Netting
OwnerAnthony Bramley, Robin J. T. Clabburninventors
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Abstract
Netting formed of longitudinal and transverse threads of thermoplastic material bonded at the thread crossings by individual moulded buttons of thermoplastic material is improved by the use of threads that have been subjected to irradiation to cross-link their thermoplastic material. Higher moulding temperatures can be used in the formation of the bonding buttons, for example in the case of polyethylene filaments up to 260.degree. C or more, and increased bond strength between the crossing threads is achieved. The moulded buttons can also be formed of irradiated material.
Claims11
Netting comprising longitudinal threads of thermoplastic material and transverse threads of thermoplastic material joined together at the thread crossings by individually molded masses of plastic material, in which the material of the threads has been irradiated to cross-link such material prior to molding of the masses at the thread crossings and molding of such masses was carried out at a molding temperature above that at which softening or heat damage occurs in the same material not treated by irradiation but below a temperature damaging to the irradiated thread material.
A method of making netting by drawing transverse threads of synthetic thermoplastic polymer material across longitudinal threads of synthetic polymer material and bonding the threads together by moulding individual masses of thermoplastic polymer material at the thread crossings in which the improvement comprises subjecting the material of the threads to irradiation to cross-link the thermoplastic material thereof prior to the moulding of the masses at the thread crossings and thereby increasing the strength of bonding at the thread crossings.
A method of making netting by drawing transverse threads of synthetic thermoplastic polymer material across longitudinal threads of synthetic thermoplastic polymer material and bonding the threads together by moulding individual masses of thermoplastic polymer material at thread crossings, in which the improvement comprises:
- subjecting the material of the threads to irradiation to cross-link the thermoplastic material thereof prior to the moulding of the masses at the thread crossings and thereby increasing the strength of bonding at the thread crossings, and setting the moulding temperature at a level above that at which softening or heat damage occurs in the same material untreated by irradiation but below a temperature damaging to the irradiated thread material, and thereby further increasing said bond strength.
In a method of making netting including the steps of drawing transverse threads of synthetic thermoplastic polymer material across longitudinal threads of synthetic thermoplastic polymer material, moulding individual masses of heated thermoplastic polymer material about the threads at their crossing points, and hardening the masses to bond same to said threads and thereby bonding the crossing threads together, increasing the strength of the bond between crossing threads by the additional steps comprising:
- irradiating the material of the threads to cross-link the thermoplastic material thereof prior to said step of moulding of the masses of the thread crossings, thereby increasing both said bond strength and the heat resistance of the thread material;
- setting the moulding temperature at a level above that at which bond strength for unirradiated threads of the same thermoplastic material starts to decrease from maximum, and thereby further increasing said bond strength;
- and
- increasing shrinkage of said masses upon cooling in said hardening step by irradiating the material of said masses prior to said moulding step, and thereby still further increasing said bond strength.
In a method of making netting including the steps of drawing transverse threads of synthetic thermoplastic polymer material across longitudinal threads of synthetic thermoplastic polymer material, moulding individual masses of heated thermoplastic polymer material about the threads at their crossing points, and hardening the masses to bond same to said threads and thereby bonding the crossing threads together, increasing the strength of the bond between crossing threads by the additional steps comprising:
- forming said thread from polyethylene filaments;
- irradiating the material of the threads to cross-link the thermoplastic material thereof prior to said step of moulding of the masses of the thread crossings, thereby increasing both said bond strength and the heat resistance of the thread material and in which the irradiation of the thread material is carried out with an irradiation dose of 15 - 25 MRADS;
- increasing shrinkage of said masses upon cooling in said hardening step by irradiating the material of said masses prior to said moulding step, and thereby still further increasing said bond strength.
Dependencies are inferred from the claim text.