JP3384417B2 - Wood treatment agent - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to woods, that is, wood,
The present invention relates to a wood treating agent (hereinafter referred to as "wood treating agent") that can improve various properties of wood by impregnating or applying it to a material such as bamboo or rattan without impairing the wood texture. is there.

[0002]

2. Description of the Related Art Wood is widely used as a material for building materials and crafts for the purpose of improving various properties such as water resistance, fire resistance, decay resistance, dimensional stability and abrasion resistance. It has been practiced to impregnate or apply various high molecular weight compounds, low molecular weight compounds, agents such as preservatives, or treating agents such as inorganic substances to the class.

Among them, the method of using an inorganic substance such as barium phosphate or water glass is known as a method which has a very high flame retarding effect on wood and can improve various properties of wood such as breaking strength and dimensional stability. ing. However, since this method is a method of filling the cell lumen of wood with an inorganic substance, in order to obtain a sufficient effect, it is necessary to inject a large amount of chemical with a weight increase rate of 100% or more after treatment with respect to the weight of wood. However, there is a problem that the treated wood becomes heavy along with the high cost, and the original advantages of the wood such as workability and heat insulation are lost.

To solve these problems, the sol-gel method using a silicon alkoxide is applied to wood to produce a silicone polymer in the cells of the wood, so that the original soft wood texture of the wood is not impaired and the flame retardancy is improved. And a method for improving various properties such as water resistance have been disclosed (Japanese Patent Laid-Open Publication No. Sho 6-62).
3-265601).

However, among the silicon alkoxides listed here, those containing a hydrophobic and bulky alkyl group in the molecule have poor impregnability into wood and low reactivity, so hydrochloric acid, organometallic compounds, etc. There is no choice but to adopt the method of accelerating the curing with the above catalyst. Since the polymerization and hardening of silicon alkoxide using a catalyst occurs mainly in the cell lumen rather than in the cell wall of wood, it is necessary to fill the cell lumen of wood with a curing agent for the treatment in order to obtain a sufficient wood modifying effect. As a result, the weight increase rate with respect to the weight of wood is 160-
It would be necessary to inject as much as 185% of the drug.
This makes the treated wood heavier as well as costly,
There was a drawback that workability and heat insulation were also deteriorated.

The above-mentioned published patent also discloses partial hydrolysis products of tetraalkoxysilanes containing no alkyl group. Even if it is not as much as the above-mentioned silicon alkoxide containing a large amount of alkyl groups, the reactivity and impregnability are low in this case as well, and a catalyst is required, and a large amount of a drug must be injected. there were. Furthermore, the treated wood is hard and brittle, and it is easy to have many film defects that allow moisture and live bacteria to invade. There was a drawback.

[0007]

SUMMARY OF THE INVENTION In view of such a current situation, the present invention provides woods with excellent modifying effects such as water resistance, flame retardancy, dimensional stability, decay resistance and abrasion resistance at low cost. It is intended to provide a wood treatment agent which can be applied by a simple method.

[0008]

As a result of earnest studies on the above problems, the present inventor found that the general formula H _n --Si (OR)
_4-n [wherein, R is an alkyl group having 1 to 4 carbon atoms, and a plurality of R in one molecule may be the same or different. n is 1
Or 2. ] The prepolymer obtained by causing a partial hydrolysis / condensation reaction of the alkoxysilane represented by] has a high hydrolysis reactivity, and when used in the treatment of wood, the water content and the OH group inside the wood The present invention was found to be able to easily undergo hydrolysis / condensation reaction to cure, and to impart excellent modifying effects such as water resistance, flame retardancy, dimensional stability, decay resistance and abrasion resistance to wood. Has been completed.

