Composite sheet

Abstract

To provide a composite sheet by which a wet state caused by urine leakage or the like can be determined visually and easily when used for clothing, sheet or the like.SOLUTION: A composite sheet 1 according to the present invention comprises a surface layer on which a covering sheet 3, which is made of a material capable of absorbing water and colored in a single color same as a display sheet 2 colored in a predetermined single color or an unbleached color on a front side of the display sheet 2, is laminated, where the color of the display sheet 2 is a dark color having the color difference ΔE of 11 or more for the color of the covering sheet 3 having the water absorption ratio 0%, and the surface layer is a dark color in which a color expressed in the region of water absorption ratio 80% or more has the color difference ΔE of 1.5 or more for a color expressed in the region of water absorption ratio 0%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composite sheet that can be easily visually determined to be in a wet state. [Background technology]

[0002] With the advent of an aging society in recent years, the need for care for the increasing number of elderly people has become widely recognized as a social issue. Nursing care facilities for the elderly provide various types of care to help them live their daily lives, and for those requiring a high level of care, it is necessary to properly dispose of their excretions and maintain good hygiene in order to maintain their health.

[0003] In particular, elderly people tend to urinate more frequently but in smaller amounts, and for those requiring a high level of care, urination must be handled each time, but this inevitably increases the burden of checking whether or not the person has urinated.

[0004] Therefore, measures have been proposed to easily check whether or not urination has occurred. For example, Patent Document 1 describes a disposable diaper having a liquid-permeable topsheet, a liquid-impermeable backsheet, a liquid-absorbent core interposed between the topsheet and the backsheet, and an indicator means, and describes that the backsheet makes the indicator means difficult to see in a dry state and easy to see in a wet state. Furthermore, Patent Document 2 describes a disposable diaper having a liquid-permeable topsheet, a moisture-permeable and liquid-impermeable backsheet, and an absorbent body disposed between these two sheets, and describes that a member coated with an indicator that changes color when wet with urine is provided inside a semi-transparent region of the backsheet provided at least in the center of the crotch. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3533285 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-27884 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned patent documents, a disposable diaper is provided with an indicator that becomes visible when it is wet with urine, making it easy to check whether or not the diaper has urinated. However, when urine leaks from the diaper, it is desirable to change the wet clothes or sheets. However, in cases where a caregiver needs to check for urinary leakage, such as in the case of a care recipient with dementia, the caregiver must visually check the clothes or sheets to confirm their wetness.

[0007] Caregivers regularly check in this way and change the patient's clothes or sheets if there is any urinary leakage. However, there is a problem in that it is difficult to visually determine if the patient is wet when only a small amount of urine is leaking or when the leakage occurs around the groin area, which is difficult to check.

[0008] In particular, when the person being cared for is resting in bed and covered with a duvet, checking for urinary incontinence, etc., is necessary to protect the person's privacy, and the caregiver must lift the duvet from the side of the bed and look inside. However, it is dark inside the duvet, making it difficult and time-consuming to visually check the clothes and sheets, and in some cases the caregiver must check whether they are wet by touching them with their bare hands, which is one of the factors that puts a heavy burden on the caregiver.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a composite sheet that, when used for clothing, sheets, etc., allows easy visual detection of wetness due to urine leakage or the like. [Means for solving the problem]

[0010] The composite sheet of the present invention is a composite sheet having a surface layer in which a display sheet colored in a predetermined monochromatic system is laminated on the surface side with a cover sheet colored in the same monochromatic system as the display sheet or a raw bleached color made of a moisture-absorbent material, wherein the color of the display sheet is a dark color with a color difference ΔE (in accordance with JIS Z 8781-4:2013) of 11 or more relative to the color of the cover sheet when the hydration rate is 0%, and the surface layer is a dark color in which the color that appears in an area with a hydration rate of 80% or more has a color difference ΔE (in accordance with JIS Z 8781-4:2013) of 1.5 or more relative to the color that appears in an area with a hydration rate of 0%. [Effects of the Invention]

