JP2011178527A - Seamless paper tube and film roll object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seamless paper tube which can prevent a trace of winding (wrinkles of winding) from occurring at the winding start portion of a synthetic resin film or the like, which can suppress the occurrence of the weaving, and which is prevented from being loosened off, and also provide a film roll object. <P>SOLUTION: This seamless paper tube 1 is formed by smoothening the outer peripheral surface of a paper tube body 10 formed by spirally laminating a paper bands. The maximum cross sectional height (Wt) of the wave curve of the seamless paper tube 1 on the smoothened outer peripheral surface 2a is 30-60 μm. The film roll object is characterized in that a film is wrapped around the seamless paper tube 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a seamless paper tube and a film roll body.

A paper tube is generally used as the core of a wound product (roll body) such as a synthetic resin film.
The paper tube is manufactured by laminating paper strips in a spiral shape. In the manufacture of a paper tube, a concave portion (groove) is usually formed on a surface on which a synthetic resin film or the like is wound by a paper strip adjacent in the major axis direction of the paper tube.
When a thin and soft film is wound around a paper tube in which such a recess is formed, there is a problem in that a winding mark (curl) due to the recess is generated at the winding start portion of the film.
In order to solve this problem, a seamless paper tube in which the outer peripheral surface of the paper tube is smoothed has been proposed. For example, a synthetic resin putty layer is formed on the surface of a paper tube in which a concave portion is formed at the boundary between the side edges of the paper band, the concave portion is filled with the synthetic resin putty, and the surface of the synthetic resin putty layer is A smoothly polished paper tube core is disclosed (see Patent Document 1).

JP-A-8-12197

However, in the seamless paper tube described in Patent Document 1, since the surface of the synthetic resin putty layer is polished smoothly, the synthetic resin film and the like are easily slipped on the smoothed outer peripheral surface. Therefore, the inner layer side (the side in contact with the paper tube) such as the synthetic resin film in the roll body shifts in the long axis direction of the paper tube while maintaining the winding state (winding deviation) or the paper tube comes off from the roll body ( There is a problem that paper tube omission is likely to occur.
The present invention has been made in view of the above circumstances, and does not cause a winding mark (winding wrinkle) at a winding start portion of a synthetic resin film or the like, and the occurrence of winding deviation or paper tube omission is suppressed. It is an object to provide a seamless paper tube and a film roll body.

The present invention relates to a seamless paper tube obtained by smoothing the outer peripheral surface of a paper tube main body formed by laminating paper strips in a spiral shape, and the maximum cross-sectional height (Wt) of the waviness curve on the smoothed outer peripheral surface is A seamless paper tube having a thickness of 30 to 60 μm.
The film roll body of the present invention is characterized in that a film is wound around the seamless paper tube of the present invention.

  According to the present invention, it is possible to provide a seamless paper tube and a film roll body in which no winding marks (winding wrinkles) are generated in a winding start portion of a synthetic resin film or the like, and the occurrence of winding deviation or paper tube slippage is suppressed. .

It is a perspective view which shows one Embodiment of the paper tube main body before smoothing an outer peripheral surface. It is a perspective view which shows one Embodiment of the seamless paper tube of this invention. It is a figure explaining the maximum cross-sectional height (Wt) of a wavy curve in the outer peripheral surface of a seamless paper tube.

<Seamless paper tube>
The seamless paper tube of the present invention is obtained by smoothing the outer peripheral surface of a paper tube body formed by laminating paper strips in a spiral shape.
Examples of the method for smoothing the outer peripheral surface of the paper tube main body include the following methods (i) to (iv).
(I) A method in which a coating liquid such as a synthetic resin is applied to the outer peripheral surface of the paper tube main body by various methods (for example, a brush, a doctor knife type coater, a spray, etc.).
(Ii) A method in which a belt-shaped synthetic resin or the like is spirally wound around the outer peripheral surface of the paper tube main body in a semi-solid state.
(Iii) A method of directly polishing the outer peripheral surface of the paper tube main body.
(Iv) A method in which a coating liquid such as a synthetic resin is applied to the outer peripheral surface of the paper tube main body by the method (i) and then the surface is polished.

FIG. 1 is a diagram showing an embodiment of a paper tube main body before the outer peripheral surface is smoothed.
In FIG. 1, a paper tube main body 10 is formed by laminating and stacking paper strips 11 in a spiral shape, and a recess 12 is formed by paper strips 11 and 11 adjacent in the long axis direction.

