JPS61146199A - Production of porous molded body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for manufacturing a porous molded body.

<Prior Art> Many materials have been known as porous molded bodies, such as porous pottery, refractories, porous glass, porous metals, and porous polymers. Table 1 below summarizes their types and characteristics, but each method requires a large amount of production equipment and complicated production processes, and cannot be produced at low cost.

Table 1 <Problems to be solved by the invention> The purpose of the present invention is to provide a method for manufacturing a porous molded article inexpensively and easily by using lactose as a raw material and processing it in an appropriate manner. shall be.

Means to solve problems〉 The present invention will be explained in detail below.

The porous material of the present invention can be produced by adding and mixing alcohol such as ethyl alcohol to anhydrous lactose to make it liquid, then injecting it into a suitable mold and solidifying it. After solidifying, the alcohol is removed by drying, and the alcohol is vaporized. It is obtained by a method of imparting porosity.

The use of anhydrous lactose is a critical requirement in the present invention. Normally, lactose is obtained as an α-hydrate as a crystal at room temperature, but when producing anhydrous lactose, this crystalline lactose is dried at 93°C or higher by appropriate means such as spray drying or dry heat drying. Obtain lactose (βm). This anhydrous lactose is obtained by removing crystal water molecules from the molecular structure of crystalline lactose.

As the additive liquid for producing liquid anhydrous lactose, alcohols are most preferable, and specifically, ethyl alcohol is most preferable. Further, alcohol is most preferably completely anhydrous, but it is practically acceptable as long as the water content is within 1%. If the moisture content is 1% or more, the strength of the molded product will be significantly reduced or it will not solidify.

Next, the mixing ratio of anhydrous lactose and alcohol is 1:1 to 4 (
molar ratio) is most preferable. When the mixing ratio is less than 1:1, uniform dispersion is difficult and the mixture does not appear liquid, making it difficult to pour into a mold. Further, if the mixing ratio exceeds 1:4, solidification takes a long time and the strength of the molded product decreases significantly.

The method of mixing anhydrous lactose and alcohol is not particularly limited as long as it can be mixed uniformly into a liquid state, such as by stirring.

This liquid material is poured into a predetermined mold and allowed to stand in an atmosphere of about 40 to 50° C. for about 24 hours to solidify.

The solidified molded product is removed from the mold.

The porous molded article of the present invention is obtained by drying at a temperature equal to or higher than the boiling point of the alcohol used or by drying under reduced pressure to remove the alcohol. The openings at that time are caused by the alcohol vaporization passage.

<Effect of the invention> The present invention has the following effects.

■ Lactose 1 (crystalline lactose) has a specific gravity of 153, which is naturally light; however, the bulk specific gravity of the porous material obtained by the present invention is around 1.0, which is extremely light.

■ The porosity is continuous pores.

(2) The porosity varies depending on the initial amount of alcohol added, but is 20 to 50%.

■ Pore diameter varies slightly depending on drying temperature conditions.

If the temperature is kept at low temperature for a long time, please take detailed steps 1. In addition, when the temperature is high for a short time, it tends to become rough, but it has a distribution of about 1μ to 10μ.

■ Excellent one-dimensional stability with no volume change (shrinkage or expansion) before and after alcohol vaporization.

■ Since it contains lactose, its wear resistance is poor.

It has excellent strength in compression and tension, and can be used in fields where durability is not required.

■ In addition, in the manufacturing method, porosity was conventionally formed by methods such as sintering, acid treatment, and addition of foaming agents, but according to this method, it can be easily obtained by drying alcohol. The manufacturing process is significantly simpler than before.

In order to increase the strength of the porous body of the present invention, it is also possible to add a small amount of a binder such as alcohol-soluble polyvinyl alcohol, polyamide, polyester acrylic, epoxy, or vinyl acetate.

The present invention can be expected to have many uses. Particularly when used in vacuum molding or pressure molding, it has better air permeability than conventional wooden molds or resin molds, so small holes and vent plugs are not required, simplifying mold production compared to conventional molds.

This will be described in detail in Examples below.

Example 1 Powdered anhydrous lactose (β-lactose) 20J9 was obtained by spray drying at 100° C. to a moisture content of 1.0%.

Anhydrous ethyl alcohol 549 was mixed and stirred in a beaker to form a muddy liquid, and then dried at 50°C for 24 hours to obtain an ethyl alcohol-containing solid.

This was further dried at 70°C for 24 hours to completely vaporize and remove the alcohol contained, thereby obtaining a product of the present invention.

Next, the surface and internal cross sections of the product of the present invention were observed using an electron microscope, and it was found that the product had continuous pores of several microns in size.

In addition, the porosity (percentage of pore volume to total volume (m17ml)) of the products of the present invention was determined by the helium substitution method, and the porosity was 25% - Comparative Examples 1 to 5 Same as Example 1 Using the method described above, various solvents or water were added and mixed in place of alcohol to form a slurry, which was then left to stand to observe changes in shape. The results are shown in Table 2.

Table 2 Example 2 The relationship between the amount of ethyl alcohol added and the porosity was investigated in the same manner as in Example 1. The results are shown in Table 3.

Table 5

Claims (1)

[Claims] 1) Add and mix anhydrous alcohol with a water content of 1% or less to anhydrous lactose from which water of crystallization has been removed based on its molecular structure, leave the resulting anhydrous lactose-anhydrous alcohol mixture to solidify, and further remove the alcohol contained. A method for producing a porous molded body characterized by: