US20150197595A1 - Low free mdi prepolymers for rotational casting - Google Patents
Low free mdi prepolymers for rotational casting Download PDFInfo
- Publication number
- US20150197595A1 US20150197595A1 US14/635,869 US201514635869A US2015197595A1 US 20150197595 A1 US20150197595 A1 US 20150197595A1 US 201514635869 A US201514635869 A US 201514635869A US 2015197595 A1 US2015197595 A1 US 2015197595A1
- Authority
- US
- United States
- Prior art keywords
- diamine
- glycol
- curative
- isocyanate
- polyol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
- C09D175/04—Polyurethanes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/002—Processes for applying liquids or other fluent materials the substrate being rotated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
- B05D7/26—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials synthetic lacquers or varnishes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3203—Polyhydroxy compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/48—Polyethers
- C08G18/4854—Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
- C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/34—Silicon-containing compounds
- C08K3/346—Clay
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/34—Silicon-containing compounds
- C08K3/36—Silica
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/04—Thixotropic paints
Definitions
- the present invention relates generally to the preparation of polyurethane elastomer articles and coatings by rotational casting methods, and to a polyurethane prepolymer composition for use therein comprising 4,4′-diisocyanato diphenylmethane (MDI) capped polyurethane prepolymers containing reduced levels of unreacted diphenylmethane diisocyanate (MDI) monomer, i.e., less than 1.0% by weight based on the weight of the prepolymer.
- MDI 4,4′-diisocyanato diphenylmethane
- Rotational casting techniques have been employed for coating polyurethane elastomer compositions onto rigid substrates.
- the rotational casting method requires shorter production time, there is no need for a mold to hold and composition while it cures, and loss of materials by, e.g., overspraying generally occurs is avoided.
- Rotational casting reduces the number of steps involved in roll coating. However, if the polyurethane reaction mixture gels too slowly, the polyurethane coating will drip off the roll. If the polyurethane reaction mixture is formulated to gel quicker, the polyurethane can gel in the head of the mixer or ridges can develop on the outer surface of the roll requiring machine finishing of the polyurethane coating on the surface of the roll.
- These polyurethane coating compositions have found wide commercial use on rigid substrates, e.g., metals, plastics and composites, in areas such as, for example, paper and steel mill rolls, industrial rolls and graphic art printing rolls.
- U.S. Pat. No. 6,747,117 discloses a composition useful for rotationally casting cylindrical parts comprising an isocyanate-terminated polyurethane prepolymer and a curative agent comprising a polyaspartic ester, typically as part of a co-curative system along with compounds selected from aromatic diamines and diols.
- U.S. Pat. No. 5,601,881 discloses the use of sheet die to allow even thicker coatings to be applied.
- the die is disposed parallel to the axis of rotation of the body at an angle alpha, whereby the rate of reaction of the reaction mixture and the relative movement are synchronized with the circumferential speed of the rotating body in such a way that the successive convolutions overlay in the form of scales and connect together seamlessly.
- a sheet die that produces a film of material with length to width ratio of 10 to 300, has difficulty maintaining even flow rate across the outlet. Differences in flow can come from edge effects, because the edges of the die have more resistance to flow, or from channeling of flow in various areas. Channeling can come from partial plugging, or viscosity increase in one area of the die, resulting in the lower viscosity, fresher material taking the path of least resistance around this area. As a result, flow becomes less even and production must eventually be stopped to clean the die. This can be a serious problem, for example, when producing large rolls where the highest quality is demanded, such as in paper mill rolls. Also, starting and stopping the roll covering operation can result in a noticeable defect in the surface of the roll at the point that production was stopped, further resulting in the roll covering being scrapped.
- US Pat Pub 2004/0091617 discloses a rotational casting method and device for producing thicker layers, but with wider processing windows, allowing for longer runs, lower scrap rates, and higher quality articles.
- the method comprises: (a) rotating the substrate about an axis at a selected rotational speed, (b) applying a polymeric reaction mixture to a surface of the rotating substrate by ejecting the polymeric reaction mixture through a die at a selected flow rate, said die dividing an inlet stream of the polymeric reaction mixture into plural outlet streams, the outlet streams being applied to the substrate and the outlet streams being spaced apart from each other such that the outlet streams flow together seamlessly after application to the substrate, (c) effecting relative linear movement between the rotating substrate and the die in a direction parallel to the axis of rotation at a selected relative linear speed, and, (d) synchronizing the reaction mixture flow rate, the relative linear speed and the rotational speed in such a way that successive convolutions of the outlet streams of the polymeric reaction mixture overlap and meld together seamlessly.
- polyurethane reaction mixtures i.e., compositions comprising polyurethane prepolymers and curing agents, that can expand the palette of polyurethane resins available for deposition by rotational casting.
- Prepolymer compositions useful in rotational casting systems, which employ a prepolymer formed from a select polyol and an organic diisocyanate monomer such as 4,4′-diisocyanato diphenylmethane (MDI), and a curing agent formulated with thixotropic reagents to control the rhological properties of the system as it is applied are known.
- MDI prepolymers contain unreacted free MDI, which is a health hazard when present in the environment at certain levels.
- Some commercial rotational casting grades of prepolymer contain over 10% free MDI.
- US Pat Pub 2009/0076239 discloses MDI prepolymers with extremely low levels of MDI, e.g., less than 1% by weight.
- compositions comprising MDI prepolymers with low free MDI content and curatives of known rotational casting formulations not only improve the industrial hygiene associated with rotational casting, but also surprisingly provide polyurethane resins and products with improved mechanical properties.
- a polyurethane prepolymer composition well suited for use in rotational casting methods, comprising:
- the curative comprises i) a polyol; ii) an aromatic diamine; iii) a thixotropic aliphatic amine, and iv) a thixotropic colloidal additive.
- the prepolymer comprises less than 0.7%, less than 0.5% or less than 0.3% by weight of free MDI monomer, based on the total weight of the prepolymer.
- the invention also provides a method whereby an article is formed by a process that comprises the rotational casting of the inventive composition. Essentially any rotational casting method can be used.
- polyurethane resin composition prepared from the prepolymer composition and articles comprising the polyurethane resin.
- the amount of free MDI in the overall composition would still be limited relative to the amount of prepolymer present, e.g., the amount of free MDI present in the overall composition does not exceed 1%, 0.7%, 0.5% or 3% by weight based on the total amount of prepolymer present in the composition.
