WO2014089065A1 - Apparatus for thermoforming polymer composite panels - Google Patents
Apparatus for thermoforming polymer composite panels Download PDFInfo
- Publication number
- WO2014089065A1 WO2014089065A1 PCT/US2013/072855 US2013072855W WO2014089065A1 WO 2014089065 A1 WO2014089065 A1 WO 2014089065A1 US 2013072855 W US2013072855 W US 2013072855W WO 2014089065 A1 WO2014089065 A1 WO 2014089065A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- extruder
- mixed melt
- plastic
- heated
- barrel
- Prior art date
Links
- 239000002131 composite material Substances 0.000 title claims description 12
- 229920000642 polymer Polymers 0.000 title claims description 7
- 238000003856 thermoforming Methods 0.000 title claims 2
- 229920003023 plastic Polymers 0.000 claims abstract description 62
- 239000004033 plastic Substances 0.000 claims abstract description 62
- 238000000465 moulding Methods 0.000 claims abstract description 28
- 239000000203 mixture Substances 0.000 claims description 12
- 238000013329 compounding Methods 0.000 claims description 10
- 239000000835 fiber Substances 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 8
- 239000011324 bead Substances 0.000 claims description 5
- 239000000155 melt Substances 0.000 claims description 5
- 239000011521 glass Substances 0.000 claims description 4
- 230000003014 reinforcing effect Effects 0.000 claims description 4
- KVFIJIWMDBAGDP-UHFFFAOYSA-N ethylpyrazine Chemical compound CCC1=CN=CC=N1 KVFIJIWMDBAGDP-UHFFFAOYSA-N 0.000 claims 1
- 239000000463 material Substances 0.000 description 35
- 238000001125 extrusion Methods 0.000 description 13
- 239000003365 glass fiber Substances 0.000 description 13
- 229920001903 high density polyethylene Polymers 0.000 description 9
- 239000004700 high-density polyethylene Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 9
- 239000000654 additive Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000011152 fibreglass Substances 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000000748 compression moulding Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000012080 ambient air Substances 0.000 description 3
- 239000006229 carbon black Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000012768 molten material Substances 0.000 description 3
- 241000196324 Embryophyta Species 0.000 description 2
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- 229910000831 Steel Inorganic materials 0.000 description 2
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- 230000004888 barrier function Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
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- 238000007906 compression Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 238000003851 corona treatment Methods 0.000 description 2
- 230000013011 mating Effects 0.000 description 2
- 239000008267 milk Substances 0.000 description 2
- 210000004080 milk Anatomy 0.000 description 2
- 235000013336 milk Nutrition 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 229920000307 polymer substrate Polymers 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
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- 241000370685 Arge Species 0.000 description 1
- 239000004604 Blowing Agent Substances 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 1
- 241000238631 Hexapoda Species 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 241001080526 Vertica Species 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- DQEPMTIXHXSFOR-UHFFFAOYSA-N benzo[a]pyrene diol epoxide I Chemical compound C1=C2C(C3OC3C(C3O)O)=C3C=C(C=C3)C2=C2C3=CC=CC2=C1 DQEPMTIXHXSFOR-UHFFFAOYSA-N 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 235000014171 carbonated beverage Nutrition 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
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- 239000006185 dispersion Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001227 electron beam curing Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000011151 fibre-reinforced plastic Substances 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000009408 flooring Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000013072 incoming material Substances 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 235000010446 mineral oil Nutrition 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 238000010137 moulding (plastic) Methods 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000011120 plywood Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920002959 polymer blend Polymers 0.000 description 1
- 239000002952 polymeric resin Substances 0.000 description 1
- 150000003254 radicals Chemical class 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000002990 reinforced plastic Substances 0.000 description 1
- 239000012783 reinforcing fiber Substances 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 235000013580 sausages Nutrition 0.000 description 1
- 238000012163 sequencing technique Methods 0.000 description 1
- 238000009416 shuttering Methods 0.000 description 1
- 229920000260 silastic Polymers 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
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
- 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
- B32B5/22—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 the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
- B32B5/24—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 the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
- B32B5/245—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 the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it being a foam layer
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
- E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
- E04C2/10—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products
- E04C2/20—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products of plastics
- E04C2/22—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products of plastics reinforced
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0011—Combinations of extrusion moulding with other shaping operations combined with compression moulding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
- B29C51/002—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor characterised by the choice of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/26—Scrap or recycled material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
-
- 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
- B32B2250/00—Layers arrangement
- B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
-
- 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
- B32B2255/00—Coating on the layer surface
- B32B2255/02—Coating on the layer surface on fibrous or filamentary layer
-
- 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
- B32B2255/00—Coating on the layer surface
- B32B2255/10—Coating on the layer surface on synthetic resin layer or on natural or synthetic rubber layer
-
- 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
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/10—Inorganic fibres
- B32B2262/101—Glass fibres
-
- 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
- B32B2272/00—Resin or rubber layer comprising scrap, waste or recycling material
-
- 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
- B32B2307/00—Properties of the layers or laminate
- B32B2307/50—Properties of the layers or laminate having particular mechanical properties
- B32B2307/54—Yield strength; Tensile strength
-
- 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
Definitions
- the present invention relates to an apparatus for constructing fiber glass-enhanced polymer composite materials prepared from recycled plasties and use of the apparatus in the construction of these material s.
- Plastics are ubiquitous and play important roles in industries as well as in people's daily life. Recycled plastic materials provide an inexpensive source of plastics. Proper .recycling of plastic wastes and reprocessing them into useful materials or articles can not only protect environments hut may also create huge economic values. However, recycled plasties are often difficult to reformulate into useable products, especially products with consistent mechanical properties.
- Recycled plastics are typically obtained by curbside collection, which itself presents problems as to quality and consistency.
- the types of plastic materials that are typically designated for curbside recycling arc unpigraented high density polyethylene (HOPE) and polyethylene terephthaiate (PET), which together constitute about 80% of the collected recycled plastics.
- HOPE high density polyethylene
- PET polyethylene terephthaiate
- plastic milk bottles are made from unpigmeoted HDPE
- PET/HDPE two-piece containers.
- Plastic polymers and plastic composite materials offer a viable alternative to wood and concrete.
- Manufactured plastic composites can exhibit the necessary stiffness strength, resistance to heat expansion and deformation, increased resistance to degradation from moisture and excessive sunlight, and attacks by microorganisms and insects.
- Plastic panels would aiso have a longer expected service life thereby reducing the labor and material costs associated with replacement
- the present invention provides a new apparatus for processing recycled plasties and converting them to useful materials for consumer and industrial use by processing them into panels and other useful articles by means of extrusion and compression molding.
