THREE PRIME FACTORS IN SUCCESSFUL PACKAGING 13 highly wfiatile, and this type of liner is quite generally used f•,r jar covers. Pulpboard is light in color and has been used in the past for lining semi-translucent urea form- aldehyde caps in order not to cause two shades in the cap, as mentioned previously. Currently, pulpboard is very diflScult to obtain, stocks in this country being now practically non-existent. Should the facing material be broken due to a fin on the glass container or due to pene- tration or action by the product, and pulpboard or newsboard be used as a backing, loss of product will result. Cork composition is, in it- self, a satisfactory liner for many products where the shelf life is short. With ,added protection from the facing, cork composition, though , more expensive, produces the most efiScient seal. Should the facing be , ruFtured or impaired, the cork corn- .position then acts as a secondary seal. The usual cork compositions tare produced from granulated cork land a'protein binder. Where indi- leated, cork compositions can be i supplied with a resinous binder. The facing materials for liners are I the metallic foils, varnished papers i or synthetic films. Tinfoil, 99.7% I pure, 0.0015" thick, mounted on • white sulphite paper, has been used If or organic solvents and alcohol- , containing preparations. Such a i liner is indicated for nail polish re- movers, perfumes, colognes, and i products which do not etch or attack the foil. If the finish and sealing surface of the glass container is in good condi.tion, newsboard may t)e used as a backing otherwise, cork composition is indicated. Cur- rently, Tinfoil is unobtainable for such products, and during the war a urea formaldehyde-alkyd coating on paper producing a varnished paper type of liner was used. This liner is definitely inferior to Tinfoil, but was used during the emergency. Dead soft Aluminum Foil, 0.001" thick, backed with cork composi- tion, has been tried as a substitute for Tinfoil with rather poor results, due to the fact that the Aluminum Foil is not as soft as Tin, and does not give intimate contact with the glass and prevent evaporation. The manufacturers are currently attempting to produce Aluminum Foil with an organic coating such as Vinylire applied to the face. Early tests have indicated that an eflScient liner will result if the product does not dissolve the organic coating which has been applied to the Aluminum Foil. The varnished papers--which are _}ust what their name implies, name- ly, a varnish applied to a supporting paper or several coats of varnish being built up to yield the necessary thickness--•have been used for many years as facings. There are many types, such as Pale Yellow Oil, Yellow Oil or Light Brown Oil, Black Alkali Paper, Harvel, Brown Acid Resisting Paper, 8018, etc. The varnished papers have fair moisture-vapor transmission char- acteristics and are satisfactory for aqueous products and cold creams. Black Alkali Paper will withstand 50% alcohol solutions, although the

14 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS varnished papers are definitely attacked by essential oils or prod- ucts containing the essential oils. A wax coating applied to the varn- ished paper improves the moisture transmission characteristics, though the wax tends to hold carton dust, and the dust developed in manufac- turing operations, and may at times flake and show up as floating parti- cles on the product. Vinylire, the copolymer of vinyl acetate and vinyl chloride plasti- cized and pigmented, hak been applied to a white sulphite paper to produce an excellent facing material and has enjoyed quite general use. The Vinylire resin is dissolved by the ketones, consequently it cannot be used with nail polish or nail polish removers and is attacked by certain perfumes. Vinylire has good mois- ture-vapor transmission character- istics. During the (var period, this lining material was decidedly scarce, although it is currently available in reasonable amounts. Before the war, Panaseal was a very active competitor of Vinylire. It consists of the product Pliofilm (a rubber hydrochloride compound) mounted on white sulphite paper. This material was also soluble in the ketones and in the chlorinated hydrocarbons, as well as the hydro- carbons, and was attacked by cer- tain perfumes. It has good mois- ture-vapor transmission character- istics, and was used in jar covers for cold creams. A urea formaldehyde-alkyd resin type of varnish was applied to white sulphite paper by several concerns under the trade names Silite, White- seal and Impervite, and used as a replacement for Tinfoil, Vinylire and Panaseal during the war. The film is inclined to be somewhat brittle and does not have much stretch. It is best used with a non- resilient type of backing such as newsboard, and is used as a sub- stitute for Tinfoil in many applica- tions. The newer synthetic resins such as Saran, Polythene and Nylon will, in the future, enter the liner field. At the present time they are either too expensive, have not been pro- duced in sufficiently thin films, or have too great odor or taste trans- mission tendencies. They do have some admirable resisting character- istics, and a serious effort is being made to utilize them for the de- velopment of a more nearly uni- versal type of liner. Some concerns have used waxed pulpboard as a liner for cold creams. This is probably as cheap a light colored liner as can be obtained. Its efficiency is low and its moisture- vapor transmission characteristics also are poor. Saturatedpulpboard consists of pulpboard impregnated with a wax and oil combination. This type of liner has been used for cold creams, and is better than the waxed pulp, but is really not ideal. Quality white waxed paper consists of white sulphite paper with an application of paraffin or micro- crystalline waix. It has been used mounted on p. ulpboard or on satu- rated pulpboard, and has fair mois- ture-vapor transmission character-