DK144695B - PROCEDURE FOR THE CONSERVATION OF CELLULOS MATERIALS IN THE FORM OF TREES OR A FIXED TREE PRODUCT - Google Patents

Description

(19) DENMARK iff) f Λ ^ -lj \

S (12) PUBLICATION MANUAL od 144695 B

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Application No. 1275/74 (51) int.CI.3 B 27 K 3/34 (22) Filing date 8 Mar. 1974 (24) Race day 8 Mar 1974 (41) Aim. available Sep 10 1974 (44) Submitted May 17, 1982 (86) International Application no.

(86) International filing day (85) Continuation day - (62) Master application no. -

(30) Priority Mar 9 1975, 114i 9/75, GB 15 · Jun. 1975, 28544/75, GB

(71) Applicant ALBRIGHT & WILSON LIMITED, Oldbury, GB.

(72) Inventor John Leslie Bennett, GB: Glyn Miller, GB: Barry Ar thur Richardson, GB.

(74) Associate Engineering Company Budde, Schou & Co.

(54) Process for preserving cellulose material in the form of wood or a solid wood product.

The present invention relates to a process for preserving cellulosic material in the form of wood or a solid wood product not substantially infected with wood-destroying fungi, wherein the cellulosic material is treated with an organotin compound having three alkyl, cyclohexyl and / or phenyl groups adjacent to it. to a tin atom through Sn-C bonds. These Q-derived solid products are e.g. plywood, chipboard and wood fiberboard.

The use of trialkyltin compounds, especially tributyltin oxide, as a wood preservative has been increasing in recent years, but f has been possible only in organic solvent, which has t - severely limited their utility, namely in the area of preservation of finished timber and carpenter products and certain repam 3 2 U4895 rations (ie, treatment of wood or solid wood products after infection with and partial destruction by infestation by wood-destroying fungi), where organic solvents are usually used to prevent the wood from swelling during treatment and thereby in folding, as is otherwise the case with aqueous systems, which is disastrous for finished timber structures as well as for carpentry items such as furniture and building components, such as windows and doors.

Consequently, systems based on organic solvents are only suitable for repairing shaped wooden structures, ie. after these are infected, e.g. in the form of beams in old houses, or for use in the preservation treatment of expensive furniture such as furniture, whereas organic systems are less suitable for factory use due to the associated health hazards, fire hazards and solvent loss.

As a result, trialkyltin compounds, especially TBTO systems in factories, have not been used in the past because they are water insoluble. This is an undesirable situation because, in fact, orga-notin fungicides are better as fungicides in terms of environmental protection than their main competitor, copper-berchromarsenite cysts, which contain three toxic elements. In addition, the organotin compounds are colorless, whereas the copper salts and the copper chromium salts are green and teal.

Norwegian Patent No. 119,555 and the corresponding French Patent No. 1,526,905 disclose, as is well known in the art, an antifungal composition comprising, inter alia, a triorganotin compound of formula +

R2 J-SnR3 X

(ch2ch20) xh wherein R is alkyl, x is about 10 and X are halide. The organotin compounds are reportedly highly water soluble and in their salt form they appear to be better retained than electrically neutral compounds for processed substrates based on wood materials. For this reason, they are especially used for impregnating food packaging, especially paper, as they inhibit mold growth. These patents themselves relate to some even more complex organotin compounds, cf. the formula: 3 144695 (CH ~ CHo0) H CHoCHo0) Η j 2 2 'x i 2 2' p [~ R'-N-CH2CH2CH2N-Sn (C3H7) 3'j ++ 2X ~,

Sn (C3H2) 3 (CH2CH2O) gH

wherein R 1 is alkyl of 12-18 carbon atoms and x + p + q is approx. 10th

Such compounds are expensive as they have to be custom made and it is expensive with such a complex structure.

