MXPA99004072A - Method of pressure treating boards - Google Patents

Abstract

A method for pressure treating wood products is provided wherein wood products are pressure treated in an aqueous solution of a silicate, a rheology modifier, a wetting agent and, optionally, borax;the aqueous solution having a pH of at least 9.0. A suitable dye can be added to the aqueous solution to color the wood product. The present invention is also directed to an aqueous solution for pressure treating wood and a wood product prepared according to the method of the present invention.

Description

METHOD AND COMPOSITION FOR INJECTING PRESSURE TABLES FIELD OF THE INVENTION The present invention focuses on a method, which does not use formaldehyde, for the treatment of products of wood products, especially sawn wood, green, to reinforce wood products and convert them. in fire retardant products and resistant to humidity and insects.

BACKGROUND OF THE INVENTION The prior art publications describe the treatment of wood products with chemicals such as silicates, creosote, copper naphthenate, pentachlorophenol and chromated copper arsenate, to preserve wood products and render them flame retardant and insect repellent. After the treatment the wood products can be painted, soaked or injected REF. : 30186 pressure, to coat and / or impregnate wood products. U.S. Patent No. 3,974,318 issued to Lilla describes one such process. In the Lilla patent, a water-soluble silicate composition is applied to a wood product, and the product is subsequently treated with a water-soluble metal salt compound to form a water-insoluble metal silicate in the product. of wood. Although the methods and compositions of the prior art are suitable for the treatment of sawnwood, dry, and manufactured wood products (engineered), no suitable products or methods have been found for the treatment of sawn, green, or other wood. wood products that have a high water content. . Therefore, an object of the present invention is to provide a method of treating wood products, and a compound, suitable for the treatment of wood products, and for the treatment of sawnwood, green, as well as providing a method and superior composition to fully treat sawn timber, dry, and manufactured wood products.

BRIEF DESCRIPTION OF THE INVENTION The present invention is directed to a method and composition for the treatment of wood products as well as to a wood product, treated, prepared in accordance with the methods of the present invention. The method provides the treatment of wood products with a silicate-based solution that will completely penetrate and preserve wood products, including sawn, green wood. The method includes the injection under pressure of wood products, in an aqueous solution of sodium silicate which also includes a wetting agent, a rheology modifier at a pH of at least 9.0 and, preferably, at a pH of at least 13.0. More preferably, the aqueous solution includes borax and / or a bactericide or fungicide. The addition of the rheology and wetting agent modifier to the solution allows the chemicals to completely penetrate the wood product regardless of whether the wood product is sawnwood, green, or a dry wood product and / or a wood product engineered. The pressure injection method of the present invention includes the following steps: placing the material in a pressure vessel and applying a vacuum; contacting the material with an aqueous solution and increasing the pressure in the pressure vessel; drain the aqueous solution and reduce the pressure, preferably by applying a vacuum; and drying the treated wood product. In an alternative method, the wood particles are mixed in a liquid paste of the aqueous solution and a gum; the liquid paste is injected into a press, for example into a steam press, and the liquid paste is pressed to form a table or other engineered wood product. The engineered wood product can be an agglomerate, a table made of wood particles or a fiberboard oriented. Then the wood product is cured.

As a further alternative, the aqueous solution and / or the other additives can be injected directly into the press before pressing and curing. The composition of the present invention is an aqueous solution having a pH of at least 9.0, preferably from 10 to 14 and, most preferably, from 13.0 and includes silicate, a wetting agent and a rheology modifier, the solution preferably including borax and / or a bactericide or fungicide. Finally, the present invention also focuses on a wood product, injected under pressure, prepared by one of the methods described above.

BRIEF DESCRIPTION OF THE DRAWINGS Figures la-c are graphical representations of the distance covered by the flames, of the temperature and smoke developed, versus time, in the analysis of fiber oriented tables (TFO) of 1.6 cm (5/8 pig) prepared from according to the method of the present invention.

Figures 2a-c are graphical representations of the distance covered by the flames, temperature and smoke developed, versus time, in the analysis of a 19 cm (3/4 in) table made of wood particles prepared in accordance with the method of the present invention.

