Technology Innovation in Plastics Decorating

by Edward B. Crutchley, Crutchley Consulting Limited

The plastics industry is the third largest in the US, and aesthetics play an important part in most plastic products. As part of that, plastics decorating is a wide-ranging and yet fragmented subject. Most people involved with it find themselves specialized in less than a handful of the dozens of often competing process technologies that commonly are used today.

The plastics decorating industry also is fragmented because manufacturing, products and end-uses are so varied, different and separated. Whether working for the automotive, cellphone, packaging, white goods or countless other markets, plastics decorating often is only a very small part of much larger product-specific molding and assembly production lines working completely independently of each other.

There is a need for more cross-fertilization. Plastics Decorating and the SPE Decorating and Assembly Division are almost unique in bringing the industry together. What is needed is even more effort to provide a running global perspective of plastics decorating, especially regarding innovation.

With this in mind, and in the hope of encouraging more such analyses in the future, a three-year review of media articles and patent documents related to innovation has been carried out, focusing especially on different types of decorative or sensory effects produced and how different process compare [1].

A surprising amount of information was uncovered over that period of time. During the three-year period of the study, one to two relevant items of interest were found per day. Patent documents, more than 1,000 in all, accounted for 75 percent of material gathered. “Patents” includes those that were applied for as well as granted.

Although well over 500 companies around the world were identified whose innovation touching decorative effects was published in either articles or patent documents, a significant majority of them were headquartered in Germany, Japan or the US.

With respect to focus, materials development accounted for 45 percent of all types of innovation, and in-mold operations accounted for 40 percent of the activity related to process innovation. Table 1 shows a breakdown of patent activity by process or material category.

With respect to process development, unsurprisingly, the relatively newer processes (in-mold, inkjet, etc.) had more to offer.

Table 2 shows patent ranking according to the aesthetic or sensory effect produced either through materials or process development. Surface quality improvement represented the most activity (and, it was interesting to note, a year-to-year average increase of 30 percent. This was followed by 3D, tactile and depth effects (slight decline) and metallic effects (stable over the three-year period).

A number of patent clusters were noted. These are groups of patent documents from different companies related to the same subject, sometimes even claiming close to the same innovative step. For any innovation considered original, a granted patent is awarded to the first to file (“priority date”), and only about one in four applications reached this status. The following list shows examples of patent clusters in plastic decorating and surface treatment from 2011 to 2013.

1. Color change additives: Laser additives to improve marking speed and quality.
2. Color variation: Techniques to produce color gradients and swirls during molding.
3. Effect materials: New and improved interference pigments.
4. Film insert molding: Techniques to reduce the number of separate operations leading to back-molding a predecorated plastic outer shell.
5. Inkjet printing: Equipment for 3D shapes.
6. In-mold coating: New techniques to avoid a separate spray coating process.
7. In-mold film processes: Use of a temporary film material in the mold cavity to produce relief effects or patterns.
8. In-mold films: Films that produce relief and tactile or visual 3D effects.
9. Multilayer molding: New techniques to produce multiple layers for decorative effects.
10. Organic coatings: Easy-to clean and anti-fingerprint coatings for plastics.
11. Pad printing: Multilayer and hollow pads in order to more flexibly decorate shapes.
12. Plating: Alternatives to sulfochromic chemistry.
13. Plating: New selective deposition techniques, such as laser direct structuring (LDS).
14. Spray coating: Improved electrostatic devices (shape and temperature control, etc.)
15. Surface improvement: Using filled product pressure to improve surface quality in blow molding.
16. Surface improvement: New RHCM (rapid heat cycle molding) techniques.
17. Vacuum deposition: Direct metallizing onto a plastic substrate without basecoat.
18. Vacuum deposition: Ceramic deposition (e.g. gold colors from reactive sputtering from titanium or zirconium targets) in order to avoid organic topcoats.
19. Vacuum metallizing: Rapid-cycle inline devices.
20. Vacuum processes: Ion implantation to improve surface hardness and gloss.

The study’s search found hundreds of materials innovations for obtaining color, color-change, depth, gloss/matte, interferential, metallic, olfactory and taste, reflective, surface improvement and tactile effects in molded and decorated plastics. Even more process-oriented innovations also were uncovered in both traditional and new technologies.

Undoubtedly inkjet represents an important ongoing development in plastics decorating, whether it be in the form of wide format or conveyor devices for near-flat surfaces, peripheral printers or robotic devices. The latter two still are in their relatively early stages, but companies such as Dubuit, Hinterkopf, ITW, Kammann, Polytype and Till (up to 36,000 bottles per hour) are beginning to make their mark. FTP Robotic/Arburg have developed their InkBot process for robotically decorating out of the mold.

