FI72456C - Impregnation composition for thermochemical modification of wood and its fabrication process. - Google Patents

Description

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The present invention relates to a thermochemical modification of a wood material used in the manufacture of ski edges and a lower layer, as well as in other articles requiring improved wood physicochemical properties and weathering. More particularly, the present invention relates to an impregnation mixture for thermochemical modification of wood and a process for its preparation.

The modern chemical industry makes available a wide range of monomeric, oligomeric and polymeric products, which, depending on the end use, make it possible to improve the physical-mechanical properties, bio-water and chemical resistance of wood as well as other properties.

The weather resistance of wood is improved by adding 20 small amounts of some phenols and other toxic compounds. For example, in U.S. Patent No. 3,955,077 to Haper AB, polychlorophenols, nitrophenol, chloronaphthalene as well as zinc oxide, bu-25-tin, copper compounds in petroleum-based solvents and the like have been used as antiseptics. "Desowaq-Bauer Holzchuts" Company DE Patent No. 2,555,984) proposes polyphenols in connection with quinolines and thiophosphoric acid ester compounds; "Andersen Corp." (U.S. Patent No. 4,103,804) modifies mixtures of polychlorophenols with polyesters of polyhydric alcohols and paraffin waxes; The company "A / S Cheminowa" (GB Patent No. 1,528,041) proposes the use of MeSC> 2N (Ph) -SC12CC12F, wherein Me is a metal, as an antifungal preservative; Koppers Com (U.S. Patent No. 35,399,752) proposes the use of early methyl cyanide; "Basf AG" (DE Patent No. 2,622,028) proposes preparations based on boric acid 2 72456 and alkylene oxides to prevent the harmful effect of insects on wood; Albright and Wilson Ltd proposes solutions of organotin compounds and quaternary ammonium base 5 (GB Patent No. 1,467,420). SU inventor's certificates Nos. 537,814 and 571,376 relate to mixtures containing CuO and rosin in turpentine or CuSO 4, Na 2 Cr 2 O 3 and H 3 B 3 in acetic acid.

Over the past two to three decades, attempts by 10 researchers focused on improving the properties of poor quality wood by impregnating them with synthetic resins, including monomers and oligomers, followed by their polycondensation using thermochemical methods.

For example, in U.S. Patent No. 4,194,033, the treatment of poorly supported wood is performed with an alkylamine; In JA Patent Application No. 53-30764, the treatment further involves the use of an aqueous solution of formaldehyde. In order to absorb the free formaldehyde in the wood, an additional boric acid is added to the solution (cf. JA Patent Application No. 80-117611).

In the SNTL, phenolic alcohols (cf. SU Inventor's Certificate No. 404,620) and several modifications thereof have been successfully used as the impregnation mixture, e.g.

25% solution of maleic anhydride (SU inventor certificate No. 620373), condensation products of a mixture of ethylene and higher fatty alcohols (SU inventor certificate No. 536,044), urea-formaldehyde resin (SU inventor certificate No. 575,218).

JA Patent Applications Nos. 49-35401, 52-79004, 49-43126, PL Patent No. 41878 relate to the successful use of low molecular weight polycondensation products of phenol and formaldehyde. For adsorption of formaldehyde as an odor, it has been proposed to treat wood with solutions containing sodium sulfite and ammonium salt (cf. JA Patent Application No. 49-43126).

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A disadvantage of modifying wood with phenolic alcohols and phenol-formaldehyde oligomers is the uneven impregnation, corrugation and cracking of the wood, the instability of the impregnation mixture.

5 Therefore, impregnation and subsequent curing of the impregnation mixture should be carried out under pressure and gradually drying the temperature from 30-45 ° to 100-120 ° C, but curing should take place at 160-180 ° C (cf. JA- Patent Application 10 No. 49-20483). This curing temperature results in deteriorated properties of the modified wood.

An impregnation mixture containing methylol derivatives of urea, formaldehyde and a polymerization initiator is also known in the art (cf. DE patent No. 2,063,171). JA Patent Application No. 52-24082 relates to a impregnation mixture containing phenol, dihydroxybenzene and melamine or urea in addition to a salt to ensure fire resistance. The wood is treated in a two-step process; after evaporation of the solvent at 160 ° C, the wood is treated with formaldehyde while the mixture hardens.

To improve the mechanical strength properties of wood modified with a phenolic, urea, melamine, or urea melamine-formaldehyde resin-based impregnation mixture, JA Patent Application No. 52-24082 describes the addition of cellulose derivatives to a monomer starting mixture.

