JP2011225362A - Paper-made winding core - Google Patents

Abstract

In a paper core for winding a web, by forming a constant step in the axial direction with stable accuracy, the step mark of the web can be eliminated, and the productivity, cleanliness and discardability are excellent. A paper core is provided.
A paper core for winding a web, comprising a paper cylindrical core and a step formed on a peripheral surface of the cylindrical core and extending in parallel to the axial direction. The step forming member has a step portion having one end substantially equal to the thickness of the web, the other end having substantially no step with the outer peripheral surface of the core, and a density of 0. A paper core made of a paperboard of 20 g / cm ^{3 to} 0.90 g / cm ³ .
[Selection] Figure 1

Description

  The present invention relates to a paper core used for winding a web such as a film, sheet, foil, paper, and cloth.

A paper core is superior to a plastic core in terms of dimensional accuracy such as inner diameter and outer diameter and strength. Further, since the paper core can be recovered as used paper by collecting it after use, it is excellent in terms of disposal. Furthermore, it is economical because it is relatively inexpensive, and is used in a wide range of fields.
However, when the web is wound around a paper core, a step is generated between the end of the web at the start of winding and the portion wound on the web, thereby causing step marks, wrinkles, blocking, etc. There was a problem that the quality of the product deteriorated.
Therefore, as means for solving the above problems, Patent Document 1 discloses a core in which a sheet made of a cushioning material is wound around the outer peripheral surface.
However, although the cushioning material is effective for a film having a relatively thin thickness such as an optical application, the cushioning material is deformed in a web such as a general sheet, and it is difficult to eliminate the step.
Further, Patent Document 2 discloses. Disclosed is a core provided with a step portion extending in parallel along the axial direction of the core and having a height equal to the sheet-like thickness by cutting the outer peripheral surface using a grinder or a polishing machine. ing.
However, when there is even a slight deflection in the axial direction of the winding core, it is difficult to stably cut at a constant step in the axial direction. Further, since paper dust generated by cutting adheres not only to the outer peripheral surface of the paper tube but also to the inner peripheral surface and the end surface, there is a problem in cleanliness, and it is necessary to remove the paper dust after processing. In addition, fluffing of the cutting surface and turning of the paper tape are likely to occur, and the surface of the cutting region becomes uneven and may be transferred to the sheet.
Further, Patent Document 3 discloses a core in which a step is formed by fixing a wedge-shaped member having a specific hardness to the outer peripheral surface.
A paper core is generally manufactured by spiral winding in consideration of productivity and strength. In spiral winding, in consideration of productivity and production cost, the inner layer part is manufactured in a state in which the edge portions of adjacent strip-shaped paper tapes are in contact with each other, and the outer layer is manufactured by butting or overlapping. In the case of butting, a gap is generated between adjacent strip-shaped paper tapes due to problems in manufacturing technology. For this reason, the outer periphery of the core has a concave portion formed by the gap in a spiral shape. Further, when the adjacent belt-shaped paper tapes are overlapped on the outer layer, a convex portion due to the thickness of the belt-shaped paper tape spirally exists on the outer peripheral surface of the paper tube. As described above, there is an uneven portion in the axial direction of the outer peripheral surface of the core of the paper core, and even if a wedge-shaped member is fixed to the outer peripheral surface, an uneven portion is generated at the tip of the step portion. Therefore, it is considered difficult to stably form a certain level difference. When the web is wound up, there is a problem that a step mark remains remarkably in a portion wound on the uneven portion.

JP 2004-338818 A Japanese Utility Model Publication No. 6-80764 Japanese Patent Laid-Open No. 3-95075

  The present invention has been made in view of such a state of the art, and in a paper core for winding a web, by forming a constant step in the axial direction with stable accuracy, the step of the web is formed. It is an object of the present invention to provide a paper core that can eliminate traces and is excellent in productivity, cleanliness, and discardability.

