Patent Description:
In various industries, components of devices are joined together using an adhesive, such as a pressure sensitive adhesive, a hot melt adhesive, or a structural adhesive. As devices are miniaturized, the need for higher precision delivery of adhesives increases. Moreover, there are certain shapes of adhesives that cannot be prepared by die-cutting of an adhesive, for instance a wedge shape.

<CIT> discloses a multilayer pressure sensitive adhesive assembly comprising at least a first pressure sensitive adhesive layer superimposed to a second polymer layer, wherein a curable liquid precursor of the first pressure sensitive adhesive polymer layer comprises a low Tg (meth)acrylate copolymer and a high Tg (meth)acrylate copolymer having a weight average molecular weight (Mw) of above <NUM>,<NUM> Daltons.

<CIT> discloses optical security articles comprising a first layer substantially transparent to visible light and having a first refractive index, the first layer having a relief pattern on a first surface thereof and a substantially smooth second surface, and an adhesive layer coterminating with the first layer. The adhesive layer substantially completely fills and makes contact with a first portion of the plurality of geometric concavities, the adhesive layer having a second refractive index which is substantially similar to the first refractive index of the first layer. A second portion of the plurality of geometric concavities are precluded from contact with the adhesive layer by a corresponding plurality of separation layers, each separation layer having a separation layer refractive index which is different from the refractive index of the first layer.

<CIT> discloses methods for making differentially pattern cured microstructured articles, using a molding tool having a microstructured surface, a patterned irradiation to generate irradiated and non-irradiated regions in a radiation curable resin.

The present disclosure relates to additive manufacturing of adhesives. It has been discovered that there exists a need for additional methods for manufacturing adhesives, such as continuous methods.

In a first aspect, a continuous method of making an adhesive is provided. The method includes obtaining an actinic radiation-polymerizable adhesive precursor composition disposed on a major surface of an actinic radiation-transparent substrate and irradiating a first portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a first irradiation dosage to form a first adhesive. The method further includes moving the actinic radiation-transparent substrate and irradiating a second portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a second irradiation dosage to form a second adhesive. The first adhesive and the second adhesive are individual adhesives separated from each other by approximately the distance the actinic radiation-transparent substrate was moved.

In a second aspect, another continuous method of making an adhesive is provided. The method includes obtaining an actinic radiation-polymerizable adhesive precursor composition disposed on a major surface of an actinic radiation-transparent substrate and irradiating a first portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a first irradiation dosage. The method further includes irradiating a second portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a second irradiation dosage and moving the actinic radiation-transparent substrate. The first portion and the second portion are adjacent to or overlapping with each other and the first irradiation dosage and the second irradiation dosage are not the same, thereby forming an integral adhesive having a variable thickness in an axis normal to the actinic radiation-transparent substrate.

The above summary of the present disclosure is not intended to describe each disclosed aspect or every implementation of the present disclosure.

The present disclosure provides methods for the additive manufacturing of adhesives, such as continuous manufacturing of the adhesives. In certain embodiments, integral adhesives having variations in thickness are formed, while in other embodiments a plurality of adhesives having approximately the same thickness are formed.

For the following Glossary of defined terms, these definitions shall be applied for the entire application, unless a different definition is provided in the claims or elsewhere in the specification.

Certain terms are used throughout the description and the claims that, while for the most part are well known, may require some explanation. It should be understood that, as used herein:
As used in this specification and the appended embodiments, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended embodiments, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

As used in this specification, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. <NUM> to <NUM> includes <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>).

Unless otherwise indicated, all numbers expressing quantities or ingredients, measurement of properties and so forth used in the specification and embodiments are to be understood as being modified in all instances by the term "about.

The term "actinic radiation" refers to electromagnetic radiation that can produce photochemical reactions.

The term "dosage" means a level of exposure to of actinic radiation.

The term "integral" means composed of parts that together constitute a whole.

The term "(co)polymer" is inclusive of both homopolymers containing a single monomer and copolymers containing two or more different monomers.

The term "(meth)acrylic" or "(meth)acrylate" is inclusive of both acrylic and methacrylic (or acrylate and methacrylate). Acrylate and methacrylate monomers, oligomers, or polymers are referred to collectively herein as "acrylates".

The term "aliphatic group" means a saturated or unsaturated linear or branched hydrocarbon group. This term is used to encompass alkyl, alkenyl, and alkynyl groups, for example.

The term "alkyl group" means a saturated hydrocarbon group that is linear, branched, cyclic, or combinations thereof and typically has <NUM> to <NUM> carbon atoms. In some embodiments, the alkyl group contains <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM> carbon atoms. Examples of alkyl group include without limitation, methyl, ethyl, isopropyl, t-butyl, heptyl, dodecyl, octadecyl, amyl, <NUM>-ethylhexyl, and the like. The term "alkylene group" refers to a divalent alkyl group.

The term "alicyclic group" means a cyclic hydrocarbon group having properties resembling those of aliphatic groups. The term "aromatic group" or "aryl group" means a mono- or polynuclear aromatic hydrocarbon group.

The term "pattern" with respect to an adhesive refers to a design of an adhesive that defines at least one aperture in the adhesive.

The term "solvent" refers to a substance that dissolves another substance to form a solution.

The term "total monomer" refers to the combination of all monomers in an adhesive composition, including both in a polymerized reaction product and in optional additional materials.

Reference throughout this specification to "one embodiment," "certain embodiments," "one or more embodiments" or "an embodiment," whether or not including the term "exemplary" preceding the term "embodiment," means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the certain exemplary embodiments of the present disclosure. Thus, the appearances of the phrases such as "in one or more embodiments," "in some embodiments," "in certain embodiments," "in one embodiment," "in many embodiments" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the certain exemplary embodiments of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

Various exemplary embodiments of the disclosure will now be described. Exemplary embodiments of the present disclosure may take on various modifications and alterations without departing from the scope of the disclosure. Accordingly, it is to be understood that the embodiments of the present disclosure are not to be limited to the following described exemplary embodiments, but are to be controlled by the limitations set forth in the claims.

In a first aspect, a continuous method is provided. The method includes obtaining an actinic radiation-polymerizable adhesive precursor composition disposed on a major surface of an actinic radiation-transparent substrate and irradiating a first portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a first irradiation dosage to form a first adhesive. The method further includes moving the actinic radiation-transparent substrate and irradiating a second portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a second irradiation dosage to form a second adhesive.

The below disclosure relates to both the first and second aspects.

Such continuous methods are adaptable for manufacturing a variety of adhesive structures. For instance, a continuous method can form a series or array of individual adhesives each separated from each other by approximately the distance the substrate was moved in between irradiation of the separate adhesives. The individual adhesives in some embodiments have the same dimensions of height, length, and width as each other. In contrast, the individual adhesives in other embodiments differ from each other in at least one of height (i.e., z-direction from a major surface of the substrate), length, and width. Advantageously, the methods of the present disclosure provide the capability to easily manufacture individual adhesives having a number of unique shapes due to employing adaptable actinic radiation sources, from which the bounds and dosage of the actinic radiation determine the specific shape of an individual adhesive. For instance, digital light projectors, laser scanning devices, and liquid crystal displays can all be controlled to change the area and intensity of the actinic radiation that causes curing of the actinic radiation-polymerizable adhesive precursor composition.

As noted above, die-cutting of an adhesive is not readily capable of forming adhesives having a wedge shape. Similarly, die-cutting is not amenable to forming an adhesive that has a height gradient or other unique shapes. The (continuous) methods of the present disclosure not only provide a wide variety of shapes and gradients, but also can manufacture multiple different shapes and heights on the same substrate.

