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Solutions for Defects in UV Wood Coatings (9)

Release time:

2026-03-21 06:52

Solutions for Defects in UV Wood Coatings (9)

In the wood coatings industry, UV wood coatings have become the preferred choice for many manufacturers due to their rapid curing, environmental friendliness, and high efficiency. However, in practical applications, these coatings often encounter several undesirable issues, particularly poor curing that leads to brittle film formation, which severely compromises both the aesthetic appeal and functional performance of the finished products. This article provides a detailed discussion of solutions to the problem of brittle UV wood coating films, helping manufacturers effectively address this challenge.

I. Precise Regulation of Solidified Energy

Excessive UV energy is the primary cause of brittle paint films. When the energy exceeds the critical threshold specified in the coating formulation, the crosslink density becomes excessively high, resulting in an over-dense three-dimensional network that severely restricts chain segment mobility. Consequently, the film loses its ability to absorb and dissipate impact energy, becoming rigid and fragile. It is recommended to precisely adjust the UV lamp power, irradiation distance, and conveyor speed based on the coating properties and film thickness, so as to keep the curing energy within an appropriate range. Regularly use an energy meter to monitor the output energy of the lamps and prevent over-curing caused by energy fluctuations. For highly reactive coatings, consider reducing the energy level or employing multiple low-energy exposures to strike a balance between crosslink density and flexibility.

II. Effective Control of Shrinkage Stress

UV curing is the rapid transformation of liquid monomers into a solid polymer, accompanied by volumetric shrinkage. When a single coat is applied too thickly, the resulting shrinkage cannot be compensated by flow within the coating film, leading to substantial tensile internal stresses. Even minor external forces can then trigger cracking. Therefore, the thickness of each individual coat should be carefully controlled in accordance with the coating’s properties. For applications requiring thick coatings, multiple thin coats are preferable to a single thick coat; each coat must be fully cured before the next is applied, allowing the shrinkage stresses to be relieved layer by layer.

When the shrinkage and flexibility of the primer and topcoat are mismatched, shear stresses develop at the interface, which can readily lead to brittle cracking of the topcoat. It is therefore essential to select a coating system with good compatibility to ensure that the shrinkage and elastic modulus of the primer and topcoat are well matched. In the design of the coating system, a combination of a flexible primer and a tough topcoat can be employed: the primer absorbs a portion of the stress, thereby reducing the load on the topcoat.

III. Scientific Design of Coating Formulations

At the formulation level, brittle paint films often result from an excessive proportion of rigid components and an insufficient proportion of flexible components, or from an overabundance of crosslinking agents that leads to overly dense crosslinking points. To address this, it is advisable to select resin systems with excellent flexibility, such as polyester acrylates or aliphatic polyurethane acrylates, which exhibit low shrinkage and superior flexibility. In formulation design, it is important to strike a proper balance between rigid and flexible monomers to avoid excessive crosslinking. For coatings requiring high hardness, toughness can be improved—without significantly compromising hardness—by incorporating toughening agents or elastomeric microspheres.

IV. Rational Matching of Coating Systems

In multi-layer coating systems, performance compatibility among the individual coats is critical. A significant mismatch in flexibility between the topcoat and the primer can lead to stress concentration at the interface, resulting in cracking. It is therefore recommended to select compatible, well-matched products with a reasonable performance gradient within the same coating system. For areas prone to cracking or for substrates with inherent brittleness, flexible additives can be incorporated into the primer to create a gradient structure in which flexibility decreases from the substrate outward, thereby effectively relieving internal stresses. During coating process design, sufficient consideration should be given to subsequent processing requirements, and an adequate margin of flexibility should be built in from the outset.

V. Conclusion

The issue of brittle paint films caused by inadequate curing of UV wood coatings is complex and challenging, requiring a comprehensive solution that addresses multiple factors. By precisely controlling UV energy, optimizing the coating application process, adjusting the coating formulation, and adopting advanced equipment and technologies, the curing quality and film performance of UV wood coatings can be significantly improved. These solutions not only help resolve current challenges but also provide strong support for the sustainable development of the wood coating industry.

Disclaimer: The above content is sourced from the internet and is provided for reference only. If any infringement occurs, please contact us, and we will remove it promptly.

