Glycolic acid polymer

Abstract

The present invention provides (i) glycolic acid (GA); (ii) optionally, at least one hydroxy acid different from GA, having only one hydroxyl group and only one carboxylic acid group [hydroxy acid (A)], where the molar amount of hydroxy acid (A) is at most 5 mol % relative to the sum of the moles of GA and hydroxy acid (A); (iii) at least one polyol having at least three hydroxyl groups and no carboxylic acid group [polyol (H)]; (iv) at least one alcohol having one or two hydroxyl groups and no carboxylic acid group [alcohol (AO)]. )]; (v) optionally at least one carboxylic acid containing one carboxylic acid group and no hydroxyl groups [monoacid (C)]; and (vi) optionally at least one polyacid containing at least two carboxylic acid groups and no hydroxyl groups [polyacid (O)], wherein the amount of polyacid (O) is such that the number of its carboxylic acid groups is comprised between 0.025 and 0.900% relative to the total number of hydroxyl groups of glycolic acid and, if present, hydroxy acid (A).

Description

Technical Field

[0001] This application claims priority to European Patent Application No. 19315162.8, filed on December 18, 2019, US Patent Application No. 62 / 950275, filed on December 19, 2019, and US Patent Application No. 63 / 088067, filed on October 6, 2020, the entire contents of each of these applications are hereby incorporated by reference herein for all purposes.

[0002] The present invention relates to novel glycolic acid polymers, methods for producing the polymers, compositions containing the polymers, methods for producing multilayer products containing the polymers or the compositions, and articles produced therefrom.

[0003] Due to its excellent mechanical and barrier properties combined with biodegradability, glycolic acid polymer (PGA) is a polymer of great interest for numerous applications in consumer, oil and gas, and biomedical uses.

[0004] In small-sized (less than 500 ml) multilayer bottles widely used for beverages such as tea, fruit juice, carbonated beverages, soft drinks, etc., which require a long shelf life, an excellent gas barrier combined with compatibility with the mechanical recycling of polyethylene terephthalate (PET) makes it a preferred material.

[0005] In oil and gas applications, PGA is a preferred material for use as a downhole tool or downhole tool member during drilling and fracturing operations. High strength and degradability allow the material to play a temporary role in the process and decompose and disappear without the need for drill-out.

[0006] The technique provides a chain-like PGA that is essentially composed of repeating units -[CH2-C(O)-O]- by polycondensation of cyclic glycolide. On the other hand, the production of PGA polymers from the direct polycondensation of glycolic acid in the presence of additional modifying / branching monomers has been proposed as an economical and efficient alternative that provides high molecular weight PGA with advantageous rheological behavior.

[0007] In this field, U.S. Patent No. 7,153,587 (Mitsui Chemicals, Inc.) on December 26, 2006 provides a polyester resin containing (a-1) 45 to 99 mol% of oxycarboxylic acid units having 5 or fewer carbon atoms, (a-2) 0.5 to 27.5 mol% of aromatic dicarboxylic acid units, and (a-3) 0.5 to 27.5 mol% of short-chain aliphatic diol units having 4 or fewer carbon atoms, and containing (a-1) to (a-3) in a total amount of 95 mol% or more, where the oxycarboxylic acid is preferably glycolic acid; the aromatic carboxylic acid can be isophthalic acid, phthalic acid, or 2,6-naphthalenedicarboxylic acid; the short-chain aliphatic diol can be any of ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and where the polyester can additionally contain units derived from aliphatic dicarboxylic acids and / or monomers having three or more functional groups, such as polyfunctional acids having three or more carboxyl groups, polyfunctional alcohols having three or more hydroxyl groups, and units derived from hydroxyacids where the total of hydroxyl groups and carboxyl groups exceeds 3. Nevertheless, the PGA provided in this document tends to lack barrier properties compared to PGA that is essentially composed of glycolic acid units.

[0008] Therefore, a technique for producing PGA by direct polycondensation of glycolic acid using a triol (trimethylolpropane) and a diacid (isophthalic acid) as branching agents has been developed, leading to an increase in the melt strength for processing of PGA.

[0009] In this field, International Publication No. WO 2018 / 115008 pamphlet (SOLVAY SA), June 28, 2018, discloses a branched glycolic acid polymer obtained from a polycondensation reaction of a monomer mixture consisting of: (i) glycolic acid (GA); (ii) optionally, at least one hydroxy acid [hydroxy acid (A)] having only one hydroxyl group and only one carboxylic acid group different from GA (where the molar amount of hydroxy acid (A) is at most 5 mol% based on the total moles of GA and hydroxy acid (A)); (iii) at least one polyol [polyol (H)] containing at least three hydroxyl groups and no carboxylic acid group; (iv) at least one aromatic diacid [diacid (AR)] containing two aromatic carboxylic acid groups and no hydroxyl group; and (iv) optionally, at least one carboxylic acid [monoacid (C)] having one carboxylic acid group and no hydroxyl group, wherein the amount of polyol (H) is such that the number of its hydroxyl groups is included in the range of 0.050 to 0.750% relative to the total number of carboxyl groups of glycolic acid and, if present, hydroxy acid (A); the amount of diacid (AR) is such that the number of its carboxylic acid groups is included in the range of 0.050 to 0.750% relative to the total number of hydroxyl groups of glycolic acid and, if present, hydroxy acid (A); and, if present, the amount of the monoacid (C) is such that the number of its carboxylic acid groups is included in the range of 0.0001 to 0.010% relative to the total number of hydroxyl groups of glycolic acid and, if present, hydroxy acid (A).

[0010] However, it has been observed that the polymers obtained thanks to this technology exhibit a significant decrease in melt viscosity, i.e., less satisfactory melt stability, during exposure to temperature and shear in typical melt processing applications. This leads to difficult processing conditions and unpredictable melt performance in the materials.

[0011] Accordingly, in order to obtain the benefits of a larger polymer processing window for typical melt processing techniques, and to have a more stable polymer that is easier to handle and has more predictable rheological behavior during pelletization, compounding, injection molding, blow molding, compression molding, and film extrusion, there is still a need for improved branched glycolic acid polymers with higher melt stability.

[0012] The present invention relates herein to a glycolic acid polymer [polymer (PGA)], wherein the polymer PGA comprises (i) glycolic acid (GA); (ii) optionally, at least one hydroxy acid [hydroxy acid (A)] having only one hydroxyl group and only one carboxylic acid group different from GA, wherein the molar amount of hydroxy acid (A) is at most 5 mol% based on the total moles of GA and hydroxy acid (A); (iii) at least one polyol [polyol (H)] containing at least three hydroxyl groups and no carboxylic acid group; (iv) at least one alcohol [alcohol (AO)] containing one or two hydroxyl groups and no carboxylic acid group; (v) optionally, at least one carboxylic acid [monoacid (C)] containing one carboxylic acid group and no hydroxyl group; (vi) optionally, at least one polyacid [polyacid (O)] containing at least two carboxylic acid groups and no hydroxyl group, wherein the amount of polyacid (O) is such that the number of its carboxylic acid groups is included in the range of 0.025 to 0.900% relative to the total number of hydroxyl groups of glycolic acid and, if present, hydroxy acid (A) and relates to a polymer PGA obtained from a polycondensation reaction of a monomer mixture containing the same.

[0013] The polymer (PGA) of the present invention is obtained from the polycondensation reaction of a monomer mixture containing: (i) glycolic acid; (ii) optionally at least one hydroxy acid (A), where the molar amount of the hydroxy acid (A) is at most 5 mol% based on the total moles of GA and the hydroxy acid (A); (iii) at least one polyol (H); (iv) at least one alcohol (AO); (v) optionally at least one monocarboxylic acid (C); and (vi) optionally at least one polyacid (O), where the amount of the polyacid (O) is such that the number of its carboxylic acid groups is included in the range of 0.025 to 0.900% relative to the total number of hydroxyl groups of glycolic acid and, if present, the hydroxy acid (a).

[0014] Preferably, the present invention is a glycolic acid polymer [polymer (PGA)], wherein the polymer PGA is (i) glycolic acid (GA); (ii) optionally at least one hydroxy acid [hydroxy acid (A)] having only one hydroxyl group and only one carboxylic acid group different from GA, where the molar amount of the hydroxy acid (A) is at most 5 mol% based on the total moles of GA and the hydroxy acid (A); (iii) at least one polyol [polyol (H)] containing at least three hydroxyl groups and no carboxylic acid group; (iv) at least one alcohol [alcohol (AO)] containing one or two hydroxyl groups and no carboxylic acid group, preferably at least one diol [diol (D)] containing two hydroxyl groups and no carboxylic acid group; (v) optionally at least one monocarboxylic acid [monocarboxylic acid (C)] containing one carboxylic acid group and no hydroxyl group and relates to a polymer PGA obtained from the polycondensation reaction of a monomer mixture consisting of these components.

[0015] In such preferred embodiments, impurities, defects and chain ends may be present in limited amounts without significantly affecting the performance of the polymer (PGA), but the polymer (PGA) does not substantially contain any other units derived from monomers different from the above-mentioned monomers. In such a case, the polymer (PGA) preferably does not contain any units derived from monoacid (C) and polyacid (O) (in particular, does not contain any units derived from diacid and triacid).

