JPH04195142A - Substrate for recording sheet - Google Patents

Abstract

PURPOSE:To obtain a substrate for a recording sheet having superior electrical conductivity and superior adhesive property of the electrically conductive layer to the base and a high resistance dielectric by incorporating polyolefin-based resin consisting of structural units of ethylene, acrylate and acrylamide into the electrically conductive layer. CONSTITUTION:Polyolefin-based resin consisting of 65-99mol% structural units of ethylene represented by formula I, 0-15mol% structural units of acrylate represented by formula II and 1-35mol% structural units of acrylamide represented by formula III is incorporated into the electrically conductive layer of a substrate for a recording sheet. In the formula II, R<1> is 1-4C alkyl. In the formula III, R<2> is 2-8C alkylene, each of R<3> and R<5> is 1-4C alkyl and R<5> is 1-12C alkyl, etc. The electrically conductive layer has a great affinity for a high resistance dielectric and a substrate for a recording sheet having superior electrical conductivity can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a support for recording sheets. More specifically, there are electrostatic recording media that convert electrical signals corresponding to characters and figures into electrostatic images and record them, and electrophotographic recording media that convert optical signals into electrostatic images and record them using electrophotography. The present invention relates to a support for a recording sheet that can be suitably used.

[Conventional technology]

Generally, supports for recording sheets are obtained by coating one or both sides of a film-like material such as paper or polyester film with a polymer electrolyte such as polyvinylbenzyltrimethylammonium chloride or a conductive agent such as an ionic activator. ing.

However, since all of these conductive agents exhibit hydrophilic properties, their conductivity changes depending on humidity, and as a result, when used as an electrostatic recording material, there is a problem that the electrostatic recording performance changes depending on humidity. Ta.

Methods to solve the above problem include a method of vapor depositing a metal and a method of applying a binder added with a conductive filler, but these methods have a problem of high cost due to complicated steps. Furthermore, when these methods are applied to electrophotographic recording materials, there is a problem that naturalness is lost due to coloring.

Furthermore, conventional conductive agents have hydrophilic groups such as cationic or anionic groups, but the high-resistance dielectric layer coated on the conductive agent contains silicone, vinyl chloride resin, and vinyl acetate. Because lipophilic resins such as copolymers, polyacrylic esters, and polystyrene are used,
There was a problem that the compatibility between the two was poor, making it difficult to coat the high-resistance dielectric layer uniformly on the conductive layer, and resulting in unclear images.

Further, there is a problem that conductive agents having a relatively small molecular weight, that is, those having a weight average molecular weight of 1000 or less, migrate to the substrate or high-resistance dielectric material over time, impeding recording performance.

In addition, in methods of vapor depositing metals or applying binders added with conductive fillers, there is no affinity between the metal film and the applied high-resistance dielectric layer, so the substrate must be undercoated with an adhesive before vapor deposition. Furthermore, in the method of applying a binder containing conductive filler,
There is a problem in that the recorded image becomes unclear because the adhesiveness changes depending on the type of binder.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned prior art,
The object of the present invention is to provide a support for a recording sheet that not only has excellent conductivity but also has excellent affinity between a conductive layer and a high-resistance dielectric material.

[Means for Solving the Problems] The present invention provides a support for a recording sheet comprising a conductive layer on a substrate, comprising 65 to 99 mol% of ethylene structural units represented by the formula E-CH2-CH2+, - General formula: % formula % (in the formula, 1.I represents an alkyl group having 1 to 4 carbon atoms) 0 to 15 mol% of acrylate structural units and general formula: (in the formula, R2 is an alkyl group having 2 to 8 carbon atoms) an alkylene group, R and R4 are each an alkyl group having 1 to 4 carbon atoms, R5 is an alkyl group having 1 to 12 carbon atoms, an arylalkyl group having 1 to 12 carbon atoms, or an alicyclic alkyl group having 1 to 12 carbon atoms, X is a halogen atom, CH30S03 or C2H50SO3
acrylamide structural units 1 to 35 represented by
The present invention relates to a support for a recording sheet, characterized in that it is a polyolefin resin layer containing a polyolefin resin layer having a weight average molecular weight of 1000 to 51111 [111] arranged irregularly in a linear manner.

