Adhesive base material

Abstract

The present invention aims to provide a highly durable adhesive base material comprising a nonwoven fabric whose constituent fibers consist solely of cellulose fibers. [Solution] A web laminate, whose constituent fibers consist solely of cellulose fibers, is subjected to a water-flow entanglement treatment while tension is applied in the longitudinal direction (the longitudinal direction of each web constituting the web laminate). By applying this water-flow entanglement treatment to the web laminate under tension, a nonwoven fabric with a strength of 39.2 N / 5 cm or more at 5% elongation in the longitudinal direction can be prepared. As a result, a substrate for adhesives with excellent strength can be prepared.

Description

[Technical Field]

[0001] This invention relates to a substrate for adhesive patches that has excellent strength. [Background technology]

[0002] For purposes such as providing anti-inflammatory and analgesic effects, cosmetic effects, or a warming or cooling sensation, adhesive patches (e.g., plasters) are used, which consist of a nonwoven fabric base material coated or impregnated with an adhesive and a plaster containing medicinal ingredients.

[0003] As a method for manufacturing such adhesive base materials, for example, Japanese Utility Model Publication No. 61-172127 (Patent Document 1) discloses a method for manufacturing a base material for poultice coating, which is made by simply entangling and integrating a fiber sheet having a longitudinal (unidirectional) fiber orientation, which is composed of short fibers such as cellulose fibers or synthetic fibers that will serve as the surface to which the ointment will be applied, with a fiber aggregate having these short fibers as its constituent fibers. Furthermore, as a specific example, the example in Patent Document 1 discloses the manufacture of a base material for poultice coating that uses polyester short fibers, viscose rayon short fibers, and polyolefin short fibers as constituent fibers. It should be noted that Patent Document 1 only discloses a drawing, shown as Figure 1, regarding the fiber orientation of the fiber aggregate, but this drawing does not disclose or suggest that the fiber aggregate has a specific fiber orientation. Furthermore, it is disclosed that the base material for poultice coating manufactured in this way has a longitudinal 5% modulus of 4 kg / 5 cm (converted to 39.2 N / 5 cm in the International System of Units) or more and exhibits excellent strength.

[0004] Furthermore, Patent Document 1 discloses a comparative example in which a base material for a patch was manufactured by replacing the fiber sheet having a longitudinal (unidirectional) fiber orientation, which serves as the surface to which the ointment is applied, with a fiber sheet having an oblique fiber orientation (i.e., a fiber layer having bidirectional fiber orientation). However, it is disclosed that the base material for a patch having a bidirectional fiber layer prepared in this way had a longitudinal 5% modulus of less than 4 kg / 5 cm (39.2 N / 5 cm when converted to the International System of Units). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] JITKAI SOH 61-172127 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The applicant has investigated a base material for adhesive patches that is rich in hydrophilicity and lipophilicity, providing excellent support for various ointments, and having a low environmental impact. This base material comprises a nonwoven fabric whose constituent fibers are solely cellulose fibers. Furthermore, in order to realize a base material for adhesive patches that is suitable for applications requiring strength, such as plastering agents, and that prevents unintended deformation such as excessive stretching when removing the patch, thereby making it easy to peel off, the applicant attempted to realize a base material for adhesive patches with excellent strength, based on the disclosure in Patent Document 1, comprising a nonwoven fabric with a strength at 5% elongation in the longitudinal direction (5% modulus in the longitudinal direction) of 39.2 N / 5 cm or more.

[0007] However, as is evident from Comparative Example 1, which will be described later, simply referring to the findings disclosed in Patent Document 1 does not necessarily guarantee the creation of a nonwoven fabric with a longitudinal stretch strength of 39.2 N / 5cm or higher and composed solely of cellulose fibers.

[0008] The present invention aims to provide a highly durable adhesive base material comprising a nonwoven fabric whose constituent fibers consist solely of cellulose fibers. [Means for solving the problem]

[0009] The first invention is "a base material for adhesive patches comprising a nonwoven fabric, wherein the constituent fibers of the nonwoven fabric consist solely of cellulose fibers, and the nonwoven fabric has a strength of 39.2 N / 5 cm or more when stretched by 5% in the longitudinal direction." The second invention is "the adhesive base material according to claim 1, wherein the nonwoven fabric comprises a fiber layer having a bidirectional fiber orientation." [Effects of the Invention]

[0010] The adhesive patch substrate according to the first invention comprises a nonwoven fabric whose constituent fibers consist solely of cellulose fibers. Therefore, it is a adhesive patch substrate that is rich in hydrophilicity and lipophilicity, has excellent support performance for various adhesives such as non-aqueous adhesives, and has a low environmental impact. Furthermore, the adhesive patch substrate according to the first invention comprises a nonwoven fabric with a strength of 39.2 N / 5cm or more when stretched by 5% in the longitudinal direction, thereby providing excellent strength.

[0011] Furthermore, when tension was applied to the adhesive base material, the length in the direction perpendicular to the direction in which the tension was applied became significantly shorter (significant width reduction occurred in the adhesive base material). As a result, in various manufacturing processes in which tension is applied to the adhesive base material, such as the process of unwinding the adhesive base material from a roll, the process of transporting the adhesive base material to the next process, and the process of applying or impregnating the adhesive base material with ointment, a secondary problem occurred in which significant width reduction occurred in the adhesive base material, making it difficult to manufacture the adhesive.

[0012] In response to the aforementioned secondary problems, the applicant has found that when the nonwoven fabric constituting the base material for the adhesive according to the first invention "has a fiber layer having bidirectional fiber orientation", significant width reduction is less likely to occur.

[0013] Therefore, in addition to being excellent in strength, the base material for the adhesive sheet according to the second invention is prevented from significant stretching.

