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Which substrates are suitable for UV vacuum plating?

Release time:

2026-05-28 17:19

Which substrates are suitable for UV vacuum plating?

The UV vacuum plating process can impart a metallic finish to non-metallic substrates such as plastics, offering broad substrate compatibility. Different types of substrates have varying requirements for coating adhesion, heat resistance, and processability, making them suitable for distinct product applications. Understanding the characteristics of each substrate type and its compatibility with vacuum plating is essential for selecting appropriate materials and ensuring high‑quality coatings.

I. Substrates Prone to Adhesion

ABS plastic is one of the most widely used substrates in vacuum electroplating. It exhibits excellent adhesion to UV‑curable coatings, boasts superior processability, and delivers a high‑gloss finish, enabling the formation of uniform, strongly adherent platings. ABS is suitable for most UV‑based vacuum plating processes; however, its heat resistance is relatively limited, typically not exceeding 80°C. This material is extensively employed in applications such as cosmetic packaging, automotive interior components, and electronic device housings.

PC plastic (polycarbonate) exhibits excellent heat resistance and can withstand high temperatures. By applying a vacuum electroplating process followed by a UV‑cured topcoat, PC material can meet the high‑temperature requirements of automotive components. According to available data, the UV primer used for PC lamp reflectors must demonstrate thermal stability of at least 120°C. Additionally, PC offers superior transparency and impact strength, making it well suited for applications such as lamp reflectors, optical components, and electronic products that demand robust heat resistance.

ABS+PC alloy combines the processability of ABS with the heat resistance of PC, making it widely used in vacuum electroplating. This material offers high strength and excellent heat resistance while maintaining good processability and a smooth surface finish, and is extensively employed in automotive interior components and electronic device housings. In coating formulations, dedicated primers have been developed specifically for this type of substrate, providing strong adhesion to aluminum, tin, indium, and other plated surfaces.

II. Substrates with Poor Adhesion

PP plastic (polypropylene) is a low‑surface‑energy material with poor adhesion to UV coatings, requiring special surface treatment to achieve satisfactory plating results. Currently, dedicated vacuum‑plating primers for PP are available, delivering excellent adhesion without the need for flame treatment; these are primarily used in applications such as cosmetic packaging. PP also exhibits excellent chemical stability and corrosion resistance, making it widely employed in cosmetic packaging.

PETG is another substrate that is difficult to bond to. Similar to PP, PETG also requires a specialized primer formulation to achieve strong adhesion. The UV vacuum‑plating primer designed for this type of material offers excellent leveling and adhesion, with outstanding adhesion to aluminum coatings, and is primarily used in applications such as cosmetic packaging.

PA (nylon) is also a substrate with poor adhesion and typically requires pre‑coating with a primer or surface activation treatment to ensure the adhesion of vacuum‑deposited coatings.

PE (polyethylene) is a low‑surface‑energy material with poor adhesion to UV coatings, necessitating corona or plasma treatment to enhance surface wettability and the use of a specialized primer formulation.

III. Engineering Plastics and Special Substrates

BMC (Bulk Molding Compound) is a thermosetting plastic that demands high heat resistance. The UV‑curing primer used as a base coat for BMC must exhibit heat resistance of 180°C or higher. BMC materials are primarily employed in applications such as automotive headlamp reflectors, where they are subjected to elevated temperatures. When formulating a UV‑curable primer for BMC headlamp reflectors, it is essential to increase the crosslink density of the coating to ensure excellent sealing performance.

Glass-fiber-reinforced engineering plastics such as PC are also used in vacuum plating. These materials may exhibit exposed glass fibers on their surfaces, necessitating the application of a primer with excellent filling properties to seal surface defects. For glass-fiber–reinforced PC substrates, it is typically advisable to apply a pretreatment agent beforehand to enhance adhesion.

IV. Comparison of Substrate Compatibility

Easily adherent substrates (ABS, PC, and ABS/PC) exhibit excellent adhesion to UV coatings, enabling superior plating results without the need for special pretreatment. They are suitable for a wide range of applications and benefit from a highly mature processing technology.

Poor adhesion to challenging substrates (such as PP, PETG, PE, and PA) requires specialized primer formulations or surface activation treatments. While targeted product solutions are currently available, they demand stringent process control.

High-temperature‑resistant substrates (PC, BMC) impose specific requirements on the heat resistance of UV‑cured primers: PC requires a minimum of 120°C, while BMC demands at least 180°C, making them suitable for high‑temperature applications such as automotive headlight reflectors.

V. Factors Influencing Substrate Selection

When selecting a substrate, the following factors must be considered: adhesion is the primary concern; different substrates exhibit widely varying adhesion to UV‑curable coatings, directly determining the reliability of the coating quality. Heat resistance is a critical performance indicator in automotive components and other applications, and both the substrate and the coating must meet the thermal‑stability requirements of the intended service environment. Surface flatness affects the mirror‑like finish of the coating; for substrates with high surface roughness, primer application is necessary to fill in defects. Volatile substances present in the substrate can outgas under vacuum conditions, compromising coating quality, and thus require sealing via a primer.