Hence, in certain embodiments, methods of the first aspect further comprise irradiating a third portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate prior to moving the substrate, wherein the first portion and the third portion are adjacent to or overlapping with each other. When the first irradiation dosage and the third irradiation dosage are not the same, an integral adhesive is formed comprising a variable thickness in an axis normal to the actinic radiation-transparent substrate. In certain embodiments, the time of irradiation of the first dosage is shorter or longer than the time of irradiation of the third dosage. In certain embodiments, the actinic radiation intensity of the first dosage is lower or higher than the actinic radiation intensity of the third dosage. In certain embodiments, irradiating the first portion occurs before irradiating the third portion, at the same time as irradiating the third portion, or a combination thereof.

Optionally, methods of the first aspect further comprise irradiating a fourth portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate. When the second portion and the fourth portion are adjacent to or overlapping with each other and the second irradiation dosage and the fourth irradiation dosage are not the same, a second integral adhesive comprising a variable thickness in an axis normal to the major surface of the actinic radiation-transparent substrate. In certain embodiments, the time of irradiation of the second dosage is shorter or longer than the time of irradiation of the fourth dosage. In certain embodiments, the actinic radiation intensity of the second dosage is lower or higher than the actinic radiation intensity of the fourth dosage. In certain embodiments, irradiating the second portion occurs before irradiating the fourth portion, at the same time as irradiating the fourth portion, or a combination thereof.

Alternatively, in certain embodiments the method comprises applying the same irradiation dosage to a number of different portions of the actinic radiation-polymerizable adhesive precursor composition (e.g., to both the first portion and the third portion), thereby forming a pattern of adhesive having the same thickness in an axis normal to the major surface of the actinic radiation-transparent substrate. The pattern includes one or more individual adhesives that can be either integral or separate from one or more other individual adhesives of the same height.

In certain embodiments, methods of the second aspect further comprise irradiating a third portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a third irradiation dosage, after moving the substrate. Optionally, the first irradiation dosage and the third irradiation dosage are the same or different. Moreover, methods of the second aspect may further comprise irradiating a fourth portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a fourth irradiation dosage. The third portion and the fourth portion are adjacent to or overlapping with each other and the third irradiation dosage and the fourth irradiation dosage are not the same, thereby forming an integral adhesive. In such embodiments, the actinic radiation-transparent substrate is moved after irradiating the fourth portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate.

In most embodiments, the (e.g., integral) adhesive is a pressure sensitive adhesive (PSA), a structural adhesive, a structural hybrid adhesive, a hot melt adhesive, or a combination thereof. For example, the adhesive is often prepared from an actinic radiation-polymerizable adhesive precursor composition comprising an acrylate, a two-part acrylate and epoxy system, a two-part acrylate and urethane system, or a combination thereof. In certain embodiments, the actinic radiation-polymerizable adhesive precursor composition is a <NUM>% polymerizable precursor composition, while in other embodiments the actinic radiation-polymerizable adhesive precursor composition comprises at least one solvent, such as for instance and without limitation C4-C12 alkanes (e.g., heptanes), alcohols (e.g., methanol, ethanol, or isopropanol), ethers, and esters.

The acrylic polymer can be, for example, an acrylic acid ester of a non-tertiary alcohol having from <NUM> to <NUM> carbon atoms. In some embodiments, the acrylic acid ester includes a carbon-to-carbon chain having <NUM> to <NUM> carbon atoms and terminates at the hydroxyl oxygen atom, the chain containing at least half of the total number of carbon atoms in the molecule.

Certain useful acrylic acid esters are polymerizable to a tacky, stretchable, and elastic adhesive. Examples of acrylic acid esters of nontertiary alcohols include but are not limited to <NUM>-methylbutyl acrylate, isooctyl acrylate, lauryl acrylate, <NUM>-methyl-<NUM>-pentyl acrylate, isoamyl acrylate, sec-butyl acrylate, n-butyl acrylate, n-hexyl acrylate, <NUM>- ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, isodecyl acrylate, isodecyl methacrylate, and isononyl acrylate. Suitable acrylic acid esters of non tertiary alcohols include, for example, <NUM>-ethylhexyl acrylate and isooctylacrylate.

To enhance the strength of the adhesive, the acrylic acid ester may be copolymerized with one or more monoethylenically unsaturated monomers that have highly polar groups. Such monoethylenically unsaturated monomer such as acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, N- substituted acrylamides (for example, N,N-dimethyl acrylamide), acrylonitrile, methacrylonitrile, hydroxyalkyl acrylates, cyanoethyl acrylate, N-vinylpyrrolidone, N-vinylcaprolactam, and maleic anhydride. In some embodiments, these copolymerizable monomers are used in amounts of less than <NUM>% by weight of the adhesive matrix such that the adhesive is tacky at ordinary room temperatures. In some cases, tackiness can be preserved at up to <NUM>% by weight of N-vinylpyrrolidone.

Especially useful are acrylate copolymers comprising at least <NUM>% by weight acrylic acid, and in other embodiments, at least <NUM>% by weight, or at least <NUM>% by weight acrylic acid, each based on the total weight of the monomers in the acrylate copolymer. The adhesive may also include small amounts of other useful copolymerizable monoethylenically unsaturated monomers such as alkyl vinyl ethers, vinylidene chloride, styrene, and vinyltoluene.

In certain embodiments, adhesives according to the present disclosure comprise two-part acrylate and epoxy systems. For instance, suitable acrylate-epoxy compositions are described in detail in<CIT><CIT>) In certain embodiments, adhesives according to the present disclosure comprise two-part acrylate and urethane systems. For instance, suitable acrylate-urethane compositions are described in detail in <CIT>).

Enhancement of the cohesive strength of the adhesive may also be achieved through the use of a crosslinking agent such as <NUM>,<NUM>-hexanediol diacrylate, with a photoactive triazine crosslinking agent such as taught in <CIT>) and <CIT>), or with a heat-activatable crosslinking agent such as a lower-alkoxylated amino formaldehyde condensate having C1-<NUM> alkyl groups-for example, hexamethoxymethyl melamine or tetramethoxymethyl urea or tetrabutoxymethyl urea. Crosslinking may be achieved by irradiating the composition with electron beam (or "e-beam") radiation, gamma radiation, or x-ray radiation. Bisamide crosslinkers may be used with acrylic adhesives in solution.

In a typical photopolymerization method, a monomer mixture may be irradiated with actinic radiation, such as for example ultraviolet (UV) rays, in the presence of a photopolymerization initiator (i.e., photoinitiators). Suitable exemplary photoinitiators are those available under the trade designations IRGACURE and DAROCUR from BASF (Ludwigshafen, Germany) and include <NUM>-hydroxycyclohexyl phenyl ketone (IRGACURE <NUM>), <NUM>,<NUM>-dimethoxy-<NUM>,<NUM>-diphenylethan-<NUM>-one (IRGACURE <NUM>), bis(<NUM>,<NUM>,<NUM>-trimethylbenzoyl)phenylphosphineoxide (IRGACURE <NUM>), <NUM>-[<NUM>-(<NUM>-hydroxyethoxy)phenyl]-<NUM>-hydroxy-<NUM>-methyl-<NUM>-propane-<NUM>-one (IRGACURE <NUM>), <NUM>-benzyl-<NUM>-dimethylamino-<NUM>-(<NUM>-morpholinophenyl)butanone (IRGACURE <NUM>), <NUM>-methyl-<NUM>-[<NUM>-(methylthio)phenyl]-<NUM>-morpholinopropan-<NUM>-one (IRGACURE <NUM>), Oligo[<NUM>-hydroxy-<NUM>-methyl-<NUM>-[<NUM>- (<NUM>-methylvinyl)phenyl]propanone] ESACURE ONE (Lamberti S. , Gallarate, Italy), <NUM>-hydroxy-<NUM>-methyl-<NUM>-phenyl propan-<NUM>-one (DAROCUR <NUM>), <NUM>, <NUM>, <NUM>-trimethylbenzoyldiphenylphosphine oxide (IRGACURE TPO), and <NUM>, <NUM>, <NUM>-trimethylbenzoylphenyl phosphinate (IRGACURE TPO-L). Additional suitable photoinitiators include for example and without limitation, benzyl dimethyl ketal, <NUM>-methyl-<NUM>-hydroxypropiophenone, benzoin methyl ether, benzoin isopropyl ether, anisoin methyl ether, aromatic sulfonyl chlorides, photoactive oximes, and combinations thereof. When used, a photoinitiator is typically present in an amount between about <NUM> to about <NUM> parts, or from <NUM> to <NUM> parts, per <NUM> parts by weight of total monomer.

