Polyurethane tri-proof adhesive preparation method and application
With the rapid development of industrial technology, microelectronic devices have become an indispensable part of various electronic products, however, in the traditional way of fixing is often used in direct welding method. UV curing technology is widely used in coatings, adhesives, microelectronics, dental prosthetics and biomaterials. UV-curable tri-proof adhesive (UV tri-proof adhesive) for the UV-curable electronic coating (EMT), usually formulated from low-viscosity low-volatility resin, it can be used in selective spraying equipment, good water resistance, shock resistance, salt spray resistance, breakdown strength is also stronger than other tri-proof paint. Usually circuit board protection UV-curable tri-proof adhesive fast curing time of only tens of seconds, and UV-curable tri-proof adhesive is a solvent-free products, its components do not contain voc, to avoid exposure to component residues, fingerprints, dust and grease and other sources of contamination in the assembly of products.
However, the adhesion of the current UV-curable tri-proof adhesive on substrates such as pcb circuit boards still needs to be further improved.
Therefore, the development of a good adhesion, flexibility, fast curing and good flow properties, and make it moisture-proof, mold and salt spray resistance of polyurethane three-proof adhesive, can be used for electronic circuit board bonding, for social business and ecological environment are of great significance.
This polyurethane tri-proof adhesive has good adhesion, flexibility, fast curing and good flowability, and also has moisture-proof, mildew-proof and salt spray-proof properties, and this polyurethane tri-proof adhesive has good effect when applied to electronic circuit board bonding.
The preparation method of this polyurethane tri-proof adhesive, with light-curing resin, trimethylene cyclohexyl acrylate, methyl methacrylate and dipropylene glycol diacrylate as the base resin, gives the polyurethane tri-proof adhesive very good adhesion, improves the flexibility of the colloid by reasonably matching the polyethylene glycol 400 diacrylate, reasonably adding initiator to improve the cross-linking rate, greatly reducing the curing time, reasonably adding The leveling agent increases the flowing performance of the triple anti-collagen.
Preparation method and application of tri-proof adhesive
With the gradual shift to miniaturization, integration, multi-functional electronic products, as well as the diversity of the external environment, the reliability of electronic products has brought serious challenges, in order to make the core components of air conditioning – printed circuit board assembly (PCBA) from the erosion of the external environment, to ensure long-term operation of high reliability, home electronics widely used three anti-adhesive to protect the circuit board integrated circuits and components. Three anti-glue (also known as three anti paint, conformal coating), is coated in the printed circuit board has been soldered and inserted components of the protective coating. Its role is to make electronic devices from the erosion of the external harmful environment, such as dust, moisture, salt spray, chemicals, mold and other corrosion, with salt spray, moisture, mold and other properties.
At present, the existing technology is mostly used in the traditional solvent-based three-proof adhesive, which requires a long curing time (7 days), the subsequent manufacturing process and the overall production / shipping efficiency of the product has significant constraints. In particular, the use of solvent-based three-proof adhesive in the process of releasing a large number of VOCs, which will pollute the production site and the surrounding environment, affecting the health of production personnel. At the same time, solvent-based tri-proof adhesive in the curing of the formation of the coating consistency is relatively poor, and the phenomenon of bubbles, seriously affecting the protective effect.
This three-proof adhesive preparation method and application to solve the existing three-proof adhesive existing or poor protection performance, or curing efficiency is poor, or the application process will produce a large number of VOCs and other problems.
The present tri-proof adhesive composition, including reactive diluent, urethane acrylic resin and photoinitiator.
Acrylate modified silicone resin and its application in UV moisture dual-curing silicone tribo-proof paint
Silicone polymer materials have been widely researched and applied in aerospace, military, chemical, transportation, construction and other industries due to their unique composition and molecular structure with excellent resistance to high and low temperatures, weathering, aging, low surface tension and physiological inertia, and are gradually coming into daily life. It is worth noting that silicone resins play a particularly prominent role in the electronics industry. This is mainly attributed to the fact that functionalized products such as adhesives and coatings prepared from silicone resins have excellent bonding, insulation, moisture-proof, anti-leakage, shock-proof, dust-proof, anti-corrosion, anti-aging, corona resistance, etc. They can be used as encapsulation materials for electronic components, thus protecting circuit boards and related equipment from environmental erosion and improving the stability and life of electronic products.
