JP2001130161A - Heat-sensitive stencil printing film and heat-sensitive stencil printing master - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive stencil printing film and a heat-sensitive stencil printing master of superior perforation properties under the low energy, printability and carrying properties and of little change with time generated by the effect of temperature and humidity. SOLUTION: A heat-sensitive stencil printing film is constituted of a polymer layer composed mainly of a polylactic acid and another polymer layer containing the polylactic acid of less than 50 wt.% laminated together, and a heat-sensitive stencil printing master is formed of the above laminated film bonded with a porous substrate.

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 stencil film and a high-quality heat-sensitive stencil sheet which are excellent in low-energy piercing properties, image properties, and transportability, and in particular, suppress deterioration of piercing properties and curling properties with aging. It is about the master.

[0002]

2. Description of the Related Art Conventionally, as a heat-sensitive stencil master, a vinylidene chloride film, a polyester film,
Or thermosensitive stencil printing with a structure in which a porous support composed of natural fiber, chemical fiber or synthetic fiber or thin paper, nonwoven fabric, gauze, etc., made of a mixture thereof is bonded to a thermoplastic resin film such as a polypropylene film with an adhesive. Masters are known (for example, see JP-A-51-25).
No. 13 and 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 suppress the load on the thermal head and extend the service life, it is necessary to reduce the energy supplied to each head, and it is desired that the film is perforated with low energy, that is, a higher sensitivity of the film is desired. I have.

Further, in order to stably obtain a high-resolution printed image, it is desired that the inside of a printing machine such as a thermal head or a transport roll or a printing paper is not stained or damaged.

[0005] In addition, there is a demand for good transportability in a printing press, and there is a need for a film which is free from troubles such as a printing error and a master clogging during transport caused by poor curl properties.

Furthermore, in order to maintain stable quality such as sensitivity and transportability, there is a demand for a film which does not cause deterioration in quality such as dimensional change of the film or master due to the influence of temperature and humidity, sensitivity and curl.

Hitherto, there have been proposed films having improved printing characteristics by defining the thermal characteristics of the films (Japanese Patent Application Laid-Open Nos. 62-282988 and 3-392).
94, JP-A-4-224925),
A film or the like in which the composition of the polymer is specified for the purpose of increasing the sensitivity of the film has been proposed (JP-A-2-15839).
No. 1, JP-A-10-119453), particularly in a high-resolution printing machine which requires a large number of perforations per unit area, the perforation sensitivity, printability, and transportability are still insufficient. That satisfy at the same time. In addition, a high-quality material with little change over time due to the influence of temperature and humidity has been demanded.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent low-energy piercing property, printability, and transportability, which have not been realized by the prior art, and have a small change with time due to the influence of temperature and humidity. Another object of the present invention is to provide a heat-sensitive stencil printing film and a heat-sensitive stencil printing master using the heat-sensitive stencil printing film.

[0009]

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, the polymer layer mainly composed of polylactic acid was formed. By forming a laminated film with a polymer layer containing less than 50% by weight of a polylactic acid component, a high-quality heat-sensitive stencil having high sensitivity, excellent printability, excellent transportability, and little change over time due to the influence of temperature and humidity. The inventors have found that a printing film can be obtained, and have completed the present invention.

That is, the present invention has the following constitution. [1] A heat-sensitive stencil film comprising a laminated film of a polymer layer mainly composed of polylactic acid and a polymer layer containing less than 50% by weight of a polylactic acid component. [2] The heat-sensitive stencil film according to [1], wherein a dimensional change when treated in an environment of a temperature of 50 ° C. and a humidity of 50% for 50 hours is less than 3%. [3] The film for heat-sensitive stencil printing as described in any of [1] or [2] above, wherein the lactide content of the laminated film is 0.5% by weight or less. [4] The film for heat-sensitive stencil printing according to any one of [1] to [3], wherein the thickness of the laminated film is 0.2 to 8 μm. [5] The heat-sensitive stencil printing according to any one of the above [1] to [4], wherein the polymer layer in which the polylactic acid component is less than 50% by weight is made of polyester or polyester and polylactic acid. the film. [6] A heat-sensitive stencil master comprising the laminated film according to any one of [1] to [5] and a porous support. [7] The heat-sensitive stencil master according to the above [6], wherein the laminated film and the porous support are joined substantially without an adhesive.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with preferred embodiments.

The heat-sensitive stencil printing film of the present invention needs to be composed of a laminated film of a polymer layer mainly composed of polylactic acid and a polymer layer containing less than 50% by weight of a polylactic acid component.

