Patent Application
20080075760
Hereinafter, the moisturized nonwoven fabric of the invention will be described in detail along with Examples.
Softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) was disintegrated by a pulper to produce pulp paper with about 30 g/m2 by a cylinder type paper manufacture machine. Rayon fibers (fineness 1.1 dtex×fiber length 38 mm) were disintegrated by two carding machines to produce a pair of fiber webs with about 10 g/m2 METSUKE. The above-mentioned pulp paper was sandwiched between the pair of fiber webs and fed to a conveyer belt. The pulp paper and the webs were subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt to obtain pulp-containing spunlace nonwoven fabric with about 52.4 g/m2 METSUKE. The water jet treatment was carried out using a nozzle having holes with a diameter of 80 μm at 1 mm pitches (a water jetting apparatus having small holes with a diameter of 0.08 mm and arranged in a row at 1 mm intervals) at water pressure of 4.5 MPa.
Then, the moisturized nonwoven fabric produced in the above-mentioned manner was moisturized. A moisturizing liquid was applied to the nonwoven fabric by a spray coating method. Three types of moisturized nonwoven fabrics were produced with having different amounts of the moisturizing liquid. After air dried and moisture conditioning, the obtained moisturized nonwoven fabrics were subjected to measurement to find that METSUKE was 68.4 (Example 1-1), 74.4 (Example 1-2), and 107.5 g/m2 (Example 1-3).
The moisturizing liquid was produced by mixing 60% by weight of glycerin, 10% by weight of sorbitol, 1% by weight of decaglycerin monostearic acid ester, 5% by weight of liquid paraffin, 1% by weight of polyoxyethylene (20 EO) sorbitan monostearate, 0.4% by weight of sorbitan monostearate, and 22.6% by weight of water.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 1.
Table 1 shows the results of property evaluation tests and sensory tests of Examples 1-1, 1-2, 1-3, and Comparative Example 1. The property evaluation tests and the sensory tests for Examples and Comparative Example were carried out as follows.
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Softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) was disintegrated by a pulper to produce pulp paper with about 30 g/m2 by a cylinder type paper manufacture machine. Mixed fibers containing 50% by weight of rayon fibers (fineness 1.1 dtex×fiber length 38 mm) and 50% by weight of PET fibers (fineness 1.1 dtex×fiber length 38 mm) were disintegrated by two carding machines to produce a pair of fiber webs with about 10 g/m2 METSUKE. The above-mentioned pulp paper was sandwiched between the pair of fiber webs and fed to a conveyer belt. The pulp paper and the webs were subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt to obtain pulp-containing spunlace nonwoven fabric with about 50.2 g/m2 METSUKE. The water jet treatment was carried out using a nozzle having holes with a diameter of 80 μm at 1 mm pitches and water pressure of 4.5 MPa.
Then, the nonwoven fabric produced in the above-mentioned manner was moisturized. The moisturizing liquid was applied to the nonwoven fabric by a spray coating method. Three types of treated nonwoven fabrics were produced by changing the application amounts of the moisturizing liquid. After air dried and moisture conditioning, the obtained moisturized nonwoven fabrics were subjected to measurement to find that METSUKE was 58.2 (Example 2-1), 71.6 (Example 2-2), and 103.7 g/m2 (Example 2-3). The moisturizing liquid was same as that used in Example 1.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 2.
Table 2 shows the results of property evaluation tests and sensory tests of Examples 2-1, 2-2, 3-3, and Comparative Example 2. The property evaluation tests and the sensory tests for Examples and Comparative Example were carried out as follows.
Softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) was disintegrated by a pulper to produce pulp paper with about 25 g/m2 by a cylinder type paper manufacture machine. Rayon fibers (fineness 1.7 dtex×fiber length 40 mm) were disintegrated by two carding machines to produce a pair of fiber webs with about 13 g/m2 METSUKE. The above-mentioned pulp paper was sandwiched between the pair of fiber webs and fed to a conveyer belt. The pulp paper and the webs were subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt to obtain pulp-containing spunlaced nonwoven fabric with about 51.7 g/m2 METSUKE. The water jet treatment was carried out using a nozzle having holes with a diameter of 100 μm at 1 mm pitches and water pressure of 5.0 MPa.
Then, the nonwoven fabric produced in the above-mentioned manner was moisturized. The moisturizing liquid was applied to the nonwoven fabric by a gravure coating method. After air dried and moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 70.1 g/m2. The moisturizing liquid was same as that used in Example 1.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 3.
