Summary

The current disclosure relates to perforated tape articles and methods for preparing perforated tape articles. In some embodiments, the tape articles comprise a perforated backing layer with a first major surface and a second major surface, and an adhesive layer with a first major surface and a second major surface, where the second major surface of the adhesive layer is in contact with at least a portion of the first major surface of the perforated backing layer. The backing layer comprises an oriented polymeric film layer with a plurality of perforations where at least some of the perforations form apertures through the oriented polymeric film, and at least some of the perforations through the oriented polymeric film are aligned with apertures through the adhesive layer.

Also disclosed are methods of preparing tape articles. In some embodiments, the method comprises providing a multi-layer adhesive article comprising a stack comprising a backing layer comprising an oriented polymeric film with a first major surface and a second major surface, an adhesive layer with a first major surface and a second major surface, where the second major surface of the adhesive layer is in contact with the first major surface of the backing layer, and a release liner layer with a first major surface and a second major surface, where the second major surface of the release liner layer is in contact with the first major surface of the adhesive layer, and flame or laser perforating through at least the backing layer, and the adhesive layer.

In other embodiments, the method comprises providing a tape backing with a first major surface and a second major surface, perforating the tape backing by flame perforation or laser perforation, and selectively coating an adhesive layer onto the first major surface of the perforated tape backing, such that the adhesive does not contact the perforations.

Brief Description of the Drawings

The present application may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawings. Figure 1 is a cross sectional view of a tape article of this disclosure.

Figure 2 is a cross sectional view of another tape article of this disclosure.

Figure 3A is a micrograph of the surface of a flame perforated tape article of this disclosure.

Figure 3B is a micrograph of a close up view of a flame perforation of the article of Figure 3A.

Figure 4 is an illustration of the flame perforation process.

Figure 5 is a micrograph of another perforated tape article of this disclosure.

Figure 6 is a micrograph of another perforated tape article of this disclosure.

In the following description of the illustrated embodiments, reference is made to the accompanying drawings, in which is shown by way of illustration, various embodiments in which the disclosure may be practiced. It is to be understood that the embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure. The figures are not necessarily to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

Detailed Description

The use of adhesive products in the medical industry has long been prevalent and is increasing. However, while adhesives and adhesive articles have shown themselves to be very useful for medical applications, there are also issues in the use of adhesives and adhesive articles. While many medical adhesive articles are directly applied to wound areas, a wide range of medical articles, such as tapes and drapes, are not applied to the wound area itself but rather play a supporting role to treatment such as holding absorbent materials or medical devices in place on the skin. Examples of medical devices that are held in place with tapes include drapes, tubing, catheters, ostomy appliances, and sensors. Additional uses for medical tapes include a wide variety of applications where tape is applied to the skin of a patient. Examples include holding a patient to an operating or treatment table, covering a part of a patient such as holding eyes closed during surgery, or immobilizing a hand during surgery to the hand, or to overlay a wound closure, not as a wound dressing but to hold the wound closed especially when the wound is closed with staples or sutures.

Medical adhesives have a wide array of desired properties. Among these properties are the typical adhesive requisites of sufficient peel adhesion and shear holding power, as well as flexibility so as to bend with the body, a high moisture vapor transmission rate (MVTR) and low medical adhesive-related skin injury (MARSI).

MVTR is a measure of the passage of water vapor through a substance or barrier. Because perspiration naturally occurs on the skin, if the MVTR of a material or adhesive system is low, this can result in moisture accumulation between the skin and the adhesive that can cause the adhesive to “float off’ or peel away and also can promote other detrimental effects such as bacterial growth and skin irritation. Therefore, much work has focused upon the development of adhesive systems that have a high MVTR.

In addition to these already difficult to achieve properties additional requirements are desired, including optical properties, such as optical transparency to permit one to see through the adhesive article. Increasingly, optical properties of medical adhesive tapes have become more important. In US Patent No. 6,461,467, the term “substantially contact transparent” is used to describe their articles and meaning that when adhered to a patient’s skin, a wound or catheter site can be visually monitored through those portions of the backing and pressure sensitive adhesive or adhesives in contact with the patient’s skin without requiring removal of the dressing.

Many medical tapes require the transport of moisture and other fluids in order to preserve skin health and aid in the healing process. In such applications, adhesives with perforations may provide a useful means to control permeation rates of such material, while imparting many other desired features such as hand tear able features, adhering gently to skin, flexing with movement, while mechanically hold securely when over taped onto itself and being transparent enough to see through to tubing and patients skin.

Various techniques have been used to achieve tape articles that have fluid transport properties, such as the use of non-woven tape backings. One issue with such backings is that they often are not optically transparent. Additionally, backings with fluid transparent properties need to be paired with adhesives that likewise have fluid transport properties. This is typically achieved either by using a discontinuous layer of adhesive or by selecting an adhesive that is fluid permeable. Either of these techniques can have issues and can be generally expensive requiring the use of either relatively expensive materials or specialized coating techniques.

Another technique that can be used to achieve greater fluid transport properties in an adhesive article is to pierce the adhesive layer and backing with a hot needle. While not wishing to be bound by theory, it is believed that this technique can have drawbacks due to the fact the adhesive can flow into the formed needle holes and thus at least partially restrict the fluid transport properties.