- a system and apparatus for making a plastic panel, wherein the apparatus combines:
- an extruder with a heated barrel wherein the heated barrel has a feed end opening, a discharge outlet and a least one screw flight therebetween, wherein the screw flight is configured to form a uniform homogenous mixed melt of a optional glass bead or fiber reinforcing component and a polymer component at the operating temperature of the extruder from a polymer mixture delivered thereto through the barrel inlet opening:
- a heated machine press with opposing top and bottom platens configured to receive one of the molding tools therebetween and apply compressi ve force to the top and bottom surfaces to form, the plastic panei in the molding tool:
- At least one heated vessel for receiving and storing a quantity of mixed melt selected to form the plastic panel of predetermined thickness
- the vessel has an inlet pott to receive the mixed melt discharged from the barrel outlet of the extruder; a discharge port configured to deliver the mixed melt from the vessel to the cavity of the molding tool; and a metering device set to deliver the selected quantity of mixed melt from the vessel through the discharge port to the molding tool cavity.
- the apparatus further includes at least one temperature controller set to maintain the extruder barrel, the heated vessel and the machine press at a temperature above the melt flow temperature of said mixed melt
- the extruder is a single screw compounding extruder.
- the extruder is a twin screw extruder a d, more particularly, a twin screw compounding extruder.
- the metering device is a pneumatic piston.
- the apparatus further includes at least one opening in a side all of the forming die to release any excess of mixed, melt delivered to the die.
- FIG. 1 is a side view of a molding tool according to the present invention with a slug of molten plastic deposited therein;
- FIG. 2A illustrates the uni-axtal orientation of an extruded fiber-reinforced plastic sheet
- FIG, 2B illustrates the mulit-axial orientation of an ex truded fi ber-reinforced plastic sheet according to the present invention
- FIG. 3 is a diagrammatic view of a system and apparatus according to the present invention. DETAILED DESCRIPTION OF THE INVENTION
- the present invention relates to an apparatus for manufacturing plastic articles from recycled plasties, typically polyolefms, and optional reinforcing glass beads or fibers, typically glass fibers.
- the present invention relates to an apparatus for processing the recycled plasties and optional reinforcing fibers into rectangular panels and other useful articles having wide application.
- the manufacturing apparatus embodies an extrusion-compression molding process.
- a molten slug of plastic 10 is deposited into an open molding tool 12, which is closed inside a press (not shown), prior to moving into ambient air cooling, individual molding tools are used to produce the composite panels, typically 8' 4 ' sheets, m thicknesses of 4 mm, 8 mm, 12 mm, etc., which allows a flexible mix of thicknesses to be produced, by reordering die moid tools.
- "flat panel” means a piece of material, having considerable extent of surface; usually a rectangular piece of greater length than breadth and distinguished by its thinness; being more than 4 inches (102 mm) in width and not more than 2.5 inches (64 mm) in thickness.
- the sheet product is used in a variety of situations, and in many different sectors. This includes, but is not limited to, construction site hoardings, signage, concrete shuttering, rain cladding, cubicle partitions, pipe boxing, sound barriers ⁇ acoustic barriers etc.), arid potential replacement for internal skin of walls, ceilings & flooring.
- the objective is to replace timber-based products such as plywood, Medium Density Fiberooard (DF) and compact grade laminated in a variety of situations.
- DF Medium Density Fiberooard
- the e trasi on/compression moulding combination is much more tolerant of variations of the Melt Flow index of recycled plastics, (The Melt Flow Index is a standard industry measure of the amount a given plastic material Hows at a standard test temperature). Unlike a virgin grade of plastic, which is manufactured to a tight specification, recycled plastics are aggregated together when collected, and a wider spread of melt flow inde is likely.
- a conventional sheet extrusion plant produces a constant web of molten plastic from an ex truder, that is passed through a series of polished rollers and kept under constant tension while it cools and is cropped to size.
- This process is intolerant of changes within the inch flow index of the material
- the linear sheet extrusion process also imparts a uni-axial orientation of the plastic 32 and reinforcement 34 within the sheet 30, giving it different stiffness across the width vs. tlie length, and the risk of uneven shrinkage through heat reversion while in service.
- the extrusion/eonipression molding process disclosed here is much more tolerant of variations of the Melt Flow Index. This enables the efficient of use recycled plastics from a wider range of sources, without interrupting production, and the introductio of high percentages of glass fiber reinforcement within the product that would be troublesome to produce using sheet, extrusion methods. As shown in FIG. 2B, the orientation of .reinforcing glass fibers 42 within an extrusiowcompression molded sheet 40 is much more varied than that of the extruded sheet. This is desirable and imparts similar properties in both width and length.
- a system and apparatus includes an extruder 50 that runs continuously at a modest output, feeding into accumulator device 52 that can empty hot plastic uickly from outlet port 54 to a cavity 1 8 in mold tool 12.
- the mold tool 12 is then inserted between platens 64 and 66 of press 60, which is a hot platen press that can take molten materials and press them into a sheet.
- the tooling is a vented rectangular aluminum mold tool 12 with top .14 and lower half 16.
- the mold tool can also have a chrome or any other metal finish (not shown) that will, aid mold release.
- the design of the extruder 50 and screw is significant.
- the extruder In addition to creating an even melt of the plastic material, the extruder must disperse and distribute the additives and glass fibres evenly throughout the mix.
- a long single screw compounding extruder is preferred.
- a screw of varying pitch and diameter is more preferred, to create conditions of shear, heat and pressure within the extruder.
- This extruder configuration allows excellent mixing, using simple reliable equipment, primarily through dispersive mixing through high shear mixing stages within the extruder.
- a vented extruder is used to allow volatilcs, such as steam, to be removed frora the plastic melt, even though it is unlikely that wet material will be fed into the extruder.
- a 120/130 mm diameter extruder is used with a mixing screw modified to reduce output from nominal specification to around 400 kgrhr.
- a water chiller is installed to provide a temperature regulated supply of cooling water for the extruder barrel. Larger diameter extruder barrels require water cooling.
- Preferred single screw compounding extruders include a Model Taskmaster 1000 single screw compounding extruders manufactured by audcas le Extrusion Systems, Inc. of Cedar Grove, NJ, disclosed in U.S. Provisional Application No. 61/477,826, filed on April 21 , 201 1 , which is hereby incorporated by reference.
- This application discloses a method of just in time compounding in which extomme-coropounded compositions are directly fed to molding equipment.
- the extruder is a twin screw extruder and, more particularly, a twin screw compounding extruder.
