NZ743873A - Enhanced performance of wood and engineered wood products using combined durability and flame retardancy - Google Patents
Enhanced performance of wood and engineered wood products using combined durability and flame retardancyInfo
- Publication number
- NZ743873A NZ743873A NZ743873A NZ74387317A NZ743873A NZ 743873 A NZ743873 A NZ 743873A NZ 743873 A NZ743873 A NZ 743873A NZ 74387317 A NZ74387317 A NZ 74387317A NZ 743873 A NZ743873 A NZ 743873A
- Authority
- NZ
- New Zealand
- Prior art keywords
- wood
- flame retardant
- alkali metal
- durable
- chemical
- Prior art date
Links
- 239000002023 wood Substances 0.000 title claims abstract description 139
- 239000003063 flame retardant Substances 0.000 claims abstract description 223
- 238000000034 method Methods 0.000 claims abstract description 112
- 239000000126 substance Substances 0.000 claims abstract description 78
- 239000000203 mixture Substances 0.000 claims abstract description 54
- 239000010949 copper Substances 0.000 claims abstract description 52
- 238000005470 impregnation Methods 0.000 claims abstract description 45
- 229910052802 copper Inorganic materials 0.000 claims abstract description 41
- 230000002335 preservative Effects 0.000 claims abstract description 40
- 239000003755 preservative agent Substances 0.000 claims abstract description 40
- 239000010875 treated wood Substances 0.000 claims abstract description 40
- RYGMFSIKBFXOCR-UHFFFAOYSA-N copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 35
- 239000012224 working solution Substances 0.000 claims abstract description 35
- 229910052910 alkali metal silicate Inorganic materials 0.000 claims abstract description 32
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 31
- -1 alkali metal aluminate compounds Chemical class 0.000 claims abstract description 28
- 239000003171 wood protecting agent Substances 0.000 claims abstract description 20
- 238000009472 formulation Methods 0.000 claims abstract description 17
- 235000008331 Pinus X rigitaeda Nutrition 0.000 claims abstract 2
- 235000011613 Pinus brutia Nutrition 0.000 claims abstract 2
- 241000018646 Pinus brutia Species 0.000 claims abstract 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 33
- 230000014759 maintenance of location Effects 0.000 claims description 31
- 239000000463 material Substances 0.000 claims description 20
- 230000035515 penetration Effects 0.000 claims description 19
- 235000008577 Pinus radiata Nutrition 0.000 claims description 16
- 241000218621 Pinus radiata Species 0.000 claims description 16
- PNEYBMLMFCGWSK-UHFFFAOYSA-N al2o3 Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 15
- 239000006185 dispersion Substances 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 claims description 14
- 239000002105 nanoparticle Substances 0.000 claims description 14
- 238000007654 immersion Methods 0.000 claims description 13
- 239000007921 spray Substances 0.000 claims description 13
- AYWHENVLARCQQQ-UHFFFAOYSA-N copper;1H-pyrrole Chemical class [Cu].C=1C=CNC=1 AYWHENVLARCQQQ-UHFFFAOYSA-N 0.000 claims description 12
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims description 12
- 230000001965 increased Effects 0.000 claims description 11
- 239000007788 liquid Substances 0.000 claims description 10
- 230000004048 modification Effects 0.000 claims description 10
- 238000006011 modification reaction Methods 0.000 claims description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 10
- 241000894007 species Species 0.000 claims description 9
- RGHNJXZEOKUKBD-SQOUGZDYSA-N Gluconic acid Chemical class OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C(O)=O RGHNJXZEOKUKBD-SQOUGZDYSA-N 0.000 claims description 8
- IYJYQHRNMMNLRH-UHFFFAOYSA-N Sodium aluminate Chemical compound [Na+].O=[Al-]=O IYJYQHRNMMNLRH-UHFFFAOYSA-N 0.000 claims description 8
- SMYKVLBUSSNXMV-UHFFFAOYSA-J aluminum;tetrahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[Al+3] SMYKVLBUSSNXMV-UHFFFAOYSA-J 0.000 claims description 8
- 229910001388 sodium aluminate Inorganic materials 0.000 claims description 8
- 241000238631 Hexapoda Species 0.000 claims description 7
- 150000004645 aluminates Chemical class 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 7
- 230000002538 fungal Effects 0.000 claims description 7
- 239000011734 sodium Substances 0.000 claims description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 6
- 239000005995 Aluminium silicate Substances 0.000 claims description 5
- PZZYQPZGQPZBDN-UHFFFAOYSA-N Aluminium silicate Chemical compound O=[Al]O[Si](=O)O[Al]=O PZZYQPZGQPZBDN-UHFFFAOYSA-N 0.000 claims description 5
- 235000005018 Pinus echinata Nutrition 0.000 claims description 5
- 241001236219 Pinus echinata Species 0.000 claims description 5
- 239000004115 Sodium Silicate Substances 0.000 claims description 5
- NTHWMYGWWRZVTN-UHFFFAOYSA-N Sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 5
- 229910001884 aluminium oxide Inorganic materials 0.000 claims description 5
- 229910000323 aluminium silicate Inorganic materials 0.000 claims description 5
- 235000012211 aluminium silicate Nutrition 0.000 claims description 5
- 150000003851 azoles Chemical class 0.000 claims description 5
- 230000001413 cellular Effects 0.000 claims description 5
- 239000003960 organic solvent Substances 0.000 claims description 5
- 150000003839 salts Chemical class 0.000 claims description 5
- 239000000377 silicon dioxide Substances 0.000 claims description 5
- 235000012239 silicon dioxide Nutrition 0.000 claims description 5
- 239000011780 sodium chloride Substances 0.000 claims description 5
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 5
- 239000003381 stabilizer Substances 0.000 claims description 5
- 229940099451 3-iodo-2-propynylbutylcarbamate Drugs 0.000 claims description 4
- WYVVKGNFXHOCQV-UHFFFAOYSA-N Iodopropynyl butylcarbamate Chemical compound CCCCNC(=O)OCC#CI WYVVKGNFXHOCQV-UHFFFAOYSA-N 0.000 claims description 4
- 229940005574 Sodium gluconate Drugs 0.000 claims description 4
- 239000000654 additive Substances 0.000 claims description 4
- 238000011068 load Methods 0.000 claims description 4
- 239000000176 sodium gluconate Substances 0.000 claims description 4
- 235000012207 sodium gluconate Nutrition 0.000 claims description 4
- 240000008997 Araucaria cunninghamii Species 0.000 claims description 3
- 241000218645 Cedrus Species 0.000 claims description 3
- 235000014466 Douglas bleu Nutrition 0.000 claims description 3
- 235000011334 Pinus elliottii Nutrition 0.000 claims description 3
- 241000142776 Pinus elliottii Species 0.000 claims description 3
- 235000017339 Pinus palustris Nutrition 0.000 claims description 3
- 235000005386 Pseudotsuga menziesii var menziesii Nutrition 0.000 claims description 3
- UPMFZISCCZSDND-JJKGCWMISA-M Sodium gluconate Chemical compound [Na+].OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C([O-])=O UPMFZISCCZSDND-JJKGCWMISA-M 0.000 claims description 3
- 241000218638 Thuja plicata Species 0.000 claims description 3
- 238000010521 absorption reaction Methods 0.000 claims description 3
- 239000000174 gluconic acid Substances 0.000 claims description 3
- 229950006191 gluconic acid Drugs 0.000 claims description 3
- 235000012208 gluconic acid Nutrition 0.000 claims description 3
- 239000002480 mineral oil Substances 0.000 claims description 3
- KVOIJEARBNBHHP-UHFFFAOYSA-N potassium;oxido(oxo)alumane Chemical compound [K+].[O-][Al]=O KVOIJEARBNBHHP-UHFFFAOYSA-N 0.000 claims description 3
- UFNOUKDBUJZYDE-UHFFFAOYSA-N 2-(4-chlorophenyl)-3-cyclopropyl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol Chemical compound C1=NC=NN1CC(O)(C=1C=CC(Cl)=CC=1)C(C)C1CC1 UFNOUKDBUJZYDE-UHFFFAOYSA-N 0.000 claims description 2
- DJHGAFSJWGLOIV-UHFFFAOYSA-K Arsenate Chemical compound [O-][As]([O-])([O-])=O DJHGAFSJWGLOIV-UHFFFAOYSA-K 0.000 claims description 2
- 239000005757 Cyproconazole Substances 0.000 claims description 2
- 239000005977 Ethylene Substances 0.000 claims description 2
- PAZHGORSDKKUPI-UHFFFAOYSA-N Lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 claims description 2
- 239000004111 Potassium silicate Substances 0.000 claims description 2
- NNHHDJVEYQHLHG-UHFFFAOYSA-N Potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 claims description 2
- 239000005822 Propiconazole Substances 0.000 claims description 2
- PXMNMQRDXWABCY-UHFFFAOYSA-N Tebuconazole Chemical compound C1=NC=NN1CC(O)(C(C)(C)C)CCC1=CC=C(Cl)C=C1 PXMNMQRDXWABCY-UHFFFAOYSA-N 0.000 claims description 2
- 239000005839 Tebuconazole Substances 0.000 claims description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 claims description 2
- 229940000489 arsenate Drugs 0.000 claims description 2
- 150000004657 carbamic acid derivatives Chemical class 0.000 claims description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 2
- 230000002708 enhancing Effects 0.000 claims description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 2
- 150000002334 glycols Chemical class 0.000 claims description 2
- 229910052912 lithium silicate Inorganic materials 0.000 claims description 2
