| JPH07204776 | SOLIDIFYING METHOD OF SAND |
PETERSSON L (SE)
AHLANDSBERG I (SE)
PETERSSON L (SE)
| SE319582B | 1970-01-19 | |||
| US3424600A | 1969-01-28 | |||
| GB1366705A | 1974-09-11 |
| 1. | (received by the International Bureau on 16 June 1980 (16.06.80)) A method of manufacturing a foundry core or mould of granular and/or fibrous material with sodium silicate or potassium silicate as binding agent, c h a r a c t e r¬ i z e d in. that the sodium or potassium silicate is added to the mixture of the material in an amount of 1 to 5% calculated on the weight amount of material, that a ≤urface active substance is added in an amount not exceeding 0,11 calculated on the weight amount of material, and that the core or mould are heated to between 110 C and 180 C. |
| 2. | A method as defined in claim 1, c h a r a c t e r¬ i z e d in that' the surfaceactive substance is a tenside, silicone oil, silicone emulsion or siliconate, preferably silicone emulsion. |
| 3. | A method as defined in any one of the claims 12, c h a r a c t e r i z e d in that a core box is used which is heated to 110180°C. |
| 4. | A method as defined in any one of the claims 15, c h a r a c t e r i z e d in that the core is blown through with hot air of a temperature of 110180 C. |
| 5. | A method as defined in any one of the claims 13, c h a r a c t e r i z e d in that the core is blown through with CO with or without supplementary throughblowing of hot air. |
| 6. | A method as defined in any one of the claims 35, c h a r a c t e r i z e d in that the core or mould is formed of core and, respectively, mould mass, to which an ester hardener was added. |
| 7. | A method as defined in any one of the preceding claims, c h a r a c t e r i z e d in that the sodium or potassium silicate has a molar ratio of between 2 and 3. |
| 8. | and 9 (cancelled) OMH What we claim is: 1 A method' of manufacturing a foundry core or mould of granular and/or fibrous material with sodium silicate or potassium silicate as binding agent, c h a r a c t e r ±τ e~"d" "in trha surfaceactive substance is added at the mixing of the material, and that the core or mould are heated to between 110°C and 180°C. |
| 9. | 2 A method as defined in claim 1, c h a r a c t e r¬ i z e d in that the sodium or potassium silicate is added to the mixture of the material in an amount of 1 to 3 _ calculated on the weight amount of material. |
| 10. | 3 A method as defined in claim 1 or 2, c h a r a c t e r i z e d in that the surfaceactive sub¬ stance is a tenside, silicone oil, "silicone emulsion or siliconate. |
| 11. | 4 A method as defined in any on of the claims 13,. c h a r a c t e r i z e d in that the surfaceactive sub¬ stance is added in an amount not exceeding 0,1 % calcul¬ ated on the weight amount of material. |
| 12. | 5 A method as defined in any one of the claims 14, c h a r a c t e r i z e d in that a core box is used which is heated to 110180°C. |
| 13. | 6 A method as defined in any one of the claims 15, c h a r a c t e r i z e d in that the core is blown through with hot air of a temperature of 110180 C. |
| 14. | 7 A method as defined in any one of the claims 15, c h a r a c t e r i z e d in that the core is blown through with C02 with or without supplementary through blowing of hot air. |
| 15. | 8 A method as defined in any one of the claims 57, c h a r a c t e r i z e d in that the core or mould is formed of core and, respectively, 'moμld mass, to which an ester hardener was added. |
| 16. | 9 A method as defined in any one of the preceding claims, c h a r a c t e r i z e d in that the sodium or potassium silicate has a molar ratio of between 2 and 3. |
INTERNAΗONAL APPLICAΗON PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
(51) International Patent Classification -: (11) International Publication Number: WO 80/01254
Al B22C 1/16, 9/12; C04B 19/04 (43) International Publication Date: 26 June 1980 (26.06.80)
(21) International Application Numbeπ PCT/SE79/00257 (74) Agents: AB STOCKHOLMS PATENTBYRA, ZACCO & BRUHN et al.; Box 3129, S-10362 Stockholm (SE).
