The use of a warm mixture, based on organic ammonium compound and a phosphonate and a method for treating wood with the same mixture

The invention relates to the use of the warm mixture based on organic ammonium compound and a phosphonate as a flame retardant in a wood.

The invention relates also to a method for preparing a concentrated flame retardant composition comprising liquid or water-soluble organic ammonium compound in combination with a phosphorous containing chelating agent (L), suitable for prevent ing ignition or combustion of the wood. The invention further relates to a method for treating wood at least once by impreg nating, spraying or painting wood with a warm mixture based on organic ammonium compound and phosphonate,

In the JP-patent application 2010-240968 it has been presented a wood preserva tive composition which is based on ammonium carboxylate and active ingredient agent having properties as a flame retardant. However, depending on the concen tration of the active ingredient and the exact formulation of the ammonium carbox ylate, it has now been perceived that the active ingredient agent has a tendency to crystallize out from the liquid. There is also problem of excessive foaming specifi cally when the concentration of the active ingredient agent is high. The purpose of the invention is thus to provide a method and a composition for treating wood, which composition stays as a homogenous solution or dispersion even in a case of presence elevated concentrations of active ingredient having flame retardant properties in wood. This composition should be well absorbed in wood and has good flame retention properties when absorbed or adsorbed therein. The objectives mentioned above have now been achieved by treating wood material with a warm mixture of organic ammonium phosphates. This warm mixture com prises a mixture or reaction product of a monoethanolamine and an organic phos phonate or a choline and an organic phosphonate. pH of this warm mixture of or ganic ammonium phosphates should be between 4-7. To be more accurate, the invention relates to use of a warm mixture, based on or ganic ammonium compound and a phosphonate, which warm mixture is an aqueous solution, which has a temperature in the range of 20 ^° C - 60 ^° C and pH in the range of 4-7 and which comprises, a mixture or a reaction product of a monoethanolamine or a choline and a phosphonate originated from a phosphory containing chelating agent (L). The concentration of said chelating agent (L) is 10-60% w/w, preferably 25-60% w/w from the total weight of said warm mixture, as a flame retardant, in a wood.

The invention also relate to a method for treating wood at least once by impregnat ing, spraying or painting wood with a warm mixture based on organic ammonium compound and phosphonate. Said warm mixture has temperature in the range of 20 ^° C - 60 ^° C and pH 4-7, which warm mixture is an aqueuos solution, emulsion or dispersion, which contains a mixture or a reaction product of a monoethanolamine or a choline and a concentrated liquid solution of a phosphonate originated from a phosphorous containing chelating agent (L).

Additionally the invention relate to method of preparing a concentrated flame retard ant composition comprising liquid or water-soluble organic ammonium compound in combination with a phosphorous containing chelating agent (L), suitable for pre venting ignition or combustion of the wood. The method comprises admixing aque ous solution of monoethanolaminium [NH3CH2CH20H] ⁺ or its salt or cholineamin- ium [N(CH3)3CH2CH2(OH)] ⁺ or its salt, having temperature 20-60 ^° C with an aque ous solution, having temperature 20-60 ^° C and comprising a phosphorous con taining chelating agent (L) or its acid salt in an aqueous solution, wherein phospho rous containing chelating agent (L) comprises 10-70 preferably 25-60% w/w of the said concentrated flame retardant composition.

The phosphorous containing chelating agent (L) is an etidronic acid based bisphos- phonates, specifically 1 -hydroxyethylidene,1 ,1 -diphosphonic acid (HEDP), eth- ylenediaminetetramethylenephosphonic acid (EDTMP) and diethylenetriaimine- pentamethylenephosphonic acid (DTPMP) or salt thereof or a mixture thereof.

The reaction product (phosphate salt) of monoethanolamine or choline and a phos phate based active ingredient having flame retarding properties, which is specifically an organic phosphonate.

Chelation is the formation or presence of two or more separate bindings between a polydentate (multiple bonded) ligand and a single central atom. Usually these lig ands are organic compounds, and are called chelants, chelators, chelating agents, or sequestering agents. Chelating agents are chemicals that form soluble, complex molecules with certain metal ions, inactivating the ions so that they cannot normally react with other elements or ions to produce precipitates or scale. The chelating agent L used for flame retardant agent is a phosphorous containing chelating agent being able to bind iron and manganese ions and that contain phos phorus (P) in the molecular structure such as HEDP. The chelating agent is selected from the group comprising organic phosphonates (i.e. organic phosphonate i.e. or- ganophosphate) preferable HEDP (etidronic acid based bisphosphonates) or a mix ture of chelating agents which belong to two of more groups of phosphonates: 1 - hydroxyethylidene,1 ,1 -diphosphonic acid (HEDP), ethylenediaminetetrameth- ylenephosphonic acid (EDTMP), diethylenetriaiminepentamethylenephosphonic acid (DTPMP) or salt thereof or a mixture thereof.

In the case chelating agent is HEDP, the reaction product is an organic ammonium phosphate which has the formula (1 a) or (1 b) (see below) and it may be formed before, after or at the same time as the wood material has been treated with said warm mixture of organic ammonium phosphates. The chelating agent L can be used in combination with ammonium phosphate of the formula (1 a) or (1 b) ammonium carboxylate of the formula (1 c) or (1 d) as high con centration without precipitation occurring. The concentration of HEDP can be for example up to 25-60% w/w preferable 30-60% w/w in liquid composition compris ing said ammonium carboxylate with formula (1 a) or (1 b) and an active ingredient (HEDP). Usually carboxylate of formula have ammoniur carboxylate 1 :1.

The reaction product of monoethanolamine or choline and chelating agent L (in acid form) is an organic ammonium phosphate. In a case chelating agent is HEDP an organic ammonium phosphate has the formula (1 a) or (1 b):

[HEDP] ^y [NH ₃ CH2CH2(OH)] ^+X (1 a) or

[(HEDP] ^y [N(CH ₃ )3(CH2CH2(OH)] ^+X (1 b) in which y=1 -4, x<= 4y, and x, y are both integers.

The mixture of a monoethanolamine and an organic phosphonate or a choline and an organic phosphonate comprises ionic liquids of monoethanolamine or/and cho- line and aqueous mixtures of monoethanolamine or/and choline. In the ionic liquids monoethanolamine or/and choline these compounds exists mainly as ionic compouds, that is, in their protonated form N(CH3)3 ⁺ (CH2CH2(OH) and N(H ₃ ) ⁺ (CH2CH2(OH) or their salts.

In aqueous mixtures of monoethanolamine or/and choline can also exist in their free form, such as N(H3) ⁺ (CH2CH2(OH). Monoethanolamine or/and choline can also be present in aqueous mixtures as ionic compouds, that is, in their protonated form N(CH ₃ )3 ⁺ (CH2CH2(OH) or N(H ₃ ) ⁺ (OH ₂ OH2(OH) or as their salts X N(H3) ⁺ (CH2CH2(OH) X N(H3) ⁺ (CH2CH2(OH), wherein X means any counter ion for choline or monoethanolammonium ion.

In a case X means phosphor containing chelating agent L, specifically etidronic acid or HEDP acid, compound of the formula (1 a) or (1 b) is an ammonia salt of HEDP acid. This kind of acid salt has some acidic nature left because HEDP acid is neut ralized only partially and its pH remains 4-7.

HEDP can be contacted with aqueous mixtures of monoethanolamine or/and cho line in its acid form (HEDP acid) or free form or its acid salt. Therefore, term HEDP is used herein of the compound HEDP acid or free form of the HEDP.

The term monoethanolamine is used herein of the compound monoethanolamine in free form N(H2)CH2CH2(OH) and its protonated form N(H3) ⁺ (CH2CH2(OH) (that is, monoethanolammonium).

The term choline is used herein of the compound choline in its free form N(CH3)2(CH2CH2(OH) and in its protonated ion compound N(CH3)3 ⁺ (CH2CH2(OH).

