peculiarity
One-component room temperature vulcanized silicone:
RTV-1 adhesive is used as an adhesive together with polysulfide rubber, urethane rubber, etc., but RTV-1 adhesive has the following characteristics:
1. All components are mixed and packaged in a container, as long as the rubber is extruded, it can be vulcanized into elastomer when it encounters moisture in the air, which is easy to use and coat;
2. The temperature has little effect on the viscosity of the rubber material, and the same operation method can be used regardless of cold winter and hot summer;
3. According to the need, it can be made into viscosity flow products for coatings, and can be made into non-flowing thixotropic products for vertical gap sealing;
4. Maintain rubber elasticity over a wide temperature range (-60°C to 300°C);
5. Excellent adhesion to most substrates, if primer is used, the adhesion is better;
6. Humidity has little effect on vulcanization hardness;
7. Excellent electrical performance;
8. No endothermic or exothermic during vulcanization;
9. Excellent resilience of compression or stretching;
10. Except for acetic acid type and ketone oxime type, there is no corrosiveness, and the vulcanized rubber is chemically inert;
11. Excellent heat resistance, cold resistance and weather resistance;
12. It can be made into transparent products, and can also be adjusted into various colors.
Two-component room temperature vulcanized silicone rubber:
Compared with RTV-1 gels and other two-component systems, RTV-2 adhesives have the following advantages:
1. It is easy to use, no heating and pressurization equipment, only the basic rubber material needs to be mixed with the catalyst, and it can be vulcanized into elastomer without endothermic or exothermic problems. Although polyester resin and epoxy resin can be used under similar conditions, they have the disadvantage of heat release when curing.
2. According to the needs of processing and application, it can be made from low-viscosity oil to high-consistency paste or putty glue products, and vulcanized rubber with different properties can be obtained by changing the catalyst variety, dosage and vulcanization conditions.
3. The vulcanization process of RTV-1 glue is slowly vulcanized from the surface to the inside by contacting the moisture in the air, while RTV-2 glue is vulcanized at the same time inside and outside.
4. RTV-1 adhesive has good adhesion to most substrates, while RTV-2 adhesive has good mold release properties for most substrates, coupled with small shrinkage, so it is widely used in making soft molds. RTV-2 adhesive can also achieve good adhesion when a tackifier is added to the compound or the surface of the substrate is treated with a primer first.
5. RTV-2 rubber has the heat resistance, cold resistance, weather resistance, arc resistance and electrical insulation of mixed silicone rubber and RTV-1 rubber, and maintains rubber characteristics in a wide temperature range (-60 °C to 300 °C), and has good vibration absorption.
Condensed type
broadcast
edit
It is the most common kind of room temperature vulcanized silicone rubber, and its raw rubber is usually hydroxyl terminated polysiloxane, and then combined with other compounding agents and catalysts to form a rubber compound, the viscosity of this rubber material can range from 100 centime to 1 million centi.
Vulcanization method
The vulcanization reaction of condensed one-component room-temperature vulcanized silicone rubber is initiated by moisture in the air.
The vulcanization reaction of condensed two-component room-temperature vulcanized silicone rubber is not initiated by moisture in the air, but by a catalyst. Usually the silica rubber, filler, and cross-chain agent are packaged as one component, and the catalyst is packaged separately as another component, or other combinations are used, but the catalyst and the cross-chain agent must be packaged separately. Regardless of the type of packaging, curing only begins when the two components are completely mixed together.
The vulcanization reaction of addition two-component room temperature vulcanized silicone rubber is accomplished by the addition reaction of silicon-hydrogen bonds and silica vinyl in the presence of a platinum metal catalyst.
Crosslinkers
Condensed silicone rubber The commonly used crosslinker is ethyl orthosilicate and the catalyst is dibutyltin dilaurate. and add appropriate fillers and additives depending on the nature of the desired end product. Over the years, many countries have banned the addition of dibutyltin in food bags and plasma bags due to the fact that tin dibutyl dilaurate is a moderately toxic substance, and has basically been replaced by octyltin with low toxicity.
The crosslinker of additionally molded silicone rubber is generally an oligomeric hydrosilicon. Catalysis is performed with a Karst catalyst or chloroplatinic acid.
