Thermoplastic articles and improved processes for making the same

• US 7,897,093 B2
• Filed: 04/17/2007
• Issued: 03/01/2011
• Est. Priority Date: 04/19/2006
• Status: Active Grant

• Current Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Anderson, Stephanie K., Jones, Mary Ann, Koppi, Kurt A.
• Primary Examiner(s): Nguyen; Khanh
• Assistant Examiner(s): Squalls; Margaret
• Application Number:
  US11/736,342
• Publication Number:
  US 20070246862A1
• Time in Patent Office: 1,414 Days
• Field of Search: 525/191, 264/328
• US Class Current: 264/328.8
• CPC Class Codes: B29B 7/42 with screw or helix
• CPC Class Codes: B29B 7/60 for feeding, e.g. end guides for the incoming material B29B7/7615 takes precedence; feeding predetermined amounts for mixing in general B01F35/714
• CPC Class Codes: B29B 7/885 with means for treating, e.g. milling, the charges B29B7/905 takes precedence
• CPC Class Codes: B29B 7/90 Fillers or reinforcements , e.g. fibres
• CPC Class Codes: B29C 45/18 Feeding the material into the injection moulding apparatus , i.e. feeding the non-plastified material into the injection unit
• CPC Class Codes: B29C 45/1816 Feeding auxiliary material, e.g. colouring material
• CPC Class Codes: B29C 45/60 Screws
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/285 Feeding the extrusion material to the extruder
• CPC Class Codes: B29C 48/288 in solid form, e.g. powder or granules
• CPC Class Codes: B29C 48/2886 of fibrous, filamentary or filling materials, e.g. thin fibrous reinforcements or fillers
• CPC Class Codes: B29C 48/362 using static mixing devices
• CPC Class Codes: B29C 48/53 having a varying channel depth, e.g. varying the diameter of the longitudinal screw trunk
• CPC Class Codes: B29C 48/67 having incorporated mixing devices not provided for in groups B29C48/52 - B29C48/66
• CPC Class Codes: B29C 49/00 Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
• CPC Class Codes: B29K 2021/00 Use of unspecified rubbers as moulding material
• CPC Class Codes: B29K 2023/00 Use of polyalkenes or derivatives thereof as moulding material
• CPC Class Codes: B29K 2023/12 PP, i.e. polypropylene
• CPC Class Codes: B29K 2105/0002 monomers or prepolymers
• CPC Class Codes: B29K 2105/0085 Copolymers
• CPC Class Codes: B29K 2105/06 : containing reinforcements, fillers or inserts
• CPC Class Codes: B29K 2105/16 : Fillers
• CPC Class Codes: B29K 2995/004 : Semi-crystalline
• CPC Class Codes: C08L 2205/02 : containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2205/035 : containing four or more polymers in a blend
• CPC Class Codes: C08L 23/0815 : Copolymers of ethene with aliphatic 1-olefins
• CPC Class Codes: C08L 23/10 : Homopolymers or copolymers of propene
• CPC Class Codes: C08L 23/16 : Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: C08L 2310/00 : Masterbatches
• CPC Class Codes: C08L 2666/02 : Organic macromolecular compounds, natural resins, waxes or and bituminous materials

Abstract

The present invention is directed to improved processes for making plastic articles, and articles made therefrom. In a broad aspect, the invention is directed to improved processes and articles made therefrom, that include the steps of providing as separate materials a first material that includes a thermoplastic polyolefin, a second material including an admixture of a particulated filler and a second thermoplastic polyolefin, and a third material that includes an elastomer; applying a shear force to the first, second and third materials, while the materials are at an elevated temperature for blending the materials to form a molten blend; shaping the molten blend and solidifying the molten blend.

Claims

1. A process for manufacturing an injection molded article, comprising the steps of:

feeding to an injection molding machine a first material that includes a polyolefin;

feeding to the injection molding machine a second material including an admixture of a particulated filler and a second polyolefin;

feeding to the injection molding machine a third material that includes an elastomer;

blending the first, second and third materials within the injection molding machine to form a blend; and

injecting the blend into a tool wherein the process is substantially free of a step of compounding together the first, second and third materials prior to the blending step;

wherein resulting articles will include a material that will have a lamellar morphology, a droplet morphology having a rubber domain size of about 0.1 micron to about 5 microns, or a combination thereof;

wherein the injecting step includes passing the blend through a static mixer.

