JPS5978360A - Conductive base body for recording material - Google Patents

Abstract

PURPOSE:To improve the resistance to water, moisture and solvent and a shelf life by using a soap-free emulsion for a treating agent to be applied on a conductive base body for a recording material used for electrophotographic recording using ZnO as a photosensitive agent. CONSTITUTION:A treating agent consisting essentially of a conductive material, pigment, hydrophobic high polymer emulsion, hydrophilic high polymer emulsion, water resisting agent, etc. is applied on a substrate in a conductive base body for a recording material consisting of ZnO as a photosensitive agent. The hydrophobic high polymer emulsion in this treating agent is the soap-free emulsion obtd. by emulsion polymn. without using any surfactant. The base body applied with such treating agent is improved in the resistance to water and solvent and a long-term shelf life without instability in conductivity occurring in a change in humidity and is decreased in both curling and blocking.

Description

[Detailed Description of the Invention] The present invention relates to electrophotographic recording (excluding offset mastering)
, relates to conductive substrates used in recording materials such as electrostatic recording, and more specifically, it has excellent water resistance and solvent resistance, exhibits stable conductivity even over a wide range of humidity changes, and The present invention relates to an improved conductive substrate having excellent storage stability and the like.

Recording materials such as electrophotographic recording and electrostatic recording are coated with a photoconductive layer formed by dispersing a photoconductive substance such as ZnO, selenium, or CdS in a resin binder or an electrically insulating resin on a support that has been subjected to conductive treatment. A dielectric layer consisting of the following is provided. Generally, these recording layers such as photoconductive layers and dielectric layers are often treated with organic solvents. For this reason, it is necessary for the conductive substrate to exhibit excellent solvent resistance so as not to be attacked by organic solvents.

If this is insufficient, a good image cannot be recorded.

In addition, in wet electrophotographic recording, during development, it is immersed in a developer (toner) in which pigments are dispersed in a hydrocarbon solvent, so a barrier property against this is also required. Toner stains, etc. occur.

In addition, the conductive substrate needs to have high conductivity (generally 1011 Ω·m or less in volume resistivity, more preferably 1010 Ω·m or less), which is stable even under wide changes in humidity conditions.
If this is not satisfied, good images cannot be obtained under various environmental conditions. This is particularly closely related to conductivity, moisture resistance and water resistance of the substrate; in other words, sufficient water resistance is required. In addition, good water resistance is required from the viewpoint of curling properties, blocking properties, two-dimensional stability, and the like. Other properties necessary for the conductive substrate include not inhibiting electrophotographic properties and electrostatic recording properties, and not having any adverse effects upon long-term storage.

Conventional conductive substrates do not necessarily satisfy all of these various performance requirements. That is,
Conventional conductive substrates consist of a support such as paper, a polymer electrolyte,
It can be obtained by directly coating or dipping conductive substances such as inorganic salts, but this alone has extremely poor solvent resistance and water resistance, so in order to improve solvent resistance, polyvinyl alcohol ( Measures such as adding hydrophilic polymers such as PVA), adding hydrophobic polymer emulsions to improve water resistance, and crosslinking with water-resistant agents such as amine resins are used. Also, when carbon flicks, metal powders, conductive metal oxides, etc. are used as conductive substances, basically the same method as above has been used. Improves sex and prevents curling.

It is known that pigments such as clay and calcium carbonate are also used as appropriate for the purpose of improving smoothness.

In this way, a conductive material is coated with several glazes of resin and an inder.
In conventional methods in which pigments and the like are blended, it is extremely difficult to satisfy both solvent resistance and water resistance, which are contradictory properties, to a high degree, no matter what the blending ratio. That is, if the amount of hydrophilic polymer is increased in order to satisfy the solvent resistance.

Water resistance is poor; conversely, if the amount of hydrophobic polymer emulsion is increased to increase water resistance, solvent resistance decreases, even if both are used in appropriate proportions.

