JP2903025B1 - Moisture proof paper - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To prevent a low molecular weight substance in a desiccant layer 2 from being transferred to PPC paper in contact with the PPC paper.
Provided is a moisture-proof paper 1 that can prevent a friction coefficient of PC paper from being reduced. SOLUTION: A moisture-proofing agent layer 2 is formed by applying a water-disintegratable moisture-proofing agent on a paper material 3. Filler 4 is blended in the desiccant. Since the bulk density of the filler 4 is 0.8 g / cm ³ or more and 2.0 g / cm ³ or less, the filler 4 does not settle during application, and a part of the filler 4 projects from the moisture-proof agent layer 2. When the PPC paper is wrapped with the moisture-proof paper 1, the protruding portion of the filler 4 comes into contact with the PPC paper, and the contact area between the base material 5 of the moisture-proof layer 2 and the PPC paper is suppressed. Therefore, the transfer of the low molecular weight substance from the moisture barrier layer 2 to the PPC paper is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof paper used for packaging plain paper copy paper and the like.

[0002]

2. Description of the Related Art When plain paper copy paper (hereinafter referred to as "PPC paper") used for dry copying absorbs moisture, the coefficient of friction increases, and a plurality of PPC papers are fed into a copier in a stacked state during copying. Double feed may occur. PPC paper is wrapped with moisture-proof paper to prevent moisture absorption during the distribution and storage stages of PPC paper. As this moisture-proof paper, a moisture-proof paper (hereinafter, also referred to as a laminated moisture-proof paper) in which a polyolefin such as polyethylene or polypropylene is laminated on a paper material with a thickness of about 15 micrometers to improve moisture permeability is conventionally used. . This moisture-proof paper is excellent in moisture permeability, but because it contains polyolefin, even if it is used as recycled paper, it hardly disintegrates in water and is not reused at present. In addition, when discarded, polyolefins do not decompose in the natural environment, so they remain in the environment and cause environmental destruction.

[0003] In recent years, wax emulsions, resin emulsions,
Moisture proof paper has been used in which a water disintegrating moisture proofing agent such as latex or a mixture thereof is coated on a paper material.
For example, Japanese Unexamined Patent Publication No. 5-156208 discloses a moisture-proof paper coated with a moisture-proofing agent mainly composed of a wax-based emulsion containing a paraffin wax or the like as a dispersoid and a water-soluble resin such as polyvinyl alcohol. .
Japanese Patent Application Laid-Open No. 6-200998 discloses styrene
A moisture-proof paper coated with a moisture-proof agent containing an acrylic acid copolymer or the like and a wax emulsion is disclosed. Further, Japanese Patent Application Laid-Open No. 9-67795 discloses a moisture-proof paper coated with a moisture-proof agent containing a synthetic resin latex and a hydrocarbon oligomer as main components and further containing a filler such as mica and talc. I have. These moisture-proof papers have almost the same moisture-permeability as laminated moisture-proof papers, and since they use a water-disintegrating moisture-proofing agent, they are easily disintegrated in water and can be easily regenerated.

[0004]

However, these water disintegrating desiccants are blended with low molecular weight substances such as waxes and hydrocarbon oligomers in order to enhance the moisture proofing performance. Low molecular weight substances bleed out to the surface of the desiccant layer. Normally, PPC paper is packaged so that the moisture-proofing agent layer is on the inside. Therefore, when the low molecular weight substance bleeds out, the PPC paper directly in contact with the moisture-proofing paper.
The low molecular weight substance is transferred to the PC paper, and the coefficient of friction of the PPC paper is reduced. P with reduced friction coefficient
When PPC paper including PC paper (hereinafter, this PPC paper is also referred to as “degraded PPC paper”) is set in a copier, when a certain number of PPC papers above the degenerated PPC paper are to be fed, a There is a problem that a slip occurs between the PPC sheet and the PPC sheet in contact with the deteriorated PPC sheet, and a double feed occurs in which a plurality of PPC sheets above the deteriorated PPC sheet are fed at one time. .

