Method of using mold release agents

• US 5,399,310 A
• Filed: 03/23/1993
• Issued: 03/21/1995
• Est. Priority Date: 03/23/1993
• Status: Expired due to Fees

• Current Assignee: Loctite Corporation (Henkel AG & Co KGaA)
• Original Assignee: Dexter Corp. (Thermo Fisher Scientific Incorporated)
• Inventors: Martin, David L., Payne, Jeffrey S.
• Primary Examiner(s): Vargot, Mathieu D.
• Application Number:
  US08/035,736
• Time in Patent Office: 728 Days
• Field of Search: 264/130, 264/338, 264/300, 264/51, 264/328.6, 106/38.24, 106/38.7, 106/243
• US Class Current: 264/338
• CPC Class Codes: B29C 33/62 based on polymers or oligomers
• CPC Class Codes: B29C 39/02 for making articles of definite length, i.e. discrete articles
• CPC Class Codes: B29C 67/246 Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM] casting monomers B29C39/006, mixing construction B29B7/74

Abstract

Mold release agents and methods for molding plastics are provided. They are especially applicable to polyurethane-based reaction injection molding (RIM) systems. The mold release agent includes the lithium, sodium, or potassium salt, or a mixture thereof, of an oligomer of monomeric units or a mixture of said oligomers, the monomeric units being selected from the group consisting of carboxylic fatty acids having at least 14 carbon atoms, preferably 14 to 24 carbon atoms, the salt of the oligomer preferably being soluble in water or water/alcohol. Preferably, the Li and Na salts of C₃₆ and C₄₄ dicarboxylic fatty acids are used. Preferred embodiments of the present invention permit the use of water without alcohol in the formulation.

Claims

1. A method for molding a plastic comprising coating a mold surface with a mold release agent, permitting said coating to dry, inserting a liquid plastic into said coated mold, allowing the liquid plastic to solidify, and releasing the resulting solid plastic from said mold, said mold release agent comprising an oligomeric salt agent and a diluent, said oligomeric salt agent being the lithium, sodium, or potassium salt, or a mixture thereof, of an oligomer of monomeric units or a mixture of said oligomers, the monomeric units being selected from the group consisting of C₁₄ to C₂₄ carboxylic fatty acids.

2. The method of claim 1, wherein said plastic is selected from the group consisting of polyurethane, polyisocyanurate, polyurea, and combinations thereof.

3. The method of claim 1, said mold release agent including less than about 0.03% alcohol by weight.

4. The method of claim 3, at least 70% by weight of said oligomeric salt agent being the lithium or sodium salt, or a mixture thereof, of a dimer of monomeric units or a mixture of said dimers, the monomeric units being selected from the group consisting of C₁₈ and C₂₂ carboxylic fatty acids.

5. The method of claim 3, at least 70% by weight of said oligomeric salt agent being the lithium salt of a dimer of monomeric units or a mixture of said dimers, the monomeric units being selected from the group consisting of C₁₈ and C₂₂ carboxylic fatty acids.

6. The method of claim 3, the mold release agent further comprising a surfactant in a concentration of about 0.01-0.5% by weight.

7. The method of claim 4, the mold release agent further comprising a surfactant in a concentration of about 0.01-0.5% by weight.

8. The method of claim 5, the mold release agent further comprising a surfactant in a concentration of about 0.01-0.5% by weight.

9. The method of claim 1, wherein the mold release agent used to coat the mold surface is at ambient temperature.

10. The method of claim 1, said oligomeric salt agent being at least 50% by weight of the solids of said mold release agent.

11. A method for molding a plastic comprising coating a mold surface with a mold release agent, permitting said coating to dry, inserting a liquid plastic into said coated mold, allowing the liquid plastic to solidify, and releasing the resulting solid plastic from said mold, said mold release agent comprising an oligomeric salt agent, said oligomeric salt agent being an effective salt, or a mixture of effective salts, of an oligomer of monomeric units or a mixture of said oligomers, the monomeric units being selected from the group consisting of carboxylic fatty acids having at least 14 carbon atoms, said oligomeric salt agent being soluble in water or water/alcohol, said effective salt being effective to solubilize said oligomeric salt agent in water or water/alcohol.

12. The method of claim 11, wherein said an effective salt is the lithium, sodium, or potassium salt, and said mixture of effective salts is a mixture of salts selected from the group consisting of the lithium, sodium, and potassium salts.

13. The method of claim 11, said mold release agent further comprising a diluent, said diluent being selected from the group consisting of water, alcohol, water/alcohol, and water/glycol ether.

14. The method of claim 13, said oligomeric salt agent being at least 50% by weight of the solids of said mold release agent.

15. The method of claim 13, said oligomeric salt agent being present in said diluent in a concentration of about 0.05-10% by weight.

16. The method of claim 13, at least 70% by weight of said oligomeric salt agent being the lithium or sodium salt, or a mixture thereof, of a dimer of monomeric units or a mixture of said dimers, the monomeric units being selected from the group consisting of C₁₈ and C₂₂ carboxylic fatty acids.

17. The method of claim 13, said mold release agent including less than about 0.03% alcohol by weight.

18. The method of claim 17, said mold release agent further comprising a surfactant in a concentration of about 0.01-0.5% by weight.

19. The method of claim 11, said oligomeric salt agent being completely soluble in water at ambient temperature at a concentration of 3.5% by weight.

20. The method of claim 11, wherein the mold release agent used to coat the mold surface is at ambient temperature.

21. The method of claim 11, wherein said mold release agent consists essentially of said oligomeric salt agent and a diluent.

22. The method of claim 21, wherein said oligomeric salt agent is present in said diluent in a concentration of about 0.05-10% by weight.

23. The method of claim 21, wherein said diluent consists essentially of water.

24. The method of claim 21, said mold release agent further consisting essentially of a surfactant.

25. The method of claim 24, wherein said diluent consists essentially of water.

26. The method of claim 11, wherein said plastic is selected from the group consisting of polyurethane, polyisocyanurate, polyurea, and combinations thereof.