JPH05221176A - Original paper for heat sensitive stencil printing and manufacture for plate therefor - Google Patents

Abstract

PURPOSE:To improve the stability with time of a heat-sensitive original paper for stencil printing by means of the flash light, by bonding a thermoplastic stretched film of a predetermined thickness and satisfying a predetermined formula with a screen fabric of synthetic fiber of a predetermined mesh in a manner to hold a specific bonding strength. CONSTITUTION:A fabric screen of synthetic fibers of 50-300 mesh (for example, screen fabric of polyester fibers) is bonded with a stretched film of thermoplastic resin of 1-15mum thickness and satisfying the formula I in a manner to hold the bonding strength of 5-200g/25mm width. It is to be noted that Tg in the formula I is a glass transition point deg.C, and Xc, mp represent the cristallinity (0<Xc<1) and a melting point deg.C, respectively. The thermoplastic resin is copolymerized polyester or the like, and bonded to assume a predetermined strength (5-200g/25mm width) by means of an adhesive of vinyl acetate, etc. At the same time, fatty acid amide or the like is applied onto the surface of the film to prevent the fusion and adhesion with the printed document.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil printing base paper suitable for plate making by flash light such as a xenon lamp or a flash bulb and a plate making method thereof, and particularly, the printing quality is beautiful and the physical properties of the base paper are the same as those of conventional base paper. A heat-sensitive stencil printing base paper that does not change.

[0002]

2. Description of the Related Art A plate making method using flash light is disclosed in Japanese Patent Publication No. 41-7623 and Japanese Patent Publication No. 52-4969. As the heat-sensitive stencil printing base paper used for these plate making, those obtained by adhering Japanese paper or polyester cloth to a vinyl chloride-vinylidene chloride copolymer film have been used. However, the base paper is poor in stability over time, and the base paper may be warped or twisted due to the shrinkage of the film. Further, the film has a defect that the perforation performance is deteriorated due to crystallization progressing with time.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-sensitive stencil printing base paper which is capable of plate making with flash light such as a xenon lamp or a flash bulb and is excellent in stability over time, and an optimum plate making method thereof. And

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on a heat-sensitive stencil printing base paper which can satisfy perforation sensitivity and stability over time, and as a result, found that the above-mentioned problems can be solved. That is, the thickness of the thermoplastic resin is 1 to 15 μm.
In a stretched film satisfying the following formula (1) in m, 50 to 3
00 mesh synthetic fiber gauze with an adhesive strength of 5-200g
As a heat-sensitive stencil printing base paper laminated to a / 25 mm width, and an optimum plate making method of the base paper, the above base paper is 2.0 J / c.
It is a method of making a heat-sensitive stencil printing base paper in which a perforation is performed with a flash light having an energy of m ² or less.

50 ≦ Tg (1-Xc) + mp · Xc ≦ 140 (1) (where Tg (° C.) is the glass transition point, Xc is the crystallinity (0 ≦ Xc ≦ 1), mp (° C.) Is a melting point.) The film for heat-sensitive stencil printing base paper (hereinafter, simply referred to as a film) used in the present invention is made of a thermoplastic resin and has the above-mentioned (1)
It is a film that satisfies the formula. Equation (1) is an equation showing the response of the film to temperature, and Tg (1-Xc) +
In the case of mp · Xc <50, the dimensional stability of the film near room temperature such as stability over time becomes poor, which is not preferable.
In the case of g (1-Xc) + mp · Xc> 140, the heat-sensitive perforation sensitivity is low, which is not preferable. Preferably, the value is 6
0 to 115, more preferably 65 to 100.

Here, describing each of Tg, Xc, and mp, the Tg of the thermoplastic resin constituting the film is 6
When the temperature is 0 ° C. or higher, more preferably 70 ° C. or higher, the dimensional stability near room temperature and the stability of the perforation performance tend to be improved, which is preferable. Further, from the viewpoint of heat-sensitive perforation sensitivity, Xc when the resin is formed into a film is preferably 30% or less. The crystallinity referred to here is the crystallinity when formed into a film, and the measuring method is a wide-angle X-ray method or a density method. For simplification, it may be obtained from the melting peak area of the crystal in the DSC measurement. Such a resin has a slow crystallization rate when it is sufficiently annealed in a resin state and has a saturated crystallinity of 30% or less, and even when the saturated crystallinity exceeds 30%, it is processed into a film. May also have a crystallinity of 30% or less. The former is preferred. The heat of fusion (by DSC) of the film is preferably 10 cal / g or less, more preferably 6 cal / g or less, still more preferably 3 cal / g or less.

