JPH0274694A - Paper having wet paper tenacity and water dispersibility and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title paper suitable as baby wiper, wet tissue, sanitary napkin. etc., by subjecting a paper material containing compound fibers and a specific PVA-based fiber binder to wet paper making and impregnating the prepared paper with a solution containing a retaining agent of wet paper tenacity. CONSTITUTION:A paper material containing >=10wt.% compound fibers and 1.0-20wt.% PVA-based fiber binder having 500-90 deg.C dissolution temperature and 10-40 deg.C latent dissolution temperature is subjected to wet paper making to give paper, which is impregnated with a solution containing a retaining agent of wet paper tenacity (preferably ethylene glycol or propylene glycol) to give the aimed paper containing 1.0-20wt.% PVA-based binder having 90-97.5mol% saponification degree and >=10wt.% compound fibers wherein the PVA-based binder exists in a fibrous state and bonds the compound fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a paper that is easily dispersible in water and is wet, and a method for producing the same. More specifically, it is used as a disposable product such as various wipers used in wet conditions such as baby wipes, wet wipes for defecation, sanitary products, or medical gloves, and is disposed of in flush toilets etc. and easily immersed in water. The present invention relates to paper that is dispersed and does not cause blockages in sewer pipes, and a method for producing the same.

<Prior Art> Currently, paper and nonwoven fabrics used when wet with water have been devised to improve their water resistance in order to maintain paper strength when wet and muddy. For example, in the case of paper, a water-resistant emulsion binder is used, a wet paper strength agent is applied, and an emulsion process is applied.

In addition, in the case of non-woven fabrics, underwater entanglement method, needle punch method,
Furthermore, it is made of a compound*i nonwoven fabric using heat-melting binder fibers or a water-resistant emulsion binder. Since these are naturally water resistant, they cannot be dispersible in water and cannot be flushed into a flush toilet. For example, as described in JP-A-62-184193, the water dispersibility is block-like dispersion, which is sufficient for cine.

t7'l-% open/close 54-to4963 publication includes P
A method is provided in which a vA-impregnated sheet contains a gelling agent such as boric acid to form a wet sheet and is disposed of by pouring it into water.

This is not preferred as a skin cleansing material because it uses boric acid, which is highly toxic.

On the other hand, as a method for obtaining water-dispersible paper, for example, as disclosed in the examples of JP-A No. 59-144426, hot water-soluble polyvinyl alcohol is mixed with other paper materials, and wet paper making is carried out. There is a way to do it. In the paper obtained by this method, the mixed polyvinyl alcohol dissolves in the drying process after papermaking and acts as a binder by adhering and fixing other paper materials, but when disposed of in water, the polyvinyl alcohol dissolves. It will dissolve and the paper will become dispersed. However, if the polyvinyl alcohol used is soluble in hot water but difficult to dissolve in cold water, the water dispersibility of the paper will naturally be poor and the sewage pipes in flush toilets will be clogged. When using polyvinyl alcohol that dissolves in cold water to improve water dispersibility, there is a large dissolution loss of polyvinyl alcohol during paper making, and economic losses such as wastewater treatment and raw material costs during paper making are large. , which is practically impossible.

As shown in Japanese Patent Publication No. 55-38759, when a hydrothermally dissolvable polyvinyl alcohol binder is used, the mixing amount is reduced to 0.3 to 1.5% to improve water dispersion of paper. However, in this case, the binder effect is not sufficiently exerted, so the paper strength of the resulting paper decreases, and the generation of paper dust during use is significant.
The drawback is that it cannot withstand use. Furthermore, when these conventional papers are wetted with water to become wet paper, the strength of the paper is further reduced.

<Problems to be Solved by the Invention> The present invention solves the drawbacks of the prior art. A paper that is strong and dispersible in water, even in a dry state.
The present invention provides a water-dispersible paper that has excellent water running dispersibility, sufficient paper strength to withstand use, and a flexible and soft feel, and a method for producing the water-dispersible paper that is excellent in terms of economy and process control.

