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Common Defects in UV Wood Coatings (Part 1)

Release time:

2026-03-11 07:16

Common Defects in UV Wood Coatings (Part 1)

In the fields of modern furniture manufacturing and wood product coating, UV wood coatings have become the preferred coating solution for numerous enterprises, thanks to their outstanding characteristics such as rapid curing, high production efficiency, and superior environmental performance. However, in actual production applications, UV coating is not always smooth sailing. Due to improper process control, inadequate substrate preparation, or changes in the operating environment, various coating defects frequently occur, severely impacting both the aesthetic quality and service life of products. Among these, complete delamination—a typical form of adhesion failure—is particularly insidious and highly destructive; it often only becomes apparent after coating has been completed or even after the product has been delivered, imposing substantial rework costs and reputational damage on manufacturers. Thoroughly analyzing the characteristic features, affected areas, and underlying root causes of this phenomenon is not only crucial for improving coating quality but also forms the foundation for achieving process optimization and mitigating systemic risks.

I. Description of the Phenomenon

The paint film has completely lost its adhesion to the substrate, resulting in extensive delamination. With a gentle push or flick of the hand, the paint film can be moved in large sections. When tape is applied and then peeled off, the entire layer of paint comes away cleanly, with neat, smooth edges and no jagged or uneven tear marks. Delamination may occur between the primer and the wood surface, at which point the bare wood substrate becomes visible; alternatively, it may occur between the topcoat and the primer, revealing the smooth surface of the underlying primer. The detached paint film typically remains intact and retains a certain degree of flexibility, allowing it to be lifted from the substrate like a sheet of plastic wrap. When subjected to external impact or temperature fluctuations, the delaminated area will bulge and become hollow, and pressing down with a finger will produce a loose, spongy sensation.

II. In-depth Analysis of the Underlying Causes

1. Intrinsic Rejection at the Substrate Level

(1) Oils and Waxes: Certain solid wood or polished wood panels naturally retain traces of oils or waxy substances on their surfaces. These substances form an isolating layer that prevents UV coatings from penetrating the wood cells, thereby hindering the formation of effective mechanical adhesion and intermolecular forces.

(2) Dust Coverage: If the dust generated after sanding is not thoroughly removed through high‑pressure blowing or powerful vacuuming, the fine powder remaining in the wood’s vessel pores will form a physical barrier. After the paint film has cured, it actually sits atop the dust layer rather than bonding with the wood itself.

(3) Abnormal chemical composition of wood: Some woods are rich in tannic acid or have a pH that deviates from the normal range, which can react with the components in UV coatings and compromise the stability of the interfacial layer.

2. Physical anchor failure

(1) Excessively Smooth Sanding: If you use excessively fine sandpaper for final polishing, the wood surface will become overly smooth, reducing the capillary channels and microscopic irregularities necessary for paint to penetrate the wood cells, thereby significantly decreasing the physical interlocking force.

(2) The substrate is too loose: For particleboard or medium‑density fiberboard, if the surface filler layer is insufficient or the filler layer itself has poor adhesion to the substrate, failure will occur at the interface between the filler layer and the substrate when stress concentrates.

3. Absence of Chemical Crosslinking

(1) Overcuring of the primer: This is the most common cause of interlayer delamination. When the first coat of primer is exposed to excessive UV light, the photoinitiator within it is completely consumed, the resin cross‑linking density reaches its peak, and the surface becomes inert and highly dense. The subsequent topcoat cannot form chemical bonds with the primer and must rely solely on weak physical adhesion. As a result, when subjected to external forces or temperature fluctuations, the two layers easily separate.

(2) Excessive Interlayer Spacing: After sanding the primer, if the surface is left exposed to the workshop environment for an extended period, it will absorb moisture, organic volatile compounds, or even microscopic dust particles from the air, forming an extremely thin, weak interfacial layer. As a result, even when paint is applied again, a strong bond cannot be achieved.

