HK1145432B - Patch material - Google Patents

Description

Adhesive material

Technical Field

The present invention relates to a patch including a layer in which an adhesive layer is provided on one surface of a base material layer. In the patch of the present invention, the two layers of the base material layer and the pressure-sensitive adhesive layer constituting the patch are adhered to each other along the surface of the adherend having fine irregularities, so that the difference in surface state between the applied position and the non-applied position is small, and the applied position is inconspicuous.

The patch of the present invention, when used as a human skin patch, adheres along the skin surface having fine irregularities such as skin texture, and the patch exhibits a state in which the fine texture structure of the skin surface is transferred to the back surface (the surface of the base material layer opposite to the adhesive layer) as if so, and the position of application is inconspicuous.

The patch of the present invention is thin and stretchable, and easily follows the movement of the skin in the patch state, thereby greatly reducing the feeling of foreign matter during patch. The patch of the present invention has an appropriate adhesive force, and therefore has an excellent balance between adhesiveness to the skin surface and peelability after use.

Background

The patch is used as various patches for industrial use, stationery use, medical use, household use, and the like, and is attached to an adherend in a form suitable for each use. An adhesive material (skin adhesive material) for human skin, which has a human skin surface as an adherend, includes: medical patches represented by decorative materials for protecting skin having a damaged portion, a surgical scar, or the like; household patches such as emergency bandages, waterproof patches, and protective patches for protecting the skin. These household patches are also used in medical practice for protecting skin having a damaged part, a puncture hole of an injection needle, and the like.

The patch generally has a layer composition comprising: the adhesive layer includes a base material layer made of a plastic film, woven fabric, nonwoven fabric, knitted fabric, paper, or the like, and an adhesive layer provided on at least one surface of the base material layer. Since the patch is a foreign substance to the adherend, the patch in the state of being stuck is required to be inconspicuous in many applications. Particularly, in most of skin patches to be applied to the exposed skin surface of a human body, it is strongly required that the application position is not conspicuous.

In order to make the sticking position inconspicuous, the sticking material is preferably adhered along the skin surface having fine irregularities such as skin texture. If the patch is stuck in a state as if it were protruding without being closely adhered to the fine uneven surface of the skin, the patch is clearly different in appearance from the skin surface in the vicinity thereof, and the sticking position is noticeable. In order to make the sticking position inconspicuous, it is preferable that the patch is brought into close contact with the uneven surface of the fine texture having skin texture or the like, and the texture is transferred to the surface of the patch (the back surface of the base material layer) as if it were.

Fig. 3 is a confocal microscope image (photograph) obtained when a patch (comparative example 4 in the present specification) having a substrate layer with a thickness of more than 15 μm and a total thickness of the substrate layer and adhesive layer of more than 20 μm was attached to the skin surface of a human body. More specifically, fig. 3 shows an image obtained by forming a model on the patch in a state in which the patch is attached to the skin surface by using a impression material used for taking a dental model in dental treatment and observing the model by using a confocal microscope. The left half of fig. 3 shows the surface of the patch (the back surface of the base material layer), and the right half shows the fine texture of the skin surface of the human body. As shown in fig. 3, the patch is not in close contact with the fine uneven surface of the skin in the applied state, and is in a state of being as projected, and the state in which the fine texture structure on the skin surface is transferred to the back surface is not exhibited, so that the applied position is easily noticeable.

In the skin patch, it is an important technical problem that no foreign body sensation is felt during the patch. When the patch is not easily moved to follow the skin, a foreign body sensation is generated due to the resistance of the patch. In order to prevent the foreign body sensation during the application, the patch material must have elasticity that easily follows the movement of the skin surface having fine irregularities.

By making the entire thickness of the patch thin and using a stretchable base material, the patch can be expected to have the effect of making the patch position inconspicuous and reducing the feeling of foreign matter during application when the patch is applied to the skin surface. However, according to the results of the studies by the present inventors, it has been found that it is difficult to obtain desired results only by making the thickness of the patch thin or by using a stretchable base material.

The adhesive material is required to have appropriate adhesion. If the adhesive force of the patch is too weak, the patch is easily peeled off from the skin surface or cannot adhere to the skin surface along fine irregularities such as skin texture. When the adhesive force of the patch is too strong, inflammation occurs or peeling becomes difficult after use. When the thickness of each of the base layer, the adhesive layer, and the patch is thin, it is difficult to obtain an appropriate adhesive force.

If the base material layer constituting the patch has high rigidity and insufficient stretchability, the patch is less likely to follow the movement of the skin surface. If the thickness of the base layer or the pressure-sensitive adhesive layer is small, the stretchability of the patch can be improved, but the adhesiveness to the skin surface tends to decrease.

Therefore, it is necessary to comprehensively study the stretchability of the patch, the stretchability of the base material layer, the adhesive force of the pressure-sensitive adhesive layer, the thickness of each layer, the material of the base material layer, and the like, and to highly balance the characteristics such as the degree of visibility of the patch position, the reduction in the feeling of foreign matter during the application, and the appropriate adhesiveness.

The conventional techniques related to the patch materials do not have the above knowledge or the above knowledge is not sufficiently studied and developed. Although a patch in which the position of application is emphasized to be inconspicuous has been commercially available, the lower limit of the thickness of the base material layer of the patch is almost 20 to 30 μm. When the application position of the patch is observed, the patch has an appearance which is remarkably different from the non-application position, and the application position is not only noticeable but also hardly follows the movement of the skin when the patch is applied to the skin surface, so that a strong foreign body sensation is often generated.

JP-A-6-336425 (patent document 1) proposes an analgesic hemostatic patch in which a 5 to 350 μm thick adhesive layer containing an analgesic and a hemostatic agent is formed on one surface of a support having visible light transmittance and a thickness of 5 to 150 μm. In each example of patent document 1, there is disclosed a hemostatic analgesic patch in which an acrylic pressure-sensitive adhesive layer having a thickness of 20 μm is provided on an ethylene/vinyl acetate copolymer (EVA) film having a thickness of 60 μm; and an analgesic hemostatic patch comprising an EVA film having a thickness of 60 μm and a rubber-based adhesive layer having a thickness of 200 μm or 300 μm. The thick analgesic hemostatic plaster has a remarkable application position in an application state and has a strong foreign body sensation during application.

JP-A9-301853 (patent document 2) proposes a patch preparation in which a non-elastic layer having a thickness of 10 to 100 μm and an adhesive layer having a thickness of 1 to 15 μm are formed in this order on one surface of a support having a thickness of 0.5 to 20 μm. The patch preparation described in patent document 2 has a thick silicone-based pressure-sensitive adhesive layer or acrylic-based pressure-sensitive adhesive layer as the inelastic layer, and therefore the patch preparation attracts attention at the patch site and has a strong feeling of foreign matter during the patch application.

Japanese patent application laid-open No. Hei 7-255772 (patent document 3) discloses a skin patch substrate comprising an elastomer resin film having a thickness of 5 to 20 μm. However, patent document 3 does not specifically disclose the thickness, adhesive strength, and the like of the adhesive layer formed on the substrate. Patent document 3 also fails to provide a comprehensive study on the degree of visibility of the entire attachment site of the adhesive patch including the adhesive layer, reduction in the feeling of foreign matter when attached to the skin, and adhesion.

International publication No. 91/16044 pamphlet (patent document 4) proposes a patch comprising a film layer and an adhesive layer, wherein the film layer has a thickness of 0.5 to 4.9 μm, and is composed of a film having a strength of 8 to 85g/mm in each of 2 substantially perpendicular directions, an elongation of 30 to 150% in each of 2 substantially perpendicular directions, and a ratio of the elongations in the 2 directions of 1.0 to 5.0. The adhesive layer is laminated on one surface of the film layer, has a thickness of 2 to 60 [ mu ] m, and is composed of an adhesive containing a transdermally absorbable drug.

Patent document 4 specifically discloses a film such as a polyethylene terephthalate (PET) film that has a low elongation at break (the elongation of the film used in the examples is 120% or less) and a high glass transition temperature (the glass transition temperature of PET is 76 to 77 ℃). A resin film such as a PET film has rigidity and insufficient stretchability. Therefore, the patch material described in patent document 4 is difficult to adhere along the skin surface having fine irregularities such as skin texture, the position of application is easy to notice, and the feeling of foreign matter during application is strong. When the thickness of the PET film is 5 μm or more, skin inflammation is easily induced (page 13, right lower column of patent document 4), so that the design of the patch is greatly restricted.