Both properties show only halfway performance, and even if you try to improve water resistance with a water-resisting agent, you will have to increase the amount added, extremely high temperature during drying, or dry for a long time. There is a need to heat it.

There were some problems such as gelation of the processing agent, deterioration of the support, and extremely low processing speed, etc., and it was not possible to obtain a product that could be put to practical use.

For this reason, in conventional methods, designs are made to first satisfy solvent resistance, which is the most required property.

The second required property, water resistance, has to be sacrificed, and as a result, image instability due to changes in conductivity in a wide range of humidity conditions, curling, blocking, dimensional stability, etc. are significantly reduced. This resulted in poor performance.

In addition, from the viewpoint of photographic physical properties and electrostatic recording properties, increasing the amount of hydrophobic polymer emulsion results in poor image quality, and even if the amount added is small, images gradually appear when stored for a long time. There was a problem with the change over time, and this was also a major problem that needed to be improved.

In view of this situation, the present inventors conducted repeated research focusing on emulsifiers for emulsions, and finally arrived at the present invention.

That is, one feature of the present invention is the support.

(a) Conductive substance (b) Inorganic or (and) organic pigment (c) Hydrophilic polymer binder (to hydrophobic polymer emulsion) (e) Recording made by applying a treatment agent containing a water resistance agent as an essential component In the conductive substrate for materials, e→hydrophobic polymer emulsion.

In the past, soap-free emulsion was rarely used because the synthesis method was somewhat difficult and there was no need for it, but in recent years, R
It has only gradually come to be used for special purposes such as drilling holes, and of course there is no example of its use as a conductive treatment agent for conductive substrates for recording materials.

The first feature of using a soap-free emulsion is that it is different from a conventional emulsion using a surfactant.
The water resistance of the emulsion is significantly improved. This is because: 1. Due to the presence of surfactants in ordinary emulsion polymerization emulsions, low-molecular hydrophilic substances are always freely present in the dried film and dissolve in water, resulting in poor water resistance.

In the case of a soap-free emulsion that does not contain this surfactant, nothing is eluted by water, and the emulsion itself has high water resistance, so even when using a conductive treatment agent, adding a small amount to the emulsion is sufficient. It is thought that hydrophobicity is obtained, that is, water resistance is improved.

As a result, 2. The instability of conductivity and recording due to changes in humidity has been resolved, and stable recording can now be made even under a wide range of environmental conditions.

In addition, the occurrence of curls is significantly reduced, and even when the humidity changes from low humidity to high humidity and from high humidity to low humidity, N and N are added to the curls.
1& The problems with transportability were completely resolved. In addition, the blocking characteristics have been significantly improved and l'J! Problems with construction and transportability were resolved.

By using a soap-free emulsion in this way, water resistance is greatly improved.

In fact, it was discovered that not only water resistance but also solvent resistance was synergistically improved, which was a completely unexpected effect.

The cause of this is not clear, but it is a phenomenon peculiar to surfactants. 1 There is a freely movable surfactant on the surface of emulsion particles obtained by ordinary emulsion polymerization, and it naturally has a large affinity for organic solvents. However, according to the method of the present invention that uses an emulsion that does not use a surfactant, the conductive treatment agent once formed has a low resistance to the solvent. It is presumed that the solvent resistance is improved because there is no surfactant that dissolves into organic solvents.

This allows the amount of hydrophilic polymer to be reduced as increasing the proportion of soap-free emulsion does not reduce the solvent resistance, which in turn reduces the viscosity of the treatment agent and allows the use of fairly high concentrations of treatment agent. There are manufacturing advantages such as being able to reduce the drying speed.

In addition, as mentioned above, when a normal emulsion polymerization emulsion is used, it has a negative effect on electrophotographic properties and electrostatic recording properties, and good images may not be obtained or may deteriorate further over time. Although there is a problem, it has been found that this problem can be completely solved by using the method of the present invention.

