Moulding sand binder and preparation method thereof
Technical field
The present invention relates to the Modeling Material of sand casting, be specifically related to moulding sand binder.In addition, the invention still further relates to the preparation method of this moulding sand binder.
Background technology
At present, casting mould material mainly contains resin self-setting sand and self-setting silicate process from hard technology.
Resin self-setting sand can be divided into three kinds of sour self-hardening resin sand, urethane self-hardening resin sand and phenolic resin self-hardening resin sands, its main binding agent is furane resins, phenolic resins, phenolic resin etc., as catalyst and additive, make molding sand hardened forming voluntarily in core box or sandbox with p-methyl benzenesulfonic acid, benzene sulfonic acid, triethanolamine, isocyanates, methyl formate, glycerine two alcohol acetates etc.Though the resin self-setting sand setting rate is fast, intensity is high, casting dimension accuracy is high, there is lack of raw materials and the gradually high situation of environmental requirement for worldwide organic resin, and the use of the resin self-setting sand of high volatile volatile organic matter (VOC) content will be restricted.
Self-setting silicate process be with waterglass as binding agent, add the molding sand that curing agents such as slag, acid anhydrides, prodan, ferrosilicon powder, organic ester and carbonic ester make it to harden voluntarily.Waterglass does not have the shortcoming of organic resin as inorganic binder, and a difficult problem is perplexing casting field always but sodium silicate sand collapsibility is poor, old sand reuse difficulty, intensity are lower etc.And existing in the market composite modified water-glass sand, though make these situations obtain improvement to a certain degree, but, make water-glass sand have the defective of some resin sand because it has added the water miscible organic matters such as phenol, formaldehyde, urea, quaternary amine that contain; Its preparation method is loaded down with trivial details in addition, needs to use special chemical reaction device, and the pressure process of heating control is complicated.
Summary of the invention
The objective of the invention is to overcome the above-mentioned deficiency of prior art, a kind of free-phenol, formaldehyde of not containing is provided, not phosphorous, nitrogen, sulphur, safety non-toxic, molding sand process function admirable, and the moulding sand binder that preparation procedure is simple, old sand can reuse.
Another object of the present invention provides the preparation method of above-mentioned moulding sand binder.
In order to realize the foregoing invention purpose, moulding sand binder of the present invention, form by the component of following weight percentage:
Concentration is the peo resin aqueous solution 5-35% of 0.1-2.0%;
Waterglass 50-90%;
Additive 4-18%;
Water 0-10%;
The structural formula of described peo resin is (CH
2CH
2O-)
n, molecular weight 1.0 * 10
5-6.0 * 10
6
Described additive is the mixture of borax and sugar alcohol, wherein, and borax: sugar alcohol=1: 2-10 (weight ratio).
In addition, among the present invention, above-mentioned sugar alcohol preferably is selected from sorbierite, maltitol or sweet mellow wine.
The preparation of above-mentioned moulding sand binder of the present invention comprises the following steps:
(1) with extremely even in the peo resin aqueous solution in the additive adding stirring;
(2) mixed liquor that step (1) is made adds in the waterglass, stirs.
Among the preparation method of moulding sand binder of the present invention, perhaps before water is added in the additive earlier in step (1) and stir, carry out (1), (2) more set by step.
Among the preparation method of moulding sand binder of the present invention, perhaps afterwards water is added in the mixed liquor of the additive and the peo resin aqueous solution in step (1), carry out (2) more set by step.
With respect to the moulding sand binder of prior art, the present invention uses organic binder bond (peo resin) and inorganic binder (waterglass) combination, has overcome the shortcoming of independent use organic binder bond and inorganic binder.Because the peo resin that uses is a kind of heavy polymer, its solution has very high viscosity under low concentration, sand grains there is fabulous wetting action, therefore can make sand grains coat last layer homogeneous film at short notice, help molding sand with the additive interaction and form higher intensity.Peo resin decomposes totally about 600 ℃, the deformability and the performance of shaking out of the more common self-setting silicate process of molding sand of binding agent of the present invention are greatly improved, and foundry goods is not easy to crack, and cleaning is convenient.The selected peo resin of the present invention is through biologic test, its oral toxicity is very low, can be used safely in industries such as food, medicine, the glycitols product also is widely used in food, medicine, toothpaste, cosmetic industry, and the other materials in the binding agent is inorganic matter, the penetrating odor that therefore relative resin self-setting sand is in use given out, binding agent of the present invention do not have smell tasteless, as the binding agent of casting mould material, be minimum to the influence of environment.
In addition, the preparation method of moulding sand binder provided by the invention does not need special-purpose chemical industry reaction unit, the requirement that heats up and pressurize only need general general mixer to make, so the preparation technology of this binding agent is simple, be easy to control, and the input of equipment is also less.
The specific embodiment
Below in conjunction with embodiment the present invention is further described.
Embodiment 1
(borax: sorbierite=1: 7) slowly adding with the 50g concentration in GFJ-0.4 type high speed dispersor (manufacturing of the Shanghai coatings industry machinery plant) stirring is in 0.7% the peo resin aqueous solution with the 50g additive, again above-mentioned mixed liquor is added in the 900g waterglass and stir, make binding agent 1000g.
Embodiment 2
At first 50g water is added 50g additive (borax: stir with GFJ-0.4 type high speed dispersor (manufacturing of Shanghai coatings industry machinery plant) sorbierite=1: 3), while stirring it is slowly added 100g concentration then and be in 1.8% the peo resin aqueous solution, again mixed liquor is added in the 800g waterglass and stir, make binding agent 1000g.
