JP2001096940A - Heat-sensitive stencil printing film and heat-sensitive stencil printing master - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high quality heat-sensitive stencil printing film of low energy perforation properties and curling properties and generating the little lowering of the film quality with the change of time and also provide a heat- sensitive stencil printing master using the film. SOLUTION: A heat-sensitive stencil printing film is composed of a polymer composed of polylactic acid as a main body and a polyetheramide, and the heat shrinkage factor in the film longitudinal direction (vertical direction) at 65 deg.C for 60 minutes is 5% or less, and heat shrinkage factor at 100 deg.C for 10 minutes is 10% or more, and the film crystal melting energy is 5-65 J/g. The heat-sensitive stencil printing film is bonded with a porous substrate to manufacture a heat-sensitive stencil printing master.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermal head,
Alternatively, regarding a heat-sensitive stencil film and a heat-sensitive stencil master, which are perforated by a halogen lamp, a xenon lamp, a flash lamp, a laser beam, or the like,
More specifically, the present invention provides a high-quality heat-sensitive material having excellent perforation sensitivity, particularly excellent perforation at a low energy by a thermal head, and suppressing deterioration of perforation characteristics and curl properties of a heat-sensitive stencil master with aging. The present invention relates to a stencil printing film and a heat-sensitive stencil printing master.

[0002]

2. Description of the Related Art Conventionally, as a heat-sensitive stencil master, a vinylidene chloride film, a polyester film,
For thermoplastic resin films such as polypropylene film,
There is known a structure in which a porous support made of natural fiber, chemical fiber or synthetic fiber or a thin paper, nonwoven fabric, gauze or the like obtained by mixing them is bonded with an adhesive (for example, see Japanese Patent Application Laid-Open No. SHO 51-51). No. 2513, JP-A-57
182495).

[0003] However, recently, high resolution is required for printed matter. For example, in the case of perforation by a thermal head, in order to obtain high resolution, individual heads are made smaller and the head heating cycle is shortened, so that per unit area is reduced. Attempts have been made to increase the number of perforations. In such a case, in order to obtain the appropriate size of perforation in a short time,
In addition, in order to reduce the load on the thermal head and extend the service life, it is necessary to reduce the energy supplied to each head.
That is, higher sensitivity of the film is desired.

[0004] In addition, the poor curl property causes conveyance in a printing machine,
It is a major cause of troubles such as a printing error and master clogging at the time of plate discharge, and a film having good curl properties and having few troubles at the time of transport and plate discharge is required.

Conventionally, a film having improved printing characteristics by specifying the thermal characteristics of the film (Japanese Patent Laid-Open No. Sho 62-28)
2984, JP-A-3-39294, JP-A-4-224925, etc.)
Films in which the composition of the polymer is specified for the purpose of increasing the sensitivity of the film (JP-A-2-158391, JP-A-10-158
Japanese Patent Application Laid-Open No. 119453/1992) has been proposed, but is still insufficient in terms of perforation sensitivity and curling property, especially in a high-resolution printing machine requiring a large number of perforations per unit area, and these are satisfied simultaneously. What was needed was to be done. In addition, deterioration in film quality due to aging is also a problem, and a high-quality film with little aging has been demanded.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a high-quality heat-sensitive stencil printing film which cannot be realized by the prior art and has a low energy perforation property, curl property, and little deterioration in film quality due to aging. And a heat-sensitive stencil master using the heat-sensitive stencil film.

[0007]

Means for Solving the Problems The inventors of the present invention focused on the functions of the heat-sensitive stencil printing film and the heat-sensitive stencil printing master, and the mechanism of perforation stencil making and printing, and as a result, as a result, a polymer mainly composed of polylactic acid and a polylactic acid were obtained. It has been found that a film made of ether imide has high perforation, curl and long-term storage stability, and has completed the present invention.

That is, the present invention has the following constitution. [1] A heat-sensitive stencil film comprising polylactic acid and polyetherimide. [2] 100 ° C., 30 ° in the longitudinal direction (longitudinal direction) of the film
The heat-sensitive stencil film according to the above [1], wherein the heat shrinkage rate per minute is 10% or more. [3] The heat-sensitive stencil according to any of [1] or [2] above, wherein the film has a heat shrinkage in a longitudinal direction (longitudinal direction) of 60 ° C. for 10 minutes of 5% or less. Printing film. [4] The heat-sensitive stencil printing film according to any one of [1] to [3], wherein the polyetherimide is contained in an amount of 1 to 50% by weight. [5] The crystal melting energy of the film is 5 to 65 J / g.
The film for thermosensitive stencil printing according to any one of the above [1] to [4], wherein [6] The film for heat-sensitive stencil printing as described in any one of [1] to [4] above, wherein the thickness of the film is 0.2 μm or more and 8 μm or less. [7] A thermosensitive stencil master comprising the film according to any one of [1] to [6] and a porous support. [8] The heat-sensitive stencil master according to the above [7], wherein the film and the porous support are joined substantially without an adhesive. It is.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The heat-sensitive stencil film of the present invention must be a film composed of a polymer mainly composed of polylactic acid and polyetherimide. By using a raw material consisting of a polymer mainly composed of polylactic acid and polyetherimide, the film has good thermal properties, especially thermal shrinkage properties, excellent curl properties, and is sensitive to the heat given by the thermal head. It is possible to obtain a high-sensitivity film excellent in perforation at low energy. In addition, the long-term storage stability of the film near room temperature is improved, and a high-quality film with little change over time near room temperature can be obtained.