By forming a laminated film of a polymer layer mainly composed of polylactic acid and a polymer layer containing less than 50% by weight of a polylactic acid component, the film is excellent in printability and transportability and is sensitive to heat from a thermal head. A highly sensitive heat-sensitive stencil film having excellent low-energy perforation properties can be obtained. In addition, a high-quality heat-sensitive stencil film with little change over time due to the influence of temperature and humidity can be obtained.

The heat-sensitive stencil film of the present invention has a polylactic acid-based polymer layer and a polylactic acid component at the same time.
It is necessary to have a polymer layer that is less than 0% by weight. If it is a single layer consisting mainly of a polylactic acid-based polymer layer, it is easily affected by temperature and humidity, causing aging such as deterioration of perforation and curling, and stable quality such as perforation and transportability. I can't get anything. In addition, the polylactic acid component is 50
If it is a single layer containing only the polymer layer of less than% by weight, sufficient sensitivity may not be obtained, and in particular, low-energy perforation in a high-resolution machine having a large number of perforations per unit area may be poor.

The polymer mainly composed of polylactic acid in the heat-sensitive stencil printing film of the present invention includes a lactic acid homopolymer, a copolymer of lactic acid and another hydroxycarboxylic acid, etc.
And a mixture thereof, wherein the amount of the polylactic acid component is 50% by weight or more. As the lactic acid component constituting the polymer, L-lactic acid, D-lactic acid, or a mixture thereof can be used. Examples of the hydroxycarboxylic acids that can be used in combination with the lactic acid component include glycolic acid, 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 polymer layer mainly composed of polylactic acid in the heat-sensitive stencil printing film of the present invention may have a polylactic acid component content of 60% by weight or more in the polymer constituting the layer from the viewpoint of the perforation property of the film. From the viewpoint of moldability, the amount of the L-lactic acid component in the total lactic acid component is more preferably at least 75 mol%, further preferably at least 85 mol%, particularly preferably at least 90 mol%. preferable.

The polymer layer containing less than 50% by weight of the polylactic acid component in the heat-sensitive stencil printing film of the present invention is determined by the required perforation sensitivity and the temperature and humidity environment to be used. It is more preferably at most 15% by weight, more preferably at most 15% by weight.

The polymer layer containing less than 50% by weight of a polylactic acid component in the heat-sensitive stencil printing film of the present invention is preferably made of a biaxially stretchable thermoplastic resin, and comprises a dicarboxylic acid component and a glycol component. Polyester and polylactic acid, other polyolefin resins, polyvinyl chloride resins, etc., which are determined by the required perforation sensitivity, the temperature and humidity environment used, and the film has good moldability and curl properties. From the viewpoint, it is more preferable that the polyester resin is made of polyester or polyester and polylactic acid.

The lamination structure of the heat-sensitive stencil film of the present invention is not particularly limited, but the polymer layer mainly composed of polylactic acid is A, the polymer layer containing less than 50% by weight of the polylactic acid component is B, and the other layers are B. If C, A / B, A
/ B / A, B / A / B, A / B / C, B / C / A / C /
B and the like. At this time, the polymer layer containing less than 50% by weight of the polylactic acid component is provided on the side of the contact surface with the thermal head at the time of perforation and plate making, so that the surface of the lactic acid oligomer which may stain the thermal head or the printing machine is removed. It is preferable because the amount of precipitation can be suppressed, and the outermost layer is more preferable.

The polymer layer mainly composed of polylactic acid is preferably at least 50%, more preferably at least 70%, more preferably at least 70% with respect to the total thickness of the laminated film from the viewpoint of improving the perforation property. % Is more preferable.

The thickness of the heat-sensitive stencil film of the present invention is determined by the sensitivity required for the base paper, the perforation method used, the handleability of the film, etc., but is preferably 0.2 to 8 μm. More preferably 0.3 to 7μ
m, more preferably 0.5 to 5 μm.

The heat-sensitive stencil film of the present invention is preferably stretched in at least one direction. In an unstretched film, the heat shrinkage is small and the film is melted at the time of perforation, but the hole is difficult to expand, resulting in poor perforation sensitivity, and the film strength is low, so that the film may be broken at the time of printing a large number of copies. It is more preferable that the film is biaxially stretched from the viewpoint that the holes are easily uniformly expanded at the time of drilling, and the drilling sensitivity particularly at low energy is improved.

