JPH0482792A - Manufacture of sheet for thermal stencil printing using multi-layer film - Google Patents

Abstract

PURPOSE:To enhance the productivity of a sheet and minimize the irregularities of curling properties attributed to the inferior size stability of the sheet by repeating the peeling-off of a layer consisting of a porous support laminated on both surfaces of a multi-layer film after said lamination process using a multi-layer film composed of thermal films laminated on both surfaces. CONSTITUTION:A support is laminated on one surface of (L3/L2/L1/L2/L3) which has a laminated film (L3) formed on both surfaces of a multi-tiered peel- off layer (L2/L1/L2), and this composition becomes (support/L3/L2/L1/L2/L3). Then the layer consisting of the thermal film laminated over the support is peeled off to prepare [(support/L3)+(L2/L1/L2/L3)] and then the support is laminated over the rear thermal film to prepare (L2/L1/L2/L3/support). After that, this layer is peeled off the multi-tiered peel-off layer to prepare [(L2/L1/L 2)+(L3/support)] and the peel-off process is repeated sequentially on each one surface after lamination. Subsequently, the tension when both surfaces are bonded together becomes further uniform so that the curling properties of the sheet are more uniform on the both surfaces.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a heat-sensitive stencil printing base paper (hereinafter referred to as "support") which is made by laminating a thermoplastic resin stretched film and an ink-permeable porous support (hereinafter referred to as "support"). The present invention relates to a method of manufacturing a base paper (hereinafter abbreviated as base paper), and particularly relates to a manufacturing method that improves the productivity of the base paper and the stability of physical properties of the base paper.

[Conventional technology]

Generally, in thermal stencil printing, a heat source such as a thermal head is used to thermally melt and perforate the base paper film in accordance with the characters and figures on the original, forming holes in the film, and then ink is applied from the support side of the base paper. Printing is performed by supplying clear ink and letting the ink ooze out from the holes.

Conventionally, in thermal stencil printing, a base paper is used that is made by bonding a stretched thermoplastic resin film, such as a polyester-based, vinylidene chloride-based, vinyl chloride-based, or polypropylene-based film, to a support such as natural fiber, nonwoven fabric, or gauze using an adhesive. are used (for example, JP-A-51-2513, JP-A-57-182495, JP-A-49-5933).
Publication No.).

In recent years, in this field, increasing the sensitivity of film has been considered in order to extend the life of thermal heads used in plate making.
As one means of achieving this, improvements have been made in the direction of reducing the film thickness. However, as the film becomes thinner, not only does the production of the film itself become more complicated, but also the base paper!
l! Problems during manufacturing such as wrinkles, sagging, distortion (unevenness in tension), and breaks became apparent, and the stability of quality and yield during manufacturing tended to decline.

In order to solve this problem, a method for producing base paper using a multilayer film including a heat-sensitive film layer, which is thicker than a heat-sensitive film alone, has been disclosed (for example, Japanese Patent Laid-Open No. 63-53097, Kaisho 64-173694
Publication No. 14092/1983, Japanese Patent Application Laid-Open No. 1986-14092
18689, JP-A-2-131994).

The aim is to improve the productivity of base paper,
JP-A No. 63-53097 discloses a two-layer structure consisting of a heat-sensitive film and a release layer, and a three-layer structure in which the heat-sensitive film is on both sides of the release layer.
Manufacturing method for laminating a support to a layered film, and JP-A-64-14092, JP-A-64-186
89@ publication, 3 on both sides of the heat-sensitive film or release layer.
A manufacturing method for bonding a support to a layered film has been disclosed. However, when using a three-layered film in which the heat-sensitive film is on both sides of a release layer, it is true that the productivity of the film itself and the Although the problem when bonding to the support can be solved, there is a problem in that the uniformity of the physical properties of the base paper produced on both sides, especially the variation in curling property due to poor dimensional stability, becomes noticeable. Ta. However, none of the above-mentioned publications have rigorously considered this point.

