LAUNDRY SHEET

Abstract

The present invention provides a laundry sheet in which at least one laundry component is distributed inside a matrix formed from a water-soluble polymer, which is a polyvinyl alcohol or a polyvinyl alcohol-based polymer, and the laundry sheet has (i) a foamability of 0.5-0.9 (g/cm.sup.3) or (ii) a drape stiffness of 3.5-7.5 cm.

Claims

1. A laundry sheet comprising at least one ingredient for laundry distributed in a water-soluble polymer matrix, wherein the water-soluble polymer is polyvinyl alcohol, and the laundry sheet has (i) a foamability of 0.5-0.9 (g/cm.sup.3) or (ii) a drape stiffness of 3.5-7.5 cm.

2. The laundry sheet according to claim 1, wherein the foamability is 0.6-0.8 (g/cm.sup.3).

3. The laundry sheet according to claim 1, wherein the drape stiffness is 4.7-6.5 cm.

4. A laundry sheet comprising at least one ingredient for laundry distributed in a water-soluble polymer matrix, wherein the water-soluble polymer is polyvinyl alcohol or a polyvinyl alcohol-based copolymer, and the polyvinyl alcohol or polyvinyl alcohol-based copolymer has a glass transition temperature (Tg) of 56-75 C.

5. The laundry sheet according to claim 4, wherein the glass transition temperature is 62-73 C.

6. The laundry sheet according to claim 1, which further comprises at least one ingredient selected from the group consisting of a surfactant, builder and fragrance.

7. The laundry sheet according to claim 6, wherein the total content of polyvinyl alcohol is 30-50 wt % based on the total weight of the sheet after drying.

8. The laundry sheet according to claim 6, wherein the total content of surfactant is 30-60 wt % based on the total weight of the sheet after drying.

9. The laundry sheet according to claim 8, wherein the surfactant is a C8-18 alkyl sulfate alkali metal salt.

Description

BEST MODE

[0061] Examples will be described more fully hereinafter so that the present disclosure can be understood with ease. The following examples may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth therein. Rather, these exemplary embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0062] 1. Foamability, Physical Properties and Cuttability of Water-Soluble Laundry Sheet

[0063] (1) Manufacture of Sheet

TABLE-US-00001 TABLE 1 Ex. 01 02 03 04 05 06 07 08 Foamability 0.35 0.4 0.5 0.6 0.7 0.8 0.9 0.95 (g/cm.sup.3) Solubility Poor Insufficient Satisfactory Satisfactory Excellent Excellent Excellent Excellent Physical X properties Cuttability 1 1 2 2 3 3 3 2

[0064] Each of the sheets having a foamability as shown in Table 1 was fabricated. First, 200 g of PVA (saponification degree: 86.5%, average polymerization degree: 500) was introduced to 800 g of distilled water and dissolved therein at 80 C. for 4 hours to form 20 wt % PVA solution. Next, a surfactant (SLS, sodium lauryl sulfate), builder (sodium carbonate), fragrance, or the like were introduced to the PVA solution (40 wt % of PVA, 48 wt % of surfactant, 10 wt % of builder, 2 wt % of fragrance) and mixed therewith by using a mechanical stirrer so that they might be dissolved. Herein, rpm of the mechanical stirrer and agitation time were controlled to form a PVA solution having each foamability as shown in Table 1. Then, the PVA solution was loaded on a release film, controlled to a predetermined thickness by using a film applicator available from Elcometer Co., and dried in a drying oven at 105 C. for 10 minutes to obtain a PVA film sheet. The foamability was controlled by adjusting the air introduction amount in a foam controlling device and the rotation number of the stirrer.

[0065] (2) Evaluation of Physical Properties

[0066] A. Determination of Solubility

[0067] Solubility was determined as follows. Each sheet was cut into a size of 5 cm5 cm and introduced to a 500 mL beaker. Next, 300 mL of purified water at 15 C. was introduced to the beaker and agitation was carried out at a rate of 300 rpm. The time required for complete disintegration and dissolution of the film was measured and evaluated in a 4-grade scale: excellent (within 3 minutes), satisfactory (3-5 minutes), insufficient (5-10 minutes), and poor (more than 10 minutes).

[0068] B. Calculation of Foamability

[0069] Foamability was expressed by the content of foam contained in the sheet per unit volume.

[0070] Foamability was calculated according to the following formula after measuring the net density, i.e. the content of foam per unit volume of the sheet:

Foamability=1Net density[Formula]

[0071] C. Evaluation of Physical Properties

[0072] Evaluation of physical properties: (excellent), (good), X (poor: easily broken or smashed)

[0073] D. Cuttability

[0074] Cuttability was evaluated by providing each sheet to 10 users and allowing them to evaluate how they easily tear the sheet to a desired size by using hands in a three-grade scale.

[0075] Functional test results: 1 (poor: not easily cut), 2 (insufficient: hardly cut into a desired size), 3 (good: easily cut into a desired size)

[0076] D. Results

[0077] After manufacturing the sheets as described above, in the case of the sheets having a foamability according to Ex. 01 and Ex. 02, they show a low solubility of 5 minutes or more and thus have low commercial value. In the case of the sheets having a foamability according to Ex. 03-Ex. 08, they show excellent solubility. However, when the foamability exceeds 0.9, like Ex. 08, the sheet product is easily broken undesirably.

