JP2024044540A - Functional composition, functional paper material using the same, and functional cardboard - Google Patents

Abstract

To enhance the safety for human use of paper materials that can remove reductive sulfur compounds and exhibit antiviral properties.SOLUTION: A functional composition contains water-soluble and water-insoluble copper compounds at a mass ratio of copper in each compound ranging from 1:5 to 1:300, and also includes a binder and water. This functional composition is applied to or impregnated into paper materials.SELECTED DRAWING: None

Description

Application for application of Article 30, Paragraph 2 of the Patent Act filed (1) Proceedings Publication date: July 21 to July 31, 2022 Publication location: Japan Society of Packaging Science website (http://www.spstj.jp/) (2) Online conference presentation Date held: July 21, 2022 Meeting name: 31st Annual Conference of Japan Society of Packaging Science Location: Oral presentation using the online conference system Zoom

The present invention relates to a functional composition having anticorrosion and antiviral properties, functional paper materials such as paper and paperboard containing the same, and functional cardboard.

Cardboard is used as a packaging material in a variety of situations, and products suitable for specific uses are being considered. Corrugated board may generate reducing sulfur compounds such as hydrogen sulfide derived from the paperboard manufacturing process, and these reducing sulfur compounds may react with silver and copper, causing them to rust and discolor. . For this reason, there is a problem in that ordinary cardboard is difficult to use for packaging precision instruments, jewelry, etc. that contain copper or silver.

On the other hand, Patent Document 1 proposes an anticorrosive composition containing a water-soluble inorganic acid salt such as copper sulfate, an alkaline component such as sodium hydroxide, and a binder. Corrugated cardboard coated with this anticorrosive composition exhibits adsorption and removal properties that adsorb and remove reducing sulfur compounds, and prevents copper and silver contained in packaged items from rusting and discoloring. It can be used as

In addition, the water-soluble inorganic acid salt copper sulfate in the anticorrosive composition described in Patent Document 1 is known to also exhibit antiviral properties.

Japanese Patent No. 4950194

Corrugated cardboard coated with the anticorrosion composition described in Patent Document 1 exhibits antiviral properties, but the water-soluble inorganic acid salts that exert the effect are harmful to living organisms, so it is difficult to use during transportation, packaging, etc. Furthermore, if the surface of the cardboard is splashed with water while being used as a partition, etc., or left in a high humidity environment for a long time, water-soluble components may adhere to the skin, etc., potentially affecting the human body. .

Therefore, the purpose of this invention is to improve the safety of such functional cardboard to the human body.

In this invention, by substituting a part of the water-soluble copper compound with a water-insoluble copper compound, specifically, the mass ratio of the water-soluble copper compound and the water-insoluble copper compound to the copper contained is 1:5 to 1: The above-mentioned problem was solved by a liquid functional composition containing a binder and water.

Water-insoluble copper compounds also have anti-corrosive and anti-viral properties, allowing the desired effects to be achieved while reducing the amount of water-soluble copper compounds that tend to adhere to the skin.

The functional composition of the present invention may have a water-soluble copper compound content of less than 1% by mass, calculated as copper sulfate pentahydrate.

Further, the functional composition according to the present invention may have an embodiment in which the pH is 5.0 or more and less than 6.3.

Furthermore, the functional composition of the present invention can be in a form in which the viscosity of the liquid is 100 mPa·sec or more.

The functional composition of this invention can be used as a functional paper material by coating or impregnating it into paper or paperboard. This functional paper material can exhibit, for example, anticorrosive, deodorizing, and antiviral properties. Cardboard using this functional paper material for the outer liner not only exhibits these effects, but is also highly safe even when directly contacted with the skin.

The functional composition according to the present invention exhibits similar functions compared to conventional compositions, but has a high proportion of water-insoluble copper compounds, which can reduce the amount that adheres to the skin when it comes into contact with it. . As a result, products using paper materials coated or impregnated with it can exhibit anticorrosion and antiviral properties, and can ensure higher safety than before.

Hereinafter, this invention will be described in detail by citing embodiments. The present invention relates to a functional composition having anticorrosion and antiviral properties, a functional paper material coated or impregnated with the composition, and a functional corrugated board using the same.