The polymer mainly composed of polylactic acid in the heat-sensitive stencil film of the present invention includes a lactic acid homopolymer, a copolymer of lactic acid and another hydroxycarboxylic acid, etc.
And mixtures thereof. As the lactic acid component constituting the polymer, L-lactic acid, D-lactic acid, or a mixture thereof can be used. Hydroxycarboxylic acids that can be used in combination with the lactic acid component include glycolic acid,
Examples thereof include 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, and 6-hydroxycaproic acid. Further, dicarboxylic acids and glycols can also be used as long as the effects of the invention are not impaired. The mixture of the lactic acid component and other components has a lactic acid component content of 50 m in the polymer.
It is preferable to use them in various combinations so as to be at least ol%.

The polyetherimide used in the heat-sensitive stencil printing film of the present invention is a polymer containing an aliphatic, alicyclic or aromatic ether unit and a cyclic imide group as repeating units. The polymer is not particularly limited as long as the polymer has For example, U.S. Pat. Nos. 4,141,927, 2,622,678, 2,606,912, 2,606,914, 2,596,565, 2,596,566, and 2,598,478, polyetherimides and 2,598,536. Japanese Patent No. 2599171, Japanese Patent Application Laid-Open No. 9-48852, Japanese Patent No. 256556, Japanese Patent No. 25664636, Japanese Patent No. 25664637, Japanese Patent No. 25656348, Japanese Patent No. 25653547, Japanese Patent No. 2558341, Japanese Patent No. 2558339. , Patent No. 2
No. 834580. As long as the effects of the present invention are not impaired, the main chain of the polyetherimide contains a cyclic imide, a structural unit other than an ether unit, for example, an aromatic, aliphatic, alicyclic ester unit, or an oxycarbonyl unit. May be.

In the present invention, the weight fraction of the polyetherimide is not particularly limited, but it is preferable that the polyetherimide is contained in an amount of 1 to 50% by weight. More preferably, it is 2 to 40% by weight, and still more preferably 3 to 30% by weight. If the content of polyetherimide is less than 1% by weight, it is necessary to pay attention because a change with time is large, a curl property is poor, and a film having poor transportability and plate discharging property may be obtained. On the other hand, if the polyetherimide content exceeds 50% by weight, the extensibility is reduced, and the extruded polymer is likely to contain unmelted materials. Care must be taken because it may be difficult to obtain the film of the invention.

The content of polyetherimide in the film can be determined by a known measurement. Next, L-lactic acid and Genera as polyetherimide
An example in which the content of polyetherimide in the film is determined by using Ultem 1010 manufactured by Electric Corporation will be described, but the present invention is not limited to this example.

The weighed film (Xg) is dissolved in a mixed solution of hexafluoroisopropanol and chloroform and then reprecipitated with acetone to obtain polyester and polyetherimide powder particles. The polyetherimide component was eluted into chloroform from the obtained powdery particles,
Filter out and weigh (Yg). From the formula (1), the content of the polyetherimide contained in the film is calculated. Polyetherimide content = Y / X × 100 [%] (Formula (1)) The heat shrinkage of the heat-sensitive stencil film of the present invention is determined by a required perforation method and is not particularly limited. But,
The longitudinal heat shrinkage of the film when treated at 65 ° C. for 60 minutes is preferably 5% or less. It is more preferably at most 3%, further preferably at most 1.5%.
When the heat shrinkage in the longitudinal direction of the film after treatment at 65 ° C. for 60 minutes is 5% or less, the curling property of the heat-sensitive stencil master made using this film becomes good,
It is preferable because the transportability and the plate discharging property in the printing machine are improved. Further, it is preferable because it hardly causes a change with time and the long-term storage property is enhanced.