The heat-sensitive stencil printing film of the present invention has a dimension when treated for 50 hours in an environment of a temperature of 50 ° C. and a humidity of 50% from the viewpoint that the aging stability of the quality such as perforation sensitivity and curling property is good. The rate of change is preferably less than 3%, more preferably less than 2%, and even more preferably less than 1%.

The film for heat-sensitive stencil printing of the present invention has a lactide content of 0. 0 from the viewpoint that lactic acid oligomers and the like in the film do not stain the thermal head and the perforation sensitivity, printability and transportability are good. It is preferably at most 5% by weight. More preferably, the amount of lactide is 0.3% by weight or less, further preferably 0.2% by weight or less.

The lactide in the heat-sensitive stencil printing film of the present invention is LL-lactide, DD-lactide, DL (meso)-which is a cyclic dimer of a lactic acid component constituting the above-mentioned polymer mainly composed of polylactic acid. Lactide.

The heat shrinkage of the heat-sensitive stencil film of the present invention is determined by the required sensitivity and the method of perforation to be used, and the heat shrinkage in at least one direction after treatment at 100 ° C. for 10 minutes is determined. It is preferably from 10 to 90%, more preferably from 30 to 75%. More preferably, each of the ranges is in the above-described range in both the longitudinal direction and the width direction of the film.

The heat-sensitive stencil printing film of the present invention is preferable because the effects of the present invention are more remarkably exhibited when the surface characteristics of the film, that is, the center line average roughness and the maximum roughness are in the ranges described below. .

That is, the central average roughness [Ra] of the heat-sensitive stencil film of the present invention is 0.01 to 0.5 μm.
The range is preferably 0.05 to 0.4 μm from the viewpoints of stable productivity and perforation properties from the film formation to the master preparation step, and the printability.
Is more preferred.

The maximum roughness [Rt] of the film for heat-sensitive stencil printing of the present invention is preferably in the range of 0.3 to 5 μm, and 0.5 to 0.5 μm in view of the film handling, productivity, and variation in perforation sensitivity. 4 μm is more preferred.

The crystal melting energy [ΔHu] of the heat-sensitive stencil printing film of the present invention is 20 to 60 J / J from the viewpoint that a dimensional change due to a change in temperature and humidity is small, and handleability and low-energy perforation are improved. g, more preferably 30 to 50 J / g.

The crystal melting temperature [Tm] of the heat-sensitive stencil film of the present invention is preferably 200 ° C. or lower, more preferably 190 ° C. or lower, and further preferably 170 ° C. or lower. By setting the crystal melting temperature to 200 ° C. or less,
This is preferable because a molten portion serving as a drilling start point is easily formed and drilling sensitivity is improved. Further, depending on the composition of the film is a blend, for example, if there is a shoulder or a plurality of peaks, at least the shoulder or peak on the lowest temperature side is preferably in the above range, all shoulders or More preferably, the peak satisfies the above range.

The glass transition temperature [Tg] of the heat-sensitive stencil film of the present invention is preferably 55 to 100 ° C, more preferably 60 to 95 ° C. Glass transition temperature 55
It is preferable to set the temperature to -100 ° C because the dimensional stability and the perforation sensitivity are improved.

The heat-sensitive stencil master of the present invention comprises a film and a porous support bonded to each other.

The porous support is not particularly limited, but natural fibers such as manila hemp, pulp, mitsumata, mulberry, Japanese paper, and polyethylene which do not substantially undergo thermal deformation under heating conditions under which the film is perforated. Polyesters such as terephthalate, polyolefins, synthetic fibers such as nylon, metal fibers, glass fibers, etc., which are used alone or as a mixture, and have a structure that has voids or through holes through which printing ink can pass. Examples include thin paper, non-woven fabric, woven fabric, screen gauze, and the like.

The basis weight of the porous support bonded to the heat-sensitive stencil film of the present invention is from 1 to 20 in view of printability.
g / m ² is preferred. More preferably, 2 to 16 g /
m ² , 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. Further, when the basis weight is 1 g / m ² or more, the ink has good holding properties and can be an excellent master 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 porous 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 heat-sensitive stencil film and the heat-sensitive stencil master of the present invention can be produced, for example, by the following method.

First, the polymer mainly composed of polylactic acid in the present invention can be obtained by the following method. As a raw material, a lactic acid component of L-lactic acid or D-lactic acid can be mainly used, and hydroxycarboxylic acids such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid and hydroxycaproic acid can be used in combination. Also, cyclic ester intermediates of these hydroxycarboxylic acids, for example, lactide,
Glycolide or the like can also be used as a raw material. Further, dicarboxylic acids, glycols and the like can also be used.

