Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/065—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of foam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2398/00—Unspecified macromolecular compounds
  • B32B2398/20—Thermoplastics
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2605/00—Vehicles
  • B32B2605/08—Cars

Definitions

• This invention relates to functionalized polyethylenes.
• the invention relates to polyethylenes grafted with an unsaturated organic compound containing at least one double bond and at least one functional acid group, for example, maleic anhydride, while in another aspect, the invention relates to the high compatibility of these functionalized polyethylenes with various thermoplastic polymers containing a polar group.
• the invention relates to articles molded from blends of functionalized polyethylenes and such polymers that can be painted without a surface pretreatment or a special primer while in another embodiment, the invention relates to laminates of functionalized polyethylenes and certain polyurethane foams that demonstrate near perfect adhesion to one another.
• thermoplastic polyolefins Because of their light weight, durability, low cost and other desirable properties, thermoplastic polyolefins (TPO's) have steadily grown in use as a material of construction for a large array of consumer goods. For example, the automotive industry uses these materials in a variety of interior and exterior parts, while household appliance manufacturers employ TPO's in everything from support structures to decorative facia.
• TPO's While TPO's have many desirable properties, they also have certain undesirable properties not the least of which is their reluctance to accept a paint or decorative print. TPO's are, by definition, hydrocarbon polymers, typically a polyethylene, polypropylene or an ethylene-propylene rubber, and as such, are nonpolar. Most paints are polar, and thus require a surface with some degree of polarity before they can adhere to it with any degree of desirable fastness. This problem has been addressed, with varying degrees of success, in a number of different ways.
• Primers are, typically compositions containing a halogenated polyolefin and an aromatic solvent, for example, a chlorinated polypropylene and toluene. hile primers are generally recognized as effective, they are expensive and their application is an extra step in the finishing of the TPO article.
• Another method of enhancing the paintability of a TPO surface is to subject the surface to a physical or chemical etching, or irradiating the surface with a plasma. While generally effective, these methods are more complex in nature than the application of a primer, and thus more difficult to control in terms of quality and consistency from part to part. In addition, these techniques are generally more expensive than the simple application of a primer.
• Yet another technique, and one that continues to grow in use, is to modify the physical and/or chemical properties of the TPO either by blending it with other thermoplastic polymers, or by incorporating into it one or more polar groups, or both.
• USP 4,946,896 to Mitsuno et al. teaches a paintable TPO comprising 20-80 weight percent polypropylene; 5-38 weight percent of an ethylene copolymer consisting of ethylene, an ester unit of either alkyl acrylate or methacrylate, and an unsaturated dicarboxylic acid anhydride; and 5-70 weight percent ethylene- propylene rubber.
• a paintable thermoplastic composition comprises:
• thermoplastic polymer containing polar groups At least one thermoplastic polymer containing polar groups.
• the polyethylene is a high density polyethylene, and it comprises at least about 80 weight percent of the composition.
• the thermoplastic polymer is preferably a nylon or polyurethane.
• the compositions are molded into various articles, for example, automobile parts, while in another embodiment, the grafted polyethylene (g-PE) is laminated to a polyurethane foam.
• the g-PE is blended with and demonstrates excellent adhesion to other materials, such as wood, metal and latex paints.
• the paintable thermoplastic compositipns of this invention can receive and hold paint without the use of a primer or preparatory surface treatment, as can many of the g-PE/other material blends.
• ethylene polymer or copolymer that can be grafted with an unsaturated organic compound containing at least one double bond and at least one functional acid group can be used in this invention.
• Ethylene polymers and copolymers fall into two broad categories, those prepared with a free radical initiator at high temperature and high pressure, and those prepared with a coordination catalyst at high temperature and relatively low pressure.
• the former are generally known as low density polyethylenes (LDPE) and are characterized by branched chains of polymerized monomer units pendant from the polymer backbone.
• LDPE polymers generally have a density between 0.910 and 0.935 g/cc.
• Ethylene polymers and copolymers prepared by the use of a coordination catalyst, such as a Ziegler or Phillips catalyst, are generally known as linear polymers because of the substantial absence of branch chains of polymerized monomer units pendant from the backbone.
