Analysis of domestic and foreign group standards for insulating glass sealants.
In recent years, with the in-depth implementation of energy-saving and environmental protection policies in some countries, the requirements for energy-saving buildings have become higher and higher, and the application of energy-saving glass has developed rapidly. The wide use of high-performance insulating glass creates a comfortable living space for people and contributes to energy saving and emission reduction. The production of high-quality insulating glass must have high-quality supporting materials. Among them, the durability of insulating glass sealant is the standard for testing the service life of insulating glass.
At present, dew condensation, water seepage, and even glass debonding often occur in insulating glass in buildings. The main reason is that the sealant used in it is prematurely aged, moisture-permeable, or even bonded. The GB/T11944-2012 "Insulating Glass" standard revised and implemented in 2012 adopts the requirements and test methods of Part 2 of EN1279, correspondingly increases the durability requirements of insulating glass and proposes an expected service life of at least 15 years, correspondingly for the production of insulating glass. The quality of sealant products has put forward higher requirements. In 2017, China Architectural Glass and Industrial Glass Association and LIJIANG Glass refer to European Standards ETAG002, EN15434, and EN1279 and Chinese Standards JC/T914, GB/T29755, JG/T471, JG/T475 to test the durability of various sealants for insulating glass, airtightness, mechanical properties, etc., and formulate a higher level standard for various sealing materials for insulating glass T/ZBH004-2018 "Insulating Glass Sealant", which will be implemented on July 1, 2018. This article expounds the main content of the standard in detail and analyzes the significance of each index and the advanced nature of the standard.
1. The purpose and basis of standard preparation
Relevant standards of insulating glass elastic sealants at home and abroad mainly include: European standards ETAG002, EN15434, and EN1279, Chinese standards GB/T29755, GB24266, and JG/T471, there are many standards and the required technical level is different. Glass quality levels also vary widely. In addition, concerning insulating glass hot-melt sealants, butyl hot-melt sealants, and TPS products are mainly used in China. The standard JC/T914 puts forward quality control requirements for butyl hot-melt sealants, but for TPS products, only enterprises There is no relevant national or industry standard for the technical indicators proposed by myself. To meet the design and material selection and reasonable application of insulating glass bonding, facilitate users to choose products with higher quality and technical level, standardize the quality of domestic TPS products, and improve the reliability and sealing durability of insulating glass sealant bonding structure, the group standard T/ ZBH0042018 "Insulating Glass Sealant".
2. The main contents of the standard
2.1 Standard Terms and Definitions
TPS products originated in Europe, and the full name in English is "thermoplastic spacer". In the Chinese market, it is usually translated directly as "thermoplastic spacer". This product is a hot-melt sealant, and the initial state of the product is the same as that of butyl hot-melt sealant, so it is not accurate to call it a "spacer", and it is more reasonable to call it a "sealant". For this reason, the T/ZBH004 standard clearly defined theProduct terms and definitions - thermoplastic spacer sealant: "Polyisobutylene is used as the main material, and additives such as materials with dry gas function are added to realize the functions of butyl sealant, spacer strip, desiccant and other functions in one, with thermoplasticity Insulating glass sealant".
2.2 Standard Scope and Classification
Standard T/ZBH004 is suitable for the sealant of double-channel sealed insulating glass for refrigeration, decoration, and transportation in buildings and other buildings, and is coordinated with the national standard GB/T119442012. Combined with the actual application of insulating glass sealant products, the standard T/ZBH004 divides insulating glass sealants into hot-melt sealants and elastic sealants according to material properties, and hot-melt sealants are divided into butyl hot-melt sealants and thermoplastic Spacer sealant, used as the first sealing material for insulating glass. According to the basic polymer material, elastic sealant can be divided into silicone-type sealant, polysulfide-type sealant, etc., which are used as the second sealing material for insulating glass.
The elastic sealant is divided into two types according to the different use states of the insulating glass:a) Structural assembly type: silicone structural sealant for structural bonding assembly insulating glass, etc.;b) Sealant for non-structural assembly type non-structural assembly insulating glass, including polysulfide sealant, silicone sealant, etc.
2.3 Standard items and indicators
(1) Hot melt sealant
C Standard T/ZBH004 requires physical and mechanical properties of hot-melt sealant products mainly refer to standard JC/T914-2014, setSee Table 1 for the comparison of configuration items and technical indicators.
