Title of Invention

AN ENGINEERING PLASTIC COMPOSITION AND METHOD FOR PREPARING SUCH COMPOSITIONS

Abstract

The present invention provides an engineering plastic resin composition comprising Polyethylene terephthalate (PET) and polytrimethylene terephthalate (PTT) random copolymer/alloy/blend. The present invention also provides a process of modifying the PET/PTT engineering plastic resin with nucleating agents, glass fibers, impact modifiers and/or flame retardants. PET/PTT of this invention is more cost effective and is better in comparison with Nylon and PBT with the same productivity of molded components.

Full Text

THE PATENTS ACT 1970 (39 of 1970) & THE PATENTS RULES, 2003 PROVISIONAL SPECIFICATION (See section 10 and rule 13) POLYETHYLENE TEREPHTHALATE AND POLYTRIMETHYLENE TEREPHTHALATE RANDOM COPOLYMER / ALLOY / BLEND AS ENGINEERING PLASTICS Futura Polyesters Ltd An Indian Company Of Paragon Condominium, 3rd Floor, Opp Century Mills, Behind Mahindra Towers, Pandurang Budhakar Marg, Mumbai - 400 013 The following specification describes the invention. Polyethylene Terephthalate and Polytrimethylene Terephthalate Random Copolymer / Alloy / Blend as Engineering Plastics Field of the Invention The present invention relates to Engineering thermoplastics with improved physical, electrical, thermal and mechanical properties and a preparation thereof. The said engineering thermoplastic compound envisaged in accordance with this invention is a random copolymer/Blend/Alloy of Polyethylene Terephthalate (PET) and Polytrimethylene Terephthalate (PTT) which can be simply and economically produced for applications in Automotive, Electrical, Electronics and Consumer goods by Injection Molding, Compression Molding, Extrusion Molding and other suitable molding methods. Background of the Invention Engineering plastics are plastics that retain their dimensional stability at extreme conditions of temperature and pressure. Engineering thermoplastics are high performance materials that in many cases have replaced metals and offer exciting design and performance characteristics. Thermoplastics offer many advantages over traditional materials, including: low density; low energy for manufacture; low processing costs; and the ability to make complex shapes relatively easily. Engineering thermoplastic polyesters are performance polymers. Engineering Polyesters find applications in areas like Transportation, Automotive, Electrical / Electronic Appliances, Industrial and consumer goods. Many engineering thermoplastics are commercially available for variety of applications and include materials like ABS, polycarbonates, polyamides, polyesters, polysulfones, polyacrylates, polyimides and polyimidazoles. Engineering applications require a balance between cost and performance. Mechanical, thermal, electrical, and other physical properties determine which polymer will be selected. But, in performance polymer applications, the cost / performance balance is shifted toward performance. Since most of the polymers are aimed at Speciality lower volume uses, prices for most of these materials will remain high. PET, PTT, PBT (Polybutylene Terephthalate) and PEN (Poly ethylene Naphthalate) compete with other semi crystalline polymers for engineering thermoplastics, films and fiber markets. PET, introduced as an engineering thermoplastic in 1966, shows high strength, stiffness, dimensional stability, and chemical and heat resistance, and has good electrical properties but has the disadvantages of slow crystallization, lower Impact strength and higher warpage. Slow crystallization increases the molding cycle time and there by decreasing the productivity in molding processes. PBT has been an engineering polymer since 1974; PBT shows a high mechanical strength, a high heat deflection temperature, low moisture absorption, good dimensional stability, low creep, and excellent electrical properties. PBT also exhibits solvent resistance and is unaffected by water, weak acids and bases and organic solvents. PTT has been recently introduced commercially by Shell chemicals under the trade name Corterra. The properties of PTT are intermediate to those of PET and PBT. Additionally PTT gives higher crystallization rate than PET and better Surface properties and Gloss. Crystallization rate is an important parameter for the processing of semi crystalline polymers. PET and PEN Crystallize slowly in the absence of nucleating agents. PBT and PTT are fast crystallizing polymers. This invention envisages a PET-PTT compound as a random copolymer/Blend/Alloy for use as engineering plastics with excellent processing characteristics and high strength and rigidity for a broad range of applications. Typically properties in which they differentiate themselves from other engineering plastics are: • Excellent electrical properties • Excellent resistance to chemical attack and high environmental stress crack resistance, in particular in comparison to polycarbonates and PET - PBT blends • Very good heat and heat ageing resistance • Easy processability • Low Moisture absorption • Higher surface properties and Gloss . Higher stiffness better than PET,PBT To top this all, the engineering thermoplastic of this current invention viz. a compound of PET and PTT is more cost effective and gives better value in comparison with PET and PBT with the same productivity. Prior art European Pat. No. 1115926 reports threads made of polymer blend fibers or filaments based on PET, PBT and PTT. The PTT ranges from 5-95% in the PET-PTT blended fibers or filaments. US 6576340 discloses an acid dyeable polyester composition comprising polyester and / or copolyester of Polyethylene Terephthalate, Polytrimethylene Terephthalate, and polytetramethylene Terephthalate and secondary amine or secondary amine salt in an amount effective to promote acid-dyeability. US 2002127939 deals with bicomponent melt blown nonwovens of PTT with polypropylene, polyethylene, polyethylene Terephthalate, Polybutylene Terephthalate, polyamide and polylactide; extruded and spun together. The weight ratio of PTT to other component ranges from 1:99 to 99:1. US 6919131 disclose an elastic interlaced-textured yarn produced by interlacing the PET/PTT polyester. US 2005048301 describe heat shrinkable polyester film obtained by melt extruding PTT, PET and neopentyl glycol. US 2005163679 discusses a method for producing high molecular weight polyester such as PET, PBT, PEN, PTT and / or polyester of other Dicarboxylic acids and diols, including copolymers. US 2006008644 also reports about bicomponent fibers spun in a ratio of about 55/45 and 75/25 mixture of PET/PTT by weight. A Thesis on co-crystallization of the PET/PTT copolyester was studied using DSC and WAXD by Chi-Yun Ko in the year 2003, titled 'Non-isothermal Crystallization Kinetics, Multiple Melting Behaviors and Crystal Structure Simulation of Poly[(ethylene)-co-(Trimethylene Terephthalate)] s'. A study on PET and PTT in the amorphous state miscible in all the blend compositions has appeared in the Journal of Polymer Science Part B: Polymer Physics, Vol. 42, 676-686(2004) under the title 'Thermal, Crystallization, Mechanical, and Rheological Characteristics of poly (Trimethylene Terephthalate)/poly (ethylene Terephthalate) blends'. It can be seen from the prior art that though blends of PET and PTT are known for a variety of applications like fiber, high shrinkage film, nonwovens etc., its application as an engineering thermoplastic with improved physical, electrical, thermal and mechanical properties and as a substitute for PBT is not known. Also the engineering plastic composition of the present invention results in molded articles with high gloss and low mold shrinkage when compared to PBT. Objectives of the Invention The main object of this invention is to provide a process for making random copolyester/Blend/Alloy of PET-PTT of loading ranging from 12,15,20,30 and 40% of the minor component with Additives for various engineering thermoplastic applications. Another object of this invention is to provide engineering thermoplastics with improved physical, electrical, thermal optical and mechanical properties in comparison with PBT. One more object of the invention is to add appropriate nucleating agents to the PET-PTT random copolyester/blend/alloy to improve the crystallization rate thereby improving the cycle time in the molding process and make the molded product cost effective in comparison with PBT. One more object of the invention is to make the PET-PTT engineering plastics random copolyester/blend/alloy as glass Fiber, glass beads / minerals like Talc, Calcium Carbonate, Feldspar, wollestonite, Mica, Barium Sulphate and similar minerals filled material from 0 to 40% loading for performance products used in automotive, electrical and electronic and other engineering applications. Another object of the invention is to increase the impact strength of the PET-PTT random copolyester/blend/alloy by the addition of suitable impact modifiers namely, Ethylene-Acrylic ester-Glycidyl Methacrylate Lotader), EVA, EBA, EMA, EEHA, Ethylene - Vinyl Acetate -Maleic(Anhydride, Ethylene - Acrylic Ester - Maleic Anhydride, Maleic Anhydride grafted LLDPE, Maleic Anhydride grafted PP, Maleic Anhydride grafted EVA, MA, PS and ABS as a substitute for Polycarbonate. Yet another object is to blend the PET-PTT random copolyester/blend/alloy with Polycarbonate to a loading from 0 to 40% to achieve better impact strength and chemical and stain resistance in the new blend. One more object of the invention is to mix Polyethylene Naphthalate (PEN) polymer from 0 to 30% loading with the PET-PTT random copolyester/blend/alloy to improve U.V light stability, thermal, mechanical and chemical resistance for specialized molding applications. One more objective of the invention is to mix hollow glass spherical beads from 0 to 40% with PET-PTT random copolyester/blend/alloy to reduce the specific gravity of the resultant polymer