Edge strip

Abstract

The invention relates to an edge strip, especially for panels of pieces of furniture, comprising a hot-melt layer which consists of at least one easy-flow polyolefin and the rheological behavior of which can be controlled by means of the melt flow rates of the polyolefins used in hot-melt layer. The invention further relates to a method for producing an edge strip of said type as well as to a panel for pieces of furniture that is connected to an edge strip of said type.

Claims

1. The edging strip, in particular for furniture panels, comprising a melt layer composed of a mixture of free-flowing polyolefins selected from a combination of at least two homopolypropylenes or a combination of at least one homopolypropylene and at least one copolymer of propylene, where homopolypropylenes and copolymers of propylene present in said combinations have different melt flow indices (MFI), where the melt flow indices of the homopolypropylenes are in the range from 100 g/10 min. to 1500 g/10 min (in accordance with ISO 1133, 230 C., 2.16 kg).

2. The edging strip as claimed in claim 1, characterized in that the melt flow indices of the copolymers of propylene are at least 3 g/10 min. (in accordance with ISO 1133, 230 C., 2.16 kg).

3. The edging strip as claimed in claim 1, characterized in that the melt flow index (MFI) of the free-flowing polyolefin is at least 200 g/10 min. (in accordance with ISO 1133, 230 C., 2.16 kg).

4. The edging strip as claimed in claim 1, characterized in that the copolymers of propylene are copolymers of polypropylene and polyethylene.

5. The edging strip as claimed in claim 1, characterized in that the modulus of elasticity of the melt layer is no more than 1400 MPa.

6. The edging strip as claimed in claim 1, characterized in that the melting point of the melt layer is no more than 160 C.

7. The edging strip as claimed in claim 1, characterized in that the melt layer includes a pigment, a filler, and an additive.

8. The edging strip as claimed in claim 1, characterized in that the edging strip has an upper layer bonded to the melt layer.

9. The edging strip as claimed in claim 1, characterized in that the melt layer is composed of same polyolefin as other layers of the edging strip that are present.

10. The edging strip as claimed in claim 1 having an upper layer composed of a polyolefin selected from a homopolypropylene, a copolymer of propylene, or a combination thereof.

11. The edging strip as claimed in claim 1, characterized in that hardness and melting point of the melt layer is about the same as that of other layers of the edging strip that are present, and the edging strip has a constant melting point.

12. The edging strip as claimed in claim 1, characterized in that the thickness of the edging strip is in the range of about 0.3 to 4 mm, and visible upper side of the edging strip has been laminated with a plastics foil or with a metal foil, and/or has been embossed and/or printed and/or coated.

13. The edging strip as claimed in claim 1 having bulk patterning.

14. The edging strip as claimed in claim 1, characterized in that an intermediate adhesion promoter is present between incompatible polymer layers that cannot be coextruded.

15. The edging strip as claimed in claim 1, characterized in that an adhesion promoter is present between the melt layer and other layers that are present.

16. The edging strip as claimed in claim 1, characterized in that the same polymer is present in an upper layer and in the melt layer, and provides homogeneity of subsequent machining performance, of hardness and of softening temperature for the entire edging strip.

17. The edging strip as claimed in claim 1, characterized in that a pigment and additional substance that absorbs energy are present in the melt layer.

18. The edging strip as claimed in claim 1, characterized in that a pigment and an additional substance that absorbs energy are present in upper layers that are present.

19. The edging strip as claimed in claim 1, characterized in that an adhesion promoter is present the melt layer and is composed of a liquid mixture comprising water and/or organic solvents, binders and mineral fillers.

20. The edging strip as claimed in claim 1, characterized in that the melt layer and/or an intermediate layer has/have a foam structure.

21. A furniture panel with an edging strip as claimed in claim 1, characterized by an adhesive bond between the melt layer and an edge of the furniture panel.

22. The furniture panel as claimed in claim 21, characterized in that the furniture panel is composed of wood, wood-based materials, wood-substitute materials, plastic, metal, glasses, stone, ceramic or a combination thereof.

23. Adhesive thermoplastic composition suitable for producing a melt layer of an edging strip and comprising a free flowing mixture of polyolefins having different melt flow indices (MFI) and consisting of non-polar monomers, the mixture having a melt flow index (MFI) of at least 100 g/10 min. and the polyolefins being selected from the group consisting of a combination of copolymer of propylene and a homopolypropylene, and a combination of at least two homopolypropylenes, the polyolefins present in said combinations having different melt flow indices.

Description

(1) The examples and drawings below provide still further explanation of the invention.

(2) FIGS. 1 to 3 show an edging strip of the invention which has been applied to a wood-based panel 3. The wood-based panel 3 is a sheet of MDF. The edging strip comprises an upper layer 1 and a melt layer 2. A groove 4 (0.92.0 mm) has been milled into the wood-based panel 3 in order to determine the penetration depth of the molten melt layer 2 (see example 6).