Brief Description of the Drawings

[0014] [Figure 1] It is a drawing schematically showing a cross-section of a base material for a poultice coating, which discloses the fiber orientation of the fiber aggregate according to the invention of Patent Document 1.

Embodiments for Carrying Out the Invention

[0015] In the present invention, various configurations can be appropriately selected, such as the following configurations. In addition, various measurements described in the present invention are performed under temperature conditions of 25°C under normal pressure unless otherwise specified or defined. And, unless otherwise specified or defined, various measurement results described in the present invention are measured up to a value one digit smaller than the required value, and the required value is calculated by rounding off the obtained value. As a specific example, when the value up to the first decimal place is the required value, the value up to the second decimal place is obtained by measurement, and the value up to the first decimal place is calculated by rounding off the obtained value of the second decimal place, and this value is used as the required value. Also, the upper limit values and the lower limit values exemplified in the present invention can be arbitrarily combined.

[0016] The base material for the adhesive sheet according to the present invention includes a non-woven fabric. Since the non-woven fabric is rich in flexibility, it is a base material for an adhesive sheet that can realize an adhesive sheet with excellent adhesion, such as excellent followability to the human body. In addition, the non-woven fabric has voids formed by being surrounded by its constituent fibers. When a part of the paste enters the voids and the anchoring property is exhibited, it is possible to realize an adhesive sheet that prevents the paste from remaining on the human body when the adhesive sheet is peeled off.

[0017] The constituent fibers of the non-woven fabric are only cellulose-based fibers. Therefore, the base material for the adhesive sheet including the non-woven fabric is rich in hydrophilicity and lipophilicity, has excellent loading performance for various pastes such as non-aqueous adhesives, and has a low environmental load.

[0018] The cellulose-based fiber referred to here is a fiber composed mainly of cellulose and / or cellulose derivatives. Cellulose and cellulose derivatives may be of any origin, such as chemically synthesized products, plant-derived, regenerated cellulose, cellulose produced by bacteria, etc. Examples of cellulose-based fibers include rayon fiber, lyocell (registered trademark) fiber, polynosic fiber, cupra fiber, cotton fiber, hemp fiber, and the like.

[0019] The non-woven fabric can be prepared using a web made of cellulose-based fibers. For example, it can be prepared using a dry web formed by entangling cellulose-based fibers by feeding them to a carding device or an air-laying device, or a wet web formed by dispersing cellulose-based fibers in a dispersion medium and then forming them into a sheet by intertwining.

[0020] Then, the non-woven fabric can be prepared by integrating the constituent fibers by entangling and / or adhering the constituent fibers of the prepared web to each other. As a method for entangling and / or adhering the constituent fibers to each other, for example, a method of entangling by subjecting them to needle punching treatment or water flow entanglement treatment can be adopted. Also, a method of adhering the constituent fibers to each other using a binder can be adopted. Although known resins can be used as the binder, the binder may also contain additives such as flame retardants, fragrances, pigments, antibacterial agents, antifungal agents, photocatalytic particles, emulsifiers, dispersants, surfactants, thickeners, etc. in addition to resins.

[0021] However, since it is binderless, it is easy to provide an adhesive having excellent adhesion properties such as being able to support various pastes and having excellent conformability to the human body, it is preferable that the non-woven fabric is one in which the constituent fibers are integrated only by fiber entanglement.

[0022] The fineness and fiber length of the cellulose-based fibers constituting the non-woven fabric are not particularly limited, but in order to provide an adhesive having excellent adhesion properties such as excellent conformability to the human body, the fineness is preferably 0.5 to 7 dtex (decitex), more preferably 1 to 5 dtex, and still more preferably 1.3 to 2.2 dtex.

[0023] Furthermore, the cellulose fibers may be short fibers cut to a specific length or continuous fibers not cut to a specific length. However, it is preferable that the cellulose fibers be short fibers in order to facilitate the preparation of a strong adhesive base material. The fiber length of the short fibers is preferably 20 mm or more, more preferably 25 mm or more, and even more preferably 30 mm or more. On the other hand, if the fiber length exceeds 110 mm, fiber clumps tend to form in the nonwoven fabric, which may make it difficult to provide a strong adhesive base material. Therefore, it is preferable that the fiber length be 110 mm or less, and more preferably 60 mm or less. The above lower and upper limits can be arbitrarily combined as desired. Note that "fiber length" refers to the value measured in accordance with JIS L1015 (2010), 8.4.1c) direct method (Method C).

[0024] It is preferable for the nonwoven fabric to have through-holes so that it is gentle on the skin, highly breathable, and has good anchoring properties. In addition, it is possible to prepare a nonwoven fabric in which through-holes have been formed by increasing the force of the water flow in the water flow entanglement process described above.

[0025] The composition of the nonwoven fabric, including its basis weight and thickness, is not particularly limited and should be adjusted as appropriate. Basis weight: 10-350 g / m² 2 It can be 40-250g / m² 2 It can be 60-200g / m 2 It can be. In this invention, "basis length" refers to the main surface, which is the widest surface, 1 m 2 This can be determined by calculating the mass per unit area. The thickness can be 0.1 to 5 mm, 0.2 to 3 mm, or 0.3 to 1 mm. In this invention, "thickness" refers to the area of ​​5 cm² measured in the thickness direction relative to the main surface. 2 This refers to the arithmetic mean of the thickness obtained by measuring the thickness in a loaded area under a load of 0.98 N (= 100 gf) at five randomly selected locations. Such thickness measurements can be performed, for example, using a high-precision digital length measuring instrument (Mitutoyo Corporation, Lightmatic®).

