that the solvent-soluble polyaniline has a block copolymer-like chain in a dedoped state and has an atmosphere of a reduced structure.

From this, it is likely that the organic solvent-soluble polyaniline used in the present invention has high solubility in organic solvents despite its high molecular weight. It is a new polymer with a different structural chain.

In this way, the oxidized polymer of aniline has a quinone diimine structural unit and a quinone diimine structural unit in a block copolymer chain as described above as repeating units, so it cannot be doped with protonic acid. In this state, it is explained that it has conductivity only through acid-base reactions without any redox reactions. This conduction mechanism was proposed by A, G, MacDiarmid et al.

MacDiarn+id et al., J. Ch.
em, Soc,, CheII! .

By doping with a protic acid, the quinone cation radical structure is protonated, as shown below, and this forms a semiquinone cation radical structure, which has electrical conductivity.

Such a state is called a polaron state.

■ HX (protonic acid) ↓ Intramolecular redox reaction (semiquinone cation radical (Polaron)) As mentioned above, polyaniline, which is solvent-soluble in an undoped state, can be dissolved in an organic solvent and cast onto a substrate. For example, a thin film can be formed, and conductivity can be easily imparted by doping such a thin film with protonic acid. Here, as the protonic acid, those mentioned above can be used.

The conductivity of the conductive thin film obtained by doping depends on the pKa value of the protonic acid used. In the present invention, protonic acids with a pKa value of 4.8 or less are effective,
When using a protonic acid having a pKa value of 1 to 4.8, the smaller the pKa value, that is, the stronger the acidity, the higher the electrical conductivity of the obtained thin film.

However, when the pKa value is less than 1, the conductivity of the thin film no longer changes much and is almost constant.

However, of course, a protonic acid having a pKa value of 1 or less may be used if necessary.

The conductivity of the thin film thus obtained by protonic acid doping is usually greater than 10-'S/4, often greater than 10-'S/am.

This conductive thin film is strong and does not break easily even when the base material is bent. However, like the conductive aniline oxidized polymer prepared in the presence of protic acid, this thin film is doped with protic acid and therefore does not dissolve in the organic solvent mentioned above for the reasons mentioned above.

In the present invention, by using polyvinylsulfonic acid as the protonic acid, it is possible to obtain a conductive thin film in which dedoping is particularly difficult to occur.

Generally, polyaniline obtained by oxidative polymerization is doped with a protonic acid used during polymerization and has electrical conductivity. However, it is known that such conductive polyaniline releases protonic acid, which is a dopant, in a weakly acidic, neutral, or alkaline aqueous solution or a basic organic solvent, and its conductivity decreases significantly. ing.

Furthermore, the protonic acids commonly used as dopants are low molecular acids such as hydrochloric acid, sulfuric acid, and perchloric acid. Acid easily diffuses,
It may also corrode the surrounding metal parts in which it is used.

However, the conductive polyaniline thin film having polyvinyl sulfonic acid as a dopant is not only polyaniline doped with the above-mentioned low-molecular-weight acids, but also compared to polyaniline doped with polymer acids such as polystyrene sulfonic acid, polyvinyl sulfonic acid, and polyvinyl sulfuric acid. Also, in an aqueous solution with a pH of 2.5 or higher, especially around neutrality, the decrease in electrical conductivity is extremely small.

The reason why the electrical conductivity of polyaniline doped with polyvinyl sulfonic acid is so small is not necessarily clear, but it is due to the polymer effect due to polyvinyl sulfonic acid being a polymeric acid with polyvalent charges. This is thought to be due to the molecular structure effect in which polyvinylsulfonic acid strongly interacts with polyaniline at the molecular level.

To dope a dedoped polyaniline thin film with polyvinylsulfonic acid, the polyaniline thin film is usually immersed in an aqueous polyvinylsulfonic acid solution having a pH of 2 or less. The time required for doping depends on the thickness of the polyaniline thin film used and the pH of the polyvinylsulfonic acid aqueous solution, but usually ranges from several tens of seconds to several days. In order to shorten the doping time, it is preferable to use an aqueous solution with a pH of 1 or less. Furthermore, in general, if polyvinyl sulfonic acid with a low degree of polymerization is used, it can be doped quickly, whereas if polyvinyl sulfonic acid with a high degree of polymerization is used, -N, conductive polyaniline, which is difficult to dedope, can be doped. A thin film can be obtained.

