The present invention relates to a process for preparing at least one blocked polyisocyanate, comprising the following steps: (A) reacting at least one polyisocyanate with at least one thermally cleavable blocking agent to obtain at least one partially blocked polyisocyanate, (B) reacting the at least one partially blocked polyisocyanate from step (A) with at least one non-ionic hydrophilizing agent to obtain an intermediate product, and (C) reacting the intermediate product obtained in step (B) with at least one thermally cleavable blocking agent to obtain the at least one blocked polyisocyanate. The invention further relates to the use of the blocked polyisocyanate for producing coating agents, adhesives, sealants or elastomers, to corresponding coating agents, adhesives, sealants or elastomers, and to substrates that are provided with coatings obtained using the at least one blocked polyisocyanate according to the invention.

This invention provides a polymer thick film electrically conductive paste composition, comprising conductive metal powder, a resin blend of polyol and phenoxy resin, blocked aliphatic polyisocyanate and one or more polar, aprotic solvents. In one embodiment the paste composition is used to form electrically conductive adhesive. In another embodiment the paste composition is used to form an electrically conductive polymer thick film.

The present invention relates to a process for preparing at least one blocked polyisocyanate, comprising the following steps: (A) reacting at least one polyisocyanate with at least one thermally cleavable blocking agent selected from the group consisting of primary, monofunctional alcohols and mixtures thereof to obtain at least one partially blocked polyisocyanate, (B) reacting the at least one partially blocked polyisocyanate from step (A) with at least one non-ionic hydrophilizing agent to obtain an intermediate product, and (C) reacting the intermediate product obtained in step (C) with at least one thermally cleavable blocking agent selected from the group consisting of primary, monofunctional alcohols and mixtures thereof, to obtain the at least one blocked polyisocyanate. The invention further relates to a correspondingly obtained blocked polyisocyanate, to the use of the blocked polyisocyanate for producing coating agents, adhesives, sealants or elastomers, to corresponding coating agents, adhesives, sealants or elastomers, and to substrates that are provided with coatings obtained using the at least one blocked polyisocyanate according to the invention.

This blocked polyisocyanate composition contains a block polyisocyanate derived from one or more diisocyanates, an active hydrogen compound, and a blocking agent containing a malonic acid ester. The active hydrogen compound has a number-average molecular weight of 60 to 5,000 and an average of 1.6 to 2.4 functional groups.

The invention provides a laminated polyester film that is highly transparent, is resistant to blocking, and has excellent adhesion to a hardcoat layer and UV ink. The laminated polyester film contains a polyester film substrate and a coating layer on at least one surface of the polyester film substrate, wherein the coating layer is formed by curing a composition containing a urethane resin with a polycarbonate structure and a branched structure, a crosslinking agent, and a polyester resin.

The invention provides a laminated polyester film that is highly transparent, is resistant to blocking, and has excellent adhesion to a hardcoat layer and UV ink. The laminated polyester film contains a polyester film substrate and a coating layer on at least one surface of the polyester film substrate, wherein the coating layer is formed by curing a composition containing a urethane resin with a polycarbonate structure and a branched structure, a crosslinking agent, and a polyester resin.

The present invention provides a blocked polyisocyanate composition comprising a blocked polyisocyanate formed through blocking at least a part of isocyanate groups possessed by a polyisocyanate derived from one or two or more diisocyanates selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate with an active methylene-based compound comprising a malonic acid diester, wherein a specific molar ratio calculated from contents (mol %) of isocyanurate groups, iminooxadiazinedione groups, uretdione groups, and allophanate groups is 0.05 or more and 0.60 or less.

A blocked isocyanate has an isocyanate group of a polyisocyanate compound blocked with one or more blocking agents including a first blocking agent, which is represented by general formula (1). At least some of the first blocking agent has been neutralized with acid.

##STR00001##

(wherein R.sup.1 to R.sup.5 each represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms; R.sup.1 and R.sup.3 may be bonded to each other to form a heterocycle, R.sup.4 and R.sup.1 may be bonded to each other to form a heterocycle, and R.sup.5 and R.sup.3 may be bonded to each other to form a heterocycle).

An alternative polyurethane composition is provided which comprises a reaction product of an azidated polyol and a poly(alkynyl carbamate) prepolymer, wherein reaction occurs at a temperature of from 20° C. to 200° C., optionally in the presence of a Cu.sup.I-containing catalyst and wherein the poly(alkynyl carbamate) prepolymer comprises a reaction product of a polyisocyanate, an alkynol, and a glycol ether, wherein from 1 mol % to 33 mol % of isocyanate groups are reacted with glycol ether and the remaining isocyanate groups are reacted with the alkynol. The inclusion of glycol ethers into the polyisocyanate chain of the poly(alkynyl carbamate) prepolymer at a level of from 1 mol % to 33 mol %, is efficient in reducing the viscosity of the composition without compromising its performance in coatings, adhesives, sealants, films, elastomers, castings, foams, and composites made with the inventive alternative polyurethane compositions.

The blocked isocyanate is a blocked isocyanate containing a latent isocyanate group, which is an isocyanate group blocked with a blocking agent, wherein the blocked isocyanate includes a first latent isocyanate group that is an isocyanate group blocked with a first blocking agent and a second latent isocyanate group that is an isocyanate group blocked with a second blocking agent; and the first blocking agent is represented by general formula (1) below, and has a higher catalysis activity that activates the isocyanate group than that of the second blocking agent. ##STR00001##
(where R1 to R3 represent a hydrocarbon group having 1 to 12 carbon atoms or a hydrogen atom, and at least one of R1 to R3 represents a hydrogen atom, and R1 and R3 may be bonded to each other to form a heterocycle. R4 represents a hydrocarbon group having 1 to 12 carbon atoms, a hydrogen atom, or an atomic group represented by —NR.sup.5R.sup.6 (R5 and R6 represent a hydrocarbon group having 1 to 12 carbon atoms, and R5 and R1 may be bonded to each other to form a heterocycle and R6 and R3 may be bonded to each other to form a heterocycle).