MX2008007156A - Poly(trimethylene terephthalate)/poly(alpha-hydroxy acid) films - Google Patents

Abstract

This invention relates to poly(trimethylene terephthalate)/poly(alpha-hydroxy acid) films, methods for making the same and end uses thereof.

Description

FILMS OF POLY (TRIMETHYLENE TERHETHYLATE) / POLY (HYDROXYLATED ALPHA) FIELD OF THE INVENTION This invention relates to poly (trimethylene terephthalate) / poly (hydroxy acid alpha) films, methods for making them and their terminal uses.

BACKGROUND OF THE INVENTION Poly (trimethylene terephthalate) ("PTT") and its use in many applications, including molded, formed products, has been described in the literature. PTT is a polyester derived from terephthalic acid or an ester thereof and trimethylene glycol (also known as 1,3-propanediol) ("PDO"). The PDO can be prepared by different chemical or biochemical routes, which include different sources of sugar, such as corn, and in this way, can be prepared from a renewable resource. New PTT articles having improved hardness, elongation and surface properties have been desired. In addition, since the terephthalic acid and its esters are currently prepared from petroleum base, it is desired to increase the life (renewable resource base) of the PTT compositions without damaging the general properties of the products. REF .: 193076 Japanese patent application No. 2003-041435 discloses mixtures of PTT and 1-10% by weight of a polyester consisting essentially of polylactic acid. The mixtures are used to prepare cut, hollow, corrugated fibers. Poly (lactic acid) can also be prepared from a renewable resource, which is prepared from lactic acid (2-hydroxypropionic acid) and its intermolecular esters, which, in turn, are prepared from carbohydrates by fermentation of lactic acid. Japanese Patent Publication No. 2003-041435 focuses on the use of polylactic acid to provide a more stable corrugation and does not disclose molded, formed or improved products thereto.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to a film comprising a polymer composition comprising from about 20 to about 98% by weight of the polymer composition of poly (trimethylene terephthalate) and from about 80 to about 2% by weight, in weight of the poly (hydroxy acid alpha) polymer composition. Preferably, the polymer composition comprises at least about 30% by weight, more preferably at least 40% by weight, even more preferably at least 50% by weight, even more preferably more than 50% by weight, even more preferably at least 60% by weight and more preferably at least 75% by weight, by weight of the polymer composition of poly (trimethylene terephthalate). Preferably the polymer composition comprises up to about 95% by weight of poly (trimethylene terephthalate). Preferably, the polymer composition comprises up to about 70% by weight, more preferably up to about 60% by weight, more preferably up to about 50% by weight, more preferably less than about 60% by weight, more preferably up to about 50% by weight , more preferably less than about 50% by weight, more preferably up to about 40% by weight and more preferably up to about 25% by weight, by weight of the polymer composition of the poly (hydroxy acid). Preferably the composition comprises at least about 5% by weight, by weight of the polymeric composition of the poly (hydroxy acid) alpha. Preferably, the poly (trimethylene terephthalate) is made with a 1,3-propanediol prepared by a fermentation process using a renewable biological source. Preferably, the poly (hydroxy acid) alpha is the polylactic acid, more preferably a polylactic acid derived biologically. Preferably, the film is from about 0.1 thousandths to about 100 thousandths of a thickness. In a preferred embodiment, the film is from about 0.1 thousandths to about 15 mils thick. In another preferred embodiment, the film is about 15 mils to about 100 mils thick. In a preferred embodiment, the film is a biaxially oriented film. In another preferred embodiment, the film is a molded film. In a preferred embodiment, the film is a monolayer film. In another embodiment, the invention relates to a multilayer film, comprising at least one film layer comprising a polymer composition comprising about 20 to about 98% by weight of the polymer composition, poly (trimethylene terephthalate) and about 80 to about 2% by weight, by weight of the polymer composition, of poly (hydroxy acid alpha). In a preferred embodiment, the multilayer film is prepared by laminating at least one film layer to at least one other film layer or substrate. In another preferred embodiment, a multilayer film is prepared by coextruding at least one film layer with at least one other film layer selected from the group consisting of polyolefin, ethylene copolymer, ionomer, polyamide, polycarbonate, acrylic, polystyrene, ethylene vinyl alcohol, polyvinylidene chloride and other layers of synthetic polymer films; and wherein the multilayer film optionally comprises one or more adhesive fastening layers. In a preferred embodiment, the film is a blown film. The invention also relates to elaborate articles of the film. Such articles may be prepared from monolayer or multilayer films. Examples of the articles are containers (e.g. bottles and cosmetic containers) and other multilayer laminated structures. Thermoformed and vacuum thermoformed articles are included. The invention also relates to the preparation of films, including monolayer films and multilayer films and articles. For example, in one embodiment it relates to a process for preparing a film, comprising the steps of: (a) providing a polymer composition comprising from about 20 to about 98% by weight, by weight of the polymer composition of poly (terephthalate) of trimethylene) and about 80 to about 2% by weight, by weight of the poly (hydroxy acid alpha) polymer composition; and (b) formation of a movie. The films, film layers and articles of the invention had similar or better properties to those prepared only with PTT. Most notably, the module and surface appearance have improved. This is unexpected given that poly (hydroxy acid alpha) polymers have slightly lower physical and mechanical properties than PTT. In this way, by using poly (hydroxy acid alpha) polymers, the skilled person can increase the life content (percentage of renewable resources) in a film, film layer or article without significantly deteriorating the properties of the final product.