In many embodiments, the method comprises post-curing the one or more formed adhesives (e.g., the first adhesive, the second adhesive, the integral adhesive, etc.), for instance post-curing using actinic radiation or heat. In such embodiments, by not requiring an adhesive to be cured to the full extent needed for a particular application during an initial irradiation, radiation variables can be focused on polymerizing to form a desired shape and size.

The post-cure of the adhesive is optionally initiated using a thermal initiator. Suitable thermal initiators include for example and without limitation, <NUM>,<NUM>'-azobis(<NUM>,<NUM>-dimethylvaleronitrile), <NUM>,<NUM>'-azobisoisobutyronitrile (VAZO <NUM>, available from E. du Pont de Nemours Co. ), <NUM>,<NUM>'-azobis(<NUM>,<NUM>-dimethylpentanenitrile) (VAZO <NUM>, available from E. du Pont de Nemours Co. ), <NUM>,<NUM>'-azobis-<NUM>-methylbutyronitrile, (<NUM>,<NUM>'-azobis(<NUM>-cyclohexanecarbonitrile), <NUM>,<NUM>'-azobis(methyl isobutyrate), <NUM>,<NUM>'-azobis(<NUM>-amidinopropane) dihydrochloride, <NUM>,<NUM>'-azobis(<NUM>-methoxy-<NUM>,<NUM>-dimethylvaleronitrile), <NUM>,<NUM>'-azobis(<NUM>-cyanopentanoic acid) and its soluble salts (e.g., sodium, potassium)benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di(<NUM>-t-butylcyclohexyl) peroxydicarbonate, di(<NUM>-ethylhexyl) peroxydicarbonate, t-butylperoxypivalate, t-butylperoxy-<NUM>-ethylhexanoate, dicumyl peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, combinations of the persulfates with sodium metabisulfite or sodium bisulfite, benzoyl peroxide plus dimethylaniline, cumene hydroperoxide plus cobalt naphthenate, and combinations thereof. When used, a thermal initiator is typically present in an amount from about <NUM> to about <NUM> parts, or from <NUM> to <NUM> parts, per <NUM> parts by weight of total monomer.

The method often further comprises removing actinic radiation-polymerizable adhesive precursor composition remaining in contact with the adhesives (e.g., the first adhesive, the second adhesive, the integral adhesive, etc.). Removing precursor composition that has not been polymerized after the irradiating may involve the use of gravity, a gas, a vacuum, a fluid, or any combination thereof. Optionally, a suitable fluid for removing excess adhesive precursor composition includes a solvent. When the adhesive will be post-cured, it may be particularly desirable to remove residual precursor composition from being in contact with the adhesive, to minimize or prevent the addition of adhesive material to the desired shape and size of the adhesive upon post-curing.

The temperature(s) at which methods according to the present disclosure are performed is not particularly limited. For methods employing an actinic radiation-polymerizable adhesive precursor composition that is in a liquid form at room temperature (e.g., <NUM>-<NUM> degrees Celsius), for simplicity at least some of the various steps of the method are typically performed at room temperature. For methods employing an actinic radiation-polymerizable adhesive precursor composition that is in a solid form at room temperature, at least some of the various steps of the method may be performed at an elevated temperature above room temperature such that the actinic radiation-polymerizable adhesive precursor composition is in a liquid form. Elevated temperatures may be used through an entire method, or through such steps as formation of an adhesive, removal of unpolymerized actinic radiation-polymerizable adhesive precursor composition, and/or optional post-curing of the adhesive. In some embodiments, certain portions of the method are performed at different temperatures, whereas in some other embodiments, the entire method is performed at one temperature. Suitable elevated temperatures include for instance and without limitation, above <NUM> degrees Celsius and up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, up to <NUM> degrees Celsius, or up to <NUM> degrees Celsius. In certain embodiments, the method is performed at a temperature between <NUM> degrees Celsius and <NUM> degrees Celsius, inclusive; between <NUM> degrees Celsius and <NUM> degrees Celsius, inclusive; between <NUM> degrees Celsius and <NUM> degrees Celsius, inclusive; or between <NUM> degrees Celsius and <NUM> degrees Celsius, inclusive. The temperature employed is typically limited only by the lowest maximum temperature at which a material used in the method (e.g., a substrate, an apparatus component, etc.) remains thermally stable.

In certain embodiments, the method is performed on an apparatus that is separate from other materials used in an end application for the one or more formed adhesives. In such embodiments, the method further comprises removing the first integral adhesive from the substrate, as discussed in further detail below.

The resulting adhesive is an adhesive due to its ability to adhere two materials together. Characteristics such as specific peel force, tackiness, etc., are not particularly limited as long as the formed adhesive adheres two material together (e.g., two layers in a multilayer construction, two components of a device, and the like). Typically, such a test involves disposing the formed adhesive between two substrates (one or both may be polymeric, glass, ceramic, or metal), lifting the article by the edges of one of the substrates, and observing whether or not the second substrate remains attached to the article.

In certain embodiments, the adhesive comprises variations in index of refraction. Such variations are typically formed as artifacts of the irradiation of the actinic radiation-polymerizable adhesive precursor composition with the various irradiation sources. For instance, for an integral adhesive having variability in its thickness, often there will be a variation in the index of refraction between the portions of the integral adhesive that were subjected to different dosages to form the variability in the thickness.

Referring to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes an actinic radiation-transparent substrate <NUM> having a major surface <NUM> and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto the major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. In the apparatus illustrated in <FIG>, the means for depositing <NUM> a composition <NUM> onto the major surface <NUM> of the actinic radiation-transparent substrate <NUM> comprises an open container holding a volume of the composition <NUM> positioned adjacent to the substrate <NUM> such that a portion of the major surface <NUM> of the substrate <NUM> is in contact with the composition <NUM>. The contact deposits the composition <NUM> on the major surface <NUM> of the substrate <NUM>, then as the means for conveying <NUM> the substrate <NUM> rotates, the composition <NUM> continues to be deposited on the portions of the major surface <NUM> of the substrate <NUM> that come into contact with the composition <NUM> held in the container <NUM>.

In certain embodiments, the apparatus <NUM> further comprises an air knife <NUM> configured to remove a composition from the substrate. Air knives are well known in the art and use compressed air to blow off contaminants, excess materials, etc. from a product or apparatus.

The apparatus optionally further comprises a second substrate <NUM>. The substrate is not particularly limited in material or surface structure; for example the second substrate <NUM> illustrated in <FIG> comprises a structured sheet, in which at least one major surface <NUM> of the sheet is structured (as opposed to flat and featureless). Suitable sheet materials include for instance and without limitation, polymeric materials selected from polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, cycloolefin films, poly(methyl methacrylate), or a combination thereof. The second substrate may be a film, such as a single layer film or multilayer film having either a smooth surface or structured surface. Suitable structured surfaces include microstructured surfaces or embossed surfaces. Typically, a second substrate is employed to remove an adhesive from the actinic radiation-transparent substrate following irradiation from the actinic radiation. The second substrate <NUM> can be secured adjacent to and separate from the actinic radiation-transparent substrate <NUM> using a roller <NUM> or other suitable means.