The present invention has been made in view of the above problems, and can prevent the transfer of the low molecular weight substance in the desiccant layer to the PPC paper in contact with the PPC paper.
It is an object of the present invention to provide a moisture-proof paper that can prevent the friction coefficient of the paper from being reduced.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is directed to a water-disintegratable moisture-proof paper in which a moisture-proofing layer made of a water-disintegrating moisture-proofing agent is formed on a paper material. The desiccant has a bulk specific gravity of 0.8 g / cm ³ or more and 2.0 g / cm ³ or less and an average particle diameter of 0.1 g / cm ³ or less.
A moisture-proof paper comprising a filler having a thickness of not less than micrometer and not more than 60 micrometers (claim 1).

According to the present invention, a filler having a bulk specific gravity of 0.8 g / cm ^{3 to} 2.0 g / cm ³ and an average particle diameter of 0.1 to 60 μm is added to the desiccant. , A part of the filler protrudes from the desiccant layer and is a PP to be packaged.
Contact C paper. Therefore, the contact area between the base material of the desiccant layer and the PPC paper can be suppressed, and the transfer of the low molecular weight substance to the PPC paper can be prevented.

In order to increase the number of places where a part of the filler protrudes from the moisture-proof layer to sufficiently suppress the contact area between the base material of the moisture-proof layer and the PPC paper, the amount of the filler is calculated in terms of solid content. 0.
It is preferable that the content be 2% by weight or more and 50% by weight or less (claim 2).

In these inventions, if the shape of the filler is substantially spherical, a part of the filler can more effectively protrude from the moisture barrier layer. Specific examples of such a filler include resin beads (claim 4).

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partial sectional view of a moisture-proof paper 1 according to one embodiment of the present invention. This moisture-proof paper 1 is formed by applying a water-disintegrating moisture-proofing agent to a paper material 3.
The moisture-proofing agent layer 2 is formed by the solid content of the water-disintegrating moisture-proofing agent. The moisture-proof agent layer 2 enhances the moisture-permeability of the moisture-proof paper 1 and prevents moisture absorption of the packaged object such as PPC paper.

As the paper material 3, for example, high quality paper, medium quality paper, bleached kraft paper, unbleached kraft paper, unbleached unbleached kraft paper, liner paper, and paper tube base paper can be used. The weighing of the paper material 3 is not particularly limited.
It is appropriately selected and used from those of 0 g / m ² or more and 300 g / m ² according to the purpose of use.

The water disintegrating desiccant used for the desiccant layer 2 includes wax emulsion, resin emulsion,
Known materials such as latex and mixtures thereof are used. If necessary, a hydrocarbon oligomer, a surfactant, a dispersant, a stabilizer, a pigment, and the like may be blended in the desiccant.

The desiccant further has a bulk specific gravity of 0.8 g /
A filler 4 having a size of not less than cm ^{3 and not} more than 2.0 g / cm ³ is incorporated. Fillers 4 such as mica, talc, clay and calcium carbonate which are usually used have a bulk specific gravity of 2.5 g /
cm ³ and the bulk specific gravity of the liquid component of the desiccant (1.
0g / cm ³ ). When the filler 4 having a high specific gravity is used, the filler 4 is applied when the moisture proofing agent is applied.
Settles toward the paper material 3 side, and the filler 4 hardly protrudes from the moisture barrier layer 2. Therefore, when packaging PPC paper,
The contact area between the PC paper and the base material 5 of the moisture barrier layer 2 becomes large, and the transfer of the low molecular weight substance from the base material 5 to the PPC paper cannot be suppressed. In the moisture-proof paper 1 of the present embodiment, the filler 4 having a low specific gravity of 0.8 g / cm ³ or more and 2.0 g / cm ³ or less is used.
Hardly settle, and a part of the filler 4 effectively projects from the moisture-proof agent layer 2. Therefore, the contact area between the PPC paper and the base material 5 can be suppressed, and the transfer of the low molecular weight substance from the base material 5 to the PPC paper can be suppressed.

