Photocurable inkjet ink

Abstract

An object of the present invention is to provide a photocurable inkjet ink with low volatility, which is useful in the manufacture of microlenses or electronic components. The photocurable inkjet ink of the present invention contains a polyfunctional (meth)acrylate (A), has a non-volatility of 75% or more in Evaluation Method 1, and has a viscosity of 1 mPa·s to 70 mPa·s (25°C). Monofunctional (meth)acrylate (B) and photopolymerization initiator (C), and the viscosity at 25°C is 1mPa·s~100mPa·s; [Evaluation method 1] the monofunctional (meth)acrylate (B): The weight ratio of pentaerythritol tetra(tri)acrylate=25:45 was mixed, and the evaluation liquid was produced. (1) The weight of the glass substrate of 5 cm x 5 cm was measured. (2) The evaluation liquid was dripped on the glass substrate of (1), and it applied so that a coating weight might become the error of 25 mg±2 mg by spin coating. (3) The weight of the glass substrate coated with the evaluation liquid of (2) was measured. (4) The weight of (1) was subtracted from the weight of (3) to calculate the coating weight of the evaluation liquid. (5) The glass substrate coated with the evaluation liquid in (3) was heated on a 50° C. hot plate for 15 minutes. (6) Measure the weight of the heated glass substrate of (5), subtract the weight of (1), and calculate the remaining amount of the evaluation liquid. (7) Calculate the non-volatility according to the following formula. Non-volatility % = balance ÷ coating weight x 100.

Description

technical field [0001] The present invention relates to a photocurable inkjet ink that can be preferably used for manufacturing optical devices such as image display devices. More specifically, it relates to an ink for forming a microlens that can be used in an optical system for improving stereoscopic imaging of an image or improving the light utilization efficiency of a device. [0002] Moreover, this invention relates to the photocurable inkjet ink which can be used suitably for manufacturing electronic components, such as a semiconductor device and a flexible wiring board. More specifically, it relates to a patterned insulating material for forming a buffer layer for wafer-level packaging, a rewiring insulating material, a barrier material, an underfill material, or a cover film for a flexible wiring board. ink. Background technique [0003] Regarding the microlens, it has been studied as a light guide plate for image display devices using its fine concave-convex struc...

AI Technical Summary

Problems solved by technology

Among them, acrylates are generally excellent in photocurability, but on the other hand, they have a strong odor and are highly irritating to the film. Therefore, photocurable resins containing these monomers have the disadvantage of impairing their working environment.

In addition, acrylates with lower viscosity are highly volatile, making it difficult to form fine patterns.

[0010] Those who use alkylene oxide or ε-caprolactone to modify these acrylate monomers to reduce odor or skin irritation have been developed, but the modified acrylate has its hardening speed or the hardness of the hardened product decreases, ink The disadvantage of increased viscosity

[0011] Patent Document 5 discloses that a composition containing a reactive oligomer as a urethane poly(meth)acrylate is effective for reducing odor or skin irritation. ) acrylate is obtained by the reaction of polyol, polyisocyanate and hydroxyl-containing (meth)acrylate, but it is difficult to be used as an inkjet ink because the viscosity of the composition is several thousand or more

[0012] Patent Document 6 discloses that a composition with a surface tension of 25 mN / m to 35 mN / m is effective for the formation of micro-droplets using the inkjet method, but the volatility of monomers has not been fully discussed

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