[0026] The nonwoven fabric of the adhesive base material according to the present invention has a strength of 39.2 N / 5cm or more when stretched by 5% in the longitudinal direction. Here, the longitudinal direction refers to the direction parallel to the production direction of the nonwoven fabric (or adhesive base material) in the manufacturing process, if the manufacturing process of the nonwoven fabric (or adhesive base material) is known. If the manufacturing process of the nonwoven fabric (or adhesive base material) is not known, it refers to the direction parallel to the direction with the highest tensile strength, as determined by the following method.

[0027] (How to find the vertical direction) (Step 1) Take six rectangular samples (length of long side: 120 mm, length of short side: 50 mm) from the object to be measured, such as a nonwoven fabric or adhesive substrate, with the long sides of each sample differing by 30° in a direction parallel to the main surface of the object to be measured. (Step 2) Each sample collected is subjected to a constant-speed tensile testing machine (manufactured by Orientec, Tensilon, distance between chucks that grip the sample: 100 mm, length of the sample that must be held in the chuck for measurement: 10 mm, tensile speed: 50 mm / min.) in accordance with JIS P8113:2006 "Paper and cardboard - Test methods for tensile properties - Part 2: Constant-speed elongation method), and the sample is pulled in the direction of its long side to determine the maximum tensile load (unit: N / 50 mm) that acts on the sample until it breaks. (Step 3) As a result of performing the above-described (Step 2), the sample with the highest maximum tensile load (tensile strength, unit: N / 50mm) measured before fracture is selected. Then, the direction parallel to the long side of the selected sample on the object to be measured is defined as the vertical direction.

[0028] If a rectangular sample (length of the long side: 120 mm, length of the short side: 50 mm) cannot be taken from the object to be measured in (Step 1), the vertical direction of the object to be measured should be determined by the following method. (Step 1') Take six rectangular samples from the object to be measured, such as nonwoven fabric or adhesive substrate, so that their long sides are 30° apart from each other in a direction parallel to the main surface of the object to be measured, and the samples are of the maximum size (length of long side: 30 mm or more, length of short side: Y mm). (Step 2') Each sample collected is subjected to a constant-speed tensile testing machine (Orientec Co., Ltd., Tensilon, distance between chucks gripping the sample: 10 mm or more, tensile speed: 50 mm / min.) in accordance with JIS P8113:2006 "Paper and cardboard - Test methods for tensile properties - Part 2: Constant-speed elongation method), and the sample is pulled in the direction of the longer side until the distance between the chucks becomes 1.05 times that distance, and the maximum tensile load (unit: N / Y mm) acting on the sample during this time is determined, and this value is multiplied by 50 / Y to calculate the maximum tensile load (tensile strength, unit: N / 50 mm). (Step 3') As a result of performing the above-mentioned (Step 2'), the sample with the highest maximum tensile load (tensile strength, unit: N / 50mm) measured before fracture is selected. Then, the direction parallel to the long side of the selected sample on the object to be measured is defined as the vertical direction.

[0029] Generally speaking, the vertical direction of nonwoven fabric is • In the case of a nonwoven fabric having a fiber layer with a unidirectional fiber orientation, such as a fiber layer derived from a unidirectional web, the direction is parallel to the fiber orientation in the nonwoven fabric. Also, In the case of a nonwoven fabric having only two-directional fiber orientations, such as a nonwoven fabric composed solely of crosslay webs, or in the case of a nonwoven fabric not having a specific fiber orientation, such as a nonwoven fabric composed solely of random webs, the direction is parallel to the production direction of the nonwoven fabric.

[0030] In this context, a crosslay web is a web formed by folding unidirectional webs so that their fiber orientations do not overlap. Therefore, the fiber layer derived from a crosslay web has bidirectional fiber orientations.

[0031] The type of fiber orientation in the fiber layer of a nonwoven fabric can be determined by the following method.

[0032] (Method for confirming fiber orientation) (Step 1) A section containing a fiber layer is cut out from the object to be measured, such as a nonwoven fabric or a substrate for adhesives, to be used as a sample. (Step 2) The collected sample is fixed to a mounting board so that the main surface of the sample is exposed. Then, from among the fibers constituting the exposed main surface of the sample fixed to the mounting board, 20 or more fibers are randomly selected that, when viewed from the main surface side, have an angle greater than 0° and less than 90° clockwise with respect to the longitudinal direction mentioned above. The length direction of the fiber refers to the direction of the longer side of the smallest rectangle drawn to enclose the fiber in the microscope photograph or electron microscope photograph of the fiber in question. (Step 3) The standard deviation is calculated from the angle that the length direction of the fibers in the selected fibers makes with respect to the longitudinal direction and the average value thereof. At this time, if the value of the standard deviation is within 20, it is determined that the section containing the fiber layer that constitutes the object to be measured has a fiber orientation A that has an angle greater than 0° and less than 90° clockwise with respect to the longitudinal direction of the sample. (Step 4) From among the fibers constituting the exposed main surface of the sample fixed to the mounting board, 20 or more fibers are randomly selected that, when viewed from the main surface side, have an angle greater than 0° and less than 90° counterclockwise with respect to the longitudinal direction of the sample. (Step 5) The standard deviation is calculated from the angle that the length direction of the selected fibers makes with respect to the longitudinal direction of the sample, and its average value. If the value of the standard deviation is within 20, it is determined that the section containing the fiber layer that constitutes the object to be measured has a fiber orientation B that has an angle greater than 0° and less than 90° counterclockwise with respect to the longitudinal direction of the sample.

[0033] Based on the above assessment, if the measured sample has a main surface having only fiber orientation A or only fiber orientation B, it is determined that the object being measured has a fiber layer having a unidirectional fiber orientation. For example, a nonwoven fabric having a fiber layer derived from a unidirectional web has a fiber layer having such a unidirectional fiber orientation (fiber orientation A or fiber orientation B).