comparable to Nylon. Experiments were conducted in different methods each adopting various levels of monomer, additive and polymer loading. Example 1: The following is a typical case and other proportions of PET and PTT are possible as per application requirement. PTA and MEG are taken in an esterification reactor in the ratio of 1:1.5. To this 30 ppm of Cobalt as Cobalt Acetate, 250 ppm of Antimony as Antimony Trioxide, 2.1 ppm of RT and 1.5 ppm of BT as Blue and Red toners to improve color, are added. Further NU004 (sodium benzoate based product) 200 ppm and Nyacol (30% wt of silica in EG solution) 4500 ppm are also added as nucleating agents. The esterification is carried out at 240 - 265 deg C for a period of 260 min. At the end of esterification reaction Tetraethyl phosphonoacetate (30 ppm as P) is added to melt. The temperature is increased from 260-290 deg C under vacuum for a period of 220 min. After the required end speed is reached, 3% of calcium carbonate as an additive for property enhancement, 12, 15, 20, 30 and 40 % of PTT chips respectively and 1500 ppm of Aclyn 285 (Ethylene-Acrylic acid sodium ionomer) are added to the melt with a time interval of 3 minutes. The system is again brought under vacuum and held for 20 minutes for the reaction to complete and the molten amorphous polymer is taken out as strands and cut into chips. Example 2: PET, PTT chips were first pre dried in an Oven for 4 hours at 120 deg C and premixed in a Dry blender to produce PET/PTT preblends of 12,15, 20, 30 and 40% w/w of PTT respectively. Preblends were mixed with 30% w/w of Glass fiber and suitable additives separately to have glass filled materials. Further preblends were mixed with Impact Modifiers and suitable additives to obtain Impact modified materials. The preblends are then melt mixed in a Berstorff co rotating Twin Screw Extruder of L: D ratio 32:1 and Dia 40 mm with a speed of 70 kg/hr and at a temperature of 275 deg C. The extrudate was cooled in water bath and pelletized in strand Pelletizer. The final chips were collected and dried in an oven at 120 for 4 hours to remove moisture. The resultant chips were subjected to Thermal analysis in DSC to study Glass transition temperature, Crystallization temperature, Melting temperature and Heat of fusion. Further the chips were used to make specimen by Injection molding process to study Tensile strength, elongation, Impact strength, Flexural Strength and mold shrinkage. Example 3: 1:1.5 molar ratio of PTA and MEG are taken in esterification vessel. To this 12, 15, 20, 30, and 40% wt of PDO is added respectively along with 30 ppm of cobalt acetate (as Co), 1.5 ppm of RT and 1 ppm of BT as Color toners. To this mixture 2500 ppm Nyacol and 200 ppm of NU004 are added as nucleating agents. The esterification is carried out at 240-265 deg C for a period of 260 min. After esterification, 30 ppm of TEPA (as P), 10 ppm of tetra-n-butyl titanate and 30 ppm of antimony trioxide (as Sb) are added. The temperature is increased from 265-280 deg C under a vacuum for a period of 265 min. After the required end speed is reached, 2000 ppm of Aclyn 285 is added to the melt. The system is again brought under vacuum and held for 25 min for the reaction to take place and the molten amorphous polymer is taken out as strands and cut into chips. Example 4: PTA and MEG are taken in a ratio of 1:1.15. To this mixture 10% wt of NDC, 10 ppm of cobalt acetate (as Co), 130 ppm of antimony trioxide (as Sb), 25 ppm of Germanium dioxide, 100 ppm of Manganese 2- Acetate 4 -Hydrate and 1.5 ppm of RT and 1 ppm of BT as Color toners are added. The esterification is carried out at 240- 265 deg C for a period of 255 min. After esterification TEPA (10 ppm as P) and Tungsten trioxide (10 ppm) are added with a time interval of 10 min. The temperature is increased from 265-280 deg C under vacuum for a period of 133 min. After the required end speed is reached the molten amorphous polymer is taken out as strands and cut into chips. Table-l: Important characteristics of the PET-PTT-3% CaC03 random amorphous copolymer/blend/alloy in comparison with amorphous PET, PTT and PBT polymer. Description IV dL/g Carboxylnumbermeq/kg DEGwt% L* CIE a* CIE b* CIE Tg °C Tm °C Teh °C Specific Gravity g/cm3 PET PTT 1002 - 0.515 20 1.39 79.7 -2.4 -6.2 78.5 252.6 141.2 1.340 88 12 0.645 27 0.94 65.8 -2.6 -1.1 74.5 235.1 129.2 1.339 85 15 0.650 22 1.0 65.8 -1.6 -5.4 71.9 233.9 118.6 1.338 80 20 0.651 32 1.0 66.4 -2.8 0.02 70 224.5 118.6 1.335 70 30 0.648 26 1.1 66.5 -2.3 0.02 68.5 223.2 117.9 1.332 60 40 0.655 28 1.1 66.3 -2.9 0.03 67.9 215.2 120.3 1.330 - 1002 0.834 19 3.1 75.8 -5.1 0.8 44.9 225.9 71.4 1.330 PBT2 0.794 15 0.26 65.4 -3.4 0.70 25-40' 223.5 1.325 PTT +12% PDO2 0.580 41 0.78 65.2 -3.8 8.4 75.0 232.7 117.5 PETN2 0.604 18 - 60.0 0.2 -4.1 81.4 232.8 168.9 - 1 This data is available from polymer literature. 