- the hot molten plastic mix is it transferred via disc arge outlet 51 to the accumulator device 52.
- This is a cylindrical steel vessel 56, heated by electrical heater bands 58 and 59, where the molten materia! is stored until it is required, when it is discharged through a port 54 using a pneumatically operated piston 55 into cavity 1 8 of mold tool 12.
- two accumulators are fitted to the production machine (not shown) - this arrangement allows the extruder to run continuously and at a more efficient steady state.
- a die bead (not shown) is provided on the extruder outlet for forming die hot molten plastic mix into pellets or flakes.
- the pellets or flakes are solidified and packaged b conventional means well known in the art of plastic formulation.
- polymer materials from two to four sources are obtained, preferably non -virgin.
- the incoming polymer materials are preferably aggregated together to average out any inconsistencies as much as possible. Materials are blended together in batches of up to two tons.
- the other ke incoming raw material is glass fiber strands or glass beads, which, when used, are compounded into the plastic in the extruder, in one embodiment, a combination of industrial waste fiber and virgin fiber is used. According to one embodiment, silastic is used to pre-coat the glass fiber.
- a coupling agent such as maleic anhydride in combination with a free radical initiator such a cuniene peroxide, is used to graft the siSane coated fibers to polyoleflns to provide a composite material with a desirable combination of stiffness and toughness, attributable to the bond achieved between the fibres and the poiyolefin.
- apparatuses according to the present invention may optionally include a small feeder screw or stuffing hopper (not shown) to deliver longer fiber material accurately into the extruder 50.
- a system and apparatus according to the present invention may also optionally include a hot air dryer (not shown). While none of the materials used are significantly hygroscopic, it is possible that, recycled and washed incoming material has residual moisture which should be removed prior to extrusion.
- a system and apparatus according to the present invention may also optionally include a gravimetric blender 70 installed above the feed end inlet 51 of the extruder 50.
- This device creates a small batch of accurately proportioned material in a chamber over the extruder feed, where it is discharged into a vertica! tube 49.
- the rate of discharge of material into the extruder 50 through the feed end inlet 51 can be adjusted to meet the desired feed rate of t he extruder.
- a small screw feeder (not shown) is positioned immediately above the throat 49 at the feed inlet 51 of the extruder 50 to dispense a small percentage of carbon black powder into the material mix.
- This is a dusty material, so it is preferably positioned here to minimize plant cleaning.
- Other plastic molding additives can be delivered here as well.
- Each accumulator will be configured to store and discharge the correct amount of material for either a 4 mm or 8 mm rectangular sheet, A 12 mm thick sheet will require two accumulators to discharge into the same mold cavity.
- a programmable logic controller (not show) is used to control sequencing of dies and accumulator discharge.
- the programming is capable of being performed by one of ordinary skill i the relevant art.
- the mold tools traverse around conveyor line (not shown) controlled by the logic controller, which allows a variable and flexible product mix by varying the number of 4mm, 8 mm and 12 mm tools on the line at a time.
- Each of the tools can be marked for identification by the control system by conventional means.
- An. infra-red heating station ⁇ not shown) is positioned on the conveyor line in advance of the accumulator to pre-heat the mold tools in advance of the molten material discharge.
- the logic controller will then control the output and duration of the infra-red pre-heater and synchronize the movement of the mold tools into and out of preheating.
- An infra-reel heating system is used because rapid yet controllable increases in temperature are possible because of the high radiant heating efficiency of the heater and the high thermal conductivity of the aluminium mold tooling.
- the mold tool 12 is preferably preheated to an adequate temperature before the molten plastic is applied to allo the plastic material to flow over the entire surface of the tool without sticking to the surface of the tool or changing phase. Typically, this is a temperature between about 100 and about 125 °C.
- a mold release/lubricant may be applied to the aluminium surface of the tool to be contacted by the molten plastic.
- a heavy application of mineral oil may be applied to both tool faces.
- the top half 14 of the tool will pass by the delivery point of the accumulator and move directly to a tool mating station (not shown), where it will be lifted and rotated to await the arrival of the lower half 16 of the tool 12.
- the preheated lower half 16 of the tool 12 will move under the outlet 54 of the accumulator in synchronous movement with the accumulator piston 55 - allowing a metered amount of material to be fed into position withi the mold tool.
- the extruder 50 and accumulator 52 are mounted at right angles to moid tool 12 on a movable trolley (not shown).
- the trolley is pushed parallel to the mold tool during accumulator discharge to ensure an even application of molten material 10 into the cavity 18 of the lower half .16 of the moid tool 12.
- An effective pattern of material distribution from the accumulator into the tool cavity is a dog bone shape, which allows a slight overfilling of the mold. This patters, combined with comer vents 15 on the lower half 16 of the moid tool 12 consistently produce panels of acceptable quality.
- each mold tool 12 is then mated with the top half 14, and moved into a heated press 60 where the molten plastic 10 is squeezed between the top and lower tool halves until the tool is fully closed.
- Platen presses suitable .for use with the present invention have a closing force of at least 90 toss, and preferably at least 150 tons. A closing force of 90 tons is able to consistently compression mold production samples, although more time is needed for the sausage shaped slug of hot plastic to flow and reach the vent ports 15 of the mold tool 12. Additional force and preheating of tooling prior to delivery of molten plastic info the tool and closure will reduce cycle time considerably.
- the mold tool 12 is moved to a cooling conveyor (not shown), where it is cooled using ambient air, fans and water spray (not shown).
- a cooling conveyor not shown
- ambient air, fans and water spray not shown
- this is an accumulating gravity conveyor, so the mold tools will safely wait until the unloading operator is ready.
- vent ports 1 are cleared of molten plastic before die molded sheet cools below 90 C C. If this is not carried out the excess material within the vent ports cools more quickly than the material inside the mould cavity and restricts shrinkage on internal mould areas nearby. This uneven shrinkage exhibits itself as a "stretched" area of the finished sheet which then bows out of plane of the rest of the sheet.
- the mold tool 12 and product within is cooled until the product is rigid enough to be safely removed from the mold tool, the mold tool is opened by an operator using a small overhead crane unit The product is lifted out and placed on a table where the oper tor inspects the product and removes any excess flash with a heated knife.
- quality approved products are placed on input conveyor (not shown) of corona discharge machine (not shown).
- Plasties from the olefin family have traditionally had many virtues, including relatively low cost, but have a low energy surface in their unmodified state, making use of coatings and adhesi ves difficult:.
- flame or corona treatment of the surface can change the characteristics of the plastics surface, creating a higher energy surface, to which coatings, adhesives, paints, foils, and laminating can bond successfully-
- a corona treatment process and/or Electron Beam Curing process (not shown) is optionally installed at the end of the process line to treat ah output sheets.
