RU2196679C1 - Method for production of moulding sound-absorbing material - Google Patents

Abstract

FIELD: sound proofing of buildings and vehicles. SUBSTANCE: method is based on milled urethane foam mainly of the open-type porous structure with a density of 15-70 kg/cu.m passing through a screen with mesh of 7 mm, it consists in its mixing with the binder, mechanical packing in a mould to a density of 100-160 g/cu.m, then - hardening of the packed material at a temperature of 130-150 C for 15-25 min. Urea-formaldehyde resin is used as binder with the relation of ammine and formaldehyde groups equal to 1:0.8, modified by melamine, with the content of melamine from 1-100 mg, and by diethyleneglycol with the content diethyleneglycol within 1-20 mg for 100 mg of polymer, with a hardening catalyst, or 45-50-% aqueous dispersion of acrylic copolymer with relation of methyl methacrylate: butylcrylate: methacrylic acid = 15:80:5 mas.%, or 45-80-% aqueous dispersion of polyvinyl acetate modified by epoxy oligomer taken within 70-100 mg for 100 mg of polyvinyl acetate. The binder is taken within 10-55 mas.%. Used as the hardening catalyst is a 25-% aqueous solution of ammonium chloride at a relation resin: catalyst = 97:3 mas.% in terms of a dry substance. The material may include particles of milled natural or synthetic fibre and/or polyethylene terephthalate film passing through a screen with a mesh of 7 mm, 1-20 mas.% for 100 mas.% of milled urethane foam. The material sound-absorbing factor within a frequency range from 800 to 6300 Hz makes up to 0.20-0.95. EFFECT: expanded range of sound-absorbing materials. 3 cl, 1 tbl

Description

 The invention relates to sound-absorbing materials made primarily on the basis of open-porous polymeric materials, in particular polyurethane foam (PUF), intended, for example, for use, in particular in automotive machinery, to isolate the vehicle interior from engine noise, as well as to reduce internal noise engine compartment space. The material can be used both independently and as a part of layered ones, including molded materials.

 The prior art.

 Open-cell resilient foams are increasingly being used for sound and heat insulation of buildings and cars. The resulting process and consumer waste must be recycled.

There is a method of improving the soundproofing properties of foams due to the additional processing of molded foam boards by multiple compression of 60 ÷ 90% of the original thickness. After processing, the density of the plates increases from 17 ÷ 30 to 20 ÷ 35 kg / m ³ . This method is used for processing block polystyrene foam, from which plates will then be obtained [application 4330314, Germany, IPC В 29 С 67/20, publ. 1995].

 A known method of producing materials from PUF waste, in which the waste is crushed to particles <50 mm in size, and granulate is prepared so that the content of particles with a size of ≤3 mm is not more than 15%, and particles with a size of 3 ÷ 15 mm - 30 ÷ 70% . Wastes thus prepared are treated with a special binder in an amount of 65–94%. From the resulting mass, plates are formed, which are then coated with bilateral or one-sided plates - gypsum, felt, tin, from synthetic materials, or blocks are formed, from which, after 24 hours of exposure, shaped elements or plates are pressed, which are then wrapped [Method for the disposal of waste porous products, particular polyurethane foams. Sposob utylizacji odpaclow tworzyw porowatych, zwiaszcza pianek poliuretanowych, Polim.-tworz. Wielkoczasteczk, 1994, 39, 2, p. 128].

A known method of producing heat-insulating products, consisting of a porous shaped part of an apparent density of 50 ÷ 350 kg / m ³ , preferably 100 ÷ 250 kg / m ³ , obtained by grinding hard plastic foam to obtain powder or flakes and mixing them with a binder while sequential pressing and molding [RF patent 2154577, IPC B 32 V 5/18, 7/02, publ. 05/10/1999].

 A known method of producing parts from polystyrene using recyclate [application 4333330, Germany, IPC B 29 C 67/20, publ. 04/06/1995], selected as a prototype. The essence of the claimed method is as follows: the waste foam is pre-crushed into flakes with particle sizes of 0.1 ÷ 50 mm, which are then mixed with a binder and hardener. The result is a mixture of the composition (in parts by weight): crushed polystyrene -100; binder - 5 ÷ 50; hardener - 0.1 ÷ 5; water - 5 ÷ 50.

The resulting mixture is loaded into a mold, where they are mechanically compacted to a density of 20 ÷ 50 g / l. Then the form is blown for 0.5 ÷ 60 min with water vapor with a temperature of 104 ÷ 158 ^o C and a pressure of 0.1 ÷ 5 bar. In conclusion, the resulting billet is placed in a furnace with a temperature of 180 ÷ 250 ^o C for 0.15 ÷ 6 hours. As a result, a high-quality part suitable for use in construction, automotive and other industries.

 The objective of the invention is to expand the arsenal of sound-absorbing materials designed to reduce the noise level in the car interior, as well as external noise, in particular due to the use of crushed open-porous flexible polyurethane foam, the source of which is technological waste or waste materials and products containing PUF.

 SUMMARY OF THE INVENTION

The essence of the proposed method for producing a sound-absorbing molding material is that particles of crushed polyurethane, for example, in a rotary or knife grinder, passing through a sieve with a mesh size of 7 mm are mixed with a polymer binder, mechanically compacted in a form to a density of 100 ÷ 160 g / m ³ and cured at a temperature of 130 ÷ 150 ^o C for 15 ÷ 25 minutes As a polyurethane foam, elastic polyurethane foam of predominantly open-porous structure with a density of 15 ÷ 70 kg / m ^{3 is used} , and as a binder, a urea-formaldehyde resin with a ratio of amine and formaldehyde groups of 1: 0.8, modified by melamine, with a melamine content of from 1 to 100 mg and diethylene glycol with a diethylene glycol content of from 1 to 20 mg per 100 mg of polymer, with a curing catalyst, or 45 ÷ 50% aqueous dispersion of acrylic polymer with a ratio of methyl methacrylate: butyl acrylate: methacrylic acid = 15: 80: 5 wt. %, or 45 ÷ 50% aqueous dispersion of polyvinyl acetate (PVA), modified with an epoxy oligomer, taken in an amount of 70 ÷ 100 mg per 100 mg of PVA, with a binder of 10 ÷ 15 wt.ch. at 100 max. PPU.

