JP7375736B2 - paper packaging - Google Patents

Description

The present invention relates to paper packaging.

Conventionally, there has been a demand for packages such as envelopes that have parts that are visible from the outside, such as transparent envelopes made of resin film, envelopes with resin film or glassine paper pasted on the visible part of paper envelopes, etc. (For example, see Patent Document 1).

Utility model registration No. 3153857

As described in Patent Document 1, when glassine paper is pasted on the window, the water resistance of the glassine paper is low, and when the envelope gets wet, water seeps through the glassine paper part, making it difficult to use the glassine paper, especially when visibility is required. There was a problem with parts getting wet.
In addition, although envelopes made of resin film or envelopes with resin film pasted on the windows have excellent water resistance, they require separate disposal, making it difficult to dispose of by incineration easily, making them environmentally friendly. From the viewpoint of load reduction, it is required to refrain from using it.
An object of the present invention is to provide a paper package that uses a paper base material, has excellent transparency and water resistance, and is suppressed from curling.

As a result of intensive studies, the present inventors formed a transparent portion by applying a transparent resin to a paper packaging body formed from a single sheet of paper, and It has been found that the above problems can be solved by setting the relationship between the Steckigt sizing degree of the part, the density of the paper base material, the amount of transparentizing resin applied, and the basis weight of the paper base material to a specific range. .
That is, the present invention relates to the following <1> to <8>.
<1> A paper packaging body formed from a sheet of paper and having at least one opening, the paper member having a transparent resin applied to at least a part of the paper base material, On at least one side of the package, a transparent resin is applied to 5% or more of the area, the Steckigt sizing degree of the area to which the transparent resin is applied is 120 seconds or more, and the density of the paper base material is 0. .95 g/cm ³ or less, and the amount of the transparent resin applied is 1.3 times or less the basis weight of the paper base material.
<2> The paper packaging according to <1>, wherein the opacity of the portion to which the transparent resin is applied is 60% or less.
<3> The paper package according to <1> or <2>, wherein the amount of the transparent resin applied to the paper base material is 12 g/m ² or more and 150 g/m ² or less.
<4> The paper package according to any one of <1> to <3>, wherein the paper base material has a basis weight of 20 g/m ² or more and 150 g/m ² or less.
<5> The method according to any one of <1> to <4>, wherein the amount of the transparentizing resin applied to the paper base material is 0.2 times or more and 1.5 times or less the basis weight of the paper base material. Paper packaging.
<6> The paper packaging according to any one of <1> to <5>, wherein the portion to which the transparent resin is applied has a tensile strength of 3.5 kN/m or more.
<7> Any one of <1> to <6>, wherein the tensile strength of the part to which the transparent resin is applied is 1.3 times or more the tensile strength of the part to which the transparent resin is not applied. Paper packaging described in .
<8> The paper package according to any one of <1> to <7>, wherein the paper package is an envelope.

According to the present invention, it is possible to provide a paper package that uses a paper base material, has excellent transparency and water resistance, and is suppressed from curling.

FIG. 1 is a basic configuration diagram of a paper package.

[Paper packaging]
The paper packaging body of the present invention is a paper packaging body formed from a single sheet of paper member and having at least one opening, and in which at least a portion of the paper base material is provided with a transparent resin. 5% or more of the area of the paper packaging is coated with a transparent resin, and the Steckigt sizing degree of the portion coated with the transparent resin is 120 seconds or more, and the paper packaging is The density of the base material is 0.95 g/cm ³ or less, and the amount of the transparent resin applied is 1.3 times or less the basis weight of the paper base material.
The paper package of the present invention uses a paper base material and has excellent transparency and water resistance.
The reason why the above effects can be obtained is thought to be as follows.
In conventional paper packages such as envelopes that have an opening and glassine paper pasted to the opening, the glassine paper part has low water resistance, and water easily enters from the pasted part. Therefore, there was a problem with water resistance.
Since the paper package of the present invention is made of a single sheet of paper, unlike the case where glassine paper is used, the paper package does not have a pasting part in the window, which contributes to improved water resistance. .
Furthermore, a transparent part (window part) is created by applying a transparent resin, and by setting the Steckigt sizing degree of the part to which the transparent resin is applied to a specific range, it has particularly excellent water resistance. I discovered that.
Furthermore, it has been found that by applying a transparent resin to a paper base material, the tensile strength of the portion to which the transparent resin is applied is improved. It is thought that this improves the tensile strength of the entire paper package to which the transparent resin has been applied.
Furthermore, by setting the density of the paper base material and the transparent resin within a specific range relative to the basis weight of the paper base material, when applying the transparent resin, the paper base material penetrates into the paper base material appropriately. However, as a result, it is thought that the occurrence of curling due to the application of the transparent resin is suppressed.
The present invention will be explained in more detail below.