Table 1 Requirements for physical and mechanical properties of hot-melt sealants
| Serial Number | Project | T/ZBH 004 technical indicators | JC/T 914-2014 technical indicators | ||
| Butyl Hot Melt Sealant | Thermoplastic Spacer Sealant | ||||
| 1 | Density/(g/cm') | Specified value ±0.05 | Specified value ±0.05 | ||
| 2 | Penetration/ (1/10mm) | 25℃ 130℃ | 35~55 230~330 | 15~30 110~210 | 35~55 210~330 |
| 3 | Shear strength | Standard condition/MPa UV treatment for 168 h Post-change rate/% | ≥0.15 ≤20 | ≥0.35 ≤20 | ≥0.15 ≤20 |
| 4 | Heat aging | Thermal weight loss/% Exterior | ≤0.5 | / | ≤0.75 |
| No cracking, pulverization, loss of viscosity | / | ||||
| 5 | Flexible at -45°C | At least 3 out of 5 samples have no brittle fracture | / | ||
| 6 | Water vapor transmission rate/lg/(m²-d)] | ≤0.8 | ≤0.8 | ||
| 7 | Viscosity/min | ≥50 | / | Optional when requested by the user, No indicator requirement | |
| 8 | Standard water adsorption rate/% | / | ≥3.4 | / | |
It can be seen from Table 1 that the standard T/ZBH004 has the same requirement for the density of hot-melt sealants as the standard JC/T914-2014 and the requirement is ±0.05 of the specified value. The density of the limited product cannot fluctuate too much relative to its standard value, to control the stability of the sealant production process. Penetration is a technical index to characterize the plasticity and hot-press fluidity of hot-melt sealants. If the penetration of the glue at 25°C is too small, it means that the glue is too hard at room temperature, which will affect the overall performance of the glue. On the contrary, the glue will be too soft, and the insulating glass produced will have glue overflow during use, which will affect the useing. The 130°C is the usual glue temperature. The thermoplastic spacer sealant is harder than butyl hot-melt sealant because it needs to play a space support role between two pieces of glass, and its penetration index value is relatively low.
By the way, in order to prevent the internal overflow of the insulating glass sealant, you can use the insulating glass sealant gun freezer to maintain the sealant sealing temperature, and use the fully automatic insulating glass sealing robot/insulating glass manual sealant applicator to achieve uniform glue application.
The bonding of butyl sealant or thermoplastic spacer sealant to the substrate should have a certain shear strength to resist the glass load and some external forces. Considering that ultraviolet rays are the main aging factor in the application process of insulating glass, it is required to shear after ultraviolet irradiation. The shear strength cannot have too much attenuation to ensure the service life of the insulating glass.
The thermal weight loss project is to assess the quality loss of butyl rubber due to the overflow of small molecules under relatively high-temperature conditions. The condition of 130°C is determined by taking into account the usual gluing temperature, and the condition is the same as JC/T914-2014. According to the results of the verification test data, the thermal weight loss index of butyl sealant is set at 0.50%, which is higher than the requirements proposed by JC/T914-2014. The thermoplastic spacer sealant can absorb part of the water vapor because it contains a desiccant inside. Therefore, It is impossible to judge the content of small molecular substances in the sealant itself by thermal weight loss, so this index requirement is not set. Low-temperature flexibility is to examine the flexibility of hot-melt sealants at low temperatures and is used to evaluate the application of materials in low-temperature environments.
The water vapor transmission rate of the insulating glass sealant affects the condensation performance of the insulating glass. If the transmission rate is too high, it will seriously affect the performance of the insulating glass. The test is carried out concerning the method specified in 4.6 of JC/T914-2014. Methods and Standards JG/T471: It applies to the detection of hot-melt sealant and elastic sealant at the same time.
Because thermoplastic spacer sealant has the functions of butyl sealant, spacer strip, and molecular sieve, the standard T/ZBH004 specifies the standard moisture absorption rate for thermoplastic spacer strip products, which is used to evaluate its sealing and dry air performance. The standard moisture absorption rate represents the performance of the thermoplastic spacer sealant product to absorb moisture from the outside (in the hollow glass cavity) and reflects the moisture absorption capacity of the product. The size of the standard moisture adsorption rate affects the initial dew point of insulating glass and the length of service life.
