WO2018177483A1

WO2018177483A1 - Zirconium oxide stabilised by transition metal oxide as a bonding enhancer for plastic moulded bodies

Info

Publication number: WO2018177483A1
Application number: PCT/DE2018/200028
Authority: WO
Inventors: Wolfgang Fischer
Original assignee: Lisa Dräxlmaier GmbH
Priority date: 2017-03-28
Filing date: 2018-03-22
Publication date: 2018-10-04
Also published as: DE102017106647B4; DE102017106647A1

Abstract

The invention relates to the use of a ceramic powder based on zirconium (di)oxide, the ceramic powder containing a tetragonal and/or cubic zirconium (di)oxide which is at least partially stabilised by rare earth metal oxide, in a thermoplastic or thermosetting polymer moulded body (1, 2) and/or an adhesive layer (3). The zirconium (di)oxide stabilised by rare earth metal oxide is used as a bonding enhancer for the bonding of adhesives to the polymer moulded body.

Description

TRANSITION METAL OXIDE STABILIZED ZIRCONIUM DIOXIDE AS A RESISTANT IN PLASTIC FORM BODY

Technical area

The present invention relates to the use of a zirconium (di) oxide-based ceramic powder containing at least partially rare earth metal-stabilized tetragonal and / or cubic zirconium (di) oxide in a thermoplastic or thermoset polymer molding to improve adhesion in the bonding of adhesives with the polymer molding, the underlying polymer molding, and a method for producing the molding and its use.

In the meantime, plastics account for between 15 and 20 percent by weight and are increasing in automotive engineering. These are both exterior and interior parts, for example, blends, d. H. Mixtures of high impact polypropylene with other polyolefins for many years, the most important class of materials in the manufacture of such components, such as automobile bumpers and dashboards represent.

Polymeric materials, in particular thermoplastics, but also thermoset materials, tend in tensile and bending stresses adversely cracking in the material structure with resulting total failure, as well as lack or declining adhesive force in bonding. Particularly in stressed parts in the vehicle interior, for example in door panels, instrument panels in the airbag area with firing channel or outdoors in bumper systems or in the cable / electrical area of the engine compartment high loads can occur. It is desirable in the event of damage first to prevent cracking and its spread, as well as a component breakage, but also a replacement of adhesives. State of the art

So far, it has been attempted to minimize or at least delay the aforementioned disadvantages, for example by glass or carbon fiber reinforcement. However, a defective bonding of the components manifests itself in partially impaired mechanical properties, in particular reduced impact strength and notched impact strength or insufficient adhesive force in the case of bonds. The brittle fracture behavior occurs predominantly in reinforced plastics under mechanical overload. An adhesive bond consists of the two parts to be joined and the intermediate adhesive layer. After the wetting, which plays an important role, the phase interfaces experience interactions (physisorption, chemisorption) and mechanical interlocking. Taken together, these three effects are responsible for the adhesion.

According to DE 33 19 619 A mineral-reinforced blends of polypropylene with ethylene-propylene rubbers are increasingly used for some years, with talcum-reinforced blends have found particular attention. Such talc-reinforced blends have u. a. a small length expansion.

Description of the invention

The object of the present invention is therefore to provide a polymer molding which is suitable for the production of bonded parts with high mechanical strength and ensures in addition to a high elongation at break improved adhesion for adhesives. Furthermore, the task also extends to a simple and economical process for producing such moldings.

This object is achieved by a use of a ceramic powder in a polymer molding with the features of claim 1, an adhesive-coated polymer molding according to claim 6 and a method for its preparation according to claim 10 and its use according to claim 1 1. The basic idea of the present invention is that the shaped body or the joining part comprises a thermoplastic or thermosetting polymer and a ceramic powder based on zirconium (di) oxide, where the zirconium (di) oxide is an at least partially transition metal oxide-stabilized tetragonal ( and / or cubic)

