FI90745B - Fire-protection agent in the form of an aqueous solution for wood material - Google Patents

Description

90745

This invention relates to a room temperature curable, expandable swellable layer-forming (on heating) and weatherproof flame retardant for use on the surfaces of wood materials, and to fire resistant wood materials.

Wood materials have long and widely been used as furniture materials and for other purposes. In many countries around the world, fire regulations have been tightened in recent years with regard to the flammability of wood material, which is an essential disadvantage of wood. Nevertheless, so far only a few technologies have been developed to enable the efficient and economical weathering and fire prevention of wood materials, and this has significantly contributed to the decline in wood material consumption worldwide.

It is a primary object of the present invention to provide an effective solution to the problem described above.

The method of coating wood materials is one of two methods by which wood materials can be made fire resistant by coating, painting, spraying, dipping, etc. Compared to the second method of fire protection, i.e. vacuum treatment, coating differs from this as follows:

Coating- Vacuum pressure _method_method 30 Handling equipment costs very low very high Handling time and power short and good long and low 35 On-site handling easy impossible 2

Coating Vacuum pressure Method Method Very small, usually loss of strength of the treated wood material, except for a small amount of very thin wood substrates.

Fire resistance in the method available in the method after weathering available 10 a few many types of flame retardants, cheap substances flame retardants 15

In the vacuum pressure method, the internal structure of wood materials (e.g. pipes) is impregnated with a flame retardant solution by means of an expensive autoclave. The method is time consuming 20 and cannot normally be applied at the work site. The coating method, on the other hand, is very effective, but has not gained wider acceptance, perhaps because no highly weather-resistant flame retardant formulation has been available.

25 The vacuum method still plays a dominant role in making wood materials fireproof because it achieves excellent weather resistance. This is despite the fact that the processing step is complicated and its efficiency is low. Studies have been performed on the basis of a known method in which cellulose fibers (e.g. cotton fabric) are treated to be refractory with methylated products of dialkylphosphonopropionamides or their homologues (as described in e.g. GB 1,011,572). Studies have sought to provide a room temperature curable flame retardant.

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90745 3 neformulation for wood materials with particularly good water extraction resistance or weather resistance. However, the task has not been easy, as the comparative examples below show. There are three reasons for this: First, it is assumed that the mechanism or mode of absorption of the flame retardant differs depending on whether the target is natural wood or completely pure cellulose fibers with significantly different morphology and plant anatomy and considerable chemical composition. For example, U.S. Patent No. 2,927,050 describes these aspects as follows: "In fibrous substrates, substantially discrete fibers intertwine so that their interstices can be filled with an aqueous medium by capillary forces between all surfaces of the fibers. The individual fibers contain relatively little cellulose and the resulting materials are But in wood substrates, the cellulosic fibers bind together into a relatively impermeable solid-20 body with little capillary force.The surface area of the piece of wood is small compared to the amount of surface area it contains and its ignition temperature is relatively high.For these reasons, the fire retardant organic fibrous materials to be fire-resistant, is not likely to make wood fire-resistant because its fire-retardant ability is likely to be destroyed during the time taken to reach the ignition temperature of the wood, and / or or because it is difficult to cause the non-volatile substance to penetrate a solid piece of wood ".

30 The following is what is commonly known about impregnating wood substrates with flame retardants. U.S. Patent No. 3,398,019 discloses that impregnation must be performed so that the fire retardant is extended to such an extent that the wood fibers can be insulated from heat. The publication further discloses that, to the best of our knowledge, only the use of a chemical flame retardant that impregnates this thick wood substrate can produce a Building Material that provides adequate flame retardancy and is commercially acceptable.

Second, under curing conditions at 100 ° C or lower, the curing reaction of the phosphorus-containing flame retardant and the wood material and / or the condensation resin used together is completed and the flame retardant is mostly removed by water extraction.

10 Third, when wood material treated with any of the cellulosic fabric treatment formulations known in the literature is contacted with a flame to heat the cured layer of the coated surface, a sufficiently fire resistant, charred and foamed swollen layer is formed (e.g. not correct).

The present invention provides fire resistant wood substrates that will last outdoors for at least 5 years 20 even in Japan or Houston, Texas, where rainfall is high and the climate varies over four seasons, or even in Southern California, where temperatures are high and sunshine is strong during the dry season.

The present invention is supplemented by a limited set of certain flame retardant formulations which can withstand the harsh outdoor climate as mentioned below. These formulations are from the wide range of flame retardant formulations disclosed in U.S. Patent 4,585,703 (corresponding to JP Patent No. 89102/1984 or 122560/1984). 30 It was first decided to use the sprinkling method described in ASTM E108-80a (fire test of roof covering) for an awkward outdoor climate. For some reason, however, it was not used. In this method, only sprinkling and subsequent drying by heating at 60 ° C affect the cured fire retardant formulation on the 35 wood substrate.

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90745 5 floors. Instead of this method, a method believed to be closer to the actual external conditions was used, i.e. the accelerated weather test described on pages 10-12 of C. A. Holmes' article entitled "Evaluation 5 of fire-retarted treatments for wood shingles"; U.S.D.A. Forest Service Research Paper FPL 158-1971; published in U.S. Pat. Department of Agriculture, Forestry Service, Forest Service Laboratory, Madison, Wis., USA. This method was modified to make the weather conditions slightly more difficult, and these conditions were used as a measure to assess weather resistance.

In this accelerated weather test, a box - shaped stainless steel device with the following equipment and function was used (see

15 ASTM D2898 Method B): (1) For fire testing, there are two rows, each with 12 plates (width 30.48 cm and length 78.74 cm) that can be allowed to lean against the device in a tilt ratio of 5:12 (5 per 12).

20 (2) The test plates are ultraviolet irradiated with PS-type solar lamps, power 275 W (one area per 0.74 m2) in the wavelength range 280 to 400 nm and a maximum wavelength of 365.4 nm at a distance of 66.04 cm perpendicular to the surface of the test plates .

25 (3) At the top of the box there are two spray nozzles for spraying water from 1 to 16 ° C. Water can be recycled.

(4) The temperature inside the box can be maintained constant by hot air recirculation provided by a heater with a 30 1 800 W fan.

(5) The sprinkling test, ultraviolet irradiation at a specified temperature and the termination of the test can be performed automatically according to a predetermined time schedule.

The conditions for this 1000 hour accelerated weather test <35 were: 6 (a) The amount of sprinkling was 12,344 liters / m2 (corresponding to an amount of about 740.6 mm per hour).

(b) After ultraviolet irradiation, the temperature was raised to 65.56 ° C in 15 minutes.

5 (c) The locations of the cover plates used in the fire resistance test were varied in the device in the appropriate order twice a week to avoid differences due to location.

