Classifications

• • 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
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
  • B29C33/60—Releasing, lubricating or separating agents
• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/0001—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor characterised by the choice of material
• • 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
  • C08G18/3218—Polyhydroxy compounds containing cyclic groups having at least one oxygen atom in the ring
• • 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
  • B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
  • B29C67/24—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 characterised by the choice of material
  • B29C67/246—Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM]
• • 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
  • B29K2075/00—Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding 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
  • B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
• • 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
  • C08G2120/00—Compositions for reaction injection moulding processes

Definitions

• the present invention relates generally to processes and compositions for making molded articles that have improved properties.
• the molded articles are made for polymeric resinous materials, and are easily removed from a mold and preferably provide an improved surface for coating. More particularly, it relates to techniques and/or compositions involving the use of a reaction product of a glycoside and a fatty acid source to facilitate removal of molded resin products from molds and, preferably, to also provide an improved tie-coating surface to said molded resin products.
• Resins based on various polymers are used in the production of molded objects. In general, such resins must be thermoplastic or thermosetting in order to perform satisfactorily.
• thermoplastic resins include polyamides, polyesters, polyurethanes, polypeptides, ether and acetal polymers, polysulfides, polycarbonates, polyolefins, polystyrenes, polyvinyl chlorides, acrylonitrile butadiene styrene resins, acrylic resins, and the like.
• thermosetting resins include phenolic resins, amino resins, unsaturated polyester resins, epoxy resins, cross-linked polyurethanes, silicone polymers and similar resins.
• Resins based on organic polyisocyanates are well known and enjoy widespread commercial use in reaction injection molding (RIM) applications in which molded resin products are obtained through reaction of polyisocyanates with hydroxyl or amine containing molecules within a mold cavity.
• RIM reaction injection molding
• Polyurethanes constitute a broad class of polymeric materials having a wide range of physical characteristics. The polymers are produced through the interaction of a polyisocyanate with a chemical compound having two or more active hydrogen atoms in its structure such as a polyol, or polyether/polyester that contains active hydrogen groups in the form of amines, amides or hydroxyls, or mixtures of two or more of such materials.
• This component used in preparing the polyurethane is generally termed in the art as an "active-hydrogen-containing material" and is generally liquid, or a solid capable of being melted at a relatively low temperature.
• the materials most typically used contain hydroxyl groups as the radicals having the active hydrogen and thus are generally termed "polyols.”
• polyols The preparation of polyurethanes is disclosed, for example, in U.S. Pat. No. 2,888,409 issued May 26, 1959 and in the patents referred to therein.
• other hydroxyl-capped polymers useful as the polyol in preparing polyurethane resins include polyformals as described, for example, in U.S. Pat. No. 3,055,871 issued Sept.
• the present invention is a process for the production of molded articles from a polymeric resinous material comprising the steps of:
• this invention is a process for preparing a reaction injection molded polyurethane product, which process comprises the steps of:
• a mold release agent comprising a glycoside compound containing at least one fatty acid ester or ether, said mold release agent being employed in an amount ranging from 0.1 to 10 percent of the weight of said polyol.
• the above-described fatty acid ether or ester glycoside mold release agents can also function as tie coat agents to impart improved surface coating characteristics to the aforementioned molded resin compositions.
• the above-described polyurethane reaction injection molding process further comprises a step in which a surface coating material is applied to the resulting molded polyurethane product.
• the mold release agent is a reaction product of a glycoside and a free fatty acid, a lower alkyl ester of a fatty acid, a fatty acid halide or anhydride, a fatty glyceride, olefin oxide, long chain alkyl halide or a mixture of such reaction products.
• this reaction product contains a complex mixture of esters or ethers which may include mono-, di, tri- and tetra-esters or ethers of glycoside and, when a fatty glyceride component is employed to form said reaction product, the resulting product mixture will also contain mono-, di- and tri-esters of glycerol as well as a glycerol per se.
