Waterborne PP adhesion promoter adhesion increase method

Learned, waterborne PP adhesion promoter and the substrate can be combined by mechanical, physical adsorption (including wetting), formation of hydrogen bonds and bonds, diffusion effect such as each other together, its adhesion is good or bad depends on the degree of the combination of coating and substrate, there are many kinds of way to increase the adhesion (such as with a variety of resin, handling of the substrate, adding adhesion accelerator, etc.), add adhesion promoter is a simple and efficient method.
On PP substrate way to increase the adhesion can be directly spray on the surface of a thin and uniform layer of chlorinated polypropylene resin, its theory is the same material through the miscibility, winding and HCL free acid of PP substrate "erosion" and play a role, can increase the surface of the substrate, to make the group of paint to "catch" to live.
Methods of PE substrate: most by corona treatment (due to other processing method has defended, such as flame, chromate treatment, etc.).But corona equipment is very expensive, it makes little sense to promote.Suggestion: use fluorocarbon flow ping agent on the PE substrate wetting.Appropriate heated to a temperature of about 80 ℃, the paint application polyamide resin and polyurethane.Add some appropriate split darma resin.Of course there are other ways: with fluorocarbon class of wetting agent wetting at the same time with something such as coupling agent.Make the PE substrate above the polar groups, etc.The adhesive agent for PP substrate has very mature, for PE material end remains to be further discussed.

(source:http://www.ac-chem.net/news/waterborne-pp-adhesion-promoter-bb49.html)

N propyl organism crosslinking agent

N propyl organism crosslinking agent (XR - 100) with carboxyl reaction at room temperature, so the polyfunctional degrees n propyl organism crosslinking agent is good crosslinking agent containing carboxyl system, it can with water and many organic solvents miscibility, and also can response under dry state.N propyl organism the dosage of the cross-linking agent is usually acrylic or polyurethane solid content of 1% - 1%, room temperature curing, can also be heating oven curing.After n propyl organism crosslinker crosslinked coating can significantly improve the coating of water resistance, chemical resistance, resistance to wet and dry grinding, the surface of the viscous resistance, fastness of coating and improve on the special substrate adhesion, etc.
N propyl organism crosslinking agent can improve the water resistance of waterborne wood paint coating, friction resistance, adhesion and resistance to chemical character improve leather coating dry wet rubbing fastness and resistance to chemical quality improvement of textile printing mucilage to atone effect element on the surface of the wash and the viscosity increase and the cohesion of water-based adhesive protective film on the base material of glue solution to improve water resistance of water-based ink and wet rub resistance, the optimum printing sex coating increases the resistance to water and water-based sealant reinforced cement with cohesion in the vinyl coating can reduce the migration of plasticizer, improve the fouling resistance in waterborne industrial  coatings can improve the water resistance, viscous resistance, resistant to alcohol

(source:http://www.ac-chem.net/news/n-propyl-organism-crosslinking-agent-a8f3.html)

Discuss about coating paint adhesion promoter

Between coating and substrate can be combined by mechanical, physical adsorption (including wetting), the formation of hydrogen bonds and bonds, diffusion effect such as each other together, its adhesion is good or bad depends on the degree of the combination of coating and substrate, there are many kinds of way to increase the adhesion (such as with a variety of resin, the processing of the substrate, adding adhesion accelerator, etc.), add adhesion promoter is a simple and efficient method.Adhesion on ordinary book has introduced a lot of books, now let me talk to you to explore the high-density polyolefin plastic PE, PP and nylon PA way to increase the adhesion, and on how to increase the adhesion to glass:
One. Polyolefin plastic substrate PE, PP briefing:
PE and PP is inert organic material, its itself does not have polar groups and surface energy is low.The surface tension in 1.0 * 10 ˉ & sup2;Dagen below, or less, so ordinary paint doesn't wetting its substrate, not to mention other chemical bonds can play a role.
1. Increases on PP substrate adhesion method can be directly spray on the surface of a thin and uniform layer of chlorinated polypropylene resin, its theory is the same material through the miscibility, winding and HCL free acid of PP substrate "erosion" and play a role, can increase the surface of the substrate, to make the group of paint to "catch" to live.
2. The method of PE substrate: most by corona treatment (for other treatment methods have defended side, such as flame, chromate treatment, etc.).But corona equipment is very expensive, it makes little sense to promote.Suggestion: use fluorocarbon flow ping agent on the PE substrate wetting.Appropriate heated to a temperature of about 80 ℃, the paint application polyamide resin and polyurethane.Add some appropriate split darma resin.Of course there are other ways: with fluorocarbon class of wetting agent wetting at the same time with something such as coupling agent.Make the PE substrate above the polar groups, etc.The adhesive agent for PP substrate has very mature, for PE material end remains to be further discussed.
Two. PA (nylon) substrate to improve adhesion method is to spray a thin and uniform layer of polyamide resin film, or directly with polyamide resin as main resin add some adhesion promoter directly spray can.
Three. Discussion on the adhesion of glass substrate:
Glass substrate is a kind of hydrophilic inorganic substrate.In the general case, the glass is easy to combine with moisture in the air.Even in the dry room can also be seen under a microscope on the glass surface with a thin layer of water spray layer.In wet weather, could be seen with the naked eye.Therefore the paint in the humidity environment construction, the glass substrate is not firm, because there is a layer of water blocking paint group, grasped the glass, even in the long time can capture the glass will be off the paint.So the best way to attach is can penetrate fog layer, with groups hold glass, known as the hydrophilic, and wrapped with paint itself adhesion (That is lipophilicity).
At present is proved with epoxy and amino adhesion promoter can do more than two points.And, of course, many with both epoxy group and amino group and other groups, such as ether bond, etc.) or more groups of coupling agent.Above the adhesion promoter can increase the adhesion to glass well.If the customer requirements more stringent adhesion, can be sprayed on the glass substrate or concentration of one for more than 5% with groups of adhesion promoter and then add 1-2% of total amount of additives to paint adhesion.