In the present invention, the paper package is not particularly limited as long as it is formed from a single sheet of paper and has at least one opening, and may be, for example, a paper bag, an envelope, a clear holder, a paper clip, etc. Illustrated. Among these, paper bags and envelopes are preferred, and envelopes are more preferred. Paper bags and envelopes may have gussets or no gussets.
Note that having at least one opening means that the paper package accommodates an article inside the paper package.
FIG. 1 is a basic configuration diagram of a paper package.
The paper package of the present invention will be explained using FIG. 1. Although FIG. 1 shows an envelope as a paper package, the present invention is not limited to this.
A paper package 10, which is an envelope shown in FIG. 1, is formed from a single sheet of paper member S, and has one opening 12.
Note that "formed from one sheet of paper" means that it is not formed from two or more sheets of paper. Therefore, for example, there may be an embodiment in which an adhesive member is provided for adhering paper members, or if the paper package is an envelope, a ball string is provided to fasten the flap part so that it can be opened and closed repeatedly. This includes an embodiment in which the paper bag is attached with a handle, and an embodiment in which a handle is attached to the paper bag.

In the present invention, the paper member S has a transparent resin applied to at least a portion of the paper base material. In FIG. 1, a portion to which a transparent resin is applied is illustrated as a transparent portion 13. Further, on at least one surface of the paper package, a transparent resin is applied to 5% or more of the area.
The transparent resin may be applied to at least a portion of the paper base material, but in order to visually recognize the contents, the transparent resin is applied to at least 5% or more of the area of one side. Note that the area to which the transparent resin is applied is not particularly limited, and may be applied to substantially the entire surface. Further, it is sufficient that the transparent resin is applied to at least one surface, and for example, the transparent resin may be applied to two or more surfaces. As will be described later, from the viewpoint of improving tensile strength, it is preferable that the area to which the transparent resin is applied is large, for example, on at least one side, preferably 10% or more, more preferably 20% or more, and even more preferably is 30% or more.
In FIG. 1, a transparent resin is applied to a window portion for viewing the contents, and a transparent portion 13 is formed.

The transparent resin may be applied to the inner surface or the outer surface of the paper package, but from the viewpoint of reducing uneven coating of the transparent resin, it is preferably applied to the inner surface.

In the paper package of the present invention, the Steckigt sizing degree of the portion to which the transparent resin is applied is 120 seconds or more from the viewpoint of obtaining sufficient water resistance.
The Steckigt sizing degree is preferably 130 seconds or more, more preferably 140 seconds or more, even more preferably 200 seconds or more, and from the viewpoint of ease of manufacture, preferably 1000 seconds or less, more preferably 800 seconds or less, More preferably, it is 600 seconds or less.
Steckigt size degree is measured according to JIS P 8122:2004.
The method for adjusting the Steckcht sizing degree within the above range is not particularly limited, but the desired Steckcht sizing degree can be adjusted by adjusting the type and thickness of the paper base material, the type of transparent resin, the amount of coating, etc. be able to. In particular, it is preferable to adjust the degree of Steckigt sizing to a desired degree by adjusting the amount of the transparent resin applied.

