JPS61243889A - Flame retardant in aqueous solution form - Google Patents

Abstract

PURPOSE:To obtain a flame retardant in an aq. soln. form improved with respect to thermal stability without sacrificing flameproofness and rustproofness, by adding boric acid or borax to a specific aq. guanidine soln. CONSTITUTION:NH4H2PO4, dicyandiamine and urea are reacted in a molten state with each other in a molar ratio of 1:0.5-1.5:0.1-1 in an ammonia atmosphere to obtain a condensed guanidine phosphate. 1-10wt% boric acid or borax is added to an aq. soln. containing 10-60wt% condensed guanidine phosphate to obtain the titled flame retardant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Technology] The present invention relates to a condensed guanidine phosphate aqueous flame retardant. More specifically, the flame retardant is obtained by adding 1 to 15% by weight of boric acid or 1 to 10% by weight of borax to an aqueous solution of condensed guanidine phosphate.

[Conventional technology]

It is well known that guanidine salts are effective flame retardants for flame retardant treatment of paper products or wood laminates that are cellulosic materials, or textile products obtained from cellulose materials such as cotton cloth or rayon as starting materials. It is being For this purpose, guanidine phosphate,
Guanidine sulfamate is in practical use. However, these guanidine salt-based flame retardants are still not sufficient in terms of thermal stability or flame retardancy.

Among these, guanidine phosphate ((H2N-C:NH
-NH2)・H3P 04 or (H2N-C:NH
-NH2)2・Hs P04] has poor thermal stability when used in paper, and the paper is particularly discolored during heat treatment during secondary processing, so its practical use is limited.
Guanidine sulfamate tends to be preferred over this one. However, guanidine sulfamate mainly has the following two drawbacks.

The first is that this material has a lower flame retardant performance, about half that of guanidine phosphate, so in order to obtain a processed product with sufficient flame retardant effect, it is necessary to deposit approximately 25% or more by weight. This has an undesirable effect on the physical properties of the flame-retardant product thus obtained (for example, hygroscopicity). The second drawback is that guanidine sulfamate does not have the antirust properties (see below) that phosphates in general (including guanidine phosphate) have.

On the other hand, as methods for producing condensed guanidine phosphoric acid salts, for example, the following methods are known. That is, (1) a method in which dicyandiamide and ammonium dihydrogen phosphate are reacted by heating at 170 to 220°C in a molar ratio of 1:1.8 to 2 in a sealed pressurized container (Japanese Patent Publication No. 52-29729), or (2) a method in which the degree of condensation n is In this method, 20 or more condensed phosphoric acid compounds (which are sparingly soluble or insoluble in water) are reacted with a guanidine salt such as guanidine phosphate or guanidine carbonate to obtain a water-soluble condensed guanidine phosphate.

However, according to follow-up studies by the present inventors, the condensed guanidine phosphoric acid salts obtained by these methods all have insufficient thermal stability, and are not suitable for conventional methods (JIS P-8
According to the measurement results of 123 Paper and Pulp Hunter Whiteness Test Method), the Hunter whiteness after heat treatment at 200°C for 3 minutes is 10% or less, and the minimum standard for the whiteness of flame-retardant treated paper as a product is usually Since the whiteness is about 50%, a flame retardant that can only obtain a whiteness of 10% or less loses its commercial value.

[Purpose of the invention]

In view of the above-mentioned problems of known techniques related to aqueous flame retardants, the present inventors have proposed that while maintaining the excellent flame retardant performance and rust prevention properties that are the advantages of guanidine phosphate, the above-mentioned thermal stability We conducted intensive research to improve the deficiencies.

As a result, a condensed guanidine phosphate salt (preferably (described below)
By adding and dissolving an appropriate amount of boric acid or borax into an aqueous solution of the reaction product produced by the method described in 2) or (3), an aqueous flame retardant free from the above-mentioned problems can be obtained. The present invention was completed based on this knowledge.

As is clear from the above description, an object of the present invention is to provide a condensed guanidine phosphate aqueous flame retardant having improved thermal stability and a method for producing the same. Another object is to provide a cellulosic material processed product that is flame retardant treated with the flame retardant.

Other purposes will become clear from the description below.

[Invention composition effect]

The present invention has the following main configurations (1) and (2) or 4.
) has an embodiment configuration.

(1) 1 to 1 for an aqueous solution of condensed guanidine phosphate
An aqueous flame retardant containing 5% by weight of boric acid or 1 to 10% by weight of borax.

(2) The above-mentioned (1), in which a reaction product obtained by melting ammonium phosphate and dicyandiamide in a molar ratio of 1:0.8 to 1.2 in an ammonia atmosphere is used as the condensed guanidine phosphate. The aqueous flame retardant described in .

