阅读说明：本技术 抗菌纸及其制造方法 (Antibacterial paper and manufacturing method thereof ) 是由 糸井隆 铃木佑佳 于 2020-04-07 设计创作，主要内容包括：本发明的抗菌纸含有抗菌剂,且该抗菌纸每0.1g中的钙含量为500ppm以上。本发明的抗菌纸的制造方法包括：抄纸工序,其使用德国硬度为5°dH以上的抄纸用水,通过湿式抄纸形成湿纸；抗菌剂赋予工序,其对上述湿纸赋予使用抗菌剂及其稀释用水所制备的抗菌剂含有液；及干燥工序,其对经过上述抗菌剂赋予工序的上述湿纸进行加热干燥。上述稀释用水的德国硬度为上述抄纸用水的德国硬度以下。(The antibacterial paper contains an antibacterial agent, and the calcium content of the antibacterial paper per 0.1g is more than 500 ppm. The method for manufacturing the antibacterial paper comprises the following steps: a papermaking step of forming a wet paper by wet papermaking using papermaking water having a German hardness of 5 DEG dH or more; an antimicrobial agent application step of applying an antimicrobial agent-containing liquid prepared by using an antimicrobial agent and water for diluting the same to the wet paper web; and a drying step of heating and drying the wet paper having passed through the antimicrobial agent application step. The German hardness of the dilution water is not more than the German hardness of the papermaking water.)

1. An antibacterial paper contains an antibacterial agent,

the calcium content of the antibacterial paper per 0.1g is 500ppm or more, preferably 510ppm or more, and more preferably 515ppm or more.

2. The antibacterial paper according to claim 1, wherein the calcium content per 0.1g of the antibacterial paper is 800ppm or less, preferably 750ppm or less, more preferably 700ppm or less.

3. The antibacterial paper according to claim 1 or 2, wherein the calcium content per 0.1g of the antibacterial paper is 515ppm or more and 700ppm or less.

4. The antimicrobial paper according to any one of claims 1 to 3, wherein the antimicrobial agent is an organic antimicrobial agent.

5. The antibacterial paper according to any one of claims 1 to 4, wherein the antibacterial agent is a cationic antibacterial agent.

6. The antimicrobial paper of claim 5, wherein the antimicrobial agent is a quaternary ammonium salt.

7. The antibacterial paper according to claim 6, wherein the quaternary ammonium salt is 1 or more selected from cetylpyridinium chloride, benzethonium chloride, dequalinium chloride, didecyldimethylammonium chloride, cetylbenzylalkyl ammonium phosphate, and benzalkonium chloride.

8. The antibacterial paper according to any one of claims 1 to 7, wherein the antibacterial agent is a benzalkonium salt represented by the following formula (1),

in the formula (1), R¹And R²The same or different, represents methyl, ethyl or C8-20 linear or branched alkyl or alkenyl, X^－Represents a monovalent anion.

9. The antibacterial paper according to claim 8, wherein the formula (1) is represented by X^－The monovalent anion is an alkyl phosphate-containing anion represented by the following formula (2)An ionic active group, a hydroxyl group, a carboxyl group,

in the formula (2), R³And R⁴One of them represents a linear or branched alkyl group or alkenyl group having 6 to 20 carbon atoms, and the other represents a hydrogen atom, a methyl group or an ethyl group.

10. The antibacterial paper according to claim 8 or 9, wherein the benzalkonium salt is 1 or more selected from benzalkonium chloride and benzalkonium cetyl phosphate.

11. The antibacterial paper according to any one of claims 1 to 10, wherein the paper is produced according to JIS L1902: 2015 "antibacterial activity test method and antibacterial effect of fiber product" is 1 or more, preferably 1.5 or more, and more preferably 2 or more.

12. The antibacterial paper according to claim 11, wherein the antibacterial activity value is 6 or less.

13. The antibacterial paper according to any one of claims 1 to 12, wherein the antibacterial paper is an antibacterial paper for an absorbent article.

14. An absorbent article having the antibacterial paper according to any one of claims 1 to 13.

15. The absorbent article according to claim 14, comprising: a front sheet forming a skin-facing surface, a back sheet forming a non-skin-facing surface, and a liquid-retentive absorbent member disposed between the sheets,

the absorbent comprises an absorbent core and a core-wrapped sheet covering the absorbent core,

the core-spun sheet is the antibacterial paper.

16. A method of making an antimicrobial paper comprising:

a papermaking step of forming a wet paper by wet papermaking using papermaking water having a German hardness of 5 DEG dH or more, preferably 5.5 DEG dH or more, more preferably 6 DEG dH or more;

an antimicrobial agent application step of applying an antimicrobial agent-containing liquid prepared using an antimicrobial agent and water for dilution thereof to the wet paper web; and

a drying step of heating and drying the wet paper having passed through the antimicrobial agent application step;

the German hardness of the dilution water is not more than the German hardness of the papermaking water.

17. The method for producing an antibacterial paper according to claim 16, wherein the water for papermaking has a german hardness of 12 ° dH or less, preferably 10 ° dH or less, more preferably 8 ° dH or less.

18. The method for producing antibacterial paper according to claim 16 or 17, wherein the water for papermaking has a german hardness of 6 ° dH or more and 8 ° dH or less.

19. The method for producing antibacterial paper according to any one of claims 16 to 18, wherein the german hardness of the dilution water is smaller than the german hardness of the papermaking water.

20. The method for producing the antibacterial paper according to any one of claims 16 to 19, wherein the german hardness of the dilution water is 4 ° dH or less, preferably 3 ° dH or less, and more preferably 0 ° dH.

21. The method for producing an antibacterial paper according to any one of claims 16 to 20, wherein the german hardness of the diluting water is 0 ° dH or more and 3 ° dH or less.

22. The method for producing an antibacterial paper according to any one of claims 16 to 21, wherein the german hardness of the dilution water/the german hardness of the papermaking water is 0.7 or less, preferably 0.5 or less, and more preferably 0.

23. The method for producing antibacterial paper according to any one of claims 16 to 22, wherein the german hardness of the dilution water/the german hardness of the papermaking water is 0 or more and 0.5 or less.

24. The method for producing an antibacterial paper according to any one of claims 16 to 23, wherein the antibacterial agent is an organic antibacterial agent.

25. The method for producing an antibacterial paper according to any one of claims 16 to 24, wherein the antibacterial agent is a cationic antibacterial agent.

26. The method of manufacturing antibacterial paper according to claim 25, wherein the cationic antibacterial agent is a quaternary ammonium salt.

