When you buy a new car, all the plastic surfaces inside are real clean looking (and smelling). It has a sort of matte finish and a sort of rough texture. Over the years, these plastic surfaces become very shiny and oily looking. There is an obvious difference in the change. I have a '94 Prelude and this is what the interior plastic surfaces are like. I can't stand it because it looks so "used" (even though I know it is used).

My question is, what causes the plastic surfaces to be this way and is there anything we can do to prevent or fix it?

 

You can avoid the "shiny" look by not using any of kind of cleaner/protectants on your interior plastic. I just wipe down my interior with a damp cloth to remove dust, etc.. and have never had a problem with my cars. Interior looks just like it was new. You may have to use a little soap/water mixture if there is a dirty spot you are trying to remove. If you park outside a lot, use a winshield sunshade to protect the dash from the sun vs. using protectant spray.

 

I've heard that it's mostly due to UV in the sunlight. Most of the interior plastic cleaner/protectant nowasdays offers UV protection. I think using a good plastic protectant such as a 3M product with a dash sunscreen should do the job.

 

Most plastic parts are injection molded. The molds are coated with a mold release agent. This mold release will come to the surface of the plastic over time when the plastic is exposed to UV light. The reason it looks oily is that it is....it's the mold release! I haven't heard of anyway to cure this but it will be even be worse if you clean the plastic with silicone based cleaners, like Armor-All.

 

Typically i use water or glass cleaner on all of my interior surfaces. Griots garage has an interior cleaner that is supposed to eliminate this problem, but I have not tried it yet. Their site is http://www.griotsgarage.com Their reputation is awesome and I use a lot of their other products and highly recomend them. Hope this helps.

 

Wow Utah I'm impressed, you know your stuff. Which brings up the question if then the release agent is at the surface couldn't it be cleaned with a prep cleaner, I know when we clean new bumpers to paint we clean them with a mild TSP solution, but I don't know whether that would hurt the surface. Of course the dash pad isn't injection molded is it, I believe it's vinyl covered?

 

on my prelude, which is already in the advanced stages of shiny-ness, I have tried using a sponge with some simple green, thinking that simple green will act effectively as a degreaser. It doesn't work though. Looks like the shinyness is here to stay (?)

 

All I can say is be carefull what you use on your dash!! I had to use a cleaner on mine to get some sticky crap that my bone head dealer got on the dash. I though it was from the airbag stickers, but after examining other new s2's I don't think it was. Anyway... Now instead of sticker residue I've got a couple little shiny spots on the dash. I called up Top of the line auto enhancement. Spoke with the owner (Irene) who was very helpful. She set me up with a cleaner that would not hurt the dash and the 303 protectant that should have eveything back to normal. She said you need a cleaner that is ph balanced.

Later all.
Tha zach man.

 

There is a certain ineviatability to this. The matte finish that the S2000 had such a nice dose of... on both leather and plastic, is something that will go away with use no matter what you do.

The matte appearance comes from having a 'rough' finish on a microscopic level. Kind of like being 1000 grade sand paper. Over time, wear (from cleaning even) will polish this finish away leaving a shiny look. Since the materials are relatively soft, this can happen rather quickly. Thus, I would suggest that you not rub any plastic or leather surface in the car. That will keep the finish as best as possible. Sponge it off with water or the appropriate cleaner.

Naturally, oils... from molds or cleaners, only accentuate the problem as they fill up the voids in the 'rough' surface.

Unfortunatly, the leather on the wheel and the seats can't avoid this as your hands and butt will polish these over time.

In other words, you can't make time stand still.

Dan