Table 3 shows the results of property evaluation tests and sensory tests of Example 3 and Comparative Example 3. The property evaluation tests and the sensory tests for Example and Comparative Example were carried out as follows.
Softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) was disintegrated by a pulper to produce pulp paper with about 32 g/m2 by a cylinder type paper manufacture machine. Mixed fibers containing 50% by weight of rayon fibers (fineness 1.7 dtex×fiber length 40 mm) and 50% by weight of PET fibers (fineness 1.6 dtex×fiber length 44 mm) were disintegrated by one carding machine to produce fiber webs with about 14 g/m2 METSUKE. The above-mentioned pulp paper was laid on the fiber webs and fed to a conveyer belt. The pulp paper and the webs were subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt to obtain pulp-containing spunlace nonwoven fabric with about 45.5 g/m2 METSUKE. The water jet treatment was carried out using a nozzle having holes with a diameter of 100 μm at 1 mm pitches and water pressure of 3.5 MPa.
Then, the nonwoven fabric produced in the above-mentioned manner was moisturized. The moisturizing liquid was applied to the nonwoven fabric by a gravure coating method. After air dried and moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 57.0 g/m2. The moisturizing liquid was same as that used in Example 1.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 4.
Table 3 shows the results of property evaluation tests and sensory tests of Example 4 and Comparative Example 4. The property evaluation tests and the sensory tests for Example and Comparative Example were carried out as follows.
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Rayon fibers (fineness 1.7 dtex×fiber length 40 mm) were disintegrated by two carding machines and fed to a conveyer belt. The fibers were subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt to obtain a spunlace nonwoven fabric with 6.0 g/m2 METSUKE. The water jet treatment was carried out using a nozzle having holes with a diameter of 100 μm at 1 mm pitches and water pressure of 5.0 MPa.
Then, the nonwoven fabric produced in the above-mentioned manner was moisturized. The moisturizing liquid was applied to the nonwoven fabric by a gravure coating method. After air dried and moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 64.4 g/m2. The moisturizing liquid was same as that used in Example 1.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 5.
Table 4 shows the results of property evaluation tests and sensory tests of Example 5 and Comparative Example 5. The property evaluation tests and the sensory tests for Example and Comparative Example were carried out as follows.
A raw material mixture containing 50% by weight of softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) and 50% by weight of rayon fibers (fineness 1.7 dtex×fiber length 10 mm) was used to produce pulp paper by a short-net paper manufacture machine. The pulp paper was fed to a conveyer belt and subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt to obtain pulp-containing spunlace nonwoven fabric with 43.2 g/m2 METSUKE. The water jet treatment was carried out using a nozzle having holes with a diameter of 100 μm at 1 mm pitches and water pressure of 4 MPa.
Then, the nonwoven fabric produced in the above-mentioned manner was moisturized. The moisturizing liquid was applied to the nonwoven fabric by a gravure coating method. After air dried moisture conditioning, the obtained moisturizing nonwoven fabric was subjected to measurement to find that METSUKE was 56.4 g/m2. The moisturizing liquid was same as that used in Example 1.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 6.
Table 4 shows the results of property evaluation tests and sensory tests of Example 6 and Comparative Example 6. The property evaluation tests and the sensory tests for Example and Comparative Example were carried out as follows.
/cm2/sec
indicates data missing or illegible when filed
A raw material mixture containing 50% by weight of softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) and 50% by weight of rayon fibers (fineness 1.7 dtex×fiber length 10 mm) was used to produce pulp paper by a short-net paper manufacture machine. The pulp paper was fed to a conveyer belt and subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt to obtain pulp-containing spunlace nonwoven fabric with 51.1 g/m2 METSUKE. The water jet treatment was carried out using a nozzle having holes with a diameter of 100 μm at 1 mm pitches and water pressure of 4 MPa.
Then, the nonwoven fabric produced in the above-mentioned manner was moisturized. The moisturizing liquid was applied to the nonwoven fabric by a gravure coating method. After air dried moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 74.3 g/m2. The moisturizing liquid was same as that used in Example 1.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 7.
Table 5 shows the results of property evaluation tests and sensory tests of Example 7 and Comparative Example 7. The property evaluation tests and the sensory tests for Example and Comparative Example were carried out as follows.
The moisturizing liquid was applied to a commercialized cooking sheet (METSUKE 38.1 g/m2) by a gravure coating method. After air dried and moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 55.6 g/m2. The moisturizing liquid was same as that used in Example 1.
The nonwoven fabric before the moisturizing treatment (the pre-moisturized nonwoven fabric) was employed as Comparative Example 8.
