JP7799417B2 - Paper Industrial Wipers - Google Patents

Description

The present invention relates to embossed paper industrial wipers.

Industrial wipers (hereinafter also referred to as paper industrial wipers) made from pulp or recycled paper (cellulose only, excluding nonwoven fabrics) are known.

Most products on the market are 2-6 ply, and come in a variety of embossing shapes (matched embossing, pin embossing, etc.) and product forms (pop-up type, quarter-fold type, handheld type, etc.).

Qualities required of paper industrial wipers include absorbency, usability (ease of wiping, volume in the hand), durability, etc.

As a prior art document for such paper industrial wipers, for example, Patent Document 1 discloses an industrial paper wipe characterized in that the constituent fibers are 100% pulp, the pulp contains 70 to 100 parts by weight of NBKP (softwood kraft pulp), and the pulp is made by adding 0.125 to 1.25 parts by weight of a wet strength agent and 0.01 to 0.5 parts by weight of a softener per 100 parts by weight of the constituent fibers, and the wipe is calendered, has a softness (handle-ometer method: in accordance with JIS L 1096E) value of 3.0 to 12.0 g, and has an MMD value of 7.0 to 20.0 on each side, and is stored in a state cut off for each use unit, and each of the cut and stored paper wipes is folded in half with the side with the larger mean deviation of the coefficient of friction (MMD) of the wipe surface inside, and is stacked so that the folded sides are in contact with each other and interlock with each other, and is removed by pop-up when used.
Furthermore, Patent Document 2 discloses an industrial wiping sheet that includes a laminate in which the number of laminated paper sheets is 4 or more and 8 or less, and at least one of the paper sheets in the surface layer of the laminate has a basis weight of 14.0 gsm to 19.0 gsm, the opening ratio of the paper sheet is 2.1% to 7.5%, and the water absorption capacity of the laminate is 300 g/m ² to 760 g/m ² .

Patent No. 5366596 Patent No. 5978100

Paper industrial wipers are embossed to improve absorbency, ease of wiping, and volume in the hand. Generally, the lower the embossed area ratio (the proportion of embossed areas relative to the entire wiper), the higher the embossed height remaining on the product, which is advantageous for absorbency, ease of wiping, and volume in the hand. Furthermore, many wiper products on the market have an embossed area ratio of less than 10%.

On the other hand, paper industrial wipers with a low embossed area ratio have the problem that the wiping feel (ease of wiping off dirt) varies between the front and back of the wiper (the embossed concave side and convex side), making them difficult to use. On the other hand, if the area ratio is increased (towards 50%), the difference in wiping feel between the front and back of the wiper becomes smaller, but the embossing on the product is less likely to remain (the embossing is easily crushed during the processing process), resulting in poor water absorbency and usability (volume when held in the hand), and the wiping feel also worsens on both the front and back of the wiper.
In addition to the embossing, the number of plies (plies) of the wiper base paper also has problems: if it is too few, it will be less durable and less absorbent, and if it is too many, it will be stiff and not comfortable to wipe with.

As a result, it was difficult with conventional technology to achieve a good balance between absorbency, usability (volume when held in the hand), durability, minimizing the difference in wiping feel between the front and back of the wiper (good wiping feel on both sides), and ensuring a good wiping feel.

The present invention was made in light of these circumstances, and aims to provide a paper industrial wiper that is excellent in water absorbency, usability (volume when held in the hand), durability, ease of wiping off dirt from both the front and back of the wiper, and excellent wiping comfort.

After extensive research, the inventors have discovered that by plying up a specified number of base sheets, embossing them to a specified area ratio and height, and integrating them into a single unit, and setting the basis weight within a specified range, it is possible to produce a paper industrial wiper that is excellent in water absorbency, usability (volume when held in the hand), and durability, and that is easy to wipe away dirt from both the front and back of the wiper, as well as providing an excellent wiping feel. This has led to the completion of the present invention. Specifically, the present invention provides the following:

(1) A first aspect of the present invention is a paper industrial wiper, which is made by plying one ply of base paper into three to four plies and embossing the plies to form an integrated body, characterized in that the basis weight of the wiper is 55.0 g/ ^m2 to 101.0 g/ ^m2 , the area ratio of the embossed surface area of the wiper is 25% to 50%, and the height of the embossments is 250 μm to 650 μm.

(2) A second aspect of the present invention is a paper industry wiper as described in (1), characterized in that the number of plies is three.

(3) A third aspect of the present invention is a paper industrial wiper as described in (1) or (2), characterized in that the paper thickness of the wiper is 400 μm or more per product ply and 800 μm or less per product ply.

