KR20240032774A - Sheet for laundry - Google Patents

Abstract

The present invention provides a laundry sheet that is not only completely soluble in water and does not need to be removed after washing, but also has excellent cleaning performance, is easy to use, ensures storage stability, and causes no inconvenience during use. The laundry sheet of the present invention is manufactured using a polyvinyl alcohol polymer/copolymer, a main surfactant of 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 used in a washing machine. More specifically, it relates to sheet-type or film-type detergents that are different from general powder detergents or liquid detergents.

Until now, detergents used in washing machines have been powder detergents or liquid detergents. Liquid detergents have the disadvantage that consumers are reluctant to use them because they are relatively heavy, and powder detergents tend to scatter powder when used, so the need for new types of detergents has been constantly raised.

To improve this problem, U.S. Patent No. 4,605,509 discloses a technology for packaging liquid detergent ingredients and fabric softener in a water-soluble film bag. However, in the case of fractional packaging using water-soluble polymer films, a phenomenon occurred in which the seal bursts and the contents leak during storage or transportation of the product. In addition, the storage stability of the product was greatly reduced, with active ingredients seeping through the surface of the film. In addition, water-soluble films used as packaging materials are designed to be stable against moisture in the atmosphere and durable against the contents, but as a result, it takes a considerable amount of time to dissolve at low temperatures, and film residues remain as they are not completely dissolved. This occurred.

In addition, laundry sheets have been developed that use liquid detergents by adsorbing them on water-insoluble adsorption sheets, but this has the disadvantage of having to remove the water-insoluble adsorption sheets after washing.

Therefore, the problem to be solved by the present invention is to provide a laundry sheet that can be used in a washing machine that not only completely dissolves during the washing process, but also has excellent cleaning performance, is easy to manufacture, and has guaranteed storage stability.

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

The laundry film according to the present invention (1) is easily dissolved even in low-temperature water and exhibits excellent washing performance, (2) the liquid active ingredients do not come out of the sheet before being put into the washing machine, and (3) it breaks down when used by the consumer. It has an unbreakable tensile strength and is flexible; (4) it is not absorbed by moisture in the air, so it has distribution stability; and (5) it has excellent washing performance.

The present invention relates to gelatin, pectin, dextran, hyaluronic acid, collagen, agar, gum arabic, acacia gum, alginic acid, sodium alginate, methylcellulose, ethylcellulose, hydroxyethylcellulose, sodium carboxymethylcellulose, starch, dextrin, carboxymethyl Among various polymers such as starch, polyvinylpyrrolidone, polyvinyl methacrylate, polyacrylic acid, and polyethylene oxide, it is highly desirable to use polyvinyl alcohol or polyvinyl alcohol-based copolymer as the main material for forming laundry sheets. Based on discovery.

In other words, unlike other film-forming substrates, polyvinyl alcohol or polyvinyl alcohol-based copolymers can maintain physical properties such as tensile strength of the film even if a large amount of active ingredients such as a high content of surfactant are contained in the matrix formed thereby. The present inventor discovered that a relatively large amount of surfactant per unit area can be contained within the physical property limits required for sheet-type detergents, and that excellent washing performance can be achieved even with tissue products of the size of general wet tissues. It has been done.

In the laundry sheet of the present invention, in particular, among polyvinyl alcohol or polyvinyl alcohol-based copolymers with various molecular weights and degrees of saponification, film formulation, solubility, ease of manufacture, storage stability, cleaning performance, process (mixture of When comprehensively considering viscosity, etc., a polymer with a number average molecular weight of 10,000 to 100,000 is preferable, more preferably a polymer with 20,000 to 50,000 is used, and even more preferably a polymer with 20,000 to 30,000 is used.

In addition, the degree of saponification preferred for the purpose of the present invention differs depending on whether the polymer is a copolymer, whether an alkaline builder is used, etc. 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 of formula 1 or 2 below, which is a preferred specific copolymer according to the present invention. When it is a copolymer and an alkali builder is used, the degree of saponification is preferably 60-90%, more preferably 70-85%, and even more preferably 70-82%.

The present invention also relates to a laundry sheet containing a polymer, a surfactant, and an alkali builder, wherein the polymer is a polyvinyl alcohol-based copolymer containing 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 having 8 to 18 carbon atoms (preferably lauryl sulfate alkali metal salt).

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

<Formula 1>

<Formula 2>

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

When PVA is used as the main formulation, there is a problem that it is cured by an alkali builder. However, when a polyvinyl alcohol-based copolymer is used instead of PVA as a film-forming base, the formulation of the film is difficult even if an alkali builder, which is one of the active ingredients for washing, is included. And the washing efficiency of laundry sheets can be improved without deteriorating solubility. However, not all anionic monomers were preferable as monomers for this copolymer, and only copolymers containing anionic monomers having a carboxyl group were preferable for the purpose of the present invention. For example, the PVA copolymer with an anionic monomer having -SO ₃ H gelled due to an alkaline builder, making it difficult for the sheet to be dissolved after manufacturing.