[0016] More preferably, the present invention is a glycolic acid polymer [polymer (PGA)], wherein the polymer PGA is (i) glycolic acid (GA); (ii) optionally, at least one hydroxy acid [hydroxy acid (A)] having only one hydroxyl group and only one carboxylic acid group different from GA (wherein the molar amount of hydroxy acid (A) is at most 5 mol% based on the total moles of GA and hydroxy acid (A)); (iii) at least one polyol [polyol (H)] containing at least three hydroxyl groups and no carboxylic acid group; (iv) at least one alcohol [alcohol (AO)] containing one or two hydroxyl groups and no carboxylic acid group, preferably at least one diol [diol (D)] containing two hydroxyl groups and no carboxylic acid group and relates to a polymer PGA obtained from a polycondensation reaction of a monomer mixture consisting of

[0017] In such more preferred embodiments, impurities, defects and chain ends may be present in limited amounts without these significant effects on the performance of the polymer (PGA), but the polymer (PGA) therefore does not substantially contain any other units derived from monomers different from the above-mentioned monomers. In such a case, the polymer (PGA) more preferably does not contain any units derived from monoacid (C) and polyacid (O) (in particular, does not contain any units derived from diacid and triacid).

[0018] Most preferably, the present invention is a glycolic acid polymer [polymer (PGA)], wherein the polymer PGA is (i) glycolic acid (GA) and; (ii) optionally, at least one hydroxy acid [hydroxy acid (A)] having only one hydroxyl group and only one carboxylic acid group different from GA (wherein the molar amount of hydroxy acid (A) is at most 5 mol% with respect to the total moles of GA and hydroxy acid (A)) and; (iii) at least one polyol [polyol (H)] containing at least three hydroxyl groups and no carboxylic acid group; (iv) at least one diol [diol (D)] containing two hydroxyl groups and no carboxylic acid group and relates to a polymer PGA obtained from a polycondensation reaction of a monomer mixture consisting of.

[0019] In such a more preferred embodiment, impurities, defects and chain ends may be present in limited amounts without significantly affecting the performance of the polymer (PGA), but the polymer (PGA) does not substantially contain any other units derived from monomers different from the above-mentioned monomers. In such a case, the polymer (PGA) more preferably does not contain any units derived from monoalcohol (MO), monoacid (C) and polyacid (O) (in particular, does not contain any units derived from diacid and triacid).

[0020] The polymer (PGA) contains units derived from the polycondensation of, inter alia, GA and optionally hydroxy acid (A) as defined above. The choice of said hydroxy acid (A) is not limited and any hydroxyl acid capable of polycondensing, i.e., forming macromolecules by condensation (chain addition of monomers by elimination of water), can be used.

[0021] The hydroxy acid (A) is preferably selected from the group consisting of lactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxypentanoic acid, 5-hydroxypentanoic acid, and 6-hydroxycaproic acid. Generally, a hydroxy acid (A) having a primary alcohol is preferred because it is more reactive. In this regard, good results can be obtained especially when the hydroxy acid (A) is lactic acid (LA) (either in the racemic mixture or as a single isomer, the L-isomer or the D-isomer).

[0022] In one variant of the invention, both GA and, if present, the hydroxy acid (A) are of bio-origin, i.e., derived from natural and renewable raw materials, as opposed to fossil raw materials. The use of bio-origin PGA and, if applicable, the hydroxy acid (A) enables the synthesis of "environmentally friendly" polymers, i.e., polymers synthesized from renewable raw materials.

[0023] If present, the amount of the hydroxy acid (A) is at most 5 mol%, preferably at most 4 mol%, more preferably at most 3 mol% based on the total number of moles of GA and the hydroxy acid (A); and / or the amount can advantageously be as low as about 0.1 mol% based on the total moles of GA and the hydroxy acid (A). It is generally understood that the amount of the hydroxy acid (A) will be adjusted to possibly provide certain advantages without having a very serious adverse effect on the barrier performance appropriate for the PGA polymer structure.

[0024] The polymer (PGA) according to the present invention is characterized in that, in particular, the hydroxy acid (A) is selected from the group consisting of lactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxypentanoic acid, 5-hydroxypentanoic acid and 6-hydroxycaproic acid, preferably the hydroxy acid (A) is lactic acid (LA) (either in the racemic mixture or as a single isomer, the L-isomer or the D-isomer), and / or the hydroxy acid (A) is present in an amount of at most 4 mol%, more preferably at most 3 mol%, based on the total moles of GA and the hydroxy acid (A).

[0025] Embodiments in which no additional hydroxy acid (A) is used in combination with GA are within the scope of the present invention and may be preferred from the viewpoint of maximizing barrier performance.

[0026] The polyol (H) contains at least three hydroxyl groups, i.e., three hydroxyl groups covalently bonded to the carbon atoms of the polyol (H).

[0027] The selection of the polyol (H) is not particularly limited. The polyol (H) is - Triols selected particularly from the group consisting of glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, 2,3-di(2'-hydroxyethyl)-cyclohexan-1-ol, hexane-1,2,6-triol, 1,1,1-tris(hydroxymethyl)ethane, 3-(2'-hydroxyethoxy)propane-1,2-diol, 3-(2'-hydroxypropoxy)-propane-1,2-diol, 2-(2'-hydroxyethoxy)-hexane-1,2-diol, 6-(2' hydroxypropoxy)-hexane-1,2-diol, 1,1,1-tris-[(2'-hydroxyethoxy)-methylethane, 1,1,1-tris-[(2'-hydroxypropoxy)-methyl-propane, 1,1,1-tris-(4'-hydroxyphenyl)ethane, 1,1,1-tris-(hydroxyphenyl)-propane, 1,1,5-tris-(hydroxyphenyl)-3-methylpentane, trimethylolpropane ethoxylate, trimethylolpropane propoxylate, tris(hydroxymethyl)aminomethane; - Tetrols selected particularly from the group consisting of diglycerol, di(trimethylolpropane), pentaerythritol, 1,1,4-tris-(dihydroxyphenyl)-butane; - Polyols containing five hydroxyl groups, particularly triglycerol; - Polyols containing six hydroxyl groups, particularly dipentaerythritol, mannitol, sorbitol; and - Polyols containing eight hydroxyl groups, particularly tripentaerythritol can be selected from the group consisting of.

[0028] Preferred polyols (H) are triols (particularly triols selected from the group consisting of glycerol, trimethylolpropane and trimethylolbutane) and tetrols (particularly pentaerythritol) as detailed above.

[0029] A polyol (H) which has been found to provide particularly good results within the framework of the present invention is trimethylolpropane.

[0030] The polyol (H) is used in an amount such that the number of its hydroxyl groups is preferably included in the range of 0.050 to 1.200% relative to the total number of carboxyl groups of glycolic acid and, if present, the hydroxy acid (A).

[0031] The polyol (H) is used in an amount such that the number of its hydroxyl groups is preferably at least 0.050%, more preferably at least 0.075%, still more preferably at least 0.100%, most preferably at least 0.120% and / or preferably at most 1.200%, more preferably at most 1.000%, still more preferably at most 0.750%, particularly more preferably at most 0.650%, most preferably at most 0.600% relative to the total number of carboxyl groups of glycolic acid and, if present, the hydroxy acid (A).

[0032] The amount of the polyol (H) such that the number of its hydroxyl groups is 0.120 to 0.600% relative to the total number of carboxyl groups of glycolic acid and, if present, the hydroxy acid (A) has been found to be particularly useful according to a preferred embodiment of the present invention.

[0033] The polymer (PGA) according to the present invention is characterized in that, in particular, the polyol (H) is selected from the group consisting of triols; tetraols; polyols containing five hydroxyl groups; polyols containing six hydroxyl groups; and polyols containing eight hydroxyl groups, all as defined above, and / or here, the polyol (H) is used in an amount such that the number of its hydroxyl groups is as defined above.

[0034] The alcohol (AO) contains one or two hydroxyl groups, i.e., one or two hydroxyl groups covalently bonded to the carbon atoms of the alcohol (AO).

[0035] According to the present invention, "at least one alcohol containing one or two hydroxyl groups" means that one or more alcohols containing one or two hydroxyl groups can be used.

[0036] The alcohol (AO) can be a monoalcohol (MO) containing one hydroxyl group, a diol (D) containing two hydroxyl groups, or a mixture of a monoalcohol (MO) and a diol (D).

[0037] When the alcohol (AO) is a monoalcohol (MO), the monoalcohol (MO) can be an aliphatic monoalcohol or an aromatic monoalcohol.

[0038] The monoalcohol (MO) is preferably characterized by a boiling point at atmospheric pressure of at least 90 °C, preferably at least 100 °C, more preferably at least 125 °C, and most preferably at least 150 °C.

[0039] When the monoalcohol (MO) is an aliphatic monoalcohol, the monoalcohol (MO) preferably has the following formula: R Hm -OH (Formula MO-1) (wherein R Hm is a monovalent aliphatic group having one or more carbon atoms, particularly one or more carbon atoms) is an aliphatic monoalcohol.

