JPS5847520B2 - Cellulose cellulose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for treating cellulosic materials with heat and flame resistance using ammonium polyphosphate.

In particular, the present invention provides excellent heat-resistant and flame-retardant effects by impregnating or surface-treating a cellulose-based material with a heated aqueous solution of ammonium polyphosphate in which urea, dicyandiamide, borax, and ammonium borofluoride coexist, and then drying the material. This invention relates to a flame retardant treatment method.

The present inventors have already disclosed in JP-A No. 49-74768 a method for flame-retardant treatment of cellulose materials, polyvinyl alcohol materials, and urethane materials using polyimide ammonium phosphate, which is substantially poorly soluble at room temperature. I made it.

In other words, the method described in the above-mentioned patent publication is to prepare ammonium polyphosphate, which is substantially poorly soluble in water at room temperature, into an aqueous solution heated at 50° C. or higher, and impregnate a cellulose material or the like with this solution, or to perform a surface treatment using the solution. This is an effective flame retardant treatment method in which ammonium polyphosphate is uniformly penetrated into the material and then dried.

This method has various advantages such as improved weather resistance by using ammonium polyphosphate as a flame retardant, which has significantly superior moisture resistance and water resistance compared to orthorin, and uniform flame retardancy of the material through impregnation treatment. However, in terms of heat resistance, particularly in preventing discoloration of cellulose-based materials during heat treatment during secondary processing, a new level of performance was required.

On the other hand, considerable research and consideration has been made to improve the heat resistance of cellulosic materials, especially paper.

Among these, adding amines during the paper manufacturing process was an effective means, published in the Paper and Pulp Technology Times in 1923.
It is described on page 4 of the November 7 issue.

However, the above-mentioned known documents only provide an overview of heat-resistant processing, and measure flame retardancy from the aspect of strength, and do not mention thermal discoloration at all, and do not mention the use of amines to prevent thermal discoloration. It has not been clarified whether it has any effect or not.

As a result of various studies on heat discoloration and flame retardant treatment methods for cellulose-based materials using ammonium phosphate, the present inventors found that simply adding an amine compound with a high content of amino groups (-NH2) I learned that this is not an effective means to achieve the above objective.

For example, as an amine compound added to a heated aqueous solution of ammonium polyphosphate, hexamethylenetetramine (commonly known as urotropin), which has a high amine content, exhibits excellent heat resistance to discoloration, but greatly reduces flame retardant performance.

In addition, adding urea alone does not show very good heat discoloration resistance, and the combination of hexamethylenetetramine and urea has excellent heat discoloration resistance and flame retardant performance, but it produces a precipitate of methylene urea, making it unsuitable as an impregnating liquid. It is.

Furthermore, substances such as methylamine, ethylamine, and ethanolamine tend to color the applied material after impregnation.

Further, although dicyandiamide has a certain degree of excellent heat discoloration resistance, its solubility is low and it is impossible to prepare a solution with a concentration sufficient to exhibit sufficient heat discoloration resistance.

In order to eliminate these drawbacks of various amine compounds, the present inventors have repeatedly studied flame retardant treatment methods that provide even higher heat discoloration resistance and heat strength deterioration resistance (bending resistance), and as a result, PoIJ IJ The inventors have found that when urea, dicyandiamide, borax, ammonium borofluoride, etc. coexist in a heated aqueous solution of ammonium fluoride, extremely excellent heat resistance is exhibited, and the method of the present invention has been achieved.

That is, the present invention provides a method for using poIJ that is substantially poorly soluble in water at room temperature.
A heated aqueous solution of IJ ammonium phosphate at 50°C or above is made into a solution in which urea, dicyandiamide, borax and ammonium borofluoride coexist, and cellulose-based materials are impregnated or surface treated to allow the chemical solution to penetrate into the interior of the material. This is an effective heat-resistant and flame-retardant treatment method, which consists of drying and then drying.

According to the present invention, it is possible to make the applied material flame retardant while maintaining its poorly soluble property without changing the degree of polymerization of ammonium polyphosphate, so water resistance and moisture resistance are good.

Furthermore, since the heat discoloration resistance has been greatly improved, the degree of heat discoloration of the treated material is extremely small even when heated during secondary processing.

Furthermore, it has excellent not only heat discoloration resistance but also heat resistance to strength deterioration (folding resistance), so it can be used for various purposes.