2without3%CaC03 Table-2:Mechanical properties and Moldability factor for PET-PTT-3% CaC03 random copolymer/blend/alloy in comparison with PET, PTT and PBT polymer. Description TensilestrengthMPa TensilemodulusMPa %Elong ation at break IzodimpactJ/m Flexural Strength MPa Flexural modulus MPa Mould Shrinkage% PET PTT 1001 - 45 1367 33 42 86 2462 3.0 88 12 55 1352 40 56 83 2360 1.9 85 15 62 1510 41 67 90 2571 1.9 80 20 59 1594 37 65 98 27956 1.8 70 30 55 1442 38 52 83 2354 2 60 40 54 1609 34 51 80 2294 2.5 - 1001 54 1806 30 55 86 2455 1.9 100% PBT1 52 1341 40 48 76 2278 2.8 1 without 3% CaC03 Table 3: Glass filled grades of the PET-PTT-3% CaCO3-30% Glass fiber random copolymer/blend/alloy in comparison with PET, PTT and PBT polymer. Description TensilestrengthMPa TensilemodulusMPa %Elong ation at break IzodimpactJ/m Flexural Strength MPa Flexural modulus MPa PET PTT 100' - 158 9 2.0 74 186 9.6 88 12 160 10 2.60 96 200 9.8 85 15 161 11 2.9 99 198 10.2 80 20 163 10 2.9 101 197 10.3 70 30 162 10 2.1 94 194 9.5 60 40 159 10 2.2 93 194 9.3 - 1001 159 10 2.0 102 183 10.6 100% PBT1 128 9 3.0 78 194 8.3 1 without 3% CaC03 and 30% glass fiber. Table 4: Impact modified grades of the PET-PTT-3% CaCO3-10% Lotader random copolymer/blend/alloy in comparison with PET, PTT and PBT polymer. Description , Izod impact J/m without Lotader Izod impact J/m with Lotader PET PTT 1001 - 42 71 88 12 56 97 85 15 67 114 80 20 65 111 70 30 52 109 60 40 51 90 - 1001 55 87 100% PBT1 48 80 1 without 3% CaC03. Results and discussion: Table 1: The Melting temperature, Tm of PET-PTT in 80:20 ratio with 3% CaC03 is 224.5 deg C which is similar to PBT with Tm of 223.5 deg C. Table 2: Tensile strength of PET-PTT in 85:15 and 80:20 ratios with 3% CaCQ3 respectively found to be higher than 100% PBT, PTT and PET. Tensile modulus and Impact strength of PET-PTT in all ratios with 3% CaC03 is found to be higher than 100% PBT and PET. Flexural strength and Flexural modulus of PET-PTT in 80:20 ratio with 3% CaC03 is found to have the highest value when compared to all other ratio of PET-PTT and 100% PBT, PTT and PET. Moreover all the ratios of PET-PTT are found to be better than 100% PBT. Mould shrinkage of PET-PTT in 60:40 ratio with 3% CaC03 is found to be comparable with 100% PBT. Table 3: Tensile strength and tensile modulus of PET-PTT in all ratios with 3% CaC03 and 30% glass fiber is found to be higher than 100% PBT with 30% glass fiber. Impact strength of PET-PTT in all ratios with 3% CaC03 and 30% glass fiber are found to be higher than 100% PBT and 100% PET with 30% glass fiber respectively. Flexural strength of PET-PTT in 88:12 ratio with 3% CaC03 and 30% glass fiber is found to have the highest value when compared to all other ratio of PET-PTT and 100% PBT, PTT and PET with 30% glass fiber. Moreover all the ratios of PET-PTT are found to be better than 100% PBT, 100% PTT and 100% PET with 30% glass fiber respectively. Flexural Modulus of PET-PTT in 88:12, 85:15, 80:20 ratios with 3% CaC03 and 30% glass fibre respectively are found to be higher than 100% PBT and PET. Table 4: Impact strength of PET-PTT in 85:15 ratio with 3% CaC03 and 10% Lotader is found to be higher when compared to all other ratio of PET-PTT and 100% PBT, 100% PTT and 100% PET with 10% Lotader respectively. Moreover all the ratios of PET-PTT are found to be better than 100% PBT, PTT and PET with 10% Lotader. Therefore the principal teachings of this invention are as follows: 1. PET: PTT in the ratio of 80:20 with 3% CaC03 has a Melting point of 224.5 °C which is similar to 223.5°C of PBT. Being similar, the processing conditions are same for both PBT and PET/PTT copolymer/blend/alloy. 2. PET: PTT in the ratio of 85:15 and 80:20 with 3 % CaC03 has better Tensile strength, Tensile Modulus, Flexural strength, Flexural modulus, Impact strength and Mold shrinkage than 100% PBT, PET and PTT indicating enhanced properties than individual polymers. 3. Similarly, PET:PTT in all ratios with 3 % CaC03 and 30 % Glass Fiber filled have better Tensile strength, Tensile Modulus, Flexural strength, Flexural modulus, Impact strength and Mold shrinkage than 100% PBT indicating enhanced properties than individual polymer. 4. With the incorporation of Impact Modifier, PET/PTT copolymer/blend/alloy can replace Polycarbonate with improved Impact strength. 5. Being a combination PET/PTT, the resultant copolymer/blend/alloy is more cost effective in comparison with PBT. 6. With the incorporation of hollow glass spheres, the specific gravity of PET/PTT copolymer/blend/alloy can be brought down the level of Nylon and replace Nylon with the improved properties. 7. Incorporation of PEN can improve U.V stability of the PET/PTT copolymer/blend/alloy to reduce the U.V degradation in molded products. While considering emphasis has been placed herein on the interrelationships between the component of the alloys disclosed in the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principals of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. Dated this 27th day of April 2006. Mohan Dewan of R. K. Dewan &Co Applicant's Patent Attorneys