- One embodiment of the invention comprises a) the prepolymer above and b) a curative comprising i) a polyol; ii) an aromatic diamine; iii) a thixotropic aliphatic amine; and iv) a thixotropic colloidal additive.
- the curative may comprise a polyaspartic ester, often as part of a mixture comprising e.g., a co-curative selected from the group consisting aromatic diamines and diols and optionally thixotropic agents.
- a material is “thixotropic” if its addition to the polyurethane composition results in a composition whose viscosity lowers under shear and whose viscosity rises (thickens) in the absence of shear.
- Polyols useful in the preparation of the isocyanate-terminated polyurethane prepolymer can include high MW polyols, for example, having a number average molecular weight of at least about 250 and can be as high as, e.g., about 10,000, often from about 650 to 3000, and low MW polyols, e.g., 250 or less. Combinations of high MW and low MW polyols may be used.
- high MW polyols include polyalkylene ether polyols having the general formula HO(RO) n H, wherein R is an alkylene radical and n is an integer large enough that the polyether polyol has a number average molecular weight of at least 250.
- polyalkylene ether polyols are well-known and can be prepared by the polymerization of cyclic ethers such as alkylene oxides and glycols, dihydroxyethers, and the like, using methods known in the art.
- High MW polyol also may include polyester polyols, which can be prepared by reacting dibasic acids, e.g., adipic acid, sebacic, phthalic acid and the like, with diols such as ethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol and diethylene glycol, tetramethylene ether glycol, and the like.
- dibasic acids e.g., adipic acid, sebacic, phthalic acid and the like
- diols such as ethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol and diethylene glycol, tetramethylene ether glycol, and the like.
- Some polyester polyols also employ caprolactone and dimerized unsaturated fatty acids in their manufacture, e.g., a polyester polyol obtained by the addition polymerization of e-caprolactone in the presence of an initiator.
- Low MW polyols i.e., polyols with an average molecular weight of less than 250, include aliphatic glycols such as ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and the like. Low MW polyols are most typically used as the minor part of a High MW/Low MW polyol mixture.
- polyols useful in the preparation of the isocyanate-terminated polyurethane prepolymer of this invention include polytetramethylene ether glycols (PTMEG), polypropylene glycols, and dihydroxypolyesters.
- the isocyanate-terminated polyurethane prepolymer a) comprises a polytetramethylene ether glycol (PTMEG).
- the curative b) comprises a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, PTMEG, polypropylene glycol, and a dihydroxypolyester.
- the curative b) comprises an aromatic amine selected from the group consisting of 4,4′-methylene-bis-(3-chloro)aniline (MBCA), 4,4′methylene-bis-(3-chloro-2,6-diethyl)aniline (MCDEA), diethyl toluene diamine (DETDA), tertiary butyl toluene diamine (TBTDA), dimethylthio-toluene diamine, trimethylene glycol di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4′-methylene bis(2-chloroaniline), 2,2′5-trichloro-4,4′-methylene-diamine, naphthalene-1,5-diamine, ortho-phenylene diamine, meta-phenylene diamine, para-phenylene diamine, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,
- the curative b) comprises a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine.
- a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine.
- the curative b) comprises a thixotropic colloidal additive selected from the group consisting of fumed silica, clay, bentonite, and talc.
- an isocyanate-terminated polyurethane prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, which prepolymer comprises a reaction product of PTMEG and MDI, and which prepolymer comprises less than 1.0%, e.g., less than 0.7%, e.g., less than 0.5%, e.g., less than 0.3%, by weight of free MDI monomer, based on the total weight of the prepolymer; and b) a curative comprising, based on the total weight of the curative agent:
- the isocyanate-terminated polyurethane prepolymer comprises a prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, in a mole ratio of organic diisocyanate monomer to polyol ranging from about 1.7:1 to about 4:1; and b) the curative comprises
- the inventive prepolymer composition provides polyurethane resins, in particular, rotationally cast polyurethanes, with physical properties not readily obtainable from other similar prepolymer compositions.
- polyurethane resins in particular, rotationally cast polyurethanes
- the majority of rotational cast polyurethane systems available on the commercial market can produce hardness ranges between 70 and 95 Shore A.
- a “softening additive” such as plasticizers are added.
- the low free MDI prepolymer composition of the invention can be used to prepare a rotationally cast polyurethane layer with a hardness in the range of 40 to 70 Shore A without the use of any “softening additive”. These layers are also shown to have improved tensile properties and exceptional toughness.
- compositions and methods of the invention can be used in the production of any article where rotational casting is employed, e.g., polyurethane covered rolls, wheels, etc.
- Polyurethane resins prepared from conventional rotational casting prepolymer compositions and low free MDI prepolymer compositions of the invention were prepared and physical properties, tensile and abrasion loss, were tested.
- Polymers of different hardnesses were prepared by varying the ratio of the two curatives listed as known in the art.
- the curatives employed comprise PTMEG, DETDA, dimethylthio-toluene diamine, plus thixotropic additives.
- the tensile properties are given in the following table.
- the LF MDI based ribbon flow materials have higher tensile properties in comparison to the conventional RF grades at the equivalent hardness range.
- Abrasion loss was found to be improved at the lower hardnesses for the LFMDI prepolymers with little difference at the high hardness ranges.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Dispersion Chemistry (AREA)
- Materials Engineering (AREA)
- Polyurethanes Or Polyureas (AREA)
- Paints Or Removers (AREA)
- Moulding By Coating Moulds (AREA)
Abstract
Rotational cast polyurethane composition prepared from a prepolymer composition comprising: a) an isocyanate-terminated polyurethane prepolymer; and b) a curative agent comprising i) a polyol; ii) an aromatic diamine; iii) a thixotropic aliphatic amine; and iv) a thixotropic colloidal additive, wherein the prepolymer comprises a product produce by the reaction of a polyol with an organic diisocyanate monomer comprising 4,4′-diisocyanato diphenylmethane (MDI), and which prepolymer comprises less than 1.0% by weight of free MDI monomer, based on the total weight of the prepolymer, exhibits a range of enhanced physical properties compared to those obtained from prepolymers comprising a higher level of free MDI monomer.
