DE102015217309A1 - polymer composition - Google Patents

Abstract

The present invention relates to a polymer composition comprising: i) from 70 to 95% by weight, based on the total weight of components i to ii, of a polyhydroxyalkanoate; and ii) from 5 to 30% by weight, based on the total weight of components i to ii, of a terephthalic acid di-C4-C13-alkyl ester. Furthermore, the invention relates to biodegradable polyester films or biodegradable injection-molded or thermoformed articles containing the above-mentioned. Polymer composition.

Description

• i) 70 bis 95 Gew.-%, bezogen auf das Gesamtgewicht der Komponenten i bis ii, eines Polyhydroxyalkanoats; und
• ii) 5 bis 30 Gew.-%, bezogen auf das Gesamtgewicht der Komponenten i bis ii, eines Terephthalsäure-di-C₄-C₁₃-alkylesters.

The present invention relates to a polymer composition comprising:

• i) from 70 to 95% by weight, based on the total weight of components i to ii, of a polyhydroxyalkanoate; and
• ii) 5 to 30 wt .-%, based on the total weight of components i to ii, of a terephthalic acid di-C ₄ -C ₁₃ alkyl ester.

Furthermore, the invention relates to biodegradable polyester films or biodegradable injection-molded or thermoformed articles containing the above-mentioned. Polymer composition.

Polyhydroxyalkanoates (PHA), e.g. Polyhydroxybutyrate (PHB) can be synthesized with the help of bacteria. For example, such biotechnological methods are described in Biopolymer, Wiley-VCH, 2002. Polyhydroxyalkanoates thus represent one of the most interesting classes of biopolymers. In addition to their mechanical properties, which can be varied widely by structural diversity, their ecologically safe production and their environmentally friendly disposal - in particular by their ability to biodegrade under anaerobic conditions Polyhydroxyalkanoates in the focus of interest.

Among polyhydroxyalkanoates are usually homopolymers such as poly-3-hydroxybutyrate (3-PHB), poly-4-hydroxybutyrate (4-PHB) or copolymers such as, poly-3-hydroxybutyrate-co-3-hydroxyvalerate, poly-3 hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate, poly-3-hydroxybutyrate-co-3-hydroxyhexanoate and poly-3-hydroxybutyrate-co-4-hydroxybutyrate.

In practice, the property profile of the known polyhydroxyalkanoates, in particular that of the aforementioned homopolymers, can not always be convincing. The polyhydroxyalkanoates sometimes have a sticky, high viscosity behavior. During processing, a high energy input is necessary. A molecular weight reduction of z. Part of temperature-sensitive biopolymers is the direct result. Furthermore, in the film production, the gluing of the roller leads to production losses. In particular, thin films, which are common in the packaging industry, can not be produced economically in this way. Furthermore, especially the homopolymers such as 3-PHB are brittle and less ductile, so that the articles produced therefrom can be improved in terms of their application properties.

In the WO 99/23146 Polyhydroxyalkanoates are described to which plasticizers such as tributyl citrate and Tributylcitratacetat be added. This makes it possible to improve the extensibility of articles made therefrom, with respect to modulus of elasticity and tensile strength, the articles thus produced still leave something to be desired.

The present invention is therefore based on the object to provide biodegradable polymer compositions which do not have the abovementioned disadvantages.

This object is fulfilled by the biodegradable polymer compositions defined in the introduction, which are described in more detail below. The polymer compositions according to the invention differ from those of the prior art by the addition of terephthalic acid di-C ₄ -C ₁₃ -alkyl esters (component ii). The addition of terephthalic acid di-C ₄ -C ₁₃ -alkyl esters, in particular, the tear strength and the modulus of elasticity of the polymer compositions can be improved.