The stickiness item is an index for assessing the relative slip performance between the glass and the spacer of the butyl sealant in the process of insulating glass production. The longer the sticking time, the better the adhesion between the glue and the related substrate, and it is not easy to slide, which is conducive to the safe transfer of the glass panel in the process of making insulating glass. During the processing and production of insulating glass, the outer glass is often in an unsupported suspended state during the movement and placement of the semi-finished insulating glass. The outer glass is completely fixed by the sticking ability of butyl sealant, which can withstand long-lasting The self-weight load of the glass, the better the stickiness, the stronger the outer glass, and there will be no movement and slipping, otherwise, it will affect the product quality and even cause the glass to fall off. In JC/T914—2014, it is only an optional item and has no technical index requirements. Standard T/ZBH004 adds this test method requirement. According to the verification test results, the index is set as N50min. The stickiness has a great relationship with the thickness and size of the sealant sample. The size of the thermoplastic spacer sealant varies with the cavity size of the insulating glass produced, so this test is difficult to assess the actual application status of the product. The standard T/ZBH004 does not This technical index requirement is not specified for thermoplastic spacer sealants.
(2) Elastic sealant
Standard T/ZBH004 is divided into structural assembly type (ie silicone structural sealant) and non-structural assembly type (including polysulfide sealant, silicone sealant, etc.) according to the different states of elastic sealant used in insulating glass. The physical performance requirements of the elastic sealant are the same as the standard requirements, see Table 2.
Table 2 Requirements for Physical Properties of Elastic Sealants
| Serial number | Project | Technical requirements | |
| 1 | Density/(g/cm') | A component | Specified value ±0.05 |
| B component | |||
| 2 | Applicable period/min | ≥30 | |
| 3 | Surface dry time/h | ≤3 | |
| 4 | Hardness/Shore A | 30~60 | |
| 5 | Sag | Vertical/mm | ≤3 |
| Horizontal/mm | No deformation | ||
| 6 | Alkane plasticizer content | None | |
| 7 | Thermogravimetry | There is no significant difference in the patterns | |
| 8 | Water vapor transmission rate | Silicone type | ≤3 |
| polysulfide type | ≤3 | ||
In Table 2, the physical performance tests such as density, surface dry time, sag, and pot life are all required by the existing standard methods in the past. Standard T/ZBH004 requires silicone-type sealants to be free of alkane plasticizers, and it is forbidden to mix inferior plasticizers (such as white oil, etc.). In the previous standards, there were no specific index requirements for the water vapor transmission rate. According to the verification test results, the standard T/ZBH004 stipulated the water vapor transmission rate index values for silicone-type and polysulfide-type sealants, and polysulfide-type sealants. The airtightness of the glue is usually better than that of the silicone-type sealant. Because the structural assembly type sealant involves structural safety,
Its mechanical property requirements are quite different from those of non-structural assembly sealants, so the standar d T/ZBH004 stipulates the mechanical properties respectively, see Tables 3 and 4.
