MODIFIED TIMBER

Abstract

The invention relates to a treatment composition for timber or wood including fire-retardant and either a crosslinking agent or a fixing agent or both, whereby the composition is boron- and halogen-free.

Claims

1. A boron-free and halogen-free treatment composition for timber and/or wood, comprising: a) a fire-retardant comprising the moiety —N—C(═X)—N— with X being O, S, or substituted or unsubstituted nitrogen; and at least one of the components b) or c): b) a cross-linking agent, or c) a fixing agent.

2. The composition of claim 1, whereby the cross-linking agent comprises a 2-imidazolidone moiety.

3. The composition of claim 1, whereby the cross-linking agent comprises a compound of the following structure ##STR00004## whereby R.sup.1 and R.sup.2 are independently from each other OH or OR.sup.5 whereby R.sup.5 for every residue independently is C.sub.1-C.sub.5 alkyl, —CH.sub.2O—C.sub.nH.sub.2n—OH, or —CH.sub.2O—C.sub.nH.sub.2n—O—C.sub.mH.sub.2mOH with n and m being independently 2 or 3; and R.sup.3 and R.sup.4 are independently from each other hydrogen, R.sup.5 for every residue independently, —CH.sub.2OR.sup.5 for every residue independently, or CH.sub.2OH.

4. The composition of claim 1, whereby the fixing agent comprises cyanoguanidin-diethylenetriamine-epichlorohydrin-polymer.

5. The composition of claim 1, whereby the fire retardant includes an urea and/or guanidine moiety.

6. The composition of claim 1, whereby the fire retardant is chosen from one of the following substances: urea, guanidine, or phenylguanidine salts.

7. The composition of claim 1, whereby the fire retardant comprises a phosphate.

8. The composition of claim 1, whereby the ratio (in wt/wt) of the fire retardant and the crosslinking agent (whereby when more than one crosslinking agent and/or fire retardant is present this relates to the total weight) is ≥0.05:1 to ≤10:1.

9. The composition of claim 1, whereby the composition furthermore comprises a catalyst.

10. The composition of claim 1, whereby the composition is catalyst-free.

11. (canceled)

12. A timber and/or wood composite material whereby at least a part of the timber and/or wood of the composite material is impregnated with a composition according to claim 1.

13. An application method for applying a composition according to claim 1 onto a timber and/or wood to be treated, comprising the steps of: a) Optionally pre-drying the timber and/or wood to be treated, b) Impregnating the timber and/or wood to be treated with an aqueous solution of the composition at elevated pressure, and c) Drying the impregnated timber and/or wood.

14. The method of claim 13, whereby in step b) the content of the composition (in g per 100 ml water prior to addition) is ≥0.5 g to ≤80 g.

15. The method of claim 13, whereby step c) comprises at least two drying steps which are performed at different temperatures with the temperature increasing from each step to the other.

Description

[0096] FIG. 1 shows a diagram showing the maximum weight loss of two inventive and two comparative samples

[0097] FIG. 2 shows a diagram showing the burning rate for the specimen of FIG. 1

[0098] FIG. 3 shows a diagram showing the burning time for the specimens of FIG. 1

[0099] FIG. 4 shows a diagram the glowing time for the specimens of FIG. 1

[0100] FIG. 5 shows a diagram showing the maximum swell rates of one inventive and four comparative samples;

[0101] FIG. 6 shows a diagram showing the Anti Swell Efficiency (ASE) of the samples of FIG. 5.

[0102] FIG. 7 shows a diagram showing the water vapor uptake (W24.sub.100% RH), water vapor release (W24.sub.0% RH) and liquid water uptake (W24.sub.submerged) for the specimen of FIG. 5

[0103] FIG. 8 shows a diagram showing the maximum weight loss of three inventive samples and one comparative sample

[0104] FIG. 9 shows a diagram showing the burning rate of the samples of FIG. 8

[0105] FIG. 10 shows a diagram showing the burning time of three inventive samples;

[0106] FIG. 11 shows a diagram showing the glowing time of the samples of FIG. 10.

