JP3719548B2 - Composite alkali metal salt, method for producing the same, and builder for detergent - Google Patents

Description

【００５３】
実施例５及び比較例５
実施例１で得られた複合アルカリ金属塩及び比較例１のδ−Ｎａ₂Ｓｉ₂Ｏ₅を用いてカチオン交換速さの測定を行った。得られた結果を図５のグラフに示す。図５の結果から、実施例１で得られた複合アルカリ金属塩は、投入後瞬時にしてＣａ固定能力の全力を発揮できることが明らかとなり、徐々に効果を発揮するδ−Ｎａ₂Ｓｉ₂Ｏ₅とは格段の違いがあることが判った。
【００５４】
実施例６
実施例１の炭酸化を途中で中断し、図６に示す粉末法Ｘ線回折パターンのようにδ−Ｎａ₂Ｓｉ₂Ｏ₅の残存する複合アルカリ金属塩を製造した。なお、原料となるδ−Ｎａ₂Ｓｉ₂Ｏ₅の粉末法Ｘ線回折パターンは２θ＝２２゜の最高Ｘ線回折線強度(Ｉ₁)が６５００ｃｐｓであり、図６の炭酸化処理後の最高Ｘ線回折線強度(Ｉ₂)は１３００ｃｐｓであったので、結晶化度(Ｓ)％は２０％であった。得られた複合アルカリ金属塩のＣＥＣと吸湿重量増加率を測定したところ、２１５ｍｇ−ＣａＯ／ｇと１.５重量％であった。また、複合アルカリ金属塩の化学分析によるモル比は、ＳｉＯ₂：Ｎａ₂Ｏ：ＣＯ₂＝１.９７：１.０：０.６５であった。
【００５５】
【発明の効果】
本発明によれば、高いＣａイオン交換能、優れたＣａイオン交換速さ及び優れた耐吸湿性を有し、従って、合成洗剤用ビルダーとして有用な高い硬水軟化能を有し、且つ耐吸湿性に優れた複合アルカリ金属塩及びその工業的に有利に生産できる新規な製造方法を提供することができる。
【図面の簡単な説明】
【図１】実施例１で得られた複合アルカリ金属塩の粉末法Ｘ線回折パターンを示す図である。
【図２】実施例２で得られた複合アルカリ金属塩の粉末法Ｘ線回折パターンを示す図である。
【図３】実施例３で炭酸化処理の原料として使用した結晶性層状珪酸カリ・ソーダの粉末法Ｘ線回折パターンを示す図である。
【図４】実施例３で得られた複合アルカリ金属塩の粉末法Ｘ線回折パターンを示す図である。
【図５】実施例５並びに比較例５のカチオン交換速さを示すグラフである。
【図６】実施例６で得られた複合アルカリ金属塩の粉末法Ｘ線回折パターンを示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite alkali metal salt, a method for producing the same, and a builder for a synthetic detergent. More specifically, the present invention relates to a composite alkali metal salt of a crystalline alkali carbonate and a substantially amorphous alkali silicate, a method for producing the same, and a detergent builder using the alkali metal salt.
[0002]
[Prior art]
Synthetic zeolite (zeolite A) has been used exclusively as a builder for synthetic detergents having water softening action instead of sodium tripolyphosphate.
Recently, as a detergent builder that can replace zeolite A, crystalline layered sodium silicate, mainly sodium disilicate (δ-Na₂Si₂O_Five) Has been developed and put to practical use. The feature of sodium disilicate is that while zeolite A is an insoluble particle, it is a soluble particle that can be dissolved within the washing time and Mg²⁺It is said that the exchange ability is high.
[0003]
Layered sodium silicate (e.g. Na₂Si₂O_Five) Theoretically has a cation exchange capacity higher than that of zeolite A, and is expected to have a high water softening ability in the use of a detergent containing the same. The ion exchange ability cannot be demonstrated. In addition, the fact that the particles are water-soluble is advantageous in that the particles do not adhere to the laundry, but the above-mentioned problems as well as the high hygroscopicity cause the powder detergent to solidify, There is also a drawback that dispersion in washing water becomes worse.