DETAILED DESCRIPTION OF THE INVENTION All All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which the invention pertains. In case of conflict, this specification, including definitions, will take over. Except when expressly specified, trademarks are shown in upper case. The materials, methods and examples herein are illustrative only and, except where specifically stated, are not intended to be limiting. Although methods and materials similar or equivalent to those described herein can be used in practice or tested in the present invention, suitable methods and materials are described herein. Unless stated otherwise, all percentages, parts, relationships, etc., are by weight. When a quantity, concentration or other value or parameter is given as a range, preferred range or a list of higher preferred values and lower preferred values, this shall be understood to specifically describe all ranges formed of any upper range or value limit pair. preferred and any lower interval limit or preferred value, without taking into account whether the intervals are described separately. When a range of numerical values is mentioned herein, unless stated otherwise, the range is intended to include the terminal points thereof, and all integers and fractions within the range. The scope of the invention is not intended to be limited to the specific values mentioned when defining a range. When the term "approximately" is used to describe a value or an end point of an interval, the description should be understood to include the specific value and the referred end point. As used herein, the terms "comprising", "comprising", "including", "including", "having", "having" or any other variations thereof, are intended to cover an inclusion not Exclusive For example, a process, method, article or apparatus comprising a list of elements is not necessarily limited only to the elements but may include other elements not expressly listed or inherent in such process, method, article or apparatus. In addition, unless expressly stated otherwise, "or" refers to inclusive and is not exclusive. For example, a condition A or B is satisfied by any of the following: A is true (or present) and B is false (or is not present), A is false (or is not present) and B is true (or present ) and A and B are true (or present). The use of "a" or "an" is used to describe elements and components of the invention. This is done exclusively for convenience and to give a general sense of the invention. This description should not be read to include one or at least one, and the singular includes the plural, unless it is obvious that it means otherwise. This invention relates to polymer compositions, fused combination blends, films, film layers and articles (or layers of articles) comprising the polymer compositions. The polymeric compositions and the combined molten mixtures comprise poly (trimethylene terephthalates) and polymers of alpha hydroxy acids. The amount of the hydroxy acid polymer or alpha hydroxy acids is at least 2%, more preferably at least about 5% and in some cases more preferably at least about 10%. The amount of the polymer of an alpha hydroxy acid is up to about 80%, preferably up to about 75%, in another embodiment up to about 60%, in yet another mode up to 50%, in an additional mode less than 50%, in yet another mode up to about 40% and in an additional mode up to about 25%. Preferably, the polytrimethylene terephthalate is used in an amount of up to about 98%, in another embodiment preferably up to about 95% and in an additional mode preferably up to about 90%. Preferably, it is used in an amount of at least about 20%, in another embodiment of at least about 25%, in another embodiment of at least about 40%, in yet another preferred mode of at least about 50. %, in an additional mode greater than 50%, in an additional mode of at least about 60%, in an additional mode of at least about 75%. The above are percentages by weight, and are based on the total weight of the polymer compositions and the combined molten polyester blends, respectively. For convenience, the polymeric compositions of the invention are often referred to as "PTT / PAHA polymers". Polytrimethylene terephthalate or PTT is understood to encompass homopolymers and copolymers containing at least 70 mol% of repeating units of trimethylene terephthalate. Preferred poly (trimethylene terephthalates) contain at least 85% mol, more preferably at least 90% mol, even more preferably at least 95 or at least 98% mol and more preferably approximately 100% mol of repeated units of trimethylene terephthalate. Poly (trimethylene terephthalate) is generally produced by the acid catalyzed polycondensation of 1,3-propanediol and terephthalic acid / diester, with optional minor amounts of other monomers. When the PTT is a copolymer, it may contain up to 30 mol%, preferably up to 15 mol%, more preferably up to 10 mol%, even more preferably up to 5 mol% and more preferably up to 2 mol%, and repeated units that contain other units. This repeated unit preferably contains dicarboxylic acids having 4-12 carbon atoms (for example, butanedioic acid, pentanedioic acid, dodecandioic acid and 1,4-cyclohexanedicarboxylic acid), aromatic dicarboxylic acids, in addition to terephthalic acid and they have 8-12 carbon atoms (eg, isophthalic acid and 2,6-naphthalenedicarboxylic acid) and linear, cyclic and branched aliphatic diols having 2-8 carbon atoms in addition to 1,3-propanediol (eg, ethanediol, 1,2-propanediol, 1,4-butanediol, 3-methyl-1, 5-pentanediol, 2,2-dimethyl-1,3-propandiol, 2-methyl-1,3-propanediol and 1,4-cyclohexanediol) . The poly (trimethylene terephthalate) may contain minor amounts of other comonomers, and such comonomers are usually selected so that they do not have a significant adverse effect on the properties. These other comonomers include 5-sodium sulfoisophthalate, for example, at a level in the range of about 0.2 to 5 mol%. Very small amounts of tri-functional comonomers, for example, trimellitic acid, can be incorporated for viscosity control. A particular poly (trimethylene terephthalate) is one in which the 1,3-propanediol used to make the polymer comprises (preferably substantially comprises) a 1,3-propanediol prepared by a fermentation process using a renewable biological source. As an illustrative example of a starting material from a renewable source, the biochemical pathways to 1, 3-propanediol (PDO) using raw materials produced from biological and renewable resources, such as corn raw material, have been described. For example, bacterial strains capable of converting glycerol to 1,3-propanediol are found in the species Kl ebsiella, Ci trobacter, Clos tridi um and Lactobaci ll us. The technique is described in several publications, including US5633362, US5686276 and US5821092. US5821092 describes, inter alia, a process for the biological production of 1,3-propanediol from glycerol using recombinant organisms. The process incorporates E. coli bacteria, transformed with a