JPS5920445B2 - Wood treatment method and composition therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the treatment of wood to enhance its properties, and in particular to a method of impregnating wood with resin, optionally with various additives such as preservatives and fire retardants.

It is already known that wood expands and contracts according to the degree of swelling of its cell walls.

The degree of cell wall swelling of wood depends on the type of solvent or solvent vapor acting on it and its affinity for this solvent or solvent vapor.

That is, the action of water or steam causes a high degree of swelling, and the action of less polar solvents or solvent mixtures, such as ethanol/xylene mixtures, causes dehydration and shrinkage of the cell wall.

Furthermore, when the wood cell wall, which is mainly composed of cell chains, is swollen, the porosity becomes maximum, that is, the free space of the amount of cellular silver is expanded, and if the wood cell wall is not swollen, the porosity is extremely low.

Therefore, the size and amount of molecules that can be deposited within the wood cell wall depends on the degree of swelling of the cell wall.

The above-mentioned properties of wood have been utilized in various ways to impart specific properties to wood.

That is, a water-soluble polyglycol, such as polyethylene glycol having a molecular weight of about 3000 to 6000, can be introduced into the wet or swollen wood cell walls.

[Forest Products Journal
Products Journal) 9 (1959
): 3.107-110 of A. J. Stam's paper "A Novel Method for Dimensionally Stabilizing Wood" and Mann Society Technology, A Journal of Industrial.・Arts Education (ManSociety Tech
nology, A Journal ofIndu
trial Arts Education) 3
3 (1): Barry, C., Leslie, September/October 1973, 13-16.
eslie)'s paper ``PEG of the Woodworker's Heart''
ker's Heart)".

] Such polyglycols have a low vapor pressure and, unlike water, evaporate extremely slowly.

Therefore, the above treatment is very effective in preventing wood from turning and cracking.

Such treatments are often used to treat, for example, wood carvings so that they have a long service life even when stored in a dry atmosphere.

However, the polyglycols remain water-soluble and leach out when the treated wood is left in wet conditions.

The usefulness of this treatment method is therefore extremely limited.

Based on a somewhat similar idea, the use of water-soluble low molecular weight phenolic and urea-based resins in wood treatment is also known.

(See U.S. Pat. Nos. 3,968,276, 3,519,476 and 3,193,117.

) In order to fix these resins within the wood cell walls, heat treatment is required to harden the phenolic resin and make it non-water soluble.

A combination of heat and pressure is often used to densify the wood.

Although effective, such treatments require specialized equipment and are therefore of practical use only in the industrial production of specialized products requiring water or chemical resistance or structural strength or a combination of these. Ru.

Many other polymers are used to impregnate wood.

For example, acrylic monomer (US Pat. No. 3,663,261)
Polyisocyanate (U.S. Pat. No. 3,539,386)
), dibromopropylglycidyl ether (US Pat. No. 3,483,021), and the like.

All of these treatments require a secondary treatment after soaking, in which the monomers are fixed in the wood by polymerization.

This secondary treatment is often a heat treatment of the wood after soaking, but in the case of vinyl monomers such as acrylic resins, it is also possible to use gamma ray irradiation.

The need for secondary treatment after impregnation leads to high costs and is also complicated.

Therefore, there are no processing methods of this type that are widely used in practice.

Even when the wood cell wall is wet or swollen, only molecules of relatively small size can penetrate the narrow chest wall.

The molecular size that penetrates the cell wall depends on the degree of swelling and the type of wood.

Polymers with large molecular sizes cannot penetrate even the swollen wood cell walls.

For example, polyvinyl acetate and polyacrylate emulsions have recently been used to produce adhesives and paints for wood.

Unlike condensation polymers such as the phenolic resins mentioned above, this emulsion is produced by free radical or chain polymerization and has a low content of low molecular weight components.

(1966 Interscience Publishers (I)
published by Terscience Publishers),
F.W. Bill Meyer Jr.
Meyer, Jr.) “Text.

Book of Polymer Science (TextBoo
"k of Polymer 5science)".

) Therefore, when wood is treated with this emulsion, the cell walls of the wood become swollen due to the presence of water, but the polymer molecules are too large to penetrate even the swollen cell walls.

