WATER-SOLUBLE FILM AND PACKAGING

Abstract

There is provided a water-soluble film containing polyvinyl alcohol resin, wherein the ratio of fluorine element to the total amount of elements (F1S) found at the time of analyzing a first surface of the water-soluble film through X-ray Photoelectron Spectroscopy is 1 mol % or greater and 25 mol % or less; and ratio of the fluorine element to the total amount of elements (F1B) found at the time of analyzing a surface 0.1 μm deep from the first surface through X-ray Photoelectron Spectroscopy is 0.5 mol % or less. As a result, a water-soluble film having excellent detachability from the support, as well as excellent transparency and sealing property, and a packaging body for chemicals may be provided using this film.

Claims

1. A water-soluble film containing polyvinyl alcohol resin, wherein the ratio of fluorine element to the total amount of elements (F1S) found at the time of analyzing a first surface of the water-soluble film through X-ray Photoelectron Spectroscopy is 1 mol % or greater and 25 mol % or less, and the ratio of the fluorine element to the total amount of elements (F1B) found at the time of analyzing a surface 0.1 μm deep from the first surface through X-ray Photoelectron Spectroscopy is 0.5 mol % or less.

2. The water-soluble film according to claim 1, wherein the ratio of fluorine element to the total amount of elements (F2S) found at the time of analyzing a second surface facing the first surface of the water-soluble film through X-ray Photoelectron Spectroscopy is 1 mol % or greater and 25 mol % or less; and the ratio of fluorine element to the total amount of elements (F2B) found at the time of analyzing a surface 0.1 μm deep from the second surface through X-ray Photoelectron Spectroscopy is 0.5 mol % or less.

3. The water-soluble film according to claim 2, wherein difference between the F1S and the F2S is 2.5 mol % or greater.

4. The water-soluble film according to claim 1, wherein the fluorine element is contained in a fluorine-containing surfactant having a molecular weight of 10,000 or less.

5. The water-soluble film according to claim 4, wherein the fluorine-containing surfactant is at least one type selected from a group consisting of fluoroalkyl alcohol, fluoroalkyl carboxylate, fluoroalkyl sulfate ester, fluoroalkyl sulfonate, fluoroalkyl phosphoric ester salt, fluoroalkyl phosphonate, fluoroalkyl phosphonous salt, and fluoroalkyl ammonium salt.

6. The water-soluble film according to claim 5, wherein the fluorine-containing surfactant is at least one type selected from a group consisting of fluoroalkyl alcohol, fluoroalkyl phosphoric ester salt, and fluoroalkyl sulfonate.

7. A packaging body in which a water-soluble film containing polyvinyl alcohol resin stores a chemical, wherein the ratio of fluorine element to the total amount of elements (F1S) found at the time of analyzing a first surface of the water-soluble film through X-ray Photoelectron Spectroscopy is 1 mol % or greater and 25 mol % or less, and the ratio of the fluorine element to the total amount of elements (FIB) found at the time of analyzing a surface 0.1 μm deep from the first surface through X-ray Photoelectron Spectroscopy is 0.5 mol % or less.

8. The packaging body according to claim 7, wherein the chemical is a pesticide, a detergent, or a disinfectant.

9. The packaging body according to claim 7, wherein the chemical is in a liquid state.

10. A formation method for a water-soluble film containing polyvinyl alcohol resin, comprising the step of coating a support with the fluorine-containing surfactant, and flow-casting a film forming solution containing polyvinyl alcohol resin in film form on the resulting coated surface, wherein the ratio of fluorine element to the total amount of elements (F1S) found at the time of analyzing a first surface of the water-soluble film through X-ray Photoelectron Spectroscopy is 1 mol % or greater and 25 mol % or less, and the ratio of the fluorine element to the total amount of elements (F1B) found at the time of analyzing a surface 0.1 μm deep from the first surface through X-ray Photoelectron Spectroscopy is 0.5 mol % or less, and wherein the fluorine element is contained in a fluorine-containing surfactant having a molecular weight of 10,000 or less.

