JPH0483689A - Thermal mimeograph paper - Google Patents

Abstract

PURPOSE:To obtain a printed matter having high quality and excellent punching sensitivity by layering a thermoplastic resin film on one face of a porous support body through an adhesive layer in such a manner that the surface roughness of the film in a layered state is lower than a predetermined value. CONSTITUTION:The surface roughness of a thermoplastic resin film in a state that it is layered on a porous support body is make to be 1.3 or less dependent on a selection of the porous support body or a process and further a selection of an adhesive to be used. The smaller the numeral value of the surface roughness is, the better it is. However, there exist a lower limit economically. Accordingly, a preferable surface roughness is 0.5-1.3. As for an adhesive for sticking the thermoplastic resin film to the porous support body, any adhesive can be used. However, a radiation hardening adhesive, particularly a radiation hardening adhesive consisting of polyurethane resin and monofunctional and/or (meta) acrylate is preferable. Although there is no limitation for the porous support body, for example, a paper with basis weight of 6-13g/m<2> and film thickness of 20-60mum having excellent dispersibility and surface smoothness is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a thermal mimeograph base paper, and more specifically, an object of the present invention is to provide a heat-sensitive mimeograph base paper that has excellent perforation sensitivity and provides high-quality printed matter.

(Prior art and its problems) Conventionally, the mimeograph printing method has been widely used as a simple printing method, and in this method, a thermoplastic resin film is laminated on the surface of a suitable porous support such as paper. Used as a mimeograph base paper, printed with a thermal head etc., the thermoplastic resin film is heated and melted to form perforations in the form of an image, and printing is performed on a printing material such as paper by passing printing ink from the porous support side. It is something.

In the conventional heat-sensitive mimeograph base paper mentioned above, a biaxially oriented polyester film is mainly used as the thermoplastic resin film, but perforation of this film requires considerably high energy, and sufficient perforation sensitivity cannot be obtained with low energy. First, there is a problem that the image quality of the resulting printed matter is not sufficient.

Methods for improving the perforation sensitivity and image quality of the base paper include: (1) A method for improving the thermal properties of a thermoplastic resin film (Japanese Patent Application Laid-open No. No. 62-282983, 6
2-149496, etc.), (2) A method of using porous tissue paper, which is a mixture of natural fibers and finer synthetic fibers, as a porous support (JP-A-63-059394, JP-A-60-217197). (3) Method for achieving high sensitivity and high image quality by improving adhesives (Japanese Patent Application Laid-open Nos. 147396/1986 and 62-0015)
89, JP-A-1-135693, etc.), (4) Method for achieving high sensitivity and high image quality by improving the heat-fusion prevention layer (JP-A-62-033690, JP-A-1-1999)
237196, etc.) have been proposed.

According to the above-mentioned conventional proposals, although their respective effects are recognized, the irregularities of the porous support appear on the thermoplastic resin film laminated on the surface, and the contact between the thermal head and the thermoplastic resin film is particularly poor. In many cases, it is insufficient, and the above conventional technology alone is sufficient! There is a problem in that it is not possible to obtain printed matter with high perforation sensitivity and high image quality.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the above-mentioned drawbacks and to provide a thermal mimeograph base paper which has excellent perforation sensitivity and provides high-quality prints.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a heat-sensitive mimeograph base paper in which a thermoplastic resin film is laminated on one surface of a porous support via an adhesive layer, the surface roughness of the thermoplastic resin film being
This is a heat-sensitive mimeograph base paper characterized in that Ra) is 1.3 μm or less.

(Function) A thermal mimeograph base paper that has excellent perforation sensitivity and provides high-quality printed matter by setting the surface roughness (Ra) of the thermoplastic resin film in a laminated state to 1.3 μm or less in the heat-sensitive mimeograph base paper. can be provided.