The aqueous solutions of these complexes are used to impregnate absorbent material to be communicated with fungicidal properties, usually wood, but also extensive cardboard, paper, textiles, etc. The solutions are effective when used with all types of wood, wet or dry, but is of particular use in treating soft woods as pine for the design of threaded boxes for wrapping agricultural and other food. Due to the need for elasticity of soft wood piles in such threaded boxes, the piles usually have a high water content and are very susceptible to mold attacks, causing an unwanted discoloration of the wood. The compounds have only been tested against mold attacks on wood.

It has now been found that an aqueous organotin-containing system, similar to those previously used in wall purification or as biocide in a cooling water system, has a surprisingly good activity as a wood preservative, ie. for pre-treatment of wood before it is infected with wood-destroying fungi.

It has even been found hereby that in the composition applied to the tree the total amount of organotin compound required to induce a given degree of preservation, ie. impregnation with a given amount of organotin in the wood, substantially less than that required when the organotin compound is applied in the form of a traditional mineral turpentine impregnation.

German Patent Specification No. 2,132,701 discloses an aqueous solution of thiourea and a quaternary ammonium compound (which is the same as in the preferred compositions used according to the invention) for application to freshly cut wood, but to mark to stop its discoloration due to the influence of the fungi classified under the group "blister" - 4 144895 fungi. Such fungi mostly attack the ends of the timber, and this attack is essentially a surface effect. In fact, the biological group in which the blister sponges fall is very different from the group in which the woodworms which the process of the applicant's invention aims to treat fall. The blister sponges are undesirable due to discolouration, but are not considered to be really destructive, as is the case with the "woodwire" sponge group. However, it is quite clear that neither the German nor the Norwegian writings are mushrooms which fall under the far more serious type of attack "wooden thread", which the present invention specifically aims to combat.

The quaternary compounds in question are thus probably fungicidal, but are not described as particularly active against rot fungus.

Against this background, it must therefore be considered surprising that the addition of a quaternary compound, which has not previously been described as effective against wood yarrow, should, in combination with an organotin compound, make it possible to reduce the use of the much more expensive organotin component to a 4 or 5 times as low, while still preserving comparable efficiency.

The complex water-soluble quaternary ammonium organotin compounds known from the Norwegian patent may be used in aqueous solution for the treatment of wood, but these compounds are expensive as they have to be specially prepared for this purpose. In contrast, the trialkyl, phenyl and / or cyclohexyltin compounds used in the process of the invention and in particular TBTO are commonly used biocides, e.g. for wood treatment in organic solution, and the specified quaternary compounds are also well known as surfactants, some of which have bactericidal activity. Thus, the method of the invention is far cheaper to practice.

Thus, the present invention provides a method for preserving a cellulose material in the form of wood or a solid wood product which is characterized in that the treatment of cellulose material is carried out with an aqueous system containing 0.01-0.4% by weight of the triorganotin compound and 0.02 - 5% by weight of a monoquaternary ammonium compound in a sufficient amount to disperse the triorganotin compound under the treatment conditions, providing an uptake of 0.15-1.5 kg of triorganotin compound per m wood or wood product.

As used herein, the term "impregnation" is used for cellulosic material in its conventional sense, namely, the uptake of preservative (here the triorganotin compound) per day. volume unit of material, determined from its mass / volume trapped of preservative fluid of known concentration absorbed by a known volume of cellulose material.

Examples of suitable triorganotin compounds for the purposes of the invention are those of the formulas

R R R

1 i i

R-Sn-X or R-Sn-Y-Sn-R

I I i

R R R

wherein each R may be the same or different and represents an alkyl group of 1-10 and preferably of 2-6 carbon atoms, especially n-butyl or hexyl, a cyclohexyl group, and hydroxyalkyl group, preferably of 2-6 carbon atoms such as a hydroxyethyl -group or a phenyl group, X is an electronegative atom or an electronegative group such as a group having a Hammett value greater than +0.2 when present as an ortho substituent in benzoic acid and Y is oxygen or sulfur. These non-carbon-to-tin substituents (acid residues) are of minor importance for the biocidal action of the triorganotin compounds, cf. "Progress of chemical research", Volume 16, page 377, Table 3 (1970).

