JP6684590B2 - Laminated wet sheet - Google Patents

Description

  The present invention relates to a wet sheet containing a chemical solution, which can be suitably used for cleaning a human body or animals such as pets.

  BACKGROUND ART Wet sheets containing a drug solution are used to wipe off stains on human bodies and animals such as pets (Patent Documents 1 and 2). In particular, for use in wiping baby's buttocks, a wet sheet that is not only high in softness, wipeability and deodorant performance but also safe and less irritating is desired. Therefore, as the chemical liquid, a liquid containing a small amount of an irritating chemical agent (preservative or the like) is required.

JP, 2003-20597, A JP, 2003-79530, A

However, in the case of the conventional wet sheet, there is a problem that if the addition amount of the chemical agent in the chemical solution is reduced, the antibacterial / deodorant effect of the chemical agent and the long-term storage stability of the chemical solution decrease.
If the proportion of chemicals in the chemical solution is increased to improve the antibacterial / deodorant effect, the tactile feel of the wet sheet may be deteriorated as a problem other than safety.
Therefore, it is an object of the present invention to provide a laminated wet sheet which is less irritating and has an improved antibacterial / deodorant effect while having improved wiping properties and touch.

In order to solve the above problems, the laminated wet sheet of the present invention has Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn for the oxidized cellulose fiber having a carboxyl group or a carboxylate group on the surface. And a paper sheet containing metal ion-containing cellulose fibers containing ions of one or more metal elements selected from the group of Cu and Cu, and laminated on the front and back sides of the paper sheet, respectively. Hydrophilic fiber 50-85 mass%, a fiber web comprising a heat-adhesive fiber 15-50 mass%, a laminated wet sheet having, wherein the content of the ion of the metal element to the oxidized cellulose fiber is 10 to 60 mg. / g, a chemical liquid containing 99% by mass or more of water is contained in an amount of 250 to 400% by mass based on the laminated wet sheet.

  According to this laminated wet sheet, since the metal ion-containing cellulose fiber itself in the papermaking sheet has antibacterial / deodorant performance, it is possible to reduce the amounts of preservatives and deodorants in the chemical solution. As a result, the amount of the drug remaining on the surface to be wiped (skin / mucous membrane of human body or animal) is reduced, and irritation can be reduced. Further, the content ratio of water can be increased to 99% by mass or more by reducing the amounts of preservatives and deodorants in the chemical liquid, and loose stools and the like can be wiped off cleanly. If 99.9% by mass or more of water is contained in the chemical liquid, loose stool etc. can be wiped off more easily.

The papermaking sheet preferably contains 2 to 30 mass% of the metal ion-containing cellulose fiber .
It is preferable that the basis weight of the laminated wet sheet is 30 to 100 gsm and the basis weight of the papermaking sheet is 30 to 50% by mass of the entire laminated wet sheet.
The chemical solution preferably contains water in an amount of 99.9% by mass or more.

  According to the present invention, it is possible to obtain a laminated wet sheet which is less irritating and secures an antibacterial / deodorant effect while improving wiping property and touch.

It is a figure which shows the transmission electron microscope image of the metal ion containing cellulose fiber used for the Example.

  The laminated wet sheet according to the embodiment of the present invention has a laminated structure including a papermaking sheet described below and fibrous webs laminated on the front and back sides of the papermaking sheet, and contains a chemical solution.

<Papermaking sheet>
The papermaking sheet contains at least one kind selected from the group consisting of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn and Cu for the oxidized cellulose fiber having a carboxyl group or a carboxylate group on the surface. A metal ion-containing cellulose fiber containing ions of a metal element and a pulp fiber are included. The "papermaking sheet" means a sheet made of pulp fibers by a papermaking method, and is a papermaking sheet in a state where pulp fibers are intertwined with each other by a microscope.

