JPH03279248A - Mold material and mold forming method - Google Patents

Abstract

PURPOSE:To obtain a material capable of readily forming a mold by casting close in physical properties to wooden mold and readily carrying out ejection after casting by blending gypsum and/or an alumina cement with a filler, alkylsulfonic acid salt, chelete agent, hydrophilic urethane and water at a specific ratio. CONSTITUTION:The aimed mold material is obtained by blending 100 pts.wt. gypsum and/or alumina cement with 0-1000 pts.wt. inorganic or organic filler, 0.001-1.0 pt.wt. alkylsulfonic acid salt or derivative thereof, 0.001-5 pts.wt. chelete agent, 0.5-15 pts.wt. hydrophilic urethane and 25-150 pts.wt. water. The hydrophilic urethane includes preferably a liquid polyurethane prepolymer having 1000-8000 molecular weight. The chelete agent includes EDTA.2Na, salts of citric acid or tartaric acid.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to industrially simple materials.

[Conventional technology and its issues]

Conventionally, materials and techniques related to molds have been used in various industrial fields, and there are a wide variety of methods.

In recent years, simple molds called model molds have attracted attention, particularly in the field of industrial design, and are used as models prior to manufacturing the actual product.

However, in the field of these mold materials, the conventionally used wooden molds, metal molds, plaster molds, clay molds, resin molds, etc. are easy to make, inexpensive, dimensionally stable, and impact resistant. Currently, no mold material with good workability has been found. For example, CSA.

There are few materials with good machinability and excellent dimensional stability that are suitable for three-dimensional machining using D SC and N.Currently, there are no particularly large molds, and high-quality wooden molds are not available in terms of wood resources. It is also difficult to obtain and expensive.

[Means to solve the problem]

The present invention was devised in view of the above-mentioned problems, and has physical properties similar to wooden molds, can be easily molded by casting, is inexpensive, and can be easily removed from the mold after casting and adheres to the other mold. The purpose of the present invention is to provide a material that can be molded into complex molds or even reverse tapers, and which cures quickly.

As a result of intensive studies on materials that satisfy these conditions, the inventors of the present invention have created a slurry by adding a predetermined amount of an appropriate filler, alkyl sulfonate, a chelating agent, and water to gypsum and/or alumina cement. The present invention was completed based on the discovery that the desired mold material could be obtained by adding hydrophilic urethane and appropriately controlling the gelation rate and hardening of gypsum and alumina cement.

That is, the present invention includes (A) 100 parts by weight of gypsum and/or alumina cement, (B) 1.0 to 1000 parts by weight of an inorganic or organic filler, and (C) 0.00 parts by weight of an alkyl sulfonate or a derivative thereof.
1 to 160 parts by weight (D) Chelating agent 0.001 to 5 parts by weight (E)
Hydrophilic urethane 0.5-15 parts by weight (F) water
The present invention relates to a molding material in which 25 to 150 parts by weight is added and a molding method using the molding material.

In the present invention, we devised a method to maintain physical properties similar to wood by using an alkyl sulfonate to adjust the gel time of hydrophilic urethane and a chelating agent to adjust the hardness. I was able to use it as an interview material. Furthermore, as a temporary molding material by injection, we discovered a method of adding and mixing an inorganic or organic filler, water, an alkyl sulfonate, and a hydrophilic urethane, and making it into an elastic molding material that can be cast and molded. .

The molding material and molding material of the present invention have high initial elasticity, about 500
% elongation, and there is little deformation of the mold during demolding and curing.
Since there is no damage, the present invention does not require conventional methods using split molds such as reverse taper, and by changing the formulation, it is possible to continuously exhibit physical properties ranging from elastic to soft to hard.

In other words, using plaster as an example, when the amount of hydrophilic urethane is constant, the amount of chelating agent is large = elastic, medium = soft, and small = hard. If the amount of hydrophilic urethane is changed, the amount of hydrophilic urethane is large = elastic. Body, medium = soft, small = hard.