In this way, a polyaniline thin film containing polyvinylsulfonic acid as a dopant is difficult to release the dopant in a weakly acidic, neutral, or alkaline aqueous solution or in a basic organic solvent, so it is difficult to form a thin film on an insulating substrate. During the various processes of oxidation, cleaning with water or organic solvents can
Not only can a conductive thin film be advantageously formed without any change in conductivity, but also its excellent chargeability can be maintained regardless of changes in ambient environmental conditions such as humidity and moisture.

Further, for example, by doping a polyaniline thin film with polyvinylsulfonic acid and washing it thoroughly with water, it is possible to obtain a conductive thin film that does not contain other protonic acids, such as the above-mentioned low molecular acids, as a dopant. Therefore, in such a conductive thin film, there is no risk of corrosion of surrounding metal parts by low molecular acids that may be partially mixed into conductive polyaniline as a dopant.

According to the present invention, a solution of polyaniline soluble in an organic solvent is cast or coated on an insulating substrate, dried to form a thin film, and then doped with protonic acid to form a conductive layer on the substrate. A thin film can be easily formed.

In the present invention, the insulating base material is not particularly limited, and includes, for example, films made of various resins such as polyester, polypropylene, and polyethylene, paper, and porous materials such as woven and nonwoven fabrics made of various fibers. Examples include composite materials in which a thermoplastic resin such as polyethylene or polypropylene is laminated onto a sheet.

In particular, according to the present invention, since the process of applying solvent-soluble polyaniline to the base material and the doping process can be performed separately, it is possible to easily form a conductive thin film on the base material.

Furthermore, according to the present invention, since the solvent-soluble polyaniline can be formed into a film by casting or coating, the thickness of the thin film on the substrate can be adjusted as desired.

For example, according to the present invention, the film thickness o, oi~20
A thin film of 0 μm can be formed. As described above, if such a thin film is doped with a protonic acid having a pKa value of 4.8 or less, a thin film having an electrical conductivity of 10-6 to 30S101 can be formed on an insulating substrate.

Further, for example, a thin film having a thickness of 0.01 to 0.5 μm can be continuously formed on a transparent base film such as polyethylene terephthalate and wound up. Furthermore, by adjusting the thickness of the thin film, the surface resistance can be controlled in various ways. In particular, the thickness of the thin film is 0.01 to 0.5
By setting the conductive thin film to about .mu.m, the film having the conductive thin film has a visible light transmittance of 80% or more and a surface resistance of about 10@4 to 10" .OMEGA./hole.

In the present invention, the adhesive used in the adhesive tape is as follows:
Generally known acrylic adhesives and rubber adhesives are used. Furthermore, as the release agent for adhesive tapes and release papers, conventionally known silicone-based and long-chain alkyl-based release agents are used.

Usually, the mold release agent is coated in a thin layer, so its surface resistance is low and does not impair antistatic performance.

The release sheet or adhesive tape obtained as described above usually has a surface resistance in the range of 10' to 10'' Ω and is not affected by humidity. It also has excellent adhesion with adhesives.

The drawings show examples of release sheets and adhesive tapes according to the present invention.

FIG. 5 shows an example of a single-sided release sheet, in which a conductive polymer layer 2 made of polyaniline is formed on one side of a base material 1, and a release agent layer 3 is further formed thereon. . FIG. 6 shows an embodiment of a double-sided release sheet, in which conductive polymer layers 2 and 2'' made of polyaniline are placed on both sides of a base material l.
is formed, and mold release agents N3 and 3' are further formed thereon.

FIG. 7 shows an example of a single-sided adhesive tape, in which a conductive polymer N2 made of polyaniline is formed on one side of a base material 1, and a release agent layer 3 is further formed thereon. On the other hand, an adhesive layer 4 is formed on the other surface of the base material. In FIG. 8, a laminated paper 7 in which a polyethylene layer 6 is laminated on a kraft paper 5 is used as a base material, a conductive polymer layer 2 is formed on the polyethylene laminate side, and a mold release agent layer 3 is further formed on the polyethylene laminate side. On the other hand, an adhesive layer 4 is formed on the other side of the base material. FIG. 9 shows another embodiment, in which conductive polymer layers 2 and 2° are formed on both sides of the base material l, and a mold release agent layer 3 is formed on one conductive polymer N2. An adhesive layer 4 is formed on the other conductive polymer layer 2'.

