JPH0645269B2 - Film for heat-sensitive stencil printing base paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a film for heat-sensitive stencil printing that is perforated by heat generated by a xenon flash lamp or a thermal head. The principle of this plate making method is, for example, Japanese Patent Publication No. 41-7623, Japanese Patent Publication No. 55-103957, and Japanese Patent Publication No. 59-1436.
It refers to a well-known method described in Japanese Patent Publication No. 79 and the like.

[Prior Art] As a base paper for heat-sensitive stencil printing, a film obtained by laminating a film for heat-sensitive stencil printing base paper and a porous support with an adhesive is usually used. , Vinylidene chloride copolymer film, polypropylene film, and polyethylene terephthalate film have been used, and thin paper and tetron gauze have been used as the porous support.

In addition, as disclosed in Japanese Patent Publication No. 60-1198, there has been proposed a structure in which two kinds of polymers having different melting points or softening temperatures of 2 ° C. or more are arranged in the width direction of the film. It was

[Problems to be Solved by the Invention] However, these have the following drawbacks.

1) When a vinyl chloride or vinylidene chloride copolymer film is used as a film for heat-sensitive stencil printing base paper, letters after printing do not appear clearly.

2) Polypropylene and polyethylene terephthalate films give clear text, but solid printing (●
Symbols or figures such as and ■ that have a large ink adhesion area, are called solid printing. ) Can not get a clear one.

3) In addition, the unevenness in the thickness of characters and the size compatibility in solid printing are partially deteriorated.

4) Sensitivity is poor when printing characters and solid printing.

5) It is not suitable for printing photos, etc., because it does not show shades during solid printing.

6) After perforation, the original document and the film for heat-sensitive stencil printing paper are fused, and therefore cannot be used unless a release agent is coated.

The present invention eliminates the above-mentioned drawbacks, both characters and solid printing are clear, there is no unevenness in the thickness of characters, the size compatibility in solid printing is good, and both characters and solid printing have good sensitivity, An object of the present invention is to provide a film for heat-sensitive stencil printing base paper which can express light and shade and can be released from an original without using a release agent or the like.

[Means for Solving Problems] At least one wax having at least one kind of a wax mainly composed of a compound composed of a higher aliphatic monocarboxylic acid having 10 to 33 carbon atoms or an ester thereof in 100 parts by weight of polyester is used. It is a biaxially stretched film containing 005 to 5 parts by weight, and the film has a crystal melting energy of 3 to 11 cal / g, which is a film for heat-sensitive stencil printing base paper.

The heat-sensitive stencil printing base paper in the present invention is perforated plate-making by receiving heat from a xenon flash lamp, a thermal head or the like as described above, and a heat-sensitive stencil printing base paper film and a porous support were laminated. It is a thing.

The present invention is an improvement of the film (hereinafter simply referred to as a heat-sensitive film) used for the base paper for heat-sensitive stencil printing.

The polyester in the present invention is a polyester having an aromatic dicarboxylic acid as a main acid component and an alkylene glycol as a main glycol component.

Specific examples of the aromatic dicarboxylic acid include teretaric acid, isophthalic acid, naphthalenedicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, anthracenedicarboxylic acid, α , Β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylic acid and the like. Of these, terephthalic acid is particularly desirable.

Specific examples of the alkylene glycol include ethylene glycol, trimethylene guicol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol and the like. Of these, ethylene glycol is particularly desirable.

Of course, these polyesters are preferably copolyesters (copolymerized polyesters), and examples of components to be copolymerized include diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, p-oxyrylene glycol, 1, 4-cyclohexanedimethanol, diol components such as 5-sodium sulforesorcin, adipic acid, sebacic acid, phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 5-
Examples thereof include dicarboxylic acid components such as sodium isophthalic acid, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, and oxycarboxylic acid components such as p-oxyethoxybenzoic acid.

In the above polyester, of course, known additives,
For example, an antistatic agent, a heat stabilizer, an ultraviolet absorber or the like may be added in an amount that does not impair the effects of the present invention.

The heat-sensitive film of the present invention needs to be biaxially stretched, and uniaxially stretched or unstretched film causes unevenness of perforation,
Even after printing, there are missing parts. The degree of biaxial stretching is not particularly limited, but those having a plane orientation coefficient of 0.90 to 0.98 are preferable for the present invention.