From the viewpoint of perforation sensitivity, mp is preferably 300 ° C. or lower, more preferably 260 ° C. or lower. Specifically, polyethylene-based polymers (including ethylene-vinyl alcohol-based polymers), polyolefins such as polypropylene-based polymers, polyesters (preferably copolyesters), polyamides (preferably copolyamides), styrenes Examples thereof include a polymer, an acrylic acid derivative resin, an acnylonitrile resin, and a copolycarbonate resin.

Copolymerized polyesters and copolyamides are preferable, and copolyesters are particularly preferable. Explaining in detail with respect to the monomers constituting the polymer, the acid component is selected from terephthalic acid and its isomers, their derivatives, dicarboxylic acids having a naphthalene structure, aliphatic dicarboxylic acids such as adipic acid, and their derivatives. One or more of the following, and then ethylene glycol and its derivatives (diethylene glycol, triethylene glycol, polyethylene glycol, etc.) as an alcohol component,
From alkylene glycols (trimethylene glycol, tetramethylene glycol, hexamethylene glycol, etc.), aliphatic saturated cyclic glycols (cyclohexanediol, cyclohexanedimethanol, cyclohexanealkyldiols, etc.), aromatic rings such as diols having a bisphenol nucleus It is a polyester obtained by copolymerizing one or more selected ones. The preferred combination is terephthalic acid (40 mol.% Or less of isophthalic acid, phthalic acid, adipic acid or the like may be copolymerized) as an acid component. As the alcohol component, ethylene glycol, diethylene glycol, cyclohexanedimethanol, bisphenol A, and the like are freely combined components and components mixed at a ratio are polymerized. If one example is shown, terephthalic acid as an acid component,
Ethylene glycol 65-75 as alcohol component
mol. %, Cyclohexanedimethanol 25-35
mol. % Of polyester.

Further, thermoplastic resins such as other polyesters, polyolefins, polyamides and EVOH are blended with the above resins, inorganic particles such as silica, carbon, calcium carbonate, mica and talc, and styrene or acrylic cross-linking resins. Particles, resin particles such as silicone resin particles, copper,
Metal powders such as zinc and titanium, and pigments and dyes may be added.

The thickness of the resin film is preferably 1 to 15 μm, and when it is thinner than 1 μm, it is difficult to laminate a synthetic fiber gauze and a film in a single layer state which are to be processed later, and heat fusion with a printing original is carried out during plate making. It is easy to tear due to factors such as Again 15
If it is thicker than μm, the perforation sensitivity decreases. The heat-sensitive film may have one layer, or may have a multi-layered structure of two layers, three layers or more.
In that case, at least one surface layer needs to be the film described in the present invention.

Further, since the above film has a sensitivity to effectively perforate even at low energy and can be used even at over energy, the heat shrinkage ratio (X) at 100 ° C. is 5 to 70% at the same temperature. The heat shrinkage stress (Y) at 50 to 600 g / mm ² is preferable. More preferably, X = 10 to 65%, Y = 200 to 400 g / m
This is the case of m.

In the production of the above-mentioned film, in order to effectively impart a shrinkage component to the ultrathin film at a low temperature, it is preferable to stretch the layer rather than a single layer (hereinafter referred to as a reinforcing layer). (Referred to as “calling”) and stretching in a multilayer form. The layer structure at that time is M / B, M / B / M, B / M / B, M / B, where M is the thermosensitive film layer and B is the reinforcing layer.
/ M / B / M ..., (where M and B are multi-layered layers having a free layer structure, for example, B / B ', B / B' /
It may be B, B ′ / B / B ′ or the like. ). Here, the reinforcing layer contains a release agent (surfactant such as polyoxyethylene alkyl ether, glycerin fatty acid ester, dimethyl silicone oil, modified silicone oil such as amino-modified, ether-modified, mercapto-modified, epoxy-modified, fatty acid amide, etc.) Vicat softening point (VSP; AST
According to MD-1525, load 1kg, temperature rising rate 2 ° C /
A layer mainly composed of a thermoplastic resin having a temperature of 110 ° C. or less is preferable. The stretching conditions are preferably as low as possible in order to impart a shrinkage component at a low temperature, and stretching at a high ratio is preferred. Further, it is preferable to selectively subject B to a crosslinking treatment to widen the stretching latitude. Specifically, from the polyester resin VSP + 15 ° C. in the film to the same VSP + 4
At a temperature of 5 ° C., preferably in at least one axial direction, preferably 2
Stretching in the axial direction is preferable.