The heat shrinkage of the heat-sensitive stencil film of the present invention is determined by the required perforation method, and is not particularly limited, but the heat shrinkage in the longitudinal direction of the film when treated at 100 ° C. for 10 minutes is 10%. It is preferable that it is above. More preferably 12% or more, further preferably 15% or more.
% Or more. When the heat shrinkage in the longitudinal direction of the film after treatment at 100 ° C. for 30 minutes is 8% or more, it is preferable because the pore diameter becomes large and uniform, and the perforation property is enhanced.

The crystal melting energy (ΔHu) of the heat-sensitive stencil film of the present invention is not particularly limited, but is preferably 5 to 65 J / g, more preferably 10 to 60 J / g.
g, particularly preferably 15 to 55 J / g. When ΔHu is 5 to 65 J / g, variation in perforation sensitivity of the film is small and image quality is high, so that it is preferable.

The thickness of the heat-sensitive stencil film of the present invention is not particularly limited, but is preferably from 0.2 to 8 μm, more preferably from 0.23 to 7 from the viewpoint of perforation and film-forming stability.
μm, more preferably 0.25 to 5 μm.

The heat-sensitive stencil film of the present invention is not particularly limited. However, from the viewpoint of improving perforation sensitivity and improving the image quality, the heat-sensitive stencil film is heated in the width direction and the longitudinal direction while the temperature is raised from room temperature to the melting point or the decomposition point. The peak value of the heat shrinkage stress when measuring the shrinkage stress is preferably 100 g / mm2 or more. More preferably 130 g / mm2
That is all.

The melting temperature of the heat-sensitive stencil film of the present invention is not particularly limited.
30-320 degreeC is preferable. More preferably, 140
To 310 ° C, more preferably 150 to 300 ° C.

In the heat-sensitive stencil master of the present invention, the ratio of the average perforated area before and after the treatment at 60 ° C. for 50 hours (the average perforated area after the treatment / the average perforated area before the treatment) is 0.85 or more. preferable. It is more preferably 0.9 or more, and still more preferably 0.93 or more. If the ratio of the average perforated area is smaller than 0.85, attention must be paid to the fact that the image quality of the master is remarkably deteriorated and printing defects such as missing prints may occur.

In the heat-sensitive stencil film of the present invention,
In order to improve workability during film winding process, coating at the time of master making, laminating process and printing, or to prevent fusion of the thermal head and film at the time of thermal perforation, the surface is roughened and moderate to film It is preferable to impart a smooth sliding property, inorganic particles and organic particles as long as the effect of the present invention is not impaired, various other additives, such as a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, An antistatic agent, a whitening agent, a coloring agent, a conductive agent, and the like may be added.

Specific examples of the inorganic particles include silicon oxide,
Oxides such as aluminum oxide, magnesium oxide, and titanium oxide; complex oxides such as kaolin, talc, and montmorillonite; carbonates such as calcium carbonate and barium carbonate; sulfates such as calcium sulfate and barium sulfate; barium titanate; Titanate such as potassium, phosphate such as tertiary calcium phosphate, dibasic calcium phosphate, and monocalcium phosphate can be used, but not limited thereto. These may be used in combination of two or more depending on the purpose.

Specific examples of the organic particles include polystyrene or crosslinked polystyrene particles, vinyl particles such as styrene / acrylic / acrylic crosslinked particles, styrene / methacrylic / methacrylic crosslinked particles, benzoguanamine / formaldehyde, silicone, and polytetrafluoroethylene. Although particles such as fluoroethylene can be used, the particles are not limited thereto, and any particles may be used as long as at least a part of the particles constituting the particles is organic polymer fine particles insoluble in polyester. The organic particles preferably have a spherical particle shape and a uniform particle size distribution from the viewpoint of smoothness and uniformity of formation of projections on the film surface.

The particle size, blending amount, shape and the like of these particles can be selected according to the application and purpose.
The average particle size is preferably in the range of 0.01 μm to 3 μm, and the blending amount is preferably in the range of 0.01 to 6% by weight.

The heat-sensitive stencil film of the present invention may be an unstretched or unoriented film, but may be formed into a uniaxially or biaxially stretched and heat-fixed oriented film by a known method to obtain strength, film forming stability and the like. The effect is more remarkably exhibited. In particular, a film formed by a stenter sequential biaxial stretching method is preferable in terms of thickness uniformity.

The heat-sensitive stencil master of the present invention comprises a film and a porous support bonded to each other. The porous support is a porous material made of natural fibers, synthetic fibers, and the like, which can transmit the printing ink and does not substantially undergo thermal deformation under heating conditions under which the film is perforated. Non-woven fabric, woven fabric, gauze or other porous material.

The basis weight of the porous support bonded to the film of the present invention is preferably from 1 to 20 g / m ² from the viewpoint of printability. More preferably, it is ^{2 to} 16 g / m ² , still more preferably ² to 14 g / m ² . When the basis weight is 20 g / m ² or less, the ink permeability becomes good, and the printed image does not fade even when the printing speed is increased. Also,
When the basis weight is 1 g / m ² or more, it is possible to obtain an excellent master having good ink holding properties and capable of obtaining a clear image.