Description
- This patent application is a divisional of U.S. patent application Ser. No. 14/107,044, filed Dec. 16, 2013 which application claims benefit under 35 USC 119(e) of U.S. Provisional Application No. 61/758,339, filed Jan. 30, 2013, the disclosures of each are incorporated herein by reference.
- The present invention relates generally to the preparation of polyurethane elastomer articles and coatings by rotational casting methods, and to a polyurethane prepolymer composition for use therein comprising 4,4′-diisocyanato diphenylmethane (MDI) capped polyurethane prepolymers containing reduced levels of unreacted diphenylmethane diisocyanate (MDI) monomer, i.e., less than 1.0% by weight based on the weight of the prepolymer.
- Methods for coating various substrates are known, e.g., conventional casting technique, spray technique, etc. Rotational casting techniques have been employed for coating polyurethane elastomer compositions onto rigid substrates. Several advantages are associated with this method over the other known coating methods, for example, the rotational casting method requires shorter production time, there is no need for a mold to hold and composition while it cures, and loss of materials by, e.g., overspraying generally occurs is avoided.
- Ruprecht et al., “Roll Covering by Rotational Casting with Fast-reacting PUR Systems”, Polyurethanes World Congress 1991 (Sep. 24-26) pp. 478-481, describes rotational casting techniques useful for producing roll coverings using fast-reacting polyurethane elastomer systems. In these systems, the polyurethane reaction mixture is metered through a movable mixing head which travels at constant speed in the axial direction along the rotating roll core a short distance above its surface. The polyurethane reaction mixture solidifies very quickly (in a matter of seconds), to produce a polyurethane coating with a thickness buildup of 4 to 5 mm. Additional layers of the polyurethane reaction mixture are applied until the desired thickness of polyurethane coating is achieved.
- Rotational casting reduces the number of steps involved in roll coating. However, if the polyurethane reaction mixture gels too slowly, the polyurethane coating will drip off the roll. If the polyurethane reaction mixture is formulated to gel quicker, the polyurethane can gel in the head of the mixer or ridges can develop on the outer surface of the roll requiring machine finishing of the polyurethane coating on the surface of the roll.
- U.S. Pat. No. 5,895,806, incorporated herein by reference, discloses a polyurethane prepolymer composition containing dual thixotropic agents and U.S. Pat. No. 5,895,609, also incorporated herein by reference, discloses a rotational casting method for coating a cylindrical object employing the polyurethane prepolymer composition of the '806 patent. Using the composition containing dual thixotropic agents, a thicker coating was achieved per each pass without any dripping or ridging. These polyurethane coating compositions have found wide commercial use on rigid substrates, e.g., metals, plastics and composites, in areas such as, for example, paper and steel mill rolls, industrial rolls and graphic art printing rolls.
- U.S. Pat. No. 6,747,117, incorporated herein by reference, discloses a composition useful for rotationally casting cylindrical parts comprising an isocyanate-terminated polyurethane prepolymer and a curative agent comprising a polyaspartic ester, typically as part of a co-curative system along with compounds selected from aromatic diamines and diols.
- U.S. Pat. No. 5,601,881, incorporated herein by reference, discloses the use of sheet die to allow even thicker coatings to be applied. The die is disposed parallel to the axis of rotation of the body at an angle alpha, whereby the rate of reaction of the reaction mixture and the relative movement are synchronized with the circumferential speed of the rotating body in such a way that the successive convolutions overlay in the form of scales and connect together seamlessly.
- However, problems are associated with the use of a sheet die. For example, a sheet die that produces a film of material with length to width ratio of 10 to 300, has difficulty maintaining even flow rate across the outlet. Differences in flow can come from edge effects, because the edges of the die have more resistance to flow, or from channeling of flow in various areas. Channeling can come from partial plugging, or viscosity increase in one area of the die, resulting in the lower viscosity, fresher material taking the path of least resistance around this area. As a result, flow becomes less even and production must eventually be stopped to clean the die. This can be a serious problem, for example, when producing large rolls where the highest quality is demanded, such as in paper mill rolls. Also, starting and stopping the roll covering operation can result in a noticeable defect in the surface of the roll at the point that production was stopped, further resulting in the roll covering being scrapped.
- US Pat Pub 2004/0091617, incorporated herein by reference, discloses a rotational casting method and device for producing thicker layers, but with wider processing windows, allowing for longer runs, lower scrap rates, and higher quality articles. The method comprises: (a) rotating the substrate about an axis at a selected rotational speed, (b) applying a polymeric reaction mixture to a surface of the rotating substrate by ejecting the polymeric reaction mixture through a die at a selected flow rate, said die dividing an inlet stream of the polymeric reaction mixture into plural outlet streams, the outlet streams being applied to the substrate and the outlet streams being spaced apart from each other such that the outlet streams flow together seamlessly after application to the substrate, (c) effecting relative linear movement between the rotating substrate and the die in a direction parallel to the axis of rotation at a selected relative linear speed, and, (d) synchronizing the reaction mixture flow rate, the relative linear speed and the rotational speed in such a way that successive convolutions of the outlet streams of the polymeric reaction mixture overlap and meld together seamlessly.
- Despite the many rotational casting applications currently in use, the special rheological requirements on the polyurethane reaction mixture metered onto the substrate can place some restriction on the exact resin composition of the final coating, and hence the physical properties thereof. There is therefore a need for polyurethane reaction mixtures, i.e., compositions comprising polyurethane prepolymers and curing agents, that can expand the palette of polyurethane resins available for deposition by rotational casting.
- Prepolymer compositions, useful in rotational casting systems, which employ a prepolymer formed from a select polyol and an organic diisocyanate monomer such as 4,4′-diisocyanato diphenylmethane (MDI), and a curing agent formulated with thixotropic reagents to control the rhological properties of the system as it is applied are known. These MDI prepolymers contain unreacted free MDI, which is a health hazard when present in the environment at certain levels. Some commercial rotational casting grades of prepolymer contain over 10% free MDI. US Pat Pub 2009/0076239 discloses MDI prepolymers with extremely low levels of MDI, e.g., less than 1% by weight.
- It has been found that compositions comprising MDI prepolymers with low free MDI content and curatives of known rotational casting formulations not only improve the industrial hygiene associated with rotational casting, but also surprisingly provide polyurethane resins and products with improved mechanical properties.
