Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F255/00—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
  • C08F255/02—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00 on to polymers of olefins having two or three carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/14—Peroxides

Definitions

• thermoformable compositions More particularly, the present disclosure relates, to a thermoformable composition and processes for preparation thereof.
• the change in the melt strength or the deformation behavior under shear or tensile mode can be measured as the resistance of the material in terms of force or by using the indicators of polymer melt modification like elastic modulus (G'), material dampening (Tan ⁇ ), melt viscosity (Mv or ⁇ ) and the like.
• Elastic modulus is a measure of the elasticity and viscous modulus (G") is defined as the ability of a material to dissipate energy of a polymer melt as measured by dynamic rheological test.
• the ratio of G'VG' is the measure of material dampening (Tan ⁇ ), wherein higher the G' lower will be the Tan ⁇ .
• Enhancement of chain entanglement through incorporation of long chain branching and thus achieving high melt strength is possible through an increase in the molecular weight, the molecular weight distribution and the long chain branching. This can be monitored by determining the change in G' (increase), Tan ⁇ (drop in value) and ⁇ (increase). Dynamic rheological analyzer has been used to determine the change in G ⁇ Tan ⁇ and melt viscosity ( ⁇ ) at different frequencies (rad/sec).
• the resistance of a polymer melt to deformation is the melt strength under the given set of conditions.
• Melt flow index (MFI) or melt flow rate (MFR) is a measure of the resistance to flow of the polymer melt under a defined set of conditions (unit: dg/-min or g/10 min).
• MFI melt strength enhancement of polypropylene during the course of its modification. Change in the melt strength, as described in the embodiment is indicated through the changed MFI which drops with an increase in the molecular weight during incorporation of long chain branching.
• the measurement of the MFI was made as per ASTM D1238 using temperature as 230 °C and load as 2.16 Kgf.
• Die swell is the ratio of the extrudate diameter to the die orifice diameter of a rheometer. This is an indicator of melt elasticity (as indicated by elastic modulus- G'), higher the die swell, higher will be the melt elasticity.
• molecular weight averages are calculated as the number average molecular weight (Mn), the weight average molecular weight (Mw), the average molecular weight (Mz), the average molecular weight (Mz+1) in an increasing order of molecular weight.
• Mn number average molecular weight
• Mw weight average molecular weight
• Mz average molecular weight
• Mz+1 average molecular weight
• Flexural modulus is a measure of the ratio of the stress to the corresponding strain in a three point bending mode, within the elastic limit of polymer in solid state and is determined as per ASTM D 790.
• Izod impact is the Izod impact strength of a polymer in the solid state while clamping the notched test piece in cantilever position (vertical). The test is carried out as per ASTM D 256.
• PP with enhanced melt strength is prepared by various methods such as electron beam (EB) irradiation, reaction with low decomposition temperature peroxides and reactive extrusion with several peroxydicarbonates (PODIC).
• EB electron beam
• PODIC peroxydicarbonates
• US Patent No. 3970722 discloses a method for preparing a modified polypropylene by mixing crystalline propylene polymer, 0.1 to 5% organic peroxide and 0.1 to 7% modifying agent.
• the modifying agent may either be: (1) acrylic and methacrylic salts of Na, Ca, Mg, Zn, Al and Fe (III) or (2) compounds containing a phenol or benzyl group (e.g., 4-methacryloyl-oxymethylphenol).
• thermoformable composition with enhanced thermoformability.
• thermoformable propylene polymers It is another object of the present disclosure to provide thermoformable propylene polymers.
• thermoformable compositions It is yet another object of the present disclosure to provide a simple and cost-effective process for preparing thermoformable compositions.
• thermoformable composition prepared by melt kneading comprising a homogenous mixture of at least two polyfunctional aery late monomers in a polyolefin matrix having at least one organic peroxide in an amount less than 50 ppm, dispersed through said matrix.