27. The method for producing antibacterial paper according to claim 26, wherein the quaternary ammonium salt is 1 or more selected from cetylpyridinium chloride, benzethonium chloride, dequalinium chloride, didecyldimethylammonium chloride, cetylbenzylalkyl ammonium phosphate, and benzalkonium chloride.

28. The method for producing an antibacterial paper according to any one of claims 16 to 27, wherein the antibacterial paper is an antibacterial paper for an absorbent article.

29. A method of manufacturing an absorbent article, comprising: combining 1 or 2 or more members other than the antibacterial paper with the antibacterial paper according to any one of claims 1 to 13 or the antibacterial paper produced by the production method according to any one of claims 16 to 28.

30. The method of manufacturing an absorbent article according to claim 29, wherein a topsheet forming a skin-facing surface of the absorbent article, a backsheet forming a non-skin-facing surface of the absorbent article, and a liquid-retentive absorbent member disposed between the two sheets are used as the other members, the absorbent member comprising an absorbent core and a core-wrapped sheet wrapping the absorbent core,

in the step, the antibacterial paper is used as the core-spun sheet, and the core-spun sheet is laminated with the absorbent core, the front sheet, and the back sheet.

Technical Field

The invention relates to an antibacterial paper containing an antibacterial agent.

Background

Conventionally, in absorbent articles such as disposable diapers and sanitary napkins, an antimicrobial agent has been incorporated in order to suppress an unpleasant odor or the like derived from excrement when worn. Patent document 1 describes an antibacterial paper that can be used as a component of an absorbent article, for example, a core-spun sheet covering an absorbent core. In the examples of patent document 1, a coating liquid containing an antibacterial agent is produced using water having a hardness within a predetermined range, and the coating liquid is applied to wet paper, thereby producing paper having antibacterial properties.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-

Disclosure of Invention

The invention relates to an antibacterial paper containing an antibacterial agent and calcium.

Preferably, the antibacterial paper of the present invention contains calcium in an amount of 500ppm or more per 0.1g of the antibacterial paper.

The present invention is also a method for producing an antibacterial paper, comprising a papermaking step of forming a wet paper by wet papermaking using papermaking water having a german hardness of 5 ° dH or more.

Preferably, the production method of the present invention includes an antimicrobial agent application step of applying an antimicrobial agent-containing liquid prepared by using an antimicrobial agent and water for dilution thereof to the wet paper.

Preferably, the production method of the present invention includes a drying step of heating and drying the wet paper having passed through the antimicrobial agent application step.

In the production method of the present invention, the german hardness of the diluting water is preferably not more than the german hardness of the papermaking water.

Other features of the present invention will become apparent from the description of the claims and the following description.

Detailed Description

When an absorbent article is worn, the absorbent core is deformed by an external force such as the body pressure of the wearer and swells by absorbing body fluid such as excreted urine, and therefore the core-wrapped sheet covering the absorbent core is required to be soft and easily bendable so as to follow the deformation or swelling of the absorbent core. In addition, in many cases, the absorbent article is required to have flexibility in other components other than the core sheet.

The present invention relates to a soft antibacterial paper having antibacterial properties. Another object of the present invention is to provide a method for producing an antibacterial paper, which can efficiently produce a soft antibacterial paper having antibacterial properties.

In general, the hardness of water used for wet papermaking in a paper mill (hereinafter also referred to as "papermaking water") is usually 2 to 4.5 ° dH in a german durometer. Further, since clogging of the piping of water due to scale formation is concerned, it is general to avoid the use of water having high hardness. The present inventors have conducted various studies and as a result, have found that soft paper can be obtained by wet-papermaking according to a conventional method using papermaking water having a higher german hardness than ordinary papermaking water. It has also been found that soft paper produced using the papermaking water having high hardness has a higher calcium content than paper produced using ordinary papermaking water.

It is generally known that if an antibacterial agent and metal ions coexist, the metal ions inhibit the antibacterial performance of the antibacterial agent. It is known that the efficacy (bactericidal performance) of an inverted soap such as a benzalkonium salt represented by the following formula (1) is easily affected by the hardness of water. According to w.s.mueller and o.b.seely [ Soap & saitry Chemicals,27, No.6,131(1951) ], the inhibitory force of the metal ions having 2 and 3 valences against the bactericidal performance of the reversed Soap is stronger than that of the metal ions having 1 valences, and the ratio of the inhibitory force can be regarded as the metal ions having 1 valences: 2-valent metal ion: and (3) a metal ion of 1: 100: 1000. in general, when paper having antibacterial properties is produced, the antibacterial agent is typically diluted with the same water as the paper-making water and used. If water having a high hardness such as a german hardness of 5 ° dH or more is used as dilution water, which is water for papermaking, the water having a high hardness contains a relatively large amount of metal ions (calcium ions, magnesium ions, and the like). Therefore, the opportunity of the antibacterial agent to react with the metal ions derived from the dilution water to generate metal salts (scum) increases, and the designed antibacterial performance cannot be obtained. The present inventors have conducted various studies on the above problem and found that the antibacterial property and flexibility of paper can be achieved by differentiating the papermaking water from the dilution water and setting the german hardness of the latter to be lower than that of the former.

The antibacterial paper of the present invention contains an antibacterial agent. The antibacterial property of the antibacterial paper of the present invention is exhibited by the antibacterial agent contained in the antibacterial paper. The antibacterial agent used in the present invention is not particularly limited, and an antibacterial agent capable of inhibiting the growth of bacteria can be used, and it is preferable to use an antibacterial agent that acts to eliminate the odor-causing source, that is, an antibacterial agent that acts to inhibit the growth of skin resident bacteria, intestinal bacteria, and enzymes derived from these bacteria, which are responsible for the odor. For example, an antibacterial agent that inhibits or kills the proliferation and growth of bacteria associated with the production of urine odor can be used. The antibacterial agent used in the present invention includes 1 or more selected from inorganic antibacterial agents, organic antibacterial agents and the like.

Examples of the inorganic antibacterial agent include 1 or more selected from fine particle powders and needle crystals obtained by supporting antibacterial metal ions such as silver, zinc, copper, iron, magnesium, calcium, aluminum, antimony, and bismuth, and salts thereof on a carrier.

The carrier may be 1 or more selected from zeolite, silica gel, low molecular glass, calcium phosphate, zirconium phosphate, silicate, titanium oxide, and the like.

The organic antibacterial agent may include 1 or more selected from cationic antibacterial agents, anionic antibacterial agents and nonionic antibacterial agents.

