adhesive composition

Abstract

The present invention relates to an adhesive composition comprising: (A) a polymer component having a weight-average molecular weight in the range of 1,000 to 100,000 daltons and an average of X nucleophilic functional groups having active hydrogen atoms per molecule, where X is a number having a value of at least 2; and (B) a crosslinking component obtained by reacting (i) a polyisocyanate component having an average of 1.8 to 6 isocyanate functional groups per molecule with at least one of (ii) at least one compound containing a functional group curable by free radical polymerization and further containing a nucleophilic functional group having an active hydrogen atom, and (iii) at least one compound containing a nucleophilic functional group having an active hydrogen atom but no functional group curable by free radical polymerization. The total degree of substitution of polyisocyanate component (i) by compounds (ii) and (iii) is in the range of 0.1 to 0.7, and the molar ratio of unsubstituted isocyanate functional groups in crosslinking component (B) to the nucleophilic functional groups having active hydrogen atoms in polymer component (A) is at least 0.8. The present invention also relates to methods for preparing the adhesive polyurethane compositions, adhesive medical devices comprising the adhesive compositions, and methods for treating wounds using the adhesive medical devices.

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive composition. In particular, the present invention relates to an adhesive composition that has low cytotoxicity and is therefore suitable for medical applications where the adhesive composition comes into direct contact with the skin. The present invention also relates to a method for producing the adhesive composition and to an article comprising the adhesive composition.

[0002] The adhesive composition of the present invention can be used with a variety of substrates, but is particularly useful for skin applications given its low cytotoxicity.

[0003] The adhesive compositions of the present invention may include a curable moiety and may therefore be switchable from a tacky state to a substantially non-tacky state upon initiation of curing of the curable moiety by irradiation with light of an appropriate wavelength, the reduction in tack being evident by a decrease in peel strength of the switched adhesive compared to the unswitched adhesive.

[0004] The switchable adhesive composition is particularly suitable for medical products that are applied to a patient's skin. Before switching, the adhesive forms a strong, durable bond to the skin, and after switching, the low tack state allows the medical product to be easily removed without pain or damage to the underlying tissue. This is particularly useful for patients with delicate skin (e.g., infants and the elderly), as well as patients with trauma or long-term medical conditions that require repeated application of dressings. [Background technology]

[0005] Many medical devices include a layer of pressure-sensitive adhesive to allow the medical device to be attached to a patient's skin. Examples of such medical devices include dressings, surgical drapes, and medical tapes. Adhesives used in medical devices must be sufficiently adhesive to form a strong bond to the skin so that they can resist peeling or accidental removal during use of the medical product. However, traditional adhesives with these properties can cause trauma and / or pain to the patient when the dressing or bandage is removed from the skin. This is particularly true for patients with long-term conditions, such as stoma patients, who require adhesive dressings to be applied repeatedly to the same body part over an extended period of time. It is also true for patients with delicate skin, especially the elderly and infants.

[0006] A class of "switchable" pressure-sensitive adhesives has been developed to address this problem. These adhesives have a high initial peel strength but can be made to undergo a physical and / or chemical change that substantially reduces the peel strength before removal of the adhered product. Thus, the medical product can be removed easily and without causing local trauma or pain to the patient. For an adhesive medical product to be useful, it is further necessary that the reduction in peel strength be achieved in a controlled manner over a relatively short period of time, e.g., from a few seconds to at most a few minutes. Furthermore, the adhesive itself and the switching mechanism must be suitable for use in contact with the skin.

[0007] For convenience, the term "switchable" is used herein to refer to adhesive compositions that can be changed from a tacky state to a substantially non-tacky state. Typically, the peel force reduction with the adhesives of the present invention is about 99% on polished stainless steel and about 90% on skin.

[0008] One form of switchable adhesive is disclosed in U.S. Patent Nos. 5,629,292; 5,729,292; 5,729,292; and 5,829,303. These documents describe adhesives that become less tacky when in contact with water. However, such adhesives are unsuitable for many medical applications where the patient's skin needs to remain dry, such as at a wound site.

[0009] Patent documents 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 200, 210, 220, 230, 240, 250, 260

[0010] Patent documents 8 to 10 disclose adhesives that are switchable when exposed to visible light or low-intensity UV light. The switchable adhesives described in these documents generally include acrylic adhesives based on copolymers of alkyl acrylates, acrylic acid, and / or free-radically polymerizable vinyl moieties that are "modified" or functionalized with attached curable moieties. Typical attached curable moieties are derived from anthracene, cinnamate, maleimide, coumarin, acrylate, and / or methacrylate.

[0011] Patent documents 11 and 12 by the present inventors disclose switchable adhesive compositions based on polyurethane adhesives. Unsaturated curable molecules can be mixed and / or bonded to the polyurethane polymer backbone. Photoinitiated curing of the curable molecules forms a crosslinked network, which reduces the peel strength of the adhesive.

[0012] Despite the above developments, there remains a need in the art for improved switchable adhesives that exhibit the following properties: high peel strength before switching, low peel strength after switching, and short switching times after switching is initiated. It has been found that adhesive formulations with good adhesive properties often demonstrate poor switching ability, and adhesive formulations with good switching ability often demonstrate low peel strength and / or low cohesion (the adhesive has low internal strength such that the bonded material will detach from the surface, leaving adhesive residue on the surface). Therefore, when developing a switchable adhesive, it is particularly challenging to simultaneously obtain high peel strength, high cohesion, and good switching ability.

[0013] Furthermore, there is a need for improved switchable adhesives that provide desirable adhesive and switching properties with low cytotoxicity. Low cytotoxicity is particularly important when adhesives are used in medical applications where the adhesive may remain in contact with the skin for extended periods of time. Adhesives with cytotoxicity above a certain level can cause adverse skin effects such as irritation and inflammation. Achieving low cytotoxicity, and therefore good biocompatibility, is one of the most pressing challenges in the development of adhesives for medical applications.

[0014] The present inventors also disclose a switchable adhesive composition based on polyurethane adhesives and having reduced cytotoxicity in U.S. Patent No. 5,949,299. Specifically, this document identifies low molecular weight compounds (e.g., those having a molecular weight in the range of 150 to 450) as sources of cytotoxicity due to the ability of these compounds to penetrate cell membranes as well as skin.

[0015] There is a continuing need in the art for switchable adhesive compositions that have reduced cytotoxicity. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] US5,032,637 [Patent Document 2] US5,352,516 [Patent Document 3] US4,331,576 [Patent Document 4] US5,182,323 [Patent Document 5] US2013 / 0123678 [Patent Document 6] WO2010 / 129299 [Patent Document 7] WO2013 / 066401 [Patent Document 8] EP0863775 [Patent Document 9] US6,184,264 [Patent Document 10] US6,610,762 [Patent Document 11] WO2016 / 124339 [Patent Document 12] WO2021 / 170711 [Patent Document 13] WO2015 / 132551 [Patent Document 14] WO2015 / 075448 [Patent Document 15] EP2179749 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention has been devised in view of the shortcomings of known switchable pressure-sensitive adhesive systems as described above, and provides an improved switchable adhesive composition having high peel strength, high cohesion, fast switching time, low switched peel strength, and low cytotoxicity. [Means for solving the problem]

[0018] In a first aspect, the present invention provides: (A) a polymer component having a weight average molecular weight in the range of 1,000 to 100,000 daltons and an average of X per molecule of nucleophilic functional groups having active hydrogen atoms, where X represents a number having a value of at least 2; (B) (i) a polyisocyanate component having an average of 1.8 to 6 isocyanate functional groups per molecule, (ii) at least one compound containing a functional group curable by free radical polymerization and further containing a nucleophilic functional group having an active hydrogen atom; and (iii) at least one compound containing a nucleophilic functional group having an active hydrogen atom and no functional group curable by free radical polymerization; and a cross-linking component obtained by reacting the cross-linking component with at least one of 1. An adhesive composition comprising the reaction product of The adhesive composition is provided in which the total degree of substitution of the polyisocyanate component (i) with the compounds (ii) and (iii) is in the range of 0.1 to 0.7, and the molar ratio of the unsubstituted isocyanate functional groups in the crosslinking component (B) to the nucleophilic functional groups having an active hydrogen atom in the polymer component (A) is at least 0.8.

[0019] In a second aspect, the present invention provides: (a) To form the cross-linking component (B), (i) a polyisocyanate component having an average of 1.8 to 6 isocyanate functional groups per molecule, (ii) at least one compound containing a functional group curable by free radical polymerization and further containing a nucleophilic functional group having an active hydrogen atom; and (iii) at least one compound containing a nucleophilic functional group having an active hydrogen atom and no functional group curable by free radical polymerization; wherein the total degree of substitution of polyisocyanate component (i) with compounds (ii) and (iii) is in the range of 0.1 to 0.7; (b) a second step of combining the cross-linking component (B) formed in step (a) with a polymer component (A), the polymer component (A) having a weight average molecular weight in the range of 1,000 to 100,000 daltons and having an average of X nucleophilic functional groups with active hydrogen atoms per molecule, where X represents a number having a value of at least 2; 1. A method for preparing an adhesive composition comprising: The amount of crosslinking component (B) and polyol component (A) is selected so that the molar ratio of unsubstituted isocyanate functional groups in crosslinking component (B) to nucleophilic functional groups having active hydrogen atoms in polymer component (A) is at least 0.8.

[0020] In a third aspect, the present invention provides an adhesive medical device comprising a layer of the adhesive composition described herein disposed on a first carrier film, and a release liner disposed over the layer of adhesive.

[0021] In a fourth aspect, the present invention provides a method of treating a wound using an adhesive medical product according to the third aspect, the method comprising removing the release liner and applying the adhesive dressing to the wound. [Brief explanation of the drawings]

[0022] The invention will now be further described, by way of example only and not by way of limitation, with reference to the drawings in which: [Figure 1] 1 is a cross-sectional view through an adhesive dressing according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view showing an attempt to remove an adhesive dressing from a patient's forearm according to a first embodiment of the present invention, including an enlarged callout in partial cross section showing how removal of the adhesive dressing causes the adhesive composition to protrude. [Figure 3] 1 is a perspective view of an adhesive dressing according to a first embodiment of the present invention undergoing irradiation to effect adhesive switching. FIG. [Figure 4] FIG. 1 is a perspective view illustrating how an adhesive dressing according to a first embodiment of the present invention can be easily removed after switching adhesives. [Figure 5] 5 and 6 are graphs showing the results of Examples 5 to 14. [Figure 6] 5 and 6 are graphs showing the results of Examples 5 to 14. DETAILED DESCRIPTION OF THE INVENTION

[0023] The adhesive composition of the present invention is a reaction product of a polymer component (component (A)) and a crosslinking component (component (B)). Specifically, the adhesive is formed by the reaction of nucleophilic functional groups on the polymer component with free isocyanate groups on the crosslinking component.

