Highly transparent barrier beer bottle

Netstal's PET-LINE 96N injection molding machine is equipped with a melt reservoir and a newly developed liquid color material metering device using modified PET (PolyShieldTM material supplied by Swiss Invista) and a PA barrier material (by Japan Mitsubishi's MXD6) blends are used to make beer preforms. The resulting product not only has excellent barrier properties to O2 and CO2, but also has excellent transparency.

In the past, the use of a mixture of PET and barrier plastics (such as relatively expensive PET-PEN or somewhat cheaper PET-PA) to produce multi-layer preforms or inner surface-coated preforms often resulted in poor transparency or dark colors. Such phenomena as imperfections, and thus this technique has not been widely promoted. The mixture of PolyShieldTM and MXD6 (about 2%) currently on the market (PolyShieldTM/MXD6) solves the problems encountered in previous production technologies and can meet the high transparency of O2 barrier layer in most applications. Claim.

The launch of PolyShieldTM/MXD6 has provided a very good barrier solution for the beer packaging industry, and it can maintain the original taste of beer well. According to the Berlin VLB study, there was no difference in taste when beer was placed in beer bottles and glass bottles (capacity of 0.5 L) made using PolyShieldTM/MXD6 for 6 months. In addition to the barrier properties caused by PA particles, PolyShieldTM/MXD6 also blocks O2. It is said that about 5% of MXD6 can play a role in blocking CO2, and CO2 loss is less than 15% within 4 months. Dr. Karsten Fritsch, Invista's technical service manager, pointed out that the biggest difference between the transparent PolyShieldTM/MXD6 hybrid material and the conventional PET-PA hybrid material is the size of the PA particles in the hybrid material. Compared to the PET-PA hybrid material, the PA particles mixed in the PolyShieldTM/MXD6 hybrid material are much smaller and therefore more transparent.

Under normal circumstances, the PET-LINE 96N injection molding machine can process this raw material mixture directly using a standard screw. According to Stefan Bock, Netstal's application manager of the PET system application department, a 135 mm diameter screw (with a plasticizing capacity of 1050 kg/h) is used for the first time in the production of such preforms, with a plasticization capacity of 110 mm. The screw is much higher, allowing the device to produce a 96-cavity, 39.1-g preform in a 13-second cycle. This means that about 26,600 preforms per hour are produced from a PET-LINE 96N injection molding machine (mold produced by Otto Hofstetter AG). This specially developed continuous plasticizing process allows the screw to rotate continuously at a constant rotational speed. Combined with a 6.6 kg melt reservoir, a very uniform melt quality (AA value below 4 ppm) can be achieved. After the solids were injected, the amber liquid was injected into the injection molding apparatus via a color mixing device called "Gold Amber 3". The advantage of this special self-cleaning injection molding system is that there is no longer a phenomenon that the screw idling due to the effect of the pigment and causes fluctuations in the output or a decrease in production. In addition, when using PolyShieldTM/MXD6 materials to produce single-layer PET beer preforms, Netstal's high-yield PET-LINE 96N injection molding machine can provide completely transparent barrier layers according to customer requirements, and is particularly suitable for the production of various colored preforms.

Source: MM Modern Plastics