The average diameter of the fibers constituting the porous support is preferably 0.5 to 20 μm, more preferably 1 to 15 μm, further preferably 1 to 10 μm, and particularly preferably 1 to 5 μm. When the average diameter is 20 μm or less, a master having uniform ink permeability can be obtained. When the average diameter is 0.5 μm or more, sufficient strength as a support can be obtained, so that the transportability becomes good.

Further, all the fibers constituting the porous support may have the same diameter, or fibers having different fiber diameters may be mixed.

The porous support bonded to the heat-sensitive stencil film of the present invention is preferably a porous support made of a stretched thermoplastic fiber from the viewpoint of mechanical strength and heat resistance.

The crystal melting energy of the porous support (ΔH
u) is preferably from 20 to 65 J / g, more preferably from 30 to 65 J / g, from the viewpoint of plate discharging property and durability after plate making. In addition, the crystallinity of the porous support is preferably 20% or more, more preferably 30% or more, from the viewpoint of plate discharging property after plate making in perforation.

The porous support may have the same fiber diameter or a mixture of fibers having different fiber diameters. Further, the porous support is not limited to a single-layer structure, and may have a multilayer structure in which materials having different average fiber diameters are laminated stepwise.

The method for producing the heat-sensitive stencil film of the present invention will be described below, but the present invention is not limited thereto.

In the present invention, the heat-sensitive stencil film can be manufactured by the following method. In the present invention, the heat-sensitive stencil printing film is, for example, after sufficiently drying the polymer mainly composed of polylactic acid and polyetherimide, and then feeding the extruder to melt in a 150-350 ° C. extruder to form a T-die. An unstretched film is obtained by extruding on a cast drum by an extrusion method. The drying condition of the resin at this time is preferably performed for 3 hours or more by reducing the pressure to 10 Torr or less at a drying temperature of Tg-30 ° C. or more and the melting point or less for the purpose of removing moisture and low molecular weight substances in the resin, and 5 Torr or less. More preferably for 5 hours or more. As for the extrusion conditions, it is preferable to extrude at a lower temperature and a shorter residence time within a range that does not affect the formation of the unstretched film, in order to suppress the thermal decomposition of the resin.

In order to improve the adhesion between the molten film and the cooling roll, the electrostatic application adhesion method or the liquid surface application adhesion method is preferably employed. At this time, the unstretched film can have a desired thickness by adjusting the slit width of the die, the discharge amount of the polymer, and the rotation speed of the cast drum. The unstretched film can be biaxially stretched by simultaneously or successively biaxially stretching it with a roll or a tenter in view of film forming stability and film thickness uniformity. In the case of sequential biaxial stretching, the stretching order may be the longitudinal direction of the film, the width direction, or vice versa. Further, in the sequential biaxial stretching, stretching in the longitudinal direction and the width direction can be performed in two or more steps, respectively. The stretching conditions of the film can be appropriately adjusted according to the desired heat shrinkage characteristics, orientation degree, strength and elastic modulus of the film, and can be performed by any method. The stretching temperature of the film is determined by the glass transition temperature (T
g) It is preferable to carry out at a lower temperature in the temperature range of -30 ° C or higher and the crystallization temperature of the resin + 30 ° C or lower. The stretching ratio in the longitudinal direction and the width direction of the film can be set to any value from 1.2 to 10 times that allows setting the stretching temperature lower, and is preferably 1.5 times or more. Either of the stretching ratio in the longitudinal direction and the stretching ratio in the width direction may be increased, and may be the same. In addition, the unstretched film has an area magnification of 5
It is also possible to perform biaxial stretching at the same time so that the magnification becomes up to 50 times.

The film thus obtained can be heat-treated by any method for the purpose of improving the strength, stability over time, and shrinkage characteristics. The heat treatment temperature is preferably lower than 30 ° C. or higher but lower than the melting point, more preferably 13 ° C.
The temperature is 0 ° C. or lower, more preferably 100 ° C. or lower. The heat treatment time can be arbitrarily set, but is about 1 second to 5 minutes. Preferably, it is performed in the range of 1 to 60 seconds. The heat treatment may be performed while the film is relaxed in the longitudinal direction and / or the width direction, and may be cooled stepwise. The film of the present invention may be subjected to various surface treatments such as corona discharge treatment, chemical treatment, flame treatment, ultraviolet treatment, and plasma treatment in order to improve the adhesion to the porous support.

