FI71512C - COMPOSITION FOR MODIFIERING AV VIRKE. - Google Patents

Description

The present invention relates generally to the woodworking industry and, more particularly, to a wood modification composition.

The wood modified with the composition proposed here can be used in a corrosive environment, for example, as a building material for cooling towers, ventilation ducts, mineral fertilizer storage facilities, livestock buildings and other construction and construction sites, , in the mechanical engineering and mechanical industries, as a substitute for ferrous and non-ferrous metals, in the manufacture of parquet and 15 skis and similar industries, as a substitute for harder hardwoods, in the manufacture of sports equipment, in particular as a decorative surface and finishing material for souvenirs, etc.

Last but not least, interest in wood modification 20 has grown significantly with the significant reduction in wood yield in many countries and the desire to improve the durability of wood products, especially in conditions of high ambient temperature and high humidity. In general, in order to diversify the use of wood-based materials, increase the use of softer leaf-25 wood species, and expand the use of wood in various industries, one line has been to modify wood with synthetic resins and monomers added in liquid form and then cured by heat and chemical reagents.

A large number of wood modification compositions based on polymerizable and polycondensable resins are known. These compositions are known to significantly improve the physical and mechanical properties of the natural starting material. The wood material modified in this way is almost completely converted into a multicomponent composition consisting of a thermosetting synthetic polymer and native high molecular weight compounds. In long-term use, the properties of such a system depend primarily on oxygen without air.

2 71512 oxidative cleavage caused by variations in ambient humidity and ambient temperature, mainly on synthetic polymers. Thus, the reduction or elimination of oxidative cleavage of polymers during use is of paramount importance.

A wood modification composition is known in the art (cf. SU-inventor's certificate 321 366, Int. Cl. B 27K 3/34), which consists of a phenol-furfural-formaldehyde resin, an acid catalyst and an organic solvent. The wood is impregnated with said composition in an autoclave by a vacuum pressing method. The impregnated wood is then heat treated in drying chambers to form a solid thermosetting resin of phenol-furfural-formaldehyde resin cured by an acid catalyst and elevated temperature. Under the conditions of use, the usefulness of wood modified with a polymer based on phenol-furfu-15 ral-formaldehyde resin is limited because the polymer degrades with varying ambient temperature and humidity.

Fluctuations in ambient temperature and humidity cause the cleavage of hydrogen bridges in the modified polymer and also the cleavage of hydrogen bridges between the polymer and the wood complex.

In addition, as the ambient state and humidity vary, oxidative cleavage occurs in the wood complex itself, generating free radicals.

All of the above causes a deterioration in the physical and mechanical properties of the modified wood material, thus shortening its service life.

The object of the present invention was to provide a wood modification composition which makes it possible to stabilize various decomposing processes caused by varying ambient temperature and humidity. This object is achieved by a composition comprising a phenol-furfural-formaldehyde resin, a catalyst and an organic solvent and further comprising a stabilizer according to the invention.

The invention is characterized in that the wood modification composition further comprises a phenol-furfural-formaldehyde resin, a catalyst and an organic solvent.

3,71512

The stabilizer chemically binds the reactive nuclei generated by the oxidative cleavage of the polymer, preventing the cleavage processes from continuing. As a result, the physical and mechanical properties 5 of the modified wood are maintained at varying ambient temperatures and humidity.

The addition amount of the stabilizer of less than 0.5% by weight is not able to effectively stabilize the properties of the modified wood during use. The content of said stabilizer Liu-10 in the modifying composition determines the upper limit of its concentration to be 1.5% by weight.

The preferred stabilizer is ferrocene.

When added to a wood modification composition, the highly reactive ferrocene simultaneously participates in the reactions through both the ion-15 mechanism and the free radical mechanism, thus preventing oxidative cleavage leading to aging of the modified wood and maintaining the properties of the natural material during use.

Such a wood modifying composition is characterized by a viscosity that allows uniform saturation of the wood.

Also suitable in the proposed wood modification composition is monoacetylferrocene.

Monoacetylferrocene participates in the reactions through both the ionic mechanism and the free radical mechanism and reacts with the phenol-furfural-formaldehyde resin to give a compound of formula

/ TT \ OH H OH

30 \ wy ~ CH ~ CH ^ 1 A.

xy ^ ° -rn— f —rVH2 ° H + H2o Ö Ό0 · 35 4 71512 Such a compound has been found to protect against oxidative cleavage caused by variations in ambient temperature and humidity.

It is also recommended that the stabilizer be a mixture of ferrocene 5 and monoacetylferrocene.

Such a stabilizer allows a modified wood to be characterized by the stability of its properties at varying ambient temperatures and humidity.

The following detailed description clarifies the practice of the present invention.

An acid catalyst, for example benzenesulphonic acid, is added in an amount of 0.8-1.5% by weight to an organic solvent, for example acetone, in which 5-25% by weight of phenol-furfural-formaldehyde resin is dissolved. The resulting solution is stirred thoroughly and then ferrocene, monoacetylferrocene or a mixture of ferrocene and monoacetylferrocene is added with stirring in an amount of 0.5 to 1.5% by weight. The viscosity of the formed system is then measured with a viscometer B3-4 with a range of 12.0-12.5 s.