The polymer mainly composed of polylactic acid can be obtained by a method of directly dehydrating and condensing the above raw materials or a method of ring-opening polymerization of the above cyclic ester intermediate. For example, when produced by direct dehydration condensation, lactic acid or lactic acid and hydroxycarboxylic acid preferably organic solvent,
In particular, the azeotropic dehydration and condensation in the presence of a phenyl ether-based solvent, particularly preferably by removing the water from the azeotropically distilled solvent to remove the water and returning the substantially anhydrous solvent to the reaction system to carry out polymerization, whereby the polymerization is carried out. A polymer of molecular weight is obtained.

A cyclic ester intermediate such as lactide formed when a low molecular weight polymer is depolymerized at high temperature under reduced pressure is subjected to ring-opening polymerization under reduced pressure using a catalyst such as tin octylate to obtain a high molecular weight polymer. It is known that polymers can be obtained.

At this time, a method for adjusting the conditions for removing water and low molecular weight compounds during heating and refluxing in an organic solvent, a method for deactivating the catalyst after the completion of the polymerization reaction to suppress the depolymerization reaction, and By using a heat treatment method, a polymer having a small amount of lactide can be obtained.

The molecular weight of the polymer is preferably in the range of 10,000 to 1,000,000 from the viewpoint of moldability as a film. It is more preferably from 100,000 to 500,000, and still more preferably from 120,000 to 300,000.

In the polymer mainly composed of polylactic acid of the present invention, polyglycolic acid and polybutyric acid containing a hydroxycarboxylic acid component as a constituent component as long as the content of the polylactic acid component is 50% by weight or more. , Polyhydroxybutyrate and the like, polyethylene terephthalate and polyethylene-
2,6-naphthalate, polybutylene terephthalate,
Polyesters such as polyhexamethylene terephthalate, polyethylene isophthalate, polycyclohexane dimethylene terephthalate, and polybutylene succinate, or blends with copolymers mainly containing these polyesters may be used. In the case of a copolymer,
It may be a random copolymer or a block copolymer.

Further, the polylactic acid component of the present invention contains 50
The polymer having less than the weight% can be obtained by the same raw material and method as the above-mentioned polymer mainly composed of polylactic acid. At this time, as long as the amount of the polylactic acid component is less than 50% by weight, for example, copolymers or blends with various polymers such as polyesters other than polylactic acid, or polymers other than polylactic acid alone or in combination of two or more may be used. These can be used in combination.

The polymer used in the heat-sensitive stencil printing film of the present invention may contain, if necessary, a flame retardant, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a crystal nucleating agent, a pigment, a plasticizer. And an organic lubricant such as a terminal blocking agent, a fatty acid ester or a wax, or an antifoaming agent such as a polysiloxane.

Furthermore, lubricity can be imparted according to the purpose. The method of imparting lubricity is not particularly limited, but, for example, clay, mica, titanium oxide, calcium carbonate, calcium phosphate, kaolin, talc,
Examples include a method of blending inorganic particles such as alumina, zirconia, spinel, and wet or dry silica, organic particles having acrylic acid-based polymers, polystyrene, and the like as components, and a method of applying a surfactant. The amount of the particles to be blended is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the polymer. The average diameter of the particles to be blended is 0.01 to 3
μm is preferred, and more preferably 0.1 to 2 μm. Such particles may be used in combination of plural kinds having different types and average diameters.

The heat-sensitive stencil film of the present invention can be obtained by stretching using the above-mentioned polymer. For example, the method of biaxial stretching is biaxial stretching by any of inflation simultaneous biaxial stretching, Stenter simultaneous biaxial stretching, and Stenter sequential biaxial stretching. From the viewpoint of thickness uniformity, a film formed by a stenter sequential biaxial stretching method is preferable.

The heat-sensitive stencil film of the present invention can be produced by the following method using the above-mentioned polymer. After the polymer is sufficiently dried, it is fed to an extruder, melted at 150 to 250 ° C., co-extruded from dies adjacent to each other, laminated and fused, and extruded on a casting drum to obtain an unstretched film.
At this time, the drying condition of the polymer is 10T at a glass transition temperature of the polymer of -30 ° C. or higher and a melting point of 10 ° C. or lower for the purpose of removing water, lactide and low molecular weight substances in the polymer.
It is preferable to reduce the pressure to not more than orr and carry out the reaction for 3 hours or more.
It is more preferable to reduce the pressure to 5 Torr or less and perform the treatment 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, because it suppresses an increase in low molecular weight products due to decomposition.

