Structural member for electronic devices

Patent metadata

Field	Value
Publication number	US-2016152016-A1
Application number	US-201514925048-A
Country	US
Kind code	A1
Filing date	Oct 28, 2015
Priority date	Nov 27, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

Provided is a structural member for electronic devices which uses a material that is flexible and has excellent restoration properties after extension and stress relaxation properties. The structural member for electronic devices has the following properties A and B: (Property A) In a case where predetermined deformation is applied, stress that applies the deformation is relaxed (reduced) with time: and (Property B) In a case where the stress that applies deformation is 0, the deformation rarely remains while a resin composition is recovered. That is, when stress is 0, residual strain substantially becomes 0 (specifically 3% or lower).

First claim

What is claimed is:

1 . A structure for electronics structural member for electronic devices comprising
a resin composition; and an electronic element of which a portion comes into close contact with the resin composition, wherein, in the resin composition, stress generated due to any deformation caused by given strain decreases with time, and the resin composition recovers a shape before the deformation when the stress becomes approximately 0.

2 . The structural member for electronic devices of claim 1 ,
wherein, in constituent components, a stress relaxation ratio R and a residual strain ratio α measured by an extension-restoration test described below satisfy the following expression:
20%≦ R≦ 95%, and

0%≦α≦3%

[Extension-Restoration Test]
A resin composition piece (thickness: 50 μm, sample shape: dumbbell specimen No. 6 (measurement portion width: 4 mm, parallel portion length: 25 mm)) is used, an extension process is performed and thereafter a restoration process is performed by a tensile and compression testing machine based on ISO 3384 under the following conditions, and a stress relaxation ratio R and a residual strain ratio α are calculated according to the following calculation method.

Extension Process Conditions:
in order to eliminate deflection generated when the test piece is attached to a clamp, deflection correction being carried out at a force of 0.05 N or lower,
Testing rate: 25 mm/min from 0% to 25% extension
Temperature condition: 23° C.
Extension and holding conditions: a holding time of 5 minutes at 25% extension

Restoration process Conditions:
Testing rate: 0.1 mm/min until a tensile force becomes 0±0.05 N
Temperature condition: 23° C.
Stress relaxation ratio calculation method: a tensile force at the time of the end of the extension process is measured and is referred to as an initial tensile force F A0 . Thereafter, a strain amount is held under the above-described extension and holding conditions and the tensile force is measured after 5 minutes. This is referred to as F A (t 5 ). The stress relaxation ratio R is calculated by the following expression formula.

R
=

F

A



O

-

F
A



(

t



5

)

F

A



O

×
100

[

Expression



formula



1

]

Residual strain ratio calculation method: the strain amount is measured at a point when the tensile force becomes 0±0.05 N in the restoration process, and this amount is referred to as residual strain ratio α.

3 . The structural member for electronic devices of claim 2 ,
wherein, in a case where the resin composition is elongated in a range of 15% to 20% in the extension-restoration test, slopes of changes in tensile force during restoration and during extension with respect to strain amount satisfy the following expression:
slope during restoration/slope during extension≦0.95.

4 . The structural member for electronic devices of claim 2 ,
wherein the resin composition satisfies the following conditions: a stress value measured during maximum extension (during 25% extension) in the extension-restoration test becomes the maximum stress value, and in a case where measurement is started simultaneously with the end of the extension process in a stress relaxation property test below, a tensile force F B0 immediately after the end of the extension process and a tensile force F B (t 30 ) when 30 minutes has elapsed after the end of the extension process satisfy the following expression:
0.1≦ F B ( t 30)/ F B0 ≦0.7

[Stress Relaxation Property Test]
A resin composition piece (thickness: 50 μm, sample shape: dumbbell specimen No. 6 (measurement portion width: 4 mm, parallel portion length: 25 mm)) is used, an extension process is performed by a tensile and compression testing machine based on ISO 3384 under the following conditions, and a tensile force at the time of the end of extension is measured and is referred to as an initial tensile force F B0 . Thereafter, a tensile force F B (t 30 ) after 30 minutes is measured.

Extension Process Conditions:
In order to remove deflection that occurs when the test piece is attached to a gripper, deflection correction is performed. The deflection correction is performed with a force of 0.05 N or lower.
Testing rate: 25 mm/min until 50% extension
Temperature condition: 23° C.
Extension and holding conditions: a holding time of 30 minutes at 50% extension

5 . The structural member for electronic devices of claim 2 ,
wherein the resin composition satisfies the conditions described in (Expression formulae 1) even when the test is repeatedly performed two or more times.

6 . The structural member for electronic devices of claim 1 ,
wherein the resin composition contains at least a thermosetting resin and a curing agent thereof.

7 . The structural member for electronic devices of claim 6 ,
wherein the thermosetting resin is an epoxy resin.

8 . The structural member for electronic devices of claim 1 ,
wherein the resin composition has a film form.

9 . The structural member for electronic devices of claim 1 , further comprising:
a first conductive portion which connects the electronic element to the resin composition.

10 . The structural member for electronic devices of claim 1 , further comprising:
a second conductive portion which is electrically connected to the structural member from outside.

11 . The structural mem

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Abe Takatoshi
• Sawada Tomoaki
• Yoshioka Shingo

Classifications

• B32B7/05

  the layers not being connected over the whole surface, e.g. discontinuous connection or patterned connection (using interposed adhesives or bonding materials applied in spaced arrangements B32B7/14) · CPC title

• B32B2457/20

  Displays, e.g. liquid crystal displays, plasma displays · CPC title

• B32B2305/77

  Uncured, e.g. green · CPC title

• B32B27/08

  of synthetic resin · CPC title

• B32B2307/21

  Anti-static · CPC title