(54) BLOCK COPOLYESTERS OF POLYBUTYLENETEREPHTHALATE(71) We, GENERAL ELECTRIC COMPANY, a corporation organised and existing under the laws of the State of New York, United States of America, ofI River Road, Schenectady 12305, State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to thermoplastic block copolyesters prepared by the transesterification of (a) straight or branched chain poly(l,4-butylene terephthalates) and (b) a polyester of a linear aliphatic dicarboxylic acid and, optionally, aromatic dibasic acids such as isophthalic or terephthalic acid with one or more straight or branched chain dihydric aliphatic glycols. The block copolyesters are useful as molding resin components and to enhance the physical properties of polyester resins.
Poly(l,4-butylene terephthalate) is a widely used molding resin because of its rapid crystallization and also because of its rigidity, good dimensional stability, low water absorption and good electrical properties. The resin also has a high heat resistance, inherent lubricity and excellent chemical resistance. One restriction on the use of this valuable resin, however, is the fact that the impact strengths of moldings tend to be somewhat inadequate for applications where the molded part is likely to be subjected to severe service conditions. This has led to work to upgrade this property of poly(l ,4-butylene terephthalate) because, both in straight and branched chain modifications, it is so superior to many other molding materials, especially with respect to its surface gloss when molded.
It has now been discovered that if a poly(l,4-butylene terephthalate) resin is chemically modified by being segmented in a copolyester in which a portion, preferably the major portion, of the repeating units are poly(l,4-butylene terephthalate) blocks and a portion, preferably the minor portion, of the repeating units are blocks of a polyester of a linear aliphatic dicarboxylic acid with one or more straight or branched chain dihydric aliphatic or cycloaliphatic glycols, and, optionally, an aromatic dibasic acid, such as isophthalic or terephthalic acid, then the resulting block copolyesters will have enhanced impact resistance, compared to the resin itself. The improvement in impact resistance is achieved with minimal loss of other physical properties and is accompanied with a measurable increase in toughness. It is believed that the presence of the internal blocks of other polyesters modifies the rate at which poly(l,4-butylene terephthalate) crystallizes from the melt in a very desirable manner.
In particular, if certain aliphatic, or partially aliphatic/aromatic, polyesters, are added to the reactor during the preparation of poly( 1 ,4-butylene terephthalate) after ester interchange between dimethyl terephthalate and 1 ,4-butanediol, there is caused a most desirable modification in the properties of the resulting polyester molding resins.
By way of illustration, poly(neopentyl-adipate), poly(l,6 - hexylene neopentyl - adipate - isophthalate), poly(l,6 - hexylene - (0.7)adipate (0.3)isophthalate); poly(l,6 - hexylene - (0.5)adipate - (0.5)isophthalate) and poly(l,6 - hexylene - (0.7) - azelate - (0.3)isophthalate), each having a hydroxyl number in the range of 32 to 38, corresponding to a number average molecular weight of 3000 to 3500, are used as the source of blocks. These polyesters are added, respectively, to a reactor after the ester interchange between 1 ,4-butanediol and dimethyl terephthalate is complete and any excess of butanediol has been removed by distillation under a mild vacuum.
After completion of the reaction and molding the block copolyesters, the moldings are improved in toughness and reduced in notch sensitivity as compared to bars molded from unmodified poly(l,4 - butylene terephthalate). There is insubstantial loss in flex modulus and strength. Even at only 100/, of the aliphatic/aromatic polyester content, the increase in impact strength is so marked that some of the samples cannot even be broken.
The effect on crystallization behavior is also noteworthy. The copolyester block components significantly reduce the crystallization rate of the molding resin.
This is desirable, since it allows longer time for the polymer melt to flow through thin walled sections of a mold before the cooling product solidifies.
In addition to their use in injection molding applications, the polyester coreactants have also been found to be beneficial in improving the properties of poly(l ,4-butylene terephthalate) resins used in other applications, such as profile extrusion, extrusion-and injection blow molding, thermo-forming, foam molding; in these cases small amounts of ester-forming branching agents may be added to enhance the melt elasticity properties of the products for easier processing.
The block copolyester products have also been converted to valuable modifications by adding reinforcing fillers, such as glass fibers and talc.
Surprisingly, the increased toughness of the block copolyesters compensates for the greater brittleness usually induced by the incorporation of such non-soluble additives and fillers.
