JPH09123633A - Thermosensitive stencil printing stencil paper and film therefore - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide superior perforation sensitivity and improve an image resolving degree at the time of printing, print quality and plate wear. SOLUTION: This film used for a thermosensitive stencil printing stencil paper is a biaxially stretched polyester film consisting of different types of polyester such as (A) polyethylene terephthalate polyester, (B) polyhexamethylene terephthalate polyester and (C) polybutylene terephthalate polyester contained at such a mixing ratio as to meet the relationship given below. In addition, the coefficient of heat contraction of the film at 150 deg.C is at least, 30%. 35<=a<=65, 15<=b<=45, 0<=c<=45. a is the ratio of (A) component (wt.%), b is the ratio of (B) component (wt.%) and c is the ratio of (C) component (wt.%).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat-sensitive stencil printing base paper and a film used for the same. More specifically, the invention relates to a heat-sensitive stencil printing base paper having excellent perforation sensitivity, improved resolution (gradation) during printing, printing quality and printing durability (printing durability), and a film used therefor.

[0002]

2. Description of the Related Art Conventionally, as a heat-sensitive stencil printing base paper which is perforated by pulse irradiation with a xenon flash lamp, a thermal head or a laser beam, a heat-sensitive stencil printing base paper and a porous thin-film support are used. Has been. As the film for heat-sensitive stencil printing paper, vinyl chloride-vinylidene chloride copolymer film, polypropylene film, polyethylene terephthalate copolymer film, etc. are used, and as the porous thin leaf support, thin paper, polyester (polyethylene film) is used. (Terephthalate) gauze is used.

Further, in recent years, it has been proposed to use the film itself for heat-sensitive stencil printing paper as a heat-sensitive stencil printing base paper (supportless heat-sensitive stencil printing base paper) without using a porous thin-film support (Japanese Patent Laid-Open No. Hei 5). -185574 and JP-A-5-220919). As a specific example of this film, a biaxially stretched film made of ethylene terephthalate-cyclohexane dimethylene terephthalate copolyester is shown.

Such a film for heat-sensitive stencil printing base paper contains
The following characteristics are required. (1) The thermal perforation sensitivity is good. That is, it must have a sufficient heat shrinkage ratio so that it can be melted with a small amount of heat and a perforation of an appropriate size that makes an image at the time of printing clear can be obtained. If the thermal perforation sensitivity is good, there are advantages such as shortening the plate making time and extending the life of the xenon flash lamp and the thermal head because less energy is required. (2) It should have a strength and elastic modulus sufficient to withstand the work of laminating with a porous thin-film support and printing. Also,
In such work, even if there is a heating step, problems such as remarkable curling of the base paper will not occur due to the influence of the heating step. (3) The gradation of thermal perforation is good. When used as a base paper, if the portion other than the portion to be perforated is melted due to the influence of the perforations in the periphery, the gradation of the printed image becomes inferior, which is not preferable. That is, it has a thermal perforation property that can clearly distinguish the perforated part and the non-perforated part.

In addition to these requirements, it is preferable that the film is excellent in productivity at the time of film production. Specifically, the film has good stretchability and does not cause troubles such as breakage.
Further, the winding property and the slit property are also good, and it is preferable that wrinkles do not occur and winding deviation does not occur during winding.
From this point of view, it is a biaxially stretched film, and the film for heat-sensitive stencil printing base paper has improved printing characteristics by defining its thermal characteristics (see Japanese Patent Laid-Open No. 62-149496).
A film for heat-sensitive stencil printing base paper (see Japanese Patent Application Laid-Open No. 62-282983) has been proposed in which heat shrinkage characteristics are specified, but it does not fully satisfy all the above requirements. In particular, the film for a supportless heat-sensitive stencil printing base paper itself needs to exhibit the function of a support,
Higher thermal perforation sensitivity and gradation are required.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a film for heat-sensitive stencil printing base paper which is excellent in perforation sensitivity and has improved printing resolution, printing quality and printing durability. Another object of the present invention is to provide a heat-sensitive stencil printing base paper obtained by laminating a film for heat-sensitive stencil printing base paper, which has excellent perforation sensitivity, resolution during printing, printing quality, and printing durability, with a porous thin leaf support. To provide. Still another object of the present invention is excellent in perforation sensitivity, resolution during printing, print quality,
It is an object of the present invention to provide a supportless heat-sensitive stencil printing base paper which is composed only of a film for heat-sensitive stencil printing base paper having improved printing durability. Still other objects and advantages of the present invention will become apparent from the following description.

[0007]

The above objects and advantages of the present invention are, according to the present invention, a biaxially stretched polyester film, wherein the polyester constituting the film is (A) polyethylene terephthalate-based polyester. ,
(B) Polyhexamethylene terephthalate-based polyester and (C) Polybutylene terephthalate-based polyester are represented by the following formulas (1) to (3).

35 ≦ a ≦ 65 (1) 15 ≦ b ≦ 45 (2) 0 ≦ c ≦ 45 (3)

Here, a is a ratio of component (A) (% by weight), b is a ratio of component (B) (% by weight), and c is a ratio of component (C) (% by weight). A heat-sensitive stencil printing base paper film characterized in that the heat shrinkage ratio of the film at 150 ° C. is 30% or more.

The heat-sensitive stencil printing base paper used in the present invention is, as described above, perforated and made by receiving heat from pulse irradiation of a xenon flash lamp, a thermal head, a laser beam or the like. There are those which use the film itself (supportless heat-sensitive stencil printing base paper) and those in which a film for heat-sensitive stencil printing base paper and a porous thin film support are laminated. The heat-sensitive stencil printing base paper film (hereinafter, also referred to as a heat-sensitive film) forms a portion in which characters and the like of the base paper to be printed are perforated when exposed to flash light or the heat of the thermal head.

