JP2008188070A - Printed hygienic tissue paper and method for making the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed hygienic tissue paper which is remarkable and well-looking, has design with large patterns and appearing power to consumers, and keeps wrinkles and twisting undevelopable or hardly developable. <P>SOLUTION: Patterns 12 are printed in an aqueous ink under a condition that the number of lines is 40 to 100, a net dot area ratio is 15 to 50%, a pattern occupying ratio where the patterns occupies per 114 mm width is 10 to 30%, and the hygienic tissue paper has at least one pattern with a pattern area of 102 mm<SP>2</SP>to 918 mm<SP>2</SP>, in a hygienic tissue paper surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printed sanitary thin paper that is dot-printed on the surface of tissue paper or toilet paper, and a method for producing the same.

As this type of sanitary thin paper, for example, in the paper making stage, there is one that has been colored in a strip shape or a wave shape by a spray nozzle (see, for example, Patent Document 1).
This sanitary tissue paper is said to be clean and easy to coordinate with fragrances. However, this sanitary thin paper is not good in design because the raw pulp is colored in strips, undulations, etc. along the width in the paper making stage, and it gives the user a sense of incongruity and looks good. There are difficulties.
In addition, when printing a pattern on sanitary thin paper, particularly a toilet paper roll, application of ink using a printing plate (solid printing) causes the paper to shrink and cause twists and wrinkles. For this reason, if the design to be printed becomes large, the amount of ink applied per unit area of the sheet will increase, causing paper wrinkles and creases, pattern collapse, winding failure, and associated processing speed reduction. Has various adverse effects. For this reason, the maximum symbol occupancy ratio of symbols per unit area is about 6% at the maximum, and the current situation is that a large symbol area ratio, that is, a large symbol cannot be printed.
JP 2003-310476 A

  The main problem to be solved by the present invention is a sanitary thin paper that is outstanding and attractive, has a design that appeals to consumers with a large design, and has little or no occurrence of paper wrinkles and creases Is to provide. Other issues will become apparent from the description below.

The present invention that has solved this problem is as follows.
[Invention of Claim 1]
The sanitary thin paper surface, the number of lines 40 to 100, the halftone dot area ratio from 15 to 50% symbol occupancy occupied by symbols per 114mm width is and the symbol area is 10~30% 102mm ² ~918mm ² of at least one Printed sanitary thin paper characterized in that a predetermined pattern is printed with water-based ink under the condition having two patterns.

(Function and effect)
The present inventors have made flexo printing in order to obtain a variety of designs and complicated designs by printing. However, it has been found that the application of ink in halftone printing using a printing plate involves paper dust on the paper and causes clogging and pattern collapse of the printing plate. It has been found that the entrainment of paper dust has various adverse effects on the operation such as not only the crushing of the pattern but also the winding failure of the printed sheet and the accompanying decrease in processing speed.
However, according to the above-mentioned conditions of the present invention, it is possible to prevent the pattern from being crushed due to the entrainment of paper dust, and it is possible to print a design and design that is sufficiently clear for practical use. Further, there is no or little generation of paper wrinkles and creases.

[Invention of Claim 2]
The sanitary thin paper surface, the number of lines 40 to 100, the halftone dot area ratio from 15 to 50% symbol occupancy occupied by symbols per 114mm width is and the symbol area is 10~30% 102mm ² ~918mm ² of at least one A method for producing a sanitary thin paper for printing, characterized in that a predetermined pattern is printed with water-based ink under a condition having two patterns.

(Function and effect)
There exists an effect similar to the thing of Claim 1.

[Invention of Claim 3]
The target sanitary thin paper has a basis weight of 10-30 g / m ² , an elongation of 15-35%, the water-based ink has a viscosity of 10-50 cps, a vehicle of 5-25% by mass, and a water content of 95-75% by mass. The manufacturing method of the printing sanitary thin paper of Claim 2 which prints on the conditions which are these.

(Function and effect)
In such a condition, it is possible to surely perform printing that is clear and does not involve paper dust, although a sheet having a low rice floor and a high elongation rate is targeted.

  According to the present invention, if necessary, a sanitary thin paper having a distinctive and good-looking design with a large design and appealing to consumers, and with little or no occurrence of paper wrinkles and folds is obtained. be able to. Furthermore, the pattern is not crushed due to the entrainment of paper dust.