Furthermore, in a preferred embodiment of the present invention, the adhesive layer is formed of a radiation-curable adhesive that does not substantially contain a solvent, so that irregularities on the porous support can be well covered.
It has improved perforation sensitivity and excellent printing durability, and can be used as a thermal mimeograph base paper that provides high-quality printed matter.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The porous support used in the present invention needs to be porous so that the printing ink used during printing can pass through. , synthetic papers and mesh sheets made of chemical fibers such as vinylon, polyester, acrylonitrile, polyamide, etc., paper made from blends of chemical fibers with manila hemp, Kokuzo, and Mitsumata natural fibers, etc., which are used as porous supports for conventional heat-sensitive mimeograph base paper. Any of these can be used in the present invention, and is not particularly limited, but for example, a basis weight of 6 to 1
3g/rd, film thickness 20-60μm vertical/horizontal strength ratio 3
．． Paper with excellent dispersibility and surface smoothness with a fiber diameter of 5/1 to 1.5/1 and a fiber diameter of 0.05 to 2.5 deniers is preferred.

In particular, in order to further improve the surface smoothness of the thermoplastic resin film laminated thereon, it is more preferable to subject the above-mentioned support to an appropriate calender treatment.

The thermoplastic resin film itself to be laminated on the surface of the porous support may be the same as that used in conventional heat-sensitive mimeograph base paper, such as polyvinyl chloride film, vinyl chloride film, etc.
Vinylidene chloride copolymer film, polyester film, polyolefin film such as polyethylene, polypropylene, polystyrene film, etc. can all be used.
These thermoplastic resin films have a thickness of 20 tLm or less, preferably 10 μm or less, and optimally 0.5 to 2.0 μm so that perforations can be easily formed by heating means such as a thermal head. .

The surface roughness of such a film itself is usually Ra=1.
．． However, when this is laminated on the above-mentioned porous support by a conventional method, the surface roughness of the porous support appears and it is usually not possible to make RA = 1.5 or less. In the present invention,
By selecting or treating the porous support to be used, and by selecting the adhesive, it is possible to reduce the surface roughness of the thermoplastic resin film to 1.3 or less when laminated on the porous support, and this is a preferred embodiment. Then, it can be further reduced to 1.0 or less. Of course, the smaller the numerical value of the surface roughness, the better it is, but there is an economical lower limit, and therefore the preferred surface roughness in the present invention is 0. 5 to 1.3.

The adhesive used for adhering the porous support and the thermoplastic resin film may be any conventionally known adhesive, but in the present invention, a radiation-curable adhesive, particularly a polyurethane resin and a monofunctional and/or Preference is given to using radiation-curable adhesives consisting of meth)acrylates.

The polyurethane resin used in the above adhesive is obtained from polyisocyanate and polyol, and has high cohesive strength due to the presence of urethane bonds, and when mixed with (meth)acrylate monomer, the viscosity becomes significantly temperature dependent. Become a thing.

Various grades of such polyurethane resins are available on the market, and any of them can be used in the present invention, but particularly preferred in the present invention is a resin made by reacting a polyisocyanate, a polyol, and a monofunctional alcohol. This can be obtained by doing so.

Examples of the polyisocyanate to be used include toluidine diisocyanate, 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, etc., and examples of the polyol include 1,4-butanediol, 1,3- Examples include butanediol, mono (or di, tri) ethylene glycol, mono (or di, tho, tetra) propylene glycol, 1,6-hexamethylene diol, etc. Examples of the alcohol include methyl alcohol, ethyl alcohol, Examples include n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, methyl cellosolve, ethyl cellosolve, and the like.

The polyurethane resin consisting of the above components is reacted at an equivalent ratio of incyanate/polyol + alcohol = about 0.8 to 1.1, and the equivalent ratio of polyol/alcohol is preferably about 1/9 to 1. It is. If the amount of alcohol used is too small, the molecular weight of the resulting polyurethane resin will increase, and the temperature dependence of viscosity will decrease;
If the amount of alcohol used is too large, the molecular weight of the polyurethane resin will become too low and the adhesiveness will deteriorate, which is not preferable. Therefore, the molecular weight of the polyurethane resin used in the present invention is preferably in the range of about 500 to 1,500.

In addition, the (meth)acrylate monomer used in the present invention may be one that is generally commercially available (for example, 2
-Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-
3-phenoxyprobyl (meth)acrylate, N-methylol (meth)acrylate, N,N'-diethylaminoethyl (meth)acrylate, (meth)acryloyloxyethyl monosuccinate, (meth)acryloyloxyethyl monophthalate, etc. Can be mentioned.

Further, for the purpose of improving adhesiveness, a polyfunctional (meth)acrylate monomer or the like may be used in combination within a range that does not impair the heat meltability of the adhesive layer.