JP-A-8-40910 (patent document 5) discloses a patch in which an acrylic pressure-sensitive adhesive layer having a thickness of 10 μm or more, preferably 20 μm or more and 200 μm or less is provided on a PET film having a thickness of 0.5 to 6 μm. However, since the patch is a PET film as the base material layer, even if the thickness of the base material layer is small, the patch position is easily noticed and the feeling of foreign matter during the patch application is strong, as described above.

Japanese patent application laid-open No. 2005-218496 (patent document 6) discloses a skin patch material in which an adhesive layer is formed on one surface of a base film made of an ether-based polyurethane resin having a thickness of 10 to 50 μm, preferably 25 to 35 μm. Examples of patent document 6 disclose a skin patch in which an acrylic pressure-sensitive adhesive layer having a thickness of 30 μm is formed on one surface of an ether-based polyurethane resin film having a thickness of 30 μm. However, the skin patch specifically disclosed in patent document 6 is thick and has insufficient stretchability, so that the patch position is easily noticeable and the foreign body sensation during patch cannot be sufficiently reduced.

Japanese patent No. 3868542 (patent document 7) discloses that the glass transition temperature of a base film is 25 to 35 ℃, and the moisture permeability of a laminate of the base film and an adhesive layer is 1,000g/m²Mask sheets for 24 hours or longer. However, the base film specifically disclosed in patent document 7 is rigid at room temperature, and therefore, it is difficult to adhere to the skin along the skin surface having fine irregularities such as skin texture.

The conventional adhesive material is not only difficult to adhere closely along the skin surface having a shallow and fine skin texture such as the forearm and face of the human body, but also difficult to satisfy in terms of alleviating the feeling of foreign matter during the application, because the degree of conspicuousness of the adhered position cannot be greatly reduced.

At present, in view of the degree of visibility of the position of application, the reduction of the feeling of foreign matter during application, and the like, the thickness, material, and characteristics of the base material layer constituting the patch, the thickness and adhesive force of the adhesive layer, and the thickness and characteristics of the entire patch, no comprehensive study has been made. Therefore, research and development of new attachment materials are required in this respect.

Patent document 1: japanese unexamined patent publication No. 6-336425

Patent document 2: japanese unexamined patent publication No. 9-301853

Patent document 3: japanese unexamined patent publication Hei 7-255772

Patent document 4: international publication No. 91/16044 pamphlet

Patent document 5: japanese unexamined patent publication Hei 8-40910

Patent document 6: japanese unexamined patent publication No. 2005-218496

Patent document 7: japanese patent No. 3868542

Disclosure of Invention

The invention provides a patch material which can be closely adhered along the surface of fine unevenness of an adherend, does not make the adhering position conspicuous, and is easily expanded and contracted following the movement of the adherend in the adhering state.

In particular, an object of the present invention is to provide a patch which can adhere to the skin along the surface of the skin having fine irregularities such as skin texture, does not make the position of application conspicuous, and easily follows fine movements of the skin while maintaining the attached state, and greatly reduces the feeling of foreign matter during attachment, when used as a patch for human skin.

The present inventors considered that if a patch is brought into close contact along a skin surface having fine irregularities such as skin texture and the patch is used to transfer a fine texture structure on the skin surface to a back surface, the position of attachment is not conspicuous in such a state. Further, the present inventors considered that if the base layer is formed of a thin and stretchable film and the thickness of the pressure-sensitive adhesive layer is also reduced, the patch easily follows the movement of the skin in the applied state, and therefore the feeling of foreign matter during application is greatly reduced.

However, it has been found that a patch in which a base layer is formed using a thin polyethylene terephthalate film (PET film) having a thickness of 5 μm or less and the thickness of an adhesive layer is also reduced to 5 μm cannot sufficiently adhere to the skin surface having fine irregularities such as skin texture, and the state of patch is attracting attention. Since the patch has insufficient followability to follow the movement of the skin, the patch feels a large foreign body sensation during attachment.

The present inventors have found that even when a substrate layer is formed using a film having flexibility and stretchability, it is difficult to achieve both a low visibility and a low foreign matter sensation if the stretchability in the plane direction of the patch is insufficient or the relationship between the stretchability and the thickness of the patch or the thickness of the substrate layer is not within a specific range, even when the thickness of each of the substrate layer and the pressure-sensitive adhesive layer is small, not to mention the case where the substrate layer and the pressure-sensitive adhesive layer are thick.

In order to make the patch adhere to the surface of the adherend having fine irregularities and easily follow the movement of the adherend, the patch needs to be easily expanded and contracted in the planar direction. In order to bring a flat patch into close contact with a surface of an adherend having fine irregularities, such as a skin surface, the patch must be easily stretchable in the planar direction and be capable of flexibly stretching along the fine irregularities.

Generally, if a relatively large area of a patch is to be applied to a surface of an adherend having fine irregularities, it is necessary to fix the patch to a convex portion of the surface of the adherend, and then gradually apply the patch to a concave portion along the surface of the concave portion with the convex portion as a base point. In order to adhere the adhesive material along the surface of the concave portion of the adherend, it is necessary to have the adhesive material easily spread sufficiently in the planar direction. If the adhesive material is not easily stretched in the planar direction, the adhesive material is attached in a state of being suspended in the concave portion, and therefore the attachment position is easily noticeable. Further, if the patch is not easily stretched in the planar direction, the shape of fine irregularities such as skin texture may be deformed, which is different from the appearance of the skin near the patch portion, and the patch position may be easily noticed.

The ease of extension in the surface direction of the patch can impart not only good conformability to the uneven surface but also a foreign body sensation when the patch is stuck to the skin. The surface of the skin may frequently stretch. If the adhesive material has a large stretching resistance, the feeling of resistance is felt when the skin stretches. This resistance feeling is felt as a foreign body feeling of the patch material being stuck. If the patch is easily stretched in the planar direction, the patch is easily moved to follow the skin surface, and therefore the feeling of foreign matter can be reduced.

The skin is not only subjected to stretching movement, but also retracted after stretching by the stretching amount to restore the original shape. In the case where the patch is stretched only in the plane direction and cannot be restored to its original shape, the resistance of the patch still in the stretched state is felt when the skin is retracted, so there is a feeling of foreign matter. In order to make the foreign body sensation very small in the state of being stuck to the skin, the sticking material must have good stretchability.

In view of the problems of the prior art described above, the present inventors have paid attention not only to the adhesive material, the thickness of each layer constituting the adhesive material, the stretchability of the base material layer, and the like, but also made comprehensive studies on the following aspects: (1) the thickness, material, and properties of the substrate layer, (2) the thickness and adhesion of the adhesive layer, (3) the total thickness of the substrate layer and the adhesive layer and the properties of the adhesive, and (4) the mutual relationship therebetween, and the like.

In order to achieve the above object, the present inventors have found that it is an effective approach to use an elastomer film having a very small thickness as a base layer and to reduce the thickness of a pressure-sensitive adhesive layer and the total thickness of the base layer and the pressure-sensitive adhesive layer. If the thickness of the patch is sufficiently smaller than the degree of unevenness on the surface of the adherend, the patch can be brought into close contact along the uneven surface. For example, if the thickness of the adhesive material is as thin as 5-1 or less of the depth of the concave portion on the surface of the adherend, the adhesive material can be made to adhere closely along the surface having fine irregularities.

In order to bring the adhesive material into close contact with the surface of the adherend, it is necessary to provide the adhesive layer with appropriate adhesion to the adherend. On the other hand, if the adhesive force of the adhesive layer is too large, peeling after use is difficult.

Furthermore, the present inventors have conceived that, if an adhesive material which can adhere to the surface of an adherend having a fine texture such as the surface of human skin and which can easily follow the movement of the adherend is to be obtained, it is important to make the 10% tensile load in the vertical 2 direction (longitudinal direction and lateral direction) of the adhesive material sufficiently small and to make the product of the 10% tensile load of the adhesive material and the thickness of the adhesive material and/or the product of the 10% tensile load of the adhesive material and the thickness of the base material layer fall within a specific range, in addition to making the thickness of the adhesive material and the thickness of each layer constituting the adhesive material thin.

The present invention has been completed based on these findings.

