DE2162984A1 - Sound absorbing laminate and adhesive therefor - Google Patents

Description

The invention relates to a sound-absorbing laminate and an advantageous one for its manufacture Adhesive. In particular, the invention relates to a sound-absorbing laminate having a core part made of a multitude of rectilinearly ribbed connected foils, which are inclined and crossed at an angle to one another and whose rib axes are oblique to the longitudinal plane of the laminate, one with one side of the core part connected continuous outer layer and one connected to the other side of the core part perforated outer layer. The outer layers and the core part are preferably connected with the aid of an adhesive which a polyurethane resin, a diamine curing agent, a trifunctional alcohol amine and an epoxysilane consists.

Acoustic laminates are known and in numerous patents has been described. Most thin laminates are for many industrial uses useful, but fail in at least one of several important categories for a Soundproofing element are essential. So is

meant that most commercially available laminates does not sufficiently reduce sound transmission or absorb airborne noise to be able to they are used, for example, for cladding for data processing equipment, Ultrasonic devices, motors, turbine housings, intake and exhaust silencer systems, typewriter cabins, Gear and belt transmissions, audiometric test chambers, sound measurement rooms, housings for sonochemicals Devices and the like could be used. When it comes to products such as soundproof doors and / or Shields etc. are processed, they are also sometimes too heavy, especially for aircraft. Many Commercial laminates also fail in practice because they are incapable of using mechanical energy, that is to say Shocks to be absorbed in the event of impact stress and / or because they are not resistant to mold and vapors absorb.

Adhesives made from polyurethane resins, glycidyl-containing esters and ethers, diamine hardeners and epoxysilanes which are suitable for joining metal to metal are already known (see US Pat. No. 3,391,054). While these known adhesives are excellent for many purposes, they suffer from the disadvantage that they do not have the vibration dampening properties which would be required for their use in some fields. It has now been found that the vibration-damping properties of these known adhesives can be improved by introducing a trifunctional alcohol amine into the adhesive composition, while the shear strength of the adhesives is retained. This result is very surprising in view of the relatively small amounts of alcohol amine added.

The invention relates to a sound-absorbing laminate structure composed of two outer layers and a core part, which is characterized in that the core part is made up of a plurality of thin straight ribs

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Sheets of construction material that join together at all face-to-face contact surfaces are connected and the ribs are inclined at an angle and cross over at neighboring foils and thereby Form rigid truss-like structures, with the longitudinal axes all straight ribs of the multitude of foils are inclined to the longitudinal plane of the laminate, consists that an uninterrupted outer layer is connected to one of the sides of the core part and that with the side of the core part which is opposite the uninterrupted outer layer, a perforated outer layer is associated with an open area proportion of 5 to 50%.

According to a preferred embodiment of the invention the outer layers are connected to the core part by means of an adhesive, which consists of a uniform mixture (a) a polyurethane prepolymer, (b) 45 to 99% of the stoichiometrically equivalent amount of a diamine curing agent, based on the content of (a) free NCO, (c) 1 to 55% of the stoichiometrically equivalent amount of a trifunctional alcoholamine, based on the Content of (a) free -NCO, and (d) 0.1 to 15 percent by weight of a glycidoxyalkyltrialkoxysilane, based on the total weight of the adhesive.

Laminates according to the invention have excellent properties They have sound absorption properties, are light in weight, absorb mechanical energy, are mold-resistant and do not absorb fumes.

The improved laminates are for purposes such as components, for example aircraft parts, boat parts, automobile parts, dishwashers, cladding, furnace housings, Industrial commodities such as barrel lathes,

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Channels and suction shafts, housings for industrial grinders, Cladding for buildings, electronic cladding Devices, acoustic filters, instrument housings, sound suppression chambers, housings and silencers for ultrasound Ischweißger ate, housing for ultrasonic dispersing devices, Housings for, turbines and jet engines, exhaust and Suction modules and silencers, housings for sonochemical devices and the like are advantageous.

Figure 1 shows a double cross-section of a laminate, wherein the reference numeral 1 is a straight rib Designates film, while reference number 2 designates the subsequent straight ribbed flat film. the connected foils form a framework-like core part 3, as shown in FIG. As can be seen the ribs of the alternating foils are inclined at an angle and cross each other on adjacent foils. The longitudinal axes all of the ribs of each layer are inclined to the plane of the laminate. Numeral 4 denotes a metal or Plastic layer with holes 5 therein, which by means not shown with the truss-like Core part 3 is connected. The side of part 3 opposite this layer 4 is also through Means not shown connected a continuous layer 6, which are also made of plastic or metal can.

FIG. 2 shows a cut-open representation of the laminate from FIG. 1, but with only a single cross section through part 3. As can be seen, the core part 3 consists of a ribbed truss-like configuration, while the outer layer 4 has perforations 5 and layer 6 is solid.

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The laminate according to the invention has, as already briefly was mentioned, a surface layer made of metal or plastic, which is perforated in its cross-sectional area and preferably also has a desirable surface aesthetic appearance, corrosion resistance, mechanical strength and durability. The surface layer is connected to a core part which is usually thicker in cross-section than the surface layer is and consists of a large number of straight ribbed foils, which are connected to each other at all contact surfaces connected face to face, usually by gluing, and in which the ribs are alternating Foils are inclined at an angle and intersect with those of adjacent foils, so that the crossed ribs form rigid truss-like structures, the longitudinal axes of all rectilinear ribs of this multitude of Foils are inclined to the longitudinal plane of the laminate. With the core is also on the side that the perforated surface layer facing, connected to a massive planar layer. .