• thermoformable composition is characterized by melt flow index (MFI) ranging between 0.10 g/ 10 min (g/min) and 10 g/10 min (g/min).
• MFI melt flow index
• thermoformable composition is characterized by elastic modulus (G') ranging between 500 and 4500 Pa, at a temperature ranging between 185 °C and 195 °C in melt state, with the frequency sweep mode ranging from 0.1 to 100 rad/s.
• G' elastic modulus
• thermoformable composition is characterized by material dampening (Tan ⁇ ) ranging between 0.5 and 1.5, at a temperature ranging between 185 °C and 195 °C in melt state, with the frequency sweep mode ranging from 0.1 to 100 rad/s.
• material dampening Tean ⁇
• thermoformable composition is characterized by melt viscosity ( ⁇ ) ranging between 2,000 and 50,000 Pa-s, at a temperature ranging between 185 °C and 195 °C in melt state, with the frequency sweep mode ranging from 0.1 to 100 rad/s.
• the thermoformable composition further comprises at least one additive selected from the group consisting of stabilizers, acid neutralizers, nucleators, antioxidants and lubricants, uniformly dispersed throughout the polyolefin matrix.
• said polyolefin matrix comprises at least one base propylene polymer selected from the group consisting of homopolypropylenes, copolymers of propylene with C 2 -C 2 o alpha-olefin, random propylene copolymers and polypropylene block polymers; said base propylene polymer having a melt flow index (MFI) ranging between 1.0 g/10 minutes and 12.0 g/10 minutes.
• MFI melt flow index
• said polyolefin matrix comprises a copolymer of propylene with at least one C 2 -C 20 alpha-olefin; said alpha olefin, in an amount ranging between 1% and 45% by weight of the copolymer, being selected from the group consisting of ethylene, 1- butene, 1-pentene, 1-hexene, methyl- 1-butene, methyl- 1-pentene, 1-octene and 1- decene.
• said polyfunctional acrylate monomer is selected from the group consisting of pentaerythritol triacrylate (PET A), trimethylolpropane triacrylate (TMPTA), hexadecylmethacrylate (HDMA), octadecylmethacrylate (ODA) and butylmethacrylate (BMA), in an amount ranging between 0.1% and 2% by weight of the thermoformable composition.
• PET A pentaerythritol triacrylate
• TMPTA trimethylolpropane triacrylate
• HDMA hexadecylmethacrylate
• ODA octadecylmethacrylate
• BMA butylmethacrylate
• said polyfunctional acrylate monomer comprises a combination of pentaerythritol triacrylate (PETA) and trimethylolpropane triacrylate (TMPTA).
• PETA pentaerythritol triacrylate
• TMPTA trimethylolpropane triacrylate
• said organic peroxide is at least one selected from the group consisting of diacyl peroxides, peroxyketals, peroxyesters, dialkyl peroxides and hydro peroxides.
• said organic peroxide is at least one selected from the group consisting of benzoyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, l,l-di-t-butylperoxy-2,4- di-t-butylcyclohexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (Luprox 101) and 3 ,6,9-triethyl-3 ,6,9-trimethyl- 1 ,4,7-triperoxonane.
• said stabilizer is at least one selected from the group consisting of Tetrakismethylene, (3,5-di-t-butyl-4-hydroxyhydroconnamate)methane (Irganox- 1010), Tris (2,4-di-t-butylphenol) phosphate (Irgafosl68) and Tetrakis(2,4-di-t- butylphenol-4,4'-biphenylenediphosphonite (PEPQ).
• said lubricant is calcium stearate.
• the present disclosure further provides an article prepared from the thermoformable composition; said article being selected from the group consisting of thermoformable sheets, spare wheel covers, dash boards, interior trims, door liners, noise suppressors, front covers, instrument panels, seats, engine covers, wheel covers, refrigerator liners, mixer bodies, television back covers, fan bodies, washing machine liners and air conditioner parts.