Additionally, a wide range of backings are not suitable for use as medical backings because they lack flexibility and are not moisture permeable. An example of such a backing is BOPP (biaxially oriented polypropylene), a very inexpensive tape backing and has the desirable property of optical transparency. However, BOPP is relatively inflexible and non-permeable. Therefore, it is desirable to modify backing materials like BOPP such that these backing materials can be used to prepare medical articles with optical transparency, flexibility, and moisture permeability.

Disclosed herein are medical articles comprising a perforated backing layer and an adhesive layer disposed on the perforated backing layer, where the backing layer comprises an oriented polymeric fdm layer with a plurality of perforations where at least some of the perforations form apertures through the oriented polymeric fdm, and at least some of these perforations are aligned with apertures through the adhesive layer. Also disclosed are methods of preparing these medical articles. While not wishing to be bound by theory, it is believed that perforating the backing and adhesive layer at the same time while they are in contact with a release liner helps to provide stability to the perforations preventing adhesive flow from closing up the perforations and giving not only the desirable mechanical properties (flexibility and hand-tearability) but also desirable MVTR properties.

Additionally, this same methodology can be used to prepare tapes for a wider range of applications where the same properties as desired for medical uses, especially MVTR properties. Therefore, the medical tapes described herein can have a wide range of uses and are not limited to medical applications.

The term “adhesive” as used herein refers to polymeric compositions useful to adhere together two adherends. Examples of adhesives are pressure sensitive adhesives. Pressure sensitive adhesive compositions are well known to those of ordinary skill in the art to possess properties including the following: (1) aggressive and permanent tack, (2) adherence with no more than finger pressure, (3) sufficient ability to hold onto an adherend, and (4) sufficient cohesive strength to be cleanly removable from the adherend. Materials that have been found to function well as pressure sensitive adhesives are polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear holding power. Obtaining the proper balance of properties is not a simple process.

The terms “Tg” and “glass transition temperature” are used interchangeably. If measured, Tg values are determined by Differential Scanning Calorimetry (DSC) at a scan rate of 10°C/minute, unless otherwise indicated. Typically, Tg values for copolymers are not measured but are calculated using the well-known Fox Equation, using the homopolymer Tg values provided by the monomer supplier, as is understood by one of skill in the art.

The term “room temperature” refers to ambient temperature, generally 20-22°C, unless otherwise noted.

The term “(meth)acrylate” refers to monomeric acrylic or methacrylic esters of alcohols. Acrylate and methacrylate monomers or oligomers are referred to collectively herein as "(meth)acrylates”. Polymers described as “(meth)acrylate-based” are polymers or copolymers prepared primarily (greater than 50% by weight) from (meth)acrylate monomers and may include additional ethylenically unsaturated monomers.

The terms “siloxane-based” as used herein refer to polymers or units of polymers that contain siloxane units. The terms silicone or siloxane are used interchangeably and refer to units with dialkyl or diaryl siloxane (-SiR.20-) repeating units.

The term “adjacent” as used herein when referring to two layers means that the two layers are in proximity with one another with no intervening open space between them. They may be in direct contact with one another (e.g. laminated together) or there may be intervening layers.

The terms “polymer” and “macromolecule” are used herein consistent with their common usage in chemistry. Polymers and macromolecules are composed of many repeated subunits. As used herein, the term “macromolecule” is used to describe a group atached to a monomer that has multiple repeating units. The term “polymer” is used to describe the resultant material formed from a polymerization reaction.

The term “alkyl” refers to a monovalent group that is a radical of an alkane, which is a saturated hydrocarbon. The alkyl can be linear, branched, cyclic, or combinations thereof and typically has 1 to 20 carbon atoms. In some embodiments, the alkyl group contains 1 to 18, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, and ethylhexyl.

The term “aryl” refers to a monovalent group that is aromatic and carbocyclic. The aryl can have one to five rings that are connected to or fused to the aromatic ring. The other ring structures can be aromatic, non-aromatic, or combinations thereof. Examples of aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, anthryl, naphthyl, acenaphthyl, anthraquinonyl, phenanthryl, anthracenyl, pyrenyl, peryl enyl, and fluorenyl.

The term “machine direction” (MD) as used herein refers to lengthwise direction. The terms “MD” and “downweb direction” are used interchangeably in this disclosure.

The term “transverse direction” (TD) refers to the crosswise direction. The terms “TD” and “crossweb direction” are used interchangeably in this disclosure.

Disclosed herein are tape articles, especially medical tape articles. In some embodiments, the tape article comprises a perforated backing layer with a first major surface and a second major surface, and an adhesive layer with a first major surface and a second major surface, where the second major surface of the adhesive layer is in contact with at least a portion of the first major surface of the perforated backing layer. The adhesive layer can be continuous or discontinuous. The backing layer comprises an oriented polymeric film layer with a plurality of perforations where at least some of the perforations form apertures through the oriented polymeric film, and where at least some of the perforations through the oriented polymeric film are aligned with apertures through the adhesive layer. In some embodiments, the tape article is optically transparent.

A wide variety of polymeric materials may be used to form the backing layer. Suitable backing layer materials include polyolefins, such as polypropylene, polyester, such as PET (polyester terephthalate), and polyimides. The backing layer is oriented, meaning that the backing layer has been tentered or stretched in one or two dimensions in order to orient the film. The process of orienting film is described in Volume 12 of The Encyclopedia of Polymer Science and Engineering, 2nd edition, pages 193 to 216. A typical process for fabricating biaxially oriented fdms comprises four main steps: (1) melt extrusion of a resin and quenching it to form a web, (2) drawing the web in the longitudinal or machine direction, (3) subsequently or simultaneously drawing the web in the transverse direction to create a fdm, and (4) heat setting the fdm. Further discussion on the orientation of polymeric fdms can be found, for example in the PCT Publication WO 2006/130142.

