Protective sheet and the applications thereof

Abstract

A protective sheet 10 is provided which exhibits excellent properties as a protective sheet and a satisfactory handleability. The protective sheet 10 is formed of a substrate 1 which is a plastic film and a pressure-sensitive adhesive layer 2 which is provided on one side of the substrate, and satisfies all of the following properties: (A) the total flexural rigidity DTrt at 25 DEG C. in a first direction and a second direction is from 3.010-6 to 2010-6 Pam3; (B) the total flexural rigidity DTht at 80 DEG C. is from 0.1010-6 to 1.210-6 Pam3; (C) the flexural rigidity ratio DR, defined as DTrt / DTht, is from 3.0 to 80; and (D) the tensions T1rt and T2rt at 25 DEG C. when stretched 10% in the first direction and the second direction respectively are at least 5.0 N / 10 mm.

Description

[0001] refer to [0002] This application claims priority based on Japanese Patent Application No. 2010-013026 for which it applied on January 25, 2010, and the whole content of this application is taken in this specification as a reference. technical field [0003] The present invention relates to a protective sheet, in particular to a protective sheet for plating masking which protects a portion not to be plated from a plating solution during metal plating. Background technique [0004] As a method of plating the connection terminal part of the circuit board (printed circuit board, flexible printed circuit board (FPC), etc.), it is possible to use adhesive bonding (also called pressure-sensitive Bonding, hereinafter the same) sheet, the method of performing plating treatment in the state of protecting the part from the plating solution. The pressure-sensitive adhesive sheet (protective sheet for plating masking) used in this form typically has a structure in which a resin...

AI Technical Summary

Problems solved by technology

However, in general, if the thickness of the base material is reduced, the handling (operability) during the production and use of the protective sheet is likely to decrease.

For example, the viscosity of the protective sheet becomes smaller (weaker) or the protective sheet is more easily stretched with respect to tensile stress, thereby completing the protection when the protective sheet is placed on a predetermined position of the attached body and peeled off from the attached body. Workability tends to decrease when the protective sheet is used

Such a decrease in handleability may become a major cause of a decrease in the productivity of the protective sheet itself and the productivity of products using the protective sheet (for example, a circuit board manufactured through a plating masking process using the protective sheet).

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