In the present invention, R is an alkyl group having 1 to 4 carbon atoms, specifically, methyl, ethyl, propyl,
Examples thereof include isopropyl, n-butyl, i-butyl, t-butyl and the like. There are two or three R in one molecule,
These may be the same or different types. As the carbon number of R is smaller, the hydrolysis reaction is more likely to occur. Therefore, the hydrolysis / condensation reaction proceeds faster when reacted with woods, and the hydrolysis reaction is less likely to occur in the case of bulky material such as t-butyl. However, while it takes time to react with woods, there is a tendency that, for example, the stability when a wood treatment agent is emulsified into water is increased.

As the partial hydrolysis-condensation reaction product, a single alkoxysilane may be used, or two or more kinds may be used. The polymer chain of the partially hydrolyzed condensation reaction product can be branched or linear, and either of them can be used as a wood treating agent.

The preferred carbon number of R is that the larger the carbon number of R, the slower the reaction with woods,
An alkyl group having 1 to 3 carbon atoms is preferable, but R is preferable because the reaction is fast and the reaction by-product is harmless ethanol.
Is particularly preferably ethyl. In the case of n = 2, the preferable number of n is that the monomer before partial hydrolysis is chemically unstable and industrially difficult to handle. Hydrolysis condensation products are preferred. Therefore, the wood treating agent of the present invention is particularly preferably one composed of a partial hydrolysis-condensation reaction product of triethoxysilane.

Alkoxysilanes, which are the raw materials for the wood treating agent of the present invention, can be industrially produced at low cost, and partial hydrolysis-condensation reaction products can be easily produced from the alkoxysilanes under appropriate conditions. Because you can get
The wood treating agent of the present invention is industrially easily and inexpensively obtained.

The average degree of polymerization of the partially hydrolyzed condensation reaction product is
Dimers to 100-mers are preferable. The higher the degree of polymerization, the smaller the flammability of the reaction product and the faster the curing in wood. However, if it is too large, the impregnability into wood tends to deteriorate because the viscosity increases. Therefore, when the impregnation property into woods is required, dimers to decamers are preferably used, and more preferably dimers to pentamers. When importance is attached to shortening of drying time and work safety rather than impregnation property, a pentamer to a 100-mer is preferably used, and a 10-mer to a 50-mer is more preferable.

The partially hydrolyzed condensation reaction product of the alkoxysilane can be used alone as a wood treating agent, or can be used by mixing it with an organic solvent such as toluene, hexane or isopropanol at an arbitrary ratio. it can.
In addition, since a stable emulsion is formed with an aqueous solvent by using an appropriate emulsifier or pH adjuster,
It is also possible to use a water-based wood treatment agent.

The concentration of the partially hydrolyzed condensation reaction product of the alkoxysilane in the wood treating agent varies greatly depending on the type of solvent and the impregnation method, but is generally 1 to 100% by weight, preferably about 10 to 100% by weight. Is. Further, the wood treatment agent of the present invention may be mixed with dyes, pigments, chemicals, fillers, etc., if necessary.

As the woods capable of improving the above-mentioned various properties by the wood treating agent of the present invention, various kinds of trees such as hardwoods and conifers, bamboo, rattan and the like can be used. Further, it can be sufficiently used for woods subjected to other chemical treatment such as resin impregnation, and can also be used as a pretreatment for the chemical treatment.

The wood treating agent of the present invention is used by coating or impregnating wood. The method for impregnating wood is, for example, dipping in wood at room temperature and normal pressure, but impregnation under reduced pressure and addition. Pressure impregnation, a known chemical injection method for woods, or the like, or the treatment agent may be impregnated with steam. When applying, spray, coater, brush etc. on the surface of wood,
Well-known means can be used. The partial hydrolysis-condensation reaction product of an alkoxysilane has extremely high permeability to woods, and can be easily permeated into the interior of wood by any method.

