JP2002011544A - Composition for molding sweeping mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for molding a sweeping mold having good moldability and compressive strength of kneaded sand. SOLUTION: This composition for molding the sweeping mold consists of an aggregate (A), an alkali resol type phenol resin (B) and a water soluble macromolecule (C) of one or more kinds selected from cellulose derivative series, protein series, polysaccaride series, polyvinyl series, polyacrilic acid series and polyurethane series.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for shaping and shaping having excellent moldability.

[0002]

2. Description of the Related Art A method of molding a cylindrical or three-dimensionally curved mold for a medium-sized or large-sized casting in a large variety of small-quantity production is called a scraping mold or a turning mold. There is a molding method (this is called a shaving molding method). For example, in the case of a large-diameter pipe, kneading sand is filled and piled up in an iron mold, and a shaving plate is formed around the axis of the pipe. Swirl to remove the sand and mold the outer mold. Conventionally, cement and water added to sand, which is aggregate,
Although inorganic binders such as water glass have been used, alkali resole type phenolic resin binders have attracted attention from the viewpoint of reusability and moldability.
No. 95 discloses a method of combining aggregates having different particle sizes, and JP-A-9-122819 discloses a method of using bentonite in combination. However, the moldability of the kneaded sand and the compressive strength were not sufficient.

[0003]

SUMMARY OF THE INVENTION The present invention provides an aggregate (A),
Oyster containing at least one water-soluble polymer (C) selected from alkali resole type phenolic resin (B), cellulose derivative type, protein type, polysaccharide type, polyvinyl type, polyacrylic acid type and polyurethane type It relates to a composition for molding.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As the aggregate (A), various types have conventionally been used according to the purpose of casting. For example, natural silica sand, artificial silica sand, ceramic particles such as alumina, zircon sand, chromite sand , Olbin sand and the like.

[0005] Alkaline resole type phenolic resin (B)
Is preferably contained in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the aggregate (A) from the viewpoint of mold strength and disintegration after casting.

Alkali resole type phenolic resin (B)
Is obtained by subjecting a phenol to a condensation reaction with an aldehyde in the presence of an alkaline catalyst.

Examples of the phenols include alkylphenols such as phenol, cresol, xylenol, butylphenol and isopropenylphenol, polyhydric phenols such as resorcinol, catechol and hydroquinone;
Bisphenols such as bisphenol A and bisphenol F are used. These phenols may be reacted with aldehydes alone or in combination of two or more.

As the aldehyde compound bound to phenols, formaldehyde, paraformaldehyde, furfural, glyoxal and the like are used. As a reaction catalyst, potassium hydroxide, sodium hydroxide,
Lithium hydroxide and the like are exemplified.

Alkaline resole type phenolic resin (B)
Usually has a resin content of preferably 25 to 90% by weight,
It is more preferably used as a 35 to 70% by weight aqueous solution, and the aqueous solution may contain a known silane coupling agent in order to improve the strength of the mold. As the silane coupling agent, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ- (2-aminoethyl) aminopropyltrimethoxysilane are preferable.

A conventionally known binder resin, for example, a resol type phenol aldehyde resin may be used in combination with the alkali resole resin (B).

Examples of other additives that can be added to the composition of the present invention include solvents such as alcohols, glycols and ether alcohols.

Examples of the curing agent for curing the alkali resole resin (B) mixed with the aggregate include lactones such as γ-butyrolactone and ε-caprolactone;
Organic esters of 0 monohydric or polyhydric alcohols and a carboxylic acid having 1 to 10 carbon atoms can be exemplified. About the compounding amount of the curing agent, the alkali resole resin (B)
Is preferably 10 to 50% by weight, more preferably 15 to 30% by weight. In this range, sufficient curing is achieved.

Further, by adding 0.1 to 30 parts by weight, preferably 3 to 15 parts by weight, of the oxyanion compound to 100 parts by weight of the alkali resole resin (B), the composition can be cured with carbon dioxide gas. Examples of the oxyanion compound include boric acid, borate compounds such as sodium tetraborate decahydrate (borax), potassium tetraborate decahydrate, sodium metaborate, sodium pentaborate, and other borate compounds; aluminates; Acid salts and the like. The amount of carbon dioxide used is 0.01 to 30 parts by weight, preferably 0.1 to 30 parts by weight, per 100 parts by weight of the aggregate (A) in order to prevent uncuring of the mold and to maintain the productivity of the mold. 15 parts by weight. The carbon dioxide gas may be aerated by a reduced pressure substitution hardening method. Examples of the alkali resole resin for curing carbon dioxide gas are disclosed in Japanese Patent Publication No. 4-76947 and Japanese Patent No. 2723376.

