EP0282380B1 - Compositions for the treatment of wood and processes for the treatment of wood - Google Patents

Compositions for the treatment of wood and processes for the treatment of wood Download PDF

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Publication number
EP0282380B1
EP0282380B1 EP19880400352 EP88400352A EP0282380B1 EP 0282380 B1 EP0282380 B1 EP 0282380B1 EP 19880400352 EP19880400352 EP 19880400352 EP 88400352 A EP88400352 A EP 88400352A EP 0282380 B1 EP0282380 B1 EP 0282380B1
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EP
European Patent Office
Prior art keywords
wood
lanthanide
process according
composition
treatment
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EP19880400352
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German (de)
French (fr)
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EP0282380A1 (en
Inventor
Peter S. Gradeff
John F. Davison
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Rhodia Chimie SAS
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Rhone Poulenc Chimie SA
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Priority claimed from US07/017,159 external-priority patent/US4743473A/en
Priority claimed from US07/121,616 external-priority patent/US4842898A/en
Priority claimed from US07/121,623 external-priority patent/US4889771A/en
Application filed by Rhone Poulenc Chimie SA filed Critical Rhone Poulenc Chimie SA
Priority to AT88400352T priority Critical patent/ATE68742T1/en
Publication of EP0282380A1 publication Critical patent/EP0282380A1/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
    • B27K3/16—Inorganic impregnating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
    • B27K3/34—Organic impregnating agents
    • B27K3/36—Aliphatic compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
    • B27K3/34—Organic impregnating agents
    • B27K3/38—Aromatic compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
    • B27K3/02—Processes; Apparatus
    • B27K3/08—Impregnating by pressure, e.g. vacuum impregnation

Definitions

  • the present invention relates to methods of treating wood with a composition comprising at least one lanthanide derivative in aqueous solution.
  • organic preservatives are that they exude wood and can then be leached from the surface or evaporated. In order to compensate for the losses of said protective agents, high initial retentions are required. In tropical areas and in regions with high rainfall, the use of organic protective agents has proven uneconomical. Another disadvantage of some organic protective agents is that they can cause burns. In addition, organic agents such as creosote cannot be painted and have an unsightly appearance. In addition, said agents often have toxic side effects.
  • Aqueous protective agents are those which contain chemical protective agents in the form of aqueous solutions. These agents react inside the wood to form compounds whose solubility can be increased by adjusting the pH. When chemical changes occur inside the wood leading to compounds with very low solubility, these compounds are said to be resistant to leaching. Those which form soluble compounds are said to be “leachable”.
  • ACC acid copper chromate solution
  • CCA arsenate and copper chormate solution
  • ACA cuprous ammonium arsenate solution
  • Leachable aqueous protective agents include mixtures of zinc chloride and chromate, phenol, arsenate and chromium fluoride and boron compounds. Leachable aqueous protective agents can only be used for the treatment of wood used indoors or which is not exposed to severe leaching conditions.
  • aqueous protective agents has many advantages: cleanliness, possibility of painting treated wood, absence of odor and, when applied correctly, more durable protection of the wood.
  • US-A-2565175 to HAGER describes a wood treatment process using specific protective agents in combination with specific methods and conditions of penetration and distribution of these protective agents inside the wood.
  • One of the protective agents is CCA, to which ammonia is added to make the treatment solution alkaline. The addition of ammonia prevents the rapid fixation of the protective agent in the wood.
  • the protective agent is introduced into the wood and it is ensured that it does not dry during a period during which there is no fixation of the protective agent which diffuses then through the cell walls. Then we dry the wood.
  • US Pat. No. 4,325,993 to SCHRODER describes a process for protecting wood against attack by living organisms, for example fungi and insects.
  • the process can include one or two steps.
  • there is a fungicidal stage which consists in introducing a copper solution into the wood and an insecticidal stage which consists in introducing a chromium-arsenic solution.
  • Lanthanide derivatives are used for the manufacture of glass, ceramics, paints, plastics and rubber.
  • the compositions based on lanthanide compounds are known to possess bactericidal effects, for example: water-soluble salts which comprise a lanthanide cation and a carboxylate, organosulfate or organosulfonate anion having surface-active properties (cf. EP-A-0037224 and EP-A-0018019); compositions comprising cerium nitrate and silver sulfadiazine (BOECKX et al., BURNS VOL.
  • Cerium derivatives are also used as additives in plastics for food packaging.
  • One of the objectives of the present invention is to provide a new safe process for the treatment of wood with water-soluble compositions.
  • Another objective of the invention is to achieve a permanent bond of the lanthanide ions with the fibers of the wood.
  • Another object of the present invention is to delay the combustion and prevent degradation of the wood due to bacteria, insects, fungi and weather conditions.
  • the present invention meets the aforementioned objectives as well as others set out later in the description.
  • the subject of the present invention is a method of treating wood by impregnation using a composition comprising an aqueous solution of one or more lanthanide derivatives or of one or more derivatives of different lanthanides, the simultaneous use of one or more derivatives of cerium and CCA being excluded from the scope of the present invention.
  • the wood is impregnated by one or a combination of several known techniques, chosen so that the desired degree of penetration is obtained according to the intended use and a permanent bond of the lanthanide ions with the fibers of the wood is achieved.
  • composition comprising wood or wood derivatives and lanthanides or lanthanide derivatives.
  • the lanthanide or the lanthanide derivative expressed as lanthanide oxide, represent between approximately 0.10% and approximately 5.0% and, preferably, between approximately 0.10% and approximately 2.0% by weight of the composition.
  • This composition resists degradation which occurs on wood, free of lanthanides, exposed to wood destroying organisms such as bacteria, insects and fungi as well as environmental pollution.
  • the wood is treated with an aqueous solution comprising one or more lanthanide derivatives.
  • the wood protection treatment can be applied to any form or type of wood: felling wood, construction wood, stilts, cable-bearing posts, fence posts, plywood, joists and floors, wood for residential construction or commercial, shipbuilding wood, lumber, fibers for laminated materials, pulp, cooling towers, wood for storing crops and transporting food.
  • the term "wood”, as used herein, is not limited to the above list.
  • the lanthanide derivatives which are suitable are the lanthanides lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium or their mixtures.
  • the preferred lanthanides are cerium, lanthanum, praseodymium and neodymium. Cerium can be trivalent or tetravalent.
  • the lanthanide cation can be linked to an inorganic anion such as nitrate, chloride, sulfate, perchlorate, phosphate or phosphonate.
  • the lanthanide cation can also be linked to an organic ligand, such as low carbon condensation alkyl carboxylate, for example acetate, propionate, acrylate, methacrylate, gluconate, lactate, alkyl sulfonate or alkyl phosphonate. Derivatives with both organic and inorganic ligands are also suitable for the present invention.
  • Lanthanide derivatives can be used alone or in admixture with other wood treatment agents, such as flame retardants, coloring agents, anti-cracking agents, anti-static agents, dimensional stabilizers, film-forming agents, wood softening agents and other biocidal agents, such as fungicides, bactericides, herbicides, insecticides, algicides.
  • other wood treatment agents such as flame retardants, coloring agents, anti-cracking agents, anti-static agents, dimensional stabilizers, film-forming agents, wood softening agents and other biocidal agents, such as fungicides, bactericides, herbicides, insecticides, algicides.
  • the lanthanide derivatives must be soluble in water, preferably in an amount of at least about 0.1% by weight.
  • concentrations lower than 0.1% by weight is not economical. Concentrations between about 0.1 and about 10% are preferred although larger concentrations can be used. The concentrations chosen between approximately 0.5 and approximately 2.5% are particularly preferred.
  • the interaction between the lanthanide ion and the wood according to the process of the invention is a crosslinking of the cellulose fibers with the lanthanide ion.
  • the lanthanide ion is also believed to bind with other wood compounds, such as lignin and rosin, which provide active sites for chemical bonds.
  • the bond could involve one or more valences of the lanthanide element.
  • Crosslinking occurs in a range of relatively neutral pHs or acidic pHs (less than about 7). The interaction is faster during treatment under hydrostatic pressure or under vacuum and slower during surface treatment.
  • We apply the compositions so that the lanthanide cation penetrates into the wood fibers and reacts with the hydroxy sites or other active sites in the wood.
  • the time required to achieve a sufficient number of permanent bonds between the lanthanide and the wood depends on several factors, for example, the type of treatment, the type of wood to be treated as well as the conditions in which the material is found before treatment.
  • the lanthanide derivatives can be applied to wood according to any known method, in particular those described in the above-mentioned "Book of Standards”.
  • wood conditioning methods comprising preliminary steps intended to increase the penetration of the lanthanide compositions into the wood. Mention may be made of the stages of drying in air, in an oven, under vacuum, in steam or a combination thereof.
  • the composition can be applied comprising an aqueous solution of at least one lanthanide derivative according to a surface treatment, for example, immersion, spraying or brush application.
  • a surface treatment for example, immersion, spraying or brush application.
  • the treatment can be single or repeated in combination with other agents or alternately with different concentrations of the treating solutions depending on the degree of penetration sought.
  • the treatment can be carried out around room temperature or at higher temperatures.
  • the composition comprising an aqueous solution of at least one lanthanide derivative in a vacuum treatment which can be broken down into two stages. Initially, the wood is subjected to a vacuum treatment, then the treatment solution is introduced without reintroduction of air. It is obvious that the parameters of this process can vary within wide limits. Pre-conditioned wood requires less time and vacuum than wet wood. The duration and the vacuum depend on the size or shape of the material to be treated and the desired depth of penetration. The same is true for temperature.
  • the vacuum stage has for purpose of emptying the wood cells of the humidity and the air which they contain so that the lanthanide-based treatment solution can penetrate with less resistance in the empty cell. The effect is similar to that of treating wood under pressure. The same is true of the results.
  • composition can also be applied comprising an aqueous solution of at least one lanthanide derivative according to a pressure process which can be used to treat wood which has been conditioned or not.
  • the process involves applying hydrostatic pressure to the wood immersed in the lanthanide-based treatment solution.
  • the contact time can vary widely depending on the condition, type and thickness of the wood.
  • the contact time varies between about 30 minutes and about 10 hours. Of course, longer durations can be used.
  • the contact time can be reduced when the pressure is increased.
  • a contact time of between about 3 and about 6 hours is preferred. It has been demonstrated that most of the bonds are formed during the immersion of the wood in the lanthanide solution and that the crosslinking reaction can continue for several days after treatment.
  • the pressure must be higher than atmospheric pressure. At atmospheric pressure, there is no significant permanent bond formation. Although there is some impregnation of the wood, the deposited derivative can be almost completely leached from the wood.
  • the pressure is chosen between approximately 10 psi (6.895 ⁇ 104 Pa) and approximately 300 psi (2.0684 ⁇ 106 Pa) and even more preferably between approximately 50 psi (3.4473 ⁇ 105 Pa) and approximately 280 psi ( 1.9305 ⁇ 106 Pa).
  • the wood is immersed in a closed reactor containing a composition of the lanthanide derivative, then hydrostatic pressure is applied.
  • the pressure can be applied, for example, by compression of the bath using mechanical means (isostatic pump).
  • the pressure can also be maintained using one or more inert gases, for example nitrogen.
  • the treatment temperature should not exceed approximately 95 ° C.
  • the temperature chosen is room temperature, namely between approximately 20 and approximately 30 ° C.
  • a temperature chosen between around 40 and 60 ° C. is preferred to facilitate penetration and bonding between the lanthanide cation and the wood fibers.
  • the aqueous solution is removed.
  • the amount of lanthanide derivatives can be adjusted and the resulting solution can be used for the treatment of another load of wood.
  • the treated wood is simply left to dry.
  • Treated wood is resistant to degradation caused by bacteria, insects, fungi and weather conditions.
  • the treatment makes it possible to delay the combustion of the wood.
  • One of the main advantages of using lanthanides is their relative safety, which is important during the implementation of the process, the subsequent handling or leaching or when there is sludge formation.
  • the wood is brought into contact with a treating solution and penetration of the latter occurs.
  • the term "penetration" is not sufficient to describe and explain the unexpected and superior results of the wood treated with the aqueous lanthanide compositions.
  • the present invention provides a permanent attachment of the elements to the wood.
  • permanent fixation also called bond or crosslinking in the present application, is meant that the lanthanide ion is fixed to the fibers so that it is no longer possible for it to be leached by water.
  • the wood treated with the lanthanides under pressure has a greater amount of bound lanthanide ions after aging than when it was tested just after the treatment.
  • the treated wood sample is washed with running water for 12 hours.
  • the washed wood is then dried, and the percentage of ash measured is determined after combustion of the sample and calcination of the residue at 1000 ° C.
  • the percentage of "ash" before treatment is subtracted from the percentage of "ash" of the treated wood in order to determine the amount of lanthanide permanently bound.
  • test results show that there is more lanthanide derivative permanently attached to wood when pressure is applied rather than when atmospheric pressure is applied.
  • the percentage of ash increases. This indicates that the crosslinking process continues over several days. Table II illustrates the benefits of aging.
  • Southern yellow pine wood is treated with lanthanide derivatives by immersion, spraying or brushing with a composition comprising an aqueous solution of a lanthanide derivative.
  • the treated wood is left to dry and age for several days.
  • the samples are leached under running water as described in Example 1, then reduced to ashes.
  • the results show that a certain quantity of lanthanide ions is permanently linked (cf. example 1, tests 5, 13, 16, 19, 22, 25).
  • leaching occurs after the aging period of several days or months after treatment, greater amounts of bound lanthanide ions are found.
  • Standardized samples having undergone no preconditioning, are placed in a two-necked reactor, equipped with a dropping funnel containing a 2% aqueous solution of cerium nitrate.
  • a reduced pressure is established (about 2.66.102 Pa) which is maintained for 10 hours.
  • the reactor is filled with the cerium nitrate solution and the samples are kept immersed for about 4 hours.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)

