JPS5978746A - Resin-coated sand grain for shell mold - Google Patents

Abstract

PURPOSE:To develop molding sand for a shell mold having excellent ordinary temp. strength and collapsing property after casting by coating the surface of the molding sand for the shell mold for casting an Al alloy with a specific binder. CONSTITUTION:The surface of molding sand, such as silica sand or olivine sand, is coated with a binder having the following compsn., whereby molding sand for a shell mold is obtd. The binder prepd. by mixing 0.5-10pts.wt. carbonate of bivalent metal such as CaCO3 coated with a satd. fatty acid with 100pts.wt. a resol type phenolic resin or novolak type phenolic resin contg. halogenated phenolic resin or a halogenated compd. such as a halogenated arom. compd. or halogenated aliphat. compd. is used. The binder is mixed at 2pts.wt. in terms of the phenolic resin in 100pts.wt. a casting to coat the surface. The shell mold made of such molding sand has high ordinary temp. strength and has an excellent collapsing property after casting of an Al alloy.

Description

[Detailed description of the invention]

The present invention relates to I64 fat-coated sand grains for shell and flattening,
In particular, it relates to resin-coated sand grains (hereinafter referred to as I'l'< CS J) that are excellent in disintegration 111 after 6] [Include 1). Conventionally, RCS, which is a multi-no-one molding material, is known in which the surface of patterned sand is coated with a thermosetting resin such as 71-Nol resin. Such RcS is manufactured using methods such as Hora 1-Pro Wrestling, Remi Hot Pro-Wrestling, and 1-Rudobu, and has excellent regular 1-product strength and hot strength.However, Conventional RCS has the problem of poor lr + l breakdown after casting. This (yo, r< c s bond 4A (
゛A certain thermosetting 1!1 resin is aluminum Hl: r
:, it is not thermally decomposed sufficiently at low temperatures of about r, and the residual strength is high/ζ. For this reason, conventionally, after casting, it was necessary to heat the molded material to about 500°C for several tens of seconds and collapse it, a process called "sand baking".
The present invention has been devised in view of the above circumstances, and has been devised to reduce the loss of energy and time. The purpose is to offer 17 CS. The present invention is an RC8 consisting of foundry sand, etc., and a binding material coated on the surface of the foundry sand, and the binding material is halogenated film J.
It contains a phenol resin containing a phenol resin or a divalent compound, and a carbonate of divalent gold 11. Foundry sand is the living body of RC3, which is a mold making monthly rate. Molding sand is fluid 1 before molding! ■It is required to be rich in
is required. As foundry sand, silica sand, olipin sand, chromium 1~lead, zirconleand, fused silica grains, alumina grains, etc. are suitable, and the grain size of these is 70μ~i.
A value of about oooμ is good. The binding material has the function of binding the foundry sand to each other and molding it into a predetermined mold shape, and is made of a divalent metal-containing fuconol resin or a phenolic resin containing a compound containing a halogen element. Consisting of carbonate. The binding material includes
Metal oxides such as zinc oxide, iron oxide, manganese oxide, titanium oxide, etc. are used to promote thermal decomposition of the phenolic resin by the halogenated compound and to accelerate curing of the phenolic resin before molding. 1.5 to 15. OWI
It may be added about %. Tubonol resin (functions as a binder for the foundry sand). Phenol resin ff1. f, conventional R
As with CS, about 2 parts of small radius per 100 parts by weight of foundry sand is sufficient. ) As the 1-nol resin, Tadoepo, resol type Fu-J, norl resin, and novolac type 71-nol resin are suitable. The foundry sand may be coated with the 71-nol resin by any of the Hola 1 process, Shimi hot process, and cold process. The compound containing a halogen element serves as a combustion improver for the phenol resin and promotes thermal decomposition of the phenol resin. The halogen may be incorporated into the phenolic resin in the form of a halogenated phenol. For white-containing compounds containing halogen elements, ), rNol resin 100