Choline is commercially provided usually as its salts, for example as its hydrochlo ride salt where X = Ch

This reaction product is an organic ammonium phosphate salt having flame retard ing properties. It may exists as a liquid or as its aqueous solution. After warm organic ammonium phosphate salt has been brought inside the wood material and water has been evaporated, it may exists as a liquid salt solution or its water complex, even when this organic ammonium phosphate salt solution is cooled to room tem perature or below it. Monoethanolamine or/and choline will prevent organic phos- phonate to crystallize (salting out) from the liquid salt solution.

Both a mixture of a monoethanolamine and an organic phosphonate, or a mixture of choline phosphonate and/or reaction product of a monoethanolamine phosphate (ammonium phosphate), is readily absorbed in very large amounts into wood and is subsequently retained in the wood. Ammonium phosphonate liquid or aqueous so lution should first be heated into an elevated temperature and then wood material is treated with this liquid or aqueous solution.

Liquid or water-soluble organic ammonium phosphate may further comprise organic ammonium carboxylate, in combination with a phosphate based active ingredient having flame retarding properties.

The organic ammonium carboxylate has the formula (1 c) or (1 d):

[NH ₃ CH2(OH)CH ₃ ] ⁺ n [R ⁵ (COO)n]- ⁿ (1 c) or

[N(CH ₃ ) ₃ (CH ₂ (OH)CH ₃ ] ⁺ _n [R ⁵ (COO)n]- ⁿ (1 d) in which R ⁵ is hydrogen, a substituted hydrocarbyl having 1 -6 carbon atoms or an unsubstituted hydrocarbyl having 1 -6 carbon atoms, and n is an integer between 1-6. Such an ammonium carboxylate is readily absorbed in very large amounts into wood and is subsequently retained in the wood. Group R ⁵ in formula (1 ) is preferably hydrogen. The terms "substituted" and "unsubstituted" basically refer to groups con taining heteroatoms (e.g. -OH, -NH2, -COOH).

The mixture of active ingredient and above mentioned ammonium carboxylate is a homogenous liquid solution preferable a homogenous aqueous liquid. The active ingredient contains a chelating agent, that has flame retarding properties.

Group R ⁵ in formula (1 ) is preferably hydrogen. The terms "substituted" and "unsub stituted" refer basically to groups containing heteroatoms (e.g. -OH, -NH2, -COOH). The chelating agent means a chelating agent that contain phosphorus (P) in the molecular structure with a method for treating wood.

The mixture of active ingredient and the above mentioned ammonium carboxylate (1 c) or (1 d), where ammonium ion is based on choline or ethanolamine (that is, is cholineaminium or ethanolaminium) cation, is a homogenous solution or dispersion preferable a homogenous aqueous liquid. The active ingredient contains a chelating agent that has flame retarding properties.

The phosphor containing chelating agent can be used in combination with ethano lamine or choline based ammonium to yield ammonium phosphate of formula (1 a) or (1 b) in high concentrations of phosphor containing chelating agent without any precipitate occurring. This ammonium phosphate may also contain ammonium car- boxylate of formula (1 c) and (1 d).

The ammonium phosphate of formula (1 a) or (1 b) is prepared by mixing monoeth- anolamine or a choline and a phosphonate originated from a phosphorous contain ing chelating agent (L) in an elevated temperature of 20-60 ^° C, preferably 30-60 ^° C to form a warmed aqueous mixture or reaction product and then treating wood ma terial with this heated aqueous mixture or reaction product.

Elevated temperature means herein temperature, which is above room temperature. Suitable elevated temperatures are 30 ^° C, 40 ^° C or 50 ^° C and 60 ^° C.

The concentration of HEDP can be for example up to 70% w/w preferable up to 60% w/w in liquid composition comprising said ammonium carboxylate with formula (1 a) or (1 b) and an active ingredient (HEDP).

Additionally, it has now been found, that instead of mixing ammonium phosphate of formula (1 a) or (1 b) with an active ingredient which is based on above mentioned active ingredient comprising chelating agent L, which contains phosphorus in its molecular structure, one can use also a source of mixture of monoethanolaminium [NH3CH2 CH2(OH)] ⁺ cation or choline [N(CH3)3(CH2CH2(OH)] ⁺ cation with the above chelating agent (chelate) comprising active ingredient acid. Source of monoethano laminium [NH3CH2 CH2(OH)] ⁺ cation or choline [N(CH3)3(CH2CH2(OH)] ⁺ cation can be their common ammonium salt.

The preparation of concentrated compositions, which comprise monoethanolamin ium [NH3CH2CH2(OH)] ⁺ ion or cholineaminium [N(CH3)3(CH2CH2(OH)] ⁺ ion in com bination with the active ingredient comprising chelating agent, which contains phos phorus in its molecular structure, or monoethanolaminium [NH3CH2(OH)CH3] ⁺ or cholineaminium [N(CH3)3(CH2CH2(OH)] ⁺ carboxylate in combination with the active ingredient comprising chelating agent, which contains phosphorus in its molecular structure, should be done in a specific order to avoid precipitation of active ingredi ent.

In the first stage of the present invention source of ammonium (monoethanolamin ium or cholineaminium) is reacted with an active ingredient, comprising phosphorus (P) containing chelating agent, such as an organic bisphosphate (HEDP) acid. pH of the solution should stay between 4-7 preferably 4-6 after this stage. In the second stage the prepared organic ammonium phosphate can then be mixed also with carboxylate R ⁵ (COO)n ion to neutralize source of ammonium (monoeth- anolaminium or cholineaminium) cations totally or partially. The above two-staged reaction is preferable, done in the presence of surfactant such as non-ionic surfac tant.

Such ammonium phosphate is readily absorbed in very large amounts into wood and is subsequently retained in the wood.

In the method for treating wood in accordance with the invention, the organic am monium phosphate of formula (1 a) and (1 b) (monoethanolamiaminium or cholin eaminium chelate)and possible ammonium carboxylate of formula (1 c) or (1 d) with an active ingredient, comprising phosphorus (P) containing chelating agent in its molecular structure, is preferably in the form of an aqueous solution.

Total aqueous composition is then a homogenous aqueous solution (liquid) or dis persion, consisting of ammonium carboxylate or ammonium phosphate, possible additional active ingredients and water, ionic co-solvents, additives and surfactants. The organic ammonium phosphate has a concentration of e.g. y 15-45% w/w of the total composition and the active ingredient (bisphosphate such as HEDP) has a concentration of 10-70 % w/w preferable 25-60 % w/w.

Said active ingredient L is selected from the group comprising 1 -hydroxyethylidene, 1 ,1 -diphosphonic acid (HEDP), ethylenediaminetetramethylenephosphonic acid (EDTMP), diethylenetriaiminepentamethylenephosphonic acid (DTPMP) or salt thereof or a mixture thereof.

Mixing monoethanolaminium or cholineaminium with above mentioned phosphorus (P) containing chelating active ingredient is made preferable in the presence of ionic liquid and water as a solvent. Suitable non-ionic surfactant is also added to ensure forming of a homogenous mixture, such as homogenous aqueous liquid. This com bination can then be later reacted with carboxylate R ⁵ (COO)n but also other acidic anion sources depending on the pH of the final solution are applicable.

Wood treating involves contacting the wood with another substance. Wood treating warm mixture comprises organic ammonium phosphate stands of formula (1 a) or (1 b) for a salt or a complex formed of an ammonium cation and a HEDP acid anion.

Wood treating warm mixture may further comprise ammonium carboxylate of for mula (1 c) or (1 d) wherein carboxylate ion of the salt or complex may be monovalent (RCOO ) or polyvalent (R(COO )n _>i ), and in that case it may also comprise unneut ralised carboxyl groups (-COOH). In the latter case, R ⁵ is defined as being substi tuted with carboxyl.

Since the group R ⁵ is associated with a carboxylate group, the ammonium carbox- ylate of formula (1 ) is preferably based on a lower organic carboxylic acid and it can be prepared from such an acid or its salt. Lower organic acids include lower fatty acids such as formic acid, acetic acid, propionic acid, n- and i-butyric acid, and n- and i-pentanic acid. Useful acids also include benzoic acid and oxycarboxylic acids such as glycolic acid and lactic acid. Lower dicarboxylic acids such as oxalic acid, malonic acid, succinic acid and glutaric acid are also applicable.

