Medical conductive pressure sensitive adhesive

Frequent replacement of disposable electrodes is required in electrocardiograms, electroencephalograms, defibrillation instruments, my electrometer, transcutaneous electrical nerve stimulation therapy, neuromuscular electrical stimulation therapy, and other medical examinations and electrotherapy.

The electrical conductivity of this electrode and its adhesion properties are directly related to the examination results. In addition, since the electrode is in direct contact with the skin, the material of the electrode is required to be non-irritating, non-cytotoxic, and non-sensitizing to the skin.

Acrylic pressure sensitive adhesive

At present, the disposable medical electrode is mainly composed of substrate carrier film, Ag/AgCl conductive paste printing layer, conductive pressure sensitive adhesive, and release film. Among them, the conductive pressure-sensitive adhesive is also referred to as conductive adhesive, which is mainly composed of acrylic conductive pressure-sensitive adhesive containing hydrophilic groups loaded with certain water and conductive electrolyte.

The existing acrylic conductive pressure-sensitive adhesive uses non-water-soluble acrylic ester, volatile, and easily causes toxic side effects; In order to reduce volatilization and residue, it is usually necessary to increase the recovery device and prolong the curing time, which increases the production cost and affects the production efficiency.

Chinese patent CN107163866A disclosed a medical UV curable water-based conductive pressure-sensitive adhesive, the conductive pressure-sensitive adhesive using hydroxypropyl acrylate, hydroxypropyl methacrylate, and other monomers to prepare medical conductive pressure-sensitive adhesive, although this monomer is water-soluble, its volatility is still large, processing and production inconvenience.

Moreover, such monomers have no ionic base and have no beneficial contribution to the conductivity of the conductive pressure-sensitive adhesive made, which requires electrolytes or monomers with ionic groups to provide. In addition, the Chinese patent CN107903838A discloses a kind of UV-curable conductive adhesive and its preparation method. The conductive adhesive uses 2-acrylamide – 2-methyl propyl sulfonic acid as the polymerization body to solve the volatilization and residual harm of non-water-soluble acrylate, and the monomer is anionic, which is beneficial to the conductive property of the prepared conductive adhesive. However, the conductive adhesive obtained from the process formula has weak adhesion and is easy to fall off when it is glued to the skin.

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Pressure sensitive adhesives that can be vulcanized by heat

Pressure-sensitive tapes that can be thermally vulcanized are known. Patent EP 877 069 A describes a pressure-sensitive adhesive sheet based on a thermovulcanized polyester rubber. The disadvantage is a specific aspect of the manufacturing operation: the polyester reaction is initiated with a liquid starting material. By gradually cross-linking the reaction, the polymer is formed only during the coating period.

This has the following disadvantage: the coating speed is limited because the reaction mixture coated on the stripped liner or the carrier material cannot be wound, or at least cannot be wound at a constant layer thickness, while it is still liquid or paste. Only solid polymer films can be wound with constant layer thickness. Therefore, the reaction product cannot be wound until the reaction mixture is solidified. The coating speed must be set to a correspondingly slow rate. Moreover, polyester rubber has the potential disadvantage of easy hydrolysis and splitting.

pressure sensitive adhesive

The rubber described in DE 38 30 895 A consists of at least two starting polymers chemically connected to each other by an ester group and at least one of which is unsaturated in the alene group.

The rubber has in principle disadvantages similar to the possible base elastomer of a pressure-sensitive tape that can be thermally vulcanized. The same applies to liquid or spreadable (spreadable) vulcanizable rubber mixtures described in EP 0 356 715 A, which are based on polyester polymers, at least one of which is unsaturated in the genus alene. Polybutadiene-polyurethane pressure sensitive adhesive is described in JP 59230076A.

Polybutadiene-polyols with 2.2-2.4 functionalities react with polyisocyanates at a NCO/OH ratio of 0.2-0.65 to form polyols with a molar mass of 5000 to 30000 and a functionalities of 2.2-2.4. The polyol was then mixed with polyisocyanate at a NCO/OH ratio of 0.6-1.0 and reacted accordingly to form the desired product. There is no indication of a base polymer that may be used as a pressure sensitive adhesive that can be thermally vulcanized, which will be prepared solvent-free in the mixing and coating operation.

