JP2005023462A - Paper material for high-sunscreen container and packaging container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper material for high-sunscreen container and a packaging container made of the paper material. <P>SOLUTION: The paper material for high-sunscreen container and a packaging container made of the paper material are characterized by that active carbon as a sunscreen substance derived from natural materials such as vegetable matter is used rather than a fossil fuel-derived sunscreen substance such as carbon black, thus environmental problems are considered, and a sunscreen layer containing 0.02-2.0 g/m<SP>2</SP>active carbon is provided as an intermediate layer of paper laminated in three or more layers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a container paper material having a high light-shielding property used for a packaging container, particularly a food packaging container, and a packaging container using this paper material.
[0002]
[Prior art]
Paper has been widely used as a material for packaging containers such as cups and cartons.
When paper is used as a packaging container, light rays may penetrate the paper and affect the contents, particularly foods.
For example, when the contents are sake, green tea, yogurt, oils or fats, high-fat ice cream, etc., these are easily affected by light, causing deterioration of the pigment and quality, and significantly reducing the commercial value. Sometimes.
In order to prevent the deterioration of the contents as described above, it is necessary to suppress the light transmission of the paper used (hereinafter sometimes referred to as light shielding).
However, the wavelength causing the quality deterioration of the contents is not specified, and it is necessary to shield the wavelengths in the visible light region, the near ultraviolet region, and the near infrared region.
[0003]
In order to shield such areas, light is shielded by printing ink ink on the paper surface, pasting aluminum foil (hereinafter referred to as “aluminum foil”) on paper, or coloring some layers of paper. A paper having a property (hereinafter sometimes referred to as a light-shielding paper) is made.
Among these methods, in the case of light-shielding paper made by printing on the paper surface, printing is performed to shield light, and white printing is performed on the light-shielding printing layer in order to maintain whiteness. There is a drawback that production efficiency is poor.
In addition, in the case of light-shielding paper made by bonding aluminum foil to paper, a sufficient effect in light-shielding performance can be obtained, but there is no incineration suitability such as burning in the incinerator during incineration, which is one of the environmental problems It has become.
[0004]
The light-shielding paper made by coloring a part of the paper is, for example, unexposed pulp as disclosed in Japanese Utility Model Publication No. 59-103800, or the pulp is colored with a dye or a coloring pigment, or It is made by using together.
In the case of paper that is shaded by unbleached pulp, there is a problem that the pulp smell is slightly stronger than that of exposed pulp.
In the case of paper colored with a dye, depending on the contents, the dye may dissolve and the commercial value of the contents may be reduced.
Carbon black is disclosed in Japanese Patent Application Laid-Open No. 4-104143 and Japanese Patent Application Laid-Open No. 2001-11796 as color pigments used for light shielding paper.
[0005]
Conventionally, a sulfuric acid band has been often used for fixing carbon black. However, JP-A-4-104143 discloses a method of providing a light shielding layer with carbon black and a cationic dye. In the case of such light-shielding paper, a cationic dye is used for fixing carbon black, and when used as a food container, the cationic dye used for fixing may be attached to the contents. was there.
In order to solve this drawback, the present applicant has proposed a technique for fixing carbon black with a cationic amine-containing fixing agent to obtain a high light-shielding property according to Japanese Patent Application Laid-Open No. 2001-11796. Both neutral papermaking has the effect of providing a high degree of light shielding.
[0006]
By the way, in recent years, due to increasing awareness of global environmental issues, efforts have been made in various areas to reduce the use of fossil fuels such as oil and coal, and to reduce carbon dioxide emissions in order to prevent global warming. Yes. On the other hand, some are concerned about the depletion of energy resources due to the massive consumption of fossil fuels.
In view of the above situation, the applicant of the present invention uses not only a fossil fuel-derived light shielding material such as carbon black or synthetic dyes but also activated carbon derived from natural materials such as plant material as a light shielding material in order to reduce the amount of fossil fuel used as much as possible. Intensive research and development was conducted to develop the container paper material and packaging container used, and the present invention was completed.
[0007]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-11796 A structure in which carbon black is fixed with a cationic amine-containing fixing agent to provide high light shielding properties
[Problems to be solved by the invention]
The main object of the present invention is a container having high light-shielding properties, which has high light-shielding properties and contains activated carbon derived from natural materials such as plant material as a light-shielding material in an intermediate layer of paper material in consideration of environmental problems. The object is to provide a paper material and a packaging container using the paper material.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a container paper material having a high light shielding property according to claim 1.
