JP2003011586A - Erasing sheet for writing board eraser and writing board eraser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an erasing sheet for writing board eraser, which can wipe off not-yet dried writing with a few erasing times by suppressing the spreading of ink. SOLUTION: As the erasing sheet (11) for a writing board eraser (10), an non-woven fabric formed so as to include rayon fibers and preferably having a sucking-up height of 5 mm or more is employed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eraser for a writing plate for erasing writings such as characters and figures written with a marking pen on a writing plate (in particular, a whiteboard) having an ink impermeable writing surface. The present invention relates to an erasing sheet, and more particularly to an erasing sheet for an eraser for a writing plate that erases handwriting written on a writing plate with an aqueous erasable marking pen.

[0002]

2. Description of the Related Art With the spread of writing plates having an ink-impermeable writing surface, especially whiteboards, various ink compositions for marking pens suitable for writing on such writing plates have been developed. Further, various attempts have been made to improve an eraser for a writing plate (also simply referred to as “eraser”) that erases a handwriting written on an ink-impermeable writing surface. The conventional eraser for writing board will be described below by taking a whiteboard eraser for erasing the handwriting written on the whiteboard as an example.

As one of the commonly used whiteboard erasers, an erasing sheet for wiping off handwriting is detachably attached to the surface of an appropriate base material (for example, pad), and the base material to which the erasing sheet is attached is attached. There is a whiteboard eraser housed in a plastic case. In this whiteboard eraser, the erasing sheet is a consumable member and is replaced when the erasing surface becomes dirty, and the base material and case are used repeatedly. The wiping performance of such a whiteboard eraser is determined by the erasing sheet. Therefore, various types of erasing sheets have been proposed.

For example, Japanese Patent Application Laid-Open No. 11-170778 proposes to use a cotton spunlace nonwoven fabric as an erasing sheet. Japanese Patent Laid-Open No. 5-44
In Japanese Patent Publication No. 145, it is proposed to use a nonwoven fabric containing ultrafine fibers having an apparent density of 0.04 g / cm ³ or less as an erasing sheet. Actual Kaihei 3-2
In 3499, it is proposed to use a tax pan nonwoven fabric as an erasing sheet. Further, Japanese Utility Model Application Laid-Open No. 4-37398 proposes to use a nonwoven fabric containing ultrafine fibers obtained by dividing and entanglement of splittable conjugate fibers as an erasing sheet.

[0005]

Various performances are required for the whiteboard eraser. One of them is to erase the handwriting immediately after writing with a smaller number of times of erasing (the number of times of rubbing the handwriting).

The handwriting immediately after writing (that is, the ink on the whiteboard) contains the solvent and is in a non-dried state.
Therefore, if this is rubbed with an eraser, the ink may be spread on the whiteboard by the eraser, and the handwriting may not be erased. This is particularly noticeable for the handwriting written with the water-based erasable marking pen. The ink used for the water-based erasable marking pen is
It is a water-based ink containing water as the main solvent, and the handwriting written on the whiteboard is erasable. Water-based ink
Compared to oil-based inks containing an organic solvent as a main solvent, the solvent (water) is less likely to evaporate and dries less. Therefore, the handwriting of the water-based erasable marking pen is hard to be erased immediately after writing. The same applies to the case where a handwriting written on another writing plate (for example, a glass plate) whose writing surface is impermeable to ink is erased.

The ink of the water-based erasable marking pen is a composition containing, for example, a colorant, a film-forming resin and a release agent in addition to water as a main solvent, and does not contain a large amount of organic solvent. Therefore, the water-based erasable marking pen has an advantage that the odor during use is less than that of the oil-based erasable marking pen. Due to these advantages, water-based erasable marking pens are expected to become even more popular in the future. However, as described above, the water-based erasable marking pen has a disadvantage that it is inferior in usability because its erasability is inferior to that of the oil-based erasable marking pen. This has contributed to the avoidance of water-based erasable marking pens. In order to avoid such inconvenience, development of a water-based ink that can be easily erased immediately after writing is being promoted, but it has not been realized yet that the water-based ink has the same erasability as the oil-based ink.