Further, a coating treatment can be performed as required. By providing a release layer on the film, stick preventing properties and adhesion preventing properties with the document may be imparted, or adhesive properties with the porous support and antistatic properties may be imparted.

In the heat-sensitive stencil master of the present invention,
Adhesion between the thermoplastic film and the porous support made of thermoplastic fibers may be via an adhesive such as a vinyl acetate resin, an acrylic resin, a urethane resin, or a polyester resin. It may be adhered without. The method for bonding without the use of an adhesive is not particularly limited, but a method of laminating a thermoplastic film and a porous support made of thermoplastic fibers and performing thermocompression bonding is preferred.

The porous support used in the present invention is preferably a biaxially stretched unstretched nonwoven fabric made of thermoplastic fibers. The method of biaxial stretching may be any of a sequential biaxial stretching method and a simultaneous biaxial stretching method as in the case of the above-mentioned film. In the case of the sequential biaxial stretching method, the unstretched nonwoven fabric is generally stretched in the longitudinal direction and the transverse direction in general, but may be stretched in the opposite direction. The stretching ratio is not particularly limited and is appropriately determined depending on the type of the polymer to be used, but is preferably 2 to 8 times, and more preferably 3 to 8 times, each in the vertical and horizontal directions. After that, the porous support after the biaxial stretching may be heat-treated. Heat treatment temperature is 50
To 150 ° C., and the heat treatment time is 0.5 seconds to 10 seconds.
Minutes are preferred. Next, a thermosensitive stencil master can be produced by bonding a porous support composed of a thermoplastic film and a thermoplastic fiber with an adhesive.

The method of thermocompression bonding of the porous support comprising a thermoplastic film and thermoplastic fibers in the present invention is not particularly limited.
It is particularly preferable in view of the easiness of the process. In the present invention, the thermocompression bonding is preferably performed after the thermoplastic film is cast and before the stretching step. Thermocompression bonding temperature is 50 ° C to glass transition temperature (Tg) of thermoplastic fiber + 2
Preferably between 0 ° C.

Next, co-stretching of a thermocompressed thermoplastic film and an unstretched non-woven fabric made of thermoplastic fibers can also be preferably used. By co-stretching in the state of thermocompression bonding, the film and the porous support can be stretched integrally. In addition, by co-stretching both, the porous support made of thermoplastic fiber serves as a reinforcing member, and the thermoplastic film can be formed extremely stably without being broken.

Further, the film, once cooled to 30 ° C. or less after the heat treatment, is heated under tension or no tension at 40 to 100 ° C.
The film is subjected to an aging treatment at a temperature of about 10 seconds to about one week to adjust the thermal characteristics of the film. This aging treatment may be incorporated into the film forming step as in the case of the heat treatment, but it is more preferable to perform such treatment on a roll-shaped film obtained by winding once after the heat treatment.

In the present invention, the above-mentioned "co-stretching" means that the unstretched nonwoven fabric is laminated with a film and then both stretched.

In the method of co-stretching in the present invention, biaxial stretching is preferred from the viewpoint of improving the perforation sensitivity of the film and the uniform dispersibility of the fibers forming the porous support made of thermoplastic fibers. The biaxial stretching may be either a sequential biaxial stretching method or a simultaneous biaxial stretching method. In the case of the sequential biaxial stretching method, stretching is generally performed in the order of the longitudinal direction and the transverse direction, but may be performed in the opposite direction. The stretching temperature is preferably between the glass transition temperature (Tg) of the polyester fiber used for stretching and the elevated crystallization temperature (Tcc). The stretching ratio is not particularly limited, and is appropriately determined depending on the type of the polymer for the thermoplastic film to be used, the perforation sensitivity required for the thermosensitive stencil master, and the like.
About 5 times is appropriate. After biaxial stretching, the film may be stretched longitudinally, horizontally, or vertically and horizontally again. Further, it is also preferable to subject the heat-sensitive stencil master of the present invention to heat treatment after biaxial stretching. Further, after the heat-sensitive stencil master obtained by the treatment is once cooled to about room temperature,
Aging can be performed at a relatively low temperature of 0 to 90 ° C. for about 5 minutes to 1 week. When such aging is employed, curling and wrinkling are less likely to occur during storage of the heat-sensitive stencil master or in a printing machine, which is particularly preferable.

The heat-sensitive stencil printing master of the present invention comprises a silicone oil, a silicone-based resin,
It is preferable to provide a thin layer comprising a fluororesin, a surfactant, an antistatic agent, a heat-resistant agent, an antioxidant, organic particles, inorganic particles, a pigment, a dispersing agent, a preservative, an antifoaming agent, and the like. The thickness of the thin layer for preventing fusion is preferably 0.005 to 0.4.
μm, and more preferably 0.01 to 0.4 μm.