The wood is thus provided with a protective coating but not with properties such as roll and crack resistance.

This is why the use of aqueous polymers with large molecular sizes is not effective in achieving the objectives of the present invention.

Although low molecular weight vinyl resins such as acrylic resins are known, it is not known that they can be used to treat wood cell walls to improve rolling resistance, dimensional stability, and the like.

Resins of this type have been proposed as leveling agents for addition to floor polishes, for example.

Alkyd resins are condensation polymers and contain large amounts of low molecular weight components (see "Text Book of Polymer Science" above).

In addition, alkyd resins are cross-linked and cured by reaction with air.

That is, it becomes solvent resistant and partially insoluble.

Previously, alkyd resins soluble in organic solvents were the only standard commercial products.

The organic solvent contained in this alkyd resin does not swell the wood cell walls.

Many of them shrink wood cell walls by removing water and reducing the porosity of the wood.

Over the past decade or so, alkyd resins soluble in water or water/polar solvent mixtures have become widely used as overcoats, such as paint materials for washing machines, refrigerators, automobiles, etc.

However, this type of alkyd resin is the basis for imparting coating and crack resistance, dimensional stability, permanent fire protection and rot protection to wood without the need for post-impregnation secondary treatments such as heating or gamma irradiation. That was not recognized.

They can be cross-linked to form polymers simply by exposure to air.

Also, because it is aqueous and contains sufficient amounts of small but reactive molecules, it has excellent permeability through wood cell walls.

In a preferred embodiment, the present invention permanently deposits a particular chemical mixture within the cell walls of the wood fibers, by making the chemicals to be deposited pre-soluble in water or a water-miscible solvent complex. It swells the cell walls of the wood, allowing maximum penetration of chemicals through the cell walls themselves.

Chemicals have a small molecular size that allows at least one component of the mixture to enter the free space within the cell wall in the presence of a solvent, and are capable of reacting at room temperature and with the aid of the presence of other chemicals that act either self-cuttingly or as catalysts. It can be converted to a water-insoluble form under atmospheric pressure, simultaneously blocking other water-soluble chemicals in the mixture so that the entire mixture can be leached later when the wood is treated with water or an aqueous solution. The selection consists of molecules that can completely prevent or significantly reduce the effects of

A water-reducible alkyd resin or a water-reducible modified alkyd resin can be chosen as the wood treatment chemical convertible to a water-insoluble form for use in the present invention.

Long, medium or short oil/water dilutable alkyd resins currently commercially available from a number of manufacturers and known to those skilled in the art of industrial coatings are illustrative of this type of alkyd resin.

Modified alkyd resins, such as urethane modified alkyd resins, are also commercially available and known to those skilled in the art.

Generally such alkyd resins or modified alkyd resins are soluble in water or water/polar solvent mixtures in the form of slightly neutral or slightly alkaline solutions.

As examples of polar solvents, mention may be made of butanol or higher alcohols, ketones, 2-butoxyethanol, butyl calpitol, propazole, N-methyl pyrrolidone.

It is known that alkyd resins are formed by combining synthetic dibasic acids such as phthalic anhydride, isophthalic anhydride, trimellitic anhydride with synthetic or natural fatty oils, ie, glycerides of fatty acids.

The fatty acids or glycerides used generally contain mixtures of fatty acids differing in chain length and degree of chain unsaturation.

Alkyd resins can be further modified by coupling with various glycols.

A widely used glycol is pentaerythritol diethyl glycol.

The properties of alkyd resins can be significantly altered by cross-linking, for example by the addition of incyanates such as toluene and diincyanates.

Such alkyd resins are called urethane-modified alkyd resins.

Urethane modified alkyd resins dry to a much harder finish than unmodified alkyd resins.

Other examples of modified alkyd resins include those modified by reacting with natural resins such as rosin, synthetic resins such as phenolic resins, amine resins, silicone resins, or by reacting with imides, styrene, etc. .

The final molecular weight or degree of polymerization of the alkyd resin is controlled by adding the appropriate amount of one of the reactants, ie fatty acids or glycols.

Therefore, the final product alkyd resin generally contains small amounts of unreacted hydroxyl groups or acidic groups, or both.