In addition, very specifically, in laundry sheets containing alkyl sulfate metal salts, alkaline builders, and PVA copolymers, unlike PVA, the saponification degree of the PVA copolymer was preferably 60-90%, and more preferably 70-85%. It was preferable, and 70-82% was even more preferable. Specifically, if the degree of saponification is too high, for example, exceeding 90%, the solubility of the sheet is significantly reduced after manufacturing the sheet, and if the degree of saponification is too low, for example, if it is less than 60%, the water solubility of the copolymer is reduced. It has been degraded.

In the present invention, when polyvinyl alcohol or polyvinyl alcohol-based copolymer is used as the main material of laundry sheets, the structure of the surfactant is very unique among a wide variety of surfactants such as nonionic surfactants, anionic surfactants, and amphoteric surfactants. It is based on the unpredictable and surprising discovery that the use of a non-aromatic surfactant without an ethylene oxide group as the main surfactant is highly desirable for the purposes of the present invention, such as film formulation, cleaning performance, and stability. In particular, among the non-aromatic surfactants without an ethylene oxide group in the structure of these surfactants, alkyl sulfate alkali metal salts with 8 to 18 carbon atoms are more preferable, lauryl sulfate alkali metal salts are even more preferable, and sodium lauryl sulfate is most preferable. do.

Preferably, the main surfactant is contained at least 50% by weight, more preferably at least 60% by weight, and even more preferably at least 70% by weight based on the total weight of the surfactant.

When a material containing a large amount of ethylene oxide groups in the surfactant structure, such as SLES (sodium lauryl ether sulfate) or an EO-added nonionic surfactant, is used as the main surfactant, the film forming ability is greatly reduced. This is thought to be the cause of the lower solubility of polyvinyl alcohol in water due to the characteristic of attracting water molecules of the ethylene oxide structure itself and the lowering of the physical properties of laundry sheets. However, the present invention is not limited to this theoretical speculation. no.

In addition, in the case of surfactants with aromatic groups, such as LAS (linear alkylbenze sulphonate), when manufactured into sheets 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.

Therefore, more preferably, the present invention relates to a laundry sheet containing a polyvinyl alcohol polymer/copolymer and a surfactant, wherein the surfactant does not have an ethylene oxide group in the structure and preferably includes a non-aromatic surfactant. , This is the main surfactant, which means that the non-aromatic surfactant without an ethylene oxide group is contained at least 50% by weight (more preferably 60% by weight, even more preferably 70% by weight) relative to the total surfactant content. It is more desirable.

Non-aromatic surfactants without an ethylene oxide group used as the main surfactant include RSO ₄ ^- alkyl sulfate salt of M ⁺ (M is an alkali metal, preferably sodium or potassium, most preferably sodium), α- Olefin sulfonates, alkanesulfonate alkali metal salts (preferably sodium salts), fatty acid methyl ester sulfonate alkali metal salts (preferably sodium salts), fatty acids, alkyl glycosides, etc. can be used, and alkyl sulfate salts are particularly useful in the present invention. It is preferable for various purposes, and surprisingly, sodium lauryl sulfate is even more preferable for various purposes such as film formulation of the present invention. The alkyl or alkane contained in the non-aromatic surfactant structure without an ethylene oxide group preferably has a carbon number of C8 to C18, and the fatty acid preferably has a carbon number of C8 to C18.

Without being limited by theory, in the case of an alkyl sulfate surfactant containing a saturated hydrocarbon of C8-C22 to C8-C18, more preferably C12-C16, polyvinyl alcohol polymer/copolymer as a film forming substrate. Due to its excellent compatibility with , it is assumed to be particularly desirable because it can form a sheet formulation with good strength and increase washing performance even if it contains a high content of surfactant, 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 without an ethylene oxide group is used as the main surfactant, accounting for more than 50% by weight of the surfactant, more preferably more than 60% by weight). In the case of laundry sheets, the total content of surfactant (after drying) is 30 to 80% by weight (more preferably 40 to 70% by weight) relative to the total weight of the sheet, and the content of polyvinyl alcohol polymer/copolymer is 30 to 80% by weight based on the total weight 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).

As shown in the experimental results described later, when the polyvinyl alcohol polymer/copolymer content is less than 35% by weight, the physical properties of the sheet, i.e., strength, are good, but there is a risk of surfactant components being smeared depending on storage conditions. In this case, in addition to the above problems, the strength of the sheet may decrease significantly, causing problems in use.

In addition to the polyvinyl alcohol polymer/copolymer and surfactant, these laundry sheets may contain other additives such as fluorescent dyes and enzymes, which are described in detail below. If the surfactant content is lower than the above range, washing performance deteriorates, and if the content is higher than the above range, the content of polyvinyl alcohol or polyvinyl alcohol-based copolymer is inevitably reduced, making it difficult to manufacture a sheet formulation.

