KR101787652B1 - Sheet for laundry - Google Patents

Abstract

The present invention provides a laundry sheet which is completely dissolved in water and does not need to be removed after washing, has excellent washing performance, is easy to use, secures storage stability, and is not inconvenient at the time of use. The laundry sheet of the present invention is prepared using a polyvinyl alcohol polymer / copolymer, a main surfactant of a specific structure, and optionally a co-surfactant (preferably a nonionic surfactant, more preferably LA7 / LA9).

Description

{Sheet for laundry}

The present invention relates to a detergent for use in a washing machine. And more particularly to a sheet or film type detergent which is a formulation different from a common powder detergent or liquid detergent.

So far, powder detergent or liquid detergent has been used as a detergent to be used in a washing machine. Liquid detergents are relatively heavy and consumers are reluctant to use them. In the case of powder detergents, there is a phenomenon in which powder is blown, which necessitates a new type of detergent.

In order to solve such problems, US Pat. No. 4,605,509 discloses a technique of packaging a liquid detergent component and a fabric softener in a water-soluble film bag. However, in the case of fraction packing using water-soluble polymeric films, the sealing of the product during storage or transportation caused leakage of the contents. In addition, the storage stability of the product such as the exudation of the active ingredients on the surface of the film was very poor. In addition, the water-soluble film used as the packaging material is designed to have stability against moisture in the air and durability against the contents, but it takes a considerable time from low temperature to dissolution, Lt; / RTI >

Further, although a washing sheet using a liquid detergent by adsorbing a liquid detergent on a water-insoluble adsorbent sheet has been developed, there has been a drawback in that a water-insoluble adsorbent sheet must be removed after washing.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a washing sheet for use in a washing machine that is completely dissolved in a washing process, has excellent washing performance, is easy to manufacture, and has good storage stability.

In order to solve the above problems, the present invention provides a laundry sheet produced by using a sheet-forming polymer, a washing surfactant, etc., wherein the sheet-forming polymer is a polyvinyl alcohol or polyvinyl alcohol- Characterized in that the surfactant for the cleaning effect comprises a non-aromatic surfactant having no ethylene oxide group in the structure of the surfactant.

The laundry film according to the present invention is excellent in (1) easy dissolving even in low-temperature water, exhibiting excellent washing performance, (2) preventing the active ingredients of the liquid from leaking out of the sheet until entering the washing machine, (3) (4) moisture-absorbing ability by moisture in the air, and (5) excellent flowability, and (5) excellent washing performance.

The present invention relates to a pharmaceutical composition for the prevention and treatment of cancer such as gelatin, pectin, dextran, hyaluronic acid, collagen, agar, gum arabic, acacia rubber, alginic acid, sodium alginate, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose sodium, It is very preferable to use polyvinyl alcohol or polyvinyl alcohol copolymer among various polymers such as starch, polyvinylpyrrolidone, polyvinylmethacrylate, polyacrylic acid, and polyethylene oxide as a main substrate for forming a laundry sheet Based on discovery.

That is, unlike other film-forming bases, the polyvinyl alcohol or polyvinyl alcohol-based copolymer can retain the physical properties such as the tensile strength of the film even when a large amount of an active ingredient such as a high content of a surfactant is contained in the matrix formed thereby And it is possible to contain a large amount of surfactant per unit area relatively within the physical properties required for the sheet type detergent and to exhibit excellent washing performance even in the size of a tissue product such as a general wet tissue, .

Among the polyvinyl alcohol or polyvinyl alcohol-based copolymers having various molecular weights and degree of saponification, in the laundry sheet of the present invention, the film formation, the solubility, the ease of manufacture, the storage stability, the cleaning performance, the process Viscosity, etc.), it is preferable to use a polymer having a number average molecular weight of 10,000 to 100,000, more preferably 20,000 to 50,000, even more preferably 20,000 to 30,000.

Also, the degree of saponification of the polyvinyl alcohol or polyvinyl alcohol-based copolymer varies depending on whether the polymer is copolymerized or not, whether an alkali builder is used or the like, and the preferred degree of saponification is different for the purpose of the present invention. More specifically, when the polymer is polyvinyl alcohol and an alkali builder is not used, the degree of saponification is preferably 80-90%, and the polymer comprises a comonomer of the following formula 1 or 2, which is a preferred specific copolymer according to the present invention When an alkali builder is used, the degree of saponification is preferably 60-90%, more preferably 70-85%, even more preferably 70-82%.

The present invention also relates to a laundry sheet comprising a polymer, a surfactant and an alkali builder, wherein the polymer is a polyvinyl alcohol copolymer containing an anionic monomer unit having a carboxyl group, and the surfactant is a surfactant described below (Preferably an alkali metal salt of lauryl sulfate) having 8 to 18 carbon atoms.

As such a copolymer, a copolymer comprising a vinyl alcohol monomer unit and an anionic monomer unit represented by the following general formula (1) or (2), and an anionic monomer unit in an amount of 0.5-5 mol% is particularly preferable.

≪ Formula 1 >

(2)

In the general formulas (1) and (2), R1, R2, and R3 are independently H or methyl, and n is an integer of 0-3 independently from each other.

When PVA is used as a main formulating agent, there is a problem of being cured by an alkali builder. When a polyvinyl alcohol-based copolymer is used as a film-forming substrate instead of PVA, even when an alkaline builder, And the washing efficiency of the laundry sheet can be improved without degrading the solubility. However, not all anionic monomers are preferred as such monomers for a copolymer, and only an anionic monomer-containing copolymer having a carboxyl group is preferred for the purpose of the present invention. For example, a PVA copolymer having an anionic monomer having -SO ₃ H was gelled by an alkali builder, so that it was difficult for the sheet to dissolve after sheet production.

In addition, very particularly, in a laundry sheet comprising an alkyl sulfate metal salt, an alkali builder and a PVA copolymer, the degree of saponification of the PVA copolymer is preferably 60-90%, unlike the PVA, and more preferably 70-85% , With 70-82% being even more preferred. Specifically, when the saponification degree is too high, for example, when the saponification degree is too high, for example, when the saponification degree is too high, for example, when the saponification degree is too low, for example, when the saponification degree is less than 60% .

