Shape memory film

• US 5,139,832 A
• Filed: 10/12/1989
• Issued: 08/18/1992
• Est. Priority Date: 10/14/1988
• Status: Expired due to Term

• Current Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Inventors: Fujimura, Hiroshi, Shimizu, Makoto, Hayashi, Shunichi
• Primary Examiner(s): Sluby, P. C.
• Application Number:
  US07/420,565
• Time in Patent Office: 1,041 Days
• Field of Search: 428/411.1, 428/423.1, 428/35.5
• US Class Current: 428/35.5
• CPC Class Codes: B29C 61/003 characterised by the choice of material
• CPC Class Codes: B29K 2009/06 SB polymers, i.e. butadiene-styrene polymers
• CPC Class Codes: B29K 2075/00 Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2995/0026 Transparent
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/3206 aliphatic
• CPC Class Codes: C08G 18/3215 containing aromatic groups or benzoquinone groups
• CPC Class Codes: C08G 18/4238 derived from dicarboxylic acids and dialcohols
• CPC Class Codes: C08G 18/4825 Polyethers containing two hydroxy groups C08G18/4833 - C08G18/5096 take precedence
• CPC Class Codes: C08G 18/4879 containing aromatic groups
• CPC Class Codes: C08G 2250/00 Compositions for preparing crystalline polymers
• CPC Class Codes: C08G 2280/00 Compositions for creating shape memory
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/1345 Single layer [continuous layer]
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]

Abstract

A shape memory film formed from a shape memory transparent polymer, said shape memory film being capable of remembering a basic shape such as plane configuration and dead folds, taking on a second shape when the basic shape is modified (by changing the plane configuration and adding dead folds, twists, three-dimensional configurations, etc.) at a temperature higher than the glass transition point of the polymer and lower than the molding temperature of the polymer, and having the second shape set when cooled to a temperature lower than the glass transition point while being kept in the second shape; and a method of using said shape memory film by setting the second shape and subsequently heating the film to a temperature higher than the glass transition point, thereby causing the film to restore its basic shape.

Claims

1. A shape memory polyurethane polymer consisting of a difunctional diisocyanate, difunctional polyol and difunctional chain-extender containing active hydrogen in the form of a film, said film having been formed into a first shape at a temperature higher than the glass transition point, and then having been formed into a second shape at a temperature above the glass transition point and maintained in said second shape and cooled to a temperature below the glass transition point whereby the film maintains said second shape, said film being capable of resuming said first shape upon heating at a temperature higher than the glass transition point wherein said polyurethane contains almost equal amounts of NCO groups and OH groups at the terminals of the polymer chains and has a glass transition point in the range of -50°

to 60°

C. and a crystallinity of 3 to 50 wt. %.

2. A shape memory polymer as claimed in claim 1 wherein said difunctional is cyanate, difunctional polyol and difunctional chain-extender are polymerized in molecular ratios 2.00˜

1.10;

1.00;

1.00˜

0.10.

3. A packaging bag made from the polymer of claim 1.

4. The polymer of claim 1 wherein the first shape has one or more folds in it and the second shape has additional folds, twists, concavities or convexities.