JPH01190800A - Production of soap - Google Patents

Abstract

PURPOSE:To continuously produce a soap for which any drying step is not necessary, by continuously feeding a fatty acid and a high-concn. aq. alkali soln. as raw materials into a twin-screw kneader having a particular structure and conducting neutralization reaction. CONSTITUTION:A fatty acid and a high-concn. aq. alkali soln. as raw materials are continuously fed through a supply port 1b into a twin-screw kneader A comprising two parallel axes of rotation 3a and 3b and a vast plurality of paddles 4, 4,... each having an axial cross section similar to that of a convex lens and fixed to the axis of rotation 3a or 3b, each pair of paddles, with one fixed to axis 3a and the other fixed to 3b, making a phase difference of 90 deg.. The fed raw materials are continuously carried by means of the compressive force ascribed to screws 5, 5 to a kneading zone Z wherein the paddles 4, 4,... are disposed. In the kneading zone, mechanical shear force applies to the materials while the same is transferred under agitation, so that homogeneous mixing and accordingly neutralization reaction are accomplished. From an outlet port 1a, a soap having a low moisture content which is in the form of a pellet, etc., is discharged. The moisture content of the soap is such that a drying step after the neutralization reaction is not necessary for the obtd. soap, and the neutralization is desirably uniform. Accordingly, the soap has such a high quality as to be suited for use as a toilet soap, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing soap, in particular, a method for producing soap, in particular, by uniformly stirring and mixing raw fatty acids and a highly concentrated alkaline aqueous solution to complete a neutralization reaction. This invention relates to a continuous soap manufacturing method that does not require a drying process.

[Conventional technology]

Conventionally, there are three main methods for producing soap. One is the neutral oil firing method, which involves saponifying fats and oils with an aqueous caustic solution, removing glycerin by salting out to make neat soap with a water content of about 30% by weight, and then drying it by band drying or vacuum drying. , which is extruded into pellets using a pro-ladder.

The other method is fatty acid neutralization method, i.e. fatty acid and concentration of about 30%.
% by weight of a caustic alkali aqueous solution is continuously supplied to cause a neutralization reaction to produce a neat soap having a water content of about 30% by weight, and then the same steps as above are followed. Yet another method is the ester method, in which fatty acids are converted into methyl esters, then an aqueous alkaline solution is added to remove methanol.

Among these methods, the fatty acid neutralization method does not require a salting-out step and can be carried out continuously, so it has been gradually used as a method that greatly improves workability.

[Problem to be solved by the invention]

However, in the fatty acid neutralization method, stirring and mixing can be performed uniformly with neat soap with a water content of about 30% by weight, but when the water content is reduced to 16% by weight or less, which eliminates the need for a drying process, the neutralization reaction products are highly concentrated. Because of its viscosity, it cannot be stirred and mixed uniformly, making it unsuitable for applications that require high quality and uniformity, such as cosmetic soaps.

Therefore, for example, in JP-A-59-20399 and JP-A-61-143500, by devising a neutralization reaction device for fatty acids and aqueous alkaline solutions,
Methods have been proposed for continuously producing soaps with a low water content that do not require a drying step after the neutralization reaction or can significantly shorten the time required for the drying step.

By using a specific neutralization reaction device that is different from the known ones disclosed in these proposed methods, the present invention aims to further homogenize the neutralization reaction and eliminates the need for a drying step after the neutralization reaction. The purpose of the present invention is to provide a method for continuously producing high-quality soap, which has a low water content and is neutralized very uniformly, and can be sufficiently applied to cosmetic soaps. It is said that

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors used a twin-screw kneader having a kneading zone in which a number of paddles of a specific shape form a specific arrangement as a neutralization reaction device. By continuously supplying raw fatty acids and a highly concentrated alkaline aqueous solution into this kneader to carry out a neutralization reaction, a product with a low moisture content that does not require a drying process after the neutralization reaction is produced. The inventors have discovered that it is possible to continuously produce high-quality, uniformly neutralized soap, and have arrived at the present invention.

That is, in the present invention, fatty acids as raw materials and high concentration This invention relates to a soap manufacturing method characterized in that a soap that does not require a drying step is continuously manufactured by continuously supplying an alkaline aqueous solution to perform a neutralization reaction.

[Structure and operation of the invention]

The twin-screw kneader used as a reaction device in the present invention is:
As described above, a large number of paddles fixed to each axis have a convex lens shape in their axial cross section, and form pairs with a phase difference of 90 degrees between the two axes. 1 to 3 show an example A of such a two-screw kneader.

In these figures, an oblong cylindrical trough 1 has a discharge port 1a at one end, a fatty acid supply port 1b at the top of the other end, and a highly concentrated alkaline aqueous solution supply port 1b at the bottom of the other end. Two rotating shafts 3a are synchronously rotated in the same direction by the drive device 2.

