pDCPD MOLDING

pDCPD Molding Services

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Polydicyclopentadiene (pDCPD) is an engineered thermoset polymer possessing an excellent combination of chemical and corrosion resistance, stiffness, impact strength, and heat resistance. pDCPD delivers the molding flexibility of a thermoset, but with characteristics similar to expensive engineered thermoplastics.

Osborne has over 20 years of experience molding pDCPD and molds parts using a range of Telene® DCPD resins with a wide range of Reaction Injection Molding (RIM) equipment to meet your most demanding production requirements. We bring technical expertise in pDCPD chemistry, a fully equipped and highly trained staff of pDCPD specialists, and the skills of dedicated craftsmen to help transform your engineered plastic concept into reality.

Overview

pDCPD is prepared by polymerizing low-viscosity DCPD monomer in low-pressure processes that enable the use of low-cost molds and fast cycle times. Low-viscosity means that pDCPD gives excellent replication of surface features for aesthetically demanding applications. Additionally, pDCPD gives superior paint adhesion and durability for appearance parts. pDCPD is used on numerous other applications wherever large, tough, corrosion-resistant, and aesthetically pleasing appearance is required.

The design freedom of pDCPD has virtually no limitation on part size or weight. Parts with thickness from 0.100-inch (2.5 mm) to 12-inches and with a surface area from 1-ft2 (0.1-m2) to 140-ft2 (13-m2) are made successfully. Parts with variable wall thickness and molded stiffening ribs are possible. Molded bosses and fasteners reduce secondary assembly operations. Good adhesion and machining quality extend the usefulness of pDCPD parts.

pDCPD is widely used for:

  • Large truck and bus body panels
  • Instrumentation housing
  • Equipment parts in agriculture
  • Large waste containers
  • Recreation parts
  • Domestic wash basins and shower stalls
  • Construction equipment parts
  • Water treatment equipment
  • Conveyor trays
  • Fan shrouds
  • Shipping containers
  • Septic tanks
  • Corrosion-resistant chemical process equipment
Benefits

The benefits of molded polydicyclopentadiene (pDCPD) include parts with:

  • High tensile strength
  • High impact strength
  • Moderate flexural properties
  • Migh heat distortion temperature
  • Excellent corrosion resistance

The flexibility of adding several additives can be added to the liquid DCPD monomer to create specialized resin formulations that give the final polymerized material a wide range of mechanical properties and characteristics including:

  • Flexibility
  • Rigidity
  • Flame retardance
  • Pigmentation
  • Abrasive resistance

Corrosion resistance is another beneficial characteristic of pDCPD, which has been used in the chlor-alkali industry for more than 20 years.

Definition

Thermosets like pDCPD are distinguished from thermoplastic materials, the other main group of plastics, because, unlike thermoplastics which revert back to liquid form under excessive heat, thermosets will remain in a post-cured form. pDCPD and other thermosets resist melting because of the process by which they’re created: Two dissimilar liquids are mixed together, creating high temperatures that foster cross-linking between molecular chains. This cross-linking contributes to thermosets’ heat resistance.

RIM-molded pDCPD parts are created through a process that begins when two liquid reactants – an isocyanate component and a polyol resin mixture – are held in separate tanks at an elevated temperature with agitators. These liquids are fed through supply lines at high pressure to the mixhead.

When the injection begins, valves open in the mixhead and the liquids enter a chamber in the mixhead at high pressures (usually between 1,500 and 3,000 psi) and high speeds. Here they are mixed by high-velocity impingement. From the mix chamber, the mixed liquid flows into the mold at atmospheric pressure and undergoes an exothermic chemical reaction, forming a polymer in the mold.

Reaction time is usually expressed in seconds. For extremely large parts the reaction time can be extended to allow for proper filling of the mold.

Dicyclopentadiene (DCPD), a liquid monomer, is catalyzed by an active metal component via the ring opening metastasis polymerization (ROMP) process. The monomer and catalyst can be mixed by hand or by Reaction Injection Molding (RIM).

We use two different metal-activated catalyst systems that allow for unique mechanical properties, which are customizable for given projects. The liquid DCPD monomer also can be combined with several additives to create specialized resin formulations.

Equipment

Osborne’s pDCPD molding via reaction injection molding (RIM) includes equipment and low-cost composite or aluminum RIM molds that offer the production flexibility you need for your most demanding projects.

We’re pleased to run a wide range of RIM molding equipment, including:

FAQ
What is the difference between Injection Molding and Reaction Injection Molding (RIM)?
Injection molding is a process where a thermoplastic polymer is heated to its melt temperature and injected into a mold at high pressure and rapid flow rate. The injected polymer is then cooled to point where the part has enough green strength to be removed from the mold. Reaction Injection Molding is a process where two different liquid polymers are simultaneously mixed and injected into the mold. The two liquid polymers react with one another to form a solid polymer. The reaction between the two liquids is exothermic in nature and requires this excess heat to be removed from the mold during the injection process.
Is the viscosity of thermoplastic injection molding polymers greater than the reacting liquid polymers injected using the RIM process?
Typically yes. Most RIM molded polymers have viscosities between water and a thick syrup whereas melted thermoplastic polymers have a viscosity similar to soft taffy.
What problems occur with high viscosity polymers that are injected into a mold?
Polymers, liquid or semi-solid, with a high viscosity that are injected into a mold tend to create higher internal mold pressures. There is a direct relationship between viscosity and internal mold pressures. Higher internal mold pressures require the mold to be made of higher strength materials such as steel or heat treated steel.
What type of mold is used for low viscosity polymers used in the RIM process?
RIM molded liquid polymers with low viscosities can be molded in medium density foam (45 pcf and greater) molds, composite molds (epoxy, polyester, etc), and aluminum. The injection of low viscosity polymers result in lower internal mold pressure which requires less strength mold materials.
Can all RIM molded polymers be molded in "soft" composite molds?
No. There are other factors that determine the best type of mold construction. These factors include the injection rate, the molded part size and configuration, and the peak exothermic temperature of the polymerization process. If the injection rate is too great for the mold size and configuration, internal restrictions within the mold will create back pressures that may be greater than the strength of the material used to construct the mold. Likewise, if the exothermic temperature is too great, the mold surface may begin to deteriorate resulting in poor molded surface quality.
What advantages does RIM molded polymers have over Thermoplastic polymers used in Injection Molding?
RIM molded polymers have the major advantage of being capable of molding very large parts owing to the ability of modifying the reactivity of the reaction. The extended reactivity allows the polymer to remain in a liquid state longer allowing a large mold cavity to be filled before the chemical reaction is complete. The longer reaction time also creates lower internal mold pressures so that "soft" composite tooling can be used for prototype and lower production applications. The lower internal mold pressure also requires less clamping force to hold the mold closed during the injection process. General internal mold pressures for RIM are 10.3 kPa to 1.4 MPa whereas injection molding will have internal mold pressures ranging from 3.4 MPa to 10.3 MPa.