[0024] Crosslinking component (B) is obtained by partial reaction of polyisocyanate component (i) with at least one of compounds (ii) containing curable functional groups and compounds (iii) not containing curable functional groups. The total degree of substitution of polyisocyanate component (i) with compounds (ii) and (iii) is controlled within a specified range so that at least a portion of the isocyanate groups remain unreacted and therefore available to react with hydroxy groups of polymer component (A) to form a crosslinked adhesive network containing curable groups.

[0025] The degree of substitution of the polyisocyanate component (i) represents the portion of the isocyanate groups of the polyisocyanate component (i) that has been substituted with nucleophilic functional groups having active hydrogen atoms from the compounds (ii) and (iii), and is as follows:

[0026]

number

[0027] When compound (iii) is not present, the total degree of substitution of polyisocyanate component (i) relates to the degree of substitution with compound (ii). When compound (ii) is not present, the total degree of substitution of polyisocyanate component (i) relates to the degree of substitution with compound (iii). When both compounds (ii) and (iii) are present, the total degree of substitution of polyisocyanate component (i) relates to the total degree of substitution with compound (ii) and compound (iii).

[0028] The partial reaction of polyisocyanate component (i) with compound (ii) and / or compound (iii) results in a product mixture containing a statistical mixture of substituted polyisocyanates. Some individual polyisocyanate molecules will be substituted at all of their isocyanate groups with compound (ii) and / or (iii), while other polyisocyanate molecules will be completely unsubstituted. Still other polyisocyanate molecules will contain one or more substituted isocyanate groups and one or more unsubstituted isocyanate groups in the same molecule. The unsubstituted isocyanate groups are available for reaction with nucleophilic functional groups of polymer component (A).

[0029] When an individual polyisocyanate molecule is fully substituted with compounds (ii) and / or (iii), the resulting compound has no free isocyanate groups and cannot react with polyol component (A). However, when that compound is substituted with compound (ii), it may function as an unbound curing molecule that can participate in the curing reaction that switches the adhesive from a high tack to a low tack state.

[0030] When individual polyisocyanate molecules (i) are partially substituted with compounds (ii) and / or (iii) or unsubstituted, they can react with the nucleophilic functional groups of the polymeric components and thus become bound to the polyurethane adhesive via a urethane / urea / amide bond. Compounds in crosslinking component (B) that have only one unsubstituted isocyanate group form a terminal bond to the polymeric components and thus function to attach the curable molecule to the polymer backbone. Compounds in crosslinking component (B) that have two unsubstituted isocyanate groups can crosslink two nucleophilic groups of the polymeric components to form a crosslinked polymer network.

[0031] Compounds in crosslinking component (B) having three (or more) unsubstituted isocyanate groups can crosslink three (or more) nucleophilic groups of the polymer component, thus forming nodes (or branch points) where multiple polymer end groups are attached to the same polyisocyanate molecule.

[0032] The degree of substitution of polyisocyanate component (i) with compound (ii) and / or compound (iii) has a significant effect on the properties of the adhesive composition. If the degree of substitution is too low, polymer component (A) will be too tightly bonded to the nodes, as described above. This results in reduced mobility of the adhesive and insufficient tack. On the other hand, if the degree of substitution is too high, the crosslinking component will contain a relatively small number of molecules containing two or more unsubstituted isocyanate groups that can crosslink polymer component (A). If the degree of crosslinking is low, the adhesive composition will have poor cohesion, making it difficult to apply and remove the adhesive without leaving residue.

[0033] The tackiness of an adhesive composition has also been found to depend on the ratio of isocyanate groups in the crosslinker to nucleophilic groups in the polymer. This ratio is of paramount importance in polyurethane chemistry and is often expressed as a percentage ([NCO] / [OH] x 100%). It was previously thought that polyurethane adhesives for medical applications should have an NCO index well below 100%, because the additional mobility of the polymer chain adjacent to unbound hydroxy groups and the hydrogen-bonding ability of the unbound hydroxy groups contribute to the adhesive's tackiness. For example, U.S. Patent No. 5,629,493 teaches that the molar ratio of isocyanate functional groups in the crosslinker to hydroxy groups in the polyol component is preferably 0.5 to 0.7. U.S. Patent No. 5,629,493 also relates to polyurethane medical adhesives and specifies an NCO index ranging from 0.45 to 0.69. U.S. Patent No. 5,629,493 discloses pressure-sensitive polyurethane adhesives for medical applications and specifies an NCO index ranging from 0.03 to 0.5.

[0034] It has now been discovered that unbound nucleophilic groups and adjacent polymer chains play an important role in the cytotoxicity of polyurethane adhesives. Attempts to reduce the cytotoxicity of polyurethane adhesives have so far focused on the presence of low-molecular-weight impurities and by-products capable of penetrating skin and cell membranes. However, the present inventors have determined that the adhesive polymer itself can have cytotoxic effects depending on its structure. It is believed that this cytotoxicity is due to the ability of unbound polymer chains to act like surfactants and disrupt cell membranes.

[0035] It has now been found that a significant reduction in cytotoxicity is observed when the molar ratio of unsubstituted isocyanate functional groups in crosslinking component (B) to nucleophilic (e.g., hydroxy) groups in polymer component (A) is at least 0.8 (i.e., an isocyanate index of at least 80%). A high isocyanate index ensures that a high proportion of polymer chains are linked by crosslinking component (B) and therefore cannot contribute to cytotoxicity like surfactants.

[0036] Furthermore, it has been found that sufficient tack (peel strength) is achieved when the crosslinking component is a polyisocyanate partially substituted with compounds (ii) and / or (iii) described herein. Partial substitution of the polyisocyanate not only facilitates the incorporation of curable groups into the composition, but also modifies the bonding of the polymer component to the polyisocyanate so that fewer polymer chains are firmly attached to nodes and the adhesive retains greater chain mobility, thereby contributing to increased tack. Furthermore, it has been found that the statistical mixture of partially substituted isocyanate compounds obtained according to the present invention provides an improved adhesive compared to adhesives formed using unsubstituted polyisocyanates, which have fewer isocyanate groups per molecule. Furthermore, when fewer unbound polymer molecules are present, less plasticization and better cohesive strength are obtained, since this allows for more uniform distribution of crosslinks throughout the adhesive composition.

[0037] The adhesive compositions of the present invention generally have a gel-like consistency with a relatively low density of crosslinks, and are capable of forming polar and van der Waals bonds with the substrate, which give the adhesive composition its tackiness.

[0038] When the crosslinking component (B) has a curable moiety from compound (ii), the curing (or switching) reaction can be initiated, for example, by exposure to long-wavelength UV or visible light in the presence of a photoinitiator. This curing reaction significantly increases the crosslink density within the adhesive composition compared to an unswitched adhesive composition. This reduces the mobility and free volume of the polymer segments of the adhesive composition, meaning that the composition loses its fluidity and essentially becomes an elastic film with little or no tack.

[0039] When a pressure-sensitive adhesive is peeled from a surface to which it is adhered, the energy required is approximately 10 times less than that required from a thermodynamic standpoint, as a result of internal energy losses in the adhesive bulk material, and because at least a portion of the peel force acts in a direction perpendicular to the surface. 2 From 10 4 In the switchable adhesive compositions of the present invention having compound (ii) in the crosslinking component, the dense polymer network formed by the curable functional groups after adhesive switching reduces the tack and flexibility of the bulk material of the composition. Thus, the required peel force is reduced to a value close to that implied by thermodynamic considerations alone.

[0040] Polymer component (A) The polymer component has a weight average molecular weight in the range of 1,000 to 100,000 daltons and has an average of X nucleophilic functional groups with active hydrogen atoms per molecule, where X represents a number having a value of at least 2. The nucleophilic groups of polymer component (A) react with the free isocyanate groups of crosslinking component (B) to form a crosslinked adhesive network.

[0041] The adhesive composition of the present invention is preferably a polyurethane adhesive. Polyurethane adhesives are formed when the polymer component is a polyol and, therefore, the nucleophilic groups are hydroxy groups. However, it is not excluded that the adhesive composition of the present invention may be formed from an amine-terminated polymer (which reacts with the isocyanate component to form a urea bond) or a carboxy-terminated polymer (which reacts with the isocyanate component to form an amide bond).

[0042] Preferred polyols contain an average of 3 or more hydroxy groups per molecule, preferably an average of 3 to 5 hydroxy groups per molecule.

[0043] Preferably, at least 50 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, at least 60 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, at least 70 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, at least 80 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, or at least 90 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups.

[0044] More preferably, at least 50 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups, at least 60 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups, at least 70 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups, at least 80 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups, or at least 90 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups.

[0045] More preferably, at least 50 mole % of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups, at least 60 mole % of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups, at least 70 mole % of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups, at least 80 mole % of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups, or at least 90 mole % of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups.

[0046] Although diols are routinely used in the art to prepare polyurethane adhesives, certain diols (including diols formed from polypropylene glycol end-capped with polyethylene glycol) have been found to be more cytotoxic than similar polyols containing three or more hydroxy groups. Without being bound by theory, it is believed that the polyurethane moieties derived from the diols retain some surfactant characteristics even after reaction with crosslinking component (B).

[0047] On the other hand, it has also been found that adhesive compositions containing a high proportion of polyols containing 3 to 5 hydroxy groups retain sufficient tack even when the molar ratio of unsubstituted isocyanate functional groups in crosslinking component (B) to hydroxy groups in polyol component (A) is high. This is particularly true for adhesive compositions containing a high proportion of polyols containing 3 or 4 hydroxy groups, and even more so for adhesive compositions containing a high proportion of polyols containing 3 hydroxy groups.

[0048] The use of polyols having three or more hydroxy groups provides another source of crosslinking in the polyurethane structure. While this is somewhat beneficial, the use of polyols containing too many hydroxy groups can result in excessive crosslinking and loss of tack. Therefore, it is preferred that the polyol component primarily comprises polyols containing 3 to 5 hydroxy groups, preferably 3 or 4 hydroxy groups, and preferably 3 hydroxy groups.