Alkyd resins prepared with a relatively low ratio of synthetic polybasic acid to fatty acid are long-oil alkyd resins, those prepared with a high ratio are short-oil alkyd resins, and those prepared with a medium ratio are called long-oil alkyd resins. It is called a neutral alkyd resin.

The alkyd resins mentioned above are soluble in aromatic hydrocarbon solvents and aliphatic hydrocarbon solvents, but are generally insoluble in polar solvents such as water, methanol, and butanol.

Recently, attempts have been made to increase the solubility of alkyd resins in polar solvents by reacting them with various chemicals.

This can be achieved by incorporating highly polar groups into the alkyd structure.

For example, an alkyd resin may be prepared using excess acid such that the final product has about 10 to 100 acid groups, preferably about 20 to 60 acid groups.

The acidic atomic groups are then partially or completely neutralized using amines, ammonia, or a combination of both.

...The product thus obtained is a polar solvent such as methanol, butanol, calpitol, 2-butoxyethanol (ethylene glycol monobutyl ether9).
water-miscible organic solvents) and mixtures of these solvents with water.

It may be necessary to use mixtures of the above solvents to achieve complete solubilization.

For example, some of these alkyd resins exhibit relatively high solubility in high-boiling solvents such as butyl calpitol (diethylene glycol monobutyl ether) and 2-butoxycetanol; The amount of water available as part of the solvent system can be increased by adding additional solvents.

It is these alkyd resins that have been modified to be soluble in polar solvents and are referred to as water-reducible alkyd resins useful in this invention.

In addition to simple alkyd resins, alkyd resins modified by reaction with chemicals such as isocyanates, acrylic acid, etc., which are widely used to modify alkyd resins, can be utilized in the practice of this invention.

These modified alkyd resins are the same as those used in combination with organic solvent-based alkyd resins and further modified with neutralizable acidic groups so as to be soluble in polar solvents.

Note that the present invention is not limited to the modified alkyd resins described above.

That is, it is soluble in polar solvents or mixtures thereof, or polar solvent/water mixtures, and becomes water-insoluble by evaporation of aeration water at room temperature and atmospheric pressure, or by curing due to volatilization of the water-solubilizing amine component. Any convertible water-reducible polymer system can be used in the practice of this invention.

For best results, any resin selected should contain at least 5% by weight of molecules with a molecular weight of about 1000 or less, and preferably 10% by weight of molecules with a molecular weight of about 1000 or less. There must be.

If these conditions are met, the penetration of the wood cell wall into the free space is facilitated.

Molecules that are too large to enter the free spaces of the cell walls form a layer on the wood surface that serves both as a protective and a decorative layer.

Although all of the water-dilutable polymer systems described above are useful in the practice of the present invention in a broad sense, it goes without saying that there are differences in performance between individual resins depending on the application.

For example, there are differences in the stability of resin/solvent systems, and resin precipitation times vary from system to system.

Experience has shown that for relatively dilute resin solutions containing less than about 20% resin by weight, it is important to select resins based on stability.

For such a solution, one type of resin with optimal properties may be selected from among several resins.

Example 2, described below, involves a resin/solvent system that has relatively long-term stability at low resin concentrations.

Similar to alkyd resins that can be diluted with oil or organic solvents,
Water-dilutable alkyd resins or modified alkyd resins react with oxygen in the air to form water-insoluble products by cross-linking.

The rate of cross-linking can be significantly increased by adding small amounts, typically 0.05 to 10% by weight, of catalysts such as driers.

Examples of desiccants that can be used include calcium, cova/L/
), tintate or chelate salts of manganese and zirconium.

An unexpected discovery was that when the above-mentioned water-dilutable alkyd resin solution was applied to wood, it permeated through the wood cell walls and was then aerated to become water-insoluble.

Therefore, by utilizing this, it is possible to stabilize the wood cell walls and significantly improve the dimensional stability, that is, to reduce the tendency to expand and contract due to changes in humidity.

The same unexpected finding is that another wood treatment chemical that is normally water-soluble or soluble in the alkyd resin solution penetrates the wood cell wall when used in conjunction with the alkyd or modified alkyd resin solution.