(22) International Filing Date: 21 December 1979 (21.12.79)
(81) Designated States: DE, GB, JP, SU, US.
(31) Priority Application Numbers: 7813194-3 7907450-6
Published
(32) Priority Dates: 21 December 1978 (21.12.78) With international search report 7 September 1979 (07.09.79)
Publishedbefore the expiration of the time limitfor amending
(33) Priority Country: SE the claims and to be republished in the event of the receipt of amendments.
(71) Applicant (for all designated States except US): AHL-
SELL IR AB [SE/SE]; 27 Hammarbyvagen, S-10460 Stockholm (SE).
(72) Inventors; and
(75) Inventors/Applicants (for US only): AHLANDSBERG, Ingemar [SE/SE]; 17 Dalgangen, S-139 00 Varmdό (SE). PETERSSON, Lars-Erik [SE/SE]; 41 Bergviks- gatan, S-151 50 Sodertalje (SE).
(54) Title: A METHOD OF MANUFACTURING A FOUNDRY CORE OR MOULD OF GRANULAR AND/OR FI¬ BROUS MATERIAL
(57) Abstract
Method of manufacturing a foundry core or mould bound with alkah silicate. A surface-active substance is adde at the mixing of the mould material, and the mould or core are heated moderately, i.e. to a temperature of between 1 lOoC and 180OC.
FOR THE PURPOSES OF INFORMATION ONLY
Codes used to identify States party to the PCT on the front pages of pamphlets publishing international appli- cations under the PCT.
AT Austria LI Liechtenstein
AU Australia LU Luxembourg
BR Brazil MC Monaco
CF Central African Republic MG Madagascar
CG Congo MW Malawi
CH Switzerland NL Netherlands
CM Cameroon NO Norway
DE Germany, Federal Republic of RO Romania
DK Denmark SE Sweden
BR France SN Senegal
GA Gabon su Soviet Union
GB United Kingdom TD Chad
HU Hungary TG Togo
JP Japan US United States of America
KP Democratic People's Republic of Korea
A method of manufacturing a foundry core o.r mould of granular and/or fibrous material
This invention relates to a method of manufacturing a foundry core or mould of granular and/or fibrous material with sodium silicate or " potassium silicate as binding agent- Sodium or potassium silicate, hereinafter called alkali silicate, has been used for a long time at the manufacture of moulds and cores of, for example, sand in the foundry industry. The moulds and cores are quenched at room temperature by means of admixed hardeners or by blow¬ ing through with CO-. Such a manufacture, 'however, requires a relatively..high binding agent content for achieving sufficient strength. Besides, the use of alkali silicate as binding agent involves several other disadvantages, of ' which .particularly the following ones may be mentioned:
Reduction of refractoriness of moulds and cores. Poor disintegration of moulds and cores after casting. Low recovery percentage of used core and mould mate¬ rial (moulding sand).
These disadvantages have heretofore limited the utilization of the alkali silikate at the manufacture of moulds or cores.