[0049] The polymer component (A) is preferably selected from hydroxy-terminated polyethers (i.e., polyether polyols) and hydroxy-terminated polyesters (i.e., polyester polyols). Most preferably, the polymer component is a hydroxy-terminated polyether, more preferably a hydroxy-terminated polyether derived from ether units (monomers) containing from 2 to 10 carbon atoms, preferably from 2 to 6 carbon atoms, more preferably from 2 to 4 carbon atoms. In particular, preferred hydroxy-terminated polyethers contain repeat units derived from ethylene oxide and / or propylene oxide.

[0050] Suitable hydroxy-terminated polyethers can be obtained by alkoxylation of a starter molecule having the required number of nucleophilic groups. Preferred hydroxy-terminated polyethers include alkoxylated derivatives of compounds containing 3 to 5 hydroxy groups, or mixtures thereof. For example, suitable compounds containing 3 to 5 hydroxy groups that can be used as starter molecules to form polyethers by alkoxylation include glycerol, trimethylolpropane, erythritol, pentaerythritol, pentane-1,2,4,5-tetrol, dextrose, and mixtures thereof.

[0051] Preferred alkoxylated derivatives are ethoxylated, propoxylated, or ethoxylated-copropoxylated derivatives. Optionally, the hydroxy-terminated polyether may be an ethylene oxide-capped propoxylated derivative of a compound containing 3 to 5 hydroxy groups, or a mixture thereof, including the above. More preferably, the hydroxy-terminated polyether may be selected from ethoxylated derivatives of glycerol or trimethylolpropane, or ethylene oxide-capped propoxylated derivatives of glycerol or trimethylolpropane. Ethylene oxide capping is preferred because the less steric hindrance of the terminal hydroxy groups promotes faster reaction with the isocyanate groups of crosslinking component (B).

[0052] The polymer component (A) preferably has a weight average molecular weight (as measured by GPC) in the range of 1,000 to 50,000 daltons, preferably in the range of 1,000 to 20,000 daltons, preferably in the range of 1,500 to 10,000 daltons. The polymer component preferably has an equivalent weight per nucleophilic functional group containing an active hydrogen atom (per hydroxy group when the polymer component is a polyol) of 200 to 5,000, preferably 500 to 2,500, preferably 1,000 to 2,000.

[0053] X preferably represents a number having a value of at least 2.2, preferably at least 2.4, preferably at least 2.6, preferably at least 2.8, preferably at least 3, preferably at least 3.2. In particular, it is preferred that at least a portion of the polymer molecules in the polymer component (A) have three or more nucleophilic functional groups. Polymer molecules having three or more nucleophilic functional groups with active hydrogen atoms can introduce additional crosslinks into the polymer network of the polyurethane adhesive, which contributes to improving adhesive performance.

[0054] The value of X represents the nominal functionality of the polymer component. If the polymer component is formed from a single starter molecule, the nominal functionality of the polymer is equal to the functionality of the starter molecule (e.g., if trimethylolpropane is used as the starter molecule, it has a nominal functionality of 3). The nominal functionality can also be calculated as follows:

[0055]

number

[0056] Crosslinking component (B) The crosslinking component (B) of the adhesive composition of the present invention is obtained by reacting the polyisocyanate component (i) with at least one of: (ii) a compound containing a functional group curable by free radical polymerization and also containing a nucleophilic functional group having an active hydrogen atom; and / or (iii) a compound containing a nucleophilic functional group having an active hydrogen atom but not containing a functional group curable by free radical polymerization.

[0057] When polyisocyanate component (i) is reacted with compound (ii), the functional groups curable by free radical polymerization provide the adhesive composition with switching capability. Optionally, polyisocyanate component (i) may also be reacted with compound (iii). Further reacting polyisocyanate component (i) with compound (iii) does not contribute to the switching capability of the adhesive, but allows for further control of the degree of substitution of polyisocyanate component (i), regardless of the content of curable moieties in the adhesive.

[0058] If polyisocyanate component (i) is reacted only with compound (iii) and compound (ii) is omitted, the resulting adhesive is not switchable via the curing reaction. However, the polyurethane adhesive is nevertheless useful for medical applications due to the low cytotoxicity achieved by the present invention and the gentle behavior of the gel adhesive when peeled from the skin.

[0059] The total degree of substitution of polyisocyanate component (i) with compounds (ii) and / or (iii) is 0.2 to 0.7. At very low degrees of substitution, crosslinking component (B) contains a higher relative amount of polyisocyanate, either unsubstituted or monosubstituted. This results in tighter crosslinking of the polyol component, with more polymer end groups attached to the nodes, e.g., three or more polymer end groups attached. This has been found to result in adhesives with insufficient peel strength at the high isocyanate index required to obtain low cytotoxicity. Although effective adhesives can be obtained even with very high degrees of substitution of polyisocyanate component (i), such compositions require a higher total amount of polyisocyanate to ensure that sufficient free isocyanate groups are still available to crosslink polyol component (A). This may be undesirable for cost reasons. For example, particularly good adhesive performance is found when the total degree of substitution of polyisocyanate component (i) by compounds (ii) and / or (iii), if present, is in the range of 0.25 to 0.65, preferably in the range of 0.3 to 0.6.

[0060] Polyisocyanate component (i) The polyisocyanate component (i) has an average of 1.8 to 6 isocyanate functional groups per molecule. Preferably, the average number of isocyanate functional groups per molecule is in the range of 2 to 4, preferably in the range of 2.1 to 3.6, preferably in the range of 2.1 to 3.5, preferably in the range of 2.2 to 3.4, preferably in the range of 2.5 to 3.4. The term average is used herein to refer to an average value based on numbers, as follows:

[0061]

number

[0062] The polyisocyanate component (i) may, in principle, be selected from any polyisocyanate compound known in the art for producing polyisocyanates, as well as mixtures thereof. For example, the polyisocyanate component (i) may comprise one or more polyisocyanate compounds selected from the group of polyisocyanates having 2 to 10 isocyanate functional groups per molecule and mixtures thereof, so long as the average number of isocyanate functional groups per molecule is within the range of 1.8 to 6. Preferably, the polyisocyanate component (i) comprises one or more polyisocyanate compounds, the polyisocyanate component having an average of 2 to 4 isocyanate functional groups per molecule, preferably an average of 2.1 to 3.6 isocyanate functional groups per molecule, preferably an average of 2.1 to 3.5 isocyanate functional groups per molecule, preferably an average of 2.2 to 3.4 isocyanate functional groups per molecule, preferably an average of 2.5 to 3.4 isocyanate functional groups per molecule.

[0063] Optionally, the polyisocyanate component (i) may comprise a mixture of a diisocyanate and at least one polyisocyanate having an average of at least three isocyanate functional groups per molecule. It has been observed that mixtures of diisocyanates with other polyisocyanates result in adhesives that are more resistant to humidity. This is beneficial in medical applications where the adhesive must adhere to the skin, which may be subject to sweat secretion.

[0064] Examples of suitable polyisocyanates include diisocyanates of the formula OCN-R-NCO, where R independently represents a linear, branched, or cyclic alkylene group having 2 to 15 carbon atoms or an arylene group having 6 to 20 carbon atoms. Examples of diisocyanates include hexamethylene diisocyanate, isophorone diisocyanate, toluene 2,4-diisocyanate, 4,4'-methylenebis(phenylisocyanate), and 4,4'-methylenebis(cyclohexylisocyanate). Further suitable polyisocyanates include polymers (e.g., dimers, trimers, tetramers, etc.) based on diisocyanates.

[0065] Preferred polyisocyanates are trimerized diisocyanates of the formula D(R-NCO), where D represents a ring structure selected from isocyanurates and iminooxadiazinediones, or a branched structure selected from biurets and allophanates, and mixtures thereof, and each R independently represents a linear, branched, or cyclic alkylene group having 2 to 15 carbon atoms, or an arylene group having 6 to 20 carbon atoms. A particularly preferred polyisocyanate in this class is trimerized hexamethylene diisocyanate.

[0066] Compound (ii) The crosslinking component (B) can be obtained by reacting the polyisocyanate component (i) with at least one compound (ii) containing a functional group curable by free radical polymerization and further containing a nucleophilic functional group having an active hydrogen atom.

[0067] As used herein, the term "nucleophilic functional group having an active hydrogen atom" refers to a functional group that can undergo an addition reaction with an isocyanate group to form an adduct. For example, the nucleophilic functional group having an active hydrogen atom may be -OH, -COOH, -NH, -SH, etc. Preferably, the nucleophilic functional group having an active hydrogen atom is a hydroxy group (-OH). Preferably, the nucleophilic functional group having an active hydrogen atom is a hydroxy group bonded to a primary carbon atom (i.e., a group of the formula -CHOH). The nucleophilic hydroxy group can readily react with the isocyanate group of the polyisocyanate component (i), and hydroxy-containing compounds having curable moieties are readily available in the art. Preferably, at least one compound (ii) contains a single nucleophilic functional group having an active hydrogen atom.

[0068] At least one compound (ii) preferably contains an olefin moiety as a functional group curable by free radical polymerization. At least one compound (ii) may be a single compound or a mixture of different compounds, each containing an olefin moiety as a functional group curable by free radical polymerization. Olefin moieties (e.g., acrylates and methacrylates) tend to have high yields in polymerization reactions and are therefore good curable groups for achieving effective switching performance through a free radical-initiated curing process.

[0069] Preferably, at least one compound (ii) comprises an olefinic moiety as the functional group curable by free radical polymerization and a hydroxy group as the nucleophilic functional group having an active hydrogen atom.

[0070] In the broadest sense, any unsaturated compound that is curable by free radical polymerization and further contains a nucleophilic functional group with an active hydrogen atom can be used as compound (ii). Examples of suitable compounds include hydroxy-substituted acrylate esters and hydroxy-substituted methacrylate esters, and mixtures thereof. Preferably, at least one compound (ii) is a hydroxy-substituted -(C2-C20 ) Alkyl methacrylate ester, hydroxy-substituted -(C2-C 20 ) alkyl acrylate esters, polyalkoxylated monomethacrylate esters having 2 to 10 ether functional groups, polyalkoxylated monoacrylate esters having 2 to 10 ether functional groups, and mixtures thereof. More preferably, the at least one compound (ii) is selected from hydroxy-substituted -(C2-C6) alkyl methacrylate esters.