(source:http://www.ac-chem.net/news/adhesion-promoter-a85a.html)

Application of crosslinking agent DCP

Crosslinking agent DCP as polyethylene (PE), ethylene - vinyl acetate copolymer (EVA foam), chlorinated polyethylene (CPE), EPDM rubber (EPDM), chlorosulfonated polyethylene, four fluorine rubber (TP-2), saturated hydrogenated nitrile (HNBR), silicone rubber, rubber and plastic crosslinking agent. Under the condition of the same crosslinking effect, adding amount of about two-thirds of DCP.And made products in the process of operation without irritating smell.Especially suitable for indoor soft line of crosslinking and EVA foam insulation products, such as air conditioning use rubber sets of cables, EVA foam toys.Also can be used as PP JiangXieJi.Usage: can be used in adding rubber during mixing.Recommended storage temperature 38 ℃, crosslinking agent DCP non-perishable.Transportation should avoid exposure and intense shock.Avoid heat, it is strictly prohibited during storage with acid, reducing agent, etc.

(source:http://www.ac-chem.net/news/crosslinking-agent-87-a4fe.html)

Coating adhesion promoter

Coating adhesion promoter is a kind of special resin modified with silane coupling agent, the appearance is light yellow transparent liquid, not only for general metal surface (tin, steel, cast iron, aluminum alloy, electroplating) has an excellent effect of trivial, but for some special metal surface (e.g., copper), has a very good the effect, can improve the ductility of coating film and impact resistance, high temperature rapid baking, coating film with excellent weatherability.
The performance characteristics of coating adhesion promoter is as follows:
1) coating adhesion promoter is an exclusively for paint primer or one-time coating paint using the paint additives, to improve on the surface of metal as a sex, for some difficult adhesion of metal, also can provide good adhesion;
(2) the coating with adhesion promoter can improve coating on the surface of metal as a sex, so as to improve the ductility of coating film and the resistance to impact, and the adhesion between the layers of the coating has excellent effect;
(3) coating with adhesion promoter shall not affect the coating of storage and the weatherability of the coating;
(4) coating with adhesion promoter can be resistant to more than 280 ℃ high temperature baking, high temperature baking discoloration rapidly.

(source:http://www.ac-chem.net/news/coating-adhesion-promoter-89c4.html)

The influence about curing agent and silane coupling agent on the properties of organic silicone coating

By controlling the organic silicone coating formula of the content of curing agent and silane coupling agent, study their elastic modulus, hardness of coating materials, hydrophobicity, and the effect of water absorption and water immersion resistant performance.Results show that after the curing agent content is more than 4%, with the increase of content of curing agent, coating the elastic modulus decreased, shaw hardness increases, bibulous rate is increasing;The increase of the content of silane coupling agent, elastic modulus and the absorption of the organic silicone coating increase, but shaw hardness and water contact Angle decreased.When adding 6% curing agent coating the elastic modulus of water is the most sensitive.Containing 5% curing agent and 8% content of silane coupling agent of organic silicone coating significantly lower stability in the water.Amount of curing agent added can lead to high silica chain  crosslinking degree increase, dense mesh structure change, increase the coating hardness, go against the antifouling performance of the coating;Excessive amount of silane coupling agent is added will lead to coating on the surface of the hydrophilic group increased, the water contact Angle decreased, Marine bacteria increase.

(source:http://www.ac-chem.net/news/silane-coupling-agent-73-9459.html)

Mechanism of silane coupling agent in polymer matrix composites

(1) the chemical bond theory, the silane coupling agent contains two kinds of different chemical functional groups, one end of which can react with inorganic materials, such as glass fiber, silicate, metal oxide and other surface.
(2) surface infiltration theory that silane coupling agent increases the surface tension of glass fiber and other inorganic materials, even so that it is greater than the surface tension of resin matrix, which is in favor of the resin in the inorganic surface infiltration and expansion, improvement in the resin of inorganic enhanced the wettability, the resin and inorganic reinforcing better materials bonded together.
(3) deformation layer theory, that the silane coupling agent in the interface is plastic, it can form a larger than 10 nm flexible deformation layer at the interface, the deformation layer has destroyed self healing ability, not only can the interfacial relaxation prestressed, and to prevent the crack extension, so it can improve the interface bonding strength.
(4) constrained layer theory, it is believed that there is a boundary zone between the high modulus and low modulus of composite materials, and the silane coupling agent is a part of the composite material. Silane coupling agent can not only bonded with the inorganic surface, but also can with reaction resin groups to the polymer "tight beam at the interface. When the modulus of the interface zone is between the inorganic reinforcing material and the resin, the stress can be transmitted uniformly.
(5) reversible hydrolysis theory, which is considered to have the water in the presence of the silane coupling agent and the glass fiber by the stress and the role of the fracture, but can be a reversible re healing. In this way, the rigid region (which is formed by the coupling agent and silane coupling agent) is also allowed to be relaxed, and the chemical bond theory, the constraint layer theory and the deformation layer theory are also available. This mechanism not only can explain the mechanism of interfacial coupling, but also shows the effect of the relaxation stress and the effect of anti - water - protection surface.
Inorganic pigments and fillers in coating liquid organic phase dispersion can be divided into wetting, depolymerization and stabilization (Kang Xuning) 3 stages. Because of these inorganic pigments and fillers, the surface is easy to adsorb on the surface of water, so the hydrophobic material is difficult to be wetted and dispersed. With silane coupling agent of inorganic pigments and fillers were pre treatment (surface modification), silane will replace pigment or filler on the surface of the water, coated particles and the R groups outward, become lipophilic, hydrophobic, and easy to be base material wetting. After wetting, the base material molecules are inserted into the inorganic pigment or filler particles, which separates them, so that they can disperse stably and prevent the precipitation and agglomeration. After treatment with silane coupling agent, inorganic pigment and filler surface reduce the structural function of the coating, so that the viscosity of the coating is greatly reduced, and the added amount of pigment and filler can not affect the flow.