Appropriately, about 1 part by weight is 1 part to 20 parts by weight. The compound containing a halogen element may be added to the 71Nol resin when manufacturing RCS by kneading the foundry sand and the phenol resin. A compound containing an element may be added.
is Te1-lachlorbisphenol△, atlab [! (mubisphenol Δ, brominated) ■ Halogenated aromatic compounds such as nilme, taacrylic acid ester, and phenyl allyl earth-nol, chlorinated baratuin, chlorinated polyJ
- Genated hydrocarbon compounds such as tyrene and chlorinated polypropylene can be used. The divalent metal carbonate traps the halogen element generated during thermal decomposition of the compound containing the halogen element, prevents corrosion of molds, etc., and prevents deterioration of the working environment.
It has a function of thermally decomposing the phenolic resin contained in the compound containing the halogen element. 21+
As the carbonate of the 11i metal, calcium carbonate, magnesium carbonate, barium carbonate, zinc carbonate, etc. can be used. When calcium carbonate is used, its addition 171
- The effect of the invention is even more effective when the amount of calcium carbonate is about 0.5 to 10 inffft parts per 100 parts of norol resin. J: The carbonate of the 21111i metal is preferably coated with the L protective solution 119.The reason for this is that the carbonate of the 21111i metal and the carbonate of the 2ilTli metal are This is to prevent the film from reacting with the phenol resin.Therefore, the lap 'f (H size of the film is
It is possible to prevent the reaction between the carbonate of a valent metal +3,1 and the [I-nor resin], and at high temperatures, the carbonate of a divalent metal and the above-mentioned haf
"J, yes, as long as it does not interfere with the reaction with hydrogen genide. 1! If the irises are present, the humidity is high enough to harden the phenolic resin. -4", the carbonate of the divalent metal is added to protect it, and the phenol resin absorbs heat FJ?^^
The divalent metal is evaporated by drying and brought into contact with the phenolic resin.1. Good monthly interest. Such a stable pattern can be obtained, for example, by surface treating calcium carbonate with a saturated fatty acid. The R(:, S) of the present invention having the above-mentioned structure has excellent disintegration properties after casting. On the other hand, when the hydrogen halide generated from the compound containing the hydrogen element is wrapped by the carbonate of the divalent metal, the thermal decomposition and combustion are further accelerated. This is because the rows can be executed more quickly. In particular, the RCS of the present invention has excellent disintegration properties when cast at a low molten temperature of aluminum, and does not require sand baking. Therefore, there is no loss of energy or time. J. The strength of the RC8 of the present invention after molding is comparable to that of the conventional RC8. This is because bonding (J to the phenolic resin A ensures room temperature strength 1. hot strength. Hereinafter, an example of the present invention will be described. Using silica sand as pot sand,) As a J-nor resin,
RC3 of the present invention was produced using a nearresol resin, a chlorinated paraffin as a compound containing the element Ha, and lucium carbonate as a divalent metal carbonate. Two scales of the RCS were prepared by changing the amount of calcium carbonate added as shown in the table, and used as Examples 1 and 2, respectively. Also, for comparison, RC8 without adding calcium carbonate
was manufactured and used as a comparative example. Specifically, it was manufactured in the order of (A), (B), and (C) above. 1. Pour ε35% rose formaldehyde 282k () into a reaction vessel and cool it.
1. , while gradually adding 25% ammonia water (751g) until the reaction liquid temperature does not exceed 555℃. (2) Keep the reaction liquid temperature at 55□-60℃ and adjust the viscosity (3) Condense 1112 water under reduced pressure of 110 = -1501'orr. (4) As soon as the temperature of the reaction solution reaches 70°C, heat and reduce pressure. Pour 100 kg of methanol and dissolve. (5) Pour 50 kO of chlorinated paraffin as a compound containing redundant carbon at 50'C and dissolve. (6) This methanol solution of ammonia aresol was spray-dried with a spray dryer, and one solid ammonia aresol resin with an average spherical diameter of 500 μ was used as a nol resin.