Further, it is a characteristic of the wood treating agent that a large effect can be obtained with a small amount of impregnation when the wood treating agent is impregnated with the wood treating agent. It is difficult to specify a preferable amount of impregnation because it largely changes depending on the degree of dryness. However, when the weight increase rate of the treated wood with respect to the weight of the untreated wood is 0.1% or more, a clear wood-modifying effect is exhibited. And, even with a relatively small weight gain rate of 1 to 40%, the treating agent of the present invention can reach a satisfactory modifying effect. Since the treatment agent has a good impregnating property, further 4
It is easy to obtain a weight increase rate of 0% to 150% or more, and at this time, the modifying effect of wood gradually increases to the maximum level. That is, the wood treatment agent of the present invention is effective in the range of 0.1 to 150% or more in the weight increase rate after the treatment of woods, but considering that the treated woods become heavy and the cost of the chemicals, etc., It is preferably used in the range of 0.1% to 40%, more preferably 1% to 40%.

It is sufficient for the wood treatment agent of the present invention to apply or impregnate the wood material with it and leave it at room temperature.
By heating, the chemical change of the treatment agent can be promoted and the treatment time can be shortened. The higher the temperature in the case of heating, the faster the reaction proceeds, and the cured product of the treating agent is further baked to improve the modifying effect, but if it is too high, discoloration or deterioration of the wood itself may occur, and therefore it is preferable. The temperature is from 20 to 400 ° C, more preferably from 40 to 200 ° C.

Since the wood treating agent of the present invention has a high reactivity inside the wood, it can complete the treatment of wood without adding a hydrolysis catalyst as in the prior art. It is also possible to accelerate the curing by adding the above, preliminarily impregnating the wood with the catalyst, or by causing the treating agent to act and then allowing the catalyst to act. Examples of the catalyst include inorganic acids such as hydrochloric acid and phosphoric acid, formic acid,
Organic acids such as acetic acid and p-toluenesulfonic acid, and organometallic compounds such as dibutyltin dilaurylate, lead naphthenate, zirconocene chloride and titanocene chloride,
Aminosilanes, amines, amine salts, etc. may be mentioned, and these may be used alone or in admixture of two or more.

Further, when the wood treating agent contains a solvent component, the removal of the solvent and the evaporation of the alcohol by-produced by the curing reaction of the treating agent are sufficient even if left at room temperature. By doing so, the drying time after the treatment can be shortened. Since the wood treating agent of the present invention is thermally stable after the curing reaction is completed, the heating temperature during drying can be freely set as long as the quality of the wood itself is not deteriorated, and a method of reducing the pressure to accelerate the drying Is also possible.

[0022]

Although the mechanism of action of the wood treatment agent of the present invention is not clear, it is highly impregnable and reactive with wood, the point that an effect can be obtained with a small amount of the treatment agent, and the texture of wood after treatment. It is presumed that features such as beauty and beauty retention are obtained by the following actions.

That is, the alkoxysilane partial hydrolysis-condensation reaction product contained in the wood treating agent of the present invention is excellent in impregnation property, so that it rapidly impregnates inside and around the cell walls of woods. Furthermore, since it has a Si—H bond in the molecule, it has high chemical reactivity and reacts quickly with water and OH groups in woods. Since the cell lumen is not filled with the cured product of the treatment agent, a sufficient effect can be obtained with a small amount of the treatment agent. Furthermore, since most of the Si—H bonds remain in the molecule after the reaction, the cured product has a SiO network structure that forms a network structure with only 2 to 3 of the four Si bonds.

When a conventional tetraalkoxysilane is used, a rigid SiO network in which all four Si bonds are bonded to each other is a rigid SiO network, which is hard and brittle due to lack of freedom in bonding, and water and raw materials. There are many membrane defects that allow bacteria to infiltrate, and the number of pieces that adhere to the surface of wood can be innumerable cracked by the strain during curing, so they solidify into sand and spoil the appearance. On the other hand, since the SiO network composed of 2 to 3 bonds by the wood treating agent of the present invention has flexibility in bonding, it is highly flexible, and is waterproof, antibacterial, and fireproof in the cell wall. It produces a defect-free film that produces high effects such as properties, and even the amount of the film attached to the surface of wood becomes a colorless and transparent extremely thin film without impairing the aesthetic appearance of the wood surface.

