WO2006032493A2 - Appareil et procede permettant d'imprimer des microstructures - Google Patents

Appareil et procede permettant d'imprimer des microstructures Download PDF

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Publication number
WO2006032493A2
WO2006032493A2 PCT/EP2005/010246 EP2005010246W WO2006032493A2 WO 2006032493 A2 WO2006032493 A2 WO 2006032493A2 EP 2005010246 W EP2005010246 W EP 2005010246W WO 2006032493 A2 WO2006032493 A2 WO 2006032493A2
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WO
WIPO (PCT)
Prior art keywords
curing
printing
ispr
surface relief
cylinder
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PCT/EP2005/010246
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English (en)
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WO2006032493A3 (fr
Inventor
Johannes Matthiesen
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Securis Limited
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Publication of WO2006032493A2 publication Critical patent/WO2006032493A2/fr
Publication of WO2006032493A3 publication Critical patent/WO2006032493A3/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/10—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation for articles of indefinite length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0888—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using transparant moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
    • B29C59/04—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing using rollers or endless belts
    • B29C59/046—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing using rollers or endless belts for layered or coated substantially flat surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
    • B29C2035/0822—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using IR radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
    • B29C2035/0827—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using UV radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/16—Cooling
    • B29C2035/1658—Cooling using gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
    • B29C59/022—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor
    • B29C2059/023—Microembossing

Definitions

  • the invention relates to an apparatus and process for the manufacture of surface relief microstructures e.g. holograms.
  • a more recently developed method is that of in-situ polymerization replication (ISPR).
  • ISPR in-situ polymerization replication
  • a liquid polymer or resin usually deposited on a substrate such as a polymer film or web, is cast or molded against the microstructure to be replicated e.g. holographic image or optically variable effect profile, in a continuous fashion.
  • the molded profile is retained in the polymer or resin on or after removal from the microstructure mold by use of a curing stage. Examples of this approach are described in United States Patent Nos. 3,689,346, 4,758,296, 4,840,757, 4,933,120, 5,003,915, 5,085,514 and in DE-A-4, 132,476, WO88/09252 and WO94/18609.
  • the microstructure to be molded is provided as a relief in a metal surface on a rotary cylinder. They all utilize radiation curable media as the liquid polymer or resin media for casting and therefore this technology is sometimes referred to as UV
  • the curing of the radiation curable media is achieved by the use of a UV source that is located within the bore of a hollow quartz cylinder that is carrying the microstructu re relief image to be molded.
  • the relief image is formed in a polymer sleeve that has been placed or cast on the outer surface of the quartz cylinder.
  • the polymer sleeve Is substantially transparent to the UV radiation that is used to cure the cast radiation curable resin.
  • the microstructure relief image is cast on the cylinder using UV curable resin system.
  • the thickness of the cast layer containing the surface relief microstructure is in the range from 3 ⁇ m up to 300 ⁇ m.
  • the surface relief microstructure located on the quartz cylinder is a cured organic material it is relatively soft compared to the metal surfaces used in more conventional other ISPR processes.
  • ISPR processes are attractive processes as they are web based and lend themselves to continuous/semi-continuous operations for bulk manufacture of surface relief structures.
  • One of the enduring problems with web based processes is that there is always a limit to the speed at which the web can be processed and this limit usually manifests itself in the limit at which acceptable quality may be achieved or the limit of the casting technology used; this is usually the maximum curing speed for the radiation curing resin to be cast.
  • UV curing technologies are known in the printing industry that can run at web speeds in excess of 100 meters per minute.
  • Image quality is critically important in many applications as the resultant application relies upon good quality optical effects which are directly related to the quality of the transferred image, respectively microstructure of trie refraction grating.
  • many applications of ISPR technology require that the apparatus for ISPR is utilized in-line and in co-operation with other processes e.g. printing and finishing processes as used in the graphic arts industry.