In certain embodiments, the apparatus <NUM> further comprises a scraper <NUM> configured to scrape the substrate and/or a tacky roller <NUM> configured to clean the substrate. Other cleaning mechanisms for removing adhesive and/or un-polymerized composition from the substrate could alternatively be employed to prepare the substrate for the deposition of additional composition on its major surface, e.g., washing with a solvent. Moreover, in certain embodiments the substrate comprises a release material coated on the major surface of the substrate to enhance the ease of removal of the adhesive formed on the substrate. Suitable release materials include for instance and without limitation, silicone materials and low adhesion coatings. One example of a suitable low adhesion coating can be coated as a solution of polyvinyl N-octadecyl carbamate and a blend of silicone resins, as described in <CIT>).

In many embodiments, the actinic radiation-transparent substrate <NUM> is in the form of a cylinder. The means for depositing <NUM> a composition <NUM> on a cylindrical substrate <NUM> may comprise rotating the cylinder (e.g., actinic radiation-transparent substrate) through a volume of the composition <NUM> to apply the composition <NUM> on the major surface <NUM> of the substrate <NUM>. Advantageously, it is not always necessary to have strict control over the thickness of a composition that is deposited on the substrate because the irradiation dosage from the irradiation source is selected to polymerize a predetermined shape and size of the composition, as opposed to polymerizing through an entire thickness of the composition regardless of its particular depth.

In certain embodiments of methods according to the present disclosure, in use the apparatus shown in <FIG> is operated as follows: A means for conveying <NUM> the actinic radiation-transparent substrate <NUM> rotates the actinic radiation-transparent substrate <NUM> through the means for depositing <NUM> a composition <NUM>, thereby depositing the composition <NUM> on the major surface <NUM> of the substrate <NUM> with which it contacts. An irradiation source <NUM> directs radiation through the actinic radiation-transparent substrate <NUM> at one or more predetermined dosages at one or more predetermined locations. The composition <NUM> that has been irradiated at least partially polymerizes, forming at least one adhesive, such as the adhesive <NUM> and the adhesive <NUM>, shown in <FIG>. For example, the adhesive <NUM> comprises a variation in thickness as a result of the specific irradiation provided by the irradiation source <NUM>. As the substrate <NUM> continues to rotate (in the direction of the arrow, for instance), an air knife <NUM> directs air towards the major surface <NUM> of the substrate <NUM> to assist in removing the composition <NUM> remaining on the major surface <NUM> of the substrate <NUM> that was not polymerized to form an adhesive. The excess composition <NUM> is preferably returned to the container <NUM> via gravity once it is no longer deposited on the substrate <NUM>. Once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches the second substrate <NUM> via rotation of the actinic radiation-transparent substrate <NUM>, the adhesive (<NUM>, <NUM>) is transferred from the major surface <NUM> of the substrate <NUM> to a major surface <NUM> of the second substrate <NUM>. As the substrate <NUM> continues to rotate, a scraper <NUM> contacts the major surface <NUM> of the substrate <NUM> and removes residual adhesive from the substrate <NUM>. Further, a tacky roller <NUM> contacts the major surface <NUM> of the substrate and removes residual adhesive from the substrate <NUM>. It will be understood that not every apparatus <NUM> will include both or either of a scraper <NUM> and a tacky roller <NUM>, as these can be optional components.

For instance, referring to the first aspect, a method may include obtaining an actinic radiation-polymerizable adhesive precursor composition <NUM> disposed on a major surface <NUM> of an actinic radiation-transparent substrate <NUM> and irradiating a first portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate <NUM> for a first irradiation dosage to form a first adhesive <NUM>. The method further includes moving the actinic radiation-transparent substrate <NUM> and irradiating a second portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate <NUM> for a second irradiation dosage to form a second adhesive <NUM>. In embodiments in which the method further includes irradiating a third portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate <NUM> for a third irradiation dosage prior to moving the substrate, and the first portion and the third portion are adjacent to or overlapping with each other, an integral adhesive <NUM> is formed comprising a variable thickness in an axis normal to the actinic radiation-transparent substrate <NUM> when the first irradiation dosage and the third irradiation dosage are not the same.

Referring to the second aspect, a method may include obtaining an actinic radiation-polymerizable adhesive precursor composition <NUM> disposed on a major surface <NUM> of an actinic radiation-transparent substrate <NUM> and irradiating a first portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate <NUM> for a first irradiation dosage. The method further includes irradiating a second portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a second irradiation dosage and moving the actinic radiation-transparent substrate. The first portion and the second portion are adjacent to or overlapping with each other and the first irradiation dosage and the second irradiation dosage are not the same, thereby forming an integral adhesive <NUM> having a variable thickness in an axis normal to the actinic radiation-transparent substrate <NUM>.

Referring now to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes an actinic radiation-transparent substrate <NUM> having a major surface <NUM> and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto the major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. The schematic of the apparatus <NUM> shown in <FIG> further comprises an air knife <NUM> configured to remove nonpolymerized composition <NUM> from the substrate <NUM>. Also, the apparatus <NUM> of certain embodiments includes a second irradiation source <NUM> configured to irradiate one or more adhesives (e.g., the adhesive <NUM> and the adhesive <NUM>) through a second substrate <NUM> as they pass by the second irradiation source <NUM>. Typically, the use of a second irradiation source <NUM> is effective to post-cure the one or more adhesives. The second substrate <NUM> is often a consumable material obtained separately from the apparatus, and in the illustrated embodiment, comprises a structured sheet, in which at least one major surface <NUM> of the sheet is structured (as opposed to flat and featureless). The second substrate <NUM> can be secured adjacent to and separate from the actinic radiation-transparent substrate <NUM> using a roller <NUM> or other suitable means. The apparatus <NUM> shown in <FIG> further includes an actinic radiation-transparent film <NUM> having a major surface <NUM>. The actinic radiation-transparent film <NUM> is wrapped at least partially around the actinic radiation-transparent substrate <NUM>, and acts to protect the major surface <NUM> of the substrate <NUM> from residual composition <NUM> and adhesive material resistant to cleaning.

In use, the apparatus <NUM> operates similarly to the apparatus <NUM> of <FIG> described above, including that the composition <NUM> that has been irradiated at least partially polymerizes, forming at least one adhesive, such as the adhesive <NUM> and the adhesive <NUM>. Once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches a second substrate <NUM> via rotation of the actinic radiation-transparent substrate <NUM>, the adhesive (<NUM>, <NUM>) is transferred from the major surface <NUM> of the substrate <NUM> to a major surface <NUM> of the second substrate <NUM>. Further, in certain embodiments, the formed adhesive (<NUM>, <NUM>) is irradiated by the second irradiation source <NUM> to post-cure the adhesive prior to transfer from the (first) substrate <NUM> to the second substrate <NUM>.

Referring to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes an actinic radiation-transparent substrate <NUM> having a major surface <NUM> and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto the major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. The schematic of the apparatus <NUM> shown in <FIG> further comprises an air knife <NUM> configured to remove nonpolymerized composition <NUM> from the substrate <NUM>, as well as a plurality of second irradiation sources <NUM> configured to irradiate one or more adhesives (e.g., the adhesive <NUM> and the adhesive <NUM>) through a second substrate <NUM> as they pass by the second irradiation source <NUM>. Typically, the use of at least one second irradiation source <NUM> is effective to post-cure the one or more adhesives. The second substrate <NUM> is often a consumable material obtained separately from the apparatus, and in the illustrated embodiment, comprises a smooth sheet. The second substrate <NUM> can be secured adjacent to and separate from the actinic radiation-transparent substrate <NUM> using a roller <NUM> or other suitable means. In certain embodiments, the apparatus <NUM> further comprises a scraper <NUM> configured to scrape the substrate <NUM> and/or a tacky roller <NUM> configured to clean the substrate <NUM>.