[0025]

EXAMPLES Hereinafter, the wood treatment agent of the present invention will be described more specifically with reference to Examples and Comparative Examples. Example 1 50 g of water was added to 1000 g of triethoxysilane, and the mixture was stirred to obtain a partial hydrolysis-condensation product of triethoxysilane having an average degree of polymerization of 2.3. A 50 wt% acetone solution was used as the wood treatment agent of Example 1.

Length 30 mm × width 30 mm × length 100
After immersing 3 mm 2-way Masatogi cedar sapwood in a wood treatment agent at room temperature and atmospheric pressure for 10 minutes, dry it at room temperature for 24 hours, and
Individual test pieces were obtained. The weight increase rate after the treatment with respect to the weight of the wood before the treatment was 12.1% on the average of the three test pieces. The following water absorption test was performed on these test pieces. That is, a mixture of paraffin and petrolatum was applied while leaving one of the mouths of the test pieces to be waterproof, and submerged in water having a depth of 5 cm so that the fiber direction was parallel to the water surface.
After a lapse of time, it was taken out and the water absorption was measured by the following calculation formula (1), and the average value of three test pieces was used as a representative value. The results are shown in Table 1.

[0027]   Calculation formula (1) Water absorption rate = (W−Wo) / Wo × 100 (%) Wo; weight of test piece before immersion in water (g) W: Weight of test piece immediately after completion of immersion in water (g)

Comparative Example 1 As in Example 1, the same water absorption test as in Example 1 was carried out using three untreated cedar sapwood of the same size as test pieces. The results are shown in Table 1.

Comparative Example 2 1 part of a 0.4% by weight hydrochloric acid aqueous solution was added to 10 parts by weight of a 50% by weight acetone solution of a tetraethoxysilane partial hydrolysis product (trade name "ethyl silicate 40", manufactured by Colcoat Co., Ltd.). 3 parts of the cedar wood having the same dimensions as in Example 1 were treated in the same manner as in Example 1 using the treatment liquid which was stirred for 2 hours at room temperature and then left for 12 hours. The weight increase rate after the treatment with respect to the weight of the untreated wood was 6.6% on average among the three test pieces. The same water absorption test as in Example 1 was carried out, and the results are shown in Table 1.

To the methyltrimethoxysilane monomer,
To 10 parts by weight of a 50% by weight acetone solution of a methyltrimethoxysilane dimer prepared by adding 0.5 molar equivalent of water,
1 part by weight of a 0.4 wt% hydrochloric acid aqueous solution was added, and the mixture was stirred at room temperature for 2 hours and then left standing for 12 hours.
Three cedar pieces having the same size as the above were treated in the same manner as in Example 1. The weight increase rate after the treatment with respect to the weight of the untreated wood was 8.3% on average among the three test pieces. Example 1
The same water absorption test as above was conducted, and the results are shown in Table 1.

[0031]

[Table 1]

Since the wood treating agent of the present invention has a high impregnating property with respect to wood, a sufficient impregnation amount can be obtained only by impregnating wood at room temperature and atmospheric pressure, and the hydrolysis reaction inside the wood is also possible. Since the property is also high, it was possible to obtain a sufficient weight increase rate after the treatment even without a catalyst. In Comparative Examples 2 and 3, even though hydrochloric acid was used as a hydrolysis catalyst, the impregnation amount was smaller than that in Example 1 due to poor impregnation of the chemical.

The results of the water absorption test show that the wood treated with the treating agent of the present invention has the most excellent water resistance. The appearance of the wood after treating and drying each of these test pieces was exactly the same as that before treatment in Example 1 and Comparative Example, and no change in appearance due to the treatment was observed, but in Comparative Example 2 It was confirmed that white powder adhered to a part of the treated wood surface. In Comparative Example 3,
The color of the treated wood was slightly different from that before the treatment, as if it had absorbed oil.