• thermoformable composition comprising the following steps:
• the step of mixing further comprises mixing at least one additive selected from the group consisting of stabilizers, acid neutralizers, nucleators, antioxidants and lubricants.
• said stabilizer is at least one selected from the group consisting of Tetrakismethylene, (3,5-di-t-butyl-4-hydroxyhydroconnamate)methane (Irganox- 1010), Tris (2,4-di-t-butylphenol) phosphate (Irgafosl68) and Tetrakis(2,4-di-t- butylphenol-4,4'-biphenylenediphosphonite (PEPQ).
• said lubricant is calcium stearate.
• said polyolefin matrix comprises at least one base propylene polymer selected from the group consisting of homopolypropylenes, copolymers of propylene with C 2 -C 20 alpha-olefin, random propylene copolymers and polypropylene block polymers; said base propylene polymer having a melt flow index (MFI) ranging between 1.0 g/10 minutes and 12.0 g/10 minutes.
• MFI melt flow index
• said polyolefin matrix comprises a copolymer of propylene with at least one C 2 -C 2 o alpha-olefin; said alpha olefin, in an amount ranging between 1% and 45% by weight of the copolymer, being selected from the group consisting of ethylene, 1- butene, 1-pentene, 1-hexene, methyl- 1-butene, methyl- 1-pentene, 1-octene and 1- decene.
• said polyfunctional acrylate monomer is selected from the group consisting of pentaerythritol triacrylate (PETA), trimethylolpropane triacrylate (TMPTA), hexadecylmethacrylate (HDMA), octadecylmethacrylate (ODA) and butylmethacrylate (BMA), in an amount ranging between 0.1% and 2% by weight of thermoformable composition.
• PETA pentaerythritol triacrylate
• TMPTA trimethylolpropane triacrylate
• HDMA hexadecylmethacrylate
• ODA octadecylmethacrylate
• BMA butylmethacrylate
• said polyfunctional acrylate monomer comprises a combination of pentaerythritol triacrylate (PETA) and trimethylolpropane triacrylate (TMPTA).
• said organic peroxide is at least one selected from the group consisting of diacyl peroxides, peroxyketals, peroxyesters, dialkyl peroxides and hydro peroxide.
• said organic peroxide is at least one selected from the group consisting of benzoyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, l,l-di-t-butylperoxy-2,4- di-t-butylcyclohexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (Luprox 101) and 3,6,9-triethyl-3,6,9-trimethyl- 1 ,4,7-triperoxonane.
• said homogenized admixture is fed into said kneader at a feed rate ranging between 8 and 15 kg/ hour.
• the melt pressure in the melt pump drops by a value ranging between 7 and 10%.
• the melt pressure of neat polymer has been found to be 140 bar.
• the drop in the melt pressure is an indicator of chain branching in the polymer, as branching is said to facilitate melt flowability at the set kneading conditions.
• the step of kneading is carried out at a temperature ranging between 170 and 260 °C.
• Fig. 1 (a) illustrates the reaction mechanism by which fragmentation of the polypropylene base polymer (PPBP) takes place in the absence of the polyfunctional acrylate monomers (PFAMs);
• Fig 1 (b) illustrates the reaction mechanism by which chain elongation of the PPBP results due to the addition of the PFAMs
• Fig. 2 illustrates the comparison between the deep draw ability of thermoformed polypropylene impact copolymer (PP-ICP) prepared by the commercial process (no modifier), Figure 2 (a) and that prepared by the process of the present disclosure (PET+TMPTA), Figure 2 (b).
• Fig. 3 illustrates a thermoformed part of an automotive interior made of the modified polypropylene impact copolymer (PP-ICP) of the present disclosure.
• HMS high melt strength polymers
• base propylene polymers with 0.1 to 1.0% of a polyfunctional acrylate monomer, in the presence of 10 to 50 ppm organic peroxide and 0.2 to 20% of at least one additive such as stabilizer, acid neutralizer, antioxidant and lubricant.
