Latest production line for silicone coating for release liners on show at Bobst Italia’s open house

There was a great deal of interest and excitement in the run up to the silicone coating technology event held at Bobst Italia in S. Giorgio Monferrato, Italy in July. The occasion marked the unveiling of BOBST’s new silicone coating line for paper and flexible substrates for the production of release liners. Furthermore, it marked the impressive outcome of major investments by BOBST in the past few years to infuse new strength and resources dedicated to the development, engineering, sales and project management of specialty coating equipment.

The specialty coating market is large, albeit segmented and diversified, encompassing a wide variety of different applications; the main technologies that BOBST is focusing on relate to the industry segments of label stock and release liners, adhesive tapes and pre/post metallising, so as to further expand the offering of high performance packaging and converting solutions. This also reflects the main fields of experience developed by Rotomec in specialty coating since 1960.

Bobst Italia’s open house focused on the ROTOSIL, BOBST’s latest production line for silicone coating technology and the machine on display provided the opportunity to give the participants an overall view of the latest developments of technology and market trends in this field.

The visit to the machine was preceded by presentations given by guest speakers: French converting company Gascogne Laminates, owner of the ROTOSIL line on display, presented their company and solutions and gave an interesting perspective from the point of view of a specialty converter. Dow Corning gave an overview of the silicone-related coating market in terms of applications, technologies, latest market trends and drivers of growth.

Bobst Italia presented its latest portfolio in special coating technologies and more specifically illustrated the most innovative and performance features of the ROTOSIL production line on display. ROTOSIL addresses the needs of the high end of the silicone coating market.

Versatility is one of the most appealing features of the line alongside the quality of performance, the ergonomics, the reliability and the eco-efficiency of the solutions devised.

The coating unit is trolley type which provides for optimum flexibility and versatility of the line through the possibility of applying different coating methods. This also allows for encompassing changes in the configuration to match future market trends and new requirements.

The coating unit can be configured as a five-roller unit for solventless silicone coating or as a rotogravure coating unit for applying water- and solvent-based silicone. This means that with two different trolleys it is possible to use as many as five different types of coating applications.

The design of the five rollers coating units enables achievement of the optimal accuracy and repeatability on the final products also at low coating weight.

Versatility also means that the ROTOSIL line is pre-arranged for trouble-free inclusion of additional equipment to match specific production requirements including in line gravure printing or slitting units.

The coating unit is fully enclosed with dedicated air suction and exhaust systems in order to minimise emissions, and the main controls are located outside the enclosure for operator’s safety.

The ROTOSIL platform has been specified for speeds up to 1000 m/min and the modules comprising the line have been designed for solid construction, reliability and repeatability during operation at high speed in all the different specifications that might be requested.

The drying and curing section of the machine is very impressive. All the component sections have been designed in house and benefit from Bobst Italia’s longstanding know-how and experience in providing the same curing level across the web width as well as offering other distinctive advantages in terms of equipment functionality and efficiency. Each tunnel section features an independent top and bottom air supply with independent  control of the air pressure so that different set ups are possible to match the different product requirements. The individual variable recycle system for each tunnel section provides for optimised energy consumption.

The principles of ergonomics and safety that are applied at their most extensive level throughout the line are clearly illustrated by the wide accessibility for web threading and maintenance and the opening/closing system in electronic shaft control without mechanical transmission. All safety solutions have been validated by a certified risk control company.

When handling paper substrates, re-moisturisation is a critical factor because it is instrumental in preventing defects and breakage of the web. The ROTOSIL system consists of one or more steam humidifiers. BOBST’s in-house design provides for individually adjustable sections so that each zone can have the most fitting steam flow rate in order to achieve a uniform moisture level across the web, whilst reducing the amount of steam required, thus enabling achievement of some additional savings through lower levels of energy consumption. The ROTOSIL is equipped with automatic shaftless winders.

The event was attended by major converting companies operating in the specialised industry segments of silicone coating for release liners and self-adhesive tapes.