- 229910052913 potassium silicate Inorganic materials 0.000 claims description 2
- 235000019353 potassium silicate Nutrition 0.000 claims description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 2
- 239000000725 suspension Substances 0.000 claims description 2
- 150000003852 triazoles Chemical class 0.000 claims description 2
- 229960003975 Potassium Drugs 0.000 claims 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims 4
- 229910052744 lithium Inorganic materials 0.000 claims 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims 4
- 229910052700 potassium Inorganic materials 0.000 claims 4
- 239000011591 potassium Substances 0.000 claims 4
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 claims 4
- 229910052708 sodium Inorganic materials 0.000 claims 4
- PIICEJLVQHRZGT-UHFFFAOYSA-N 1,2-ethanediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims 2
- URDCARMUOSMFFI-UHFFFAOYSA-N 2-[2-[bis(carboxymethyl)amino]ethyl-(2-hydroxyethyl)amino]acetic acid Chemical compound OCCN(CC(O)=O)CCN(CC(O)=O)CC(O)=O URDCARMUOSMFFI-UHFFFAOYSA-N 0.000 claims 2
- ZBCBWPMODOFKDW-UHFFFAOYSA-N Diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 claims 2
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 claims 2
- 229960003330 Pentetic Acid Drugs 0.000 claims 2
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Tris Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 claims 2
- KCXVZYZYPLLWCC-UHFFFAOYSA-N edta Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims 2
- HZAXFHJVJLSVMW-UHFFFAOYSA-N ethanolamine Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 claims 2
- DEFVIWRASFVYLL-UHFFFAOYSA-N ethylene glycol bis(2-aminoethyl)tetraacetic acid Chemical compound OC(=O)CN(CC(O)=O)CCOCCOCCN(CC(O)=O)CC(O)=O DEFVIWRASFVYLL-UHFFFAOYSA-N 0.000 claims 2
- 229910001338 liquidmetal Inorganic materials 0.000 claims 2
- 239000005871 repellent Substances 0.000 claims 2
- 230000002940 repellent Effects 0.000 claims 2
- FEWJPZIEWOKRBE-XIXRPRMCSA-N Mesotartaric acid Chemical class OC(=O)[C@@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-XIXRPRMCSA-N 0.000 claims 1
- 229940048195 N-(hydroxyethyl)ethylenediaminetriacetic acid Drugs 0.000 claims 1
- 235000008582 Pinus sylvestris Nutrition 0.000 claims 1
- 241000218626 Pinus sylvestris Species 0.000 claims 1
- HLCFGWHYROZGBI-JJKGCWMISA-M Potassium gluconate Chemical compound [K+].OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C([O-])=O HLCFGWHYROZGBI-JJKGCWMISA-M 0.000 claims 1
- 241000218683 Pseudotsuga Species 0.000 claims 1
- 239000002738 chelating agent Substances 0.000 claims 1
- 150000002169 ethanolamines Chemical class 0.000 claims 1
- 239000004224 potassium gluconate Substances 0.000 claims 1
- 235000013926 potassium gluconate Nutrition 0.000 claims 1
- 229960003189 potassium gluconate Drugs 0.000 claims 1
- 235000002639 sodium chloride Nutrition 0.000 claims 1
- 239000004094 surface-active agent Substances 0.000 claims 1
- 229960001367 tartaric acid Drugs 0.000 claims 1
- 235000002906 tartaric acid Nutrition 0.000 claims 1
- 239000011975 tartaric acid Substances 0.000 claims 1
- 239000000779 smoke Substances 0.000 abstract description 16
- 239000000243 solution Substances 0.000 abstract description 14
- 238000002485 combustion reaction Methods 0.000 abstract description 11
- 238000010998 test method Methods 0.000 abstract description 4
- 230000015556 catabolic process Effects 0.000 abstract description 2
- 230000004059 degradation Effects 0.000 abstract description 2
- 238000006731 degradation reaction Methods 0.000 abstract description 2
- 230000034431 double-strand break repair via homologous recombination Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 abstract 1
- 239000011269 tar Substances 0.000 abstract 1
- 239000000047 product Substances 0.000 description 69
- 238000002386 leaching Methods 0.000 description 17
- 210000004027 cells Anatomy 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 9
- 241000196324 Embryophyta Species 0.000 description 8
- 239000000758 substrate Substances 0.000 description 8
- 239000010876 untreated wood Substances 0.000 description 8
- 238000006297 dehydration reaction Methods 0.000 description 7
- 229910044991 metal oxide Inorganic materials 0.000 description 7
- 150000004706 metal oxides Chemical class 0.000 description 7
- 239000007787 solid Substances 0.000 description 6
- 210000002421 Cell Wall Anatomy 0.000 description 5
- 241000256602 Isoptera Species 0.000 description 5
- 101710011098 BHLH63 Proteins 0.000 description 4
- 235000005205 Pinus Nutrition 0.000 description 4
- 241000218602 Pinus <genus> Species 0.000 description 4
- 240000001416 Pseudotsuga menziesii Species 0.000 description 4
- 238000007792 addition Methods 0.000 description 4
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 4
- 150000001340 alkali metals Chemical class 0.000 description 4
- 239000001913 cellulose Substances 0.000 description 4
- 229920002678 cellulose Polymers 0.000 description 4
- 238000010276 construction Methods 0.000 description 4
- 229920005610 lignin Polymers 0.000 description 4
- 239000003513 alkali Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000036571 hydration Effects 0.000 description 3
- 238000006703 hydration reaction Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 241001116438 Araucaria Species 0.000 description 2
- 235000016013 Pinus leiophylla var chihuahuana Nutrition 0.000 description 2
- 235000008572 Pseudotsuga menziesii Nutrition 0.000 description 2
- GHMLBKRAJCXXBS-UHFFFAOYSA-N Resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 description 2
- 238000006482 condensation reaction Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 235000013490 limbo Nutrition 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 229920001568 phenolic resin Polymers 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 238000009489 vacuum treatment Methods 0.000 description 2
- RLLPVAHGXHCWKJ-HKUYNNGSSA-N (3-phenoxyphenyl)methyl (1R,3R)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate Chemical compound CC1(C)[C@@H](C=C(Cl)Cl)[C@H]1C(=O)OCC1=CC=CC(OC=2C=CC=CC=2)=C1 RLLPVAHGXHCWKJ-HKUYNNGSSA-N 0.000 description 1
- 235000017166 Bambusa arundinacea Nutrition 0.000 description 1
- 240000003917 Bambusa tulda Species 0.000 description 1
- 235000017491 Bambusa tulda Nutrition 0.000 description 1
- 229920002456 HOTAIR Polymers 0.000 description 1
- 229920002488 Hemicellulose Polymers 0.000 description 1
- 229960000490 Permethrin Drugs 0.000 description 1
- 235000015334 Phyllostachys viridis Nutrition 0.000 description 1
- ODGAOXROABLFNM-UHFFFAOYSA-N Polynoxylin Chemical compound O=C.NC(N)=O ODGAOXROABLFNM-UHFFFAOYSA-N 0.000 description 1
- STJLVHWMYQXCPB-UHFFFAOYSA-N Propiconazole Chemical compound O1C(CCC)COC1(C=1C(=CC(Cl)=CC=1)Cl)CN1N=CN=C1 STJLVHWMYQXCPB-UHFFFAOYSA-N 0.000 description 1
- 230000036462 Unbound Effects 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 239000011425 bamboo Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009435 building construction Methods 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000001143 conditioned Effects 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000007706 flame test Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- HANVTCGOAROXMV-UHFFFAOYSA-N formaldehyde;1,3,5-triazine-2,4,6-triamine;urea Chemical compound O=C.NC(N)=O.NC1=NC(N)=NC(N)=N1 HANVTCGOAROXMV-UHFFFAOYSA-N 0.000 description 1
- SLGWESQGEUXWJQ-UHFFFAOYSA-N formaldehyde;phenol Chemical compound O=C.OC1=CC=CC=C1 SLGWESQGEUXWJQ-UHFFFAOYSA-N 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 230000000855 fungicidal Effects 0.000 description 1
- 239000000417 fungicide Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000011121 hardwood Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 235000010446 mineral oil Nutrition 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 239000011120 plywood Substances 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 230000003134 recirculating Effects 0.000 description 1
- 230000001172 regenerating Effects 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N silicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 239000004550 soluble concentrate Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000010025 steaming Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000004083 survival Effects 0.000 description 1
- 230000002588 toxic Effects 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 238000004450 types of analysis Methods 0.000 description 1
- 238000003828 vacuum filtration Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
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 (?xation) 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 ?re 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 signi?cant 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.
Description
ENHANCED PERFORMANCE OF WOOD AND ENGINEERED WOOD PRODUCTS USING COMBINED
DURABILITY AND FLAME RETARDANCY
RELATED APPLICATIONS
This application derives priority from New Zealand patent application number 733302 incorporated
herein by reference.
