JPH0462095A - Tissue paper for thermal stencil printing - Google Patents

Abstract

PURPOSE:To obtain a high-strength Japanese paper with low friction charging voltage and an ability to eliminate generation of static electricity by providing a tissue paper of elongatable vinylon fiber within a specific range with a specific amount of at least, either one of urethane or epoxy resin contained in the interwoven part and the front of fiber. CONSTITUTION:The amount equal to 10wt.% of fiber is of 2-denier filament elongatable vinylon filament with a fiber length of 15mm or less and a dissolving temperature of 100 deg.C or higher. This fiber is used for tissue paper with a basis weight of 5 to 15g/m<2> and a thickness of 10 to 50mum. At least, either one of urethane or epoxy resin is applied to the interwoven part and front of fiber at a rate of 3g of resin per 1m<2> of tissue paper. The fiber other than vinylon fiber which constitutes the tissue paper is normally used natural fiber and/or regenerated fiber. The preferable regenerated fiber should have the size of 2 denier in terms of filament and the fiber length of 15mm or less. If these requirements are satisfied, the fiber becomes highly dispersive and ideally entangled to bind together tightly. When processing the tissue paper using resin, it is preferable that the paper receive the application of a urethane or epoxy resin solution or be impregnated with its emulsion or receive the application of the solution using a gravure roll. After that, the sheet is dried using a hot blast drier or a heating roll.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to heat-sensitive stencil paper, and in particular to thermal perforation paper that is thermally perforated with a flash of light from a xenon flash lamp or a heat-sensitive element such as a thermal head and used for stencil printing. The present invention relates to thin paper used as a porous support for heat-sensitive stencil paper.

[Conventional technology]

Heat-sensitive stencil paper is made by laminating a thermoplastic resin film and a porous support.Recently, improvements have been made to this heat-sensitive stencil paper in order to improve the quality of stencil printing, namely the material and thickness of the thermoplastic resin film. Improvements have been made to make the film thinner or to improve the porous support.

The porous support is used to support the thermoplastic resin film, and is used to ensure direct imageability of the heat-sensitive stencil paper and to improve printing durability. As the material, thin paper, gauze (screen), non-woven fabric, etc. are used. High-resolution prints can be obtained by using gauze, but the gauze itself is expensive, and non-woven fabrics have thick fibers, so only low-quality prints can be obtained, so thin paper is generally used. is used. Examples of porous thin paper include: ■ So-called washi paper made from natural fibers such as kozo, mitsumata, and Manila hemp (Jibun [Publication No. 41-7623); ■ Paper made from recycled fibers and synthetic fibers such as rayon, vinylon, polyester, and nylon. The paper made in
■Mixed paper made by mixing the natural fibers (■) above with the recycled fibers and synthetic fibers (■) (Japanese Patent Publication No. 18729/1983)
, (2) So-called polyester paper (Japanese Patent Publication No. 1988-8809), which is produced by hot-pressing a thin paper made by mixing polyester fibers and fibrous binder fibers with a hot roll, is generally known.

Further, such thin paper has the problem of deterioration in function due to deformation or dimensional change due to humidity or temperature. Therefore, in the past, proposals have been made to reduce the dimensional change when wetted (Japanese Patent Application Laid-Open No. 61-254396), and to impregnate the paper with a synthetic resin liquid, which also functions as an adhesive between tissue paper and thermoplastic resin film. (Japanese Unexamined Patent Publication No. 5547997), and furthermore, a proposal to process a specific resin into a mixed paper made by mixing the natural fibers (■) above and the polyester fibers (■) -2
71293), etc. In addition, regarding polyester paper, we proposed a manufacturing method for making it superior in dimensional stability and heat resistance (Japanese Patent Application Laid-Open No.
No. 76597, Japanese Unexamined Patent Publication No. 76598/1983), etc.