In addition, when using an ultraviolet (and electron beam) curing adhesive as an adhesive, when ultraviolet rays are irradiated from the support side, the ultraviolet rays are blocked by the support fibers, so the curing reaction occurs at the contact point between the support am and the film. does not progress sufficiently, resulting in poor adhesion. Therefore, it is common practice to irradiate ultraviolet rays from the film side, or to place heat-sensitive films on both sides of the release layer.
When using a film with a layered structure, in order to adhere the support on both sides, it is possible to irradiate from the film side the first time, but in the second time, because there is a support adhered on the back side, it is necessary to irradiate from the film side. was impossible.

[Problem to be solved by the invention]

Under these circumstances, the present invention provides a method for producing base paper that can improve the productivity of base paper and also significantly reduce variations in physical properties of base paper, particularly in curling properties caused by poor dimensional stability. It is something to do.

(Means for Solving the Problems) As a result of extensive research into the method of manufacturing base paper, the present inventors found that, compared to the conventional method of manufacturing base paper using a single layer of heat-sensitive film, the method of manufacturing base paper with heat-sensitive films on both sides When using a multilayer film, the productivity of the film itself is high, and by repeatedly bonding the multilayer film one side at a time and then peeling it off, it is possible to increase the productivity of both sides, compared to a process where supports are present on both sides at the same time. It becomes easier to control the tension more uniformly during lamination, which improves the curling properties (dimensional stability) of the base paper.
The inventors have discovered that the paper becomes uniform on both sides and that the productivity of the base paper is significantly improved, leading to the present invention.

That is, the present invention provides a co-stretched film in which heat-sensitive film layers (L3) are laminated by coextrusion on both sides of a multilayer release layer in which release layers (L2) containing a release agent are laminated on both sides of a single reinforcing layer (L1). Multilayer film (L3/L2/L1/L2/
After laminating the porous support to the heat-sensitive film (L3) on one side using L3), the laminated layer is peeled off, and then the porous support is laminated to the heat-sensitive film (L3) on the back side. The present invention provides a method for producing a base paper for heat-sensitive stencil printing, which comprises sequentially peeling off the laminated layer and the release layer after combining the laminated layers.

Next, the manufacturing method of the present invention will be explained with reference to the drawings.

FIG. 1 shows a schematic diagram of the method for manufacturing base paper of the present invention. Although FIG. 1 shows an example of a method in which adhesive is applied to the support side and laminated with the film when adhering the support and film, in the present invention, adhesive is applied to the support side or both the film side and the support side. It is also possible to apply adhesive to the parts and stack them together.

In the present invention, as shown in FIG.
2/L1/L2) formed on both sides of the heat-sensitive film (L3
) is laminated on one side of (L 3/L 2/Ll/L2/L3), and (Support/L 3/L 2
/L 1/L 2/L 3), and stack the support on the heat-sensitive film (L3) on the back side, that is, the other side (Support/L 3/L 2/L 1 /L 2/L 3). /Support), the laminated layer of the heat-sensitive film and the support is peeled off to form [(Support/L3) + (L2/L
l/L2/L3)], and then, the support is laminated on the heat-sensitive film on the back side to form (L2/Ll/L2/L3).
/ support), and peeling off the layer and the multilayer release layer,
It is characterized by ((L2/Ll/L2) + (L3/support)].

The important point here is to keep the tension as low as possible during lamination and to make the tension applied to the base paper formed on both sides uniform. This is because when extra tension is applied to the film on the support, that is, when the film is stretched on the support and stacked together to make a base paper, the film shrinks more than the film on the support. This is because the base paper has a strong tendency to curl on the sides, which tends to cause problems with running properties inside an automatic printing machine.

For example, as shown in FIG. 2, in a manufacturing method that involves the step of laminating supports on both sides,
/L 1 /L 2 /L 3 /Support) Since a laminate is formed, tension must be applied to the entire layer, and the tension itself increases, resulting in warpage and warping of each part during the lamination process. The difference in tension between the two ends becomes larger. Furthermore, since the relationship between the elongation and stress of each layer does not match completely at that time, it is extremely difficult to match the elongation of each layer, and it is difficult to control curling of the base paper.

In the simultaneous lamination shown in FIG. 2 (1), the tension on both sides during lamination tends to be uniform, but it is difficult to simultaneously control the support, multilayer film, and support.

In addition, in the sequential lamination shown in FIG.
(Support/L 3/L 2/L 1/L 2/L
3/Support), and the layer configurations during the first and second laminations are different (because they are different), it is difficult to control the tension, and it is difficult to maintain uniform curling of the base paper on both sides.