It is also possible to set the change over time from elastic to soft to hard by changing the amount of chelating agent.

The gypsum used in the present invention may be either β-hemihydrate gypsum or α-hemihydrate gypsum, but since β-hemihydrate gypsum has somewhat poor dimensional stability, it is not suitable for applications that require a high degree of dimensional stability. The use of alpha hemihydrate gypsum is recommended. Dimensional stability can also be improved by mixing the two, mixing alumina cement, or adding an expanding agent for cement.

Further, as the filler to be mixed with these plasters, conventionally used inorganic and organic fillers can be used.

Examples include silica sand, silica powder, charcoal, talc, clay, slag, fly assini, bentonite, diatomaceous earth, perlite, barmculite, shirasu balloon, pulverized polystyrene foam, pulverized E[lA, pulverized urethane foam, etc.

In the present invention, the alumina cement includes various alumina cements, namely calcium aluminate compounds C, A SC2^, C3A XCzA.

Any suspension can be used as long as it contains CF, C, 2A7, etc., but it is preferred that the suspension has a pH of 12 or less.

Also, the filler used in mixture with alumina cement can be almost the same as that used in plaster.

Furthermore, in addition to using gypsum and alumina cement alone, it is also possible to use a mixture of the two as desired.
According to the purpose of the present invention, the gypsum:alumina cement ratio should be selected such that gypsum>alumina cement has good dimensional stability and gypsum<alumina cement has high strength.

In Kinobo and Akira, an expanding agent for cement can be used to reduce drying shrinkage for the purpose of achieving higher dimensional stability.

That is, it is possible to use an ettringite-based drying agent such as C3A or dibucal, and a polyhydric alcohol-based anti-drying agent.

The hydrophilic urethane used in the present invention is preferably a hydrophilic urethane that has a low NCO content, generates a small amount of CO2 gas in the gypsum and alumina cement slurry, and preferably has low drying shrinkage.

Therefore, it is preferable to use a block polymer in which the percentage of terminal incyanate is 2 to 6%, the EO:EO ratio of the polyol component is 100:0 to 30, and the arrangement of EO and PO is random rather than random. A water-soluble or water-dispersible urethane prepolymer obtained by reacting with a di- or polyisocyanate compound, preferably NC
A material is required that has a low O content, low foamability, high density when cured, a high EO content ratio, and good dimensional stability. A liquid polyurethane prepolymer having a molecular weight of 1,000 to 8,000 is easy to use. Specifically, there may be mentioned up-7008 (trade name) commercially available from Asahi Denka ■.

The amount of hydrophilic urethane relative to gypsum and alumina cement is 0.5 to 15%, preferably 1 to 10%. When such hydrophilic urethane is added to water, it gels in 30 seconds to 1 minute, resulting in short casting time and poor workability.

Therefore, in the present invention, in order to adjust the pot life, it is required to add a small amount of alkyl sulfonate or its derivative, which is a type of anionic surfactant, and thereby the pot life can be adjusted to 3 to 10 minutes. I can do it.

Furthermore, by adding a chelating agent at the same time, it became possible to freely adjust the elasticity retention time after gelation.

The amount of these ingredients is 10% of gypsum and alumina cement.
0 parts by weight, 0.001 to 1.0 parts by weight of the alkyl sulfonate or its derivative, chelating agent o, ooi~
5 parts by weight.

Normally, when hydrophilic urethane is added to hydraulic materials such as gypsum and alumina cement, after the hydrophilic urethane gels, the gel elasticity rapidly disappears and hardening progresses when the gypsum and alumina cement begin to set. The phenomenon of brittleness can be seen.

In order to prevent this, there is a method of using a large amount of hydrophilic urethane, but this is not preferable in terms of dimensional stability and heat resistance. Therefore, in order to maintain more effective elasticity for a long period of time using a small amount of hydrophilic urethane, a method of using a chelating agent is inexpensive and provides stable quality.

