MXPA97002992A - Parts molded by injection of reaction, reinforced, low density, which have an improved coefficient of linear thermal expansion and properties of deflection of the ac - Google Patents

Abstract

The present invention relates to injection molded parts, reinforced (RRIM), polyurethane-polyurea, rigid, low density, low molecular weight, which have reinforcing fibers of glass flakes dispersed through a matrix obtained by the reaction of the polyisocyanates with a hydroxyl tertiary amine tertiary amine polyether polyol-containing resin, a blowing agent and, optionally, surfactants, chain elongation agents, and urethane-promoting catalysts. The low density RRIM piece, which uses the glass flakes and tertiary amine polyether polyols, is low cost, alternative to low density pieces, reinforced with glass fibers, and this piece exhibits a relatively low coefficient linear thermal expansion and relatively high temperature deviation properties, compared to other known landfills

Description

MOLDED PIECES BY REACTION INJECTION. REINFORCED. LOW DENSITY. WHICH HAVE AN IMPROVED COEFFICIENT OF LINEAR THERMAL EXPANSION AND PROPERTIES OF HEAT DEFLECTION FIELD OF THE INVENTION The present invention relates to the field of reinforced reaction injection molded parts (RRIM). More particularly, the present invention pertains to reactive systems containing tertiary hydroxyl tertiary amine polyols as the matrix for water-blown, fiber-reinforced molded parts having an improved coefficient of linear thermal expansion and heat deflecting properties. , as determined by fractional factorial methods of design experiments. BACKGROUND OF THE INVENTION Reaction injection molding (RIM) systems have become increasingly important for the production of many commercially useful products, such as automobile belts. However, many of the reactive systems used so far contain extensive polyurethane-polyurea linkages, which have relatively low thermal deflection temperatures and lack the flexural modulus and tensile strength necessary for many applications. The chemistry of these reactive systems it involves the use of a "side A" and a "side B" of polyisocyanate, which employ a mixture of compounds containing reactive isocyanate hydrogens. These "B side" components generally include one or more hydroxyl functional polyethers or polyesters-polyols, and one or more hindered diamines. The polyol components react with the isocyanate to form urethane linkages, while the amine components react to form urea linkages. These systems are described, for example, in U.S. Patent No. 4,218,543 to Weber. To improve the flexural modulus and the tensile strength of the RIM parts, glass mats reinforced with woven fibers and non-woven fibers have been used. These mats are cut with the mold configuration and placed on the surface of this mold. The handling of these mats is often difficult and irritates the skin, and requires time to cut and place them inside the mold. Other methods of improving the flexural modulus and tensile strength of the RIM parts are short fiber mixtures cut into the side component B of the resin and injecting the resin containing the isocyanate fibers into the mold (RRIM). This process is also well known and has been proposed as a resource for the manufacture of high density parts that require resistance in applications, such as in external parts of the body of a car. Various types of fillers, such as mica, glass and olastonite have been proposed as reinforcing agents in the high density RRIM. For example, U.S. Patent Nos. 5,036,118, 4,943,603 and 4,871,789 disclose the use of mica or wollastonite as reinforcement, predominantly in high density systems (specific gravity> 1.0), suitable for use in exterior panels. bodies. More recently, the use of RRIM for automotive interior parts has been investigated. In order to further improve standards for increasing fuel efficiency, the industry is continually seeking ways to reduce the weight of auto parts, while maintaining its necessary functional strength. Therefore, the interior parts of the body, where the requirements of flexural modulus, tensile strength and impact resistance are not as severe as in the body's outer panels, the RRIM parts of low density have been investigated as alternatives for heavier metals, wood fibers, interior parts of ABS and PP. As part of the present invention, the inventor has discovered that when combined with a particular matrix resin, ground glass flakes, alone or in combination with other reinforcing materials, is an excellent alternative for glass fiber reinforcements. in the low density RRIM. It has also been found that by using the hydroxyl functional tertiary amine polyether polyols, a RRIM piece having a good modulus of flexure, tensile strength and impact resistance can be produced. Such a polyol also reduces the demolding time and, at least in one embodiment, reduces the viscosity of the resin for ease in the process, does not require the use of chain extenders / interleavers and requires small amounts of urethane-forming catalysts . Moreover, it has been discovered by the inventor, through the use of factorial and fractional design experiment methods, that the use of certain fillers, in association with the hydroxyl functional tertiary amine polyether polyols, surprisingly results in to RRIM products that have both a low coefficient of linear thermal expansion and high heat deflection temperatures, compared to other similar systems. By controlling the amount, type and orientation of the filler or mixture of fillers used, as well as the density of the compound, the ratio of components (resin / isocyanate) and mold temperature, the strength and physical properties of the resulting product can be adapt to the needs of customers.

