Densified hygroscopic materials and products made thereof

A method for producing a laminated structure comprising the steps of:

• a) densifying a layer of hygroscopic material comprising a natural hygroscopic material or wood, the densifying comprising:
• i) providing the hygroscopic material to be densified;
• ii) pre-conditioning of the hygroscopic material by adjusting the moisture content of the hygroscopic material to a value within a predefined moisture range, if required;
• iii) simultaneously heating and pressing the hygroscopic material under predefined temperature and pressure conditions, wherein the moisture content of the hygroscopic material is kept constant;
• and
• iv) obtaining a densified material,
• wherein:
• the layer of the hygroscopic material is densified in said method step of densifying a hygroscopic material, and afterwards laminated with at least one further layer, wherein the at least one further layer comprising at least one of:
• (i) another layer of hygroscopic material that was densified according to said method step of densifying a hygroscopic material;
• and/or;
• (ii) plant-based material, animal-based material and/or wood-based material comprising paper, plant and/or wood fibers, wood-chips, wood flour, cellulose, starch, lignin, wood bark, wood extractives, algae, chitin-based materials, chitosan-based materials, native wood, protein, coal, char, carbon black and/or active coal;
• and/or;
• (iii) metals and/or metal alloys comprising Aluminum, Steel, Copper, Silver, Gold, and/or Titanium;
• and/or;
• (iv) polymeric materials comprising synthetic polymers and/or biopolymers, e.g. PLA, PET, PP, PE, PVC and/or proteins;
• and/or;
• and
• (v) inorganic materials selected from ceramics, glass, stone, clay, metal-organic frameworks, zeolites, coal, char, carbon black and/or active coal;
• or other porous or non-porous inorganic materials,
• wherein the laminated structure is produced such that the laminated structure comprises:
• a) a backside made of a layer of a densified or non-densified wood veneer;
• b) a frontside made of a layer of a densified or non-densified wood veneer;
• and
• c) an integrated circuit, a memory device, a tracking device, a sensing device, an antenna and/or an electromagnetic coil,
• wherein the layers are laminated and at least one of the layers of wood veneer is made of densified wood veneer, and
• wherein the densification step comprises the following sub-steps:
• iii1) the hygroscopic material is pre-heated to a first temperature at a first pressure and kept for a predefined first dwell time, wherein, the first pressure is equal to ambient pressure;
• iii2) while keeping the first temperature, the pressure is raised to a second pressure, at a constant rate of pressure increase, and kept for a predefined second dwell time;
• iii3) while keeping the second pressure, the temperature is increased to a second temperature, at a constant rate of temperature increase, and kept for a predefined third dwell time;
• iii4) reducing the temperature to room temperature;
• and
• iii5) reducing the pressure to ambient pressure.