The film stretched by the above method is heat-treated depending on the purpose. The heat treatment method includes a method of pressing with a hot roll (embossing may be performed at this time), a case of performing heat treatment while restraining or relaxing the film in an oven, and any method may be used. The formed multilayer film, such as M / B / M, is subjected to secondary processing as it is (eg, coating, lamination with a support, etc.)
Or may be peeled off and subjected to secondary processing with an M layer single layer film.

Next, the porous support to be laminated with the film of the present invention is capable of transmitting printing ink, does not deform even under heat shrinking conditions in which the film is perforated, and does not warp or twist the base paper over time. Further, a synthetic fiber mesh of 300 to 50 mesh, in which fibers are not conspicuous when printed, can be mentioned. It is preferably from 250 to 100 mesh. As the material, polyester fibers are preferably used, but vinylon fibers, urethane fibers, or inorganic fibers may be used alone or in combination.

Examples of adhesives used to bond the heat-sensitive film and synthetic fiber gauze are vinyl acetate adhesives, epoxy adhesives, acrylic adhesives, ultraviolet curable adhesives, electron beams. A curable adhesive, a hot melt resin, etc. may be mentioned. Also, the adhesion method is a wet method,
Any dry method may be used, and a gauze obtained by coating the above gauze with a hot melt resin or knitting fibers containing the same may be used.

However, in this case, the adhesive strength is 5 to 200 g.
It must be / 25 mm wide. Adhesive strength is 5g / 25
When the width is smaller than the mm width, the film and the support are likely to be peeled off at the time of peeling from the printing original after plate making, or peeled off at the time of printing. If the adhesive strength is stronger than the width of 200 g / 25 mm, the holes will not be widened during perforation by the flash and the printed matter will be unclear.

In order to prevent the film surface from fusing with the printed original, a fatty acid amide, a surfactant (glycerin ester, polyoxyethylene alkyl ether, etc.),
You may apply fluororesin, silicone oil, etc. Preferably alkyl modified, amino modified, mercapto modified,
It is a modified silicone oil such as epoxy modified or alcohol modified.

Next, a preferred method for making a heat-sensitive stencil printing base paper obtained by laminating the above film and gauze is 2.0 J /
This is a method for making a heat-sensitive stencil printing base paper in which a flash light having an energy of cm ² or less is used for perforation. More preferably 1-2
J / cm ² . Also, the flash flash time is 10 ms
ec or less is preferable, and more preferably 5 msec or less. Energy higher than 2.5 J / cm ² or 10 m
When the plate is made with a flash time longer than sec, the printed characters tend to be thick and the resolution tends to decrease. In addition, when a flash valve or the like is used to make a plate over the printed document, the perforated portion is fused to the printed document and is unlikely to come off. The film may be torn in some cases.

[0019]

EXAMPLES First, the measuring method will be described. (1) Crystallinity (wide-angle X-ray method) A film sample was crushed while being cooled with liquid nitrogen,
Rigaku Denki's Rotaflex RU-2
Using 00B (using a graphite monochromator), the measurement was performed at an acceleration voltage of 50 KV, a tube current of 160 mA (target: Cu), and 2θ of 5 to 36 °.
Further, the density of the sample whose crystallinity has been clarified by the above method may be measured (according to JIS K-7112-D method) to prepare a calibration curve, and thereafter the crystallinity may be determined by density measurement. Further, in some cases, the heat of fusion may be determined from the DSC curve of the sample whose crystallinity has been clarified by the wide-angle X-ray method, and the crystallinity of the unknown sample may be determined from this value.