In other words, ``The reason that these recording characteristics were adversely affected was that the surfactant used in the emulsion polymerization emulsion elutes or gradually migrates into the photoconductive layer and dielectric layer, causing sensitization in the photoconductive layer. This is because the surfactant reacts with the dye and destroys the electrical insulation properties of the 9g electric layer, and these eight problems were solved by removing these surfactants that have an adverse effect.

As described above, the effects of the present invention are wide-ranging.

In summary, it has a high degree of water and solvent resistance.

Shows stable conductivity even under wide range of humidity changes.

No adverse effect on electrophotographic properties or electrostatic recording properties.

It also provides a conductive substrate that has excellent storage stability over time.

The following two inventions will be explained in more detail.

The conductive substances applicable to the present invention include the following nine substances.

■Inorganic salts: hydrochlorides, nitrates, sulfates, carbonates.

Phosphate etc.

■Organic hygroscopic substances: Glycerin, ethylene glycol, nlubitol, cyanated sludge Cationic: High molecular compounds having a quaternary ammonium base, sulfonium base, or phosphonium base in the main chain or side chain.

fL Polyvinylbenzyltrimethylammonium chloride 7 = Ionicity... A polymer compound having a carboxylic acid group, a sulfonic acid group, or a phosphonate group in its side chain.

Examples, sodium folystyrene sulfonate, sodium polyacrylate, amphoteric polymer compounds that share a cationic functional group and an anionic functional group.

■Metal fine powder...Au r Ag + Cu +
AI) Nt + Cr.

Fe, etc. ■ Conductive metal oxide: A metal oxide such as ZnO doped with In, Cd, etc. on its surface. ZnO, etc., heat treated in C,0,,802,NH,gas. Solid solutions such as 5n02°5b02. A reduced form of TiO2.

TiO2 5n02!9. ．． Treated with 5bOt.

Carbon black: powder, carbon fiber, etc. In the present invention, these conductive materials can be used alone or in combination.

The soap-free emulsion used in the present invention is as follows:
Glazes are broadly categorized into those manufactured using synthetic methods.

(1) Persulfate (Kt 5tOa, Na2
8,08° (NH4) 28208, etc.) and performing the polymerization while stirring or vibrating at a higher speed than in normal emulsion polymerization. (Stabilization by -OSO3- ions) (2) Ionic azobis type catalyst 1 as an initiator, for example.

Sodium azobisisobutyronitrile sulfonate.

Using azobisisobutyramidine hydrochloride etc.

Polymerization is carried out while performing high-speed stirring and high-speed vibration in the same manner as in (1).

(8) Copolymerize the main monomer with a water-soluble comonomer.

For example, styrene monomer, 4 acrylic acid monomers are used as comonomers, and 1 is polymerized while stirring or vibrating at a higher speed than in normal emulsion polymerization.

(4) Perform emulsion polymerization using a polymeric protective colloid as an emulsifier.

For example, a styrene-maleic anhydride copolymer is used as a protective colloid, and methyl acrylate monomer is polymerized with stirring or vibration at a higher speed than in normal emulsion polymerization.

Among these, (l) and φ) are soap-free emulsions in the purest sense and can be said to be the most suitable for the present invention, but (3) and (4) are also sufficiently effective in that they do not use a surfactant. are recognized and are naturally included in the present invention.

The type of resin used in the soap-free emulsion is not particularly limited, and includes styrene.

Vinyl acetate, acrylic ester, methacrylic ester, acrylonitrile, vinyl chloride, vinylidene chloride,
Ethylene, propylene, phtadiene.

Homopolymers such as isoprene and chloroprene, anionic monomers such as maleic acid, fumaric acid, hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, allyl glycidyl ether, diethyl sulfonate methacrylate, and vinyl sulfonic acid, dimethyl Aminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate), tert-butylaminoethyl (meth)acrylate and quaternary salts of Toro et al.

Cavionic monomers such as vinylpyrrolidone and vinylpyridine are used.