As a method of forming a laminated structure in the present invention, a method in which two or more extruders are used to combine respective polymers in a T-die at the time of melt extrusion or a film obtained using each polymer is laminated and laminated. Although there are methods etc., from the point that the flatness of the obtained laminated film and the adhesion state are good, two or more extruders, lamination in a molten state using a merging block or a manifold and co-extrusion from a die on a slit. The method of obtaining is preferably used.

As a method of adhering to the casting drum, any of an electrostatic application method, an adhesion method utilizing surface tension of water or the like, an air knife method, a press roll method, and the like may be used. As a method for obtaining a film having good flatness and few surface defects, it is particularly preferable to use a contact casting method using surface tension of water or the like or an electrostatic application method. At this time, an unstretched film having a desired thickness can be produced by adjusting the slit width of the die, the discharge amount of the polymer used for the film, and the rotation speed of the casting drum. Next, by simultaneously or sequentially biaxially stretching the unstretched film,
Biaxially stretched films can be produced. In the case of sequential biaxial stretching, the stretching order may be such that the film is oriented in the longitudinal direction, the width direction, or vice versa. Further, in the sequential biaxial stretching, stretching in the longitudinal direction or the width direction can be performed twice or more. The stretching conditions of the film can be appropriately adjusted according to the desired heat shrinkage characteristics, orientation degree, strength, elastic modulus, etc. of the film, and can be carried out by any method. The stretching temperature of the film is preferably lower than the glass transition temperature of the polymer used and not higher than the crystallization temperature, and more preferably the glass transition temperature of the polymer +
20 ° C. or less. Further, the preheating before stretching is preferably performed at a lower temperature equal to or lower than the stretching temperature of the film. The stretching ratio in the longitudinal direction and the width direction of the film can be set to any value in the range of 1.2 to 5.0 times that can set the stretching temperature lower, and is preferably 1.5 times or more. . Either the stretching ratio in the longitudinal direction or the stretching ratio in the width direction may be increased, and may be the same.

Further, after the film is biaxially stretched, heat treatment may be performed for the purpose of improving strength, stability over time, and shrinkage characteristics. This heat treatment can be performed by any method such as in an oven or on a heated roll. The heat treatment temperature is preferably lower than 30 ° C. and lower than the melting point, more preferably 100 ° C. or lower. The heat treatment time can be arbitrarily set, but it is preferable to perform the heat treatment in a shorter time in the range of 1 to 60 seconds, and more preferably 30 seconds or less. The heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction. The heat-treated film may be rapidly cooled to a glass transition temperature or lower after the heat treatment, or may be cooled stepwise.

Further, after the heat treatment step or after the film formation, heat treatment may be performed using an inert gas such as nitrogen or argon for the purpose of reducing lactide.

The heat-sensitive stencil master of the present invention can be prepared by bonding the above-described heat-sensitive stencil film and a porous support.

The bonding between the heat-sensitive stencil film and the porous support may be performed by using an adhesive or the like as long as the film does not hinder the perforation suitability. It is more preferable to perform the bonding under the conditions such as the above because the transmission of the ink is not hindered by the adhesive or the like. More preferably, it is a method of obtaining a non-woven fabric having a low orientation made of a thermoplastic resin on a thermosensitive stencil film by thermocompression bonding and co-stretching in a film production process. The unstretched film and the unstretched nonwoven fabric are integrally stretched in a thermocompression-bonded state, so that the nonwoven fabric serves as a reinforcing member, and has excellent curl resistance and printing durability. It is preferable because of extremely excellent film formation stability. The method of co-stretching is not particularly limited, and is preferably the same as a film stretching method such as a stenter sequential biaxial stretching method.

The heat-sensitive stencil film and the heat-sensitive stencil master of the present invention reduce the dimensional change and the deformation such as curl due to changes in temperature and humidity during the manufacturing process and long-term storage, as long as the effects of the present invention are not impaired. An aging process may be performed for the purpose of performing. As the processing conditions, it is preferable to perform the processing at a processing temperature of 30 to 80 ° C. for about 1 to 100 hours.

The fibers constituting the porous support may be subjected to a chemical treatment such as acid or alkali treatment, a corona treatment, a low-temperature plasma treatment or the like, if necessary, to impart an affinity to the ink. Good.