The coefficient of thermal expansion (CLTE), the heat deflection temperature (HDT) and the dimensional stability of low density RRIM products become increasingly important as the size of RRIM products increases. For example, the CLTE becomes important due to the size and complexity of the product as it is released to the tolerances established in the industry. HDT becomes an important consideration due to the structural functions that the part must perform, ie the support of other components, such as radios, heater controls and glove compartment assemblies on dashboards formed from RRIM materials of low density. Therefore, it is desirable to form low density RRIM components that have a relatively low coefficient of linear thermal expansion and high heat deflection temperature properties. COMPENDIUM DB THE INVENTION The present invention relates to rigid, low density, low weight RIM components, which employ milled glass flake fillers, dispersed through a matrix, which comprises the reaction product of a component of isocyanate and a resin component containing hydroxyl-functional tertiary amine polyether polyols, a blowing agent and, optionally, one or more compounds selected from the group consisting of urethane promoting catalysts, chain extenders and surfactants. The present invention also relates to a method for determining the optimum type of padding, concentration and orientation for a given component, formed by the rigid low density RRIM. DETAILED DESCRIPTION OF THE PREFERRED MODALITY The present invention relates to low density RRIM reagent systems, comprising a side component "A" and the "B" side of polyisocyanate, which includes a mixture of compounds containing isocyanate reactive hydrogen , which form a matrix through which a reinforcing filler that includes crushed glass flakes is dispersed. The organic polyisocyanates that can be used for the side component "A" include the aromatic, aliphatic and cycloaliphatic polyisocyanates and combinations thereof. Representative of these types are diisocyanates, such as m-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanates, diisocyanate hexamethylene, tetramethylene diisocyanate, cyclohexane 1,4-diisocyanate, hexahydrotoluene diisocyanate (and isomers), naphthalene-1, 5-naphthalene diisocyanate, 2,4-diisocyanate, 1-methoxyphenyl diisocyanate, diisocyanate of 2,2'-, 2,4'-, and 4,4'-diphenylmethane, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl, diisocyanate, 3-diisocyanate, 3'-dimethyl-4,4-biphenyl and 4,4 '3,3'-dimethyldiphenylmethane diisocyanate; the triisocyanates, such as the 4,4-, 4"-triphenylmethane triisocyanate and toluene 2,4,6-triisocyanate, and the tetraisocyanates, such as 2,2 ', 5,5'-tetraisocyanate 4.4. '-dimethyldiphenylmethane, and polymeric polyisocyanates, such as polyethylene-polyphenylene polyisocyanate, especially useful due to their availability and properties are 4,4'-diphenylmethane diisocyanate and polymethylene-polyphenylene polyisocyanate. "Polyisocyanates can also be used. without treatment in the compositions of the present invention, such as the untreated diphenylmethane isocyanate, obtained by the phosgenation of the untreated diphenylmethane diamine The preferred or untreated isocyanates are described in US Patent No. 3,215,652. useful are the modified polyisocyanates, examples of which include the polyisocyanates containing a urethamyminecarbodyl group (German Patent No. 10 92 007), the polyisocyanates containing a group of allophanate (British Patent No. 994,890; Belgian Patent No. 761,626), polyisocyanates containing an isocyanurate group (German Patents Nos. 10 22 789, 12 22 067, 10 27 394, published German patent applications, Nos. 19 29 034 and 20 04 048), polyisocyanates containing a urethane group (Belgian patent No. 752,261, US patent No. 3,394,164), polyisocyanates containing a biuret group (German patent No. 11 01 394, British Patent No. 889,050) and polyisocyanates containing an ester group (British Patent Nos. 965,474, 1,072,956, US Patent No. 3,567,763, German Patent No. 12 31 688), all of which are incorporate here as a reference. Preferably used are the aromatic di- and poly iso-cyanates optionally containing a urethamimine-carbodiimide group and a urethane group, such as the 2,2'-, 2,4'-, 4,4-diphenylmethane diisocyanate. (MDI), as well as any desired mixture of these isomers and mixtures of 2,2'-, 2,4'-, 4,4'-diphenylmethane diisocyanates and polyphenylenepolymethylene polyisocyanates (untreated MDI). Preferably used is a 4,4 '-MDI composition modified with uretonimine-carbodiimide, containing from 10 to 40 weight percent of modified MDI and from 60 to 90 weight percent of 4,4' -MDI, containing optionally less than 10 weight percent of 2,2'- and 2,4'-MDI, these weight percentages are based on the weight of the 4,4'-MDI composition modified with the uretonimine-carbodiimide. The weight ratio of uretonimine to carbodiimide ranges from 20: 1 to 1: 1.