(source:http://www.ac-chem.net/news/silane-coupling-agent-16-8543.html)

Coupling agent

Coupling agent is a kind of material with gender structure, it is a part of molecular groups can react with chemical groups on the surface of the inorganic matter, form a strong bond, another part of the group has the nature of organic matter, can react with organic molecules or physical wound, and the nature of the two kinds of different material firmly together.This makes sources, the price is cheap or specific performance inorganic as filling agent and strengthening agent use of plastic, not only can reduce the cost of plastic, and gives products other valuable performance, such as improve the mechanical properties, dimension stability, etc., to expand the application range of the plastic.
There are many kinds of coupling agent, the commonly used have titanate and silane, etc.Titanate coupling agent molecules contains an oxygen and three long chain alkanes molecular structure units, when the coupling agent and powder filler, alkoxy gain packing on the surface of the proton and the protons from the packing of bound water, including water of crystallization, chemical adsorption and physical adsorption of water, water to form a chemical bond, the filler coated on the surface of coupling agent molecules.And coupling agent on the other side of the molecular structure of three long chain unit with chemical crosslinking polymer molecules or physical wound, eventually combine inorganic fillers and polymer is very good, and improved the tensile strength, elongation and impact strength.At the same time, the effect of coupling agent can reduce the surface of the packing, improve the ability of filler dispersed in the resin, reduces the viscosity of filling system, increase the filling amount, reduced the mechanical wear and tear, saving power consumption, and also reduces the cost.

(source:http://www.ac-chem.net/news/coupling-agent-a1a4.html)

Epoxy silane

Waterborne epoxy silane is A kind of nanometer zinc rich epoxy silane coating, with two components, its formula is characterized by: with all components is 100%, the weight of the following for each component weight ratio: A component: 800 ~ 1000 mesh nanometer zinc powder 65% ~ 80%, the emulsion type epoxy resin 8% ~ 25%, 0.1% ~ 5% ethanol, deionization water 0.5% ~ 5%, thickener 0.1% ~ 1%, the heavy dose of 0.1% ~ 3%;B component: silane portfolio: [double a silicon alkyl amino silane, vinyl silane] 1.5% ~ 5%, and the combination of these two kinds of silane distribution ratio between 0.15 ~ 0.30, and 3% ~ 8% curing agent.
Study found that the epoxy silane after pre emulsion can be compatible with aqueous polyurethane, after modification of aqueous system can be stable for a long time and not gel, effective storage period more than 3 months.With the increase of dosage of epoxy silane, gradually increased the tensile strength of the coating and extension first to continue to fall, after a slight increase, bibulous rate dropped significantly, to improve the bonding strength obviously.

(source:http://www.ac-chem.net/news/epoxy-silane-b944.html)

Silane crosslinking

Silane crosslinking is introduced through silane coupling agent in the polyethylene, increase the intensity of the polyethylene, aging resistance and other characteristics.
Method of silane crosslinked polyethylene technology since the 60 s was got rapid progress, won a wide application.Silane crosslinked polyethylene in the industry now there are three main kinds of technological methods: two steps process (also called SioplasE), one-step production process (also called MonosilR) and vinyl silane copolymers process, including vinyl silane copolymers technology combines two steps, and many advantages of the one-step method, has more advantages, but, in the process of three kinds of crosslinking reaction is through the blend with silane alcohol condensation catalyst of silane modified polyethylene soak in warm water or water vapor, crosslinking needed moisture diffusion came in from the outside world.Due to the hydrophilic polyethylene, water in polyethylene, diffusion is slow, the crosslinking is very slow, and the products of the wall is thicker, the longer the crosslinking time.For example, in 80 ℃ warm water crosslinking, to achieve the same degree of crosslinking, 8 mm thick sheet should be 120 h, 15 mm thick sheet will be expected to 260 h, 22 mm thick sheet should be 1000 h.The above data is crosslinking of silane grafted PE speed data, vinyl silane crosslinking of copolymer faster than crosslinking of silane grafted PE speed lower than 3 ~ 4 times.This to the industrialized production of the silane crosslinked polyethylene caused great inconvenience, so how to solve the problem of slow crosslinking became a big problem in the silane crosslinking technology.

(source:http://www.ac-chem.net/news/crosslinking-9078.html)

Definition of silane

Silane is compound with silicon and hydrogen, is the floorboard of a series of compounds, including silane silane (SiH4) and b (Si2H6) and some more advanced silicon hydrogen compounds.The most used is silicane.Generally the silican do silane for short.
Silane as a source of silicon components of gas, can be used in the manufacture of high purity polycrystalline silicon, monocrystalline silicon, microcrystalline  silicon and amorphous silicon, silicon nitride, silicon oxide, heterogeneous silicon, all kinds of metal silicides.Because of its high purity and can achieve fine control, has become many other important special gas silicon source cannot be replaced.Silane is widely used in microelectronics, optoelectronics industry, used in the manufacture of solar cells and flat panel display, glass and steel plating, and is by far the world's only large-scale production of granular high purity silicon intermediate.Silane high-tech applications continues to appear, including used in the manufacture of advanced ceramics, composite materials, functional materials, biological materials, high energy material and so on, as many new technologies, new materials, the basis of the new device.The silane and is famous for its characteristic of spontaneous combustion and explosive.Spontaneous ignition of the silane has a very wide scope and strong burning energy, determines its gas is a kind of high risk.