In contrast, in the present invention, the layer structure during lamination is (support/L 3 /L 2 /L 1 /L 2 /L3) in the first
So, the second layer is (L 2 / L 1 / L 2 / L 3 / support), and since the L3 layer is thinner than other layers, it is ignored in terms of strength. Body/L2
/Ll/L2), the second time can be considered as (L2/Ll/L2/support), and since both layers are uniform from the layer structure, it is easier to maintain uniformity in the curl of the base paper on both sides. It is.

Moreover, in the present invention, a reinforcing layer is provided at the center of the multilayer release layer to reduce the elongation of the heat-sensitive film when tension is applied, so that the absolute value of curl can be suppressed to a low level.

In addition, an important point is that when an ultraviolet (and electron beam) curable adhesive is used as the adhesive, in the manufacturing method of the present invention, it is possible to irradiate ultraviolet rays from the film side both in the first and second times. This makes it possible to produce uniform and strong base paper.

In the present invention, the degree of curl in the longitudinal direction of the base paper, which has a greater influence on mechanical suitability, was measured by the following method and used as an index of curlability.

That is, first, the obtained base paper was fixedly supported in a square frame measuring 100 mm in length and 100 mm in width so that the vertical and horizontal directions of the base paper were clearly defined, and a sample with cuts made in the base paper on the diagonal of the frame was placed on a film. It was left in a constant temperature bath at 50° C. for 24 hours with the side facing up. This sample was heated to 23°C.
After aging in a constant temperature room with 50% humidity for about 2 hours, the curl radius r (mm) in the vertical direction was determined, and from this,
Curl degree R was calculated according to the formula R=100/r. The smaller the degree of curl, the more preferable it is, but its permissible range is less than 5, and the smaller the variation in the value between base papers, the more preferable it is from the viewpoint of mechanical design.

The multilayer film used in the present invention is one in which heat-sensitive film layers are formed on both sides of a multilayer release layer by coextrusion and costretching.

First, the heat-sensitive film layer will be explained.

The thermosensitive film layer herein refers to a thermoplastic film having a thickness of 0.5 to 4 μm and having a tensile modulus of at least 75 kg/mm2, a heat shrinkage rate of at least 30%, and a heat shrinkage stress value of at least 75 g/m++2. It is made of polyester resin film.

Several layers are at least 75 kg/mm2, preferably 1
00 kg/mm2, more preferably 125 kg/m2
It is necessary to have a tensile modulus of elasticity of m2 or more. If the tensile modulus is less than 75 kg/mm2, the stiffness of the film becomes weak and the release layer is likely to be stretched or damaged when the release layer is peeled off, so that its use is restricted. The tensile modulus was measured in accordance with ASTM D8g2-67, and the stress at 2% elongation was converted to 100%.

Also, the several layers are at least 75 g/mm2, preferably 1
00~1200g/mm2, more preferably 150~
It is necessary to have a heat shrinkage stress value of 1000 g/mm". This heat shrinkage stress value
A strip of 0 mm width was sampled, set in a chuck equipped with a strain gauge with a gap of 50 mm between the chucks, and immersed in silicone oil heated to each set temperature to measure the stress generated. Set temperature is 10
Below 0℃, the value after 10 seconds after immersion, 100℃
If the value exceeds 5 seconds, the value was determined after 5 seconds, and the average value in the vertical and horizontal directions was used.

Further, the heat shrinkage stress value in the above range is 60 to 150°C,
Preferably 60-140°C, more preferably 70-13
It is desirable that the expression occurs in the 0°C range.

If the heating shrinkage stress value is less than 75 g/mm2, the opening during drilling is insufficient, and if the stress value is less than 1200 g/mm2,
If it exceeds m2, the pores will become too wide, the film will become distorted, and the resolution will tend to decrease. Furthermore, if this heat shrinkage stress value occurs below 60°C, there is a tendency for the dimensional stability of the film to decrease and the resolution to decrease due to the enlargement of the pores, while if it occurs above 150°C, the perforation sensitivity decreases. This is not desirable as it tends to decrease.

