Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-06-20
2004-06-22
Nutter, Nathan M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S445000, C524S492000, C524S493000
Reexamination Certificate
active
06753373
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to novel polyolefin compositions particularly free of elastomers (plasticizers) comprising a polyolefin, polybutene-1, exfoliated nanocomposites and a coupling agent which links the components together. In particular, the present invention relates to polyolefin compositions comprising polypropylene, polybutene-1 an exfoliated nanocomposite clay and the coupling agent. The polyolefin compositions are used with color pigments to produce molded products with a surface which has an appearance of clear-coated paint film.
(2) Description of Related Art
Crystalline polypropylene polymers are well known in the prior art. Isotactic, syndiotactic and atactic forms are described in U.S. Pat. No. 6,300,419 to Sehanobish et al. It can be a homopolymer or a copolymer with another olefinic polymer.
Crystalline polybutene-1 and blends with polypropylene are described in U.S. Pat. Nos. 4,727,112 and 4,727,113 to Kohyama et al; U.S. Pat. No. 4,886,849 to Hwo et al. These blends have good physical properties.
The use of intercalated and exfoliated layered nanocomposites in polymers to increase strength and heat resistance is well known to those skilled in the art. Illustrative are U.S. Pat. No. 4,889,885 to Usuki et al, U.S. Pat. Nos. 5,993,769, 6,261,640, 5,866,645 to Pinnavaia et al, U.S. Pat. No. 6,242,500 to Lan et al, U.S. Pat. Nos. 6,228,903, 6,057,396, 6,287,634, 5,698,624, 5,578,672, 5,552,469 to Beall et al, U.S. Pat. No. 6,271,298 to Powell et al and U.S. Pat. Nos. 6,121,361, 5,973,053, 6,103,817, and 6,126,734 to Usuki et al. U.S. Pat. No. 6,365,661 to Fischer et al, U.S. Pat. No. 5,962,553 to Ellsworth, U.S. Pat. No. 5,952,095 to Beall et al, U.S. Pat. No. 5,952,093 to Nichols, U.S. Pat. No. 5,747,560 to Christian. All of these patents are incorporated by reference.
U.S. Pat. No. 6,017,989 to Malm et al describes polyolefins modified by an elastomer (plasticizer) which with pigments are used in automotive molded products. The combination in an unpigmented polymer has a haze level of less than 50% as measured by ASTM D-1003-95. Special effects pigments, whether metallic or pearlescent, are described as being particularly suitable for these polyolefin compositions. The problem is twofold: first, the compositions lose strength because of the elastomer and second, the elastomer contributes to a softer surface, which is thus more easily scratchable. It has been thought that the elastomer was essential to make the part non-brittle at temperatures ranging down to −40° C.
OBJECTS
It is therefore an object of the present invention to provide polyolefin compositions which have a very low haze level, which are non-brittle at low temperatures, without the use of an elastomer, and which have significant strength. It is further an object of the present invention to provide polyolefin compositions which are economical to prepare and which are easily thermoformable. These and other objects will become increasingly apparent by reference to the following description.
SUMMARY OF THE INVENTION
The present invention relates to a thermoplastic composition substantially free of elastomers which comprises in admixture:
(a) a crystalline polybutene-1 in an amount between about 0.1 and 20% by weight;
(b) a crystalline polyolefin other than the polybutene-1 having haze of less than about 10% and a luminous transmittance of at least about 80% as measured by ASTM D1003 95;
(c) an exfoliated layered inorganic nanocomposite derived from a precursor nanocomposite with nanolayers and galleries between the nanolayers in an amount between about 0.1 and 5% by weight, wherein the nanocomposite has been exfoliated by (a), (b) or a mixture of (a) and (b);
(d) a coupling agent which couples (a), (b) and (c) together in an amount up to about 10% by weight, wherein the composition when molded without pigments has the haze and the luminous transmittance of (b). Preferably the polyolefin is polypropylene. Preferably the composition contains a color pigment. Preferably the composition is as a formed molded product. Preferably the composition is as a body part for a vehicle. Most preferably the composition is as a body part for a vehicle which duplicates a paint color of the vehicle. Preferably the precursor nanocomposite contains an exfoliating agent which is an organic onium ion for exfoliation by (a) and (b). Preferably the precursor nanocomposite contains an exfoliating agent which links the exfoliated nanocomposite to (a) and (b). Preferably the nanocomposite has a particle size of between about 1 and 100 microns. Preferably the composition as pellets formable into a molded product. Preferably the precursor nanocomposite is a 2:1 layered silicate with a particle size between about 1 and 100 nanometers and contains an organic quaternary ammonium ion between the layers.
The present invention also relates to a method for the preparation of a molded part which comprises:
(a) providing a thermoplastic composition substantially free of elastomers which comprises in a mixture: a crystalline polybutene-1 in an amount between about 0.1 and 20% by weight;
a crystalline polyolefin other than the polybutene-1 having haze of less than about 10% and a transmission of at least about 80%;
an exfoliated layered inorganic nanocomposite derived from a precursor nanocomposite with nanolayers and galleries between the nanolayers in an amount between about 0.1 and 5% by weight, wherein the nanocomposite has been exfoliated by (a), (b) or a mixture of (a) and (b);
a coupling agent which couples (a), (b) and (c) together in an amount up to about 10% by weight, wherein the composition when molded without pigments has the haze and the luminous transmittance of (b); and
(b) forming the molded part so that the part without color pigments has a haze of less than 10% and a luminous transmittance of at least about 80%. Preferably the composition contains a color pigment. Preferably the composition in step (a) has been mixed in a compounding extruder and then injection molded in a screw injection molding machine as a molded product. Most preferably the composition in step (a) is mixed in the extruder without the color pigment, cut into pellets and then injection molded as an article with the pigment.
The present invention further relates to a recycled polyolefin composition which comprises: a particulate comprising a ground molded product of the thermoplastic composition as previously described.
The present invention also relates to a method of recycling a polyolefin composition which comprises:
(a) providing a first molded product of a thermoplastic composition as previously described;
(b) reducing the molded product to a particulate; and
(c) molding the particulate into a second molded product.
As used herein the phrase “substantially free” in relation to the elastomer means usually less than one percent (1%) of the total weight of the composition. The amount of any elastomer used cannot reduce the scratch resistance of the resulting molded product. As used in the present invention the term “polyolefin composition” or “thermoplastic polyolefin composition” means a mixture of the components in the form of pellets which are non-pigmented, pigmented pellets, unpigmented molded products and pigmented molded products.
The term “molded product” refers to a part which has been subjected to heat and pressure to form an article of manufacture with a distinctive shape.
The polyolefin compositions of the present invention are free of elastomers (plasticizers) which tend to make the molded products more scratch resistant. Surprisingly the molded products have very good low temperature properties in absence of the elastomers (plasticizers). The molded products are flexible and strong. The molded products appear as if they were covered with a conventional paint which had been clear coated in the conventional manner and thus are color matched to such finishes, such as on automobiles. The products are useful in setting where a decorative finish is required.
The polyolefin compos
McLeod Ian C.
Nutter Nathan M.
LandOfFree
Polyolefin compositions and method of use thereof in molded... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polyolefin compositions and method of use thereof in molded..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polyolefin compositions and method of use thereof in molded... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3316416