Metallic inks are possible with micronized pigments from such companies as Eckart and are subject to several patents [2]. Inkjet has been proposed to produce relief surfaces before vacuum metallizing [3] or as a relief topcoating or painting process [4]. The dual use of inkjet for applying either selective coverage or overall film on polymer surfaces is increasing. As a digital process, not only does inkjet enjoy the possibility of instant changeover, i.e. sequential parts printed from completely different artwork, but also on-the-fly color or contrast correction as needed [5], something barely possible with plate or screen processes.

Laser decoration is another digital process receiving plenty of attention. Many new laser additive materials for improving definition, contrast or sensitivity have been proposed, mostly in patents from BASF, DSM, Eckart and Merck. The use of lasers for inkless color printing features in patents from UK company Datalase [6] and P&G [7].

More traditional decoration processes have received potential boosts. Flexographic printing quality has been improved with high-precision Dynamic Roller Positioning from German company Isimat. Italian company OMSO has introduced indirect flexography for absorbing wall variation in moldings [8]. Polytype has introduced its multiprocess Linearis decorating machine [9]. Pad printing stands to benefit from pads of nonconventional design (hollow, multifaceted, dual durometer, etc.) for improving shape coverage or printing in restricted areas [10]. The potential of increasing screen printing detail has been improved through the use of ultra-fine meshes aided by ultrasonics [11]. Taica has introduced a water transfer process employing UV-coated relief effects [12]. Leonhard Kurz has introduced the 3DHS hot foil stamping process whereby the foil is preshaped to the part, making for a process able to compete with metallizing for certain shapes. Cold foiling, which can be carried out at much higher speeds than hot foil stamping, has been proposed for flexible tubes by Leonhard Kurz and Isimat.

The preponderance of innovation in in-mold techniques includes dozens of in-mold films proposed to create 3D, tactile and depth effects.

Leonhard Kurz has proposed in-mold decoration (IMD) using relief foils [13]. High Voltage Graphics has proposed in-mold flocking from supplied sheet material [14]. An ingenious invention from Veriplast provides for in-mold labels (IML) with tactile effects produced using Mucell technology combined with a reverse printing technique to selectively prevent label adhesion where relief is required [15]. Several film insert molding (FIM) techniques to reduce the number of manufacturing steps have been proposed, e.g. IMD-Pro [16]. Several companies have proposed in-mold creation of relief surfaces by placing a temporary relief film in the mold prior to injection, for example, to save on tooling and changeover costs [17]. Holographic images produced from etched molds have been proposed by Nano 4U. An article in Kunststoffe International magazine in March 2013 talked of pad printing onto the surface of the mold before injection, and at least one patent also refers to this possibility [18]. Topline and Viva Healthcare have boasted in-mold labeling of flexible tubes. The use of self-stratification during injection molding has been proposed to produce a metallic surface [19] or an external hard scratch-resistant layer [20]. In-mold techniques proposed for the all-important molded surface quality improvement include new RHCM techniques [21], forced venting (Swiss company Fondarex), vent cycle [22], ultrasonics for improved cavity filling [23], exploiting fluid pressure when blowing and product filling containers at the same time [24].

3D, tactile and depth effects have been proposed in coated films containing platelet pigments by using embossing rather than magnetic techniques [25] or by cold foiling using thick adhesive deposits to create relief effects [26]. In a number of variants, infrared absorbing inks have been used in order to be able to selectively deform polymer surfaces for 3D and tactile effects, shaping, etc. [27].

In other materials developments, low-temperature powder coatings for polymers have been proposed [28]. Eight-layer interference pigments provide brighter color effects [29]. CrVI-free electroplating solutions have been claimed in 16 observed patent applications over three years.

More than 80 mostly UV-cured, often anti-fingerprint/easy-to-clean, scratch-resistant coatings have been developed for polymer surfaces in the past three years, as well as self-healing coatings [30]. Printed electronics from such companies as Bemis, Novalia Pragmatic Printing, Thin Film Electronics, Think4D and Wipak will enable the possibility for talking or music-playing effects in labels. Smart labels also exploit either color-change materials (e.g. for detecting food degradation, humidity or temperature changes) or films that change reflectivity or adopt metallic effects in humid conditions. French company Solev has even proposed that a label’s decoration be remotely electronically controlled via Wi-Fi [31].

In coating solutions, polymer coating developments have included the use of thermal spraying for powder coatings. Electrostatic spraying devices for liquid coatings have been developed with improved temperature control [32], voltage control [33] and spray fan control [34], as well as alternative methods for rendering plastics suitable for electrostatic spraying [35]. Pinning of coatings using a UV pre-cure has been used in order to prevent or reduce pinholing in liquid coatings [36], and dry ice cleaning of substrates prior to spray coating continues to receive attention [37].