As described above, according to the release sheet or adhesive tape of the present invention, a thin film of a conductive polymer made of polyaniline is laminated on a base material, and a release agent layer or an adhesive is applied on top of the thin film of a conductive polymer made of polyaniline. Even with the agent layer, the conductivity of the surface is maintained, and the adhesion between the conductive polymer thin film layer and the release agent layer or adhesive layer is excellent, and furthermore, the conductivity of the thin film is Since it is based on conduction, it is stable regardless of changes in ambient environmental conditions such as humidity and moisture, and thus, according to the present invention, it is possible to obtain a release sheet or adhesive tape that stably has high antistatic performance. As mentioned above, various inconveniences associated with its use are eliminated.

Furthermore, unlike many conventionally known conductive polymers, the conductive polymer made of polyaniline used in the present invention is obtained by forming a thin film of organic solvent-soluble polyaniline and doping it. According to the method, a transparent conductive thin film can be formed as a continuous layer on a base material, and a front sheet or adhesive tape can be obtained that has antistatic properties uniformly over the entire surface.

Therefore, the adhesive tape according to the present invention can be suitably used, for example, as a packaging tape, particularly as a tape for packaging electronic materials.

The present invention will be explained below with reference to examples to show the production of organic solvent-soluble polyaniline used in the present invention, but the present invention is not limited by these Examples in any way.

Reference Example 1 (Production of doped conductive organic polymer by oxidative polymerization of aniline) 6000 g of distilled water, 360 ml of 36% hydrochloric acid, and 400 g of aniline ( 4,295 moles)
were added in this order to dissolve the aniline. Separately,
1493g of distilled water in a beaker while cooling with ice water
434 g (4,295 mol) of 97% concentrated sulfuric acid was added and mixed to prepare a sulfuric acid aqueous solution. This sulfuric acid aqueous solution was added to the above-mentioned separable flask, and the entire flask was cooled to -4°C in a low temperature constant temperature bath.

Next, 980 g (4,295 mol) of ammonium beloxonisulfate was added to 2293 g of distilled water in a beaker.
An oxidizing agent aqueous solution was prepared by dissolving it.

While cooling the entire flask in a low temperature ↑ temperature bath and maintaining the temperature of the reaction mixture below -3°C, add the above ammonium beroxon disulfate to the acidic aqueous solution of aniline salt from the straight pipe adapter using a tubing pump while stirring. An aqueous solution was gradually added dropwise at a rate of 1 ml/l. Initially, the colorless and transparent solution turned from greenish-blue to a black-rimmed color as the polymerization progressed, and then a black-rimmed powder was precipitated.

An increase in temperature is observed in the reaction mixture during this powder precipitation, but in this case as well, in order to obtain a high molecular weight polymer according to the present invention, the temperature in the reaction system must be kept below 0°C, preferably below -3°C. It is important to keep it to a minimum. After the powder is precipitated, the dropwise rate of the aqueous solution of beroxonisulfate may be increased, for example, to about 8 ml/min. However, even in this case, while monitoring the temperature of the reaction mixture,
It is necessary to adjust the drop rate to keep the temperature below -3°C. Thus, after completing the dropwise addition of the aqueous solution of ammonium beroxonisulfate, which took 7 hours,
Stirring was continued for an additional hour at a temperature below -3°C.

The obtained polymer powder was filtered, washed with water and acetone,
It was vacuum dried at room temperature to obtain 430 g of a black-rimmed polymer powder. This was pressure-molded into a disk with a diameter of 13n and a thickness of 700 μm, and its electrical conductivity was measured by the van der Boe method and found to be 14 S/cta.

(Dedoping of conductive organic polymer with ammonia) 350 g of the above doped conductive organic polymer powder was added to 2N ammonia water 41, and stirred for 5 hours at a rotation speed of 500 Orpm in an auto-water mixer. . The mixture changed from a black border color to a blue-purple color.

The powder was filtered out using a Buchner funnel, washed repeatedly with distilled water while stirring in a beaker until the filtrate became neutral, and then washed with acetone until the filtrate became colorless. Thereafter, the powder was vacuum dried at room temperature for 10 hours to obtain 280 g of a dark brown undoped polymer powder.

This polymer is soluble in N-methyl-2-pyrrolidone, and the solubility is 8 g (7.4%) per 100 g of the same solvent.
)Met. Further, the intrinsic viscosity [η] measured at 30° C. using this as a solvent was 1.23.

This polymer had a solubility of less than 1% in dimethyl sulfoxide and dimethyl formamide.

Tetrahydrofuran, pyridine, 80% acetic acid aqueous solution, 6
It was not substantially dissolved in 0% formic acid aqueous solution and acetonitrile.