[Function and Examples]

As described above, the recording sheet support of the present invention has an ethylene structural unit 65 represented by the formula K+CH-CH2+.
~99 mol%, general formula: →CH2-CH÷■0OR1 (in the formula, R1 represents an alkyl group having 1 to 4 carbon atoms) and 0 to 15 mol% of acrylate structural units and the general formula: (in the formula , 2 is an alkylene group having 2 to 8 carbon atoms, R3 and R4 are each an alkyl group having 1 to 4 carbon atoms, R5 is an alkyl group having 1 to 12 carbon atoms, an arylalkyl group having 1 to 12 carbon atoms, or an arylalkyl group having 1 to 12 carbon atoms. ~12-ring alkyl group, X represents a halogen atom, CH08O3 or C2H50S03) Acrylamide structural unit consisting of 1 to 35 mol% linearly irregularly arranged weight average molecular weight 1
A polyolefin resin layer containing a polyolefin resin of 000 to 50,000 is provided as a conductive layer.

The proportion of the ethylene structural unit represented by the formula ni(-C)+2-C12+ in the polyolefin resin is 65 to 99 mol%. When the proportion of the ethylene structural unit is less than 65 mol%, the softening point of the polyolefin resin becomes low, resulting in tackiness and stickiness, and when it exceeds 99 mol%, the polyolefin resin conductivity becomes too small. In addition, in the present invention, the proportion of the ethylene structural unit is 8% from the viewpoint of softening point and conductivity balance.
Particularly preferred is 5 to 97 mol%.

The proportion of acrylate structural units represented by the general formula: % (in the formula, R1 is the same as above) in the polyolefin resin is 0 to 15 mol%.

If the proportion of the acrylate structural unit exceeds 15 mol %, the softening point of the polyolefin resin decreases, resulting in tackiness or stickiness. In the present invention, it is preferable that the acrylate structural unit is contained because it imparts toughness and impact resistance. In the present invention, the proportion of the acrylate structural unit is particularly preferably 1 to 15 mol%, particularly 3 to 7 mol%, from the viewpoint of a balance between softening point, toughness, and impact resistance.

In the acrylate structural unit, 1 represents a carbon number of 1 to
4 is an alkyl group. As a specific example of such R1,
Examples include methyl group, ethyl group, n-butyl group, i-propyl group, dobutyl group, and 1-butyl group, and these groups may be mixed in one molecule. Among these groups, methyl and ethyl groups are preferred in order to maintain the softening point of the polyolefin resin.

General formula in the polyolefin resin: (wherein, R, R
, R and R5 are the same as above), the proportion of the acrylamide structural unit is 1 to 35 mol%. If the proportion of the acrylamide structural unit is less than 1 mol %, the conductivity becomes too low, and if it exceeds 35 mol %, the polyolefin resin becomes hygroscopic. In addition, in the present invention, the proportion of the acrylamide structural unit is particularly preferably 3 to 15 mol% from the viewpoint of the balance between conductivity and hygroscopicity.

In the acrylamide structural unit, 2 represents 2 carbon atoms.
~8 alkylene group. Specific examples of such R2 include, for example, ethylene group, propylene group, hexamethylene group, neopentylene group, etc., and these groups may be mixed in one molecule. Among these groups, ethylene groups and propylene groups are preferred from the viewpoint of ease of production and economy, with propylene groups being particularly preferred.

Specific examples include methyl group, ethyl group, propyl group, and butyl group, and these groups may be mixed in one molecule. Note that among these groups, methyl and ethyl groups are preferred from the viewpoint of electrical conductivity.