[0004]
In order to solve these drawbacks, a method for modifying Ca and Mg by introducing them into alkali silicate has been proposed (Japanese Patent Laid-Open No. 7-330325). However, although this method improves moisture absorption resistance, it has no effect on the improvement of ion exchange capacity, and Ca in hard water is not affected.²⁺And Mg²⁺There is a contradiction in the concept of introducing these in advance into the builder that removes, and an essential solution has not yet been reached.
[0005]
There is known a method for producing a detergent builder by adding a hydrogen peroxide solution to a product obtained by reacting crystalline layered sodium silicate such as sodium disilicate with at least one acid at a pH of 9 to 13 under stirring. (JP-A-6-183723, JP-A-6-183724). This method uses CO as the acid.₂When gas is used, kanemite (NaHSi₂O_Five・ 3H₂O) and sodium percarbonate (Na₂CO_Three・ 1.5H₂O₂), But kanemite crystals have a small ion exchange capacity and cannot be expected to have a water softening capacity higher than that of zeolite A.
[0006]
JP-A-4-275400 discloses a granular carrier such as sodium carbonate with SiO.₂/ M₂It discloses that a composite alkali metal salt that adsorbs and / or absorbs an alkali silicate aqueous solution having an O molar ratio of 1.6 to 3.5 is used as a builder for detergents.
[0007]
[Problems to be solved by the invention]
Recently, synthetic detergents are rapidly becoming compact. The reason for this is the development of a powerful degrading enzyme for fat and protein components adhering to contaminated clothing, and the results of technological development related to activator builders and their formulation. Is big.
[0008]
It is essential that the smaller the amount used and the higher the detergency is, the more compact the progress is, and therefore it is inevitable that each component has high performance and high functionality.
The builder is also required to have a high water softening ability, but sodium disilicate which has been newly used does not necessarily significantly exceed zeolite A.
Unlike the present invention, the composite alkali metal salt according to Japanese Patent Application Laid-Open No. 4-275400 has a point that should be improved in terms of physical properties and functions.
[0009]
In view of the above-mentioned problems, the present inventors have conducted research for many years on a builder that can follow the demand for a compact detergent.
[0010]
That is, an object of the present invention is to provide a composite alkali metal salt useful as a builder for a synthetic detergent having high water softening ability and excellent moisture absorption resistance, and a novel production method capable of industrially producing it. There is to do.
[0011]
[Means for Solving the Problems]
  The composite alkali metal salt to be provided by the present invention is:MHCO ₃ (M represents Na, K or Li)Particles and, SiO ₂ : M ₂ Carbonation of a crystalline layered alkali silicate having an O molar ratio of 1.7 to 2.5: 1 yields a layered crystal structure.
Crystallinity (S:%) = (I ₂ / I ₁ ) × 100
(However, I ₁ Is the highest X-ray diffraction intensity of crystalline layered alkali silicate, I ₂ Is the highest X-ray diffraction intensity after carbonation of the crystalline layered alkali silicate) and the crystallinity of the alkali metal silicate amorphousized to 50% or lessA composite assembly comprising particles, the composite assembly being SiO₂: M₂ O:CO₂It is characterized by having a molar ratio of 1.7 to 2.5: 1: 0.25 to 2.0 and a moisture absorption of 5% by weight or less.
[0012]
  The present invention also provides a method for producing a composite alkali metal salt, wherein carbon dioxide is introduced into crystalline layered alkali silicate in the presence of moisture to precipitate alkali carbonate crystal particles andcrystalThe disordered layered structure
Crystallinity (S:%) = (I ₂ / I ₁ ) × 100
(However, I ₁ Is the highest X-ray diffraction intensity of crystalline layered alkali silicate, I ₂ Is the highest X-ray diffraction intensity after carbonation of the crystalline layered alkali silicate).A structural feature is that the carbonation reaction is carried out until amorphous particles are obtained.
[0013]
Furthermore, a builder for a synthetic detergent to be provided by the present invention is characterized in that the composite alkali metal salt is used as an active ingredient.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The composite alkali metal salt according to the present invention is a powder of a composite salt of alkali carbonate and alkali silicate as described above. According to the powder method X-ray diffraction analysis of this powder, alkali carbonate is a crystalline particle, and in many cases, it is confirmed as a crystalline particle of alkali hydrogen carbonate.