FIG. 2 is a view showing an embodiment of a seamless paper tube in which the outer peripheral surface of the paper tube main body shown in FIG. 1 is smoothed by the method (i). In FIG. 2, the section showing the cross section is a view showing a state in which a part of the synthetic resin layer 2 is broken, and the broken line shows the paper tube main body 10.
The seamless paper tube 1 of the present embodiment includes a paper tube main body 10 and a synthetic resin layer 2 formed on the entire outer peripheral surface of the paper tube main body 10.
In the seamless paper tube 1, the recess 12 is filled with a synthetic resin, and the entire outer peripheral surface of the paper tube main body 10 is covered with the synthetic resin layer 2 for smoothing.
Although not shown on the outer peripheral surface 2 a of the seamless paper tube 1, undulations (mountains, valleys) appear continuously in the major axis direction, and the outer peripheral surface 2 a has a predetermined “maximum cross-sectional height of a waviness curve ( Wt) ”.

(Paper tube body)
The types of paper constituting the paper strip 11 are conventionally known, and as will be described later, the winding caused by the overlap of the paper strip 11 wound on the outermost layer of the paper tube main body 10 in the lower layer of the outermost layer. Since the eyes 13 are easily raised, it is preferable to use paper having a low density.
The recess 12 is usually formed with a depth of about 0.1 to 1.0 mm and a width of about 0.05 to 0.3 mm.

(Synthetic resin layer)
Examples of the synthetic resin constituting the synthetic resin layer 2 include vinyl acetate resins, acrylic resins, urethane resins, and the like.

In the seamless paper tube of the present invention, the “maximum cross-sectional height (Wt) of the undulation curve” on the smoothed outer peripheral surface is obtained in accordance with JIS B 0601 _{: 2001} . Specifically, it is calculated by the following procedure.
Procedure (1): Using a stylus type surface roughness measuring machine, a measurement cross section obtained by digitizing the measurement curve obtained based on the trajectory when the stylus scans the outer circumference of the seamless paper tube in the major axis direction Get a curve.
Procedure (2): A sectional curve is obtained from the measured sectional curve.
Procedure (3): A waviness curve is obtained from the cross-sectional curve.
Procedure (4): The maximum section height (Wt) is calculated from the waviness curve.

FIG. 3 is a diagram for explaining the “maximum sectional height (Wt) of the undulation curve”.
The curve in FIG. 3 shows an example of a waviness curve indicating the surface roughness of the outer peripheral surface of the seamless paper tube. The maximum cross-sectional height (Wt) is calculated as follows.
First, λc, which is a cut-off value of the undulation curve, is set to 0.8 mm (the same length as the reference length Lr), λf, which is a high-frequency cut-off value, is set to 8 mm, and the evaluation length is set to 100 mm.
Next, the maximum section height (Wt) is calculated by obtaining the sum of the maximum value Zp of the peak height of the undulation curve and the maximum value Zv of the valley depth in the evaluation length.

In the seamless paper tube 1, the “maximum cross-sectional height (Wt) of the undulation curve” of the smoothed outer peripheral surface 2a is preferably 30 to 60 μm.
When the Wt is 30 μm or more, the occurrence of winding deviation or paper tube omission is suppressed, and when the Wt is 60 μm or less, when a synthetic resin film or the like is wound around the seamless paper tube 1, it appears on the outer peripheral surface 2a. Wounds (curves) due to the undulations that occur are less likely to occur.
The Wt can be adjusted by controlling the density of the paper constituting the paper band 11. Specifically, it is preferable to use low-density paper. For example, in the case of unbleached kraft paper, the paper density is preferably in the range of 0.50 to 0.82 (unit: g / cm ³ ). By controlling, the Wt can be easily adjusted within a predetermined range.
In the present invention, “paper density” indicates a value measured by a method in accordance with JIS P 8118.

The seamless paper tube 1 of the present embodiment uses a paper strip 11 made of low-density paper as described above. For example, the paper strip 11 is laminated on a mandrel while spirally winding the paper strip 11 from a plurality of directions. After the tube main body 10 is manufactured, it can be manufactured by filling the concave portion 12 with the synthetic resin and forming the synthetic resin layer 2 on the entire outer peripheral surface of the paper tube main body 10 by the method (i).
If necessary, after the synthetic resin layer 2 is formed, the surface (outer peripheral surface) of the synthetic resin layer 2 is maintained so that the “maximum cross-sectional height (Wt) of the undulation curve” on the outer peripheral surface 2a is maintained within a predetermined range. 2a) may be polished and smoothed using a grinder or the like.
In addition, the synthetic resin applied to the entire outer peripheral surface of the paper tube main body 10 may be cured by heat, drying, or the like. When an ultraviolet ray or radiation curable resin is used, a lamp of each energy ray is irradiated. Then, the synthetic resin may be cured.