Figures 3a-c are graphical representations of the distance covered by the flames, temperature and smoke developed, versus time, in the analysis of a plywood of Oregon Pine, 1.6 cm (5/8 in) prepared in accordance with the method of the present invention.

DESCRIPTION OF THE PREFERRED MODALITIES The present invention focuses on a method and composition for the treatment of wood products, which preserves wood products and renders them resistant to fire, moisture and insects. The term "wood products" refers, in general, to products derived from wood, but is not exclusively limited to oriented fiber board, medium density agglomerate (ADM), plywood, board made of wood particles, paper products and natural wood products, which include both green and dry sawn wood. The treated wood products are generically useful for construction purposes. More specifically, for the purpose of example only, the treated products can be used in floors, fire safety doors, beams and exterior columns, materials and laminates for fire panels, exterior laminates including lining boards, manufacture of dressers , manufacture of furniture, railway sleepers, logs to decorate the landscape, veneering of floors, wood pirorr et ardante, door beams, breakwaters, contraptions, material for facades, and in the manufacture of windows. The method of the present invention uses an aqueous solution for the treatment of wood products, which includes a silicate, a wetting agent and a rheology modifier. The pH of the solution is preferably greater than 9.0, preferably from 10 to 14 and, most preferably, 13.0. During use, for example, when the aqueous solution is used in the diluted form, it is desirable to maintain the pH of the solution at a value of 11.2 to 11.4. The solution may include borax as an insecticidal agent and / or a bactericidal or fungicidal agent. The relative amounts of the components of the aqueous solution can be varied, and the ranges of the components of the solution are preferably between 18% and 60% sodium silicate, 0.01% and 2% wetting agent and from 0.01% to 2%. % rheology modifier. Optionally, between 1% and 10% borax and / or 0.1% and 1% bactericidal or fungicidal can be included in the solution. All percentages that refer to the composition of the aqueous solution are by weight. The remainder of the solution includes water and any other desirable additive, such as a suitable dye or dyeing agent. The aqueous solution consists most preferably of 61.8% water, 38% sodium silicate, 0.1% wetting agent and 0.1% rheology modifier. The solution optionally includes 5% borax, with appropriate adjustments in water content. An optional, additional ingredient is 0.2% of a bactericide or fungicide, with appropriate adjustments in water content. Examples of rheology modifiers include, but are not limited to, thickening agents including cellulosic agents, such as hydroxymethylcellulose, lignum and carboxymethylcellulose, and acrylic thickeners. Examples of suitable wetting agents include, although not limited to, the sodium silicate, the sodium dodecylsulfate, the sodium hydrogen sulfate and the trisodium phosphate. The aqueous solution is preferably prepared so that it has 21% solids, or active ingredients, as measured by the refractive index. For use, the aqueous solution can be diluted to a range between 0 and 21% solids or active ingredients. The proper dilution for a given wood product is determined empiric. For example, it was determined empiric that the ADM and the board made of wood particles are treated in the best way with a solution of 8% solids while the railway sleepers (red and white oak) are treated in the best way with a solution of 12% solids. The bactericide or fungicide can be any suitable agent that does not substanti affect the ability of the aqueous solution to preserve the treated wood products. However, it was found that 0.2% of CIL-75 (Dow) or methyl acetaphor are suitable for this purpose. These agents have not previously been recognized as useful in wood processing. In addition, these agents have added benefit since they are environment safe and are approved for use in food service areas. To treat wood products in accordance with the present invention, the wood product is placed in a container under pressure. The pressure vessel gate closes, and a vacuum of approximately 15.9 kg (35 pounds) is applied. The chamber is flooded with the aqueous solution described above. A pressure of 18.2 kg (40 pounds) to 73 kg (160 pounds) is applied to wood products in the aqueous solution. Most preferably, a pressure of 18.2 kg (40 pounds) is applied to board made of wood particles, ADM and TFO and a pressure of 63.6 kg (140 pounds) is applied to natural wood products. During the injection under pressure, the aqueous solution is circulated under pressure for a time of between 20 and 90 minutes. Wood products are preferably treated for 30 minutes in the case of wood particle board, ADM and TFO and 90 minutes in the case of natural wood products. The chamber is drained and a vacuum of approximately 13.6 kg (30 pounds) is maintained for 10 minutes. The chamber is opened and the treated wood product is removed. The treated wood product is then placed either in a rotary drying oven and dried slowly for 24 hours with hot air and steam, air-dried for 30 days or dried with microwaves for up to 8 hours.