  • a further challenge is to provide ISPR processes that may be easily controlled and implemented with the minimum degree of wastage of materials; this is especially important for in-line applications.
  • the present invention addresses these technical challenges by providing a new design of ISPR printing apparatus that is more flexible and compact compared to such prior art arrangements as that described for example in WO94/18609.
  • ISPR printing apparatus comprising a) mechanism for feeding a substrate through the apparatus, b) a coating station comprising a source of liquid curable resin and means for applying liquid resin from the source to a surface of the substrate, d) a printing/curing station comprising means for imprinting a surface relief microstructure into the surface of the applied resi n on the substrate, and means for curing the resin having surface relief microstructures imprinted therein such that these microstructures are retained in the cured resin, characterized in that, the apparatus is arranged such that the resin is applied to the top surface of the substrate; that the means for imprinting the surface relief microstructure comprises a hollow transparent cylinder having a surface relief microstructure and two nip rollers which contact the back surface of the substrate and which have an axis of rotation that is alo ng the same axis as the axis of rotation of the hollow transparent cylinder and trie means for curing the resin is a UV source located in the bore of the hollow transparent cylinder.
  • the ISPR printing apparatus further comprises a means for heating the substrate with uncured resin coated thereon, which is located between the coating station and the printing/curing station. It has been found that the heating station is advantageous when high web speeds are desired or when high viscosity resins are used to provide the resin coating. The heating station assists in ensuring that there is uniform flow-out of the thin resin layer after application to the top of the substrate.
  • One suitable heating means is a temperature controlled oven , tunnel or an IR heating station. If an IR heating station is used it may apply heat directly to the resin on the top surface of the substrate or it may apply heat to the back surface of the substrate or a combination of both methods. Preferably the heat is applied via an IR source to the resin on the top surface of the substrate, or by heated air.
  • the ISPR printing apparatus of the present invention further comprises a cooling station located proximate to the printing/curing station.
  • the temperature of the surfaces in the printing/curing station and the ambient temperature around the printing/curing station may be relatively high. Whilst this is tolerable for certain substrates and applications that use the ISPR printing apparatus in some applications the substrate may be heat sensitive.
  • the main source of heat is the UV lamps located in the bore of the quartz cylinder.
  • the cylinder itself is quartz, and heat builds up in the cylinder during use. Such relatively large increases in heat during use can also affect maintenance of surface relief microstructure quality during use of the ISPR printer.
  • the arrangement of the ISPR printing apparatus lends itself to easy access for efficient cooling and especially for the location of a cooling station proximate to the printing cylinder to enable cooling to be applied directly to the cylinder surface during use.
  • the cooling means is a bank of air coolers or fans located above the printing cylinder and between the guide rollers in the printing station. The present arrangement is such that in this orientation the cooling may be applied directly to the cylinder surface.
  • This surface cooling in combination with the inherent cooling associated with the UV lamp and an additional cool air flow inside the cylinder, being independent from the lamp and lamp housing cooling system and optionally the use of additional cooling beneath the printing cylinder, which impinges on the back of the substrate web, results in a significant reduction in the temperature of the printing station.
  • the temperature may be controlled to be within the range of 40 to 80 0 C and more preferably within the range of 40 to 5O 0 C. Without this effective additional cooling the temperatures may easily exceed 80 0 C.
  • a further benefit of the effective cooling of the surface relief microstructure on the cylinder is that this aids release of the cured resin from the surface of the cylinder; this enables higher web speeds to be achieved whilst maintaining image quality.
  • a further disadvantage with prior art ISPR printing equipment is that it has been difficult to provide high levels of UV energy at the point of contact between the surface relief microstructure of the cylinder and the uncured resin located on the substrate.
  • the printing cylinder is a solid material such as metal this is because the UV curing station is usually located after the printing station; this means that the surface relief microstructure surface of the cylinder is released from the resin before it is cured, with inherent problems in resulting image quality.