In the paper packaging of the present invention, the opacity of the portion to which the transparent resin is applied is preferably 60% or less, more preferably 55% or less, still more preferably 50% or less, from the viewpoint of improving visibility. And, from the viewpoint of ease of manufacture, it is preferably 3% or more, more preferably 4% or more, and even more preferably 5% or more.
Opacity is measured by the opacity test method specified in JIS P 8149:2000.

In the paper packaging of the present invention, the tensile strength of the portion to which the transparent resin is applied is preferably 3.5 kN/m or more, more preferably It is 4.5 kN/m or more, more preferably 5.5 kN/m or more.
The tensile strength is measured by the tensile strength testing method specified in JIS P 8113:2006.
In addition, since the tensile strength is also improved by applying the transparent resin, it is preferable from the viewpoint of improving the tensile strength that the area to which the transparent resin is applied is wide.
Further, the tensile strength differs in the longitudinal and transverse directions of the fiber orientation, but it is preferable that the tensile strength is within the above range at least in the longitudinal direction, and it is preferable that the tensile strength be within the above range in both the longitudinal and transverse directions. More preferred. Note that the longitudinal direction is the papermaking direction (MD), and the transverse direction is the direction perpendicular to the papermaking direction (CD), which is the same as the fiber orientation direction.

In addition, in the present invention, the tensile strength of the part to which the transparent resin is applied (the transparent part) is 1.3 times or more the tensile strength of the part to which the transparent resin is not applied (the non-transparent part). It is preferable that there be. More preferably, it is 1.4 times or more, still more preferably 1.6 times or more, even more preferably 2.0 times or more. The upper limit is not particularly limited, but from the viewpoint of ease of manufacture, it is 4.0 times or less.

The paper package of the present invention may be partially printed, and preferably has printability. A pattern or colored paint may be applied to the inner surface of the paper package so that the contents cannot be seen through, and a pattern or colored paint may be applied to the outside of the paper package to add design or to indicate the contents. Printing may be added. Specifically, words such as "confidential" and "confidential" indicating the contents may be added, the name of the manufacturer, a bar code, etc. may be printed, and a postal code frame may also be printed. Moreover, in order to enhance the design, patterns or designs may be printed, and there is no particular limitation.
Any printing method may be applied to the printing process, and examples include flexographic printing, inkjet printing, gravure printing, offset printing, gravure offset printing, and silk screen printing.

The paper base material and transparent resin used in the paper packaging of the present invention will be described below.
<Paper base material>
The paper base material used in the paper packaging of the present invention is preferably a commonly used paper containing plant-derived pulp as the main component, and should be paper containing wood pulp or non-wood pulp as the main component. is more preferable. Further, it is preferable that the paper is mainly composed of pulp that is easily dispersed in water by mechanical disintegration.
Specific examples include bleached or unbleached kraft paper, high-quality paper, paperboard, liner paper, coated paper, single-glazed paper, glassine paper, graphane paper, etc. Among these, bleached or unbleached kraft paper, high-quality Paper and glossy paper are preferable, and single-glazed paper is more preferable from the viewpoint of printability and imparting a transparent resin. In this case, it is preferable that the glossy surface of the glossy paper is the outer surface and the inner surface is coated with a transparent resin.
By using a paper base material, the paper package of the present invention has excellent environmental load reduction, recyclability, and ease of disposal.

In addition to the internal sizing agent, other known internal additives may be added to the paper base material. Other internal additives include fillers such as titanium dioxide, kaolin, talc, and calcium carbonate, dry paper strength enhancers, wet paper strength enhancers, retention improvers, pH adjusters, drainage improvers, water resistance agents, Examples include softeners, antistatic agents, antifoaming agents, slime control agents, dyes, and pigments.
The internally added sizing agent is preferably a rosin-based sizing agent or a reactive sizing agent, and among the reactive sizing agents, an alkyl ketene dimer-based sizing agent and an alkenyl succinic anhydride-based sizing agent are more preferable. In addition, among paper strength enhancers, resins such as glyoxal, urea formaldehyde resin, melamine formaldehyde resin, polyamide urea formaldehyde resin, ketone resin, polyamide epichlorohydrin resin, polyamide polyamine epichlorohydrin resin, glycerol polyglycidyl ether resin, and polyethylene imine resin are used. Preferably used. These internal additives may be used alone or in combination of two or more.