In the heat-sensitive stencil master of the present invention, a release agent is preferably applied to the film surface in order to prevent fusion with a thermal head or the like. As the release agent, silicone oil, silicone-based resin, fluorine-based resin, surfactant, wax-based release agent and the like can be used. In these release agents, various additives can be used in combination as long as the effects of the present invention are not impaired. For example,
Examples include antistatic agents, heat-resistant agents, antioxidants, organic particles, inorganic particles, pigments, and the like. The release agent may be applied at any stage before or after the film is stretched.

The coating method is not particularly limited, but it is preferable to use a roll coater, a gravure coater, a reverse coater, a bar coater or the like. Before the release agent is applied, the surface to be applied may be subjected to a corona discharge treatment in air or other various atmospheres, if necessary.

[Measurement Method of Characteristics] (1) Film Thickness A film sample was arbitrarily selected at 10 points, cut out in a 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.

(2) Amount of lactide in film A 0.1 g sample of the film was accurately weighed, immersed in methanol, subjected to ultrasonic cleaning at 50 ° C. for 1 hour, and the extract was measured by high performance liquid chromatography (HPLC). did. Separately, the amount of lactide in the film was determined using a calibration curve obtained by measuring and measuring only lactide.

(3) Perforation sensitivity The prepared master was used as RISOGR manufactured by Riso Kagaku Kogyo Co., Ltd.
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 of the perforated area per dot was determined and evaluated. ◎ and ○ are practically usable. ◎: average perforation area is 450 [mu] m ² or more of ○: average perforation area is 300 [mu] m ² or more 450 [mu] m ² less than those △: × an average perforation area is less than 150 [mu] m ² or more 300 [mu] m ^2: an average perforation area is less than 150 [mu] m ² .

(4) Curling property The prepared master was wound around a cylindrical cylinder having a diameter of 1 inch with the film side facing inward, and the master was heated in a 50 ° C. hot air oven.
After processing for 0 minutes, peel off the tube and sample the base paper into a 10 cm square, place it on a flat table with the film side up, measure the height of the sample from the corner, and measure the average value of the four corners Was used to evaluate the curl properties of the base paper. ◎ and ○ are practically usable. ◎: height of 1 cm or less ：: height of 1 cm or more and less than 1.5 cm Δ: height of 1.5 cm or more and less than 2.0 cm ×: height of 2.0 cm or more Stuff.

(5) Evaluation of plate making printing The created master was used for RISOGR manufactured by Riso Kagaku Corporation.
The ink was supplied to the APH "GR377", and the entire plate was printed in black and white in A4 size by a thermal head plate making method (600 dpi). At this time, the energy applied to the thermal head was 17 μJ per dot. The evaluation was made as follows by visual judgment. ◎ and ○ are practically usable.

A. Transportability In each process of plate making, drum plate making, and printing, the following criteria were evaluated.

◎: wrinkles and tears were not generated on the master, and the master could be transported without any problem. ○: wrinkles of less than 1 cm, tears occurred, but could be transported without any problem. Δ: wrinkles of 1 to 3 cm and tears occurred. However, those that could be transported ×: Those that could be transported but had wrinkles or tears of 3 cm or more in the master, or those that could not be transported and were clogged.

B. Printability ：: No white spots at all ○: 1 to 10 white spots ×: 11 or more white spots

(6) Dimensional change The prepared film was sampled into a square of 20 cm in length and width and treated for 50 hours in a thermo-hygrostat adjusted to a temperature of 50 ° C. and a humidity of 50%, and the length of the sample after the treatment was measured. Then, the dimensional change rate was determined from the average value in the longitudinal direction and the width direction. Dimensional change rate (%) = [(length before processing-length after processing)
/ Length before processing] × 100 (7) Quality stability evaluation The prepared master was processed for 50 hours in a thermo-hygrostat adjusted to a temperature of 50 ° C. and a humidity of 50%, and the punching sensitivity of the master after the processing was measured. The curl property was evaluated. Regarding the curl property, a winding process was performed on a cylindrical tube having a diameter of 1 inch in the same manner as in (4) above. Evaluation criteria are (3) above
Perforation sensitivity and (4) Curl properties were the same. ◎ and ○ are practically usable.