Examples of the anionic antibacterial agent include 1 or more selected from piroctone olamine [ 1-hydroxy-4-methyl-6- (2,4, 4-trimethylpentyl) -2(1H) -pyridone monoethanolamine salt ], potassium oleate, sodium 1-pentane sulfonate, sodium 1-decane sulfonate, sodium butylnaphthalene sulfonate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium hexadecyl sulfate and the like.

Examples of the nonionic antibacterial agent include 1 or more selected from chlorhexidine hydrochloride, chlorhexidine gluconate, triclocarban, triclosan, isopropylmethylphenol, halocarban, parabens, and the like.

The antibacterial agent used in the present invention preferably comprises an organic antibacterial agent. This is because the organic antibacterial agent has a higher antibacterial effect than inorganic antibacterial agents such as zinc oxide-containing antibacterial agents and silver-containing antibacterial agents. In addition, since the inorganic antibacterial agent is generally water-insoluble, it is preferable to use an organic antibacterial agent as the antibacterial agent from the viewpoint of stable supply when the antibacterial agent is applied to paper by a non-contact application method such as spraying with a sprayer.

As described below, in the production of the antibacterial paper of the present invention, the antibacterial agent-containing liquid prepared by diluting the antibacterial agent with water for dilution is used, and as a result, the antibacterial agent used in the present invention is preferably water-soluble to some extent or dispersible in water, from the viewpoint of facilitating the production of the antibacterial agent-containing liquid and producing the antibacterial paper with high efficiency, and from the viewpoint of preventing clogging in the step of spraying the antibacterial agent-containing liquid. Specifically, the residual ratio of the antibacterial agent used in the present invention, as measured by the following method, is preferably less than 0.5% by mass, more preferably 0.3% by mass or less, and most preferably 0% by mass. Namely 0 mass% or more. In the following production examples, 2 types of antibacterial agents, i.e., the antibacterial agents a and B, were used, and as a result, the residual ratio of the antibacterial agent a was 0.01 mass%, and the residual ratio of the antibacterial agent B was 0.005 mass%.

< method for measuring residual Rate >

10g of an antibacterial agent to be measured and 90g of deionized water (water temperature 20 ℃) were placed in a beaker having a capacity of 100mL, and the mixture was sufficiently stirred to prepare an antibacterial agent-containing solution. The antibacterial agent-containing solution was allowed to stand at 25 ℃ in a gas atmosphere for 1 hour, and then poured into a 180-mesh net. The mass of the residue that did not pass through the web was measured, and the measured value was defined as a residual amount M1. The residual ratio (% by mass) of the antibacterial agent was calculated from the residual amount M1 and the initial mass M0(═ 10g) of the antibacterial agent by the following formula. The residual ratio (% by mass) was (M1/M0) × 100

As a preferable example of the antibacterial agent used in the present invention, a cationic antibacterial agent which is one of organic antibacterial agents can be cited. If the antibacterial agent contained in the antibacterial paper is a cationic antibacterial agent, the growth of bacteria derived from excrement can be effectively suppressed, and the growth of the bacteria can be effectively suppressed.

This effect is particularly remarkable when the antibacterial paper of the present invention is used as an antibacterial paper for an absorbent article, that is, as a component member (for example, a core-wrapped sheet) of an absorbent article such as a disposable diaper. For example, generation of an unpleasant odor when worn, skin troubles of the wearer, and the like can be effectively suppressed.

The cationic antibacterial agent has an effect of inhibiting the growth of microorganisms or enzymes derived from microorganisms, which cause the generation of unpleasant odor components, in a liquid phase of excrement such as urine. This action of the cationic antibacterial agent eliminates the generation source of odor components in the absorbent article, and exerts a deodorizing effect.

The biological deodorizing action of such cationic antibacterial agents is effective against a wide variety of odor components ranging from acidic to basic, such as lower fatty acids, phenols, thiols, ketones, aldehydes, and amines.

Among cationic antibacterial agents, cationic antibacterial agents containing quaternary ammonium salts are preferable in that they can exhibit high antibacterial properties at low concentrations.

The quaternary ammonium salt is not particularly limited and may include, for example: an alkylpyridinium salt, a benzylium salt, a benzalkonium salt, a monoalkyltrimethylammonium salt, a dialkyldimethylammonium salt, and the like, and 1 or more selected from these can be used.

Among cationic antibacterial agents containing quaternary ammonium salts, those containing 1 or more selected from cetylpyridinium chloride, benzethonium chloride, dequalinium chloride, didecyldimethylammonium chloride, benzalkonium phosphate, benzalkonium chloride, and the like are particularly preferable as the quaternary ammonium salts.

Among the benzalkonium salts, especially the benzalkonium salt represented by the following formula (1) is preferable because it can further exhibit high antibacterial properties at a low concentration.

[ chemical formula 1]

In the above formula (1), R¹And R²The same or different, each represents a methyl group, an ethyl group, or a linear or branched alkyl or alkenyl group having 8 to 20 carbon atoms. X^－Represents a monovalent anion.

Of the compounds represented by the above formula (1), 1 species may be used alone, or 2 or more species may be used in combination.

In the above formula (1), R is¹And R²As a preferred combination of (A) and (B), for example, a combination wherein R is¹Is methyl, R²Is a linear or branched alkyl group having 8 to 20 carbon atoms, preferably 8 to 18 carbon atoms.

Further, combinations may be cited in which R is¹And R²These groups are the same and are linear or branched alkyl groups having 8 to 20 carbon atoms, preferably 8 to 18 carbon atoms.

In the above formula (1), X^－The monovalent anion is preferably a halide ion or an anionic active group, for example. The "anionic active group" refers to an ion having an anionic surface active energy.

The anionic active group is preferably one having 6 or more carbon atoms, and particularly preferably one having 10 or more carbon atoms.

The anionic active group is preferably one having 20 or less carbon atoms, and particularly preferably one having 18 or less carbon atoms.

As the above-mentioned anionic active group, it is preferable to use an anionic active group containing a linear or branched alkyl group or alkenyl group.

As such an anionic active group, it is preferable to use one containing 1 or more kinds of anionic active groups selected from, for example, alkyl phosphate, alkyl carboxylate, alkyl sulfonate and alkyl sulfate ester salt, in terms of antibacterial performance.

From the viewpoint of safety (low irritation to the skin), it is particularly preferable to use an anionic active group containing an alkyl phosphate represented by the following formula (2).

[ chemical formula 2]

In the above formula (2), R³And R⁴One of them represents a linear or branched alkyl group or alkenyl group having 6 to 20 carbon atoms, and the other represents a hydrogen atom, a methyl group or an ethyl group.

