InGeCt: in mould gel-coating

An innovative environmentally friendly gelcoating technology for composites for marine and wind-turbine applications to reduce VOC emissions, processing time and cost.

InGeCt is a €1.4M project funded by the Framework Programme 7 (FP7) initiative to encourage Research for Small and Medium sized Enterprises (SME). The main aim is to develop an innovative environmentally friendly gelcoating technology for composites for marine and wind-turbine applications to reduce VOC emissions, processing time and cost.

Gel coats are applied to fibre-reinforced composite materials for aesthetic or protection purposes. Styrene is an essential part of these gelcoats, with ~25% of this released during possessing. These styrene emissions cause irritation and neurological effects as well as possibly being carcinogen. One of the biggest negative effects of styrene is the perceived odour both by the workforce and neighbourhoods. As a result styrene emissions are limited under the Solvent Emissions Directive. Although the adoption of closed mould technologies for the production of composite parts have gone a long way to reducing styrene emissions during manufacture, gelcoating must still be undertaken under open-mould conditions as no viable in-mould gelcoating technology is commercially available. We are developing an innovative in-mould gel-coating process, requiring minimal equipment modification (and therefore low capital expenditure) based on the innovative application of low-viscocity gelcoats and a spacer fabric. The proof-of-concept work undertaken to date has this technology has the potential to achieve significant benefits beyond the current state of the art to produce parts that are fit for purpose whilst reducing styrene emissions to <5ppm.

The overall aim of the InGeCt project is to develop technical textiles and gel-coat formulations in combination with process design and optimisation that will enable significant reductions in VOC emissions whilst reducing production times by 18.5% and manufacturing cost by 10.5%. Our technology will therefore be very attractive to composites processors, giving significant economic and societal benefits to consumers and manufacturers. The SME consortium target a significant penetration of the EU market within a 5 year period, achieving direct annual sales of over 100 million. The technology will make a significant contribution to reducing VOC emissions, enabling EU SMEs to meet their immediate and forthcoming legislative requirements.

The project has considered two manufacturing technologies, referenced to traditional Hand-Painted Gel-Coating (HPGC):

  • Resin Transfer Moulding (RTM) using a Double Glass Plate Mould (DGPM) tool for flat plates, and
  • Resin Infusion under Flexible Tooling (RIFT) with bagging film or a silicone counterface for complex components.

and two in-mould gel-coating techniques

  • In-Mould Gel-Coating (IMGC) with a separator fabric, and
  • In-Mould Surfacing (IMS) with a silicone shim.

The complex component mould tool consists of a contiguous pair of inverted tetrahedra surrounded by an annular channel as shown in section in Figure 1 and as a HPGC moulding in Figure 2.

Figure 1: Section through the apices of the double tetrahedron moulding configuration (left) with rotation (right)

Figure 2: HPGC double tetrahedron moulding.

The research has shown significant reductions in styrene levels in the work-place from the adoption of the new technologies, when referenced to hand painted gel-coating, with typical values reported in Table 1 and Styrene (ppm) vs time plots. 

  styrene level flat plate double tetrahedron
IMGC TWA (ppm) 0.24 (-99.7%) N/A
IMGC Ceiling (ppm) 36 (-96.5%) N/A
IMS TWA (ppm) 0.23 (-99.2%) 0.37 (-98.7%)
IMS Ceiling (ppm) 49 (-92.6%) 107 (-84.0%)
HPGC TWA (ppm) 71 29
HPGC Ceiling (ppm) 1017 668

Pre-project and parallel publications

AR Harper, J Summerscales and N Brooks
Production of composite mouldings
GB Patent Application 2432336, 2007.

J Summerscales, C Hoppins, P Anstice, N Brooks, J Wiggers, D Yahathugoda, A Harper, C Wood and M Cooper
In-Mould Gel-Coating for Resin Transfer Moulding
FPCM-10, Ascona - Switzerland, 11-15 July 2010.

B Muralidharan and J Summerscales
In-Mould Gel-Coating for resin infusion processes using a flow medium
FPCM-10, Ascona - Switzerland, 11-15 July 2010.

B Muralidharan and J Summerscales
Resin Infusion Under Flexible Moulding technique by In-Mould Gel Coating using a flow medium
Indian Journal of Applied Research, 2013, 3(7), 292 - 293.

Project publications

J Summerscales
In-mould gel-coating for RTM and RIFT
FPCM-11, Auckland - New Zealand, July 2012.

AR Harper
Production of composite mouldings
Patent WO2013/132211A1, 12 September 2013.

W Rogers, C Hoppins, Z Gombos and J Summerscales
In-mould gel-coating of polymer composites – a review
Journal of Cleaner Production, 1 May 2014, 70, 282-291.

Zoltán Gombos and John Summerscales
Gel-coating for marine structures
1st PRIMaRE conference, Plymouth, 04-05 June 2014, poster.

Zoltán Gombos and John Summerscales
In-mould gel-coating with a separator layer
FPCM-12, Enschede - Netherlands, July 2014.

A Harper, Z Gombos and J Summerscales
In-mould surfacing with a silicone membrane
FPCM-12, Enschede - Netherlands, July 2014.

C Di Tomasso, ZJ Gombos and J Summerscales
Styrene emissions during gel-coating of composites
Journal of Cleaner Production, 15 November 2014, 83, 317–328.

Z Gombos and J Summerscales
In-mould gel coating for polymer composites
Composites Part A: Applied Science and Manufacturing, December 2016, 91(1), 203-210.