(d) The following tests were performed for 24 hours 10 and repeated continuously for 42 days: I) 4 hours of water spraying; II) 4-hour solar lamp irradiation at 65.56 ° C (150 ° F); III) 4 hours of water spraying; IV) 4-hour solar lamp irradiation at 65.65 ° C (150 ° F); V) 8 hours of rest.

(e) The test plates were finally conditioned indoors at 30% humidity and 26.67 ° C (80 ° F) until the weight of 20 had stabilized.

The author of the above publication evaluates the intensity of these accelerated test conditions as follows: (I) If the amount of water dripping onto the surface of the roofing sheet samples is compared to rain, the total amount of water is 254 nm 25 (10,000 inches) over a 1,000 hour period. During the period, the amount of water sprayed on each sample, which is 1,016 mm (40 inches) per year, corresponds to the total amount of rain that would drip on a sample of this size and flow over 35 years if the sample were placed on the eaves of an average 55-meter water roof.

(II) High temperature ultraviolet irradiation at 65.5 ° C and subsequent cold water spraying at 2-16 ° C served as a hot-cold bath. This forces the jet to penetrate deeper into the wood to further dissolve or dilute any water-sensitive flame retardants in the wood.

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90745 7 chemicals, which speeds up the extraction effect.

The method described above in U.S.D.A. The conditions of EPL-1971 are very harsh in terms of sprinkling, ultraviolet irradiation and hot-cold odor effect and correspond exactly to at least five years in real weather conditions in areas with a harsh climate as described above. In the practice of the present invention, these conditions have been used as a measure to evaluate weather resistance.

It has been found that when wood substrates treated according to the method of U.S. Patent No. 4,585,703 (e.g., wood substrates treated in Examples 1, 3, and 4 of Japanese Laid-Open Patent No. 89102/1984, and Japanese Laid-Open Patent Publication No. 15 122560 / 1984 room temperature curable flame retardants) are tested by the USDA of the above method According to the FPL-1971 accelerated weather test, the flame retardancy is markedly reduced due to the dissolution of the coating flame retardant, and the appearance is clearly deteriorated qualitatively, i.e., cracking or chalking occurs. Thorough research into these methods has been continued and it has been possible to create a flame retardant, in particular a flame retardant for wood materials, which can be cured at room temperature under very limited conditions and which can be used to obtain fire-retardant wood substrates that retain their fire resistance and appearance. after they have passed the method of the USDA Accelerated weather test in accordance with FPL-1971 for more than 1,000 hours. Thus, a new requirement has been added to the basic conditions of the inventions of the two above-mentioned JP patent applications.

The present invention relates to an aqueous flame retardant for wood materials which contains 100 parts by weight to 35 parts by weight of water-soluble 3- (dialkylphosphono) propionamide of the general formula R'- ° \, ° / PN '= 5 r2-o wherein Rx and R2 are each an alkyl group having 1 to 3 carbon atoms and R3 is a hydrogen atom or a methyl group, and at least 100 parts by weight of water-soluble melamine resin, characterized in that it has a pH not higher than 3.

The present invention also relates to a refractory wood material prepared by treating a wood material with an aqueous flame retardant containing 100 parts by weight of water-soluble 3- (dialkylphosphone) propionamide of the general formula R'-°. f 20 PR, / \ »R2-O-ch2chconh2 wherein each of Rx and R2 is an alkyl group having 1 to 3 carbon atoms and R3 is a hydrogen atom or a methyl group [in particular at least one compound from the group 3- (dimethylphosphono) propionamide (used DMPPA), 3- (diethylphosphono) propionamide, 3- (di-n-propylphosphono) propionamide and 3- (diisopropylphosphono) propionamide], and at least 100 parts by weight, preferably 30 to 400 parts by weight, based on solids. parts and more preferably 170 to 230 parts by weight of a water-soluble melamine resin [especially in the form of a precondensate or condensate which is highly condensed but still water-soluble in which the methylol group is fully or partially etherified with an alcohol having preferably 1 to 3 carbon atoms and the structure of which has amino groups

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90745 9 or imino groups have, on average, not more than three unreacted reactive hydrogen atoms (i.e. an etherified product consisting of hexamethylol melamine, pentamethylol melamine-1, tetramethylol melamine or trimethylol melamine-5 Preferably the pH is 2.5 to 1.5 adjusted with acidic ingredients, preferably hydrochloric acid.

The wood materials of the present invention can be treated to optionally control the condensation time (gel throat) of the flame retardant by adding water and water-soluble alcohol in a controlled ratio to the flame retardant of the invention, and applying the flame retardant to the wood materials in an amount of 150 g / m 2. m2 calculated as a planar surface, and is preferably cured at a temperature not exceeding 100 ° C.

In fulfilling these conditions of the present invention, a screening test was found to be very advantageous, in which several small molds (each side 20 cm long and 5 mm high) were first made by attaching rectangular glass sheets measuring 1 cm x 5 cm to four sides of a square flat glass sheet. The length of each side of the Ta-25 sol plate was 22 cm. Various flame retardant formulations with a solids content of about 60% in the form of an aqueous or water / methanol solution were poured into the molds to give 17 g in each mold and fully cured by standing for 7 days at room temperature (20 ° C). The cured products were removed from the molds as solid flame retardant films with a thickness of 0.21 to 0.23 mm. These films were then tested in a weather test similar to the above method in U.S.D.A. FPL-1971, with the difference that instead of spraying water-35 in the precipitation test, the membranes were immersed for 16 hours in water at 10 ° C and the same intensity of ultraviolet irradiation was performed for 8 hours at 65 ° C (the membranes were inverted at the beginning of each new cycle), and operations formed a single episode.

5 First, the residual weight of the film at the end of the weather test was calculated from the following expression:

Weight of dried film Remaining after the weather test 10 weight (%) = _ X 100 (A)

Weight of dried film before weather test

The amount of phosphorus remaining in the film at the end of the weather test 15 was calculated from the following expression:

Phosphorus content of the dried film Residual phosphorus after the weather test (%) amount (%) = _ X 100 20 Amount of phosphorus (B) of the dried film before the weather test (%)

Phosphorus was determined as follows:

About 0.2 to 0.3 g of sample was accurately weighed and added to a 50 ml Kjeldahl flask. 10 ml of water and 5 ml of 98% concentrated sulfuric acid were added and the sample was decomposed by heating until the solid had disappeared. To complete this digestion, 3 drops of 60% perchloric acid were added. This operation was repeated until the solution was completely clear. The solution in which the sample was completely disintegrated was taken into a 25 ml volumetric flask and this dilution was taken with a 1 ml volumetric pipette into a 50 ml volumetric flask. 15 ml of pure water and 5 ml of a 3.55% aqueous solution of ammonium molybdate, a 0.12% aqueous solution of ammonium metavanadate and a 12% aqueous solution of ammonium perchlorate were added. The total volume of solution 90745 11 was adjusted to 50 ml by adding water.