- the compact grade alternative product is used for, but not limited to, laboratory furniture, lockers, external building cladding and washroom cubicles.
- a gradual rate of cooling is beneficial in establishing a flat molding when moldings are thicker than 2 mm. It is important to keep compressive stresses induced by shrinkage on cooling even throughout the molding. In thicker moldings, such as the 8 mm thick products, it is not beneficial to cool the outer skin of the molding at a rate greater than the rate at which heat is rejected from the inner core of the molding to the outer surface. Furthermore, the presence of a significant amount of glass fiber within the molding reduces greatly the in-mould shrinkage of the moulding. Observations of 25% glass fiber reinforced products indicate shrinkages of 0.3% across the width of the 8 mm sheets and 1% along the length. ' This difference in shrinkage is believed to be related to the general orientation of the fibres - more fibres are aligned across the width of the sheet than along the length.
- the composite may contain further additives.
- the material used to make the composite can contain small amounts of blowing agen to reduce the number and size of voids formed within the material during cooling, the amount of which can be, for example, less than 0.3 wt. %, e.g., about 0,03 wt. %.
- the blowing agent e.g., azidocarhonarnkie, can be mixed in with the resin powder.
- other foamin agents or gases can be directly metered into the extruder.
- Conventional compounding additives can aiso be combined with the polymer(s) prior to extrusion.
- Suitable additives for the composite paneis include pigments, UV resistant agents, colorants (such as carbon black), modifiers, fillers,, particles, eornpattbilizers, and the like.
- the plastic is selected from high density polyethylene (BDPE) and blends of polypropylene (PP) with HOPE; and polystyrene (PS) with FfDPE.
- BDPE high density polyethylene
- PP polypropylene
- PS polystyrene
- the plastic is virgin material.
- FG fiberglass
- d typical micron-sized E Glass
- L ⁇ 4 Mffl ⁇
- Recycled plastics include those containing high-density polyethylene (HOPE) as the main component, for example, milk bottles, car bumpers, etc.
- HOPE high-density polyethylene
- Recycled HDPE Granulate was blown into fabric silos. Recycled HDPE from several sources was then mixed to average out inconsistencies in supplied material. Material was blended with additional glass fiber, carbon black and additives.
- a long single screw extruder (L/d 36:1 circa 120 mm diameter 350 kg output) was used to compound the material blend.
- a screw of varying pitch and diameter was used to create conditions of shear, heat and pressure within the extruder.
- a vented extruder was used to allow volatiles, such as steam, to be removed front the plastic melt.
- a water chiller unit was provided to supply temperature regulated cooling water to the extruder ' barrel.
- This accumulator is a steel cylinder, heated by electrical heater bands, where the molten -materia! was stored until sufficient quantity accumulated to fill a moid tool cavity, when it was then discharged through a port using a pneumatically operated piston.
- the mold tools traversed around, a. conveyor tine.
- the control system pre-set the output and duration of the Infra Red pre-heater and synchronize the mo vement of the tool into preheating.
- the top half of the tool passed by the delivery point of the accumulator and was moved directly to the tool mating station where it was lifted and rotated prior to arri v al of the lower half of the tool.
- the -preheated lower half of the tool moved under the outlet of the accumulator in synchronous movement with the accumulator piston, allowing a metered amount of material to be fed into position within the tool
- each tool was then mated with the top half and moved into a heated press where the molten plastic was squeezed between the top and lower tools halves until the tool is fully closed.
- iiie press Alter a short time under pressure in iiie press, iiie tool was moved to a cooling conveyor where it was cooled using ambient air, fans and water spray.
- the tool and product within was cooled until it was rigid enough to be safely removed from the tool the tool was opened by an operator using a small overhead crane unit. The product was lifted out and placed on a tabic where the operator inspected the product and removed excess flash wit a heated knife.
Abstract
A system and apparatus for making a plastic panel, combining: an extruder with a heated 'barrel having an inlet opening, a discharge outlet and at least one screw flight there between; a plurality of molding tools having top and bottom surfaces and sidewalls extending there between defining a cavity;a machine press with opposing top and bottom platens configured to receive a molding tool there between and apply compressive force to said top and bottom surfaces; and at least one heated vessel for receiving and storing a quantity of mixed melt, wherein the vessel has an inlet port to receive the mixed melt discharged from the barrel outlet of the extruder; a discharge port configured to deliver the mixed melt from the vessel to the cavity of the molding tool; and a metering device set to deliver the selected quantity of the mixed melt from the vessel through the discharge port.
Description
APPARATUS FOR THER OFORMI G POLYMER COMPOSITE PANELS
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of priority 'under 35 U.S.C. 1 9(e) of US Provisional Application Serial no. 61 /733,083, filed on December 04, 2012, and of US Provisional Application Serial no. 61/733,076, filed on December 04, 2012. This application also claims priority to US Patent Application Serial no. 13/826,969, filed March 14, 2.13, and US Patent Application Serial no. 13/803,744, filed March 14, 213. The foregoing disclosures are incorporated by reference in their entireties,
FIELD OF THE INVENTION
The present invention relates to an apparatus for constructing fiber glass-enhanced polymer composite materials prepared from recycled plasties and use of the apparatus in the construction of these material s.
BACKGROUND OF THE INVENTION
Plastics are ubiquitous and play important roles in industries as well as in people's daily life. Recycled plastic materials provide an inexpensive source of plastics. Proper .recycling of plastic wastes and reprocessing them into useful materials or articles can not only protect environments hut may also create huge economic values. However, recycled plasties are often difficult to reformulate into useable products, especially products with consistent mechanical properties.
Recycled plastics are typically obtained by curbside collection, which itself presents problems as to quality and consistency. The types of plastic materials that are typically designated for curbside recycling arc unpigraented high density polyethylene (HOPE) and polyethylene terephthaiate (PET), which together constitute about 80% of the collected recycled plastics. Fortunately, some industries have standardized their plastic package materials. For example, plastic milk bottles are made from unpigmeoted HDPE, while plastic carbonated beverage bottles are made from PET (one-piece containers) or PET/HDPE (two-piece containers). These containers are easily identified and thus are relatively easy to segregate, thereby facilitating the recycling of these two plasties. This is the reason why these two types of plastic are designated for acceptable curbside recycling designated for resin recovery.