A prior art mixture most similar to the present invention in terms of subject selection and results obtained is the impregnation mixture of U.S. Patent No. 3,832,251 containing monomeric resorcinols and a formaldehyde dimethylol urea source in aqueous ethanol.

This impregnation mixture is prepared by mixing the monomeric resorcinols with an aqueous-ethanolic solution of dimethylol urea.

The 4,72456 impregnation solution described above in U.S. Patent No. 3,832,251 has its positive properties with the exception of certain disadvantages such as: 1. Due to the presence of up to 2% free formaldehyde in the impregnation mixture and therefore the formation and use of dimethylol urea in modified wood. based on the equilibrium of the disintegration reaction, there are health and hygiene difficulties present when using the mixture and further in the further processing of the ski blanks.

2. The poor stability of the impregnation mixture prevents the drying temperature from being raised above 50 ° C and the preparation of a mixture with a dry matter content of more than 30% (50% dry matter content is obtained only when the mixture is prepared in small quantities).

3. Due to the poor stability of the aqueous-ethanol solution of dimethylol urea, the latter is prepared directly on site, making it impossible to perform centralized preparation of the impregnation mixture.

4. The brittleness of wood modified with this impregnation mixture prevents its mechanical treatment during the manufacture of the edge of the ski and the 20 lower layers.

It is an object of the present invention to overcome the above disadvantages.

The present invention is directed to the preparation of an impregnation mixture for thermochemical modification of wood which does not contain any free formaldehyde, is very stable and allows the final drying temperature of impregnated wood blanks to be raised and has a high dry matter content, which allows the wood to be modified. 30 and thus improves the conditions for further mechanical treatment.

This object is achieved by an impregnation mixture for thermochemical modification of wood containing monomeric resorcinols and bound formaldehyde in an aqueous-alcoholic solution containing ethanol; according to the present invention, the impregnation mixture

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Water-soluble total phenols having a hydroxy group content of 12.0 to 13.3 meq / g as monomeric resorcinols, urea, hexamethylenetetramine and molecular complexes of these phenols with urea and hexamethylene-5 tetramine at equilibrium; it also contains ethylene glycol, its homology or glycerol; the composition of the impregnation mixture is as follows, parts by weight: water-soluble shale oil phenols 100 urea 28-36 10 formaldehyde 35-40 ammonia 13-15 ethylene glycol, its homogene or glycerol 3-10 ethanol 5-1750 water 100-3370 15 Impregnation mixture according to the present invention - the dry matter content is in the range from 3 to 60% by weight. This is an advantage of the mixture and results in an improvement in the physico-chemical properties of the modified wood. It is not desirable to use a impregnation mixture having a dry matter-20 content of less than 3% by weight because the mixture lacks the ability to modify. At a dry matter content of more than 60% by weight, the modification does not improve due to a sharp increase in viscosity.

The improvement of all the properties of the impregnation mixture (no free formaldehyde at all, good stability and high dry matter content) is mainly achieved by the impregnation mixture being a system containing molecular complexes of water-soluble shale oil phenols in equilibrium 6 72456

NH NH

/ 1, _ ^ ^ 2

M ... O = C + (CH) N__. M ... (CH) N + O = C

\ 2 6 4 'vT 2 6 4 x.

NH2 nh2 / fx / lx 5 NH „^ / 2 M + 0 = C M + (CH„) CN, \ z 0 4 nh2

OH

M- t ^ jLoH, R = - “~ CH3 '-C2H3' -C2H5 '-C3H7'

Rn n = 15

It should be noted that the required activity under curing conditions is achieved by using as reactant the highly reactive water-soluble total shale oil phenols having a hydroxy group content of 12.0 to 20 13.3 meq / v. The term "water-soluble shale oil phenols" means a product obtained by heat treatment of Estonian oil shale.

During the heat treatment of the combustible shale, part of the phenol (2-2.5% by weight of the calculated shale oil) is recovered with the tar water, while the other part is obtained by further washing the shale oil with water. These waters with a phenol content of about 10 g / l are subjected to extraction with organic solvents to give water-soluble total phenols of the rock slate which boil at a temperature in the range from 240 to 360 ° C. These phenols contain about 10% by weight of monohydric and 90% by weight of dihydric phenols. It has been found that dihydric phenols are alkyl resorcinols.

Studies in recent years have made it possible to determine the chemical composition of the water-soluble total phenols of shale oil, which is shown in Table 1 below.

