DB77 Non-Yellowing Plasticizer for Construction and Automotive MS Sealants

# DB77 Non-Yellowing Plasticizer for Construction and Automotive MS Sealants > **What makes a sealant turn yellow over its service life?** Yellowing in a plasticized sealant usually comes from oxidation of the plasticizer or from the reaction of the additive package with light, heat and atmospheric pollutants. A plasticizer that is resistant to that chemistry keeps the appearance of the joint stable. DB77 serves construction and automotive sealant systems with good compatibility with common resins and a stable anti-yellowing direction over long service life, suitable for formulations with weatherability and appearance requirements. ## Yellowing is an appearance failure that points to a chemistry problem A sealant joint that was white when installed and beige a year later is not only a cosmetic issue. In most cases the colour change tracks the same oxidation process that also changes the mechanical properties of the sealant, and on an automotive part it can also signal a risk of fogging or staining of adjacent surfaces. | Source of colour change | Mechanism | Formulation response | | :--- | :--- | :--- | | Plasticizer oxidation | Light and heat break down the molecule and form coloured products | Use a plasticizer that resists oxidation | | Residual aromatic structure | Absorbs ultraviolet energy and leads to conjugated colour bodies | Prefer a non-aromatic ester structure | | Additive interaction | Stabilizer or biocide reacting with the plasticizer | Re-check the whole additive package | | Surface contamination | Atmospheric pollutants and dirt retention | Consider surface energy and cleaning | | Heat history in production | Over-processing in the mixer | Control the temperature profile | DB77 is designed around the first two lines in that table. Its compatibility with common resins keeps it in the compound rather than at the surface, and the anti-yellowing direction is aimed at retaining appearance across a long service life. ## Compatibility with the resins used in MS sealant systems MS sealant systems are built on silyl-modified polymer chemistry, and the plasticizer has to remain compatible with the polymer, with calcium carbonate fillers and with the adhesion promoters that make the sealant bond to concrete, metal or painted panels. Incompatibility shows up in three ways: exudation of the plasticizer to the surface, loss of adhesion at the joint edge, and a drop in elongation after ageing. | Compatibility question | What to verify | Practical consequence | | :--- | :--- | :--- | | With the base polymer | Homogeneous blend, no surface film | Appearance stability and elongation retention | | With calcium carbonate fillers | No thickening or phase separation | Storage stability and extrusion behaviour | | With adhesion promoters | No loss of bond strength | Joint durability on the intended substrates | | With stabilizers and pigments | No colour shift after heat ageing | Colour consistency of the finished joint | | Over time and weather | No bloom or chalking | Retained appearance over service life | ## Construction and automotive requirements The two markets overlap but they do not use the same language. A construction sealant is usually assessed on movement capability, adhesion to masonry and weatherability over many years of ultraviolet exposure and rain. An automotive sealant is assessed on bond durability to painted and coated surfaces, non-staining of the adjacent trim, and behaviour over the vehicle temperature range, with appearance specifications that in interior applications extend to fogging and odour. | Application | Key requirement | Why the plasticizer matters | | :--- | :--- | :--- | | Building facade joints | Weatherability and colour stability | Plasticizer oxidation drives visible yellowing | | Window and panel sealing | Adhesion over movement | Compatibility affects joint durability | | Automotive body and trim sealing | Non-staining and bond durability | Migration can mark paint and trim | | Interior automotive sealing | Low fogging and low odour direction | Volatile content and ageing behaviour | ## Testing appearance stability the right way Appearance claims cannot be proven by a short oven exposure alone. A meaningful evaluation of a non-yellowing direction combines accelerated weathering with a quantified colour measurement, and it compares the candidate against the current formulation under identical conditions. | Test approach | What it shows | Note | | :--- | :--- | :--- | | Accelerated weathering (ultraviolet and moisture cycling) | Speed of colour development | Use the same cycle for every sample | | Colour measurement (colour difference value) | Magnitude of change, not just a visual judgement | Report the numerical change | | Heat ageing | Sensitivity to production heat history | Relates to processing control | | Outdoor exposure | Real service behaviour | Long duration, useful as the final check | | Mechanical tests after ageing | Whether appearance and performance move together | Elongation and adhesion retention | ## Frequently asked questions **Does DB77 eliminate yellowing completely?** No plasticizer can guarantee that. DB77 is designed with a stable anti-yellowing direction over long service life, and the final result depends on the full formulation, the filler package and the exposure conditions. Appearance should be verified with weathering and colour measurement. **Is DB77 suitable for both construction and automotive sealants?** It is described as serving construction and automotive sealant systems, with good compatibility with common resins. Both markets should confirm the specific requirements of their own specification, particularly interior automotive fogging and odour limits. **Can it be used in other sealant chemistries?** Compatibility has to be confirmed for each system. For MS and related sealant systems where a plasticizer is part of the formulation, DB77 is the intended application. **Will it change the extrusion behaviour?** Compatibility with fillers is one of the factors that keeps viscosity stable, but the filler grade and loading also matter. A short trial comparing extrusion rate and surface finish is the practical check. **How do I start an evaluation?** We provide a 1kg complimentary testing sample and the current technical data. A trial comparison against your existing plasticizer, measured with colour difference after accelerated weathering, is the usual first step. ## Request a sample and a recommendation Tell us your sealant system and the appearance requirement and our team will supply DB77 as a 1kg complimentary testing sample dispatched worldwide via DHL or FedEx. Trial order MOQ is 1 MT, and bulk shipments are loaded as 23 MT flexitank containers from Ningbo or Shanghai.