When the polyvinyl alcohol or polyvinyl alcohol copolymer is used as the main substrate of the laundry sheet, the present invention is very useful in the structure of the surfactant, particularly the nonionic surfactant, the anionic surfactant, and the amphoteric surfactant, It is difficult to predict that the non-aromatic surfactant having no ethylene oxide group as the main surfactant is very desirable for the purposes of the present invention such as film forming, cleaning performance, and stability. Particularly, in the non-aromatic surfactant having no ethylene oxide group in the structure of such a surfactant, an alkali metal salt of alkyl sulfate having 8 to 18 carbon atoms is more preferable, an alkali metal salt of lauryl sulfate is even more preferable, sodium lauryl sulfate is most preferable Do.

Preferably, it contains at least 50 wt%, more preferably at least 60 wt%, even more preferably at least 70 wt% of the main surfactant, based on the total surfactant weight.

When the surfactant is used as the main surfactant, a large amount of ethylene oxide groups are mixed in the surfactant structure such as sodium lauryl ether sulfate (SLES) or nonionic surfactant added with EO. This is thought to be the reason that the solubility of polyvinyl alcohol in water is lowered due to the property of drawing water molecules of the ethylene oxide structure itself and the physical properties of the laundry sheet are lowered. However, the present invention is limited to the theoretical assumption no.

In the case of a surfactant having an aromatic group such as a linear alkylbenzen sulphonate (LAS), the film-forming ability and the storage stability are very poor when it is made into a sheet together with polyvinyl alcohol. When a surfactant containing an aromatic group is used as a main surfactant, compatibility with polyvinyl alcohol or polyvinyl alcohol-based copolymer used as a film-forming substrate is poor and good film properties are not exhibited.

Thus, more preferably, the present invention relates to a laundry sheet comprising a polyvinyl alcohol polymer / copolymer and a surfactant, wherein said surfactant preferably comprises a surfactant which is free of ethylene oxide groups in its structure and which is non-aromatic , A surfactant which is free of such ethylene oxide groups and is a non-aromatic surfactant is meant to be contained in an amount of 50 wt% (more preferably 60 wt%, still more preferably 70 wt%) or more based on the total surfactant content More preferable.

Surfactants that do not have a non-aromatic ethylene oxide group used as the main surfactant include alkylsulfate salts of RSO ₄ ^- M ^{+ wherein} M is an alkali metal, preferably sodium or potassium, most preferably sodium, (Preferably a sodium salt), a fatty acid methyl ester sulfonate alkali metal salt (preferably a sodium salt), a fatty acid, an alkyl glycoside and the like can be used, and an alkylsulfate salt is particularly preferably used in the present invention , And, surprisingly, sodium lauryl sulfate is more preferable for various purposes such as forming the film of the present invention. The number of carbon atoms of the alkyl or alkane contained in the surfactant structure having no non-aromatic ethylene oxide group is preferably C8 to C18, and the fatty acid is preferably C8 to C18.

Although not limited in theory, in the case of alkylsulfate surfactants comprising C8-C22, preferably C8-C18, more preferably C12-C16 saturated hydrocarbons, the polyvinyl alcohol polymer / copolymer It is speculated that washing performance can be improved while forming a sheet formulation having a good strength even if a high content of surfactant is included. However, the present invention is not limited to this theoretical assumption.

Polyvinyl alcohol polymers / copolymers and surfactants (prepared using a non-aromatic surfactant that is greater than 50 wt%, more preferably greater than 60 wt%, of the surfactant and no ethylene oxide groups) The total content of the surfactant is 30 to 80% by weight (more preferably 40 to 70% by weight) based on the total weight of the sheet (after drying), and the content of the polyvinyl alcohol polymer / It is preferably 20 to 50% by weight (more preferably 30 to 50% by weight, still more preferably 35 to 50% by weight) based on the weight.

When the polyvinyl alcohol polymer / copolymer content is less than 35% by weight, the physical properties and strength of the sheet are good. However, there is a possibility that surfactant components may be deposited depending on storage conditions, The strength of the sheet is remarkably reduced in addition to the above-described problems, which may cause problems in use.

Such laundry sheets may contain other additives such as fluorescent dyes, enzymes, etc., which are described in detail below, in addition to the polyvinyl alcohol polymer / copolymer and the surfactant. When the content of the surfactant is lower than the above range, the washing performance is poor. When the content is higher than the above range, the content of the polyvinyl alcohol or polyvinyl alcohol copolymer is relatively reduced and it is difficult to prepare the sheet formulations.

Preferably, the present invention relates to a laundry sheet comprising a polyvinyl alcohol polymer / copolymer and a surfactant, wherein the surfactant

(a) a surfactant having no ethylene oxide group in its structure as a main surfactant and a nonaromatic surfactant (more preferably an alkylsulfate salt having a formula of RSO ₄ ^- M ⁺ , wherein M is an alkali metal, Is sodium or potassium, most preferably sodium), even more preferably sodium alkyl sulphate, most preferably sodium lauryl sulfate) and

(b) a laundry sheet comprising an auxiliary surfactant, heptaoxyethyl laiturated lauryl alcohol (LA7), nonaoxyethyl laiturated lauryl alcohol (LA9), or a mixture thereof.

The present invention also relates to a laundry sheet prepared by using a polyvinyl alcohol or polyvinyl alcohol copolymer and a surfactant as a laundry effective ingredient, wherein the surfactant is a surfactant having no ethylene oxide group in its structure and a nonaromatic surfactant LA7 or LA9 (preferably LA7), which is a nonionic surfactant, is used as an auxiliary surfactant, Is based on the surprising discovery that the cleaning performance can be improved very much while maintaining film formability. Surprisingly, when other surfactants with good cleaning performance were mixed in the polyvinyl alcohol polymer / copolymer and lauryl sulfate salt system, only LA7 or LA9 did not significantly reduce film formation or improved cleaning performance.

Therefore, the present invention also preferably provides the use of the LA7 / LA9 (preferably LA7) alone as the surfactant in the laundry sheet of the present invention, the lauryl sulfate salt (most preferably sodium salt) The present invention provides a laundry sheet produced using the same.

Preferably, the present invention provides a washing sheet characterized in that the mixing ratio (a: b) of (a) and (b) is 90:10 to 60:40, And the mixing ratio (a: b) of (a) and (b) is 80:20 to 70:30.