It is a feature of the laminates according to the invention that that the perforated outer layer and the core part are integral parts of the laminate, d. H. they form in cooperation together a supporting structural element, the sound acoustically dampening and can absorb shock or mechanical shock. This result is achieved due to the fact that a predominant part of the perforations of the outer layer lies over the cavities of the core part and the core part is squeezable. This means that the perforations the outer layer are located via pneumatically connected cavities or channels in the core part and form holes, which are acoustically active in suppressing sound. These acoustically active channels extend from the surface the outer layer to the bottom of the cavities in the

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Kernte! 1. These channels of the core portion are also connected to other adjacent channels of the core portion with the opposite angle, thereby providing a tortuous path, I reproduce the sound waves in the s _(. In this feature is in addition to the other features of the Zusammeridrückbarkeit or absorption of mechanical energy, the special feature of laminates according to the invention.

Since the outer layers of the laminates according to the invention are made entirely of metal or plastic or of mixtures thereof can exist, there are some special configurations. For example, a laminate with an opaque perforated outer layer made of metal or plastic and a transparent continuous planar layer will. Furthermore, the surface of the perforated outer layer can be smooth, striped, roughened, etc., or designed in some other way be, for example by cutting, pressing, embossing, etc., in order to create an aesthetic appearance of their surface .

Excellent results are obtained by using a combination of the perforated metal or plastic outer layer and the truss-like core part, which are bonded together with or without an adhesive. Preferred adhesives are the polyurethane-based elastomeric adhesives, which will be described in more detail below. Epoxy, epoxy-polyamide, epoxy-phenolic, polyimide construction adhesives, etc. have also been found to be effective in making the laminates of the invention. The use of such perforated layers, core parts and adhesives gives excellent laminates, the adhesive content of which is generally less than 10% of the total weight of the laminate. As mentioned, it is not necessary to use an adhesive to produce the laminates according to the invention. If a perforated plastic layer

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and a planar plastic sheet can be used in a configuration in which they are on opposite sides of the core part are arranged, they can thus without the use of an adhesive, for example by hot melting and / or union under pressure. When facings, cores and massive planar layers of metal are used, the assembly can be joined together by resistance welding or soldering. Such methods are well known to the person skilled in the art and therefore do not need to be explained in more detail.

Many types of metals can be used to form the laminates of the present invention, for the metals such as corrosion-resistant steel, aluminum, and carbon steel are exemplary. Zinc, gold, galvanized carbon steel, aluminum-coated carbon steel, magnesium, copper, brass, refractory metals such as titanium, Lead, winding, silver, nickel alloys and the like can also be used as a cover layer, planar layer or core part of the new laminates can be used in the context of the invention. If the laminate is only made of metal, you can its individual components consist of the same or different metals.

In general, any polymeric material can be used for the planar solid layer or the perforated surface layer of the Laminates according to the invention are used, the individual polymers depending on the type of laminate to be produced be selected accordingly.

Examples of suitable materials include olefin polymers such as polyethylene, including polyethylene

high density, polypropylene, polyvinyl halides such as polyvinyl chloride, polyvinylidene halides

de such as polyvinylidene fluoride, polyethylene glycol terephthalate,

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"Nylon" resins, d. H. Adipic acid-polyalkyleneamine reaction products, Polycarbonates; d. H. Phosgene-polyhydroxyaryl reaction products, polyurethanes, d. H. Isocyanate reaction products based on polyether or polyester, polyvinyl acetate, polyvinyl butyral, butadiene copolymers, the polystyrenes, d. H. Polystyrene itself, polymethylstyrene, cellulose polymers such as cellulose acetate and cellulose butyrate, acrylate and methacrylate homopolymers and copolymers such as polymethyl methacrylate, polyethyl acrylate, methyl methacrylate-ethyl acrylate copolymers, the so-called "impact polymers", d. H. Rubber-polymer mixtures such as mixtures of polystyrene with 5 to 10% butadiene-styrene, polyacrylonitrile with 5 to 27% butadiene-styrene, methyl methacrylate polymers with 20 to 50% grafted Polybutadiene, thermosetting melamine-formaldehyde or phenolic resins, polysulfones, polymer blends, etc.

As mentioned above, the main features of the laminates of the invention are their unusual soundproofing properties in combination with mechanical energy absorption. Your ability to transmit acoustic Containing energy is even more astonishing when you consider that the laminates have soundproofing values that are better than the theoretical maximum for solid metal plates of the same weight.

The laminates of the invention also have the advantage that they can be stored for over 6 months at 82 ° C or above (depending on the adhesive used in the metal laminate) without stripping, increasing their commercial value to retailers and wholesalers be able to keep a sufficient supply of the laminates ready. Some laminates can also be used under cryogenic conditions, since there is no stripping of processed structures of the laminate at such low temperatures as -196 ^0C.

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Any known method can be used to produce the laminates according to the invention. For example, when solvent-based adhesives are used, the laminates of the present invention can be made by coating the sides of the layers to be bonded to the core with an adhesive, evaporating the solvent, and pressing the layers together to form the laminate. During the curing stage, the solvent in the adhesive can be ^{evaporated at 70 to 120 °} C., and the adhesive can then be ^{cured at 110 to 160 °} C. for 2 to 3 minutes. The layers are then reacted with 0.7 to 7 kg / cm - 8 pressed together and cured to 16 hours at 140 to 150 ⁰ C (10 100 psi). If adhesives curing at room temperature are used, the heat-curing step can be omitted. The adhesives can also be used as solvent-free systems that do not require an evaporation stage prior to curing. The laminates can be produced in a continuous process, in which rolls made of metal or plastic are continuously coated with adhesive and fed as a sandwich structure with the core to evaporation (if necessary), hardening and cutting zones, or they can be produced in batches, with the layers individually, For example, by spraying, covered with adhesive, put together to form a sandwich structure with the core and connected to one another by the action of heat and pressure. The only critical limitation on the application of the adhesive or heat is that the adhesive or plastic must not clog or fill the cavities in the core part or the perforations in the outer layer, since a complete blockage of air flow in the cavities or perforations through the Adhesive would significantly affect the properties of the laminate obtained. The adhesive must therefore be applied with care, and it is therefore preferred to apply the adhesive thinly to the perforated outer layer and / or continuous planar layer and thereby insert it