The invention provides a patch comprising a layer having a base material layer and an adhesive layer provided on one surface of the base material layer,

(a) the substrate layer is an elastomer film having a thickness of 1 to 10 μm,

(b) the thickness of the adhesive layer is in the range of 1 to 15 μm,

(c) the total thickness of the substrate layer and the adhesive layer is in the range of 2-20 μm,

(d) the 10% tensile loads in the longitudinal direction and the transverse direction of the patch measured according to JIS Z0237 are respectively in the range of 0.01-1.2N/10 mm,

(e) when the 10% tensile load value in the longitudinal direction of the patch is represented by X (N/10mm), the thickness value of the patch is represented by Y (μm), and the thickness value of the base layer is represented by Z (μm), the following relationship is satisfied: the product XY value of the 10% tensile load value X and the thickness value Y of the adhesive material is in the range of 0.02-15, or the product XZ value of the 10% tensile load value X and the thickness value Z of the base material layer is in the range of 0.01-7, and,

(f) the adhesive layer exhibits an adhesive force of 0.1N/10mm or more in a 90-degree peel test against a phenol plastic plate prescribed in Japanese Industrial Standard JIS Z0237.

The invention can provide a sticking material which has little foreign body sensation and visually feels a sticking state. In the patch of the present invention, the two layers of the base material layer and the pressure-sensitive adhesive layer constituting the patch are adhered to each other along the surface of the adherend having fine irregularities, so that the difference in surface state between the applied position and the non-applied position is small and the applied position is inconspicuous. The patch of the present invention is closely adhered along the skin surface having fine irregularities such as skin texture, and the patch is transferred to the back surface through the fine texture structure of the patch and the skin surface, and the patch position is made inconspicuous in this state.

The patch of the present invention is thin and stretchable, and easily follows the stretchable movement of the skin in the patch state, thereby greatly reducing the feeling of foreign matter during the patch. The patch of the present invention has an appropriate adhesive force, and therefore has an excellent balance between the adhesiveness to the surface of an adherend such as skin and the peelability after use.

The patch of the present invention can be used as various patches for medical use, cosmetic use, industrial use, stationery use, household use, and the like, taking advantage of these characteristics.

Drawings

Fig. 1 is a conceptual diagram showing the relationship between the thickness of the patch and the 10% tensile load.

Fig. 2 is a confocal microscope image obtained by applying the patch produced in example 4 (the thickness of the base material layer was 1 μm, and the thickness of the adhesive layer was 2 μm) to the skin surface of a human body, transferring the attached state using a dental impression material, and using the produced model. The left half of fig. 2 shows the back of the patch and the right half shows the fine structure of the skin surface.

FIG. 3 is a confocal microscope image obtained by applying the patch (the thickness of the base material layer was 18 μm, and the thickness of the adhesive layer was 7 μm) produced in comparative example 4 to the skin surface of a human body, transferring the attached state using a dental impression material, and using the produced model. The left half of fig. 3 shows the back side of the patch, and the right half shows the fine structure of the skin surface.

FIG. 4 is a graph showing the ultraviolet transmittance of the patch obtained in example 1 in a wavelength range of 280 to 400 nm.

Detailed Description

1. Layer constitution of adhesive material

The patch of the present invention has a layer structure in which an adhesive layer is provided on one surface of a base material layer. In addition to these layers, the patch material of the present invention may be provided with additional layers such as a carrier layer and a release layer. These additional layers are to be peeled off at the time of attachment. The properties of the patch of the present invention (for example, 10% tensile load, ultraviolet transmittance, and moisture permeability) are properties of a laminate composed of a base layer and an adhesive layer 2.

In most cases, a release layer is provided to protect the surface of the adhesive layer. In order to form a thin and uniform adhesive layer, it is preferable to use a method of forming an adhesive layer on a separator, not only from the viewpoint of protecting the adhesive layer.

On the other hand, many of the substrate layers are single-layer, but in the case where the thickness thereof is very thin, such as the substrate layer in the patch of the present invention, a method of forming the substrate layer on the support layer is preferably employed.

By bonding a laminate having an adhesive layer formed on one surface of a separator and a laminate having a base material layer formed on one surface of a support layer together in such a manner that the adhesive layer and the surface of the base material layer are closely bonded to each other, a laminated patch having a "support layer/base material layer/adhesive layer/separator" can be produced in which the support layer is provided on the surface of the base material layer on the side opposite to the adhesive layer and the separator is provided on the surface of the adhesive layer on the side opposite to the base material layer.

By adopting the above laminated structure, not only the patch can be easily produced, but also the usability of the patch obtained can be improved. A patch having a configuration in which a support layer and a separator are not provided, which is composed of a base material layer and an adhesive layer having a small thickness, is not strong and is likely to wrinkle, and thus is difficult to use. The adhesive material having the above laminated structure is obtained by peeling the separator to expose the adhesive layer at the time of adhesion. Even if the release layer is peeled off, the adhesive material is strong because the carrier layer is still present, and the surface of the adhesive layer can be attached to a desired attachment site. And stripping the bearing layer on the base material layer after the attachment.

2. Method for manufacturing patch

The elastomer can be formed into a film by using any molding method such as a solution casting method, an extrusion molding method, a calendering method, an inflation method, or the like. Since the base material layer of the present invention has a thickness in the range of 1 to 10 μm and is an extremely thin elastomer film, it is preferable to use a solution casting method (solution coating method) or an extrusion lamination method, and more preferably a solution casting method, in order to stably and continuously produce the film while suppressing the occurrence of cracks.

In the solution casting method, a method of coating an organic solvent solution of the elastomer on the support and drying is preferably employed. An elastomer film can be continuously produced by using a support layer as a support, applying an elastomer solution to the support layer while moving the support layer in one direction, and drying the elastomer solution. By using the solution casting method, not only the thickness of the elastomer film can be accurately controlled, but also an elastomer film having small anisotropy of physical properties in each direction can be formed.

As the Extrusion molding method, an Extrusion lamination method (Extrusion lamination) is preferred. The following methods are available as extrusion lamination methods: a method of extruding a polymer material for forming a support (carrier layer) and an elastomer from a T die together into a film shape and laminating them; a method of melt-extruding the elastomer from the T-die while moving the support (carrier layer) in one direction and laminating the elastomer on the support; and so on.

The direction of movement of the carrier layer is referred to as the longitudinal direction [ Mechanical Direction (MD) ] and the direction perpendicular to the longitudinal direction in a plane is referred to as the Transverse Direction (TD). The machine direction of the elastomeric film is determined by the direction of movement of the carrier layer or extrusion direction (MD) of the extruder. For a patch having an elastomer film as a base layer, the longitudinal direction and the transverse direction of the patch are determined according to the difference between the longitudinal direction and the transverse direction of the elastomer film.

For forming the adhesive layer, a method of coating an adhesive solution on the separator and drying is preferably employed. As a method for continuously forming the adhesive layer, a method of coating an adhesive solution on the separator while moving the separator in one direction and drying the same is preferable. A method of melting the adhesive and applying it to the release layer may also be employed.

A laminate having a laminate of "support layer/base layer/adhesive layer/separator" can be produced by separately producing a laminate having an adhesive layer formed on one surface of a separator and a laminate having a base layer formed on one surface of a support layer, and then bonding these laminates together so that the adhesive layer and the base layer are in close contact with each other.

When the patch is attached to the skin surface of a human body, it is sometimes preferable to form fine irregularities on the back surface of the base material layer constituting the patch (the surface of the base material layer opposite to the pressure-sensitive adhesive layer) in order to improve the feel, smoothness, appearance, and the like of the patch. In this case, the fine irregularities may be formed by embossing the surface of the support layer, and the substrate layer may be formed on the fine irregularities, thereby transferring the fine irregularities to the surface (back surface) of the substrate layer made of the elastomer film.

3. Substrate layer

In the present invention, an elastomer film having a thickness in the range of 1 to 10 μm is used as a base material layer.

As the elastomer for forming the elastomer film, an elastomer having excellent stretchability satisfying the following conditions can be used: (1) a thin film having a thickness in the range of 1 to 10 μm can be formed; (2) when the adhesive material is used as a base material layer of the adhesive material, the adhesive material with the longitudinal and transverse 10% tensile loads respectively in the range of 0.01-1.2N/cm can be manufactured; and (3) when the adhesive material is used as a base material layer of the adhesive material, the XY value and/or the XZ value of the adhesive material satisfies a specific range. Since the pressure-sensitive adhesive layer is thin, the 10% tensile load value of the patch is substantially the same as the 10% tensile load value of the elastomer film constituting the base layer.

Examples of the elastomer include polyurethane elastomers, 1, 2-polybutadiene thermoplastic elastomers, polystyrene thermoplastic elastomers, polyolefin thermoplastic elastomers, and mixtures of 2 or more of these.