In the heat-sensitive stencil master of the present invention,
When a thin layer for preventing fusion is provided, it is preferable to apply the coating solution in the form of a coating solution dissolved, emulsified or suspended in water, and then remove the water by drying or the like. The coating may be performed before or after stretching the film. In order to make the effect of the present invention more remarkable, when performing sequential biaxial stretching such as transverse stretching after longitudinal stretching,
It is particularly preferable to apply before stretching in the case where transverse stretching is performed or when simultaneous biaxial stretching is performed. The application method is not particularly limited, but application is preferably performed using a roll coater, a gravure coater, a reverse coater, a bar coater, or the like. Before providing the thin layer for preventing fusion, an activation treatment such as a corona discharge treatment may be applied to the coated surface in air or other various atmospheres as necessary.

[Measurement Method of Properties] (1) Heat Shrinkage (%) The heat shrinkage in the longitudinal direction and width direction of the film was measured according to the method specified in JIS C-2318. The sampling method was the same as for the sample of the elastic modulus. A sample having a sample width of 10 mm and a sample length of 200 mm was heat-treated in a gear oven at 65 ° C. for 60 minutes, at 100 ° C. for 10 minutes, and the heat shrinkage was calculated from the change in sample length by the following equation.

Heat shrinkage (%) = [(length before heat treatment−length after heat treatment) / length before heat treatment] × 100 (2) Melting temperature, crystallization temperature, melting energy (ΔH
u), glass transition temperature (Tg) As a differential scanning calorimeter (DSC), a robot DSC “RDSC220” manufactured by Seiko Denshi Kogyo Co., Ltd. was used.
SC / 5200 "on an aluminum pan
g of composition or film sample. The temperature of this sample was raised from room temperature at a rate of 20 ° C./min.
An SC curve was obtained. Melting temperature, elevated temperature crystallization temperature, JIS
It was determined according to K-7121. First, the area of the crystal melting endothermic peak was determined, and the same DSC
Under the measurement conditions, the area was determined based on the area of the melting endothermic peak of indium. Subsequently, the sample that has once been melted is rapidly cooled, and then heated from normal temperature at a rate of 20 ° C./min.
A C curve was obtained. The glass transition temperature is determined according to JIS K-712.
I asked according to 1.

(3) Maximum heat shrinkage stress of the film A film sample having a width of 4 mm and a measurement length of 20 mm was used as a thermal analyzer EXSTA manufactured by Seiko Instruments Inc.
R6100, 25 ° C to 10 ° C under constant measurement length conditions
/ Min was measured at a heating rate. The maximum heat-collection stress was determined from the obtained curve.

(4) Film Thickness Ten film samples were arbitrarily selected, cut out in the cross-sectional direction, photographed with an electron microscope at a magnification of 2000 times, and the film thickness was measured. This was performed for ten photographs and expressed as an average value.

(5) Average Fiber Diameter The average fiber diameter is determined by taking 10 photographs of an arbitrary 10 places of the porous support at a magnification of 2000 times using an electron microscope and arbitrarily selecting 15 photographs per photograph. The diameter of the fiber of the book was measured, and this was carried out for 10 photographs, and a total of 150
The fiber diameter of the book is measured, and the average value is shown.

(6) Weight per unit area The polyester film was carefully peeled off from the heat-sensitive stencil master, the porous support was cut into a size of 20 × 20 cm, and the weight was measured and converted to the weight per square meter.

(7) Perforation characteristics The prepared master was used as RISOGR manufactured by Riso Kagaku Corporation.
It was supplied to the APH "GR377", and a 5 mm square black solid plate was made into a grid by a thermal head plate making method (600 dpi). At this time, the energy applied to the thermal head was 17 μJ per dot. Perforation was performed in this state, and 100 perforated portions of the film were observed with a scanning microscope at a magnification of 200 times, and the area of the perforated portion of the film was measured. The average value and standard deviation of the perforated area per dot were obtained, and the perforation characteristics were evaluated by the following items. Both 感 度 and ○ are practically usable for both sensitivity and variation.

A. Perforation sensitivity ：: The average perforation area is 450 μm 2 or more.

：: Average perforated area is 300 μm 2 or more 4
Less than 50 μm 2.

Δ: Average perforated area is 150 μm 2 or more 3
Less than 00 μm 2.

×: Those having an average perforated area of less than 150 μm 2.

B. Perforation variation Variation degree = 10 × log (average perforated area / standard deviation of perforated area) 2 ◎: Variation degree of 15 or more ：: Variation degree of 10 or more and less than 15

Δ: The degree of variation is 5 or more and less than 10.

C: The degree of variation is less than 5.

(8) Evaluation of curl properties A thermosensitive stencil master was cut into 10 cm squares, allowed to stand at 50 ° C. for 30 minutes, and the curl state when the film layer was placed on a flat plate was observed. Was evaluated.