11. The formation method for the water-soluble film according to claim 10, wherein the support is coated with the fluorine-containing surfactant by continuously coating the support with a solution of the fluorine-containing surfactant or an aqueous dispersion of the same, and drying the resulting coated support.

12. The water-soluble film according to claim 7, wherein the ratio of fluorine element to the total amount of elements (F2S) found at the time of analyzing a second surface facing the first surface of the water-soluble film through X-ray Photoelectron Spectroscopy is 1 mol % or greater and 25 mol % or less; and the ratio of fluorine element to the total amount of elements (F2B) found at the time of analyzing a surface 0.1 μm deep from the second surface through X-ray Photoelectron Spectroscopy is 0.5 mol % or less.

13. The water-soluble film according to claim 12, wherein difference between the F1S and the F2S is 2.5 mol % or greater.

14. The water-soluble film according to claim 7, wherein the fluorine element is contained in a fluorine-containing surfactant having a molecular weight of 10,000 or less.

15. The water-soluble film according to claim 14, wherein the fluorine-containing surfactant is at least one type selected from a group consisting of fluoroalkyl alcohol, fluoroalkyl carboxylate, fluoroalkyl sulfate ester, fluoroalkyl sulfonate, fluoroalkyl phosphoric ester salt, fluoroalkyl phosphonate, fluoroalkyl phosphonous salt, and fluoroalkyl ammonium salt.

16. The water-soluble film according to claim 15, wherein the fluorine-containing surfactant is at least one type selected from a group consisting of fluoroalkyl alcohol, fluoroalkyl phosphoric ester salt, and fluoroalkyl sulfonate.

17. The formation method for the water-soluble film according to claim 10, wherein the fluorine-containing surfactant is at least one type selected from a group consisting of fluoroalkyl alcohol, fluoroalkyl carboxylate, fluoroalkyl sulfate ester, fluoroalkyl sulfonate, fluoroalkyl phosphoric ester salt, fluoroalkyl phosphonate, fluoroalkyl phosphonous salt, and fluoroalkyl ammonium salt.

18. The formation method for the water-soluble film according to claim 17, wherein the fluorine-containing surfactant is at least one type selected from a group consisting of fluoroalkyl alcohol, fluoroalkyl phosphoric ester salt, and fluoroalkyl sulfonate.

Description

WORKING EXAMPLES

[0115] The present invention is described in detail below through working examples; however, the present invention is not limited in anyway by the following working examples. Note that adopted evaluation items and methods thereof in the following working examples and comparative examples are as described below.

[0116] (1) X-ray Photoelectron Spectroscopy (XPS)

(1-1) Analysis of Ratio of the Fluorine Element to the Total Amount of Elements of the Water-Soluble Film Surface

[0117] A film is cut to a size of 5 mm×5 mm and set on a measurement pedestal using conductive double-sided tape. Both surfaces of the film are measured and the value of the surface with larger fluorine element content is used. Each sample is measured under the following measurement conditions.

[0118] Measuring apparatus: Ohi Quantera SXM (ULVAX-PHI. INC.)

[0119] Analysis software: Multi Pack ver9.0 (ULVAX-PHI. INC.)

[0120] X-ray source: Monochromatic Al Kα(1486.6 eV)

[0121] X-ray beam diameter: 100 μmφ, (25 W, 15 kV)

[0122] Measuring range: 100 μm×300 μm

[0123] Signal capture angle: 45°

[0124] Electrostatic charge neutralization conditions: neutralizing electron gun, Ar+ ion gun

[0125] Vacuum degree: 1×10.sup.−6 Pa

[0126] Measuring elements (peak of excited inner shell atoms used for quantification): C (1s), N (1s), O (1s), F (1s), Na (1s), Si (2p), P (2p), S (2p)

[0127] The obtained spectrum is analyzed to find the ratio of the fluorine element to the total amount of elements of the film surface.

[0128] (1-2) Analysis of Ratio of the Fluorine Element to the Total Amount of Elements at 0.1 μm Deep from the Surface

[0129] In an XPS analysis apparatus, once the film is etched until a depth of 0.1 μm using C60, element content at 0.1 μm film depth is quantified so as to calculate the ratio of the fluorine element to the total amount of elements under the same conditions described above.