The polymer compositions are described in more detail below:
Polyhydroxyalkanoates (component i) are understood in addition to the systems described at the outset to be primarily poly-4-hydroxybutyrates and poly-3-hydroxybutyrates and copolyesters of the abovementioned polyhydroxybutyrates with 3-hydroxyvalerate, 3-hydroxyhexanoate and / or 3-hydroxyoctanoate. Poly-3-hydroxybutyrate are sold for example by the company. PHB Industrial under the brand name Biocycle ^® and by the company. Tianan under the name Enmat ^®. Poly-3-hydroxybutyrate-co-4-hydroxybutyrates are known in particular from Metabolix. They are marketed under the trade name Mirel ^®. Poly-3-hydroxybutyrate-co-3-hydroxyhexanoates are known from the company P & G or Kaneka. Poly-3-hydroxybutyrate-co-3-hydroxyhexanoates generally have a 3-hydroxyhexanoate content of from 1 to 20 and preferably from 3 to 15 mol%, based on component ii. Particularly preferred is a 3-hydroxyhexanoate content of 10 to 13 mol%. Poly-3-hydroxybutyrate-co-3-hydroxyhexanoates are particularly preferred for the polyester films of this invention. In combination with the components i, and optionally iii, iv and vi, they provide very tear-resistant, transparent films.

The polyhydroxyalkanoates generally have a molecular weight Mw of from 100,000 to 1,000,000, and preferably from 300,000 to 600,000.

Component i is usually used in 70 to 95% by weight, preferably 75 to 90% by weight, based on the total weight of components i to ii. Accordingly, component ii is used in 5 to 30% by weight, preferably 10 to 25% by weight, based on the total weight of components i to ii.

According to the invention, terephthalic acid C ₄ to C ₁₃ dialkyl esters are used as plasticizers in the compositions according to the invention.

The terephthalic acid C ₄ - to C ₁₃ -dialkyl esters according to the invention have, independently of one another, in each case 4 to 13 C atoms, in particular 4 to 10 C atoms, in the alkyl chains, where the alkyl radicals may each be linear or branched.

Preferred terephthalic acid C ₄ - to C ₁₃ dialkyl esters are dialkyldi- (n-butyl) terephthalates, dialkyl di (2-ethylhexyl) terephthalates, dialkyl di- (isononyl) terephthalates or dialkyldi- (2-propylheptyl) terephthalates.

Particularly preferably, in the terephthalic acid-C ₄ - to C ₁₃ dialkyl esters of a di- (n-butyl) -terephthalsäuredialkylester, for example the product available on the market ^"® Eastman effusion Plasticizer" from Eastman Chemical Company, Kingsport, USA.

Particularly preferably, in the terephthalic acid-C ₄ - to C ₁₃ dialkyl esters continue to terephthalic acid-bis (2-ethylhexyl) dialkyl esters, also known under the name Dioktylterephthalat or DOTP, for example that available on the market the product "Eastman 168 ^® "The Eastman Chemical Company, Kingsport, USA, or the also available on the market product" Palatinol ^® DOTP "BASF Corp., Florham Park, USA.

The terephthalic acid C ₄ - to C ₁₃ -dialkyl esters according to the invention are distinguished by a very good compatibility with a large number of different other plasticizers and can also be used in combination with these to achieve certain properties. For special or complex application-related requirements, such as high cold elasticity, high extraction or migration resistance, or very low plasticizer volatility, it may be advantageous to use plasticizer mixtures for softening.

For this reason, the invention also relates to plasticizer mixtures containing at least one inventive terephthalic acid C ₄ - to C ₁₃ dialkyl ester and at least one of the inventive terephthalic acid-C ₄ - to C ₁₃ -dialkylestern different plasticizer.

The additional plasticizer other than the terephthalic acid C ₄ to C ₁₃ dialkyl esters according to the invention is preferably selected from dialkyl cyclohexane-1,2-dicarboxylates, dialkyl phthalates, trialkylaluminium alkyl esters, dialkyl trimellitates, dialkyl adipates, benzoic acid dibenzoates, hydroxybenzoic acid esters, esters of saturated mono- and dicarboxylic acids, esters of unsaturated dicarboxylic acids, amides and esters of aromatic sulfonic acids, alkylsulfonic acid esters, glycerol esters, isosorbide esters, phosphoric acid esters, citric acid triesters, alkylpyrrolidone derivatives, 2,5-furandicarboxylic acid esters, 2,5-tetrahydrofurandicarboxylic acid esters, epoxidized vegetable oils based on triglycerides and saturated or unsaturated fatty acids , Polyesters of aliphatic and aromatic polycarboxylic acids with polyhydric alcohols.

