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Title:
METHOD OF PINE WOOD IMPREGNATION
Document Type and Number:
WIPO Patent Application WO/2020/214040
Kind Code:
A1
Abstract:
The method of pine wood impregnation by vacuum-pressure saturation with a solution of chromium-free, salt wood preservative based on inorganic copper and boron compounds as well as organic components where a negative pressure is generated in the first phase, the second one fills the autoclave with a impregnant, the third creates a pressure of several bars, which pushes the impregnate deep into the wood and then atmospheric pressure is restored and the autoclave has a vacuum and excess impregnation is removed from the wood surface is characterized by the fact that the wood is subjected to vacuum-pressure solution of a chromium-free, salt wood preservative based on inorganic copper compounds (copper-based HDO) and boron and organic ingredients called Wolmanit CX-10 with the addition of ionic liquid (DDA) (N03) at a concentration of 3.5% with 3.0% by weight, under negative pressure (0.7 ± 0.1) kPa, during 60 minutes, and atmospheric pressure during 120 minutes, at a temperature of 20 ± 1 ° C). For pressure impregnation, wood with a maximum moisture content of up to 28% is used. Retention of Wolmanit CX-10 in the wood of pine samples Pinus sylvestris L. saturated with the cold bath method - 20 ± 1 0 C, lasts 6 hours with Wolmanit CX-10 solution at a concentration of 3.5% by weight or Wolmanit CX-10 solution at a concentration of 3, 5% with 3.0% by weight with the addition of ionic liquid [DDA] [N03]. Quaternary ammonium salt penetrates into sapwood similar to copper penetration with saturation with Wolmanit CX-10 solution with the addition of [DDA] [N03], and in heartwood this salt penetrates more than twice as deep as copper.

Inventors:
RABCHUN OLEG (UA)
Application Number:
PCT/PL2019/000040
Publication Date:
October 22, 2020
Filing Date:
April 29, 2019
Export Citation:
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Assignee:
EURO LOGISTICS GROUP SP Z O O (PL)
International Classes:
B27K3/02; A01N33/12; B27K3/08; B27K3/16; B27K3/22; B27K3/52
Domestic Patent References:
WO2008012757A12008-01-31
Foreign References:
Other References:
DATABASE COMPENDEX [online] ENGINEERING INFORMATION, INC., NEW YORK, NY, US; 2004, PERNAK J ET AL: "Ionic liquids in wood preservation", XP002800162, Database accession no. E2004268234860
Attorney, Agent or Firm:
SAS Katarzyna (PL)
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Claims:
Claims

1. The method of pine wood impregnation by means of differential pressure impregnation with a solution of chromium-free, salt wood preservative based on inorganic copper and boron compounds as well as organic components where vacuum is generated in the first phase, the second is filled with impregnation autoclave in the third pressure of several bars, which injects the impregnate deep into the wood and then atmospheric pressure is restored and the autoclave vacuums and excess impregnation is removed from the wood surface, characterized in that the wood is subjected to vacuum-pressure saturation of a chromium- free, salt wood preservative based on inorganic copper compounds (based on copper) -HDO) and boron and organic ingredients called Wolmanit CX-10 with the addition of ionic liquid (DDA) (N03) at a concentration of 3.5% with 3.0% by weight, under negative pressure (0.7 ± 0.1) kPa , during - 60 minutes, and atmospheric pressure - during 120 minutes, at a temperature of 20 ± 1 ° C).

2. The impregnation method according to claim 1, characterized in that for pressure impregnation wood with a maximum moisture content of up to 28% is used.

3. The impregnation method according to claim 1, characterized in that the retention of Wolmanit CX-10 in the wood of pine samples Pinus sylvestris L. saturated with a cold bath method - 20 ± 1 ° C, lasts 6 hours with a solution of Wolmanit CX-10 at a concentration of 3, 5% by weight or Wolmanit CX-10 solution at a concentration of 3.5% with 3.0% by weight with the addition of ionic liquid [DDA] [N03].

4. The impregnation method according to claim 1, characterized in that the quaternary ammonium salt penetrates into the sapwood similar to copper penetration with saturation with Wolmanit CX-10 solution with the addition of [DDA] [N03], and in the heartwood this salt penetrates more than twice as deep than in copper.

Description:
Method of pine wood impregnation

The subject of the invention is a method of impregnating pine wood and in particular sapwood and heartwood.

