JP7396927B2 - Sanitary tissue paper and its manufacturing method - Google Patents

Description

The present invention relates to sanitary tissue paper.

Representative examples of this type of sanitary tissue paper are toilet paper and tissue paper.
Flexibility is required for both, but toilet paper is particularly required to have water-disintegrability, and tissue paper is required to have wiping properties.

On the other hand, water-disintegratable wet tissues that are packaged in a wet state impregnated with water are also known (Patent Document 1).

Japanese Patent Application Publication No. 3574318

Even though this prior art has the advantage of being water-disintegrable and can be flushed down the toilet, its technical content basically means that it is the best toilet for use in a flush toilet (with a flushing device). It is used as paper, and as a wet tissue for cleaning the body, such as wiping baby's bottoms, and for wiping work such as cleaning.

However, it is not necessarily suitable for general tissue paper applications, and is not suitable for so-called facial applications such as blowing the nose.

Also, tissue paper coated with an oil-based chemical solution (lotion) is known, but there are still drawbacks such as giving a sticky feeling and leaving oil behind when wiping.

Therefore, the main object of the present invention is to provide a water-disintegrable sanitary tissue paper that is pleasant to the touch, has sufficient strength, and has excellent wipeability, and a method for producing the same.

The present invention to solve this problem is
It is made of 3 or 4 layers of tissue paper,
The basis weight per product is 13.5 to 19.5 g/m ² ,
An oil-based chemical solution containing an oil component of 30% by mass or more is applied at 3.0 to 20.0% by mass,
The present invention provides a sanitary thin paper whose water decomposition according to JIS P 4501 is 100 seconds or less.

On the other hand, when producing such sanitary tissue paper, a pulp containing 30 to 85% by mass of NBKP is used, and a paper stock containing no temporary wet strength enhancer but containing a dry strength enhancer has a Canadian freeness of 300. Provided is a method for producing sanitary tissue paper, which includes a step of obtaining base paper through beating to ~600 CSF.

According to the present invention, a water-disintegrable sanitary tissue paper having sufficient strength and excellent wiping properties and a method for producing the same can be obtained.

It is an evaluation result diagram of a test example. It is an evaluation result diagram of a test example. It is an evaluation result diagram of a test example. It is an evaluation result diagram of a test example. It is an evaluation result diagram of a test example.

Embodiments of the present invention will be described below.

Thin paper can be manufactured by passing papermaking raw materials, mainly raw material pulp, through a known papermaking process, specifically, through a wire part, press part, dryer part, size press, calender part, etc.
When making this paper, appropriate chemicals such as dispersants, pH adjusters such as caustic soda and aqueous ammonia, antifoaming agents, preservatives, fluorescent dyes, mold release agents, water resistance agents, flow modifiers, and retention improvers are used. can be added.

The raw material pulp used as the raw material for papermaking is not particularly limited, and any suitable raw material pulp can be selected and used.
As this raw material pulp, it is desirable to use, for example, kraft pulp (KP) such as hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP).
Particularly, the raw material pulp is preferably a mixture of NBKP and LBKP for the purpose of making it a common product for toilet paper and tissue paper. Waste paper pulp may be blended as appropriate, but from the viewpoint of texture etc., it is better to consist of only NBKP and LBKP, in which case the mass blending ratio is NBKP:LBKP = 30:70 to 85:15. However, particularly preferred is NBKP:LBKP=35:65 to 65:35.

Further, the beating is preferably to a Canadian freeness of 450 to 650 CSF, particularly 500 to 600 CSF.

This is because by using a large amount of strong NBKP, the dry strength of the product can be improved, which is preferable. .

The product according to the present invention is soft and feels good to the touch, and can also be used for wiping dirt off the skin as well as on the surfaces of furniture, equipment, and other items. It is desirable that the product has a high dry strength to avoid this.

For example, it is preferable that the dry strength (longitudinal direction) of the product is 300 to 850 cN/25 mm, particularly 400 to 700 cN/25 mm. Furthermore, the dry strength (lateral direction) is important in relation to the intended use, and is preferably 110 to 400 cN/25 mm, particularly 160 to 250 cN/25 mm.
If the dry strength is low, tears may occur during wiping, and if the dry strength is excessively high, the softness and feel will be reduced.

It is desirable to add a dry strength agent to increase the dry strength of the product. In the present invention, the dry paper strength enhancer is not particularly limited, and examples include carboxymethyl cellulose (CMC), polyacrylamide (PAM), and polyvinyl alcohol (PVA). In particular, it is recommended to use cationized starch and cationic or amphoteric polyacrylamide copolymers.