Then, when the alkyd or modified alkyd resin is aerated and cured, it is fixed in the wood and hardly leaches out even when exposed to water.

This discovery can be used to treat wood with a number of chemicals that not only give it dimensional stability, but also give it various properties, including a long service life.

That is, by using a normally water-soluble fire retardant, it is possible to provide wood with permanent fire retardant properties that do not leach out even when water is applied to the wood.

Similarly, water-soluble wood preservatives, whether organic or inorganic, can be introduced into the wood to cure alkyds or modified alkyd resins, rendering them non-leachable, so that the wood retains these introduced compounds even under moisture or humid conditions of use. can do.

The invention can be applied in a variety of ways.

For example, if you want to give wood rolling resistance and dimensional stability,
It is sufficient to treat with a water-reducible alkyd resin containing a suitable desiccant, followed by air drying.

The amount of substance deposited on the wood cell walls is proportional to the concentration of said substance in the treatment solution.

This is true for binder polymers as well as ingredients such as wood preservatives and fire retardants.

The binder polymer used can be as high as about 70% by weight or as low as about 5% by weight.

Generally, a mixture of about 5% to about 30% by weight is preferred.

This is because if the concentration is higher than this, the viscosity of the solution becomes extremely high.

If the viscosity of the solution is too high, it will take a long time to impregnate the wood.

The viscosity can be reduced to some extent by heating the solution.

However, from a purely practical point of view it is preferred to utilize room temperature and relatively low concentration ranges.

Although a resin binder concentration of about 5% by weight does improve the dimensional stability of the treated wood and the fixing effect of other additives, it is necessary to almost completely prevent the leaching of the additives by water. The resin concentration should be at least about 8% by weight.

The amount of wood preservative or mixture thereof used also depends on the degree of protection desired.

For example, pentachlorophenol may be used at a concentration of about 0.5 to 6%, preferably about 2 to 5% by weight.

Oxidized tributyltin adducts are normally used at a concentration of about 0.1 to 0.5% by weight.

Similarly, fire retardants or mixtures thereof may be used at concentrations of about 2 to 15% by weight, depending on the degree of protection required.

Other wood treatment chemicals considered are copper 8-quinolinate and steel ammonium borate.

The wood can be treated sequentially or simultaneously with preservatives, fire retardants and resin binders.

If the wood is first treated with a fire retardant or wood preservative and then treated with the resin binder of the present invention, a higher level of protection is obtained than can be obtained with simultaneous treatments.

For example, if a fire retardant such as borax is used in the simultaneous treatment, the limit is 4% by weight, and even so, a large amount of borax must be deposited into the wood to achieve the desired level of fire protection. It is necessary to do so.

Under these circumstances, 10 to 1
A high concentration of boron can be fixed in the cell wall by first treating with 5% by weight of borax and then with the binder of the present invention.

Resin binders and other wood treatment chemicals may be contacted with the wood in any suitable manner.

Conventional methods such as brushing, spraying, dipping, or placing the wood under vacuum and applying a pressurized treatment solution at room or elevated temperature may also be used depending on the type of wood and the degree of penetration desired. Can be hired.

Conventional pigments, dyes, thickening agents, matting agents, and fillers, whether organic or inorganic, can also be added to the processing solution as desired.

Examples 1 The property enhancement of wood according to the present invention is reflected in resistance to dimensional changes due to moisture changes and dimensional changes of the wood itself.

For approximately 15 d maple samples impregnated with resin solutions of 20.40 and 60% strength (by weight) and air-dried for two weeks, the following dimensions at saturated moisture level and dry condition: The rate of change was observed.

The above results were obtained by soaking wood samples overnight in a resin solution having the composition shown in the table below.

Open drying was carried out at 150°C until constant weight (usually after about 3 hours).

It is clear from this experiment that the dimensional stability is significantly enhanced by impregnating the wood with the above solution, and that the dimensional stability imparted in the tangential direction is greater.

It is also clear that this treatment results in significant tangential and radial dimensional changes.

The increased dimensional stability also indicates that the polymer actually penetrates the cell wall.