Vulcanization time
The curing time of two-component condensed room-temperature vulcanized silicone rubber depends mainly on the type of catalyst, the amount used, and the temperature. The more catalyst is used, the faster the vulcanization and the shorter the shelving time. At room temperature, the shelving time is generally a few hours, and if you want to extend the shelving time of the compound, you can use the cooling method. Two-component condensed room temperature vulcanized silicon rafter takes about a day to reach full cure at room temperature, but only 1 hour at 150°C. The cohesive effect by using the accelerator γ-aminopropyltriethoxysilane can significantly increase its curing speed.
performance
Two-component room temperature vulcanized silicone rubber can maintain elasticity for a long time in the temperature range of 65~250 °C, and has excellent electrical properties and chemical stability, can resist water, ozone, weather aging, coupled with simple use, strong process applicability, therefore, can play a protective role in moisture (anti-corrosion, shockproof, etc.). It is possible to improve performance and stabilize parameters. Two-component room-temperature vulcanized silicone rubber is particularly suitable for deep potting materials and has a fast vulcanization time, which is superior to one-component room-temperature vulcanized silicone rubber. [1]
apply
Two-component room temperature vulcanized silicone rubber has excellent anti-stick properties after vulcanization, and the shrinkage rate is very small during vulcanization, so it is suitable for manufacturing soft molds, in addition, the high simulation performance of two-component room temperature vulcanized silicone rubber can be used to reproduce a variety of exquisite patterns. For example, it can be used to reproduce ancient bronzes in the reproduction of cultural relics, and can be used to copy the skin patterns of snakes, pythons, crocodiles and pangolins in the production of artificial leather. [2]
Precautions
The binder, crosslinker and catalyst are first weighed separately and then mixed in proportion.
Usually the two components should be supplied in different colors, so that the mixing of the two components can be visually observed, and the mixing process should be handled with care to minimize the amount of entrapped gas. After the rubber is mixed (uniform color), the bubbles can be removed by standing or depressurizing (vacuum degree 700 mm Hg), and after all the bubbles are discharged, they can be vulcanized into silicon eraser at room temperature or at a specified temperature for a certain time.
Product category:
broadcast
edit
In addition to methyl, the side groups on the silicone backbone of two-component room temperature vulcanized silicone rubber can be replaced by other groups such as phenyl group, trifluoropropyl group, cyanoethyl group, etc., in order to improve its low temperature resistance, heat resistance, radiation resistance or solvent resistance. At the same time, heat-resistant, flame-retardant, thermally conductive and electrically conductive additives can also be added as needed to prepare silicone rubber with ablation-resistant, flame-retardant, thermally conductive and electrically conductive properties.
Methyl room temperature vulcanized silicone rubber
Methyl room temperature vulcanized silicone rubber is an old variety of general silicone rubber, which has the advantages of water resistance, ozone resistance, arc resistance, corona resistance and weather aging resistance. It can be used in a temperature range of 60~200°C. Therefore, it is widely used as a pouring and sealing material for electronic and electrical components, and a moisture-proof, shockproof, high and low temperature resistant pouring and sealing material for instrumentation. It can also be used to make molds for casting polyester resins, epoxy resins and low melting point alloy parts. It can also be used as an impression material for dentistry.
Methyl room temperature vulcanized silicone rubber is coated on cotton cloth and paper bags, and can be made into conveyor belts and packaging bags for conveying sticky goods.
Methyl biphenyl room temperature vulcanized silicone rubber
In addition to the excellent performance of methyl room temperature vulcanized silicone rubber, methyl biphenyl room temperature vulcanized silicone rubber has a wider service temperature range (-100~250 °C) than methyl room temperature vulcanized silicone rubber. Low phenyl room temperature vulcanized silicone rubber (108-1) with phenyl content of 2.5~5% can maintain elasticity at low temperature of -120 °C, and is the best variety of silicone rubber with low temperature performance. Room temperature glue (108-2) with phenyl content of 10~20% has good radiation resistance, ablation resistance and self-extinguishing properties, if a certain amount of heat-resistant additives such as Fe2O3 are added to it, it can improve the thermal aging performance, and is suitable for use at high temperatures above 250 °C or as ablation-resistant putty coating and encapsulation materials.
Methylphenyl room temperature adhesives, like other room temperature adhesives, can be used for dipping, impressioning, and delamination. If you want to increase the adhesion with other materials, you must use the material before the surface treatment, the surface treatment of the material is as follows: clean the surface of the material with acetone solvent 1~2 times, then treat it with surface agent 1~2 times, bake it in the oven at 60 °C for several minutes, and then form a layer of film with few sticky hands on the surface of the material, and then it can be glued.
Methyl block room temperature vulcanized silicone rubber
Methyl block room temperature vulcanized silicone rubber is a modified variety of methyl room temperature vulcanized silicone rubber, which is a copolymer of polydimethylsiloxane (107 rubber) and methyltriethoxysilane oligomer (molecular weight 3~5) with a hydroxyl head. Under the catalysis of dibutyltin dilaurate, the hydroxyl group in polydimethylsiloxane and the ethoxy group in polymethyltriethoxysilane are condensed to form a polymer with a three-way structure, and the vulcanized ejectable body has higher mechanical strength and adhesion than methyl room temperature vulcanized silicone rubber, and can be used for a long time in a temperature range of 70~200 °C.
