DE1704843A1 - Process for producing molded parts from foaming reaction mixtures - Google Patents

Description

Process for the production of molded parts from foaming reaction mixtures The invention relates to a method for producing molded parts from foaming Reaction mixtures in a closed form.

It is already known to produce molded parts from foaming reaction mixtures, z. B. polyurethane, polyvinyl chloride, polyethylene or the like. In closed forms produce by pouring the foamable reaction mixture into the mold and the reaction is brought to completion, if necessary by heating. When complicated designed molded parts arise difficulties, e.g. in foam hardening, Express voids, unfilled parts of the shape, etc.

Attempts have been made to overcome these difficulties e.g. by attaching To overcome sprout holes} without always completely avoiding the errors to be able to. In addition, the resulting sprouting consumes more raw material and additional labor to remove the shoots is required.

The invention is based on these disadvantages to remove. According to the invention this is achieved in that the inner walls of the Form before filling in the reaction mixture to be foamed, at least partially be lined with a layer of air-permeable soft foam. In which According to this process manufactured product, the outer area can at least partly made of flexible foam and the core made of any plastic flexible foam or other plastic foam. furthermore, the outer area can be made of flexible foam and the core is made of rigid foam.

The advantages of the method according to the invention are that Surface defects, air inclusions and cavities, which have so far been particularly common in more complicated shaped molded parts occur, are avoided. Furthermore is the structure of the molded parts evenly. Through a certain compression of the foam on the surface of the molded part, its stability and resistance to breakage are increased. Furthermore, raw material is saved, since the molded parts are produced without sprouting can. With this experience it is also possible to use e.g. a Molded part made of rigid foam this at the same time superficial or partially superficial to be connected with a correspondingly thick cushion made of soft foam, what used to be a separate operation was necessary. In this way, e.g. Armrests from Armchairs or other parts of upholstered furniture or the like. Are produced. It can including so-called bed platforms or armchair shells as well as packaging forms made of rigid foam be provided with a soft foam pad.

The inventive method consists in that the walls of the closed form lined with a layer of air-permeable soft foam and then the foaming reaction mixture is poured in.

The air-permeable soft foams can be both plastic foams e.g. polyester or polyether-polyurethane foam, as well as natural or synthetic latex foams. It is sufficient to attach the soft foam to the edge of the form, as it is caused by the pressure of the foaming reaction mixture is pressed firmly against the wall of the mold. The reaction mixture penetrates somewhat into the soft foam, creating a superficial Compression and a connection between the foam that is created and the inserted foam entry. The air in the mold is evenly distributed in the inserted foam layer distributed, whereby the resulting foam is formed with a uniform structure.

With this method it is possible, especially complicated ones Molded parts made of both hard, semi-hard and soft foam that are due to the formulation of the reaction mixture foam by itself, e.g. on the basis of Polyurethanes, polyvinyl chloride, polyethylene or the like, perfectly in closed forms to manufacture.

It is used in the manufacture of molded parts from soft foam generally not appropriate to line the entire mold wall with foam, as the entering superficial No compression of the foam is desirable in all cases. It has been found to be beneficial only the lower one or to lay out the upper wall of the mold with flexible foam. The one enclosed in the shape When the reaction mixture foams, air is then distributed in the inserted foam, and the resulting foam has a uniform structure.

The process can also be used to produce molded parts with hard Use core and soft padding. A soft foam of the desired type is used for this Thickness and elasticity inserted into the mold and proceeded as described. By the penetration of the reaction mixture into the inserted flexible foam, which subsequently occurs solidified, a firm connection is created between the hard core and the padding. This is a particularly advantageous method for making e.g. bed bases, Armchair shells or the like made of hard foam with upholstery.

Claims (3)

Claims 1. A method for producing molded parts from intumescent Reaction mixtures in a closed form, characterized in that the Inner walls of the mold before the reaction mixture to be foamed is poured in at least partially lined with a layer of air-permeable soft foam will. 2. Product according to the method according to claim 1, characterized in that that the outer area is at least partially made of flexible foam and the core of any Plastic softwood or other plastic soliaum. 3. Product according to the method according to claim 1, characterized in that that the outer area consists of soft foam and the core of hard foam.