As a result of intensive studies to solve the above problems, the present inventors have found that the paper core according to the first problem solving means is a paper core for winding a web, and is a paper cylinder. And a step forming member that is attached to the outer peripheral surface of the cylindrical core and that forms a step portion extending in parallel to the axial direction. One end of the step forming member is substantially equal to the thickness of the web. It has a stepped portion, the other end is formed so as not to have a step with the outer peripheral surface of the core body, and is made of paperboard having a density of 0.20 to 0.90 g / cm ³ .

  The paper winding core according to the second problem solving means is characterized in that, in the first problem solving means, the step forming member comprises a laminate in which at least two or more paperboards are laminated.

The paper winding core according to the third problem solving means is the first to second problem solving means, wherein the density of the inner paperboard of the laminate is 0.20 to 0.60 g / cm ³ and the outermost paperboard The density is 0.60 to 0.90 g / cm ³ .

According to the paper winding core of the first problem solving means, the step-shaped member is made of paperboard having a density of 0.20 to 0.90 g / cm ³ , so that the uneven portion existing on the outer peripheral surface of the cylindrical core body is formed. Occurrence of the uneven portion at the tip of the stepped portion can be suppressed, and a stepped portion with stable accuracy can be formed. Thereby, the web level | step difference trace of the part wound on the uneven | corrugated | grooved part which generate | occur | produces in the front-end | tip part of a level | step-difference part can be reduced especially. Further, by forming the core body and the step forming member with paper which is the same material, it is possible to provide a paper core excellent in discardability and recyclability.

  According to the paper core of the second problem solving means, since the step forming member is laminated with at least two paperboards, it is easy to process a thin paperboard as compared with a thick single layer paperboard, A paper core with improved productivity and workability can be provided. Moreover, it becomes possible to easily form a stepped portion having a thickness of 1 mm or more by laminating paperboard.

According to the paper core of the third problem solving means, the density of the inner paperboard of the laminate is 0.20 to 0.60 g / cm ³ and the density of the outermost paperboard is 0.60 to 0.90 g. Since / cm ³ , the inner layer exhibits a buffering effect and the outermost layer prevents deformation, so that a certain level difference can be formed with more stable accuracy.

It is a perspective view which shows schematic structure of the paper core of this invention. It is a fragmentary sectional view which shows the structure of the paper core of this invention. It is sectional drawing which shows the example of the level | step difference formation member of this invention.

Hereinafter, although the present invention is explained based on the preferred embodiment, the present invention is not limited only to an example.
The paper winding core 1 of the present invention includes a cylindrical core body 2 and a step forming member 3. The core body 2 is not particularly limited, but spiral winding produced by winding a plurality of strip-shaped paper tapes around a cylindrical iron core and fixing each layer with an adhesive improves productivity and strength. This is preferable.
The spirally wound core body 2 is formed by laminating a plurality of strip-shaped paper tapes wound spirally. Adjacent belt-like paper tapes inside and outside are bonded with an adhesive. The seams between the edge portions of each paper tape are butted and non-adhesive. There is a gap of about 0.5 to 1.5 mm in the axial direction between the adjacent strip-shaped paper tapes that face each other due to problems in manufacturing technology. When the outermost layer is manufactured by butting, a concave portion corresponding to the thickness of the paper tape exists spirally on the outer peripheral surface.
When the outermost layers are overlapped, the edge portions of the respective paper tapes are overlapped with each other, so that the convex portions 4 having the thickness of the paper tape are spirally formed on the outer peripheral surface of the overlapping edge portions. It will be. The overlapping edge portions are about 5 to 20 mm in the axial direction.

