Preform and method for the manufacture of a PEF container using said preform by injection stretch blow-molding

Abstract

A preform, which makes it possible to obtain PEF containers (bottles) having the awaited properties, notably mechanical, by an industrial injection stretch blow molding process, is of made of a thermoplastic PEF polymer of 2,5-FuranDiCarboxylic Acid (2,5-FDCA) monomer and monoethylene glycol (MEG) monomer and comprises a neck end 2, a neck support ring 3, and a closed tubular body portion 4. The preform is designed so as to produce, by injection stretch blow-molding, a container, the axial stretch ratio of which is greater than or equal to its hoop stretch ratio. Also provided is a plastic container 10, preferably a bottle, obtained by injection stretch blow-molding of PEF preform, the bottle 10 having an axial stretch ratio greater than or equal to the hoop stretch ratio. A method for manufacturing the bottle 10 is also provided.

Claims

1. A preform for the manufacture by stretch blow molding of a plastic container, preferably a bottle, said preform being of made by injection molding of at least one thermoplastic polymer of at least one FuranDiCarboxylic Acid (FDCA) monomer, preferably 2,5-FuranDiCarboxylic Acid (2,5-FDCA) monomer, and at least one diol monomer, preferably monoethylene glycol (MEG) monomer and said preform comprising: a neck end; a neck support ring; and a closed tubular body portion, the tubular body portion comprising a straight part having a length L and a bottom curved part having a radius R; said preform having a ratio /L, wherein is a specific outer diameter of the straight part of the closed tubular body portion and L is a generatrix length of the preform closed tubular body portion, L being such that L=L=2R/4, the ratio /L being such thatin an increasing order of preference: 0.10</L0.50, 0.15</L0.45, 0.20</L0.40, 0.25</L0.35.

2. A preform according to claim 1 wherein said preform is designed so as to produce, by injection stretch blow-molding a container, in a manner that the axial stretch ratio is greater than or equal to the hoop stretch ratio.

3. A preform according to claim 1, wherein a minimal thickness (t.sub.min) of a side wall of the closed tubular body portion isin mm and in an increasing order of preference: 1.0<t.sub.min3.5, 1.2<t.sub.min3.2, 1.5<t.sub.min3.0, 1.8<t.sub.min2.5.

4. A preform according to at least claim 1, the bottom curved part of which presents an extra-thickness on which a lower end of a blowpipe is intended to rest during a blowing of the injection stretch blow-molding.

5. A method of manufacturing a container, preferably a bottle, comprising the steps of: providing a preform, said preform being of made by injection molding of at least one thermoplastic polymer of at least one FuranDiCarboxylic Acid (FDCA) monomer, preferably 2,5-FuranDiCarboxylic Acid (2,5-FDCA) monomer, and at least one diol monomer, preferably monoethylene glycol (MEG) monomer, placing the preform in a mold having a cavity, blowing the preform in the mold with a blowing device including a blowpipe, adapted to supply the cavity with a fluid at a blowing pressure to form the container, so that an axial stretch ratio of the container with respect to the preform is greater than or equal to a hoop stretch ratio of the container with respect to the preform.

6. A method according to claim 5, wherein the blowing pressure is less than or equal to 35 bars, preferably 30 bars, more preferably 25 bars, more preferably 20 bars, more preferably 15 bars, more preferably 10 bars.

7. A method according to claim 5, wherein the end of the blowpipe is brought inside the preform against an extra-thickness of the bottom curved part of the preform so that said lower end presses on the preform and contributes to the stretching.

8. A method according to claim 5, further comprising a step of filling the bottle with a liquid, preferably a beverage.

9. A method according to claim 5, wherein a preform according to claim 1 is provided.

10. A method according to claim 5, wherein; the axial stretch ratio is greater than or equal toin an increasing order of preference: 3.5; 4.0; 4.15; 4.30; 4.5; 5.0; and the hoop stretch ratio is smaller than or equal toin an increasing order of preference: 4.0; 3.75; 3.60; 3.50; 3.40; 3.30; 3.20; 3.0; 2.5.

