This section covers all types of film materials, whether for in-mould or off-line applications, as integral films (including labels) or transfer films (in-mould, hot foil or heat transfer and so on). The primary purpose of any patent here may be a distinctive decorative or sensual effect, or it may be aimed towards ease of manufacturing. In the latter case the category ‘surface quality improvement’ refers to where the principle focus of the patent is to improve performance during and after processing to make the final object, i.e., optimising the balance between ease of processing, deeper drawing (in the case of in-mould films), and the abrasion, chemical and visual performance of the result. Followed by three-dimensional (3D), tactile and depth effects.
These films are almost always multilayer by virtue of the co-extrusion, lamination, decoration or coating processes employed in their manufacture. Depending on the application, films typically have a base resin layer (or carrier); a release layer if any separation is to occur; a separate adhesion layer for adhering to a polymer substrate if transfer is involved; a decoration layer which may be vacuum metallised and/or printed in sheet or web form (typically using digital printing, flexography, gravure, offset, or screen or combinations of either); topcoating, often with an ultraviolet (UV) cured organic coating to protect and provide scratch resistance and final surface finish. Some films also have an additional temporary protective layer, which is removed after any thermoforming or in-mould operation, either to protect gloss and avoid scratching during the forming process, or to preserve a relief pattern. The demand for abrasion-resistant topcoats implies the need for a hard (and therefore brittle) surface, adding to the challenge when the film has to be deformed. For this reason a commonly used technique in in-mould applications requiring significant degrees of deformation is to use films with dual-cure protective coatings and carry out a final UV hardening cure after forming. If the film is used for a transfer process, clean release properties and subsequent good adhesion of the transferred portion are required. If the film is to be adhered to the substrate polymer, choice of suitably compatible material for adhesion is important. Most such films for film insert moulding are manufactured in polycarbonate (PC)/polybutylene terephthalate-blend films, polymethyl methacrylate or polyethylene terephthalate (PET). A compatibility chart with moulded materials can be found in reference.
The products for which these films are destined are, of course, restricted by their shape. The technical challenge in each case is to provide a wrinkle-free finish without visible cracking, whitening, or delamination occurring during processing. While stretching of 200% or more may be possible with high pressure thermoforming processes, this may be significantly restricted when decoration or metallisation is present.
Whilst in decorative processes on plastics the trend is towards process integration in favour of value adding for the moulder and better process control, there is the supply chain issue in the case of films. The ability of tailor-made film production to face the challenge of fast turnover and shorter run length is put to the test. The processes in which these films are employed and the challenges they are subjected to are described in later sections. Films can often be considered to be finished products in themselves and their variety of combinations of relief, haptic and visual effects render each solution unique.
Not captured in the patent literature, since it falls outside the scope of this website, but an important emerging feature mentioned in commercial developments, is the arrival of printed electronics that allow additional features for labels such as making sounds or varying visual effects.
The vast majority of patent documents here can be located by using any of the International Patent Classification search codes B29C (Shaping or joining of plastics; shaping of substances in a plastic state, in general; after treatment of the shaped products, e.g., repairing), B32B (Layered products, i.e., products built-up of strata of flat or non-flat, e.g., cellular or honeycomb form), B44C (Producing decorative effects) or B41M (Printing, duplicating, marking, or copying processes; colour printing).
2. Recent Commercial Developments
2.1 In-mould Films
Picasus® film from TORAY INDUSTRIES is a conductive metallic lustre film with lamellar layers made without metal, designed for replacing plating and PVD and suitable for in-mould decoration (IMD); PROELL INC., developed its Noriphan® XWR 2K ink that resists film deformation during in-mould applications; INKWORKS PRINTING talked of the use of high-speed digital printing (LANDA’s Nanography™) for IMD films; MARABU announced its new Ultramould UVPC screen inks for IMD; MACDERMID AUTOFLEX has added Autoflex® EB embossable UV-coated hard coated film for in-mould applications; MACDERMID AUTOTYPE has demonstrated its new Autoflex® XtraForm; CYTEC announced its flexible urethane acrylate Ebecryl® 4858 coating for protecting in-mould films; AKZO-NOBEL SOLIANT publicised its Fluorex® metallised film for in-mould applications; TORAY INDUSTRIES developed a multilayer metallised PET film called Lumirror® FA6 ; MACDERMID AUTOTYPE has developed Autotex® Steel hard-coated PET film which has a brushed stainless steel appearance and hides fingerprints; EFI has developed thermoformable inks suitable for deep draw for their VUTEk GS3250 Pro-TF and GS2000 Pro-TF printers UV light-emitting diode (LED) curing inkjet printers; Norilux® DC – abrasion resistant dual-cure screen printing lacquer from PROELL INC., is designed for PC and poly(m-methylstyrene) films for in-mould applications. Final curing after thermoforming is by UV. MACDERMID AUTOTYPE has developed Autotex® Softouch polyester film for in-mould applications. TEIJIN has developed a PC resin blend for thinner-wall IMD with improved surface quality.
2.2 Labels and Sleeves
SUN CHEMICAL and POPIMS have co-developed an alternative to lenticular printing for labels using single-pass flexographic printing; LIBO COSMETICS CO. LTD., has used embroidered fabric to decorate cosmetics compacts; AVERY DENNISON introduced its Prime Film Portfolio, Shrink PS, TurnLock™ Laminating System, Wash-Off, MultiCycle™, Z338 Adhesive, and Bottle-to-Bottle portfolios; SLEEVER has developed more than 26 tactile effects for their films; AVERY DENNISON has launched a new website that provides advice and experience for label design; DOW has developed the VISIQUE™ stretch sleeve label for highly contoured bottles; SLEEVER offer a new range of sleeve effects for lipstick packaging; AVERY DENNISON has developed for labels a PET iridescent film called Fasson® Diamond; SYSTEMS LABELLING LTD., exposed its R-IML® in-mould label that can be removed for recycling; SEALED AIR’s new Cryovac® LT-1 shrink sleeve label has a density lower than the 1 g/cm3 PET recycling standard; VERSTRAETE has developed transparent barrier labels for in-mould labelling; an in-mould label that is printed on both sides in order to provide more information; and peelable in-mould labels designed for containing more information. AVERY DENNISON announced its Curve Appeal™ label range for wrapping around complex shapes; BRICKSTIX have applied for a patent for reusable decals for plastic toys; and ACCUDIAL PHARMACEUTICAL have applied for a patent for a multiple-layer label system in which the top label can be moved over the base label and may have a window.
2.3 Smart Labels.
Printed electronics solutions for labels are available from NOVALIA; integrated printed electronic functionality on INNOVIA FILMS (BOPP) label substrate has been made available by PRAGMATIC PRINTING; WIPAK has developed and won an award for talking packaging; APPLE INC., has filed for a patent for active packaging; THINK4D® has developed electronic solutions for packaging; NOVALIA has created a poster that plays music clips printed with conductive inks; PRINTECHNOLOGICS GmbH has received an award for their Touchcode, an invisible electronic data tag that prompts a mobile device to display information; BEMIS and THIN FILM ELECTRONICS ASA have joined forces to use printed electronics technology to manufacture and launch intelligent labels; SAY IT CORP., has developed an electronic device that is activated when a can is opened. FRESHPOINT HOLDINGS SA have applied for a patent for a time-temperature indicator for a label capable of providing a summary of the time and temperature history.
2.4 Transfer Foils
New holographic and depth effect foils from LEONHARD KURZ STIFTUNG & CO. KG include SB Aquadrops and Diffractive Lens; and LEONHARD KURZ STIFTUNG & CO. KG has developed 3D tactile films for hot stamping and IMD.