Cured composite, processes and composition

• US 5,485,541 A
• Filed: 05/09/1994
• Issued: 01/16/1996
• Est. Priority Date: 06/15/1993
• Status: Expired due to Term

• Current Assignee: Energy Focus, Inc.
• Original Assignee: Rohm and Haas Company (Dow, Inc.)
• Inventors: Work, William J., Holy, Norman L., Jerman, Robert E., Bigley, Andrew B. W. Jr., Johnson, Phelps B., Daecher, Jeffrey L.
• Primary Examiner(s): THURLOW, JEFFERY
• Application Number:
  US08/236,381
• Time in Patent Office: 617 Days
• Field of Search: 264/1.27, 264/1.28, 264/1.29, 264/1.24, 264/1.60, 385/141, 385/123, 385/143, 425/131.1, 425/114, 156/244.12
• US Class Current: 385/141
• CPC Class Codes: B29C 2035/0822 using IR radiation
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 48/304 specially adapted for bringing together components, e.g. melts within the die
• CPC Class Codes: B29C 48/34 Cross-head annular extrusion nozzles, i.e. for simultaneously receiving moulding material and the preform to be coated
• CPC Class Codes: B29C 48/91 Heating, e.g. for cross linking
• CPC Class Codes: B29C 48/911 Cooling
• CPC Class Codes: B29C 48/919 using a bath, e.g. extruding into an open bath to coagulate or cool the material
• CPC Class Codes: B29C 69/00 Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore B29C48/001 takes precedence
• CPC Class Codes: B29D 11/00663 Production of light guides
• CPC Class Codes: B29K 2033/08 Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate
• CPC Class Codes: B29K 2105/0085 Copolymers
• CPC Class Codes: B29K 2105/24 crosslinked or vulcanised
• CPC Class Codes: B29K 2105/246 Uncured, e.g. green
• CPC Class Codes: B29K 2301/10 Thermosetting resins
• CPC Class Codes: B29L 2011/0075 Light guides, optical cables

Abstract

A process for producing a cured composite and flexible light pipe, in which a molten cladding polymer and a crosslinkable core mixture are concurrently and coaxially extruded through a core mixture delivery tube of a coextrusion die, the extruded tubular cladding is filled with the extruded crosslinkable core mixture, and the crosslinkable core mixture is cured within the tubular cladding.

Claims

1. A process for producing a cured composite comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten cladding polymer through an annular channel of a coextrusion die to form an extruded tubular cladding, and

ii.) a synthesized crosslinkable core mixture comprising from about 72 to about 99.8 weight percent C₁ -C₁₈ alkyl acrylate and C₁ -C₁₈ alkyl methacrylate, through a core mixture delivery tube of the coextrusion die to form an extruded crosslinkable core mixture within the circumference of the extruded tubular cladding;

b) filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the crosslinkable core mixture within the tubular cladding after filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture.

2. The process of claim 1 wherein steps a), b) and c) are continuous.

11. The process of claim 1 further comprising the step of sheathing the extruded tubular cladding with a sheathing polymer simultaneously with, or subsequently to, filling the extruded tubular cladding with the extruded crosslinkable core mixture.

3. A process for producing light pipe comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten fluoropolymer through an annular channel of a coextrusion die to form an extruded tubular fluoropolymer cladding, and

ii.) a synthesized crosslinkable core mixture comprising from about 72 to about 99.8 weight percent C₁ -C₁₈ alkyl acrylate and C₁ -C₁₈ alkyl methacrylate, through a core mixture delivery tube of the coextrusion die to form an extruded crosslinkable core mixture within the circumference of the extruded tubular fluoropolymer cladding;

b) filling and contacting of the extruded tubular fluoropolymer cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the extruded crosslinkable core mixture within the extruded tubular fluoropolymer cladding wherein the cured extruded crosslinkable core mixture and the extruded tubular fluoropolymer cladding are in substantially complete contact after filling the extruded tubular cladding with the extruded crosslinkable core mixture.