(Etching Conditions)

[0130] Measurement condition: acceleration voltage 10 kV

[0131] Sample current: 20 mA

[0132] Scanning field: 0.5 mm×2.0 mm

[0133] Etching rate: 1.0 nm/ min

[0134] (2) Evaluation of Detachability from Support

[0135] When forming the water-soluble film, detached state of the film from the support is visually observed and evaluated according to the following criteria. Detachability evaluation criteria:

[0136] A . . . Detach positions are horizontal along the width, and there are no creases nor stretches generated in the film surface.

[0137] B . . . Detach positions are horizontal along the width, but there are creases and stretches generated in the film surface.

[0138] C . . . Detach positions wave along the width, and there are creases and stretches generated in the film surface.

[0139] (3) Evaluation of Sealing Property

[0140] Sealing property between film surfaces having a low ratio of the fluorine element to the total amount of elements is evaluated.

[0141] (3-1) Preparation

[0142] Two oblong test pieces of a water-soluble film, each having dimensions of approximately 30 cm in the flow direction (MD) of film formation and approximately 10 cm along the width (TD), are cut out for each sample, and kept for 16 hours in an environment of 10° C. and 35% RH (Relative Humidity).

[0143] (3-2) Bonding Films Together

[0144] One piece of the pre-prepared films is placed on a stand in the environment of 10° C. and 35% RH, and the four corners of the film are fixed using adhesive tape. One more piece of the film is stacked thereupon, both ends of respective 10 cm sides are fixed using adhesive tape, and the unfixed ends are passed through an ESIPROOF proofing roller using a 140/10 anilox roller. 0.5 mL of deionized water is poured on a doctor blade of the ESIPROOF proofing roller, and the roller is pulled at a speed of approximately 7.5 cm/sec, bonding the two films together. Note that at this time, since the roller is set to the chuck of a tension tester without being pulled to the end of the film, a part not bonded to the end of the film is left. Three short strip test pieces having a width of 25 mm in MD are cut out from the bonded water-soluble film

[0145] (3-3) Measurement of Seal Strength Once the test pieces are bonded and left for ten minutes, they are set in a tension tester, peeled in conformity to a T-peel test based on JIS K6854-3: 1999, and the average value of detaching force of the three obtained test pieces is taken as the adhesive force. Measurement condition for this test is an elastic stress rate of 30 mm/min.

Evaluation Criteria:

[0146] A . . . Excellent sealing property . . . seal strength standard: exceeds 5N/25 mm [0147] B . . . Slightly inferior sealing property . . . seal strength standard: 1 to 5N/25 mm [0148] C . . . Cannot seal . . . seal strength standard: less than 1N/25 mm

[0149] (4) Evaluation of Transparency

[0150] A liquid (pseudo detergent) dyed green is packaged inside of the respective films, and transparency is evaluated by visibility of content.

Evaluation Criteria:

[0151] A . . . Transparency is excellent, and can clearly see through . . . Standard: overall haze value is 50% or less [0152] B . . . There is slight cloudiness, but can clearly see through . . . Standard: overall haze value is 50 to 70% [0153] C . . . Film looks cloudy and is opaque, and cannot see through clearly . . . Standard: overall haze value is 70% or greater

[0154] (5) Evaluation of Film Adhesion

[0155] The water-soluble FVA film is cut out to a size of 3 cm×20 cm, rolled on a short end as a pivot into a cylindrical form having an inner diameter of approximately 1 cm, and then has both end parts cut off. This forms a small water-soluble film roll having an inner diameter of 1 cm and width of 1 cm. A double clip (product name Scel-bo manufactured by Kokuyo Co., Ltd. ‘Scel-bo’ is a registered trademark of Kokuyo Co., Ltd.) having an aperture width of 15 mm is used to clasp near the central axis of the obtained roll such that the direction of the clasping portion of the clip corresponds to the axial direction of the roll, and the roll is then stored for 16 hours under the conditions of 60° C. and 90% RH. The stored film roll is unwound, and the degree of adhesion between contact surfaces at the ends is evaluated.

