JB/T 7527-1994 Method for determination of properties of self-hardening furan resin for casting
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Self-hardening furan resin for casting
Methods for determination of properties
Subject content and scope of application
This standard specifies the technical properties and determination methods of furan resin synthesized with furfuryl alcohol as the main raw material. This standard applies to acid-hardened furan resin binders for casting. 2 Reference standards
GB265 Determination of kinematic viscosity and calculation of dynamic viscosity of petroleum products GB601 Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB2684
GB2794
GH 4472
Test methods for raw sand and mixtures for castingbzxz.net
Methods for determination of viscosity of adhesives (rotational viscometer method) General rules for determination of density and relative density of chemical products GB 12007. 5
ZB J31 006
3 Technical performance
4 Determination method
Determination method of epoxy resin density Pycnometer method Standard sand for casting binder
4.1 Determination method of viscosity
Viscosity (20'℃), mPa·s
Density (20℃), g/cm2
Formaldehyde content, %
Nitrogen content, %
JB/T7527
Tensile strength of casting process sample at room temperature (24h), MPa4.1.1 Flat capillary viscometer method: in accordance with GB265-arbitration method. 4.1.2 Rotational viscometer method: in accordance with GB2794. 4.2 Determination method of density
4.2.1 Pycnometer method: in accordance with GB12007.5-arbitration method. 4.2.2 Densitometer method: in accordance with GB4472. 4.3 Determination of free formaldehyde content
4.3.1 Principle: Free formaldehyde and ammonium fluoride, under the action of sodium hydroxide, quantitatively generate cyclohexamethylenetetramine. The free formaldehyde content can be calculated by using hydrochloric acid standard solution and excess sodium oxynitride. The reaction formula is as follows: 6HCHO+- 4NH,CI+4NaOH - (CH2).N +4NaCI +10H2ONaOH+HCI= NaCl-+ H,O
4.3.2 Instruments and equipment
Iodine volume flask: 250mL;
Burette: 50mL, graduation value 0.1mL;
Pipette: 25mL, 10mL, graduation value 0.1mLc.
Analytical balance: sensitivity 0.1mg;
Magnetic stirrer: 1 unit:
Acidity meter: 1 unit, graduation value 0.1pH.
Reagents and solutions: The preparation and calibration of standard solutions shall be carried out in accordance with the provisions of GB601. 4.3.3
Sodium hydroxide: analytical grade, 0.5 mol/L; Hydrochloric acid: analytical grade, 0.5 mol/L;
Ammonium chloride: analytical grade, 10% solution
Anhydrous ethanol: analytical grade;
Brominated blue indicator: 0.1% ethanol solution. 4.3.4 Determination procedure: Weigh 2.5~3.0g (accurate to 0.0002g) of resin sample by reduction method, place in 250mL iodine volumetric flask, add 25ml of anhydrous ethanol to dissolve the sample, then add 10ml of 10% ammonium chloride solution and 25ml of 0.5mol/L sodium hydroxide solution (note that the order of addition cannot be reversed), plug the bottle cap and add a small amount of distilled water, place at 20°C for 0.5h, add 1 drop of 0.1% bromothymol blue indicator, shake and titrate with 0.5mol/L hydrochloric acid standard solution, transfer the sample to a 250mL beaker when it is close to the end point, place it on a magnetic stirrer and use an acidometer to control the pH to 7, that is, the end point is reached. At the same time, do a blank test. Blank test: Except for not adding the sample, the same analytical steps, reagents and dosages (except the dosage of standard titration solution in titration) as the determination should be used, and parallel operation should be performed.
4.3.5 The free formaldehyde content3 (%) is calculated according to the formula (1): y
(V.-V)CX 0. 045 03
Wherein: V. Volume of standard hydrochloric acid titration solution consumed in the blank test, mL; V---the volume of standard hydrochloric acid titration solution consumed in the sample determination, ml, C the concentration of standard hydrochloric acid solution mol/L;
m.-sample mass+g;
0.04503--the mass of formaldehyde in grams equivalent to 1mL of standard hydrochloric acid titration solution. (1)
4.3.6 Take the average value of the parallel determination results as the determination result of the free formaldehyde content of the resin, and the relative deviation is allowed to be no more than 20%. 4.4 Determination method of nitrogen content
4.4.1 Principle: The nitrogen in the organic compound is converted into ammonia, and the distilled hydrogen is absorbed by boric acid solution, and the nitrogen content is determined by acid-base titration.
Instruments and equipment
General laboratory instruments,
Kjeldahl nitrogen flask: 500mL;
Condenser: 400mm straight tube condenser;
Conical flask: 500ml;
Burette: 50mL acid burette, graduation value 0.1mL. 4.4.3 Reagents and solutions: The preparation and calibration of standard solutions shall be carried out in accordance with the provisions of GB601. a.
Hydrochloric acid: analytical grade 0.05mol/L standard titration solution; 531
Thiophene: analytical grade;
Potassium persulfate: analytical grade;
Sodium hydroxide: analytical grade, 50% solution;
Boric acid: analytical grade, 4% solution;
JB/T 752794
Methyl red-auroin green mixed indicator: 20ml of 0.1% methyl red ethanol solution and 50ml of 0.1% cresol ethanol solution. Mix well.