 To accelerate the curing process of a binder based on a modified urea-formaldehyde resin, a curing catalyst is used, for example a 25% aqueous solution of ammonium chloride. The ratio of resin and curing catalyst, calculated on the dry matter, is 97: 3 wt.%, Respectively.

 The moldable composition may further include other ground materials also passing through a sieve with a mesh size of 7 mm, for example, fabrics and non-woven materials based on natural or synthetic fibers, film materials (for example, polyethylene terephthalate), in an amount of 1 to 20 wt.h. at 100 max. PPU.

 A urea-formaldehyde resin-based binder composition is prepared in a container with a mixer, where the resin is loaded, and with the mixer working, a curing catalyst is added - an aqueous 25% solution of ammonium chloride. Stirring is carried out for 5 minutes.

 A binder composition based on a PVA dispersion is prepared in a container with a mixer, where the PVA dispersion is loaded, and with a rotating mixer with a frequency of 1400 ÷ 1700 rpm, an epoxy oligomer is introduced, for example, grade ED-20 according to GOST 10587-84. Mixing is carried out for 15 ÷ 20 minutes

 The crushed polyurethane foam is treated with a binder in a high-speed mixer for 8 ÷ 15 minutes with a mass ratio of 10 ÷ 15 wt.h. binder per 100 wt. h. PPU.

 The material is formed in the mold of a punch-matrix type. Before loading the mixture, the mold is internally treated with silicone grease.

The moldable composition is evenly distributed over the surface of the matrix and mechanically compacted to a density of 100 ÷ 160 g / m ³ . Then form is mechanically fixed in this position and placed in a heat chamber with a temperature of 130 ÷ 150 ^o C, where it is held for 15 ÷ 25 minutes. Then the mold is removed from the heat chamber, opened and the formed material is removed.

 Information confirming the possibility of carrying out the invention.

Polyurethane foam with a density of 25 kg / m ³ , crushed in a knife-type grinder, is sieved through a sieve with a mesh size of 7 mm.

 Then a binder composition is prepared on the basis of urea-formaldehyde resin modified with melamine in an amount of 10 mg per 100 mg of polymer and diethylene glycol in an amount of 10 mg per 100 mg of polymer, with a curing catalyst - 25% aqueous solution of ammonium chloride. The specified resin is loaded into a container with a stirrer and, with the stirrer operating, a curing catalyst is added. Stirring is carried out for 5 minutes.

The ratio of urea-formaldehyde resin modified with melamine and diethylene glycol and the curing catalyst, calculated on the dry matter, is 97: 3 wt.%, Respectively
To the crushed polyurethane foam add crushed polyethylene terephthalate film and crushed polyester fiber in an amount of 1 wt.h. and 5 parts by weight respectively, 100 parts by weight PPU and the resulting mixture is treated with a binder in a high-speed mixer for 10 minutes at a mass ratio of 12 parts by weight resin per 100 parts by weight PPU.

The material is formed in the mold of a punch-matrix type. The mold is preheated in a heat chamber at a temperature of 140 ^o C for 15 minutes, and the inner surface of the mold is treated with silicone grease.

The mixture is evenly distributed over the surface of the matrix and mechanically compacted to a density of 100 g / m ³ . Then the mold is fixed in this position and placed in a heat chamber with a temperature of 140 ^o C, where it is kept for 20 minutes. Then the mold is removed from the heat chamber, opened and the formed material is removed. The thickness of the finished material is 7 mm.

 Get the material with a sound absorption coefficient in the frequency range 800 ÷ 6300 Hz - 0.40 ÷ 0.95.

 Examples of the invention and quality indicators of the materials obtained are given in the table.

Claims (3)

1. A method of producing a molded sound-absorbing material based on crushed foam, comprising mixing it with a binder, mechanical compaction in the mold and curing at elevated temperature, characterized in that crushed elastic polyurethane foam, mainly an open-porous structure with a density of 15-70 kg /, is used as a foam m ³ passing through a sieve with a mesh size of 7 mm, and a urea-formaldehyde resin with a ratio of amine and formaldehyde groups of 1: 0.8 is used as a binder, modified with melamine, with a melamine content of 1 to 100 mg and diethylene glycol with a diethylene glycol content of 1 to 20 mg per 100 mg of polymer, with a curing catalyst, or a 45-50% aqueous dispersion of an acrylic copolymer with a ratio of methyl methacrylate: butyl acrylate: methacrylic acid = 15: 80: 5 wt. %, or 45-50% aqueous dispersion of polyvinyl acetate, modified with an epoxy oligomer, taken in an amount of 70-100 mg of oligomer per 100 mg of polyvinyl acetate, and the binder is taken in an amount of 10-15 wt. hours per 100 wt. including polyurethane foam, and the mechanical compaction of the material is carried out to a density of 100-160 g / m ³ and molding is carried out at 130-150 ^o C for 15-25 minutes  2. The method according to p. 1, characterized in that the material further comprises particles of ground natural or synthetic fiber and / or polyethylene terephthalate film passing through a sieve with a mesh size of 7 mm in an amount of from 1 to 20 wt. hours per 100 wt. including crushed polyurethane foam.  3. The method according to p. 1 or 2, characterized in that the material is molded with a thickness of 7-10 mm

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