Why white paint Will turn yellow?

If a friend asks you, that the white color of the Car Why yellow? to boast, then what to say today to share with you.

often said that the yellow paint What Is the concept?

Automotive paint yellow, Is actually a more complex physical and chemical processes, it produces a large extent caused by the characterIstics of the material itself.

that we often say that the yellow paint What Is the concept? The first talk traditional Automotive paint coating process Is divided into four layers, which from inside to outside are electrophoresIs, in the coating, paint, varnIsh.

Is mainly yellow paint varnIsh layer and pigmented layer

we can directly observe the naked eye Is the varnIsh and paint, paint layer that provides us with the most direct sense of color, decide which Car colors, white, black, red.

on the outside layer of transparent varnIsh, we can also see the furniture, paint actually generally yellow thIs Is two yellow, paints and varnIshes.

Is not only a white color Will be yellow Car, the Cars are all aging, Fading, change color, but white color the Car Is a little more obvious.

ChemIstry reason yellow paint what?

first place bragging, then the yellow paint, its chemical reasons for that? It Is the main structural layer of varnIsh are generally polymers.

ThIs common material Is an acrylic resin varnIsh andAmino resins, in addition to some of the additives, such as what diluents, curing agents and the like.

amino resin varnIsh oxidizable yellow

amino resin varnIsh of yellow oxidized relatively easily, it Is relatively low price of raw materials, probably about one ton 13,000 dollars, Common use relatively low-end models would be more a little more.

amino resin varnIsh on the other side, exposed to the air can easily be lost oxidized aromatic primary inside and secondary amines, are particularly sensitive to the oxidizing agent, Is one of the causes yellowing.

thIs Is a bit like our white of the bowl, old yellow lost, Why does not bowl 30,000 dollars one pair of it.

acrylic resin varnIsh easily denatured acrylic resin varnIsh, it Is easily denatured lead yellow, characters do not change Luanxiang, acrylic resin raw material relatively higher price, the price of 15,000 dollars per ton.

in high-end models Will use a bit more, you do not underestimate thIs 2000 dollars, to sell a few dozen people a year a few million million vehicles, 2000 and then take up a sum of money.

may also change color exposure acrylic resin

acrylic resin there Is also a benzene ring, the benzene ring conjugated double bonds becomes quinoid structure in the case of illumination, the image Is the point that Will produce the yellow group.

and a cup inside the bubble Sterculia almost feeling, not just air, sun dryingColor also become, in fact, thIs yellow paint, which Is point-like, floc.

However, because of its relatively high density, with a far away look feel like a whole are yellow, yellow Is not the type of like the wind that turn yellow, and the yellow sun Is not the same.

Acid Rain and varnIshes reaction results in yellow

acrylate thIs resin varnIsh, it Will also lead to yellowing react with sulfuric acid, nitric acid, which has a relationship with our stuff.

In addition to acid rain inside the city Carbonate containing also a small amount of sulfuric acid, nitric acid, nitrous acid.

ThIs Is an acidic substance up, Will produce esterification, generation acrylates, acrylates such Is yellow.

The curing agent can also cause yellowing of the paint

that the curing agent can also cause yellowing of the paint, varnIsh to which it Is reinforcing agent, which during the spraying process in order to accelerate the solidification rate of the varnIsh, strengthening its hardness.

Is relatively well-known Bayer, it produces a curing agent L75 inherently prone to yellowing occurs.

but because of the construction process requirements above, there Is no way use only, Is not the case paint might not do thIs.

Will not oxidative yellowing varnIsh layer

in addition to the fact we just said, conventional four-level hierarchy, there Is a three-layer structure, which Is called 2K paint,Colored, it does not need a varnIsh.

In fact, even that did not only paint varnIsh, or Will be yellow, and that thIs did not varnIsh protects Well, thIs paint direct contact with air more easily oxidized.

physical causes yellow paint what?

microscopic lesions

within the paint relatively close to just the high school chemIstry, as well as physical, thIs in fact, there Is a microscopic paint thIs damage, under certain circumstances it Will be exposed color primer.

that the body manufacturing process, thIs steel Is processed in the shape requirements, a steel plate that come depot level block , to become the cover to become a door, there must have arc shape, it Is to be done out.

During the production of thIs, an internal stress generated, which cause thIs arc shaped slowly begins to deform, then for a long time, and slowly began to be released a little, like to split the same.

internal stress affect the color

make Let’s put thIs Is that you fold the paper, fold it over would not have been just the right always seemed to be slowly separated, although the change uneven but still separate a little bit.

ThIs internal stress, relatively speaking, it Will have impact color, body paint spray painted after the completion of the steel sheet internal stress Is still diffuse, there are standards.

“BT24179-2009年的金属材料残余应力测定”, a measurement result of these stresses yearProbably change 10% to 20%.

can be seen yellowing add up cracks

the above then the metal Will also be spread to the paint, to split, and undermine the integrity of the paint, but thIs Is not to split the split like a melon seeds as meat.

We basically naked eye can not see thIs little crack, but then add up these cracks, it Will make black primer, Will slowly revealed a small crack, it may be vIsible to the naked eye.

ThIs look away dense and crack point, you can see more intuitive yellow, and yellow and the contact with air Huang, exposure to acid rain and the kind of the yellow, slightly different color.

external contaminants cause dIscoloration

Another Is external also cause contamination of color change, the Car Is in open, it Will move, which surface Will form a vortex gas flow.

apart from stationary up to the process, the air suspension Will be deposited in the above paint, or scratches, or on the attachment in it, it Will make the Car changed color.

Such air suspension main component Is silica, the metal salt Will affect, you think the Egyptian pyramids, Sphinx human face like good blow blowing, face almost see clearly.

a number of factors can cause yellowing of the paint

Car Is the same, nothing more than the number of years people blowing a little longer, he said a bunch, what causes it? Chemical itself, the wind blow drying under the sun rain, it changed color.

Then the paint are not placed on the plate, you do all kinds of shape steel plate, it must always endeavor returns to its original shape that a little bit.

so toss down, back and forth so TwIst, we generated less vIsible to the naked eye cracks, the primer color color paint layer and mixed together, and a little yellow stuff came out.

, “said the spare Car” Will give you a day for a small Car practical dry goods, please pay attention to the spare Car, said 60 seconds per day easy to understand Car.