A printed material includes: a recording medium having a pressure-bonding surface on which an image portion and a pressure phase transition layer are formed, the recording medium being folded upon the recording medium and pressure-bonded; or a recording medium having a pressure-bonding surface on which an image portion and a pressure phase transition layer are formed and an additional recording medium, the recording medium and the additional recording medium being stacked and pressure-bonded together. The average thickness of the pressure phase transition layer formed on the image portion on the pressure-bonding surface of the recording medium is larger than the average thickness of the pressure phase transition layer formed on a non-image portion on the pressure-bonding surface of the recording medium.

A method for producing a composite resin particle dispersion includes: polymerizing a (meth)acrylic acid ester compound to form a (meth)acrylic acid ester-based resin; and polymerizing a styrene compound and a vinyl monomer other than the styrene compound in the presence of the (meth)acrylic acid ester-based resin to form composite resin particles containing a styrene-based resin and the (meth)acrylic acid ester-based resin. The mass ratio of the styrene-based resin to the (meth)acrylic acid ester-based resin in the composite resin particles is from 80:20 to 20:80. A difference between the lowest glass transition temperature and the highest glass transition temperature in the composite resin particles is 30° C. or more.

A method for producing a composite resin particle dispersion includes: polymerizing a (meth)acrylic acid ester compound to form a (meth)acrylic acid ester-based resin; and polymerizing a styrene compound and a vinyl monomer other than the styrene compound in the presence of the (meth)acrylic acid ester-based resin to form composite resin particles containing a styrene-based resin and the (meth)acrylic acid ester-based resin. The mass ratio of the styrene-based resin to the (meth)acrylic acid ester-based resin in the composite resin particles is from 80:20 to 20:80. A difference between the lowest glass transition temperature and the highest glass transition temperature in the composite resin particles is 30° C. or more.

A method for producing pressure-responsive particles includes: adding an aggregating agent to a dispersion containing composite resin particles containing a styrene-based resin including a styrene compound and a vinyl monomer other than the styrene compound as polymer components and a (meth)acrylic acid ester-based resin including a (meth)acrylic acid ester compound as a polymer component to aggregate the composite resin particles so as to form aggregated particles A; forming a shell by adding an aggregating agent and styrene-based resin particles containing a styrene compound and a vinyl monomer other than the styrene compound as polymer components to a dispersion containing the aggregated particles A to aggregate the styrene-based resin particles so as to form aggregated particles B; and heating and fusing the aggregated particles B to form pressure-responsive particles. The amount of the styrene-based resin particles added in the formation of the shell is 5 mass % or more and 40 mass % or less relative to the total mass of the composite resin particles. The amount of the aggregating agent added in the formation of the shell is 0.1 mass % or more and 1.0 mass % or less relative to the total mass of the composite resin particles. The mass ratio of the styrene-based resin to the (meth)acrylic acid ester-based resin in the pressure-responsive particles is from 80:20 to 20:80. A difference between the lowest glass transition temperature and the highest glass transition temperature of resins contained in the pressure-responsive particles is 30° C. or more.

A method for producing pressure-responsive particles includes: adding an aggregating agent to a dispersion containing composite resin particles containing a styrene-based resin including a styrene compound and a vinyl monomer other than the styrene compound as polymer components and a (meth)acrylic acid ester-based resin including a (meth)acrylic acid ester compound as a polymer component to aggregate the composite resin particles so as to form aggregated particles A; forming a shell by adding an aggregating agent and styrene-based resin particles containing a styrene compound and a vinyl monomer other than the styrene compound as polymer components to a dispersion containing the aggregated particles A to aggregate the styrene-based resin particles so as to form aggregated particles B; and heating and fusing the aggregated particles B to form pressure-responsive particles. The amount of the styrene-based resin particles added in the formation of the shell is 5 mass % or more and 40 mass % or less relative to the total mass of the composite resin particles. The amount of the aggregating agent added in the formation of the shell is 0.1 mass % or more and 1.0 mass % or less relative to the total mass of the composite resin particles. The mass ratio of the styrene-based resin to the (meth)acrylic acid ester-based resin in the pressure-responsive particles is from 80:20 to 20:80. A difference between the lowest glass transition temperature and the highest glass transition temperature of resins contained in the pressure-responsive particles is 30° C. or more.