11. A method according to claim 5, wherein the container includes from the top to the base: a neck, a shoulder, a tubular body portion, and a bottom, and wherein the ratio defined as bottom mass BM/total mass TM]100, is such thatin % by weight and in an increasing order of preference: (BM/TM)10.5 1<(BM/TM)9 5<(BM/TM)8 6<(BM/TM)7.

12. A method according to claim 5, wherein the container comprises at least one imprint, which is preferably selected from the group consisting of splines, grooves, ribs, embossings, decorative patterns, gripping elements, trademark indications, production indications, Braille characters, and a combination thereof.

13. A method according to claim 11, wherein the bottom of the container includes: a terminal curved portion, an internal axially inwardly directed dome, a base joining the terminal curved portion to the dome, and reinforcements.

14. A method according to claim 13, wherein the reinforcements comprise radially extended grooves and/or ribs with respect to an axis on the bottom, said grooves and/or ribs being regularly arranged around the axis, preferably on the terminal curved portion and on the base, and possibly on the dome.

15. A method according to claim 13, wherein there is at least one imprint which is a bulge located close to the apex of the dome.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Further objects and advantages of the invention will emerge from the following disclosure of a particular embodiment of the invention given as a non limitative example, the disclosure being made in reference to the enclosed drawings in which:

(2) FIG. 1 is a longitudinal section through its axis A of the PEF preform according to a preferred embodiment of the invention.

(3) FIG. 1.sup.r a longitudinal section through its axis A.sup.r of a PET reference preform (10.sup.r) intended to be used in the manufacture by injection stretch blow-molding of a PET reference plastic container (1.sup.r), namely a bottle, identical to the PEF bottle of FIG. 3.

(4) FIG. 2 is an enlarged view of the detail referenced D on FIG. 1 representing the closed end of the PEF preform,

(5) FIG. 3 is a view of the PEF bottle obtained the PEF preform of FIG. 1, by an injection stretch blow molding process,

(6) FIG. 4 is a bottom view of the bottle of FIG. 3,

(7) FIGS. 5A; 5B; 5C are respectively/ a perspective bottom view of a part of the lower region of a bottle 10 which is a variant of the bottle 10 of FIG. 3; a side view of the bottom of the bottle of FIG. 5A; a bottom view of FIGS. 5A & 5B.

(8) On the Figures, the same reference numbers refer to the same or similar elements.

(9) FIG. 1 represents an injection moulded plastic preform 1 for the manufacture by blow molding of the thin-walled container, preferably a bottle 10, as represented on FIG. 3. Said preform 1 comprises from the top to the bottom: a neck end 2; a neck support ring 3; and a closed tubular body portion 4;

(10) According to a possibility, there can be a transition zone between the neck support ring 3 and the closed tubular portion 4.

(11) The neck end 2 and the neck support ring 3 form together the neck finish.

(12) The preform 1 is a hollow tube extending along an axis A and having a closed bottom end 5 and an opened top end 6.

(13) The top portion of the preform 1 close to the opened top end 6 and which is composed of the neck end 2 and of the neck support ring 3, does not undergo any transformation during the shaping of the bottle 10 by stretch blowing. So, the neck end 2 and of the neck support ring 3 correspond to the neck end 20 and to the neck support ring 30 of the bottle 10 as shown on FIG. 3.

(14) The remaining portion of the tube is the closed tubular body portion 4 which comprises a straight part 4.sub.1 (length L) starting just below the neck support ring to a bottom curved part 4.sub.2. Said straight part 4.sub.1 has a circular cross section, the external diameter of which can be steady, decreasing and/or increasing on at least one segment of the straight part 4.sub.1 of the closed tubular body 4. The thickness of the wall 5 of said straight part 4.sub.1 can vary but is at least partly steady.