• glycoside compounds can be quite suitably employed as external mold release agents in resin molding processes or operations, it has been found to be much preferred to employ same instead as internal mold release agents.
• glycosides suitable for use herein include those represented by the formula:
• R is an organic residue (preferably alkyl) containing from 1 to 20 carbon atoms and G is a moiety derived from a reducing saccharide containing 5 to 6 carbon atoms.
• the R group may also be substituted such as with a hydroxyl group.
• the glycoside of the Formula A may include a group (e.g., ethylene oxide, polyethylene oxide, propylene oxide, polypropylene oxide, etc.) between the organic residue, R, and the saccharide moiety, G.
• the R group is a straight chain alkyl, having a carbon chain length of 1 to 20 and most preferably R is a lower alkyl group of from 1 to 5 carbon atoms.
• the glycoside is methyl glucoside.
• O is an oxygen atom and provides the linkage (ordinarily formed through an acetal mechanism) between the alkanol which is the basis of the alkyl group in the preferred glycosides, and the saccharide.
• the saccharides employed herein are fructose, glucose, mannose, galactose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxose and ribose.
• the degree of polymerization is determined as an average value from the number represented by x.
• the average value of x will generally be between 1.0 and about 10 for glycosides employed in the present invention.
• G may be comprised of a composite or combination of more than one type of saccharide moiety. Examples include sucrose, raffinose, stachyose, etc.
• glycosides utilized herein may be prepared according to the process described in U.S. Pat. No. 4,223,129 issued Sept. 6, 1980 to Roth et al.
• the source of the glycoside is not crucial to the present invention; therefore, any source of the glycoside may be utilized.
• materials containing alkoxy groups such as ethylene or propylene oxide pendant from the saccharide may be used. Such materials are described in pending U.S. patent application Ser. No. 06/704,828 filed Feb. 22, 1985 by Roth et al.
• glycoside mold release agents have also been found to impart tie coating properties to the surface of the molded resin product. More specifically, said mold release agents improve the surface characteristics of said products and thereby promote or facilitate enhanced adhesion of various coating materials thereto.
• the mold release agents of this invention may be used in a wide variety of molded resin compositions.
• such resins must be thermoplastic or thermosetting in order to perform satisfactorily.
• thermoplastic resins include polyamides, polyesters, polyurethanes, polypeptides, ether and acetal polymers, polysulfides, polycarbonates, polyolefins, polystyrenes, polyvinyl chlorides, acrylonitrile butadiene styrene (ABS) resins, acrylic resins, and the like.
• ABS acrylonitrile butadiene styrene
• the thermoplastic resins are solidified in a mold by cooling the resin to a temperature below its solidification temperature.
• thermosetting resins examples include phenolic resins, amino resins, unsaturated polyester resins, epoxy resins, cross-linked polyurethanes, silicone polymers and similar resins. Thermosetting resins are solidified in molds via an internal crosslinking reaction.
• a general embodiment of this invention is to use the glycoside compound containing one or more fatty acid ester or ether groups in sufficient amount to function as a mold release agent in the production of molded polymeric resinous articles.
• the glycoside component may be used as an internal mold release agent, as an external mold release agent, simultaneously as both internal and external mold release agents or as an external mold release agent in combination with coating materials.
• a preferred embodiment of this invention entails the use of the mold release agent in reaction injection molded polyurethane products.
• a process is provided in which polyurethane products are produced by reacting a mixture containing polyisocyanate, and an organic compound containing hydrogen atoms reactive with the polyisocyanate, preferably a polyol or mixture of polyols, in the presence of a catalyst and in the presence or absence of water and/or organic blowing agents, and optionally other additives.
• the mold release agent of this invention is present during the above reaction and provides the basis for the internal mold release function. It is to be noted that the mold release agent is not separately reacted with the polyisocyanate component prior to the reaction injection molding operation.
• the mold release agents are preferably provided, in accord with the invention, by either of two different processes, one being alcoholysis with triglyceride oils or fats (alcoholysis process, AP); and the other being alcoholysis with lower alkyl esters of fatty acids (esterification process, EP).
• a triglyceride oil such as soybean oil, linseed oil, palm kernel oil, sunflower oil, canola oil, coconut oil, tung oil, lard, tallow or marine oils, preferably soybean oil, coconut oil or linseed oil
• an alcoholysis catalyst such as lithium carbonate, lithium hydroxide, potassium hydroxide, lithium ricinoleate, dibutyltin oxide or titanate esters until equilibrium is reached.
• alcoholysis process is conducted at a temperature above about 200° C. and below about 270° C.