Zirconium (di) oxide includes. The transition metal oxide-stabilized serves

Zirconium (di) oxide preferably as an adhesion promoter and improvers of the breaking and / or breaking elongation of the resulting shaped body or a corresponding coating or intermediate layer, for example as an adhesive or paint. In view of the prior art, it was surprising and unforeseeable for the skilled person that the object underlying the present invention with the help of the inventive use and the resulting molded part or

adhesive coated molding could be solved. Namely, a particular advantage of the invention is that zirconium dioxide (ZrO ₂ ), which hitherto has been known only as a proven ceramic implant material and is considered a fracture-resistant and damage-tolerant material, positively influences the mechanical properties of plastics, in particular with regard to the adhesion of adhesives. The addition of, for example, 3 mol% yttrium oxide (Y ₂ O ₃ ), corresponding to 5, 1 wt .-%, leads to a metastable tetragonal Zr0 ₂ phase at room temperature. In the case of very high mechanical stress, analogous to dental ceramics, presumably local stress peaks occur in the polymer molding, which can lead to the formation of microcracks. The voltage field at the crack tip induces the conversion of

Zirconia particles (Zr0 ₂ ) from the tetragonal to the monoclinic phase. Due to the resulting increase in volume of about 4%, the crack edges

compressed and the crack progress slowed down, cf. Fig. 3.

As a result, the adhesion of adhesives, preferably polyurethane hot-melt adhesives, can be markedly increased on the molding.

The polymer molding may for example be made of a polymer compound. The mechanism for increasing the adhesion of adhesives on the

Polymer molding can be advantageously extended to coatings in the form of paints or intermediate layers in the form of adhesives. Preferably, the polymer is selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), polystyrene (PS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyolefins, preferably polyethylene (PE) or, particularly preferred, polypropylene (PP), reinforced or unreinforced, polyamides (PA),

Polyurethanes (PUR), polyacrylates, or mixtures thereof. These can also be fiber-reinforced. This allows numerous plastic vehicle components,

especially center consoles, instrument panels, door panels or exterior parts, especially bumpers, advantageous in terms of their adhesive force for adhesives improve

Preferably, the ceramic powder based on transition metal oxide-stabilized tetragonal (and / or cubic) zirconium (di) oxide is from 0.001 to 15% by weight and the plastic is from 85 to 99.999% by weight in the molded article or article

Polymer compound included. Higher levels of ceramic powder result in poorer processability and increasing brittleness of the material. Preferably, the zirconia has a content of 3 to 1 2 mol%

Transition metal oxide, preferably yttria, to stabilize the tetragonal (and / or cubic) phase. The zirconium dioxide (Zr0 ₂ ) can be advantageously stabilized with cerium oxide (Ce0 ₂ ). The most important stabilizing oxide is yttrium oxide (Y ₂ O ₃ ). An addition of 3 to 1 2 mol% of yttrium oxide has proven to be particularly suitable since, at this concentration, the zirconium dioxide powder is completely in the form of the tetragonal modification. This has due to the characteristic mechanism of conversion gain tetragonal monoclinic on a very high mechanical load capacity. The adhesive-coated molding preferably has an adhesive force> 1 25 N / 5 cm, depending on the zirconium (di) oxide content. This value refers by way of example to a PP molded body. This means an advantageous increase in the adhesive force or

Adhesion for adhesives compared to pure PP. The adhesive-coated shaped body preferably has an adhesive force> 152 N / 5 cm with a zirconium (di) oxide content of> 10%. This value refers by way of example to a PP molded body. This means a further advantageous increase in adhesion or adhesion for adhesives compared to the pure PP.

The adhesive-coated molding further preferably has an adhesive force> 166 N / 5 cm with a zirconium (di) oxide content of> 12%. This value also refers by way of example to a PP molded body. This means a further advantageous increase in adhesion or adhesion for adhesives compared to the pure PP.

The process for producing an adhesion-improved shaped body is carried out by the following steps: a) compounding a thermoplastic or thermosetting polymer with a zirconium (di) oxide-based ceramic powder containing at least partially transition metal oxide-stabilized tetragonal and / or cubic zirconium (di) oxide; b) injection molding, extrusion, hot and cold pressing or rolling;

c) granulating;

d) injection molding of the granules in an injection mold;

e) removing the resulting molding from the injection mold.