[0086] The one that maintains a flat surface without curling at all is indicated by “◎”. The one that has a slight lift at the end portion but has a lift height of 1 cm or less is indicated by “○”. Is greater than 1 cm and less than or equal to 3 cm, "△" is given when the lift at the end exceeds 3 cm is given as "x". ◎ and ○ are for practical use.

(9) Evaluation of long-term storage stability The heat-sensitive stencil master was treated at 60 ° C. for 50 hours, and the perforation characteristics and curl were evaluated based on the above (7) perforation characteristics and (8) curl evaluation.

[0065]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 To 100 parts by weight of an L-lactic acid polymer synthesized from 80 parts by weight of L-lactic acid and 20 parts by weight of hydroxycaproic acid, 0.5 part by weight of calcium carbonate particles having an average particle size of 1.5 μm was added. After mixing, 2
The mixture was supplied to a screw extruder and extruded at 200 ° C. to obtain polymer pellets mainly composed of polylactic acid. The obtained pellet was treated at 50 ° C. under reduced pressure for crystallization and drying.
The pellets and a polyetherimide (= General Elec) dried in a vacuum dryer at 140 ° C. for 3 hours or more.
tric Ultem 1010 (hereinafter Ultem, IV =
0.68)) were mixed in a ratio of 9: 1, and the pellets were fed to an extruder having a screw diameter of 45 mm, extruded at a T-die die temperature of 290 ° C., and extruded at a diameter of 300 m.
m and cast on a drum cooled to 25 ° C to a thickness of 13
A μm unstretched film was produced. Next, the unstretched film is stretched 2.5 times in the longitudinal direction between heating rolls at 70 ° C., fed into a tenter type stretching machine, stretched 2.5 times in the width direction at 75 ° C., and further stretched in a tenter by 80 times. 1 in ° C
Heat treatment was performed for 0 seconds to produce a biaxially stretched film having a thickness of 2.0 μm. Then, using a vinyl acetate adhesive on one side of the obtained film, a basis weight of 10 g containing Manila hemp as a main component
/ M ² of Japanese paper, and a silicone-based release agent is applied to the other side of the film using a bar coater.
A heat-sensitive stencil master was applied at a coating rate of 05 g / m ² .
Tables 1 and 2 show the evaluation results of the obtained film and the master.

Example 2 L-lactic acid synthesized using 100 parts by weight of L-lactic acid instead of L-lactic acid polymer synthesized from 80 parts by weight of L-lactic acid and 20 parts by weight of hydroxycaproic acid
-A film was formed in the same manner as in Example 1 except that a lactic acid polymer was used, and a heat-sensitive stencil master was prepared and printed. Tables 1 and 2 show the evaluation results of the film and the master.

(Example 3) In place of the polymer mainly composed of polylactic acid used in Example 1, L-lactic acid used in Example 1 was used.
Copolymer of 85 parts by weight of lactic acid, poly-3-hydroxybutyric acid and poly-3-hydroxyvaleric acid (copolymerization molar ratio 92/8) 1
To 5 parts by weight, 0.3 parts by weight of calcium carbonate particles having an average particle size of 1.0 μm were added, mixed and supplied to a twin-screw extruder.
A film was formed in the same manner as in Example 1 except that a polymer mainly composed of polylactic acid obtained by extrusion was used, and a heat-sensitive stencil master was prepared and printed. Tables 1 and 2 show the evaluation results of the film and the master.

Example 4 The polymer mainly composed of polylactic acid used in Example 1 and Ultem were mixed at a ratio of 8: 2, and the stretching temperature in the longitudinal direction and the stretching direction in the width direction were 75 ° C. and 8 ° C., respectively.
A film was formed in the same manner as in Example 1 except that the temperature was set at 0 ° C., and a heat-sensitive stencil master was prepared and printed. Tables 1 and 2 show the evaluation results of the film and the master.

(Example 5) A film was prepared in the same manner as in Example 1 except that an unstretched film having a thickness of 10 µm was formed, and a biaxially stretched film having a thickness of 1.5 µm was formed. Using the unstretched film, a heat-sensitive stencil master was prepared and printed in the same manner as in Example 1. Tables 1 and 2 show the evaluation results of the film and the master.

Example 6 A biaxially stretched film having a thickness of 3.0 μm was prepared in the same manner as in Example 1, except that an unstretched film having a thickness of 20 μm was prepared. Using the unstretched film, a heat-sensitive stencil master was prepared and printed in the same manner as in Example 1. Tables 1 and 2 show the evaluation results of the film and the master.