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

(a) The main surfactant is a non-aromatic surfactant without an ethylene oxide group in the structure (more preferably an alkyl sulfate salt with 8 to 18 carbon atoms having the formula RSO ₄ ^- M ⁺ (M is an alkali metal, preferably an alkali metal). is sodium or potassium, most preferably sodium), even more preferably sodium alkyl sulfate, most preferably sodium lauryl sulfate) and

(b) It provides a laundry sheet comprising heptaoxyethylated lauryl alcohol (LA7), nonaoxyethylated lauryl alcohol (LA9), or a mixture thereof as an auxiliary surfactant.

The present invention also provides a laundry sheet manufactured using polyvinyl alcohol or a polyvinyl alcohol-based copolymer and a surfactant as an effective laundry ingredient, and the main surfactant is a non-aromatic surfactant (more preferably one) that does not have an ethylene oxide group in the structure. Preferably, an alkyl sulfate salt with 8 to 18 carbon atoms, more preferably sodium alkyl sulfate, and most preferably sodium lauryl sulfate) is used, and nonionic surfactant LA7 or LA9 (preferably LA7) is used as an auxiliary surfactant. It is based on the surprising discovery that cleaning performance can be significantly improved while maintaining film formulation. When other surfactants with excellent cleaning performance were mixed into the polyvinyl alcohol polymer/copolymer and lauryl sulfate salt system, surprisingly, only LA7 or LA9 did not significantly reduce film formulation or showed significant improvement in cleaning performance.

Therefore, the present invention also preferably uses only lauryl sulfate salt (most preferably sodium salt) and LA7/LA9 (preferably LA7), which are the main surfactants, as surfactants in the laundry sheet of the present invention. A laundry sheet manufactured using the present invention is provided.

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, and more preferably, (a) A laundry sheet is provided, wherein the mixing ratio (a:b) of and (b) is 80:20 to 70:30.

If too much LA7 or LA9, which is an auxiliary surfactant, is mixed, there is a risk that it may bleed into the sheet, worsening the properties of the sheet and making it difficult to handle, and if too little is mixed, the improvement in cleaning performance is not significant.

As a result, the present invention relates to the polyvinyl alcohol or polyvinyl alcohol-based copolymer; The main surfactant RSO ₄ ^- alkyl sulfate salt, which is an alkyl with 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 laundry sheets manufactured using LA7, LA9, or a mixture thereof, which are auxiliary surfactants, 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, A laundry sheet is provided, wherein the content of 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 formulations such as the present invention, it is desirable to use virtually no starch as a formulation agent (film-forming base). As starch was used as a formulation agent, that is, as starch was included as a component of the sheet, the phenomenon of surfactant floating after drying occurred (poor compatibility), and as the starch content increased, the strength of the sheet also decreased. Additionally, as starch content increased, solubility also decreased.

In the present invention, not using it substantially means not including it at all, preferably 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less, and even more preferably not at all.

The laundry sheet according to the present invention contains a fluorescent whitening agent to improve washing performance or film forming ability within a range that does not impair the sheet's film formulation, storage stability, ease of manufacture, etc.; Enzymes (e.g., cellulases, proteases, etc.); Alkali builders (e.g., sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium metasilicate, sodium alkali silicate, sodium neutral silicate, sodium tripolyphosphate, sodium pyrophosphate, sodium borate, zeolite (sodium aluminosilicate), sodium sesquicarbonate , MEA, TEA); Disintegrants/disintegration aids (e.g. starch, cellulose derivatives, sodium chloride, citric acid, glycerin, propylene glycol); Fabric softeners (e.g., quaternary ammonium salt-based cationic surfactants, silicone-type fabric softening ingredients); bleaching agents (e.g., perborates, percarbonates, superphosphates, diacyls, tetraacylperoxides); Dispersants/emulsifiers (e.g., polyoxy alkylene alkyl phenyl ethers, polyoxy alkylene alkyl ethers, polyoxy ethylene polyoxy propylene block polymers); Disinfectants/disinfectants (e.g., sodium hypochlorite, hydrogen peroxide, urea peroxide); Spices; antiseptic; pigment; It may additionally contain antibacterial agents , etc.

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 active ingredient is insufficiently supported, the strength of the film is weak, and it is difficult to obtain the desired performance, and if the thickness of the dried laundry sheet exceeds 1 cm, dissolution is slowed, reducing the cleaning performance. There is a risk that this will deteriorate.

More preferably, the present invention provides 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, and optionally fluorescent agent, based on the total weight of the sheet after drying. Provided is a sheet-like water-soluble laundry detergent comprising 1 to 5% by weight of whitening agent, and optionally 1 to 5% by weight of enzyme. The sheet-type laundry detergent of the present invention is completely dissolved when used in a laundry bin with clothes, so there is no need for a removal process.