4. The process of claim 3 wherein steps a), b) and c) are continuous.

5. The process of claim 3 wherein the crosslinkable core mixture comprises:

a) from about 90 to about 99.9 weight percent, based on the crosslinkable core mixture weight, of an uncrosslinked copolymer having weight average molecular weight from about 2,000 to about 250,000 daltons, the uncrosslinked copolymer comprising;

i) from about 80 to about 99.9 weight percent, based on the uncrosslinked copolymer weight, of one or more C₁ -C₁₈ alkyl acrylate selected from methyl acrylate, ethyl acrylate, normal butyl acrylate, and 2-ethylhexyl acrylate, and one or more C₁ -C₁₈ alkyl methacrylate selected from methyl methacrylate, ethyl methacrylate, normal butyl methacrylate, dodecyl methacrylate, and 2-ethylhexyl methacrylate.

ii) from about 0.1 to about 20 weight percent, based on the uncrosslinked copolymer weight, of a functionally reactive monomer; and

iii) from 0 to about 10 weight percent, based on the uncrosslinked copolymer weight, of a refractive index increasing monomer selected from styrene, benzyl acrylate, benzyl methacrylate, phenylethyl acrylate or phenylethyl methacrylate; and

b) from about 0.1 to about 10 weight percent, based on the crosslinkable core mixture weight, of a reactive additive.

6. The process of claim 5 wherein

a) the uncrosslinked copolymer molecular weight is from about 10,000 to about 150,000 daltons;

b) the functionally reactive monomer is selected from hydroxyethyl acrylate, hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, or mixtures of these; and

c) the reactive additive is selected from a diglycidyl ether, a dilactone, an aliphatic diisocyanate, a polycarboxylic acid, or an anhydride.

7. The process of claim 5 wherein

a) the uncrosslinked copolymer molecular weight is from about 10,000 to about 150,000 daltons;

b) the functionally reactive monomer is glycidyl acrylate or glycidyl methacrylate; and

c) the reactive additive is selected from an anhydride, a polycarboxylic acid, a diol or a polyol.

8. The process of claim 5 wherein

a) the uncrosslinked copolymer molecular weight is from about 10,000 to about 150,000 daltons;

b) the functionally reactive monomer is used at a level of from about 0.15 to about 12 weight percent and is selected from 2-methacryloxyethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, or mixtures of these; and

c) the reactive additive is water and a silane condensation reaction catalyst.

9. The process of claim 8 wherein

a) the C₁ -C₁₈ alkyl acrylate bulk monomer unit is methyl acrylate, ethyl acrylate, or normal butyl acrylate, or mixtures of these, and the C₁ -C₁₈ alkyl methacrylate bulk monomer is methyl methacrylate, butyl methacrylate, or ethyl methacrylate, or mixtures of these;

b) the functionally reactive monomer is 3-methacryloxypropyltrimethoxysilane or vinyltrimethoxysilane; and

c) the silane condensation reaction catalyst is a dialkyltin dicarboxylate.

10. The process of claim 9 further wherein the uncrosslinked copolymer is derived from about 94 to about 98 weight percent ethyl acrylate and from about 2 to about 6 weight percent of 3-methacryloxypropyltrimethoxysilane, and the silane condensation reaction catalyst is dibutyltin diacetate.

12. The process of claim 3 further comprising the step of sheathing the extruded tubular fluoropolymer cladding with a sheathing polymer simultaneously with, or subsequently to, filling the extruded tubular fluoropolymer cladding with the extruded crosslinkable core mixture.

13. The process of claim 3 wherein an exit outside diameter of the core mixture delivery tube is from about 1 to about 4 times a diameter of the cured core.

14. The process of claim 3 wherein an inside diameter of the core mixture delivery tube is from about 0.75 to about 3 times a diameter of the cured core.

15. The process of claim 3 wherein the coextrusion die has an annular channel exit gap width of from about 1 to about 20 times a thickness of the extruded tubular fluoropolymer cladding.

16. The process of claim 3 having a distance between a cooling bath surface and an exit of the core mixture delivery tube of less than 20 times a diameter of the cured core.

17. The process of claim 3 having a distance between an outer die block and a cooling bath surface of from about 1 to about 20 times a diameter of the cured core.

18. The process of claim 3 wherein the coextrusion die has an annular channel diameter of from about 1 to about 15 times a diameter of the cured core.