• High density polyethylene (HDPE) generally having a density of 0.941 to 0.965 g/cc, is typically a homopolymer of ethylene, and it contains relatively few side branch chains relative to the various linear copolymers of ethylene and an ⁇ -olefin.
• HDPE is well known, commercially available in various grades, and is useful in this invention.
• Linear copolymers of ethylene and at least one alpha-olefin of 3 to 12 carbon atoms, preferably of 4 to 8 carbon atoms, are also well known, commercially available and useful in this invention.
• the density of a linear ethylene/alpha-olefin copolymer is a function of both the length of the alpha-olefin and the amount of such monomer in the copolymer relative to the amount of ethylene, the greater the length of the alpha-olefin and the greater the amount of alpha-olefin present, the lower the density of the copolymer.
• Linear low density polyethylene is typically a copolymer of ethylene and an alpha- olefin of 3 to 12 carbon atoms, preferably 4 to 8 carbon atoms (for example, 1-butene, 1-octene, etc.), that has sufficient alpha-olefin content to reduce the density of the copolymer to that of LDPE.
• the copolymer contains even more alpha-olefin, the density will drop below about 0.91 g/cc and these copolymers are known as ultra low density polyethylene (ULDPE) or very low density polyethylene (VLDPE) .
• the densities of these linear polymers generally range from 0.87 to 0.91 g/cc.
• HDPE is the preferred polyethylene for use in grafting in this invention.
• the HDPE for grafting has a melt index of about 10-25 g/10 min, and a density of about 0.95 - 0.965 g/cm 3 .
• Any unsaturated organic compound containing at least one double bond and at least one functional acid group that will graft to a polyethylene polymer or copolymer as described above can be used in the practice of this invention.
• the compound to be grafted onto the polymeric chain contains a double bond conjugated with the double bond of an acyl group, and preferably the compound has a moderate tendency to polymerize to yield polymers of relatively high molecular weight and which readily undergo chain transfer reactions.
• Typical of such compounds are the acids and anhydrides, if any, of maleic, fumaric, acrylic, methacrylic, itaconic, crotonic, alpha-methyl crotonic, cinnamic.
• Maleic anhydride is the preferred unsaturated organic compound containing at least one double bond and at least one functional acid group.
• the unsaturated organic compound content of the grafted polymer is at least about 0.01 weight percent, and preferably at least about 0.05 weight percent.
• the maximum amount of unsaturated organic compound content can vary to convenience, but typically it does not exceed about 5 weight percent, preferably it does not exceed about 2 weight percent, and more preferably it does not exceed about 1 weight percent.
• the unsaturated organic compound can be grafted to the polymer by any known technique, such as those taught in USP 3,236,917 which is incorporated herein by reference.
• the polymer is introduced into a two-roll mixer and mixed at a temperature of 60 C until a relatively homogeneous mixture is obtained.
• a free radical initiator such as benzoyl peroxide, is added along with the unsaturated compound and the components are mixed at 30 C until the grafting is completed.
• thermoplastic polymers include copolymers of ethylene and acrylic acid (EAA) , ethylene and carbon monoxide (ECO) , polyamides, epoxies, polyurethanes, polyesters and various polyolefins containing polar groups.
• EAA ethylene and acrylic acid
• ECO ethylene and carbon monoxide
• polyamides polyamides
• epoxies polyurethanes
• polyesters and various polyolefins containing polar groups.
• the molecular weights of these materials can vary widely but for compression molding, typically the thermoplastic polymers used in this embodiment have a melt index (I2, measured according to ASTM D-1238, condition 190 C/2.16 kg) between 0.01 and 3,000, preferably between 0.1 and 300.
• the melt index is typically between 0.05 and 1200, preferably between 0.5 and 100.
• the g-PE comprises at least about 50 weight percent , preferably at least about 70 weight percent and more preferably at least about 80 weight percent, of the g-PE/thermoplastic blend.
• Polyurethanes and polyesters are the preferred thermoplastic polymers.