In the present invention, the bulk specific gravity of the filler 4 is set to 0.
8 g / cm ³ or more means that the bulk specific gravity is 0.8 g.
If the filler 4 is less than / cm ^3, the filler 4 floats in the desiccant and is difficult to be uniformly mixed at the time of stirring, which makes the coating operation difficult. Further, in the present invention, the bulk specific gravity of the filler 4 is set to 2.0 g / cm ³ or less because the bulk specific gravity is 2.
If the filler 4 exceeds 0 g / cm ³ , the filler 4 sinks in the desiccant and is difficult to be uniformly mixed at the time of stirring, which makes the application operation difficult. This is because the contact area between the PPC sheet and the base material 5 increases due to sedimentation. From these viewpoints, the bulk specific gravity of the filler 4 is 0.9 g / cm ³ or more and 1.5 or more.
g / cm ³ or less is more preferable.

The bulk specific gravity is 0.8 g / cm ³ or more and 2.0 g
Examples of the filler 4 having a density of / cm ³ or less include resin beads, glass bubbles, and shirasu balloon.
Among these fillers 4, resin beads having a bulk specific gravity substantially equal to the bulk specific gravity of the liquid component of the desiccant, and the filler 4 itself having excellent moisture impermeability are preferred. Preferred resin beads include acrylic beads, high density polyethylene beads, low density polyethylene beads, styrene beads, urethane beads and the like.

Although the shape of the filler 4 is not particularly limited,
Even when the same amount of the filler 4 is blended, a plate-like, scale-like,
A substantially spherical filler 4 is preferable to a linear filler or the like. Examples of the substantially spherical filler 4 include spherical resin beads.

The amount of the filler 4 is 0.2% in terms of solid content.
% By weight to 50% by weight, preferably 1% by weight to 5% by weight.
% By weight or less is particularly preferred. If the compounding amount is less than the above range, the portion where a part of the filler 4 protrudes from the moisture-proof layer 2 is reduced, and the contact area between the base material 5 of the moisture-proof layer 2 and the PPC paper is sufficiently suppressed. You may not be able to do it. Conversely, if the blending amount of the filler 4 exceeds the above range, the moisture impermeability of the moisture-proof paper 1 may be reduced.

The average particle diameter of the filler 4 used is:
It is necessary that the thickness be 0.1 μm or more and 60 μm or less, and particularly preferably 15 μm or more and 40 μm or less. If the average particle diameter is less than the above range, the protrusion height of a part of the filler 4 projecting from the moisture-proof layer 2 becomes small, and the contact area between the base material 5 of the moisture-proof layer 2 and the PPC paper is reduced. In some cases, it cannot be sufficiently suppressed. Conversely, if the average particle diameter exceeds the above range, the smoothness of the PPC paper may be impaired, and the moisture-permeability of the moisture-proof paper 1 may be reduced.

The average particle diameter is 100% arbitrarily extracted.
It is determined by calculating the average value of the particle diameters of the individual fillers 4. Here, the particle diameter is the diameter of the sphere in the case of the spherical filler 4. Non-spherical filler 4
In the case of (1), the diameter of the smallest circle among the circles including the projected image obtained by enlarging the filler 4 with a microscope is defined as the particle diameter.

The amount of the applied moisture-proofing agent is 1 g / m in terms of solid content.
^{2 to} 50 g / m ² or less, preferably 5 g / m ^{2 to} 30
g / m ² or less is particularly preferred. If the application amount is less than the above range, the PPC paper or the like as a packaged object may be likely to absorb moisture. Conversely, if the coating amount exceeds the above range, the moisture-proofing effect may reach a ceiling and the economy may become uneconomical even though the cost of the moisture-proofing agent increases.

Various known methods can be used for applying the moisture proofing agent to the paper material 3. For example, the moisture proofing agent may be applied using a kiss roll coater, bar coater, roll coater, blade coater, kiss coater or the like. In addition, as shown in FIG. 1, the application of the desiccant may be performed not only on one side of the paper material 3 but also on both sides.

[0023]

EXAMPLES The present invention will be described below with reference to examples, but it should be understood that the present invention should not be construed as being limited based on the description of the examples.