In view of the fact that it is difficult to improve the erasability of the water-based ink itself, the present inventors have made the construction of the eraser for a writing plate suitable for erasing the handwriting with a water-based erasable marking pen. As a result of repeated studies to eliminate the disadvantages of the water-based erasable marking pen,
The present invention has been devised.

[0009]

The erasing sheet for erasers for writing boards of the present invention (also simply referred to as "erasing sheet") comprises a nonwoven fabric containing rayon fibers. The erasing sheet of the present invention preferably contains 10% by mass of rayon fiber.
The above content is contained, and more preferably, 72 mass% or more of rayon fiber is contained. The erasing sheet of the present invention preferably comprises a non-woven fabric containing rayon fibers in an amount of 10 g / m ² or more, more preferably 50 g / m ² or more.

The non-woven fabric constituting the erasing sheet of the present invention is characterized by containing rayon fibers. With this feature, the erasing sheet of the present invention can wipe the undried handwriting immediately after writing with a smaller number of times of erasing.

In particular, the erasing sheet of the present invention is difficult to spread the ink on the writing plate even if the handwriting written with a water-based ink, which takes time to evaporate the solvent, is rubbed, and this is erased with a small number of erasing. be able to. Therefore, the erasing sheet of the present invention is particularly suitable for erasing the handwriting of an aqueous erasable marking pen.

The non-woven fabric constituting the erasing sheet of the present invention preferably has a suction height of 5 mm or more. If the suction height is less than 5 mm, it is difficult for the undried ink to transfer from the writing plate to the erasing sheet, and the erasing frequency increases. Here, the siphoning height means the height of the water siphoned by the sample while left standing for 1 minute with one end of the sample having a width of 2 cm being in contact with the water surface.

The erasing sheet of the present invention is preferably a hydroentangled nonwoven fabric or a needle punched nonwoven fabric. A hydroentangled nonwoven fabric is also called a spunlaced nonwoven fabric, and is manufactured by jetting a high-pressure water stream onto a fiber web to entangle fibers three-dimensionally. The needle-punched nonwoven fabric is manufactured by intertwining fibers of a fiber web with a needle. The hydroentangled non-woven fabric and the needle punched non-woven fabric produced as described above do not have the fixing points of the fibers due to the melting of the adhesive or the fibers.
Nonwoven fabrics, where there are no sticking points between the fibers, have a high wicking height and therefore a better wiping performance.

An oil agent may be attached to the surface of the fibers constituting the needle punched nonwoven fabric in order to improve the working efficiency of the needle punched. The non-woven fabric to which the oil agent is attached tends to have a smaller suction height than the non-woven fabric to which the oil agent is not attached. Therefore, when using a needle punched non-woven fabric to which an oil agent is attached as an erasing sheet, remove the oil agent as necessary (deoiling).
Is preferably carried out. By performing deoiling, the water absorption of the non-woven fabric is improved, and as a result, the erasability of handwriting, especially undried handwriting, is also improved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The erasing sheet of the present invention comprises a non-woven fabric containing rayon fibers. By including the rayon fiber, the erasing sheet of the present invention has an improved ability to wipe undried handwriting. The wiping property of undried handwriting tends to improve as the proportion of rayon fibers in the non-woven fabric increases or the mass of rayon fibers contained in the non-woven fabric increases. Therefore, in the erasing sheet of the present invention, the mixing ratio of rayon fibers is preferably 10% by mass or more, and more preferably 72% by mass or more. The amount of rayon fiber contained in the non-woven fabric is 1 m.
It is preferably 10 g or more per ^{2 and} more preferably 50 g or more per 1 m ² . More preferably, the erasing sheet is composed of a non-woven fabric composed of rayon fibers only.

The non-woven fabric constituting the erasing sheet of the present invention can be selected from non-woven fabrics manufactured by a conventional method using rayon fibers conventionally used for manufacturing non-woven fabrics. The type of rayon fiber used as the raw material of the nonwoven fabric is not particularly limited, and may be any of viscose rayon, polynosic, and cuprammonium rayon (cupra). The fineness and length of the rayon fiber are selected in consideration of the flexibility and strength of the finally obtained nonwoven fabric. For example, when the erasing sheet is a hydroentangled non-woven fabric or a needle punched non-woven fabric, the rayon fibers have a fineness of 0.5 to 9 dtex and 10 to 10
It is preferred that it has a length of 0 mm. The rayon fibers may have a modified cross section. The use of rayon fibers having a modified cross section can further improve the wiping performance of the erasing sheet.