From the patent description WO2019004846 a method of processing wood products is known. In particular, the product formula of a single-phase solution combining a wood preservative with a flame retardant component to produce a durable fire retardant wood product The durable component includes a range of copper and non-copper wood preservatives, while the flame retardant component includes alkali metal silicates and alkali metal aluminate compounds. A stable, flammable working solution is subjected to chemical impregnation (treatment), followed by a thermal process (fixing), which blocks the chemical in the wood, so it cannot be leached. Durable fire retardant wood products are tested for their improved fire resistance. When heated, the wood degrades thermally, and combustion produces gases, vapors, tars and marks. By using the "cone calorimeter" burning method, durable wood products impregnated with a flame retardant exhibit a significant reduction in the following parameters: heat release rate (peak and average values), mass loss factor and smoke generated values (smoke quenching area) compared to radiant pine.

From Japanese patent JPH11904, impregnation of preserving wood is known, which is hindered by a specific membranous substance accumulating in the edge part of the cell wall characteristic for wood, by means of preservative wood. The liquid in 500 ml, from which 0.1-5 kgf / cm2 of gaseous carbonic acid dissolves, penetrates into wood, such as Oregon pine, Pacific hemlock and cedar. The composition of the above-mentioned liquid contains 2-5 different materials or wood improvers, such as colloidal silica, boric acid, water-soluble chitosen, aluminum hydroxide, divalent copper, silver nitrate, zinc, chromium, anatase type titanium oxide, resins, carbon compound, other ionised inorganic substances and the like to obtain efficient impregnated solidified wood.

In turn, from GB 1307830, a replica of wood or wood floor is known, it is produced by impregnating said wood or wood floor at atmospheric pressure with a solution of one or more thermally decomposing metal salts, which solution enters their fibers, drying the impregnated material and single heating in a reducing atmosphere by destroying wood (flour), breaking salt (salts) into metal, and sintering the resulting metal to form a coherent metal body with porosity corresponding to the pores in the fibers, as well as gaps between them in the starting material. The wood can be pine or balsa, and non-cellulosic ingredients can be initially removed from wood flour or resin wood, e.g. by boiling in NaOH solution; impregnation, e.g. with NiC12 to form a Ni body, preferably has a pressure of # 20 p.s.i.g; the porous Ni body thus formed can be impregnated with Ni (OH) 2 to form an alkaline battery plate. Similarly, GB 1497058 is known for increasing the strength of wood by impregnation with plastic includes placing wood in a container, draining the container to remove moisture and / or gases (air) from the wood, impregnating wood under pressure with a mixture of an ethylenically unsaturated polymerized liquid and a curing agent, which is tertiary butyl-peroxide compound and which is dormant (potentially active) at room temperature and elevated temperature up to 30 ° C, but which is quickly activated at higher temperatures or by high-energy electromagnetic radiation, and then affects in situ polymerization of the polymerizable liquid by heating wood in an oven at 60-150 ° C or by irradiating wood with high energy electromagnetic radiation in a radiation chamber at room temperature. The polymerizable liquid is suitably a solution of unsaturated polyester in styrene or vinyltoluene or methyl methacrylate. The curing agent may be tertiary butyl perbenzoate, butyl peroxide, 2,2-bis (t- butylperoxy) butane, 2,5 - dimethyl - 2,5 - di (t - butylperoxy) - hexane, t - butyl hydroperoxide, 2.5 -dimethyl-2,5 - (di-t-butylperoxy) hexin-3, n-butyl 4,4-bis (t-butylperoxy) valerate or 1,1-bis- (t-butylperoxy) -3, 3.5 -trimetylocykloheksan. X-rays are a suitable form of useful radiation.

From GB 1364330, a fire retardant for fireproofing of wood, especially wood for underground constructions, is known as an aqueous solution containing from 10 to 45% by weight of calcium chloride and from 0.1 to 3.0% by weight of a non-foaming and non-ionic wetting agent. The wetting agent may be an alkylphenol polyglycol ether. Wood, which may be spruce, pine or oak, can be impregnated by immersion in a solution in an open trough at atmospheric pressure for a period of 6 to 60, preferably 6 to 48 hours. Alternatively, impregnation can be carried out by spreading or spraying the wood onto the wood several times at intervals. This process also provides protection against rotting.

Also from the patent description WO2008145146 an oil / oil / water emulsion and a pine wood impregnation method are known. The aqueous phase of the emulsion contains an aqueous solution of boron compounds (borax, boric acid) and quaternary ammonium compounds. The first oil phase contains rapeseed oil as a dispersed phase and an emulsifier (unsaturated fatty acid or mixture thereof). The second oil phase contains polysiloxane particles dispersed on the surface of the first oil phase to improve hydrophobization. The emulsion is prepared by emulsifying polysiloxane with rapeseed oil and an emulsifier. The mixture is then emulsified with an aqueous solution using a pulsating emulsifying device with a pulse frequency of 800 to 1200 Hz. Wood impregnated by this method has good antiseptic properties against fungi decomposing wood and staining wood, as well as reduced leaching of active agents.