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, contains 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.
Sanding 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-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-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.
Apply primer
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-02	Phosphate ester acrylate	Enhances adhesion to substrates such as metal, glass, and plastic.
B-05	Phosphate ester acrylate	Enhances adhesion to substrates such as metal, glass, and plastic.
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, contains 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-effectiveness.
B-535	Polyester acrylate	Excellent adhesion, rapid curing, good 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, contains 20% TPGDA
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and excellent 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-effectiveness.
B-529	Polyester acrylate	Good adhesion, low shrinkage, and excellent resin compatibility.
B-560	Polyester acrylate	Fast curing and excellent pigment wetting
Gloss topcoat
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-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 photosensitizing promoter	Low color number, antioxidant and anti-polymerization, and 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, excellent wettability; suitable for LED UV.
B-601	Aromatic Polyurethane Acrylate	High hardness, scratch resistance, chemical resistance, and excellent cost performance.
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, and chemical resistance.
B-868	Organosilicon UV-Curable Resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon UV-Curable Resin	Excellent 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 wear resistance.
Matte topcoat
Product Model/English Abbreviation	Product Name/Product Type	Product Features
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-21C	Active amine photosensitizing promoter	Low color number, antioxidant and anti-polymerization, and enhanced curing rate
B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, excellent wettability, and a pleasant hand feel.
B-328R	Aliphatic polyurethane acrylate	Low gloss, excellent matting, good wetting, and a fine, smooth, and silky hand feel.
B-333	Aliphatic polyurethane acrylate	Low viscosity, excellent matting effect, good wetting properties, and excellent flexibility.
B-572	Polyester acrylate	Low viscosity, low odor, excellent wettability; suitable for LED UV.
B-650A	Aliphatic polyurethane acrylate	Low viscosity, excellent matting effect, fast curing, and good wettability.
B-868	Organosilicon UV-Curable Resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon UV-Curable Resin	Excellent 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 wear resistance.
Bright White Finish
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-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and excellent 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, excellent wettability; suitable for LED UV.
B-601	Aromatic Polyurethane Acrylate	High hardness, scratch resistance, chemical resistance, and excellent cost performance.
B-868	Organosilicon UV-Curable Resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon UV-Curable Resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
B-912	Aliphatic polyurethane acrylate	Fast curing, high hardness, good toughness, and excellent chemical and wear resistance.
Adherent
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-05	Phosphate ester acrylate	Enhances 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	Good adhesion, impact resistance, excellent flexibility, and yellowing resistance.
B-535	Polyester acrylate	Excellent adhesion, rapid curing, good flexibility, and yellowing resistance.
B-546	Polyester acrylate	Good adhesion, fast curing, and excellent 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, contains 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	Good adhesion, low shrinkage, and excellent resin compatibility.
Color correction
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-560	Polyester acrylate	Fast curing and excellent pigment wetting
Harden
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-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, 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, good toughness, and excellent chemical and wear resistance.
Matte
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, excellent wettability, and a pleasant hand feel.
B-328R	Aliphatic polyurethane acrylate	Low gloss, excellent matting, good wetting, and a fine, smooth, and silky hand feel.
B-329D	Aliphatic polyurethane acrylate	Low irritation, low viscosity, excellent wettability, and a pleasant feel.
B-333	Aliphatic polyurethane acrylate	Low viscosity, excellent matting effect, good wetting properties, and excellent 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 photopolymerization performance
B-530	Polyester acrylate	Low viscosity, excellent hydrophobicity, thixotropy, and improved ink misting
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 excellent adhesion.
B-431	Cycloaliphatic Specialty Acrylates	Yellowing resistance, excellent wettability, low viscosity, and fast curing
Dip coating
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-160D	Modified epoxy acrylate	Good flexibility, yellowing resistance, and excellent adhesion.
Roll 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 high fullness.
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, contains 20% TPGDA
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-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.
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 of black ink pigments.
B-520	Polyester acrylate	Low viscosity, high gloss, excellent wettability, and cost-effective
B-574C	Polyester acrylate	Low viscosity, low odor, excellent 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, contains 20% TPGDA
B-21C	Active amine photosensitizing promoter	Low color number, antioxidant and anti-polymerization, and enhanced curing rate
B-241	Aliphatic polyurethane acrylate	Fast curing, excellent skin feel, and yellowing resistance.
B-27	Active amine photosensitizing promoter	Low color number, 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 compliant with cigarette pack standards.
B-574C	Polyester acrylate	Low viscosity, low odor, excellent wettability; suitable for LED UV.
Excimer lamp
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-241	Aliphatic polyurethane acrylate	Fast curing, 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, contains 20% TPGDA
B-165	Modified epoxy acrylate	Good flexibility and strong adhesion
B-241	Aliphatic polyurethane acrylate	Fast curing, excellent skin feel, and yellowing resistance.
B-328M	Aliphatic polyurethane acrylate	Low gloss, low viscosity, excellent wettability, and a pleasant hand feel.
B-328R	Aliphatic polyurethane acrylate	Low gloss, excellent matting, good wetting, and a fine, smooth, and silky hand feel.
B-574C	Polyester acrylate	Low viscosity, low odor, excellent wettability; suitable for LED UV.
B-868	Organosilicon UV-Curable Resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
B-868H	Organosilicon UV-Curable Resin	Excellent leveling, smooth finish, fast curing, and stain resistance.
Single-item 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	Good 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	Tripropylene Glycol 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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Solutions for Defects in UV Wood Coatings (Part 10)

Solutions for Defects in UV Wood Coatings (Part 8)