[Preparation of moisture-proof paper] [Example 1] An emulsion containing a styrene-butadiene copolymer as a dispersoid and a low-molecular-weight hydrocarbon oligomer was prepared. As a filler, an acrylic bead having a substantially spherical shape, a bulk specific gravity of 1.14 g / cm ³ , and an average particle diameter of 30 micrometers (trade name “LOVECOLOR 030 (30F) manufactured by Dainichi Seika Kogyo Co., Ltd.) )
Clear)) was added and stirred at 0.2% by weight in terms of solid content. This desiccant was applied to bleached kraft paper weighing 80 g per square meter using a kiss roll coater. The coating amount was 20 g / m ^{2 in} terms of solid content.
This was dried to obtain the moisture-proof paper of Example 1.

[Examples 2 to 4] The moisture-proof papers of Examples 2 to 4 were obtained in the same manner as in Example 1 except that the amount of the filler to be added was varied as shown in Table 1 below. .

[Examples 5 to 8] The type of filler to be added was acrylic beads having a substantially spherical shape, a bulk specific gravity of 1.2 g / cm ³ , and an average particle diameter of 15 micrometers (Sekisui Chemical Co., Ltd.) Product name “MBX-15”
The moisture-proof papers of Examples 5 to 8 were obtained in the same manner as in Example 1 except that the amount of addition was changed as shown in Table 1 below.

[Examples 9 to 12] The kind of the filler to be added was substantially spherical, and the bulk specific gravity was 0.94 g / cm.
^{In step 3} , high-density polyethylene beads having an average particle diameter of 25 micrometers (trade name "flow beads prototype" manufactured by Sumitomo Seika Co., Ltd.) were used, and the amount of addition was varied as shown in Table 2 below. Otherwise in the same manner as in Example 1, moisture-proof papers of Examples 9 to 12 were obtained.

[Examples 13 to 16] The type of the filler to be added was substantially spherical and the bulk specific gravity was 0.94 g / cm ^3.
And high-density polyethylene beads having an average particle diameter of 15 micrometers (trade name “Flow beads HE5023” manufactured by Sumitomo Seika Co., Ltd.).
The moisture-proof papers of Examples 13 to 16 were obtained in the same manner as in Example 1 except that the amount was changed as shown in Table 1.

Comparative Example A moisture-proof paper of Comparative Example was obtained in the same manner as in Example 1 except that no filler was added.

[Evaluation of Each Moisture-Proof Paper] The moisture-proof papers of these Examples and Comparative Examples were subjected to the following evaluations.

[Photographing of Surface of Moistureproofing Layer] Microscopic photographs of the surface of the moistureproofing layer of the moistureproof paper of Example 3 and Comparative Example were taken to observe the state of the surface. FIG. 2 shows a micrograph of the moisture-proof paper of Example 3, and FIG. 3 shows a micrograph of the moisture-proof paper of the comparative example. All photographs have a magnification of 200 times. As is clear from FIGS. 2 and 3, in the moisture-proof paper of Example 3 using a moisture-proofing agent containing a filler, a part of the filler protrudes from the moisture-proofing agent layer. On the other hand, the surface of the moisture-proof paper of the comparative example using the moisture-proofing agent containing no filler is flat.

[Measurement of Static Friction Coefficient]
Twenty sheets of C paper (A4 size neutral paper for high speed, manufactured by Kishu Paper Co., Ltd., trade name: “Fine PPC paper”) were placed thereon, and the moisture-proof paper was placed thereon such that the moisture-proof agent layer faced down.
Further, 2,000 sheets of PPC paper (about 8 kg) were stacked as a weight thereon. In this state, it was left in an oven at 50 degrees Celsius for 48 hours, and then cooled in a thermo-hygrostat for 4 hours. This experiment was performed twice for each of the examples and comparative examples, and two PPC papers were obtained, each of which was in direct contact with the moisture-proof layer.

The surfaces of the two PPC papers which were in contact with the desiccant layer were superimposed on each other and were subjected to JIS-P-814.
The static friction coefficient was measured in accordance with the horizontal method specified in 7.
The measurement results are shown in Tables 1 and 2 below. 4 and 5 show the relationship between the static friction coefficient and the filler ratio.
Is shown in

The PPC which is not in contact with the moisture-proof paper at all
When the static friction coefficient of the paper was measured at the same time, the static friction coefficient was 0.59.