<Means for Solving the Problems> The present invention has a degree of saponification of 90 to 97.5 mol - polyvinyl alcohol binder effect of 0 to 20% by weight, contains compound fibers of 10% by weight or more, and A paper with low wet paper strength and water dispersion, characterized by comprising a paper in which an alcoholic binder exists in the form of fibers to bind the compound fibers, and a wet paper strength retaining agent impregnated in this paper. It is made of paper that has properties, and one layer of compound fiber is added
0 weight or more, a polyvinyl alcohol (hereinafter abbreviated as PVA)-based fibrous binder having a melting temperature of 50 to 90°C and a potential melting temperature of 10 to 40°C.
! A method for producing paper with high wet paper strength and dispersibility in water, which comprises wet-forming a paper stock containing a certain amount of water, and then impregnating the obtained paper with a liquid containing a wet paper strength retaining agent. be.

Wet paper strength retaining agent means a compound that can prevent the paper strength of wet paper from being significantly reduced by impregnating the paper with a liquid containing it. It is represented by the alcohol-based compounds shown below. That is, the alcoholic compound is preferably a water-soluble compound such as monovalent, divalent, trivalent or higher polyhydric alcohol, and polyoxyalkylene glycol represented by polyethylene glycol or polypropylene glycol.

Water-dispersible dust containing these wet paper strength retention agents,
A water-dispersed paper that has paper strength that can withstand use, is flexible, and has a soft feel, and a method for manufacturing the same will be described.

Here, the potential melting temperature of the PVA-based H1 fibrous binder is the melting temperature of the PVA-based fibrous binder in a state in which only drying is performed and no heat treatment is performed when manufacturing the PVA-based fibrous binder. This corresponds to the melting temperature of the PVA binder in the water-dispersed paper obtained using the binder.

The PVA-based fibrous binder used in the present invention is wet-spun by a conventional method using a water-soluble PVA solution having a saponification degree of 90 to 97.5 molt and a salt bath such as sulfur as a coagulation bath. Dry at 140°C, and then dry at usually 160°C to 250°C so that the melting temperature is 50°C to 90°C.
It is obtained by heat-treating it with water and then cutting it into appropriate fiber lengths. Although it retains its fibrous form only by drying after spinning, its melting temperature is 10 to 40°C and it is highly water-soluble. In the papermaking process, the PVA-based fibrous binder after the above-mentioned heat treatment is once wet-processed and usually has a
．． It is heated and dried at 30°C. In this drying process, the binder is dissolved by the moisture retained during papermaking and the heating during drying, and exhibits a binder effect. Therefore, the PVA-based fibrous binder exhibits a low melting temperature (i.e., potential melting temperature) corresponding to the melting temperature after drying after spinning. This is due to loss of water resistance.As mentioned above, wet papermaking is performed by using PVA with a saponification degree of 90 to 97.5 moles, which is originally extremely water-soluble, and temporarily imparting water resistance through heat treatment after fiber formation. We use a PVA-based fibrous binder that suppresses dissolution loss during papermaking, is economically superior, and facilitates process control, and is re-presented in the paper as a highly water-soluble PVA-based binder during the drying process after papermaking. This ingenious technique is the basis of the present invention, and therefore, the underwater dispersion paper of the present invention and its manufacturing method are completely new techniques not seen in the prior art.

A second feature of the present invention is that the wet paper strength agent is preferably
Water-dispersed paper that can be used in a wet state by immersing the water-soluble paper mentioned above in a solution containing 0% or more (values based on weight, hereinafter referred to as weight-based) and that can be flushed into a flush toilet. This is because it was made into a sex paper. As a wet paper strength retaining agent, P
Trihydric alcohols, which are second only to water as solvents or plasticizers for vA, such as glycerin, petriol% t-
+Aqueous solutions of dihydric alcohols such as butanediol, or polyoxyalkylene glycols'? A solution of holly 7' robylene glycol or a mixed solution thereof with water is used as a suitable representative example, and even if the above-mentioned water-dispersed paper is impregnated with this solution, surprisingly, the wet paper strength retaining solution It was found that the paper had sufficient strength to withstand use. The reason why these wet paper strength retaining agents inhibit the water solubility of PVA is unknown, but strangely, they have the property of easily dissolving in water when a large amount of water is present. That is, the present invention was first achieved by discovering the synergistic effect of the above-mentioned novel PVA binder and the use of a mixed aqueous solution of an alcoholic compound or the like that can act as a solvent for PVA.