19. A flexible light pipe product by the process of claim 3.

20. A flexible light pipe product by the process of claim 3 having good light transmittance, wherein the diffuse white light transmission loss is less than or equal to 1.0 decibel per meter, and wherein the differential transmission loss between light wavelengths of 400 nm to 600 nm is equal to or less than 1.0 decibel per meter as measured by a "cut-back" interference filter method.

21. A flexible light pipe product by the process of claim 3 having good thermal stability, wherein a change in the differential transmission loss between light wavelengths of 400 nm to 600 nm is equal to or less than 0.5 decibel per meter after 50 days of exposure to a temperature of 90°

C., as measured by a non-destructive interference filter method.

22. A flexible light pipe product by the process of claim 3 having good flexibility, wherein the product, at 20°

C., survives without core fracture a 180°

bend at a bend radius which is less than or equal to five times the diameter of the cured core.

23. A flexible light pipe product by the process of claim 3 wherein the product has good hardness properties, wherein the Shore "A" hardness is less than 90 after 50 days of exposure at 120°

C.

24. A flexible light pipe product by the process of claim 3 wherein the product has good light transmittance wherein the differential transmission loss between light wavelengths of 400 nm to 600 nm is equal to or less than 1.0 decibel per meter as measured by a "cut-back" interference filter method;

good thermal stability, wherein a change in the differential transmission loss between light wavelengths of 400 nm to 600 nm is equal to or less than 0.5 decibel per meter after 50 days of exposure to a temperature of 90°

C., as measured by a non-destructive interference filter method;

good flexibility, wherein the product, at 20°

C., survives without core fracture a 180°

bend at a bend radius which is less than or equal to five times the diameter of the cured core; and

good hardness properties, wherein the Shore "A" hardness is less than 90 after 50 days of exposure at 120°

C.

25. A process for producing flexible light pipe comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten fluoropolymer through an annular channel of a coextrusion die to form an extruded tubular fluoropolymer cladding, and

ii.) a synthesized crosslinkable core mixture comprising from about 72 to about 99.8 weight percent C₁ -C₁₈ alkyl acrylate and C₁ -C₁₈ alkyl methacrylate, through a core mixture delivery tube of the coextrusion die to form an extruded crosslinkable core mixture within the circumference of the extruded tubular fluoropolymer cladding;

b) filling and contacting of the extruded tubular fluoropolymer cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the extruded crosslinkable core mixture within the extruded tubular fluoropolymer cladding wherein the cured extruded crosslinkable core mixture and the extruded tubular fluoropolymer cladding are in substantially complete contact after filling the extruded tubular cladding with the extruded crosslinkable core mixture.

26. The synthesized crosslinkable core mixture of claim 25 wherein the glass transition temperature is equal to or lower than the use temperature of the light pipe being produced.

27. The synthesized crosslinkable core mixture of claim 25 wherein the glass transition temperature is equal to or lower than 20°

C.

28. The synthesized crosslinkable core mixture of claim 25 wherein the glass transition temperature is equal to or lower than 0°

C.

29. The synthesized crosslinkable core mixture of claim 25 wherein the glass transition temperature is equal to or lower than -10°

C.

30. The synthesized crosslinkable core mixture of claim 25 wherein the glass transition temperature is equal to or lower than -20°

C.

37. The process of claims 31, 33, or 25 wherein the molten fluoropolymer is a terpolymer of vinylidene fluoride (VDF), tetrafluoroethylene (TFE) and hexafluoropropylene (HFP).

38. A flexible light pipe by the process of claim 37.

31. A process for producing light pipe comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten fluoropolymer through an annular channel of a coextrusion die to form an extruded tubular fluoropolymer cladding, and

ii.) a synthesized crosslinkable core mixture comprising;

a. from about 90 to about 99.9 weight percent, based on the crosslinkable core mixture weight, of an uncrosslinked copolymer having weight average molecular weight from about 2,000 to about 250,000 daltons, the uncrosslinked copolymer comprising;

i) from about 80 to about 99.9 weight percent, based on the uncrosslinked copolymer weight, of a bulk monomer unit selected from a C₁ -C₄ alkyl methacrylate, or mixtures thereof,

ii) from about 0.1 to about 20 weight percent, based on the uncrosslinked copolymer weight, of a functionally reactive monomer, and

iii) from 0 to about 10 weight percent, based on the uncrosslinked copolymer weight, of a refractive index increasing monomer selected from styrene, benzyl acrylate, benzyl methacrylate, phenylethyl acrylate or phenylethyl methacrylate; and

iv) a plasticizer of from about 1 to about 50 weight percent, based on the crosslinkable core mixture;

b) filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the extruded crosslinkable core mixture within the extruded tubular fluoropolymer cladding after filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture wherein the cured extruded crosslinkable core mixture and the extruded tubular fluoropolymer cladding are in substantially complete contact.