Among these elastomers, polyurethane elastomers are preferable because of excellent film-forming properties of the film, excellent stretchability of the film, and easy control of the 10% tensile load value, XY value, and XZ value of the film within desired ranges.

The polyurethane elastomer is an elastomer having a urethane group in a molecule, and is produced by an addition polymerization reaction of a polyol component and an isocyanate component. As the polyol component, a polyol compound having 2 or more hydroxyl groups may be used, but a long-chain diol is used in most cases. In addition, short-chain diols that function as chain extenders may be used in combination as the polyol component. In addition, a monomolecular polyol such as trimethylolpropane, glycerin, or sorbitol may be used as a crosslinking agent. As the isocyanate component, a polyisocyanate compound having 2 or more NCO groups can be used, but a diisocyanate is used in most cases. The manufacturing techniques for polyurethane elastomers are well known in the art.

The polyurethane elastomer includes, but is not particularly limited to, thermoplastic polyurethane elastomers, thermosetting polyurethane elastomers (amine-curable polyurethane elastomers and hydroxyl-curable polyurethane elastomers), and the like. The thermoplastic elastomer includes a complete thermoplastic polyurethane elastomer having almost no NCO groups and an incomplete thermoplastic polyurethane elastomer having a considerable amount of NCO groups remaining therein and causing partial intermolecular crosslinking during molding, and any of them can be used in the present invention. The heat-curable polyurethane elastomer includes a 1-liquid curable type and a 2-liquid curable type, and any of them can be used, but the 1-liquid curable type is preferable in terms of ease of film formation.

There are various methods for classifying the polyurethane elastomer, but since the kind of the polyol component constituting the soft segment greatly affects the properties of the polyurethane elastomer, it is convenient to classify the polyurethane elastomer according to the kind of the polyol component.

More specifically, the polyurethane elastomer includes: (1) the caprolactone type polyurethane elastomer is synthesized by carrying out addition polymerization reaction on polylactone polyol obtained by caprolactone ring-opening polymerization and diisocyanate compound; (2) adipate polyurethane elastomer synthesized by addition polymerization of adipate polyol formed by adipic acid and diol compound and diisocyanate compound; and (3) a polyether polyol such as poly-1, 4-butanediol obtained by ring-opening polymerization of tetrahydrofuran or polyalkylene glycol such as polypropylene glycol, and a diisocyanate compound. Polyols having 3 or more hydroxyl groups and/or polyisocyanate compounds having 3 or more NCO groups can also be used in these polyurethane elastomers.

Polyurethane elastomers can be classified into polyether type and polyester type according to the structure of the main chain. Examples of the polyether urethane elastomer include those described above. The polyester polyurethane elastomer includes the caprolactone polyurethane elastomer and the adipate polyurethane elastomer. However, the polyurethane elastomer used in the present invention is not limited to the main chain structure, and other types of polyurethane elastomers may be used.

Examples of the polyurethane elastomer suitable for the present invention include ラツクスキン US2268 (polyether type) available from the company of セイコ; ラツクスキン U-1223, U-1285, and U-2860 (polyester type), but not limited thereto. These polyurethane elastomers may be used alone, respectively, or in combination of 2 or more.

The glass transition temperature (Tg) of the elastomer is not particularly limited. For example, the glass transition temperature of highly elastic polyurethane elastomers is sometimes as high as 50 ℃. The glass transition temperature of the elastomer is preferably in the range of-70 to 20 ℃ from the viewpoints of the stretchability, flexibility, 10% tensile load, and the like of the elastomer film. The upper limit of the glass transition temperature is preferably 20 ℃, more preferably 10 ℃, and particularly preferably 0 ℃. The lower limit of the glass transition temperature is usually-60 ℃ or-55 ℃. The glass transition temperature of the elastomer is a value measured according to a usual method using a differential scanning calorimeter.

The base material layer is an elastomer film with the thickness of 1-10 mu m. In the elastomer film, it is preferable that the difference in the direction of physical properties (anisotropy) is small in order to reduce the feeling of foreign matter during application (the feeling of resistance of the patch felt when the skin stretches). As the film forming method, a solution casting method is preferably used because a thin elastomer film having substantially the same physical properties such as 10% tensile load in the longitudinal direction and the transverse direction can be obtained.

The thickness of the elastomer film constituting the substrate layer is 1 to 10 μm, preferably 1 to 9 μm, and more preferably 1 to 8 μm. The thickness of the elastomer film can be reduced to a thickness within the range of 1 to 5 μm in order to make the adhesive material inconspicuous during the application and reduce the foreign body sensation.

When the thickness of the elastomer film is less than 1 μm, not only film formation is difficult, but also the strength as the base layer is insufficient, and the base layer may break when the patch is attached to the adherend or the patch is peeled from the adherend. If the thickness of the elastomer film is too large, even if the thickness of the entire patch is reduced, it is difficult to bring the patch into close contact with the skin surface having fine irregularities such as skin texture, and the patch state tends to be noticeable, resulting in an increased feeling of foreign matter.

In order to control the 10% tensile load of the patch in the longitudinal direction and the transverse direction within the range of 0.01 to 1.2N/10mm, an elastomer film having 10% tensile load of the patch in the longitudinal direction and the transverse direction within the range of 0.01 to 1.2N/10mm is used as a base material layer.

The elastomer film has 10% tensile loads in the longitudinal direction and the transverse direction, respectively, of 0.01 to 1.2N/10mm, preferably 0.03 to 1.1N/10mm, more preferably 0.05 to 1.0N/10mm, and particularly preferably 0.06 to 0.95N/10mm, as measured according to JIS Z0237.

In the case of an elastomer film having small anisotropy of physical properties in each direction, such as a film obtained by a solution casting method, the value of 10% tensile load in the machine direction is substantially the same as the value of 10% tensile load in the transverse direction. Even when other film forming methods are used, the 10% tensile load value of the elastomer film does not greatly differ between the longitudinal direction and the transverse direction.

If the 10% tensile load of the elastomer film is too small, the thickness is generally too small, and the film formability and the usability are deteriorated. If the 10% tensile load of the elastomer film is too large, the rigidity is increased, and the stretchability and flexibility are insufficient, so that it is difficult to bring the patch using the elastomer film as a base material layer into close contact with the skin surface having fine irregularities such as skin texture, and the patch state is easily noticeable. And when a patch in which an elastomer film having an excessive tensile load of 10% is used as a base material layer is attached to the skin surface, the feeling of foreign matter becomes large.

The 10% tensile load in the machine direction and transverse direction of a polyethylene terephthalate (PET) film becomes large, respectively, to 3.0N/10mm if it is in the case where the thickness thereof is as thin as 1.5 μm. Therefore, it is difficult to adhere a patch using a PET film as a base layer along a skin surface having fine irregularities such as skin texture, and the adhesion state is easily noticeable. And when a patch having a PET film as a base material layer is attached to the skin surface, the feeling of foreign matter is large.

The elongation at break in the Machine Direction (MD) of the elastomer film used in the present invention is preferably 130 to 1,000%, more preferably 135 to 800%, and particularly preferably 140 to 500%. Since the anisotropy of the elongation at break of the elastomer film due to the direction difference is small, the elongation at break in the Transverse Direction (TD) shows a value of substantially the same level as the elongation at break in the longitudinal direction.

If the elongation at break of the elastomer film is too small, the rigidity is increased and the stretchability is insufficient. Therefore, a patch using an elastomer film having an excessively low elongation at break as a base material layer is difficult to adhere along a skin surface having fine irregularities such as skin texture, the patch position is easily noticed, and the feeling of foreign matter at the time of patch is enhanced. If the elongation at break of the elastomer film is too large, the stretchability may be insufficient.

The elastomer film constituting the base layer may contain a colorant such as a pigment or a dye as necessary. The elastomer film may contain various additives such as a stabilizer, an ultraviolet absorber, a smoothing agent, and the like as needed.

4. Adhesive layer

The adhesive layer may be formed using an adhesive that exhibits pressure-sensitive adhesiveness at normal temperature. In order to use the patch of the present invention as a skin patch, an adhesive agent having little irritation to the skin is preferably used. Examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesives, natural rubber pressure-sensitive adhesives, synthetic rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives, vinyl ester pressure-sensitive adhesives, vinyl ether pressure-sensitive adhesives, and polyurethane pressure-sensitive adhesives, and among them, pressure-sensitive adhesives of the grade of medical pressure-sensitive adhesives are preferably used.