[0040] Generally, it is understood that better results are obtained with long-chain aliphatic monoalcohols, i.e., aliphatic monoalcohols (MO) having a total number of carbon atoms preferably of at least 6. The aliphatic monoalcohol (MO) preferably has 6 to 36 carbon atoms, more preferably 6 to 24 carbon atoms.

[0041] Among the aliphatic monoalcohols (MO) that can be advantageously used in the present invention, in particular, hexanol-1 [CH3(CH2)5OH], dodecanol [H3C-(CH2) 11-OH], hexadecanol or cetyl alcohol [H3C-(CH2) 15 -OH], octadecanol or stearyl alcohol [H3C-(CH2) 17 -OH], arachidyl alcohol [H3C-(CH2) 18 -COOH], docosanol or behenyl alcohol [H3C-(CH2) 21 -OH], cyclohexanol and menthol can be mentioned.

[0042] When the monoalcohol (MO) is an aromatic monoalcohol, the aromatic monoalcohol (MO) is preferably selected from the group consisting of phenol, cresol, naphthol, benzyl alcohol, 2-phenylethanol and 3-phenylpropanol.

[0043] The monoalcohol (MO) is preferably dodecanol, benzyl alcohol, menthol and mixtures thereof.

[0044] When the alcohol (AO) is a diol (D), the diol (D) is preferably characterized by a boiling point at atmospheric pressure of at least 100 °C, preferably at least 150 °C, more preferably at least 200 °C, most preferably at least 230 °C.

[0045] Non-limiting examples of the diol (D) include, inter alia, ethylene glycol, 2,2-dimethylpropane-1,3-diol, pentane-1,2-diol, pentane-1,5-diol, hexane-1,2-diol, heptane-1,2-diol, diethylene glycol, hexane-1,6-diol, heptane-1,7-diol, 1,4-cyclohexanediol, cis 1,2-cyclohexanediol, trans 1,2-cyclohexanediol, polyether polyol diol Dianol® 220, 1,4-cyclohexanedimethanol, isosorbide, isoidide, dodecane 1,12-diol and mixtures thereof.

[0046] The diol (D) is preferably selected from diethylene glycol, 1,4-cyclohexanedimethanol, isosorbide, isoidide, dodecane 1,12-diol, and mixtures thereof.

[0047] The diol (D) is more preferably selected from diethylene glycol, 1,4-cyclohexanedimethanol, and mixtures thereof.

[0048] The diol (D) that has been shown to provide particularly good results is thus 1,4-cyclohexanedimethanol, which is most particularly preferred, and a cis / trans isomer mixture of 1,4-cyclohexanedimethanol (CAS number 105-08-8) is very particularly preferred.

[0049] The alcohol (AO) is preferably selected from diethylene glycol, 1,4-cyclohexanedimethanol, isosorbide, isoidide, dodecane 1,12-diol, dodecanol, benzyl alcohol, menthol, and mixtures thereof.

[0050] The alcohol (AO) is more preferably the diol (D) (more preferably selected from diethylene glycol, 1,4-cyclohexanedimethanol, and mixtures thereof), and the diol (D) is preferably characterized by its boiling point at atmospheric pressure as defined above and / or the diol (D) is preferably used in an amount as defined below.

[0051] The alcohol (AO) is used in an amount such that the number of its hydroxyl groups is preferably included in the range of 0.010 to 0.750% relative to the total number of carboxylic acid groups of glycolic acid and, when present, hydroxy acid (A).

[0052] Alcohol (AO) is used in an amount such that the number of its hydroxyl groups is preferably at least 0.010%, preferably at least 0.050%, more preferably at least 0.080%, most preferably at least 0.100% and / or preferably at most 0.750%, preferably at most 0.700%, more preferably at most 0.650% with respect to the total number of carboxylic acid groups of glycolic acid and, if present, hydroxy acid (A).

[0053] It has been found that an amount of alcohol (AO) such that the number of its hydroxyl groups is 0.010 to 0.650% with respect to the total number of carboxylic acid groups of glycolic acid and, if present, hydroxy acid (A) is particularly useful according to a preferred embodiment of the present invention.

[0054] Polyol (H) and alcohol (AO) are used in an amount such that the total number of moles of its hydroxyl groups minus the total number of moles of carboxylic acid groups of glycolic acid and, if present, hydroxy acid (A), divided by the total number of moles of carboxylic acid groups of glycolic acid and, if present, hydroxy acid (A), is preferably from 0 to 1%, preferably from 0.1 to 1%, more preferably from 0.3 to 0.9%.

[0055] Monocarboxylic acid (C) contains one carboxylic acid group, i.e., one carboxylic acid group covalently bonded to the carbon atom of monocarboxylic acid (C).

[0056] The selection of monocarboxylic acid (C) is not particularly limited. Monocarboxylic acid (C) can be an aliphatic monocarboxylic acid or an aromatic monocarboxylic acid.

[0057] When monocarboxylic acid (C) is an aliphatic monocarboxylic acid, monocarboxylic acid (C) preferably has the following formula: R Hm -COOH (Formula C-1) (wherein R Hm is a monovalent aliphatic group having one or more carbon atoms, particularly having three or more carbon atoms) is an aliphatic monocarboxylic acid.

[0058] Better results are generally understood to be obtained with long-chain aliphatic monocarboxylic acids, i.e., aliphatic monocarboxylic acids (C) having a total number of carbon atoms advantageously of at least 4, preferably at least 5, more preferably at least 6. The aliphatic monocarboxylic acid (C) preferably has from 4 to 36 carbon atoms, more preferably from 6 to 24 carbon atoms.

[0059] Among the aliphatic monocarboxylic acids (C) that can be advantageously used in the present invention, in particular, caprylic acid [CH3(CH2)6COOH], capric acid [CH3(CH2)8COOH], undecanoic acid [H3C-(CH2)9-COOH], dodecanoic acid or lauric acid [H3C-(CH2) 10 -COOH], tridecanoic acid [H3C-(CH2) 11 -COOH], tetradecanoic acid or myristic acid [H3C-(CH2) 12 -COOH], pentadecanoic acid [H3C-(CH2) 13 -COOH], hexadecanoic acid or palmitic acid [H3C-(CH2) 14 -COOH], octadecanoic acid or stearic acid [H3C-(CH2) 16 -COOH], arachidic acid [H3C-(CH2) 18 -COOH], and behenic acid [H3C-(CH2) 20 -COOH] can be mentioned.

[0060] The aliphatic monocarboxylic acid (C) that has been shown to provide particularly good results is stearic acid, and for this reason it is particularly preferred.

[0061] When the monocarboxylic acid (C) is an aromatic monocarboxylic acid, the monocarboxylic acid (C) is advantageously selected from the group consisting of benzoic acid, naphthoic acid and phenylacetic acid.

[0062] The polymer (PGA) according to the present invention is characterized in particular in that the monocarboxylic acid (C) is an aliphatic monocarboxylic acid of the formula: RH m -COOH (Formula C-1), or an aromatic monocarboxylic acid selected from the group consisting of benzoic acid, naphthoic acid and phenylacetic acid.

[0063] When present, monoacid (C) is preferably an aromatic monoacid.

[0064] When present, monoacid (C) is used in an amount such that the number of its carboxylic acid groups is preferably included in the range of 0.010 to 2.0% relative to the total number of hydroxyl groups of glycolic acid and, when present, hydroxyacid (A).

[0065] Monoacid (C) is used in an amount such that the number of its carboxylic acid groups is preferably at least 0.010%, more preferably at least 0.030%, still more preferably at least 0.075% relative to the total number of hydroxyl groups of glycolic acid and, when present, hydroxyacid (A); and / or preferably at most 2.0%, more preferably at most 1.50%, still more preferably at most 1.20%, most preferably at most 1.00%, even most preferably at most 0.75% relative to the total number of hydroxyl groups of glycolic acid and, when present, hydroxyacid (A).

[0066] The polymer (PGA) according to the present invention is particularly · the amount of polyol (H) is such that the number of its hydroxyl groups is included in the range of 0.050 to 1.200% relative to the total number of carboxyl groups of glycolic acid and, when present, hydroxyacid (A); · the amount of alcohol (AO) is such that the number of its hydroxyl groups is included in the range of 0.010 to 0.750% relative to the total number of carboxyl groups of glycolic acid and, when present, hydroxyacid (A); · when present, the amount of monoacid (C) is such that the number of its carboxylic acid groups is included in the range of 0.010 to 2.0% relative to the total number of hydroxyl groups of glycolic acid and, when present, hydroxyacid (A) which is characterized by.

[0067] Polyacid (O) contains at least two carboxylic acid groups, i.e., at least two carboxylic acid groups covalently bonded to the carbon atoms of polyacid (O).

[0068] Polyacid (O) can contain two carboxylic acid groups [dicarboxylic acid (DA)] or three or more carboxylic acid groups, particularly three or four carboxylic acid groups [tricarboxylic acid / tetracarboxylic acid (TTA)].

[0069] Dicarboxylic acid (DA) preferably contains two carboxylic acid groups, i.e., two carboxylic acid groups covalently bonded to the carbon atoms of the dicarboxylic acid (DA).

[0070] Dicarboxylic acid (DA) can be an aliphatic linear dicarboxylic acid or an aromatic dicarboxylic acid.