[0015]
  Meanwhile, alkali silicateIs non-Crystalline particles. hereNonCrystalline particles
Crystallinity (S:%) = (I₂/ I₁) × 100
(However, I₁Is the highest X-ray diffraction intensity of crystalline layered alkali silicate, I₂Means the highest X-ray diffraction intensity after carbonation of the crystalline layered alkali silicate), and means an amorphous property having a crystallinity of 50% or less, preferably 30% or less.
[0016]
Next, the composite alkali metal salt according to the present invention is not based on a simple mixture of an alkali carbonate and an amorphous alkali silicate obtained from water glass as conventionally known. One major characteristic is that it has been converted into an aggregate.
[0017]
Therefore, because of this feature, particles having excellent cation exchange ability and moisture-resistant physical properties can be formed as described later.
[0018]
  Such composite aggregate SiO₂: M₂O (M is as defined above): CO₂Is often in the range of (1.7-2.5): 1: (0.25-2.0), preferably (1.8-2.2): 1: It is in the range of (0.5 to 2.0). SiO, which is a quantitative indicator of alkali carbonate and alkali silicate₂/ CO₂Is often in the range of 1.0 to 10, preferably in the range of 1.0 to 3.0. The reason is greater than 10And nonThis is because the crystalline alkali silicate cannot be formed, and therefore the cation exchange ability and moisture absorption resistance are insufficient, and the advantage as a composite alkali metal salt cannot be obtained. This is because it is industrially difficult and is saturated with physical improvement.
[0019]
The composite alkali metal salt according to the present invention has the structural features as described above. Therefore, the cation exchange capacity (CEC) defined below is at least 200 mg-CaO / g, preferably 230 mg-CaO / g, and a moisture absorption rate as defined later, is not more than 5% by weight, preferably not more than 3% by weight, and has a remarkable function.
[0020]
Zeolite A or an alternative crystalline sodium disilicate (Na₂Si₂O_Five) Has a CEC of about 150 mg-CaO / g, and the above-mentioned remarkable functions of the composite alkali metal salt according to the present invention are suitable as a builder for a synthetic detergent as compared with the hygroscopic resistance of sodium disilicate. Would be treated as When this composite alkali metal salt is used as a builder for a synthetic detergent, it goes without saying that if necessary, zeolite A, sodium disilicate (δ-Na₂Si₂O_Five), Sodium tripolyphosphate, sodium pyrophosphate, sodium polyacrylate, various amino acid sodiums, sodium phosphonates, sodium carbonate, sodium percarbonate, sodium perborate, etc. Can be used in combination with other builder components.
[0021]
  As described above, the method for producing a composite alkali metal salt according to the present invention introduces carbon dioxide into the crystalline layered alkali silicate in the presence of water to precipitate alkali carbonate crystal particles, and the crystalline layered structure of alkali silicate. Irregularly
Crystallinity (S:%) = (I ₂ / I ₁ ) × 100
(However, I ₁ Is the highest X-ray diffraction intensity of crystalline layered alkali silicate, I ₂ Is the highest X-ray diffraction intensity after carbonation of the crystalline layered alkali silicate).The carbonation reaction is carried out until amorphous particles are obtained.
[0022]
The crystalline layered alkali silicate used as a starting material is not particularly limited as long as it has a high cation exchange capacity, but in many cases it is SiO 2.₂/ M₂The molar ratio of O (M is as defined above) is in the range of 1.7 to 2.5, especially sodium disilicate (δ-Na₂SiO₂O_Five) And potassium disilicate (K₂Si₂O_Five) Is preferred.
[0023]
Such crystalline alkali silicate may be modified by substituting a part of the crystal lattice with a component such as boron or aluminum as necessary. In order to adjust the basicity, other amorphous alkali silicates derived from caustic alkali or water glass, and other crystalline alkali silicates such as alkali metal silicates and orthosilicate alkalis are optionally added as necessary. Can be used as However, such auxiliary raw materials can be handled in the production process of the layered alkali silicate as the main raw material, and it is preferable.