Preferred cyclohexane-1,2-dicarboxylic acid dialkyl esters are cyclohexane-1,2-dicarboxylic acid C ₈ - to C ₁₀ -dialkyl esters, for example cyclohexane-1,2-dicarboxylic acid di- (2-ethylhexyl) ester, cyclohexane-1,2- dicarboxylic acid diisooctyl ester, cyclohexane-1,2-dicarboxylic acid diisononyl ester, cyclohexane-1,2-dicarboxylic acid di (2-propylheptyl) ester or cyclohexane-1,2-dicarboxylic acid diisodecyl ester. Is particularly preferred in the novel compositions diisononyl cyclohexane-1,2-dicarboxylic acid esters as a plasticizer used for example that available on the market product Hexamoll ^® DINCH ^® (CAS No. Europe and Asia.. 166412-78-8; CAS No. USA : 474919-59-0) from BASF SE or also available on the market product Elatur ^® CH (CAS No. Europe and Asia.. 166412-78-8; CAS No. USA: 474919-59-0) of Evonik OXENO.

Preferred dialkyl phthalates independently of one another have 4 to 13 C atoms, preferably 8 to 13 C atoms, in the alkyl chains. A preferred phthalic alkylalkyl is, for example Benzyl butyl phthalate. The trimellitic acid trialkyl esters preferably each independently have 4 to 13 C atoms, in particular 7 to 11 C atoms, in the alkyl chains. The esters of saturated mono- and dicarboxylic acids are preferably esters of acetic acid, butyric acid, valeric acid, succinic acid, adipic acid, sebacic acid, lactic acid or tartaric acid. The adipic acid dialkyl esters preferably each independently have 4 to 13 C atoms, in particular 6 to 10 C atoms, in the alkyl chains. The esters of unsaturated dicarboxylic acids are preferably esters of maleic acid and fumaric acid. The benzoic acid alkyl esters preferably each independently have 7 to 13 C atoms, in particular 9 to 13 C atoms, in the alkyl chains. Examples of preferred benzoic acid alkyl esters are isononyl benzoate, isodecyl benzoate or 2-propylheptyl benzoate. Preferred dibenzoic acid esters of glycols are diethylene glycol dibenzoate and dibutylene glycol dibenzoate. Preferred alkylsulfonic acid esters preferably have an alkyl radical having 8 to 22 C atoms. These include, for example, the phenyl or cresyl esters of pentadecylsulfonic acid. Preferred isosorbide esters are isosorbide diesters, which are preferably each independently esterified with C5 to C13 carboxylic acids. Preferred phosphoric esters are tri-2-ethylhexyl phosphate, trioctyl phosphate, triphenyl phosphate, isodecyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate and bis (2-ethylhexyl) phenyl phosphate. In the citric acid triesters, the OH group can be present in free or carboxylated form, preferably acetylated. The alkyl radicals of the citric acid triesters preferably have, independently of one another, 4 to 8 C atoms, in particular 6 to 8 C atoms. Preference is given to alkylpyrrolidone derivatives having alkyl radicals of 4 to 18 carbon atoms. Preferred 2,5-furandicarboxylic acid dialkyl esters each independently have 4 to 13 C atoms, preferably 8 to 13 C atoms, in the alkyl chains. The epoxidized vegetable oils are, for example, preferably epoxidized fatty acids from epoxidertem soybean oil, available under the tradename Reflex ^® from PolyOne, United States the trade names Proviplast ^® PLS Green 5 and Proviplast ^® PLS Green 8 Fa. Proviron, Belgium, and the trade name Drapex Alpha ^® from. Galata, United States. The polyesters of aliphatic and aromatic polycarboxylic acids are preferably polyesters of adipic acid with polyhydric alcohols, in particular dialkylene glycol polyadipates having 2 to 6 carbon atoms in the alkylene radical.