After standing for more than 30 minutes and the color stabilizing, the absorbance of the solution was measured with a spectrophotometer using monochromatic light having a wavelength of 5,400 nm. The phosphorus content was determined from a calibration curve drawn from the results obtained by measuring the color of the phosphoric acid solution of known concentration obtained as described above.

Using the values (A) and (B) obtained above, the phosphorus-10 concentration retention was calculated from the following expression: (A) x (B)

Phosphorus retention = _ (%) (C) 100 15

In addition, weather-induced weight changes in the cured melamine resin were monitored by determining the quantitative nitrogen by a Kjeldahl digestion method in a known manner. It was found that the test procedure 20 described above was quite suitable.

Simultaneously, different wood substrates were coated with various flame retardant formulations of the invention and beyond, cured by standing for 10 days at room temperature, and the coated substrates were tested in a weather test according to the method of the above-mentioned U.S.D.A. According to FPL-1971, the coating was then scraped accurately with wood over a defined area and the retention of phosphorus content and retention of the cured melamine resin was measured, and finally the weather resistance achieved in both test methods was compared. It was found that the 20-cycle (480 hours) weather test according to the simplified method using a film was almost identical to the 42-cycle (approximately 1,000 hours) weather test according to U.S.D.A. According to FPL-1971. Furthermore, since even a small difference in formulation could be accurately determined as the difference in quantitative performance, the simplified membrane method described above was very useful. The details of the test are apparent from the examples and comparative examples below.

The following is a typical formulation of the present invention (the formulation of Example 1).

By weight - 70% 10% methanol solution of 3- (dimethylphosphono) propionamide (obtained by reacting dimethyl hydrogen phosphite with acrylamide using a methanolic solution of sodium methylate as catalyst; abbreviated as DMPPA) 275 - 70% water-soluble methylated hexamethylene abbreviation MMM) 580 - MEGAFAC F833 (penetrant, fluorinated hydrocarbon type amphoteric surfactant; manufactured by Dainippon Ink and

Chemicals, Inc.) 10 20% to 20% hydrochloric acid (as HCl) 125 (as 25HCl) - Defoamer (e.g. NOCP0 NDW; manufactured by Diamond Shamrock Co.) 1 - Water 9_25 total 1,000

Huom.I

pH 2.0

Density at 20 ° C 1.17 30 Solids content 62.6%

Gel milling time (closed container) approx. 9 hours (20 ° C) (solvent; water / methanol * 97: 3)

Coating time of the coating layer approx. 5 hours (20 ° C)

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Instead of 275 parts of DMPPA, a similar compound was used separately and formulated as described in Comparative Examples 1 to 4, for example (A) 275 parts by weight of a 70% aqueous solution of N-methylol-3- (dimethylphosphono) -5-propionamide having formula CH, 0 0

V

ch3o ^ ^ CH2CH2CONHCH2OH

10 (used as DMPPA-CH2OH) and known as a flame retardant for cellulose fibers (compound from JP 13976/1966 or GB 1 011 572); (B) 275 parts by weight of a 70% methanol solution of 3- (dimethylphosphono) propioniamine-15-din of formula

CH.O 0 .CH, OH

3 \ II / 2, pch2ch2con / \

CH30 CH2OH

20 [used as DMPPA- (CH2OH) 2] and described in JP Patent Publication 30992/1971 as a flame retardant for cellulosic fibers; (C) 275 parts by weight of N-methylol-bis [S- (dimethylphospho-25-phono) propionamide] of the formula H-CO 0 O OCH,

PCH2CH2C0N '- CH2-NH-0CCH2CH2P

H 2 CO CH 2 OH 0 CH 3 O 3 (used as DMPPA-DMPPA-CH 2 OH) and described in JP Patent Publication No. 37797/1971; or (D) 275 parts by weight of bis [B- (dimethylphosphono) propionamide] (used as DMPPA-DMPPA) and which is the unmethylated product of (C) above.

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Each of these formulations was cured as described above for 7 days at 25 ° C in a mold. Each film formed was allowed to undergo one weather cycle according to the simplified membrane weather test described above. It was surprisingly found that the phosphorus retention of the formulation of Example 1 was about 70% using crude DMPPA containing 4-6% phosphite salts such as sodium monomethyl phosphite and / or sodium phosphite and / or unreacted dimethyl hydrogen phosphite. When DMPPA was purified to a purity of about 99% by removing the above impurities, e.g., by recrystallization or using ion exchange resins or an ion exchange membrane method, the phosphorus retention was greater than 90%. In the same tests using cured films containing the flame retardant compound (A), (B), (C) or (D), each concentration retention was less than about 50% and no phosphorus retention was more than 60%, that is, in short, the flame retardant had for the most part been extracted out by the time of the weather test -20 na.

The reason for such a low level of weather resistance when the application rate as a solid was 100 to 400 g / m 2 was probably the difficulty in condensing the flame retardant layer [consisting of any of the flame retardants (A), (B), (C) 25 and (D) described above and not not according to the invention] without curing to the extent that a completely water-insoluble solid is formed. In order to achieve unwashable flame retardancy with cellulose fibers when using these compounds (A), (B) and (C), it is necessary to use melamine resin in combination and heat treat the impregnated fabric for about 5 minutes at 160 ° C. Curing of fire retardant coatings on wood surfaces at room temperature is desirable because high temperatures degrade the quality of wood materials and such heat treatment is commercially difficult to perform. It has been shown that when cured at room temperature 90745, these flame retardants containing methylol groups are not suitable for achieving good weather resistance. The above-mentioned compound (D) does not contain a methylol group, but its curing ability when condensed with melamine-5 niharine at room temperature is much lower than that of the flame retardant of the present invention, and as shown in Comparative Example 4, the phosphorus retention was very low when the film was had to go through one period of a simplified weather test.

In order to achieve a high level of weather resistance with the formulation of Example 1, it is necessary that the methylated methylol melamine is a precondensate or condensation product with a sufficient degree of condensation to consist of water soluble and preferably consisting of . When a water-soluble melamine containing a small amount of reactive groups, e.g. methylated trimethylol melamine, is used, the weather resistance is slightly lower. Water-soluble amino resins other than said melamine resins, e.g. methylated products of alkyl compounds such as urea, thiourea, guanidine salts, guanidine ureas or dicyandiamide or alkylated methylated products or mixed condensates of these amino compounds and melamine can be used according to the invention, in admixture with melamine resin. As the proportion of such an amino resin in the mixture increases, the flame retardant film cured at room temperature becomes brittle or its weather resistance clearly decreases. The use of acetoguanamine or a mixed condensate of benzoguanamine-amine and melamine leads to a decrease in weather resistance, but the flame retardant film may plasticize slightly. But since the 3- (dialkylphosphono) propionamide used in this invention has an excellent plasticizing effect, there is no particular advantage in using such guanamines 16.

