CHEMICAL-TECHNOLOGICAL PRECONDITIONS FOR DIGITAL TWIN IMPLEMENTATION IN POLYMER PROCESSING: A DOCUMENTED TECHNOLOGY BASELINE FROM BULGARIAN PLASTICS

Digital Twin technology is increasingly proposed for polymer processing, yet the chemical-technological conditions that make a twin useful, and the equipment baseline required to build one, are rarely examined together against documented industrial evidence. This paper establishes why polymer processing is a favourable domain for Digital Twin implementation and then tests how far the necessary preconditions are met in a national producing sector. The argument proceeds from polymer physics. Because melt viscosity is strongly shear- and temperature-dependent, and because thermal history governs crystallization, shrinkage and residual stress, a fixed set of machine settings does not reproduce a fixed process state when polymer grade, recycled fraction, moisture content or additive level varies. A twin is valuable in this domain precisely because the state variables that determine part quality cannot be measured directly in production. Against this background, a technology inventory was compiled for a census of 29 Bulgarian plastics manufacturers (NACE 22.2x), of which 20 firms have documented process-level evidence. Extrusion is documented at 13 of the 20 firms, injection moulding at 5 and internal recycling at 4, with thermoforming, coating and blow moulding at 1 - 2 firms each; 7 of the 20 firms disclose named equipment. Sensor-level process instrumentation is documented at no firm, and no firm provides evidence of an ERP, MES or SCADA system, or of a Digital Twin. On the classification applied here, no firm falls in the confirmed Digital Twin category and three fall in the Digital-Twin-ready category. The binding constraint in this sector is therefore not modelling capability but the absenceof the in-process measurements – melt temperature, melt pressure, cavity pressure and screw torque - from which any twin state estimate must be constructed. Firms processing recycled feedstock have the strongest technological case for instrumenting first.