Synthesis And Research Of Urethane Acrylates With Low Molecular Weight

Urethane acrylates (UA) are commonly used uv-cured resin and it can be divided into variety of species and possess different performances. Because of high double bond density, UA with low molecular weight can form more dense crosslinking network, the cured film possess high hardness, modulus, good solvent resistance and good adhesion for PET which is a widely used optical film. However, the cured film is brittle and fragile because of high double bond density. In this paper, we prepared a series of new-type UA with low molecular weight, the new-type UA possesses the properties as following:better flexibility, higher stiffness and modulus, better solvent resistance and adhesion for PET.In this paper, we selected ethylene glycol, butyl glycol,1,6-hexylene glycol, neopentyl glycol,1,4-cyclohexanol diol, hydroquinone and trimethylolpropane reacted with isophorone diisocyanate and hydroxyethyl acrylate/pentaerythritol triacrylate respectively, finally we synthesized 15 kinds of UA with low molecular weight. The synthesized materials were tested by Fourier transform infrared spectroscopy (FTIR), dynamic stability control (DSC), nuclear magnetic resonance ('H NMR), thermogravimetric analysis (TGA), thermal mechanical analysis (DMA), elongation at break, volume shrinkage and the cured films were tested by pendulum hardness, contact angle, gloss, adhesion, flexibility, solvent resistance.According to our research results, in contrast to UA with low molecular weight containing no glycol structure, containing glycol structure had better properties:more flexible, higher stiffness and modulus, higher volume shrinkage rate and double bond conversion rate, better solvent resistance and higher gloss. The test results showed:materials achieved our idea that the performance of materials was hard and tough. All samples possessed good adherence with PET films and ABS substance.In this paper, we also explored the influence of chain length, chain genre, saturation of hexatomic ring and functionality of unsaturated bond, the results showed:the UA that synthesized using hydroxyl ethyl acrylate, longer molecular chain could result to the following results:volume shrinkage, glass-transition temperature (Tg), modulus and stiffness decreased, the double bond conversion, contact angle and the elongation at break increased. When materials were linear structure, structure with lateral or loop structure, volume shrinkage rate and double bond conversion rate will decrease, Tg, modulus and stiffness will increase. When saturation of hexatomic ring increased, double bond conversion rate, volume shrinkage rate, flexibility, contact angle and elongation at break will increase, Tg, modulus, hardness and thermal stability will decrease. When functionality of unsaturated bond increases, double bond conversion rate, volume shrinkage rate, elongation at break, Tg, modulus and contact angle will increase. The UA that synthesized using pentaerythritol triacrylate, expect for the effect of functionality on modulus, hardness and Tg, other properties had the same regulation as above texts, In general, in contrast to the series of pentaerythritol triacrylate, the series of hydroxyethyl acrylate possessed higher double bond conversion rate, better flexibility and elongation at break, lower volume shrinkage rate, lower hardness, modulus and Tg.