The disclosure relates to adhesive compositions, including non-crosslinked resins and crosslinked/cured adhesives joining substrates, as well as related methods for making the compositions and articles. Compared to a conventional phenol (P) and formaldehyde (F) resin, the disclosed methods and compositions use lignin (L), formaldehyde (F), and optionally higher aldehydes (A) as corresponding replacements to provide an analog to a conventional PF resin with biobased reactants. Due to the differing reactivity of the LF components compared to the PF components, the initial condensation reaction between ortho-reactive sites in the lignin and the aldehyde is controlled to prevent gelation of the aqueous reaction mixture while reacting substantially all of the LF reactants to provide a non-crosslinked resin reaction product. The resin reaction product can then be cured at high temperature/high pressure conditions to provide a crosslinked adhesive, for example joining two substrates.

Methods for making composite products are provided. In at least one specific embodiment, the method can include combining a plurality of lignocellulose substrates and one or more free radical precursors to produce a mixture of the lignocellulose substrates and the one or more free radical precursors. The method can also include maintaining the mixture at a temperature less than 60 C. for at least 10 minutes while retaining at least 11 wt % of the one or more free radical precursors charged to the mixture. The method can then include heating the mixture comprising at least 11 wt % of the one or more free radical precursors charged to the mixture to a temperature of at least 60 C. to about 300 C. to produce a composite product. The composite product can have a density less than 1 g/cm.sup.3 and an internal bond strength of at least 0.35 MPa.

The present invention relates to an adhesive formulation comprising lignin, suitable for use in the manufacture of for example wood products. The lignin is provided in the form of a solution or dispersion or in dry solid form, such as in the form of a powder. The adhesive formulation also comprises phenol-formaldehyde (PF) resin and/or lignin-phenol-formaldehyde (LPF) resin. The adhesive formulation may also comprise extenders, hardeners, fillers and other additives, to achieve an adhesive formulation useful in the manufacture of for example wood products, such as plywood and laminated veneer lumber (LVL). The adhesive formulation can also be used in the manufacture of laminates and oriented strand boards.

This disclosure includes adhesive compositions comprising lignin, as well as methods of making such adhesive compositions, methods of making glyoxalated lignin or glyoxalating lignin-fiber mixtures, particularly glyoxalated kraft lignin, and methods of making lignocellulosic composite products including the present adhesive compositions.

This disclosure includes adhesive compositions comprising lignin, as well as methods of making such adhesive compositions, methods of making glyoxalated lignin or glyoxalating lignin-fiber mixtures, particularly glyoxalated kraft lignin, and methods of making lignocellulosic composite products including the present adhesive compositions.

The present invention relates to a method for increasing the reactivity of lignin, wherein the method comprises the following steps: a) forming, under heating at a temperature of 71-94 C., an aqueous dispersion comprising alkali and lignin, wherein the alkali comprises a hydroxide of an alkali metal; and b) heating the dispersion formed in step a) at a temperature of 50-95 C. for producing alkalated lignin.

The present invention relates to a method for increasing the reactivity of lignin, wherein the method comprises the following steps: a) forming, under heating at a temperature of 30-70 C., an aqueous dispersion comprising alkali and lignin, wherein the alkali comprises a hydroxide of an alkali metal; and b) heating the dispersion formed in step a) at a temperature of 50-95 C. for producing alkalated lignin.

The present describes wood adhesives reinforced with cellulose nanocrystals (CNC), in liquid and powder forms in which resin system are a phenol-formaldehyde polymer and/or lignin-phenol-formaldehyde polymer and polymeric methylene diphenyl diisocyanate (pMDI), and a method of making this polymer in liquid and powder from and the composite products that can be produced therefrom.

A method for producing a binder composition without using a compound selected from the class of phenols, is disclosed. The method comprises: (i) heating an aqueous composition comprising lignin and lignin oligomer in the presence of a catalyst at a temperature of 50-95? ? C. for 0.25-5 hours; (ii) mixing a cross-linking agent with the aqueous composition from (i) and heating the same at a temperature of 60-95? C. for polymerizing lignin, lignin oligomers, and cross-linking agent until a binder composition with a predetermined viscosity value is formed; wherein the molar ratio of crosslinking agent to lignin and lignin oligomer is 0.5-1.8.

The present invention relates to a method for treating lignin, wherein the method comprises the following steps: a) dissolving lignin into an aqueous composition, which contains a compound selected from the class of phenols and alkali, while keeping the temperature of the composition at 40-85? C., wherein the alkali comprises a hydroxide of an alkali metal; and b) heating the composition at a temperature, which is higher than the temperature of the composition in step a), with the proviso that the temperature of the composition does not exceed 100? C., while keeping the pH of the composition at a pH value of 6-14.