DE2710530A1 - PROCESS FOR IMPRAEGNATING WOOD - Google Patents

Description

The present invention relates to a method of impregnation of wood and other porous materials with impregnating agents. It relates in particular to a method and preparation for impregnating wood and other aellulosic materials porous materials with impregnating agents to preserve these materials.

Impregnation agents, including wood preservatives, flame retardants, Dyes, water repellants and other preparations for treating wood are already safe for wood inflicted many years ago. The level of penetration of the impregnation agent in the wood varies from treatment to treatment. The oln achieved maximum penetration Oohandlunn. is nine OrucU-bphandlunti. Here iuirri ο in positive tiuOi> rnr pressure ηι, · Γ ii.- ;; Men ν

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BATH ORIGINAL

applied to the impregnation liquid into the wood pores to force. Many pressure treatments usually become a flowable one Impregnation agent used, which consists of an impregnation agent dissolved in a solution. The solution can be from certain solid organic compounds that are dissolved in petroleum distillates or consist of halogenated hydrocarbons.

There are certain inherent disadvantages when using a waterproofing agent is applied to the wood in such a non-aqueous solution. One of them is migration, a phenomenon in which the impregnation agent after application into the wood due to migration of the remainder remaining in the wood Solvent migrates to the peripheral wooden surfaces. Another disadvantage associated with hiking is "blooming" ("blooming") · With this phenomenon, the impregnating agent deposited in the wood crystallizes out of the solvent the surface of the treated wood. This phenomenon is believed to be due to the migration of the solvent in the treated Wood on the surface of the same effects, the migrating solvent entrains the dissolved impregnating agent, which on crystals on the surface of the treated wood. There a Part of the waterproofing agent lost due to blooming the amount of impregnating agent used for treating the wood must be used be greater than the amount that is to be retained in the wood. In addition to being wasteful, this leads to problems in doing Treating thin pieces of wood with impregnating agent using a volatile solvent. Furthermore, it is difficult to obtain a treated wood with a regulated distribution of the

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To preserve impregnation agent within the treated areas "

Attempts have been made in the past to overcome some of these drawbacks Use of anti-blooming agents or by removing the solvents from the wood after the impregnation agent eich was in the wood to overcome. Anti-blooming agents usually have relatively high viscosity and high solvent power for the impregnation agent and do not evaporate easily from the wood. Furthermore, these agents contribute to water removal

etoOung and act as co-solvents. typical means against blooming, if the impregnant was pentachlorophenol, are polypropylene glycol, trixylyl phosphate, linseed-61, Eetergum, "long oll alkyd resins" and o-dichlorobeneol. Removal of the solvent from the treated wood, of course, leaves only the impregnant in the treated wood Wood back. The recovery of the solvent reduces the blooming rate and makes an impregnation process by incorporation tourer solvents that can be reused, more economical, but if the solvent is removed, leads • 8 something impregnating agent with you «AuGerdam it is difficult to .to remove all the solvent because «in tall of the same Trapped in wood is retained, causing blooming after the treatment leads.

There are various methods in which the impregnation agent In essence, it is a preservative in the wood is sealed off by a pressure impregnation treatment in order to protect the Disadvantages of wandering and blooming possible to verrlngorn. at such a method (US PS 3 200 003) is HoIs with a

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Impregnated solution, which consists of a carrier, a Kolüsungsinmittel and a preservative. The carrier is an aliphatic hydrocarbon solvent with a boiling point below that of water, which liquefies readily and which contains the preservative aid in the solution. The cosolvent has less than 10 % water solubility and greater than 25 % solubility for the preservative and a solubility in the solvent used as a carrier for the preservative. For example, the preservative pentachlorophenol, dissolved in isopropyl ether as a cosolvent, can be used, both of which are dissolved in the common liquid carrier butane.

A pressure treatment using a solvent as a common liquid carrier for the preservative is the Can. PS 863 885. It teaches the impregnation of wood with a flowable material containing a halogenated carbon dioxide solvent and optionally one or more modifiers; The modifying agents are chemical compounds and resins which are soluble or dispersible in the solvent and which are non-volatile ^{below about 121 ° C.} Such modifiers are, for example, polymerizable components such as styrene, acrylic monomers and copolymers for dimensional stabilization, flame retardants for thermal protection, dyes for coloring and preservatives for protection against decomposition. All modifiers are soluble in the halogenated hydrocarbon solvent, which acts as a common liquid carrier. After that

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If flieObara material has penetrated the wood, the halogenated one becomes Solvent it by heating the impregnated Wood removed with steam.

Another pressure treatment using a solvent US Pat. No. 3,7B5,770 describes a common liquid carrier for the impregnating agent. A wood treatment preparation It is produced by treating wood with pentachlorophenol, which is dissolved in a white spirit with a narrow boiling range, which acts as a solvent carrier. A small amount of polypropylene glycol is used as an anti-blooming agent and a carbon thermoplastic resin as a water repellant agent added. Furthermore, dioctyl phthalate is added as an aid in suppressing exercise. After this If the wood treatment preparation has impregnated the wood, the white spirit solvent will be used removed from this.

The impregnation of wood with an impregnation agent after the pressure treatments described above is intended to reduce efflorescence, however, the wood treated by these methods usually has to be washed after impregnation in order to remove some of the bloomed ones Remove particles that are present immediately after impregnation

It is well known that wood can be mixed with vinyl monomers such as styrene, methyl methacrylate, Acrylonitrile and vinyl acetate are impregnated. These monomers are then polymerized in situ to improve the dimensional stability of the wood. The polymerization takes place by the action of high radiation energy or a thermal decomposition of a chemical, r'roien niuUkal-Vorlaufnr3, such as

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Benzoyl peroxide.