[0071] Dicarboxylic acid (DA) is preferably an aromatic dicarboxylic acid.

[0072] Non-limiting examples of aromatic dicarboxylic acids (DA) include, inter alia, phthalic acids such as isophthalic acid (IA) and terephthalic acid (TA), 2,5-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, 2,2-bis(4-carboxyphenyl)propane, bis(4-carboxyphenyl)methane, 2,2-bis(4-carboxyphenyl)hexafluoropropane, 2,2-bis(4-carboxyphenyl)ketone, 4,4'-bis(4-carboxyphenyl)sulfone, 2,2-bis(3-carboxyphenyl)propane, bis(3-carboxyphenyl)methane, 2,2-bis(3-carboxyphenyl)hexafluoropropane, 2,2-bis(3-carboxyphenyl)ketone, bis(3-carboxyphenoxy)benzene, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, etc., naphthalenedicarboxylic acids.

[0073] Phthalic acid is generally preferred.

[0074] The dicarboxylic acid (DA) that has been shown to provide particularly good results is isophthalic acid, and thus it is particularly preferred.

[0075] The triacid / tetraacid (TTA) preferably contains three or four carboxylic acid groups, i.e., three or four carboxylic acid groups covalently bonded to the carbon atoms of the triacid / tetraacid (TTA).

[0076] The triacid / tetraacid (TTA) can be selected from aliphatic polycarboxylic acids, alicyclic polycarboxylic acids, and aromatic polycarboxylic acids, all of which contain three or four carboxylic acid groups.

[0077] Examples of aliphatic polycarboxylic acids containing three or four carboxylic acid groups are: - Propane 1,2,3-tricarboxylic acid (also known as tricarballylic acid); - Ethane-1,1,2,2 tetracarboxylic acid; - Butane-1,2,3,4 tetracarboxylic acid; - Pentane-1,2,4,5-tetracarboxylic acid That's it.

[0078] Among them, tricarballylic acid and butane-1,2,3,4 tetracarboxylic acid are preferred.

[0079] Examples of alicyclic polycarboxylic acids containing three or four carboxylic acid groups are: - 1,2,3,4-Cyclobutanetetracarboxylic acid; - 2,2,6,6-Tetra-(carboxyethyl)cyclohexanone; - (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic acid; - Cyclopentane-1,2,3,4 tetracarboxylic acid; - Cyclohexane-1,2,4,5 tetracarboxylic acid; - Cyclohexane-2,3,5,6 tetracarboxylic acid; - 3-Ethylcyclohexane-1,2,4,5 tetracarboxylic acid; - 1-Methyl-3-ethylcyclohexane-3-(1,2)5,6 tetracarboxylic acid; - 1-Ethylcyclohexane-1-(1,2),3,4 tetracarboxylic acid; - 1-Propylcyclohexane-1-(2,3),3,4-tetracarboxylic acid; - 1,3-Dipropylcyclohexane-1-(2,3),3-(2,3)-tetracarboxylic acid; - Dicyclohexyl-3,4,3’,4’-tetracarboxylic acid is.

[0080] Examples of aromatic polycarboxylic acids containing three or four carboxylic acid groups are: - Pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid); - Trimesic acid (1,3,5-benzenetricarboxylic acid); - Trimellitic acid (1,3,4-benzenetricarboxylic acid); - Benzophenone-3,3’,4,4’-tetracarboxylic acid; - Tetrahydrofuran-2,3,4,5-tetracarboxylic acid; - 4,4’-(Hexafluoroisopropylidene)diphthalic acid; - 4,4’-Oxydiphthalic anhydride; - 4,4’-(4,4’-Isopropylidenediphenoxy)bis(phthalic acid); - 3,3’,4,4’-Biphenyltetracarboxylic acid; - 2,3,3’,4’-Biphenyltetracarboxylic acid; - 2,2’,3,3’-Biphenyltetracarboxylic acid; - 1,2,5,6-Naphthalenetetracarboxylic acid; - 2,3,6,7-Naphthalenetetracarboxylic acid; - Perylene-3,4,9,10-tetracarboxylic acid; - Propane 2,2-bis(3,4-dicarboxyphenyl) acid; - Ethane 1,1-bis(2,3-dicarboxyphenyl) acid; - Ethane 1,1-bis(3,4-dicarboxyphenyl) acid; - Phenanthrene-1,8,9,10-tetracarboxylic acid; - Tetrahydrofuran-2,3,4,5-tetracarboxylic acid; - 3,3’,4,4’-Benzophenone tetracarboxylic acid; - 2,2’,3,3’-Benzophenone tetracarboxylic acid; - 2,3,5,6-Pyridine tetracarboxylic acid; - 3,3’,4,4’-Tetraphenylsilane tetracarboxylic acid; - 2,2’-Bis(3,4-biscarboxyphenyl)hexafluoropropane tetracarboxylic acid; - 2,2-Bis(3,4-dicarboxyphenyl)sulfonic acid; - 4,4’-(Hexafluoroisopropylidene)diphthalic acid; - 3,3’,4,4’-Diphenylsulfone tetracarboxylic acid; - Ethylene glycol bistrimellitic acid; - Hydroquinone diphthalic acid; - Pyrazine-2,3,5,6-tetracarboxylic acid; - Thiophene-2,3,4,5-tetracarboxylic acid is.

[0081] Among them, 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid) is preferred.

[0082] Preferred triacids / tetracids (TTA) are tricarballylic acid, 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid) and butane-1,2,3,4-tetracarboxylic acid, and tricarballylic acid is particularly preferred.

[0083] The polyacid (O) is preferably an aromatic diacid (DA), more preferably phthalic acid, and most preferably isophthalic acid.

[0084] When present, the polyacid (O) is used in an amount such that the number of its carboxylic acid groups is included in the range of 0.025 to 0.900% relative to the total number of hydroxyl groups of glycolic acid and, when present, hydroxy acid (A).

[0085] When present, the polyacid (O) is advantageously at least 0.025%, preferably at least 0.050%, more preferably at least 0.100% and / or advantageously at most 0.900%, preferably at most 0.800%, more preferably at most 0.750%, most preferably at most 0.650%, particularly most preferably at most 0.600% in terms of the number of its carboxylic acid groups relative to the total number of hydroxyl groups of glycolic acid and, when present, hydroxyacid (A). It is used in such an amount.

[0086] When present, an amount of polyacid (O) such that the number of its carboxyl groups is 0.150 to 0.550% relative to the total number of hydroxyl groups of glycolic acid and, when present, hydroxyacid (A) has been found to be particularly useful according to a preferred embodiment of the present invention.

[0087] Polymer (PGA) has a melt viscosity in the range of preferably 300 to 1500 Pa·s when measured according to ASTM D4440-08 at a shear rate of 10 s -1 and a temperature of 260°C. Polymer (PGA) has a melt viscosity of preferably at least 300, more preferably at least 400, even more preferably at least 500 Pa·s when measured according to ASTM D4440-08 at a shear rate of 10 s -1 and a temperature of 260°C. Polymer (PGA) has a melt viscosity of preferably at most 1500, more preferably at most 1200, even more preferably at most 1000 Pa·s when measured according to ASTM D4440-08 at a shear rate of 10 s -1 and a temperature of 260°C.

[0088] Polymer (PGA), which has been found to have particularly advantageous properties, has a melt viscosity in the range of 500 to 1000 Pa·s when measured according to ASTM D4440-08 at a shear rate of 10 s -1 and a temperature of 260°C.

[0089] Advantageously, therefore, the polymer (PGA) has a melt viscosity η of 300 to 1500 Pa·s when measured according to ASTM D4440-08 at a shear rate of greater than 0.5, preferably greater than 1.0, more preferably greater than 1.3, and at a temperature of 260 °C for 10 seconds -1 seconds 10 and has a tan δ in the domain of -1 seconds 10 seconds -1 .

[0090] The present invention further relates to a method for producing a polymer (PGA) as detailed above, the method comprising the step of polycondensing glycolic acid (GA), optionally at least one hydroxy acid (A), at least one polyol (H), at least one alcohol (AO), optionally at least one monocarboxylic acid (C) and optionally at least one polycarboxylic acid (O) as detailed above

[0091] In the method of the present invention, a polycondensation catalyst may optionally be added to the monomer mixture

[0092] Such polycondensation catalysts are well known to those skilled in the art and may be selected, for example, from tin(II) chloride, stannous octoate, zinc acetate, zinc lactate, methanesulfonic acid, orthophosphoric acid and mixtures thereof. Methanesulfonic acid and mixtures of methanesulfonic acid with other catalysts, those disclosed above or others, are particularly preferred

[0093] When added, such catalysts are usually added in an amount of about 0.001 to 2 mol%, particularly about 0.002 to 0.1 mol%, based on the total moles of monomers in the monomer mixture

[0094] Preferably, the polycondensation step is carried out at least in part at a temperature such that the monomer mixture and the growing polymer formed are in the molten phase. Generally, after the step of providing a prepolymer by polycondensing in the molten state unreacted GA, hydroxy acid (A) (if present), polyol (H), alcohol (AO), monoacid (C) (if present) and polyacid (if present) as the case may be, the polycondensation then continues at a temperature such that the prepolymer is in the solid state (this step is hereinafter referred to in this specification as solid state polymerization or SSP).