A particularly important feature of the present invention is that the flame retardant formulation is used after its pH has been adjusted to a very narrow range of not more than 3 and is preferably 2.5 to 1.5.

When various acid catalysts were added to the formulation of Example 1 instead of 20% hydrochloric acid, the pH values of the formulation are given in the following 10 tables 000 parts by weight).

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Acid catalyst Stir- pH immediate- Ratio relative to the mixture _ (%) _ after incorporation_ 20 p-toluenesulfonic acid 5 3.9 not ammonium chloride according to the invention 5.20 - "- nitric acid 5 2.98 nitric acid according to the invention 7 2 .45 - "- nitric acid 9 1.90 -" - nitric acid 10 1.60 - "- sulfuric acid 4 3.35 not sulfuric acid according to the invention 7 2.35 sulfuric acid according to the invention 9 1.90 -" - hydrochloric acid 3 2.50 - "- 35 hydrochloric acid 3,5 2.20 -" - hydrochloric acid 4 2.00 - "- hydrochloric acid 5 1.55 -" - hydrochloric acid 6 1.10 - "- phosphoric acid 5 3.27 not according to the invention 40

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90745 Of these, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid and nitric acid are useful catalysts in this invention. Hydrochloric acid is most preferred because the amount required can be kept small and excellent weather resistance is achieved.

The formulation (1,000 parts by weight) in Example 1 of the applicant's Laid Open Japanese Patent Publication No. 122560/1984 contains 250 parts by weight of 70% of 3- (dimethylphosphono) propionamide, 500 parts by weight of 70% of methylated 10 methylol melamine. , 10 parts by weight of ammonium chloride, 3 parts by weight of the sodium salt of succinic acid ethylene oxide sulfate, 50 parts by weight of finely divided magnesium silicate and 192 parts by weight of water, and this formulation is close to the flame retardant formulation of the present invention. But its pH is immediately after formulation and its weather resistance is very low compared to the examples of the present invention, as is clear from Comparative Examples 7 and 8 below. JP 122560/1984 and 89102/1984 do not give an example of the use of a flame retardant formulation. with a pH of 3 or less.

The pH of the treatment solution greatly affects the weather resistance of the flame retardant when curing takes place at room temperature. This is shown in the accompanying drawing.

The drawing shows graphically the effect of the pH (amount of hydrochloric acid added) of the treatment solution on the amount of residual weight, the amount of phosphorus remaining and the retention of phosphorus content after one period of the simplified weather test. In the drawing, (A) is the amount of weight remaining, (B) is the amount of phosphorus remaining, and (C) is the retention of phosphorus content.

It should be noted that when similar compounds, e.g. (A), (B), (C) and (D) mentioned above are used as flame retardants and cured at room temperature, their level of weather resistance is not as high as in the present invention, even in this case, that the pH of the treatment solution is adjusted to 3 or less. This is apparent from Comparative Examples 14 to 16 below.

In the present invention, the pH of the surface film formed from the treatment solution having a low pH, i.e., up to 3, e.g., 2.5-1.5, is also low, and the strongly acidic film may decompose the wood in contact with the coating material and impair the physical properties of the wood. Thus, red cedar cat-10 topane (Country of Manufacture USA) was coated with a treatment solution (pH 2.0) containing the formulation of Example 1 at an application rate of 250 g / m 2, allowed to cure for 7 days at 25 ° C, treated in an Atlas-type fadeometer at 65 ° C and monitored. changes in the appearance, adhesion, and strength-15 of the coating film every 200 hours (which actually corresponds to one year of sunlight). As the irradiation continued, the color of the film began to change slightly to light brown, but the color damage after 100 hours of irradiation was not very great. In addition, no significant decrease in the adhesion 20 or strength of the coating film layer could be observed. When this coating film was finely ground and 30 times the amount of pure water was added, the pH of the resulting dispersion was 2.8. The chlorine contained in the finely divided powder was quantified and it was found that more than 95% of the chlorine remained in the finely divided powder, from which it spread sparingly in air upon curing at room temperature. This suggests (although the mechanism of action is not known) that the large amount of acid used forms a bond with affinity for a condensation product of a phosphorus-containing flame retardant and melamine resin, e.g., a quaternary ammonium salt structure, and is permanently retained.

A further advantage of the formulation of this invention is that it has a kind of buffering effect which is believed to be due to the affinity of the acidic hardener for water solubility.

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90745 19 to the basicity of its melamine resin. Therefore, the treatment solution based on the formulation of Example 1 irritates the skin mucosa of the person performing the injection less than an aqueous solution containing the same amount of hydrochloric acid (2.5% as HCl; pH 0.05).

Due to the synthetic route, similar flame retardant compounds (A), (B), (C) and (D) contain free formaldehyde, in a 70% solution, e.g. about 1 to 4%. The flame retardant compound of the present invention, on the other hand, does not contain any free formaldehyde. It is able to bind several percent of both the free formaldehyde in the melamine resin and the free formaldehyde formed as the condensation progresses and increases during condensation and reaches its maximum value immediately before the condensation product gels and becomes insoluble in water. For example, the flame retardant of Formulation Example 1 contains 0.6% free formaldehyde immediately prior to formulation, and the flame retardant of Formulation Example 1 (wherein DMPPA is replaced by compound (A), i.e. DMPPA-20 with CH 2 OH) contains 1.2% free formaldehyde. This means that a small amount of ethylene urea or melamine can be added as a formaldehyde scavenger to make the amount of toxic and irritating formaldehyde inhaled by the worker even lower.

The solids content of the melamine resin relative to the flame retardant compound may be freely selected from the range of at least 100 parts by weight, preferably from 100 to 400 parts by weight per 100 parts by weight of the flame retardant compound. If the proportion is less than 150 parts by weight, the weather resistance tends to decrease slightly when cured at room temperature. If the proportion is less than 100 parts by weight, the flame retardant formulation is sticky and its weather resistance is clearly reduced to an unsuitable level. On the other hand, if the application rate is more than 400 parts by weight, the weather resistance is no longer improved, and such an excess of melamine resin is rather detrimental.

20 because the phosphorus content of the cured solid decreases and the result is a decrease in fire resistance.