In the present invention, the polyester constituting the biaxially stretched film includes (A) polyethylene terephthalate (hereinafter abbreviated as PET) type polyester and (B).
It comprises a specific proportion of polyhexamethylene terephthalate (hereinafter abbreviated as PHT) polyester, or a specific proportion of these and (C) polybutylene terephthalate (hereinafter abbreviated as PBT) polyester.

The PET-based polyester is a polymer in which at least 70 mol% of the polymer constituent units are composed of ethylene terephthalate units, and also includes a copolymer modified with 30 mol% or less of the third component based on the total acid component. To do. Similarly, the PHT-based polyester is a polymer in which at least 70 mol% of the polymer constituent units are composed of hexamethylene terephthalate units, and also includes a copolymer modified with 30 mol% or less of a third component based on all acid components. To do. The PBT-based polyester means at least 70 of the polymer constitutional units.
A polymer in which mol% is composed of butylene terephthalate (tetramethylene terephthalate) units,
Also included are copolymers modified with up to 30 mol% of the third component, based on total acid component.

These polyesters are generally obtained by reacting terephthalic acid or a functional derivative thereof (for example, a di-lower alkyl ester such as dimethyl ester) with an alkylene glycol (ethylene glycol, hexamethylene glycol or tetramethylene glycol), and further reacting them. It is produced by polycondensing the product. It can also be produced by a method such as polycondensing a dialkylene glycol ester of terephthalic acid. These reactions are preferably carried out in the presence of conventionally known catalysts.

Specific examples of the third component for modifying these polyesters include aromatic dicarboxylic acids other than terephthalic acid (for example, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketone). Dicarboxylic acid, sodium sulfoisophthalic acid, etc.), alicyclic dicarboxylic acid (eg, decalin dicarboxylic acid, hexahydroterephthalic acid, etc.), aliphatic carboxylic acid (eg, malonic acid, succinic acid, adipic acid, etc.), aliphatic diol (For example, ethylene glycol (excluding PET-based polyester), trimethylene glycol,
Tetramethylene glycol, (except for PBT type polyester), pentamethylene glycol, hexamethylene glycol (except for PHT type polyester), neopentylene glycol, diethylene glycol, etc., alicyclic diol (for example, cyclohexane diol, Cyclohexanedimethanol, etc., aromatic diols (eg, hydroquinone, catechol, resorcin, bisphenol A, tetrabromobisphenol A, dihydroxyethoxybisphenol A, bisphenol S, dihydroxymethoxybisphenol S, dihydroxyethoxybisphenol S, 3,3′-dimethyl) -4,4'-dihydroxydiphenyl sulfone, 3,
3'5,5'-tetramethyl-4,4'-dihydroxydiphenyl sulfone, etc.), aliphatic oxycarboxylic acid (eg, glycolic acid, hydroacrylic acid, 3-oxypropionic acid, etc.), alicyclic oxycarboxylic acid (For example, asiatic acid, quinobaic acid, etc.), aromatic oxycarboxylic acid (for example, salicylic acid, m-oxybenzoic acid, p-oxybenzoic acid, mandelic acid, matrolactic acid, etc.) can be exemplified.

Further, a polyfunctional compound having a functionality of 3 or more, such as glycerin, trimethylolpropane, pentaerythritol, etc., within the range where the polyester is substantially linear.
Trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, gallic acid or the like may be copolymerized, or a monofunctional compound such as o-benzoylbenzoic acid or naphthoic acid may be reacted.

Such a polyester has an absorption peak in the wavelength range of, for example, an antioxidant, a heat stabilizer, a lubricant, a surfactant, an antistatic agent, a conductive agent, a dye, a lubricant, and flash irradiation light, if necessary. You may add additives, such as an agent (light absorber). The intrinsic viscosity of the PET-based polyester (A) is
It is preferably 0.4 or more, more preferably 0.5 to 1.0. The intrinsic viscosity of the PHT polyester (B) is preferably 0.4 or more, more preferably 0.5 to 1.0. In addition, the intrinsic viscosity of PBT polyester (C) is
It is preferably 0.6 or more, and more preferably 0.8 to 1.3. If these intrinsic viscosities are too small, the physical properties of the film will be insufficient.

The polyester constituting the biaxially stretched film in the present invention is, as described above, (A) PET type polyester, (B) PHT type polyester and (C).
Although it is made of PBT-based polyester, the ratio of these components must satisfy the following formulas (1) to (3).

35 ≦ a ≦ 65 (1) 15 ≦ b ≦ 45 (2) 0 ≦ c ≦ 45 (3)

Here, a is the ratio (% by weight) of the component (A), b is the ratio (% by weight) of the component (B), and c is the ratio (% by weight) of the component (C).

(A) Ratio of PET polyester (a:
(Wt%) is preferably 38 or more and 62 or less, and particularly preferably 41 or more and 59 or less. This ratio (a:% by weight)
Is less than 35, the perforation sensitivity is lowered and wrinkles are produced, which is not preferable. On the other hand, if this ratio (a:% by weight) is larger than 65, the perforation sensitivity becomes insufficient and the printing quality deteriorates, which is not preferable.