[0095] Therefore, the process of the present invention generally includes a first step of polymerization in the molten state to form a prepolymer and a second step of solid state polymerization (SSP) to increase the molecular weight of the prepolymer.

[0096] In the first step, the temperature is selected to maintain the monomer mixture and, as the reaction proceeds, the prepolymer formed in the molten state.

[0097] Generally, the first step of polycondensation in the molten state is achieved under stirring by maintaining the reaction mixture at a temperature in the range of 160 to 240 °C; the temperature can be kept constant throughout this first step or changed and maintained at two or more temperature plateaus. According to the present invention, the expression "temperature plateau" means that the temperature is kept substantially constant for at least 5 minutes.

[0098] In the process of the present invention, the prepolymer, optionally containing residual monomers, as detailed above, obtained from the first step of polymerization in the molten state, is subjected to a step of solidification and size reduction to provide a particulate prepolymer material in the form of discrete particles.

[0099] The particulate prepolymer can be processed from the molten state in the form of beads or pellets by standard techniques of pelletization and / or tableting, or recovered as solidified fragments and milled to provide a powder.

[0100] The pelletization technique is generally based on extrusion. On the other hand, the molten prepolymer, which may contain residual monomers as detailed above, is generally pushed through a die that generally contains a plurality of holes for generating strands of the material, optionally using a gear pump. The strands are then cut into cylinders of a given length by a suitable cutting system (e.g., a rotating blade) and solidified by cooling.

[0101] The tabletization technique involves feeding the molten prepolymer, which may contain residual monomers as detailed above, from a container, pit or supply pipe system, optionally using a gear pump, to a droplet forming device, and depositing droplets of the molten prepolymer on a conveyor belt. However, the droplets solidify in the form of tablets, for example having a size in the range of 1 to 25 mm in diameter.

[0102] When recovering the prepolymer, which may contain residual monomers as detailed above, in the form of fragments by solidification, a milling step is required. Such a milling step can be carried out by any means known to those skilled in the art, for example by milling with a high-speed grinder or a rotary mill.

[0103] The SSP process can be carried out by exposing the prepolymer, which may contain residual monomers as detailed above, in its solid state, either under vacuum or in an inert gas atmosphere (e.g., under nitrogen), or both, for at least 1 hour or even for several days, to a temperature above the glass transition temperature of the prepolymer, which may contain residual monomers as detailed above, but below its melting temperature. Typically, such an SSP process can be carried out at a temperature of 140 to 240 °C, particularly 150 to 230 °C, for example about 170 to 220 °C and at a pressure of less than 50 mbar.

[0104] Depending on the nature of the residual monomers in the prepolymer, their proportions, the target final viscosity / molecular weight, the temperature and pressure during the overall polycondensation process, the duration of the SSP process can be from 2, 3 hours to 1 week, particularly from 6 to 200 hours, for example about 10 to 150 hours.

[0105] Preferably, the polycondensation reaction in the melt phase is carried out under vacuum to evaporate the water of reaction and prevent the water from hydrolyzing the polymer chains being formed. Very particularly preferably, the polycondensation reaction in the melt phase is started at atmospheric pressure and the pressure is gradually reduced until a pressure of the order of a few millibars, particularly less than 50 millibars, for example less than 20 millibars is achieved. The SSP process is typically carried out at a pressure of about 0.1 to 50 millibars, preferably about 0.1 to 20 millibars.

[0106] In the process of the present invention, an antioxidant can optionally be added to the reaction medium. Preferably, such an antioxidant is added between the melt phase polycondensation process and the SPP process. Such an antioxidant is typically added in an amount of about 0.01 to 1% by weight, particularly 0.1 to 0.5% by weight, of the monomer mixture. Such antioxidants are well known to those skilled in the art and can be selected, for example, from hindered phenols and hindered phosphites.

[0107] Furthermore, the present invention relates to a composition (C) comprising a polymer (PGA) and at least one additional raw material. Generally, the composition comprises a major amount of the polymer (PGA) and a minor amount of any other additional raw materials as described above. Said raw materials are selected, inter alia, from antioxidants, heat stabilizers, buffers, UV and light stabilizers, pigments, lubricants, processing aids, hydrolysis stabilizers, reinforcing agents, strengthening agents, plasticizers, colorants, antistatic agents, flame retardants, nucleating agents and other processing aids. It is also possible for composition (C) to contain one or more additional glycolic acid polymers different from the polymer (PGA) as detailed above. For example, the polymer (PGA) of the present invention can be mixed with a linear PGA polymer obtained from ring-opening polycondensation of glycolic acid in the absence of any polyfunctional modified monomers, or can be mixed with another branched glycolic acid-based polymer different from the polymer (PGA) of the present invention.

[0108] The amount of said raw materials is generally included in an amount of 0.01 to 65% by weight, preferably 0.1 to 60% by weight, more preferably 0.1 to 50% by weight, based on the total weight of composition (C). For embodiments where composition (C) containing polymer (PGA) does not contain any additional glycolic acid polymers different from the polymer (PGA) of the present invention, the additional raw materials as described above are generally included in an amount of 0.01 to 65% by weight, preferably 0.1 to 60% by weight, more preferably 0.1 to 50% by weight, based on the total weight of composition (C).

[0109] A wide selection of reinforcing agents, also called reinforcing fibers or reinforcing fillers, can be added to the composition according to the present invention. They can be selected from fiber reinforcing agents and particulate reinforcing agents.

[0110] Fiber reinforcing fillers are considered herein to be materials having length, width and thickness, where the average length is significantly greater than both the width and the thickness. Generally, such materials advantageously have an aspect ratio defined as the average ratio between the length and the largest of the width and the thickness of at least 5, preferably at least 10, more preferably at least 20, most preferably at least 50.

[0111] In some embodiments, the reinforcing fibers (preferably glass fibers) have an average length of 3 to 50 mm. In some such embodiments, the reinforcing fibers advantageously have an average length of 3 to 10 mm, preferably 3 to 8 mm, more preferably 3 to 6 mm, and most preferably 3 to 5 mm. In alternative embodiments, the reinforcing fibers advantageously have an average length of 10 to 50 mm, preferably 10 to 45 mm, more preferably 10 to 35 mm, particularly more preferably 10 to 30 mm, most preferably 10 to 25 mm, and particularly most preferably 15 to 25 mm. The average length of the reinforcing fibers can be considered as the average length of the reinforcing fibers before incorporation into the composition (C), or as the average length of the reinforcing fibers in the composition (C).

[0112] The reinforcing filler can be selected from mineral fillers (such as talc, mica, kaolin, calcium carbonate, calcium silicate, magnesium carbonate, etc.), glass fibers, carbon fibers, synthetic polymer fibers, aramid fibers, aluminum fibers, titanium fibers, magnesium fibers, boron carbide fibers, rock wool fibers, steel fibers, and wollastonite.

[0113] Among the reinforcing fillers, glass fibers are preferred, and chopped strand A-, E-, C-, D-, S-, and R-glass fibers as described in Chapter 5.2.3, pages 43 - 48 of Additives for Plastics Handbook, 2nd edition, John Murphy are preferred. Preferably, the filler is selected from fiber fillers. More preferably, it is a reinforcing fiber capable of withstanding high-temperature applications.

[0114] The reinforcing agent can be present in the composition (C) in a total amount that is advantageously more than 10% by weight, preferably more than 20% by weight, more preferably more than 25% by weight, and most preferably more than 30% by weight, based on the total weight of the composition (C). The reinforcing agent can be present in the composition (C) in a total amount that is advantageously less than 65% by weight, preferably less than 60% by weight, more preferably less than 55% by weight, and most preferably less than 50% by weight, based on the total weight of the composition (C).

[0115] The composition (C) of the present invention may also contain a reinforcing agent. The reinforcing agent generally has a low Tg, which is preferably less than room temperature, more preferably less than 0 °C, and even more preferably less than -25 °C. As a result of its low Tg, the reinforcing agent is typically elastomeric at room temperature.

[0116] The reinforcing agent can be a functionalized polymer backbone. The polymer backbone of the reinforcing agent can be selected from polyethylene and its copolymers, such as ethylene-butene, ethylene-octene; polypropylene and its copolymers; polybutene; polyisoprene; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-acrylate rubber; butadiene-acrylonitrile rubber; ethylene-acrylic acid (EAA); ethylene-vinyl acetate (EVA); acrylonitrile-butadiene-styrene rubber (ABS); block copolymer styrene ethylene butadiene styrene (SEBS); block copolymer styrene butadiene styrene (SBS); methacrylate-butadiene-styrene (MBS) type core-shell elastomer; or an elastomeric backbone containing one or more of the above mixtures.

[0117] When the reinforcing agent is functionalized, the functionalization of the main chain can result from the copolymerization of monomers containing functional groups or from the grafting of the polymer main chain with additional components.