Furthermore, the polymer composition according to the invention may contain further additives known to the person skilled in the art. For example, the usual additives in plastics technology such as stabilizers; nucleating agents; Lubricants and release agents such as stearates (especially calcium stearate); Waxes such as erucic acid amide, stearic acid amide or behenamide, beeswax or beeswax esters; Antistatic, UV absorber; UV-stabilizer; Antifog agents or dyes. The additives are used in concentrations of 0 to 5 wt .-%, in particular 0.1 to 2 wt .-% based on the polymer composition according to the invention.

Particularly suitable nucleating agents are chalk or talc, which are generally used in 0.1 to 2% by weight, based on the polymer composition of the invention.

Furthermore, the polymer composition may still contain fillers. In this case too, chalk and talc are particularly suitable, although they are used in relatively large amounts of 2 to 50% by weight and preferably 10 to 40% by weight, based on the polymer composition of the invention. Further suitable fillers are: graphite, gypsum, conductive carbon black, iron oxide, calcium chloride, kaolin, silica (quartz), sodium carbonate, titanium dioxide, silicate, wollastonite, mica, montmorellonite and mineral fibers. The minerals can also be used as nanofillers.

In addition to the mineral fillers and organic fillers such as starch or amylose can be added. Starch and amylose may be native, ie non-thermoplasticized or thermoplasticized with plasticizers such as glycerin or sorbitol ( EP-A 539,541 . EP-A 575 349 . EP 652 910 ).

The use of nanofillers is also possible. Nanofillers are, in particular, finely divided phyllosilicates, preferably clay minerals, particularly preferably montmorillonite containing clay minerals whose surface is modified with one or more quaternary ammonium salts and / or phosphonium salts and / or sulfonium salts. Preferred clay minerals are natural montmorillonites and bentonites.

Also, the polymer compositions may contain other biodegradable polyesters such as aliphatic polyesters, aliphatic-aromatic polyesters, polycaprolactone, polylactic acid or polyglycolic acid. The polymer compositions according to the invention are partially miscible with these polyesters or provide stable phase mixtures.

For the purposes of the present invention, the feature "biodegradable" for a substance or a substance mixture is then fulfilled if this substance or the mixture of substances corresponding to DIN EN 13432 has a percentage of biodegradation of at least 90%.

In general, biodegradability causes the polyester (mixtures) to decompose in a reasonable and detectable time. Degradation can be effected enzymatically, hydrolytically, oxidatively and / or by the action of electromagnetic radiation, for example UV radiation, and is usually effected for the most part by the action of microorganisms such as bacteria, yeasts, fungi and algae. The biodegradability can be quantified, for example, by mixing polyesters with compost and storing them for a certain period of time. For example, according to DIN EN 13432 (Referring to ISO 14855 ) Allow CO ₂ -free air to flow through ripened compost during composting and subject it to a defined temperature program. Here, the biodegradability is determined by the ratio of the net CO ₂ release of the sample (after subtraction of CO ₂ release by the compost without sample) to the maximum CO ₂ release of the sample (calculated from the carbon content of the sample) as a percentage defined as biodegradation. Biodegradable polyesters (mixtures) usually show clear degradation phenomena such as fungal growth, cracking and hole formation after only a few days of composting.

Other methods of determining biodegradability are described, for example, in US Pat ASTM D 5338 and ASTM D 6400-4 described.

The polymer compositions mentioned above are suitable for the production of nets and fabrics, tubular films, chill-roll films with and without orientation in a further process step, with and without metallization or SiOx coating. However, the polymer compositions can also be used for injection-molded articles, thermoformed articles or foams.

Application-technical measurements:

Tensile tests were performed on rectangular film strips of the specified thickness ISO 527-3 in standard atmosphere at 50% humidity and 23 ° C performed. The modulus of elasticity was determined at a speed of 1 mm / min, the remaining data at a stretching speed of 125 mm / min.

