NZ743873A0

NZ743873A0 - Enhanced performance of wood and engineered wood products using combined durability and flame retardancy

Info

Publication number: NZ743873A0
Application number: NZ743873A
Authority: NZ
Inventors: Ronald Philip Moon
Original assignee: Wood Modification Technologies Limited
Filing date: 2018-06-27

Abstract

Described herein is a treatment method or process and wood products thereof. In particular, a product formulation of a single phase solution combining a wood preservative (durable component) with a Flame Retardant component [FR] to produce a durable Flame Retardant [dFR] treated wood product. The durable component comprises a range of copper based and non-copper based wood preservatives, while the Flame Retardant [FR] component comprises alkali metal silicates and alkali metal aluminate compounds. The durable Flame Retardant [dFR] working solution undergoes chemical impregnation (treatment) followed by a heat (fixation) process step that locks the chemical into the wood making it non-leachable. The durable Flame Retardant [dFR] treated wood products are tested for their enhanced fire performance properties. When heated, wood undergoes thermal degradation and combustion producing gases, vapours, tars and chars. Using the ‘cone calorimeter’ burn test method (AS/NZS 3837), durable Flame Retardant [dFR] treated wood products show a significant reduction in the following parameters: heat release rate (peak & average HRR values), mass loss rate (MLR) and smoke generated values (Smoke Extinction Area - SEA) compared to untreated radiate pine. The main tests being; accelerated weathering and burn tests (AS/NZS3837) all carried out at BRANZ, New Zealand. rable component comprises a range of copper based and non-copper based wood preservatives, while the Flame Retardant [FR] component comprises alkali metal silicates and alkali metal aluminate compounds. The durable Flame Retardant [dFR] working solution undergoes chemical impregnation (treatment) followed by a heat (fixation) process step that locks the chemical into the wood making it non-leachable. The durable Flame Retardant [dFR] treated wood products are tested for their enhanced fire performance properties. When heated, wood undergoes thermal degradation and combustion producing gases, vapours, tars and chars. Using the ‘cone calorimeter’ burn test method (AS/NZS 3837), durable Flame Retardant [dFR] treated wood products show a significant reduction in the following parameters: heat release rate (peak & average HRR values), mass loss rate (MLR) and smoke generated values (Smoke Extinction Area - SEA) compared to untreated radiate pine. The main tests being; accelerated weathering and burn tests (AS/NZS3837) all carried out at BRANZ, New Zealand.

Claims

WHAT IS CLAIMED IS: 1. A process of imparting enhanced durability and fire retardancy properties to lignocellulosic material comprising: a wood preservative; and a flame retardant [FR], consisting of alkali metal silicates and/or alkali metal aluminates that utilise an impregnation treatment process and/or spray, immersion, deluge system such that there is chemical penetration into the cellular internal voids of the lignocellulosic material which becomes insoluble (fixed) on subsequent heating steps.
2. The lignocellulosic material product produced by the process of claim 1, wherein the product possesses a property of increased Fire Retardancy [FR].
3. The lignocellulosic material product produced by the process of claim 1, wherein the product possesses a property of increased durability to fungal decay, rot, and /or insect attack.
4. The product produced by the process of claim 1, wherein the wood preservative in combination with the Flame Retardant [FR] generates an incremental increase in durability to fungal decay, rot and/or insect attack.
5. The wood impregnation treatment process of claim 1, wherein the pressure ranges from 0 to 3,500kpa and vacuum 0 to -90kpa.
6. The wood impregnation treatment process of claim 1 or claim 5, wherein the chemical absorption ranges from 15 to 950 Litres/m (loading).
7. The process of any one of the preceding claims, wherein the process allows for the wood preservative and Flame Retardant [FR] to co-penetrate during the wood impregnation treatment process.
8. The process of any one of the preceding claims, wherein the wood preservatives are selected from any one of the following: Copper Chrome Arsenate (CCA), dissolved Copper Azoles (dCA), micronized Copper Azoles (mCA), Alkaline Copper Quaternary (ACQ), micronized Copper Quaternary (mCQ), water based Azoles including; tri-azoles - propiconazole, tebuconazole, cyproconazole and carbamates including; iodopropynyl Butyl Carbamate (IPBC) and/or combinations thereof.
9. The wood preservatives of claim 8, wherein the preservatives meet hazard class (H) and/or user categories (UC); H3.1, H3.2, H4, H5 (New Zealand), H3, H4, H5 (Australia), UC3A, UC3B, UC4A, UC4B, UC4C & UC5 (United States of America) and/or other equivalent global categories.
10. The process of any one of the preceding claims, wherein the Flame Retardant [FR] are selected from any one of the following: soluble alkali metal silicates including; sodium silicate (ortho, meta, di & tri-silicates), potassium silicate, lithium silicate and soluble alkali metal aluminates including sodium aluminate and potassium aluminate and/or combinations thereof.
11. The Flame Retardant [FR] of claim 10, further comprising aluminium oxide [Al O ] nano-particles (dispersions), aluminium silicate [Al O .SiO ] nano-particles (dispersions) and 2silicon dioxide [SiO ] nano-particle dispersions. 12. The Flame Retardant [FR] of claims 10 or 11, wherein the sodium aluminate and potassium aluminate are stabilised using chelating agents as the stabiliser. 13. The stabilisers as claimed in claim 12, wherein the stabilisers are selected from any one of the following amine compounds; Ethylenediaminetetra-acetic acid (EDTA), Ethylene diamine (EN), Diethylenetriaminepenta-acetic acid (DTPA), (N-(hydroxyethyl)-ethylenediaminetriacetic acid) (HEDTA), Ethylene glycol tetra-acetic acid (EGTA); salts of gluconic acid (“gluconates”), sodium gluconate, potassium gluconate, salts of tartaric acid and ethanolamine compounds, monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA) and/or combinations thereof. 14. The Flame Retardant [FR] of claim 11, wherein the aluminium oxide [Al O ] nano-particles (dispersions), aluminium silicate [Al O3.SiO ] nano-particles (dispersions) and silicon dioxide [SiO ] nano-particle dispersions are suspensions in water or organic solvents. 15. The organic solvents of claim 14, wherein the organic solvents are selected from any one of: ethanol, mineral oils, high and low aromatic hydrocarbons and glycols (ethylene and propylene) and/or combinations thereof.
12. The process of claim any one of the preceding claims, wherein other additives selected from any one of the following: water repellents, colourants, stabilisers, surfactants, and/or combinations thereof for the impregnation and spray treatment processes enhance properties of increased stability, penetration and colour.
13. The process of any one of the preceding claims, wherein the combination of wood preservatives (chemical - durable) and Flame Retardant [FR] (alkali metal silicate and alkali metal aluminates) liquids impregnate internal cells voids and applying a heat or drying step causes the liquid durable (chemical) Flame Retardant [dFR] combination to become insoluble, fixed and encapsulated within the lignocellulosic material.
14. The process of any one of the preceding claims, wherein the combination wood preservatives (treated to H3, H4, H5 or equivalent) and Flame Retardants [FR] including alkali metal silicates and alkali metal aluminates produce a working solution required for the impregnation treatment into the wood or engineered wood products.
15. The process of any one of the preceding claims, wherein the combination wood preservatives (treated to H3, H4, H5 or equivalent) and Flame Retardants [FR] including alkali metal silicates and alkali metal aluminates produce the working solution required for impregnation treatment is followed by the application of liquid alkali metal silicates or liquid metal aluminates that is applied either via spray, brush, immersion or deluge systems to the wood or engineered wood products.
16. The process of any one of the preceding claims, wherein the combination wood preservatives (treated to H3, H4, H5 or equivalent) and Flame Retardants [FR] including alkali metal silicates and alkali metal aluminates, to produce the working solution and whereby the wood preservative is the only working solution that undergoes the impregnation treatment and the liquid alkali silicates or liquid metal aluminate is applied either via spray, brush, immersion or deluge systems to the wood or engineered wood products.
17. The process of any one of the preceding claims, wherein the combination wood preservatives (treated to H3, H4, H5 or equivalent) and Flame Retardants [FR], whereby the liquid alkali metal silicates and liquid alkali metal aluminates are applied via spray, immersion or deluge systems at a temperature range of 0 C to 100 C.
18. The process of any one of the preceding claims, wherein the wood preservative chemical retentions range from 0.1kg/m copper (Cu) to 20kg/m copper (Cu) for the copper based wood preservatives.
19. The process of any one of the preceding claims, wherein the alkali metal silicates (flame retardants) chemical retentions range from 0.2kg/m elemental Si (for Sodium, Potassium & Lithium) to 45kg/m elemental Si (for Sodium, Potassium & Lithium).
20. The process of any one of the preceding claims, wherein the alkali metal aluminates (Flame Retardants) chemical retentions range from 0.2kg/m elemental Al (for Sodium, Potassium & Lithium) to 45kg/m elemental Al (for Sodium, Potassium & Lithium).
21. The process of any one of the preceding claims, wherein the other additives such as water repellents, colourants and the like included in the chemical formulation (working solution) and impregnation treatment process provide other value added properties of wood such as increased dimensional stability and colour.
22. The process of any one of the preceding, wherein the heat (fixation) process temperature for the ‘treated flame retardant’ is within the range 50 C to 150 C.
23. The process of any one of the preceding claims, wherein the thermal modification temperature is in the range of 150 C to 250 C for durable Flame Retardant [dFR] or Flame Retardant [FR] when thermally modified in a kiln.
24. The process of any one of the preceding claims, wherein the durable Flame Retardant [dFR] treated wood product meets Australian Bushfire Standards (AS3959 BAL29) and USA Forest fire Standards (ASTM E 84) respectively.
25. The process of any one of the preceding claims, wherein the lignocellulosic material is selected from any one of the following wood species: radiata pine (pinus radiata), western red cedar and other cedars, Douglas fir, southern yellow pine, scots pine, hoop pine, slash pine and all other soft and hard type pines and/or combinations thereof. FH623925-1 FH623925-2 FH623925-3600 900 1200 1500 1800Time (sec)