Furthermore, the heat shrinkage rate of several layers needs to be 30% or more, preferably 30 to 90%, more preferably 4
It is in the range of 0 to 80%. Note that this heat shrinkage rate is 5
A 0 mm square film was sampled, placed in a constant temperature bath set to the measurement temperature, and allowed to shrink freely for 10 minutes.The amount of shrinkage of the film was determined and expressed as a percentage of the original size. This heat shrinkage rate is preferably expressed at a measurement temperature of 60 to 170°C, more preferably 65 to 140°C. If the heat shrinkage rate is less than 30%, the holes will not be formed sufficiently during drilling, and if it exceeds 90%, the holes will tend to enlarge or the dimensional stability will decrease, which is not preferable. Furthermore, if this heat shrinkage rate occurs below 60°C, there is a tendency for the dimensional stability of the film to decrease and the resolution to decrease due to enlarged pores, while if it occurs above 170°C, the perforation sensitivity decreases. This is not desirable.

Furthermore, the thickness of several layers is 0.5-6 μm, preferably 1-6 μm.
It is more preferably 1.5 to 2.5 μm than 4 μm1. If this thickness is less than 0.5 μm, the strength is insufficient and the release layer tends to be easily damaged when peeling or drilling.
If it exceeds m, sensitivity tends to decrease and drilling becomes insufficient.

The thermoplastic polyester resin used here is, for example, a copolymerized polyester resin, in which one or both of the dicarboxylic acid component and the diol component that constitute the polyester are composed of two or more different components. It is something.

Specifically, when using different dicarboxylic acids,
Terephthalic acid and other dicarboxylic acids, such as aromatic dicarboxylic acids such as isophthalic acid and phthalic acid, aromatic dicarboxylic acids with substituents on the aromatic ring that do not contribute to the esterification reaction, or fatty acids such as succinic acid and adipic acid. Combinations of group dicarboxylic acids are used, and when different diol components are used, ethylene glycol and other diols, such as propyl glycol, diethylene glycol, 4-butanediol, 1.5-bentanediol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, polytetramethylene glycol, cyclohexane dimethanol, etc. are used as appropriate.

Preferred copolyester resins include, for example,
Mainly ethylene glycol as diol component, 1
．． 4-cyclohexane dimetatool up to 40 mol%,
It preferably contains 20 to 40 mol%, more preferably 25 to 35 mol%, and is polycondensed with terephthalic acid. Among these, especially
Crystallinity of the raw material resin that has been sufficiently annealed to reach an equilibrium state (by wide-angle X-ray method: Rotaflex RU-200B, manufactured by Rigaku Denki Co., Ltd., using a graphite monochromator, applied voltage 50 kV, applied current 16
0 mA, target Cu, measurement angle 2θ = 5 to 38°) of 30% or less, preferably 20%.
5% or less, more preferably 10% or less, particularly preferably 5%
% or less and is substantially amorphous. This particularly preferred resin is copolymerized using a mixture containing terephthalic acid as the main component as the dicarboxylic acid component and approximately 70 mol% of ethylene glycol and approximately 30 mol% of 4-cyclohexane dimetatool as the diol component. There is something I did.

Furthermore, other polymers and oligomers can be blended in several layers within the range that does not impair the necessary properties, and various additives such as antioxidants, heat stabilizers, plasticizers, etc.
A lubricant or the like can be added depending on the purpose.

Next, the multilayer release layer will be explained.

The multilayer release layer smoothly performs stretching film formation, which is difficult with a heat-sensitive film alone, and eliminates wrinkles and wrinkles when laminated with a support.
It is used for the purpose of preventing problems such as stretching and tearing, and furthermore, for bleeding transfer of necessary additive components to the heat-sensitive film. In particular, the present invention aims at maintaining tension during bonding with a support (avoiding excessive tension from being applied to the heat-sensitive film layer as much as possible).

The multilayer release layer has a multilayer structure (L
2/L 1/L 2), the reinforcing layer is used especially for the purpose of improving the elastic modulus of the multilayer release layer and reducing the elongation during lamination, and the release layer is It is used for the purpose of stably retaining a release agent in order to improve the stretchability of a multilayer film and improve the peelability from a heat-sensitive film.

When each layer is used alone, the reinforcing layer alone tends to result in poor stretchability, and the release layer alone tends to cause the multilayer film to stretch easily when tension is applied. Therefore, their use alone is limited, and the manufacturing method of the present invention can only be satisfied by forming them into a multilayer structure.