(4) A fourth aspect of the present invention is a paper industrial wiper according to any one of (1) to (3), characterized in that the square root (GMT) of the product of the dry longitudinal tensile strength (DMDT) and the dry transverse tensile strength (DCDT) of the wiper according to JIS P 8113 is 10.4 N/25 mm or more and 25.0 N/25 mm or less.

(5) A fifth aspect of the present invention is a paper industry wiper according to any one of (1) to (4), characterized in that the area of one embossment of the embossments is 1.0 ^mm2 or more and 7.0 ^mm2 or less.

(6) A sixth aspect of the present invention is a paper industry wiper according to any one of (1) to (5), characterized in that the basis weight of the wiper after plying up, measured in a single ply state, is 18.7 g/ ^m2 or more and 26.7 g/ ^m2 or less.

(7) A seventh aspect of the present invention is a paper industrial wiper according to any one of (1) to (6), characterized in that the paper thickness of the non-embossed portion of the ply-up wiper, when measured in a 10-ply state, is 0.78 mm/10 plies or more and 1.25 mm/10 plies or less.

(8) The eighth aspect of the present invention is a paper industrial wiper according to any one of (1) to (7), characterized in that the square root (GMT) of the product of the dry longitudinal tensile strength (DMDT) and the dry transverse tensile strength (DCDT) according to JIS P 8113, measured in a single ply state after plying, is 5.0 N/25 mm or more and 11.9 N/25 mm or less.

(9) A ninth aspect of the present invention is a paper industrial wiper according to any one of (1) to (8), characterized in that the wiper is folded into four.

The present invention makes it possible to provide industrial paper wipers that are excellent in water absorbency, usability (volume when held in the hand), durability, ease of wiping off dirt from both the front and back of the wiper, and excellent wiping comfort.

FIG. 2 is a cross-sectional view of an embossed portion of the paper industrial wiper according to the present embodiment. FIG. 2 is a plan view of the embossed portion of the paper industrial wiper according to the present embodiment, viewed from the convex side.

The following describes in detail the form for carrying out the present invention (hereinafter simply referred to as the "present embodiment"). The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out with appropriate modifications within the scope of its gist.

In the drawings, identical elements will be given the same reference numerals, and duplicate explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

<Paper industrial wipers>
As shown in the cross-sectional view of Figure 1, the industrial paper wiper 1 according to this embodiment is made by plying (stacking) base paper 10 in three to four plies and embossing (by providing embossments 20) to integrate them. In this case, the number of plies is three or four, and three is more preferable. By using three or four plies, the industrial paper wiper 1 is strong and has appropriate water absorbency, and also has appropriate elasticity during wiping, resulting in a good wiping comfort.
The longitudinal dimension of the industrial paper wiper 1 is preferably 330 mm or more and 360 mm or less, and the width dimension is preferably 320 mm or more and 350 mm or less. The industrial paper wiper 1 may also be a so-called square type, in which the longitudinal dimension and the width dimension are equal. The product form of the industrial paper wiper 1 is not particularly limited as long as it is a form used in ordinary industrial wiper products, such as a pop-up type, a four-fold type, or a handy type, but a four-fold type is particularly preferred. When folded in four, the wiper has good water absorbency when used to wipe moisture off an object, and is also excellent in feel (volume when held in the hand).

The basis weight of the industrial paper wiper 1 is 55.0 g/ ^m2 or more and 101.0 g/ ^m2 or less, and preferably 61.2 g/ ^m2 or more and 86.7 g/ ^m2 or less. By setting the basis weight within the above numerical range, the industrial paper wiper 1 can be made to have good water absorbency, durability, and a good wiping feel.
Furthermore, the basis weight of the industrial paper wiper 1 after plying, when measured in a single-ply state, is preferably 18.7 g/ ^m2 or more and 26.7 g/ ^m2 or less, and more preferably 20.0 g/ ^m2 or more and 25.3 g/ ^m2 or less. By setting the basis weight in a single-ply state within the above numerical range, the industrial paper wiper 1 can be made to have water absorbency, durability, and a good wiping feel. In this case, "after plying" refers to the state after one ply of base paper has been plyed and embossed to integrate it. Note that the basis weight is measured in accordance with JIS P 8124.