The alkyl sulfonate and its derivatives used in the present invention have water-reducing properties and chelating abilities, but this chelating ability is low and only has secondary elastic retention.

As the alkyl sulfonate and its derivatives, for example, alkylbenzene sulfonate, alkylnaphthalene sulfonate, and their aldehyde condensates are the most effective and preferably have less air entrainment.

At the same time, EDTA/2N is a strong chelating agent.
a. When 0.001 to 5 parts by weight of citrate, tartrate, phosphate, protein hydrolyzate, polycarboxylate, etc. are added to gypsum and alumina cement, the gypsum and alumina cement are completely coagulated. The cured product can maintain permanent elasticity because it acts as a dehydrating agent for the slurry.

When the purpose is to make a mold according to the present invention, the elasticity of the mold facilitates demolding and allows complex molding to be performed.

However, if the elasticity is too high as in the case of a silicone resin molding agent, the amount of deformation of the mold becomes large and the dimensional stability tends to deteriorate.

On the other hand, the present invention has the advantage that the hardness of the mold can be changed by controlling the amount of the chelating agent.

Conventionally, the production of foam by adding hydrophilic urethane to gypsum, alumina cement, and Portland cement has been disclosed in JP-A-56-96787 and JP-A-62-30.
As seen in Publication No. 84, these foams undergo large changes over time, and although they have initial flexibility, they become brittle for a while.

Kinobu and Akira solved this drawback, and in order to prevent this, it is necessary to use the retarder in an amount that is not used for the purpose of retarding setting, but as a softening agent, and it is necessary to improve the bending strength. A cured product with high impact resistance and good impact resistance can be obtained.

Therefore, the cured product obtained by the present invention is expected to be used not only as a molding material or molding material, but also as a synthetic wood and building material.

In addition, as anti-drying agents, polyhydric alcohols such as glycerin prepylene glycone ethylene glycol, PPG,
PEG or PEO and super absorbent resin are used.

When making a mold or making a mold material using the mold material of the present invention, the method of making the mold has a relationship with the mold to be molded. For example, if the surface of the mating mold has high water absorption, either water absorption or specific water absorption, surface treatment of the mating mold is required in order for the mold material of the present invention to have adhesive properties. Wood, paper, plaster, etc. are similar to this, and metals, plastic wax, etc. do not have adhesive properties, so there is no need for surface treatment. Use a mold release agent.

However, the hydrophilic urethane incyanate compound of the present invention has T, D, 1.・M, D, I, etc. are in the above range, but since the xylene diisocyanate compound has strong adhesive strength, a silicone-based or fluorine thread release agent is required.

In addition, the molded materials of the present invention have mutual adhesive properties and can be easily repaired and joined.

In the case of making a mold, hold the other mold with an appropriate spacer in advance and cast the mold. If you want to make a split mold, apply a mold release agent to the split surface, pour the mold on top of it, and make the split mold. shall be. In this case, for molds that are difficult to demold, such as reverse tapering, the amount of hydrophilic urethane and chelating agent are increased to increase elasticity and facilitate demolding.

The mold material produced in this way has good transferability and can create patterns that are difficult to make with fine conventional plaster. A wooden mold can be made by casting. In addition, for mold dimensions such as forging molds and press molds, cast into the upper, lower, and mold, and then combine both molds.
After bonding, you can remove the mold and check the precision of the mold.

This also applies to resin molds, and since they do not have the brittle physical properties of plaster, they can also be molded from thin materials such as paper.

Furthermore, the molding material of the present invention can be easily molded into a mold as flexible as the human body, and since it is less toxic to the human body, direct molding can be performed.

For example, it is easy to make molds of various medically necessary devices such as flat molds and foot molds, death masks, body shapes, etc., and because it is elastic, it can be molded and removed more faithfully than plaster or plaster-impregnated bandages.

In other words, if another type of material is to be cast into the mold within a short period of time after the mold is made, this method is fully suitable for the purpose.

However, it does not have the physical properties that can withstand long-term storage like wooden molds or metal molds, nor does it have sufficient dimensional stability.