As the resulting composition hardens, ketal and semiketal type compounds are formed. This reaction takes place in both acidic and basic media due to the electron-seeking groups attached to the carbonyl group in the α-position. The condensation forms polymeric compounds containing attached ferrocene or monoacetyl-ferrocene molecules, which in turn inhibit cleavage processes and thus the aging process of the modified wood under the conditions of use.

Wood modified with the composition proposed herein was tested by an accelerated aging method performed as follows. The modified wood was kept immersed in water for three days at 19-23 ° C and then dried for four days, drying for 8 hours at 105-107 ° C for each day and the remaining 16 hours at 15-23 ° C.

The test values obtained showed that the proposed wood modification composition is very stable. The reduction in compressive strength after 24 pressing cycles in the direction of the fibers was li 5,71512 with 25.5% wood modified with a known composition based on phenol-furfural-formaldehyde resin and 14.6% with natural starting material. For wood modified with the proposed composition based on phenol-furfural formaldehyde resin to which ferrocene had been added, the reduction in compressive strength was 9.7%, and when the additive was monoacetyl-ferrocene, this value was 9.5%.

The weight loss of wood modified with the present composition was reduced by about 30% in the aging test.

Thus, the proposed wood modification composition makes it possible to improve the stabilizing effect of the modifying polymer contained in the wood 2.6-fold.

The following examples further illustrate the invention.

Example 1 15

0.8% by weight of benzenesulfonic acid as catalyst was added to acetone in which 72.0% by weight of phenol-furfural-formaldehyde resin was dissolved. The resulting solution was stirred thoroughly and thus 0.5% by weight of ferrocene was added continuously with stirring.

The viscosity of the formed impregnation system measured with viscometer B3-4 was 12.3 s.

Example 2

0.8% by weight of benzenesulfonic acid as a catalyst was added to an organic solvent in which 84.0% by weight of phenol-furfural-formaldehyde resin was dissolved. The resulting solution was stirred thoroughly, and then 1.0% by weight of ferrocene was added to the solution with stirring.

The viscosity of the formed impregnation system measured with a viscometer B3-4 was 12.45 s.

Example 3

1.5% by weight of benzenesulfonic acid as a catalyst was added to an organic solvent in which 35.0% by weight of phenol-furfural-formaldehyde resin was dissolved. The solution thus obtained was stirred thoroughly, and then 1.5% by weight of monoacetylferrocene was added to the solution with stirring.

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The viscosity of the impregnation system formed, measured with a viscometer B3-4, was 12.27 s.

Example 6 0.8% by weight of benzenesulfonic acid as a catalyst was added to acetone in which 84.0% by weight of phenol-furfural-formaldehyde resin had been dissolved, and the solution thus obtained was then mixed thoroughly, and 1.0% by weight was added to the solution with constant stirring. monoasetyyliferroseeniä.

The viscosity of the impregnation system thus obtained, measured with a viscometer B3-4, was 12.15 s.

Example 7

1.5% by weight of benzenesulfonic acid as a catalyst in an organic solvent in which 72.0% by weight of phenol-furfural-formaldehyde resin had been dissolved was added with thorough stirring, and then a mixture of 0.5% by weight of ferrocene and monoacetylferrocene in a ratio of 1 : 1.

The viscosity of the impregnation system thus obtained, measured with a viscometer B3-4, was 12.35 s.

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Example 8

1.5% by weight of benzenesulfonic acid as a catalyst was added with thorough stirring to an organic solvent in which 84.0% by weight of phenol-furfural-maldehyde resin was dissolved, and then 1.0% by weight of a mixture of ferrocene and monoacetylferrocene was added to the solution with stirring. 1: 1. The viscosity of the impregnation system thus obtained, measured with a viscometer B3-4, was 12.42 s.

The viscosity of the impregnation system thus obtained, measured with a viscometer B3-4, was 12.42 s.

Example 9

1.5% by weight of benzenesulfonic acid as catalyst was added with constant stirring to an organic solvent in which 94.0% by weight of phenol-furfural-formaldehyde resin was dissolved. A 1: 1 mixture of 1.5% by weight of ferrocene and monoacetylferrocene was then added to the solution with stirring.

Il 7 71512

The viscosity of the impregnation system formed, measured with a viscometer B3-4, was 12.47 s.

An advantage of the present invention is that with the proposed composition the service life of the modified wood is extended, which prolongs the service life of the modified wood with the periodic maintenance of the wood structures, which in connection with the periodic maintenance of the wood structures means lower wood consumption and reduced repair work.

In describing the various embodiments of the present invention in the above examples, special terminology has been used to a limited extent for clarity. It is to be understood, however, that the present invention is in no way limited to the terminology used herein, and that each term used encompasses equivalents that relate to the same functions and can be used to solve the same problems.

Although the present invention has been described herein by means of preferred, typical embodiments, it will be apparent to those skilled in the art that minor changes may be made to the wood modification composition of the present invention. All such changes and deviations are considered to be in accordance with the spirit and scope of the invention as defined in the appended claims.