heterologous ddu dehydratase diol gene, which has specificity for 1,2-propanediol. Transformed E. coli develops in the presence of glycerol as a carbon source and 1,3-propanediol is isolated from the growth medium. Since bacteria and yeasts can convert glucose (eg, corn sugar) or other carbohydrates to glycerol, the processes described in these publications provide a quick, cheap and environmentally responsible source of the 1,3-propanediol monomer. Biologically derived 1,3-propanediol, such as that produced by the processes described and referenced above, contains carbon from the atmospheric carbon dioxide incorporated by the plants, which make up the raw material for the production of 1,3-propanediol . Thus, the 1, 3 -propanediol biologically derived for use in the context of the present invention contains only renewable carbon, and not carbon based on fossil fuel or petroleum based. Therefore, the poly (trimethylene terephthalates) based thereon using the biologically derived 1,3-propanediol have less impact on the environment than the 1,3-propanediol used in the compositions that do not deplete the fossil fuels diminished and , once they degrade, it releases carbon black into the atmosphere for use by the plants again. Preferably, the 1,3-propanediol used as the reagent or as a component of the reagent will have a purity greater than about 99%, and more preferably greater than about 99.9% by weight, determined by gas chromatographic analysis. Particularly preferred are the purified 1,3-propanediols as described in US7038092, US2004-0260125A1, US2004-0225161A1 and US2005-0069997A1. The purified 1,3-propanediol preferably has the following characteristics: (1) an ultraviolet absorption at 220 nm less than about 0.200 and at 250 nm less than about 0.075 and at 275 nm less than about 0.075; and / or (2) a composition having a color value L * a * b * "b *" less than about 0.15 (ASTM D6290) and an absorbance at 270 nm less than about 0.075; and / or (3) a peroxide composition of less than about 10 ppm; and / or (4) a concentration of total organic impurities (organic compounds in addition to 1,3-propanediol) less than about 400 ppm, more preferably less than about 300 ppm, and even more preferably less than about 150 ppm, as measured by chromatography Of gas. The intrinsic viscosity of the poly (trimethylene terephthalate) of the invention is at least about 0.5 dL / g, preferably at least about 0.7 dL / g, more preferably at least about 0.8 dL / g, more preferably of at least about 0.9 dL / g and more preferably of at least about 1 dL / g. The intrinsic viscosity of the polyester composition of the invention is preferably up to about 2.5 dL / g, more preferably up to about 2 dL / g, even more preferably up to about 1.5 dL / g and more preferably up to about 1.2 dL / g. Poly (trimethylene terephthalate) and preferred manufacturing techniques for the manufacture of poly (trimethylene terephthalate) are described in US5015789, US5276201, US5284979, US5334778, US5364984, US5364987, US5391263, US5434239, US5510454, US5504122, US5532333, US5532404, US5540868, US5633018, US5633362, US5677415, US5686276, US5710315, US5714262, US5730913, US5763104, US5774074, US5786443, US5811496, US5821092, US5830982, US5840957, US5856423, US5962745, US5990265, US6232511, US6235948, US6245844, US6255442, US6277289, US6281325, US6297408, US6312805, US6325945, US6331264, US6335421, US6350895, US6353062, US6437193, US6538076, US6841505 and US6887953, all of which are incorporated herein by reference. The poly (trimethylene terephthalates) useful as the polyester of this invention are those commercially available from E.I. du Pont de Nemours and Company, Wilmington, Delaware, under the trademark SORONA and Shell Chemicals, Houston, Texas under the trademark CORTERRA. The polymerized alpha hydroxy acids ("PAHA") used in the practice of the present invention include the lactic acid polymers (including polymers of their stereospecific dimeric L (-) lactide), glycolic acid (including their dimeric glycolide) and the acid 2- hydroxybutyric. Also included in the term "polymerized alpha hydroxy acid" are the copolymers of PLA, such as the copolymers of PLA and e-caprolactone (2-oxepanone) and / or α-caprolactone (5-ethyl-2-oxolanone). Any degree of PLA can be used for the practice of the present invention. The preferred poly (lactic acid) acid (PLA) used in the practice of the present invention is a 100% biological derivative polymer, catalytically prepared from L (-) - lactide, preferably having a melting point of 130-200 ° C. The intrinsic viscosity of the PLA used in the practice of the present invention is preferably at least about 0.7 dL / g, more preferably at least about 0.9 dL / g and is preferably up to about 2.0 dL / g, more preferably to approximately 1.6 dL / g. The PLAs suitable for the practice of this invention are available from Cargill, Inc., Minetonka, MN and a preferred grade is PLA Polymer 4040D and others. PTT / PAHA polymer compositions can be prepared by any known technique, including physical blends and melt blends. Preferably, the PTT and PAHA are melted and compound mixtures. Preferably the PTT and PAHA are mixed and heated to a temperature sufficient to form a mixture, and once cooled, the mixture is formed into a formed article, such as pellets. The PTT and PAHA can be formed in a mixture in many different ways. For example, they can (a) be heated and mixed simultaneously, (b) pre-mixed in a separate apparatus before heating or (c) heated and then mixed. As an example, the polymer blend can be made by injection of the transfer line. Mixing, heating and forming can be carried out by conventional equipment designed for such purpose, such as extruders, Bunbury mixers or the like. The temperature should be above the melting points of each component, but below the lowest decomposition temperature and, therefore, should be adjusted for any particular composition of the PAT / PAHA polymers. The temperature is typically in the range of about 180 ° C to about 260 ° C, preferably at least about 230 ° C and more preferably up to about 250 ° C, depending on the particular PTT and PAHA of the invention. The polymer compositions, if desired, may contain some additives, for example, thermal stabilizers, nucleating agents, viscosity improvers, optical brighteners, pigments and antioxidants. Depending on the application of the intended end use, the polymer may contain minor amounts of other known thermoplastic resins or additives that are conventionally added to thermoplastic resins, eg, stabilizers, such as ultraviolet absorbers, antistatic agents. Of course, these additives should not be used in amounts that would adversely affect the benefits achieved by the present invention. Polyamides, such as Nylon 6 or Nylon 6-6 can be added in amounts of less than about 0.5 to about 15% by weight, based on the weight of the polymer composition, to improve the properties (e.g., strength) and capacity of processing the compositions of the invention.

