CAPS AND CLOSURES | MATERIALS


cled PP is typically white, pearl or grey, with a smell and an opaque or hazy appearance – as well as batch-to-batch fluctuations. Ineos has managed to overcome these concerns


with its Recyl-In rPP2030C – which, he said, is RecyClass certified, collected separately to PCR and compliant with ISO 14021. It is also a mixture of 70% recyclate and 30% virgin material. There are several materials in the range – both homopolymers and co-polymers – with various melt flow index and mechanical strength values. In the area of tethered caps, the company says


its Eltex materials have high stress crack resistance (ESCR), good organoleptic properties (no smell) and good processability. They are already used in applications for suppliers including Bericap and Tetrapak.


Consumer drive Henkel is a huge consumer brand, with adhesives, detergents and personal care products among its many offerings. Like many large companies, it has sustainability targets – such as making all packag- ing recyclable or reusable, cutting the use of fossil-based plastics and banishing plastic waste. Ingomar Henning, global injection moulding manager at Henkel in Germany, said the company used around 625,000 tonnes of packaging materi- als in 2023, of which around 45% was plastics. Within its consumer division, it used around 200,000 tonnes/year of plastics – of which nearly one-fifth was injection-moulded PP. Part of its approach is to redesign packaging – such as making ‘shoulderless’ tubes in which the cap is smaller than before. In one specific example, it relaunched its Schauma shampoo and conditioner brand in 2022. For one shampoo packaging, closure weight was reduced by 3%, to 6.4g – while PCR content went from 0% to 25%. For a conditioner, the cap weight was cut by 15% to 5.9g while PCR content was increased from 0% to 25%. The company compared a range of virgin,


partially recycled and recycled materials. Virgin PP required an injection pressure of 400 bar, for instance; an equal mix required 480 bar; and a 98% rPP needed 520 bar. At the same time, capping forces were 105, 142 and 146N, respectively. For an HDPE, a virgin grade needed 750 bar of injection pressure, an equal mix 1300 bar, and a 98% rHDPE 1650. Another cap innovation – in laundry gel – was to


go from a spout and dosing cap (23.8g) to dosing cap (11g) to a flat cap (5.4g). The total saving in virgin plastic is 77%. The company has also carried


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out impact tests on caps – such as its Perwoll laundry gel. Here, it found that a PP-homopolymer cap passed a critical drop test, while materials such as HDPE, LDPE and PP-RBC were either inferior or more expensive.


Seasonal eating Kaho Tanaka, a designer at Nippon Closures in Japan, told delegates about the company’s closures – whose pouring and powdering function help to increase the product’s own value. Here, the closures are used in seasoning


products such as soy sauce and other condiments. As well as needing good sealing performance – to preserve the product – the closure needs to pour smoothly. Another critical factor is oxidation, which accelerates the degradation of the product. “We have developed innovative pouring caps,”


she said. One is a new type of spray cap that moves away


from the traditional multi-components – and multi-material – design, to a three-part, mono-mate- rial design. It comprises a nozzle – to suck up the sauce – as well as a cup to store the sauce, and a hinge cap. Here, a small amount of sauce is sucked into the cap and dispensed – ensuring minimal oxidation.


It has also developed a three-part powder cap


that has a two-sided hinge cap – one side of which includes a ‘mesh’ that sifts the powder as it is dispensed. It is used for ingredients such as powdered sugar, flour and cocoa. “Our pouring cap can increase the product’s own value,” she said.


Closed market Aptar Closures has a wide portfolio of products, including snap tops, tube tops, pouring spouts, safety caps and many others. It says that 80% of consumers feel that sustainability is important.


Above: Henkel used around 40,000 tonnes/ year of injection- moulded PP in 2023


� March/April 2025 | INJECTION WORLD 17


IMAGE: SHUTTERSTOCK


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