In the past there has been no method for impregnating Wood developed with an impregnation agent, in which one Controlled distribution of the impregnation agent in the treated wood with little or no blooming is achieved. The above Method of US PSS 3 200 003 and 3 785 770 and Can. PS 863 885 are intended to reduce the blooming that treated wood must however, washed after impregnation to remove some of the bloomed Remove particles that are on the wood surface immediately appear after impregnation. Furthermore, the treated wood is not subject to blooming after this treatment all solvent that becomes a common liquid carrier can be removed during the process.

The aim of the present invention is to provide a method and preparation for a more permanent deposition of an impregnation agent in the wood through a controlled reaction, the sine better restraint and controlled distribution of the Impregnation agent in the wood and reduces the degree of efflorescence with the associated loss of impregnation agent, facilitates the recovery of the common liquid carrier and the need to wash the treated wood bypasses without affecting the strength or appearance of the wood.

According to the invention, it was found that an impregnation agent for wood can be deposited into the wood permanently with regulated distribution and long-term effect if the impregnation agent after penetrating the wood from dom odor the lubricant (s) _#

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which are removed for easier penetration into the wood, immobilized will. The method according to the invention relates very generally the wood treatment with 8inem single-phase, non-aqueous, an impregnant and a reactive solvent containing system, so that both impregnating agent and reactive Solvent penetrate into the wood, whereupon the reactive solvent is reacted, so that the impregnating agent is practically insoluble in this. For easier penetration into the wood, a liquid carrier can be used with the impregnation agent and reactive solvents are used; the reactive solvent is in this liquid carrier soluble, while the impregnation agent in this is practically insoluble.

The impregnating agent used in the process according to the invention are wood treatment agents, used to protect the wood Damage and decomposition are incorporated into theeaaa. Such wood treatment agents Bind e.g. preservatives, flame retardants ■ materials, dyes, detergents and others Wood treatment preparations. There is such an amount of impregnation agent used, "ie aie necessary for the effective treatment of the Holzaa iat. Wirkaan iat aina aolcha slope that suffices dam HoIx preserving, flame retardant, colored or water abetoBende To give properties. The irkeame amount of impregnating agent varies depending on the impregnation agent used and the end use of the impregnated wood. Oie «Irkeame amount for a special waterproofing agent and one

special end use can be determined by determination (Threshold value)

the limit value of this impregnation agent for the rubble of

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Blocks in the ground are determined. Then the effective amount is at least the same or close to the limit value. The limit value for blocks in the ground can be taken, for example, from "American Wood Perservers ¹ Association Standards" and "American Wood Preservers 'Association Journal", "British Wood Perservers' Associations Standards", "Forest Product Research Society Journal", "Journal of Wood and Fiber "," Journal Institute of Wood Science "and" Wood Research "are noted.

The reactive solvent is a non-aqueous compound or a mixture of compounds which keeps the impregnating agent in solution and which can be reacted in such a way that the impregnating agent becomes practically insoluble in the reacted reactive solvent. Will be impregnant and reactive Solvent only used to penetrate the wood, then the impregnating agent is reactive Solvent soluble. In addition to the solution of impregnation aittal and reactive solvent, it becomes a liquid carrier related, then the reactive solvent keeps the impregnation

non-aqueous
impregnating agent in / drai component system made up of impregnating agent, reactive solvent and liquid carrier. The reactive solvent is soluble in the liquid carrier, while the impregnating agent is practically insoluble in this. Typical reactive solvents include, for example, water-insoluble polymerizable monomers, insoluble, complex-forming agents and decomposition product-forming agents. An amount of reactive solvent is required that keeps the impregnating agent dissolved before the reactive solvent reacts. The impregnation agent is immobilized, indom os in the surrounding

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set reactive solvents and used liquid Carrier is practically insoluble.

The liquid carrier optionally used should be an inert liquid in which the reactive solvent soluble, but the impregnating agent is practically insoluble. Further, the liquid carrier should have a low viscosity and a high degree of penetration into the wood, which is required at least such an amount of liquid carrier as is necessary for dissolving of the reactive solvent is necessary.

The wood can, according to the method according to the invention, at atmospheric or superatmospheric pressure. In the case of over-atmospheric pressure, a full or Empty cell method can be used. The contact must take place in such a way that the wood penetrates or impregnates is possible by impregnating agents and reactive solvents.

The reactive solvent is reacted so that the impregnating agent in the reacted reactive solvent and the liquid carrier as well as all other solvents used is insoluble except for the reactive solvent. The reactive solvent is a polymerizable monomer or a mixture of these, then it can be reacted by exposing the impregnated wood to high energy radiation or exposure to heat. In addition polymerization, the amount of high-energy radiation necessary for the polymerization can be used or heat has been reduced by using an initiator. This use of an initiator can reduce the possibility of damage to the wood by dio hoho, nob-

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Prevent maneuverable amounts of high radiation energy or heat. The initiator need not be a real catalyst, including a Part of the initiator takes part permanently in the reaction and is chemically combined in the polymer obtained. The initiator may cause decomposition due to heat or decomposition ale photo-8en8ibilieator under the influence of a photon for the conversion of the surface layer or a decomposition by Clementare particles high energy, such as electrons, protons, tX particles or neutrons, subject. This decomposition forms free radicals which attack the monomer with the formation of polymers. To Formation of the polymers keeps the converted, reactive Solvent the impregnant is no longer in solution; therefore the polymer is a nonsolvent for the impregnating agent.

When using a liquid carrier with the impregnating agent and reactive solvent, the carrier is removed from the treated wood after the reactive solvent becomes a non-solvent for the impregnant. The reactive solvent is soluble in the liquid carrier, the non-solvent or reacted reactive solvent however, may or may not be soluble in liquid carriers.

