995 neutral silicone adhesive is high strength, can bear large load, and aging resistance, fatigue resistance, corrosion resistance, stable performance in the expected life, suitable for bearing structural parts bond adhesive. Mainly used for bonding metal, ceramic, plastic, rubber, wood and other materials or between different materials, can partially replace welding, riveting, bolt connection and other traditional forms of connection. The following Xiangyang Auman Environmental protection 995 neutral silicone rubber manufacturer Xiaobian detailed introduction of how to use structural adhesive and silicone structural adhesive method.

         1, how to use structural adhesive?

         Silicone structural adhesive should be used in the temperature of 5℃-405℃, the relative temperature of 40%-80%r clean environmental conditions, so that better bonding effect can be obtained. After cleaning the substrate near the surface to be bonded should be affixed with temporary protective tape, if you want to use the base coating should be carried out before sizing. Single-component structural adhesive can be directly extruded from plastic tube or sausage type packaging by manual or pneumatic colloid. Two-component structural adhesive must be sizing with special sizing mixing equipment. The extrusion action of structural glue should be continuous, so that the glue is uniformly and continuously extruded with a cylindrical nozzle, and the diameter of the nozzle should be less than the thickness of the nozzle, so that the nozzle can extend into one second of the depth. The nozzle moves evenly and slowly, and the nozzle is filled with sealant to prevent bubbles or holes from moving too fast. The usual method is to press the excess structural glue outside the interface into the interface with a scraper and scrape the interface surface flat in sequence, so that the glue is in contact with the side of the interface, and then remove all the temporary protective tape. After the above process, the unit should be immediately affixed with the date and number of the content of the label, horizontal play in the curing area for maintenance, in the process of moving the aluminum frame and the glass is not allowed to produce the slightest displacement and dislocation, otherwise it will affect the bonding quality of the structural adhesive curing area must be clean, with good ventilation conditions, the temperature should be maintained 5℃-40℃. Relative temperature should be maintained at 40%-80%; If the temperature is below 50%, the curing time of the unit should be extended. The unit must be at rest and under the condition of no force and curing enough time, one component structural adhesive at least 21 days, two component structural adhesive at least 14 days, so that the structural adhesive produce enough adhesive force, after passing the glue inspection unit products can be shipped and installed. The user should pay attention to the design width of the rubber joint is greater than 16mm, should try to use the double-sided glue method, that is, the double-sided rubber strip in the middle of the rubber joint, on both sides of the rubber strip sizing, so that the curing speed of the rubber, to avoid the influence of the deep curing of the rubber due to the poor air permeability of the double-sided rubber strip.

         2. The use and requirements of 995 neutral silicone adhesive

         2.1 Structural adhesive shall be constructed in the specially set glue room, which is required to be clean and dust-free, fire-free and ventilated. The indoor temperature shall be controlled at 23±5℃, and the relative temperature shall be controlled at 70%±5%. Glue injection operator must receive special business training, and pass the actual operation examination, can be licensed to operate. It is strictly prohibited to use expired silicone structural adhesive, and it is strictly prohibited to use silicone structural adhesive that has not done compatibility test, butterfly test and other related inspection, and all inspection parameters are qualified.

         2.2. Cleaning of glue injection. In strict accordance with the standard specifications, design drawings and process requirements, the use of cleaning agents, cleaning cloth, protective tape and other auxiliary materials. The cleaning of the substrate at the glue place, for non-oily pollutants, usually the mixed solvent of isopropyl alcohol 50% and water 50%; For oily contaminants, xylene solvent is usually used. Cleaning cloth should be clean, soft, non-depilable white or primary-color cotton cloth. Do not dip the cloth into the container of cleaning agent to avoid contamination of the whole solvent. When cleaning, the "two wipe" process is used for cleaning. After cleaning, the cleaned part is never allowed to contact with hands or other sources of pollution, otherwise it should be cleaned again. After cleaning, the substrate must be injected within 15-30 minutes, otherwise it should be cleaned for a second time.

         2.3. Mixing of structural adhesive. Two-component silicone structural adhesive should be mixed with a special two-component silicone glue machine. When mixing, the glue machine should be cleaned in accordance with the instructions of the glue machine, the glue nozzle should be adjusted, and then the two-component sealant should be fully mixed according to the prescribed mixing ratio. In order to control the mixing of structural adhesive, butterfly sample and glue cup should be set aside in each mixing process, timely check the mixing of structural adhesive, and do a good job on duty records. The butterfly test is to check whether the structural glue is fully mixed. The structural glue is uniform in color and fully mixed before gluing. The butterfly sample number should be recorded in the whole mixing process. The glue cup test is used to check the mixing ratio of two-component silicone structural adhesive base and curing agent.