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To minimize the flow of the adhesive into the perforations in the cover layer or cavities in the core during curing. However, a very small amount of adhesive can be tolerated in the cavities or perforations of the facing or core. Alternatively, the adhesive _; are advantageously applied at a distance from the perforations or cavities of the perforated layer around this during the layer formation step, so that the pressure exerted on the laminate does not cause the adhesive to flow in.

On the other hand, it can be advantageous to use the holes or cavities with an air-permeable, acoustically active material, for example glass wool, foamed rubber and the like, to fill. The perforations or hollows of the perforated Outer layer can be round, square, slit-shaped, oval, rectangular, diamond-shaped, star-shaped or any be designed holes. There are no particular advantages or disadvantages to using a particular form Episode.

The terms "perforations", "cavities", etc. are understood here to mean all such perforations, which can be produced by slotting, punching, punch rolling, drilling or pressing.

The particular shape of the perforations in the outside is not critical, but it has been found that the open area in the perforated outer layer must be 5 to 50 and preferably about 15 to about 45% so that optimum sound insulation properties can be achieved.

As mentioned, the size of the perforations is not critical. The holes should have a size from about 0.25 mm (0.010 ") to about 12.7 mm (0.50") at their smallest diameter, ie the diameter of an inscribed circle,

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that touches a large number of points on the inside of the shape in question.

The core part of the laminates according to the invention can a thickness of about 3.18 to 305 mm (0.125-12 ") and preferably 6.35 to 50.8 mm (0.25-2.0 ") while the thickness of the perforated outer layer and the continuous planar layer from about 0.025 mm to 6.35 mm (1-250 mil) can range. The core part is preferably always thicker than the perforated outer layer.

The core parts of the laminates according to the invention are known commercially available truss-like metal components. They are next to method of making them in U.S. Patent 3,096,053.

These truss-like parts consist of layered ribbed foils in which the ribs of each foil are parallel are arranged to each other and generally have a flat, rigid, slightly inclined side section and uniform Have shape and size. The laminates are face to face with the ribs adjacent Films connected, which are inclined opposite to each other at an angle of 10 to 90 °. The crossed over Ribs of adjacent foils form an X-truss configuration, which is a load-bearing structure when pressure is applied to its open sides, but when applied is compressible by pressure on its closed sides.

The foils range in thickness from about 0.025 to 0.15 mm (0.001-0.006 "). The ribs of each individual foil preferably have a height of 2.38 mm (3/32 ") above midpoints of rib widths of 7.9-4 mm (5/16"), suitably however, heights range from about 1.59 to 4.76 mm (1/16 - 3/16 ") and widths of 3.17 to 12.7 mm (1/8 - 1/2").

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A core of the desired size is assembled from a sufficient number of foils, with the rib surfaces of all films are generally coated with a suitable adhesive. The foils can then pass through Heat and pressure are combined. After the adhesive has hardened, there is due to the opposite Angular arrangement of ribs of adjacent foils, the cross-section of the core material from a multitude-of to one another connected truss components with an X shape, so that there is a truss grid construction. In particular In cases where a construction with high temperature resistance is desired, the truss-like Structure by joining the foils or sheet metal strips in the desired arrangement by point or Resistance welding or soldering processes are produced.

The core parts can be made of metals, of which the above are exemplary. Paper, for example with phenolic resin impregnated kraft paper, polyimide resin impregnated kraft paper, etc., fabrics such as phenolic resin impregnated glass fabric, nylon fabric impregnated with polyimide resin, or a rigid load-bearing plastic, for Example polyvinyl halides such as polyvinyl chloride, "impact-resistant polymers", examples of which are given above *, and the like.

The adhesive layer, if used, is said to have a thickness in the range of about 0.013 to 0.51 mm (0.5 to 20 mils). Thicker layers are unnecessary and sometimes because of the difficulty of filling the perforations of the outer layer and the voids of the load-bearing Partly by the adhesive to prevent detrimental, but need not be excluded if they are for one specific use are required, especially if a vibration-damped, thermal and electrical insulating laminate is desired.

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As mentioned above, in general, any high strength adhesive material can be used as a binder for production of the laminates according to the invention can be used. to Suitable adhesives include, for example, adhesives based on polyurethane resin, silicone rubbers, polysulphides, Epoxy resin polysulphide mixtures, hydrocarbon rubbers, for example adhesives based on butyl rubber, Acrylic rubbers such as nitrile rubbers, for example those made of acrylonitrile, polyethylene or polypropylene (modified with rubber), epoxy-polyamide adhesives, Epoxy phenolic adhesives, nitrile epoxy adhesives, Polyimide adhesives, polybenzimidazole adhesives, and the like. Particularly advantageous adhesives are those that have a dynamic glass transition temperature, which is practically at or below the temperature at which the adhesive is ultimately to be used, and a dynamic glass transition frequency at the application temperature at or above the frequency value that the laminate has is ultimately exposed in use. These phenomena are detailed in an article by A. F. Lewis et al., Proc. Fourth Int. Congress on Rheol. Part 2, p. 505, 1965. Further examples for suitable adhesives, see U.S. Patents 2,610,910, 2,400,612, 2,514,427, 2,581,920, 2,673,845, 2,684,361,

2,879,252, 2,918,442, 2,920,990 and 2,977,273. To connect the laminate layers, two or more various adhesives can be used, d. H. for each layer of adhesive.

