KR102392192B1 - Sheet for laundry - Google Patents

Abstract

The present invention provides a washing sheet that is completely dissolved in water and does not need to be removed after washing, has excellent washing performance, is easy to use, has storage stability, and does not cause inconvenience during use. The laundry sheet of the present invention is prepared using a polyvinyl alcohol polymer/copolymer, a main surfactant having a specific structure, and optionally an auxiliary 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. More specifically, it relates to a sheet-type or film-type detergent having a formulation different from that of a general powder detergent or liquid detergent.

So far, powder detergents or liquid detergents have been used as detergents used in washing machines. In the case of liquid detergent, there is a disadvantage that consumers are reluctant to use it because it is relatively heavy, and in the case of powder detergent, a phenomenon of powder flying occurs during use, so the need for a new type of detergent has been constantly raised.

In order to improve this problem, US Patent No. 4,605,509 discloses a technology for packaging a liquid detergent component and a fabric softener in a water-soluble film bag. However, in the case of fractional packaging using water-soluble polymer films, the seal bursts during storage or transportation of the product, resulting in leakage of the contents. In addition, the storage stability of the product was very deteriorated, such as active ingredients oozing out on the surface of the film. In addition, the water-soluble film used as a packaging material is designed to have stability against moisture in the atmosphere and durability against the contents, but it takes a considerable amount of time to dissolve at low temperatures, and the film does not dissolve completely, leaving a residue of the film. This occurred.

In addition, although a washing sheet using a liquid detergent adsorbed to the water-insoluble adsorption sheet has been developed, there is a disadvantage in that the water-insoluble adsorption sheet needs to be removed after washing.

Therefore, the problem to be solved by the present invention is to provide a washing sheet for use in a washing machine that not only dissolves completely in the washing process, but also has excellent washing performance, easy to manufacture, and secures storage stability.

In order to solve the above problems, the present invention provides a sheet-forming polymer in a laundry sheet manufactured using a sheet-forming polymer, a washing surfactant, etc., wherein the sheet-forming polymer is polyvinyl alcohol or a polyvinyl alcohol-based copolymer, There is provided a laundry sheet, characterized in that the surfactant for the cleaning effect includes a non-aromatic surfactant without an ethylene oxide group in the structure of the surfactant.

The washing film according to the present invention (1) is easily dissolved in low-temperature water and exhibits excellent washing performance, (2) liquid active ingredients do not come out of the sheet until they are put into the washing machine, and (3) when the consumer uses the It exhibits flexibility while having a tensile strength that is unbeatable, (4) has stability in circulation because it is not absorbed by moisture in the air, and (5) has excellent washing performance.

The present invention is gelatin, pectin, dextran, hyaluronic acid, collagen, agar, gum arabic, acacia gum, alginic acid, sodium alginate, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose sodium, starch, dextrin, carboxymethyl Among various polymers such as starch, polyvinylpyrrolidone, polyvinyl methacrylate, polyacrylic acid, and polyethylene oxide, it is very preferable to use polyvinyl alcohol or polyvinyl alcohol-based copolymer as a main material for forming a laundry sheet. based on discovery

That is, unlike other film-forming substrates, polyvinyl alcohol or polyvinyl alcohol-based copolymer can maintain physical properties such as tensile strength of the film even when a large amount of active ingredients such as a high content of surfactant are contained in the matrix formed thereby. It was discovered by the present inventors that it can contain a relatively large amount of surfactant per unit area within the physical property limits required for a sheet-type detergent, so that it can exhibit excellent washing performance even with the size of a tissue product such as a general wet tissue became

In the laundry sheet of the present invention, in particular, among polyvinyl alcohol or polyvinyl alcohol-based copolymers having various molecular weights and saponification degrees, film formability, solubility, manufacturing easiness, storage stability, washing performance, viscosity) and the like, a polymer having a number average molecular weight of 10,000 to 100,000 is preferable, more preferably a polymer of 20,000 to 50,000 is used, and even more preferably a polymer of 20,000 to 30,000 is used.

In addition, the degree of saponification of polyvinyl alcohol or polyvinyl alcohol-based copolymer was different for the purpose of the present invention depending on whether the polymer was a copolymer, whether an alkali builder was used, and the like. 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 contains a comonomer represented by 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%, and still 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-based copolymer comprising an anionic monomer unit having a carboxyl group, and the surfactant is a surfactant described later, preferably provides a laundry sheet comprising an alkyl sulfate salt (preferably an alkali metal salt of lauryl sulfate) having 8 to 18 carbon atoms.

The copolymer includes a vinyl alcohol monomer unit and an anionic monomer unit represented by the following formula (1) or (2), and a copolymer having an anionic monomer unit content of 0.5-5 mol% is particularly preferred.

<Formula 1>

<Formula 2>

In Formulas 1 and 2, R1, R2, and R3 are each independently H or methyl, and n is each independently an integer of 0-3.

When PVA is used as the main formulation agent, there is a problem in that it is cured by alkali builders. When polyvinyl alcohol-based copolymer is used as a film forming material instead of PVA, even if an alkali builder, one of the laundry active ingredients, is included, the formability of the film And it is possible to improve the washing efficiency of the laundry sheet without deterioration in solubility. However, as the monomer for the copolymer, not all anionic monomers were preferable, and only copolymers containing an anionic monomer having a carboxyl group were preferable for the purpose of the present invention. For example, in a PVA copolymer having an anionic monomer having -SO ₃ H, gelling occurred by an alkali builder, so that it was difficult to dissolve the sheet after the sheet was manufactured.