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table 1

Chemical composition content, weight% ______ 5 _1_2__ monohydric phenols 8.6-10.4 resorcinol 1.6-2.3 2- and 4-methylresorcinols 2.6-3.1 5-methylresorcinol 28.0-30.3 2,4-Dimethylresorcinol 0.7-0.8 4,6-Dimethylresorcinol 1.1-1.5 2.5-Dimethylresorcinol 5.8-6.4 5-Ethylresorcinol 10.2-10.7 2-ethyl-5 -methylresorcinol 1,7-1,8 4,5-dimethylresorcinol 5,7-7,5 5-ethenylresorcinol 1,3-1,7 2-methyl-5-ethylresorcinol 1,9-2,0 2,4.5- trimethylresorcinol 2.1-3.0 5-propylresorcinol 1.9-2.7 20 4-methyl-5-ethylresorcinol 1.1-1.5 including other alkyl resorcinols 18.4-22.6: four basic components 50-55 5-Substituted alkyl resorcinols 60-68 25 hydroxy group content 12.0-13.3 meq / g.

As can be seen from the table above, the main components are 5-methyl, 5-ethyl, 2,5-dimethyl and 4,5-dimethyl resorcinols, the total amount of which varies within narrow limits (50-55% by weight), of the above figure 28 -30% by weight of 5-methylresorcinol.

A special feature of water-soluble crude shale oil phenols is their high reactivity compared to re-35 sorsinol. This is explained by the presence of 5-substituted alkyl resorcinols in the mixture of total phenols of the above shale oil.

...............- - ΤΊ ~. . - 8 72456

The final drying temperature of impregnated wood blanks can be raised to 90 ° C due to the increased stability of the impregnation mixture of the present invention.

An increase in the dry matter content of the impregnation mixture to 60% by weight is achieved due to the fact that the molecular complex mixture included in the equilibrated solution maintains homogeneity even at low solvent levels, i.e. in an aqueous-alcoholic solution (a mixture of ethanol 10 with ethylene glycol, its homologue or glycerol in water).

The improved flexibility of the modified wood is achieved by the polycondensation reaction of hexamethylenetetramine-15 with the water-soluble total phenols and urea of the shale oil under the drying and pressing conditions of the impregnated wood, thus leading to the formation of ammonia, which together with high boiling alcohol (ethylene).

Improved health and hygienic conditions when modifying wood are achieved due to the fact that the impregnation composition of the present invention does not contain any free formaldehyde.

The increased dry matter content of the impregnation mixture as well as the increase in the final drying temperature of the impregnated wood blanks make it possible to increase the productivity of the modification and wood drying processes, respectively.

The present invention also relates to a process for preparing a impregnation mixture for thermochemical modification of wood, wherein the mixture of water-soluble total phenols of shale oil having a hydroxy group content of 12.0-13 meq / g, urea, polyhydric alcohol - ethylene glycol, its homologue or glycerol, ethanol and water, heated to a temperature in the range of 60-95 ° C so that the components are present in the mixture in the following proportions, parts by weight: 9 72456 total water-soluble phenols of shale oil 100 urea 28-36 ethylene glycol, its homologue or glycerol 3-10 ethanol 6 -1025 5 water 3-1492 to give an aqueous-alcoholic solution containing the above-mentioned water-soluble total phenols of shale oil, urea and a molecular complex of these phenols with urea; 37% aqueous formaldehyde solution, 24% aqueous ammonia solution, ethanol and water in the following proportions of components are also mixed together, parts by weight: 37% aqueous formaldehyde solution 95-107 24% aqueous ammonia solution 54-62 15 ethanol 1-725 water 1-1764 and this mixture is maintained at a temperature in the range of 20-60 ° C to give an aqueous-alcoholic solution of hexamethylenetetramine; a previously prepared aqueous-alcoholic solution containing 20 water-soluble total phenols of shale oil, urea and the molecular complex of these phenols with urea is mixed with the above-mentioned aqueous-alcoholic solution of hexamethylenetetramine in a weight ratio of 1: 1. Mixing the two aqueous-alcoholic solutions results in a saturation mixture containing an equilibrium aqueous-alcoholic solution containing total water-soluble phenols of shale oil having a hydroxy group content of 12.0-1.3 meq / g, urea, hexamethylenetetramine and said phenols. molecular complexes with urea and hexame-30 ethylene tetramine.