Technology that the intermediate layer of paper laminated in three or more layers is made of a light shielding layer containing activated carbon derived from natural materials such as plant matter in the range of 0.02 to 2.0 g / m ² and has high light shielding properties. Take appropriate measures.
In the invention of claim 2,
Technical measures are taken that the activated carbon contained in the intermediate layer has an average particle size of 0.2 to 2.0 μm.
In invention of Claim 3, the technical means of using the said container paper material as a packaging container is taken.
[0010]
Thereby, light in a wavelength range of 250 to 850 nm is suppressed, and the container paper material considering environmental problems by using activated carbon derived from a natural material instead of a fossil fuel as a light shielding material, and a packaging container using the same Is obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the container paper material having high light shielding properties of the present invention will be described in detail.
The container paper material 1 is a paper material laminated in three or more layers, and includes a surface layer 2 made of a pulp layer, a back layer 4, and an intermediate layer 3 that is a light shielding layer containing activated carbon (see FIG. 1).
Accordingly, the surface layer 2 or the back layer 4 may be a single layer or a plurality of layers.
The number of the surface layer 2 and the back layer 4 is not necessarily the same.
Further, the light shielding layer 3 containing activated carbon may be a single layer or a plurality of layers.
[0012]
The activated carbon is made of a plant material such as wood, sawdust, charcoal, and coconut shell, that is, a natural material.
The activated carbon having an average particle size in the range of 0.2 to 2.0 μm can be preferably used, and more preferably 0.4 to 1.2 μm.
If it is smaller than 0.2 μm, gelation may occur when a dispersion is prepared.
On the other hand, when it exceeds 2.0 μm, it may be difficult to fix to the pulp fiber.
[0013]
In addition, activated carbon that is dispersed in water with a polysaccharide is preferably used.
As the polysaccharide, those derived from natural materials such as sodium carboxymethyl cellulose and starch can be used as well as activated carbon.
The addition amount of the activated carbon needs to be added so as to be in the range of 0.02 to 2.0 g / m ² .
If it is less than 0.02 g / m ² , sufficient light shielding properties cannot be obtained.
When added in excess of 2.0 g / m ² , the light shielding effect almost reaches saturation, and it is not necessary to increase the light shielding effect, resulting in an increase in cost and deterioration of the appearance of the product.
[0014]
Moreover, the addition amount of activated carbon has the preferable range of 0.03-1.2 g / m < ² >.
That is, as described above, the light shielding effect is obtained at 0.02 g / m ² , but the reliability of the light shielding effect is further increased at 0.03 g / m ² .
Next, whiteness can be kept high up to 1.2 g / m ² . Beyond this, the whiteness is slightly reduced.
[0015]
The pulp used in this embodiment is not particularly limited, but may include cellulosic natural pulp, such as wood pulp such as chemical pulp and mechanical pulp, non-wood pulp such as kenaf, bagasse, hemp and bamboo, These can be used alone or in combination of two or more.
[0016]
The activated carbon can be fixed to pulp fibers by using a cationic polymer or a sulfuric acid band. A cationic polymer such as a cationic polyacrylamide resin, a polyamide epichlorohydrin resin, a cationic amine-containing resin, a sulfuric acid band, or the like is appropriately selected and added to the above-described constituent materials for use.
In addition, various anionic, nonionic, cationic or amphoteric paper strength enhancers, sizing agents and the like conventionally used for the purpose of improving paper strength and imparting size performance are selected and used as necessary. be able to.
[0017]
For example, various paper strength enhancers such as polyacrylamide-based anionic, nonionic, cationic or amphoteric resins, polyamine polyamide and derivatives thereof, cationic and amphoteric starch can be used as the paper strength enhancer.
Examples of the sizing agent include various sizing agents such as rosin-based, alkyl ketene dimer-based, and alkenyl succinic anhydride-based.
[0018]
Furthermore, generally known fillers, for example, mineral fillers such as talc, kaolin, calcium carbonate and titanium dioxide can be appropriately selected and used. For the purpose of fixing these chemicals, inorganic compounds such as sulfuric acid bands can be used in appropriate combination.