In addition, very specifically, in a laundry sheet containing an alkyl sulfate metal salt, an alkali builder, and a PVA copolymer, the degree of saponification of the PVA copolymer was preferably 60-90%, unlike PVA, and more preferably 70-85%. preferred, and 70-82% was even more preferred. Specifically, when the degree of saponification is too high, for example, when it exceeds 90%, the solubility of the sheet is greatly reduced after the sheet is manufactured. When the degree of saponification is too low, for example, when it is less than 60%, the water solubility of the copolymer is was lowered

In the present invention, when polyvinyl alcohol or polyvinyl alcohol-based copolymer is used as the main material of the laundry sheet, the structure of the surfactant is very specific among a wide variety of surfactants such as nonionic surfactants, anionic surfactants, and amphoteric surfactants. It is based on the unexpected and surprising discovery that the use of a non-aromatic surfactant having no ethylene oxide group therein as the main surfactant is highly desirable for the purposes of the present invention, such as film formability, cleaning performance, and stability. In particular, among the non-aromatic surfactants having no ethylene oxide group in the structure of the surfactant, an alkyl sulfate alkali metal salt having 8 to 18 carbon atoms is more preferable, an alkali metal lauryl sulfate salt is even more preferable, and sodium lauryl sulfate is the most preferable Do.

Preferably, based on the total surfactant weight, the content of the main surfactant is 50% by weight or more, more preferably 60% by weight or more, and still more preferably 70% by weight or more.

When SLES (sodium lauryl ether sulfate) or EO moiety nonionic surfactants containing a large amount of ethylene oxide groups in the surfactant structure are used as main surfactants, the film-forming ability is greatly reduced. This is thought to be the cause of the low solubility of polyvinyl alcohol in water due to the property of attracting water molecules of the ethylene oxide structure itself, and the deterioration of the physical properties of the laundry sheet, but the present invention is limited to these theoretical assumptions. not.

In addition, in the case of a surfactant having an aromatic group, such as LAS (linear alkylbenze sulphonate), when a sheet is prepared together with polyvinyl alcohol, film-forming ability and storage stability are very poor. When a surfactant containing an aromatic group is used as the main surfactant, good film properties do not appear due to poor compatibility with polyvinyl alcohol or polyvinyl alcohol-based copolymer used as a film-forming substrate.

Accordingly, more preferably, the present invention provides a laundry sheet containing a polyvinyl alcohol polymer/copolymer and a surfactant, wherein the surfactant has no ethylene oxide group in the structure and preferably contains a non-aromatic surfactant. , There is no such ethylene oxide group, and the non-aromatic surfactant is the main surfactant, meaning that it contains 50% by weight (more preferably 60% by weight, even more preferably 70% by weight) or more relative to the total content of the surfactant. more preferably.

Non-aromatic ethylene oxide group-free surfactants used as the main surfactant include alkylsulfate salts of RSO ₄ ^- M ⁺ (M is an alkali metal, preferably sodium or potassium, most preferably sodium), α- Olefin sulfonates, alkali metal salts of alkanesulfonates (preferably sodium salt), fatty acid methyl ester sulfonates alkali metal salts (preferably sodium salt), fatty acids, alkyl glycosides, etc. can be used, and alkyl sulfate salts are particularly preferred in the present invention. is preferred for several purposes, and especially surprisingly sodium lauryl sulfate is more preferred for several purposes such as the formability of the film of the present invention. The carbon number of the alkyl or alkane included in the non-aromatic ethylene oxide group-free surfactant structure is preferably C8 to C18, and the fatty acid preferably has C8 to C18 carbon atoms.

Without being limited by theory, in the case of an alkyl sulfate surfactant containing saturated hydrocarbons of C8-C22 to C8-C18, more preferably C12-C16, polyvinyl alcohol polymer/copolymer as a film-forming substrate It is assumed that washing performance can be improved while forming a sheet formulation having good strength even if a high content of surfactant is included due to excellent compatibility with the present invention, but the present invention is not limited to this theoretical assumption.

Manufactured using a polyvinyl alcohol polymer/copolymer and a surfactant (a non-aromatic surfactant having no ethylene oxide group as the main surfactant accounting for 50 wt% or more of the surfactant, more preferably 60 wt% or more) In the case of the washed laundry sheet, the total content of the surfactant (after drying) is 30 to 80% by weight (more preferably 40 to 70% by weight) based on the total weight of the sheet, and the content of the polyvinyl alcohol polymer/copolymer is the total amount of the sheet. It is preferably 20 to 50% by weight (more preferably 30 to 50% by weight, even more preferably 35 to 50% by weight) based on the weight.

As shown in the experimental results to be described later, when the polyvinyl alcohol polymer/copolymer content is less than 35% by weight, the sheet has good physical properties, that is, strength, but there is a risk that surfactant components may come off depending on storage conditions, and if the content is less than 30%, In this case, in addition to the above problem, the strength of the sheet is significantly reduced, which may cause problems in use.

Such a laundry sheet may include other additives such as fluorescent dyes and enzymes, which will be described in detail below, in addition to the polyvinyl alcohol polymer/copolymer and surfactant. When the content of the surfactant is lower than the above range, washing performance is deteriorated, and when the content is higher than the content, the content of polyvinyl alcohol or polyvinyl alcohol-based copolymer is relatively reduced, making it difficult to prepare a sheet formulation.

Preferably, the present invention provides a laundry sheet containing a polyvinyl alcohol polymer/copolymer and a surfactant, wherein the surfactant is

(a) as the main surfactant, there is no ethylene oxide group in the structure, and is a non-aromatic surfactant (more preferably, an alkylsulfate salt of 8-18 carbon atoms having the formula RSO ₄ ^- M ⁺ (M is an alkali metal, preferably is sodium or potassium, most preferably sodium), even more preferably sodium alkylsulfate, most preferably sodium lauryl sulfate, and

(b) provides a laundry sheet comprising heptaoxyethylated lauryl alcohol (LA7), nonaoxyethylated lauryl alcohol (LA9), or a mixture thereof, which are auxiliary surfactants.