R5 is an alkyl group having 1 to 12 carbon atoms, and examples of carbon atoms include methyl group, ethyl group, n-propyl group,
Alkyl groups such as i-propyl group, n-butyl group, 5ec-butyl group, mu-octyl group, n-lauryl group; arylalkyl groups such as benzyl group and 4-methylbenzyl group; cyclohexyl group, methylcyclohexyl group, etc. Examples include alicyclic alkyl groups, and these groups may be mixed in one molecule. Note that R5 is preferably a linear alkyl group or an arylalkyl group from the viewpoint of heat resistance, and is preferably a lower alkyl group from the viewpoint of electrical conductivity. Particularly preferable examples of R5 include a methyl group and an ethyl group.

The X is, for example, a halogen atom such as CI, Br, or 1, CH30S03 or C2H50S03, and these may be mixed in one molecule. Note that among these, C1, CH30S03, and CH0803 are preferable from the viewpoint of conductivity.

The weight average molecular weight of the polyolefin resin is 100
It is 0-50000. If the weight average molecular weight is less than 1,000, the molecular weight becomes too small and volatilizes when heated, and if it exceeds 50,000,
When melted, the viscosity becomes too high and workability becomes poor. The preferred weight average molecular weight is 3000 to 30000.
It is.

Note that the weight average molecular weight in the present invention refers to a weight average molecular weight in terms of monodisperse polystyrene measured by gel permeation chromatography (GPC).

The polyolefin resin used in the present invention is poorly soluble in ordinary gel permini-silane eluents such as tetrahydrofuran (TBF) and xylene, so its weight average molecular weight cannot be easily measured.
For silk, Polymer Papers, Volume 44, No. 2, H9-+41 pages (
19117)).

The formula of the intermediate of the polyolefin resin: →CH2
Ethylene structural unit represented by -CH2+, general formula: %formula%) (wherein, R1 is the same as above), lylate structural unit and general formula: (wherein, R, R and R4 are as above) An olefin copolymer having a weight average molecular weight of 1,000 to 5,000 G and having linearly irregularly arranged acrylamide structural units represented by (the same) can be obtained, for example, by the following method.

First, the raw material for the olefin copolymer is not particularly limited, but it is more advantageous to use a (partial) hydrolyzate of a copolymer consisting of an acrylate represented by (ethyl). A copolymer that is loose can be easily obtained by copolymerizing ethylene and the above-mentioned acrylate using a high-pressure polymerization method.

The ratio of the ethylene structural unit derived from ethylene and the acrylate structural unit derived from the acrylate determines the ratio of the ethylene structural unit, acrylate structural unit, and acrylamide structural unit of the resulting olefin copolymer.

Since the copolymer usually has a high molecular weight with a melt index of about 5 to 300, it can be reduced in molecular weight by, for example, a degradation method in which hydrolysis and thermal decomposition are simultaneously carried out in the presence of water at high temperature and high pressure. It is preferable.

At this time, all or part of the acrylate structural unit represented by the general formula: % formula % (in the formula, R1 is the same as above) resulting from acrylate is hydrolyzed to form an acrylic acid structural unit represented by the formula: % formula % becomes.

The copolymer is thermally decomposed to lower its molecular weight, and in order to prepare a copolymer with a weight average molecular weight of 1,000 to 50 (Ill(l), the copolymer is heated in the presence of water at a reaction temperature of 150 to 50. The molecules may be cut by heating at 500° C. and a pressure of 3 to 500 kg/al.

Furthermore, in the present invention, the proportion of the acrylic acid structural units can be adjusted as appropriate by adjusting the amount of water, reaction temperature, pressure, and reaction time.

As a specific example of the above-mentioned degradation method, for example, JP-A-53-
No. 57295, Japanese Patent Application Laid-open No. 53-653119,
JP-A-60-79008, JP-A-60-7901
Examples include the method described in Publication No. 5 and the like.