[0071] For example, compound (ii) may be selected from 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, polypropylene glycol monomethacrylate, and polypropylene glycol monoacrylate. Preferred compounds (ii) are 2-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, and mixtures thereof.

[0072] At least one compound (ii) may be a single compound or a mixture of compounds, each of which has a functional group curable by free radical polymerization and a nucleophilic functional group having an active hydrogen atom. When compound (ii) is a mixture of compounds, each compound preferably contains the same type of curable functional group, and more preferably each compound contains an olefin group. For example, compound (ii) may be a mixture of 2-hydroxypropyl methacrylate and isomeric hydroxyisopropyl methacrylate.

[0073] Other examples of hydroxy-containing acrylates include hydroxy (CH2) esters where n is 4 to 8. n Methacrylic acid ester, hydroxyethyl methacrylate caprolactone ester (caprolactone 2-(methacryloyloxy)ethyl ester), 3-(acryloyloxy)-2-hydroxypropyl methacrylate, and glycerol dimethacrylate.

[0074] Compound (ii) can optionally be used in combination with compound (iii). As described above, the total degree of substitution of polyisocyanate component (i) with compounds (ii) and (iii) is in the range of 0.1 to 0.7, preferably in the range of 0.15 to 0.65, more preferably in the range of 0.2 to 0.6, more preferably in the range of 0.25 to 0.6, and more preferably in the range of 0.3 to 0.6.

[0075] The degree of substitution of polyisocyanate component (i) with compound (ii) is preferably in the range of 0.05 to 0.5, 0.05 to 0.45, 0.05 to 0.4, 0.8 to 0.35, 0.8 to 0.3, 0.1 to 0.25, 0.1 to 0.2, or 0.12 to 0.18. The amount of compound (iii), if any, can be selected to achieve the above total degree of substitution. If the degree of substitution of polyisocyanate component (i) with compound (ii) is too low, the relative amount of curable groups will be low, which may reduce the switching performance of the adhesive upon curing. However, much higher levels of curable groups exceed the amount required for effective switching, thus increasing the cost of producing the adhesive without any substantial performance advantage.

[0076] Compound (iii) The crosslinking component (B) may be obtained by reacting the polyisocyanate component (i) with both the compound (ii) and the compound (iii).

[0077] As mentioned above, partial substitution of polyisocyanate component (i) is desirable to obtain a distribution of different isocyanate-containing compounds in crosslinking component (B). However, achieving the required degree of substitution of polyisocyanate component (i) with compound (ii) alone tends to result in an adhesive containing far more curable groups than necessary to obtain good switching performance. To avoid premature switching, excessive amounts of curable groups may require careful handling during the manufacture of adhesives and adhesive-containing products. Excessive substitution of polyisocyanate component (i) with compound (ii) is also undesirable for cost and biocompatibility reasons.

[0078] One particular consequence of compositions containing a high concentration of curable groups is that shear forces in the equipment used to handle the adhesive or its precursors (e.g., pumps, flow lines, etc.) during the manufacturing process can initiate premature curing of the curable groups. This can lead to poor tack in the adhesive product and, in some cases, can cause blockages in the manufacturing equipment. Therefore, the use of compound (iii) can alleviate these problems by allowing the required degree of substitution of polyisocyanate component (i) without introducing excessive curable groups into the adhesive composition.

[0079] In an alternative embodiment, crosslinking component (B) can be obtained by reacting polyisocyanate component (i) with compound (iii), where compound (ii) is omitted, in which case compound (iii) alone provides partial substitution for polyisocyanate component (i) in the absence of a curable component.

[0080] If compound (ii) is omitted, the total degree of substitution of polyisocyanate component (i) is equal to the degree of substitution of polyisocyanate component (i) with compound (iii), and therefore is in the range of 0.2 to 0.7, preferably in the range of 0.25 to 0.65, more preferably in the range of 0.3 to 0.6, more preferably in the range of 0.35 to 0.6, and more preferably in the range of 0.4 to 0.6.

[0081] At least one compound (iii) contains a nucleophilic functional group having an active hydrogen atom but does not contain a functional group curable by free radical polymerization. At least one compound (iii) may be a single compound or a mixture of different compounds, none of which contains a functional group curable by free radical polymerization.

[0082] At least one compound (iii) is a linear, branched, or cyclic C1-C 30 Aliphatic alcohols, preferably linear, branched, or cyclic C1-C 18 Aliphatic alcohols, more preferably linear, branched or cyclic C1-C 12 Preferably, at least one compound (iii) is selected from aliphatic alcohols. Preferably, at least one compound (iii) is a branched C3-C 12 Aliphatic alcohols or branched C6-C 18 The polyisocyanate component (i) is selected from aliphatic alcohols. An example of a suitable compound is 2-ethyl-1-hexanol. This type of compound occupies one or more isocyanate bond sites so as to obtain the desired distribution of reaction products from the reaction of the polyisocyanate component (i) with the compound (iii) and, optionally, the compound (ii).

[0083] However, an additional benefit of including compound (iii) is that the aliphatic carbon chain adds a degree of fattiness to the adhesive composition. This reduces the water solubility of the adhesive as a whole, and in particular reduces the ability of any components of the adhesive with relatively low molecular weight to penetrate the skin. Thus, compound (iii) also reduces the cytotoxicity of the adhesive. Furthermore, the aliphatic carbon chain acts as a plasticizer in the adhesive, reducing interactions between polymer chains. As a result, the adhesive becomes softer, cheaper, and easier to produce.

[0084] The at least one compound (iii) also allows other functionalities to be incorporated into the adhesive composition without affecting initial peel strength or switching performance. Molecules with these functionalities would otherwise be incorporated into the adhesive polyurethane composition as small molecules. Therefore, by adding them to the polyurethane network, the adhesive becomes less cytotoxic. For example, the at least one compound (iii) may comprise or consist of one or more photoinitiators having nucleophilic functional groups with active hydrogen atoms, e.g., hydroxyl groups, for bonding to the polyisocyanate component (i). For purposes of this invention, a photoinitiator is considered a molecule that initiates a curing reaction but is not itself curable. Therefore, a photoinitiator that bonds to a polyisocyanate is considered to be a compound (iii) that does not contain functional groups curable by free radical polymerization.

[0085] Other examples of compounds that can be incorporated into the adhesive composition of the present invention as compound (iii) include biocides and catalysts.

[0086] Typically, at least one compound (iii) contains a single nucleophilic group having an active hydrogen atom, but it is not excluded that at least one compound (iii) may contain two or more nucleophilic functional groups having active hydrogen atoms, in which case compound (iii) may link two polyisocyanate molecules together.

[0087] adhesive composition The relative amounts of polymer component (A) and crosslinking component (B) are defined herein by reference to the molar ratio of unsubstituted isocyanate groups in crosslinking component (B) to available nucleophilic groups in polymer component (A). As noted above, it has been found that the cytotoxicity of an adhesive is reduced when the molar ratio of unsubstituted isocyanate groups in crosslinking component (B) to nucleophilic groups in polymer component (A) is at least 0.8.

[0088] Preferably, the molar ratio of unsubstituted isocyanate groups in crosslinking component (B) to nucleophilic groups having an active hydrogen atom in polymer component (A) is at least 0.81, at least 0.82, at least 0.83, at least 0.84, at least 0.85, at least 0.86, at least 0.87, at least 0.88, at least 0.89, at least 0.90, at least 0.91, at least 0.92, at least 0.93, at least 0.94, or at least 0.95.

[0089] When compound (ii) is used in the reaction to obtain crosslinking component (B), the adhesive polyurethane preferably contains 0.05 to 1 meq / g, preferably 0.06 to 0.5 meq / g, preferably 0.08 to 0.4 meq / g, preferably 0.1 to 0.3 meq / g, preferably 0.12 to 0.25 meq / g, preferably 0.15 to 0.2 meq / g of functional groups curable by free radical polymerization. As noted above, higher levels of curable groups, while viable, offer little benefit in switching performance and increase the cost of producing the adhesive without any substantial performance advantage.

[0090] The reactants used to form the adhesive composition of the present invention are preferably substantially free of water. Water may be present, for example, as a minor impurity in the polyol component (A) or in compounds (ii) and (iii). Water reacts with the isocyanate groups of the crosslinking component (B), thus reducing the number of unsubstituted isocyanate functional groups in the crosslinking component (B) available to react with the nucleophilic functional groups in the polymer component (A). For the avoidance of doubt, when referring herein to the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to the nucleophilic functional groups having an active hydrogen atom in the polymer component (A), the degree of substitution of the polyisocyanate component (i) with water is taken into account, and the content of unsubstituted isocyanate functional groups is adjusted accordingly.

[0091] Preferably, the maximum degree of substitution of polyisocyanate component (i) with water is not more than 0.1, preferably not more than 0.08, preferably not more than 0.06, preferably not more than 0.05, preferably not more than 0.04. Considering that water is a difunctional molecule, the total degree of substitution of polyisocyanate component (i) with water is calculated as follows:

[0092]

number

[0093] The photoinitiator may be mixed into the adhesive composition and / or attached to the polymer chains of the adhesive composition. Optionally, a photoinitiator may be used as compound (iii), so long as the photoinitiator has a nucleophilic functional group suitable for bonding to the polyisocyanate component and the photoinitiator function is not thereby hindered.

[0094] The photoinitiator may be any species capable of generating radical species under mild conditions, such as UV or visible light, to promote free-radical initiated polymerization of the curable functional groups of compound (ii).

[0095] Preferably, the photoinitiator is responsive to UV radiation having a wavelength in the range of 200 to 400 nm, preferably UVA radiation (315 to 400 nm). UVA is particularly preferred for medical applications and other applications requiring exposure of humans or animals to UV radiation. The 200 to 400 nm range is referred to herein as "long wavelength UV."

[0096] Photoinitiators can alternatively generate radical species upon exposure to visible light, but products that are curable by exposure to visible light require careful handling to avoid premature switching of the adhesive and / or require additional visible light blocking materials to be incorporated into the product, which must be removed from the product in a timely manner when switching is desired.

