High Tensile Bags

Introduction

picture of high tensile bags

High Tensile bags/film have improved strength properties compared to standard polybags/polythene film at a given thickness therefore saves material and cost.

High tensile bags/film are also known as 'HT' or 'high strength' bags/film.

This bags are highly popular in meat/food packaging industry. HT bags are ideal where extra bag strength or thickness reduction is required.

How it is made?

High tensile (HT) bags are generally made using blend of two or more polythene to achieve desired physical properties.

Single-layer(mono)'HT' films would be a blend of low and medium density polythene. However, 'HT' film is also made using co-extruded technology.

Major UK suppliers:

Product specification

Common materials used for 'High Tensile'(HT) bags:

  • Low density polythene (LDPE)
  • Linear low density polythene (LLDPE)
  • Medium density polythene (MDPE)
  • Recycled polythene

Available Thickness:

80 Gauge(20microns) to 250 Gauge(62.5microns)

Tolerances:

Normally, 'High Tensile(HT) bags' in Great Britain should follow widely accepted industrial standards according to British Standard - see BS7344, 1990

  • Width: Plus or minus 3mm (0.125") or 2% whichever is greater
  • Length: Plus or minus 6mm (0.25") or 2% whichever is greater
  • Gauge: Plus or minus 10%

Standards for 'High Tensile(HT) bags' to use for food contact and medical application:

Food Contact – To use High Tensile(HT) bags inside European Union, in contact with food should comply with the relevant legislation on food contact including Great Britain.

  • Great Britain: Statutory Instrument, 1998 No. 1376 and BPF-BIBRA (1995), Polymer Specification 4, Polyethylene
  • EU: Commission Directive 90/128/EEC, 92/39/EEC, 93/9/EEC, 95/3/EEC and 96/11/EC, Section A.
  • Example of a company comply with food contact: Polybags Limited

Medical use – Similarly, to use High Tensile(HT) bags inside European Union, to produce containers for preparations for medico-pharmaceutical purposes should comply with the following regulation:

  • European Pharmacopoeia - Monograph 3.1.3 "Polyolefin's" for medico-pharmaceutical purposes.
  • The final responsibility for the decision of whether a material is fit for a particular application lies with the pharmaceutical firm.
  • Example of a company comply with medical use: Polybags Limited

Options for High tensile(HT) bags

Material

  • Low density polythene (LDPE)
  • Linear low density polythene (LLDPE)
  • Medium density polythene (MDPE)
  • Co-extruded

Appearance

  • Light/Tint coloured
  • Opaque coloured
  • Clear

Plain or printed 'High Tensile(HT) bags'

  • Plain
  • Printed in 1 colour
  • Printed in 2 colour

Variety of 'High Tensile'

  • Individual HT Bags
  • Block headed with hanging holes for easy tear off - HT bags
  • HT bags perforated on roll
  • Single wound sheeting
  • Centrefold Sheeting
  • Gusseted bags
  • Layflat tubing

Common areas of application for High tensile bags or film

  • Any packaging where you need strength
  • Meat packaging
  • Food packaging
  • Heavy duty shipping sacks
  • Builders roll
  • Sanitary packaging

Advanced features of High tensile strength (HT) film

  • Extra strength yet lightweight - Very high tensile strength up to 35MPa (up to 50% stronger than standard polythene film of the same thickness)
  • Food use approved
  • Greater flexibility and improved toughness
  • Good tear/puncture resistance
  • Lower cost (thinner film but tougher performance saving both material and cost)
  • Films are easy opening, non blocking films making them quick to open ready for filling (saves time)
  • Recyclable

Definition of terms used in High tensile(HT) bags or film:

  • Tensile strength:- The tensile strength of a material is the maximum amount of tensile stress that it can be subjected to before the material breaks. It is measured in MPa (mega Pascal)
  • Toughness:- It is the resistance of a material to fracture or break
  • Impact strength:- Energy required to fracture a specimen subjected to shock loading, as in Impact test.
  • Puncture resistance:- Extent to which a material is able to withstand the action of a sharp object without perforation.

Common sizes

News - Polybags launches High Tensile film

Recent environmental initiatives

  • New fully degradable polyfilm grade launched March 2006
  • New external Polymer Silos operational December 2005 to store and transfer different polymer grades more economically and without need for pallets or baling sacks
  • New down gauging films launched Autumn 2005 ['HT' and 'High Melt' grades] to enable identical film strength but at thinner gauges saving customers both material and cost
  • We moved away from Company Car Scheme Incentives in Summer 2004
  • £45,000 upgrade of Recycling Capabilities in spring 2004 to enable production of 200kg/hr of reprocessed polymer
  • Major electrical upgrade in 2003 and installation of flow regulator to smooth electrical usage
Reference: https://www.polybags.co.uk/environ.htm