摘要:
This invention relates to biodegradable starch-based pellets which foamable by irradiation, which are particularly suitable for the manufacture of foam articles, characterised in that they have a porous structure with a low porous external skin. This invention also relates to foam articles obtained from these.
摘要:
Foamed products with free-rise densities between 0.05 and 0.22 are obtained by reacting at least one polyol with at least one isocyanate-prepolymer, in the presence of an amount of expandable microspheres within the range of 1.0% to 30% by weight on the weight of said polyol and an amount of expanding agent which is from 0.5 to 0.1 times the amount of microspheres, and carrying out the polymer expansion step at a temperature which is sufficient to cause the expansion of the microspheres.
摘要:
It is found that a polyurethane foam having significantly reduced or negligible amine emissions can be obtained by reacting a polyol with a polyisocyanate in the presence of a blowing agent being a carbamate, obtained from contacting carbon dioxide with an amine or alkanolamine, and further in the presence of a non-fugitive amine catalyst. A process is disclosed which has particular utility for the preparation of integral skinned foam, such as automotive steering wheels, exhibiting attractive physical performance and low volatile amine emissions.
摘要:
The present invention provides a method for the semi-continuous production of microcellular foam articles. In a preferred embodiment, a roll of polymer sheet is provided with a gas channelling means interleaved between the layers of polymer. The roll is exposed to a non-reacting gas at elevated pressure for a period of time sufficient to achieve a desired concentration of gas within the polymer. The saturated polymer sheet is then separated from the gas channelling means and bubble nucleation and growth is initiated by heating the polymer sheet. After foaming, bubble nucleation and growth is quenched by cooling the foamed polymer sheet.
摘要:
The present invention relates, at least in part, to integral skin foam premix compositions, foams, and method of producing such foams. In certain aspects, the premix is storage stable and includes a hydrohaloolefin blowing agent, one or more polyols, one or more surfactants, and a catalyst.
摘要:
The invention generally relates to a process for the preparation of water-absorbent polymer particles, comprising the process steps of (i) preparing an aqueous monomer solution comprising at least one partially neutralized, monoethylenically unsaturated monomer bearing carboxylic acid groups (α1) and at least one crosslinker (α3); (ii) optionally adding fine particles of a water-absorbent polymer; (iii) adding a polymerization initiator or a at least one component of a polymerization initiator system that comprises two or more components to the aqueous monomer solution; (iv) optionally decreasing the oxygen content of the aqueous monomer solution; (v) charging the aqueous monomer solution onto a belt of a polymerization belt reactor; (vi) polymerizing the monomers, thereby obtaining a polymer gel; (vii) discharging the polymer gel from the belt and optionally comminuting the polymer gel; (viii) drying the optionally comminuted polymer gel; (ix) grinding the dried polymer gel thereby obtaining water-absorbent polymer particles; (x) sizing the grinded water-absorbent polymer particles; and (xi) optionally treating the surface of the grinded and sized water-absorbent polymer particles; wherein one of the process steps (i) to (vi) further comprises, adding a blowing agent in an amount in a range from 500 to 4000 ppm, based on the total weight of the monoethylenically unsaturated monomers; and wherein the polymer gel obtained in step (vi) has a water content in the range from 40 to 60 wt.-%, based on the total weight of the polymer gel; and wherein during the drying step (viii) water is removed from the polymer gel in a rate in the range from 120 to 240 kg/minute and the obtained dried polymer gel has a water content in the range from 3 to 7 wt.-%, based on the total weight of the dried polymer gel.
摘要:
The instant application discloses, among other things, ways to manufacture reduced density thermoplastics. A rapid foaming process which may create a polymer product by saturating thermoplastic sheet or preforms, heating, and then forming into final shape, is described. The polymer product may include an integral solid skin. This method may be utilized with any thermoplastic. The material handling, saturation methods, and end products are also described.
摘要:
The instant application discloses, among other things, ways to manufacture reduced density thermoplastics. A rapid foaming process which may create a polymer product by saturating thermoplastic sheet or preforms, heating, and then forming into final shape, is described. The polymer product may include an integral solid skin. This method may be utilized with any thermoplastic. The material handling, saturation methods, and end products are also described.