The aluminum-plastic composite panel for building curtain wall is a three-layer composite panel used as a building curtain wall material using flame-retardant plastic as the core material, aluminum on both sides, and covered with decorative and protective coatings or films on the surface of the product. According to its combustion performance, it can be divided into flame retardant type (FR) and high flame retardant type (HFR). Because the core material used has been treated with flame retardant, the aluminum-plastic composite panel for building curtain wall not only has the characteristics of heat insulation, sound insulation, light weight, pollution resistance, corrosion resistance, and high bending strength, but also has a significant flame retardant effect, which can effectively inhibit the spread of fire.
In order to meet the functional requirements, the aluminum-plastic composite panel used for the building curtain wall and the materials used in it need to meet certain technical requirements, for example, the aluminum selected for the curtain wall panel should meet the specified series of relevant standard requirements, or other series of aluminum alloys with better corrosion resistance and mechanical properties, and its surface coating should be fluorocarbon resin coating, or other coatings with equivalent or better performance.
Test items
Strengthening the quality control of curtain wall panels is an indispensable part of product production and application, and it is one of the effective methods to carry out scientific quality inspection of curtain wall panels, and the testing items mainly include:
Aluminum thickness, appearance quality, allowable deviation of dimensions, coating thickness and properties (coating thickness, surface pencil hardness, gloss deviation, flexibility, adhesion, impact resistance, abrasion resistance, hydrochloric acid resistance, oil resistance, alkali resistance, nitric acid resistance, solvent resistance, stain resistance, artificial weather aging resistance, salt spray resistance), physical and mechanical properties (flexural strength, flexural elastic modulus, penetrating resistance, shear strength, drum peel strength, temperature difference resistance, thermal expansion coefficient, heat deflection temperature, hot water resistance), Combustion performance (calorific value of core combustion, plate burning performance grade, additional information on sheet burning performance).
Detection method
Aluminum thickness
Peel off the aluminum from the specimen as a specimen, measure the thickness of the aluminum itself with a measuring tool that meets the requirements, the measurement point should contain at least four corners and a center, and record and calculate the final result according to the actual measurement.
Appearance quality
Under the condition of natural light that is not directly exposed to sunlight, the curtain wall panels are put together side by side in the same production direction by the prescribed method, and the visual inspection is carried out at a distance of 3m from the center of the assembled panel surface, and the maximum size of the various defects observed is measured with a ruler that meets the requirements.
Allowable deviation of dimensions
The measurement and calculation of the allowable deviation of the size include length and width, thickness, diagonal difference, edge straightness, warpage, etc., and the measuring tool should be selected according to the requirements and measured in accordance with the specified method.
Coating properties
There are many items involved in the testing of coating performance, so we will not expand them one by one here, but attention should be paid to the calculation and value of the test results.
Flexural strength, flexural modulus of elasticity
Prepare the specimen according to the requirements, measure the width and thickness of the middle part of the specimen with vernier calipers, install the specimen on the testing machine according to the specified requirements, apply the test load at a constant speed of 7mm min until the maximum value, record the load-deflection curve at the same time, and calculate the flexural strength and flexural elastic modulus according to the corresponding formula. The flexural strength and flexural elastic modulus of the three groups of specimens were measured in the positive upward longitudinal direction, the front upward transverse, the back upward longitudinal and the back upward transverse respectively, and the arithmetic mean of each group was used as the measurement results of the group.
Penetration resistance, shear strength
Select the testing machine and fixture that meet the requirements of the standard, and use the micrometer to measure the thickness of the specimen according to the required method. Drill an assembly hole with a diameter of 11mm in the center of the specimen, then install the specimen according to the requirements, load it on the punch at a uniform rate at a specified rate, record the maximum load borne by the specimen, that is, its penetrating resistance, and calculate the shear strength according to the corresponding formula. The arithmetic mean value of all specimens was used as the test result.
Drum peel strength
The specimen is installed in the fixture of the testing machine according to the prescribed procedure, and the test is carried out according to the specified loading speed, and the load-peeling distance curve is recorded by the automatic recording device, and the specimen can be unloaded when it is peeled to 150mm 180mm. Taking 3 specimens as a group, the average peel strength and minimum peel strength of each specimen in each group of specimens were measured according to the requirements, and the final result was calculated.
Resistance to temperature differences
The specimen is kept at a constant temperature of -40 2 for at least 2 h, and then taken out and put into 80 2 for at least 2 h, and this is a cycle. After 50 cycles, the abnormal changes in the appearance of the test piece such as abnormal changes such as abnormal deformation, bubbling, spalling, glue opening, coating cracking and so on, the adhesion test was carried out according to the required method, and the decline rate of the average value of the pulley's peeling strength before and after the temperature difference test was measured and calculated.
Coefficient of thermal expansion
With an accuracy of 0The 02mm vernier caliper measures the length of the corresponding measurement position under the specified temperature conditions, calculates the thermal expansion coefficient of each measurement position accordingly, and takes the arithmetic average of all the measured values as the final result. It should be noted that before measuring the length, the specimen should be kept at a constant temperature at the corresponding temperature for at least 1h.
Heat deflection temperature
The prepared specimen is adjusted in state, the specimen is laid flat as required, and a certain force is applied to it to make the maximum bending normal stress of the specimen reach 182MPa, the relative change of the midpoint deflection of the specimen before and after heating reaches 0The temperature at 25 mm is used as the heat deflection temperature of the specimen. Taking three specimens as a group, the heat deflection temperature of each group of specimens under the specified mode was measured respectively, and the arithmetic mean value of each group of specimens was calculated as the result value of the group.
Hot water resistance
The specimen should be immersed in 98 2 distilled water at a constant temperature for 2h, and the specimens should be avoided from touching each other and channeling during the process. Then let the specimen be naturally cooled to room temperature in the distilled water, and the specimen is taken out to dry, and the specimen is not broombed, glued, peeling, cracking and coating discoloration and other abnormal changes in appearance. The adhesion test was carried out according to the prescribed method, and the worst performance value of all specimens was taken as the test result.
Combustion performance
The combustion calorific value of the core material should be tested in accordance with GB T 14402, and the additional information on the combustion performance grade and burning performance of the curtain wall panel should be tested in accordance with the relevant methods in GB 8624-2012. The preparation of the sample should meet the requirements, the core material specimen can be peeled off from the curtain wall panel, there should be no polymer adhesive film on the surface, and the final result is calculated according to the obtained test data.
Precautions
If there is a dispute over the results of visual color difference, the color difference arbitration test should be carried out in accordance with the relevant provisions of GB T 11942, and the consistency of the production direction of the test piece should be maintained.
Before the drum peel strength test, the specimen should be visually inspected in accordance with the requirements of the relevant standards, the qualified specimens should be numbered, and their width and thickness values should be measured and recorded. In the hot water resistance test, the opening of the aluminum and core materials within 10mm from the edge of the specimen is not counted.