[0011] The composite sheet of the present invention has a surface layer in which a display sheet is colored a dark color with a color difference ΔE of 11 or more relative to the color of the covering sheet and a covering sheet is laminated on the surface side of the display sheet, and the color that appears in areas of the surface layer with a hydration rate of 80% or more is a dark color with a color difference ΔE of 1.5 or more relative to the color that appears in areas with a hydration rate of 0%.Therefore, the color of the display sheet appears in wet areas and is clearly different from the color of the covering sheet in non-wet areas, making it possible to easily determine the wet state visually.

[0012] Here, the hydration rate is a numerical value expressed as a percentage of the weight of added water relative to the weight of the test subject before the water is added when the test subject is impregnated with water. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a configuration of a composite sheet according to the present invention. [Figure 2] This is a color difference degree evaluation table using color difference ΔE as an index. [Figure 3] 1 is a table showing the relationship between the moisture content of the covering sheet alone and the diffuse transmittance of light. [Figure 4] 10 is a table showing the evaluation results of color difference ΔE in the case of a composite sheet using a cover sheet with a dye concentration of 0.03% owf. [Figure 5]10 is a table showing the evaluation results of color difference ΔE in the case of a composite sheet using a cover sheet with a dye concentration of 0.15% owf. [Figure 6] 10 is a table showing the evaluation results of color difference ΔE in the case of a composite sheet using a raw bleached color cover sheet. [Figure 7] 10 is a table showing the evaluation results of color difference ΔE for each color in the case of a composite sheet in which a display sheet and a cover sheet are combined. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below. Figure 1 is a schematic diagram showing a configuration of a composite sheet according to the present invention.

[0015] 1(a), the composite sheet 1 has a display sheet 2 colored in a predetermined monochromatic system and a cover sheet 3 laminated on its surface side, which is colored in the same monochromatic system as the display sheet 2 or in a raw bleached color to form a surface layer. In this case, the entire display sheet 2 may be colored in the predetermined monochromatic system, or only the surface side may be partially colored in the predetermined monochromatic system.

[0016] 1(b), the composite sheet 1' has a surface layer formed by laminating, on the surface side of a base sheet 21, a display sheet 22 colored in a predetermined monochromatic system and, on the surface side of the display sheet 22, a cover sheet 3 colored in the same monochromatic system as the display sheet 22 or a raw bleached color and made of a moisture-absorbent material. In this case, the base sheet 21 may be formed of multiple layers, and may be formed by laminating layers having various functions such as moisture permeability, breathability, and heat insulation.

[0017] In the following description, the term "dry state" refers to the state before hydration, and the term "hydrated state" or "wet state" refers to the state after hydration.

[0018] The base sheet 21 may also be a fabric made of a double-layered woven fabric, a double-layered knitted fabric, or a multi-layered nonwoven fabric, and may be made of a material with additional functions such as water absorption, sweat absorption, antibacterial and deodorizing properties, antibacterial properties, and antiviral properties, or may be processed to achieve these additional functions.

[0019] The display sheet 2 is formed into a sheet from a colored material or a material that can be colored, and examples thereof include sheets formed from known materials such as natural fibers, synthetic fibers, semi-synthetic fibers, and resin materials such as rubber, in known forms such as fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics, and films.

[0020] When used as a sheet, the display sheet 2 may be a waterproof sheet with moisture-permeable waterproof properties, or may have a multi-layer structure with a water-retaining layer and a waterproof layer, and it is desirable that it does not feel uncomfortable when laid between the sheets of bedding. Examples of materials for the waterproof sheet include urethane resin, rubber resin, acrylic resin, silicone resin, polyolefin resin, etc., and a water-repellent waterproof sheet may also be used.

[0021] The display sheet 2 can be formed by forming a monochromatic material into a sheet, or by forming a colorable material into a sheet and then coloring the entire sheet or only the surface of the sheet in a monochromatic color. The coloring method can be a known method such as dyeing or coating.