The laundry sheet according to the present invention also contains the above-mentioned polyvinyl alcohol or polyvinyl alcohol-based copolymer; The main surfactant described above; In addition to the above-mentioned auxiliary surfactants, other auxiliary surfactants may be further included within a small amount that does not impair the purpose of the present invention. This 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 this structure.

The laundry sheet according to the present invention also contains the above-mentioned polyvinyl alcohol or polyvinyl alcohol-based copolymer; In addition to the main surfactant, an aromatic surfactant may be further included as an auxiliary surfactant within the range that does not impair the purpose of the present invention. As such an aromatic surfactant, an alkylbenzenesulfonate may be used, and the alkylbenzenesulfonate may be used as an aromatic surfactant. The alkyl is preferably a linear alkyl having 8 to 18 carbon atoms.

The laundry sheet of the present invention can be used in a state where two or more layers are integrated by stacking sheets of other layers in addition to the first layer of the sheet according to the present invention.

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

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

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

The present invention relates to a laundry sheet manufactured 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, and has a carbon number of 8 to 18. The alkyl sulfate alkali metal salt of 8-18 provides laundry sheets containing more than 60% by weight of the total surfactant content as the main surfactant.

A laundry sheet is provided in which 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.

A laundry sheet is provided where the polyvinyl alcohol or polyvinyl alcohol-based copolymer has a number average molecular weight of 20,000-50,000.

A laundry sheet is provided where the polyvinyl alcohol or polyvinyl alcohol-based copolymer has a number average molecular weight of 20,000-30,000.

The polymer is polyvinyl alcohol, and the saponification degree of polyvinyl alcohol is 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 alkyl sulfate alkali metal salt with 8 to 18 carbon atoms, which is the main surfactant, is 30 to 60% by weight. %, and the total content of auxiliary surfactant is 10 to 20% by weight.

The laundry sheet includes bubbles and has improved water solubility.

A laundry sheet having a specific gravity of 0.6 to 0.9 is provided.

The present invention relates to a laundry sheet containing a polymer, a surfactant, and an alkali builder, wherein the polymer is a polyvinyl alcohol-based copolymer containing a monomer unit having a carboxyl group, and the surfactant is an alkyl sulfate alkali having 8 to 18 carbon atoms. It provides a laundry sheet containing a metal salt and an alkyl sulfate alkali metal salt having 8 to 18 carbon atoms, which is the main surfactant contained in an amount of 60% by weight or more based on the total surfactant content.

The copolymer includes a vinyl alcohol unit and an anionic monomer unit of the following 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 independently H or methyl, and n is independently an integer of 0-3.

A laundry sheet is provided in which 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 the polyvinyl alcohol-based copolymer is 30 to 50% by weight based on the total weight of the sheet.

A laundry sheet having a number average molecular weight of 20,000-50,000 of the polyvinyl alcohol-based copolymer is provided.

A laundry sheet having a saponification degree of 60-85% of the polyvinyl alcohol copolymer is provided.

The laundry sheet includes bubbles and has improved water solubility.

A laundry sheet having a specific gravity of 0.6 to 0.9 is provided.

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

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

(S2) bubbling step; and

(S3) Provides a method of manufacturing a laundry sheet including the step of drying.

The present invention provides a laundry sheet that is not only completely soluble in water and does not need to be removed after washing, but also has excellent cleaning performance, is easy to use, ensures storage stability, and causes no inconvenience during use.

Figure 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 , the third number refers to the water content (% by weight) compared to solids. 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 .
Figure 2 is a result showing the change in tensile strength caused by replacing part of the PVA used as a formulation with starch. The Y-axis value of the graph means tensile strength and the unit is kgf/cm ² . The red line in FIG. 2 is a boundary line showing 5 kgf/cm ² , which is the minimum tensile strength required in terms of sheet usability (if it is lower than this, it is easily torn or broken).
Figure 3 is a graph showing the change in viscosity as the molecular weight of PVA increases under specific content conditions. At this time, the standard water content of each mixture is 240% of the solid content.

Hereinafter, to aid understanding of the present invention, it will be described in detail through examples. However, the embodiments according to the present invention may 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 present invention are provided to more completely explain the present invention to those skilled in the art.

<Example 1> Selection of polymer suitable for laundry sheets

While manufacturing laundry sheets using various polymers according to Table 1 below, the film formulation, solubility, and storage stability of the polymers were evaluated. 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 obtain a polymer solution or suspension. The polymer solution or suspension was placed on the release film, prepared to a certain thickness using a film applicator from Elcometer, and then dried in a drying oven at 115°C for 10 minutes to prepare a laundry sheet (thickness: 0.01 cm). Film formulation was evaluated in three levels: excellent, average, and poor using the sheets formed during the sheet creation process and after manufacturing.

