JP4585530B2 - Tissue paper - Google Patents

Description

  The present invention relates to a thin paper, and more particularly to a thin paper suitable as a wipe used for wiping industrial products, industrial products and parts thereof, test / laboratory instruments, and the like.

Wipes used for wiping industrial products, industrial products and their parts, test / laboratory equipment, etc. are required to have a tensile strength that can withstand wiping, and to generate very little lint (paper dust) and scratches. The
Japanese Patent Laid-Open No. 50-14872

Conventionally, a synthetic fiber mixed paper obtained by wet papermaking of a short fiber chemical fiber and pulp is generally used for this type of wipe.
However, synthetic fiber papers tend to generate lint when the gaps between the fibers are increased, and the wet strength decreases when the proportion of pulp fibers is increased. Therefore, in terms of bulkiness, softness, and liquid absorption. Many are inadequate.
Thus, the main problem of the present invention is to provide a thin paper that is not only easily rubbed and linted but also bulky, soft and liquid-absorbing, and has excellent wiping properties.

The present invention that has solved the above-described problems and the effects thereof are as follows.
<Invention of Claim 1>
Each layer is composed of three layers made of a synthetic fiber mixed paper in which chemical fibers and pulp are mixed, and is a dry wipe thin paper with a total weight of 40 to 180 g / m ² ,
Front and back layers each having a tear length specified in JIS P 8113 of 1.0 to 8.0 km , including heat-sealing fibers, and exhibiting a heat-sealing function in the range of 80 to 140 ° C . ;
An intermediate layer having a specific volume of ³ to 30 cm ³ / g including crimp fibers ;
A thin paper characterized in that adjacent layers are joined and integrated in the form of dots by heat seal embossing or ultrasonic sealing .

(Function and effect)
The thin paper of the present invention has sufficient strength at the time of wiping and less lint generation by setting the tear length of each layer on the front and back surfaces to 1.0 to 8.0 km.
And by making the specific volume of the intermediate | middle layer interposed between these into 3-30 cm < ³ > / g, while being bulky and improving a liquid absorptivity, softness is provided.
Then, these layers were joined together in the form of dots. As a result, the occurrence of littering and lint at the time of wiping hardly occurs, and it is bulky and soft, and the wiping property is extremely excellent.
Dry strength and wet strength are increased and lint generation is reduced.
The dryer part in a general papermaking process is generally performed at a predetermined temperature in the range of 80 to 140 ° C. or a predetermined temperature range. Accordingly, the thin paper having the structure of the present invention contains the heat-fusible fiber exhibiting the fusing function at the predetermined temperature or the like in the dry papermaking raw material, so that an appropriate amount of the heat-fusible fiber at the time of drying in the papermaking process. Can be produced by melting or softening the fiber and bonding the fibers together.
That is, the thin paper of the present invention can be easily manufactured by a general papermaking process, and it is not necessary to newly perform a process for melting a special heat-sealing fiber.
In addition, for example, heat-bonding fibers having other functions that melt or soften at the predetermined temperature or the upper limit temperature of the predetermined temperature range can be appropriately blended. It is possible to obtain an effective strength by heat fusion and an effect of preventing the occurrence of lint.
Furthermore, it becomes easy to heat-seal each layer by heat seal embossing or ultrasonic sealing after paper making.
Adhering in the form of dots by heat sealing effectively bonds the layers while ensuring bulkiness (enhancing water absorption and oil absorption).
In order to integrate the layers, it is possible to use an adhesive, but in order to suppress the occurrence of lint, it is necessary to apply the adhesive to the surface. In this case, the softness decreases, which is not desirable.
Although it is possible to join by the airlaid method or the mechanical entanglement method (spun lace method), there is a possibility that the rigidity may be excessively increased and the joining strength may not be sufficient.
On the other hand, if each layer is joined in the form of dots by heat sealing using heat-weldability, the risk of lint generation is remarkably reduced, and the rigidity is not excessively high although the joint strength is high.