The degree of saponification of the PVA-based fibrous binder of the present invention is from 90 to
If it is less than 90 moles, the water solubility is excellent, but the fibers will stick together in the drying process after spinning as described above, making it impossible to manufacture. Even after papermaking and drying, sufficient water solubility cannot be obtained, and the resulting paper has poor dispersibility in water.

(9) The PVA binder contained in the water-dispersed paper of the present invention is 1 to 20% by weight. If it is less than 1% by weight (unless otherwise specified, all percentages are by weight), sufficient paper strength cannot be obtained, and other paper materials cannot be bonded together sufficiently, resulting in a large amount of paper dust during use. do. If it exceeds 20 Xi%, the dispersibility in water will be poor and the paper obtained will not be loose and the texture will be impaired. Preferably it is 3 to 7%.

In general, when the content of PVA binder in paper is increased, the paper strength improves and the feeling of looseness increases. However, when using the present invention (using a PVA-based fibrous binder and interspersing the binder in the paper in the form of fibers), the binder spreads over the entire surface of other paper materials. Since the binder is not coated, even if the amount of binder is increased, the feeling of looseness is less likely to appear, and a paper with a flexible and soft feel can be obtained.

The fineness and fiber length of the PVA-based fibrous binder of the present invention are not particularly limited, but each is preferably 1
．． 0 to 2.0 denier, 2 to 10 cod.

The compound fibers constituting the underwater dispersion paper of the present invention are not particularly limited, and various types of compound fibers such as PVA-based, polyester-based, cellulose-based, polyolefin-based, polyamide-based, and acrylic thread rings can be used.

Also, the fineness and fiber length are not particularly limited,
It may be used as appropriate depending on the purpose, but from the viewpoint of the feel of the obtained underwater dispersion paper, preferably 0.2 to 3 deniers and 2 to 3 deniers.
1O1al.

The content of compound fibers also affects the feel, and in order to obtain a soft and soft feel, it is necessary to contain at least 10% of the compound 4Rm. Various natural pulps are mainly preferred as the paper stock to be used other than Compound 42m from the viewpoint of economy and paper-making properties, but Compound PJ
If the fiber content is less than 10%, the flexibility of the paper will be impaired, giving it a so-called paper-like and loose feel.

Alcohol-based compounds as wet paper strength retention agents include:
First, monohydric alcohols, specifically water-soluble linear or branched alcohols such as methanol, ethanol, globanol, butanol, propyl alcohol, and inflobil alcohol, and dihydric alcohols, specifically Specifically, ethylene glycol, furopanediol, 3-
Water-soluble alcohols such as methylbutane-1,3-diol, hexylene glycol, propylene glycol, and 1,3-butanediol, and trihydric alcohols, specifically glycerin, petriol (i.e.,
-methylpentane-1,3,5-) diol), and diethylene glycol;
Examples include water-soluble polyoxyalkylene glycols such as polyethylene glycol and polypropylene glycol.

The greater the proportion of these wet paper strength retaining agents mixed in with water, the higher the paper strength retaining effect, but if they are not mixed in, water will form and the paper will be dispersed in water. As a result of careful consideration of the mixing ratio, we found that it is desirable that the wet paper strength retention agent be mixed in the liquid at least 10%; less than 10% is preferable from the viewpoint of wet paper strength retention because the influence of water is large. do not have. More preferably, it is a case where the content is 40% or more.

In order to use the wet paper of the present invention for human body cleaning.

Although it varies depending on the part used, wet paper strength retention agents that meet the cosmetic raw material standards or the Japanese Pharmacopoeia standards and have no safety problems, specifically glycerin, 3-methylbutane-1,
3-diol, propylene glycol, 1,3-butanediol, polyethylene glycol, etc. are used. In addition, squalane, geraniol, and the like can also be used as wet paper strength retaining agents or as other additives.

It is also possible to impregnate medicinal agents, for example, crotamiton (crotonyl-N-ethyl-〇-toluidine) l.
OOWllb A commercially available system suitable for skin diseases such as eczema (trade name: Euratus) containing 2.5 ■ hydrocortisone and 5 caps of tocopherol acetate (vitamin E acetate) dissolved in water, chlorhexidine gluconate solution ( A commercially available drug (product name: Oronine Hv
It is also possible to use a solution prepared by dissolving K. ointment) in water.