The use of an adhesive improved adhesive coated molding described above is carried out as a vehicle component, in particular as a center console,

Instrument panel, door trim or as an outer part, in particular as a bumper.

Examples

In the following the invention is explained in more detail by some examples, without the

To limit the invention.

The examples tabulate as the polymer an unreinforced polypropylene ("PP") and, for reference, glass fiber reinforced (10%) polypropylene ("PP LGF").

Raw materials of the examples: a) polymer matrix of pure polypropylene (PP) ( "DaplenEE002AE") b) "Amperit ^®" (HC Starck GmbH): Zr0 ₂ -Y ₂ 0 ₃ 93/7

c) Reference: glass fiber reinforced (10%, "Nepol GB601 HP") polypropylene

("Daplenl OGF")

The polypropylenes and commercially available oxide Zr0 ₂ -Y ₂ 0 ₃ form an example of the adhesion-promoting base for use in an injection molded part.

Polypropylene (PP) is applied to an injection molding machine in a proportion of 88-95% by mass of 5-12% by mass of Zr0 ₂ -Y ₂ 0 ₃ 93/7 ( "" Amperit ^® ") mixed in the melt, and as a flat shaped body applied. The adhesion tests were carried out on plates (10 × 10 cm), wherein the decor and the polyurethane hot-melt adhesive used were identical; as well as the amount of glue. The hot melt application temperature was in the range of 30-45 ° C. Subsequently, mechanical strength tests were carried out with the cooled mold part, the results of which are shown in the following Table 1:

Table 1 . Adhesive properties of polypropylene with Zr0 ₂ -Y ₂ 0 ₃ .

Table 1 shows first that the admixture of Zr0 ₂ -Y ₂ 0 ₃ causes a significant increase in the adhesive force or adhesion of the adhesive on the molding. Table 1 also shows that the addition of higher proportions of ZrO ₂ -Y ₂ O ₃ further increases the adhesive force of the adhesive. This results in an adjustable adhesion in polymeric materials, especially in polypropylenes.

In the same way it can be seen from Table 2 that the admixture of Zr0 ₂ -Y ₂ 0 ₃ allows a significant reduction of the necessary amount of adhesive with the same or better adhesion, which can not be achieved on pure polypropylene.

In the present invention, Zr0 ₂ -Y ₂ 0 ₃ acts indirectly, since it is firmly embedded in the polymer matrix matrix, but apparently produces a reduced surface activity, and only becomes effective when applying the hot melt adhesive.

Table 2 Influence of the amount of adhesive on the adhesion to PP as a function of Zr0 ₂ - Y ₂ 0 ₃ .

Short description of the figures

Hereinafter, particular embodiments of a molded article with an adhesive layer will be described in more detail with reference to the drawings.

Show:

Fig. 1 is a schematic representation of an inventive

Adhesive coating on a polymer molding;

Fig. 2 is a schematic representation of the phase transformation of

zirconia; and Fig. 3 is a schematic representation of the conversion gain in

Zirconia.

Fig. 1 shows a schematic of the structure of a component 1, 2 with an adhesive coating formed as an intermediate layer 3. Adhesives based on e.g. Polyolefin, preferably polyurethane, or acrylate tend under tensile stresses to cracking and cohesion, see. Arrow in Fig. 1, in the material structure with resulting breakage, especially in stressed parts in a vehicle interior or in the cable or electrical area where bending stresses occur.

The component 1, 2 and / or the adhesive coating 3 comprise a ceramic powder based on a transition metal oxide-stabilized tetragonal (and / or cubic) zirconium (di) oxide. In this case, the transition metal oxide-stabilized zirconium (di) oxide serves as an adhesion promoter both for the moldings 1, 2 and for the adhesive coating 3.

The stabilized zirconia in the tetragonal crystal phase, in an alternative embodiment, may be admixed as a powder in a particular proportion to the adhesive components, for example, one or two component adhesives consisting of polyol and isocyanate hardener prior to mixing or processing, which in the cross-linking reaction in the three-dimensional Matrix is integrated.

The zirconium dioxide would be conceivable as a filler in powder or fiber form. When applied in hot form, the zirconia, embedded in the adhesive matrix, passes from the tetragonal to the monoclinic crystal phase due to the effect of heat, along with an increase in volume, which then minimizes cracking and increases the adhesive force of the adhesive on a polymer molding.