As shown in FIG. 2, the step forming member 3 of the present invention is attached to the outer peripheral surface of the core body 2 so that a step portion 5 is formed in parallel to the axial direction. The stepped portion 5 may be formed from one end surface of the core body to the other end surface, or may be formed only at a portion where the web is wound. However, it is preferable to form the core body 2 from one end surface to the other end surface in consideration of web winding workability.
The step forming member 3 includes a bottom surface 6 attached to the outer peripheral surface of the core body 2, a step portion 5 extending substantially perpendicularly from the bottom surface 6, and a relaxing surface 7 that forms the outer peripheral surface of the paper core 1 together with the step portion 5. It consists of.
The step portion 5 is a surface with which the winding start end portion of the web is abutted when the web is wound around the paper core 1, and the height of the step is substantially the same as the thickness of the web. “Substantially” refers to the thickness of the adhesive layer or double-sided tape used for sticking to the core.
The relaxation surface 7 is a surface that gently connects the tip 8 of the step portion and the outer peripheral surface of the core body 2. When the step forming member 3 is adhered to the core body 2, the relaxation surface 7 and the outer peripheral surface of the core body 2 are formed so as to have substantially no step. The fact that there is almost no step is about 0.03 to 0.20 mm in consideration of processing technology. Of the edge of the step forming member 3, the side opposite to the step portion 5 is tapered so that the joint between the relaxing surface 7 and the outer peripheral surface of the core body 2 is as smooth as possible. Either one of the relaxing surface 7 side and the bottom surface 6 side or both surfaces may be skived to form a taper shape. Preferably, only the bottom surface 6 side is skived. This is because the processed surface does not appear on the surface of the core 1, and thus the fluffing and the influence of the paper dust on the web can be reduced. Further, when an adhesive is used for adhering to the core body 2, the adhesiveness to the surface of the core body 2 is improved by roughening the surface of the bottom surface 6 that is an adhesive surface with the core body 2. For this reason, even if it is the level | step difference formation member 3 whose strong level | step difference is 1 mm or more, it can stick easily.

Adhesion of the step forming member 3 to the core 2 is not particularly limited, but an adhesive, a double-sided tape or the like is preferable. After using the paper core 1, it is preferable to use an adhesive (dextrin, starch, etc.) that is easy to disaggregate in consideration of recycling of waste paper.
The length in the circumferential direction of the step forming member 3 can be appropriately designed, but is preferably R / 12 to R / 2 with respect to the circumferential length R of the core body 2. This is because if the ratio is less than R / 12, the inclination of the buffer surface 7 becomes large, so that the joint between the outer peripheral surface of the core body 2 and the buffer surface 7 is not smooth, and a step mark due to the joint is generated. This is because when R / 2 is exceeded, it is difficult to attach the step forming member 3 with the long paper core 1 having a total length of more than 1 m.

The step forming member 3 is formed of paperboard having a density of 0.20 to 0.90 g / cm ³ . When the density is less than 0.20 g / cm ³ , the step forming member 3 is crushed when the web is wound, and when the density exceeds 0.90 g / cm ³ , the outer peripheral surface of the core body 2 is circumferentially formed. This is because it is difficult to bend along and difficult to stick. Here, the paperboard refers to paper tube base paper, liner paper, craft paper, sulfuric acid paper, high quality paper, low density paper, cardboard, and the like. Moreover, it is preferable that the paperboard of the step forming member 3 is formed so as to be in the MD direction along the axial direction of the core body 2. This is because it is easy to bend in the circumferential direction of the core body 2 and it is easy to stick to the outer peripheral surface of the core body 2. Here, the MD direction is the direction of the paperboard parallel to the traveling direction of the paperboard when paperboard is made with a paper machine.

  As shown in FIG. 3, the step forming member 3 is more preferably formed by laminating at least two paperboards. This is because productivity is improved by laminating thin paperboard after skiving, compared to skiving a thick single-layer paperboard. Moreover, it becomes possible to deal with a thick web by laminating in multiple layers. The layers can be laminated with an adhesive, double-sided tape, or the like. When laminating, the same paperboard may be laminated, or paperboards having different densities and thicknesses may be combined and laminated.