In addition to applying the dry paper strength agent to the entire three or four sheets, it is preferable to apply it to the intermediate sheet, since a water-based moisturizing chemical is mainly applied to the outer layer sheet. .
The dry paper strength agent is applied to the intermediate sheet by applying, for example, modified starch, polyacrylamide, polyvinyl alcohol (PVA), etc. to one or both outer surfaces of the intermediate sheet in a non-contact manner by roll transfer coating or spraying. (Size press and nip coat methods are not desirable).
For the outer layer sheet, no dry paper strength enhancer is applied, and a small amount of dry paper strength enhancer can be applied to the extent that it does not affect the flexibility or surface properties of the product.

The amount of dry paper strength enhancer applied is desirably 10 to 17 kg/t, particularly 12 to 15 kg/t based on the dry fiber weight of the base paper.
As mentioned above, the applied amount of the dry paper strength agent means the applied amount to one or two intermediate sheets, and not the applied amount to the laminated state.

In order to obtain the desired dry strength of the product, in addition to adding a dry paper strength enhancer and using a large amount of NBKP as pulp, paper stock is prepared after beating to a Canadian freeness of 300 to 600 CSF, especially 350 to 500 CSF. It is desirable to obtain In order to obtain water-disintegrability, it is desirable to obtain a paper stock that does not contain a temporary wet paper strength agent.

By incorporating the above elements, the strong NBKP fibers become entangled with each other and become fibrillated, which strengthens the bond between the fibers. While ensuring good water disintegration, the surface strength of the sanitary tissue paper increases, creating a sanitary tissue paper that is difficult to tear. Obtainable.

As mentioned above, the dry strength agent is applied to the intermediate sheet, and the dry strength agent is not applied to both outer layer sheets, and if it is applied, it may affect the flexibility and surface properties of the product. At the same time, a water-based moisturizing chemical solution is applied to both outer layer sheets without containing a temporary wet paper strength agent. In this way, in order to make the outer layer sheet and the inner layer sheet have different roles, it is necessary to use three or four laminated sheets.

To obtain the base paper (sheet before lamination), softeners (e.g. fatty acid ester compounds, fatty acid amide compounds (surfactants)) and bulking agents (paper thickness is high relative to basis weight) are used. Addition of agents (for example, oil-based or sugar-based nonionic surfactants, higher alcohols, fatty acid ester compounds, polyoxyalkylene adducts, etc.) reduces paper strength. In the present invention, the addition of softeners and bulking agents is limited, and preferably none are added. When added, it is preferably 5 kg/t or less, particularly 1 kg/t or less per absolute dry weight of pulp.

As mentioned above, it is desirable to obtain a stock that is free of temporary wet strength agents in order to obtain water disintegrability. "Temporary wet paper strength enhancer" is a term known to those skilled in the art, and it temporarily prevents paper strength from decreasing due to absorption of moisture, causing problems such as paper breakage and deteriorating operability. In order to maintain the wet strength of the base paper from the application of the wet paper strength agent to the winding process, the wet strength of the base paper is maintained at a constant level during use after it is made into sanitary tissue paper (under large amounts of moisture such as in flush toilets). It is designed to lose its wet strength over time.
Examples of this "temporary wet paper strength agent" include polyamide polyamine resin (PA resin), typified by Kleptorol 190 from Herculis, and polyamide amine epichlorohydrin (PAE resin), typified by Kymen 557H from Herculis. ), cationic polyamide resin, polyvinyl alcohol (PVA), polyamide plasticizer additive, polyamide softener additive, modified polyamide amine, polyvinyl acetate, etc., and these may be used alone or in combination. Further, ARAFIX 255 manufactured by Arakawa Chemical Industry Co., Ltd. can also be used.

"Temporary wet paper strength enhancer" can be added in an amount of 5 kg/t or less, especially 2 kg/t or less of the dry fiber weight of the base paper, but in order to ensure reliable water disintegration, it is preferable not to add it. .

The basis weight per ply of base paper is preferably 13.5 to 19.5 g/m ² , particularly 14.5 to 18.0 g/m ² .
If the basis weight is low, the wipeability etc. will not be sufficient, while if the basis weight is too high, the flexibility and feel will be poor.
It is preferable for the basis weights of each ply of the base paper to be the same in terms of operability and economy, but if necessary, the basis weights can be made to be different within the above-mentioned range.