  According to the present invention, there is provided a thin paper that has a tensile strength that can withstand wiping, is less prone to flaking and lint, and is bulky and soft.

The present invention will be further described below with reference to embodiments.
As shown in FIG. 1, the present invention has front and back layers 10 and 20 and an intermediate layer 30 interposed therebetween, and adjacent layers are joined and integrated.
Each layer can be formed by paper making using a known paper making technique. That is, it can be formed by drying a papermaking raw material containing pulp, chemical fibers, additives, and the like constituting a layer, which will be described later, with a drier, and then drying with a dryer.
You may perform smoothing processes, such as a calendar process, as needed.

  Each of the front and back layers is composed of a synthetic fiber mixed paper having a breaking length of 1.0 to 8.0 km as defined in JIS P8113. When the breaking length is less than 1.0 km, the fiber fluffing at the time of wiping cannot be sufficiently prevented, lint is easily generated, and the fiber is easily broken. When it exceeds 8.0 km, it becomes difficult to make it bulky and softness is lost. In particular, it is very difficult to make the paper bulky by wet papermaking using short fibers.

The front surface layer 10 and the back surface layer 20 preferably include heat-sealing fibers, and the constituent fibers are bonded to each other by the heat-sealing fibers.
The blending ratio of the heat-fusible fiber used for bonding the fibers is desirably 2 to 30% by mass. More preferably, it is the range of 5-15 mass%. If it is less than 2% by mass, the effect of preventing the occurrence of lint by the heat-bonding fiber blending is not sufficiently exhibited. When it exceeds 30 mass%, it becomes difficult to express softness.
In the surface layer and the back surface layer, the heat-sealing fiber used for bonding the fibers preferably exhibits a heat-sealing function at a predetermined temperature in a range of 80 to 140 ° C. or a predetermined temperature range. . Here, heat fusion refers to an adhesion function by melting or softening.
Therefore, in the surface layer and the back surface layer, the desirable composition in terms of blending the heat-fusible fibers is that the heat-sealing fibers exhibiting the heat-sealing function at a predetermined temperature in the range of 80 to 140 ° C. or a predetermined temperature range are 2 30% by mass is included.

In the dryer part in the paper making process, an appropriate temperature is generally selected from the temperature range of 80 to 140 ° C. Therefore, if the heat-sealing fibers that are melted at a predetermined temperature in the temperature range are mixed in the above range in the dry papermaking raw material, the fibers are bonded to each other by melting in the papermaking process, particularly in the dryer part. In addition, the lint generation preventing effect is suitably expressed.
In a series of papermaking processes such as drying with a dryer, an appropriate amount of heat-sealing fiber can be made to function as a binder.
Moreover, also when employ | adopting a heat seal in joining of each layer mentioned later, when it is set as the said mixture ratio and temperature range, the function as a binder which contributes to each layer joining is exhibited effectively. From the viewpoint of these production advantages, if the heat fusion temperature is excessively lower than the above range, it becomes hard due to excessive melting in the paper making process, etc., and if it is too high, the binder effect is not exhibited and the strength is low. .

The heat-sealable fiber is a composite binder fiber having a core-sheath structure in which a resin having a melting point lower than that of the core is used for the sheath, for example, core / sheath = PP (polypropylene) / PP (polypropylene), PP (polypropylene) / PE ( Polyethylene), composite fibers such as PET (polyethylene terephthalate) / low melting point PET, low melting point PET fibers, PP fibers, and the like. In particular, a composite fiber of PET is suitable. Of course, it may be a single-component heat-sealing fiber that does not have a core-sheath structure.
In addition, it is desirable that the heat-fusible fiber has a fiber degree of 1.0 to 5.0 dtex and a fiber length of 2 to 7 mm from the viewpoint of softness and strength maintenance.