At the manufacture of cores with organic binding agents, usually resins, a material (for example some acid) is admixed to act as hardener and also the core boxes or cores are heated to a temperature between 250°C and 300°C. Cores manufactured in this way give rise to a sub¬ stantial gas development both at the core manufacture and during the subsequent casting, thereby rendering the environment in such a foundry unfriendly. Moreover, such a core manufacture requires relatively much energy. The present invention has the object to reduce the aforesaid disadvantages and relates to a method of manu¬ facturing a foundry core or mould of granular and/or fibrous material with. sodium silicate or potassium
silicate as binding agent. The invention is substantially characterized in that a surface-active substance is added at the mixing of the material, and that the core or mould is heated to between 110°C and 180°C. By adding according to " the invention a sur ace-active substance to the mould material and by heating the core or mould to between 110°C and 180°C, it is possible to reduce the added amount of alkali silicate, compared with the amount conventionally used, without thereby decreasing the strength and surface hardness of the mould or core. This implies, that the moulds and cores still can be handled and stored without difficulty, and that the moulds and cores also show satisfactory resistance to heat and mechanic stresses during the casting. Due to the low alkali silicate content, the disintegration after the casting is very good. The casting, besides, is protective to the environment, because gases detrimental to health are produced only to a small extent. The radiation heat at the core manufacture is moderate, and the nergy con- sumption is low. Owing to its rapid procedure, the method renders possible series production above all of cores. To the mould or core material to be bound, liquid alkali silicate, ratio (molar ratio) SiO 2 /N_uO-0.5-3.5, in- a relatively small amount and a surface-active sub- stance in the form of a tenside, a silicone oil, sili¬ cone emulsion or siliconate are added.
In order to be able to keep the binding agent amount at minimum and to achieve optimum disintegration after the casting, for example a sodium silicate with certain additives is used, which latter are: a) Surface-active substances such as tensides, silicones (oils, emulsions) or siliconates (for example Berol 305 . Rhodorsil E5S^ and, respectively, Tegosivin . b) Disintegration agents and surface-hardness form- ing agents in the " form of sugar derivatives, which usually are treated so as to maintain stable in sodium silicate solution.
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The invention is described in greater detail in the following by way of examples of the application, of the invention. It is to be observed that the heretofore usual amount of alkali silicate, calculated on the sand amount, is 3-5 % and more.
1) A mixture of sand and 1,5 % sodium silicate (ratio 2,7) calculated on the sand amount and 0,015 % silicone emulsion (35 %) was prepared. Of this mixture cylindric test bodies with the height 50 mm and the dia- meter 50 mm were manufactured. The test bodies were quenched at 150 C and pressure tested after cooling. Co -
2 pressive strengths of 500-600 N/cm were obtained. A zero test without silicone addition yielded compressive strengths o.f only 80-90 N/cm . At a sodium silicate content of 2 _ and 0,02 % sili-
2 cone emulsion compressive strengths of about 800 N/cm
2 were obtained while the zero test yielded about 550 N/cm .
2) A core box was heated to 150°C in a core shooter in a foundry for car material. A core mix was prepared of sand (mean grain size 0,25 mm) and 2,5 _ of a binding agent according to above. The core mix was filled into -.the machine -and. the core- was, shot, with such a pressure that a good packing degree was obtained, normally 400-700
2 kPa (4-7 kg/cm ). The cores heathardened in the box for 20-60 seconds depending on the thickness (10-50 mm) whereafter they were ready for casting.
3) Core manufacture was carried " out according to above. The cores, however, now were thicker and, there¬ fore, also hot air (110-150°C) was blown through the core box. It was possible in this way to manufacture fully satisfactory cores within t ss'than 0""seconds.
4) The core manufacture was carried out according to 3). The hot air, however, was here replaced by C0 2 ~gas. Also in .this way fully satisfactory cores could be manufactured. Heretofore this was not possible at the alkali silicate contents described above.
5) The core manufacture was carried out ' according
to 3), but a part of,the hot air was replaced by CO-- Fully satisfactory cores were obtained.
6) The core manufacture was carried out according to 4). Here, however, the binding agent was 3 _ (by weight) pure sodium silicate 49°Be, ratio 2.7, and 1 . of a sugar derivative, i.e. the total binding agent amount was 4 .. The cores showed good surface hardness. The disintegration after casting, however, is somewhat worse than for 2), 3) and 4) according to above. 7) The core manufacture was carried out according td 3), but with the addition of 7-10 . of an ester hard¬ ener of usual type. Hereby the core was dried through more rapidly, which ' is of value at the manufacture of large moulds/cores. It was found by experiments that the content of the surface-active substance should not exceed 0,1 calcul¬ ated on the amount of weight of material, and prefer¬ ably it should lie within the range 0,0001-0,1 % .