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Functional UV Wood Coating

Release time:

2026-04-10 16:58

In UV wood coating systems, different types of coatings perform distinct functional roles, collectively forming a comprehensive coating solution. Adhesion, fill, and hardening are the three core performance requirements, each corresponding to specific layers and functional positions within the coating system. Understanding the technical characteristics, application scenarios, and compatibility of these coating types is crucial for the rational design of coating processes.

I. Adhesive UV Coating

The core function of adhesion-type UV coatings is to address the adhesion between the coating film and the substrate, serving as the foundational layer of the coating system.

1. Applicable Substrates

Adhesion-type UV coatings are primarily used on solid wood substrates, veneered panels, and substrates with poor adhesion. Solid wood surfaces such as oak and black walnut contain natural constituents like oils and tannins, which can hinder the direct adhesion of UV coatings. Adhesion-type UV coatings achieve strong bonding by employing a specially designed resin system that forms chemical bonds with the hydroxyl groups on the wood surface. Veneered panels often suffer from insufficient topcoat adhesion due to differences in material properties between the wood veneer and the substrate, as well as residual adhesive; in such cases, an adhesion-type UV coating can serve as a primer layer to enhance bond strength. Additionally, some engineered wood panels have dense, low-surface-energy surfaces that are difficult for conventional UV primers to wet; adhesion-type UV coatings address these challenges by optimizing the resin formulation and surface tension to ensure effective wetting and adhesion.

2. Scheme for Enhancing Interlayer Adhesion

Key measures to enhance interlayer adhesion include:

(1) Control the degree of primer curing: over-curing results in an excessively dense surface that hinders topcoat adhesion, while under-curing leads to insufficient coating strength.

(2) Optimize surface energy matching so that the primer both wets the substrate and is well wetted by the topcoat; select compatible products, as primers and topcoats from the same supplier are typically subjected to compatibility testing.

(3) Incorporate functional monomers to enhance chemical bonding with the substrate and topcoat.

II. Filler-Type UV Coatings

The primary function of fill-type UV coatings is to seal wood vessels and micropores, thereby providing a smooth, dense coating substrate.

1. Catheter Sealing and Primer Filling

Wood is a porous material, with significant variation in vessel diameter among different species. Ring-porous woods such as oak and ash have relatively large vessels, whereas diffuse-porous woods like birch and maple have fine vessels. The function of fill-type UV coatings is to fill these vessels and microvoids, thereby creating a uniform underlying layer. Such coatings typically contain inorganic fillers such as talc and calcium carbonate, which effectively seal the substrate’s vessels and minor defects; upon curing, they form a robust filling layer. The type and dosage of filler have a substantial impact on the filling performance: an appropriate amount of filler can enhance the coating’s hardness, adhesion, and impact resistance, whereas excessive filler can reduce gloss and weaken mechanical properties.

2. Open-System Coating vs. Closed-System Coating

Open-pore finishing exposes the wood’s natural pores, resulting in prominent grain, clear texture, a thin paint film, and a natural tactile feel; it is suitable for woods with deep vessels, where the primer need only provide basic sealing. Closed-pore finishing completely seals the wood’s surface pores, producing a full, thick paint film with a smooth, even surface; it is ideal for high-gloss finishes and products that demand exceptional surface flatness, requiring multiple coats of primer and sanding.

III. Hardened UV Coating

The core function of hard UV coating is to enhance the hardness and scratch resistance of the coated surface.

1. Principle of Surface Scratch Resistance

Hardening UV coatings achieve enhanced scratch resistance through high crosslinking density and the reinforcement provided by functional fillers. The hardening primer utilizes high-functionality resins and monomers; upon curing, these form a highly crosslinked polymer network, significantly increasing coating hardness and improving resistance to indentation and scratching. In addition, hard fillers such as glass powder and fumed silica are incorporated; these nanoscale particles are uniformly dispersed throughout the coating film, effectively distributing and dissipating external forces and thereby slowing the wear of the resin matrix.

2. Order of Pairing

In a complete UV coating system, the sequence in which the primer, fill coat, and hardening coat are applied is critical. The standard approach involves applying an adhesion primer, a filling primer, a hardening primer, and then a topcoat in that order. Taking laminate flooring as an example, a well-established coating formulation addresses adhesion with an adhesion primer, achieves surface smoothness with a sanding primer, enhances scratch resistance with a hardening wear-resistant primer, and delivers the desired visual effect with a spray-applied topcoat. For light-colored and clear coatings, it is essential to use a full suite of high yellowing-resistant UV coatings, with appropriate partial or full curing between layers to ensure intercoat adhesion and optimal final performance.

IV. Conclusion

Adhesive UV coatings, filling UV coatings, and hardening UV coatings each emphasize different aspects within the coating system, collectively forming a comprehensive performance framework. In practical applications, it is essential to select and combine these three types of products appropriately based on the substrate condition, product positioning, and desired performance outcomes, in order to achieve optimal coating quality and product performance.

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Boxing Recommended Products – UV Wood Coatings
Adherent
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-05	Phosphate ester acrylate	Enhance adhesion to substrates such as metal, glass, and plastic.
B-509B	Polyester acrylate	Good adhesion, good flexibility, and excellent pigment wetting
B-531	Polyester acrylate	Excellent adhesion, impact resistance, good flexibility, and yellowing resistance.
B-535	Polyester acrylate	Excellent adhesion, rapid curing, good flexibility, and yellowing resistance.
B-546	Polyester acrylate	Excellent adhesion, rapid curing, and good flexibility.
B-590	Polyester acrylate	Excellent adhesion, rapid curing, and good pigment wetting.
Filler type
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, containing 20% TPGDA.
B-520	Polyester acrylate	Low viscosity, high gloss, excellent wettability, and cost-effective
B-522	Polyester acrylate	Low shrinkage, excellent flexibility, strong adhesion, and high cost-effectiveness.
B-529	Polyester acrylate	Excellent adhesion, low shrinkage, and good resin compatibility.
Harden
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, containing 20% TPGDA.
B-301	Aromatic Polyurethane Acrylate	Fast curing, excellent toughness, and good grindability.
B-302	Aromatic Polyurethane Acrylate	Fast curing, high strength, good toughness, and excellent grindability.
B-560	Polyester acrylate	Fast curing and excellent pigment wetting
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 performance.
B-912	Aliphatic polyurethane acrylate	Fast curing, high hardness, excellent toughness, and outstanding chemical and wear resistance.
Individual Recommendation
Product Model/English Abbreviation	Product Name/Product Type	Product Features
BM2223/TPGDA	Di(propylene glycol) diacrylate	Good flexibility and low volatility
BM2224/EO-HDDA	Ethoxylated 1,6-hexanediol diacrylate	Excellent adhesion to plastics, good dilutability, 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 excellent chemical resistance.
BM3380/3EO-TMPTA	Ethoxylated trimethylolpropane 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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Diverse UV Wood Coating Finishes (Part 1)

Application Areas of UV Wood Coatings