When the auxiliary surfactant LA7 or LA9 is mixed too much, the sheet may leak into the sheet to deteriorate the properties of the sheet and make it difficult to handle.

As a result, the present invention provides the above polyvinyl alcohol or polyvinyl alcohol copolymer; An alkylsulfate salt (M is an alkali metal, preferably sodium or potassium, most preferably sodium), which is alkyl having from 8 to 18 carbon atoms represented by the main surfactant RSO ₄ ^- M ⁺ (preferably sodium alkylsulfate, More preferably sodium lauryl sulfate); And an auxiliary surfactant LA7, LA9 or a mixture thereof, the content of the polyvinyl alcohol or polyvinyl alcohol copolymer is 30 to 50% by weight based on the total weight of the sheet after drying, Wherein the content of the lauryl sulfate salt as the main surfactant is 30 to 60% by weight, and the content of the auxiliary surfactant is 10 to 20% by weight.

The present invention is also based on the surprising discovery that, in formulations such as the present invention, it is desirable not to substantially use starch as a formulating agent (film forming substrate). As the starch was mixed with the formulating agent, that is, when the starch was included as a constituent of the sheet, the surfactant floated after drying (poor compatibility). As the starch content increased, the strength of the sheet also decreased. In addition, as the starch content increased, the solubility also decreased.

Substantially not used in the present invention means not containing 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, and still more preferably, not containing at all, relative to the dry weight of the sheet.

The laundry sheet according to the present invention may contain a fluorescent whitening agent to improve the washing performance or the film forming ability within a range that does not inhibit the formation of the film, storage stability, and ease of manufacture of the sheet. Enzymes (e. G., Cellulases, proteases, etc.); Alkali builders such as sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium metasilicate, sodium alkaline silicate, sodium neutral silicate, sodium tripolyphosphate, sodium pyrophosphate, sodium borate, zeolite (sodium aluminosilicate), sodium sesquicarbonate , MEA, TEA); Disintegration / disintegration adjuvants (for example, starch, cellulose derivatives, sodium chloride, citric acid, glycerin, propylene glycol); Fiber softening agents (for example, quaternary ammonium salt based cationic surfactants, silicone-based fiber softeners); Bleaches (for example, perborates, percarbonates, superphosphates, diacyl, tetraacyl peroxides); Dispersants / emulsifiers (e.g., polyoxyalkylene alkyl phenyl ethers, polyoxyalkylene alkyl ethers, polyoxyethylene polyoxypropylene block polymers); Sterilizing / disinfecting agents (for example, sodium hypochlorite, hydrogen peroxide, peroxide element); Spices; antiseptic; Pigment; Antimicrobial agents, and the like .

The thickness of the laundry sheet according to the present invention is preferably 1 to 1 cm, more preferably 5 to 0.5 cm, most preferably 50 to 1 mm. When the thickness of the dried laundry sheet is less than 1 탆, the supporting of the effective ingredient is insufficient, the strength of the film is weak and it is difficult to obtain the desired performance. If the thickness of the dried laundry sheet exceeds 1 cm, May be deteriorated.

More preferably, the present invention relates to a PVA composition comprising 20 to 50 wt% (preferably 30 to 50 wt%) of PVA, 30 to 50 wt% of SLS, 10 to 20 wt% of LA7 / 9, 1 to 5% by weight of a white bait, and optionally 1 to 5% by weight of an enzyme. The sheet-type laundry detergent of the present invention is completely dissolved in the laundry tub when it is put in the laundry tub and is not required to be removed.

The laundry sheet according to the present invention may also contain the above-mentioned polyvinyl alcohol or polyvinyl alcohol-based copolymer; The main surfactants described above; And the above-mentioned auxiliary surfactants, other auxiliary surfactants may be further contained within a small amount which does not impair the object of the present invention. Such a surfactant may further include a surfactant having an ethylene oxide group in the surfactant structure, and sodium laureth sulfate may be used as a surfactant having an ethylene oxide group in such a structure.

The laundry sheet according to the present invention may also contain the above-mentioned polyvinyl alcohol or polyvinyl alcohol-based copolymer; In addition to the main surfactant, the surfactant may further include an aromatic surfactant as a cosurfactant within the range not impairing the object of the present invention, and alkylbenzenesulfonate may be used as such an aromatic surfactant, Is preferably a linear alkyl having from 8 to 18 carbon atoms.

The laundry sheet of the present invention can be used in a state in which two or more layers of sheets other than the single-layer sheet according to the present invention are laminated and integrated.

The laundry sheet according to the present invention is prepared by dissolving a polyvinyl alcohol or polyvinyl alcohol copolymer in an appropriate amount of water to prepare a polyvinyl alcohol polymer / copolymer solution, mixing the other ingredients such as a surfactant well, And then drying it. Further, other components such as a surfactant can be dissolved before the polyvinyl alcohol or polyvinyl alcohol copolymer is dissolved in water, and the laundry sheet of the present invention is not limited to the above-mentioned production method.

The present invention is also based on the fact that it is preferable to further include a bubbling process during the above-mentioned manufacturing process in order to improve the water solubility of the sheet of the present invention. Through the bubbling process, If the specific gravity is adjusted to 0.6 to 0.9, various advantages such as water solubility and storage speed of the sheet can be highlighted. Accordingly, the present invention provides a method for producing a polyvinyl alcohol copolymer, comprising: preparing a solution containing a polyvinyl alcohol or polyvinyl alcohol-based copolymer and a surfactant; Bubbling; And a drying step of drying the laundry sheet.

Therefore, the present invention also has the above-mentioned technical characteristics, and also provides a laundry sheet to which a specific gravity of 0.6 to 0.9 is added.

The present invention provides a laundry sheet which is completely dissolved in water and does not need to be removed after washing, has excellent washing performance, is easy to use, secures storage stability, and is not inconvenient at the time of use.