In addition, as a papermaking additive, a pH adjuster, an antifoaming agent, a sticking agent, and the like can be used as necessary.
[0019]
In addition, starch, polyvinyl alcohol, polyacrylamide-based paper strength enhancers, and various surface sizing agents by coating methods such as size press coat, gate roll coat, calendar coat, blade coat, roll coat, air knife coat, and bar coat It is also possible to apply a pigment or the like.
In this embodiment, examples of the paper machine used for paperboard making include a circular net type, a short net type, a long net type, and a combination type.
[0020]
Moreover, it is preferable that the basic weight of the paper board of a paper material is the range of 100-600 g / m < ² > in this embodiment.
When the basis weight of the paperboard is less than 100 g / m ² , when the necessary amount of activated carbon is added to the intermediate layer, the black color of the intermediate layer is seen through the paper surface and the appearance is deteriorated.
If it exceeds 600 g / m ² , the productivity may be lowered due to a decrease in dehydrability or a decrease in drying efficiency.
More preferably, it is 200-500 g / m < ² >. If it is 200 g / m ² or more, the appearance is further improved, and if it is 500 g / m ² or less, the productivity can be further improved.
[0021]
The light-shielding paper material obtained from the constituent materials as described above is often printed and laminated in the next step.
For printing, gravure printing, offset printing, flexographic printing, and the like can be used.
As the printing ink, gravure ink, offset ink, flexographic ink, etc. suitable for each printing can be used.
Examples of the resin used for laminating include various resins such as polyethylene resin, polypropylene resin, polyamide resin, polyester resin, and ethylene vinyl alcohol copolymer resin, and they may be used alone or in a laminate thereof.
[0022]
Then, it is molded into a packaging container by a known appropriate method and used.
Examples of the form of the packaging container 5 include a carton type, a tray type, a box type, and a cylinder type in addition to the cup type illustrated in FIG. 2, for example. Of course, the shape is not particularly limited. is there.
Further, the packaged items stored in the container are often used for solid or liquid foods, but are not limited to foods as long as the contents are affected by light. The package may be a gas.
[0023]
【Example】
Examples The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
In the following, “%” and “parts” represent “% by weight” and “parts by weight”.
Hardwood bleached kraft pulp is labeled LBKP, softwood bleached kraft pulp is labeled NBKP, and hardwood unbleached kraft pulp is labeled LUKP.
Moreover, the addition amount of the activated carbon of each Example, pH of a papermaking raw material, and the set basic weight of shading paper were shown in FIG. 6, and each comparative example was shown in FIG.
[0024]
In addition, the measurement method of color fading which is an index of light transmittance and fixability in the following examples and comparative examples is as follows.
[Light transmittance]
Measurement was made at a wavelength of 250 nm to 850 nm at intervals of 50 nm with a spectrophotometer manufactured by JASCO Corporation. Since the absolute value of the light transmittance of the paper itself of the present invention is small and difficult to measure, the measurement was performed using the filter paper as a reference.
The light transmittance T of the paper is expressed by the following equation. No. of quantitative filter paper T = (ti / to) × 100 where 5C (trade name, manufactured by Toyo Roshi Kaisha, Ltd.) itself has the light transmittance as to and the light transmittance of the paper material itself as ti.
Here, when the average value of the light transmittance was 15% or less, it was determined that the light shielding property was good.
[0025]
[Color fading]
The sample is immersed in water or a 1% aqueous citric acid solution at 20 ° C. for 24 hours, and the sample is taken out, sandwiched between filter papers, and pressed at a press pressure of 5 kgf / cm ² for 4 hours. Then, it dried at 105 degreeC * 2 hours with the hot air circulation type dryer, and the color adhering to the filter paper was determined visually. The thing without coloring was set as (circle), and the thing in which coloring was recognized was set as x.
[0026]
[Example 1]
The pulp in which 50 parts of LBKP and 50 parts of NBKP were mixed was disintegrated with a pulper, and beaten with a beater until the stock concentration was 4% and the Canadian standard freeness (C.S.F) was 400 ml to obtain a pulp slurry.