The reinforcing layer is made of a propylene polymer with a Vicat softening point of at least 100°C and a low flexural modulus (both 75 kg/square).The reinforcing layer has a Vicat softening point of at least 100°C, preferably The temperature is 110°C, more preferably 120°C, and the lower limit thereof is limited by heat resistance.Furthermore, the flexural modulus is at least 75 kg/mm2, preferably 85 kg/mm2, and this lower limit is set in combination with the release agent layer. (Measurement method is based on ASDM D 790).Propylene polymers here include both homotype and copolymer types, and furthermore, polybutene-1
The polymers of the system may be mixed in an amount of 40% by weight or less.

In addition, the thickness of several layers is not particularly limited, but is generally 0.2
-20 μm, preferably 0.5-15 μm, more preferably 1-10 μm. This lower limit is determined by the ability to maintain tension during bonding, as well as the strength of the multilayer release layer as a whole.
It is limited by releasability, handleability, stretchability, etc., and its upper limit is limited by stretchability.

In addition, a multilayer film (L 3 / L 2 / L 3 / L 2 / L 3) in which a thermosensitive film layer is further formed as a reinforcing layer
In that case, the layer thickness is 0.5 to 4 μm.
1 preferably 0.5 to 3 μm 1 more preferably 0.5 to 3 μm
The range is 2 μm. This lower limit is also limited by the tension retention during bonding, as well as the strength, peelability, handleability, stretchability, etc. of the multilayer release layer as a whole, and the upper limit is limited by the stretchability.

Next, as for the release layer, several layers are used for the purpose of improving the stretchability of the multilayer film, and the Vicat softening point (VSP)
is below 100℃, and the crystallinity (according to DSC method) is 60
% or less of ethylene or butene-1 polymer, or
It consists of a copolymer thereof, or a composition consisting mainly of the above resin and a mixture thereof with other resins. Among these, ethylene polymers and ethylene copolymers are preferred, and compositions containing the latter as the main component and 5 to 50% by weight of ethylene-α/olefin copolymer elastomer added thereto, or compositions containing these, The composition further contains a polypropylene polymer in an amount of 5 to 50% by weight, based on 100 parts by weight of both of the above.

As a preferable example, linear low-density polyethylene or ethylene-vinyl acetate copolymer (with a vinyl acetate group content of 5 to 25% by weight) is used as the ethylene polymer or copolymer. Examples include a composition in which 5 to 30 weight percent of an α-olefin elastomer is added, and a mixed composition in which 5 to 30 weight percent of a polypropylene polymer is added to 100 parts by weight. The feature of several layers is that the layer itself not only has good stretchability, but also has the effect of imparting good stretchability to the adjacent layer, and in addition has the effect of preventing necking stretching.

In addition, the thickness of several layers is 3 to 100 μm per layer, preferably 5 to 50 μm, more preferably 5 to 20 μm.
It is m. The lower limit is determined by releasability, stretchability, and transferability of additives, and the upper limit is determined by coextrudability and economic efficiency.

Furthermore, the release layer is characterized by containing a release agent in several layers,
It is possible to significantly improve the peelability of the heat-sensitive films on both sides. As the additive, esters of fatty acids and high-value alcohols, polyoxyethylene alkyl ethers, high-grade alcohols, waxes, etc. are preferably used, and a mixture of oleic acid monocrycerite and polyglycerin monooleate is particularly suitable. , the ratio is 50
=50% by weight shows a remarkable effect on high-speed releasability.

The amount of the additive added is 0.2 to 5% by weight, preferably 0.5% by weight, based on the total weight of the resin constituting the release layer.
~3% by weight.

Furthermore, the support that constitutes the base paper used in the present invention is
7. A porous material such as thin paper or nonwoven fabric made from natural fibers, recycled fibers, synthetic fibers, etc. alone or a mixture of these fibers, which allows printing ink to pass through and does not substantially undergo thermal deformation during plate making. Yes, basis weight 4-20g/rr? Those are preferably used. Preferably it is 6 to 15 g/rr1', more preferably 8 to 12 g/rr1'.

