DE1704686A1 - Regenerated foam - Google Patents

Description

Concerning
"Regenerated Foam"

The invention relates to regenerated foams; H. on substances that can be formed, though you finished foam parts, z. B. Waste, connected with each other

One of the most important factors in determining the cushioning value of a foam is its load-bearing capacity. In the microstructure of a foam, for example a polyurethane foam, there is a geometric arrangement of interlocking band-like structural particles, across which membranes extend so that cells are formed. When a load is applied to the foam, the membranes undergo elastic "IJE & odrtiiation followed by a bulging of the ligament structure""flatness · ¹ (bottoming) occurs when

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the bands are pressed down until they lie tightly on top of one another, so that the foam structure can then practically be regarded as collapsed _e

The purpose of the invention is to provide a regenerated foam with improved wearability and damping properties.

The regenerated foam according to the invention, which meets these requirements, consists of small particles a first foam, which are interconnected by a second, newly formed foam, in which the latter fibers are uniformly distributed.

According to the invention, the regrind can be produced by mixing particles of a finely divided one Foam with a mixture of a foamable resin and a fibrous material; the The foamable mixture is then subjected to foaming and the foam is cured so that the particles are built into a coherent body. With this type of production occur between the incorporated Foam particles and the fibrous reinforcing material tensile forces, so that the band structure through the fibrous particles are maintained and the

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bulging or sagging under load is severely restricted. It is important that the fibers are well distributed through the entire foamable resin binder, that is, it must be a dispersion of individual, single-filament fibers, e.g. B. a mass of loose fibers, z _o B ₀ a short-fiber tow, act. The characteristic and particularly advantageous properties of the inventive products were not set when% the fibers were present only in the form of yarn or other spun or twisted products.

The fibers used can be of synthetic or natural origin. Non-reactive fibers of low absorbency, e.g. B «Cellulose fibers are preferred» The fiber length can be 1.6 to 76.2 mm, however, it is preferably between 6.3 and 19 mm. The fiber thickness can be different; it can, for example, be see 2 and 3oo to. swaying, the preferred thickness at about 50 den. lies"

The fibers may be subjected to additional treatments during or after their manufacture to increase the adhesion between the foam and the fiber and / or the physical properties of the

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to improve reclaimed foam «The preferred one The method for achieving increased adhesion is to use fibers with a rough surface used so that the foamable resin mixture penetrates into the surface irregularities of the fibers and thereby effectively cementing them together. Are fibers with a rough or irregular surface structure commercially available, for example in the form of "matted fibers" that are already roughened during their manufacture have been. Viscose fibers of this type were used in the following examples.

For the foam serving as a binder, it is also possible to use coating compounds which are reactive Represent an intermediate link between foam and fiber; for example, the fibers can be coated with polyamide resins, Alkyd resins and the like coat before they are incorporated into the foam.

The crushed finished product introduced in particle form Foam, e.g. B. Polyurethane (either polyether or polyester) foam, rubber latex, rubber sponge or cellular rubber. Rigid polyurethane foam, Cork and other lightweight materials can also be used, either individually or in combination,

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can be used for the fibrous regenerated foam. Preferably, the parts are of the swollen again verwendenen foam with an appropriate volatile solvent or pre-expanded _o The technique is British patent specification to refer to 976 26o. In the case of polyurethane or rubber particles, suitable swelling agents are e.g. B. volatile chlorinated hydrocarbons to which small additions of compatible cellulose solvents can be added in order to increase the binding force. The presence of solvents in the foamable resin composition also assists it in penetrating the surface irregularities of fibers with a rough surface.

The binder is preferably a polyurethane resin, which can be of the polyether or polyester type Foam formed is preferably soft, but can optionally also be semi-rigid or even completely rigid.

(on

For foaming, one of the] aqueous bases can work Method or steam curing are used} the foam can, however, also with the help of an anhydrous Process are formed, wherein the above-mentioned technique can be applied, in which with the aid of a Solvent a pre-expansion is effected. The latter procedure is preferred for the purposes of the invention, whether-

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usable products can probably also be obtained with the help of the other methods.

