Viscoelastic resin composition for vibration-damping material

• US 5,183,863 A
• Filed: 05/29/1992
• Issued: 02/02/1993
• Est. Priority Date: 05/31/1991
• Status: Expired due to Term

• Current Assignee: Nippon Steel Corporation, Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Nippon Steel Corporation, Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Kadowaki, Nobuo, Endoh, Hiroshi, Hirakouchi, Hiroshi, Nakamura, Masanori, Yatsuka, Takeshi
• Primary Examiner(s): WELSH JR, MAURICE
• Application Number:
  US07/890,116
• Time in Patent Office: 249 Days
• Field of Search: 525/438, 525/440, 525/444, 528/51, 528/81, 528/83, 528/89, 528/112, 528/115, 528/286, 528/296, 528/297, 528/304, 528/308
• US Class Current: 525/438
• CPC Class Codes: C08G 18/4202 Two or more polyesters of different physical or chemical nature C08G18/44 takes precedence
• CPC Class Codes: C08G 2350/00 Acoustic or vibration damping material
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 2666/18 Polyesters or polycarbonates according to C08L67/00 - C08L69/00; Derivatives thereof
• CPC Class Codes: C08L 63/00 Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: C08L 67/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds C08L67/06 takes precedence
• CPC Class Codes: F16F 9/006 characterised by the nature of the damping medium, e.g. biodegradable variable viscosity damping adjustment F16F9/53

Abstract

Disclosed herein is a viscoelastic resin composition for vibration-damping material which comprises (A) at least one amorphous polyester resin of low specific gravity in which more than 40 mol % of the dibasic acid moiety is of aromatic type, (B) at least one amorphous polyester resin of high specific gravity in which more than 80 mol % of the dibasic acid moiety is of aromatic type, and (C) at least one hardener selected from the group consisting of polyisocyanate compounds, epoxy group-containing compounds, and acid anhydrides, said consitutents (A) and (B) being in the ratio of from 90:10 to 30:70 by weight and differing from each other in specific gravity (at 30° C.) by 0.06 to 0.15 and also in molecular weight by more than 10000, with that of either of them being higher than 5000. This resin composition gives a vibration-damping material which exhibits improved vibration-damping properties, adhesive strength, formability, and heat resistance after forming.

Claims

1. A viscoelastic resin composition for a vibration damping material comprising (A) at least one low specific gravity amorphous polyester resins wherein 40 mol % or more of the dibasic acid component is an aromatic dicarboxylic acid, (B) at least one high specific gravity amorphous polyester resins wherein 80 mol % or more of the dibasic acid component is an aromatic dicarboxylic acid and (C) at least one hardener selected from the group consisting of polyisocyanate compounds, epoxy group-containing compounds and acid anhydrides, characterized in that the difference in molecular weight between (A) and (B) is 10,000 or more, the molecular weight of one of (A) and (B) is 5,000 or higher, the difference in specific gravity at 30°

C. between (A) and (B) is within the range of 0.06-0.15, and the weight ration (A);

(B) is within the range of 90;

10-30;

70.

2. A composition as claimed in claim 1 wherein the acid value of at least one of the low specific gravity amorphous polyester resin and high specific gravity amorphous polyester resin is 25 equivalents or more per ton of the resin.

3. A composition as claimed in claim 1 wherein the difference in specific gravity between the low specific gravity amorphous polyester resin and high specific gravity amorphous polyester resin is within the range from 0.07 to 0.15.

4. A composition as claimed in claim 3 wherein the said difference in specific gravity is within the range from 0.08 to 0.125.

5. A composition as claimed in claim 1 wherein the molecular weight of either one of the low specific gravity amorphous polyester resin and the high specific gravity amorphous polyester resin is 7,000 or higher.

6. A composition as claimed in claim 1 wherein the weight ratio of the (A) low specific gravity amorphous polyester resin and (B) high specific gravity amorphous polyester resin, i.e. (A):

(B), is 85;

15-50;

50.

7. A composition as claimed in claim 2 wherein the hardener comprises an epoxy group-containing compound and acid anhydride.

8. A composition as claimed in claim 7 wherein the amount of the hardener is 5-50 parts by weight per 100 parts by weight of the total polyester resin.

9. A composition as claimed in claim 8 wherein the acid anhydride contains two acid anhydride groups in one molecule.

10. A composition as claimed in claim 7 wherein the hardener further contains a phosphorus compound as a catalyst for epoxy ring opening reaction.

11. A composition as claimed in claim 10 wherein the phosphorus compound is a tertiary phosphine.