If a reactive solvent is used, which according to his Implementation to «non-detaching agent for da · impregnation agent im Wood will. then a wood product is obtained which contains the impregnating agent and reacted reactive solvents contains. The door touching the wood pinch making a The solution used for such a product consists of an impregnation agent, that in the solution of a reactive solution

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by means of galöet. If a liquid carrier is used the touch solution from one im the solution of the reactive Solvent-dissolved impregnation agent, the solvent being soluble in the liquid carrier, the impregnation agent However, it is practically insoluble in the carrier. The touch solution can also use co-solvents to better dissolve the reactive Solvent contained in the liquid carrier or, for better dissolution of the impregnating agent, in the reactive solvent

The impregnating agent used in the process of the invention for treating wood is usually a preservative or flame retardant; The other can be one of the solvent-soluble toxic preservatives, often referred to as toxic salts. These toxic salts, some of which are not salts in the technical sense, usually include the so-called ^{preservatives contained in Ul (n} oil-borna ^N ). Solvent-soluble toxic preservatives include chlorinated organic

Compounds, organic metal compounds and inorganic compounds

eg am fertilizing. Oils chlorinated organ laughing compounds include / pent · - chlorophenol, 2,4-dinltriochlorobenzene, chloronaphthalene, 1-chloro-ßnaphthol, 2,4-chloro-«f-naphthol, trichlorobenzene, tetrachlorophenol, 2,4,5-trichlorophenol, 2 , 4,6-trichlorophenol, chloro-2-phenylphenol, 2-chloro-4-phanylphenol, tetrachloronaphthalene-pentachlorophenol and 1 f2,3,4,10,10-Hsxachlor-ö ^ -epoxy-1, 4,4a, 5, β , 7,8, Ba-octahydro-1 _f 4-ando _t e »o-5,8-dimethannaphthalln ( ^M Dialdrln ^N ). Organic metal

z. B.
compounds include / copper naphthenet, Xupfftrraainat, Kupferabiertlnat, Zlnnaphthanat, Zinc resinet, Zlnkabietinat, Ethylmarcuriacatat, Xthylmsrcurichlorld, Xthylmcrcurloleate, Phsnylmercuri-

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acetate, phenyl mercury chloride, phenyl merucrioleate, solubilized Copper B-quinolinolate, copper pentachlorophenol, pentachlorophenol zinc naphthenate. Sodium pentachlorophenate and tributyl tin acetate and tributyl lead acetate and tributyl tin oxide.

When a polymerizable monomer is used as a reactive solvent, the monomer is a solvent for the preservative. In being a solvent for the preservative, the reactive solvent contains the preservative and maintains it in solution in a non-aqueous three component impregnation system of preservative, reactive solvent, and liquid carrier. Any water-insoluble monomer which is a solvent for the preservative and which can undergo addition polymerization, condensation polymerization, homopolymerization, mixed polymerization or ionic polymerization can be used as the reactive solvent. If the preservative is, for example, pentachlorophenol, then suitable polymerizable monomers are, for example, styrene, vinyl acetate, acrylonitrile, butyl acrylate, methacrylonitrile and methyl acrylate. Mixtures of these compounds, such as styrene / acrylonitrile, can also be used. Furthermore, a co-solvent can be used to better dissolve the pentachlorophenols in the polymerizable monomer. Good cosolvents are methanol, toluene, benzene, nitrobenzene, di- and trichlobenzenes, alkylbenzenes, hydroxybenzenes, xylene, ethyl ether, isopropyl ether, vinyl ethyl ether, oibutyl ether, dibutyl ketone, diisobutyl kotone, diisobutyl kotone, methyl isobutyl kotone, methyl isobutyl ketone, isobutyl tetromeric, isobutyl tetromeric, isobutyl kotone, isohydric butyl ketone, polymeric, butyric alcohol that act as reactive LüiajnQGmittal. Is dao Kulöaungamittol no roaktinnrf; H) tc) f! 3 I üsungr.nitlel, then fJlo takes effectiveness dns urf trulunnugnmiUlnn \ / nrrrihr '; r): ". Nb.

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This can manifest itself in a small amount of blooming, however, this is still an improvement over known methods represents.

Other specific preservatives or flame retardants can be used with suitable monomers. Thus, tributyl tin acetate or tributyl lead acetate can be used with styrene, acrylonitrile, methacrylonitrile or mixtures thereof. The preservative "Oieldrin" can be used with monomers such as vinyl acetate, acrylonitrile, butyl acrylate, methacrylonitrile or methyl acrylate or mixtures of these compounds. The dibasic magnesium phosphate can be used as a flame retardant with the reactive solvent acrylonitrile and the liquid carrier pentane. 9 wt -.% pentane and 0.1 Cb <b "-% benzoyl peroxide. Preservatives that can be used in conjunction with specific monomers and. Flame retardants are not a limitation of the present invention. Any non-aqueous, polymerizable monomer can be used for any solvent-soluble impregnating agent, as long as the latter is soluble in the monomer.

For monomers which are subject to addition polymerization, initiators such as peroxides such as acetyl peroxide, benzoyl peroxide and lauroyl peroxide, or hydroperoxides such as cumene hydroperoxide and azo compounds such as 2,2'-bis-azoisobutyronitrile can be used. These initiators decompose under the influence of heat or Elamuntartoilchen high energy, uiiu electrons, protons, <-

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Particles or neutrons, with the formation of free ones, the polymerization Initiating Radical Monomers · Certain vinyl-like monomers do not respond to free radical initiation} but this one Monomers such as propylene, isobutylene and most vinyl ethers can be initiated by Friedel-Crafts catalysts. Such known catalysts are boron trifluoride, aluminum chloride, Stannous chloride and aluminum bromide, with cocatalysts such as Water and Acetic Acid * Other known initiators can also be used.

The one for easier impregnation of wood with the reactive Liquid carrier used in solvents and preservatives is a non-aqueous compound in the liquid state in which it is used the reactive solvent is soluble, the preservative but is practically insoluble. This liquid carrier should be easy to recover and, if necessary, again to be used. Such liquid carriers are aliphatic Hydrocarbon compounds with a boiling point below that of water at atmospheric pressure, which are at normal Easily liquefy at temperatures and elevated pressures. Is pentachlorophenol the preservative, then the liquid carriers are e.g. liquefied petroleum gas, liquefied propane, butane, Isobutane and pentane. The pentachlorophenol can be liquid in these Slightly soluble in inertia. This solubility is insignificant enough to describe the pentachlorophenol as practically insoluble in these compounds. Other liquid ones, with special ones Carriers that can be used for impregnating agents are aromatic hydrocarbons, Petroleum distillates or any to the impregnant and reactive solvent inert liquid,

IrT which the impregnating agent is insoluble.