(15) The preform 1 is also defined by the diameter and the length L, as shown on FIGS. 1&2. is the outer diameter of the straight part 4.sub.1 of the closed tubular body portion 4 measured at the middle of the longer segment of the straight part 4.sub.1, which has a steady thickness and L is the length of a generatrix of the closed tubular body 4 from the lower face of the neck support ring 3 to the lower end of the preform, i. e of the straight part 4.sub.1 and of the bottom curved part 4.sub.2. As the bottom curved part 4.sub.2 is circular and has a radius R, L=(2R)4+L.

(16) As a non-limitative example, the PEF preform 1 may have a of 25-28 mm, a L of 109-111 mm and so a /L of 0.225-0.256.

(17) As a comparison, the PET reference preform 10.sup.r shown on FIG. 1.sup.r (with the same reference numbers as in FIG. 1 with an exponent.sup.r) has a diameter .sup.r of 26 mm a length L.sup.r of 128 mm, and so a ratio .sup.r/L.sup.r of 0.203.

(18) The enlarged view of the region D of the preform 1 shown on FIG. 2, makes it appear that the bottom curved part 4.sub.2 presents an annular extra-thickness 6 on which the lower end of the blowpipe used in the manufacture process of a container (bottle 10) from the preform 1 by injection stretch blow molding, is intended to rest during the blowing. This feature improves the mechanical properties of the container (bottle 10) and leaves an imprint on the bottom of the container (bottle 10) as it will be presented hereafter.

(19) In the following of the description, the terms inside, inwards, inwardly and similar will refer to an element situated close to or directed towards the inner of the bottle 10 and the terms outside, outwards, outwardly and similar will refer to an element situated apart from or directed opposite to the housing or the axis.

(20) The bottle 10 obtained by stretch blow molding of the injection molded preform 1, is represented on FIGS. 3-5. Said bottle 10 is suitable for containing for example a liquid such as water. The bottle 10 of circular cross section, comprises a neck 20 a neck support ring 30 a neck extension 31 a shoulder 35 a tubular body portion 41, the wall of which is designated by the reference 50 and includes imprints 51. and a bottom 42

(21) Said bottom 42 includes: a terminal curved portion 421 an internal axially inwardly directed dome 423 a base 422 joining the terminal curved portion 421 to the dome 423 and reinforcements 424.

(22) The reinforcements 424 are radially extended grooves with respect to the axis (A) on the bottom 42. Said grooves 424 are regularly arranged around the axis (A.sup.r), on the terminal curve portion 421 and on the base 422. As shown on FIG. 4, some of the radial grooves 424, with the reference 424 are longer and extend further than the base 422, to the dome 423. These long grooves 424 are intercalated between the short grooves 424.

(23) In the variant of FIGS. 5A , 5B & 5C, the radial grooves 424 of the bottom 42 are also regularly arranged around the axis (A), on the terminal curve portion and on the base 422. They all start from the edge of the terminal curve portion 421 (FIG. 5B) and have substantially the same length.

(24) As a non-limitative example, the bottle 10 may have an axial stretch ratio of 4.19 and a hoop stretch ratio of 3.55.

(25) This bottle 10 according to this non limitative embodiment is also characterized by a [bottom mass BM/total mass TM].Math.100 ratio of [3/26]100=11.5%

(26) Although the invention has been disclosed with a cylindrical bottle comprising several grooves as imprints, the invention is not limited thereto. In particular, the bottle could be of any other suitable shape, such as cylindrical of elliptic, polygonal or other cross-section. Besides, the envelop could be provided with one or several imprints consisting in a local deformation in recess, as previously disclosed in relation with grooves, or in a local deformation in relief, i.e. protruding, with respect to the two adjacent portions. In the later case, the intermediate portion of such imprint presents an apex shifted outwardly, i.e. opposite to the axis A, with respect to the two edges. Thus, the imprint could be of any kind, especially selected from the group consisting of splines, grooves, ribs, embossings, decorative patterns, gripping elements, trademark indications, production indications, Braille characters and a combination thereof.