Apparent prepolymers are also preferred, such as urethane-modified MDI, obtained by the reaction of a low molecular weight polyhydric compound (< 400) with 4,4'-MDI, the final product contains, for example, 40 to 60 weight percent of the urethane prepolymer and 40 to 60 weight percent of the 4,4-MDI. Other modifications include forming a quasi-prepolymer by the reaction of the modified MDI with the uretonimine-carbodiimide, modified with allophanate or modified with biuret, with a polyhydric compound of low or high molecular weight. The aforementioned isocyanates can be used in simple form or as mixtures with other isocyanates to obtain the desired physical properties, viscosity and freezing point. For example, untreated MDI can be mixed with the 4,4'-MDI and 2, '-MDI; or the modified MDI can be mixed with the uretonimine-carbodiimide with a urethane-modified MDI and an optionally untreated MDI. These mixtures can then, if desired, be reacted with a polyhydric compound to obtain an apparent prepolymer. The resin component of side B contains a hydroxyl functional tertiary amine polyether polyol prepared by the oxyalkylation of an aliphatic amine or aromatic with ethylene oxide, propylene oxide or mixtures thereof. Examples of suitable aromatic amines which are useful as initiators include the various phenylenediamines, toluenediamines and diphenylmethanediamines. Examples of suitable aliphatic amines include ethylenediamine, propylene diamine, 1,4-butanediamine, 1,6-hexanediamine, diethylene triamine, triethylene tetraamine and the like. The hydroxy alkylamines may also be useful, for example, 2-hydroxyethylamine and 2- and 3-hydroxypropylamine, bis (2-hydroxyethyl) ethylamine, tris (2-hydroxyethyl) amine, and the like. Preferred initiators are monoethanolamine, ethylenediamine, 2-hydroxypropylamine and bis (2-hydroxyethyl) -2-hydroxypropyl amine. The amine or hydroxyalkylamine initiators are oxyalkylated with sufficient alkylene oxide to convert at least one and preferably all the amino groups to tertiary amino groups. The alkylene oxides may be mentioned, such as ethylene oxide and propylene oxide. Mixtures of these alkylene oxides can be used; or they or their mixtures can be used in sequence to form homopolymer, block, heteric or block-hetheric polyether polyols. The process of preparing these polyether polyols is conventional and is well known to those skilled in the art.