In particular, it: has been demonstrated that recycled plastics, in particular polyolefins, such as HDPE, could be recycled aod reprocessed to form useful materials with high economic value, see e.g., Nosker et at, U.S. Pat. Nos. 5,298,214; 5,789,477; 6,191,228; and 7,0.1 1 ,253, which are all incorporated herein by reference. However, new apparatus and methods in processing recycled plasties and turning them into useful materials with wider applications are still being actively pursued.
Plastic polymers and plastic composite materials offer a viable alternative to wood and concrete. Manufactured plastic composites can exhibit the necessary stiffness strength, resistance to heat expansion and deformation, increased resistance to degradation from moisture and excessive sunlight, and attacks by microorganisms and insects. Plastic panels would aiso have a longer expected service life thereby reducing the labor and material costs associated with replacement
However, die cost of raw materials is a disadvantage of plastic polymers and plastic composites. Virgin polymer resins can be quite expensive, thereby often snaking their use economically unfeasible. Additionally, current extrusion/compression molding apparatuses do not adequately accommodate the extrusion of recycled plastics from a wide range of sources with melt indexes that vary widely.
SUMMARY OF THE INVENTION
The present invention provides a new apparatus for processing recycled plasties and converting them to useful materials for consumer and industrial use by processing them into panels and other useful articles by means of extrusion and compression molding.
According to one aspect of the present invention, a system and apparatus is provided for making a plastic panel, wherein the apparatus combines:
an extruder with a heated barrel, wherein the heated barrel has a feed end opening, a discharge outlet and a least one screw flight therebetween, wherein the screw flight is configured to form a uniform homogenous mixed melt of a optional glass bead or fiber reinforcing component and a polymer component at the operating temperature of the extruder from a polymer mixture delivered thereto through the barrel inlet opening:
a plurality of molding tools with top and bottom surfaces and side-walls extending therebetween defining a cavity dimensioned to produce the plastic panel of predetermined thickness;
7
a heated machine press with opposing top and bottom platens configured to receive one of the molding tools therebetween and apply compressi ve force to the top and bottom surfaces to form, the plastic panei in the molding tool: and
at least one heated vessel for receiving and storing a quantity of mixed melt selected to form the plastic panel of predetermined thickness, wherein the vessel has an inlet pott to receive the mixed melt discharged from the barrel outlet of the extruder; a discharge port configured to deliver the mixed melt from the vessel to the cavity of the molding tool; and a metering device set to deliver the selected quantity of mixed melt from the vessel through the discharge port to the molding tool cavity.
According to an embodiment the apparatus further includes at least one temperature controller set to maintain the extruder barrel, the heated vessel and the machine press at a temperature above the melt flow temperature of said mixed melt According to another embodiment, the extruder is a single screw compounding extruder. According to yet another embodiment, the extruder is a twin screw extruder a d, more particularly, a twin screw compounding extruder.
According to one embodiment, the metering device is a pneumatic piston. In another embodiment, the apparatus further includes at least one opening in a side all of the forming die to release any excess of mixed, melt delivered to the die.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a molding tool according to the present invention with a slug of molten plastic deposited therein;
FIG. 2A illustrates the uni-axtal orientation of an extruded fiber-reinforced plastic sheet;
FIG, 2B illustrates the mulit-axial orientation of an ex truded fi ber-reinforced plastic sheet according to the present invention; and
FIG. 3 is a diagrammatic view of a system and apparatus according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an apparatus for manufacturing plastic articles from recycled plasties, typically polyolefms, and optional reinforcing glass beads or fibers, typically glass fibers. In rt cul r;, the present invention relates to an apparatus for processing the recycled plasties and optional reinforcing fibers into rectangular panels and other useful articles having wide application. The manufacturing apparatus embodies an extrusion-compression molding process.
As shown in FIG, 1, in extrusion-compression .molding, a molten slug of plastic 10 is deposited into an open molding tool 12, which is closed inside a press (not shown), prior to moving into ambient air cooling, individual molding tools are used to produce the composite panels, typically 8' 4' sheets, m thicknesses of 4 mm, 8 mm, 12 mm, etc., which allows a flexible mix of thicknesses to be produced, by reordering die moid tools. In one embodiment, "flat panel" means a piece of material, having considerable extent of surface; usually a rectangular piece of greater length than breadth and distinguished by its thinness; being more than 4 inches (102 mm) in width and not more than 2.5 inches (64 mm) in thickness.
The sheet product is used in a variety of situations, and in many different sectors. This includes, but is not limited to, construction site hoardings, signage, concrete shuttering, rain cladding, cubicle partitions, pipe boxing, sound barriers {acoustic barriers etc.), arid potential replacement for internal skin of walls, ceilings & flooring. The objective is to replace timber-based products such as plywood, Medium Density Fiberooard ( DF) and compact grade laminated in a variety of situations.
The e trasi on/compression moulding combination is much more tolerant of variations of the Melt Flow index of recycled plastics, (The Melt Flow Index is a standard industry measure of the amount a given plastic material Hows at a standard test temperature). Unlike a virgin grade of plastic, which is manufactured to a tight specification, recycled plastics are aggregated together when collected, and a wider spread of melt flow inde is likely.
That is, a conventional sheet extrusion plant produces a constant web of molten plastic from an ex truder, that is passed through a series of polished rollers and kept under constant tension while it cools and is cropped to size. This process is intolerant of changes
within the inch flow index of the material As shown in FIG 2 A, the linear sheet extrusion process, also imparts a uni-axial orientation of the plastic 32 and reinforcement 34 within the sheet 30, giving it different stiffness across the width vs. tlie length, and the risk of uneven shrinkage through heat reversion while in service.
The extrusion/eonipression molding process disclosed here is much more tolerant of variations of the Melt Flow Index. This enables the efficient of use recycled plastics from a wider range of sources, without interrupting production, and the introductio of high percentages of glass fiber reinforcement within the product that would be troublesome to produce using sheet, extrusion methods. As shown in FIG. 2B, the orientation of .reinforcing glass fibers 42 within an extrusiowcompression molded sheet 40 is much more varied than that of the extruded sheet. This is desirable and imparts similar properties in both width and length.
As shown in FIG. 3, a system and apparatus according to the present invention includes an extruder 50 that runs continuously at a modest output, feeding into accumulator device 52 that can empty hot plastic uickly from outlet port 54 to a cavity 1 8 in mold tool 12. The mold tool 12 is then inserted between platens 64 and 66 of press 60, which is a hot platen press that can take molten materials and press them into a sheet. According to one embodiment, the tooling is a vented rectangular aluminum mold tool 12 with top .14 and lower half 16. The mold tool can also have a chrome or any other metal finish (not shown) that will, aid mold release.