The present invention also relates to a laundry sheet manufactured using polyvinyl alcohol or a polyvinyl alcohol-based copolymer and a surfactant as a laundry active ingredient, as the main surfactant, there is no ethylene oxide group in the structure, and is a non-aromatic surfactant (more preferably Preferably, an alkyl sulfate salt having 8 to 18 carbon atoms, more preferably sodium alkyl sulfate, and most preferably sodium lauryl sulfate) is used, and a nonionic surfactant LA7 or LA9 (preferably LA7) is used as a cosurfactant. It is based on the surprising finding that cleaning performance can be greatly improved while maintaining film formability when using Surprisingly, only LA7 or LA9 did not significantly degrade the film formability or improved the cleaning performance when other surfactants with good cleaning performance were mixed into the polyvinyl alcohol polymer/copolymer and lauryl sulfate salt system.

Accordingly, the present invention also preferably provides, in the laundry sheet of the present invention, as surfactants, only lauryl sulfate salt (most preferably sodium salt) and LA7/LA9 (preferably LA7), which are the main surfactants, as surfactants. It provides a sheet for washing manufactured using the.

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

When the auxiliary surfactant LA7 or LA9 is mixed in too much, there is a fear that it seeps into the sheet and deteriorates the properties of the sheet and makes handling difficult.

As a result, the present invention is the polyvinyl alcohol or polyvinyl alcohol-based copolymer; RSO ₄ ^- M ⁺ as the main surfactant, an alkyl sulfate salt having 8 to 18 carbon atoms represented by M + (M is an alkali metal, preferably sodium or potassium, most preferably sodium) (preferably sodium alkyl sulfate, more preferably sodium lauryl sulfate); And in the laundry sheet prepared using the auxiliary surfactant LA7, LA9 or a mixture thereof, the content of the polyvinyl alcohol or polyvinyl alcohol-based copolymer is 30 to 50% by weight based on the total weight of the sheet after drying, The content of the lauryl sulfate salt, which is 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 the formulations of the present invention, it is preferable not to substantially use starch as a formulation agent (film-forming substrate). As starch was mixed and used as a formulation, that is, as starch was included as a component of the sheet, the surfactant floated after drying (poor compatibility), and the strength of the sheet decreased as the starch content increased. In addition, the solubility also decreased as the starch content increased.

Substantially not used in the present invention means 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, even more preferably not at all, based on the dry weight of the sheet.

The laundry sheet according to the present invention includes: a fluorescent whitening agent; enzymes (eg, cellulases, proteases, etc.); Alkali builders (e.g. sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium metasilicate, alkali sodium silicate, neutral sodium silicate, sodium tripolyphosphate, sodium pyrophosphate, sodium borate, zeolite (sodium aluminosilicate), sodium sesquicarbonate , MEA, TEA); disintegrants/adjuvants (eg, starch, cellulose derivatives, sodium chloride, citric acid, glycerin, propylene glycol); fabric softeners (eg, quaternary ammonium salt-based cationic surfactants, silicone fabric softeners); bleach (eg, perborates, percarbonates, superphosphates, diacyls, tetraacylperoxides); dispersants/emulsifiers (eg, polyoxy alkylene alkyl phenyl ethers, polyoxy alkylene alkyl ethers, polyoxy ethylene polyoxy propylene block polymers); disinfectants/disinfectants (eg sodium hypochlorite, hydrogen peroxide, urea peroxide); Spices; antiseptic; pigment; Antibacterial agents and the like may be further included .

The thickness of the laundry sheet according to the present invention is preferably 1 μm to 1 cm, more preferably 5 μm to 0.5 cm, and most preferably 50 μm to 1 mm. If the thickness of the dried laundry sheet is less than 1 ㎛, the supporting of the active ingredient is insufficient, the strength of the film is weak, and it is difficult to obtain the desired performance. This may decrease.

More preferably, the present invention relates to 20 to 50% by weight of PVA (preferably 30 to 50% by weight), 30 to 50% by weight of SLS, 10 to 20% by weight of LA7/9, optionally fluorescence, relative to the total weight of the sheet after drying. Provided is a sheet-type water-soluble laundry detergent comprising 1 to 5% by weight of a whitening agent, and optionally 1 to 5% by weight of an enzyme. The sheet-type laundry detergent of the present invention is completely dissolved when used with clothes in a washing tub, so there is no need for a removal process.

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

The laundry sheet according to the present invention may also include the above-mentioned polyvinyl alcohol or polyvinyl alcohol-based copolymer; And, in addition to the main surfactant, an aromatic surfactant may be further included as an auxiliary surfactant within the scope not impairing the object of the present invention, and an alkylbenzenesulfonate may be used as the aromatic surfactant, and the alkylbenzenesulfonate The alkyl of is preferably a linear alkyl having 8 to 18 carbon atoms.

The laundry sheet of the present invention may be used in a state in which two or more layers are integrated by stacking sheets of other layers in addition to the one-layer sheet according to the present invention.

The laundry sheet according to the present invention is prepared by dissolving polyvinyl alcohol or a polyvinyl alcohol-based copolymer in an appropriate amount of water to prepare a polyvinyl alcohol polymer/copolymer solution, then mixing other ingredients such as a surfactant well, and then mixing it with a certain thickness It can be prepared by drying after making a sheet of. In addition, before dissolving polyvinyl alcohol or polyvinyl alcohol-based copolymer in water, other components such as a surfactant may be first dissolved. The laundry sheet of the present invention is not limited to the above manufacturing method.