Description

La présente invention se rapporte à des procédés de traitement du bois avec une composition comprenant au moins un dérivé de lanthanide en solution aqueuse.The present invention relates to methods of treating wood with a composition comprising at least one lanthanide derivative in aqueous solution.

Il est connu que, dans l'état de la technique, les agents de protection du bois sont sous forme de formulations soit organiques soit aqueuses. Il existe deux classes principales d'agents de protection organiques, à savoir:

1. ―
la créosote de houille et les solutions de créosote avec des goudrons de houille ou des huiles de pétrole et
2. ―
les solutions d'agents de protection chimiques tels que le pentachlorophénol dissous dans un véhiculeur organique approprié.

It is known that, in the state of the art, wood preservatives are in the form of either organic or aqueous formulations. There are two main classes of organic protective agents, namely:
1. -
coal creosote and creosote solutions with coal tars or petroleum oils and
2. -
solutions of chemical protective agents such as pentachlorophenol dissolved in a suitable organic carrier.

L'un des inconvénients des agents de protection organiques est qu'ils exsudent du bois et qu'ils peuvent ensuite être lixiviés de la surface ou évaporés. Afin de compenser les pertes desdits agents de protection, il faut des rétentions initiales élevées. Dans les zones tropicales et dans les régions à fortes précipitations, l'usage des agents de protection organiques s'est révelé peu économique. Un autre inconvénient de certains agents de protection organiques est qu'ils peuvent provoquer des brûlures. En outre, les agents organiques tels que la créosote ne peuvent pas être peints et ont un aspect inesthétique. De plus, lesdits agents présentent souvent des effets secondaires toxiques.One of the disadvantages of organic preservatives is that they exude wood and can then be leached from the surface or evaporated. In order to compensate for the losses of said protective agents, high initial retentions are required. In tropical areas and in regions with high rainfall, the use of organic protective agents has proven uneconomical. Another disadvantage of some organic protective agents is that they can cause burns. In addition, organic agents such as creosote cannot be painted and have an unsightly appearance. In addition, said agents often have toxic side effects.