Among the pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferred in view of their low skin irritation, easy control of pressure-sensitive adhesive properties, excellent weather resistance, and the like, and stable quality. The acrylic pressure-sensitive adhesive is preferably a copolymer obtained by using an alkyl acrylate or an alkyl methacrylate which is an esterified product of an aliphatic alcohol having 1 to 18 carbon atoms and acrylic acid or methacrylic acid. Specifically, the acrylic pressure-sensitive adhesive is preferably a copolymer of at least one acrylic monomer selected from alkyl acrylates and alkyl methacrylates each having an alkyl group having 1 to 18 carbon atoms and another monomer copolymerizable with the acrylic monomer.

The acrylic adhesive is more preferably a copolymer of the following components: 60 to 95 wt% of alkyl acrylate having an alkyl group with 4 to 18 carbon atoms; 1 to 25% by weight of a vinyl monomer having at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride group, an amide group, an amino group, an epoxy group, and an alkoxy group; and 0 to 40% by weight of another vinyl monomer copolymerizable with the alkyl acrylate. The alkyl acrylate particularly preferably has an alkyl group having 8 to 12 carbon atoms.

When the alkyl acrylate and/or the alkyl methacrylate is referred to as "alkyl (meth) acrylate", examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate. These alkyl (meth) acrylates may be used singly or in combination of 2 or more kinds.

Among these alkyl (meth) acrylates, alkyl acrylates having 4 to 18 carbon atoms, preferably 8 to 12 carbon atoms such as 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, isononyl acrylate, and the like are preferable.

Examples of the vinyl monomer having a functional group include acrylic esters having a hydroxyl group such as 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate; vinyl monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, and monobutyl maleate; vinyl monomers having an amide group such as acrylamide, dimethylacrylamide, diethylacrylamide, methacrylamide, and N-methylolacrylamide; vinyl monomers having an amino group such as dimethylaminoethyl acrylate; vinyl monomers having an epoxy group such as glycidyl acrylate and glycidyl methacrylate; vinyl monomers having a pyrrolidone ring such as N-vinylpyrrolidone; alkoxyalkyl acrylates such as 2-methoxyethyl acrylate and ethoxyethyl acrylate; and so on. These monomers having a functional group may be used alone or in combination of 2 or more.

Examples of the other vinyl monomer copolymerizable with the alkyl acrylate include vinyl esters such as vinyl acetate; unsaturated nitriles such as acrylonitrile and methacrylonitrile; vinyl aromatic compounds such as styrene; and so on.

When an alkyl acrylate having 4 to 18 carbon atoms, preferably 8 to 12 carbon atoms is used as the alkyl acrylate, another alkyl (meth) acrylate may be used as another vinyl monomer copolymerizable with the alkyl acrylate. Examples of the other alkyl (meth) acrylates include alkyl acrylates such as methyl acrylate and ethyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, isononyl methacrylate, n-decyl methacrylate, isodecyl methacrylate, lauryl methacrylate and stearyl methacrylate; and so on.

Other vinyl monomers copolymerizable with the alkyl acrylate may be used alone or in combination of 2 or more, respectively.

The acrylic adhesive is preferably a copolymer of the following components: 60 to 95 wt%, preferably 65 to 95 wt%, more preferably 70 to 90 wt% of an alkyl acrylate having an alkyl group with 4 to 18 carbon atoms, preferably 8 to 12 carbon atoms; 1 to 25 wt%, preferably 1 to 20 wt%, more preferably 2 to 15 wt% of a vinyl monomer having a functional group; and 0 to 40 wt%, preferably 0 to 30 wt%, more preferably 0 to 25 wt% of another vinyl monomer copolymerizable with the alkyl acrylate. By using an acrylic pressure-sensitive adhesive having such a copolymer composition, a pressure-sensitive adhesive layer exhibiting appropriate pressure-sensitive adhesive properties and excellent in other properties can be easily formed even with a thin pressure-sensitive adhesive layer.

The weight average molecular weight of the acrylic adhesive is preferably 300,000 to 1,000,000, more preferably 450,000 to 650,000. When the weight average molecular weight of the acrylic pressure-sensitive adhesive is within the above range, the cohesion, the adhesive force, the workability of mixing with other components, the affinity with other components, and the like can be balanced. The weight average molecular weight of the acrylic pressure-sensitive adhesive is a value determined as a standard polystyrene equivalent value by a Gel Permeation Chromatography (GPC) method.

Acrylate copolymers can generally be synthesized by free radical polymerization. The polymerization method includes a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and the like, and the solution polymerization method is preferable in terms of easily obtaining good adhesive properties. Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide and lauroyl peroxide; azo initiators such as azobisisobutyronitrile; and so on. A radical polymerization initiator is added to all monomers in an amount of about 0.1 to 3 wt%, and the mixture is stirred at a temperature of about 40 to 90 ℃ for several to several tens of hours under a nitrogen stream to copolymerize the monomers. In the solution polymerization method, ethyl acetate, acetone, toluene, a mixture thereof, and the like are commonly used as a solvent.

The thickness of the adhesive layer is 1 to 15 μm, preferably 1 to 12 μm, more preferably 2 to 10 μm, and particularly preferably 2 to 9 μm. In many cases, a thickness of the adhesive layer is 2 to 8 μm, and further, a thickness of the adhesive layer is in the range of 2 to 7 μm, and thus, good results can be obtained.

In general, the pressure-sensitive adhesive layer has a smaller tensile resistance and a higher stretchability than the base material layer, and therefore the effects of the present invention can be obtained in a wider range than the thickness of the base material layer. However, if the thickness of the pressure-sensitive adhesive layer is too large, it may be difficult to adhere the patch to the skin along the surface of the skin having fine irregularities such as skin texture, and if the adhesive strength is too high, it may be difficult to peel the patch after use. If the thickness of the pressure-sensitive adhesive layer is too thin, it is difficult to obtain an appropriate adhesive force and to adhere the patch to the surface of the adherend having fine irregularities such as skin.

The adhesive force of the adhesive layer is preferably set to be high in order to make the thickness of the adhesive layer thin, but is more preferably set within an appropriate range in terms of a high balance between adhesiveness to the surface of an adherend such as skin and ease of peeling (peelability) after use.

In a 90-degree peel test against a phenol resin plate prescribed in Japanese Industrial Standard JIS Z0237, the adhesive layer is required to exhibit an adhesive force of 0.1N/10mm or more. The adhesive force is preferably 0.1 to 3N/10mm, more preferably 0.15 to 2N/10mm, and particularly preferably in the range of 0.15 to 1N/10 mm. If the adhesive force of the adhesive layer is too low, the adhesive layer is likely to peel off by an external force such as skin movement when attached to an object such as skin. If the adhesive force of the adhesive layer is too strong, it is difficult to peel off from the adherend surface after use.

Although the lower limit value of 0.1N/10mm of the adhesive force of the adhesive layer is a very small value compared to the adhesive force of conventional adhesive materials, since the base material layer is thin and flexible, if the thickness of the base material layer and the 10% tensile load value satisfy appropriate ranges, it can be determined that the adhesive property as an adhesive material is sufficient.

The adhesive layer may contain various additives as needed. As an additive, for example, in the case of a skin patch, a drug that can be absorbed through the skin may be contained. Examples of the drug include an angina pectoris agent, a corticosteroid agent, an analgesic and anti-inflammatory agent, an antihistamine, an antibacterial agent, a moisturizer, vitamins, and a perfume. The adhesive layer may contain various colorants such as pigments and dyes.

5. Thickness of the adhesive material

The thickness of the elastomer film constituting the base material layer of the patch of the present invention is 1 to 10 μm, preferably 1 to 9 μm, and more preferably 1 to 8 μm. The thickness of the adhesive layer is 1 to 15 μm, preferably 1 to 12 μm, more preferably 2 to 10 μm, and particularly preferably 2 to 9 μm.

The total thickness of the base material layer and the adhesive layer (sometimes simply referred to as the thickness of the patch) is within a range of 2 to 20 [ mu ] m. The total thickness of the base material layer and the adhesive layer is preferably 2-15 μm, and more preferably 3-14 μm. In many cases, good results are obtained when the total thickness of the base layer and the adhesive layer is in a very thin range of 3 to 10 μm or 3 to 7 μm.

When the total thickness of the substrate layer and the pressure-sensitive adhesive layer is too thin, the adhesive force is low, and the production is difficult. When the total thickness of the base layer and the pressure-sensitive adhesive layer is too large, the patch in a stuck state tends to be noticeable, and the feeling of foreign matter may be increased.

The thickness of each layer in the present invention was measured using a dial gauge.