[0097] The UV-sensitive photoinitiator may be selected from any of the conventional photoinitiators known in the art. For example, UV-sensitive photoinitiators include benzoin and derivatives (e.g., ethyl, isopropyl, or isobutyl ether of benzoin, etc.); benzophenone and derivatives (e.g., 4-phenylbenzophenone, etc.); acetophenone and 4-phenoxyacetophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone; 2-dimethylamino-2-(4-methyl -benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one; 2-ethylanthraquinone; benzil dimethyl ketal; 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methylpropanone; 2-hydroxy-1-[4-[4-(2-hydroxy-2-methylpropionyl)benzyl)-phenyl)-2-methylpropan-1-one; 2-hydroxy-2-methylpropiophenone; and ethyl 4-(dimethylamino)benzoate.

[0098] Free radical initiators suitable for visible light activation include titanocene photoinitiators, dye / co-initiator systems such as thionine / triethanolamine, dye / peroxide systems, and 1,2-diketone / co-initiator systems such as camphorquinone / tertiary amine. Examples of visible light photoinitiators are phenanthrenequinone, titanocene, and bis(2,4,6-trimethyl-benzoyl)-phenylphosphine oxide.

[0099] solvent The adhesive composition may further comprise a solvent. The solvent must be an aprotic solvent so as not to react with the isocyanate groups of the polyisocyanate component (i). Preferably, the solvent has low toxicity, and preferably, the solvent is non-toxic. An example of a preferred solvent is ethyl acetate.

[0100] stabilizers If the adhesive composition contains curable functional groups, it may also contain a stabilizer. As used herein, the term "stabilizer" refers to a substance added to the adhesive composition to scavenge free radicals to prevent premature reaction of the curable functional groups in the adhesive during manufacturing and / or storage of the adhesive composition. These substances are well known in the field of curable materials and are sometimes called antioxidants.

[0101] Examples of suitable stabilizers include 1-piperidinyloxy-4,4'-[1,10-dioxo-1,10-decanediyl)bis(oxy)]bis[2,2,6,6-tetramethyl] and phenol derivatives such as methoxyphenol, di-tert-butyl-4-methylphenol, and pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate).

[0102] Optional Components If the adhesive composition contains a curable functional group, it may also contain a photosensitizer. Because sensitizing species often absorb energy in a different part of the spectrum than the photoinitiator, more efficient use of the light source may be achieved by incorporating a sensitizer into the composition. Many photosensitizers are complex organic molecules that absorb in the long-wavelength UV and / or visible parts of the spectrum.

[0103] The adhesive composition can also incorporate scattering particles to enhance the irradiation effect of the adhesive mixture by scattering UV or visible light irradiating through the thickness of the adhesive mixture. Preferably, the light-scattering particles are inorganic compounds such as silica powder, alumina powder, silica-alumina powder, or mica powder, and have a particle size of 10 nm or more, typically up to 1 μm.

[0104] For switchable adhesive compositions, the reactivity of the composition can be increased by increasing the concentration (meq / g) of curable groups in the adhesive, by using compounds (ii) with two or more curable groups, and / or by using more reactive functionality in the adhesive, for example, by partially or completely replacing methacrylate with acrylate (acrylate is more reactive but also slightly more toxic).

[0105] The intermolecular interactions of the adhesive before switching, and therefore the viscosity of the adhesive, can be reduced by using bulky groups (e.g., by adding methyl groups or branching the polyol component (A)) and / or by introducing asymmetry or greater hydrophobicity into the crosslinking component (B). This may be achieved by using a polyisocyanate component (i) with bulky groups, for example, by replacing hexamethylene diisocyanate with trimethylhexamethylene diisocyanate, isocyanurate with iminooxadiazinedione, butanediol with methylpentanediol, or polyethylene glycol with polypropylene glycol. Alternatively, this may also be achieved by using at least one compound (iii) in the crosslinking component (B), where at least one compound (iii) contains a bulky group.

[0106] The adhesive compositions of the present invention exhibit a reduction in peel force after switching of at least 30%, preferably 50 to 99%, preferably 70 to 99%, when measured according to the method described below.

[0107] According to a first aspect of the present invention, there is further provided an adhesive composition according to the following aspects 1-1 to 1-20.

[0108] Aspect 1-1: An adhesive polyurethane composition according to a first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.2; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing from 3 to 5 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2 to 4 isocyanate functional groups per molecule; (v) compound (ii) is present and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.05 to 0.5, preferably from 0.05 to 0.45; (vi) the total degree of substitution of polyisocyanate component (i) with compound (ii) and optional compound (iii) is from 0.25 to 0.65; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.82;

[0109] Aspect 1-2: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.4; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.1 to 3.6 isocyanate functional groups per molecule; (v) compound (ii) is present and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.05 to 0.4, preferably from 0.08 to 0.35; (vi) the total degree of substitution of polyisocyanate component (i) with compound (ii) and optional compound (iii) is from 0.3 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.86;

[0110] Aspects 1-3: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.6; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.2 to 3.4 isocyanate functional groups per molecule; (v) compound (ii) is present and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.08 to 0.3, preferably from 0.1 to 0.25; (vi) the total degree of substitution of polyisocyanate component (i) with compound (ii) and optional compound (iii) is from 0.35 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.9;

[0111] Aspects 1-4: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.8; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.5 to 3.4 isocyanate functional groups per molecule; (v) compound (ii) is present and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.1 to 0.2, preferably from 0.12 to 0.18; (vi) the total degree of substitution of polyisocyanate component (i) with compound (ii) and optional compound (iii) is from 0.4 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.92;

[0112] Aspects 1-5: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.2; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing from 3 to 5 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2 to 4 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.05 to 0.5, preferably from 0.05 to 0.45; (vi) the total degree of substitution of polyisocyanate component (i) with compound (ii) and compound (iii) is from 0.25 to 0.65; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.82;

[0113] Aspects 1-6: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.4; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.1 to 3.6 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.05 to 0.4, preferably from 0.08 to 0.35; (vi) the total degree of substitution of polyisocyanate component (i) with compound (ii) and compound (iii) is from 0.3 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.86;

[0114] Aspects 1-7: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.6; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.2 to 3.4 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.08 to 0.3, preferably from 0.1 to 0.25; (vi) the total degree of substitution of polyisocyanate component (i) with compound (ii) and compound (iii) is from 0.35 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.9;

[0115] Aspects 1-8: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.8; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.5 to 3.4 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.1 to 0.2, preferably from 0.12 to 0.18; (vi) the total degree of substitution of the polyisocyanate component (i) with compound (ii) and compound (iii) is from 0.4 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.92;

[0116] Aspects 1-9: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.2; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,000 to 20,000 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing from 3 to 5 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2 to 4 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.05 to 0.5, preferably from 0.05 to 0.45; (vi) the total degree of substitution of the polyisocyanate component (i) with compound (ii) and compound (iii) is from 0.25 to 0.65; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.82; (viii) At least one compound (ii) is a hydroxy-substituted -(C-C 20 ) alkyl-methacrylate esters and hydroxy-substituted-(C2-C 20 ) alkyl-acrylate esters; and (ix) At least one compound (iii) is a C1-C 30 The adhesive polyurethane composition is selected from aliphatic alcohols.

[0117] Aspects 1-10: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.4; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,000 to 20,000 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.1 to 3.6 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.05 to 0.4, preferably from 0.08 to 0.35; (vi) the total degree of substitution of the polyisocyanate component (i) with compound (ii) and compound (iii) is 0.3 to 0.6; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.86; (viii) at least one compound (ii) is selected from hydroxy-substituted (C2-C6) alkyl-methacrylate esters; and (ix) At least one compound (iii) is a linear, branched, or cyclic C1-C 18 The adhesive polyurethane composition is selected from aliphatic alcohols.

[0118] Aspects 1-11: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.6; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,500 to 10,000 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.2 to 3.4 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.08 to 0.3, preferably from 0.1 to 0.25; (vi) the total degree of substitution of the polyisocyanate component (i) with compound (ii) and compound (iii) is from 0.35 to 0.6; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.9; (viii) the at least one compound (ii) is selected from 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, polypropylene glycol monomethacrylate, and polypropylene glycol monoacrylate; and (ix) At least one compound (iii) is a linear, branched, or cyclic C 1- C 12 The adhesive polyurethane composition is selected from aliphatic alcohols.

[0119] Aspects 1-12: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.8; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,000 to 2,500 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.5 to 3.4 isocyanate functional groups per molecule; (v) compounds (ii) and (iii) are present, and the degree of substitution of polyisocyanate component (i) with compound (ii) is in the range of from 0.1 to 0.2, preferably from 0.12 to 0.18; (vi) the total degree of substitution of the polyisocyanate component (i) with compound (ii) and compound (iii) is 0.4 to 0.6; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.92; (viii) at least one compound (ii) is selected from 2-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, and mixtures thereof; and (ix) At least one compound (iii) is a branched C 3- C 12 The adhesive polyurethane composition is selected from aliphatic alcohols.

[0120] Aspects 1-13: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.2; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing from 3 to 5 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2 to 4 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of polyisocyanate component (i) with compound (iii) is from 0.25 to 0.65; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.82;

[0121] Aspects 1-14: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.4; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.1 to 3.6 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of polyisocyanate component (i) with compound (iii) is from 0.3 to 0.6; (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.86;

[0122] Aspects 1-15: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.6; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.2 to 3.4 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of polyisocyanate component (i) with compound (iii) is from 0.35 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.9;

[0123] Aspects 1-16: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.8; (ii) polymer component (A) is a polyol, preferably a polyether polyol, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.5 to 3.4 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of polyisocyanate component (i) with compound (iii) is from 0.4 to 0.6; and (vii) an adhesive polyurethane composition in which the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.92;

[0124] Aspects 1-17: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.2; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,000 to 20,000 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing from 3 to 5 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2 to 4 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of polyisocyanate component (i) with compound (iii) is from 0.25 to 0.65; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.82; and (viii) at least one compound (iii) is C1-C 30 The adhesive polyurethane composition is selected from the fatty alcohols of the formula:

[0125] Aspects 1-18: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.4; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,000 to 20,000 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing 3 or 4 hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.1 to 3.6 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of polyisocyanate component (i) with compound (iii) is from 0.3 to 0.6; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.86; and (viii) At least one compound (iii) is a linear, branched, or cyclic C1-C 18 The adhesive polyurethane composition is selected from aliphatic alcohols.

[0126] Aspects 1-19: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.6; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,500 to 10,000 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.2 to 3.4 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of polyisocyanate component (i) with compound (iii) is from 0.35 to 0.6; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.9; and (viii) At least one compound (iii) is a linear, branched, or cyclic C1-C 12 The adhesive polyurethane composition is selected from aliphatic alcohols.