  • the UV source is located such that irradiation occurs through the back of the transparent substrate surface and into the uncured resin whilst the resin is in contact with the printing cylinder.
  • the present arrangement it is now possible to utilize effectively and easily at least two UV sources; one located within the bore of the hollow cylinder and the other located beneath the cylinder and proximate to the back surface of the web as it passes around the hollow cylinder.
  • the uncured resin when in contact with the surface relief microstructure of the cylinder is irradiated from above and below through the transparent substrate.
  • two additional UV sources outside of the hollow cylinder in the printing station.
  • the benefit of additional UV irradiation at the contact point between the uncured resin and the surface relief microstructure on the hollow cylinder is that the resin may be cured faster and more thoroughly when in contact with the hollow cylinder surface relief ensuring high image quality and faster web speeds.
  • the present invention provides for an ISPR printing apparatus, which comprises at least two UV sources associated with the printing/curing station.
  • One of the UV sources is located within the bore of a hollow printing cylinder and the second is located beneath the cylinder irradiating the resin in contact with the surface relief microstructure of the cylinder through the transparent substrate upon which the resin is coated.
  • the ISPR printing apparatus of the present invention enables useful increases in web speed to be achieved via the use of various additional components or stations as described above there is still the need for additional means of increasing web speed whilst maintaining the quality of the surface relief microstructure image. It has been found that if a UV pre-curing station is utilized in the ISPR printing apparatus to partially cure the curable resin before it enters the printing/curing station then it is possible to increase web speed without loss of quality of the microstructures produced.
  • the station for applying the resin material into which the microstructure is to be cast is located in advance of the printing/curing station, and a UV pre-curing station is utilized, which partially cures the radiation curing resin before the image is cast into the resin, then the overall speed of the imaging line may be increased without loss of image resolution.
  • the radiation curable material has been partially cured prior to the imaging process yet despite this the image is still transferred into the partially cured resin with high quality.
  • the present invention provides for an ISPR printing apparatus further comprising a UV pre-curing station.
  • the ISPR printing apparatus may also utilize means for applying pressure to the first nip roller of the printing/curing unit.
  • additional pressure at this nip roller forces the partially cured resin coating against the surface relief microstructure on the printing cylinder and this pressure aids in deforming the partially cured resin in order to ensure that it conforms to the profile of the surface relief microstructure.
  • additional pressure at this point enables the ISPR printer to be run at higher web speeds as the partially cured coating will be imprinted at higher speeds than would be achieved without the additional pressure.
  • the exact pressure used will depend on the nature of the resin used and the extent of partial curing and thus the deformability of the partially cured resin.
  • the present invention therefore provides a process for the manufacture of a surface relief microstructure by ISPR, which process comprises the steps of:
  • a ISPR printing apparatus comprising:
  • the present invention provides a continuous process for the manufacture of a surface relief microstructure which process comprises:
  • the apparatus, methods and processes of the present invention may be used in combination with any of the known ISPR methods and apparatus in the art such as those described in United States Patent Nos. 3,689,346, 4,758,296, 4,840,757, 4,906,315 4,933,120, 5,003,915, 5,085,514 6,214,443 6,344,245 6,436,483 and in DE-A-4, 132,476, EP 0,338,378, WO88/09252, WO94/18609, W 099/38704; the whole contents of each of these foregoing reference are all hereby incorporated by reference.
  • the apparatus of the present invention further comprises a control unit which is capable of controlling the UV energy output of the pre-curing UV source and the UV source associated with the printing/curing station.
  • This control unit enables the energy of each UV source to be varied independently of each other or to be varied in a coordinated fashion.
  • the pre-curing station is set at the required energy to ensure full curing of the resin coating before the radiation curable liquid resin is applied to the substrate.
  • the UV source associated with the printing/curing station may be set at minimum power or at power that would be sufficient to ensure full curing of the radiation curable liquid resin. At this point the radiation curable liquid resin is applied to the substrate and is fully cured at the pre-curing station.