Group R ⁵ of formula (1 ) is most advantageously hydrogen, methyl or ethyl. In for mula (1 ), n is preferably 1 or 2, most advantageously 1 . Consequently, the most advantageous organic ammonium carboxylate used in the method of the invention is based on lower fatty acids.

The ammonium ion is primary (RNH3 ⁺ ) or tertiary (RN(CH3), and R is a substituted alkyl containing 1 -6 carbon atoms. Ammonium ions containing substituted alkyls have typically been formed from water-soluble amines, whose alkyl is substituted with one hydroxyl group. Organic ammonium carboxylates with and organic ammo nium phospates of the invention are based on ordinary monoethanolaminium or cholineaminium.

The monoethanolaminium or cholineaminium carboxylate of formula (1 c or 1 d) is selected from the group comprising a salt or a complex of formic acid and monoeth anolaminium or cholineaminium. These agents will provide maximum absorption of the substance into wood and retention in the wood. Preferable organic ammonium carboxylate is a mixture of a salt of formic acid or propionic acid and monoethano- lamine or formic acid or propionic acid and choline.

Active ingredient, which is used in combination with the above mentioned source of ammonium ion (monoethanolaminium of cholineaminium) and source of ammonium carboxylate includes a phosphor containing chelating agent and thus forms a mo noethanolaminium phosphate or cholineaminium phospate . Chelating agent is pref erable, selected from the group comprising phosphonate or bisphosphonate (i.e. organic phosphonate i.e. organophosphate) or a mixture thereof. Thus, chelating agent phosphonate of biphosphonate used herein may have a dual function: it serves as a flame retarding agent and also as a wood-preserving agent. Source of ammonium ions is preferable liquid or aqueous ammonium salt or free alkanolamine or free cholineamine or their mixture.

Chelate means herein an anion of the chelating agent.

In a case active ingredient (chelating agent) is for example HEDP, a homogenous aqueous solution (liquid) comprising combination of monoethanol aminium cation or choline aminium cation and HEDP anion, with the compound of formula (1 a) or (1 b) can be prepared:

X[NH ₃ CH2CH2(OH)] ⁺ + [HEDP]- ^y ®[HEDP] ^y [NH ₃ CH2CH2(OH)] ^+X (1 a)

X[N(CH ₃ ) ₃ (CH ₂ CH2(OH)] ⁺ + [HEDP] ^y ® [(HEDP] ^y [N(CH ₃ ) ₃ (CH ₂ CH2(OH)] ^+x

(1 b) in formulas 1 a and 1 b, monoethanolaminium phosphate (1 a) or cholineaminium phosphate 13b), y=1 - 4, x<= 4y and x, y are both integers and preferable both means 1 .

Monoethanolaminium or cholineaminium phosphates are homogenous aqueous so lutions (liquids) which are prepared in a presence of surfactant, more preferable in the presence of non-ionic surfactant. The compounds (1 a) or (1 b) are made in a presence of water and ionic liquid as a solvent. Suitable surfactant is for example non-ionic surfactant.

Suitable nonionic surfactants are such as alkyl polyglucosides, fatty alcohols in cluding cetyl alcohol and oleyl alcohol, acid or salts of octanoic acid, for example sodium or kalium salts. The latter can be used to reduce crystallization and corro sion. Its kalium and calcium salts can be used for lowering icing temperature of the solution.

The use of tensides i.e. surfactants improves the distribution of monoethanolamine or choline with the mentioned active ingredient containing an anion which is based on phosphonates and facilitates the dissolving of the film forming resins and emul sions based on fatty acids and/or polysaccharides i.e. prevents the phase separa tion in the readymade wood preservative.

Some commonly encountered surfactants of other type include: Anionic surfactants based on sulfate, sulfonate or carboxylate anions such as so dium dodecyl sulfate, ammonium lauryl sulfate, and other alkyl sulfate salts such as sodium laureth sulfate, alkyl benzene sulfonate or fatty acid salts.

Cationic surfactants based on quaternary ammonium cations such as cetylpyri- dinium chloride.

The concentration of phosphor containing active ingredient (chelating agent) in said homogenous solutions or dispersions between monoethanolamine or choline and chelating agent can be kept high without adverse effects.

The mixture of ammonium phosphate of formula (1 a) of (1 b) and chelating agent or monoethanolaminium [NH3(CH2CH20H)] ⁺ or cholineaminium

[N(CH3)3(CH2CH20H)] ⁺ anion and chelating agent can also be contacted with wood by preparing it first from its starting material in situ, in other words substantially in contact with wood. Typical starting materials then comprise hydroxide or a salt (such as chloride) formed by an ammonium ion defined in formula (1 a) or (1 b) (monoeth anolaminium chloride or cholineaminium chloride), and an acid or salt formed by an acid ion of chelating agent, preferable HEDP and/or carboxylate in formula (1 c or 1 d), e.g. sodium salt or ammo, resulting mainly in the following reactions (2a) or (2b):

X[NH ₃ CH2CH2(OH)X] + (HEDPMy) + ® [NH ³ CH2CH2(OH)] ⁺ _x [HEDP-] _y (2a) or

X[N(CH3) ₃ (CH2CH20H)X] + (HEDPMy) + ® [(N(CH3) ₃ (CH2CH20H)] ⁺ _n [HEDP ] _y (2b)

And when ammonia carboxylate is also made in situ in the same time:

X[NH ₃ CH2CH2(OH)X] + (HEDPMy) + R ⁵ (COOM) _m ® [NH ³ OH ₂ OH ₂ (OH)] ⁺ _c [HEDP ] _y [R ⁵ (COO)m]- (2c) or

X[N(CH3)3(CH2CH ₂ OH)X] + (HEDPMy) + R ⁵ (COOM) _n ® [(N(CH3) ₃ (CH2CH20H)] ⁺ _n [HEDP-] _y [R ⁵ (COO)n]- (2d) in which carboxylates of formula (2a) and (2b) are stable, y, x and n are integer, y is between 1 - 4 and y+m<=5x, R ⁵ is identical to those of formula (1 c) and (1 d) and X and M are an anion respectively a cation forming a stable acid or salt. Typical anions X comprise hydroxyl and halogenides for example chloride and typical cation M comprise proton and alkali and earth alkali metals.

In the practice, formulas (2a) and (2b) are prepared e.g. by mixing an ammonium cation source and a phosphor containing chelating agent as a anion source in the desired molar ratio, either without a medium or by using an appropriate solvent such as water or water and ionic solvent as a medium. During the reaction, the mixture is heated gently into temperature 20 ^° C - 60 ^° C, preferably 30 ^° C - 50 ^° C. After or during this reaction possible source of carboxylate is added while maintaining tem perature at 20 ^° C - 60 °C.

When the starting material is an ammonia source (monoethanol amine or choline) amine and an etidronic acid, they are simply mixed during gentle heating.

When the starting materials consist of salts, that is a) salts of monoethanol amine or choline and b) acid salts of HEDP, these salts a) and b) are typically dissolved separately in water, and then the solutions are combined while heating at the same time. When both the starting materials and the formed product are hydrophobic, the preparation can be carried out in an organic solvent instead of water.

Preliminary results indicate, that when ammonium carboxylate of formula (1 c) or (1 d) is for instance a fluid pair: ethylene amine - formic acid, it can under special circumstances react and form amide when no solvent is present. Increasing tem perature favours amide formation. Nearly no esters are formed.

It has now been found that the organic ammonium phosphate (1 a) or (1 b), for ex ample ethanolamine 1 -hydroxyethylidene,1 ,1 -diphosphonate or choline 1 -hydroxy- ethylidene, 1 ,1 -diphosphonate is also suitable for transferring a wood preservative active ingredient into the wood that contains phosphorous chelating agent(s) se lected from the group comprising 1 -hydroxyethylidene,1 ,1 -diphosphonic acid (HEDP), ethylenediaminetetramethylenephosphonic acid (EDTMP), diethylene- triaiminepentamethylenephosphonic acid (DTPMP) or salt thereof or a mixture thereof which provides wood properties against flammability of wood. Said active ingredient can be also a mixture or a reaction product of an organic active ingredient salt and an organic active ingredient acid.