However, the performance required for thin paper used as thermal stencil paper is (I) good ink permeability, clear images and excellent resolution, (It) excellent printing durability, (I) [) Excellent paper strength and no fiber shedding; (IV) The ability to faithfully make and print manuscripts with less deformation and wrinkles due to heat shrinkage; (V) No increase in frictional electrostatic voltage ( In other words, the charged voltage increases,
As a result, handling of the thermal stencil paper deteriorates, and when used in a fully automatic printing machine, curling occurs during the conveyance of the thermal stencil paper, resulting in poor printing. do not have.

[Problem to be solved by the invention]

Tissue paper according to the prior art has the following drawbacks.

In other words, thin paper using natural fibers described in (2) above, although a dispersion side and a sticky agent are added at the time of paper making, can be difficult to pass through due to binding caused by agglomeration of fibers, resulting in defects or missing parts in the image. First, although a paper strength enhancer is generally added during paper making, the strength of the paper is not sufficient, causing wrinkles in the base paper and poor printing durability. In addition, in the case of recycled fibers, synthetic fibers, or mixed papers of synthetic fibers and natural fibers mentioned in ■ and ■ above, although there is improvement in the uniform dispersion of the fibers, the fixation of the fiber intersections is insufficient. Since the paper strength is insufficient, the paper may become deformed or the fibers may come off during lamination or printing, impairing image quality, and printing durability is also poor.

JP-A-61-254 designed to improve dimensional stability when wet
In the case of Publication No. 396 as well, attempts have been made to improve this by blending polyester fibers or rayon cloth or adding a wet paper strength agent such as epoxidized polyamide polyamine resin during papermaking, but the fixation of the intersections of fibers is not sufficient. Printing durability and image quality are poor. Furthermore, in the case of thin paper using polyester paper mentioned in (1) above, although the manufacturing method has been devised to firmly bind the polyester fibers together, the portions where the fibers intersect are not bound by the binder fibers. There are quite a lot of them, and it cannot be said that they are sufficient.

In addition, when a thermal head is used to make a base paper, there is a large thermal contraction due to heat, which causes deformation and wrinkles, making it difficult to print faithfully to the original. Furthermore, there is a problem in that the adhesion between the heat-sensitive film and the thin paper is poor during lamination, resulting in partial peeling from the film, which ultimately reduces image quality and print durability.

In addition, the processing using synthetic resin in the above-mentioned Japanese Patent Publication No. 55-47997 uses a resin with a relatively low softening point and has the function of an adhesive between tissue paper and thermoplastic resin film, so that the intersection portions of fibers are It cannot be said that it is bound with a strong heat-resistant resin, and the resin is softened and insufficiently reinforced, making it unsatisfactory in both paper strength and printing durability.

Furthermore, paper made by mixing the natural fibers described in (1) and the polyester fibers described in (2) of the above-mentioned Japanese Patent Application Laid-Open No. 1-271293 in combination with a specific resin clings to conveying rubber rolls etc. due to static electricity. There may be some problems with handling.

[Means to solve the problem]

As a result of extensive research in order to improve the above-mentioned drawbacks of thin paper used for conventional stencil paper, the present inventor added a specific strong resin to thin paper containing a specific amount of stretched vinylon fibers after papermaking. It has been found that by doing this, the intertwined portions of fibers can be firmly and almost uniformly fixed without reducing the passage of ink. In other words, by combining vinylon fiber and the specific resin, a thin paper with high paper strength, good image quality, and low frictional charging voltage was discovered, and the various requirements required for a thin paper for thermal stencil paper were simultaneously met. A satisfactory invention has been achieved.

That is, in the present invention, 10% by weight or more of the fibers has a single yarn fineness of 2 deniers or less, a fiber length of 15 deniers or less, and a melting temperature of 10 denier or less.
Basis weight 5 to 15 g/made of stretched vinylon fiber at 0°C or higher
m2, thin paper with a thickness of 10 to 50μ■ is coated with at least one type of urethane resin or epoxy resin in the intertwined portions of fibers and on the surface (meaning that 3g of resin is applied per sheet of thin paper) or less This is a thin paper for heat-sensitive stencil paper, characterized in that it has an amount of .