Table 3 Mechanical performance standards of non-structural assembly elastic sealant
| Serial number | Project | Technical requirements | |
| 1 | Tensile adhesion at 23°C | Average Tensile Bond Strength Average Tensile Bond Strength Broken state Initial stiffness | ≤0.6 ≤0.5 OAB interval without perspective damage Adhesive failure area≤10% report value |
| 2 | Tensile adhesion at -20°C Tensile adhesion at 23°C | 1) Average tensile bond strength/MPa; 2) Destroyed state | Adhesive failure area≤10% OAB interval without perspective damage |
| 3 | Tensile adhesion after water-ultraviolet light irradiation | Tensile bond strength average/MPaInitial stiffness change rate K /K ℃Adhesive failure area/% | ≥0.75 0.5≤K/K≤1.10 ≤20 |
| 4 | Elastic recovery rate/% | ≥80 | |
Table 4 Mechanical performance standards of structural assembly elastic sealant
| Serial number | Project | Technical requirements | ||
| 1 | Stretch Adhesion | 23°C | Average Tensile Bond Strength Average Tensile Bond Strength Broken state Initial stiffness | ≤0.6 ≤0.5 OAB interval without perspective damage Adhesive failure area≤10% report value |
| 2 | Stretch Adhesion | -20℃ | Average tensile bond strength/MPa; | ≥0.75 |
| 3 | 80℃ | |||
| 4 | Salt spray environment | Destroyed state | Adhesive failure area≤10% OAB interval without perspective damage | |
| 5 | Acid mist environment | |||
| 6 | Cleaner environment | |||
| 7 | Water - UV Radiation | Average Tensile Bond Strength/MPa Initial stiffness change rate Adhesive failure area/% | ≥0.75 0.5≤K≤1.10 ≤10 | |
| 8 | shear performance | 23℃ | Average shear strength/MPa | Report value |
| Average shear strength/MPa | ≤0.5 | |||
| Adhesive failure area/% | ≤10 | |||
| -20℃ | 1) Average shear strength/MPa; | ≥0.75 | ||
| 80℃ | 2)Adhesive failure area/% | ≤10 | ||
| 9 | Elastic recovery rate/% | ≥95 | ||
| 10 | Tear Resistance | Average tensile bond strength/MPa; | ≥0.75 | |
| Adhesive failure area/10% | ≤10 | |||
| 11 | Fatigue performance | Average tensile bond strength/MPa; | ≥0.75 | |
| Adhesive failure area/10% | ≤10 | |||
| 12 | Creep property b | Displacement/mm | ≤0.10 | |
Note: The test temperature can be set to -40°C according to the actual application environment; b Only suitable for sealants subject to permanent loads
Structural sealants are made into an insulating glass and applied in building curtain walls, especially in high-rise building curtain walls. These complex external forces accelerate the aging of structural sealants. Insulating glass is also affected by surrounding environmental factors during use, such as ultraviolet radiation, rain, low temperature, high temperature, high humidity, salt spray environment, acid fog environment, and other factors that will accelerate the aging of the sealant and reduce its service life. Therefore, it is necessary to set up corresponding testing items and specify technical index requirements to ensure the safety of insulating glass. Therefore, in the process of making the sealant for structural bonding of insulating glass, all the above factors should be considered; for the non-structural sealant for insulating glass, because it has frame support protection, it only needs to be tested at room temperature, high temperature and relatively short time. Test of the tensile strength of the bond after water-ultraviolet light irradiation treatment.
To control the performance attenuation rate of silicone structural adhesives after high temperature, low temperature, rain, light, acid mist, salt spray, and curtain wall cleaning agents, it is stipulated that 80°C, -20°C (-40°C), water-ultraviolet light, The retention rate of tensile bond strength after treatment with NaCl salt spray, SO₂ acid spray and cleaning agent, the index reference standard JG/T471 is set as N75%, and the bond failure area is 010%. It is stipulated that the non-structural seal has a tensile bond strength retention rate of >75% at 60°C and -20°C, and a bond failure area of 0.10%. The time for the silicone structural sealant-ultraviolet light test is 1008h, and for the non-structural sealant for insulating glass, the light time is set as short as 168h due to the frame protection, and the adhesive damage area index is set as 020 according to the verification test results %. The mechanical performance tests and technical index requirements of silicone structural sealant related to shear, tear, fatigue, elastic recovery rate, creep, etc. are specified following the standard JG/T471.
3. Comparison between T/ZBH004 standard and foreign advanced standards
For hot-melt sealants, there are currently no foreign standard reports related to the product. For elastic sealant products, foreign advanced standards mainly include European standards ETAG002-2012, EN15434-2010, and EN1279-2002 (Part 4). The comparison of relevant standards is shown in Table 5.