The invention is based partly on the fact, that both polar poles of monoethanolamine or choline present in formula (1 a) or (1 b) or ammonium carboxylate of formula (1 c) or (1 d) present in the ethanolamine phosphonate / carboxylate or choline phospho- nate/carboxylate are readily adsorbed and absorbed to the treated wooden material. The small molecular size of the both polar molecules, the low surface tension and the special feature of both polar molecules to fasten in the hydrofobic and hydrofilic materials, components and molecules of the wood makes the organic ammonium carboxylate extremely effective in the use of wood treatment.

The wooden material can easily be treated with the heated mixture of organic phos phate or organic phosphate/carboxylate. This heated mixture may contain phos phate anions (HEDP acid) and/or ethanolaminium or cholineaminium phosphate and organic carboxylate phosphate anions and will stay inside the wooden material without leaching out even when the mixture has cooled.

In the same time solutions comprising organic ammonium phosphate of formula (1 a) and (1 b). Ammonium cation is ethanolaminium or cholineaminium cation and an active ingredient anion is based on phosphonic acid, selected from the group com prising 1 -hydroxyethylidene,1 ,1 -diphosphonic acid (HEDP), ethylenediaminetetra- methylenephosphonic acid (EDTMP), diethylenetriaiminepentameth- ylenephosphonic acid (DTPMP) or salt thereof or a mixture thereof do not have any tendency to form precipitates or to foam.

When wood is treated with the heated solution comprising ethanolaminium or cho lineaminium phosphate which may comprise also ethanolaminium or cholineamin ium carboxylate, active ingredient is preferable based on phosphonic acid or biphos- phonic acid, selected from the group comprising 1 -hydroxyethylidene, 1 ,1 -diphos- phonic acid (HEDP), ethylenediaminetetramethylenephosphonic acid (EDTMP), di- ethylenetriaiminepentamethylenephosphonic acid (DTPMP) or salt thereof or a mix ture thereof. This have a flame retardant wood material becomes non-flammable or get better properties against fire (fire protection).

Wood can be treated in sufficiently large amounts with solution containing men tioned chelating agents because these chelating agents are not toxic. Additionally using the concentrated solutions of phosphor containing chelating agents and wood preservative solutions one can achieve excellent fire protective properties and wood preservative on wood material.

Since the organic ammonium carboxylate and corresponding ammonium phosphate is well absorbed into wood, it can, in another embodiment, be used as a further carrier of other active ingredients, such as active ingredients protecting the wood from micro-organisms.

Since the ethanolamine or choline phosphate and carboxylate are well absorbed into wood, they can, in another embodiment, be used as a carrier of other kind of active ingredients, such as active ingredients protecting the wood from micro-organ isms. The carrier then dissolves the active ingredient, transfers it in large amounts into the wood, and retains it in the wood. Consequently, the quality and quantity of the ammonium cation under consideration can be selected so that it transfers the wood-preservative agent to the wood.

It has been found that the organic ammonium carboxylate of formula (1 c) or (1 d) is particularly suitable for transferring wood preservative into wood comprising also a microbicide wood preservative. Microbicide wood preservative is preferable a mix ture or a reaction product of an organic active ingredient salt and an organic active ingredient acid.

The microbicide organic active ingredient salt component of the active ingredient is preferably selected from the group comprising alkali metal, earth alkali metal and ammonium salts of aromatic acids, alkali metal, earth alkali metal and ammonium salts of aliphatic and aromatic sulphonic acids and acid salts of amines.

Particularly advantageous organic active ingredient salts comprise chelating agent such as EDTA or salt thereof or a mixture thereof containing sodium benzoate, so dium alkyl benzene sulphonate, cetyl pyridinium chloride and a salt of formic acid and ethanolamine. The latter also acts as a well absorbable organic ammonium carboxylate according to formula (1 c) or (1 d).

The organic active ingredient acid component of the active ingredient used for pro tecting wood from micro-organisms is preferably selected from the group comprising aromatic carboxylic and sulphonic acids, fatty acids, organic hydroxylic acids and their oligomers and chelating acids.

Preferred substances comprise benzoic acid, and ethylenediaminetetraacetic acid (EDTA). A mixture of benzoic acid and a C12-C18 fatty acid such as stearic acid is a particularly advantageous organic active ingredient component.

An advantageous combination is organic active ingredient acid and organic ingredi ent salt/ammonium HEDP + salt of ethanolaminium together with formic acid and/or propionic acid. In one embodiment of the invention, wood is treated with a view to protect it also from micro-organisms. In that case, the organic ammonium carboxylate of formula (1 c) or (1 d) may act as a wood preservative, with its quality and quantity selected so as to protect the wood from micro-organisms. In an aqueous solution, the weight ratio of organic ammonium carboxylate of formula (1 c) or (1 d) to water is then par ticularly in the range of 1 :6-1 :1 . In this embodiment, the wood preservative contains typically 15-45% by weight of the agent of formula (1 c) or (1 db).

Given the exceptionally good absorption into wood and retention in wood, one em bodiment of the invention does not require environmentally hazardous copper and/or zinc to be included in the aqueous solution.

Some microbicide organic active ingredients mentioned above can be used in other purposes also. For example, they can be used as surfactants (sodium alkyl benzene sulphonate and benzalkonium chloride).

In one embodiment, the ethanolamine or choline phosphate of formula (1 a) or (1 b) phosphate is used for transferring other substances into the wood as well. Typically such substances comprise anti-oxidants, free-radical capturers, UV protective agents and wood extractives, such as tannins, described in WO 2009/101261 or WO 2009/101262 for Granula Ltd which WO-publications will be incorporated therein completely.

Wood is treated by a heated mixture (solution) solution of ethanolaminium or cho- lineaminium carboxylate of formula (1 c) or (1 d) and ethanolaminium or cholineamin- ium phosphate of formula (1 a) or (1 b) in combination with organic active ingredient (microbicide) as mentioned above in such a way that said solution is adsorbed and absorbed to the wood to be treated over the whole thickness thereof, or to a certain depth from the surface.

Since various alternatives exist, the treatment may be carried out during processing of wood at suitable point, for instance during the final drying of the wood.

The wood treatment solution (mixture) of the invention is heated and an elevated temperature is used in the process, thus further improving the adsorption and ab sorption.

The invention enables a convenient procedure for the treatment of wood materials in a cost effective manner, said procedure being easily incorporated into other com mon processes as one stage in the process line comprising successive steps for the treatment of wood product or articles for example first step using the pressure im pregnation and the second step using spraying, painting or other surface treatment process by impregnating the wood with this agent or an aqueous solution of it under vacuum. The typical impregnating period is 1 -120 minutes and the typical treatment temperature is 80-160 °C. After impregnation, the wood is usually rinsed.

The invention also relates to a wood preservative composition, which provides also fire protection to wood. The composition contains organic ammonium carboxylate and an organic active ingredient containing a chelating agent, which is HEDP that gives wood fire retention properties. The organic ammonium phosphate or mixture of ammonium phosphate and ammonium carboxylate /phosphate has the formula:

X[NH ₃ CH2CH20H] ⁺ + [HEDP]- ^y ®[ HEDP] ^y [NH3CH2CH2OH (1 a) or

X[N(CH3) ₃ (CH2CH20H)] ⁺ + [HEDP] ^y ® [(HEDP] ^y [N(CH3) ₃ (CH2CH20H)] ^+X

(1 b); or

X[NH ₃ CH ₂ CH2(OH)X] + (HEDPMy) + R ⁵ (COOM) _m ® [NH ³ OH ₂ OH ₂ (OH)] ⁺ _c [HEDP ] _y [R ⁵ (COO)m]- (3a), or

X[N(CH3) ₃ (CH ₂ CH ₂ OH)X] + (HEDPMy) + R ⁵ (COOM) _n [(N(CH3) ₃ (CH2CH ₂ OH] ⁺ _n [HEDP-] _y [R ⁵ (COO)n]- (3b). in which R ⁵ is hydrogen, a substituted hydrocarbyl having 1 -6 carbon atoms or an unsubstituted hydrocarbyl having 1 -6 carbon atoms, and y, x and n are integer, y is between 1 -4 and y+m<=5x, n and m are between 1 -6. R ⁵ is identical to those of formula (1 a) and (1 b) and X and M are an anion r and a cation forming a stable acid or salt. Typical anions X comprise hydroxyl and halogenides, for example choloride and typical cations M comprise proton and alkali and earth alkali metals.