         2.4. Glue injection of structural glue. Structural glue must be injected with mechanical glue, glue should be injected in order to discharge the air in the glue gap; The nozzle of the glue gun should be inserted into the appropriate depth, so that the glue is continuously, evenly and fully injected into the glue gap, and bubbles are not allowed to appear; The pressure should be adjusted at the joint ** There is enough silicone structural adhesive. In the process of gluing, attention should be paid to observe the color change of silicone structural glue, in order to judge the change of the mixing ratio of structural glue, once the mixing ratio of structural glue changes, should be immediately shut down for maintenance, and should be the change part of the colloid cut off, fill qualified structural glue. After gluing, use a scraper to flaten, scrape away the excess structural glue, and trim the exposed surface, so that the surface is smooth and smooth, no bubbles in the seam. Glue injection records should be made in time. The finished glass assembly after gluing shall be sampled for cutting and stripping test to check the bonding firmness and curing degree.

         3, 995 neutral silicone adhesive use method

         3.1, single component silicone structural adhesive can be directly coated between aluminum and glass bonding, it depends on the absorption of moisture in the air and hydrolysis, condensation reaction from the surface to the inside and curing, glue indoor cleaning, temperature is not less than 23℃, relative humidity is not less than 40%, otherwise it will affect the curing, reduce the strength of the adhesive layer.

         3.2. Single component silicone structural adhesive is acidic and neutral. When acidic adhesive is cured, it releases acetic acid, which corrods the film layer of the coated glass produced by vacuum magnetron sputtering for the curtain wall of the hidden frame.

         3.3, two-component silicone structural adhesive must be added to the base adhesive before use, in the special glue machine fully mixed between coating aluminum and glass, bonding curing. The two - component glue is neutral.

         3.4, silicone structural adhesive has a prominent characteristic. That is, there is a compatibility problem between the glue and the bonded aluminum, glass and foam strips. To do the compatibility test, this test can not be done at home for the time being. If the compatibility test results show that the structural adhesive is incompatible with one of the three materials, even in the bonding process, when the various strength indicators are up to the requirements. After half a year or a little longer, the silicone structural adhesive will begin to change color and deteriorate into a liquid state so as to lose its bonding ability, and the glass will fall down, causing serious consequences. Therefore, for the long bonding ability of silicone structural adhesive, compatibility test must be done.

         4, structural adhesive service common problems analysis

         4.1. Particle agglomeration and pulverization of Component B

         If the particle agglomeration and powder of Component B occur, there are two reasons: first, this phenomenon has occurred in the upper layer before use, because the packaging is not well sealed, the crosslinking agent or coupling agent in component B are active compounds, easy to react with water and gas in the air, this batch should be returned to the manufacturer. Second, when the machine is stopped in the process of use, the phenomenon of particle agglomeration and pulverization occurs when the machine is turned on again, indicating that the sealing of the press plate and the glue material is not good, and the equipment should be contacted to solve the problem.

         4.2. The glue machine produces glue slowly

         When the product is used for the first time, the glue speed is too slow in the glue making process of the glue making machine. There are three possible reasons: (1) The poor liquidity of A component, (2) the pressure plate is too large, and (3) the air source pressure is not enough. When determining the cause (1) or cause (3), we can solve it by adjusting the pressure of the glue gun; When the root cause (2) is identified, the problem can be resolved by ordering barrels of matching caliber. If the glue speed is slow in the normal use process, it may be that the mixing core and the filter screen are blocked, once found, it is necessary to clean the equipment in time.

         4.3 Too fast or too slow pulling time

         The breaking time of structural adhesive refers to the time after colloid mixing from paste to elastomer, generally tested every 5 minutes. There are three factors affecting the dry curing of rubber surface: (1) The influence of the proportion of A and B components; (2) Temperature, humidity (where temperature is the main influence); (3) The product itself has defects. According to the reason (1) the solution is to adjust the ratio of proportion, increase the proportion of B component can shorten the curing time, the rubber layer becomes hard and brittle; Reducing the proportion of curing agent will prolong the curing time, the adhesive layer becomes softer, toughness increases and strength decreases. Generally, the volume ratio of component A: B can be adjusted within the range of (9 ~ 13:1). If the proportion of component B is high, the reaction speed is fast, and the breaking time is short. If the reaction is too fast, the dressing and stopping time will be affected; if it is too slow, the colloid drying time will be affected. In addition, when the construction temperature is too high or too low, we can appropriately reduce or increase the proportion of B component (curing agent), so as to achieve the purpose of adjusting the surface drying and curing time of colloid. If the product itself is a problem, you need to replace the product.

         4.4 "Flower glue" appears in the process of gluing.