[0034] By incorporating a nonwoven fabric having a fiber layer with such unidirectional fiber orientation, this adhesive base material exhibits superior strength at 5% elongation in the longitudinal direction and superior tensile strength in the longitudinal direction.

[0035] Furthermore, if, as a result of the above assessment, the measured sample has a main surface having fiber orientation A and fiber orientation B, then the object to be measured is determined to have a fiber layer having two-directional fiber orientations. For example, a nonwoven fabric having a fiber layer derived from a crosslay web has a fiber layer having such two-directional fiber orientations (fiber orientation A and fiber orientation B).

[0036] This nonwoven fabric, which has a fiber layer with such bidirectional fiber orientation, is a base material for adhesive patches that is less prone to width reduction.

[0037] As a specific example, when a nonwoven fabric consisting of a web laminate in which a unidirectional web and a crosslay web are laminated is subjected to the above-described (method for confirming fiber orientation), it can be determined that the nonwoven fabric has a fiber layer having a unidirectional fiber orientation derived from the unidirectional web and another fiber layer having a bidirectional fiber orientation derived from the crosslay web. Such a specific example of a nonwoven fabric is preferable because it has superior strength due to the inclusion of a fiber layer derived from the unidirectional web. Furthermore, it is preferable that the nonwoven fabric is prevented from experiencing significant width reduction due to the inclusion of a fiber layer derived from the crosslay web.

[0038] Furthermore, if the measured sample has a main surface that does not have a specific fiber orientation, it is determined that the measured object has a fiber layer with a random fiber orientation. For example, a nonwoven fabric having a fiber layer derived from a random web has such a random fiber orientation.

[0039] Furthermore, the strength of a nonwoven fabric at 5% elongation in the longitudinal direction can be determined by the following method.

[0040] (Method for measuring strength at 5% elongation) (Step 1) Prepare a nonwoven fabric by removing unnecessary materials from the adhesive base material. (Step 2) The prepared nonwoven fabric is divided into three equal parts in the width direction (a direction perpendicular to the production direction). From the center of the width direction of each of the three divided nonwoven fabrics, one rectangular sample (length of the long side: 220 mm, length of the short side: 50 mm) is taken from each of the three divided nonwoven fabrics, for a total of three samples. At this time, if the nonwoven fabric has a fiber layer with a unidirectional fiber orientation, the unidirectional direction and the long side direction are made parallel. If the nonwoven fabric does not have a fiber layer with a unidirectional fiber orientation, the longitudinal direction and the long side direction of the nonwoven fabric are made parallel. (Step 3) The sample is subjected to a constant-speed tensile testing machine (Orientec Co., Ltd., Tensilon, distance between chucks that grip the sample: 200 mm, length of the sample that must be clamped in the chucks for measurement: 10 mm, tensile speed: 50 mm / min.) in accordance with JIS P8113:2006 "Paper and cardboard - Test methods for tensile properties - Part 2: Constant-speed elongation method), and the sample is pulled in the long-side direction until the distance between the chucks is 210 mm. The maximum stress (unit: N / 50 mm) measured during this time is then determined. (Step 4) Perform the above steps (1) to (3) on each sample, and the arithmetic mean of the obtained maximum stress is taken as the strength of the nonwoven fabric at 5% elongation in the longitudinal direction (unit: N / 50mm).

[0041] If a rectangular sample (length of the long side: 220 mm, length of the short side: 50 mm) cannot be obtained from the nonwoven fabric prepared in (Step 2), the longitudinal strength at 5% elongation (unit: N / 50 mm) of the nonwoven fabric shall be determined by the following method, which modifies the steps from (Step 2) onward. (Step 2') Divide the prepared nonwoven fabric into three equal parts in the width direction (a direction perpendicular to the production direction). From the center of the width direction of each of the three divided nonwoven fabrics, take one rectangular sample (length of the long side: 30 mm or more, length of the short side: Y mm) from each of the three divided nonwoven fabrics, for a total of three samples. Similarly, take a total of three rectangular samples. At this time, if the nonwoven fabric has a fiber layer with a unidirectional fiber orientation, ensure that the unidirectional direction and the long side direction are parallel. If the nonwoven fabric does not have a fiber layer with a unidirectional fiber orientation, ensure that the longitudinal direction and the long side direction of the nonwoven fabric are parallel. (Step 3') The sample is subjected to a constant-speed tensile testing machine (Orientec Co., Ltd., Tensilon, distance between chucks gripping the sample: 10 mm or more, tensile speed: 50 mm / min.) in accordance with JIS P8113:2006 "Paper and cardboard - Test methods for tensile properties - Part 2: Constant-speed elongation method), and the sample is pulled in the long-side direction until the distance between the chucks becomes 1.05 times that distance. The maximum stress (unit: N / Y mm) measured during this time is determined, and the value obtained by multiplying this value by 50 / Y is calculated. (Step 4') Perform the above steps (2') to (3') on each sample, and take the arithmetic mean of the value obtained by multiplying the maximum stress by 50 / Y as the strength of the nonwoven fabric at 5% elongation in the longitudinal direction (unit: N / 50mm).

[0042] The adhesive patch substrate according to the present invention has excellent strength because it comprises a nonwoven fabric with a strength of 39.2 N / 5cm or more when stretched 5% in the longitudinal direction. The strength of the nonwoven fabric when stretched 5% in the longitudinal direction is preferably 40 N / 5cm or more, more preferably 50 N / 5cm or more, even more preferably 60 N / 5cm or more, even more preferably 70 N / 5cm or more, even more preferably 80 N / 5cm or more, even more preferably 90 N / 5cm or more, and most preferably 100 N / 5cm or more, in order to provide an adhesive patch substrate with even greater strength. The upper limit can be adjusted as appropriate, but 400 N / 5cm is practical.