(B) Ratio of PHT type polyester (b:
(Wt%) is preferably 18 or more and 45 or less, and particularly preferably 21 or more and 39 or less. By using the PHT-based polyester, the perforation sensitivity, gradation and the like are further improved, and the properties required for the baseless thermosensitive stencil printing base paper can be particularly satisfied. If this ratio (b:% by weight) is less than 15, the perforation sensitivity is lowered, the printing quality is deteriorated, and plate-making wrinkles occur, which is not preferable. on the other hand,
If this ratio (b:% by weight) is greater than 45, poor kneading of the polymer easily occurs, making it difficult to form a stable film, which in turn deteriorates the film forming property and productivity of the film.
In addition, it is not preferable because it does not have sufficient mechanical strength and solvent resistance as a film, cannot withstand workability during coating, laminating or printing, and causes wrinkles during plate making.

(C) Ratio of PBT type polyester (c:
%) Is preferably 3 or more and 42 or less, particularly preferably 6 or more and 39 or less. The use of this PBT-based polyester improves the mixing property of the PET-based polyester and the PHT-based polyester, especially the melt-kneading property, and also improves the perforation sensitivity. If this ratio (c:% by weight) is greater than 45, the perforation sensitivity may be insufficient, possibly due to the easily crystallizing property of the PBT-based polyester, and the heat shrinkage stress may increase to cause plate wrinkling, which is not preferable.

PET-based polyester, PH in the film
The amounts of the T-based polyester and PBT-based polyester components are CF ₃ COOD: CDCl ₃ =
After dissolution in a 1: 1 mixed solvent, ¹ H-NMR measurement is carried out, and after assigning each peak, it can be determined from the integrated intensity of ¹ H.

The polyester in the present invention is obtained by melt-kneading the above-mentioned (A) PET-based polyester and (B) PHT-based polyester, or (C) PBT-based polyester, or by dissolving and mixing them in a solvent. it can. This kneading is usually performed during film formation.
Further, the kneading may be performed in advance before the film formation. In this melt-kneading, the reaction of each component usually proceeds to form a block copolymer, and further a random copolymer, but in the present invention, before the random copolymer is formed, the melt is melted. It is necessary to stop kneading. Otherwise, there is no point in melting and kneading the components. In other words, it should be understood that melt kneading is allowed until substantially the block copolymer is formed. Therefore, those obtained by melt-kneading these components include those obtained by substantially converting the mixture (composition) in which each component is uniformly mixed into a block copolymer. Then, depending on the amount ratio of each component, when the melt-kneaded product is mainly or substantially composed of the block copolymer, one melting peak is observed.

The polyester in the present invention may contain a third component (other thermoplastic polymer) other than the above-mentioned (A) PET type polyester, (B) PHT type polyester and (C) PBT type polyester component. In this case, the amount of the third component is 20% by weight or less, further 15
It is preferably not more than 10% by weight, particularly preferably not more than 10% by weight. If the amount of this third component exceeds 20% by weight, PET
The excellent physical properties inherent to the polyesters, PHT-based polyesters and PBT-based polyesters are impaired, and the effect of heat piercing property is not sufficiently obtained, which is not preferable. As the third component, for example, polyethylene,
Examples thereof include polystyrene, polysulfone, polyphenylene sulfide, polyamide and polyimide.

In the present invention, the polyester film must be biaxially stretched, and non-stretched or uniaxially stretched film causes perforation unevenness, and lacks unevenness even after printing. The degree of biaxial stretching is not particularly limited, but a plane orientation coefficient of 0.90 to 0.98 is preferred for the present invention.

The biaxially stretched polyester film has 1
The heat shrinkage rate at 50 ° C. is 30% or more. It is preferably at least 35%, more preferably at least 40%. However, this heat shrinkage rate is represented by the average value of the heat shrinkage rate in the vertical and horizontal directions of the film. If the heat shrinkage ratio is less than 30%, the perforation tends to be non-uniform, the resolution may be deteriorated, and the perforation sensitivity may be insufficient, which is not preferable. The heat shrinkage ratio at 150 ° C. preferably does not exceed 60%. If the heat shrinkage ratio exceeds 60%, the print quality is deteriorated and plate-making wrinkles are generated, which is not preferable.

As can be understood from the above-mentioned melt-kneading, the biaxially stretched polyester film may have two or more melting peaks or a single melting peak observed in the DSC temperature rising measurement. But it's okay. The temperature of this melting peak is preferably 260 ° C. or lower, more preferably 245 ° C. or lower, and particularly preferably 230 ° C. or lower.
C. or higher, more preferably 105.degree. C. or higher, and particularly preferably 120.degree. C. or higher. When the melting peak temperature is higher than 260 ° C., the piercing property becomes insufficient and the sensitivity becomes poor, which is not preferable. On the other hand, if it is lower than 90 ° C,
The polymer softened during perforation tends to adhere to the thermal head, which causes a problem in print quality and causes sticking (or sticking) of a document during perforation by flash light irradiation, which is not preferable. When two or more melting peaks are observed, it is preferable that the melting peak temperature on the highest temperature side satisfies the upper limit and the melting peak temperature on the lowest temperature side satisfies the lower limit.

The glass transition temperature (Tg) of the biaxially stretched polyester film is 25 ° C. or higher, and further 30 ° C.
As described above, it is particularly preferable that the temperature is 35 ° C. or higher. When the glass transition temperature is less than 25 ° C., the film is not easily handled, curling is likely to occur in the step of preparing the base paper, and the quality of the film changes with time, which is not preferable. In addition, 2
When three or more glass transition temperatures are observed, the lowest one should satisfy the above temperature.

The biaxially stretched polyester film of the present invention has a total melting energy (ΔHu) of 17 to 50 Joules (J) / g, further 21 to 46 J / g, and particularly 25 to.
It is preferably 42 J / g. When the total melting energy is less than 17 J / g, the polymer is apt to stick to the thermal head or the original (sticking), and it is difficult to obtain sufficient mechanical strength and solvent resistance. It is not preferable because the workability during printing tends to be unbearable. On the other hand, if it exceeds 50 J / g, it is not preferable because sufficient perforation is difficult to obtain, a character with a missing portion is formed, or the sensitivity is poor.