In the preparation of an aqueous-alcoholic solution (hereinafter referred to as Solution A) containing shale oil total water-soluble phenols, urea and the above-mentioned phenolic molecular complex with urea, it is necessary to keep the components (phenols and urea) together in the solvent at 60-95 ° C .

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In the preparation of an aqueous-ethanolic solution of hexamethylenetetramine (hereinafter referred to as solution B), it is necessary that the temperature does not exceed 60 ° C due to the volatility of the starting components (formaldehyde and ammonia).

A weight ratio of 1: 1 of the two mixed aqueous-ethanol solutions has been chosen in view of the simplicity of the method for preparing the impregnation mixture. However, it is also possible to prepare the mixture in other proportions by complicating method 10.

Aqueous B aqueous solutions A and B have an unlimited storage time and can be prepared on a centralized basis. All this makes it possible to avoid the inaccurate synthesis of dimethyl-15 loliurea (a source of formaldehyde) for the woodworking industry and to arrange the centralized preparation of the impregnation mixture.

The impregnation mixture for thermochemical modification of wood is prepared by a mechanochemical method comprising three steps; 1. Aqueous alcohol solution A is prepared in a reactor equipped with a stirrer, a thermometer, a condenser and a cooling heating jacket. The total water-soluble phenols of shale oil are added to the reactor at a hydroxy group concentration of 12.0-13.3 meq / g and the mixture is heated to 40 ° C, urea is added and the temperature is raised to 60-95 ° C, then stirred until water-soluble shale oil phenols and urea molecular complex, and polyhydric alcohol-ethylene glycol, its homologue (diethylene glycol, triethylene glycol) or glycerol, water and ethanol are added.

The solution is stirred, cooled and the vessel emptied. The shelf life of the solution is unlimited and its preparation can be performed in a centralized manner.

Aqueous alcohol solution B is prepared in a similar reactor to which a 37% aqueous formaldehyde solution is added. With constant stirring and cooling, add

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11 72456 reactor 24% aqueous ammonia solution at such a rate that the temperature of the mixture does not exceed 60 ° C. The solution is cooled and the vessel is emptied. The solution has an unlimited shelf life and can be prepared in a centralized manner.

3. The resulting aqueous-alcoholic solutions A and B are mixed in a weight ratio of 1: 1 at a temperature in the range of 20-30 ° C for 15-30 minutes until the equilibrium of the molecular complexes is reached in the impregnation solution.

The impregnation mixture thus prepared has a storage time of 20 days at a temperature of 20-25 ° C; the mixture does not contain free formaldehyde.

The process for preparing an impregnation mixture according to the present invention is further described in Table 2 in Examples 1-5 below.

Table 3 shows various uses of the impregnation mixture prepared according to Examples 1 to 5 of Table 2 according to the present invention.

Table 4 shows comparisons of the features of the impregnation composition of the present invention and the impregnation composition of the prior art U.S. Patent No. 3,832,251.

Table 2 Starting example Example 1 Example 2 Example 3 Example 4 Example 5 2 5 nents weight weight weight weight weight weight _parts_parts_parts_parts_parts_

Vesialkoholi-

solution A

Water-soluble shale oil phenols 100 100 100 100 100

Urea 36 28 32 30 32

Ethylene glycol - - 10 5

Diethylene glycol - - 10

Triethylene glycol - 10 35 Glycerol 3 -

Ethanol 6 54 93 205 1025

Water 6 3 40 285 1492 12 72456

Table 2 (continued)

Output example Example 1 Example 2 Example 3 Example 4 Example 5 nents weight weight weight weight weight weight _parts_parts_parts_parts_parts_

5 Water-alcohol solution B

37% aqueous formaldehyde solution 95 105 107 100 107 24% aqueous airanoic acid solution 54 60 62 58 62

Ethanol I 26 66 125 725

Water I 2 20 291 1764

Impregnation mixture Water-alcohol solution A 100 100 100 100 100

Aqueous-alcoholic solution B 100 100 100 100 100

Table 3 20 Chemical Example 1 Example 2 Example 3 Example 4 Example 5 composition dry matter dry matter dry matter dry matter dry matter concentration concentration concentration concentration concentration 60% by weight 45% by weight 30% by weight -% 15% by weight 3% by weight _ parts by weight parts by weight parts by weight parts by weight parts by weight

