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US-20260125548-A1 - ENERGY SAVING, EXPANDABLE, PUMPABLE, ANTI-FLUTTER COMPOSITIONS FOR USE IN AUTOMOTIVE BODY-IN-WHITE (BIW) APPLICATIONS

US20260125548A1US 20260125548 A1US20260125548 A1US 20260125548A1US-20260125548-A1

Abstract

A low temperature curable anti-flutter composition which cures to form a cured product, including: (a) a first copolymer, wherein the first copolymer comprises a rubber having at least one nitrile functional group; and (b) a second copolymer, wherein the second copolymer comprises a rubber having styrene-butadiene functional groups, wherein the composition is a room temperature pumpable sealant which is capable of expanding and curing at temperatures below 140° C. in less than 15 minutes.

Inventors

  • Thanikaivelan Tindivanam Veeraraghavan
  • Karthikeyan Sengotaiyan
  • Senthilkumar Veeraraghavan

Assignees

  • Thanikaivelan Tindivanam Veeraraghavan
  • Karthikeyan Sengotaiyan
  • Senthilkumar Veeraraghavan

Dates

Publication Date
20260507
Application Date
20251105

Claims (20)

  1. 1 - 20 . (canceled)
  2. 21 . A low temperature curable anti-flutter composition, comprising: a pre-crosslinked butadiene-acrylonitrile copolymer rubber; a PVC homopolymer dispersion resin; a PVC homopolymer gelation resin; calcium oxide; an adhesion promoter; a curing accelerator; a blowing agent; a calcium carbonate filler; a precipitated calcium carbonate thixotropic agent; a wetting agent; conductive carbon black; an antioxidant; a linear nonyl phthalate plasticizer; a high solvating non-phthalate plasticizer; a triaryl phosphate plasticizer; wherein the composition is pumpable at room temperature; and wherein the composition cures at 140° C. in 15 minutes to produce volume expansion.
  3. 22 . The composition of claim 21 , wherein said pre-crosslinked butadiene-acrylonitrile copolymer rubber is present at 1.2 wt %.
  4. 23 . The composition of claim 22 , wherein said PVC homopolymer dispersion resin is present at 27.0 wt % and said PVC homopolymer gelation resin is present at 10.0 wt %.
  5. 24 . The composition of claim 23 , further comprising 0.1 wt % of an organic peroxide curing agent.
  6. 25 . The composition of claim 24 , wherein said composition exhibits a viscosity of 565 pascal-seconds at 25° C.
  7. 26 . The composition of claim 25 , wherein said calcium carbonate filler is present at 28.0 wt % and said precipitated calcium carbonate thixotropic agent is present at 5.0 wt %.
  8. 27 . The composition of claim 26 , wherein said composition produces 30% volume expansion when cured at 140° C. for 15 minutes.
  9. 28 . A method of forming an automotive anti-flutter seal, comprising the steps of: providing a composition comprising a pre-crosslinked butadiene-acrylonitrile copolymer rubber, a PVC resin, an organic peroxide curing agent, calcium oxide, an adhesion promoter, a curing accelerator, a blowing agent, calcium carbonate materials, a wetting agent, conductive carbon black, an antioxidant, and plasticizers; pumping said composition at room temperature through application equipment; and curing said composition at 140° C. for 15 minutes to form an expanded seal.
  10. 29 . The method of claim 28 , wherein said step of providing comprises mixing 1.2 wt % pre-crosslinked butadiene-acrylonitrile copolymer rubber with said PVC resin.
  11. 30 . The method of claim 29 , wherein said step of providing comprises combining 27.0 wt % PVC homopolymer dispersion resin with 10.0 wt % PVC homopolymer gelation resin.
  12. 31 . The method of claim 30 , wherein said step of pumping comprises maintaining said composition at a viscosity of 500-800 pascal-seconds.
  13. 32 . The method of claim 31 , wherein said step of curing produces an expanded seal exhibiting 30% volume expansion.
  14. 33 . The method of claim 32 , wherein said step of curing results in 100% cohesive failure when tested according to ASTM D1002.
  15. 34 . The method of claim 33 , wherein said step of providing further comprises adding 0.1 wt % organic peroxide curing agent.
  16. 35 . A low temperature curable anti-flutter composition, comprising: 1.2 wt % pre-crosslinked butadiene-acrylonitrile copolymer rubber; a PVC homopolymer resin totaling at least 30 wt %; an organic peroxide curing agent; calcium oxide; an adhesion promoter; a curing accelerator; a blowing agent; calcium carbonate materials totaling at least 25 wt %; a wetting agent; conductive carbon black; an antioxidant; plasticizers totaling at least 15 wt %; wherein the composition exhibits 100% cohesive failure when tested according to ASTM D1002 after curing at 140° C. for 15 minutes.
  17. 36 . The composition of claim 35 , wherein said PVC homopolymer resin comprises 27.0 wt % dispersion resin and 10.0 wt % gelation resin.
  18. 37 . The composition of claim 36 , wherein said calcium carbonate materials comprise 28.0 wt % calcium carbonate filler and 5.0 wt % precipitated calcium carbonate thixotropic agent.