The present invention is also based on the fact that it is preferable to further include a bubbling process during the manufacturing process in order to improve the water solubility of the sheet of the present invention, and through this bubbling process, the washing sheet according to the present invention When the specific gravity is adjusted to 0.6 to 0.9, various advantages for washing such as water solubility and water dissolution speed of the sheet may be further emphasized. Therefore, the present invention comprises the steps of preparing a solution containing polyvinyl alcohol or a polyvinyl alcohol-based copolymer and a surfactant; bubbling; And it provides a method of manufacturing a sheet for laundry comprising the step of drying.

Accordingly, the present invention also provides a laundry sheet having the above-mentioned technical characteristics, and having a specific gravity of 0.6 to 0.9 added thereto.

The present invention is a laundry sheet prepared by using polyvinyl alcohol or a polyvinyl alcohol-based copolymer as a polymer and containing a surfactant, wherein the surfactant includes an alkyl sulfate alkali metal salt having 8 to 18 carbon atoms, Alkyl sulfate alkali metal salt of 8-18 provides a laundry sheet which is a main surfactant containing 60 wt% or more based on the total content of the surfactant.

The total content of the surfactant is 40 to 70% by weight based on the total weight of the sheet, and the total content of polyvinyl alcohol or polyvinyl alcohol-based copolymer is 30 to 50% by weight based on the total weight of the sheet.

The number average molecular weight of the polyvinyl alcohol or polyvinyl alcohol-based copolymer provides a laundry sheet of 20,000-50,000.

The number average molecular weight of the polyvinyl alcohol or polyvinyl alcohol-based copolymer provides a laundry sheet of 20,000-30,000.

The polymer is polyvinyl alcohol, and the saponification degree of polyvinyl alcohol provides a laundry sheet of 80-90%.

The total content of polyvinyl alcohol or polyvinyl alcohol-based copolymer in the sheet is 30 to 50% by weight based on the total weight of the sheet after drying, and the content of alkali metal salt of alkylsulfate having 8 to 18 carbon atoms as the main surfactant is 30 to 60% by weight %, and the total content of the auxiliary surfactant is 10 to 20% by weight.

The laundry sheet provides a laundry sheet with improved water solubility, including bubbles.

The specific gravity of the laundry sheet provides a laundry sheet of 0.6 to 0.9.

The present invention relates to 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, and the surfactant is an alkyl sulfate alkali having 8 to 18 carbon atoms. It includes a metal salt and provides a laundry sheet, which is a main surfactant containing at least 60% by weight of an alkyl sulfate alkali metal salt having 8 to 18 carbon atoms relative to the total content of the surfactant.

The copolymer includes a vinyl alcohol unit and an anionic monomer unit represented by the following Chemical Formula 1 or 2, and the content of the anionic monomer unit is 0.5-5 mol%.

<Formula 1>

<Formula 2>

In Formulas 1 and 2, R1, R2, and R3 are each independently H or methyl, and n is an integer of 0-3 independently of each other.

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-based copolymer is 30 to 50 wt% based on the total weight of the sheet.

The number average molecular weight of the polyvinyl alcohol-based copolymer provides a laundry sheet of 20,000-50,000.

The degree of saponification of the polyvinyl alcohol copolymer provides a laundry sheet of 60-85%.

The laundry sheet provides a laundry sheet with improved water solubility, including bubbles.

The specific gravity of the laundry sheet provides a laundry sheet of 0.6 to 0.9.

The sheet provides a laundry sheet comprising 0-5% by weight of starch based on the dry weight of the sheet.

(S1) preparing a solution containing polyvinyl alcohol or polyvinyl alcohol-based copolymer and an alkyl sulfate alkali metal salt having 8 to 18 carbon atoms in an amount of 60 wt % or more based on the total content of the surfactant;

(S2) bubbling (bubbling); and

(S3) It provides a method of manufacturing a laundry sheet comprising the step of drying.

The present invention provides a washing sheet that is completely dissolved in water and does not need to be removed after washing, has excellent washing performance, is easy to use, has storage stability, and does not cause inconvenience during use.

1 is an experimental result showing the change in sheet tensile strength according to PVA molecular weight, PVA content, and water content compared to solid content. In the X-axis value "03-40-170" of FIG. 1, the first number means the degree of polymerization/100 (that is, 03 means the degree of polymerization 300), the second number means the content (wt%) of PVA, , the third number means the water content (wt%) relative to the solids. The PVA molecular weight is approximately 50 times the degree of polymerization. The Y-axis value means tensile strength, and the unit is kgf/cm ² .
2 is a result showing the change in tensile strength caused by substituting starch for a part of PVA used as a formulation agent. The Y-axis value of the graph means the tensile strength, and the unit is kgf/cm ² . The red line in FIG. 2 is a boundary line showing the minimum tensile strength required in terms of sheet usability (if it is less than that, it is easily torn or broken) of 5 kgf/cm ² .
3 is a graph showing the change in viscosity as the molecular weight of PVA increases in a specific content condition. At this time, the water content standard of each blending solution is 240% of the solid content.

Hereinafter, examples and the like will be described in detail to help the understanding of the present invention. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the following examples. The embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art.

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

Film formability, solubility, storage stability, etc. of the polymer were evaluated while manufacturing a laundry sheet using various polymers according to 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. After placing the polymer solution or suspension on the release film, it was prepared to a predetermined thickness using a film applicator of Elcometer and dried in a drying oven at 115° C. for 10 minutes to prepare a laundry sheet (thickness: 0.01 cm). Using the sheet formation process and the sheet formed after manufacturing, the film formability was evaluated in three stages: excellent, normal, and poor.

