JPH0732312A - Manufacture of modified wood - Google Patents

Abstract

PURPOSE:To provide a method for a modified wood which prevents the oozing of a fireproof chemical and is of superior fine retardant properties and dimension stability. CONSTITUTION:A mixture of phenol resin and a fireproof chemical composed of a phosphorus and nitrogen compound having methylol and/or amino (for example, N-methyloldialkylphosphonopropionamide, a reaction product of guanidine phosphate and formaldehyde, guanylurea phosphate, ammonium carbamyl polyphosphate or the like) is contained in a wood, and then heat cured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a modified wood which is excellent in flame retardancy and dimensional stability by preventing exudation of a fireproofing agent.

[0002]

2. Description of the Related Art Conventionally, ammonium phosphate has been added to wood.
A method of imparting flame retardancy to wood by injecting a fire-preventive agent such as ammonium sulfamate, ammonium sulfate, borax, and boric acid is used. However, these fire-preventive agents have low water resistance, and when they are used, they elute when they are immersed in water, so that they have a drawback that the flame-retardant effect is also reduced. Further, the dimensional stability was not improved so much. On the other hand, as a method of imparting dimensional stability to wood, a method of impregnating wood with a phenol resin has been performed. Wood impregnated and cured with phenol resin showed excellent water resistance and dimensional stability, but no flame retardant effect was observed with phenol resin alone.

[0003]

DISCLOSURE OF THE INVENTION The present invention improves the above-mentioned drawbacks, and in particular, prevents the exudation of a fire-preventive agent, and is excellent in the efficiency of modified wood having excellent flame retardancy and dimensional stability.
An object is to provide an advantageous manufacturing method.

[0004]

According to the present invention, wood is allowed to contain a mixture of a phenolic resin and a fireproofing agent comprising a phosphorus / nitrogen compound having a methylol group and / or an amino group, and Provided is a method for producing modified wood, which is characterized by heat-curing, and in particular, the fire-preventive agent is N-methyloldialkylphosphonopropionamide (carbon number of alkyl group: 1 to 3), guanidine phosphate and formaldehyde. , A reaction product of guanylurea phosphate and formaldehyde, guanidine phosphate, guanylurea phosphate, ammonium carbamyl polyphosphate, or one or more kinds selected from the above, the method for producing modified wood. Will be provided.

That is, a phenolic resin contained in wood reacts with a fireproofing agent having a methylol group and / or an amino group to form a cured product having a crosslinked structure, and the fireproofing agent is firmly fixed in the wood. Therefore, even if the modified wood is used by dipping it in water, the fireproofing agent is less likely to elute, the water resistance is good, and it is found that a modified wood having excellent flame retardancy and dimensional stability can be obtained. Has been completed.

The present invention will be described in more detail below. The wood used in the present invention may have any shape such as a plate, a column or a block that can be used as the wood itself, and there is no particular limitation on the tree species. Wood having a high water content can also be used, and pretreatment such as drying may be performed in advance.

As the phenolic resin, phenol / formaldehyde initial condensation resin, phenol / melamine / formaldehyde co-condensation resin, phenol / melamine / urea / formaldehyde co-condensation resin, mixture of phenol resin and melamine resin, phenol resin and urea Examples thereof include a mixture of resins. Further, the phenolic resin is soluble in water, alcohols, ketones and the like alone or in a mixed solvent, and when incorporated in wood, it easily enters the cell wall of wood and has an average molecular weight of 10
A value of 00 or less, preferably 600 or less, is suitably used.
If the average molecular weight exceeds 1,000, the cell wall of wood cannot be made uniform and cannot be sufficiently inserted, and the dimensional stability effect becomes insufficient, which is not preferable.

As the fire-preventive agent, a phosphorus-nitrogen compound having phosphorus and nitrogen atoms in the molecule and having a functional group capable of reacting with a phenol resin such as a methylol group or an amino group is used. These phosphorus / nitrogen compounds are excellent in compatibility with phenolic resins, and for example, N-methyloldialkylphosphonopropionamide (alkyl group carbon number: 1 to 3) is a reaction product of guanidine phosphate and formaldehyde. Reaction product of acid guanylurea and formaldehyde Guanidine phosphate Guanyluyl phosphate Ammonium carbamyl polyphosphate.

The mixture of phenolic resin and fire-preventive agent is
Usually, it is prepared by dissolving the phenolic resin in a solvent capable of dissolving it. At this time, it is preferable to prepare by dissolving so that the concentration becomes 5% by weight or more. If the concentration is less than 5% by weight, the effect of improving flame retardancy and dimensional stability becomes insufficient, which is not preferable. The weight ratio of the phenolic resin and the fire-preventive agent is preferably 1: 5 to 5: 1, more preferably 1: 5.
2 to 2: 1 is preferred. When the amount of the phenolic resin is large, the flame retardant effect is lowered, and when the amount of the fireproofing agent is large, the amount of elution when immersed in water is large, which is not preferable.

An example of the manufacturing method of the present invention will be specifically described below by following the procedure. First, wood is dipped and impregnated in a mixed solution of the phenolic resin and the fireproofing agent. The degree of impregnation can be appropriately selected depending on the purpose whether it is only the surface layer portion or the entire surface to the inside.
In particular, it is preferable to carry out such impregnation under reduced pressure, under pressure, or under reduced pressure and pressure because the impregnation of the mixed solution into wood can be further promoted.

Next, the impregnated wood is taken out of the mixed solution and heated to 100 to 180 ° C. At this time, the phenolic resin in the impregnated wood is cured, and at the same time, it reacts with the fireproofing agent to firmly fix the fireproofing agent in the wood. The reaction time is generally 5 minutes to 6 hours,
It is preferably 10 minutes to 3 hours.

The curing reaction of the phenolic resin of the present invention can be carried out without a catalyst, but for the purpose of further shortening the curing time, a general catalyst used for the curing reaction of the phenolic resin can be used together. Examples of the catalyst include inorganic acids such as hydrochloric acid and sulfuric acid, and organic acids such as benzenesulfonic acid and toluenesulfonic acid.

As the heating method, a conventionally known heating method such as external heating or internal heating such as high frequency heating or microwave heating can be applied. In particular, before heating, by removing the solvent by drying at a temperature lower than the temperature at which the phenolic resin in the impregnated wood reacts with the fireproofing agent, a concentration gradient occurs, and the phenolic resin and the fireproofing agent are separated. A large amount is filled in the cell wall, and more excellent dimensional stability is obtained. The drying temperature at this time varies depending on the type and blending ratio of the phenolic resin and the fireproofing agent, but is usually preferably 60 ° C. or lower. Further, as the drying method, a conventionally known heating method can be applied as in the above. Furthermore, if such drying is performed under reduced pressure, it can be dried more efficiently.

In addition, as a method of incorporating the mixed solution in wood, a coating method or the like can be used.

In the process for producing the modified wood of the present invention, other additives such as colorants, penetrants, surfactants, insect repellents, fungicides, preservatives, weather resistance improvers and defoamers. Other flame retardants may be used. The modified wood thus obtained is a product as it is and does not need to be washed and dried again.

[0016]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but it goes without saying that the present invention is not limited to the examples.

Example 1 In a 300 ml tall beaker, tangential direction 30 mm × radial direction 30 mm × fiber direction 5 m for measuring dimensional stability.
m and oxygen index for measuring tangential direction 3.5 mm × radial direction 6 mm × fiber direction 120 mm, cypress dried wood was put, and after suctioning for 30 minutes under reduced pressure (25 mmHg) in a desiccator, the fire-preventive agent N-methylol 100 parts by weight of a phenol resin (average molecular weight 166, solid content 66%) was added to 100 parts by weight of dimethylphosphonopropionamide, and an aqueous solution having a nonvolatile content of 15% by weight was injected from above to impregnate it. . Next, this impregnated wood was heated in a hot air dryer at 40 ° C. to remove water, and then heat-cured at 140 ° C. for 3 hours to obtain modified wood.

Example 2 In a 300 ml tall beaker, tangential direction 30 mm × radial direction 30 mm × fiber direction 5 m for measuring dimensional stability.
m and oxygen index for measuring tangential direction 3.5 mm × radial direction 6 mm × fiber direction 120 mm, cypress dried wood was put, and after suctioning for 30 minutes under reduced pressure (25 mmHg) in a desiccator, the fire-preventive agent N-methylol Solid content was obtained by mixing phenol resin (average molecular weight 166, solid content 66%) and melamine resin (molecular weight 190, solid content 60%) in a weight ratio of 4: 1 with respect to 100 parts by weight of dimethylphosphonopropionamide. An aqueous solution containing 50 parts by weight of non-volatile components added in an amount of 100 parts by weight was injected from above to impregnate. Next, this impregnated wood was heated in a hot air dryer at 40 ° C. to remove water, and then heat-cured at 140 ° C. for 3 hours to obtain modified wood.

Example 3 A modified wood was obtained in the same manner as in Example 1 except that a compound obtained by reacting 1 mol of acidic guanidine phosphate and 2 mol of formaldehyde was used as a fireproofing agent.

Example 4 Using the high-concentration liquid of Example 3 (nonvolatile content 50% by weight), the impregnation amount was increased to obtain modified wood by the same operation as in Example 1.

Example 5 As a fire protection agent, a reaction product of 1 mol of guanidine phosphate and 2 mol of formaldehyde was used to prepare a mixed solution with the phenol / melamine resin of Example 2, and the modification was carried out in the same manner as in Example 1. I got wood.