[0022] The color applied to the display sheet 2 is a dark color with a color difference ΔE (based on JIS Z 8781-4:2013) of 11 or more relative to the color of the covering sheet 3 with a 0% hydration rate. By using a dark color with a color difference ΔE of 11 or more, the color of the display sheet 2 can be easily distinguished visually from the color of the covering sheet 3.

[0023] The color of the indicator sheet 2 preferably has a fastness to washing test (based on JIS L 0844) of grade 4-5 or higher. By achieving a fastness of grade 4-5 or higher, when the composite sheet is used as clothing or a sheet, there is almost no color fading due to washing, and it becomes possible to easily visually determine the wet state over a long period of time.

[0024] The covering sheet 3 is formed into a sheet from a water-absorbent material, and examples thereof include sheets formed from known hydrophilic materials such as natural fibers, synthetic fibers, semi-synthetic fibers, and resin materials such as rubber in known forms such as fabrics, including woven fabrics, knitted fabrics, and nonwoven fabrics.

[0025] The covering sheet 3 may be used as is in the original white-based bleached color of the material, or may be colored in the same monochrome color as the display sheet 2 using a colored material or a colorable material, as with the display sheet 2. The color of the covering sheet 3 preferably has a fastness of 4-5 or higher in a washing fastness test (based on JIS L 0844).

[0026] The covering sheet 3 also has light transmittance that changes depending on the hydration rate, as will be described later. In the case of fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics, the light transmittance can be increased in a hydrated state compared to a dry state by adjusting the material, fiber shape, fineness, basis weight, thickness, structural organization, hue, color density, etc. Also, in the case of a film-like sheet, the surface can be made rough to reduce light transmittance, and the light transmittance can be increased by wetting the surface.

[0027] The surface layer is formed by laminating the cover sheet 3 in a state of close contact with the surface side of the display sheet 2. For example, an adhesive can be applied to the surface of the display sheet 2, and then the cover sheet 3 can be laminated and bonded to the surface. By applying the adhesive discretely, the composite sheet can be laminated while maintaining its stretchability and flexibility. Furthermore, when a thermoplastic resin material is used as the material for the display sheet 2 and / or the cover sheet 3, the two can be laminated in a state of close contact by discretely bonding them by heat fusion. Alternatively, the two can be laminated by sewing the whole together in a state of close contact.

[0028] The surface layer is designed so that the color that appears in areas with a hydration rate of 80% or more is a dark color with a color difference ΔE (based on JIS Z 8781-4:2013) of 1.5 or more compared to the color that appears in areas with a hydration rate of 0%. Therefore, in wet areas of the surface layer, the color of the indicator sheet 2 appears through the covering sheet 3, and the difference between this and the color of the covering sheet 3 that appears in non-wet areas is clear, making it possible to easily determine the wet state visually even in places where no light is irradiated, such as in a bedroom or under bedding while sleeping.

[0029] Specifically, the light transmittance of the cover sheet 3 is preferably such that the diffuse light transmittance (based on JIS K 7361) is 50% or less when the hydration rate is 0%, and the diffuse light transmittance (based on JIS K 7361) increases by 10% or more as the hydration rate increases when the hydration rate is 80% or more. As the diffuse transmittance increases with the hydration rate, it increases to 10% or more, making it possible to visually determine the degree of wetting based on the change in diffuse transmittance.

[0030] In a dry state with a water content of 0%, when the diffuse transmittance exceeds 50%, the color of the display sheet 2, which is darkly colored with a color difference ΔE of 11 or more relative to the color of the covering sheet 3, appears and can be visually confirmed, making it difficult to distinguish the difference from the color that appears in a wet state.

[0031] Furthermore, if the change in diffuse transmittance in a wet state (with a water content of 80% or more) is less than 10% compared to the dry state, it becomes difficult to visually distinguish the difference between the color that appears in the dry state and the color that appears in the wet state.

