DD292472A5 - DISPLAYABLE COATING MASS FOR SOUND-CLOSING - Google Patents

Abstract

The invention relates to a sprayable sound deadening composition containing not more than 30% aqueous Kunzharzdispersion, a mixture of flame retardant filler of the hydrargillite type and acoustically active filler, fibers, of which at least a part are water-dispersible inorganic fibers, water and possibly other additives , wherein the Fuellstoffmischung has an optimized packing density. The coating compositions obtained are low in binder, flame-retardant, environmentally friendly and have improved acoustic properties and a reduced tendency to form risks during drying. {Coating composition, sprayable; Kunz resin dispersion; flame retardant filler; low binder, flame retardant; environmentally friendly, improved acoustic properties}

Description

Field of application of the invention

The invention relates to a spriubare coating composition for sound attenuation based on aqueous Kunzharzdisporsion, fillers and fibers.

Characteristic of the known state of the art

In the manufacture of vehicles, machines and equipment nowadays almost exclusively very thin-walled sheets are used. By mechanically moving parts or running motors, these thin-walled sheets are inevitably vibrated and therefore emit sound. To reduce this sound radiation, therefore, these sheets are provided with sound-absorbing coatings, so-called Antidröhnbelägen particular in automotive and in the production of household appliances.

Sound-absorbing coatings based on aqueous or solvent-containing synthetic resin or bitumen dispersions are known. Fillers and / or fibers are added to these coatings to reduce the flammability and to improve the stability on vertical walls and / or the sound-damping properties. The coating compositions used hitherto are either relatively binder-rich systems which, while having only a slight tendency to form cracks during the drying process, are readily inflammable or relatively low-binder systems which show better fire behavior but do so to a high degree tend to crack.

Gerado in view of the growing environmental awareness and increased fire protection requirements, especially in new technical developments, such. As in high-speed trains, gaining importance, it is to provide coating compositions for soundproofing available that are flame retardant despite low binder content. In addition, such coating compositions in a simple manner, for. Example, by means of the spraying process, can have increased sound damping properties and be substantially free of solvents, halogens, heavy metals and asbestos.

Object of the invention

The invention provides a coating composition that is a binder type, flame-retardant and environmentally friendly and has improved acoustic properties, and a reduced tendency to crack during the drying process.

Explanation of the WO of the invention

The invention has for its object to provide such coating compositions available.

This object is surprisingly achieved by the sprayable coating composition according to the main claim, wherein the subclaims relate to preferred embodiments of the invention.

The sprayable coating composition according to the invention for soundproofing contains not more than 30% by weight, preferably 10 to 15% by weight, of an aqueous synthetic resin dispersion or a mixture of different synthetic resin dispersions and is thus binder-poor. Suitable synthetic resins are generally homopolymers, copolymers and / or hydrocarbon resins with glass transition temperatures below room temperature, which are capable of forming tacky films and aqueous, solvent-free and stable even at high filler contents dispersions.

Preferably find aqueous resin dispersions based on 5 of z. As polyvinyl acetate, ethylene-vinyl acetate, styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene-styrene polymer, polyurethane and / or acrylic acid ester copolymer, and particularly preferably based on acrylic acid ester copolymer use.

The solid content of the coating composition is not less than 50% by weight, and preferably 60 to 70% by weight.

The total content of the coating composition according to the invention of 15 organic constituents is not more than 25% by weight and preferably from 10 to 15% by weight, based on the solids content.

Furthermore, the coating composition contains as a flame retardant filler substantially heavy metal and halogen-free inorganic compounds or minerals which dehydrate at elevated temperature, in an amount of not less than 10% by weight and preferably 25 to 35% by weight, based on the solids content. Examples of these are magnesium hydroxide, magnesium sulfate heptahydrate, alums and / or hydrargillite, with hydrargillite being preferred. The thus flame-retardant coating composition is free of halogens and heavy metals, which contributes significantly to their excellent environmental compatibility.

The content of acoustically active fillers is not less than 20% by weight and preferably up to 60% by weight, based on the solids content. Examples of usable acoustically active fillers are mica, slate meal, montmorillonite; Glass or metal flakes, graphite, talc and / or clay minerals, with mica being preferred.

An essential characteristic of the coating composition of the invention is that the mixture of flame retardant and acoustically active fillers is constructed so that when applying screen passage D of the filler mixture in wt .-% on the ordinate against the grain diameter d of the particles of the filler mixture in millimeters the abscissa gives a grain characteristic which is essentially the equation

D =

obeyed, where D is the sieve passage in% by weight, d is the grain diameter in millimeters and d _{max is} the maximum grain diameter in millimeters. The curve corresponding to the above equation is called the Fuller curve and indicates the grain size distribution required to achieve the closest packing of a grain. Due to this optimized particle size distribution, the voids in the filler mixture are reduced to a minimum.

Surprisingly, despite disregarding the different particle shapes of the fillers used, a coating composition having a filler mixture of this type has an optimum packing density if the coating composition additionally contains not more than 10% by weight of fibers of which at least some are water-dispersible inorganic fibers. The coating composition preferably contains 0.5 to 2 wt .-% fibers, based on the solids content. Examples of usable fibers are organic fibers such as cellulose fibers, and examples of inorganic water-dispersible fibers are water-dispersible mineral or glass fibers.

The maximum grain diameter of the fillers used is in the range of 200 to 1000 pm, and preferably in the range of 300 to 400 μπι.

As a further component, the sprayable coating composition contains water in an amount sufficient to balance the weight balance.