[0024]
A method for producing the crystalline layered alkali silicate powder is known, and the main raw material in the present invention can also be easily obtained by this known method. For example, the following method is adopted:
That is, SiO₂/ M₂O molar ratio is 2.1-4.2, preferably 2.3-3.7, SiO 2₂An alkali silicate aqueous solution having a content of 23 to 38% by weight, or the above molar ratio, SiO 2₂A powdery alkali silicate having a content of 45 to 63% by weight and an auxiliary material such as an alkali agent or a modifier as described above are mixed as necessary, and the mixture is dried in the range of 100 to 350 ° C.
Next, the dried product is crystallized by baking at a temperature of 650 to 800 ° C. for Na salt, 500 to 650 ° C. for K salt, and 450 to 750 ° C. for mixed salt. The firing time is preferably in the range of 0.1 to 3 hours.
The crystal powder obtained is an alkali silicate having a layered structure and is a preferred starting material in the present invention.
[0025]
Carbonic acid gas is introduced into the crystalline layered alkali silicate according to the present invention in the presence of moisture to cause a carbonation reaction. Such carbonation is preferably performed with carbon dioxide gas containing 5 to 50 kPa of water vapor. The reason for this is that if the water vapor pressure becomes higher than the above range, for example, when alkali disilicate is carbonated, the reaction of the following formula (1) proceeds, the alkali silicate dissolves in the generated alkaline solution, and the original water There is a possibility of returning to glass, which is not preferable.
[0026]
[Chemical 1]
M₂Si₂O_Five+ NH₂O = MHSi₂O_Five+ MOH · (n-1) H₂O ... (1)
[0027]
On the other hand, if the water vapor pressure in carbonation is too low, the reaction does not proceed and takes too much time, which is not industrially preferable.
[0028]
As an embodiment for carrying out such a carbonation reaction, for example, a method in which carbon dioxide gas is passed through desired warmed water is preferable because uniform carbonation proceeds.
[0029]
Carbonation in the present invention needs to be performed until the crystalline alkali silicate having a layered structure is substantially amorphized. In many cases, the carbonation of a stable composition can be carried out by continuing the carbonation until the water-containing carbon dioxide gas is substantially saturated with absorption.
[0030]
Thus, the crystalline alkali silicate becomes irregular with a regular layered structure and becomes substantially amorphous, and crystal grains of alkali carbonate, preferably MHCO._ThreeOf alkali hydrogen carbonate crystals are formed and converted to a composite alkali metal salt. Such a complex alkali metal salt has the above-described physicochemical characteristics and is optimal as a builder for a synthetic detergent.
[0031]
The composite alkali metal salt according to the present invention is based on the following theoretical basis.₂Si₂O_FiveSuch an alkali silicate having a layered crystal structure is obtained by carbonation in the presence of water. That is, sodium disilicate Na, which has higher water softening ability than zeolite A₂Si₂O_Five(Molecular weight 182) two Na ions exchange with one Ca. Thus, the theoretical exchange capacity is about 300 mg / g for CaO (molecular weight 56), but in practice only shows about half of this value due to solubility. Na₂Si₂O_FiveIs carbonated in the presence of moisture, the reaction product (product molecular weight 244) obtained according to the following formula (2) can capture two Ca, and its theoretical fixed amount is 460 mg / g and Na₂Si₂O_Five1.5 times higher than
[Chemical 2]
Na₂Si₂O_Five+ H₂O + CO₂= NaHSi₂O_Five+ NaHCO_Three  ・ ・ (2)
[0032]
Similarly, K₂Si₂O_FiveHas a theoretical exchange capacity of 260 mg-CaO / g and its carbonated product (KHSi).₂O_Five+ KHCO_Three) Is 410 mg-CaO / g, has a cation scavenging ability 1.6 times that of the former, and has a high water softening ability.
[0033]
One of its features is Na₂Si₂O_FiveAnd K₂Si₂O_FiveThe water-solubility, which is a drawback of the above, is suppressed by neutralization of alkali by carbonation, so that the hygroscopic property is almost lost and the powder solidification property is improved. The second feature is that the layered structure of the original is irregular.