2. The process of claim 1, wherein the injection molding machine includes a hopper located upstream of a screw and barrel assembly, the feeding steps include feeding the first, second and third materials into the hopper, the blending step occurs within the screw and barrel assembly, the screw and barrel assembly has a length to diameter ratio greater than about 15:

1, a back pressure of at least about 100 psi is applied to the first, second and third materials during the blending step, a screw speed of about 25 to 250 rpm is employed during the blending step, the blending step occurs at a temperature of about 180 to about 270°

C., and the injecting step includes passing the blend through a static mixer, wherein the elastomer includes a copolymer of alpha-olefins selected from the group consisting of i) ethylene and propylene, ii) ethylene and 1-butene, iii) ethylene and 1-hexene; and

iv) ethylene and 1-octene, and the first polyolefin includes a polypropylene homopolymer or an impact polypropylene copolymer.

4. The process of claim 1, wherein the injection molding machine includes a hopper located upstream of a screw and barrel assembly, and the feeding steps include feeding the first, second and third materials into the hopper.

5. The process of claim 4, wherein the blending step occurs within the screw and barrel assembly, the screw and barrel assembly has a length to diameter ratio greater than about 15:

1, a back pressure of at least about 100 psi is applied to the first, second and third materials during the blending step, a screw speed of about 25 to 250 rpm is employed during the blending step, the blending step occurs at a temperature of about 180 to about 270°

C.

6. The process of claim 1, wherein the injecting step is part of a multiple operation process selected from blow molding, two stage injection molding, or a combination thereof.

7. The process of claim 2, wherein the injecting step is part of a multiple operation process selected from blow molding, two stage injection molding, or a combination thereof.

8. The process of claim 2, wherein (i) the screw of the injection molding machine includes a plurality of both in-flow channels and out-flow channels;

(ii) the injection molding machine includes a mixing flight that includes at least one undercut for providing dispersive mixing, at least one bypass channel for providing distributive mixing or both;

(iii) the blending includes dispersive mixing and distributive mixing;

or (iv) any combination of (i)-(iii).

9. The process of claim 1, wherein

(i)the polyolefin of the first material is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene, having greater than about 40% crystallinity, or any combination of a polypropylene homopolymer and a polypropylene impact copolymer;

(ii) the particulated filler is a talc;

(iii) the second polyolefin is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10 min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene, having greater than about 40% crystallinity, or a combination of a polypropylene homopolymer and a polypropylene impact copolymer; and

(iv) the elastomer of the third material includes an alpha-olefin comonomer, and has a density less than about 0.9, a melt flow rate of about 0.5 to about 30 g/10 min measured at 190°

C., 2.16 kg, and a glass transition temperature of less than about −

30°

C.

10. The process of claim 2, wherein

(i) the polyolefin of the first material is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10 min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene, having greater than about 40% crystallinity, or any combination of a polypropylene homopolymer and a polypropylene impact copolymer;

(ii) the particulated filler is a talc;

(iii) the second polyolefin is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10 min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene having greater than about 40% crystallinity, or a combination of a polypropylene homopolymer and a polypropylene impact copolymer; and

(iv) the elastomer of the third material includes an alpha-olefin comonomer, and has a density less than about 0.9, a melt flow rate of about 0.5 to about 30 g/10 min measured at 190°

C. 2.16 kg, and a glass transition temperature of less than about −

30°

C.

13. The process of claim 1, wherein a viscosity ratio of about 0.2 to 7 is employed.

14. The process of claim 2, wherein a viscosity ratio of about 0.2 to 7 is employed.

16. The process of claim 1, wherein the first material consists of one or more neat polyolefins and optionally one or more additives selected from the group consisting of nucleators, lubricants, slip agents, and stabilizers;

the second material consists of one or more particulated fillers, one or more neat polyolefins and optionally one or more additives selected from the group consisting of nucleators, lubricants, lip agents, and stabilizers;

the third material consists of one or more elastomers; and

the blend consists of one or more neat polyolefins, one or more elastomers, one or more particulated fillers, and optionally one or more additives selected from the group consisting of nucleators, lubricants, slip agents, stabilizers, colorants, reinforcements, colorants, and flame retardants.