- A polyurethane prepolymer composition, well suited for use in rotational casting methods, comprising:
- a) an isocyanate-terminated polyurethane prepolymer;
-
- wherein the isocyanate-terminated polyurethane prepolymer comprises the reaction product of an organic diisocyanate monomer and a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, polytetramethylene ether glycol (PTMEG), polypropylene glycol, and a dihydroxypolyester, the organic diisocyanate monomer comprises 4,4′-diisocyanato diphenylmethane (MDI), and which prepolymer comprises less than 1.0% by weight of free MDI monomer, based on the total weight of the prepolymer,
and
b) a curative comprising i) a polyol; ii) an aromatic diamine; and a thixotropic agent, e.g. a thixotropic aliphatic amine and/or a thixotropic colloidal additive.
- wherein the isocyanate-terminated polyurethane prepolymer comprises the reaction product of an organic diisocyanate monomer and a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, polytetramethylene ether glycol (PTMEG), polypropylene glycol, and a dihydroxypolyester, the organic diisocyanate monomer comprises 4,4′-diisocyanato diphenylmethane (MDI), and which prepolymer comprises less than 1.0% by weight of free MDI monomer, based on the total weight of the prepolymer,
- Typically the curative comprises i) a polyol; ii) an aromatic diamine; iii) a thixotropic aliphatic amine, and iv) a thixotropic colloidal additive.
- In certain particular embodiments the prepolymer comprises less than 0.7%, less than 0.5% or less than 0.3% by weight of free MDI monomer, based on the total weight of the prepolymer.
- Specific diols, amines and thixotropic agents useful in the invention, as well as other common materials useful in the preparation of polyurethanes that may also be included in the above composition are known in the art.
- The invention also provides a method whereby an article is formed by a process that comprises the rotational casting of the inventive composition. Essentially any rotational casting method can be used.
- Also provided is the polyurethane resin composition prepared from the prepolymer composition and articles comprising the polyurethane resin.
- One embodiment of the invention provides a polyurethane prepolymer composition comprising:
- a) an isocyanate-terminated polyurethane prepolymer;
-
- wherein the isocyanate-terminated polyurethane prepolymer comprises a reaction product of an organic diisocyanate monomer and a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, polytetramethylene ether glycol (PTMEG), polypropylene glycol, and dihydroxypolyesters, the organic diisocyanate monomer comprises 4,4′-diisocyanato diphenylmethane (MDI), and which prepolymer comprises less than 1.0%, e.g., less than 0.7%, e.g., less than 0.5%, e.g., less than 0.3%, by weight of free MDI monomer, based on the total weight of the prepolymer,
and
b) a curative comprising i) a polyol; ii) an aromatic diamine; and a thixotropic agent, for example a thixotropic agent comprising a thixotropic aliphatic amine and/or a thixotropic colloidal additive, often the thixotropic agent comprises a thixotropic aliphatic amine and a thixotropic colloidal additive.
- wherein the isocyanate-terminated polyurethane prepolymer comprises a reaction product of an organic diisocyanate monomer and a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, polytetramethylene ether glycol (PTMEG), polypropylene glycol, and dihydroxypolyesters, the organic diisocyanate monomer comprises 4,4′-diisocyanato diphenylmethane (MDI), and which prepolymer comprises less than 1.0%, e.g., less than 0.7%, e.g., less than 0.5%, e.g., less than 0.3%, by weight of free MDI monomer, based on the total weight of the prepolymer,
- It is anticipated of course that even if one were to introduce free MDI to the polyurethane prepolymer composition in a manner that is unrelated to the preparation of prepolymer component a), the amount of free MDI in the overall composition would still be limited relative to the amount of prepolymer present, e.g., the amount of free MDI present in the overall composition does not exceed 1%, 0.7%, 0.5% or 3% by weight based on the total amount of prepolymer present in the composition.
- One embodiment of the invention comprises a) the prepolymer above and b) a curative comprising i) a polyol; ii) an aromatic diamine; iii) a thixotropic aliphatic amine; and iv) a thixotropic colloidal additive.
- In other embodiments the curative may comprise a polyaspartic ester, often as part of a mixture comprising e.g., a co-curative selected from the group consisting aromatic diamines and diols and optionally thixotropic agents.
- For the purposes of this invention, a material is “thixotropic” if its addition to the polyurethane composition results in a composition whose viscosity lowers under shear and whose viscosity rises (thickens) in the absence of shear.
- Polyols useful in the preparation of the isocyanate-terminated polyurethane prepolymer can include high MW polyols, for example, having a number average molecular weight of at least about 250 and can be as high as, e.g., about 10,000, often from about 650 to 3000, and low MW polyols, e.g., 250 or less. Combinations of high MW and low MW polyols may be used.
- For example, high MW polyols include polyalkylene ether polyols having the general formula HO(RO)nH, wherein R is an alkylene radical and n is an integer large enough that the polyether polyol has a number average molecular weight of at least 250. Such polyalkylene ether polyols are well-known and can be prepared by the polymerization of cyclic ethers such as alkylene oxides and glycols, dihydroxyethers, and the like, using methods known in the art.
- High MW polyol also may include polyester polyols, which can be prepared by reacting dibasic acids, e.g., adipic acid, sebacic, phthalic acid and the like, with diols such as ethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol and diethylene glycol, tetramethylene ether glycol, and the like. Some polyester polyols also employ caprolactone and dimerized unsaturated fatty acids in their manufacture, e.g., a polyester polyol obtained by the addition polymerization of e-caprolactone in the presence of an initiator.
- Low MW polyols, i.e., polyols with an average molecular weight of less than 250, include aliphatic glycols such as ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and the like. Low MW polyols are most typically used as the minor part of a High MW/Low MW polyol mixture.
- For example, polyols useful in the preparation of the isocyanate-terminated polyurethane prepolymer of this invention include polytetramethylene ether glycols (PTMEG), polypropylene glycols, and dihydroxypolyesters.
- In a particular embodiment the isocyanate-terminated polyurethane prepolymer a) comprises a polytetramethylene ether glycol (PTMEG).
- In certain embodiments the curative b) comprises a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, PTMEG, polypropylene glycol, and a dihydroxypolyester.
