The construction mode of water-based wood coating is shallow

0 Foreword
We often say that paint is a semi-finished product, only when it is coated to different substrate surfaces, the formation of a complete coating film can achieve its use value. The coating is transformed from a liquid fluid (except for powder coatings) into a solidified coating film, attached to the substrate surface to decorate and protect the object being coated. We usually take the excellent performance of solid-state coating film as our goal, excellent formulation development and good production process is our guarantee of high-quality coatings, coating construction in the process to play a vital role . As the saying goes, "three-point paint, seven-point construction", although not so much proportion, but also stressed the importance of construction.
Inside and outside the wall latex paint coating film on the flatness, delicateness requirements are not high, texture coating even requires rough texture, and some coatings such as 3C plastic paint, the surface effect requirements are very high, can not accept a little imperfection. There are a variety of effects of wood coating, such as mirror smooth wood floor paint, but also requires a rough texture of outdoor wood coating, there are bright as the new modern furniture paint, but also return to the true American coating effect paint, there is a display of beautiful wood original style of open coating, but also completely no wood closed solid color coating. In addition to the performance of the coating itself, the construction process also plays an extremely important role in realizing the total coating effect of this forest.
with the gradual transition of wood coating to hydration, the construction process of water-based wood coating also appears new changes. Some water-based wood coatings can take a simpler construction method, some in order to achieve the effect of solvent-based coating construction process becomes more complex, some water-based wood coatings can take a more efficient construction method, and some have to adjust the formula to meet the new construction requirements. For different wood materials, different coating requirements, different construction environment, different work parts shape and size, water-based wood coating users apply different construction methods and processes, for consumers to present a perfect water-based wood coating coating. The following is a brief introduction to the various construction methods of water-based wood coatings.
1 Water-based wood coating construction method
1.1 The most traditional construction method - brushing
lifting wood coating, we can think of the most traditional construction method is brushing. From the exquisite lacquerware in the ancient tomb of Changsha Ma Wang heap, to the on-site painting of anti-corrosion wood relatives in modern residential areas, as well as the painting of some family door sets, window sleeves and furniture, you can see the figure of the worker master. Solvent-based coating film resin is dissolved in organic solvents, resin is fully stretched form, so the brushed solvent-based coating film gloss and leveling are higher. Water-based wood coating resins are mostly emulsion-like dispersion in water, resins are sperical and particle sizes vary, so the luster and leveling of water-based wood coatings are worse than solvent-based coatings. Compared with water-based wood coatings, solvent-based coatings, especially nitro coatings are more suitable for brushing, we used to see a variety of hand-sweeping paint in building materials supermarkets belong to this type.
water-based wood coatings are still used in some places, especially outdoor corrosion-resistant wood works that require on-site construction, as well as some refurbished wooden buildings. In many countries in Europe and the United States, especially many families in Canada are keen to live in wooden houses, the vast majority of these cabins in China's Jiangsu and Zhejiang region production, factory has done wood coating, generally using water-based pure acrylic wood coating, than solvent-based coatings have better weather resistance.
painting is pure human labor, without the help of any modern equipment, so the performance of water-based wood coating requirements are very high, the construction master craft requirements are also very high. Brush coating requires the paint to have a faster drying speed, and requires the construction paint in the facade paint performance is good and can not flow. Brushing water-based wood coating requires a good leveling of the coating film, otherwise the surface of the coating will leave obvious brush marks. For the surface requirements of the coating film, each brush paint, drying also need to be sandpaper polishing. If the paint leveling is not good coating film will be mostly polished off, so it needs to be coated many times, "do more than half the work" is to describe this state. The greatest benefit of water-based wood coating brushing is that neither the site construction master nor the owner who stayed afterwards has to endure the pungent taste of solvents, which can be operated according to non-hazardous materials during the production, transportation and sale phases of the coating.
1.2 The most conventional construction method - spraying
the so-called spray is that the paint with a certain pressure from a small hole, because the paint left the nozzle, the pressure disappeared instantly, so that the liquid coating atomized into a number of fog points to the substrate surface. Depending on whether the use of air source as power, but also can be divided into airless spray and air spray, the former is often used for the construction of latex paint inside and outside the wall, and the most typical application of the latter is the construction of wood coating. Air spray can achieve a better atomization of the coating, can make the coating sprayed to the substrate surface, to a certain extent to prevent hanging.
additional spray construction can be applied to any surface shape. By adjusting the size of the air pressure, the volume of paint flow, the speed at which the spray gun moves, the distance of the spray gun from the substrate, and the angle of the spray fan surface, you can control the thickness of the coating, the efficiency of the coating and the flatness of the coating film. Solvent-based wood coatings and water-based wood coatings are also suitable for spraying construction, but solvent-based coatings are more volatile after atomization, smell heavier, less safe, and water-based wood coatings do not have such a problem. In addition, spray paint generally requires viscosity than brush coating viscosity is low, often 20 to 25s (4 cups).
