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FoamConverting

MOLDED PULP PRODUCTS

 

Molded pulp products got their origin from the paper industry, where cellulose fiber is ground up in a slurry of water having about 25% solids and pumped in a mold having perforation small enough to keep the fiber in and large enough to let the water out.  

 

There are three general types of molded pulp products, the first being conventional molded pulp, also known as type 1, where products like egg cartons are produced on a machine having a cylindrical series of molds that continuously fill and form the product into a shape, then dried in long belt type driers.  The surface condition of the product can be oatmeal like. Typically, commercial pulp parts are molded from recycled paper and/or corrugated clippings.

 

The second general type is dry pressed molded pulp, also known as type 2, where the same process as conventional can be employed, then the product is partially dried after molding. The next step is to press the fiber into a precise shape making the surface condition smoother than conventional parts.  The pressing operation also allows for adding logos and nomenclature to the part.  The part is then completely dried and trimmed, as necessary. Typically, dry pressed parts are molded from corrugated clippings, the material can be virgin or recycled fiber.

 

The third general type is wet pressed or thermoformed molded pulp products, also known as type 3.  Unlike the first two types, thermoformed parts are produced under heat and pressure to form a product completely dry after molding.  The parts are trimmed, and holes die cut as necessary once they come out of the molding machine. Typically, thermoformed products are molded from fibers such as bamboo, bagasse (sugar cane after harvesting), and eucalyptus.  Thermoformed products have a smooth, paper-like finish.  One side of the product will have a gauzy finish due to being in contact with the screen side of the mold which lets the water evacuate from the mold.  In the product design phase, we do not care which side of the product is gauzy, the customer can choose.  Please see our product design criteria below:

 

DESIGN CRITERIA:

  • Over all Design Dimensions max. 600 mm (23.62”) x 914.4 mm (36’’) x 150 mm (5.9’’)

  • Cavity mold draft: 7 degrees draft max., short wall draft could be 5 degrees.

  • Living hinges can be designed in

  • Apertures/holes require a tool for each plane

  • Radius – no less than 3 mm (0.12”)

  • Steep valleys and troughs are over fill areas

  • Wall thickness – 0.8 mm (0.0314”) to 1.2 mm (0.0472”) max.

  • Tolerance 1 mm +/- .2 mm

Foam Converting​

A G S Co.  Converts the following foams:

Polyethylene; Polyurethane (ester; and ether ); Cross-links Polyethylene.

The services we provide are:

  • Sheeting to very precise thicknesses 

  • Die-cutting; water jet cutting

  • Laminating with adhesive and heat welding

  • Custom case  inserts

  • Custom package design

  • Protective packaging design

  • Kiss cutting

  • Agricultural packaging

  • Contract manufacturing

  • Foam End and Top Cap.

APPLICATIONS

  1. Protective packaging

  2. Custom case inserts

  3. End caps

  4. Athletic equipment

  5. Medical Products

  6. Filters (Reticulated Foams)

  7. Anti-static foams

  8. Static Dissipative Electronic Packaging

  9. Instrument Packaging

  10. Optical instrument Packaging

  11. Sales cases

  12. Cushion Packaging

  13. Crate insert foam

  14. Trays

  15. Pads

  16. Sheets

Frequently asked questions

What does the "Density" of foam mean?

What is "Indentation Force Deflection (IFD)"?

What is " Compression Load Deflection(CLD)"?

What is "% compression set"?

What is " tensile strength"?

What is " elongation"?

What is " tear strength"?

What is " clickability"?

What is " board foot" 

What is " Reticulated" Foam?

Learn about Adhesives

 

Q. What does the "Density" of foam mean?

A.  Density is the measurement of the mass of the foam in pounds per volume in cubic feet.  So, the density of the foam is expressed in pounds per cubic foot.  Density is not a measure of firmness, stiffness,  pore size, or load-bearing capacity.  If you cut a piece of foam that is supposed to have a density of 1.7 pounds per cubic foot (PCF) into a 12" x 12" x 12" block, it will weigh 1.7 pounds.   Density can be obtained from any sample size.

Q. What is "Indentation Force Deflection (IFD)"?

A.  Previously known as ILD is one test method to determine load bearing capacity(firmness or stiffness) and is expressed in pounds of force per 50 square inches, at a given percent deflection of the foam.