Active ingredient is selected from the group comprising a phosphonate or a bisphos- phonate or salt thereof or a mixture of chelating agents selected from the group comprising 1 -hydroxyethylidene,1 ,1 -diphosphonic acid (HEDP), ethylenedia- minetetramethylenephosphonic acid (EDTMP), diethylenetriaiminepentameth- ylenephosphonic acid (DTPMP) or salt thereof or a mixture thereof.

The wood preservative composition in accordance with the invention thus contains the same organic ammonium carboxylate of formula (1 a) and (1 b) and/or the same active ingredient that gives wood fire protection and which are used in the wood preparation method described above. Hence, the technical special features above relating to the organic ammonium carboxylate in combination with active ingredient and their composition also apply to the wood preservative composition of the inven tion. For this reason, only a number of crucial features of the composition will be repeated below.

In the organic ammonium carboxylate of formula (1 c) and (1 d) in the wood preserv ative composition, R ⁵ is preferably hydrogen, methyl or ethyl. R ¹ is preferably hy drogen.

The active ingredient (chelating agent) gives flame retarding properties to ammo nium phosphate of formula (1 c) or (1 d). Typical chelating agents of this kind are 1 - hydroxyethylidene,1 ,1 -diphosphonic acid (HEDP), ethylenediaminetetrameth- ylenephosphonic acid (EDTMP) or diethylenetriaiminepentamethylenephosphonic acid (DTPMP) or a mixture thereof.

The organic ammonium phosphate of formula (1 a) or (1 b) is typically in the form of an aqueous solution having typically a concentration of 20-88 % by weight from total composition comprising ammonium phosphate of formula (1 a or 1 b) and wood preservative composition containing Hedp or HEDP acid for protecting wood from flames.

The HEDP containing wood preservative solution against flames is preferably in a form of an aqueous solution or dispersion having an active ingredient concentration of 10-70 %, preferable 25-60 % by weigh and ammonium ion source (choline or MEA (monoethanolamine)) concentration of 10-50 % by weight. This kind of aque ous wood preservative solution can contain also surfactans and additives including other kind of active ingredients, viscosity modifiers, biocides, colouring agents, UV- protecting substances, agents modifying water repellency of composition, stability enhancers etc.

Surfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension in between two liquids. A surfac tant can be classified by the presence of formally charged groups in its head. A non ionic surfactant has no charge groups in its head. The head of an ionic surfactant carries a net charge. If the charge is negative, the surfactant is more specifically called anionic; if the charge is positive, it is called cationic. If a surfactant contains a head with two oppositely charged groups, it is termed zwitterionic. Instead of sodium alkyl benzene sulphonate can be used other surfactants also de pending on the composition to be prepared. The use of tensides, i.e. surfactants, further improves the distribution and the penetration of the organic ammonium car- boxylates of formula (1 ) and the wood preservative active ingredients and facilitates the dissolving of the film forming resins and emulsions based on fatty acids and/or polysaccharides i.e. prevents the phase separation in the readymade wood preserv ative.

Some commonly encountered surfactants of each type include anionic based on sulfate, sulfonate or carboxylate anions, such as sodium dodecyl sulfate, ammo nium lauryl sulfate, and other alkyl sulfate salts such as sodium laureth sulfate, al kyl benzene sulfonate or fatty acid salts; cationic based on quaternary ammonium cations such as cetylpyridinium chloride; nonionic such as alkyl polyglucosides, fatty alcohols including cetyl alcohol and oleyl alcohol, acid or salts of octanoic acid, for example sodium or kalium salts. The latter can be used to reduce crystal lization and corrosion.

The wood preservative composition according to invention can also include one or several microbisides as additives.

The organic ammonium carboxylate or phosphate may act alone in the composition or together with another microbicide wood preservative compound as a microbicide, protecting wood additionally for microbes.

A microbicide wood preservative compound comprises preferably microbicide active ingredient that is a mixture or a reaction product of an organic active ingredient salt and an organic active ingredient acid. The organic active ingredient salt is typically sodium benzoate, sodium alkyl benzene sulphonate, cetyl pyridinium chloride, a salt of formic acid and ethanolamine, or a mixture of these. The organic active ingredient acid is typically benzoic acid, stearic acid, ethylenediaminetetraacetic acid (EDTA) or a mixture of these.

From biocides we wish especially mention PHMG, which can be added preferably 0.001 -5 wt-% to the wood preservative composition according to invention for en hance the protection against molds. Further, the drying properties of PFIMG are very good which speeds up the treating process. Other polymeric guanidines or poly meric compounds can also be included into wood preservative composition. Paint type resins such as fatty acids and/or polysaccharides may be added into wood preservative compositions of invention to further improve the water-repellency of wood material.

0.005-7 wt-% of tensides may be added to the wood preservative compositions to further improve stability thereof or to further facilitate adsorption and absorption of a wood preservative composition into wood.

The invention also relates to the use of the composition described above for prepar ing wood by impregnating the wood with this composition. It has also been surpris ingly found that the ammonium carboxylate or phosphate of the invention can be used either as such or together with known anti-corrosive agents for making wood corrosion-free, less corrosive or anti-corrosive. After preparation, the wood will pre vent or reduce corrosion of metal bodies such as nails, screws or the like getting into contact with the wood.

The inventors have found that the ammonium phosphate of formula (1 a) or (1 b)

X[NH ₃ CH2CH2(OH)] ⁺ + [HEDP]- ^y ®[ HEDP] ^y [NH ₃ CH2CH2(OH)] ^+X (2a)

X[N(CH3) ₃ (CH2CH ₂ OH)] ⁺ + [HEDP] ^y ® [(HEDP] ^y [N(CH3) ₃ (CH2CH ₂ OH)] ^+x

(2b) in which y=1 -4, x<= 4y when x, y are both integers as such has wood protecting properties against fire.

The objectives mentioned above have now been achieved with a new method for preparing wood with liquid or water-soluble organic ammonium carboxylate of the type above, in combination with an active ingredient having flame retarding proper ties.

Also the organic ammonium carboxylate, having the formula (1 c) or (1 d) in combi nation with an active ingredient selected from the group comprising phosphonates (i.e. organic phosphonate, i.e. organophosphate) preferable HEDP (etidrone acid based bisphosphonates), or a mixture of chelating agents, which belong to two of more groups of phosphonates: 1 -hydroxyethylidene, 1 ,1 -diphosphonic acid (HEDP), ethylenediaminetetramethylenephosphonic acid (EDTMP), diethylenetriaimine- pentamethylenephosphonic acid (DTPMP) or salt thereof or a mixture thereof have flame retarding properties. [NH ₃ CH2CH2(OH)] ⁺ _n [R ⁵ (COO)n]- ⁿ (1 a) or

[N(CH ₃ )3(CH2(CH2(OH)] ⁺ n [R ⁵ (COO)n]- ⁿ (1 b) in which R ⁵ is hydrogen, a substituted hydrocarbyl having 1-6 carbon atoms or an unsubstituted hydrocarbyl having 1-6 carbon atoms, and n is an integer between 1-6. Such an ammonium carboxylate is readily absorbed in very large amounts into wood and is subsequently retained in the wood. Group R ⁵ in formula (1 ) is preferably hydrogen. The terms "substituted" and "unsubstituted" refer basically to groups con taining heteroatoms (e.g. -OH, -NH2, -COOH).