Evaluation Criteria:

[0156] A . . . There is no adhesion between contact surfaces at the ends, and the water-soluble film has been unwound without resistance. [0157] B . . . There is resistance when unwinding, but the water-soluble film has been unwound due to added force. [0158] C . . . There is adhesion between contact surfaces at the ends, and the water-soluble film has not been unwound.

[0159] <Working Example 1>

[0160] A metal drum (first drying roller), which will be a film forming support, is continuously coated with a 0.1 mass % aqueous dispersion including fluoroalkyl alcohol (fluorotelomer alcohol: may be referred to as FTOHs hereafter) as the fluorine-containing surfactant using a roll coater so that 2.5 g/m.sup.2 aqueous dispersion is accumulated, hot air of 80° C. is blown on it to dry, and the metal drum surface is continuously coated with FTOHs.

[0161] Subsequently, a film forming solution 60 mass % in volatile component rate is prepared, where the film forming solution is constituted by: 100 parts mass methyl maleate (may be referred to as MA hereafter) modified PVA (saponification degree of 99.9 mol %, polymerization degree of 1700, and MA modification degree of 5 mol %) obtained by saponifying polyvinyl acetate; 50 parts mass glycerine as a plasticizer; 2.0 parts mass diethanolamide laurate as a surfactant; and water, and is then filtered so as to obtain a film forming solution. The obtained film forming solution is continuously sprayed in film form on the first drying roller (at surface temperature of 80° C.) that is coated with FTOHs output from a T-die, and hot air of 85° C. is blown onto the entire open surface on the first drying roller at a speed of 5 m per second so as to dry it. Next, it is detached from the first drying roller, and is dried using a second drying roller and subsequent ones at a roller surface temperature of 75° C., with either the open surface or the support surface making physical contact with each of the drying rollers alternately, and is wound by a winding tension of 90 N/m, resulting in generation of a water-soluble film 35 μm in depth and 1200 μm in width.

[0162] As results of taking a sample of the water-soluble film from the obtained film roll and measuring the amount of the fluorine element using XPS, F1S is 16.7 mol %, F1B is a lower detection limit or less (<0.1 mol %), F2S is 9.4 mol %, and F2B is the lower detection limit or less (<0.1 mol %). Evaluation results of detachability from the metal drum, sealing property, visibility of content, and film adhesion are all favorable.

[0163] <Working Example 2>

[0164] Aside from using MA modified PVA having a saponification degree of 88 mol %, a water-soluble film is obtained in the same manner as in Working Example 1.

[0165] <Working Example 3>

[0166] Aside from using 30 parts mass of plasticizer, a water-soluble film is obtained in the same manner as in Working Example 1.

[0167] <Working Example 4>

[0168] Aside from using monomethyl maleate (may be referred to as MMM hereafter) modified PVA having a modification rate of 2 mol % and a saponification degree of 88 mol %, and using 25 parts mass of plasticizer, a water-soluble film is obtained in the same manner as in Working Example 1.

[0169] <Working Examples 5 and 6>

[0170] Aside from using perfluoroalkyl sulfonate salt and tris(2,2,2-trifluoroethyl) phosphate as the fluorine-containing surfactant, respectively, water-soluble films are obtained in the same manner as in Working Example 1.

[0171] <Working Examples 7 and 8>

[0172] Aside from coating the first drying roller with 1.1 g/m.sup.2 and 8.1 g/m.sup.2 aqueous dispersions of the fluorine-containing surfactant, respectively, water-soluble films are obtained in the same manner as in Working Example 4.

[0173] <Working Example 9>

[0174] Aside from continuously coating the second drying roller, with which the open surface is making physical contact, with the aqueous dispersion of FTOHs, as with the first drying roller, a water-soluble film is obtained in the same manner as in Working Example 1.

[0175] <Comparative Example 1>

[0176] Aside from coating with 24.6 g/m.sup.2 aqueous dispersion of the fluorine-containing surfactant, a water-soluble film is obtained in the same manner as in Working Example 1.

[0177] F1S of this film is 38.5 mol % and F1B is 1.2 mol %, and while detachability from the drum is favorable, sealing property is poor.