Note that if the polyolefin resin used in the present invention is colored, it may impair its commercial value.
It is preferable to use the product of the method exemplified in Publication No. 79008.

The polyolefin resin intermediate thus obtained can be used to convert the polyolefin resin used in the present invention.

There are no particular limitations on the method for producing the polyolefin resin used in the present invention from the intermediate. An example will be explained below.

The intermediate may be, for example, benzene, toluene, xylene,
Dissolved in an inert solvent such as an aromatic or aliphatic hydrocarbon such as cyclohexanone, decane, cumene, cymene, etc.
A dialkylamine monomer such as 0 mol% dialkylaminoalkylamine was added and reacted at 130 to 220°C to convert the carboxyl group contained in the acrylic acid structural unit to a dialkylaminoalkylamide group to obtain an intermediate. Thereafter, the polyolefin resin, which is a linear random copolymer used in the present invention, is changed by cationic modification with a known quaternizing agent such as an alkyl halide or a dialkyl sulfate.

(The resulting polyolefin resin exhibits excellent electrical conductivity.The reason why it exhibits such electrical conductivity is not clear, but the acrylamide structural unit contained in the polyolefin resin absorbs moisture contained in the air. This is thought to be due to the fact that xe exhibits low electrical resistance due to ionization and electrical conductivity.

Furthermore, in the present invention, the acrylamide structural unit does not exhibit volatility even at high temperatures and is chemically incorporated into the polyolefin resin used in the present invention, so there is no volatilization during processing. It is considered that no blocking occurs after processing.

The recording sheet support of the present invention is one in which a resin containing the polyolefin resin described above is provided on a substrate as a conductive layer. For the conductive layer, the polyolefin resin alone or a mixture of the polyolefin resin and another polyolefin resin is used.

Examples of the other polyolefin resins include polyvinyl acetate, ethylene-vinyl acetate copolymer, saponified product of the ethylene-vinyl acetate copolymer, and ethylene-vinyl acetate copolymer.
(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-(meth)acrylic acid-maleic anhydride terpolymer, ethylene-(meth)
Examples include acrylic acid ester-maleic anhydride terpolymer and vinyl acetate-(meth)acrylic acid ester copolymer, and these resins may be used alone or in combination of two or more types.

In addition, when the above-mentioned polyolefin-based resin and the above-mentioned other polyolefin-based resin are used together, the amount of the above-mentioned polyolefin-based resin used is 1 part (by weight, the same applies hereinafter) for 100 parts (parts by weight, the same applies hereinafter) of the resulting conductive layer resin. Above, preferably 5
In order to impart conductivity, it is desirable that the amount is at least 50%.

There is no particular limitation on the method of providing the conductive layer on the substrate, and for example, the conductive layer resin may be coated as it is or as an emulsion by a reverse roll coating method, a gravure coating method, a bar code method, etc. can give.

The thickness of the conductive layer after drying is adjusted as appropriate depending on the use of the electrostatic recording material that is usually obtained, but is usually 0.1 to 5 um.
, and about <0.5 to 3 um.

Furthermore, depending on the required electrical resistance value, one surface of metal powder or inorganic fine particles may be plated with a metal such as gold tin or copper in a range of 20% by weight on the formed conductive layer. It may be added to control the resistance value.

Examples of the substrate in the present invention include paper made of natural fibrous pulp, synthetic paper made of synthetic resin fibrous pulp, synthetic paper made of resin such as polycarbonate, styrene polymer, two-wheel stretched polyester, and polymethyl methacrylate. However, the present invention is not limited to such examples.

When an electrostatic recording paper is hung by providing a high resistance dielectric layer on a conductive layer formed on a substrate, known resins can be used as the resin for the high resistance dielectric layer. That-
An example is one in which fine inorganic powder is blended with a highly conductive resin.

