JP2008137839A - Method for producing inorganic molded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an inorganic molded body where, when an inorganic molded body is produced by molding a cement based molding material composed of a cement-containing inverse emulsion composition including cement, water and a styrene monomer, and maturing and curing the same, the remaining quantity of the styrene monomer can be efficiently reduced. <P>SOLUTION: A molded body obtained by molding a cement based molding material composed of a cement-containing inverse emulsion composition including cement, water, a styrene monomer and an emulsifying agent is heated at 80 to 100°C, is matured and cured, and is subsequently heated at 110 to 140°C. The polymerization of the styrene monomer can be promoted by the heating after the maturing and curing of the molded body, and the remaining quantity of the styrene monomer in the inorganic molded body can be reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an inorganic molded body in which a molded body obtained by molding a cement-based molding material comprising a cement-containing inverse emulsion composition containing cement, water, and a styrene monomer is cured and cured.

  Cement-based molded articles formed by extrusion molding or the like are widely used as building materials because they are excellent in weather resistance and fire resistance and have low production costs.

  As an effective method for producing an inorganic molded body such as a cement-based molded article, a method using a cement-based molding material containing water, a hydraulic cement and an inverse emulsion (W / O emulsion) containing a styrene monomer and an emulsifier is proposed. Has been. This cement-based molding material is excellent in shape retention during molding and has the feature that the specific gravity of the cement-based molded product can be freely controlled by changing the water / cement ratio. .

When producing an inorganic molded body that can be applied to ceramic-type exterior materials and interior materials with such a cement-based molding material, the cement-based molding material is molded into a desired shape and desired on the outer surface as necessary. A pattern having the following shape is formed, and the cement is hydrated and cured by steam curing or the like and a styrene monomer is copolymerized (see Patent Document 1).
JP 2006-124231 A

  However, in the curing and curing process of the molded body, it is difficult to react all of the styrene monomer in the cement-based molding material, and there is a possibility that unreacted styrene monomer may remain in the inorganic molded body.

  Here, since the boiling point of the styrene monomer is 145 ° C., it is considered that the styrene monomer is volatilized by heating the inorganic molded body after curing at a temperature exceeding 145 ° C. It is necessary to consume energy. In particular, when water remains in the inner part of the inorganic molded body, it is difficult to heat the inorganic molded body to 100 ° C. or higher, and therefore more energy is required to remove moisture from the inorganic molded body. At the same time, heating for a long time is required and the production efficiency is also lowered. In addition, the polymer structure of styrene in the inorganic molded body may be destroyed by high-temperature heating.

  The present invention has been made in view of the above points, and forms an inorganic molded body by molding a cement-based molding material composed of a cement-containing inverse emulsion composition containing cement, water, and a styrene monomer, and curing and curing it. It is an object of the present invention to provide a method for producing an inorganic molded body capable of efficiently reducing the residual amount of styrene monomer in production.

  The manufacturing method of the inorganic molded object which concerns on Claim 1 heats the molded object which shape | molded the cement-type molding material which consists of a cement containing inverse emulsion composition containing cement, water, a styrene monomer, and an emulsifier at 80-100 degreeC, and healed it. It is characterized by heating to 110-140 ° C. after curing.

  The invention according to a second aspect is characterized in that, in the first aspect, after the molded body is heated, the molded body is exposed under reduced pressure.

  The invention according to claim 3 is characterized in that curing curing is performed in an autoclave in claim 1 or 2.

  According to the first aspect of the invention, the polymerization of the styrene monomer can be promoted by heating after curing and curing the molded body, and the residual amount of the styrene monomer in the inorganic molded body can be reduced.

  According to the invention which concerns on Claim 2, the styrene monomer in a molded object is volatilized by putting a molded object under reduced pressure, and the residual amount of a styrene monomer can further be reduced.

  According to the invention which concerns on Claim 3, a molded object can be steam-cured within an autoclave, and the heating of the molded object after curing can also be performed continuously within an autoclave. Furthermore, when the molded body is placed in a reduced-pressure atmosphere after heating, the temperature inside the autoclave can be lowered to reduce the volume of the gas inside, and the vapor can be condensed to easily reduce the atmosphere around the molded body. It can be done.

  The best mode for carrying out the present invention will be described below.

  The cement-based molding material used in the present invention is composed of a cement-containing inverse emulsion composition mainly composed of cement, water, and styrene monomer.