[0032] The change in diffuse transmittance in response to an increase in the hydration rate is preferably controlled by coloring the cover sheet 3 in a raw bleached color or at a dyeing concentration of less than 0.15% owf. If the dyeing concentration is 0.15% owf or more, the cover sheet 3 is colored darkly, and the change in diffuse transmittance in response to an increase in the hydration rate becomes small. Although the wet state can be determined, it becomes difficult to determine the change in the color appearance of the top sheet 2 depending on the degree of wetness.

[0033] The composite sheet described above is suitable for nursing care clothing and bedding. For example, if a care recipient experiences incontinence upon waking, it is difficult to tell that a small amount of moisture has adhered to the clothing, forcing the caregiver to rely on visual inspection, which is a burden. However, by using the composite sheet described above, the color change in the wet state becomes greater, making it easier to visually determine the wet state, making it possible to detect the wet state early and contributing to maintaining a good living environment for the care recipient. [Example]

[0034] <About setting the water content> The test subject was placed in a container whose weight had been measured in advance, and the weight was measured to calculate the weight of the test subject. Tap water was then added to the container in an amount calculated based on the hydration rate relative to the calculated weight of the test subject, and the test subject was thoroughly soaked in tap water to obtain a test subject with a predetermined hydration rate.

[0035] Furthermore, under standard conditions (temperature 20°C, humidity 65%), fiber materials with a 0% hydration rate before hydration contain moisture ranging from 0.4% to 15% depending on the type. However, under normal living conditions, if the test subject is placed in a wet state by adding liquid water at a hydration rate of 80% or more, it is believed that the moisture content before hydration will have little effect on the test.

[0036] <Calculation of color difference ΔE> Using a color difference meter (Konica Minolta CM-3600A, light source: D65), the color appearing on the surface of the test specimen was measured in accordance with JIS Z 8781-4:2013, and the color difference ΔE was calculated by calculating the distance between two points of color coordinates on the CIE 1976 L*a*b* color space using the following formula. ΔE(ΔE*ab)=[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2 It should be noted that ΔL*, Δa*, and Δb* are differences from B (Blank). FIG. 2 shows a color difference degree evaluation table using color difference ΔE as an index.

[0037] <Calculating diffuse light transmittance> Measurement was carried out using a haze meter (NDH5000 manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K 7361-1, and the total light transmittance and haze value obtained from the measurement results were multiplied together to calculate the diffuse transmittance (%).

[0038] <About washing fastness testing> The fabric was washed 50 times in a household washing machine (manufactured by Hitachi Consumer Marketing Co., Ltd.) in accordance with JIS L 0844, and its fastness was evaluated.

[0039] <About the test specimen> Multicolored color sheets (250mm long x 200mm wide x 0.02mm thick) were created as display sheets. The color sheets were made by blending pigments (blue, green, and pink, both from DIC Corporation) with a moisture-permeable urethane resin material (from DIC Corporation), producing a moisture-permeable waterproof film using a coating machine (from Hirano Tecseed Co., Ltd.), and cutting it into sheets of the specified size.

[0040] The color sheets were prepared in three monochrome colors: blue, green, and pink. Each color had three different densities: light, medium, and dark. The amount of pigment blended was adjusted so that the color difference ΔE was 11 or more relative to the color of the covering sheet described below.

[0041] The covering sheets were made of unbleached and multicolored fabrics (250mm length x 200mm width x 0.65mm thickness). The fabrics were made of processed polyester yarn (manufactured by Teijin Limited, 56 decitex, 36 filaments) and were knitted smoothly to a warp (course) density of 45 threads / inch, a weft (welt) density of 55 threads / inch, and a basis weight of 100g / m². 2 The fabric was knitted into a shape and cut into sheets of a predetermined size.

