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Xmelt DF hotmelt hoses are designed to minimise the negative impacts of adhesive degradation, including issues such as charring, premature curing, discoloration, and unpleasant odours. They ensure trouble free production and higher system availability
Hot melt systems, despite the continuous flow of hot melts, are prone to charring. This happens when even the smallest remnants of hot melt accumulate in tiny spaces and burn, forming hard, dark lumps that clog filters and nozzles. Over time and unavoidable, hot melt residue builds up on the inner walls of the existing hotmelt hoses, causing further charring. This build up can cause blockages, leading to packaging process failures and disruptions to upstream processes. Consequently, the components of the hot melt system may need to be flushed and prematurely replaced due to charring. Taking proactive measures is essential to prevent disruptions and reduce waste for sustainable and profitable production.
Hot melt adhesives rely on the presence of oxygen to undergo a charring process when utilised with hotmelt equipment at typical operating temperatures. The synergy between heat and oxygen accelerates the formation of char, potentially leading to complications in adhesive applications. To mitigate charring, two approaches can be employed: reducing the adhesive temperature and minimising or eliminating exposure to oxygen.
The engineers at Baumer hhs have discovered the causes of charring in hotmelt hoses. They conducted an experiment where they heated multiple hot melt hoses with different designs to simulate burns. When the adhesive was released from the hoses, it became clear that the adhesive in the metal connections did not show any signs of burning, while clear signs of burning were observed in the flexible hose, indicated by different discolorations. The lack of charring in the connection area can be attributed to the metal being gas tight, as the temperature of the connections is equal or higher. Conversely, charring occurred in the plastic hose area, indicating that these are not gas tight.
The findings from the research show that as temperatures increase, the ability of oxygen to pass through thermoplastic tubing grows significantly. Even materials like silicone or PTFE, which are relatively resistant to permeation at room temperature, become noticeably more permeable at higher temperatures. This finding is significant because it demonstrates that when a small amount of hot melt contacts the expansive inner area of the thermoplastic tubing, it enhances the transmission of oxygen due to the increased surface area. the transmission of oxygen.
After realising how important it is to minimise exposure to oxygen, the company worked closely with development partners to tackle this challenge. The investigation led to the gas industry, where it was found that gas hoses, which need to be both airtight and flexible, could be a suitable solution. After thoroughly researching patents and literature, it was discovered that using a hot melt hose with a flexible metal core for transportation was not a new idea, but it seemed to be the most effective option available at the time.
The positive impact of Xmelt DF hoses was assessed by comparing a standard hose with a PTFE inner core to an Xmelt DF hose. Both hoses were continuously heated for 50 hours at a temperature of 180°C. The results were noteworthy: the adhesive from the Xmelt DF hose remained absolutely clear and unchanged, while the adhesive from the standard hose showed strong signs of burning and discoloration. This resulted in nozzle and filter blockages during production.
The abbreviation DF stands for ‘degradation free’, a claim supported by extensive testing. Xmelt DF hoses effectively avoids burning, ensuring trouble free production and higher system availability.
The Xmelt DF hoses offer several additional benefits worth considering. Components such as nozzles, filters, and hot melt hoses often require frequent replacement due to blockages and deposits. However, these issues can be minimised by utilising Xmelt DF hoses. Furthermore, the Xmelt DF hose is now equipped with a durable, enclosed covering that is highly resistant to abrasion and completely waterproof on its outer surface. It is expected that the Xmelt DF hoses will have double the lifespan of traditional hoses. Surprisingly, it was found that the energy consumption of Xmelt DF hoses is approximately 20% lower due to the superior heat transfer of the metal inner tubes compared to PTFE or silicone inner tubes.
Baumer hhs encountered a significant obstacle when a competitor filed a patent for a flexible hot melt hose featuring a metal inner core. This hindered the company's development efforts for several years. In response, Baumer hhs, along with two other industry partners, took proactive measures to oppose the patent claimed by the competitor. Their efforts culminated in the complete revocation of the patent by the European Opposition Division on May 8, 2024. This outcome ensures fair competition and secures access to gas tight hot melt hoses for all industry players.
The Xmelt DF hoses are now available for Baumer hhs systems and competitor systems equipped with Ni-120 RTD. There is also a limited time introductory discount of 50% until July 15, 2024.
Visit hall 6, stand a30 at drupa 2024 to learn more.
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