Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/02—Printing inks
  • C09D11/10—Printing inks based on artificial resins
  • C09D11/106—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/14688—Coating articles provided with a decoration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F15/00—Screen printers
  • B41F15/08—Machines
  • B41F15/12—Machines with auxiliary equipment, e.g. for drying printed articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M1/00—Inking and printing with a printer's forme
  • B41M1/12—Stencil printing; Silk-screen printing
• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/14688—Coating articles provided with a decoration
  • B29C2045/14704—Coating articles provided with a decoration ink decorations
• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/1418—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the inserts being deformed or preformed, e.g. by the injection pressure

Definitions

• the present invention relates to a method of printing a support, by screen printing.
• inks used for all types of printing processes contain a pigment, a binder and a solvent.
• the pigment gives the color
• the binder is used to fix the color, according to the given pattern, on the support and the solvent is used to obtain the desired fluidity of the ink, before its use.
• the solvent, during the printing process, is then removed, most often by evaporation.
• the fluidity or viscosity of the inks to be used differs and for this purpose, the inks contain other additives intended, for example to increase or decrease this viscosity or to obtain other physical properties necessary for the 'final application.
• screen printing the ink is applied to the support through a screen and in mesh through which the ink can pass and mesh closed, so that the ink is applied in a given pattern.
• different layers of ink are applied successively with different screens, according to the elementary patterns corresponding to each color.
• it is necessary that each layer of ink is stable once dry, that is to say that there is no risk of transfer or smearing, during the application of the layer. next ink.
• the ink currently used in screen printing comprises, to obtain this stability, a binder comprising at least two components which react chemically together to form a stable film fixing the pigment on the support or on the previous printed layer.
• Such an ink is described, for example, in international application WO83 / 01019.
• This document describes a screen printing process in which an ink is used, the binder of which contains a polyamide adhesive resin and a component forming a nitrocellulose film which react together to form and fix the ink, depending on the pattern. desired impression, on the support.
• US Pat. No. 4,351,871 also describes a screen printing process in which an ink is used, the binder of which contains two main components, namely a material which can form a polymeric, thermoplastic film which can be crosslinked and a crosslinking agent capable of crosslinking this material, and moreover, a catalyst releasing the crosslinking reaction.
• the inks currently used in screen printing have the advantage of being stable once dry and give a good quality rendering.
• this printing technique is long due to the long drying time of these inks since drying requires not only the evaporation of the solvent but also that the reaction between the two components of the binder takes place.
• the first layer must be dried for approximately 30 min at a temperature of the order of 60 ° C. before the second layer can be applied.
• the tools used for screen printing are relatively simple and inexpensive. However, the production rates being low, screen printing is a printing technique which is rather suitable for printing small series at the top of the range.
• Inks used for gravure printing use inks with a single-component binder which dry and fix the pigment by simple evaporation of their solvent, and therefore much faster than inks with two-component binders used in screen printing, which require that the reaction between the two components of the binder occurs.
• the binder of these inks being a single-component binder, no chemical reaction occurs and should not occur, which makes it possible to increase the production rates.
• One-component binder inks are therefore used in gravure printing for their fluidity and their ability to dry quickly.
• the equipment used for this printing technique which includes printing cylinders engraved according to the pattern to be printed, is significantly more expensive than that used for screen printing. Since it is only possible to modify the printing patterns at the cost of engraving new cylinders, such modification is costly.
• rotogravure is a particularly fast printing process which proves to be economical for mass production.
• the invention aims to provide a printing process which is compatible with printing in large series at high production rates while allowing modification of the printing patterns which is relatively easy and whose cost is reasonable.
• the invention aims to propose a screen printing process which, while retaining the advantages of this relative technique, in particular the relatively low cost of the tooling, is compatible with mass production.
• the ink comprising such a binder is suitable for the screen printing process.
• This ink dries sufficiently to receive a second layer of ink or a layer of a finishing varnish by simple evaporation of its solvent.
• the drying time is of the order of only 2 min, or even less at a temperature in the region of 60 ° C., so that the drying of a first layer of ink can be carried out without recovery, in an installation in which the support is driven in a screen printing station and then in a drying station.
• two successive layers of ink can be applied in two successive stations of the same printing installation in which the support is driven, stations between which is a drying station.
• a single-component binder is a binder which does not harden or chemically react with another component present in the ink formulation to crosslink or polymerize or produce another chemical reaction, during the printing process. himself.