Further, an organic ester curing method and a carbon dioxide gas curing method may be used in combination. That is, an organic ester is added to an alkali resole resin containing an oxyanion compound, and after shaping, a carbon dioxide gas is blown to accelerate the curing of the mold.
At this time, by using an organic ester curing agent and an epoxy compound together, the curing speed and the pot life can be adjusted, and the mold strength can be improved. As the epoxy compound to be used, JP-A-9-206885 (paragraph 0013)
To 0018).

As the water-soluble polymer (C), those having the properties described in “Beppu Kagaku Kogyo 25-14 Supplement, Water-Soluble Polymer” (Chemical Co., Ltd., December 1, 1981) Cellulose derivative-based water-soluble polymers as cellulose derivatives, further carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, protein-based water-soluble polymers as casein, sodium caseinate, ammonium caseinate, gelatin, Polysaccharide-based water-soluble polymers include starch, dialdehyde starch, agar, dextrin,
Dextran, pullulan, sodium alginate, glucomannan, galactomannan, gum arabic, xanthan gum, as polyvinyl-based water-soluble polymers, polyvinyl alcohol, polyvinylpyrrolidone, polyvinylbenzyl alcohol copolymer, as polyacrylic acid-based water-soluble polymer Is preferably a sodium polyacrylate or a polyacrylic acid (meth) acrylate copolymer, and the polyurethane-based water-soluble polymer is preferably a polyether polyurethane. More preferably, it is at least one selected from a cellulose derivative-based water-soluble polymer and a polyvinyl-based water-soluble polymer, more preferably at least one selected from hydroxyethyl cellulose and polyvinylpyrrolidone, and particularly preferably polyvinylpyrrolidone. is there.

These water-soluble polymers (C) are preferably used in an amount of 0.1 to 5 parts by weight, more preferably 0.3 to 3.0 parts by weight, per 100 parts by weight of the aggregate (A). When the amount is 0.1 part by weight or more, the stacking property is good, and when it is 5 parts by weight or less, the flowability of the kneaded sand is good and the cutting property is also good.

Further, a surfactant may be used in combination with the composition of the present invention in order to improve the cutting performance of the kneading sand. As the surfactant, a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a silicone surfactant, a fluorine-based surfactant, and the like can be used, and are not particularly limited. . The amount of the surfactant is 0.0% with respect to 100 parts by weight of the aggregate (A).
005 to 0.01 parts by weight is preferred.

The kneading sand (kneaded material of sand and binder) used in the shaping molding method is required to have a stacking property and a cutting property. Stackability refers to the property that the lower sand does not collapse due to the weight of the upper sand when the sand is piled up in the flask, and particularly affects the moldability on the inclined surface where the molding surface is vertical or close to it . On the other hand, the cutting property refers to a property that when sand is sanded with a shaving board, the sand surface can be finished smoothly without the sand adhering to the formed edge of the shaving board. In the present invention, in order to quantitatively evaluate the moldability (stackability and cutability) of the composition for shaping mold making, the following “moldability%” is used.
Is used.

<Measuring method of moldability%> One end is 10 m in height
50mm inside diameter, height 3 sealed with m piston head
A kneading sand to be evaluated is filled in a 00 mm PVC cylinder, and is extruded upward from a top opening by a piston.
The weight (A) of the extruded sand column without losing its shape was measured, and the ratio to the weight (B) of the filled kneaded sand [(A
/ B) × 100]. In the case of kneaded sand having poor stackability, the extruded sand column collapses due to its own weight, so that the formability% becomes small. On the other hand, in the case of kneaded sand having poor cutting performance, when extruded from the cylinder, the outer peripheral surface of the sand column is peeled off at the opening edge of the cylinder, so that the sand column is broken and the formability% is reduced. Therefore, the moldability determined by the stackability and the cutting ability can be quantitatively evaluated by measuring the moldability%.

[0020]

Examples 1 to 23 Organic ester-curable alkali resole resin [Kaohsstep S-66]
2 (manufactured by Kao Quaker Co., Ltd., described as B-1 in Table 1) shown in Table 1 and an organic ester curing agent [Kaostep KC-150 (manufactured by Kao Quaker Co., Ltd.)] in an aqueous alkaline resole resin solution 20% by weight based on the weight of the water-soluble polymer (C) shown in Table 1 and the same amount of water as the water-soluble polymer, and a curing agent, water, a water-soluble polymer, The alkali resole resin aqueous solution was mixed in this order and kneaded for 2 minutes.

