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Types of UV Resins with Poor Adhesion to Substrates (Part 3)

Release time:

2026-09-29 23:16

Types of UV Resins with Poor Adhesion to Substrates (Part 3)

The chemical composition of UV‑curable resins for difficult‑to‑adhere substrates determines their adhesion mechanisms and performance characteristics. Resins with distinct chemistries exhibit unique features in molecular structure, functional group types, and interfacial behavior. Chlorinated polyolefin resins achieve physical anchoring through a molecular architecture similar to that of the substrate; organosilicon‑modified resins enhance wetting via low surface tension; fluorine‑containing modifiers optimize interfacial properties through surface enrichment; phosphate‑ester modifications strengthen adhesion through chemical bonding; and isobornyl ester modifications improve overall performance by leveraging steric hindrance. Understanding resin types from a compositional perspective helps guide the selection of key materials in formulation design.

I. Chlorinated Polyolefins

Chlorinated polyolefins represent a well‑established approach to addressing adhesion challenges in polyolefin substrates. Chlorinated polypropylene, with a molecular structure similar to that of polypropylene, can form strong interfacial bonding with the substrate in accordance with the principle of “like dissolves like.” Moreover, chlorinated polyolefins can penetrate the substrate surface, creating physical entanglements and forming surface crystallization, thereby enhancing peel strength.

By grafting polar functional groups such as maleic anhydride onto chlorinated polypropylene, its compatibility and reactivity with UV‑curable resins can be further enhanced. The chlorine content in modified chlorinated olefins must be precisely controlled; an optimal chlorine level promotes improved resin–resin compatibility and adhesion. In formulation design, chlorinated polypropylene resins are often blended with methyl methacrylate resins to serve as a bridge between non‑polar substrates and the coating film. These resins exhibit high‑grade adhesion to polypropylene substrates, along with excellent impact resistance and flexural durability, and are typically employed as primers or adhesion promoters.

II. Silicone-Modified Types

Silicone‑modified systems leverage the low surface tension of polysiloxanes to enhance wetting and adhesion. Acrylic‑modified polydimethylsiloxane combines the low surface tension of silicones with the photocurable reactivity of acrylates, enabling wetting and adhesion on extremely low‑surface‑energy substrates such as polyethylene, polypropylene, and polyesters.

These resins typically contain polymerizable acrylate functional groups, enabling them to participate in curing reactions and become part of the polymer network. Researchers have synthesized a bifunctional end‑capping agent bearing two acryloyloxy groups and reacted it with polydimethylsiloxane to prepare high‑molecular‑weight acrylic‑modified organosilicon polymers, which enhance storage stability while maintaining adhesion. Organosilicon‑modified resins offer low surface tension and excellent wettability, making them suitable for a wide range of low‑surface‑energy substrates. However, the incorporation of siloxane segments may compromise the coating’s mechanical properties and optical transparency, necessitating a careful balance between adhesion and other performance attributes in the formulation.

III. Fluorine-Containing Modified Types

Fluorine‑containing modifiers reduce surface tension and enhance chemical stability by incorporating fluorinated moieties. Fluorinated polyurethane acrylate oligomers can lower the surface tension of coatings, enabling them to spread effectively on low‑surface‑energy substrates. Fluorinated acrylate monomers are also frequently employed to tune the surface energy of the system.

During film formation, these resins selectively enrich fluorinated segments at the coating surface, reducing surface energy while preserving bulk properties. Comb‑like fluorinated epoxy acrylate oligomers achieve this by covalently attaching fluorinated side chains to a UV‑curable backbone; during film formation, the fluorinated segments concentrate at the air–coating interface, with the wetting behavior governed by a thin fluorinated surface layer. Photocurable modifications of fluorinated resins are also advancing: by introducing alternating fluorinated vinyl and vinylic ether units into the molecular backbone, it is possible to simultaneously attain weatherability, chemical stability, and corrosion resistance. The key advantage of fluorine‑modified resins lies in their ability to deliver outstanding surface performance with relatively low fluorine content.

IV. Phosphate Ester-Modified Type

Phosphate‑ester‑modified systems enhance adhesion through the interaction between phosphate ester groups and the substrate surface. Phosphate ester groups exhibit a specific affinity for metallic and glass substrates, enabling strong interactions with surface hydroxyl groups.

Acrylate‑functionalized phosphate esters can be incorporated into the cured network via copolymerization, thereby mitigating additive migration and exudation. These raw materials exhibit light color, low acid value, and excellent adhesion, and their multiple functional groups enhance resin adhesion to a wide range of substrates, including metals, glass, and plastics. Silane‑modified acrylate phosphate esters represent a novel class of composite adhesion promoters developed in recent years; by integrating silane coupling agents, acrylates, and phosphate compounds, they simultaneously facilitate both chemical bonding and mechanical interlocking. The acid value of phosphate‑based raw materials must be carefully controlled, as a high acid value can accelerate the decomposition of alkaline photoinitiators, thereby shortening the formulation’s shelf life.

V. Isoborneol Ester–Modified Type

Isobornyl ester‑modified polymers enhance overall performance by incorporating isobornyl ester moieties. These moieties feature a bulky, rigid structure, low polarity, and a pronounced steric hindrance effect. Copolymers containing isobornyl ester groups exhibit excellent adhesion to polypropylene.

Its bulky side groups hinder the back‑addition of monomers to the chain‑end radical during polymerization, significantly reducing both short‑chain and long‑chain branching; the resulting structural regularity enhances the stability of interfacial adhesion. Studies have shown that resins containing isobornyl esters exhibit excellent thermal stability, high hardness, outstanding solvent resistance, and low curing shrinkage. Isobornyl acrylate is a commonly used reactive diluent monomer, and its low‑shrinkage characteristics help minimize interfacial stresses during curing. Resins modified with isobornyl esters are well suited for applications demanding high hardness and superior solvent resistance.

VI. Conclusion

Based on their chemical composition, UV‑curable resins for difficult‑to‑adhere substrates can be classified into chlorinated polyolefin‑based, organosilicon‑modified, fluorine‑modified, phosphate‑ester‑modified, and isobornyl ester‑modified types. Chlorinated polyolefins address adhesion challenges to polyolefins through “like dissolves like” interactions and physical entanglement; organosilicon‑modified systems leverage low surface tension to enhance wetting; fluorine‑modified formulations optimize interfacial properties via surface‑enrichment effects; phosphate‑ester‑modified resins rely on chemical bonding to improve adhesion; and isobornyl ester‑modified resins boost overall performance through steric hindrance. These approaches are not mutually exclusive; in practice, ideal adhesion is often achieved by blending and synergizing different types. When selecting a formulation, it is essential to match the chemical composition to the substrate type, application conditions, and desired performance characteristics.

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.

Bossin Related Product Recommendations – Membrane Materials
Difficult to adhere to the substrate
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-186	Modified epoxy acrylate	Boil-resistant, excellent adhesion, high-temperature resistant, chemically resistant
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-546	Polyester acrylate	Good adhesion, fast curing, and excellent flexibility.
B-590	Polyester acrylate	Good adhesion, fast curing, and excellent pigment wetting.
BM2224 (EO-HDDA)	Ethoxylation of 1,6-hexanediol diacrylate	It exhibits excellent adhesion to plastics, good dilutability, and low volatility.

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Types of UV Resins with Poor Adhesion to Substrates (Part II)