Flory, U.S. 2,691,006, discloses various copolyesters and their preparation by several different procedures. The copolyesters of Glory are distinguishable from the copolyesters described herein because those therein do not have one copolyester block derived wholly from an aromatic diacid and another copolyester block that contains only an aliphatic dicarboxylic acid residue or a block that contains at least 10 mole 0/, of aliphatic units.
Waller and Keck, U.S. 3,446,778, also disclose a variety of block copolyesters.
However, these are also different from those of this invention. The blocks in the copolyesters of the '778 patent are linked together by an interlinking agent such as terephthaloyl-bis-N-caprolactam or include a poly-functional compound for producing a branched non-aromatic block. The copolyesters herein do not include an interlinking agent, e.g., diisocyanates, or a branching compound in the nonaromatic block; they are joined block to block by a polyester linkage.
Sumoto, Imanaka and Shirai, Japanese Patent Publication 49-99150, datedSeptember 19, 1974, disclose flame retardant compositions comprising block copolyesters which, however, are different from those herein. The methods of preparation in Sumoto et al will give high randomization of the blocks because all ingredients, dimethyl ester of aromatic dicarboxylic acid, diol and the polymer for producing "soft polymer segment" are mixed together and heated with a transesterification catalyst. In contrast, the copolyesters according to the present invention are not highly randomized because the coreactant is not added until the ester interchange has been completed and the excess butanediol has been removed.
This reaction is a transesterification between a poly(l,4-butylene terephthalate), prepolymer or polymer, and the coreactant polyester. The other methods inSumoto et al, Like Waller et al, give segmented copolyesters joined through linking compounds such as diisocyanates, and lactone monomers.
According to this invention, there are provided thermoplastic copolyesters which consist essentially of blocks derived from: (a) a terminally-reactive straight chain or branched poly(lQ-butylene terephthalate); and(b) (i) a terminally-reactive aromatic/aliphatic copolyester of a dicarboxylic acid selected from terephthalic acid, isophthalic acid, naphthalene dicarboxylic acids, phenyl indane dicarboxylic acid and compounds of the formula:
in which Xis alkylene or alkylidene of from 1 to 4 carbon atoms, carbonyl, sulfonyl, oxygen or a bond between the benzene rings and an aliphatic dicarboxylic acid having from 6 to 12 carbon atoms in the chain, with one or more straight or branched chain dihydric aliphatic or cycloaliphatic glycols having from 4 to 10 carbon atoms in the chain, said copolyester having at least 10 mole % and preferably, 35 mole V units being derived from the aliphatic dicarboxylic acid; or(ii) a terminally reactive aliphatic polyester of a straight chain aliphatic dicarboxylic acid having from 4 to 12 carbon atoms in the chain, and one or more straight or branched chain aliphatic glycols, said blocks being connected by interterminal linkages consisting essentially of ester linkages.
It is essential that the copolyester be prepared by the reaction of terminallyreactive poly(butylene terephthalate), preferably, low molecular weight, and a terminally-reactive copolyester or polyester as defined in paragraph (b), in the presence of a catalyst for transesterification, such as zinc acetate, manganese acetate or titanium esters. The terminal groups can comprise hydroxyl, carboxyl or carboalkoxy, including reactive derivatives thereof. The result of reaction between two terminally reactive groups, of course, must be an ester linkage. After initial mixing, polymerization is carried out under standard conditions, e.g., 220 to 280"C., in a high vacuum, e.g., 0.1 to 2 mm Hg, to form the block copolymer of minimum randomization in terms of distribution of chain segments.
The copolyester component (b) (i) is preferably prepared from terephthalic acid or isophthalic acid or a reactive derivative thereof and a glycol, which may be a straight or branched chain aliphatic or cycloaliphatic glycol. Illustratively, the glycol will be 1 ,butanediol; 1,5-pentanediol; 1,6-hexanediol; 1 ,9-nonanediol; 1,10- decanediol; neopentyl glycol; 1,4-cyclohexanediol; 1,4-cyclohexane dimethanol; or a mixture of any of the foregoing. Illustrative of suitable aliphatic dicarboxylic acids are suberic, sebacic, azelaic, and adipic acidsThe copolyesters of the polyester component (b) may be prepared by ester interchange in accordance with standard procedures. The polyesters (b) (i) are most preferably derived from an aliphatic glycol and a mixture of aromatic and aliphatic dibasic acids in which the mole ratio concentration of aromatic to aliphatic acids is at most 9:1, and is preferably between 1 to 9 and 9 to 1, with an especially preferred range being from 3 to 7 to 7 to 3.