In the paper making process for paper base materials, a known wet paper machine (for example, a Fourdrinier paper machine, a gap former paper machine, a cylinder paper machine, a short wire paper machine, etc.) may be selected and used as appropriate. can do. It is preferable that the paper layer formed by the paper machine is conveyed using felt and dried using a dryer, for example. A multi-stage cylinder dryer may be used as a pre-dryer before drying.

Furthermore, the paper base material obtained as described above may be subjected to surface treatment using a calendar to make the thickness and profile uniform. For the calendering process, a known calendering machine can be appropriately selected and used.

(Basic weight)
The basis weight of the paper base material is not particularly limited, but is preferably 20g/20g/kg from the viewpoint of improving water resistance by achieving a desired Steckigt sizing degree, and from the viewpoint of obtaining a paper package with excellent shape stability and strength. m ² or more, more preferably 25 g/m ² or more, still more preferably 30 g/m ² or more, and preferably 150 g from the viewpoint of economic efficiency, reducing environmental impact, and obtaining a paper packaging with excellent transparency. /m ² or less, more preferably 120 g/m ² or less, even more preferably 100 g/m ² or less.
The basis weight of the paper base material is measured in accordance with JIS P 8124:2011.

(paper thickness)
The thickness of the paper base material (paper thickness) is preferably 20 μm or more, more preferably 35 μm from the viewpoint of obtaining shape stability of the paper package, sufficient strength, and obtaining a transparent part with excellent transparency. Above, it is more preferably 50 μm or more, and preferably 200 μm or less, more preferably 160 μm or less, and even more preferably 120 μm or less.
The thickness of the paper base material (paper thickness) is measured in accordance with JIS P 8118:2014.

(density)
The density of the paper base material is 0.95 g/cm ³ or less, preferably 0.90 g/cm ³ or less, more preferably 0.85 g from the viewpoint of suppressing curling when the transparent resin is applied. /cm ³ or less, and from the viewpoint of obtaining shape stability and sufficient strength of the paper package, preferably 0.50 g/cm ³ or more, more preferably 0.60 g/cm ³ or more, even more preferably is 0.65 g/cm ³ or more.
It is preferable that the density of the paper base material is low because the transparent resin easily penetrates into the paper base material, and as a result, the paper base material and the transparent resin become integrated, thereby suppressing the occurrence of curling. On the other hand, when the paper base material has a high density, the transparent resin has difficulty penetrating into the paper base material, and tends to be strongly influenced by curling of either the paper base material or the transparent resin. In particular, when a UV-curable transparent resin is used as the transparent resin, the volume tends to decrease due to UV curing, and by setting the density of the paper base material within the above range, curling can be suppressed. It is preferable because
Note that the density of the paper base material is calculated based on JIS P 8118:2014 from the basis weight and paper thickness of the paper base material determined as described above.

<Transparent resin>
In the paper member constituting the paper package of the present invention, a transparent resin is applied to at least a portion of the paper base material.
Examples of the transparent resin include UV-curable transparent resin, rosin-based water-based transparent resin, petroleum-based hydrocarbon transparent resin, polyester-based transparent resin, urethane-based transparent resin, nitrocellulose-based transparent resin, etc. It can be suitably used.
These resins may be used alone or in combination of two or more.