Solubility was evaluated as follows. The prepared film sheet was cut into 5 cm The time taken for the film to completely disintegrate and dissolve was measured and evaluated in three levels: excellent (within 3 minutes), average (3 to 5 minutes), and poor (more than 10 minutes).

Film formulation solubility Other evaluations polyvinyl alcohol Great Great Good water solubility polyacrylic acid commonly Great High pH, highly soluble in water in a neutralized state, but the formed film is brittle. polyethylene glycol error commonly - polyacrylamide error Great - polyvinylpyrrolidone Great Great Good solubility in ethanol and organic solvents poly ATC Great Great Very hygroscopic Poly DMAEMA Great commonly Solubility is ensured at low pH poly HEA Great commonly - Cellulose (HEC) commonly commonly - Cellulose (HPMC) commonly commonly -

In Table 1, ATC stands for [2-(Acryloyloxy)ethyl]trimethylammonium chloride, DMAEMA stands for Dimethyl aminoehtyl methacrylate, HEA stands for hydroxy ethyl acrylate, HEC stands for hydroxyethylcellulose, and HPMC stands for hydroxypropylmethylcellulose. it means.

As shown in Table 1, polyvinyl alcohol was the most preferred polymer for manufacturing laundry sheets in terms of film formulation, solubility of the manufactured sheets, ease of manufacture, and storage stability. .

<Example 2> Evaluation of the influence of PVA content and molecular weight

In addition, as a result of evaluating film formulation, solubility, ease of manufacture, storage stability, washing performance, and process (viscosity of the compound solution) using polyvinyl alcohol with various molecular weights and degrees of saponification, the number average molecular weight was found to be 10,000 to 100,000. Polyvinyl alcohol or polyvinyl alcohol copolymer is preferred, 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, a polymer having a molecular weight of 20,000 to 50,000 is used for the purpose of the present invention. 30,000 PVA or its copolymer is preferred. Also, regarding the degree of saponification, when the alkali builder is not mixed, it is desirable for the polymer to have a degree of saponification of 80-90%, and when a PVA copolymer is used and the alkali builder is mixed, the degree of saponification is 60-90% (more It was particularly desirable to use a polymer with a content of 70-85%, more preferably 70-82%. When the saponification degree was lower than the above-mentioned degree of saponification, a problem occurred in which water solubility was lowered, and when a polymer having a degree of saponification higher than the above-mentioned degree of saponification was used, a gelling phenomenon was a problem.

Specific experimental results showing the above are shown in Tables 3 and 4 below. Fabrication and evaluation of the sheet were performed similarly to Example 1. At this time, the casting conditions were 1100 ㎛ (mixture coating thickness), and the drying conditions were 115°C for 15 minutes. Film properties (“surface after drying”), including staining scale, were evaluated by scoring. For example, a score of 1 means that there is no problem with the film but it stains the surface, and a score of 3 means that a phase separation phenomenon occurs on the surface of the film and it stains the surface. The evaluation criteria for solubility and tensile strength were as shown in Table 2 below.

Evaluation results very excellent Great commonly error solubility ◎
(within 3 minutes) ○
(within 5 minutes) △
(within 10 minutes) ×
(10 minutes or more) tensile strength
(kgf/ ^cm2 ) ◎
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.) is adjusted to 100% by supplementing or reducing the surfactant (SLS, LA7), and other ingredients (fluorescent whitening agent, enzymes, fragrance, etc.) are adjusted to 100%. The content was fixed at 5% by weight. The basic prescription used was 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). In the table below, the PVA content refers to the weight percent of PVA out of the total solids excluding water, and the water content refers to the weight percent of water compared to the total weight of solids when preparing the blended solution. In other words, in Formulation 1, 40% PVA content means 40% by weight of PVA in the total solid content, and 63% water content means that the solid content is 37% and water is 63% in the mixture for manufacturing the sheet. Therefore, when the solid content is set to 100, it means that the water content is about 170.

* For prescription 13, drying time was added by 2 minutes.

As shown in Tables 3 and 4, when the PVA number average molecular weight is about 15,000 or less, the sheet strength was poor and the surface surfactant floated after drying (poor compatibility). To solve this problem, sheet formulation and strength could be secured by increasing the PVA content in the sheet, but the lowering of the active ingredient content resulted in lower washing performance.

Meanwhile, as the molecular weight increased, the sheet surface became more stable (improved compatibility) and the sheet strength increased. Therefore, the higher the molecular weight, the more advantageous it is to secure sheet formulation at a low PVA content, but the viscosity of the blended solution is so high that it is difficult to secure processability suitable for mass production. On the other hand, in order to improve this, that is, to lower the viscosity, it can be produced with an increased water content, but this causes the problem of a significant decrease in productivity.