6. 10% tensile load of the patch

The 10% tensile load in the longitudinal direction and the 10% tensile load in the transverse direction of the patch of the present invention are required to be in the range of 0.01 to 1.2N/10mm, respectively. Here, the patch refers to a laminate (base layer/adhesive layer) composed of 2 layers of a base layer and an adhesive layer, and means a material from which the support layer and the separator layer are removed.

The patch of the present invention, particularly when used as a skin patch, can adhere to the skin along the surface of the skin having fine irregularities such as skin texture and can easily follow the movement of the skin. This characteristic is related to the degree of stretchability of the patch material. In the present invention, a 10% tensile load value is used as an index for indicating the degree of stretchability of the patch in consideration of daily skin stretching.

When the 10% tensile load in the longitudinal direction and the lateral direction of the patch is in the range of 0.01 to 1.2N/10mm, respectively, when the patch is applied to the skin of a human body, the patch is stretched in the planar direction during application, and is likely to adhere to the skin along the skin surface having fine irregularities such as skin texture, and to follow the daily movement of the skin.

The 10% tensile load of the patch was a value measured in accordance with JIS Z0237. The 10% tensile load of the patch is 0.01 to 1.2N/10mm, preferably 0.03 to 1.1N/10mm, more preferably 0.05 to 1.0N/10mm, and particularly preferably 0.06 to 0.95N/10mm in both the longitudinal and transverse directions.

When the 10% tensile load of the patch is too small, the thickness of the elastomer film as the base layer is generally too small, and the film formability and the usability are low. When the 10% tensile load of the patch is too large, the rigidity becomes large, the stretchability and flexibility are insufficient, it is difficult to closely adhere the patch along the skin surface having fine irregularities such as skin texture, and the adhesion state is noticeable. When the adhesive material having an excessive 10% tensile load was applied to the skin surface, the feeling of foreign matter was enhanced.

In the patch of the present invention, it is preferable that the 10% tensile load values in the longitudinal direction and the lateral direction are substantially the same from the viewpoint of making the patch inconspicuous in the applied state and reducing the foreign substance sensation.

Relationship between 7.10% tensile load and thickness of the patch or substrate layer

In the patch of the present invention, when the value of 10% tensile load in the Machine Direction (MD) is denoted by X (N/10mm), the value of thickness of the patch is denoted by Y (μm), and the value of thickness of the base layer is denoted by Z (μm), the following relationship is required: the XY value of the product of the 10% tensile load value X and the thickness value Y of the adhesive material is in the range of 0.02-15, or the XZ value of the product of the 10% tensile load value X and the thickness value Z of the base material layer is in the range of 0.01-7. Here, the adhesive material means a 2-layer laminated body composed of a base material layer and an adhesive layer.

The present inventors have found that, in order to make the patch material in a stuck state inconspicuous and reduce the foreign substance sensation, it is insufficient to control only the material and thickness of the base material layer, the thickness and adhesive strength of the adhesive layer, the total thickness of the base material layer and the adhesive layer, and the 10% tensile load of the patch material within specific ranges.

As a result of further studies, it was found that both unnoticeable appearance of the patch and reduction in the foreign substance sensation can be sufficiently achieved by controlling the XY value, which is the product of the 10% tensile load value X in the longitudinal direction of the patch and the thickness value Y of the patch, and/or the XZ value, which is the product of the 10% tensile load value X in the longitudinal direction of the patch and the thickness value Z of the base layer, to be within specific ranges. Since the 10% tensile load value of the patch is not substantially different between the longitudinal direction and the transverse direction, the 10% tensile load value in the longitudinal direction is used in the present invention.

If the 10% tensile load value of the patch is small, when the thickness of the patch or the thickness of the base material layer is large, it is difficult to bring the patch into close contact with the skin surface having fine irregularities such as skin texture, and it is difficult to bring a state in which the fine texture structure on the skin surface is transferred to the back surface by the patch. As a result, the adhesive material in the adhered state is noticeable.

If the thickness of the patch or the thickness of the base material layer is small, when the 10% tensile load value of the patch is large, it is difficult to bring the patch into close contact with the skin surface having fine irregularities such as skin texture, and it is difficult to transfer the fine texture structure of the skin surface to the back surface by the patch. As a result, the adhesive material in the adhered state is noticeable.

When the XY value and/or the XZ value is too large, the patch in a stuck state tends to be noticeable and the foreign substance sensation tends to be increased.

The present inventors studied the relationship between the 10% tensile load value of the base material layer, the thickness of the patch, the thickness of the base material layer, the visibility of the patch and the feeling of foreign matter, and examined experimental data, and found that when the product XY of the 10% tensile load value X of the patch and the thickness value Y of the patch is in the range of 0.02 to 15 and/or the product XZ of the 10% tensile load value X of the patch and the thickness value Z of the base material layer is in the range of 0.01 to 7, the product XY affects the requirements of the thickness of each layer, the adhesive strength, and the like, and a high balance between the visibility of the patch and the feeling of foreign matter can be obtained.

Fig. 1 shows a conceptual diagram of a region expressed by a product XY value of a 10% tensile load value X of an attached material and a thickness value Y of the attached material. The patch of the present invention falls within a rectangle shown in fig. 1, which shows upper and lower limits of the thickness of the patch, and upper and lower limits of the 10% tensile load. However, after the test data was arranged, it was found that even if the patch falls within the range of the rectangle shown in fig. 1, there was a region where the inconspicuous property of the patch and the reduction of the foreign substance sensation could not be sufficiently achieved. This region is the region shown as B in fig. 1.

The patch of the present invention is located in a region a (X is 0.01 to 1.2N/10mm, Y is 2 to 20 μm, and XY is 0.02 to 15) in the rectangular region shown in fig. 1. The relationship between the 10% tensile load value X of the patch and the thickness Z of the base material layer is similar to that in fig. 1. The 10% tensile load of the patch is greatly affected by the base material layer, and substantially coincides with the 10% tensile load value of the base material layer. Here, for example, in the case where the thickness of the adhesive layer is fixed to change the thickness of the base material layer, and in the case where the thickness of the base material layer is fixed to change the thickness of the adhesive layer, the 10% tensile load value change in the former case is small, and therefore, the region a of the patch has a laterally longer shape than the region determined by the thickness of the base material layer.

The product XY of the 10% tensile load X (N/10mm) in the longitudinal direction of the patch of the present invention and the thickness Y (μm) of the patch is 0.02 to 15, preferably 0.1 to 12, and more preferably 0.3 to 11.

The patch of the present invention has an XZ value, which is a product of a 10% tensile load X (N/10mm) in the longitudinal direction and the thickness Z (μm) of the base material layer, of 0.01 to 7, preferably 0.05 to 6.8, and more preferably 0.08 to 6.5.

When the XY value and/or the XZ value is too large, the patch in a stuck state tends to be noticeable and the foreign substance sensation tends to be increased in many cases. When the XY value and/or XZ value is too small, other characteristics such as adhesion are low, and the production is difficult.

8. Skin feel of adhesive material

The skin feel of the surface of the patch of the present invention (the back surface of the base material layer) can be judged by the smoothness of the surface. In order to improve the smoothness of the surface of the patch, it is preferable to provide fine irregularities on the back surface of the base material layer. For this purpose, it is preferable to form fine irregularities on the back surface of the base layer by finely embossing the base layer and then forming the base layer on the base layer.

Smoothness can be quantified by the coefficient of kinetic friction. The coefficient of dynamic friction can be measured by the following method, with partial modification to the horizontal method specified in JIS P8147.

The maximum load of the load chamber of the constant-speed extension tensile tester was set to 10N, and the position of the forearm as flat as possible was used without using a horizontal plate. The weight was a 20mm x 20mm brass cube. The patch of the present invention is attached to one surface of the weight so as not to cause a scratch, a wrinkle, or the like, and the attached surface is placed on the forearm, and a hook attached to the weight via a thin wire is pulled. A carriage is fixed to a hanging portion of the load chamber in advance, and the weight is horizontally moved by positioning the carriage just above the arm. The moving speed of the weight was set to 100mm per minute and the moving distance of the weight was set to 50mm, and the frictional force therebetween was recorded. The frictional force displayed when the weight is moved is taken as a kinetic frictional force. The dynamic friction coefficient was determined as the value obtained by dividing the obtained average dynamic friction force by the vertical load applied by the weight.

When the coefficient of dynamic friction measured by the above method is 1.0 or less, the feeling of foreign matter is lost in the smoothness of the surface of the patch with respect to the skin. When the surface of the patch is embossed to have a coefficient of kinetic friction of 1.0 or less, the surface of the patch is suitably reduced in gloss and is inconspicuous in appearance. The lower limit value of the coefficient of dynamic friction is usually 0.1.