This can be confirmed by a powder method X-ray diffraction pattern. The composite crystal of the present invention has NaHCO 3_ThreeAnd KHCO_ThreeHowever, the original diffraction pattern and NaHSi₂O_FiveAnd KHSi₂O_FiveThere is no or no diffraction pattern, but the crystallinity is low. It is considered that the growth of carbonate crystals between layers breaks the silicic acid structure, and it is assumed that such an irregular silicic acid structure is useful for activating the ion exchange capacity.
[0034]
The third feature is that the water softening speed is extremely high. This is not due to the reaction rate of carbonate radicals and hard water components. This is because, in the case of carbonic acid radicals, it should show a two-stage phenomenon in which half of the water softening ability is initially manifested and then the silicate effect appears. However, in many cases, the composite alkali metal salt of the present invention instantly develops the entire water softening ability. From this, it is presumed that the irregularity of the above-mentioned layered structure of the active substance means a new structure that is advantageous for ion exchange, for example, a structure having an increased interlayer distance.
[0035]
Further, since the free alkali component also has a moderate basicity that is neutralized, it is possible to more preferably exert the function of the surfactant, and therefore, it is suitable as a builder for a synthetic detergent. It can be recommended as a builder who can follow the downsizing.
[0036]
【Example】
Hereinafter, the present invention will be described in detail by way of examples and comparative examples, but the present invention is not limited to the following examples. In addition, the measured value in a present Example was measured by the method shown next.
[0037]
(1-a) Cation exchange capacity (CEC)
Weigh accurately 0.1 g of sample, NH_FourCalcium chloride aqueous solution with 2 ml of Cl buffer solution (concentration is CaCO_Three500 ppm, pH is about 10.5) and added to 100 ml, stirred at 25 ° C. for 10 minutes, filtered using a membrane filter (Advantic, manufactured by Nitrocellulose) having a pore size of 0.2 μm, The amount of Ca contained in 10 ml of the filtrate was measured by EDTA titration. From the value, the calcium ion exchange capacity (mg-CaO / g) of the sample was determined. NH_FourCl buffer solution is reagent grade NH_Four70 g of Cl and 570 ml of reagent-grade ammonia water were dissolved in pure water and prepared to a constant volume of 1 liter.
[0038]
(1-b) Cation exchange rate
0.25 g of sample is precisely weighed and the same NH as above_FourCalcium chloride aqueous solution with 2 ml of Cl buffer solution (concentration is CaCO_ThreeAs 500 ppm) in 500 ml and at 25 ° C.²⁺Using an ion electrode, Ca over time²⁺Changes in ion concentration were measured. The change with time of the calcium ion exchange amount (mg-CaO / g) of the sample was calculated from the value. The measuring device used was a Horiba PH / ION METER F23 type.
[0039]
(2) Hygroscopicity
1.0 g of the sample is precisely weighed in a 100 ml beaker and stored in a constant temperature and humidity room at 30 ° C. and a relative humidity of 80%. The amount of weight increase after storage for 5 hours was precisely weighed to determine the weight increase rate (%) of the stored powder.
[0040]
Example 1
No. 3 sodium silicate [Nippon Chemical Industry Co., Ltd .: SiO₂= 29.0%, Na₂O = 9.5%, SiO₂/ Na₂10 mol of O molar ratio = 3.15] was charged into a container, and 740 g of flake caustic soda [manufactured by Asahi Glass Co., Ltd .: NaOH = 99.5%] was charged with stirring, and heated to 80 ° C. to dissolve. This sodium silicate was put into a Teflon vat, dried with a dryer having a hot air temperature of 300 ° C., and pulverized to 1 mm or less to obtain powdered sodium silicate. Next, the obtained powdered sodium silicate was put in a nickel container, and baked at a temperature of 750 ° C. for 3 hours using an electric furnace for crystallization. The obtained crystalline layered sodium silicate was then pulverized to 1 mm or less. SiO of this crystalline layered sodium silicate₂/ Na₂The O molar ratio is 1.97, and the powder method X-ray diffraction pattern of this crystalline layered sodium silicate was measured.₂Si₂O_FiveThe diffraction pattern was confirmed.