Preferred tertiary amine polyether polyols, preferred hydroxyl polymers are polyoxyethylated polyoxyethylated monoethanolamines containing a primary hydroxyl group cap, such as polyoxyethylene, from 5 to 35 weight percent, preferably from 20 to 30 percent by weight. cent in weight. Additional preferred tertiary amine polyether polyols, further preferred hydroxyl functional groups are polyoxyethylated polyoxyethylated ethylenediamines capped with polyoxyethylene groups in an amount of 5 to 35 weight percent, preferably 10 to 20 weight percent. Mixtures of these two polyols are also suitable, preferably in weight ratios of the polyether polyol initiated with monoethanolamine to the polyether polyol initiated with ethylenediamine, from 9: 1 to 2: 1, with no other polyol being mixed. The resin component of side B preferably contains 10 percent by weight, more preferably 20 to 100 percent by weight, of the tertiary amine polyether polyol, hydroxyl functional based on the weight of all polyether polyols in the resin. Suitable amounts of the tertiary amine polyether polyol contained in the resin component range from 10 to 99 weight percent, preferably from 20 to 99 weight percent, more preferably from 50 to 99 weight percent, based on the weight of all the reactive compounds in the side resin component B. Reactive compounds include all ingredients, except wollastonite fibers and other optional fillings and fibers, insoluble at room temperature. In a more preferred embodiment of the invention (all (100% by weight) the polyether polyols in the resin consist of the tertiary amine polyether polyols, terminated in primary hydroxyl groups, and the resin lacks any elongation or crosslinking agent The average functionality of the tertiary, functional hydroxyl amine polyether polyols is from about 2.5 to 6, preferably from about 2.8 to 4.0, with average equivalent weights being from about 50 to 3,000.The polyols with lower functionalities and higher molecular weights tend to make a more flexible low density foam and increase the impact resistance at the cost of the flexural modulus A high functionality polyol, of lower molecular weight, will increase the interlacing density and the flexural modulus of the It has been found that a high flexural modulus can be advantageously achieved by using high functionality polyols and maintaining the resistance to impact of the foam, by mixing a low molecular weight polyol with a high molecular weight polyol. Thus, in a preferred embodiment, a trifunctional low molecular weight polyol is mixed with a polyol tertiary functional high molecular weight, to obtain a foam that has good flexural modulus, while maintaining a satisfactory impact resistance. Polymer-modified polyr polyols can be mixed in higher or lower amounts with the hydroxyl functional tertiary amine polyr polyols. Some such polymer modified polyr polyols are known as graft polyols. These graft polyols are well known in the art and are prepared by the in situ polymerization of one or more vinyl monomers, preferably acrylonitrile and styrene, in the presence of a polyol r or polyol polyester, particularly polyols containing a lower amount of natural or induced unsaturation. Mds for preparing these graft polyols can be found in columns 1-5 and in the Examples of the patent of E. U. A., No. 3,652,639; in columns 1-6 and in the Examples of the patent of E. U. A., No. 3,823,201; particularly in columns 2-8 and n Examples of the patent of E. U. A., No. 4,690,956; and in the patent of E. U. A., No. 4,524,147; All these patents are incorporated herein by reference. The use of graft polyols can increase the flexural modulus and the tensile strength of the foam. Polyols modified with non-graft polymers are also suitable, for example, those prepared by the reaction of a polyocyanate with an alkanolamine, in the presence of a polyol, as taught in the patents of U. U.A., Nos. 4,293,470, 4,296,213 and 4,374,209; the dispersion of the polyisocyanurates containing pendant urea groups, as taught in U.A. Patent No. 4,386,167, and the polyisocyanurate dispersions which also contain biruet bonds, as taught in U.S. Patent No. 4,359,541. Other polyols modified with polymers can be prepared by in situ size reduction of the polymers until the particle size is less than 20 microns, preferably less than 10 microns. Also useful in minor amounts with the amine initiated polyr polyols, which have free amino hydrogens and functional polyoxyalkylene hydroxyl moieties, in admixture with the tertiary amine polyol. These polyols are prepared as taught in the patent of E. u. A., No. 4,517,383, by the oxyalkylation of an aliphatic or aromatic amine with a stoichiometric excess of the alkylene oxide, but using an extraordinarily high amount of the basic oxyalkylation catalyst, which must be present at the start of this oxyalkylation . Such asymmetric polyols of double functionality create both urne and urea bonds in the finished product, and also have the advantage of lower viscosities than their fully oxidized symmetric analogues.