  • the substrate with fully cured coating then passes into the printing/curing station and passes through the station without having any surface relief microstructure imprinted into its surface. This is the start up phase of the ISPR printing apparatus. At this point the energy of the UV pre-curing station is reduced whilst either maintaining the optimum energy of the UV source associated with the printing/curing station or increasing its energy up to the optimum level for curing the resin. As the energy of the UV lamps are altered in this way the radiation cured coating leaving the pre-curing station becomes partially cured and on passage to the printing/curing station is able to be imprinted with the surface relief microstructure and fully cured in the imprinted state. When the printing run is complete the process is reversed to ensure that no uncured resin passes through the printing/curing station. This technique may be optimized to provide partially cured resin to the printing/curing station that on imprinting and full curing provides high quality surface relief microstructures in the cured resin at optimum speed.
  • the ISPR printing apparatus may further comprise a UV-post-curing unit with or without a heating unit, or just an IR-heating unit, or combined UV/IR, which may be especially recommanded in order to support and speed up the curing of typically post curing cationic varnish systems.
  • This post curing unit may be used when the coated substrate leaving the printing/curing unit although successfully imprinted is not full cured. The post curing unit ensures that the coating is fully cured.
  • the post-curing unit comprises a heating unit e.g. an IR heating unit or oven then this may be useful in ensuring full cure of resin coatings based on cationic systems as these systems are living polymerizations that are accelerated to completion by the action of heat.
  • the apparatus of the present invention may be an off-line or stand alone unit or in an alternative embodiment this may be an in-line or integrated system with other further conventional printing, laminating, cutting, slitting and other converting stations as part of an integrated manufacturing process.
  • the apparatus and processes of the present invention may be configured and used to provide partial holographic printing of a web based substrate. This may be achieved by partially printing the radiation curable lacquer as for example graphic elements onto the web based substrate and replicating the microstructure only in that areas where the radiation curable lacquer has been printed.
  • the radiation curable composition used for the manufacture of the cylinder surface and for the radiation curable lacquer will be a composition that is one of three types.
  • the first are free radical polymerized or cured resin systems which are unsaturated resins or monomers, pre-polymers, oligomers etc that contain vinyl and/or acrylate unsaturation for example and which polymerize and/or cross-link through use of a photo initiator activated by the radiation source employed e.g. UV. These are typically referred to as rad ⁇ cal systems.
  • the second is cationic polymerizable or cured resins in which ring opening (e.g.
  • epoxy rings is effected using photoinitiators or catalysts wh ich generate ionic entities under the radiation source employed e.g. UV.
  • the ring opening is followed by cationic polymerization and/or intermolecular cross- linking.
  • resins that contain one or more groups with vinyl unsaturation are typically referred to as cationic systems.
  • the third type is a hybrid cured systems in which both free radical cured resins and cationic cured resins are combined. These systems are typically referred to as radical/cation ⁇ c systems or combined systems.
  • Typical resins useful in UV curable coatings are styrented polyesters and acrylics, such as vinyl copolymers of various monomers and glycidyl methacrylate reacted with acrylic acid, isocyanate prepolymers reacted with an hydroxyalkyl acrylate, epoxy resins reacted with acrylic or methacrylic acid, and hydroxyalkyl acrylate reacted with an anhydride and subsequently reacted with an epoxy.
  • the radiation used to effect curi ng of the radiation curable medium will typically be UV radiation, alternatively or in combination the radiation source could include electron beam, visible, infra-red or higher wavelength radiation, depending upon the material, its absorbance and the process used.
  • the radiation sources useful in the apparatus and processes of the present invention include Electron Beam radiation units that are readily available and typically consist of a transformer capable of stepping up line voltage and an electron accelerator.
  • the electrons are generated from a point source filament and then scanned electromagnetically like a television set to traverse the coated object.
  • the electrons are generated in a curtain from an extended filament which can irradiate the entire width of the surface without the need for scanning. While commercial machines are available with accelerating voltages of over a million electron volts, the range for this and similar coating applications is typically fro m 150-300 KV (kiloelectron volts).