In addition, as adhesives for bonding the film and the support, various types of adhesives such as commonly known solvent type, hot melt type, emulsion latex type, reaction curing type, ultraviolet ray and electron beam curing type, etc. can be used for bonding the film and support. It can be used under conditions that do not impede the perforability of the ink and the permeability of the ink. Furthermore, the application of the adhesive is usually carried out by a known method, and the adhesive is applied on the film side,
What is necessary is just to apply an adhesive to the support side or both, and to attach them together. The amount of adhesive is 0.1 to 5 g/rr, preferably 0.5 to 3 g/rr, more preferably 0.5 to 2
It is g/go.

〔Effect of the invention〕

In the manufacturing method of the base paper of the present invention, a multilayer film with heat-sensitive films on both sides is used, so the productivity of the film itself is high. Because the tension during lamination becomes more uniform, the curling properties of the base paper become more uniform on both sides, and since the reinforcing layer is provided at the center of the multilayer release layer, the elastic modulus of the multilayer film improves and elongation is reduced. This has the effect of suppressing the curling of the base paper to a low level.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to these examples.

Example 1 The heat-sensitive layer (L3) was obtained from terephthalic acid and a mixed diol consisting of 30 mol% of ■,4-cyclohexanedimethanol and 70 mol% of ethylene glycol, with a Vicat softening point of 82°C, density I, and 27 g. /cm3, a substantially amorphous copolyester having an intrinsic viscosity of 0.75, and as the release layer (L2), (A) the content of vinyl acetate units is 10% by weight, and the melt index is 1.0.
, 70 parts by weight of ethylene-vinyl acetate copolymer with Vicat softening point of 81°C and melting point of 95°C, (B) density of 0.88 g/
cm3, melt index 0.44, amorphous ethylene-α olefin polymer elastomer 15-weight total with Vicat softening point 40°C, and (C) density 0.90 g/cm”
, Melt 70-L/-) 7, Vicat Softening Point 138℃
, a mixture with a flexural modulus of elasticity of 110 kg/mm2, a melting point of 143°C, and a Vicat softening point of 72°C consisting of 15 parts by weight of crystalline polypropylene randomly copolymerized with 4% by weight of ethylene, and oleic acid monoglyceride and diglycerin monoglyceride as release agents. A composition containing oleate in a weight ratio of 2:1 is used in an amount of 2% by weight based on the total weight of the composition, and further, as a reinforcing layer (L1), the above-mentioned crystalline polypropylene and Using the same material, melt each in an extruder, and blow the annular multilayer die to determine the composition of each layer (L
After extruding to a ratio of 3/L 2/L 1 /L 2/L 3), it was rapidly cooled and solidified using a refrigerant to obtain a tube-shaped original fabric.

Next, this original fabric was heated to 95°C and simultaneously biaxially stretched in a bubble shape in an atmosphere of 90°C so that the stretching ratio was 5.0 times in the vertical direction and 5.0 times in the horizontal direction. A film was obtained by cooling with air at ℃. Both ends of the obtained film were slit, and two films were wound up into a roll using a winding machine. This multilayer film (L 3/L 2/L 1
/L 2/L 3) The thickness of each layer is 2/8/2/8
/2 μm.

Furthermore, the two multilayer films were divided into two film rolls each having a width of 900 mm using a winder and used for producing base paper.

Meanwhile, the adhesive was formulated as follows. Ethylene glycol diglycidyl ether (Nagase Kasei Kogyo ■, Bunacol EX-810) was used as the epoxy compound, and polyamide amine (Sansho Kagaku Kogyo ■, Sanmide 300) was used as the polyamine resin, and the weight ratio of each component was adjusted to epoxy compound:polyamine resin. =17+83 and dissolved in isopropyl alcohol.

First, the support is 1i 110.5g/d, thickness 3
The first unwinding machine (
After applying the adhesive solution to this thin paper using a gravure coater so that the adhesive coating amount is 1.5 g/g, the thin paper mentioned above is fed out from the second unwinding machine (U2). The stacked multilayer film is passed through a drying oven set at 50°C to evaporate the solvent, and then the laminated support and thermosensitive film (base paper intermediate 1) are rolled up into a first roll. While winding with machine (W1),
The other multilayer release layer/thermosensitive film layer was removed.