32. The process of claim 31 wherein one or more C₁ -C₄ alkyl methacrylates are selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, and iso-butyl methacrylate.

33. A process for producing light pipe comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten fluoropolymer through an annular channel of a coextrusion die to form an extruded tubular fluoropolymer cladding, and

ii.) a synthesized crosslinkable core mixture comprising;

a. from about 90 to about 99.9 weight percent, based on the crosslinkable core mixture weight, of an uncrosslinked copolymer having weight average molecular weight from about 2,000 to about 250,000 daltons, the uncrosslinked copolymer comprising;

i) from about 80 to about 99.9 weight percent, based on the uncrosslinked copolymer weight, of a bulk monomer unit selected from a C₄ -C₁₈ alkyl methacrylate, or mixtures thereof,

ii) from about 0.1 to about 20 weight percent, based on the uncrosslinked copolymer weight, of a functionally reactive monomer, and

iii) from 0 to about 10 weight percent, based on the uncrosslinked copolymer weight, of a refractive index increasing monomer selected from styrene, benzyl acrylate, benzyl methacrylate, phenylethyl acrylate or phenylethyl methacrylate;

b) filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the extruded crosslinkable core mixture within the extruded tubular fluoropolymer cladding after filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture wherein the cured extruded crosslinkable core mixture and the extruded tubular fluoropolymer cladding are in substantially complete contact.

34. The process of claim 33 wherein one or more C₄ -C₁₈ alkyl methacrylates are n-butyl methacrylate, iso-butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, isodecyl methacrylate, 2-ethylhexyl methacrylate and stearyl methacrylate.

35. A process for producing a cured composite comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten cladding polymer through an annular channel of a coextrusion die to form an extruded tubular cladding, and

ii.) a synthesized crosslinkable core mixture comprising from about 72 to about 99.8 weight percent polyester, amorphous polyolefin or olefin copolymer through a core mixture delivery tube of the coextrusion die to form an extruded polymer core mixture within the circumference of the extruded tubular cladding;

b) filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the crosslinkable core mixture within the tubular cladding after filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture.

36. A process for producing a cured composite comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten cladding polymer through an annular channel of a coextrusion die to form an extruded tubular cladding, and

ii.) a synthesized crosslinkable core mixture through a core mixture delivery tube of the coextrusion die to form an extruded crosslinkable core mixture within the circumference of the extruded tubular cladding;

b) filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the crosslinkable core mixture within the tubular cladding after filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture.

39. A process for producing flexible light pipe comprising the steps of:

a) concurrently and coaxially extruding;

i.) a molten fluoropolymer through an annular channel of a coextrusion die to form an extruded tubular fluoropolymer cladding, wherein the molten fluoropolymer is a terpolymer of vinylidene fluoride (VDF), tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), and

ii.) a synthesized crosslinkable core mixture comprising from about 72 to about 99.8 weight percent, based on the uncrosslinked copolymer weight, C₁ -C₁₈ alkyl acrylates, through a core mixture delivery tube of the coextrusion die to form an extruded crosslinkable core mixture within the circumference of the extruded tubular cladding;

b) filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture after exiting the coextrusion die; and

c) curing the extruded crosslinkable core mixture within the extruded tubular fluoropolymer cladding after filling and contacting the extruded tubular cladding with the extruded crosslinkable core mixture wherein the cured extruded crosslinkable core mixture and the extruded tubular fluoropolymer cladding are in substantially complete contact.

40. The process of claim 39 wherein steps a), b), and c) are continuous.

41. A flexible light pipe product by the process of claims 39 or 40.