Other adhesives that can be used to produce the laminates of the invention are those that in at least one of U.S. Patents 3,391,054, 3,309,261 and

3 290 208 are explained in more detail.

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These adhesives consist of the following components:

(A) a polyurethane resin,

(B) a diamine curing agent and

(C) a diglycidyl ester, a diglycidyl ether, a monoethylenically unsaturated monoglycidyl ether or a monoethylenically unsaturated one Monoglycidyl ester or

(D) an aminosilane as a replacement for or in addition to (C) or

(E) an epoxysilane as a substitute for (D) and in addition to (C) or

(F) a polyethylenically unsaturated compound in addition to (A), (B), (C) and (E).

As indicated above, the preferred adhesive used to make laminates of the present invention is of (a) a polyurethane prepolymer, (b) a diamine curing agent, (c) a trifunctional alcohol amine and (d) a glycidoxyalkyltrialkoxysilane in certain proportions.

The polyurethanes

For the preparation of the preferred for the purposes of the invention Adhesives can be any polyester-based polyurethane resin or polyether base can be used. To the reactive organic polyfunctional polyols used in the manufacture of a class of polyurethane resins for use in the present invention

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Purposes by reacting with a suitable isocyanate compound are used, the polyalkylene ether, thioether and ether thioether glycols belong to the general one formula

CD HX- (RX) _n -H,

where R is identical or different alkylene radicals with up to about 10 carbon atoms, X is oxygen or sulfur ' and η means an integer with a sufficiently large value, so that the molecular weight of the polyalkylene ether, thioether or ether thioether glycol is at least about 500, for example about 500 to about 10,000. The polyalkylene ether glycols falling under this general formula are preferred, for example polyethylene glycols, polypropylene glycols, Polybutylene glycols, polytetramethylene glycols, Polyhexamethylene glycols and the like, for example by acid-catalyzed condensation of the corresponding monomeric glycols or by condensation of lower alkylene oxides, for example ethylene oxide, propylene oxide and the like, either with themselves or with glycols such as ethylene glycol, propylene glycol, and the like can be obtained.

Polyalkylenearylene ether, thioether and ether thioether glycols, which also have molecular weights in the range of have about 500 to 10 000, but differ from the polyalkylene glycols described above in that that they are arylene radicals, for example phenylene, naphthylene or anthrylene groups, which are either unsubstituted or may be substituted, for example by alkyl or aryl groups and the like, in place of a portion of the Alkylene radicals of the polyalkylene glycols can also be used. Polyalkylenearylene glycols des the type commonly used for this purpose usually contain at least one alkylene ether group with one Molecular weight of about 500 per arylene group present.

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Virtually linear polyesters which contain a large number of isocyanate-reactive hydroxyl groups form a further class of reactive organic polyfunctional polyols which can be used for the preparation of polyurethane resins suitable for the purposes of the invention. While the preparation of polyesters suitable for this purpose is well described in the literature and does not form part of the invention, it is recalled that polyesters of this type are produced by the condensation of a polyhydric alcohol, generally a saturated aliphatic diol such as ethylene glycol 1,2- propanediol, 1,3-propanediol , 1,3-butanediol, 1,4-butanediol, 1,2- pentanediol, 1,5-pentanediol, 1,3-hexanediol, 1,6-hexanediol, diethylene glycol , Dipropylene glycol, triethylene glycol, tetraethylene glycol and the like and mixtures of such diols with one another or with smaller amounts of polyols with more than two hydroxyl groups, preferably saturated aliphatic polyols such as glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol and the like, with a polycarboxylic acid or a polycarboxylic acid generally a dicarboxylic acid or a corresponding anhydride, which are either saturated or only benzenoid unsaturated Contain residues, for example oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, malic acid, phthalic acid, cyclohexanedicarboxylic acid or endomethylenetetrahydrophthalic acid and the like, as well as their isomers, homologues and other substituted derivatives with, for example, their isomers, homologues and other substituted derivatives Acids can be prepared with each other and with unsaturated dicarboxylic acids or their anhydrides such as maleic acid, fumaric acid, citraconre, itaconic acid and the like, as well as with polycarboxylic acids containing three or more carboxyl groups, for example aconitic acid and the like .

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The substantially linear polyesters commonly used in the manufacture of polyurethane resins preferably have Molecular weights ranging from about 750 to about 30000. In addition, they are generally proportionate lower acid numbers, for example acid numbers, which are not appreciably above about 60 and preferably as low as can only be achieved in practice, for example 1 or less. Accordingly, they generally show relatively high hydroxyl numbers, for example of about 30 to 700. To produce these polyesters, an excess of polyol over polycarboxylic acid is generally used used to ensure that the virtually linear polyester chains obtained have a sufficient Contain number of reactive hydroxyl groups.

Another class of suitable organic polyfunctional polyols are polyalkylene ether polyols, the contain more than two reactive hydroxyl groups, for example polyalkylene ether triols, tetrols and the like, which, for example, by reacting polyols such as glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, Dipentaerythritol, sorbitol and the like with lower alkylene oxides such as ethylene oxide, propylene oxide and the like can be produced.