Atoms and groups represented by X include halogen atoms such as fluorine, chlorine, bromine and iodine, pseudohalogen groups such as cyanide, cyanate and thiocyanate groups, inorganic anions such as nitrate, sulfate, phosphate, thiophosphate and boron ions, carboxylate groups such as formate, acetate, propionate, acrylate, methacrylate and longer chain carboxylate groups such as groups derived from alkanoic acids having 3 to 10 carbon atoms, e.g. hexanoate. Preferably X is an inorganic atom or an inorganic group, i.e. a halogen or pseudohalogen or an inorganic anion such as those described above. Specific triorganotin compounds of good utility include the following: 6 U4S95

Bis- (tri n-butyltin) oxide bis- (tri n-butyltin) sulphide tri-n - butyltin acetate tri-n - butyltin acrylate tri-n - butyltin methacrylate tri-n - butyltin phosphate tri-n-butyltin chloride

The corresponding trihexyltin, tricyclohexyltin and triphenyltin compounds are also particularly useful. According to the invention, it is preferred that the triorganotin compound be tri-n-butyltin oxide. This connection is easily accessible, efficient and inexpensive as well as reliable in use.

Quaternary ammonium compounds which may be used generally fall within one of the following classes: 1) compounds of the general formula R "+ I 2 R'-N - R" "R" "wherein each of the substituents R ', R", R "1 and R" which are the same or different are a branched or unbranched, saturated or unsaturated alkyl group having 1 to 20 carbon atoms, aralkyl group having 7 to 19 carbon atoms, e.g. tolyl, aralkyl group having 7 to 27 carbon atoms, e.g. benzyl or alkylbenzyl, or aryl group having 6 to 20 carbon atoms, e.g. an aromatic hydrocarbyl group such as a phenyl group, or their corresponding alkylene oxide condensates, two of which may together form a saturated or unsaturated heterocyclic ring having 5, 6 or 7 ring atoms and with the quaternary nitrogen atom as the only ring heteroatom, e.g. such as in pyridine, or with at least one additional heteroatom in the ring, e.g. an oxygen atom to form a morpholine or oxazole ring, and Z is a water-solubilizing anion, e.g. a halide ion such as a chloride, or bromide or sulfate ion.

Preferably, R 'is a benzyl group, a core alkyl benzyl group having at least one alkyl group having e.g. 1 to 20 and usually 8 to 15 and preferably approx. 12 carbon atoms in the alkyl group, or a 7 U 695 alkyl group having 8 to 20 and especially 12 to 16 carbon atoms, R "and R" are alkyl groups having 1 to 6 carbon atoms, especially methyl groups, and R "" is a phenyloxyalkylene group. or phenylpoly (oxyalkyl) group having 1 to 6 and usually 1 to 2 oxyalkylene groups, or an alkyl group having 1 to 20 and preferably 8 to 18 carbon atoms, especially having about 12 carbon atoms. Alkylene groups in the above R "" usually have 2 to 4 carbon atoms and are usually ethylene or propylene groups. These quaternary ammonium compounds are easy to obtain and provide stable dispersions or emulsions, and for this reason, it is particularly preferred that the monoquaternary ammonium compound include methyl groups and either a benzyl group and an alkyl group having 8-18 carbon atoms or an alkyl benzyl group. with one alkyl group bonded to the nucleus having 8-18 carbon atoms and another methyl group.

Particularly useful quaternary ammonium compounds include benzalkonium chlorides of formula CH0 + I 3 C6 H5 CH2 - N - E Cr _ CH3 wherein R is a mixture of alkyl groups of 8-18 carbon atoms, but predominantly C C ·, benzethonium chloride of formula CH, CH- + < CtI3> 3 C "2 C - O - / - -0 <CH2) 20 (CH2) 2 N Cl CH3 ^^ CH3 and methylbenzethonium chloride: hexadecylpyridinium chloride - _" I + / \ - (-CH2), - CH- Cl 2/2 15 3 8 1A A 6 9 5 and hexadecylpyridinium bromide, hexadecyltrimethylammonium bromide r CHq Ί + I 3 C16H33 j C2H4 j ci2H25 Br CIi3

Di-n-octyl1-dimethylammonium bromide 9H3 + + C8H17 "j - C8H17 Br" iH3 and n-dodecylbenzyltrimethylammonium chloride n ~ C12H25 \ _ CH3 \ -CH0 - N - CHq Cl

[w ^ -J

Means for use in the method of the invention are conveniently stored and transported in the form of a concentrate.