• the melt strength of the resultant HMS polymers is 30-60% greater than that of the base propylene polymers.
• melt flow index (MFI) of the polymers prepared by the process of 2860/MUM/2010 is found to range between 0.2 and 1.5 g/10 minutes.
• thermoformable composition comprising:
• the polyolefin matrix of the present disclosure in which the monomers and the peroxides(s) are dispersed typically comprises at least one base propylene polymer selected from the group that includes but is not limited to homopolypropylenes, copolymers of propylene with C 2 -C 2 o alpha-olefin, random propylene copolymers and polypropylene block polymers.
• the MFI of the base propylene polymer ranges between 1.0 g/10 minutes and 12.0 g/10 minutes.
• the C 2 -C 2 o alpha-olefin which forms a copolymer with propylene is selected from the group that includes but is not limited to ethylene, 1-butene, 1-pentene, 1-hexene, methyl- 1-butene, methyl- 1-pentene, 1- octene and 1-decene and is present in an amount ranging between 1% and 45% by weight of the copolymer.
• the organic peroxide of the present disclosure is present in an amount less than 50 ppm.
• the organic peroxide is at least one selected from the group that includes but is not limited to diacyl peroxides, peroxyketals, peroxyesters, dialkyl peroxides and hydro peroxides.
• the organic peroxide is at least one selected from the group that includes but is not limited to benzoyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, l,l-di-t-butylperoxy-2,4-di-t-butylcyclohexane, 2,5-dimethyl-2,5-di- (tert-butylperoxy)hexane (Luprox 101) and 3,6,9-triethyl-3,6,9-trimethyl-l,4,7- triperoxonane.
• Peroxide in the range of 10-50 ppm performs the job of modification showing enhancement in melt viscosity and crystallization temperature confirming thermformable-PP formation.
• the propylene polymer of the present disclosure has reduced yellowness due to the low content of the peroxide.
• the propylene polymer of the present disclosure is siibstantially free of peroxide, there is no need of controlling the content of peroxide which is otherwise required in order to keep the degradation of the polypropylene resin to a minimum.
• the peroxide free radical (R ) causes fragmentation of the polypropylene base polymer chain and thus, mars the objective of preparing thermoformable polypropylene polymers.
• This phenomenon of fragmentation has been demonstrated in Figure 1(a) where the polypropylene base polymer is represented by (PPBP) and the resultant unstable polypropylene macro free radical is represented by PPMFR.
• the PPMFR subsequently undergoes beta scission to yield fragments.
• the polyfunctional acrylate monomers are included in the composition of the present disclosure, the monomers stabilize the unstable PPMFR and make available multiple reactive sites; thereby facilitating chain elongation.
• the polyfunctional acrylate monomer of the present disclosure is selected from the group that includes but is not limited to pentaerythritol triacrylate (PETA), trimethylolpropane triacrylate (TMPTA), hexadecylmethacrylate (HDMA), octadecylmethacrylate (ODA) and butylmethacrylate (BMA).
• the monomer is present in an amount ranging between 0.1% and 2% by weight of the thermoformable composition.
• the thermoformable composition comprises a combination of pentaerythritol triacrylate (PETA) and trimethylolpropane triacrylate (TMPTA) as the polyfunctional acrylate monomer. It has been found that inclusion of two polyfunctional acrylate monomers in place of one polyfunctional acrylate monomer, reduces the MFI of the polymer effectively; thereby increasing its thermoformability.
• the thermoformable composition of the present disclosure further comprises at least one additive that is uniformly dispersed throughout the polyolefin matrix.
• the additive is selected from the group that includes but is not limited to stabilizers, acid neutralizers, nucleators, antioxidants and lubricants. These additives may be included in amounts effective to impart the desired properties. Stabilizers or stabilization agents may be employed to help protect the polymer resin from degradation due to the exposure to excessive temperatures and/or ultraviolet light.