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Impregnation agent and reactive solvent are used usually added to the wood in conjunction with a liquid carrier; you can also use the wood directly without a liquid carrier be admitted, which is however costly. Using a liquid carrier reduces the amount of reactive Solvent. The liquid carrier can also be recovered and used again.

The non-aqueous three-component impregnation system Impregnation agents, reactive solvents and liquid carriers can be applied to the wood using the full and empty cell process be added. This solution system must bsi under pressure injected into the wood at a temperature below the temperature required for the reactive solvent to react lies. If more heat were used, the reactive solvent would penetrate the wood from maximum penetration or even possibly react before any penetration of the impregnant into the wood.

The empty cell process allows sines to be recovered Tail of the liquid carrier that can remain in the wood after its substantial part has been removed by volatilization. This remaining liquid carrier also becomes wood through expansion a non-condensable gas removed before the inoculation agent, reactive solvent and liquid carrier has been brought into the holt. As a non-condensable gas can be used compressed · air. However, since the liquid carrier can be flammable, an inert gas, such as nitrogen, be used. In the empty cell process, wood is placed in a pressure vessel, usually a horizontal cylinder,

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and in these an inert gas, such as nitrogen, is introduced before the impregnation solution introduced. In this way, a cushion of inert gas forms within the wood under the impregnation solution.

_R then gepreQt vird an impregnation solution in the cylinder and the timber whereby prints can be up-to 7-14 kg / cm applied to bring deep into the wood to the Imprägnierungalösung. Pressure is maintained even while the impregnation solution is removed from the cylinder. The wood is still completely saturated with solution and heated under pressure for sufficient time to cause the reaction of the reactive solvent; it can be heated in the usual way. Suitable heating media include hot butane vapors, hot liquid butane, water or steam. The high pressures in the wood prevent any water absorption and allow the treatment to be dry. After reaction and immobilization of the reactive solvent, vapor recovery and vacuum phases can be used to recover as much liquid carrier as possible. A vajoium is applied so that the compressed inert gas in the wood cells expands and the remaining liquid carrier is forced out of the wood. There is no loss of impregnant in this process because it is practically insoluble in the liquid carrier and the reacted reactive solvent. Depending on the type of reactive solvent used, some, all, or no solvent may be removed with the liquid carrier.

In the case of the full cell ancestor, _{the Molz ΒΓ)} thai tonclo vessel is initially exposed to a high vacuum. Einn impriign in

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Ca,
Solution is placed in the cylinder and surrounds the wood, maintaining the vacuum. Positive pressure is then applied to introduce the impregnant along with the reactive solvent and liquid carrier into the wood. This positive pressure stage is a modified heat-pressure stage, ie the amount of heat used should not exceed the heat required for the reaction of the reactive solvent. If the necessary positive pressure cannot be achieved by using the limited amount of heat, another method must be used to develop the pressure. The positive pressure is maintained to allow the impregnation agent, solvent and liquid carrier to penetrate the wood. The cylinder is emptied while maintaining sufficient pressure to hold most of the permeated impregnant, solvent and carrier in the wood. The cylinder is then heated to allow the reactive solvent to react and the impregnant is immobilized in the wood. The cylinder is cleared of the heat transfer medium, which can be any known medium. The vapors are recovered in the usual way and a final vacuum can be applied to evaporate most of the liquid carrier from the wood.

In a preferred implementation of the process according to the invention for preserving wood, pentachlorophenol is used as the impregnation agent, acrylonitrile as the reactive solvent and liquefied butane as the liquid carrier. Iodine amount of pentachlorophenol can be vortexed, but usually 5 C, ew .- / <, of the entire solution for the purpose of treating the Hogon decomposition.

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At least such a quantity of Acrylni tril is required that solubilizes an effective amount of pentachlorophenol. The amount of acrylonitrile dissolving 5% pentachlorophenol is at least 7 % by weight of the total solution, preferably 8-12 %, in order to avoid problems with the precipitation of the pentachlorophenol. This solution can be heated for a short time under mild conditions for the same purpose. The amount of butane used is in the range that is necessary to dissolve the acrylonitrile, ie usually between 79-ΒΘ% by weight ,

An initiator is used to polymerize acrylonitrile under relatively moderate conditions; of the known initiators, lauroyl peroxide is preferred. V / is erwendet provides such Lauroylperoxidmenge, the favorable decomposition properties between 20-100 ⁰ C.. The preferred amount of lauroyl peroxide is between 0.05-0.80 % by weight of the three-component system. Another suitable initiator is the azo compound azobis-isobutyronitrile.

The rate of decomposition of this azo compound is somewhat slower than lauroyl peroxide at the same temperature. Therefore longer heating times or higher temperatures may be necessary when azobisisobutyronitrile is used as the initiator.

The above three-component system of 5 % pentachlorophenol, 7-12 % acrylonitrile and 0.05-0.80 % lauroyl peroxide and 79-88 % butane can be introduced into the wood using the Lear or full cell method. Since acrylonitrile is present in the solution, the process should be carried out in a facility that does not contain copper or brass, as acrylonitrile corrodes these metals and copper in the solution with pentachlorophenol forms a red complex precipitate, which leads to a loss of pentachlorophenol from the impregnation system leads.