(27) The bottle 10 can be filled with a liquid, such as water or another beverage, before a cap is screwed and sealed to the neck 5.

(28) The bottle 10 described in this example is made of a thermoplastic polymer of at least one FuranDiCarboxylic Acid (FDCA) monomer and at least one diol monomer. In particular, the thermoplastic polymer is a PolyEthyleneFuranoate (PEF) based on biobased 2,5-FDCA and biobased MonoEthyleneGlycol (MEG). The preparation of the polymer and the manufacture of the bottle are detailed below.

(29) Materials 2,5-furandicarboxylic acid (2,5-FDCA) and dimethyl-2,5-furandicarboxylate (DMF) for example prepared according to WO2010/077133A1 or WO 2013/062408. MEG: biosourced MEG, as diol. PET (comparative): PET w170 supplied by Indorama, with the following features: glass transition temperature, Tg=75 C., melting temperature, Tf=235 C., density (amorphous), d=1.33.

(30) Preparation of the PEF Polymer

(31) PEF resin was provided by Avantium. Recipes and methods used to prepare the PEF resin were previously disclosed (in part) in WO2010077133, in WO2013062408, in Combinatorial Chemistry & High Throughput Screening, 2012, 15(2), p180-188 and in ACS Symposium Series 1105 (Biobased Monomers, Polymers, and Materials), 2012, p1-13.

(32) GPC measurements were performed on a Merck-Hitachi LaChrom HPLC system equipped with two PLgel 10 m MIXED-C (3007.5 mm) columns. Chloroform:2-chlorophenol 6:4 solvent mixture was used as eluent. Calculation of the molecular weight was based on polystyrene standards and carried out by CirrusTM PL DataStream software.

(33) Preparation of Sample 1b (PEF 1b)

(34) Melt polymerization with Ti-Sb catalyst system was carried out in a stirred batch reactor. Dimethyl-2,5-furandicarboxylate (30.0 kg), and bioethylene glycol (20.2 kg) were mixed under nitrogen in the pre-dried reactor, while increasing the product temperature to 190 C. At a product temperature of 110 C., a solution of 22.195 g Ti(IV) butoxide in 200 mL toluene was added, and the reaction mixture was heated further. At a product temperature of 165 C., methanol starts to distill off. After most of the MeOH had distilled off at a product temperature of 190 C., vacuum was applied slowly to 300 mbar and reaction was continued for ca 90 minutes, while the product temperature was slowly raised to 200 C. Then vacuum was released and a solution of 14.885 g of triethyl phosphonoacetate in 150 mL, ethylene glycol was added, followed after five minutes by the addition of Sb glycolate (9.50 g Sb2O3 dissolved in 685 mL ethylene glycol). Vacuum was applied slowly to 150 mbar at which pressure most of the excess ofethylene glycol was removed via distillation. Finally, the vacuum was reduced as much as possible, but definitely below 1 mbar. The product temperature was raised to 235 C. and the molecular weight increase was monitored by measuring the stirrer torque. The polymer that was obtained from the reactor was shown to have a Mn of 14500 g/mol and an Mw/Mn of 2.3. Solid state polymerization was then performed to increase the molecular weight of the polymer. First, crystallization of the polymer was performed at 110 C. in an oven. Subsequently, the polymer was charged into a tumble dryer, a vacuum of 6 mBar was applied, and the temperature was slowly raised to 190-200 C. Care was taken that polymer particles do not stick together. The molecular weight increase was monitored by solution viscometry on drawn samples. The final polymer, after solid state polymerisation, had a Mn of 30300 and Mw/Mn of 2.6.