Table 5 shows the results of property evaluation tests and sensory tests of Example 8 and Comparative Example 8. The property evaluation tests and the sensory tests for Example and Comparative Example were carried out as follows.
.98
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Each sample of the Examples was tested after a moisture conditioning in environments of 23° C. and 50% RH and subjected to evaluation according to JIS P8111 (standardized state for a moisture conditioning and a test for papers, sheets, and pulps).
The weight per unit surface area measured according to JIS L1913 (Test methods for nonwovens made of staple fibers) is defined as METSUKE.
The content (percentage) of the water-soluble component in the samples was measured according to the following procedure.
Five sheets of each sample prepared by cutting the sample in a size of 100 mm×100 mm were moisture conditioned in standardized conditions (23° C. and 50%) and weighed (the weight was defined as A, that is, A=total weight of the pre-moisturized nonwoven fabric, equilibrium moisture in the pre-moisturized nonwoven fabric, a moisture-retaining component and equilibrium moisture in the moisture-retaining component). The sample sheets were washed in 2 liter of distilled water at 60° C. for 10 minutes while being stirred and sufficiently dewatered. (If some of the fibers are depleted, the depleted fibers are filtered using a piece of filter paper. The obtained depleted fibers are processed similarly to the sample sheets of the nonwoven fabric and added to the weight B of the sample sheets of the nonwoven fabric.) Moreover, the water-soluble component was removed from the sample sheets by drying with a hot air dryer at 105° C. for three hours. Successively, the dried sheets were again moisture conditioned in standardized conditions (23° C. and 50%) and weighed (the weight was defined as B, that is, B=total weight of the pre-moisturized nonwoven fabric and equlibrium moisture in the pre-moisturized nonwoven fabric). The content (percentage) of the water-soluble component was calculated according to the following equation.
Water-soluble component content (%)=(A−B)/B×100
The measurement was carried out according to the following procedure with reference to JIS P8127 (Paper and board—Determination of moisture content—Oven-drying method).
Five sheets of each sample prepared by cutting the sample in a size of 100 mm×100 mm were moisture conditioned in standardized conditions (23° C. and 50%) and weighed (the weight was defined as A). Each sample sheet was put in a weighing bottle (cylindrical weighing bottle with 60 mm girth and 80 mm height) and closed there and weighed (the weight was defined as B). After a cover of the weighing bottle was opened, the sample sheet was dried with a hot air drier at 105° C. for 3 hours. Successively the cover was closed and the sample sheet was cooled to 23° C. in a desiccator and weighed (the weight was defined as C). The equilibrium moisture regain was calculated according to the following equation.
Equilibrium moisture regain (%)=(B−C)/A×100
The difference of the equilibrium moisture regain measured by the above-mentioned method between the moisturized nonwoven fabric and the nonwoven fabric from which the water-soluble component was removed (the pre-moisturized nonwoven fabric) is defined as an increase ratio of equilibrium moisture regain.
Increase ratio of equilibrium moisture regain (%)=(equilibrium moisture regain of moisturized nonwoven fabric)−(equilibrium moisture regain of nonwoven fabric from which the water-soluble component was removed)
The measurement was carried out according to JIS L1913 (Test methods for nonwovens made of staple fibers). The test was carried out in conditions of 50 mm sample width, 100 mm gripping intervals and 300 mm/min pulling speed. F5-value of each sample is the tensile strength measured at an elongation of 5%.
The water absorption amounts at a moment 5 seconds after starting the test, at a moment 10 seconds after starting, and at a moment of saturation were respectively measured by Larose method. The water absorption amount per 1 g of each sample was calculated by dividing the measured water absorption weight by the sample weight.
The water retention ratio was measured by the following method.
Each sample cut in a size of 100 mm×100 mm was moisture conditioned in standardized conditions (23° C. and 50%) and weighed (the weight was defined as A). After the sample was immersed in distilled water in a tray for 60 seconds, the sample was left on a metal net while being slanted at a tilting angle of 30° for 60 seconds and quickly subjected to weight measurement (the weight was defined as B). The water retention ratio was calculated according to the following equation.
Water retention ratio=(B−A)/A
Bending resistance standardized in JIS L1096 (Testing methods for woven fabrics) was measured by A method (45° cantilever method), E method (handle O meter method), and G method (drape coefficient). In the E method, the sample size was 100 mm×100 mm and measurement was carried out at the center of each sample. The slit width was set to be 10 mm.