In the field of vacuum deposition, several companies have proposed ceramic coating onto polymers (e.g. for gold colors, avoiding the need for an organic protective topcoat) [38]. Vacuum deposition of organic materials, e.g. for metallizing basecoats and topcoats, has been proposed [39]. Selective vacuum deposition has been proposed by preprinting a thin film of oil in unwanted areas [40]. Ion implantation has been used in order to modify or improve gloss and hardness of moldings [41].

Inline rapid-cycle metallizing solutions (six- to 12-second cycles) for metallizing up to several thousand small parts per hour have been developed by Marca Coating Technologies [42], Italian company Tapematic [43] and shortly by VTD from Dresden, Germany.

Atmospheric plasma deposition of metallic films is available from Plasmatreat [44]. In electroplating, selective electroplating using laser direct structuring of the substrate prior to plating has been proposed by several companies [45].

In conclusion, innovation in plastics decorating is thriving across the board, even for processes that have been established for decades. Tracking innovation has become an important route to staying ahead of the game and spotting new opportunities. For this, more tracking is needed in the future.

Edward B. Crutchley is a specialist in plastics decoration and surface treatment. He provides a monthly innovation watch and annual survey for major players in the plastics industry.

References:

(Patent documents can be downloaded from http://worldwide.espacenet.com, which also has translating facilities.)

1. Innovation Trends in Plastics Decoration and Surface Treatment. Smithers Rapra Technology, 2014. ISBN: 978-1-909030-84-8.
2. US7891799 (Electronics for Imaging); US20120274714A2 (Eckart). Also, several others who claim bright metallic effects in paints and coatings using micronized flake pigments.
3. EP2047315 (Tapematic).
4. US20110177303A1; WO2011064075A1 (Theodor Hymmen Holdings); WO2011138441A1 (Sueddekor); WO2013182280A2 (Eisenmann); several others.
5. WO2011121810A1 (Dainippon Screen); DE11013683B4 (Atlantic Zeiser).
6. WO2011089447A1 and others (Datalase).
7. US7897320B2 (Procter and Gamble).
8. EP2263875A1 (OMSO).
9. US20110067584A1 (Polytype)
10. US7870823; WO2011108034A1 (Shuhou); US20120222574A1 (Bridgestone Sports); US20130298788A1 (SGD).
11. WO2011110795A3 (DTG International); US20130098254A1 (Ashmore).
12. Taica E-Cubic process.
13. WO2011000485A1 (Kurz).
14. US835450 (High Voltage Graphics).
15. US20110039046A1 (Veriplast Decorative).
16. IMD-Pro process from Skoda and HBW-Gubesch Kunstsoff Engineering.
17. US20110151208A1; WO2011081994A1 (3M); WO2011115383A2 (SNU R&DB Foundation); WO2012112470A1 (Nypro); others.
18. US7870823.
19. US8197730 (Cool Options).
20. US20130302615A1 (LG Chem).
21. WO2011114378A1 (Mitsubishi Heavy Industries Plastic Technology); US8092208 (Chung Yuan University); US8105529 (Bi Group Services); others.
22. WO2013016816A1 (Husky).
23. WO2013013645A1 (Lu-Ming); US20130345384A1.
24. WO2012044362A1 (Ticona); WO2013020885A1 and others (Nestec); WO2012166541A3 (Amcor); US20130106027A1 (Maki); US20130113143A1 and others (Sidel Participations); others.
25. WO2011116036A2 (Gillette Co.); WO201207967A1 (Merck); WO2012007563A3 (Sun Chemical).
26. WO2011110956A3 (Scodix).
27. US20130075959A1 (DIC Corp.); US20130193027A1 (Altira).
28. US20110028638A1; WO2012034901A1 (Arkema Coatings Resins).
29. US20130216597A1 (Merck).
30. WO2012111947A2 (LG Chem).
31. US20130122817A1 (Solev).
32. US20110159196A1.
33. CN101970125A.
34. US20110014387A1.
35. For example, Lucon PS-6080EX from LG Chem.
36. EP2419223A1 (3M); WO2013146730A1 (Fujifilm Corp.).
37. DE1020090582B4 (Venjakob Maschinenbrau); WO2013149713A1 (Rehau).
38. ES2365995T8 (Vapor Technologies); CN201328477A (Xiamen Runner); others.
39. US20110111131A1 (Fraunhofer); EP2202059A4 (Ulvac).
40. US20110297087A1 (Gallileo Vacuum Systems).
41. US20110070411A1 (Hyundai); WO2012038369A1 (Valeo Vision).
42. US20130037407A1 (Marca).
43. US20120234670A1 (Tapematic).
44. Plasmatreat Fine Powder Coating (FPC) process.
45. CN102071412A and others (Byd); US201103644A1 (Arlington Plating Co.); US20120100305A1 (Eta Sa Manufacture Horlogerie Suisse); US20130048519A1 (FIH); others.