[0041]
100 g of this crystalline layered sodium silicate was charged into a container equipped with a stirrer, stirred, and passed through 40 ° C. warm water.₂The gas was introduced into the container at 100 ml / min. The water vapor partial pressure at this time was 7 kPa. The weight of sodium silicate increased to 135 g, and there was no change in weight even when gas was further introduced. The powder method X-ray diffraction pattern of the obtained composite alkali metal salt is mainly NaHCO 3 as shown in FIG._ThreeDiffraction pattern of δ-Na₂Si₂O_FiveIt was confirmed that the layered crystal structure of sodium silicate was broken only by showing traces. Further, CEC and moisture absorption weight increase rate were excellent values as shown in Table 1. The molar ratio of the composite alkali metal salt by chemical analysis is SiO₂: Na₂O: CO₂Was 1.97: 1.0: 1.25.
[0042]
Comparative Example 1
Crystalline layered sodium silicate (δ-Na) which is an intermediate product of Example 1₂Si₂O_Five) Was used to measure CEC and hygroscopic weight gain, and the results obtained are shown in Table 1.
[0043]
Example 2
Potassium silicate [Nippon Chemical Industry Co., Ltd .: SiO₂= 28.96%, K₂O = 21.75%, SiO₂/ K₂10 mol of O molar ratio = 2.09] was charged into a container, and 112 g of flake caustic potash (manufactured by Asahi Glass Co., Ltd .: KOH = 99.5%) was added under stirring, and dissolved by heating to 80 ° C. This potassium silicate was dried with a spray dryer at an outlet hot air temperature of 110 ° C. to obtain powdered potassium silicate. Next, the powdered potassium silicate was taken in a nickel container, and baked for 1 hour at a temperature of 650 ° C. using an electric furnace to perform crystallization. The obtained crystalline layered potassium silicate was then pulverized to 1 mm or less. This crystalline layered potassium silicate SiO₂/ K₂The molar ratio of O was 2.0, and the powder method X-ray diffraction pattern of this crystalline layered potassium silicate was measured.₂Si₂O_FiveThe diffraction pattern was confirmed.
[0044]
This crystalline layered potassium silicate 100 g was charged into a vessel equipped with a stirrer, stirred, and passed through 50 ° C. warm water.₂The gas was introduced into the container at 100 ml / min. In addition, the water vapor partial pressure at this time was 12 kPa. The weight of potassium silicate increased to 148 g, and there was no change in weight even if gas was further introduced. The powder method X-ray diffraction pattern of the obtained composite alkali metal salt is mainly KHCO as shown in FIG._ThreeDiffraction pattern of₂Si₂O_FiveThis diffraction pattern showed only traces. Further, CEC and the hygroscopic weight increase rate were excellent values as shown in Table 1. The molar ratio of this composite alkali metal salt by chemical analysis is SiO 2₂: K₂O: CO₂Was 2.0: 1.0: 1.5.
[0045]
Comparative Example 2
Crystalline layered potassium silicate (K) which is an intermediate product of Example 2₂Si₂O_Five) Was used to measure CEC and hygroscopic weight gain, and the results obtained are shown in Table 1.
[0046]
Example 3
No. 1 sodium silicate [Nippon Chemical Industry Co., Ltd .: SiO₂= 32.0%, Na₂O = 15.5%, SiO₂/ Na₂O molar ratio = 2.13] 4.53 kg and 15.0 kg of potassium silicate used in Example 2 were charged into a container, and 63 g of flake caustic soda and 168 g of flake caustic potash were charged with stirring, and heated to 80 ° C. to dissolve. . This potassium silicate soda was dried with a spray dryer at an outlet hot air temperature of 110 ° C. to obtain powdered potassium silicate soda. Further, the powdered potassium silicate and soda are dried for 30 minutes with a 300 ° C. blower dryer, and then the powdered potassium silicate and soda are put into a nickel container and are heated at a temperature of 550 ° C. for 1 hour using an electric furnace. Firing and crystallization were performed. The resulting crystalline layered potassium silicate soda was then ground to 1 mm or less. SiO of this crystalline layered potassium silicate soda₂/ (Na₂O + K₂O) molar ratio is 2.0, and the molar ratio of potassium and soda is Na₂O / K₂The O was 0.33. The powder X-ray diffraction pattern shows a clear K as shown in FIG.₂Si₂O_FiveDiffraction pattern and slight δ-Na₂Si₂O_FiveDiffraction pattern.