Such concentrates usually contain from 1 to 20% by weight and preferably from 5 to 15% by weight of the triorganotin compound and from 20 to 90% by weight and preferably from 35 to 50% by weight of the quaternary compound, the remainder of the concentrate being mainly water. It is advantageous according to the invention that the quaternary compound and the triorganotin compound be present in a weight ratio of 2: 1 to 6: 1 and preferably of about 2%. 4: 1. This ensures optimum stability, both in the form of concentrate and when applied. When the concentrate is to be used, it is diluted with sufficient water to produce an aqueous system of the required concentration (i.e., from 0.01 to 0.40 and preferably 0.25% by weight of triorganotin compound). This dilution is usually done by adding 1 part of concentrate to 10 to 100 and preferably 50 to 500 parts of water, which depends on the percentage of tin in the original concentrate, and e.g. For example, a concentrate containing 10% triorganotin compound can be diluted 40 to 1000 times and will preferably be diluted 100 times. Preservatives used in the process of the present invention can be applied either to wood or similar products alone or together with other preservatives, e.g. conventional poisons. The preferred quaternary ammonium salts are inherently biological, e.g. insecticide, activity. Additional materials that can be used in the impregnation are conventionally used in aqueous compositions. Such additional materials include e.g. water-soluble salts of chlorinated phenols such as sodium pentachlorophenate. They may also include insecticidal materials. In addition, if desired, the preservatives can be used with mixtures of other preservative compositions such as inorganic chromates or dichromates. The preservative compounds will be applied to the wood or similar products in varying amounts within the range indicated above, depending on the nature of the substrate or substrate and its intended use. It has been found that such treatment, which provides an impregnation of 0.15-3-0.5 kg (per m tree or derived product) triorganotin compound, provides appropriate protection against the common wood-destroying Basidomyeets fungi. An impregnation of 0.25 kg / m is generally satisfactory for preserving wood and wood products for normal construction purposes.

The application of the impregnating agent by the method according to the invention to wood or solid wood products can be carried out in several different ways. The impregnating agent may be applied by aspiration into the timber to be preserved, soaking the timber in a solution containing the preservative for such a period until sufficient absorption is obtained. However, the preservative is preferably applied by vacuum and / or pressure-impregnation technique prepared to ensure that the preservative is completely absorbed in wood. Thus, the cellulose material can be brought into contact with the aqueous system, the pressure raised to above atmospheric pressure, the material still in contact with the system, and the pressure again changed to atmospheric pressure, the pressures and time periods in which the pressure is maintained are sufficient to produce for impregnating with the desired amount of preservative. Generally, the wood material is subjected to a lower pressure than atmospheric pressure before being brought into contact with the aqueous system. Eg. For example, wood can be placed in a chamber, the pressure in the chamber is reduced, the preservative, which is usually at room temperature, is added so as to cover the tree, the pressure is raised to above atmospheric pressure, where it is maintained for a certain period thereafter, it is reduced to atmospheric pressure, optionally followed by a short stay at reduced pressure. Alternatively, the pressure decrease may initially be omitted. These various forms of technique with and without pressure lowering initially are known as full-cell and empty-cell techniques and are incompletely described in "The Preservation of Timber" by W.P.K. Findley, Publ.

Black 1962 pages 36-41 and in "Wood Preservation" by G.M. Hunt and G.A. Garratt, 3rd edition American Forestry Series, McGraw-Hill, 1967, for wood-waterproofing with actual solutions; salts dissolved in water or, on the other hand, TBTO dissolved in organic solvent. However, using both dispersion and emulsion impregnation systems, there is the danger that they will be broken by contact with the wood under high pressure. Therefore, it is surprising when it has now been found that the dispersion or emulsion impregnation systems used according to the invention are stable enough to withstand pressure or pressure / vacuum impregnation methods, cf. claims 5 and 6.