  This metal ion-containing cellulose fiber can be obtained by bringing an aqueous metal compound solution into contact with the oxidized cellulose fiber having a carboxyl group or a carboxylate group introduced on the surface of the cellulose fiber. Further, as a method for producing a wet sheet according to an embodiment of the present invention, other than the method of contacting the metal compound aqueous solution with a sheet made of a raw material containing oxidized cellulose fibers, preliminarily containing metal ions in the oxidized cellulose fibers, A method for producing a raw material containing this metal ion-containing cellulose fiber can be exemplified.

The oxidized cellulose fibers can be produced by oxidizing cellulose fibers such as wood pulp using an N-oxyl compound as a catalyst. By this oxidation reaction, the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized, and an oxidized cellulose fiber having a carboxyl group or a carboxylate group on the surface is obtained. The raw material cellulose is preferably natural cellulose. The oxidation reaction is preferably performed in water. The concentration of cellulose fibers in the reaction is not particularly limited, but is preferably 5% by mass or less. The amount of the N-oxyl compound may be about 0.1 to 4 mmol / L with respect to the reaction system. A known co-oxidant may be used in the reaction. Examples of the co-oxidant include dihalous acid or a salt thereof. The amount of the co-oxidant is preferably 1 to 40 mol with respect to 1 mol of the N-oxyl compound.
The reaction temperature is preferably 4 to 40 ° C, more preferably room temperature. The pH of the reaction system is preferably 8-11. The degree of oxidation can be appropriately adjusted by the reaction time, the amount of N-oxyl compound and the like.
The thus-obtained oxidized cellulose fiber has acid groups on its surface and almost no acid groups inside. It is considered that this is because the cellulose fiber is crystalline, and thus the oxidant does not easily diffuse into the inside of the fiber.

The carboxyl group means a group represented by -COOH, and the carboxylate group means a group represented by -COO-. The counter ion of the carboxylate group when producing the oxidized cellulose fiber is not particularly limited. Then, the metal ion described below replaces the counter ion and ionically bonds with the carboxylate group. Further, the carboxyl group seems to coordinate with copper ion as a metal ion. The carboxyl group or the carboxylate group is collectively referred to as "acid group".
The content of the acid group can be measured by the method disclosed in paragraph 0021 of JP-A-2008-001728. That is, 60 mL of a 0.5 to 1 mass% slurry is prepared using a precisely weighed dry cellulose sample, and the pH is adjusted to about 2.5 with a 0.1 mol / L hydrochloric acid aqueous solution. Then, 0.05 mol / L sodium hydroxide aqueous solution is dropped to measure the electric conductivity. The measurement is continued until the pH is about 11. From the amount (V) of sodium hydroxide consumed up to the neutralization stage of a weak acid with a gradual change in electrical conductivity, the acid group amount X1 is calculated using the following formula.
X1 (mmol / g) = V (mL) × 0.05 / mass of cellulose (g)

  The amount of acid groups in the cellulose fiber is preferably 0.2 to 2.2 mmol / g. If the amount of acid groups is less than 0.2 mmol / g, the amount of metal ions present on the surface of the cellulose fiber may be insufficient and the deodorizing function may be poor. If the amount of the acid groups exceeds 2.2 mmol / g, the drainage during the papermaking of the wet sheet may be deteriorated and the dehydration load may be increased.

Next, the aqueous solution containing the compound of the metal is brought into contact with the oxidized cellulose fiber, and the metal ion derived from the metal compound forms an ionic bond with the carboxylate group. The carboxyl group is considered to ionize and ionically bond with the metal ion via the carboxylate group, or coordinate with the metal ion as described above.
The metal compound aqueous solution is an aqueous solution of a metal salt. Examples of metal salts include complexes (complex ions), halides, nitrates, sulfates, and acetates. The metal salt is preferably water-soluble.
Regarding the method for contacting the metal compound, a dispersion of the cellulose fiber prepared in advance and an aqueous solution of the metal compound may be mixed, and the dispersion containing the cellulose fiber is applied onto a substrate to form a film, and the metal compound is added to the film. You may add and impregnate an aqueous solution. At this time, the film may remain fixed on the substrate or may be separated from the substrate.
The concentration of the aqueous metal compound solution is not particularly limited, but is preferably 10 to 80 parts by mass, and more preferably 30 to 60 parts by mass with respect to 100 parts by mass of the cellulose fiber.
The time for contacting the metal compound may be adjusted appropriately. The temperature at the time of contact is not particularly limited, but 20 to 40 ° C is preferable. Further, the pH of the liquid at the time of contact is not particularly limited, but when the pH is low, it becomes difficult for the metal ion to bond to the carboxyl group, so 7 to 13 is preferable, and pH 8 to 12 is particularly preferable.