In order to promote rapid demolding times, it is preferred that at least one of the polyr polyols, more preferably all of these polyr polyols, be terminated with primary hydroxyl groups rather than secondary hydroxyl groups. Functional hydroxyl and functional amine chain extenders are optional and include functional hydroxyl chain extenders, such as lene glycol, glycerin, trimlolpropane, 1,4-butanediol, propylene glycol, dipropylene glycol, and the like. , 6-hexane diol, and the like; and functional amine chain extenders, such as sterically hindered diltoluenediamine, and other hindered amines disclosed in US Pat. No. 4,218,543 to eber, phenylene-amine, 1,4-cyclohexan-bis- ( mlamine), lenediamine, dilenetriamine, N- (2-hydroxypropyl) lenediamine, N, N'-di (2-hydroxypropyl) lenediamine, piperazine, and 2-mlpiperazine. In low density RRIM systems, the amount of the chain extender is generally less than 30 percent by weight, based on the total weight of the resin component, preferably less than 25 percent by weight, more preferably no extender agent. chain is present. In resin components containing exclusively functional tertiary amine polyols of hydroxyl, chain extenders are not necessary. Plasticizers can also be optionally used in the present invention in low density RRIM systems. In these low density RRIMs, the amount of the plasticizer is generally less than 25 weight percent of the total resin component (side B). Mold releasers, both external and internal, can be used. Internal mold release agents are generally mixtures of long chain carboxylate salts, particularly substituted ammonium stearates and ammonium stearates, and calcium and zinc stearates. External mold releasers are well-known commercial products and include waxes and silicones. In low density RRIM systems of the invention, a blowing agent is necessary. Water is the preferred blowing agent and can be used in amounts of up to 4 percent by weight, preferably less than 1.0 percent by weight, more preferably less than 0.5 percent by weight of the resin component (side B). The density of the foam decreases with the higher water content. When water is used as the blowing agent, the isocyanate component increases proportionally. The calculations of the amount of water required and the isocyanate required are performed routinely by those skilled in the art of polyurethane and polyisocyanurate foams. Chlorofluorocarbons (CFCs) and other volatile organic compounds can also be used as blowing agents, either alone or in combination with water. When used alone, the blowing agents of CFCs and other halogenated organic products, such as methylene chloride, are generally used in amounts up to 30 percent by weight of the polyol component, preferably 15 to 25 percent. in weigh. Other volatile organic compounds, such as pentane, isopentane, acetone and the like, are used in correspondingly smaller amounts, due to their lower molecular weights. When CFC type blowing agents are used, such as co-blowers, they are used in minor amounts, for example, up to 20 weight percent of the polyol component. Preferred are HCFS that have an ozone depletion potential of 0.05 or less. Other reactive blowing agents can be used in conjunction with water, such as tertiary alcohols and formic acid. You can also use agenets that retard the flame, when required by the formulation. Suitable agents that retard the flame are well known to those skilled in the art; but low molecular weight halogenated phosphate esters, biphenyls, can be used poihalogenates, biphenyloxides and the like, when agents that retard the flame are necessary. Since the presence of these agents that retard the flame generally causes a decrease in physical properties, their use is not preferred. The stabilizers and absorbers of ultraviolet radiation are also useful. These stabilizers generally act by absorbing ultraviolet radiation. Many agents that absorb ultraviolet radiation are commercially available, such as Uvinul® absorbent agents, manufactured by BASF Corporation, Mt. Olive, NJ. Suitable catalysts include the urethane and isocyanurate reaction promotion catalysts and are well known to those skilled in the art of polyurethanes. Suitable catalysts that promote the polyurethane include the tertiary amines, such as, for example, triethylene diamine, N-methylmorpholine, N-ethyl-morpholine, diethanolamine, N-co-morpholine, l-methyl-4-dimethyl-a-ino-ethyl-piperazine, -methoxypropyl dimethylamine, ethylamino-propyldiethyl amine, dimethylbenzylamine, and the like. Preferred catalysts are the amine catalysts, such as those commercially available from Air Products Chemical Company, under the name of DABCO® 33-LV. Other suitable catalysts are, for example, stannous chloride, dibutyltin di-2-ethylhexanoate, oxide stannous, dibutyl tin diacetate, dibutyltin dilaurate, as well as other organometallic compounds, such as those disclosed in the patent of US Pat. No. 2,846,408. Suitable amounts of the urethane catalyst are 1 percent by weight of the resin component, preferably less than 0.3 percent by weight. Catalysts that promote the isocyanurate include potassium acetate and potassium 2-ethylhexanoate, with potassium acetate being advantageously mixed as a solution in a glycol, such as ethylene glycol. A surfactant is also optional, but can be used in the production of high grade polyurethane foam, especially when polyols, in addition to the tertiary amine polyols, are used. The surfactants prevent the foam from collapsing and promote fine uniform cell structures. Numerous surfactants have been found satisfactory. Nonionic surfactants are preferred. Of these, nonionic surfactants such as well-known silicones have been found particularly convenient. Other surfactants include the polyethylene glycol ethers of long chain alcohols, the tertiary amine or alkanolamine salts of long chain alkyl acid sulfates, alkyl sulfonic esters, and alkyl acids. aryl sulphonic. Preferred surfactants are DC 190 and DC 193, silicon-containing surfactants, available from Dow-Corning, Midland, Mich. The flexural modulus, the temperature of heat distortion and the rigidity of the matrix can, in part, be adjusted by varying the urethane / isocyanurate content of the product. The isocyanurate content is increased by increasing the ratio of the isocyanate (side A) to the polyol (side B). In general isocyanate rates of from 80 to about 700 are useful, preferably from 95 to 250, and more preferably from 95 to 120. As mentioned above, it has been discovered by the inventor that a relatively low coefficient of linear thermal expansion and A high heat deflection temperature can be achieved by the low density RRIM products, by the use of a unique filler component, as determined by factorial and fractional methods of design experiments. The filler component of the present invention includes a predetermined amount of flake glass, and, optionally, one or more other fillers, such as ground glass and wollastonite, among others. Under a preferred embodiment, in terms of the CLTE and the HDT, the filler component will comprise at least 20.0% by weight, more preferably 50.0% by weight and even more preferably at least 80.0% by weight, based on the total amount of the filler component used. Generally speaking, other fillers in addition to flake glass should be used to reduce the cost, since the inclusion of filler components in addition to flake glass reduces the values of CLTE and HDT. The average diameter of the flake glass employed, as determined by the screen analysis, may vary from about 1.5875 to 3.175 mm, depending on the intended use of the product formed from the RRIM material. The flakes tend to have an extremely high stiffness at low load levels, compared to other reinforcement materials. Also, unlike micaceous materials, flake glass will generally not delaminate low voltage. The flake glass filler, used in accordance with the teachings of the present invention, may, optionally, but preferably, be treated with a coating composition, such as amioalkyl, chlorine, epoxy, vinyl and / or isocyanate coupling agents. , latex and titanate, among others. While any of numerous commercially available flake glass products can be used, one known as FLAKEGLAS®, available from NYCO Corporation has been found particularly useful.