Further, the crystal melting energy (ΔHu) (hereinafter simply referred to as ΔHu) of the heat-sensitive film is 3 to 11 cal / g. It is preferably 5 to 10 cal / g. If it is less than 3 cal / g, it will stick to the base paper (original) and it will not be possible to print clear characters. If ΔHu is 5 cal / g or more, clearer character printing is possible. Further, if ΔHu exceeds 11 cal / g, solid printing, sensitivity, and expression of density (hereinafter referred to as sensitivity) are poor, and the object of the present invention cannot be obtained. When ΔHu is 10 cal / g or less, the drilling time can be shortened and the productivity is improved.

Further, the heat-sensitive film of the present invention preferably has a film thickness of 0.2 μm to 5 μm, more preferably 0.3 μm to 4 μm.

If it is less than 0.2 μm, it becomes difficult to bond it to the porous support, and the number of printing sheets to be described later is also reduced. Also,
If it exceeds 5 μm, there is a problem in improving the sensitivity, and missing characters are likely to occur.

The compound whose main component in the present invention is a higher aliphatic monocarboxylic acid having 10 to 33 carbon atoms is, as specific examples, capric acid, lauric acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid. , Melissic acid, nognoceric acid, cerotic acid, montanic acid, hentriacontanoic acid, petroselinic acid, oleic acid, erucic acid, linoleic acid and acid mixtures containing them. Of these, higher aliphatic monocarboxylic acids having preferably 18 to 33 carbon atoms, and more preferably 20 to 32 carbon atoms are preferable in terms of letters, solid printing sensitivity, and shading expression.

The higher aliphatic monocarboxylic acid ester in the present invention means the above-mentioned higher aliphatic monocarboxylic acid having 2 carbon atoms.
It is obtained by partially or entirely esterifying with a monohydric or dihydric alcohol having ˜33. Specific examples include montanic acid ethylene glycol ester, montanic acid ethyl ester, montanic acid ceryl, octanosyl lignocerate, myricyl cerotinate, ceryl cerothate, and the like, naturally obtained montan wax, carnauba wax, beeswax, Candelilla wax, nuka wax, and squid wax are also preferably used.

The main component in the present invention means one containing the compound in an amount of 50% by weight or more.

In the present invention, when the number of carbon atoms of the higher aliphatic monocarboxylic acid is less than 10, the bleed-out to the film surface is severe, the adhesiveness with the porous support is remarkably poor, and when the number of carbon atoms exceeds 33, The sensitivity of solid printing becomes poor and it becomes impossible to express light and shade.

In the present invention, as the ester composed of a higher aliphatic carboxylic acid and an alcohol, the number of carbon atoms of the acid and alcohol of the structure is preferably 18 to 3 both.
The ester obtained by the combination of 3, and more preferably 20 to 32 is desirable in that good solid printing sensitivity can be improved and the expression of shading can be imparted.

In the present invention, the content of at least one compound consisting of a higher aliphatic monocarboxylic acid and its ester (hereinafter referred to as a specific wax) is 0.005 to 5 parts by weight with respect to 100 parts by weight of polyester. It is necessary and is preferably 0.01 to 3 parts by weight. The above content is 0.00
If the amount is less than 5 parts by weight, not only the effect of preventing fusion with the original document is not exhibited, but also solid printing sensitivity is not improved and grayscale expression is not possible. If it exceeds 5 parts by weight, bleeding out to the surface of the film becomes severe, and the adhesiveness to the porous support is lost, and it cannot be used for this purpose.

The heat-sensitive film of the present invention preferably has a heat shrinkage rate of 5 to 50% at 150 ° C. for 15 minutes. It is more preferably 8 to 40%.

If it is less than 5%, the sensitivity is poor for both characters and solid printing. On the other hand, if it exceeds 50%, curling occurs after perforation, resulting in uneven thickness when printing characters.

The sensitivity film of the present invention may have a multi-layered structure (two or more layers), and may satisfy the present requirement value in a laminated structure. Further, the heat-sensitive film of the present invention may be added with an additive having an absorption peak in the wavelength range of flash light irradiation. In order to improve the adhesion to the porous support, the surface of the heat-sensitive film may be subjected to corona discharge treatment in air, carbon dioxide gas and nitrogen gas, or a mixed gas of these.

Further, the heat-sensitive film of the present invention contains the inert particles in an amount of 0.001 to 2 parts by weight, preferably 0.002 to 1 part by weight, based on 100 parts by weight of the polyester.
The slipperiness of the film can be further improved, and the light and shade expression can be further improved.

The inert particles referred to here are the IIA and III of the Periodic Table of the Elements.
Particles selected from oxides or inorganic salts of B, IVA, IVB group elements, such as calcium carbonate obtained as a synthetic or natural product, wet silica (silicon dioxide), dry silica (silicon dioxide), and silica. Examples thereof include aluminum oxide (kaolinite), barium sulfate, calcium phosphate, talc, titanium dioxide, aluminum oxide, aluminum hydroxide, calcium terephthalate and calcium silicate.

In addition, it is preferable that the average particle size of the above-mentioned inert particles is 0.1 to 3 μm, preferably 0.1 to 2 μm, because the film has good slidability and gradation expression.

[Manufacturing Method] Next, a method for manufacturing the heat-sensitive film of the present invention will be described.

The heat-sensitive film of the present invention is obtained by blending a polyester copolymer or a copolymerized product as described above with homopolyethylene terephthalate, etc., and adding a specific wax to this resin is supplied to an Oshiyama machine. , Extrusion, T-die or inflation cast, and then biaxially stretched.

This biaxial stretching is higher than the glass transition temperature (Tg) (hereinafter referred to as Tg) and is in the range of (Tg + 50 ° C.),
Stretching is preferably performed within a range of 2.0 to 7.0 (both in the longitudinal direction and in the width direction).

Further, this film is (melting point -10 ° C) to (melting point -1
The heat-sensitive film of the present invention can be obtained by heat treatment within the range of 20 ° C.

The method of biaxial stretching is not particularly limited, but it can be obtained by using sequential biaxial stretching or simultaneous biaxial stretching (stenter method, tube method, etc.).

A heat-sensitive stencil printing base paper is obtained by laminating the heat-sensitive film thus obtained with a porous support.

[Uses] The thus-obtained film for heat-sensitive stencil printing base paper of the present invention is particularly preferable for use in general heat-sensitive stencil printing as well as for use in perforating and printing with flash light irradiation or a thermal head.

[Characteristic Measuring Method and Effect Evaluation Method] Each characteristic used in the present invention is evaluated by the following methods.

(1) Crystal melting energy [Δu (cal / g)] is PERKIN ELMER
It was determined from the area of the heat-sensitive film when it was melted using a DSC-2 type manufactured by the same company.

This area is the area from the baseline to the endothermic side when the temperature rises, and the area until it returns to the position of the baseline when the temperature is further raised.A straight line connects the melting start temperature position to the end temperature position. The area (a) was determined.
In (indium) is measured under the same DSC measurement conditions,
This area (b) was set to 6.8 cal / g and calculated by the following formula.

a / b × 6.8 = ΔHu (cal / g) (2) Character printing evaluation Character sharpness JIS 1st level character is used as a base paper (original) with a character size of 20 mm and made with Tetoron gauze. The porous support and the heat-sensitive film of the present invention (similarly for Examples and Comparative Examples) are attached to each other, and a "RISO business card pretend" plate-making machine is used by a printer (made by Ideal Science Industry Co., Ltd.). The plate made and printed was evaluated as follows.

The evaluation is made with three levels of A, B, and C by the naked eye, A looks similar to the base paper, and B differs from the base paper and the lines are partially cut or stuck, but cut to an unreadable state. Say.

Character size 5.0 mm using the same plate making and printing machine as in the evaluation item for character thickness unevenness
The characters on the mouth were printed, and the printed state was visually evaluated.

Compared to the characters on the base paper (original), the characters are clearly uneven in thickness, and those that are not readable are indicated by an X, and those that are readable but can be read, even though they have uneven thickness. The circles and those having no thickness irregularity are indicated by the circles.

Character print sensitivity evaluation Pencil hardness 7H, 6H, 5H, 4H, 3H, 2H, H 7
A type was prepared, and a manuscript in which characters were written at a basting pressure of 150 g was used as a manuscript, and this manuscript was used to evaluate whether the characters were legible or not. When written with 7H, the color becomes the lightest and the sensitivity is highest, and as H becomes higher, the black becomes darker and the sensitivity becomes worse.

(3) Evaluation of solid printing Evaluation of sharpness of solid printing ● Using (1-5 mmφ base paper (rounded and filled with black), the same plate as above was printed and printed as follows. evaluated.