According to the seamless paper tube of the present invention, no winding marks (winding wrinkles) are generated at the winding start portion of the synthetic resin film or the like, and occurrence of winding deviation or paper tube loss can be suppressed.
The inventors of the present invention have found that, by changing the density of the paper constituting the paper band, the effect of preventing the occurrence of winding slippage or slipping out of the paper tube or the like of the synthetic resin film can be obtained. And by further examination, by controlling the density of the paper and adjusting the “maximum cross-sectional height (Wt) of the undulation curve” on the outer peripheral surface of the seamless paper tube to a range of 30 to 60 μm, It has been found that the effect of suppressing the occurrence of winding misalignment or paper tube loss is obtained for the first time without causing a winding mark (curl) at the winding start portion.
In this way, it is estimated that the occurrence of winding deviation or paper tube omission is suppressed as follows.
That is, by controlling the density of the paper and using a lower density paper,
(1) On the outermost layer of the paper tube main body, the winding of the paper strip wound in the lower layer of the outermost layer is likely to be raised.
(2) Since the coating liquid such as synthetic resin applied to smooth the outer peripheral surface of the paper tube main body is easy to be impregnated, the shape raised on the outermost layer of the paper tube main body is the surface of the coating layer (seamless paper tube Of the outer peripheral surface).
As a result, undulations (swells) appear in the long axis direction periodically to some extent on the outer peripheral surface of the seamless paper tube. Further, the outer peripheral surface of the seamless paper tube has a predetermined “maximum cross-sectional height (Wt) of the waviness curve”, so that the friction between the outer peripheral surface of the seamless paper tube and the synthetic resin film is increased. Even if the outer peripheral surface of the tube is smooth to some extent, the synthetic resin film or the like is less likely to slip on the outer peripheral surface of the seamless paper tube.

<Film roll body>
In the film roll body of the present invention, a film is wound around the seamless paper tube of the present invention.

(the film)
Examples of the resin used for the film include polyolefin resin, vinyl chloride resin, polystyrene resin, polyester resin, polyamide resin, and the like.
These resins may be used individually by 1 type, and 2 or more types may be mixed and used for the film.

  Examples of the polyolefin resin include high-pressure low-density polyethylene, a copolymer of ethylene and an α-olefin having 4 to 8 carbon atoms, linear low-density polyethylene (L-LDPE) obtained using a metallocene catalyst, and ethylene. -Polyethylene resin such as vinyl acetate copolymer; Polypropylene resin such as polypropylene homopolymer, ethylene-propylene random copolymer, ethylene-butene-propylene copolymer, butene-propylene random copolymer; Examples include homopolymers, random copolymers of α-olefins having 2 to 20 carbon atoms and cyclic olefins, and graft-modified products thereof.

  Examples of the vinyl chloride resin include polyvinyl chloride having a number average degree of polymerization of about 800 to 2500 (preferably a number average degree of polymerization of about 1000 to 1800); ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer A copolymer mainly composed of vinyl chloride such as a vinyl chloride-halogenated olefin copolymer; the above polyvinyl chloride or a copolymer mainly composed of vinyl chloride and another compatible resin (for example, polyester resin, And epoxy resins, acrylic resins, vinyl acetate resins, urethane resins, acrylonitrile-styrene-butadiene copolymers, partially saponified polyvinyl alcohols, and the like.

Examples of polystyrene resins include styrene-butadiene-styrene block copolymers, styrene-butyl (meth) acrylate copolymers, transparent / impact polystyrene, GP polystyrene, styrene-butadiene thermoplastic elastomers, and the like. Can be mentioned.
Of these, styrene-butadiene-styrene block copolymers and styrene-butyl (meth) acrylate copolymers are preferred, and styrene-butadiene-styrene block copolymers are preferred. Is more preferable.
In addition, (meth) acrylate means one or both of acrylate or methacrylate.