For such use, the pressure-sensitive adhesive will have the disadvantages of being cross-linked initially and therefore unsuitable for coating operations, or being liquid at room temperature and therefore unsuitable as a base elastomer for coating operations where very low NCO/OH ratios are operated within the limits specified in the patent and therefore no cross-linking occurs.

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UV degumming pressure sensitive adhesive

UV photodesinking pressure-sensitive adhesive is also known as UV degumming adhesive, which refers to a class of pressure-sensitive adhesives that can reduce adhesion through UV photoexcitation. UV viscose has the characteristics of easy construction, high initial adhesion, and easy removal after UV viscose. UV adhesive can be used in semiconductor processing as a temporary holding and protective tape for wafer cutting.

It can also be used for temporary protection of appearance parts in the manufacturing process. It can also be used in flexible circuit boards to make transport tape. Its good adhesive relay can ensure that the flexible circuit board will not fall off in the process of nickelization gold, and it is easy to remove after unadhesive, which prevents the flexible circuit board from deformation caused by too much adhesive tape when removing the protective tape. It can also be used in the medical field, the ordinary medical tape is stuck on the skin for a long time, and the adhesive will gradually become bigger.

UV degumming pressure sensitive adhesive

For some areas where the skin is more fragile, removing the common medical tape will cause the skin to tear. Medical UV adhesives can be used to reduce adhesion through low doses of UV light, reducing the patient’s pain when the tape is removed. Compared to traditional protective films, UV adhesives are more adhesive in protection engineering and easier to remove after unbinding. Existing UV adhesives typically consist of pressure-sensitive adhesives, UV-polymerizable oligomers (also known as UV oligomers, or adhesives), and free radical-type photoinitiators.

Pressure-sensitive adhesive provides initial bonding. When UV light is irradiated, UV oligomers crosslinking under the action of free radical photoinitiator makes the overall modulus of the de viscose adhesive improve. In this way, the adhesive layer hardens and loses its adhesion.

However, the interaction between the pressure-sensitive adhesive and UV oligomer is usually only the molecular chain interaction when the existing de viscose composition is deviscose. Insufficient interaction between pressure-sensitive adhesive and UV oligomers often leads to the pressure-sensitive adhesive being unaffected by UV oligomers, resulting in local residual adhesive formation, insufficient viscosity reduction, or abnormal enlargement.

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Express logistics pressure sensitive adhesive

In the current rapid development of the social environment, logistics transportation, express and other industries inevitably use PE based materials of ordinary express bags and anti-counterfeiting express bags, at the same time, the application of environmental protection hot melt pressure sensitive adhesive in the express bag adhesion just greatly improve the production efficiency of this kind of industry.

acrylic pressure sensitive adhesive

The traditional hot-melt pressure-sensitive adhesive for express bags is mainly made by using SBC system, SBS or SIS rubber as the base material, and adding a certain proportion of naphthenic oil, viscosifying resin and antioxidant. On the basis of this technology, there are also public reports that emphasize the use of dissolved polystyrene butadiene rubber SSBR and liquid rubber to improve the SBC system, such as the Chinese patent CN 108410402 A; Or emphasizing the characteristics of low temperature lamination and high viscosity and using star SIS and polybutadiene to improve the SBC system, as shown in Chinese patent CN 106398606 A.

These traditional SBC system or improved SBC system of hot-melt pressure-sensitive adhesive in the use of ordinary express bags and anti-counterfeiting express bags, there is an inevitable problem: with the change of temperature after the express bag adhesion, hot-melt pressure-sensitive adhesive appears creep, which wrinkles the adhesive of the express bag, seriously affecting the appearance. This is acceptable in the ordinary express bag bonding, but it is unacceptable in the anti-counterfeiting express bag bonding.