Examples of the polymeric protective colloid in ti(4) include cellulose derivatives such as methylcellulose, hydroxyethylcellulose, and carboxymethylcellulose, starch derivatives such as phosphate esterified starch, sodium alginate, casein, gelatin, and glue.

Natural resins and plant resins such as gum arabic and mannan, (
meth)acrylic acid, itaconic acid, maleic polyacrylamide, polyvinylpyrrolidone, polyvinylmethyletheramine resin, polyethylene.

Synthetic polymers such as imine and polyethylene oxide are used.

Next, among the hydrophilic polymers used in the present invention, all of the water-soluble 01 fats used as the polymer protective colloid for emulsion paper mounts are used. Of course, several of these can also be used in combination. It is possible.

The pigment used in the present invention is kaolin.

clay, bentonite, merck, montmorillonite.

Acid clay, silicic acid, aluminum silicate, magnesium silicate, alumina, r*, zincide, titanium oxide.

Calcium carbonate, magnesium carbonate, metal soaps, magnesium oxide, magnesium hydroxide, calcium hydroxide, calcium oxide, barium sulfate.

Examples include organic pigments containing inorganic materials such as tin oxide, zeolite, diatomaceous earth, and satin white, and specific fillers such as urea-formalin resin, polystyrene powder, and starch particles, which may be used alone or in combination.

Next, as the waterproofing agent used in the present invention, amino resin, glyoxal, epoxidized polyamide, polyamine, zirconium complex salt, dialdehyde starch, etc. are used individually or in combination with a catalyst.

In addition, dispersants such as sodium pyro-11phosphate and sodium metaphosphate can be used as necessary.

The purpose of the present invention can be fully achieved by applying a treatment agent comprising the above-mentioned five components as essential components to the support, but in order to obtain even greater effects, the blending ratio of each component must be adjusted as follows. It is more preferable to fall within the range shown in Table 1.

According to Table 1, there are two classifications depending on the type of conductive substance used. The conductive substances ■■■ are inorganic salts, organic hygroscopic substances, and polymer electrolytes, and ■■■ are metal fine powder and conductive metal oxide, respectively.

It is carbon black.

Any method can be used to apply the treatment agent to the support, and examples thereof include coating, spraying, size pressing, and impregnation.

Examples of the support include paper, cloth, film, non-woven fabric, composites of these, or materials laminated with metal fish scraps or metal foil, as well as paper pre-mixed with a conductive material or mixed fabric.・The following 1. The present invention will be specifically explained using examples. 5.
Of course, the present invention is not limited to this.

Four pieces of Example 1 were placed in a Lof flask at 65°C and the stirring speed was 85Q.
Polymerized for 28.5 hours at r, p, m to form 9 particles (-
A tau-free polystyrene emulsion (having an angle of 080°) was obtained. Using the obtained emulsion, a treatment agent having the composition shown in Table 2 was prepared, and it was coated on both sides of commercially available high-quality paper (64 hats) using a Meyer bar so that half of the amount after drying would be 5 sheets on each side. Drying was performed at 120°C for 5 minutes to obtain a conductive base paper.

Note that (a) a conductive substance, (b) a pigment, (→soap-free emulsion) a hydrophilic polymer binder, and a water-resistant agent.

Next, various performance tests were conducted using the obtained conductive base paper.

(Water resistance test) The sample was immersed in water (20"C) for 1 hour, pulled out and weighed. The weight after drying at 120℃ for 10 minutes was measured, and the difference in weight was expressed as percentage parts). .

(Solvent resistance test) In the same way, immerse in toluene for 1 hour and calculate the 1 weight difference.
).

(Conductivity test) After seasoning the sample at 20°C for 48 hours in an atmosphere with relative humidity of 20%, 60%, and 90 degrees, the volume sample was calendered using a Keithley resistance meter. , after smoothing for about 150 seconds.