As shown in FIG. 2, pure zirconia exists in three different phases, which are temperature dependent. From room temperature to ~ 1 1 73 ° C, the monoclinic phase is stable. At temperatures above 1137 ° C to ~ 2370 ° C the tetragonal phase is present. Above 2370 ° C, the cubic phase is stable. The at least partially transition metal oxide-stabilized tetragonal (and / or cubic) zirconium (di) oxide is evidently able to break down crack energy in the polymer molding and / or the adhesive coating and to increase the adhesive force for adhesives. As shown in Figure 3, a propagating crack strikes a zirconia particle. It comes to the crack branching and in the presence of the cubic or tetragonal modification of the zirconium (di) oxide to a phase transformation into monoclinic zirconium (di) oxide, wherein the energy degradation occurs. The tetragonal / cubic phase transformation in monoclinic is associated with an increase in volume such that the crack tip is compressed and crack growth is inhibited. This mechanism is so far only for

conversion-enhanced ceramic body known.

Claims

Use of a zirconium (di) oxide-based ceramic powder containing an at least partially rare earth metal-stabilized tetragonal and / or cubic zirconium (di) oxide in a thermoplastic or tetragonal oxide

thermosetting polymer molding (1, 2) and / or an adhesive layer (3), wherein the rare earth metal-stabilized zirconium (di) oxide is used as an adhesion promoter for the bonding of adhesives with the polymer molding.

Use according to claim 1, wherein the adhesive is a polyurethane based hot melt adhesive.

Use according to claim 1 or 2, wherein the polymer in the polymer molding is selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), polystyrene (PS), polycarbonate (PC), polyamides (PA), Polymethyl methacrylate (PMMA), polyolefins, preferably polyethylene (PE) or polypropylene (PP), polyurethanes (PUR), polyacrylates, or mixtures thereof.

Use according to claim 1 to 3, wherein the ceramic powder to 0.001 to 15 wt .-% and the polymer to 85 to 99.999 wt .-% contained in the polymer molded body (1, 2) and / or the adhesive layer (3) is contained.

Use according to claim 1 to 4, wherein the zirconium (di) oxide has a content of 3 to 12 mol% of rare earth metal oxide, preferably yttrium oxide.

Adhesive coated (3) polymer molded body (1, 2) comprising

thermoplastic or thermosetting polymer selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), polystyrene (PS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyolefins, preferably polyethylene (PE) or Polypropylene (PP), polyamides (PA), polyurethanes (PUR), polyacrylates, or mixtures thereof, and a zirconium (di) oxide-based ceramic powder containing at least partially rare earth metal-stabilized tetragonal and / or cubic zirconium (di ) oxide, which has an adhesive force> 125 N / 5cm depending on the zirconium (di) oxide content.

1

The adhesive-coated (3) polymer molded body (1, 2) according to claim 6, wherein the adhesive is a polyurethane-based hot melt adhesive.

8. An adhesive-coated (3) polymer molded body (1, 2) according to claim 6 or 7, which has an adhesive force s 152 N / 5 cm with a zirconium (di) oxide content of> 10%.

9. Adhesive-coated (3) polymer molded body (1, 2) according to one of claims 6 to 8 which has an adhesive force> 166 N / 5 cm with a zirconium (di) oxide content of> 12%.

10. A process for the preparation of an adhesion-improved polymer molding (1, 2) according to one of claims 6 to 9, comprising the following steps: a) compounding a thermoplastic or thermosetting polymer with a ceramic powder based on zirconium (di) oxide, containing at least partially Rare earth metal-stabilized tetragonal and / or cubic

Zirconium (di) oxide;

b) injection molding, extrusion, hot and cold pressing or rolling;

c) granulating;

d) injection molding of the granules in an injection mold;

e) removing the resulting molding from the injection mold.

1 1. Use of an adhesion-improved polymer molding (1, 2) according to any one of claims 6 to 9 for bonding and / or lamination in a vehicle component, in particular a center console, an instrument panel, a door trim or exterior parts.