Ground glass, which is essentially tubular fiber, having an average length about five times the width, is commercially available from numerous sources, including Owens Corning Fiberglass and PPG Industries, among others. The wollastonite, if employed, preferably has an aspect ratio greater than 2 and more preferably 10 or more, and the average particle size varies from 0.127 to 25.4 mm, more preferably from 0.813 to 6.35 mm, with 1.5875 mm being the more preferred. The wollastonite particles are also preferably treated on their surface to improve adhesion between the particles and the polymer matrix. The surface treatment employed may be a coating treatment applied to the surface of the particles as a chemical modification to the filling. Surface treatment agents and methods are well known to those skilled in the art and are disclosed in U.S. Patent Nos. 5,096,644, 4,582,887, 4,374,210, 4,218,510, 4,296,945, 4,689,356, 4,585,803 and 4,800,103, as well as in the article entitled Adhesion and Bonding in Composites, Ryuto or Yosomiya et al., Marchel Dekker, Inc., New York 1990, page 110-154, all of which are incorporated herein by reference. Preferred coatings include epoxy, chloro, isocyanate and amino-silane coupling agents.

Suitable amounts of the dispersed component filler through the RRIM piece vary from 10 to 20% by weight, based on the weight of the total composition, preferably from 12% to 18% by weight, or even more preferably from 14 to 16. % by weight, based on the total weight of the components, ie up to 35% by weight based on the weight of the polyol component. Methods of manufacturing RRIM molded products are well known in the art. The resin components are mixed and maintained at tank temperatures of 24 to 352V, preferably 29 to 352C, to reduce the viscosity of the resin. The isocyanate component "A" and resin component "B" are mixed by impact at pressures of approximately 140 kg / cm 2 and injected at approximately atmospheric pressure in an open mold, which is then closed and subjected to a pressure of 10.5 to 14 kg / cm2 in a closed mold. The mold is preheated to a temperature of 38 to 82 ° C, preferably to 55 to 65 ° C, more preferably to about 60 ° C, and may contain a substrate such as vinyl, placed on the surface of the mold. The raw material is usually injected into the center, after which the piece is demolded after a typical period of 1% to 4 minutes. , Using the tertiary amine polyols of the present invention, especially a predominant amount of the tertiary amine polyol initiated by monoethanolamine, of the invention, the reaction time is faster, reducing the curing time and demolding to 60 seconds or less. The following examples illustrate the nature of the invention and do not attempt to limit it in any way. Polyol A is a tertiary amine polyether polyol comprising an additive of propylene oxide and ethylene oxide of an ethylenediamine terminated with 15% by weight of ethylene oxide and has a nominal hydroxyl number of 62. Polyol B is a tertiary amine polyether polyol comprising an additive of propylene oxide and ethylene oxide of a monoethanolamine terminated with 26% by weight of ethylene oxide and contains about 55 weight percent of the polyoxypropylene with a hydroxyl number nominal of 500. Policat 46 is a mixture of 62/38% by weight of glycol and potassium acetate, respectively, available from Air Product Corp. The DABCO 33-LV is a mixture of 33/67% by weight of TEDA and DP6 respectively, available from Air Products Corp. T-12 is a dibutyl tin dilaurate curing agent, available from Air Products Corp. Isocyanate A is a mixture of isocyanates comprising about 60% by weight of the 4,4'- diisocyanate diphenylmethane, 5% by weight of the 2,4'-diphenylmethane diisocyanate, and 35% by weight of polymethylene polyphenylene polyisocyanate, of three or more rings. The A filler is a 0.397 mm flake glass, commercially available from NYCO Corp. under the FLAKEGLAS® name. The B filler is 0.397 mm ground glass, commercially available from Owens Corning Fiberglass. The filling C is made of wolastonite fibers, an acicular calcium metasilicate, commercially available from NYCO Corp .. under the name of G-RRIM Wollastrokup®, which has an aspect ratio of 15: 1. EXPERIMENTAL EXAMPLE Numerous plates obtained in a RIM 90 Cincinnati Milacron® machine and an Elastogran Maschinenbau machine (EMB) PU SV, equipped with a short stroke, high pressure impact mixer head, of 14 mm, were prepared to perform fractional factorial design experiments and determine which fillings offer the best values in terms of low CLTE and High HDT, when used in low density RRIM compositions of the present invention. Two heated molds, with the following dimensions: 91.44 cm x 91.44 cm x 0.3175 cm and 91.44 cm x . 4 cm x 0.9525 cm, respectively, were used to obtain plates for the physical properties measurement data.

