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Dr. Dennis L. Krueger, a 3M corporate scientist, is recognized for his leadership in the development of coextrusion and polymer blend technology and for his innovative application of these technologies to many 3M products.  He had an influence on products you are likely to have purchased in the past 20 years: a cell phone, laptop, television, or diapers.

He has 70 patents, a remarkable patent history because they are in nine different technologies: (1) liquid and liquid separators, (2) radiation resistant polypropylene, (3) piezoelectric and pyroelectric films, (4) polymer blends, (5) bicomponent microfibers and webs (used in bandages), (6) micro-layer polymer films by coextrusion, (7) new film orientation equipment (technology used in tablets and smart phones), (8) micro porous films, and (9) elastic films.


He was known as the “Father of Coextrusion” by his colleagues at 3M.  He championed the application of the coextrusion process and introduced multilayer coextrusion feedback technology to 3M.  This foundational work contributed to hundreds of inventions across the company’s various businesses. 

Coextrusion is the process of extruding two or more plastics through the same die.  Coextrusion is all about melting and reforming plastics.  A number of plastic substances or polymers are heated separately and then joined together before being molded into the required shape.  Because some plastics are not a strong, durable, or weatherproof as others, using a combination of material is the best way to meet the needs of a product specification.  

The advantage of coextrusion is that each material used maintains its desired characteristic properties (such as stiffness, impermeability, or environmental resistance), which would be impossible to attain with any single material.  When multiple plastics are combined, the result yields properties distinct from those of a single material. These films can have many layers to them.  

Coextrusion produces a plastic film containing two or more distinct plastic layers without requiring any intermediate steps – in contrast to lamination, where two or more plastic films are produced first and then adhered together.  In lamination, each of the films being joined must be thick enough to be produced and handled on its own.  In coextrusion, the layers of each plastic can be extremely thin.  Since the structure is handled only as a unit, there is no need for the individual layers to be self-supporting.  Thus, coextrusion often permits considerable cost savings when multilayer flexible materials are desired. 

Krueger’s innovations with coextrusion technology are widely used around the world today.  For example, optical films applied to smartphones use coextrusion technology to make what’s on the screen easier to read.  Similarly, diaper tape that has a highly elastic inner layer and strong outer layers uses coextrusion technology; as do certain industrial tapes, first aid dressings, oil absorbing cleanup products, and personal respirators. 

He was an early innovator in multilayer plastic films.  He created a key invention that allows 3M to produce a high-performance optical film.  This film became a standard product commonly used in smart phones and tablet computers.  
He was a co-inventor of a new film-stretching machine that imparts unique properties on multilayer films.  His creation was critical to developing an entirely new platform of LCD enhancing film.

He had success in such areas as development of coextruded films for unique tape backings for industrial applications, as well as non-woven technology for personal safety products (respirators), room air purifications (Filtrete™ filters), and environmental cleanup (oil sorbent).  
He invented the soft elastic film to meet the need for a processable diaper elastic.  His concept of forming a soft microtextured elastic film by stretching a three-layered film was developed with the help of many others.  As reported by Matthew Lambert of the Hudson Star-Observer, Krueger says one of his greatest inventions was the elastic film in a diaper, as far as novelty: “It’s elastic like a rubber, but not tacky like a rubber . . .  it is silky smooth.”  Krueger says he remembers the night he and his colleagues finally created the elastic film.  He called it a “eureka moment.” 

Krueger has been described as one of the best “idea generators” within 3M.  He gathered ideas from his many interests and associations to come up with new ideas for different products based on everyday needs he would see or hear about.  He had a knack for combining his understanding of the product need with some way of bringing an existing technology or developing a new technology to meet that need. 
After inventing the technology, he identified applications, led development efforts, and championed new businesses within 3M.  He worked with a wide variety of groups in multiple markets to develop and implement new technology for 3M. 

In each area, Kruger demonstrated an outstanding visionary ability to understand the key challenges, to recognize the need for new solution, and to pro-actively engage individuals from across 3M early in the project.  With his multiple successes, he gained the trust and support of many technical and business leaders throughout 3M.  His willingness to champion ideas from conception all the way into the marketplace helped build more than $1 billion sales for 3M during his career.  

His work went well beyond the long list of inventions and patents.  His intangible qualities led many others to successful careers, served as a catalyst for new product and invention opportunities, and brought 3M scientists into a collaborative relationship with other scientists and professors.  He believed it was important to bring people together to discuss, explore, and advance polymer physics.  He established the annual 3M Polymer Physics Symposia to promote interaction between 3M scientists and other industrial and academic researchers. 
He was born in Merrill, Wisconsin.  Shortly after receiving his doctorate in material engineering from the University of Michigan, he began working for 3M in 1972, a career that would span almost three decades.  He retired in 2001.
Going to work as a scientist for a diverse company like 3M was an easy choice, according to Krueger, with the opportunity to research anything he was interested in.  “I could do anything I wanted to,” said Krueger.  “There was always some technology that would be of interest to me.” 

Krueger was famous for working with new engineers, developing and nurturing them.  He had the ability to stimulate those around him to pursue their ideas.  His mentoring of other researchers led to significant contributions throughout the company.  He willingly gave credit where it was due, evidenced by the fact that only 2 of his 70 patents list him as the sole inventor.
His nominators suggest that at the top of the list of his inventions should his greatest invention: a list of names of the inventors he helped create.


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