Wet paper strength agent WS-570 (trade name, manufactured by Seiko PMC Co., Ltd.) 0.31 part, alkyl ketene dimer sizing agent AS-262 (trade name, manufactured by Seiko PMC Co., Ltd.) 0 .33 parts, 0.3 parts of copolymerized polyacrylamide type paper strength enhancer Hermide EX-370 (trade name, manufactured by Harima Chemicals Co., Ltd.), Hoffman modified polyacrylamide type paper strength enhancer Stargum KX-12 (trade name) (Manufactured by Seiko PMC Co., Ltd.) was added to 0.3 parts of pulp solids, and the pH was adjusted to 7.5 to obtain a paper raw material for the front and back layers.
[0027]
The papermaking raw material prepared in the same manner as the surface layer and the back layer is diluted to a stock concentration of 0.3%, and the activated carbon dispersion AC-2000 black (trade name, Daiichi Seika Kogyo Co., Ltd.) was added, followed by 1.5 parts of alkylamine-based fixing agent Daifix YK-50 (trade name, manufactured by Daiwa Chemical Industry Co., Ltd.). A papermaking material was used.
[0028]
These paper raw materials are made into a three-layer structure in the order of a surface layer, an intermediate layer, and a back layer using a circular net type paper machine so that the basis weight of the intermediate layer is 60 g / m ² , and the total basis weight is 300 g. A paper material of / m ² was obtained.
Thereby, the amount of activated carbon contained in the intermediate layer became 0.50 g / m ² .
The measurement results of the basis weight, thickness and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. The light shielding property was good, and there was no color fading.
[0029]
[Example 2]
0.6 parts of rosin-based sizing agent Perosa WS (trade name, manufactured by Modern Chemical Industry Co., Ltd.), polyacrylamide paper strength enhancer Stargum A-15 (trade name, 0.5 parts by Seiko PMC Co., Ltd. and 1.5 parts sulfuric acid band were added to the pulp solids to adjust the pH to 4.5, and used as the papermaking raw material for the front and back layers. The papermaking raw material prepared in the same manner as the surface layer and the back layer was diluted to a stock concentration of 0.3%, and the activated carbon dispersion AC-2000 black was added so that the activated carbon was 0.83 parts with respect to the pulp solid content. Then, paper was made in the same manner as in Example 1 except that 1.5 parts of an alkylamine-based fixing agent was added to obtain a papermaking raw material for the light-shielding layer (intermediate basis weight 60 g / m ² , overall basis weight 300 g / m ² ).
Thereby, the amount of activated carbon contained in the intermediate layer became 0.50 g / m ² .
The measurement results of the basis weight, thickness and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Also in this case, the light shielding property was good and there was no color fading.
[0030]
[Example 3]
Papermaking was carried out in the same manner as in Example 1 except that the activated carbon dispersion AC-2000 black was added so that the activated carbon was 0.05 parts with respect to the pulp solid content.
Here, the pH of the papermaking is 7.5, and the basis weight of the entire light shielding paper is 300 g / m ² .
As a result, the amount of activated carbon in the intermediate layer became 0.03 g / m ² .
The measurement results of the basis weight, thickness and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Also in this case, the light shielding property was good and there was no color fading.
[0031]
[Example 4]
Papermaking was performed in the same manner as in Example 1 except that the basis weight of the intermediate layer was 46 g / m ² and the total basis weight was 230 g / m ² . Here, the pH of the papermaking is 7.5.
As a result, the amount of activated carbon in the intermediate layer became 0.38 g / m ² .
The measurement results of the basis weight, thickness, and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Also in this case, the light shielding property was good and there was no color fading.
[0032]
[Example 5]
Paper making was performed in the same manner as in Example 2 except that the basis weight of the intermediate layer was 46 g / m ² and the total basis weight was 230 g / m ² . Here, the pH of the papermaking is 4.5.
As a result, the amount of activated carbon in the intermediate layer became 0.38 g / m ² .
The measurement results of the basis weight, thickness, and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Also in this case, the light shielding property was good and there was no color fading.
[0033]
[Example 6]
Example 1 except that the activated carbon dispersion AC-2000 black was added so that the activated carbon was 3.0 parts with respect to the pulp solid content, and 5.4 parts of the alkylamine-based fixing agent Dyfix YK-50 was added. Paper was made in the same way.
Here, the pH of the papermaking is 7.5, and the basis weight of the entire light shielding paper is 300 g / m ² .
As a result, the amount of activated carbon in the intermediate layer became 1.8 g / m ² .
The measurement results of the basis weight, thickness, and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Also in this case, the light shielding property was good and there was no color fading.