• the stabilizer of the present disclosure is at least one selected from the group that includes but is not limited to Tetrakismethylene, (3,5-di-t-butyl-4-hydroxyhydroconnamate)methane (Irganox-1010), Tris (2,4-di-t-butylphenol) phosphate (Irgafosl68) and Tetrakis(2,4- di-t-butylphenol-4,4'-biphenylenediphosphonite (PEPQ).
• the lubricant is calcium stearate.
• thermoformable composition of the present disclosure has an MFI ranging between 0.10 g/10 min and 10.0 g/10 min. It is a known fact that that the melt flow index and thermoformability of a polymer are inversely proportional. Thus, the lower MFI values of the polymer of the present disclosure demonstrate high thermoformability. Further, other parameters of the thermoformable composition have been quantified such as the elastic modulus (G'), the material dampening (Tan ⁇ ) and the melt viscosity (r)). The elastic modulus (G') and the melt viscosity are directly proportional to the thermoformability whereas the material dampening (Tan 6) is inversely proportional to the thermoformability.
• the elastic modulus (G') of the thermoformable composition ranges between 500 and 4500 Pa
• the material dampening (Tan ⁇ ) ranges between 0.5 and 1.5
• the melt viscosity ( ⁇ ) ranges between 2,000 and 50,000 Pa-s.
• the afore-stated parameters have been quantified under a temperature ranging between 185 °C and 195 °C in melt state, with the frequency sweep mode ranging from 0.1 to 100 rad/s. In one embodiment, the temperature at which quantification is carried out is 190 °C. The characterization data, therefore, buttresses the proposition that the polymer of the present disclosure has high thermoformability.
• an article prepared from the afore-stated thermoformable composition is provided.
• the article is selected from the group that includes but is not limited to thermoformable sheets, spare wheel covers, dash boards, interior trims, door liners, noise suppressors, front covers, instrument panels, seats, engine covers, wheel covers, refrigerator liners, mixer bodies, television back covers, fan bodies, washing machine liners and air conditioner parts.
• thermoformable composition in accordance with yet another aspect of the present disclosure, there is provided a process for the preparation of the thermoformable composition.
• the process initially includes mixing at least two polyfunctional acrylate monomers and at least one organic peroxide in a polyolefin matrix to obtain an admixture.
• the polyolefm matrix of the present disclosure typically comprises at least one base propylene polymer selected from the group that includes but is not limited to homopolypropylenes, copolymers of propylene with C 2 -C 2 o alpha-olefin, random propylene copolymers and polypropylene block polymers.
• the MFI of the base propylene polymer ranges between 1.0 g/10 minutes and 12.0 g/10 minutes.
• the C 2 -C 2 o alpha-olefin which forms a copolymer with propylene is selected from the group that includes but is not limited to ethylene, 1-butene, 1-pentene, 1-hexene, methyl- 1-butene, methyl- 1-pentene, 1- octene and 1-decene and is present in an amount ranging between 1% and 45% by weight of the copolymer.
• the polyfunctional acrylate monomer of the present disclosure is selected from the group that includes but is not limited to pentaerythritol triacrylate (PETA), trimethylolpropane triacrylate (TMPTA), hexadecylmethacrylate (HDMA), octadecylmethacrylate (ODA) and butylmethacrylate (BMA).
• PETA pentaerythritol triacrylate
• TMPTA trimethylolpropane triacrylate
• HDMA hexadecylmethacrylate
• ODA octadecylmethacrylate
• BMA butylmethacrylate
• the monomer is present in an amount ranging between 0.1% and 2% by weight of the thermoformable composition.
• the thermoformable composition comprises a combination of pentaerythritol triacrylate (PETA) and trimethylolpropane triacrylate (TMPTA) as the polyfunctional acrylate mono
• the organic peroxide of the present disclosure is present in an amount less than 50 ppm.