(source:http://www.ac-chem.net/news/definition-of-silane-ac05.html)

The rubber crosslink structure

Through the branched chain link between rubber macromolecule chain into a three-dimensional space net type macromolecule, forming crosslink structure. Crosslinking key type and crosslink density is the most important parameters in the crosslinking structure, respectively has the structure of crosslinked key and junction in what density distribution between the molecular chain of rubber.Crosslinked rubber after various physical properties have larger change, which is the most significant performance affected by crosslinking density modulus and the hardness, because of the crosslinking of chain and chain sliding between the junction between the inhibition of polymer chain, modulus and hardness increased with the increase of crosslinking density increased;Crosslinking density and tensile strength and tear strength relationship is relatively complex, the scope of a certain degree of crosslinking, with a peak performance.Greatly influenced by crosslinking key type of fatigue resistance and heat oxygen aging performance.Due to the effect of fracture rearrangement of the sulfur exist many keys, contains a lot of sulfur vulcanized rubber network key fatigue resistance performance is good, and the key to higher carbon carbon to improve heat vulcanized rubber crosslinking key oxygen aging performance.

(source:http://www.ac-chem.net/news/the-rubber-crosslink-structure-8ab5.html)

Biological basis of crosslinking agent

Bayer materials science and technology (BMS) recently told a news conference has developed the first biological base polyurethane crosslinking agent.
Company says it cyclopentane diisocyanate (PDI) is a new isocyanate carbon content 70%.Coatings, adhesives, special goods business executives and BMS executive committee members, Daniel, Meyer said the company recent innovations include the world's leading as coating and adhesive curing agent of PDI derivatives.
Meyer told reporters and industry experts company plans in 2015 will be the first of April PDI foundation of product release in the city, and in 2016 began to up to 20000 tons/year, enough to cover 20 million vehicles) capacity for commercial manufacturing.He said compared with the existing two-component polyurethane coating, the paint material processing rate of 30% faster.In the medium term, is likely to be suitable for mixed plastics, composite materials and the underlying metal coating.
The innovation is BMS and francois hoff institute in Germany and German machinery equipment manufacturers DURR cooperation achievements.Innovation cooperation conforms to the BMS to develop new products strategy, Meyer said: "our goal is to combine in our partner on the value chain and its technical reference as early as possible to our research and development work, to ensure that our market customer  success. In addition we will provide more and more materials and solutions."

(source:http://www.ac-chem.net/news/crosslinking-agent-91-ba85.html)

Using ratio of crosslinking agent

When using crosslinking agent, should avoid to add acid packing, also be careful when adding antioxidants and other aromatic oil additives on crosslinking effects will have bad influence, it is important to note that.About the use of the crosslinking agent ratio has eight pay attention to the point.
First, epoxy resin can be through based on acids, amines, amino resin, isocyanate, phenolic resin, such as, cold & heat curing crosslinking system;
Second, the amino resin can through based on isocyanate, carboxylic acid or anhydride, epoxy resin, phenolic resin, such as, cold & heat curing crosslinking system;
Third, can be based on acids, phenolic resin, epoxy resin and isocyanate, carries on the cold & hot crosslinking curing system;
Fourth, can be based on alkyd resin acids, amines, amino resin, isocyanate, phenolic resin, peroxide, light initiator, etc., for cold & hot crosslinking curing system;
Fifth, the acrylic resin can be based on amine, amino resin, epoxy resin, acrylic acid ester, phenolic resin, free radicals, such as for cold & hot crosslinking curing system;
Six, polyethylene can be based on peroxide, silane crosslinking, including alcohol, electron beam
Seven, regular elastomer can be based on sulphur, peroxide, acrylic acid ester, etc, for cold & hot crosslinking curing system;
Eight, special elastomer can be based on a metal oxide, silicon alkoxide, resin, amine, cold & hot crosslinking curing system.

(source:http://www.ac-chem.net/news/crosslinking-agent-22-b1da.html)

The nature of crosslinking agent

Crosslinking agent is a kind of can plays a role of bridge between the linear molecule, allowing multiple linear molecules mutual couplet net structure of bonding material.Promote or adjustment between polymer molecular chain covalent bond or electrovalent bond formation of the material.Crosslinking agent in different industries have different name, such as: used in rubber industry is called "vulcanizing agent";In the plastic industry known as "curing agent, curing agent, curing agent;In adhesive and coating industry known as "agent" and "curing agent", etc.Despite the difference in the above address, but reflects the chemical properties and mechanism of are the same.
Often is material containing multiple functional groups in the molecule, such as organic dibasic acid, polyol, etc;Compounds or molecules contains more unsaturated double bond, such as divinylbenzene and diisocyanate, N, N - methylene double acrylamide (MBA), etc.But with monomer feeding, polycondensation (or aggregate) to a certain degree of crosslinking, make the product into insoluble cross-linked polymer;Also can keep a certain number of functional groups in linear molecules (or double bond) and then add certain substances to crosslinking, such as the curing of phenolic resin and rubber vulcanization, etc.