Solubility was evaluated as follows. The prepared film sheet was cut into 5 cm × 5 cm, and about 300 ml of purified water at 15° C. was put into 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: good (within 3 minutes), normal (3 minutes - 5 minutes), and poor (more than 10 minutes).

film formulation Solubility Other evaluation polyvinyl alcohol Great Great Good water solubility polyacrylic acid usually Great In high pH, neutralized state, it dissolves well in water, but the formed film is brittle. polyethylene glycol error usually - polyacrylamide error Great - polyvinylpyrrolidone Great Great Good solubility 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 aminoehtyl methacrylate, HEA means hydroxy ethyl acrylate, HEC means hydroxyethylcellulose, HPMC means hydroxypropylmethylcellulose it means.

As shown in Table 1, polyvinyl alcohol was the most preferred polymer for preparing the laundry sheet in terms of film formability, solubility of the prepared sheet, ease of manufacture, storage stability, etc. for preparing the laundry sheet. .

<Example 2> Evaluation of effects according to the content and molecular weight of PVA

In addition, as a result of evaluating film formability, solubility, manufacturing easiness, storage stability, following washing performance, process (viscosity of the formulation), etc. using polyvinyl alcohol having various molecular weights and saponification degrees, the number average molecular weight was 10,000 to 100,000 Phosphorus polyvinyl alcohol or polyvinyl alcohol copolymer is preferable, more preferably a polymer having a molecular weight of 20,000 to 50,000 is used, and even more preferably, considering the relationship with the content used, the molecular weight is from 20,000 to 20,000 for the purpose of the present invention. PVA of 30,000 or a copolymer thereof is preferred. In addition, in terms of the degree of saponification, when alkali builders are not mixed, it is preferable that the polymer has a degree of saponification of 80-90%, and when using a PVA copolymer and mixing alkali builders, the degree of saponification is 60-90% (more It is particularly preferred to use a polymer that is preferably 70-85%, even more preferably 70-82%). In the case of having a saponification degree in a range lower than the saponification degree, there was a problem in that water solubility was lowered, and when a polymer having a saponification degree in a range higher than the saponification degree was used, a gelling phenomenon was a problem.

Specific experimental results showing the above contents are shown in Tables 3 and 4 below. Preparation and evaluation of the sheet were performed similarly to Example 1. At this time, the casting conditions were 1100 μm (mixture coating thickness), and the drying conditions were 115° C. for 15 minutes. Film properties ("surface after drying") including a smearing scale were evaluated by scoring. For example, a point of 1 indicates that there is no abnormality in the film but is smeared on the surface, and a point of 3 indicates that a phase separation phenomenon occurs on the surface of the film and is smeared on the surface. The evaluation criteria for solubility and tensile strength were shown in Table 2 below.

Evaluation results very good Great usually error 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

If the content of the polymer fluctuates, the total solid content (PVA, SLS, LA7, etc.) was adjusted to 100% by supplementing or reducing surfactants (SLS, LA7), and the amount of other ingredients (fluorescent brightener, enzyme, fragrance, etc.) The content was fixed at 5% by weight. As a basic formulation, 40% by weight of PVA, 45% by weight of SLS, 10% by weight of LA7 and 5% by weight of other ingredients (prescription number 1) were used. In the table below, the PVA content means the weight % of the PVA in the total solids excluding water, and the water content means the weight % of water relative to the total weight of the solids when preparing the formulation solution. That is, in Formula 1, the PVA content of 40% means that 40% by weight of PVA is included in the total solid content, and the water content of 63% means that the solid content is 37% in the formulation for manufacturing the sheet, and the water is 63%. Therefore, when the solid content is 100, it means that the water content is about 170.

* In case of prescription No. 13, drying time was added by 2 minutes.

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 sheet formability and strength can be secured by increasing the PVA content in the sheet, but because the active ingredient content is lowered, the washing performance is lowered.

On the other hand, as the molecular weight increased, the sheet surface became stable (compatibility improved) and the sheet strength increased. Therefore, the higher the molecular weight, the better the sheet formability can be secured at a low PVA content, but the viscosity of the blending solution is too high, so it is difficult to actually secure fairness suitable for mass production. On the other hand, in order to improve this, that is, to lower the viscosity, it can be produced by increasing the water content, but there is a problem in that the productivity is greatly reduced.

Therefore, as a result, the number average molecular weight of PVA or its copolymer used in terms of sheet strength and compatibility with laundry active ingredients is preferably 20,000 or more. In addition, in terms of the manufacturing process, since 5,000 cps or less is appropriate at a certain PVA content (about 30%) and water content (240 wt% relative to solid content), the number average molecular weight of PVA or its copolymer is preferably 50,000 or less, and 30,000 The following were more preferable.

In this regard, when a sheet is prepared 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 sheet solid content, the molecular weight of PVA increases. The viscosity of the polymer solution, which was changed while doing so, was measured and the results are shown in FIG. 3 . In the case of a polymer solution used during the manufacturing process, it is undesirable if the viscosity is too high or too low. In the case of a polymer solution having the same kinds of components as in the present invention, it was found that the viscosity increased rapidly from a molecular weight of about 50,000.

For reference, the measurement results of changes in sheet tensile strength according to molecular weight, PVA content, and water content compared to solid content are shown in FIG. 1 . In terms of sheet usability, a minimum of 5 kgf/cm ² (if less than that, it is easily torn or broken) is required, and if it is 10 kgf/cm ² or more, it was judged to be a good level, but in terms of tensile strength, for example, 05-40-170 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, etc. were preferable.

