What is PLA+? How is it different from PLA?

Question

Question

What is PLA+? How is it different than PLA? I'm looking for science, composition, formula, safety concerns (or lack thereof), etc.

Background

I picked up a roll of PLA+ at Microcenter (their in-house Inland brand) because it was on clearance. I didn't even notice the "+" until I decided to try that color, and then I noticed it on the sticker. It prints well, feels like ABS, smells like PLA when printing, and I can use PLA temps on my printer. It sands better than PLA, and if I I hadn't noticed the PLA+ sticker, and the smell, I would think it was ABS. It will break its line into my printer like PLA does; ABS doesn't break if left alone. However, PLA+ lasts longer than regular PLA before breaking.

Getting info from the Internet

Aside from a few discussions on reddit (review, commercial introduction), I can't find anything about it.

Getting info from the Manufacturer

I went back to Microcenter and the guy that was there working the 3d printing section did not know what I was talking about.

I went to Microcenter another time and the guy in the filament area said that all of their PLA filament was now PLA+, and that the + meant it was to be used at a higher temperature. The boxes are labeled with 205 - 225°C. It seems that all the inland brand PLA I have is PLA+, save for the first roll I bought. It does not have any kind of temperature markings on it.

Flash forward 1.5+ years from the original question

This question got some recent attention, so I looked to find the answer again. I found this article, which is a hot pile of !usefulness, giving no data, lots of opinion, and probably some direct insights from someone's marketing department.

These guys say it's good stuff, but nothing about the chemical or compositional difference between the two. When I find people talking about the difference (like on reddit), those are the details usually mentioned, which are vague, anecdotal, and opinionated, and could be clever marketing (could be, not guaranteed to be). One man's shiny is another man's matte for example.

Monoprice confirmed what I already did by reading the label and printing with it, but does mention TPU, which might be Thermoplastic polyurethane. No quantity or proportion or anything, and since they're the only manufacturer/reseller to officially say this, I consider it unconfirmed. One of the answers below says that PLA+ probably includes TPU or something like it, but that's conjecture or opinion by their own admission.

PLA+ is a variation of PLA that has added material in order to make the filament less brittle, have a smoother surface finish, and less likely to absorb moisture. Typically, TPU is added into the filament in order to achieve this property. PLA+ will have the feel and functionality of ABS without the smell. If you didn’t know better, you would think it was ABS. We suggest printing with PLA+ at 205 to 210 degrees Celsius and with a bed temperature of 45 degrees Celsius. PLA+ responds very well to blue painter’s tape and a glue stick to hold properly and not peel up when printing.

These people also ask what it is, but they're doing science about it circa 2014 to try to figure it out.

I'm not sure what to think of this manufacturer/seller's description. It sounds like they are implying that PLA has a branding problem, so they added a plus to it for a new formula to fix their branding.

PLA Plus is an enhanced version of our PLA that's less brittle and more durable. ‘Enhanced’ PLAs have a bad reputation, some are no better than PLA, some perform worse in some conditions. We’ve taken a different approach: our ‘regular’ PLA is regarded as the strongest pure PLA in the industry, it’s hard to improve on the best. But sometimes you need something a little more durable. Enter our specially formulated PLA Plus. Prints like PLA, but with better durability. Its available with their brighter color options!

Final thoughts

I find a lot of articles/posts talking about "eSun PLA+" specifically. I'm starting to think that this might be the OEM and that other companies are selling it with their own branding, but that all PLA+ comes from the same place. I found their product page, and it says this, which mentions nothing about the formula:

Characteristics：

• extracted and purified from corn grain;
• high rigidity, good glossiness and transparency;
• suitable for printing larger models;
• toughness is 2 times more than the PLA on the market;
• no wiredrawing problems, the surface of the printouts will be smoother and more delicate;
• no cracking problem.

Answer 1

Disclaimer: I am not affiliated with any linked brand or company, I just link to them for reference of the suggested print settings.

What is PLA?

PLA is, by its definition PolyLacticAcid, a polymer of entwined lactic acids. It is commonly made from fermenting starch - not via Type I (alcohol) but Type II (lactic acid) fermentation^{user77232, Wikipedia}. Chemically it looks like this:

It's relevant physical data for the pure material are a density of 1.210–1.430 g·cm⁻³ and a melting point of 150 to 160 °C.^Wikipedia.

Usually, PLA sold under just the name PLA contains, besides PLA, additives to change the color from transparent to whatever color one is printing at. This can change the standard printing temperature depending on the amount, size and shape of the pigments embedded (see below).

Common Printing temperatures are listed by the manufacturers in the range of 185 to 210 °C. The color can have an influence on the printing temperature, especially for the difference between transparent and opaque filaments. While a heated bed is not strictly necessary, the bed temperature is usually quoted with 60 °C.

I myself print most PLA filaments at 200 °C and 60 °C bed, but for noncolored transparent filament, I had better results using 190 °C.

Note that not all PLA is just PLA! It is very likely that some PLA brands contain fillers and additives from the house without claiming to be a +-filament, indeed, additives precede the idea of PLA+, as the case with Tiertime PP3DP filaments will show.

The special Tiertime mixture

Since back in 2012 or earlier, ABS made by Tiertime includes some unknown compound (possibly PC) that alters the best-result print temperature from the "normal" 220 - 240 °C to the much higher but narrower 260 - 270 °C band. Why this is done is a mystery among 3d-printing enthusiasts, but it might be either to get rid of any color-dependency of the print results or to make it harder to use generic ABS. Fact is, that this temperature was matching what was set as the (then unchangeable) standard temperature in the Up 1.1.7 software of that time.^{Angus aka MakersMuse & Tiertime Forums}. The higher temperature hasn't changed over the years^{Tiertime ABS}. Indeed, the Tiertime PLA introduced in March 2014^Tiertime is also quoted to print at higher temperatures than generic PLA, and had similarly a higher default temperature in the then updated UP-spftware^{Tiertime Forums}, though I found listings from 200^{here & here} to 215 °C^{here under Technische Daten}.