(source:http://www.ac-chem.net/news/crosslinking-agent-28-832c.html)

Mechanism of coupling agent

Since the 1960s, scientists study the mechanism of coupling agent. Has made great progress, although not yet a consensus, but explained by chemical bond theory has been confirmed by a large number of experiments. R-Si-OR the type of coupling agent of different end group can react with polymers and fiber respectively to bond.By connecting two phase of the chemical bonds of interfacial bonding to improve.Tesla's research shows that deposition on the surface of the glass fiber, coupling agent usually contains components of physical and chemical adsorption of non-uniform layers, rinse with cold water to wash it by hydrogen bonding connection part of the coupling agent, wash with hot water can wash away with silica and the key connection body, at the end of the molecular layer, fiber with multiple key silica and silane coupling agent combined with very strong, it plays a main role to improve the interface bonding strength, and physical adsorption of the components is ineffective or even harmful.So the concentration of the coupling agent on the interface bonding can also have an impact, such as glass fiber in different concentrations of KH550 (gamma - ammonia propyl triethoxy silane) soaked in the solution after 10 min made sample, test results show that the coupling agent content was 0.4% ~ 0.4% (mass fraction) within the scope of the effect is best, in 8% of high content in the solution treatment effect is the worst.When coupling agent concentration is too low, the glass fiber on the adsorption capacity is insufficient, the concentration is too high adsorption in silane is arranged on the surface of the fiber mixed and disorderly, the corresponding physical adsorption layer thickening, unfavorable to interface bonding.

(source:http://www.ac-chem.net/news/mechanism-of-coupling-agent-8168.html)

Biological molecules crosslinking theory significance

The natural crosslinking of biological molecules is a kind of natural movement, it with other material movement with the same side.In nature, all kinds of inorganic always exists in the form of relatively stable, the stable forms like celestial body movement, is to follow certain laws of nature after a long interaction and evolution into some sort of balance and stability of a state.In this state and universality of phenomenon shows that various substances have themselves and the environment balance and stability of a kind of trend, biological molecules of natural crosslinking is a reflection of this trend in organic biology.Each organism is a complex chemical system, system of various biological molecules contain a large number of chemically active groups, is a kind of unstable factors, they must interact with chemical balance and stability, and this makes between itself and the molecular biological molecules progressive natural crosslinking, this natural crosslinking is biological molecules tend to chemical equilibrium and stability of a natural change, is a form of physical exercise, in the process of the movement, the biological activities of various kinds of biological molecules is also accompanied by a gradual change between the molecules and molecular structure change, so as to show the cell differentiation,  biological aging phenomenon and law and a series of phenotypic change.Molecular cross-linking is one of the important chemical nature in the process of life change, its nature synergy with other involved in the whole process of life, form a complete system of life science.According to this principle, drugs could be developed and design experiments to explore life senescence as well as the basic method for prevention and treatment of some diseases.While under the condition of  existing in molecular crosslinking methods to artificially change the sequence of gene inactivation to reshape the creature also is very difficult, but with a certain method to alter the biological phenotype and prevention, treatment of certain diseases or predictable;Although under physiological capacity in the existing scientific level limit of biological molecules cross-linked to a certain degree is impossible, but with slow natural crosslinking to slow the speed of aging is feasible and promising;Laboratory diagnosis, we can detect the molecular  biological tissue crosslinking degree to calculate the biological age of biological tissue.Therefore, we think it is necessary to study on this subject use of advanced technology, the necessary scientific experiments, in order to establish a complete earlier theoretical system to make it to the direction of more accurate and more complete and eventually service to humans.

(source:http://www.ac-chem.net/news/biological-molecules-crosslinking-theory-significance-91aa.html)

Chemical modification of silane coupling agent

Silane coupling agent is made from silicon chloroform (HSiCl3) and unsaturated olefin with reactive groups under the platinum chlorate catalytic addition, then through alcoholysis. Quartz powder or other surface chemical modification of silica powder mainly using silane coupling agent, amino, epoxy group, including methyl allyl trimethyl, and vinyl silane coupling agent. - RO functional groups of the silane coupling agent can be in the water (including the packing surface adsorption of free water) hydrolysis to produce silanol group, a group that can be combined with SiO2 for chemical or combined with the original silicon ether glycol is an organic whole, become a homogeneous system. Like this, is to remove the moisture on the surface of the SiO2, and its oxygen atoms to form silicon ether bond, so that the silane coupling agent on the other side of the carried by the polymer and the polymer has the very good affinity of organic functional groups -R' covered tightly in quartz or silicon dioxide particles surface, form covering film with reaction activity.

(source:http://www.ac-chem.net/news/chemical-modification-of-silane-coupling-agent-8c94.html)

The application of silane coupling agent

Silane coupling agent of different plastics and filler system coupling effect is different. Commonly used, for example, three different stearic acid isopropyl ester, acyl titanium for calcium carbonate filled polypropylene, polyethylene, polystyrene can significantly improve the impact resistance, and the glass fiber reinforced polyester or epoxy resin, chooses gamma - methyl acryloyl need oxygen radicals propyl silane, three oxygen radicals can significantly improve the mechanical strength. Therefore, we should fully consider and main use resin, filling system, to select the best coupling agent.In order to produce the best effect selected coupling agent, still should according to certain operating conditions for filling agent processing.Usually, according to the solubility and stability of the coupling agent, the mixture solution or the solution of methanol, ethanol, acetone, etc, under proper temperature mixed with inorganic filler, join other additives in succession again, to ensure that coupling agent on the surface of the fillers, uniform distribution, to avoid interference between additive.Ester titanate coupling agent should avoid as far as possible with plastic additives and surface activity, so as not to interfere with the coupling reaction. At the same time, most titanate can occur in different degrees and esters plasticizer of ester exchange reaction, therefore, esters plasticizer in coupling agent and the synthetic resin and filler mix and coupling effects to join.Ester titanate coupling agent and silane coupling agent and can produce synergies.