The mixing ratio of the polyurethane resin and the (meth)acrylate monomer is such that the viscosity of the mixture is 400 c at 85°C.
It is preferable from the viewpoint of coating properties on porous supports and impregnation prevention properties to blend the composition so as to have a ps of not more than 1,200 cps at 70°C. The specific blending ratio varies depending on the molecular weight of the polyurethane resin used, the type of (meth)acrylate monomer, etc.
(Meth)acrylate monomer = 60-90/40-1
A weight ratio of 0 is preferred. In addition, in order to adjust the coating properties, volatile solvents such as methyl ethyl ketone and ethyl acetate may be added in small amounts to, for example, the solid content (polyurethane resin + (meth)
Acrylate monomer) may be blended in a range that does not leave 60% by weight of undropped particles (in this case, the coating properties of the adhesive on the thermoplastic resin film will be improved, and the film will not be deformed or wrinkled). (The adhesive can be applied thinly to the film surface.Of course, if the adhesive contains a small amount of solvent, it is preferable to evaporate the solvent before the adhesive is cured.)

The adhesive layer is formed by adding other additives and viscosity-adjusting solvents to the above adhesive as necessary, and applying multi-roll coating method, blade coating method, gravure coating method, knife coating method, reverse roll coating method. The layer may be formed by coating it on a porous support or a thermoplastic resin film by a method such as a spray coating method, an offset gravure coating method, a kiss coating method, etc. (The method for forming the layer is not particularly limited.

If the amount of coating is too large, the thermal perforation property during plate making will deteriorate, and if it is too small, problems will arise in adhesive strength, so a thickness of about 0.5 to 5 μm, for example, is suitable.

In addition, when the adhesive is solvent-free, the above coating is carried out at a temperature at which the adhesive has sufficient coating properties, for example, 80 to 90°C.
Although it is preferable to carry out the coating at an elevated temperature of about 0.degree. C., if the adhesive contains a small amount of solvent, it can be applied at room temperature.

After coating the radiation-curable adhesive, the adhesive layer becomes non-fluid when cooled, but the adhesive layer maintains a certain degree of adhesiveness or tackiness due to the presence of the monomer.
In this state, both the support and the film are laminated.

By curing the adhesive layer by irradiating radiation such as electron beams or ultraviolet rays from the thermoplastic resin film side or the porous support side during or after lamination, the two are firmly bonded, and the thermal mimeograph base paper of the present invention is obtained.

The radiation is preferably an electron beam, and the electron beam may be irradiated from any side of the laminate. Conventional techniques can be used as the irradiation device, such as Cockroft-Walton type, Bumpgraph type, and resonance transformation type. , insulated core transformer type, linear type, electrocurtain type, dynamidron type, high frequency type, etc. emitted from various electron beam accelerators.
An electron beam or the like having an energy of 1.000 KeV, preferably 100 to 300 KeV is used, and the irradiation dose is 1.
A dose on the order of ~5 Mrad is preferred.

The thermal mimeograph base paper of the present invention as described above has excellent plate-making properties, but when forming mimeograph holes by heating the thermoplastic resin film with a thermal head or other method, depending on the conditions, the thermal head may not heat up. There is a risk that the thermoplastic resin film may be destroyed by fusing to the plastic resin film, or that the positive original film may stick if a copying hole is formed by exposure through the positive original film.

In order to solve such problems, it is preferable to form a heat fusion prevention layer made of silicone oil, silicone resin, surfactant, or these and baingoo resin on the thermoplastic resin film.

The heat fusion prevention layer may be formed by dissolving or dispersing necessary materials in an organic solvent or water to prepare a coating solution, and applying this to the surface of the thermoplastic resin film by any method.

The thickness of the heat fusion prevention layer is preferably thin, since if it is too thick, the heat sensitivity will be reduced and the formation of perforations will be insufficient, and for example, a thickness of about 0.1 to 10 μm is preferable.

There is no particular limitation on the timing of forming this heat-fusion prevention layer, and it may be formed after or during the formation of the heat-sensitive mimeograph base paper of the invention, or may be formed on the original thermoplastic resin film.

(Example) Hereinafter, the present invention will be explained in more detail by giving Examples and Comparative Examples. In the text, parts or percentages are based on weight unless otherwise specified.