A particularly suitable backing layer is BOPP (biaxially oriented polypropylene). An example of a BOPP fdm is SBOPP (simultaneous biaxially orientated polypropylene) formed as described in US Patent Publication No. 2004/0184150.

In some embodiments, the tape backing layer is optically transparent. In other embodiments, the tape backing layer is optically opaque or partially opaque. As used herein, the term optically transparent refers to an article, fdm, or adhesive that one can view an object through with the naked eye without the object being distorted or obscured. In many embodiments, the current tapes are optically transparent, meaning, in general, that they have a % Transmission (%T) over at least a portion of the visible light spectrum (about 400 to about 700 nm) of at least 85%, a haze of less than 40%, and clarity of at least 50%. What was discovered is that the tapes of the current disclosure retain their optical properties upon over-taping. The tapes retain their transparency such that a two- layer stack while having a lower % Transmission, a higher haze and a lower clarity than a single layer of the tape, the properties are such that it is possible to clearly view through the two layers of tape. In some embodiments, the two-layer stack has a %T of at least 80%, a haze of less than 70%, and a clarity of at least 30%.

To further clarify the optical properties, in general terms the optical properties can be described in the following general terms:

• % Transmission, as the term implies, is a measure of the amount of light transmitted, i.e. to the ratio of the incident light to the output light for an optical object.

• Haze is the measurement of wide-angle scattering and causes a loss of contrast or a milky appearance.

• Clarity is the measure of narrow-angle scattering and causes the detail of an object to be compromised when viewing it though the substrate. Clarity is also distance-dependent, which means that the farther the object is being viewed through the substrate, the worse its detail becomes.

The higher the haze and the lower the clarity, the more diffusion is occurring. While haze and clarity do not reduce or affect transmission of light, the resulting diffusion can lead to visual aberrations and discrepancies.

In some embodiments, the perforated backing layer also comprises a low adhesion coating on the second major surface of the perforated backing layer. This is especially true if the adhesive article is to be supplied in the form of a roll. Many tapes are supplied as rolls, where the adhesive layer contacts the non-adhesive “back” side of the backing upon being rolled up. Often this backside surface of the backing has a low adhesion or release coating on it to permit the roll to be unwound. These low adhesion coatings are often called “low adhesion backsizes” or LABs. Many factors control whether a LAB coating is necessary or desirable, including the nature of the adhesive, the composition and topography of the backing, and the desired use for the tape article. For example, some polyolefmic backings have a sufficiently low surface energy that a LAB coating is not required when used with some classes of pressure sensitive adhesives. Additionally, as will be explained below, the formation of rims around the perforations of the perforated backing layer can additionally affect the need for a LAB coating.

The perforated backing layer can have a wide range of thicknesses. In some embodiments, the perforated backing layer has a thickness of 15-100 micrometers (0.6-4 mils).

The perforations can have a wide variety of shapes and can be arrayed in a wide variety of patterns. Suitable shapes include ovals, circles, triangles, diamonds, stars, squares, rectangles, plus signs, and the like. In some embodiments, the perforations are oval-shaped. This shape has been found to be very suitable for preparing hand tearable articles.

The perforations may be arrayed randomly or in a well-defined pattern. In some embodiments, the perforations are arrayed in intersecting lines. These intersecting lines aid in making the article hand tearable, as each of the lines provide a focus of stress permitting tears that follow these lines.

The perforations in the backing layer and adhesive layer are prepared by flame perforation or laser perforation. In many embodiments, the perforations are formed by flame perforation. Examples of suitable flame perforation devices are described in the PCT Patent Publications WO 2009/014881, WO 2015/100319, and WO 2016/105501. These applications describe the effect of flame perforation on tape backings to make the tape backings hand tearable in both the machine direction (MD) direction and the crosswise or transverse direction (TD). In this disclosure, MD is generally referred as the downweb direction and TD is referred to as the crossweb direction.

In the flame perforated articles of this disclosure, a stack is formed, where the stack comprises a backing layer, an adhesive layer, and a release liner. The stack is then flame perforated as described below to form the article. In some embodiments, the flame perforation is carried out on the backing layer side of the stack, in other embodiments, the flame perforation is carried out on the release liner side of the stack. When the flame perforation is carried out on the backing layer side of the stack, the flame perforation can be carried out in such a way that the flame perforation passes through the backing layer, the adhesive layer, and may partially perforate the release liner layer or it may fully pass through the release liner layer. In embodiments where the flame perforation is carried out on the release liner side of the stack, the flame perforation fully perforates the release liner layer, the adhesive layer, and the backing layer.

As was mentioned above, the perforations penetrate both the backing layer and the adhesive layer. In some embodiments, the perforations are arrayed in a pattern. The pattern may be arrayed in the downweb direction, the crossweb direction, or in both directions. As disclosed in the teachings listed above, one effect of these patterns is to impart to the tape articles hand tearability in both the downweb direction and the crossweb direction.

The perforated articles may be better understood by referring to the Figures. Figure 1 shows an example of an article of this disclosure. Figure 1 shows article 100, that can be prepared by flame perforating through the backing layer side of the stack. Article 100 has backing layer 110, adhesive layer 120 and release liner layer 130. Flame perforations 140 pass through backing layer 110 and adhesive layer 120 and partially penetrate release liner layer 130.