Table 5 Comparison of elastic sealant requirements between standard T/ZBH004 and foreign advanced standards
| Serial number | Experimental project | EN15434 | ETAG002 | EN1279-4 | T/ZBH004 | |
| Structural | Non-structural | |||||
| 1 | Density | Manufacturer's specified value | Report | / | ||
| 2 | Hardness /Shore A | 30~60 | ||||
| 3 | Applicable period | ≥20 | ||||
| 4 | Surface dry time/h | ≤3 | ||||
| 5 | Droop | / | 0 | |||
| 6 | Infrared spectrum | Report | Non-alkane plasticizer | / | ||
| 7 | Thermo gravimetry | Report | There is no significant difference in the patterns | |||
| 8 | Water vapor permeability | / | Report | Silicone type≤20 Polysulfide type≤15 | ||
| 9 | Gas permeability | / | ||||
| 10 | 23°C Stretch Adhesion | Tensile strength standard value ≥ 0.5MPa Cohesive failure ≥ 90% Report the modulus of stiffness | Tensile strength standard value ≥ 0.5MPa Cohesive failure ≥ 90% Report the modulus of stiffness | OAB interval without perspective damage | Tensile strength standard value ≥ 0.5MPa Cohesive failure ≥ 90% Report the modulus of stiffness | |
| 11 | 60°C Stretch Adhesion | / | / | Tensile strength ≥ 75% of 23°C OAB interval without perspective damage | ||
| 12 | -20°C | Tensile strength ≥ 75% of 23°C | Tensile strength ≥ 75% of 23°C | |||
| 13 | Tensile adhesion after 80℃, NaCl environment, SO2 environment, cleaning agent treatment | Cohesive damage 90% | Cohesive damage 90% | / | Cohesive damage 90% | / |
| 14 | Tensile adhesion after water-ultraviolet light (1.008h) | Tensile strength ≥ 75% of 23°C Cohesive failure ≥ 90% | Tensile strength ≥ 75% of 23°C Cohesive failure ≥ 90% | / | Tensile strength ≥ 75% of 23°C Cohesive failure ≥ 90% | |
| 15 | 23°C Shear | Cohesive failure≥ 90% | Cohesive failure≥ 90% | / | Cohesive failure≥ 90% | / |
| 16 | Elastic recovery rate | 25% fixed elongation ≥ 95% | 25% fixed elongation ≥ 95% | / | 25% fixed elongation ≥ 95% | 25% fixed elongation ≥ 95% |
| 17 | Tear strength | ≥75% of 23℃ | ≥75% of 23℃ | / | ≥75% of 23℃ | / |
| 18 | Fatigue strength | ≥75% of 23℃ Cohesive failure ≥ 90% | ≥75% of 23℃ Cohesive failure ≥ 90% | / | ≥75% of 23℃ Cohesive failure ≥ 90% | / |
| 19 | Creep After unloading force for 24 hours: maximum displacement/mm | μ≤0.1 | μ≤0.1 | / | μ≤0.1 | / |
| 20 | Tensile adhesion after immersion in water | / | / | No damage in the OAB area | / | / |
| 21 | Tensile adhesion after UV treatment | / | / | / | / | |
Note: "/"means no requirement.
It can be seen from Table 5 that the standard T/ZBH004 refers to the relevant content of European standards ETAG002, EN15434, and EN1279, combined with the requirements of various related standards such as Chinese standards JC/T914, GB/T29755, JG/T471, compared with the previous domestic and foreign standards. The standard puts forward more comprehensive requirements on the durability, air tightness, environmental aging resistance, and mechanical properties of various sealants for insulating glass, and has a high technical level. Standard T/ZBH004 stipulates control items such as thermogravimetric analysis, infrared spectral analysis, and density limit indicators to ensure the stability and uniqueness of the product and prevent the harm of white oil sealant; it has set up shear, tear, mechanical fatigue, and other tests The project fully considered the various complex external forces that the structural sealant is subjected to in the actual use process; through the water-ultraviolet light test, acid fog, salt spray, and other test items, the impact of environmental factors on the performance of the structural sealant was fully considered; The performance level of the sealant is measured by the retention rate of mechanical properties, which effectively reflects the durability and stability of the insulating glass sealant.
4. Conclusion
The standard T/ZBH004 draws lessons from domestic and foreign advanced standards, and for the first time in China gives the terms and definitions of thermoplastic spacer sealant products, and stipulates the technical index requirements of this product. Based on the relevant standards of hot-melt butyl sealant and elastic sealant in my country in the past, the technical index requirements of some testing items (such as butyl hot-melt sealant penetration, heat aging, stickiness, etc.) have been improved; elasticity Water vapor transmission rate of sealant, tensile viscosity of water after ultraviolet light Connectivity and other items. The implementation of the standard T/ZBH004 will help improve the quality of Chinese insulating glass sealant products, guide industry personnel to reasonably select high-quality sealant products to produce high-quality insulating glass and promote the progress and development of Chinese building energy-saving technology.
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