In addition, the coating composition according to the invention may optionally contain additives, the z. As for frost stabilization, wetting improvement of the fillers and fibers, for fungicidal and microbial preservation, serve for thickening and / or corrosion inhibition.

Although the coating composition according to the invention has only a low binder content, no cracking occurs during its drying. In addition to the reduced tendency to cracking, the coating composition according to the invention has increased sound damping properties and improved fire behavior. The coating composition can be brewed in a simple manner by means of conventional techniques, preferably by spraying, onto sound-radiating surfaces. Here, the increased stamina on vertical surfaces proves to be another advantage. Subsequently, the applied coating composition is dried by conventional methods and cured.

In the preparation of the coating composition according to the invention for sound damping, the essential components and optionally used additives are processed in suitable conventional kneading or stirring machines with the highest possible mixing efficiency and shearing to a homogeneous mass.

It is preferred that first the selected fillers are mixed as gently as possible together with the well-digested fibers, the water and a small portion or without acting as a binder resin dispersion. After the homogenization of this mixing as far as possible then the addition of the remaining resin dispersion takes place.

Exception example

To prepare a coating composition according to the invention, the components below were mixed in a mixer. About 40% of the total amount of water as well as the additives and the fibers were initially charged and briefly mixed. Subsequently, a mixture of the specified fillers, which had a Fuller curve obeying grain size distribution, and the remaining amount of water in any order in the mixer. After extensive homogenization of this premix, the aqueous synthetic resin dispersion was added while the mixer was running. To avoid possible damage to the synthetic resin dispersion, the mixing vessel was cooled during the mixing process.

Table "

Components% by weight

Synthetic resin dispersion of 8.25% by weight

Synthetic resin and 6.75% by weight of water 15.0

Hydrargillite (Al (OH ₃ ) 20.0

acoustically active fillers 35.0

organic fibers 0.5

inorganic water-dispersible fibers 0.5

Water 26.0

Isopropanol (antifreeze) 2.0

Additives (biocides, surfactants) 1,0

The sprayable coating composition obtained in this way had the following properties:

Cone penetration (DIN ISO 2137):

Solid content (DIN 53216): ν

PH value:

specific weight, wet:

specific weight, dry: loss factor according to DIN 53 440 bsi 20 "C, 200 hertz on 1 mm sheet steel

at 1.5 times sheet thickness:

with double sheet thickness: non-combustible to DS 899/35

Flammability degree - degree of development -

Tropfbarkeitsgrad

(Test criteria of the German Federal Railways): Flame retardant according to DIN 4102 / Teih, class B1

-1

330 x ± 30 x 10 65 ± 1% 9 to 10

1.4 ± 0.1 g / cm ³ 1.2 ± 0.1 g / cm ³

at least 0.13 at least O, 2O

4-4-4

mm

During the drying process of such a coating composition, no cracking occurred.

Claims (11)

1. Sprayable coating composition for sound damping based on aqueous synthetic resin dispersion, fillers and fibers, characterized in that they a) not more than 30% by weight of an aqueous synthetic resin dispersion or a mixture of different synthetic resin dispersions, b) a filler mixture having a maximum grain diameter in the range of 200 to 1000 ml i) not less than 10% by weight, based on the solids content, of substantially heavy metal and halogen-free inorganic compounds or minerals which rehydrate at elevated temperature, as a flame retardant filler and ii) not less than 20% by weight of acoustically active fillers, based on the solids content, c) not more than 10% by weight of fibers, based on the solids content, of which at least one Part of water-dispersible inorganic fibers, d) water and e) optionally containing conventional additives, wherein no more than 25 wt .-% of organic constituents, based on the solids content, are present, the solids content is not less than 50Gew .-% and the filler mixture is constructed such that during application of the sieve passage D of the filler mixture in wt .-% on the ordinate against the grain diameter d of the particles of the filler mixture in millimeters on the abscissa results in a grain characteristic, which is essentially the equation D = obeyed, where D is the sieve passage in% by weight, d is the grain diameter in millimeters and d _{max is} the maximum grain diameter in millimeters. 2. Coating composition according to claim 1, characterized in that it contains 10 to 15 wt .-% aqueous resin dispersion. 3. Coating composition according to claim 1 or 2, characterized in that the solids content is 60 to 70Gew .-%. 4. Coating composition according to one of claims 1 to 3, characterized in that it contains 10 to 15% by weight of organic constituents, based on the solids content. 5. Coating composition according to one of claims 1 to 4, characterized in that it contains 25 to 35 wt .-% flame retardant filler, based on the solids content. 6. Coating composition according to one of claims 1 to 5, characterized in that it contains 40 to 60% by weight of acoustically active fillers, based on the solids content. 7. Coating composition according to one of claims 1 to 6, characterized in that it contains 0.5 to 2Gew .-% fibers, based on the solids content. 8. Coating composition according to one of claims 1 to 7, characterized in that the filler mixture has a maximum grain diameter in the range of 300 to 4Ρϋμιτι. 9. Coating composition according to one of claims 1 to 8, characterized in that it contains as acoustically active fillers mica, shale meal, montmorillonite, glass or metal flakes, graphite, talcum '·· ' .. or clay minerals. 10. Coating composition according to a Jer claims 1 to 8, characterized in that it contains as a flame-retardant filler hydrargillite, magnesium hydroxide, magnesium sulfate heptahydrate and / or alum. 11. Use of the coating composition according to any one of claims 1 to 10, characterized in that it is used for sound damping of sound-emitting surfaces by applying the coating composition to the surfaces and then drying the coating.