Sipiol WL 1120-23 Smooth Automotive Weatherstrip Coating

Seal applications and surface function

Sipiol WL 1120-23 is a water-based, single-component automotive weatherstrip coating for EPDM and sponge rubber primary seals, trunk lid seals and hood seals. It is also used on O-rings.

Its smooth coating combines low friction, chemical resistance and elasticity, with abrasion resistance in rotating textile tests. It also helps reduce noise where the seal contacts coated metal surfaces.

Surface preparation and coating preparation

Remove surface contamination, then apply Sipiol WP 8556 or Cuvertin X 8536 primer. For low-polarity substrates, alternative surface preparation such as plasma treatment is recommended to improve adhesion. Select the preparation method for the actual substrate.

Stir the coating thoroughly at low speed and filter through a 125–200 μm sieve. If a lower viscosity is required, dilute with no more than 20% deionized water, by weight. Sipiol TH 2 additive can be used to increase viscosity. Confirm the actual addition levels for the intended application. Keep the spray container agitated to prevent settling.

Application and curing

Apply by brush or HVLP spray at temperatures above 10°C, with substrate temperature no higher than 120°C. The recommended dry-film thickness for optimum performance is 10–20 μm.

Cure at 130–200°C, with dwell time selected according to line speed and oven length. A typical condition is 1–2 minutes at a surface temperature of 180°C. Equipment can be cleaned with water.

Typical properties

Property	Typical value
Appearance	Black liquid
Viscosity at 25°C	10–150 mPa·s, Brookfield LVT, spindle 1, 30 rpm
Solids by weight	31–36%; 2.5 g sample dried for 30 minutes at 130°C

Typical values are for reference, not product specifications.

Supply and technical enquiries

Hongtu Chemical supplies Sipiol WL 1120-23 as an authorized distributor. Contact our team for quotations, technical documents or support with an in-line coating application.