The size of the base paper was used as a reference, and the judgment was made by the unevenness (partial) of the contour. Those with irregularities of 200 μm or more larger than the size of the base paper were marked with a cross, indicating poor appearance and unclear, and those with irregularities of 50 μm or less were marked as clear and indicated by a circle. The intermediate one is indicated by a triangle. Depending on the usage pattern, the one marked with a triangle can also be used.

Correspondence with the base paper size of solid printing Print in the same way as in the paragraph, and evaluate the size in all directions (0 and 180 °, 45 ° and 225 °, 90 ° and 270 °, 135 ° and 315 °). , And the correspondence between the size of the base paper and the size was evaluated. Those having a difference of not less than 500 μm from the size of the base paper (sometimes large and some small) have good compatibility and are indicated by ◯. I showed the middle one with a triangle,
It can be used depending on the application.

Evaluation of sensitivity of solid printing and expression of light and shade "Macbeth" reflection densitometer, RD-918 (kollmorgen company, US
The density was measured in A), and the solid print density of the original was compared with the density after plate making and printing.

First, with the above-mentioned densitometer, the concentration is 0.90, 0.50, 0.3.
A solid-printed original having a size of 15 mm was prepared so as to be 5, 0.20. Then, using this original, plate making and printing were performed in the same manner as described above.

The printed matter was measured with the above-mentioned densitometer, and the sensitivity for each density was obtained using the following formula.

Sensitivity for each density = Density after printing for each density / Original density for each density When all the sensitivities for each density are 0.8 or more, the expressivity of sensitivity and light and shade is good, and is indicated by ⊚, 0.7 or more. 0.
A value of less than 8 is considered to have poor expression of sensitivity and shading ×
It is indicated by a mark. When all the sensitivities for each concentration are satisfied, and if any one is bad, it is ranked below that.

(4) Heat Shrinkage The film is sampled in a width of 1 cm and a length of 30 cm, a mark is placed 5 cm from one end of the fill film, and a mark is placed 20 cm therefrom.

A load of 3 g was applied to the tip of this film, and Tabai Co., Ltd.
After processing at 150 ° C. for 15 minutes in a “Perfect Oven” manufactured by the company, the length between marks on the film was measured (length after processing) and calculated from the following formula.

(5) Adhesiveness It means the adhesiveness between the Tetoron gauze used as a porous support and the heat-sensitive film, and a cellophane tape was attached to each surface, which was peeled off and evaluated.

If the Tetron gauze is completely peeled off, the adhesive strength is insufficient ×
Marked with a mark, and if it does not peel at all, the adhesive strength is sufficient ○
It is indicated by a mark. The part that peels off partially is indicated by a triangle.

(6) Releasability It means the peelability between the original after plate making and the heat-sensitive stencil printing base paper, and those that can be peeled without any resistance are considered good.
Although it is stuck to the mark and the original, but it can be peeled off without various defects in the plate making part, the workability is inferior but it can be used as Δ mark, peeling causes defects in the plate making part, and in severe cases Those that caused tears were marked as unusable with a cross.

(7) Number of printed sheets In order to check the durability, the number of sheets was shown until the thermosensitive film was slightly torn by a printing machine and the same characters and solid printability as the first sheet were not obtained.

(8) Curl property The heat-sensitive stencil printing base paper was evaluated as follows in the state where the plate making was completed by the same plate making machine as described above.

Cut the heat-sensitive stencil printing base paper after plate making into 5 x 8 cm size,
This was placed on a flat table with the surface of the heat-sensitive film facing up, and those that did not curl at all were marked as good, those that floated by 10 mm or more were marked as bad, and the intermediate one was marked with Δ.

(9) Plane Orientation Coefficient The refractive index (Nz) in the thickness direction of the film of the present invention and the film of the present invention are kept at a temperature 50 ° C. higher than the melting point for 5 minutes (however, sandwiched between glass plates so that the surface does not become uneven), The sample was taken out, the refractive index (Nzo) in the thickness direction was calculated, and was calculated by the following formula.

Plane orientation coefficient = Nz / Nzo An Atsube refractometer was used to measure the refractive index.

[Examples] The present invention will be described based on Examples.