The aqueous solution of the present invention can also be used in a variety of commonly used methods for the preparation of "engineered" wood products such as, without limitation, the board manufactured from wood particles, agglomerate and fiberboard oriented . These products are generally prepared by forming a liquid paste of fibers or wood particles and an appropriate gum. The liquid paste is placed in a steam press, to form the wood product. The wood product is subsequently cured. According to one embodiment of the present invention, the cured wood product is injected under pressure in the presence of the aqueous solution, as described above. The wood product can also be treated with the aqueous solution in the first stage. In a version of the method of the present invention, the aqueous solution and some additional additives are mixed in the liquid pulp of wood or rubber fibers or particles, before placing the liquid paste in the steam press. Alternatively, the aqueous solution and the additives are added to the press before placing the liquid paste in the press. Importantly, the superior penetration and conservation activity of the aqueous solution according to the present invention allows the addition of the aqueous solution and / or any additional additives at any time during the preparation of the manipulated wood product. by engineering, or after, as long as the addition of the aqueous solution is physically possible.

EXAMPLES The retarded capacity of this process was evaluated in accordance with the following procedure by the Harwood Plywood and Veneer Association Laboratory and Testing Service, a commercial analysis service conforming to the designation ASTM E 84, "Standard Analysis Method for Surface Combustion Characteristics of Construction Materials ". This tunnel method of 7.62 meters (25 feet) is also described by NFPA No. 255 and UL No. 723.

The purpose of the test or analysis is to determine the relative behavior of the test material under standardized fire exposure. The results are presented for the spreading of the flames and smoke - developed. The values obtained from the combustion of the analysis material represent a comparison with that of the table for cement reinforced with inorganic material, of 0.635 cm (l / '4 pig), expressed as zero, and that of the red oak floor expressed as 100. The oven was preheated to a minimum of 65.6 ° C (150 ° F) as measured by an 18 AWG thermocouple embedded in the cement 0.32 cm (1/8 pig) below the floor surface of the chamber, 7.1 m (23-1 / 4 ft) from the centerline of the ignition burners. The furnace is then cooled to 40.6 ° C (± 4.4 ° C) (105 ° F (± 5 ° F)) as measured by an embedded thermocouple 0.32 cm (1/8 of an inch) below the floor surface of the analysis chamber, 4 m (13 ft.) from the end of the fire. Previous analyzes of 10 minutes with a table for cement reinforced with inorganic material, provided zero reference for the spread of the flames. Analysis of 10 periodic minutes with red oak floor of selected class, not finished, provided the reference of 100 for the spread of the flames and the development of smoke. The wood products analyzed in the following examples were treated as follows. The material was placed in a pressure vessel. Then the door was closed and a vacuum of 15.9 kg (35 pounds) was achieved. The chamber was flooded with a 32% by volume solution, WOF-24, TWF-27 or TWF-27B, at a pressure of 50 kg (110 pounds). The solution was circulated for 30 minutes. The chamber was drained, and a vacuum of 13.6 kg (30 pounds) was applied and maintained for 10 minutes. Then the chamber was returned to ambient atmospheric pressure. The chamber was opened and the treated wood product was removed and placed in a rotary drying oven, where it was slowly dried for 24 hours with hot air and steam. • Example 1: TFO of 1.6 cm (5/8 pig) Injected under pressure with WOF-24 A 1.6 cm (5/8 pig) TFO analysis sample was prepared and analyzed in accordance with the procedures described above. The results of the analysis are as follows: Analyzed Material 1) Manufacturer: World Environmental Irvington, Alabama 2) Combustion Index 1 3) Average Thickness (cm) 1.4 (pig) 0.547 4) Average Weight (kg / m2) 0.1 (Ib / ft2) 2.38 ) Average Depth of N / D Slots (cm) (pig) 6) Product Description: Table of oriented fibers, 1.6 cm (5/8 pig) injected under pressure with WOF-24 Treatment Concentration: 33% of WOF- 24 7) Coffee Color 8) Surface treated on both sides 9) Selection of the sample Manufacturer 10) Selection Date 4/1996 11) Description of the Material Manufacturer by the 12) Mounting Method Self-supporting on the edges 13) Conditioning of the 22 Sample (days) Conditions and Analysis Data 1) Preheating time of 2:00 Specimen (min) 2) Temp. of Tunnel Bricks (degrees C) 40.6 (degrees F) 105 3) Ignition Time (seconds) 55 4) Time to End of 13 feet at 10:00 Tunnel or Distance to front of flame 5) Area of the Time-Distance Curve (in./m) 153.8 (min./foot) 46.9 6) Fuel and Temperature a) Fuel (m3 / min.) 0.140 (footVmin.) 4.946 b) Temp. Max. of the End of the Louver (degrees C) 360 (degrees F) 680 c) Time for the Temp. Max. (min.) 9:55 7) Subsequent Combustion No Results of the Analysis The results of the analysis, calculated based on the areas under the curves, of the distance covered by the flames, temperature, and smoke developed versus time, as shown in figures la-c, are given in the following table , for materials used in calibration, and for: Table of oriented fibers, 1.6 cm (5/8 pig) injected under pressure with WOF-24 OBSERVATIONS: There was no complete combustion. Charred and scaly surface up to 3.5 m (11-1 / 2 feet). COMMENTS: The average moisture content of the first panel was 15.2%. CONCLUSIONS: Based on the analysis, the spreading of the flames, calculated according to ASTM E-84-94, complies with Class A (Class I) -25 or under the spreading of the flames.