  • UV curing stations that are well known in the art. It is within the scope of the present invention that the radiation sources may be both EB or both UV or any combination of UV and EB.
  • the cylinder comprising trie micro-structure is manufactured using a UV curable silicone resin or a two-part silicone elastomer.
  • the silicone compounds for use in the present invention are silicone compounds that contain either vinyl and/or acrylate unsaturation that may be co-polymerized or cross-linked via free radicals or they contain vinyl and/or oxirane functionality e.g. epoxy groups that may be incorporated into cationic polymerized systems via cationic coploymerization and/or cross-linking.
  • silicone compounds are known in the art and are commercially available.
  • Silicone compounds that may be incorporated via free radical mechanisms include products that are available from Degussa AG Goldschmidt Industrial Specialities and marketed under the trade name TEGO ® and as described in "UV Curable Silicones", S. Oestreich, paper presented at Radtech Europe Conference 2001 , held at Basel, Switzerland from 8 th to 10 th October 2001. Silicone compounds that may be incorporated by cationic polymerization mechanisms are commercially available from Rhodia-Silcones under the trade name SILCOLEASE ® and as described in "UV/EB Silicone Release Coating - Global Approach" J-M Frances et al, paper presented at Radtech Europe Conference 2001 , held at Basel, Switzerland from 8 th to 10 th October 2001.
  • the silicone compound may be utilized in the formulation for the radiation curable medium for the cylinder at any concentration. Preferably it is present in the formulation at a concentration of at least 1 wt% based on the total weight of composition, more preferably at least 2 wt%, even more preferably at least 3 wt% and most preferably at least 5 wt%.
  • the silicone compound may be a complex oligomeric material and may constitute 100% of the polymerizable component of the formulation, the remainder of the formulation being made up of photoinitiators and/or other additives.
  • the surface relief microstructure is manufactured on a transparent hollow cylinder.
  • the cylinder may be manufactured from any material that is substantially transparent to UV radiation.
  • the cylinder may be manufactured from a polymer material or quartz. When quartz is used the cylinder may be manufactured from synthetic/processed or natural quartz. Preferably the cylinder is manufactured from synthetic/processed quartz.
  • the cylinder comprising the surface relief microstructure may be manufactured by the general process as described in WO94/18069.
  • an original surface relief microstructure e.g. hologram is prepared by well-known means. To produce the original hologram, an object is first recorded in a first hologram by standard off-axis recording techniques.
  • a Benton hologram is then recorded from the first hologram onto a surface relief medium such as photoresist, thus producing the original surface relief hologram.
  • the next step is the manufacture of the hologram master.
  • a hologram master may be made by any of various techniques. One well-known way technique is to electroform nickel onto the original surface relief hologram, thereby producing a reversed metal replica of the original. This master may then be used to manufacture the surface relief microstructure using the general process as described in WO94/18069.
  • an original surface relief microstructure e.g. hologram is prepared by well-known means.
  • an object is first recorded in a first hologram by standard off-axis recording techniques.
  • a Benton hologram is then recorded from the first hologram onto a surface relief medium such as photoresist, thus producing the original surface relief hologram.
  • the next step is the manufacture of the hologram master.
  • a hologram master may be made by any of various techniques.
  • One well-known way technique is to electroform nickel onto the original surface relief hologram, thereby producing a reversed metal replica of the original. This master may then be used to manufacture the cylinder with surface relief microstructure using the general process as described in WO94/18069 and as described above.
  • the radiation curable liquid coating or lacquer is a composition which comprises a radiation curable composition diluted with a solvent.
  • the radiation curable lacquer comprises up to 60% by weight of solvent with the balance being radiation curable composition.
  • the solvent may be any solvent that is compatible with the radiation curable composition and which may be removed after coating of the radiation curable lacquer on the substrate.