The concentration of triorganotin compound in the aqueous system, the size of the pressures, the maintenance time of the period at super- and subatmospheric pressures, and the nature of the cellulose material affect the absorption of the impregnating agent by the material. Thus, increasing the concentration or superatmospheric pressure, residence time at superatmospheric or subatmospheric pressure, or decreasing the subatmospheric pressure leads to an increase in the absorption of impregnating agent by the wood material. Changing the material towards greater absorbency leads to an increase in the absorbed amount of impregnant, which is also the case when treating a cellulose material with a smaller cross-sectional area. Generally, vacuum pressure times of 5 minutes to 2 hours and usually from 10 to 30 minutes are used, with the vacuum being kept below 100 mm Hg. Superatmospheric pressures of 2-20 kg / cm, e.g. 8-15 kg / cm at residence times of 5 hours to 20 minutes, e.g. from 2 hours to 30 minutes, are appropriate as the longer residence times or application times are used when the lowest pressures are used.

n 1U695

These conditions are generally suitable for use with aqueous systems containing 0.05-0.25% triorganotin compound.

The aqueous systems used in the method according to the invention are very useful in preserving wood (or derived solid products) against infestations of wood-destroying Basido mycotic fungi such as Coniophora cerebella, Polystictus versicolor, Lenzites trabea and especially Poria monticola, among which the latter is resistant to the conventional copper chromar arsenate preservatives.

The invention is further illustrated in the following Examples, in which Examples 1 and 2 describe the preparation of suitable concentrates, while Examples 3-6 illustrate the practice of the process of the invention.

Example 1

An aqueous composition containing 10% bis (tri-n-butyltin) oxide and 40% alkylbenzyl dimethylammonium chloride is prepared by mixing 1 part bis (tri-n-butyltin) oxide with 8 parts "Benzalkonium chloride" ® B.P. (a commercial aqueous composition containing 50% by weight of alkylbenzyl dimethylammonium chloride in which the alkyl groups contain 8-18 carbon atoms) and addition of 1 part of water. All concentrations and proportions stated are by weight.

Example 2

An aqueous composition containing 10% bis (tri-n-butyltin) oxide and 40% (n-higher alkylbenzyl) trimethylammonium chloride is prepared by mixing 1 part bis (tri-n-butyltin) oxide with 8 parts of "Gloquat C" (a commercial aqueous composition containing 50% (n-higher alkylbenzyl) trimethylammonium chloride) and 1 part of water are added. All concentrations and proportions are by weight.

The n-higher alkyl group present in the benzyl group as a substituent is believed to be an n-dodecyl group.

Example 3

The wood preservative activity of bis- (tri-n-butyltin) oxide (hereinafter referred to hereinafter as TBTO) in the preparations derived from the concentrates described above in Examples 1 and 2 is compared using a mycological sample. with the activity of the same compound in a preparation made from a light petroleum solvent. In this test, blocks of splinter wood derived from Scottish common forest pine, Pinus sylvestris, measuring 15 mm in length and 10 x 7 mm in cross-section, are treated by vacuum impregnation with dilutions of the three compositions to obtain varying uptake of bis - (tri-n-butyltin) oxide. After drying, half of the blocks treated with the aqueous preparations are washed out by vacuum impregnation with deionized water followed by soaking in deionized water for 5 days, changing the water daily. The leached blocks are then dried and all the blocks are exposed to fungal infestation by brown rot fungi of the Basidiomycet species Coniophora cerebella by placing the blocks on active soil and food block cultures for 6 weeks. The weight loss due to fungal attack is listed in the following table: bis- (tri-n-butyltin) oxide in light petroleum as solvent Concentration of TBTO in upl. Uptake of TBTO in wood% weight loss on

ISLAND

% (weight / weight) not leached kg / m due to advice 0.25 1.15 0 0.16 0.74 1.1 0.10 0.45 6.5 0.063 0.27 18.6 0.040 0.18 15.8 bis (tri-n-butyltin) oxide and benzylalkyldimethylammonium chloride aqueous composition of Example 1.

