摘要:
A process for making a microneedle array master comprises: (a) providing a photoreactive composition, the photoreactive composition comprising: (1) at least one reactive species that is capable of undergoing an acid- or radical-initiated chemical reaction, and (2) at least one multiphoton photoinitiator system; and (b) imagewise exposing at least a portion of the composition to light sufficient to cause simultaneous absorption of at least two photons, thereby inducing at least one acid- or radical-initiated chemical reaction where the composition is exposed to the light, the imagewise exposing being carried out in a pattern that is effective to define at least the surface of a plurality of microneedles. The microneedles may be solid and the outer surface of the microneedles may be characterized by at least one concave area. The master may be used to fabricate a tool for replication.
摘要:
A process for making a microneedle array master comprises: (a) providing a photoreactive composition, the photoreactive composition comprising: (1) at least one reactive species that is capable of undergoing an acid- or radical-initiated chemical reaction, and (2) at least one multiphoton photoinitiator system; and (b) imagewise exposing at least a portion of the composition to light sufficient to cause simultaneous absorption of at least two photons, thereby inducing at least one acid- or radical-initiated chemical reaction where the composition is exposed to the light, the imagewise exposing being carried out in a pattern that is effective to define at least the surface of a plurality of microneedles. The microneedles may be solid and the outer surface of the microneedles may be characterized by at least one concave area. The master may be used to fabricate a tool for replication.
摘要:
The present invention is directed to a method of forming a mold for use in making molded articles having a plurality of microprojections. Additionally, the present invention provides a method of forming a molded article having a plurality of microprojections. In one aspect, a mold workpiece is provided, a tool having a tip with a shape corresponding to the microprojection, wherein the hardness of the tool is greater than that of the mold workpiece, is pressed into the mold workpiece and removed, thereby creating a mold with a microprojection cavity suitable for use in making the molded article.
摘要:
An ultrasonic-assisted injection molding system and method for making precisely-shaped articles. A source of ultrasonic energy is positioned to apply vibrational energy to a mold cavity connected to at least one gate in flow communication with a source of molten (co)polymer. The mold is heated to a temperature of 104-116° C., and the molten (co)polymer is injected into the mold cavity. After cooling the mold until the molten (co)polymer within the gate has solidified, ultrasonic energy is applied to the mold without remelting the solidified (co)polymer within the gate until the temperature increases to 116-122° C., thereby substantially relieving flow induced stresses. The mold is then cooled until the temperature decreases to 101-107° C., and is thereafter heated until the temperature increases to 116-122° C., thereby substantially relieving any thermally induced stresses. The mold is cooled until the molten (co)polymer has solidified, thereby forming a precision molded plastic optical element.
摘要:
Injection molding parts onto a carrier web located between mold halves, each mold half having a cavity, resulting in molded articles having parts on both sides of the carrier web. Polymer flow into the cavities is assisted by application of ultrasonic energy to the mold. After the molding operation, mold halves are separated, and the carrier web is advanced, or indexed, to a next position for another molding sequence. Articles produced include lenses with part of the carrier web between lens halves, and a carrier web bearing an array of molded parts.
摘要:
The present invention is a system for molding a gasket to a membrane electrode assembly. The system comprises a cavity defined at least in part by closable mold blocks, at least one injection gate for injecting gasket material into the cavity, a mount for retaining the membrane electrode assembly adjacent to the cavity, and a mold insert independently movable relative to the closable mold blocks for applying pressure to the membrane electrode assembly retained on the mount.
摘要:
An article bearing a flow field such as a distribution plate for use in a fuel cell is provided. The active portion of the article, i.e., the portion of the article bearing the flow field, comprises at least two subsections; a first central subsection and a second peripheral subsection; wherein channels within the first subsection have a cross-sectional profile that differs from that of channels within the second subsection. Typically, channels of the first subsection have lesser depth, greater draft or greater ratio of draft to depth. In addition, an article bearing a flow field is provided where the flow field comprises at least two channel segments which differ in draft. In addition, an article bearing a flow field is provided where the flow field comprises at least one channel segment comprising first and second channel walls which differ in draft.
摘要:
A molded article comprising at least one chain of microneedle arrays wherein adjacent arrays in the chain are interconnected by integrally formed runners. Such a molded article may further comprise two or more chains of microneedle arrays, wherein adjacent chains are interconnected to each other by integrally formed runners. Also, methods of making molded articles and positioning them for delivery to a patient.
摘要:
An ultrasonic-assisted injection molding system and method for making precisely-shaped articles. A source of ultrasonic energy is positioned to apply vibrational energy to a mold cavity connected to at least one gate in flow communication with a source of molten (co)polymer. The mold is heated to a temperature of 104-116° C., and the molten (co)polymer is injected into the mold cavity. After cooling the mold until the molten (co)polymer within the gate has solidified, ultrasonic energy is applied to the mold without remelting the solidified (co)polymer within the gate until the temperature increases to 116-122° C., thereby substantially relieving flow induced stresses. The mold is then cooled until the temperature decreases to 101-107° C., and is thereafter heated until the temperature increases to 116-122° C., thereby substantially relieving any thermally induced stresses. The mold is cooled until the molten (co)polymer has solidified, thereby forming a precision molded plastic optical element.