(source:http://www.ac-chem.net/news/the-application-of-silane-coupling-agent-60-88b9.html)

Theory of action of silane coupling agent

The mechanism of silane coupling agent in polymer matrix composites is mainly the following theory:
(1) the chemical bonding theory that silane coupling agent containing two different chemical functional groups, to the end and inorganic materials, such as glass fiber, the silicate, the silanol groups on the surface of the metal oxides reacts covalent bond; At the other end and polymer binders or covalent bonding resin, thereby to coupling two incompatible materials.
(2) the surface infiltration theory, think silane coupling agent to improve the surface tension of the glass fiber or other inorganic materials, and even make it is greater than the surface tension of resin matrix, and thus to resin on the surface of the inorganic matter, infiltration and deployed, improve the wetting ability of the resin for inorganic reinforced material, make resin and inorganic reinforced material sticking together well.
(3) deformation layer theory, that silane coupling agent is plastic in the interface, it can be on the interface to form a flexible deformation is greater than 10 nm layer, the deformation layer has the ability to heal the damage, not only to relax the prestressed interface, and can prevent the crack extension, it can improve the interface bonding strength.
(4) constrained layer theory, composite reinforced material high modulus and low modulus resin between the interface zone, and silane coupling agent as one part of it.Silane coupling agent can not only with inorganic adhesive surface, but also can react with resin, polymer can be "binding" on the interface.When this interface OuDeMo between inorganic reinforcing materials and resin, the amount of stress can be evenly.
(5) reversible hydrolysis theory, think the presence of water silane coupling agent and glass fibers produced by stress fracture, but can be reversible to heal.Such on both the theory of constraint layer at the interface between the rigid area by resin and silane coupling agent (crosslinked), but also allows the stress relaxation, the chemical bond theory and constraint theory and deformation layer into harmony theory.This mechanism can not only explain the interface coupling mechanism, but also can explain the effect of stress relaxation and the function of the resistance on the surface of the water conservation.
Inorganic pigments and fillers in the coating liquid organic phase dispersion can be divided into the wetting, depolymerization and stabilization of resistance (flocculation) three stages.Due to these natural hydrophilic inorganic pigments and fillers, easy adsorption on the surface of a layer of water, so the nonpolar hydrophobic makings is difficult to make its wetting and dispersing.With silane coupling agent pretreatment of inorganic pigments and fillers, surface modification, silane can replace pigment or filler on the surface of the water, coated particles, the R group, become oil-wet, hydrophobic, and easy to be basic material wetting.After wetting, binders molecules insert between inorganic pigment or filler particles, to separate them, dispersion stability, prevents the precipitation and agglomerate. Inorganic pigment and filler surface after silane coupling agent treatment, reduced and have been structured effect, make the paint viscosity reduce, eliminate the flocculation and even increase the amount of pigments and fillers to add will not affect the coating liquid, and pigments, good dispersion of filler particles makes the final film covering power, color and tinting strength were improved.

(source:http://www.ac-chem.net/news/theory-of-silane-coupling-agent-95db.html)

Using method of silane coupling agent

Application method of silane coupling agent has two kinds: one is to mix the silane with aqueous solution, and use it again after treatment of inorganic powder mixed with organic polymer or resin binders, namely pretreatment method; Another method is to silane and inorganic powder (such as packing or pigment) and organic polymer binders, namely migration method. The former method of surface modification treatment effect is good, is a common method of surface modification.
Most of the silane coupling agent to match into aqueous solution before use, even if its hydrolysis in advance. Hydrolysis time according to the varieties of the silane coupling agent and pH value of solution vary, ranging from a few minutes to tens of minutes. General control configuration of the aqueous solution pH value between 3 ~ 5, pH value is higher than 5 or less than 3 will promote the formation of polymer. Therefore, has been configured, hydrolysis of silane coupling agent can't placed too long, otherwise it will polycondensation and failure on its own.
The dosage of the silane coupling agent is related with coupling agent varieties and the area of the packing, silane coupling agent the parcel cover according to the different varieties of the silane coupling agent vary. When it is not know the specific surface area of inorganic powder data or the minimum coated area of the silane coupling agent, dosage of silane coupling agent can be selected for the quality of inorganic powder 0.10% ~ 1.5%.
Most of the silane coupling agent can be used for surface modification of dry, can also be used for wet surface modification.

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Molecular structure and mechanism of action of silane coupling agent

Silane coupling agent is a kind of low molecular organosilicon compound with special structure, and its general formula is RSiX3, type R has affinity with polymer molecules or ability to respond to the activity of functional groups, such as oxygen radicals, sulphur, vinyl, epoxy group, propyl amide, ammonia, etc; X represents the alkoxy to hydrolysis, such as halogen, alkoxy, acyl oxygen radicals, etc.
In the coupling, the first X base water forming silanol, then react with inorganic powder particles on the surface of the hydroxyl, formation of hydrogen bonds and condensed into - SiO - M covalent bond (M says inorganic powder particle surface). At the same time, silane molecules silanol and mutual association in forming the reticular structure of the membrane covering the surface of powder particle, the organic inorganic powder surface.

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The basic introduction of silane coupling agent

Silane coupling agent, also known as silane treatment agent, primer, is a kind of low molecular organosilicon compound with special structure, and its general formula is RSiX3, type R has affinity with polymer molecules or ability to respond to the activity of functional groups, such as oxygen radicals, sulphur, vinyl, epoxy group, propyl amide, ammonia, etc; X represents the alkoxy witch can hydrolysis, such as halogen, alkoxy, acyl oxygen radicals, etc.
The silane coupling agent is a kind of organic silicon monomer with two or more different reactions in the molecule, which can be chemically bonded with organic and inorganic materials(coupling), increase the adhesion of two kinds of material. In the general formula n is 0 ~ 3 integers; X represents a hydrolyzable  functional group, it can be with methoxy, ethoxy, cellosolve and inorganic materials (glass, metal, SiO2) coupling reaction; Y for organic functional groups, such as vinyl, ethoxy, amino, epoxy group, methyl acryloyl oxygen, thiol groups, etc. with inorganic materials, all kinds of synthetic resin, rubber coupling reaction. The typical performance of silane coupling agent in the following table: used in glass fiber, inorganic filler surface treatment.Used for sealants, adhesives and coatings thickener. Also used in the immobilized enzyme attached to the surface of glass substrate, oil well drilling sand, make the brick with a hydrophobic surface, make the surface of the fluorescent coating has high resistance, improve the liquid chromatography in organic glass surface absorption capability, etc. By silicon chloroform and olefin with reactive groupreactive group bonus then through alcoholysis under catalytic system under the platinum catalyst.