TECHNICAL FIELD
Described herein is an enhanced performance of wood and engineered wood products (EWP) using
varying combinations of wood preservatives (durability) and flame retardants [FR]. More specifically, a
treatment method or process and wood products thereof that utilise impregnation, spray, immersion
and deluge systems or in varying combinations. The wood preservatives used consist of copper and non-
copper based approved formulations and the flame retardants [FR] being based on alkali metal silicates,
alkali metal aluminates and other chemical additives to achieve enhanced performance.
BACKGROUND ART
Development in the area of treatment impregnation (wood modification) and other applied spray,
immersion and deluge systems has increased significantly due to the demand and need to enhance the
performance properties of untreated, treated (durable) and engineered wood products.
Current heat treatment and chemical treatment processes applied to most wood species fail to achieve
and meet a combined level of durability (for both fungal decay and insect attack - mainly termites) and
flame retardancy prescribed and required by certifiers and territorial authorities globally.
While conventional chemical treated timber (wood preservatives) involves the impregnation of
lignocellulosic material such as wood and engineered wood products with chemical preservatives and
other like compositions, using various vacuum and pressure cycles, which are generally limited to dry
substrates in order to provide ‘free space’ to accommodate the additional fluid uptake ‘working solution’
requirements. It is in the addition of the combined Flame Retardant [FR] to the wood preservative in the
form of a ‘working solution’ that is then impregnated into the wood that determines the effectiveness of
the treatment penetration throughout the wood substrate.
The wood treatments must meet the required product penetration levels and retentions (i.e. loadings -
kg’s per m ) outlined within the prevailing durability standards (for example H3, H4, H5). Fire Retardant
[FR] penetrations and retentions are not prescriptive but rely on the product performance requirements
for Bushfire (Australia) and Forest Fire applications.
From the above, it can be seen that there is a global opportunity for enhanced performance of wood and
engineered wood products using combined durability and flame retardancy to cover all major treatment
hazard classes in H3, H4, H5 (Australia) and the USA equivalents User Categories (UC-3, UC-4 and UC-5).
The use of durable Flame Retardant [dFR] treated wood products that meet the Australian Standard
(AS3959 - Construction of buildings in Bushfire prone areas, exposed to BAL-29 and BAL-40) is large as it
covers much of Australia’s highly populated states and territories including; Victoria, New South Wales,
South Australia, Australian Capital Territory (ACT) and Western Australia – most of Australia. Currently,
wood and wood engineered products has had little presence in the Bushfire prone areas due to the
limited availability of indigenous hardwoods and the inability to produce a durable Flame Retardant
[dFR] treated product that meets the fire test standards.
The Australian Bushfire market size is approximately AU $400 million per annum and continues to grow
with the expansion of “bushfire prone areas”. The predominant use of radiata pine to manufacture the
durable Flame retardant [dFR] treated wood products is ideally suited as resource (forests) are readily
available in Australia, NZ and Chile. Radiata pine it is a regenerative product, relatively low cost and can
be readily treated and processed using existing plant and equipment. Both the operating and capital
costs to integrate into an existing treatment/wood processing operating is relatively low. The added
value to producing a durable Flame Retardant treated wood product is multi-faceted in terms of
providing value at the forest (feedstock), chemical manufacture, chemical treatment, wood processing
and many more distribution and storage add-ons.
The application for durable Flame Retardant [dFR] wood products includes a wide of outdoor
applications including; decking, fencing, structural bearers/joists, landscape and primed products
including; weatherboards and trim boards. Also there is the application to provide durable Flame
Retardant [dFR] treated wood products into higher retention applications such as fencing, posts and
transmission poles and others
The USA Forest fire market is in excess of US $1.5 billion per annum and continues to grow exponentially.
Similarly, the USA Forest Fire market for the use of durable Flame Retardant [dFR] treated wood
products that meets the relevant USA Standards and could be produced in the same way that the
product is produced for the Australian Bushfire market, as the testing requirements are very similar.
With a durable Flame Retardant [dFR] treated wood and a durable Flame Retardant [dFR] or Flame
Retardant [FR] thermally modified timber (TMT) it is the inorganic metal oxide component that provide
increased fire retardancy to the treated wood.
For ‘Impregnation Modification’ to occur, the impregnant molecules (chemical(s) must be of a
sufficiently small size by which to enter the cell wall (pore diameter less than 5nm). As the wood swells
the void volume (‘micro-pores’) in the cell wall increases which are then filled with liquid chemical(s)
(called ‘working solution’) which fixes chemically via various reaction mechanisms.
From the above, it can be seen that there is a need for an enhanced performance of wood and
engineered wood products (EWP) using varying combinations of wood preservatives (durability) and
flame retardants [FR] or at least provides the public with a useful choice.
Further aspects and advantages of the treatment method or process and wood products thereof will
become apparent from the ensuing description that is given by way of example only.
SUMMARY
Described herein is an enhanced performance of wood and engineered wood products using combined
durability and flame retardancy that comprises several aspects. Firstly, in the product formulation to
produce a durable Flame Retardant [dFR] single phase ‘working solution’ for chemical impregnation.
Secondly, the wood impregnation treatment process and thirdly, the heat (fixation) process which
ensures that the impregnated chemicals are firmly fixed into the wood structure.
In a first aspect there is provided 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 utilises 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.
In a second aspect there is provided a lignocellulosic material product produced by the process of
imparting enhanced durability and fire retardancy properties the lignocellulosic material comprising:
a wood preservative;
a flame retardant [FR], consisting of alkali metal silicates and/or alkali metal aluminates that utilises 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.
Advantages of the above include product formulations that combine wood preservatives (chemicals) and
Flame Retardants [FR] that provide an enhanced durability and flame retardancy required in Bushfire
and Forest Fire prone areas. Flame Retardancy [FR] on its own in outdoor applications has limited value
without having the combined durability of fungal decay (rot) and insect attack (termites). Furthermore,
the product formulations which include the flame retardants [FR] do not in any way impede or hinder
the normal penetration and retention properties of the water borne wood preservatives when applied
using the various treatment processes. Treatment using these formulations meets the appropriate
industry standards for wood preservation. The advantage of this treatment process is that it incorporates
a full impregnation step to achieve both durability and fire retardancy in the treated wood and
engineered wood products. A further advantageous effect of this invention being that treated timber (to
hazard classes H3, H4 and H5) can achieve a level of flame retardancy that will allow it to meet the
Australian Bushfire (AS 3959-2009) and potentially the USA Forest Fire Standards. The treatment process
is versatile as a large range of treated timbers can achieve durable Flame Retardants such as; radiata
pine, pinus elloitti (slash pine), araucaria (hoop pine), douglas fir (oregon pine), pinus carribaea (yellow
pine, yellow southern pine), cedar (western red cedar). Finally, the significance and impact of this
invention is that the durable Flame Retardant [dFR] treated wood product is fully impregnated
throughout the wood substrate making it acceptable for unpainted and painted treated wood products.
Also, the fact that this durable Flame Retardant [dFR] uses a single homogenous ‘working solution’ that
requires a single treatment and heat (fixation) process all of which are able to be achieved in an existing
treatment plant is most advantageous.
BRIEF DESCRIPTION OF THE DRAWINGS
Further aspects of the enhanced performance of wood and engineered wood products (EWP) using
varying combinations of wood preservatives (durability) and flame retardants [FR] will become apparent
from the following description that is given by way of example only and with reference to the
accompanying drawings in which:
Figure 1 illustrates HRR heat curves showing the peak and average HRR values over 1800 sec (30 min.).
In particular, Heat Release Rate (HRR): durable Flame Retardant [dFR] treated wood samples
(FH623925-1/2/3) after Post-Weathering Test (ASTM D2898 Method B modified) and Burn
Test AS/NZS 3837;
Figure 2 illustrates The HRR heat curves showing the peak and average HRR values over 600 sec (10 min.)
versus untreated wood. In particular, Heat Release Rate (HRR): durable Flame Retardant treated
wood samples (FH623925-1/2/3) after Post-Weathering versus Untreated wood samples for
radiata pine;
Figure 3 illustrates the Mass Loss Rate (MLR): mass loss over the duration of the burn test for durable
Flame Retardant [dFR] treated wood samples FH623925-1, 2, and 3 (all completed post-
weathering test ASTM D2898) for radiata pine; and
Figure 4 illustrates a Fire Test Certificate (BRANZ Reference FH10105-001).
DETAILED DESCRIPTION
As noted above, described herein is an enhanced performance of wood and engineered wood products
using combined durability and flame retardancy that comprises several aspects. Firstly, in the product
formulation to produce a durable Flame Retardant [dFR] single phase ‘working solution’ for chemical
impregnation. Secondly, the wood impregnation treatment process and thirdly, the heat (fixation)
process which ensures that the impregnated chemicals are firmly fixed into the wood structure.
For the purposes of this specification, the term ‘about’ or ‘approximately’ and grammatical variations
thereof mean a quantity, level, degree, value, number, frequency, percentage, dimension, size, amount,
weight or length that varies by as much as 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% to a reference
quantity, level, degree, value, number, frequency, percentage, dimension, size, amount, weight or
length.
The term ‘substantially’ or grammatical variations thereof refers to at least about 50%, for example 75%,
85%, 95% or 98%.
The term 'comprise' and grammatical variations thereof shall have an inclusive meaning - i.e. that it will
be taken to mean an inclusion of not only the listed components it directly references, but also other
non-specified components or elements.
