SU1647012A1 - Method for preparing reinforced foam plastic - Google Patents

Abstract

The invention relates to the technology of reinforced foams and can be used in the production of plastic racing skis and in other areas of technology. The invention makes it possible to increase the strength of reinforced polystyrene during bending due to the fact that the reinforcing fibrous filler is composed of power and spacer layers, and as the latter elastic flexible fiberglass web of synthetic fiber is used, while the thickness of the reinforcing filler in a compressed state is chosen equal to the thickness a layer of liquid reaction mixture in the form of 3 sludge., 1 tab.

Description

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The invention relates to the technology of reinforced foams and can be used in the manufacture of plastic racing skis and in other areas of technology.

The aim of the invention is to increase the strength of the reinforced foam in bending.

FIG. 1-3 depicts a flow chart of the method.

The method of producing reinforced foams is carried out as follows.

Liquid reaction mixture 2 to a certain level of ha is poured into form 1 (Fig. 1), then a certain amount of reinforcing filler consisting of power 3 and distance 4 layers of total thickness b is introduced into the mold cavity, while the thickness of the reinforcing filler is chosen so that it is in a compressed state (Fig. 2) equal to the thickness of the layer of liquid reaction mixture in the form. Then (Fig. 2) the upper punch 5. tightly entering the mold cavity and having air channels 6. The reinforcing filler is fully pressed into the mixture, removing the air and impregnating it with the liquid reaction mixture. In the process of foaming, under the action of foaming pressure, the punch gradually moves to the final (upper) position (Fig. 3) and the foam with a thickness hc cures in the mold.

Due to the presence of spacer layers, the method allows to obtain reinforced foams with increased flexural strength by imparting a predetermined distribution and configuration of force layers across the thickness of the foam. The spacing layers 4 reinforcing filler are not

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The force layer m 3 is allowed to lose a predetermined thickness distribution during the impregnation of the reinforcing filler with the liquid reaction mixture (Fig. 2). In the process of subsequent foaming, the power layers of the reinforcing filler receive a predetermined distribution in the material under the action of two main factors — foaming pressure and web-elasticity.

The spacing layers from the power layers differ in their functional purpose. The main purpose of the strength layers of the reinforcing filler is to reinforce the material, and the distance layers are to give the strength layers the required distribution and configuration over the thickness of the foam.

Example 1. To obtain a reinforced foam with the distribution of the power layers of the reinforcing filler in the surface layers of the foam, the method is carried out as follows. To obtain a polyurethane foam matrix, 382.5 g of liquid reaction mixture is taken, which is prepared according to the following technology: 150 g of polyester A-326M, 1.5 g of water and 21 g of freon-11 are poured into a plastic container. The contents of the vessel are stirred using a disk stirrer (2800 rpm) for 5-10 seconds to homogenize the mixture. After that, 210 g of polyisocyanate B is added and the contents of the vessel are stirred for 5-6 seconds with the aid of a mixer. Preliminary, the reinforcing filler consists of four power and four distance layers as follows: two layers of glass mat — four layers of batt — two layers of glass mat. VETROTEXR M-113-10Tech glass mat (manufactured by EVETEX TEXTILGLAS G MVN (FRG) with a surface density of 140 g / m2) is used as the strength layers of the reinforcing filler, and elastic, voluminous, thin-fiber polyester fiber with surface density of 100 ± 8 g / m2.

The prepared liquid reaction mixture is evenly poured into the form. Immediately after pouring, a reinforcing filler previously composed of power and distance layers is inserted into the mold cavity from above. Then, the upper punch, which tightly enters the mold cavity and has air channels, the reinforcing filler is fully pressed into the mixture, removing the air and impregnating it with the liquid reaction mixture. In the compressed state in the liquid reaction mixture due to the elasticity of the spacer layers, the arrangement of the layers is not disturbed. In the process

due to the foaming pressure and due to the elasticity of the spacer layers, the compressed reinforcing filler increases its thickness and

the force layers are distributed in parallel in the surface layers of the foam. The punch under the action of the mentioned forces gradually moves to the final (upper) position. The foam is cured in the mold. Reinforced foam contains 20% by weight of reinforcing filler, which includes 12% by weight of glass mat and 8% by weight of batt, has a density of 130kg / m3, a mass of 312 g. Strength characteristics at

bending is determined on specimens with a cross section of 28 x 40 mm on a base of 200 mm. The breaking load of the specimens is 505 ± 58 N, the flexural strength is 3.14 ± 0.28 MPa.