Next, an embodiment of the present invention will be described.
[Use]
The use of the sanitary thin paper of the present invention is not particularly limited. For example, it can be used as toilet paper, tissue paper, kitchen paper, towel paper, and the like. In particular, it provides a significant advantage in toilet paper roll products with relatively high generation of paper dust. Furthermore, the product width, which appears as a major problem in preventing paper wrinkles and creases, is a significant advantage for sanitary thin paper (sheets) with a thickness of 80 mm to 300 mm.

〔Base paper〕
The sanitary thin paper of this embodiment is produced by applying processing such as printing to the base paper.
In this embodiment, the raw material of the base paper is not particularly limited. Pulp fiber can be selected according to each use such as toilet paper, tissue paper, kitchen paper, towel paper and the like.
Specifically, for example, as pulp fiber (raw pulp) as a raw material, wood pulp, non-wood pulp, synthetic pulp, waste paper pulp, etc., more specifically, groundwood pulp (GP), stone ground pulp (SGP) ), Refiner ground pulp (RGP), pressurized groundwood pulp (PGW), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), bleached chemithermomechanical pulp (BCTMP), etc., mechanical pulp (MP), chemical Craft pulp (KP), soda pulp (AP), sulfite pulp (SP) such as mechanical mechanical pulp (CGP), semi-chemical pulp (SCP), hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP) , Chemical pulp (CP) such as dissolving pulp (DP), nylon, rayo Synthetic pulp made from polyester, polyvinyl alcohol (PVA), deinked pulp (DIP), waste paper pulp such as waist pulp (WP), ground pulp (TP), cotton, flax, hemp, jute, manila hemp, ramie It is possible to use one or several kinds as appropriate from rag pulp, straw pulp, esparto pulp, bagasse pulp, bamboo pulp, kenaf pulp and other auxiliary pulps such as bast pulp, etc. it can.
The pulp fiber raw material is, for example, a known papermaking process (stage), specifically, a base paper that is subjected to processing such as printing through a wire part, a press part, a dryer part, a size press, a calender part, etc. It can be. In making this paper, for example, a suitable chemical such as a pH adjuster such as a dispersant, caustic soda, or aqueous ammonia, an antifoaming agent, a preservative, a release agent, a water-resistant agent, a flow modifier, and a yield improver is added. be able to.