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The Viscosifying Ability Of Silane Coupling Agent

Silane coupling agent can improve the bonding strength, water resistance,  weather resistance, etc. Silane coupling agent can solve the problem of long time can not be bonded. Silane coupling agent as tackifier effect principle is that it itself has two groups: A group can be sticky and skeleton materials; While another group can be combined with polymer materials or bonding agent, thus in higher bonding interface formed strong chemical bonds, greatly improve the bonding strength.Silane coupling agent application in general there are three ways: one is as skeleton material surface treatment agent; two is added to the binder, three is directly added to the polymer materials. From the full play to its efficiency and reduce the cost of the point of view, the first two methods are better.

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The research trend of silane coupling agent

The current commonly used three alkoxy silane coupling agent as the type, but three alkoxy type coupling agent could reduce the stability of the polymer matrix, so in recent years two alkoxy type attention to research and application of coupling agent.
Synthetic polymer with active silicon alkyl is also one of the developing direction of silane coupling agent, in this kind of coupling agent on the adhesive resin has better compatibility, can be formed in the glued surfaces a side, thus has better adhesive effect.
Base silane peroxide is also in recent years to research a kind of coupling agent, its characteristic is under the action of heat, decomposition of coupling agent generates free radicals, can happen with olefin polymers crosslinking, so as to promote the adhesion of vinyl polymers.
One of the important applications of silane coupling agents is the production of water crosslinked polyethylene, this process was developed by the United States dow corning corporation, has been commercialized.In recent years, the domestic in deal with wool fabric with silicone emulsion experiment, found with silane coupling agent and silicone emulsion and used, can improve the performance of wool fabric.

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Siloxane

Siloxane , molecular formula: (R2SiO) x, nature: containing Si - O - Si key constitute main chain structure of the polymer.Traditionally called organic silicon or silicon ether, may be linear, circular or crosslinked polymer.
The basic information
Name: siloxane;Water soluble: 60;Transport of dangerous goods number: no;Appearance: colorless transparent liquid;Nickname: polydimethylsiloxane;Dangerous symbol: no;The molecular weight (R2SiO) x;CAS login number: 63148-62-9;Flash: unknown;Boiling point: no N/A;Safety description: flammable items;Chemical formula: PDMS;Risk description: low temperature storage;Melting point: no N/A;Application: daily consumer goods;Density: 500000. 500000. 1 million

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The selection of crosslinking agent

For different adhesive, should choose suitable its crosslinking agent used, it have the following requirements for the crosslinking agent:
1. The reactive groups of crosslinking agent can react with components in adhesive to form crosslinking structure.
2. The crosslinking efficiency is high, just add a small amount of effort to get a stable crosslinking structure.
3. The crosslinking speed is appropriate, too fast or too slow is adverse.
4. The mixed use of several kinds of crosslinking agent, can obtain the best comprehensive effect.
5. Stable crosslinking agent in the processing and storage period, do not produce harmful reaction and cohesion function.Non-toxic, without excitant, do not pollute the environment.

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Use silane the note

1. The system temperature is below - 170 ℉ (112 ℃), otherwise it may sucked in air to form explosive mixture.

2. Don't let the silane contact with heavy metal halide and halogen, silane and their violent reaction. Purging system carefully to prevent residual degreasing agent, containing halogen or other chlorinated hydrocarbons.

3. Use two to three times the working pressure on the system to conduct a comprehensive pressurized leak detection, it is best to use helium. In addition, it shall establish and implement the conventional leak detection system.

4. The system leakage, or for other reasons opened, you should use vacuum or inert gas purging method air purge system water clean. Before open any equipped with silane system must use inert gas purge system in an all-round way. If any part of the system there is a corner or may remain silane, purging of the system must be vacuum circulation.

5. Silane emissions should be where they are to a special processing, it is best to burn it. Even if low silane concentration is also very dangerous, not exposed to the air. Silane was inert gas dilution can also after emptying into non combustible gas.

6. Should according to the requirements of the American association of compressed gas storage and use of compressed gas. Local may have special requirements for storage and use of gas equipment.

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Types of epoxy resin hardener is introduced

epoxy resin hardener type introduces multivariate amine hardener - fat epoxy resin cured with excellent mechanical properties, electrical properties, chemical resistance, and thus widely used. hardener is one of the epoxy resin curing the necessary raw materials, otherwise will not curing epoxy resin. As to meet the needs of various applications, you should use the corresponding hardener. There are many kinds of hardener, are presented below:

Ethylenediamine EDA H2NCH2CH2NH2 60 active hydrogen equivalent molecular weight 15 colourless liquid Resin with 6-8 per 100 standard of performance: toxic and irritant smell, volatile, low viscosity, fast curing at room temperature. Used for bonding, pouring and coating. The amine with the increase of molecular weight, viscosity increases, the volatile and toxic decreases, and performance improvement. But they put a big heat, it is suitable for the shorter period. In general the smaller the higher the molecular weight they affected by the match the amount. Long-term exposure to multiple amine fat can cause dermatitis, their steam highly toxic, must be very careful when operating.