A preferred nucleating agent, preferably 0.005 to 2% by weight of an onosodium salt of a dicarboxylic acid selected from the group consisting of monosodium terephthalate, monosodium naphthalenedicarboxylate and monosodium isophthalate as a nucleating agent, can be added as described in US6245844. The compositions of the invention can be formed into biaxially molded or oriented films, sheets or other articles. These films usually have a size of approximately 0.1 thousandths to approximately 100 thousandths. The film may be a monolayer film, or a multilayer film formed in a co-extrusion with other layers of film including polyolefins, ethylene copolymers, ionomers, polyamides, polycarbonates, acrylics, polystyrenes, adhesive clamping layers, ethylene vinyl alcohol, chloride of polyvinylidene or other synthetic polymers. The monolayer film can also be laminated to other films or substrates. The polymeric compositions can be made on a film, which includes films molded and oriented biaxially, using conventional equipment. The stages involved are typically: the preparation of a dry polymer mixture, melt mixing of the polymers, extrusion of the polymers to form pellets (including other shapes, such as flakes, etc.), remelting of the pellets, extruding the pellets through a die and can be carried out at temperatures in the range of about 180 ° C to about 260 ° C. The polymer compositions of the invention provide new changes in physical properties over the PTT itself. The following examples are presented for the purpose of illustration of the invention and are not intended to be limiting. All parts, percentages, etc., are by weight unless otherwise indicated.