The measurement was carried out using KES SE friction tester manufactured by Kato Tech Co., Ltd. A friction element (Silicone Sensor for KES SE, manufactured by Kato Tech Co., Ltd.) coated with silicon rubber was employed. The measurement was carried out for the front face and the rear face of each sample in vertical direction and transverse direction in conditions of 1 cm2 contact surface of the friction element; 25 gf/cm2 load, and 1 mm/sec sample stand moving speed. The average of all measured values was employed.
Bending rigidity B and hysteresis of bending moment 2HB were measured by KES FB 2 pure bending tester manufactured by Kato Tech Co., Ltd. The measurement was carried out in conditions of 200 mm sample width and standardized high sensitivity. If the sample size was smaller than 200 mm, the measurement may be carried out with 100 mm sample width.
The shear stiffness G and the hysteresis of sheet force at 0.5° of shear angle 2HG were measured by KES FB1 shear tester manufactured by Kato Tech Co., Ltd. The measurement was carried out in conditions of 200 mm sample width and standardized high sensitivity.
Qmax was measured by KES F7 TERHMO LABO manufactured by Kato Tech Co., Ltd. The measurement was carried out at a sample temperature of 20° C., a copper plate initial temperature of 30° C., and a contact pressure of 10 gf/cm2. The measurement was carried out for the front face and the rear face of each sample and the average of the measured values was employed.
The following items were evaluated by touching each sample with hands of 10 panelists.
Evaluation was carried out by calculating the total points in the following 4-point evaluation system: very soft=4 points; soft=3 points; slightly soft=2 points; and not soft=1 point.
The evaluation was carried out according to the following standard: “Very good” for 36-40 points; “Good” for 26 to 35 points; “Average” for 16 to 25 points; and “Poor” for 10 to 15 points.
The following respective items were evaluated in the same manner by calculating the total points and carrying out evaluation according to the similar standards.
Very smooth=4 points; smooth=3 points; slightly smooth=2 points; and not smooth=1 point
Very moist=4 points; moist=3 points; slightly moist=2 points; and not moist=1 point
The evaluation was performed on moisture felt in the skin when wiping hands with each sample sheet after washing the hands with water.
Strongly felt moist in skin=4 points; felt moist in skin=3 points; slightly felt moist in skin=2 points; and not felt moist in skin=1 point
The test was carried out assuming that stain around the eye is gently wiped so as not to irritate the eye. A circle of 1 cm in diameter is drawn with a marker in the middle of the palm assuming that the circle is an eye, and ketchup was applied to all over the palm. The evaluation was performed on the ease of wiping when ketchup outside the circle is wiped with each sample with care so as not to touch the ketchup in the circle.
Very good wiping property=4 points; good wiping property=3 points; slightly good wiping property=2 points; and inferior wiping property=1 point
As compared with nonwoven fabrics which were not subjected to moisturizing treatment, all of the nonwoven fabrics subjected to the moisturizing treatment were found having significantly improved properties of softness, smoothness, moist feeling, and the skin moisture retention. With respect to the stain wiping property for skin, although stains were removed even with the nonwoven fabrics of Comparative Examples, delicate work is difficult with the rough fabrics since they were inferior in smoothness and softness. Also, the physical irritation to the skin became significant.
Sample sheets with different amounts of the moisturizing liquid were produced in Examples 1 and 2. The sheets of Example 1-1 and Example 2-1 were sufficiently soft and gave dry feeling rather than moist feeling. As the application amount of the moisturizing liquid was increased, the moist feeling was more intensified. The sample sheets of Example 1-3 and Example 2-3 gave noticeable moisture retention feeling for the skin.
In the case the moisturizing treatment was carried out even for the nonwoven fabric produced by intense hydroentangling treatment just like the case of Example 3, the obtained moisturized nonwoven fabric had a pleasant texture.
In the case the moisturizing treatment was carried out even for the nonwoven fabric containing a large amount of pulp just like the case of Example 4, the nonwoven fabric was excellent in especially moist feeling and the nonwoven fabric also snowed excellent water absorption as well.
In the case the moisturizing treatment was carried out even for the nonwoven fabric containing no pulp just like the case of Example 5, the obtained moisturized nonwoven fabric was provided with further improved softness and also provided with moist feeling.
In the case the moisturizing treatment was carried out even for the nonwoven fabrics produced in wetlaid method just like the case of Examples 6 and 7, the obtained moisturized nonwoven fabrics had a pleasant texture.
In the case the moisturizing treatment was carried out even for the nonwoven fabric produced in the airlaid method just like the case of Example 8, the obtained moisturized nonwoven fabrics showed a progress in softness, moist feeling, and skin moisture retention.
Softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) was beaten and disintegrated to Canadian freeness of 680 ml to produce pulp paper with 32 g/m2 by a cylinder type paper manufacture machine.
Mixed fibers containing 50% by weight of rayon fibers (fineness 1.7 dtex×fiber length 40 mm) and 50% by weight of PET fibers (fineness 0.9 dtex×fiber length 44 mm) were fibrillated by a carding machine to produce fiber webs. METSUKE of a sheet of the fiber webs was controlled to be 14 g/m2.
The above-mentioned fiber webs was laid on the pulp paper and fed to a conveyer belt. The conveyer belt was made of a plastic net with 50 meshes and moved at about 7 m/min.
The pulp paper and the webs were subjected to entangling and uniting treatment by a water jet treatment apparatus installed on the path of the conveyer belt. The high pressure columnar current for the entangling treatment was generated using water as a fluid. Water jet machines each having nozzles with a diameter of 0.08 mm and arranged at 1 mm pitches in the transverse direction were arranged in three rows perpendicularly to the moving direction of the conveyer belt. The distance between the nozzles of the water jet machines and the surface of the layered sheet was set to be 2 cm. Water current at pressure of 2 MPa, 4 MPa, and 4 MPa was jetted from the three rows of the water jet machines. Successively, the hydroentangling treatment was carried out for the rear face of the layered sheet in the same conditions. The layered sheet for which the water jet treatment was finished was successively subjected to dewatering treatment and drying treatment. The obtained nonwoven fabric had 45 g/m2 METSUKE.
Then, the nonwoven fabric was moisturized. A moisturizing liquid was applied to the nonwoven fabric by a gravure coating method. After air drying and moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 58.5 g/m2. That is, the content of the water-soluble component was 30%.
The moisturizing liquid was produced by mixing 60% by weight of glycerin, 10% by weight of sorbitol, 1% by weight of decaglycerin monostearic acid ester, 5% by weight of liquid paraffin, 1% by weight of polyoxyethylene (20 EO) sorbitan monostearate, 0.4% by weight of sorbitan monostearate, and 22.6% by weight of water.
Softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) was beaten and disintegrated to Canadian freeness of 680 ml to produce pulp paper with 20 g/m2 by a cylinder type paper manufacture machine.
Mixed fibers containing 80% by weight of rayon fibers (fineness 1.7 dtex×fiber length 40 mm) and 20% by weight of PET fibers (fineness 0.9 dtex×fiber length 44 mm) were fibrillated by two carding machines to produce a pair of fiber webs. METSUKE of a sheet of the fiber webs was controlled to be 10 g/m2.
The above-mentioned pulp paper was sandwiched between the pair of fiber webs and fed to a conveyer belt. The conveyer belt was made of a plastic net with 20 meshes and moved at about 7 m/min.
The pulp paper and the webs were subjected to entangling treatment by a water jet treatment apparatus installed on the path of the conveyer belt, using high pressure columnar current. The high pressure columnar current was generated using water as a fluid. Water jet machines each having nozzles with a diameter of 0.08 mm and arranged at 1 mm pitches in the transverse direction were arranged in three rows perpendicularly to the moving direction of the conveyer belt. The distance between the nozzles of the water jet machines and the surface of the layered sheet was set to be 2 cm. Water current at pressure of 2 MPa, 4 MPa, and 4 MPa was jetted from the three rows of the water jet machines. Successively, the hydroentangling treatment was carried out for the rear face of the layered sheet in the same conditions. The layered sheet for which the water jet treatment was finished was successively subjected to dewatering treatment and drying treatment. The obtained nonwoven fabric had 40 g/m2 METSUKE.
Then, the nonwoven fabric was moisturized. The moisturizing liquid same as that used in Example 9 was applied to the nonwoven fabric by a gravure coating method. After air drying and moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 72 g/m2. That is, the content of the water-soluble component was 80%.
Softwood kraft pulp (Howe Sound 400, manufactured by Canfor Corporation) was disintegrated by a pulper to produce pulp paper with 25 g/m2 by a cylinder type paper manufacture machine. In this case, no beating treatment was carried out.
Rayon fibers (fineness 1.7 dtex×fiber length 40 mm) were fibrillated by two carding machines to produce a pair of fiber webs. METSUKE of a sheet of the fiber webs was controlled to be 13 g/m2.
The above-mentioned pulp paper was sandwiched between two sheets of the fiber webs and fed to a conveyer belt. The conveyer belt was made of a plastic net with 50 meshes and moved at about 7 m/min.
