Antiblock Materbatches are added to films and bags to keep the sheets from sticking together
Anti-block Additives, such as the Crodamide range, reduce blocking at the surface of polymer films and other plastic articles to allow easier processing and handling. Blocking is related to slip, however, slip involves the sliding of two surfaces over each other, blocking is the adhesion of those surfaces. Our anti-blocking additives reduce surface friction allowing easier separation of polymer surfaces. This can give an advantage in end-use applications such as opening plastic bags.
The standard method for testing blocking between layers of plastic film is ASTM 3354-89. By this method, the film-to-film adhesion is expressed as the load (in grams) required to separate two layers of polyethylene film. The test is limited to a maximum load of 200 grams. This is measured by a balance-beam type system similar to an analytical balance. One sheet of film is attached to a block suspended from the end of the balance beam. The other sheet of film is attached to a block fastened to the balance base. Weight is added equivalent to 90 + 10 g/min to the other side of the beam until the two films fully separate, or until they reach 1.905 cm separation.
The standard test method for testing COF is ASTM 1894. This method covers the measurement of static COR which is related to the force required to begin movement of the surfaces relative to each other, and kinetic COF, which is related to the force required to sustain the movement. Film-to-film values are measured by attaching a film to a stationary sled (a 200 gram weight), and attaching another film to a moving plane. These two films are then pulled across each other at a specified rate (6 inches/min). The force measured (in grams) is then divided by the weight of the sled, to yield a dimensionless number between 0.0 and 1.0.
Commercially important Anti-block Additives can be broken down into inorganic and organic types.
These are non-migratory additives useful for high temperature applications since they melt at much higher temperatures than typical polyolefin extrusion temperatures. The particle size and shape of the additive (as well as quality of dispersion) play a key role in determining its antiblocking efficiency. Proper selection of additive type depends somewhat on the gauge (thickness) of the film. Inorganics are relatively inexpensive and best positioned for large volume, commodity-like applications.
Organic antiblocks are migratory in nature and are thought to crystallize on the film surface, forming interfering layers between the adjacent film layers. Organic antiblocks are of interest in high clarity films and “release” applications (e.g. for rubber bales or sticky food items). Sometimes the terms “organic antiblock” and “release agent” are used interchangeably. As a general rule, organic additives are orders of magnitude more costly and therefore of greater interest in higher value-added applications.
Three concentrates were chosen to be incorporated into the film for the study:
1.20% DE in an LDPE carrier.
2.50% talc in an LLDPE carrier.
3.70% CaC03 in an LLDPE carrier.
Films were blown on a Killion lab-sized film line adding these masterbatches at a rate to yield 2500, 5000,7500, and 10,000 ppm of the antiblock in the final film. The CaC03 was also evaluated at 20,000 ppm (2%).
The concentrates were letdown in a blend of 75% 2 Ml octene-LLDPE/25% 2MI LDPE. Both resins were barefoot. The films were all blown at an approximate thickness of 0.8 – 0.9 mils.
Blocking force was measured as described above using ASTM 3354-89.
Figure 1. Antiblocking Effectiveness as a Function of Antiblock Type and Level
As Figure 1 indicates, irregularly shaped DE and talc outperform the smaller, more spherical particles of CaC03. While calcium carbonate proved to behave as an antiblock vs. the control film, it is apparent that much greater levels (250-300%) are required for performance equivalent to DE and talc. This would be expected to increase haze (reduce clarity) as well as possibly deter from physical properties of the film. More studies have been conducted to better understand the role of these inorganics in optical and physical properties of films.
Anti-block Additives In Market
The global antiblock additive market was valued at USD 839.3 million in 2016 and 1,500 usd million by 2021, at a CAGR of 5.7% during the forecast period. The growth of the antiblock additive market in the next five years is projected to be the highest in Asia-Pacific, and the Middle East & Africa. Growing food and pharmaceutical packaging, along with increased focus on agricultural output in the Asia-Pacific region is projected to fuel the demand for antiblock additive.
Based on product type, the antiblock additive market has been segmented into organic and inorganic. The antiblock additive market is led by the inorganic segment, in terms of value, mainly due to its cost-effectiveness and ease of availability.
Based on polymer type, the antiblock additive market has been segmented into LLDPE, LDPE, HDPE, BOPP, PVC, and others. The LLDPE segment is estimated to account for the largest share of the antiblock additive market in 2023, in terms of value. LLDPE polymer type is preferred by plastic film & sheet manufacturers due to its low cost, high tensile strength, and easy applicability in almost every application.
Based on application, the food packaging segment is expected to grow at the highest CAGR, in terms of value, during the forecast period due to increasing consumer awareness for convenience and ready-to-eat packaged food. The increasing disposable income of people and their high spending power has led to high demand for packaged food.
Asia-Pacific is projected to be the fastest-growing antiblock additive market, in terms of value, during the forecast period due to rapidly growing packaging application, in countries such as Japan, India, and South Korea. Furthermore, improving economic condition and infrastructural developments are primarily responsible for high demand for antiblock additive. In addition, increasing focus on improving agricultural output has led to increased use of antiblock additive in the region.Anti-block Additives In Plastic Industry
Packaging is a process for preserving and protecting the quality and shelf-life of different products, such as electronic goods, medicines & drugs, processed & semi-processed foods, and hardware items. The major drivers that aid the growth of the packaging industry are rapid urbanization, changing consumer lifestyles, economic trends, rising health awareness among the different classes of consumers, and development in packaging material & technology. The various properties of plastics, such as durability, low cost, resistance to corrosion, water & chemicals, and low thermal conductivity, make it suitable for use in various applications. The rise in the use of plastics in heavy and light packaging drives the demand for antiblock additive in various end-use applications in the packaging segment.
In the non-packaging applications, antiblocks find its use in various segments such as agriculture films, medical, and paints & coatings. The usage of plastic films is rising in agriculture to combat the increasing pest menace. High manufacturing cost of modified agricultural films with special characteristics such as UV ray protection has caused the prices of films to rise. Consequently, revenue earned from such films has risen globally as well. The North American and European markets are expected to remain saturated, and thus the market for films is expected to grow at a slow pace. Moreover, the increasing construction activities in the developing nations such as China, India, and Brazil are the key drivers of the growth of plastic films, leading to an increase in the use of antiblocks used in such films.