However, traditional silicone materials are generally cured in the following ways: thermal radical curing by peroxide initiator-initiated polymerization of double-bonded groups; thermal addition curing by double-bonded groups with silicone hydrogen under the action of a platinum catalyst; moisture curing by reaction of alkoxy groups with moisture in the air. However, the above curing methods often require high temperatures or several hours or even up to several days to cure, which to a certain extent limits the application of silicone materials in some fields.
UV curing is a technique to obtain rapid cross-linking by triggering the rapid polymerization of unsaturated double bonds in monomers or oligomers under the irradiation of rays with a certain energy. As early as 2004 at the International Conference on Radiation Curing, UV curing technology was defined as an industrial technology with “5E” characteristics, namely efficient (efficient), enabling (adaptability), economical (economic), energy saving (energy saving), environmental friendly (environmentally friendly). environmental friendly (environmental friendly). Therefore, the technology has a very broad application prospect in the field of adhesives, coating and painting, electronic packaging and other industries. This provides a new technical idea for the rapid curing of silicone resins and their efficient industrialization. At present, according to the differences in curing groups, UV curing system can generally be divided into free radical curing system and cationic curing system. Currently commonly used UV curing materials are generally acrylate resins, cured in accordance with the free radical curing mechanism. Such resins have strong UV reactivity, can be adjusted according to different application conditions viscosity and hardness, has been a very mature UV curing materials.
Nevertheless, but the traditional acrylate UV curing resin still has the following defects: (1) although the traditional acrylate based resin has a very high UV reactivity, curing rate is very fast (generally seconds), but the inherent free radical polymerization mechanism of such groups makes it very sensitive to oxygen in the environment, the presence of oxygen will have a significant blocking effect on the (meth)acrylate groups, resulting in curing (2) Since the curing process of UV-curable resin system is initiated by UV light, the UV curing efficiency of the system will be limited by the shape, thickness, color, etc. of the cured object. For example, for curing objects with complex shapes, areas that cannot be directly irradiated by light and areas where shadows are formed will not be fully UV cured. (3) Such resins also have poor resistance to high and low temperatures, poor aging resistance and many other defects, it is difficult to meet the performance requirements of some fields. Therefore, the above problems are particularly prominent for UV-curable adhesives and three-proof varnishes used in bonding/encapsulation of electronic components.
Silicone resin three-proof paint has high and low temperature resistance, can be quickly UV cured, and through the two-stage moisture reaction can be achieved in the shadow area of light irradiation can not be further cured.
UV and moisture dual-curing three-proof paint preparation method
At present, with the further increase in the degree of intelligence of electronic products, the circuit board circuit integration is getting higher and higher. In particular, the PCB circuit with three-proof paint currently exists too thick film, resulting in pre-construction and post-processing process there is insufficient curing; poor fluidity leads to uneven coating and other problems, making the three-proof paint dust, moisture, salt spray and other characteristics of the decline in the service life of the circuit board shrinks too quickly. In this case, the three-proof paint on the circuit protection requirements are increasingly demanding, so it is extremely important to provide an ultra-low viscosity, multi-path curing, good flow, uniform paint film three-proof paint.
Most of the existing market circulation of three-proof paint has the following problems: ①, resin, monomer selection mismatch, dilution capacity is weak, resulting in the configuration of the three-proof paint viscosity is too large, inconvenient construction; ② initiator selection of a single type, and resin can not be fully cross-linked, poor adhesion, resulting in the use of three-proof paint is easy to fall off, can not play a protective role; ③ curing a single way, for hidden circuit boards, UV light curing is not sufficient, construction The process is prone to problems such as uncured, resulting in a reduction in the service life of the circuit board. How to solve the above technical problems is the object of research in the field of technical personnel.
The present technology provides an ultra-low viscosity, multi-path curing, good flow, uniform paint film UV and moisture dual-curing three-proof paint and preparation method.
The composition of each component is, acrylate, acrylic monomer, photoinitiator, defoamer, dehydrating agent, wetting agent, coupling agent; said photoinitiator is: 2-hydroxy-2-methyl-1-phenyl -1-propanone, methyl α-oxobenzeneacetate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and any three of 1-hydroxycyclohexyl phenyl ketone. This technology uses high matching resin and monomer preparation of ultra-low viscosity UV and moisture dual-curing three-proof paint, to solve the construction of inconvenience and other problems, combined with a variety of initiators for compounding, adapt to a wide range of ultraviolet wavelength, so that the resin fully cross-linked to improve adhesion.
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