- In certain embodiments the curative b) comprises an aromatic amine selected from the group consisting of 4,4′-methylene-bis-(3-chloro)aniline (MBCA), 4,4′methylene-bis-(3-chloro-2,6-diethyl)aniline (MCDEA), diethyl toluene diamine (DETDA), tertiary butyl toluene diamine (TBTDA), dimethylthio-toluene diamine, trimethylene glycol di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4′-methylene bis(2-chloroaniline), 2,2′5-trichloro-4,4′-methylene-diamine, naphthalene-1,5-diamine, ortho-phenylene diamine, meta-phenylene diamine, para-phenylene diamine, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, and mixtures thereof.
- In certain embodiments the curative b) comprises a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine.
- In certain specific embodiments the curative b) comprises a thixotropic colloidal additive selected from the group consisting of fumed silica, clay, bentonite, and talc.
- One specific embodiment of the invention provides a polyurethane prepolymer composition comprising:
- a) an isocyanate-terminated polyurethane prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, which prepolymer comprises a reaction product of PTMEG and MDI, and which prepolymer comprises less than 1.0%, e.g., less than 0.7%, e.g., less than 0.5%, e.g., less than 0.3%, by weight of free MDI monomer, based on the total weight of the prepolymer;
and
b) a curative comprising, based on the total weight of the curative agent: -
- i) about 10 wt % to about 90 wt % of a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, PTMEG, polypropylene glycol, and a dihydroxypolyester;
- ii) about 10 wt % to about 90 wt % of an aromatic diamine selected from the group consisting of 4,4′-methylene-bis-(3-chloro)aniline (MBCA), 4,4′methylene-bis-(3-chloro-2,6-diethyl)aniline (MCDEA), diethyl toluene diamine (DETDA), tertiary butyl toluene diamine (TBTDA), dimethylthio-toluene diamine, trimethylene glycol di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4′-methylene bis(2-chloroaniline), 2,2′5-trichloro-4,4′-methylene-diamine, naphthalene-1,5-diamine, ortho-phenylene diamine, meta-phenylene diamine, para-phenylene diamine, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, and mixtures thereof;
- iii) about 0.1 wt % to about 1.5 wt % of a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine; and
- iv) about 1.0 wt % to about 10 wt % of a thixotropic colloidal additive selected from the group consisting of fumed silica, clay, bentonite, and talc, wherein the total active hydrogen content of the curative is equal to about 80-115% of the total isocyanate content of the isocyanate-terminated polyurethane prepolymer.
- For example, the composition above wherein
- a) the isocyanate-terminated polyurethane prepolymer comprises a prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, in a mole ratio of organic diisocyanate monomer to polyol ranging from about 1.7:1 to about 4:1; and
b) the curative comprises -
- i) about 30 to about 60 wt % of the polyol;
- ii) about 20 to about 80 wt % of the aromatic diamine;
- iii) about 0.2 to 0.7 wt % of the thixotropic aliphatic amine; and
- iv) about 2 to about 5 wt % of the thixotropic colloidal additive,
wherein the total active hydrogen content of the curative agent is equal to about 90-95% of the total isocyanate content of the isocyanate-terminated polyurethane prepolymer.
- Processes for combining the components of the prepolymer composition of the invention are well known in the art and need not be discussed here.
- The inventive prepolymer composition provides polyurethane resins, in particular, rotationally cast polyurethanes, with physical properties not readily obtainable from other similar prepolymer compositions. For example, the majority of rotational cast polyurethane systems available on the commercial market can produce hardness ranges between 70 and 95 Shore A. In order to produce a rotational cast polyurethane system with a lower hardness, a “softening additive” such as plasticizers are added.
- However, the low free MDI prepolymer composition of the invention can be used to prepare a rotationally cast polyurethane layer with a hardness in the range of 40 to 70 Shore A without the use of any “softening additive”. These layers are also shown to have improved tensile properties and exceptional toughness.
- Various devices are known for preparing rotational cast polyurethanes, the references cited above describe a few examples of known methods and devices, e.g., U.S. Pat. No. 5,601,881 describes single polyurethane outlet systems including e.g., slit die systems, 2004/0091617 describes systems that provide dual polyurethane outlet streams, etc. The prepolymer compositions are well suited for use with any rotation casted method or device. One embodiment of the invention is to the process of preparing a rotationally cast polyurethane from the prepolymer composition of the invention. Another embodiment is to the polyurethane so produced and another embodiment is to an article comprising said polyurethane.
- The compositions and methods of the invention can be used in the production of any article where rotational casting is employed, e.g., polyurethane covered rolls, wheels, etc.
- Polyurethane resins prepared from conventional rotational casting prepolymer compositions and low free MDI prepolymer compositions of the invention were prepared and physical properties, tensile and abrasion loss, were tested. Polymers of different hardnesses were prepared by varying the ratio of the two curatives listed as known in the art. The curatives employed comprise PTMEG, DETDA, dimethylthio-toluene diamine, plus thixotropic additives.
- The tensile properties are given in the following table. The LF MDI based ribbon flow materials have higher tensile properties in comparison to the conventional RF grades at the equivalent hardness range.
-
Stress Strain Hardness Modulus MPa at Break at Break Shore A 50% 100% 200% 300% N/mm2 % 70 Comp 1.62 2.42 3.47 4.98 6.61 350.75 70 INV 1.83 2.70 4.17 7.74 21.25 387.68 75 Comp 2.03 2.84 4.05 5.90 28.14 487.26 75 INV 2.02 3.01 4.56 7.42 41.86 440.08 80 Comp 2.69 3.53 4.94 7.16 40.63 513.33 80 INV 2.62 3.81 5.91 10.66 36.16 394.41 85 Comp 3.33 4.19 5.76 8.33 44.58 521.32 85 INV 3.38 4.75 7.40 14.69 46.01 397.77 90 Comp 4.10 5.30 8.00 14.10 46.30 416.70 90 INV 6.25 8.55 16.37 43.45 45.14 304.70 95 Comp 6.05 7.20 10.26 17.06 45.75 414.75 95 INV 6.80 8.92 16.14 39.76 56.33 345.39 - Abrasion loss was found to be improved at the lower hardnesses for the LFMDI prepolymers with little difference at the high hardness ranges.