When the erasing sheet is composed of rayon fibers and other fibers, the other fibers are selected from polyolefins such as polypropylene and polyethylene, polyester, cotton, nylon, acrylic, polyurethane and the like. It may be one or more fibers. The fineness and length of these fibers are also determined in consideration of the flexibility and strength of the finally obtained nonwoven fabric. For example, when the erasing sheet is a hydroentangled nonwoven fabric or a needle punched nonwoven fabric, the fineness of these fibers is preferably 0.5 to 10 dtex and the length is 10 to 100 mm. The rayon fiber and the other fiber may be included in the nonwoven fabric in a mixed form, or may be included in the nonwoven fabric in a laminated form.

The non-woven fabric constituting the erasing sheet of the present invention is a non-woven fabric manufactured by a usual manufacturing method.
The non-woven fabric may be, for example, a hydroentangled non-woven fabric, a needle-punched non-woven fabric, a thermal bond non-woven fabric, a chemical bond non-woven fabric or a spun bond non-woven fabric. As described above, the hydroentangled non-woven fabric and the needle punched non-woven fabric are suitable for the erasing sheet because the non-woven fabric can be produced without forming the fixing points of the fibers. In particular, the hydroentangled nonwoven fabric is preferably used because it is flexible and easily attached to and detached from the eraser.

The hydroentangled nonwoven fabric is produced by jetting a high-pressure water stream of 294 kPa to 19600 kPa onto a fiber web arranged on a suitable support. At this time, a non-woven fabric having through holes can be obtained by using a support having projections or a coarse mesh screen as the support. Nonwoven fabrics having through holes can also be used as the erasing sheet. However, when the size of the through holes is large or the number of the through holes is large, the ink easily passes through the through holes, and therefore, for example, when such a sheet is attached to the base material and used, the base material may be contaminated. In addition, the ink holding property tends to decrease. Therefore, the nonwoven fabric having through holes preferably has less than 30 through holes having a diameter of less than 3 mm per cm ² .

The needle punched non-woven fabric and the hydroentangled non-woven fabric may be those in which fibers are partially fixed to each other. For example, when fibers that are melted by heating, such as polyester, polyethylene, or polypropylene fibers, are used together with rayon fibers, some of them may be melted and the fibers may be fixed to each other at the point where the fibers come into contact with each other. Alternatively, the fibers may be secured together using a suitable adhesive. By fixing the fibers to each other, the strength and abrasion resistance of the nonwoven fabric can be improved. However, the greater the number of sticking points, the smaller the suction height, which reduces the wiping performance. Therefore, when the polyester or the like is melted by heating, it is necessary to appropriately select the heat treatment condition at the time of heating in consideration of the balance between the improvement of the strength of the nonwoven fabric and the wiping performance.

The non-woven fabric preferably has a basis weight of 30 to 180 g / m ² . If the basis weight is small, the holding power of the wiped ink (erased dust) tends to decrease.
Even if the basis weight is too large, the holding power of the wiped ink is lowered. This is because when the basis weight is large, the mesh of the nonwoven fabric becomes too clogged when the thickness of the nonwoven fabric is within the range described below.

The thickness of the non-woven fabric is preferably 0.1 mm or more. If the thickness is small, the holding power of the wiped ink may be reduced, and the ink may pass through the nonwoven fabric and stain the base material and the like located under the nonwoven fabric. The preferable upper limit of the thickness of the nonwoven fabric varies depending on the usage form of the nonwoven fabric in the eraser for writing boards. For example, as will be described later, when a non-woven fabric is detachably attached to a body as an erasing sheet to form an eraser, or when an eraser is formed by stacking a plurality of sheets and removing them one by one when the erasing surface becomes dirty. The thickness of the non-woven fabric is preferably 3 mm or less. In those erasers, when the thickness of the nonwoven fabric is large, there arises a disadvantage that the nonwoven fabric as the erasing sheet cannot be smoothly attached or detached or cannot be peeled off. Further, as will be described later, when the non-woven fabric is fixed to the body as an erasing sheet with an adhesive or the like to form an eraser, or when the non-woven fabric is used as it is as the erasing sheet without being attached to the body or the like, the non-woven fabric is attached and detached. Alternatively, the thickness of the non-woven fabric may be large because it does not require a peeling operation, and specifically, it is preferably 5 mm or less.