In order to achieve an even dispersion of fibers and other components within the molten plastic, the design of the extruder 50 and screw is significant. In addition to creating an even melt of the plastic material, the extruder must disperse and distribute the additives and glass fibres evenly throughout the mix.
While essentially any compounding extruder can be adapted for use with the present invention, a long single screw compounding extruder is preferred. A screw of varying pitch and diameter is more preferred, to create conditions of shear, heat and pressure within the extruder. This extruder configuration allows excellent mixing, using simple reliable equipment, primarily through dispersive mixing through high shear mixing stages within the extruder. According to one embodiment, a vented extruder is used to
allow volatilcs, such as steam, to be removed frora the plastic melt, even though it is unlikely that wet material will be fed into the extruder.
In one embodiment, a 120/130 mm diameter extruder is used with a mixing screw modified to reduce output from nominal specification to around 400 kgrhr. In another embodiment, a water chiller is installed to provide a temperature regulated supply of cooling water for the extruder barrel. Larger diameter extruder barrels require water cooling.
Preferred single screw compounding extruders include a Model Taskmaster 1000 single screw compounding extruders manufactured by audcas le Extrusion Systems, Inc. of Cedar Grove, NJ, disclosed in U.S. Provisional Application No. 61/477,826, filed on April 21 , 201 1 , which is hereby incorporated by reference. This application discloses a method of just in time compounding in which extaider-coropounded compositions are directly fed to molding equipment.
in an alternative embodiment, the extruder is a twin screw extruder and, more particularly, a twin screw compounding extruder.
Post extrusion, the hot molten plastic mix is it transferred via disc arge outlet 51 to the accumulator device 52. This is a cylindrical steel vessel 56, heated by electrical heater bands 58 and 59, where the molten materia! is stored until it is required, when it is discharged through a port 54 using a pneumatically operated piston 55 into cavity 1 8 of mold tool 12. In one embodiment, two accumulators are fitted to the production machine (not shown) - this arrangement allows the extruder to run continuously and at a more efficient steady state. in an alternative embodiment, a die bead (not shown) is provided on the extruder outlet for forming die hot molten plastic mix into pellets or flakes. The pellets or flakes are solidified and packaged b conventional means well known in the art of plastic formulation.
To create a material blend as close to a standard set of properties as possible, polymer materials from two to four sources are obtained, preferably non -virgin. The incoming polymer materials are preferably aggregated together to average out any inconsistencies as much as possible. Materials are blended together in batches of up to two tons.
The other ke incoming raw material is glass fiber strands or glass beads, which, when used, are compounded into the plastic in the extruder, in one embodiment, a combination of industrial waste fiber and virgin fiber is used. According to one embodiment, silastic is used to pre-coat the glass fiber. In another embodiment, a coupling agent such as maleic anhydride in combination with a free radical initiator such a cuniene peroxide, is used to graft the siSane coated fibers to polyoleflns to provide a composite material with a desirable combination of stiffness and toughness, attributable to the bond achieved between the fibres and the poiyolefin.
The viscosity of the molten plastic increases significantly with increasing glass fiber content and fiber length. Accordingly, the outlet port 54 of the accumulator 52, shown in FIG. 3, should be dimensioned sufficiently to minimize the time necessary to deli ver the mo! ten plastic into the mold. fibers over 13 mm in length are prone to bridging in the feed inlet of the extnider. Accordingly, apparatuses according to the present invention may optionally include a small feeder screw or stuffing hopper (not shown) to deliver longer fiber material accurately into the extruder 50.
A system and apparatus according to the present invention may also optionally include a hot air dryer (not shown). While none of the materials used are significantly hygroscopic, it is possible that, recycled and washed incoming material has residual moisture which should be removed prior to extrusion.
A system and apparatus according to the present invention may also optionally include a gravimetric blender 70 installed above the feed end inlet 51 of the extruder 50. This device creates a small batch of accurately proportioned material in a chamber over the extruder feed, where it is discharged into a vertica! tube 49. The rate of discharge of material into the extruder 50 through the feed end inlet 51 can be adjusted to meet the desired feed rate of t he extruder.
In one embodiment, a small screw feeder (not shown) is positioned immediately above the throat 49 at the feed inlet 51 of the extruder 50 to dispense a small percentage of carbon black powder into the material mix. This is a dusty material, so it is preferably positioned here to minimize plant cleaning. Other plastic molding additives can be delivered here as well.
Each accumulator will be configured to store and discharge the correct amount of material for either a 4 mm or 8 mm rectangular sheet, A 12 mm thick sheet will require two accumulators to discharge into the same mold cavity.
A programmable logic controller (not show) is used to control sequencing of dies and accumulator discharge. The programming is capable of being performed by one of ordinary skill i the relevant art.
The mold tools traverse around conveyor line (not shown) controlled by the logic controller, which allows a variable and flexible product mix by varying the number of 4mm, 8 mm and 12 mm tools on the line at a time. Each of the tools can be marked for identification by the control system by conventional means.
An. infra-red heating station {not shown) is positioned on the conveyor line in advance of the accumulator to pre-heat the mold tools in advance of the molten material discharge. The logic controller will then control the output and duration of the infra-red pre-heater and synchronize the movement of the mold tools into and out of preheating. An infra-reel heating system is used because rapid yet controllable increases in temperature are possible because of the high radiant heating efficiency of the heater and the high thermal conductivity of the aluminium mold tooling. The mold tool 12 is preferably preheated to an adequate temperature before the molten plastic is applied to allo the plastic material to flow over the entire surface of the tool without sticking to the surface of the tool or changing phase. Typically, this is a temperature between about 100 and about 125 °C.
A mold release/lubricant may be applied to the aluminium surface of the tool to be contacted by the molten plastic. For example, a heavy application of mineral oil may be applied to both tool faces.
After the mold tool 12 has been preheated, the top half 14 of the tool will pass by the delivery point of the accumulator and move directly to a tool mating station (not shown), where it will be lifted and rotated to await the arrival of the lower half 16 of the tool 12. The preheated lower half 16 of the tool 12 will move under the outlet 54 of the accumulator in synchronous movement with the accumulator piston 55 - allowing a metered amount of material to be fed into position withi the mold tool.
In one embodiment, the extruder 50 and accumulator 52 are mounted at right angles to moid tool 12 on a movable trolley (not shown). The trolley is pushed parallel to the mold tool during accumulator discharge to ensure an even application of molten material 10 into the cavity 18 of the lower half .16 of the moid tool 12. An effective pattern of material distribution from the accumulator into the tool cavity is a dog bone shape, which allows a slight overfilling of the mold. This patters, combined with comer vents 15 on the lower half 16 of the moid tool 12 consistently produce panels of acceptable quality.