The biaxially stretched polyester film has a Young's modulus of 250 kg / mm ² or more, further 300 kg / mm ^2.
mm ² or more, particularly 350 kg / mm ² or more,
It is preferable because the workability and printing durability of the stencil sheet are improved. However, this Young's modulus is represented by the average value of Young's modulus in the vertical and horizontal directions.

The biaxially stretched polyester film is used for improving transportability, windability, coating at the time of making base paper, workability at the laminating step and printing, or at the time of thermal perforation, the thermal head and film are used. In order to prevent the fusion of the above, it is preferable that the surface is roughened to provide appropriate slipperiness. As for the degree of surface roughening, the center line average roughness (Ra) is 0.015 to 0.5 μm, and further 0.02.
It is preferably about 0.3 μm. As the surface-roughening agent, 0.1 to 5.0% by weight, preferably 0.1 to 3.0% by weight, of fine particles having an average particle size of 0.05 to 2.0 μm in the film.
It is preferable to include them. The fine particles may be internally precipitated particles or externally added particles.

Examples of externally added particles include calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, calcium phosphate, lithium phosphate, magnesium phosphate, lithium fluoride, aluminum oxide, silicon oxide (silica), titanium oxide. , Kaolin, talc, carbon black, silicon nitride, boron nitride, crosslinked polymer particles (eg, crosslinked polystyrene,
Examples thereof include fine particles of crosslinked acrylic resin, crosslinked silicone resin and the like. These may be used alone,
Further, two or more kinds may be used in combination. Among these, those having a sharp particle size distribution and spherical particles are preferable, and spherical silica particles are particularly preferable. Here, the term "spherical" means that the ratio of major axis / minor axis is 1.0 to 1.2.

As a method of incorporating such a surface-roughening agent, an internal particle deposition method in which an alkali (earth) metal compound is deposited as fine particles by adding a phosphorus compound during polyester production, or a film formation from a polymer production step An external particle addition method in which inert inorganic or organic fine particles are added to the polymer in any one of the steps is included.

The biaxially stretched polyester film has an average surface air layer thickness (Rp) of 2.2 to 5.0 μm.
m, more preferably 2.4 to 4.5 μm, and particularly 2.6 to 4.0 μm, in order to prevent sticking with the thermal head and improve the holding power of the overcoat layer.

The biaxially stretched polyester film according to the present invention can be manufactured according to a conventionally known method. For example, after sufficiently drying each polyester under predetermined conditions, the polyester is supplied to a well-known melt extrusion apparatus typified by an extruder, and the temperature is not lower than the polymer melting point (Tm: ° C.), particularly in the range of Tm to (Tm + 70) ° C. Heat to melt. In this extrusion step, each polyester is melt-kneaded uniformly and the degree of melt-kneading is adjusted. Next, the melt-kneaded polymer is extruded into a sheet from a slit die and rapidly cooled and solidified on a rotating cooling drum to obtain a substantially amorphous unstretched (oriented) sheet. In this case, the electrostatic charge application contact method and / or the liquid coating contact method are preferably adopted in order to enhance the adhesion to the rotary cooling drum and improve the surface flatness (flatness and smoothness) of the sheet.

The electrostatic charge application contact method is a method in which a DC voltage is applied to a linear electrode stretched in a direction orthogonal to the flow of a sheet extruded from a die to apply an electrostatic charge to the surface (non-drum side) of the sheet. This is a method of improving the adhesion between the sheet and the rotating cooling drum by this action. The liquid application contact method is a method in which the liquid is evenly applied to all or part of the surface of the rotary cooling drum (for example, the part in contact with both ends of the sheet).
This is a method of improving the adhesion between the sheet and the rotary cooling drum. In the present invention, an inflation casting method or a casting method may be employed as a method of producing a substantially amorphous unstretched (oriented) sheet by using both in combination, if necessary.

The unstretched (oriented) sheet thus obtained is then stretched biaxially to give a biaxially stretched film. This stretching method includes sequential biaxial stretching method (tenter method) and simultaneous biaxial stretching method (tenter method or tube method).
Can be used. As the stretching conditions in the sequential biaxial stretching method, the unstretched sheet is (Tg-10) to (Tg +).
70) ° C. (where Tg is the highest glass transition temperature of the unstretched sheet), preferably 2 to 6 times, more preferably 2.5 to 5 times in one direction (longitudinal direction or transverse direction).
Tg-in the direction orthogonal to the first stage (when the first stage stretching is the longitudinal direction, the second stage stretching is the transverse direction) after stretching 5 times.
At a temperature in the range of (Tg + 70) ° C., preferably 2 to 6 times,
More preferably, it is stretched 2.5 to 5.5 times. The unidirectional stretching may be carried out in a multi-stage method of two or more stages, but in this case as well, it is desirable that the final stretching ratio is within the above range. In addition, after the second stage stretching, intermediate heat treatment may be performed, and then stretching may be performed again in the same direction as the first stage and / or in the same direction as the second stage. Further, the unstretched sheet can be simultaneously biaxially stretched so that the area ratio is preferably 6 to 30 times, more preferably 8 to 25 times.

The biaxially stretched film thus obtained is heat-treated as necessary, but this treatment is carried out under the condition that the heat shrinkage rate is 30% or more. To obtain this heat shrinkage ratio, (T
It is preferable to perform heat treatment for 1 second to 10 minutes at a temperature in the range of g) to (Tg + 100) ° C. (where Tg is the highest glass transition temperature). At that time, the shrinkage may be limited to 20% or less, or may be performed under a fixed length, or may be performed in two or more steps.