Similar results were obtained when Shinanoki, Goyomatsu and Yurinoki were treated with the above solution.

It has also been found that wood treated with a resin solution and then air-dried for a week does not recover to its original dimensions.

The dimensional change rate obtained by processing the maple sample is as follows.

This also proves that the polymer does indeed penetrate the wood cell wall.

Examples ■ The wood treatment of the invention not only provides dimensional stability, but also significantly increases rolling resistance.

This was demonstrated by three equivalent proof samples.

Sample A1 was only subjected to kiln drying treatment, but there was relatively little conversion.

Sample A2 was kiln dried, hydrated by immersion in water for about 20 minutes, and then open dried.

Many transpositions were observed. Sample 3 was kiln dried and then immersed in the polymer system shown in the table below.

Very few small rolls were observed after open drying.

Examples ■ As already mentioned, wood preservatives and fire retardants that normally leach out of the wood when exposed to water, such as rain, can be largely fixed in the wood and rendered non-leaching by the present invention. .

Pentachlorophenol is widely used as a wood preservative.

When used as a preservative, pentachlorophenol is commonly dissolved in solutions of aromatic and aliphatic hydrocarbons.

When wood blocks treated with pentachlorophenol are leached with water, they rapidly lose the preservative.

That is, a wood block of 1- was treated with 5% by weight of pentachlorophenol and the chlorine content was analyzed using energy dispersive X-ray analysis (EDXA) before and after leaching with water (for 1 month). did.

Analysis results showed the absence of chlorine in the leached sample, confirming that most of the pentachlorophenol was leached out.

Another 14 wood blocks were treated with 5% by weight pentachlorophenol solution and 14% by weight water-diluted alkyd resin;
It was air-dried for 0 days.

This block also received E before and after (1 month) water leaching.
Chlorine content was analyzed using DXA.

Analysis revealed that the chlorine loss was extremely low and that the polymer had fixed the pentachlorophenol within the wood.

Other chemicals, such as fire retardants, can be added to the wood in the same way, making them non-leachable.

Processing solutions were prepared from the combination of Mixtures A and B shown in the table below.

Example (1) This example shows that, like the preservative in Example (2), a fire retardant can be deposited within the cell walls of wood and prevented from leaching by the resin.

The procedure of Example (2) was followed exactly, except for the step of adding 42P (5%) sodium borate to the binder mixture of Example (2).

Wood block used: 5cIrL x 10crrL x 1
/2crrL.

After treatment, the blocks were air dried at room temperature for two weeks.

Next, it was cut at the center of the width, divided into two parts, and one half was washed repeatedly with water and air-dried.

The washed and unwashed half-hogs were held at a distance of 10 crfL from the grain edge of the block and exposed to a lit torch.

Burning started after 8 minutes for both half-days.

For comparison, an untreated block was placed under the same conditions and began to scorch after 4 minutes.

The above description and experiments pertain to the practice of the invention using water-dilutable alkyd resins.

As already pointed out, the present invention can be carried out with any water-dilutable polymer system that is soluble in a polar solvent or a mixture of polar solvent and water, although it can later be converted into a water-insoluble stage. be.

In this regard, water-reducible film-forming resins comprising vinyl monomers have been found to have advantageous properties for the present invention.

This vinyl monomer-based water-reducible resin is converted to a water-insoluble form by evaporation of water and film formation and/or by volatilization of ammonia or amine reacted with acidic groups in the resin.

Water-reducible resins based on vinyl monomers have the advantage that they can be prepared with much less organic polar solvent than water-reducible alkyd resins.

In fact, some of these vinyl resins do not require any organic solvent at all and are prepared using only water as a solvent.

A small amount of a water-miscible organic solvent is used here to provide a vinyl resin that forms a film at room temperature and atmospheric pressure.

It is environmentally and economically advantageous to use a very small amount of organic solvent (generally less than about 10% by weight of the total composition, preferably less than 5% by weight).

The operational advantages are also quite significant.

The organic cosolvents used to impart water dilutability to the alkyd polymer mixture also act as excellent solvents for some of the dark chemicals present in natural wood.

Therefore, when such a solution is applied to wood, the dark-colored compounds are exposed to the surface, making the wood dark and detracting from its natural aesthetic appearance.

