1 introduction

Powder coating in solid powder. Powder generally refers to the solid particles less than 1 mm in diameter. The production of powder coatings is the synthetic resin, pigments, fillers, additives and raw materials, such as premixed, melt extrusion, film pressure transmission, crushing screening process, such as the coating is given priority to with electrostatic spraying. Energy conservation and environmental protection for powder coating performance is excellent, is of the fastest growing coatings at home and abroad in recent years, variety. The data show that, in terms of pure solid, powder coating, 2010 dosage will be to paint the top three line. At the same time, the powder coating related raw material, milling equipment has made great progress. Let's main part, the additives of powder coating raw materials are discussed.

2 the classification of powder coating additives

Fertilizer is powder into the auxiliary material of membrane, can't separate film, dosage is less, in the coating additives generally within 5%, the total but can be targeted to change the performance of the coating or coating. Used in powder coating additives for more solid, or through the carrier absorption become solid, is relatively stable in performance and ability of high temperature, etc. So powder additives is different from the same paint additives, and sui generis. With the rapid development of powder coatings, powder fertilizer varieties are also growing. According to the fertilizer production and application of additives we divided into the following three categories.

2.1 the conventional additives

Is the production of conventional planar ordinary powder coating necessary fertilizer varieties, mainly including flow ping agent, whitening agent, benzoin, flatting agent, dry powder flow agent, etc. Some of these additives can change the flow property of coating, some can change the luster of the film, some can change the flow property of powder in construction, some can improve the storage stability of the powder. Commonly used flow ping agent is polyacrylate, useful also tsinghua castor oil, polyvinyl butyral, vinegar ding cellulose for auxiliary flow ping agent. Our agent is used to improve paint filler dispersion of coupling agent, dispersant, etc. A wide variety of powder delustrant, involved type of chemical reaction, such as the commonly used models launched, 208; Don't participate in the reaction of the physical model, such as extinction wax, 823, 823, etc. Fine powder flow agent use morer powder, plus to be in the final product, such as gas phase silica M - 5, alumina C.

2.2 the texture additives:

Grain fertilizer is to cover up the workpiece surface roughness or obtain beautiful developed by the coating effect of the powder additives, it optimizes the before those tedious formula, powder reached a relatively stable art adornment effect. Main varieties of wrinkles, hammer agent, sand grain agent, the agent, the foaming agent, turtle grain agent, point spread, stereoscopic pattern agent, etc. Texture additive dosage is small, in a few parts per thousand, generally after extrusion, and scattered. And these additives have more strict requirements on the performance of the resin, such as the viscosity, reactivity, glass transition temperature, the content of impurities, etc. Ordinary powder, wrinkles if the resin content of catalyst in high, small grain or grain. Do the grain powder, the demand of epoxy resin organochlorine content less than 0.1%.

2.3 functional additives:

Functional additives is to improve and expand the function of coating additives, these additives is the fastest developing speed in several kinds of additives and most varieties of category, such as resistance to yellowing agent, uv absorber, increased electric agent, defoaming agent, light stabilizer, anti adhesion agent, hardening agent, coupling agent, adhesion promoter, antistatic agent, conductive agent, dispersing agent, mould inhibitor, catalyst, heat stabilizers, flame retardants, wear-resisting agent, etc. These additives in the application in powder coating, as long as don't affect the powder properties, can reference from paint or plastic.

3 the application of powder fertilizer

Conventional fertilizer effect is the same, formula is essentially the same. Such as epoxy resin absorption flow ping agent dosage is 4% ~ 5%, silicon dioxide absorbed called throughflow flow ping agent was 0.8% ~ 0.8%. The dosage of the resin, curing agent, make sure the content in the formula, then recommend the matching calculation, excessive 5-10% curing agent. So now we only to key products of texture additives and functional additives.

3.1 the application of sand grain agent

Making sand grain powder has a variety of methods, add packing or gas phase method of white carbon black, out of difficulties, the powder rate is not high. We used sand grain agent for modification of PTTE, similar to the effect of foreign companies, but its price is only half of imported products, this kind of additive dosage in one over one thousand, add to the powder coatings can have physical separation, extinction effect such as sand, luster can be down to 2 degrees. Compared with the previous packing method, high efficiency, less wear and tear on the equipment, resin may be less than, uniform and coatings is exquisite, feel is good, used with organic bentonite can adjust the size of the sand, if add vinegar ding cellulose in the recipe to make filaments grain effect. At present because of the influence of the Japanese earthquake, fluorine products prices, to company developed not containing fluorine sand grain agent 812, add more similar to 825, 207, effect of equivalent trifoliate Tex - 61. Has been applied to the material powder, its resistance to ageing effect is similar to the original 815.

3.2 flower diffusion agent applications:

Similar with watercolors points out different take the grain, spread in the melt lead paint some flowers spread agent, we call this point pattern powder. Production point flower needs two steps, namely first spend some agent and to the spread of the pigment mixing extrusion, crushing, remains in the 100-150 mesh powder, powder called point. Powder used is similar to the conventional powder, but don't add flow additives, one percent according to the proportion of outside with a little powder can be made into some flower. Along with several different point in some powder powder. Such powder have certain polluting, coating should be slightly after cleaning.