EXAMPLES 1 TO 5

(3) Eight colored edging strips, embodied as two-layer edging strips, comprise an upper layer and a lower layer.

(4) PP Edging:

(5) Upper Layer: PP homopolymer with/without PP copolymer (PP/PE) with/without TPE elastomers with/without fillers (chalk, talc, wollastonites, kaolin) with/without pigments with/without additives

(6) Functional Layer:

(7) 1.sup.st example 90% of MFI 1200 PP homopolymer 10% of pigments/additives (IR absorbers)

(8) 2.sup.nd Example 50% of MFI 1200 PP homopolymer 40% of MFI 100 PP homopolymer 10% of pigments/additives

(9) 3.sup.rd Example 30% of MFI 1200 PP homopolymer 60% of MFI 100 PP homopolymer 10% of pigments/additives

(10) 4.sup.th Example 10% of MFI 1200 PP homopolymer 80% of MFI 100 PP homopolymer 10% of pigments/additives

(11) 5.sup.th Example 30% of MFI 1200 PP homopolymer 40% of MFI 100 PP homopolymer 20% of PP/PE copolymer 10% pigments/additives

(12) 6.sup.th Example 9% of MFI 1200 PP homopolymer 81% of MFI 120 PP homopolymer 10% of pigments/additives

(13) 7.sup.th Example 22.5% of MFI 1200 PP homopolymer 67.5% of MFI 120 PP homopolymer 10% of pigments/additives

(14) 8.sup.th Example 45% of MFI 1200 PP homopolymer 45% of MFI 120 PP homopolymer 10% of pigments/additives

EXAMPLE 6

Correlation Between Melt Layer MFI and Flow Distance and Adhesion Properties

(15) Plastics edgings 1 to 3 were manufactured with the melt-layer formulations set out in table 1. The thickness of the melt layer is about 0.2 mm. Alongside the polymers listed, the melt layer was white-pigmented and comprised an IR absorber as additive. The edgings were processed in an edge-gluing machine using a diode laser assembly with power rating 25 J/cm.sup.2.

(16) TABLE-US-00001 TABLE 1 formulations of melt layers Formulation of functional layer MFI (230 C./2.16 kg) Formulation PP in accordance with ISO 1133 [g/10 min] Mixing No. polymer of the polymers used ratio 1 A 1200 10 B 120 90 2 A 1200 25 B 120 75 3 A 1200 50 B 120 50

(17) Table 2 shows the results from testing of flow depth of the melt layer and from a roller-peel test. Flow depth was tested by preparing cross sections as in FIGS. 1 to 3 and studying these under a microscope using reflected light with an optical scale.

(18) FIG. 1 shows a cross section through an edging strip whose melt layer 2 was produced by using formulation No. 1 (see table).

(19) FIG. 2 shows a cross section through an edging strip whose melt layer 2 was produced by using formulation No. 2 (see table).

(20) FIG. 3 shows a cross section through an edging strip whose melt layer 2 was produced by using formulation No. 3 (see table).

(21) The wood-based panel 3 in FIGS. 1 to 3 is an MDF sheet of thickness 19 mm.

(22) The depiction in FIGS. 1 to 3 is not to scale.

(23) All of the tests were carried out three times or in each case with three parallel samples. The results set out in table 2 in each case represent the average values from the three tests.

(24) TABLE-US-00002 TABLE 2 test results Flow depth Max. penetration Roller peel test depth (100 mm/min) (0.9 2.0 mm Average value of Average value of Formulation groove in MDF Groove fill level peel force for peel force for MDF No. sheet) [mm] [%] particle board [N] sheet [N] 1 0.82 80 47 46.5 2 0.85 90 56 83.0 3 0.90 100 66 197.5

(25) It can clearly be seen that not only the penetration depth but also the adhesion between the edging and the panel can be influenced/controlled by using polymers of different MFI values. As (mixture) MFI increases, flow depths and adhesion values are increased and thus improved.

(26) The improvement of adhesion is particularly clear when MDF sheets are used as backing material. Greater flow depth has the advantage that the cracks generally present in practice in the surface material of the panel are filled more satisfactorily by the inflowing functional-layer material. This could be clearly seen in the case of the tests depicted in FIGS. 2 and 3, where the cavity 5 of the groove 4 was filled more satisfactorily (FIG. 2) or entirely (FIG. 3). The resistance of the edge-banded panels to water and to water vapor is therefore increased, and the risk of swelling of the wood-based panels is thus reduced. At the same time, there is in some cases a marked reduction of the residual thickness of the melt layer as (mixture) MFI increases, because of improved flow of the melt layer (see reduction of thickness of melt layer 2 in FIGS. 2 and 3 in comparison with FIG. 1). It could be observed here that a larger melt bead was produced between panel and edging, which in turn has an advantageous effect on the sealing of the panel by the edging.

KEY

(27) 1 Upper layer 2 Melt layer 3 Wood-based panel 4 Groove 5 Cavity