3b are arranged in parallel along the horizontal direction, and both rotating shafts 3a,
'3b has a large number of paddles 4 each having a convex lens-shaped axial cross section.
4... and a screw 5 located on the raw material supply port 1b, 1b'' side, that is, on the proximal end side, are fixedly installed.

The paddles 4 of one rotating shaft 3a are arranged in order from the tip side with the arrangement angle of the object located at the tip of the shaft as a reference (0 degree).
0 degrees 2 pieces, 45 degrees 3 pieces, 90 degrees 4 pieces, 180 degrees (0 degrees)
A plurality of sheets, such as three sheets and four sheets at 135 degrees, are densely arranged so that each sheet has a different phase. Further, the paddles 4 of the other rotating shaft 3b are arranged in order from the distal end side, with the arrangement angle of the one located at the most distal end of the rotating shaft 3a as a reference (0 degrees): two 90 degree paddles, three 135 degree paddles, four 0 degree paddles. Adjacent paddles 4.4 are closely arranged in pairs with a phase difference of 90 degrees, such as three paddles 4.4 at 90 degrees, and four paddles 4.4 at 45 degrees. In addition, between the inner wall of the trough 1 and each paddle 4, and between each pair of paddles 4.4, both rotating shafts 3a,
3b is set so as to maintain a slight clearance in the synchronous rotation operation.

In the kneading machine configured as described above, both rotating shafts 3a and 3b are synchronously rotated in the same direction via a motor built in the drive device 2 or via a heddle or chain with the motor, and the raw material supply port 1
b, lb', by continuously feeding raw fatty acids and a highly concentrated alkaline aqueous solution into the trough 1 after heating them as necessary, the supplied raw materials meet the pressing force of the screws 5, 5. The mixture is sequentially sent to the kneading zone Z where paddles 4, 4, etc. are arranged, and in the process of being kneaded and moving within this mixing zone Z, it is subjected to mechanical shearing force and mixed uniformly, and a neutralization reaction occurs. Completed and finally the outlet 1a
It is excreted as soap with a low moisture content in the form of pellets.

Here, the cross section of the kneading zone Z includes both rotating shafts 3a.

Since the pair of paddles 4.4 between the paddles 3b rotate synchronously with a 90 degree phase difference, the paddles 4.4 in FIG.
There are always three zones 2. as shown by d+. ．． It is divided into 22°Z3. Taking the shaded zone Z as an example, the cross-sectional area of each zone Z1 to Z3 is 4.4 mm for both paddles.
As the image rotates, it enlarges in the process from Fig. 4 (a) to Fig. 4 (bl), then shrinks in the process of Fig. 4 (c) and Fig. 4 (d+), and then again Fig. 4 fa ) Furthermore, Fig. 4(b)
), it repeats expansion and contraction. Therefore, the soap raw materials moving through the kneading zone Z are forcibly subjected to repeated volume changes of compression and stretching during this movement process, thereby becoming extremely uniformly mixed and completely neutralized.

Note that the number of paddles installed on each of the rotating shafts 3a and 3b, the phase difference between paddles 4 adjacent in the axial direction, the number of paddles in each phase group, etc. can be set in various ways, and by devising a combination of these, crosstalk can be reduced. The effect can be adjusted.

In addition, as the paddle 4, in addition to a normal flat paddle 4a with both sides in the same phase as shown in Fig. 5 (al), a helical paddle 4b with both sides out of phase as shown in Fig. 5 (bl) can be used. Yes, helical paddle 4b
The paddles exert a kneading action as well as a feeding action or a returning action depending on their direction, so by arranging them in combination with the flat paddles 4a at important points in the kneading zone Z, the soap raw materials can be locally fed forward or backward within the kneading zone Z. This further improves the kneading effect.

In addition, the number of arranged helical paddles 4b, the number of flat paddles 4
The installation ratio with a can be set in various ways.

In addition, various combinations of paddle pairs between the two rotating shafts 3a, 3b are possible, such as helical paddles 4b, 4b facing the same direction, helical paddles 4b, 4b facing opposite directions, flat paddles 4a, 4a pairing each other.

The fatty acids used as raw materials in the present invention include fatty acids similar to those used in ordinary soaps, such as beef tallow fatty acids, coconut oil fatty acids, and simple fatty acids obtained from these fatty acids, which are conventionally known as bases for soaps. Various animal and vegetable fatty acids can be used alone or in combination of two or more. Further, as the alkali, lower amines such as sodium hydroxide, potassium hydroxide, and triethanolamine can be used. These alkalis are
As a highly concentrated alkaline aqueous solution, usually at a concentration of 50 to 80% by weight, so that the water content of the soap discharged from the outlet 1a is about 16% by weight or less, preferably 13 to 15% by weight, which does not require a drying process. used.

In addition to the above-mentioned fatty acids and alkaline aqueous solutions, various additives such as chelating agents, humectants, dyes, and perfumes can be used as raw material components, if necessary. These additives can be supplied simultaneously when the fatty acid and aqueous alkali solution are supplied into the reaction apparatus consisting of the kneader, or after the neutralization reaction has progressed to some extent or completely, and further from the reaction apparatus. It can be added to the discharged soap and mixed by any suitable means.