The vinylon fiber used in the present invention has a melting temperature of 10
The temperature is 0°C or higher. If the melting temperature is less than 100''C, the heat resistance of some of the fibers will be poor and the fiber shape will be deformed, resulting in poor image quality.

In the present invention, it is necessary that the drawn vinylon fiber has a single yarn fineness of 2 deniers or less and a fiber length of 15+w+ or less. When the single yarn fineness exceeds 2 denier, uniform passage of ink cannot be obtained. Preferably it is 0.2 to 1 denier.

Furthermore, if the fiber length exceeds 15 mm, the fibers will not be dispersed and the image quality will deteriorate. Preferably it is 3-8 kaku. Furthermore, vinylon fibers must be contained in the thin paper in an amount of 10% by weight or more.

If the vinylon fiber content is less than 10% by weight, uniform fiber dispersibility and good quality formation with little fiber binding cannot be obtained, resulting in poor image quality. Preferably it is 20 to 50% by weight.

In the present invention, the fibers other than vinylon fibers constituting the thin paper are commonly used natural fibers and/or recycled fibers. Preferably, recycled fibers such as Manila hemp, flax, etc., natural broken skin fibers, viscose process rayon fibers, copper ammonia process rayon fibers, etc. are used. It is preferable in terms of dispersibility and binding by entanglement.

In the present invention, the paper-made thin paper has a basis weight of 5 to 15 g.
/m2 and a thickness of 10 to 50 μm. If the basis weight is less than 5 g/nf or the thickness is less than 10 μm, printing durability will be extremely low, which is undesirable. If the basis weight is 15 g/rrf or more and the thickness is 50 μm or more, the passage of ink will be significantly impaired and image quality will deteriorate. Preferably, the basis weight is 8 to 13.5 g/po, the thickness is 25 to 40 μ-
and the density (basis weight + thickness) is 0.25 to 0.40
g/cd, and within this range, the image quality is clear and excellent.

It goes without saying that in the production of thin paper according to the present invention, commonly used dispersants, sticky agents, antifoaming agents, release agents, paper strength enhancers, sizing agents, antistatic agents, etc. may be added. .

In the present invention, the thin paper contains at least one of urethane resin and epoxy resin in the intertwined portions of fibers and on the surface at 3 g/
It is necessary to contain less than rrf. When the amount of resin exceeds 3 g/%, a large number of resin films are formed at the openings of the thin paper, significantly impairing the passage of ink and deteriorating image quality. Preferably 0
．． 5 to 1.58/m2.

Urethane resins and epoxy resins used in the present invention include solvent solution type, water soluble, water dispersion type (emulsion type), and the like.

In addition, non-reactive types and reactive types (1-liquid type, 2-liquid type,
However, in the case of a two-liquid type, the reaction may be carried out by combining a crosslinking agent, a crosslinking accelerator, etc.).

For resin processing of thin paper, it is preferable to impregnate the thin paper with a solution or emulsion of urethane or epoxy resin or apply it with a gravure roll, and then dry it with a hot air dryer or a hot roll.

A suitable drying temperature is 50 to 210°C. Furthermore, the paper strength can be further improved by applying heat-pressing processing using a hot roll at the same time as drying.

In resin processing, it is necessary to pay particular attention to the resin concentration. Although it varies somewhat depending on the basis weight of the thin paper and the type of resin, a solution with a concentration of 7 to 30% is preferable.

In resin processing, paper strength enhancers, sizing agents, etc. that are generally used in paper making may be used in combination.

In the present invention, the mechanism by which the frictional charging voltage can be lowered is presumed to be as follows.

(1) The official moisture content of vinylon is 5.0%, which is higher than other synthetic fibers, and the moisture content does not decrease much even when mixed with natural fibers.

(2) Since vinylon fiber has a hydrophilic group OH, it is difficult to dissociate water and is less likely to be charged compared to other synthetic fibers.

(3) During resin processing, the area where the fibers are covered by the resin is small because the resin gathers at the intersections of the fibers of the thin paper due to capillary action.

From these facts, it is presumed that the electrostatic voltage can be reduced by maintaining the inherent moisture content of the fiber itself.