[0043] Furthermore, nonwoven fabrics with superior strength, exhibiting a strength of 39.2 N / 5 cm or higher when stretched 5% in the longitudinal direction, can be prepared by the manufacturing method described later.

[0044] The strength and basis weight of nonwoven fabrics are generally proportional; the strength increases proportionally as the basis weight increases. Therefore, by converting the 5% elongation strength in the longitudinal direction of the nonwoven fabric to a value per basis weight, the 5% elongation strength in the longitudinal direction of the nonwoven fabric can be evaluated more accurately, regardless of the basis weight. In other words, by dividing the numerical value of the 5% elongation strength in the longitudinal direction of the nonwoven fabric (unitless) by the numerical value of the nonwoven fabric's basis weight (unitless), the strength of the nonwoven fabric can be determined more accurately.

[0045] Therefore, the numerical value of the strength of the nonwoven fabric at 5% elongation in the longitudinal direction per basis weight should be high, preferably 0.069 or higher, preferably higher than 0.089, more preferably 0.090 or higher, and most preferably 0.100 or higher, in order to make the nonwoven fabric stronger. The upper limit can be adjusted as appropriate, but 0.400 is a realistic value.

[0046] Furthermore, the 5% elongation strength in the transverse direction perpendicular to the longitudinal direction of the nonwoven fabric on the main surface of the nonwoven fabric can be adjusted as appropriate. The higher the 5% elongation strength in the transverse direction, the stronger the nonwoven fabric. Therefore, the adhesive base material has superior strength due to the presence of this nonwoven fabric. The 5% elongation strength in the transverse direction of the nonwoven fabric is preferably 6.8 N / 5 cm or higher, more preferably 8 N / 5 cm or higher, and even more preferably 10 N / 5 cm or higher, to ensure that the adhesive base material has superior strength. The upper limit can be adjusted as appropriate, but 100 N / 5 cm is practical.

[0047] Furthermore, in the nonwoven fabric, the 5% elongation strength in the transverse direction is determined in (Step 2) or (Step 2') of the (Method for Measuring 5% Elongation Strength) described above. If the nonwoven fabric has a fiber layer with unidirectional fiber orientation, the unidirectional direction and the long side direction are perpendicular to each other. If the nonwoven fabric does not have a fiber layer with unidirectional fiber orientation, the 5% elongation strength in the transverse direction (unit: N / 50mm) of the nonwoven fabric is determined by using a rectangular sample taken with the longitudinal direction and the long side direction of the nonwoven fabric perpendicular to each other.

[0048] To create a base material for adhesives that is resistant to tearing when applied incorrectly or when removed after use, the nonwoven fabric preferably has a breaking strength of 50 N / 50 mm or more in both the longitudinal and transverse directions, more preferably 100 N / 50 mm or more, even more preferably 200 N / 50 mm or more, and even more preferably 500 N / 50 mm or more. The upper limit can be adjusted as appropriate, but 700 N / 50 mm is practical.

[0049] The longitudinal breaking strength of a nonwoven fabric can be determined by the following method.

[0050] (Method for measuring fracture strength) (Step 1) Prepare a nonwoven fabric by removing unnecessary materials from the adhesive base material. (Step 2) Divide the prepared nonwoven fabric into three equal parts in the width direction (a direction perpendicular to the production direction). From the center of each of the three divided nonwoven fabrics in the width direction, take one rectangular sample (length of the long side: 220 mm, length of the short side: 50 mm) from each of the three divided nonwoven fabrics, for a total of three samples. In this case, if the nonwoven fabric has a fiber layer having a unidirectional fiber orientation, the unidirectional direction and the long side direction should be parallel. If the nonwoven fabric does not have a fiber layer having a unidirectional fiber orientation, the longitudinal direction and the long side direction of the nonwoven fabric should be parallel. (Step 3) The sample is subjected to a constant-speed tensile testing machine (manufactured by Orientec, Tensilon, distance between chucks that grip the sample: 200 mm, length of the sample that must be held in the chuck for measurement: 10 mm, tensile speed: 50 mm / min.) in accordance with JIS P8113:2006 "Paper and cardboard - Test methods for tensile properties - Part 2: Constant-speed elongation method), and the sample is pulled in the direction of its long side, and the maximum load (unit: N / 50 mm) acting on the sample until the sample breaks is determined. (Step 4) Perform the above steps (1) to (3) on each sample, and the arithmetic mean of the obtained maximum loads will be taken as the maximum longitudinal load (unit: N / 50mm) in the nonwoven fabric.

[0051] If a rectangular sample (length of the long side: 220 mm, length of the short side: 50 mm) cannot be obtained from the nonwoven fabric prepared in (Step 2), the maximum longitudinal load (unit: N / 50 mm) in the nonwoven fabric shall be determined by the following method, which modifies the steps from (Step 2) onward. (Step 2') Divide the prepared nonwoven fabric into three equal parts in the width direction (a direction perpendicular to the production direction). From the center of the width direction of each of the three divided nonwoven fabrics, take one rectangular sample (length of the long side: 30 mm or more, length of the short side: Y mm) from each of the three divided nonwoven fabrics, for a total of three samples. Similarly, take a total of three rectangular samples. At this time, if the nonwoven fabric has a fiber layer with a unidirectional fiber orientation, ensure that the unidirectional direction and the long side direction are parallel. If the nonwoven fabric does not have a fiber layer with a unidirectional fiber orientation, ensure that the longitudinal direction and the long side direction of the nonwoven fabric are parallel. (Step 3') The sample is subjected to a constant-speed tensile testing machine (Orientec Co., Ltd., Tensilon, distance between chucks gripping the sample: 10 mm or more, tensile speed: 50 mm / min.) in accordance with JIS P8113:2006 "Paper and cardboard - Test methods for tensile properties - Part 2: Constant-speed elongation method" to pull the sample in the direction of its long side, and the maximum load (unit: N / Y mm) acting on the sample until it breaks is determined, and this value is multiplied by 50 / Y to calculate the value. (Step 4') Perform the above steps (2') to (3') on each sample, and take the arithmetic mean of the value obtained by multiplying the maximum load by 50 / Y as the maximum longitudinal load in the nonwoven fabric (unit: N / 50mm).