Les agents de protection aqueux sont ceux qui contiennent les agents de protection chimiques sous forme de solutions aqueuses. Ces agents réagissent à l'intérieur du bois pour former des composés dont la solubilité peut être accrue par ajustement du pH. Lorsqu'il se produit à l'intérieur du bois des modifications chimiques conduisant à des composés de très faible solubilité, ces composés sont dits résistants à la lixiviation. Ceux qui forment des composés solubles sont dits "lixiviables".Aqueous protective agents are those which contain chemical protective agents in the form of aqueous solutions. These agents react inside the wood to form compounds whose solubility can be increased by adjusting the pH. When chemical changes occur inside the wood leading to compounds with very low solubility, these compounds are said to be resistant to leaching. Those which form soluble compounds are said to be "leachable".

Comme agents de protection aqueux résistant à la lixiviation et commercialisés, on peut citer: la solution de chromate de cuivre acide (ACC), la solution d'arséniate et de chormate de cuivre (CCA) et la solution d'arséniate cuivreux ammoniacal (ACA). On utilise couramment les solutions CCA. Elles forment dans le bois des composés qui sont toxiques à la fois vis-à-vis des champignons et des insectes.As aqueous protective agents which are resistant to leaching and which are marketed, there may be mentioned: acid copper chromate solution (ACC), the arsenate and copper chormate solution (CCA) and the cuprous ammonium arsenate solution (ACA). CCA solutions are commonly used. They form compounds in wood that are toxic to both fungi and insects.

Les agents de protection aqueux lixiviables comprennent les mélanges de chlorure et de chromate de zinc, de phénol, arséniate et fluorure de chrome et des composés du bore. Les agents de protection aqueux lixiviables ne peuvent être employés que pour le traitement des bois utilisés à l'intérieur ou qui ne sont pas exposés à des conditions de lixiviation sévères.Leachable aqueous protective agents include mixtures of zinc chloride and chromate, phenol, arsenate and chromium fluoride and boron compounds. Leachable aqueous protective agents can only be used for the treatment of wood used indoors or which is not exposed to severe leaching conditions.

L'utilisation d'agents de protection aqueux présente de nombreux avantages: propreté, possibilité de peindre le bois traité, absence d'odeur et, lorsqu'ils sont appliqués correctement, protection plus durable du bois.The use of aqueous protective agents has many advantages: cleanliness, possibility of painting treated wood, absence of odor and, when applied correctly, more durable protection of the wood.

L'ouvrage "Book of Standards" (1986) de l'Association "American Wood Preserver's Association" définit et décrit aux pages 1978 et 1979 les techniques, bien connues, d'application des compositions traitantes pour le bois. Parmi les techniques courantes, on peut citer le traitement sous pression, le traitement sous vide et les traitements de surface tels que immersion, pulvérisation ou application à la brosse.The book "Book of Standards" (1986) of the Association "American Wood Preserver's Association" defines and describes on pages 1978 and 1979 the techniques, well known, of application of the treating compositions for wood. Common techniques include pressure treatment, vacuum treatment and surface treatments such as immersion, spraying or brushing.

Ces méthodes conduisent au résultat désiré en appliquant sur le bois des compositions ayant des propriétés de protection du bois. La description des méthodes de traitement du bois décrites dans ces pages et tout au long du livre "Book of Standards" est incorporée par référence dans la présente demande.These methods lead to the desired result by applying to the wood compositions having protective properties for the wood. The description of the wood treatment methods described in these pages and throughout the book "Book of Standards" is incorporated by reference into the present application.

Les caractéristiques essentielles du traitement sous pression sont:

1. ―
le bois est entouré d'une solution de l'agent de protection dans un réacteur fermé;
2. ―
une pression hydrostatique est appliquée par des moyens mécaniques pour faire pénétrer de force la solution dans les fibres du bois remplaçant l'air ou l'eau présents dans le bois ou pénétrant dans tous les espaces vides. Il est habituel d'abaisser la pression à 26 mm de mercure pour éliminer l'air contenu dans les cellules du bois. Lorsqu'on utilise une solution de CCA pour imprégner le bois, le CCA réagit à l'intérieur du bois en réduisant les sucres pour former un mélange de sels insolubles.
The essential characteristics of pressure treatment are:
1. -
the wood is surrounded by a solution of the protection agent in a closed reactor;
2. -
hydrostatic pressure is applied by mechanical means to force the solution into the wood fibers replacing the air or water present in the wood or entering all the empty spaces. It is usual to lower the pressure to 26 mm of mercury to eliminate the air contained in the wood cells. When a CCA solution is used to impregnate the wood, the CCA reacts inside the wood by reducing the sugars to form a mixture of insoluble salts.

Le brevet US-A-2565175 de HAGER décrit un procédé de traitement du bois utilisant des agents de protection spécifiques en combinaison avec des méthodes spécifiques et des conditions de pénétration et de répartition de ces agents de protection à l'intérieur du bois. L'un des agents de protection est le CCA, auquel on ajoute de l'ammoniaque pour rendre alcaline la solution traitante. L'addition de l'ammoniaque empêche la fixation rapide de l'agent de protection dans le bois. Selon la méthode décrite par HAGER, on introduit l'agent de protection dans le bois et l'on veille à ce qu'il ne sèche pas durant une période pendant laquelle il ne se produit pas de fixation de l'agent de protection qui diffuse alors à travers les parois cellulaires. Ensuite, on sèche le bois.US-A-2565175 to HAGER describes a wood treatment process using specific protective agents in combination with specific methods and conditions of penetration and distribution of these protective agents inside the wood. One of the protective agents is CCA, to which ammonia is added to make the treatment solution alkaline. The addition of ammonia prevents the rapid fixation of the protective agent in the wood. According to the method described by HAGER, the protective agent is introduced into the wood and it is ensured that it does not dry during a period during which there is no fixation of the protective agent which diffuses then through the cell walls. Then we dry the wood.

Le brevet US-A-4325993 de SCHRODER décrit un procédé pour protéger le bois contre l'attaque des organismes vivants, par exemple champignons et insectes. Le procédé peut comprendre une ou deux étapes. Dans le procédé à deux étapes, il y a une étape fongicide qui consiste à introduire une solution de cuivre dans le bois et une étape insecticide qui consiste à y introduire une solution chrome-arsenic.US Pat. No. 4,325,993 to SCHRODER describes a process for protecting wood against attack by living organisms, for example fungi and insects. The process can include one or two steps. In the two-stage process, there is a fungicidal stage which consists in introducing a copper solution into the wood and an insecticidal stage which consists in introducing a chromium-arsenic solution.

A propos des méthodes de traitement du bois, on citera encore l'ouvrage "Wood Handbook: Wood as an engineering material", Agriculture Handbook n° 72, août 1974, chapitre 18, pages 18-1 à 18-24.Regarding wood treatment methods, there is also the book "Wood Handbook: Wood as an engineering material", Agriculture Handbook n ° 72, August 1974, chapter 18, pages 18-1 to 18-24.

L'un des inconvénients d'utiliser le CCA est qu'il ne se fixe pas complètement dans le bois. Il peut se former dans la solution mise en oeuvre de la boue provenant du bois, de la corrosion ou des impuretés contenues dans les produits chimiques utilisés pour préparer la solution. Cette boue est la cause d'un dépôt solide à la surface du bois. Ces dépôts contiennent des pourcentages variables d'arsenic et ainsi se posent des problèmes d'environnement. Ceci a été pris en considération par les normes récentes concernant le traitement du bois (AWPA 1982) (cf HARTFORD, W. "The Practical Chemistry of CCA in Service", American Wood Preserver's Association Annual Meeting, 28, 29 et 30 avril 1986, pages 1-16).One of the drawbacks of using the CCA is that it does not settle completely in the wood. It can form in the solution used for mud from wood, corrosion or impurities contained in the chemicals used to prepare the solution. This mud is the cause of a solid deposit on the surface of the wood. These deposits contain varying percentages of arsenic and thus pose environmental problems. This has been taken into account by recent standards for wood treatment (AWPA 1982) (see HARTFORD, W. "The Practical Chemistry of CCA in Service", American Wood Preserver's Association Annual Meeting, April 28, 29 and 30, 1986, pages 1-16).