The functional composition according to the present invention contains a water-soluble copper compound and a water-insoluble copper compound. Hereinafter, the term "copper compound" refers to both of these. Of these, a water-soluble copper compound is a copper compound that dissolves in water at room temperature. Specifically, it is a copper compound that has a solubility in water at room temperature of 0.1 g/100 ml or more. If it is water-soluble, it will adhere easily when it comes into contact with the skin, etc., and it is desirable that the mass ratio of such a water-soluble copper compound with high solubility is small. Examples of such water-soluble copper compounds include copper sulfate hydrate, cupric chloride, and copper acetate.

On the other hand, a water-insoluble copper compound is a copper compound that is insoluble in water at room temperature. Specifically, it is preferable for the copper compound to have a solubility in water at room temperature of less than 0.1 g/100 ml. If the copper compound is water-insoluble, it is less likely to have an effect when it comes into contact with the skin, etc., and is safer when it comes into contact with the skin, etc., even when used in large quantities, compared to water-soluble copper compounds. Examples of such water-insoluble copper compounds include basic copper sulfate, basic copper chloride, and basic copper carbonate.

The water-soluble copper compound and the water-insoluble copper compound used in this invention can be those that maintain equilibrium with each other in water and whose mass ratio varies depending on conditions such as pH. In the above compounds, copper sulfate hydrate and basic copper sulfate are in equilibrium in water, and the mass ratio can be adjusted by pH. Similarly, the combination of cupric chloride and basic copper chloride also reaches equilibrium in water.

The functional composition according to the present invention needs to contain copper contained in the water-soluble copper compound and the water-insoluble copper compound at a mass ratio of 1:5 to 1:300, and 1:10 to 1. :200 is preferable. If the mass ratio of the water-soluble copper compound is higher than 1:5, a large amount will adhere to the skin of a person who comes into contact with the paper material using the functional composition, which is not preferable for ensuring high safety. On the other hand, increasing the mass ratio of the water-insoluble copper compound beyond 1:300 disrupts the equilibrium state, which makes it practically difficult.

The functional composition according to the present invention preferably has a content of less than 1% by mass, more preferably 0.5% by mass or less, calculated based on the mass of copper contained in the water-soluble copper compound and converted into copper sulfate _pentahydrate ( _CuSO4.5H2O ). If the content is 1% by mass or more, the adhesion of the water-soluble copper compound when it comes into contact with the paper material using the functional composition is likely to be in a non-negligible amount. Although a smaller content is preferable, a more realistic content of 0.05% by mass or more is required due to the equilibrium with the water-insoluble copper compound.

The functional composition according to the present invention calculates the amount of copper contained in the water-insoluble copper compound by converting it into basic copper sulfate (CuSO ₄ . [3Cu(OH) ₂ ] .1/2H ₂ O). The amount is preferably 3.5% by mass or less, more preferably 3.2% by mass or less. If it exceeds 3.5% by mass, it becomes difficult to adjust the pH and the dispersibility of the water-insoluble copper compound in the liquid functional composition decreases, which may make uniform coating or impregnation difficult. On the other hand, the content of the water-insoluble copper compound is preferably 2.5% by mass or more, more preferably 2.9% by mass or more. If the content is too small, not only will it be necessary to apply or impregnate a large amount of the functional composition in order to exhibit the effect, but there is also a risk that the amount of water-soluble copper compounds in equilibrium will increase too much.

The functional composition according to the present invention may contain, in addition to the water-soluble copper compound and the water-insoluble copper compound, a pH adjuster for adjusting the pH. Inorganic salts can be suitably used as the pH adjuster, and examples thereof include sodium hydroxide, ammonium hydroxide, trisodium phosphate, sodium carbonate, and borax.

In the functional composition of the present invention, the content of the pH adjuster is preferably 1.5% by mass or more, and more preferably 1.7% by mass or more. If the content is too small, it is difficult to maintain the equilibrium, and it becomes difficult to adjust the mass ratio of the copper compound as targeted. On the other hand, it is preferably 1.9% by mass or less, and more preferably 1.8% by mass or less. If the content is too large, the pH will rise too much, and it becomes difficult to adjust the mass ratio of the copper compound as targeted.

The functional composition according to the present invention is an aqueous solution or dispersion having the above composition, and the pH is preferably 5.0 or more and less than 7, and more preferably less than 6.3. At a pH of 7 or more, the copper compound oxidizes and turns black, decreasing the anticorrosive and antiviral properties. At a pH of 6.3 or more, the redispersibility of the water-insoluble copper compound in the liquid functional composition tends to decrease. On the other hand, at a pH of 5.0 or less, the balance is too far in favor of the water-soluble copper compound, increasing the ratio of the water-soluble copper compound, and the compound becomes too easily attached to the skin when it comes into contact with the skin, etc.