         Floral gum is produced by uneven mixing of A/B component colloid and appears locally with white stripes. The main reasons are: ⑴ Glue machine B component pipeline blockage; ⑵ The static mixer has not been cleaned for a long time; ⑶ The scale is loose and the glue speed is not uniform; (4) Change the manufacturer or brand has not adjusted the equipment process parameters; According to the reasons (1) and (2), it can be solved by cleaning the equipment; For cause (3), it is necessary to check the proportional controller and make appropriate adjustments.

         4.5, in the process of gluing colloidal crust or vulcanization

         When the two-component glue occurs local curing in the mixing process, the glue shot out of the glue will appear crust or vulcanization phenomenon. When there is no abnormal curing and glue speed, and the glue still has crust or vulcanization phenomenon, it may be that the equipment downtime is long, the glue gun is not cleaned or the gun is not thorough enough, and the crust or vulcanization glue needs to be washed clean after construction.

         4.6. There are bubbles inside the glue

         In general, the colloid itself is no bubbles, colloid bubbles are likely to be mixed with air in the process of transportation or construction, such as: (1) when replacing the rubber bucket exhaust is not clean; The components in the machine after the pressure plate is not pressed down, resulting in incomplete bubble. Therefore, in the use of the front bubble should be thorough, in the use of the process should be correct operation of the glue machine, the best seal to prevent air from entering. If it is suspected that the product itself contains bubbles, it can be determined by the butterfly test.

         4.7. Poor bonding with substrate

         Sealant is not... Glue, so in practical applications can not ** and all substrates are well bonded. With the diversification of substrate surface treatment and new technology, sealant and substrate bonding speed and bonding effect is different.

         There are three forms of structural adhesive and substrate bonding interface failure, one is cohesion failure, that is, adhesion > cohesion; Second, adhesive failure, that is, adhesive force < cohesion, third, both failure forms, adhesive failure area is less than or equal to 20% is qualified, adhesive failure area is more than 20% is unqualified; When the adhesive failure area exceeds 20%, it is an undesirable phenomenon in practical application. There may be six reasons for the non-sticking of structural adhesive and substrate:

         (1) The use of the substrate itself is difficult to bond, such as PP, PE, due to its high molecular crystallinity, low surface tension, and most substances can not form molecular chain diffusion and entanglement, so can not form strong adhesion at the interface;

         The product bonding range is narrow, can only work on part of the substrate;

         The curing time is not enough. Usually, after the action of two-component structural adhesive, the maintenance is at least 3 days, and the single component should be maintained for 7 days. If the temperature and humidity of the maintenance environment is low, the maintenance time should be extended.

         (4) The proportion of components A and B is not correct. Users in the use of two-component products, must be in strict accordance with the manufacturer's requirements of the proportion of base glue and curing agent ratio, otherwise there may be problems in the early curing, or use later in the adhesion, weather resistance and durability problems;

         ⑸ The base material is not cleaned as required. Due to the existence of dust, dirt and impurities on the surface of the substrate hinder bonding, so it should be strictly cleaned before use to perfect structural adhesive and substrate bonding.

         Failure to apply base coat as required. The use of base coating on the surface of aluminum profile can shorten the bonding time and improve the water resistance and durability of the bonding. Therefore, in practical engineering application, we should use the base coating correctly and strictly avoid degumming caused by improper use method.

         4.8. Incompatible with the attachment

         The reason is incompatible with the attachment is that the sealant and the attachment in contact with the physical or chemical reaction, resulting in the harm of structural rubber discoloration, non-stick with the substrate, structural rubber performance decline, structural rubber life becomes short, etc.

         5, wind power blade structural adhesive safety

         For the safety of blade structure design and use, fatigue testing of structural adhesives is necessary. There are many ways to verify the fatigue resistance of structural adhesives. The full-size blade fatigue test can be used directly, but the blade test takes a long time and costs a lot of money. There are also in the use of sandwich layer test (base material for glass fiber reinforced plastic, intermediate layer for structural adhesive) tensile fatigue test.

         At present, the general method for evaluating the fatigue properties of structural adhesives is the tensile shear mode, the reference standard is ISO 9664:1993(E). Fatigue limit can be obtained through fatigue test, and S-N curve can be drawn to obtain m value, in order to understand the fatigue zone of structural adhesive, and get reference value in the design. Change of fatigue endurance limit of adhesives with different thickness of adhesive layer. S-N curves are drawn in different ways, and the m values are different.

         The above is about Xiangyang Auman environmental protection 995 neutral silicone adhesive manufacturers of silicone structural adhesive how to use and the use of silicone structural adhesive in detail, silicone structural adhesive has high strength, high stability, excellent aging resistance, high temperature resistance and other excellent performance, widely used in the structural bonding of building curtain wall. Auman Xiaobian again reminds silicone structural adhesive before construction should check the compatibility test and adhesion test of glass, aluminum and accessories, the construction process should be carried out in strict accordance with the requirements of each link, so as to achieve the effect of structural adhesive, improve the quality of the project.