• the organic peroxide is at least one selected from the group that includes but is not limited to diacyl peroxides, peroxyketals, peroxyesters, dialkyl peroxides and hydro peroxides.
• the organic peroxide is at least one selected from the group that includes but is not limited to benzoyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, l,l-di-t-butylperoxy-2,4-di-t-butylcyclohexane, 2,5-dimethyl-2,5-di- (tert-butylperoxy)hexane (Luprox 101) and 3,6,9-triethyl-3,6,9-trimethyl-l,4,7- triperoxonane.
• thermoformable composition of the present disclosure further comprises at least one additive that is uniformly dispersed throughout the polyolefin matrix.
• the additive is selected from the group that includes but is not limited to stabilizers, acid neutralizers, nucleators, antioxidants and lubricants.
• the stabilizer of the present disclosure is at least one selected from the group that includes but is not limited to Tetrakismethylene, (3,5-di-t-butyl-4-hydroxyhydroconnamate)methane (Irganox-1010), Tris (2,4-di-t-butylphenol) phosphate (Irgafosl68) and Tetrakis(2,4- di-t-butylphenol-4,4'-biphenylenediphosphonite (PEPQ).
• the lubricant is calcium stearate.
• the resultant admixture is further homogenized at a temperature ranging between 23 °C and 30 °C, in a high speed mixer.
• the speed of the step of homogenization ranges between 90 rpm and 300 rpm.
• the step of homogenization causes mere physical homogenization of the contents of the admixture.
• the resultant homogenized admixture is fed into said kneader at a feed rate ranging between 8 and 15 kg/ hour.
• the step of kneading causes a chemical reaction in the admixture, grafting of polyfunctional acrylate monomer onto the polymer chain which follows branching of the polymer chains that reduces the MFI and consequently increases the thermoformability of the resultant polymer composition.
• the melt pressure in the melt pump drops by a value ranging between 7 and 10%. In one embodiment, at a feed rate of 8 kg/hour, the melt pressure of neat polymer has been found to be 140 bar.
• the drop in the melt pressure is an indicator of chain branching in the polymer, as branching is said to facilitate melt flowability at the set kneading conditions.
• the step of kneading is carried out at a temperature ranging between 170 and 260 °C.
• Example 1 Preparation of thermoformable propylene polymer as per the process of the co-pending patent application number 2860/MUM/2010
• PETA pentaerythritol triacrylate
• PP-ICP 50% of the PP-ICP was blended with a concentrate of trifunctional monomer (co- agent/ modifier) containing peroxide with thorough mixing. In the subsequent step the remaining part of polymer was added and mixed perfectly to form a uniform dispersion of the modifier. Irganox-1010 (0.05% w/w based on total matrix used for modification) and Irgafos-168 (0.1% w/w based on total matrix) were added as the primary and secondary antioxidants respectively, followed by 0.06% calcium stearate these were added to the whole mass and blended. The hand mixing operation was repeated several times to ensure proper mixing. The extrusion of PP-ICP containing reactants was carried out on a lab model Buss-co-kneader.
• Zone-l 170 °C
• Zone-2 230 °C
• Zone-3 250 °C
• Zone-4 die zone
• the extruded material was quenched and pelletized.
• the modified samples were characterized for MFI, MW, MWD and melt rheological characteristics.
• Example 2 Preparation of thermoformable polypropylene polymer using TMPTA as a modifier
• Example 2 The process of Example 1 was repeated, except that TMPTA was used as the modifier in place of PETA.
• the modified samples were characterized for MFI, MW, MWD and melt rheological characteristics.
• thermoformable propylene polymer As per the process of the present disclosure, using a combination of PETA + TMPTA as a modifier.
• 500 g batch plain PP-ICP (MFI: 1.5 g/10 min) was used as base matrix for making the formulation as described in Example- 1, comprising 500 ppm of IrgaoxlOlO, 1000 ppm of Irgafosl68, 600 ppm of Cast, 0.25 % PETA, 0.25 % TMPTA and 15 ppm of LuperoxlOl .