• the one-component binder of the invention does not undergo any chemical transformation other than drying or hardening due to simple evaporation of the solvent, during the printing process. That such a single-component binder then undergoes a chemical transformation over time, which would simply be due to the normal aging of such a binder, such as oxidation by ambient air, does not however make it a binder with at least two components.
• a preferred ink of the invention is an ink comprising a monocomponent binder based on O. polyvinyl.
• a very particularly preferred ink of the invention is an ink comprising a single-component binder which is polyvinyl butyral.
• ink comprising, in addition, a solvent belonging to the family of glycol and glycol ethers.
• the ink comprising a single-component binder suitable for rotography has a viscosity of the order of 40 cP (4.10-2 Pa.s) so as to be sufficiently fluid to penetrate into the engravings of the printing cylinder.
• the viscosity of known screen printing inks, comprising a binder of the two-component polyurethane type is for example of the order of 500 to 1000 cP (0.5 to 1 Pa.s).
• the viscosity must be sufficient to prevent the ink, after passing through the open meshes of the screen printing screen, from diffusing into areas of the support which must not be printed.
• solvents belonging to the family of glycols and glycol ethers consist of molecules having large dimensions and it has been found that, associated with a monocomponent binder based on polyvinyl such as polyvinylbutyral, they make it possible to confer on the ink the desired viscosity for screen printing and they don't evaporate too quickly, so this ink doesn't dry too quickly.
• Those skilled in the art will be able to choose the proportions of binder and of solvent to obtain a viscosity suitable for screen printing, for example understood, depending on the application which interests him, between 500 and 1,000 cP.
• the solvent is chosen from propyleneglycol methylether, propyleneglycol diacetate, dipropyleneglycol methylether and tripropylene glycol n-butyl ether.
• the solvent can consist of a mixture of these different compounds.
• the invention also relates to an installation for printing a support by screen printing.
• a support by screen printing.
• heliography methods affixing on the support several inks to produce patterns of different colors, the support is driven in a printing line and passes successively under the successive printing cylinders, between which are arranged means of drying. The drying times being short, the printing is thus carried out continuously.
• screen printing methods the supports printed by a first layer must be taken out of the printing line and placed in a drying enclosure for a sufficient time. It is only after the dried media can be reintroduced into a printing line for the application of the second layer. The above operations are repeated for each new printing layer.
• the invention aims to propose a screen printing installation allowing faster printing.
• the installation according to the invention comprises means for driving the support and to the fact that it comprises, successively arranged in the direction of advancement of the support, a first screen printing station having means for applying by screen printing on the support a first layer of ink comprising a single-component binder based on polyvinyl and a first drying station capable of subjecting said first layer of ink to drying.
• the drying station is arranged simply downstream of the first screen printing station in the direction of advancement of the support in the installation. No manipulation of the support is necessary after the printing of the first layer to carry out the drying.
• the installation further comprises, successively arranged in the direction of advance of the support, at least a second screen printing station having means for applying by screen printing to the support a second layer of ink comprising a monocomponent binder based on polyvinyl and a second drying station capable of subjecting said second ink layer to drying.
• successive screen printing stations are arranged downstream from each other in the direction of advancement of the support in the installation, and the drying stations are interposed between said screen printing stations.
• the introduction of a medium leaving a screen printing station in an adjacent drying station is therefore automatic, as is the automatic introduction of a medium leaving a drying station in the screen printing station located downstream.
• FIG. 1 shows two successive printing phases of the process of the invention, implementing the installation of the invention
• - Figure 3 shows a step opening reception.
• supports 10 constituted for example by sheets cut from a film reel 12
• the supports are driven in the stations of the installation by drive means which are only partially and schematically shown and which comprise, for example, advancement rollers 14.
• the installation comprises a first screen printing station 16 and a first station drying 18 arranged one after the other in the direction F of advancement of the supports.
• the first screen-printing station 16 comprises screen-printing means which comprise a table 20 capable of supporting the support 10 during its printing, a screen-printed screen 22 perforated in correspondence with the pattern to be printed on the support 10 and arranged above the latter, and means for applying ink on this screen so that, crossing the openings of the screen printing screen, the ink prints on the support the desired pattern.
• the means for applying the ink comprise, for example, an injection nozzle system 24 and a doctor blade 26 capable, after the injection of ink, of being moved (D) against the screen so as to both penetrate the ink in the openings of the latter and remove the excess ink, an ink bead 28 being moreover represented at the front of the doctor blade in its direction of movement D.
• the screen may be slightly spaced of the support and only be brought into contact with the latter by the action of the doctor blade 27.
• the ink is applied to the support while the latter is stopped in the screen printing station.
• the drive means advance the support step by step in the different stations of the installation operating, each, at the standstill.
• the supports can be cut from the coil 12 when they enter the installation (discontinuous process) or, preferably, when they exit (continuous process).
• the invention implements a rotary screen printing technique which allows printing to be carried out continuously, without stopping the support.