9. Other characteristics of the adhesive material

The patch of the present invention has an ultraviolet transmittance of preferably 25% or less, more preferably 15% or less, and still more preferably 10% or less at a wavelength of 280 to 400 nm. The patch herein means a laminate formed of a base layer and an adhesive layer 2.

Depending on the application of the patch, there may be a problem in the ultraviolet transmittance. The patch of the present invention is sometimes used as a medical patch, and it is sometimes desired to protect a damaged portion from ultraviolet rays. The patch of the present invention can exhibit good ultraviolet-blocking properties even if it does not contain an ultraviolet absorber. In order to further reduce the ultraviolet transmittance of the patch of the present invention, a method of containing an ultraviolet absorber in the base layer and/or the adhesive phase may be employed.

Depending on the use of the patch, it may be preferable to color the base layer and/or the adhesive layer. The skin patch may be colored, for example, in the color of the skin so as to make the attached state inconspicuous. Various colorants such as pigments, dyes, inks, and the like can be used for coloring.

The patch of the present invention has a moisture permeability of 1,000g/m²24 hours or longer, preferably 2,000g/m²24 hours or longer, more preferably 2,500g/m²24 hours or longer, particularly preferably 3,000g/m²24 hours or longer. The upper limit value of the moisture permeability of the patch is usually 10,000g/m²24 hours, in many cases 5,000g/m²24 hours. The moisture permeability is a value measured under condition B (temperature 40 ℃ C., relative humidity 90%) defined in JIS Z0208. Since the patch has a high moisture permeability, it is possible to prevent the patch from becoming stuffy or accumulating sweat during patch application.

10. Bearing layer

Since the patch of the present invention is extremely thin and has good stretchability, it is difficult to form a base layer without a carrier layer, and the usability is reduced. When the patch of the present invention has no carrier layer, it is sometimes difficult to satisfactorily attach the patch to an adherend, wrinkles on the base material layer, or the adhesive layers adhere to each other. By temporarily disposing the base material layer on the support layer, the film forming property of the base material layer, the usability of the patch, and the adhesion property to the adherend can be improved. The support layer is provided for improving the usability of the patch, and may be coated on the entire surface of the patch, only on the edge of the patch, or in a lattice pattern.

The support layer is preferably formed using a film made of various thermoplastic resins such as polyurethane, polyethylene, polypropylene, ionomer, polyamide, polyvinyl chloride, poly-1, 1-dichloroethylene, ethylene/vinyl acetate copolymer, thermoplastic polyester, polytetrafluoroethylene, and the like.

For environmental protection, the carrier layer may be formed of various biodegradable plastics such as polyhydroxybutyrate, polyhydroxybutyrate resins, polyhydroxyalkanoates, maltotriose, polylactic acid-based resins, polyethylene succinate resins, polybutylene succinate resins, polycaprolactone resins, polybutylene adipate terephthalate, 1, 4-butylene adipate terephthalate, polyethylene terephthalate resins, polyvinyl alcohol, polyglycolic acid, starch fatty acid esters, starch processing resins, starch polyesters, cellulose acetate, chitosan, and the like.

The various films may be laminated on paper. Preferably, these bearing layers are thicker and stronger than the polyurethane elastomer layer thickness. The thickness of the carrier can be set as appropriate, but is usually 10 μm or more, preferably 20 μm or more, and its upper limit value is about 500 μm.

Since the elastomer film of the base material layer and the adhesive layer are firmly bonded together, the support layer is easily peeled off in use.

11. Insulating layer

The adhesive material is preferably provided with a release layer immediately before the application in order to protect the adhesive layer. As the separator, what is generally called release paper, release film, release liner, or the like in the field of tape technology can be used. As the separator, for example, a polyethylene terephthalate film whose surface is treated with silicone, a laminate of polyethylene and paper whose surface is treated with silicone, and the like are typically given.

Examples

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

The measurement method and the evaluation method in the present invention are as follows.

(1) 10% tensile load

The 10% tensile load of the patch was measured in accordance with JIS Z0237. Specifically, the patch was stretched by 10% using an instron type tensile tester, and the load (N) at this time was measured. The obtained value was converted into a width of 10 mm. The measurement is performed in both the longitudinal and transverse directions, but since the values are substantially the same, the longitudinal measurement value is used. The 10% tensile load of the substrate layer was determined using the same method.

(2) Evaluation of degree of conspicuousness

The test piece was cut into 17mm × 29mm pieces and evaluated for visibility when attached to human skin. The test piece was attached to the back and forearm of 5 adult men and women. The attached state was visually evaluated, and the state attached to the skin surface was transferred using a dental impression material, and the resulting model was used to evaluate an image of a confocal microscope thereof. The evaluation criteria are as follows.

AA: 4-5 people are not obvious.

A: 3 people are not obvious.

B: 2 people are not obvious.

C: 1 person or no person is inconspicuous.

(3) Evaluation of foreign body sensation

The 5 persons who performed the test (2) were asked to listen to the evaluation of the foreign body sensation, and the evaluation was performed according to the following criteria.

AA: 4-5 people have no foreign body sensation.

A: 3 people have no foreign body sensation.

B: 2 people have no foreign body sensation.

C: no foreign body sensation was felt by 1 person or no person.

(4) Evaluation of adhesion

The adhesive force (peel force) was measured by a 90-degree peel test of the adhesive material from a phenol plastic plate as defined in JIS Z0237. Specifically, a patch having a width of 10mm was stuck on a phenol plastic plate, and the adhesive force (N) when the patch was pulled in a direction of 90 degrees was measured by using an Instron type tensile tester. Based on the measured value of the adhesive force, the adhesion was evaluated according to the following criteria. This adhesion is considered to be consistent with the evaluation of skin adhesion.

A: the adhesive force is more than 0.1N/10mm,

c: the adhesive force is less than 0.1N/10 mm.

(5) Elongation at break

The elongation at break of the elastomeric film was measured using the following method. The elastomeric film was cut to a width of 20mm in the Machine Direction (MD) and then cut to a length of about 75mm to make test pieces. The test piece was mounted on an Instron type tensile tester (10N and 100N load cell) with a grip set at 50 mm. The test piece was pulled at a moving speed of 300 mm/min. The elongation at break of the test piece was read and the elongation at break (%) was calculated.

(6) Degree of easiness of peeling

The patch was cut into test pieces of 17mm × 29mm in size, and attached to the backs and forearm parts of 5 adult men and women. After 30 minutes, the test piece was peeled from the attached portion. The ease of peeling was evaluated according to the following criteria.

AA: and is easily peeled off from the end portion.

A: it is difficult to grasp the end for peeling.

B: not only is it difficult to grasp the end for peeling, but sometimes the attached material is broken in peeling.

(7) Moisture permeability

The moisture permeability of the patch was measured under condition B (temperature 40 ℃ C., relative humidity 90%) defined in JIS Z0208.

(8) Coefficient of dynamic friction

The coefficient of dynamic friction was measured using the above method partially modified by the horizontal method specified in japanese industrial standard JIS P8147. The human subject to be tested for the kinetic friction coefficient was 10 adult male and female.

[ example 1]

An organic solvent solution of an acrylic adhesive (copolymer of 2-ethylhexyl acrylate/vinyl acetate/acrylic acid in 85/11/4 weight ratio) was coated on one side of a release layer (release paper) using a bar coating method so that the thickness after drying was 5 μm, and then dried to form an adhesive layer.

A high-quality paper (high quality paper) laminated with polyethylene was used as a support layer, and an ether-type moisture-permeable polyurethane elastomer solution was applied to the polyethylene-side surface thereof by a bar coating method so that the thickness after drying was 5 μm, followed by drying to form a base layer. The ether polyurethane elastomer solution was セイコ -mer under the trade designation "ラツクスキン US 2268" (Tg ═ 23.1 ℃).

The obtained base material layer and the adhesive layer were bonded together to produce a laminate comprising a carrier layer/base material layer/adhesive layer/separator. The adhesive material can be used for peeling off the isolation layer and peeling off the bearing layer after being attached on the skin. The patch in the attached state adheres closely along the skin surface containing fine irregularities such as skin texture, and has no foreign body sensation.