Furthermore, the functional composition according to the present invention may contain a salt produced as a result of pH adjustment. Examples include sodium sulfate and sodium chloride.

The functional composition according to the present invention contains a binder. A binder fixes a copper compound, an alkali component, etc. by coating or impregnating a paper material with a composition. It contains a polymer and may be water-soluble or water-dispersible. Specifically, synthetic rubber latex such as styrene-butadiene latex, poly(meth)acrylic acid ester or copolymer latex of this with styrene, vinyl acetate, etc., polyurethane, partially saponified polyvinyl acetate, polyvinyl alcohol, Examples include fiber derivatives such as methylcellulose and carboxymethylcellulose, and water-soluble polymers such as sodium polyacrylate.

In the functional composition according to the present invention, the binder content is preferably 0.3% by mass or more as solid content, more preferably 0.5% by mass or more. If the amount is too small, the copper compound will be difficult to be fixed to the paper material, and there is a risk that it will peel or come off. On the other hand, it is preferably 2% by mass or less, and more preferably 1% by mass or less. If the amount is too large, the viscosity during coating or impregnation may increase too much, making it difficult to work.

The functional composition according to the present invention may contain other additives as long as their functions are not impaired. Examples of such additives include viscosity modifiers.

The functional composition of the present invention preferably has a viscosity of 100 mPa·sec or more. If it is less than 100 mPa·sec, it becomes difficult to coat or impregnate the paper material and fix the copper compound to the surface. There are no particular limitations on the method of coating or impregnation, and the viscosity may be high as long as it allows coating or impregnation, but it is preferable that the viscosity is 500 mPa·sec or less.

The functional composition according to the present invention has anticorrosion, deodorizing, and antiviral properties by coating, spraying, dipping, impregnating, printing, etc. on paper material at the above pH and viscosity. It is possible to obtain functional paper materials that exhibit the following properties. Specifically, the copper compound absorbs and removes reducing sulfur compounds, exhibiting anticorrosion and deodorizing properties, and also exhibits antiviral properties.

The paper material used in the present invention is not particularly limited, and may be paperboard or paper. Examples of the paperboard include corrugated paperboard, paperboard for folding cartons, and other paperboards. Examples of the corrugated base paper include liners such as kraft liner, jute liner, interior liner, etc., and medium corrugated paper such as semi-corrugated paper and special paper. Examples of the above-mentioned paperboard for folding cartons include white paperboard such as manila board and white board, yellow board, chip board, colored board, and the like. Examples of the other paperboards mentioned above include paper tube base paper, wamp, and the like. Some of these paperboards, such as kraft liner, contain sulfur compounds and generate reducing sulfur compounds, which can be absorbed and removed by the functional composition of the present invention. Furthermore, in consideration of packaging applications, it is generally desirable that these paperboards have a basis weight of 100 g/m ² or more and 950 g/m ² or less before being coated or impregnated with the composition. On the other hand, examples of paper include wallpaper, shoji paper, and wrapping paper. These papers preferably have a basis weight of 40 g/m ² or more and 100 g/m ² or less before being coated or impregnated with the composition.

The functional paper material according to the present invention can be used, for example, as wallpaper for architectural interiors or as shoji paper. Further, it can be used as is as a packaging material, or as a liner or core of corrugated cardboard. When these packaging materials are used, they can be suitably used as packaging materials for home appliances, devices, and various electronic components. Due to the high proportion of water-insoluble copper compounds, it is possible to obtain a highly safe packaging material that is less likely to adhere to the skin or the like than conventional products even if it comes into direct contact with the packaging. In particular, when the functional paper material according to the present invention is used for the front liner of corrugated cardboard, it exhibits anticorrosion, deodorizing, and antiviral properties, and also suppresses the adhesion of copper compounds to the skin even when it comes in contact with bare skin. It can be made into functional cardboard with high safety. Furthermore, this functional cardboard can be suitably used, for example, as a partition in an office or a shelter.