<Example 3> Selection and evaluation of main surfactant

A cleaning sheet was prepared according to the components and contents shown in Table 5 below, and the film formability and cleaning performance of the prepared sheet were comparatively evaluated.

number ingredient Content (unit %) One polyvinyl alcohol (PVA) 40% 2 Surfactants of Table 3 below 55% 3 Fluorescent brightener 2 % 4 enzyme 1.5% 5 incense and others 1.5%

Specifically, 145 g of PVA (saponification degree: 86.5%, average degree of polymerization: 500) was added to 630 g of distilled water and then dissolved at 80° C. for 2 hours to prepare a PVA solution. After adding the remaining components of Table 2 to the prepared PVA solution, they were mixed using a mechanical stirrer. After putting the mixed solution on the release film, it was prepared to a certain thickness using Elcometer's film applicator, and then dried in a drying oven at 115° C. for 10 minutes to prepare a PVA sheet containing a surfactant, a washing component.

Table 6 below shows the evaluation results of film formability, cleaning performance, etc. according to the type of surfactant. Film formability was evaluated in the same manner as in Example 1 in three stages: excellent, normal, and poor. The cleaning performance was evaluated by the method presented below, and when the cleaning power was 60% or more based on Japanese soiled cloth, it was judged as excellent, when it was 50-59%, it was normal, and when it was less than 50%, it was judged as bad.

Specifically, the cleaning power was evaluated using a washing machine under the same conditions, and general tap water was used as the washing water. In addition, cold water was used for the washing temperature, and the same cold water was used under the conditions used in general households, and EMPA 116, an artificial wet-stained cloth and protein-contaminated cloth manufactured by the Japan Laundry Science Association, was used for the soiled cloth used for the evaluation of the cleaning power. In addition, the stained cloth was evaluated by attaching it to an actual cotton T-shirt. In addition, 16 sheets of 5 cm × 5 cm stained cloth were used for comparative evaluation by a statistical method. At this time, the _WB value, which is a value indicating the whiteness of the stained fabric, was measured using a colorimeter before and after washing. The laundry sheet prepared in the above example was cut to a size of 20 cm × 15 cm, and two cut detergents were used. At the beginning of washing, each of the laundry sheets prepared in Examples was put together with the soiled cloth, and the washing conditions were performed at medium water level in the standard course of the washing machine (washing 20 minutes, rinsing twice), and the dehydrated soiled cloth was placed in a constant temperature and humidity room ( 25°C, 20%RH) for 1 day, ironing was performed, and the WB value was measured with the same colorimeter. The cleaning power was calculated by substituting the obtained result into the Kubelka Munch equation expressed by Equation 2 below, and the results are shown in Table 6 below.

In Equation 1, Rs represents the surface reflectance of the stained cloth, Rc represents the surface reflectance of the stained cloth after the washing process, and Ro represents the surface reflectance of the white comedon.

Kinds designation film formulation cleaning performance note nonionic surfactant LA5 (pentaoxyethylated lauryl alcohol)
(Polyoxyethylene Lauryl Ether) error usually liquid LA7 (heptaoxyethylated lauryl alcohol) error Great liquid LA9 (nonaoxyethylated lauryl alcohol) error Great liquid LC7 (Laureth-7-citrate) error usually liquid CA7 (Polyoxyethylene cetyl ether) error usually semi-solid CA9 error 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 error elegance anionic surfactant SLES 2 (sodium laureth sulfate) error Great 70% solution SLES 3 error Great 70% solution SLS (sodium lauryl sulfate) Great Great elegance SAS (Sodium alkanesulfonate) error usually 25% solution ALS (Ammonium Lauryl Sulfate) error usually 26% solution Alpha Olefin sulfonate (AOS) error Great 35% solution ALES 3mol (Ammonium Laureth Sulfate) error Great 30% solution LAS (linear alkylbenze sulphonate)-MEA (mono ethanol amine) error usually semi-solid LAS-Na (Soduim linear alkylbenze sulphonate) error usually semi-solid Lauric acid-K (Potassium Laurate) error error elegance Myristic acid-K (Potassium Myristrate) error usually elegance MES (methyl ester sulfonate) error usually elegance amphoteric surfactant amine-oxide error error 30% solution Cocamidopropyl Betaine usually error elegance

As shown in Table 6, very surprisingly, when polyvinyl alcohol was used as a polymer substrate, only sodium lauryl sulfate (SLS) had excellent film formability, and various other cleaning surfactants had moderate or poor film formability. did For example, surfactants such as LAS, SLES, and MEA did not have good compatibility with PVA due to phase separation during the manufacturing process. .

<Example 4> Selection and evaluation of auxiliary surfactants

* Using sodium lauryl sulfate as the main surfactant and various nonionic surfactants as auxiliary surfactants, various laundry sheets were prepared and evaluated according to the prescription in Table 7 below. Laundry sheets were prepared in a manner similar to Example 3 above.

item Example a b c d e f g h It's j k polymer
matrix PVA ⁽¹⁾ 40 40 40 40 40 40 40 40 40 40 40 non-ion
Surfactants LA5 15 - - - - - - - - - - LA7 - 15 - - - - - - - - - LA9 - - 15 - - - - - - - - LC7 - - - 15 - - - - - - - CA7 - - - - 15 - - - - - - CA9 - - - - - 15 - - - - - CA15 - - - - - - 15 - - - - SA14 - - - - - - - 15 - - - OA14 - - - - - - - - 15 - - AG200 - - - - - - - - - 15 - C-MEA - - - - - - - - - - 15 negative ions
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 others 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⁾ means polyvinyl alcohol having a degree of saponification of 86.5% and an average degree of polymerization of 500, SLS ⁽²⁾ is sodium lauryl sulfate, and as a fluorescent dye ⁽³⁾ , Tinopal CBS-X (Civa Specialty) chemical) was used.