The front surface layer 10 and the back surface layer 20 suitably include chemical fibers (hereinafter also referred to as main fibers) other than the above-mentioned heat-fusible fibers. The main fiber is preferably 15 to 50% by mass. The main fiber may have a fiber length of 2 to 6 mm and a fiber degree of 0.1 to 3 dtex. If the fiber degree is too small, the paper is easily entangled during paper making, and the texture is deteriorated. If the fiber degree is too large, the paper becomes inferior in smoothness.
Here, the main fiber is preferably one having substantially no heat-fusibility, but may be one having heat-fusibility. In the present invention, fibers that are not substantially used for bonding between fibers are main fibers. In the case where the main fiber includes a heat-fusible fiber, the fiber that exhibits a fusing function may be higher than the above-mentioned heat-fusible fiber by 15 ° C. or more.
Therefore, in each of the front and back layers in the form containing 2 to 15% by mass of the heat-fusible fiber that exhibits the heat-sealing function at the predetermined temperature in the range of 80 to 140 ° C. described above, In the present invention, the chemical fiber that does not exhibit the adhesion function is a main fiber in the present invention even if it is a heat-fusible chemical fiber.

On the other hand, the remainder other than the chemical fibers of the front surface layer 10 and the back surface layer 20 is preferably made of pulp. Specifically, the pulp includes mechanical pulp such as groundwood pulp (GP), pressure-rise groundwood pulp (PGW), and thermomechanical pulp (TMP), semi-chemical pulp (CP), and high yield unexposed kraft. Chemical pulp such as pulp (HNKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), and used paper such as deinking pulp (DIP) and waste pulp (WP) Pulp can be exemplified.
The said pulp can select and use 1 type, or 2 or more types.
Among these, chemical pulp containing no filler or foreign matter is preferable. NBKP is more preferable. In general, NBKP has a longer fiber length and a larger fiber thickness than LBKP. Therefore, the more NBKP, the higher the strength and bulkiness, and the better the water absorption and oil absorption properties attached to the front and back surfaces. -Good oil retention. Preferably, NBKP is contained in the layer in an amount of 30 to 70% by mass.
Here, the front surface layer 10 and the back surface layer 20 do not necessarily have to be configured in the same manner, and can be appropriately configured within the scope of the above description. However, since it becomes possible to favorably bond the layers with the heat-sealing fibers, it is preferable to use the same or similar heat-sealing temperatures for the heat-sealing fibers.

On the other hand, the front and back layers may be creped. Softness and bulkiness are imparted by creping.
Furthermore, a paper-making chemical such as a wet paper strength agent, a sticking agent, a dispersing agent, an adhesive, or a release agent may be appropriately used for the front and back layers.

On the other hand, the intermediate layer 30 is a paper layer, a nonwoven fabric layer, or a synthetic fiber mixed papermaking layer having a specific volume of ^{3 to} 30 cm ³ / g. A more preferable specific volume is 6 to 20 cm ³ / g. When the specific volume of the intermediate layer 30 is less than 3 cm ³ / g, bulkiness and softness are not expressed, and when it exceeds 30 cm ³ / g, practical strength is insufficient.
In particular, the intermediate layer is preferably a synthetic fiber mixed paper blended with 30 crimp fibers. It is excellent in terms of bulkiness and softness. If it is blended in the papermaking raw material, the specific volume can be facilitated.

Examples of the crimp fiber include, for example, a crimping process (both false twisting process and wooly process), which is performed by repeatedly repeating reverse and reverse twists and heat treatment for long fibers of polyester fiber, polypropylene fiber, polyethylene fiber, and polyethylene terephthalate fiber. It is suitable to be formed.
Among these, a PET crimp fiber formed by crimping polyethylene terephthalate fiber is preferable. In addition to the fibers formed by crimping chemical fibers, natural crimp fibers such as wool can also be used.