Figure 2 shows article 200 that can be prepared by flame perforating through the release liner layer side of the stack. Article 200 has backing layer 210, adhesive layer 220 and release liner layer 230. Flame perforations 240 pass through backing layer 210, adhesive layer 220, and fully penetrates release liner layer 230.

Figures 3A and 3B show microographs of flame perforated articles of this disclosure. In Figure 3A, the perforations 340 are oval-shaped and are arrayed in a pattern. The pattern is aligned in such a way as to give hand tearability in two directions, both the MD and TD. Figure 3B shows a close up view of a perforation 340. In perforation 340, raised edge 341 is visible. It has been observed that the flame perforation process forms raised edges on the perforations, similar to the rim of a volcano. These raised edges protrude from the surface of the backing layer. The presence of these slight protrusions on the edges of the perforations provide an elevated area above the surface of the backing layer. The perforations thus not provide avenues for moisture transmission through the articles, but also because of the protrusions on the edges of the perforations, the perforations can affect the adhesion properties of the backing layer in a variety of ways, in some instances, contradictory ways. In some embodiments, the protrusions on the edge of the perforations can selectively decrease the adhesion of an adhesive to the backing layer, in other instances, the protrusions on the edge of the perforations can selectively increase the adhesion of an adhesive to the backing layer.

The variation in the adhesion caused by the protrusions on the edge of the perforations depends on a variety of different parameters. One parameter is whether there is a LAB coating on the backing layer or not. Frequently, when articles are supplied in the form of a roll, a LAB coating is supplied on the non-adhesive surface of the backing to prevent the adhesive from binding too tightly to the backing surface and thus not be able to be unrolled. However, in some tape roll articles no LAB coating is necessary because the polymer of the backing layer has a sufficiently low surface energy that the adhesive does not adhere too strongly to the backside of the backing layer. In these embodiments, often a primer layer or surface modification is carried out on side of the backing layer on which the adhesive is coated such that the adhesive adheres more strongly to that surface of the backing layer than to the backside of the backing layer. In these embodiments, when a LAB coating is not used, the protrusions on the edges of the perforations can decrease the adhesion of an adhesive layer to the backing layer when the article is rolled upon itself. This decrease in adhesion results from the physical effect of decreasing the surface contact of the adhesive layer to the backside of the backing layer. However, if a LAB coating is present, the protrusions on the edge of the perforations can have the opposite effect. While not wishing to be bound by theory, it is believed that the protrusions are formed when selective melting of a small portion of the fdm article in the flame or laser perforation processes, the stresses present in the backing layer cause the molten polymeric material to “snap back” or flow to the edges to form the protrusions. Since the LAB coating is a very thin coating, the protrusions thus contain a very small quantity of LAB material and the LAB material is not necessarily on the surface of the protrusions. Thus, the protrusions may have a higher surface energy than the surrounding LAB-coated flat backing portions. Therefore, the protrusions can form surfaces that are more adhesive-friendly to which an adhesive can bond more strongly than to the LAB-coated backing. This is particularly noticeable when the tape is over-taped. A variety of tapes are designed to wrap upon themselves in use or are over-taped. Examples of these types of tapes are athletic tapes, duct tapes, electrical tapes, as well as a variety of medical tapes. By over-taping it is meant that more than one layer of tape is applied, where the second layer is adhered to at least a portion of the backside of the first layer of tape. The over-taping may involve the second tape layer directly covering the first tape layer, or it may be in a variety of patterns such as an X-shape where the center of the X is attached to a medical device that is desired to be secured to the patient. Even if each tape has some level of transparency, upon over-taping the transparency can be lost.

Optical properties in multi-layer articles are complicated because with each added layer, a new interface is generated. Whenever an interface is present the possibility of optical interference is present. A frequent issue is refraction. Refraction occurs when a visible light ray encounters the interface when the materials that form the interface have different indices of refraction. This phenomenon is described by Snell’s Law. A commonly observed example of this phenomenon is encountered by the air/water interface. If one places an object, like a canoe paddle in the water, the paddle appears to be bent, as a result of the refraction of visible light at the air/water interface.

In some embodiments, the adhesive articles of this disclosure are transparent medical tapes that are capable of being over-taped and retain their transparency. In some embodiments, the over-taped articles are even optically clear. Optical transparency and optical clarity have been defined above. When over-taping tapes with a LAB coating, the LAB coating can decrease the adhesion of the adhesive layer to the backside of the tape that is being over-taped. The perforated articles of this disclosure can overcome issues with over-taping, not only by decreasing the quantity of backing surface available for adhesion (the perforations, as holes in the backing, decrease the quantity of surface available for bonding) but also the protrusions on the edge of the perforations provide bonding surfaces for the adhesive as described above.

A summary of a flame perforation method suitable for use to prepare the articles of this disclosure is summarized in Figure 4. The flame perforation process comprises chilled backing roll 490 with a pattern of holes etched into the backing roll. The oriented fdm construction 460 travels tightly around the etched backing roll, and under a natural gas flame jet 480. A natural gas mixture 470 is supplied to the natural gas flame jet 480. The fdm construction is suspended over these etched holes while under the flame. The fdm construction is not cooled over the holes by the backing roll at this time, thus the oriented fdm construction melts and pops open until the fdm reaches the chilled backing roll, and thus forms perforations. In the perforated fdm construction 465, holes are formed with a rim of melted polymer created around each hole.