• the molar ratio of triglyceride to alkyl glycoside in the AP reaction is typically in the range of about 1.0:0.1 to about 1.0:2.25.
• the AP reaction is conducted in a fashion such that the resulting reaction product contains less than 1% glycerol.
• the fatty portion of the triglyceride may be saturated or unsaturated, and should have a chain length of between 6 and 24 carbon atoms, preferably between 8 and 20 carbon atoms, for best results.
• the unsaturated oils are preferred since they provide liquid reaction products with low viscosities. They also provide cross-linking capabilities at the surface of the polyurethane. Further, the reaction should be controlled to provide the desired levels of mono, di, tri and tetresaters in order to obtain the best surface characteristics for the polyurethane product.
• the predominant amount of the combined weight of the glycoside ester mold release agent components be di-,tri- and tetra esters and preferably that the monoester component constitute less than 50 percent of the glycoside ester content.
• the residual free glycoside content of the AP reaction product should be 8 percent maximum, preferably less than 5 percent, and most preferably less than 2 percent.
• the mold release agent produced by the AP process should have a hydroxyl number of between about 19 and about 615.
• the molecular weight of the reaction product should be in the range of between 290 and 1380.
• the fatty acid component should have a carbon chain length of between 6 and 24 carbon atoms and the fatty acid may be saturated or unsaturated, although unsaturated fatty acids are preferred as in the case of the AP reaction using triglyceride oils.
• the esterified glycoside should have less than 10% of free fatty acid or metallic soap, thereof.
• the esterified product should have the desired levels of mono, di, tri and tetraesters so as to provide the desired surface characteristics.
• the molar ratio of fatty acid esters to glycoside in the EP reaction mixture should be in the range of about 1:1 to about 3.5:1, preferably 1.5:1 to 2.5:1.
• the free glycoside content of the product should be less than 20 percent, preferably less than 5 percent, and most preferably less than 2.0 percent.
• the hydroxyl number of the EP reaction product should be in the range of 19 to 615.
• the reaction is typically carried out at a temperature between about 140° C. and 200° C. using potassium or sodium hydroxide or corresponding fatty soaps, thereof.
• the fatty portion of the fatty acid ester or glyceride should have a chain length of between 6 and 24 carbon atoms and a degree of unsaturation, as measured by Iodine Value, between about 0 and 465 for best results.
• the mold release agent can be economically prepared and effectively used in the production of molded resinous compositions having highly desired mold-release and surface coating characteristics.
• the glycoside compound When used as an internal mold release agent, the glycoside compound should be present in the molded composition at a level between about 0.1 and 10 percent, preferably about 0.5 about 5 percent, based on the weight of the resinous material.
• the mold release agent is introduced into a mixture prepared for producing polyurethane, including an organic polyisocyanate, a polyol, a catalyst, and, optionally, a blowing agent.
• the mold release agent of the invention is included in an amount of between about 0.1 percent and 10 percent, preferably 1 to 5 percent, of the resinous material.
• Polyols include organic compounds with a molecular weight generally between 62 and 10,000 which contain at least two hydrogen atoms capable of reacting with isocyanates. These may be compounds which contain amino groups, thio groups or carboxyl groups but are preferably organic polyhydroxyl compounds, in particular polyhydric alcohols containing 2 to 8 hydroxyl groups and especially those having a molecular weight of 800 to 10,000, preferably 1000 to 6000, e.g. the polyesters, polyethers, polythioethers, polyacetals, polycarbonates and polyester amides containing at least two, generally 2 to 8, but preferably 2 to 4 hydroxyl groups which are known per se for the production of homogeneous and cellular polyurethanes.
• Conventional polyurethane molding parameters including normally employed temperatures, pressures, and the like, are used to produce the molded polyurethane containing the mold release agent.
• the mixture can be injected into and reacted within a mold and, at the end of the reaction, the polyurethane is readily removed from the mold.
• the product readily releases from the mold because of the presence of the mold release agent of the invention and can readily be coated with a variety of formulations including those based on drying oils.
• a 1,000 milliliter, three-neck flask is provided with a mechanical stirrer and a nitrogen gas tube to provide a nitrogen gas blanket within the flask.
• a water-cooled condenser is provided above the flask and communicates with the flask.
• a thermometer is introduced into the flask and a trap is employed to collect material from the condenser.
• the flask is heated by means of an electric mantle.