Furthermore, water-miscible organic solvents can cause problems in conjunction with water-soluble chemicals, such as preservatives and fire retardants, which are added to wood treatments to permanently deposit them in the wood.

That is, when such chemicals are added to a processing solution containing a large amount of organic solvent, the mixture separates into two layers: a resin co-solvent layer and a preservative and/or fire retardant layer.

In view of this phenomenon, it is almost universally impossible to use water-soluble chemicals for the preparation of a single wood treatment solution, and solutions containing large amounts of organic solvents can be used. This is limited to cases where it is used in combination with chemicals that easily dissolve in the mixture, such as fire retardants.

Such compounds are more expensive than water-soluble compounds and are often not as effective even in the same amount.

The use of vinyl monomer-based resins that require relatively small amounts of organic co-solvents avoids the problems described above that exist with processing agents that require large amounts of organic co-solvents.

Polymers, copolymers and homopolymers formed from vinyl monomers, such as acrylic polymers, are typically produced by reactions that result in relatively narrow molecular weight molecules.

As with alkyd resins, if a vinyl-based resin is selected, it should contain at least 5% by weight of resin molecules with a molecular weight of about 1000 or less, preferably at least about 10% by weight of resin molecules with a molecular weight of about 1000 or less. % of resin molecules.

In preferred embodiments, it is desirable to include molecules in the treatment solution that are large enough to not penetrate the cell walls of the wood and thus form an external coating that is both protective and decorative.

Therefore, as a preferred preparation method, two different types of vinyl
It is common to combine polymers, ie, vinyl polymers with small molecules that penetrate into the wood, and vinyl polymers with relatively large molecules that form a film on the surface of the wood.

The larger molecules generally have a molecular weight of about 20,000 to 2
00,000, with a typical composition having a molecular weight of 90,000
~110,000 molecules account for 95%.

Many of the emulsions obtained by emulsion polymerization of vinyl containing monomers can be used to prepare processing solvents.

An example of a monomer containing a vinyl group is vinyl.
Mention may be made of acetate, methyl methacrylate, ethyl ethacrylate, acrylamide, acrylonitrile, styrene, isoprene, malic anhydride, and the like.

Although monomers of the same type can be polymerized to form a homopolymer, it is preferable to control properties such as the minimum temperature for film formation and the hardness of the film after drying by appropriately selecting the blend of monomers. .

Polymerizations are often carried out in the absence of oxygen, using free radical releasing agents such as peroxides, and are usually carried out in the absence of oxygen.
In this case, the monomer or monomer mixture is suspended in water, stirred and the temperature controlled at a sensitivity higher than that required to separate the free radical releasing agent.

Many commercially available acrylic emulsions contain organic cosolvents that act as thickening agents and/or coalescing agents.

Other emulsions that form films at or below room temperature and are stable in the presence of additives are also available.

Low molecular weight polymers in the form of emulsions or clear solutions are synthesized in a manner very similar to the gravimetric reactions described above, but differ from polymerization reactions in that a suitable chain transfer component is included in the reaction mixture.

Emulsion polymers are of varying molecular weight (e.g., when prepared by utilizing acids such as acrylic acid, methacrylic acid or mixtures of these acids as part of the monomer mixture, amines or ammonia). When added to raise the pH towards the alkaline side, generally above 8 or 8.5, it tends to form a clear solution.

It is soluble in this form, but when utilized as a binder or film-forming agent, it loses ammonia or (if volatile amines are used for pH adjustment) volatile amines through evaporation and becomes water-insoluble. becomes.

When a mixture of high and low molecular weight polymers is used, the low molecular weight polymers, together with water and additives, penetrate the wood cell walls and are deposited within the cell walls as the water evaporates.

The high molecular weight polymer forms a film on the exterior surface that protects the wood from the elements and adds aesthetic appeal.

The inclusion of this surface film-forming component also allows for the addition of pigments and dyes to the treatment solution, providing the wood treatment and wood coating or staining system as a single mixture.

The weight ratio of high molecular weight resin to low molecular weight resin is generally 9.
5:5 to 50:50, preferably about 90:10 to 70:30.

