摘要:
A process for molding foam products substantially free from flaws caused by air bubbles in the foamable reaction mixture wherein a foamable reaction mixture having a viscosity .eta. in cP between 100 cP and 2500 cP is introduced into a mold cavity through an opening in the mold wall and against the wall of the cavity opposite the opening of a mold in which the thickness of the cavity and the thickness s of the resulting molded product adjacent to the opening at the time the mixture is introduced into the cavity is maintained at 0.5 mm to 15 mm under conditions whereby the radial distribution rate w.sub.radial in m/sec., .eta. in cP and s combine to satisfy the relation ##EQU1##
摘要:
Apparatus to practice the method of forming foam molded articles without the defects caused by incompletely mixed reactants in the mold cavity is provided. A mixing chamber bounded by a sidewall portion having injection apertures, an outlet aperture which communicates with the mold cavity and a first ejector piston displaceable within the bore of the mixing chamber is provided. Opposite said outlet aperture is a second ejector piston which is retracted at the start of the mold filling operation to provide a receiving chamber in the mold wall. As the mold filling proceeds, this piston is displaced towards the mold cavity until its end surface forms a planar surface with the mold wall. Optionally, this piston may be displaced into the mold cavity to eject the molded article.
摘要:
A foam cushion with a covering of an elastic textile sheet structure is produced in a vacuum deep-draw mould by holding the sheet structure down during the suction cycle with a hold-down plate, but allowing it to slip through locally.
摘要:
Polyol mixtures containing a mixture of internal mold release agents which are storage stable are made up of (a) from about 55 to about 95% by weight of a polyol mixture of (1) 30-70% by weight of at least one polyol with an OH value of more than 700 and (2) from about 30 to about 70% by weight of at least one polyol with an OH value of 700 or less than 700 and (b) from about 5 to about 45% by weight of a mixture of internal mold release agents made up of (1) from about 60 to about 95% by weight of at least one salt-like release agent and (2) from about 5 to about 40% by weight of at least one non-salt-like release agent containing an amide NH function or a urethane NH function. Known auxiliaries and additives may optionally be included. These polyol mixtures are useful in the production of rigid, semirigid and flexible polyurethane materials, particularly molded polyurethanes.
摘要:
The present invention is directed to a tire comprising a three-dimensional wound reinforcement formed from a continuous sheathed filament running diagonally over the region upon which the tread is located and alternating from one tire foot to the other, said filament (i) crossing back and forth over said region, (ii) running into the tire foot tangentially, (iii) running for a relatively long distance in the tire foot, and (iv) crossing over itself over the entire tire shape, said reinforcement resisting forces radially and circumferentially, and an elastomeric material surrounding said reinforcement and to a method of manufacture thereof.
摘要:
This invention relates to a pneumatic tire comprising a tread surface and two separate side parts of an elastomeric synthetic resin and optionally reinforcing elements, wherein the side part not only forms the side wall of the tire but extends from the rim wire to the mid-line of the tire and therefore also forms the foundation for the tread surface on one side, and to a process for the manufacture of such pneumatic tires.
摘要:
A process is provided for introducing mixed foamable reactants to a mold. The process involves introducing the reactants into a mixing chamber through injection apertures in its side wall portion. The mixing chamber has an outlet aperture communicating with the cavity of the mold. Prior to introducing the reactants into the mixing chamber, a displacement piston having a smaller cross-section than the mixing chamber is inserted into the outlet aperture of the mixing chamber so that the injection apertures communicate with the mold cavity by means of a generally annular passage.
摘要:
Composite sections of differing cross sectional shapes and sizes can be produced from individual profiles economically by a method in which separate guides are associated with each profile. The guides can be adjusted transversely and vertically. The guides act through guide surfaces which bear upon the top, bottom and both sides of each profile.
摘要:
Sandwich elements in the form of slabs, shells and the like, consisting of facings and a rigid polyurethane foam core can be joined together in an airtight and watertight manner when they are provided with edge profiles which are cast from casting materials forming flexible polyurethane foam and which have a groove and a tongue.
摘要:
The present invention is directed to a process for the production of light-resistant, optionally foamed elastomeric molded polyurethanes by reacting(a) organic polyisocyanates which are either mixtures of isophorone diisocyanate with polyisocyanates containing isocyanurate groups and based on 1,6-diisocyanatohexane or mixtures of IPDI with polyisocyanates containing isocyanurate groups and based on 1,6-diisocyanato-hexane and IPDI with organic compounds containing isocyanate-reactive groups in the presence of catalysts, wherein the components are reacted together inside closed molds in an isocyanate index of about 70 to 130.The present invention is additionally directed to the elastomeric polyurethanes prepared by this process.