[0069]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Polylactic acid dried at 130 ° C. for 10 hours in a vacuum dryer adjusted to a reduced pressure of 1 Torr (weight average molecular weight: 170,000, L-form: D-form ratio = 99: 1)
To 100 parts by weight, 0.3 parts by weight of calcium carbonate particles having an average particle size of 1.0 μm were added, and after mixing, the mixture was supplied to a twin-screw extruder having a different rotation direction, and extruded at 210 ° C. to be pelletized. The obtained pellets were treated at 130 ° C. for 5 hours in a vacuum dryer adjusted to a reduced pressure of 1 Torr to perform crystallization and drying. Separately, a copolyester of ethylene terephthalate and ethylene isophthalate (copolymer molar ratio: 85/15) containing 0.4 parts by weight of cohesive silica particles having an average particle size of 1.5 μm is crystallized, and the pressure reduction degree is 1 Torr.
Drying was performed at 140 ° C. for 3 hours in a vacuum dryer adjusted to r.

Then, using two extruders, the polylactic acid pellets were supplied to extruder A heated to 230 ° C.
Feeding the copolymerized polyester of ethylene terephthalate and ethylene isophthalate to the extruder B heated to
The unstretched laminated film having a thickness of 20 μm (lamination ratio A: B = 90: 10) is cast on a drum cooled to 25 ° C. having a diameter of 300 mm by merging and extruding in a T-die heated to 250 ° C. Was prepared. Next, after stretching 2.5 times in the longitudinal direction between the heating rolls at 75 ° C., it is fed into a tenter type stretching machine and stretched 3.0 times in the width direction at 75 ° C.
Further, it was heat-treated at 75 ° C. for 10 seconds in a tenter to produce a biaxially stretched laminated film having a thickness of 2.0 μm. The lactide content of the film was 0.38%.

Next, the obtained film was bonded to the A layer side surface with a 10 g / m ² basis weight Japanese paper mainly composed of Manila hemp using a vinyl acetate adhesive, and the other surface of the film was coated with silicone. The release agent was applied at 0.05 g / m ² using a bar coater to prepare a heat-sensitive stencil master. Tables 1 and 2 show the evaluation results.

(Example 2) Biaxial stretching was performed in the same manner as in Example 1 except that the laminated structure was three layers of B / A / B (lamination ratio B: A: B = 10: 80: 10). A laminated film was produced. The lactide content of the film was 0.26%.

Then, using a vinyl acetate-based 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.
05 g / m ^{2 was} applied to prepare a heat-sensitive stencil master. Tables 1 and 2 show the evaluation results.

(Example 3) A mixture of polylactic acid and copolymerized polyester as in Example 2 (mixing ratio 1: 9)
A biaxially stretched laminated film was produced in the same manner as in Example 2, except that The lactide content of the obtained film was 0.34%.

Next, using a vinyl acetate-based 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.

Example 4 The layer B was composed of a copolymerized polyester of ethylene terephthalate and ethylene naphthalate (copolymer molar ratio: 85:15), and the layered structure was B / A / B.
(Lamination ratio B: A: B = 5: 90: 5), in the longitudinal direction,
A biaxially stretched laminated film was produced in the same manner as in Example 1, except that the stretching temperature in the width direction and the heat treatment temperature were each set to 85 ° C. The lactide content of the obtained film was 0.1.
30%.

Next, using a vinyl acetate-based adhesive on one surface of the obtained film, a basis weight mainly containing Manila hemp was used.
laminated with g / m ² of paper, further silicone release agent 0.05 g / m ² with a bar coater on the other surface of the film to produce a heat-sensitive stencil printing master. Tables 1 and 2 show the evaluation results.

(Example 5) Polylactic acid 8 used in Example 1
0.3 part by weight of calcium carbonate particles having an average particle size of 1.0 μm was added to 5 parts by weight, 15 parts by weight of a copolymer of poly-3-hydroxybutyric acid and poly-3-hydroxyvaleric acid (copolymerization molar ratio: 92/8). After mixing, the mixture was supplied to a twin-screw extruder and extruded at 210 ° C. into pellets. A biaxially stretched laminated film was produced in the same manner as in Example 2 except that the obtained pellet was used as the layer A. The lactide content of the obtained film was 0.1.
28%.

Next, on one side of the obtained film, using a vinyl acetate-based adhesive, a basis weight 10
laminated with g / m ² of paper, further silicone release agent 0.05 g / m ² with a bar coater on the other surface of the film to produce a heat-sensitive stencil printing master. Tables 1 and 2 show the evaluation results.

(Example 6) 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 give an average fiber diameter of 8 μm and a basis weight of 100.
g / m ² of an unstretched nonwoven fabric was produced.

Separately, an unstretched laminated film was produced in the same manner as in Example 2.