FIG. 1 shows a laser Raman spectrum obtained by irradiating a disk-shaped sample of this undoped polyaniline powder with an excitation wavelength of 457.degree. 9 nm.

For comparison, Y, Fujiwara et al, +
5ynth, Met,, 16.189 (198
Regarding the undoped polyaniline shown in 6),
The laser beam obtained by irradiation with an excitation wavelength of 457.9 nm
The Raman spectrum is shown in Figure 2. This polyaniline was obtained by electrolytic oxidative polymerization of aniline on a platinum electrode.

In addition, by changing the wavelength of the laser excitation light,
Figure 3 shows the results of Raman spectra measured in a range of 1700 cm-'. The excitation wavelength was set to 488.0n.
As the wavelength changes from m to 476.5 nm to 457°9 nm, Ia/rb changes, and 457°
．． At 9nm, it is 1.0 or more, 488.0n
It is shown that the Ia/Ib intensity is reversed compared to when m.

Further, FIG. 4 shows the electronic spectrum.

Next, regarding the organic solvent soluble polyaniline, N-
Using a GPC column for methyl-2-pyrrolidone, G
PC measurement was performed. Three types of columns for N-methyl-2-pyrrolidone were used in combination. In addition, the eluent contained 0. N- of lithium bromide of O1 mol/1iJ1 degree
A methyl-2-pyrrolidone solution was used. GP in Figure 1O
The results of C measurement are shown.

From this result, the organic solvent-soluble polyaniline has a number average molecular weight of 23,000 and a weight average molecular weight of 160,000.
(All values are based on polystyrene standards).

Similarly, organic solvent-soluble polyanilines having different intrinsic viscosities [η] measured in N-methyl-2-pyrrolidone at 30° C. were obtained by varying the reaction conditions. Regarding these,
Table 1 shows the intrinsic viscosity [η] and the number average molecular weight and weight average molecular weight determined by GPC.

Table Reference Example 2 (Preparation of self-supporting film using soluble aniline oxide polymer) Add 5 g of the dedoped aniline oxide polymer powder obtained in Reference Example 1 little by little to 95 g of N-methyl-2-pyrrolidone. Dissolution at room temperature yielded a black-blue solution. When this solution was vacuum filtered using a 03 glass filter, extremely small amounts of insoluble matter remained on the filter. This filter was washed with acetone, and after drying the remaining insoluble matter, the weight was measured and found to be 75 cm. Therefore, 98.5% of the polymer is dissolved, and the insoluble matter is 1.5%.
%Met.

The polymer solution thus obtained was cast onto a glass plate and squeezed with a glass rod, followed by continuous evaporation of N-methyl-2-pyrrolidone in a hot air circulating drying layer.

After this, by immersing the glass plate in cold water, the polymer film will peel off naturally from the glass plate, thus
A polymer film with a thickness of 40 μm was obtained.

After washing this film with acetone, it was air-dried at room temperature to obtain a film with copper-colored metallic luster.

Films differ in strength and solubility depending on their drying temperature. When the drying temperature is 100° C. or less, the resulting film dissolves in N-methyl-2-pyrrolidone to a small extent and has relatively low strength. However, the film obtained by heating at a temperature of 130° C. or higher is very tough and does not dissolve in N-methyl-2-pyrrolidone or other organic solvents. It also does not dissolve in concentrated sulfuric acid. Thus, it appears that when heated at high temperatures, the polymer molecules crosslink with each other in the process and become insoluble.

All of the dedoped films obtained in this way had electrical conductivities in the order of LO-''S/el1.

Further, the film did not break even after being bent 100 times, and its tensile strength was 850 kg/c+J.

Reference Example 3 (Doping of self-supporting film with protonic acid) In Reference Example 2, the self-supporting film obtained by heating and drying at 160°C for 2 hours was placed in aqueous solutions of IN sulfuric acid, perchloric acid, and hydrochloric acid at room temperature for 66 hours. After being immersed for 7 hours, it was washed with acetone and air-dried to obtain conductive films.

All of the films exhibited a deep blue color, and the electrical conductivities were 9S/e1m, 13S/e11, and 6S/cm, respectively. Further, the tensile strength of the film doped with perchloric acid was 520 kg/cd.