In other embodiments the perforations are formed by using laser perforation. Lasers such as CO2 lasers are suitable laser perforation devices. Laser perforation, sometimes called drilling, can be carried out using a balance of peak power and rise/fall times. When drilling and perforating, coupling the energy into the material efficiently yields clean, accurate holes through the material. The laser operates in a pulsed mode to remove material steadily, until penetration occurs and a hole forms. Pulses with discreet durations and energy levels create very small, repeatable hole diameters.

The medical tape articles of this disclosure also include an adhesive layer. In some embodiments, the adhesive layer comprises a (meth)acrylate pressure sensitive adhesive, a siloxane-based pressure sensitive adhesive, or a blend or bi-layer thereof. The adhesive layer may be continuous of discontinuous.

Particularly suitable (meth)acrylate-based pressure sensitive adhesives include copolymers derived from: (A) at least one monoethylenically unsaturated alkyl (meth) acrylate monomer (i.e., alkyl acrylate and alkyl methacrylate monomer); and (B) at least one monoethylenically unsaturated free -radically copolymerizable reinforcing monomer. The reinforcing monomer has a homopolymer glass transition temperature (Tg) higher than that of the alkyl (meth)acrylate monomer and is one that increases the glass transition temperature and cohesive strength of the resultant copolymer. Herein, "copolymer" refers to polymers containing two or more different monomers, including terpolymers, tetrapolymers, etc.

Monomer A, which is a monoethylenically unsaturated alkyl acrylate or methacrylate (i.e., (meth)acrylic acid ester), contributes to the flexibility and tack of the copolymer. Generally, monomer A has a homopolymer Tg of no greater than about 0°C. Typically, the alkyl group of the (meth)acrylate has an average of about 4 to about 20 carbon atoms, or an average of about 4 to about 14 carbon atoms. The alkyl group can optionally contain oxygen atoms in the chain thereby forming ethers or alkoxy ethers, for example. Examples of monomer A include, but are not limited to, 2-methylbutyl acrylate, isooctyl acrylate, lauryl acrylate, 4- methyl-2-pentyl acrylate, isoamyl acrylate, sec-butyl acrylate, n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, isodecyl acrylate, isodecyl methacrylate, and isononyl acrylate. Other examples include, but are not limited to, poly-ethoxylated or -propoxylated methoxy (meth)acrylates such as acrylates of CARBOWAX (commercially available from Union Carbide) and NK ester AM90G (commercially available from Shin Nakamura Chemical, Ltd., Japan). Suitable monoethylenically unsaturated (meth)acrylates that can be used as monomer A include isooctyl acrylate, 2 -ethyl -hexyl acrylate, and n- butyl acrylate. Combinations of various monomers categorized as an A monomer can be used to make the copolymer.

Monomer B, which is a monoethylenically unsaturated free- radically copolymerizable reinforcing monomer, increases the glass transition temperature and cohesive strength of the copolymer. Generally, monomer B has a homopolymer Tg of at least about 10°C. Typically, monomer B is a reinforcing (meth)acrylic monomer, including an acrylic acid, a methacrylic acid, an acrylamide, or a (meth)acrylate. Examples of monomer B include, but are not limited to, acrylamides, such as acrylamide, methacrylamide, N-methyl acrylamide, N-ethyl acrylamide, N- hydroxyethyl acrylamide, diacetone acrylamide, N,N-dimethyl acrylamide, N, N-diethyl acrylamide, N-ethyl-N- aminoethyl acrylamide, N-ethyl-N- hydroxyethyl acrylamide, N,N-dihydroxy ethyl acrylamide, t-butyl acrylamide, N,N-dimethylaminoethyl acrylamide, and N-octyl acrylamide. Other examples of monomer B include itaconic acid, crotonic acid, maleic acid, fumaric acid, 2,2-(diethoxy)ethyl acrylate, 2-hydroxyethyl acrylate or methacrylate, 3 -hydroxypropyl acrylate or methacrylate, methyl methacrylate, isobomyl acrylate, 2- (phenoxy)ethyl acrylate or methacrylate, biphenylyl acrylate, t-butylphenyl acrylate, cyclohexyl acrylate, dimethyladamantyl acrylate, 2-naphthyl acrylate, phenyl acrylate, N- vinyl formamide, N-vinyl acetamide, N-vinyl pyrrolidone, and N-vinyl caprolactam. Particularly suitable reinforcing acrylic monomers that can be used as monomer B include acrylic acid and acrylamide. Combinations of various reinforcing monoethylenically unsaturated monomers categorized as a B monomer can be used to make the copolymer.

Generally, the (meth)acrylate copolymer is formulated to have a resultant Tg of less than about 0°C and more typically, less than about -10°C. Such (meth)acrylate copolymers generally include about 60 parts to about 98 parts per hundred of at least one monomer A and about 2 parts to about 40 parts per hundred of at least one monomer B. In some embodiments, the (meth)acrylate copolymers have about 85 parts to about 98 parts per hundred or at least one monomer A and about 2 parts to about 15 parts of at least one monomer B.

Examples of suitable (meth)acrylate-based pressure sensitive adhesives that can be applied to skin are described in U.S. Patent No. RE 24,906. In some embodiments, a 97:3 iso-octyl acrylate: acrylamide copolymer adhesive can be used or a 70: 15: 15 isooctyl acrylate: ethyleneoxide acrylate: acrylic acid terpolymer, as described in US Patent No. 4,737,410. Other useful adhesives are described in US Patent Nos. 3,389,827, 4,112,213, 4,310,509, and 4,323,557.