The lower half 16 of each mold tool 12 is then mated with the top half 14, and moved into a heated press 60 where the molten plastic 10 is squeezed between the top and lower tool halves until the tool is fully closed. Platen presses suitable .for use with the present invention have a closing force of at least 90 toss, and preferably at least 150 tons. A closing force of 90 tons is able to consistently compression mold production samples, although more time is needed for the sausage shaped slug of hot plastic to flow and reach the vent ports 15 of the mold tool 12. Additional force and preheating of tooling prior to delivery of molten plastic info the tool and closure will reduce cycle time considerably.
After a short time under pressure in the press 60, the mold tool 12 is moved to a cooling conveyor (not shown), where it is cooled using ambient air, fans and water spray (not shown). In one embodiment, this is an accumulating gravity conveyor, so the mold tools will safely wait until the unloading operator is ready.
Preferably, the vent ports 1 are cleared of molten plastic before die molded sheet cools below 90 CC. If this is not carried out the excess material within the vent ports cools more quickly than the material inside the mould cavity and restricts shrinkage on internal mould areas nearby. This uneven shrinkage exhibits itself as a "stretched" area of the finished sheet which then bows out of plane of the rest of the sheet.
After the mold tool 12 and product within is cooled until the product is rigid enough to be safely removed from the mold tool, the mold tool is opened by an operator using a small overhead crane unit The product is lifted out and placed on a table where the oper tor inspects the product and removes any excess flash with a heated knife.
In another embodiment quality approved products are placed on input conveyor (not shown) of corona discharge machine (not shown). Plasties from the olefin family have traditionally had many virtues, including relatively low cost, but have a low energy surface
in their unmodified state, making use of coatings and adhesi ves difficult:. However, flame or corona treatment of the surface can change the characteristics of the plastics surface, creating a higher energy surface, to which coatings, adhesives, paints, foils, and laminating can bond successfully- For example, a corona treatment process and/or Electron Beam Curing process (not shown) is optionally installed at the end of the process line to treat ah output sheets. The compact grade alternative product is used for, but not limited to, laboratory furniture, lockers, external building cladding and washroom cubicles.
A gradual rate of cooling is beneficial in establishing a flat molding when moldings are thicker than 2 mm. It is important to keep compressive stresses induced by shrinkage on cooling even throughout the molding. In thicker moldings, such as the 8 mm thick products, it is not beneficial to cool the outer skin of the molding at a rate greater than the rate at which heat is rejected from the inner core of the molding to the outer surface. Furthermore, the presence of a significant amount of glass fiber within the molding reduces greatly the in-mould shrinkage of the moulding. Observations of 25% glass fiber reinforced products indicate shrinkages of 0.3% across the width of the 8 mm sheets and 1% along the length. 'This difference in shrinkage is believed to be related to the general orientation of the fibres - more fibres are aligned across the width of the sheet than along the length.
In addition to the polyolefin and fiber glass components, the composite may contain further additives. For example, the material used to make the composite can contain small amounts of blowing agen to reduce the number and size of voids formed within the material during cooling, the amount of which can be, for example, less than 0.3 wt. %, e.g., about 0,03 wt. %. The blowing agent, e.g., azidocarhonarnkie, can be mixed in with the resin powder. Alternatively, other foamin agents or gases can be directly metered into the extruder. Conventional compounding additives can aiso be combined with the polymer(s) prior to extrusion. Suitable additives for the composite paneis include pigments, UV resistant agents, colorants (such as carbon black), modifiers, fillers,, particles, eornpattbilizers, and the like. In one embodiment that includes glass fibers, they are any length suitable for extrusion, in another embodiment, the plastic is selected from high density polyethylene (BDPE) and blends of polypropylene (PP) with HOPE; and polystyrene (PS) with FfDPE. in one embodiment, the plastic is virgin material.
An exemplar effective Mend, in regard of the above described desired properties, used stlaoe to precoat the glass fibre, along with the FUSABOND™ additive. This combination provides a consistent combination of stiffness and toughness due to the strongest bond being achieved between the fibres and the HDPE plastic.
EXAMPLE
Materials
Two components were used for the experimental mixing study, including fiberglass (FG) and recycled plastics. The FG is typical micron-sized E Glass (d:::20 microns, L ~ 4 Mffl}. Recycled plastics include those containing high-density polyethylene (HOPE) as the main component, for example, milk bottles, car bumpers, etc.
Manufacturing
Product was manufactured according to the following stages. Recycled HDPE Granulate was blown into fabric silos. Recycled HDPE from several sources was then mixed to average out inconsistencies in supplied material. Material was blended with additional glass fiber, carbon black and additives. A long single screw extruder (L/d 36:1 circa 120 mm diameter 350 kg output) was used to compound the material blend. A screw of varying pitch and diameter was used to create conditions of shear, heat and pressure within the extruder. A vented extruder was used to allow volatiles, such as steam, to be removed front the plastic melt. A water chiller unit was provided to supply temperature regulated cooling water to the extruder 'barrel.
Post extrusion, the hot molten plastic/glass fiber mi was stored within an
accumulator device. This accumulator is a steel cylinder, heated by electrical heater bands, where the molten -materia! was stored until sufficient quantity accumulated to fill a moid tool cavity, when it was then discharged through a port using a pneumatically operated piston.
The mold tools traversed around, a. conveyor tine. The control system pre-set the output and duration of the Infra Red pre-heater and synchronize the mo vement of the tool into preheating.
After the tool was preheated, the top half of the tool passed by the delivery point of the accumulator and was moved directly to the tool mating station where it was lifted and rotated prior to arri v al of the lower half of the tool. The -preheated lower half of the tool moved under the outlet of the accumulator in synchronous movement with the
accumulator piston, allowing a metered amount of material to be fed into position within the tool
The lower half of each tool was then mated with the top half and moved into a heated press where the molten plastic was squeezed between the top and lower tools halves until the tool is fully closed. Alter a short time under pressure in iiie press, iiie tool was moved to a cooling conveyor where it was cooled using ambient air, fans and water spray. After the tool and product within was cooled until it was rigid enough to be safely removed from the tool the tool was opened by an operator using a small overhead crane unit. The product was lifted out and placed on a tabic where the operator inspected the product and removed excess flash wit a heated knife.
Quality approved products were then placed on the input conveyor of the Corona Discharge machine.
It will be understood by those of skill hi the art. that numerous and various modifications can be made without departing from the spirit of the present invention. Therefore, it should be clearly understood thai the various embodiments of the present invention described herein are illustrative only arid not intended to limit the scope of the present, invention. Ail references cited herein are incorporated by reference in their entirety. Citation of any patent or non-patent references does not constitute admission of prior art.