Reference Example 4 (Spectrum and structure of soluble polymer and insoluble film-formed polymer both in dedoped state) Spectrum and structure of soluble polymer powder obtained in Reference Example 1 and insoluble polymer film obtained in Reference Example 2 FT-IR spectra obtained by the KBrBr method are shown in FIG. 11 and FIG. 12, respectively. In the spectrum of the insoluble polymer film obtained in Reference Example 2, 16
Although some absorption at 60 cm-' is observed, the two spectra are almost the same, so although the polymer becomes solvent-insolubilized by crosslinking when the solvent is heated and dried after casting the solvent-soluble polymer, it has a large chemical structure. It is recognized that no change has occurred.

Next, the results of elemental analysis of the soluble polymer and insoluble polymer are shown below.

Dandan 1-layer beanmei C,? ? , 19; H, 4,76; N, 14.86
(Total 96.81) Tamagai Enri Kinki C, 78:34; H, 4,99; N, 15.16
(Total 98.49) Based on this elemental analysis, C
The compositional formula of the soluble polymer standardized to 12,OO is C1t
,. . Ha, atNr, qn, and the compositional formula of the insoluble polymer is C+Z. . 119.11N1.99. On the other hand, similarly, the quinonediimine structural unit and phenylenediamine structural unit normalized to CI 2.00 are:
Each is as follows.

Quinonediimine ´Notice standalone C1□) I, NZ Phenylenediamine °6゛C1! HIllNt Therefore, as mentioned above, both the soluble polymer and the solvent-insoluble polymer
It is a polymer having quinonediimine structural units and phenylenediamine structural units as main repeating units.

Reference Example 5 The polymer film obtained in Reference Example 2 was immersed in aqueous or alcoholic solutions of protonic acids having various pKa values, and the possibility of doping was investigated. The electrical conductivity of polymer films obtained by doping with protic acids having various pKa values is shown in Table 2. It is shown that protic acids with pKa values of 4.8 or less are effective for doping polymers.

Reference Example 6 (Manufacture of transparent conductive thin film composite) A 0.5% by weight N-methyl-2-pyrrolidone solution of the solvent-soluble polyaniline powder obtained in Reference Example 1 was prepared, and a thickness of 75 μm was prepared.
It was coated on a polyethylene terephthalate film of 100 mL and dried at 150° C. for 1 hour. The resulting composite film was doped by immersing it in an aqueous IN perchloric acid solution for 3 hours, then washed with acetone, and air-dried. The visible light transmittance of the obtained composite film was 80% or more in the range of 400 to 800 nm.

The composite film was cut into a square, silver paste was applied to two opposing sides, and the surface resistance was measured, and it was found to be 3.5MΩ.
/It was a mouth. Moreover, the electrical conductivity was 0.02 S/cm. As a result of observation using a transmission electron micrograph of a cross section of this composite film, the thickness of the polyaniline film was approximately 0.
It was 1 μm. The half-life of the charged charge was 0.05 seconds.

This composite film can also be used in a vacuum or in an argon-substituted glove box (dew point -37°C, moisture content 18°C).
Even under low humidity (0 ppm), the surface resistance hardly changed.

Example 1 A 0.2% toluene solution of polyvinyl stearyl carbamate (mold release agent) was applied at a rate of 10 g/g onto the composite film prepared in Reference Example 6, and dried to form a mold release surface. did.

Next, an acrylic adhesive was applied to the back surface of the composite film to a thickness of 30 μm to produce an adhesive tape. The surface resistance of the back surface of the tape (release agent surface) was 107 Ω/hole, and the charging potential immediately after the tape was rewound was almost OV.

In addition, a visual adsorption test using ash from an ashtray, flocked pile, etc. was conducted, and the results showed that the antistatic performance of the adhesive tape was good in all cases.

Similarly, double-sided corona discharge treated polypropylene film (
40 μm thick), polyethylene laminated paper, polyethylene laminated cotton cloth, polyethylene laminated polyester nonwoven fabric, etc., are treated with a mold release agent such as a silicone mold release agent or a long-chain alkyl mold release agent, or are further treated with an acrylic adhesive or rubber-based mold release agent. Release paper and adhesive tape were produced by coating and laminating adhesive.

Similar to the above, excellent antistatic performance was confirmed for these as well.