! It's V. (The capped Iζ resin has an average molecular weight of 1550
, Flow! III (at 125°C) '111 nv, gel time (at 150°C>92secr). )(
B) Mixing of Calcium Carbonate Calcium carbonate and the like were mixed in the following parts by weight with 1001 parts of the ammonia aresol resin containing 1M hydrogenated para-twin produced in the above (Δ). (Example 1) Fatty acid surface-treated lucium carbonate/1 weight x Y part and 1.5 mm part of zinc stearate were mixed and powdered. (Example 2) 8 parts by weight of fatty acid surface-treated calcium carbonate, 0.5 parts by weight of lead stearate 111j, and 1.5 parts by weight of dilene bisthurano'phosphate aphide were mixed (1). (Comparative example) Calcium carbonate was not added, and a 2-width hanging part of 1F sulphate was mixed and powdered. (C) Manufacture of RC8 8 kg of foundry sand preheated to 160°C was placed in a speed mixer NS (type 2 (manufactured by Enshuune T)).
When the temperature reached 50°C, add 160 g of each of the materials prepared in Examples 1 to 2 and Comparative Example (2) and knead for 30 seconds. Next, add 120 g of cold IAI water and knead further. 35 seconds. Add 8 g of calcium stearate, mix for 20 seconds, then discharge, and prepare the resin-coated sand grains for shell mold shown in the table (cl for qRC8). The actual results are shown in the table. Of the test methods used in the above test, the fusion point
A C1-Test method C-1, and room temperature bending strength is JIS
Each fj'tT was carried out according to K-6910. Warm bending strength GJ J A CT tiIt test method 5M-
5 and t (t). Also, the disintegration rate was calculated as follows:
Create a test piece with a length of 35.11J10 and a length of 40 mm, and wrap the 7-stroke piece twice with aluminum foil in advance to prevent contact between the test piece and the air.
Place in an electric furnace adjusted to ℃ for 20 minutes (
). After cooling to room temperature, use a 24-meter sieve
Vibrate for 3 minutes to disintegrate the test piece [!
A small amount of fallen sand is measured in the receiving space. Collapse rate = (weight of falling sand / Dest bead small skewer) x 100. Also, hydrogen chloride fleas are measured on gold plated at 300℃. RC8 in the mold
Drop 50CJ and 30 seconds later, the light will appear 11C1f
I decided to measure fl with the north type detector tube, so I did four steps. From the table, r
When 4 parts by weight or more of culm is added to 0 parts by weight, there is a noticeable C'. , consisting of foundry sand and a binder coated on the surface of the foundry sand, and the binder is made of halogenated phenolic resin or halide.

[-1 Contains a gunified compound-
It contains J-norm resin and bivalent carbonate, and is characterized by its excellent fracture resistance after casting and casting. Special 7f applicant Aisin Chemical Co., Ltd. 1 Agent
As a patent attorney, Anama Okawa As a patent attorney, Osamu Fujitani

Claims (3)

[Claims] (1) consisting of a binder coated on the surface of the foundry sand, the binder (i.e., halogenated), r-nol resin, or (c), phenol resin containing a 1-glycan compound; 1. Resin-coated sand grains for J-ru seal molds, characterized by containing carbonates of valuable metals. (2) The carbonate of the divalent metal is calcium carbonate coated with a protective layer, and the ratio of the carbonate and calcium to the phenol resin is 100 parts by weight of the 71-noyl resin. Calcium carbonate 0.5-10 for shell mold of claim 1 which is 0.5-10 heavy hanging part (h-
1 fat coated sand grain. (3) The above-mentioned compound is at least one selected from group J of group J of group J, group J of group J, group J of group J, group of group J, group of group J, group of group J, group of group J, group of group J, group The ratio of the compound to the phenolic resin is 1 to 20 parts by weight of the halogenated compound to 100 parts by weight of the 71-noryl resin. .