The invention concerns a process for producing a security film, comprising: forming a polymeric film substrate having first and second surfaces and comprising one or more migratory additives; plasma treating at least a part of at least one surface of the polymeric film substrate; and promptly contacting a foil with the at least one part of the plasma treated surface of the polymeric film substrate such that the foil adheres to the polymeric film substrate.

The invention concerns a process for producing a security film, comprising: a. forming a polymeric film substrate having first and second surfaces; b. plasma treating at least one surface of the polymeric film substrate using a modified atmosphere plasma treatment, wherein the modified atmosphere comprises at least one inert carrier gas and at least one functional material selected from: i. one or more oxidising fluids; ii. one or more reducing fluids; and iii. one or more polar fluids with the capacity to form ionic or covalent bonds with the at least one surface of the polymeric film substrate, wherein those oxidising fluids with a relative dielectric strength less than that of air, where present, are in the modified atmosphere in an amount less than 40% by weight or by volume; and c. contacting a foil with the at least one plasma treated surface of the polymeric film substrate such that the foil adheres to the polymeric film substrate.

A method for producing a printed material includes forming a color image having an image area ratio of 20% or less on a peripheral edge portion of a recording medium by using a coloring material; providing pressure-induced phase transition particles to a region of the recording medium, the region including the peripheral edge portion; bonding the color image and the pressure-induced phase transition particles onto the recording medium; and folding the recording medium having the color image and the pressure-induced phase transition particles bonded thereon and pressure-bonding the folded recording medium, or pressure-bonding the recording medium having the color image and the pressure-induced phase transition particles bonded thereon and another recording medium placed on top of each other. The pressure-induced phase transition particles contain a styrene resin and a (meth)acrylic acid ester resin, the styrene resin contains styrene and a vinyl monomer other than styrene as polymerization components, the (meth)acrylic acid ester resin contains at least two (meth)acrylic acid esters as polymerization components, and a mass ratio of the (meth)acrylic acid esters is 90 mass % or more of a total of all polymerization components of the (meth)acrylic acid ester resin. The pressure-induced phase transition particles have at least two glass transition temperatures, and a difference between the lowest glass transition temperature and the highest glass transition temperature among the glass transition temperatures of the pressure-induced phase transition particles is 30 C. or more.

A method for producing a printed material includes forming a color image having an image area ratio of 20% or less on a peripheral edge portion of a recording medium by using a coloring material; providing pressure-induced phase transition particles to a region of the recording medium, the region including the peripheral edge portion; bonding the color image and the pressure-induced phase transition particles onto the recording medium; and folding the recording medium having the color image and the pressure-induced phase transition particles bonded thereon and pressure-bonding the folded recording medium, or pressure-bonding the recording medium having the color image and the pressure-induced phase transition particles bonded thereon and another recording medium placed on top of each other. The pressure-induced phase transition particles contain a styrene resin and a (meth)acrylic acid ester resin, the styrene resin contains styrene and a vinyl monomer other than styrene as polymerization components, the (meth)acrylic acid ester resin contains at least two (meth)acrylic acid esters as polymerization components, and a mass ratio of the (meth)acrylic acid esters is 90 mass % or more of a total of all polymerization components of the (meth)acrylic acid ester resin. The pressure-induced phase transition particles have at least two glass transition temperatures, and a difference between the lowest glass transition temperature and the highest glass transition temperature among the glass transition temperatures of the pressure-induced phase transition particles is 30 C. or more.

Aspects of the present disclosure relate to a security device, in particular, a multilayered security device. The multilayered security device includes a substrate layer having a first substrate. The substrate layer attaches to the product. The multilayered security device also includes a graphene layer. The graphene layer has a first continuous graphene sheet that is made of a monolayer of covalently-bonded carbon atoms. The graphene layer also forms, in response to exposure to a verification stimulus, a contrasting pattern with respect to an exposed substrate area from the substrate layer.