Therefore, it is necessary to invent a kind of hot melt pressure sensitive adhesive with low creep and high viscosity to make up for the deficiency of the above two types of hot melt pressure sensitive adhesive, which is also a more perfect adhesive solution that the current consumption upgrade forces logistics, transportation and express industry to provide. The invention provides the following technical scheme: A hot melt pressure-sensitive adhesive for express logistics with low creep and high viscosity, the components include metallocene olefin polymers (25%-35%) by mass percentage, rubber-reinforced chain polymers (15%-25%), viscose resins (26%-35%), low molecular polyisobutene (8%-15%), naphthenic oil (5%-20%), and antioxidants (0.5-1.5%).

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Water-based multi-time movable pressure sensitive adhesive containing microcapsules

Pressure sensitive adhesive is a kind of adhesive which is sensitive to pressure. The pressure sensitive adhesive can form a relatively strong bonding force under a small force. The bonding force formed between the two surfaces is mainly van der Waals force and other polar forces.

Therefore, after the formation of the adhesive surface, the structure of the adhesive surface is mostly not destroyed, and its adhesion can be maintained for a relatively long time. Pressure sensitive adhesive products on the market are mainly divided into solvent – based and water-based two categories.

pressure sensitive adhesive

Solvent-based pressure sensitive adhesive still contains organic solvents (VOC) such as toluene, xylene and ethyl acetate after being prepared into terminal products, so it should not be used indoors or in places without ventilation. Water-based pressure sensitive adhesive is made of water as a solvent, without VOC and other harmful substances after the final product, can be used in a variety of occasions with special requirements for health and environmental protection.

Pressure sensitive adhesive can be divided into permanent adhesive, removable adhesive and multiple removable adhesive from the use of function. Permanent glue will be left on the paste surface after use, cleaning time-consuming and laborious, easy to destroy the original interface, so it can only be used once, containing solvent pressure sensitive glue will cause secondary pollution; Solvent-based or a few water-based removable adhesives are mostly two-component acrylic pressure sensitive adhesives, often limited to a specific interface or substrate, so its use is small, affecting the wide range of product popularity.

There are a few domestic acrylic water-based movable adhesive products, but there are generally poor glue cohesion, paste surface residual glue, poor stability, not compatible with a variety of substrates and different interfaces, and difficult to achieve multiple removable problems. A water-based multiple moveable pressure sensitive adhesive containing microcapsules and a preparation method thereof are required. By introducing the polymer with microcapsule structure and the multi-component star polymer, a water-based, environment-friendly, multiple removable, adhesive surface without residue, good cohesion, strong versatility of water-based multiple removable pressure sensitive adhesive was obtained.

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Selective hydrogenation catalyst, preparation of hydrogenated petroleum resin method of hydrogenated petroleum resin hot melt pressure sensitive adhesive

Using cyclopentadiene compounds as raw materials, petroleum resins can be obtained by thermal polymerization or cationic polymerization, and dicyclopentadiene petroleum resins are more common. Dicyclopentadiene petroleum resin is a light yellow to brown-yellow thermoplastic solid with a molecular weight between 300 and 3000. It can be used in the fields of road marking paint, adhesives, and rubber modification.

adhesive

However, dicyclopentadiene petroleum resin has a dark color, strong odor, and poor aging resistance, so it has been developed gradually. H-t-m e l t pressure-sensitive adhesive (HMPSA), which is prepared with adhesive resins such as dicyclopentadiene hydrotreating petroleum resin, is often used in disposable sanitary products and labeling.

In the process of preparing HMPSA, the compatibility between viscosifier resin and polymer elastomer is crucial. The better the compatibility between viscosifier resin and polymer elastomer, the greater the viscosity of HMPSA prepared. In the process of preparing HMPSA with dicyclopentadiene hydrogenated petroleum resin, it was found that the compatibility between dicyclopentadiene hydrogenated petroleum resin and polymer elastomer was not good, and the cohesion energy of dicyclopentadiene petroleum resin was low, the prepared HMPSA had low adhesion and stripping strength, and the application performance in the field of disposable sanitary products was poor. In order to solve the above problems, the researchers copolymerized aromatic hydrocarbons containing a benzene rings with dicyclopentadiene to introduce a benzene ring with high polarity into the resin.