Furthermore, since ammonium polyphosphate does not rust metals like other ammonium phosphates, materials treated by this method can also be used in applications that come into contact with metals.

The poorly water-soluble ammonium phosphate used in the present invention is generally ammonium orthophosphate and urea, orthophosphoric acid and urea, phosphoric anhydride and ammonia, urea phosphate, condensed phosphoric acid and urea, or A polymeric phosphorus compound obtained by heating and condensing one or more suitable combinations of raw materials having a phosphoric acid source, a condensing agent, and an ammonia source in combination such as ammonium orthophosphate, urea, phosphoric anhydride, and ammonia. It is.

For example, the general formula H(n1m)+2(NH4)mPnO3n
+1 (in the formula, n is an integer of about 10 or more, m/n is about 0
．． 7 to 1.1, where m is approximately equal to n + 2), and the like is a typical example.

Also, poorly soluble in water means that 10 g of ammonium polyphosphate is 1
When added to 00CC water at 25℃, the solubility is approximately 22
/means 100cc or less of water.

The impregnation method used in the method of the present invention may be a normal pressure impregnation method, and in order to further increase the impregnation ability, a vacuum impregnation method or a pressure impregnation method is effectively used.

Examples of surface treatment methods include spraying, coating, and treatment using a size press in the paper industry.

Drying of the material after impregnation may be appropriately selected depending on the type, physical properties, shape, etc. of the material, such as a general hot air dryer,
Drum-type dryers and vacuum heating drying are effectively used to improve the drying capacity.

The thus obtained flame-retardant treated material has sufficient water resistance under normal usage conditions, but if higher water resistance and washing resistance are required, it can be treated simultaneously with the method of the present invention. Alternatively, a conventionally known treatment method such as a resin processing method may be used in combination as the two-stage treatment.

The cellulosic materials to be treated in the method of the present invention refer to a wide variety of materials such as paper products, cotton, cloth, wood products, and rayon, which can be obtained from natural cellulose as a raw material, and have a natural cellulose content of 30% or more.

Therefore, it may be only natural cellulose, or it may contain non-cellulose materials such as acrylonitrile, polyester, polyamide, etc. in addition to cellulose.

In the method of the present invention, the temperature at which the heated aqueous solution of poorly water-soluble polyammonium chloride is adjusted is desirably 50°C or higher, preferably 60 to 90°C.

If the adjustment temperature is lower than this range, the dissolution of ammonium polyphosphate in water will not be sufficient, and the treatment liquid will become a slurry, and the surface of the material will be covered with ammonium polyphosphate during impregnation, resulting in a decrease in the impregnation rate. No improvement can be expected, and impregnation tends to be uneven.

Furthermore, if the adjustment temperature is higher than this range, ammonium polyphosphate will partially undergo hydrolysis, and the proportion of poorly soluble ammonium polyphosphate in the material after impregnation and drying will decrease, which is not preferable.

The additives urea, dicyandiamide, borax, and ammonium borofluoride may be added to the aqueous solution of ammonium polyphosphate, or may be mixed at the same time when preparing the aqueous solution of ammonium polyphosphate.

In particular, since dicyandiamide has a low solubility, it is preferable to add it when preparing a heated aqueous solution.

In the method of the present invention, the balance between the flame retardant polyammonium phosphate and various additives is relatively important.

According to the measurement results of the present inventors, JIS-Z was used as the test method.
-2150, in order to pass flame retardant class 1, when treating paper as a material, it is necessary to deposit 5 parts by weight or more of ammonium polyphosphate per 100 parts by weight of paper stock. It became clear.

In the method of the present invention, the ratio of ammonium phosphate, urea, dicyandiamide, borax, and ammonium borofluoride in the impregnation solution is 100/2 to 400/2.
0.5-200/0.5-200/1-400 (weight ratio), preferably 100/5-300/1-1
A ratio of 00/2 to 200 is desirable.

If the amount of other chemicals added to ammonium polyphosphate is less than this range, heat discoloration resistance and folding durability will be poor, and if it is more than this range, the concentration of other chemicals in the solids concentration of the impregnating liquid will be poor. The relative proportion of IJ ammonium phosphate decreases, and attempting to deposit the necessary ammonium ponophosphate in the adapted material to meet the desired flame retardant performance results in the deposition of more other agents than necessary, making it economically uneconomical. In addition, the texture of the final product will be damaged.