Examples 1 to 5 and Comparative Examples 1 to 2 As raw materials, eletin terephthalate, isophthalate, and copolymer were used. The ratio of isophthalate was 30 mol%, 22.5 mol% in the order of Comparative Example 1 and Examples 1 to 5,
Copolymers of 20 mol%, 17.5 mol%, 15 mol% and 2.5 mol% were used, and 0.51 part by weight of carnauba wax was added to 100 parts by weight of the copolymerized product. Both were supplied to the extruder with IV = 0.6, melt-extruded from a T die at 280 ° C., and rotated by a cooling roll (temperature 50
℃) and cast, and send this film to a stenter heated with hot air of 80 ° C, stretched by 3.0 times in the width direction, and subsequently heat-treated in a stenter at 150 ° C for 5 seconds to 2.0 μm. To obtain a biaxially stretched film.

In Comparative Example 2, polyethylene terephthalate homopolymer was used as a raw material, and the temperature conditions were the same except that the temperature was increased by 10 ° C., respectively.

The content of carnauba wax in the obtained heat-sensitive film was 0.5 part by weight based on 100 parts by weight of the copolymer.

Examples 6 to 11 and Comparative Examples 3 to 4 As a raw material, ethylene terephthalate, isophthalate, and copolymer 90 containing 20 mol% of isophthalate were used.
1 part by weight of polyethylene terephthalate homopolymer
0 wt% was blended, and this was added as 100 parts by weight so that the content of carnauba wax was as shown in Table 1. Other conditions were the same as in Example 1.

Example 12, Comparative Examples 5 to 6 As the specific wax, as shown in Table 1, a main component having a different number of carbon atoms was used, and the addition amount was 0.2.
1 part by weight was added. Other conditions were the same as in Example 6, and the film thickness was adjusted to 3 μm.

As described above, when the samples of Examples 1 to 12 and Comparative Examples 1 to 6 were laminated with Tetoron gauze, and plate making and printing tests were carried out,
The results shown in Table 1 were obtained.

From this result, and containing a specific amount of a specific wax, and
By using a polyester biaxially stretched film with a specific melting energy, it is possible to obtain a clear and sensitive product without uneven thickness in character printing, and also clear in solid printing, corresponding to size. A heat-sensitive film having good properties and sensitivity was obtained.

Examples 13 to 17 and Comparative Examples 7 to 8 As raw materials, ethylene terephthalate, isophthalate, and copolymer having an isophthalate ratio of 20 mol% were used, and sodium montanate as a specific wax was 1.
01 parts by weight was added. The heat treatment temperature was set to Comparative Example 7 and Example 1.
180 in the order of 3, 14, 15, 16, 17 and Comparative Example 8
℃, 160 ℃, 150 ℃, 140 ℃, 130 ℃, 100
All were the same except that the temperature was 80 ° C and 80 ° C.

When the above sample was subjected to film formation, printing and evaluation in the same manner as in Example 2, the results shown in Table 2 were obtained. The content of sodium montanate at this time was 1.0 part by weight.

What is clear from this result is that when the heat shrinkage ratio is within a specific range, a heat-sensitive film satisfying characters, solid printability and other properties can be obtained.

EFFECTS OF THE INVENTION The present invention provides a film for base paper for heat-sensitive stencil printing excellent as follows by using a biaxially stretched film containing a specific amount of a specific wax in a specific polyester having a specific range of melting energy. I was able to obtain.

(1) With letters and solid printing, clear ones can be obtained.

(2) Characters with uniform thickness can be obtained with good size compatibility in solid printing.

(3) Sensitivity for characters and solid printing is significantly improved.

(4) It is possible to express light and shade at the time of solid printing, and it is possible to obtain not only printing of characters but also printing of photographs and the like.

(5) After perforation, there is no need to coat the release agent, etc., unlike the conventional products, because the original and heat-sensitive film do not fuse.
The cost can be reduced and the work process can be simplified.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-48398 (JP, A) JP-A-60-85996 (JP, A) JP-A-60-97891 (JP, A) JP-A-62-1 149496 (JP, A) JP48-1009 (JP, B1) JP48-1532 (JP, B1)

Claims (1)

[Claims] 1. A polyester containing 100 parts by weight of which has 1 carbon atom.
A biaxially stretched film comprising at least one kind of wax containing 0.005 to 5 parts by weight as a main constituent of a compound consisting of 0 to 33 higher aliphatic monocarboxylic acid or its ester. A film for base paper for heat-sensitive stencil printing, which has a crystal melting energy of 3 to 11 cal / g.