However, in the existing preparation method of dicyclopentadiene hydrogenated petroleum resin, the benzene ring added is very easy to be saturated by simultaneous hydrogenation during the process of double bond saturation of resin hydrogenation. As a result, some benzene rings with higher polarity are saturated into six-membered rings with lower polarity, so the compatibility improvement degree of copolymerized hydrogen is limited, and most of them have strict requirements for raw materials, high cost of raw materials, poor effect and not suitable for large-scale continuous operation and other problems.

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Silicone pressure sensitive adhesive

Pressure sensitive adhesives are prepared by combining silicone elastomer materials with viscosifying resins, including silicone viscosifying resins. Such as US patents 5,237,082(Leir et al.),5,264,278(Mazurek et al.),5,264,278(Mazurek et al.),5,314,748(Mazurek et al.), and 5,514 ,730(Mazurek et al.).

acrylate copolymer adhesive

Silicone elastomer materials in pressure-sensitive adhesives have been prepared by polymerization of silicone compounds with end-alene unsaturated groups using actinic radiation (e.g. ultraviolet radiation) in the presence of conventional Norrish type 1 photoinitiators. Advantageously, the polymerization can occur in the absence of an organic solvent and/or in the presence of a thermal material such as a thermal substrate. Active controlled radical polymerization methods have been developed that allow the preparation of polymers with well-defined molecular weight, polydispersity, topology, composition, and microstructure.

These methods are based on the use of special polymerization media that temporarily and reversibly convert growing radicals into dormant and/or stable species. Reversible transformation is usually achieved by reversible inactivation or by reversible chain transfer.

Some methods involved in active controlled radical polymerization by reversible transformation include the iniferter method, the nitroxide mediated polymerization (NMP) method, the atomic transfer polymerization (ATRP) method, and the reversible addition and fracture (RAFT) method. The terms “initiated transfer terminator” and “photoinitiated transfer terminator” refer to molecules that may act as initiators, transfer agents, and terminators. In Otsu et al., Macromol.Chem.,Rapid Commun. , 3, 127-132 (1982) discussed various transfer-inducing terminators. The use of the compound p-xylene bis-(N, n-diethyl dithio-carbamate) (XDC) to form various acrylate-based block copolymers such as those described in European patent applications 0286376 A2(Otsu et al.) and 0349270 A2(Mahfuza et al.).

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Acrylic pressure sensitive adhesive for microwave door stickers

Ordinary microwave oven door paste is made of transparent polyester film with a thickness of 0.1mm coated with acrylic solvent pressure-sensitive adhesive after drying and releasing polyester film composite, the final die-cutting molding. The appearance requirements of microwave oven door stickers are transparent and clear, and there should be no scratches, bruises, bubbles, and other undesirable phenomena on the surface. The physical property index is 90° peeling strength ≥10N/25mm. Temperature resistance 180℃ (the surface coated with solvent pressure sensitive adhesive polyester film on the microwave door plate in 180℃ environment after heating for 30 minutes, the appearance of the door paste shall not turn yellow, or warped, clarity shall not weaken, distance 1 foot can see the word typeface 4).

pressure sensitive adhesive

High-temperature microwave oven door sticker should be able to withstand 210℃. Microwave oven door paste technical requirements whether appearance or physical indicators single look is not difficult to do, there are a lot of adhesives on the market that can meet the requirements, but comprehending all indicators to meet the requirements is very difficult, with clarity, peel strength and can not reach, vice versa. Although the existing adhesive formula can meet the above basic requirements, the shrinkage rate is large, and can only withstand the temperature of 180℃, only suitable for ordinary microwave ovens, 210℃ baking door paste will still occur warping, fuzzy, and peeling strength reduction phenomenon.

This paper provides a preparation method for acrylic pressure-sensitive adhesive for microwave door pasting. The steps include: (1) adding the viscous monomer, cohesive monomer, modified monomer, crosslinking agent, solvent, and emulsifier into the reaction reactor, stirring and heating up to 85±2℃, holding temperature 1.5 h; (2) Cool the reactor to 75±2℃, then add 1/3 weight part of the initiator, heating reaction for 3-6h, three times continue to add the remaining 2/3 weight part of the initiator, each drop interval time is 0.5 h, reaction 1-2h after dropping, then reduce the temperature to 60℃; (3) Pour defoaming agent, leveling agent and wetting agent into the system of step (2), stir for 30-60min, and then cool down to 40 ℃ for filtration to obtain the acrylic pressure sensitive adhesive.