The paper thickness T of the industrial paper wiper 1 is preferably 400 μm/product ply number or more and 800 μm/product ply number or less, and more preferably 500 μm/product ply number or more and 700 μm/product ply number or less. By setting the paper thickness T within the above numerical range, the industrial paper wiper 1 can be made to have an excellent feel in use (volume when held in the hand) and a good wiping sensation.
The "product ply number" in the unit of paper thickness T refers to measuring the paper thickness T without increasing or decreasing the plies of the product (the processed industrial paper wiper 1, not the base paper 10). The paper thickness T can be measured using a thickness gauge (for example, a dial thickness gauge "PEACOCK" manufactured by Ozaki Seisakusho) under the conditions of JIS P 8111 (23±1°C, 50±2% relative humidity) with a measurement load of 3.7 kPa and a probe diameter of 3 mm, by placing a sample (the industrial paper wiper 1) between the probe and the measuring table, and reading the gauge when the probe is lowered at a speed of 1 mm per second or less.

Furthermore, when the ply-up industrial paper wiper 1 is made into 10 plies, the paper thickness measured at the non-embossed portion is preferably 0.78 mm/10 plies or more and 1.25 mm/10 plies or less, and more preferably 0.89 mm/10 plies or more and 1.13 mm/10 plies or less. By keeping the paper thickness of the non-embossed portion of the 10 plies of the ply-up industrial paper wiper 1 within the above numerical range, the industrial paper wiper 1 can be made to have excellent usability (volume when held in the hand) and a good wiping feel. In this case, "10 plies" refers to the state in which the ply-up industrial paper wiper 1 is peeled off and returned to a single ply state, and then the returned single ply is stacked on top of each other to form 10 plies.

The square root GMT of the product of the dry longitudinal tensile strength DMDT and the dry transverse tensile strength DCDT of the industrial paper wiper 1 according to JIS P 8113 is preferably 10.4 N/25 mm or more and 25.0 N/25 mm or less, and more preferably 12.8 N/25 mm or more and 20.6 N/25 mm or less. When the GMT is within the above numerical range, the industrial paper wiper 1 can be made to be strong (durable).
Furthermore, when the ply-up industrial paper wiper 1 is measured in a single-ply state, the square root (GMT) of the dry longitudinal tensile strength (DMDT) and the dry transverse tensile strength (DCDT) according to JIS P 8113 is preferably 5.0 N/25 mm or more and 11.9 N/25 mm or less, and more preferably 6.1 N/25 mm or more and 9.8 N/25 mm or less. Having the GMT in a single-ply state within the above numerical range ensures that the industrial paper wiper 1 is strong (durable). The tensile strengths in each direction in a dry state are all measured in accordance with JIS P 8113, and the GMT is calculated as the square root of the product of these tensile strengths.

When adjusting the strength after ply-up, a method such as beating the base paper 10 with a DDR (double disc refiner) or adding a wet strength agent or a dry strength agent can be appropriately selected.
The wet strength agent is not particularly limited, but a polyamide polyamine epichlorohydrin-based agent is preferred. A dry strength agent may also be used, with a PAM-based dry strength agent being preferred. The wet strength agent may also contain an auxiliary agent, with an anionic polyacrylamide resin being preferred as the auxiliary agent for the wet strength agent. From the viewpoint of water absorption rate, the addition rate of the strength agent and auxiliary agent is preferably 1.0% or less based on the bone dry pulp weight. Adding a large amount of agent may result in poor water absorption rate.

(Embossed)
The embossing applied to the industrial paper wiper 1 according to this embodiment involves applying embossments 20 in a generally regular, repeated pattern to integrate multiple sheets of base paper 10. By applying the embossments 20, the concave side of the embossments 20 becomes a concave surface S, and the convex side becomes a convex surface B. Note that the processing form of the embossments 20 is not important, but a matched embossing method is preferred because the embossments 20 tend to remain on the industrial paper wiper 1.
The height of the portion of the industrial paper wiper 1 where the embossment 20 is applied, i.e., the height of the embossment 20 shown in Figure 1 (embossment height H), is 250 μm or more and 650 μm or less, and preferably 350 μm or more and 550 μm or less. When the embossment height H is within the above numerical range, the industrial paper wiper 1 can be made to have an excellent feel in use (volume when held in the hand) and a good wiping sensation. The embossment height H is determined by measuring the height of the embossment 20 of the industrial paper wiper 1 with a 3D microscope VR-3000 (manufactured by Keyence Corporation) and averaging the values measured at 30 points.