  This cement-based molding material is prepared by first mixing an emulsifier, a styrene monomer, water, a crosslinking agent, and a polymerization initiator to prepare an inverse emulsion (W / O emulsion). Next, the cement, a lightening agent, It can be obtained by adding reinforcing fibers and mixing with a forced stirrer or a continuous mixer.

  Here, as the emulsifier, for example, nonionic such as oleic acid type emulsifier, coconut oil type emulsifier, sorbitan sesquioleate, glycerol monostearate, sorbitan monooleate, diethylene glycol monostearate, sorbitan monostearate, diglycerol monooleate Surfactants, various anionic surfactants, cationic surfactants and the like can be used.

  Moreover, as a crosslinking agent, a trimethylol propane trimethacrylate etc. can be used, for example.

  Moreover, as a polymerization initiator, polymerization initiators, such as an organic peroxide and a persulfate, for example, t-hexyl peroxy-2-ethylhexanoate etc. can be used.

  The emulsifier content is 2.0 to 5.0% by weight, the styrene monomer content is 8.0 to 17.0% by weight, and the water content is 77.0 to 89% with respect to the total amount of the inverse emulsion. 0.0% by weight, the content of the crosslinking agent can be set to 0.04 to 0.6% by weight, and the content of the polymerization initiator can be set to 0.04 to 0.6% by weight.

  The cement is not particularly limited, but Portland cement, fly ash cement, blast furnace cement, alumina cement, high alumina cement, slag cement, early strength cement, silica fume, etc. can be used. It can be used alone or in combination of two or more.

  Moreover, as a weight reduction material, organic foams, such as an acrylonitrile foam, a polystyrene foam, a polyvinylidene chloride foam, etc. other than fly ash balloon, pearlite, shirasu balloon, etc. can be used, for example.

  Moreover, as a reinforcing fiber, a polypropylene fiber, an acrylic fiber, a vinylon fiber etc. can be used, for example.

  And the cement content is 70 to 99% by weight, the light weight material content is 0.3 to 30% by weight, and the reinforcing fiber content is 1.0 to 2.0% with respect to the total amount of the cement-based molding material. It can be set to% by weight.

  Next, a method for producing an inorganic plate using the cement-containing inverse emulsion composition as a cement-based molding material will be described.

  First, a molded body is produced by molding a cement-based molding material into a plate shape or the like. The molded body can be molded by commonly used means such as a casting method, an extrusion molding method, an injection molding method, and a press molding method.

  Next, the molded body is cured and cured. When performing curing and curing, the molded body is heated until it reaches 80 to 100 ° C., and at this time, it is preferably heated for 6 to 15 hours. At this time, the molded body is preferably steam-cured in an autoclave, but the molded body may be heated by any other appropriate means. Here, if the temperature of the molded body during curing is less than 80 ° C., the molded body cannot be sufficiently cured, and if the temperature of the molded body exceeds 100 ° C., the molded body is swollen. It will end up.

  Next, the shaped body is heated until reaching a temperature of 110 to 140 ° C., particularly preferably a temperature of 120 ° C. At this time, if the molded body reaches the predetermined temperature, the molded body may be quickly taken out without maintaining the state, and is held for an appropriate time (for example, 5 hours or less) after reaching the temperature. You may do it. Here, when the molded body is steam-cured in the autoclave, the molded body can be continuously heated in the autoclave. By heating in this way, even if the styrene monomer remains in the molded body, the polymerization reaction of the styrene monomer is promoted, and the residual amount of styrene monomer is reduced. At this time, if the heating temperature is less than 110 ° C., the polymerization of the styrene monomer cannot be promoted sufficiently, and if it exceeds 140 ° C., the polymer structure of styrene in the molded product may be destroyed. Moreover, it is preferable to make the atmospheric pressure around a molded object into the range of 143-361 kPa at the time of this heating. When moisture remains in the molded body, it becomes difficult to uniformly heat the molded body up to the inside, but if the atmosphere around the molded body is pressurized as described above, the molded body Can be heated to a uniform high temperature to the inside, the reaction of the styrene monomer can be promoted over the entire molded body, and the remaining of the styrene monomer can be further suppressed.

  Here, when the molded body is heated at 110 to 140 ° C. from the beginning at the time of curing and curing, there is a problem that the molded body is swollen, but after the curing and curing is first performed at 80 to 100 ° C. as described above, 110 to Heating at 140 ° C. allows curing and curing without adversely affecting the molded product, and can promote the polymerization of styrene monomer in the resulting inorganic molded product and reduce the residual amount of styrene monomer It is.