Les dérivés du lanthanide sont utilisés pour la fabrication du verre, des céramiques, des peintures, des matières plastiques et du caoutchouc. Les compositions à base de composés de lanthanide sont connues pour posséder des effets bactéricides, par exemple: des sels hydrosolubles qui comprennent un cation lanthanide et un anion carboxylate, organosulfate ou organosulfonate possédant des propriétés tensio-actives (cf. EP-A-0037224 et EP-A-0018019); des compositions comprenant du nitrate de cérium et de la sulfadiazine d'argent (BOECKX et al., BURNS VOL. Il N° 5 (1985) pages 337-342; Monafo, 3rd International Congress on Pharmacological Treatment of Burns, Milan, Italy, May 12-15, 1980, Panmainerva Med., vol 25, n° 3 (1983) pages 151-154; Bowser et al., J. Trauma, vol 21, n° 7 (1981) pages 558-563; Monafo et al., Arch. Surg. vol. 113, n° 4 (1978) pages 397-401; Monafo et al. Surgery (Saint Louis) vol 80, n° 4 (1976) pages 465-473, et les compositions comprenant de l'argent activié électriquement et du stéarate de cérium (Colmano et al., 23rd Annual Meeting of the Biophysical Society (New-York), Atlanta GA., Feb. 26-28, 1979, Biophys. J. vol 25, n° 2, part 2 (1979) page 217A).Lanthanide derivatives are used for the manufacture of glass, ceramics, paints, plastics and rubber. The compositions based on lanthanide compounds are known to possess bactericidal effects, for example: water-soluble salts which comprise a lanthanide cation and a carboxylate, organosulfate or organosulfonate anion having surface-active properties (cf. EP-A-0037224 and EP-A-0018019); compositions comprising cerium nitrate and silver sulfadiazine (BOECKX et al., BURNS VOL. Il N ° 5 (1985) pages 337-342; Monafo, 3rd International Congress on Pharmacological Treatment of Burns , Milan, Italy, May 12-15, 1980, Panmainerva Med. , Vol 25, n ° 3 (1983) pages 151-154; Bowser et al., J. Trauma , vol 21, n ° 7 (1981) pages 558-563; Monafo and al., Arch Surg. vol. 113, no. 4 (1978) pages 397-401; Monafo et al. Surgery (Saint Louis) vol 80, no. 4 (1976) pages 465-473, and the compositions comprising electrically activated silver and cerium stearate (Colmano et al., 23rd Annual Meeting of the Biophysical Society (New-York), Atlanta GA. , Feb. 26-28, 1979, Biophys. J. vol 25, no. 2, part 2 (1979) page 217A).

Les dérivés du cérium sont utilisés encore:

  • ― en solution aqueuse comme catalyseur pour réaliser une réaction de polymérisation-greffage entre des monomères vinyliques et une substance cellulosique (cf. Chemical Abstracts, vol 80, 1974, 37749 d),
  • ― et comme agent de stabilisation pour des compositions aqueuses de protection du bois à base de CCA (cf. EP-A-0226292).
Cerium derivatives are still used:
  • In aqueous solution as a catalyst for carrying out a polymerization-grafting reaction between vinyl monomers and a cellulosic substance (cf. Chemical Abstracts, vol 80, 1974, 37749 d),
  • - And as a stabilizing agent for aqueous wood protection compositions based on CCA (cf. EP-A-0226292).

Les dérivés du cérium sont utilisés également comme additifs dans les matières plastiques pour emballages alimentaires.Cerium derivatives are also used as additives in plastics for food packaging.

L'un des objectifs de la présente invention est de fournir un nouveau procédé sans danger pour le traitement des bois avec des compositions hydrosolubles.One of the objectives of the present invention is to provide a new safe process for the treatment of wood with water-soluble compositions.

Un autre objectif de l'invention est de réaliser une liaison permanente des ions lanthanide avec les fibres du bois.Another objective of the invention is to achieve a permanent bond of the lanthanide ions with the fibers of the wood.

Un autre objectif de la présente invention est de retarder la combustion et d'empêcher la dégradation du bois due aux bactéries, aux insectes, aux champignons et aux conditions atmosphériques.Another object of the present invention is to delay the combustion and prevent degradation of the wood due to bacteria, insects, fungi and weather conditions.

La présente invention répond aux objectifs précités ainsi qu'à d'autres exposés plus loin dans la description.The present invention meets the aforementioned objectives as well as others set out later in the description.

La présente invention a pour objet un procédé de traitement du bois par imprégnation à l'aide d'une composition comprenant une solution aqueuse d'un ou plusieurs dérivés de lanthanide ou d'un ou plusieurs dérivés de différents lanthanides, l'emploi simultané d'un ou plusieurs dérivés du cérium et de CCA étant exclu du domaine de la présente invention. On imprègne le bois par une ou une combinaison de plusieurs techniques connues, choisies de telle sorte que l'on obtienne le degré de pénétration souhaité selon l'utilisation envisagée et réalise une liaison permanente des ions lanthanides avec les fibres du bois. C'est ainsi que l'on inclut les traitements sous pression, sous vide, les traitements de surface, tels que immersion, pulvérisation et application à la brosse, les traitements dits "en cellule pleine", comprenant à la fois un traitement préliminaire sous vide et une imprégnation sous pression conduisant à un remplissage plus ou moins complet des cavités cellulaires, ainsi que tous les autres modes de traitement connus.The subject of the present invention is a method of treating wood by impregnation using a composition comprising an aqueous solution of one or more lanthanide derivatives or of one or more derivatives of different lanthanides, the simultaneous use of one or more derivatives of cerium and CCA being excluded from the scope of the present invention. The wood is impregnated by one or a combination of several known techniques, chosen so that the desired degree of penetration is obtained according to the intended use and a permanent bond of the lanthanide ions with the fibers of the wood is achieved. This includes pressure treatments, vacuum treatments, surface treatments such as immersion, spraying and brushing, so-called "full cell" treatments, including both a preliminary treatment under vacuum and impregnation under pressure leading to a more or less complete filling of the cell cavities, as well as all the other known treatment methods.

Une première variante du procédé de l'invention réside dans un traitement du bois qui consiste:

  • ― à mettre en contact le bois avec une composition comprenant une solution aqueuse d'au moins un dérivé de lanthanide pour imprégner le bois avec lesdits dérivés,
  • ― à laisser sécher à l'air le complexe bois-solution,
  • ― à faire vieillir le complexe bois-solution pendant une durée suffisante pour obtenir une liaison entre l'élément lanthanide et le bois.
A first variant of the process of the invention lies in a treatment of wood which consists:
  • - bringing the wood into contact with a composition comprising an aqueous solution of at least one lanthanide derivative to impregnate the wood with said derivatives,
  • - allow the wood-solution complex to air dry,
  • - aging the wood-solution complex for a sufficient time to obtain a bond between the lanthanide element and the wood.

Une autre variante du procédé de l'invention consiste:

  • ― à soumettre le bois à un traitement sous vide,
  • ― à introduire une composition comprenant une solution aqueuse d'au moins un dérivé de lanthanide et à mettre en contact le bois et ladite composition pendant une durée suffisante pour obtenir une liaison entre l'élément lanthanide et le bois.
Another variant of the process of the invention consists:
  • - subject the wood to vacuum treatment,
  • - Introducing a composition comprising an aqueous solution of at least one lanthanide derivative and bringing the wood and said composition into contact for a sufficient time to obtain a bond between the lanthanide element and the wood.