The resin for the high dielectric layer is a resin having an electrical resistance of 1012Ω or more, and specific examples thereof include vinyl chloride, vinyl acetate, vinyl acetal, vinylidene chloride, ethylene, styrene, butadiene, (meth), etc. ) Organic solvent-based or water-dispersed resins such as vinyl homopolymers or copolymers such as acrylic esters and (meth)acrylic acid, polycarbonates, polyolefin resins, and polyester resins.

Further, examples of the inorganic fine powder include those having a particle size of 3 μm or less, such as calcium carbonate, alumina sol, and silica sol.

The amount of the inorganic fine powder added to the high dielectric resin is usually 1 to 30 parts, especially 5 to 30 parts, per 100 parts of the high dielectric resin.
There are 20 copies.

The high resistance dielectric is provided on the conductive layer, for example as an aqueous dispersion emulsion or a solution in an organic solvent such as methyl ethyl ketone. The thickness of such a high-resistance dielectric after drying is appropriately adjusted depending on the intended use of the resulting electrostatic recording material, but is usually 0.15 to 20 μm, particularly 5 to 7 μm.

Next, the recording sheet support of the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Example 1 A linear inorganic compound consisting of 85 mol% of ethylene structural units of the formula -C12CH2+, 5 mol% of acrylate structural units of the formula: % and 10 mol% of acrylamide structural units of the formula: An emulsion solution containing 24% by weight of regularly arranged polyolefin resin with a weight average molecular weight of 313H was applied to a biaxially stretched polyester film (thickness = 125 μm).
) was coated with a barcode method to a coating density of 12 t/m2, and then supplied to a hot air drying oven at 100°C for drying. The thickness after drying was 0.5 μm.

After coating this conductor layer, the surface resistivity was measured at a temperature of 20°C and a relative humidity (R) of 20%, 40%, 60% or 80% according to the following method, and the results were 9.[ 1XIO'Ω, ?, 5XI (17Ω, ?, 0X
It exhibited extremely excellent conductivity of 1G7Ω and 6.11XI07Ω, and the humidity dependence of the resistance value, which was a drawback of conventional conductivity by ionic conduction, was improved, and the humidity dependence of the resistance value was extremely small.

The conductive layer surface of the substrate coated with this conductive layer contains 20% by weight of light calcium carbonate fine powder surface treated with ethylene-acrylic acid (acrylic acid concentration 20% by weight) copolymer and ethylene-imine coupling agent. The water-dispersed emulsion solution was coated using the barcode method to a thickness of 5 μm to form a high-resistance dielectric layer.
It was supplied to a hot air drying oven at 110°C and dried.

This material was placed in an atmosphere of 20° C. and 60% RH for 24 hours to control the humidity and obtain an electrostatic recording material. The back side of the coating layer of this electrostatic recording material was reinforced with cellophane adhesive tape, and the cellophane adhesive tape was attached to the reinforced coating layer surface and quickly peeled off by 180 degrees. No peeling was observed, and cohesive tearing of the high-quality paper occurred, indicating that the adhesive was in good condition.

This electrostatic recording material could be suitably used as an electrostatic master or an electrophotographic master.

(Surface specific resistance) Cut the electrostatic recording body into 1cm pieces,
It is left to age for 48 hours in a constant temperature room controlled at 20° C. and 20%, 40%, 60% or 80% RH.

After aging, the surface resistivity is measured in the atmosphere.

Measuring device: ■ A new Kawaguchi Electric machine's transcendental total meter (VE-40 type) connected to a normal temperature measuring box (RC-02 type).Measurement conditions: Applied voltage +011V.The value measured by this device is adopted.

Note that a surface resistivity of 1X10'Ω or less has excellent conductivity.

Example 2 A conductive layer was formed in the same manner as in Example 1, except that the solid content of the polyolefin resin emulsion was 25% by weight and the coating was applied to a thickness of 15 μm. The thickness of the conductive layer after drying was 3 μm.

Next, the recording sheet support obtained above was smoothed by applying a spark calender. The surface resistivity of this material is 6
．． It was 7×10 ohms.