The term ‘durable Flame Retardant [dFR] treated wood product’ or grammatical variations thereof refers
the combination of a durable wood (chemical) preservative and a Flame Retardant impregnated into a
wood substrate. A durable Flame Retardant [dFR] treated wood product has achieved a global first in
meeting the Australian Standard (AS 3959-2009 for construction of buildings in bushfire-prone areas) to
withstand exposures up to BAL-29 and BAL-40 conditions (Bushfire Attack Level).
The term ‘enhanced durability’ or grammatical variations thereof refer to resistance to or fungal decay,
rot, insect attack, such as termites and the like.
In a first aspect there is provided a process of imparting enhanced durability and fire retardancy
properties to lignocellulosic material comprising:
a wood preservative;
a flame retardant [FR], consisting of alkali metal silicates and/or alkali metal aluminates that utilises 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.
The product formulations may comprise a durable component and Flame Retardant component which
may combine as a single phase soluble concentrate and should be understood to be termed “working
solution” for chemical (treatment) impregnation. It is in the addition of the combined Flame Retardant
[FR] to the wood preservative in the form of a ‘working solution’ that may be then impregnated into the
wood or alternatively applied in conjunction with a sprayed, immersion or deluge systems.
The durable component may comprise a range of wood preservatives both copper based and non-
copper based to control fungal decay and insect (termite) attack.
The Flame Retardant [FR] component may comprise of a range of inorganic metal oxides which impart
Flame retardancy via various flame retardant mechanisms during fire combustion. Also, the product
formulations may be used in conjunction with Thermally Modified Timber (TMT) and may be the same
product formulations as used with untreated, treated wood and engineered wood products. Also, the
same product formulations may be used as working solutions for treatment impregnation are the same
as may be used for spray, immersion or deluge application systems.
In the case of chemical impregnation the combined wood preservatives and flame retardants [FR] may
be impregnated into the wood substrate and further undergo a heat or drying process to achieve fixation
(non-leaching).
The wood impregnation treatment process may use a wide range of different treatment process
schedules which impart differing performance criteria. The standard conventional wood processing
treatment schedules that may be used, but not be seen as limited to; Bethel, Lowry, Reuping or modified
(low uptake) processes. The inventor has found that all of these processes may be capable of potentially
achieving the required wood impregnation that meets the desired standards for penetration and
retention for chemical durability and fire retardancy. The inventor has found that using chemical
impregnation technology has allowed the facilitation of impregnating the cell wall with a single or
combination of chemicals (wood preservative plus flame retardant), which become “fixed” into the cell
wall of the wood. In the case of durable Flame Retardant [dFR] treated wood products, the modification
is achieved through the addition of inorganic alkali metal oxide flame retardants to a water borne
chemical preservatives (approved for use in H3, H4, H5, UC3A, UC3B, UC4 and UC5) followed via a heat
(fixation) process.
As above, with a durable Flame Retardant [dFR] treated wood or Flame Retardant [FR] thermally
modified timber (TMT), it is the inorganic metal oxide component that may provide increased fire
retardancy to the modified wood.
Without being bound by theory, there are various reaction mechanisms that may occur depending on
the type of flame retardant used; for example alkali metal silicates operate whereby the liquid soluble
silicate monomer may impregnate into the wood voids (cell wall - lumena) as a monomer and on heating
may undergo a condensation reaction (dehydration process) whereby unbound water may polymerise to
produce a longer chain polymeric flame retardant (larger molecule) species. In the case of alkali metal
aluminates, these may operate whereby the liquid (hydrated) stabilised aluminate may impregnate into
the wood voids and on heating may undergo a dehydration process to produce an insoluble aluminate
oxide.
This same chemical impregnation technology as above may also be applied to Thermally Modified
Timber (TMT), where similarly the modification is achieved through the addition of inorganic alkali metal
oxide flame retardant in isolation or in combination with chemical preservatives followed via the
conventional thermal modification heat process (170-230 C) to achieve chemical fixation.
The heat (fixation) process used may be required to fix the combined durable Flame Retardant [dFR]
compounds into the wood or engineered wood products via a range of reaction mechanisms including
but not limited to; dehydration, and/or polymerisation, etc. The heat energy sources may be; kilns,
steam, hot air, and/or radio frequency.
The wood species for the above treatment process may include, but should not be seen as limited to;
radiata pine, pinus elloitti (slash pine), araucaria (hoop pine), douglas fir (oregon pine), pinus carribaea
(yellow pine, yellow southern pine), cedar (western red cedar).
The use of durable fire retardant [dFR] or flame retardant [FR] components can also be applied to other
building construction systems requiring additional Fire Testing including; AS 5637.1:2015 & ISO 9705 (for
internal Wall and Ceiling Linings), ISO 5660 (high rise buildings), AS/NZS 1530.8.1-2007 for fire testing of
building materials, components and structures exposed to simulated bushfire attack e.g. BAL 40 and
engineered wood products.
Technical Problem
The inventor has found to achieve a durable Flame Retardant [dFR] treated wood product, then three
major areas of technical challenge must be identified and resolved.
The Product Formulations used to combine a durable (wood preservative) and a flame retardant
(inorganic metal oxide) as [dFR] must achieve; solution stability (no solution phasing out, no solids
deposition, low viscosity maintained, no gelification), single phase ‘solution concentrate’ that after
repeated pressure-vacuum treatment cycles (charges) remains stable and not affected by soluble wood
extractives, cellulose and lignin species.
The selection of wood preservatives used may be water based in both copper and non-copper active
ingredients. The copper based wood preservatives are approved to H3, H4 and H5 hazard classes while
the non-copper based are H3 approved only.
The Wood Impregnation Treatment Process may use a wide range of different treatment process
schedules which impart differing performance criteria. As above, the standard conventional wood
processing treatment schedules used including Bethel, Lowry, and Reuping all have inherent issues,
hence the technical challenge of achieving a treatment schedule which after repeated pressure-vacuum
treatment cycles (charges) remains stable and not effected by soluble wood extractives, cellulose and
lignin species. The final durable Flame Retardant [dFR] treated wood must achieve the required chemical
impregnation (‘working solution’ uptake – litres/m ) that meets the required standards for penetration
and retention for chemical durability and fire retardancy.
The inventor has found that the Heat (Fixation) Process and the different reaction mechanisms required
to achieve chemical fixation is critically important as potentially any un-fixed chemical will be solubilised
and reduce the performance of both the durable and FR components of the formulation. In the case of
alkali metal silicate Flame Retardants, the smaller size monomeric state of the soluble alkali silicate on
heating (110/80 C) polymerises to a larger species that is insoluble being both chemically and physically
bound within the wood structure. In the case of alkali metal aluminate Flame Retardants, the soluble
alkali aluminate on heating (90/70 C) undergoes dehydration process to produce an insoluble metal
aluminate oxide. The heat energy sources used may be kiln drying.
Solution to Problem
The inventor has unexpectedly found that for the Product Formulation, a wide range of water based
wood preservatives in combinations with varying water soluble alkali metal oxide (Silicates and
Aluminates) based flame retardants were formulated to achieve a stable homogenous durable Flame
Retardant [dFR] working solutions.
Repeated (600-700) ‘screening’ tests of the various durable Flame Retardant [dFR] ‘working solutions’
were conducted using a “Venturi - Filtration Apparatus”. This apparatus may create a vacuum filtration -
70 to-80kpa), whereby the working solutions are passed through a 1-5micron (Qualitative Grade 1.Filter
Paper), where the filtrate rates (measured in seconds /100mls) of the treated flame retardant solutions
are measured against the treated wood preservative (control) solutions. While this method may not
replicate the wood impregnation process it provides an excellent method for ‘pre-screening’ the durable
Flame Retardant [dFR] working solutions. Stability was measured using temperature (ambient to
refrigerated, 30 C to +3 C) , viscosity (digital viscometer), specific gravity (hydrometer), solids deposition
(via filtration), colour change (visual), agitated and non-agitated over time (4-6 months). Once these
working solution met all of the require working solubility criteria, they were taken to the next stage of
wood impregnation process via a treatment plant.
For the Wood Impregnation Treatment Process semi-commercial scale treatment plants were used at
SCION (Rotorua, NZ) and Koppers Performance Chemicals (Wiri, NZ). Chemical treatment could be
carried out on long boards of 2.4 metre length, 150mm wide, and 18 to 45mm thickness covering
virtually all commercial size products. Using the ’full cell’ Bethel cycles during treatment impregnation
process were able achieve uptakes ranging from 550 to 800L/m . However, uptake control in commercial
plants is readily controllable, as these semi-commercial plant operate to time/volume. After treatment
the returned working solution was tested for stability, viscosity, colour, solids, etc., and any other quality
issues that may result from any potential “kickback” attributed to soluble wood extractives, cellulose and
lignin species, however, there were none. Many repeated treatment charges were undertaken. Durable
Flame Retardant [dFR] samples were tested for compliance with chemical penetration (for both wood
preservative and flame retardant) and retention (for copper based wood preservatives only).
The Heat (fixation) Process used Heating Kilns (both large cross-flow and long horizontal kilns) to dry
products on a semi-commercial scale at SCION (Rotorua, NZ). The board drying dimensions being; 2.4
metre length, 100-150mm wide, and 18-45mm thickness covering virtually all commercial sizes used.