Another class of suitable pressure sensitive adhesive is siloxane-based adhesives. The terms “silicone” and siloxane” are used interchangeably herein. The siloxane-based adhesive compositions comprise at least one siloxane elastomeric polymer and may contain other components such as tackifying resins. The elastomeric polymers include for example, urea-based siloxane copolymers, oxamide-based siloxane copolymers, amide- based siloxane copolymers, urethane-based siloxane copolymers, and mixtures thereof.

One example of a useful class of siloxane elastomeric polymers is urea-based silicone polymers such as silicone polyurea block copolymers. Silicone polyurea block copolymers include the reaction product of a polydiorganosiloxane diamine (also referred to as a silicone diamine), a diisocyanate, and optionally an organic polyamine. Useful silicone polyurea block copolymers are disclosed in, e.g., U.S. Patent Nos. 5,512,650, 5,214,119, 5,461,134, and 7,153,924 and PCT Publication Nos. WO 96/35458, WO 98/17726, WO 96/34028, WO 96/34030 and WO 97/40103.

Another useful class of silicone elastomeric polymers are oxamide-based polymers such as polydiorganosiloxane polyoxamide block copolymers. Examples of polydiorganosiloxane poly oxamide block copolymers are presented, for example, in US Patent Publication No. 2007-0148475.

Another useful class of silicone elastomeric polymer is amide-based silicone polymers. Such polymers are similar to the urea-based polymers, containing amide linkages (-N(D)-C(O)-) instead of urea linkages (-N(D)-C(O)-N(D)-), where C(O) represents a carbonyl group and D is a hydrogen or alkyl group.

Such polymers may be prepared in a variety of different ways. Starting from the polydiorganosiloxane diamine described above in Formula II, the amide-based polymer can be prepared by reaction with a poly-carboxylic acid or a poly-carboxylic acid derivative such as, for example di-esters. In some embodiments, an amide-based silicone elastomer is prepared by the reaction of a polydiorganosiloxane diamine and di-methyl salicylate of adipic acid.

Another useful class of silicone elastomeric polymer is urethane-based silicone polymers such as silicone polyurea-urethane block copolymers. Silicone polyureaurethane block copolymers include the reaction product of a polydiorganosiloxane diamine (also referred to as silicone diamine), a diisocyanate, and an organic polyol. Such materials are structurally very similar to the structure of Formula I except that the -N(D)- B-N(D)- links are replaced by -O-B-O- links. Examples are such polymers are presented, for example, in US Patent No. 5,214,119.

In some embodiments, the siloxane-based pressure sensitive adhesive further comprises a siloxane tackifying resin. Siloxane tackifying resins have in the past been referred to as “silicate” tackifying resins, but that nomenclature has been replaced with the term “siloxane tackifying resin”. The siloxane tackifying resins are added in sufficient quantity to achieve the desired tackiness and level of adhesion. In some embodiments, a plurality of siloxane tackifying resins can be used to achieve desired performance.

Suitable siloxane tackifying resins are commercially available from sources such as Dow Coming (e.g., DC 2-7066), Momentive Performance Materials (e.g., SR545 and SR1000), and Wacker Chemie AG (e.g., BELSIL TMS-803). The pressure sensitive adhesive may further comprise one or more optional additives as long as the additives do not interfere with the optical or other desirable properties of the pressure sensitive adhesive layer. Among the suitable additives are antimicrobial agents. US Patent Application Publications 2018/0280591 and 2015/0238444, disclose antimicrobial agents dispersed throughout an adhesive composition. For example, chlorohexidine gluconate can be included within the pressuresensitive acrylate adhesive to provide continuous antimicrobial activity.

As described above, the flame or laser perforated adhesive articles of this disclosure have an advantage over articles that have been perforated by, for example, a hot needle, where the adhesive can flow back to fill or at least partially fill the hole formed by the needle. In the flame or laser perforated articles, the adhesive layer is perforated by the flame or by a laser. While not wishing to be bound by theory, it is believed that unlike perforation by a needle where the pressure sensitive adhesive is merely pushed aside temporarily, permitting easy flow back to refill the hole, in the current process a hole is burned through the adhesive leaving a gap in the adhesive layer. Additionally, the formation of rims around the edge of the perforations as described above additionally aids in holding the adhesive layer in place, preventing the flow of adhesive into the perforations.

The pressure sensitive adhesive can have a variety of thicknesses, typically the layer is from 15-100 micrometers (0.6-4 mils) in thickness.

The adhesive layer is covered with a release liner to protect the adhesive layer until used and to support the adhesive layer/backing layer construction during the perforation process. A wide range of release liners are suitable for use in the adhesive articles of this disclosure. A wide variety of release liners are suitable. Release liners are commonly used and well understood in the adhesive arts. Exemplary release liners include those prepared from paper (e.g., Kraft paper) or polymeric material (e.g., polyolefins such as polyethylene or polypropylene, ethylene vinyl acetate, polyurethanes, polyesters such as polyethylene terephthalate, and the like, and combinations thereof). At least some release liners are coated with a layer of a release agent such as a silicone-containing material or a fluorocarbon-containing material. Exemplary release liners include, but are not limited to, liners commercially available from CP Film (Martinsville, Va.) under the trade designation "T-30" and "T-10" that have a silicone release coating on polyethylene terephthalate film.