[0127] Aspects 1-20: An adhesive polyurethane composition according to the first aspect of the present invention, comprising: (i) X represents a number having a value of at least 2.8; (ii) polymer component (A) is a polyether polyol having a weight average molecular weight in the range of 1,000 to 2,500 daltons, preferably a polyether polyol containing repeat units derived from ethylene oxide and / or propylene oxide; (iii) at least 60 mole percent of the hydroxy groups in the polyol are present in polyol molecules containing three hydroxy groups; (iv) the polyisocyanate component (i) has an average of 2.5 to 3.4 isocyanate functional groups per molecule; (v) compound (ii) is absent; (vi) the total degree of substitution of the polyisocyanate component (i) with compound (ii) and compound (iii) is 0.4 to 0.6; (vii) the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to hydroxy groups in the polyol component (A) is at least 0.92; and (viii) At least one compound (iii) is a branched C3-C 12 The adhesive polyurethane composition is selected from aliphatic alcohols.

[0128] Any preferred / optional feature disclosed herein with respect to a first aspect of the invention that falls within the scope of aspects 1-1 to 1-20 above will be understood to be a preferred / optional feature of aspects 1-1 to 1-20. Similarly, any features of dependent claims that fall within the scope of aspects 1-1 to 1-20 above will be interpreted as if those claims also recite aspects 1-1 to 1-20.

[0129] Method for preparing an adhesive composition According to a second aspect of the present invention, there is provided a method of preparing an adhesive composition, the method comprising: (a) To form the cross-linking component (B), (i) a polyisocyanate component having an average of 1.8 to 6 isocyanate functional groups per molecule, (ii) at least one compound containing a functional group curable by free radical polymerization and further containing a nucleophilic functional group having an active hydrogen atom; and (iii) at least one compound containing a nucleophilic functional group having an active hydrogen atom and no functional group curable by free radical polymerization; wherein the total degree of substitution of polyisocyanate component (i) with compounds (ii) and / or (iii) is in the range of 0.2 to 0.7; (b) a second step of combining the cross-linking component (B) formed in step (a) with a polymer component (A), the polymer component (A) having a weight average molecular weight in the range of 1,000 to 100,000 daltons and having an average of X nucleophilic functional groups with active hydrogen atoms per molecule, where X represents a number having a value of at least 2; Including, The amounts of crosslinking component (B) and polyol component (A) are selected so that the molar ratio of unsubstituted isocyanate functional groups in crosslinking component (B) to nucleophilic functional groups having active hydrogen atoms in polymer component (A) is at least 0.8.

[0130] The method of the second aspect of the invention can be used to produce the adhesive composition of the first aspect of the invention. Accordingly, any feature described as optional or preferred with reference to the first aspect of the invention should be understood to also constitute an optional or preferred feature with respect to the identities, amounts, and proportions of the corresponding components used in the method of the second aspect of the invention. For example, the method of the second aspect of the invention can be used to produce the adhesive composition of any of aspects 1-1 to 1-18 above.

[0131] Step (a) and / or step (b) of the method for preparing a pressure-sensitive adhesive polyurethane composition may be carried out in the presence of a catalyst. Suitable catalysts include dibutyltin dilaurate, zirconium(IV) acetylacetonate, dibutyltin 2-ethylhexanoate, zinc(II) 2-ethyl-1-hexanoate, and tertiary amines.

[0132] Step (a) and / or step (b) may be carried out in the presence of a solvent. Suitable solvents are aprotic solvents such as ethyl acetate, toluene, and tetrahydrofuran.

[0133] Preferably, a photoinitiator is combined with the product of step (a) or with the polyol component prior to step (b). Most preferably, a photoinitiator is combined with the polyol component prior to step (b).

[0134] Adhesive medical devices According to a third aspect of the present invention, there is provided an adhesive medical device comprising a layer of an adhesive composition according to any one of claims 1 to 28 disposed on a first carrier film, and a release liner disposed over the layer of adhesive.

[0135] The adhesive medical device may include a product selected from the group including adhesive dressings including absorbent wound pads, surgical incise drapes, bacterial barriers for covering wounds, and skin closure devices for closing wound edges together.

[0136] Where the medical product comprises a switchable adhesive, suitably the first carrier film of the medical device may be translucent to UV and / or visible light, and optionally a removable light occlusive layer is laminated to the first carrier film on the surface opposite the adhesive composition.

[0137] Exemplary materials for the carrier film to carry the switchable adhesive composition layer include polyethylene, polypropylene, polyurethane, ethylene / propylene copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl acetate copolymer, silicone elastomer, polydimethylsiloxane, neoprene rubber, polyisobutylene, polyacrylate, chlorinated polyethylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, crosslinked polymethacrylate polymer (hydrogel), polyvinylidene chloride, poly(ethylene terephthalate), butyl rubber, epichlorohydrin rubber, ethylene vinyl alcohol copolymer, ethylene vinyl acetate ... Examples of suitable polymeric materials include polyethylene-vinyloxyethanol copolymers; silicone copolymers such as polysiloxane-polycarbonate copolymers, polysiloxane-polyethylene oxide copolymers, polysiloxane-polymethacrylate copolymers, polysiloxane-alkylene copolymers (e.g., polysiloxane-ethylene copolymers), and polysiloxane-alkylenesilane copolymers (e.g., polysiloxane-ethylenesilane copolymers); cellulose polymers such as methyl or ethyl cellulose, hydroxypropyl methylcellulose, and cellulose esters; polycarbonates; and polytetrafluoroethylene. More preferred are medical polyether or polyester polyurethanes, thermoplastic polyester elastomers, perforated polyethylene, polypropylene, and PET films, as well as medical woven or nonwoven fabric materials.

[0138] Adhesive wound dressings typically consist of an absorbent pad for absorbing exudate from a covered wound, surrounded by an adhesive area for securing the wound pad in place on the wound. The adhesive area and wound pad are supported on a carrier film that is often flesh-colored or may have an attractive design on its visible surface. The switchable adhesive composition according to the present invention is an ideal candidate for use as the adhesive in the adhesive area around the wound pad of an adhesive wound dressing.

[0139] Adhesive wound dressings are often applied at home by general users, not necessarily by medical professionals. Because few homes have access to suitable UV irradiation equipment, home adhesive wound dressings preferably contain an adhesive that can be cured by visible light. In some cases, switchable adhesive wound dressings preferably contain an adhesive that can be cured by UV light, so that the timing of dressing removal is controlled by medical professionals. If the adhesive is curable by UV light, a removable light-blocking layer may not be necessary.

[0140] Adhesive wound dressings intended for home use will preferably include a light-shielding layer to prevent premature switching of the switchable adhesive composition. A first light-shielding layer is placed on the carrier film on the side opposite the adhesive and remains in place until the user desires to remove the adhesive wound dressing. At this point, the first light-shielding layer is removed, exposing the underlying switchable adhesive composition to visible light, resulting in the adhesive composition switching from a tacky state to a non-tacky or low-tacky state. Optionally, a second light-shielding layer may form part of a release liner placed on the adhesive side of the dressing. This second light-shielding layer is removed just before the adhesive wound dressing is applied to the wound. If the adhesive wound dressing is provided in a light-tight package, the second light-shielding layer may not be necessary.

[0141] If the adhesive wound dressing contains an adhesive that can be cured by UV light, a light-shielding layer may not be necessary. Instead, the carrier film of the adhesive wound dressing only needs to be translucent to UV light. When it is desired to remove the adhesive wound dressing, a trained medical professional will shine a suitable UV light source on the adhesive wound dressing to initiate the curing reaction. Within a few seconds, the adhesive will lose its stickiness, and the wound dressing can be easily removed.

[0142] The release liner may be selected from any coated material with low surface energy to allow it to be easily removed from the adhesive layer. Suitable release liners include paper and plastic films provided with a silicone coating on the surface that contacts the adhesive composition.

[0143] If the adhesive wound dressing does not contain an adhesive composition having a curable moiety, i.e., if component (ii) is not used in the reaction to obtain crosslinked component (B), the use of a light-shielding layer is not necessary.

[0144] According to a fourth aspect of the present invention there is provided a method of treating a wound using an adhesive medical product described herein, the method comprising the steps of removing the release liner and applying the adhesive medical device to the wound.

[0145] Detailed Description of the Drawings An adhesive medical device using the adhesive polyurethane composition of the present invention will now be described with reference to Figures 1 to 4. The adhesive medical product in this example is an adhesive medical dressing.

[0146] 1 is a cross-sectional view through an adhesive medical dressing 100 attached to a patient's skin 20. The adhesive medical dressing 100 is a multi-layer product having the following structure: The dressing 100 includes a wound-facing absorbent layer 130 disposed beneath a protective backing layer 140. At both ends 150, the backing layer 140 is provided with an adhesive polyurethane composition 170.

[0147] Backing layer 140 is optionally provided with a light-blocking cover layer 180 that is releasably secured to backing layer 140 by a weak adhesive 190. To facilitate removal, light-blocking cover layer 180 overhangs backing layer 140 at its ends 110. If the adhesive is a switchable adhesive composition 170 and has a photoinitiator activated by UV radiation, or if the adhesive composition is not switchable, light-blocking cover layer 180 may be omitted.

[0148] 2 is a perspective view illustrating an attempt to remove a switchable adhesive dressing 100 from a patient's forearm 14 prior to switching the switchable adhesive composition containing a curable portion. Prior to switching, the adhesive composition 171 is very tacky, fairly firmly adhering the adhesive dressing 100 to the patient's skin 20. Thus, when the patient attempts to remove the dressing 100 from the forearm 14, the dressing 100 remains adhered to the skin 20 unless the dressing 100 is removed with some force.

[0149] 3 is a perspective view showing the switchable adhesive dressing being irradiated, in this example from a lamp 60, to cause curing of the curable molecules in the adhesive composition 170. The light from the lamp 60 (UV light or visible light, preferably long wavelength UV) causes a photoinitiator in the adhesive composition 170 to generate free radicals, which initiate curing of the curable molecules in the adhesive composition. Curing converts (switches) the adhesive composition 170 from its tacky state to a non-tacky or low-tacky state.