The non-woven fabric may have a single-layer structure or a multi-layer structure. In the case of a multilayer structure, it is preferable that the nonwoven fabric described above forms a surface layer (eraser erasing surface). That is, rayon fibers are included in the layer (surface layer) that constitutes the exposed surface. In that case, the layer located below the surface layer may be a layer containing no rayon fiber.

As described above, the nonwoven fabric constituting the erasing sheet of the present invention preferably has a suction height of 5 mm or more. The suction height is one of the indexes showing the water absorption of the nonwoven fabric. The erasing sheet of the present invention more preferably has a suction height of 35 mm or more.

The non-woven fabric described above is used as an erasing sheet by being attached to the body of an ordinary writing plate eraser (for example, whiteboard eraser). The erasing sheet can be removably attached to an appropriate substrate (for example, pad) (12a) as shown in FIG. 1, and the erasing sheet (11) is attached to the substrate (12a).
Is housed in a case (12b) and eraser (1
0) constitutes. As a method for attaching and detaching the erasing sheet, any conventionally used method can be adopted.

Alternatively, several to ten or more erasing sheets of the present invention may be stacked to form an eraser which can be peeled off one by one when the erasing surface is soiled. Such an eraser is constructed by releasably bonding and erasing the erasing sheets of the present invention, and attaching the laminated one to the body of the eraser. The erasing sheets of the present invention are detachably joined by, for example, needle punching in a laminated state to entangle fibers between the layers.

Alternatively, the eraser sheet of the present invention may be fixed to the body of the eraser with an adhesive or the like (that is, not to be removable) to form the eraser.
The erasing sheet of the present invention may be used as it is as a cloth without being attached to the body or the like.

According to the eraser including the erasing sheet of the present invention, it is possible to erase undried handwriting written with the water-based erasable marking pen with a smaller number of erasing times.
The erasing sheet of the present invention is also suitable for erasing handwriting written with an oil-based erasable marking pen that has a faster drying rate than handwriting written with an aqueous erasable marking pen.

The erasing sheet of the present invention can also be used to erase handwriting written on any type of writing plate having an ink impermeable writing surface. Therefore, the eraser equipped with the erasing sheet of the present invention is a whiteboard having a enamel writing surface, a whiteboard having a writing surface formed of a fluororesin coating, a sheet-shaped whiteboard, an electronic whiteboard, and glass. It is possible to easily erase even the handwriting written on any writing plate or the like having the surface as the writing surface.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples. (Examples 1 to 8 and Comparative Examples 1 to 8) In each Example and each Comparative Example, the type of fiber, the mixing ratio (% by mass) of fiber
A non-woven fabric having a basis weight, thickness, and rayon fiber content contained in the non-woven fabric as shown in Tables 1 and 2 was prepared.

In Tables 1 and 2, "needle punch" in the column of manufacturing method means that it was manufactured by the needle punching method, and "hydroentanglement" means that it was manufactured by the hydroentangling method. What is called "bond" means that the fibers are manufactured by a method of fixing the fibers to each other with an adhesive, and what is called "thermal bond" means that the fibers are manufactured by a method of thermally bonding the fibers to each other.

The suction height of the non-woven fabric used in each example and each comparative example was cut into a width of 2 cm to prepare a strip-shaped sample, and one end of the sample was brought into contact with the water surface for 1 minute. After standing, it was measured by a method of measuring the height of water sucked up by the sample.

As shown in FIG. 1, the prepared non-woven fabric is used as a erasing sheet (11) as a base material (pad) (12a) of a commercially available whiteboard eraser (“Sakura whiteboard eraser WDE-BS” manufactured by Sakura Crepas). The eraser (10) for evaluation of the wiping performance was obtained by mounting the eraser on a case (12b) and attaching it to a case (12b).
It had an erased surface of × 3 cm.

