BOPP Film Modifiers: Efficiently Optimize Packaging Performance

Upgrading BOPP Films

BOPP films are extensively used in flexible packaging applications.

In order to fulfill the needs of this very demanding market, hydrocarbon resin-based compositions, modifiers, help to provide a remarkable combination of BOPP film properties such as:

Better barrier performance
Improved stiffness or shrinkage, and
Easier processing

Let's understand these high-in-demand materials deeply, to better focus on emerging applications.

Enhancing BOPP Film Performance Using Modifiers

BOPP film modifiers provide a wide range of benefits such as:

Barrier
Stiffness
Shrink
Transparency
Sealability
Twist retention

Enhanced BOPP Performances using Modifiers

Barrier Performance

BOPP film barrier performance can be increased with the addition of modifiers in the formulation, allowing simplified film structures, which, in turn, have a positive impact on cost. Moisture & oxygen barrier improvements lead to better protection of products sensitive to humidity & oxidation and help to keep fresher products.

Water Vapor transmission rate measures show that Moisture resistance

can be improved by 50% when using modifiers.

Also, Oxygen transmission rate measures show that Oxygen barrier

can be enhanced by 70% when using modifiers.

The optimum addition level from a cost/performance point of view is dependent on the intended end-use application and the required barrier performance.

Mechanical Resistance

Addition of modifiers in PP formulation provides an overall improvement of mechanical properties thanks to a significant increase of BOPP film stiffness and higher elongation at break.

These benefits allow for downgauging opportunities.

1% secant modulus at different addition levels, which is a measurement of film stiffness, shows that:

A substantial increase of stiffness is achieved as a function of modifiers addition level

Measurement of elongation at the break on 21µm BOPP films with and without modifiers shows that:

Higher elongation at break is achieved when modifiers are added in BOPP film formulation

These mechanical properties improvements brought by BOPP modifiers are very useful for many applications, such as overwrap films.

Film Shrinkage

By using modifiers, it is possible to enhance OPP film shrink. As a result, BOPP modifiers can be used in applications where a high shrink capability is necessary, such as shrink packaging and labeling.

Transparency

Polymer additives enhance the optical properties of BOPP films. As a result, a better BOPP film transparency is obtained and haze is decreased. The addition of modifiers can also improve the gloss characteristics of BOPP films.

Sealability

Addition of modifiers in BOPP Films leads to an improved sealability at lower temperatures. The addition of 30% modifiers significantly increases the peel strength of sealed BOPP film.

The addition of BOPP film modifiers into the core layer of coextruded films leads to an improved sealability at lower temperatures. Lower seal initiation temperature (SIT) and higher seal strengths are obtained when using BOPP modifiers. The shift of the sealability curve with about 10°C towards lower temperatures is of great commercial value. It means that the packaging line can be operated at higher speed and further results in energy savings and less heat degradation of the film and the packed goods.

Twist Retention - DeadFold

Introduction of modifiers improves dead-fold characteristics and twist retention of BOPP films. The addition of additives to a BOPP film brings the following benefits:

Up to 75% twist wrap retention
A printable surface
Excellent optical properties such as high gloss and low haze

% Modifiers in the Core	% Twist Retention
0	25
40	65

Recommended product design:

Layer	Polymer	Thick (µ)	Treatment	Comments
L2	PP + 30 to 40 % modifiers	16 - 17	No Treatment	If metallizable, do not add antilock
L2	PP + 30 to 40 % modifiers	16 - 17	No Treatment	Anti stat in the core is optional
L3	Lower SIT copolymer or terpolymer + anti-block + slip agent	1	No treatment	-

Commercial trials have confirmed that BOPP films containing modifiers give excellent candy twist wrap performance due to the combination of improved twist retention and higher stiffness.

Improving Processing Conditions

During film processing, BOPP film modifiers help to increase the extrudability and stretchability of films. In addition, this enables the production of thin films.

Let's identify opportunities to enhance processing conditions with the use of BOPP modifiers in plastics formulation.

Extrudability

One of the major advantages of modifiers in BOPP film is that it enhances melt flow. Indeed, with increasing amounts of additives, the blend becomes less viscous. Thanks to its lower viscosity, the blend modifiers with polypropylene (PP) can be processed at lower temperatures than unmodified PP.

Absolute extrusion temperatures vary from line to line but, melt temperature can be reduced by about 15°C with the addition of 40 wt% modifiers. The suggested extrusion temperature with PP additives is 230°C.

» Find Out Here Commercially Available BOPP Film Modifier Grades Suitable For Extrusion Process!

Stretchability

Temperatures in Machine Direction Orientation (MDO) and Transverse Direction Orientation (TDO) have to be controlled in a rather narrow range to avoid film breaks and obtain a good thickness profile.

The addition of BOPP modifiers, helps the orientation of the film resulting in easier processing:

BOPP/OPP film can be stretched at lower temperature
Reduced film breaks
Better control of thickness profile

Film producers can therefore optimize their throughput and reduce production waste even at addition level as low as 5%.

Thin Film Capability

Significant improvement of BOPP film mechanical resistance can be achieved when using modifiers, leading to downgauging opportunities.

Stiffer film can be achieved with modifiers, even when thickness is reduced by 20%. The use of this innovative additive allows for the production of more square meters of film per ton of raw material while still meeting customers’ requirements.

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Find Suitable BOPP Film Modifiers for Polymers

View a wide range of BOPP film modifiers available in the market today, analyze technical data of each product, get technical assistance or request samples.

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