  • the solvent is a material which is not designed to react with the radiation curable components on radiation curing. Lacquers comprising solvents have relatively low viscosities e.g. water viscosities at ambient temperature and on application to the web based substrate provide relatively thin smooth and almost mirror like lacquer surfaces. The thickness is typically 1 to 2.5 ⁇ m.
  • apparatus and various processes according to the present invention utilize means for removing the solvent preferably by evaporation from the coated lacquer prior to contact with the cylinder comprisi ng surface relief microstructures. This evaporation may be achieved through use of for example a hot air drying tunnel.
  • apparatus and various processes of the present invention further comprise means for coating on the web based substrate that utilizes curtain coating.
  • curtain coating means that are capable of providing a relatively uniform thickness of from 1 to 80 ⁇ m to be achieved with a relatively smooth surface.
  • microstructure relief surface is used to mean holograms, diffractive patterns and any structure that may provide an optical effect.
  • the term also encompasses structures at the nanometer to micrometer scale that are not designed to provide optical effects.
  • Figure 1 is a schematic representation of an ISPR printing apparatus according to the present invention
  • Figure 2 is a schematic representation of an ISPR printing apparatus according to the present invention wherein the radiation curable liquid casting resin coating is heated with an IR source prior to entering the printing station,
  • FIG. 3 is a schematic representation of an ISPR printing apparatus according to the present invention which incorporates a cooling station proximate to the printing cylinder,
  • FIG. 4 is a schematic representation of an ISPR printing apparatus according to the present invention which incorporates additional UV sources within the printing/curing station,
  • Figure 5 is a schematic representation of an ISPR printing apparatus according to the present invention which incorporates a UV-pre- curing station in advance of the printing/curing station
  • Figure 6 is a schematic representation of an ISPR printing apparatus according to the present invention which incorporates a pre-curing station in advance of the UV-printing/curing station and a UV-post-curing station.
  • a roll (1) of plastic film substrate is unwound and passed through a coating station (2) that applies a curable resin (3) to the top surface (4) of the substrate.
  • This coated substrate then passes to the printing/curing station (5), which comprises a hollow quartz cylinder (6) upon which is located a layer comprising a surface relief microstructure (7), which is transparent to UV.
  • the coated substrate under tension is guided by guide rollers (8) and (9) around the cylinder (6) and passes through two nip sections provided by nip rollers (10) and (11), which are in contact with the back surface (12) of the substrate.
  • the cylinder and nip rollers (8) and (9) are in indirect contact with each other (the substrate is located between them) along an axis "X", which is horizontal in the apparatus of this embodiment.
  • the resin is imprinted with the surface relief microstructure and simultaneously cured by the action of the UV radiation, which passes through the transparent cylinder (6) and the layer (7) to cure the resin on the substrate thus ensuring that the surface relief microstructure is retained in the surface of the cured resin layer.
  • the layout of this apparatus is compact and highly adaptable for the inclusion of other stations and process features.
  • the ISPR printing apparatus shown is almost identical to that described in relation to Figure 1 , with the exception that an IR heating station (20) is located above the coated substrate (21) and between the coating station (22) and the printing/curing station (23).
  • the ISPR printing apparatus shown is almost identical to that described in relation to Figure 1 , with the exception that a cooling station (30) is located between guide rollers (31) and (32) and above the surface (33) of the printing cylinder (34). In this arrangement it is possible for the cooling station (30) to provide cooling air directly to the surface (33) of the printing cylinder (34) during use. Also shown is optional additional cooling station (35), which is located beneath the printing cylinder (34) and which cools the back surface (36) of the web substrate (37). An additional cool air flow is used from inside the cylinder, being independent from the lamp and the lamp housing cooling system.
  • the ISPR printing apparatus shown is almost identical to that described in relation to Figure 1 , with the exception that additional UV sources (40) and (41) are located between the nip rollers (42) and (43) and proximate to the back surface (44) of the polymer web (45).