Q. What is " Compression Load Deflection(CLD)"?

A.  CLD is a measure of parameters and is expressed in pounds per square inch(psi), at a given percentage deflection.

Q. What is the "% compression set"?

A.  Percent compression set is a measure of the permanent deformation of foam after it has been compressed between two metal plates for the control time period and temperature condition.  The standard conditions are 22 hours at 70o C (158o F).  The foam is then compressed to a thickness given to its original thickness that remained given as a percentage of its original thickness, usually 50%.  Compression set is expressed as the percentage of its original thickness that remained "set".  For example: if a 2"  x  2"  x 1" sample measured 1.00 or inch before compression and 0.95 inches after the test, it is reported to have a compression set value of 5% i.e., it did not recover 5%of its original thickness.

Q. What is " tensile strength"?

A.  Tensile strength is the measure of the amount of force required to break a 1/2"  square inch area of foam as it is pulled apart. Tensile strength is expressed in pounds per square inch (psi)

Q. What is " elongation"?

A.  Elongation is the measure of the extent to which the foam can be stretched before it breaks and is expressed as a percentage of its original length.  Elongation is measured at the same time, as tensile strength is determined; therefore, the sample size is the same.

Q.What is " tear strength"?

A.  Tear strength is a measure of the force required to continue a tear in foam after a split has been started in is expressed in pounds per linear inch (pli).

Q. What is " Clickability"?

A.  This is the rating of a foam's ability to recover from a die-cutting operation. Foams are rated as having a good, fair, or poor click property.  Click is tested on a one-inch piece of foam by die-cutting a tensile specimen. Then observing the initial recovery, and its recovery after one minute. What is observed is the sharpness of the edges of the tensile part and the one-inch foam sheet and it was cut from.  Also, the height recovery after the compression of the die-cutter is noted

Q. What is " board foot" "

A.  Foam is measured in board feet.  A board foot of foam is equal to a 12" x 12" x 1" piece of foam and is equal to 1/12 of a cubic foot of foam. This is the commonly used measure in the foam industry.

Q. What is " Reticulated" Foam?

A. Reticulated foam is characterized by a three-dimensional skeletal structure with few or no membranes between strands. Reticulated foam is generally used as filters, acoustical panels, and for controlled liquid delivery. Reticulated foam is sometimes referred to as filter foams.

ADHESIVES

Hot Melts

Ethylene vinyl acetate (EVA) hot melts are the most common variety, having good adhesion to many substrates.  The EVAs are the lowest cost and have a wide range of open times and have the poorest temperature resistance.

Polyamide hot melts are higher in cost, higher performing adhesives with excellent high temperature resistance, up to 3000 F.  

Polyolefin hot melts are specially formulated for adhesion to polyolefins such as polypropylene and polyethylene plastics.  Compared to other hot melts, polyolefins have a longer open time and have excellent resistance against water, methanol, and acetic acid (polar acids).

Reactive polyurethanes (PUR) are supplied as a urethane prepolymer, which reacts like a standard hot melt until it cools.  Once the PUR cools, it reacts with moisture over time to crosslink into a tough thermoset polyurethane.  PUR’s have a lower dispensing temperature, higher adhesion to metals and improved temperature resistance.

Water-Based

Water-based or waterborne adhesives are typically formulated from two groups:

Natural polymers, such as vegetable sources, protein sources, and animal sources.

Soluble synthetic polymers, such as polyvinyl alcohol, cellulose ethers, methylcellulose, and polyvinylpyrrolidone.  The later of the two formulations make up most of today’s products.

The strength of waterborne adhesives is achieved when water is lost from the glue formulation by evaporation or absorption by the substrate.  One of the substrates must be porous to allow for absorption.

Urethanes

Polyurethane adhesives are a two-part system, mixing can be a 1:1 ratio and up to a 1:4 ratio.  Polyurethane adhesives bond a wide variety of materials, including most metals, plastics, and composites.  Polyurethane adhesives exhibit superior moisture and humidity resistance, as well as good toughness and flexibility.

UV Curable

Light cure adhesives are a one component, no mixing product that cures extremely fast for immediate QC in high volume assembly operations.  Excellent bond strength to plastics and glass, bond on-demand capability for unlimited repositioning.  Dual cure formulations are available for curing substrates where light cannot reach.  Typically, light must be able to reach the entire bond-line through a transparent substrate.

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