The clamping presses used to mold the samples were a 75-ton Dake® press, available from JSJ Corporation of Grand Rapids, Michigan, and a 90 ton Cincinnati Milacron press. Both molds had a dividing line with doors, with repetitive style rear mixers. The long mold was injected from the end. The test specimens that are subjected to physical property measurements were cut parallel and perpendicular to the flow of the material, due to the orifice of the fiber fill. The four variables chosen to perform the fractional factorial design experiment were the mold temperature, fill load, ratio ratio and density, each variable being tested at a high and low level, as indicated in Table I. Table 1 MATRIX VARIABLE HIGH LOW Mold temperature, sc 71-74 60-63 Compound Density, kg / m3 608-656 528-560 Ratio ratio (isocyanate / resin) 100 100 Filler Load Compound 20 15 The remaining process conditions remained constant , as indicated in Table II.

Table II TYPICAL CONDITIONS OF THE PROCESS Materials Temperatures, sc Resin 32-35 Isocyanate 29-32 Production, gps 900 Impact Mixture Pressure, kg / cm2 Resin 105-126 Isocyanate 126-147 Demolding time, minutes 4 The experiment was performed three different times, each time using a different type of filler to determine its effect, if any, on the properties of the CLTE and the HDT. To perform the analysis, a standard resin composition of side B was prepared by mixing 63.48 parts of Polyol B in sequence; 7.0 parts of Polyol A; 0.75 parts of POLYCAT 46; 0.1 part of DABCO 33-LV; 0.3 part of water and 0..1 part of T-12 in an amount sufficient to form the various samples of RRIM tested. Samples separated from the standard were taken, to which a predetermined amount (ie 15.0 to 20.0 parts) of one of the A, B or C Fillers was added in two stages to meet the requirements of the loading level. The mixtures were made for approximately one hour or when the filling was completely dispersed, then pumped into a resin tank the day of the urethane machine. When the fill level 1 of the fill for each experiment was complete, the material was again emptied into the original drum from the machine, reweighed and adjusted at the level of 2. Next, the 100 parts of each sample of resin containing a different filler were reacted with 83 parts of the polyisocyanate A to form the various plates tested. The water level and catalyst were adjusted again to correct the reactivity profile after each catalyst addition. A total of eight operations were made for each type of fill. Each operation consisted of different combinations of mold temperature variables, fill load, density and ratio ratio. A total of 4 plates of each operation were obtained. The same eight operations were repeated for each type of fill, using extractions for the same batch of material. A total of 96 plates were obtained with 48 being for the physical test and the rest retained as duplicates. All test plates were allowed to cure for 48 hours before testing. The test specimens were cut using a rigid band saw blade to avoid subjecting the samples to stresses caused by the die cutter. Each sample plate subjected to the test had equal numbers of cut specimens parallel and perpendicular to the direction of material flow, due to the anticipated orientation of the fibers. The results of the physical tests were analyzed using the experimental methods of fractional factorial design, in which the data indicated in Table III were analyzed statistically in the deviation of the mean square to determine the factors that influence the HDT. The degree of magnitude of each of these influencing factors was also determined by means of the absolute values. As previously mentioned, it is advantageous to obtain the highest possible value for the HDT, especially when these properties relate to large pieces, such as substrates of instrument panels where the piece is expected to execute structural functions, such as support assemblies. radios, heater controls and glove boxes. Therefore, the total average of all high YBar values were calculated, including the high value of each tested factor, divided by the total number of factors (ie (148.0 + 143.75 + 149.5 + 145.5) 4 = 63.7SC for the HDT of the ground glass, in parallel).

Table III Average of all high YBar values = 146.7 ° F (63.72 ° C) * Average of all high YBar values = 133.4 ° F (56.33 ° C) Average of all high YBar values = 146.7 ° F (63.72 ° C) * Average of all high YBar values = 136.1 ° F (57.83 ° C) Average of all high YBar values = 154.3 ° F (67.94 ° C) Average of all high YBar values = 144 ° F (62.22 ° C) After determining the total average based on the highest YBar value for all the tested factors for both types of padding orientation, the response of the total average was determined for each type of padding tested, adding the average values for both parallel orientations and perpendicular and dividing by the total number of orientations tested (ie (154.3 + 144.0) / 2 = 149.152F (653C) for the glass in flakes). The HDT values of the substantially lower total average response were obtained for Wolastonite (ie 141.42F (60.8 ° -C)) and ground glass (140.1 ° -F (60SC)), respectively, which support the proposition that Glass flakes offer the best values in terms of HDT. Additionally, as illustrated in Table IV, the results of the physical test for the CLTE values with the use of fractional factorial design experiment methods were also analyzed for the mean square deviation to determine the factors that have the most influence in the CLTE. In contrast to the values of the HDT, it is advantageous to obtain the lowest possible value for the CLTE.

