Resin Transfer Molding (RTM)

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Release Agents & Molding Aids Developed Specifically for Improving Your RTM Process

The family of closed-mold processes used in Resin Transfer Molding (RTM) hold various challenges related to the releasing of molded items and to the maintaining of molding and tooling. These challenges can easily have a negative impact on your production efficiency, scrap rates, and investments in molds and tooling, all of which make your job harder and your organization less profitable.

Based on shop-floor experience and extensive laboratory development, Chem-Trend creates dedicated products that are specially formulated to withstand the rigors of RTM processes, such as those used in your molding shop. These RTM oriented products provide you with the best opportunity to gain efficiencies, reduce costs, and improve the HSE aspects you face in your composites molding operations. Specialized release systems consisting of cleaners, primers, sealers, and top coats (release agents) have been developed to ensure that your molds are fully protected and can provide multiple releases. Your experience with the RTM process probably shows that the transferred/injected resin in applications where no gel coat is used often leads to a “washing action,” which increases the labor necessary to keep production moving. Chem-Trend’s specialized release system products are designed to not be disturbed by the “washing” trait of the RTM process. In some cases, these release systems can additionally be augmented with an internal release agent to gain further productivity benefits to the RTM process.

Designed to enhance your RTM process, and your overall operations, our Chemlease® and Zyvax® semi-permanent release system components include:

Mold Cleaners – Removing contaminants from the mold surface prior to initiating the molding process is a key factor in your ability to mold high-quality parts. It not only reduces the potential for imperfections in the final piece, but it also helps ensure a proper bond of the other release agent system components, thus lengthening the time in which they can perform their intended function and reducing your time and labor to produce more parts. Mold cleaners can also be used between cycles to remove minor buildup, before it amplifies into larger problems, leading to scrapped parts or downtime for a more extensive mold cleaning.

Mold Primers – You and your organization know the value of your molds. Without your molds you can’t produce: they are essential for your operational efficiency and profitability. Mold primers provide the ultimate mold protection for most composite molds and are especially useful for B-side/counter-molds used in Light RTM (LRTM), where resin is in direct contact with the mold (no gel coat). Mold primers create an abrasion-resistant film, which renews worn molds and protects new ones. The primer also enhances bonding of the semi-permanent release agent (top coat) to the composite mold, enabling easier demolds and less frequent application of the release agent.

Mold Sealers – Mold sealers are intentionally designed to reduce buildup and mold fouling, which reduce your operational efficiency by causing work stoppage for mold maintenance. These sealers enhance the natural chemistry of the molding process, purposefully reducing the normal tendency of the composite material and the mold to want to bond with each other. By reducing the tendency to bond you will experience less buildup and less mold fouling. Within the RTM process, mold sealers are used in two distinct ways that add value:

  • First, they seal microporosity that is found on mold surfaces while simultaneously preserving a cosmetic, high-gloss mold finish. This makes mold sealers useful for sealing A-side (cosmetic) molds and in areas where gel coat is used.
  • Second, mold sealers are a better choice than primers for specific RTM applications, such as when treating metallic molds, which are more often used in traditional and high-pressure RTM (HP-RTM).

Release Agents (Top Coats) – The semi-permanent family of release agents that Chem-Trend has designed for RTM offers you options for flexibility in both application technique and release characteristics to address your operational needs:

  • High or low slip, depending upon the shape of your mold and molded part
  • Heat or humidity curing, depending on the mold temperature and your local environment
  • Minimal transfer to support post-mold operations such as painting and secondary bonding
  • Flexible application methods while retaining a cosmetic finish:
    • Wipe-on, wipe-off application method, which helps to keep molds clean the longest
    • Wipe-on, leave-on application method, which gains greater importance the larger the mold
    • Spray-on, leave-on application method is an ideal technique for:
      • Application onto B-side molds suspended in the air
      • Application onto hot molds to retain the cosmetic finish

Internal Release Agents – Internal release agents are specially designed additives that are pre-mixed with the resin prior to molding. During cure of the resin, the internal mold release undergoes a phase of separation and will bloom to the surface of the molded part, creating an outer lubricating layer. Internal Mold Release (IMR) isn’t right for all RTM applications, but for certain ones it enhances the process by further minimizing the potential for resin buildup while also increasing the number of parts that can be released before reapplication of the external release agent is required. With RTM, internal mold releases have two use cases:

  • When parts are not gel coated, as occasionally occurs with traditional and LRTM, internal mold releases are especially useful in minimizing buildup on mold surfaces of all types.
  • Internal mold releases help to overcome the physical challenges found in HP-RTM processing, where complex metal mold designs are exposed to high temperatures and abrasive forces. IMR’s in this application can significantly aid in minimizing downtime and maximizing throughput.

You get more than just a release system

Composites molding is a challenging business, and RTM is no exception. Every day you are faced with potential obstacles to your production process, potential issues that may impact your shop’s HSE status, and potential situations that can diminish the effectiveness of your people and your resources. We are here to help. Chem-Trend team members are on composite molding shop floors every day, working with customers like you, addressing production issues, solving new challenges.

Let us help you by allowing us to leverage our extensive experience and our incredible research and development team for your benefit.

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