In the present invention, the amount of water blended is 50 to 1000 parts by weight, preferably 100 to 5 parts by weight, per 100 parts by weight of hydrophilic urethane.
00 parts by weight (25 to 150 parts by weight for 100 parts by weight of gypsum and/or alumina cement, preferably 30 to 1
00 parts by weight). It is preferable to premix the water by adding a filler, a gelation retarder such as an alkyl sulfonate, a drying shrinkage inhibitor, etc. in advance.

When pre-mixing these materials, it is necessary to maintain fluidity for easy casting, although this will vary depending on the powder level.

〔Effect of the invention〕

The mold material of the present invention is different from conventional mold materials, and can be easily and inexpensively manufactured with good workability.

〔Example〕

The present invention will be explained in more detail with reference to Examples below. still,
In the examples, all parts represent parts by weight.

Example 1 A mixture of 100 parts of calcined gypsum (B manufactured by Yoshino Gypsum) and 100 parts of calcium carbonate (Whiten manufactured by Shiraishi Kogyo ■) was ET
A slurry was prepared by adding 3 parts of D^2NaO, 0.2 part of Rebellon (cement water reducing agent manufactured by Sanyo Chemical Co., Ltd.), 1.0 part of diethylene glycol, and 100 parts of water using a mixer.

Add hydrophilic urethane (up-70 manufactured by Asahi Denka ■) to this slurry.
08) Add 15 parts and mix rapidly, 40 parts after 30 seconds.
It was cast into a mold of 40 x 160 mm.

It turned into a gel after about 3 minutes and could be removed from the mold after 5 minutes.

The elasticity disappeared after 2 days, but there was no brittleness. After 28 days, the bending strength was 96kg/cn! , compressive strength 164kg
/cIII, impact strength 7.6 kgf cm/crl, this cured product could be worked with woodworking tools such as saws, planes, and joints, and was flame retardant.

Comparative Example 1 100 parts of the same gypsum as Example 1, 100 parts of calcium carbonate
The mixture was added to 100 parts of water and rapidly mixed with 15 parts of hydrophilic urethane (same as in Example 1) as a slurry in a mixer, and after 20 seconds it was cast into a 40 x 40 x 160 mold. 20 minutes after casting, heat was generated, and the plaster hardened and lost its elasticity, and became brittle after 5 days.

Physical properties on the 28th were bending strength of 23 kg/cd and compressive strength of 18.
6kg/cut, impact strength 1.6kgf/c11
! It is. In this example, the gelation of the hydrophilic urethane was very fast and the casting time was too short, resulting in embrittlement and no difference from the hardened plaster.

Comparative Example 2 A mold material was produced in the same manner as in Example 1 except that EDTA/2Na was not added, and the gelation time was 3.
After 20 minutes, heat was generated and the plaster hardened, and after 3 days it began to become brittle and its elasticity completely disappeared after 14 days.

Example 2 100 parts of α-gypsum hemihydrate was preliminarily mixed with 1 Og of potassium tartrate.
, Mighty (cement water reducer manufactured by Kao ■) 2, Qcc
was added to 50 cc of water in which it was dissolved and mixed to form a slurry.

Hydrophilic urethane (up-7008 manufactured by Asahi Denka ■) 3
．． When 0 g was added, mixed rapidly and cast, the mixture gelled in 3 minutes and 40 seconds and became an elastic body. This at 70℃
It was dried for several days and used as a specimen. Specific gravity 1.9 Bending strength 12
1kg/c[+t, compressive strength 206kg/cfIt, impact strength 8.8 kg cm/cnf, linear expansion coefficient 7
．． IXl0-5.

The cured product of this example has physical properties and processability similar to wooden molds.

Comparative Example 3 A sample was prepared using the same weight part of the same formulation as in Example 2, except that the hydrophilic urethane was replaced with Polygrout 1 (manufactured by Dai-Kogyo Seiyaku).