(Example 7) Hole diameter 0.35 mm, number of holes 10
Using 0 rectangular spinnerets, a copolymerized polyester of ethylene terephthalate and ethylene isophthalate (copolymer molar ratio of 80) at a die temperature of 290 ° C. and a discharge rate of 35 g / min.
/ 20) was spun out by a melt blow method, the fibers were collected on a conveyor, and calendered between metal rolls heated to 70 ° C. to produce an unstretched nonwoven fabric having a basis weight of 100 g / m ² .

Separately, the polymer mainly composed of polylactic acid used in Example 2 was dried at 120 ° C. under reduced pressure for 3 hours, and then the extruder having a screw diameter of 45 mm was used to obtain a T die die temperature of 29.
It was extruded at 5 ° C. and cast on a cooling drum having a diameter of 300 mm to produce an unstretched film.

The obtained unstretched film and the unstretched nonwoven fabric were overlaid, supplied to a heating roll, and thermocompression-bonded at a roll temperature of 105 ° C. The thus obtained laminate is stretched 2.5 times in the length direction between heating rolls at 85 ° C., and then fed into a tenter-type stretching machine and stretched 3.0 times in the width direction at 90 ° C. Heat treatment was performed at 90 ° C. in a tenter to prepare a heat-sensitive stencil master having a thickness of 70 μm, and printing was performed. On the film surface of the master, a wax-based release agent was applied using a gravure coater at a weight of 0.1 g / m ² after drying at the entrance of the tenter. The fiber weight of the obtained master was 12 g / m ² , and the average fiber diameter was 6 μm. Table 2 shows the evaluation results of the master.

Comparative Example 1 A film was formed in the same manner as in Example 1 except that no polyetherimide was used, and a heat-sensitive stencil master was prepared and printed. Tables 1 and 2 show the evaluation results of the film and the master.

Comparative Example 2 A film was formed in the same manner as in Example 1 except that the stretching temperature and the heat treatment temperature in the longitudinal direction and the width direction were changed to 65 ° C., 70 ° C., and 75 ° C., respectively, without using polyetherimide. Then, a heat-sensitive stencil master was prepared and printed. Tables 1 and 2 show the evaluation results of the film and the master.

Comparative Example 3 Example 2 was repeated except that the polyetherimide was not used and the heat treatment temperature was 125 ° C.
A heat-sensitive stencil master was prepared and printed in the same manner as described above. Tables 1 and 2 show the evaluation results of the film and the master.
Shown in

Comparative Example 4 A film was formed in the same manner as in Example 7 except that no polyetherimide was used, and a heat-sensitive stencil master was prepared and printed. Table 2 shows the evaluation results of the master.

(Comparative Example 5) Instead of using polylactic acid, polyethylene terephthalate was used, and the stretching temperature and the heat treatment temperature in the longitudinal and width directions were 90 ° C and 95 ° C, respectively.
Except that the temperature was set to 100 ° C. and 100 ° C.
A thermosensitive stencil master was prepared and printed. Tables 1 and 2 show the evaluation results of the film and the master.

From these results, it is clear that the heat-sensitive stencil master prepared by using the film of the present invention has excellent perforation characteristics and curling properties, and high-quality heat-sensitive stencil printing excellent in perforation characteristics and curling properties over time. You know you are a master.

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[Table 1]

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[Table 2]

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The heat-sensitive stencil film disclosed in the present invention, which comprises a polymer mainly composed of polylactic acid and polyetherimide, has excellent low-energy perforation properties, curl properties, and changes over time. A high-quality heat-sensitive stencil printing film with little accompanying deterioration in film quality and a heat-sensitive stencil master using the film are extremely high in industrial value.

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Claims (8)

[Claims] 1. A heat-sensitive stencil film comprising a polymer mainly composed of polylactic acid and polyetherimide. 2. 65 in the longitudinal direction (longitudinal direction) of the film.
The heat-sensitive stencil film according to claim 1, wherein the heat shrinkage at 60C for 60 minutes is 5% or less. 3. The film in the longitudinal direction (longitudinal direction) of 100
3. The heat-sensitive stencil film according to claim 1, wherein the heat shrinkage at 10 [deg.] C. for 10 minutes is 10% or more. 4. The heat-sensitive stencil film according to claim 1, wherein the content of the polyetherimide is 1 to 50% by weight. 5. The film has a crystal melting energy of 5-6.
The heat-sensitive stencil film according to any one of claims 1 to 4, wherein the film is 5 J / g. 6. A film having a thickness of not less than 0.2 μm and not more than 8 μm.
The heat-sensitive stencil film according to claim 1, wherein: 7. A heat-sensitive stencil master comprising the film according to claim 1 and a porous support. 8. The heat-sensitive stencil master according to claim 7, wherein the film and the porous support are joined substantially without an adhesive.