[0107] FIG. 12 shows a diagram showing the WPG of one inventive sample and one comparative sample

[0108] FIG. 13 shows a diagram showing the maximum weight loss of one inventive sample and two comparative samples; and

[0109] FIG. 14 shows a diagram showing the burning rate of one inventive sample and two comparative samples

[0110] The invention is furthermore explained by the following examples which are illustrative only and non-binding:

EXAMPLE I

[0111] In Example I, an impregnation solution comprising 20 g DMDHEU and 10 g Monoguanidinphosphate per 100 ml water was used. Oven-dry (0% MC) samples of Scots pine sapwood (Pinus sylvestris L.) were impregnated with the impregnation solution in a vacuum-pressure impregnation process of 1 hr vacuum at 50 mbar followed by 1 hr overpressure at 12 bar. Fully impregnated samples were first dried at 25° C. for 110 hrs, then drying and curing at 120° C. for 48 hrs in a drying oven occurred.

EXAMPLE II

[0112] In Example II, an impregnation solution comprising 9 g of an 1:1 mixture of potassiumdihydrogen phosphate and urea and 19 g cyanoguanidin-diethylenetriamine-epichlorohydrin-polymer was used. Oven-dry (0% MC) samples of Scots pine sapwood (Pinus sylvestris L.) were impregnated with the impregnation solution in a vacuum-pressure impregnation process of 1 hr vacuum at 50 mbar followed by 1 hr overpressure at 12 bar. Fully impregnated samples were pre-dried at 25° C. for 12 hrs. Afterwards samples were dried by stepwise temperature increase (12 hrs intervals) at 40° C., 60° C., 80° C. and 103° C. before curing at 130° C. for 5 hrs in a drying oven.

EXAMPLE III

[0113] In Example III an impregnation solution comprising 20 g DMDHEU and 5 g Monoguanidinphosphate per 100 ml water was used. The treatment method was identical to Example I.

EXAMPLE IV

[0114] In Example IV an impregnation solution comprising 20 g methylolated DMDHEU and 5 g Monoguanidinphosphate per 100 ml water was used. The treatment method was identical to Example I.

EXAMPLE V

[0115] In Example V an impregnation solution comprising 20 g DMeDHEU and 5 g Monoguanidinphosphate per 100 ml water was used. The treatment method was identical to Example I.

COMPARATIVE EXAMPLES

[0116] As comparative examples [0117] an untreated timber [0118] a timber impregnated with sodium polyborate [0119] a timber impregnated with monoguanidiniumphosphate; and [0120] a timber impregnated with DMDHEU crosslinking agent [0121] a timber impregnated with an impregnation solution comprising 20 g DMDHEU and 5 g Diammoniumphosphate (as fire retardand) per 100 ml water (Comparative Example I)

[0122] were used. The impregnation and drying, if applicable, occurred in analogous fashion to Example I.

[0123] Leaching Tests

[0124] The attribute ‘with leaching’ marks all samples which were subjected to a 14-days cold water leaching procedure following European Norm EN 84 (1997) before testing respective material characteristics.

[0125] Burning Test

[0126] All samples were subjected to a “bunsen-burner flaming test”. After treatment with the impregnation solutions as described before, dried and cured samples of 13×4×125 (ax.) mm.sup.3 were conditioned at 20° C., 65% RH prior testing. The specimens were at one end fixed in a holder forming an angle of 45°. Specimen plus holder were placed on a balance in a way that the specimen was hanging down next to the balance. Before fixing the specimen, the balance was tared and the mass of the conditioned sample measured to the nearest 10.sup.−3 g. Based on this starting weight of the specimen, the moisture content was calculated on the basis of the original dry weight of the wood before treatment. By a Bunsen burner, the specimen's tip was ignited during 30 s of exposure to the flame. The strength and height of the flame of the Bunsen burner was always equal for all specimens. The weight of the specimen was recorded in 10 s intervals and at the same time it was assessed whether the specimen was burning or glowing. The mass loss of the specimens was related to the original oven-dry weight before treatment (pure wood substrate without chemical). Parameters which were calculated in order to assess the fire resistance of respectively treated wood were the maximum mass loss, maximum mass loss per ten-second interval (burning rate), burning time and glowing time. The test was conducted with n=10 specimens per treatment collective.

