Anti-bac:

an additive which inhibits the growth of certain bacteria. Various types are available – the most common containing trychlosan depending on the type of bacteria targeted.

Anti-block:

an additive which prevents blocking (see below)

Anti-stat:

an additive which reduces the static electricity present in most finished plastic goods (caused by friction generated during processing). This ‘static’ is most apparent in very thin films – particularly HDPE.

Biodegradable:

a material which will degrade through microbial action – generally in the earth or in landfill sites. There is considerable discussion, indeed controversy, as to the definition of this term. Various additives are available to accelerate this process under certain conditions.

Block-headed:

a stack (or block) or bags or carriers (normally 50 or 100) attached to a header strip by a perforated line enabling them to be torn off one at a time. The header strip is normally punched with 2 holes, so that the block can be placed on hooks for convenience.

Blocking:

a condition affecting mainly LDPE and LLDPE bags, where 2 layers of film stick to each other, making the bag difficult (or in extreme cases, impossible) to open. Bags in this state are ‘blocked’.

Centre Fold Sheet(ing) [CFS]:

the same as ‘lay flat tubing’ but with a slit on 1 edge.

Compostable:

a material which will fully degrade in the specific conditions of a compost heap with the presence of certain defined chemicals and/or microbes.

Corona Discharge Treatment:

the film is passed through a device which changes the surface resistivity of the film (effectively scuffing the film electrically), so that ink, adhesives etc. can be applied to the film more easily.

Double Wound Sheeting (DWS):

a double layer of film wound on to a reel – made by slitting layflat tubing on both edges and winding on to 1 reel.

Edge-trimmed:

the edges of single wound or double wound sheet film are slit by fixed blades so that the width of the film is accurate to 2mm. This is more expensive than standard film because of the wasted trim and should only be specified when accurate width is essential.

Embossed:

a series of small indentations in the film give a cosmetic effect.

EVA:

added to polythene film to improve puncture resistance, sealability and surface strength.

Flame Retardant:

an additive which reduces the flammability of a material.

Fragrance:

in plastics, this is an additive to give the material a scent (e.g. lemon) which is incorporated into the material itself during processing, rather than being applied to the outer surfaces after processing.

Gauge:

imperial equivalent of micron, 1/1000th of an inch (0.001″), thus 1 micron = 4 gauge etc (approx.)

Gusseted layflat tubing (GLFT):

layflat tubing with the edges tucked in

High Slip:

an additive which makes film more slippery (desirable in some applications, undesirable in others)

J Fold Sheeting (JFS):

similar to centre fold sheeting, but slit at a point not on the edge – mainly used for making side weld bags with a lip.

Layflat Tubing (LFT):

a tube of material which is squashed flat and wound on to a reel.

Metalocenes:

a fairly new member of the polythene family – excellent clarity and strength, but difficult to extrude and process.

Micron:

a linear measurement, 1/1000 of 1mm (0.001mm).

Microperforated:

a series of tiny holes in the film, making it pervious to air and other gases.

Photodegradable:

a material which will degrade in sunlight. All polyethylenes eventually degrade in this way and photodegradable additives considerably accelerate this process.

Recycled:

a processed plastic which has been used for its intended purpose and subsequently reworked.

Reprocessed:

a processed plastic which has not been used (e.g. factory waste) and subsequently reworked.

Single Wound Sheeting (SWS):

a single layer of film wound on to a reel – made by slitting layflat tubing on both edges and winding on to 2 reels.

Treatment/Treated:

see corona discharge treatment

UV Stabliser:

an additive which reduces the tendency of plastic materials to photodegrade as a result of ultraviolet rays (i.e. sunlight).