A pressure sensitive adhesive includes: composite resin particles that contain a styrene resin containing, as polymerization components, styrene and a vinyl monomer other than styrene, and a (meth)acrylate resin containing, as a polymerization component, a (meth)acrylate; and an aqueous solvent containing water, in which a mass ratio of the styrene resin to the (meth)acrylate resin (styrene resin:(meth)acrylate resin) is 80:20 to 20:80, a difference between the lowest glass transition temperature and the highest glass transition temperature of the composite resin particles is 30° C. or more, a melt viscosity of the composite resin particles at 100° C. is 4000 Pa.Math.s or more and 20000 Pa.Math.s or less, and, in a melt viscosity range of the composite resin particles of 4000 Pa.Math.s or more and 20000 Pa.Math.s or less, a slope of a logarithm of the melt viscosity of the composite resin particles relative to a temperature of the composite resin particles is −0.08 or more and −0.04 or less.

A pressure sensitive adhesive includes: composite resin particles that contain a styrene resin containing, as polymerization components, styrene and a vinyl monomer other than styrene, and a (meth)acrylate resin containing, as a polymerization component, a (meth)acrylate; and an aqueous solvent containing water, in which a mass ratio of the styrene resin to the (meth)acrylate resin (styrene resin:(meth)acrylate resin) is 80:20 to 20:80, a difference between the lowest glass transition temperature and the highest glass transition temperature of the composite resin particles is 30° C. or more, a melt viscosity of the composite resin particles at 100° C. is 4000 Pa.Math.s or more and 20000 Pa.Math.s or less, and, in a melt viscosity range of the composite resin particles of 4000 Pa.Math.s or more and 20000 Pa.Math.s or less, a slope of a logarithm of the melt viscosity of the composite resin particles relative to a temperature of the composite resin particles is −0.08 or more and −0.04 or less.

A method for producing pressure-responsive particles includes: adding an aggregating agent and a dispersion containing silica particles to a dispersion containing composite resin particles containing a styrene-based resin including a styrene compound and a vinyl monomer other than the styrene compound as polymer components and a (meth)acrylic acid ester-based resin including a (meth)acrylic acid ester compound as a polymer component to cause aggregation so as to form aggregated particles; and heating and fusing the aggregated particles to form pressure-responsive particles. The amount of the silica particles added by the dispersion containing the silica particles is 0.5 mass % or more and 10 mass % or less relative to a total mass of the composite resin particles. The mass ratio of the styrene-based resin to the (meth)acrylic acid ester-based resin in the pressure-responsive particles is from 80:20 to 20:80. A difference between the lowest glass transition temperature and the highest glass transition temperature of resins contained in the pressure-responsive particles is 30° C. or more.

A method for producing pressure-responsive particles includes: adding an aggregating agent and a dispersion containing silica particles to a dispersion containing composite resin particles containing a styrene-based resin including a styrene compound and a vinyl monomer other than the styrene compound as polymer components and a (meth)acrylic acid ester-based resin including a (meth)acrylic acid ester compound as a polymer component to cause aggregation so as to form aggregated particles; and heating and fusing the aggregated particles to form pressure-responsive particles. The amount of the silica particles added by the dispersion containing the silica particles is 0.5 mass % or more and 10 mass % or less relative to a total mass of the composite resin particles. The mass ratio of the styrene-based resin to the (meth)acrylic acid ester-based resin in the pressure-responsive particles is from 80:20 to 20:80. A difference between the lowest glass transition temperature and the highest glass transition temperature of resins contained in the pressure-responsive particles is 30° C. or more.

The present invention provides a binder composition comprising a first binder comprising by dry weight based on total dry weight of the first binder, from 5% to 98% of polymer particles, from 0.3% to 10% of a first polysaccharide, from 0.01% to 5% of a crosslinker, from 0.3% to 6% of a water-soluble metal cation, and from 0.05% to 3% of a cationic polyelectrolyte. The binder composition may further comprise a second binder comprising by dry weight based on total dry weight of the second binder, from 0.3% to 20% of the first polysaccharide, from 0.5% to 20% of a second polysaccharide. And in that case, the wet weight ratio of the first binder to the second binder is from 1:20 to 20:1. The present invention further provides a paint formulation comprising the binder composition.