As R³And R⁴As a preferred combination of (A) and (B), a combination wherein R is as follows is mentioned³Is a hydrogen atom, R⁴Is a linear or branched alkyl group having 8 to 20 carbon atoms, preferably 8 to 18 carbon atoms. The cationic active group (quaternary amine) having a long-chain alkyl group can improve the hand (bulkiness and softness) of the antibacterial paper.

Among the benzalkonium salts, 1 or more selected from benzalkonium chloride and benzalkonium cetyl phosphate is particularly preferably used in terms of high antibacterial properties, safety and quick-acting properties.

In particular, benzalkonium cetyl phosphate is preferable because it has a good balance between antibacterial activity and low irritation to the skin (low water solubility) among organic cationic antibacterial agents and is highly safe.

Therefore, the antibacterial paper of the present invention is particularly effective when used as an antibacterial paper for an absorbent article, that is, a component member (for example, a core-wrapped sheet) of an absorbent article.

As benzalkonium chloride, an antibacterial agent sold under the trade name of Sanisol B-50 manufactured by Kao corporation may be used, and as benzalkonium phosphate, an antibacterial agent sold under the trade name of Sanisol P-2 manufactured by Kao corporation may be used.

The antibacterial paper of the present invention is preferably a paper having a chemical formula according to JIS L1902: 2015 "antibacterial activity test method and antibacterial effect of fiber product" is 1 or more, more preferably 1.5 or more, and still more preferably 2 or more.

The value of the antimicrobial activity value is actually 6 or less.

The antibacterial activity value becomes a pointer to the antibacterial performance of the antibacterial paper, and the larger the value is, the higher the antibacterial performance is evaluated. The antibacterial paper having the antibacterial activity value of the above lower limit or more can effectively inhibit the proliferation of bacteria.

In particular, since the growth of bacteria derived from excrement such as urine can be effectively suppressed, the antibacterial paper is particularly suitable as an antibacterial paper for an absorbent article, that is, a component member (for example, a core-wrapped sheet) of an absorbent article.

Specific measurement methods of the antibacterial activity value are as follows.

< method for measuring antibacterial Activity value >

The measurement was performed by the bacteria solution absorption method (quantitative test method in which test inoculation bacteria solution was directly inoculated onto a test piece) in the above "method for testing antibacterial property and antibacterial effect of fiber product", and the contents of the method not clearly specified in JIS are as follows.

6.5 preparation of nutrient Medium (NB)

8g of nutrient broth (manufactured by Becton, Dickinson and Company) was added to 1000mL of distilled water manufactured by Kanto chemical Co., Ltd, and thoroughly stirred to obtain an aqueous solution, the pH of the aqueous solution was adjusted to 6.9. + -. 0.2, and then sterilized by autoclave to obtain a nutrient medium (NB).

6.11 preparation of agar Medium (EA)

To 1000mL of distilled water produced by Kanto chemical Co., Ltd, were added: bacto manufactured by Becton, Dickinson and Company^TMYeast Extract dehydrate 2.5g, Bacto manufactured by this company^TMTryptone (5.0 g) made of casein from Tryptone (Tryptone), D (+) glucose (1.0 g) made by Fuji film and Wako pure chemical industries, Ltd., and agar (12-15 g) made by Fuji film and Wako pure chemical industries, Ltd., were thoroughly stirred to obtain an aqueous solution, the pH of the aqueous solution was adjusted to 7.2. + -. 0.2, and then sterilized by a high pressure steam sterilizer (CLG40L, autoclave) made by ALP Ltd., at a temperature of 120. + -. 2 ℃ and a pressure of 103 kPa. + -. 5kPa to obtain an agar medium (EA) for pour plate culture.

7 test strains

Bacterial name: coli, WDCM coding: escherichia coli NBRC 3301

7.2.4 preparation of test strains (slant culture medium method)

The slant culture method is as follows. About 10mL of the agar medium (EA) which had been dissolved by heating in advance was injected into a 50mL test tube manufactured by AS ONE, the open end of the test tube was closed with a tampon manufactured by AS ONE, and after sterilization was completed by an autoclave, the test tube was placed in a clean room at an angle of about 15 degrees with respect to the horizontal plane to solidify the contents. The condensate water disappeared was dissolved and solidified again for use. A slant medium was prepared in this manner.

Subsequently, the bacterium (E.coli) was transplanted into the slant medium to prepare preculture A. The slant culture medium (preculture A) into which the bacteria were transplanted was cultured at 37 ℃. + -. 2 ℃ for 24 to 48 hours using a cryostat IJ101W manufactured by Yamato Scientific Co., Ltd, and then stored at 5 to 10 ℃. When the slant medium was smeared with Tremella fuciformis, bacteria were dispersed in the condensed water present in the test tube, and a straight line was drawn from this position to the upper side of the slant. The tip of the tremella aurantialba was taken out of the culture medium once and immersed in the condensed water again, and at this time, the tip was streaked to the upper side of the inclined surface in a meandering manner.

8.1.1.2 preculture B

20mL of the nutrient medium (NB) was placed in a conical flask with a lid, made by AS ONE, having a capacity of 100 mL. 1 colony was scraped from the plate of the above preculture A using Tremella alba, and the colony was inoculated into the culture solution of the flask. Preculture B was prepared in this manner.

8.1.1.3 preculture C

20mL of the nutrient medium (NB) was placed in a conical flask with a lid, made by AS ONE, having a capacity of 100 mL. 0.4mL of the culture solution of preculture B was added to the conical flask with a lid to prepare preculture C.

8.1.2 preparation of test inoculum

The concentration of the pre-culture C after cultivation was adjusted to 1X 10 by using a nutrient medium (NB) diluted 20 times with water at room temperature using a spectrophotometer (U-3310) manufactured by Hitachi High-Technologies, Ltd⁵～3×10⁵CFU/mL. Test inoculum was prepared in this manner.

8.1.4 test procedures

8.1.4.1 inoculation of test strips

The antibacterial paper to be measured was placed in a sample bottle as a test piece, and the test piece was inoculated with the above-mentioned test inoculum solution as an inoculum. Specifically, 0.2mL of a seed solution was inoculated into each of a plurality of portions on one surface of a test piece in a sample bottle using PIPEMAN (P200) manufactured by Gilson Company. In this case, the inoculum does not contact the walls and the cap of the sample vial.

8.1.4.2 Wash immediately after inoculation

Immediately after the test piece was inoculated, 20mL of physiological saline was added to each of the sample bottles of the 3 test sample specimens and the 3 control sample specimens. The physiological saline was prepared by adding 8.5g of Fuji film and sodium chloride (available from Wako pure chemical industries, Ltd.) to 1000mL of distilled water (available from Kanto chemical Co., Ltd.) and sufficiently stirring, followed by sterilizing with an autoclave.