When such dyed processing solutions are used, the dye doubles as an ultraviolet (UV) radiation absorber.

It is known that UV radiation degrades wood, so the addition of pigments further increases the useful life of wood.

The same objective can be achieved in the case of transparent coatings by adding UV absorbers.

Representative examples of UV absorbers are shown in the Examples above.

The following examples relate to typical processing solutions that can be prepared using resins formed from vinyl monomers and relatively small amounts of organic polar co-solvents.

In Example V, both the high molecular weight resin and the low molecular weight resin contain multiple acidic groups that are neutralized with ammonium hydroxide.

A highly soluble, aqueous, white, clear solution is thus obtained.

Example 3 relates to a treatment solution in which inorganic fire retardants and preservatives can be incorporated without phase separation because the concentration of organic polar cosolvent is relatively low.

Example V The total solid content of the resin in the above composition was 20%, and the ratio of 13-505 to Acrysol 527 in terms of solid content was 9.0:1.0.

Examples ■ Examples ■ Examples ■ Examples ■ The treatment solution of Example ■ was used to treat two 4" x 8" yellow cedar blocks.

That is, the blocks were immersed in the treatment solution for 15 minutes and then air dried overnight at room temperature.

One block was washed with tap water for 6 hours and dried again at room temperature overnight.

The two blocks were then exposed to the flame of a blowtorch held at a distance of 6" from the surface.

No flame remained on either block after the blowtorch was removed, but local charring appeared after 3 minutes of flame application.

A control block that is not treated at all becomes 1 when exposed to flame.
It ignited within minutes and continued to burn after the torch was removed.

As is clear from this experiment, the fire retardant was effective in suppressing the spread of flames, and even though it was originally a water-soluble compound, it could no longer be leached out.

EXAMPLE

A block of exactly the same size was used as a control block.

The treated and control blocks were soaked in water for 2 hours and dried in an oven under 250°C.

Inspection of these dried blocks revealed that the untreated blocks had translocations along the linearly arranged cells, whereas the treated blocks had no translocations at all.

This experiment proved that Example 2 can effectively stabilize wood.

The same experiment as above was repeated except that Acrysol 527 was omitted from the treatment solution of Example (1).

In this experiment, rollover occurred in both the control and treated blocks during the open drying process.

Thus, it has been established that high molecular weight acrylic polymers alone cannot stabilize wood.

Claims (1)