Une autre variante du procédé de l'invention réside dans un procédé de traitement du bois sous pression, caractérisé par le fait qu'il consiste:

  • ― à immerger le bois dans une composition comprenant une solution aqueuse d'au moins un dérivé de lanthanide,
  • ― à maintenir une pression élevée pendant une durée suffisante pour obtenir une liaison entre l'élément lanthanide et le bois.
Another variant of the process of the invention resides in a process for treating wood under pressure, characterized in that it consists:
  • - immersing the wood in a composition comprising an aqueous solution of at least one lanthanide derivative,
  • - to maintain a high pressure for a sufficient time to obtain a connection between the lanthanide element and the wood.

Dans toutes les variantes des procédés de l'invention, on est conduit à une composition comprenant le bois ou les dérivés du bois et les lanthanides ou les dérivés de lanthanides.In all the variants of the processes of the invention, a composition is obtained comprising wood or wood derivatives and lanthanides or lanthanide derivatives.

Dans ladite composition, le lanthanide ou le dérivé de lanthanide, exprimé en oxyde de lanthanide, représentent entre environ 0,10% et environ 5,0% et, de préférence, entre environ 0,10% et environ 2,0% du poids de la composition.In said composition, the lanthanide or the lanthanide derivative, expressed as lanthanide oxide, represent between approximately 0.10% and approximately 5.0% and, preferably, between approximately 0.10% and approximately 2.0% by weight of the composition.

Cette composition résiste à la dégradation qui se produit sur les bois, exempts de lanthanides, exposés aux organismes destructeurs du bois tels que bactéries, insectes et champignons aussi bien qu'à une pollution de l'environnement.This composition resists degradation which occurs on wood, free of lanthanides, exposed to wood destroying organisms such as bacteria, insects and fungi as well as environmental pollution.

Selon les procédés de la présente invention, on traite le bois avec une solution aqueuse comprenant un ou plusieurs dérivés de lanthanide. On peut appliquer le traitement de protection du bois sur n'importe quelle forme ou type de bois: bois d'abattage, bois de construction, pilotis, poteaux porteurs de câbles, poteaux de clôtures, contreplaqués, lambourdes et planchers, bois pour constructions résidentielles ou commerciales, bois de construction navale, bois de charpente, fibres pour matériaux laminés, pâte à papier, tours de refroidissement, bois pour le stockage des récoltes et le transport des denrées alimentaires. Le terme "bois", tel qu'utilisé ici, n'est pas limité à la liste ci-dessus.According to the methods of the present invention, the wood is treated with an aqueous solution comprising one or more lanthanide derivatives. The wood protection treatment can be applied to any form or type of wood: felling wood, construction wood, stilts, cable-bearing posts, fence posts, plywood, joists and floors, wood for residential construction or commercial, shipbuilding wood, lumber, fibers for laminated materials, pulp, cooling towers, wood for storing crops and transporting food. The term "wood", as used herein, is not limited to the above list.

Les dérivés de lanthanide qui conviennent sont les lanthanides lanthane, cérium, praséodyme, néodyme, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutétium ou leurs mélanges. Les lanthanides préférés sont le cérium, le lanthane, le praséodyme et le néodyme. Le cérium peut être à l'état trivalent ou tétravalent.The lanthanide derivatives which are suitable are the lanthanides lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium or their mixtures. The preferred lanthanides are cerium, lanthanum, praseodymium and neodymium. Cerium can be trivalent or tetravalent.

Le cation lanthanide peut être lié à un anion inorganique tel que nitrate, chlorure, sulfate, perchlorate, phosphate ou phosphonate. Le cation lanthanide peut être lié aussi à un ligand organique, tel que carboxylate d'alkyle à faible condensation en carbone, par exemple acétate, propionate, acrylate, méthacrylate, gluconate, lactate, sulfonate d'alkyle ou phosphonate d'alkyle. Les dérivés à ligands à la fois organique et inorganique conviennent aussi à la présente invention.The lanthanide cation can be linked to an inorganic anion such as nitrate, chloride, sulfate, perchlorate, phosphate or phosphonate. The lanthanide cation can also be linked to an organic ligand, such as low carbon condensation alkyl carboxylate, for example acetate, propionate, acrylate, methacrylate, gluconate, lactate, alkyl sulfonate or alkyl phosphonate. Derivatives with both organic and inorganic ligands are also suitable for the present invention.

Les dérivés de lanthanide peuvent être utilisés seuls ou en mélange avec d'autres agents de traitement du bois, tels que agents ignifugeants, agents colorants, agents anti-craquelures, agents anti-statiques, stabilisateurs dimensionnels, agents filmogènes, agents amollissants du bois et d'autres agents biocides, tels que fongicides, bactéricides, herbicides, insecticides, algicides.Lanthanide derivatives can be used alone or in admixture with other wood treatment agents, such as flame retardants, coloring agents, anti-cracking agents, anti-static agents, dimensional stabilizers, film-forming agents, wood softening agents and other biocidal agents, such as fungicides, bactericides, herbicides, insecticides, algicides.

Les dérivés de lanthanide doivent être solubles dans l'eau, préférentiellement en une quantité d'au moins environ 0,1% en poids. L'usage de concentrations inférieures à 0,1% en poids n'est pas économique. Les concentrations comprises entre environ 0,1 et environ 10% sont préférées bien que des concentrations plus grandes puissent être utilisées. Les concentrations choisies entre environ 0,5 et environ 2,5% sont particulièrement préférées.The lanthanide derivatives must be soluble in water, preferably in an amount of at least about 0.1% by weight. The use of concentrations lower than 0.1% by weight is not economical. Concentrations between about 0.1 and about 10% are preferred although larger concentrations can be used. The concentrations chosen between approximately 0.5 and approximately 2.5% are particularly preferred.

On pense que l'interaction entre l'ion lanthanide et le bois selon le procédé de l'invention est une réticulation des fibres de cellulose avec l'ion lanthanide. On pense également que l'ion lanthanide se lie avec d'autres composés du bois, tels que la lignine et la colophane qui offrent des sites actifs pour les liaisons chimiques. La liaison pourrait faire intervenir une ou plusieurs valences de l'élément lanthanide. La réticulation intervient dans une gamme de pH relativement neutres ou de pH acides (inférieurs à environ 7). L'interaction est plus rapide lors d'un traitement sous pression hydrostatique ou sous vide et plus lente lors d'un traitement de surface. On applique les compositions de sorte que le cation lanthanide pénètre dans les fibres de bois et réagisse avec les sites hydroxy ou d'autres sites actifs du bois.It is believed that the interaction between the lanthanide ion and the wood according to the process of the invention is a crosslinking of the cellulose fibers with the lanthanide ion. The lanthanide ion is also believed to bind with other wood compounds, such as lignin and rosin, which provide active sites for chemical bonds. The bond could involve one or more valences of the lanthanide element. Crosslinking occurs in a range of relatively neutral pHs or acidic pHs (less than about 7). The interaction is faster during treatment under hydrostatic pressure or under vacuum and slower during surface treatment. We apply the compositions so that the lanthanide cation penetrates into the wood fibers and reacts with the hydroxy sites or other active sites in the wood.

La durée nécessaire pour réaliser un nombre suffisant de liaisons permanentes entre le lanthanide et le bois dépend de plusieurs facteurs, par exemple, le type de traitement, le type de bois à traiter ainsi que les conditions dans lesquelles se trouve le matériau avant le traitement.The time required to achieve a sufficient number of permanent bonds between the lanthanide and the wood depends on several factors, for example, the type of treatment, the type of wood to be treated as well as the conditions in which the material is found before treatment.