Next, the cap of the sample bottle was tightened, and an elution method was performed by a vortex mixer (TX-3000L, manufactured by AS ONE corporation) in an elution method (JIS L1902: 2015: appendix B). In this washing method, the lower part of the sample bottle is pressed against a flat plate or a rubber holding part, and 5 cycles of vibration are performed for 5 seconds.

When the antimicrobial activity value of the antimicrobial paper used as a component in absorbent articles such as disposable diapers and various products on the market is measured, the measurement can be performed by the following method. The hot-melt adhesive is deactivated by using a dryer or a cold sprayer, and other constituent members of the product are carefully removed to obtain the antibacterial paper as the object of measurement. The antibacterial paper thus obtained can be measured for its antibacterial activity value by the bacterial liquid absorption method of "method for testing antibacterial property and antibacterial effect of fiber product" described above. This method of taking out the antibacterial paper is also common to the other measurements in this specification.

The content of the antibacterial agent in the antibacterial paper can be determined according to the antibacterial paperThe purpose of (b) and the like are appropriately set so that a predetermined antibacterial performance can be exhibited. From the viewpoint of achieving the lower limit or more of the antibacterial activity value, the content of the antibacterial agent in the antibacterial paper of the present invention is preferably 0.001g/m in terms of mass per unit area (mass per unit area)²Above, more preferably 0.01g/m²The above. In general, the higher the content of the antibacterial agent, the more the antibacterial performance is improved.

In addition, the content of the antibacterial agent in the antibacterial paper of the present invention is preferably 0.2g/m from the viewpoint of irritation to the skin and permeability of excrement such as urine²Hereinafter, more preferably 0.1g/m²The following. In particular, when the antibacterial paper is used as a component of an absorbent article, the upper limit is preferably not more than the above range from the viewpoint of irritation to the skin and permeability to excrement such as urine.

The calcium content in the antibacterial paper of the present invention is 500ppm or more per 0.1g of the antibacterial paper. The present inventors have found that the calcium content in paper is an index of the softness of the paper, and that the more the calcium content is, the higher the softness of the paper is.

If the calcium content is 500ppm or more per 0.1g of the antibacterial paper, for example, when the antibacterial paper is used as a core-covering sheet covering the absorbent core, the absorbent core is deformed by body pressure or the like, or when excrement such as urine is absorbed and swollen, the antibacterial paper as the core-covering sheet is elongated or deformed following the deformation or swelling of the absorbent core, and therefore, troubles such as breaking of the core-covering sheet are not likely to occur.

The calcium content of the antibacterial paper of the present invention per 0.1g is preferably 510ppm or more, and more preferably 515ppm or more, from the viewpoint of improving flexibility.

On the other hand, from the viewpoint of maintaining hydrogen bonds between constituent fibers such as cellulose fibers in the antibacterial paper and ensuring paper strength, the upper limit of the calcium content in 0.1g of the antibacterial paper of the present invention is preferably 800ppm or less, more preferably 750ppm or less, and still more preferably 700ppm or less.

The calcium content of the antibacterial paper per 0.1g is set to 500ppm or more, and when the antibacterial paper is produced by a conventionally known wet papermaking method, it can be achieved by using high-hardness water that is not generally used as papermaking water for wet papermaking, and this aspect will be described later.

The calcium content in the antibacterial paper was measured by the following method.

< method for measuring calcium content in paper >

A beaker (manufactured by AS ONE Co., Ltd.) made of Teflon (registered trademark) and a petri dish made of Teflon (registered trademark) were immersed in a nitric acid bath and left to stand for 1 day or more. Thereafter, the beaker and the petri dish were taken out from the nitric acid tank, washed with ultrapure water, and then dried. In addition to this operation, the paper to be measured was cut into 5mm squares with ceramic scissors to obtain small pieces. Before use, the scissors are simply cleaned by ethanol and water in advance, and then water is wiped off. 0.1g of the chips obtained were weighed out using a balance and the results were recorded to 4 decimal places. The weighed small pieces were dispensed into washed beakers for accurate weighing. Then, 30mL of hydrochloric acid (manufactured by Kanto chemical Co., Ltd.: for atomic absorption analysis) and 10mL of nitric acid (manufactured by Kanto chemical Co., Ltd.: for atomic absorption analysis) were poured into a beaker. Then, the upper opening of the beaker is covered with a cleaned watch glass, and the beaker is heated for 3 hours by a heating plate provided under the beaker at a temperature of 200 to 250 ℃. During the heating treatment, the decomposition of the content of the beaker was observed and nitric acid was added as appropriate. After heat treatment, the petri dish was removed and the contents concentrated to 10 mL. After concentration, the beaker was removed from the hot plate, allowed to stand for cooling, and 2mL of nitric acid was added to the contents of the beaker. The inside of the watch glass was rinsed with a small amount of ultrapure water (manufactured by Fuji photo film and Wako pure chemical industries, Ltd.), and the ultrapure water for rinsing was poured into a beaker. The contents of the beaker were transferred to a 50mL digestion tube (Digitubes) rinsed with ultrapure water. The inside of the beaker after the transfer of the contents was rinsed with a small amount of ultrapure water, and the ultrapure water for rinsing was transferred to a 50mL digestion tube. The content (aqueous solution) in the 50mL digestion tube was made up to 50mL, and the content was set as a test solution. Calcium in the test solution was quantified by an ICP-MS (Agilent Technologies Co. Ltd.: inductively coupled plasma mass spectrometer) apparatus.

The antibacterial paper of the present invention preferably has a bending rigidity value of 30cN or less, more preferably 29cN or less. The smaller the value of the bending rigidity value, the more excellent the flexibility of the antibacterial paper is, and the easier the bending is.

The antimicrobial paper of the present invention has a bending rigidity value of 25cN or more in practice.

The method of measuring the flexural rigidity value will be described later.

The antibacterial paper of the present invention is typically mainly composed of fibers. The content of the fibers in the antibacterial paper of the present invention is at least 50 mass% or more, preferably 80 mass% or more, and more preferably 90 mass% or more, with respect to the total mass of the antibacterial paper.

In addition, the content of the fiber in the antibacterial paper of the present invention is less than 100 mass%.

The antibacterial paper of the present invention contains at least an antibacterial agent in addition to the fibers, and may contain other components. As the other components other than the fiber and the antibacterial agent that can be contained in the antibacterial paper of the present invention, various components generally used in wet papermaking can be mentioned, for example, paper strength enhancers, fillers, dyes, pigments, pH adjusters, yield improvers, water resistance improvers, defoaming agents and the like can be mentioned, and 1 of these can be used alone or 2 or more can be used in combination.