Depending on the application, ammonium carboxylate or ammonium phosphate can be as a solid form or as a solution. Preferably, ammonium carboxylate of formula (1 a) or (1 b) is used as a solution for treating wood material. The preferable structure and properties of ammonium ion [NH ₃ CH2CH2(OH)] ⁺ _n or [N(CH3) ₃ (CH2)20H)] ⁺ and acid ion [R ⁵ (COO)n] ⁿ in formula (1 a) and (1 b) have been discussed extensively above and therefore it is not our intention to repeat them in this connection. Wood is treated by a solution of ammonium phosphate of formula (1 a) or (1 b) in such a way that said solution is adsorbed and absorbed to the wood to be treated over the whole thickness thereof, or to a certain depth from the surface. The ab sorbing and adsorbing properties of ammonium phosphate, and also, the general methods for preparing ammonium phosphate solutions has discussed extensively above. Under the heading“Examples” we will give thereinafter some established methods for impregnating, spraying and painting wood material with solutions which is also applicable when used ammonium carboxylate containing solutions as such.

If ammonium phosphate of formula (1 a or 1 b) is used as a solution, it is prepared as described above that is, by mixing an ammonium cation source and a phosphate anion source in the desired molar ratio, by heating and either without a medium or by using an appropriate solvent such as water as a medium.

When ammonium phosphate of formula (1 ) is used as a liquid solution, it may be in a form of ionic solution when the amount of water is very small (1 -5 % w/w of water). Ionic solution it is preferably a mixture of salt comprising a suitable molar ratio of salt of an ammonium component present in formula (1 a or 1 b ) mixed with suitable amount of moles of salt of an acid component present in formula (1 a or 1 b).

The non-flammability properties of ammonium carboxylate of formula (1 a) or (1 b) can be enhanced by using a mixture of liquid or water-soluble organic ammonium carboxylate of formula (1 c) or (1 d) and an active ingredient comprising chelating agents mentioned above.

Examples

A number of examples are given below with the sole purpose of illuminating the invention.

Example 1

Compositions and their usage

A typical aqueous solution contains 8-45 % by weight preferable 25-45 by weight of HEDP (HEDP and/or HEDP acid). HEDP is able to bind iron and manganese ions and it contain phosphorus (P) in its molecular structure. This solution contains addi tionally ammonium carboxylate 1 -30 % by weight and possible wood preservative containing active ingredient 1 ^45 % by weight, the remainder being substantially water, additives and surfactants.

Composition 1

Composition 1 is targeted to fire-protection of wood. Composition 1 protects wood against fire and it makes wood non-flammable for a certain time.

30 wt-% monoethanolammonium formiate (43 wt-% formic acid and 57 wt-% mo- noethanolamine)

8.33 wt-% Cublen KT600 (60 wt-% HEDP)

0.5 wt-% PHMG 20 (20 wt-% PHMG)

Cublen is neutralized with monoethanolamine in aqueous environment.

1-4 wt-% non- ionic tenside

rest is water

The composition of example 1 was well absorbed and adsorbed into wood and has excellent fixation into wood material.

Composition 2

Composition 2 is also intended for protecting wood against fire and makes wood non-flammable for a certain time. 10 wt-% monoethanolammonium formiate (43 wt-% formic acid and 57 wt-% mo- noethanolamine)

49.2 wt -% Cublen KT 600 (29.5 wt-% HEDP)

20.6 wt-% ammonia water (24.5 wt%) i.e. ammonia (100%)

3.6 wt-% ionic tenside

rest is water

The composition 2 was applied onto surface of plywood board made of spruce or birch. The composition was absorbed well into wood, about 250 g/m ² when applied once. Treated wood material showed excellent fire-protecting properties in a test according to standard EN5660.

The composition of example 2 was well absorbed and adsorbed into wood and has excellent fixation into wood material. The compositions 1 and 2 can be used for impregnating, painting or spraying wood as described below.

Depending on the specific application and wood treating method, the compositions according to invention can be modified very extensively as to their ammonium car- boxylate and chelating agent content compared to those prepared in example 1 or 2. For example, if one uses composition according to example 2 and impregnates wood with this composition, it may be possible to lower then amount of chelating agent to about 1 /20 from concentration shown in example 1 or 2.

The chelating agent 1 - hydroxyethylidene,1 ,1 -diphosphonic acid (HEDP) used in compositions 1 and 2 can be replaced by other phosphor containing chelating agents such as ethylenediaminetetramethylenephosphonic acid (EDTMP) or dieth- ylenetriaiminepentamethylenephosphonic acid (DTPMP).

Composition 3

Concentrated homogenous solution

53% HEDP acid (60 %) = 31 .8 % w/w calculated from the total weight of the com position 3.

25 % of ammonia water (24.5 %) = 6.1 % w/w NH3

Total weight of HEDP and ammonia water: 37.9 % w/w calculated from the total weight of the composition 3. Composition 4

Concentrated homogenous dispersion

50 % HEDP (70 %) = 37.9 % w/w calculated from the total weight of the composition 4. 50 % complex of formic acid and monoethanolaminium + non-ionic surfactant (37.9

% w/w)

Total weight of HEDP and dispersion containing complex of formic acid and mo- noethanolamine ammonia water: 53.9 % w/w calculated from the total weight of the composition 4. Composition s

Ammonium phosphate +HEDP (FR3)

The following aqueous solutions were mixed in elevated temperature of 30-60 ^° C

-50 % of aqueous solution, which contains HEDP acid (60 %) and 12.5 % ammonia water. Total solids was 37.9 -50 % aqueous solution, which contains monoethanolamine 29 % + HEDP acid 41

%. Total solids was 70 %.

Solids content was 53.9 % for this aqueuos solution, which contains monoethano laminium salt of HEDP, water and ammonia neutralized HEDP.

FR3 is a relatively high viscous fluid at room temperature. Viscosity can be in- creased by increasing the temperature over ca. 40°C. The higher the amount of HEDP in the FR3 is a) the higher the solid content is, and b) the better the fire retardant properties are, and c) the lower is the leaching of the fire retardant out of the veneer in water exposure conditions.

Examples 2-4 In the following, practical examples will be given of methods how compositions ac cording to invention can be used for the treatment of wood and how the treatment can be integrated in a wood material processing line in mills for wood processing. 2) Immersion impregnation

The most preferable in the immersion impregnation in elevated temperature. Pene trability of the composition according to the invention is good, and in some cases, mere immersion impregnation is also possible. This method is simple but it requires separate immersion basins and is carried out in batch processes, like the pressure impregnation. This method is carried out at elevated temperature of 20-60 ^° C.

3) Drying of the wood and the control of final moisture content

In the processing of timber in sawmills, it is more and more important that the final moisture content of the wood is suitable to prevent cracking and dimensional changes, as well as to prevent too good a substrate from forming for biological life. In connection with the drying, the tree often dries to a moisture content that is lower than desired. At the end, the moisture content can be adjusted, for example, by a technique based on spraying with water. In this step, it is very easy to add the com position according to the invention into the wood, wherein it is possible to eliminate cracking and dimensional changes due to the drying of wood. Furthermore, this method can be used to improve the fire resistance and to provide at least a short term preservation against micro-organisms.

In connection with the treatment methods according to points 1 to 4, however, it is important to dry the wood well (for example, at a temperature from 40 to 80 ^° C), wherein the extra water absorbed in the wood during the process can be removed and the moisture content can be stabilized to a desired final level.

By the solution of the invention, it possible to facilitate the treatment of wood under winter conditions where the processing of frozen wood (for example, melting, im pregnation, planning, painting, etc.) is problematic and constitutes an extra cost item.

Usually ammonium carboxylate of composition 1 -formula (1 ) or mixture of ammo nium carboxylate and ammonium phosphate (composition as mentioned above is absorbed into wood by impregnating the wood with this agent or an aqueous solu tion of it under vacuum. The typical impregnating period is 1-120 minutes and the typical treatment temperature is 80-160°C. After impregnation, the wood is usually rinsed. Example 4

In the following are given exemplary microbiside active ingredients, which can be also used in compositions and solutions containing above mentioned chelating agents which repels invertebrates. The ammonium carboxylate carriers mentioned in connection of those microbicide active ingredients may also be used when pre paring above mentioned chelating agents.

Microbicide studies

Objective

Studies are made in order to determine the microbicide effect of the system com- bining an ammonium carboxylate carrier and an active ingredient of the invention against micro-organisms that damage wood (mildews and blue stain and rot fun gus).