The aliphatic polyesters designated component (b) (ii) will contain substantially stoichiometric amounts of the aliphatic diol and the aliphatic dicarboxylic acid, although hydroxy-containing terminal groups are preferred.
In addition to their ease of formation by well-known procedures, both the aromatic/aliphatic copolyesters (b) (i) and the aliphatic polyesters (b) (ii) are commerically available. One source for such materials is the RucoDivision/Hooker Chemical Company, Hicksville, New York, U.S.A. which designates its compounds as "Rucoflex".
The block copolyesters of this invention preferably comprise from 95 to 50 parts by weight of the segments of poly( 1 ,4-butylene terephthalate). The poly(l,4butylene terephthalate) blocks, before incorporation into the block copolyesters, will preferably have an intrinsic viscosity of above 0.1 dl./g. and preferably, between 0.1 and 0.5 dl./g., as measured in a 60:40 mixture of phenoVtetrachloroethane at 300 C. The balance, 5 to 50 parts by weight of the copolyester will comprise blocks of component (b).
As will be understood by those skilled in this art, the poly(l,4-butylene terephthalate) block (a) can be straight chain or branched, e.g., by use of a branching component, e.g., 0.05 to 3 mole %, based on terephthalate units, of a branching component which contains at least three ester-forming groups. This can be a polyol, e.g., pentaerythritol or trimethylolpropane, or a polybasic acid compound, e.g., trimethyl trimesate.
The block copolyesters may be employed as such in the fabrication of molded articles or they may be blended with other polymers, especially preferably poly(l,4butylene terephthalate) straight chain or branched (as described), and with stabilizers, reinforcing agents and/or flame retardant additives.
In one feature of the invention, the block copolyesters may be combined with high molecular weight poly(l,4-butylene terephthalate), i.e., having an intrinsic viscosity of at least 0.7 dl./g., as measured in a 60:40 mixture of phenol/tetrachloroethane at 300C. These compositions can vary broadly, but, preferably, will contain from 5 to 95 parts by weight of the block copolyester and from 95 to 5 parts by weight of the high molecular weight poly(l,4-butylene terephthalate), straight chain or branched.
Suitable reinforcing agents are well known but, illustratively, they may be metals, such as aluminum, iron or nickel particles, or non-metals, such as carbon filaments, silicates, such as acicular calcium silicate, asbestos, titanium dioxide, potassium titanate and titanate whiskers, wollastonite, glass flakes and fibres. It is also be to understand that unless the filler adds to the strength and stiffness of the composition, it is only a filler and not a reinforcing filler as contemplated herein.
Although it is only necessary to have at least a reinforcing amount of the reinforcement present, in general the reinforced compositions will comprise from 1 to 80V by weight of the total composition of the reinforcing agent.
In particular, the preferred reinforcing fillers are of glass, and it is usually preferred to employ fibrous glass filaments comprised of lime-aluminum borosilicate glass that is relatively soda free. This is known as "E" glass. However, other glasses are useful where electrical properties are not important, e.g., the low soda glass known as "C" glass. The filaments are made by standard processes, e.g., by steam or air blowing, flame blowing and mechanical pulling. The filament diameters range from 0.00012 to 0.00075 inch, but this is not critical to the present invention. Glass fibers may be surface coated in accordance with standard procedures to improve their reinforcing performances. In general, best properties will be obtained from reinforced compositions that contain from 20 to 30 percent by weight of the glass reinforced composition.
The length of glass filaments and whether or not they are bundled into fibers and the fibers bundled in turn to yarns, ropes or rovings, or woven into mats, are also not critical to the practice of the invention. In preparing the present compositions, it is convenient to use the filamentous glass in the form of chopped strands of from 1/8 inch to 1 inch long, preferably less than 1/4 inch long. In articles that are molded from the compositions of the invention, even shorter lengths will be encountered because, during compounding, considerable fragmentation will occur. This is desirable, however, because the best properties are exhibited by thermoplastic injection molded articles in which the filament lengths lie between 0.000005 inch and 0.12 (1/8 inch).
Compositions of this invention can be prepared by a number of procedures. In one way, the reinforcement, e.g., fillers or fibers, pigments, or stabilizers, are put into an extrusion compounder w th the resinous components to produce molding pellets. The additives are dispersed in a matrix of the resin in the process. In another procedure, the additive(s) and the resin are dry blended then either fluxed on a mill and comminuted, or they are extruded and chopped. The additives can also be mixed with the resin(s) and directly molded, e.g., by injection or transfer molding techniques.