(2) Heat Shrinkage (X) A 50 mm square film sample was left for 10 minutes in a hot air circulation thermostatic chamber set at 100 ° C. in a freely shrinkable state, and the shrinkage amount of the film was calculated. It is shown as a percentage of the value divided by the dimension. However, in the case of biaxial stretching, the average of length and width is shown, and in the case of uniaxial stretching, the value is shown only in the stretching direction.

(3) Heat shrinkage stress (Y) Silicone oil heat-shrinked at 100 ° C. by cutting a film sample into a strip shape having a width of 20 mm and a length of 200 mm, sandwiching it into a chuck with a strain gauge (100 mm between chucks). It was obtained by immersing the sample in water and detecting the generated stress. The measured values were taken 10 seconds after the immersion, and shown as an average in the longitudinal and transverse directions (however, in the case of uniaxial stretching, only the stretching direction).

(4) Perforation sensitivity Print Gokko PG-10 (plate-making energy: about 3 J / cm ² ) manufactured by Ideal Science Co., Ltd. and a lamp house of the apparatus were modified so that plate-making could be carried out from two conventional flash bulbs to one plate. Each of the heat-sensitive stencil printing base papers was prepared by using. The evaluation is “condition 1” before the PG-10 modification and “condition 2” after the modification, and is “⊚” when the print density (OD) is 1.0 or more and the printed matter is clear, and the OD is 1.0. If the line is thick and the image quality is slightly inferior, the result is "○", the OD is 0.5 or more and less than 1.0, and the image quality is inferior is "△", the OD is less than 0.5, and the printed matter is "X" when it is almost impossible to determine
And

(5) Stability over time Each heat-sensitive stencil printing base paper was allowed to stand at 50 ° C. for 3 days, and the warped and twisted states of the base paper were observed. Those with no change in appearance are marked with "◎", those that are slightly warped or twisted but have no practical problems are marked with "○", and those that have been warped or twisted but have been manageable are marked with "△", The product which was unusable due to twisting and the product which was peeled off was defined as "x".

(6) Peel strength The adhesive strength between the film and the porous support is JIS K68.
According to No. 54, the film and the porous support were reinforced with cellophane on both surfaces and a T-type peel test was conducted.

[0025]

[Examples 1 to 4 and Comparative Examples 1 and 2] Films used in Examples and Comparative Examples are shown below. Film 1: 100 mol. Of terephthalic acid as an acid component.
%, Ethylene glycol 70mo as alcohol component
l. %, 1,4-cyclohexanedimethanol 30mo
l. %, A thermoplastic polyester resin film having Tg = 81 ° C. and Xc = 0%. Tg (1-Xc) + mp ・
Xc = 81 ° C. (Film thickness: 2 μm, X = 60%,
Y = 300 g / mm ² ) Film 2: The acid component is terephthalic acid 85 mol. %, Isophthalic acid 15 mol. %, Ethylene glycol 98 mol. %, Diethylene glycol 2 mol. % Mp: 235 ° C., Tg = 70 ° C., Xc
= 20% copolyester resin film. Tg (1
−Xc) + mp · Xc = 103 ° C. (X = 7%, Y = 3
30 g / mm ² ) Film 3: Tg = 70 ° C., mp = 265 ° C., Xc = 4
0% polyethylene terephthalate film. Tg (1
−Xc) + mp · Xc = 148 ° C. (Film thickness: 2
μm, X = 0%, Y = 0 g / mm ² ) Film 4: Terephthalic acid and adipic acid as acid components, ethylene glycol and diethylene glycol as glycol components, Tg = 40 ° C., mP = 18
A polyester resin film of 0 ° C. and Xc = 25%. Tg
(1-Xc) + mp · Xc = 75 ° C. (Film thickness:
2 μm, X = 50%, Y = 150 g / m m ² ) Film 5: Tg = −10 ° C., mp = 160 ° C.,
Vinyl chloride-vinylidene chloride copolymer film containing Xc = 30% of plasticizer. Tg (1-Xc) + mp · Xc = 4
1 ° C. (Film thickness: 7 μm, X = 20%, Y = 18
0 g / mm ² ) Film 6: Ethylene content 2.7% by weight, Tg = 5 ° C.,
Crystalline polypropylene resin film with mp = 139 ° C. and Xc = 50%. Tg (1-Xc) + mp · Xc = 72
° C. (Film thickness: 6 μm, X = 30%, Y = 200
g / mm ² ) Films were evaluated by bonding each film with a 150 mesh polyester gauze with a vinyl acetate adhesive (adhesive strength: 3
0g / 25mm width). Table 1 shows the evaluation results of the base paper.
All the examples were excellent in perforation sensitivity (in the case of two flash valves) and stability over time. In Comparative Example 1, since a crystalline polyester resin film having a crystallinity of 40% was used, the perforation sensitivity was insufficient and the printed matter was unclear.
Further, in Comparative Example 2, the perforation sensitivity is high, but the Tg is low, the print image quality is thick and the characters are slightly unclear, and the stability over time is poor.
Here, among the examples, Tg (1-Xc) + mp · Xc
When the temperature is 100 ° C. or lower, the perforation sensitivity is particularly excellent, and even one flash valve can perforate sufficiently. However, in Example 1, when the plate was made under the condition 1, since the plate making energy was larger than 2.0 J / cm ² , the characters tended to be slightly thicker and tended to be fused with the printed original. .