-
DIN Abrasion Hardness Loss Shore A Comp INV 70 75 21 75 45 26 80 34 31 85 37 40 90 57 69 95 52 68
Claims (20)
1. A method for producing a polyurethane polymer, the method comprising subjecting to a rotational casting process a polyurethane prepolymer composition comprising:
a) an isocyanate-terminated polyurethane prepolymer;
wherein the isocyanate-terminated polyurethane prepolymer comprises a reaction product of an organic diisocyanate monomer and a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, polytetramethylene ether glycol, polypropylene glycol, and dihydroxypolyesters,
the organic diisocyanate monomer comprises 4,4′-diisocyanato diphenylmethane, and which prepolymer comprises less than 1.0% by weight of free 4,4′-diisocyanato diphenylmethane monomer, based on the total weight of the prepolymer,
and
b) a curative comprising i) a polyol, ii) an aromatic diamine, iii) a thixotropic aliphatic amine, and iv) a thixotropic colloidal additive,
to provide the polyurethane polymer as a rotationally cast polyurethane layer.
2. The method according to claim 1 wherein the isocyanate-terminated polyurethane prepolymer a) comprises polytetramethylene ether glycol.
3. The method according to claim 1 wherein the curative comprises a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, polytetramethylene ether glycol, polypropylene glycol, and a dihydroxypolyester.
4. The method according to claim 1 wherein the curative comprises an aromatic amine selected from the group consisting of 4,4′-methylene-bis-(3-chloro)aniline, 4,4′methylene-bis-(3-chloro-2,6-diethyl)aniline, diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4′-methylene bis(2-chloroaniline), 2,2′5-trichloro-4,4′-methylene-diamine, naphthalene-1,5-diamine, ortho-phenylene diamine, meta-phenylene diamine, para-phenylene diamine, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, and mixtures thereof.
5. The method according to claim 1 herein the curative comprises a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine.
6. The method according to claim 1 wherein the curative comprises a thixotropic colloidal additive selected from the group consisting of fumed silica, clay, bentonite, and talc.
7. The method according to claim 1 wherein the polyurethane prepolymer composition comprises
a) an isocyanate-terminated polyurethane prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, which prepolymer comprises a reaction product of polytetramethylene ether glycol and 4,4′-diisocyanato diphenylmethane;
and
b) a curative comprising, based on the total weight of the curative:
i) about 10 wt % to about 90 wt % of a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, 1,3-butanediol, polytetramethylene ether glycol and polypropylene glycol;
ii) about 10 wt % to about 90 wt % of an aromatic diamine selected from the group consisting of 4,4′-methylene-bis-(3-chloro)aniline, 4,4′methylene-bis-(3-chloro-2,6-diethyl)aniline, diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4′-methylene bis(2-chloroaniline), 2,2′5-trichloro-4,4′-methylene-diamine, naphthalene-1,5-diamine, ortho-phenylene diamine, meta-phenylene diamine, para-phenylene diamine, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, and mixtures thereof;
iii) about 0.1 wt % to about 1.5 wt % of a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine; and
iv) about 1.0 wt % to about 10 wt % of a thixotropic colloidal additive selected from the group consisting of fumed silica, clay, bentonite, and talc,
wherein the total active hydrogen content of the curative agent is equal to about 80-115% of the total isocyanate content of the isocyanate-terminated polyurethane prepolymer.
8. The method according to claim 7 wherein the polyurethane prepolymer composition comprises
a) an isocyanate-terminated polyurethane prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, in a mole ratio of organic diisocyanate monomer to polyol ranging from about 1.7:1 to about 4:1; and
b) a curative agent comprising
i) about 30 to about 60 wt % of the polyol;
ii) about 20 to about 80 wt % of the aromatic diamine;
iii) about 0.2 to 0.7 wt % of the thixotropic aliphatic amine; and
iv) about 2 to about 5 wt % of the thixotropic colloidal additive,
wherein the total active hydrogen content of the curative agent is equal to about 90-95% of the total isocyanate content of the isocyanate-terminated polyurethane prepolymer.
9. A rotationally cast polyurethane layer obtained by a method comprising subjecting to a rotational casting process a polyurethane prepolymer composition comprising:
a) an isocyanate-terminated polyurethane prepolymer;
wherein the isocyanate-terminated polyurethane prepolymer comprises a reaction product of an organic diisocyanate monomer and a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, polytetramethylene ether glycol, polypropylene glycol, and dihydroxypolyesters,
the organic diisocyanate monomer comprises 4,4′-diisocyanato diphenylmethane, and which prepolymer comprises less than 1.0% by weight of free 4,4′-diisocyanato diphenylmethane monomer, based on the total weight of the prepolymer,
and
b) a curative comprising i) a polyol, ii) an aromatic diamine, iii) a thixotropic aliphatic amine, and iv) a thixotropic colloidal additive.
10. The rotationally cast polyurethane layer according to claim 9 wherein the isocyanate-terminated polyurethane prepolymer a) comprises polytetramethylene ether glycol.
11. The rotationally cast polyurethane layer according to claim 9 wherein the curative comprises a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, polytetramethylene ether glycol, polypropylene glycol, and a dihydroxypolyester.
12. The rotationally cast polyurethane layer according to claim 9 wherein the curative comprises an aromatic amine selected from the group consisting of 4,4′-methylene-bis-(3-chloro)aniline, 4,4′methylene-bis-(3-chloro-2,6-diethyl)aniline, diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4′-methylene bis(2-chloroaniline), 2,2′5-trichloro-4,4′-methylene-diamine, naphthalene-1,5-diamine, ortho-phenylene diamine, meta-phenylene diamine, para-phenylene diamine, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, and mixtures thereof.
13. The rotationally cast polyurethane layer according to claim 1 herein the curative comprises a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine.
14. The rotationally cast polyurethane layer according to claim 9 wherein the curative comprises a thixotropic colloidal additive selected from the group consisting of fumed silica, clay, bentonite, and talc.