Example 6 Water-soluble ammonium carbamyl polyphosphate represented by the following structural formula (Formula 1) as a fire retardant

[Chemical 1] With respect to 100 parts by weight, 10 parts by weight of a nonionic surfactant and a phenol resin (molecular weight 166, solid content 66
%) And methanol at a weight ratio of 2: 1 and 100 parts by weight in terms of solid content is added to the mixture to give 15% by weight of non-volatile content.
Modified wood was obtained by the same operation as in Example 1 using the solution described above.

Example 7 As a fire-preventive agent, an aqueous solution was prepared by mixing a reaction product of 1 mol of guanylurea phosphate and 1 mol of formaldehyde with a phenol / melamine / urea / formaldehyde cocondensation resin to give a nonvolatile content of 50% by weight. A modified wood was obtained in the same manner as in Example 1.

Comparative Example 1 The same operation as in Example 1 was carried out using an aqueous solution containing only a phenol resin having a nonvolatile content of 15% by weight, without using a fireproofing agent.

Comparative Example 2 The same operation as in Example 1 was carried out using an aqueous solution of N-methyloldimethylphosphonopropionamide, which is a non-volatile component having a nonvolatile content of 15% by weight, without using a phenol resin.

Comparative Example 3 The same operation as in Example 1 was carried out using an aqueous solution containing only the guanidine phosphate as a fire-preventive agent having a nonvolatile content of 15% by weight and a formaldehyde reaction product, without using a phenol resin.

Comparative Example 4 The same operation as in Example 1 was carried out except that ammonium phosphate was used as the fire-preventive agent.

Comparative Example 5 An untreated cypress was used as a comparative example.

Physical Property Test of Modified Wood The modified wood obtained from Examples 1 to 7, the treated wood of Comparative Examples 1 to 4 and the untreated wood of Comparative Example 5 were subjected to a physical property test. (Weight increase rate) Obtained by the following equation (1) (Equation 1), and the results are shown in Table 1.

[Equation 1]

(Test of Dimensional Stability and Elution Amount) A dry water repeating test was conducted as follows. That is, the test piece is 105 ° C
After drying with a hot air dryer, measuring its size and weight, immersing in distilled water and depressurizing for 30 minutes (25 mmHg)
And left for 24 hours. Then, these were taken out and the dimensions of the water-absorbing test piece were measured to determine the anti-swelling ratio (the higher this value, the better the dimensional stability). Next, these water-absorbed test pieces were dried at 40 ° C. for 4 hours and then at 105 ° C. for 20 hours, and then the weight of the test piece was measured to determine the elution amount. The results are shown in Table 1. The anti-swelling rate is defined by the following equation (2) (equation 2), and the elution amount is defined by the following equation (3) (equation 3).

[Equation 2] (In the formula (2), V₁Represents the swelling ratio of untreated wood, V₂
Represents the swelling ratio of treated wood. )

[Equation 3] (W in formula (3)₁Of treated wood before dry water repeat test
Represents dry weight, W₂Is treated wood after repeated dry water tests
Represents the dry weight of the material. )

(Flame Retardancy Test) The flame retardancy was examined by the oxygen index method. For the oxygen index method, a combustion test was performed based on JIS K7201. The results are shown in Table 1.

[0032]

[Table 1]

[0033]

EFFECTS OF THE INVENTION According to the present invention, a thermosetting resin such as a phenolic resin and a fireproofing agent are simultaneously impregnated and cured in fine voids in the cell walls of wood. It is possible to obtain a modified wood having excellent flame retardancy and dimensional stability. Further, since the phenol resin impregnated in the wood is cured and the fireproofing agent is fixed, it is less likely to elute even if it is used by condensation or immersion in water. Furthermore, as a secondary effect, it is possible to prevent or suppress the decay and damage of ants caused by various decay fungi and termites. Thus, the modified wood having excellent properties obtained by the production method of the present invention is suitable in many fields such as building materials, furniture materials, and, for example, columns, beams, foundations,
It is used for base materials, floors, eaves, shutters, outer wall materials, desks, bookshelves, etc.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Noriyuki Shiina 1-33 Yamadahigashi, Suita City, Osaka Prefecture C-1011 (72) Inventor Yuji Kameoka 5-4-10-105, Kemamachi, Miyakojima-ku, Osaka City, Osaka Prefecture (72) ) Inventor Haruhiko Kuda 4-10-14 Minami Yamamotocho, Yao City, Osaka Prefecture

Claims (2)

[Claims] 1. A modification characterized in that wood is mixed with a mixture of a phenolic resin and a fire-protective agent consisting of a phosphorus / nitrogen compound having a methylol group and / or an amino group and then cured by heating. Wood production method. 2. The N-methyloldialkylphosphonopropionamide (the carbon number of the alkyl group:
1-3), a reaction product of guanidine phosphate and formaldehyde, a reaction product of guanylurea phosphate and formaldehyde,
The method for producing modified wood according to claim 1, which is one or more selected from guanidine phosphate, guanylurea phosphate and ammonium carbamyl polyphosphate.