Conformément à l'invention, on peut appliquer les dérivés de lanthanides sur le bois selon n'importe quelle méthode connue, en particulier celles décrites dans le "Book of Standards" précité.In accordance with the invention, the lanthanide derivatives can be applied to wood according to any known method, in particular those described in the above-mentioned "Book of Standards".

Font également partie de l'invention les procédés de conditionnement du bois comportant des étapes préliminaires destinées à augmenter la pénétration des compositions de lanthanide dans le bois. On peut citer les étapes de séchage à l'air, en étuve, sous vide, à la vapeur ou une combinaison de celles-ci.Also included in the invention are the wood conditioning methods comprising preliminary steps intended to increase the penetration of the lanthanide compositions into the wood. Mention may be made of the stages of drying in air, in an oven, under vacuum, in steam or a combination thereof.

On peut appliquer la composition comprenant une solution aqueuse d'au moins un dérivé de lanthanide selon un traitement de surface, par exemple, immersion, pulvérisation ou application à la brosse. Le traitement peut être unique ou répété en combinaison avec d'autres agents ou en alternance avec différentes concentrations des solutions traitantes selon le degré de pénétration recherché. On peut conduire le traitement aux environs de la température ambiante ou à des températures plus élevées.The composition can be applied comprising an aqueous solution of at least one lanthanide derivative according to a surface treatment, for example, immersion, spraying or brush application. The treatment can be single or repeated in combination with other agents or alternately with different concentrations of the treating solutions depending on the degree of penetration sought. The treatment can be carried out around room temperature or at higher temperatures.

Il est également possible de mettre en oeuvre la composition comprenant une solution aqueuse d'au moins un dérivé de lanthanide dans un traitement sous vide qui peut être décomposé en deux étapes. Dans un premier temps, on soumet le bois à un traitement sous vide, puis on introduit la solution traitante sans réintroduction d'air. Il est évident que les paramètres de ce procédé peuvent varier dans de larges limites. Le bois pré-conditionné nécessite moins de temps et de vide que le bois humide. La durée ainsi que le vide dépendent de la taille ou de la forme du matériau à traiter et de la profondeur de pénétration désirée. Il en est de même en ce qui concerne la température. L'étape sous vide a pour but de vider les cellules du bois de l'humidité et de l'air qu'elles contiennent de sorte que la solution traitante à base de lanthanide puisse pénétrer avec une résistance moindre dans la cellule vide. L'effet est similaire à celui du traitement du bois sous pression. Il en est de même des résultats.It is also possible to use the composition comprising an aqueous solution of at least one lanthanide derivative in a vacuum treatment which can be broken down into two stages. Initially, the wood is subjected to a vacuum treatment, then the treatment solution is introduced without reintroduction of air. It is obvious that the parameters of this process can vary within wide limits. Pre-conditioned wood requires less time and vacuum than wet wood. The duration and the vacuum depend on the size or shape of the material to be treated and the desired depth of penetration. The same is true for temperature. The vacuum stage has for purpose of emptying the wood cells of the humidity and the air which they contain so that the lanthanide-based treatment solution can penetrate with less resistance in the empty cell. The effect is similar to that of treating wood under pressure. The same is true of the results.

Bien que le traitement sous pression soit plus courant que le traitement sous vide, l'Association "American Wood Preserver's Association" a adopté le traitement sous vide comme méthode d'application normalisée des agents de protection du bois.Although pressure treatment is more common than vacuum treatment, the American Wood Preserver's Association has adopted vacuum treatment as the standard application method for wood preservatives.

On peut également appliquer la composition comprenant une solution aqueuse d'au moins un dérivé de lanthanide selon un procédé sous pression qui peut être utilisé pour traiter du bois préalablement conditionné ou pas. Le procédé consiste à appliquer une pression hydrostatique au bois immergé dans la solution traitante à base de lanthanide. Le temps de contact peut varier largement selon l'état, le type et l'épaisseur du bois.The composition can also be applied comprising an aqueous solution of at least one lanthanide derivative according to a pressure process which can be used to treat wood which has been conditioned or not. The process involves applying hydrostatic pressure to the wood immersed in the lanthanide-based treatment solution. The contact time can vary widely depending on the condition, type and thickness of the wood.

De préférence, le temps de contact varie entre environ 30 minutes et environ 10 heures. Bien sûr, des durées plus longues peuvent être utilisées. Le temps de contact peut être diminué lorsque l'on augmente la pression. Un temps de contact compris entre environ 3 et environ 6 heures est préféré. Il a été mis en évidence que la plupart des liaisons se forment durant l'immersion du bois dans la solution de lanthanide et que la réaction de réticulation peut se poursuivre pendant plusieurs jours après le traitement.Preferably, the contact time varies between about 30 minutes and about 10 hours. Of course, longer durations can be used. The contact time can be reduced when the pressure is increased. A contact time of between about 3 and about 6 hours is preferred. It has been demonstrated that most of the bonds are formed during the immersion of the wood in the lanthanide solution and that the crosslinking reaction can continue for several days after treatment.

La pression doit être supérieure à la pression atmosphérique. A la pression atmosphérique, il n'y a pas de formation de liaisons permanentes de façon significative. Bien qu'il y ait une certaine imprégnation du bois, le dérivé déposé peut être presque totalement lixivié du bois. De préférence, la pression est choisie entre environ 10 psi (6,895 · 10⁴ Pa) et environ 300 psi (2,0684 · 10⁶ Pa) et encore plus préférentiellement entre environ 50 psi (3,4473 · 10⁵ Pa) et environ 280 psi (1,9305 · 10⁶ Pa).The pressure must be higher than atmospheric pressure. At atmospheric pressure, there is no significant permanent bond formation. Although there is some impregnation of the wood, the deposited derivative can be almost completely leached from the wood. Preferably, the pressure is chosen between approximately 10 psi (6.895 · 10⁴ Pa) and approximately 300 psi (2.0684 · 10⁶ Pa) and even more preferably between approximately 50 psi (3.4473 · 10⁵ Pa) and approximately 280 psi ( 1.9305 · 10⁶ Pa).

Selon un mode de réalisation pratique de l'invention, le bois est immergé dans un réacteur fermé contenant une composition du dérivé de lanthanide, puis on applique une pression hydrostatique. La pression peut être appliquée, par exemple, par compression du bain à l'aide de moyens mécaniques (pompe isostatique). La pression peut être également maintenue en utilisant un ou plusieurs gaz inertes, par exemple l'azote.According to a practical embodiment of the invention, the wood is immersed in a closed reactor containing a composition of the lanthanide derivative, then hydrostatic pressure is applied. The pressure can be applied, for example, by compression of the bath using mechanical means (isostatic pump). The pressure can also be maintained using one or more inert gases, for example nitrogen.

La température du traitement ne doit pas excéder environ 95°C. De préférence, la température choisie est la température ambiante, à savoir entre environ 20 et environ 30°C. Pour certains traitements, une température choisie entre environ 40 et 60°C est préférée pour faciliter la pénétration et la liaison entre le cation lanthanide et les fibres de bois.The treatment temperature should not exceed approximately 95 ° C. Preferably, the temperature chosen is room temperature, namely between approximately 20 and approximately 30 ° C. For certain treatments, a temperature chosen between around 40 and 60 ° C. is preferred to facilitate penetration and bonding between the lanthanide cation and the wood fibers.

Après le traitement, la solution aqueuse est éliminée. La quantité de dérivés de lanthanide peut être ajustée et la solution résultante peut être utilisée pour le traitement d'une autre charge de bois. Le bois traité est laissé simplement à sécher. Le bois traité est résistant à la dégradation causée par les bactéries, les insectes, les champignons et les conditions atmosphériques. De plus, le traitement permet de retarder la combustion du bois. L'un des principaux avantages de l'utilisation des lanthanides est leur relative inocuité, ce qui est important durant la mise en oeuvre du procédé, la manipulation ou la lixiviation subséquente ou lorsqu'il y a formation de boues.After treatment, the aqueous solution is removed. The amount of lanthanide derivatives can be adjusted and the resulting solution can be used for the treatment of another load of wood. The treated wood is simply left to dry. Treated wood is resistant to degradation caused by bacteria, insects, fungi and weather conditions. In addition, the treatment makes it possible to delay the combustion of the wood. One of the main advantages of using lanthanides is their relative safety, which is important during the implementation of the process, the subsequent handling or leaching or when there is sludge formation.

