Game Changing Polypropylene Additives Improve Impact Resistance and Processing Costs

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Milliken’s DeltaMax performance modifiers for polypropylene can dramatically enhance the material’s impact resistance or melt flow rate, or improve both simultaneously.


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Milliken DeltaMax polypropylene performance modifiers

Many plastics processors and product developers consider polypropylene (PP) a workhorse resin but are equally aware of its limitations. It’s a good low-cost resin for producing large quantities of relatively simple parts. But products requiring better physical properties require the use of more expensive premium PPs or engineering resins. Moreover, PP’s problems with melt flow and the use of recycled resin make processing the material more difficult and expensive, giving back some of economic advantages of the lower initial cost.

But what if there were a way to improve both the physical properties and the processability of standard polypropylene so that it could serve more applications yet still reduce processing costs? That’s exactly what Milliken is offering with its DeltaMax™ family of masterbatch performance modifiers. The technology enables injection molders to enhance the impact and melt flow of their ICP or rPP resins by adding a masterbatch at machine-side. The net effect is the ability to design parts with higher impact resistance and thinner profiles, run machines with faster cycle times and lower temperatures, reduce the use of costly impact modifiers, and reduce inventory of multiple ICP resins. Additionally, DeltaMax performance modifiers allow for the use of recycled PP at equal or better performance levels compared to virgin resins. This creates an opportunity to improve the circular economy and promotes more sustainable manufacturing practices.


How it Works

Described as a novel reactive extrusion modifier, DeltaMax is a radical advancement in additive technology for PP impact copolymers (ICPs) as well as recycled PP. The problem with polypropylene has been that it doesn’t provide a good balance between high impact resistance with stiffness and melt flow, making it difficult to cost-effectively formulate, design, and process higher functioning parts. This is particularly the case for recycled polypropylene resins, which typically lack high melt flow and impact properties required for many injection molded applications within consumer, industrial, and automotive markets.

How Milliken DeltaMax works

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What DeltaMax does is to mitigate those limitations with substantially improved melt flow, higher impact parts, and often both. What’s most important for the application will determine which grade of DeltaMax to use.

The additive increases impact strength by as much as three times by optimizing rubber dispersion and domain size (see graphic). This higher impact performance allows processors to decrease rubber content to reduce weight and costs. If a low impact ICP (with low rubber content) is suitable for the application, for example, DeltaMax can increase the melt flow rate as much as five times without sacrificing impact resistance. The material now becomes much easier and less expensive to process. With a medium- to high-impact PP grades, the additive converts the rubber to smaller, more evenly distributed domains to improve impact properties, yet still is easier to process. There are many other applications where processors are looking to improve both properties, and there is a DeltaMax additive for that too. More on this later.


The DeltaMax Value Proposition

By simultaneously improving both impact and melt flow in PP impact copolymers, DeltaMax enables processors to make parts stronger, lighter and faster than before. The technology results in three major cost benefits:

Cycle Time Reduction — Decreasing resin viscosity speeds first stage injection for quicker filling of the mold. With higher melt flow, processing temperatures can also be reduced which decreases cooling time in the mold. The combination of faster fill and quicker injection results in an average productivity improvement of 10%. It also means you can produce more parts with less energy.


See how DeltaMax reduces cost by improving melt flow.


Resin Consolidation — Custom processors use a variety of PP grades for different products. Low cost resins are fine for simple parts, but a more expensive premium grade will be required for parts with better physical properties. With DeltaMax the properties of the less expensive resin can be upgraded to match the premium resin. This reduces the number of polypropylene grades a processor needs to purchase and store. Using fewer, and lower cost resins lowers total material costs.


DeltaMax enables injection molders to make more products with fewer resins.


More Recycled PP — Recycled PP is inexpensive, but its physical properties and processability are poor which is why it generally can only be used in combination with a larger ratio of virgin resin. DeltaMax boosts the properties of recycled PP making it equal to or even better than virgin resin. That means processors no longer have to blend multiple resins to get the necessary part properties. Processors can even make parts with 100% recycled PP resins. This ability further reduces costs while achieving a level of sustainability that was not possible before.


DeltaMax enables much greater use of recycled PP resins.

DeltaMax Grades

How effective is DeltaMax? As the graphs below show, this additive offers multidimensional improvements to PP performance and processability. There are three grades of DeltaMax masterbatches designed to primarily target impact enhancement, melt flow improvement, or both. They are:

Milliken DeltaMax grades


DeltaMax i300 Impact Enhancer — Maximizes impact performance while optimizing melt flow rate.

DeltaMax a200 All Purpose Modifier — Provides a strong balance of impact, stiffness, and melt flow rate.

DeltaMax m100 Melt Flow Modifier — Increases the melt flow rate while providing equal or better impact performance.


Proven Performance

There are a number of documented case studies where DeltaMax has rendered dramatic improvements to injection molded products. Here are three good examples:

plastic impact properties

Maximize impact propertiesAn industrial bucket and pail manufacturer was attempting to formulate a high-impact, non-break solution to meet new specifications for a 3.0m drop test. Complexity in formulation and the high cost of impact modifier additives resulted in limited options in the market. With DeltaMax i300 Impact Enhancer they were able to take a conventional low to medium impact copolymer and move the impact rating from 13 to 43 (a 3X improvement) and double the melt flow rate. More.

polypropylene melt flow properties

Optimize melt flow properties A housewares manufacturer wanted to optimize operating efficiencies by lowering run temperatures and increasing processing speed. Their molding equipment runs 24/7 at full capacity, which limits line expansion with new and existing customers. With DeltaMax m100 Melt Flow Modifier they were able lower molding temperature from 425° F to 400°, reduce cycle times by 11% and also reduce CO2 emissions by 7%. More.

polypropylene impact and melt lfow properties

Improve sustainabilityBased on a new sustainability initiative, a leading converter in the home improvement category was tasked with increasing the amount of recycled plastics being used without sacrificing physical properties. With DeltaMax a200 All Purpose Modifier they were able to use 100% recycled resin (vs. 20% previously) to mold a paint tray, yet achieve a 20% improvement in impact strength and 2.5X gain in melt flow rate. More.

These are but a few examples of how DeltaMax has changed the economics of processing polypropylene. It enables stronger and stiffer end products, lower processing and material costs, and more sustainable manufacturing practices. That’s a package of benefits PP injection molders can’t afford to ignore.

Go here for more information on DeltaMax performance modifiers for polypropylene.