[0118] Specific examples of the functionalized reinforcing agent include, among others, a terpolymer of ethylene, an acrylate ester, and glycidyl methacrylate; a copolymer of ethylene and butyl acrylate; a copolymer of ethylene, butyl acrylate, and glycidyl methacrylate; an ethylene-maleic anhydride copolymer; EPR grafted with maleic anhydride; a styrene copolymer grafted with maleic anhydride; an SEBS copolymer grafted with maleic anhydride; a styrene-acrylonitrile copolymer grafted with maleic anhydride or an ABS copolymer grafted with maleic anhydride.

[0119] The reinforcing agent may be present in the composition (C) in a total amount of preferably more than 1% by weight, more preferably more than 2% by weight, still more preferably more than 3% by weight, based on the total weight of the composition (C). The reinforcing agent may be present in the composition (C) in a total amount of preferably less than 30% by weight, more preferably less than 20% by weight, still more preferably less than 15% by weight, and most preferably less than 10% by weight, based on the total weight of the polymer composition (C).

[0120] Particularly preferred is a composition (C) comprising the polymer (PGA) according to the invention as defined above and, based on the total weight of the composition (C), 10 to 60% by weight of a reinforcing filler, preferably glass fibers. Even more particularly preferred is a composition comprising the polymer (PGA) according to the invention as defined above and, based on the total weight of the composition (C), 20 to 50% by weight of a reinforcing agent, preferably glass fibers. Such a composition (C) may also contain other raw materials, preferably one or more reinforcing agents.

[0121] Most particularly preferred is a composition (C) consisting of the polymer (PGA) according to the invention as defined above and, based on the total weight of the composition (C), 10 to 60% by weight, preferably 20 to 50% by weight, of a reinforcing agent, preferably glass fibers.

[0122] The present invention further relates to a method for manufacturing a multilayer, optionally stretched, optionally thermoformed product, said method comprising: (i) forming by processing from the melt a multilayer resin laminate comprising at least one layer of a polymer (PGA) as detailed above or of a composition (C) comprising a polymer (PGA) as detailed above and at least one layer of a thermoplastic different from the polymer (PGA); (ii) optionally stretching the multilayer resin laminate; (iii) optionally thermoforming the optionally stretched laminate to produce a multilayer, optionally stretched, optionally thermoformed product and relates to a method comprising the steps.

[0123] The selection of the thermoplastic is not particularly limited, provided that it can be laminated, co-extruded or co-injected with a layer made of or containing the polymer (PGA).

[0124] Preferred examples of such thermoplastics include: polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polystyrene resins, acrylic acid or methacrylic acid resins, nylon resins, sulfide resins such as polyphenylene sulfide, polycarbonate resins, functionalized tie layer resins, adhesives and polyolefins. Among these, it is preferable to use polyester resins, particularly aromatic polyester resins composed of a diol component and a dicarboxylic acid component, and at least one of them, particularly the dicarboxylic acid component, is an aromatic component in order to provide a multilayer product that satisfies transparency and gas barrier properties in combination according to its use. Polyethylene terephthalate (PET) is particularly preferred.

[0125] The multilayer resin laminate can be of any shape or form; it can be, inter alia, in the form of a tubular laminate such as a parison, a flat laminate, a thermoformed laminate or a formed container.

[0126] A preferred example of the multilayer resin laminate is a bottle preform including a screw-on (neck) and a closed-end cylindrical body.

[0127] A bottle preform such as a multilayer resin laminate advantageously includes at least one layer of the polymer (PGA) as detailed above or of the composition (C) containing the polymer (PGA) as detailed above and at least one layer of a thermoplastic different from the polymer (PGA), thus forming a multilayer structure.

[0128] The bottle preform can include a multilayer structure throughout the cylindrical-shaped body, i.e., on its sidewall and also at the closed end of the molded body, i.e., on its bottom wall (usually called a "closed dome bottle preform"), or can include a multilayer structure only throughout the cylindrical-shaped body, i.e., only on its sidewall, thus leaving the closed end of the molded body, i.e., the bottom wall, as at least one layer of a thermoplastic different from the polymer (PGA) (usually called an "open dome bottle preform").

[0129] Bottles formed from either an open dome or a closed dome bottle preform advantageously maintain a similar gas barrier property with a similar barrier loading. However, bottles formed from an open dome bottle preform advantageously exhibit improved delamination resistance at the bottom of the bottle. This is advantageous since most delamination occurs at the bottom of the bottle both in the short term and in the long term.

[0130] The open dome bottle preform is particularly preferred.

[0131] In an open dome bottle preform, the multilayer structure can be included throughout the entire cylindrical body, i.e., on its sidewall, or can be limited to only a part of the cylindrical body.

[0132] In an open dome bottle preform, the polymer (PGA) layer inside the bottle preform advantageously exhibits at least 20%, preferably at least 50%, more preferably at least 70%, and most preferably at least 90% of the height of the cylindrical body.

[0133] According to a very most preferred embodiment, the multilayer structure is included in the open dome bottle preform throughout the entire (100%) cylindrical body, i.e., on its sidewall.

[0134] The bottle preform can advantageously also include a multilayer structure in its neck, without adversely affecting the barrier performance. Preferably, the bottle preform does not include a multilayer structure in its neck.

[0135] The step of forming the resin laminate can be carried out by any technique including processing a polymer (PGA) or a composition containing the polymer (PGA) and a thermoplastic while they are in a molten state.

[0136] Suitable preferred techniques are coextrusion molding and co-injection molding.

[0137] According to the coextrusion molding technique, the melt streams of the polymer (PGA) or the composition containing the polymer (PGA) and the thermoplastic are generated in a dedicated screw extruder and fed to a multiple slot die to provide a multilayer resin laminate.

[0138] In the injection molding technique, the melt shots of the polymer (PGA) or the composition containing the polymer (PGA) and the thermoplastic are injected into the same mold through a multi-shot nozzle.

[0139] In an optional step (ii), the multilayer resin laminate is stretched at a temperature generally enabling plastic deformation, a temperature generally exceeding the crystallization temperature.

[0140] According to a particular embodiment, the multilayer resin laminate is cooled and solidified after step (i) and before undergoing step (ii). In this case, step (ii) includes the step of reheating the multilayer laminate to a temperature exceeding the glass transition temperature of the polymer (PGA) and the thermoplastic, and the multilayer laminate is stretched while being heated. The stretching can be achieved by blowing a pressurized gas, typically air; the stretching step can be carried out in a mold that forces the multilayer stretched product to adhere to a well-defined shape using a tenter frame.

[0141] According to other embodiments, the multilayer resin laminate is subjected to step (ii) without any intermediate cooling and reheating steps.

[0142] According to certain embodiments of this variation, for example, an extruded multilayer resin laminate in the form of a parison can be blown using compressed air directly as it is extruded from the die and while in the molten phase.

[0143] According to certain embodiments of this variation, for example, an extruded multilayer resin laminate in the form of a film can be stretched, for example, uniaxially or biaxially using suitable stretching means operating in the longitudinal and / or transverse directions.

[0144] According to these embodiments, the multilayer stretched product can be, inter alia, a multilayer inflation film (stretched in the molten phase), a multilayer cast film or a multilayer shrink film produced by the double bubble process.

[0145] The present invention further relates to an article, preferably a molded article or a multilayer optionally stretched and optionally thermoformed product obtained by a method as detailed above, comprising a polymer (PGA) according to the present invention and a composition (C) according to the present invention.

[0146] The article according to the present invention is preferably a bottle, preferably an open dome bottle, an article for hydrocarbon resource recovery, a packaging film, a sanitary article, a disposable pod, a structural component for electronic applications or a biomedical article.

[0147] The bottle advantageously comprises a polymer (PGA) according to the present invention or a composition (C) according to the present invention or a multilayer stretched product obtained by a method as detailed above.

[0148] The bottle is preferably a bottle used for carbonated soft drinks, soda water or juice.

[0149] The bottle can be a closed dome bottle or an open dome bottle formed from a corresponding bottle preform as described above, preferably an open dome bottle. The details and preferences described above for the bottle preform are the same for the bottle according to the present invention.

[0150] Articles for hydrocarbon resource recovery advantageously include the polymer (PGA) according to the present invention or the composition (C) according to the present invention.

[0151] Articles for hydrocarbon resource recovery (such as oil / shale oil or natural gas / shale gas, often referred to as petroleum gas) are preferably downhole tools, downhole tool members or elements of downhole tool members.

[0152] According to the present invention, a "downhole tool" means a tool used to form a downhole (which may be referred to as a "wellbore" or "borehole") provided during the drilling of an oil well towards a production reservoir for obtaining hydrocarbon resources such as oil, shale oil, etc., and natural gas such as shale gas from the ground (including above water), and for recovering hydrocarbon resources after the completion of the oil well.

[0153] A downhole tool, downhole tool member or element of a downhole tool member advantageously refers to a component of oilfield equipment used during drilling, completion or repair of a downhole, and includes tools used to act on the closure and fracturing of a borehole.

[0154] A downhole tool, downhole tool member or element of a downhole tool member is preferably selected from the group consisting of a frac plug or a dissolvable plug, a bridge plug, a cement retainer, a perforating gum, a ball seal, a frac ball, a diverting ball, a ball sheet, a mandrel, slips, wedges, rings, a sealing plug, a flux sleeve, a fracturing sleeve piston (also known as a "piston" or "piston plug") and a packer.