Claims
1 , A system and apparatus for making a plastic panel, the apparatus comprising: an extruder comprising a heated barrel, said heated barrel comprising a feed end inlet, a discharge outlet and at least one screw flight therebetween, wherein said screw flight is configured to form a uniform homogenous mixed melt of an optional glass bead or fiber reinforcing component and a polymer component at die operating temperature of said exintder from a polymer and fiber mixture component delivered thereto through said barrel inlet opening;
a plurality of moldin tools comprising top and bottom surfaces and sidewalk extending therebetween defining a cavity dimensioned to produce said plastic pane! at a predetermined thickness ;
a heated machine press with opposing top and bottom platens configured to receive one of said molding tools therebetween and apply compressive force to said top and bottom surfaces; and
at least one heated vessei for recei ving and storing a quantity of said mixed melt selected to form a plastic panel of said predetermined thickness, said vessei comprising an inlet port to receive said mixed melt discharged from said barrel outlet of said extruder; a discharge pott configured to deliver said mixed melt from said vessei to the cavity of said molding tool; and a metering device set to deliver said selected quantify of said mixed melt from said vessei through said discharge port to said molding tool cavity.
2. The system and apparatus of Claim 1 , further comprising at least one temperature controller set to maintain said extruder barrel, said heated vessei and said machine press at a temperature above the melt flow temperature of said mixed melt.
2, The system and apparatus of Claim 1 , wherein said extruder is a single screw compounding extruder.
3, The system, and apparatus of Claim I , wherein said extruder is a t win screw extruder.
4, The system and apparatus of Claim 1 , further comprising at least one vent in a sidewall of said forming die to release any excess of said mixed melt delivered to said die.
5. The system and apparatus of Claim I, farther comprising a thermoforraing press for therraoforraing said plastic composite panel into a finished article.
6. The system and apparatus of claim 5, wherein said thermoforming press is configured to produce a finished article selected from the group consisting of a corrugated panel, an embossed panel a boat hull, an aircraft hull, an automotive component and a reaction vessel.
7. The system and apparatus of claim L wherein a surface of at least one of said molding tool surfaces or a surface of a press platen in contact with said molding tool is configured to emboss a pattern or an image on said panel,
S. The system and apparatus of claim 1 , further comprising means for cooling said piastic panel in said molding tool after said forming die is removed from, said machine press.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2893878A CA2893878A1 (en) | 2012-12-04 | 2013-12-03 | Apparatus for thermoforming polymer composite panels |
Applications Claiming Priority (8)
Application Number | Priority Date | Filing Date | Title |
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US201261733076P | 2012-12-04 | 2012-12-04 | |
US201261733083P | 2012-12-04 | 2012-12-04 | |
US61/733,083 | 2012-12-04 | ||
US61/733,076 | 2012-12-04 | ||
US13/826,969 US9422423B2 (en) | 2012-12-04 | 2013-03-14 | Composite articles compression molded from recycled plastic |
US13/826,969 | 2013-03-14 | ||
US13/803,744 | 2013-03-14 | ||
US13/803,744 US20140154349A1 (en) | 2012-12-04 | 2013-03-14 | Apparatus for thermoforming polymer composite panels |
Publications (1)
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WO2014089065A1 true WO2014089065A1 (en) | 2014-06-12 |
Family
ID=50883934
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2013/072855 WO2014089065A1 (en) | 2012-12-04 | 2013-12-03 | Apparatus for thermoforming polymer composite panels |
PCT/US2013/072851 WO2014089062A1 (en) | 2012-12-04 | 2013-12-03 | Composite articles compression molded from recycled plastic |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/US2013/072851 WO2014089062A1 (en) | 2012-12-04 | 2013-12-03 | Composite articles compression molded from recycled plastic |
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CA (2) | CA2893878A1 (en) |
WO (2) | WO2014089065A1 (en) |
Families Citing this family (1)
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CL2016002617A1 (en) * | 2016-10-14 | 2017-02-24 | Vuelvo Mat Ltda | Process for recycling high density polyethylene (hdpe) materials by means of thermofusion and recycled hdpe products. |
Citations (5)
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US5075051A (en) * | 1988-07-28 | 1991-12-24 | Canon Kabushiki Kaisha | Molding process and apparatus for transferring plural molds to plural stations |
US20020100860A1 (en) * | 1999-09-09 | 2002-08-01 | Wieder Klaus A. | Mold vent and method |
US20020147244A1 (en) * | 2001-03-07 | 2002-10-10 | Kishbaugh Levi A. | Injection-molded crystalline/semicrystalline material |
US20100244297A1 (en) * | 2009-03-26 | 2010-09-30 | Fujitsu Limited | Molding apparatus |
US20110262736A1 (en) * | 2010-04-21 | 2011-10-27 | Kyoraku Co., Ltd. | Skinned panel and method of molding thereof |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5789477A (en) * | 1996-08-30 | 1998-08-04 | Rutgers, The State University | Composite building materials from recyclable waste |
EP2118195B1 (en) * | 2007-02-05 | 2014-06-04 | Dow Global Technologies LLC | A crosslinkable polyethylene composition, method of making the same, and articles made therefrom |
-
2013
- 2013-12-03 WO PCT/US2013/072855 patent/WO2014089065A1/en active Application Filing
- 2013-12-03 CA CA2893878A patent/CA2893878A1/en not_active Abandoned
- 2013-12-03 CA CA2893856A patent/CA2893856A1/en not_active Abandoned
- 2013-12-03 WO PCT/US2013/072851 patent/WO2014089062A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5075051A (en) * | 1988-07-28 | 1991-12-24 | Canon Kabushiki Kaisha | Molding process and apparatus for transferring plural molds to plural stations |
US20020100860A1 (en) * | 1999-09-09 | 2002-08-01 | Wieder Klaus A. | Mold vent and method |
US20020147244A1 (en) * | 2001-03-07 | 2002-10-10 | Kishbaugh Levi A. | Injection-molded crystalline/semicrystalline material |
US20100244297A1 (en) * | 2009-03-26 | 2010-09-30 | Fujitsu Limited | Molding apparatus |
US20110262736A1 (en) * | 2010-04-21 | 2011-10-27 | Kyoraku Co., Ltd. | Skinned panel and method of molding thereof |
Also Published As
Publication number | Publication date |
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WO2014089062A1 (en) | 2014-06-12 |
CA2893856A1 (en) | 2014-06-12 |
CA2893878A1 (en) | 2014-06-12 |
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