III. Conclusion

Delamination across an entire coating layer is one of the most severe forms of adhesion failure in UV wood coatings. Its root causes are often not singular; rather, it arises from the combined effects of multiple variables, including substrate characteristics, surface preparation, coating curing, and environmental factors. From surface contamination caused by oils and waxes to the loss of physical anchorage due to overly fine sanding, and even chemical inertness triggered by over‑cured primers, any oversight at any stage can serve as the spark that ignites coating failure. This underscores the need, in pursuit of highly efficient UV coating production lines, to establish a comprehensive quality control mindset—treating every single process step as an indispensable link in the adhesion chain—in order to ensure that the coating film achieves a truly unbreakable bond with the substrate, thereby delivering high‑quality products that can withstand the test of time and external forces.

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Boxing Recommended Products – UV Wood Coatings
Putty primer
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 performance.
Sanding Primer
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-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and strong adhesion.
B-163	Modified epoxy acrylate	Good flexibility, excellent pigment wetting, and strong adhesion.
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 performance.
Primer
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-02	Phosphate ester acrylate	Enhance adhesion to substrates such as metal, glass, and plastic.
B-05	Phosphate ester acrylate	Enhance adhesion to substrates such as metal, glass, and plastic.
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, containing 20% TPGDA.
B-165	Modified epoxy acrylate	Good flexibility and strong adhesion.
B-522	Polyester acrylate	Low shrinkage, excellent flexibility, strong adhesion, and high cost performance.
B-535	Polyester acrylate	Good adhesion, fast curing, excellent flexibility, and yellowing resistance.
B-546	Polyester acrylate	Good adhesion, fast curing, and excellent flexibility.
White primer
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-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and strong adhesion.
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 performance.
B-529	Polyester acrylate	Good adhesion, low shrinkage, and excellent resin compatibility.
B-560	Polyester acrylate	Fast curing and excellent pigment wetting.
Glossy topcoat
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-163	Modified epoxy acrylate	Good flexibility, excellent pigment wetting, and strong adhesion.
B-165	Modified epoxy acrylate	Good flexibility and strong adhesion.
B-21C	Active amine photoinitiator	Low color, antioxidant and polymerization inhibitor, enhanced curing rate
B-301	Aromatic Polyurethane Acrylate	Fast curing, good toughness, and excellent grindability.
B-302	Aromatic Polyurethane Acrylate	Fast curing, high strength, good toughness, and excellent grindability.
B-574C	Polyester acrylate	Low viscosity, low odor, good wettability, suitable for LED UV.
B-601	Aromatic Polyurethane Acrylate	High hardness, scratch resistance, chemical resistance, and excellent value for money.
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, chemical resistance.
B-868	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
B-910A2	Aliphatic polyurethane acrylate	Low viscosity, yellowing resistance, chemical resistance, and steel wool resistance.
B-912	Aliphatic polyurethane acrylate	Fast curing, high hardness, good toughness, and excellent chemical and abrasion resistance.
Matte finish paint
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and strong adhesion.
B-163	Modified epoxy acrylate	Good flexibility, excellent pigment wetting, and strong adhesion.
B-21C	Active amine photoinitiator	Low color, antioxidant and polymerization inhibitor, enhanced curing rate
B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, good wettability, pleasant to the touch.
B-328R	Aliphatic polyurethane acrylate	Low gloss, excellent matting effect, good wetting properties, and a fine, smooth hand feel.
B-333	Aliphatic polyurethane acrylate	Low viscosity, good matting effect, excellent wettability, and good flexibility.
B-572	Polyester acrylate	Low viscosity, low odor, good wettability, suitable for LED UV.
B-650A	Aliphatic polyurethane acrylate	Low viscosity, excellent matting effect, fast curing, and good wettability.
B-868	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
B-910A2	Aliphatic polyurethane acrylate	Low viscosity, yellowing resistance, chemical resistance, and steel wool resistance.
B-912	Aliphatic polyurethane acrylate	Fast curing, high hardness, good toughness, and excellent chemical and abrasion resistance.
Bright white paint
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-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and strong adhesion.
B-301	Aromatic Polyurethane Acrylate	Fast curing, good toughness, and excellent 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, good wettability, suitable for LED UV.
B-601	Aromatic Polyurethane Acrylate	High hardness, scratch resistance, chemical resistance, and excellent value for money.
B-868	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