In the case of alkali metal silicate Flame Retardants a heating temperature (110/80 C) was used to
polymerise and increase the molecular size whereby ensuring fixation has occurred resulting in non-
leachable durable Flame Retardant [dFR] treated wood product. In the case of alkali metal aluminate
Flame Retardants the soluble alkali aluminate on heating (90/70 C) undergoes dehydration process to
produce an insoluble metal aluminate oxide resulting in non-leachable durable Flame Retardant [dFR]
treated wood product. The heat energy sources used are kiln drying.
The following below describes some preferred embodiments of the invention, in relationship to the
durable Flame Retardant [dFR] product formulation, wood impregnation treatment process, heat
(fixation) process and other applications of spray, immersion or deluge system to provide enhanced
durability and flame retardancy performance of wood and engineered wood products. This invention is
in no way limited to these embodiments as they are purely to exemplify the invention only and that
possible variations and modifications would be readily apparent without departing from the scope of the
invention.
The durable Flame Retardant [dFR] product formulation may consist of a durable component and a
Flame Retardant [FR] component which may combine to produce a single combined formulation that is
further impregnated into the wood and fixed via heat process producing a durable Flame Retardant
[dFR] treated wood product.
The wood impregnation treatment process steps may further comprise:
a) Timber is loaded into the wood treatment chamber (can be cylindrical or square vessel),
then sealed shut;
b) The chamber is then flooded under vacuum (-85kPa) with the various ‘working solutions’,
whereby allowing absorption (chemical uptake, Litres/m ) to occur;
c) Depending on the treatment process used i.e. Bethel, Lowry, Reuping or modified
processes, then various pressures (1300-1500kpa) and vacuum (-85pka) cycles are applied
for 30 to 180 minutes in order to achieve a targeted ‘working solution’ uptake varying from
400 to 800 litres per m ; and
d) Once the timber has been fully impregnated with the required amount of durable Flame
Retardant [dFR], then it progresses to the next Heat (fixation) processing stage.
It should be appreciated by those skilled in the art that the operating parameters stated above are
indicative only, and the full range of these operating parameters are outlined further below.
With regard to the Heat (fixation) process, once the treated flame retardant ‘working solution’ has been
impregnated into the wood (via treatment process), then the wood may undergo a heat (fixation)
treatment process based on time/temperature schedule. The time/temperature schedule is based on a
time range of 24 to 84 hours and a temperature range (input/output) of 130 to 60 C. The
time/temperature range parameters are very critical to optimise chemical fixation and not impair wood
strength.
To evaluate and quantify the effectiveness of chemical fixation process, leachability tests (Leaching Test
EN 84 Method) were conducted on both the wood preservative (dissolved Copper Azole - dCA) and
Flame Retardant (alkali metal silicate). The depletion rate results are outlined in later Examples. Alkali
metal aluminates chemical fixation was measured by chemical retentions calculated after post-
weathering trials (ASTM D2898 method B) and for Flame Retardant measured by the actual burn test
carried out (AS/NZS3837).
In a second aspect there is provided a lignocellulosic material product produced by the process of
imparting enhanced durability and fire retardancy properties the lignocellulosic material comprising:
a wood preservative; and
a flame retardant [FR], consisting of alkali metal silicates and/or alkali metal aluminates that utilises 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.
In the case of chemical impregnation of durable Flame Retardant [dFR] or just a Flame Retardant [FR] to
Thermally Modified Timber [TMT]. After chemical impregnation the [dFR] or [FR] products are placed
into a specific ‘thermal modification heat kiln’ where via a series of process steps reaches an elevated
temperature of at least 190 C and up to 250 C at which point thermal modification has occurred. The
final product being durable Flame Retardant Thermally modified Timber [dFR-TMT] and Flame Retardant
Thermally Modified Timber [FR-TMT].
The embodiments described above may also be said broadly to consist in the parts, elements and
features referred to or indicated in the specification of the application, individually or collectively, and
any or all combinations of any two or more said parts, elements or features.
Further, where specific integers are mentioned herein which have known equivalents in the art to which
the embodiments relate, such known equivalents are deemed to be incorporated herein as of
individually set forth.
WORKING EXAMPLES
The above described enhanced performance of wood and engineered wood products (EWP) using
varying combinations of wood preservatives (durability) and flame retardants [FR] are now described by
reference to specific examples.
EXAMPLE 1
Durable Flame Retardant Chemical formulation
The durable Flame Retardant [dFR] product formulation consists of a durable component and a Flame
Retardant [FR] component which combine to produce a single phase formulation called “working
solution” that is further impregnated into the wood and fixed via heat process producing a durable
Flame Retardant [dFR] treated wood product. The durable and Flame Retardant components are
outlined in below, as is Example 1 and 2 of product formulations.
The durable Flame Retardant chemical formulation comprises:
1. Durable component comprising of a range of wood preservatives used in the control of
fungal decay, mould and insect attack (termites) attack. The range of wood preservatives
extends to both copper and non-copper based formulations, the copper based formulations
include; - Copper Chrome Arsenate (CCA), dissolved Copper Azoles (dCA), micronized
Copper Azoles (mCA), Alkaline Copper Quaternary (ACQ), micronized Copper Quaternary
(mCQ) and the non-copper based formulations include; water based azoles, tri-azoles
including; propiconazole, tebuconazole, cyproconazole and carbamates including;
iodopropynyl Butyl Carbamate (IPBC).
2. Flame retardant component comprising of a range of inorganic metal oxides which impart
flame retardancy via differing flame retardant mechanisms during combustion (fire
burning). The range of inorganic metal oxides includes soluble alkali metal silicates, such as
sodium silicate (ortho, meta, di and tri-silicates), potassium silicate, lithium silicate and
soluble alkali aluminates including sodium aluminate and potassium aluminate. The range
of Flame Retardant [FR] inorganic metal oxides also extends to aluminium oxide nano-
particles (dispersions), aluminium silicate nano-particles (dispersions) and silicon dioxide
nano-particle dispersions.
To best understand the principles of the invention, the following additional working example are
provided for illustrative purposes only.
EXAMPLE 1A. Copper based (durable) Flame Retardant Formulation
28g of sodium aluminate [Na Al O ] is dissolved in a solution of 3g of sodium gluconate (salt of gluconic
2 2 4
acid) and 75g of water to produce a clear and stabilised liquid sodium aluminate solution. Then 2g
dissolved copper azole (9%m/m - Copper, 0.5%m/m - azole) is added to the stabilised sodium aluminate
solution to produce a durable Flame Retardant chemical formulation (working solution), as further
outlined in Table 1. below:
Table 1. Example of a durable Flame Retardant (working solution) below:
Chemical Ingredients % Content Actual Content
Sodium Aluminate [SA] 28% 28g
*Salt of gluconic acid - sodium gluconate 3% 3g
Copper azole (soluble copper azole) 2% 2g
Balance water 67% Balance water
Total 100% 100ml
* Stabiliser agent is salt of gluconic acid (sodium gluconate)
EXAMPLE 1B. Non-Copper based (durable) Flame Retardant Formulation
12.5g of soluble sodium silicate [40% - Na SiO ] is dissolved in a solution of 2g of water based azoles
(Aquazole - PTPm) and 75g of water to produce a milky coloured emulsion. The durable Flame Retardant
chemical formulation (working solution), as further outlined in Table 2. below:
Table 2. Example of a durable Flame Retardant (working solution) below:
Chemical Ingredients % Content Actual Content
Sodium Silicate [SSi] 5% 12.5g
Water Based Azoles
2% 2g
(*Aquazole - 20% Azoles)
Balance water 93% Balance water
Total 100% 100ml
* Aquazole [PTPm]:10%Propiconazole-[P],10%Tebuconazole-[T],5%Permethrin[Pm]
3. The use of aluminium oxide [Al O ] nano-particles (dispersions), aluminium silicate
[Al O3.SiO ] nano-particles (dispersions) and silicon dioxide [SiO ] nano-particle dispersions
2 2 2
as flame retardants components in both water and solvent systems. The nano-particle
dispersions are suspensions of aluminium oxide [Al O ], aluminium silicate [Al 0 .SiO ] and
2 3 2 3 2
silicon dioxide [SiO ] in water or in various organic solvents such as ethanol or mineral oil
and typically range in size of 10-200nm (nano-metres). The range of organic solvents that
can be used with these nano-particle dispersions includes; ethanol, mineral oils and others
including high and low aromatic hydrocarbons and glycols (ethylene and propylene).
4. The use of durable fire retardant [dFR] or flame retardant [FR] components in resin systems
such as glue-line additives (GLA), laminates or compressed. Phenolic resins include; phenol
formaldehyde, urea formaldehyde, resorcinol, melamine urea formaldehyde. Resin system
applications include; plywood, bamboo (laminated and compressed), particle board and
Laminated Veneer Lumber (LVL).
EXAMPLE 2
Wood Impregnation Treatment Process
The preservative treatment of wood by pressure methods is the preferred commercial approach as it
achieves greater efficiency in controlling the conditions and effectiveness in terms of achieving more
uniform, deeper penetration and greater absorption of the working solution. The treatment plant has a
door either at one or both ends to receive the untreated wood (charge), which is then loaded into the
vessel ready for the treatment to occur. The plant has various accessory equipment in known fashion
such as working tanks, flood lines, controls, vacuum and pressure pumps to deliver the various treating
schedules.
There are two types of treatment pressure methods; firstly “empty cell process” where compressed air is
applied to the timber prior to the wood preservative “working solution” is applied. The wood
preservative is added to the vessel from an equalising tank where the air interchanges with the
preservative. By trapping the air in the cells and releasing the pressure after treatment, the trapped air
expands and forces the preservative out, with a final vacuum to remove any further solution. This
process leaves no preservative in cell lumens and recovers much of the preservative used.
The ‘full cell process” uses an initial vacuum removing much of air from the cells, thereby removing the
air cushion which resists preservative penetration. This process achieves the maximum retention of the
chemical preservative in the treatment of the wood.
There is also “modified full-cell process” which is basically the same as the “full-cell process” except that
it uses lower levels of initial vacuum and often uses an extended final vacuum. Modified full-cell process
is the most commonly used method of treating wood with waterborne preservatives.
In wood treatment being ‘Fit for Purpose’ is critical and the various hazard classes or user categories (H3,
H4, H5, or UC3B, UC4B) must meet compliance through penetration and retention. Both penetration and
retention are a function of the treatment process, hence the importance of the correct treatment
schedule for the appropriate wood species, grade and size.
The treatment carried out using the durable Flame Retardant [dCA] can be achieved via ‘full cell process’,
‘modified full cell process’ and ‘low uptake process’ to achieve compliance in terms of penetration and
retention. To achieve the required durability loading (for H3 dCA) and sufficient loading of Flame
Retardancy [FR - kg/m ] needed to meet the heat testing criteria specified by the Australian Bushfire
Standard (AS3959-2009) and the USA ‘Spread of Flames’ testing requirements.
Using non-structural grade (decking) and structural (mgp-10) grade (bearers) radiata pine, which is fully
impregnated using a ‘full cell process’ generates the following chemical uptakes (of working solution)
and retentions for both copper [H3ca] and Flame Retardant [FR] as outlined in Table 3:
Table 3
Impregnation Treatment data for chemical treatment using durable Flame Retardant [dFR - H3ca + alkali
metal aluminate] working solution and showing Chemical Uptake (L/m ) and Retention (kg/m )
Chemical Impregnation Charges
Chemical Retention (kg/m )
Chemical
Sample Wood Type Board Dimensions
Uptake
*Copper Flame Retardant
H3caFx-DA Decking 2.4mx100x22mm 656L/m 1.40 26.2
H3caFx-DB Decking 2.4mx100x22mm 715L/m 1.52 28.6
H3caFx-DC Decking 2.4mx100x22mm 753L/m 1.60 41.4
H3caFx-DD Decking 2.4mx100x22mm 728L/m 1.55 40.0
H3caFx-DE Decking 2.4mx100x22mm 712L/m 1.52 28.5
H3caFx-DF Decking 2.4mx100x22mm 759L/m 1.62 41.7
H3caFx-DG Decking 2.4mx100x22mm 582L/m 1.24 40.7
H3caFx-DH Decking 2.4mx100x45mm 587L/m 1.25 41.1
H3caFx-SA Structural 2.4mx100x45mm 811L/m 1.73 44.6
H3caFx-SB Structural 2.4mx100x45mm 719L/m 1.53 39.6
H3caFx-SC Structural 2.4mx100x45mm 687L/m 1.46 48.1
*Copper H3 retention target 1.1kg/m
Based on these chemical uptakes (L/m ) for both the 22mm and 45mm thickness all of the durable
component - dissolved Copper Azole [dCA] for H3 hazard class meets the required retention of 1.1kg/m
(equivalently if based on a wood density range of 440 to 480kg/m the retention becomes 0.025% to
0.023%m/m Copper). Using lower uptake processes the durable Flame Retardant [dFR] ‘working
solution’ increases to achieve similar or higher retentions as required. Similarly the uptakes for the Flame
Retardant [FR] in this case an alkali metal oxide can be increased to meet the required Flame
Retardancy. Also higher durable component hazard classes can be used i.e. H4 and H5, whereby
increased loadings in the case of soluble copper azole, the loading of H4 increases to 2.0kg/m
(0.42%m/m-Cu), H5 increases to 3.6kg/m (0.76%m/m-Cu), however the FR loadings remain the same.
EXAMPLE 3
Heat (Fixation) Process
Once the treated flame retardant timber has been treated it has a high moisture content (%mc) in the
range 60-200% which requires drying to bring it below 18%mc for resale. It is in the drying process where
various kiln schedules are used in the control of temperature (set points), air flow (fans) and relative
humidity at pre-determined times. The kiln schedules require temperature range for inlet temperature
(wet bulb) to be 60-90 C and the outlet temperature (dry bulb) to be 90-130 C. The time/temperature
schedule is based on a time range of 24 to 84 hours and a temperature range (input/output) of 130 to
60 C. The time/temperature range parameters are very critical to optimise chemical fixation and not
impair wood strength. Other heat sources can potentially be used like steaming, radio frequency and
microwave technology.
In the case of durable Flame Retardant [dFR] - alkali metal silicates [FR] the heat (fixation) process
achieves two important processes in firstly reducing the moisture content (<18%mc) and secondly
provides the energy to activate the condensation reaction mechanism (dehydration process) whereby
the unbounded water molecules in the flame retardant (silicate ions) undergo polymerisation (or partial
polymerisation) to produce a larger and bound molecules within the wood cells. The fixation process is
supported and validated by the leaching test (Leaching Test EN 84 Method) for both the soluble copper
azole and flame retardant (alkali metal silicates), as outlined in Table 4 and 5.
In the case of durable Flame Retardant [dFR] - alkali metal aluminates [FR] the heat (fixation) process
(90/70 C) similarly achieves two important processes in firstly reducing the moisture content (<18%mc)
and secondly undergoes dehydration process to produce an insoluble metal aluminate oxide resulting in
non-leachable durable Flame Retardant [dFR] treated wood product. The fixation process of alkali metal
aluminates is supported and validated by chemical retentions calculated after post-weathering trials
(ASTM D2898 method B) and for Flame Retardant measured by the actual burn test carried out
(AS/NZS3837), refer to Table 6.
To evaluate and quantify the effectiveness of chemical fixation process, leachability tests (Leaching Test
EN 84 Method) were conducted on both the wood preservative (dissolved Copper Azole - dCA) and
Flame Retardant (alkali metal silicate). The depletion rate results are outlined in Example 3. Heat
(Fixation) process Tables 4 and 5. Alkali metal aluminates chemical fixation was measured by chemical
retentions calculated after post-weathering trials (ASTM D2898 method B) and for Flame Retardant
measured by the actual burn test carried out (AS/NZS3837), refer Table 6.
Table 4
Leaching (Fixation): durable Flame Retardant [dFR] with alkali metal silicate shows Copper (wood
preservative, pCu) Loss (depletion) Rate from leaching test method EN84 for radiata pine.
Sample #4 Sample #6 Sample #14 Average
Day 1 0.43% 0.47% 0.54% 0.48%
Day 8 0.43% 0.37% 0.29% 0.36%
Day 14 0.15% 0.18% 0.16% 0.16%
The leaching (leachate solutions) results (samples 4, 6, 14) for copper in the durable Flame Retardant (for
alkali metal silicates) gives an average gradient drop-off rates of 24% at day 1 (0.48%) to day 8 (0.36%)
and 55% drop-off from day 8 (0.36%) to day 14 (0.16%). This copper [Cu] depletion rate is well within an
acceptable level to maintain wood durability for the required hazard classes.
The fixation process for treated wood preservatives such as these copper based fungicides is well
documented.
Table 5
Leaching (Fixation): Flame Retardant (FR) Loss Rate (leaching test method EN84) for radiata pine.
Sample #4 Sample #6 Sample #14 Average
Day 1 1.6% 1.9% 1.0% 1.5%
Day 8 1.1% 1.0% 0.9% 1.0%
Day 14 0.8% 0.9% 0.8% 0.83%
The leaching (leachate solutions) results (samples 4, 6, 14) for Flame Retardant [FR] (for alkali metal
silicates) gives an average gradient drop-off rates of 33% at day 1 (1.5%) to day 8 (1.0%) and 17% drop-
off from day 8 (1.0%) to day 14 (0.83%). This Flame Retardant [FR] depletion rate is well within an
acceptable level to maintain a high level of Flame Retardancy required to contain fire combustion.
LEACHING TEST EN84 METHOD. Leaching Test samples were conditioned in the same way as it had been
done before impregnation (65% RH and 20°C till equilibrium moisture content). Leaching was done
according to EN84. Samples were covered with deionized water in an amount of approximately five
times the volume of the sample and placed in the impregnation vessel. Samples were held in 0.04 bar of
vacuum for 20 min. After vacuum, the samples stayed in the water for 2 hr before the water was
changed for the first time. Specimens were submersed in deionized water for 14 days. From every
sample’s vessel, 5 ml of leaching water was collected, combined and submitted for chemical analyses.
Water changes and collecting of water samples were done ten times.