In addition, compounding should be carried out to ensure that the residence time in the machine is short, the temperature is carefully controlled; the friction heat is utilized; and an intimate blend between the resin and the reinforcement and/or other additives is obtained.
Although it is not essential, best results are obtained if the ingreidients are precompounded, pelletized and then molded. Pre-compounding can be carried out in conventional equipment. For example, after carefully pre-drying the block copolyester, and polyester resins and the additives, e.g., reinforcing agent, e.g., under vacuum at 1000C. for 12 hours, a single screw extruder is fed with a dry blend of the ingredients, the screw employed having a long transition section to ensure proper melting. On the other hand, a twin screw extrusion machine, e.g., a 28 mmWerner Pfleiderer machine can be fed with resin and additives at the feed port and reinforcement downstream. In either case, a generally suitable machine temperature will be 450 to 4600 F.
The pre-compounded composition can be extruded and cut up into molding compounds such as conventional granules, or pellets, by standard techniques.
The composition can be molded in any equipment conventionally used for thermoplastic compositions.
The following examples illustrate the invention.
EXAMPLE 1Into a 500 ml., 3-neck flask is weighed 100 grams (0.5 moles) of a poly(lA- butylene terephthalate) prepolymer, containing residue of tetraoctyl titan ate transesterification catalyst, having an intrinsic viscosity of about 0.1 dl./g., as measured in a 60:40 mixture of phenoVtetrachloroethane at 300 C. After evacuating the flask and purging with nitrogen, the flask is submerged in an oil bath heated to 2350C. The agitator is turned on and stirring maintained at low speed while the prepolymer melts. Upon completion of the melting, 54 grams of poly(neopentyl-adipate) (number average molecular weight 3000) is added to the stirred melt while maintaining a nitrogen bleed. Since the addition of the poly(neopentyl-adipate) causes some solidification of the mass, a few minutes are spent re-melting the mixture. Aspirator vacuum is applied and the temperature is raised to 252 to 2550C. A vacuum of 12 to 13 mm is attained and a slow, steady distillation commenced. After about 20 minutes, full vacuum is applied via pump and maintained at 0.3 to 0.4 mm of mercury throughout the polycondensation.
Approximately one hour later, the vacuum is shut off and the system brought to equilibrium. The material is soft and elastic and adheres to aluminum foil tenaciously. The block copolymer consists of 34V poly(neopentyl-adipate) and 66V, polybutylene terephthalate, and has an intrinsic viscosity of 0.66 dl./g., as measured in a 60:40 mixture of phenoVtetrachloroethane at 30"C.
EXAMPLE 2The resin prepared in Example 1, after being placed in a container with dry ice overnight, is chopped in a Wiley mill. The ground material is dried in a vacuum desicator. Seventy grams of this material is tumble blended (paint shaker) with 630 grams of a finely divided poly(l,4-butylene terephthalate), having an intrinsic viscosity of about 1.0 dl./g., as measured in a 60:40 mixture of phenoVtetrachloroethane at 300 C., and 1.4 grams of Irganox 1093 ("Irganox" is aRegistered Trade Mark). The material is extruded on a 1 inch Wayne extruder to form an essentially clear melt. Test bars are injected molded at a 4700 F. melt temperature 750 lb. pressure and a 32 second cycle.
The test bars have the following physical properties:Notched Izod, ft.lbs/in. 1.24Heat Deflection Temp. "F. 264 psi 121198 psi 13266 psi 255Tensile strength at yield, psi 6,653Elongation at break, Vo 281Flexural strength, psi 9,678Flexural modulus, psi 288,000COMPARATIVE EXAMPLE AA control sample of unmodified poly(l,4-butylene terephthalate) is submitted for physical testing with the following results:Notched Izod Impact, ft.lbs./in. 0.8Heat Deflection Temp. "F. 264 psi 130198 psi n.d.
66 psi 310Tensile strength at yield psi 7,500Flexural strength, psi 13,000Flexural modulus, psi 350,000EXAMPLE 3A block copolyester is prepared as described in Example 1 except that only 20.5 grams of the poly(neopentyladipate) is employed. Seventy grams of this block copolyester is ground according to the procedure of Example 2 and blended with 630 grams of the poly(l,4-butylene terephthalate) employed in Example 2. The blend is extruded into test bars according to the procedure described in Example 2.