[Hygienic thin paper]
As shown in FIG. 1, the sanitary thin paper 10 of the present embodiment has a pattern portion 12 in which a pattern such as a flower or a tree is drawn which is colored green or pink. If necessary, as shown in the figure, a peripheral coloring portion 11 of a color other than white may be formed around the pattern portion 12. However, the peripheral coloring portion 11 is colored at the paper making stage using a dye that does not cause the paper to be wrinkled or distorted, and is different from the printing and the pattern portion 12 of the present invention.
Moreover, it does not specifically limit as a symbol of the symbol part 12. FIG. For example, plants such as flowers, trees, grass, creatures such as people, animals, fish, shellfish, insects, nature such as mountains, rivers, seas, clouds, forests, forests, planets and satellites such as the moon, sun, stars, etc. Examples are illustrated in which one type or several types are appropriately selected and drawn from patterns such as cars, airplanes, and artificial objects such as trains.
The sanitary thin paper 10 of the present embodiment is obtained by halftone dot printing in which a large number of halftone dots (dots) d, d... Has been made.
In this embodiment, the shape of each halftone dot d, d... Is not particularly limited. For example, in addition to the rhombus as shown in the drawing, it may be a square, rectangle, circle, ellipse, polygon, star or the like (preferably a circle, rhombus or square).
In this embodiment, the physical properties of the base paper are such that when toilet paper or tissue paper is used, the longitudinal strength (MDT) of one ply is 75 to 250 gf / 15 mm, the lateral strength (CDT) is 20 to 100 gf / 15 mm, The elongation (MDS) is preferably 10 to 30% (measurement conforms to JIS P 8113).
On the other hand, when kitchen paper, towel paper or napkin is used, the longitudinal strength (MDT) of one ply is 200 to 1200 gf / 15 mm, the lateral strength (CDT) is 50 to 400 gf / 15 mm, and the longitudinal elongation (MDS). Is preferably 5 to 30% (measurement conforms to JIS P8113).
Furthermore, in the case of toilet paper, the dry longitudinal strength (MDT) of 1 ply according to JIS P 8113) is 45 to 150 gf / 15 mm, the dry transverse strength (CDT) is 15 to 60 gf / 15 mm, and the longitudinal elongation ( MDS) is preferably 10-30%.
If the strength of the base paper is below these lower limit values, breakage or the like may occur during processing such as printing. On the other hand, if the strength of the base paper exceeds these upper limit values, the texture deteriorates. Further, if the elongation of the base paper is below these lower limit values, there is a possibility that breakage or the like may occur during processing such as printing. On the other hand, if the elongation of the base paper exceeds these upper limit values, wrinkles or the like may occur and fine printing may not be performed.
In this embodiment, creping the base paper increases the flexibility of the paper. In that case, the crepe height difference is preferably less than 100 μm, more preferably 10 to 70 μm, and particularly preferably 15 to 40 μm. Since the base paper having a crepe height difference of less than 100 μm has good surface properties, the printing becomes fine and the sanitary thin paper 10 looks good.
The base paper preferably has a crepe rate of 10 to 30%, more preferably 13 to 23%, and particularly preferably 15 to 19%. Since the base paper having a crepe rate of less than 30% has good surface properties, the printing becomes fine and the sanitary thin paper 10 looks good. On the other hand, a base paper having a crepe rate of 10% or more has a soft paper quality with a reduced paper stiffness, so that the sanitary thin paper 10 is comfortable and comfortable to use.
In this embodiment, the sanitary thin paper 10 is preferably 2 plies or 3 plies when toilet paper or tissue paper is used, and the basis weight according to JIS P 8124 of 1 ply is 10 to 25 g / m ² . Preferably there is. When the basis weight is less than 10 g / m ² , it is preferable in terms of softness, but an appropriate strength cannot be ensured. On the other hand, when the basis weight exceeds 25 g / m ² , it becomes too hard and the touch is deteriorated.