When the mixing ratio (by weight) of the flame retardant compound and the melamine resin is 100: 210 or close to it, the film obtained by curing the flame retardant formulation at room temperature is transparent and remarkably flexible. However, films prepared in the same manner with the difference that the flame retardant compound of the present invention has been replaced by the above-mentioned compounds (A), (B), 10 (C) and (D) in many cases have fine cracks or foam or are turbid and tend to be brittle. In the weather test, these differences tend to increase. A colorless, transparent, flexible film is also obtained when 3- (diethylphosphonopropioniamine dia) or 3- (diisopropylphosphonopropionamide) is used as the flame retardant compound instead of DMPPA. To compare the appearance of the films after the weather test in the Comparative Examples and Examples of Tables 1 and 2 below, in which wood substrates were coated with these formulations, cured at room temperature and subjected to a 42-cycle (1,000 hour) weather test of the above method in U.S.D.A. According to FPL-1971, the appearance of the treated wood surfaces in the examples was satisfactory, but after the treatment of the wood surfaces of the comparative examples, the coating film came off the wood surfaces or it chalked or cracked. When wood is coated with either melamine resin alone or the flame retardant compound of this invention alone, no charred or swollen expanded layer is formed, even if the coated substrate is heated in contact with the flame 30. Instead, a cured coating film formed of the flame retardant of the present invention, which contains both of these compounds on the surface of wood, easily forms a swollen layer and thus improves fire resistance. It should be noted that when the mixing ratio of the flame retardant solids to the melamine resin solids is

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90745 21 100: 170-230, as is the case with the formulation of Example 1, a carbonized, swollen layer is formed with a maximum expansion ratio.

To further improve weather resistance in this invention, it is preferred to use a moderate amount of penetrant that is stable when the pH does not exceed 3. Examples of the penetrant include dialkyl benzene disulfonate type surfactants (e.g., DAWFAC 2A-1; manufactured by Dow Chemical Company), cationic surfactants and amphoteric fluorocarbon-based surfactants (e.g. MEGAFAC F833; manufactured by Dai-Nippon Ink and Chemicals, Inc.). If the application rate of the penetrant is unnecessarily high, the weather resistance of the fire retardant coating will inevitably decrease, but if the application rate is 15 to about 1% of the treatment solution, it will to some extent promote the penetration of the fire retardant into the wood and improve the weather resistance.

As another additive, it is desirable to use small amounts of antifoam. For example, by using about 0.5-5 20 g / l NOPCO NDW (manufactured by Diamond Shamrock) or a silicone type antifoam, the coating becomes smooth. In addition, 0.5 to 5% by weight, based on the solids, of a polyvinylpyrrolidone having a number average molecular weight of at least 100,000 may be added as a sedimentation inhibitor. In addition to the various additives mentioned above, the flame retardant of the present invention may contain a cracking agent (e.g. inorganic fibers, plasticizers, polymers or water-soluble, high-boiling compounds), acid-resistant dispersed pigments for coloring, perfumes, deodorants, various other flame retardants and anti-caking agents. Other flame retardants that particularly enhance the effectiveness of this invention include, for example, water-insoluble powdered or emulsified phosphorus-containing compounds, organophosphorus-containing compounds, phosphorus- and halogen-containing organic compounds, and organohalogen compounds used either alone or in mixtures. Selected examples include red phosphorus, phosphagen, polyammonium polyphosphate, chlorinated paraffins, chloroalkyl phosphates and polybrominated bisphenols. A suitable amount of each such additive is up to 5% by weight based on the total weight of the flame retardant.

If a wood surface coated with the flame retardant formulation of the present invention and then cured occasionally comes into contact with hard water, e.g., in a rainfall test, with water containing more than 100 ppm calcium oxide (as CaO) and the wood material allows alkaline earth metal absorption of hydroxide or carbonate, it may sometimes be the case that the flame retardancy is impaired even if the cured product of the flame retardant does not dissolve in water but is largely retained. The reason for this is that the phosphorus pentoxide formed during the heating and final decomposition of the DMPPA component in the cured product reacts with the alkaline earth metal hydroxide or carbonate absorbed on the surface of the wood materials to form an alkaline earth metal phosphate which does not act as a flame retardant at all. This reduction in fire resistance can be prevented by adding the above-mentioned halogen and phosphorus-containing organic compounds or organohalogen compounds to the formulation of the present invention. In this way, it is possible to combat the side effects of extinguishing a fire with hard water.

The wood surface is coated with a flame retardant according to the present invention in the form of an aqueous solution or a solution in a water-soluble organic solvent such as methanol, ethanol or isopropanol or a mixture of these organic solvents. The gel time can be significantly increased if the amount of water in the solution is reduced and the amount of alcohol in the solution is increased. For example, the relationship between the solvent composition and the gel time of the formulation of Example 1 is as follows: 23 90745 5 Measurement- Solvent composition Gel time temperature (water / methanol (hours) (° C) by weight 10 40 97/3 about 1 40 85/15 about 5 30 97/3 about 3 30 95/5 about 4 30 90/10 about 7 15 30 85/15 over 9 20 97/3 about 9 This means that both the stability of the formulation, which is dependent on the ambient air temperature, and the gel time , which is suitable for the worker during application, can be easily controlled simply by adjusting the water-soluble alcohol content, which should be noted when the wood surface is coated with the treatment solution after prolonging the gelling time (stability) as described above. the treatment solution is rapidly concentrated, thereby accelerating the curing reaction.

In the preferred coating method of the present invention, a spray gun, paint roller or brush is used, or the wood substrate is immersed in a treatment solution. When coating the surface of the wood material, the application rate of the coating is at least 100 g / m 2, preferably 150 to 300 g / m 2, based on the solids. The solids content of the coating material is preferably about 60%. If the concentration is higher, e.g. more than 70%, the flowability of the treatment solution deteriorates and it is difficult to obtain a uniform coating. If the concentration is adjusted to 50% or less, the treatment-40 solution will penetrate too much into the internal structure of the wood material 24 with some wood materials, such as radially sawn veneer. The treatment solution thus penetrates too deep into the wood and the fire resistance is reduced.

When the flame retardant coating formed from the formulation of the present invention is applied to a wood material containing less than 5% moisture and which is highly porous due to its prolonged appearance, it is desirable to pretreat the surface of the wood material by spraying or brushing it to wet the surface. With this surface of such wood material, effective fire protection is achieved even if the amount of treatment solution is relatively small, e.g. up to 150 g / m 2. In such a case, it is desirable to coat after the water-treated wood substrate has been allowed to stand for some time and the water has diffused and penetrated evenly. Otherwise, when the wood substrate contains too much water, the coated fire retardant film may peel off or collapse. The water content of the material to be coated is thus preferably in the range of 8 to 30%. 20 When this wetting treatment is properly performed before coating, it is sometimes possible to prevent the substrate from twisting by coating.

Other methods of treating a wood substrate with a flame retardant according to the present invention include, for example, (I) a vacuum method, (II) a pressure method and (III) a vacuum / pressure method. In practice, the easiest way is as follows: The wood material is placed in an acid-resistant autoclave and the flame retardant solution is added to it so that the wood substrate is completely below the surface of the solution and there is air space at the top of the vessel. When a vacuum is sucked into the top 30 under predetermined conditions, the air in the internal structure of the wood material is removed and, depending on the magnitude of the vacuum (negative pressure), equilibrium is reached after a predetermined time. The atmospheric pressure is then allowed to return to normal pressure and the wood material is allowed to stand in solution for as long as the vacuum has passed.