  • additional UV sources (40) and (41) provide high intensity of UV irradiation to the contact region between the coated polymer web (45) and the surface relief microstructure (48) of the cylinder C47) between points A and B.
  • the ISPR printing apparatus shown is almost identical to that described in relation to Figure 1 , with the exception that there is a UV-pre-curing unit (50) located after the coating station (51) and before the printing/curing station (52).
  • the pre-curing unit (50) irradiates the radiation curable resin coated on the web substrate (53) so that it is at least partially cured before it enters the printing/curing station (52).
  • the pre-cure unit (50) will operate at full power to ensure full cure of the resin at start-up. This is in o rder to avoid uncured varnish closing and blocking the microstructure on the printing cylinder due to unsufficient curing energy during the start-up phase.
  • the UV pre-curing unit When the web substrate (53) is transparent to UV the UV pre-curing unit may be located below the web irradiating the UV curable resin through the substrate (53). It is preferred that the UV pre-curing unit (50) irradiates the surface of the UV curable resin.
  • the lamp of the UV pre-curing unit (50) and the printing/curing station UV lamp (54) may be controlled by the same control unit (not shown) so that their power outputs may be coordinated and balanced as described above.
  • the careful use of the pre-curing unit in combination with the main LJV curing unit of the cylinder enables the apparatus to operated cleanly so that after completion of the printing process with termination of UV lacquer coating the apparatus may be operated to ensure that all uncured UV lacquer is removed from the apparatus in what may be referred to as a "self-cleaning" mode of operation.
  • the ISPR printing apparatus shown is almost identical to that described in relation to Figure 1 , with the exception that there is a UV-pre-curing unit (60) located after the coating station (6"I) and before the UV-printing/curing station (62) and a UV-post-curing unit ⁇ 63).
  • a UV-pre-curing unit 60 located after the coating station (6"I) and before the UV-printing/curing station (62) and a UV-post-curing unit ⁇ 63).

Abstract

L'invention concerne des microstructures à relief de surface, telles que des hologrammes, pouvant être reproduites rapidement et avec précision sur une bande placée dans un appareil d'impression de reproduction par polymérisation in situ (ISPR). Ledit appareil comprend un certain nombre de stations équipées d'un premier étage de séchage par rayonnement qui sèche au moins partiellement un revêtement, et un second étage de séchage par rayonnement qui comprend également une surface d'estampage de microstructure qui fournit une microstructure au revêtement pouvant être partiellement séché à ladite lorsqu'il est en contact avec la surface d'estampage de ladite microstructure. D'autres stations comprennent des unités de chauffage, des unités de refroidissement, des unités de post-séchage et des sources U.V. secondaires associées à la surface d'estampage de microstructure. L'appareil d'impression ISPR est agencé afin de recevoir facilement et efficacement ces stations supplémentaires et fonctionne afin d'atteindre une vitesse maximum de bande tout en maintenant la qualité d'image.