Embodiment 3
At first (borax: maltitol=1: 5) slowly adding with the 220g concentration in GFJ-0.4 type high speed dispersor (manufacturing of the Shanghai coatings industry machinery plant) stirring is in 1.0% the peo resin aqueous solution with the 90g additive, then 40g water is added and wherein stir evenly, again mixed liquor is added in the 650g waterglass and stir, make binding agent 1000g.
Embodiment 4
(borax: sweet mellow wine=1: 10) slowly adding with the 330g concentration in GFJ-0.4 type high speed dispersor (manufacturing of the Shanghai coatings industry machinery plant) stirring is in 0.3% the peo resin aqueous solution with the 170g additive, again above-mentioned mixed liquor is added in the 500g waterglass and stir, make binding agent 1000g.
Embodiment 5
Weighing 2000g calibrating casting binder places NRJ-411A type cement mortar mixer (manufacturing of Wuxi construction material instrument machinery plant) with normal sand, adding curing agent glycol acetate (Xinghua plant produced is closed in Yixing) mixed 40 seconds, adding the binding agent that embodiment 1 makes again mixed 40 seconds, shake out, press GB2684-81 " casting roughing sand and test mixture method " and make Φ 50 * 50 cylindrical standard specimens, measure the compression strength of placing different time with SWY hydraulic pressure strength testing machine and SWY-FH high strength t.a (manufacturing of Wuxi City three peak instrument and equipment Co., Ltds), the results are shown in Table 1.
Table 1
(25.5 ℃ of temperature, relative humidity 70%)
Embodiment | Binding agent addition (g) | Curing agent addition (g) | Compression strength MPa |
??0.5h | ??1h | ??2h | ??4h | ??24h |
????1 | ????44 | ????4.4 | ??0.55 | ??0.97 | ??1.17 | ??1.90 | ??3.30 |
????1 | ????50 | ????5.0 | ??0.75 | ??1.08 | ??1.45 | ??2.30 | ??4.00 |
????1 | ????56 | ????5.6 | ??0.78 | ??1.10 | ??1.70 | ??2.30 | ??4.10 |
Embodiment 6
Weighing 2000g Fujian sand (70/140 order) places NRJ-411A type cement mortar mixer (manufacturing of Wuxi construction material instrument machinery plant), adding curing agent glycol acetate (Xinghua plant produced is closed in Yixing) mixed 40 seconds, add embodiment 1 more respectively, the binding agent that embodiment 2 and embodiment 3 make mixed 40 seconds, shake out, press GB2684-81 " casting roughing sand and test mixture method " and make Φ 50 * 50 cylindrical standard specimens, measure the compression strength of placing different time with SWY hydraulic pressure strength testing machine and SWY-FH high strength t.a (manufacturing of Wuxi City three peak instrument and equipment Co., Ltds), the results are shown in Table 2.
Table 2
(22.5 ℃ of temperature, relative humidity 50%)
Embodiment | Binding agent addition (g) | Curing agent addition (g) | Compression strength MPa |
??0.5h | ??1h | ??2h | ??4h | ??24h |
????2 | ????50 | ????5.0 | ??0.40 | ??1.00 | ??1.30 | ??2.20 | ??3.60 |
????3 | ????50 | ????5.0 | ??0.38 | ??0.90 | ??1.20 | ??1.93 | ??3.00 |
????4 | ????50 | ????5.0 | ??0.35 | ??0.92 | ??1.20 | ??1.80 | ??3.20 |
Embodiment 7
Weighing 2000g calibrating casting binder places NRJ-411A type cement mortar mixer (manufacturing of Wuxi construction material instrument machinery plant) with normal sand, adding curing agent glycol acetate (Xinghua plant produced is closed in Yixing) 5.0g mixed 40 seconds, adding the binding agent 50g that embodiment 1 makes again mixed 40 seconds, shake out, press GB2684-81 " casting roughing sand and test mixture method " and make Φ 50 * 50 cylindrical standard specimens; Weighing 2000g calibrating casting binder places NRJ-411A type cement mortar mixer (manufacturing of Wuxi construction material instrument machinery plant) with normal sand in addition, adding curing agent glycol acetate (Xinghua plant produced is closed in Yixing) 8.0g mixed 40 seconds, adding waterglass (production of Shanghai Shen Bao oil chemistry factory) 80g again mixed 40 seconds, shake out, press GB2684-81 " casting roughing sand and test mixture method " and make Φ 50 * 50 cylindrical standard specimens; The sample that makes was placed after 24 hours, be placed in the SX-10-12 chamber type electric resistance furnace (manufacturing of Shanghai experimental electric furnace factory) of different temperatures insulation 30 minutes, taking-up is chilled to room temperature, measure its residual compression strength respectively with SWY hydraulic pressure strength testing machine (manufacturing of Wuxi City three peak instrument and equipment Co., Ltds), the results are shown in Table 3.
Table 3
(25.5 ℃ of temperature, relative humidity 80%)
Binding agent | Residual compression strength MPa |
??200℃ | ??400℃ | ??600℃ | ??800℃ | ??1000℃ |
Embodiment 1 | ??3.20 | ??0.80 | ??0.38 | ??0.34 | ??0.68 |
Waterglass | ??3.27 | ??0.89 | ??0.65 | ??0.89 | ??1.12 |