Nitrogen-containing polyfunctional polyols can also be used as polyol reactants. Such substances include the polyester amides commonly used in the manufacture of polyurethane resins, d. H. those with molecular weights ranging from about 750 to about 3000, acid numbers that of about 60 as a maximum to the lowest practically achievable acid numbers, for example 1 or less, and hydroxyl numbers in the range from about 30 to about 700, and also high molecular weight polyamino alcohols, for example hydroxypropylated ones Alkylenediamines of the general formula

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162984

(II) (HOH ₆ C ₃ ) ₂ N-R ¹ -H (C ₃ H ₆ OH) ₂ ,

wherein R ¹ denotes an alkylene radical having 2 to 6 carbon atoms, of which N, N, N ¹ , N'-tetrakis (2-hydroxypropyl) ethylenediamine is a representative example, as well as higher analogs thereof, for example hydroxypropylated polyalkylene polyamines of the general formula

(III) (HOH ^ Cj) ₀ N-R ¹ -N-R'-N (C-.H, 0H) _o ,

Ό 3 Z 3 Ό Ζ

C, H, _C OH

§ ³⁶

wherein R ^{1 is} as defined above (see US Pat. No. 2,697,118).

As is apparent to the person skilled in the art, mixtures of the various reactive organic compounds described above can also be used between polyfunctional polyols used for the production of polyurethane resins for the purposes of the invention will.

As with the polyol reactant, various organic compounds can be used to make the polyurethane resins Polyisocyanates are used, including, for example, aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 4-t-buty1-m-phenylene diisocyanate, 4-methoxy-ra-phenylene diisocyanate, 4-phenoxy-m-phenylene diisocyanate, 4-chloro-m-phenylene diisocyanate, toluylene diisocyanate (either as a mixture of isomers, for example the commercially available mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate, or in Form of the individual isomers), m-xylene diisocyanate, p-xylene diisocyanate, Cumene-2,4-diisocyanate, durene diisocyanate, 1,4-naphthylene diisocyanate, 1,5-naphthylene diisocyanate, 1,8-naphthylene diisocyanate, 2,6-naphthylene diisocyanate, 1,5-tetrahydronapthylene diisocyanate, ρ, ρ '-diphenylene diisocyanate, Diphenylmethane-4,4'-diisocyanate, 2,4-diphenyl-

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. - 19 -

hexane-lrö-diisocyanate, "ditoluylene diisocyanate"

(3,3 · -Dimethyl-4,4'-biphenylene diisocyanate), "Dianisidine diisocyanate" (3,3'-dimethoxy-4,4'-biphenylene diisocyanate), and polymethylene polyisocyanates in general

formula

(IV)

N = C = O

where m is an integer between 0 and about 5, aliphatic diisocyanates such as methylene diisocyanate, ethylene diisocyanate, the tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and decamethylene-omega, omega'-diisocyanates, 2-chlorotrimethylene diisocyanate, 2,3-dimethyltetramethylene diisocyanate and triisocyanates and higher isocyanates such as benzene-1,3,5-triisocyanate, toluylene-2,4,6-triisocyanate _f diphenyl-2,4,4'-triisoeyanate , triphenylmethane-4, 4 ', 4 "-triisocyanate and the like belong · Mixtures of two or more such organic polyisocyanates can also be used to prepare the polyurethane resins by reaction with the ethers and esters described above using known methods (cf., for example, US Pat. No. 2,729,618 and 3,016 364) can be used.

These known polyurethane production processes include, for example, the so-called "prepolymer" technology, commonly used in the manufacture of polyurethane resins. According to this method, polyol and Polyisocyanate under practically anhydrous conditions, d. H. usually no more than about 0.2 weight percent Water based on the total weight of the mixture is present, usually using a molar amount

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Excess of the polyisocyanate is mixed over the polyol, the mixture is reacted at a temperature in the range from about room temperature to about 100 ^° C. for about 20 minutes to about 8 hours, and the resulting "prepolymer" is then heated to a temperature of about room temperature to about 60 C cooled.

In addition, particulate or fibrous fillers, for example chopped alpha-cellulose, asbestos or Glass fibers, common flame retardant additives, for Example phosphates such as triphenyl phosphate, tricresyl " phosphate, tris (2,3-dibromopropyl) phosphate or tris (ßchlorethyl) phosphate, Dyes or pigments, for example silica pigments, stabilizers and the like can be added to the polyurethane resins.

Modifications and alterations made to common polyurethane reaction mixtures to produce resins with varying degrees of flexibility, stiffness and other properties are so well known that brief references will suffice here. In addition to the above-mentioned embodiments, d. H. the use of practically linear polyesters and polyester amides with certain molecular weights, acid numbers and hydroxyl numbers and the variation in the molar ratio from polyisocyanate to polyol, numerous other modifications, for example the use of trifunctional or higher functional monomeric polyols or polycarboxylic acids to produce the polyol reactant, the use of trifunctional or higher functional polyisocyanates and the like in the literature to achieve these results. All of these modifications can be made in conjunction with others Modifications indicated in known processes for the production of polyurethane resins, those according to the invention Purposes.