[0042] The covering sheets were colored in three monochrome colors: blue, green, and pink, similar to the color sheets. The coloring process was carried out using dyes (manufactured by Sumitomo Chemical Co., Ltd.; blue, green, pink) in a dyeing machine (manufactured by Texam Giken Co., Ltd.) under specified dyeing conditions (temperature 130°C, processing time 60 minutes). The dyeing concentration was set to three levels: 0.03% owf, 0.15% owf, and 0.75% owf, and the dyeing process was carried out in each color.

[0043] Figure 3 is a table showing the relationship between the hydration rate of the covering sheet alone and the diffuse transmittance of light. As the dye concentration increases from the raw bleached color of the covering sheet, the diffuse transmittance tends to decrease. When the dye concentration is less than 0.15% owf from the raw bleached color, the diffuse transmittance increases as the hydration rate increases above 80%. Compared to when the hydration rate is 0%, the diffuse transmittance increases by more than 10% up to a hydration rate of 240%. In contrast, at a dye concentration of 0.75% owf, there is almost no increase in diffuse transmittance as the hydration rate increases.

[0044] The reason why the increase in diffuse transmittance decreases as the dye concentration increases is thought to be because the light absorption by the dye increases. Therefore, when coloring the covering sheet, it was confirmed that by taking into account the increase in diffuse transmittance, the increase in diffuse transmittance can be made 10% or more as the hydration rate increases by setting the dye concentration to less than 0.15% owf.

[0045] Since the composite sheet is produced by overlaying a cover sheet on a display sheet and laminating them in a state of adhesion using adhesive or the like, it is preferable that the dye concentration of the cover sheet be less than 0.15% owf, so that the degree to which the color of the display sheet is revealed changes depending on the degree to which the composite sheet is wet.

[0046] <Combination of display sheet and covering sheet> The display sheet and cover sheet were each measured in the same monochrome combination in a dry state with a hydration rate of 0%, and the color difference ΔE between the two sheets was calculated.The two sheets were then laminated to form a composite sheet.The composite sheet was then changed from a dry state to a wet state, and the colors that appeared on the surface at hydration rates of 0%, 80%, 160%, and 240% were measured, and the color difference ΔE relative to a hydration rate of 0% was calculated.

[0047] For comparison, the color of the coating sheet alone was measured at 0%, 80%, 160% and 240% hydration, and the color difference ΔE relative to 0% hydration was calculated.

[0048] Figure 4 shows the evaluation results of the color difference ΔE in the case of a composite sheet using a cover sheet with a dye concentration of 0.03% owf, and Figure 5 shows the evaluation results of the color difference ΔE in the case of a composite sheet using a cover sheet with a dye concentration of 0.15% owf.

[0049] When the color of the display sheet was set to a dark color with a color difference ΔE of 11 or more compared to the color of the covering sheet with a hydration rate of 0%, the color of the composite sheet formed by laminating both sheets, in areas with a hydration rate of 80% or more, was a dark color with a color difference ΔE of 1.5 or more compared to the color that appeared in areas with a hydration rate of 0%, and was evaluated as a color that was different enough to detect a wet state.

[0050] In contrast, when the covering sheet is used alone, at a hydration rate of 80% or more, the color difference ΔE is often less than 1.5, making it difficult to determine whether the sheet is wet. In the case of a covering sheet with a dye concentration of 0.15% owf, the color difference ΔE is 1.5 or more, making it easy to determine whether the sheet is wet, but the increase in diffuse transmittance is small, making it difficult to determine the degree of wetness.

[0051] For the combination of a raw-bleached covering sheet and a colored display sheet, the colors were measured separately and the color difference ΔE between the two sheets was calculated, and then the two sheets were laminated to create a composite sheet. The composite sheet was then changed from a dry state to a wet state, and the color that appeared on the surface at hydration rates of 0%, 80%, 160%, and 240% was measured, and the color difference ΔE relative to a hydration rate of 0% was calculated. Figure 6 shows the evaluation results when a raw-bleached covering sheet was used.