Example 2 Using the same wood treating agent as in Example 1 at room temperature and atmospheric pressure for 10 minutes, using 3 pieces of 2-way Masako cedar sapwood having a length of 30 mm x width 30 mm x length 5 mm, the temperature was measured. When dried at 120 ° C. for 4 hours, the weight increase rate after the treatment with respect to the weight of the untreated wood was 12.3% on the average of the three test pieces.
After measuring the length of this test piece in the radial direction with respect to the annual ring, it was stored at a temperature of 40 ° C. and a relative humidity of 90% for 24 hours, and the length was measured again. In addition, in order to calculate the ASE value, the same moisture absorption test was performed using three untreated cedar wood pieces of the same size as test pieces, and the ASE value was calculated from the measurement result using the following formula (2). The results are shown in Table 2.

The definition of the ASE value is represented by the calculation formula (2). Calculation formula (2) ASE = (Sc−St) / Sc × 100 (%) Sc; Volume swelling rate of untreated material (%) St; Volume swelling rate of treated material (%)

Comparative Example 4 Using the same treatment liquid as in Comparative Example 2, the moisture absorption test described in Example 2 was carried out on each of three test pieces treated in the same manner as in Example 2. In addition, the weight increase rate after the treatment with respect to the weight of the untreated wood in Comparative Example 4 was 13.4% on the average of the three test pieces. In addition to this, in order to calculate the ASE value, the same moisture absorption test was performed using three untreated cedar wood pieces having the same size as test pieces, and the ASE value was calculated from the measurement results.
The results are shown in Table 2.

Comparative Example 5 Using the same treatment liquid as in Comparative Example 3, the moisture absorption test described in Example 2 was carried out on each of three test pieces treated in the same manner as in Example 2. In addition, the weight increase rate after the treatment with respect to the weight of the untreated wood of Comparative Example 5 was 11.4% on the average of the three test pieces. In addition to this, in order to calculate the ASE value, the same moisture absorption test was performed using three untreated cedar wood pieces having the same size as test pieces, and the ASE value was calculated from the measurement results. The results are shown in Table 2.

[0038]

[Table 2]

In these tests, wood test pieces, which are generally called wood mouth test pieces and in which the chemical solution permeates from the wood mouth very easily, were used. Therefore, there is no difference in impregnating property between Example 2 and Comparative Examples 4 and 5. Not so much. In addition, since the hydrolysis catalyst was used in each comparative example with respect to the treating agent of Example 2 which is highly reactive even without a catalyst, the weight increase rates after treatment were almost the same.

However, dimensional stability after moisture absorption (ASE value)
Then, Example 2 showed higher dimensional stability. The reason for this is that even if the weight increase rate after the treatment is the same as that of the example, in Comparative examples 4 and 5, since the curing was carried out forcibly by the hydrolysis catalyst, it was of a low quality with no effect on hygroscopicity and dimensional stability. This is probably because a cured film was formed.

[0041]

Industrial Applicability The wood treatment agent of the present invention contains a partial hydrolysis-condensation product of an alkoxysilane having hydrogen and an alkoxyl group, has a good impregnation property for woods, and easily undergoes a hydrolysis reaction inside wood. It is possible to impart to woods an excellent modifying effect such as flame retardancy, dimensional stability, decay resistance and abrasion resistance.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B27K 3/34

Claims (2)

(57) [Claims] 1. The formula H _n —Si (OR) _{4 −n} [where R
Is an alkyl group having 1 to 4 carbon atoms, and a plurality of R in one molecule may be the same or different. n is 1 or 2. ] The processing agent of the woods containing the partial hydrolysis-condensation reaction product of the alkoxysilane represented by these. 2. A formula H-Si (OR) ₃ [wherein R is an alkyl group having 1 to 4 carbon atoms, and a plurality of R in one molecule may be the same or different. ] A treatment agent for woods, which comprises a partial hydrolysis-condensation reaction product of trialkoxysilane represented by the following formula and having an average degree of polymerization of a dimer to a 50mer.