VI. Conclusion

The substrates suitable for UV vacuum plating primarily include easily adherent plastics such as ABS, PC, and ABS/PC, as well as difficult-to-adhere plastics like PP and PETG that require special primer treatments, along with engineering plastics such as BMC and glass-fiber‑reinforced PC. Easily adherent substrates exhibit excellent adhesion to UV coatings, benefit from mature processes, and enjoy broad applications; difficult-to-adhere substrates necessitate tailored primer formulations or surface‑treatment methods, though proven solutions are already available; and high‑temperature‑resistant substrates are ideal for specialized applications such as automotive headlamp reflectors. Understanding the characteristics of each substrate type and its compatibility with vacuum plating processes helps inform sound decisions during product design and material selection, thereby ensuring coating quality and production efficiency.

Disclaimer: The above content has been compiled from publicly available sources and is provided for reference only. If any infringement occurs, please contact us, and we will address it promptly.

Bosheng’s Recommended Products – Vacuum Plating
Primer
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, contains 20% TPGDA.
B-151	Modified epoxy acrylate	Low halogen, yellowing-resistant, excellent plating performance, and strong adhesion.
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and excellent adhesion.
B-163	Modified epoxy acrylate	Good flexibility, excellent pigment wetting, and strong adhesion.
B-165	Modified epoxy acrylate	Good flexibility and strong adhesion
B-212A	Aromatic polyurethane acrylate	High cost-performance, excellent plating adhesion, good toughness, and resistant to boiling water.
B-221	Aliphatic polyurethane acrylate	Fast curing, resistant to boiling water
B-268M	Aliphatic polyurethane acrylate	Good flexibility, excellent adhesion, superior plating performance, and strong hiding power.
B-574C	Polyester acrylate	Low viscosity, low odor, excellent wettability, suitable for LED UV.
B-619W	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, wear resistance, and chemical resistance.
Intermediate coat
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-374	Aliphatic polyurethane acrylate	Good flexibility, excellent leveling, resistant to abrasion and chemicals, and resistant to yellowing.
B-601	Aromatic polyurethane acrylate	High hardness, scratch resistance, chemical resistance, and excellent cost-effectiveness.
B-6020	Special functional group acrylate	Resistant to boiling water, excellent color development, and strong interlayer adhesion.
Topcoat
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-221	Aliphatic polyurethane acrylate	Fast curing, resistant to boiling water
B-301	Aromatic polyurethane acrylate	Fast curing, excellent toughness, and good sandability.
B-302	Aromatic polyurethane acrylate	Fast curing, high strength, excellent toughness, and good grindability.
B-368	Aliphatic polyurethane acrylate	Good toughness, excellent leveling, excellent bend resistance, and excellent heat resistance.
B-374	Aliphatic polyurethane acrylate	Good flexibility, excellent leveling, resistant to abrasion and chemicals, and resistant to yellowing.
B-574C	Polyester acrylate	Low viscosity, low odor, excellent wettability, suitable for LED UV.
B-601	Aromatic polyurethane acrylate	High hardness, scratch resistance, chemical resistance, and excellent cost-effectiveness.
B-6016C	Special functional group acrylate	Easy to apply, resistant to yellowing and boiling water, and improves the appearance of the paint film.
B-6019	Special functional group acrylate	Good leveling, excellent wetting, resistant to boiling water, and superior color dispersion.
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, and chemical resistance.
B-615A	Aliphatic polyurethane acrylate	Fast curing, excellent toughness, wear resistance, and chemical resistance.
B-619W	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, wear resistance, and chemical resistance.
B-6210	Aliphatic polyurethane acrylate	Low viscosity, chemical resistance, environmental resistance, and dual photothermal curing.
B-6211	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch-resistant, and free of organotin.
B-919B	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, and outstanding chemical and wear resistance.
Monomer Recommendation
Product Model/English Abbreviation	Product Name/Product Type	Product Features
BM2223 (TPGDA)	Di(propylene glycol) diacrylate	Good flexibility and low volatility
BM3231 (TMPTA)	Trimethylolpropane triacrylate	High crosslink density, high hardness, high gloss, and excellent wear resistance.
BM3235 (PET3A)	Pentaerythritol triacrylate	Fast curing, high crosslink density, high hardness, and chemical resistance.
BM3380 (3EO-TMPTA)	Pentaerythritol triacrylate	More flexible and less irritating than TMPTA.
BM6261 (DPHA-80)	Dipentaerythritol hexaacrylate	High crosslink density, high hardness, chemical and wear resistance, and water resistance.
BM6263 (DPHA-90)	Dipentaerythritol hexaacrylate	High crosslink density, high hardness, chemical and wear resistance, and water resistance.

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