This standard specifies the instrument, materials, test steps and result expression for the pouring time limit, gel time and bonding strength test of polyurethane cold-patch glue castable for rubber-sheathed flexible cables for use in mines. This standard is applicable to the performance test of polyurethane cold-patch glue castable for rubber-sheathed flexible cables for use in mines. MT/T 351.4-2005 Test method for polyurethane cold-patch glue castable for rubber-sheathed flexible cables for use in mines MT/T351.4-2005 Standard download decompression password: www.bzxz.net

ICS 33. 120. 99
Registration No.: 15523—2005
Coal Industry Standard of the People's Republic of China
MT/T351.4—2005
Replaces MT/T354--1994
Polyurethane cold patch adhesive for rubber-sheathed flexible cables for mining
Test method for casting material
Issued on 2005-02-14
National Development and Reform Commission
Implementation on 2005-06-01
Normative reference documents
3 Determination method for casting time limit and gel time 4
Determination method for bonding strength
MT/T351.4—2005
MT/T351.4—2005
This standard replaces MT/T354—1994.
This standard is proposed by the Science and Technology Development Department of China Coal Industry Association. This standard is under the jurisdiction of the Coal Industry Coal Mine Safety Standardization Technical Committee. The main drafting unit of this standard: Fushun Branch of China Coal Research Institute. The main drafters of this standard: Yuan Hongjun, Fu Baocan, Zhai Jin, Huang Yilan, Yang Chunli. 1 Scope
Polyurethane cold repair glue for rubber sheathed flexible cables for mining
Casting material test method
MT/T 351.4--2005
This standard specifies the instruments, materials, test steps and result expressions for the pouring time limit, gel time and bonding strength of polyurethane cold repair glue castings for rubber sheathed flexible cables for mining. This standard is applicable to the performance test of polyurethane cold repair glue castings for rubber sheathed flexible cables for mining. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties reaching an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version applies to this standard. GB7594 Rubber insulation and rubber sheath of wire and cable GB8170 Digital rounding rules
3 Determination method of pouring time limit and gel time 3.1 Instruments and appliances
3.1.1 Glass rod
Its diameter and length can meet the requirements of this test, and no specific regulations are made, but it must be a special test rod for stirring in chemical experiments. 3.1.2 Thermometer
The measurement range is 0~100℃, and the graduation value is 1℃. 3.1.3 Timer
The graduation value is 1s.
3.2 Determination steps
3.2.1 Determination of pouring time limit
3.2.1.1 Before the test, pre-treat the matching samples of component A and component B and place them in an environment with a temperature of (23±2)℃ for 24 hours. 3.2.1.2 Pour all the component B into the container containing component A, stir with a glass rod and start the timer to start timing until the mixture is evenly mixed (at least 2 minutes) and then stop stirring. 3.2.1.3 Insert a clean glass rod vertically into the castable material for about 40mm, and immediately pull it out about 100mm from the material surface. At this time, the castable should flow down from the glass rod evenly and continuously. Test once every 10 to 15 seconds until the castable just flows down from the glass rod in a drop shape, and record the time displayed on the timer. This time is the pouring time limit. 3.2.2 Determination of gel time
After measuring the pouring time limit, continue timing, insert a clean glass rod vertically into the castable material for about 10 mm, immediately pull it out of the material surface, and observe its flow. Test once every 60 seconds until the castable material stops dripping, stop timing and write down the timer display value, this time is the gel time.
3.2.3 Expression of measurement results
The pouring time limit and gel time are expressed in minutes. The timer reads to the second place and is rounded to the unit of minutes according to GB8170. 3.3 Precautions
When stirring the castable, be sure to avoid bringing air into the material. 1
MT/T351.4—2005
4 Method for determination of bonding strength
4.1 Instruments, tools and materials
4.1.1 Constant temperature box:
Measuring range: room temperature 200℃
4.1.2 Temperature fluctuation range should not be greater than ±2℃. 4.1.3 Tensile testing machine:Www.bzxZ.net
Constant speed testing machine with stress-stroke curve drawing device. 4.1.4 Multi-cavity casting mold:
The multi-cavity casting mold is shown in Figure 1.
1~-mold;
Rubber test piece;
Polyethylene film.
Figure 1 Casting mold for bonding strength test
4.1.5 Area meter and polyethylene film (or similar material). 4.1.6 Rubber test piece:
Specifications are 25mm×150mm×6mm, and the rubber performance should comply with the corresponding provisions of GB7594 on rubber sheaths of wires and cables. 4.2 Sample preparation
4.2.1 After wiping the side of the rubber test piece that is bonded to the sample with sandpaper, embed the rubber test piece into the lower part of the mold cavity as shown in Figure 1. 4.2.2 Attach a polyethylene film to one end of the test piece as shown in Figure 1. Its width should be greater than the width of the mold cavity and its length is about 30mm. 4.2.3 Pour the prepared casting material evenly into the mold cavity and fill it. 4.2.4 Demolding after 3h, the demoulding sample is allowed to stand in the ambient temperature for 20 to 24h, and then in a constant temperature box at a temperature of (65±2)℃ for 16h. 2
4.3 Determination steps
MT/T 351.4-—2005
The two different materials at the end of the sample with polyethylene film attached are clamped on the upper and lower clamps of the tensile testing machine respectively, and the peeling test is carried out at a pulling speed of (100±10) mm/min, and the stress-stroke curve is drawn at the same time. 4.4 Expression of determination results
4.4.1 Calculation of average bonding force:
Use an area meter to measure the area occupied by 50% of the middle part of the stroke in the stress-stroke curve diagram, and calculate the average bonding force according to formula (1): F㎡fA/L
Where:
--average bonding force, N;
--area occupied by 50% of the middle part of the stroke of the stress-stroke curve, mm2;--length of 50% of the stroke of the stress-stroke curve, mm; f--stress represented by each millimeter of the stress coordinate of the stress-stroke curve, N/mm. 4.4.2 Calculation of bonding strength:
Calculation formula is as follows (2):
C= F/B
Where:
- bonding strength, N/mm;
B——specimen width, mm.
Carry out two parallel tests, take the arithmetic mean as the final result of bonding strength, and round it to one decimal place after the decimal point according to GB8170.
4.5 Precautions
4.5.1 Sample preparation and testing should be carried out at ambient temperature (i.e. (23 ± 5) ℃). 4.5.2 When preparing the sample, the mold must be placed horizontally. 3
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