A test piece having a moldability of 50 mm and a height of 50 mm was separately formed by the method described above,
It was left in an environment of 5 ° C. and a humidity of 60% RH, and the compressive strength after 24 hours was measured. Table 1 shows the results.

Examples 24 to 27 Carbon dioxide-cured alkali resole resin [Kao Step C-800 (manufactured by Kao Quaker Co., Ltd., indicated as B-2 in Table 1)] was added to 100 parts by weight of Kaketsufusen No. 5 sand. .
5 parts by weight, organic ester curing agent [Kao Step KC-
150 (manufactured by Kao Quaker), 0.2 parts by weight of an epoxy compound (Denacol EX-313), 0.5 parts by weight of the water-soluble polymer shown in Table 1, and water solubility To the same amount of water as the polymer, and in Example 26, 0.005 part by weight of a nonionic surfactant [Emulgen 709 (manufactured by Kao Corporation)] was added, and a curing agent and water (Example 26 Further, a surfactant), a water-soluble polymer, and an aqueous alkali resol resin solution were mixed in this order and kneaded for 2 minutes. Thereafter, a test piece was formed in the same manner as in Examples 1 to 23.
The compressive strength was measured. For Example 27, after kneading, the compressive strength after blowing 5 parts by weight of carbon dioxide gas with respect to 100 parts by weight of the aggregate was measured. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 An organic ester-curable alkali resole resin [Kao Step S-66] was added to 100 parts by weight of Kaketsufusen No. 5 sand.
2 (manufactured by Kao Quaker Co., Ltd.)] and 0.7 parts by weight of an organic ester curing agent [Kaostep KC-150 (manufactured by Kao Quaker Co., Ltd.)], and kneaded for 2 minutes. Test pieces were molded and the compressive strength was measured in the same manner as in Examples 1 to 23. The results are shown in Table 1.

Comparative Example 2 2.5 parts by weight of a carbon dioxide-cured alkali resole resin (Kao Step C-800 (manufactured by Kao Quaker Co., Ltd.)) and 100 parts by weight of an organic ester curing agent [Kaoh 0.5 parts by weight of Step KC-150 (manufactured by Kao Quaker Co., Ltd.) was mixed, kneaded for 2 minutes, and a test piece was molded in the same manner as in Examples 1 to 23, and the compressive strength was measured. Shown in

Comparative Example 3 Water glass (2 parts) was added to 100 parts by weight of
No. 5 parts by weight and 1 part by weight of dical (2CaO.SiO ₂ ) were blended and kneaded for 2 minutes, and a test piece was molded in the same manner as in Examples 1 to 23, and the compressive strength was measured. Table 1 shows the results.

Comparative Example 4 An organic ester-curable alkali resole resin [Kaohsstep S-66] was added to 100 parts by weight of Katsufusen No. 5 sand.
2 (manufactured by Kao Quaker Co., Ltd.)], 0.7 parts by weight of an organic ester hardener [Kaostep KC-150 (manufactured by Kao Quaker Co., Ltd.)], bentonite [Kunigel VA (Kunimine Kogyo Co., Ltd.) 2.2 parts by weight)
1.32 parts by weight of water was mixed and kneaded for 2 minutes.
A test piece was formed in the same manner as in No. 23, and the compressive strength was measured. Table 1 shows the results.

[0027]

[Table 1]

The parts by weight in Table 1 are for the aggregate (Kaketsufusen 5).
No. sand) 100 parts by weight.

[0029]

According to the present invention, it is possible to make a shaving mold with an organic binder having good kneading sand moldability and compressive strength as compared with the conventional shaping mold making method.

Claims (4)

[Claims] 1. An aqueous solution of at least one selected from an aggregate (A), an alkaline resole type phenol resin (B), a cellulose derivative, a protein, a polysaccharide, a polyvinyl, a polyacrylic acid and a polyurethane. A composition for shaping mold comprising a conductive polymer (C). 2. The water-soluble polymer (C) is used as an aggregate (A) 100.
The composition according to claim 1, which is contained in an amount of 0.1 to 5 parts by weight based on part by weight. 3. The composition according to claim 1, wherein the water-soluble polymer (C) is at least one selected from cellulose derivative polymers and polyvinylpyrrolidone. 4. The composition according to claim 1, further comprising 0.5 to 10 parts by weight of the alkali resol type phenol resin (B) based on 100 parts by weight of the aggregate.