Table IV Average of all low YBar values = 4.38 Average of all low YBar values = 2.24 * Average of all low YBar values = 2.55 Average of all low YBar values = 2.62 To determine the total average response for each type of filler tested, the average for all YBar values for both types of pad orientation was summed and divided by the total number of orientations tested. In this respect, the total average response for flake glass was determined to be 2.19, while the total average response for wolastonite and ground glass was 2.40 and 4.03 respectively, thus supporting the proposition that glass flakes offer the best values in terms of the CLTE. Preferably, the resulting molding will have a linear thermal expansion coefficient of 4.0 x 10 ~ 5 or less and more preferably 3.5 x 10 ~ 5 or less, at the mold temperature. Additionally, it is preferred that the resulting molding, formed in accordance with the teachings of the present invention, will have an average specific gravity of about 0.8 g / cm 3 or less. While it will be evident that the preferred embodiments of the invention described are well calculated to comply with the objects indicated, it will be appreciated that the invention is susceptible to modifications, variations and changes, without departing from its spirit.

Claims (13)

1. CLAIMS 1. A reinforced reaction injection molded part of rigid cellular polyurethane, having a specific gravity of less than 1.0, which comprises: a) a matrix, which includes: i) an isocyanate component, comprising one or more polyisocyanates reacted with ii) a polyalkylene polyether polyol composition, comprising hydroxyl functional tertiary amine polyether polyols, a blowing agent, a catalyst promoting the polyurethane / isocyanate and, optionally, an elongation agent of chain, a surfactant and a stabilizer and b) a filler component, present in an amount of up to 20 weight percent, based on the weight of the total composition, this filler comprises at least 20 weight percent of glass flakes, based on the total amount of the filling composition, whereby the resulting molding has a coefficient of linear thermal expansion of approximately 4.0 x 10 ~ 5 'or less.
2. 2. The molded part according to claim 1, wherein its specific gravity is 0.8 g / cm3 or less.
3. 3. The molded part according to claim 2, wherein the glass flakes are included in the polyol composition before reacting with the isocyanate component.
4. 4. The molded part according to claim 1, wherein the hydroxyl functional tertiary amine polyether polyols are terminated in primary hydroxyl groups.
5. 5. The molded part according to claim 4, wherein the hydroxyl functional tertiary amine polyether polyols are selected from the group consisting of polyols initiated with the monoalkanolamine, polyols initiated with the alkylene diamine, and mixtures thereof.
6. 6. The molded part according to claim 5, wherein the hydroxyl functional tertiary amine polyether polyols are selected from the group consisting of the monoethanolamine initiated polyols, ethylene diamine initiated polyols, and mixtures thereof.
7. 7. The molded part according to claim 3, wherein 50 to 99 weight percent of the reactive ingredients in the "side B" resin consist of hydroxyl functional tertiary amine polyether polyols.
8. 8. The molded part according to claim 3, wherein the "B side" resin further contains polyether polyol dispersions of graft polymers.
9. 9. The molded part according to claim 2, wherein the amount of the filler used is between about 10 and 20 weight percent, based on the weight of the compound.
10. 10. The molded part according to claim 9, wherein the blowing agents consist of water.
11. 11. The molded part according to claim 9, wherein the wolastonite fibers. if they are used, they have an aspect ratio of 10 or greater, and a length of 0.762 to 6.35 mm.
12. 12. The molded part according to claim 2, wherein the modulus of flexure of the compound is from 10,500 to 14,700 kg / cm2 at a temperature of 222C
13. 13. A process for producing a reinforced reaction injection molded part of polyurethane rigid cell, having a linear thermal expansion coefficient of 4.0 x 10 ~ 5 or less, this process comprises the steps of: a) supplying i) an isocyanate component comprising one or more polyisocyanates reacted with ii) a polyoxyalkylene composition -polyether polyol, comprising tertiary amine polyether polyols, functional hydroxyl, a blowing agent, a catalyst that promotes polyurethane / isocyanate and, optionally, a chain elongation agent, a surfactant and a stabilizer; b) supplying a filler component, present in an amount of up to 20 percent by weight, based on the total weight of the composition, this filler comprises at least 20 percent by weight of glass flakes, based on the total amount of the filling composition; and c) introducing the filling component b) into the polyol composition ii), prior to the reaction with the isocyanate i).