This cured product had a specific gravity of 1.2 and was similar to foam and had many bubbles, so it had low bending and compressive strength and poor dimensional stability.

Example 3 Asano Alumina Cement No. 1 (manufactured by Nippon Cement ■) 50
and 50 parts of heavy coal, and to this were mixed 0.2 parts of Rebellon (cement water reducing agent made by Sanyo Chemical Co., Ltd.), 1.0 part of sodium citrate, and 2. 5 parts and 50 parts of water were added and mixed to form a slurry. To this slurry, 5.0 parts by weight of hydrophilic urethane (up-7008 manufactured by Asahi Denka Kogyo Corporation) was added, rapidly mixed, and poured into a 40 x 40 x 160 mold.

It gelated after about 7 minutes, was removed from the mold after 10 minutes, and was air-cured for 28 days to prepare a specimen. Bending strength 175kg/
cffl, compressive strength 380kg/cut, impact strength 6.
3 kgcm/crl, pencil hardness 4H1 linear expansion coefficient 4.
3XIO-5, the shrinkage rate during curing was 2.2%, and the cured product of this example had higher hardness and strength than the cured gypsum products of Examples 1 and 2, and had physical properties close to those of plastic.

Comparative Example 4 When the amount of citric acid NA was reduced to 0.1 part from the formulation of Example 3, the physical properties under the same curing conditions were flexural strength of 115 kg/c
ffI, compressive strength 417 kg/c++f, impact strength 2.
6 and became brittle.

Example 4 40 parts of calcined gypsum (Sannis plaster ■Type B) and 60 parts of Asano alumina cement (No. 1 manufactured by Nippon Cement ■) were mixed,
This was mixed with 1.0 part of Polity N-100 (Lion-Cement water reducer), 1.0 part of ETOA.2Na, and 50 parts of water to form a slurry. 5.0 parts of hydrophilic urethane (UP-7008, manufactured by Asahi Denka Kogyo Corporation) was added to this slurry, mixed rapidly, and cast into a mold of 40 x 40 x 160 mm.

After about 5 minutes, it gels and becomes an elastic body, and after 3 minutes it can be removed from the mold. When the prepared specimen was cured in air for 28 days and then subjected to physical property tests, the specific gravity was 2.3, the length change rate over 28 days was 1.2%, the bending strength was 173 kg/cut, and the compressive strength was 281 kg/co! , impact strength 6.4kgcm/
It was crl.

Example 5 100 parts of fly ash, 1.0 part of Levelon (cement water reducer manufactured by Sanyo Chemical Co., Ltd.) and 0.0 part of polyethylene oxide
1 part was mixed and 50 parts of water was added thereto to form a slurry.

Add hydrophilic urethane (Asahi Denka Kogyo uJ) to this slurry.
70'08) 20 parts by weight were added, rapidly mixed, and poured into a mold placed in a mold, and after 4 minutes, it gelled to form an elastic body. After 5 minutes, the mold was removed and the mold-making work was completed.

Apply soap water to this molded surface and apply 1 part of calcined plaster to this.
When a gypsum slurry consisting of 0.00 parts and 50 parts of water is cast,
The shape in the formwork in which the above-mentioned mold-making work was performed could be transferred to plaster.

Comparative Example 5 Among the formulations of Example 5, when molding was performed with a formulation excluding Rebellon and polyethylene oxide, gelation took 50 seconds, making it difficult to cast and drying shrinkage started in a short time. Therefore, the dimensional stability was poor.

Example 6 100 parts of super grout main agent (acrylate solution manufactured by Toagosei Kagaku Kogyo ■), 100 parts of calcined gypsum (sunnis gypsum type 4B), and 3.0 parts of glycerin were mixed to make a slurry. 1.0 part grout additive to 10 parts water
An aqueous solution of a polymerization catalyst prepared by dissolving 0.5 parts of a super grout accelerator in 10 parts of water was added, rapidly mixed, and poured into a mold. After 5 minutes, the mixture gelled into an elastic body.