Table 6 Post - Weathering Chemical Retentions - Copper [Cu] and Flame Retardants [FR] for Alkali Metal
Aluminates
Post – weathering chemical retentions – Copper [Cu] and FR Results
Flame
Copper [Cu] *Target [Cu]
Chemical Uptake -
Test Samples Retardant [FR]
- kg/m (H3) - kg/m
- kg/m
1-HcuFx-WD 759 1.61 41.7 1.10
2-HcuFx-WA 711 1.51 39.1 1.10
3-HcuFx-WC 703 1.50 38.7 1.10
4-HcuFx-WC 753 1.60 41.4 1.10
-HcuFx-WB 728 1.55 40.0 1.10
6-HcuFx-WC 690 1.47 38.0 1.10
7-HcuFx-WB 680 1.45 37.4 1.10
8-HcuFx-WA 587 1.25 32.3 1.10
9-HcuFx-WA 582 1.24 32.0 1.10
-HcuFx-WB 550 1.17 30.3 1.10
*Australian Standard AS1604.1-2012 for Penetration and Retentions
Leaching (Fixation): The chemical leaching results were achieved after the accelerated weathering tests
[this is in accordance with AS 3959-2009, accelerated weathering test method ASTM D2898 method B,
with water flow rate modified to ASTM D2898 Method A]. The Post - Weathering Chemical Retentions
for Copper [Cu] and Flame Retardant [FR – alkali metal aluminate] - refer to Table 6.
The copper [Cu] and Flame Retardant [RF] retentions post-weathering achieve the targeted retention
levels for copper [H3] and the Flame Retardant [FR] retentions as those required to meet the subsequent
burn tests [AS/NZS 3837] required under the Australian Bushfire test in accordance with AS 3959 for
construction in bushfire-prone areas to withstand exposures up to BAL-29 condition. Refer to Figure 4 -
Fire Test Certificate (FH10105-001). The Fire Test Certificate is a global first for achieving a pass for the
use of a “Durable Flame Retardant [FR] treated wood product”.
Reaction Mechanisms - Alkali Metal Aluminates and Alkali Metal Silicates
Alkali Metal Aluminates:
Example: Na Al 0 (solid)
2 2 4
or hydrated as soluble 2NaAl(OH) + heat (90/70 C) = Al 0 (insoluble) + Na 0
4 2 3 2
Alkali Metal Silicates:
Example: Na SiO (solid)
or hydrated as soluble Na O:SiO + heat (120/80 C) = SiO (insoluble) + Na O
2 2 2 2
EXAMPLE 4
Heat Release Rate (HRR)
Under the Australian Bushfire Standard AS 3959-2009 – for construction of buildings in bushfire-prone
areas, it specifies the following:
Appendix F for Bushfire-Resisting Timber (Normative)
F1 GENERAL – Bushfire-resisting timber that is solid, laminated or reconstituted form and is deemed to
be acceptable to withstand exposure up to BAL-29 condition. Timber may be ‘bushfire-resisting’ by
means of one or more of – (a) the inherent properties of the material itself; (b) being impregnated with
fire-retardant chemicals; or (c) the application of fire-resistant coatings or substrates.
F2 TESTING The following applies: (a) to satisfy the requirements for bushfire-resisting timber, timber
shall be tested in accordance with AS/NZS 3837 and shall meet the following criteria:
(i) the maximum heat release rate shall be not greater than 100 kW/m
(ii) the average heat release rate for 10 min. following ignition shall be not greater than 60
kW/m when the material is exposed to an irradiance level of 25 kW/m .
F3 ACCELERATED WEATHERING Where accelerated weathering is required before testing to AS/NZS
3837, external fire-retardant-coated substrates shall be subjected to the ASTM D2898 Method B
weathering regime, with the water flow rate modified to be the same as that within ASTM D2898
Method A.
The key determinant to meet the Australian Bushfire Standard (AS3959) is achieving the required peak
Heat Release Rate (HRR) and average HRR values as outlined under Appendix F. Heat release rate (HRR)
is the rate of heat generation by fire, measured typically kW/m .
The cone calorimeter (located at Branz) will evaluate fire performance properties such as heat release
rate (HRR), fire degradation, time to ignition (Tg), mass loss rate (MLR) and smoke (SEA) Smoke
Extinction Area that calculates the extent of smoke generated during combustion.
Table 7 - Heat Release Rate (HRR) and Mass loss (MLR): for durable Flame Retardant [dFR] alkali metal
aluminates [FH62391/2/3] versus Untreated radiata pine samples [FH57772/3] – also refer
Figures 1, 2 and 3.
FH62391 FH62392 FH62393 FH57772 FH57773
Time
HRR MASS HRR MASS HRR MASS HRR MASS HRR MASS
0 0.51 106.10 -0.94 100.50 -0.84 90.60 4.97 207.10 6.01 84.20
-0.47 106.18 -2.18 100.46 0.12 90.31 5.81 206.65 0.46 83.91
-1.99 105.85 -0.24 100.28 0.14 90.26 0.23 206.57 0.00 83.75
-2.88 105.69 0.40 100.09 0.44 89.95 0.00 206.42 0.00 83.66
40 -2.42 105.57 -1.64 99.97 -1.94 90.09 0.62 206.33 0.00 83.51
50 -1.66 105.48 -2.20 99.80 -2.20 89.95 0.28 206.24 0.00 83.39
60 -0.93 105.31 0.02 99.66 0.29 89.55 0.00 206.11 0.00 83.32
70 -0.88 105.15 0.10 99.48 1.33 89.56 0.00 205.97 0.00 83.17
80 0.37 105.00 -0.68 99.30 1.61 89.37 0.00 205.86 0.00 83.01
90 -0.36 104.84 0.69 99.15 3.11 89.06 0.00 205.69 0.00 82.79
100 0.35 104.59 0.21 98.97 5.20 88.75 1.15 205.42 92.91 81.74
110 1.24 104.43 0.40 98.81 45.84 88.36 123.36 204.30 145.43 80.82
120 1.38 104.19 1.64 98.59 86.69 87.74 156.00 203.28 138.40 79.91
130 1.79 103.95 0.91 98.36 89.12 86.80 129.12 202.45 126.68 79.07
140 2.48 103.66 2.71 98.21 79.72 86.02 106.70 201.74 116.76 78.27
150 4.25 103.33 2.26 97.79 72.70 85.38 96.00 201.10 108.06 77.52
160 3.99 103.05 3.50 97.55 64.28 84.49 86.32 200.49 99.45 76.82
170 4.31 102.70 52.44 96.81 61.54 83.82 80.63 199.93 96.15 76.13
180 40.86 102.20 93.39 95.86 56.83 83.60 74.88 199.43 91.61 75.47
FH62391 FH62392 FH62393 FH57772 FH57773
Time
HRR MASS HRR MASS HRR MASS HRR MASS HRR MASS
190 81.4 101.41 88.61 95.05 52.21 82.65 71.63 198.92 88.63 74.84
200 77.48 100.66 77.69 94.10 48.47 82.13 67.33 198.44 85.63 74.21
210 71.13 99.93 70.96 93.50 44.26 81.67 64.65 197.95 82.13 73.62
220 67.80 99.24 66.39 93.08 39.68 81.28 63.01 197.49 77.20 72.99
230 59.87 98.65 62.11 92.08 35.75 80.88 61.66 197.10 74.12 72.42
240 52.86 98.04 57.95 91.43 30.29 80.46 60.82 196.61 73.32 71.88
250 49.32 97.50 54.83 90.99 24.72 79.73 58.80 196.20 70.26 71.34
260 47.65 96.93 51.67 90.76 20.05 79.36 59.57 195.72 66.72 70.79
270 46.48 96.39 46.01 89.89 20.69 78.96 57.31 195.29 62.91 70.22
280 41.57 95.87 45.24 89.34 23.36 78.74 58.29 194.87 62.01 69.75
290 39.79 95.30 43.37 88.71 23.35 78.28 58.58 194.40 60.48 69.20
300 36.51 94.85 37.23 88.33 21.18 77.49 56.35 193.98 57.58 68.64
310 33.42 94.32 34.46 87.52 22.90 77.01 57.58 193.55 54.65 68.10
320 30.08 93.88 33.02 87.30 22.86 76.96 57.44 193.09 53.86 67.58
330 27.53 93.38 27.75 86.51 23.04 76.39 57.01 192.76 52.40 67.08
340 26.35 92.90 20.94 86.28 22.61 76.04 57.21 192.24 50.51 66.59
350 24.03 92.45 21.68 85.61 22.30 75.44 57.09 191.82 49.34 66.09
360 20.58 91.92 21.84 85.16 23.99 74.95 55.57 191.41 46.59 65.53
370 22.37 91.43 21.93 84.68 20.70 74.31 54.75 190.97 48.82 65.07
380 22.38 91.02 21.72 84.08 22.93 73.82 55.36 190.58 48.22 64.56
390 20.65 90.50 22.24 83.64 22.96 73.40 55.56 190.18 47.63 64.07
400 19.40 90.05 21.16 83.29 23.68 72.91 54.06 189.73 46.70 63.57
410 20.19 89.56 21.93 82.64 24.18 72.65 54.59 189.29 44.28 63.10
420 18.58 89.07 21.48 82.15 25.66 72.36 54.01 188.90 43.27 62.59
430 21.09 88.60 21.82 81.72 24.41 71.91 53.96 188.48 44.76 62.18
FH62391 FH62392 FH62393 FH57772 FH57773
Time
HRR MASS HRR MASS HRR MASS HRR MASS HRR MASS
440 21.05 88.13 24.08 81.15 26.08 71.42 53.82 188.04 44.96 61.68
450 20.10 87.63 23.65 80.79 24.05 71.02 52.49 187.65 44.16 61.18
460 20.69 87.17 22.29 80.36 24.92 70.55 53.42 187.23 44.40 60.70
470 19.90 86.73 22.68 79.71 24.90 70.15 52.66 186.78 44.37 60.27
480 19.15 86.20 22.43 79.24 24.07 69.73 52.64 186.40 44.52 59.79
490 18.52 85.75 22.55 78.75 24.09 68.99 51.81 185.98 43.09 59.30
500 21.66 85.25 23.12 78.37 23.36 68.81 52.32 185.57 43.99 58.84
510 20.96 84.81 23.91 77.74 23.52 68.40 52.06 185.09 43.29 58.42
520 20.01 84.33 25.04 77.16 23.92 67.82 50.61 184.73 44.21 57.94
530 21.08 83.89 24.84 76.84 25.18 67.28 52.22 184.34 44.05 57.46
540 19.04 83.42 25.87 76.28 23.90 67.13 51.38 183.89 42.91 56.96
550 18.67 82.96 24.63 75.51 23.92 66.52 50.09 183.52 46.06 56.54
560 18.32 82.53 24.91 75.17 23.02 66.07 52.55 183.08 45.59 56.07
570 21.20 82.01 24.59 74.90 23.83 65.89 50.04 182.64 43.58 55.63
580 20.05 81.61 23.26 74.35 25.23 65.48 52.18 182.24 43.81 55.19
590 21.52 81.12 23.91 73.89 25.11 64.84 51.71 181.84 46.98 54.70
600 21.22 80.69 24.82 73.27 24.36 64.60 52.93 181.39 46.26 54.22
Table 8. Test Results
The Test Results from HRR (peak and average) and Flame Duration times
FH623925-1 FH623925-2 FH623925-3
*Peak HRR - KW/m 83.4 94.1 93.4
*Average HRR - KW/m 29.1 32.7 31.6
Time to Ignition - Tg 178 sec 166 sec 108 sec
Time to Flameout 352 sec 348 sec 248 sec
Flame Duration 174 sec 182 sec 140 sec
*peak and average HRR test results all pass.