[Manufacturing method of sanitary thin paper]
In manufacturing the sanitary thin paper 10 of this embodiment, it is desirable to print on the base paper by flexographic printing (letter printing) using a printing plate roll and a transfer method. Also, intaglio printing such as gravure printing, lithographic printing such as offset printing, and the like can be employed.
In the present invention, it is important to select the number of halftone dots and the dot area ratio of the transfer roll (anilox roll). “Number of lines” means the number of halftone dots per inch (2.54 cm). To do. The “halftone dot area ratio” is the area ratio of halftone dots per unit area.
In the present invention, a predetermined pattern is printed under the conditions that the number of lines is 40 to 100 (more preferably 50 to 80) and the dot area ratio is 15 to 50% (more preferably 20 to 45). If the number of lines is large, it is close to solid printing, and paper dust is involved during printing, resulting in pattern collapse. When the number of lines is small, the height of the convex part increases, and paper dust is mixed between the convex parts, resulting in pattern collapse. On the other hand, when the dot area ratio is high, it is close to solid printing, and paper dust is involved during printing, resulting in pattern collapse. When the halftone dot area ratio is excessively low, the height of the convex portion increases, and paper dust is mixed between the convex portions, resulting in pattern collapse.
The target sanitary thin paper has a basis weight of 10-30 g / m ² , an elongation of 15-30%, a printing ink viscosity of 10-50 cps, a vehicle of 5-25% by mass, and a moisture content of 95-75% by mass. It is desirable to print under the following conditions.
Now, in the present invention, the condition pattern occupancy occupied by symbols per 114mm width is and the symbol area from 10 to 30 percent with at least one symbol of 102mm ² ~918mm ^2, predetermined symbol unit by the water-based ink 12 Is printed.
Here, the “design area” of the present invention refers to the area surrounding the outline of the design. However, the design portion 12 of the illustrated petal has a small gap between one petal and the next petal, so it will be exactly one petal as a design, but in terms of design as one flower In addition, since the distance between the small symbols (petals) is small, that is, it is not a gap where a circle with a diameter of 4 mm, which is an element that avoids the generation of wrinkles and creases, it is not a gap of small symbols unless this condition is satisfied. Is treated as a single symbol. In addition, for example, when there is a set of symbols but there is a gap where a circle with a diameter of 4 mm can enter, the area of the gap is subtracted from the area of one symbol, or a small circle is cut out in a large circle. In the cutout figure appearing in (3), the area of the small circle symbol is subtracted from the area of the large circle symbol to obtain the “design area” of the present invention.
In the present invention, as shown in FIG. 1, a pattern portion 12 having a large symbol area can be printed. The “symbol occupancy rate” of the present invention is the ratio (percentage) of the width S of the “symbol area” occupied by the symbol per 114 mm width (S / W%). In addition, in the example of FIG. 1, W is 114 mm of a toilet paper roll width. Conventionally, as described above, a maximum of about 6% was the limit, but according to the present invention, a symbol can be formed within a range of 10 to 30% as a symbol occupancy rate. In addition, it is possible to print a design with a large design that appeals to consumers. Incidentally, “114 mm width” is the toilet paper roll width defined by JIS. However, it is not limited to the width of 114 mm, and may be shorter or wider than this, and it is found that the definition of “design occupation ratio” of the present invention can be applied as it is within the range of 90 to 130 mm width. is doing. The “symbol area” can also be applied as it is.
The present invention is defined, and the symbol area a symbol occupancy 10-30% further explain the meaning of at least one symbol of 102mm ² ~918mm ^2. The first is that it has at least one large symbol. Second, if the “design area” is long but long (in the line direction of the take-up sheet), it is actually a paper wrinkle.・ Because there is little or no twist, the definition of “symbol occupancy” is defined as having a large symbol in the horizontal direction. Thirdly, even if a large number of small symbols exist at a density exceeding the gap into which a circle with a diameter of 4 mm enters, wrinkles or creases will not occur or are small, and this can be ignored.
"Pattern area" of the present invention is a 102mm ² ~918mm ^2, more preferably 177mm ² ~491mm ^2. In the present invention, a small design will not cause or reduce wrinkles and folds. This means ignoring this and targeting large symbols. In the case of an excessively large symbol, not only the “symbol occupancy rate” is often out of the range of 10 to 30%, but even if it is 30% or less of the upper limit of the “symbol occupancy rate” defined in the present invention, Cause wrinkles and problems.
The “symbol occupancy rate” of the present invention is 10 to 30%, but 13 to 22% is particularly desirable. If the “design occupancy” is excessively high, wrinkles and wrinkles will occur. The lower limit of the “symbol occupancy rate” is defined by comparison with the limit of 6% according to the prior art.
The “symbol area” and “symbol occupancy ratio” described above are defined from a macro viewpoint.
Such a large pattern is defined by the present invention from a microscopic point of view as a printing condition that prevents wrinkles and creases in the pattern and has no pattern collapse. The number of lines is 40 to 100, and the dot area ratio. Can be achieved under the condition of 15-50 ".
When the number of lines exceeds 100, solid printing is approached, and paper dust is involved at the time of printing, resulting in pattern collapse. If the number of lines is less than 40, the height of the convex portion is large, so that paper dust is mixed between the convex portions, resulting in pattern collapse.
When the halftone dot area ratio is less than 15, the height of the convex portion is large, so that paper dust is mixed between the convex portions, resulting in pattern collapse. When the halftone dot area ratio exceeds 50, it approaches solid printing and involves paper dust during printing, resulting in pattern collapse.
As solid printing approaches, it is good from the point of view of the pattern, but because the amount of ink applied within the area of the pattern increases, the paper is shrunk by the water of the water-based ink, and if the pattern is large, In addition, the paper is wrinkled and creased. For this reason, an excessive number of lines and a halftone dot area ratio are avoided and they are within a predetermined range.
On the other hand, the sharpness of the pattern will be reduced, but if paper dust is mixed between the convex parts and the pattern is prevented from being crushed, it will be somewhat "half-dotted" due to the ability of human eyes to identify. Even in such a case, the number of lines and the halftone dot area rate are avoided within a predetermined range in that they can be sufficiently recognized as one symbol.
As described above, in view of the fact that the object is sanitary thin paper, the present invention determines the optimum range by paying attention to the correlations of “design area” and “design occupancy”, the number of lines, and the dot area ratio. It will be apparent from the examples described later that the conventional example of sanitary thin paper is far beyond the conventional example.
Note that, in the printing, attention to the number of lines and the dot area ratio is also a matter that the present inventor knows, but the printing is in the case of printing on general paper, and as in the present invention, It is added that the printing pattern according to the present invention is not high-definition like printing on general paper, and is not selected from the viewpoint that wrinkles or creases occur on the paper. In addition, since printing on general paper does not cause wrinkles or creases on the paper, it is possible to print on a large pattern and on the entire surface of the paper. In the first place, the concept of the “design area” and “design occupancy” concept of the present invention There is no room for entry.
In the present invention, the target sanitary thin paper has a basis weight of 10 to 30 g / m ² , an elongation rate of 15 to 35%, the water-based ink has a viscosity of 10 to 50 cps, a vehicle of 5 to 25% by mass, and a water content of The effect is remarkable when printing under the condition of 95 to 75% by mass. Here, the rice tsubo is a value measured by JIS P 8124, the elongation is measured by JIS P 8113, and the viscosity is a value measured by a B-type viscometer.
Furthermore, when the water absorption of the sanitary thin paper of the present invention is 5 to 15 mm (JIS P 8141), the effects of the present invention are remarkably exhibited.
If necessary, the printed sheet can be embossed in an appropriate manner to enhance softness and bulkiness.