In addition to these, various external medicines can be applied. For example, bactericides,
Analgesics, antipruritics, skin irritants, etc. are used.

For example, specific disinfectants include alcohols such as methanol, ethanol, and impropatol, oxyquinoline derivatives such as oxyquinolinic acid sulfate, boric acid and its derivatives such as boric acid, sodium borate, acrinol, and peroxide. Hydrogen water, hydrogen peroxide or its derivatives such as mercuric oxycyanide, phenol, phenol or its derivatives such as cresol, resorcinol, benzoic acid or its derivatives such as benzoic acid, sodium benzoate, benzyl benzoate, benzalkonium chloride , cationic surfactants such as benzethonium chloride, mercury-containing organic compounds such as mercurous chloride, mercuric chloride, yellow mercury oxide, phenylmercuric acetate, thimerosal, other silver nitrate, iodine or iodine compounds, thianthole (dimethylthianthrene) and ditoluene disulfide) methylrosaniline chloride, chloramine T.

There are various types such as hexachlorophene and nitrofurazone. Sulfa drugs such as xyloylsulfamine, sulfazine, sulfamine, sulfathiazole, sulfazine, sulfinxazole, sulfinmidine, phthalylsulfadeazole, erythromycin, chromphenicol, kanamycin, kanamycin sulfate, streptomycin sulfate, dihydrodeoxystreptomycin sulfate, Antibiotic dispersions such as hydroxystreptomycin sulfate can also be used.

Among these compounds, an appropriate and preferable drug may be selected depending on the intended use. Various drugs are also used as analgesic and antipruritic agents and skin stimulants, such as:
Examples of analgesic and antipruritic agents include clove oil, benzyl alcohol, and opium alkaloids; examples of skin irritation agents include camphor, salicylic acid and salicylic acid esters, t-menth-huyo:, t-menthol ester,
Examples include ammonia and isothiocyanate esters. It is also possible to add fresh fragrances.

Among the many compounds listed above, compounds belonging to alcohols also function as wet paper strength retaining agents.

Further, even if the compound is other than alcohols, if it is a compound that can significantly reduce paper strength when wet, it is also included in the wet paper strength retaining agent as referred to in the present invention.

Next, the present invention will be explained in more detail with reference to Examples.

However, the present invention is not limited to the embodiments described below.

Example 1 PIA with saponification degree of 96.0 molar and average polymerization degree of 1700
The powder was made into a 16% aqueous solution, which was spun in a saturated glass bath at 40°C from a spinneret with a pore size of 0.08 mm and 6000 holes, and the resulting nine threads were spun in a saturated glass bath at 90°C. 2.
Dry at 120℃ after 90 minutes with a 0x draft, and then dry at 180℃.
Shino with a single fiber fineness of 1.0 denier is obtained by heat treatment at ℃. This was cut into ffi fiber lengths of 3 to obtain a PVA-based fibrous binder.

The melting temperature 1t of the obtained PVA-based fibrous binder is 60°C.
The melting temperature after drying is 15°C.

Nine PVA-based fibrous binders obtained in this way, 3%;
Polyester fRm with a fineness of 2.0 denier and a fiber length of 5 mm.
(Kuraray EP203 After that, it was dried in a Yankee type dryer at 110°C to obtain a water-dispersed paper with a basis weight of 30.5 f/m.

Next, using polypropylene glycol with a degree of polymerization of 400 as a wet paper strength retaining agent, water was added to bring the concentration of the mixed aqueous solution to 1.
The sample paper was immersed at 20° C. for 24 hours at a bath ratio of 11,000. After soaking, the paper was removed from the bath by hand, and the strength of the paper was measured when water droplets stopped falling, and it was determined whether or not it could be used when wet. Furthermore, to determine the dispersibility of this paper in water, a cylindrical rotor with a diameter of 7 cods and a length of 3 Qm was placed in a 200 cc Ellemeyer flask containing 100 cc of water and placed on a magnetic stirrer. is 500RP
Adjust so that it becomes M±2ORPM. - A water-dispersible paper cut into a square with a side of 7 tx was put into an Elemeyer flask, and the time required to completely remove the original shape of one paper was measured and expressed as follows. This result is shown in the first difference.