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The full cell method is preferred. The wood to be impregnated is placed in a hermetically sealed pressure cylinder, this is flushed through to less than 3% to remove oxygen in order to avoid the explosion area with butane, then a vacuum is applied to the wood to remove all of the non- Condensable oases created from the wood cells to prevent the penetration of as much preservative as possible

to enable. Any initial deposition of pentachlorophenol in the cylinder must be avoided by prior introduction of pure butane into the same, until the equilibrium vapor pressure of Impregnation run like at the boiling point is reached The cylinder is made with the above-described, non-aqueous Three-component impregnation system filled by mixing of pentachlorophenol with acrylonitrile in the presence of heat to better dissolve the former and then dilute it Mixture with butane and addition of the polymerization catalyst is premixed. This is the preferred order of shuffling, which, however, can be varied. Then the pressure is done by means of a inert cases increased to the preferred value of 6.75 kg / cm. If necessary, further impregnation systems can be used during the process pumped into the cylinder. The pressure is maintained until sufficient pentachlorophenol is incorporated into the wood istr slide duration varies depending on whether a full one or almost complete treatment required and which type of wood is used

Let wood enough pentachlorophenol do Sahuti β · ο · η leraetzunf incorporated, then the cylinder is emptied, weave in higher pressure ele the vapor pressure of iutane is maintained,

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to keep the impregnation system in the wood when emptying the cylinder. Then the cylinder is filled with the butane acting as a heat transfer medium, only until the steam coils on the cylinder base are covered with the formation of hot butane vapors; or it is filled to completely cover the wood in order to heat it with hot liquid. The impregnated wood and / ill be heated to the preferred temperature between 60-85 ⁰ C.. At this temperature the lauro peroxide decomposes and initiates the polymerization of the acrylonitrile. The polymerized acrylonitrile is not a solvent for the pentachlorophenol, and this is practically insoluble in butane, so that the pentachlorophenol is immobilized in the wood. This immobilization allows a more permanent deposition of the pentachlorophenol in the wood. To recover as much butene as possible, a steam return and vacuum phase is used. A steam pump is used to remove the vapors in the cylinder. The steam pressure is reduced at such a rate that it does not damage the wood. After butene and all other gases in the impregnated wood have evaporated, condensed and discharged into a storage tank, the cylinder is subjected to a final vacuum to remove the last traces of hydrocarbons and then flushed with an inert gas to reduce the hydrocarbon vapor to less than 4 % . Then the cylinder is opened and the impregnated wood is removed.

Another embodiment is the empty cell process using a combustible gas. The wood is in ninen hermetically sealed cylinder qogoben, the air evacuated and and an inert gas, such as nitrogen, boi relatively nioriricjom pressure

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introduced and driven into the wood. After this gas impregnates the Droi component system made of pentachlorophenol, acrylonitrile and Butane hits the wood and creates a pressurized cushion of inert gas within the wood under the dissolution system. To Completion of the above impregnation and action cycle will be the Butane returned to the storage pressure tank. The amount of solvent retained in the wood during full cell treatment is lower than with known processes using organic Solvent, so that the solvent recovery takes place faster and the cylinder can be opened earlier.

The above empty and full cell methods provide a treated wood that contains an effective, wood-preserving amount of the pentachlorophenols immobilized in the treated wood. The treated wood also contains the polymerized polyacrylonitrile) this does not interfere with the effectiveness of the pentachlorophenol as a wood preservative and therefore does not need from the treated wood to be removed. That according to the above procedure treated wood contains pentachlorophenol and polyacrylonitrile, and its surface is clean and does not need to be washed to be subjected.

The following examples illustrate the present invention, without restricting them.

Table I shows examples of non-aqueous impregnation system formulations, those in the inventive method for wood treatment can be used.

In tests a to i, the Pentachlorphonolgoha It was 5.0 5 ^ kept what is customary in wood preservation; the pontachlor

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However, phenol percentage can also be above or below this value varies. Furthermore, examples are 5.0- ^ iger formulations other wood preservatives shown «The formulations of Table I was prepared by adding the reactive solvent and preservative at room temperature liquid carrier was added, the catalyst was added and the mixture was stirred for about 0.5 hour. The solution system obtained was clear with the consistency of the liquid vehicle and ranging in color from yellow to brown.

In the table below mean

BPO s Benzoyl peroxide LPO 3 Lauroyl peroxide AIBN «2.2 ^I -A2obt8isobutyronitrile

"Penta" means pentachlorophenol.

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Preservation agent Table I.

Formulation of impregnation mixtures % reactive. Solvent catalyst;

% liquid carrier;

5.00 % penta 8.00 Acrylonitrile S. If if
• t * η 11.00
10.00. η
η d) With 13.7 Methacrylonitrile e) «W 2.0 Styrene 7.0 Acrylonitrile f) N ■ 40.00 Styrene G) W ti 14.00 Vinyl acetate H) ti It 16.00 Butyl acrylate i) ft N * 13.5O Methyl acrylate J) 5.00 % tributyl 15.0 Styrene tin acetate k) 5.00 % dialdrin 10.0 Methacrylonitrile 1) ■ N 15.0 Vinyl acetate

BPO

LPD AIBN

LPO BPO

BPO BPO LPO LPO

LPO

LPO LPO

0.20 pentane

0.22 butane 0.20 η 0.28 Pentane 0.20 butane 0 80 Pentane 0.30 η 0.32 It 0.27 ti 0.30 If 0.20 ti 0.30 ti

86.80

83.78 84.80

81.02 85.80

54.20 80.70 78.64 81.23 79.70

84.80 79.70

Ba lap ia 1 1 ' % i .

Southern yellow pine (SYP) blocks were made according to the full-cell method in the laboratory scale

a pressure hydrometer beaker treated as a treatment acy linder. Here, SYP blocks of 1.6 era were treated with 5- ^ pentachlorophenol solution using pentane as the liquid carrier and a styrene-methanol mixture or a styrene-acrylonitrile mixture as the reactive solvent. After the initial vacuum period, pure pentane was introduced until the equilibrium vapor pressure was reached. Enough solution was introduced to cover the blocks. The pressure was increased to atmospheric or 1.05 ata and held for 30 minutes. The impregnation solution was drained and pentane was introduced to the bottom of the cylinder, taking care not to touch the blocks. The entire device was then heated in a hot water bath to 70 ^° C. for 2-4 hours. The hot pentane vapors formed heated the blocks and caused the solvent to react. After the above treatment of the blocks, no surface crystals were visible. Table II presents data from X-ray analysis showing the retention of the pentachlorophenol in the blocks treated as above. The blocks treated in this way showed no surface crystals and also no blooming; they were clean, dry, natural in appearance, and did not need to be washed.