Also in the intermediate layer 30, it is preferable that heat-sealing fibers are blended. The heat-sealing fibers may be the same as those listed as included in the front and back layers. That is, a composite binder fiber having a core / sheath structure using a resin having a melting point lower than that of the core for the sheath, for example, composite fiber such as core / sheath = PET / low melting point PET, PP / PP, PP / PE, and composite fiber Non-single component low-melting point PET fibers, low-melting point PP fibers, and the like, and PET composite fibers are particularly suitable. Moreover, not only one type but two or more types of heat-sealing fibers can be used.
As the heat-sealing fiber used for the intermediate layer, those having a fiber thickness of 1.0 to 5.0 dtex and a fiber length of 2 to 6 mm are particularly suitable. In addition, the same kind as the front and back layers is not necessarily blended.
The proportion of the heat-sealing fibers in the intermediate layer 30 is less than that of the front surface layer 10 and the back surface layer 20, and is preferably less than 15% by mass. The upper limit is preferably less than 10% by mass. If it exceeds 15% by mass, the risk of becoming hard becomes extremely high.
Further, the intermediate layer 30 may also contain chemical fibers other than the heat-sealing fibers that function as crimp fibers and binders.

On the other hand, the remainder other than the chemical fibers of the intermediate layer 30 is preferably made of pulp, like the front and back layers 10 and 20. Pulp includes mechanical pulps such as groundwood pulp (GP), pressure-rise groundwood pulp (PGW), thermomechanical pulp (TMP), semi-chemical pulp (CP), high yield unexposed kraft pulp (HNKP), One type of chemical pulp such as softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), and used paper pulp such as deinking pulp (DIP) and waste pulp (WP) Or it can select and use 2 or more types.
In particular, a chemical pulp containing no filler or foreign matter is preferable, and NBKP is more preferable. In general, NBKP has a larger fiber thickness than LBKP, so that a larger amount of NBKP becomes bulky, and liquid absorbency and liquid retention are better. Preferably, NBKP is contained in the layer in an amount of 30 to 70% by mass.
The intermediate layer is preferably creped. Softens and increases bulk.
Furthermore, papermaking chemicals such as a wet paper strength agent, a viscosity agent, a dispersant, an adhesive, and a release agent may be used as appropriate.

40-180 g / m < ² > is preferable, and, as for the total rice floor of the surface layer 10, the back surface layer 20, and the intermediate | middle layer 30, More preferably, it is 70-150 g / m < ² >. If it is less than 40 g / m ² , it will be difficult to be bulky and it will also be difficult to develop liquid absorbency. If it exceeds 180 g / m ² , it becomes difficult to express softness.
Moreover, it is good for the ratio of the rice tsubo of each layer with respect to the total tsubo to be surface layer: intermediate layer: back surface layer = 10-30: 30-50: 10-30. If it is each within this range, the thin paper sheet as a whole can be bulky and soft while having strength that can withstand wiping.

On the other hand, it is desirable that the bonding and integration of the respective layers 10 to 30 is performed while exhibiting the heat-sealing function of the heat-sealing fibers by heat sealing or ultrasonic sealing, but the chemical solution spraying to dissolve the heat-sealing fibers. Or may be joined and integrated by an adhesive.
As a heat sealing mode, a known technique and apparatus such as a steel-rubber method or a steel-steel method can be used. In the case of the steel-rubber system, the rubber side is made of a Teflon-containing material to prevent the rubber itself from being melted by heat, and at the time of joining the layers of thin paper, only the desired part is sealed (sealed by heat sealing) )can do.

In the case of heat sealing, it is particularly desirable to be partially sealed by heat seal embossing that presses in a dotted pattern. The shape of one embossed recess E can be a polygon such as a rectangle, a square, or a rhombus, or a figure such as a star, a flower, or a leaf, but preferably has a diameter of 1 to 2 mm.
The area where embossing is performed should be 10 to 30% per area of one side of the thin paper, and if it is less than 10%, the layers of the thin paper may be insufficiently bonded and easily peeled off. . On the other hand, if it exceeds 30%, the thickness of the thin paper itself is reduced, and it feels hard when it is held in the hand, and the wiping property, water absorption and oil absorption properties cannot be fully exhibited.

