RU2329148C2 - Polyurethane-containing multi-layer block and method to produce it - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: invention relates to multilayer blocks for manufacturing details for external parts of vehicles. The multilayer block consists of an internal layer from thermoformable polyurethane foamed plastics, paper, metal or plastic honeycombs fibrous layers furnished on both sides of the internal layer and reinforced by polyurethane. The block also includes an external layer with an A surface quality class selected from the group containing metal foil or tin, as well as compact thermoplastic plastic components from polymethylmethacrylate, acryl ether of modified styrene-acrylonitrile-terpolymer, polycarbonate, polyamide, polybutyleneterephthalate and/or polyphenyl oxide on the layer of the fibre. If necessary, the block includes a decorative layer selected from the group, containing textile substances, covered, to protect against foaming, by a film from thermoplastic polyurethane, compact or foamed polymer films, as well as evaporated of RIM-films from polyurethane on the second layer of the fibre.

EFFECT: high-quality surfaces of details for external sites of whatever vehicles with A-class surface.

2 cl, 3 ex

Description

The object of the invention are plastic containing multilayer blocks, in particular PU (polyurethane) -containing multilayer block, and a method for its preparation.

Parts for the exterior of vehicles with class A surfaces and special mechanical functions are mostly made of metal. The disadvantage in this case is the high dead weight of these parts. To the forefront as a criterion for the quality of surfaces is the well-known method of wave scanning with small values of surface waviness for long and short waves.

When using polyurethane materials, in most cases compact materials with reinforcing fillers are used in order to increase specific mechanical properties, such as, for example, bending stiffness. Such reinforced polyurethanes are already used for the manufacture of aprons, channels, templates or door ceilings and car fenders for the exterior of automobiles. The materials used are characterized by relatively high expansion parameters, that is, large linear coefficients of thermal expansion (α-coefficients), which deviate greatly from the coefficients of commonly used metals, as well as a higher density. In these products, the quality of surfaces with small values of surface waviness for long and short waves, obtained by the known method of wave scanning, comes to the fore.

In order to achieve excellent quality of surfaces with low values of surface undulation for long and short waves in this case, products, if necessary, should be subjected to surface treatment.

In order to eliminate the above drawbacks, polyurethane layered units with integrated outer layers having surface class A, with very high flexural rigidity and a small coefficient of expansion (α-factor in the range from 1 to 15 × 10 ⁶ m have been developed · K ^{- 1} · m ^-1 ), low density and high quality surfaces.

The object of the invention is thus a multilayer block of

A) the inner layer

B) fiber layers located on both sides of the inner layer and reinforced with polyurethane (P),

C) the outer layer with a class A surface quality on one fiber layer,

D) if necessary, a decorative layer on the second layer of fiber.

The object of the invention is also a one-step process for producing a multilayer block with an outer layer and, if necessary, a decorative layer to obtain the proposed multilayer blocks. For the manufacture of products with the indicated reinforcing fillers, processing methods are considered the NafpurTec, LFI / FipurTec or Interwet method and the lamination method. The multilayer material is obtained at molding temperatures of 60-140 ° C.

Polyurethane (P) is obtained by reaction

1) at least one polyol as one component with an average hydroxyl number from 300 to 700, which contains at least one short chain polyol and at least one long chain polyol, while the source polyols have a functionality of from 2 until 6,

2) at least one polyisocyanate,

3) water

4) activators,

5) stabilizers, as well as

6) if necessary, other auxiliaries, release agents and additives.

Suitable polyol as one component are polyols with at least two H atoms reactive with isocyanate groups; preferably, complex and simple polyether polyols are used.

Preferably according to the invention, multicore isocyanates of the diphenylmethanediisocyanate series (pMDI types), their prepolymers or crude MDI are used.

Water is used in amounts of 0.1-3.0, preferably 0.3-2.0, parts per 100 parts of the polyol as one composition.

For catalysis, conventional activators for chain extension and crosslinking reactions, such as amines and metal salts, are used.

As foam stabilizers are considered, first of all, polyethersiloxanes, especially water-soluble representatives. These compounds are generally constructed in such a way that the copolymer of ethylene oxide and propylene oxide is bound to the polydimethyl siloxane residue. Such foam stabilizers are described, for example, in US patents US-PS 2834748, US-PS 2917480 and US-PS 3629308. Of particular interest are polysiloxane-polyoxyalkylene copolymers, repeatedly branched by allophanate groups according to German patent application DE-OS 2558523. Suitable other organopolysiloxanes, hydroxyethylated alkyl phenols, hydroxyethylated fatty alcohols, paraffin oils, ricinoleic oil or ricinoleic acid esters, Turkish oilseed meal and peanut butter and cellular regulators such as paraffins, nye alcohols and dimethylpolysiloxanes. In addition, oligomeric polyacrylates with polyoxyalkylene and fluoroalkane residues as side groups are suitable for improving the emulsifying effect, dispersing the excipient, cell structure and / or for stabilizing them. Surfactants are usually used in amounts of from 0.01 to 5 wt. parts per 100 wt. parts of polyol.