Furthermore, in a continuous state, on the heat-sensitive film side of this peeled layer, after being unwound from the third unwinding machine (U3), a thin paper having the same physical properties as above and coated with the above adhesive in the same manner is superimposed, After laminating in the same manner, the multilayer release layer is peeled off while winding up the laminated support and heat-sensitive film (base paper intermediate 2) with a second winder (W2),
Finally, the multilayer release layer was wound up with a third winder (W3).

Further, this base paper intermediate was aged at 35° C. for 48 hours to complete adhesion.

Using the obtained base paper intermediates 1 and 2, silion oil was added at 0.05 g/rr under the same conditions. This was applied to form a heat-fusible overcoat layer to obtain final base papers 1 and 2. The curling properties of the obtained base paper were 100m, 1000m,
When measuring at 6 points in the width direction at 2000 m, the results were as follows.

100m looOm 2000
m base paper 1 4,000.2 3.9±0.3 3.
9±0.2 Base paper 23.9±0.2 4.0±0.2
4.0±0.3 Both base papers 1 and 2 showed very good results with little variation in curl.

Furthermore, both of the obtained base papers 1 and 2 were plate-printed using a fully automatic digital stencil printing machine (Puriport 58930, manufactured by Rino) using facsimile test chart No. 2 (manufactured by the Institute of Image Electronics Engineers of Japan) as a manuscript. Clear prints were obtained, and no major changes were observed in the images even after printing more than 5,000 sheets.

Example 2 Component (A) of the release layer of Example 1 had a density of 0.89,
A similar multilayer film was prepared using the same equipment as in Example 1 using 70 parts by weight of an ethylene-α-olefin copolymer containing 15 wt% of α-olefin with 1 butene and a crystallinity of 30% (according to DSC method). Obtained. The same support as in Example 1,
A base paper of 1°2 was obtained using the same equipment.

The curling properties of the obtained base paper were 100m and 1000m.
.

Measurements were taken at 6 points in the width direction at 2000 m, and the results were as follows.

Loom 1000m 2000
m base paper 1 3.2±0.2 3J±0.2 3.1
±0.2 Base paper 23.4±0.1 3.2±0.2
3.0±0.2 Base paper 1.2 showed very good results with small variations in curl.

As with Example 1, no problems occurred with base paper 1.2 when evaluated using a fully automatic digital printing machine.

Example 3 This experiment was carried out using the same film and support as in Example 1, and the same equipment, but changing the adhesive to an ultraviolet curable adhesive. As an ultraviolet curing component, )・rimethylolpropane triacrylate (Osaka Organic Chemical Industry ■, Viscoat #29
5) 90% of 2-methyl-2- as photoinitiator
Morpholino(4-thiomethylphenyl)propane-1-
On (Ciba Geigy, Irgacure 907) 10% by weight was mixed and adjusted. Using this adhesive, the application rate is 1
．． 5 g/m', and instead of the drying oven in Example 1, a water-cooled UV lamp (Toshiba Denzai ■, 80 W) was used.
Using a H5600L/81N 7 /cm lamp, ultraviolet rays were irradiated from the film side at a light intensity of 15 mJ/cJ to obtain base paper intermediates 1 and 2.

Using the obtained base paper intermediates 1 and 2, 0.05 g/rr of silicone oil was applied under the same conditions. This was applied to form a heat-fusible overcoat layer to obtain the final base paper 1.2.

The curling properties of the obtained base paper were 100m and 1000m.
.

When measuring at 6 points in the width direction at 2000 m, the results were as follows.

room 1000m 2000m Base paper 1 3.8±0.3 3.9±0.1 3.7±
0.3 base paper 24.0±0.2 4.0±0.2 3
．． 9±0.3 Both base papers 1 and 2 showed very good results with little variation in curl.

Further, in the same way as in Example 1, no problem occurred with base paper 1.2 when evaluated using a fully automatic digital printing machine.