The test bars have the following physical properties:Notched Izod, ft.lbs./in. 1.23Tensile strength at yield, psi 7,422Elongation at break, % valuesranges from 46 to 346Heat Deflection Temp. "F. 264 psi 127198 psi 134132 psi 15166 psi 300Flexural strength, psi 11,420Flexural modulus, psi 347,500 EXAMPLE 4Into a 500 ml., 3-neck flask is weighed 110 grams (0.5 moles) of the poly(l,4butylene terephthalate) prepolymer employed in Example 1. After successive evacuations and nitrogen purges, the flask is immersed in an oil bath at 235"C.
After melting, 10.3 grams (0.48 mole) of poly(neopentyl-adipate) is added.
Aspirator vacuum of about 10 mm of mercury is commenced and the temperature is raised to 2550C. over a six-hour period. Fifteen minutes later, pump vacuum is applied to raise the vacuum to about 0.2 mm of mercury. The reaction is continued for one hour and after removal of vacuum, the polymer is removed according to the method of Example 1.
EXAMPLE 5A reactor is charged with 35.3 Ibs. of dimethyl terephthalate, a stoichiometric excess of 1,4-butanediol and 8.0 grams of tetraisopropyl titanate. The temperature is raised in stages to 2020 C. and the vacuum is increased to 1/3" Hg. After one hour and 25 minutes, the vacuum is removed and 4 Ibs. of poly(neopentyl-adipate) (molecular weight 3000) is added. The low molecular weight poly( 1 ,4-butylene terephthalate) is transferred to another reactor and polymerization is carried out at about 250"C. and at a pressure of about 0.2 mm of mercury. After two hours, the vacuum is released and the polymer is obtained in band form by hand and is chopped after it is cooled to room temperature. The block copolyester has the following properties:IV=0.81 as measured in a 60:40 mixture of phenoVtetrachloroethane at 300C.
Melting range 175 to 197"C.
Composition-9V poly(neopentyl-adipate)Notched Izod ft.lbs./in. 1.21Tensile strength, psi at yield 5,632Elongation, V 350Flexural strength, psi 7,900Flexural modulus 226,000EXAMPLES 67 The block copolyester prepared in Example 5 is blended with poly( 1,4- butylene terephthalate) and a reinforcing agent:Example (parts by weight) 6 7 poly( 1 ,4-butylene terephthalate)* 800 900block copolyester of poly(l,4butylene terephthalate) and poly(neopentyl-adipate) (Example 5) 200 100glass fibers 300 300stabilizer** 1.95 1.95*Example 2**Irganox 1093The compositions have the following molded properties:Example 6 7Notched Izod, ft.lbs./in. 1.45 1.53Tensile strength, psi at yield 14,050 14,130Elongation, V 8.2 7.9Flexural strength, psi 23,230 23,040Flexural modulus, psi 920,000 829,000EXAMPLE 8A low molecular weight poly(l,4-butylene terephthalate) (110 grams) having an intrinsic viscosity of about 0.1 dl./g., as measured in a 60:40 mixture of phenoVtetrachloroethane is placed in a 3-neck, 300 ml. flask; the flask is purged three times with nitrogen and dipped into a 2500C. oil bath. Upon melting, 33.17 grams of poly(l,6-hexylene-(0.5) adipate-(0.5) isophthalate), with an approximate number average molecular weight of 1600, is added and the aspirator is started and is run for 23 minutes before the pump is started. The reaction is run under full pump vacuum for 135 minutes at an average pressure of 0.2 mm and temperature of 250"C. A soft, milky white product (105.3 grams) is obtained having the following analysis: IV=0.71 dl./g. as measured in a 60:40 mixture of phenoVtetrachloroethane at300C.
Melting range 133 to 1640C.
Flexural strength, psi 1,700Flexural modulus, psi 38,270Tensile strength, psi at yield 2,930Elongation, V 386EXAMPLE 9The general procedure of Example 8 is followed in preparing a blockcopolyester of poly(l,4-butylene terephthalate) (110.04 grams) and poly(l,6hexylene-(0.5) adipate-(0.5) isophthalate) (33.3 grams) (number average molecular weight 3000). There is obtained 110.75 grams of a soft, creamy white product that has the following physical properties:Poly(l,6 - hexylene - (0.5)adipate - (0.5)isophthalate content 23V IV-0.91 dl./g. as measured in a 60:40 mixture of phenoVtetrachloroethane at 30cm.