Concentration of TBTO in training Absorption of TBTO in wood% weight loss of% (w / w) ___ kg / m3_ due to advice not washed out 0.063. 0.44 0.40 0.28 0. 0.025 0.18 6.0 0.016 0.11 2.5 0.010. 0.07 12.5 washed out 0.063 0.43 0 0.040 0.28 4.0 0.025 0.18 3.7 0.016 0.11 28.3 0.010 0.07 19.6 13 U4695 bis- (tri-n-butyltin ) oxide and alkylbenzyltrimethylammonium chloride aqueous composition of Example 2.

Concentration of TBTO in upline Uptake of TBTO in wood S weight loss of% (w / w) _kg / m3_ due to advice not washed out 0.063 0.46 0 0.040 0.27 0 0.025 0.17 10.0 0.016 0.11 17 8 0.010 0.07 18.4 bis- (tri-n-butyltin) oxide and alkylbenzyltrimethylammonium chloride aqueous composition of Example 2

Concentration of TBTO in training Absorption of TBTO in wood% weight loss on% (w / w) ----2Δ ”- due to advice washed out 0.063 0.43 0 0.040 0.27 0 0.025 0.17 0.5 0.016 0, 11 15.0 0.010 0.07 29.1 Untreated 0 0 47.6

These results indicate the following interval for impregnation with or uptake of bis- (tri-n-butyltin) oxide, ie. exciting about the retained amounts of impregnating agent, where the weight loss first becomes insignificant:

ISLAND

In petroleum as solvent not leached 0.74-1.15 kg / m

ISLAND

Aqueous quaternary ammonium preparation not washed out 0.18-0.28 kg / m :: according to Example 1 washed out 0.28-0.43 kg / m3

ISLAND

Aqueous quaternary ammonium preparation not washed out 0.17-0.27 kg / m :: according to Example 2 washed out 0.17-0.27 kg / m3

These results indicate that the activity of bis (tri-n-butyltin) oxide applied in aqueous quaternary ammonium containing preparations, e.g. the impregnation solution concentrates prepared according to Example 2 are approx. 5 times greater than when the compound is applied in the conventional manner in light petroleum as a solvent.

14 144695

Example 4 Lumber is treated with the compositions described in Examples 1 and 2 using a conventional Bethell full cell method.

After the timber is closed inside a sealed cylinder, vacuum is initially applied to this container. The cylinder is then supplied with preservative liquid for rinsing the wood therein while maintaining the applied vacuum and when the rinsing is complete, the vacuum is released and pressure is applied. Finally, the pressure is released, the preservative is pumped out, and finally vacuum is applied before the cylinder is allowed to return to atmospheric pressure and the timber is removed. The preservative is diluted with water to obtain a concentration which depends on the final absorption or retention of the impregnating agent desired. In addition, the impregnation pressure and residence times varying this pressure and the initial vacuum are applied to match the species and cross-section of the timber being treated. Thus, e.g. an initial vacuum residence time of 20 minutes, suitable for normal construction or frame timber used in the raw house in buildings. If a pressure of 10 kg / cm is applied 2 for 90 minutes or a pressure of approx. 12.5 kg / cm is applied for 60 minutes, 3 a net absorption of more than 200 kg of diluted preparation is obtained. m in split wood of ordinary Scottish forest fir. It takes longer to treat more resilient species such as Douglas fir,

Tsuga and spruce. For example, pressure of 10 kg / cm for 120 minutes 2 or 12.5 kg / cm for 90 minutes. If the compositions of Examples 1 and 2 are diluted to 1.25% of the initial concentration with water, i. to a content of 0.125% bis (tri-n-butyltin) oxide, this gives 3 net absorption of 200 kg of diluted preparation per ml. m a net retention or absorption of preservative of at least 2.5 kg of concentrated preparation per day; m (which is equivalent to 0.25 kg (tri-n-butyltin) oxide per m tree) throughout the split tree. This is an appropriate or sufficient preservation for preservation for use in normal buildings.