• the g-PE and the thermoplastic polymer are mixed with one another in any conventional manner that ensures the creation of a relatively homogeneous blend. If the blend is molded into a finished article by extrusion, the g-PE and thermoplastic polymer are typically introduced into the extruder separately and mixed within it prior to extrusion. If the blend is molded by a compression or injection technique, then the two components are first well mixed by any conventional means, for example, roller mill, agitator, etc., and then introduced as a homogeneous mass into the mold.
• the surfaces of the mold or die heads can be constructed of any material, conventionally stainless steel, preferably these surfaces are constructed of or coated with a polyester or polytr.ter film, such as Mylar® (manufactured by the E. I. Du Pont de Nemours & Company) .
• a polyester or polytr.ter film such as Mylar® (manufactured by the E. I. Du Pont de Nemours & Company) .
• Articles shaped under relatively low shear conditions for example, by compression molding, demonstrate better paint adhesion than articles shaped under relatively high shear conditions, for example, injection molding.
• the g-PE is laminated to a polyurethane (PU) foam.
• PU foam has many different uses, and one of particular interest is as an insulation material.
• rigid PU is presently used as an insulation material in refrigerator cabinets, usually laminated to a terpolymer of acrylonitrile-butadiene-styrene (ABS) .
• ABS acrylonitrile-butadiene-styrene
• the traditional blowing agents for rigid PU foam are chlorofluorocarbons which are currently believed to be a threat to the ozone layer. New blowing agents are under development and these include the hydrochlorofluorocarbons, but these attack and dissolve the ABS liner and this in turn causes poor interfacial adhesion between the liner and the PU foam.
• the g-PE's of this invention demonstrate excellent adhesion to PU foams prepared with a hydrochlorofluorocarbon blowing agent. Accordingly, laminates of ABS and PU foams made from the new blowing agents are readily constructed without detriment to the interfacial adhesion between the two by either blending the ABS with the g-PE prior to lamination with the PU foam, by using the g-PE as an adhesion layer between the two or by substituting the g-PE for the ABS entirely.
• the g-PE can also be used as a binder to form melt blends with wood fibers, for example, cedar fibers. These blends differ from polymer impregnated wood, and demonstrate excellent dimensional stability and water-resistant properties. Their appearance is that of wood but the surface is not wetted by water, that is, water beads on the surface. These blends also accept and retain paint well.
• the grafted polyolefin or g-PE is "let-down" or diluted with virgin polyolefin or another g-PE prior to its use as a blend component or adhesive.
• the g-PE has been prepared as described in USP 4,950,541, it is then back-blended in an extruder with virgin polyethylene to a predetermined dilution. Let- down or dilution ratios will vary with the ultimate application of the g- PE, but weight ratios between 1:10 and 10:1 are typical.
• the grafted polyethylene was a high density polyethylene grafted with maleic anhydride (expressed as HDPE.g.MAH) according to the procedure described in USP 4,950,541.
• the grafted polyethylene and thermoplastic polymer were then fed into a Werner and Pfleiderer ZSK-30 twin-screw extruder operated at about 210 C. The blends were made in one pass.
• Injection molded samples were prepared using a 50 ton Negri-Bossi Injection Molder operated with a ,barrel temperature between 200 and 250 C, a barrel pressure of 40 bars, cooling mold temperature of 85 F (29.4 C) , and a residence time in the cooling mold of about 12 seconds. Compression molded samples were prepared using a Drake Press (Model #45-062) operated with a press platen temperature of about 190 C, a press pressure of 27.7 psi (190.85 kP) for five minutes and then 83.1 psi (572.56 kP)for one minute, and a cooling rate of about 15 C per minute. Unless indicated to the contrary, the surfaces of the compression mold and die heads were made of stainless steel. The samples were formed into 6" x 6" x 3/4" plaques.
• Table 1A reports the results of these tests for the samples prepared by injection molding.
• Table IB reports the results of these tests for the samples prepared by compression molding.
• Table IC reports the legend for Tables 1A and IB.