The UV curable transparent resin (sometimes referred to as "UV varnish") is an acrylic transparent resin containing a (meth)acrylate monomer and a photopolymerization initiator. When applied to a paper base material, the UV curable transparent resin has the effect of reducing the opacity of the paper base material. Furthermore, when irradiated with ultraviolet rays, the photopolymerization initiator decomposes and the (meth)acrylate monomer polymerizes, thereby having the effect of curing the applied portion.
Examples of (meth)acrylate monomers include (meth)acrylate monomers, oligomers or prepolymers such as (meth)acrylate, and reactive diluents. Specific examples of these include ethyl ( Monofunctional monomers such as meth)acrylate, ethylhexyl(meth)acrylate as well as polyfunctional monomers such as polymethylolpropane tri(meth)acrylate, hexanediol(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, etc. ) acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, etc. are preferably used. These acrylate monomers may be used alone or in combination of two or more. Further, other monomers may be used together with the (meth)acrylate monomer, and examples of the other monomers include styrene, methylstyrene, N-vinylpyrrolidone, and the like.
As the photopolymerization initiator, acetophenones such as dichloroacetophenone and trichloroacetophenone, benzophenone, Michler's ketone, benzyl, benzoin, benzoin alkyl ether, benzyl dimethyl ketal, tetramethylthiuram monosulfide, thioxanthone, azo compound, etc. are preferably used. Ru. These photopolymerization initiators may be used alone or in combination of two or more.

As the UV curable transparent resin, for example, "Cybinol I can do it.
When curing the UV-curable transparent resin with ultraviolet light, a known light source such as a high-pressure mercury lamp, metal halide lamp, xenon lamp, or electrodeless discharge lamp is used, and the cumulative amount of light is, for example, 500 to 1,000 mJ/cm. ² and harden it.

The rosin-based aqueous transparent resin is a composition containing water and an emulsion of a rosin-based resin such as a natural rosin-based resin. When applied to a paper base material, the rosin-based water-based transparentizing resin has the effect of reducing the opacity of the paper base material. Further, the composition mixed with a thermosetting resin also has the effect of curing the applied portion by heating. Furthermore, since the composition is aqueous, it is also preferable in that the paper base material can be easily recycled.
As the rosin-based water-based transparent resin, for example, "Unit No. 10N Winter (product name)" and "Ecolos Isei AC-130N (product name)", both manufactured by Nikko Chemical Co., Ltd., can be suitably used. can.
When a thermosetting resin is mixed with a rosin-based aqueous transparent resin, a mixture of a modified epoxy resin and a solvent can be used as a modifier. More specifically, "Modifier M-14 (trade name)", "Modifier HS (trade name)", both manufactured by Nikko Chemical Co., Ltd., can be suitably used. Further, in order to adjust the viscosity, a diluting solvent may be added to a rosin-based aqueous transparent resin. The type of diluent solvent is not particularly limited, but a solvent with high affinity for water, such as propylene glycol monomethyl ether, can be suitably used.

Petroleum-based hydrocarbon transparent resins include alicyclic saturated hydrocarbons such as 1,4-bis(hydroxymethyl)cyclohexane and 2,2'-di(4-hydroxyphenyl)propane, and aromatic unsaturated hydrocarbons. Resins obtained and resins having various substituents such as amino groups, hydroxyl groups, vinyl groups, nitro groups, and carbonyl groups are preferably used. In addition, petroleum-based hydrocarbon resins include saturated hydrocarbons such as paraffin wax and isoparaffin, rapeseed oil, soybean oil, animal and vegetable oils and fats such as beef tallow hydrogenated fatty acids, stearic acid, phthalic anhydride, tetrahydrophthalic anhydride, isophthalic acid, terephthalic acid, and A combination of one or more saturated or unsaturated fatty acids such as mellitic acid and pyromellitic acid can also be used.
As the polyester-based transparent resin, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene copolymers such as ethylene-acrylic acid copolymers, etc. are preferably used.
The urethane-based transparent resin is obtained from the reaction of a polyisocyanate compound and an active hydrogen-containing compound, and is a polymer compound containing urethane bonds and urea bonds. Polyisocyanate compounds for producing polyurethane resins include aromatic polyisocyanates such as tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate, aliphatic and alicyclic polyisocyanates such as isophorone diisocyanate, and hexamethylene diisocyanate. etc. are preferably used.