Documents:

676-MUM-2006-ABSTRACT(26-4-2007).pdf

676-mum-2006-abstract(granted)-(13-3-2009).pdf

676-MUM-2006-CANCELLED PAGES(7-11-2008).pdf

676-MUM-2006-CLAIMS(26-4-2007).pdf

676-MUM-2006-CLAIMS(7-11-2008).pdf

676-mum-2006-claims(granted)-(13-3-2009).pdf

676-mum-2006-correspondance-po.pdf

676-mum-2006-correspondance-received.pdf

676-MUM-2006-CORRESPONDENCE(2-7-2007).pdf

676-MUM-2006-CORRESPONDENCE(7-11-2008).pdf

676-MUM-2006-CORRESPONDENCE(IPO)-(30-3-2009).pdf

676-mum-2006-description (provisional).pdf

676-MUM-2006-DESCRIPTION(COMPLETE)-(26-4-2007).pdf

676-mum-2006-description(granted)-(13-3-2009).pdf

676-MUM-2006-FORM 1(28-4-2006).pdf

676-MUM-2006-FORM 1(3-5-2006).pdf

676-MUM-2006-FORM 18(2-7-2007).pdf

676-mum-2006-form 2(26-4-2007).pdf

676-MUM-2006-FORM 2(COMPLETE)-(26-4-2007).pdf

676-mum-2006-form 2(granted)-(13-3-2009).pdf

676-MUM-2006-FORM 2(TITLE PAGE)-(26-4-2007).pdf

676-MUM-2006-FORM 2(TITLE PAGE)-(COMPLETE)-(26-4-2007).pdf

676-mum-2006-form 2(title page)-(granted)-(13-3-2009).pdf

676-MUM-2006-FORM 2(TITLE PAGE)-(PROVISIONAL)-(28-4-2006).pdf

676-MUM-2006-FORM 26(28-4-2006).pdf

676-MUM-2006-FORM 5(26-4-2007).pdf

676-mum-2006-form-1.pdf

676-mum-2006-form-2.doc

676-mum-2006-form-2.pdf

676-mum-2006-form-3.pdf