II

90745 25 for childbirth. As a result, the wood material is subjected to a positive pressure approximately equal to the vacuum, allowing a considerable amount of flame retardant to penetrate into the wood material and providing a fire resistance that is longer than when coated. If the pressure is increased at this stage, the saturation of the wood material with the flame retardant will further increase.

Numerous applications can be found for the flame retardant formulation of this invention, e.g. in almost all treatments of wood materials 10 with a flame retardant that require weather resistance, i.e. in the treatment of weather-sensitive wood materials such as roofing shingles and shingles (made of eg pine or cedar), window frames, doors, stairs, fences, porches, trusses, steps, , exterior decorations, handrails, pergolas, columns, interior materials for ships or bathrooms, door frames for livestock pens and Japanese-style houses, timber, wooden packing boxes for export, and wood materials used in altars and temples. The present invention is, of course, effectively applicable to wood materials used indoors, such as ceilings, floors, floorboards, interior wall materials, furniture, Japanese house sliding door frames, moldings, interior doors, and columns. There are no particular limitations on the quality of the wood materials to which the method of the present invention can be effectively applied, and the present invention can make almost all natural wood materials fire resistant. However, a sufficient flame retardant effect cannot be achieved or can be achieved only at the expense of weather resistance on the surface of sheets with a hydrophobic surface layer. These include unsaturated polyester resin coated decorative boards, plywood boards having a highly hydrophobic surface and containing large amounts of phenolic resins, melamine resin, urea resin or the like and cured by heating under pressure, and natural wood materials, which are hydrogenated natural wood materials.

The flame retardant compounds of this invention, e.g., DMPPA, have very low oral toxicity, i.e., an LD50 (rat) of at least 5,000 mg / kg, and are not mutagenic. Because melamine resin contains a small amount of formaldehyde, it slightly irritates the living body. In the above-mentioned coating embodiments, conventional conceptual measures prevent irritation or adverse health effects on the human body. Since the flame retardant solid of the present invention releases some formaldehyde over a long period of time, it also acts as a long-acting insecticide or antiseptic in weatherproof wood materials. These properties are particularly good in wood board, both surfaces of which are impregnated with palones. In particular, when a small amount, e.g. up to 10 g / l of thiourea, is added, the insecticidal and antiseptic effect is long-lasting and a considerable binding of the free formaldehyde and some improvement in the flame retardancy can be expected.

The following examples illustrate the present invention.

Comparative Examples 1 to 15 and Examples 1 to 9 In each run, a film cured at room temperature based on the flame retardant formulations of Tables 1 and 2 was prepared and subjected to Sections 1, 6 and 20 of the above-mentioned simplified film method as shown in these tables. The amount of residual weight (A), the amount of residual phosphorus (B) and the retention of phosphorus content (C) were determined. The abbreviations used in the tables for flame retardants and melamine resin are as above. In the tables, the concentration of the acid catalyst is as a percentage by weight, based on the total solids weight of the flame retardant-35 compound and the melamine resin.

Il 90745 27 The fire resistance test of these tables after a 1,000 hour weather test was performed as follows: Test covers made from roofing shingles obtained from conventional red cedar growing in the United States, which were the test of the Red Cedae Shingle & Handsplit Bureau, U.S.A. were coated with a spray gun using each formulation at an application rate of 250 g / m 2. The coating was allowed to cure for 7 days at about 20 ° C and then allowed to undergo the above method in U.S.D.A. 42 cycles (1,000 hours) of the weather test according to FPL-10 1971 and dried in a room with a humidity of 30% and a temperature of 27 ° C until a constant weight was reached. A fire test in accordance with ASTM E-108 80a, Class C, was then performed five times for each roofing sheet. Fires that did not penetrate the back surface of the available portion of the roofing sheet but extinguished spontaneously were judged acceptable.

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Vertailuesimerkki_1_2_3_4

The appearance of the film is transparent through-transparent through-transparent. . cold rolling mill

Film weight (250 g / m2)

The appearance of the film after a single weather cracking cracking cracking after the test period.

Remaining weight 63.4 68.0 67.0 69.8 10% (%) Remaining phosphorus 21.6 30.0 29.1 21.4% (%)

Phosphorus content retained- 13.7 20.6 19.3 19.9 (%) 15 Appearance of the membrane after six weathering - - adjusted after the test period Remaining pressure- 60.3 - - - (%) Remaining phosphorus - 21.4 20 amount (%)

Phosphorus retention - 12.9 - retention (%)

Fire resistance of wood material after 1000 hours of weather test 25

Number of pieces with grade 0 0 0 0 "acceptable"

Number of pieces rating- 5 555 with "rejected" 3 0 Review rejected rejected rejected rejected

II

90745

Table 1. (continued) 31

Comparative example_ 5_6_7_§_

The appearance of the film is transparent to transparent to transparent

Film weight (250 g / m 2) 250 250 250 250

Appearance of the film after one transparent transparent transparent-through-weather test period strong strong Remaining weight (%) 78.0 77.4 70.5 69.8 Remaining phosphorus 43.0 56.6 46.6 33.7 10 r ( %)

Phosphorus content retained - 34.0 43.8 32.9 23.5 m (%)

Appearance of the film after six weather-transparent transparent after transparent-through-test periods strong hard 15 Remaining weight 69.3 68.2 65.0 69.8 rä (%) Remaining phosphorus 49.2 64.1 47.0 33 .7 amount (%)

Phosphorus retention - 34.1 43.7 30.7 23.5 20 retention (%)

Fire resistance of wood material after 1000 hours of weather testing

Number of pieces with these grades "acceptable" 2 3 2 1

Number of pieces rated "rejected" 3234

Review rejected rejected rejected rejected

Table 1 (continued)

Vertailuesimerkki_9_10_11_12

The appearance of the film is cloudy, light-through-transparent-celt. good good 2

Film weight (250 g / m)

The appearance of the film after one weather-permeable light-through-transparent yellow. strong strong Remaining weight (%) 66.1 67.9 67.1 71.5 10 Remaining phosphorus content 26.6 51.9 38.9 38.7% (%)

Phosphorus retention 17.6 35.2 26.1 27.7 retention (%)

Film appearance after six - - 15 weather test periods Remaining weight - - (%) Remaining phosphorus - - (%) 20 Retention of phosphorus content - - (%)

Fire resistance of wood material after 1000 hours weather test 25 Number of pieces with grade 0 2 12 "acceptable"

Number of pieces worth 5,343 with the word "abandoned"

Review rejected rejected rejected rejected

II

Table 2 33 90745

Formulate Similar, not according to the invention • _formylates_ 5 Comparative example (EE) or pre- PE13 EE 14 EE15 mark (E) _