◎: Within 10 seconds ○: Within 30 seconds Δ: Within 1 minute ×: 1 minute or more The physical properties or methods for measuring physical properties referred to in the present invention are as follows.

l) Dissolution loss rate The dissolution loss rate was determined by the following formula from the blending ratio (A) of the binder used in papermaking and the binder blending ratio (B) determined from the boiling loss of the obtained water-dispersible paper.

82) Melting temperature of PVA-based R fibrous binder The fibrous binder 2F of the cutting layer was dispersed in water 1007 at 5°C, and the water temperature was raised at 1°C per minute until the fibrous material was completely dissolved. It is expressed as the temperature at that time.

3) Paper tear length was determined according to JIS P-8113, and was expressed as an average value for length and width.

4) Determining whether or not it can be used when wet Dip a water-soluble sheet into the wet sheet for wet treatment, mark the wet paper with a weak X mark if it is weak and cannot be handled by hand, take it out, and fold the paper. A mark of ◎ was given to those that were heavily indulging in without causing fuzz or paper cuts when wiping hands, etc. In the middle,
Items that can be handled normally during cleaning are marked with an ○.

Comparative Example 1 PVA with saponification degree of 98.5 molt and average polymerization degree of 1700
A fibrous binder was obtained using the powder in exactly the same manner as in Example 1.

The melting temperature of the obtained fibrous binder was 60°C, and the actual melting temperature was 45°C. The fibrous binder was used in exactly the same manner as in Example 1 to obtain a basis weight of 31.
A paper of Ot/m' was obtained. The subsequent treatments and evaluations were carried out in the same manner as in Example 1 [7]. This is shown in Table 1.

As described above, Example 1 of the present invention can be used as a strong wet wiper for wiping and has water dispersibility.

On the other hand, in the case of Comparative Example 1, the wet paper strength is satisfactory, but
Because it has excellent water resistance, water dispersibility is not obtained.

Example 2 In place of the polyester fiber shown in Example 1, the fragility was 1.5.
A water-dispersed paper with a basis weight of 31.2 f/rn' was obtained in the same manner as in Example] using rayon fibers (rayon 3D1.5X5 manufactured by Daiwabo Co., Ltd.) having a denier and a fiber length of 5 m.

In addition, a mixed solution of water and glycerin is used as a wet paper strength retaining agent, and the glycerin concentration is 0%, 20%, 40%, and 60%.
, 100%, and otherwise treated in exactly the same manner as in Example 1, and wet paper strength and water dispersibility were evaluated.

The results are shown in Table 2.

As is clear from the above results, it is possible to obtain a sheet that can be used when wet with the wet paper strength retaining agent (glycerin).
Note that it is water-dispersible.

Claims (1)

[Scope of Claims] 1. Contains 1.0 to 20% by weight of a polyvinyl alcohol binder with a degree of saponification of 90 to 97.5 mol%, and 10% by weight or more of compound fibers, and the polyvinyl alcohol binder A paper having wet paper strength and dispersibility in water, characterized by comprising paper existing in the form of fibers and binding the compound fibers, and a wet paper strength retaining agent impregnated into the paper. 2. The paper according to claim 1, wherein the wet paper strength retaining agent is an alcohol compound. 3. The wet paper strength retaining agent is at least one selected from the group consisting of ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol.
The paper according to claim 1, which is a compound of seeds. 4. Compound fiber at 10% by weight or more, melting temperature 50-90
1.0 to 20% by weight of a polyvinyl alcohol-based fibrous binder having a potential melting temperature of 10 to 40°C.
1. A method for producing paper having wet paper strength and dispersibility in water, which comprises wet paper forming a paper stock containing the same, and then impregnating the obtained paper with a liquid containing a wet paper strength retaining agent. 5. The manufacturing method according to claim 4, wherein the wet paper strength retaining agent is an alcohol compound. 6. The wet paper strength retaining agent is at least one selected from the group consisting of ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol.
The manufacturing method according to claim 4, which is a seed compound.