[0052] Furthermore, in the nonwoven fabric, the maximum lateral load is determined in (Step 2) or (Step 2') of the (Method for Measuring Breaking Strength) described above, such that if the nonwoven fabric has a fiber layer with unidirectional fiber orientation, the unidirectional direction and the long side direction are perpendicular to each other. Furthermore, if the nonwoven fabric does not have a fiber layer with unidirectional fiber orientation, the longitudinal direction and the long side direction of the nonwoven fabric are perpendicular to each other.

[0053] The base material for the adhesive patch may include other materials besides the nonwoven fabric described above (for example, fabric, porous film, or breathable foam). However, as mentioned above, it is preferable for the base material for the adhesive patch to be composed solely of nonwoven fabric, as this makes it easier to provide an adhesive patch with excellent conformability to the human body and a superior feel when applied.

[0054] The composition of the adhesive base material, including its weight and thickness, is not particularly limited and should be adjusted as appropriate. The weight should be between 10 and 350 g / m². 2 It can be 40-250g / m² 2 It can be 60-200g / m 2 It can be as follows: The thickness can be 0.1-5 mm, 0.2-3 mm, or 0.3-1 mm.

[0055] Furthermore, the base material for the patch may have information such as the source, active ingredients, or design printed on it. In addition, the base material for the patch may be colored with pigments or dyes.

[0056] The method for manufacturing the adhesive base material of the present invention will be explained with an example. The method for manufacturing the adhesive base material of the present invention can be appropriately selected, for example, (Step 1) A step of preparing a unidirectional web using cellulose fibers, (Step 2) A step to prepare a crosslay web by folding a unidirectional web prepared using cellulosic fibers in such a way that the fiber orientations do not overlap. (Step 3) A step to prepare a web laminate by stacking the prepared unidirectional web and the prepared crosslay web so that their respective longitudinal directions are parallel. (Step 4) A process in which tension is applied to the web laminate in a direction parallel to the longitudinal direction of each web, and a water flow entanglement treatment is applied to entangle the constituent fibers of the web laminate. (Step 5) A step to prepare a nonwoven fabric by drying the web laminate after the water entanglement treatment. It can be equipped with.

[0057] In step 4, the manner of water flow entanglement applied to the web laminate is adjusted as appropriate. The pressure of the water flow applied to the web laminate can be 0.1 to 20 MPa, 0.5 to 18 MPa, or 1 to 15 MPa. Water flow entanglement may be applied from only one main surface side of the web laminate, from both main surfaces simultaneously, or from one main surface side first, and then from the other main surface side. Furthermore, water flow entanglement may be applied to the web laminate multiple times. By employing water flow entanglement treatment, the constituent fibers can be more strongly entangled and integrated, and a nonwoven fabric that is less prone to delamination can be prepared.

[0058] Furthermore, when applying a water flow to the web laminate, it is preferable to remove excess water from below the web laminate by suction.

[0059] This manufacturing method is characterized by applying a water-flow entanglement treatment to a web laminate under tension in its longitudinal direction (the longitudinal direction of each web constituting the web laminate). By applying this water-flow entanglement treatment to the web laminate under tension, a nonwoven fabric with a strength of 39.2 N / 5cm or higher at 5% elongation in the longitudinal direction can be prepared. As a result, a substrate for adhesives with excellent strength can be prepared.

[0060] The nonwoven fabric having a fiber layer with unidirectional fiber orientation makes it easy to prepare a nonwoven fabric with a longitudinal stretch strength of 39.2 N / 5cm or more at 5% elongation, and the nonwoven fabric having a fiber layer with bidirectional fiber orientation makes it easy to prepare a nonwoven fabric that prevents significant width reduction.

[0061] The method for applying tension to the web laminate can be appropriately selected, but for example, a method can be adopted in which tension is applied to the web laminate in a direction parallel to its longitudinal direction by increasing the speed at which the web laminate is transported after the water entanglement treatment compared to the speed at which the web laminate is subjected to the water entanglement treatment. In this case, the speed at which the web laminate is transported after the water entanglement treatment is faster than 1.0 times the speed at which the web laminate is subjected to the water entanglement treatment, and preferably 1.1 to 2 times faster.

[0062] In step 5, the method for drying the web laminate after the water entanglement treatment can be appropriately selected. For example, a method of drying by subjecting it to heat treatment can be adopted. For example, methods such as heating or heating and pressurizing with a roll, heating by subjecting it to a heating device such as an oven dryer, far-infrared heater, dry heat dryer, or hot air dryer, or heating by irradiating with infrared rays under no pressure can be used.

[0063] The nonwoven fabric obtained as described above can be used as a base material for adhesives on its own, but a base material for adhesives may also be prepared by laminating a cover material, support, etc. Known materials can be used for the cover material and support, such as woven fabric, porous film, or breathable foam. Alternatively, the base material for adhesives may simply consist of the nonwoven fabric with the cover material and support layered on top. Alternatively, the nonwoven fabric and the cover material and support may be interlayer-bonded by fusion of a binder, hot-melt web, or the constituent materials of the cover material and support, or by bonding through an adhesive treatment such as heat sealing or ultrasonic welding.