• the oil is added first and heating is commenced, followed by the addition of the remaining ingredients under a nitrogen gas blanket. When the temperature reaches 240° C. there is some reflux and the nitrogen gas is cut off. The temperature of the reactants is maintained at 245°-250° C. for 75 minutes whereupon the mixture is cooled to 180° C. before being filtered. After filtering, the clear liquid solidifies on further cooling to a soft wax, the wax having a melting range of 100° to 110° C.
• the mold release agent of the invention obtained above has good solubility in methanol and a Gardner color of about 13.
• the calculated hydroxyl number is 306.5 and by analysis is about 303.
• This mold release agent is introduced into a conventional polyisocyanate mixture comprising 80.8 grams of polyisocyanate and 121.95 grams of a high molecular weight polyol, NIAX® polyol 40-34 produced by Union Carbide, and 14.44 grams of ethylene glycol.
• the mold release agent is employed at a level of 3.5 percent of the total resinous material in the reaction mixture.
• the polyurethane is allowed to develop in a mold and, upon completion of the reaction, the product is readily released from the mold in which it is formed.
• the mold release agent is prepared by a two step EP process (esterification process) in which methyl esters of fatty acids are first prepared and then they are reacted with methyl glucoside. More particularly, soybean oil is reacted in methanol in the presence of sodium hydroxide, as a catalyst, at about 62° C. for 1.5 hours. Methyl soy esters and glycerol are formed, and the glycerol separates out of the reaction mixture.
• the mold release agent produced by the esterification process is then made in a 5 liter, 3 neck flask equipped with a nitrogen gas connection, a mechanical stirrer having a Teflon blade, and a thermometer.
• a takeoff is provided which communicates with a water cooled condenser connected to an ice cooled receiver. The flask is heated by means of an electric mantle.
• methyl soy esters To the three neck flask is added 1980 grams of the methyl soy esters; 582 grams of methyl glucoside, available from A. E. Staley Manufacturing Company as STA-MEG 104; 19 grams of potassium hydroxide dissolved in 43.8 grams of methanol; and an additional 162 grams of the methyl soy ester being included to allow for potassium soap formation.
• the flask and contents under a nitrogen blanket are slowly heated (52 minutes) to 140° C. and 176.7 grams of methanol is collected in the ice cooled receiver.
• the reaction mixture is then cooled to 108° C. with gradual application of 3 KPa vacuum to keep foaming under control.
• the reaction mixture is reheated to 170° C. until there is no more methanol formed in the ice cooled receiver (50 minutes above 155° C.).
• An additional 171.1 grams of methanol is collected.
• the resulting mold release agent is cooled to ambient temperature.
• the product has a Gardner color of 14-15; a molecular weight of 750; a hydroxyl number of 167; and a Brookfield viscosity of 454 cp.
• the mono, di, tri and tetraester content is 39%, 39%, 18%, and 3%, respectively.
• the mold release agent of Examples 1 and 2 is incorporated into an otherwise conventional, commercial polyurethane formulation, the polymerization mixture comprising the following per hundred parts high molecular weight polyol:
• the mold release agent from Examples 1 and 2 is added at a level of 1 to 10 percent based on the total resinous material weight.
• Molded polyurethane products produced from the foregoing formulation exhibit superior mold release characteristics as compared molded polyurethane products made in the absence of external mold release agents.
• the surface of the polyurethane exhibits improved binding of the coatings.
• the mold release agent of Example 2 was used as an internal mold release agent in a molded article produced from bulk molding compound (BMC). The following ingredients were combined and mixed in a Hobart mixer:
• the BMC mixture containing the glycoside mold release agent was cured in plates in a Carver type press at 6900 KPa pressure at 150° C. for 3 hours.
• the plates containing the internal mold release agent of this invention readily released from the mold and had a more uniform appearance than a control made with an equivalent amount of zinc stearate as a mold release agent.
• the plates were subjected to various physical testing procedures to evaluate their tensile and flexural properties.
• zinc stearate was used as an internal mold release contact
• Run B used the mold release agent of Example 2 as the internal mold release agent. Characteristics of the plates were as follows:

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• Manufacturing & Machinery (AREA)
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• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Polyurethanes Or Polyureas (AREA)

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Cited By (6)

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Citations (11)

• 1985
  • 1985-05-20 US US06/735,900 patent/USH444H/en not_active Abandoned
• 1986
  • 1986-05-16 EP EP86903844A patent/EP0225914A1/en not_active Withdrawn
  • 1986-05-16 WO PCT/US1986/001079 patent/WO1986007003A1/en unknown
  • 1986-05-19 ES ES555093A patent/ES8707986A1/es not_active Expired

Patent Citations (11)

Non-Patent Citations (1)

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