• HDPE High Density Polyethylene
• Molding temperature in injection molding is 100 F (37.8 C) Melting temperature in injection molding is 430 F (221.1 C) Mylar film installed on steel molding surfaces
• Exxelor Exxelor VA 1830 ethylene/propylene copolymer grafted with MAH and sold by Exxon HDG: HDPE grafted with MAH
• HDG.01 HDPE 10062 which was grafted with about 1.5 weight percent MAH; the grafted product had a MI of about lg/10 min
• HDG.02 HDPE 25355 grafted widi about 1.5 weight percent MAH; the grafted product had a MI of about 2.5g/10 min
• HDG.04 EU ⁇ ylene/1-propene copolymer having a MI of about 25 g/10 min and a density of about 0.955 g/cm 3 which was grafted with about 1.5 weight percent MAH; the grafted product had a MI of about 2.5 g/10 min
• HDPE 25355 Ethylene/1-octene copolymer having a MI of about 25 g/10 min and a density of about 0.955 g cm 3
• HDPE 10062 PE homopolymer having a MI of about lOg/10 min and a density of about 0.962 g/cm 3
• Primacor® 1410 is an ethylene/acrylic acid copolymer made by
• P5980 Primacor® 5980 is an ethylene/acrylic acid copolymer made by
• TPU Thermoplastic Polyure ⁇ iane made by The Dow Chemical
• TPU-80A PELLETHANE® 2102-80A
• TPU-90A PELLETHANE® 2102-90A
• C Indicates a comparative example; not an example of the invention
• Molding conditions directly influence the surface properties and thus the paintability of the plaques.
• Compression molding equipment heat the samples from the free surfaces to the bulk.
• Injection molding equipment after melting the pellets, cool the moldings from the free surface to the bulk.
• the pressure of the two moldings are also different as is the shear ratio.
• the shear ratio for injection molding is about 2000-5000/sec.
• Examples 1-6 report acceptable paint adhesion results on plaques made by injection molding. Controls 1-27 report unacceptable paint adhesion results, and most, if not all, of this can be attributed to the method of fabrication (injection molding) . Similar compositions, as shown above, made by compression molding techniques demonstrate acceptable paint adhesion properties.
• Examples 8-42 show that plaques made from a wide variety of compositions demonstrate excellent paint adhesion properties when made by compression molding. These compositions include simple g-PE diluted or let down with LLDPE (Ex. 8-9) or HDPE (Ex. 10), g-PE itself (Ex. 11-12), and blended with various thermoplastic polymers or simply fillers, for example, polyamide (Ex. 16-17), epoxy (Ex. 18-19), nylon (Ex. 26), fiberglass (Ex. 13-14), talc (Ex. 29-30), etc.
• Controls 28-29, 31-33, and 35-42 show the effect of using an ungrafted polyethylene, alone or blended with various thermoplastic polymers or fillers.
• the rigid polyurethane foam was an appliance polyether polyol/PMDI based formulation of The Dow Chemical Company utilizing two different hydrochlorofluorocarbon blowing agents.
• Final in-place foam densities were in the range of 2.1 (33.64 kg/m 3 )to 2.2 lb/ft 3 (35.24 kg/m 3 ) inorder to assure freeze stability of the foam samples.
• These samples were prepared utilizing a Brett mold which is standard industry equipment for determining the flow characteristics of rigid polyurethane foams.
• the polyethylene panels were mounted in the bottom, middle and top of the Brett mold for foaming such that the effects of variations in foam density and texture could be assessed.
• the results of the adhesion tests are reported in Table 2.
• LDPE 723 is a branched PE homopolymer made by The Dow Chemical Company having a MI of about 8 g/10 min and a density of about 0.916 g/cm 3 .

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Paints Or Removers (AREA)
• Laminated Bodies (AREA)

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• 1993
  • 1993-06-04 WO PCT/US1993/005363 patent/WO1993025617A2/en not_active Application Discontinuation
  • 1993-06-04 EP EP93914397A patent/EP0643742A1/de not_active Withdrawn
  • 1993-06-04 CA CA002137283A patent/CA2137283A1/en not_active Abandoned
  • 1993-06-04 JP JP6501616A patent/JPH07507590A/ja active Pending

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