The fact that the oxidized cellulose fibers contain (coordinate) the metal ions can be confirmed by a scanning electron microscope image and ICP emission analysis of the extract with a strong acid. That is, the presence of metal ions cannot be confirmed in the scanning electron microscope image, while it can be confirmed that the metal ions are contained in the ICP emission analysis. On the other hand, for example, when the above metal is reduced from ions and exists as metal particles, the metal particles can be confirmed in a scanning electron microscope image or a transmission electron microscope image. You can judge. The presence or absence of metal ions can also be determined by scanning electron microscope images and elemental mapping. That is, although the metal ions cannot be confirmed in the scanning electron microscope image, the existence of the metal ions can be confirmed by performing the element mapping.
The antibacterial function is imparted by using one or more kinds of ions selected from the group of Ag and Cu as the metal ions. On the other hand, it is not necessary for the metal particles to bind to all the acid groups of the cellulose fiber, and the remaining acid groups can also neutralize odorous components such as ammonia, thus exerting a deodorizing function.

As the pulp fiber, for example, virgin pulp such as softwood pulp (NBKP) or hardwood pulp (LBKP), or used paper pulp recycled from used paper can be used. These pulps are appropriately blended in predetermined types and blending ratios according to the required quality.
Various chemicals may be added (internally added) to the papermaking raw material for the required quality and stable operation. Examples of these chemicals include softening agents, bulking agents, dyes, dispersants, wet paper strengthening agents, and drying agents. Examples include paper strength agents, drainage improvers, pitch control agents, retention improvers, and the like.

The papermaking sheet preferably contains 2 to 30 mass% of metal ion-containing cellulose fibers.
When the compounding ratio of the metal ion-containing cellulose fiber is less than 2% by mass, the antibacterial / deodorant performance due to the metal ion-containing cellulose fiber in the papermaking sheet is reduced, and the amount of the preservative or deodorant in the chemical solution is reduced. Can be difficult.
When the mixing ratio of the metal ion-containing cellulose fiber exceeds 30% by mass, the ratio of the pulp fiber in the papermaking sheet decreases, and it becomes difficult to firmly hold the chemical solution in the papermaking sheet, and the function of wiping loose stool etc. cleanly decreases. I have something to do.

In the metal ion-containing cellulose fiber, the content of metal ion relative to the oxidized cellulose fiber is preferably 10 to 60 mg / g.
If the content of metal ions is less than 10 mg / g, the antibacterial / deodorant performance of the metal ion-containing cellulose fibers in the papermaking sheet will deteriorate, making it difficult to reduce the amount of preservatives and deodorants in the chemical solution. May become.
Producing a metal ion content of more than 60 mg / g leads to a decrease in the yield of the metal ion-containing cellulose fiber, resulting in an increase in cost.

<Fiber web>
The fibrous web is composed of 50 to 85% by mass of hydrophilic fibers and 15 to 50% by mass of heat adhesive fibers. The fibrous web is obtained by a dry card method, in which short fibers having a length of about 15 to 100 mm are intertwined with each other, and the fiber length is completely different from that of the above-mentioned papermaking sheet when viewed under a microscope, so that they can be distinguished from each other.
Examples of hydrophilic fibers include natural fibers such as cotton, viscose rayon, and lyocell fibers.
Examples of the heat-bondable fiber include PE fiber, PE / PP composite fiber, PE / PET composite fiber, and low melting point PET / PET composite fiber.
Further, other fibers may be blended to adjust the texture and the like. Examples of the other fibers include polyester fibers, and the sheet of the fiber web becomes bulky and soft.