• the screen is shaped as a cylinder stretched at its axial ends on circular frames.
• the ink is applied to the internal periphery of the screen which is itself applied to the supports while moving at a tangential speed equal to the speed of advancement of the latter.
• the ink applied in the screen printing station comprises a single-component binder based on polyvinyl and has a viscosity suitable for screen printing. Because the binder is one-component, and with the appropriate choice of solvent, the ink can be dried quickly in the drying station which is arranged downstream of the screen printing station.
• the drying station 18 is for example in the form of a heating tunnel in which a temperature prevails of the order of 60 ° C.
• the drying time is a function of the length L of the drying station and the parking time of the support at each step. This time is calculated as that which is necessary for the application of the first layer of ink.
• the drying station 18 has a length L which is between 2 and 6 times the advancement step, preferably equal to 4 times the advancement step.
• the length of the station 16 is equal to the advancement step.
• the length of the tunnel is calculated, based on the speed of continuous advancement of the supports, so that the drying time is sufficient.
• the drying is for example carried out by infrared rays or by forced air.
• the printing installation further comprises at least a second screen printing station 26 and a second drying station 28 respectively analogous to stations 16 and 18.
• the supports 10 are driven step by step in the stations 26 and 28 by step-by-step drive means 24, to the application by screen printing of a second layer of ink and the drying of this ink.
• stations 16 and 18 belong to a first printing line at the exit of which the supports are arranged in stack on support means 19. us are then conveyed to the entry of a second printing line which includes stations 26 and 28.
• the support means 19 are shown in phantom. Indeed, they may not be present if, as is advantageously the case, the stations 26 and 28 are directly arranged downstream of the station 18 in the direction of advancement F of the supports in the installation. In this case, the application and drying of successive inks are carried out without recovery, in the same printing line in which the supports are advanced step by step.
• An installation using rotary screen printing and in which the printing stations are arranged one after the other, with drying stations interposed between them has the advantage of avoiding any stopping of the support and any resumption during the whole of the printing process.
• one or more layers of ink are applied, for example 4 to 5 layers each arranged in an elementary pattern corresponding to their color.
• the supports 10 are coated with a protective means. ink.
• ink It is for example a varnish, in which case the supports are arranged on support means 29 which transfer them to a varnishing unit.
• a layer of varnish is affixed to each support using varnishing means 30.
• the varnish applied is advantageously constituted by a polyurethane varnish having a binder of two components. Such a varnish in fact constitutes effective protection of the support against alteration of the printing pattern and surface wear, for example by scratching.
• the drying time of such a complex varnish is long and, after the application of the varnish, the supports are placed on racks in a drying oven 32, to be dried for example for 1 h 30 at a temperature of around 60 ° C.
• the protection means can, as a variant, consist of an attached sheet (laminated) on the printed face of each support (continuously, before cutting the supports relative to the reel 12, or one by one).
• This transparent sheet is for example based on polymethyl methacrylate (PMMA) or difluorinated polyvinyl. It can be complexed on the support by bonding, either using an added adhesive or, advantageously, by the ink itself, when the latter comprises a heat-bonding agent.
• the duration of the drying of the ink having a polyvinyl-based single-component binder according to the invention is preferably at most close to 2 min, at a temperature close to 60 ° C.
• the or each drying station extends over a length L corresponding to 4 steps of advancement and the duration of parking at each step is 10 s, from so that the drying time is 40 s.
• the method according to the invention is suitable for printing on supports made of plastic films intended for decorating a plastic object, for example polypropylene or PNC. It is for example an injection molded object, partially coated by the printed support. It is in particular an outdoor furniture table, the top of which is covered by the support.
• the support is advantageously constituted by a composite film based on polypropylene or PNC capable of being secured to the object to be decorated or by a film intended to be secured with a substrate based on polypropylene or PVC, itself suitable to be attached to the object to be decorated.
• This film or this substrate is advantageously secured to the plastic object by overmolding.
• a decor film is printed using the printing process of the invention described above, this printed film is placed in the cavity of a mold and injects the plastic into this mold by overmolding this film.
• the support film or the substrate is arranged so as to be in contact with the injected plastic, while the ink and the varnish or the protective sheet are opposite.
• the composite film can be thermoformed before its application to the object to be decorated (for example before it is placed in the mold for overmolding) in order to be adapted to the shape of this object.
• the film can be shaped so as not only to cover the horizontal face of the table top, but also the edges of this table.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Printing Methods (AREA)

Applications Claiming Priority (3)

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Family Cites Families (11)

• 2000
  • 2000-11-16 FR FR0014792A patent/FR2816545B1/fr not_active Expired - Lifetime
• 2001
  • 2001-11-16 AU AU2002218384A patent/AU2002218384A1/en not_active Abandoned
  • 2001-11-16 WO PCT/FR2001/003597 patent/WO2002040287A1/fr not_active Application Discontinuation
  • 2001-11-16 EP EP01996465A patent/EP1345779A1/de not_active Withdrawn

Non-Patent Citations (1)

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