Melting range 124 to 1620C.
Flexural strength, psi 1,430Flexural modulus, psi 30,520Tensile strength, psi at yield 2,630Elongation, V 436EXAMPLE 10Into a 3-neck, 300 ml. flask is placed 110 grams of the poly(l,4-butyleneterephthalate) employed in Example 9. This is melted at 2350C. (after nitrogen purging) and 33.2 grams of poly(l,4-butylene-adipate) (number average molecular weight 1600) is added. After complete melting, the aspirator vacuum is applied for about 20 minutes. Then full vacuum via pump is started, the temperature is raised to 2500C. and the reaction continued. A vacuum of 0.3 mm is attained for a short period but rises to 5 mm because of a leak. After finding the leak, 0.3 mm is restored and vacuum is maintained for about three hours. An off white material is collected which has the following physical properties: Poly(l,butylene adipate) content 23% IV=0.90 dl./g. as measured in a 60:40 mixture of phenoVtetrachloroethane at 30"C.
Melting range 165 to 1880C.
Flexural strength, psi 2,440Flexural modulus, psi 56,080Tensile strength, psi at yield 3,530Elongation, V 348EXAMPLE 11Into a 3 neck flask is weighed 110 grams of poly(l,4-butylene terephthalate) (IV=0.1 dl./g., as measured in a 60:40 mixture of phenoVtetrachloroethane at 300C.). After purging with nitrogen, and melting the polymer at 2350C., 34 grams of poly(ethylene-co-l,4-butylene-adipate) (number average molecular weight 3000) is added; and vacuum is applied as the temperature is raised to 2500C. After about two hours, a flesh-colored polymer is recovered that has the following properties: Poly(ethylene-co- 1 ,4-butylene adipate) content 23.6V IV=0.92 dl./g. as measured in a 60:40 mixture of phenoVtetrachloroethane atInar, Melting range 138 to 171"C.
Flexural strength, psi 1,980Flexural modulus, psi 43,540Tensile strength, psi at yield 2,900psi at break 3,400Elongation, V 410EXAMPLE 12Into a 3-neck flask is weighed 110 grams of poly(l ,4-butylene terephthalate) (IV of about 0.1 dl./g. as measured in a 60:40 mixture of phenoVtetrachloroethane at 30 C.). After purging with vacuum and N2 and melting at 2350C. with stirring, 32.9 grams of a copolyester of adipic acid, ethylene glycol and 1,4-butanediol is added. Stirring is continued until melting is complete. Then the vacuum aspirator is applied and the temperature is raised to 2500 C. over a 50-minute period. Twenty minutes later, the vacuum pump is turned on and full vacuum (0.3 mm Hg) is maintained for one hour and 25 minutes. The polymer has an off white color having the following properties:Content of copolyester of adipic acid, ethylene glycol and 1,4-butanediol 23V IV=0.81 dl./g. as measured in a 60:40 mixture of phenoVtetrachloroethane at 30"C.
Melting range 145 to 174 C.
Flexural strength, psi 2,085Flexural modulus, psi 47,475Tensile strength, psi at yield 3,170Elongation, V 30EXAMPLE 13A block copolyester of poly(l ,4-butylene terephthalate) IV=0.1 dl./g. as measured in a 60:40 mixture of phenoVtetrachloroethane at 300 C. This polymer is molded into flex and tensile bars, HDT bars and plaques using the Van Dorn machine. Molding conditions and properties are as follows:Melt. temperature, OF. 360" Nozzle temperature, OF. 3500Front zone, OF. 3400Center zone, OF. 3400Rear zone, "F. 3400Mold temperature, OF. 1000Cycle timeInjection, sec. 15Molded closed, sec. 35Mold open, sec. 2Pressure, psi 600Tensile strength, psi at yield 2,466psi at break 5,227Flexural strength, psi 2,994Flexural modulus, psi 72,445Elongation, V 640Notched Izod, ft.lbsSin. no breaksGardner Impact 120 in Ibs.
