Provided are a polycarbodiimide compound that enables an aqueous resin composition capable of forming a coating (layer) having water resistance and adhesion that can withstand use for food packaging to be obtained, an aqueous resin composition containing the polycarbodiimide compound, and a food packaging having a layer formed of the aqueous resin composition. A polycarbodiimide compound (A) represented by formula (1) below,

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wherein R.sup.1 represents a residue obtained by removing a functional group capable of reacting with isocyanate from a hydrophilic compound having the functional group capable of reacting with isocyanate, R.sup.2 represents a divalent residue obtained by removing an isocyanate group from an aliphatic diisocyanate compound, and R.sup.3 represents a divalent residue obtained by removing a hydroxyl group from a glycol compound having 2 or 3 carbon atoms; X represents a group that is formed by reaction between the hydrophilic compound and the aliphatic diisocyanate compound; n1 represents a number of 1 to 10, n2 represents a number of 1 to 10, and p represents a number of 2 to 4; and a plurality of R.sup.1 and R.sup.2 each may be the same or different.

Described herein is a method for the preparation of a rigid polyisocyanate based foam, including mixing (a) polyisocyanate, (b) at least one compound having at least two hydrogen atoms reactive towards isocyanates, (c) optionally flame retardant, (d) blowing agent, (e) catalyst and (f) optionally further additives, to form a reaction mixture and reacting the reaction mixture to obtain the polyurethane based rigid foam where the compound reactive towards isocyanates (b) includes an aromatic polyetherpolyol (b2) and at least one compound selected from the group consisting of an aromatic polyesterpolyol (b1) and a polyetherpolyol (b3) different from polyether (b2). Also described herein is a rigid polyisocyanate based foam obtained from such a method and a polyol component for the production of a polyisocyanate based foam.

A modified polycarbodiimide compound which is obtained by modifying at least some of carbodiimide groups in a polycarbodiimide derived from a diisocyanate compound, said polycarbodiimide having a terminal blocked with a hydrophilic compound, with an aromatic heterocyclic compound such as 3,5-dimethylpyrazole having endocyclic secondary amine nitrogen has a potential for a cuing agent, and exhibits the activity of the carbodiimide groups by being unblocked at relatively low temperatures.

This invention relates to rigid polyurethane foams which are co-blown with a mixture of a hydrocarbon blowing agent and a halogenated olefin blowing agent. This invention also relates to a process for preparing these rigid polyurethane foams, and to an isocyanate-reactive component containing a polyol blend and the mixture of blowing agents. Phase stable isocyanate-reactive blends are also described.

The invention relates to polymerizable compositions that are suitable for preparing polyisocyanurate-based plastics and have an extended worklife as compared to the compositions conventionally used for this purpose.

Polyurethane-polyisocyanurate foams are prepared using a polyether polyol made from an alkylene oxide mixture that contains a specified proportion of ethylene oxide. The selection of proper polyol equivalent weight and ethylene oxide content leads to the production of foams having a useful combination of properties.

A process is described for producing PU foams, especially rigid PU foams, based on foamable reaction mixtures containing polyisocyanates, compounds having reactive hydrogen atoms, blowing agents, foam stabilizers, and possibly further additives, wherein polymer particles are additionally used, the average particle size of the polymer particles being <100 μm, preferably <70 μm, especially 5 to 50 μm.

A polyol pre-mix containing at least one halogenated hydroolefin blowing agent and having improved shelf life stability is provided, wherein each polyol combined with the halogenated hydroolefin blowing agent has an apparent pH of between 3 and 11.4. Controlling the apparent pH of the polyol(s) enables the polyol pre-mix to be stored for extended periods of time and then used in combination with organic polyisocyanate to produce foam formulations having gel times and tack free times not significantly different from those exhibited when freshly prepared polyol pre-mix is used.

The present invention provides compositions having a phase transfer trimer catalyst and methods to produce polyisocyanurate/polyurethane foam using such compositions.

A method for preparing polyisocyanurate and polyurethane foams by the use of a liquid siloxane nucleating additive, and a foam-forming composition for preparing foams with improved thermal insulation performance, comprising an isocyanate component, an isocyanate-reactive component, a blowing agent, and a liquid siloxane nucleating additive.