The pulp paper and the webs were subjected to entangling treatment by a water jet treatment apparatus installed on the path of the conveyer belt, using high pressure columnar current. The high pressure columnar current was generated using water as a fluid. Water jet machines each having nozzles with a diameter of 0.08 mm and arranged at 1 mm pitches in the transverse direction were arranged in three rows perpendicularly to the moving direction of the conveyer belt. The distance between the nozzles of the water jet machines and the surface of the layered sheet was set to be 2 cm. Water current at pressure of 3 MPa, 6 MPa, and 6 MPa was jetted from the three rows of the water jet machines. Successively, the hydroentangling treatment was carried out for the rear face of the layered sheet in the same conditions. The layered sheet for which the water jet treatment was finished was successively subjected to dewatering treatment and drying treatment. The obtained nonwoven fabric had 50 g/m2 METSUKE.
Then, the nonwoven fabric was moisturized. The moisturizing liquid same as that used in Example 1 was applied to the nonwoven fabric by a gravure coating method. After air drying and moisture conditioning, the obtained moisturized nonwoven fabric was subjected to measurement to find that METSUKE was 60 g/m2. That is, the content of the water-soluble component was 20%.
The nonwoven fabrics of the comparative Examples 9 to 11 were same as those of Examples 9 to 11 except that the nonwoven fabric were not subjected to moisturizing treatment and therefore they shows the properties of the raw nonwoven fabrics themselves.
The weight per unit surface area measured according to JIS L1913 (Test methods for nonwovens made of staple fibers) is defined as METSUKE.
Using the following equation, the density was calculated from the thickness measured similarly according to JIS L1913. The ambient conditions were controlled to a standardized state (temperature of 23° C. and humidity of 50% RH) according to JIS P8111 (Paper, board and pulps—Standard atmosphere for conditioning and testing).
Density (g/cm3)−METSUKE (g/m2)/thickness (μm)
The water-soluble component content is the increase ratio of METSUKE (density) due to the application of the moisturizing liquid and water to each nonwoven fabric in the moisturizing treatment.
As the water-soluble component content is higher, it means that the retention amount of the water-soluble components is higher. As the application amount of the moisturizing liquid is increased, the water-soluble component content is increased, however, since there are components which are evaporated and diffused after the moisturizing treatment and on the contrary, water may be taken in the water-soluble components from atmospheric air, the coating amount of the moisturizing liquid and the water-soluble component content are not necessarily accurately coincident with each other.
In the case A was defined as METSUKE of a nonwoven fabric before the moisturizing treatment measured according to JIS-L1913 and B was defined as METSUKE of the nonwoven fabric after the moisturizing treatment measured again according to JIS-L1913, the moisturizing liquid treatment ratio was calculated according to the following equation. The measurement conditions were same as the standardized state according to JIS-P8127 (23° C. and 50% RH).
Water-soluble component content (%)=(B−A)/A×100
The water activity value Aw of the nonwoven fabric is preferably 0.7 or lower in the standardized state (23° C. and 50% RH). If it is 0.7 or lower, propagation of mould and microorganism can be suppressed and thus there is no need to use a preservation or an anti-mold agent. For this purpose, it is preferable to add glycerin as a moisturizing component.
In the above-mentioned Examples, the water activity value was measured by a water activity meter (an electric resistance type hygrometer).
As the drape coefficient is smaller, the nonwoven fabric more fits with a hand of a user or the shape of an object to be wiped when the nonwoven fabric is used as a wiper. If the drape coefficient is high, the nonwoven fabric becomes stiff and uneasy to use.
In the above-mentioned Examples, the drape coefficient was measured by a drape tester (YD-100 model, manufactured by Daiei Kagaku Seiki Seisakusho) and calculated according to the following equation.
Drape coefficient (%)=[(Ad−S1)/(S2−S1)]×100
Ad: perpendicular projection surface area of sample (draping surface area)
S1: surface area of a sample stand (diameter 12.7 cm)
S2: surface area of a sample (diameter 25.4 cm)
The peak value of the heat flow Qmax is measured as heat quantity flexing at the moment of contact. If Qmax is high, it is felt cold at the moment of contact and if it is low, it is felt warm.
In the above-mentioned Examples, a measurement apparatus (KES F7 THERMO LABO II, manufactured by Kato Tech Co., Ltd.) was used to measure Qmax (the peak value of the heat flow). The measurement was carried out at a sample temperature of 20° C.; the copper plate initial temperature of 30° C.; and contact pressure of 10 gf/cm2.