Therefore, it is considered that the heat-sensitive stencil printing base paper of the present invention is preferably plate-prepared at a plate-making energy of 2.0 J / cm ² or less in terms of the sharpness of the obtained printed matter.

[0027]

[Examples 5 and 6 and Comparative Examples 3 and 4] Polyester cloth having a mesh number shown in Table 1 was attached to the above film 1 with a vinyl acetate adhesive. All of the examples were excellent in both perforation sensitivity and stability over time, but in Comparative Example 3, the mesh was too fine and the printed matter was unclear. Further, in Comparative Example 4, since the mesh was coarse, the characters on the printed matter tended to be thick, and the stability over time also tended to be poor. Also, the adhesive strength is 2g / 25
When the width was set to mm, the film was peeled from the gauze when the master was to be peeled off from the printed original after flash plate making, and printing could not be performed. Also, the adhesive strength is 500g / 25mm
When the width was set, the gauze was clogged with the adhesive, and the ink did not come out even after printing, and only an unclear printed matter was obtained.

When Japanese paper was used instead of the polyester gauze, the perforation sensitivity was sufficient, but the fibers of the Japanese paper were conspicuous in the printed matter, and the printed matter was less clear than in Examples 3 and 4.

[0029]

Example 7 A film having a thickness of 0.5, 2, 15, 20 μm was produced using the thermoplastic polyester used in the film 1. The crystallinity, the heat shrinkage ratio, and the heat shrinkage stress were almost the same as those of the film 1. The film was bonded to a 150 mesh polyester gauze with a vinyl acetate-based adhesive to form a base paper, and the perforation sensitivity was measured. As a result, films with film thicknesses of 2 and 15 μm were “A”, but 0 Those using a thin film of 0.5 μm could not be peeled off from the printing original and could not be used for printing. Further, the result of using a thick film having a thickness of 20 μm was “Δ”.

[0030]

[Table 1]

[0031]

Industrial Applicability According to the present invention, a heat-sensitive stencil printing base paper suitable for plate making by flash light such as a xenon lamp or a flash bulb and having a good printing image quality and having no physical property change over time like a conventional base paper is obtained. Further, by using a plate making method capable of fully utilizing the heat-sensitive stencil printing performance of the above-mentioned base paper, a markedly beautiful printed matter can be obtained as compared with the conventional printed matter by the flash light plate making.

Claims (2)

[Claims] 1. A thermoplastic resin having a thickness of 1 to 15 μm.
In the stretched film satisfying the following formula (1), 50 to 30
0 mesh synthetic fiber gauze has an adhesive strength of 5 to 200 g /
Thermal stencil printing base paper laminated to a width of 25 mm. 50 ≦ Tg (1−Xc) + mp · Xc ≦ 140 (1) (where Tg (° C.) is the glass transition point, Xc is the crystallinity (0 ≦ Xc ≦ 1), and mp (° C.) is the melting point). is there.) 2. A method for making a heat-sensitive stencil printing base paper in which the base paper is perforated with flash light having an energy of 2.0 J / cm ² or less.