In the present invention, among the transparent resins, it is preferable to use a rosin-based aqueous transparent resin and a UV-curable transparent resin, and it is more preferable to use a UV-curable transparent resin.
The reason why it is preferable to use a UV-curable transparent resin is that when a water-based transparent resin is applied to a paper base material, there is a step of drying it with hot air, which causes the moisture contained in the paper to evaporate and damage the paper base. This is because the material may curl. UV-curable transparent resins are preferable because there is no risk of moisture volatilization and the occurrence of curls is suppressed.
In addition, the reason why it is preferable to use acrylic transparent resin is that it has a high degree of transparency compared to other transparent resins, can exhibit transparency with a relatively small amount of coating, and has excellent durability, weather resistance, This is because it is comprehensively superior in terms of strength, workability, etc.
In addition, it is preferable to adjust the type of transparent resin, the applied amount, etc. as appropriate so that the above-mentioned opacity can be achieved by applying the transparent resin to the paper base material.

The amount of the transparent resin applied to the paper base material is preferably 12 g/m ² or more, more preferably 15 g/m ² or more, from the viewpoint of improving transparency and water resistance, and suppressing the occurrence of curling. More preferably, it is 25 g/m ² or more, even more preferably 50 g/m ² or more, and from the viewpoint of economic efficiency, it is preferably 150 g/m ² or less, more preferably 120 g/m ² or less.

The amount of the transparentizing resin applied to the paper base material is preferably 1.3 times or less the basis weight of the paper base material, from the viewpoint of improving transparency and water resistance, and suppressing the occurrence of curling. It is 1.2 times or less, more preferably 1.1 times or less, still more preferably 1.0 times or less, and preferably 0.2 times or more the basis weight of the paper base material, more preferably 0. It is 3 times or more, more preferably 0.5 times or more, even more preferably 0.8 times or more.
It is preferable that the amount of the transparent resin applied to the paper base material is 1.3 times or less the basis weight of the paper base material, since curling caused by the application of the transparent resin is suppressed.

The difference between the thickness of the paper base material to which the transparent resin has not been applied, that is, the thickness of the paper base itself, and the thickness of the paper base material to which the transparent resin has been applied, that is, the thickness of the transparent part ( The difference in thickness of the paper base material before and after applying the transparent resin is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6 μm or less, even more preferably 4 μm or less, and the transparency and water resistance are From the viewpoint of imparting properties, the thickness is preferably 0.5 μm or more, more preferably 1 μm or more.
It is preferable that the difference in thickness between the paper base material before and after applying the transparent resin is 10 μm or less, since curling caused by applying the transparent resin is suppressed.
When the transparent resin penetrates into the paper base material, the difference in the thickness of the paper base material before and after applying the transparent resin tends to become smaller. It is possible to reduce the difference in the thickness of paper base materials. In addition, if the amount of transparentizing resin applied is too large, the difference in the thickness of the paper base material before and after applying the transparentizing resin tends to become large, so the amount of applying the transparentizing resin to the paper base material is adjusted. By doing so, the difference in thickness can be reduced.

The method of applying the transparent resin is not particularly limited, and a method of impregnating only the necessary areas, and various printing methods (for example, flexo printing, inkjet printing, gravure printing, offset printing, gravure offset printing, silk screen printing) are used. do it.
Moreover, when the transparent resin is a UV-curable transparent resin, it may be cured by irradiating ultraviolet rays after being applied to the paper base material.

In the present invention, it is preferable that the paper base material to which the transparentizing resin is applied is inhibited from curling. When curling occurs, stress is generated when the paper package is made, which may cause wrinkles or tears.
As mentioned above, ways to suppress the problem of curling include controlling the density of the paper base material, the amount of transparent resin applied to the paper base material, and the difference in paper thickness before and after applying the transparent resin. This is exemplified.

EXAMPLES The features of the present invention will be explained in more detail below with reference to Examples and Comparative Examples. The materials, usage amounts, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

The paper base material, type of transparent resin, UV irradiation device, etc. used in Examples and Comparative Examples are as follows. Note that the basis weight and paper thickness are as shown in Table 1.
<Paper base material>
A: "Bamboo Pure White" manufactured by Chuetsu Pulp Industry Co., Ltd.
B: Manufactured by Oji Materia Co., Ltd., "Byakuya"
C: Manufactured by Oji Materia Co., Ltd., "OK Blizzard"
D: “Glasine” manufactured by Oji F-Tex Co., Ltd.