15. The rotationally cast polyurethane layer according to claim 1 wherein the polyurethane prepolymer composition comprises
a) an isocyanate-terminated polyurethane prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, which prepolymer comprises a reaction product of polytetramethylene ether glycol and 4,4′-diisocyanato diphenylmethane;
and
b) a curative comprising, based on the total weight of the curative:
i) about 10 wt % to about 90 wt % of a polyol selected from the group consisting of ethylene glycol, diethylene glycol, dipropylene glycol, 1,3-butanediol, polytetramethylene ether glycol and polypropylene glycol;
ii) about 10 wt % to about 90 wt % of an aromatic diamine selected from the group consisting of 4,4′-methylene-bis-(3-chloro)aniline, 4,4′methylene-bis-(3-chloro-2,6-diethyl)aniline, diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4′-methylene bis(2-chloroaniline), 2,2′5-trichloro-4,4′-methylene-diamine, naphthalene-1,5-diamine, ortho-phenylene diamine, meta-phenylene diamine, para-phenylene diamine, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, and mixtures thereof;
iii) about 0.1 wt % to about 1.5 wt % of a thixotropic aliphatic amine selected from the group consisting of ethylene diamine, 1,6-hexanediamine, 1,12-dodecane diamine, 1,4-cyclohexane diamine, isophorone diamine, diethylene triamine, triethylene tetramine, amine-terminated polyoxypropylenes, xylene diamine, and piperazine; and
iv) about 1.0 wt % to about 10 wt % of a thixotropic colloidal additive selected from the group consisting of fumed silica, clay, bentonite, and talc,
wherein the total active hydrogen content of the curative agent is equal to about 80-115% of the total isocyanate content of the isocyanate-terminated polyurethane prepolymer.
16. The rotationally cast polyurethane layer according to claim 15 wherein the polyurethane prepolymer composition comprises
a) an isocyanate-terminated polyurethane prepolymer prepared by reacting an organic diisocyanate monomer with a polyol, in a mole ratio of organic diisocyanate monomer to polyol ranging from about 1.7:1 to about 4:1; and
b) a curative agent comprising
i) about 30 to about 60 wt % of the polyol;
ii) about 20 to about 80 wt % of the aromatic diamine;
iii) about 0.2 to 0.7 wt % of the thixotropic aliphatic amine; and
iv) about 2 to about 5 wt % of the thixotropic colloidal additive,
wherein the total active hydrogen content of the curative agent is equal to about 90-95% of the total isocyanate content of the isocyanate-terminated polyurethane prepolymer.
17. The rotationally cast polyurethane layer according to claim 9 having a hardness in the range of 40 to 70 Shore A.
18. The rotationally cast polyurethane layer according to claim 9 having a hardness in the range of 70 to 95 Shore A.
19. The rotationally cast polyurethane layer according to claim 9 having a hardness of 80 Shore A or lower.
20. A roll or wheel comprising a rotationally cast polyurethane layer according to claim 9 .
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/635,869 US20150197595A1 (en) | 2013-01-30 | 2015-03-02 | Low free mdi prepolymers for rotational casting |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201361758339P | 2013-01-30 | 2013-01-30 | |
US14/107,044 US10208227B2 (en) | 2013-01-30 | 2013-12-16 | Low free MDI prepolymers for rotational casting |
US14/635,869 US20150197595A1 (en) | 2013-01-30 | 2015-03-02 | Low free mdi prepolymers for rotational casting |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/107,044 Division US10208227B2 (en) | 2013-01-30 | 2013-12-16 | Low free MDI prepolymers for rotational casting |
Publications (1)
Publication Number | Publication Date |
---|---|
US20150197595A1 true US20150197595A1 (en) | 2015-07-16 |
Family
ID=51223622
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/107,044 Active 2034-08-05 US10208227B2 (en) | 2013-01-30 | 2013-12-16 | Low free MDI prepolymers for rotational casting |
US14/635,869 Abandoned US20150197595A1 (en) | 2013-01-30 | 2015-03-02 | Low free mdi prepolymers for rotational casting |
US15/409,066 Abandoned US20170130095A1 (en) | 2013-01-30 | 2017-01-18 | Low free mdi prepolymers for rotational casting |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/107,044 Active 2034-08-05 US10208227B2 (en) | 2013-01-30 | 2013-12-16 | Low free MDI prepolymers for rotational casting |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/409,066 Abandoned US20170130095A1 (en) | 2013-01-30 | 2017-01-18 | Low free mdi prepolymers for rotational casting |
Country Status (8)
Country | Link |
---|---|
US (3) | US10208227B2 (en) |
EP (1) | EP2951222B1 (en) |
JP (2) | JP2016504473A (en) |
KR (1) | KR20150127027A (en) |
CN (1) | CN104736586A (en) |
BR (1) | BR112015009424A2 (en) |
CA (1) | CA2883987A1 (en) |
WO (1) | WO2014120498A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3320007B1 (en) * | 2015-07-07 | 2019-05-08 | Akzo Nobel Coatings International B.V. | Coating composition for forming releasable and chemical resistant coatings |
IT201700109802A1 (en) | 2017-10-02 | 2019-04-02 | Lanxess Solution Italia S R L | Method and composition for rotational molding of a polyurethane coating layer |
KR102145163B1 (en) * | 2020-05-06 | 2020-08-18 | 에스켐텍(주) | Fast-curing polyurethane resin composition for rotary casting |
EP4347679A1 (en) | 2021-06-03 | 2024-04-10 | Carbon, Inc. | Methods for the rapid production of blocked prepolymers |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5895806A (en) * | 1996-05-06 | 1999-04-20 | Uniroyal Chemical Company, Inc. | Polyurethane composition useful for coating cylindrical parts |
US20030065124A1 (en) * | 1999-11-30 | 2003-04-03 | Rosenberg Ronald O. | High performance polyurethane elastomers from MDI prepolymers with reduced content of free MDI monomer |
US20030232954A1 (en) * | 2002-06-14 | 2003-12-18 | Crompton Corporation | Polyurethane/urea composition for coating cylindrical parts |