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reacts. Probation
solution in a 5
1.6 Table II Geui.to
reaction
c. Beutahr.anPenta-
chlorine ^ henol Probation*
(pcf) Styrene capable solvent Weight before
Hand 1
G - 3.95 1.26 test π Methanol 4.84 4.65 4.45 1.42 1 It Il 4.47 % Impregnation agent containing pentachlorophenol
cm SYP blocks 4.75 4.80 1.53 • ι Styrene It 4.49 Geui.to
. Hand 1. 5.29 3.67 1.17 3 η Acrylonitrile 5.04 8.66 4.85 4.07 1.30 4th N ti 4.63 8.44 5.03 3.57 1.14 VIl η 4.81 8.81 5 8.76 8.42 8.24

based on the kiln-dried weight of the southern yellow spruce of 32 pcf (pound
per cubic foot)

-> ο cn co O

BB 1 ap 1 J 1 2 '34 »

Douglas fir core wood used to simulate the treatment of Usual lumber was sealed at the ends, was in one Cylinders with a diameter of 20 cm treated with the non-aqueous impregnation agent in a test facility · The impregnation agent was pentachlorophenol, the reactive solvent was a polymerizable monomer, and the liquid carrier Butane or pentane. The boards treated with this solution had clean surfaces and the appearance of untreated Wood. The results of the treatment of the Douglas spruce wood with an impregnation mixture are summarized in Table III. Each sample board was cut and examined for preservation by X-ray analysis.

The following abbreviations are used in Table III! ACR β acrylonitrile

Sty-ACR = styrene-acrylonitrile compound LPO s lauroyl peroxide
BPO s benzoy peroxide

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Table til

Board ^no * nominal dimensions; cm

PCP amount (% of total amount)

liquid carrier reactive solvent

initiator

^? Treatment cycle O ₀ initial vacuum (at inch Hg) *** pressure increase (min at kg / qm ^) ** «· pressure maintained; min at kg / fcm ^ a temperature? std at °

Result se

10x10x60 10x10x60 _m ACR .10x10x90 5x10x60 - 5x10x60 5x10x60 5.0% 4.5% LPO 5.0% 4.5% 4.0% 4.0% - butane m ACR Sty-ACR ACR Sty-ACR ACR LPO BPO LPO BPO LPO ■ 5n_9Q »<3u— co *
- 15-δ, 75 - 30-8.75

'C. 2.25-76

1.5-79

4.0-82

4.0-above

2.0-85

3.0-82

Appearance of the surface Treat. 0 .48 0 .39 0.55 0. 31 0 .38 0 .30 ■ ts
¹ S ο Custody; pfc 0 .53 0 .30 0.55 0. 33 0 .35 0 .33 • co 0-6 mm 0 .48 0 .08 0.56 0. 33 0 .32. 6-12.5 ram 12.5-25 mn
* carried out after
procedure the empty cell

None represents boards showed after treatment surface crystals · For these boards, the temperature murders kept at least 76 ⁰ C * at least 1.5 hours. This time and temperature are sufficient to convert all of the reactive solvent and thus prevent the formation of surface crystals on the boards.
Example 3

Three further tests are carried out in cylinders of 90 and 45 cm 0 to determine the applicability of the method according to the invention to the treatment of piles. The impregnation mixture consisted of 3.6-4.7 % pentachlorophenol as the impregnating agent, 7-12% AcryHLtril as the reactive solvent and 83-89 % butane as the liquid carrier along with 0.15-0.25 % oenzoyl peroxide as the initiator for the polymerization.

In the test series, 1 »8 m pile sections were treated. The total volume of these sections varies between 0.071-0.091 m. The piles were sealed at the end prior to treatment to keep penetration at the ends to a minimum and to simulate the treatment of a common material. Douglas fir trees were used because this species has the most severe crystal bloom problems. A set of southern spruce piles was also dealt with. The results are shown in Table IV.

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Table IV Bauehrong in Rome in the test zones

"J Stake Species pressure Time Temp. Time 0-6 6-12.5 12.5-25 25-38 38-50 50-62.5 O No.* atü hours ⁰ C. hours pcf ** UO
co
u> 1 SYP 8.75 " 1.0 82.22 4.0 0.38 0.37 0.39 0.39 0.36 0.38 OO
-χ » 2 D. F. 1.0 82.22 5.0 0.69 0.70 0.79 0.74 0.63 0.31 O 3 D.F. ". 1.0 82.22 10.0 0.73 0.61 0.67- 0.65 0.69 0.47 (O 4th D.F. ; · - 1.0 82.22 6.0 0.64 0.68 0.67 0.55 0.61 0.51 5 D.F. "-. 1.0 82.22 4.0 0.41 0.28 0.20 0.11 0.08 0.0 ^! 6th D.F. "r 1.0 82.22 1.0 0.56 0.22 0.13 0.11 0.02 0.006 7th D.F. ": 1.0 82.22 3.0 • 0.77 0.47 0.42 0.3B 0.41 0.12

Post 1-4 was impregnated using the full cell method

Pile 5-7 was impregnated using the partial empty cell method based on an average density of Douglas spruce of 28 pcf and

southern spruce of 32 pcf

Ca) O

B β ia pi et 5 - 3 * '