The antibacterial paper of the present invention is typically mainly composed of cellulose fibers. As the cellulose fiber, cellulose fibers that can be used as a raw material of paper can be used without particular limitation, and examples thereof include: natural fibers such as wood pulp such as softwood pulp and hardwood pulp, and non-wood pulp such as cotton pulp and hemp pulp; modified pulp such as cationized pulp and mercerized pulp; regenerated fibers such as cuprammonium fibers and rayon may be used alone or in combination of 2 or more.

The freeness of the cellulose fiber used in the present invention is not particularly limited, and is preferably 500mL or more, and more preferably 600mL or more, from the viewpoint of the balance between the strength and liquid permeability of the antibacterial paper.

The freeness of the cellulose fiber used in the present invention is preferably 700mL or less, and more preferably 680mL or less.

The Freeness is a value represented by Canadian Standard Freeness (c.s.f., Canadian Standard Freeness) specified in JIS P8121, and is a value representing the degree of beating (a process in which fibers are mechanically beaten and ground in the presence of water) of the fibers. The smaller the value of freeness, the stronger the degree of beating, and the greater the damage to the fibers caused by beating, the more advanced the fibrillation. The beating of the fibers can be carried out by a conventional method using a known beater such as a beater or a disc refiner, and a paper stock (stock) obtained by dispersing the fibers is used.

The antibacterial paper of the present invention may contain other fibers in addition to the cellulose fibers. Examples of the other fibers include heat-fusible fibers. As the heat-fusible fibers, fibers that are bonded to each other by melting under heat can be used. Specific examples of the heat-fusible fibers include: polyolefins such as polyethylene, polypropylene, and polyvinyl alcohol, polyester fibers, polyethylene-polypropylene composite fibers, polyethylene-polyester composite fibers, low-melting polyester-polyester composite fibers, polyvinyl alcohol-polypropylene composite fibers in which the fiber surface is hydrophilic, and polyvinyl alcohol-polyester composite fibers. When the composite fiber is used, either of the core-sheath composite fiber and the side-by-side composite fiber can be used. These heat-fusible fibers may be used alone in 1 kind or in combination of 2 or more kinds.

Typically, the antibacterial paper of the present invention is configured to include a base material mainly composed of fibers, and the base material contains an antibacterial agent. The substrate may have a single-layer structure or a laminated structure in which 2 or more layers are laminated. Another embodiment of the antibacterial paper of the present invention includes an embodiment including a base material and a coating layer laminated on one or both surfaces of the base material, and the coating layer may contain an antibacterial agent.

The mass per unit area of the antibacterial paper of the present invention is not particularly limited, and may be appropriately set according to the use of the antibacterial paper, and the like.

For example, the antibacterial paper (the substrate) preferably has a mass per unit area of 10g/m in terms of balance between strength, liquid permeability, flexibility, and the like²Above, more preferably 12g/m²The above.

From the same viewpoint, it is preferably 50g/m²Hereinafter, more preferably 35g/m²The following.

When the antibacterial paper of the present invention is applied to a component member of an absorbent article or to a core sheet covering the outer surface of an absorbent core, the above range is preferable from the viewpoint of balance with various properties such as liquid permeability.

The antibacterial paper of the present invention is particularly useful as a component of an absorbent article. The present invention includes an absorbent article having the above-described antibacterial paper of the present invention.

The absorbent article of the present invention typically includes a topsheet forming the skin-facing surface, a backsheet forming the non-skin-facing surface, and a liquid-retentive absorbent member disposed between the two sheets.

The topsheet is typically liquid permeable.

The back sheet typically has liquid impermeability or hydrophobicity, but may also have liquid permeability.

The absorbent typically includes an absorbent core and a core-wrapped sheet covering the absorbent core.

The antibacterial paper of the present invention is particularly effective as a core-spun sheet, and is therefore preferable.

The "skin-facing surface" is a surface of the absorbent article or a component thereof (e.g., absorbent core) that faces the skin side of the wearer when the absorbent article is worn, i.e., a surface that is relatively close to the skin of the wearer, and the "non-skin-facing surface" is a surface of the absorbent article or a component thereof that faces the skin side of the wearer when the absorbent article is worn, i.e., a surface that faces a surface that is relatively far from the skin of the wearer.

The front sheet, the back sheet and the absorbent core are each used without particular limitation in the absorbent article of the type generally used in the absorbent article.

The absorbent article of the present invention broadly includes articles for absorbing body fluids (urine, loose stools, menstrual blood, sweat, etc.) discharged from the human body, and includes, for example, disposable diapers, menstrual sanitary napkins, menstrual shorts, incontinence pads, etc.

In the case where the core-covering sheet is the antibacterial paper of the present invention, as one embodiment of the absorbent article of the present invention, the core-covering sheet (the antibacterial paper of the present invention) preferably covers at least the skin-facing surface and the non-skin-facing surface of the absorbent core.

In another embodiment of the absorbent article of the present invention, the absorbent article further includes an intermediate sheet (sub-layer) interposed between the topsheet and the absorbent body, and the intermediate sheet includes the antibacterial paper of the present invention.

The absorbent article of the present invention can be manufactured in the same manner as the absorbent article of this type, and specifically, for example, can be manufactured by combining various members such as a front sheet, a back sheet, an absorbent body (absorbent core, core-wrapped sheet), and an intermediate sheet according to a conventional method.

Typically, the method for producing an absorbent article of the present invention includes a step of combining the antibacterial paper of the present invention with 1 or 2 or more kinds of other members (intermediate products for producing the absorbent article) other than the antibacterial paper.

In the case where the antibacterial paper of the present invention is used as the core-covering sheet as one embodiment of the method for producing an absorbent article of the present invention, a production method having a step of laminating the core-covering sheet with the absorbent core, the front sheet, and the back sheet is exemplified. The core sheet laminating step can be carried out, for example, by obtaining an absorbent body by covering the absorbent core with the core sheet, and disposing the absorbent body between the front sheet and the back sheet.

Next, a method for producing the antibacterial paper of the present invention (hereinafter, also simply referred to as "production method") will be described. The antibacterial paper of the present invention can be produced by the production method of the present invention. The following method for producing the antibacterial paper of the present invention will be described mainly with respect to the aspects not mentioned in the description of the antibacterial paper of the present invention. The above description of the antibacterial paper of the present invention can be applied to the production method of the present invention unless otherwise specified.

The production method of the present invention preferably includes a papermaking step of forming a wet paper web by wet papermaking, and further includes an antimicrobial agent application step of applying an antimicrobial agent-containing liquid to the wet paper web. Preferably, the method further includes a drying step of heating and drying the wet paper having passed through the antimicrobial agent application step.

