Claims
- 1. The method of making a unitary shaped laminate comprising at least one external layer of a polyvinylidene fluoride resin, a layer of a thermoplastic resin incompatible with polyvinylidene fluoride, and a layer of polyalkyl methacrylate resin intermediate and firmly adhered to said polyvinylidene fluoride and thermoplastic resin layers; said layers being blended at their interfaces only, comprising the steps of bringing molten streams of said resins into intimate contact with each other to form the laminate shape desired and then cooling said laminate.
- 2. The method according to claim 1 wherein said streams of resins are extruded through a single die to form a laminate of the shape desired and said streams are brought into intimate contact with each other at the latest point at the exit orifice of said die.
- 3. The method according to claim 1 or 2, wherein the temperature of the die is maintained between about 180.degree. to 280.degree. C.
- 4. The method according to claim 1 or 2, wherein said polyvinylidene fluoride is selected from homopolymers of polyvinylidene fluoride, copolymers containing at least 70% by weight of polyvinylidene fluoride, or mixtures of polyvinylidene fluoride with other polymers and said polyvinylidene fluoride resin having, at 200.degree. C., an apparent viscosity, in poises, between the minimum and maximum values for at least two of the velocity gradients, in sec.sup.-1, set forth below:
- ______________________________________Velocity Gradient Apparent Viscosity Valuessec.sup.-1 Minimum Maximum______________________________________3.54 30 .times. 10.sup.3 200 .times. 10.sup.311.81 18 .times. 10.sup.3 93 .times. 10.sup.335.4 11 .times. 10.sup.3 47 .times. 10.sup.3118 6.5 .times. 10.sup.3 21 .times. 10.sup.3354 3.9 .times. 10.sup.3 10 .times. 10.sup.31181 2.3 .times. 10.sup.3 4.5 .times. 10.sup.3______________________________________
- 5. The method according to claim 1 or 2 wherein the polyalkyl methacrylate resin is polymethyl methacrylate having a viscosity, in poises, at 200.degree. C., between the minimum and maximum values for any given viscosity gradient, in sec.sup.-1, set forth below:
- ______________________________________Velocity gradient Apparent viscosity values in poisesec.sup.-1 minimum maximum______________________________________3.54 100 .times. 10.sup.3 500 .times. 10.sup.311.81 50 .times. 10.sup.3 280 .times. 10.sup.335.4 25 .times. 10.sup.3 150 .times. 10.sup.3118 13 .times. 10.sup.3 80 .times. 10.sup.3354 7 .times. 10.sup.3 50 .times. 10.sup.31181 3.5 .times. 10.sup.3 30 .times. 10.sup.3______________________________________
Priority Claims (2)
Number |
Date |
Country |
Kind |
78 27361 |
Sep 1978 |
FRX |
|
79 12952 |
May 1979 |
FRX |
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Parent Case Info
This is a division, of Application Ser. No. 71,675, filed Aug. 31, 1979, now U.S. Pat. No. 4,317,860.
US Referenced Citations (11)
Foreign Referenced Citations (3)
Number |
Date |
Country |
3449 |
Aug 1979 |
EPX |
2187517 |
Feb 1974 |
FRX |
53-60242 |
May 1978 |
JPX |
Non-Patent Literature Citations (1)
Entry |
"Coextruded Films-Process and Properties", Polymer Plastics Technology and Engineering, vol. 3, pp. 40-68, J. Guillotte, 1974. |
Divisions (1)
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Number |
Date |
Country |
Parent |
71675 |
Aug 1979 |
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