The base paper unwound from a primary roll (3 or 4 rolls) of non-creped base paper or preferably creped base paper is laminated, contact embossed, and then surface smoothed using a calendar. , 3 or 4 ply laminated base paper can be obtained. The 3 or 4 ply laminated base paper can be wound up as a roll.
In addition, if necessary, in addition to contact embossing, design embossing for the purpose of bulkiness and flexibility can be formed.
Further, the crepe rate is preferably 10 to 30%. The crepe rate is expressed as [((peripheral speed of the dryer during paper making)−(peripheral speed of the reel))/(peripheral speed of the dryer during paper making)]×100.

The paper thickness per ply of the product is preferably 60 to 130 μm, particularly 70 to 110 μm, and more preferably 80 to 100 μm. The reason for the upper and lower limits of the numerical range is the same as the reason for basis weight.

For 3- or 4-ply laminated base paper, the base roll is set in a so-called rotary interfolder, and during the process from unwinding to folding, the laminated sheet is formed by gravure coating, spray coating, etc. using an oil-based chemical as a coating liquid. It can be applied to one or both outer layer surfaces.

By applying an oil-based coating liquid to one or both outer layer surfaces of the laminated sheet, the chemical component content of the resulting product is lower in the intermediate sheet (ply) than in the outer layer sheet.
On the other hand, when an oil-based chemical is applied to only one outer layer surface of a laminated sheet, the chemical component content becomes lower in the order of the outer layer sheet to which the oil-based chemical is applied, the intermediate sheet, and the other outer layer sheet. .

The oil-based coating liquid in the present invention is desirably an oil-based chemical containing an oily component of 30% by mass or more, particularly 38% by mass or more. This oil-based coating liquid is preferably applied to the base paper in an amount of 3.0 to 20.0% by mass, particularly 5.0 to 18.0% by mass.

Oil-based ingredients include, but are not limited to, liquid paraffin, mineral oils such as petrolatum, jojoba oil, argan oil, camellia oil, macadamia nut oil, olive oil, apricot kernel oil, avocado oil, evening primrose oil, and wheat jam. Examples include vegetable oils such as oil, carrot oil, kukui nut oil, grapeseed oil, coconut oil, sweet almond oil, sesame oil, St. John's wort oil, peach kernel oil, hazelnut oil, borage oil, and rosehip oil. Particularly preferred is liquid paraffin.

The amount of effective oily components not containing water in the oil-based drug solution is desirably 25% by mass to 75% by mass, particularly 35% by mass to 65% by mass.

It is preferable to include a water-based chemical solution in an oil-based chemical solution. Typical examples of water-based chemical components are polyols, and glycerin is particularly desirable. The drug solution contains a hygroscopic polyol such as glycerin as a main component, and it contains 18 to 55% by mass, especially 22 to It is desirable to contain 55% by mass.

The oil-based chemical solution can contain 2.0 to 26.0% by mass of functional agents such as surfactants , emulsifiers , softeners, and preservatives.
As the surfactant, for example, an alkyl phosphate ester salt is preferred.

In the production of sanitary tissue paper, a bundle of laminated sheets folded with a rotary interfolder is cut to a predetermined length and packaged as a predetermined number of bundles in a packaging box, or enclosed in a plastic film packaging bag. I can do it. In order to maintain moisture retention, it is desirable to use the latter packaging bag product (so-called film pack product) using plastic film.

Further, the water-disintegrable sanitary tissue paper of the present invention has a water-disintegrability value of 10 to 100 seconds, preferably 25 to 60 seconds. Note that the water-disintegrability here is expressed in seconds in a disintegration test (test of "ease of disentanglement" specified in JIS P 4501). If the water-disintegrability value is less than 10 seconds, there is a high risk that loosened tissue paper will stick to the skin when wiping it when used in a shower toilet, and if it exceeds 100 seconds, when flushed down the toilet, Piping is more likely to become clogged.

Next, we will explain related numerical values and how to measure them.

[Yonetsubo]
On the other hand, the basis weight of each continuous thin paper is the value according to the basis weight measurement method of JIS P 8124.

[Paper thickness]
The paper thickness is measured under the conditions of JIS P 8111 using a dial thickness gauge (thickness measuring instrument) "PEACOCK Model G" (manufactured by Ozaki Seisakusho). Specifically, after confirming that there is no dirt, dust, etc. between the plunger and the measuring table, lower the plunger onto the measuring table, move the memory of the dial thickness gauge to set the zero point, and then , raise the plunger and place the sample (for example, one ply of product) on the test stand, then slowly lower the plunger and read the gauge at that time. At this time, just place the plunger on it. Note that the paper thickness is an average value obtained by performing measurements 10 times.

[Product dry strength]
The dry strength of the product (laminated product) is determined according to the tensile test method of JIS P 8113, and is measured by the number of layers of the product. It shall be cut to a width of 25 mm in the vertical and horizontal directions under the standard conditions specified in JIS P 8111.