2, which shows the embossed portion of the industrial paper wiper 1 shown in FIG. 1 viewed from the convex surface B side, the area ratio of the embossments 20 on the industrial paper wiper 1 is preferably 25% to 50%, and more preferably 30% to 45%. When the area ratio is within the above numerical range, the industrial paper wiper 1 can be made to have an excellent feel in use (volume when held in the hand) and good ease of wiping off dirt from both the front and back of the wiper. The area ratio refers to the area ratio of the embossments 20 per unit area on the industrial paper wiper 1.
Furthermore, the area of one embossment of the embossments 20 is preferably 1.0 ^mm2 or more and 7.0 ^mm2 or less, and more preferably 1.8 ^mm2 or more and 5.0 ^mm2 or less. By having the area of one embossment within the above numerical range, the industrial paper wiper 1 can be made to have an even better feel in use (volume when held in the hand) and be even easier to wipe off dirt from both the front and back of the wiper.

The area of one embossment 20 is measured from the convex surface B side of the industrial paper wiper 1 using a microscope VHX-6000 (manufactured by Keyence Corporation), and the average value of 30 points is defined as the area of one embossment. The area ratio is calculated in embossed region A shown in FIG. 2 as (total area of embossments 20/area calculated by length x width of embossed region A) x 100 (%). In this case, the embossments 20 on the boundary line of embossed region A are counted as 1/2, and the embossments 20 at the four corners are counted as 1/4. Note that the embossing pattern shown in FIG. 2 is merely an example, and even if the embossing pattern is different, a repeating region (a region where the same pattern is repeated) as shown in FIG. 2 is selected and the area ratio is measured (i.e., the area ratio will be the same regardless of how the repeating region is surrounded).
Although the embossment 20 is substantially circular in FIG. 2, the shape of the embossment 20 is not particularly limited, and one or more shapes can be freely selected from the group consisting of circular, elliptical, polygonal, star-shaped, etc.

(base paper)
The base paper 10 (before plying) used to manufacture the paper industrial wiper 1 is not particularly limited in type of raw material, and one or a mixture of two or more types of bleached pulp, unbleached pulp, recycled raw materials derived from paper cartons, etc. can be used.
The raw material composition may be softwood kraft pulp, hardwood kraft pulp, or pulp recycled from milk cartons (MSF), but from the viewpoint of water absorbency, it is preferable to use 100% virgin pulp. From the viewpoint of the final strength of the paper industrial wiper 1, it is preferable to use 80% or more softwood kraft pulp, more preferably 90% or more, and even more preferably 100%.

As explained above, this embodiment makes it possible to provide a paper industrial wiper 1 that is excellent in water absorbency, usability (volume when held in the hand), durability, ease of wiping off dirt from both the front and back of the wiper, and excellent wiping comfort.

The present invention will be explained in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples in any way.

Under the conditions shown in Tables 1 and 2, paper industrial wipers (products) for Examples 1 to 13 and Comparative Examples 1 to 8 were produced and evaluated as follows. Note that all parameters other than those evaluated below were evaluated according to the standards or measurement methods described above.

(T.W.A.)
The water absorption was evaluated by the amount of water absorbed per unit area (TWA). The TWA values measured by the following measurement method were evaluated according to the following criteria.
240 g/m ² or more: Excellent (can absorb particularly large amounts of moisture)
220 g/m ² or more and less than 240 g/m ² : Good (can absorb a lot of moisture)
200 g/ ^m² or more and less than 220 g/ ^m² : Acceptable (no problem with moisture absorption)
Less than 200 g/ ^m2 : Unacceptable (low moisture absorption)

The total water absorption per unit area (T.W.A.) was measured by first cutting the obtained paper industrial wiper into a 76 x 76 mm square test piece and measuring the dry mass (W1). The test piece was then immersed in distilled water for 2 minutes, and then hung in an extended state (RH 100%) with one corner of the test piece positioned at the top. The top and the two adjacent corners were supported and the test piece was left for 30 minutes, after which the mass (W2) was measured. The value of (W2 - W1) was then calculated, and this value was converted to the water retention capacity (g/ ^m2 ) per 1 ^m2 of sample, which was used as the total water absorption per unit area (T.W.A.).

(Ease of wiping off dirt from each surface)
The ease of wiping off dirt and other materials on the concave and convex surfaces of paper industrial wipers was evaluated. Sensory evaluation was conducted by 60 people, who each rated the wiper on a scale of 1 to 5. The overall evaluation was based on the following criteria:
"Excellent ◎": Particularly easy to wipe off, dirt and the like comes off very easily. Average score of 60 people's evaluations is 4.0 points or more. "Good ○": Easy to wipe off, dirt and the like comes off easily. Average score is 3.0 points or more and less than 4.0 points. "Fair △": No problem in wiping off dirt and the like. Average score is 2.0 points or more and less than 3.0 points. "Poor ×": Difficult to wipe off, dirt is hard to come off. Average score is less than 2.0 points.