After drying, a photoconductive layer consisting of 100 parts of Zn0 for electrophotography, 180 parts of acrylic resin for electrophotography, and 0.1 parts of toluene was applied with a Meyer bar to a thickness of 20 sheets, and dried at 120°C for 8 minutes. and obtained electrophotographic paper. After dark seasoning (48 hours) under the same three humidity conditions as in the conductivity test, nine drawings were made using a Lif-B5-220 copying machine.

The results of these tests are shown in Table 3, and show good water resistance, high conductivity with little resistance change even over a wide range of humidity changes, and good solvent resistance, with good electrophotographic images. Extremely clear copies were obtained under all mild and mild conditions.Even when a sample was stored at 20°C and 260% relative!・g-・7・humidity for 6 months, extremely clear copies were obtained, and even after storage over time, It was also found that the properties were excellent.

Examples 2 to 7 Next, in the same manner as in Example 1, only the blending ratio of the components in Table 2 was changed as shown in Table 8, samples of Examples 2 to 7 were created, and the same tests were conducted. As a result, all samples showed extremely good water resistance, solvent resistance, and conductivity.
A clear electrophotographic image was obtained, and there were no problems with storage over time. 0 Comparative Examples 1 to 8 Sodium dodecyl nitrate 2 parts KOH 0.5 parts Styrene monomer 100 parts Ammonium persulfate 0.8 parts Water 800 parts in a fast flow 4 of them were placed in a Loftusco with a cooler and polymerized at 70℃ for 4 hours with slow stirring to obtain a normal styrene emulsion using a surfactant. ) and (e) to prepare samples of Comparative Examples 1 to 8 with the formulations shown in Table 3.

Various tests were conducted.

Comparative Example 1 contains a large amount of hydrophilic polymer binder and has good solvent resistance, but lacks water resistance and changes in conductivity due to changes in humidity are severe.At 20% humidity, non-image areas The result was an image with severe fog, and at 60%, the image was somewhat good, but some unevenness was observed, and at 90%, even more severe unevenness occurred.

When this was stored for 6 months and then printed, only very low-density images were obtained, and deterioration due to storage over time was observed.

Comparative Example 2 has a large amount of hydrophobic polymer emulsion components,
Although the water resistance was relatively good, the solvent resistance was completely inadequate, and numerous bubbles were observed even after the photoconductive layer was coated and dried. When I drew this, that part became a spot. In addition, the 0 image, which also had stains due to penetration of the toner liquid, had a considerably low density and was unclear. Comparative Example 8 is an intermediate formulation between Comparative Examples 1 and 2.

The performance shared the disadvantages of both, and the performance of both was inferior.

Example 8 Water 180 shoyu was placed in a military kettle and heated at 60°C for 24 hours at 450 r, p, m.

An anionic azobis-type soap-free emulsion was obtained. Using this, the following formulation of processing agent (85%
Aqueous dispersion) was obtained.

Add the processing agent to 749 Vn of solid proportion (c) → housing ratio (b) urea-formalin gruel powder 7wt%? A conductive substrate was obtained by spray coating both sides of a medium-quality paper so that it had a thickness of 15 sheets after drying, and water resistance, solvent resistance, and conductivity tests were conducted in the same manner as in Example 1. properties, solvent resistance, and electrical conductivity. A dielectric layer for electrostatic recording having the following composition was applied to the base paper after drying for about 10 minutes.
f/rr? Meyer bar coating was applied to obtain electrostatic recording paper.

Polyester resin 100 parts Silica 80 parts Toluene 150 parts When the obtained recording paper was subjected to an electrostatic recording fax machine at room temperature, an extremely clear and dense image was obtained. Moreover, this remained unchanged even under environmental conditions of relative humidity of 20 to 90%. This was stored at 20°C and 60% ratio for 6 months and 9 drawings were made.

Again, the same clear image as before was obtained in Example 0.
9 Diethylamine ethyl methacrylate
5 parts styrene monomer/butadiene monomer = 1/1
95 parts Azobisin butyronitrile
0.5 parts of water 120 sho 3 was placed in a pressurized container and subjected to high-speed vibration at 60°C for 15 hours to obtain soap-free styrene having a cationic particle surface.
A butadiene copolymer emulsion was obtained. Using the emulsion, a processing agent (25% aqueous dispersion) having the following composition was prepared.

(b) Silica
40 (c)) (e) Gravure coating was applied to both sides of a tracing paper with a ratio of 5 to 7♀ so that after drying there were 6 sheets.

A conductive substrate was obtained. When the same test as in Example 1 was conducted using this, as shown in Table 8, it had excellent water resistance and solvent resistance, and had little change in conductivity due to changes in humidity. Even though the photoconductive layer is applied, the quality of each image is very good, and the image is bright and has a high density (20% ratio) L~
90% I (, I obtained under soil humidity conditions. Furthermore, 6
An extremely clear image was obtained even after the sample had been stored for several months (20°b) without any change from the original. /1/1 1
00 parts Azobisisobutyronitrile
0.2 parts water
800 parts were placed in a stainless steel autoclave and stirred at 58°C at 80 Or, p, m, to a temperature of approx.
In a few hours, a protective colloidal terpolymer emulsion was obtained.

Using this, create a treatment agent (40% aqueous dispersion) with the following composition, and soak it in the base paper for impregnation (74 mm) # (b) talc 2 Qwt ratio (c)) (e) ratio. After drying, the amount of impregnation was 15 degrees.After being treated with a super calender, the same test as in Example 1 was conducted, and the result was water resistance and 11 degrees of water resistance.

When electrophotographic paper was prepared with good conductivity and a photoconductive layer similar to that in Example 1, it produced very clear images.
#! obtained, and for 6 months (20-C, 60%ait)
Even in the sample after m hours, there was no change in the same way. (Note 1) (a) Conductive substance (b) Pigment r-3-3 hydrophobic emulsion ~ soap Free emulsion) Hydrophilic polymer binder (E) Water resistance agent.

(Note 2) In the case of Examples 1 to 7, (a) and (b) in Table 2
H (→ (E)) Mix and use each component as above.

(Note 8) In the case of Examples 8 to 10, each component of (a), (b), e, sea urchin, and (e) is as described in each example.

(Mori 4) In the case of Comparative Examples 1 to 8, e is a normal polystyrene emulsion using a surfactant, and the other components are (a) and (a) in Table 2, the same as in Example 1. b) to)(
(e) is mixed and used as above.

(Note 5) Image tests are the uniformity, density, and resolution of two images on electrophotographic paper or electrostatic recording paper.

Visual clarity including capri (background smudge) is qualitatively evaluated and displayed as shown below.

# If the image is bright, mark O. If the image is a little unclear, mark Δ. If the image is unclear, mark X. The aging test refers to samples after being stored for 6 months at 20°C and 60% relative humidity. This is an image test.

Patent Applicant: Kojin Co., Ltd. Written Amendment to Procedures January 2/7, 1980 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office ■, Case Indication 1988 Patent Application No. 188201 2, Name of Invention Conductive Substrate for Recording Material 8 , Relationship to the case of the person making the amendment Patent applicant address: Claims column of the specification, Shinbashi-chome 1-1, Minato-ku, Tokyo Claims (1) On the support (a) Conductive material ( (b) A pigment (c) A hydrophobic polymer emulsion with a) a hydrophilic polymer binder (e) A treatment agent whose essential component is a water-resistant agent (c) A hydrophobic polymer emulsion with a surfactant as an anchor A soap-free emulsion conductive substrate obtained by emulsion polymerization without using soap.

Claims (1)

[Claims] (1) For recording materials in which a support is treated with a treatment agent whose essential components are (a) a conductive substance, (b) a pigment, c, a hydrophobic polymer emulsion, a hydrophilic polymer binder, and (e) a water-resistant agent. 1. A conductive substrate for a recording material, wherein the C hydrophobic polymer emulsion is a soap-free emulsion obtained by emulsion polymerization without using a surfactant.