Fig. 1 shows experimental results showing changes in sheet tensile strength according to PVA molecular weight, PVA content and water content relative to solids content. The first number in the X-axis value "03-40-170" in FIG. 1 means the degree of polymerization / 100 (ie, 03 means the degree of polymerization 300), the second number means the content of PVA , And the third number means the water content (wt%) with respect to the solids content. The PVA molecular weight is approximately 50 times the polymerization degree. The Y-axis value means the tensile strength and the unit is kgf / cm ² .
Figure 2 shows the results of the change in tensile strength caused by replacing a portion of the PVA used as the formulation agent with starch. The Y-axis value of the graph means the tensile strength and the unit is kgf / cm ² . In Fig. 2, the red line is a boundary line showing 5 kgf / cm ² , which is the minimum tensile strength required for sheet usability (easily tearable or crumbling when it is less).
Figure 3 is a graph showing the viscosity changes as the molecular weight of PVA increases under certain content conditions. At this time, the water content standard of each compound is 240% of the solid content.

Hereinafter, embodiments of the present invention will be described in detail to facilitate understanding of the present invention. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the following embodiments. Embodiments of the invention are provided to more fully describe the present invention to those skilled in the art.

<Example 1> Selection of a polymer suitable for a laundry sheet

The film formability, solubility and storage stability of the polymer were evaluated while preparing a laundry sheet using various polymers shown in Table 1 below. The results are shown in Table 1 below.

100 g of the polymer was dissolved or suspended in an appropriate amount of distilled water or ethanol (about 400 g) to prepare a polymer solution or suspension. The polymer solution or suspension was placed on a release film and then made into a certain thickness using a film applicator from Elcometer, followed by drying in a drying oven at 115 ° C for 10 minutes to prepare a laundry sheet (thickness: 0.01 cm). The sheet formation process and the sheet formed after the production were used to evaluate film formation in three stages of excellent, normal, and defective.

Solubility was evaluated as follows. The prepared film sheet was cut into 5 cm x 5 cm, and 300 ml of 15 ° C water was added to a 500 ml beaker, followed by stirring at a constant speed. The time taken for the film to completely disintegrate and dissolve was measured and evaluated in three stages: Excellent (within 3 min), Normal (3 min -5 min) and Defective (Over 10 min).

Film formation Solubility Other reviews Polyvinyl alcohol Great Great Good water solubility Polyacrylic acid usually Great At high pH, neutralized, it dissolves well in water, but the formed film brittle. Polyethylene glycol Bad usually - Polyacrylamide Bad Great - Polyvinylpyrrolidone Great Great Soluble in ethanol and organic solvents Poly ATC Great Great Very hygroscopic Poly DMAEMA Great usually Solubility is ensured at low pH Poly HEA Great usually - Cellulose (HEC) usually usually - Cellulose (HPMC) usually usually -

In Table 1, ATC means [2- (acryloyloxy) ethyl] trimethylammonium chloride, DMAEMA means dimethyl aminohexyl methacrylate, HEA means hydroxy ethyl acrylate, HEC means hydroxyethylcellulose, HPMC means hydroxypropylmethylcellulose it means.

As shown in Table 1, polyvinyl alcohol is most preferable as a polymer for producing a laundry sheet from the viewpoints of forming a film for producing a laundry sheet, solubility of the produced sheet, ease of manufacture, storage stability, and the like .

&Lt; Example 2 > Evaluation of influence of PVA content and molecular weight

In addition, polyvinyl alcohol having various molecular weights and degree of saponification was used to evaluate film formation, solubility, ease of manufacture, storage stability, washing performance, and process (viscosity of the liquid mixture) More preferably a polymer having a molecular weight of 20,000 to 50,000 is used and still more preferably a polymer having a molecular weight of 20,000 to 50,000 is used for the purpose of the present invention in consideration of the relationship with the content of the polyvinyl alcohol or polyvinyl alcohol copolymer, PVA or a copolymer thereof is preferably 30,000. When the alkali builder is not mixed in the degree of saponification, the polymer preferably has a degree of saponification of 80-90%. When the PVA copolymer is used and the alkali builder is mixed, the degree of saponification is 60-90% , Preferably 70-85%, and even more preferably 70-82%). When the degree of saponification is lower than the degree of saponification, the water solubility is lowered. In the case of using a polymer having a degree of saponification higher than that of saponification degree, a gelling phenomenon has been a problem.

Specific experimental results showing the above contents are shown in Tables 3 and 4 below. The preparation and evaluation of the sheet were carried out in the same manner as in Example 1. At this time, the casting condition was 1100 탆 (compound coating thickness) and the drying condition was 115 캜 for 15 minutes. ("Post-drying surface"), including burying scale, and the like. For example, a point on a film has no abnormality but it is on the surface, and a point on the surface means that a phase separation occurs on the surface of the film and a surface appears on the surface. The evaluation criteria of solubility and tensile strength are shown in Table 2 below.

Evaluation results Very good Great usually Bad Solubility ◎
(Within 3 minutes) ○
(Within 5 minutes) △
(Within 10 minutes) ×
(More than 10 minutes) The tensile strength
(kgf / cm ² ) ◎
15 or more ○
over 10 △
5 or more ×
5 or less

(PVA, SLS, LA7, etc.) Content was adjusted to 100% when surfactant (SLS, LA7) was changed or decreased when the content of polymer was changed. The content was fixed at 5% by weight. 40% by weight of PVA, 45% by weight of SLS, 10% by weight of LA7 and 5% by weight of other ingredients (Prescription No. 1) were used as the basic prescription. In the following table, the PVA content means the weight percentage of PVA in the total solids excluding water, and in the case of the water content, it means the weight percentage of water with respect to the total weight of solid content when the blend is prepared. That is, in the formula 1, the PVA content of 40% means that PVA is contained in 40% by weight of the total solids, and the water content of 63% means that the solids content is 37% Therefore, when the solid content is taken as 100, it means that the water content is about 170.

* For the 13th prescription, 2 minutes of drying time was added.

As shown in Tables 3 and 4, when the PVA number average molecular weight was about 15,000 or less, the sheet strength was poor and the surface surfactant floated after drying (poor compatibility). In order to solve this problem, the PVA content in the sheet was increased to secure the sheet formability and strength, but the content of the active ingredient was lowered, thereby lowering the washing performance.

On the other hand, as the molecular weight increased, the sheet surface was stabilized (improved compatibility) and the sheet strength was increased. Therefore, the higher the molecular weight, the better the sheet formability can be ensured at a low PVA content, but the viscosity of the blend liquid is too high, so that it is difficult to ensure a fairness suitable for mass production. On the other hand, in order to improve this, that is, the water content can be increased to lower the viscosity, but the productivity is greatly reduced.