In the case of an ultrasonic seal, it is particularly desirable to perform so as to form a dotted adhesive portion.
The scattered dot shape in the present invention includes not only a large number of dots but also a partial joining mode such as a large number of lattice shapes and spiral shapes.

"Evaluation test"
About the Example and comparative example of this invention, it tested about surface strength, softness, the amount of water absorption, and the water absorption speed. The test results are shown in Table 1 below.
Test methods and evaluation criteria such as physical properties of Examples and Comparative Examples are as follows.

<Example 1>
Example 1 is composed of front and back layers each having a fracture length of 1.80 km in length and 1.37 km in width, and an intermediate layer having a specific volume of 7.3 cm ³ / g. Performed by pressing heat seal embossing.
Each layer on the front and back surfaces is composed of 40% by mass of 0.1 dtex acrylic fiber (D122, 0.1 dtex, 6 mm, manufactured by Mitsubishi Rayon), core / sheath PET / PET fiber (heat fusion temperature 130 ° C., N720H, 2.2 dtex, 5 mm, Kuraray) (Made) 10% by mass and NBKP 50% by mass.
The intermediate layer is composed of 40% by mass of PET crimp fiber (TT04, 2.2 dtex, 5 mm, manufactured by Teijin Fiber), 10% by mass of core / sheath PET / PET fiber (thermal fusion temperature 130 ° C., N720H Kuraray), and NBKP 50% by mass. did.
<Example 2>
Example 2 is composed of front and back layers each having a tear length of 1.86 km and a width of 1.61 km, and an intermediate layer having a specific volume of 7.3 cm ³ / g. Performed by pressing heat seal embossing.
Each layer on the front and back surfaces is composed of a core-sheath PET / PET fiber (heat fusion temperature 130 ° C., N720H, 2.2 dtex, 5 mm, manufactured by Kuraray) 40% by mass, a core-sheath PET / PET fiber (heat fusion temperature 110 ° C., 4080, 1.1 dtex, 5 mm, made by Unitika fiber) 10% by mass and NBKP 50% by mass. In the drying process of the papermaking process, the dryer temperature was 115 ° C., and the core-sheathed PET / PET fiber having the heat fusion temperature of 110 ° C. was melted. It was put on to demonstrate the binder effect.
<Example 3>
In Example 3, the structures of the front and back layers and the intermediate layer were the same as those in Example 1, and the joining method of each layer was changed to an ultrasonic seal that pressed like dots.
<Example 4>
In Example 4, the structures of the front and back layers and the intermediate layer were the same as in Example 2, and the joining method of each layer was changed to an ultrasonic seal that pressed like dots.
<Example 5>
Example 5 is composed of front and back layers each having a tear length of 4.58 km and a width of 2.45 km, and an intermediate layer having a specific volume of 18.2 cm ³ / g. Performed by pressing heat seal embossing.
Each of the front and back layers is composed of 40% by mass of 0.1 dtex PET fiber (0.1 dtex, 5 mm, made by Teijin Fiber), core-sheath PET / PET fiber (heat fusion temperature 130 ° C., N720H, 2.2 dtex, 5 mm, made by Kuraray) 15 It was composed of 5% by mass, core / sheath PET / PET fiber (thermal fusion temperature 110 ° C., 4080, 1.1 dtex, 5 mm, manufactured by Unitika Fiber), and NBKP 40% by mass.
The intermediate layer is composed of PET crimp fiber (TT04, 2.2 dtex, 5 mm, made by Teijin Fiber) 40% by mass, core-sheath PET / PET fiber (heat fusion temperature 130 ° C., N720H Kuraray) 5% by mass, NBKP 55% by mass. did.