The release liner may have a wide range of thicknesses. In some embodiments, the release liner has a thickness of 15-100 micrometers (0.6-4 mils).

The medical tape articles of this disclosure have a wide array of desirable properties. Among these properties are flexibility, optical transparency, and a desirable moisture vapor transmission rate. Flexibility in this context refers to a comparison of a tape article with the same backing film where one of the tape backings is perforated as described herein and the other is non-perforated. The perforated article has increased bendability relative to the article that is non-perforated. Along with the flexibility the tape articles are hand-tearable in either the downweb or the crossweb direction. In some embodiments, the tape article has a moisture vapor transmission rate of greater than 500 g/cm ² .

Also disclosed herein are methods for preparing medical tape articles. In some embodiments, the method of preparing a medical tape article comprises providing a multilayer adhesive article comprising a backing layer and an adhesive layer, and a release layer and flame or laser perforating through the backing layer, and adhesive layer. In some embodiments, the perforations extend into the release layer, but not through the release layer. In other embodiments, the perforations extend through the release layer. The backing layer has been described above and comprises an oriented polymeric film with a first major surface and a second major surface. The adhesive layer has been described above and comprises a first major surface and a second major surface, where the second major surface of the adhesive layer is in contact with the first major surface of the backing layer. The release layer has been described above and comprises a first major surface and a second major surface, where the second major surface of the release layer is in contact with the first major surface of the adhesive layer.

The multi-layer stack of backing layer/adhesive layer/release layer can be prepared in a variety of ways. In some embodiments, the stack is prepared by contacting together a backing layer, an adhesive layer, and a release layer to form the stack and then the stack is perforated. In other embodiments, a pre-formed tape article comprising a backing layer and an adhesive layer can be contacted to a release layer and the thus-formed stack can then be perforated either by a flame processing or laser processing. The method further comprises removing the release layer to expose the perforated adhesive layer when the article is used. The article has all of the desirable properties described above.

Figures 3A and 3B illustrate examples where the stack is prepared by contacting together a backing layer, and adhesive layer, and a release layer to form the stack and then the stack is perforated. Figure 5 illustrates an example of an article formed by taking a pre-formed tape, contacting the adhesive surface to a release layer, and then perforating the formed multi-layer construction. In Figure 5, a sample of 3M POLYESTER TAPE 8402 was contacted to a release layer and perforated as described in the examples section below. In Figure 5, article 500 has backing layer 510 with plus-shaped perforations 540.

A number of other techniques are also suitable for forming the perforated tape articles that involve the use of separately perforated backing layers, or a separately perforated backing layer and a separately perforated adhesive layer. An example of a method for preparing the articles by separately perforating the backing layer involves preparing a perforated backing layer and then selectively coating an adhesive layer onto the perforated backing layer such that the adhesive does not cover the perforations. The perforated backing layer can be prepared by flame perforation or laser perforation as described above. Selective coating of the adhesive layer can be effected through a wide array of methods such as printing methods including screen printing and inkjet printing.

Other examples involve separately perforating an adhesive layer between two release liners. This perforation can be carried out either by flame perforation or laser perforation as described above. One of the release liners can be removed and the adhesive surface can be contacted to a perforated backing layer, such as by lamination, to form the perforated adhesive articles. In this technique, the perforations on the perforated adhesive are aligned with the perforations on the backing layer. The perforated backing layer can be prepared as described above.

While it is often convenient to prepare the perforated tape articles by preparing a stack of backing laver/adhesive layer/release layer and perforating the stack to form the article in a continuous process, it may in some instances be desirable to assemble the perforated tape articles using separately perforated layers. For example, it may not be conducive or practical to perforate some combinations of backing layers and adhesive layers making the assembly of separately perforated layers a suitable method. Examples

These examples are merely for illustrative purposes only and are not meant to be limiting on the scope of the appended claims. The following abbreviations are used: m = meters; cm = centimeters; dm = decimeters; in = inch; mL = milliliters; N = Newtons; kJ = kiloJoules; g = grams; psi = pounds per square inch; kPa = kiloPascals; min = minutes; hr = hours; btu = British thermal units; °F = degrees Fahrenheit; °C = degrees Celsius.

Table of Abbreviations

Test Methods

180° Peel Adhesion Strength

Peel adhesion strength was measured in the following manner, which generally followed the procedure described in ASTM D 3330-90. Peel adhesion strength was measured at 72°F (22°C) and 50% relative humidity (RH) using a Zwick model Z005 tensile tester (Zwick USA, Kennesaw, GA). A tape test specimen measuring 1 inch (2.54 centimeters) wide by approximately 5 inches (12.7 centimeters) long was applied to a precleaned, flat, rigid substrate of stainless steel (SS), cleaned by wiping once with a solvent (either methyl ethyl ketone or heptane) and a clean lint free tissue, then allowed to air dry prior to use. The SS substrate was 0.052 inches (1.31 millimeters) thick. To apply the tape specimen to the substrate, a mechanical roller machine or hand operated 4.5 pound (ca. 2 kilogram) hard rubber roller was used to ensure intimate contact with the substrate surface. The test specimen was tested immediately after preparation. The free end of the tape test specimen was attached to the load cell apparatus and the specimen was oriented to provide a peel angle of 180°. The substrate was attached to the moveable platen on the instrument. The peel adhesion test was run at a constant rate of 12 inches (30.48 centimeters)/minute and the average peel adhesion force was recorded in ounces/inch and converted to Newtons/decimeter (N/dm). The results of three measurements were averaged to provide the reported values.