The copper content in the functional composition of the functional paper according to the present invention is preferably 0.1 g/ ^m2 or more, and more preferably 0.15 g/ ^m2 or more. If it is less than 0.1 g/ ^m2 , the effect obtained by coating or impregnation may not be fully exhibited.

As an indicator of the safety of the functional paper material according to the present invention, for example, the amount of copper compound eluted into water during an elution test can be used, and if it is small, it can be judged that the safety is high.

Next, the functional composition and functional paper material according to the present invention will be illustrated in more detail by giving examples in which the present invention was actually implemented. First, I will list the raw materials used.

<Copper Compounds>
Copper sulfate pentahydrate: Kishida Chemical Co., Ltd.: special grade reagent, molecular weight = 246.69
<Binder>
Carboxy-modified SBR latex: Nalstar SR103, solid content 44%, manufactured by Nippon A&L Co., Ltd.
Styrene-acrylic resin emulsion: JONCRYL PDX-7357 manufactured by BASF Japan Ltd., solid content 48%
Ethylene-vinyl acetate copolymer emulsion: Sumitomo Chemical Co., Ltd.: Sumikaflex S-355HQ, solid content 55%
One-component polyurethane dispersion: Mitsui Chemicals, Inc.: Takelac W6061, solids content 30%
<Viscosity modifier>
Urethane modified polyether: San Nopco: SN Thickener 612, solids content 40%
・High-molecular-weight special nonionic thickener... ADEKA: Adekanol UH420, solids content 30%
<pH Adjuster>
・5% by mass sodium hydroxide - Kishida Chemical Co., Ltd.

Next, the measurement method and the method for preparing the samples will be described.
<pH test>
Measurement was performed using a pH meter F-51 manufactured by Horiba Ltd.

<Viscosity measurement>
Measured at 23° C. using a B-type viscometer manufactured by Tokimec Co., Ltd. When the viscosity is 100 mPa·S or less, No. Measurements were made using one rotor at 30 rpm. When the viscosity is 100 mPa·S or more, No. Measurements were made using two rotors at 60 rpm.

<Color observation>
After preparing the functional composition of each example and storing it at 40°C for 3 days, visually observe the color tone of the supernatant and sediment to confirm that the copper compound has not been oxidized and turned black. did.

<Redispersibility measurement>
100 g of the functional composition according to each example was placed in a plastic container, sealed, and shaken at 100 rpm for 10 minutes using a multishaker MMS300 manufactured by Tokyo Rikakikai Co., Ltd., and then allowed to stand for 5 minutes, after which the state of the liquid was visually observed. Those that maintained a uniformly dispersed state were rated as "good", and those in which sediment was observed were rated as "poor".

<Measurement of water-insoluble copper compound content>
Using a micro high-speed centrifuge (manufactured by Hitachi Koki Co., Ltd.: himac CF15R), the functional composition according to each example placed in a plastic container was centrifuged at 10,000 G for 30 minutes, and the sediment was filtered with filter paper. After washing with distilled water, it was dried at 105°C in a hot air dryer. The mass of the obtained residue was measured, and the copper content of the water-insoluble copper compound in the functional composition was calculated. A qualitative test as basic copper sulfate was conducted by analyzing Cu・S・O using a scanning electron microscope-energy dispersive X-ray analysis (manufactured by JEOL Ltd.: JSM-6010PLUS/LA). .

<Measurement of Water-Soluble Copper Compound Content>
In the above-mentioned measurement of the water-insoluble copper compound content, the supernatant obtained by centrifuging the functional composition according to each example was measured using a polarized Zeeman atomic absorption spectrophotometer (Z-2010, manufactured by Hitachi High-Tech Science Corporation), and the copper ion concentration in the supernatant was calculated from a calibration curve using a copper standard solution, and the copper content of the water-soluble copper compound in the functional composition was calculated.

<Coating sample preparation procedure>
Liner base paper (manufactured by Rengo Co., Ltd.: RKA170, basis weight 170 g/m ² ) was cut into pieces of 25 cm in length and 20 cm in width, and was attached to a glass plate with adhesive tape. On the other hand, each of the above-mentioned raw materials was prepared in the blending ratio shown in Table 1 to obtain a functional composition having the physical properties shown in the same table. The functional composition of each example was applied to the liner base paper pasted on a glass plate using a bar coater so that the wet coating amount before drying was 10 g/m ² , and then it was coated in a hot air dryer. A coated sample was obtained by drying at 105° C. for 1 minute. In addition, in the functional composition and coating sample, copper sulfate pentahydrate used as a raw material becomes copper sulfate pentahydrate, which is a water-soluble copper compound, depending on the pH adjusted as a functional composition. There are two types: those that remain as they are and those that have become basic copper sulfate, a water-insoluble copper compound.