The aim of the invention is to develop a method of obtaining more effective protection of pine wood and other wood species, including hardwood, which will contribute to increasing the retention of the preparation in wood and increasing the depth of penetration of the active ingredient of this wood preservative.

The method of pine wood impregnation by vacuum-pressure saturation with a solution of chromium-free, salt wood preservative based on inorganic copper and boron compounds as well as organic components where a negative pressure is generated in the first phase, the second one fills the autoclave with a impregnant, the third creates a pressure of several bars, which pushes the impregnate deep into the wood and then atmospheric pressure is restored and the autoclave has a vacuum and excess impregnation is removed from the wood surface is characterized by the fact that the wood is subjected to vacuum-pressure solution of a chromium-free, salt wood preservative based on inorganic copper and boron compounds and organic components called Wolmanit CX-10 with the addition of ionic liquid (DDA) (N03) at a concentration of 3.5% with 3.0% by weight, at a negative pressure (0.7 ± 0.1) kPa, during 60 minutes, and atmospheric pressure - during 120 min, at a temperature of 20 ± 1 ° C).

The use of chemical additives [DDA] [N03] makes the preparation more effectively and deeper into the wood in the impregnation process. Impregnated [DDA] [N03] and component Wolmanit CX-10 thermally modified wood acquires new, better quality indicators, especially in terms of some physical and mechanical properties and color. The addition of [DDA] [N03] to the Wolmanit CX 10 solution also helps to preserve the wood structure and increase the depth of penetration of the active pine wood protection component. The subject of the invention has been approximated in the exemplary embodiments contained in the following examples.

Example 1.

Vacuum-pressure saturation with Wolmanit CX-10 solution was subjected to 50 mm wide and 60 mm wide white wood samples. Those 50 mm wide absorbed an average of 16.3 kg.m-3 Wolmanite CX-10 (from 10.1 to 21.1 kg.m-3), and 60 mm wide white wood samples on average 19.0 kg.m -3 Wolmanite CX-10 (from 17.0 to 22.5 kg.m-3). Appropriate amounts of Wolmanite CX-10 absorbed by such wood sapwood samples with vacuum-pressure solution of Wolmanit CX-10 with the addition of [DDA] [N03] were for samples with a width of 50 mm on average 22.5 kg.m-3 (from 19, 7 to 24.1 kg.m-3), and for samples 60 mm wide on average 24.9 kg.m-3 (from 23.1 to 25.9 kg.m-3). The addition of [DDA] [N03] resulted, with the applied vacuum-pressure saturation parameters, increasing the retention of Wolmanite CX-10 in sapwood by about 31 to 38%.

Example 2.

50mm wide heartwood samples were absorbed on average 1.4 kg.m-3 Wolmanite CX-10 (from 0.9 to 2.5 kg.m-3) on vacuum-pressure saturation with Wolmanit CX-10 (0.9 to 2.5 kg.m-3), while the samples of heartwood were 50mm wide 60 mm wide, average 2.9 kg.m-3 Wolmanite CX-10 (1.7 to 4.9 kg.m-3). Appropriate amounts of Wolmanite CX-10 absorbed by such heartwood samples during saturation with a vacuum-pressure solution of Wolmanite CX-10 with the addition of [DDA] [N03] for samples 50 mm wide was on average 2.5 kg.m- 3 (from 1, 6 to 3.5 kg.m-3), and for samples of 60 mm width 2.8 kg.m-3 (1.8 to 5.3 kg.m-3). The addition of [DDA] [N03] caused, therefore, under vacuum-pressure saturation, an increase in retention of Wolmanite CX-10 in wood samples of 50 mm wide heartwood samples by about 70%, whereas in wood samples of 60 mm wide heartwood samples this effect did not occur. When saturating sapwood samples with the bath method with Wolmanit CX-10 solution (Table 2), 50mm-wide sapwood samples absorbed on average 2.2 kg.m-3 Wolmanite CX-10 (from 1.8 to 2.8 kg.m- 3), and sapwood samples 60 mm wide on average 2.5 kg.m-3 Wolmanite CX-10 (from 2.4 to 2.6 kg.m-3). Appropriate amounts of Wolmanite CX-10 absorbed by such sapwood samples when impregnating by the bath method with Wolmanit CX-10 solution with the addition of [DDA] [N03] for samples 50 mm wide averaged 2.2 kg.m-3 (from 2.0 up to 2.4 kg.m-3), and for samples 60 mm wide on average 2.6 kg.m-3 (from 2.4 to 2.6 kg.m-3). With the addition of [DDA] [N03] in the Wolmanite CX-10 retention bath method in sapwood it remained at the same level as without this addition (50 mm wide samples) or slightly larger (60 mm wide samples). 50 mm wide heartwood samples were absorbed on average 0.7 kg.m-3 Wolmanite CX-10 (from 0.6 to 0.7 kg.m-3) while impregnating with the Wolmanit CX-10 solution by the bath method, and heartwood samples with the width of 50mm 60 mm wide, average 1.0 kg.m-3 Wolmanite CX-10 (from 0.9 to 1.1 kg.m-3). Wolmanite CX-10 retention in the wood of pine pine samples Pinus sylvestris L·. saturated with the vacuum-pressure method (vacuum (0.7 ± 0.1) kPa - 60 min, atmospheric pressure - 120 min, 20 ± 1 ° C) with Wolmanite solution CX-10 with a concentration of 3.5% (w / w) or Wolmanite CX-10 with a concentration of 3.5% with a 3.0% (w / w) addition of ionic liquid [DDA] [N03]