Although this cured product gradually dries in the air and becomes brittle, it has sufficient elasticity for a short period of time and can be used as a molding material.

Comparative Example 6 The gelled product of Example 6, which had the same composition of the super grout base agent, super grout additive, accelerator, and water but excluded calcined gypsum and glycerin, had large syneresis and drying shrinkage, resulting in poor dimensional stability. It could not be used as a molding material.

Example 7 50 parts of β-calcined gypsum, 50 parts of α-calcined gypsum, Polity N-1
00 (alkylnaphthalene sulfonic acid condensate manufactured by Lion) and 1.0 part of ETDA・2Na were mixed in powder form, and this was added to a solution of 50 parts of water and 1.5 parts of polyethylene glycol (molecular weight 500). The mixture was added and mixed to form a slurry.

Hydrophilic urethane (up-7008 manufactured by Asahi Denka Kogyo ■)
7 parts were added and rapidly mixed.

When this slurry was poured into a mold with pre-wrapped legs placed in it, it gelled after 3 minutes and the legs were removed after 5 minutes. This foot shape is made of epoxy resin (εP manufactured by Asahi Denka Kogyo Co., Ltd.)
-4200) 100 parts of sawdust and 10 parts of sawdust were defoamed, and 40 parts of an epoxy resin curing agent (EH-240 manufactured by Asahi Denka Kogyo) was mixed and poured. It is better to apply a molding agent). After 2 hours, the mold was removed and a phase model was completed.

Example 8 A pre-prepared two-part Daruma mold was set on a potter's wheel with the head down and the feet up as an injection port, and while rotating at 120 revolutions per minute, 100 parts of calcined gypsum was poured into the mold. A mixture of 100 parts of heavy calcium carbonate was added to a solution in which 1.0 part of Rebellon (cement water reducing agent manufactured by Sanyo Chemical Industries, Ltd.) and 1.0 part of potassium tartrate were dissolved in 100 parts of water and mixed to form a slurry. . Add hydrophilic urethane (Asahi Denka Kogyo ■) to this slurry.
UP-7008) was added thereto, and the rapidly mixed slurry was poured into the rotary mold to perform molding.

After 5 minutes, the rotation was stopped and the mold was removed, yielding a hollow Daruma.

Example 9 Wooden carvings were set in the formwork, and heavy calcium carbonate 1
00 parts, Polity N-100 (lion flank cement water reducer) 1.0 parts, water 50 parts, propylene glycol 1.0 parts.
5 parts of the solution was mixed to form a slurry, to which 20 parts of hydrophilic urethane (up-7008 manufactured by Asahi Denka Kogyo ■) was added, rapidly mixed, and poured into the mold.

It turned into a gel after 3 minutes, and after 5 minutes, part of the reverse taper was released from the mold while being stretched. Apply soap water to the transferred picture frame surface, add 100 parts of α-calcined gypsum, 100 parts of heavy calcium carbonate,
A mixture consisting of 2 parts of Polity N-1000 and 0.1 part of Pufftart (gypsum retarder manufactured by Ajinomoto Co., Ltd.) was added to 80 parts of water and mixed to prepare a slurry. 6 parts of the hydrophilic urethane and 2 parts of diethylene glycol were added to this slurry, mixed rapidly, and poured into the transfer picture frame mold. After 4 minutes, it turned into a gel, and after 8 minutes, the mold was gently removed using its elasticity. did. The surface of the frame made in this way was painted, and a frame exactly the same as the previous wooden frame was easily obtained.

Claims (1)

[Scope of Claims] 1 (A) 100 parts by weight of gypsum and/or alumina cement (B) 1.0 to 1000 parts by weight of an inorganic or organic filler (C) 0.001 parts by weight of an alkyl sulfonate or its derivative
-1.0 parts by weight (D) 0.001 to 5 parts by weight of chelating agent (E) 0.5 to 15 parts by weight of hydrophilic urethane (F) 25 to 150 parts by weight of water. 2. A mold making method using the mold material according to claim 1.