[0052] Even when using a raw bleached colored covering sheet, by setting the color of the indicator sheet to a dark color with a color difference ΔE of 11 or more compared to the color of the covering sheet with a 0% hydration rate, the color that appears in the area with a hydration rate of 80% or more of the composite sheet becomes a dark color with a color difference ΔE of 1.5 or more compared to the color that appears in the area with a hydration rate of 0%, and it was evaluated as a color that was different enough to be able to sense the wet state.In contrast, with the covering sheet alone, almost no change in color difference ΔE due to changes in hydration rate was observed.

[0053] <About washing durability> The display sheet and cover sheet were measured for each color combination in a dry state with 0% water content, and the color difference ΔE between the two sheets was calculated. The two sheets were then laminated to create a composite sheet. The composite sheet was subjected to a washing fastness test to evaluate its fastness, and then dried. The fastness evaluation results were confirmed to be grade 4-5 or higher in all cases.

[0054] The dried composite sheet was changed from a dry state to a wet state to change the hydration rate, and the color that appeared on the surface at hydration rates of 0%, 80%, 160%, and 240% was measured, and the color difference ΔE relative to a hydration rate of 0% was calculated.

[0055] For comparison, the color of the unbleached covering sheet alone was measured at 0%, 80%, 160% and 240% hydration, and the color difference ΔE relative to 0% hydration was calculated.

[0056] FIG. 7 shows the evaluation results of the color difference ΔE for each color in the case of a composite sheet combining a display sheet and a cover sheet.

[0057] The composite sheet, which is a laminate of both sheets, exhibits a darker color in the area with a hydration rate of 80% or more, with a color difference ΔE of 1.5 or more compared to the color in the area with a hydration rate of 0%, confirming that the color remains different enough to detect the wet state.In contrast, with the covering sheet alone, almost no change in color difference ΔE was observed with changes in hydration rate. [Industrial Applicability]

[0058] The composite sheet of the present invention exhibits a dark color in areas of the surface layer with a hydration rate of 80% or more, with a color difference ΔE of 1.5 or more compared to the color in areas with a hydration rate of 0%, and the difference in color between wet and non-wet areas is clear, making it easy to visually distinguish the wet state. Therefore, by using this composite sheet in nursing care clothing and bedding, it is possible to improve the efficiency of nursing care work. For example, if a care recipient leaks excrement, the caregiver can visually check the wet state of the clothing or sheets and take appropriate action early.

[0059] Furthermore, since the composite sheet is washable, it can be easily visually determined whether it is wet even after repeated use, making it economically superior to disposable clothing, sheets, etc. [Explanation of symbols]

[0060] 1 Composite sheet, 2 Display sheet, 3 Covering sheet, 21 Base sheet, 22 Display sheet

Claims

1. A composite sheet having a surface layer in which a display sheet colored in a predetermined monochromatic system is laminated on the surface side thereof with a cover sheet colored in the same monochromatic system as the display sheet or in a raw bleached color and made of a moisture-absorbent material, wherein the color of the display sheet is a dark color with a color difference ΔE (in accordance with JIS Z 8781-4:2013) of 11 or more relative to the color of the cover sheet when the hydration rate is 0%, and the surface layer is a dark color in which the color that appears in an area with a hydration rate of 80% or more has a color difference ΔE (in accordance with JIS Z 8781-4:2013) of 1.5 or more relative to the color that appears in an area with a hydration rate of 0%.

2. 2. The composite sheet according to claim 1, wherein the covering sheet has a light diffuse transmittance (in accordance with JIS K 7361) of 50% or less when the hydration rate is 0%, and the light diffuse transmittance (in accordance with JIS K 7361) increases by 10% or more as the hydration rate increases when the hydration rate is 80% or more.

3. 3. The composite sheet according to claim 1 or 2, wherein the fastness in a washing fastness test (based on JIS L 0844) is grade 4-5 or higher, and after the test, the surface layer is a dark color in which the color that appears in an area with a hydration rate of 80% or more is a color difference ΔE (based on JIS Z 8781-4:2013) of 1.5 or higher relative to the color that appears in an area with a hydration rate of 0%.

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