[Scope of Claims] 1. A method for treating wood for enhancing the properties of wood, which comprises adding a water-miscible solvent to a water-miscible solvent of a size that can enter the free spaces within the cell walls of the wood in the presence of the solvent. A solution (resin/solvent system) containing the molecule and a sufficient amount of water-dilutable resin to deposit an effective amount within the cell walls of the wood.
1. A method for treating wood for strengthening the properties of wood, which comprises contacting the wood to be treated with the wood and converting the resin within the cell walls into a water-insoluble form at room temperature and atmospheric pressure. 2. The method according to claim 1, wherein the solvent contains water. 3. The method of claim 2, wherein the solvent comprises an organic solvent miscible with water. 4. The method of claim 3, wherein the resin is an alkyd resin that hardens and becomes water-insoluble when exposed to air. 5. The method of claim 3, wherein the resin is formed from vinyl monomer. 6. The method of claim 5, wherein the resin is formed from an acrylic monomer. I. A method according to claim 5, characterized in that the resin comprises a film-forming emulsion which becomes water-insoluble upon evaporation of the solvent. 8. The resin contains an acidic atomic group that can be neutralized with an amine or ammonia to impart water solubility to the resin, and the resin becomes water-insoluble as the amine or ammonia volatilizes. A method according to claim 5. 9 At least 5% of the molecules by weight of the resin are about 10
The method according to claim 2, characterized in that the molecular weight is 0.00 or less. 10. The method of claim 9, wherein at least about 10% by weight of the molecules of the resin have a molecular weight of about 1000 or less. 11. Claim 10, characterized in that the majority of the molecules of the resin have a molecular size larger than that which allows them to enter the free space within the cell wall, forming a surface film on the wood. Method described. 12 The large molecular size of the molecules is approximately 20,000 ~
12. Process according to claim 11, characterized in that it has a molecular weight of 200,000. 13. The method of claim 9, wherein the resin is present in the solvent (resin/solvent system) in an amount of about 5 to 70% by weight. 14. The method of claim 10, wherein the resin is present in the solvent (resin/solvent system) in an amount of about 5 to 30% by weight. 15. The method of claim 14, wherein the resin is present in the solvent (resin/solvent system) at about 8% by weight. 16 A wood treatment chemical (a different wood treatment chemical than the water-dilutable resin) dissolved in a water-miscible solvent and in the presence of the water-miscible solvent within the cell walls of the wood. By contacting the wood with a solution containing a sufficient amount of a water-dilutable resin containing molecules of a size that allows them to enter the free space of the wood and depositing an effective amount within the cell walls of the wood, depositing an effective amount of the wood treatment chemical into the cell walls of the wood before converting the resin therein to a water-insoluble form, and then converting the resin to a water-insoluble form at room temperature and atmospheric pressure. A method for treating wood for strengthening the properties of wood, characterized by fixing the wood treatment chemical within the cell wall. 17. The method of claim 16, wherein the solvent comprises water and a water-miscible organic solvent. 18. Claims characterized in that the wood treatment chemical is present in a common solvent with the resin and is brought into contact with the wood at the same time as the resin so that both the wood treatment chemical and the resin are deposited within the cell walls. The method according to paragraph 16. 19. Claims characterized in that the wood treatment chemical is present in a common solvent with the resin and is brought into contact with the wood at the same time as the resin so that both the wood treatment chemical and the resin are deposited within the cell walls. The method according to paragraph 17. 17. A method according to claim 16, characterized in that the wood treatment chemicals are selected from wood preservatives and fire retardants. 21. A patent characterized in that the wood treatment chemical is selected from wood preservatives and fire retardants, and the water-miscible organic solvent does not exceed about 10% by weight of the solvent (resin/solvent system). The method according to claim 17. 22. The method of claim 21, wherein the water-miscible organic solvent does not exceed about 5% by weight in the solvent (resin/solvent system). 23. The method of claim 21 or 22, wherein the wood treatment chemical is water soluble. 24. A water-dilutable resin convertible to a water-insoluble form at room temperature and atmospheric pressure, a water-miscible solvent for said resin, and an effective amount of a wood treatment chemical dispersed in said resin and solvent. 1. A wood treatment composition comprising a solvent, wherein at least about 10% by weight of the molecules of the resin have a molecular weight of about 1000 or less. 25. The composition of claim 24, wherein the solvent comprises water and a water-miscible organic solvent. 26. The composition of claim 25, wherein said resin is a polymerized vinyl monomer. 27. The composition of claim 26, containing up to about 10% by weight of water and a water-miscible organic solvent. 28. The composition of claim 24, wherein the resin is present in the solvent (resin/solvent system) in an amount of about 5 to 70% by weight. 29 In the solvent (resin/solvent system), the resin is about 8
29. A composition according to claim 28, characterized in that it is present in a weight ratio of -30%. 30. A composition according to claim 24, characterized in that the wood treatment chemicals are selected from wood preservatives and fire retardants. 31. The method of claim 26, wherein the wood treatment chemical is a water-soluble salt and the composition contains up to about 5% by weight of a water-miscible organic solvent. Composition of. 32 characterized in that the majority of the molecules of said composition have a molecular size larger than that which allows them to enter the free space within the cell walls of wood, forming a surface film on the wood treated with said composition. A composition according to claim 2T. The weight ratio of high molecular weight resin to low molecular weight resin is approximately 95:
33. A composition according to claim 32, characterized in that the ratio is between 5 and 50:50. The weight ratio of high molecular weight resin to low molecular weight resin is approximately 90:
34. A composition according to claim 33, characterized in that the ratio is 10 to 70:30. 35. The composition of claim 34, wherein the high molecular weight resin and the low molecular weight resin are both acrylic copolymers. 36. A composition according to claim 32, characterized in that the resin is present in the form of an emulsion. 37. The composition of claim 32, wherein the resin contains sufficient acidic atomic groups to be soluble in an alkaline solution.