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Jie diamine curing agent

For the purposes of the present invention, any desired hardening agent may be incorporated into the polyurethane resins, including those in prepolymer form obtained as described above. To those used Diarainnärtungsraitteln include, for example, the alkyl and Aryldiaiidne such as hexamethylene diamine, 4,4'-Diarcinoaiphenylmethan, benzidine and its derivatives, p-phenylenediamine, 4,4 'diamino-3,3'-dimethyldiphenylmethane, 4, ^4? -Diamino -3, 3'-diraethoxydiphenylmethane, 3,3'-dichlorodiaminodiphenylmethane, etc. A preferred group of compounds is formed by the diaminodihalodiaryls, of which 2,2'-methylene-bis-2-orthochloroaniline is an example. The diamines are used in equivalent amounts of 45 to 99% and preferably about 50 to about 90%, based on the available free NCO content of the polyurethane prepolymer, is introduced into the urethane prepolymer syrup or added to the adhesive itself.

the Kpoxysilanes

The epoxysilanes can be added to the compositions in amounts from 0.1 to 15.0%, and preferably from about 0.5 to about 10.0%, based on the total weight of the adhesive composition. The epoxysilane can be added at any time, ie before, together with or after the curing agents. However, the epoxysilane cannot be added after the composition has cured.

For the new adhesive compositions according to the invention jeles epoxysilane can be used. Exemplary and preferred are the glycidoxyalkyltrialkoxysilanes such as

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gamma-glycidoxypropyltrimethoxysilane and beta-3,4- (epoxycyclohexyl) ethyltrii.iethoxysilane. Other known epoxysilanes can also be used for Examples are those described in US Pat. No. 2,946,701 and Gß-PS 834,326.

The epoxysilanes can be prepared by any known method. In general, after one such method reacted a suitably substituted silane with an unsaturated glycidyl ether. at for example, triuethoxysilane is used with allyl glycidyl ether reacted in the presence of a platinum catalyst at elevated temperatures to gamma-glycidoxypropyltriraethoxysilane.

The trifunctional alcohol amines

As indicated above, it has been found that the introduction of a trifunctional alcohol amine as a curing agent in the adhesive compositions described herein in connection with the diamine hardening agents results in an adhesive which not only has a high Resistance to lift-off in the case of metal laminates produced with it retains, but leads to the vibration damping of the laminates obtained is unexpectedly considerably improved.

The trifunctional alcohol amines can be included in the adhesive composition in amounts of 55.0 to 1.0 percent by weight and preferably about 50.0 to about 10.0 percent by weight, based on the content of the polyurethane prepolymer available free JCO, similar to the Diamine can be the alcohol amine in the urethane prepolymer syrup introduced or the adhesive composition even be added. The alcohol amines are common

BATH 209826/0996

known and include, for example, triisopropanolamine, i'riäthanolainin, triisobutanolamine, trihyclroxypyridine, 2,2 '- ■ (p-hydroxyphenylimino) diethanol and the like.

Other additives

If desired, various further additives can be used as reactive constituents in the adhesive compositions according to the invention be introduced. Examples include diglycidyl ethers, diglycidyl esters, and monoethylenically unsaturated monoglycidyl ethers and monoethylenically unsaturated monoglycidyl esters for producing adhesive compositions according to the invention advantageous. Individual examples of such substances are glycidyl methacrylate / glycidyl acrylate, allyl glycidyl ether, Diglycidyl phthalate, glycidyl benzyl acrylamide, the diglycidyl ether of 2,2-bis (p-hydroxyphenyl) propane and other aryl or alkyl diglycidyl esters known to the person skilled in the art and ethers and mono-ethylenically unsaturated monoglycidyl ethers and esters. The diglycidyl ethers, diglycidyl esters, monoethylenically unsaturated monoglycidyl esters and raonoäthylenisch unsaturated honey glycidyl ethers in amounts of about 5.0 to 25.0 percent by weight, based based on the total weight of the adhesive mass will. When using these Glycidy! Compounds for Preparation of adhesive compounds should also contain about 0.01 to about 2.0 percent by weight of a peroxy catalyst, based on the total weight of the composition, to accelerate its implementation. Suitable catalysts for this are, for example, 2,5-uiraethyl-2,5-di- (t-butylperoxy) -hexane, t-butyl perbenzoate, Dicurayl peroxide, benzoyl peroxide, azobisisobutyronitrile, the diacyl peroxides such as diethyl peroxide, the alkyl hydroperoxides like t.-duty! hydroperoxide, syinnetric diacyl peroxides such as acetyl peroxide and the like.

209826/0996

The manner in which the ingredients of the compositions are combined is not critical, and within the scope of the invention they can be added in any combination or individually. However, it was found that it is generally preferable to use a premix of the diamine curing agent, the epoxysilane and the polyfunctional alcohol amine with or without the mono- or diglycidyl ether or ester and catalyst prepare and add the polyurethane prepolymer to this mixture at room temperature. Such a one However, the method of operation is not essential, and in the context of the invention, the epoxysilane can also be used first mixed with the polyurethane prepolymer and then the curing agents added, or the polyurethane can first the curing agents and then the epoxysilane are added.

Before applying the glue to the metal, this should be Metal preferably be chemically pure. This can be done by treating the metal with hot or aqueous alkali Acid solution can be achieved. The adhesive is preferably used as a 40 to 50 percent solution in a solvent such as methyl ethyl ketone and can be applied to the Metal by painting, roller coating, rotor coating or spray methods and the like can be applied.

Through the following examples in which all parts and percentages are by weight if nothing otherwise indicated, the invention is explained in more detail.

example 1

Lin laminate is made by joining with an adhesive produced as follows: 80 parts of gamma-glycidoxypropyltrimethoxysilane are made with 114 parts

2 09826/0996

finely powdered 4,4'-methylenebis-2-ortho-chloroaniline and 18 parts of triisopropanolamine are added to a suitable vessel. 120 parts of a commercially available polyester-based polyurethane prepolymer (90/10 ethylene glycol / propylene glycol adipate; IICO content 4.2%) are then added to the mixture obtained with stirring. The mass obtained is mixed into a smooth paste for the application to produce the laminate. The laminate is ^{cured at 150 °} C. and 4.9 kg / cm (70 psi) and consists in the order given of (1) an outer perforated aluminum foil with a thickness of 0.51 mm (0.020 "), perforations with diameters of 0.51 mm

2 (0.020 ") and staggered centers, 80 holes per cm

(520 / sqare inch) and an open area of 20%, (2) a truss-like core part with a thickness of 12.7 mm (0.50 ") and 3.18 mm (1/8") cell size made from 0.064 mm (0.0025 ") thick foils manufactured as described in US-PS 3 096 053, and (3) a solid aluminum foil with a thickness 0.64 mm (0.025 ") together.