PCT/EP2005/010246 2004-09-23 2005-09-20 Appareil et procede permettant d'imprimer des microstructures WO2006032493A2 (fr)

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Application Number Priority Date Filing Date Title
GB0421169A GB0421169D0 (en) 2004-09-23 2004-09-23 Apparatus and process for the printing of microstructures
GB0421169.4 2004-09-23

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WO2006032493A2 true WO2006032493A2 (fr) 2006-03-30
WO2006032493A3 WO2006032493A3 (fr) 2006-07-06

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WO2008061930A1 (fr) * 2006-11-21 2008-05-29 Ciba Holding Inc. Appareil et procédé pour fabriquer un produit de sécurité
WO2009062867A1 (fr) * 2007-11-15 2009-05-22 Basf Se Procédé pour produire une lamelle support d'image optiquement variable
CN102442054A (zh) * 2011-10-17 2012-05-09 谭日和 一种同步印刷压纹机
US8247386B2 (en) 2004-08-23 2012-08-21 Sylentis Sau Methods and compositions for the treatment of eye disorders with increased intraocular pressure
CN103395282A (zh) * 2013-06-28 2013-11-20 广东新优威印刷装备科技有限公司 一种镭射图案印刷装置
US20140061976A1 (en) * 2012-09-05 2014-03-06 Heidelberger Druckmaschinen Ag Method and apparatus for producing embossed structures in radiation-curing materials
CN103786423A (zh) * 2014-01-27 2014-05-14 虎彩印艺股份有限公司 一种圆压圆透明转印辊
US8993219B2 (en) 2011-06-21 2015-03-31 Basf Se Printing diffraction gratings on paper and board
EP2038124B1 (fr) 2006-06-27 2016-03-09 Giesecke & Devrient GmbH Procédé pour appliquer une microstructure, moule d'outil et objet doté d'une microstructure
EP2849809A4 (fr) * 2012-05-18 2016-06-22 Angelini Pharma Inc Appareil de désinfection de dispositifs portatifs
IT201800003900A1 (it) * 2018-03-22 2019-09-22 Raul Maria Orlandi Processo di microincisione di strutture nanometriche su inchiostri e lacche "uv" poste a rivestimento di pellicole plastiche o qualsiasi pellicola o film che possa essere spalmata con tali inchiostri o lacche

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Cited By (17)

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US8247386B2 (en) 2004-08-23 2012-08-21 Sylentis Sau Methods and compositions for the treatment of eye disorders with increased intraocular pressure
EP2038124B1 (fr) 2006-06-27 2016-03-09 Giesecke & Devrient GmbH Procédé pour appliquer une microstructure, moule d'outil et objet doté d'une microstructure
AU2007324555B2 (en) * 2006-11-21 2013-12-05 Basf Se Apparatus and method for manufacturing a security product
WO2008061930A1 (fr) * 2006-11-21 2008-05-29 Ciba Holding Inc. Appareil et procédé pour fabriquer un produit de sécurité
WO2009062867A1 (fr) * 2007-11-15 2009-05-22 Basf Se Procédé pour produire une lamelle support d'image optiquement variable
EP3242165A1 (fr) 2011-06-21 2017-11-08 Basf Se Impression de réseaux de diffraction sur un substrat polymère
US10625534B2 (en) 2011-06-21 2020-04-21 Basf Se Printing diffraction gratings on paper and board
US10322603B2 (en) 2011-06-21 2019-06-18 Basf Se Printing diffraction gratings on paper and board
US8993219B2 (en) 2011-06-21 2015-03-31 Basf Se Printing diffraction gratings on paper and board
CN102442054A (zh) * 2011-10-17 2012-05-09 谭日和 一种同步印刷压纹机
EP2849809A4 (fr) * 2012-05-18 2016-06-22 Angelini Pharma Inc Appareil de désinfection de dispositifs portatifs
EP2705952A3 (fr) * 2012-09-05 2018-01-03 Heidelberger Druckmaschinen AG Procédé de génération de structures en relief dans des matériaux durcissant sous l'action de rayonnements
US9878485B2 (en) * 2012-09-05 2018-01-30 Heidelberger Druckmaschinen Ag Method and apparatus for producing embossed structures in radiation-curing materials
US20140061976A1 (en) * 2012-09-05 2014-03-06 Heidelberger Druckmaschinen Ag Method and apparatus for producing embossed structures in radiation-curing materials
CN103395282A (zh) * 2013-06-28 2013-11-20 广东新优威印刷装备科技有限公司 一种镭射图案印刷装置
CN103786423A (zh) * 2014-01-27 2014-05-14 虎彩印艺股份有限公司 一种圆压圆透明转印辊
IT201800003900A1 (it) * 2018-03-22 2019-09-22 Raul Maria Orlandi Processo di microincisione di strutture nanometriche su inchiostri e lacche "uv" poste a rivestimento di pellicole plastiche o qualsiasi pellicola o film che possa essere spalmata con tali inchiostri o lacche

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