The peak and average HRR test results post weathering and after the burn test pass the required HRR
values of less than 100 kW/m (for peak HRR) and less than 60 kW/m (for average HRR) as outlined
under the Australian Bushfire Standard (AS3959) Appendix F for bushfire-resisting timber.
The achievement of meeting the Bushfire Standard for exposure BAL-29, is the first time that a flame
retardant wood product has achieved this milestone let alone a durable Flame Retardant [dFR] treated
wood product achieving this milestone.
The HRR heat curves showing the peak and average HRR values over 1800 sec (30 min.) is outlined in
Figure 1. Heat Release Rate (HRR): durable Flame Retardant [dFR] treated wood samples (FH623925-
1/2/3) after Post-Weathering Test (ASTM D2898 Method B modified) and Burn Test AS/NZS 3837. (Refer
to Fire Test Certificate – Figure 4)
The HRR heat curves showing the peak and average HRR values over 600 sec (10 min.) versus untreated
wood is outlined in Figure 2. Heat Release Rate (HRR): durable Flame Retardant treated wood samples
(FH623925-1/2/3) after Post-Weathering versus Untreated wood samples for radiata pine – Figure 2.
Burn Test – AS/NZS 3837 (cone calorimeter).
The post-weathering burn test is the most important of all the tests as it establishes the 2 key
determinate peak and average HRR values that MUST be less than 100Kw/m (for peak HRR) and less
than 60 kW/m (for average HRR). All three results must be within a 10% arithmetic mean variance. The
Time to Ignition (Tg) less the Flameout time gives the Flame duration which must be greater than 60
seconds otherwise the igniter is re-inserted.
Flame Retardant [FR] Reaction (Rx) Mechanism
The cone calorimeter test (AS/NZS 3837) used to measure combustion (HRR, Tg, SEA, etc.,) for the
various Flame Retardants impregnated into the wood, operates via varying Reaction (Rx) mechanisms.
The main operating modes of action being; providing heat insulation to the wood, absorb the
surrounding heat or increase the thermal conductivity of wood in order to dissipate the heat from the
wood surface.
The alkali metal silicates [FR] on combustion follows a ‘ceramification’ reaction mechanism, whereby it
creates an insulating blanket which at higher temperatures provides a radiation shield, delaying the
volatilisation of the pyrolysis products and preventing heat from recirculating back into the wood. The
alkali metal silicates have a high heat capacity (‘ceramification’) to contain heat within the wood
substrate, however, as the heat builds up (at the higher temperatures) it gets to point at which energy
(heat) is rapidly released producing elevated peak HRR values. After the peak HRR is reached there is a
rapid decline in HRR, producing a low average HRR value.
The alkali metal aluminates [FR] on combustion follows a ‘hydration’ reaction mechanism, whereby
hydrated soluble form alkali metal aluminate (e.g. 2NaAl(OH) ) acts as a chemical heat sink for the wood
for the wood by absorbing some of the heat of combustion and lowering the temperature near the flame
during endothermic decomposition and as a result, the wood is cooled and the time to ignition (Tg) is
increased. The water vapour released from the hydrated alkali metal aluminate has the effect of diluting
the combustion gases and toxic fumes. The decomposition endothermically releases 35% of its weight as
water vapour which condenses (hydration process) and in process reduces the oxygen content of 21%
down to 13%. The relationship of increasing the concentration of alkali metal aluminate via the hydration
process directly reduces both peak HRR and the average HRR values.
EXAMPLE 5
Mass Loss Rate (MLR)
The thermal decomposition behaviour of the mass loss and mass loss rate (MLR) reflects the combustion
process and is related to the heat release (HRR) and smoke level generated (SEA). The first stage of mass
loss curve is due to the elimination of moisture from the wood, while the second stage (charring) of
thermal decomposition process mostly involves combustion of major wood components, including
cellulose, hemicellulose and lignin. In achieving a successful pass during the cone calorimeter tests
(AS/NZS 3837), the mass loss over the flame duration must exceed 150g/s.m over 60 seconds - refer to
Table 9 below:
Table 9: Mass Loss (calc.) over the flame duration for the durable Flame Retardant [dFR] treated wood
samples (FH623925-1/2/3).
Test Samples (AS3837 Burn test)
FH623925-1 FH623925-1 FH623925-1
Start weight 106.1g 100.5g 90.6g
Less final weight 39.8 38.2g 34.5g
66.3g 62.3g 56.1
Mass loss
(62.5%) (62.0%) (62.0%)
Flame test duration (s,
1558s 1454s 1400s
seconds)
66.3g/1558s 62.3g/1454s 56.1g/1400s
Calc. Mass Loss
2 2 2
= 4.26g/s.m x 60s = 4.28g/s.m x 60s = 4.01g/s.m x 60s
= (g/s.m x 60sec
2 2 2
= 256g/s.m (60s) = 257g/s.m (60s) = 240g/s.m (60s)
2 2 2
Mass loss exceeds >150g/s.m (60s) >150g/s.m (60s) >150g/s.m (60s)
EXAMPLE 6
Smoke Specific Extinction Area (SEA)
A convenient and basic measurement of smoke produced by a given material (e.g. wood) is the Smoke
(Specific) Extinction Area (SEA), measured in m /kg. The relationship between heat release rate (HRR)
and Smoke Extinction Area (SEA) is very important when relating to the influence and survival of humans
(human safety) in a fire. With the Australian Bushfire Standard (AS 3959-2009) smoke generation is not a
criteria for the success, however, with Forest Fires (USA) the smoke generation (measured) is a key
criteria to meeting the fire standards. Included in this specification is reference to smoke generation
(SEA) and the findings of durable Flame Retardant treated wood products versus untreated wood
products.
The SEA value for untreated wood (radiata pine) has an average SEA value of 60m /kg compared to
durable Flame Retardant [dFR] treated woods that have much lower average SEA values ranging from
1.4, 3.5, 12.0 (average 5.6m /kg). Table 10 shows the impact of the Flame Retardant [FR] component
within the durable Flame Retardant treated wood having a significant impact in not only lowering the
heat release rate values, but also reducing the smoke release properties (SEA).
Table 10
Smoke (Specific) Extinction Area (SEA): durable Frame Retardant [dFR] treated wood products versus
untreated wood (radiata pine).
Smoke (Specific) Extinction Area
Products
- SEA (m /kg)
Durable Flame Retardant [dFR] treated wood products (samples)
FH623925-1. 12.0 m /kg
FH623925-2. 3.5 m /kg
FH623925-3. 1.4 m /kg
Total average of all 3 samples 5.6m /kg
Untreated radiata pine 60m /kg
Aspects of the present invention have been described by way of example only and it should be
appreciated that modifications and additions may be made thereto without departing from the scope of
the claims herein.
Claims (25)
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 2 3 2 silicon 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 FH623925-3 0 300 600 900 1200 1500 1800 Time (sec)
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