The present disclosure discloses a preparation method of an ultraviolet (UV)-resistant and transparent lignin-based polyurethane (PU) elastomer. During the synthesis process, natural lignin-based polyols are directly used as an end-capping agent, isophorone diisocyanate and 2,2-dimethylolbutyric acid are used as a hard segment and polyether chain polyols are used as a soft segment, to synthesize a PU elastomer with a transparent brown appearance, excellent high elasticity and elastic recovery performance, as well as excellent mechanical properties, excellent UV resistance and repeatable processability. The lignin-based PU elastomer has a simple preparation process, and has great potential values for use in the fields such as PU elastomer film, fabric coating, and elastic fiber and biomass polymer materials.

A method of producing a polyurethane or polyisocyanurate foam is provided which involves the use of a specific combination of hydrofluoroolefin blowing agents and cell nucleators. The resulting foams have excellent long term thermal insulating performance and have reduced thickness in comparison to conventional thermal insulating boards. The rigid polyurethane and polyisocyanurate boards may be used to insulate refrigeration bodies, such as those employed in vehicles comprising refrigeration units, and cold storage containers.

A process for producing an object from a precursor comprises the steps of: I) depositing a free-radically crosslinked resin atop a carrier to obtain a ply of a construction material joined to the carrier which corresponds to a first selected cross section of the precursor; II) depositing a free-radically crosslinked resin atop a previously applied ply of the construction material to obtain a further ply of the construction material which corresponds to a further selected cross section of the precursor and which is joined to the previously applied ply; III) repeating step II) until the precursor is formed; IV) treating the precursor obtained after step III) under conditions sufficient to at least partially trimerize to isocyanurate groups NCO groups present in the free-radically crosslinked resin of the obtained precursor to obtain the object.

A flexible discontinuous process produces a series of at least two articles containing thermally insulating polyurethane foam from at least three streams (A), (B) and (C). The process involves mixing the at least three streams with different mixing ratios and injecting the mixture into cavities of the articles. A production unit can be used for performing this process.

A method of making an isocyanurate polymer is disclosed. An isocyanate including at least one of an aromatic isocyanate and an aliphatic isocyanate is provided. A trimerization catalyst including at least one of an amine catalyst, an organometallic compound, and an imidazole compound is provided. A reaction mixture that is substantially free of reactive hydrogen is formed by mixing less than about twenty percent by total weight of said reaction mixture of an epoxide with said isocyanate. The trimerization catalyst is mixed with the reaction mixture. The reaction mixture is cured to produce a polymer composition including a reaction product of two or more isocyanates.

A method for preparing rigid polyurethane (PUR) foams or rigid polyisocyanurate (PIR) foams in which method the rigid PUR or PIR foam is prepared by reacting a composition (C) comprising: at least one isocyanate-reactive component (B1) having functional groups selected from hydroxyl, amine and thiol groups; at least one isocyanate component (A1) having an average functionality of less than 2.70; and at least one blowing agent [blowing agent (BA), herein after]; with the proviso that the overall average functionality [F.sub.n,avg(A), herein after] of all isocyanate components present in the composition (C) is less than 2.70; wherein the composition (C) is characterized by an isocyanate index X, wherein the rigid PUR or PIR foams are produced by depositing the composition (C) between two gas-tight facing sheets and wherein the rigid PUR or PIR foam is characterized by a difference Δλ between the initial thermal conductivity value λ.sub.ini and the aged thermal conductivity value λ.sub.aged of said rigid PUR or PIR foam wherein: when X≤200 then Δλ<1.35; and when X>200 then Δλ<[6.49−(4.46*F.sub.n,avg(A))−(0.02348*X)+(0.492*F.sub.n,avg(A)*F.sub.n,avg(A))+(0.01343*F.sub.n,avg(A)*X)+0.3].

The present invention relates to the use of polyisocyanate compositions and trimerization catalysts for production of coatings by reaction injection molding, to the coatings obtained by the use and to correspondingly coated workpieces.

A catalyst system useful in the production of polyurethane and/or polyisocyanurate foams using hydrohaloolefin blowing agents.

Isocyanate-reactive composition that include a polyol blend, a blowing agent composition, and a catalyst. The polyol blend includes a polyether polyol having a functionality of 2 to 6 and an OH number of 20 to 50 mg KOH/g, which is present in an amount of at least 30% by weight, based on total weight of the isocyanate-reactive composition, and an aromatic polyester polyol having a functionality of 1.5 to 3 and an OH number of 150 to 450 mg KOH/g, which is present in an amount of at least 40% by weight, based on total weight of the isocyanate-reactive composition. The blowing agent composition includes water, the water being present in an amount of 1 to 20% by weight, based on total weight of the isocyanate-reactive composition and in an amount of at least 90% by weight, based on total weight of the blowing agent composition. The isocyanate-reaction composition has a green content of at least 30% by weight, based on total weight of the isocyanate-reactive composition. Polyurethane foam-forming reaction mixtures, polyurethane foams, multi-layer composite articles and methods for their production are also described.

The invention provides polyurethane and polyisocyanurate foams and methods for the preparation thereof. More particularly, the invention relates to closed-celled, polyurethane and polyisocyanurate foams and methods for their preparation. The foams are characterized by a fine uniform cell structure and little or no foam collapse. The foams are produced with a polyol premix composition which comprises a combination of a hydrohaloolefin blowing agent, a polyol, a silicone surfactant, and a precipitation-resistant metal-based catalyst used alone or in combination with an amine catalyst.