3. A process for manufacturing an injection molded article, comprising the steps of:

feeding to an injection molding machine a first material that includes a polyolefin;

feeding to the injection molding machine a second material including an admixture of a particulated filler and a second polyolefin;

feeding to the injection molding machine a third material that includes an elastomer;

blending the first, second and third materials within the injection molding machine to form a blend; and

injecting the blend into a tool wherein the process is substantially free of a step of compounding together the first, second and third materials prior to the blending step;

wherein resulting articles will include a material that will have (a) a combination of (i) failure in a ductile mode by multi-axial dart impact testing measured using the Instrumented Dart Impact Test of greater than about 90% of samples, at −

40°

C., −

30°

C. or 0°

C.; and

(ii) notched Izod Impact value of at least about 3 ft-lbs/in;

(b) a lamellar morphology, a droplet morphology having a rubber domain size of about 0.1 micron to about 5 microns, or a combination thereof;

or a combination of (a) and (b);

wherein (i) the screw of the injection molding machine includes a plurality of both in-flow channels and out-flow channels;

(ii) the injection molding machine includes a mixing flight that includes at least one undercut for providing dispersive mixing, at least one bypass channel for providing distributive mixing or both;

(iii) the blending includes dispersive mixing and distributive mixing;

or (iv) any combination of (i)-(iii).

11. The process of claim 3, wherein

(i) the polyolefin of the first material is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10 min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene, having greater than about 40% crystallinity, or any combination of a polypropylene homopolymer and a polypropylene impact copolymer;

(ii) the particulated filler is a talc;

(iii) the second polyolefin is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10 min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene, having greater than about 40% crystallinity, or a combination of a polypropylene homopolymer and a polypropylene impact copolymer;

(iv) the elastomer of the third material includes an alpha-olefin comonomer, and has a density less than about 0.9, a melt flow rate of about 0.5 to about 30 g/10 min measured at 190°

C., 2.16 kg, and a glass transition temperature of less than about −

30 C.;

or

(v) any combination of (i)-(iv).

12. The process of claim 3, wherein

(i) the polyolefin of the first material is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10 min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene, having greater than about 40% crystallinity, or any combination of a polypropylene homopolymer and a polypropylene impact copolymer;

(ii) the particulated filler is a talc;

(iii) the second polyolefin is a neat polypropylene homopolymer, a neat polypropylene impact copolymer characterized by a melt flow rate of less than about 70 g/10 min measured at 230°

C., 2.16 kg, and containing greater than about 8 wt % of ethylene, having greater than about 40% crystallinity, or a combination of a polypropylene homopolymer and a polypropylene impact copolymer; and

(iv) the elastomer of the third material includes an alpha-olefin comonomer, and has a density less than about 0.9, a melt flow rate of about 0.5 to about 30 g/10 min measured at 190°

C., 2.16 kg, and a glass transition temperature of less than about −

30°

C.

15. The process of claim 12, wherein a viscosity ratio of about 0.2 to 7 is employed.

17. The process of claim 3, wherein the first material consists of one or more neat polyolefins and optionally one or more additives selected from the group consisting of nucleators, lubricants, slip agents, and stabilizers;

the second material consists of one or more particulated fillers, one or more neat polyolefins and optionally one or more additives selected from the group consisting of nucleators, lubricants, lip agents, and stabilizers;

the third material consists of one or more elastomers; and

the blend consists of one or more neat polyolefins, one or more elastomers, one or more pariculuted fillers, and optionally one or more additives selected from the group consisting of nucleators, lubricants, slip agents, stabilizers, colorants, reinforcements, colorants, and flame retardants.

18. The process of claim 3, wherein the screw of the injection molding machine includes a mixing flight that includes at least one undercut for providing dispersive mixing and at least one bypass channel for providing distributive mixing.

19. The process of claim 3, wherein the elastomer includes a copolymers of alpha-olefins selected from the group consisting of i) ethylene and propylene, ii) ethylene and 1-butene, iii) ethylene and 1-hexene;

and iv) ethylene and 1-octene, and the first polyolefin includes a polypropylene homopolymer or an impact polypropylene copolymer.

20. A process for manufacturing an injection molded article, comprising the steps of:

feeding to an injection molding machine a first material that includes a polyolefin;

feeding to the injection molding machine a second material that includes an elastomer;

blending the first, and second materials within the injection molding machine to form a blend; and

injecting the blend into a tool wherein the process is substantially free of a step of compounding together the first and second materials prior to the blending step;

wherein resulting articles included a material having a lamellar morphology, a droplet morphology having a rubber domain size of about 0.1 micron to about 5 microns, or a combination thereof;

wherein the injecting step includes passing the blend through a static mixer;

wherein the elastomer includes a copolymer of alpha-olefins selected from the group consisting of i) ethylene and propylene, ii) ethylene and 1-butene, iii) ethylene and 1-hexene; and

iv) ethylene and 1-octene, and the first polyolefin includes a polypropylene homopolymer or an impact polypropylene copolymer.