In use, the apparatus <NUM> operates similarly to the apparatus <NUM> of <FIG> described above, including that the composition <NUM> that has been irradiated at least partially polymerizes, forming at least one adhesive, such as the adhesive <NUM> and the adhesive <NUM>. Once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches a second substrate <NUM> via rotation of the actinic radiation-transparent substrate <NUM>, the adhesive (<NUM>, <NUM>) is transferred from the major surface <NUM> of the substrate <NUM> to a major surface <NUM> of the second substrate <NUM>. Further, in certain embodiments, the formed adhesive (<NUM>, <NUM>) is irradiated by one or more second irradiation sources <NUM> to post-cure the adhesive prior to transfer from the (first) substrate <NUM> to the second substrate <NUM>.

Referring to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes an actinic radiation-transparent substrate <NUM> having a major surface <NUM> and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto the major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. Optionally, an air knife <NUM> configured to remove nonpolymerized composition <NUM> from the substrate <NUM> is provided with the apparatus. The schematic of the apparatus <NUM> shown in <FIG> further comprises a mechanism <NUM> configured to remove one or more adhesives (e.g., the adhesive <NUM>) through a second substrate <NUM> as they pass by the mechanism. For instance, the mechanism can be a robotic mechanism having a movable arm <NUM> and a replaceable end effector <NUM> configured to detach one or more adhesives <NUM> from the actinic radiation-transparent substrate <NUM>. In the embodiment shown in <FIG>, the end effector <NUM> comprises a major surface <NUM> configured to be shaped to be an inverse of the shape of an upper major surface of the adhesive <NUM>. The mechanism <NUM> is typically configured to place the adhesive <NUM> in a location separate from the apparatus <NUM>, such as on another substrate, on a device, on a release liner, in a storage container, etc. In certain embodiments, the apparatus <NUM> further comprises a scraper <NUM> configured to scrape the substrate <NUM> and/or a tacky roller <NUM> configured to clean the substrate <NUM>.

In use, the apparatus <NUM> operates similarly to the apparatus <NUM> of <FIG> described above, including that the composition <NUM> that has been irradiated at least partially polymerizes, forming at least one adhesive, such as the adhesive <NUM> and the adhesive <NUM>. However, once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches the mechanism <NUM> via rotation of the actinic radiation-transparent substrate <NUM>, the adhesive (<NUM>, <NUM>) is transferred from the major surface <NUM> of the substrate <NUM> to a major surface <NUM> of the end effector <NUM> of the mechanism <NUM>.

Referring to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes at least two rollers <NUM> and <NUM> (at least one of which is configured to convey an actinic radiation-transparent substrate <NUM>), and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto a major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. The means for depositing <NUM> comprises a container configured to dispense the composition <NUM> as a pool on the major surface <NUM> of the substrate <NUM>. The actinic radiation-transparent substrate <NUM> is often a consumable material obtained separately from the apparatus as opposed to being a component of the apparatus. Optionally, an air knife <NUM> configured to remove nonpolymerized composition <NUM> from the substrate <NUM> where one or more adhesives <NUM> and <NUM> are formed is provided with the apparatus <NUM>.

In certain embodiments, in use the apparatus shown in <FIG> is operated as follows: A means for conveying <NUM> the actinic radiation-transparent substrate <NUM> drives a web of the actinic radiation-transparent substrate <NUM> through a plurality of rollers <NUM> that form a containment area to hold the composition <NUM> supplied by the means for depositing <NUM> the composition <NUM> on the major surface <NUM> of the substrate <NUM> with which it contacts. The means for depositing <NUM> in this embodiment is a container disposed above the actinic radiation-transparent substrate <NUM>. An irradiation source <NUM> directs radiation through the actinic radiation-transparent substrate <NUM> at one or more predetermined dosages at one or more predetermined locations. The composition <NUM> that has been irradiated at least partially polymerizes, forming at least one adhesive, such as the adhesive <NUM> and the adhesive <NUM>, shown in <FIG>. For example, the adhesive <NUM> comprises a variation in width as compared to the adhesive <NUM>, as a result of the specific irradiation provided by the irradiation source <NUM>. As the substrate <NUM> continues to be driven from an unwind roller <NUM> to the means for conveying <NUM> (e.g., a wind roller as shown in <FIG>), an air knife <NUM> directs air towards the major surface <NUM> of the substrate <NUM> to assist in removing the composition <NUM> remaining on the major surface <NUM> of the substrate <NUM> that was not polymerized to form an adhesive. The excess composition <NUM> is preferably returned to the containment area defined by the plurality of rollers <NUM>. Once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches the wind roller <NUM>, the web of actinic radiation transparent substrate <NUM> is wound up.

Referring to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes at least two rollers <NUM> and <NUM> (at least one of which is configured to convey an actinic radiation-transparent substrate <NUM>), and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto a major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. The actinic radiation-transparent substrate <NUM> is often a consumable material obtained separately from the apparatus as opposed to being a component of the apparatus. The means for depositing <NUM> comprises a container configured to dispense the composition <NUM> through a funnel <NUM> and as a pool on the major surface <NUM> of the substrate <NUM>. The apparatus further includes a dam roller <NUM> comprising a pair of spaced apart edges (not shown) configured to contact the actinic radiation-transparent substrate <NUM> and define a containment area between the edges to provide space for the pool of composition <NUM> disposed on the actinic radiation-transparent substrate <NUM>.

A further means may be provided to contact the dam roller <NUM> with the actinic radiation-transparent substrate <NUM> to assist in minimizing leakage of the composition <NUM> off the actinic radiation-transparent substrate <NUM>. In the apparatus shown in <FIG>, such a means includes three press rollers <NUM>, <NUM>, and <NUM> and a belt <NUM>, in which two of the press rollers <NUM>, <NUM> are disposed adjacent to the dam roller <NUM> and the third press roller <NUM> is disposed at a distance from the first two press rollers <NUM>, <NUM>. The belt <NUM> is configured in a loop around the three press rollers <NUM>, <NUM>, and <NUM> and disposed in contact with the actinic radiation-transparent substrate <NUM>. The three press rollers <NUM>, <NUM>, and <NUM> are configured to apply force to the belt to maintain it in contact with the actinic radiation-transparent substrate <NUM>. As the actinic radiation-transparent substrate <NUM> is conveyed, the belt <NUM> traverses around the three press rollers <NUM>, <NUM>, and <NUM>.

In use, the apparatus <NUM> operates similarly to the apparatus <NUM> of <FIG> described above, including that as the substrate <NUM> continues to be driven from an unwind roller <NUM> (as well as under the dam roller <NUM>) to the means for conveying <NUM> (e.g., a wind roller as shown in <FIG>), an air knife <NUM> directs air towards the major surface <NUM> of the substrate <NUM> to assist in removing the composition <NUM> remaining on the major surface <NUM> of the substrate <NUM> that was not polymerized to form an adhesive by irradiation from the actinic irradiation source <NUM>. The excess composition <NUM> is preferably returned to the containment area defined by the dam roller <NUM>. Once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches the wind roller <NUM>, the web of actinic radiation transparent substrate <NUM> is wound up.

Referring to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes at least two rollers <NUM> and <NUM> (at least one of which is configured to convey an actinic radiation-transparent substrate <NUM>) configured to convey an actinic radiation-transparent substrate <NUM> and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto a major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. The actinic radiation-transparent substrate <NUM> is often a consumable material obtained separately from the apparatus <NUM> as opposed to being a component of the apparatus. The apparatus further includes a dam roller <NUM> comprising a pair of spaced apart edges (not shown) configured to contact the actinic radiation-transparent substrate <NUM> and define a containment area between the edges to provide space for the pool of composition <NUM> disposed on the actinic radiation-transparent substrate <NUM>. The means for depositing <NUM> comprises a container configured to dispense the composition <NUM> as a thin layer onto a surface of the dam roller <NUM>, which travels around the dam roller <NUM> and forms a pool on the major surface <NUM> of the substrate <NUM>.