[0178] <Comparative Example 2>

[0179] Aside from drying using only remaining heat from the first drying roller without hot air drying after being coated with the aqueous dispersion of the fluorine-containing surfactant, a water-soluble film is obtained in the same manner as in Working Example 1. F1S of this film is 5.6 mol %, F1B is 3.2 mol %, and detachability from the drum is poor.

[0180] <Comparative Example 3>

[0181] Instead of coating with the fluorine-containing surfactant every cycle, a fluorine resin coating is applied by coating the roll with an ethanol solution of fluorine-containing resin (dichloropentafluoropropane (HCFC-225)) and then drying it. Otherwise, a water-soluble film is obtained in the same manner as in Working Example 1. Detachability of the film is excellent; however, when unwinding the film roll, films adhere to each other and adhere inside of a carrying roller, thereby generating creases in the film

[0182] <Comparative Examples 4 and 5>

[0183] Instead of coating with the fluorine-containing surfactant, FTOHs is added to the PVA film forming solution so as to reach 5000 ppm and 100 ppm, thereby forming films Otherwise, water-soluble films are obtained in the same manner as in Working Example 1. While detachability of these films is favorable in Comparative Example 4, it is poor in Comparative Example 5. Both of these films have poor transparency, resulting in cloudy films.

[0184] The evaluation results of the obtained films are given in Table 1.

TABLE-US-00001 TABLE 1 Working Examples Comparative Examples 1 2 3 4 5 6 7 8 9 1 2 3 4 5 Modified Type MA MA MA MMM MA MA MMM MMM MA MA MA MA MA MA Degree of 5 5 5 2 5 5 2 2 5 5 5 5 5 5 modification [mol %] Saponification degree [mol %] 99.9 85 99.9 88 99.9 99.9 88 88 99.9 99.9 99.9 99.9 99.9 99.9 Plasticizer [mass %/PVA] 50 50 30 25 50 50 25 25 50 50 50 50 50 50 Fluorine- Type* A A A A B C A A A A A D A A containing First drying roll 2.5 2.5 2.5 2.5 2.5 2.5 1.1 8.1 2.5 24.6 2.5 0 0 0 surfactant coated amount [g/m.sup.2] Contained amount in 0 0 0 0 0 0 0 0 0 0 0 0 5000 100 film [ppm/PVA] First drying roller hot Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes air drying Coating second — — — — — — — — Yes — — — — — drying roller Ratio of F1S 16.7 15.5 17.5 13.6 20.2 19.4 5.6 23.5 21.3 38.5 5.6 0.2 23.5 0.8 fluorine to F1B <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.3 <0.1 1.2 3.2 <0.1 20.8 0.3 total F2S 9.4 7.9 10.1 0.8 8.1 6.9 1.8 13.9 19.2 22.1 1.1 <0.1 22.7 0.7 amount of F2B <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.2 <0.1 <0.1 <0.1 <0.1 18.2 0.5 elements | F1S − F2S | 7.3 7.6 7.4 12.8 12.1 12.5 3.8 9.6 2.1 16.4 4.5 0.2 0.8 0.1 [mol %] Detachability evaluation A A A A A A A A A A C C A C Sealing Evaluation A A A A A A A B B C B A C A property Seal strength 18.1 10.5 11.5 20.9 29.5 7.5 27.5 5.4 4.6 0.5 6.4 24.4 1.4 24.4 [N/25 mm] Transparency evaluation A A A A A A A A A A A A C B Film adhesion evaluation A A A B A A B A A A B C A C *A = FTOHs, B = Perfluoroalkyl sulfonate salt, C = Tris(2.2.2-trifluoroethyl) phosphate, D = Dichloropentafluoropropane

[0185] From the results given above, the water-soluble film of the present invention has excellent detachability from the support as well as excellent sealing property and transparency. Adhesion of the films is also controlled. Since the water-soluble film of the present invention has excellent sealing property and transparency, it may be suitably used as chemical package films, base films for hydraulic pressure transfer, base films for embroidery, release films for artificial marble molding, seed package films, and films for waste storage bags. In particular, the water-soluble film of the present invention may be used as a chemical package film for chemicals such as pesticides, cleansers (including bleach), or disinfectants.