The laminate produced is then tested for its sound absorption capacity according to ASTM test method C-384-58. The results are shown in Table I. The table also shows comparative values for a similar one Laminate with a honeycomb metal core with dimensions similar to the lattice-like core of the laminate from example 1 (all other variables remain practically the same).

20S326 / 0996

Tabel Comparison of the acoustic absorption coefficients

Frequency (Hz) Laminate from
example 1 viabenkern-
laminate 500 O, O8 O, O4 800 O, O6 O, O2 1000 O, O4 O 04 1250 0.04 O, O4 1600 0.13 0.09 2000 0.12 0.11 2500 0.2O O, 2O 3150 O, 33 O, 25 4000 0.40 0.27 5000 0.55 0.33

20982S / 0996

Example 2

When a commercially available glassy brittle polyimide adhesive is used in place of the adhesive described in Example 1, while all other variables remain the same, a sound deadening box made from the laminate obtained produces a similar result achieved.

Example 3

A laminate has the same lattice-like core and the same solid aluminum foil as in Example 1 is made, with the exception that the perforated cover layer is made of a polyvinyl chloride film with a thickness 4.8 mm (0.190 ") and 4.76 mm (3/16") diameter holes with spaced centers of 9.53 mm (3/8 "). The sound absorption capacity of the laminate obtained is compared to a similar honeycomb core laminate (all other variables remain the same) even more pronounced. In the Results obtained in a manner similar to the results of Table I are shown in Table II below.

209826/0996

Table II

Comparison of the acoustic absorption coefficients

Laminate of honeycomb core frequency (Hz) Example 3 laminate

500 800

ψ 1000

1250 1600 2000 2500 3150 4000 5000

0.04 0.04 0.04 0.04 0.05 0.05 0.06 0.05 0.10 0.11 0.19 0.11 0.25 0.15 0.32 0.15 0.56 0.28 0.36 0.12

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Example 4

A 12.7 mm (1/2 ") thick layer of a truss-type Core made as in Example 1, but with an open cell size of 1.59 mm (1/16 "), which is made with channels made of 0.051 mm (0.002 ") aluminum foil that are connected at a 45 angle is covered with a 0.76 mm (0.030 ") thick solid planar sheet of aluminized cold rolled steel and a skin or cover layer of 0.61 mm (0.024 ") thick mild steel with perforations with a diameter of 4.76 mm (3/16 ") and centers 11.11 mm (7/16") apart with an open area of 13%. As in example 1 measured acoustic absorption values are given in Table III below. The excellent Sound absorption values in the range from 1000 to 5000 Hertz are for noise insulation and absorption in the so-called Speaking range of importance. The human ear is most sensitive in this frequency range.

Table III

Coefficient of acoustic absorption frequency (CPS) of the laminate of Example 4

200 0.04

400 0.07

500 0.10

630 0.16

1000 0.18

1250 0.31

1600 0.56

2000 0.89

2500 0.98

3150 0.85

4000 0.92

5000 0.66

The procedure of Example 1 is repeated again, with the exception that the perforated film and the solid planar film made of polyethylene glycol terephthalate and the framework-like core made of kraft paper impregnated with phenolic resin exist. It becomes an excellent laminate with properties similar to the laminate of Example 1 received.

Example 6

The procedure of Example 1 is with the exception repeats that a transparent impact-resistant layer is used for the perforated front side and the solid planar layer Acrylic polymer is used. It becomes a transparent laminate with properties similar to the laminate obtained from Example 1.

Example 7

The procedure of Example 4 is repeated with the exception that the solid aluminized steel layer and the perforated mild steel layer is connected to the lattice-like core part by spot soldering. It will again a laminate with excellent sound absorption properties obtain.

Example 8

3 parts of gamma-glycidoxypropyltrimethoxysilane are with 11.4 parts of finely powdered 4,4'-methylenebis-2-orthochloroaniline and 1.8 parts of triisopropanolamine are added to a suitable vessel. To the mixture obtained then 120 parts of a commercially available one

209626/0996

Polyurethane prepolymers based on polyester (90/10 ethylene glycol / propylene glycol adipate; NCO content 4.2%) were added with stirring. The resulting mass is mixed to form a smooth paste and applied to two aluminum plates with the dimensions 15 cm 28 cm (6 'χ 11 "). The stack is placed in a press and at a pressure of 12 kg / cm (17Ο psi) one hour at 105 ⁰ C, one
heated to 158 ^° C. for the ^{second hour and to 80 °} C. for 15 hours.

The peel strength of the laminate obtained at room temperature is 4, Vibration damping 0.05.

Room temperature is 4.43 kg / cm (63 psi) and the

Example 9

The procedure of Example 8 is repeated except that an equivalent amount of one is commercially available available polyurethane prepolymers based on polyether (Polytetramethylene type) is used. The adhesive produced in this way is used to bond two panels together.

2
bound. The lift-off strength is 4.29 kg / cm (61 psi)

and the vibration damping 0.04.

