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Process and silicone encapsulant composition for molding small shapes

A composition, the technology of silicone, used in the direction of applications, home appliances, household components, etc.

Inactive Publication Date: 2008-04-16
DOW CORNING CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the past, injection molding was not acceptable in the industry because defects (e.g., cracks, air bubbles, and flow lines) were observed within the molded part and it was difficult to inject at molding process temperatures on the order of 100-3,000 centipoise (cps) low viscosity material

Method used

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  • Process and silicone encapsulant composition for molding small shapes
  • Process and silicone encapsulant composition for molding small shapes
  • Process and silicone encapsulant composition for molding small shapes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

Embodiment 1-manufacturing curved surface lens

[0044] According to the method of the present invention, curved lenses are manufactured using the injection molding equipment of FIG. 1 and the molds of FIGS. 2 and 3 . The mold was heated at the temperature (° C.) shown in Table 1. The addition curable organopolysiloxane resin composition is fed into the extruder 105 through the static mixer 104, and a certain amount of the obtained curable organopolysiloxane resin composition (in. 3 , cin) is fed into the component 110. The amounts used are shown in Table 1. This amount of curable organopolysiloxane resin composition contains 82.5 parts D Vi 10 D. 15 T Ph 75 , 10 parts M Vi D. Ph2 , 10 parts M Vi 3 T Ph ,M H 60 ,T Ph 40 , 0.013 parts of platinum catalyst and 0.10 parts of chemical formula HC≡C-C(Me) 2 -O 3 Platinum Catalyst Inhibitor of SiMe; where the subscript indicates the number of siloxane units, and the superscript indicates any monovalent group bonded t...

Embodiment 2

[0047] Using the process parameters in Table 2, the curved lens was manufactured according to the procedure of Example 1. The curable organopolysiloxane resin composition in Example 2 contained 82.5 parts of T Ph 0.75 Q 0.10 m Vi 0.15 , 8.9 parts Ph 2 Si(OSiMe 2 h) 2 , 5.9 PhSi (OSiMe 2 h) 3 , 1.01 parts bis-diphenylphosphinopropane and 5 ppm platinum catalyst. Comparative trials 1-4 show that some formulations can result in incomplete filling when the supply is too low, when the backpressure is too low, or both. Runs 5-18 showed that acceptable molded parts could be produced under a variety of process conditions.

Embodiment 3

[0048] Using the process parameters in Table 3, the curved lens was manufactured according to the procedure of Example 1. The organopolysiloxane resin composition in Example 3 contained 67.5 parts of DOW CORNING(R) SYLGARD(R) 184 Part A, 9.5 parts of DOW CORNING(R) SYLGARD(R) 184 Part B, 9.01 parts of Si(SiMe 2 CH==CH 2 ) 4 , MD 3.2 DH 5.8 M, and 13.9 MD 3.2 D. H 5.8 M. Comparative Runs 1-7 did not produce acceptable lenses because of air entrapment in the starting system. Runs 8-13 produced acceptable lenses, even in the presence of air bubbles. The quality of the lens is improved in this embodiment when the composition is processed and entrapped air is removed.

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Abstract

A process includes the steps of: 1) heating a mold at a temperature ranging from 100 DEG C to 200 DEG C; 2) feeding a silicone encapsulant composition including a mold release agent, where the composition has a viscosity ranging from 100 cps to 3,000 cps at operating temperatures of the process, to an assembly for preventing the silicone encapsulant composition from flowing backward out of the assembly; 3) injecting the silicone encapsulant composition from the assembly into a mold having a horizontal orientation and having a mold cavity through a gate, where the mold cavity has a top and a bottom, a vent is located at the top of the mold cavity, the vent comprises a channel 0.1 mm to 1 mm wide by 0.0001 mm to 0.001 mm deep, the gate is located at the bottom of the mold cavity, and injecting is performed at a pressure ranging from 1,000 psi to 10,000 psi for up to 5 seconds; 4) holding the silicone encapsulant composition at 1,000 psi to 10,000 psi for an amount of time sufficient to prevent the silicone encapsulant composition from flowing out of the mold cavity; 5) curing the product of step 4). Lenses for LED packages may be prepared by the process.

Description

[0001] cross reference [0001] This application claims the benefit of US Provisional Application Serial No. 60 / 684932, filed May 26, 2005, under 35.U.S.C. §119(e). US Provisional Application Serial No. 60 / 684932 is hereby incorporated by reference. technical field [0002] The present invention relates to methods of forming small profiles from silicone encapsulant compositions. The method is suitable for forming optical device components, such as lenses for light emitting diode (LED) packages, and vertical cavity surface emitting lasers (VCSELs). Background technique [0003] Using transfer molding or casting, the precise manufacture of optics components using silicone compositions is challenging due to long cycle times (on the order of minutes) and high waste content, e.g., up to 50% in these methods or higher curable silicone compositions can be disposed of as waste. In the past, injection molding was not acceptable in the industry because defects (e.g., cracks, air bu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L83/04G02B1/04
CPCB29D11/00009B29C67/246B29C45/0001C08L83/04B29K2083/005B29K2083/00B29L2031/747B29L2011/0016G02B1/04
Inventor M·巴哈德A·诺里斯L·弗里什
Owner DOW CORNING CORP