Example 1 Basis weight 10.5g/I, thickness 36.1μm, density 0.28
5g/c, 0.5 denier polyester fiber 30
% and 70% hemp was coated with the following electronic curing adhesive at 95°C by roll coating. Qg/lrf
After coating at a ratio of
The adhesive was cured by Mrad irradiation. Furthermore, apply 0.1g of the following thermal adhesion inhibitor on the polyester film surface in terms of solid content.
A thermal mimeograph base paper of the present invention was obtained by coating at a ratio of /a.

An electron beam curable adhesive was prepared by mixing 80 parts of an electron beam reactive polyurethane resin and 20 parts of an acrylic acid ester monomer (Aronix M5700, manufactured by Toagosei Co., Ltd.).

The above polyurethane resin was synthesized using di-n-butyltin dilaurylate-1 to m-benzophenone as a catalyst in the following formulation.

Toluene diisocyanate 3.00 mol 1.3-
Butanediol 0.80 mol 1,4-butanediol 0.20 mol n-butanol
1.50 mole isopropyl alcohol
1.60 mole methyl cellosolve 0.50
mol t-butanol 0.20 mol 2-
Hydroxyethyl acrylate 0.20 mol Saturated polyester resin (Byron 200, manufactured by Toyobo ■)
7-part amino-terminated polysiloxane resin (X-22-161B, Shin-Etsu Chemical ■
) 3 parts methyl ethyl ketone 540 parts cyclohexanone
60 parts Example 2 Basis weight 8, Og/G, thickness 40.0 μm, density 0.200
g/c, 0.1 denier 20%, 0.5 denier 2
A thermal mimeograph base paper of the present invention was obtained in the same manner as in Example 1 except that porous tissue paper made of 1% and 59% 2-denier polyester fibers was used.

Comparative Example 1 Commercially available Ricoh Report Master B4 type 900° The surface roughness (Ra) of the thermoplastic resin film surface of the base paper of the above Examples and Comparative Examples was measured using a three-dimensional roughness measuring instrument model 5E-3AK manufactured by Koita Seisakusho. As measured by Example 1,
The base paper of Example 2 has an average roughness of 1.2 μm and a maximum roughness (Rmax) of 9.2 μm, as shown in the first diagram, and the base paper of Example 2 has an average roughness of 0.8 μm, as shown in the second diagram. Maximum roughness (Rm
aX) was 7.2 μm, and the base paper of Comparative Example 1 had an average roughness of 1.5 μm and a maximum roughness (Rmax) of 13.5 μm, as shown in the third diagram.

In addition, when each base paper was plate-made and printed in photo mode using Recover Ribort 5S950, Example 1 was obtained.
The base paper had fewer white spots (and the image quality was significantly superior) compared to Comparative Example 1. In addition, the case of Example 2 was even better than that of Example 1.

(Effects) According to the present invention as described above, in the heat-sensitive mimeograph base paper,
By setting the surface roughness (Ra) of the thermoplastic resin film that lobes in a laminated state to 1.3 μm or less, it is possible to provide a thermal mimeograph base paper that has excellent perforation sensitivity and provides high-quality printed matter. .

Furthermore, in a preferred embodiment of the present invention, by forming the adhesive layer with a radiation-curable adhesive that does not substantially contain a solvent, the unevenness of the porous support can be well covered.
It has improved perforation sensitivity and excellent printing durability, and can be used as a thermal mimeograph base paper that provides high-quality printed matter.

[Brief explanation of drawings]

1 and 2 are diagrams showing the results of measuring the surface roughness of the base paper of the example, and FIG. 3 is a diagram showing the results of measuring the surface roughness of the base paper of the comparative example.

Claims (4)

[Claims] (1) In a heat-sensitive mimeograph base paper formed by laminating a thermoplastic resin film on one side of a porous support via an adhesive layer, the surface roughness (Ra) of the thermoplastic resin film in the laminated state is 1 A thermal mimeograph base paper characterized by having a particle size of .3 μm or less. (2) The thermal mimeograph base paper according to claim 1, which has a surface roughness of 1.0 μm or less. (3) The thermal mimeograph base paper according to claim 1, wherein the adhesive is a radiation-curable adhesive. (4) The thermal mimeograph base paper according to claim 1, wherein the adhesive is a radiation-curable adhesive comprising a polyurethane resin and a monofunctional and/or polyfunctional (meth)acrylate.