Further, among the laminated body of the step forming members 3, the paperboard 9 having a density of 0.20 to 0.60 g / cm ³ is used for at least one layer which becomes the inner layer side when adhered to the core body 2, and the outermost layer. It is preferable to use a paperboard 10 having a density of 0.60-0.9.0 g / cm ³ . Due to the buffering effect of the paperboard 9 of 0.20 to 0.60 g / cm ³ , the unevenness due to the core body 2 can be eliminated, and further, 0.60 to 0.99.0 g / cm ³ of the outermost layer can be eliminated. This is because by using the paperboard 10 having a high density, deformation due to web winding pressure can be prevented.
As shown in FIG. 3A, the outermost paperboard 10 having a density of 0.60 to 0.99.0 g / cm ³ may be formed so as to cover the entire inner layer. Further, as shown in FIG. 3B, the inner surface of the paperboard 9 having a density of 0.20 to 0.60 g / cm ³ may be exposed in a portion of the relaxation surface 7 far from the stepped portion 5. Good. A paperboard 10 outermost layer in the density of 0.60~0.9.0g / cm ³ of a portion which connects the stepped portion 5 of at least mitigate surface 7, and, 0.20~0.60g / cm ³ in the inner layer It is sufficient that the paperboard 9 is laminated.
FIG. 3B shows that the joint between the relaxation surface 7 and the outer peripheral surface of the core body 2 becomes smoother due to the buffering effect of the paperboard 9 of 0.20 to 0.60 g / cm ³ , and the relaxation surface 7 and the core body. Web wrinkles at the joint with 2 can also be reduced.

The core of the present invention will be described more specifically with reference to examples.
[Examples 1 to 12]
A predetermined step-forming member was attached to a paper tube as a core body having an outer diameter of 110 mm, an inner diameter of 79 mm, and a total length of 150 mm with an adhesive to produce a paper tube core. Examples 1 to 6 were prepared by overlapping kraft paper (60 g / cm ² ) on the outermost layer of the paper tube. In Examples 7 to 12, liner paper (180 g / cm ² ) was used as the outermost layer of the paper tube, and the butt was used. After aging for 3 days under conditions of an air temperature of 23 degrees and a humidity of 50%, a vinyl chloride table sheet having a thickness of 1.0 mm and a width of 100 mm was wound with a winding tension of 50 kg / cm ² for 6 m. The sheet was unwound after one day under conditions of a temperature of 23 ° C. and a humidity of 50%, and step marks generated on the sheet were observed.
Table 1 and Table 2 show the results of measuring the number of windings of the web in which the step mark disappears and the step mark due to the uneven portion at the tip of the step portion due to the outer peripheral surface of the core material. Here, in the evaluation of the step mark by the uneven part, the mark that is indistinguishable from other step marks is ◯, the mark that the step mark is slightly conspicuous compared with the other part is △, and the step mark is compared with the other part. Those which occurred remarkably were marked with ×.
[Comparative Example 1]
The same test as the example was performed without attaching the step forming member to the paper tube having the same size as the example.
[Comparative Example 2]
The same test as in the example was performed by forming a step portion parallel to the axial direction by cutting the outer peripheral surface of the paper tube having the same dimensions as in the example with a width of 90 mm in the circumferential direction.

  In Examples 1 to 12, as compared with Comparative Examples 1 and 2, the number of windings until the step difference of the web due to the winding start end portion was reduced by half, which was greatly improved. In the example, the step mark due to the uneven part at the tip of the step part due to the outer peripheral surface of the core material was improved.

DESCRIPTION OF SYMBOLS 1 Paper winding core 2 Core body 3 Level | step difference formation member 4 Convex part 5 Level | step difference part 6 Bottom face 7 Relaxation surface 8 The front-end | tip of a step part

Claims (3)

A paper core for winding a web, a paper cylindrical core, and a step forming member that is attached to the outer peripheral surface of the cylindrical core and that forms a step extending parallel to the axial direction. Consists of
One end of the step forming member has a step portion substantially equal to the thickness of the web, and the other end has substantially no step with the outer peripheral surface of the core, and the density is 0.20 g / cm ³ to. A paper core made of 0.90 g / cm ³ paperboard.   2. The paper core according to claim 1, wherein the step forming member comprises a laminate in which at least two paperboards are laminated. The density of the inner layer of the paperboard of the laminate 0.20g ^/ cm ³ ~0.60g ^/ cm 3 or less, and it is the density of the outermost layer of the paperboard is 0.60g ^/ cm ³ ~0.90g ^/ cm 3 or less The paper core according to any one of claims 1 to 2, wherein the core is made of paper.

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