The thickness of the thus obtained biaxially stretched polyester film is preferably 0.2 to 10 μm, but when it is used by laminating with a support, it is 0.2 to 7 μm, further 0.5 to 5 μm, and especially 0. It is preferable that the thickness is 0.9 to 3.5 μm. Moreover, when a support is used, that is, when used without a support, it is 1.5 to 10 μm, further 2 to 7 μm
The thickness is preferably m, particularly 3 to 5 μm. If the thickness of the film is too thin, it becomes difficult to bond it to the support, and it tends to be unclear during printing, and uneven density tends to occur, and printing durability tends to decrease, while if it is too thick, perforation sensitivity decreases. It is not preferable because it is easy to cause a missing portion or thick spots.

In one embodiment of the present invention, the biaxially stretched polyester film (heat-sensitive film) and a porous thin-film support are laminated to form a heat-sensitive stencil printing base paper. In this aspect, the strength and handleability of the support can be expected to be improved, and therefore the thickness of the film can be reduced,
And the low thermal conductivity of the support enhances the efficiency of the drilling energy. The porous thin leaf support is not particularly limited, but representative examples thereof include Japanese paper, standard paper, synthetic fiber paper, various woven fabrics, and non-woven fabrics.
The basis weight of the porous thin leaf support is not particularly limited,
20 g / m ² approximately, it is preferably further 5 to 15 g / m ² approximately. In the case of a mesh sheet, 20
Woven fibers having a thickness of -60 μm, and a lattice spacing of 20-250 μm are preferable.

The adhesive used to bond the heat-sensitive film and the porous thin-film support to each other is not particularly limited.
Representative examples include vinyl acetate resin, acrylic resin, urethane resin, and copolyester resin.
In another embodiment of the present invention, the biaxially stretched polyester film (heat-sensitive film) alone is used as a heat-sensitive stencil printing base paper (support-less heat-sensitive stencil printing base paper) without using a porous thin leaf support. In this aspect, the film itself is required to have strength as a base paper, handleability, etc., and further perforation sensitivity due to the thermal conductivity of the film (escape of perforation thermal energy), but the biaxially stretched polyester film is Demonstrate the feature of being able to comply with. This base paper is excellent in perforation sensitivity and gradation, and can form a clearer image than the holes which are perforated discontinuously in a dot shape by flash plate making or thermal head plate making. A plate-making method using a supportless heat-sensitive stencil printing base paper is disclosed in JP-A-5-185574.
It is disclosed in Japanese Patent Laid-Open No. 5-220919.

When the heat-sensitive stencil printing base paper of the present invention is used for making a thermal head, it is preferable that the side of the heat-sensitive film which comes into contact with the thermal head is subjected to a heat fusion preventing treatment.
As this treatment method, a fatty acid metal salt, a phosphoric acid ester type surfactant, a fluid lubricant such as silicone oil, and a heat fusion inhibitor such as a fluorine compound having a perfluoroalkyl group are uniformly applied and heat fused. The method of providing an adhesion prevention layer is mentioned. The coating amount is preferably 0.001 to ² g / m ² , and more preferably 0.005 to 1 g / m ² .

The heat-sensitive stencil printing base paper of the present invention may be subjected to antistatic treatment. Examples of this treatment method include a method of uniformly applying an antistatic agent or a conductive agent to the heat-sensitive film, and a method of adding an antistatic agent or a conductive agent to the heat-sensitive film. As an antistatic agent in the coating method,
Examples thereof include general antistatic agents such as organic sulfonic acid metal salts, polyalkylene oxides, esters, amines, polyethoxy derivatives, carboxylates, ammine anidine salts, quaternary ammonium salts and alkyl phosphates. The coating amount of the antistatic agent, 0.001~2g / m ^2, further 0.01 to 0.5 g / m ² is preferred. Examples of the antistatic agent in the addition-containing method include organic sulfonic acid metal salts, polyalkylene oxides, quaternary ammonium salts, and the like. The added content of the antistatic agent depends on the kind, but in the case of an organic sulfonic acid metal salt, it is 0.1 to
2% by weight, preferably 0.2 to 1.5% by weight, and in the case of polyalkylene oxide, 0.1 to 5% by weight, more preferably 0.05% by weight.
2 to 4% by weight is preferable. The content of the conductive agent added depends on its type, but is, for example, 1 to 50% by weight, and further 2 to 3%.
0% by weight is preferred.

The organic sulfonic acid metal salt has the following formula

R ¹ SO ₃ X

(Wherein R ¹ is an aliphatic group, an alicyclic group or an aromatic group, and X is a metal such as Na, K or Li). Specific examples thereof include metal salts of alkyl sulfonic acid and metal salts of alkylbenzene sulfonic acid. Preferred examples of the alkyl group include higher alkyl groups such as octyl, decyl, dodecyl (lauryl), tetradecyl (myristyl), hexadecyl, octadecyl (sterial). More specific compounds include Na lauryl sulfonate, K lauryl sulfonate, L lauryl sulfonate.
Examples include i, Na stearyl sulfonate, K stearyl sulfonate, Li stearyl sulfonate, Na dodecyl benzene sulfonate, K dodecyl benzene sulfonate, Li dodecyl benzene sulfonate, and the like.

Examples of the polyalkylene oxide include polyethylene oxide, polypropylene oxide, polyethylene oxide-propylene oxide copolymer, polytetramethylene oxide and the like. The molecular weight of these is preferably 400 to 500,000, and more preferably 1000 to 50,000. As the conductive agent, the following formula

[R ² --N (CH ₃ ) ₂ --R ³ ] X

(Wherein R ² is an alkyl group having 12 to 18 carbon atoms, R ³ is an alkyl group having 12 to 18 carbon atoms or a methyl group, and X is Cl or Br). Examples include salt. Examples of this alkyl group include dodecyl (lauryl), tetradecyl (myristyl), hexadecyl, octadecyl (sterial) and the like.