(3) As condensed guanidine phosphate, ammonium phosphate, dicyandiamide, and urea are used in a molar ratio of 1:065 to 1.
．． The above (1) using a reaction product obtained by melting reaction in an ammonia atmosphere at 5:0.1N1
) The aqueous flame retardant described in item 1.

(4) The aqueous flame retardant according to item (1), wherein the concentration of condensed guanidine phosphate is to-so weight % with respect to the aqueous solution of condensed guanidine phosphate.

The condensed phosphorous guanidine salt, which is the active ingredient of the aqueous flame retardant of the present invention, is preferably produced by the following method.

Using ammonium phosphate, dicyandiamide and urea, and setting their mutual molar ratio to the preferred range described below,
Preferably, the reaction product is obtained by performing a melt reaction in an ammonia atmosphere. Next, when dissolving this reaction product in water to obtain an aqueous solution, the reaction product is heated and dissolved while adding an additive amount of boric acid or borax, and more preferably, the water-insoluble water by-produced during the above-mentioned melting reaction is dissolved. Filter the ingredients. Although the method of filtration is not limited, smooth filtration can be achieved by using diatomaceous earth, activated carbon, or activated clay as a filtration agent.

The molar ratio of raw materials for producing condensed guanidine phosphoric acid salt is 0.5 to 1.5 mol, preferably 0.8 to 1.2 mol, of dicyandiamide per 1 mol of ammonium phosphate. If the latter is less than 0.5 mol.

The generation of by-products is small and the yield is high, but the thermal stability is low and the target level is not reached.On the other hand, when the amount exceeds 1.5 mol, condensed guanidine phosphate with high thermal stability is obtained. However, the production rate of by-products increases and the yield decreases, and when the guanidine is used as an aqueous flame retardant, crystals tend to precipitate at low temperatures, making it inconvenient to handle.

The reaction temperature for producing condensed guanidine phosphate can preferably be selected from any temperature within the range of 140 to 200°C. However, in view of the configuration of the reactor used and the desired reaction time, it is desirable to carry out the reaction at a constant temperature whenever possible; if the reaction temperature is too low in relation to the time required, dicyandiamide If the addition rate to the guanidine group is low and the temperature is too high, on the other hand, the production ratio of water-insoluble by-products will rapidly increase, which is not preferable.

The melt reaction between ammonium phosphate and dicyandiamide according to the present invention is desirably carried out in the presence of urea and in an ammonia gas atmosphere, and gives preferable results. The method of supplying ammonia gas for carrying out the melting reaction in an ammonia gas atmosphere is not limited, but preferably, a considerable amount of ammonia gas is supplied and vented into the reactor to replace the gas generated by the melting reaction. do.

What is the reason for allowing urea to coexist in the melting reaction?

Firstly, even when the ratio of dicyandiamide, which is a reaction raw material, to ammonium phosphate is relatively low, the reduction in thermal stability of the reaction product as a flame retardant for paper can be suppressed, and secondly, the reaction product This is because, as a condensed guanidine phosphate, it is well suited for improving the performance (thermal stability) as a flame retardant when combined with an additive amount of boric acid and/or boric acid. The molar ratio of urea to other raw materials to be coexisting is ammonium phosphate:dicyandiamide:
The ratio of urea is 1:o, 5-1.5: 0.1-1, preferably 1:0.5-1.3: 0.1-1, and the lower limit of the molar ratio of dicyandiamide to ammonium phosphate is urea. 0.8 to 0.5 when not coexisting
Similarly, the upper limit is lowered from 1.2 to ! , can be increased to 5.

The flame retardant of the present invention is prepared by adding and dissolving an additive amount of boric acid and/or borax into an aqueous solution of condensed guanidine phosphate. The addition amount of the boric acid and/or borax can improve the thermal stability of the flame retardant if it is as large as possible. However, on the other hand, phosphorus element is more effective than boron element in terms of flame retardant performance.
It is not preferable to significantly increase the amount of boric acid and/or boron added, and the amount must be determined by comparing and considering the required amount of adhesion to the final paper, flame retardancy, thermal stability, and other requirements.

Incidentally, the solubility of boric acid in water is 4.0 at 20°C.
It is 7100g. However, as shown in the attached figure, the solubility of boric acid (and borax, decahydrate) in a condensed guanidine phosphate solution varies depending on the concentration (wt%) of condensed guanidine phosphate in the solution. The solubility of boric acid also increases as . However, such a tendency is not observed for borax. The amount (g) of boric acid (or borax) dissolved in the figure is based on 100 g of the condensed guanidine phosphate salt aqueous solution.

The concentration of condensed guanidine phosphate, boric acid, or borax, which is an active ingredient of the aqueous flame retardant of the present invention, can be easily adjusted as long as the total concentration of solids in the aqueous solution is 60% by weight or less. Therefore, it is advantageous to prepare the composition in advance at a concentration of 60% by weight, and then dilute it to an appropriate concentration (for example, 30% by weight) as required at the time of use. In addition, when filtering the undissolved components by-produced during the melt reaction for producing condensed guanidine phosphate mentioned above from the condensed guanidine phosphate solution, it is preferable to easily filter the condensed guanidine phosphate at a high concentration. The solution is heated to 60-60°C. If boric acid and/or borax are added during the heating, there is no need to separately dissolve boric acid and/or borax after the above-mentioned filtration, which is advantageous in terms of the process.

The concentration of the guanidine in the condensed guanidine phosphate aqueous solution according to the present invention is not limited, but a concentration of 60% by weight or less and 10% by weight is easy to produce and convenient to use.

The amount of boric acid or borax added to the aqueous solution is preferably 1 to 15% by weight in the case of boric acid and 1 to 10% by weight in the case of borax.
When both of these are used together, the total amount thereof is preferably 1 to 15% by weight. Even if it is added in excess of 15% by weight (boric acid or a combination of boric acid and borax) or 10% by weight (using borax), it should be dissolved in condensed guanidine phosphate and cooled to room temperature, or dissolved at room temperature. During storage, some of the boric acid or borax precipitates as crystals, causing the product to warp and become inconvenient to handle as an aqueous flame retardant. Further, if the amount of boric acid or borax added is less than 1% by weight, the thermal stability effect of the aqueous flame retardant will be significantly reduced, which is not preferable.

The aqueous flame retardant of the present invention includes various cellulosic materials,
For example, it is foamable and non-hygroscopic and can be used as a flame retardant treatment agent for wallpaper, cardboard, carpet, plywood, felt, etc.
Since it has become possible to produce flame-retardant paper that has favorable conditions such as being able to impart rust prevention properties and has greatly improved thermal stability, it has become possible to produce a flame-retardant paper that is embossed and used as a base paper for PVC wallpaper. It is particularly effective when used as

The aqueous flame retardant of the present invention will be described below with reference to Examples and Comparative Examples.

The test method was as follows.

(1) Flame retardancy (char length) Cut paper (Whatman 113) into a size of 20 x 30 cs, immerse it in an aqueous solution of each flame retardant product and reagent for 30 minutes at room temperature, and then use a roll wringer to achieve the specified size. Squeeze while adjusting the coating amount to 50±2℃.
Dry in a constant temperature bath for 48 hours. Place this filter paper in a desiccator.
(Contains silica gel for drying) After keeping it for a day and night, JIS
The carbonization length was measured using the Z-215Or thin material flame retardant test method (45° Metkel burner method). The heating time was 10 seconds, and the maximum value among the three tests was adopted.

(2) Thermal stability Toyo Kishigami No. 5A (diameter 11 cm) was treated in the same manner as in (1) to attach a flame retardant, and then JIS P-8123
Hunter Whiteness Test Method for Paper and Pulp" was measured with a color difference meter. Heating was carried out in an oven at 200±5° C. for 3 minutes and measurements were taken on 5 different pieces of paper.

(3) After treating hygroscopic Toyo Roshi No. 5A (diameter 1) in the same manner as in (1) to attach a flame retardant, cut out a 5 x 5 cm piece of paper and dry it in a constant temperature dryer at 100°C for 1 hour. After 30℃
The sample was placed in a humidifier with a relative humidity of 60%, and the weight increase rate after being left for 24 hours was determined. The untreated paper was used as a blank test and the ratio was shown as compared to this.

(4) Rustability: Place a thumbtack, paperclip, or nail head of a stapler in close contact with similarly treated filter paper, and leave it in a humidifier at 30℃ and 60% relative humidity for 30 days to visually check for rust. I observed it.

Example-1 A mixture of 4 eog (4 moles) of ammonium dihydrogen phosphate and 338 g (4 moles) of dicyandiamide was preheated to 200°C (111f) in oil temperature and ammonia gas was added to an 815 Emperor's tabletop Nigu [Model 5WH manufactured by Irie Seisakusho ■]. The entire amount was added and kneaded while passing through the mixture at a rate of 25 L/min.