1. Materials and methods

1.1 Ammonium carboxylate carriers Two ammonium carboxylate carrier mixtures were selected for the tests, with the water-soluble mixtures selected as shown in the accompanying table (table 1 ). A White Spirit solvent was additionally used as a reference carrier.

Table 1 Ammonium carboxylate carriers selected for the tests.

MH = formic acid (actually its anion, i.e. formiate)

EA = ethanolamine (actually its cation, i.e. ethanolammonium)

PH = propionic acid (actually its anion, i.e. propionate)

2.2 Active ingredients and their mixtures The active ingredients under study consisted of the commercial and new solutions listed in the central column of the following tables (2 and 3). The right-hand column of the tables corresponds to the ammonium carboxylate solutions used in accord ance with table 1 .

Table 2 Active ingredient and carrier mixtures used in decay tests

Example Active ingredient and its Carrier and its concen- concentration tration

Commercial active ingre

dient:

1 5% of Tebuconazole 30% of MHEA

2 5% of Tebuconazole 30% of MHEA/PHEA

New active ingredient:

3 5% of benzoic acid 30% of MHEA

4 5% of benzoic acid 30% of MHEA/PHEA

5 5% of EDTA in acid form 30% of MHEA

6 5% of EDTA in acid form 30% of MHEA/PHEA

7 5% of CEBE 2 30% of MHEA

8 5% of CEOS 30% of MHEA

9 5% of BHTEB 30% of MHEA

10 5% of BEPRE 30% of MHEA

1 1 5% of SBBW-30 100% of White Spirit

Comparisons:

Untreated wood

12 (ref.)

Wood treated with carrier

alone

13 (ref.) 30% of MHEA

14 30% of MHEA/PREA

15 (ref.) 100% of White Spirit

EDTA ethylenediaminetetraacetic acid

CEBE2 43% of MHEA + 43% of cetyl pyridinium benzoate + 9% Pre- ventol MP100 + 5% EDTA

CEOS 13% of stearic acid + 33% of lactic acid-oligomer + 6% of cetyl pyridium chloride + 48% of MHEA

BHTEB 5% of Preventol A8 + 5% of benzoic acid + 90% of MHEA BEPRE 100 4% of Preventol MP100 +92% of MHEA SBBW-30 30% (25% of stearic acid + 12% benzoic acid + 65% of alkylbenzyldimethylammonium chlorides of various alkyl chain lengths) + 70 % White Spirit

Preventol A8 Tebuconazole

Preventol MP 100 IBPC = 3-iodine-2-propynyl butyl carbonate

Table 3 Active ingredient mixtures used in mildew and blue stain tests

Example Active ingredient and its Carrier and its concen- concentration tration

Commercial active ingredi

ent

16 5% of IBPC 30% of MHEA

17 5% of IBPC 30% of MHEA/PREA

New active ingredient

18 5% of benzoic acid 30% of MHEA

19 5% of benzoic acid 30% of MHEA/PREA

20 5% of EDTA in acid form 30% of MHEA

21 5% of EDTA in acid form 30% of MHEA/PREA

22 5% of SBB 30% of MHEA

23 5% of CEBE2 30% of MHEA

24 5% of CEOS 30% of MHEA

25 5% of BHTEB 30% of MHEA

26 5% of BEPRE 100 30% of MHEA

27 5% of SBBW-30 100% of White Spirit

Comparisons:

Untreated wood

28 (ref.)

Wood treated with

carrier alone

29 (ref.) 30% of MHEA

30 30% of MHEA/PREA

31 (ref.) 100% of White Spirit

IBPC = 3-iodine-2-propynylbutylcarbonate

2.3 Extraction tests of the wood material

Oven-dry pine surface samples (15 x 15 x 5 mm) were extracted under five different extraction schedules (schedules 1-5). Unprocessed (unextracted) wood samples were used as reference material for the extracted wood material.

Extraction schedule 1 , Water extraction

The wood samples were impregnated (vacuum impregnated) with water before ex traction. The water-impregnated samples were extracted in an autoclave for 20 minutes at a temperature of 121 °C. Extraction schedule 2, MHEA1

Wood samples were impregnated (vacuum impregnation) with a 50% MHEA carrier and the impregnated samples were extracted in an autoclave for 20 minutes at a temperature of 121 °C. Then the samples were rinsed with cold water until the rinsing water was limpid (at least 3^f rinses, one water rinse = in water over night under press).

Extraction schedule 3, MHEA2

Wood samples were impregnated (vacuum impregnation) with a 50% MHEA carrier and the impregnated samples were extracted in an autoclave for 20 minutes at a temperature of 121 °C. Then the samples were rinsed with cold water under press over night (one rinse).

Extraction schedule 4, Solvent extraction

Wood samples were extracted with acetone in a Soxhlet apparatus for 4 hours. After this the samples were further extracted with distilled water in a Soxhlet apparatus for 4 hours. The samples were not dried between the extractions.

Extraction schedule 5, Solvent-MHEA-extraction

Wood samples were extracted with acetone in a Soxhlet apparatus for 4 hours. Then the samples were further extracted with distilled water in a Soxhlet apparatus for 4 hours. The samples were not dried between the extractions. After the water extrac- tion, the samples were air dried and impregnated (vacuum impregnation) with a 50% MHEA carrier. After they had been impregnated, the samples were rinsed with water under press over night.

2.4. Biological effectiveness of mixtures of active ingredient and ancat and extracted wood 2.4.1 Decay tests

Small pine surface samples (15 mm x 15 mm x 5 mm) were vacuum impregnated with the active ingredient carrier mixture under study (table 2). Untreated samples and samples treated merely with ancat carriers or a White Spirit solvent were used as a reference. The brown-rot fungus Coniophoraputeana, BAM Ebw was selected as the test fungus. The fungus strain is derived from the strain collections of VTT Technical Research Centre of Finland, Building, Built Environment. The amounts of mixtures of active ingredient-carrier absorbed into the samples (re tention kg/m ³ ) were determined by calculatory means and dry basis weighing (dry weights of the samples before and after impregnation and rinsing). Part of the sam ples was rinsed with water before the decay tests were started. The rinsing was performed by impregnating the pieces with water and rinsing the samples under water for 4 days. The rinse water was renewed four times during the rinsing opera tion. The rinsing was performed under modified EN 84 standard. The amounts of active ingredient-carrier absorbed into the samples were determined also after the rinse.

The decay tests were conducted under accelerated and modified EN 1 13 standard. The reference samples and both unrinsed and rinsed test samples were allowed to decay over a period of 5 weeks. The effectiveness of the impregnation treatments was determined on the basis of the weight loss caused by the fungus.

2.4.2 Mildew and blue stain tests

In mildew and blue stain tests, pine surface wood samples (25 x 50 x 5 mm) were vacuum impregnated with mixtures of active ingredient and carrier (table 3). The samples were not rinsed.

The anti-mildew and anti-blue stain effect of the mixtures of active ingredient and carrier and their references were examined in a laboratory by a suspending method. The test samples and the reference samples were suspended in random order in exposure chambers. The relative humidity in the chambers was regulated by means of water in the range 95-100% at a test temperature of 20 °C {+1-2 °C).

Blue stain and mildew fungus suspensions were injected into the test boxes before the test was started. The mildew suspension contained three mildew species that thrive in wood: Aspergillus versicolor (E1), Gladosporium sphaerospermum (R7) and Penicillium sp. (1 017). The blue stain suspension consisted of the following species: Aureobasidium pullulans (T1), Sclerophoma entoxylina (Z17) and Cerato- cystispilifera (Z1 1 ). The fungus strains are derived from the strain collections of VTT Technical Research Centre of Finland, Building, Built Environment. The moulding of the test samples was monitored visually at the end of 2, 4, 6, 8 and 10 weeks from the start of the test on a scale 0-5.

0 no growth

s1 = marks of starting growth (microscopically observable) 2 1 -10% of the area covered by microbial growth (microscopically ob servable)

3 10-30% of the area covered by microbial growth (visually observable)

4 30-70% of the area covered by microbial growth (visually observable)

100% of the area covered by microbial growth (visually observable)

3. Results

3.1 Anti-decay effect of the mixtures of active ingredient and carrier and the extrac tion schedules

The cellar fungus (C. puteana) is a brown-rot fungus that causes weight loss and reduces the strength of wood material. The metabolism of brown-rot fungi utilises the hydrocarbon structural components of wood (hemi-cellulose and cellulose) and also modifies the lignin structure. If brown rot proceeds over a long period, there will remain only brittle lignin, which decomposes into dust even under light stress.