Example 2: Manufactured Table of Wood Particles, 1.9 cm (3/4 pig) Injected under Pressure with WOF-24 A panel analysis sample made of 1.9 cm (3/4 pig) wood particles was prepared and analyzed in accordance with the procedures described above. The results of the analysis are as follows: Analyzed Material 1) Manufacturer: World Environmental Irvington, Alabama 2) Combustion Index 1 3) Average Thickness (cm) 2.10 (pig) 0.824 4) Average Weight (kg / m2) 0.16 (lb / ft2) 3.76 ) Average Depth of Grooves (cm) N / A (pig) 6) Product Description: Table made of wood particles, 1.9 cm (3/4 pig) injected under pressure with WOF-24, TWP-27 and TWP -27B Treatment Concentration: 12% WOF-24, TWP-27 and TWP-27B 7) Coffee Color 8) Surface treated on both sides 9) Sample selection Manufacturer 10) Selection Date 4/1996 11) Description of the Material Manufacturer by part of 12) Mounting Method Self-supporting on the edges 13) Conditioning of the 22 Sample (days) Conditions and Analysis Data 1) Preheating time of 2:00 Specimen (min) 2) Temp. of Tunnel Bricks (degrees C) 40.6 (degrees F) 105 3) Ignition Time (seconds) 90 4) Time to End of 11 feet at 7:30 Tunnel or Distance to front of flame 5) area of the Time-Distance Curve (min./m) 128.6 (min./foot) 39.2 6) Fuel and Temperature a) Fuel (m3 / min.) 0.139 (footVmin.) 4.927 b) Temp. Max. of the End of the Louver (degrees C) 346 (degrees F) 655 c) Time for Temp. Max. (min.) 9:50 7) Subsequent Combustion No Results of the Analysis The results of the analysis, calculated based on the areas under the curves, of the distance covered by the flames, temperature, and smoke developed versus time, as shown in Figures 2a-c, are given in the following table , for materials used in calibration, and for: Table made of wood particles, 1.9 cm (3/4 pig) injected under pressure with WOF-24 OBSERVATIONS: There was no complete combustion.

Charred and scaly surface up to 2.9 m (9-1 / 2 ft). COMMENTS: The average moisture content of the first panel was 16.7%. CONCLUSIONS: Based on the analysis, the spreading of the flames, calculated according to ASTM E-84-94, complies with Class A (Class I) -25 or under the spreading of the flames.