[Brief explanation of drawings]

Figure 1 shows the laser Raman spectrum when organic solvent-soluble polyaniline in a dedoped state used in the production of a release sheet or adhesive tape according to the present invention is excited with light at a wavelength of 457.9 nm. Figure 3 shows the laser Raman spectrum when the more well-known polyaniline is excited with light at a wavelength of 457.9 nm.
Laser Raman spectra when organic solvent-soluble polyaniline is excited with light of various excitation wavelengths as shown in Figure 1. Figure 4 shows a solution of the organic solvent-soluble aniline oxidized polymer in N-methyl-2-pyrrolidone. This is the electronic spectrum of FIG. 5 is a cross-sectional view of a main part showing an embodiment of a single-sided release sheet according to the present invention, FIG. 6 is a cross-sectional view of a main part showing an embodiment of a double-sided release sheet according to the present invention, and FIG. FIG. 8 is a sectional view of a main part showing an embodiment of a single-sided adhesive tape according to the invention, and FIG.
FIG. 3 is a sectional view of a main part showing another embodiment of the adhesive tape according to the present invention. FIG. 10 is a graph showing an example of the molecular weight distribution according to Gpc of the solvent-soluble polyaniline, FIG. 11 is an FT-IR spectrum of the solvent-soluble polyaniline measured by the KBr tablet method, and FIG. 12 is a graph of the polymer of the solvent-soluble polyaniline. K of the solvent-insoluble film obtained by casting
This is an FT-IR spectrum obtained by the BrBr method. DESCRIPTION OF SYMBOLS 1... Base material, 2... Conductive polymer layer made of polyaniline 7, 3 and 3'... Release agent layer, 4... Adhesive layer.

Claims (1)

[Claims] (1) A thin film of a conductive polymer made of polyaniline is formed on at least one surface of the insulating base material, and further,
A release sheet comprising a release agent layer formed thereon. (2) A conductive polymer made of polyaniline has a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. , 0<m<1, 0<n<1, m+n=1) as the main repeating unit, which is soluble in organic solvents in a dedoped state, and N-
Intrinsic viscosity [η] measured at 30°C in methylpyrrolidone
is 0.40 dl/g or more and 457.9 nm
Among the skeletal vibrations of para-substituted benzene in the laser Raman spectrum obtained by excitation with light of wavelength, 16
The ratio Ia/Ib of the Raman line intensity Ia of the skeleton stretching vibration occurring at a wave number higher than 00 cm^-^1 and the Raman line intensity Ib of the skeleton stretching vibration occurring at a wave number lower than 1600 cm^-^1 is 1. 2. The release sheet according to claim 1, wherein an organic solvent-soluble polyaniline having a pKa value of 0 or more is doped with a protonic acid having a pKa value of 4.8 or less. (3) A thin film of a conductive polymer made of polyaniline is formed on at least one surface of the insulating base material, and further,
An adhesive tape characterized by having an adhesive layer formed thereon. (4) A conductive polymer made of polyaniline has a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. , 0<m<1, 0<n<1, m+n=1) as the main repeating unit, which is soluble in organic solvents in a dedoped state, and N-
Intrinsic viscosity [η] measured at 30°C in methylpyrrolidone
is 0.40 dl/g or more and 457.9 nm
Among the skeletal vibrations of para-substituted benzene in the laser Raman spectrum obtained by excitation with light of wavelength, 16
The ratio Ia/Ib of the Raman line intensity Ia of the skeleton stretching vibration occurring at a wave number higher than 00 cm^-^1 and the Raman line intensity Ib of the skeleton stretching vibration occurring at a wave number lower than 1600 cm^-^1 is 1. 4. The adhesive tape according to claim 3, wherein the organic solvent-soluble polyaniline having a pKa value of 0 or more is doped with a protonic acid having a pKa value of 4.8 or less. (5) A thin film of a conductive polymer made of polyaniline is formed on at least one side of the insulating base material, a release agent layer is formed thereon, and an adhesive layer is formed on the opposite side. An adhesive tape characterized by: (6) A conductive polymer composed of polyaniline has a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. , 0<m<1, 0<n<1, m+n=1) as the main repeating unit, which is soluble in organic solvents in a dedoped state, and N-
Intrinsic viscosity [η] measured at 30°C in methylpyrrolidone
is 0.40 dl/g or more and 457.9 nm
Among the skeletal vibrations of para-substituted benzene in the laser Raman spectrum obtained by excitation with light of wavelength, 16
The ratio Ia/Ib of the Raman line intensity Ia of the skeleton stretching vibration occurring at a wave number higher than 00 cm^-^1 and the Raman line intensity Ib of the skeleton stretching vibration occurring at a wave number lower than 1600 cm^-^1 is 1. 6. The adhesive tape according to claim 5, wherein an organic solvent-soluble polyaniline having a pKa value of 0 or more is doped with a protonic acid having a pKa value of 4.8 or less.