Comparative Example 1 First, the same thin paper as in Example 1, which is a support, is unwound from the first unwinding machine (U1), and the adhesive is applied to ff11.
After applying an adhesive solution to this thin paper using a gravure coater so as to give an adhesive solution of 5 g/rrr, it was superimposed on the same multilayer film as in Example 1, which was fed out from the second unwinder (U2), and then continuously coated. In this state, after unwinding from the third unwinding machine (U3), thin paper having the same physical properties as above and coated with the same adhesive as above is placed on the back side of the thermosensitive film, and laminated in the same manner. The combined state was passed through a drying oven set at 50° C. to evaporate and dry the solvent on both sides. This laminated support and heat-sensitive film (base paper intermediate 1) are wound up by a first winder (W1), and the laminated support and heat-sensitive film (base paper intermediate 2) on the rough back side are wound up in a second winder. The multilayer release layer was peeled off while being wound up with a winder (W2), and after R, the multilayer release layer was wound up with a third winder (W3).

Roughly, this base paper intermediate was aged at 35° C. for 48 hours to complete adhesion.

Using the obtained base paper intermediates 1 and 2, 0.05 g/g of silicone oil was applied under the same conditions to form a heat-fusible overcoat layer to obtain final base papers 1 and 2. The curling properties of the obtained base paper were 100m, 1000m, 200m.
When measuring at 6 points in the width direction at 0 m, the results were as follows.

100m 1000m 2000m Base paper 1 5.2±0.3 5.4±0.4 5.3 Staff 4 Base paper 24. O±0.4 3.8±0.3 3.
7±0.3 Compared to the example, base paper 1 had a greater degree of curl than base paper 2, making it impossible to obtain a base paper that was uniform on both sides, and problems tended to occur in conveyance in a fully automatic digital printing machine.

Comparative Example 2 First, the same thin paper as in Example 1, which is a support, is fed out from the first unwinding machine (U1), and the amount of the ultraviolet curable adhesive used in Example 3 is 1.59/end. After coating this thin paper using a gravure coater as shown in FIG. After being unwound from the third unwinding machine (U3) in a rough and continuous state, a thin paper having the same properties as above and coated with the same adhesive as above is superimposed on the heat-sensitive film side on the back side. , similarly 1
After laminating by irradiating ultraviolet rays from the side where the supports are laminated for the second time, the laminated supports and the heat-sensitive film (base paper intermediate 1
) is wound up with a first winding machine (W1), and the multilayer release layer is further wound up with a second winding machine (W2) while winding up the laminated support and the heat-sensitive film (base paper intermediate 2) on the back side with a second winding machine (W2). Finally, the multi-layer release layer is removed by a third winder (W
3).

Using the obtained base paper intermediates 1 and 2, 0.05 g/rrr of silicone oil was applied under the same conditions to form a heat-fusible overcoat layer to obtain final base papers 1 and 2.

The curling properties of the obtained base paper were 100 m and 1000 m.

When measuring at 6 points in the width direction at 2000 m, the results were as follows.

100m 1000m 2000
m base paper 1 5.4±0.5 5.2±0.6 5.
2±0.5 Base paper 23.6±0.4 3.7±0.4
3.6±0.4 Compared to Example 3, the degree of curl of base paper 1 was greater than that of base paper 2, and a base paper that was uniform on both sides could not be obtained, and problems were likely to occur in conveyance properties in a fully automatic digital printing machine.

The base paper 1 obtained with a fully automatic digital printing machine is 5000
Although it was possible to print 3,000 copies of the obtained base paper 2, distortion occurred in the image. This is considered to be because the adhesive was not sufficiently cured because the second UV irradiation was performed from the side of the support that was bonded the first time.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the manufacturing process of the base paper for thermal stencil printing of the present invention. FIGS. 2(1) and 2(2) are diagrams schematically showing the manufacturing process of a comparative example. 1, 1': Porous support unwinding section 2: Multilayer film unwinding section 3, 3': Base paper winding section 4: Multilayer release layer winding section 5, 5': Adhesive coating section

Claims (1)

[Claims] 1. A co-stretched multilayer film in which a thermosensitive film layer (L3) is laminated by coextrusion on both sides of a multilayer release layer in which a release layer (L2) containing a release agent is laminated on both sides of a reinforcing layer (L1). L3/L2/L1/L2/L3), a porous support is laminated on one side of the heat-sensitive film (L3), and then the laminated layer of the heat-sensitive film and the porous support is peeled off. Then, after laminating a porous support to the heat-sensitive film (L3) on the back side, a layer in which the heat-sensitive film and porous support are laminated and a release layer are sequentially peeled off. Method of manufacturing base paper.