[0051]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Various physical properties and characteristics in the present invention are measured and defined as follows. (1) Intrinsic viscosity [η] A value (unit: 100 cc / g) measured at 25 ° C using o-chlorophenol as a solvent.

(2) Surface orientation coefficient Refractive index (Nz) in the thickness direction of the film and the film is kept at a temperature 50 ° C. higher than the melting point for 5 minutes (however, it is sandwiched between glass plates so that the surface does not become uneven), After that, this sample is rapidly cooled, taken out from between the glass plates, and the refractive index (Nz ₀ ) in the thickness direction is calculated and calculated by the following formula.

Plane orientation coefficient = Nz / Nz ₀

An Atsube refractometer is used to measure the refractive index.

(3) Melting peak temperature Tmp (° C) [T
mp (min, ..., Tmp (max))] 10 mg of film is set in a thermal analysis system SSC / 5200, DSC220 manufactured by Seiko Instruments Inc.,
The film is heated in a N ₂ gas stream at a temperature rising rate of 20 ° C./min, and the endothermic behavior associated with the melting of the film is analyzed by the first derivative and the second derivative to determine the temperature at which a peak or shoulder is determined, and the film is melted. Set to peak temperature.

(4) Total melting energy ΔHu (J / g) As in the case of (3), 10 mg of film was used as a thermal analysis system SSC / 5200, DSC2 manufactured by Seiko Instruments Inc.
It is set to 20 and heated at a temperature rising rate of 20 ° C./min in a N ₂ gas stream, and it is determined from the area on the melting side on the DSC chart corresponding to the endothermic energy accompanying the melting of the film.
This area is the area on the heat absorption side from the baseline to the endothermic side by increasing the temperature, further increasing the temperature, the melting peak on the highest temperature side, and then returning to the baseline position. The area (a) is obtained by connecting a straight line from the start temperature position to the end temperature position. In (indium) was measured under the same DSC measurement conditions, and this area (b) was 2
Calculated from the following formula as 8.6 J / g.

(A / b) × 28.6 = ΔHu (total) (J /
g)

(5) Glass transition temperature Tg (° C) 10 mg of film was set on a thermal analysis system SSC / 5200, DSC220 manufactured by Seiko Instruments Inc.,
After heating to 300 ° C. at a temperature rising rate of 20 ° C./min in a N ₂ gas stream, melting and holding at a temperature of 300 ° C. for 3 minutes, quenching with liquid nitrogen, and again at a temperature rising rate of 20 ° C./min. Heat and measure glass transition temperature. The glass transition temperature is sensed as the DSC curve bends and the baseline translates due to changes in specific heat. The intersection of the tangent line of the baseline at a temperature below the bending point and the tangent line of the point where the inclination is maximum in the bent portion is set as the bending start point, and this temperature is set as the glass transition temperature Tg.

(6) Film thickness The film thickness t (μm) is defined by the width W (c) of the film.
m), the weight when sampling the length to 1 (cm) is G (g), and the density is d (g / cm ³ ), it is calculated by the following formula.

[0060]

(Equation 1)

(7) Heat shrinkage (heat shrinkage at 150 ° C.) A film sample having a size of 350 mm × 350 mm is marked at a predetermined temperature of 150 ° C. with a mark of 300 mm in the center in the vertical and horizontal directions. Ten samples were suspended in a set tester industry hot air thermostatic chamber without tension, held for 30 minutes, taken out, the distance between gauges was measured again, and the heat shrinkage rate was calculated by the following formula, n The average value of 10 is shown.

[0062]

(Equation 2)

[However, L ₀ : original length (distance between gauge marks 300
mm), L: length after test (unit: mm)]

(8) Tensile Elastic Modulus (Young's Modulus) (kg / mm ² ) The film was cut into a sample width of 10 mm and a length of 15 cm, the chuck space was set to 100 mm, the tensile speed was 10 mm / min, and the chart speed was 100 mm / min. The tensile modulus of elasticity (Young's modulus) is calculated from the tangent line of the rising portion of the load-elongation curve obtained by pulling with a universal tensile tester of the type.

(9) Surface roughness of film (Ra) It is a value defined by JIS-B0601 as the center line average roughness (Ra). In the present invention, the optical stylus non-contact of Kosaka Laboratory Ltd. is used in the present invention. It measures using a three-dimensional roughness meter (ET-30HK). The measurement conditions are as follows. (A) Laser: Semiconductor laser wavelength 780 nm (b) Laser beam diameter: 1.6 μm (c) Cutoff: 0.25 mm (d) Measurement length (Lx): 1 mm Vertical magnification ratio 10,000 times, lateral magnification ratio 200
Double, sampling pitch 2 μm, number of scans 100 (hence Y-direction measurement length Ly = 0.2 mm), the profile of the projection on the film surface is measured, and the roughness curved surface is Z = f (x, y). When expressed by, the value (Ra: μm) given by the following equation is defined as the film surface roughness.

[0066]

(Equation 3)

Further, regarding the projection height, the projection height at the point where the area ratio from the reference level is 70% is set to 0 level, and the difference from the height is defined as the projection height, and the number of projections corresponding thereto is read.

(10) Average air layer thickness R on the film surface
p (μm) The average air layer thickness (Rp) is measured by Microtopograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.). That is, light is made incident on a glass prism which is brought into close contact with the film at a pressure of 1.5 kg / cm ² , and the average air layer thickness in the contact state between the glass prism and the film is determined by the following equation by the change in the amount of reflected light.