<Laminate wet sheet>
The laminated wet sheet has a laminated structure in which a papermaking sheet is interposed between two layers of non-woven fabric, and the non-woven fabric on the surface imparts soft touch. Further, since the papermaking sheet inside has a high water content because it contains pulp fibers, it has a function of firmly holding a chemical solution containing 99% by mass or more of water described later to cleanly wipe loose stools and the like.
In the laminated wet sheet, a papermaking sheet is laminated between two layers of non-woven fabric, and the whole can be integrated by, for example, spunlacing and interlacing the fibers of each layer with a high-pressure water stream.

<Medicinal solution>
The chemical liquid contains 99% by mass or more of water in the chemical liquid. Since the metal ion-containing cellulose fibers themselves in the papermaking sheet have antibacterial / deodorant properties, the amounts of preservatives and deodorants in the chemical liquid can be reduced. As a result, the amount of the drug remaining on the surface to be wiped (skin / mucous membrane of human body or animal) is reduced, and irritation can be reduced. Further, the content ratio of water can be increased to 99% by mass or more by reducing the amount of the preservative and the deodorant in the liquid medicine, and as described above, loose feces can be wiped off cleanly. If 99.9% by mass or more of water is contained in the chemical liquid, loose stool etc. can be wiped off more easily.
The chemical solution may contain a preservative and a deodorant. The preservative mainly imparts long-term storage stability of the chemical liquid, and the deodorant imparts antibacterial / deodorant effect.
Since the metal ion-containing cellulose fibers themselves in the papermaking sheet have antibacterial / deodorant performance, it is preferable that the chemical solution does not contain a deodorant and that the preservative is contained in the chemical solution in an amount of 0.1% by mass or less.
As preservatives, benzalkonium chloride; paraoxybenzoic acid ester and its sodium salt; benzoic acid and its salts; sorbic acid and its salts; dehydroacetic acid and its salts; phenoxyethanol, phenol, resorcin, benzoic acid pantothenyl ethyl ether , Isopropylmethiphenol, cetylpyridinium chloride, chlorhexidine hydrochloride, orthophenylphenol, chlorhexidine gluconate, chlorxylenol, chlorhexidine, alkylisokyrrolinium bromide, thymol, trichlorocarbanilide, halocarban, hinokitiol, polyaminopropyl biguanide, etc. Can be mentioned.

<Amount of chemical>
The chemical solution is contained in an amount of 250 to 400 mass% with respect to the laminated wet sheet. The amount (mass%) of the chemical liquid is calculated by (wet mass−dry mass) / dry mass × 100 of the laminated wet sheet.
When the content of the chemical liquid is less than 250% by mass with respect to the laminated wet sheet, the amount of water in the chemical liquid is small and the function of wiping loose stool or the like cleanly is poor. When the content of the chemical liquid exceeds 400% by mass with respect to the laminated wet sheet, the sheet contains too much water and becomes difficult to handle.
It is preferable that the chemical solution is contained in an amount of 280 to 400 mass% with respect to the laminated wet sheet.

The weight of the laminated wet sheet is preferably 30 to 100 gsm, and the weight of the papermaking sheet is preferably 30 to 50% by mass of the entire laminated wet sheet.
When the basis weight of the laminated wet sheet is less than 30 gsm, the strength is lowered, and the amount of water retained per sheet is reduced, which may make it difficult to remove stains. If the basis weight of the laminated wet sheet exceeds 100 gsm, the thickness increases, which may make it difficult to wipe off dirt between fine wrinkles and may lead to an increase in cost.
When the basis weight of the papermaking sheet is less than 30% by mass of the entire laminated wet sheet, the chemical solution may not be sufficiently retained, and it may be difficult to wipe off loose stools cleanly. It may not be possible to obtain a nice touch.
The basis weight is measured by washing the laminated wet sheet with water and then drying it.