<Comparative Example 1>
In Comparative Example 1, the front and back layers were the same as those in Example 5, and constituted by an intermediate layer having a specific volume of 2.9 cm ³ / g, and the bonding of each layer was performed by heat seal embossing that pressed in the form of dots. .
The intermediate layer was composed of 10% by mass of core / sheath PET / PET fiber (heat fusion temperature 110 ° C., 4080, 1.1 dtex, 5 mm, manufactured by Unitika Fiber) and 90% by mass of NBKP.
<Comparative example 2>
It was set as the structure which laminated | stacked four layers of the structure similar to the surface layer of the comparative example 1 and Example 1. FIG. Bonding was performed by bonding and integrating the entire surface with a heat roll.
<Comparative Example 3>
Comparative Example 2 has a two-layer structure of a surface layer having a breaking length of 0.35 km in length and 0.29 km in width and a back layer made of synthetic fiber paper having a specific volume of 5.6 cm ³ / g.
The surface layer is made of PP fiber (PZ, 3.3 dtex, 5 mm, manufactured by Daiwabo Polytech) 40% by mass, core sheath PP / PE (heat fusion temperature 130 ° C., intac, 1.7 dtex, 5 mm, manufactured by ES Fiber Visions) 10 It comprised with the mass% and NBKP50%.
Bonding of the front and back layers was performed by pressing in a dotted manner with heat seal embossing.

(Surface strength)
The presence or absence of lint was evaluated. 50 times of friction test was conducted with a tester industry's scientific vibration type abrasion resistance tester, ◎ if there was no fluff at all, ○ if there was some fluff but no fiber was taken, entangled fiber lump was generated , And the surface was torn.
(Water absorption speed)
300 μl of water was placed on the sample with a pipette, and the time until it completely soaked into the sheet was measured. It was judged visually whether it soaked or not.
(Specific water absorption)
A sample cut into a 10 cm square is placed on a net, gently submerged in a container containing pure water, sufficiently infiltrated with water, pulled up, and further left for 30 seconds to measure the weight of the sample.
The value obtained by subtracting the weight of the sample at the time of drying from the measured weight was converted per 1 m ² of the sample, and the value obtained by dividing the value by the rice tsubo was defined as the specific water absorption amount. The evaluation criteria were 4.0 or higher for ◯ and less than 4.0 for X.
(soft)
The softness and smoothness of the surface were sensory evaluated. The subject actually took the sample and decided to make a judgment based on how he felt about softness and smoothness. A soft, smooth and easy-to-wipe feel was marked with ◎, a softness that was soft enough to wipe off was marked with ○, and a hard and hard-to-wipe mark was marked with X.

  As described above in detail, according to the present invention, there is provided a thin paper that has a tensile strength that can withstand wiping, is resistant to flaking and lint during wiping, and is bulky and soft.

  The present invention can also be used for wiping paper for oil and moisture such as cooking paper and kitchen paper.

It is a cross-sectional schematic diagram of the thin paper of this invention.

  DESCRIPTION OF SYMBOLS 10 ... Surface layer, 20 ... Back surface layer, 30 ... Intermediate | middle layer, E ... Embossing recessed part, X1 ... Thin paper.

Claims (1)

Each layer is composed of three layers made of a synthetic fiber mixed paper in which chemical fibers and pulp are mixed, and is a dry wipe thin paper with a total weight of 40 to 180 g / m ² ,
Front and back layers each having a tear length specified in JIS P 8113 of 1.0 to 8.0 km , including heat-sealing fibers, and exhibiting a heat-sealing function in the range of 80 to 140 ° C . ;
An intermediate layer having a specific volume of ³ to 30 cm ³ / g including crimp fibers ;
A thin paper characterized in that adjacent layers are joined and integrated in the form of dots by heat seal embossing or ultrasonic sealing .

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