The wiping performance was evaluated in an environment of a temperature of 20 ° C. and a humidity of 65% according to the following procedure. First, the writing surface of the whiteboard was washed with alcohol and dried. Then, using a water-based erasable marking pen, a spiral (2 cm in diameter) (2 cm) was placed on the whiteboard (20) as shown in FIG.
I wrote down 1). Five seconds after writing, a load of 0.85 kPa (8.68 gf / cm ² ) was applied to the eraser, and the eraser was reciprocated so as to rub the handwriting on the handwriting. The wiping performance of the eraser of each example and each comparative example is ◎ when the handwriting is completely erased when the eraser is reciprocated 10 times, and the eraser is set to 1
When the handwriting was completely erased after reciprocating 5 times, it was evaluated as ◯, and when the eraser was not completely erased even after reciprocating 15 times, it was evaluated as x.

The evaluation of the wiping performance was carried out using a sheet-shaped white board (“One-touch white board” manufactured by Sakura Crepas Co., Ltd.) whose writing surface is coated with a fluororesin. The marking pen used for writing is "Aqueous white board marker ZBK-M (black)" manufactured by Sakura Crepas.

Tables 1 and 2 show the constitution of the non-woven fabric used as the erasing sheet in each example and each comparative example, the suction height of the non-woven fabric, and the wiping performance of the erasing sheet.

[0037]

[Table 1]

[0038]

[Table 2]

The erasers of Examples 1 to 8 all showed excellent wiping performance as compared with Comparative Examples 1 to 8. It is considered that this is because rayon fibers were included in the erasing sheet in any of the examples. The erasers of Examples 1 to 3 using the non-woven fabric in which the mixing ratio of the rayon fiber is 72% by mass or more and the content of the rayon fiber is 50 g / m ² or more showed particularly excellent wiping performance. The eraser of Example 4 is slightly inferior to Example 2 in wiping performance, even though the content of rayon fibers in the nonwoven fabric is larger than that of Example 2. It is considered that this is because the nonwoven fabric used in Example 2 was a hydroentangled nonwoven fabric and the nonwoven fabric used in Example 4 was a chemical bond nonwoven fabric.

[0040]

The erasing sheet for eraser for writing board of the present invention is characterized by containing rayon fiber. According to the eraser for a writing plate equipped with an erasing sheet having such characteristics, it is possible to erase undried handwriting immediately after writing with a smaller number of erasures by suppressing the spread of ink. Therefore, the erasing sheet of the present invention is suitable for erasing handwriting written with a marking pen in which the solvent in the ink has a low volatility, particularly an aqueous erasable marking pen.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing an example of an eraser for a writing board of the present invention.

FIG. 2 is a schematic diagram showing the shape of handwriting written on a whiteboard when the number of times of erasing is measured in an example.

[Explanation of symbols]

10 ... eraser for writing board, 11 ... erasing sheet, 1
2a ... substrate (pad), 12b ... case, 20 ... whiteboard, 21 ... handwriting.

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Claims (8)

[Claims] 1. An erasing sheet for an eraser for a writing plate, which is made of a non-woven fabric containing rayon fibers. 2. The erasing sheet for an eraser for a writing plate according to claim 1, which is made of a non-woven fabric containing 10% by mass or more of rayon fibers. 3. The erasing sheet for an eraser for a writing plate according to claim 1, which is made of a non-woven fabric containing 10 g / m ² or more of rayon fibers. 4. The erasing sheet for an eraser for a writing plate according to claim 1, wherein the nonwoven fabric is a hydroentangled nonwoven fabric or a needle punched nonwoven fabric. 5. The suction height is 5 mm or more.
An erasing sheet for an eraser for a writing plate according to any one of 4 to 4. 6. The erasing sheet for an eraser for a writing board according to claim 1, which is for erasing a handwriting written on a whiteboard. 7. The erasing sheet for an eraser for a writing plate according to any one of claims 1 to 6, which is for erasing a handwriting of an aqueous erasable marking pen. 8. An eraser for a writing plate, comprising the erasing sheet for the eraser for a writing plate according to any one of claims 1 to 7.