Abstract A security paper is provided in which identifying material is contained as an intercalary layer within the thickness of a bonded, nonwoven, polyethylene-film-fibril sheet having an opacity of at least 70% and a delamination resistance of at least 60 grams per centimeter. A process for making such paper includes forming an assembly of two unbonded, lightly consolidated, nonwoven, polyethylene film-fibril sheets containing identifying material between them, compressing the assembly in an unheated nip at 17 to 85 kilograms per centimeter of assembly width and then self-bonding the compressed assembly while under restraint by contact with a heated drum. Such security paper is useful for bank notes, stock certificates, paper currency and the like.
An improved security paper of the type made from bonded webs containing thermoplastic fibers and an intercalary layer of identifying material, the improvement comprising webs consisting essentially of self-bonded nonwoven polyethylene film fibrils, said webs and intercalary layer having been assembled under a cold compression of at least 17 kg/cm of assembly width during manufacture of the paper, and the paper having an opacity of at least 70% and a delamination resistance of at least 60 grams per centimeter in the plane of the layer containing the identifying material.
Claim 2
Dependent Claim
89 words
An improved security paper of the type made from bonded webs containing thermoplastic fibers and an intercalary layer of identifying material, the improvement comprising webs consisting essentially of self-bonded nonwoven polyethylene film fibrils, said webs and intercalary layer having been assembled under a cold compression of at least 17 kg/cm of assembly width during manufacture of the paper, and the paper having an opacity of at least 70% and a delamination resistance of at least 60 grams per centimeter in the plane of the layer containing the identifying material.
Claim 3
Dependent Claim
104 words
A security paper in accordance with claim 1 wherein the paper has a basis weight of 50 to 150 grams per square meter, a tensile strength of at least 100 grams per centimeter per g/m 2 , a toughness of at least 25 centimeter-grams per square centimeter per g/m 2 , an Elmendorf tear of at least 3 grams per g/m 2 , and a surface abrasion resistance of at least 5 and the identifying material is a colored material in the form of discrete fibers or particles of film which material amounts to no more than about 0.5 weight percent of the paper.