If the breaking tenacity is too low, the nonwoven fabric may be torn at the time of use. If it is too high, the nonwoven fabric gives stiff feeling. The fracture elongation is preferably in a range from 10 to 150% in both vertical and transverse directions. If the fracture elongation is too low, the nonwoven fabric may be torn at the time of use and may not be deformed into the proper shape of the object to be wiped and thus becomes inconvenient for use.
In Examples, the measurement was carried out according to JIS L1913. The test was carried out in conditions of 100 nm gripping intervals and 300 mm/min pulling speed. MD/CD means the measured values in vertical direction/transverse direction, respectively.
The B value of Kawabata type feeling measurement value KES-FB 2 shows the bending stiffness (tilting at a curvature of 1 cm−1 in the bending test), and as the B value is higher, the bending stiffness is high and as it is lower, it means soft for bending.
The measurement was carried out by KES FB 2 pure bending tester manufactured by Kato Tech Co., Ltd. The measurement was carried out in conditions of 200 mm sample width and standardized high sensitivity. MD/CD means the same as that in elongation measurement.
The water absorption capability is preferably 0.1 ml or higher by saturated water absorption measurement by Larose method. If the water absorption capability is low, a large quantity of water remains after wiping in the case of using the nonwoven fabric as a wiper and therefore, it is not preferable.
In Examples, the saturated water absorption amount was measured by conventionally known Larose method.
The following items were evaluated by touching each sample with hands of ten panelists.
Evaluation was carried out by calculating the total points in the following 4-point evaluation system: very soft=4 points; soft=3 points; slightly soft=2 points; and not soft=1 point.
The evaluation was carried out according to the following standard: “Very good” for 36-40 points; “Good” for 26 to 35 points; “Average” for 16 to 25 points; and “Poor” for 10 to 15 points.
The following respective items were evaluated in the same manner by calculating the total points and carrying out evaluation according to the similar standards.
Very smooth=4 points; smooth=3 points; slightly smooth=2 points; and not smooth=1 point
Very moist=4 points; moist=3 points; slightly moist=2 points; and not moist=1 point
Strongly felt moist in skin=4 points; felt moist in skin=3 points; slightly felt moist in skin=2 points; and not felt moist in skin=1 point
(1) As compared with Comparative Examples 1 to 3 which were not subjected to the moisturizing treatment, Examples 9 to 11 subjected to the moisturizing treatment were found significantly excellent in the softness, smoothness, moist feeling, and skin moisture retention in the sensory test.
This can be understood by comparing the respective property values. The drape ratios of the nonwoven fabrics of Examples are small, showing that the nonwoven fabrics are easy to fit with hands and objects. The Qmax values are not so much different from those of Comparative Examples and the nonwoven fabrics of Examples are not felt unpleasantly cold even if they are brought into contact with the skin. KES B values are small and it means that the nonwoven fabrics are soft and flexible. Although the breaking tenacity values of Examples are smaller than those of Comparative Examples, the nonwoven fabrics of Examples have sufficient strength for practical use. The fracture elongation of the moisturized nonwoven fabrics of Examples is higher in all cases as compared with that of the nonwoven fabrics of Comparative Examples with the same number. The water absorption capability is lower than that of Comparative Examples. It is because the nonwoven fabrics of Examples already retain water.
(2) Comparing Examples 9 to 11 with each other, it can be understood that the properties and capabilities of the moisturized nonwoven fabrics are made different depending on the combination of fibers, treatment conditions of the hydroentangling treatment, and the like.
The relation between the moisturizing treatment ratio and capability was investigated.
The same nonwoven fabric was used as used in Example 9 and the nonwoven fabric was moisturized by the same manner as that of the Example 9, but the moisturizing treatment ratio was changed by changing the application amount of the moisturizing liquid.
(1) As the moisturizing treatment ratio, that is the amount of the water-soluble components, is increased from Example 14 to Example 12, the drape ratio is lowered and softness is increased. Since Qmax is increased, it is felt cold but not felt uncomfortable. KES B value is decreased to make bending easy.
(2) It is understood that the moisturized nonwoven fabric of Example 13 containing 80% by weight of the water-soluble component is better in comprehensive aspects than the moisturized nonwoven fabric of Example 14 containing 10% by weight of the water-soluble component.
The effects on the physical values and the sensory test were investigated by changing the addition amounts of components of the moisturizing liquid.
The moisturizing treatment was carried out for the same nonwoven fabric of Example 11 in the same manner as in Example 11, except that the addition amounts of components of the moisturizing liquid were changed.
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(1) All of the moisturizing liquids employed for Examples 15 to 19 are found efficacious, however it is understood the respective properties and the evaluations by the sensory test differ depending on the compositions of the moisturizing liquids.