Example 2. Reinforced foam is prepared according to Example 1. Azhur-42P glass grid and polyisocyanurate matrix are used as power layers. Reinforcing filler

They are composed of power and distance layers as follows: four layers of glass mesh — four layers of batt — four layers of glass mesh. To obtain a polyisocyanurate matrix foam, 426 g of a liquid reaction mixture is prepared, which is prepared as follows. - In a plastic vessel, 60 g of Laprol-2002, 6 g of CEP-2 emulsifier, 36 g of refrigerant-113 and 24 g of DMA alkofen (made

the company Curing Adent K54, England /. The contents of the vessel is stirred using a disk stirrer (2800 rpm) for 5-10 s to homogenize the mixture. 300 g of polyisocyanate B are then added and

mix the contents of the vessel for 5-6 seconds using the agitator. Reinforced foam contains 14.7 wt.% Reinforcing filler, which includes 7 may. % glass mesh and

7.7 wt.% By weight, has a density of 128 kg / m3, a mass of 307 g. The breaking load of the specimens during bending is 532 ± 66 N, and the bending strength is 3.57 ± 0.44 MPa.

Example 3. To obtain a reinforced foam with a curved configuration of the strength layers of the reinforcing agent on the filler (Fig. 3), the method is carried out as in example 1, using the same materials for the reinforcing filler and the matrix

foam, but the strength layer of the reinforcing filler is made up of deuh layers of glass mat, lining it on both sides with spacer layers of batt: from the bottom in the middle and from the top along the edges of the power

layer is placed four layers of batting, after that one layer of glass mat is put on top and bottom. When pressed into the reaction mixture due to the elasticity of the webs, the force layer (curved) is pressed to the punch in the middle and to the bottom of the mold at the edges. The foaming pressure and the elasticity of the web increase the thickness of the reinforcing filler, while the relative distribution of its layers is maintained in the finished reinforced foam. Reinforced foam contains 20 wt.% Reinforcing filler, which includes 12 may. % of glass mat and 8% by weight of batt, has a density of 130 kg / m3, weight 312 g. The breaking load of the fabric is 592 ± 61 N. The bending strength is 3.97 ± 0.47 MPa.

Example 4. To obtain a reinforced foam with parallel arranged and distributed across the thickness of the foam, the strength layers of the reinforcing filler, the method is carried out as in Example 1, but using polyurethane foam is a cyanuric foam matrix. The reinforcing filler is made up of four power and four spacer layers as follows: glass mat - batt layer - glass mat - two batt layers - glass mat - batt layer - glass mat. To obtain a polyurethane-isocyanurate matrix foam, 405.9 g of a liquid reaction mixture is taken, which is prepared as follows. 36 g of lapromolz-294, 36 g of laprol-503M, refrigerated-11, phospholiol P, 36 g of trichloroethylphosphate, 3.6 g of CEP-2 and 1.8 g of a 50% aqueous solution of acetate are poured into a plastic vessel. Kali. The contents of the vessel are stirred using a disk stirrer (2800 rpm) for 5-10 seconds in order to homogenize the mixture, 225 g of polyisocyanate B is added and the contents of the vessel are stirred for 5-6 seconds using a disk stirrer. The reinforced foam contains 18.2 mas.% Reinforcing filler, which includes 11% by weight of glass mat and 72 parts by weight of a batt, has a density of 141 kg / m and a weight of 340 g. The breaking load of the samples is 473 ± 57N.

Comparative characteristics of reinforced foam, obtained by the proposed and known methods are shown in the table.

As can be seen from the table, the proposed method allows to increase the strength of the reinforced foam during bending.

Claims (1)

The method of obtaining reinforced polystyrene, including pouring a liquid reaction mixture into a mold, placing a reinforcing fiber filler, impregnating a filler by pressing into the reaction mixture, and then foaming it to a predetermined volume, characterized in that, in order to increase the strength of the reinforced foam during bending, the reinforcing fibrous filler is composed of power and distance layers, and the latter use elastic, bulky fiberglass batt of synthetic fiber and, wherein the thickness of the reinforcing filler in the compressed state is selected equal to the thickness of the liquid layer of the reaction mixture in the mold. 1647012 FIG. one FIG. 2