Dans toutes les variantes des procédés de l'invention, on met en contact le bois avec une solution traitante et il se produit une pénétration de celle-ci.In all the variants of the methods of the invention, the wood is brought into contact with a treating solution and penetration of the latter occurs.

Sans, toutefois, limiter l'invention à l'interprétation qui en est faite, on pense que le terme "pénétration" n'est pas suffisant pour décrire et expliquer les résultats inattendus et supérieurs du bois traité avec les compositions aqueuses de lanthanide. La présente invention fournit une fixation permanente des éléments au bois. Par fixation permanente, également appelée liaison ou réticulation dans la présente demande, on entend que l'ion lanthanide est fixé aux fibres de telle sorte qu'il n'est plus possible qu'il soit lixivié par l'eau. Comme démontré ci-après dans les exemples, le bois traité avec les lanthanides sous pression présente une plus grande quantité d'ions lanthanide liés après le vieillissement que lorsqu'il est testé juste après le traitement. Le bois bien imprégné à la pression atmosphérique et lixivié juste après, présente des quantités, mais plutôt faibles, d'ions lanthanides liés. On a constaté que si la durée est suffisante, les lanthanides qui ont pénétré dans le bois ou l'ont imprégné vont graduellement se fixer de manière permanente dans le bois, à condition que le bois n'ait pas été exposé à une lixiviation avant sa réticulation. On peut empêcher une lixiviation prématurée en protégeant simplement le matériau traité de toute exposition au ruissellement excessif des eaux ou en recouvrant sa surface par tout moyen approprié. On pense que la quantité d'ions lanthanide (exprimée en pourcentage d'oxyde) liée au bois de manière permanente devrait être d'au moins 0,1% du poids total dans le but d'assurer un effet protecteur. Dans des conditions extrêmes, il est préférable, bien sûr, de mettre en oeuvre des quantités plus importantes, à savoir autant que le bois peut en absorber.Without, however, limiting the invention to the interpretation made of it, it is believed that the term "penetration" is not sufficient to describe and explain the unexpected and superior results of the wood treated with the aqueous lanthanide compositions. The present invention provides a permanent attachment of the elements to the wood. By permanent fixation, also called bond or crosslinking in the present application, is meant that the lanthanide ion is fixed to the fibers so that it is no longer possible for it to be leached by water. As demonstrated below in the examples, the wood treated with the lanthanides under pressure has a greater amount of bound lanthanide ions after aging than when it was tested just after the treatment. The wood, well impregnated at atmospheric pressure and leached just after, presents quantities, but rather small, of bound lanthanide ions. It has been found that if the duration is sufficient, the lanthanides which have penetrated into the wood or impregnated it will gradually settle permanently in the wood, provided that the wood has not been exposed to leaching before its crosslinking. Premature leaching can be prevented by simply protecting the treated material from exposure to excessive runoff or by covering its surface by any suitable means. It is believed that the amount of lanthanide ions (expressed as a percentage of oxide) permanently bound to the wood should be at least 0.1% of the total weight in order to provide a protective effect. In extreme conditions, it is preferable, of course, to use larger quantities, namely as much as the wood can absorb.

Les mécanismes de protection du bois traité par les lanthanides ne sont pas bien compris. Il semble qu'ils soient différents des mécanismes d'action des agents de protection classiques, les lanthanides n'étant généralement pas considérés comme toxiques.The protection mechanisms of wood treated with lanthanides are not well understood. They appear to be different from the mechanisms of action of conventional protective agents, as lanthanides are generally not considered to be toxic.

Les exemples qui suivent décrivent des modes de réalisation particuliers de l'invention. Les exemples ne doivent pas être interprétés comme une limitation de la portée de l'invention.The examples which follow describe particular embodiments of the invention. The examples should not be interpreted as limiting the scope of the invention.

― EXEMPLES : - EXAMPLES : Exemple 1: traitement sous pression: Example 1: pressure treatment :

On a effectué une série d'essais de traitement sous pression au cours de laquelle on a traité du pin jaune du Sud (USA) avec des dérivés de lanthanide en utilisant un procédé connu dans l'état de la technique pour traiter le pin jaune du Sud avec le CCA. On introduit dans un appareil sous pression de petits morceaux de pin séché au four. On ajoute des compositions aqueuses contenant des dérivés de lanthanide dans l'appareil en une quantité suffisante pour immerger le bois. On maintient la pression en utilisant de l'azote. A la fin du traitement, on retire les échantillons, on les laisse s'égoutter et on les sèche à l'air.A series of pressure treatment tests was carried out in which southern yellow pine (USA) was treated with lanthanide derivatives using a method known in the prior art for treating yellow pine from South with the CCA. Small pieces of oven-dried pine are introduced into a pressure device. We add aqueous compositions containing lanthanide derivatives in the apparatus in an amount sufficient to immerse the wood. The pressure is maintained using nitrogen. At the end of the treatment, the samples are removed, allowed to drip and air dried.

Afin de déterminer la quantité de lanthanide lié de manière permanente au bois, on lave à l'eau courante l'échantillon de bois traité pendant 12 heures. On sèche ensuite le bois lavé, et on détermine le pourcentage de cendres mesuré après combustion de l'échantillon et calcination du résidu à 1000°C. Le pourcentage de "cendres" avant le traitement est soustrait du pourcentage de "cendres" du bois traité afin de déterminer la quantité de lanthanide lié de manière permanente.In order to determine the quantity of lanthanide permanently bound to the wood, the treated wood sample is washed with running water for 12 hours. The washed wood is then dried, and the percentage of ash measured is determined after combustion of the sample and calcination of the residue at 1000 ° C. The percentage of "ash" before treatment is subtracted from the percentage of "ash" of the treated wood in order to determine the amount of lanthanide permanently bound.

Les études de la détérioration du bois de pin traité avec les dérivés de lanthanide montrent que l'on obtient déjà un effet bénéfique lorsque la quantité de cendres due au lanthanide est de l'ordre de 0,25%.Studies of the deterioration of pine wood treated with lanthanide derivatives show that a beneficial effect is already obtained when the quantity of ash due to lanthanide is of the order of 0.25%.

On met en évidence que l'échantillon est efficacement protégé contre toute décomposition et dégradation dues aux attaques de micro-organismes, des champignons et des insectes.It is shown that the sample is effectively protected against any decomposition and degradation due to attacks by microorganisms, fungi and insects.

Les résultats sont donnés dans le tableau 1. Tous les traitements, sauf indication contraire, sont effectués à température ambiante. Le pin brut utilisé pour les tests 1-18 contient environ 0,08% de cendres. Le pin brut utilisé dans les autres tests contient environ 0,12% de cendres.The results are given in Table 1. All the treatments, unless otherwise indicated, are carried out at ambient temperature. The raw pine used for tests 1-18 contains approximately 0.08% ash. The raw pine used in the other tests contains approximately 0.12% ash.

A titre de référence, on détermine le pourcentage de "cendres" d'un échantillon commercial de pin jaune du Sud traité avec le CCA.

Figure imgb0001
Figure imgb0002
Figure imgb0003
 For reference, the percentage of "ashes" of a commercial sample of southern yellow pine treated with CCA is determined.
Figure imgb0001
Figure imgb0002
Figure imgb0003

Les résultats des tests montrent qu'il y a plus de dérivé de lanthanide lié au bois de manière permanente quand on applique une pression plutôt que lorsqu'on procède à la pression atmosphérique. En coutre, durant le vieillissement après traitement, le pourcentage de cendres augmente. Ceci indique que le processus de réticulation se poursuit sur plusieurs jours. Le tableau II illustre les avantages d'un vieillissement.