Next, examples and comparative examples of the present invention will be shown to clarify the effects of the present invention.
<Experimental example 1>
As a representative example including most of the commercial products as a base paper for the production of toilet paper rolls, the pulp is NBKP 30% · LBKP 70%, the rice tsubo is 15.5 g / m ² , and the elongation is 15%. Yes, a crepe of 22% and a water absorption of 10 mm were used. A floral pattern was printed on the base paper with a water-based ink having a viscosity of 20 cps, a vehicle of 5 mass%, and a water content of 95 mass%.
When printing, change the number of lines of dots, halftone dot area ratio, pattern occupancy rate, and pattern area, and perform sensory evaluation with 50 evaluators (appearance / design (pattern) sharpness / comprehensive evaluation) Went. The conditions and results are shown in Table 1. In addition, regarding the “appearance” and “design” borders, a five-step evaluation was made, with 5 being the best feeling, 1 in the order of decreasing numerical values, and 1 being the worst feeling. On the other hand, for “Comprehensive evaluation”, ◎ if you feel very good, ○ if you feel good, △ if you feel normal, × if you feel bad, × if you feel very bad It was set to 5 grade evaluation made into x. The symbol occupancy and the symbol area were changed by expanding and contracting the symbol shown in FIG. 1 as it was.

<Experimental example 2>
Printing was performed by changing the physical properties of the water-based ink under the printing conditions of Example 1 that were found to be optimal in Experimental Example 1. The results are shown in Table 2.

It is a partial top view of a sanitary thin paper. It is explanatory drawing of the number of lines of a halftone dot, and an area rate.

Explanation of symbols

  10 ... sanitary thin paper, 11 ... base part, 12 ... design part, d ... halftone dot.

Claims (3)

The sanitary thin paper surface, the number of lines 40 to 100, the halftone dot area ratio from 15 to 50% symbol occupancy occupied by symbols per 114mm width is and the symbol area is 10~30% 102mm ² ~918mm ² of at least one Printed sanitary thin paper characterized in that a predetermined pattern is printed with water-based ink under the condition having two patterns. The sanitary thin paper surface, the number of lines 40 to 100, the halftone dot area ratio from 15 to 50% symbol occupancy occupied by symbols per 114mm width is and the symbol area is 10~30% 102mm ² ~918mm ² of at least one A method for producing a sanitary thin paper for printing, characterized in that a predetermined pattern is printed with water-based ink under a condition having two patterns. The target sanitary thin paper has a basis weight of 10-30 g / m ² , an elongation of 15-35%, the water-based ink has a viscosity of 10-50 cps, a vehicle of 5-25% by mass, and a water content of 95-75% by mass. The manufacturing method of the printing sanitary thin paper of Claim 2 which prints on the conditions which are these.

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