Four SYP blocks of 16.3 min were impregnated with an impregnation mixture of 5 % pentachlorophenol as preservative, acrylonitrile as reactive solvent and butane as liquid carrier. After treatment, the three blocks were placed in an oven at temperatures of 50-90 ⁰ C. for up to a week. This confirmed that there was no post-treatment blooming or crystal formation on the surface of the blocks during the one-week observation at elevated temperatures. A block was cut into pieces and examined for pentachlorophenol by X-ray analysis. Then the pieces were subjected to a leach test; the pieces were in distilled water for 2 hours. Soaked in water, heated in an oven at 50 ^° C. for 6 hours and kept at room temperature for the rest of the day. This 24 hour cycle was repeated for 3 weeks. After the end of the test, the pieces were subjected to pentachlorophenol analysis to determine the loss thereof. The results are listed in Table V and show that only a small amount of PCP was lost.

more original % Tabel V salary Pieces of salary 2.35 PCP final PCP Sample A 2.61 % by 2.12 pcf 2.23 0.71 1 2.10 0.75 2.46 0.78 2 0.83 2.06 0.65 3 0.68 1.96 0.63 4th 0.67

based on an average density of the dry SYP of 32 pcf

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B e 1 "ep ie 1 6 ^ 1%.

To prove that the impregnation agent is due to pentachlorophenol the method according to the invention is not rendered ineffective, Teet were done on blocks in the ground to ensure effectiveness to determine the pentachlorophenols by treating blocks Suspended Lenzites trabea for weeks. Noticeable weight loss would indicate disintegration of the blocks by the organism.

A number of blocks for the floor were treated with the impregnation mixture of pentachlorophenol, a mixture of styrene / methanol in a weight ratio of 7t 2 as the reactive solvent with methanol as the cosolvent and pentane as the liquid carrier. The test series consisted of three sets of blocks. The first were treated with an impregnation mixture with a pentachlorophenol concentration of 2.0%. The second and third sets were treated with an impregnation mixture with a pentachlorophenol concentration of 1.3 and 0.6 %, respectively. A fourth set of blocks was treated with the styrene reactive solvent but without pentachlorophenol. A fifth set of blocks was left untreated and served as controls. The Handling of the Blocks Each set was subjected to the Americah Wood-Rreeervera Association (AWPA) standard two-week weathering cycle set out in the "Proceedings Sixty-nlneth Annual Meeting of the American Wood-Pereeervere * Association", American Wood-Preservers' Association, Washington, DC, vol. 69, p. 116. A weathered and non-weathered air lock from each set was ground and examined by X-ray analysis for pentachlorophenol content. Due to the different solution absorption of the different sheets, the results of the '

709831/0770

Rtlntgananalyaa can only be used as a control of approximate pentachlorophenol retention. An analysis of all individual blocks for pentachlorophenol retention was carried out at the end of the test. The remaining unground and analyzed blocks in each set were equilibrated at constant temperature and humidity, weighed and exposed to Lenzites trabea for 12 weeks and reweighed after 12 weeks of incubation. Every loss of more than 3 % leads to disintegration by the organisms · The slight increase in weight is irrelevant and is based on the different moisture content of the blocks. The unaffected blocks had a retention between 0.13-0.33 pcf. The results are summarized in Table VI.

In the table below mean Group A - 2.0 % pentachlorophenol treatment solution

Group B - 1.3 % "Group C - 0.4 % " Group D - 0.0 % "^

W - weathered U ■ unweathered

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1
2
3
4th block Weight in q before after 5,028
5,380
4,743
4,772 . 3 ** - - weight Veruiitt. 2710530 No. d.Bohandl. 4,853
4,337
5,206
5,150 Table VI . lost sentence 5,052
5,429
4,744
4,795 4,757
4,743
5,159
3,778 Weight · f. Keep silent 1
2
3
4th 5,023
4,356
5,198
5,188 1,667
3,452 lose 0.5
0.9
0.
0.5 U
U
W.
W. X-ray analysis 1
2
3
4th 4,930
5,226
5,508
4,867 2,520
1,438
1,301
2,664 3.4
0.4
+0.2
0.7 U
υ
* W
W. f> .- B ^e ^ 3ndl- per A.
A.
A.
A. 1
2
3
4th 4,345
5,499 0.024
0.049
0: 001
0.023 3.5
9.2
6.3
22.2 U
U
M.
W. 0.27
0.20
0.33
0.30 B.
B.
B.
B. 1
2 4,405
4,400
4,249
4,091 0.170
0.019
♦ 0.008
0.038 61.6
37.2 U
U 0.130
0.167
0.199
0.213 O O OO 0.173
0.483
0.349
1,089 42.8
67.3
69.4
34.8 U
U
W.
W. 0.113
0.093
0.078
0.026 0
D. 2,678
2,047 - 1,889
2,962
2,948
1,427

Through the invention process, according to the full or Void process a beeaaree penetration, preservation and a more uniform treatment is achieved and, compared to known methods, blooming is prevented or significantly reduced. Although the inventive method is possible provides a more uniform treatment, ee can still achieve a concentration gradient of impregnation agent be used in wood. Main reason for the inventions Advantages allow the impregnation agent to penetrate the wood controlled reaction can be deposited. The waterproofing agent does not bind or separate into the wood dieeam when it first touches the wood. Impregnated mgomittol, LIQUID CARRIER AND REACTION «fHhiqos solutionomittol boiuogun himself

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into the wood, and after reaching the desired penetration u / earth because β reacted reactive solvents and the impregnating agent deposited in the wood. »-.,.,.,

■ ■ ■ -

709838/0779

ORIGINAL INSPECTED

Claims (1)