In addition, the concentration of the aqueous solution of ammonium polyphosphate used to treat the material may be appropriately selected depending on the immersion time of the material in the impregnating solution and the surface treatment time, but it is generally 1 to 35% by weight.
Adjusted within the range.

If the concentration is below this level, the amount of impregnation into the material will be low or the processing time will be long.

Further, if the concentration exceeds this level, the treatment liquid becomes a slurry state, and no improvement in the impregnation rate can be expected, and the loss of ammonium polyphosphate increases.

As described above, in the method of the present invention, ammonium polyphosphate, which is substantially poorly soluble in water at room temperature, is heated to an aqueous solution at a temperature of 50°C or higher, and a solution is prepared in which urea and dicyandiamide, as well as borax and ammonium borofluoride are made to coexist. This is a flame retardant treatment method that imparts heat resistance by impregnating cellulose materials with cellulose-based materials or by surface treating them with this solution and then drying. According to this method, the material has uniform heat resistance and flame resistance. It is an efficient flame retardant treatment method that can maintain flame retardant performance for a long period of time because it has excellent water resistance and moisture resistance.

The method of the present invention will be explained in more detail below with reference to Examples, but the method of the present invention is not limited to these Examples, and various improvements can be made within the scope of the constituent requirements. It is.

Comparative Example 1 80 parts by weight of ammonium oxide (N14.10% by weight, P20,7 2.20% by weight, dissolution rate 15.5%) which is substantially poorly soluble in water at room temperature When the mixture was mixed and stirred at 70° C. for 2 hours, an almost transparent aqueous solution of ammonium polyphosphate was obtained.

Predetermined amounts (shown in Table 1) of urea and dicyandiamide were added to this aqueous solution, and the mixture was stirred to completely dissolve it, thereby preparing an impregnating liquid.

The concentration of this impregnating liquid was too high if used as it was, and the amount of the drug adhering to the impregnating liquid would be too large, so the cellulose paper sheet was diluted with water as appropriate and impregnated with the drug.

After the impregnated paper sheet was air-dried, moisture was sufficiently dried in a hot air dryer at 80°C.

Table 1 shows the amount of chemicals adhered to the paper sheet and the results of various physical property tests.

The combustion test (charring length) is based on JIS-Z-2150 (4).
5° method), the degree of thermal discoloration after heat treatment was measured using a whiteness meter (manufactured by Toyo Kagaku Sangyo Co., Ltd.), and the heat resistance strength was measured by an MIT type folding strength tester (manufactured by Toyo Seiki Co., Ltd.). .

The heat treatment conditions are as follows: A hot air dryer is used, and the treatment temperature is 2.
The temperature was 00'C and the standing time was 3 minutes.

As shown in Table 1, it can be seen that by adding urea and dicyandiamide to an aqueous solution of ammonium polyphosphate, heat discoloration resistance and bending strength are improved without reducing flame retardant performance.

Example 1 85 parts by weight of water was added to 15 parts by weight of the same ammonium polyphosphate used in Comparative Example 1, and the mixture was mixed and stirred at 80°C for 1 hour to form an almost transparent ammonium polyphosphate aqueous solution. Obtained.

To this aqueous solution, urea, dicyandiamide, borax, and ammonium borofluoride were added in quantitative quantities (shown in Table 2), mixed, stirred, and dissolved to obtain an impregnating solution.

The same cellulose paper sheet used in Example 1 was immersed in this impregnating solution diluted with water as appropriate to impregnate it with the drug.

Table 2 shows the amount of chemicals adhered to the paper sheet and the results of various physical property tests.

Note that each test method and conditions are the same as in Example 1.

As shown in Table 2, it can be seen that the heat discoloration resistance and folding strength are further improved compared to those in Table 1.

Claims (1)

[Claims] 1. Ammonium phosphate, which is substantially poorly soluble in water at room temperature, is heated to an aqueous solution at 50°C or higher, and urea,
A heat-resistant and flame-retardant treatment method for a cellulose-based material, which comprises impregnating the cellulose-based material with a solution containing dicyandiamide, borax, and ammonium fluoroborate, or surface-treating the material with the solution, and then drying the material.