[0155] One or more components of a downhole tool or of a downhole tool member or of an element of a downhole tool member can be made of a polymer (PGA) according to the invention or of a composition (C) according to the invention. Alternatively, the whole of their structure can be made of a polymer (PGA) according to the invention or of a composition (C) according to the invention.

[0156] The downhole tool or downhole tool member or element of a downhole tool member according to the invention can be manufactured using known melt processing techniques such as injection molding, extrusion or any other molding or thermoforming technique.

[0157] The packaging film advantageously comprises a polymer (PGA) according to the invention or a composition (C) according to the invention.

[0158] The packaging film is preferably selected from the group consisting of flexible packaging films, shrink wraps (also called shrinkable films) and snack packages, and from rigid multilayer sheets (flat and thermoformed).

[0159] The sanitary articles advantageously comprise a polymer (PGA) according to the invention or a composition (C) according to the invention.

[0160] The sanitary articles are preferably selected from the group consisting of tampon applicators and feminine wipes.

[0161] The disposable pods advantageously comprise a polymer (PGA) according to the invention or a composition (C) according to the invention.

[0162] The disposable pods are preferably selected from the group consisting of coffee pods and K-cups.

[0163] The structural parts for electronic applications advantageously comprise a polymer (PGA) according to the invention or a composition (C) according to the invention.

[0164] The structural parts for electronic applications are preferably selected from the group consisting of a frame, a support member, and a protective case.

[0165] The biomedical articles advantageously contain the polymer (PGA) according to the invention or the composition (C) according to the invention.

[0166] The biomedical articles are preferably selected from the group consisting of surgical sutures, surgical meshes, bone growth support materials, and implants.

[0167] The articles according to the invention are more preferably bottles, preferably open-dome bottles, articles for hydrocarbon resource recovery, or sanitary articles.

[0168] If the disclosure of any patent, patent application, and publication incorporated herein by reference conflicts with the description of this application to the extent that it may obscure the terms, the description shall control.

[0169] The present invention will now be described in more detail in connection with the following examples, which are for illustrative purposes only and are not intended to limit the scope of the invention.

[0170] Method for measuring the residual methanesulfonic acid content in PGA Approximately 0.1 g of PGA was weighed into a 50 ml polypropylene autosampler tube, dissolved in 5 ml of concentrated nitric acid, and heated at 95 °C in a heating block. Subsequently, prior to the addition of the standard solution Sc 1 g / l (used as an internal standard), the solution was made up to 50 ml with ultrapure water and shaken. Two replicates of each sample were prepared.

[0171] This solution was then measured by inductively coupled plasma optical emission spectrometry (ICP-OES) against a series of calibration solutions containing increasing amounts of S, and the Sc standard and nitric acid at the same concentration as the sample were also measured. The instrument software automatically calculated the S concentration in the solid sample.

[0172] Measurement of hydrolysis resistance Ten-gram pellets of each of the PGAs obtained in the examples were placed in 250 ml of deionized water in a glass bottle with a lid. During aging in an oven at 38 °C, the conductivity of the water was measured every 24 hours, and the amount of time required for the conductivity of the water to increase (due to the release of glycolic acid) was adopted as the hydrolysis resistance.

[0173] Measurement of melt viscosity and related properties According to ASTM D4440-08, at a temperature of 260 °C, 1 to 100 seconds -1 The melt viscosity of the sample was measured using a parallel plate rheometer operating at various shear rates in the range of. The instrument used was a 25 mm diameter parallel plate rheometer available as DHR3 from TA Instruments. The value of tan δ (i.e., the ratio of the loss modulus G” to the storage modulus G’) was also measured. At a constant shear rate of 10 seconds -1 as a function of time, at a temperature of 260 °C, the melt stability value was measured according to the same ASTM D4440-08 by recording the melt viscosity.

[0174] Example 1 (According to the present invention) A 7.5 l stainless steel double-jacketed reactor equipped with a heater, a cooler, temperature and pressure sensors, and a mechanical stirrer was charged with 4500 g of a 70 wt% aqueous glycolic acid solution (GA; 41.420 mol, regarded as 1.0000 mol basis), 10.004 g of trimethylolpropane (TMP; 0.075 mol, 0.0018 mol per 1 mol of GA), 3.584 g of cyclohexanedimethanol (CHDM, 0.025 mol, 0.0006 mol per 1 mol of GA), and 0.536 g of methanesulfonic acid (MSA; 0.006 mol, 0.00014 mol per 1 mol of GA).

[0175] The reactor was then closed and purged three times alternately with vacuum and nitrogen. The reaction solution was rapidly heated to 50 °C under mechanical stirring. The pressure was reduced to 600 mbar and heating was continued from 50 °C to 100 °C over 30 minutes. The distillation of water was started. The temperature was slowly raised to 130 °C over 60 minutes and the distillation of water was gently continued. When most of the water had been removed, the temperature was raised more rapidly to 220 °C over 30 minutes.

[0176] As soon as 220 °C was reached, the pressure was gradually reduced to 30 mbar over 30 minutes. The temperature was then finally raised to 230 °C and kept stable for the rest of the synthesis. The vacuum was applied for more than 270 minutes to increase the GA conversion rate.

[0177] The reaction mixture was then returned to atmospheric pressure using nitrogen. The PGA was taken out of the kettle through the bottom valve and collected on an SS tray on dry ice. The hard solidified PGA mass was taken out and weighed. Crude yield: 2.10 kg (about 88%).

[0178] The polymer was ground into small particles with a diameter of less than 2 mm using a high-speed grinder, classified through a 2 mm sieve, and further dried overnight in a vacuum oven at 90 °C.

[0179] To obtain a homogeneous particle size distribution and consistency, the particles were pelletized with a 19 mm diameter BRABENDER extruder equipped with a 25 L / D single screw having a compression ratio of 3:1. The die was a 1-strand die (2 mm holes) and the strands were "die face cut" in the dry state. To cope with the low viscosity of the melt polymerized prepolymer, the screw speed used was 60 rpm and the temperature profile was kept low (a flat temperature profile of 195 °C, four heating zones in the extruder; one heating zone in the die). The typical output was about 2.1 kg / hour. The resulting pellet size was approximately 2 mm in diameter and approximately 3 mm in length.

[0180] The pellets thus obtained were introduced into a double-wall rotary tumbler apparatus for uniform mixing and for further polymerization in the solid phase by applying heat and drawing a vacuum. The tumbler used had an overall volume of 15 l / an effective volume of 6 l. Approximately 2 kg of polymer was used per batch.

[0181] After closing the tumbler, rotation was started at 8 rpm. The vacuum pump was started to reach a vacuum of 5 - 10 mbar in the tumbler. At the same time, the tumbler was flushed with nitrogen (flow rate set at 50 l / hour). Oil circulating in the double wall was heated to raise the temperature from room temperature to 214 °C over 16 hours.

[0182] The tumbler was equipped with a sampling valve, and at different times of solid-state polymerization (SSP), test specimens of the polymer of reduced weight were carefully taken out and the melt viscosity was analyzed using a parallel plate rheometer. After reaching the desired melt viscosity, heating was stopped, SSP was stopped, and the product was cooled.

[0183] After 66 hours of SSP at 214 °C, -1 1.8 kg of PGA polymer with a melt viscosity of 647 Pa·s at a shear rate of 10 s−1 was obtained.

[0184] The residual MSA in the final PGA after SSP was titrated according to the described method and was found to be 0.005 mol% with respect to GA units.

[0185] Example 2 (according to the present invention) Into the reactor described in Example 1, 4500 g of a 70 wt% aqueous glycolic acid solution (GA; 41.420 mol, regarded as 1.0000 mol basis), 8.892 g of trimethylolpropane (TMP; 0.066 mol, 0.0016 mol per 1 mol of GA), 9.557 g of cyclohexanedimethanol (CHDM, 0.066 mol, 0.0016 mol per 1 mol of GA) and 0.536 g of methanesulfonic acid (MSA; 0.006 mol, 0.00014 mol per 1 mol of GA) were charged.

[0186] The exact same protocol as in Example 1 was applied, and 2.20 kg of PGA was recovered (crude yield 92%).

[0187] The powder was pelletized, and the exact same protocol as in Example 1 was applied to increase the melt viscosity by SSP.

[0188] After 78 hours of SSP at 214 °C, 1.8 kg of PGA polymer with a melt viscosity of 634 Pa·s at a shear rate of 10 s -1 was obtained.

[0189] The residual MSA in the final PGA after SSP was titrated according to the described method and found to be 0.005 mol% with respect to the GA unit.

[0190] Example 1 (C) (Comparative Example) Using the same apparatus and protocol as for Example 1, the loading of 4500 g of 70 wt% aqueous glycolic acid solution (GA; 41.420 mol, regarded as 1.0000 mol basis), 8.892 g of trimethylolpropane (TMP; 0.066 mol, 0.0016 mol per 1 mol of GA), 6.193 g of isophthalic acid (IPA, 0.037 mol, 0.0009 mol per 1 mol of GA) and 0.819 g of methanesulfonic acid (MSA; 0.009 mol, 0.00021 mol per 1 mol of GA) was converted to 2.15 kg of PGA (crude yield 90%).