(35) Preparation of Sample 3b1 (PEF 3b1)

(36) Melt polymerization with Zn-Sb catalyst system was carried out in a stirred batch reactor. Dimethyl-2,5-furandicarboxylate (20.0 kg), bioethylene glycol (15.5 kg), a solution of 7.65 anhydrous Zn(OAc)2 in 80 mL of bioethylene glycol, and Sb glycolate (4.10 g Sb2O3 dissolved in 230 mT, ethylene glycol) were mixed under nitrogen in the pre-dried reactor, while increasing the product temperature to 210 C. At a product temperature of 150 C., methanol starts to distill off. After most of the MeOH had distilled off, vacuum was applied slowly to 300 mbar and reaction was continued for ca 120 minutes, while the product temperature was kept at 200-210 C. Then vacuum was released and a solution of 12.65 g of triethyl phosphonoacetate in 60 mL ethylene glycol was added, followed after five minutes by the addition of Sb glycolate (4.10 g Sb2O3 dissolved in 230 mT, ethylene glycol). Vacuum was applied slowly to 150 mbar at which pressure most of the excess of ethylene glycol was removed via distillation. Finally, the vacuum was reduced as much as possible, but definitely below 1 mbar. The product temperature was raised to 240-245 oC and the molecular weight increase was monitored by measuring the stirrer torque. The polymer that was obtained from the reactor was shown to have a Mn of 15900 g/mol and an Mw/Mn of 2.3. Solid state polymerization was then performed to increase the molecular weight of the polymer. The polymer was charged into a tumble dryer, and dried under an nitrogen atmosphere at 110 C. Then a vacuum of 6 mBar was applied, and the temperature was slowly raised to 190-200 C. Care was taken that polymer particles do not stick together. The molecular weight increase was monitored by solution viscometry on drawn samples. The final polymer, after solid state polymerisation, had a Mn of 33000 and Mw/Mn of 2.6.

(37) Manufacture of the Preform

(38) The blow molding process implements a 25 g preform 1 made of the thermoplastic polymer PEF, the preparation of which has been hereinabove described.

(39) As a non-limitative example, the preform 1 may have a total height Hp measured along the axis A of 103 mm and an internal diameter varying from 24 mm close to the closed bottom end 4.sub.2 to 26 mm close to the neck support ring 3.

(40) To manufacture 25 g preforms 1 of the above disclosed type, a 20 kg sample of the above disclosed thermoplastic polymer PEF 3b1 is used in a Netstal Elion 800 injection molding machine. The material was heated to 255 C., with a cycle time of 17.63 s.

(41) Preforms 1.sup.r as shown on FIG. 1.sup.r were made with the thermoplastic polymer PET, the preparation of which has been hereinabove described from Indorama, at a 28 g weight for comparison with the thermoplastic polymer PEF. The matter was heated to 270 C., with a cycle time of 20.04 s.

(42) As a non-limitative example, the preform 1.sup.r may have a total height Hp measured along the axis A of 121 mm and an internal diameter varying from 20 mm close to the closed bottom end 4.sup.r.sub.2 to 24 mm close to the neck support ring 3.sup.r.

(43) Preforms 1.sup.o identical to those shown on FIG. 1.sup.r were made with the thermoplastic polymer PEF 1b, the preparation of which has been hereinabove described, for comparison with the PEF preform 1. The material was heated to 250 C., with a cycle time of 17.02 s.

(44) As a non-limitative example, the preforms 1.sup.r & 1.sup.o may have a total height Hp measured along the axis A of 121 mm and an internal diameter varying from 20 mm close to the closed bottom end 4.sup.r.sub.2, to 24 mm close to the neck support ring 3.sup.r.

(45) Manufacturing Method of the Bottle

(46) The bottle according to the invention is preferably manufactured by a blow molding process implementing a mold, such as a Sidel SBO 1 machine, having a cavity comprising one or several imprinting members, and a blowing device adapted to supply the cavity with a fluid at a blowing pressure.