Example 3: Oregon Pine Plywood, 1.6 cm (5/8 pig) Injected under Pressure with WOF-24 An Oregon pine plywood analysis sample, 1.6 cm (5/8 pig), was prepared and analyzed in accordance with the procedures described above. The results of the analysis are as follows: Analyzed Material 1) Manufacturer: World Environmental Irvington, Alabama 2) Combustion Index 1 3) Average Thickness (cm) 1.56 (pig) 0.616 4) Average Weight (kg / m2) 0.10 (lb / ft2) 2.37 5) Average Depth of Slots ( cm) N / A (pig) 6) Product Description: Oregon pine plywood, 1.6 cm (5/8 pig) injected under pressure with WO-24 Treatment Concentration: 33% of WOF-24 7) Coffee Color 8) Surface treated on both sides 9) Selection of the sample Manufacturer 10) Selection Date 4/1996 11) Description of the Material Manufacturer by the 12) Mounting Method Self-supporting on the edges 13) Conditioning of the 22 Sample (days) Conditions and Analysis Data 1) Preheating time of 2:00 Specimen (min) 2) Temp. of the Tunnel Bricks (degrees C) 39.4 (degrees F) 103 3) Ignition Time (seconds) 65 4) Time to the End of 13-1 / 2 feet at 9:30 Tunnel or Distance to the front of the flame 5) Area of the Time-Distance Curve (min./m) 179.4 (min./foot) 54.7 6) Fuel and Temperature a) Fuel (m3 / min.) 0.139 (ft3 / min.) 4.933 b) Temp. Max. from the End of the Louver (degrees C) 354 (degrees F) 670 c) Time for Temp. Max. (min.) 8:05 7) Subsequent Combustion No Results of the Analysis The results of the analysis, calculated based on the areas under the curves, of the distance covered by the flames, temperature, and smoke developed versus time, as shown in Figures 3a-c, are given in the following table , for materials used in calibration, and for: Oregon Pine Plywood, 1.6 cm (5/8 pig) injected with pressure with WOF-24 OBSERVATIONS: There was no complete combustion.

Carbonized and scaly surface up to 3.66 m (12 feet). COMMENTS: The average moisture content of the first panel was 14.1%. CONCLUSIONS: Based on the analysis, the spreading of the flames, calculated according to ASTM E-84-94, complies with Class B (Class II) -75 or under the spreading of the flames.

The primary objective of the present invention is satisfied by the present invention. Prior to the present inventive method, there were no commercially convenient methods to adequately treat sawn, green wood, which conserved sawn wood and converted sawn wood into a product resistant to fire, moisture and insects. Therefore, the present invention is superior for two reasons. First, it provides a method and composition for the complete penetration of sawnwood, green or other wood products having a high water content, as well as providing a superior method and composition for treating dried or manufactured wood products. Second, the use of a preservative that penetrates sawn wood, green, is commercially advantageous. Prior art injection methods require that the wood products are dry before treatment. Therefore, to adequately inject pressure, a wood product, the product has to be dried, treated with a preservative and re-dried. By contrast, wood products prepared in accordance with the present invention do not need to be dried before treatment, eliminating the drying step and therefore reducing process costs, labor costs and the use of energy. The above invention has been described with reference to the preferred embodiment. Modifications and obvious alterations will occur to other people when reading and understanding the preceding detailed description. It is intended that the invention includes those modifications and alterations as far as they are within the scope of the api or equivalent indications thereof. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (24)

RE IVIND ICAC IONE S

1. A method for converting wood products, fire-resistant products, putrefaction and insects, characterized in that it comprises the step of injecting pressure of these wood products with an aqueous solution consisting essentially of a silicate, a wetting agent and a Rheology modifier, where the pH of the aqueous solution is at least 9.0.

2. The method for converting wood products, in fire resistant products, to putrefaction and insects, in accordance with what was claimed in claim 1, characterized in that the aqueous solution also includes borax.

3. The method according to what was claimed in the rei indication 1, characterized in that the aqueous solution also includes a safe bactericide or fungicide from the environmental point of view.

4. The method to convert wood products, in products resistant to fire, putrefaction and insects, in accordance with what was claimed in. Claim 1, characterized in that the pressure injection step includes the steps of: a. place wooden products in a pressure vessel; b. contact the wood products with the aqueous solution; c. increase the pressure in the pressure vessel; d. drain the aqueous solution from the pressure vessel; and. reduce the pressure in the pressure vessel; and f. Dry the wood products.