[Medicinal liquid component content]
The chemical component content is defined as the denominator (A) (g), which is a tissue paper product of a specified mass that has been humidity-controlled under JIS P 8111 conditions, and the water content in the chemical solution contained in a tissue paper product of a specified mass is excluded. Mass (B) (g) is the numerator, and the ratio of (B) divided by (A) is expressed as (%).
(Medicinal liquid component content%) = (B) ÷ (A) x 100 (%)

When a water-based chemical solution is included in an oil-based chemical solution, the liquid at the application stage can be water-based. The water content in the chemical solution contained in the base paper can be measured by the Karl Fischer method.
Note that the viscosity of the chemical solution during application is preferably 50 to 300 mPa·s. If the chemical solution viscosity is less than 50 mPa·s, the flexibility on the surface will be impaired. If the chemical liquid viscosity exceeds 300 mPa·s, the lotion chemical liquid in the sheet will have difficulty penetrating between the fine fibers, and the planar uniformity and texture will be lost, which is not preferable.

Next, examples, comparative examples, and commercially available products will be shown.
Commercial products A and B are commercially available as so-called moisturizing tissue paper, and commercial product A has a high chemical solution application rate, while commercial product A has a low chemical coating rate. Commercial product C is a common toilet paper.

Sensory evaluation by users was conducted for Examples 1 to 13 and Comparative Examples 1 to 8 in which various elements were changed. The results are shown in Tables 1 to 3.

Regarding the sensory evaluation, 20 test subjects actually used three or four sheets of laminated sanitary tissue paper according to each example for one week, and the results were evaluated as "smoothness,""moistness,""firmness," and "firmness." We decided to perform an absolute evaluation on a seven-point scale for each item of "wipeability."
The evaluation criteria are divided into 7 points: very good, 6 points: excellent, 5 points: somewhat good, 4 points: neither good nor bad, 3 points: somewhat bad, 2 points: bad, and 1 point: very bad. Ta.
The "overall evaluation" is the average score obtained by dividing the total score of the four items by 4.
The results for each item were plotted as shown in Figures 1 to 5, and the trends were clearly shown using line graphs. In addition, "actual" on the horizontal axis of the figure means an example, and "ratio" means a comparative example.
When these results are compared with the test conditions, the effects of the present invention become clear.

The sanitary thin paper obtained by the present invention can be used as is for general toilet paper, tissue paper, etc., such as wiping the toilet, hand wiping, baby wiping, nose blowing, object wiping, and body wiping. Examples include wiping applications.

Claims (5)

It is made of 3 or 4 layers of tissue paper,
The basis weight per sheet of the thin paper is 13.5 to 19.5 g/m ² ,
A coating liquid containing a water-based chemical liquid in an oil-based chemical liquid is applied to the outer layer sheet of the laminated base paper at a concentration of 3.0 to 20.0% by mass,
The oil-based coating liquid is
An aqueous chemical solution containing an oily component containing 50% by mass or more of liquid paraffin in an oily component content, 35% by mass to 65% by mass in an effective oily component amount excluding water, and containing glycerin as the main component. , containing 18% by mass to 55% by mass of effective aqueous components not containing water,
The water disintegrability of the product according to JIS P 4501 is 100 seconds or less, the dry strength (longitudinal direction) of the product is 300 to 850 cN/25 mm, and the dry strength (horizontal direction) is 110 to 400 cN/25 mm,
The moisture content of the product under JIS P 8111 environment is 4.5 to 11.5% by mass.
Sanitary tissue paper characterized by: The sanitary tissue paper according to claim 1, which does not contain a temporary wet paper strength enhancer. For a pulp paper stock with a mass ratio of NBKP:LBKP of 30:70 to 85:15 and which does not contain a temporary wet paper strength agent , a base paper is obtained through beating to a Canadian freeness of 300 to 600 CSF. and a step of using the base paper as the base paper for both outer layer sheets .
Producing the sanitary tissue paper according to claim 1 or 2 ,
A method for producing sanitary thin paper characterized by the following. The base paper of both outer layer sheets does not contain a temporary wet paper strength enhancer and also does not contain a dry paper strength enhancer, and the base paper of the intermediate sheet between both outer layer sheets does not contain a temporary wet paper strength enhancer. The method for producing sanitary tissue paper according to claim 3, further comprising a dry paper strength enhancer. The method for producing sanitary tissue paper according to claim 4, wherein the dry paper strength enhancer is applied to the base paper of the intermediate sheet at a rate of 10 to 17 kg/t based on the dry fiber weight .

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