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

Film tensile strength was evaluated as follows. The test method followed the ISO 527-3 standard test method, and a Zwick 1120 universal testing machine was used. After each sample was prepared to have a constant thickness of 0.2 mm, cut into 2×10 (cm ² ), the specimen was held with a screw grip, the distance between grips was maintained at 50 mm, and a tension test was performed at a speed of 20 mm/min. did The point at which the film was cut without overcoming the force was determined as the tensile strength, and the numerical values in Table 8 below were taken as a reference in consideration of ease of use.

Evaluation results very good Great usually error 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 It's j k Cleaning power (%)
(Japanese Laundry Science Association Contaminated Fabric) 60 71 70 64 58 66 64 67 62 68 58 Cleaning power (%)
(protein-contaminated cloth, EMPA 116) 66 68 67 68 64 66 65 68 60 62 56 Solubility ◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ○ ○ The tensile strength ○ ◎ ◎ ○ ◎ ◎ ◎ ◎ ○ ○ ◎

As shown in Table 9, overall, 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> Impact evaluation according to the content of SLS as the main surfactant and LA7 as the auxiliary surfactant

As shown in Table 10 below, as shown in the components and contents, a laundry sheet was prepared while changing the contents of the main surfactant SLS and the auxiliary surfactant LA7. The preparation method was the same as in Example 4.

Ingredients/content (wt%) 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% Enzyme (Savinase-16L, Novozyme) 1.5% 1.5% 1.5% 1.5% 1.5% 1.5% incense and others 1.5% 1.5% 1.5% 1.5% 1.5% 1.5% Sum 100% 100% 100% 100% 100% 100%

The film formability, washing performance, etc. of the thus prepared laundry sheet were evaluated in the same manner as in Example 4, and are shown in Table 11 below.

Sample film formulation Cleaning performance (%) Japanese pollution gun EMPA116 Example 5-1 Great 65 55 Example 5-2 Great 67 58 Example 5-3 Great 69 62 Example 5-4 Great 71 68 Example 5-5 usually 72 66 Example 5-6 error 68 60

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

<Example 6> Comprehensive evaluation

Various aspects were evaluated by preparing a water-soluble sheet with the prescription and content of Table 12 below. The preparation method was the same as in Example 4.

item Example comparative example a b c d e f g h It's j k l a b c polymer
matrix PVA 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 non-ion
Surfactants LA7 0 5 10 15 20 25 15 15 15 15 - - 55 - - negative ions
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 others 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 PVA, polyoxyethylene alkyl ether LA7 was used as a nonionic surfactant, AOS means α-olefin sulfonate, and a fluorescent dye Tinopal CBS-X (Civa Specialty Chemicals) was used as the method.

Sheet formulation evaluation

Formulation properties of the water-soluble sheet detergents prepared in Comparative Examples and Examples were evaluated according to the following criteria through visual observation, etc., and the results are shown in Table 13 below.

◎: The sheet formulation is flexible and excellent without any smearing phenomenon

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

△: Insufficient sheet flexibility, a phenomenon that a little smearing occurred

×: The sheet formulation is not available, and a lot of liquid components are smeared.

Example comparative example a b c d e f g h It's j k l a b c sheet formulation ◎ ◎ ◎ ◎ ○ △ ○ ○ △ △ ◎ ◎ × △ ×

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

Solubility and tensile strength evaluation

The washing sheets prepared in Examples and Comparative Examples were tested in the same manner as in Example 4 to evaluate solubility and tensile strength. The writing results are shown in Table 14 below.

Example comparative example a b c d e f g h It's j k l a b c Solubility ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ ◎ - ○ - The tensile strength ◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ △ ◎ ◎ - △ -

In Comparative Examples a and c, it was impossible to measure solubility and tensile strength because a sheet formulation was not formed.

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

cleaning power evaluation

The cleaning power of the laundry sheets prepared in Examples and Comparative Examples that can be prepared as laundry sheets by the following method was evaluated (in Comparative Examples a and c, the same amount of active ingredient formulation was evaluated instead of the water-soluble detergent sheet).

Specifically, the cleaning power was evaluated using a washing machine under the same conditions, and general tap water was used as the washing water. In addition, cold water was used for the washing temperature, and the same cold water was used under the conditions used in general households, and EMPA 116, an artificial wet-stained cloth and protein-contaminated cloth manufactured by the Japan Laundry Science Association, was used for the soiled cloth used for the evaluation of the cleaning power. In addition, the stained cloth was evaluated by attaching it to an actual cotton T-shirt. In addition, 16 sheets of 5 cm × 5 cm stained cloth were used for comparative evaluation by a statistical method. At this time, the WB value, which is a value indicating the whiteness of the stained fabric, was measured using a colorimeter before and after washing. The laundry sheet prepared in the above example was cut to a size of 20 cm × 15 cm, and two cut detergents were used. At the beginning of washing, the laundry sheet and detergent were put together with the dirty cloth, respectively, and the washing condition was performed at medium water level in the standard course of the washing machine (washing 20 minutes, rinsing twice), and the dehydrated contaminated cloth was placed in a constant temperature and humidity room (25℃ , 20%RH) for 1 day, ironed, and the _WB value was measured with the same colorimeter. The obtained result was substituted into the same Kubelka Munch equation as in Example 3 to calculate the cleaning power. The results are shown in Table 15 below.