[0034]
[Comparative Example 1]
Activated carbon dispersion AC-2000 Black was added so that the activated carbon was 5.0 parts with respect to the pulp solid content, and 9.0 parts of alkylamine-based fixing agent Dyfix YK-50 was added. A paper was obtained.
Here, the pH of the papermaking is 7.5, and the basis weight of the entire light shielding paper is 300 g / m ² .
As a result, the amount of activated carbon in the intermediate layer became 3.0 g / m ² .
The measurement results of the basis weight, thickness and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Although there was no color fading and the light-shielding property was good, the light transmittance was the same as in Example 6, and the whiteness of the surface was lowered, which was not preferable in appearance.
[0035]
[Comparative Example 2]
The same as in Example 2 except that the activated carbon dispersion AC-2000 black was added so that the activated carbon was 5.0 parts with respect to the pulp solids, and 9.0 parts of the alkylamine-based fixing agent Dyfix YK-50 was added. A paper was obtained.
Here, the pH of the papermaking is 4.5, and the basis weight of the entire shading paper is 300 g / m ² .
As a result, the amount of activated carbon in the intermediate layer became 3.0 g / m ² .
The measurement results of the basis weight, thickness and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Although there was no color fading and the light-shielding property was good, the light transmittance was the same as in Example 6, and the whiteness of the surface was lowered, which was not preferable in appearance.
[0036]
[Comparative Example 3]
Paper was obtained in the same manner as in Example 1 except that the activated carbon dispersion AC-2000 black was added so that the activated carbon was 0.017 part with respect to the pulp solid content.
Here, the pH of the papermaking is 7.5, and the basis weight of the entire light shielding paper is 300 g / m ² .
As a result, the amount of activated carbon in the intermediate layer became 0.01 g / m ² .
The measurement results of the basis weight, thickness and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Although color fading did not occur, sufficient light shielding performance was not obtained.
[0037]
[Comparative Example 4]
20 parts of the cationic dye Kayacel Black CN-liq (trade name, manufactured by Nippon Kayaku Co., Ltd.) is added to the papermaking raw material prepared in the same manner as the surface layer and back layer of Example 1, and the paper for middle layer is added. Paper making was performed in the same manner as in Example 1 except that the raw material was used.
Here, the pH of the papermaking is 7.5, and the basis weight of the entire light shielding paper is 300 g / m ² .
The measurement results of the basis weight, thickness and density of this paper material are shown in the table of FIG. 3, and the measurement results of light transmittance and color fading are shown in the tables of FIGS. Although the light-shielding property was good, color fading of the dye occurred.
[0038]
【The invention's effect】
From the results of the above examples, a highly light-shielding paper material having high light-shielding properties in the wavelength range of 250 to 850 nm, having no contamination of the contents, and considering environmental issues can be obtained. It was.
And, using this highly light-shielding paper material, a packaging container of cup shape, carton shape, or other arbitrary shape was manufactured. Similarly, it has high light shielding property in the wavelength range of 250 to 850 nm, and the contents A packaging container that does not contaminate was obtained.
In addition, it was confirmed that the container paper material is suitable for food packaging containers that are easily affected by light, but can also be applied to other articles.
[Brief description of the drawings]
[Figure 1]
It is a fragmentary sectional view showing a container paper material typically.
[Figure 2]
It is a side view which shows the cup as an example of the packaging container.
[Fig. 3]
It is a table | surface which shows the basic weight, thickness, and density result of each Example and a comparative example.
FIG. 4 is a table showing the light transmittance results of each example and a comparative example.
FIG. 5 is a table showing color fading results of each example and a comparative example.
FIG. 6 is a table showing the amount of activated carbon added and the set basis weight of paper in each example.
FIG. 7 is a table showing the added amount of activated carbon and the set basis weight of paper in each comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Container paper material 2 Surface layer 3 Middle layer which is a light shielding layer 4 Back layer 5 Packaging container

Claims (3)

The intermediate layer of paper laminated in three or more layers consists of a light shielding layer containing activated carbon derived from natural materials in a range of 0.02 to 2.0 g / m ^2. Container paper material. The container paper material having high light-shielding properties according to claim 1, wherein the activated carbon contained in the intermediate layer has an average particle diameter of 0.2 to 2.0 µm. A packaging container using the container paper material according to claim 1.

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