[0064] The external shape of the adhesive substrate can be adjusted as appropriate and is not particularly limited. In addition to having a continuous length in the production direction and being the shape of a roll of raw material wound on a roll, it can also be, for example, a square shape with rounded corners, a circle, or an ellipse. Furthermore, the adhesive substrate may have cut-out sections, punched sections, or notches.

[0065] A patch can be prepared by applying an ointment to at least one main surface of the adhesive base material of the present invention. Alternatively, the ointment may be present on one main surface of the adhesive base material and may also penetrate inward from that main surface. Furthermore, the ointment may be present throughout the entire adhesive base material.

[0066] The constituent materials of the ointment are not particularly limited, but it is preferable that it contains an adhesive that has adhesive strength capable of fixing the drug to the skin surface for a long period of time at room temperature. Examples of such adhesives include rubber-based adhesives, acrylic-based adhesives, and silicone-based adhesives. Among these, rubber-based adhesives are preferred from the viewpoint of good adhesive properties and drug release, and in particular, natural rubber, synthetic isoprene rubber, polyisobutylene, polyvinyl ether, polyurethane, polyisoprene, polybutadiene, styrene-butadiene copolymer, styrene-isoprene copolymer, and styrene-isoprene-styrene block (SIS) copolymer are more preferably used. These can be used individually or in combination of several types.

[0067] The paste can contain medicinal components. Since the types thereof are appropriately selected according to the usage of the patch, they are not particularly limited. For example, in the case of a patch for therapeutic purposes, they can be functional components such as antipyretic, analgesic and anti-inflammatory agents, cardiotonics, vitamins, heart medications (vasodilators), bronchodilators, local anesthetics, antipruritics, agents for purulent diseases, hormonal agents and the like. Further, in the case of a patch for beauty effects, they can be functional components with a mild effect on the human body, which are defined as quasi-drugs, cosmetics such as beauty components and the like. Furthermore, in the case of a patch for warming effects, they can be functional components such as capsicum extract, benzyl nicotinate and the like. Alternatively, in the case of a patch for cooling effects, they can be functional components such as cooling agents including water-containing gels, menthol and the like.

Examples

[0068] Examples of the present invention are described below, but the present invention is not limited to the following examples.

[0069] (Comparative Example 1) 100% by mass of rayon fiber (fiber fineness: 1.7 dtex, fiber length: 40 mm), which is a cellulose-based fiber, is fed to a carding machine for fibrillation to prepare a unidirectional web (basis weight: 30 g / m 2 ). Further, the unidirectional webs prepared in the same manner are folded so that the fiber orientations do not overlap to prepare a cross-laid web (basis weight: 70 g / m 2 ). Next, the unidirectional web and the cross-laid web are laminated to prepare a web laminate. At this time, the longitudinal direction of the unidirectional web and the longitudinal direction of the cross-laid web are made parallel. With the longitudinal directions of the unidirectional web and the cross-laid web constituting the web laminate and the conveyance direction of the web laminate being parallel, the web laminate is fed to a water entanglement device to subject both main surfaces of the web laminate to water entanglement to entangle the constituent fibers with each other. Note that the speed at which the web laminate is fed to the water entanglement device is made equal to the speed at which the web laminate is conveyed after passing through the water entanglement device. Subsequently, the web laminate, which had undergone water entanglement, was dried by subjecting it to a hot air dryer to prepare a nonwoven fabric.

[0070] (Example 1) A nonwoven fabric was prepared in the same manner as in Comparative Example 1, except that the speed at which the web laminate was transported after passing through the water entanglement device was increased to 1.1 times the speed at which the web laminate was fed into the water entanglement device, thereby applying tension to the web laminate in the transport direction, which is its production direction (a direction parallel to the longitudinal direction of the unidirectional web and crosslay web), while the water entanglement treatment was performed.

[0071] Table 1 summarizes the composition and properties of the nonwoven fabrics prepared in Comparative Example 1 and Example 1. In addition, the nonwoven fabrics prepared in Comparative Example 1 and Example 1 were used as base materials for adhesives and their performance was evaluated by subjecting them to the following evaluation methods.

[0072] (Method for evaluating strength) A PET film was prepared with one main surface coated with a silicone release agent. Then, a layer of pseudo-ointment (thickness: 100 μm) having the following composition was applied to the main surface of the PET film coated with the silicone release agent. In this way, a PET release film was prepared. (Composition of the pseudo-ointment) Styrene / isoprene / styrene block copolymer: 4 parts by mass Polyisobutylene: 24 parts by mass Hydrogenated rosin ester: 30 parts by mass Liquid paraffin: 40 parts by mass Then, the main surface derived from the crosslay web of the adhesive substrate and the layer of pseudo-ointment on the PET release film were superimposed, and the mixture was then subjected to a press, thereby applying heat and pressure (press temperature: 100°C, press pressure: 0.1 MPa) between the two main surfaces. After that, the laminate of the adhesive substrate and the PET release film was allowed to cool, and the adhesive was prepared. Subsequently, nine sections (square, 70 mm vertically, 100 mm horizontally) were taken from the prepared patch, and the PET release film was peeled off each section. Then, one exposed imitation ointment layer was applied to the upper arm of each of the nine subjects, and the subjects peeled off the patch in a direction parallel to the vertical direction of the unidirectional web and crosslay web that constitute the base material of the patch. The table shows the number of subjects (in units of subjects) who evaluated the patch as easy to remove without unintended deformation, such as excessive stretching of the adhesive base material, when the subject removed it. The "Strength Evaluation" column indicates this. The more subjects who evaluated the patch as easy to remove, the stronger the adhesive base material constituting that patch is.

