WATER-SOLUBLE FILM AND PACKAGE

Abstract

[Problem to be solved] To provide a water-soluble film having good transparency and good releasability from a support with less surfactant content.

[Solution] A water-soluble film containing a polyvinyl alcohol resin and surfactant, wherein a content of the surfactant is 0.005 to 1 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin, and a ratio S(0)/S(32) of an abundance amount S(0) of the surfactant on at least one surface of the water-soluble film to an abundance amount S(32) of the surfactant on a cross-section surface at a depth of 32 nm from the at least one surface of the water-soluble film, measured by a count number of fragment ions derived from the surfactant detected by time-of-flight secondary ion mass spectrometry on the at least one surface of the water-soluble film, is in the range of 100 to 500.

Claims

1. A water-soluble film containing a polyvinyl alcohol resin and surfactant, wherein a content of the surfactant is 0.005 to 1 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin, and a ratio S(0)/S(32) of an abundance amount S(0) of the surfactant on at least one surface of the water-soluble film to an abundance amount S(32) of the surfactant on a cross-section surface at a depth of 32 nm from the at least one surface of the water-soluble film, measured by a count number of fragment ions derived from the surfactant detected by time-of-flight secondary ion mass spectrometry on the at least one surface of the water-soluble film, is in the range of 100 to 500.

2. The water-soluble film as claimed in claim 1, wherein the surfactant is a nitrogen-containing surfactant.

3. The water-soluble film as claimed in claim 2, wherein the nitrogen-containing surfactant contains at least one selected from the group consisting of an alkylamine-based surfactant, an alkylamide-based surfactant and an alkylalkanolamide-based surfactant.

4. The water-soluble film as claimed in claim 3, wherein the alkylamine-based surfactant is a polyoxyethylene alkylamine-based surfactant, and the alkylamide-based surfactant is a higher fatty acid diethanolamide-based surfactant.

5. The water-soluble film as claimed in claim 1 containing a filler.

6. The water-soluble film as claimed in claim 5, wherein the filler is inorganic particles.

7. A package in which the water-soluble film as claimed in claim 1 stores a chemical.

8. The package as claimed in claim 7, wherein the chemical is a pesticide, a detergent or a disinfectant.

9. The package as claimed in claim 7, wherein the chemical is in a liquid form.

Description

EXAMPLES

[0090] Hereinafter, the present invention will be specifically described below with reference to examples and the like, but the present invention is not limited by the following examples. Evaluation items and evaluation methods adopted in the following examples and comparative examples are as follows.

[TOF-SIMS Measurement]

[0091] The S(0) and the S(32) of the films obtained in the following examples or comparative examples were measured using the apparatus and the conditions described above to obtain S(0)/S(32).

[Peelability of Water-Soluble Film]

[0092] The peelability of the film from the support when forming the water-soluble film in Examples and Comparative Examples was evaluated according to the following criteria. A first drying roll was used as the support for peelability evaluation.

[0093] A: In the position in the circumferential direction of the support, the position where the film separates from the film-forming support is at approximately the same position in the width direction, and the peeling position is almost on a straight line when viewed in the width direction, and the film can be stably formed.

[0094] B: The position where the film separates from the support slightly fluctuates in the width direction, and the peeling position is uneven when viewed in the width direction, but stable film formation is possible.

[0095] C: The position where the film separates from the support fluctuates greatly in the width direction, and the film shows clear thickness unevenness, but continuous film formation is possible.

[0096] D: It is difficult to stably peel the film from the support, and the film cannot be continuously formed.

[Haze Value of Water-Soluble Film]

[0097] A straight line was drawn on the water-soluble film obtained in the following examples or comparative examples in the width direction (TD) of the film perpendicular to the film edge. 5 cm from both ends of the straight line of the film was removed, and the remaining portion was divided into 20 equal sections. Using the central portion of each of the 20 equally divided sections as the measurement point, a haze value at that measurement point was measured using a haze meter “HZ-1” manufactured by Suga Test Instruments Co., Ltd. according to ASTM D1003-61. In the following examples and comparative examples, the films with a width of 170 cm were formed, and the center portion of each section having a width of 8 cm obtained by dividing 160 cm into 20 equal sections with 5 cm removed from both ends was measured. The haze value of the water-soluble film was obtained by averaging the haze values obtained at 20 locations.

Example 1

[0098] 100 parts by mass of methyl maleate (MA)-modified PVA obtained by saponifying polyvinyl acetate (degree of saponification 99 mol %, degree of polymerization 1700, degree of MA modification 5 mol %), 10 parts by mass of glycerin as a plasticizer, 0.2 parts by mass of polyoxyethylene laurylamine as a surfactant and water were added to a dissolution tank and mixed at a maximum shear rate of 150 s.sup.−1 using a paddle-type stirring blade to prepare a film forming stock solution with a volatile content of 60% by mass. The resulting film forming stock solution was filtered, adjusted to a temperature of 95° C., discharged from a T-die at a maximum shear rate of 360 s.sup.−1 to a first drying roll having a surface temperature of 85° C., dried by blowing hot air of 85° C. at a speed of 5 m/second over the entire non-contact surface of a film to be formed with the first drying roll to obtain the film, and then peeled off the film from the first drying roll. The peelability of the film was A.

[0099] Drying the film was performed so that one surface and the other surface of the film peeled from the first drying roll are alternately in contact with the subsequent drying rolls, and the film was wound to obtain a water-soluble film (thickness 35 μm, width 170 cm).

[0100] When TOF-SIMS measurement of the obtained water-soluble film was performed, C.sub.3H.sub.7N.sub.2O.sup.+ ions were characteristically detected in comparison with a water-soluble film obtained in the same manner as described above without the addition of a surfactant (hereinafter, may be referred to as “control film”), and S(0) was 1980000 and S(32) was 6390 based on the ion count number. Therefore, S(0)/S(32) was 310. The haze of this water-soluble film was 0.6%.