[Moisture Permeability Test] The moisture permeability of each of the moisture-proof papers of Examples and Comparative Examples was measured based on Method B of JIS-Z-0208.
The measurements were taken with the moisture barrier layer as the outside. The measurement results are shown in Tables 1 and 2 below.

[0036]

[Table 1]

[0037]

[Table 2]

From Tables 1 and 2, it can be seen that the moisture permeability of the moisture-proof paper does not clearly change even when the filler is blended, and that the blending of the filler does not adversely affect the moisture-proof performance.

Further, in Tables 1 and 2, and FIGS. 4 and 5, the moisture-proof paper of each embodiment using a moisture-proofing agent containing a filler is a comparative example using a moisture-proofing agent containing no filler. The coefficient of friction of the wrapped PPC paper is higher than that of the moisture-proof paper. This is because, in the moisture-proof paper of each embodiment, a part of the filler protrudes from the moisture-proof layer and the contact area between the base material and the PPC paper is suppressed. Therefore, the transfer of the low molecular weight substance from the moisture-proof layer to the PPC paper is suppressed. Is suppressed, and as a result, a decrease in the static friction coefficient of the PPC paper is suppressed. As is clear from FIGS. 4 and 5, the effect of suppressing the decrease in the coefficient of friction of PPC paper is more remarkable when the filler ratio is higher and when the average particle diameter of the filler is larger. In particular, in the moisture-proof paper of Example 4 using the moisture-proofing agent containing 2% by weight of a filler having an average particle diameter of 30 micrometers, the static friction coefficient of the wrapped PPC paper is 0.59, which is the moisture-proofing property. It is comparable to the coefficient of friction of PPC paper that does not contact the paper at all.

Although the moisture-proof paper of the present invention has been described above by taking the case of wrapping PPC paper as an example, the moisture-proof paper having little transfer of low molecular weight substances to the packaged object is not limited to the packaging of PPC paper. It can be applied to various uses such as packaging of a resin plate such as an acrylic plate, packaging of a steel coil, packaging of a steel plate, packaging of paper winding, and material for a moisture-proof corrugated cardboard and a moisture-proof paper tube.

[0041]

As described above, according to the present invention,
It is possible to prevent the low molecular weight substance in the desiccant layer from being transferred to the package. Therefore, if the item to be packaged is, for example, PP
In the case of C paper, it is possible to prevent the friction coefficient of the PPC paper from being reduced, and to prevent double feeding during copying.

Further, according to the present invention, the filler does not float or sink in the desiccant, so that the work of stirring and applying the desiccant can be facilitated.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a moisture-proof paper according to an embodiment of the present invention.

FIG. 2 is a micrograph showing a moisture-proof layer of a moisture-proof paper according to an example of the present invention.

FIG. 3 is a micrograph showing a moisture barrier layer of a moisture barrier paper according to a comparative example of the present invention.

FIG. 4 is a graph showing a relationship between a filler ratio and a coefficient of static friction.

FIG. 5 is a graph showing a relationship between a filler ratio and a coefficient of static friction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Moisture-proof paper 2 ... Moisture-proof agent layer 3 ... Paper material 4 ... Filler 5 ... Base material

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) D21H 11/00-27/42

Claims (4)

(57) [Claims] 1. A water-disintegratable moisture-proof paper having a water-disintegrating moisture-proofing agent layer formed on a paper material, wherein the moisture-proofing agent has a bulk specific gravity of 0.8 g / cm ^3. Above 2.
0 g / cm ³ Ri der less, average grain diameter 0.1 microphone
Proof paper, characterized in that Der Ru filler 60 micrometers inclusive Rometa is blended. 2. The moisture-proof paper according to claim 1, wherein the amount of the filler is 0.2% by weight or more and 50% by weight or less in terms of solid content. The shape of claim 3, wherein said filler, moisture-proof paper according to claim 1 or 2 which is substantially spherical. Wherein said filler, moisture-proof paper according to any one of claims 1 to 3 is a resin bead.