Divinyl three amine DETA H2NC2H4NHC2H4NH2 molecular weight active hydrogen equivalent colourless liquid 20.6 per 100 103 standard resin with 8 to 11. Curing: 20 ℃ + 100 ℃ for 30 minutes or 2 hours 20 ℃ for 4 days. Performance: the applicable period of 50 grams of 25 ℃ for 45 minutes, thermal deformation temperature of 95-124 ℃, the bending strength of 1000-1160 kg/cm2, the compressive strength of 1120 kg/cm2, the tensile strength of 780 kg/cm2, elongation is 5.5%, the impact strength 0.4 ft - pounds/rockwell hardness of 99-108. Dielectric constant (50 hz, 23 ℃), power factor 4.1 (50 hz, 23 ℃) 0.009 volume resistance 2 x1016 Ω - cm at room temperature curing, toxicity, heat quantity, suitable period is short.

Triethylene tetramine TETA H2NC2H4NHC2H4NHC2H4NH2 molecular weight 146 active hydrogen equivalent 24.3 colorless viscous liquid Every 100 standard resin with 10 to 13 of curing: 20 ℃ + 100 ℃ for 30 minutes or 2 hours 20 ℃ for 7 days. Performance: the applicable period of 50 grams of 25 ℃ for 45 minutes, thermal deformation temperature of 98-124 ℃, the bending strength of 950-1200 kg/cm2, the compressive strength of 1100 kg/cm2, the tensile strength of 780 kg/cm2, elongation is 4.4%, the impact strength 0.4 ft - pounds/rockwell hardness of 99-106. Room temperature curing, toxicity was slightly lower than divinyl three amine, put a big heat, it is suitable for short.

Four ethylene five amine TEPA H2NC2H4 (NHC2H4) 3 nh2 molecular weight 189 active hydrogen equivalent 27 brown liquid Resin with 11-15 per 100 standard performance.

More ethylene polyamine PEPA H2NC2H4 NHC2H4 nNH2 light yellow liquid Resin with 14 to 15 per 100 standard of performance: the lower toxicity, low volatile, applicable period is longer, and cheap.

Two propylene three amine DPTA H2N (CH2) 3 NH (CH2) 3 nh2 molecular weight 131 active hydrogen equivalent 26 light yellow liquid Resin with 12 to 15 per 100 standard performance with TETA.

Dimethylamino propylamine DMAPA (CH3) 2 n (CH2) 3 nh2 low viscosity liquid Resin with 4 to 7 per 100 standard bigger toxicity, curing and two catalytic reaction, good adhesion, flexibility, long shelf life.

Diethylamine base propylamine DEAPA (C2H5) 2 n (CH2) 3 nh2 molecular weight 130 active hydrogen equivalent 65 low viscosity liquid Every 100 standard resin with 4 to 8 of curing: 60-70 ℃ for 4 hours. Performance: the applicable period of 50 grams of 25 ℃ for 4 hours, heat distortion temperature 78-94 ℃, 920-1050 kg/cm2, compressive strength tensile strength of 480-640 kg/cm2, the impact strength of 0.2 feet - pounds per inch Rockwell hardness of 90-90. Dielectric constant (50 hz, 23 ℃), power factor 3.75 (50 hz, 23 ℃) 0.007 medium temperature cure, low temperature performance is good.

Trimethyl six methylene diamine TMD (H2N) 2 (C6H9) (CH3) 3 colourless liquid cold curing, long period and low toxicity. Every 100 standard resin with 21 curing: + 80 ℃ 80 ℃ for 1 hour, 2 hours. Performance: the applicable period 400 grams of 50 minutes 25 ℃ and 50 ℃ for 10 minutes, Martin heat resistant 92 ℃, bending strength, 1150 kg/cm2, the impact strength of 20 kg - 0.0009 cm/cm2 tg delta (23 ℃, and 100 c/S) surface resistance 5.4 x1011 Ω (300 v) volume resistance 9 x1015 Ω. Cm (300 v) in the curing temperature, low temperature performance is good.

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Specific mehtod use of silane coupling agent

How to use silane coupling agent Specificly, here are two specific method of use

(1) Pre-packing method

The solid filler into the blender (high-speed solid mixer HENSHEL (Henschel) or V-type solid mixer, etc.), and the silane solution is sprayed directly on the packing and mixing, the higher the speed, the better dispersion. General stirring for 10-30 minutes (slower, longer), filler treatment after drying should be at 120 degrees Celsius (2 hours).

(2) an aqueous solution of a silane coupling agent

(Glass fiber surface treating agent): glass fiber surface treatment agent normally comprises: a film forming agent, an antistatic agent, a surfactant, a coupling agent, water. The coupling agent is generally used in an amount of 0.3% -2% of the total treatment agent glass surfaces, the first aqueous solution 5 times with an organic acid or salt PH value is adjusted to a certain value, under sufficient stirring, a silane was added until clear, then adding the remaining ingredients, for poorly soluble silane, isopropyl alcohol available solubilization. In the drawing process in the glass surface treatment agent is sprayed on the glass and dried to remove the solvent and water.

(3) underside Act

5% -20% of the silane coupling agent was the same described above, by coating, brushing, spraying, dipping treatment substrate surface, to dry out at room temperature for 24 hours, preferably baked at 120 ℃ in 15 minutes.

(4) Direct Addition

Silane may be added directly to the filler / resin mixture, the resin and filler are mixed, the silane in the blend can be directly sprayed. Coupling agent is generally used in an amount of 0.1% -2% filler loading, (according to the diameter of the filler decision). Was then added over a silane resin / filler molding (extrusion, compression molding, coating and the like).