I. Materials used:

• i (component i)
• i-1, poly-3-hydroxybutyrate-Biocycle ^® 1000 from PHB ISA
• ii terephthalic acid ester
• ii-1 Terephthalic acid bis (2-ethylhexyl) dialkyl Palatinol ^® DOTP BASF Corp.,
•  Plasticizer Comparative System: Tributyl Citrate (TBC) Citrofol B1

General preparation of the polymer blends

Preparation 1 (Examples 3 to 5 and Comparative Examples 1, 2 and 4):

The blends of Table 1 were prepared on a twin-screw mini extruder from DSM. The amount used was 20 g in each case, wherein the starting materials were used in the weight ratios indicated in Table 1. At a temperature of 180 ° C. and a rotational speed of 80 revolutions per minute, component i-1 was first added and, if necessary, components ii-1 or TBC immediately thereafter. After 3 minutes, the mixtures were discharged in strand form and cooled in air. Each experiment was repeated twice.

Table 1: Preparation recipes (% by weight) for the polymer blends of Examples 3 to 5 and Comparative Examples 1, 2 and 4: feedstocks V-Ex. 1 V-Ex. 2 Example 3 V-Ex. 4 Example 5 i-1 * 100 90 90 90 88 ii-1 * 10 20 TBC * 10 20 * based on components i and ii

Press films:

The polymer strands from the mini extruder were cut into small pieces after cooling and then pressed into films by means of an electric hot press from Paul-Otto-Weber GmbH using foamed metal frames of 300 micrometers thickness at 170 ° C. and a final pressure of 200 kN (duration per film per 9 minutes).

Table 2: Mechanical data of the films from Examples 3 to 5 and Comparative Examples 1, 2 and 4: test unit V-Ex. 1 V-Ex. 2 Example 3 V-Ex. 4 Example 5 film thickness microns 229 234 234 264 259 Modulus MPa 1660 998 1238 730 1121 tensile strenght MPa 32.26 20.62 22.48 19,01 20.24 Elongation at break / F-max % 3.87 5.16 5.74 7.66 8.65 tensile strength MPa 32.18 20.60 22.48 18,98 20.26 elongation % 4.16 5.23 5.76 7.82 8.71

Examples 3 and 5 according to the invention were improved in all measured mechanical data compared with the comparison systems.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 99/23146 [0006]
• EP 539541 A [0025]
• EP 575349A [0025]
• EP 652910 [0025]

Cited non-patent literature

• DIN EN 13432 [0028]
• DIN EN 13432 [0029]
• ISO 14855 [0029]
• ASTM D 5338 [0030]
• ASTM D 6400-4 [0030]
• ISO 527-3 [0032]

Claims (8)

A polymer composition comprising: i) from 70 to 95% by weight, based on the total weight of components i to ii, of a polyhydroxyalkanoate; and ii) 5 to 30% by weight, based on the total weight of components i to ii, of a terephthalic acid di-C ₄ -C ₁₃ alkyl ester. The polymer composition of claim 1, wherein the polyhydroxyalkanoate comprises at least one compound selected from the group consisting of: poly-3-hydroxybutyrate, poly-3-hydroxybutyrate-co-3-hydroxyvalerate, poly-3-hydroxybutyrate-co-3-hydroxyvalerate-co-4 hydroxyvalerate, poly-3-hydroxybutyrate-co-3-hydroxyhexanoate and poly-3-hydroxybutyrate-co-4-hydroxybutyrate. A polymer composition according to any one of claims 1 and 2, wherein the polyhydroxyalkanoate (component i) is a poly (3-hydroxybutyrate-co-3-hydroxyhexanoate). A polymer composition according to any one of claims 1 to 3, wherein the phthalic di-C ₄ -C ₁₃ alkyl ester (component ii) is selected from the group consisting of: terephthalic acid di-butyl ester, terephthalic acid bis (2-ethylhexyl) ester, Bis (2,2-dimethylhexyl) terephthalate, di-iso-nonyl terephthalate and bis (2-propylheptyl) terephthalate. Polymer composition according to one of claims 1 to 3, containing 0.1 to 2 wt .-%, based on the polymer mixture i and ii, of a nucleating agent. Polymer composition according to one of claims 1 to 3, containing 2 to 50 wt .-%, based on the polymer mixture i and ii, of a filler. A biodegradable polyester film containing a polymer composition according to any one of claims 1 to 6. Biodegradable injection-molded or thermoformed articles containing a polymer composition according to one of claims 1 to 6.