Examples of the polyester resin include a polyester resin obtained by condensation polymerization of a dicarboxylic acid component and a diol component.
Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, and cyclohexanedicarboxylic acid. Of these, terephthalic acid is particularly preferable.
Examples of the diol component include 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, and the like. Of these, ethylene glycol is particularly preferable.
Specific examples of polyester resins obtained by condensation polymerization of a dicarboxylic acid component and a diol component include polyethylene terephthalate copolymerized with 10 to 40 mol% of 1,4-cyclohexanedimethanol; 0 to 25 mol% of isophthalic acid was copolymerized. General-purpose polyesters such as polyethylene terephthalate are listed.
Other polyester resins include polyesters obtained by condensation polymerization or ring-opening polymerization of hydroxycarboxylic acids such as lactic acid, hydroxybutyric acid, and polycaprolactone.

  Examples of polyamide-based resins include those obtained by ring-opening polymerization of cycloaliphatic lactams such as 6-nylon and 12-nylon; aliphatic diamines such as 6,6-nylon, 6,10-nylon, and 6,12-nylon Obtained by polycondensation of styrene and aliphatic dicarboxylic acid; polycondensation of aromatic diamine such as polycondensation product of m-xylenediamine and adipic acid and aliphatic dicarboxylic acid; p-phenylenediamine and terephthalic acid Examples include polycondensation products, polycondensation products of aromatic diamines and aromatic dicarboxylic acids such as polycondensation products of m-phenylenediamine and isophthalic acid; and polycondensation of amino acids such as 11-nylon.

In addition to the resin, the film may contain additives such as UV absorbers, anti-blocking agents, lubricants, antistatic flame retardants, colorants, lubricants, plasticizers, fillers, impact modifiers as necessary. It may be contained.
Further, the film may have a multilayer structure in order to improve physical properties, chemical properties, and the like. The multilayer film may have one or more foamed layers.
The film may be coated with an acrylic resin, urethane resin, polyamide, polyolefin, polyvinyl alcohol, polyvinylidene chloride, polyester, or the like, or may have a metal thin film formed by metal deposition.
Furthermore, the film may be subjected to a surface treatment such as corona treatment, plasma treatment, flame treatment, or the like; radiation treatment with ultraviolet rays, α rays, β rays, γ rays, electron beams, etc., in order to impart specific performance. Good.

  According to the film roll body of the present invention, even if a thin and soft synthetic resin film having a thickness of 50 to 500 μm, for example, is wound around the seamless paper tube of the present invention, it is wound around the winding start portion of the synthetic resin film or the like. Traces (winding habits) are not generated, and the occurrence of winding deviation or paper tube loss is suppressed.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
The paper tube used in this example and the film used to wind the paper tube are as follows.

(Paper tube)
As shown in Table 1, seamless paper tubes A to D having different maximum density of waviness (Wt) and paper density of the paper tube main body and general paper tubes that are not seamlessly processed are used. It was.
All of the paper tubes used had a length of 1212 mm, a wall thickness of 12 mm, and an inner diameter of 76.2 mm.
As the seamless paper tubes A to D, those prepared to have a thickness of 12 mm by polishing the surface of the same form as the seamless paper tube shown in FIG. 2 using a grinder were used.

(the film)
A multilayer film having a three-layer structure having an outer layer / intermediate layer / outer layer thickness ratio of 10/80/10 was prepared by a coextrusion method.
Next, this multilayer film was stretched 1.1 times in the vertical direction and 5 times in the horizontal direction at 85 ° C., and a multilayer heat-shrinkable film having a thickness of 40 μm (hereinafter simply referred to as “film” in this example). ) Was produced.
The following copolymers were used as materials for forming the outer layer and the intermediate layer on both sides, respectively.
Materials that form the outer layers on both sides:
A styrene-butadiene-styrene block copolymer having a butadiene unit content of 20% by mass (trade name: Asaflex 805, manufactured by Asahi Kasei Chemicals).
Material forming the intermediate layer:
27% by mass of the styrene-butadiene-styrene type block copolymer and a styrene-butyl acrylate copolymer having a butyl acrylate unit content of 23% by mass (manufactured by PS Japan, trade name: KD-350, Vicat softening point 66) C.) 70% by mass and a mixture of 3% by mass of a styrene-butadiene-styrene type block copolymer (product name: Toughprene 126, manufactured by Asahi Kasei Chemicals Co., Ltd.) having a butadiene unit content of 60% by mass.