[0047]
100 g of this crystalline layered potassium silicate / soda was charged into a vessel equipped with a stirrer, stirred, and passed through 50 ° C. warm water.₂The gas was introduced into the container at 100 ml / min. In addition, the water vapor partial pressure at this time was 12 kPa. The weight of potassium silicate and soda increased to 175 g, and there was no change in weight even when gas was further introduced. The powder method X-ray diffraction pattern of the obtained composite alkali metal salt is mainly KHCO as shown in FIG._ThreeAnd NaHCO_ThreeDiffraction pattern of₂Si₂O_FiveIt was confirmed that the layered crystal structure of potassium silicate and soda was broken only by showing traces. Further, CEC and the hygroscopic weight increase rate were excellent values as shown in Table 1. The molar ratio of this composite alkali metal salt by chemical analysis is SiO 2₂: M₂O: CO₂= 2.0: 1.0: 1.5.
[0048]
Comparative Example 3
Using the crystalline layered potassium silicate soda which is the intermediate product of Example 3, CEC and moisture absorption weight increase rate were measured, and the obtained results are shown in Table 1.
[0049]
Example 4
The same No. 1 sodium silicate 18.1 kg as in Example 3 and 5.0 kg of potassium silicate as in Example 2 were charged into a container, and 188 g of flake caustic soda and 56 g of flake caustic potash were added under stirring and dissolved by heating to 80 ° C. . This potassium silicate soda was placed in a Teflon vat, dried with a dryer having a hot air temperature of 300 ° C., and pulverized to 1 mm or less to obtain powdered potassium silicate soda. Next, the powdered potassium silicate soda was placed in a nickel container and baked for 1 hour at a temperature of 670 ° C. using an electric furnace to perform crystallization. The resulting crystalline layered potassium silicate soda was then ground to 1 mm or less. SiO of this crystalline layered potassium silicate soda₂/ (Na₂O + K₂O) molar ratio is 2.0, and the molar ratio of potassium and soda is Na₂O / K₂It was 3.0 with O. When the powder method X-ray diffraction pattern of this crystalline layered potassium silicate and soda was measured, δ-Na₂Si₂O_FiveAnd K₂Si₂O_FiveIt was confirmed that a diffraction pattern of
[0050]
100 g of this crystalline layered potassium silicate / soda was charged into a vessel equipped with a stirrer, stirred, and passed through 50 ° C. warm water.₂The gas was introduced into the container at 100 ml / min. In addition, the water vapor partial pressure at this time was 12 kPa. Potassium silicate and soda increase in weight up to 171g and no more CO₂There was no change in weight even when the introduction of gas was continued. The powder method X-ray diffraction pattern of the obtained composite alkali metal salt is mainly KHCO._ThreeAnd NaHCO_ThreeThe diffraction pattern of Na₂Si₂O_FiveThis diffraction pattern showed only traces, and it was confirmed that the layered crystal structure was broken. Further, CEC and moisture absorption weight increase rate were excellent values as shown in Table 1. The molar ratio of this composite alkali metal salt by chemical analysis is SiO 2₂: M₂O: CO₂= 2.0: 1.0: 1.5.
[0051]
Comparative Example 4
Using the crystalline layered potassium silicate soda that is an intermediate product of Example 4, CEC and moisture absorption weight increase rate were measured and listed in Table 1.
[0052]
[Table 1]

[0053]
Example 5 and Comparative Example 5
The composite alkali metal salt obtained in Example 1 and δ-Na of Comparative Example 1₂Si₂O_FiveWas used to measure the cation exchange rate. The obtained results are shown in the graph of FIG. From the results shown in FIG. 5, it is clear that the composite alkali metal salt obtained in Example 1 can exhibit the full capacity of the Ca fixing ability instantaneously after the addition, and δ-Na that gradually exhibits the effect.₂Si₂O_FiveIt was found that there was a great difference.