Therefore, in terms of sheet strength and compatibility with effective laundry ingredients, it is preferable that the number average molecular weight of PVA or its copolymer used is 20,000 or more. In addition, in terms of the manufacturing process, 5,000 cps or less is appropriate at a certain PVA content (about 30%) and water content (240% by weight relative to solid content), so the number average molecular weight of PVA or its copolymer is preferably 50,000 or less, and 30,000 It was more preferable to have the following.

In this regard, when a sheet is manufactured using 30% by weight of PVA, 52% by weight of SLS, 13% by weight of LA7, and 5% by weight of other ingredients, and using 240 parts by weight of water based on 100 weight of sheet solids, the molecular weight of PVA increases. The viscosity of the polymer solution was measured as it changed, and the results are shown in Figure 3. In the case of polymer solutions used during the manufacturing process, it is undesirable if the viscosity is too high or too low. However, in the case of polymer solutions containing the same types of components as those of the present invention, the viscosity was found to increase rapidly starting from a molecular weight of about 50,000.

For reference, the results of measuring changes in sheet tensile strength according to molecular weight, PVA content, and water content compared to solid content are shown in Figure 1. In terms of sheet usability, a minimum of 5 kgf/cm ² or more is required (if it is less than that, it is easily torn or broken), and if it is 10 kgf/cm ² or more, it is judged to be a good level. In terms of tensile strength, for example, 05-40-170 Prescriptions such as 10-40-170 prescription, 15-30-200 prescription, 10-40-200 prescription, 15-40-240 prescription, 10-30-200 prescription, and 10-35-200 prescription were preferable.

<Example 3> Evaluation of selection of main surfactant

Washing sheets were manufactured according to the ingredients and contents listed in Table 5 below, and the film formulation and cleaning performance of the manufactured sheets were compared and evaluated.

number ingredient Content (unit %) One Polyvinyl Alcohol (PVA) 40% 2 Surfactants in Table 3 below 55% 3 fluorescent brightener 2 % 4 enzyme 1.5% 5 incense and other 1.5%

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

The evaluation results of film formulation and cleaning performance according to the type of surfactant are shown in Table 6 below. Film formulation was evaluated in three levels: excellent, average, and poor, in the same manner as in Example 1. Cleaning performance was evaluated by the method presented below, and if the cleaning power was more than 60% based on the Japanese polluted cloth, it was judged to be excellent, if it was 50-59%, it was judged to be average, and if it was less than 50%, it was judged to be poor.

Specifically, the cleaning power was evaluated using a washing machine under the same conditions, and ordinary tap water was used as the washing water. In addition, cold water was used at the same temperature as that used in general homes when washing, and the soiled cloth used to evaluate the cleaning power was EMPA 116, an artificial wet soiled cloth and protein soiled cloth manufactured by the Japan Laundry Science Association. Additionally, the contaminated fabric was evaluated by attaching it to an actual cotton T-shirt. In addition, 16 contaminated cloths measuring 5 cm x 5 cm were used for comparative evaluation using statistical methods. At this time, the W _B value, which is a value indicating the whiteness of the contaminated cloth, 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 sheets of detergent were used. At the beginning of washing, the laundry sheets prepared in the examples were put in together with the contaminated cloth. The washing conditions were performed at medium water level in the washing machine's standard course (20 minutes of washing, 2 rinses), and the dehydrated contaminated cloth was placed in a constant temperature and humidity room ( It was dried at 25°C, 20%RH) for 1 day, ironed, and the WB value was measured using the same colorimeter. The cleaning power was calculated by substituting the obtained results into the Kubelka-Munch equation represented by Equation 2 below, and the results are shown in Table 6 below.

In Equation 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 cotton cloth.

type designation Film formulation cleaning performance note nonionic surfactant LA5(pentaoxyethylated lauryl alcohol)
(Polyoxyethylene Lauryl Ether) error commonly liquid LA7(heptaoxyethylated lauryl alcohol) error Great liquid LA9(nonaoxyethylated lauryl alcohol) error Great liquid LC7(Laureth-7-citrate) error commonly liquid CA7 (Polyoxyethylene cetyl ether) error commonly semi-solid CA9 error commonly semi-solid CA15 commonly commonly semi-solid SA14 (Polyoxyethylene stearyl ether) commonly commonly semi-solid OA14 (Polyoxyethylene oleyl ether) commonly commonly semi-solid AG200 (Alkyl glucoside) commonly commonly 50% solution C-MEA (Coconut Acid Monoethanol Amide) commonly 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 commonly 25% solution ALS (Ammonium Lauryl Sulfate) error commonly 26% solution AOS (Alpha Olefin sulfonate) error Great 35% solution ALES 3mol (Ammonium Laureth Sulfate) error Great 30% solution LAS(linear alkylbenze sulphonate)-MEA(mono ethanol amine) error commonly semi-solid LAS-Na (Soduim linear alkylbenze sulphonate) error commonly semi-solid Lauric acid-K (Potassium Laurate) error error elegance Myristic acid-K (Potassium Myristrate) error commonly elegance MES (methyl ester sulfonate) error commonly elegance Amphoteric surfactant Amine-oxide error error 30% solution Cocamidopropyl Betaine commonly error elegance

As shown in Table 6 above, surprisingly, when polyvinyl alcohol was used as the polymer base, only sodium lauryl sulfate (SLS) had excellent film formulation, and various other cleaning surfactants had average or poor film formulation. did. For example, surfactants such as LAS, SLES, and MEA had poor compatibility with PVA due to phase separation during the manufacturing process, and the storage stability and ease of handling of the manufactured sheets were poor, as the manufactured sheets were sticky or broken. .