〔Example〕

The present invention will be explained below using examples. In addition, % is weight %.

Furthermore, each characteristic was evaluated by the following method.

(11 Evaluation of image quality JIS first level characters and designs with character size 5 fine to 2
The same figure with a 0m+ opening and a circle with a diameter of 1 to 10m filled in black was used as a manuscript. In addition, as a heat-sensitive film (stretched thermoplastic synthetic resin film), 2 μI
The polyester film of the present invention and the thin paper as the porous support of the present invention (the same method was used in both Examples and Comparative Examples) were applied using a dry laminator adhesive "Vylon 30" (Toyobo Co., Ltd.).
A heat-sensitive stencil paper (hereinafter referred to as a master) was prepared by laminating the sheets together using a dry laminator using a heat-sensitive stencil paper (hereinafter referred to as a master).

Using this master and manuscript, a digital fully automatic stencil printing machine (Risograph 007DPN manufactured by Riso Kagaku Kogyo Co., Ltd.)
), and the printed material was evaluated as follows.

Evaluation is done with the naked eye in three stages: ○, Δ, and ×. ○ means that the text is as clear as the original, with no uneven text thickness or white spots in solid black areas, and × means that the lines are different from the original. This refers to items that are partially cut off or have uneven font thickness, making them difficult to read and unusable.

Items that are legible and usable even if the line in the middle is partially cut or the thickness of the letters are uneven are marked with a △.

(2) Printing Durability A three-level evaluation of O1Δ and × was performed based on the number of durable sheets printed. That is, the printing machine described in (1) above removes tears, wrinkles, and
Check the number of sheets until streaks occur or the same characters, lines, and black solid areas as on the first sheet cannot be printed.
,000 sheets or more, ◯, 1,500 to less than 3,000 sheets, Δ, and less than 1,500 sheets, ×.

(3) Paper strength The tensile breaking strength (JIS P-8113 and JIS P-8135) of thin paper was evaluated in the papermaking direction (longitudinal) under dry conditions and wet conditions. Dry conditions are
The test piece was kept at a constant temperature (22°C) (relative humidity 66%) for 24 hours.
The test piece was allowed to stand still for a period of time, and the wet condition was such that after being allowed to stand still under the same conditions, the test piece was immersed in water at 15° C. for 20 minutes. Unit: kg/15m Width (4) Thickness Measured according to JIS P-8118.

(5) Air permeability Measured according to JIS P-8117. However, 96% of tissue paper
Measurements were made by stacking the sheets. Unit: seconds/300cc (6) Stiffness A test piece of thin paper with a length of 50 m in the paper making direction (vertical) and a radius of 15
m, one end of the test piece was held horizontally, and evaluation was made based on the angle between the line connecting the free end and the fixed end and the horizontal line. Unit twice.

(7) Frictional charging voltage Measured by JTS L-1094.

Fl! Rubbing cloth: Cotton attached white cloth specified in JIS L-0803 Measurement conditions: 20° C. x 40% humidity Three-level evaluation of O1Δ and × was performed based on the charging potential. The strength of electric shock in the static electricity safety guidelines was used as a reference.

In other words, 1,500V or less is 0.1,500 to 2,5
Less than 00V was Δ, and 2.500V or more was x.

Examples 1 to 6 (^): Manila hemp was digested with alkaline, washed with water, diluted with water to a concentration of 3%, and heated with a beater to a freeness of 18°SR (JI
The beaten S P-8121) and the vinylon fibers shown in Table 1 were uniformly mixed at the blending percentage shown in "°Tissue composition" in Table 3, and epoxidized polyamide polyamino resin was added to this. Mix uniformly as an aqueous solution with a concentration of 2% based on the fibers, use this as paper stock, and use the wet papermaking method in a cylinder paper machine to process the paper as shown in Table 3 "Basic characteristics of thin paper".
Tissue paper having the basis weight, thickness, and density shown in 1 was made.