 Consequently, it is preferable that the number average molecular weight of the PVA or the copolymer thereof used in terms of compatibility with the sheet strength and the laundry effectiveness component is 20,000 or more. In addition, since the PVA or its copolymer has a number average molecular weight of not more than 50,000, preferably not more than 5,000 cps in a certain PVA content (about 30%) and a water content (240% Or less.

In this connection, when a sheet is produced using 30 wt% of PVA, 52 wt% of SLS, 13 wt% of LA7 and 5 wt% of other components and 240 parts by weight of water based on 100 wt% of the solid content of the sheet, The viscosity of the polymer solution was measured. The results are shown in FIG. It is not preferable that the viscosity of the polymer solution used in the manufacturing process is too high or too low. In the case of the polymer solution having the same kind of components as the present invention, the viscosity of the polymer solution rapidly increases from the molecular weight of about 50,000.

The results of measurement of changes in sheet tensile strength according to molecular weight, PVA content, and water content relative to solids content are shown in FIG. In terms of sheet usability, it is required to be at least 5 kgf / cm ² (easily torn or broken when it is less than 5 kgf / cm ² ), and it is considered to be a good level when it is 10 kgf / cm ^{2 or} more. In terms of tensile strength, Prescription, 10-40-170 prescription, 15-30-200 prescription, 10-40-200 prescription, 15-40-240 prescription, 10-30-200 prescription, 10-35-200 prescription were desirable.

Example 3 Evaluation of Main Surfactant

Washing sheets were prepared according to the ingredients and contents shown in Table 5 below, and the film forming and washing performance of the sheets thus prepared were compared and evaluated.

number ingredient Content (unit%) One Polyvinyl alcohol (PVA) 40% 2 The surfactants of Table 3 55% 3 Fluorescent brightener 2 % 4 enzyme 1.5% 5 Incense and other 1.5%

Specifically, 145 g of PVA (degree of saponification: 86.5%, average degree of polymerization: 500) was added to 630 g of distilled water and dissolved at 80 DEG C for 2 hours to prepare a PVA solution. The remaining components of Table 2 were added to the prepared PVA solution and mixed using a mechanical stirrer. The mixed solution was placed on a release film, and then the PVA sheet was prepared using a film applicator manufactured by Elcometer, and then dried in a drying oven at 115 ° C. for 10 minutes to prepare a PVA sheet containing a surfactant as a cleaning component.

Table 6 shows the evaluation results of film forming and cleaning performance depending on the type of surfactant. The film formation was evaluated in three steps of excellent, normal, and defective in the same manner as in Example 1 above. The cleaning performance was evaluated by the following methods. When the cleaning power was 60% or more, 50-59%, and 50%, respectively, it was judged as poor.

Specifically, the washing power was evaluated by using a washing machine having the same condition. At this time, general tap water was used as the washing water channel. In addition, cold water, which is the same as that used in ordinary households, was used for washing. The contaminated cloth used for the evaluation of detergency was an artificial wet polluted cloth and protein contaminated cloth EMPA 116 manufactured by the Japan Cleanup Association. In addition, the contaminated cloth was attached to an actual cotton T-shirt and evaluated. In addition, 16 specimens of 5 ㎝ × 5 ㎝ in size were used for statistical analysis. At this time, the W _B value indicating the degree of whiteness of the contaminated cloth was measured using a colorimeter before and after washing. The laundry sheet prepared in the above example was cut into a size of 20 cm x 15 cm, and two pieces of the cleaned detergent were used. Washing sheets prepared in the examples were put into the washing machine together with contaminated cloths at the initial stage of washing. The washing conditions were performed on a heavy water in a standard course (washing 20 minutes, rinsing 2 times) of the washing machine, 25 [deg.] C, 20% RH) for 1 day, ironed and measured for WB value in the same color difference meter. The obtained results were substituted into the Cubelka munch equation represented by the following equation (2) to calculate the cleaning power. The results are shown in Table 6 below.

In the above formula (1), Rs represents the surface reflectance of the contaminated cloth, Rc represents the surface reflectance of the contaminated cloth after the washing process, and Ro represents the surface reflectance of the white cloth.

Kinds designation Film formation Cleaning performance Remarks Nonionic surfactant LA5 (pentaoxyethylated lauryl alcohol)
(Polyoxyethylene Lauryl Ether) Bad usually Liquid phase LA7 (heptaoxyethylated lauryl alcohol) Bad Great Liquid phase LA9 (nonaoxyethylated lauryl alcohol) Bad Great Liquid phase LC7 (Laureth-7-citrate) Bad usually Liquid phase CA7 (Polyoxyethylene cetyl ether) Bad usually Semi-solid CA9 Bad usually Semi-solid CA15 usually usually Semi-solid SA14 (Polyoxyethylene stearyl ether) usually usually Semi-solid OA14 (Polyoxyethylene oleyl ether) usually usually Semi-solid AG200 (Alkyl glucoside) usually usually 50% solution C-MEA (Coconut Acid Monoethanol Amide) usually Bad elegance Anionic surfactant SLES 2 (sodium laureth sulfate) Bad Great 70% solution SLES 3 Bad Great 70% solution SLS (sodium lauryl sulfate) Great Great elegance SAS (sodium alkanesulfonate) Bad usually 25% solution ALS (Ammonium Lauryl Sulfate) Bad usually 26% solution AOS (Alpha Olefin sulfonate) Bad Great 35% solution ALES 3 mol (Ammonium Laureth Sulfate) Bad Great 30% solution LAS (linear alkylbenze sulphonate) -MEA (mono ethanol amine) Bad usually Semi-solid LAS-Na (Soduim linear alkylbenze sulphonate) Bad usually Semi-solid Lauric acid-K (Potassium Laurate) Bad Bad elegance Myristic acid-K (Potassium Myristrate) Bad usually elegance MES (methyl ester sulfonate) Bad usually elegance Amphoteric surfactant Amine-oxide Bad Bad 30% solution Cocamidopropyl Betaine usually Bad elegance

Surprisingly, as shown in Table 6 above, when polyvinyl alcohol was used as the polymer substrate, only sodium laurylsulfate (SLS) was excellent in film formation, and various other detersive surfactants were found to have normal or poor film formation Respectively. For example, surfactants such as LAS, SLES, and MEA have a poor compatibility with PVA due to phase separation during the production process, and the prepared sheets are sticky or broken, and thus the prepared sheets have poor storage stability and ease of handling .