Figure imgb0004
The test results show that there is more lanthanide derivative permanently attached to wood when pressure is applied rather than when atmospheric pressure is applied. In coulter, during aging after treatment, the percentage of ash increases. This indicates that the crosslinking process continues over several days. Table II illustrates the benefits of aging.
Figure imgb0004

― Exemple 2: traitement de surface:- Example 2: surface treatment :

On traite du bois de pin jaune du Sud avec des dérivés de lanthanide par immersion, pulvérisation ou application à la brosse avec une composition comprenant une solution aqueuse d'un dérivé de lanthanide. On laisse le bois traité sécher et vieillir pendant plusieurs jours.Southern yellow pine wood is treated with lanthanide derivatives by immersion, spraying or brushing with a composition comprising an aqueous solution of a lanthanide derivative. The treated wood is left to dry and age for several days.

Pour déterminer la teneur des échantillons en ions lanthanide liés, on lixivie les échantillons à l'eau courante comme décrit dans l'exemple 1, puis on les réduit en cendres. Lorsque la lixiviation intervient juste après le traitement, les résultats montrent qu'une certaine quantité d'ions lanthanide est liée de manière permanente (cf. exemple 1, tests 5, 13, 16, 19, 22, 25). Lorsque la lixiviation intervient après la période de vieillissement de plusieurs jours ou mois après le traitement, on trouve des quantités plus importantes d'ions lanthanide liés.To determine the content of the samples of bound lanthanide ions, the samples are leached under running water as described in Example 1, then reduced to ashes. When leaching takes place immediately after treatment, the results show that a certain quantity of lanthanide ions is permanently linked (cf. example 1, tests 5, 13, 16, 19, 22, 25). When leaching occurs after the aging period of several days or months after treatment, greater amounts of bound lanthanide ions are found.

― Exemple 3: traitement sous vide:- Example 3: vacuum treatment :

On place des échantillons normalisés, n'ayant subi aucun préconditionnement, dans un réacteur à deux cols, équipé d'une ampoule de coulée contenant une solution aqueuse de nitrate de cérium à 2%. Dans le réacteur, on établit une pression réduite (d'environ 2,66.10² Pa) qu'on maintient pendant 10 heures. On remplit le réacteur avec la solution de nitrate de cérium et les échantillons sont maintenus immergés pendant environ 4 heures.Standardized samples, having undergone no preconditioning, are placed in a two-necked reactor, equipped with a dropping funnel containing a 2% aqueous solution of cerium nitrate. In the reactor, a reduced pressure is established (about 2.66.10² Pa) which is maintained for 10 hours. The reactor is filled with the cerium nitrate solution and the samples are kept immersed for about 4 hours.

Après égouttage et séchage à l'air pendant 10 heures, on lixivie l'échantillon pendant toute une nuit et on le réduit en cendres.

Figure imgb0005
After draining and air drying for 10 hours, the sample is leached overnight and reduced to ashes.
Figure imgb0005

Les résultats montrent que le pourcentage de cérium lié de manière permanente (exprimé en CeO₂) est de 1,24%.The results show that the percentage of permanently bound cerium (expressed as CeO₂) is 1.24%.

Claims (22)

1. Process for the treatment of wood, characterised in that it consists in having a composition comprising an aqueous solution of at least one lanthanide derivative penetrate into the wood, which was previously conditioned or not conditioned, the simultaneous use of a cerium and CCA derivative being excluded from the scope of protection of the present invention,
― by means of a technique or a combination of several known techniques selected such that the desired degree of penetration is obtained depending on the intended use and a permanent bond of the lanthanide ions with the wood fibres is produced.
2. Process according to Claim 1, characterised in that the lanthanide is cerium, lanthanum, praseodymium, or neodymium.
3. Process according to one of Claims 1 and 2, characterised in that the lanthanide derivative is a lanthanide nitrate.
4. Process according to one of Claims 1 to 3, characterised in that the composition comprises a mixture of lanthanide derivatives or a mixture of different lanthanide derivatives.
5. Process according to one of Claims 1 to 4, characterised in that the composition comprises one or more cerium compounds selected from the group comprising: Ce(NO₃)₃, Ce(NO₃)₄, CeCl₃, Ce₂(SO₄)₃, Ce(SO₄)₂, Ce(NO₃)₄, 2NH₄NO₃, cerous acetate, cerous methacrylate, cerous lactate, cerous propionate and cerous toluenesulphonate.
6. Process according to one of Claims 1 to 5, characterised in that the aqueous solution comprises between about 0.1% and about 10% by weight of one or more lanthanide derivatives.
7. Process according to Claim 6, characterised in that the aqueous solution comprises between about 0.5% and about 2% by weight of one or more lanthanide derivatives.
8. Process according to one of Claims 1 to 7, characterised in that it consists in:
― bringing the wood into contact with a composition comprising an aqueous solution of at least one lanthanide derivative,
― in allowing the wood/solution complex to dry in air,
― in aging the wood/solution complex for a period sufficient for obtaining a bond between the lanthanide element and the wood.
9. Process according to Claim 8, characterised in that the contacting of the wood with the treatment composition is achieved by immersion, pulverisation or by brushing.
10. Process according to one of Claims 1 to 7, characterised in that it consists in:
― subjecting the wood to a treatment under vacuum,
― introducing a composition comprising an aqueous solution of at least one lanthanide derivative and bringing the wood into contact with said composition for a period sufficient for obtaining a bond between the lanthanide element and the wood.
11. Process according to Claim 10, characterised in that a hydrostatic pressure is established and maintained after having contacted the treatment composition so as to obtain a high degree of bonding.
12. Process according to one of Claims 1 to 7, characterised in that it consists in:
― immersing the wood in a composition comprising an aqueous solution of at least one lanthanide derivative and
― maintaining an elevated pressure for a period sufficient for obtaining a bond between the lanthanide element and the wood.
13. Process according to Claim 12, characterised in that the wood is brought into contact with the solution under pressure, said pressure being greater than atmospheric pressure.
14. Process according to Claim 13, characterised in that the pressure is between about 10 psi (6.895 × 10⁴ Pa) and about 300 psi (2.0684 × 10⁶ Pa).
15. Process according to Claim 14, characterised in that the pressure is between about 50 psi (3.4473 × 10⁵ Pa) and about 280 psi (1.9305 × 10⁶ Pa).
16. Process according to Claim 12, characterised in that the period is between about 30 minutes and about 10 hours.
17. Process according to Claim 16, characterised in that the period is between about 3 hours and about 6 hours.
18. Process according to Claim 12, characterised in that the immersion tales place at a temperature below about 95°C.
19. Process according to Claim 18, characterised in that the immersion tales place at ambient temperature.
20. Process according to Claim 19, characterised in that the immersion tales place between about 20°C and about 30°C.
21. Process according to one of Claims 1 to 20, characterised in that it leads to a composition comprising wood or wood derivatives and lanthanides or lanthanide derivatives, in which composition the lanthanide or the lanthanide derivative, expressed as lanthanide oxide represents between about 0.1% and about 5% by weight of the composition.
22. Process according to Claim 21, characterised in that the lanthanide derivative represents between about 0.10% and about 2.0% by weight of the composition.
EP19880400352 1987-02-20 1988-02-17 Compositions for the treatment of wood and processes for the treatment of wood Expired - Lifetime EP0282380B1 (en)

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US17159 1987-02-20
US07/017,159 US4743473A (en) 1987-02-20 1987-02-20 Method of preserving wood with lanthanide derivatives
US07/121,616 US4842898A (en) 1987-02-20 1987-11-17 Method of preserving wood with lanthanide derivatives lanthanide derivatives
US121623 1987-11-17
US07/121,623 US4889771A (en) 1987-02-20 1987-11-17 Method of preserving wood with lanthanide derivatives
US121616 1987-11-17

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