A further means may be provided to contact the dam roller <NUM> with the actinic radiation-transparent substrate <NUM> to assist in minimizing leakage of the composition <NUM> off the actinic radiation-transparent substrate <NUM>. In the apparatus shown in <FIG>, such a means includes two tension rollers <NUM> and <NUM>, wherein the actinic radiation-transparent substrate <NUM> is fed over one tension roller <NUM>, under the dam roller <NUM>, and over the other tension roller <NUM>. This configuration allows the tension rollers <NUM> and <NUM> to be configured to apply force to the actinic radiation-transparent substrate <NUM> to maintain the substrate <NUM> in contact with the dam roller <NUM> as the actinic radiation-transparent substrate <NUM> is conveyed through the apparatus.

In use, the apparatus <NUM> operates similarly to the apparatus <NUM> of <FIG> described above, including that as the substrate <NUM> continues to be driven from an unwind roller <NUM> (as well as over the first tension roller <NUM>, under the dam roller <NUM>, and over the second tension roller <NUM>) to the means for conveying <NUM> (e.g., a wind roller as shown in <FIG>), an air knife <NUM> directs air towards the major surface <NUM> of the substrate <NUM> to assist in removing the composition <NUM> remaining on the major surface <NUM> of the substrate <NUM> that was not polymerized to form an adhesive by irradiation from the actinic irradiation source <NUM>. The excess composition <NUM> is preferably returned to the containment area defined by the dam roller <NUM>. Once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches the wind roller <NUM>, the web of actinic radiation transparent substrate <NUM> is wound up.

A further means may be provided to contact the dam roller <NUM> with the actinic radiation-transparent substrate <NUM> to assist in minimizing leakage of the composition <NUM> off the actinic radiation-transparent substrate <NUM>. In the apparatus shown in <FIG>, such a means includes two tension rollers <NUM> and <NUM>, wherein the actinic radiation-transparent substrate <NUM> is fed over one tension roller <NUM>, under the dam roller <NUM>, and over the other tension roller <NUM>. This configuration allows the tension rollers <NUM> and <NUM> to be configured to apply force to the actinic radiation-transparent substrate <NUM> to maintain the substrate <NUM> in contact with the dam roller <NUM> as the actinic radiation-transparent substrate <NUM> is conveyed through the apparatus. In the apparatus shown in <FIG>, the tension rollers are disposed adjacent to the dam roller <NUM> such that the actinic radiation-transparent substrate <NUM> is in contact with over <NUM> percent of the circumference of the dam roller <NUM> to further assist in minimizing leakage of the composition <NUM> off the actinic radiation-transparent substrate <NUM>.

In use, the apparatus <NUM> operates similarly to the apparatus <NUM> of <FIG> described above, including that as the substrate <NUM> continues to be driven from an unwind roller <NUM> (as well as over the first tension roller <NUM>, under the dam roller <NUM>, and over the second tension roller <NUM>) to the means for conveying <NUM> (e.g., a wind roller as shown in <FIG>). Further, in certain embodiments, the formed adhesive (e.g., <NUM>, <NUM>) is irradiated by one or more second irradiation sources <NUM> to post-cure the adhesive prior to winding up the substrate <NUM>. An air knife <NUM> optionally directs air towards the major surface <NUM> of the substrate <NUM> to assist in removing the composition <NUM> remaining on the major surface <NUM> of the substrate <NUM> that was not polymerized to form an adhesive by irradiation from the actinic irradiation source <NUM>. The excess composition <NUM> is preferably returned to the containment area defined by the dam roller <NUM>. Once a formed adhesive (e.g., the adhesive <NUM> and the adhesive <NUM>) reaches the wind roller <NUM>, the web of actinic radiation transparent substrate <NUM> is wound up.

Referring to <FIG>, a schematic of an apparatus <NUM> for use in exemplary methods of the present disclosure is provided. The apparatus includes at least two rollers <NUM> and <NUM> (at least one of which is configured to convey an actinic radiation-transparent substrate <NUM>), and an irradiation source <NUM> configured to direct actinic radiation through the actinic radiation-transparent substrate <NUM> at predetermined dosages at predetermined locations. The apparatus <NUM> further includes a means for depositing <NUM> a composition <NUM> onto a major surface <NUM> of the actinic radiation-transparent substrate <NUM> and a means for conveying <NUM> the actinic radiation-transparent substrate <NUM> or the irradiation source <NUM> with respect to each other. The means for depositing <NUM> comprises a die configured to dispense the composition <NUM> on the major surface <NUM> of the substrate <NUM>. In such embodiments, the composition <NUM> is preferably sufficiently viscous to remain on the major surface <NUM> of the substrate <NUM> without leaking off of the side edges of the substrate <NUM>. The actinic radiation-transparent substrate <NUM> is often a consumable material obtained separately from the apparatus <NUM> as opposed to being a component of the apparatus. Optionally, an air knife <NUM> configured to remove nonpolymerized composition <NUM> from the substrate <NUM> where one or more adhesives <NUM> and <NUM> are formed is provided with the apparatus <NUM>.

A further optional component of the apparatus <NUM> is a blade <NUM> that slices portions of the substrate <NUM> on which one or more adhesives (e.g., <NUM> and and/or <NUM>) are disposed. In the embodiment shown in <FIG>, a stack <NUM> of pieces of substrate <NUM> comprising one or more formed adhesives is illustrated. In an alternate embodiment, the substrate <NUM> on which one or more adhesives (e.g., <NUM> and/or <NUM>) are formed are wound up on a wind roll (not shown).

In certain embodiments, in use the apparatus shown in <FIG> is operated as follows: A die <NUM> deposits a composition <NUM> on a major surface <NUM> of an actinic radiation-transparent substrate <NUM>. An irradiation source <NUM> directs radiation through the actinic radiation-transparent substrate <NUM> at one or more predetermined dosages at one or more predetermined locations. The composition <NUM> that has been irradiated at least partially polymerizes, forming at least one adhesive, such as the adhesive <NUM> and the adhesive <NUM>, shown in <FIG>. For example, the adhesive <NUM> comprises a variation in width as compared to the adhesive <NUM>, as a result of the specific irradiation provided by the irradiation source <NUM>. A means for conveying <NUM> the actinic radiation-transparent substrate <NUM> drives a web of the actinic radiation-transparent substrate <NUM> over a roller <NUM> to allow gravity to begin separating the composition <NUM> that was not polymerized to form an adhesive (e.g., <NUM> and <NUM>). As the substrate <NUM> continues to be driven from a first roller <NUM> to a second roller <NUM>, an air knife <NUM> directs air towards the major surface <NUM> of the substrate <NUM> to assist in removing the composition <NUM> remaining on the major surface <NUM> of the substrate <NUM>. The excess composition <NUM> is preferably deposited in a container <NUM> for recycling or reuse. Once a particular section of the substrate <NUM> holding at least one formed adhesive (e.g., the adhesive <NUM> and/or the adhesive <NUM>) reaches the blade <NUM>, the blade <NUM> is employed and that portion of actinic radiation transparent substrate <NUM> is sliced off (and optionally added to a stack <NUM> of substrate <NUM> pieces each comprising at least one formed adhesive <NUM>.