[0069]

(Equation 4)

(11) Film-forming property of film Judgment is made based on the number of times film breakage occurred when biaxially stretched film-forming was continuously produced for 8 hours. Although the ultrathin film is likely to break, it is usually difficult to put into practical use unless the value is twice or less than 8 hours. ◯: Breakage rate = 0 times / 8 hours Δ: Breakage rate = 1 to 2 times / 8 hours X: Breakage rate = 3 to 4 times / 8 hours XX: Breakage rate = 5 times or more / 8 hours

(12) Practical characteristics of heat-sensitive stencil printing base paper When substantially the heat-sensitive film itself is used as the heat-sensitive stencil printing base paper (supportless heat-sensitive stencil printing base paper), a heat-fusion preventing layer is provided on both sides of the heat-sensitive film. Acrylic silicone (US-270: manufactured by Toagosei Co., Ltd.) and quaternary ammonium salt dodecyltrimethylammonium chloride as an antistatic agent at a dry weight ratio of 1: 1 of 0.2.
The heat-sensitive stencil printing base paper is prepared by coating with a Meyer bar (metal rod) so as to obtain g / m ^2. (Example 1)
9 to Comparative Examples 1 to 11). When a heat-sensitive film laminated with a porous support is used as a heat-sensitive stencil printing base paper (as is conventional), the heat-sensitive film is mixed with polyester fiber having a basis weight of 8 g / m ² as an ink-permeable porous support. Using a Japanese paper made of vinyl acetate adhesive 1.
Adhesive lamination was performed so that the adhesion amount was 0 g / m ² , and acrylic silicone (US-270: manufactured by Toagosei Kagaku Co., Ltd.) was used as a heat-sealing preventing layer on the heat-sensitive film surface in a dry weight of 0.1.
The heat-sensitive stencil printing base paper is prepared by coating so as to be g / mm ² (Examples 10 to 13, Comparative Examples 12 to 17). The thermal stencil printing base paper prepared as described above is applied with a thermal head by using Ricoh's preport VT-3820 + Ricoh's PC link system (PC online adapter) + Apple's Macintosh (personal computer). The energy is changed as shown below (Table 1), and a gradation image of 24 gradations (solid pattern) is formed by combining a character image (various symbols) and a matrix. In the case of a support-less heat-sensitive stencil sheet, the plate-making base paper is manually set on the copper plate for printing, and in the case of a heat-sensitive stencil sheet with a support, the
Print.

[0072]

[Table 1]

(I) Perforation Sensitivity The image density (ID) of the solid part of the printed matter is measured by using a Macbeth densitometer, and the following judgment is made based on the image density. ⊚: Image density (ID) is 1.0 or more ○: Image density (ID) is 0.9 or more and less than 1.0 Δ: Image density (ID) is 0.7 or more and less than 0.9 ×: Image density (ID) ) Is less than 0.7

(Ii) Print quality The 7-character English letters on the printed matter are observed under a microscope and judged as follows based on the presence or absence of missing characters. ⊚: No character missing (r = 0% when the character missing rate is r) ○: No character missing in 80% or more of the characters (r ≦ 20
%) △: No character missing in 60% or more and less than 80% of characters (20 <r ≦ 40%) ×: No character missing in 50% or more and less than 60% of characters (40 <r ≦ 50%) XX: 50 No character missing in less than% (r> 5)
0%)

(Iii) Plate-making wrinkle Evaluation was made only for the case of a supportless heat-sensitive stencil sheet. It is determined as follows based on the solid portion of the printed matter, the print quality of 5 cm × 5 cm square, and 1 cm × 1 cm square, and the presence or absence of white spots due to wrinkles. ◎: No white spots due to wrinkles even on a solid 5 cm × 5 cm square ○: No white spots due to wrinkles on a solid 1 cm × 1 cm square, but white spots due to wrinkles on a solid 5 cm × 5 cm square △: 1 cm × 1 cm square solid There is a slight white spot due to wrinkles. ×: 1 cm x 1 cm square solid white spot due to wrinkles.

(13) Comprehensive Evaluation The results of the three evaluation items of (11) film forming property of film and (12) practical properties of heat-sensitive stencil printing base paper are judged according to the following criteria. ◎: Perforation sensitivity is ◎ and other items do not have × or XX ○: Perforation sensitivity is ○ and other items do not have × or XX △: Perforation sensitivity is △ and other items are No x or no x x x: Any item has x or x x A comprehensive evaluation of ◎ or O is desirable in terms of both operability and stencil printing paper characteristics.

Examples 1 to 9 and Comparative Examples 1 to 11 The following polyesters were prepared as raw materials for film formation, and blended so that the polyester compositions shown in Table 2 were used. As the polyethylene terephthalate (PET) -based polyester, polyethylene terephthalate (abbreviated as PET) having an [η] of 0.65, and isophthalic acid components in the proportions of 12, 17, and 25 mol% (based on all acid components), respectively, are used. Polyethylene terephthalate / isophthalate copolymer ([PET / IA ¹² , PET / IA ¹⁷ , PET / PET /
IA ²⁵ ), the acid component is terephthalic acid, and the diol component is 30 mol% 1,4-cyclohexanedimethanol (trans / cis = 72/28) and 70 mol% ethylene glycol [η]. Is 0.
75 is a substantially amorphous copolyester (PET /
Abbreviated as CHDM ³⁰ ; manufactured by Eastman Kodak Company
KODAR (registered trademark) PETG6763 equivalent) was prepared. Polyhexamethylene terephthalate (PHT)
As the system polyester, an isophthalic acid component is copolymerized at a ratio of 10 mol% (based on all acid components), and [η] is 1.
A polyhexamethylene terephthalate / isophthalate copolymer of 30 (abbreviated as PHMT / IA ¹⁰ ) was prepared. Examples of the polybutylene terephthalate (PBT) -based polyester are polybutylene terephthalate (abbreviated as PBT) having an [η] of 1.10 and an isophthalic acid component copolymerized at a ratio of 13 mol% (based on all acid components), A polybutylene terephthalate / isophthalate copolymer (abbreviated as PBT / IA ¹³ ) having [η] of 0.95 was prepared.

