IL35167A - Polyalkylene terephthalate molding resin and process for making the same - Google Patents

Description

RESIN AND PROCESS FOR THE SAME This relates to a resin d to method of producing The invention is directed to improved molding resin comprising an intimate blend of a reinforcing filler and a polybutylene terep e or a polypropylene The resin of this invention has significant processing and property advantages over an e filled molding Polyethylene terephthalate polymer containing reinforcing fillers have been used as molding resins for various end The use of filled polyethylene terephthalate polymer for molding purposes has processing disadvantages in requiring high processing high mold long cycle times in the mold and usually requires a nucleating or other additive to provide an adequate polymer flow in the The preparation of polyethylene terep late polymers as well as polypropylene terep and polybutylene polymers are described in entitled Polymeric Linear Tereph Polyethylene tereph thalie have been use for film products and molding It area of their outstanding physical properties to the exclusion of the other linear terephthalic esters especially polypropylene terep thal te and terephthalate It has now been discovered that molding resins are provided by the intimate blending of reinforcing fillers with polypropylene terephthalate or The improved molding resins of this invention have been found to require lover processing lower mold shorter cycle time and no nucleating agent when compared with equivalent filled polyethylene terep the excellent processability of the molding resins of this invention is accorapanied by a balance of properties it even more desirable than polyethylene For glass filled polybutylene terephthalate resin has almost identical strength compared to the equivalent glass filled polyethylene phthalate but substantially higher lower water better creep properties and desirable The molding resins of this invention the processing problems with the equivalent filled polyethylene terephthalate molding resin as well viding a balance of properties w ch are significantly improved over those of polyethylene The base of the molding resins of this invention is a polyalkylene terephthalate polymer selected from the group consisting of polypropylene terephthalate and the reaction product of or a ester of terephthalic acid dimethyl and glycols having 3 and 4 carbon Suitable include trime hylene butylene glycol and the In the production of the polymers of this invention polypropylene or polybutylene the appropriate bis terephthalate is produced as the The monomeric bis terephthalate can be prepared by at least tvro different In one the dialkyl ester of terephthalic acid in the alkyl radicals can contain from 1 to 7 carbon atoms can generally be reacted with about two molecular proportions of the glycols It is preferred to use higher proportions of the in excess of two molecular proportions of the glycol per molecular proportion of the terephthalate since by using such the initial transesterification caused to take place more rapidly and The reaction for the transes erification i3 conducted conditions of elevated temperatures and subat or super eric the desired tures of the reaction can from about the boiling temperature of the reaction mixture to as high as if After the polymer base is the reinforcing types of If the reinforcing fillers can be blended with the monomers in polymerization reaction long as the polymerization reaction is not The types of fillers which can be used include among others glass fibers or continuous asbestos cellulosic cotton fabric synthetic metallic powders and the The amount of reinforcing filler can range from about 2 to about 80 weight per preferably from about 5 to about 60 weight per cent based on the total molding Other additives for appearance and property improvements can be incorporated into the molding resins of this invention such as hardeners and the The following examples will serve to illustrate the invention without limiting the EXAMPLE I Fifteen pounds of polybutylene terephthalate having an intrinsic viscosity of was added to pounds of glass tumble blended for 1 minute and then extrusion blended by force feeding through a one inch single screw extruder with a strand The temperatures of the extruder and die were set at 510 and barrel to The strands were ground in a milling type mixer to pass through a large screen mesh or Polypropylene terephthalate was blended with glass fibers and extruded in a similar For comparative purposes polyethylene terephthalate facilitate the crystallization of polyethylene terephthalat in the weight per cent of talc was added to the Processing of the polyethylene terephthalate mold ing resin was exactly identical to the polybutylene thalate molding resin above except for slightly higher temperature requirements in the extrusion blending The above molding resins were molded into test specimens and tested for the following properties as described in the Tables TABLE I PROPERTIES OF GLASS FILLED POLYBUTYLENE GLASS FILLED POLYETHYLENE TEREPH Material Polyethylene Glass Content Processing Temperature 260 Cycle Time 52 Mold Temperature Base Molded Bar Notched Izod Tensile Impact 28 Deflection 264 psi 432 Tensile Strength Strength Flexural Modulus x Material Polyethylene Terephthalate 24 Water saturation Colo Hardness Rockwell MAT Gla Pro Cyc Not Hea Tensile Strength Strength Flexural ate resins have significant over the equivalent glass Compared to polyethylene polypropylene and polybutylene terephthalate can 5 be processed at lower at a significantly lower cycle and a lower mold It has significantly high notched and tensile less shrinkage and lower water All of these improved properties of the glass filled polypropylene and polybutylene terephthalate resins are highly 10 desirable and significant when compared to equivalent glass polyethylene terephthalate EXAMPLES similar manner as in Example polybutylene was blended with glass fibers in various 15 The properties of molded bars were obtained as described in III 0 20 30 Specific G y Intrinsic Viscosity Tensile 8300 Tensile 13 Flexural psi Flexural psi x 105 x 105 x 10 Tensile psi 8100 Tensile 13 12 Impact psi a no ched b Rockwell M 88 83 Distortion a 66 psi b 264 psi 73 209 213 a b of which variations by those skilled in art the scope of the following without departing from the spirit insufficientOCRQuality

Claims (10)

CLAIMS: ■WHAT IS CLAIMED IS

1. A molding resin comprising an intimaite blend of from about 2 to about 80 weight per cent of the total composition of a reinforcing filler and from about 20 to about 98 weight. per P cent of the total composition of a polyalkylene terephthalate polymer .having an intrinsic viscosity in the range from about 0.2 to about 1.2 wherein said polyalkylene terephthalate is selected from the group consisting of polypropylene terephthalate and polybutylene terephthalate.

2. The composition of claim 1 wherein the intrinsic viscosity of said polyalkylene terephthalate ranges from about 0.5 to about 1.0..

3. The composition of claim 2 wherein the reinforcing filler is present in amounts ranging from 5 to 60 weight per cent of the total resin.

4. The composition of claim 3 wherein the polyalkylene terephthalate is polybutylene terephthalate.

5. The composition of claim 4 wherein the reinforcing filler is glass fiber.

6. A method for producing an improved resin comprising intimately blending from about 2 to about 80 weight per cent of the total composition of a reinforcing filler with from about 20 to about 98 weight per cent of the total composition of a polyalkylene terephthalate polymer having an intrinsic viscosity in the range from about 0.2 to about 1.2 wherein said polyalkylene terephthalate is selected from the group consisting of polypropylene terephthalate and polybutylene terephthalate.

7. The process of claim 6 wherein the intrinsic viscosity ranges from about 0.5 to about 1.0.

8. process of claim 7 wherein the reinforcing filler is present in amounts ranging from about 5 to about 60 weight percent of the total resin.

9. The process of claim 8 wherein the polyalkylene terephthalate is polybutylene terephthalate.

10. The process of claim 9 wherein the reinforcing filler is glass fiber. Attorkey for Applicants