Polyolefinic Materials for Plastic Composites

• US 20080261471A1
• Filed: 10/20/2005
• Published: 10/23/2008
• Est. Priority Date: 10/22/2004
• Status: Abandoned Application

• Current Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Chen, Hongyu, Wevers, Ronald, McLeod, David G., Chum, Wing S.
• Application Number:
  US11/577,394
• Publication Number:
  US 20080261471A1
• Time in Patent Office: Days
• US Class Current: 442/60
• CPC Class Codes: B29C 2043/3602 with means for positioning, fastening or clamping the material to be formed or preforms inside the mould
• CPC Class Codes: B29C 2043/3631 moving in a frame for pressing and stretching; material being subjected to compressing stretching
• CPC Class Codes: B29C 43/36 Moulds for making articles of definite length, i.e. discrete articles
• CPC Class Codes: B29C 51/004 Textile or other fibrous material made from plastics fibres combined with plastic layers B29C51/145; compression moulding of reinforced plastic articles in matched moulds B29C70/46; using pressure difference B29C70/44
• CPC Class Codes: B29C 70/04 comprising reinforcements only, e.g. self-reinforcing plastics
• CPC Class Codes: B29K 2023/0641 MDPE, i.e. medium density polyethylene
• CPC Class Codes: B29K 2023/12 PP, i.e. polypropylene
• CPC Class Codes: B32B 1/00 Layered products having a non-planar shape
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: D03D 15/283 synthetic polymer-based, e.g. polyamide or polyester fibres cellulose-based artificial fibres D03D15/225
• CPC Class Codes: D03D 15/46 Flat yarns, e.g. tapes or films
• CPC Class Codes: D10B 2321/021 polyethylene
• CPC Class Codes: D10B 2321/022 polypropylene
• CPC Class Codes: D10B 2401/041 thermoplastic; thermosetting
• CPC Class Codes: D10B 2505/02 Reinforcing materials; Prepregs
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1303 Paper containing [e.g., paperboard, cardboard, fiberboard, etc.]
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/1359 Three or more layers [continuous layer]
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1393 : Multilayer [continuous layer]
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 : Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24975 : No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/264 : Up to 3 mils
• CPC Class Codes: Y10T 428/31504 : Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31909 : Next to second addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31913 : Monoolefin polymer
• CPC Class Codes: Y10T 442/2008 : Fabric composed of a fiber or strand which is of specific structural definition

Abstract

A reinforced composite article and method for making the same. The article and method employ at least one elongated member as a reinforcement phase. Specific elongated members are multiple layer structures wherein the layers are each polyolefinic (e.g., at least one of the layers may be a propylene-based polymer, such as a propylene-ethylene copolymer, an isotactic polypropylene homopolymer, or a combination thereof). Optionally, at least one of the layers may include a non-migratory process aid or surface modifier agent. An intermediate form including the elongated member may made and processed (for example, with a step of consolidation) to form a composite article.

Claims

1. A method for making a shaped composite article, comprising the steps of:

a) providing at least one elongated member of a first thermoplastic material (A) and a second thermoplastic material (B), wherein the second thermoplastic material (B) comprises an polypropylene homopolymer;

b) stretching the elongated member;

c) processing the elongated member into an intermediate form that includes a plurality of repeating structural units that are generally free to move relative to each other, wherein the form is capable of being processed to form a shaped composite article; and

d) at least partially consolidating the intermediate form;

characterized in that the polypropylene homopolymer is isotactic and has a peak melting temperature greater than 160°

C. and a crystallinity of at least 30%, both as measured by differential scanning calorimetry, the elongated member is a coextruded structure wherein the second thermoplastic material (B) is located within an interior portion of the elongated member, and the at least partially consolidating step includes heating to a temperature to melt at least a portion of the first thermoplastic material (A), and the elongated member further includes a non-migratory process aid or surface modifier agent.

2. The method of claim 1, wherein the polypropylene homopolymer of the second thermoplastic material (B) has a 1% secant flexural modulus of greater than 2000 MPa and an isotactic pentad/triad ratio of greater than 85%.

3. The method of claim 2, wherein the polypropylene homopolymer of the second thermoplastic material has a peak melting temperature of greater than 160°

C. and a crystallinity of at least 70%.

4. The method of claim 3, wherein the polypropylene homopolymer of the second thermoplastic material (B) has a peak melting temperature of greater than 165°

C.

5. The method of claim 1, wherein the second thermoplastic material (B) further comprises a nucleator/clarifier additive in an amount up to about 2500 ppm of the second thermoplastic material (B).

6. The method of claim 1, wherein the step of stretching the elongated member achieves a stretch ratio of at least 10×

.

7. The method of claim 6, wherein the step of stretching the elongated member consists essentially of a single stage for achieving a stretch ratio greater than 15×

.

8. The method of claim 1, wherein the second thermoplastic material (B) further comprises a propylene-ethylene copolymer, present in a minor amount of the second thermoplastic material (B).

9. The method of claim 8, wherein the polypropylene homopolymer comprises at least 70 wt. % of the second thermoplastic material (B) and the propylene-ethylene copolymer comprises 0 to 30 wt. % of the second thermoplastic material, and the second thermoplastic material (B) has an ethylene content of about 3 to 25 wt. %, a melting range of 50 to 135°

C., and a flexural modulus of about 8 to about 325 MPa.

10. The method of claim 1, wherein the non-migratory process aid or surface modifier agent in an amount less than about 10% by weight of the material of the elongated member.

11. The method of claim 10, wherein the non-migratory process aid or surface modifier agent includes an agent selected from silicones, polyolefins, halogenated polymers, or any combination thereof.

12. The method of claim 11, wherein the agent comprises a high molecular weight silicone.

13. The method of claim 12, wherein the agent comprises an alkyl siloxane.

14. The method of claim 13, wherein the agent comprises dimethylsiloxane.

15. The method of claim 1, wherein at least one of the first thermoplastic material (A) or the second thermoplastic material (B) includes another polymer, a filler, an anti-fibrillation agent, a nucleation agent, a mold release agent, a flame retardant, an electrically conductive agent, an anti-static agent, a pigment, carbon black, an antioxidant, an impact modifier, a stabilizer, or any combination.

16. The method of claim 1, further comprising a step of shaping and at least partially consolidating the intermediate form.

17. The method of claim 1, wherein the step of at least partially consolidating the intermediate form includes heating the intermediate form and clamping it in a manner such that while a force is applied for deforming the intermediate form, the intermediate form is free to move within a predetermined limit.

18. The method of claim 1, further comprising the steps of placing the consolidated and shaped intermediate form into a cavity of a tool;

introducing a third thermoplastic material into the tool cavity; and

ejecting from the tool cavity a reinforced composite article that includes the consolidated intermediate form and the third thermoplastic material.

19. The method of claim 18, wherein the third thermoplastic material is introduced into the tool cavity in a molten state.

20. The method of claim 19, wherein the third thermoplastic material is a polyolefin.

21-41. -41. (canceled)