Referring to each of <FIG>, the actinic radiation-transparent substrate comprises glass (e.g., in any of <FIG>) or a polymeric material (e.g., in any of <FIG>). When the actinic radiation-transparent substrate comprises a polymeric material, the substrate usually comprises a polymeric material selected from polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, cycloolefin films, poly(methyl methacrylate), or combinations thereof. When the actinic radiation-transparent substrate comprises glass, the substrate usually comprises a glass selected from sodium borosilicate glass, soda-lime glass, and quartz glass. In certain embodiments, the substrate comprises a multilayer construction, for instance a polymeric sheet, an adhesive layer, and a liner. In embodiments in which the adhesive is intended to be transferred from the multilayer construction to another surface or substrate, the multilayer construction comprises a coating (e.g., a release coating) upon which the integral adhesive is disposed.

Each of <FIG> referred to a means for conveying an actinic radiation-transparent substrate or an irradiation source with respect to each other. The means for conveying generally includes mechanical means as known in the manufacturing arts, such as a motor, a servo motor, a stepper motor, or any combinations thereof. Often, a motor ultimately drives one or more rollers, which convey a substrate (e.g., a cylinder or web of indefinite length) and/or the irradiation source.

Referring to each of <FIG>, the actinic radiation is typically provided by an irradiation source that is a digital light projector (DLP) with a light emitting diode (LED), a DLP with a lamp, a laser scanning device with a laser, a liquid crystal display (LCD) panel with a backlight, a photomask with a lamp, or a photomask with an LED. More particularly, a schematic is provided in <FIG> of a DLP with an LED or lamp, schematics are provided in <FIG> and <FIG> of a photomask with a lamp or LED, a schematic is provided in <FIG> of an LCD panel with a backlight, and a schematic is provided in <FIG> of a laser scanning device with a laser.

Referring now to <FIG>, a schematic is provided of an irradiation source <NUM> for use in exemplary methods of the present disclosure, comprising a DLP <NUM> with an LED or a lamp <NUM> (<NUM> represents either an LED or a lamp). The DLP <NUM> includes a plurality of individually movable reflectors, such as first reflector <NUM>, second reflector <NUM>, and third reflector <NUM>. Each reflector is positioned at a specific angle to direct irradiation from the LED or lamp <NUM> towards a predetermined location of a composition <NUM> disposed on a major surface <NUM> of an actinic radiation-transparent substrate <NUM>. In use, the intensity and duration of the irradiation from the LED or lamp <NUM> will impact the depth of cure (e.g., polymerization) of the composition <NUM> in a direction normal to the major surface <NUM> of the substrate <NUM> upon formation of one or more adhesives <NUM> and <NUM>. For instance, one portion 1017b of integral adhesive <NUM> has a greater thickness than another portion 1017a of the same integral adhesive <NUM>. This may be achieved by irradiating the portion 1017b with a greater dosage than the portion 1017a is irradiated. In contrast, adhesive <NUM> has a single thickness across its width due to receiving the same dosage across its width. A benefit of employing a DLP is that the individual reflectors are readily adjustable (e.g., using computer controls) to change the irradiation location and dosage and thereby the shape of the resulting formed adhesives, as needed without requiring a significant equipment alteration. DLPs are well-known in the art, for instance and without limitation, the apparatuses described in <CIT>), <CIT>), <CIT>), <CIT>), <CIT>), <CIT>), and <CIT>). Suitable DLPs are commercially available, such as from Texas Instruments (Dallas, TX). As indicated above, either an LED or a lamp may be employed with a DLP. Suitable lamps may include a flash lamp, a low pressure mercury lamp, a medium pressure mercury lamp, and/or a microwave driven lamp. The skilled practitioner can select a suitable LED or lamp light source to provide the actinic radiation required to initiate polymerization for a particular polymerizable composition, for instance, the UV LED CBT-<NUM>-UV, available from Luminus Inc. (Sunnyvale, CA).

Referring now to <FIG> and <FIG>, schematics are provided including an irradiation source <NUM> comprising at least one photomask 1170a and 1170b with an LED or a lamp <NUM> (<NUM> represents either an LED or a lamp), for use in exemplary methods of the present disclosure. A lens <NUM> having a convex surface <NUM> is employed with the LED or lamp <NUM> to diffuse the irradiation across at least a portion of the one or more photomasks 1170a and 1170b. As shown in <FIG>, a first photomask 1170a is employed to direct irradiation from the LED or lamp <NUM> towards a predetermined location of a composition <NUM> disposed on a major surface <NUM> of an actinic radiation-transparent substrate <NUM>. In use, the intensity and duration of the irradiation from the LED or lamp <NUM> will impact the depth of cure (e.g., polymerization) of the composition <NUM> in a direction normal to the major surface <NUM> of the substrate <NUM> upon formation of one or more adhesives <NUM> and <NUM>. For instance, one portion 1117b of integral adhesive <NUM> has a greater thickness than another portion 1017a of the same integral adhesive <NUM>. This may be achieved by employing more than one photomask. For instance, referring to <FIG>, a photomask 1170a is shown in which a plurality of portions 1171a are provided through which irradiation can be directed to cure the composition <NUM>. Referring now to <FIG>, a second photomask 1170b is shown in which one portion 1171b is provided through which irradiation can be directed to further cure the composition <NUM>. In the illustrated embodiment, the portion 1117b has a greater thickness than the portion 1117a due to being irradiated twice; once using the first photomask 1170a and once using the second photomask 1170b; resulting in irradiation of the portion 1117b with a greater dosage than the portion 1117a. In contrast, adhesive <NUM> has a single thickness across its width due to receiving the same dosage across its width by exposure to irradiation through just the first photomask 1170a. While the photomasks in <FIG> and <FIG> are shown as having opaque and transparent portions, the skilled practitioner will appreciate that photomasks including greyscale may be employed to achieve gradients in cure in different locations of the composition. Suitable photomasks are commercially available, for instance, NanoSculpt Photomasks from Infinite Graphics (Minneapolis, MN). Similar to using a DLP, either an LED or a lamp may be employed with a photomask.

Referring to <FIG>, a schematic is provided of an irradiation source <NUM> comprising a digital photomask <NUM> (e.g., a LCD with a backlight <NUM>), wherein the backlight comprises an LED or a lamp <NUM> (<NUM> represents either an LED or a lamp), for use in exemplary methods of the present disclosure. A lens <NUM> having a convex surface <NUM> is employed with the backlight <NUM> to diffuse the irradiation across at least a portion of the digital photomask <NUM>. In use, the intensity and duration of the irradiation from the backlight <NUM> will impact the depth of cure (e.g., polymerization) of the composition <NUM> in a direction normal to the major surface <NUM> of the substrate <NUM> upon formation of one or more adhesives <NUM> and <NUM>. For instance, one portion 1217b of integral adhesive <NUM> has a greater thickness than another portion 1217a of the same integral adhesive <NUM>. This may be achieved by irradiating the portion 1217b with a greater dosage than the portion 1217a is irradiated. In contrast, adhesive <NUM> has a single thickness across its width due to receiving the same dosage across its width. A benefit of employing a digital photomask is that the individual pixels are readily adjustable (e.g., using computer controls) to change the irradiation location and dosage and thereby the shape of the resulting formed adhesives, as needed without requiring a significant equipment alteration. Suitable LCDs are commercially available, for instance, the LCD LQ043T1DG28, available from Sharp Corporation (Osaka, Japan).