<Example 4> Evaluation of selection of auxiliary surfactant

*Sodium lauryl sulfate was used as the main surfactant, and various nonionic surfactants were used as auxiliary surfactants to prepare and evaluate various laundry sheets according to the prescriptions in Table 7 below. Laundry sheets were manufactured in a similar manner to 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 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 ion
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⁾ refers to polyvinyl alcohol with a degree of saponification of 86.5% and an average degree of polymerization of 500, SLS ⁽²⁾ is sodium lauyl sulfate, and the fluorescent dye ⁽³⁾ is Tinopal CBS-X (Ciba Specialty). Chemical) was used.

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

The 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 manufacturing the samples to a constant thickness of 0.2 mm each, they were cut into ² did. The point at which the film is cut without being able to overcome the force was determined by tensile strength, and considering convenience of use, the values in Table 8 below were used as the standard.

Evaluation results very excellent Great commonly error solubility ◎
(within 3 minutes) ○
(within 5 minutes) △
(within 10 minutes) ×
(10 minutes or more) tensile strength
(kgf/ ^cm2 ) ◎
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 (%)
(Japanese Laundry Science Association contamination report) 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 ◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ○ ○ tensile strength ○ ◎ ◎ ○ ◎ ◎ ◎ ◎ ○ ○ ◎

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

<Example 5> Evaluation of the effect of the content of SLS, the main surfactant, and LA7, the auxiliary surfactant

As shown in the ingredients and contents in Table 10 below, laundry sheets were prepared by changing the contents of SLS, the main surfactant, and LA7, the auxiliary surfactant. The manufacturing method was the same as Example 4.

Ingredients/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% 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 formulation, washing performance, etc. of the laundry sheets prepared in this way were evaluated in the same manner as in Example 4 and are shown in Table 11 below.

Sample Film formulation Cleaning performance (%) Japanese pollutant 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 commonly 72 66 Example 5-6 error 68 60

As shown in Table 11, considering film formulation and cleaning performance, the content of SLS was preferably 40 to 50% by weight relative to the total weight of the sheet, and LA7, a nonionic surfactant, was preferably 5 to 15% by weight.

<Example 6> Comprehensive evaluation

A water-soluble sheet was prepared using the formulation and content shown in Table 12 below, and various aspects were evaluated. The manufacturing method was the same as 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 non-ion
Surfactants LA7 0 5 10 15 20 25 15 15 15 15 - - 55 - - negative ion
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 with a degree of saponification of 86.5% and an average degree of polymerization of 500 was used, LA7, a polyoxyethylene alkyl ether, was used as a nonionic surfactant, AOS stands for α-olefin sulfonate, and fluorescent dye. Tinopal CBS-X (Ciba Specialty Chemicals) was used.

Sheet Formulation evaluation

The formulation of the water-soluble sheet detergent prepared in the comparative examples and examples was 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 with no smearing phenomenon.

○: The sheet formulation is flexible, but some liquid ingredients remain.

△: The sheet lacks flexibility, and some staining occurs.

×: Sheet formulation does not work, and a lot of liquid ingredients remain.

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

As shown in Table 13, the sheet formulation of Examples a, b, c, d, k, and l was excellent, and it was confirmed that as the nonionic surfactant and SLES contents increased, the film formulation decreased significantly.

Solubility and tensile strength evaluation

The laundry sheets prepared in the above Examples and Comparative Examples were tested in the same manner as Example 4 to evaluate solubility and tensile strength. 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 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ ◎ - ○ - tensile strength ◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ △ ◎ ◎ - △ -

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

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

Cleansing power evaluation

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

Specifically, the cleaning power was evaluated using a washing machine under the same conditions, and ordinary tap water was used as the washing water. In addition, cold water was used at the same temperature as that used in general homes when washing, and the soiled cloth used to evaluate the cleaning power was EMPA 116, an artificial wet soiled cloth and protein soiled cloth manufactured by the Japan Laundry Science Association. Additionally, the contaminated fabric was evaluated by attaching it to an actual cotton T-shirt. In addition, 16 contaminated cloths measuring 5 cm x 5 cm were used for comparative evaluation using statistical methods. At this time, the WB value, which is a value indicating the whiteness of the contaminated cloth, 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 sheets of detergent were used. At the beginning of the wash, laundry sheets and detergent were each added together with the soiled cloth. Washing conditions were performed at medium water level on the washing machine's standard course (20 minutes of washing, 2 rinses), and the dehydrated soiled cloth was placed in a constant temperature and humidity room (25°C). , 20%RH) for 1 day, ironed, and measured the W _B value using the same colorimeter. The obtained results were 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 contamination report) 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 Table 15, among Examples a, b, c, d, k and l, which have appropriate sheet formulation, solubility and tensile strength, 15% by weight of polyoxyethylene alkyl ether, a nonionic surfactant, is contained. Example d had the best cleaning performance.