MVTR Moisture Vapor Transmission Rate

The upright MVTR was measured according to ASTM E-96-80. A 3.8 cm diameter sample was placed between adhesive-containing surfaces of two foil adhesive rings, each having a 5.1 cm ² elliptical opening. The holes of each ring were carefully aligned. Finger pressure was used to form a foil/sample/foil assembly that was flat, wrinkle free, and had no void areas in the exposed sample.

A 120-mL glass jar was filled with approximately 50 mL of tap water that contained a couple drops of 0.02% (w/w) aqueous Methylene Blue USP (Basic Blue 9, C.I.52015) solution, unless specifically stated in an example. The jar was fitted with a screw -on cap having a 3.8 inch (9.7 cm) diameter hole in the center thereof and with a 4.45 cm diameter rubber washer having an approximately 3.6 cm hole in its center. The rubber washer was placed on the lip of the jar and foil/sample/foil assembly was placed backing side down on the rubber washer. The lid was then screwed loosely on the jar.

The assembly was placed in a chamber at 40°C. and 20% relative humidity for four hours. At the end of four hours, the cap was tightened inside the chamber so that the sample was level with the cap (no bulging) and the rubber washer was in proper seating position.

The foil sample assembly was removed from the chamber and weighed immediately to the nearest 0.01 gram for an initial dry weight, Wl. The assembly was then returned to the chamber for at least 18 hours, the exposure time T1 in hours, after which it was removed and weighed immediately to the nearest 0.01 g for a final dry weight, W2. The MVTR in grams of water vapor transmitted per square meter of sample area per 24 hours can then be calculated using the following formula: MVTR = (Wl-W2)x(4.74xl04)/Tl

Examples

Example 1

The adhesive surface of a piece of Tape- 1 was laminated to a sheet of 1.2 mil (30 micrometer) thick (BOPP) biaxially oriented polypropylene. This construction was then passed through a flame process apparatus with the tape surface facing towards the flame. The process conditions are shown below in Table 1.

Table 1. Process conditions for flame perforation process.

The BOPP film that had been laminated to Tape-1 was then removed from the construction. Both of the resulting materials were inspected, and it was noted that both the BOPP film and Tape-1 contained a set of openings (perforations). The perforations are shown in Figure 6, as element 640. below, which shows a micrograph of the non-adhesive surface of Tape-1. The rims that reside near the opening of each of the perforations as discussed above are also visible.

Samples of perforated Tape-1 were tested for peel adhesion using the Test Method described above. Table 2 shows the peel forces before and after the tape was made permeable with through holes. Table 2. Peel Adhesion of Tape 1 and Example 1.

To test the optical clarity of perforated Tape-1, the tape was adhered to the back of the hand of a test subject. The underlying skin surface and its features were clearly visible in an unflexed state and also during flexure.

To test the flexibility of perforated Tape-1, the tape of the was wrapped around an unbent finger joint and then the finger was bent, straightened again, and bent again showing the flexural accommodation that the perforation imparts on the tape.

Example 2- Laminate structure of the tape of Example 1

The tape of Example 1 was cut into a square section and the nonadhesive side having the raised rims was laminated to the adhesive window of a sample of Tape-2 An orange BIC Highlighter pen was used to draw a line of orange ink along the region where the tape of Example 1 was joined via lamination to Tape-2. The ink was able to flow between the backside of the tape of Example 1 and the adhesive of Tape-2, due to the space created between the protruding rims on the nonadhesive side of the tape of Example 1 and the Tegaderm PSA coating.

Example 3. Over-taping of the tape of Example 1

A i in by 4 in (1.3 cm x 10 cm) tom piece of the Example 1 Tape was grasped at one end and tom approximately in the center lengthwise for 2.75 in (7.0 cm). A clear Bic ballpoint pen with black ink was wrapped in a trouser taped fashion allowing the perforated tape to angle upward and around the pen case. One side was taped first and then the next tom and split side was wound up the pen in the opposing direction causing the two tapes to cross and the second tape adhered to the rims on the first tapes backside. The ink inside the pen was clearly visible and the wrapped sections of the tapes held together under some added tugging force. Next a second similar tape and process was completed on a section of the pen that was solid black and observed that indeed the crossing tapes meshed into the rims of the backside of the tape. Again, a large tugging force was used, and the tapes held.

Example 4. Laser Perforation of Tape-3

A sample of Tape-3 was adhered to a release liner and laser perforated to form a pattern of plus signs as shown in Figure 5. The release liner was removed and the tape was tested for MVTR using the method described above. The data are presented in Table 3.

Table 3. Peel Adhesion of Tape-3 and Example 4.

Example 5:

A fdm of corona-treated SBOPP (simultaneously biaxially oriented polypropylene) fdm with a thickness of 1.2 mils (30 micrometers) and a urethane-based LAB coating on the backside was hot melt coated with PSA-1 to a thickness of 1.1 mils (28 micrometers) to form a tape article. The adhesive surface was covered with a release liner (LOPAREX 1.6 mils (41 micrometers) thick BOPP silicone-coated liner), and the formed construction was flame perforated as described above on the SBOPP fdm side of the article. The release liner was removed. The resulting perforated article is shown in Figures 3A and 3B, where the holes 340 with rims 341 are clearly visible.