Fonulate (w / w / 1000 wt) DMPPA-CH2CH (70%) 275 275 10 DMPPA-DMPPA (70%) 275 DMPPA (70%) MMM (hexamethylol type) (70 "%) 580 580 MMM ( trimethylol type) (70 ~%) 580 ME3AFAC F833 (penetrant) 15 15 15 15 20% hydrochloric acid 120 120 120

Water 10 10 10

Total solids content (%)

Hydrochloric acid content (% of solid 4.0 4.0 4.0 substances) 20 Ratio of flame retardant solids to 1 / 2.1 1 / 2.1 1 / 2.1 melamine resin solids pH of treatment solution 2.2 2.3 2.5

Table 2 (continued)

Formulation Invention (using varying amounts of HCl) Comparative Example (RE) or

Example (E) _E 1 E 2 E 3 E 4 E 5

Formulation (parts by weight / 1000 parts by weight) dmppa-ch2cm (70-%) 10 DMPPA-DMPPA (70-%) DMPPA (70-%) 275 275 275 275 275 MMM (hexamethylol type) 580 580 580 5G9 (70- %) MMM (trimethylol type) 15 (70%) 580 MBGAFAC F833 (penetrant) 15 15 15 15 14 20% hydrochloric acid 120 90 90 90 147

Water 10 40 40 40 20 Total solids content - 62.4 61.8 61.8 61.8 61.8 mouth (%)

Hydrochloric acid content (% of solids)

Ratio of flame retardant solids 1 / 2.1 1 / 2.1 1 / 2.1 1 / 2.1 1 / 2.1 25 to melamine resin solids Treatment solution pH 2.4 2.5 2.5 2.5 1.6 li

Table 2 (continued) 35 90745

Invention (using varying ratios of flame retardant to melamine resin)

Comparative Example (RE) or Example (E) _E_6_E_7_EJ3_E 9

Formulation (parts by weight / 1000 parts by weight io dmppa-ch2oh (70-%) DMPPA-DMPPA (70 "%) DMPPA (70-%) 305 342 251 231 MMM (hexamethylol type) 550 513 604 624 (70-%) 15 mmm (trimethylol type) (70%) MEGAFAC F833 (tracer) 15 15 15 15 20% hydrochloric acid 120 120 120 120

Water 10 10 10 10 20 Total solids content - 62.4 62.4 62.4 62.4 mouth (%)

Hydrochloric acid content 4.0 4.0 4.0 4.0 (% solids)

Flame retardant solids - 1 / 1.8 1 / 1.5 1 / 2.4 1 / 2.7 25 den and melandin resin solids ratio Treatment solution pH 2.1 2.1 2.1 2.2 2.2

Table 2 (continued)

Comparative example (RE) or RE 13 RE 14 RE 15 example (E) _ 5 Appearance of the film before the weather test rub clear slightly cloudy cloudy 2

Film weight (g / m)

Appearance of the film after one meteorological test rubbing cloudy period cloudy 10 Remaining weight (%) 63.6 69.7 68.0 after one meteorological test period Remaining phosphorus amount (%) 47 g ^ ^ 20 3 after one weathering period

Phosphorus retention 30.5 38.0 20.6 15 (%) after one weather trial period

Film appearance after 20 weather test cycles - Remaining weight (%) after 20 weather test cycles 20 Remaining phosphorus content (%) after 20 weather test cycles

Phosphorus retention - - - (%) after 20 weather test periods Fire resistance of wood material after 25 1000 hour weather test

Number of pieces with a rating of 2 2 1 "acceptable"

Number of pieces with a rating of 3 3 4 "rejected" 30 Review rejected rejected rejected

II

Table 2 (continued) 37 90745

Comparative example (RE) or pre- E 1 E 2 E 3 character (E) _ 5 Film appearance before weather test clear clear clear

Film weight (g / m2)

Appearance of the film after one weather test period - slightly clear clear after cloudy Remaining weight (%) total after 75.3 78.9 80.5 10 den weather test period Remaining phosphorus amount (%) 69.8 78.9 85.9 after one weather test period

Phosphorus retention 52.6 62.3 69.1 (%) after one weather test period 15 Film appearance 20 weather test periods - after clear brightness Remaining weight (%) After 20 weather test periods - 71.7 72.3 Remaining phosphorus amount 20 (%) ) After 20 weather test periods - 71.8 90.3

Phosphorus retention - 51.8 65.3 m (%) after 20 weather test periods

Fire resistance of wood material after 25 1000 hours weather test

Number of pieces with a rating of 55 5 "acceptable"

Number of pieces rating- 00 0 la "rejected" 3 0 Review pass- pass- acceptable flammable

Table 2 (continued)

Comparative example (KE) or pre- E 4 E 5 E 6 character (E) _ 5 Film appearance before weather test clear clear clear

Film weight (g / m2)

Appearance of the film after one weather test period- clear clear clear word Remaining weight (%) after 80.5 75.9 77.7 10 den weather test period Remaining phosphorus (%) after 86.7 90.8 84.7 den weather test period after

Phosphorus retention (%) 69.8 68.7 65.8 after one weather test period 15 Film appearance 20 weather test cycle after bright clear clear Remaining weight (%) 72.8 68.6 70.8 After 20 weather test periods Remaining phosphorus (%) ) 90.3 88.8 87.5 20 20 after the weather trial period

Phosphorus retention 65.7 62.8 62.0 (%) after 20 weather test periods Fire resistance of wood material after 1000 hour weather test 25 Number of pieces with a rating of 5 5 5 "acceptable"

Number of pieces with a rating of 0 0 0 "abandoned"

Rating Approve Approve 3 0 Flammable Flammable Flammable ii

Table 2 (continued) 39 90745

Comparative example (RE) or pre- E 7 E 8 E 9 character (E) _ 5 Film appearance before weather test clear clear clear

Film weight (g / m2)

Film appearance after one weather test period clear clear clear period Remaining weight (%) 75.0 82.4 83.1 10 after one weather test period Remaining phosphorus amount (%) 84.4 86.9 87.1 after one weather test period

Phosphorus retention 63.3 71.6 72.3 (%) after one weather test period 15 Film appearance 20 weather test period - clear clear clear weight remaining (%) 67.5 75.5 75.8 after 20 weather test periods Remaining phosphorus content ( %) After 87.3 88.1 88.3 20 20 weather trial period

Phosphorus retention 58.9 66.5 66.9 (%) after 20 weather test periods Fire resistance of wood material after 1000 hour weather test 25 Number of pieces with a rating of 5 5 5 "acceptable"

Number of pieces with a rating of 000 "rejected"

Rating pass- pass- pass 3 0 igniting igniting igniting 40

Examples 10 to 12 and Comparative Example 16 Six pine boards (thickness 4 mm, length 300 mm, width 200 mm and moisture content 9.2%) were prepared and the boards were immersed in each of the following three treatment-5 solutions. The immersed plates were allowed to hang in air by attaching each sample to its upper end to remove excess solution so that the amount of flame retardant applied to each surface was 1.50 g calculated as solids. The coating was cured by standing the plates for 7 days at 10 ° C. The plates were then allowed to undergo 42 cycles of the weather test over 1,000 hours by the method of U.S.D.A. FPL-1971 conditions and dried in a desiccator at 30% constant weight. The dried sheets were subjected to a fire resistance test in which the sheets were exposed to a flame for 3 minutes according to method JIS 1322, which is applicable to testing the non-combustibility of thin building materials. The results are shown in Table 3.