<Transparent resin>
Manufactured by Auto Kagaku Kogyo Co., Ltd., "UVF-102A-2", acrylic ultraviolet curing resin <UV irradiation device>
“Eye Grandage ECS-301G1” manufactured by Eye Graphics Co., Ltd.

Example 1
After applying a transparent resin at 15 g/m ² to approximately one surface of the paper base material shown in Table 1 using flexo printing, a UV irradiation device (manufactured by Eye Graphics Co., Ltd., Eye Grandage ECS-301G1) was applied. It was cured by irradiating ultraviolet rays at an integrated light amount of 50 mJ/cm ² and an illumination intensity of 100 mW/cm ² . In addition, when the paper base material was single-gloss paper, the transparent resin was applied to the rougher side (opposite the glossy side) of the single-gloss paper so that this became the inside (back side).
The resulting paper member was evaluated for Steckigt sizing, opacity, tensile strength, and curling properties of the transparent resin-applied portion.
The results are shown in Table 1 below.

<Measurement method>
The basis weight and paper thickness of the paper base material used, as well as the opacity, Steckigt sizing degree, tensile strength, and curling property of the transparent resin-applied portion of the obtained paper member were measured.
[Stekicht size degree]
Steckigt size degree was measured according to JIS P 8122:2004. Note that the measurement was performed from the front surface with the side to which the transparent resin was applied as the back surface.

[Basic weight]
The basis weight (g/m ² ) of the paper base material was measured according to JIS P 8124:2011. In addition, if the sample size necessary for the measurement described in JIS P 8118:2014 cannot be obtained, the measurement is performed using the sample size that can be collected.

[Paper thickness]
The thickness of the paper base material and the portion of the paper member to which the transparent resin is applied was measured in accordance with JIS P 8118:2014.

〔density〕
The density of the paper base material was calculated from the basis weight and paper thickness in accordance with JIS P 8118:2014.

[Opacity]
The opacity was measured by the opacity test method specified in JIS P 8149:2000. Moreover, the opacity was measured from the front side with the side to which the transparent resin was applied as the back side.

[Tensile strength]
The tensile strength was measured according to JIS P 8113:2006 using Autograph, RTC-1250A manufactured by Shimadzu Corporation. In Examples 1 to 11 and Comparative Examples 2, 7, and 8, the tensile strength at the transparent resin application area was measured. On the other hand, in Comparative Examples 1 and 3 to 6, the tensile strength of the uncoated area was measured. In addition, in the table, "vertical" means the orientation direction of the fibers, and "horizontal" means the direction perpendicular to the longitudinal direction. The fiber orientation was measured using an orientation measuring machine (SST-2500, manufactured by Nomura Shoji Co., Ltd.). Furthermore, the above-mentioned fiber orientation could be measured also in the portion to which the transparent resin was applied.

[Curling]
Prepare an A4 size paper member or paper base material obtained by coating a transparent resin according to the procedure of the example, and store the paper member or paper base material in an environment of 23°C ± 5°C and 50% ± 10%. The paper member was placed flat on a horizontal hard surface, and the degree to which the apex of the paper member was lifted from the hard surface was measured at all four locations, the average value was calculated, and curl evaluation was performed using the following criteria. .
Note that "good curl resistance" means that no curling is observed, that is, the curling is suppressed by the addition of the transparent resin.
A: Lifting of 0.0 mm or more and less than 1.0 mm was observed.
B: Lifting of 1.0 mm or more and less than 3.0 mm was observed.
C: Lifting of 3.0 mm or more was observed.