Generally speaking, spraying to take the manual operation of the way, by the painter hand-held spray gun coating, which is very high technical requirements for the worker master, paint both requires a better plumpness and can not hang, need to be careful, focused and physically good. Most of the time the worker master is standing operation, for solvent-based paint, the worker master also have to endure solvent volatility, so the coating work is often a higher wage in the furniture factory. Most woodworking and furniture factories have dedicated coating workshops, in addition to air compressors and spray guns, large and small coating platforms and hangers, the walls of the workshop are equipped with exhaust fans to remove volatile solvents and paint fog points that do not fall on the substrate surface. Now many wood products factory coating workshop using spray water curtain cabinet, the paint has not fallen on the substrate with water curtain to recover and no longer discharge into the air.
In order to improve the efficiency of construction, many furniture factories set up spray assembly lines, the use of re-type spray guns, set the flow, pressure, spray angle and distance of the spray gun, as well as the speed and station of the assembly line, through the cooperation of several spray guns, to achieve efficient automation of the coating. For wood furniture with complex shapes, industrial robotic arms can even be used for perfect coating, keeping the nozzle to substrate surface consistent for perfect coating. In order to improve the drying speed of coatings, there are special drying equipment in the modern coating workshop, so that spraying - drying - polishing - re-spraying can form an efficient working process. The drying of solvent-based coatings is often forced by hot air, which is accompanied by a large amount of solvent volatility in a short period of time. Dry water-based wood coating the most advanced equipment is infrared drying equipment, the use of specific wavelengths of infrared light to trigger the resonance of water molecules and leave the coating surface, so as to achieve the lowest energy consumption conditions of film drying.
1.3 The most labor-pampering construction method - wipe
the so-called wipe is to use cotton or non-woven cloth full of paint to wipe back and forth on the surface of the wood. Wipes are not used alone and are often used to color wood. In the primer or paint mixed with color essence direct spray can also be colored, but this construction process often gives the impression that the color is inside the paint, floating on the wood surface, rather than the wood originally has a natural color, lack of layering. Therefore, a separate coloring process is necessary to change the color of the wood before painting. Alcohol-soluble color essence or rub color treasure, is often red, yellow and black 3 color essence in accordance with the formula to adjust to the required color, filled with wood coating after stirring evenly. Solvent-based paint is not absorbed by wood, so you can directly wipe on the wood white blank, light color of the place rub cloth can stay more time, the color of the dark place can be wiped several times until and around the color is thick and consistent.
-based wood coatings cannot follow such a construction process. Wood belongs to the absorbent substrate, different parts of the absorption speed is different, wipe cloth to maintain the amount of color essence, wipe cloth movement speed will lead to uneven color and not easy to correct. The usual process is to make a transparent thin primer on the white blank surface and then polish the wood surface after drying. On the one hand, to prevent water-specific coloring caused by the wood's "expansion", on the other hand can ensure that even if some parts of the color is too deep can also be wiped through several times the color. Often a single wipe color is light, the current popular process is that no longer use the resin-free system of color polishing, but in the color essence to add alkali-soluble resin or directly add water-based wood coating (need to see the stability of the system), improve the wet adhesion performance of color essence.
if necessary can also be in the follow-up water-like wood primer, paint mixed with a small amount of color refinement to deepen coloring and finish, so-called bottom coloring, face repair is so. Coloring requires the worker master to concentrate on the woodwork, any color unevenness, color difference, floating color is not acceptable. Every inch of wood is wiped back and forth many times until the color is completely uniform, which is a laboring job. In addition, the surface of the pencil is coated with water-based wood coating, is also the use of wipe method, but it is not the same as we traditionally understand the wipe.
pencils pass from top to bottom from a rubber bowl filled with paint, and the rubber at the bottom rubs the water-based wood paint from the rubber bowl on the white blank surface of the pencil as it rubs against the pencil. Pencils, whether round or hexaring, can be wiped in this way. The author has seen such a construction scene in a pencil factory in Yiwu.
1.4 The simplest way to do this - immersion
coating is a semi-finished product, and we want to work in the fastest way to turn the semi-finished product into the final coating. There are many ways to achieve this transformation, and immersion is undoubtedly the most convenient one. We have been lamenting that the coating performance of water-based wood coatings can not catch up with solvent-based coatings, construction performance and solvent-based coatings there is a gap. However, in the construction mode, water-based coatings have a great advantage, especially immersion construction. Because water as a thinner its cost is almost zero, and the paint tank open after the solvent evaporation into the atmosphere is not harmful to the environment, no harm to the construction staff, so immersion construction has become a patent for water-based coatings, which is the most widely used water-based wood coatings.
But there are some limitations to the water-based wood coating used in the coating, for example, because the verticality of the surfaces of the woodwork is not the same, resulting in the same viscosity of the water-based wood coating paint performance is not consistent. The horizontal surface coating film is thicker, while the vertical surface coating film is thin and thin. The phenomenon of hanging is a headache, just out of the paint tank woodwork surface has a uniform coating film, due to gravity reasons did not wait for the coating film drying will form a flow hanging, greatly affecting the aesthetics of the coating, which is determined by the characteristics of the coating construction method.
In order to overcome this shortcoming, the workshop using the immersion process has an inverted centrifuge, throwing out too much paint on the work piece, while taking a forced drying method, before the coating film again forms a flow hanging let the coating film dry. We can also properly change this disadvantage by using some fluid-modified additives, commonly referred to as thickeners. Anti-flow hanging and leveling is a pair of contradictory paint characteristics, anti-flow hanging good paint leveling is bound to be poor, we optimize the formula is to achieve anti-flow hanging and leveling balance. Open coating does not need a plump coating film, color paint to add 3 to 5 times the water mixing well, paint with color penetration into the wood guide hole to show the natural texture.
For the characteristics of immersion construction, the woodworking works that choose this construction method are often in complex shapes and not suitable for other construction methods, or some woodworking works that require various parts to be assembled and then coated later. Woodworking work pieces that do not require film plumpness are also suitable for immersion. At present, the most widely used woodworking works tend to be outdoor furniture and outdoor wood products. In Zhejiang Province, especially in Anji area, there are many outdoor furniture factories, the production of a variety of outdoor leisure chairs, tables, wooden flower beds, wooden fences.
In the coating workshop to prepare a large paint slot and with drying function of the hook assembly line, workers put these outdoor wood products in the paint tank stirring a few times, on the one hand, let the paint fully soaked in the furniture, on the other hand, the paint tank can be mixed with a variety of colors of the paste, because iron red iron yellow and carbon black (or iron black) sinking speed is not the same, do not often stir will be color layering.
1.5 The most peculiar way of construction - rolling paint
the author has been to a small village in the Linhai Mountains of Zhejiang Province, where every household makes wooden handles, its output accounted for almost half of the country. Most of these wooden handles are used for children's skipping rope handles, rocker handles for factory crimpens, wooden cigarette butts for export to Arab countries, and so on. Customers have always stressed the need for water-based wood coating fast drying, anti-wear, scratch-resistant, fast coloring, good fastness. With full of suspicion, the author decided to personally go to the scene to find out exactly.
Into the customer's dedicated coating workshop to see, on one side is like a concrete mixer rotating roller, spray gun paint in the above-ground paint bucket into the drum, on the other side is a large earth stove, inside the processing woodwork workpiece after the excess corner material and wood chips, the blower non-stop hot wind into the center of the drum. From time to time, the customer reaches into the large roller and randomly picks up a few wooden handles to see the paint. At first, some wooden handles were painted only on the head and white at the tail; some were just speckled in color, and some were barely colored, but over time, all the wooden handles were evenly colored and did not stick to each other.
See here finally understand that the roll coating here is not painted with rollers, but placed in the rollers, using a concrete mixer-like rollers constantly turn, through the wood workpiece friction between each other, the sprayed paint to each other. According to customers, in the southern region of Zhejiang, especially Lishui City Yun and County, this construction method is very popular.
County is the world's wooden toy processing center, including a variety of wooden building blocks, puzzles and crafts. The factories there are basically roller-coated. This coating method requires water-based wood coating fast-drying, anti-wear, anti-adhesive, high gloss, high solid content, low viscosity, are currently using Zhejiang local water-based or semi-water-based coatings. This kind of water-based wood coating can meet such basic requirements, but in addition to water resistance is not good enough, and the water-milk type of paint is often not suitable for this coating method.
1.6 most efficient construction method - roller coating
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