Table no.l

Example 3. Wolmanite CX-10 retention in the wood of pine pine samples Pinus sylvestris L. saturated with the cold bath method - (20 ± 1 ° C, 6 hours) with Wolmanit CX-10 solution at 3.5% by weight or Wolmanit CX-10 solution at a concentration of 3.5% with 3.0% (w / w) addition of ionic liquid [DDA] [N03].

Table no.2

Appropriate amounts of Wolmanite CX-10 absorbed by such heartwood samples when impregnating with the Wolmanit CX-10 solution with the addition of [DDA] [N03] were on average 0.9 kg.m-3 for samples 50 mm wide (from 0.8 up to 0.9 kg.m-3), and for 60 mm wide samples 1.2 kg.m-3 on average (from 1.0 to 1.6 kg.m-3). The addition of [DDA] [N03] resulted in the saturation of heartwood samples with the bath method, resulting in a more pronounced increase in retention of Wolmanite CX-10 than in white wood, amounting to 50% width heartwood samples in wood, while in 60 mm heartwood samples this effect was about 20%.

In the lubrication method, the depth of copper penetration in wood was on average the same level when using Wolmanit CX-10 solution with the addition of [DDA] [N03] as for wood protection with Wolmanit CX-10 solution without the addition of [DDA] [N03]. The penetration of the quaternary ammonium salt was greater in the lubrication method than that of copper (1.6 mm compared to 1.2 mm).

The penetration of the NaF standard preparation measured by fluoride ion staining was on average 2.8 mm. The addition of [DDA] [N03] in most trials contributed to a deeper penetration of copper or preparation by measuring the penetration of the quaternary ammonium salt.

Copper penetration depth in wood of Pinus sylvestris L. pine samples saturated with vacuum- pressure method (vacuum (0.7 ± 0.1) kPa - 60 min, atmospheric pressure - 120 min, 20 ± 1 ° C) with Wolmanit CX- solution 10 3.5% (w / w) or Wolmanit CX-10 3.5% solution with 3.0% (w / w) addition of ionic liquid [DDA] [N03]. Table no.3

Copper penetration depth in wood of Pinus sylvestris L. pine samples saturated with cold bath method - (20 ± 1 ° C, 6 hours) Wolmanit CX-10 solution at 3.5% (w) or Wolmanit CX-10 solution at 3 concentration , 5% with 3.0% (w / w) addition of ionic liquid [DDA] [N03]

Table no.4

Penetration depth of quaternary ammonium salt in the wood of Pinus sylvestris L. Scots pine saturated with vacuum-pressure method (vacuum (0.7 ± 0.1) kPa - 60 min., Atmospheric pressure - 120 min, 20 ± 1 ° C) with Wolmanit solution CX-10 at a concentration of 3.5% with 3.0% (w / w) addition of ionic liquid [DDA] [N03].

Table no.5

Penetration depth of quaternary ammonium salt in the wood of pine pine samples Pinus sylvestris L. saturated by cold bath method - (20 ± 1 0 C, 6 hours) with Wolmanit CX-10 solution at a concentration of 3.5% with 3.0% (w / w) liquid addition ionic [DDA] [N03].

Table no.6

Depth of penetration into the pine wood of Wolmanit 50% + 5% [DDA] [N03], lubrication method, wood moisture 12 ± 1%, penetration of quaternary ammonium salt.

Table no.7

Results of determinations of color coordinates and total color change in the L, a, b system

Table no.8

The use of functionalized ionic liquid [DDA] [N03] to increase the retention and penetration of fungicidal protective preparations applied by means of pressure is a solution for improving the parameters of wood protection intended for use in III class of use. The addition of the chemical substance [DDA] [N03] introduced allows for more effective penetration of the preparation deep into the wood in the process of pressure saturation. An additional advantage of the substance used is the fact that it hardens by binding with wood, which prevents it from being washed into the environment during the use of wood outside in class III use. The introduction as a substance supporting the penetration and retention of fungicidal preparations - ionic liquid has an effect not only in the area of improving the quality of impregnation, but also the economic aspect, as it allows a favorable change of saturation parameters (shortening of saturation time) in an industrial technological process. The addition of [DDA] [N03] to the Wolmanit CX-10 solution with equal saturation conditions promotes an increase in the product retention in wood and an increase in the depth of penetration of the active ingredient of this wood protection agent. Saturated wood is well heat treated and acquires an interesting color.

As the pine processing temperature increases, moisture absorption decreases from 68% at t = 190 ° C to 62% at t = 203 ° C. What's more, the highest moisture content (around 69%, respectively) is absorbed by thermally treated wood in the first 3.5 years of contact with water. The introduction of hydrophobic components by impregnating the samples, in particular [DDA] [N03] before modification, allows to significantly reduce their moisture absorption. Thus, samples that were heat-treated at 190 ° C, immersed in water for 13 hours, absorb only 14% moisture compared to unmodified samples.

With the increase of the modification temperature, a decrease in the co-ordinate indexes of the "blue" and "yellow" components is observed by 28-39%. The total color change of pine wood by heat modification is on average from 27 to 36%. The occurrence of didecyldimethylammonium nitrate and Wolmanit CX-10 in the structure of the tested wood samples can be considered as a decisive factor causing unusual color changes in the pine models presented in the modification process.

Impregnation with Wolmanit CX 10 of previously modified [DDA] [N03] pine wood in the process of heating at high temperature (heat treatment) leads to a heterogeneous change in the color parameters of the early and late pine wood zone and gives products uniqueness. Mixed abrasion models, which are characterized not only by the abundance of dark shades of heat- treated pine wood (dark brown to blue), but also by the presence of clear streaks of different tones, which in our opinion is a manifestation of heterogeneous absorption of the impregnant by white zones, are particularly distinguished by this and heartwood caused by pine anatomical features. The products have better properties, especially in terms of resistance to biological corrosion, heat resistance, moisture absorption; reduction of thermal conductivity and relatively constant indicators with specific power and impact resistance. The depth of copper penetration in the vacuum-pressure method at saturation of wood with Wolmanit CX- 10 solution with the addition of [DDA] [N03] turned out to be significantly greater in both sapwood and heartwood wood (by nearly 50% in white and over 100% in wood) tough) than with saturation with a solution of Wolmanit CX-10 alone. The penetration of the quaternary ammonium salt was similar to that of copper when saturating with Wolmanit CX-10 solution with the addition of [DDA] [N03]. Also at saturation by the bath method (Tab. 6-8), an increased depth of copper penetration in sapwood was found when using Wolmanit CX-10 solution with the addition of [DDA] [N03], compared to saturation with Wolmanit CX-10 solution without the addition of [DDA] [N03] - an increase of around 20%. In heartwood wood no such change was found, with very low penetration of the preparation (level 0.3 - 0.4 mm). The penetration of the quaternary ammonium salt into the sapwood was similar to that of copper when saturating with Wolmanit CX-10 solution with the addition of [DDA] [N03], and in the heartwood this salt penetrated more than twice as deep as in copper. Determination of color coordinates and total color change in the L, a, b system showed that wood saturation with Wolmanit CX-10 solution without and with the addition of [DDA] [N03] causes similar changes in the value of color coordinates and total color change. The wood darkens, acquires a distinct greenish color, especially sapwood, in which larger amounts of the preparation solution are introduced. Thermal treatment deepens the wood color changes, further darkens the color and changes the color. Unsaturated wood turns brown, wood saturated with Wolmanit CX-10 solution without and with the addition of [DDA] [N03] acquires colors in brown-navy blue shades.