  19. 38 . The composition of claim 37 , wherein said plasticizers comprise 10.0 wt % linear nonyl phthalate, 5.5 wt % high solvating non-phthalate plasticizer, and 5.5 wt % triaryl phosphate plasticizer.
  20. 39 . The composition of claim 38 , wherein said composition exhibits a viscosity of 565 pascal-seconds at 25° C.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 17/875,554, entitled “ENERGY SAVING, EXPANDABLE, PUMPABLE, ANTI-FLUTTER COMPOSITIONS FOR USE IN AUTOMOTIVE BODY-IN-WHITE (BIW) APPLICATIONS” filed Jul. 28, 2022, which is hereby incorporated herein by reference in its entirety, including all references cited therein. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not applicable. REFERENCE TO A SEQUENCE LISTING Not applicable. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to automotive sealants, and, more particularly, to anti-flutter sealants that are used to adhere to and isolate outer panels (e.g., hoods, A-pillars, B-pillars, C-pillars, roofs, doors, deck lids, etcetera) from inner reinforcement. These outer panels are required to adhere to steel, aluminum, metal alloys, and carbon fiber-reinforced polymer (CFRP) substrates. Anti-flutter sealants are commonly used in the automotive industry to seal or fill in the gaps between the body panels of the automobile. These anti-flutter sealants are routinely applied in areas where the frame of the automobile has joints (e.g., hoods, A-pillars, B-pillars, C-pillars, roofs, doors, deck lids, etcetera) to prevent and/or minimize water, dust, air intrusion, noise, vibration and corrosion. The present invention is directed to an automobile adhesive/sealant, and in particular to a low-temperature curing type anti-flutter sealant and the preparation thereof. The low temperature curing anti-flutter compositions of the present invention preferably comprise a nitrile copolymer rubber, such as a hydrogenated copolymer of an unsaturated nitrile and a hydrogenated copolymer of a conjugated diene, a cross-linked styrene butadiene rubber, a poly vinyl chloride (PVC) resin, a plasticizer, an adhesion promoter, a filler, a peroxide curing agent, a wetting agent, and a blowing agent. The anti-flutter sealant formulations of the present invention cure at low temperature in less time compared to conventional anti-flutter sealants, and they fulfill all the automotive test requirements, including, but not limited to, adhesion, expansion, elongation and long-term performance like corrosion, heat and moisture resistance. 2. Background Art Currently, in the automotive manufacturing process, the electrodeposition bake cycle is approximately 30-60 minutes at a temperature of approximately 340-400° F. Because of this, conventional sealants are developed and used which cure at elevated temperatures. The reason for this, is that the sealants are applied on the body parts of the car prior to the electrodeposition bake cycle. As such, the e-coat and sealants get baked at the same time. However, due to the high cost of energy and time emphasis on vehicle manufacturing, there is significant pressure within the automotive industry to reduce both the operating temperatures and manufacturing time. The automobile manufacturers are striving to complete the electrodeposition bake cycle in less than 30 minutes at a temperature of less than 300° F. Ideally, the automobile manufacturers are striving to complete the electrodeposition bake cycle in approximately 10-20 minutes at a temperature at or below 280-290° F. As such, curing of conventional anti-flutter sealants under these new conditions will be adversely affected. Currently available anti-flutter sealants need a minimum of 30 minutes at 340° F. to properly cure. The anti-flutter sealants of the present invention have been surprisingly effective and properly cure in approximately 15 minutes at a temperature of only 285° F.—and in some cases significantly lower. Simple energy consumption models show that lowering the oven set point temperatures by only 55° F. and reducing manufacturing time by as little as 10 minutes results in an energy savings of around 10-15%, which is not only significant, but critically important toward being environmentally responsible at a global level. Moreover, by lowering the curing time, more cars can be manufactured per hour, thereby reducing production costs. These and other objects of the present invention will become apparent in light of the present specification, claims, and drawings. SUMMARY OF THE INVENTION The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview, and is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. The automotive industry is striving to reduce vehicle weight toward increasing fuel economy and reducing emissions. The automobile manufacturers are using different substrates to reduce the weight of the automobile, such as aluminum and composites, in conjunction with steel to optimi