[Maximum section height of waviness curve (Wt)]
The maximum cross-sectional height (Wt) of the undulation curve on the outer peripheral surface of the paper tube was calculated according to JIS B 0601 _{: 2001} according to the above-described procedures (1) to (4).
Specifically, using a surface roughness measuring machine (manufactured by Tokyo Seimitsu, product name: SURFCOM 480A), λc, which is a cutoff value of the undulation curve, is 0.8 mm (the same length as the reference length Lr), high frequency Wt (μm) on the outer peripheral surface of the paper tube was calculated by setting λf, which is a cut-off value, to 8 mm and an evaluation length of 100 mm. The results are shown in Table 1.

[Paper density of paper tube body]
In accordance with JIS P 8118, a fully automatic paper physical property measuring apparatus “AutoScan” (manufactured by Kumagai Riki Kogyo Co., Ltd.) was used. The density of the bleached kraft paper was measured, and the result is shown in Table 1 as the paper density (g / cm ³ ) of the paper tube main body.

<Example of production of film roll>
Example 1
Using a rewinder 513E (product name) manufactured by Gordo Kiko, three film rolls were manufactured by winding the above-mentioned film 3000 m having a width of 1200 mm around the seamless paper tube A while maintaining a predetermined tension.

(Examples 2-3, Comparative Examples 1-2)
Three film rolls were produced in the same manner as in Example 1 except that seamless paper tubes B to D and general paper tubes were used instead of seamless paper tubes A.

  In addition, when manufacturing the film roll body of each example, the temperature around the rewinding machine 513E (product name) was controlled to 18 to 22 ° C., and the relative humidity was controlled to 20 to 50% RH.

<Evaluation of various properties in film roll>
About the obtained film roll body, winding deviation, paper tube omission, and the surface property of the film were evaluated by the methods described below. The results are shown in Table 1.

[Out-of-winding / paper tube missing]
The film roll body was stored for one week in a room maintained at a temperature of 20 ° C. and a relative humidity of 50% RH. Thereafter, using “MY-BS-504” manufactured by Motoda Giken, the film roll was left to stand for 10 seconds in a state where the film roll was lifted so that the major axis direction became a top and bottom. At this time, the occurrence of winding deviation or paper tube slippage in the film roll body was observed and evaluated according to the following criteria.
○: Neither winding slippage nor paper tube omission was observed.
Δ: The downward winding deviation on the inner side of the film roll (side in contact with the paper tube) was 1 cm or less.
X: The whole film fell off from the film roll body, or the film roll inner layer side shifted downward, and a bamboo shoot-like winding slip occurred.

[Film surface properties]
After the film roll body was stored in a room maintained at an air temperature of 20 ° C. and a relative humidity of 50% RH for 1 week, all films were unwound from the film roll body. And the generation | occurrence | production condition of the winding mark (winding wrinkle) in the major axis direction from the beginning of winding of this unwound film to 10 m was observed, and the following references | standards evaluated.
○: No occurrence of winding marks (curly wrinkles) was observed.
X: Generation | occurrence | production of the winding mark (curly wrinkle) was recognized.

In the film rolls of Example 1 and Example 2, good results were obtained for both winding slippage, paper tube slippage, and film surface properties.
In the film roll body of Example 3, the surface property of the film was good, but a slight winding deviation occurred with no practical problem.
On the other hand, in the film roll body of Comparative Example 1, a bamboo shoot-like winding slip occurred.
Moreover, in the film roll body of Comparative Example 2, no winding slip or paper tube loss occurred, but a trace (curl) was observed at the beginning of winding of the film.

  The seamless paper tube of the present invention is particularly suitable as a wound core (roll body) such as a thin and soft synthetic resin film. The film roll body of the present invention is suitable as a wound product for heat shrink labels and heat shrink wrapping used for PET bottles and the like.

  DESCRIPTION OF SYMBOLS 1 Seamless paper tube 2 Synthetic resin layer 2a Outer peripheral surface 10 Paper tube main body 11 Paper strip 12 Recessed part 13 Roll

Claims (2)

In the seamless paper tube formed by smoothing the outer peripheral surface of the paper tube body formed by laminating paper strips in a spiral shape,
A seamless paper tube, wherein the maximum cross-sectional height (Wt) of the undulation curve on the smoothed outer peripheral surface is 30 to 60 µm.   A film roll body in which a film is wound around the seamless paper tube according to claim 1.

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