(47) The PEF preforms 1 where heated to a surface temperature of 120 C. After the PEF preforms 1 have been placed in the mold at a cold temperature (10 C-13 C.), the preforms 1 can be blown through injection of the fluid at the blowing pressure within the preform through the opened top end, by means of a blowpipe which leans on the annular extra-thickness 5. In particular, the preforms 1 were blown to bottles 10 of the above disclosed type, namely a 1.5 L type with a design typical of still water, presenting grooves 51, 424, 424.

(48) Thanks to the use of the thermoplastic polymer PEF, the blowing pressure can be lowered to 35 bars or less, and especially, in an increasing order of preference, to 30 bars, 25 bars, 20 bars, 15 bars or 10 bars. In particular, the preforms 1 were blown with a blowing pressure of 34 bars to bottles 10.

(49) the PEF preforms 1.sup.o were transformed into bottles 10.sup.o by the same stretch blow molded process.

(50) The PET preforms 1.sup.r were heated to a surface temperature of 108 C-110 C., placed in the mold at cold temperature (10 C-13 C.) and blown, at a blowing pressure greater than 35 bars, to the same 1.5 L type bottles 10 with a design typical of still water, presenting grooves 51, 424, 424, hereafter referred to as reference PET bottles 10.sup.r. Good material distribution was achieved in all cases. The so produced PET bottles 10.sup.r are identical to the above described PEF bottles 10.

(51) Tests and Results

(52) In order to assess the good mechanical properties of the PEF bottles, a drop test is carried out.

(53) PEF bottles 10: 25 grams

(54) PEF bottles 10.sup.o: 28 grams

(55) Protocol BOTTLES DROP TEST

(56) The objective of this drop test is to measure the resistance of a bottle filled and capped at a cumulative and vertical drop. The bottle is dropped from different heights: distance between the bottom of the bottle and a metallic pad presenting a 10 angle from the vertical plan of the floor.

(57) For this purpose, the bottle is filled with water at 15 C. 2 C. and a level of water at 100 mm5 mm and is capped. The bottle is conditioning during 24 hours at room temperature. Then, the bottle is dropped. The fall of the bottle is free, but the body of the bottle is guided with a tube. The tube has a diameter bigger than the maximal diameter of the bottle.

(58) As it is a cumulative drop count, the drops on the same bottle are done until its breakage.

(59) Results:

(60) TABLE-US-00001 TABLE 1 Number of Number of Number of Number of Number of Number of drops drops drops drops drops Dropping drops passed passed passed passed passed passed height PEF bottles PEF bottles PEF bottles PEF bottles PEF bottles PEF bottles (m) 10 10 10 10 10 10 1 2 0 0 0 1 0 1.15 8 1.3 5 1.45 8 1.6 5 1.75 12 2 6 2 7

(61) For the bottle 10 according to the invention, for each of the 7 heights, a new bottle was dropped until it breaks. For instance at the height of 1.75 meter, the bottle passed 12 drops at this eight, and broke at the 13.sup.th drop. For the bottles 10.sup.o made of PEF out preform 1.sup.o, for, 5 bottles were dropped at 1.0 meter. Only one bottle passed once the impact test.

(62) TABLE-US-00002 TABLE 2 Number of drops Dropping passed PEF bottles height (m) 10 0.5 4/5 1 1/5 2 0/5

(63) In this table are reported the drop test for bottles 10.sup.o made of PEF out preform 1.sup.o. For each of the heights (50 cm, 1 m, 2 m), 5 bottles were dropped. At 50 cm, 4 passed the first drop, one broke at the first drop. At 1.0 meter, one passed the first drop, the four others broke. At 2.0 meters, all broke on the first drop.

(64) These results show the PEF bottle 10.sup.o obtained from a preform 1.sup.o have a much higher failure rate at the drop test when compared the PEF bottle 10 made from a preform 10 according to the invention.