  It is needless to say that the present invention is not limited to the above-described embodiments and covers various modifications and equivalents included in the concept and scope of the present invention.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not of course limited to these examples.

<Production of metal ion-containing cellulose fiber>
5.00 g dry weight undried conifer bleached kraft pulp, 39 mg 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and 514 mg sodium bromide were dispersed in 500 ml water, A 15 mass% sodium hypochlorite aqueous solution was added to 1 g of pulp (absolutely dry) so that the amount of sodium hypochlorite was 5.5 mmol to start the reaction. During the reaction, 3M NaOH aqueous solution was added dropwise to keep the pH at 10.0. When no change in pH was observed, the reaction was considered to be complete, and the reaction product was filtered through a glass filter, washed with a sufficient amount of water, and filtered twice to impregnate water with a solid content of 15% by mass. TEMPO oxidized cellulose fiber was obtained.
This TEMPO oxidized cellulose fiber has a carboxyl group or a carboxylate group on its surface. Table 1 shows the acid group amount (per 1 g of oxidized cellulose fiber) of the TEMPO oxidized cellulose fiber before containing the metal ions.

Next, the obtained TEMPO oxidized cellulose fibers (which do not contain metal ions at this point) are defibrated (beating), and the obtained TEMPO oxidized cellulose fibers after beating have the pH and concentration shown in Table 1. An aqueous metal salt solution (per 1 g of TEMPO oxidized cellulose fiber) was added and stirred. Thereby, the TEMPO oxidized cellulose fiber was made to carry the metal ion.
In addition, FIG. 1 shows a transmission electron microscope image of the metal ion-containing cellulose fibers used in the examples.

<Laminate wet sheet>
The metal ion-containing cellulose fiber and pulp (NBKP and LBKP) were blended at a blending ratio shown in Table 2 to prepare a pulp slurry, and a papermaking sheet was manufactured.
Next, the fibers shown in Table 2 were blended to form a fiber web by a dry card method, the fiber web was laminated on the front and back surfaces of the papermaking sheet, and the whole was integrated by spun lace to produce a laminated wet sheet. . Rayon fiber was used as the hydrophilic fiber, and PE / PP composite fiber was used as the heat-bonding fiber. Polyester fiber was used as the other fiber.
<Chemical solution impregnation>
Next, the liquid chemicals having the components shown in Table 2 were impregnated into the dry laminated wet sheet at a ratio shown in Table 2. A green tea extract (epigallocatechin gallate) was used as a deodorant, and a benzalkonium chloride 50% solution was used as a preservative.

  Of the laminated wet sheets of each example, when the papermaking sheet was observed with a scanning electron microscope, only the fibers of the paper were confirmed. Further, with respect to the papermaking sheet of each example, ICP ((high-frequency inductively coupled plasma) emission analysis of the extract after dissolution with a strong acid was performed, and it was confirmed that each contained a metal. It can be seen that the laminated wet sheet papermaking sheets of the respective examples contain oxidized cellulose fibers and metal ions.

The following evaluation was performed on the obtained laminated wet sheet.
<Deodorant>
A saturated gas of aqueous ammonia solution (2 mL of ammonia water: 2 mL of water) was inserted with a 1.2 mL syringe into a gas bag with a cock containing four 5 cm x 5 cm laminated wet sheet test pieces, and 1.5 L of air was further added with an air pump. Filled. The saturated gas was collected from the gas phase of a closed container containing an aqueous ammonia solution. The ammonia gas concentration in the gas bag after filling with saturated gas and air was 80 to 90 ppm. Next, the suction tube and the rubber tube were connected to the detector tube, and the rubber tube was connected to the gas bag. Then, the concentration of ammonia gas in the gas bag 50 minutes after the air was filled was measured and evaluated according to the following criteria.
⊚: Residual concentration was 1/5 or less of the initial value ◯: Residual concentration was more than 1/5 of the initial value and ¼ or less Δ: Residual concentration was more than 1/4 of the initial value and ⅓ or less ×: Residual concentration was the initial value Further, the deodorizing property was evaluated in the same manner after adding purified water at a rate of 5 g per 1 g of the laminated wet sheet test piece to make it wet.
If each evaluation is ◎ or ○, there is no problem in practical use.