<Example 7> Stability (hygroscopicity) evaluation

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

1 month later 2 months later note dry residue film condition dry residue film condition room temperature 96% Good 96.5% Good As the moisture in the sheet dries, the sheet becomes 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 initial state. 30 degrees, 80% humidity 94.5% Good 94% Good It feels a little damp, but it doesn't stick to your hands, it's not sticky, and the film has become slightly 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 above, despite being a water-soluble sheet detergent, the product was able to secure stability under various conditions, including high temperature and humidity during the rainy season.

<Example 8> Evaluation of PVA copolymer use

Laundry sheets were manufactured according to the prescription in Table 17 below, and the manufacturing method was the same as Example 4.

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 non-ion
Surfactants LA7 15 13.5 15 14.3 13.6 13.0 12.3 11.6 10.9 negative ion
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 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⁾ refers to polyvinyl alcohol with a degree of saponification of 86.5% and an average degree of polymerization of 500, and PVA copolymer ⁽²⁾ refers to vinyl alcohol (98 mol%, degree of saponification: about 77 mol%) - methacrylic acid ( 2mol%) copolymer with an average degree of polymerization of 500 was used, SLS ⁽³⁾ was sodium lauyl sulfate, sodium carbonate (soda) was used as builder ⁽⁴⁾ , and Tinopal CBS-X was used as fluorescent dye ⁽⁵⁾ . (Ciba Specialty Chemicals) was used.

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 (%)
(Japanese Laundry Science Association contamination report) 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 ◎ ◎ ◎ ◎ ◎ ◎ ◎ tensile strength ◎ △ ◎ ◎ ◎ ○ ○ △ △

As shown in Table 18 above, when a builder is added to PVA, the PVA hardens and the solubility and physical properties are significantly reduced, and the cleaning performance also does not show the builder effect due to the insoluble components. However, when using PVA-copolymer, curing does not occur even when a builder is added, so the cleaning power is improved by the builder. However, above a certain concentration, the effect is offset by a decrease in cleaning power due to a decrease in the relative amount of surfactant. Additionally, when the amount of builder was 7.5% or more, the sheet strength was reduced due to the large amount of builder in the film.

<Example 9> Evaluation of the effect of adding starch

Sheets with the formulation shown in Table 19 below were manufactured, and the effect of adding starch was evaluated while using PVA, starch, or a mixture thereof as a formulation agent. The results were evaluated in the same manner as the experiment in Example 2 and are summarized in Table 20 below, and the tensile strength among the results in Table 20 is shown in Figure 2.

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

Formulation agent
PVA/starch
(total 40%) Casting after drying
surface Solubility tensile strength
(kgf/ ^cm2 ) note A 1/0 Good Good ◎ 10.7 (○) B 3/1 Good Floating phenomenon (3 points) X (Hazy) 6 (△) Starch powder settles 3/1 (full powder 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 (full powder gelatinization) 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 (full powder gelatinization) Good Floating phenomenon (4 points) Δ 2.1 (X) Some residue left

As shown in Table 20 and Figure 2, as starch was mixed and used as a formulation agent, that is, starch was included as a sheet component, the phenomenon of surfactant floating after drying occurred (poor compatibility), and the starch content increased. As the thickness increased, the strength of the sheet also decreased. Additionally, as starch content increased, solubility also decreased. Therefore, it was found that it is preferable not to use starch while manufacturing laundry sheets like the present invention. In order to overcome the above compatibility and tensile strength problems, there is a problem that the content of the formulation agent in the sheet must be increased (more than 50%), and there is also a disadvantage that the starch must first be gelatinized to improve solubility.

Claims (2)

In the laundry sheet manufactured using polyvinyl alcohol or polyvinyl alcohol-based copolymer as the polymer and containing a surfactant,
The sheet is formed by drying a laundry sheet manufacturing solution containing water,
The surfactant is contained in a polymer matrix formed by mixing a polymer and a surfactant together,
The surfactant includes an alkyl sulfate alkali metal salt having 8 to 18 carbon atoms,
It further contains an auxiliary surfactant,
The laundry sheet is characterized in that it does not contain starch or contains starch in an amount of 5% by weight or less based on the dry weight of the sheet. 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.