The soap obtained by the method of the present invention may be made into a product as it is, for example, in the form of pellets discharged from the kneading machine, or it may be further fed to an extruder equipped with another pro-ladder (cone part) and molded. It may also be made into a product by stamping.

〔Effect of the invention〕

As described above, in the present invention, fatty acids and a highly concentrated alkaline aqueous solution as raw materials are continuously supplied to a two-screw kneader having a kneading zone in which a number of paddles of a specific shape form a specific arrangement. By allowing the neutralization reaction to occur, the soap has a low moisture content that does not require a drying process after the neutralization reaction, and is uniformly neutralized, making it suitable for use in cosmetic soaps, etc. Very high quality soap can be obtained continuously.

〔Example〕

EXAMPLES Below, examples of the present invention will be described and explained more specifically. In the following examples, a continuous kneader manufactured by Kurimoto Iron Works ■ was used as a two-screw kneader.

Example 1 In the two-screw kneader shown in Figs. 1 to 3, the trough length was 4.
40IIm, a total of 24 paddles 4 having a convex lens cross section with a paddle diameter of 50mm are closely arranged and fixed on one rotating shaft 3a, including 12 helical paddles 4b and 12 flat paddles 4a, and fixed to the other rotating shaft 3b. A paddle 4 of the same diameter and the same number that forms a pair with each paddle 4 of the rotating shaft 3a with a phase difference of 90 degrees is used, and both rotating shafts 3a
, 3b were synchronously rotated in the same direction at a rotational speed of 9 Orpm, beef tallow fatty acid/
Coconut oil fatty acids - 8/2 (weight ratio) mixed fatty acids 300
84 g of a sodium hydroxide aqueous solution with a concentration of 56% by weight heated to 60°C from the raw material supply port 1b' at a rate of g/min.
It was fed at a rate of /min.

In this way, the neutralization reaction was completed in the twin-screw kneader, and the pellet-shaped soap was continuously discharged from the discharge port 1a.
Sampling was carried out every minute, and the water content and free alkali content were measured for a total of 100 samples. the result,
The water content is approximately 15% by weight in each case, and the free alkali content is 0.
．． Average about 0.03% by weight in the range of 0.02 to 0.05% by weight
Met. From these results, it was found that the above-described method can continuously and stably produce a low moisture content and uniformly neutralized soap without the need for a drying step.

Example 2 In the twin-screw kneader shown in Figs. 1 to 3, the trough length was 8.
00 Tsuru, a total of 36 paddles 4 having a diameter of 100 m and a convex lens-shaped shaft cross section are closely arranged and fixed on one rotating shaft 3a, including 16 helical paddles 4b and 20 flat paddles 4a, and fixed to the other rotating shaft 3b. Both rotating shafts 3a are formed by fixing paddles 4 of the same diameter and the same number that form a pair with each paddle 4 of the rotating shaft 3a with a phase difference of 90 degrees.

3b in the same direction at a rotation speed of 15 Orpm, hardened beef tallow fatty acid was heated to 70°C from the raw material supply port 1b at a rate of 500 g/min and heated to 60°C from the raw material supply port 1b'. A 72% by weight aqueous sodium hydroxide solution was fed at a rate of 100 g/min.

In this way, the neutralization reaction was completed in the twin-screw kneader, and the pellet-shaped soap was continuously discharged from the discharge port 1a.
Sampling was carried out every 10 minutes, and the water content and free alkali content were measured for a total of 50 samples. As a result, the water content was about 10% by weight in all cases, and the free alkali content was in the range of 0.03 to 0.07% by weight, with an average of about 0.05% by weight. From this result, Example 1 was obtained by the above method.
It has been found that it is possible to continuously and stably produce soap with a low moisture content and uniform neutralization similar to that in the case of .

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional side view showing an example of a twin-screw kneader used in the present invention, Fig. 2 is a cross-sectional plan view of the same, Fig. 3 is a cross-sectional view taken along line m-m in Fig. 2, Figures 4 (al to (di) are schematic sectional views sequentially showing the kneading operation of the same kneading machine, and Figure 5 (al
, (bl is a perspective view of a paddle used in the above kneading machine. A...2-shaft kneading machine, 3a, 3b... rotating shaft, 4
4a, 4b)...Paddle 4th Zl 5th (a) with a convex lens-shaped axial section

Claims (1)

[Claims] (1) In a two-shaft kneader, in which a large number of paddles with a convex lens cross section are fixedly attached to each shaft, forming a pair with a phase difference of 90 degrees between the two shafts, raw fatty acids and a highly concentrated alkaline aqueous solution are placed. 1. A method for producing soap, characterized in that soap that does not require a drying step is continuously produced by continuously supplying and carrying out a neutralization reaction.