<Storage stability>
The laminated wet sheet was packed in a predetermined packaging bag, stored unopened at 40 ° C. for 6 months and then opened, and the presence or absence of bacterial growth on the laminated wet sheet was visually evaluated according to the following criteria.
○: No discoloration or offensive odor due to bacterial growth ×: Discoloration due to bacterial growth or offensive odor etc. <Irritation>
According to the 24-hour human closed patch test, 20 subjects were wiped off their skins with a laminated wet sheet, and the presence or absence of skin irritation was evaluated according to the following criteria.
◯: Negative and pure negative ×: Semi-positive and positive <Wipeability>
The dummy stool was wiped off and evaluated according to the following criteria. The evaluation may be ◯ or Δ.
◯: Very easy to wipe △: Easy to wipe ×: Difficult to wipe <feeling>
It evaluated by the sensory evaluation (n = 20 persons). The evaluation may be ◯ or Δ.
◯: Very good tactile feeling Δ: Good tactile feeling ×: Poor tactile feeling

  The obtained results are shown in Tables 1 and 2.

As is clear from Table 2, in the case of each example, there was little irritation, and the antibacterial / deodorant effect and the tactile sensation were secured.
On the other hand, in Comparative Example 1 in which the metal ion-containing cellulose fiber was not contained in the papermaking sheet, a preservative was added to the chemical solution in an amount of more than 0.1% by mass in order to enhance the antibacterial effect and impart storage stability. As a result, it was inferior in irritation and touch, and was also inferior in deodorant property because it contained no deodorant.
In the case of Comparative Example 2 in which the content of metal ion relative to the oxidized cellulose fiber was less than 10 mg / g and only 0.1% by mass of the preservative was added to the chemical solution, the deodorizing effect of the metal ion-containing cellulose fiber was lowered. In addition, the storage stability was poor due to the small amount of deodorant.
In the case of Comparative Example 3 in which the preservative was not added to the chemical solution, the storage stability was poor.
In addition, in each of the examples in which the chemical liquid contained 99.9% by mass or more of water, the wiping property was further improved as compared with the comparative example.

Claims (4)

Ions of one or more metal elements selected from the group of Ag, Au, Pt, Pd, Ni, Mn, Fe, Ti, Al, Zn and Cu for oxidized cellulose fibers having a carboxyl group or a carboxylate group on the surface. A metal ion-containing cellulose fiber containing, and a papermaking sheet containing pulp fiber,
A laminated wet sheet having a fiber web composed of hydrophilic fibers 50 to 85% by mass and thermal adhesive fibers 15 to 50% by mass, which are laminated on the front and back sides of the papermaking sheet, respectively,
The content of the ions of the metal element with respect to the oxidized cellulose fiber is 10 to 60 mg / g,
A laminated wet sheet containing a chemical solution containing 99% by mass or more of water in an amount of 250 to 400% by mass based on the laminated wet sheet.   The laminated wet sheet according to claim 1, wherein the papermaking sheet contains 2 to 30% by mass of the metal ion-containing cellulose fiber. The laminated wet sheet according to claim 1 or 2, wherein the laminated wet sheet has a basis weight of 30 to 100 gsm, and the papermaking sheet has a basis weight of 30 to 50 mass% of the entire laminated wet sheet. The laminated wet sheet according to claim 1 , wherein the chemical liquid contains 99.9% by mass or more of water .