Table 3 41 90745

Comparative example (RE) or pre- E10 E11 E12 RE16 character (E) _________

Fonulate (w / w) 5 70% aqueous DMPPA 220 - - Unprocessed 70% 3- (diethylphosphono) propionamide aqueous solution (DEPPA) - 254 70% 3- (diisopropylphosphono) - 10 propionamide aqueous solution (DIPPPA) - - 288 70% methylated netylol melamine 464 464 464

Dialkyl benzene disulfonate 5 5 5 20% hydrochloric acid (as HCl) 100 100 100

Defoamer (NOPCO NEW) 11 1 15 Methanol 25 24 22

Total_815_ £ 48_880_ Solids content of treatment solution 61.8 62.2 62.6 content (%) __

Fire resistance before weather test (flame 3 min) 20 Carbonation distance (suction) 42 63 78 complete combustion

After the flamethrower (seconds) 01 4

After glow time (minutes) 0 1 (seconds - 8 (sevens) municipalities)

Rating category 1 category 2 category 2

Fire resistance after weather test (flame 3 min)

Carbonation distance (mm) 48 78 107 complete combustion

After the flamethrower (seconds) 0 3 15

After glow time (minutes) 0 5 (seconds 33 (seconds)) 35 Rating class 1 class 2 class 3 (*) All aqueous solutions of DMPPA, DEPPA and DIPPPA had a phosphorus content of about 12%.

42

Example 13 and Comparative Example 17 Four square plates (side length 3,000 mm and thickness 8 mm) were prepared from Japanese cypress. The other side of the two sheets was coated by brushing with a treatment solution prepared by adding melamine powder as a formaldehyde binder to the formate of Example 1 at a solids application rate of 250 g / m 2 and cured for 2 days at 20 ° C and then for 5 hours at 60 ° C. One untreated plate was then added and 10 plates were allowed to undergo 42 cycles (1,000 hours) of weathering according to the method of U.S.D.A. FPL-1971 conditions and dried in a desiccator at 30% humidity to constant weight (water content 8.2 to 8.5%). The bunsen lamp flame was then contacted with the plates by heating the center of each of the 15 horizontal plates for 3 minutes at 1,050 to 1,100 ° C. The results are shown in Table 4.

Table 4 20 Example 13 Comparative _example17

Flame retardant coating- The method described above- the method of operation

Fire resistance before the weather test 25 At the time when the heating was formed, a single layer of flame that came into contact with the flame and a completely foamy and completely swollen layer flame at the point of contact.

Number of flame contacts before the flame burst the sample 7

Fire resistance after weather test 35

At the time of heating- Same as before- Ignition was performed by a single flame contact weather test and complete combustion 40 Number of flame contacts before the flame burst sample 6 li 90745 43

Example 14

Example 6 was repeated except that the flame retardant (pH 2.1) was prepared using DMPPA, which was purified by crystallization five times from methanol to a purity of more than 99%.

As a result, the retention of phosphorus content was as high as 94.2% and 90.6% after 1 and 20 periods of the weather test, respectively.

Example 15 The same flame retardant treatment was performed as in Example 6 using a flame retardant (pH 2.1) obtained by adding 40 parts by weight of tetrabromobisphenol A and 5 parts by weight of polyvinylpyrrolidone (number average molecular weight 360,000) as a dispersant. Thus, the treated sample was subjected to a weather test using water containing 130 ppm CaO. The number of acceptable samples in the fire test was 5.

Example 16

A cedar plate (thickness 10 mm and moisture content 12%) was placed in a glass pressure vessel and floating was prevented with a tool.

Flame retardant (pH 2.4) consisting of 220 parts by weight of a 70% ethanol / water solution of DMPPA (50:50 by weight), 460 parts by weight of a 70% aqueous solution of methylated methylol melamine-25 amine, 3% by weight part of NOIGEN ET-95 (nonionic surfactant; manufactured by Daii-chi Kogyo Seiyaku KK), 100 parts by weight of 20% hydrochloric acid and 217 parts of water, were added so that the cedar plate was completely there was 30 air spaces in the liquid and at the top of the vessel. A vacuum of 30 mmHg was aspirated over about 20 minutes using a valve at the top. There was considerable foaming at first, but at the end foaming ceased. The valve at the top was opened and the pressure returned to normal pressure. After standing for 30 minutes and then the cedar plate 35 was removed and dried for 7 days at 25-33 ° C.

44 The treated cedar plate contained an average of 110 g / m 2 of flame retardant solids over its entire surface and the impregnation had penetrated to a depth of about 2 mm. The treated cedar plate, either as such or after about one year of weather test 5 outdoors in Takaishi City, Osaka-fu, Japan, and after drying to a moisture content of 8 to 12%, could not be burned continuously in an ignition test using a bunsen lamp.

Il

Claims (6)

1. Each S / P r 3 / n · R 2 -O n CH 2 CHCONH 2 wherein each R x and R 2 is an alkyl group containing 1-3 carbon atoms and R 3 is a hydrogen atom or a methyl group, and calculated on solid at least 100 parts by weight of a water-soluble melamine resin, characterized in that the pH of the fire protection agent is not higher than 3. 48 1. A fire protection agent in the form of an aqueous solution for wood material, which means as a main component calculated on solid contains 100 parts by weight of a water-soluble 3- (dialkylphosphono) propionamide of the general formula R, -0 0 H, ✓ \ » Wherein each Rx and R2 is an alkyl group containing 1-3 carbon atoms and R3 is a hydrogen atom or a methyl group, and calculated on a solid at least 100 parts by weight of a water-soluble melamine resin, characterized in that its pH not higher than 3. 2. Fire retardant according to claim 1, characterized in that the amount of water-soluble melamine resin is 100 to 400 parts by weight based on solids. 3. Fire-resistant wood material prepared by treating wood material with a fire-retardant in the form of an aqueous solution containing, as the main constituents of solid, 100 parts by weight of a water-soluble 3- (dialkylphosphono) propionamide of the general formula R 4. Fire-resistant wood material according to claim 3, characterized in that the surface of the wood material has been treated with the fire protection agent. 5. Fire-resistant wood material according to Claim 3, 5, characterized in that the wood material is coated with the fire protection agent in a coating amount of at least 100 g / m 2 calculated on a solid. 6. Fire-resistant wood material according to claim 3, characterized in that the wood material is impregnated with the fire protection agent. Il