BRPI0703783B1 - wood quality improvement process - Google Patents

Abstract

wood quality improvement process. The present invention relates to a process for imparting to softwoods the qualities of noble woods by a process of inserting polymeric or onomeric material into the interstices and vacancies presented therein by the noble woods. Taken together, the process of the present invention comprises the phases of pre-extraction of water by vacuum, lyophilization for drying and fixation of the structure, still in the same environment of lyophilization, addition of monomer or ionomers, catalyst and eventual additives and application. controlled pressure and ultrasonic agitation to facilitate the penetration of the substances into the micropores generated by the water outlet in the lyophilization process, which preserves the microstructural characteristics of the wood and the subsequent polymerization by y-ray irradiation (gamma) . After that, the wood must rest for a minimum of 72 hours as per astm standards.

Description

(54) Title: PROCESS TO IMPROVE WOOD QUALITY (73) Holder: LUIS ERNESTO ROCA BRUNO, Engineer, architect and the like. CGC / CPF: 05006956879. Address: RUA ANTONIO FREDERICO OZANAN, 370, São Carlos, SP, BRAZIL (BR), 13575-290, Boliviana; ROSA MARIA MAZZUCATO, Social worker and domestic economist. CGC / CPF: 76014100806. Address: TRAVESSA ANA AUGUSTA, 96, Barretos, SP, BRAZIL (BR), 14781-559, Brazilian (72) Inventor: NICOLA BLOISE.

Validity Term: 10 (ten) years from 11/27/2018, subject to legal conditions

Issued on: 11/27/2018

Digitally signed by:

Alexandre Gomes Ciancio

Substitute Director of Patents, Computer Programs and Topographies of Integrated Circuits

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WOOD QUALITY IMPROVEMENT PROCESS

Field of the Invention

The present invention relates to a process to give the so-called soft woods the qualities of noble woods, by means of a process of inserting polymeric or ionomeric material into the interstices and vacancies presented inside the non-noble woods.

Fundamentals of the Invention

Wood is widely used in engineering due to its

resistance-to-weight characteristics. Socially, the feature of renewability, ease of processing, possibilities of obtaining pieces of large dimensions that can be folded into pieces of compatible dimensions for different applications, easy connections and splices, satisfactory natural conditions of thermal insulation and sound absorption and competitive cost in relation to others materials, such as metals and cements, are very convenient.

It is of fundamental importance, for the proper use of wood, the knowledge of its properties and structure. As it is a heterogeneous organism, made up of cells arranged and organized in different directions, its aspect varies according to the observed face. In addition to appearance,

the physical-mechanical behavior of wood also differs in each of the main directions, a phenomenon known as anisotropy.

Wood is made up of millions of individual units, called cells. They are connected to each other through a cementing substance, the middle lamella. Two layers make up the wall of a cell: the primary wall, a thin outer layer, and the secondary wall (a thicker inner layer made up of three other layers). The main constituents of the cell wall are cellulose, poliosis or hemicellulose and lignin. Cellulose is a linear polysaccharide of high molecular weight, consisting of a single type of sugar unit. It is the main component of plant cell walls.

The term polioses refers to a mixture of low molecular weight polysaccharide polymers, which are closely associated with cellulose

2/8 in the cell walls (mainly in the primary wall) and in the middle lamella (traces).

Another fundamental constituent of wood is lignin. It is located mainly on the middle lamella during the lignification of plant tissue. When the lignification process is completed, it usually coincides with the death of the cell, which will participate in the formation of the heartwood that constitutes the structural part of a trunk, that is, the part with the most advantageous mechanical properties. Lignin, like cellulose, is also a polymer, but it differs from this in that it is predominantly an aromatic compound and highly irregular 10 in its constitution and molecular structure.

In addition to structural components such as cellulose, polioses and lignin, wood also has inclusions of organic and inorganic materials, with low and high molecular weights. These can be extracted through water, organic solvents or by volatilization. It is the extracts, which 15 include tannins, oils, gums, resins, dyes, salts of organic acids, aromatic compounds, deposited predominantly in the heartwood, which give it a more accentuated coloring.

A living tree absorbs water and mineral salts from the soil, which circulate throughout the plant until they reach the leaves, constituting the raw sap. O

The reverse process, that is, from the leaves to the roots, is done by the elaborated sap, which consists basically of water and products elaborated in photosynthesis.

In this way, the wood of live or recently felled trees has a high moisture content. Under these conditions, the vessels and channels of the wood, as well as the lumen of its cells, are saturated with water. In the same way, the interstices located inside the cell walls can also be saturated. Inside the wood you can find: (A) capillary water (free water), located inside the vessels, meatus, channels and lumen of the cells; (B) adhesion or hygroscopic water (trapped water), located on cell walls.

When all free water or capillarity is removed from the wood, with only the adhesion water remaining, it is said that the wood has reached the fiber saturation point (PSF). Normally the PSF is between 22 and

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30% humidity, varying from species to species. From the PSF there are important changes in the structure of the wood, such as: contractions that can cause defects such as warping, cracks and changes in their mechanical strength. In addition, susceptibility to fungi and insects attacks, 5 somehow restrict a more intense use of this raw material.