3.3 the wrinkle agent applications:

Wrinkles also called orange lines, the lines of our company agent with one-step wrinkles agent 805 varieties and ldpe-g-nvp floating agent K - 30. Its main ingredients are vinegar ding cellulose and polyacrylate, the corresponding import brand is a CAB - 551, 2874. The use of these two kinds of additives formula broadly similar, 805 of them easy to use, the production of powder wrinkles is relatively uniform, but the stereo feeling and anti-interference ability is a bit poor. Wrinkles with embossed agent K - 30 production powder is stereo feeling and strong anti-jamming capability, curing temperature changes texture effects, but need to sift together the two times. Powder manufacturers according to the actual situation of our factory to choose.

The application of 3.4 hammer agent

Production of hammer powder also have two kinds of method. Was prepared with hammer agent 856 dendritic, shallow dish, and the effect of different stereo feeling hammer powder coatings, with polyvinyl alcohol and secondary process more simple, embossed agent was prepared by the hammer sense is strong, clear texture. Because of the formula of resin of high, need to add organic bentonite or dimethyl imidazole prevent sagging. Formula of the need to add about 1% of the float type aluminum powder, and the available domestic Harbin chapter grave, import PC150, 2081800 00 A brand, etc. Also have factory with embossed agent, reduce artifacts appear show the shrinkage cavity.

3.5 the application of continuous agent

The agent is mainly used for the production of continuous grain (also called water lines or fabric) and checkered powder. The powder surface effect is more beautiful, is used by more security door manufacturer. But such powder have certain toxicity, stimulate an eye, workers easy jealous after contact with the powder. In addition the powder on the thickness of the coating film and baking temperature to the more stringent requirements, formula to add a small amount of polyester can regulate grain and improve the flexibility. There are currently used in epoxy resin, polyester resin, polyurethane resin 3 class agent.

3.6 resistance to yellowing agent application

Powder coating in the process of production or use, after high temperature extrusion and baking processes and some organic polymer degeneration occurs at high temperature oxidation, the color yellow. Powder the function of the resistance to yellowing agent is to preent the deelopment of polymer under high temperature yellowing, prevent coating at room temperature using the yellowing time is too long. Resistance to yellowing agent besides has the yellow group, and compatible with powder resin grafted groups, but also increase the consistency and appearance of coating. Generally content of 1%, 220 ℃ can keep the 30 minutes don't change color.

The application of uv absorber 3.7:

Belong to the stable preventive additives, the product can strongly absorb 270 ~ 380 nm uv light waves, prominent feature is the better thermal and light stability, low volatility, and phenolic antioxidant, hindered amine light stabilizers with synergy, but before uv endanger polymer molecules absorb, protect the polymer from uv rays, so as to improve the coating in different degrees of weathering.

3.8 powder increased electric agent applications:

On the rate of powder and powder particle size, water content of the charge of the particles, powder, spray air pressure, voltage and so on. Powder particles charge can by additives to improve, we call the increased electric agent powder. Its main ingredient is charged groups of organic salt, join in powder ingredients, mixing extruder, and can effectively improve the spraying charge on powder particles, thus improve the rate of powder, and can also overcome the electrostatic shielding effect, make the edges or on the inner surface is easy to powder. We calculate the dosage in 2 per thousand, on a powder rate can be increased by 26%. Used at the moment there are two types of varieties: organic ammonium salt of EDI, used for wrinkles of varieties with low resin content such as sand grain; Organic esters N308, used in the specular powder.

3.9 the application of the powder antifoaming agent:

Powder antifoaming problem more and more be taken seriously. When curing powder coatings, the workpiece or coating itself for a long time, the surface to air and coating film forming time is relatively short, so formed bubbles or pinhole. Is fine wax powder antifoaming agent is widely applied, is typical representative BYK961; Domestic application effect is the best brand is 4430; By ethylene glycol carbonate, can be applied to all kinds of powder. Defoaming agent 4430 can eliminate pores formed by the water and powder itself, also can eliminate iron and aluminum pores caused by the plate, improve the liquidity of powder particles and powder coating, flowing property can replace benzoin eliminates the yellowing phenomenon caused by benzoin. But if a spraying powder coating thickness of more than 200 microns, ills cannot eliminate pinhole.

The application of 3.10 powder flow agent

To realizing the thin coating powder, powder particle size must be small. And powder particle size slants thin, powder particles cluster, when spraying easy blocking a gun, after curing scar. Powder flow agent's main function is used to reduce the friction between the powder particles, thus reduce rest Angle, improvement in the process of spraying powder fluidization, extend the storage period of powder. We produce a variety has been Taiwan, Singapore and other places the manufacturer's approval.

3.11 adhering to add hard series of fertilizer application

Coating surface hardness is powder manufacturers attention, also have good coating products, often in the process of the packing and shipping for friction scratches, make the product quality, our company's anti adhesion agent and a hard agent, is a kind of inertia polyamide materials, can perfectly solve the above problems, and have good anti-pollution performance. Also have factory when doing heat transfer powder, add less than 0.5% of the adhesion agent.

4 the development prospects of powder additives

There are some limitations to the powder coating, such as construction must be electrostatic powder spraying, powder can only be used for metal artifacts; Powder coating must be high temperature baking film, not heat resistance of wood or plastic, as well as the large size can't into the oven artifacts cannot be applied. Powder and glossiness flowing property and reach some level of solvent-based coating, such as car paint, no variety of powder coating can be used on real significance. All of these restrict the application and development of powder coatings. Strength large companies abroad are studying these issues, such as in recent years, domestic sales good picker, trilobites, DE letter, Troy company, set up a sales office in domestic major cities. These materials localization research is the focus of our work. In the 21st century is the century of functional coatings, functional coatings development has a close relationship with additives, the additives are also in the direction of the functional and has many characteristics of composite development.