5. The method for converting wood products, fire-resistant products, putrefaction and insects, in accordance with what was claimed in claim 1, characterized in that the wood product is sawn wood, green.

6. The method for converting wood products, fire-resistant products, putrefaction and insects, in accordance with what was claimed in rei indication 3, characterized in that it also includes the step of applying a vacuum to wood products, immediately before the step of contact with the solution.

7. The method for converting wood products, in products resistant to fire, putrefaction and insects, in accordance with what was claimed in rei indication 3, characterized in that in the step of increasing the pressure, the pressure increases of 18.2 kg to 72.7 kg (40 to 160 pounds) for an interval of 20 to 90 minutes.

8. The method for converting wood products, in products resistant to fire, putrefaction and insects, in accordance with what was claimed in claim 6, characterized in that the wood products consist of a board made of wood particles, density agglomerate medium and fiber oriented table, and the pressure is increased to approximately 18.2 kg (40 pounds).

9. The method for converting wood products, in products resistant to fire, putrefaction and insects, in accordance with what was claimed in claim 6, characterized in that the wood products consist of one between a product of natural wood and sawn wood , green, and the pressure increases to approximately 63.6 kg (140 pounds).

10. The method for converting wood products, in products resistant to fire, putrefaction and insects, in accordance with what was claimed in rei indication 1, characterized in that the pH of the solution is approximately 11.2 to 1.4.

11. The method for converting wood products, fire-resistant products, putrefaction and insects, in accordance with what was claimed in rei indication 1, characterized in that the aqueous solution includes a suitable colorant.

12. The method for converting wood products, fire-resistant products, putrefaction and insects, in accordance with what was claimed in rei indication 1, characterized in that the aqueous solution includes from 18 to 60% sodium silicate, 0.01 to 2% wetting agent and 0.01 to 2% of a rheology and water modifier.

13. The method for converting wood products, in products resistant to fire, putrefaction and insects, in accordance with what was claimed in rei indication 1, characterized in that the aqueous solution consists essentially of approximately 38% sodium silicate, about 0.1% wetting agent and about 0.1% rheology modifying agent, and the solution has about 21% solids.

14. The method for converting wood products, in fire resistant products, to putrefaction and insects, in accordance with what was claimed in claim 13, because the solution consists of an aqueous solution of 38% sodium silicate, 0.1 % wetting agent and 0.1% rheology modifying agent, and the solution has 21% solids.

15. The method for converting wood products, in fire-resistant products, to putrefaction and insects, in accordance with what was claimed in claim 13, characterized in that the solution also includes 1 to 10% borax.

16. A solution for converting wood products, in products resistant to fire, putrefaction and insects, characterized in that it consists essentially of a silicate and one between a wetting agent and a rheology modifier, where the pH of the solution is minus 9.0

17. The solution according to what was claimed in the rei indication 16, characterized in that it also includes a safe bactericide or fungicide from the environmental point of view.

18. The solution according to that claimed in claim 16, characterized in that the pH of the solution is approximately 11.2 to 1.4.

19. The solution for converting wood products, fire resistant products, putrefaction and insects, in accordance with what was claimed in rei indication 16, characterized in that the solution also comprises borax.

20. The solution to convert wood products, fire-resistant products, putrefaction and insects, in accordance with what was claimed in claim 16, characterized in that it includes from 18 to 60% of sodium silicate, from 0.01 to 2% of wetting agent and 0.01 to 2% rheology modifying agent.

21. The solution for converting wood products, fire-resistant products, putrefaction and insects, in accordance with what was claimed in claim 20, characterized in that the aqueous solution also comprises 1 to 10% borax.

22. A wood product injected under pressure, characterized in that it is prepared by pressure injection of the wood product, in accordance with the method of claim 1.

23. The wood product injected under pressure, according to claim 22, characterized in that the aqueous solution includes from 18 to 60 of sodium silicate and one between an amount of 0.1 to 2 of wetting agent, from 0.1 to 2 of modifying agent of rheology and 1 to 10% of borax.

24. The wood product injected under pressure, in accordance with what was claimed in claim 22, characterized in that the aqueous solution also includes one between a bactericide or fungicide, safe from the environmental point of view, and borax.