[0078] When the sheet is fabricated to have a foamability of 0.5-0.9, it is possible to manufacture the sheet with ease and to provide the sheet with excellent solubility.

[0079] 2. Determination of Drape Stiffness

[0080] (1) Manufacture of Sheet

[0081] The laundry sheets according to the following Tables 2 and 3 were manufactured in the same manner as described above.

TABLE-US-00002 TABLE 2 Ex. 09 10 11 12 13 14 15 16 17 18 19 20 Drape 1.10 2.93 3.96 4.54 4.81 5.50 6.06 6.11 7.08 8.13 9.35 9.87 stiffness Physical X X X X X properties Cuttability 2 2 2 2 3 3 3 3 3 2 1 1

TABLE-US-00003 TABLE 3 Ex. 21 22 23 24 25 26 27 28 Foamability 0.35 0.4 0.5 0.6 0.7 0.8 0.9 0.95 (g/cm.sup.3) Drape 8.35 7.92 6.98 6.11 5.38 4.12 3.35 2.37 stiffness Physical X X properties Cuttability 1 2 2 3 3 3 3 2

[0082] (2) Physical Properties

[0083] A. Method for Determination of Drape Stiffness

[0084] Drape stiffness was derived according to the following formula.

C=D/2,G=C.sup.3W

[0085] wherein, C: drape stiffness

[0086] D: length (cm) of specimen sagging on the stand tilted surface

[0087] G: flex stiffness

[0088] W: weight of sample (g/cm.sup.2)

[0089] Drape stiffness was determined according to the Cantilever method (ISO 9073-7, ASTM D-5732) by pushing out a specimen having a size of 2.5 cm15 cm until it is in contact with a 41.5 tilted surface and measuring the length of the specimen.

[0090] B. Evaluation of Physical Properties

[0091] Evaluation of physical properties: (excellent), (good), X (poor: easily broken or smashed)

[0092] C. Cuttability

[0093] Cuttability was evaluated by providing each sheet to 10 users and allowing them to evaluate how they easily tear the sheet to a desired size by using hands in a three-grade scale.

[0094] Functional test results: 1 (poor: not easily cut), 2 (insufficient: hardly cut into a desired size), 3 (good: easily cut into a desired size)

[0095] D. Results

[0096] The sheets of Ex. 11-Ex. 17 were not smashed easily during manufacture. Particularly, the sheets of Ex. 13-Ex. 16 was manufactured with ease and the resultant sheets are not smashed. Meanwhile, referring to Ex. 24 and Ex. 25, it can be seen that when satisfying both the foamability and drape stiffness according to the present disclosure, the sheet has excellent cuttability and physical properties.

[0097] 3. Glass Transition Temperature and Physical Properties of Water-Soluble Polymer

[0098] (1) Manufacture of Sheet

TABLE-US-00004 TABLE 4 Ex. 29 30 31 32 33 34 35 36 37 38 39 40 Tg ( C.) 48 52 56 60 63 65 68 70 75 78 82 85 Physical X X X X X properties

[0099] Each of the sheets having a Tg as shown in Table 4 was manufactured. First, 200 g of each PVA (Ex. 29-Ex. 40) was introduced to 800 g of distilled water and dissolved therein at 80 C. for 4 hours to form 20 wt % PVA solution. Next, a surfactant (SLS, sodium lauryl sulfate), builder (sodium carbonate), fragrance, or the like were introduced to the PVA solution (40 wt % of PVA, 48 wt % of surfactant, 10 wt % of builder, 2 wt % of fragrance) and mixed therewith by using a mechanical stirrer so that they might be dissolved therein. Then, the PVA solution was loaded on a release film, controlled to a predetermined thickness by using a film applicator available from Elcometer Co., and dried in a drying oven at 105 C. for 10 minutes to obtain a PVA film sheet (thickness: 0.01 cm).

[0100] (2) Physical Properties

[0101] A. Determination of Tg

[0102] Tg was determined by using a heat flux DSC (differential scanning calorimeter) available from Mettler-Toledo Co. at a heating rate of 10 C./min.

[0103] B. Evaluation of Physical Properties

[0104] Results: (excellent), (good), X (poor: easily broken or smashed)

[0105] C. Results

[0106] The sheets using PVA having a Tg according to Ex. 29, Ex. 30, Ex. 38, Ex. 39 and Ex. 40 are broken or smashed easily. Thus, it is difficult to formulate those sheets and the sheets show low commercial value. When using PVA having a Tg according to Ex. 31-Ex. 37, it is relatively easy to formulate the sheets and the sheets have good quality.

INDUSTRIAL APPLICABILITY

[0107] The present disclosure provides a laundry sheet which is dissolved completely in water and is not required to be removed after laundry. The laundry sheet according to the present disclosure has excellent washing quality, is convenient to use, and allows the users to cut it easily as necessary for use.