Adhesively bonded engine and transmission parts

• US 20050061280A1
• Filed: 09/17/2004
• Published: 03/24/2005
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Jialanella, Gary L., Courter, David M.
• Granted Patent: US 7,556,002 B2
• Time in Patent Office: Days
• US Class Current: 123/90.380
• CPC Class Codes: C08G 59/66 Mercaptans
• CPC Class Codes: C08G 75/02 Polythioethers
• CPC Class Codes: C09J 181/02 Polythioethers; Polythioether-ethers

Abstract

In one embodiment the invention is a system and method for bonding parts to an engine or a transmission which comprises contacting with the part or the location of the engine or the transmission to which the part is to be attached an adhesive comprising a polythiol ether having two or more reactive groups capable of reacting with a curing agent and a curing agent for the polythiol ether and thereafter contacting the part with the engine or transmission such that the adhesive is disposed between them and curing the adhesive.

Claims

1. A valve cover assembly comprising a valve cover having a mating surface adapted to be attached to a cylinder head of an internal combustion engine having a continuous bead of an adhesive disposed on the perimeter of the mating surface of the valve cover wherein the adhesive comprises a polythiol ether having two or more reactive groups capable of reacting with a crosslinking agent and a crosslinking agent.

2. A valve cover assembly according to claim 1 wherein the valve cover does not have bolt holes which have a primary function of holding the valve cover to the cylinder head.

3. A valve cover assembly according to claim 1 wherein the adhesive is a two-part adhesive comprising in one part a polythiol ether having two or more reactive groups and in another part a curing agent for the polythiol ether and an accelerator for the cure of the polythiol ether.

4. A valve cover assembly according to claim 3 wherein the reactive groups are one or more of hydroxyl, primary or secondary amino, mercapto groups.

5. A valve cover according to claim 3 wherein the curing agent is one or more of polyepoxides, isocyanates, acrylates or vinyl containing compound.

6. A valve cover assembly according to claim 4 wherein the adhesive composition further comprises a filler.

7. An engine assembly comprising one or more valve covers having mating surfaces and one or more cylinder heads having mating surfaces adapted to fit to the mating surfaces of the valve covers wherein each valve cover is adhesively bonded to a cylinder head wherein a continuous layer of adhesive is disposed between the mating surfaces of each valve cover and the cylinder head to which each valve cover is bonded, wherein the continuous layer of adhesive forms a seal between the mating surface of each valve cover and cylinder head pair such that the transmission of gasses and liquids between each valve cover and cylinder head pair where the mating surfaces are in contact is significantly reduced or prevented wherein the adhesive comprises a polythiol ether having two or more reactive groups capable of reacting with a crosslinking agent and a crosslinking agent.

8. An engine assembly according to claim 7 wherein the adhesive is a two part adhesive comprising in one part a polythiol ether having two or more reactive groups and in another part a curing agent for the polythiol ether and an accelerator for the cure of the polythiol ether.

9. An engine assembly according to claim 8 wherein the reactive groups are one or more of hydroxyl, primary or secondary amino, mercapto groups the reactive groups are one or more of hydroxyl, primary or secondary amino, mercapto groups.

10. An engine assembly according to claim 8 wherein the curing agent is one or more of polyepoxides, isocyanates, acrylates, vinyl containing compounds or a mixture thereof.

11. An engine assembly according to claim 9 wherein the adhesive composition further comprises a filler.

12. An engine assembly according to claim 7 wherein the adhesive composition exhibits a lap shear strength of about 200 psi or greater 20 minutes after assembly.

13. An engine assembly according to claim 8 wherein the adhesive composition is cured by heat.

14. An engine assembly according to claim 13 wherein the cured adhesive exhibits a lap shear strength of about 450 psi or greater after cure.

15. A method for bonding a valve cover to a cylinder head comprising

a) applying to the valve cover or the cylinder head, wherein the valve cover has a mating surface adapted to be mated with a mating surface of a cylinder head, a continuous bead or film of adhesive along the entire mating surface of the valve cover or the cylinder head;

b) contacting the mating surface of the valve cover with the mating surface of the cylinder head such the continuous bead or film of adhesive is disposed between the mating surfaces of the valve cover and the cylinder head;

c) curing the adhesive to form a permanent bond between the mating surfaces of the valve cover and the cylinder head herein the adhesive forms a seal between the valve cover and the cylinder head,

wherein the adhesive comprises a polythiol ether having two or more reactive groups capable of reacting with a crosslinking agent and a crosslinking agent and the adhesive has sufficient strength after application to hold the one or more valve covers in place.

16. A method according to claim 15 wherein the adhesive is cured by exposure to a heat source.

17. A method according to claim 16 wherein the adhesive is cured by the heat of the engine during operation of the engine.

18. The method of claim 16 wherein the valve cover mating surface and the cylinder head mating surface are maintained in contact, with the adhesive bead or film disposed between them, through the use of a mechanical fastening means other than bolts.

19. A composition comprising

A) in one part

i) a polythiol ether having two or more reactive groups and an equivalent of about 600 to about 5000;

ii) a room temperature cure accelerator for the reaction of the polythiol ether with a curing agent;

B) in a second part

iii) a curing agent for the polythiol ether;

iv) a reactive diluent, reactive with the polythiol ether or the curing agent; and

v) a carbon black having an iodine number of about 82 to about 92 mg/g and an oil absorption number of about 100 to about 110 g/cc.

20. A method of bonding a part to an automobile engine or transmission which comprises contacting an adhesive comprising a polythiol ether having, two or more reactive groups and a curing agent for the polythiol ether with one or both of the part or the automobile engine or transmission contacting the part and the engine or transmission with the adhesive located between the parts and curing the adhesive so that the joint between the part and the engine or transmission is sealed.