&Lt; Example 4 > Selection evaluation of cosurfactant

Various laundry sheets according to the prescription of Table 7 were prepared and evaluated using sodium lauryl sulfate as a main surfactant and various nonionic surfactants as an auxiliary surfactant. The laundry sheets were prepared in the same manner as in Example 3 above.

Item Example a b c d e f g h i j k Polymer
matrix PVA ⁽¹⁾ 40 40 40 40 40 40 40 40 40 40 40 Nonion
Surfactants LA5 15 - - - - - - - - - - LA7 - 15 - - - - - - - - - LA9 - - 15 - - - - - - - - LC7 - - - 15 - - - - - - - CA7 - - - - 15 - - - - - - CA9 - - - - - 15 - - - - - CA15 - - - - - - 15 - - - - SA14 - - - - - - - 15 - - - OA14 - - - - - - - - 15 - - AG200 - - - - - - - - - 15 - C-MEA - - - - - - - - - - 15 Anion
Surfactants SLS ⁽²⁾ 40 40 40 40 40 40 40 40 40 40 40 additive Fluorescent dyes ⁽³⁾ 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 enzyme 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Incense and other 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Sum Sum 100 100 100 100 100 100 100 100 100 100 100

In Table 7, PVA ⁽¹⁾ has a degree of saponification of means that the polyvinyl alcohol of 86.5%, average polymerization degree of 500 and, SLS ⁽²⁾ is sodium lauroyl sulfate, and the fluorescent dye ⁽³⁾ include Tinopal CBS-X (Ciba Specialty Chemical) was used.

The prepared laundry sheets were tested in the same manner as in Example 1 or 3, and evaluated according to the criteria in Table 8 below. The results are shown in Table 9 below.

The film tensile strength was evaluated as follows. The test method was according to ISO 527-3 standard test method, and Zwick 1120 universal testing machine was used. The test specimens were cut into 2 × 10 cm (cm ² ) by 0.2 mm each with a screw grip. The grip distance was maintained at 50 mm and the tensile test was carried out at a speed of 20 mm / min. Respectively. The tensile strength was determined as the point at which the film was cut without being able to overcome the force, and the values in Table 8 were taken as reference values in consideration of convenience in use.

Evaluation results Very good Great usually Bad Solubility ◎
(Within 3 minutes) ○
(Within 5 minutes) △
(Within 10 minutes) ×
(More than 10 minutes) The tensile strength
(kgf / cm ² ) ◎
15 or more ○
over 10 △
5 or more ×
5 or less

Example a b c d e f g h i j k Cleaning power (%)
(Japan Cleanup Association contamination) 60 71 70 64 58 66 64 67 62 68 58 Cleaning power (%)
(Protein contamination, EMPA 116) 66 68 67 68 64 66 65 68 60 62 56 Solubility ◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ○ ○ The tensile strength ○ ◎ ◎ ○ ◎ ◎ ◎ ◎ ○ ○ ◎

As shown in Table 9, LA7 and LA9 were superior to other nonionic surfactants in terms of cleaning power and physical properties, and LA7 was somewhat superior to LA9 in terms of cleaning power.

<Example 5> Evaluation of effect of SLS content, which is a main surfactant, and LA7 content, an auxiliary surfactant

As shown in Table 10 below, the contents of SLS as the main surfactant and LA7 as the cosurfactant were changed to prepare a laundry sheet. The manufacturing method was the same as in Example 4.

Ingredient / Content (% by weight) Example 5-1 Example
5-2 Example
5-3 Example
5-4 Example
5-5 Example
5-6 Polyvinyl alcohol (PVA) 40% 40% 40% 40% 40% 40% Sodium lauryl sulfate 55% 50% 45% 40% 35% 30% LA7 0% 5% 10% 15% 20% 25% Fluorescent dye (Tinopal CBS-X, Ciba chem.) 2% 2% 2% 2% 2% 2% The enzyme (Savinase-16L, Novozyme) 1.5% 1.5% 1.5% 1.5% 1.5% 1.5% Incense and other 1.5% 1.5% 1.5% 1.5% 1.5% 1.5% Sum 100% 100% 100% 100% 100% 100%

The film forming and cleaning performance of the thus-prepared laundry sheet was evaluated in the same manner as in the evaluation method of Example 4, and is shown in Table 11 below.

Sample Film formation Cleaning performance (%) Japanese Pollution EMPA116 Example 5-1 Great 65 55 Example 5-2 Great 67 58 Example 5-3 Great 69 62 Examples 5-4 Great 71 68 Example 5-5 usually 72 66 Examples 5-6 Bad 68 60

As shown in Table 11, the content of SLS was preferably 40 to 50% by weight based on the total weight of the sheet, and 5 to 15% by weight of the nonionic surfactant LA7 in consideration of film forming and cleaning performance.

<Example 6> Comprehensive evaluation

The water-soluble sheet was prepared according to the formulation and contents shown in Table 12 below, and various aspects were evaluated. The manufacturing method was the same as in Example 4.

Item Example Comparative Example a b c d e f g h i j k l a b c Polymer
matrix PVA 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 Nonion
Surfactants LA7 0 5 10 15 20 25 15 15 15 15 - - 55 - - Anion
Surfactants SLS 55 50 45 40 35 30 30 20 10 0 57 56.5 - - - SLES - - - - - - 10 20 30 40 - - - 55 - AOS - - - - - - - - - - - - - - 55 additive Fluorescent dye 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 0 2.0 2.0 2.0 2.0 enzyme 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 0 1.5 1.5 1.5 Incense and other 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Sum Sum 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

In Table 12, PVA having a degree of saponification of 86.5% and an average degree of polymerization of 500 was used. As the nonionic surfactant, LA7, which is a polyoxyethylene alkyl ether, was used. AOS means? -Olefin sulfonate, Tinopal CBS-X (Ciba Specialty Chemicals) was used.