B-912	Aliphatic polyurethane acrylate	Fast curing, high hardness, good toughness, and excellent chemical and abrasion resistance.
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, excellent flexibility, and excellent pigment wetting.
B-531	Polyester acrylate	Good adhesion, impact resistance, excellent flexibility, and yellowing resistance.
B-535	Polyester acrylate	Good adhesion, fast curing, excellent flexibility, and yellowing resistance.
B-546	Polyester acrylate	Good adhesion, fast curing, and excellent flexibility.
B-590	Polyester acrylate	Good adhesion, fast curing, and excellent 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 performance.
B-529	Polyester acrylate	Good adhesion, low shrinkage, and excellent resin compatibility.
Retouch color
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-560	Polyester acrylate	Fast curing and excellent pigment wetting.
Hardened
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, good toughness, and excellent 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, good wettability, suitable for LED UV.
B-601	Aromatic Polyurethane Acrylate	High hardness, scratch resistance, chemical resistance, and excellent value for money.
B-912	Aliphatic polyurethane acrylate	Fast curing, high hardness, good toughness, and excellent chemical and abrasion resistance.
Matte
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, good wettability, pleasant to the touch.
B-328R	Aliphatic polyurethane acrylate	Low gloss, excellent matting effect, good wetting properties, and a fine, smooth hand feel.
B-329D	Aliphatic polyurethane acrylate	Low irritation, low viscosity, excellent wettability, and pleasant to the touch.
B-333	Aliphatic polyurethane acrylate	Low viscosity, good matting effect, excellent wettability, and good flexibility.
B-650A	Aliphatic polyurethane acrylate	Low viscosity, excellent matting effect, fast curing, and good wettability.
Solid-color paint
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-519	Self‑Curing Polyester Acrylate	Self‑initiated Photocuring Performance
B-530	Polyester acrylate	Low viscosity, excellent hydrophobicity, thixotropic properties, and improved ink mist.
B-560	Polyester acrylate	Fast curing and excellent pigment wetting.
Yellowing resistance
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and strong adhesion.
B-431	Alicyclic Specialty Acrylates	Yellowing resistance, excellent wettability, low viscosity, fast curing.
Coating by spraying
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and strong adhesion.
Roller Coating
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-100	Bisphenol A epoxy acrylate	High hardness, high gloss, excellent chemical resistance, and rich body.
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, containing 20% TPGDA.
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and strong 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-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 performance.
Solvent-free spraying
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-251	Aromatic Polyurethane Acrylate	Fast curing, excellent flexibility, and good wetting performance with black ink pigments.
B-520	Polyester acrylate	Low viscosity, high gloss, excellent wettability, and cost-effective.
B-574C	Polyester acrylate	Low viscosity, low odor, good wettability, suitable for LED UV.
LED-UV
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-21C	Active amine photoinitiator	Low color, antioxidant and polymerization inhibitor, enhanced curing rate
B-241	Aliphatic polyurethane acrylate	Fast matting speed, excellent skin feel, and yellowing resistance.
B-27	Active amine photoinitiator	Low color, benzene-free, low odor, antioxidant and anti‑polymerization.
B-570	Polyester acrylate	Low viscosity, benzene‑free, low odor, suitable for LED UV.
B-574	Polyester acrylate	Benzene-free, low odor, and VOC levels meet cigarette packaging standards.
B-574C	Polyester acrylate	Low viscosity, low odor, good wettability, suitable for LED UV.
Excimer lamp
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-241	Aliphatic polyurethane acrylate	Fast matting speed, excellent skin feel, and yellowing resistance.
Skin feel
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-165	Modified epoxy acrylate	Good flexibility and strong adhesion.
B-241	Aliphatic polyurethane acrylate	Fast matting speed, excellent skin feel, and yellowing resistance.
B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, good wettability, pleasant to the touch.
B-328R	Aliphatic polyurethane acrylate	Low gloss, excellent matting effect, good wetting properties, and a fine, smooth hand feel.
B-574C	Polyester acrylate	Low viscosity, low odor, good wettability, suitable for LED UV.
B-868	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon Photocurable Resin	Good leveling, smooth finish, fast curing, and stain resistance.
Monomer Recommendations
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	Good adhesion to plastics, excellent 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 abrasion resistance, and water resistance.
BM6263/DPHA-90	Dipentaerythritol hexaacrylate	High crosslink density, high hardness, chemical and abrasion resistance, and water resistance.

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Common Defects in UV Wood Coatings (Part 2)

Diverse Application Methods for UV Wood Coatings