• the prepared batch was extruded on a Buss-co-kneader with a temperature profile: Zone-1 : 170 °C; Zone-2: 230 °C; Zone-3: 250 °C; and Zone-4 (die zone): 260 °C at 90 rpm.
• Zone-1 170 °C
• Zone-2 230 °C
• Zone-3 250 °C
• Zone-4 die zone
• Table 1 Melt properties of PP-ICP before and after modification with single as well as mixed modifier
• Example 4 Thermoformability of the PP obtained by the process of the present disclosure
• the thermoformability of the PETA+TMPTA modified PP-IGP (invention of the present disclosure) and a known thermoformable PP-ICP sheet (prepared under identical processing conditions and having 2.5 mm thickness) was compared on a lab model machine for depth of draw. The details of the wooden mould used for the study are given below.
• PETA+TMPTA modified PP-ICP sheet developed by the process of the present disclosure could be drawn successfully up to a depth of 300 mm as demonstrated in Figure 2 (b) whereas the commercial thermoformable PP-ICP sheet failed to show this level of deep drawability as shown in Fig 2 (a).
• the PETA+TMPTA modified sheet was successfully thermoformed and showed a good mold conformation w.r.t. the thickness uniformity.
• Example 5 Applicability to homopolymer as well as copolymer.
• Polypropylene impact copolymer (PP-ICP with MI: 1.50) and Homo-PP (5MI) were initially modified using PETA as the only modifier under optimum extrusion conditions as described in Example 1.
• the result was a 1 kg batch of propylene polymer comprising optimum levels of peroxide, 500 ppm of IrgaoxlOlO, 1000 ppm _ of Irgafosl68, 600 ppm Cast, 0.4 and 1.0 wt % modifier (PETA), prepared at a temperature profile of 170-230-250-260 °C under 90 rpm.
• a control batch of propylene polymer was prepared that did not contain either the modifier or the peroxide.
• the MFI, Mv (using MFI data) and Tc of the batch were noted.
• a 1 kg batch of propylene polymer was prepared where the temperature profile was maintained as 170-230-250-260 0 at 90 rpm.
• the batch comprised 500 ppm of Irgaox- 1010, 1000 ppm of Irgafos 168 and 600 ppm of Cast.
• Table-3 Melt rheological and thermal characteristic before and after modification of Homo-PP (5MI) Sample PETA wt% w/w Luperox MFI g / 10 Mv, Pa-s Tc, °C
• the modified PP-ICP (PETA+TMPTA) as prepared under optimum reactive processing conditions as given in Example 2 was extruded in the form of a sheet of 2.5 mm thickness and 1220 mm width.
• the square pieces of sheet of area 1200 mm x 1220 mm were clamped on a commercial machine.
• a wooden family mold was used for thermoforming an automotive part.
• the sheet temperature was brought close to 200 °C (as measured by an infra-red gun) and pre-blown before thermoforming. A depth of draw of 300 mm retaining the required texture was obtained.
• a thermoformed article made up of modified PP-ICP (PETA+TMPTA) for automotive interior is shown in Fig. 3.
• the present disclosure provides a process for preventing homo-polymerization of the polyfunctional acrylate monomers during the extrusion process and consequently improving the grafting and branching efficiency along with having an overall impact on the process economy.
• the process of the present disclosure provides broad processing parameters whilst trying to maintain satisfactory Optical and mechanical properties required for target end-product applications.
• thermoformable polymers with optimum melt rheological characteristics and relatively broad molecular weight distribution to make the product compatible for thermoformability/ deep drawing.
• thermoformable propylene polymers with reduced yellowness.
• the present disclosure provides long chain branched polypropylenes in which the ⁇ integrity of the branch structure remains intact even after multiple thermal cycles.

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