(Shatters)Heat Deflection Temp. OF. 66 psi 130264 psi 93EXAMPLES 15-19 The following dry ingredients are placed in a stainless steel can and mixed on a paint shaker for four to five minutes. This is followed by extrusion of a 1" Wayne extruder:Example (parts by weight) 15 16 17 18 19 poly( 1 ,4butyleneterephthalate) (MW 6000) 1,350 1,200 1,050 750 375block copolyester ofpoly( 1 ,4-butylene terephthalate) and poly(neopentyl-adipate)(Example 14) 150 300 450 750 1,125 stabilize? 2.25 2.25 2.25 2.25 2.25stabilizer** 0.75 0.75 0.75 0.75 0.75These compositions have the following molded properties:Example 15 16 17 18 19Tensile strength,psi at yield 7,514 6,895 6,238 5,230 4,890psi at break 6,720 6,126 5,384 4,582- - 6,541Elongation, V 300 274 289 375 270Flexural strength,psi 11,850 10,750 9,250 - 4,650Notched Izod, ft.
IbsJin. 0.78 0.90 0.92 0.93 1.6Heat DeflectionTemp. OF.
66 psi 290 290 233 222 - 264 psi 125 117 115 107 - *Irganox 1093**Ferro 904 ("Ferro" is a Registered Trade Mark) EXAMPLES 2022 The listed resins and stabilizers are blended by mixing on a paint shaker forfour to five minutes. The glass fibers are mixed in by hand and the batches extrudedon a 1" Wayne extruder:Example (parts by weight) 20 21 22poly( 1 4-butyleneterephthalate) (MV6000) 945 840 735block copolyester of poly( 1 ,4-butylene terephthalate) and poly(neopentyl-adipate)(Example 14) 105 210 315glass fibers 450 450 450stabilizer* 2.25 2.25 2.25stabilizer** 0.75 0.75 0.75These compositions have the following molded properties:Example 20 21 22Tensile break, psi 15,700 14,900 14,200Elongation, V 8.6 8.0 7.6 Flexural strength, psi 24,166 23,615 22,800Flexural modulus, psi 930,000 1,024,000 913,000Notched Izod, ft.
Ibs./in. 2.0 2.2 2.1Heat DeflectionTemp. F.
66 psi 430 425 425264 psi 380 365 365*Irganox r093 **Ferro 904EXAMPLE 23A 10-gallon polyesterification reactor is charged with 30 Ibs. of dimethylterephthalate, 24 Ibs. of 1,4-butanediol and 11 grams of tetra(2-ethylhexyl)titanate.
The mixture is gradually heated with stirring to 220 to 2250C. while methanoldistills off (approximately I 1/2 hours). Subsequently, a vacuum is applied to the vessel and the excess butandiol is distilled (approximately 1 hour required). Then1.54 Ibs. of poly(neopentyl-adipate), MW 32003500, is added. The temperature is raised to 250 to 2550C. and the vacuum increased to 0.2 to 0.4 mm Hg until the product reaches a melt viscosity of 6100 poises*. The vacuum is released with nitrogen and the product cast onto a chilled roll through a slide valve in the bottom of the reactor. The resulting band is granulated in a dicer into approximately 1/8" cubes. The cubes are extruded, chopped and molded into test bars that have the following physical properties:Gardner Impact in./lbs. 300Notched Izod, ft.lbs./in. 1.0Tensile strength, 103 psi 7.3Tensile elongation, V 304Flexural strength, 103 psi 12.1Flexural modulus, 103 psi 329Deflection Temp., "F 264 psi 127Crystallization rates, 200"F. time to initialcrystallization, Ti (Secs.) 2.0time to 50V crystallization (Secs.) 0.6Tm AHf Tc AHc DSC Data "C. caVg. "C. cal/g.
215 7.0 163 10.8*MV=melt viscosity in poises at 2500 C. using melt index procedure with21,600 g weight and .042x.615" orifice.
EXAMPLES 2" 28 Using the same procedure as Example 23, the following block copolyesters are prepared with poly(l,4-butylene terephthalate) blocks and blocks comprising the listed copolyesters and using 11 grams of tetra(2-ethylhexyl)-titanate as a transesterification catalyst:Example Components Weight (Ibs.) 24 dimethyl terephthalate 27 1 ,4-butanediol 25poly(1,6-hexylene-(0.7) azelate (0.3) isophthalate) 325 dimethyl terephthalate 27 1 ,4-butanediol 25polyneopentyl-adipate 326 dimethyl terephthalate 27 1 ,4-butanediol 25 poiy(l ,6-hexylene-(0.5) adipate (0.5) isophthalate) 327 dimethyl terephthalate 271,4-butanediol 25poly(l ,6-hexylene-(0.7) adipate(0.3) isophthalate) 328 dimethyl terephthalate 27 1 ,4-butanediol 25 poly( l ,6-hexylene-co-neopentyl- adipate-co-isophthalate) 3These copolyesters are found to have the following physical and moldedproperties:Example 24 25 26 27 28Melt viscosity(poise) 7,400 6,500 6,600 6,900 4,900Gardner impact in.Abs. 350 250 439 439 350p/t/s** 7/lOp 6/8p 5/8p 3/4p3/lOt 7/8p 2/8s 3/8t 1/4sNotched Izod Impact, ft.lbs./in. 3/5NB*** 3.4 2.8 2.3 4.1Tensile strength,103 psi 5.6 5.3 5.8 5.6 5.7Tensile elongation, V 442 537 478 495 494Flexural strength, 103 psi 9.5 10.6 11.3 10.7 11.1Flexural modulus, 103 psi 240 269 285 280 282Deflection Temp.
