DE2114446A1 - Foam with dense skin - on both sides produced by joining two foam layers externally cooled - Google Patents

Abstract

A method for making a foam plastic witha dense skin on one side consists of foaming the plastic from one side to a temp. >m.pt., while keeping the other face at m.pt., as in the parent patent. This is now improved to produce a foam with a dense skin on both sides as follows: two layers, >=1 of which can be foamed, are brought together at their formed sides, while the other two external faces are kept at a temp. below the foaming temp. pref. m.pt.

Description

Process for the production of foamed textile materials.

2. Addition to DBP ... (patent application P 2000 757.8) Das Deutsch Federal patent (patent application P 20 00 737.8) relates to a method for manufacturing of foamed plastics by mixing the plastic with blowing agents, if necessary Crosslinking agents and other additives and subsequent heating that thereby is characterized in that to create a unilaterally dense surface one The side is heated to a temperature T1, which is above the melting range T5 of the plastic lies, foams and, if necessary, networked, while the other side is on maintains a temperature T2 which is below T1.

According to a further embodiment of the invention, the procedure is that mn a wide, .tuf a temperature T1, which is above the melting range Ts des Plastic lies while the other side is kept at a temperature T2 lies below the melting range T5 of the plastic.

It is also possible that one page on one.

Heated temperature? 1, which is above the melting range of the plastic while the other side is kept at a temperature T2 which is equal to or The melting range T8 of the plastic is roughly the same.

However, the other side is preferably cooled.

Before heating and foaming, the plastic containing propellant can be used can be shaped into a molding, sheet, film, sheet or profile. But it is just as well possible, the plastic in the form of a fine or coarse-grained powder to be used in thin or thick layers.

After further development of the invention, one can click on or on Both sides of the plastic form a shell structure before heating and foaming raise.

It is also possible between two or more layers of plastic and / or moldings before heating and foaming one or more sheet-like structures bring in.

With the invention it is possible to use discontinuous or continuous wise to produce foams with a compact surface that is compressed on one side.

The solid surface is characterized by its smoothness and shine.

Due to the type and intensity of cooling, the density can be hard Top layer can be changed. The necessary to carry out the procedure Molds and apparatus are simple in nature and easy to use.

It has now been found that the same process can be used to produce foams that have a hard and grainy surface on both sides.

One proceeds in such a way that one has two layers of the plastic of those At least one is foamable, during or after foaming the foamable Layer or the two foamable layers with their foam to be foamed or foamed Side merges and connects and the two outer sides at one temperature 2, which is below the temperature required for frothing! 1.

It is advisable to keep the two outer sides at the same temperature T2 which is below the Schmehlzberelches T of the plastic used.

This can be done in a simple way by cooling the two air-conditioning sides can be achieved.

In this embodiment of the invention, too, as in the case of the main patent D3P .... (patent application P 20 00 737.8) between two layers of the plastic one reinforcing insert can be introduced.

The two layers can also consist of different plastics. For example, one plastic made of high pressure polyethylene and the other plastic consist of polypropylene. If only one layer of the plastic is pucked, i.e. contains only one layer of the plastic propellant, you can also use two different ones Plastics are applied. For example, the plastic to be foamed made of polyethylene, the layer of non-foamable plastics made of polyvinyl chloride or polyamide.

Furthermore, you can use the plastic of one layer or both layers during or after puffing up, one or both layers of an already pre-crosslinked plastic. Ptr the networking are common Crosslinking agents such as organic.

Peroxides, useful. Radiation crosslinking is also possible.

For example, plastics pre-crosslinked with radiation can be used will.

Deformed as in the main patent DBP .... (patent application P 20 00 737.8) it is advantageous to remove the plastic of one or both layers before heating and foaming into a molding such as a film, a plate, a tape and the same.

Some examples of the invention are shown in the drawings and are described in more detail below. They show: FIG. 1 a schematic representation a device for the continuous production of the plastic product according to the invention, FIG. 2 shows the same device shown in FIG. 1 using IR radiators.

In the figures, 1 and 1 'denote the rolled-up layers of the plastic in the form of foils or tapes, 2 and 2t pulleys, 3 and 3 'foam rollers, or IR emitter 4 the housing, -5 and 5 'the foamed foils or tapes on one side, 6 and 6 'press rollers 7 and 7' straightening rollers, 8 a deflection roller, i and 9 'feed for the cooling air or nebulization nozzles for cooling water, 10 and 10 'outlet for cooling air -or fogging water, -11 the plate cutter for the finished plastic product, 12 and 13 a reinforcement insert.

Example 1 Aua a mixture consisting of 100 parts by weight of high-pressure polyethylene (Density 0.92 g / cm³; crystallinity 75%; softening point 120 ° C) 2.0 "azodicarbonamide 0.5 "zinc oxide strips with a thickness of 1 mm are extruded and auigorolled. Two such rolled-up moldings 1. and 1 'are shown in FIG Deflection rollers 2 and 2 'unrolled and onto the two steam-heated foaming rollers 3 and 3 ', which are surrounded by a housing 4, out. Both rollers had one Diameter of 120 cm and were heated to a temperature of 310 ° C. The den Foaming rollers 3, 3 'facing sides of the plastic foamed on one side to the two structures 5 and 5 '. The outsides are through at 9 and 9 ' air introduced and discharged at 10 and 10 'is cooled. The two structures 5 and 5 'are jointly guided over press rollers 6 and 6' and with those facing each other Foam sides connected and came from here as a uniform structure over the two straightening rollers 7 and 7 'and via the pulley 8 as a finished plastic product 12 to cutting device 11.