EXAMPLES Materials The PTT used was bright poly (trimethylene terephthalate) SORONA (E.I. du Pont de Nemours and Company, Wilton, DE), which has an intrinsic viscosity of 1.02 dl / g. The PLA used was poly (lactic acid) PLA Polymer 4040D from Cargill, Inc., Minetonka, MN.

Test method 1. Intrinsic viscosity measurement The intrinsic viscosities (IV) of PTT and PAHA were determined using the viscosity measured with a Viscotek Forced Flow Viscometer Y900 (Viscotek Corporation, Houston, TX) for the polymer dissolved in trifluoroacetic acid / methylene chloride 50/50% by weight at a concentration of 0.4 grams / dL at 19 ° C following an automated method based on ASTM D 5225-92. The IV values measured from PTT were correlated with the IV values manually measured in phenol / 1,1,2,2-tetrachloroethane 60/40% by weight following ASTM D 4603-96. See also US5840957.

Test method 2. Measurements of physical properties The physical properties of the films were measured using the test samples using a voltage tester from Instron Corp., model No. 1125 (Instron Corp., Norwood, MA). The stress properties were measured in accordance with ASTM D-638.

Examples 1-3 and Comparative Example A Films were prepared by extrusion of the polymers according to the invention and a PTT control polymer.

The PTT was dried in an air oven at 120 ° C for 16 hours. The polymer PLA 4040D was dried at 80 ° C for 16 hours. The polymer blends of the PTT and PLA were prepared in a 28 mm twin screw extruder at 249 ° C. The films were extruded through a standard die, quenched by passing through a roller cooled with water, cooled to room temperature and rolled up. Films of different thicknesses were prepared and the data for the 4 mil thick films are given below in Table 1. Each data is the average of 10 individual test samples.

Table 1 - Properties of the PTT / PLA film XD = transverse direction. MD = machine direction (longitudinal). The module of the samples (in the transverse direction and the direction of the machine) increased with the increase in PLA levels. The effort in the transverse direction was also improved with the addition of PLA to PTT. These changes were particularly unexpected given that PLA generally has significantly worse resistance properties, such as the modulus, than PTT. The above description of the embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms described. Many variations and modifications of the embodiments described herein will be obvious to one of ordinary skill in the art from the point of view of the description. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (7)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. Film, characterized in that it comprises a polymeric composition comprising from about 20 to about 98% by weight, by weight of the poly (terephthalate) polymer composition of trimethylene) and about 80 to about 2% by weight, by weight of the poly (hydroxy acid alpha) polymer composition.
2. 2. The film according to claim 1, characterized in that the poly (hydroxy acid) is polylactic acid.
3. 3. The film according to claim 2, characterized in that the polylactic acid is a biological derivative polymer.
4. 4. The film according to claim 1, characterized in that the poly (trimethylene terephthalate) is made with a 1,3-propanediol prepared by a fermentation process using a renewable biological source.
5. 5. The film according to claim 3, characterized in that the poly (trimethylene terephthalate) is made with a 1,3-propanediol prepared by a fermentation process using a renewable biological source.
6. 6. The film according to claim 1, characterized in that it is from about 0.1 thousandths to about 100 mils thick.
7. 7. Multilayer film, characterized in that it comprises at least one layer of film comprising a film according to any of claims 1-6.