Nowadays, Brazil has vast reserves of tropical species. However, the selective and predatory exploitation of native forests has caused a reduction in the supply of species for established use, whose demand remains growing. As a result, several of these species, such as Aroeira, 10 Cerejeira, Freijó, among others, known as hardwoods due to their high mechanical resistance, are practically depleted in their reserves. Consequently, prices reach prohibitive levels, culminating in making the commercial use of these raw materials unfeasible.

The alternative in the search for a solution to this issue has been the use of reforestation species, in particular of the Eucalyptus and Pinus genera, called softwoods, as they have low mechanical resistance characteristics.

Data from SBS (Brazilian Forestry Society) show an increase in consumption of raw material from planted forests

for obtaining solid wood products, in relation to a tendency to decrease the consumption of wood from native forests in Brazil, starting in 1997.

Related Technique

Due to the problems mentioned above, giving characteristics of 25 hardwoods to softwoods becomes highly desirable. This can be achieved with techniques that impregnate wood with oligomers, monomers, ionomers, polymers in solution or other material that can establish a more resistant internal network, intertwined with the wood structure. This technology aims to fill the pores obtained in the wood 30 by drying, which is usually carried out in greenhouses, with a monomer or other of the substances mentioned above, and, consequently, after the process, these substances are transformed into polymer three-dimensionally.

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Processes for the insertion of polymeric material, known as impregnation, in the interstices and vacancies presented inside by non-noble woods are already known from the state of the art. Basically, the technique consists of impregnating the wood with a monomer and a catalyst and subjecting it to heating to provoke the reaction. The wood impregnated with the polymer has similar properties or, in some aspects, superior to those of noble woods.

US patent document 2007/0029279 discloses one such process in which the treatment formulation is a mixture of a first solution containing styrene and a second solution containing furfuryl alcohol. Patent document W00230638 uses a solution of furan polymer obtained from a polymerizable solution of furfural alcohol monomer containing at least furfuryl alcohol and another compound selected from maleic anhydride, phthalic anhydride, maleic acid, malic acid, phthalic acid, or combinations their.

In patent document WO0153050 the monomers: styrene, methyl styrene (particularly paramethyl styrene and terbutyl styrene) are used, alone or in combination, with the advantage of orthomethyl styrene and terbutyl styrene being highlighted by their low vapor pressure and, consequently, low emissions .

Also in Brazil, several studies using traditional wood in the

parents were published as, for example, the master's thesis by MANRICH, S. - Ό use of Brazilian wood in obtaining polymer-wood composites ”, Federal University of São Carlos, 1984, and the doctoral thesis by STOLF ORTIGOSA, D - “Influence of impregnation with styrene and methyl methacrylate on physical and mechanical properties of wood from 25 Eucalyptus Grandis and Pinus Caribaea var. ondurensis ”, University of São

Paulo, 2005. In these studies, wood impregnation has been traditionally carried out through immersion, vacuum-immersion and vacuum-pressure. As the impregnating material, styrene monomer and benzoyl peroxide, among others, are used as a catalyst. The polymerization of this substance inside the wood is achieved, in a simpler and more economical way with chemical initiators, compounds that with the rise of the temperature decompose in free radicals.

The choice of these chemical initiators defines the process temperature.

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The extraction of water from the interior of the wood, by drying by raising the temperature, causes a rearrangement of its structure and displacement of chemical compounds of low molecular weight, existing in its structural mesh, causing it to agglutinate the interstitial micropores in pores of volume. topping. These pores will be filled by the monomers during the polymerization process used in this case. That is, with a subsequent rise in temperature that further degrades the structure of lignin, facts that thus contribute to the degradation of its structural integrity.

As is evident from the reading of the documents mentioned above φ 10, in all cases the wood undergoes a heating process, which is a great disadvantage, as it is harmful to the final quality of the product, compromising the mechanical characteristics more noble sought in this treatment.

An objective of the present invention is to provide a process for impregnating and improving the quality of wood, which does not present the drawbacks mentioned above.

A second objective was to allow more uniform wood impregnation, in order to obtain a product with mechanical characteristics superior to the systems known in the art.

Summary of the Invention

Taken as a whole, the process of the present invention comprises the phases of pre-extraction of water by vacuum, freeze-drying for drying and fixing the structure, still in the same freeze-drying environment, addition of monomer or ionomers, catalyst and any additives and application of controlled pressure 25 and ultrasonic agitation to facilitate the penetration of substances in the micropores generated by the water leaving the lyophilization process, a process that preserves the micro-structural characteristics of the wood and the subsequent polymerization through γ-ray irradiation (gamma ) or X-rays.

After that, the wood must rest for a minimum of 72 hours 30 according to ASTM standards.