Example 2 The following mixture is prepared: 100 parts by weight of high-pressure polyethylene (Density 0.92 vom3, crystallinity 75%, softening point 12000 0.8 n azodicarbonamite 0.5 "zinc oxide 0.5" dicumyl peroxide.

This mixture is made into a tape with a conventional extruder processed with a thickness of 1 mm and rolled up (1).

Furthermore, a mixture of 100.0 parts by weight of polypropylene 0.8 " Azodicarbonamide 0.5 "zinc oxide 0.5" dicumyl peroxide also to a tape with 0.5 mm thick extruded (1 ').

The two strips 1 and 1 rolled up according to FIG. 2 are placed in the oven introduced and led past two JR emitters. The surface temperature of the The plastic sides to be peeled are between 175-185 ° C. At the same time becomes Reinforcement over roll 13 a wide-meshed glass fiber fleece and with the tape 1 'together over the cropping roller 3'. The fleece can of course also be guided over the foaming roller 3.

After the one-sided foaming to form the structures 5 and 5 ', these are firmly connected together via 6 and 6 'and via 7 and 7', so that a uniform, Reinforced plastic product 12 is produced, which can be cut through 11.

Example 3 The mixture given in Example 1 becomes ribbons extruded with a thickness of 2 mm and rolled up to 1.-From the same mixture, However, without the addition of azodicarbonamide as a propellant, tapes are also made extruded with a thickness of 1 mm and rolled up to 1 '. The rolled up moldings 1 and 1 'are rolled over the pulleys 2 and 2' according to Fig. 1 and onto the two foaming rollers 3 and 3 'heated by steam. The SehOuswalse 3 will Maintained at a temperature of 310 C, the roller 3 'at a temperature of 12,000. The side of the plastic molding facing the foaming roller 3 foams into the structure 5 on, while the side facing the roller 3 'of the propellant-free Molding becomes plastic. Both structures 5 and 5 'are given as in Example 1, guided over the press rollers 6 and 6 'and connected with their inner sides via 7 and 7' and via the pulleys 8 as a uniform plastic product 12 of the cutting device 11 supplied.

The outside of the two moldings is cooled by in the housing 4 via 9 and 9 'supplied finely divided water, which at 10 and 10' is discharged again.

The process enables the continuous production of structural foams with solid and stable outer surfaces and a foamed core. Both exterior surfaces and the foamed core can consist of the same plastics.

But it is also possible to use two different plastics on each other to foam up, so that products result, both outside of which are different Plastics.

The process is varied. For example, it is also possible to have just one Use one layer of foamable plastic while the other layer is made of a layer of non-expandable plastic, i.e. a plastic without propellant, consists.

By foaming in inserts, e.g. fibrous flat structures made of natural or plastic threads, or made of metallic fibers or fibers made of glass or mineral wool, you can produce reinforced structural foams, their strength is particularly high.

The possible uses of the finished product are therefore considerable has been expanded. The manufactured products are uniform, so that even with Long-term stress does not result in the dense and solid cover layers becoming detached from the foamed ones Part occurs. In spite of the low weight, those produced according to the invention are Foams are very stable and have a high impact resistance on hard surfaces, so that containers are made for transport purposes and to hold goods of all kinds can be.

The utensils manufactured with the plastic product according to the invention are waterproof and chemical resistant and are not subject to wear and tear.

The manufacture of colored objects is possible through pigmentation, one or both of the outer sides can be given a different color than, for example the foamed core.

Claims

Claims (11)

Claims 1) Method for producing foamed plastics by mixing the plastic with blowing agents, optionally crosslinking agents and other additives and then heating, whereby one to produce a unilaterally sealed surface one side heated to a temperature T1 which is about the melting range T8 of the foamable Fnstætoffs, foams and if necessary networked while keeping the other side at a temperature T2 which is below T1 is, according to DBP .... (patent application P 20 00 737.8), characterized in that you have two layers of plastic, at least one of which is foamable, while or after the foaming of the foamable layer or the two foamable layers brings together and connects with their foamed or foamed side and keeps the two outer sides at a temperature T2, which is below that for foaming required temperature T1. 2) Method according to claim 1, characterized in that the keeps both outer sides at a temperature T2 which is below the melting range-Ts of the plastic used. 3) Method according to claim 1 and 2, characterized in that the two outer sides are cooled. 4) Method according to one or more of the preceding claims 1 to 3, characterized in that between the two layers of plastic brings in a reinforcing insert. 5) Method according to one or more of the preceding claims 1 to 4, characterized in that two layers of different plastics are used. 6) ~ Method according to one or more of the preceding claims 1 to 5, characterized in that the plastic of one or both layers cross-linked during or after foaming. 7) Method according to one or more of the preceding claims 1 to 6, characterized in that for one layer or for both layers one pre-crosslinked plastic used. 8) Method according to one or more of the preceding claims 1 to 7, characterized in that the plastic of one or both Lay into a molding, film, sheet, tape and before heating and foaming like, deformed. 9) Plastic product with solid outer surfaces and a foamed, optionally containing a reinforcing insert, manufactured according to a or more of the preceding claims 1 to 8. 10) plastic product according to claim 9, characterized in that the outer surfaces are made of different plastics. 11) plastic product according to claims 9 and 10, characterized in that that the outer surfaces and / or the foamed core are networked. Blank page