Compound of Wood and Synthetic Material

Abstract

The invention relates to a compound of a thermoplastic synthetic material and a strengthening components whereby the technical problem of indicating a high-grade compound work material at low production cost, in particular for outdoor application has been solved in that the thermoplastic synthetic material is a synthetic polyester, preferably a polyethylene terephthalate (PET), and the strengthening components is an organic filler, preferably fine-particle wood or wood fibers. The invention also relates to the production of structural parts from the component as well as the structural parts themselves.

Description

DETAILED DESCRIPTION OF THE INVENTION

Especially with rope-shaped products designed for outdoor use it man be advisable to apply a coating of synthetic material by means of co-extrusion. It is thus possible to produce improved weather protection.

EXAMPLE

Wood with a characteristic sieve curve as in table 1 is mixed with PET flakes. The wood originates in an industrial production line for chipboards and is not processed especially. Moisture is around 2%. The PET flakes come from shredded PET bottle material. Labels, seals and residual pollution from food (soft drinks) were not removed. The mixing ratios of wood and PET were 50:50 9HP 03), 40:60 (HP02) and 30:70 (HP 01).

From the mixture an extruder produced a granulate having a medium to dark brown color. From the granulate thus obtained board-shaped injection molded parts (approximately 15×15×0.5 cm³) were produced, and these had the following characteristics after storage in normal climate (23° C., 5% relative humidity) for 14 days:

TABLE 2
Recipe	HP 01	HP 02	HP 03
Flexural strength	64.24	85.53	92.37
[N/mm2]
Impact strength	4.549	5.323	5.550
[kJ/m2]
Density	1.345	1.356	.345
[g/cm3]
2 h water swelling1	0.3	0.4	0.4
[%]
24 h water swelling1	0.5	0.7	0.9
[%]
2 h Flushing agent2	0.4	0.2	0.5
solution [%]
24 h Flushing agent2	0.6	0.5	1.0
solution [%]
Remarks	Wood/PET	Wood/PET	Wood/PET
	30/70% per weight	40/60% per weight	50/50% per weight
1Swelling behavior when stored in water for 2 h and 24 h, as well as with
2Storage in 20 g flushing agent solution for 1 liter water;
Flushing agent: BULSAN soap cleanser.

In addition, samples of the recipe HP 03 were subjected to artificial weathering according to Table 3 and edge swelling was examined in accordance with EN 13329.

The effects of artificial weathering on the mechanical characteristics are shown in Table 4

TABLE 3
Cycles of artificial weathering:
	Step	Function	Temperature	Duration
	1	Condensation	45°	24	h
	2	Below-cycle step		48	x
		3 + 4
	3	UV illumination	60°	2.5	h
	4	Spraying phase		0.5	h
	5	Start with step 1

Explanations/Technical Data:

• • The temperature during the UV illumination phase was 60° C.
  • The temperature during the condensation phase is 45° C.
  • The illumination strength of the UV lamps is 0.77 W/m².
  • The spraying of the samples during the spray phase (rain) is at normal water temperature.
  • Total duration per cycle: 168 h
  • Total duration: 2016 h (12 weeks) with 12 times repetition of the cycle.

TABLE 4
Changes in flexural resistance and impact strength
after 400 h, 1000 h, and 2016 h artificial weathering
Recipe                           HP 03
Flexural resistance after 400 h  8%
Flexural resistance after 1000 h 13%
Flexural resistance after 2016 h 18%
Impact strength after 400 h      No significant connection
Impact strength after 1000 h     No significant connection
Impact strength after 2016 h     No significant connection

Swelling of the HP 03 mixture (50% wood/50% PET) at the edges as measured according to EN 13329 resulted in values below 2%.

Claims

1. Compound of a thermoplastic synthetic material and a strengthening component, wherein the thermoplastic component is synthetic polyester and the strengthening component organic filler.

2. Compound as in claim 1, wherein the thermoplastic component is polyethylene terephthalate (PET.

3. Compound as in claim 1, wherein the organic strengthening components fine-particle wood or wood fibers.

4. Compound as in claim 1, wherein the PET is waste from the collection of used PET products, in particular from the collection of packing material.

5. Compound as in claim 1, wherein an inorganic filler is provided.

6. Compound as in claim 5, wherein the inorganic filler is provided to influence the moisture resistance and/or the specific weight and/or for coloring.

7. Compound as in claim 1, wherein an additive is provided to influence electric conductivity, UV resistance, aging behavior, odor, coatability, bondability, weldability, chipability and/or fire resistance.

8. Compound as in claim 1 wherein an organic or physical foaming agent is provided to influence porosity and/or thermal characteristics.

9. Compound as in claim 1, wherein the mixing ratio between wood and synthetic polyester lies within the range from 7:30 to 30:70, in particular from 60:40 to 30:70, and preferably from 50:50 and 30:70.

10. Process for the production of a structural part from a compound as in claim 1, wherein the compound is produced through thermoplastic conversion, preferably through extrusion or injection molding.

11. Process as in claim 10, wherein a board-shaped structural part is produced.

12. Process as in claim 11, wherein the structural part is postprocessed by means of a calendaring device or double band press downstream of the extruder.

13. Process as in claim 10, wherein a rope-shaped structural part is produced.

14. Process as in claim 10, wherein at least one surface of the structural part is provided with a coating.

15. Process as in claim 14, wherein the surface is laminated with a laminate, an impregnator, a foil, in particular metal foil, with cardboard, with leather, with linoleum, with cork or with wood, in particular veneer.

16. Process as in claim 14, wherein the surface is coated with a powder coating.

17. Process as in claim 14, wherein the coating is applied in liquid form.

18. Process as in claim 14, wherein a color coating, lacquer or artificial resin is used as the liquid coating.

19. Process as in claim 14, wherein a coating of synthetic material is applied by means of co-extrusion.

20. Structural part consisting at least in part of a compound as in claim 1.

21. Structural part as in claim 20, wherein the structural part has been produced by means of a process according to claim 10.

22. Structural part as in claim 20, wherein the structural part is used as wall, ceiling or floor covering.

23. Structural part as in claim 20, wherein the structural part is used as a profile, in particular elements of window frames or door frames.

24. Structural part as in claim 20, wherein at least one surface of the structural part is provided with a coating.

25. Structural part as in claim 20, wherein swelling when stored in water for over 2 hours is less than 0.5% and less than 1.0% at 24 hours and more.

26. Structural part as in claim 20, wherein the change in flexural resistance of the structural part is less than 10% and in particular 8% with artificial weathering for over 400 hours.

27. Structural part as in claim 20, wherein the change in flexural resistance of the structural part is less than 15% and in particular 13% with artificial weathering for over 1000 hours.

28. Structural part as in claim 20, wherein the change in flexural resistance of the structural part is less than 20% and in particular 18% with artificial weathering for over 2016 hours.

29. Structural part as in claim 20, wherein the swelling at the edges is less than 2% as measured according to EN 13329.