Sheet Formation  evaluation

Formation of the water-soluble sheet detergent prepared in Comparative Examples and Examples was evaluated according to the following criteria through visual observation or the like, and the results are shown in Table 13 below.

◎: The sheet formulation is flexible and does not show any phenomenon.

○: The sheet formulation is flexible, but the liquid component is slightly stained.

?: Insufficient sheet flexibility and slight appearance

X: The sheet was not formulated and a large amount of liquid component was present.

Example Comparative Example a b c d e f g h i j k l a b c Sheet Formation ◎ ◎ ◎ ◎ ○ △ ○ ○ △ △ ◎ ◎ × △ ×

As shown in Table 13, the sheet formations of Examples a, b, c, d, k and l were excellent, and the film formation was remarkably deteriorated when the nonionic surfactant and SLES content were increased.

Solubility and The tensile strength  evaluation

The washing sheets prepared in the above Examples and Comparative Examples were tested in the same manner as in Example 4, and their solubility and tensile strength were evaluated. The results are shown in Table 14 below.

Example Comparative Example a b c d e f g h i j k l a b c Solubility ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ ◎ - ○ - The tensile strength ◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ △ ◎ ◎ - △ -

In the case of Comparative Examples a and c, no sheet form was formed and it was impossible to measure the solubility and tensile strength.

As shown in Table 14, the solubility and tensile strength of Examples a, b, c, d, k and l were both excellent.

Detergency evaluation

The cleaning performance of the laundry sheets prepared in Examples and Comparative Examples was evaluated by the following method (in Comparative Examples a and c, the same amount of the active ingredient mixture was evaluated in place of the water-soluble detergent sheet).

Specifically, the washing power was evaluated by using a washing machine having the same condition. At this time, general tap water was used as the washing water channel. In addition, cold water, which is the same as that used in ordinary households, was used for washing. The contaminated cloth used for the evaluation of detergency was an artificial wet polluted cloth and protein contaminated cloth EMPA 116 manufactured by the Japan Cleanup Association. In addition, the contaminated cloth was attached to an actual cotton T-shirt and evaluated. In addition, 16 specimens of 5 ㎝ × 5 ㎝ in size were used for statistical analysis. At this time, the WB value indicating the degree of whiteness of the contaminated cloth was measured using a colorimeter before and after washing. The laundry sheet prepared in the above example was cut into a size of 20 cm x 15 cm, and two pieces of the cleaned detergent were used. The washing conditions were performed on the standard washing course (washing 20 min, rinsing 2 times) over heavy water, and the dehydrated contaminated cloth was placed in a constant temperature and humidity chamber (25 ° C , 20% RH) for one day, ironed and measured for W _B values in the same colorimeter. The obtained results were substituted into the same Cuvelka Munch equation as in Example 3 to calculate the cleaning force. The results are shown in Table 15 below.

Example Comparative Example a b c d k l a b c Cleaning power (%)
(Japan Cleanup Association contamination) 65 67 69 71 55 58 72 64 60 Cleaning power (%)
(Protein contamination, EMPA 116) 55 58 62 68 52 50 48 66 62

As shown in the above Table 15, it was confirmed that, in Examples 1, b, c, d, k and 1 having proper sheet formability, solubility and tensile strength, 15% by weight of a polyoxyethylene alkyl ether as a nonionic surfactant The washing performance of Example d was the best.

Example 7 Evaluation of stability (hygroscopicity)

The stability of the laundry sheet prepared in Example 6 of Example 6 was evaluated, and the results are shown in Table 16 below.

After 1 month Two months later Remarks Dry residue Film condition Dry residue Film condition Room temperature 96% Good 96.5% Good The moisture in the sheet is dried and the sheet is liable to be broken, but the solubility is not greatly different. 50 degrees 97% Good 97.5% Good Frozen / thawed
(cycle: -15 to 50 ° C) 95.5% Good 96% Good Almost no change from the initial state. 30 degrees, 80% humidity 94.5% Good 94% Good It feels a little damp, but it does not stick to your hands, it is not sticky, and the film is a little soft. daylight 96% Good 96.5% Good Similar to room temperature

The initial sheet dry residue was 95 wt%, and the moisture content was 5 wt%. After drying for 10 minutes at 105 ° C using a Halogen moisture analyzer, the dry residue was measured.

As shown in Table 16, although it was a water-soluble sheet detergent, stability as a product could be secured under various conditions including high temperature and high humidity and rainy season conditions.

Example 8 Evaluation of Use of PVA Copolymer

A sheet for washing was prepared according to the prescription of Table 17 below.

Item Example a b c d e f g h i Polymer
matrix PVA ⁽¹⁾ 40 40 - - - - - - - PVA copolymer ⁽²⁾ - - 40 40 40 40 40 40 40 Nonion
Surfactants LA7 15 13.5 15 14.3 13.6 13.0 12.3 11.6 10.9 Anion
Surfactants SLS ⁽³⁾ 40 36.4 40 38.2 36.4 34.5 32.7 30.9 29.1 additive Builders ⁽⁴⁾ - 5 - 2.5 5 7.5 10 12.5 15 Fluorescent dyes ⁽⁵⁾ 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 enzyme 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Incense and other 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Sum Sum 100 100 100 100 100 100 100 100 100

In Table 17, PVA ⁽¹⁾ means polyvinyl alcohol having a degree of hydrolysis of 86.5% and an average degree of polymerization of 500, and PVA copolymer ⁽²⁾ means vinyl alcohol (98 mol%, degree of saponification: about 77 mol%) - methacrylic acid Sodium laureth sulfate was used as SLS ⁽³⁾ , sodium carbonate (soda) was used as the builder ⁽⁴⁾ , Tinopal CBS-X was used as the fluorescent dye ⁽⁵⁾ (Ciba Specialty Chemicals).

The manufactured laundry sheets were evaluated in the same manner as in Example 4, and the results are shown in Table 18 below.