An unstretched nonwoven fabric was overlaid on the obtained unstretched laminated film, supplied to a heating roll, and thermocompression-bonded at a roll temperature of 100 ° C. The thus obtained laminate is stretched 3.0 times in the length direction between heating rolls at 85 ° C., then fed into a tenter type stretching machine, stretched 3.3 times in the width direction at 85 ° C., and further in the tenter. Heat treatment was performed at 85 ° C. to produce a heat-sensitive stencil master having a thickness of 60 μm. At the entrance of the tenter on the film surface of the master, a wax-based release agent was dried using a gravure coater and weighed 0.1 g / m 2.
Applied. The fiber weight of the obtained master is 9 g / m2.
And the average fiber diameter was 4 μm. The thickness of the film alone was 1.7 μm. The lactide content of the film peeled off from the master and measured was 0.35%. Tables 1 and 2 show the evaluation results.

Comparative Example 1 A biaxially stretched laminated film was produced in the same manner as in Example 1 except that the polylactic acid monolayer film used in Example 1 was used. The lactide content of the obtained film was 0.56%.

Then, using a vinyl acetate-based 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.

Comparative Example 2 The procedure of Example 1 was repeated, except that a monolayer film of the copolymerized polyester of ethylene terephthalate and ethylene isophthalate (copolymer molar ratio: 85/15) used in Example 1 was used. A biaxially stretched laminated film was produced. The lactide content of the obtained film was 0
%Met.

Then, using a vinyl acetate adhesive on one side of the obtained film, a basis weight of 10 g mainly composed of Manila hemp
/ 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.

Comparative Example 3 Polylactic acid 6 used in Example 1
0 parts by weight, 10 parts by weight of a copolymer of poly-3-hydroxybutyric acid and poly-3-hydroxyvaleric acid (copolymerization molar ratio: 92/8), a copolymerized polyester of ethylene terephthalate and ethylene isophthalate (copolymerization molar ratio of 85) / 15) 3
0 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.
Extruded pellets at 0 ° C. The obtained pellets were used as layer B, and the layered configuration was B / A / B (layered ratio B: A: B
= 10: 80: 10), to prepare a biaxially stretched laminated film in the same manner as in Example 1. The lactide content of the obtained film was 0.44%.

Next, on one side of the obtained film, using a vinyl acetate adhesive, a basis weight of 10
laminated with g / m ² of paper, further silicone release agent 0.05 g / m ² with a bar coater on the other surface of the film to produce a heat-sensitive stencil printing master. Tables 1 and 2 show the evaluation results.

[0090]

[Table 1]

[0091]

[Table 2]

[0092]

According to the present invention, by forming a laminated film of a polymer layer mainly composed of polylactic acid and a polymer layer containing less than 50% by weight of a polylactic acid component, the piercing property and printability at low energy can be obtained. In addition, it is possible to obtain an excellent heat-sensitive stencil printing film having excellent transportability and little change with time due to the influence of temperature and humidity, and a heat-sensitive stencil master using the same. As a result, it is possible to extend the life of the thermal head and the printing press, shorten the time required for plate making, increase the definition of printed matter, and stabilize the quality of the film and master.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 67:00 C08L 67:00 F term (Reference) 2H114 AB22 AB25 BA01 BA05 BA10 DA41 DA56 DA64 EA02 EA10 FA01 FA06 4F071 AA43 AA43X AF54Y AH12 BC01 BC02 BC12 CA08 4F210 AA24 AE01 AG01 AG03 AH81 QA02 QA03 QC06 QG01 QG15 QG18

Claims (7)

[Claims] 1. A heat-sensitive stencil film comprising a laminated film of a polymer layer mainly composed of polylactic acid and a polymer layer containing less than 50% by weight of a polylactic acid component. 2. An environment having a temperature of 50 ° C. and a humidity of 50%.
2. The heat-sensitive stencil printing film according to claim 1, wherein a dimensional change upon time treatment is less than 3%. 3. The heat-sensitive stencil film according to claim 1, wherein the lactide content is 0.5% by weight or less. 4. The heat-sensitive stencil film according to claim 1, which has a thickness of 0.2 to 8 μm. 5. The heat-sensitive stencil film according to claim 1, wherein the polymer layer containing less than 50% by weight of the polylactic acid component is made of polyester or polyester and polylactic acid. . 6. A heat-sensitive stencil master comprising the laminated film according to claim 1 and a porous support. 7. The heat-sensitive stencil master according to claim 6, wherein the laminated film and the porous support are bonded substantially without an adhesive.