After lining the back side of the substrate of the obtained recording sheet support with cellophane adhesive tape, a peeling test was performed on the coated surface using the cellophane adhesive tape, but no peeling of the coated surface was observed.

On the conductor layer, acrylic resin (manufactured by Mitsubishi Rayon ■, LR
472) A solution of 20 g of talc and 4 g of talc added to 76 g of methyl ethyl ketone was prepared using the bar code method to obtain a solution with a thickness of 30 μm.
m and dried to form a high resistance dielectric layer.

A peel test was performed on the obtained recording sheet in the same manner as above, but no peeling between the coating layer and the high-resistance dielectric layer was observed.

Example 3 A support for a recording sheet was obtained in the same manner as in Example 2, except that a polyolefin resin having an acrylamide structural unit represented by the formula: % Formula % was used.

When the physical properties of the obtained recording sheet support were examined, as with the support obtained in Example 2, no peeling of the coating layer from the substrate was observed. After coating and drying, the electrostatic recording material obtained did not exhibit any peeling, similarly to the material obtained in Example 2, and exhibited good adhesion.

Comparative Example 1 A 25% emulsion solution of a cationic polymer conductive agent (polyvinylbenzyltrimethylammonium chloride) was applied as a conductive agent to the same substrate as in Example 1, with a film thickness of 2 after drying.
After coating to a thickness of .mu.m, the same high-resistance dielectric as in Example 1 was coated to obtain a support for a recording sheet.

The base surface of the obtained recording sheet support was lined with a cellophane adhesive tape, and a peel test was performed on the coated surface using the cellophane adhesive tape. As a result, peeling between the conductive layer and the high-resistance dielectric layer was observed.

Comparative Example 2 A cationic polymer conductive agent (poly(N, N
-dimethyl-3,5-methylenepiperidinium chloride)), styrene resin (Tissan Resin Nl0I: manufactured by Teikoku Kasei ■) and acrylic resin (Acridic?-1021: Ten Nippon) as the high-resistance dielectric layer resin components. 30% by adding 40% by weight of calcium carbonate to a 1.25:1 (weight ratio) mixture of Ink Kagaku Kogyo ■)
A support for a recording sheet was obtained in the same manner as in Example 1 using a toluene solution.

The coated back side of the obtained recording sheet support was lined with cellophane adhesive tape, and a peel test of the coated side with the cellophane adhesive tape revealed that the difference between the conductive layer and the high-resistance dielectric layer was similar to that obtained in Comparative Example 1. Peeling was observed.

[Effects of the Invention] The recording sheet support of the present invention not only has excellent conductivity, but also allows the substrate, conductive layer, and high-resistance dielectric to be bonded together without using a binder to improve adhesion. It has excellent sex.

Therefore, the recording sheet support of the present invention can be suitably used for electrostatic masters, electrophotographic masters, etc. in the field of information transmission that uses electrostatic recording.

Master 8;

Claims (1)

[Scope of Claims] 1. A recording sheet support comprising a conductive layer provided on a substrate, the conductive layer comprising 65 to 99 moles of ethylene structural unit represented by the formula: ▲There are numerical formulas, chemical formulas, tables, etc. %, general formula: ▲There are numerical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 represents an alkyl group having 1 to 4 carbon atoms) 0 to 15 mol% of acrylate structural units and general formula: ▲ There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^2 is an alkylene group with 2 to 8 carbon atoms, R^3
and R^4 are each an alkyl group having 1 to 4 carbon atoms, R
^5 is an acrylamide structural unit represented by an alkyl group having 1 to 12 carbon atoms, an arylalkyl group having 1 to 12 carbon atoms, or an alicyclic alkyl group having 1 to 12 carbon atoms; A support for a recording sheet, characterized in that it is a polyolefin resin layer containing a linearly irregularly arranged polyolefin resin having a weight average molecular weight of 1,000 to 50,000 and comprising 1 to 35 mol%.