Example a b c d e f g h i Cleaning power (%)
(Japan Cleanup Association contamination) 71 64 70 70 72 71 68 66 64 Cleaning power (%)
(Protein contamination, EMPA 116) 68 60 67 69 72 76 74 72 68 Solubility ◎ X ◎ ◎ ◎ ◎ ◎ ◎ ◎ The tensile strength ◎ △ ◎ ◎ ◎ ○ ○ △ △

As shown in Table 18, when a builder is added to PVA, the PVA is cured and the solubility and physical properties are remarkably deteriorated. However, when the PVA copolymer was used, the builder did not cause hardening even when the builder was added, and the detergency was improved by the builder. Also, when the amount of the builder was 7.5% or more, the sheet strength was reduced by a large amount of builders in the film.

&Lt; Example 9 > Evaluation of influence of addition of starch

Sheets having the formulations shown in Table 19 below were prepared, and the effect of adding starch was evaluated while using PVA, starch, or a mixture thereof as a formulating agent. The results are summarized in the following Table 20, and tensile strengths of the results of Table 20 are shown in FIG.

Raw material content One Formulation topic 40% 2 SLS 45% 3 LA7 10% 4 Other 5% water 170 (sheet solid content 100)

Formulation topic
PVA / Starch
(total 40%) Casting after drying
surface Solubility The tensile strength
(kgf / cm ² ) Remarks A 1/0 Good Good ◎ 10.7 (○) B 3/1 Good Floating phenomenon (3 points) X (Hazy) 6 (?) Starch powder sinks 3/1 (luxury starch) Good Floating phenomenon (3 points) ◎ 5.3 (△) C 2/1 Good Floating phenomenon (4 points) X (Hazy) 4.1 (X) Starch powder sinks 2/1 (luxury starch) Good Floating phenomenon (4 points) ◎ 4.1 (X) D 1/1 Good Floating phenomenon (4 points) X (Hazy) 2 (X) Starch powder sinks 1/1 (luxury starch) Good Floating phenomenon (4 points) Δ 2.1 (X) A little stagnation left

As shown in Table 20 and FIG. 2, when the starch was mixed with the formulating agent, that is, when the starch was included as a sheet component, the surfactant floated after drying (poor compatibility), and the starch content was increased The strength of the sheet was also decreased. In addition, as the starch content increased, the solubility also decreased. Therefore, it was understood that it is preferable not to use starch while manufacturing the laundry sheet according to the present invention. In order to overcome the compatibility and tensile strength problems, there is a problem that the content (50% or more) of the formulating agent in the sheet has to be increased, and starch has to be first smoothened to improve the solubility.

Claims (28)

A laundry sheet produced by using a polyvinyl alcohol or polyvinyl alcohol copolymer as a polymer and containing a surfactant,
Wherein the surfactant comprises an alkali metal salt of alkyl sulfate having 8 to 18 carbon atoms,
Wherein the alkali metal salt of alkyl sulfates having 8 to 18 carbon atoms is a main surfactant containing not less than 60% by weight based on the total content of the surfactant. delete delete delete [Claim 2] The method according to claim 1, wherein the total content of the surfactant is 40 to 70 wt% based on the total weight of the sheet, and the total content of the polyvinyl alcohol or polyvinyl alcohol copolymer is 30 to 50 wt% And the like. The laundry sheet according to claim 1, wherein the number average molecular weight of the polyvinyl alcohol or polyvinyl alcohol copolymer is 20,000 to 50,000. The laundry sheet according to claim 6, wherein the number average molecular weight of the polyvinyl alcohol or polyvinyl alcohol copolymer is 20,000 to 30,000. The laundry sheet according to claim 1, wherein the polymer is polyvinyl alcohol and the degree of saponification of the polyvinyl alcohol is 80-90%. delete delete delete The polyvinyl alcohol or polyvinyl alcohol copolymer as claimed in claim 5, wherein the total content of the polyvinyl alcohol or polyvinyl alcohol copolymer in the sheet is 30 to 50% by weight based on the total weight of the sheet after drying, and the amount of the alkali metal salt of alkyl sulfate Wherein the content of the auxiliary surfactant is 30 to 60 wt%, and the total content of the auxiliary surfactant is 10 to 20 wt%. The laundry sheet according to any one of claims 1, 5 to 8, and 12, wherein the laundry sheet includes a bubble to improve water solubility. The laundry sheet according to any one of claims 1, 5 to 8, and 12, wherein the specific gravity of the laundry sheet is 0.6 to 0.9. A laundry sheet comprising a polymer, a surfactant and an alkali builder,
Wherein the polymer is a polyvinyl alcohol-based copolymer including a monomer unit having a carboxyl group,
Wherein the surfactant comprises an alkali metal salt of alkyl sulfate having 8 to 18 carbon atoms,
Wherein the alkali metal salt of alkyl sulfates having 8 to 18 carbon atoms is a main surfactant containing not less than 60% by weight based on the total content of the surfactant. [16] The method of claim 15, wherein the copolymer comprises a vinyl alcohol unit and an anionic monomer unit of the following general formula (1) or (2), wherein the content of the anionic monomer unit is 0.5-5 mol% Sheet.
&Lt; Formula 1 >

(2)

R 1, R 2, and R 3 are independently H or methyl; and n is an integer of 0-3 independently of each other. delete delete [15] The method of claim 15, wherein the total content of the surfactant is 40 to 70 wt% based on the total weight of the sheet, and the total content of the polyvinyl alcohol copolymer is 30 to 50 wt% Sheet. 16. The laundry sheet according to claim 15, wherein the polyvinyl alcohol-based copolymer has a number average molecular weight of 20,000 to 50,000. 16. The laundry sheet according to claim 15, wherein the saponification degree of the polyvinyl alcohol copolymer is 60-85%. delete The laundry sheet according to any one of claims 15 to 16, and 19 to 21, wherein the laundry sheet includes bubbles and is improved in water solubility. The laundry sheet according to any one of claims 15 to 16, 19 to 21, wherein the specific gravity of the laundry sheet is 0.6 to 0.9. The sheet according to any one of claims 1, 5 to 8, 12, 15 to 16, and 19 to 21, wherein the sheet contains starch in an amount of 0- 5% by weight based on the total weight of the composition. (S1) preparing a solution containing a polyvinyl alcohol or polyvinyl alcohol-based copolymer and an alkali metal salt of an alkyl sulfate having 8 to 18 carbon atoms in an amount of 60% by weight or more based on the total content of the surfactant;
(S2) bubbling; And
(S3). &Lt; / RTI &gt; delete delete

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