Beneficial effects: The acrylic pressure-sensitive adhesive for microwave oven door paste prepared by the invention can maintain the basic performance and at the same time make the product have good shrinkage, meet the appearance requirements of all the polyester film door paste for microwave oven, and the rear door paste will not warping, fuzzy, peeling strength reduction and other phenomena after baking at 210℃, so it is very suitable for high-temperature microwave oven such as barbecue microwave oven.

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Optical pressure sensitive adhesive for vehicle display

With the booming development of the on-board display industry, the original contact screen (TP) and display module (LCM) because of the iron frame, optical pressure sensitive glue (OCA) can not do more than 500μm thickness, the entire industry uses basic water glue to fill, with the iron frame gradually eliminated, the display structure becomes thinner, optical pressure sensitive adhesives with thickness between 150μm and 350μm are gradually being used in the market.

Optical pressure sensitive adhesive for vehicle display

Then the optical pressure-sensitive adhesive that plays the filling and bonding role in the vehicle display is particularly important. Conventional optical pressure-sensitive adhesive formulations use raw materials that use prepolymers containing double bonds or long molecular chains of acrylate polymers, adding initiators, acrylate monomers, antioxidants, leveling agents, etc., in accordance with a certain proportion to mix into optical pressure-sensitive adhesive glue.

The glue is coated between the release film and then cured to get the finished product. Filling of this OCA formula even if you can do a large, it is difficult to get good filling on the vehicle, because the better the filling, the softer the colloidal properties, then the corresponding adhesion and reliability will decline, assuming that the soft monomer is placed too much, then 105℃/ 1000H of this relatively strict reliability test will appear bubbles and other bad problems.

Therefore, the filling capacity of common onboard optical pressure-sensitive adhesives on the market is only about 20% (200μm optical pressure-sensitive adhesive can be used in ink cover glass below 40μm). One purpose is to provide an optical pressure sensitive adhesive for on-board display, in order to solve the existing technology of optical pressure sensitive adhesive used on the vehicle is difficult to get a good filling or very good filling, but poor adhesion and reliability. The invention uses resinous polymer and acrylic monomer, photoinitiator, and leveling agent to mix while ensuring reliability, greatly improving the filling and adhesion of the product.

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Low refractive index optical pressure sensitive adhesive needs to be developed

Optical pressure sensitive adhesive (OCA) is widely used in the field of optical display, used to connect display module, glass cover plate, plastic cover plate, touch screen and other display units, as its indispensable key material, OCA optical adhesive is more and more widely used. OCA optical adhesive in the display field is generally used for the connection of display Windows and display modules (LCD and OLED).

pressure sensitive acrylate adhesive

In some applications, the OCA optical adhesive needed for connection has a low refractive index, which can reduce the reflection of external strong light, so that the display can still display clearly in the sun or strong light. The refractive index of the ordinary OCA optical glue is generally about 1.47, and the refractive index of the display window material glass (1.5) is close, when in the sun or strong light, the outside light through the screen and reflected back, will cause interference to the screen display light, resulting in the screen picture is not clear.

We need to provide a low refractive index optical pressure sensitive adhesive. In order to solve the problem that the refractive index of traditional OCA optical adhesive is close to that of the display window material glass in the existing technology, when in sunlight or strong light, the outside light will be reflected back through the screen and cause interference to the light emitted by the screen display, resulting in unclear screen picture display.

An optical pressure-sensitive adhesive with a low refractive index was obtained by using a fluorinated acrylic polymer with a low refractive index, and under the combined action of diluent monomer, photoinitiator, antioxidant, and stabilizer. Another purpose is to provide the preparation method of low refractive index optical pressure sensitive adhesive as described above. Fluorine acrylate polymer, diluent monomer, stabilizer, antioxidant, and photoinitiator are mixed and mixed, and ultraviolet irradiation is used to cure, to obtain optical pressure-sensitive adhesive. This method is simple to operate and can be obtained by controlling the wavelength of ultraviolet light with low refractive index optical pressure sensitive adhesive.

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