Example comparative example a b c d k l a b c Cleaning power (%)
(Japanese Laundry Science Association Contaminated Fabric) 65 67 69 71 55 58 72 64 60 Cleaning power (%)
(protein-contaminated cloth, EMPA 116) 55 58 62 68 52 50 48 66 62

As shown in Table 15 above, in Examples a, b, c, d, k and l having appropriate sheet formability, solubility and tensile strength, a nonionic surfactant polyoxyethylene alkyl ether was contained in an amount of 15 wt% Example d had the best cleaning performance.

<Example 7> Stability (hygroscopicity) evaluation

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

1 month later after 2 months note dry residue film condition dry residue film condition room temperature 96% Good 96.5% Good The moisture in the sheet dries out, making the sheet brittle, but there is no significant difference in solubility. 50 degrees 97% Good 97.5% Good Freeze/Thaw
(cycle: -15~50℃) 95.5% Good 96% Good Almost no change from the initial state. 30 degrees, 80% humidity 94.5% Good 94% Good There is a slightly damp feeling, but it does not stick to the 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% by weight and the moisture content was 5% by weight, and the dried residue was measured after drying at 105° C. for 10 minutes using a halogen moisture analyzer.

As shown in Table 16, in spite of being a water-soluble sheet detergent, stability as a product could be secured under various conditions including high temperature and high humidity during the rainy season.

<Example 8> PVA copolymer use evaluation

A laundry sheet was prepared according to the prescription in Table 17, and the manufacturing method was the same as in Example 4.

item Example a b c d e f g h It's polymer
matrix PVA ⁽¹⁾ 40 40 - - - - - - - PVA copolymer ⁽²⁾ - - 40 40 40 40 40 40 40 non-ion
Surfactants LA7 15 13.5 15 14.3 13.6 13.0 12.3 11.6 10.9 negative ions
Surfactants SLS ⁽³⁾ 40 36.4 40 38.2 36.4 34.5 32.7 30.9 29.1 additive builder ⁽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 others 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 saponification degree of 86.5% and an average degree of polymerization of 500, and PVA copolymer ⁽²⁾ is vinyl alcohol (98 mol%, saponification degree: about 77 mol%)-methacrylic acid ( 2 mol%) copolymer having an average degree of polymerization of 500 was used, SLS ⁽³⁾ was sodium lauryl sulfate, builder ⁽⁴⁾ was sodium carbonate (soda), and fluorescent dye ⁽⁵⁾ was Tinopal CBS-X. (Civa Specialty Chemical) was used.

The prepared 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 It's Cleaning power (%)
(Japanese Laundry Science Association Contaminated Fabric) 71 64 70 70 72 71 68 66 64 Cleaning power (%)
(protein-contaminated cloth, 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 hardened and solubility and physical properties are remarkably reduced, and the cleaning performance also does not show the builder effect due to insoluble components. However, when using the PVA-copolymer, curing does not occur even if the builder is added, and the cleaning power is improved by the builder. In addition, when the amount of builders was 7.5% or more, the sheet strength was decreased due to a large amount of builders in the film.

<Example 9> Evaluation of the effect of the addition of starch

A sheet having a prescription as shown in Table 19 was prepared, and the effect of the addition of starch was evaluated while using PVA, starch, or a mixture thereof as a formulation. The results were evaluated as in the experiment of Example 2 and summarized in Table 20 below, and the tensile strength of the results of Table 20 is shown in FIG. 2 .

Raw material content One formulating agent 40% 2 SLS 45% 3 LA7 10% 4 etc 5% water 170 (sheet solids 100)

formulating agent
PVA/starch
(total 40%) Casting after drying
surface Solubility The tensile strength
(kgf/cm ² ) note A 1/0 Good Good ◎ 10.7 (○) B 3/1 Good Floating phenomenon (3 points) X (Hazy) 6 (△) Starch powder settles 3/1 (starch gelatinization) Good Floating phenomenon (3 points) ◎ 5.3 (△) C 2/1 Good Floating phenomenon (4 points) X (Hazy) 4.1 (X) Starch powder settles 2/1 (starch gelatinized) Good Floating phenomenon (4 points) ◎ 4.1 (X) D 1/1 Good Floating phenomenon (4 points) X (Hazy) 2 (X) Starch powder settles 1/1 (starch gelatinized) Good Floating phenomenon (4 points) Δ 2.1 (X) a little bit of debris left

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

Claims (8)

In the laundry sheet prepared by using polyvinyl alcohol or polyvinyl alcohol-based copolymer as a polymer and containing a surfactant,
The total content of polyvinyl alcohol or polyvinyl alcohol-based copolymer is 20 to 50% by weight based on the total weight of the sheet, The surfactant is a laundry sheet embedded in a polymer matrix formed by mixing a polymer and a surfactant together,
The surfactant comprises sodium lauryl sulfate (SLS),
The laundry sheet is a sheet having a thickness of 50 μm to 1 cm, and includes bubbles,
The laundry sheet is a laundry sheet, characterized in that it contains starch in an amount of 5% by weight or less based on the dry weight of the laundry sheet. delete The laundry sheet according to claim 1, wherein the polyvinyl alcohol or polyvinyl alcohol-based copolymer has a number average molecular weight of 20,000-50,000. The laundry sheet according to claim 1, wherein the sodium lauryl sulfate (SLS) is a main surfactant containing 50% by weight or more based on the total content of the surfactant. The laundry sheet according to claim 1, wherein the sheet further comprises an auxiliary surfactant in addition to sodium lauryl sulfate (SLS). The laundry sheet according to claim 5, wherein the auxiliary surfactant further comprises heptaoxyethylated lauryl alcohol (LA7), nonaoxyethylated lauryl alcohol (LA9), or a mixture thereof. delete The laundry sheet according to claim 1 or 5, further comprising at least one selected from alkali builder, fragrance, enzyme, and color.

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