  Moreover, after heating the molded body in this manner, it is preferable to further expose the molded body to a reduced-pressure atmosphere. In this case, the styrene monomer remaining in the molded body can be volatilized, and the residual amount of styrene monomer in the obtained inorganic molded body can be further reduced. Here, if the styrene monomer is volatilized simply by heating the molded body, the boiling point of the styrene monomer is 145 ° C., and when moisture remains in the molded body particularly at normal pressure. Although it is difficult to volatilize styrene by heating to a depth of 145 ° C. or more to the inside of the molded body, as described above, the molded body is exposed to a reduced pressure atmosphere without heating the molded body to a high temperature. Styrene monomer can be stripped. At this time, in order to sufficiently volatilize the styrene monomer from the molded body, it is preferable to expose the molded body to a reduced-pressure atmosphere of 31 kPa or less. Moreover, it is preferable that the atmospheric temperature at this time shall be the range of 30-70 degreeC.

  When the molded body is steam-cured in the autoclave when the molded body is exposed to a reduced pressure atmosphere in this way, the autoclave is lowered by lowering the temperature in the autoclave while the autoclave is sealed after the molded body is heated. The inside can be depressurized. At this time, the volume of the air in the autoclave decreases as the temperature decreases, and the vapor sealed in the autoclave condenses, reducing the atmosphere around the compact without performing suction or the like for decompression. Is something that can be done.

(Example 1)
Ordinary Portland cement 72.30 parts, Lightweight material (acrylonitrile organic foam) 20.00 parts, Polypropylene fiber 1.00 parts, Styrene monomer 5.00 parts, Oleic acid emulsifier 1.20 parts In addition, 0.50 parts by weight of additives (polymerization initiator and crosslinking agent) and 50.00 parts by weight of water were mixed and kneaded with an Eirich mixer, and then extruded to have a size of 10 mm × 150 mm × 300 mm. A molded body was obtained.

  This molded body was cured and cured in an autoclave. At this time, the molded body was first heated from 30 ° C. to 60 ° C. over 2 hours, held at 60 ° C. for 8 hours, then heated to 90 ° C. over 2 hours, and then 11.6 at 90 ° C. Held for hours.

  Thereafter, the compact was heated to 120 ° C. in an autoclave for 0.4 hours and the pressure in the autoclave was increased to 198.5 kPa (1489 mmHg), and then taken out from the autoclave to obtain an inorganic compact.

(Example 2)
After curing and heating the molded body in the same manner as in Example 1, the temperature in the autoclave was lowered to bring the molded body to 100 ° C. over 0.2 hours, and then 60 ° C. over 0.3 hours. I made it. At this time, the pressure in the autoclave was 19.9 MPa (149 mmHg). Thereafter, the molded body was taken out from the autoclave to obtain an inorganic molded body having the same dimensions as in Example 1.

(Comparative Example 1)
The molded body molded in the same manner as in Example 1 was cured and cured. At this time, the molded body was first heated from 30 ° C. to 60 ° C. over 2 hours, held at 60 ° C. for 8 hours, then heated to 90 ° C. over 2 hours, and then held at 90 ° C. for 12 hours. did. Thereafter, the molded body was taken out from the autoclave without further heating, and an inorganic molded body having the same dimensions as in Example 1 was obtained.

(Evaluation test)
The specific gravity and bending strength of the inorganic molded bodies obtained in Examples 1 and 2 and Comparative Example 1 were measured. At this time, as bending strength, three-point bending strength was measured under the conditions of a span of 100 mm and a test speed of 2 mm / min.

For each of the inorganic molded bodies obtained in Examples 1 and 2 and Comparative Example 1, a sample having a size of 5 mm × 15 mm × 90 mm was cut out and placed in a glass sample tube having a capacity of 120 cm ³ and sealed. After heat-processing this at 60 degreeC for 2 hours, the gas in a sample tube was extracted with the syringe, and the styrene density | concentration in this gas was measured with the detection tube.

  The results are shown in Table 1.

  As a result, the residual amount of styrene monomer was less in Example 1 than in Comparative Example 1, and no styrene monomer was detected in Example 2.

Claims (3)

  Heating a molded body obtained by molding a cement-based molding material composed of a cement-containing inverse emulsion composition containing cement, water, a styrene monomer, and an emulsifier to 80 to 100 ° C., followed by heating to 110 to 140 ° C. A method for producing an inorganic molded body, characterized in that   The method for producing an inorganic molded body according to claim 1, wherein the molded body is exposed to a reduced pressure after the molded body is heated.   Curing and curing are performed in an autoclave. The method for producing an inorganic molded body according to claim 1 or 2.