The modern UP-Studio software allows setting the temperature freely^{Angus aka MakersMuse}.

What is PLA+?

Now, what differs PLA from PLA+? Well, PLA+ is a modified PLA, which means that it has additives in it to alter its properties. What exactly is added depends extremely on the manufacturer, and no two PLA+ are the same.^all3dp.

What is the difference?

PLA+ has - but for a few degrees - the same printing temperature as standard PLA. In fact, the printing temperature difference between standard PLA from different brands is often larger than the difference between PLA and PLA+.

All3dp claims, that most PLA+ would have a better surface finish than the PLA from the same brand. Because of the additives, they also usually print best at elevated temperature compared to PLA. Among various manufacturers, I saw 210–240 °C^{Kodak PLA+}, 190-220 °C^{SUNLU PLA+} and 190-210 °C^{eSun PLA+}.

However, there is no uniformity in other effects on the filament. Some filaments would have less moisture absorption, a different stiffness or compressibility while others might have a higher tensile strength and feature an extremely glossy surface.

Most commonly, the claimed benefits lie in the fields of the filament's strength, surface texture and glossiness, the printability of overhangs.

Conclusion

PLA+ is not one product per se but a family of modified PLA. While you can print PLA+ with the same settings as normal PLA, the resulting benefits between different brands are much more diverse than with normal PLA.

• Changing between different brands of similar quality normal PLA has usually little to no effect on the print's general properties.
• Changing between different brands of similar quality PLA+ can alter the print's properties immensely

Because of the fact that no two brands of PLA+ are the same (and the manufacturers are silent on what additives they use to change the properties), one should not rely on the same effects when switching between brands.

Answer 2

There’s no huge difference between both. The printing settings like temperature and printing speed are practically the same. But the PLA+ have a much better surface quality and it’s slightly more bright than normal PLA. Another difference is that the PLA+ it's more effective in bridges than PLA.

If you want to the comparison between PLA and PLA+ go right here, PLA vs PLA+ (short review). This post is an awesome experiment with both materials.

Answer 3

Some of these questions could be answered by asking manufacturers for MSDS (Material Safety Data Sheets), aka. SDS (Safety Data Sheets).

Under EU laws in place since 2008 any substance shipped into the EEA (European Economic Area) in quantities of more than 1 tonne/year, whose composition contains more than 0.1% by weight of a compound identified in the Article 57 database, must provide an MSDS on request that includes a breakdown of its content.

If you look at the SDS for eSUN's PLA+, for example you see:

╔═══════════════════╦═══════════╦═══════════╦═════════════╗
║ Ingredient Name   ║   CAS No. ║    EC No. ║ Content (%) ║
╠═══════════════════╬═══════════╬═══════════╬═════════════╣
║ Polylactide resin ║ 9051-89-2 ║ 618-575-7 ║          98 ║
║ Calcium carbonate ║  471-34-1 ║ 207-439-9 ║           2 ║
╚═══════════════════╩═══════════╩═══════════╩═════════════╝

Answer 4

PLA+, depending on the brand, is probably a mixture of other plastics (things like TPU¹) to help improve upon the weaknesses of regular PLA like brittleness and moisture absorbing. Or they simply used a higher quality PLA blend to create the filament.

I do not have a specific source except from collaborating with different materials experts such as Essentium Materials. TPU is a flexible plastic that can have different "hardness" levels.

---

¹ Thermoplastic Polyurethane. It's a flexible thermoplastic.

Answer 5

I know this is an old question, but CNC Kitchen just recently did a review of PLA+ and the mechanical properties of one brand, and found it far weaker than plain PLA, but with failure modes that might be mord graceful/preferable for some applications. In short, it stretched and tore rather than snapping.

Answer 6

PLA+ is a marketing term. Where PLA and ABS have specific chemical meanings (more or less... manufacturers already will have different additives or processes), the only real requirement for PLA+ is using some unknown quantity of PLA as a base.

Look at coffee beans as an example: we have Arabica vs Robusta. Arabica is usually considered better, for some definition of "better". (BTW: Starbucks serves cheaper Robusta). The relevant thing here is in many places you only need 10% Arabica content to label and market a coffee as Arabica coffee. The rest of the product could be... well, anything the maker wants to include.

PLA+ is similar. There's no real definitive meaning to it, beyond some measure of original PLA content and the hope you'll believe it's "better", and therefore maybe pay a little more.

The good news is, usually PLA+ really is better... at least so far. But as more people start viewing it as a real step up from regular PLA, it's likely we'll also start to see some shady business people pass off inferior product at PLA+. It's likely this is already happening.

Moral of the story: read the label carefully. And unlike coffee, which is a food and therefore better regulated, filaments have hardly any rules about labeling; there may not be a label to read at all, so be extra careful what you buy.

Answer 7

Adding this as a new answer since it doesn't seem to be covered in existing ones:

Despite "PLA+" being a marketing term without a specific definition, I've found that many (most?) filament vendors don't seem to be doing their own secret-sauce blending to make it, and most premium filament vendors who do document the source polymers they use are using roughly the same thing - most often one of the Natureworks Ingeo 3D series of polymers, obtained in pellet source form, often 3D850 or 3D870. As such, if you can verify that this is what you filament marketed as "PLA+" is made from (or just search out one that's well-documented) you can use the data sheets for the polymer to find out more about how it's formulated.