The results of the decay tests are illustrated in tables. The results indicate that all of the mixtures of active ingredient and carrier and ancat carriers under study, when not rinsed, prevented alone the decay caused by C. puteana in an accelerated de cay test. In all the cases, the weight loss of the samples was smaller than the weight loss set as the preservative effect limit under the EN 1 13 standard (<3 %).

A weight loss of less than 3% was achieved in the rinsed samples when the pre servative contained tebuconazole-MHEA, tebuconazole-MHEA+PREA, CEBE2- MHEA, CEOS-MHEA or BHTEB-MHEA. A weight loss limit of almost 3% was achieved with rinsed samples containing benzoic acid-MHEA+PREA (4.2 % by weight weight loss) or EDTA-MHEA+PREA in acid form (5.2% weight loss). The rinse clearly reduced the anti-decay effect of benzoic acid-MHEA (7.3% by weight loss) and of EDTA-MHEA in acid form (12.7% weight loss).

When unrinsed, both the ancat carriers prevented efficiently the weight loss caused by rot fungus in the test samples. The effectiveness of MHEA+PREA decreased after rinsing, and a weight loss of 9% was stated in the test samples. WhiteSpirit did not prevent the weight loss caused by rot fungus. By contrast, a mixture of SBBW30 and WhiteSpirit proved to have a high anti-decay effect both when rinsed and not rinsed. The objective of the extraction tests was to determine whether removal of e.g. sol uble sugars or structural components soluble in the carrier increases the decay re sistance of wood. Ancat carriers have proved (cf. the results of the extraction tests) to extract hydrocarbons and particularly xylane of hemi-cellulose from the wood ma- terial. The results of the decay tests indicated that water extraction (extraction schedule 1 ), MHEA1 (extraction schedule 2) and solvent extraction (extraction schedule 4) did not increase the decay resistance of extracted wood material (weight losses >30%). By contrast, in samples treated under extraction schedules 3 (MHEA2) and 5 (solvent-MHEA extraction) the weight loss caused by rot fungus was under the 3% limit prescribed by the standard.

Figure 3. Effect of the extraction schedules on the anti-decay properties of wood material.

Table 4 presents the active ingredient-carrier contents absorbed into the samples during impregnation. The contents were relatively high, with variations in the range 190-240 kg/m ³ . Rinsing had no notable effect on the absorption.

Table 4. Active ingredient contents in the test samples after impregnation and rins ing.

Example Mixture active ingredient-carrier Retention kg/m ³

Not rinsed Rinsed

13 MHEA 201 194

14 MHEA+PREA 182 182

3 Benzoic acid-MHEA 213 225

4 Benzoic acid-MHEA/PREA 204 214

5 EDTA-MHEA in acid form 222 217

6 EDTA-MHEA/PREA in acid

form 209 203

1 Tebuconazole-MHEA 222 222

2 Tebuconazole-MHEA/PREA 194 193

7 CEBE2-MHEA 205 208

8 CEOS-MHEA 231 233

9 BHTEB-MHEA 235 235

10 BEPRE100-MHEA 236 228 3.2 Anti-mildew and anti-blue stain effect of mixtures of active ingredient/carrier and extraction schedules

Blue stain fungi penetrate into the wood material structure, and by staining the wood, they entail discolouration and alter the moisture behaviour of the material (the ma terial will have higher water absorption). The metabolism of blue stain fungi utilises mainly soluble nutrients, and they do not usually produce weight losses or decrease the strength of the wood. By contrast, mildew fungi grow only on the surface of the wood material. Mildews do not penetrate into the material structure and thus do not cause weight losses or decreased strength. Mildews live on the soluble nutrient pre sent on the material surface. The damages caused by mildews relate to discolour ation and malodour and possible health hazards.

The blue stain tests did not yield any results. Blue stain was not observed in one single treated or untreated sample during an exposure period of 10 weeks. In the case of the untreated reference, this zero result may also be partly due to excessive moisture of the samples, which in turn is caused by the hygroscopicity of the mix tures of active ingredient and carrier, to the susceptibility of blue stain fungi to the compounds under study and/or to transfer of the active ingredients also to the un treated reference sample, owing to the high transfer potential of the carrier.

The results of the mildew tests are shown in tables. The corresponding examples are given in table 3. Mildew growth was prevented completely in an exposure test of 10 weeks when the samples were treated with the following mixtures of active ingredient and carrier: benzoic acid-MHEA- (example 18), benzoic acid- MHEA+PREA (example 19), EDTA-MHEA in acid form (example 20), EDTA-MHEA- PREA in acid form (example 21 ), SBB-MHEA (example 22), CEBE2-MHEA (exam ple 23) and BEPRE100-MHEA (example 26) and SBBW30-WhiteSpirit. In untreated control samples and test samples treated with WhiteSpirit, moulding reached the mildew index 5 (100% of the sample surface was covered by mildew growth) after 6 weeks' exposure. Moderate mildew growth was observed in the two samples treated with ancat carriers. The mildew index reached the value 2 during the expo sure (mildew growth not yet visible). Moderate mildew growth (mildew index 2) was also observed in test samples treated with active ingredient mixtures of CEBE2- MHEA (example 23) and CEOS-MHEA (example 24). The objective of the extraction tests was to determine whether the removal of e.g. soluble sugars or structural components soluble in the carrier increases the mildew resistance of the wood. The results of the mildew tests show that water extraction (extraction schedule 1 ), MHEA2 (extraction schedule 3) and solvent extraction (ex traction schedule 4) did not increase the mildew resistance of the extracted wood material, with a mildew index variation between 3 and 5 in these cases (visible and abundant growth). On the contrary, moulding was moderate in samples treated un der extraction schedules 2 and 5 (MHEAI and solvent-MHEA extraction) (mildew index 1 or less).

4. Conclusions of mibrobicide studies

The mixtures of active ingredient and carrier were observed to have a distinct pre ventive potential both with respect to decay and to mildew formation. The decay tests determined the anti-decay effect of MH/EA and MH/EA+PR/EA carriers and of active ingredients mixed in these (benzoic acid, EDTA in acid form, tebuconazole, CEBE2, BHTEB, BEPRE 100-MHEA, CEOS). The decay tests also determined the effect of SBB dissolved in a WhiteSpirit solvent. Wood samples extracted under five different extraction schedules were also included in the decay tests.

The mixtures of active ingredient and carrier efficiently prevented decay caused by C. puteana in an accelerated decay test. The test results indicated that the mixtures of active ingredient and carrier efficiently prevented weight loss caused by rot fungus in the treated wood samples also after rinsing. The most efficient active ingredient mixtures with the highest anti-decay potential occurred among the formulations pro duced by the company Granula Oy.

The mildew and blue stain tests, in turn, determined the anti-mildew effect and anti blue stain effect of MH/EA and MH/EA+PR/EA carriers and of active ingredients mixed in these carriers (benzoic acid, EDTA, IBPC, SBB, CEBE2, CEOS, BHTEB, BEPRE 100-MHEA in acid form) and SBB dissolved in a WhiteSpirit solvent. The test results showed that the mixtures of active ingredient and carrier actively pre vented mildew growth on the surface of the treated wood samples during an expo sure period of 10 weeks. No blue staining was observed. This result may be due to excessive moisture of the samples, which in turn was caused by the hydroscopicity of the mixtures of active ingredient and carrier, to the susceptibility of blue stain fungi to the compounds under study and/or to transfer of active ingredients also to the untreated reference sample, owing to the high transfer potential of the carrier. The effect of extraction of the soluble and structural components of wood material on decay and mildew formation was determined by treating the wood material under five different extraction schedules. Water and solvent extractions had no effect on the decay and mildew resistance of the wood material. Decay caused by C. puteana was inhibited in the cases where the wood material contained a carrier after the extraction.