To obtain polyurethane, other auxiliaries, release agents and additives, for example surfactants, such as emulsifiers, means for reducing flammability (flame retardants), means for the formation of crystallization centers, oxidation inhibitors, external can be added to the reaction mixture, if necessary. polymer incompatible grease and internal grease for removing the product from the mold, dyes, dispersants and pigments.

The components for the interaction are taken in such quantities that the ratio of the equivalents of the NCO groups of the polyisocyanate a) to the sum of the hydrogens active with respect to the isocyanate groups, components b) and c), and also, if necessary, e), is from 0.8: 1 to 1.4: 1, preferably from 0.9: 1 to 1.3: 1.

As the material for the inner layer A), thermoformed polyurethane foams, paper, metal or plastic honeycombs can be used,

As the fibrous material B) can be used fiberglass canvas, glass wool, combined disordered fiberglass, fiberglass fabric, chopped or ground fiberglass or mineral fibers, canvas and knitted fabrics of natural fiber, chopped natural fibers, as well as canvas, cotton and fabric based on polymer, carbon or aramid fibers, as well as mixtures thereof.

Suitable outer layers C) are metal foil or sheet metal, as well as compact thermoplastic plastic composites of PMMA (polymethylmethacrylate), ACA (modified styrene-acrylonitrile terpolymer acrylic ester), PC (polycarbonate), PA (polyamide), PBT (polybutylene terephthalate) and / or PFD (polyphenylene oxide) for external use. The outer layer can be varnished, prepared for varnishing or painted.

As a decorative layer D), textile substances can be used, which are coated with a TPU film (thermoplastic polyurethane), compact or foamed polymer films, and also sprayed films or RIM films (films obtained by injection of melt) made of polyurethane to protect against foaming.

The fibrous components of the fiber layer B) can be applied as a fabric to the inner layer A) or, in the case of chopped or ground fibers, can be introduced with the polyurethane components or over the polyurethane components (P) or sprayed.

The proposed multilayer blocks are obtained in such a way that, first, a layer of fiber B) is applied to the inner layer A) on both sides and coated with the original polyurethane components. Alternatively, a reinforcing filler may also be introduced into the polyurethane feed stream using a suitable mixing technique in the feed head. Polyurethane plastic masses can also be obtained according to methods described in the literature, for example, according to the “one-shot” method or using a prepolymer, using devices known in principle to those skilled in the art. Preferably they are obtained by the method of "one-shot".

The preform thus obtained is transferred to a mold that contains the outer layer C) and, if necessary, the decorative layer D), and by closing the mold and finally reacting the polyurethane raw materials, the preform is bonded to the outer layer C) and, if necessary, to the decorative layer D). The preform can also be made using suitable technology directly in the molded mold.

The proposed multilayer materials are characterized by low densities - in the range from about 400 to 700 kg / cm ³ , high bending stiffness - in the range from about 0.5 to 5.2 × 10 ⁷ N · mm ² and very high surface quality. In particular, they possess, in comparison with traditional plastics and metals that are used in the field of external applications, such as polycarbonate / acrylonitrile-butadiene-styrene (PC / ABS), polypropylene, Noryl ^® (a mixture of polyphenylene oxide and polyamide), exercise therapy ( sheet molded compounds) or aluminum or steel sheets, with comparable bending stiffness, with significantly lower unit surface weights.

The fields of application of the proposed multilayer materials are modules for roofs, for engine covers, luggage racks, door or floor plates in the automotive industry.

Examples

Source materials:

Polyol 1: Hydroxy number 865 polyether polyol obtained by adding propylene oxide (PO) to trimethylolpropane

Polyol 2: Polyester polyol with a hydroxyl number of 1000, obtained by adding PO to trimethylolpropane as a starter

Polyol 3: Polyester polyol with a hydroxyl number of 42, obtained by adding 86% PO and 14% EO (ethylene oxide) to propylene glycol as a starter

Polyisocyanate: MDI polymer with an isocyanate content of 31.5 wt.% (Desmodur ^® 44V20L, Bayer AG).

Stabilizer: Silicone stabilizer Polyurax ^® SR242, Osi Crompton Witco Specialties, D 60318 Frankfurt, Hum-boldstr. 12

Catalyst: The catalyst of the class Thancat ^® AN10 amines, Air Products GmbH, D-45527 Hattingen

Dye: Baydur ^® Schwarzpaste DN, Bayer AG

Polyurethane Formulation 1:

Polyol 1 30 wt. parts Polyol 2 20 wt. parts Polyol 3 33 wt. parts Catalyst 2.8 wt. parts Stabilizer 1.3 wt. parts Acetic acid 0.3 wt. parts Water 1.4 wt. parts Dye 3.3 wt. parts Polyisocyanate 140 wt. parts

The mixture of polyols 1-3 has an average hydroxyl value of 568 mg KOH / g.

