摘要:
An apparatus for mixing and molding a chemically foamable reaction mixture is comprised of a mold with a mixing chamber which has its outlet aperture in a wall of the mold and a displacement piston mounted in the opposite wall. An ejector piston is displaceable within the mix chamber and may be so channelled as to serve as a control piston. This ejector piston is displaceable from a position wherein the injection apertures lie between it and the mold cavity to a position wherein its end surface is flush with the mold wall. The displacement piston is so mounted that it may extend across the mold cavity and intrude into the outlet aperture of the mixing chamber. This displacement piston has a diameter smaller than the diameter of those portions of the mixing chamber into which it protrudes so that when this piston is within the mixing chamber an annular cavity is formed between it and the side walls of the mixing chamber. It is withdrawable to a position flush with the mold wall it protrudes through. This piston may comprise a hollow sleeve and a core which together form a cavity when the sleeve is disposed in the mixing chamber. This piston may be mounted in a mold wall insert which can be moved toward the opposite mold wall to locally decrease the mold cavity width. The mix chamber and displacement piston may also be mounted in opposite walls of a sprue system which communicates with a mold cavity or mold cavities.
摘要:
This invention relates to an apparatus for dosing and mixing at least two fluid reactants consisting of a dosing unit; a mixing head and conduits connecting the dosing unit and mixing head; characterized in that the housing of the dosing unit and the mixing head together form a rigid block with the conduits connecting the dosing cylinder with the mixing chamber in the form of channels inside the block.
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 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:
The present invention is directed to a process for the production of a molded article having a compact surface layer and a gross density above 900 kg/m.sup.3 via the reaction injection molding technique, comprising introducing a reaction mixture into a closed mold, said reaction mixture comprising:(a) a polyisocyanate component consisting of at least one polyisocyanate in which all the isocyanate groups are aromatically bound,(b) compounds having molecular weights of from 400 to 12,000 and having at least two isocyanate reactive hydrogen atoms,(c) water, in a quantity of at least 0.15 mol per mol of isocyanate groups of component (a), and(d) optionally compounds having molecular weights of from 60 to 399 and having at least two isocyanate reactive hydrogen atoms,wherein the isocyanate index, based on all the reactants taking part in the reaction is from 70 to 125, and wherein a pressure of above 40 bar is maintained in the reaction mixture during the reaction so that the carbon dioxide formed in the course of the reaction remains completely or predominantly in solution in the reaction mixture and in the molded article produced.
摘要翻译:本发明涉及通过反应注射成型技术生产具有紧密表面层和总密度高于900kg / m 3的模塑制品的方法,包括将反应混合物引入封闭模具中,所述反应混合物包含 (a)由至少一种多异氰酸酯组成的多异氰酸酯组分,其中所有异氰酸酯基团都被芳族结合,(b)分子量为400至12,000并具有至少两个异氰酸酯反应性氢原子的化合物,(c)水, 每摩尔组分(a)的异氰酸酯基团至少为0.15摩尔的量,和(d)任选分子量为60至399的具有至少两个异氰酸酯反应性氢原子的化合物,其中异氰酸酯指数基于 参与反应的所有反应物均为70〜125,在反应中反应混合物中保持40巴以上的压力,使二氧化碳 在反应过程中形成的反应完全或主要存在于反应混合物和所制备的模制品中的溶液中。
摘要:
A first reaction mixture, prepared from (a) aromatic isocyanates with isocyanate contents of from 5 to 50%, and (b) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component "a" to component "b" of 0.8:1 to 5:1, from 0.1 to 20% of a blowing agent and, optionally, other known additives, is introduced into a closed mold with a rigid cavity. After this mixture has become resistant to permeation, but is still compressible, a second reaction mixture, prepared from (c) aliphatic and/or cycloaliphatic polyisocyanates having isocyanate contents of from 5 to 50% and (d) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component "c" to component "d" of from 0.8:1 to 5:1, an internal mold release agent and optionally blowing agents and other additives, is introduced into the mold, such that the second mixture surrounds the first mixture and compresses it. A third, optional, reaction mixture, the same as or different from the second mixture, may also be employed in a manner similar to the introduction of the second mixture. The final composite plastic part releases smoothly from the mold and evidences good lightfast and colorfast properties.
摘要:
The present invention relates to a process and a device for the production of a composite part by the sequential introduction of several fillings (consisting of at least one free-flowing reaction mixture, of which at least one forms a foamed material) into the hollow space of the mold of a closed form tool. A mixing device is attached to form tool. The mixer comprises injector nozzles for the reaction components pointing into a mixing chamber and an ejector piston for the cleaning of the mixer chamber. The ejector piston may be slid forward right up to the outlet orifice of the mixing chamber.
摘要:
A pneumatic tire comprising an encircling tread and two side members, wherein each side member comprises a side wall having a bead ring and part of the tread backing, characterized in that said tread backing has the following features:(a) the tread backing is formed as a ring which extends to the center of the tire and is intimately joined to the side wall on the other side;(b) bands whose length is substantially equal to the width of said ring are fixed on the circumference of said ring in the center of the tread;(c) the width of said bands is approximately equal to the distance between said bands;(d) there are recesses in the part of said ring facing the tread, into which said bands of the other side fit during assembly, so that said tread backing has a substantially flush surface after assembly; and(e) there are beads on the end of said bands for clamping in the tread.
摘要:
The invention is related to a method of assembling a segmented tire mold core from core segments inside a tire mold, a method of splitting up and removing a segmented tire mold core from a tire mold and an apparatus comprising a tool which determines the outer contour of a tire and a segmented tire mold core which determines the internal contour of a tire, as well as the associated charging, conveying and control devices.