(B): The individual thin paper rolls obtained in (A) above were coated or impregnated with the resins shown in Table 2. The amount of resin deposited after processing is shown in the column of resin amount in Table 3.

(C): Table 3 shows the characteristics of the processed tissue paper obtained in (B) above and the evaluation results of the master obtained by laminating it with a film.

Example 7 60% Manila hemp used in Examples 1 to 6, 30% vinylon fiber (indication group: Vinylon A) in Table 1, and viscose process rayon fiber [indication group: Sufu (single yarn fineness 0.7 denier, A thin paper take-up roll having the characteristics shown in Table 3 was obtained in the same manner as in Section (A) of Examples 1 to 6. The resin processing and characteristic evaluation of this product were performed in Examples 1 to 6 (B).
The same procedure as in section (C) was carried out. The results are shown in Table 3.

Comparative Example 1 The thin paper made of 100% Manila hemp used in Examples 1 to 6 was produced in the same manner as in Section (A) of Examples 1 to 6, and its characteristics were evaluated. The results are shown in Table 4.

Comparative Example 2 The 100% Manila hemp tissue paper used in Examples 1 to 6 was
It was produced in the same manner as in Section (A) of Examples 1 to 6, and was further subjected to resin processing in the same manner as in Sections (B) and (C) of Examples 1 to 6, and the characteristics of the processed thin paper were evaluated. . The results are shown in Table 4.

Comparative Example 3 Characteristics of the thin paper itself produced in the same manner as Examples 1 to 6 were evaluated. The results are shown in Table 4. Comparative example 4~
6 Thin paper produced in the same manner as in Examples 1 to 6 was further subjected to resin processing in the same manner as in sections (B) and (C) of Examples 1 to 6, and the properties of the processed thin paper were evaluated.

The results are shown in Table 4.

Comparative Examples 7-9 Manila hemp used in Examples 1-6 and each vinylon were uniformly mixed in the specified ratio, and then (A) of Examples 1-6 was mixed.
Thin paper was produced in the same manner as in Section 1, and was further processed with resin in the same manner as in Sections (B) and (C) of Examples 1 to 6, and the characteristics of the processed thin paper were evaluated.

The results are shown in Table 4.

Comparative Example 10 70% of Manila hemp used in Examples 1 to 6 and 30% of polyester fiber [display group: PET (single yarn fineness 0.5 denier fiber length 511 m)) were uniformly mixed, and then Examples 1 to
A take-up roll of thin paper having the characteristics shown in Table 4 was obtained in the same manner as in Section 6 (A).

Both resin processing and characteristic evaluation of this product were carried out in Example 1.
It was carried out in the same manner as in sections (B) and (C) of ~6. The results are shown in Table 4.

Comparative Example 11 Thin paper produced in the same manner as in Examples 1 to 6 was impregnated with SBR resin (NIRAKUSTAR 3307B manufactured by Dainippon Ink). The amount of resin attached is shown in the column of resin amount in Table 4.

Table 4 shows the properties of the thin paper obtained and the evaluation results of the master obtained by laminating it with the film.

(The following is a blank space) [Effects of the Invention] The present invention is a thin paper of heat-sensitive stencil paper obtained by combining a specific range of vinylon fibers and a specific resin within a limited range, and has the following excellent effects. Obtainable.

That is, (1) Japanese paper, which generates less static electricity, can be used as a porous support instead of Japanese paper because of its low frictional charging voltage.

(2) Resin processing produces high-strength Japanese paper with excellent printing durability.

(3) Fibers are uniformly dispersed and have good texture.

(4) Direct images during printing are clear and of high quality.

In this way, it can have excellent performance as a porous support.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. 10% by weight or more of the fibers are drawn vinylon fibers with a single filament fineness of 2 denier or less, a fiber length of 15 mm or less, and a melting temperature of 100°C or higher, basis weight of 5 to 15 g/m^2, thickness of 10 to 50 μm A thin paper for heat-sensitive stencil paper, characterized in that the thin paper contains at least one of urethane resin and epoxy resin in an amount of 3 g/m^2 or less in the intertwined portions of fibers and on the surface.