In the patch, the thickness Y of the patch was 10 μm, the thickness of the base material layer was 5 μm, the elongation at break of the base material layer was 356%, the thickness of the adhesive layer was 5 μm, the 10% tensile load in the longitudinal and transverse directions was 0.15N/10mm, the XY value was 1.50, the XZ value was 0.75, the adhesive force of the adhesive layer was 0.59N/10mm, and the moisture permeability was 3,280g/m²24 hours.

Therefore, the patch is inconspicuous in a patch state, free from foreign body sensation, excellent in adhesion, and sufficient in air permeability.

The ultraviolet transmittance of the adhesive material in the wavelength range of 280 to 400nm is shown in FIG. 4.

[ example 2]

The polyurethane elastomer solution used in example 1 was applied onto the polyethylene-side surface of a high-quality paper embossed on the polyethylene surface as a support layer by a bar coating method so that the thickness after drying was 5 μm in the same manner as in example 1, and dried to form a base layer, and then the base layer and an adhesive layer were bonded to each other to prepare a patch.

This attached material, through the embossing shape that gives on the polyethylene side surface of carrier layer, has retransferred the embossing shape on the surface of substrate layer, and when pasting attached material on skin, this embossing shape makes attached material more inconspicuous. The embossed shape eliminates the foreign body sensation of the skin and the patch in appearance. The coefficient of kinetic friction of the patch against 10 adult men and women was determined by the JIS P8147 modification method described above, and as a result, the coefficient of kinetic friction was in the range of 0.35 to 0.80, and it was confirmed that the surface of the patch was excellent in smoothness against the skin for all the test persons. Other characteristics are also the same as those of the patch material of example 1. The results are shown in Table 1.

Examples 3 to 9 and comparative examples 1 to 6

As shown in table 1, a patch was produced in the same manner as in example 2 except that US2268(Tg ═ 23.1 ℃), U-1223(Tg ═ 29.0 ℃), U-1285, U-2860, and U-1285/U-1223 (9: 1 mixed solution) of ラツクスキン (registered trademark) series, manufactured by セイコ co-production (ltd), were used as the polyurethane elastomer solution, and the thickness of the base layer and the thickness of the adhesive layer were changed. The results are shown in Table 1.

Fig. 2 is an image of a confocal microscope obtained by applying the patch produced in example 4 (the thickness of the base material layer was 1 μm, and the thickness of the adhesive layer was 2 μm) to the skin surface of a human body, transferring and attaching the patch using a dental impression material, and using the obtained model. The left half of fig. 2 shows the back surface of the patch, and the right half shows the fine structure of the skin surface.

As shown in fig. 2, when the patch of the present invention is applied to the skin surface of a human body, the patch adheres along the skin surface having fine irregularities such as skin texture, and the patch assumes a state in which the fine texture structure of the skin surface is transferred to the back surface, and the application position is inconspicuous.

Fig. 3 is an image of a confocal microscope obtained by applying the patch (the thickness of the base material layer was 18 μm, and the thickness of the adhesive layer was 7 μm) prepared in comparative example 4 to the skin surface of a human body, transferring and attaching the attached state using a dental impression material, and using the obtained model. The left half of fig. 3 shows the back surface of the patch, and the right half shows the fine structure of the skin surface.

As shown in fig. 3, the patch of comparative example 4 did not satisfy the conditions defined in claim 1 of the present invention, and therefore, in the applied state, the patch could not adhere to the fine uneven surface of the skin, and was in a state of protruding as if it were, and the fine texture structure on the skin surface could not be transferred to the back surface, and therefore the applied position was noticeable.

[ Table 1]

(conclusion)

The adhesive materials of examples 2 to 9 had almost no conspicuous sticking position, no foreign body sensation, and good adhesion.

On the other hand, the patch materials of comparative examples 1 to 5 had good adhesion, but did not satisfy the conditions defined in claim 1 of the present invention, so that the patch position was noticed and had a foreign body sensation. The adhesive strength of the patch of comparative example 6 was insufficient.

Examples 10 to 17 and comparative examples 7 to 8

Various patches were produced in the same manner as in example 1, except that the thickness of the adhesive layer in example 1 was changed. The results are shown in Table 2.

[ Table 2]

From the results in table 2, it is understood that the adhesive layer has a large thickness or a large adhesive force, and the ease of peeling from the skin surface is low.

[ comparative examples 9 to 11]

3 kinds of patches having different thicknesses of the base material layer were produced in the same manner as in example 1, except that polyethylene terephthalate (PET) was used instead of the polyurethane elastomer in example 1. The results are shown in Table 3.

[ Table 3]

As is clear from the results in table 3, even when the PET film is thin, the sticking position of the patch is easily noticeable and has a foreign body sensation. Further, since the base material layer made of the PET film has low stretchability, the base material layer is broken during attachment, and good adhesiveness cannot be obtained.

Industrial applicability

The patch of the present invention can be adhered along the surface of the adherend having fine irregularities, and therefore the patch in the adhered state is inconspicuous. And when the patch of the present invention is used as a skin patch, there is no foreign body sensation.

Therefore, the patch of the present invention can be widely used in the fields of medical patches, emergency bandages, waterproof patches, protective patches for protecting the skin, and the like. Further, the patch of the present invention can be widely used as a patch in the fields of industrial use, stationery use, household use, and the like.

Claims (13)

1. A patch comprising a base material layer and a layer having an adhesive layer provided on one surface thereof,

(a) the substrate layer is a polyurethane elastomer film with a thickness of 1-8 μm,

(b) the adhesive layer has a thickness of 1 to 9 μm, and the adhesive is selected from the group consisting of acrylic adhesives, natural rubber adhesives, synthetic rubber adhesives, silicone adhesives, vinyl ester adhesives, vinyl ether adhesives, and urethane adhesives,

(c) the total thickness of the substrate layer and the adhesive layer is in the range of 2-15 μm,

(d) the 10% tensile loads in the longitudinal direction and the transverse direction of the patch measured according to JIS Z0237 are respectively in the range of 0.03-1.1N/10 mm,

(e) when the 10% tensile load value in the longitudinal direction of the patch is represented by X (N/10mm), the thickness value of the patch is represented by Y (μm), and the thickness value of the base layer is represented by Z (μm), the following relationship is satisfied: the product XY of the 10% tensile load value X and the thickness value Y of the adhesive material is in the range of 0.1-12, or the product XZ of the 10% tensile load value X and the thickness value Z of the base material layer is in the range of 0.05-6.8, and,

(f) the adhesive layer exhibits an adhesive force of 0.15 to 2N/10mm in a 90-degree peel test against a phenol plastic plate prescribed in JIS Z0237.

2. The patch of claim 1, wherein the polyurethane elastomer is a polyether polyurethane elastomer or a polyester polyurethane elastomer.

3. The patch of claim 1, wherein the adhesive layer is an acrylic adhesive layer.

4. The patch according to claim 3, wherein the acrylic adhesive is a copolymer of at least one acrylic monomer selected from alkyl acrylates and alkyl methacrylates each having an alkyl group of 1 to 18 carbon atoms and another monomer copolymerizable with the acrylic monomer.

5. A patch according to claim 3, wherein the acrylic adhesive is a copolymer formed from: 60 to 95 wt% of alkyl acrylate having an alkyl group with 4 to 18 carbon atoms; 1 to 25% by weight of a vinyl monomer having at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an acid anhydride group, an amide group, an amino group, an epoxy group and an alkoxy group; and 0 to 40% by weight of another vinyl monomer copolymerizable with the alkyl acrylate.

6. The patch according to claim 1, wherein the elastomeric film has a longitudinal elongation at break in the range of 130 to 1,000%.

7. The patch according to claim 1, wherein the elastomer for forming the elastomer film has a glass transition temperature in the range of-70 to 20 ℃.

8. The patch according to claim 1, wherein the adhesive layer exhibits an adhesive force in the range of 0.15 to 1N/10 mm.

9. A patch according to claim 1, wherein the surface of the substrate layer opposite to the adhesive layer has been subjected to embossing, whereby the coefficient of dynamic friction of the surface is reduced to 1.0 or less.

10. The patch of claim 1, wherein the patch has a moisture permeability of 1,000g/m²24 hours or longer.

11. The patch of claim 1, wherein at least one of the substrate layer and the adhesive layer comprises a colorant.

12. The patch according to claim 1, wherein the patch has an ultraviolet transmittance of 25% or less at a wavelength of 280 to 400 nm.

13. The patch according to claim 1, further comprising a support layer on a surface of the substrate layer opposite to the adhesive layer, and a separator layer on a surface of the adhesive layer opposite to the substrate layer, thereby having a laminated structure of "support layer/substrate layer/adhesive layer/separator layer".