Plastic containers with a base coat thereon

[0001] The present invention relates to plastic containers having a substrate or primer applied thereon, in particular a digitally printed substrate coating.

[0002] It is highly desirable to provide plastic containers with sharp and legible prints and / or picture markings. Conventional printing techniques on plastic containers, especially on their curved surfaces, have significant drawbacks. For example, it's difficult to get the right caption between colors, and changing images, designs and vocabulary is expensive and time consuming. Inkjet printing with multiple nozzles is very useful for flat surfaces, but it is difficult to use many nozzles with curved surfaces for good results.

[0003] WO 2004/043702 A1 discloses a container described in the preamble of claim 1, and a method and apparatus for producing precise white layers that act as a primer on a substrate for color imaging in an inkjet printing process, by precise inkjet printing on a colorless and poorly bonded substrate frames, thus defining the area to be imaged, and then by inkjet printing or spraying a white layer, which at least partially overlaps the frame and covers the area defined by that frame.

[0004] It would be very desirable to provide a plastic container, especially having a curved surface, with a good print, pictures and / or pictures and markings applied thereto, the final container having optimal quality of the print and pictures. In particular, it would be desirable to print the digitally generated image on a plastic container, especially on a curved plastic container, where such printing could be made at a reasonable speed and moderate cost.

SUMMARY OF THE INVENTION [0005] The above objects are easily achievable in the solution of the invention. [0006] The present invention provides a plastic container, in particular a curved plastic container with a substrate or backing printed on it. The containers with the digitally printed base coat are preferably provided with an outer label printed on the base coat, for example an ink-printed label. The label or print area on the substrate coating may simply be graphics, a product, or a trademark sign, and preferably includes digitally printed ink, or a variety of digitally printed ink colors. The substrate coating enhances the appearance of the outer label favorably by adding layered effects with variable ink thickness that provides a three-dimensional effect.

[0007] Thus, the container according to the invention comprises: a hollow plastic container having a closed bottom support base, a side wall extending upwards from the closed base and a top part with a dispensing opening that extends upwards from the side wall: and a digitally printed coating sidewall, which has a thickness of 1 to 200 microns. At least parts of the substrate coating are digitally raised print areas providing a distinctive three-dimensional appearance, wherein the substrate coating has varying thickness to provide, at least in part, a darker appearance. In a preferred embodiment, the sidewall parts are not coated.

[0008] Further features and advantages of the present expression are set out below.

BRIEF DESCRIPTION OF THE DRAWING [0009] The present invention will be better understood with reference to the illustrative drawing in which:

Figure 1 is a perspective view of a plastic container according to the invention with a digitally printed base coat, and with the printing area thereon;

Figure 2 is a side view of an alternative solution of the plastic container according to the invention with a digitally printed base coat;

Figure 3 is a side view of the container of Figure 2 with a thicker, digitally printed base coat; and

Figure 4 is a side view of the container of Figure 3 with an even thicker digitally printed base coat.

DETAILED DESCRIPTION OF THE PREFERRED SOLUTIONS [0010] As shown in Figure 1, a blow molded plastic container 10 with a substrate coating 12 that has been digitally printed on it is provided. The digital printing procedure preferably includes clamping the empty container and optionally applying internal pressure to the container interior, the range of which begins with a vacuum, for example from -0.07 to 0.35 bar (-1 psi to 5 psi). The clamped and pressurized container is preferably subjected to pretreatment, e.g., heat, or corona discharge to increase surface energy ensuring good ink adhesion to the container. The pre-treated container will have a digitally printed base or backing. It can be a direct drop on demand of the ink head, or an indirect drop on demand of a Pad inkjet printer. If desired, the digitally printed area can be realized by screen printing, or the print can be applied by hand with a down-pulled tool. UV ink can be applied directly to the desired surface of the container in one pass. The container with the printed substrate coating is then cured in a curing station to cure the applied substrate coating.