(Wiper blade handling)
A sensory evaluation of the feel of the paper industrial wipers when held in the hand was conducted by 60 people, who each rated them on a scale of 1 to 5. The overall evaluation was based on the following criteria:
"Excellent ◎": When you pick up the wiper, you feel a sense of volume, and you feel secure when using it. The average score of 60 people is 4.0 points or more. "Good ○": When you pick up the wiper, you feel a sense of volume, and you feel secure when using it. The average score of 60 people is 3.0 points or more and less than 4.0 points. "Fair △": When you pick up the wiper, you feel a slight sense of volume. There are no particular problems when using it. The average score of 60 people is 2.0 points or more and less than 3.0 points. "Poor ×": The wiper does not feel a sense of volume, it feels thin, and you cannot use it with confidence. The average score is less than 2.0 points.

(Wiper durability)
A sensory evaluation of durability when wiping an object with the wiper was conducted by 60 people, who each rated the wiper on a scale of 1 to 5. The overall evaluation was based on the following criteria:
"Excellent ◎": When wiping an object with the wiper, it feels particularly resistant to tearing. The average score of 60 people was 4.0 points or more. "Good ○": When wiping an object with the wiper, it feels particularly resistant to tearing. The average score was 3.0 points or more and less than 4.0 points. "Fair △": When wiping an object with the wiper, there is some tearing, but there is no problem in use. The average score was 2.0 points or more and less than 3.0 points. "Poor ×": When wiping an object, the wiper is easily torn and difficult to use. The average score was less than 2.0 points.

(Wiper wiping comfort)
A sensory evaluation of the wiping feel of the paper industrial wipers was conducted by 60 people, who each rated the wiper on a scale of 1 to 5. The overall evaluation was based on the following criteria:
"Excellent ◎": The wiper has elasticity, is particularly comfortable to wipe, and can wipe objects particularly smoothly. Average score of 60 people is 4.0 points or more. "Good ○": The wiper has moderate elasticity, is comfortable to wipe, and can wipe objects smoothly. Average score of 60 people is 3.0 points or more and less than 4.0 points. "Fair △": The wiper feels slightly elastic, and the wiping feel is at an acceptable level. Average score of 60 people is 2.0 points or more and less than 3.0 points. "Poor ×": The wiper does not feel elastic, and the wiping feel is poor. Average score is less than 2.0 points.

Table 1 shows the conditions and evaluation results for each example, and Table 2 shows the conditions and evaluation results for each comparative example. Each evaluation score of △ (fair) or higher was considered a pass.

From the above, it was at least confirmed that this example provides industrial paper wipers that are excellent in water absorbency, usability (volume when held in the hand), durability, ease of wiping off dirt from both the front and back of the wiper, and excellent wiping comfort.

1 Paper industrial wiper 10 Base paper 20 Embossment H Embossing height T Paper thickness S Concave surface B Convex surface A Embossed area

Claims (7)

A paper industrial wiper in which one ply of base paper is plied up to three to four plies, and then embossed to form an integrated structure,
the basis weight of the wiper is 55.0 g/ ^m2 or more and 101.0 g/ ^m2 or less, the area ratio of the embossed portion on the wiper is 25% or more and 50% or less, and the height of the embossment is 250 μm or more and 650 μm or less,
The paper thickness when measuring the non-embossed portion with the wiper after ply-up set to 10 plies is 0.78 mm/10 plies or more and 1.25 mm/10 plies or less,
A paper industrial wiper characterized in that, when the wiper after plying is measured in a single-ply state, the square root GMT of the product of the dry longitudinal tensile strength DMDT and the dry transverse tensile strength DCDT according to JIS P 8113 is 5.0 N/25 mm or more and 11.9 N/25 mm or less . The paper industry wiper according to claim 1, characterized in that the number of plies is three. The paper industrial wiper according to claim 1 or 2, characterized in that the wiper paper thickness is 400 μm or more per product ply and 800 μm or less per product ply. The paper industrial wiper according to any one of claims 1 to 3, characterized in that the square root (GMT) of the product of the dry longitudinal tensile strength (DMDT) and the dry transverse tensile strength (DCDT) of the wiper according to JIS P 8113 is 10.4 N/25 mm or more and 25.0 N/25 mm or less. 5. The wiper for the paper industry according to claim 1, wherein the area of each embossment is 1.0 ^mm2 or more and 7.0 ^mm2 or less. The paper industrial wiper according to any one of claims 1 to 5, characterized in that the wiper after plying has a basis weight of 18.7 g/ ^m2 or more and 26.7 g/ ^m2 or less when measured in a single ply state. 7. The paper industrial wiper according to claim 1, wherein the wiper is folded in four .