[0054]
Example 6
Carbonation of Example 1 was interrupted and δ-Na as in the powder X-ray diffraction pattern shown in FIG.₂Si₂O_FiveThe remaining composite alkali metal salt was prepared. In addition, δ-Na used as a raw material₂Si₂O_FiveThe X-ray diffraction pattern of the powder method shows the maximum X-ray diffraction line intensity (I₁) Is 6500 cps, and the maximum X-ray diffraction line intensity (I₂) Was 1300 cps, the crystallinity (S)% was 20%. When the CEC and moisture absorption weight increase rate of the obtained composite alkali metal salt were measured, they were 215 mg-CaO / g and 1.5% by weight. The molar ratio of the composite alkali metal salt by chemical analysis is SiO₂: Na₂O: CO₂= 1.97: 1.0: 0.65.
[0055]
【The invention's effect】
According to the present invention, it has a high Ca ion exchange capacity, an excellent Ca ion exchange speed and an excellent moisture absorption resistance, and thus has a high water softening ability useful as a builder for synthetic detergents, and also has a moisture absorption resistance. It is possible to provide a composite alkali metal salt excellent in the above and a novel production method that can be advantageously produced industrially.
[Brief description of the drawings]
1 is a view showing a powder X-ray diffraction pattern of a composite alkali metal salt obtained in Example 1. FIG.
2 is a graph showing a powder X-ray diffraction pattern of a composite alkali metal salt obtained in Example 2. FIG.
3 is a graph showing a powder X-ray diffraction pattern of crystalline layered potassium silicate / soda used as a carbonation raw material in Example 3. FIG.
4 is a graph showing a powder X-ray diffraction pattern of a composite alkali metal salt obtained in Example 3. FIG.
5 is a graph showing the rate of cation exchange in Example 5 and Comparative Example 5. FIG.
6 is a graph showing a powder X-ray diffraction pattern of the composite alkali metal salt obtained in Example 6. FIG.

Claims (7)

Crystalline alkali metal carbonate salt particles represented by MHCO ₃ (M represents Na, K or Li) and crystallinity having a SiO ₂ : M ₂ O molar ratio = 1.7 to 2.5: 1 Carbonate layered alkali silicate to form layered crystal structure
Crystallinity (S:%) = (I ₂ / I ₁ ) × 100
(Where I ₁ is the highest X-ray diffraction intensity of the crystalline layered alkali silicate , and I ₂ is the highest X-ray diffraction intensity after carbonation of the crystalline layered alkali silicate). A composite aggregate composed of amorphous alkali metal silicate particles, wherein the composite aggregate is SiO ₂ : M ₂ O: CO ₂ molar ratio = 1.7 to 2.5: 1: 0.25. A composite alkali metal salt having .about.2.0 and a moisture absorption of 5% by weight or less. Carbon dioxide gas is introduced into crystalline layered alkali silicate in the presence of water to precipitate alkali carbonate crystal particles and make the crystalline layered structure of alkali silicate irregular.
Crystallinity (S:%) = (I ₂ / I ₁ ) × 100
Where I ₁ is the highest X-ray diffraction intensity of the crystalline layered alkali silicate , and I ₂ is the highest X-ray diffraction intensity after carbonation of the crystalline layered alkali silicate. A method for producing a composite alkali metal salt, characterized by performing a carbonation reaction until amorphous particles are obtained. The crystalline layered alkali silicate is M ₂ Si ₂ O ₅ (M is Na, K) having a SiO ₂ : M ₂ O (M represents Na, K or Li) molar ratio = 1.7 to 2.5: 1. Or Li represents)). The method for producing a composite alkali metal salt according to claim 2 .   4. The composite alkali metal according to claim 2, wherein the carbonation of the crystalline layered alkali silicate in the presence of water is carried out by introducing carbon dioxide gas containing water vapor of 5 to 50 kPa into the alkali silicate at room temperature. Method for producing salt. Claim 1 Symbol placement detergent builder a composite alkali metal salt of the active ingredient. The builder for synthetic detergents according to claim 5, wherein the complex alkali metal salt has a cation exchange capacity (CEC) of at least 200 mg-CaO / g. The builder for synthetic detergent according to claim 5 or 6 , wherein at least one selected from the group consisting of zeolite A, sodium disilicate, sodium tripolyphosphate, sodium pyrophosphate, sodium polyacrylate, sodium amino acid and sodium phosphonate. A builder for a synthetic detergent characterized by containing a builder component.

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