The basic scope of the present invention consists of a careful sequence of operations as listed below: vacuum drying, drying

6/8 interstitial by lyophilization with preservation of the wood microstructures, infiltration by immersion of monomers or ionomers by combination of controlled pressure and mechanical vibration via ultrasound, and polymerization through γ (gamma) or X-ray irradiation.

Detailed description of the invention • 10

Next, a detailed description of the invention will be presented, with its preferred realization and with some application examples.

The process object of the present invention comprises the following phases:

Vacuum pre-drying - The pre-drying process consists of submitting the wood to a continuous vacuum, at or near room temperature, so as not to compromise the stability of its structure, since the drying of the wood obtained by heating, when from water extraction, it deforms the microstructure of the wood, forcing the compounds present in the lignin and of low molecular weight to migrate to vacancies caused by the extraction. The vacuum pre-drying process allows the conservation of the structural characteristics of the wood.

Lyophilization - Consists of submitting the previously dried wood as in the previous item, to a lyophilization process with a temperature between 0 ° C and negative 50 ° C to fix the structural system of the wood and complete dehydration of the same without affecting its structure or displacements of its volatile and non-volatile components. Once the structure of the wood is fixed in the freeze-drying environment, only the water molecule is extracted from the interior of the wood, preserving the micropores created, in the original positions that the extraction of the water molecule gave rise to.

Impregnation - It consists of adding, after the procedure, in the same environment as the lyophilization, in the absence of oxygen, the styrene monomer with benzoyl peroxide as a catalyst for the polymerization under suitable temperature conditions, or ionomers accompanied by their additives under the appropriate conditions. This step allows the contact of the wood with the compounds that will be part of its structure.

Ultrasonic treatment - consists of submitting the dipped wood

1)

2)

3)

4)

7/8 in the monomeric or ionomeric substance, with its additives, in the same environment, at an appropriate pressure and with an ultrasonic stirring to facilitate the penetration of monomeric or ionomeric substances with their own additives, in vacancies and interstices present inside the wood, 5 accentuated by the drying and freeze drying process.

5) Polymerization by irradiation - It consists of submitting the wood so impregnated with the styrene monomer and benzoyl peroxide or ionomers with their additives, to the polymerization process through γ (gamma) or X-ray irradiation. The time of exposure to gamma radiation 10 from Co ⁶⁰ or X-rays depends on the volume of the wood to be irradiated and the process takes place at or near room temperature, and in conditions of perfect shielding from radiation escape. The wood samples will be packed in sealed polyethylene packages in an inert atmosphere so that the wood is preserved from contamination 15 during the irradiation process.

6) Stabilization - Its purpose is to let the treated wood rest for at least

minimum 72 hours for quality testing and characterization. The rest stage is necessary for the complete stabilization of the wood and the exhaustion of the polymerization process. After this rest, the parts, prepared according to the appropriate ASTM standards, to perform tests will be submitted to them.

The geometry of the parts to be treated depends on the use for which they are intended, because once impregnated and after the polymerization process, any forming process would modify and damage the structure.

A great advantage of the present invention comprises the preservation of the micro-structural characteristics of the wood, avoiding the drawbacks of the prior art, caused by the heating used in the drying and polymerization steps. According to the present invention, these drawbacks are overcome, since the perfect impregnation of the monomers is guaranteed by the combination of controlled pressure and mechanical vibration via ultrasound, culminating in the elimination of the

8/8 heating polymerization, replaced by polymerization through γ (gamma) or X-ray irradiation.

Although the “impregnation process for improving the quality of wood”, which has just been described in relation to the examples presented, 5 is presented as the preferred embodiment of the invention, it will be understood that several modifications may be introduced by specialists in matter without departing from the scope of its protection, and some of these elements can be replaced by others with the same technical function, especially the materials used, their dimensions, shapes and proportions.

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Claims (6)

1. PROCESS TO IMPROVE WOOD QUALITY, characterized by comprising the following phases: 1) submit the wood to a continuous vacuum pre-drying, for water extraction; 2) to subject the previously dried wood to a freeze-drying process with a temperature between 0 ° C and minus 50 ° C, for complete dehydration and fixation of its structure; 3) add, after the previous procedure, in the same lyophilization environment and in the absence of oxygen, the monomer as a catalyst for polymerization or ionomers and any additives; 4) to subject the wood dipped in the polymerization additives to an appropriate pressure and an ultrasonic stirring, to facilitate the penetration of the substances in the micropores generated by the exit of the water in the lyophilization process; 5) subject the wood so impregnated to a polymerization process through γ (gamma) or X-ray irradiation; and 6) leave the wood to rest for a minimum of 72 hours for its complete stabilization and completion of the polymerization process. 2. WOOD QUALITY IMPROVEMENT PROCESS, according to claim 1, characterized by conserving the microstructural characteristics of the wood. 3. WOOD QUALITY IMPROVEMENT PROCESS, according to claim 1, characterized in that the polymerization additives are the styrene monomer with benzoyl peroxide as a catalyst or ionomers accompanied by their additives. Petition 870180011744, of 02/09/2018, p. 8/8