Orange powder coating formulation design

'Sophie Designof PowderSWithOrangeTexture
Chen Fusheng Li Baocai (Anhui ShenJian Chemical Co., Ltd.)summary: Based on the patterning mechanism of orange powder coating, this paper discusses the effectof of floating agent, face filler dosage, baking conditions on orange pattern, and puts forward a way to solve the coating film dew and thick coating flattening1 foreword
with the increasing use of powder coatings and application range, orange powder coating with its special texture effect to cover up the defects of the substrate itself, and can avoid the production of particles, shrink holes, leveling and other coating ills, its excellent decorative properties by people's favororange powder is also known as wrinkle powder, its production method generally has to increase the filling method, the use of different curing agent method, add floating agent method, add orange grain agent methodAt present, the market because of the first two methods of the production of orange grain powder by the mechanical performance is not good or texture size adjustability of the ills, rarely used by powder manufacturers, mainly the application of the addition of floating agent, orange grain agent and other methods to make orange powderThis paper gives a brief description of the patterning mechanism and formula design of these two methods2 into the pattern mechanism
the powdering process of adding floating agent method is divided into two stepsFirst of all, the base powder of the main material is prepared, and then a certain amount of floating agent is added by dry mixing methodThe patterning mechanism is that the base powder in the melting flow, because the formula does not contain leveling agent or leveling agent do very little, the surface tension of the molten powder is higherFloating agent is generally with the resin compatibility of limited substances, surface tension is small, not mixed with the main material to squeeze, so the entire molten powder coating surface formation surface tension gradient, according to the Bernal vortex flow theory, in the surface tension is small place to form a shrinkhole, so that the coating film formed a uneven orange surfacethe patterning mechanism of adding orange grain agent is consistent with the patterning mechanism of adding floating agent, the difference between the orange grain agent and the main material mixed melt extrusionOrange agent is also a substance with limited compatibility with resin, melting point is higher than the resin, in the melting extruded will not melt, but evenly dispersed in the main material3 experimental study
the formula used in this experiment is shown in table 1 the test formula for table 1 orange-print powder coating
1
2
3
4
5
5
6 polyester resin
35
35
30
30
30, a company SJ-3b
65
65
a company SJ-4-C flatlast 0.1
0.1PV
88 epoxy resin
35
30
30
30
A company SJ-E12
TGIC
5
5
a company SJ-TGIC titanium dioxide
20
20
20
2
0
20
20
20
sulply sulphate 10 10
20
10
10
0.
3
0.
3
0.3
0.3
0.3
0.3
carbon black 0.1
0.1
0.10.10.10
0.
10
0.00 1
orange grain agent 0.1
0.1
floating agent
0.7% 1% 1% 1% : curing conditions of 180 degrees C / 20min
4 discussion
through the test found that the following factors have an impact on the performance of orange powder 4.1 the effect of floating agent dosage on the size of orange grain
as shown in Table 1, formula 1 and formula 2 of the amount of floating agent is different, formula 1 coating orange grain than formula 2 orange grain is larger, but there is no formula 2 coating film pattern uniform This is because the formulation 1 floating agent dosage is small, in the powder melting film surface tension gradient is not uniform, so that the surface of the coating surface of the shrinkhole (concave surface) uneven distribution, resulting in a larger and uneven orange pattern, formula 2 is just the opposite 4.2 face filler dosage on the size of orange formula 2 and formula 3 of the amount of face filler is different, from the resulting coating of orange grain, formula 3 than formula 2's three-dimensional sense is stronger, because formula 3 of the face filler plus large, in melting time The surface tension and melting viscosity of the main material are much higher than the formulation with low amount of pressure filler, so a larger surface tension gradient is formed with the floating agent with small surface tension, while the high melting viscosity leads to low coating mobility, thus forming a stronger three-dimensional sense of orange surface 4.3 thin coating bottom and thick coating flattening problem
as mentioned above, the coating film formation of orange pattern is mainly caused by the use of floating agent to produce a continuous shrinkhole, so whether the coating film can form orange pattern, with the addition of floating agent and orange agent to make the coating in melting surface tension gradient and shrink the situation; The fluidity of the coating can be expressed in the following formula: h2
g - - - - - - - - -
the of the paint fluidity h - wet coating film thickness - viscosity v - cross-section of the surface tension gradient from the upper-level can be known, the fluidity of the coating and coating thickness has a greater relationship According to the Bernal vortex nest theory, the coating moves from the bottom to the top under the action of surface tension, and the coating moves from the upper layer to the bottom under the action of gravity The surface tension at the coating shrink hole is often small, and the liquidity is large, if the coating is too thin, then the downward flow of the paint is far from sufficient to supplement the amount of paint flowing upward, it will produce the phenomenon of exposed bottom shrink hole; Therefore, the problem of solving the thin coating bottom is that, on the one hand, do not spray too thin, on the other hand, choose to use the surface tension and the surface tension of the main material is not much different from the floating agent or orange pattern agent varieties; 4.4 the effect of the baking conditions on the size and three-dimensional sense of orange pattern
the orange pattern size and three-dimensional sense of strength discussed above refers to the orange surface obtained by baking and curing at a constant temperature of 180 degrees C In practice, there are many cases where the parts are sprayed and then placed in the oven, rising from room temperature to 180 degrees C, or the oven temperature is higher than 180 degrees C The former relative to 180 degrees C temperature baking to obtain the orange surface to be flat, while the latter obtained the orange pattern three-dimensional sense is generally stronger than 180 degrees C temperature baking to obtain the orange surface This is because in the process of rising from normal temperature to 180 degrees C, the resin component in the main material in about 100 degrees C will begin melting flow, in the temperature range of 100 to 180 degrees C, the main material with the temperature increases, viscosity decreases, the liquidity increases; Compared with C constant temperature and baking conditions, the viscosity of the coating and the increase in fluidity time is longer, which is not conducive to the formation of floating agent (orange grain agent) coating film shrink hole, can only form a smaller orange pattern, or even can not form an orange pattern; However, when the temperature is too high, the curing speed of the main material too fast inhibits the floating agent (orange agent) so that the coating film produces a surface tension gradient to form a shrinkhole, so only can get a flat coating surface Therefore, under the above two non-constant baking curing conditions, the formulation design appropriately extends the glue time of the main material and selects the floating agent (orange grain agent) with a large surface tension 5 conclusion
orange pattern powder coating orange pattern size and three-dimensional sense of strength is not only related to the amount of floating agent, face filler dosage, baking temperature, but also with the active composition content of floating agent, resin viscosity, color filler oil absorption and other factors In order to make orange-print powder coating, we must carefully consider the above factors on the formation of orange pattern, in order to obtain a satisfactory orange surface references: 1 Qian Fenglin, Yin Yu book editor, paint aids - variety and performance manual, Beijing, chemical industry press, 1990