OF. at 264 psi 124 108 109 108 113Crystallizationrates, 200"F. (Secs.)Ti 2.7 4.9 2.8 3.0 3.2TV2 1.2 3.5 1.2 0.9 1.4 DSC Data, Tm/"C. 205 187 202 199 199 AHf/caVg 6.2 5.1 5.7 5.5 5.7 TC/OC 147 130 141 137 136 AHc/caVg 9.1 8.4 8.3 8.2 8.9*3 out of 5 test samples did not break. The remaining 2 samples had an averageimpact strength of 5.8 ft.lbs./in.
**p=pass test; t=sample failed by tearing; s=sample failed by shattering ***NB-no break EXAMPLE 29Into a reactor are charged 35.3 Ibs. of dimethyl terephthalate, 32.6 Ibs. of 1,4butanediol, 15.0 grams of tetraoctyl titanate and 24.0 grams of pentaerythritol as a polyol branching agent. The vessel contents are heated at 2100C. during 55 minutes under vacuum and maintained until methanol and excess diol have finished distilling, about one hour and 45 minutes being required. Then 11.5 Ibs. of poly(neopentyl-adipate) is added and the mixture is transferred to a high vacuum kettle. Under full vacuum (NO.22 mm Hg), the contents are heated at 250"C. for an additional two hours, then removed from the reactor. After cooling, the polymer has an intrinsic viscosity of 1.11 and the weight of the contained poly(neopentyladipate) blocks is about l8V.
Molded properties on the block copolyester are:Tensile strength, psi 5,052Elongation, V 585Flexural strength, psi 1,249Flexural modulus, psi 31,522EXAMPLES 3032 The branched block copolyester of Example 29 is extrusion blended into compositions with poly( 1 ,4-butylene terephthalate) as follows:Example (parts by weight) 30 31 32 poly( 1 ,4-butylene terephthalate) 900 750 500Copolyester of Example 29 100 250 500Stabilizer, Irganox 1093 1.5 1.5 1.5Stabilizer, Ferro 904 0.4 0.4 0.4PropertiesTensile strength, psi 7,056 6,127 4,463Elongation, V 326 313 274Flexural strength, psi 10,190 8,883 5,094Flexural modulus, psi 341,333 281,423 14,317Impact strength, ft.lbs./in. Notch 0.97 1.04 3.46WHAT WE CLAIM IS:1. A thermoplastic copolyester which comprises blocks derived from:(a) a terminally-reactive straight chain or branched poly( 1 ,4-butylene terephthalate); and(b) (i) a terminally-reactive aromatic/aliphatic copolyester of an aliphatic dicarboxylic acid having from 6 to 12 carbon atoms in the chain and an aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid, naphthalenedicarboxylic acids, phenyl indane dicarboxylic acid and compounds of the formula:
in which X is alkylene or alkylidene having from 1 to 4 carbon atoms, carbonyl,sulfonyl, oxygen or abond between the benzene rings, and one or more straight orbranched chain dihydric aliphatic or cycloaliphatic glycols having from 4 to 10carbon atoms in the chain, said copolyester having at least 10 mole V of units beingderived from the aliphatic dicarboxylic acid; or(ii) a terminally-reactive aliphatic polyester of a straight chain aliphaticdicarboxylic acid having from 4 to 12 carbon atoms in the chain and one or more straight or branched chain aliphatic glycols, said blocks being connected by interterminal linkages consisting essentially of ester linkages.
2. A thermoplastic copolyester as claimed in Claim 1 wherein block (a) isbranched.
3. A thermoplastic copolyester as claimed in Claim 1 or 2 wherein block (a)
**WARNING** end of DESC field may overlap start of CLMS **.