[0150] FIG. 4 is a perspective view illustrating how the patient can easily remove the adhesive dressing 100 from the forearm 14 after switching adhesive compositions without requiring excessive force. [Example]

[0151] Examples 1-2 - Crosslinking Component (B) The reaction was carried out at room temperature with stirring. Solvent B was dried using 3 Å molecular sieves. Next, the components shown below in Table 1, except for the catalyst, were added to a reagent bottle and mixed to form a homogeneous solution, after which the catalyst was added. The mixture was left overnight to complete the reaction. After GPC measurement confirmed that no unreacted hydroxypropyl methacrylate or 2-ethyl-1-hexanol remained, the isocyanate-functional acrylate oligomer was ready for use.

[0152] GPC was performed by diluting the sample with tetrahydrofuran in a ratio of 1:100 and injecting a volume of 20 μl into the injection valve of a Waters HPLC 1515 pump using tetrahydrofuran at a flow rate of 1 ml / min. The instrument was equipped with a Styragel HR1 column connected to a Waters 2414 refractive index detector.

[0153] The ingredients shown in Table 1 are as follows: A Polyisocyanate Component (i) B Solvent C catalyst D. Stabilizer E Compound (ii) F Compound (iii) G water (iv)

[0154] [Table 1] Example 3 - Preparation of Polyol Component (A) Under protection from UV light sources, all ingredients in Table 2 were placed in a sealable glass jar and mixed using a magnetic stirrer until all solid materials were dissolved.

[0155] The ingredients shown in the table are as follows: H Polyol I Photopolymerization initiator I C catalyst D. Stabilizer to prevent premature changeover during storage J Surfactants K Photopolymerization initiator II

[0156] [Table 2] Example 4 - Preparation of Polyol Component (A) Polyol component (A) was prepared in a manner similar to Example 3 using the following reagents in Table 3.

[0157] [Table 3] Examples 5-9 - Adhesive Polyurethane Compositions Examples 5 to 9 are examples of adhesive compositions according to the invention formulated to contain the crosslinking component (B) from Example 1 and the polymer component (A) from Example 3 in the amounts shown in Table 4. These compositions contain a curable compound (ii) in the crosslinking component (B), making the adhesive compositions switchable.

[0158] Under protection from UV light, both components A and B in Examples 5 through 9 were placed in a sealable glass jar and mixed for approximately 10 minutes using a magnetic stirrer until a uniform solution was formed. The resulting adhesive solution was then spread onto a flexible medical polyurethane film with a removable carrier film (Medical Film 48938) using a spreader with a 150 μm gauge. The adhesive coating was then cured in a fan-assisted oven at 130°C for 10 minutes. After this step, the adhesive coating had a thickness of approximately 70-90 μm.

[0159] [Table 4] Examples 10 to 14 - Adhesive Polyurethane Compositions Examples 10 to 14 are examples of switchable adhesive compositions according to the present invention formulated to contain the crosslinking component (B) from Example 2 and the polymer component (A) from Example 4 in the amounts shown in Table 5.

[0160] The adhesives were prepared according to the procedures described in Examples 5-9.

[0161] [Table 5] Peel force measurement The peel force before and after switching was determined for each of the adhesives in Examples 5 through 14. In preparation for the peel force measurement, a very easy release liner was transferred to the exposed side of the adhesive. The removable carrier film was then removed from the medical film and replaced with high-adhesion PET tape. The PET tape was secured to the medical film to negate the elastic effect of the medical film on the measured peel force.

[0162] Peel forces were determined after a 20 minute dwell time using an Instron 5943 test apparatus equipped with a 100 N load cell according to FINAT test method FTM1, except that stainless steel was used as the substrate surface and a peel rate of 100 mm / min and a crosshead speed of 200 mm / s were used to collect all of the required data within the time frame of a single peel force measurement.

[0163] Adhesive switching was achieved by exposing the adhesive (bonded to a steel plate) through PET tape and a medical film backing to light at approximately 50 W / m² intensity from a XeLED-Ni3UV-R4-365-E27-SS lamp with a narrow spectrum around 365 nm. Switching times for different coatings were measured as the time from the start of irradiation to the occurrence of essentially instantaneous adhesion loss during a continuous peel strength test of approximately 1.5 minutes (i.e., the adhesive was peeled for a period of time while irradiated). Peel force measurements continued under irradiation until the peel force reached a plateau value, which typically occurred 5–10 seconds after the switching time. The peel force and switching time at the plateau value were measured four times, and the average switching times and peel forces (before and after switching) are reported in Table 6.

[0164] Cytotoxicity assessment The cytotoxicity of the adhesives constituting the examples was measured according to the guidelines of ISO 10993-5 "Biological evaluation of Medical Devices, Part 5: Test for In Vitro Cytotoxicity," and the criteria for the elution test are shown in Table 6 below. To determine whether a sample passed the test, the measured viability must meet or exceed a value of 70%.

[0165] The results of the peel force measurements, along with the viability results from the cytotoxicity measurements, are shown in Table 6. Unless otherwise noted, no significant adhesion failure occurred between the steel surface of the substrate and the adhesive.

[0166] [Table 6] From Table 6 it can be seen that in both cases a reduction in peel force of about 99% is obtained and that the switched peel force does not appear to be dependent on the unswitched one.

[0167] The results of viability measurements for the adhesives in Examples 5-9 and 10-14 versus their NCO index are shown graphically in Figures 5 and 6, respectively.

[0168] FIG. 5 demonstrates the results of cytotoxicity tests on adhesives based on the triol Lupranol 2095 with different A to B component ratios.

[0169] FIG. 6 demonstrates the results of cytotoxicity tests on adhesives based on the triol Voranol CP6001 with different A to B component ratios.

[0170] As can be seen in Figures 5 and 6, there is a strong correlation between viability and NCO Index, and because the changes in the concentrations of the components involved are relatively small at the present ratios, without being bound by theory, it is believed that the increase in NCO Index viability is due to the reduction in remaining unreacted polyol hydroxy groups. A plausible reason for the toxicity of unbound polyol would be that the polyol has some surface activity, thereby disrupting cell membranes, similar to many other cleaning agents, such as ordinary soap.

[0171] Example 15 - Crosslinking Component (B) Crosslinking component (B) was prepared in a manner similar to Examples 1 and 2 using the following ingredients:

[0172] [Table 7] Examples 16 and 17 - Adhesive Polyurethane Compositions The adhesive polyurethane compositions of Examples 16 and 17 were prepared in a manner similar to Examples 5-9.

[0173] [Table 8] Peel force and viability measurements were obtained and are shown in Table 9.

[0174] [Table 9] Examples 18-20 - Crosslinking Component (B) The reaction was carried out at room temperature with stirring. Solvent B was dried using 3A (Angstrom) molecular sieves. Next, the components shown below in Table 1, except for the catalyst, were added to a reagent bottle and mixed to form a homogeneous solution, after which the catalyst was added. The mixture was left overnight to complete the reaction. After GPC measurement confirmed that no unreacted hydroxypropyl methacrylate or 2-ethyl-1-hexanol remained, the isocyanate-functional acrylate oligomer was ready for use.

[0175] GPC was performed by diluting the sample with tetrahydrofuran in a ratio of 1:100 and injecting a volume of 20 μl into the injection valve of a Waters HPLC 1515 pump using tetrahydrofuran at a flow rate of 1 ml / min. The instrument was equipped with a Styragel HR1 column connected to a Waters 2414 refractive index detector.

[0176] After ensuring that all of the hydroxy-containing material had reacted, the NCO content was determined according to ASTM standard D 2572-97 (Reapproved 2003).

[0177] The ingredients shown in Table 10 are as follows: A Polyisocyanate Component (i) B Solvent C catalyst D. Stabilizer E Compound (ii) F Compound (iii) G water (iv)

[0178] [Table 10] Example 21 - Preparation of Polyol Component (A) Under protection from UV light sources, all ingredients in Table 11 were placed in a sealable glass jar and mixed using a magnetic stirrer until all solid materials were dissolved.

[0179] The ingredients shown in Table 11 are as follows: H Polyol I Photopolymerization initiator I B Solvent C catalyst D. Stabilizer to prevent premature conversion during storage J Surfactants K Photopolymerization initiator II

[0180] [Table 11] Examples 22-24 - Adhesive Polyurethane Compositions Examples 22-24 are adhesive compositions according to the invention formulated to contain the crosslinking component (B) from Example 18 and the polymer component (A) from Example 21 in the amounts shown in Table 12. These compositions contain a curable compound (ii) in the crosslinking component (B), making the adhesive compositions switchable.

[0181] Under protection from UV light, both components A and B in Examples 22-24 were placed in a sealable glass jar and mixed for approximately 10 minutes using a magnetic stirrer until a uniform solution was formed. The resulting adhesive solution was then spread onto a flexible medical polyurethane film with a removable carrier film (Medical Film 48938) using a spreader with a 150 μm gauge. The adhesive coating was then cured in a fan-assisted oven at 130°C for 10 minutes. After this step, the adhesive coating had a thickness of approximately 70-90 μm.

[0182] [Table 12] Examples 25-27 - Adhesive Polyurethane Compositions Examples 25 to 27 are examples of switchable adhesive compositions according to the present invention formulated to include the crosslinking component (B) from Example 19 and the polymer component (A) from Example 21 in the amounts shown in Table 13.

[0183] The adhesives were prepared according to the procedures described in Examples 22-24.

[0184] [Table 13] Examples 28-29 - Adhesive Polyurethane Compositions Examples 28-29 are examples of switchable adhesive compositions according to the present invention formulated to include the crosslinking component (B) from Example 20 and the polymer component (A) from Example 21 in the amounts shown in Table 14.

[0185] The adhesives were prepared according to the procedures described in Examples 22-24.

[0186] [Table 14] Peel force measurement The peel force before and after switching was determined for each of the adhesives of Examples 22 through 29. In preparation for the peel force measurement, the release liner was transferred to the exposed side of the adhesive. The removable carrier film was then removed from the medical film and replaced with high-adhesion PET tape. The PET tape was secured to the medical film to negate the elastic effect of the medical film on the measured peel force.

[0187] Peel strength was determined according to FINAT test method FTM1 using an Instron 5943 test apparatus equipped with a 100 N load cell after a 20 minute dwell time, except that stainless steel was used as the substrate surface and a peel rate of 100 mm / min, a crosshead speed of 200 mm / s was used to collect all of the necessary data within the time frame of a single peel force measurement. The results are shown in Table 15.

[0188] [Table 15] From Table 5, as previously shown, it can be seen that a decrease in the NCO index leads to an increase in the peel force for all three series, which means that the peel force can be adjusted by the NCO index. It should also be noted that the highest peel force in each series, Examples 24, 27, and 29, represents the maximum achievable peel force value that can be reached without cohesive failure for each of the combined A and B components. Furthermore, the actual NCO index of the final adhesive is expected to be somewhat lower than that calculated, since the isocyanate functional groups in this case are also expected to react internally and with ambient humidity.