[0073] (Method for evaluating the degree of reduction) A sample piece measuring 300 mm on the long side and 50 mm on the short side is taken from the adhesive patch substrate. When taking the sample piece, ensure that the longitudinal direction and the long side direction of the unidirectional web and crosslay web constituting the adhesive patch substrate are parallel. Next, a constant-speed elongation tensile testing machine (manufactured by Orientec, Tensilon, distance between chucks (gripping distance) 200 mm, tensile speed: 100 mm / min) is used to pull the sample piece in the long-side direction with a force of 40 N / 50 mm. Then, at the point when the force pulling the sample piece in the long-side direction reached 40 N / 50 mm, the length (in mm) of the shortest part of the sample piece in the short-side direction was measured. Finally, the value (in mm) obtained by subtracting this short-side length from 50 mm was calculated and entered in the "Degree of Width Reduction" column in the table. Note that the smaller this calculated value, the better the adhesive base material can prevent width reduction.

[0074] [Table 1]

[0075] The nonwoven fabric prepared in Comparative Example 1 had a longitudinal stretch strength of less than 39.2 N / 5cm. Therefore, simply referring to the manufacturing method disclosed in Patent Document 1 (a method for manufacturing a substrate for poultice coating, which involves entangling and integrating a fiber sheet made of short fibers with longitudinally oriented fibers and a fiber aggregate made of those short fibers) does not necessarily guarantee the creation of a nonwoven fabric with a longitudinal stretch strength of 39.2 N / 5cm or higher and composed solely of cellulose fibers.

[0076] Therefore, the adhesive base material made of nonwoven fabric prepared in Comparative Example 1 had low strength and was unsuitable for use as an adhesive base material.

[0077] In contrast, the nonwoven fabric prepared in Example 1 had a strength of 39.2 N / 5 cm or more when stretched by 5% in the longitudinal direction.

[0078] Therefore, the adhesive base material made of nonwoven fabric prepared in Example 1 had high strength and was excellent for use as an adhesive base material.

[0079] (Example 2) 100% by mass of lyocell fiber A (fineness: 1.7 dt, fiber length: 38 mm), a cellulose fiber, is fed into a carding machine to open the fibers and create a unidirectional web (basis weight: 30 g / m²). 2 A crosslay web (basis weight: 70g / m²) was prepared by folding a unidirectional web prepared in the same manner so that the fiber orientations do not overlap. 2 ) was prepared. Next, a web laminate was prepared by stacking a unidirectional web and a cross-lay web. At this time, the longitudinal direction of the unidirectional web and the longitudinal direction of the cross-lay web were made parallel. A nonwoven fabric was prepared in the same manner as in Example 1, except that the web laminate prepared in this way was used.

[0080] (Example 3) 50% by mass of lyocell fiber A (fineness: 1.7dt, fiber length: 38mm), a cellulose fiber, and 50% by mass of lyocell fiber B (fineness: 1.3d, fiber length: 38mm), a cellulose fiber, are blended and then fed into a carding machine to open the fibers, resulting in a unidirectional web (basis weight: 30g / m²). 2 A crosslay web (basis weight: 70g / m²) was prepared by folding a unidirectional web prepared in the same manner so that the fiber orientations do not overlap. 2 ) was prepared. Next, a web laminate was prepared by stacking a unidirectional web and a cross-lay web. At this time, the longitudinal direction of the unidirectional web and the longitudinal direction of the cross-lay web were made parallel. The nonwoven fabric was prepared in the same manner as in Example 1, except that the web laminate prepared in this way was used.

[0081] (Example 4) Lyocell fiber A, lyocell fiber B, and the rayon fiber used in Comparative Example 1 were blended to equal mass and then fed into a carding machine to open the fibers, producing a unidirectional web (basis weight: 45g / m²). 2 A crosslay web (basis weight: 105g / m²) was prepared by folding the unidirectional web prepared in the same manner so that the fiber orientations do not overlap. 2 ) was prepared. Next, a web laminate was prepared by stacking a unidirectional web and a cross-lay web. At this time, the longitudinal direction of the unidirectional web and the longitudinal direction of the cross-lay web were made parallel. The nonwoven fabric was prepared in the same manner as in Example 1, except that the web laminate prepared in this way was used.

[0082] Table 1 summarizes the composition and properties of the nonwoven fabrics prepared in Examples 2-4. In addition, the nonwoven fabrics prepared in Examples 2-4 were used as base materials for adhesives, and their performance was evaluated.

[0083] [Table 2]

[0084] The adhesive base materials made from nonwoven fabrics prepared in Examples 2 to 4 had a strength of 39.2 N / 5cm or higher when stretched by 5% in the longitudinal direction, indicating high strength and excellent suitability for use as adhesive base materials.

[0085] Furthermore, the adhesive base material prepared in the examples exhibited minimal width reduction. This was thought to be because the nonwoven fabric constituting the adhesive base material had a fiber layer with bidirectional fiber orientation. Therefore, the adhesive base material was capable of preventing significant width reduction in the adhesive base material during various manufacturing processes for the adhesive base material and the adhesive itself. [Industrial applicability]

[0086] The adhesive base material according to the present invention can be used to provide adhesive patches (e.g., poultices, plasters, tape formulations, surgical tapes, taping materials, bandages, facial masks, warming sheets, and cooling sheets) for purposes such as providing anti-inflammatory and analgesic effects, cosmetic effects through cosmetics, or warming or cooling sensations. [Explanation of symbols]

[0087] 1. Fiber sheet 2. Fiber aggregate 3. Intertwined fiber portion

Claims

1. A base material for adhesive patches comprising a nonwoven fabric, The constituent fibers of the aforementioned nonwoven fabric consist solely of cellulosic fibers. The aforementioned nonwoven fabric has a strength of 39.2 N / 5 cm or more when stretched by 5% in the longitudinal direction. Substrate for adhesive patches.

2. The nonwoven fabric comprises a fiber layer having a bidirectional fiber orientation. The adhesive base material according to claim 1.

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