After about 10 minutes, the mixture became molten, and gas began to be generated, and the reaction progressed somewhat like an endothermic reaction. 2 at content temperature 160℃±5℃
After the reaction was carried out for a certain period of time, the power to the heater etc. was turned off, the mixture was taken out from the Nigu, and after being solidified at room temperature, it was weighed to obtain 778 g of a reaction product. This was dissolved in water and the undissolved matter was removed by adsorption to a filter layer of diatomaceous earth to obtain a condensed guanidine phosphate aqueous solution (aqueous solution with a concentration of about 40% in terms of solid content). 10 parts by weight, ■
8 parts by weight of boric acid, 4 parts by weight of borax (decahydrate), and 5 parts by weight of borax were added, heated to about 70°C to completely dissolve, and then cooled to room temperature. After adhering to filter paper using these aqueous solutions, tests for flame retardancy, thermal stability, etc. were conducted to obtain surface finish results.

Examples 2 to 3 The same operation as in Example 1 was carried out except that the molar ratio of ammonium dihydrogen phosphate and dicyandiamide was changed, and the amount of boric acid etc. added was also changed as shown in Table 2.

Example-4 The same process as in Example-1 was performed except that diammonium hydrogen phosphate was used.

Example 5 Ammonium dihydrogen phosphate, dicyandiamide, and urea were used as raw materials and reacted at a molar ratio of t:0.75:t. Post-treatment was performed according to Example-1.

Comparative Examples 1 to 3 The aqueous solutions of condensed guanidine phosphate salts obtained in the operations of Examples 1 to 3 were applied to see-through filter paper without addition of boric acid, and tests for flame retardancy and the like were conducted.

As can be seen from the surface test results, the aqueous flame retardant of the present invention has excellent performance in terms of flame retardancy, thermal stability, hygroscopicity, and rust resistance.

In the case of guanidine sulfamate, the flame retardant performance is extremely poor, and no effect can be seen at the same level of adhesion as the flame retardant of the present invention.Also, it has high hygroscopicity, and in the rusting test, it did not cause rust on the nail after 2 days. occurred. Although guanidine phosphate has good flame retardancy, it has extremely poor thermal stability, and when heated to 200° C., its commercial value is lost.

Next, the thermal stability of the condensed guanidine phosphoric acid salts alone, which are the reaction products of ammonium phosphate and dicyandiamide shown in Comparative Examples 1 to 3, varies slightly depending on the selection of the 1 molar ratio, but it cannot be said that the thermal stability is sufficient.

However, by adding the required amount of boric acid or borax, the thermal stability can be significantly improved and reach a practically sufficient level. On the other hand, in the case where boric acid or the like is simply added to guanidine phosphate, although a similar improvement effect is seen in terms of thermal stability, the conventional drawback that the treated paper becomes hard is not eliminated.

In contrast, paper treated with the flame retardant of the present invention.

It is more flexible than guanidine phosphate and stronger than paper treated with guanidine sulfamate.

It has been known that when guanidine sulfamate is used, the treated paper becomes too soft and loses its stiffness, and the present invention has advantages in this respect as well.

Comparative Examples 4 and 5 The raw material molar ratios in Examples 1 and 5 were unchanged, and in order to observe the influence of the ammonia gas atmosphere during the melting reaction, ammonia was not used and 160"0 was used.

The results of the 2-hour reaction and comparison of the products are shown in Table-■
When ammonia was not used, the water-insoluble residual liquid in the product increased and the filtration operation took a long time, resulting in unfavorable results in terms of yield.

Table-II

[Brief explanation of drawings]

The figure is a solubility curve showing the solubility (20°C) of boric acid or boric acid in the condensed guanidine phosphate aqueous solution according to the present invention. In the figure, the vertical axis shows the dissolved amount (g) of boric acid (boric acid), and the horizontal axis shows the condensed guanidine phosphoric acid salt concentration (% by weight). Further, the curve +gin in the figure indicates the solubility of boric acid, and the curve +gin indicates the solubility of boric acid. that's all

Claims (4)

[Claims] (1) 1 to 15 for an aqueous solution of condensed guanidine phosphate
An aqueous flame retardant containing 1 to 10% by weight of boric acid or 1 to 10% by weight of borax. (2) The claim uses a reaction product obtained by melting and reacting ammonium phosphate and dicyandiamide in a molar ratio of 1:0.8 to 1.2 in an ammonia atmosphere as the condensed guanidine phosphate. The aqueous flame retardant according to item (1). (3) As condensed guanidine phosphate, ammonium phosphate, dicyandiamide and urea are used in a molar ratio of 1:0.5 to 1.
．． The aqueous flame retardant according to claim 1, which uses a reaction product obtained by melting reaction in an ammonia atmosphere at a ratio of 5:0.1 to 1. (4) The aqueous flame retardant according to claim (1), wherein the concentration of the condensed guanidine phosphate is 10 to 60% by weight based on the aqueous solution of the condensed guanidine phosphate.