Iy- process for impregnating wood with an 'impregnation agent, characterized in that one a) an effective amount of a waterproofing agent and a reactive one Solvent, in which the impregnation agent is soluble, can penetrate into wood and b) converts the reactive solvent, so that the impregnation agent is no longer soluble in the reacted solvent and is therefore immobilized in the wood. 2 · - Method according to claim 1, characterized in that a liquid carrier is used in wood treatment, in which that reactive solvents are soluble and the impregnating agent is practically insoluble. 3.- The method according to claim 1 and 2 _r, characterized in that an impregnation agent, a preservative or flame retardant is used. 4 «- method according to claims 1-3, characterized in that old; reactive solvent one or more polymerizable monomers can be used in which the impregnating agent is soluble. 5.- The method according to claim 1-4 _f, characterized in that the wood treatment is carried out with the impregnation agent and reactive solvent at überatmosphärischsm pressure. 6, - Method according to claim IS, thereby ijoknnnzBirhnot, rlaCl dno reactive! Solvent durrh WnriniJzr-irsHtziirHj ei nc σ. ϊητ tin tiir :; νλκ'.τ cJur.h '.' Aermo ο ti or Πΐ: - »ι; ίι1υϋ ::: it Te" Jrhwi high ·; _· ICI! ^: "' ^! " ^{! l} 709838 / - (T 779 BATH ORIGINAL 7, - Method according to claims 1-6, characterized in that a Cosolvent for easier dissolving of the impregnating agent is used in the reactive solvent » B.- Method according to claims 1-7, characterized in that the converted reactive solvents is removed from the treated wood. 9.- method of impregnating wood with an impregnating agent, characterized in that one a) treating wood at superatmospheric pressure with an impregnation mixture containing an effective amount of an impregnation agent, a reactive solvent 'in sufficient Amount to solubilize the effective amount of impregnation agent and contains a liquid carrier, in ^ back up the reactive Solvent soluble and the impregnant is practically insoluble and the amount of carrier is at least sufficient to dissolve the reactive solvent, b) the reactive solvent converts that the impregnation agent is not soluble in the reacted solvent and is therefore immobilized in the wood and c) removing the liquid carrier from the wood. 10.- The method according to claim 9, characterized in that the impregnation agent is a preservative or flame retardant used tuird. 11 · - Method according to claims 9 and 10, rladirth gekennzeirhriut, dall as roactive solvent 1 one or more polymer ic i t; rl · '·; rc Monomers uerwenriot iunrdnn, in mole hon <hs ImprMnn irrunii · r. < i t! ! ΐΓ ..-. i ϊ :: ΐι i. L. 709838/0779 BATH ORIGINAL 12.- The method according to claim 9-11 »dadiich characterized that the reactive solvents due to thermal decomposition of an initiator or by bombarding it with particles of high energy. 13.- The method according to claim 9-12, characterized in that a Cosolvents are used to more easily dissolve the impregnating agent in the reactive solvent. 14.- The method according to claim 9-13, characterized in that as liquid carrier an aliphatic hydrocarbon compound with a boiling point below that of water used at normal atmospheric pressure, which is calibrated under elevated pressure Easily liquefied at normal temperatures and in which the reactive solvent is soluble, the impregnating agent however, is practically insoluble. 15.- The method according to claim 9-1A, characterized in that the liquid carriers are removed and / or removed from the wood by evaporation. 16.- The method according to claim 9-15, characterized in that the rotation Reacted reactive solvents are removed from the treated wood. 17 - method of impregnating wood with a pentachlorophenol, characterized in that one a) the wood at superatmospheric pressure with an impregnation mixture, the pentachlorophenol in an effective wood treatment amount, a reactive solvent selected from the group of styrene, vinyl acetate, acrylonitrile, butyl acrylate, methacrylonitrile, Methyl acrylate and mixtures thereof and a liquid carrier from the group of butane and Fbntane in at least one 709838/0779 sufficient amount to dissolve the reactive solvent and a polymerization initiator from the group of benzoyl peroxide, Contains lauroyl peroxide and azobis-isobutyronitrile for the purpose Penetration of the mixture into the wood treated, b) the treated heat is heated to a temperature at least sufficient to decompose the polymariation initiator, as a result of which the reactive solvent polymerizes and the pentachlorophenol becomes insoluble in the polymer and is thus immobilized in the wood and c) removing the liquid carrier from the treated wood. 18 · - Method according to claim 17, characterized in that the Lay the wood with the impregnation coating at a minimum temperature Room temperature is treated to a temperature which is untar that the temperature of the polymerization initiator is sufficient for decomposition 19. Method according to claims 17 and 18, characterized in that the impregnation agent is a colourant from the group of methanol and other polymerizable monomers for the easier Dissolve the pentachlorophenols in the reactive LBaungamlttel reveals. · 20 - A method according to Anapruch 17 bia 19, characterized in that is is' ■ liquid carrier from the treated wood removed by evaporation. 21 · - Wood treatment preparation for impregnating Holt, comprehensive • in tmprägniarungaayatam aua a) Pentachlorophenol in ainar amount of wood treatment, TOIlIIfOTTI BATH ORIGINAL b) a reactive solvent from the group of styrene, Vinyl acetate, acrylonitrile, butyl acrylate, methacrylonitrile, methyl acrylate and mixtures of the same, c) a liquid carrier from the group of butane and pentane, in which the reactive solvent is soluble and the pentachlorophenol is practically insoluble, in an amount at least sufficient to dissolve the reactive solvent and d) a polymerization initiator from the group of benzoyl peroxide, Lauroyl peroxide and azobis-isobutyronitrile " 22 · - preparation according to claim 21, characterized in that the impregnation mixture is a cosolvent from the group of methanol, toluene, benzene, nitrobenzene, di- and trichlorobenzenes, alkylbenzenes, hydroxybenzenes, xylene, ethyl ether, isopropyl ether _; Vinyl ether, dibutyl ether, dibutyl ketone, diieobutyl ketone, methyl isobutyl ketone, benzonitrile, decalin, butyraldehyde, ieobutyraldehyde and polymerizable monomers that act as reactive solvents and support the dissolution of the pentachlorophenols in the reactive solvent. 23.- preparation according to claim 21 and 22, characterized in that that the impregnation mixture is the reactive solvent in an amount sufficient to solubilize the effective amount of wood treated contains pentachlorophenol. The patent attorney: 709838/0779