The curing of the foams can also be effected in very different ways, depending on the catalyst system used. For example, cold curing, heating under compression, curing with steam, in an oven or with the aid of microwaves are effective curing methods. The preferred mode of operation is to heat the pressurized foam between plates ₀

The fiber-reinforced regenerated foams according to the invention have high tensile strength and suffer little elongation under tension, in contrast of similar known regenerated foam products; in terms of their cushioning effect and shock absorption they are significantly superior to the known comparable products «They combine the strength of textile products, so to speak with the elastic behavior of foams and are used, for example, as carpet underlays where they replace the usual fabrics with jute on the back in the packaging industry, where their extraordinary high shock-absorbing effect is particularly valued, and also as mats or coverings for sports purposes, where increased stiffness and good abrasion resistance are particularly important.

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is partaking.

Also in the mattress and upholstered furniture industry the products according to the registration have a wide field of application, because they can be put on steel springs directly and without an intermediate layer of jute or other fibers raise.

The examples explain the invention in more detail: A.

example 1

3020 g of polyester foam waste were now crushed to a particle size of around 5 and carefully mixed in a suitable vessel with 905 g of viscose rayon fibers (50 den.) With a length of 12.7 mm. Separately, 34-8 g of a foamable polyester resin (molecular weight 3ooo) were mixed with 285 g of methylene chloride, whereupon 118.5 g of toluene diisocyanate (6o: 4o), a small amount of an amine catalyst (6.9 g of catalyst SPB - 1.CoI ₀ ) and a stabilizer \

for silicone foams (3.4 g silicone B.727 - Goldschmidt AG, Essen) were added. The mixture was stirred vigorously for one to two minutes and then combined with the mixture of polyester foam and viscose fibers and processed on the machine for 4 to 5 minutes. The mass was then poured into a heated mold, pressed into a block of 28 dm ⁵ and thermoset.

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Example 2

4,3oo g latex foam waste were comminuted to a particle size of about 2.5 mm and mixed with 1,290 g viscose material from threads of 50 den. and about 9.5 mm in length mixed. Separately from this, 875 g of a lockable polyether were used resin (Daltocel To 56 - I.C.I.) in 346 g of methylene chloride solved. 9.6 g of tin octoate and 4.3 g of silicone foam stabilizer and also 307 g were added to the solution Toluene diisocyanate (Suprase EN - I.C.I., 8o * 2o) added.

After brief stirring, the mixture was combined with the fiber-containing foam mass and stirred vigorously for a further five minutes. Then the mass was poured into a heated aluminum mold
pressed and thermoset.

■ 5 aluminum mold filled into a block of 28 dm ver

Claims

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Claims (1)

DB. ING. F. WUESTHOFF MUNICH » DIPL. ING. G. PULS schwbigehsthasse s DH. E. τ. PECHMANN «uroi. 22 OO 31 1 "7 Ω Λ fv Q R PAHNTANWiITE P «" ci "" xi ° "XcH./ ■ 9 1A-33 741 Claims 1 β Regenerated foam from small particles a first foam, which are interconnected by one made of a second foam existing matrix, marked yy through individual stripes uniformly distributed in the second foam. 2. Foam according to claim 1, characterized in that in the second foam component distributed fibers have a rough surface and that the second foam in the surface irregularities the Pasern has penetrated. 3 »Foam according to claim 1 or 2, characterized in that the piping has a length from 1.6 to 76.2 mm, preferably from 6.3 to 19 mm and a thickness of 2 to 300 ovens., preferably of about 5o den. exhibit" 4. Process for the production of a regenerated foam according to claims 1-3 »characterized by that a fiber-shaped material is mixed 209844/0907 - 2 - with a foamable resin and particles of a crushed foam until the fibers are in the foamable Mixture are uniformly distributed, whereupon the mixture is foamed and cured. 5ο Method according to claim 4, characterized in that the fibers have rough surfaces α and that a volatile solvent with the foamable Resin mixed to facilitate the penetration of the resin into the surface irregularities of the fibers. 6. The method according to claim 5 »characterized in that the foamable resin composition is foamed in the absence of water and that such a volatile solvent is present that causes the foam particles to swell, W 7ο method according to claim 4, 5 or 6, characterized in that the fibers are provided with a coating before they are used which supports the adhesion of the foamable resin to the fibers. 209844/0907 AA 8. The method according to any one of claims 4-7 »characterized in that the hardening by heating of the foam is effected under pressure between plates. 209844/0907