Spherical silica particles having an average particle size of 1.5 μm were prepared in order to appropriately roughen the surface of the biaxially stretched film when the raw material polyester was blended so as to have the polyester composition shown in Table 2. And spherical silica particles having an average particle size of 0.3 μm are each 0.3% with respect to the total amount of polyester.
3 wt% and 0.15 wt% were added and blended. The raw material thus obtained is sufficiently dried and then fed to an extruder to adjust the temperature suitable for the polyester composition to 225 to 225.
It was melt-extruded by selecting from 280 ° C., and was brought into close contact with a casting drum (rotating cooling drum) having a surface temperature of 15 ° C. by an electrostatic application contacting method to be cooled and solidified to obtain an unstretched film. This unstretched film has a stretching temperature suitable for the polyester composition selected from 45 to 95 ° C. and a lengthwise stretch of 2.8 to
After sequentially biaxially stretching at a magnification of 4.0 times and 3.2 to 3.9 times in the transverse direction, once cooled, heat treated at 50 to 150 ° C., and biaxially stretched to a thickness of 3.5 μm. A polyester film was produced. The thickness thus obtained is 3.5μ
The biaxially stretched polyester film of m was used as a heat-sensitive film, and as shown in the measuring method of the practical characteristics of heat-sensitive stencil printing paper, a heat-sealing preventive layer and an antistatic agent were applied and evaluated as a supportless heat-sensitive stencil printing paper. did. Table 3 shows the results.

[0079]

[Table 2]

[0080]

[Table 3]

Examples 10 to 13 and Comparative Examples 12 to 17 The polyester raw materials used in Examples 1 to 9 and Comparative Examples 1 to 11 were prepared, and the average particle size was also adjusted so that the polyester compositions shown in Table 4 were obtained. Spherical silica particles having a particle size of 1.5 μm and spherical silica particles having an average particle size of 0.3 μm were added and blended so as to be 0.5 wt% and 0.2 wt% with respect to the total amount of polyester. A thickness of 1.5 μm was obtained in the same manner as in Examples 1 to 9 and Comparative Examples 1 to 11 except that the raw material thus obtained was used.
m biaxially oriented polyester film was produced. The composition is shown in Table 4. The thickness thus obtained is 1.5 μm
The biaxially stretched polyester film of No. 1 was used as a heat-sensitive film, and as shown in the measuring method of the practical characteristics of heat-sensitive stencil printing base paper, laminated with Japanese paper mixed with polyester fiber, further coated with a heat-sealing prevention layer, and evaluated as a base paper. . Table 5 shows the results.

[0082]

[Table 4]

[0083]

[Table 5]

[0084]

According to the present invention, it is possible to provide a film for heat-sensitive stencil printing base paper which has more excellent perforation sensitivity and has improved resolution, printing quality and printing durability during printing. Further, it is possible to provide a heat-sensitive stencil printing base paper obtained by laminating the heat-sensitive stencil printing base paper film and a porous thin-film support, and a supportless heat-sensitive stencil printing base paper consisting only of the heat-sensitive stencil printing base paper.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kotaro Kato 3-37-19 Oyama, Sagamihara-shi, Kanagawa Teijin Ltd. Sagamihara Research Center (72) Hiroshi Tomita 3-37-19 Oyama, Sagamihara-shi, Kanagawa No. Teijin Limited Sagamihara Research Center (72) Inventor Hiroshi Tateishi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd.

Claims (8)

[Claims] 1. A biaxially oriented polyester film, wherein the polyester constituting the film is (A) polyethylene terephthalate polyester, (B) polyhexamethylene terephthalate polyester and (C).
Polybutylene terephthalate-based polyester is represented by the following formulas (1) to (3) 35 ≦ a ≦ 65 (1) 15 ≦ b ≦ 45 (2) 0 ≦ c ≦ 45 (3) where , A is the ratio (% by weight) of the component (A), and b is (B).
The ratio of the components (% by weight), c is the ratio (% by weight) of the component (C), and the content of the film is 1
A film for heat-sensitive stencil printing base paper, which has a heat shrinkage ratio at 50 ° C. of 30% or more. 2. Total melting energy of film (ΔHu)
Is 17 to 50 Joules (J) / g, and the film for heat-sensitive stencil printing base paper according to claim 1. 3. Young's modulus of the film is 250 kg / mm
^{2. The} film for heat-sensitive stencil printing base paper according to claim 1, which is ² or more. 4. The center line average roughness (Ra) of the film surface.
Is 0.015 to 0.5 [mu] m, and the average air layer thickness is 2.2 to 5.0 [mu] m. 5. The film for base paper for heat-sensitive stencil printing according to claim 1, wherein the thickness of the film is 0.2 to 10 μm. 6. The film for heat-sensitive stencil printing paper according to claim 1, wherein a layer for preventing heat fusion and / or an antistatic layer is provided on the surface of the film. 7. A heat-sensitive stencil printing base paper obtained by laminating a porous thin-film support to the film according to claim 1 or 6. 8. A heat-sensitive stencil printing base paper which comprises the film according to claim 1 or 6 and does not use a porous thin-film support.