Example 10

The procedure of Example 3 is repeated with the exception that 15.0 parts of glycidyl methacrylate and 0.1 part of 2,5-dimethyl-2,5-di (t-butylperoxy) -n-hexane are added to the hardener mixture and the
Amount of silane is reduced to 5.0 parts. The peel strength of the laminate produced is 5.27 kg / cm (75 psi) and the vibration damping is 0.04.

209826/0996

Example 11

Using the amounts given in Examples 8 and 9, an adhesive is prepared which consists of two parts, each of which is dissolved in methyl ethyl ketone. One part contains the polyurethane prepolymer and the second part the 4,4'-methylenebis-2-orthochloroaniline, triisopropanolamine and gamma-glycidoxypropyltrimethoxysilane. The two parts can be combined before use and applied to the substrate by brush, roller or runner coating or by spraying. To illustrate this type of order two aluminum plates with the blended product being sprayed, and the coating is pre-cured for 30 to 60 minutes in an oven at 110 ⁰ C. The thickness of the precured coating is 20 to 30% of the thickness of the substrate. Another layer of adhesive is then applied to the coating, and the plates are ^{held at 110 °} C. for 2 to 10 minutes in order to evaporate the solvent and develop the adhesive. The plates are then brought together and placed in a press at 110 ^° C. and 7 kg / cm (100 psi) for 30 to 60 minutes. (Alternatively, the stack can pass through a nip at a pressure between 0.7 to ^s

2
Be performed), the final curing is carried out for 3 hours at 110 ⁰ C and 3 hours at 150 ⁰ C - 14 kg / cm (200 psi 10).. The lift-off resistance and vibration damping of the laminate produced are excellent.

Following the procedure of Examples 8-11, various commercially available polyurethane prepolymers are made with various diglycidyl esters and ethers and monoethylenically unsaturated monoglycidyl esters and -ether, various hardeners and various epoxysilanes. The results are shown in Table IV.

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Tabel

IV

at
game PU from
example Glycidyl
ester;
Parts Diamine
Hardening
middle Alcohol-
amine
Parts Epoxysilane,
kg / cm,
Parts original
Lift-off
speed at 25 ⁰ C,
(ppi) Vibration
damping 12th 1 —— MOCA-7.6 TIPA-3.6 GPTS-6.0 62 0.069 13th 2 MOCA-9.6 TIPA-3.0 GPTS-8.0 55 0.138 14th 1 MOCA-11.4 TIPA-1.3 GPTS-8.0 63 0.050 NJI
O
CO 15th
16 1
2 GMA; 15.0
GMA; 15.0 MOCA-11.4
MOCA-10.4 TIPA-1.8
TIPA-2.6 GPTS-5.0
GPTS-8.0 75
42 0.040
0.040 00 17th 1 MOCA-11.4 TIPA-1.8 GPTS-10.0 60 0.138 OJ CD 18th 2 MOCA-10.4 TIPA-2.6 GPTS-8.0 38 0.173 O
co 19th 1 GMA; 7.0 MOCA-7.6 TIPA-3.6 GPTS-6, 0 40 0.050 co
o> 20th 1 GMA; 35, O MOCA-7.6 TIPA-3.6 GPTS-6.0 52 0.040 21st 1 MOCA-15.2 TIPA-0.3 GPTS-8.0 83 0.042 22nd 1 MOCA-11.4 TIPA-1.8 GPTS-20.0 50 0.150 Ver
the same. A-2 GMA; 15.2 MOCA-15.2 GPTS-1.0 80 0.0198 Ver
same. BI GMA; 16.0 MOCA-16.0 mmmmwrn GPTS-1.0 96 0.018 CJ)

Explanation to Table IV:

GMA - glycidyl methacrylate

MOCA »4,4'-methylene-bis-2-ortho-chloroaniline

GPTS «gamma-glycidoxypropyltrimethoxysilane

_Μ PU w polyurethane

as TIPA * triisopropanolamine

μ 1. ■ measured as log. Decrement according to the equation

⁰⁰ Δ * h log τΓ? where Ao * amplitude at the beginning

θ) ^Ί η An

and An amplitude according to η Cyden.

Claims (4)

Claims Sound-absorbing layer structure made up of two outer layers and a core part, characterized in that that the core part of a plurality of straight ribbed thin sheets of construction material consists, which are connected to each other on all contact surfaces with front to front and their ribs are inclined at an angle and cross the ribs of adjacent foils, creating the crossed ribs Form rigid truss-like structures, with the longitudinal axes of all rectilinear ribs of the plurality of Films are inclined to the longitudinal plane of the laminate, and that with one of the sides of the core part massive outer layer and with the side of the core part which is opposite to the massive outer layer, one perforated outer layer with an open area of 5 to 50% is connected. 2. Laminate according to claim 1, characterized in that the outer layers by an adhesive are connected to the core part. 3. Laminate according to claim 2, characterized in that the adhesive consists of a uniform mixture from (a) a polyurethane prepolymer, (b) 45 to 99% of the stoichiometrically equivalent amount of a diamine curing agent, based on the content of (a) free -LSiCO, (c) 1 to 55% of the stoichiometrically equivalent Amount of a trifunctional alcohol amine, based on äen content of (a) free -NCO, and (d) 0.1 to 15 percent by weight of a glycidoxyalkyltrialkoxysilane, based on the total weight of the adhesive mass 209826/0996 4. The adhesive of a uniform mixture of a polyurethane prepolymer, a Diaminhärtungsmittels and a Glycidoxyalkyltrialkoxysilans, characterized in that up to 55% of the stoichiometrically equivalent amount, it contains a trifunctional alcohol amine, based on the content of the polyurethane prepolymer of free -WCO 1. / 0996