Injection molding process, apparatus and material for forming cured-in-place gaskets

1. A method for producing a gasket comprising:

providing an actinic radiation curable (meth)acrylate-functionalized poly(meth)acrylate composition;

providing an injection mold assembly defining an enclosed gasket-forming cavity and an injection port communicating with the cavity, the mold assembly comprising actinic radiation conducting optic fibers for permitting actinic radiation transmission therethrough;

injecting the composition into the cavity at a pressure of about 1,030 kPa (150 psig) or less to fill the cavity;

transmitting actinic radiation through the radiation-conducting optic fibers in a sufficient amount cure the composition in the mold assembly to form a gasket.

2. A method for producing a gasket comprising:

providing an actinic radiation curable (meth)acrylate-functionalized poly(meth)acrylate composition comprising a (meth)acrylate-terminated poly n-butyl acrylate;

providing an injection mold assembly defining an enclosed gasket-forming cavity and an injection port communicating with the cavity, the mold assembly comprising actinic radiation-conducting means for permitting actinic radiation transmission therethrough;

injecting the composition into the cavity at a pressure of about 1,030 kPa (150 psig) or less to fill the cavity;

transmitting actinic radiation through the radiation-conducting means in a sufficient amount cure the composition in the mold assembly to form a gasket.

3. The method of claim 2 , wherein the actinic radiation conducting means comprises a mold surface which transmits actinic radiation directly therethrough to cure the composition.

4. The method of claim 2 , wherein at least a portion of the actinic radiation-conducting means comprises a light-transmitting plastic or glass.

5. The method of claim 2 , wherein the poly(meth)acrylate composition includes at least one two monofunctional monomers present in a combined amount of about 8% to about 20% by weight of the total composition.

6. The method of claim 2 , wherein the mold assembly comprises an article of manufacture and the gasket is cured-in-place on the article of manufacture to provide an integral gasket thereon eliminating the need to separately form a gasket and subsequently place the gasket on the article of manufacture.

7. A method for producing a gasket comprising:

providing an actinic radiation curable (meth)acrylate-functionalized poly(meth)acrylate composition prepared from about 40% to 90% (meth)acrylate-functionalized poly(meth)acrylate polymer; from about 0.5% to about 50% reactive diluent; from about 0.5% to about 10% photoinitiator; and from about 0.5% to about 30% silica filler, wherein the percentages are based on weight percent of the total composition;

providing an injection mold assembly defining an enclosed gasket-forming cavity and an injection port communicating with the cavity, the mold assembly comprising actinic radiation-conducting means for permitting actinic radiation transmission therethrough;

injecting the composition into the cavity at a pressure of about 1,030 kPa (150 psig) or less to fill the cavity;

transmitting actinic radiation through the radiation-conducting means in a sufficient amount cure the composition in the mold assembly to form a gasket.

8. A method for producing an integral gasket bonded to an article of manufacture, comprising:

providing a first, actinic radiation opaque mold member comprising the article of manufacture having a gasket surface;

providing a second mold member having a surface defining a gasket-forming cavity and an injection port communicating with the cavity, the mold comprising actinic radiation-conducting means for permitting actinic radiation transmission therethrough and wherein the second mold member comprises a polymer liner abuttingly disposed on the second mold surface;

sealingly contacting the mold members so that the gasket-forming cavity is adjacent to the gasket surface;

injecting an actinic radiation curable composition prepared from a (meth)acrylate-functionalized poly(meth)acrylate material into the cavity at a pressure of about 1,030 kPa (150 psig) or less to fill the cavity;

transmitting actinic radiation through the radiation-conducting means in a sufficient amount to cure the composition in the mold to form a gasket integrally bonded to the gasket surface of the article of manufacture.

9. A method for producing an integral gasket bonded to an article of manufacture, comprising:

providing a first, actinic radiation opaque mold member comprising the article of manufacture having a gasket surface;

providing a second mold member having a surface and an injection, the second mold member comprising a portion permitting actinic radiation transmission therethrough;

sealingly contacting the mold members so that a gasket-forming cavity is formed adjacent to the gasket surface, the gasket-forming cavity fluidly connected to the injection port;

injecting an actinic radiation curable composition prepared from about 40% to about 90% by weight of the composition of (meth)acrylate-functionalized poly(meth)acrylate material; about 0.5% to about 50% by weight of the composition of reactive diluent; and about 0.5% to about 10% of the composition of photoinitiator into the cavity at a pressure of about 1,030 kPa (150 psig) or less to fill the cavity;

transmitting actinic radiation through the radiation-conducting means in a sufficient amount to cure the composition in the mold to form a gasket integrally bonded to the gasket surface of the article of manufacture.

10. The method of claim 9 , further comprising removing the second mold member from contact with the first mold member wherein the cured gasket remains bonded to the article gasket surface.

11. The method of claim 9 , wherein the article of manufacture comprises a portion of a vehicle.

12. The method of claim 9 , wherein the article of manufacture comprises a valve cover or an oil pan.

13. The method of claim 9 , wherein the curable composition has a viscosity of about 50 Pas (50,000 cPs) to about 100 kPa (100,000 cPs).

14. The method of claim 9 , wherein the second mold member comprises a polymer liner.

15. The method of claim 9 , wherein the second mold member surface defines a gasket-forming cavity.