4.4.4 Determination procedure: Weigh 0.1-0.8g of resin sample (accurate to 0.0002g) by reduction method, place in a 500ml Kjeldahl nitrogen determination flask, add 0.2g of sodium sulfate, 10g of potassium persulfate and 10mL of concentrated sulfuric acid, place a glass funnel at the flask door, and then install the flask at a 45 degree angle as shown in Figure 1. Heat slowly to keep the solution temperature below the boiling point. After the foam stops, boil it with strong fire. The solution turns black and then gradually becomes transparent. Continue heating for 30 minutes and then cool. Add 200ml. Water is placed in a Kjeldahl nitrogen determination bottle, shaken to dissolve all salts, put in a few glass balls, add 50mL of 50% sodium hydroxide solution, quickly install the distillation device according to Figure 2, and insert the condenser arm into the absorber (i.e., 500ml. conical flask) 34mm below the liquid, and the absorber is filled with 50ml of 4% boric acid solution. The Kjeldahl nitrogen determination bottle is directly heated with an electric furnace. When the solution in the absorber reaches about 200ml., use pH test paper to test it. The distillation is alkaline-free: or when there is a bump in the Kjeldahl nitrogen determination bottle, it means that the steam has been completed. Remove the absorber, wash the condenser with distilled water, wash and add it to the original absorber solution, add 6 drops of mixed indicator, and take the end point when the hydrochloric acid standard solution turns from green to pink. At the same time, perform a blank test. Blank test: Except for not adding the sample, the analytical steps, reagents and dosages that are completely alternate with the determination (except for the period of standard titration solution in titration) must be parallelly operated.
4.4.5 Nitrogen content D% is calculated according to formula (2):
V--V.)CX0. 014 01
Wherein: V is the volume of the blank hydrochloric acid standard solution consumed, mL.
is the volume of the sample hydrochloric acid standard solution consumed, mL; the concentration of the hydrochloric acid standard solution, mol/L
m. Sample mass.g
is the mass of nitrogen in grams equivalent to 1mL of the hydrochloric acid standard titration solution. Figure 1
1-Kjeldahl nitrogen flask: 2-safety ball;
3-condenser 4-conical flask
4.4.6 The average value of the determination is taken as the determination result of the resin nitrogen content. The allowable relative deviation is not more than 5%. 532
(2)
4.5 pH value determination method
4.5.1 Instrument
JB/T 7527-94
pH acidometer: accuracy is 0.1pH unit; glass electrode:
calomel electrode;
beaker: 50ml.
4.5.2 Reagents
Potassium chloride (analytical grade);
pH value 4.003 Standard buffer solution: Weigh 10.21 g of potassium hydrogen phthalate (superior grade) that has been dried at 110°C for 2-3 hours. Dilute to 1000 mL with water
pH value 6.864 Mixed phosphate standard buffer solution: Weigh potassium dihydrogen phosphate (superior grade) that has been dried at 110°C for 2 hours3.4g sodium disodium phosphate (superior purity) 3.55g, diluted with distilled water to 1000mL, d. pH value 9.182 Borax standard buffer solution: weigh 3.81g borax (Na.BO1·10HO) (superior purity), dilute with distilled water to 1000ml
.: If the reagents are in small plastic packaging supplied by the reagent store, prepare the standard buffer solution according to the instructions. 4.5.3 Determination procedure
Glass electrode, soak in distilled water for more than 24h before use, rinse immediately after use, and store in distilled water: In order to keep the instrument zero point stable, the instrument needs to be preheated for more than 0.5h before use; b.
Take 40ml of the homogenized sample and place it in a 50ml beaker and bring it to room temperature. Adjust the temperature compensator on the acidometer to room temperature, and then operate the instrument according to the instruction manual of the acidometer to read the pH value. 4.6 Determination method of tensile strength of resin sand 4.6.1
Instruments and equipment
SWY hydraulic strength testing machine:
NRJ-411 cement mortar mixer, capacity 3kg+*8” standard test block model, in accordance with GB2684; platform scale: 10kg;
balance: 500g, sensitivity 0.5g,
100g, sensitivity 0.1g*
hair hygrometer.
4.6.2 Drugs and materials
Standard sand; should comply with the provisions of ZBJ31006: b.
p-Toluenesulfonic acid (QB85-9-24 ) 70% aqueous solution of reagent. 4.6.3 Test conditions: sand temperature 20±2℃; room temperature 20±2℃C, relative humidity (50±5)%. 4.6.4 Determination procedure
Preparation of the mixture: Take 1000g of standard sand and put it into the mortar mixer. After starting, add 7.5g of p-toluenesulfonic acid aqueous solution immediately. Stir for 1nin, add 15g of resin (the resin does not contain any additives), stir for 1min and then discharge the material: Sample preparation: Pour the above mixture into an "8" shaped core box, manually shape and flatten it, put it on the core board, open the core box, and the shaping is completed. Every h.
group of samples is made 5 pieces, the test block weight is 67±1g, and the test block should The molding is completed within 10 minutes after sand mixing; c. Placement hardening: The prepared sample is naturally hardened for 24 hours under the specified test conditions. d. Determination of the tensile strength of the process sample: Determine the strength of the 24-hour test as required. In the strength testing machine, allow the plane of the four rollers in the fire to stick to the waist of the sample, turn the hand wheel to gradually load until the sample breaks, and its tensile strength value can be directly read from the strength meter.
4.6.5 Result calculation: Determine the strength values of 5 samples, then remove the maximum and minimum values, and take the average value of the remaining values as the sample strength value.
JB/T7527-94
4.6.6 Allow Difference: Any of the three values shall not differ from the average value by more than 10.0%. If exceeded, the test shall be repeated from 4.6.4.
7 Test report
The test report shall include the following contents:
Indicate that this standard is followed;
Test name, model, batch number;
Test results;
Test date, test personnel.
Additional remarks:
This standard was proposed and coordinated by the National Foundry Professional Standardization Technical Committee. This standard was drafted by the Environmental Protection Science Research Institute of the Ministry of Light Industry. The main drafters of this standard are Wu Linxiu, Wang Zhifang, Ma Xiuqing, and Chai Shudun. 534
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