The production method of the present invention can be carried out according to a conventional method using a known wet paper machine. A wet paper machine typically includes: a pulp preparation section for preparing a pulp, a forming section for continuously forming a wet paper web from the pulp using a paper web, a drying section for heating and drying the wet paper web, and a winding section for winding the paper web (antibacterial paper web) dried by heating into a roll. The papermaking step can be performed by a slurry preparation section and a forming section. The drying step may be performed by a drying section. The drying section of a wet paper machine includes a heating and drying device such as a yankee dryer.

The papermaking step typically includes a step of preparing a slurry (an aqueous dispersion of fibers) containing fibers, and a step of forming a wet paper web on the surface of a papermaking wire by lifting solid components in the slurry with the papermaking wire. The slurry may contain, if necessary, papermaking raw materials usually used in wet papermaking, such as paper strength enhancers and fillers. The solid content concentration of the slurry is usually about 0.005 to 0.2 mass%. The paper making step can be carried out by a conventional method using a conventionally known wet paper machine.

In the papermaking step, the wet paper is formed by using papermaking water having a German hardness of 5 DEG dH or more. That is, for example, when the production method of the present invention is carried out using a typical wet paper machine, water having a german hardness of 5 ° dH or more is used as water (papermaking water) used in at least both the slurry preparation section and the forming section. As described above, the German hardness of the papermaking water generally used in the papermaking plant is 2 to 4.5 DEG dH. In addition, the use of water with a high german hardness tends to be avoided in general. That is, the manufacturing method of the present invention is a manufacturing method for forming a wet paper using water having higher hardness than usual. By forming the wet paper using water having a german hardness of 5 ° dH or more, the calcium content in the antibacterial paper as a production target is easily increased, and thus, the flexibility of the antibacterial paper can be improved as described above. The german hardness of the papermaking water used in the papermaking step is preferably 5.5 ° dH or more, and more preferably 6 ° dH or more.

On the other hand, the upper limit of the german hardness of the papermaking water used in the papermaking step is preferably 12 ° dH or less, more preferably 10 ° dH or less, and even more preferably 8 ° dH or less, from the viewpoint of controlling the calcium content in the antibacterial paper to an appropriate range and maintaining hydrogen bonds between constituent fibers such as cellulose fibers in the antibacterial paper to ensure paper strength.

In the present invention, the German hardness is used as an index of the water hardness. The german hardness (° dH) in the present specification means a hardness in accordance with JIS K0101: 1998 Industrial Water test method 15.1.2 flame atomic absorption method, the concentrations of calcium and magnesium in water were measured, and the results were obtained by using the following calculation formula.

H(mgCaO/100mL)＝{(1.399×C_Ca)+(2.307×C_Mg)}/10

H: german hardness

C_Ca: calcium concentration (mgCa/L)

1.399: coefficient (56.08/40.08) when the amount of calcium is converted into an amount corresponding to that of calcium oxide

C_Mg: magnesium concentration (mgMg/L)

2.307: coefficient (56.08/24.305) when the amount of magnesium was converted into the amount corresponding to the amount of calcium oxide

In the antibacterial agent application step, an antibacterial agent-containing liquid is applied to the wet paper web formed in the paper making step.

The method of applying the antimicrobial agent-containing liquid to the wet paper is not particularly limited, and examples thereof include spraying with a sprayer (non-contact application method) and application with a known application apparatus (contact application method).

The time point for applying the antibacterial agent-containing liquid may be immediately after the wet paper is formed, that is, immediately after the slurry is collected by the paper-making wire. Typically, the antimicrobial-containing liquid is applied after the wet paper is dewatered by pressing.

A typical wet paper machine includes a press device such as a press roll for press-dewatering a wet paper web between a paper web and a heating and drying device constituting a drying section. The wet paper web has a water content of usually about 20 to 85 mass% immediately before the liquid containing the antibacterial agent is applied.

The antimicrobial agent-containing solution is prepared by diluting an antimicrobial agent (preferably a cationic antimicrobial agent) with water. The antimicrobial agent-containing liquid may contain other components than the antimicrobial agent and water as necessary, and typically contains only the antimicrobial agent and water.

The content of the antibacterial agent in the antibacterial agent-containing liquid is not particularly limited, but is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more, based on the total mass of the antibacterial agent-containing liquid.

The content of the antibacterial agent in the antibacterial agent-containing solution is preferably 5% by mass or less, and more preferably 2% by mass or less.

In the production method of the present invention, "dilution water" which is water used for the preparation of the antimicrobial-containing liquid (dilution of the antimicrobial agent) may be different from "papermaking water" which is water used in the papermaking step, in the german hardness. More specifically, in the production method of the present invention, the german hardness of the dilution water is not more than the german hardness of the papermaking water, and is preferably less than the german hardness of the papermaking water.

The reason why "the german hardness of the diluting water is not more than the german hardness of the papermaking water" and preferably "the german hardness of the diluting water < the german hardness of the papermaking water" is as described above, that is, the reason why the antibacterial paper having both the antibacterial property and the flexibility at a high level is obtained. Thus, the antibacterial agent does not react with metal ions contained in the dilution water, and the amount of the antibacterial agent required for expressing a specific antibacterial performance is surely given to the antibacterial paper as a production target. In wet papermaking, it is common technical knowledge to use the same water in a series of steps (including the steps of preparing a slurry and forming and drying a wet paper), and it is considered extremely rare to use water having different hardness in each step as in the present invention.

From the viewpoint of further reliably exhibiting the above-described effects, the german hardness of the dilution water is preferably 4 ° dH or less, more preferably 3 ° dH or less, and most preferably 0 ° dH, that is, 0 ° dH or more, on the assumption that it is equal to or less than the german hardness of the papermaking water as described above.

From the same viewpoint, the ratio of the german hardness of the diluting water to the german hardness of the papermaking water is, for example, preferably 0.7 or less, more preferably 0.5 or less, and most preferably 0, that is, 0 or more, as expressed in terms of the german hardness of the diluting water/the german hardness of the papermaking water, on the premise that "the german hardness of the diluting water is not more than the german hardness of the papermaking water" as described above.

Examples

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples at all.