Example 1

On the inner layer, a paper honeycomb type of corrugated cardboard 5/5 with a thickness of 12 mm and a surface unit weight of 960 g / cm ³ , on both sides were laid canvas chopped fiberglass (B) with a surface unit weight of 450 g / cm ³ and at room temperature by spraying, a total of 1150 g of the polyurethane composition according to formulation 1 (P) was applied. The resulting sandwich-type multilayer structure was placed in a mold in which an aluminum sheet coated with a standard varnish coating with a thickness of 0.85 mm, a density of 2640 kg / m ³ and initial stiffness was inserted into the lower part as the outer layer (C) a bend of 2.18 × 10 ⁵ N · mm ² , and to the top as a decorative layer D) is a textile decor coated to protect against foaming with a polyurethane film with a surface unit weight of about 180 g / m ² . Then the material was pressed in a mold heated to 110 ° C to a wall thickness of 11.7 mm. After pressing for 240 seconds, the mold was opened and the finished multilayer block was removed. The multilayer block had a density of 444 kg / m ³ and a bending stiffness of 5.20 × 10 ⁷ N · mm ² .

In relation to the outer layer (C) in the proposed multilayer block, the bending stiffness was increased by more than 200 times and the average density was reduced from 2640 kg / m ³ to 444 kg / m ³ .

Example 2

The preparation was carried out analogously to example 1, but at the same time, a paper honeycomb of the type 5/5 corrugated cardboard with a thickness of 5 mm and a surface unit weight of 395 g / cm ^{3 was} used as the inner layer (A), and 1000 were applied on chopped fiberglass canvases applied on both sides g polyurethane composition according to the recipe 1 (P). The thickness of the aluminum sheet used as the outer layer (C) was 0.35 mm, and the material had a density of 2540 g / cm ³ and an initial bending stiffness of 1.52 × 10 ⁴ N · mm ² . As a decorative material (D), foaming-protected textiles with a surface unit weight of 180 g / cm ^{3 were used} . The 4.9 mm thick multilayer block obtained after pressing at 110 ° C had a density of 654 kg / m ³ and a bending stiffness of 8.56 × 10 ⁶ N · mm ² . The initial bending stiffness of the outer layer (C) is increased 560 times.

Example 3

The preparation was carried out analogously to example 1, but at the same time, paper honeycomb type corrugated cardboard 5/5 with a thickness of 7 mm and a surface unit weight of 560 g / cm ^{3 was} used as the inner layer (A) and 900 were applied on chopped fiberglass canvases applied on both sides g polyurethane composition according to the recipe 1 (P). As the outer layer (C), we used a compact, obtained by deep drawing, multilayer thermoplastic film made of ASA / PMMA with a thickness of 1.40 mm and an initial bending stiffness of 3.43 × 10 ⁴ N · mm ² . As a decorative material (D), foaming-protected textiles with a surface unit weight of 180 g / cm ^{3 were used} . The temperature of the working body during the pressing process was about 60 ° C on the side of the outer layer and about 90 ° C on the side of the decorative layer. The resulting multilayer block with a thickness of 7.2 mm had a density of 517 kg / m ³ and bending stiffness of 5.71 × 10 ⁶ N · mm ² .

The bending stiffness of the outer layer (C) due to the formation of a composite with a polyurethane compound is significantly increased by 166 times.

Claims (3)

1. A multilayer block with a density in the region of 400 to 700 kg / cm ³ of A) the inner layer of thermoformed polyurethane foams, paper, metal or plastic honeycombs, B) fiber layers located on both sides of the inner layer and impregnated with a polyurethane resin selected from the group consisting of fiberglass canvas, glass wool, combined disordered fiberglass, fiberglass fabric, chopped or ground fiberglass or mineral fibers, canvas and natural fiber knitted fabrics , chopped natural fibers, as well as canvases, cotton wool and fabrics based on polymer, carbon or aramid fibers, as well as their mixtures, moreover, polyurethane obtained by interaction 1) at least one polyol as one component with an average hydroxyl number from 300 to 700, which contains at least one short chain polyol and at least one long chain polyol, while the starting polyols have a functionality of from 2 until 6, 2) at least one polyisocyanate, 3) water 4) activators, 5) stabilizers, as well as 6) if necessary, other auxiliaries, release agents and additives, C) an outer layer with a class A surface quality selected from the group consisting of metal foil or sheet, as well as compact thermoplastic plastic composites of polymethyl methacrylate, acrylic ester of modified styrene-acrylonitrile terpolymer, polycarbonate, polyamide, polybutylene terephthalate and / or polyphenylene oxide, on one fiber layer, and D) if necessary, a decorative layer selected from the group consisting of textile substances that are coated with a thermoplastic polyurethane film to protect against foaming, compact or foamed polymer films, and also sprayed films or RIM films - films obtained by injection of melt from polyurethane , on the second layer of fiber. 2. The multilayer block according to claim 1 for the manufacture of modules for roofs, housings for motors, luggage racks, door or floor plates for cars. 3. The method for producing the multilayer block according to claim 1, in which a layer of fiber B) impregnated with polyurethane components is applied to the inner layer A) on both sides, and this combined material is processed in the mold by closing the mold, finally reacting the polyurethane components and binding with the outer layer C) and, if necessary, with a decorative layer D) in a multilayer block.