Methyl block room temperature vulcanized silicone rubber has shockproof, moisture-proof, waterproof, breathable, ozone resistance, weather aging resistance, weak acid and alkali resistance. It has good electrical insulation, good adhesion, and low cost. Therefore, it can be widely used in potting, coating, impression, release, release drug carrier, etc. The electronic components encapsulated with methyl block room temperature glue have the functions of shockproof, moisture-proof, sealing, insulation, and stabilizing various parameters. Applying methyl block room temperature adhesive directly to the speaker can reduce and eliminate the mid-frequency points of the speaker, and the resonant frequency performance of the speaker can be reduced by about 20 Hz after vulcanization. It can be used as an anti-sticking agent for paper after a certain amount of additives are added to the methyl block at room temperature. After coating a thin layer of methyl block room temperature glue on the candy and biscuit conveyor belts in the food industry, the anti-stick performance of the canvas can be improved, thereby improving the appearance of the food and increasing the utilization rate of raw materials.
Adding an appropriate amount of fumed silica to the methyl block room temperature glue can be used to install the joints of window glass, curtain walls, window frames, prefabricated panels, and expansion joints of airport runways. In addition, it can also be used as an adhesive for magnetic cores and templates in electronic computer memory, and as an adhesive for conductive silicone rubber and non-conductive silicone rubber. Treating fabrics with methyl block room temperature vulcanized silicone rubber improves the feel, softness and abrasion resistance of the fabric.
Room temperature vulcanized silicone rubber
Room temperature vulcanized nitrile silicone rubber is poly β-nitrile ethyl methicone, room temperature vulcanized silicone rubber in addition to the light resistance, ozone resistance, moisture resistance, high and low temperature resistance and excellent electrical insulation properties of silicone rubber, the main characteristics are resistance to non-polar solvents such as aliphatic and aromatic solvents, its oil resistance is close to that of ordinary oil-resistant nitrile rubber, can be used as oil pollution parts and oil-resistant electronic components of sealing filling.
Room temperature vulcanized fluorosilicone rubber
Room temperature vulcanized fluorosilicone rubber is poly γ-trifluoropropyl methylsiloxane, which is mainly characterized by fuel oil resistance, solvent resistance and high temperature degradation resistance, as well as good extrusion performance. It is mainly used for the sealing and caulking of the overall fuel tank of supersonic aircraft, the bonding and fixing of fluorosilicone rubber gaskets and gaskets; the bonding of silicone rubber and fluorosilicone rubber, as well as fuel oil resistance in chemical engineering and general industry; Adhesion of solvent-resistant parts.
Room temperature vulcanized benzene brace silicone rubber
Room temperature vulcanized benzene silicone rubber is a silicone benzene (biphenyl) silicone polymer, which has the outstanding advantage of excellent resistance to high-energy rays. The test proves that after being irradiated with 1×109 roentgenium γ-ray or 1xl018 neutron/cm2, it can still maintain rubber elasticity, which is 10~15 times larger than room temperature vulcanized methyl silicone rubber and 5~10 times larger than room temperature vulcanized phenyl silicone rubber.
Room temperature vulcanized benzene support silicone rubber can be used in the atomic energy industry, nuclear power plants and aerospace as high temperature, radiation resistant adhesive sealing materials, as well as motor insulation protective layer.
Silicon sulfide
broadcast
edit
definition
Vulcanized silicone rubber is a new type of silicone elastomer, which is used to manufacture one-component and two-component sealants of dealcoholization, deacetic acid and deketone oxime. It can also be used as an electronic potting compound as an insulating material. Take advantage of the characteristics of 107 glue with good high and low temperature resistance.
characteristic
It can play a protective role in moisture-proof, anti-corrosion, shockproof and so on. Silicone rubber performance and stability parameters can be improved. After vulcanization, the vulcanized silicone rubber at room temperature has excellent anti-sticking properties, and the shrinkage rate is very small during vulcanization, so the vulcanized silicone rubber is particularly suitable for deep potting materials and has a fast vulcanization time.
apply
It is widely used as a potting and molding material. After being coated and potted with room temperature vulcanized silicone rubber for various electronic and electrical components, it is widely used in sealing in the automobile and machinery industries, seismic materials, rubber roller materials in the textile, plastic, and printing industries, and caulking sealing materials in the construction industry. At the same time, it can be used to make soft molds for casting epoxy resin, polyester resin, polystyrene, polyurethane, vinyl plastics, paraffin, low melting point alloys, etc. In addition, the high fidelity performance of two-component room-temperature vulcanized silicone rubber can be used to replicate a variety of exquisite patterns on cultural relics. [3]
RTV Silicone sealant