(2) In the case sorbitol is added in addition to glycerin as a moisturizing agent, the softness is improved (Examples 16 to 19). In the case a glycerin fatty acid ester is added, the smoothness is improved (Examples 17 to 19). In the case oils are added, the softness and the moist feeling are improved (Examples 18 to 19). In the case silicones are added, smoothness is further improved (Example 19).
Properties were compared with those of commercialized wet tissue products.
Commercialized wet tissues (manufactured by Sanshoshigyo Co., Ltd.) were used.
Drying property: the respective samples were left in an atmosphere of constant temperature and constant humidity (23° C. and 50% RH) for 24 hours and the weight change was observed. The wet tissues were taken out of the container and immediately subjected to initial weight measurement.
Stimulus property: similarly to the above-mentioned sensory test, whether the skin was irritated or not was evaluated by the panelists by touching the samples.
Tests other than these tests were carried out similarly to the above-mentioned manner.
(1) The commercialized wet tissues of Comparative Example 12 have significant drying property and cannot be stored unless the storage is in an air-tight condition. The moisturized nonwoven fabric of Example 9 does not have drying property, there is no problem even if the moisturized nonwoven fabric is kept in an open state.
(2) It was proved that, as compared with the wet tissues of Comparative Example 12, the moisturized nonwoven fabric of Example 9 less irritates the skin, gives no uncomfortable cold feeling (Qmax is small), is excellent in the moisture retention feeling, and requires no preservative or the like (small water activity value).
Properties were compared with those of commercialized moisturizing tissue products.
Commercialized moisturized tissues (trade name: “Uruoi Hoshitsu”, manufactured by KAWANO PAPER Co., Ltd.) were used. Each tissue is two-ply paper produced by laminating two thin pulp paper sheets. The pulp used for the pulp paper does not contain fibers with a length exceeding 20 mm.
Water retention amount: Samples were immersed in water and left on a metal net tilted at 45° and the water weight was measured. The samples were left for 5 minutes.
Wiping property: stains were applied to the back of a hand and the remaining amounts were compared by eye observation when the stains were wiped using the samples. Ketchup was used for the stains. When the stains were sufficiently wiped off, it is given “good” evaluation. When the stains were not sufficiently wiped off, it is given “poor” evaluation.
METSUKE, tensile strength, and water absorption capability were measured according to JIS S3104. For Example 1, a test sample with a width of 50 mm was used, meanwhile two samples with a width of 25 mm were combined for the measurement in Comparative Example 5.
The test items other than these items were measured in the same manner as described above or by conventional methods.
(1) As compared with commercialized moisturized tissues of Comparative Example 13, the moisturized nonwoven fabric of Example 9 has high water retention amount, gives good skin touch and is excellent in the wiping property, as well as being excellent in strength.
This proves the technical advantage of the invention of using the nonwoven fabric containing fibers with a length of 20 mm or longer.
Properties of the moisturized nonwoven fabric of Example 9 were compared with those of commercialized nonwoven fabric products subjected to the same moisturizing treatment as Example 9.
A commercialized pulp nonwoven fabric (trade name: “Neoranu”, manufactured by KURESA CORPORATION) produced by the airlaid method was used. No fiber with a fiber length of 20 mm or longer was contained.
A commercialized wetlaid spunbonded nonwoven fabric (trade name: “Taiko TCF #503”, manufactured by Futamura Chemical Co., Ltd., fiber length: 10 mm) produced from rayon short fibers by wetlaid method was used. No fiber with a fiber length of 20 mm or longer was contained.
[Test Results]
(1) Comparative Examples 14 and 15 using the commercialized nonwoven fabrics were not improved in the moisture retention function even if the moisturizing treatment was carried out. It proved the technical advantage of the invention of using the specified nonwoven fabric.
(2) The moisturized nonwoven fabric of Example 9 was proved to have significantly improved properties in the sense of use such as the skin touch as compared with those of Comparative Examples 14 and 15.
(3) Comparative Example 14 (using the nonwoven fabric containing airlaid pulp in which fibers are fixed by chemical bonding) was inferior in the drape property. Actually, in the case it was used as a wiper, it gave stiff feeling and was difficult to deform along with the shape of the object to be wiped, and thus inferior in the sense of use.
(4) With respect to Comparative Example 15 (using the nonwoven fabric produced from rayon staple fibers by wetlaid spun bonding), the nonwoven fabric was still felt thin and hard in touching even after the moisturizing treatment and it was thus inferior in the sense of use.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-094451 | Mar 2006 | JP | national |