[0189] material In the above examples, the following materials were used:

[0190] [Table 16]

Claims

1. (A) a polymer component having a weight average molecular weight in the range of 1,000 to 100,000 daltons and having an average of X nucleophilic functional groups having active hydrogen atoms per molecule, where X represents a number having a value of at least 2; (B) (i) a polyisocyanate component having an average of 1.8 to 6 isocyanate functional groups per molecule, (ii) at least one compound containing a functional group curable by free radical polymerization and further containing a nucleophilic functional group having an active hydrogen atom; and (iii) at least one compound containing a nucleophilic functional group having an active hydrogen atom and no functional group curable by free radical polymerization; and a cross-linking component obtained by reacting the cross-linking component with at least one of 1. An adhesive composition comprising the reaction product of the total degree of substitution of the polyisocyanate component (i) with the compounds (ii) and (iii) is in the range of 0.1 to 0.7, and the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to nucleophilic functional groups having active hydrogen atoms in the polymer component (A) is at least 0.

8.

2. The adhesive composition of claim 1 , wherein X has a value of at least 2.2, at least 2.4, at least 2.6, at least 2.8, at least 3, or at least 3.

2.

3. 10. The adhesive composition of claim 1, wherein the polymer component is a polyol, preferably a polyol containing an average of 2.8 to 5 hydroxy groups per molecule.

4. 4. The adhesive composition of claim 3, wherein at least 50 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, at least 60 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, at least 70 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, at least 80 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups, or at least 90 mole % of the hydroxy groups in the polyol are present in polyol molecules containing 3 to 5 hydroxy groups.

5. 2. The adhesive composition of claim 1, wherein the polymer component (A) is a polyol selected from hydroxy-terminated polyethers and hydroxy-terminated polyesters.

6. 6. The adhesive composition of claim 5, wherein the hydroxy-terminated polyether is an alkoxylated derivative of a compound containing 3 to 5 hydroxy groups or a mixture thereof.

7. 7. The adhesive composition of claim 6, wherein the compound containing 3 to 5 hydroxy groups is selected from glycerol, trimethylolpropane, erythritol, pentaerythritol, pentane-1,2,4,5-tetrol, dextrose, and mixtures thereof, and preferably the alkoxylated derivative is an ethoxylated derivative, a propoxylated derivative, or an ethoxylated-copropoxylated derivative.

8. 2. The adhesive composition of claim 1, wherein the polymer component has a weight average molecular weight in the range of 1,000 to 50,000 daltons, preferably in the range of 1,000 to 20,000 daltons, preferably in the range of 1,500 to 10,000 daltons.

9. 10. The adhesive composition of claim 1, wherein the polymer component has an equivalent weight per nucleophilic functional group of 200 to 5,000, preferably 500 to 2,500, preferably 1,000 to 2,000.

10. 2. The adhesive composition of claim 1, wherein the polyisocyanate component (i) comprises an average of 2 to 4 isocyanate functional groups per molecule, preferably an average of 2.1 to 3.6 isocyanate functional groups per molecule, preferably an average of 2.1 to 3.5 isocyanate functional groups per molecule, preferably an average of 2.2 to 3.4 isocyanate functional groups per molecule, preferably an average of 2.5 to 3.4 isocyanate functional groups per molecule.

11. The polyisocyanate component (i) has the formula D(R-NCO) ３ wherein D represents a ring structure selected from isocyanurates and iminooxadiazinediones, or a branched structure selected from biurets and allophanates, and mixtures thereof; and each R independently represents a linear, branched, or cyclic alkylene group having from 2 to 15 carbon atoms, or an aryl group having from 6 to 20 carbon atoms; and preferably the trimerized diisocyanate is trimerized hexamethylene diisocyanate.

12. 2. The adhesive composition of claim 1, wherein the crosslinking component (B) is obtained by reacting the polyisocyanate component (i) with the compound (ii) and optionally with the compound (iii).

13. 13. The adhesive composition of claim 12, wherein the degree of substitution of the polyisocyanate component (i) with compound (ii) is in the range of 0.05 to 0.5, 0.05 to 0.45, 0.05 to 0.4, 0.8 to 0.35, 0.8 to 0.3, 0.1 to 0.25, 0.1 to 0.2, or 0.12 to 0.

18.

14. 13. The adhesive composition of claim 12, wherein the total degree of substitution of the polyisocyanate component (i) with compounds (ii) and (iii) is in the range of 0.15 to 0.65, in the range of 0.2 to 0.6, in the range of 0.25 to 0.6, or in the range of 0.3 to 0.

6.

15. 13. The adhesive composition of claim 12, wherein the at least one compound (ii) comprises an olefinic moiety as the free radical polymerization curable functional group.

16. The at least one compound (ii) is selected from hydroxy-substituted acrylate esters, hydroxy-substituted methacrylate esters, and mixtures thereof, and preferably the at least one compound (ii) is selected from hydroxy-(C ２ -C ２０ 16. The adhesive composition of claim 15, wherein compound (ii) is selected from alkyl-substituted methacrylate esters, polyalkoxylated monomethacrylate esters having 2 to 10 ether functional groups, and mixtures thereof, and preferably compound (ii) is selected from 2-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, and mixtures thereof.

17. 13. The adhesive composition according to claim 12, comprising from 0.05 to 1 meq / g, preferably from 0.06 to 0.5 meq / g, preferably from 0.08 to 0.4 meq / g, preferably from 0.1 to 0.3 meq / g, preferably from 0.12 to 0.25 meq / g, preferably from 0.15 to 0.2 meq / g of functional groups curable by free radical polymerization.

18. 13. The adhesive composition of claim 12, wherein the reduction in peel force of the adhesive after switching is from 30 to 99%, preferably from 50 to 99%, preferably from 70 to 99%.

19. 2. The adhesive composition of claim 1, wherein the crosslinking component (B) is obtained by reacting the polyisocyanate component (i) with the compound (iii), and the compound (ii) is not present.

20. 20. The adhesive composition of claim 19, wherein the degree of substitution of the polyisocyanate component (i) with the compound (iii) is in the range of 0.15 to 0.65, in the range of 0.2 to 0.6, in the range of 0.25 to 0.6, or in the range of 0.3 to 0.

6.

21. The at least one compound (iii) comprises one or more C １ -C ３０ Aliphatic alcohols, preferably linear, branched or cyclic C １ -C １８ Aliphatic alcohols, preferably linear, branched or cyclic C １ -C １２ Aliphatic alcohols, preferably branched C ３ -C １２ Aliphatic alcohol or branched C ６ -C １８ 13. The adhesive composition of claim 12, comprising or consisting of an aliphatic alcohol.

22. 2. The adhesive composition of claim 1, wherein the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to nucleophilic functional groups having an active hydrogen atom in the polymer component (A) is at least 0.81, at least 0.82, at least 0.83, at least 0.84, at least 0.85, at least 0.86, at least 0.87, at least 0.88, at least 0.89, at least 0.90, at least 0.91, at least 0.92, at least 0.93, at least 0.94, or at least 0.

95.

23. 2. The adhesive composition of claim 1, wherein the maximum degree of substitution of the polyisocyanate component (i) with water is 0.1 or less, preferably 0.08 or less, preferably 0.06 or less, preferably 0.05 or less, preferably 0.04 or less.

24. 10. The adhesive composition of claim 1 further comprising a photoinitiator, preferably 0.05 to 5 wt% of a photoinitiator, preferably 0.1 to 5 wt% of a photoinitiator, preferably 0.2 to 2 wt% of a photoinitiator.

25. 25. The adhesive composition of claim 24, wherein the at least one compound (iii) comprises or consists of one or more hydroxy-substituted photoinitiators.

26. 25. The adhesive composition of claim 24, wherein the photoinitiator is reactive to UV light.

27. The photopolymerization initiator may be benzoin and derivatives, benzophenone and derivatives, acetophenone, 4-phenoxyacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one. , 2-ethylanthraquinone, benzil dimethyl ketal, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methylpropanone, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methylpropionyl)benzyl)-phenyl)-2-methylpropan-1-one, 2-hydroxy-2-methylpropiophenone, and ethyl 4-(dimethylamino)benzoate.

28. The adhesive composition of claim 1 further comprising a solvent.

29. The adhesive composition of claim 1 further comprising a stabilizer.

30. (a) to form the cross-linking component (B), (i) a polyisocyanate component having an average of 1.8 to 6 isocyanate functional groups per molecule, (ii) at least one compound containing a functional group curable by free radical polymerization and further containing a nucleophilic functional group having an active hydrogen atom; and (iii) at least one compound containing a nucleophilic functional group having an active hydrogen atom and no functional group curable by free radical polymerization; wherein the total degree of substitution of the polyisocyanate component (i) with compounds (ii) and (iii) is in the range of 0.1 to 0.7; (b) a second step of combining the cross-linking component (B) formed in step (a) with a polymer component (A), said polymer component (A) having a weight average molecular weight in the range of 1,000 to 100,000 Daltons and having an average of X nucleophilic functional groups having active hydrogen atoms per molecule, where X represents a number having a value of at least 2; 1. A method for preparing an adhesive composition comprising: the amounts of the crosslinking component (B) and the polymer component (A) are selected so that the molar ratio of unsubstituted isocyanate functional groups in the crosslinking component (B) to nucleophilic functional groups having active hydrogen atoms in the polymer component (A) is at least 0.

8.

31. 31. The method of claim 30, wherein step (a) and / or step (b) is carried out in the presence of a catalyst.

32. 32. The method of claim 30 or claim 31, wherein step (a) and / or step (b) is carried out in the presence of a solvent.

33. 31. The method of claim 30, wherein the adhesive composition is an adhesive composition according to any one of claims 1 to 29.

34. 30. An adhesive medical device comprising a layer of the adhesive composition of any one of claims 1 to 29 disposed on a first carrier film, and a release liner disposed over the layer of adhesive.

35. The adhesive medical device of claim 34, wherein the first carrier film is UV translucent and optionally has a removable UV blocking layer laminated to the surface of the first carrier film opposite the adhesive composition.

36. 35. A method of treating a wound using the adhesive medical device of claim 34, comprising removing the release liner and applying the adhesive medical device to the wound.

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