Polypropylene was the first manufactured material used in baler twine. It was much stronger than sisal but softer and less brittle, making it suitable for larger hay bales or other materials. The technology for polypropylene continued to develop rapidly, and today, a wide range of artificial plastics are used for making baler twine. This twine is usually made of smaller fibre strands but may also be a monofilament. The tensile strength of square bales can require the use of thicker twine than their round counterparts. It is because square bales are larger and more pressurised than round bales. Therefore, choosing twine with a tensile strength of around 130 to 450…