Examples 2 to 11, Comparative Examples 1 to 8
Examples 2 to 11 and Comparative Examples 1 to 8 were prepared in the same manner as in Example 1, except that the type of paper base material used in Example 1, the amount of transparent resin applied, etc. were changed as shown in Table 1. A paper member was produced and evaluated. For Comparative Examples 1 and 3 to 6, the Steckigt sizing degree and opacity were measured on the portions to which no resin was applied. In addition, in Comparative Example 7, the paper base material was calendered in advance to reduce the thickness of the paper base material and improve its density, and then the transparent resin was applied. The results are shown in Table 1.

In Examples 1 to 11, paper base materials with a Steckigt sizing degree within the range of the present invention (120 seconds or more) and excellent transparency were obtained. On the other hand, in Comparative Examples 1 and 3 to 5, in which no transparent resin was applied, sufficient transparency could not be obtained. Further, in Comparative Example 6 using glassine paper, the Steckigt sizing degree was 3 seconds, which was not within the range of the present invention (120 seconds or more), and the water resistance was poor.
Furthermore, when the amount of the transparentizing resin applied was small, as shown in Comparative Example 2, sufficient transparency could not be obtained. Further, the Steckigt sizing degree was also less than 120 seconds (101 seconds), which was not within the scope of the present invention, and a decrease in water resistance was observed.
It was also found that the tensile strength of all the parts to which the transparent resin was applied was improved compared to the parts to which the transparent resin was not applied.
Furthermore, in Examples 1 to 11, the amount of the transparentizing resin applied to the paper base material was 1.3 times or less than the basis weight of the paper base material, and the density of the paper base material was 0.95 g/cm ³ or less. It was found that the occurrence of curling after coating the transparent resin on the paper base material was suppressed, and the curling resistance was good. This is presumably because the lower the density of the paper base material, the more the transparent resin penetrates into the inside of the paper base material and becomes integrated, thereby suppressing the occurrence of curling. Furthermore, it is presumed that because the amount of transparent resin applied was appropriate, the occurrence of curling was suppressed. If the curl resistance is poor, wrinkles, tears, etc. will occur after processing as a paper package. On the other hand, in Comparative Example 7, the density exceeded 0.95 g/cm ³ and curling occurred due to the use of a high-density base material, resulting in poor curl resistance. Furthermore, in Comparative Example 8, the amount of the transparent resin applied was more than 1.3 times the basis weight of the paper base material, and because the amount of the transparent resin applied was large, curling occurred and the curling properties were poor. It was something.

The paper package of the present invention uses a paper base material, has excellent transparency and water resistance, and suppresses curling. The present invention is expected to be applied to various packages in which visible parts made of plastic resin films have conventionally been used.

S: Paper member 10: Paper packaging 12: Opening 13: Transparent part

Claims (8)

A paper packaging body formed from a single sheet of paper member and having at least one opening,
The paper member has a transparent resin applied to at least a part of the paper base material,
The transparent resin is a UV curable transparent resin,
A transparent resin is applied to at least 5% of the area of at least one surface of the paper package,
The Steckigt sizing degree of the part to which the transparent resin has been applied is 120 seconds or more,
The density of the paper base material is 0.95 g/cm ³ or less,
The amount of the transparentizing resin applied is 1.3 times or less the basis weight of the paper base material,
Paper packaging. The paper packaging according to claim 1, wherein the opacity of the portion to which the transparent resin is applied is 60% or less. The paper packaging body according to claim 1 or 2, wherein the amount of the transparent resin applied to the paper base material is 12 g/m ² or more and 150 g/m ² or less. The paper package according to any one of claims 1 to 3, wherein the paper base material has a basis weight of 20 g/m ² or more and 150 g/m ² or less. The paper package according to any one of claims 1 to 4, wherein the amount of the transparent resin applied to the paper base material is 0.2 times or more and 1.3 times or less the basis weight of the paper base material. The paper package according to any one of claims 1 to 5, wherein the portion to which the transparent resin is applied has a tensile strength of 3.5 kN/m or more. The paper product according to any one of claims 1 to 6, wherein the tensile strength of the part to which the transparentizing resin is applied is 1.3 times or more the tensile strength of the part to which the transparentizing resin is not applied. packaging. The paper package according to any one of claims 1 to 7, wherein the paper package is an envelope.