Plastics slip additives

Slip additives act at the surface of a polymer film or article to reduce the friction between it and another surface. In a variety of plastics, such as polyolefins, polystyrene, and polyvinyl chloride, fatty-acid amides are applied as slip additives. Fatty-acid amides, such as oleamide, stearamide, erucamide, and oleyl palmitamide, are added to plastic formulations where they gradually tend to bloom to the surface, imparting useful properties including lubrication, prevention of films sticking together, and reduction of static charge. 

R. Moreno, The Role of Slip Additives in Tape-Casting Technology Part II - Binders and Plasticizers , Am Ceram. Soc. Bull., 71 [11] 1647-57 (1992). 

P Patel and N Savargaonkar, "A Review of Additives for Plastics Slips and Antiblocks" Plastics Engineering, Society of Plastics Engineers, January 2007. 

Use Slip additives for PVC and polyolefin resin films, antistatic and antifogging agent for clear plastic wraps, and as internal lubricants. 

Removal of surface acting substances from plastics, e.g. lubricants, slip additives, such as stearamide, stearates, anti-static agents. 

Other surface active ingredients which may be found in plastic materials and suffer loss into product by solution, surface abrasion, etc. include anti-static additives, slip additives, mould release agents, etc. 

Patel P, Savargaonkar N. A review of additives for plastics slips and antiblocks. Plastics Eng [trade journal—Society of Plastics Engineers] January 2007. 

Constant DR, Jester RD. Cyclic-olefinic copolymers as non-migrating polymeric slip additives in LDPE cast films. ANTEC 2002, conference proceedings. Society of Plastics Engineers January 2002. 

Moreno R (1992) The role of slip additives in tape casting technology, 2. Binders and plasticizers. Am Ceram Soc Bull 71 1647-1657... 

An external antistat is applied via a carrier medium to the surface of the plastic part. The same considerations and limitations apply as with nonmigrating slip additives. Conductive filler is incorporated into the organic substrates and builds up a conductive network on a molecular level. While both approaches are used in organic substrates, they are not the most common. 

An internal antistat is compounded into the organic substrate and migrates to the plastic part surface. The same principle considerations apply as for migrating slip additives (Figure 1.19). 

Slip additives are used with packaging plastics such as polyolefins, polystyrene and PVC to impart lubrication, prevent films (such as cling-film) from sticking together and to reduce static charges. They are usually surfactants such as fatty add amides which have the desired rate of blooming to the polymer surface where their action is needed. 

Tospearl has been used as a plastic film additive in polypropylene (PP). A specific example is shown in Table 5 where Tospearl 120 was incorporated into a single PP sheet. One third less Tospearl was required when compared to silica to obtain the same antiblocking properties. In addition, the static slip was half as large. 

It is common for aliphatic amides to be incorporated into plastics, particularly polyethylenes, to act as slip additives. 

It is possible to use LC-MS to detect these types of slip additives in plastic samples. Using the LC-MS conditions described in Section 6.2, it is possible to detect Behenamide (mixture of two aliphatic amides of molecular weight 331 and 339) and erucamide (molecular weight 337) in solvent extracts of polyethylene and polypropylene. 

It is also possible to use GC and GC-MS to analyse these and another common slip additive oleamide in extracts from plastics as they have sufficient volatility to elute from the GC column. 

Another application of SIMS is in the study of the migration of additives (e.g., slip additives and antistats) onto the surface of plastics. 

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