Referring to <FIG>, a schematic is provided of an irradiation source <NUM> comprising a laser scanning device <NUM> with a laser <NUM>, for use in exemplary methods of the present disclosure. The laser scanning device <NUM> includes at least one individually movable mirror. Each mirror is positioned at a specific angle to direct irradiation from the laser <NUM> towards a predetermined location of a composition <NUM> disposed on a major surface <NUM> of an actinic radiation-transparent substrate <NUM>. In use, the intensity and duration of the irradiation from the laser <NUM> will impact the depth of cure (e.g., polymerization) of the composition <NUM> in a direction normal to the major surface <NUM> of the substrate <NUM> upon formation of one or more adhesives <NUM> and <NUM>. For instance, one portion 1317b of integral adhesive <NUM> has a greater thickness than another portion 1317a of the same integral adhesive <NUM>. This may be achieved by irradiating the portion 1317b with a greater dosage than the portion 1317a is irradiated. In contrast, adhesive <NUM> has a single thickness across its width due to receiving the same dosage across its width. A benefit of employing a laser scanning device is that the individual mirror(s) are readily adjustable (e.g., using computer controls) to change the irradiation location and dosage and thereby the shape of the resulting formed adhesives, as needed without requiring a significant equipment alteration. Suitable laser scanning devices are commercially available, such as the JS2808 Galvanometer Scanner from Sino-Galvo (Beijing) Technology Co. (Beijing, China). The skilled practitioner can select a suitable laser to provide the actinic radiation required to initiate polymerization for a particular polymerizable composition, for instance, the CUBE <NUM>-100C Diode Laser System from Coherent Inc. (Santa Clara, CA).

Accordingly, any of the above irradiation sources of the present disclosure are suitable for use in each of the apparatuses of the disclosed embodiments herein. It is an advantage of these irradiation sources that they are readily configured to provide one or more predetermined dosages of irradiation at one or more predetermined locations, allowing the manufacture of adhesives having variations in size and shape, particularly in thickness normal to a substrate.

These Examples are merely for illustrative purposes and are not meant to be overly limiting on the scope of the appended claims. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Table <NUM> provides a role and a source for materials used in the Examples below:.

An apparatus for the continuous additive manufacturing of adhesives was constructed as generally depicted in <FIG>. The actinic radiation transparent substrate <NUM> was constructed from an Optically Clear Cast Acrylic Tube, <NUM> inches (<NUM> centimeters (cm)) outer diameter x <NUM>-<NUM>/<NUM> inches (<NUM>) inner diameter, cut to a length of <NUM> inches (<NUM>), obtained as item 8486K735 from McMaster-Carr, Chicago, IL, which was wrapped with a clear PET silicone release liner, type RF12N in <NUM> mil (<NUM> micrometer) thickness, available from SKC Haas, Seoul, Korea. Thus the siliconized side of the release liner formed the major surface <NUM> of the actinic radiation transparent substrate <NUM>.

Side walls made from flat cast acrylic sheet with a <NUM> inch (<NUM>) center hole and smaller access holes were inserted into the Clear Cast Acrylic Tube. Bearings with an outer diameter of <NUM> inches and an inner diameter of <NUM> inch were inserted into the <NUM> inch (<NUM>) holes, allowing The Clear Cast Acrylic Tube to rotate around a <NUM> inch (<NUM>) diameter, stationary, hollow steel tube. The steel tube was attached to a frame constructed from extruded aluminum. A drive system was constructed from a 3D printed cogwheel that was attached to the acrylic side wall, and a matching cogwheel on a 12V DC gear motor, model ZGA25RP83i manufactured by Wenzhou Zhengke Electromotor Co. , Ltd, Yueqing, China, which was mounted to the extruded aluminum frame.

A <NUM> hole was drilled at the center of the steel tube, and <NUM> LEDs (One LED emitting <NUM> UV light, model UV3TZ-<NUM>-<NUM>, and one LED emitting <NUM> UV light, model UV3TZ-<NUM>-<NUM>, both available from Bivar Inc, Irvine, CA) with <NUM> cable leads and a <NUM> ohm resistor were inserted through the hole and mounted to the stationary hollow steel tube with help of small acrylic bars. The LEDs were facing downwards inside of the Clear Cast Acrylic Tube, with about <NUM> distance from the inner surface of the tube.

The DC Motor and the <NUM> LEDs were connected to an Arduino R3 microcontroller with Arduino Motor Shield, available from SparkFun Electronics, Niwot, CO. The microcontroller was programmed to rotate the Clear Cast Acrylic Tube approximately <NUM> degrees, then to stop and light up the LEDs for <NUM> seconds, the program was set to repeat this sequence for a total of <NUM> times.

A container <NUM> with the base plate dimension of <NUM> inches (<NUM>) by <NUM> inches (<NUM>) and <NUM> inch (<NUM>) tall side walls was constructed from Optically Fluorescent Cast Acrylic, <NUM>/<NUM>" Thick, Amber, available as 85635K471 from McMaster-Carr, Chicago, IL, and placed on a lab jack under the Clear Cast Acrylic Tube.

A "Super Efficient Compressed-Air Air Knife, Aluminum, <NUM>" Air Slot Width", available as item 6069K12 from McMaster-Carr, Chicago, IL, was fitted to the frame, so that during the rotation of the drum it blows excess composition material from the major surface <NUM> back into the container <NUM>.

A UV Intensity Analyzer, Model <NUM>, from OAI Instruments, San Jose, CA, was used to measure the intensity and energy of the LEDs at the major surface <NUM>. The <NUM> broad band sensor was attached to the Analyzer, and the sensor surface was centered under the LED, with the sensor housing touching the major surface <NUM>. For the <NUM> LED an intensity of <NUM> mW/cm<NUM> and an energy dosage of <NUM> mJ/cm<NUM> was measured for the <NUM> second illumination. For the <NUM> LED an intensity of <NUM> mW/cm<NUM> and an energy dosage of <NUM> mJ/cm<NUM> was measured for the <NUM> second illumination.

An actinic radiation polymerizable composition was prepared by charging a <NUM> amber glass jar with <NUM> AA, <NUM> iOA and <NUM> iBOA, <NUM> HDDA, <NUM> TINOPAL OB CO, <NUM> BHT and <NUM> IRGACURE TPO. The jar was sealed and rotated on a laboratory bench top roller MX-T6-S at approximately <NUM> RPM for <NUM> hours.

The composition was poured into the container <NUM> of the experimental apparatus and the container was lifted with help of the lab jack, so that the composition contacted the major surface <NUM> right underneath the LEDs.

The experimental apparatus was switched on and went through the sequence of rotating the drum and switching on the LEDs.

It was observed that at the spots that were illuminated by the LEDs dots of cured adhesive composition were formed. As the drum rotated, these dots emerged from the liquid composition and the excess liquid composition ran off the major surface <NUM>, back into the container <NUM>. The dots were approximately <NUM> in diameter and <NUM> in thickness.

A microscopy glass slide was pressed onto the dots, and it was observed that they adhered to the glass slide. The dots then were post cured for <NUM> minutes in an Asiga Flash UV post cure chamber, available from Asiga, Anaheim Hills, California, USA. This post cure chamber contains four 9W fluorescent bulbs with a peak wavelength of <NUM>, arranged approximately <NUM> inches (<NUM>) from a <NUM> inch (<NUM>) by <NUM> inch (<NUM>) base plate. The UV intensity was measured using the UV Intensity Analyzer, Model <NUM>, from OAI Instruments, San Jose, CA, with the <NUM> broad band sensor. A UV intensity of approximately <NUM> mW/cm<NUM> was found throughout the base plate.

After the post cure the dots were touched, and they felt sticky and adhered to the finger like a pressure sensitive adhesive. A piece of paper was pressed on the dots and it was observed that the paper and the glass slide were adhered together.

Claim 1:
A method of manufacturing adhesives comprising:
obtaining an actinic radiation-polymerizable adhesive precursor composition disposed on a major surface of an actinic radiation-transparent substrate;
irradiating a first portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a first irradiation dosage to form a first adhesive;
moving the actinic radiation-transparent substrate; and
irradiating a second portion of the actinic radiation-polymerizable adhesive precursor composition through the actinic radiation-transparent substrate for a second irradiation dosage to form a second adhesive,
wherein the first adhesive and the second adhesive are individual adhesives separated from each other by approximately the distance the actinic radiation-transparent substrate was moved.