[0127] Swelling and Shrinking Test (Dimensional Stability)

[0128] Specimens of 25×25×10 (ax.) mm.sup.3 were after treatment with cross-linking agents and/or fire retardants oven-dried at 103° C. until constant mass (0% MC). Oven-dry weights and dimensions were measured and samples subsequently water saturated with demineralised water by applying a vacuum of 100 mbar for 30 min, followed by a storage in demineralised water for 24 hrs. Afterwards dimensions were measured in maximum swollen state and based on the maximum swell rates the Anti-Swell-Efficiency [ASE, %] was calculated by comparing swell rates of modified to those of untreated wood. Specimens were re-dried to oven-dry state and the described ASE cycle repeated four times in order to regard long-term effects of respective treatments on the swelling and shrinking of wood. With increasing cycle number decreasing ASE values would indicate effects of a chemical leaching due to minor fixation.

[0129] Water Vapor Uptake and Release

[0130] Short-term water uptake and release tests were conducted with specimens of 5×10×100 (ax.) mm.sup.3 over a period of 24 hrs. Respective specimens were oven-dried and weighed to the nearest 10.sup.−3 g and stored for 24 hrs. in 100% RH at 25° C. Afterwards the water vapor uptake (W24.sub.100% RH [%]) was calculated. Samples were stored for another 14 days in 100% RH and weighed again at approx. fiber saturation. After that, specimens were exposed directly on freshly activated silica gel and weighed again after 24 hrs. The water vapour release (W24.sub.0% RH [%]) during 24-h exposure was calculated. Specimens were again oven-dried at 103° C. until constant mass, weighed to the nearest 10.sup.−3 g and submerged in demineralised water at surrounding climate of 25° C., 65%. After 24 hrs. submersion samples were weighed again and the liquid water uptake [W24.sub.submered] calculated.

[0131] Results

[0132] FIG. 1 shows a diagram showing the maximum weight loss of two inventive and two comparative samples which were tested both before and after leaching according to EN 84 (1997), FIGS. 2 to 4 show the burning rate, burning time and glowing time of the samples of FIG. 1. As can be seen the inventive samples show an increased fire-retarding behaviour.

[0133] FIG. 5 shows a diagram showing the maximum swell rates of one inventive and four comparative samples on which basis the Anti Swell Efficiency (ASE) was calculated for samples previously leached according to EN 87 (1997), which is shown in FIG. 6. FIG. 7 is a diagram showing the water vapor uptake (W24.sub.100% RH), water vapor release (W24.sub.0% RH) and liquid water uptake (W24.sub.submerged) for the specimen of FIG. 5 which were tested without being leached according to EN 84 (1997). The improved effect of the inventive samples can clearly be observed.

[0134] FIG. 8 shows the maximum weight loss, FIG. 9 the burning rate of three inventive samples and one comparative sample which were tested without being leached according to EN 84 (1997). FIG. 10 shows burning time, FIG. 11 the glowing time of the three inventive samples without leaching of three inventive samples. Again in FIGS. 8 to 11 the improved fire resistance is clearly visible.

[0135] FIGS. 12 to 14 show the WPG (weight percentage gain), maximum weight loss and burning rate for Inventive Example III, Comparative Example I and untreated control. Again on FIGS. 12 to 14 the improved fire resistance is clearly visible.

[0136] The particular combinations of elements and features in the above detailed embodiments are exemplary only; the interchanging and substitution of these teachings with other teachings in this and the patents/applications incorporated by reference are also expressly contemplated. As those skilled in the art will recognize, variations, modifications, and other implementations of what is described herein can occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the foregoing description is by way of example only and is not intended as limiting. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. The invention's scope is defined in the following claims and the equivalents thereto. Furthermore, reference signs used in the description and claims do not limit the scope of the invention as claimed.