Water soluble shale oil phenols 100 100 100 100 100

Urea 36 28 32 30 32

Formaldehyde 35 39 40 37 40

Ammonia 13 14.5 15 14 15 30 Ethylene glycol - - 10 5

Diethylene glycol - - - - 10

Triethylene glycol - 10 - - 35 Glycerol 3

Ethanol 5 80 160 380 1750

Water_100_126_174_683 3370 13 72456

Table 4

Features of U.S. Patent No. 3,832,251 Impregnation Mixture Impregnation Mixture

Free formaldehyde content, weight% 1.5-2 not at all

Dry matter content 10% by weight 5-50 3-60

The storage time of the impregnation mixture is at 25 ° C day 10-12 18-20 15 Drying temperature of preforms made of impregnated wood, ° C 20-50 20-90

From storage- Impregnation mixture- Water-alcoholic solution- 20- The components of the bridge A and B are prepared with a shelf-life that is practically limited to the place of use; the preparation of the impregnation mixture is carried out in a centralized manner

Thermochemical modification of wood by the impregnation mixture of this invention includes impregnation of wood in an open bath or autoclave under pressure in a vacuum. The impregnated wood is then dried at a temperature of 20-90 ° C, ensuring that the used mixture is polycondensed in advance. The polycondensation process is carried out at 100 to 180 ° C, preferably at 100 to 120 ° C at a pressure of 0.2 to 6.0 MPa.

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The comparative physico-mechanical properties of the modified wood produced using the impregnation compositions of the present invention and the composition of the known U.S. Patent No. 3,832,251 are shown in Table 5 below.

It can be seen from Table 5 that at the same dry matter content in the impregnation mixture, the physical and mechanical characteristics of wood modified with the impregnation mixture of the present invention are 1.1-1.7 times greater than those of wood modified with the impregnation mixture of U.S. Patent No. 3,832,251.

Table 5

Impregnation Mixture Properties_Insaturation Mixture_15 of the Present Invention of Physical Mechanism No. 3832251 of Modified Wood 15 Dry matter content,% by weight 30 60 45 30 3

Example Example Example Example

_12 3_5

Compression in the direction of the fibers, MPa 133.5 171.5 167.0 145.8 122.5 20

Static bending, MPa 120.0 206.6 217.4 170.0 115.0

Adhesive joint shear stress, MPa 11.0 19.7 15.7 13.5 9.8

Impact bending 25 J / cm3 4.5 4.5 5.0 5.0 4.8

Dimensional stability,% 7.5 3.0 3.3 4.5 9.0

Density, g / cm -1 0.75 0.96 0.86 0.78 0.68

Claims (2)

7 2456 Impregnation composition for thermochemical modification of wood containing monomeric resorcinols and bound formaldehyde in an aqueous alcoholic solution containing ethanol, characterized in that the impregnation mixture contains shale oil with water-soluble total phenols having a hydroxy group content of as a monomeric resorcinol, urea, hexamethylenetetramine-10 and molecular complexes of said phenols and urea and hexamethylene-tetramine at equilibrium and that it also contains ethylene glycol, its homology or glycerol 28, the chemical composition of the impregnation mixture being as follows: -36 formaldehyde 35-40 ammonia 13-15 ethylene glycol, its homologue or glycerol 3-10 20 ethanol 5-1750 water 100-3370 Process for preparing a impregnation composition according to claim 1, characterized in that, on the one hand, a mixture consisting of total water-soluble phenols of shale oil having a hydroxy group content of 12.0-13.3 meq / g, urea, a polyhydric alcohol is heated. is ethylene glycol, its homologue or glycerol, from ethanol and water, at a temperature of 60-95 ° C, the proportions of all components being included in this mixture 30 by weight: total water-soluble phenols of shale oil 100 urea 28-36 ethylene glycol, its homologue or glycerol 3-10 ethanol 6- 1025 35 water 1-1492 to give an aqueous-alcoholic solution containing said water-soluble total phenols of shale oil, 72456 16 urea and a molecular complex of said phenols with urea; on the other hand, a 37% aqueous formaldehyde solution, a 24% aqueous ammonia solution, ethanol and water are also mixed together, the components being included in the mixture in the following parts by weight: 37% aqueous formaldehyde solution 95-107 24% aqueous ammonia solution 54-62 ethanol 1-725 water 1 On the other hand, this mixture is maintained at a temperature of 20 to 60 ° C to give an aqueous-alcoholic solution of hexamethylenetetramine; and, on the other hand, mixing an aqueous-alcoholic solution containing total phenols of shale oil, urea, and a molecular complex of these phenols and urea with an aqueous-alcoholic solution of hexamethylenetetramine in a weight ratio of 1: 1. 17 72456