US20040091617A1 (en) * | 2002-11-11 | 2004-05-13 | Crompton Corporation | Method and device for applying a thick reactive coating on a body rotating about an axis |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4287307A (en) | 1980-03-05 | 1981-09-01 | Plastics Technology Associates, Inc. | Integral skin microcellular polyester base polyurethane elastomers |
CA2051548C (en) | 1990-09-18 | 1996-04-30 | Hiroshi Ueda | Resin compositions and molded articles |
US5601881A (en) | 1993-07-30 | 1997-02-11 | Bayer Aktiengesellschaft | Method and device for coating a body rotating about an axis |
US5423929A (en) | 1993-10-27 | 1995-06-13 | Allergan, Inc. | Intraocular lenses and methods for producing same |
BR0016485B1 (en) | 1999-12-10 | 2010-08-24 | Method for improving the bubble resistance of a polyurea polymer and molded part of the car body. | |
US6884904B2 (en) | 2001-04-12 | 2005-04-26 | Air Products And Chemicals, Inc. | MDI-based polyurethane prepolymer with low monomeric MDI content |
FR2902364B1 (en) | 2006-06-16 | 2012-04-27 | Commissariat Energie Atomique | METHOD FOR MANUFACTURING A THERMOSETTING POLYMER SEALANT FOR A RESERVOIR CONTAINING A PRESSURIZED FLUID, SUCH AS A COMPOSITE TANK, AND TANK |
CN101842402A (en) | 2007-09-04 | 2010-09-22 | 陶氏环球技术公司 | Reaction injection molded polyurethanes made using high levels of natural oil-based polyols |
US20100151181A1 (en) | 2008-12-12 | 2010-06-17 | Lifeport | Polymeric Composition and Durable Polymeric Panels and Devices Exhibiting Antiballistic Capacity Made Therefrom |
US10052853B2 (en) | 2009-12-09 | 2018-08-21 | Lifeport, Inc. | Durable polymeric panels and devices exhibiting antiballistic capacity made therefrom |
DE102009005017A1 (en) | 2009-01-17 | 2010-07-22 | Bayer Materialscience Ag | Reactive polyurethane compositions |
JP5385772B2 (en) | 2009-12-15 | 2014-01-08 | 住化バイエルウレタン株式会社 | Manufacturing method of outdoor facility pavement, surface finishing material used therefor, and outdoor facility pavement obtained thereby |
-
2013
- 2013-12-16 US US14/107,044 patent/US10208227B2/en active Active
-
2014
- 2014-01-20 CN CN201480002721.4A patent/CN104736586A/en active Pending
- 2014-01-20 KR KR1020157010320A patent/KR20150127027A/en not_active Application Discontinuation
- 2014-01-20 WO PCT/US2014/012187 patent/WO2014120498A1/en active Application Filing
- 2014-01-20 CA CA2883987A patent/CA2883987A1/en not_active Abandoned
- 2014-01-20 BR BR112015009424A patent/BR112015009424A2/en not_active IP Right Cessation
- 2014-01-20 EP EP14703218.9A patent/EP2951222B1/en active Active
- 2014-01-20 JP JP2015553875A patent/JP2016504473A/en active Pending
-
2015
- 2015-03-02 US US14/635,869 patent/US20150197595A1/en not_active Abandoned
-
2017
- 2017-01-18 US US15/409,066 patent/US20170130095A1/en not_active Abandoned
- 2017-04-25 JP JP2017086177A patent/JP2017197735A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5895806A (en) * | 1996-05-06 | 1999-04-20 | Uniroyal Chemical Company, Inc. | Polyurethane composition useful for coating cylindrical parts |
US20030065124A1 (en) * | 1999-11-30 | 2003-04-03 | Rosenberg Ronald O. | High performance polyurethane elastomers from MDI prepolymers with reduced content of free MDI monomer |
US20090076239A1 (en) * | 1999-11-30 | 2009-03-19 | Rui Xie | High performance polyurethane elastomers from mdi prepolymers with reduced content of free mdi monomer |
US20030232954A1 (en) * | 2002-06-14 | 2003-12-18 | Crompton Corporation | Polyurethane/urea composition for coating cylindrical parts |
US20040091617A1 (en) * | 2002-11-11 | 2004-05-13 | Crompton Corporation | Method and device for applying a thick reactive coating on a body rotating about an axis |
Non-Patent Citations (2)
Title |
---|
Bhowmick, et al. "Rubber Products Manufacturing Technology" pg 735, February 15, 1994. * |
Ruprecht et al. "Roll Covering by Rotation Casting with Fast Reacting PUR Systems", pg 478-481, Polyurethanes World Congress 1991, September 24-26, 1991. * |
Also Published As
Publication number | Publication date |
---|---|
JP2016504473A (en) | 2016-02-12 |
BR112015009424A2 (en) | 2017-07-04 |
WO2014120498A1 (en) | 2014-08-07 |
EP2951222B1 (en) | 2016-09-21 |
CA2883987A1 (en) | 2014-08-07 |
US20170130095A1 (en) | 2017-05-11 |
JP2017197735A (en) | 2017-11-02 |
KR20150127027A (en) | 2015-11-16 |
US20140213741A1 (en) | 2014-07-31 |
CN104736586A (en) | 2015-06-24 |
US10208227B2 (en) | 2019-02-19 |
EP2951222A1 (en) | 2015-12-09 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5895806A (en) | Polyurethane composition useful for coating cylindrical parts | |
US20170130095A1 (en) | Low free mdi prepolymers for rotational casting | |
TWI454527B (en) | Polyurethane resin composition and molded article thereof | |
US6747117B2 (en) | Polyurethane/urea composition for coating cylindrical parts | |
EP1033380B1 (en) | Polyurethaneurea elastomers for dynamic applications | |
JP2013510935A (en) | Accelerated curing of isocyanate-terminated prepolymers | |
US20060223967A1 (en) | Novel polyurea isocyanates | |
KR101790514B1 (en) | Method of manufacturing artificial leather using two-component type non-solvent polyurethane adhesive | |
KR20080005936A (en) | Water dispersible polyurethane composition | |
KR101105874B1 (en) | apparatus of polyurethane coating for roller | |
EP0982079B1 (en) | Method for producing cylindrical objects with multilayer coatings having dissimilar compositions without interfaces | |
CN116075536A (en) | Flexible polyurethane for flexible packaging adhesives free of aromatic amine migration | |
CN113950499B (en) | Two-component polyurethane composition for making large-size models and tools by 3D printing | |
WO2021202876A1 (en) | Polyurethane prepolymer composition comprising an alkyl benzoate | |
WO2019068531A1 (en) | Method and composition for rotational casting of polyurethane coating layer | |
US20040229996A1 (en) | Polyurethane composition for the production of foils | |
JPS6018514A (en) | Elastomer-forming composition | |
KR101499782B1 (en) | Polyurethane-urea coating material composition | |
KR20170100967A (en) | Adhesive polyurethane resin and dressing and product thereof | |
JP2013256558A (en) | Method for producing foam urethane sheet |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |