JPH0333853A - Electrostatic recording film - Google Patents

Abstract

PURPOSE:To improve the fixability to a tape peeling and the fixability to scratching flaws by applying a specific high-polymer binder to an insulating layer. CONSTITUTION:The insulating layer contains the high-polymer binder and insulating spacer particles. The high-polymer binder contains at least one kind selected from polyester having (A)<=100% tensile elongation at break specified by ASTM D638-61T and at least one kind selected from the polyester having (B)>=300%, the weight ratio of which is A/B=60/40 to 20/80. Sharp images are not obtainable by printing after long-term preservation if the weight ratio of (B) increases and the fixability to scratching flaws is degraded if the ratio is smaller than the above-mentioned range. Not only the fixability to the tape peeling but the fixability to the scratching flaws are improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an electrostatic recording film, and particularly to an electrostatic recording film that directly transmits electrical signals through a sieve. This invention relates to an electrostatic recording film that converts into a latent image and then develops with toner to create a visible image. More specifically, the present invention relates to an electrostatic recording film used in electrostatic printers and plotters for CAD (interactive design) and the like.

(Prior Art) An electrostatic recording film is known in which an insulating film, a conductive layer, and an insulating layer are laminated in this order.

In the electrostatic recording method, a recording voltage is applied to a multi-bin electrode head (hereinafter abbreviated as a bin electrode), and an air discharge is generated in a micro gap (hereinafter abbreviated as a gap) between the bin electrode and the insulating layer of an electrostatic recording film. 41t on the surface of the insulating layer? VI
An image is formed and then this electrostatic latent image is developed with toner to form a visible image.

In order to obtain clear images in this way, it is necessary to control the gap within an appropriate range from the Paschen curve, and for this purpose, by adding insulating spacer particles and bringing the bin electrode into contact with an insulating layer that has been provided with appropriate irregularities. The most commonly used method is to properly control the gap.

On the other hand, fixing of toner images on such electrostatic recording film is
Conventional electrostatic recording film does not have sufficient fixing properties compared to electrostatic recording paper because it is simply left as it is without applying heat or pressure. There was a drawback that the toner image easily peeled off from the insulating layer.

As a means for improving the fixability of a toner image, as a polymer binder, (A) at least one selected from halogenated polyolefins containing 60 to 80% by weight of halogen and (B) Tg are added to the insulating layer. Contains at least one selected from a polyester copolymer having a temperature of 20°C or less and/or a poly(meth)acrylic acid ester copolymer having a Tg of 20°C or less, and the weight ratio is A/B=98/ 2-501
It is reported that 50 is necessary.

(Japanese Patent Application Laid-Open No. 63-184758) Although it is true that the above invention improves the fixing properties due to tape peeling, it does not improve the fixing properties caused by scratches with fingernails, etc., and furthermore, it does not improve the fixing properties caused by scratches with nails, etc. When exposed to irradiation, the print density decreased and thin lines broke, making it unusable for CAD drawings that require precision drawings.

The present inventors have conducted intensive studies on improving the fixing properties of toner images formed with liquid toner on electrostatic recording films, and have found that a polymer that improves not only the fixing properties against tape peeling but also the fixing properties against scratches. The present invention was achieved by discovering that a combination of binders exists.

(Problems to be Solved by the Invention) The purpose of the present invention is to eliminate the above-mentioned drawbacks, that is, to improve not only the fixing property against tape Il+ separation but also the fixing property against scratches, and to achieve high-speed recording even after long-term storage. The object of the present invention is to provide an electrostatic recording film that can produce high-quality images with less loss of density and fewer thin lines.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration. That is, in an electrostatic recording film in which an insulating film, a conductive layer, an insulating layer containing a polymer binder and insulating spacer particles are laminated in this order, AST is used as the polymer binder.
The tensile elongation at break according to M D638-61T is (A)
At least one selected from 100% or less polyester
Contains at least one species selected from seeds and (B) 300% or more polyester, the weight ratio of which is A/B-60/4
It is characterized by an electrostatic recording film having a ratio of 0 to 20/80.

Polyesters (A) and (B) for the polymer binder used in the insulating layer of the present invention are selected from commonly known polyesters and have the above-mentioned tensile elongation at break.

Such polyesters are obtained by copolymerizing polyhydric carboxylic acids and polyhydric alcohols, and polyhydric carboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and succinic acid. acids, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, trimellitic anhydride, etc., and polyhydric alcohols such as ethylene glycol, 1,4-butanediol, and ■.

5-bentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, propylene glycol, neopentyl glycol, 154-cyclohexanedimethanol, pentaerythritol, trimethylolpropane, etc. are preferably used. Ru.

More preferred is a linear polyester that is a copolymer of dihydric alcohol and dihydric carboxylic acid.

(A) and (B) weight ratio is A/B = 60/40 to 20/8
It needs to be 0 and is preferably selected within this range. More preferably A/B=55/45 to 25/7
5 is desirable.

If the weight ratio of B is higher than this, a clear image cannot be obtained in printing after long-term storage, and if it is lower than this, the fixing property against scratches will deteriorate.

In the insulating layer of the present invention, known polymer binders, plasticizers, adhesion promoters, stabilizers, Antioxidants, ultraviolet absorbers, lubricants, etc. may be added, and
Conductive powder etc. may be added to prevent fogging.
In this case, the amount of the known polymer binder added to 1 part of the polymer binder of the present invention is preferably 2 Offiffi parts or less. The polymer binder of the present invention particularly improves the fixing properties of organic polymer particles.

As an insulating spacer particle, the volume resistivity is 10@Ω・
Commonly known inorganic particles and/or organic polymer particles having a diameter of 0 or more, more preferably 10I0 Ω·cm or more are used.

Examples of such inorganic particles include metal oxides such as silicon oxide, titanium oxide, aluminum oxide, lead oxide, and zirconium oxide; salts such as calcium carbonate, barium titanate, and barium sulfate; and organic polymer particles such as: For example, polyolefins such as polyethylene and polypropylene, starch, styrene-divinylbenzene copolymers, melamine resins, epoxy resins, phenolic resins, fluororesins,
Appropriately selected from the following. These insulating spacer particles may be used alone or in combination of two or more.

The average particle diameter of the above-mentioned insulating spacer particles needs to be projected on the insulating layer for the stability of discharge, and is related to the film thickness, but is generally selected appropriately within the range of 4 to 20 μm. preferable. The weight ratio of polymer binder and insulating particles is 10
The ratio is preferably from 010.5 to 100/100. If it is less than this, the stability of discharge will be poor, and if it is more than this, transparency will be impaired. The thickness of the insulating layer is 1~
Preferably, it is 20 μm.

The insulating layer may be a single layer or a plurality of layers.

For example, a layer made of the polymer binder of the present invention may be laminated on an insulating layer made of a commonly known polymer binder and particles. In this case, the layer made of the polymer binder of the present invention may be a layer that does not contain particles.

A specific method for adding an insulating layer is to add a dispersion of insulating particles to a solution in which an insulating polymer binder is dissolved or dispersed in a suitable solvent or water, mix uniformly, and then apply the method described above. It may be applied and dried by a commonly known method so as to obtain a film thickness.

The insulating film used in the present invention can be any commonly known film as long as it has good transparency and mechanical strength. It may be opaque depending on the purpose.

For example, the resin for this film is polyester
Polyolefins include polyamide, polyesteramide, polyether, polyamide, polyamide, polystyrene, polycarbonate poly-P-phenylene sulfide, polyether ester, polyvinyl chloride, poly(meth)acrylic acid ester, and the like.

The thickness of the insulating film is 10 μm to 250 μm.
It is preferable that it is, more preferably 15 μm to 1
The thickness is preferably 50 μm.

If it is thinner than this, the film will not have sufficient mechanical strength, and if it is thicker than this, the membrane permeability will be poor, which is not preferable.

These insulating films may be subjected to known surface treatments, such as corona discharge treatment, plasma discharge treatment, anchor coating, etc., to improve adhesion, if necessary.

Furthermore, the insulating film has a static friction coefficient of 2.0 or less, more preferably 1.0 to prevent scratches during running.
It is preferable that it is below.

In the present invention, the volume resistivity of the insulating film is not particularly limited, and is appropriately selected depending on the electrostatic recording method. That is, in addition to the insulating film, in order to prevent the generation of static electricity on the surface of the insulating film opposite to the conductive layer, if necessary, to the extent that the characteristics of the present invention are not impaired, An antistatic layer or another conductive layer may be provided on the surface of the insulating film, or an antistatic agent may be added to provide electrical conductivity between the front and back surfaces of the insulating film.

Furthermore, if necessary, a matte or colored film may be used, or a laminate of two or more types of insulating films may be used.

As for the conductivity of the present invention, a commonly known one is used, and the zero surface electrical resistance is preferably 10' to 10' Ω/hole.

Such conductive layers include (1) those made of electronically conductive metals or metal oxides, (2) those coated with ionically conductive polymer electrolytes, and (3) conductive powders and polymer binders. or those coated with a layer consisting of a polymer electrolyte.

In the present invention, so-called fogging,
A carbon electrode or the like may be provided at the end of the insulating layer as is generally known as a countermeasure against ghosts and the like.

(Effects of the Invention) The present invention provides an electrostatic recording film in which an insulating film, a conductive layer, an insulating layer containing a polymer binder, and insulating spacer particles are laminated in this order. By applying an adhesive, it is possible to obtain an electrostatic recording film that not only improves the fixing property against tape peeling but also the fixing property against scratches, and can stably produce high-quality images with high-speed recording even after long-term storage. be.

As described above, since the electrostatic recording film of the present invention has excellent properties, it can be used particularly as an electrostatic recording film for hard copies, electrostatic recording printer blocks, and facsimiles.

(Method for measuring fixability) (1) Measuring method by tape peeling After measuring the image density (initial density) of the solid black image area, attach a mending tape, then peel it off by 180".
The image density (residual density) of the peeled part is measured. A fixing rate of 60% or more was judged as good, and a fixing rate of less than 60% was judged as poor.

Residual Density Fixation Rate - xlOO (%) Initial Density (2) Measuring Method by Scratching Solid black image areas were evaluated using a continuous weighted scratch hardness tester in five grades from A to E in descending order of fixability. (B or higher is a practical level) (Storability) The obtained electrostatic recording film was left for one year, then printed, and evaluated in five grades from A to E in descending order of image quality. (B or higher is a practical level) (Examples) The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto.

(Example l) SnO□ (S
(b) Doping) An aqueous dispersion of particles and gelatin in a weight ratio of 50/l was prepared in a dry sgo to a thickness of 2 μm to obtain a conductive film with a surface electrical resistivity of 5×10 6 Ω/l.

On this conductive film, an insulating N coating liquid with the following composition was applied so that the film after drying had a thickness of 2.1μ, and heated at 100°C for 1
Dry for 0 minutes, then add 100 Ω/
A 10 cm carbon electrode was provided to obtain an electrostatic recording film of the present invention.

Images were printed using an electrostatic plotter (bar) having 16 multi-bin electrodes.

Manufactured by Satec Co., Ltd., CR2424 The initial characteristics of this electrostatic recording are The results are summarized in Table 1.

vP, edge N coating liquid toluene 40g EK 30g Rosin ester gum AA-L 2g (manufactured by Senyou Kagaku Kogyo) Polypropylene particle dispersion (20X) 6g (Unistol R100K, average particle size 8.4 μ (manufactured by Mitsui Petrochemical) (Examples-2 to 4) Byron 30 instead of Example 1 Byron 500
Samples of Examples 2 to 4 were obtained in the same manner as in Example-1 except that 0, Byron 530, and Byron CK130 were used.

(Example-5) A sample of Example-5 was obtained in the same manner as Example-1 except that Byron 290 was used instead of Byron 200 of Example-1.

(Examples 6 to 8) Byron 10 was used instead of Byron 200 in Examples 1 to 3.
Samples of Examples 6 to 8 were obtained in the same manner except that Sample No. 3 was used.

(Examples-9 and 10) Examples 9 and 10 were prepared in the same manner as in Example-1 except that the polyester ratio A/B in Example-1 was changed from 40/60 to 20/80 and 60/40, respectively. sample was obtained.

(Comparative Examples-1 to 4) The polyester ratio A/B of Example-1 was changed from 40/60 to 10/90.15/85.70/30, and 9, respectively.
Samples of Comparative Examples 1 to 4 were obtained in the same manner as in Example-1 except that the ratio was changed to 0/10. As is clear from Table 1, A/
Only the electrostatic recording film of the present invention has B in the range of 60/40 to 20/80.

See Table 1 (separate table)

Claims (1)

[Scope of Claims] [1] In an electrostatic recording film having a main layer configuration in this order of an insulating film, a conductive layer, an insulating layer containing a polymer binder and insulating spacer particles, the polymer binder A as adhesive
The tensile elongation at break according to STMD638-61T is (A)
Contains at least one type selected from 100% or less polyester and (B) at least one type selected from 300% or more polyester, the weight ratio of which is A/B = 60/4.
An electrostatic recording film characterized in that the electrostatic recording film is 0 to 20/80. (2) The electrostatic recording film according to claim 1, wherein the insulating spacer particles are organic polymer particles.