[0191] The powder was pelletized, and the exact same protocol as in Example 1 was applied to increase the melt viscosity by SSP.

[0192] After 63 hours of SSP at 214 °C, 1.8 kg of PGA polymer with a melt viscosity of 582 Pa·s at a shear rate of 10 s -1 was obtained.

[0193] The residual MSA in the final PGA after SSP was titrated according to the described method and found to be 0.005 mol% with respect to the GA unit.

[0194] Example 2(C) (Comparative Example) Similarly, the loading of 4500 g of 70 wt% glycolic acid aqueous solution (GA; 41.420 mol, regarded as 1.0000 mol basis), 8.892 g of trimethylolpropane (TMP; 0.066 mol, 0.0016 mol per 1 mol of GA) and 0.536 g of methanesulfonic acid (MSA; 0.006 mol, 0.00014 mol per 1 mol of GA) was converted to 2.20 kg of PGA (crude yield 92%).

[0195] The powder was pelletized and the exact same protocol as in Example 1 was applied to increase the melt viscosity by SSP.

[0196] After 48 hours of SSP at 214 °C, 1.8 kg of PGA polymer with a melt viscosity of 738 Pa·s at a shear rate of 10 s -1 was obtained.

[0197] The residual MSA in the final PGA after SSP was titrated according to the described method and found to be 0.005 mol% with respect to the GA unit.

[0198] The tan δ and hydrolysis resistance measured for the PGA obtained in different examples according to the above method are shown in Table 1.

[0199] The melt viscosity over time (melt stability) at 260 °C and 10 s -1 for the PGA obtained in different examples is shown in Table 2.

[0200] [Table 1]

[0201] From the results shown in Table 1, it can be understood that the PGA obtained according to the present invention is characterized by a significant improvement in resistance to hydrolysis compared to the PGA obtained according to the comparative example.

[0202] [Table 2]

[0203] From the results shown in Table 2, it can be understood that the PGA obtained according to the present invention is characterized by a significantly improved melt stability over time as compared to the melt stability over time of the PGA obtained according to the comparative example.

[0204] This results in significant benefits from the perspective of the PGA processing window for typical melt processing techniques. Such more stable PGA is easier to handle and has more predictable rheological behavior during pelletization, compounding, injection molding, blow molding, compression molding, and film extrusion. This also reduces the need for additional moisture protection for the equipment. It also allows the polymer to be melt processed more than once without the melt strength dropping below an acceptable level for typical melt processes.

Claims

1. A glycolic acid polymer [polymer (PGA)], wherein the polymer PGA is (i) glycolic acid (GA); (ii) optionally, at least one hydroxy acid [hydroxy acid (A)] having only one hydroxyl group and only one carboxylic acid group different from GA (wherein the molar amount of hydroxy acid (A) is at most 5 mol% based on the total moles of GA and hydroxy acid (A)); (iii) at least one polyol [polyol (H)] containing at least three hydroxyl groups and no carboxylic acid group; (iv) at least one alcohol [alcohol (AO)] containing one or two hydroxyl groups and no carboxylic acid group; and (v) optionally, at least one carboxylic acid [monoacid (C)] containing one carboxylic acid group and no hydroxyl group A glycolic acid polymer obtained from a polycondensation reaction of a monomer mixture consisting of.

2. - The amount of polyol (H) is such that the number of its hydroxyl groups is included in the range of 0.050 to 1.200% with respect to the total number of carboxyl groups of glycolic acid and, if present, the hydroxy acid (A); - The amount of alcohol (AO) is such that the number of its hydroxyl groups is included in the range of 0.010 to 0.750% with respect to the total number of carboxylic acid groups of glycolic acid and, if present, the hydroxy acid (A); - If present, the amount of monoacid (C) is such that the number of its carboxylic acid groups is included in the range of 0.010 to 2.0% with respect to the total number of hydroxyl groups of glycolic acid and, if present, the hydroxy acid (A), The polymer (PGA) according to Claim 1.

3. The monomer mixture consists of the glycolic acid (GA), the hydroxy acid (A), the polyol (H), the alcohol (AO), and optionally the monoacid (C), the hydroxy acid (A) is selected from the group consisting of lactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, and 6-hydroxycaproic acid, and / or the hydroxy acid (A) is present in an amount of at most 4 mol% based on the total moles of GA and hydroxy acid (A). The polymer (PGA) according to Claim 1 or 2.

4. The polyol (H) is - In particular, triols selected from the group consisting of glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, 2,3 - bis(2'-hydroxyethyl)-cyclohexan-1-ol, hexane-1,2,6-triol, 1,1,1-tris(hydroxymethyl)ethane, 3-(2'-hydroxyethoxy)propane-1,2-diol, 3-(2'-hydroxypropoxy)-propane-1,2-diol, 2-(2'-hydroxyethoxy)-hexane-1,2-diol, 6-(2'-hydroxypropoxy)-hexane-1,2-diol, 1,1,1-tris-[(2'-hydroxyethoxy)-methylethane, 1,1,1-tris-[(2'-hydroxypropoxy)-methyl-propane, 1,1,1-tris-(4'-hydroxyphenyl)ethane, 1,1,1-tris-(hydroxyphenyl)-propane, 1,1,5-tris-(hydroxyphenyl)-3-methylpentane, trimethylolpropane ethoxylate, trimethylolpropane propoxylate, tris(hydroxymethyl)aminomethane; - Tetrols selected from the group consisting of diglycerol, di(trimethylolpropane), pentaerythritol, 1,1,4-tris-(dihydroxyphenyl)-butane; - Polyols containing five hydroxyl groups, in particular triglycerol; - Polyols containing six hydroxyl groups, in particular dipentaerythritol, mannitol, sorbitol; and - Polyols containing eight hydroxyl groups, in particular tripentaerythritol selected from the group consisting of; and / or the polyol (H) is used in an amount such that the number of its hydroxyl groups is at least 0.050% relative to the total number of carboxylic acid groups of glycolic acid and, when present, the hydroxy acid (A), the polymer (PGA) according to any one of claims 1 to 3.

5. The alcohol (AO) is a diol (D) characterized by a boiling point at atmospheric pressure of at least 100 °C, and / or a diol (D) used in an amount such that the number of its hydroxyl groups is at least 0.010% relative to the total number of carboxylic acid groups of glycolic acid and, when present, the hydroxy acid (A), the polymer (PGA) according to any one of claims 1 to 4.

6. The polymer (PGA) according to any one of claims 1 to 5, wherein the alcohol (AO) is a diol (D) selected from diethylene glycol, 1,4-cyclohexanedimethanol, isosorbide, dodecane 1,12-diol, and mixtures thereof.

7. The monoacid (C) is of the formula: R Ｈｍ -COOH (Formula C-1) (wherein R Ｈｍ is a monovalent aliphatic group having one or more carbon atoms, particularly having three or more carbon atoms), an aliphatic monoacid, or an aromatic monoacid selected from the group consisting of benzoic acid, naphthoic acid, and phenylacetic acid. The polymer (PGA) according to any one of claims 1 to 6.

8. A method for producing a polymer (PGA) according to any one of claims 1 to 7, the method comprising polycondensing glycolic acid (GA), optionally at least one hydroxy acid (A), at least one polyol (H), at least one alcohol (AO), and optionally at least one monoacid (C) as defined in claims 1 to 7.

9. The method according to claim 8, wherein the method comprises a first step of polymerizing in a molten state to form a prepolymer and a second step of solid-state polymerization (SSP) to increase the molecular weight of the prepolymer.

10. A composition (C) comprising a polymer (PGA) according to any one of claims 1 to 7 and at least one additional raw material, the raw materials being, inter alia, antioxidants, heat stabilizers, buffers, UV and light stabilizers, pigments, lubricants, processing aids, hydrolysis stabilizers, reinforcing agents, toughening agents, plasticizers, colorants, antistatic agents, flame retardants, nucleating agents, and other processing aids.

11. The composition according to claim 10, wherein the composition comprises a polymer (PGA) according to any one of claims 1 to 7 and a reinforcing agent in an amount of 10 to 60% by weight based on the total weight of the composition (C).

12. A method for producing a multi-layered, optionally stretched, optionally thermoformed product, the method comprising: (i) forming a multi-layer resin laminate comprising at least one layer of a polymer (PGA) according to any one of claims 1 to 7 or at least one layer of a composition (C) according to either claim 10 or 11 and at least one layer of a thermoplastic different from the polymer (PGA) by processing from a melt; (ii) optionally stretching the multi-layer resin laminate; (iii) optionally thermoforming the optionally stretched laminate to produce the multi-layered, optionally stretched, optionally thermoformed product A method comprising.

13. An article comprising the polymer (PGA) according to any one of claims 1 to 7, or the composition (C) according to claim 10 or 11.

14. The article according to claim 13, which is a bottle, an article for hydrocarbon resource recovery, a packaging film, a sanitary product, a disposable pod, a structural component for electronic applications, or a biomedical article.

15. The article according to claim 13 or 14, which is a bottle, an article for hydrocarbon resource recovery, or a sanitary product.

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