15 1U695

Example 5 Timber is treated with the compositions described in Examples 1 and 2 using a conventional Lowry cell method. The process is the same as the Bethell full-cell method described in Example 4, except that one fails to apply vacuum initially and the net absorption is reduced by approx. 40%. Thus, the pressures and residence times described in Example 4 give net absorptions by the Lowry process of over 120 kg of diluted preparation 3 per ml. m, and if the compositions described in Examples 1 and 2 are diluted to 2.1% of the original strength of the composition with water, i. to a content of 0.21% bis (tri-n-butyltin) oxide, this net absorption provides a net retention of preservative of at least 2.5 kg 3 concentrated preparation per m, which is equivalent to 0.25 kg of 3 bis- (tri-n-butyltin) oxide per ml. m throughout the tree's splint, in the case of ordinary Scotch forest pine, Pinus sylvestris, This is the same retention as obtained by Bethell's full-cell method as described in Example 4; but the 40% reduction in net absorption leads to a lumber which is substantially drier after treatment.

Example 6

The aqueous composition of Example 2 is diluted with water and tested as a wood preservative for its activity against various Basidomycets fungi by the method of British Standard No. 838 (1961). The wood blocks used in the sample are kept under vacuum of less than 10 mm Hg for 10 minutes, the diluted preparation is added and the blocks are allowed to soak for 2 hours. The blocks are weighed to determine the amount of preparation taken. The toxic limits of the various fungi are given below, expressed as the amount of weight of preparation (containing 10% TBTO) per day. m tree. These results are compared in the table with similar results obtained for a conventional copper chromar arsenate preparation prepared from 27.6% CuSO ^, 5H₂O, 35.4% and 37.0% Na₂HASO ^, 7 ^O added to adjust the pH of 2, 5th The toxicity limits of the latter preparation are stated as the amount of BS 4072 type 2 expressed as solids.

16 144695

married limits

Poria Lenzites Polystictus monticola trabea versicols 1. Organotin preparation of Example 2 not washed out -C 0.74 0.75-1.20 0.97-1.59 washed out <.0.74 1.19-1.85 2.52- 3.90 2. Copper chromar arsenate preparation_ not washed 2.93-4.83 3.09-4.86 1.61-2.64 washed out> 7.55 2.95-4.88 3.78-5 , 47

These results show that the diluted aqueous composition of Example 2 is better as a preservative than the conventional inorganic composition, especially when Poria Monticola is the major wood-destroying fungus present.

Claims (4)

17 144695 Patent Claims. A method of preserving cellulose material in the form of wood or a solid wood product not substantially infected with wood-destroying fungus, wherein the cellulose material is treated with an organotin compound having three alkyl, cyclohexyl and / or phenyl groups attached to a tin atom through Sn C-bonds, characterized in that the treatment of cellulose material is carried out with an aqueous system containing 0.01-0.4% by weight of the triorganotin compound and 0.02-5% by weight of a monoquaternary ammonium compound in a sufficient amount to disperse the triorganotin compound under the treatment conditions. , providing an uptake of 0.15-1.5 kg of triorganotin compound per m wood or wood product. Process according to claim 1, characterized in that the triorganotin compound is tri-n-butyltin oxide. Process according to claim 1 or 2, characterized in that the monoquaternary ammonium compound contains 2 methyl groups and either a benzyl group and an alkyl group of 8-18 carbon atoms or an alkylbenzyl group having one alkyl bond having 8-18 carbon atoms and another methyl group. Process according to any one of the preceding claims, characterized in that the weight ratio of triorganotin compound to quaternary ammonium compound is from 1: 2 to 1: 6. Process according to any one of the preceding claims, characterized in that the cellulose material is first subjected to a pressure under atmospheric pressure, then contacted with the aqueous system in the form of a dispersion or emulsion, after which the pressure is raised to above atmospheric pressure while the material is still in contact. with the aqueous system, after which the pressure is brought to atmospheric pressure and the dispersion or emulsion is removed, whereupon pressure and residence times are adjusted after the absorption of preservative in the cellulose material.