Comparative Example 1

[0101] A water-soluble film was obtained in the same manner as in Example 1, except that the shape of the paddle-type stirring blade when preparing the film forming stock solution was changed to adjust the maximum shear rate to 350 s.sup.−1, the temperature of the film forming stock solution in the T die was changed to 85° C., and the lip opening of the T die was changed to adjust the maximum shear rate in the T die to 80 s.sup.−1. Table 1 shows the TOF-SIMS measurement results, the peelability and the haze of the water-soluble film. In the TOF-SIMS measurement, C.sub.3H.sub.7N.sub.2O.sup.+ ions were characteristically detected as compared with the control film.

Comparative Example 2

[0102] An attempt was made to prepare a film forming stock solution and form a film in the same manner as in Example 1, except that the amount of surfactant was changed to 0.001 parts by mass, but the peelability of the water-soluble film from the first drying roll was D, and the water-soluble film could not be stably obtained. Therefore, TOF-SIMS measurement and the haze measurement could not be performed.

Comparative Example 3

[0103] A water-soluble film was obtained in the same manner as in Example 1, except that the amount of surfactant was changed to 3 parts by mass. Table 1 shows the TOF-SIMS measurement results, the peelability and the haze of the water-soluble film. In the TOF-SIMS measurement, C.sub.3H.sub.7N.sub.2O.sup.+ ions were characteristically detected as compared with the control film.

Example 2

[0104] A water-soluble film was obtained in the same manner as in Example 1, except that the surfactant was changed to lauric acid diethanolamide. When the TOF-SIMS measurement of the obtained water-soluble film was performed, C.sub.4H.sub.10NO.sub.2.sup.+ ions were characteristically detected compared with the control film, and S(0)/S(32) was 440 from the count number of these ions. Table 1 shows the peelability and the haze of the water-soluble film.

Example 3

[0105] A water-soluble film was obtained in the same manner as in Example 1, except that the PVA was changed to unmodified PVA obtained by saponifying polyvinyl acetate (degree of saponification: 88 mol %, degree of polymerization: 1700). Table 1 shows the TOF-SIMS measurement results, the peelability and the haze of the water-soluble film. In the TOF-SIMS measurement, C.sub.3H.sub.7N.sub.2O.sup.+ ions were characteristically detected as compared with the control film.

Example 4

[0106] A water-soluble film was obtained in the same manner as in Example 2, except that the amount of surfactant was changed to 0.08 parts by mass. Table 1 shows the TOF-SIMS measurement results, the peelability and the haze of the water-soluble film. In the TOF-SIMS measurement, C.sub.4H.sub.10NO.sub.2.sup.+ ions were characteristically detected as compared with the control film.

Example 5

[0107] A water-soluble film was obtained in the same manner as in Example 4, except that 3 parts by mass of talc having an average particle size of 3 μm was added as a filler to the film forming stock solution. Table 1 shows the TOF-SIMS measurement results, the peelability and the haze of the water-soluble film. In the TOF-SIMS measurement, C.sub.4H.sub.10NO.sub.2.sup.+ ions were characteristically detected as compared with the control film.

Comparative Example 4

[0108] A water-soluble film was obtained in the same manner as in Example 2, except that the amount of the surfactant was changed to 0.8 parts by mass, the shape of the paddle-type stirring blade when preparing the film forming stock solution was changed to adjust the maximum shear rate to 75 s.sup.−1, and the lip opening of the T die was changed to adjust the shear rate in the T die to 1030 s.sup.−1. Table 1 shows the TOF-SIMS measurement results, the peelability and the haze of the water-soluble film. In the TOF-SIMS measurement, C.sub.4H.sub.10NO.sub.2.sup.+ ions were characteristically detected as compared with the control film.

TABLE-US-00001 TABLE 1 Composition of film Preparation PVA of film T die Modification forming Temperature Degree of Degree of Surfactant Filler stock of film Maximum TOF- saponifi- modifi- Content Content solution forming shear SIMS Evaluation cation cation (part by (part by Maximum stock rate S (0)/ Peel- Haze (mol %) Type (mol %) Type mass) Type mass) shear rate (s.sup.−1) solution (° C.) (s.sup.−1) S (32) ability (%) Example 1 99 MA 5 *1 0.2 — — 150 95 360 310 A 0.6 Example 2 99 MA 5 *2 0.2 — — 150 95 360 440 A 1.3 Example 3 88 — — *1 0.2 — — 150 95 360 280 A 0.5 Example 4 99 MA 5 *2 0.08 — — 150 95 360 330 B 0.7 Example 5 99 MA 5 *2 0.08 Talc 3 150 95 360 380 A 1.2 Comparative 99 MA 5 *1 0.2 — — 350 85 80  84 C 0.9 Example 1 Comparative 99 MA 5 *1 0.001 — — 150 95 360 — D — Example 2 Comparative 99 MA 5 *1 3 — — 150 95 360 280 A 2.8 Example 3 Comparative 99 MA 5 *2 0.8 — — 75 95 1030 570 A 2.9 Example 4 Surfactant *1: Polyoxyethylene laurylamine *2: Lauric acid diethanolamide

[0109] As shown in Table 1, the water-soluble film of the present invention has good peelability even with a relatively low surfactant content and has good transparency due to its low haze. The resulting water-soluble film can be suitably used for various water-soluble film applications. In particular, the water-soluble film of the present invention is suitable as a chemical packaging film, and suitable as a package for packaging pesticides, detergents (including bleach), disinfectants, and the like.