[0011] As shown in Figure 1, the undercoat 12 is applied to the side wall of the plastic container 10 with base area 16, tapered area 18 and neck, or top area 20 with a dispensing opening 21 that has remained untreated. Substrate coating 12 has been applied circumferentially over the entire sidewall, although it is possible to leave desired sidewall areas without treatment. Additionally, in the solution of Figure 1, the reverse print area 22, identified as the "label", was not coated; while the raised print area 24, identified as the word "sample", has been printed on the substrate coating, and can be seen as having a characteristic three-dimensional appearance. Additional printing may be applied to the remainder of the undercoat to provide the desired color and / or appearance of the label with identification, picture representations, descriptive material and the like. The uncoated reverse print area has a distinctive three-dimensional appearance.

[0012] As mentioned above, the substrate coating may have any desired appearance, both pronounced and opaque color. In the solution of Figure 1, the substrate coating has a light color. The purpose of the undercoat is to enhance the appearance of the label printed or applied to the coating by adding a layered effect with varying ink thickness that provides a three-dimensional effect. The substrate coating may be used in such a way that the substrate color, bottle color and the like show that they are part of the graphic design of the label. This can be done in such a way as to emphasize on the container certain characteristics shaped on it, such as letters in the logo or distinguished features, such as water droplets shown, for example, in Figures 2-4. The substrate coating may have, at least in part, a raised or textured image to enhance the appearance, feel and / or grip. [0013] Thus, Figure 2 shows an alternative solution of a plastic container 30 made by blowing, and having a base 32, a side wall 34, a conical part 36 and a neck, or an upper part 38 provided with a dispensing opening 39, similar to that of Figure 1. The side wall 34 is provided with a digitally printed base coat 40, like the base coat 12 in Figure 1, with the conical part 36, neck or upper part 38, and the base 32 not being coated with the base coat. However, the water-drop configurations 42 formed do not have a substrate coating thereon. Thus, when the label area is printed on the base coat, as in Figure 1, but not on the water drop configurations, the characteristic container sidewall will be impressive with water drops 42 not having a print or coating thereon.

[0014] Container 50 in Figure 3, similar to container 40, has a digitally printed backing 52 and uncoated water drops 54. However, the backing 52 is thicker than the backing 40, the thicker areas having a darker appearance. Also, the container 60 in Figure 4, which is similar to the container 40, has a digitally printed substrate coating 62 and uncoated water drops 54. The undercoat 62 is even thicker than the undercoat 52 and has an even darker appearance. Thus, when the label area is printed on the substrate coatings in Figures 3 and 4, as well as in Figure 1, but not on the water drop configurations, the characteristic sidewall will be as impressive as in Figure 2. According to the invention, thicker portions of the undercoat are only found on the sidewall parts to obtain a light / dark color system, or variation in color appearance. [0015] The container according to the present invention with a digitally printed substrate coating has a number of significant advantages. The base coat, which can be white, opaque, or any desired color, allows better color management in typical inkjet printing processes. The substrate coating provides a repeatable and homogeneous surface to which multi-color graphics can be applied using a conventional inkjet printing process. In addition, the digitally applied substrate coating provides the proper surface energy (dyes per square centimeter) required for optimal image / print quality.

[0016] The substrate coating has a thickness of 1 to 200 micrometers, preferably 3 to 100 micrometers, and optimally 15 to 50 micrometers. The substrate coating preferably has characteristics such as, in general, chemical resistance and resistance to scratches or abrasions, and may be based on solvent, water and radiation-cured. In addition, a wide range of base coat colors, preferably clear or opaque, can be used. A substrate coating can provide a barrier layer to the surface to reduce its permeability. The specific gravity of the base coat should be at least one, preferably from 1.25 to 1.5. Moreover, different application methods can be used, and the characteristic features or designs can be easily printed or applied.

[0017] It should be noted that the invention is not limited to the described and illustrated illustrations, which are merely illustrative of the best aspects of the embodiment of the invention, and which are suitable for modifying the shape, dimensions, assembly of parts and details of operation. All such modifications are included within the scope of the invention as defined by the claims.