Production examples 1 to 14 and comparative production examples 1 to 7

Fibers (needle-leaved tree sun-dried kraft pulp, NBKP) were dispersed in water to obtain a slurry, which was put into a beater, and the freeness of NBKP was adjusted to 650 mL. Then, PAE (product name "WS 4030" manufactured by starlight PMC) as a wet paper strength agent was charged into the slurry in an amount of 0.5 mass% based on the dry mass of all fibers in the slurry. The mixture was sufficiently stirred to homogenize the components, thereby preparing a slurry having a solid content concentration of 0.2 mass%. After 10L of water for papermaking was added to a square sheet machine (250mm square, manufactured by Setaria Uralensis Mill Co., Ltd.), the slurry was charged and papermaking was carried out to prepare a wet paper. A filter paper (size 28X 28cm) was placed on the wet paper web, and the water content was adjusted to 75 mass%. Next, the wet paper spray was sprayed with the antimicrobial agent, and then dried using a rotary dryer (manufactured by kusho processor co., ltd.) to produce antimicrobial paper containing the antimicrobial agent.

In the wet papermaking, 1 type of water (papermaking water) having a specific german hardness was used from the preparation of the slurry to the formation of the wet paper. The wet paper web is sprayed with the antimicrobial agent-containing liquid using diluting water by a sprayer, thereby imparting the antimicrobial agent-containing liquid to the wet paper web. The moisture content of the wet paper web immediately before the antimicrobial-containing liquid was applied was 75 mass%. In additionIn addition, in the wet papermaking, the papermaking conditions are appropriately set so that the mass per unit area in a dry state of the paper produced without spraying the antimicrobial-containing liquid is 16g/m². With respect to the content of the antibacterial agent, the antibacterial agent A was 0.01g/m²The antibacterial agent B is 0.0075g/m². The following antimicrobial agent-containing liquid 1 or 2 was used as the antimicrobial agent-containing liquid.

(Water for papermaking)

The german hardness of the papermaking water used is shown in tables 1 and 2 below. The papermaking water with the German hardness of more than 1 DEG dH is prepared by dissolving calcium chloride and magnesium chloride in deionized water, and the content mass ratio of calcium ions to magnesium ions (calcium ions: magnesium ions) is 7: 3, or a salt thereof.

(Water for dilution)

The german hardness of the diluting water used is shown in tables 1 and 2 below. As the water for dilution having a german hardness of 0 ° dH, only deionized water was used. The water for dilution with German hardness of more than 1 DEG dH is prepared by dissolving calcium chloride and magnesium chloride in deionized water, and the mass ratio of calcium ions to magnesium ions (calcium ions: magnesium ions) is 7: 3, or a salt thereof.

(antimicrobial agent-containing solution 1)

Composition: the antibacterial agent a/tromethamine/citric acid/water (water for dilution) was diluted 10 times at 3/0.7/0.3/96, and the concentration of the antibacterial agent in the antibacterial agent-containing solution was 0.3%.

Antimicrobial agent a: cationic antibacterial agent (benzalkonium cetyl phosphate), product name "Sanisol P-2" available from Kao corporation "

Tromethamine: manufactured by Angus Chemical, trade name: TRIS AMINO ULTRA PC tromethamine

Citric acid: purified citric acid (anhydride) product name manufactured by Hibiscus chemical industries, Ltd "

(antimicrobial agent-containing liquid 2)

Composition: the antimicrobial agent B/water (water for dilution) was 3/97, that is, the antimicrobial agent concentration in the antimicrobial agent-containing solution was 3%.

Antimicrobial agent B: cationic antibacterial agent (benzalkonium chloride), product name "Sanisol B-50" available from Kao corporation "

The paper of comparative example 1 was obtained in the same manner as in the above-described production process, except that the antimicrobial-containing solution was not sprayed.

The calcium content and the antimicrobial activity of the antimicrobial papers (examples 1 to 17 and comparative examples 1 to 4) obtained in the production examples and comparative examples were measured by the methods described above, and the flexural rigidity was measured by the following methods. The results are shown in tables 1 and 2.

< method for measuring flexural rigidity value >

The measurement was carried out using a Handle-O-Meter tester manufactured by Daorhiki Seisakusho Seiki Seisakusho, which was suitable for the measurement of stiffness and softness defined in JIS L1096 (general Fabric test method). A test piece having a length of 250mm X250 mm was prepared. The slit interval of the sample table of the testing machine was adjusted to 10mm, and the test piece was disposed so that the center of 2 test pieces was positioned at the center between the slits and the test piece was horizontal, and four corners of the test piece were fixed to the upper surface of the sample table with adhesive tapes. The blade adjusted to a position (lowermost position) lowered from the upper surface of the sample stage to 7mm below was lowered from above the test piece at a fixed speed of 200mm/min, and the highest value (cN) indicated by an indicator (load cell) when the blade pressed the test piece was read. This measurement was performed 5 times and the average value thereof was calculated as the bending rigidity value of the paper. The measurement was carried out at room temperature 23. + -. 2 ℃ and relative humidity 50% RH. + -. 5%.

[ Table 1]

[ Table 2]

TABLE 2

As shown in tables 1 and 2, in the examples and comparative examples, 4 types of paper-making water having german hardness of 4, 6, 8, and 12 were used, and as a result, the content of calcium in the antibacterial paper as a result of production increased as the german hardness of the dilution water increased, and as a result, the bending stiffness value of the antibacterial paper decreased, that is, the flexibility was improved.

The antibacterial paper of the examples was stably provided with antibacterial properties and softness as compared with the antibacterial paper obtained in comparative production examples 1 to 3 (antibacterial paper of comparative examples 1 to 3) and the antibacterial paper obtained in example 1 (antibacterial paper of comparative example 4).

In addition, the production examples can stably produce soft antibacterial paper having antibacterial properties, compared with the antibacterial paper obtained in comparative production examples 1 to 5 (the antibacterial paper of comparative examples 1 to 3 and examples 1 to 2) using paper-making water having a german hardness of 4 ° dH and the antibacterial paper obtained in comparative production example 6 using paper-making water having a german hardness of 8 ° dH and dilution water having a german hardness of 12 ° dH. Focusing on the antibacterial activity value, it is found that when the german hardness of the papermaking water is fixed, and the german hardness of the dilution water is smaller than that of the papermaking water, the antibacterial activity value is high and the antibacterial performance is excellent. From the above, it is understood that soft antibacterial paper having antibacterial properties can be stably produced when 1) the water for papermaking having a german hardness of 5 ° dH or more is used and 2) the german hardness of the dilution water is equal to or less than the german hardness of the water for papermaking. As for the above 2), it is considered that the german hardness of the dilution water is more preferably smaller than that of the papermaking water.

Industrial applicability

The antibacterial paper has antibacterial performance and is soft. In addition, according to the method for manufacturing the antibacterial paper of the present invention, the high-quality antibacterial paper can be efficiently manufactured.