<Corrosion prevention/deodorization: hydrogen sulfide removal performance test>
The coating samples prepared in each example were cut into 6.5 cm square pieces, placed in a Tetler bag, filled with 1000 ml of hydrogen sulfide gas having a concentration of 248 ppm, and left at 23° C. for 10 minutes. Thereafter, the hydrogen sulfide concentration (ppm) in the bag was measured with a gas detection tube (manufactured by Komei Rikagaku Kogyo Co., Ltd.: Model 120SB), and the removal rate (%) was calculated from the hydrogen sulfide gas concentration before the test.

<Elution test>
The coating sample prepared in each example was cut into 1 cm square pieces, placed in an Erlenmeyer flask, added with 2 ml of distilled water as a leaching liquid, and shaken at room temperature at 100 rpm x 30 minutes in the multi-shaker described above to perform an elution test. went. The copper ion concentration in the obtained test solution was analyzed using a polarized Zeeman atomic absorption spectrophotometer, and those with a copper ion concentration of less than 1 mg/l were marked "○", and those with a copper ion concentration of 1 mg/l or more were marked "x". rated it as.

<Antiviral test>
According to the ISO21702 method, a 5 cm square coated sample was used as a sample, and the above liner base paper was used as a test control. H3N2:ATCC VR-1679 was used as the influenza A virus in the test. The antiviral properties of the above liner base paper were evaluated using a nylon film as a test control. As a criterion, calculate the antiviral activity value R = Ut - At (Ut: common logarithmic value of the viral infectious titer of the test control, At: common logarithmic value of the viral infectious titer of the sample), and 2>R. were evaluated as "x" indicating no antiviral properties, "○" indicating antiviral properties when 2≦R≦3, and "◎" indicating excellent antiviral properties when 3<R. .

In Examples 1 to 3, where the pH was adjusted, the color of the supernatant lightened as the pH increased, and the mass ratio of copper as copper sulfate pentahydrate, a water-soluble copper compound that is the source of coloring, decreased. As a result, within the range of these Examples, the higher the pH, the smaller the amount of elution and the safer the coating sample obtained. This coating sample showed good results in both the hydrogen sulfide removal test and the antiviral test. Examples 4 and 5, in which the binder was changed from Example 3, also showed almost similar favorable results. Example 6, in which the thickener was changed, also showed almost similar favorable results.

Comparative Example 1 shows the results of a hydrogen sulfide removal test and an antiviral test for the control liner base paper. The hydrogen sulfide removal performance was barely exhibited, and the antiviral properties were not sufficient.

In Comparative Example 2, in which the pH of the composition was 3.5 without the pH adjuster in Example 1, the copper sulfate pentahydrate used as the raw material was included in the composition as it was. The hydrogen sulfide removal performance of the coating sample was low and a high amount of elution was observed, resulting in insufficient safety. In Comparative Example 3, in which the amount of pH adjuster in Example 1 was reduced and the pH was 4.2, the mass ratio of copper in the water-soluble copper compound copper sulfate pentahydrate was high, and although the hydrogen sulfide removal performance and antiviral properties were exhibited, the amount of elution was too high. In Comparative Examples 4 to 6, in which the pH adjuster was further increased from Example 6, the pH value of the composition became too high, and copper existed as a water-insoluble copper compound, causing problems with redispersibility, and the viscosity also decreased, making it difficult to apply. In Comparative Examples 5 and 6, the hydrogen sulfide removal performance also decreased.

Claims (6)

A functional composition containing a water-soluble copper compound and a water-insoluble copper compound in a mass ratio of copper contained in a range of 1:5 to 1:300, and containing a binder and water. The functional composition according to claim 1, wherein the content of the water-soluble copper compound is less than 1% by mass. The functional composition according to claim 2, which has a pH of 5.0 or more and less than 6.3. The functional composition according to claim 3, which has a viscosity of 100 mPa·sec or more. A functional paper material obtained by coating or impregnating paper or paperboard with the functional composition according to any one of claims 1 to 4. A functional cardboard using the functional paper material described in claim 5 as the front liner.